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October 18

Facial Hair Growth

Does the growth of male facial hair increase by shaving it? Thanks. -Haon 00:40, 18 October 2005 (UTC)[reply]

No. From [1]: "Shaving does not make the hair shaft thicker, darker, or grow faster or slower. However, the short hair shaft may be more noticeable as it grows out because it has a blunt tip instead of the normal tapered tip. " Other sources: Mayo Clinic Snopes "Beardguy" on AOL --Quasipalm 00:51, 18 October 2005 (UTC)[reply]

LEVERS

hey, are tweezers a first, second, or third class lever?

I would say they aren't a lever at all, as they rely on bending the metal (at least the most common design does). A classic lever does not require the lever-arm to bend. StuRat 16:49, 28 October 2005 (UTC)[reply]

Take a look at lever which explains the three classes with examples.-gadfium 02:38, 18 October 2005 (UTC)[reply]

While we are on the subject, has anyone encountered this class system for levers outside of a school textbook? Is it used in the real word anywhere?--Commander Keane 14:02, 18 October 2005 (UTC)[reply]

And what about state capitals, sentence diagrams, long division, times tables, gym, batik and civics. Useless, useless...Brian Schlosser42 17:30, 18 October 2005 (UTC)[reply]

You don't use your times tables?--Commander Keane 17:18, 22 October 2005 (UTC)[reply]

Barometer

How does a barometer work?

There are many types of barometers. look in the article and see which specific kind you're looking for. --Borbrav 05:11, 18 October 2005 (UTC)[reply]

alligators and crocodiles

Which one, the alligator or crocodile, opens it's mouth by raising it's upper jaw and which one opens it's mouth by lowering its bottom jaw? --68.33.167.172 03:34, 18 October 2005 (UTC)[reply]

Based purely on the photograph on the Crocodile article, I would say the crocodile raises its upper jaw. I can't quite tell from the photograph on Alligator, but it looks like it could open it's mouth by moving the lower jaw. --Canley 03:45, 18 October 2005 (UTC)[reply]
- I was under the impression that everything has the upper jaw as part of it's skull and that the only way anything could open it's mouth is through the articulation of the bottom jaw. --Martyman-(talk) 04:26, 18 October 2005 (UTC)[reply]

How to seperate chlorophyll a & b,and carotenoids before doing the Absorption Spectrum of Chlorophyll a

I would like to know the details of the process about seperating chlorophyll a & b,and carotenoids before doing the Absorption Spectrum of Chlorophyll a

Paper chromatography works. first Google HTML hit ("enjoy" the webpage background). I you can read a PDF file, go here. --JWSchmidt 19:41, 18 October 2005 (UTC)[reply]

Drugs and Alcohol

My teacher keeps telling us that alcohol is the only drug that affects every organ of the body because it flows through the bloodstream. But what about heroin when you inject it? What about vicodin and other drugs? Dont they also affect every organ?

Come on. If you eat a candy, the sugar will enter your bloodstream (simplified) and every living cell in you body will eventually nurished by the sugar. If you breath, oxygen will do the same thing. If you drink water ...

Sugar, oxygen and water aren't drugs. DirkvdM 09:57, 18 October 2005 (UTC)[reply]

Tell that to the principal in Missouri who suspended a child for giving another child a drug: a glucose tablet. alteripse 21:02, 18 October 2005 (UTC)[reply]

I don't know what are the receptors of alcohol in human cells. I also don't know if all cells, tissues and organs are responsive to alcohol. I'd like to know the answer. -- Toytoy 09:28, 18 October 2005 (UTC)[reply]

That something flows through the blood doesn't necessarily mean it affects everything. Heroin, for example, is much like endorfins (no article on that? I do spell it right, don't I?), so the body accepts it as something natural and uses it where it is normally used, which is in the brain. But then heroin is a substance the body recognises and this is not the only way something can affect a bodily part. DirkvdM 09:57, 18 October 2005 (UTC)[reply]

endorphin. -- Toytoy 11:11, 18 October 2005 (UTC)[reply]

As with most drugs of abuse, alcohol affects primarily the brain and the liver. Physchim62 13:41, 18 October 2005 (UTC)[reply]

Alcohol is highly soluble in water, whereas the other drugs are not. This means it can pass through tissues. When Alcohol

is consumed some of it actually penetrates the tounge and enters the bloodstream that way. Other drugs do not do that, at least to that extent. It also does not need to be digested to enter the blodstream and can be used as food, sort of. There is a story that certian types of diabetics can take in alcohol in an emergency to keep them alive until help arrives. I do not know how true that story is, though. Read it years ago in readers digest.

Not true. alteripse 21:03, 18 October 2005 (UTC)[reply]

Read about receptors. Most drugs have actions on specific organs because their recptor-mediated actions are generated only in certain parts of the body. Alcohol has effects on cells that are independent of a specific receptor, allowing it to have effects on all cells. The chemical nature of alcohol that gives it the ability to penetrate to all tissues (see above) is also important. --JWSchmidt 14:01, 18 October 2005 (UTC)[reply]

what are the dangers of salvia?

enviroment and its relation with geography

You can find a lot about the environment here at Wikipedia. Environments are frequently affected by geography; for instance, where the geography is below sea level, the environment is usually wet. For a more complete answer, please ask a more complete question. — Lomn | Talk / RfC 13:53, 18 October 2005 (UTC)[reply]

QF 25 pounder Short Mark 1 (australia)

Please, does anyone know when the QF 25 pounder was first manufactured in Australia, and by whom? -- Chris

Our article on the 25 pounder does not contain the information directly, but it does link to LemaireSoft, which refers to a diferent designation: 8.76cm FK 280. A quick google search yields several links, among which this one, which details the history of the weapon. -- Ec5618 11:02, 18 October 2005 (UTC)[reply]

Sales of commonplace automobiles

I would like to know the order of magnitude of the yearly sales of some modern average, commonplace model of automobile (with references if possible). David.Monniaux 12:32, 18 October 2005 (UTC)[reply]

Within the context of your question, please define the terms "modern", "average", and "commonplace". Dismas|^(talk) 13:16, 18 October 2005 (UTC)[reply]

Commonplace = a kind of car commonly bought today (ex: Peugeot 206 in France), i.e. not luxury cars

Average = a market segment that ordinary people buy (i.e. not luxury cars, not sports car)

Modern = produced within the 5 last years David.Monniaux 13:53, 18 October 2005 (UTC)[reply]

Automotive Intelligence has compiled a fair amount of information relating to annual sales for various manufacturers. If you want national figures, most nations have an association of automotive importers and manufacturers who compile such things. --Robert Merkel 13:39, 19 October 2005 (UTC)[reply]

What is the 'Vero cell line'?

Hello, what is the Vero cell line? Regards, Stuart.

Please, search first - it's quicker. Search Wikipedia using the box to the left. A web search could help too.

A google search yielded this file which explains that The Vero cell line (a single cell line) was derived from the kidney of a normal, adult, African green monkey (Cercopithecus). In addition to its use as a vaccine cell substrate, this cell line has been used extensively for virus replication studies and plaque assays.

The rationale behind the use of Vero cells rather than primary monkey kidney cells is that these cells can be banked and well characterized, which avoids the issues of lot-by- Iot variability and adventitious agent contamination of primary cultures freshly initiated for each production run from the kidneys of wild-caught monkeys. In addition, the continued use of animals is problematic from ethical and economic viewpoints. Numerous investigational products are being produced or have been proposed to be produced in Vero cells. -- Ec5618 17:58, 18 October 2005 (UTC)[reply]

Elementary particles

What are WIMP's and MACHO's? Have any been observed so far? Chosen One 17:34, 18 October 2005 (UTC)[reply]

Please search first - it's quicker. Search Wikipedia using the box to the left. A web search could help too. -- Ec5618 17:49, 18 October 2005 (UTC)[reply]

Hey, you don't have to shout, I can understand normal English, well, thank you. Chosen One 19:12, 18 October 2005 (UTC)[reply]

Don't post while intoxicated is my advice. - Cobra Ky

(talk, contribs) 04:45, 20 October 2005 (UTC)[reply]

I'm sorry, but I wasn't shouting, I was copying the exact rule you should have followed, as it is written at the top of this page. Had you read those rules, you would not have had to ask your question, and your linguistic abilities would not have been doubted. -- Ec5618 20:08, 18 October 2005 (UTC)[reply]

Try WIMP and MACHO. — Laura Scudder | Talk 17:45, 18 October 2005 (UTC)[reply]

Laptop and digital camera woes

Okay, since the Peanut Gallery answered my spoiled hamburger question so well, hopefully I can get some equally good advice about my laptop...I have an old (2001 era) Gateway laptop as my backup computer. The fan has died, and for a while it worked OK, so I took it to my brother, a semi-pro electronics wiz to repair. However, as the fan is very hard to come by, he can't fix it. Now, it overheats and goes into safe mode in about a minute. Next week I am going on vacation, and will be taking my Fuji S3100 camera with me. I have one 256 Mb xD memory card, and the idea was that I would use the computer for a few miuntes a day to dump the photos. But now, I can't even do that, as it wont stay on long enough to copy the files. So, I had an idea: What if I keep the laptop in the refrigerator to keep it cold? I know thatthis is not usually a good idea, and that condensation is going to be a problem, but frankly I want to take a lot of pictures more than I want to keep the dying laptop. So, will this work as a way to keep it running for a few more days? I won't need it more than 15 minutes a day, for 7 days. Any ideas? Brian Schlosser42 19:25, 18 October 2005 (UTC)[reply]

The fridge might help, but the problem is more a lack of airflow (where inside-case temps might pass 150°F) rather than ambient temperature. I think you'd have better luck, and far less risk of a short-circuit, fire, or generally dead laptop, if you created some ductwork with paper and tape connecting a desk fan to the fan vents on the computer. It certainly wouldn't be any more cumbersome to work with than typing in the crisper. — Lomn | Talk / RfC 19:31, 18 October 2005 (UTC)[reply]

I have actually used a small external fan to cool my laptop when the internal fan died and it worked reasonably well as long as I wasn't doing anything too processor-intensive. Your mileage may vary. -- WormRunner | Talk 21:29, 18 October 2005 (UTC)[reply]

Ok, no 'fridge. I'm going to buy a desk fan to ventilate it, as this seems to be the consensus. Thanks for the advice, folks. Brian Schlosser42 13:26, 19 October 2005 (UTC)[reply]

Back in the old days I used freeze spray to cool a desktop - if you were prepared to take it out of it's case I'll be you could do the same thing with your laptop! Trollderella 02:39, 27 October 2005 (UTC)[reply]

Some Ballistics

A friend and I have had an ongoing dicussion regarding what happens when someone fires a bullet straight up. As the physic laws state, in a vacuum the speed of the bullet, which is 300 m/s using a common handgun), as it comes down would be the same as when it left the chamber (Parabolic shot). So it would go fast enough to kill someone. However, I believe that because of the small mass and friction with the air the bullet would slow down so much that it is mostly harmless. Am I right? --Threner 21:13, 18 October 2005 (UTC)[reply]

Do not try this one at home. The terminal velocity–the bullet's maximum speed as it falls–depends on its mass and shape. It is definitely possible for a falling bullet to cause injury; such mishaps are a staple at U.S. hospitals around the Fourth of July and New Year's Eve. These injuries are sometimes fatal; whether the victim dies (or even suffers serious injury) probably is affected by the size (caliber) of the bullet, how thick his skull is, and a substantial measure of luck.

Don't look up, either. By doing so you expose the soft tissue and thinner bones of the face, and possibly the major blood vessels of the neck. TenOfAllTrades(talk) 21:31, 18 October 2005 (UTC)[reply]

Any idea of the falling speed? i the article on Terminal Velocity states that a easy way to calculate the speed would be to tie the bullet to a vehicle using a thin string. When the bullet reaches 45 degrees, the speed of the vehicle is the terminal velocity. I really want to try this at home to calculate how fast does the bullet go while falling. I wonder if a bullet at 100km/h could kill someone. Still, at least I know that the bullet slows down enough for it to be not necessarily mortal --Threner 21:38, 18 October 2005 (UTC)[reply]

- - I've read (somewhere, I can't find it now), that somebody measure the terminal velocity of a bullet (I don't know what calibre) as ~90 m s^-1. That would be 200 mph or so. --Bob Mellish 23:26, 18 October 2005 (UTC)[reply]

If you search Google for 'bullet terminal velocity', you get a bunch of handy references, including (in part) [2]:

"Different bullet types behave in different ways. A .22LR bullet reaches a maximum altitude of 1179 metres and a terminal velocity of either 60 metres per second or 43 metres per second depending upon whether the bullet falls base first or tumbles. A .44 magnum bullet will reach an altitude of 1377 metres and a terminal velocity of 76 metres per second falling base first. A .30-06 bullet will reach an altitude of 3080 metres with a terminal velocity of 99 metres per second. The total flight time for the .22LR is between 30 and 36 seconds, while for the 30-06, it is about 58 seconds. The velocities of the bullets as they leave the rifle muzzle are much higher than their falling velocities. A .22LR has a muzzle velocity of 383 metres per second and the .30-06 has a muzzle velocity of 823 metres per second.

According to tests undertaken by Browning at the beginning of the century and recently by L .C. Haag, the bullet velocity required for skin penetration is between 45 and 60 metres per second which is within the velocity range of falling bullets. Of course, skin penetration is not required in order to cause serious or fatal injury and any responsible person will never fire bullets into the air in this manner."

Domain name transfer

What's the simplest way to transfer a domain name? I noticed that someone had a domain name that he wasn't using, emailed him, and he offered it to me for free so long as there weren't any tranfer fees. However, he probably wouldn't feel comfortable just giving me his username and password. What's the easiest way?

Thanks, — Asbestos | Talk (RFC) 23:46, 18 October 2005 (UTC)[reply]

There's not really any transfer fee. In fact, you can start a transfer registration at Dotster(and others) for less than a regular registration(per year). So, it will be less than 9.00 for the entire year after transfer, and you don't have to pay a fee just for transferring. Superm401 | Talk 03:16, 19 October 2005 (UTC)[reply]

Thanks. Also, I currently have a domain name registered under GoDaddy, and am thinking of using them for webhosting as well. With most hosting packages, can you share out the space among different domain names? I noticed Ace-host.net seemed to have one domain/one-hosting space only. — Asbestos | Talk (RFC) 04:33, 19 October 2005 (UTC)[reply]

I don't know about GoDaddy, but I use DreamHost and am hosting seven d o m a i n s with one account, so it seems to vary by company. I'm very happy with DreamHost's services by the way, and would recommend them to anyone. Use this link to check 'em out, and if you sign up, I'll get a referrer bonus. :) Garrett Albright 11:38, 19 October 2005 (UTC)[reply]

October 19

Ink Markers

Can you please tell me what keeps the ink inside markers? Thank You. Susan Thomas ---01:16, 19 October 2005 (UTC)

You mean keeping it from running out? The little wick on the end keeps the small amount of liquid in the case. It actually is flowing all the time, by evaporation through the wick. When you have the cap on, there is very little evaporation. When you press it to paper, clothing, skin or other items to be marked, capillary action allows the liquid to flow. If there is nothing to flow to, not much comes out. Dominick ^(ŤαĿĶ) 02:42, 19 October 2005 (UTC)[reply]

Thanks for the answer...my 9 year old granddaughter thanks you also..

Polynomial bound attainment

Yes, this is homework. But it's only part of the homework, and homework we are encouraged to discuss. And homework whose deadline will almost certainly pass by the time you read this. And yes, me (I, actually) and several others have thought long and hard about this to no avail.

Let P: R^n -> R be a multi-variable polynomial that is bounded below. Does P attain its infimum?

The single variable case can be proven reasonably easily, but the method does not seem to extend to more variables. --Fangz 01:54, 19 October 2005 (UTC)[reply]

Try thinking of the question in this way: Let's take P. Can the bounds on P be of the form [a, b]? What about (a, b)? What about {a, b]? What about [a, b}? What about (-ifty, +ifty), (-ifty, b], (-ifty, b), (-a, +ifty), [-a, +ifty)? If you can think of examples/counterexamples, then essentially you would have answered the question. --HappyCamper 03:17, 19 October 2005 (UTC)[reply]

UPDATE: The answer, in case you are wondering, is NO. Counterexample is (xy - 1)^2 + y^2, along the curve (t, 1/t). --Fangz

Spaces in fixed-width fonts in Microsoft Office Word 2003

When I use MS Office Word 2003 and type in a fixed-width font like Courier, the spaces between the words can get thinner, giving the appearance of right-hand justification even when the paragraph is marked for being flush-left, not right-hand justified. Is there any way to turn that off? It's very annoying. Thanks! --Angr/_{tɔk tə mi} 08:59, 19 October 2005 (UTC)[reply]

Correct me if I'm wrong, but doesn't "flush left" mean that it should adapt the spacing between words to make all lines appear equally long? Use a plain old left justification instead, that'll do the trick. --Pidgeot (t) (c) (e) 14:44, 19 October 2005 (UTC)[reply]

For me, "flush left" is the same as left justification. At any rate, it's not supposed to be fiddling with the spaces between words, and it is. --Angr/_{tɔk tə mi} 18:14, 19 October 2005 (UTC)[reply]

The Program ( MS Office Word 2003, WordPad and NotePad ) uses what the font gives. Your font happens to have a broken space character, making the font Coueier, NOT a mono-spaced font. ( Mono-spaced, means that all characters, even the space occupy a fixed width. ).

You can test it with this test case Text: ( the final I's should all line up too! )

I IIII I

II II II

III IIII

II II II

I IIII I

If all the Is do not line up, then you have a font problem. It may also be using a printer 's version of the font, and not the comptuers version of the font. ( PostScript Printers do this commonly ). ( What Printer and OS are you using? )

Flush-left means that all the first characters on the lines are in a column down the page, and the last characters do not nessesarly line up. (ragged right). If you are using a mono-spaced font, and you use flush-left, and the lines have the same number of characters, the last letter on the lines should line up.

Justify means that ( even with mono-spaced fonts ) that there are enough spaces inserted between words so that the first and last characters on the lines all line up in colums.

But since your using a Microsoft based product, I would get very familar with all the settings. They keep moving 'Use Fractional Width's' around, which makes most output look even weirder. Artoftransformation 08:59, 31 October 2005 (UTC)[reply]

Life on other planets.

If I am correct, the conditions for life to develop on a planet are as follows

Distance from the parent Star. The planet in question has to be in more or less the same orbit as Earth is from our Sun.
The Star itself has to be similar to our Sun. A bigger sun does not last long enough and a smaller one will not be radiant enough for life to develop.
Presence of water. Water is known to be a pre-cursor for life.
Presence of Carbon, hydrogen and Nitrogen which form complex molecules.

see Article Origin of Life, and the work of Stanley Miller. Artoftransformation 09:14, 31 October 2005 (UTC)[reply]

The Question is, if the precursors of life are the same, shouldn't Life on other planets also take the same form that we have taken? Won't other planets also evolve bacteria, fungi, plants, animals and should I dare say Intelligent beings who may look so much like us?
-WarrKay 03:31, 19-Oct-2005(IST)

Not entirely, the distance of a planet can differ, provided the star's radiance fits the position of the planet. Also, the conditions for Planetary habitability are based on what we know. It's quite possible there's life that fits other conditions, but our current scientific knowledge can't prove anything about that either way. - 131.211.50.198 09:56, 19 October 2005 (UTC)[reply]

Nobody knows, but life on earth is so diverse it suggests life could be very diverse elsewhere. Among the most intelligent animals on earth are dolphins, dogs, and octopi, which don't look anything like us. Shantavira 09:59, 19 October 2005 (UTC)[reply]

Re intelligent dolphins, see Hitchhiker's Guide to the Galaxy. ;) Don Diego 10:02, 19 October 2005 (UTC)[reply]

A lot of things in this universe depend on chance. It was only because of our solar system's unique arrangement that life was able to develop here. If life on other planets were to develop in exactly the same way, i.e. following our evolutionary process, the planets would more or less have to be arranged in the same way as ours, and then the timeline has to be the same, etc. Life could evolve also without these precursors. National Geographic produced a series called Extraterrestrial, wherein scientists speculated about the evolution of life on other planets, for example on a gas giant's moon, surrounding a red dwarf, etc. The parameters were changng constantly, and the show itself was very interesting. Don Diego 10:01, 19 October 2005 (UTC)[reply]

One of the important points of evolution is that it is random. Microbes may well be very similar to our Earth ones, but as life evolves further, more differences would emerge. For example, eyes are considered to have started as a random mutation which caused a light sensitive patch of cells. If early beings did not get this mutation, then the entire natural history of the planet would be very different. smurrayinchester^{(User), (Talk)} 10:03, 19 October 2005 (UTC)[reply]

Although light sensitive cells, which eventually lead to the evolution of eyes, are so advantagious that when they do randomly develop they tend to stick around. Which is why the eye has seemingly evolved independently many times. See convergent evolution --Majts 02:53, 20 October 2005 (UTC)[reply]

Life can exist in a much broader range of environments than we're usually taught in secondary school biology; see extremophile. And those are just organisms evolved on earth. The evolution of life on Earth itself was not terribly predictable and involved a great deal of chance- there's a book about this by Stephen Jay Gould called Full House.--Pharos 10:13, 19 October 2005 (UTC)[reply]

Organisms could even develop resistance to UV-rays if they were situated on a planet orbiting a dwarf star. But then again, it depends on the heavenly lottery, where life is going to evolve. Intelligent life, on the other hand, could already possibly exist, although either they are to shy to communicate with us, have tried to remove all traces of their existence so as not to be bothered by stubborn Earthlings, or have not yet developed the technology to communicate with other alien beings. If intelligent life other than our own races existed, I'd dare say that they don't want (or need) visitors from beyond. Don Diego 10:18, 19 October 2005 (UTC)[reply]

No, it won't take the same form, for the same reasons the dolphins can't mate with sharks. Even on earth, the role of chance in evolution is overwhelming, and even where organisms of different origins have evolved similar traits to fit similar ecological niches, they are still very radically different. Alien organisms should be even more different. I think this is one of the stronger arguments against the existence of intelligent alien life - I think that it is as wrong to imagine aliens being intelligent in the way humans are as it is to imagine sharks to act like dolphins, and I have yet to see a convincing definition of intelligence that doesn't boil down too "seems to be like humans". --Diderot 10:53, 19 October 2005 (UTC)[reply]

I would say dolphins are rather similar to sharks (at least the smaller sharks that eat fish). They have similar skin and fins, no hair or fur or feathers, no visible ears, etc. These similarities are remarkable considering how different the evolutionary paths are that led to those creatures. Another example of parallel evolution is bees and hummingbirds, which both independently devloped the ability to hover in flight in order to feed off flowers. StuRat 23:08, 21 October 2005 (UTC)[reply]

I assume that we are talking about life as we know it....Capitan. :-) --Eye 22:15, 19 October 2005 (UTC)[reply]

There are some interesting speculations about additional conditions for life at the Fermi paradox article. --JWSchmidt 00:08, 20 October 2005 (UTC)[reply]

Who says life can't be silicon-based? --65.188.159.140 02:57, 20 October 2005 (UTC)[reply]

Of course, even most mainstream scientists will admit that there's no evidence of any life sustaining planets, anywhere else in the galaxy, and that man is most likely a unique creation--WwJd 04:20, 20 October 2005 (UTC)[reply]

Keep in mind, "life" is only a word; a literal metaphor used to express an idea. This would require us to define what life is. Some suggest fire is alive. It is born in a sense, and it dies in a sense. Fire consumes, and it also reproduces. In this case, if we are to suppose that our definition of life must in some way or another involve DNA, then yes, there are very specific requirements (carbon, oxygen, nitrogen, and hydrogen, as well as a number of other spacial requirements), but as suggested above, why can life not be silicon based? Or an as yet to be discovered form? What I'm getting too is that with this perspective in mind, the universe itself can be seen as alive, and we (being carbon-based lifeforms) are only one of a potentially countless array of possible configurations. - Cobra Ky (talk, contribs) 04:55, 20 October 2005 (UTC)[reply]

Might I suggest an article to open your minds?

Alternative biochemistry- Cobra Ky (talk, contribs) 04:36, 20 October 2005 (UTC)[reply]

The idea that everything is alive sits well with me even if it is only in the spritual sense. --Eye 22:06, 20 October 2005 (UTC)[reply]

Life exists many places on our planet where we humans cannot, although perhaps not sentient life.

North and South Poles
Bottom of Ocean
Inside caves and caverns where there is never any light
Underground (what do worms eat?)
High in our atmosphere
- Around Hot gas vents called Black Smokers
- Around Hot water springs Mud Pots Artoftransformation 09:14, 31 October 2005 (UTC)[reply]

Consider a system with 2 or more stars orbiting each other, or a black hole, or whatever, there's enough radiation there for planets to be further away and sustain life.

Our moon is humogous relative to our planet by average standards, so we evolved with significant tides, very rare as averages in our known universe goes, although telescopes not yet telling us a whole lot about planets around other stars. How come our moon is so large? Well I buy the arguement that once upon a time there was a planet between Mars and Jupiter that broke apart, and a lot of the pieces did not stay where the asteroid belt now is, they flew outwards and inwards, and some were captured by gravity of other planets, one of which being our moon. I recognize that is not the most popular theory of astronomy.

Meteors have been found with fossils inside. How did they get there? Most plausible to me is that when our planet was hit with a really large rock from space that made a crater like Hudson's Bay in Canada, the rock that killed off the dinosaurs, etc. that some of our planet splashed into space, and those chunks of rock had life that became fossilized, but there is an argument, that I cannot follow, that says some of that came from Mars. Assuming these rocks carry simple life that can come off them and thrive again, when given moisture and light, then contamination can travel from planet to planet. AlMac|^(talk) 01:33, 26 October 2005 (UTC)[reply]

See Drakes Equation Artoftransformation 09:14, 31 October 2005 (UTC)[reply]

Brain hyperactivity

Throughout my entire life, I had a problem with "thinking". I always thought way too much about things, all sorts. I can't control it at all, and in several occasions I got headaches and sick because of it. It's physically PAINFUL sometimes (I get tense and my throat, face, neck and guts hurt). I've tried learning relaxation techniques and all, seen psychologists, and even got to a few doctors who offered me some medication (fluoxetine). It didn't work. Recently I had an issue with a friend, partially because of this. I, of course, am feeling terrible about it. The problem is, this led to a major impulse in this thinking pace, and I can barely sleep now. I'm hardly hungry (but I got more thirsty for some reason). And this all scares me. I'm beginning to think there's something neurological behind this. So I set an appointment with a neurologist. I'm not sure if this is the best thing to do, but can't be any harm, eh?

My question is this: are there any sort of neurological conditions that cause this sort of problems? If so, what sort of medical solutions can be taken? If not, what could I possibly do, I've ran out of ideas here.

Attention-deficit hyperactivity disorder, Obsessive-compulsive disorder, and Amphetamine use come to mind. (I'm not a doctor -- you should wait to see your neurologist before jumping to any conclusions.) --Quasipalm 14:28, 19 October 2005 (UTC)[reply]

OCD, perhaps, but the rest? I don't think so. I don't have problems with ADHD, I can focus on things and everything, I just can't control thinking about everything else while I'm at it at the same time. This is what bothers me.

Have you considered meditation? Also I can't help wondering whether you need to get more exercise. Your diet might also be a factor. Shantavira 19:10, 19 October 2005 (UTC)[reply]

Yes I have, along with the relaxation and all... Tried it 15 minutes/day for about a month, and I just couldn't stop these "streams". Also, this triggered some sort of double personality, so I started arguing with myself, inside my head, while I was with this. It's like some other part of me was trying to disturb me. Now, excercise and diet seem more likely to be an issue. I'm very sedentary and my diet is poor (i'm underweight and my diet is not very rich, indeed)...

Proper diet and exercise might well be the cure. Even if they aren't, getting healthier can't exactly hurt, can it ? I particularly think the balance of electrolytes is critical. I have noticed I get muscle spasms when I haven't eaten well, maybe it affects your brain. If, and only if, proper diet and exercise fail to fix the problem, should you consider going to psychoactive meds. They could mess you up, so don't risk it unless you've used up all other options. StuRat 22:57, 21 October 2005 (UTC)[reply]

The symptoms you describe could means lots of things, including a little bit too much anxiety and self-analysis. None of us have any business diagnosing you with anything definite. However, I will offer guidance to the right kind of doctor. Your symptoms undoubtedly fall on the mind side of the old cartesian mind:brain divide. Whether you need reassurance and insight, constructive suggestions, or diagnosis and treatment, you will get more help, more sympathy for the symptoms, and a more experienced perspective from a mind doctor than a brain doctor. I promise I am saving you a step. Good luck. alteripse 23:09, 19 October 2005 (UTC)[reply]

Yes, but I've seen psychologists and they all said the same thing: that I had some self-esteem issue so I was constantly judging myself, and that I'm too anxious with things, so I judge them too often. They sent me to this other guy who gave me the fluoxetine, which, like I have stated, didn't help. BTW, I'm 19.

I would be careful. I was diagnosed with OCD and put on medication. Nothing worked. I had 4 different kinds over 4 years. By then I was a wreck. Finally I found out I did not have OCD. It has taken me years to recover. If the problem is just thinking, then that is not really a problem. If the problem is thinking about the same things over and over without any resolution, that is an anxiety disorder. You are probably very smart and like to think about things, like quantum physics. Arguing with yourself might just be a very pronounced way of resolving inner issues, trying to make decisions. Alteripse is right, though, when saying none of us has any business diagnosing you by 'remote control' this way. Find a good counsellor and get some help, it may be you just have an active imagination. Top priority is to find a counsellor you trust.

I have a similar problem, though nowhere near as serious. I just can't get to sleep because I'm constantly thinking of things. A 'solution' that has worked for me for 25 years is to smoke some marijuana before sleeping. Just a bit works wonders. A big advantage is that if it doesn't help it won't hurt any either. A potential major problem is that it can land you in prison in many countries (I have the good fortune to live in the Netherlands). Although even in the US it's accepted as a legal drug these days, I believe. You'd just need a doctor to prescribe it to you. DirkvdM 15:07, 24 October 2005 (UTC)[reply]

The body is designed to breathe, move (exersize), eat, excrete, socialize and have sex. Your brain will continue to nag you until you give it what it wants. Stop repressing yourself. WAS 4.250 00:58, 26 October 2005 (UTC)[reply]

Define gravitation

Please remember to search before asking questions; see our article on gravitation.

Take a look at gravitation. — Laura Scudder | Talk 16:36, 19 October 2005 (UTC)[reply]

It's also a huuuuge book by John Wheeler, but Laura's link will probably be more helpful. -- SCZenz 16:39, 19 October 2005 (UTC)[reply]

Basic binary sum circuit

I had to create a basic binary sum circuit for my computing class, where three single-digit inputs would be summed to obtain two outputs, one for each digit of the sum (e.g.: if I had 1, 1 and 1 as input, I would get 1 and 1 as output; if I had 1, 1 and 0 I would get 0 and 1, and so on). I can do the first digit no problem - (A xor b) xor C - but I'm having some trouble doing the second digit. So far I have succeded in summing the first two inputs - A and B - but I don't know how to sum the third. Any help? :) Sorry if this explaination is somewhat incoherent, but English is not my native language -- Whitetigah 16:39, 19 October 2005 (UTC)[reply]

Try looking at the adder article. --cesarb 16:49, 19 October 2005 (UTC)[reply]

Thank you, that was exactly what I was looking for :) -- Whitetigah 17:41, 19 October 2005 (UTC)[reply]

astrophysics

why are almost all planets in the solar system coplanar i.e all their orbits lie on a single plane?is it specific only tothe solar system or is it found in other planetery systems?

They are not exactly coplanar. You may read the Protoplanetary disc article for some insight. There is also the issue of outer planets acting like large vaccuums, and removing smaller planetoids, and other bodies with odd orbits. Dominick ^(ŤαĿĶ) 17:13, 19 October 2005 (UTC)[reply]

You might be interested in the discussion on this question elsewhere at the Ref Desk. Note that Pluto's radical inclination is widely believed to result from Pluto's post-creation capture as opposed to the co-formation of the other planets. 199.209.144.218 17:28, 19 October 2005 (UTC)[reply]

Sand bags

Considering the relatively higher permeability of sand compared to clay, shouldn't we ideally be using "clay bags" rather than "sand bags" in a flood?--Commander Keane 17:46, 19 October 2005 (UTC)[reply]

My guess, which is only my guess, is that clay is a lot harder to move around than sand. --jpgordon ∇∆∇∆ 18:02, 19 October 2005 (UTC)[reply]

Sand can be removed later, clay sets and sits in one place. Sandbags collect garbage from the floodwaters and do a surprizingly good job at damming a flood, from my personal FL experience. (Turn Wilma turn!) Dominick ^(ŤαĿĶ) 18:08, 19 October 2005 (UTC)[reply]

That's the great thing about sandbags: even if some water gets through the sand it's clean, so you just have water damage, rather than mud/gunk everywhere on top of water damage. I'd also think that the fact that sandbags naturally reshape themselves to fit their neighbors is a big advantage over clay. — Laura Scudder | Talk 18:35, 19 October 2005 (UTC)[reply]

Sandbags are particularly useful as secondary supports. An unsupported concrete wall can easily be pushed over in a flood, due to the pressure differential between water on one side and air on the other. If sandbags are piled up against the air side, that will substantially eliminate the pressure differential and prevent collapse. StuRat 22:46, 21 October 2005 (UTC)[reply]

A few questions about Hybrid vehicles like Prius

I have a few questions about hybrid vehicles like Toyota Prius. What I want to know is- 1) How much more hybrid vehicles like Prius cost (in %) more than gasoline powered vehicles with similar power and capacity? 2) How many times mileage does Prius or other hybrid vehicles give compared to similar gasoline vehicles? 3) Should we charge the battery that runs the car similar to electric cars? 4) Are all hybrid vehicles automatic geared?

Many of your questions can be answered at hybrid vehicle, or by surfing the web sites of car manufacturers. But here's some quick and dirty answers:

According to Toyota's web site, the Prius starts at US$21,275, whereas the Matrix, which seems to be of a similar size, starts at $15,110. So it's about 35% more expensive. But I'd bet you'd make up the cost in gas savings fairly quickly.
Toyota's site says the Matrix gets up to 30 city MPG, whereas the Prius gets 60 city MPG. Of course, numbers straight from the company like this are always wishful thinking…
No. The battery is actually charged by the gas engine.
That one I'm not sure of.

Garrett Albright 18:51, 19 October 2005 (UTC)[reply]

RE: #3 -- Some people have actually hacked their cars to be able to plug them in overnight at home. See here. They reported that the Prius was able "to reach between 100 and 180 MPG in a typical commute" after the change. So, why don't hybrid cars ship with the ability to plug-in? Reportedly, because car companies were so afraid that people would think that cars that plug in would be annoying or weak, they didn't even build them with the option. Dumb, eh?

RE: #4 -- The Honda Insight has a manual / hybrid version.

--Quasipalm 19:06, 19 October 2005 (UTC)[reply]

The matrix is significantly larger than the Prius, the Prius is more similar in size to the Echo. A better comparison would be the Honda Civic ($14,650) vs. the Honda Civic Hybrid ($21,850), that's a 50% difference in price and averages 15mpg better. That means at 10000 miles/year and gas at $3/gal, The Civic would use 285 gallons of gas a year and the Hybrid would use 200 gallons of gas a year. That means you save a whopping $255 a year, which means you would have to own the hybrid for over 28 YEARS for you to come out ahead. Despite the manufacturer's marketting, Hybrids are still nowhere CLOSE to economically feasible. Even with gas at $5 a gallon, it would take almost 17 years, with gas at an absurd $10/gallon, it would take 8 and a half years. -Drdisque 22:21, 19 October 2005 (UTC)[reply]

Here's a great site, Garrett, fueleconomy.gov. --Quasipalm 23:15, 19 October 2005 (UTC)[reply]

Avian influenza

Is VIRA 38 snake oil or actually capable of reducing the risk of catching avian influenza should it begin to spread amongst humans? Also, is Tamiflu available anywhere via mail-order without a prescription? I'm not freaking out or anything, but Science Friday freaked me out a little last week. (Perhaps it's a good time to re-read The Stand ;-) --Quasipalm 18:56, 19 October 2005 (UTC)[reply]

I'm having trouble finding published research on "VIRA 38". As far as I know, the neuraminidase inhibitors such as Tamiflu have only been tested in short-term experiments. It is not clear to me that they are the solution to a flu pandemic. The idea that the world should stock pile these drugs in order to limit a pandemic seems to be a good way for a few drug companies to make a lot of money. It may be that the money would be better spent on ways to limit exposure of humans to the avian flu virus and development of vaccines. --JWSchmidt 23:53, 19 October 2005 (UTC)[reply]

A vaccine cannot be developed until the virus mutates into a form that can cause the pandemic. There is a delay of 4 - 6 month before enough vaccine can be produced. So the idea is, that antivirals will reduce the death toll in the meantime. Theresa Knott (a tenth stroke) 23:57, 19 October 2005 (UTC)[reply]

A human vaccine for the avian flu virus has already been reported ("AVIAN INFLUENZA: 'Pandemic Vaccine' Appears to Protect Only at High Doses" by Martin Enserink was in Science, Vol 309, Issue 5737, 996 , 12 August 2005 doi:10.1126/science.309.5737.996b). If actions (such as vaccination) were taken to protect against infection of humans by existing avian flu virus, then there would be a reduced chance of a mutant form evolving that would easily transfer between humans. There can be some protection from antibodies to a type of flu (like H5N1), even if the antibodies are made against a different variant of the type. If humans were vaccinated against the existing H5N1 type bird flu, there would be some protective antibodies that would cross-react with new mutant strains. I'm not saying that the neuraminidase inhibitors are useless, but I'm not sure that they are the best way to throw money at the problem, particularly if it just turns into a matter of those few who can afford the inhibitors getting them via mail-order. --JWSchmidt 00:33, 20 October 2005 (UTC)[reply]

Pulseless Electrical Activity PEA (EMD)

Hello, I hope you can help with this enquiry, I am currently on a medical course and have just failed a practical assesment. I was following the protocol as I understood it in that I shocked my PVT patient four times until their rhythm changed. What I saw was a sinus rhythm and checked the carotid pulse and was told that there was a weak palpable pulse. I interprited this as sinus rhythm and gave AV for one minute and re analysed patient. On completion I was told that the patient had been in PEA and should have commenced CPR. Am I way off the mark or can you as was explained to me by the assessor a palpable carotid pulse in PEA?

Many thanks Alastair Palmer --62.189.84.170 18:57, 19 October 2005 (UTC)[reply]

A Google yielded our Pulse article, the baseline Emergency Medicine guideline to palpate for carotid pulse for 10 or more seconds as a preliminary for CPR, and some additional guidelines for performing immediate surgery. It looks like the technique is fundamental for physicians. But a further Google using the exact wording on your question also indicates this is a pre-terminal condition with a 5% survival rate, so it is unclear to me why CPR for PEA (EMD) is more than a stopgap; a 3rd Google shows that the CPR responder should also be requesting Advanced cardiac life support (ACLS) at the same time. Thanks for posting the question. But the Google hits make me wonder whether the symptom lack of carotid pulse=>CPR is consistent with weak palpable pulse. What did the assessor mean by this? Ancheta Wis 10:31, 21 October 2005 (UTC)[reply]

Infinity

Many years ago I remember my maths teacher saying that mathematicians didnt use infinity in equations. Something to do with things not adding up. I was never interested in maths but that has always stuck in my head. Is this true? If it is true how then does science deal with infinity when the language of science is maths and infinity in terms of the universe is ..well .a distinct possibility.--Eye 22:12, 19 October 2005 (UTC)[reply]

You can't use infinity as some form of quantity, because when you try and do tricky things with it, things break down. Sure, inf + inf = inf, 2*inf = inf, but what is inf/inf? (Suppose inf/inf = a, then inf = a inf. You can choose any such a and the equation will still work). There are other cases like this.

However, infinity can be a useful symbolism. If you want to express the sum 1/2+1/4+1/8+..., you can write it as

\sum _{i=1}^{\infty }{1 \over 2^{i}}

but really, this is the same as saying

\lim _{n\rightarrow \infty }\sum _{i=1}^{n}{1 \over 2^{i}}

where the "lim" means the limit as you let n get larger and larger.

So infinity is more like a concept than a quantity. Lots seem to get entranced by the idea of infinity, so you should get a large response here... Dysprosia 22:35, 19 October 2005 (UTC)[reply]

(Added after edit-conflict so might be parroting Dysprosia a bit).

The thing with infinity is that it really makes no sense. Take for instance the classical example of divison by zero. Lets try dividing 5 by zero:

{\frac {5}{0}}=\infty

Ok, so far, so good. Well, that must mean.....

{\frac {5}{\infty }}=0

Sure, sure, ok, good.....

{\frac {5*\infty }{\infty }}=0*\infty

Hmm, where are you going????

5=\infty *0

What???? Infinity times zero equals 5!!! Cool!! Anyway, the point is, when you treat infinity like a normal number (ie you put it in formulas and subject it too normal algebraic operations like cancelling out factors from a divison), ridiculus stuff happens. When math has to deal with infinity (and infinitismals), such as in calculus we replace them with limits. A limit is basically a number that goes "very, very close" to a certain point (such as infinity or zero). For instance, to find the derivative of the function x^2 (if you don't know what a derivative is, don't worry, it doesn't really matter) you have to simplify this equation:

{\frac {x^{2}-(x+h)^{2}}{h}}

Where h is a number that is an infinitismal (ie an "infinitly small number", a number as small as possible). Normally, this would break the division by zero-rule, but if we impose limits we can work with it.

\lim _{h\to 0^{+}}{\frac {x^{2}-(x+h)^{2}}{h}}

\lim _{h\to 0^{+}}{\frac {x^{2}-(x^{2}+2hx+h^{2})}{h}}

\lim _{h\to 0^{+}}{\frac {2hx-h^{2}}{h}}

\lim _{h\to 0^{+}}{2x-h}

Now, since h is so tiny that it really doesn't change the result anymore (since it's basically 0), we can safely remove it and the limit and get the answer, 2x. This is a bit (alot) simplified since you are a non-mathematician (so am I btw, I'm a serious dilettante), but that's the gist of it. gkhan 22:54, 19 October 2005 (UTC)[reply]

Mathematicians definitely do use infinity, although for reasons the above posters mention, you must use care, or you'll end up in trouble. There are in fact several different numbers which could be called infinity. There is the infinity in the extended real line, which satsifies a bunch of things like infinity + any number = infinity. The expression infinity*0 is left undefined (no one claims that infinity*0=5). Other infinities include omega and aleph nought, and many more. -Lethe | Talk 01:06, 20 October 2005 (UTC)[reply]

Of course any discussion of infinity (you have at least skimmed that article right?) would be lacking without a mention of cardinality of infinity. That is something that blows most peoples minds when they first learn of it because they are used to the conventional wisdom of infinity being the biggest thing out there. How could there possibly be different sizes of infinity? Well at least in set theory there is. - Taxman ^Talk 18:17, 20 October 2005 (UTC)[reply]

I think you people are deliberately trying to confuse me. :-) --Eye 20:14, 20 October 2005 (UTC)[reply]

If $1/\infty =0$ then one might assume that the infinity being referred to is countable. However, if one accepts the existence of countable infinity, then by set theory (see Cantor's diagonal argument), one must also accept the existence of uncountable infinity. If the reciprocal of countable infinity is zero, then surely the reciprocal of uncountable infinity is also zero? Of course. But then what is the reciprocal of zero? Is it countable or uncountable? It cannot be both, because if 1/0 is equal to both infinities, then the two infinites are equal to each other, which they are not, by definition. So paradoxes such as these blow up in one's face, and one must conclude that infinity is somewhat beyond ordinary grasp.

It depends on what field of numbers one is dealing with. The field of real numbers does not include infinity even though its cardinality is uncountable infinity. So when one asks "how many real numbers are there?" the answer is not a real number. Real numbers are good enough for practical purposes: infinities being dealt with as limits. However, it is possible to define other mathematical structures which include things which are called "infinities". For arithmetic, see surreal numbers. For geometry, see projective geometry.

Physics is based on the ability to take measurements of physical quantities, such as mass, distance, and time. When an experimental physicist makes a measurement, the instrument which makes the measurement is finite, and the number resulting from that measurement is finite. Physical theories are confirmed by being tied down to experiment (see empiricism) and physical experiments always give finite answers. Physics deals with infinities by getting rid of them, by hook or by crook: see regularization and renormalization.

Mathematics, on the other hand, is rationalistic and not empirical. Mathematical structures are tested by self-consistency: if it is not self-consistent, it does not exist. Each mathematical structure is self-contained and independent of other structures, so Euclidean geometry and Riemannian geometry each have their own separate existences, even though they would contradict each other. (Likewise, the theory of infinity has two branches, one which accepts the continuum hypothesis, another which rejects it: but each branch capable of being self-consistent.) Moreover, mathematical structures do not have physical existence. The number five does not physically exist. One might have five finger's on one's hand, but the five fingers are not the number five. One might draw a red number 5 on a paper, but that five is not the concept of number five. The symbol $\infty$ for infinity is not itself infinite. The symbols which mathematicians manipulate on paper are all finite. Infinites are known only indirectly, through logical inference, and inhabit a non-physical realm. So when one says "There are a countable infinity of natural numbers", those numbers do not really exist physically. Besides, if mathematics only dealt with infinities, it would be impractical and rather useless and mathematicians would not gain their bread, whose quantity is finite, positive, and non-zero, which they eat regularly in order to obtain a finite, positive, non-zero amount of energy (see pragmatism). On the other hand, mathematics does have a corner of its realm permanently reserved for infinities: as Hilbert said: "No one can drive us from the heaven which Cantor created for us." —Anonymous, 20 October 2005

What's infinity + -infinity? Jazz1979 10:58, 30 October 2005 (UTC)[reply]

+ (inverse )is a arthmatic operation, and might not be valid on non-numbers. The algebra of infinity is a subset of mathamatics called Non-Standard Analysis.

See this link: [Types of Infinities ] to Summarize: infinity + a constant = infinity .: infinity + - infinity = a constant.

For a more precise definition: [[http://www.math.vanderbilt.edu/~schectex/courses/infinity.pdf%7C"Georg Canor (1845-1918): The man who tamed infinity." Artoftransformation 09:57, 31 October 2005 (UTC)[reply]

October 20

Computer science and math skills

I'd like to know just how skilled one would have to be at mathematics in order to go into the field of computer science. After reading some articles on the subject here on Wikpedia (which I could barely understand, if at all) it seems like a fascinating field. Impaciente 01:09, 20 October 2005 (UTC)[reply]

Computer science is broken into several branches, including computer engineering/architecture which requires some technical skills to learn what component functions are, computer programming, which is oriented towards learning languages and a form of qualitative logic that is needed to understand the workings of the code of the program, and then, computer networking and information technology, which is concerned with computer services and networks. In computer programming, generally very little math is required, but that is only in my experience. Pick out books or articles about certain regions of comp-sci and find your way through the subject.--Screwball23 02:02, 20 October 2005 (UTC)[reply]

My experience has been that computer science doesn't require a complex mathematical background. In completing my Bachelor's degree, I would have only encountered complicated mathematical formulas once or twice (in case you are wondering, Data Communications and a subject on Artificial Intelligence). Apart from these two instances, I think a sound knowledge of algebra and problem solving will probably get you through (bear in mind I am Australian, so maybe your education system is a bit different). Ranglin 02:56, 20 October 2005 (UTC)[reply]

However, if you want to become an computer science researcher, as distinct from a practising programmer/software engineer, mathematics skills become a lot more important. A friend of mine did a PhD in the computer science department at Princeton University; he didn't write a single computer program during that period. His work was entirely mathematical. Much of theoretical computer science is essentially a branch of discrete mathematics, there may be a lot of statistics in some areas, and many topic areas (such as computer vision) require a fair bit of mathematics.

In any case, while higher mathematics may not be strictly necessary to become a computer programmer, the mindset that it teaches you is a very valuable skill in becoming a good one. Maths is good for you :)--Robert Merkel 03:08, 20 October 2005 (UTC)[reply]

While this is generally true, it is possibly to get even a PhD in CS if you are not so good at math (although it is hard in practice). There are some areas within CS that require less math, notably systems. Having said this, it really really helps if you are good at math. First, because fundamentally programming is logic (i.e. math), and you have to be good at programming to get a CS degree. There are, however, people who are bad at math and good at programming, although this is not common. Second, to be a good programmer, you really need to understand certain concepts which are mathematical in nature (e.g. computational complexity). One thing to remember is that the kind of math one needs for CS is different from the sort of math one is used to in high school or math college courses. In particular, calculus is not especially important. Ornil 05:05, 20 October 2005 (UTC)[reply]

I first went to university hoping to score a degree in computer science. However, my high school had an experimental math program known as College Preparatory Mathematics that sure as hell didn't prepare me for college math, and I scraped by with a D- in pre-calculus, a class that didn't count toward the degree anyway. I gave up and switched to English literature. However, I know how to program; I've been writing programs of various degrees of complexity since I was twelve or so, and the most complex thing I've run into is parabolic equations. So really, even though higher math isn't seen so much in programming in the real world, you do need to have a knack for math to get a degree in computer science. Garrett Albright 14:04, 20 October 2005 (UTC)[reply]

I'm an application programmer speciallizing in CAD and database apps. While I have used advanced math up to calculus in some of the applications (calculating component masses for center of gravity analysis), this is just my case, not typical. I would say a typically programmer won't have to deal with more than basic math, perhaps time math and percentages being the limit (used for benchmarking how much faster one version of a program is than another). Knowing how to extrapolate a graph is also quite useful..."If the program can process 10 items in one second and 100 items in ten seconds, it should take how long to process 1000 items ?". If you work with graphics, some knowledge of geometry is also needed, such as the formulae for distance and a circle. StuRat 22:22, 21 October 2005 (UTC)[reply]

I majored in math in college because it was my favorite and best subject in high school, then discovered to my dismay that college math is a totally different subject than high school math, then was pleased to discover that college physics is very similar to high school math, so I switched majors. Out of college, I discovered that what I had learned in college had no correlation with what the job market was looking for, talk about not planning ahead, but most everyone that way. I went into computing because of an illusion that there was some relationship between computers and math, and found that from perspective of the end user, and the worker in the field, computers have as much to to with knowing math, as driving an auto has to do with knowing how the auto works inside the engine. About the only mathematical stuff I have needed in a multi-decade computer career has been decent estimating skills. I mean write a program to get certain answers. How do you know it is getting right answers? How do you know you not have a rounding error? Well in my brain I can get ball park answers to compare with computer answers. AlMac|^(talk) 01:44, 26 October 2005 (UTC)[reply]

Excel column headings

I'm using Excel 2003. Every worksheet comes up with numeric headings at the top of columns. How can I change this to alphabetical headings? I've searched the Excel section of the Microsoft Office 2003 All In One manual but without finding a solution. I have a feeling I'm missing something pretty basic, but what?

Erasmus 02:12, 20 October 2005 (UTC)

Go to Tools/Options/General and deselect "R1C1 reference style".-gadfium 02:48, 20 October 2005 (UTC)[reply]

Thanks, Gadfium, it works beautifully. You've saved me hours of thrashing around. Erasmus.

Who manufactures the buses of the so-called "Wiki Wiki" shuttle line at Honolulu International Airport?

The buses are owned by the State of Hawaii and operated by Airport Group International. Who is the manufacturer?

Example photo: http://www.futureofthebook.org/blog/archives/wikiwikibus.jpg .

I don't recognise the badge logo, and the picture is too low-resolution to zoom in and tell that way.

Why not contact the operators and ask? --Robert Merkel 03:32, 20 October 2005 (UTC)[reply]

What are the interrelationships between science and technology?

Our Technology article states: "The lines between science and technology are not always clear. Generally, science is the reasoned investigation or study of nature, aimed at finding out the truth, generally according to the scientific method. Technology is the application of knowledge (scientific, engineering, and/or otherwise) to achieve a practical result (Roussel, et.al.)." Capitalistroadster 08:09, 20 October 2005 (UTC)[reply]

It's a very big and complex question. Scientists create technology in order to do science (think of Galileo and the telescope), but it is also often a case of a solution looking for a problem (nobody was enthusiastic about PCR when it was invented, for example, because they were worried about different problems than the one it would eventually solve). Sometimes technologies in a broader sense are derived from scientific understanding (the nuclear reactor from nuclear fission, for example), though the conversion is in no means usually simple ("reduction to practice" is often quite difficult, because no technology is reliant on elementary scientific notions alone). On the other hand, there are technologies which were created without any reference to scientific knowledge — in many cases the technology comes first and is understood by the science later.
In short, they are very interrelated activities, and the forms of causality (what causes what) goes both ways at different times, and at times they have nothing to do with each other at all. Hopefully that answer gives you some food for thought. If you want to read an interesting book about the relationship between invention and science, I recommend Thomas Hughes, American Genesis: A Century of Invention and Enthusiasm. --Fastfission 16:54, 20 October 2005 (UTC)[reply]

CCE

What does "CCE" in various Atari 2600 games stand for? (some exposition or exhibition?) Thanks.

CCE was the (unlicensed) company that used to sell some Atari 2600 games and other stuff here in Brazil (and apparently in the rest of South America too). I suppose that ROMs with the CCE text were ripped from Brazilian\South American cartridges. EDIT: take a look at this page I found too ☢ Ҡieff | Talk 06:00, 20 October 2005 (UTC)[reply]

On another note, the company still exists and its products are worthless than junk. ☢ Ҡieff | Talk 07:43, 20 October 2005 (UTC)[reply]

Opening Matlab

I currently have Matlab installed on my computer. But when I open the program it gets to the initalising stage and then closes again. So far I have tried reinstalling windows and also resinstalling the service packs. But it still wont work. Does anyone have any ideas on the cause or solution to this problem, would be of great assistance.

I don't use Matlab myself, so I'm probably of little help in that regard, but I'd like to tell you to be careful about reinstalling Windows. It may break settings you've had or if there's a problem, kill your computer altogether. Only try reinstalling Windows as a last resort in the future. - 131.211.51.34 07:22, 20 October 2005 (UTC)[reply]
- Matlab seems to do a lot of thing on startup, so a diagnosis will be interesting. It may check to see how many concurrent licences are running on the network etc. Try searching Mathworks support for some help. I dug up Problems Starting Matlab which might be of some use. Good luck!--Commander Keane 11:16, 20 October 2005 (UTC)[reply]

Breakdown of a trillion dollars in ways people can easily understand.

Hello, all. I have a question/favor to ask. This question may be in a wrong column for asking, but here it is. Long time ago, I saw in a newspaper with a columnist showing and explaining just how much a trillion dollar is, in a sense of talking about national debt, and to make it easier for everyday folks to understand, there was a breakdown of a trillion dollars on this column. A broad general example would be that a trillion dollars is enough money to buy 30 NFL football stadiums, 100 3-carat diamond rings, 100 Corvettes, and still have a lot of money to buy or do other things. For some reason, a columnist's name Dave Barry comes to mind. I may be totally wrong on who this columnist was back then, but if anyone out there has any positive feedback or information or the article on it, I would really appreciate the information. Thanks.

Porc

Which trillion you're talking about? I don't know which is used in USA. ☢ Ҡieff | Talk 07:53, 20 October 2005 (UTC)[reply]

It would be the US trillion, as the British trillion is far more money than exists on Earth. StuRat 22:03, 21 October 2005 (UTC)[reply]

According to Wordnet on answers.com, the US usage is one followed by 12 zeros see [4]. Everywhere else, it is one followed by 18 zeros. As to your question, I don't know but Dave Barry sounds plausible see [5]. Capitalistroadster 08:18, 20 October 2005 (UTC)[reply]

Everywhere else is not true. ☢ Ҡieff | Talk 09:22, 20 October 2005 (UTC)[reply]

Not to miss the point, but that sounds like kind of a crappy explanation of a trillion (american i guess) dollars. By my count, you could buy 97 $10B stadiums, 100,000 $200k Ferrari F1 Spiders, and 100,000 5 carat diamond rings (for $80k ea.), and still have money ($2 billion dollars) left. You know, for what its worth. (edited for more casual numbers). --Jmeden2000 21:45, 20 October 2005 (UTC)[reply]

I do remember a picture-based representation of how big a stack of bills you would need to represent a certain very large amount in cash, but I don't remember where I saw it (it was very impressive though). But I found this via a quick search (see second paragraph). Tzarius 10:03, 21 October 2005 (UTC)[reply]

A trillion dollars is enough to give everyone on Earth a color TV. WAS 4.250 01:10, 26 October 2005 (UTC)[reply]

"Unit" means "Mols"?

Hi all, a quick question. I'm doing some calculations on drug dosage, and I often come across statements like "This formulation contains 10 units of Pitocin per mL". My question is, when they say "units", do they mean "Mols"? Or is it some arbitrary unit that they've come up with? I suspect they do mean "Mols" (or "Moles"), but I want to be sure, and I can't find anything on Google. Can anyone help? For an example of the usage I'm referring to, see[6]--inks ^T 09:16, 20 October 2005 (UTC)[reply]

I'm not sure if it matters. Just ensure that your final answers are in terms of units e.g. "he should be fed 5 units every 24 hours." Charlie123 (Talk) 10:09, 20 October 2005 (UTC)[reply]

The use of 'units' or 'international units' for pharmaceuticals is in many ways a relic of the age before really high quality analytical chemistry. For a given drug or preparation, one 'unit' was the quantity of drug that produced a specific biological effect. (One unit of antibiotic X would inhibit the growth of a specific number of bacteria, for example.)

By measuring the potency of a drug through a biological effect, manufacturers didn't have to know the concentration of active ingredient (if the active ingredient was known), the concentration of different enantiomers, or the effect of different related active molecules. They just had to test each batch for biological potency and then slap a label on the jar. There's no specific conversion factor to go from 'units' to 'milligrams'; since international units are defined in terms of a biological effect, the conversion factor is different for each drug. (You can look up the conversion factor for most drugs, however.)

Now that we've gotten better at pharmaceutical chemistry, we can do two things that are gradually making measurement in 'units' obsolete:

We can produce very pure drugs with a single active chemical ingredient, and
We can measure the amount of active ingredient very precisely.

Hope that helps. TenOfAllTrades(talk) 11:49, 20 October 2005 (UTC)[reply]

Have a look at International unit -- Rune Welsh | ταλκ | Esperanza 14:32, 23 October 2005 (UTC)[reply]

According to Goodman and Gilman's textbook, the potency of Pitocin was originally determined by its ability to cause changes in vascular smooth muscle contraction. One unit is about 2 micrograms of oxytocin. --JWSchmidt 03:12, 24 October 2005 (UTC)[reply]

Computer upgrade

We have a set of pentium 20 computers and we would like to upgrade all our computers to pentium 4 confuguration.We had been suggested to upgrade the same by using a node concept which means to insert a card for each computer in a common server ,from where all the computers would be upgraded. We would like to have your opinion for the same.

By

shubhada

(formatting fixed --David Wahler (talk) 13:09, 20 October 2005 (UTC))[reply]

What are you trying to upgrade? Disk space? -- Ec5618 13:13, 20 October 2005 (UTC)[reply]

Maybe he wants a network-boot (PXE) setup? Tzarius 09:53, 21 October 2005 (UTC)[reply]

Instead of a single server, perhaps 2 servers would be better, allowing you to backup half at a time and still keep the others operational, for example. Also, if one server goes down you would still have half of your computers able to communicate with one another. StuRat 21:58, 21 October 2005 (UTC)[reply]

This is a Brilliant solution for some types of networks Artoftransformation 10:03, 31 October 2005 (UTC)[reply]

It depends completely on the current and planned usage of the computers. If your doing websurfing ONLY, then this might work, but you'll need a fast server.Artoftransformation 10:03, 31 October 2005 (UTC)[reply]

Similar Question: Id like to paint a small room, but faster than Michelangelo(11+ Years), but with higher quality? I dont mean to demean your question, but more information is definatly needed.

Liquid Leaking out of my hard disk

I have a clear liquid leaking out of an external hard disk - any ideas what it could be? Oil for the motor perhaps?After a shave 15:42, 20 October 2005 (UTC)[reply]

What ever it is, you should back up all the data off the disk pronto! Wierd behavior from disks is a sign of imminent failure. smurrayinchester^{(User), (Talk)} 17:02, 20 October 2005 (UTC)[reply]

Are you sure it wasn't fluid that once leaked INTO the disk enclosure making its escape? Most new drives are using fluid dynamic (oil-packed) bearings but i always thought the amount of fluid was trivial and wouldnt be enough to 'leak out' anywhere if it were compromised. See Fluid bearing for more info. Is the drive behaving in any abnormal way like overheating, noise, vibration, etc? --Jmeden2000 20:23, 20 October 2005 (UTC)[reply]

Those are bits leaking out! Danger! --jpgordon ∇∆∇∆ 22:55, 20 October 2005 (UTC)[reply]

Maybe the hard disk watched too much TV, or played too many games, and now its brains are turning to mush. ;) Don Diego 11:51, 21 October 2005 (UTC)[reply]

Thanks guys. The disk has gone to heaven. It was making a grinding noise before death. All data is backed up tho... I have taken it apart, and I am quite sure that no liquid got in. Ah well After a shave 15:09, 21 October 2005 (UTC) :*Obviously it means your hardrive is too wet, you should try putting in a dryer, I hear strong electromagnetic fields are good for hard drives and other data storage devices--4.237.23.16 18:26, 22 October 2005 (UTC) Stupidty stricken out. Proto t c 12:18, 28 October 2005 (UTC)[reply]

How much virtual space exists in persistent worlds?

I am curious what a reasonable estimate of virual space might be in persistent worlds, such as MMORPGs. In particular, how does this amount of terrain compare with the earth.

Considerations, (please modify if so inclined)

Equate the most common form of transport with driving a car at ~50mph.
Estimate with and without duplicate shards or instances
Estimate with and without non-persistent worlds, whatever persistent world is defined as...

Take it and run.. I'm not an active player on any MMORPGs at the moment, but would consider including even worlds such as LambdaMOO. My idea of space that qualifies is any electronically-provided 3D space a live individual is navigating simultaneously with other live individuals. (No, bots are not alive). ∴ here…♠ 16:29, 20 October 2005 (UTC)[reply]

It doesn't sound like an answerable question.... How big a number can you make up? Virtual terrain is just a scenery on a coordinate system, how big it is, is infinitely variable. Do you include areas from text-based games? Do you count randomly-generated dungeons? Do you count or the areas that can be gotten to, or just the populated areas? Do you count multiple instances of the same area? If you want my guess, I'd say you'd get maybe a third of a major continent from the foot-based MMOGs. If you count the flight/vehicle based MMOs, you could probably run over a few Earths. Tzarius 09:49, 21 October 2005 (UTC)[reply]

The nice part about games like CoH is that you can measure the size of the world -- it tells you. However, you also have to take into account the fact that in CoH the day is 60 minutes long, so there's a 24x time (and therefore, ostensibly, space) compression. I'm just going to give a guesstimate figure here, but given that Independence Port is about 2.5 miles long in game, at a 24x compression it'd be about 60 miles long in "real world" terms. Likewise, characters would be moving through it at 24 times their speed in game. That having been said, if you took length and width estimates, you could use that factor to calculate how many square feet exist in the CoH world. --FreelanceWizard 08:04, 23 October 2005 (UTC)[reply]

Gynecologist Paradox

I'm just perplexed, how can a male, heterosexual gynecologist still have a sex drive to have an intercourse with his wife after all day long looking at naked women? Thanks

Professionalism ☢ Ҡieff⌇↯ 17:33, 20 October 2005 (UTC)[reply]

You'll find that a lot of men do tend to bring their work home :-) but I have to admit that's one that I've often wondered about --Eye 18:53, 20 October 2005 (UTC)[reply]

A gynecologist is not going to find every woman he works on attractive. Besides, if he gets aroused by naked women all day, why wouldn't he want to release the sexual tension and have some fun with his wife? Just looking isn't going to be enough and if he wants to keep his job he'd better not have sex with his patients. - Mgm|^(talk) 20:53, 20 October 2005 (UTC)[reply]

A good doctor is trained to be have professional objectivity. Thus he does not think of the women as 'naked', they are patients only.

Which body parts are considered sexual arousing on sight is purely cultural. In our own society there was a time when the sight of a woman's ankles was considered sexual, so such people might well have asked us "how can you still be interested in your wife if you see strange women's ankles all day long ?". There are many societies where breasts are exposed, and a few where full nudity is practiced. In such societies, the sight of those things lose their sexual allure. Contact with those areas is another matter, however. StuRat 21:49, 21 October 2005 (UTC)[reply]

Yahoo dormant email accounts

Imagine I dont log in to Yahoo mail for many days. After how many days or months will my messages be deleted? Will my address also be deleted and recycled after a few days/months?

Surely Yahoo! knows that answer best? - Mgm|^(talk) 20:54, 20 October 2005 (UTC)[reply]

I know that the account itself will never go away as Yahoo user accounts are permanent. -Drdisque 21:11, 20 October 2005 (UTC)[reply]

Not necessarily. Yahoo blocked my account after I didn't use ot for half a year. Unfair. Don Diego 23:01, 20 October 2005 (UTC)[reply]

But it's recreatable. User:Zoe|^(talk) 21:09, 23 October 2005 (UTC)[reply]

Consumption of electricity of speaker and fan

1) Does a speaker consume same amount of power >when the volume is low and >when the volume is maximum?

2) Does a Fan consume same amount of energy irrespective of whether it runs slow (minimum speed) or fast (maximum speed)?

No and No. However, the average power consumption of a speaker is quite low, so (barring a concert setup) you can safely assume "Yes" for the first one. Fans and other devices with motors pull more power, so it's easier to get a meaningful difference. Note that all of this, however, is relative: a desk fan's power consumption difference is probably meaningless if it's running off mains power yet significant if running off a battery. — Lomn | Talk / RfC 20:16, 20 October 2005 (UTC)[reply]

A speaker transforms electrical power into sound, so a speaker at a loud volume will be transforming more energy. Since power is the rate of change of energy, this is more power. The speaker transformation is lossy, so not 100% of the electrical power is transformed. Speakers are often rated in watts, which is the maximum power they can handle, often in RMS but some are rated at peak power. A fan turns against air and bearing friction, and similarly, draws more current as it turns faster. Dominick ^(ŤαĿĶ) 20:18, 20 October 2005 (UTC)[reply]

Buckminsterfullerene/Buckyball

What are the bond lenght and bond angle of buckyball? Some web-sites said it has single bond and double bond, while some web-sites said its bonding like benzene, is not single bond and double bond, is somehow between single and double bond. I can't find any information of the bond angle of buckyball, so please help me--

If I remember correctly, buckyballs are made up of benzene rings in a soccer ball shape. Bonds in benzene are delocalized meaning that while you may draw the double bonds on one please there's also a structure where all double bonds are shifted one place. Since elektrons in such structures tend to move around, there's no way of knowing for certain where they are, so each of the bonds could be both single or double, which means they are something in between on average. - Mgm|^(talk) 21:02, 20 October 2005 (UTC)[reply]
- No, buckminsterfullerene is not made up of benzene rings. It is made up of hexagons and pentagons of carbon, much like a soccerball. That means the bond angles are 120 and 108. I don't know and can't find the bond lengths right now. Also, the electrons are apparently NOT delocalized as Mgm says, and you never "know for certain where they [the electrons] are" whether they are delocalized or not. A simple google search will be more helpful to you than asking here. - Rangek 18:45, 22 October 2005 (UTC)[reply]

How about the bond angles of carbon between pentagon and two hexagons? And, is the bond lenght equal to 144pm(benzene bond lenght)?

In fact, I have searched in google, but there are not much information about details of buckyball structure. Does carbon inside buckyball have sp2 orbitals? But sp2 orbitals' all bond angles are 120 degrees. If not, which orbitals should it has?

Presumably the carbon atoms in buckyballs are indeed sp² hybridized. The bond angles may not be exactly 120°, but they're close enough; for an example of what really strained bonds look like, see cubane.

What you have to remember is that atomic orbitals are just approximations. In principle one could (as far as we know) determine the exact electron densities in a buckyball by solving the Schrödinger equation. This just happens to be somewhat difficult in general. —Ilmari Karonen 23:16, 24 October 2005 (UTC)[reply]

why is the Earth a sphere

why is the Earth a sphere - ????

For a given volume, a sphere has the least amount of surface area. Bubbles, water droplets, and stars also share the same shape for this reason. Dominick ^(ŤαĿĶ) 20:21, 20 October 2005 (UTC)[reply]

The Earth is spherical because it possesses sufficient mass to (approximately) collapse itself uniformly via its own gravity. Smaller astronomical bodies of similar density (like asteroids or Phobos and Deimos, the moons of Mars) do not have the necessary gravitational attraction and remain decidedly non-spherical.

Of course, it's worth noting that the Earth isn't precisely a sphere, even if you discount mountains, etc. The Earth's rotation imparts an equatorial bulge, and (if I recall correctly) the Southern Hemisphere is generally elevated with regards to the Northern Hemisphere. You can get into more detail on this at Figure of the Earth or from Isaac Asimov's book The Double Planet (an excellent read). — Lomn | Talk / RfC 20:29, 20 October 2005 (UTC)[reply]

The equatorial bulge is, if I recall, bigger than even the biggest mountains, in the sense that the north pole is something like 8 miles closer to the center of the earth than the equator is. -- SCZenz 21:40, 20 October 2005 (UTC)[reply]

To understand the above you have to realise that the Earth is largely non-solid. Only a relatively tiny crust at the surface is solid rock. DirkvdM 15:49, 24 October 2005 (UTC)[reply]

Sudden Change

Imagine I invented a machine that could morph something say like a rhino into a banana. I put the rhino in at one end and a banana comes out at the other end. (Yes it would be a big banana). Anyway imagine that I could watch the process and this process could be viewed in ratio terms. The change would first be 99 rhino and 1 banana then 98/2 and so on. As I watched the process I would have to decide whether or not the thing I was viewing was either a rhino or a banana as it clearly could not be both. It is either one or the other. When the rhino gets down to 51/49 it is still a rhino and not a banana. A point will arise where in order to complete the process of change the morphing rhino will have to leap the divide of the 50/50 point to become a banana. I say leap because it could not be possible to exist as two things at the same time It could not exist on the 50/50 point. To one side of the 50/50 it is a rhino, to the other side of 50/50 it is a banana. If infinity exists then the process would never cross the 50/50 point because the process would be infinitely dividing down towards the 50/50 point but never quite reach it… or as it came close to the 50/50 point the process would stall … until enough pressure for change had built up to cause it to leap the divide. Would the rhino suddenly change into a banana or gradually change? Is this a fair analogy of say, changing systems in nature, where evolution stays the same for donkeys years and then suddenly there is a big change. Or physics where an atom can absorb so much energy before suddenly jumping up to a higher energy level. Or say global warming, will our earths weather system under go a sudden change if enough pressure builds up? How close could we be to that change? Will I ever stop asking questions? :-) --Eye 20:24, 20 October 2005 (UTC).[reply]

IMHO, this is not a fair analogy, no conclusive proof has been offered for global warming, and the notion is unfortunatly unable to be determined given the political climate. In many places things have been getting hotter, and in some colder. Superimposed on this is the warming and cooling that occurs over centuries. At one time Greenland was pretty pleasent, and able to grow crops, now it is not. Dominick ^(ŤαĿĶ) 20:30, 20 October 2005 (UTC)[reply]

AFAIK, global temperature has been rising pretty steadily for a while. There isn't any debate over that, just over the idea that itis caused by human activities. -Superiority 01:40, 30 October 2005 (UTC)[reply]

Your analogy describes a Zeno paradox which, while an amusing word play, doesn't really enter into reality—despite all arguments to the contrary, Achilles really will outpace the tortoise. That said, some transitions in nature mirror this: electrons exist at distinct energy levels. However, macroevolution is more correctly viewed as continuous, as are trends in global climate. As for the final questions, they're philosophical. — Lomn | Talk / RfC 20:34, 20 October 2005 (UTC)[reply]

Just read some of the Zeno thingy. Isn't life fun.. :-)--Eye 20:45, 20 October 2005 (UTC)[reply]

An infinite series of times can actually add up to something non-infinite. Say you're doing the last percent, and you're "infinitely dividing it" - so 51%, 50.5%, 50.25%, 50.125%..... But, you need to remember you're also dividing up the time needed to perform the task. Also, pretend you have a super-camera that takes a picture every time you "divide it". If the process takes, for example, 100 seconds, you're taking "snapshots" at 49 seconds, 49.5, 49.75, 49.875..... You might be taking an infinite number of "snapshots" (and you can assemble them into an infinitly long movie), but your snapshots don't slow down time! Also, the first half of a percent takes half a second, then the next quarter takes a quarter of a second, then the next eighth takes an eighth....and it all adds up so that the last 1 percent takes 1 second. There's no paradox at all. AySz88^-^ 20:52, 20 October 2005 (UTC)[reply]

In chemistry substances that change into others often have transition states which is a form in between the other two, which is actually neither rhino nor banana (if I were to keep to your analogy). Technically speaking, the rhino would stop being an actual rhino the moment it wasn't 100% rhino anymore. - Mgm|^(talk) 21:06, 20 October 2005 (UTC)[reply]

The rhino/banana thing was actually part of another thing I was thinking about to do with acid/alkaline. (Since you mentioned chemstry.) If the same analogy was used as the above rhino/banana scenario would a solution be classed as an acid until it became an alkaline? Is it possible to have a perfectly neutral solution?--Eye 22:29, 20 October 2005 (UTC)[reply]

Theoretically, yes. In the real world, small impurities are excluded, so a very, very weak acid could be classified as a neutral solution, until the basicity rises significantly. Regarding your rhino, maybe halfway through it would be a Very Confused Rhinoceros, Unless You Put the Head In First, In Which Case, It Would Be A Very Blissfully Ignorant Fruit. Incidentally, time flies when you're having fun, but fruit flies like bananas (and rhino-bananas, ergo). ;) Don Diego 22:58, 20 October 2005 (UTC)[reply]

I think you had better start by building a rhino-banana machine, and find out. Seriously though, you mentioned that the process was transitioning at one percent per measured interval, 100/0, 99/1, 98/2, etc. and it would have no reason to change as it approached 50/50. I have a machine that turns water into ice, and it doesn't slow down and stop for any so-called 'halfway'. The postulate you are hinting at is something that quantum physics is trying to deal with, in particular the Uncertainty principle. When is something what it is, and not something else? The basic answer is that as you measure it, it is what it is, and beyond your ability to measure it, it lies in an uncertain state, ready to jump to any possible state only when youre ready to come along to find out. It's been suggested that many thresholds apply to our universe, mostly from physicist Max Planck who suggested that there is a point beyond which it would require infinite energy to make an accurate measurement, and since that's not possible, for all you know everything exists in quanta of that particular level, and no more detail is possible. There is much reading available on the subject. --Jmeden2000 17:23, 21 October 2005 (UTC)[reply]

Regarding the comparison with evolution, I don't believe evolution ever moves "instantly" from one species to another, but do believe it moves quicker at times and slower at other times. We might choose to classify one individual as one species and it's offspring as another, but that is just due to the way we classify things, there wasn't necessarily a large jump between the two individuals. I would say periods of rapid evolution happen due to changes in environment (including the food supply and predators) and enabling changes in the species itself. In primates, for example, the opposable thumb originally evolved as a way to hold onto tree branches, but enabled tool use as well. This led to a rapid evolution of intelligence in primates to make use of this capability. StuRat 21:33, 21 October 2005 (UTC)[reply]

Not sure if this is helpful, but there are exampels of natural systems that suddenly switch mode. Transition of fluid flow from laminar flow to turbulent flow is one. As you increase the speed of water flow, the pattern doesn't change much. Then, over a very short range of speed it suddenly switches from one pattern to another. Above that the pattern stays relatively constant in the new pattern. The same could (could) easily apply to cilmate change. DJ Clayworth 20:40, 25 October 2005 (UTC)[reply]

solubility of hydroxylapatite vs. pH

I am trying to find out how the solubility of hydroxylapatite depends on pH. I have searched through a number of reference books, but I've been unable to find an answer. Ideally what I would like is a chart of pH vs. solubility for this mineral. Thanks if you can help! ike9898 20:51, 20 October 2005 (UTC)[reply]

If you have access to scientific journals, through a library or university, you could have a look at some of the articles that appear on this Google scholar search. -- Rune Welsh | ταλκ | Esperanza 14:19, 23 October 2005 (UTC)[reply]

Red/turquoise contrast problem.

I have noticed that if a strong red and a turquoise or blue-gray border on one another, I find it very difficult to look at. It's not a kind of colour-blindness, because I can clearly see the difference between the two; actually, it's more like the contrast is too great to see properly. The border appears to sort of crawl and it is unpleasant to focus on. If I see these two colours bordering one another even in my periphery it is distracting, almost as if something is blinking or moving in my periphery. Does anyone know what this is? Is it common? Bryanmtmorrison 21:01, 20 October 2005 (UTC)[reply]

I have experienced that also, and discussed it with others, so I can tell you that other people see the same thing. ike9898 22:07, 20 October 2005 (UTC)[reply]

While the area we focus on sees the most detail, the periphery is good at detecting movement. In your case it sounds like the "threshold" for seeing movement is too low, and you eyes/brain detects movement that isn't really there. StuRat 21:19, 21 October 2005 (UTC)[reply]

Carbon

what are 4 uses of carbon?

You can use it to do your own homework--see the rules at the top of this page. But I bet reading our carbon article would be a real good place to start. -- SCZenz 21:38, 20 October 2005 (UTC)[reply]

I'll bite:

—Ilmari Karonen 23:00, 24 October 2005 (UTC)[reply]

Oh you are cruel. DJ Clayworth 20:34, 25 October 2005 (UTC)[reply]

Plants Of The Amazon Jungle

While watching a programme on T.V. I came across an unfamiliar word- Aseyi Berry- it si supposed to be the berry of palm trees. I am not certain of the spelling.

You'll be wanting our Açaí Palm article. :) --Ashenai (talk) (Galatea!) 22:42, 20 October 2005 (UTC)[reply]

white film on magnesium strip, plz help ASAP

Ok, before doing an experiment, why should you polish and remove white film off a magnesium strip?

That white film is a layer of magnesium oxide, which forms when magnesium is exposed to air. Presumably, you want to do an experiment on magnesium, not magnesium oxide, so you first must clean the film off to get down to the magnesium underneath. — Laura Scudder | Talk 23:22, 20 October 2005 (UTC)[reply]

well, do you want to experiment on pure magnesium, or do you want your results tainted by the presence of oxidation and impurities? Lethe | Talk 23:23, 20 October 2005 (UTC)[reply]

On pure magnesium, THANK YOU VERY MUCH

How to find experimental percent composition of magnesium and oxygen in Magnesium oxide?

How do you do such thing?

Please do your own homework. Hint: Mass increase. -- Ec5618 23:39, 20 October 2005 (UTC)[reply]

These are a little bit complicated, can some one help? To be more exact, I started with 0.16 g of Mg after heating it, I ended up with 0.24g of MgO. I want to find the experimental percent composition of magnesium and oxygen in Magnesium oxide.

Bigger hint: have a look at the articles on magnesium and oxygen and find out the atomic mass of each. From that you should be able to figure it out.

No, that will give you the theoretical percent composition. Oxygen is rarely analysed in elemental analysis, magnesium is usually analysed by atomic absorption spectroscopy. Or maybe your teacher just wanted you to say that your 0.16 g of magnesium are still present in your 0.24 g of magnesium oxide... See also Antoine Lavoisier. Physchim62 03:53, 21 October 2005 (UTC)[reply]

Actually, not just the theoretical mass distribution. When you burn the magnesium, it will gain weight. A negligible amount of magnesium will be lost. Where did that 0.08 grammes of weight come from? 0.005moles of .. Ok, I'm done hinting now. -- Ec5618 11:35, 21 October 2005 (UTC)[reply]

Surely we've got a magnesium oxide article? - Mgm|^(talk) 08:16, 22 October 2005 (UTC)[reply]

Are you sure you burned all of your magnesium. It may be better to use a thinner wire or shavings so it burns completely. - Mgm|^(talk) 08:18, 22 October 2005 (UTC)[reply]

October 21

Coulombs law

How does one calculate a question like this:

Two charges with specified values for charge, which are held a distance apart, an extra charge is introduced and is moved along the line they are on. Where would the new charge experience a zero resultant force?

---MJH

Set up a coordinate systemm that seems easy to you, like putting one of the stationary charges at x=0. Add up the forces from each of the two charges (from Coulomb's law) on the extra charge, making sure the signs are right for the directions they point. Then solve algebraically for when the sum of forces is zero. -- SCZenz 00:08, 21 October 2005 (UTC)[reply]

Can you elaborate a little more? What do you mean by sum?

Normally it would be a vector sum, but in this case the problem is one dimensional. I mean write down the force from coulomb's law from each charge separately, using your chosen coordinate system for both (your r's will have to be changed), and then literally add up the numbers. (Make sure the signs are right to reflect the direction of the forces!) -- SCZenz 00:35, 21 October 2005 (UTC)[reply]

Internet Protocol

Question: what is a Level 2 Internet Security Protocol

Answer: do your own homework. Hint: Find out what level 2 means by starting at OSI model. --Robert Merkel 13:27, 21 October 2005 (UTC)[reply]

Also compare SSL and IPSec. --R.Koot 15:46, 21 October 2005 (UTC)[reply]

(Neither of which is a level 2 protocol.) Gdr 10:55, 22 October 2005 (UTC)[reply]

rosenberg generator

hi wikipedia. myself rutuparna andhare. i want to know information about the rosenberg generator. this is a special purpose m/c. i want its construction, working and digram. my e mail id is (removed)

Hi Rutuparna. You might need to try some books on electrical engineering for this kind of detail; all we have at Wikipedia is the article on motor controller. Maybe some electrical engineering or mechatronics people will be able to give you some more specific help. Sorry I can't be of more assistance. --Robert Merkel 11:53, 22 October 2005 (UTC)[reply]

I am an EE, and I used to teach. I have not used or been in contact with a "Rosenberg generator" if you have any basic details, I would love to fill in the article. I think it is a DC Motor/generator, thats only by looking at litarature that didn't say much except what I told you. Amusingly enough, google returned some link to the free power and perpetual motion crowd. I found no vendors for such an item, but I have not looked at the stack at my workplace. If you want someone to build you one, or tell you how to build one, this is beyond the scope of wikipedia. Dominick ^(ŤαĿĶ) 14:07, 22 October 2005 (UTC)[reply]

Light in a box

Why can't you trap light in a mirrored (on the inside) box? When I first asked my dad this, he told me that if you cut off the source of the light when shutting the lid, the wave can't exist inside the box. This doesn't satisfy me, however, because light can still travel through space, and, indeed, be bounced off mirrors, after a star has died.

Say light is coming from a distant star. I bounce it off one mirror and set up another mirror far away parallel to it. Would it keep bouncing between them? The energy decreases rapidly with distance because it all disperses, sure, but the same would not be the case in an enclosed-on-all-sides box.

I'm guessing that it's because the mirrors absorb energy with each bounce and that, in the tenth of a second it takes me to close the box and open it again, the light has bounced around a zillion times and lost all its energy. Is that right? And would it be theoretically possible to have a perfect mirror in which this energy loss (if that's what it is) didn't occur?

Sure it's possible. In fact, there are perfectly legitimate standing waves of light in classical electromagnetism. And yes, what really happens if you bounce light a lot is the energy gets turned into heat on the walls of the box. -- SCZenz 04:43, 21 October 2005 (UTC)[reply]
If you can rig up a strong enough magnetism or gravity source, you can trap light without having it lose energy, just by keeping it in a stable orbit. (which might be a bit tricky with magnetism). Tzarius 09:34, 21 October 2005 (UTC)[reply]

light is neutral, and so will not be affected by electromagnetism (neglecting quantum effects). Gravity would work, however. but the radius of a lightlike orbit is on the order of the Schwarzschild radius, so if you want to trap light with gravity, you'd better have a black hole handy. -Lethe | Talk 09:46, 21 October 2005 (UTC)[reply]

But there is light inside a box, just light that you can't see. When the light bounces off the walls, it doesn't lose all its energy, it shares that energy with the walls of the box. When everything has calmed down (very, very quickly), the light and the walls have the same "energy" (strictly, the same temperature), and you can't tell them apart. See also black body radiation. Physchim62 12:50, 21 October 2005 (UTC)[reply]

The very best mirrors that you can make use special optical coatings and reflect about 99.999% of the incident light (in a narrow wavelength range). They are used for cavity ringdown spectroscopy. If you place a pair of them 0.5 m apart, light bouncing between them drops to about 0.1% of its starting intensity after 345000 round-trip bounces, or about 1.1 milliseconds after the light starts. So even with extremely good mirrors, and ignoring all other factors, the light doesn't stay around for very long. --Bob Mellish 15:45, 21 October 2005 (UTC)[reply]

I Like this kind of question. Think of another.--Eye 16:49, 22 October 2005 (UTC)[reply]

how to prepare soft drinks?

Prepare them for what? Could you please clarify your question a bit more? -- Daverocks 12:03, 21 October 2005 (UTC)[reply]

See, for example, OpenCola. TenOfAllTrades(talk) 13:04, 21 October 2005 (UTC)[reply]

Some simply open the container and drink it. You open the cap and pour it over ice. A slice of lime as a garnish is sometimes used. Optionally, rum can be added to Cola, to make a Cuba Libre. In rural areas of the United States cola without rum it is a common breakfast beverage. Soft drinks without coloring, preferably lemon lime flavors, can be used to clean automotive battery terminals. Dominick ^(ŤαĿĶ) 14:14, 21 October 2005 (UTC)[reply]

It's only a Cuba Libre if there's a lime. Without the lime, it's a Rum and Coke. :) User:Zoe|^(talk) 21:05, 23 October 2005 (UTC)[reply]

If you are asking how they are prepared in restaurants, most use a machine which blends soda water (seltzer) and syrup. Bottled soda (premixed) is sometimes also available. StuRat 21:01, 21 October 2005 (UTC)[reply]

lightning?

can the energy (electricity) in lightning be saved or stored? why, how or why not?

mckeancharles@(email removed)

I suppose if you had a really big capacitor hooked up to a lightning rod, you could store the electricity, but all in all, you would save about 500 Megajoules, or 139 kilowatt hours, which would save you between £8 and £15 pounds ($15 - $25) (at 6p per kWh). Not all that worth it. smurrayinchester^{(User), (Talk)} 14:15, 21 October 2005 (UTC)[reply]

BTW, don't post your email address here. Spammers read this page too. smurrayinchester^{(User), (Talk)} 14:17, 21 October 2005 (UTC)[reply]

The problem is that lightning is so irregular that collecting it would require millions of lightning rods all over the collection area. The strength of each bolt is quite different, too, so you would need to be able to handle the maximum case to prevent your equipment from getting fried. Then you would need an efficient way to store the energy until needed. The cost of all this far exceeds the benefit, at least at the currrent cost of electricity. Perhaps some future technology, like balloons carrying thin metal fibers, can make it profitable. StuRat 21:09, 21 October 2005 (UTC)[reply]

Mind you, actually, if lightning strikes the Earth 100 times a second as some people say, covering the entire planet in lightning conductors could save about £800 per second, or £69,120,000 per day. Of course, the cost of installing the billions of rods needed would probably take years to recoup. smurrayinchester^{(User), (Talk)} 09:32, 22 October 2005 (UTC)[reply]

One billion rods with collection mechanisms and connectivity to the power grid would be rather expensive, especially those built in Antartica, over oceans, etc.

Let's say they could each be built for £1,000,000. That would put the total cost for 1,000,000,000 rods at £1,000,000,000,000,000. At £69,120,000 per day that would take 14,467,592 days to pay off, which is close to 40 thousand years. I doubt if they would last that long.

A more practical approach would be to only place rods in areas of frequent lightning strikes, like the top of hills in areas of frequent thunderstorm activity. I still doubt if such a system could be made profitable, however. StuRat 14:29, 22 October 2005 (UTC)[reply]

I suspect it's still a losing game. The CN Tower in Canada (according to our article) is struck by lightning about 75 times per year. The Empire State Building (according to various offsite pages) gets about a hundred strikes per year. If we optimistically assume that the best locations are three times that good, then we get three hundred strikes per year times twenty dollars per strike: $6000 per year. (That assumes that the storage and redistribution of the electrical energy is 100% efficient.) I can tell you that storing a 500 megajoule lightning strike is going to cost a lot more than that.... TenOfAllTrades(talk) 14:54, 22 October 2005 (UTC)[reply]

I'm not convinced by any of this millions of rods stuff. Lightning takes the route to Earth that has the least electrical resistance. By definition that's where it needs to go. If there's a whopping great capactitor in the way it'll avoid it. Shantavira 16:04, 22 October 2005 (UTC)[reply]

Crocodilians in Guatemala

I've been watching this season's edition of the reality show Survivor, which takes place in Guatemala. The contestants are living in two camps along the banks of some unnamed river. This river is infested with lots of crocodilians. Now, the contestants and the host keep calling these things "crocs". "Oh, so-and-so was almost eaten by a croc!" "The winning team will receive a swim cage, 100% croc-proof." But I could've sworn that Central America had alligators and not crocodiles. Searching around on the web, I've found the same confusion on various websites.

So which is it? Does Guatemala have alligators or crocodiles? What's menacing these people? And are they really known man-eaters? --BrianSmithson 14:06, 21 October 2005 (UTC)[reply]

Both caiman and crocodiles [7] [8] are in Guatemala. Krieky! Alligators (new world 'gators) are in the lower United States. [9] I used the University of Florida site, also known as the Gators. Such reptiles till attack a lot of things moving in murky waters, but do not prefer human flesh to other types of food. Dominick ^(ŤαĿĶ) 14:20, 21 October 2005 (UTC)[reply]

P.S. The Caiman is classed as an alligator, but is not the common 'gator that you may be familiar. Dominick ^(ŤαĿĶ) 14:22, 21 October 2005 (UTC)[reply]

Muchos gracias! For the first few episodes, I kept screaming, "Those aren't crocs, you idiot! Those are alligators!" Guess I should be voted out of the tribe. I suppose the animals they keep showing could be caimans, though. BrianSmithson 20:58, 21 October 2005 (UTC)[reply]

I may be totally talking out of my hat, but I believe you can tell caimans from crocs by their teeth -- when the mouth is closed, you can't see a croc's teeth, but you can see the caiman's. User:Zoe|^(talk) 21:03, 23 October 2005 (UTC)[reply]

All about health

Q1. For how long has a brush been in use that will reduce its plaque removing ability up to 30% than a new one?

Q2. How many hours does a baby spend in a baby walker that will delay its first step by up to 4 days?

Q3. Less than how many hours of sleep a night will run a person 2 to 3 times the risk of heart attacks?

Q4. What waist measurement or over is thought to increase a person's risk of getting a heart attack?

Q5. How long did people need to train with weights per week in order to lower their risk of coronary heart disease by 23%?

Q6. After what age would people start losing muscle mass and strenght caused by hormonal changes?

Q7. What % of man who took annual holidays would be less likely to die of a heart disease than those who'd skipped time off?

Q8. How many mililiters of cooked soya beans would contain the protein equivalent of a 110 gram hamburger or 500 mililiters of milk?

Please let me the answers. My email address is <removed> Thanks and regards Raj Ramoo

Almost all of these questions suffer from a problem of overspecificity. They ask a question that due to natural variability in the subject, there cannot be a specific answer to the question. For example, in #1 variation in material used would likely have a great impact on the length of use before it's usefullness declined. Also many of these may or may not have ever been specifically researched, or if they have, to use the first one as an example, the toothbrush companies keep the information secret to try to gain a competitive advantage. In other cases, such as #7, there may be a certain study that found a number, but that doesn't mean that number is accepted fact, and wouldn't be contradicted by another study. Again, the variation is just too great. - Taxman ^Talk 15:29, 21 October 2005 (UTC)[reply]

Q8. How many mililiters of cooked soya beans would contain the protein equivalent of a 110 gram hamburger or 500 mililiters of milk?

Protein contents according to the USDA food nutrition database (in 100 g edible portions):

Soybeans, mature cooked, boiled, without salt: 16.64 g

If your hamburger means meat + bread, then 110 of hamburger roughly equals to 88 g of cooked soybean. However, the volume of the soybean depends on the way you pack it. You can squeeze the cooked beans into a cup or just put the dry/cooked beans into a measuring cup.

McDonald's Hamburger: 12.36 g
Burger King Hamburger: 14.18 g
Wendy's Classic Single Hamburger, no cheese: 12.63 g
Fast foods, hamburger, regular, single patty, plain: 13.69 g

If you hamburger means beef patties, then 110 of ground beef roughly equals to 167 g of cooked soybean.

Beef, ground, 75% lean meat/25% fat, patty, cooked, pan-broiled: 23.45 g
Beef, ground, 85% lean meat/15% fat, patty, cooked, pan-broiled: 24.62 g
Beef, ground, 95% lean meat/5% fat, patty, cooked, pan-broiled: 25.80 g

Currently I am out of milk so I don't know how heavy is 500 ml of milk (936 ml = about 1000 g, I guess). I'll assume 500 ml of milk weighs 534 g.

534 g of milk roughly equals to 107 g of cooked soybean.

Milk, whole, 3.25% milkfat: 3.22 g
Milk, reduced fat, fluid, 2% milkfat, with added vitamin A: 3.30 g
Milk, lowfat, fluid, 1% milkfat, with added vitamin A: 3.37 g
Milk, nonfat, fluid, with added vitamin A (fat free or skim): 3.37 g

Soy protein is fairly "complete". It is comparable to milk or meat proteins. -- Toytoy 15:27, 25 October 2005 (UTC)[reply]

Q6 "After what age would people start losing muscle mass and strenght caused by hormonal changes?" At the average of 32, your putitary gland stops producing hormones. Within 3~5 days, ( the halflife of growth hormones is about 1.5 days ) you start loosing musle mass. The varibility of the average age is 1.6 years, ( at least it was when the study I read in 1988 was published. ). It is rapid until the age of 44, then levels off. Much research is still going on regarding this question, and the mechanism for it. It relates to the extension of life expectancy. Ill look for recent studies. Artoftransformation 12:55, 30 October 2005 (UTC)[reply]

Q5. How long did people need to train with weights per week in order to lower their risk of coronary heart disease by 23%? I believe its less than 13 minutes. Once again. Old data. Artoftransformation 12:55, 30 October 2005 (UTC)[reply]

Water

If 84% of sea water is evaporated every day, why isn't water salty? Please have the answer in soon. Contact my email: (removed)

If you read the top of this page, you'll find that we don't reply by email. But to answer your question, it's because the water evaporates and leaves the salt behind. (I'm not sure what your 84% statistic means though. -- SCZenz 15:05, 21 October 2005 (UTC)[reply]

I'm positive that statistic is false. --Quasipalm 18:05, 21 October 2005 (UTC)[reply]

Well, "why isn't water salty" doesn't exactly make sense. Sea water is, indeed, salty. --Borbrav 20:57, 21 October 2005 (UTC)[reply]

I think he/she means why isn't all water salty. - Akamad 23:51, 21 October 2005 (UTC)[reply]

In that case, river and lake water is continually replaced by fresh water, in the form of rain, and the salt is washed out to the ocean. An exception is a terminal lake, which does not lead to the ocean, then salt does accumulate. Such lakes, like the Dead Sea in Isreal/Palestine and Salt Lake, Utah, USA get extremeley salty, even more salty than the oceans. The only limit is when the salt reaches it's solubility level in water and deposits on the shores and bottom of the lake. StuRat 14:10, 22 October 2005 (UTC)[reply]

Some bodies of water do not get salty, if there is no salt in the surronding geology to leach into the water. Fossilized water, water stored underground that is not flowing, sometimes is not salty. Florida has a few depositsof water that do not flow, and do not get salty. I think the OP was wondering if "84%" of the water evaporated why are the oceans not supersaturated. The answer is that 84% of the water does not evaporate. Dominick ^(ŤαĿĶ) 14:16, 22 October 2005 (UTC)[reply]

The atmosphere has water in it, some of which falls to earth (rain, snow, etc), and every day some of the water on the Earth evaporates back into the atmoshere. Around 84% of the water that evaporates back into the sky evaporates from the oceans, but is replaced by the water that returns to the oceans (rain, snow, rivers, etc.) so the water content does not change day to day (but does change century to century). The stuff dissolved in the oceans varies measureably place to place and century to century. WAS 4.250 01:39, 26 October 2005 (UTC)[reply]

INDIA

Development of India in the field of science and tecnology.

Without a complete question it's hard to determine what it is that you're looking for. Perhaps you should read the article on India and its associated articles and then maybe come back with a more solid question. Dismas|^(talk) 17:12, 21 October 2005 (UTC)[reply]

India has developed. To the extent that it knows to put an "h" in technology, and much more. It will continue to develop. If you want a better answer, do your own homework!. Physchim62 17:13, 21 October 2005 (UTC)[reply]

You could look at articles in Category:Science_and_technology_in_India. Indian science might be a good starting point. -- SCZenz 17:14, 21 October 2005 (UTC)[reply]
And please realise the search box is on the left of the page. -- Rune Welsh | ταλκ | Esperanza 14:05, 23 October 2005 (UTC)[reply]

concerning the ontological status of dimensions.

Hello, My question is, what is the ontological status of a dimension? Is its status objective, i.e., a characteristic of reality or of a thing in reality (these are different answers) or subjective, i.e., a way in which we perceive reality? Thank you, Arnon Shahar. --217.132.229.134 17:55, 21 October 2005 (UTC)[reply]

As a scientist, I have to say I'm not sure how we would tell. Assuming they're a property of reality is very helpful in making physical models. Also, there are physics models with an extra dimension, or even 7, but they include evidence of why we don't see such things normally. -- SCZenz 19:34, 21 October 2005 (UTC)[reply]

The word "dimension" can be used to refer to psychological realities (perceptions), mathematical structures, or aspects of scientific theory backed by empirical evidence. As a math structure space can be infintely divisible. As used in an empirical scientific theory, there is always a smallest as yet verified divisibility. As used to refer to psychological realities, new agers and others find no limit to their ability to misuse scientific sounding words. WAS 4.250 01:52, 26 October 2005 (UTC)[reply]

Partial vs total differentiation

The Stackelberg competition article gives the condition for a Nash equilibrium as ${\frac {\partial \Pi _{1}}{\partial q_{1}}}=0$ . I don't see why this uses a partial derivative, rather than a total derivative and asked the question (with more details) on Talk:Stackelberg competition#term missing a while ago. Can anyone confirm or refute my suspicion that this is an error, please? Common Man 18:25, 21 October 2005 (UTC)[reply]

mathematically, it seems to depend on whether q1 and q2 are independent or not. I don't know anything about economics, so I'm not sure. The phrase "given the output of the leader (firm 1), the output that maximises the follower's profit is found" seems to suggest that q1 should be regarded as fixed (given) and the value of of q2 which maximizes with respect to that fixed q1 is sought. In that case, the partial derivative is correct. -Lethe | Talk 19:07, 21 October 2005 (UTC)[reply]

You're right - your argument holds for the value of q2. So the first pair of equations (involving Pi_2) need to consider the partial differentiation. Now that you pointed this out, I see why someone would use partial differentiation for Pi_1, for the sake of symmetry. It's clearly more elegant. But is it right? (Drilling further down, I realize that this distinction is somewhat arbitrary anyway. Arguably, the Pi_2 equation seems like a mongrel between a partial derivative (with q1 constant) and a total one, since P and C_2 are explicitly differentiated. This is getting ugly!) Common Man 20:09, 21 October 2005 (UTC)[reply]

Incidentally, could someone take a stab at clarifying the beginning of the article? Speaking as a layperson, I'm having real trouble figuring out what the heck Stackelberg competition actually is. TenOfAllTrades(talk) 20:39, 21 October 2005 (UTC)[reply]

As a start, noted that the context of the article is in game theory. Ancheta Wis 22:09, 21 October 2005 (UTC)[reply]

Thanks for the answers, but this is actually, as the headline says, a question about partial vs total differentiation. I'm neither an economist or game theoretician either. But trust me, you don't have to be one to answer the original question. It is pure mathematics. As a first step, maybe I should ask the following context-neutral question:

Given

f = f(x,y,z)

y = y(x)

z = z(x)

We know that

df/dx (where y=constant and z=constant) is called partial derivative

df/dx (where y=y(x) and z = z(x)) is called total derivative

What do you call

df/dx (where y=y(x) and z = constant)

and what's the mathematical notation for it? Common Man 22:36, 21 October 2005 (UTC)[reply]

It is a partial derivative as well. For a boundry condition? My experience in calculus is for electromagnetics, not game theory. Same notation: ${\frac {\partial f}{\partial x}}$ Dominick ^(ŤαĿĶ) 23:37, 21 October 2005 (UTC)[reply]

You can borrow some notation from thermodynamics, (but is also used elsewhere). Suppose f = f(x,y,z). Then

\left({\frac {\partial f}{\partial x}}\right)_{y,z}

is the partial derivative of f taken with respect to x keeping y and z constant.

But in the context of this question, it seems that you want to define

\left({\frac {df}{dx}}\right)_{z}

and this generally does not really make much sense. You need some sort of transformation to rigorously define what you would like to do here. --HappyCamper 15:50, 22 October 2005 (UTC)[reply]

I have seen

{\frac {\partial f}{\partial x}}{\Bigg |}_{z}

but you are right, it is vague. I made it clear in text, but rarely it was an issue except at a boundry. Dominick ^(ŤαĿĶ) 14:43, 23 October 2005 (UTC)[reply]

Really? I didn't know that notation was in use too. That explains a few things now in another paper I was reading. I kept on thinking that it meant

{\frac {\partial f}{\partial x}}{\Bigg |}_{x=z}

, in other words, differentiate with respect to x, and then evaluate the result for x =z, which seemed to be highly redundant. --HappyCamper 14:55, 23 October 2005 (UTC)[reply]

Calculus is hard to express without good shared notation. Partial derivatives are done where more than one variable may change. They differ in from the "full" derivative only when a value is fixed. I would prefer to write

{\frac {\partial f}{\partial x}}{\Bigg |}_{z=0}

or

{\frac {\partial f}{\partial x}}{\Bigg |}_{z=1.23e4}

assuming f(x,y,z) still contains the y variable. The partial derivative will only get really different than a full derivative when I increase the order, for some reason writing,

{\frac {\partial ^{2}f}{\partial x\,\partial y}}

but thats a different headache. Dominick ^(ŤαĿĶ) 17:55, 23 October 2005 (UTC)[reply]

Thank you, guys, that settles the terminology and notation. (I will use Dominick's form for the fist equation with Pi_2 after explaining it somewhere). So what do you think about the second equation (with Pi_1)? To keep economy and game theory out of it - what they do is simply: Find the maximum by setting the derivative to 0 (and hoping that it isn't a minumum or saddle point). For this, they should use the total differential, so the current formula lacks a term, correct? (Maybe that discussion should be kept at Talk:Stackelberg competition#term missing.) Common Man 01:43, 24 October 2005 (UTC)[reply]

October 22

What are the bond angles of buckyball?

They are 120 and 108 degrees, aren't they?

Someone asked that earlier today. — File:Ontario trillium sig.pngmendel ☎ 20:41, 21 October 2005 (UTC)[reply]

No one answered it though, so are they 120 and 108 degree?

No, they must be less than 120°, otherwise you would have flat sheets as in graphite. Physchim62 12:18, 22 October 2005 (UTC)[reply]

Buckyballs (C₆₀) are made of pentagons and hexagons, exactly like a soccer ball. Presumably the bond angles in the hexagons are 120° and in the pentagons 108°. With each carbon being part of two hexagons and one pentagon, the sum of bond angles for each carbon is 348°, which is less than the 360° required for a flat sheet. —Ilmari Karonen 22:31, 24 October 2005 (UTC)[reply]

Peak busy hour

Generally, what is the percentage of total daily calls that occur during peak busy hour in a voice network?

What country are we talking about? - Mgm|^(talk) 08:26, 22 October 2005 (UTC)[reply]

PRODUCTION FUNTION CURVE ( URGENT)

WHY WE ARE PRODUCING PRODUCT AT THE POINT WHERE THE CURVE STARTS DECLINING?

PLEASE SEND ME THE ANSWER WITHIN 6 HRS OF MY QUERY, AS IT IS VERY IMPORTANT TOPIC FOR ME.......

Respectfully, ___ Muthukannan S. B.E, MBA MADURAI (INDIA)

If I understand the question, it falls into the general category of "why should a company produce additional units at a lower than optimal profit margin". There could be many reasons for this:

They want to maximize the amount of profit, not just the rate. While a 10% rate of return on a million dollars is better than a 9% return on a million, a 9% return on a two million may well be better than either, depending on your perspective. A single owner of a company would rather have the 180,000 profit that would generate than the 100,000 profit in the previous case.

The larger production may allow a greater market share, which will then lead to greater future profit amounts and rates.

They may have significant fixed costs which are better divided among many units than a few.

StuRat 20:46, 21 October 2005 (UTC)[reply]

Can you be a bit more specific who "we" is, and which product and which curve you refer to? WRT "Respectfully": Using all caps is regarded as shouting, which is not considered respectful. Nor is setting deadlines without explanation. Common Man 20:32, 21 October 2005 (UTC)[reply]

Is his homework due in six hours? TenOfAllTrades(talk) 20:37, 21 October 2005 (UTC)[reply]

It is because that is the point where marginal cost begins to exceed marginal benefit. - SimonP 20:41, 21 October 2005 (UTC)[reply]

space shuttle

what factors did the engineers consider when designing the tiles for the space shuttle?

This seems like a homework question, but I'll give you the benefit of the doubt. Ceramic tiles are able to withstand intense heat. They need not resist great (bending) forces, but they need to be able to cope with vibrations. Because of this, the tiles are connected to the main body of the shuttle via a dampening support frame. The tiles probably have variable thickness, too.

As the article states, that the original silica-based ceramic tiles need to be removed for inspection for damage after every flight, and they also soak up water and thus need to be protected from the rain. The latter problem was initially fixed by spraying the tiles with Scotchgard, but a custom solution was adopted. Later, many of the tiles on the cooler portions of the Shuttle were replaced by large blankets of insulating feltlike material, which means huge areas (notably the cargo bay area) no longer have to be inspected as often.

See Thermal Protection System. -- Ec5618 23:45, 21 October 2005 (UTC)[reply]

Apart from the reasons in the excellent response above, weight is a critical issue. Although they are ceramic, when I saw a TV scientist mucking around with an old Space Shuttle tile it seemed to have a density resembling foam rather than the tiles we have in our homes.--Commander Keane 00:16, 22 October 2005 (UTC)[reply]

Of course, they must not only withstand heat, but also act as effective insulators to prevent that heat from reaching the shuttle body. StuRat 02:26, 22 October 2005 (UTC)[reply]

AIDS

Is it that a person infected with AIDS will sure die ??

we can be sure that everyone dies in the end, with or without AIDS -01:47, 22 October 2005 (UTC)

Assuming you meant to say "...die from AIDS", then no, for several reasons:

Medications exist which seem to be able to prevent, indefinitely, death from AIDS. The "AIDS cocktail" seems to be effective, although very expensive. In some patients, they seem to develop a drug resistant strain of AIDS. This can be managed by changing the mix of medications, however, at least in the short term.

"Infected with AIDS" is rather vague. Some people are HIV positive, meaning they have been infected by the virus, but never show any symtoms of AIDS. These people appear to have a natural immunity. Interestingly, the same immunity from the bubonic plague also appears to offer immunity from AIDS.

Genetic engineering may offer a way to extend this immunity to all people within a few years. So, if someone with AIDS can survive until then, they may be cured.

StuRat 02:14, 22 October 2005 (UTC)[reply]

People don't get infected with AIDS, but with the HIV virus. When this happens they are HIV positive, but it may take many years before they even show the slightest sign of having AIDS. Some people never develop the symptoms and die of other causes. So while people do die in the end, AIDS may not neccesarily be the cause of their death. StuRat was right. There's drugs that slow down the disease allowing the infectee to have a fairly normal life without having to worry about dying, provided they do regular checkups with their doctor. - Mgm|^(talk) 08:31, 22 October 2005 (UTC)[reply]

Every human will surely die, regardless of whether they have AIDS or not. -Drdisque 16:28, 22 October 2005 (UTC)[reply]

Ask Magic Johnson. It seems HIV+ people with enough money can battle AIDS for a very long time. --Quasipalm 17:17, 22 October 2005 (UTC)[reply]

Also note that people with aids usually die because of so-called "opportunistic diseases". These diseases wouldn't normally kill a healthy person with proper access to healthcare, but are a serious danger to people who have developed AIDS. -- Rune Welsh | ταλκ | Esperanza 13:52, 23 October 2005 (UTC)[reply]

- You all forgot one reason: They might get run over by a bus or something. A tonne of steel moving at 80 kph doesn't discriminate between HIV-negative and -positive people. — JIP | Talk 16:27, 24 October 2005 (UTC)[reply]

Equation editor on Word

Is there a shortcut to get the equation editor on Word 2003? Or do you have to go to Insert>Object>Microsoft Equation Editor everytime? A way to get it on the toolbar would be handy. Thanks Akamad 07:04, 22 October 2005 (UTC)[reply]

No idea about Word 2003, but under older versions you could go to the Tools/Customize... menu, choose the "Commands" tab, then category "Insert", and scroll down to find an "Equation editor" button which you could drag to any toolbar. I suspect it should work the same way in new versions of Word. --Bob Mellish 07:19, 22 October 2005 (UTC)[reply]

Thanks kind sir :-) That works nicely. As it turns out you can also assign keyboard shortcuts from the same place, which is exactly what I wanted. Akamad 07:45, 22 October 2005 (UTC)[reply]

Hmmm...I added it both to my toolbar and assigned it a keyboard shortcut, but they are not there when I restart Word. Any ideas? Thanks :-) Akamad 09:05, 22 October 2005 (UTC)[reply]

Make sure that Word is saving the toolbar changes to Normal.dot, not just the current document. I know under Word XP there's a clear drop-down box which has the options of saving either to Normal.dot or just the current document. If you're getting to it the same way in Word 2003 (through the Tools/Customize menu), it should have it there as well.

That should work, but if you're sure it's saving to Normal.dot ("sure" as in you can clearly see the option is Normal.dot), then you can create a macro in Word which will automatically do anything. It's under Tools -> Macro -> Record New Macro. You can assign the shortcut to the macro to toolbars or keyboard, but either way, make sure it's saving the macro to Normal.dot. When you finish saving the macro settings, it will start recording the macro. Then get open the equation editor the way you usually do it, and stop recording the macro. Then you can use this macro later to instantly do what you just did. -- Daverocks 10:30, 22 October 2005 (UTC)[reply]

I think there is something wrong with my Normal.dot file, because anything I save to it seems to be gone when I re-open Word, I might try re-installing Office. Thanks for your help :-) Akamad 00:34, 23 October 2005 (UTC)[reply]

Toothpaste Vs Charcoal

I need to write an essay on Toothpaste, its history, the devolopment procedures of toothpaste (including any equations or formuals and why it was made) and any benifits to this compound. I also have to write the same information about charcoal and how it can be used as toothpaste and i need to write the positives and negatives side of using toothpaste instead of charcoal. As you can tell, I'm having no difficulties finding information about the toothpaste side, but i am finding it extremley hard to find some information abut the charcoal side. Any information about charcoal and toothpaste would be of great use to me.

Thank you

A google search for charcoal toothpaste [10] reveals pages like this: [11]. I'm not recommending that page in particular, but you could look around like that. Our article on toothpaste may help also. -- SCZenz 09:29, 22 October 2005 (UTC)[reply]

Thank you for your reply, but i am still in need for more information about charcoal. I have already looked up the sites that you advise me too see and managed to find some information about toothpaste but not charcoal. Again thankyou for your help and any information about charcoal would be of great use to me.

You might try asking on camping forums. When I was a Boy Scout I was told that in a pinch, chewing coals from a fire (which had cooled first of course) cleans teeth. Since I was told this on a camping expedition by someone who was instructing us on various ways to use nature I would think that someone on a camping forum may know more about using coals in this fashion. Dismas|^(talk) 15:57, 23 October 2005 (UTC)[reply]

Do wild animals snore?

I guess they don't. An animal that snores would always attract predators or alert preys. Such a genetical feature shall be eliminated by natural selection in no time.

I also don't think ancient humans and earlier hominids snored much. I guess snoring marks the rise of our undefeatable human civilization where men in bed are no longer eaten by big cats. As a result, bad genes are not eliminated and people start to snore. -- Toytoy 10:08, 22 October 2005 (UTC)[reply]

From the New York Times

Q. Do any animals besides people snore?
A. Yes, some animals do snore, according to anecdotal reports and personal observations, said Penny Calk, manager of the mammal collections of the Bronx Zoo.
"Some that we have observed are dogs, gorillas and bears," she said.
The mechanism of snoring in these mammals probably resembles what happens in people. In human beings, according to The American Medical Association Encyclopedia of Medicine (Random House), snoring is noisy breathing through the open mouth produced by vibration of the soft palate, the back part of the separation between the oral and nasal cavities. It is more common while people are sleeping on the back, as the lower jaw tends to drop open. Snoring is caused by anything that hinders breathing through the nose. Gnats

Evolution sometimes 'picks' traits that don't seem to make sense to us for a variety of reasons -- for example, they may be a side effect of some positive trait or may increase herd health overall. For example, you may think that sleep itself should also be eliminated by evolution at some point simply because laying about in the wild unconscious is certainly the easiest way to become lunch -- however, the positive impact of sleep probably makes it worth it. There are other examples, like take homosexual animals and humans, which seem to be in a number of populations, despite obvious limitations on reproduction. And of course, evolution isn't finished, and never will be finished, so that there are current 'issues' with current models is to be expected. ;-)

(You might point out that animals in the zoo don't face evolutionary pressures either, so that's why they snored, but I would assume that gorillas and bears have been captive for a small enough number of generations to not have evolved in any major way. Another thought: maybe if bears and humans and gorillas and dogs (former wolves) snore, it could be a sign that only the animals least prone to becoming the lunch of other predators have the evolutionary leeway to get away with snoring -- could be an interesting theory. "Origins of the snoring species." ) --Quasipalm 16:48, 22 October 2005 (UTC)[reply]

Dogs have been selected by human for thousands of years. Some dogs now look so unnatural that they cannot survive in the wild for a day. Since a dog breeds in a couple of years from birth, the evolution or devolution of its anti-snoring features can be several times faster than us humans.

Bears and gorillas are on the top of the food chain. Maybe they do not afraid to be eaten by all these lovely rabbits and hamsters at night. Maybe, I guess.

As to the majority of animals that are much smaller than humans, I guess they don't snore because their breathing is less of a problem. And as to the other ones much larger than us, maybe their soft palates are much thicker and vibrate at much much lower frequencies.

Do some bigger chimpanzees snore? Do some bigger orangutans snore?

Did these long-neck sauropod dinosaurs snore? Did the fattest T.rex snore? Survival the fattest! -- Toytoy 19:56, 22 October 2005 (UTC)[reply]

How do dogs recognize each other?

File:SW3vader.png

Sob! My dog will never recognize me again! George Lucas go to hell!

Dogs of different breed can be very different from each other. How does a Dalmatian recognize a Chihuahua?

Humans are not dogs. How does a dog recognize humans? A person can wear a red T-shirt today, a black tuxedo tomorrow. How does a dog (color blind) learn to disregard some but not all visual signals? How many house pets can recognize their owners if the clothing, smell (perfune) and facial features (shaved or not; hair cut; cosmetic makeup; eye glasses) changes? Can a guinea pig does that? Can David Prowse's dog recognize him if he wears the Darth Vader suit? -- Toytoy 10:53, 22 October 2005 (UTC)[reply]

Dogs recognize other dogs as dogs because they smell of dog. Smell is much more important than sight to a dog. Shantavira 16:12, 22 October 2005 (UTC)[reply]

Dogs have been selected by human for the past thousands of years. How did they manage to keep all these intercanine communication protocols? I mean you breed a new kind of dog based on its human usable features (look, ability to hunt, alertness ...). Maybe by some God-initiated accident, the best retriever in the world may smell like a cat! What a tragedy! I mean a dog that does not smell OK to the "Head Beagle" survives if it helps its owner make or save money. How can a dog intelligently designed in Yorkshire and another one intelligently designed in Beijing know each other? -- Toytoy 20:11, 22 October 2005 (UTC)[reply]

OK, a dog owned and bred by human still needs to have sex with another dog to beget puppies. Maybe this partially explains my question. If no other dog wants to have sex with your blue-ribbon retriever, you cannot breed it. No dog wants to have sex with your lousy gold medal. No way. They have to smell each other's anal gland so they can have sex.

What will happen if we perform artificial insemination on dogs? Will they lose the ability to recognize other dogs one day? -- Toytoy 20:25, 22 October 2005 (UTC)[reply]

If we eliminate the last threads of survival of the fittest, and instead cause all dogs to reproduce, this will eventually lead to degradation of the species to a level where they lose many abilities, including the abiity to smell. Purebred dogs already have many health problems, such as hip displasia, as a result of breeding. Salmon in fisheries were bred by the fish equivalent of artificial insemination (cutting them open to mix the eggs and milt) and suffered a rather alarming degradation of the species as a result. StuRat 20:58, 22 October 2005 (UTC)[reply]

I think basic reproductive functions will still be there. You still need to form good-enough sperms and eggs. And with mammalian animals, a female needs to have a working uterus even if you perform cesarean section in the end.

I always believe today's people have more inherited diseases than their ancestors. Maybe one day, many people will have degraded eyes and some other degraded complex organs. -- Toytoy 21:40, 22 October 2005 (UTC)[reply]

I heard some where that a dog can recognise more smells than we can recognise colours, for example, if two colours of red were so close we couldn't tell the difference, if those reds were smells, a dog could tell the difference.--Eye 19:23, 22 October 2005 (UTC)[reply]

I live on the 4th floor and my dog can notice my arrival at about the time I enter my apartment silently. Sound of footsteps can be a clue. I just don't know which senses they use and which ones they exclude. How do animals know a human changes clothing and makeup everyday so if one person's torso looks much darker than he/she was 2 minutes ago, that's still OK? I guess high intelligent social animals know their owners better.

Pets can learn, to some extent. The first time you came home wearing a bear suit, they likely would be rather frightened until they identified your voice and smell. However, the next time they would know that is within the range of clothing you wear. Pets also tend to think their image in a mirror is another animal, the first time they see it. After a while, they know better.StuRat 20:58, 22 October 2005 (UTC)[reply]

Do pets other than cats and dogs (hamster, chicken, snake, horse ...) recognize owners so well? -- Toytoy 19:39, 22 October 2005 (UTC)[reply]

Intelligent animals like a horse, pig, or parrot, yes. Stupid animals like a fish or chicken, no. StuRat 21:02, 22 October 2005 (UTC)[reply]

I think the "Human Recognition Algorithms" used by dolphins must be different from the ones used by dogs. Maybe a scientist can intelligently design a human dress code to fool 90% of dolphines, 10% of dogs and 100% of people and another to fool 10% of dolphins, 90% of dogs and still 100% of people. -- Toytoy 21:23, 22 October 2005 (UTC)[reply]

Most animals know who feeds them. A lady with long blonde hair feeds red kites in Wales. The only other people who can feed them are people with long blonde hair, (or blonde wigs)--Eye 20:06, 22 October 2005 (UTC)[reply]

To my original suggestion I would add that instinct is a very strong motivation, probably the only motivation in lower animals. When a dog sees anything trotting down the street on four legs its instinct is to investigate to see if it can have sex with it, chase it, sniff it, fight it, or play with it. It probably doesn't have a concept of "dog" but responds to it instinctually according its reaction to its smell and behaviour. Also dogs tend not to be too fussy what they have sex with. A dog is clearly shown "shagging the cat" in one episode of The Osbournes. Shantavira 10:15, 23 October 2005 (UTC)[reply]

I was always curious about a similar question -- how do humans recognize one golden retriever out of many golden retrievers? :-) --I am not good at running 18:17, 29 October 2005 (UTC)[reply]

Windows XP log on screen

Ages ago when I was messing around with the computer at my parents' house trying to do something that doesn't need going into here, I somehow lumbered it with starting up with the Windows XP network long-on screen every time it boots up, even though the computer isn't connected to a network. There's no password set so it can be quickly gotten rid of my hitting the enter key, but it's still an irritant, and for the life me me I can't work out how to get rid of it. I've tried all sorts of things in the control panel and so forth, and Windows online help is sod all use. Can anybody help with this one? I'd be much obliged if so. Angmering 10:47, 22 October 2005 (UTC)[reply]

Maybe turn on the "Welcome" screen under User accounts? I don't know if you can do that under XP Professional, but you definitely can on Home Edition. Although I suppose it would still require you to click the name on the Welcome screen to get on to the computer. You could try reinstalling Windows XP, but maybe you should try get some other help before doing that. I don't know an exact way to get rid of it, but there must be some value in the Registry that toggles on and off automatic logon. Does anyone know that? Alternatively, use a Linux distro as your operating system instead. -- Daverocks 12:42, 22 October 2005 (UTC)[reply]

Help identifying frog photo

This morning, I saw a frog on one of my sliding glass windows. I took a bunch of pictures of it. Can anyone help me identify which frog breed it was so I can upload the batch to the Commons? This picture was taken in south Florida (north Palm Beach County). Neutrality^talk 15:31, 22 October 2005 (UTC)[reply]

Green Treefrog [12] (hyla cinerea) according to the UF website [13]. Dominick ^(ŤαĿĶ) 15:39, 22 October 2005 (UTC)[reply]

Thanks! Neutrality^talk 16:03, 22 October 2005 (UTC)[reply]

I wish I lived in a place where I could see such a creature on my window. :-( --Eye 16:54, 22 October 2005 (UTC)[reply]

Frog, Part II

OK, I wrote an article on American green tree frog. Two requests:

First, can someone tell me the full name of "Schneider," who apparently first described and classified the species in 1792?
Second, can somebody fix the taxobox in the article? Something messed up and now the entire article is in the taxobox!

--Neutrality^talk 18:49, 22 October 2005 (UTC)[reply]

Fixed. He was Johann Gottlob Schneider. Gdr 19:21, 22 October 2005 (UTC)[reply]

Nice job! Dominick ^(ŤαĿĶ) 14:45, 23 October 2005 (UTC)[reply]

Thanks, Gdr! Neutrality^talk 21:20, 23 October 2005 (UTC)[reply]

Saliva Spray

Does anyone know what it's called when saliva sprays from underneath your tongue toward the back of your mouth? I've never heard of this spoken of, but have experienced it, as has at least one other member of my family. Theshibboleth 16:29, 22 October 2005 (UTC)[reply]

In America, this can be called "gleeking" or "gleek." [14] It may be called something else too, and I'm not sure if it's slang. I suppose the formal way of saying it might just be "salivate," or "projectile salivation." ;-) --Quasipalm 17:05, 22 October 2005 (UTC)[reply]

I wonder if there's a photo in the commons of someone doing a saliva spray.--Commander Keane 17:21, 22 October 2005 (UTC)[reply]

I have seen such a photo. It was published around 1972 in an anatomy text for medical students (Becker maybe?). Unfortunately not something we can use here. alteripse 04:28, 23 October 2005 (UTC)[reply]

To my knowledge, there is no formal word to designate the forceful ejection of saliva from under the tongue (I cannot exclude the possibility that a slang word exists). The phenomenon results from the compression of the ducts of the sublingual and the submandibular salivary glands by the muscles of the floor of the mouth, such as the mylohyoid, the digastric and the genioglossus, which cause a rapid expulsion of the ductal contents. By the way, the saliva is usually projected forward and upward, rather than toward the back of the mouth. I have been sprayed by my patients in this way on several occasions... --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 18:29, 28 October 2005 (UTC)

Nicotine

For years, I've been told that nicotine can stunt the body's growth. Is this a fact? Thanks, Dave.

I'm not actually sure, however, nicotine and smoking do cause bloodvessels to narrow, inhibiting the supply of blood throughout the body. This can certainly cause problems with growth, though that would hardly be the most pronounced effect on the body. -- Ec5618 17:44, 22 October 2005 (UTC)[reply]

I suppose it could retard your production of NAD+ and thus might have some effect on lipidbiosynthesis, and hormone regulation, but then I don't know how your body deals with pure nicotine--4.237.23.16 18:19, 22 October 2005 (UTC)[reply]

Elementary biochemistry error here. The problem with this speculation is that it forgets the difference between signal effects and metabolite effects. Nicotine is a signal molecule, like hormones and neurotransmitters. All of its effects result from this and the needed amount for this type of effect is tiny. On the other hand, for a metabolite to competitively interfere with a basic metabolic process that occurs in multiple forms in most cell systems, requires order of magnitude higher tissue concentrations (far more than can be delivered by your basic nicotine delivery device). The names should not be so similar because it tempts the novice into this confusion. Furthermore, a large proportion of the adverse effects of smoking are not attributable to the nicotine-- the nicotine is just the reward that perpetuates the addiction but is only a small fraction of the substances ingested. alteripse 15:24, 23 October 2005 (UTC)[reply]

Cigarette smoking can stunt your growth if your mother does it, before or after you are born. The evidence for mild prenatal stunting is strong, the evidence for postnatal (i.e., secondhand smoke effects) weaker. Unless you are idiot enough to turn mild asthma into severe by heavy smoking in early teens, your own smoking won't affect the last couple of years of remaining growth. Although most smokers start as children, most of the adverse systemic effects that might interfere with growth take several years to accumulate.alteripse 04:30, 23 October 2005 (UTC)[reply]

T-Rex

In the article on Tyrannosaurus rex, I'd like to include the number of T-rex fossils (incomplete or otherwise) ever found. Does anyone have a reputable, current source? -- Ec5618 18:10, 22 October 2005 (UTC)[reply]

Maybe you could visit your local university and check out paleontology journals, like The Paleontological Society and JOURNAL OF DINOSAUR PALEONTOLOGY. You may also find access to some of them online. --Quasipalm 01:11, 23 October 2005 (UTC)[reply]

Museum Victoria says "there are now parts of more than twenty-one individuals known from western USA". T. rex fossils are also found in Canada; National Geographic magazine comments on "the wealth of T. rex fossils already found—more than 30 to date". Gdr 09:51, 23 October 2005 (UTC)[reply]

Good to the Last Drop? or is it?

Is maxwell house coffee considered instant coffee, or just bad coffee?--4.237.23.16 18:21, 22 October 2005 (UTC)[reply]

It is one of several brands of instant coffee, a beverage derived from, but really quite different from, coffee. Plenty of people buy it, so it can't be that bad. Not to my taste though. Shantavira 18:27, 22 October 2005 (UTC)[reply]

Maxwell House makes both instant and regular coffee: [15] — File:Ontario trillium sig.pngmendel ☎ 05:45, 23 October 2005 (UTC)[reply]

You'll never get the answer to the question "Is MH considered .. bad coffee" here or anywhere else. There is no answer that would satisfy everybody, and there is no final arbiter of the truth when it comes to personal taste. If a person doesn't like it, the only truthful statement about that circumstance is "He doesn't like it". JackofOz 11:46, 23 October 2005 (UTC)[reply]

How calculators work

I was wondering if someone could explain to me how calculators work. I have looked all over the internet and I can't find anything. The Wikipedia article on calculators doesn't explain how they work, and its not on howstuffworks.com. Madsci.org has a page about it but it's written for a child and not very detailed. Thanks. --Taylor

It rather depends on what level you want it described. Nowadays, the simple type of calculator is a small, dedicated computer, with no external RAM, just a dedicated CPU (a simple one, nothing much more than an ALU), probably a built-in ROM containing its control program, and an interface to the display and keypad. (More complex calculators with programmability etc., will have external RAM and are in effect small general-purpose computers). If you read up on how a CPU works, that will cover just about everything. In the past, calculators were probably made from digital logic chips, but CPUs are so cheap now I doubt that's cost effective. --Bob Mellish 19:57, 22 October 2005 (UTC)[reply]

What are the differences between a $0.75-cheap solar-powered giveaway calculator and a low-end engineer calculator today? Do they use the same core chip? I guess it could be cost-efficient to manufacture a general-purpose calculator chip based on 6502 or Z80 than to manufacture two or more.

Does a dirt-cheap calculator use a floating point-based number format internally? Or does it use fixed-point arithmetic? Do they follow IEEE standards (e.g. IEEE floating-point standard)? Maybe not, I guess. These old CPUs only have integer ALUs (+ and - only). So you write your own floating- or fixed-point programs with or without following standards. -- Toytoy 21:02, 22 October 2005 (UTC)[reply]

A common project used to be design an ASMD calculator, where the student would create the spec, and some of the logic. IIRC, the math details were not specified as part of the project. In any calculator, the implementation varies, and it can be anything from a processor, to a FPGA or a PLD. I usually use a simple test to evaluate designs, many fail this test, including the MS windows calculator in basic mode. Type 1+2*3 the correct answer is 7 if the calculator uses order of operations correctly, the incorrect answer is 9, this means the calculator evaluated (1+2)*3. Most calculators don't tell you the internal float format, and you shouldn't care. If you really need to know, like for astronomical calculation, then you should not be using a pocket calculator. Dominick ^(ŤαĿĶ) 11:38, 23 October 2005 (UTC)[reply]

I guess if you want to mass produce something cheaply, you will not use FPGA or PLD, will you? There must be some widely used generic calculator chips. -- Toytoy 16:20, 23 October 2005 (UTC)[reply]

Kangaroos

Do male kangaroos have pouches or is it just the females? If so why?

This is like the "men's nipples" question that has been discussed recently. A pouch is more costly than nipples on a male kangaroo. But if without it on a female kangaroo, it will be a disaster. I don't own a male kangaroo so I cannot answer your question directly. But I guess the answer is yes. As you know, animals were designed by an intelligent but inexperienced designer who did not spend a couple of minutes to undesign men's nipples and male kangaroos' pouches. God, someone please teach that lousy designer a biological lesson! -- Toytoy 21:10, 22 October 2005 (UTC)[reply]

A pouch on a male kangaroo would be a disaster as well because they rip at each others bellies when they fight. Is there an aussi amongst us who could settle the question?--Eye 21:25, 22 October 2005 (UTC)[reply]

Who needs an aussie when you've got an encyclopedia? Our article on marsupials begins, "Marsupials are mammals in which the female typically has a pouch." (Boy, it's hard to read articles on marsupial or monotreme reproduction without wondering if the articles have been vandalized. Strange critters.) Of course the trivial answer to why only the females have pouches is "because that's how they evolved", but it might help to note that the primary sexual characteristics of mammals tend to be unique to one sex. — File:Ontario trillium sig.pngmendel ☎ 05:36, 23 October 2005 (UTC)[reply]

Pages per Minute

When a printer says '15 pages per minute' or whatever, what is it printing? Certainly, I can never get more than 7 pages of normal quality text or 1 or 2 pages of photos from a printer in that time. smurrayinchester^{(User), (Talk)} 20:57, 22 October 2005 (UTC) [reply]

I once read that the PPM measurement is based on a 10% page coverage. It might have been 15% or 20% or even 5% - I can't remember the exact figure - but it's a ridiculously small amount, particularly when dealing with photos. --Pidgeot (t) (c) (e) 00:43, 23 October 2005 (UTC)[reply]

When they state "X PPM", look for the fine print elsewhere on the page that specifies the conditions under which the test was conducted :)--inks ^T 04:02, 23 October 2005 (UTC)[reply]

Such figures are indeed usually about printing pages with a low coverage (meaning the percentage of the page that gets ink on it) - 10% would be text with plenty of open lines. And it will also normally refer to the fastest printing option with low quality. 4 seconds per page doesn't sound too strange for a modern printer. Mine approaches that. The problem with these figures is that they're only about one little aspect and between printers it's not even standardised, so they don't even serve for a comparison. Best ignore them. It's just the company showing off with useless info. DirkvdM 18:52, 24 October 2005 (UTC)[reply]

October 23

Recent Mergers

I would like to know a large merger that happened in the last 6 months. I mean a really big merger between two well-known companies. If it made news in the NY Times or a large newsource, that would be good. The reason is simple: there aren't any. I can think of plenty of large car company hybrids, but no large mergers between banks, auto companies, anything these days. Name one and I'd be happy to read it.

Symantec merged with Veritas, in the single largest merger of software companies to date. The original intention to merge was announced in December 2004, but the actual merger took place in July 2005, after regulatory approval. See List of Symantec acquisitions.-gadfium 03:59, 23 October 2005 (UTC)[reply]

US Airways acquired America West Airlines -Drdisque 03:58, 23 October 2005 (UTC)[reply]

To be honest, I only wanted to answer my homework. It's a shame I didn't get more answers though. Let this be a lesson. If you want homework answers, ask for them well.00:18, 26 October 2005 (UTC)

Why?

I reformatted by computer, now for some reason my computer no longer has the right codec to play .WMV files?? How can this happen? Shouldn't the one codec a clean restore leaves you with be the windows media format?! I mean, isn't that odd? how can I get it back?Thank you for helping me--help me 03:51, 23 October 2005 (UTC)

Even some types of .WMV files need external codecs to play. Before you formatted, you may have had the popular ffdshow codec. If installing that doesn't solve your problem, try using DivX. However, it's more likely that ffdshow will solve your problem. -- Daverocks 08:46, 23 October 2005 (UTC)[reply]

I would suggest downloading VLC media player -- it's built with a ton of codecs built into the system so you don't have to worry about not having the right one or downloading new ones. --Quasipalm 14:19, 23 October 2005 (UTC)[reply]

I second Daverocks. To elaborate on his comment: Just like for an .AVI file or a QuickTime file, a .WMV file may have been encoded with any video codec. The fact that it has a .WMV suffix doesn't necessarily mean it was encoded with any particular codec. Some mad scientist at Intel may be encoding video right now with an exotic codec he wrote himself, and the files he's generating are .WMV files. Then embedded within the .WMV file, there's an indication of which video codec was used. When you do a regular install of Windows Media Player, you get a collection of codecs that Microsoft wrote or has licensed, but some other popular codecs are not included, most notably Divx. Tempshill 03:00, 24 October 2005 (UTC)[reply]

Why do women wants unproportional breasts?

I am puzzled, why some women like to enlarge their breasts so big that it looks unproportional? I think natural is better.

As a counter-balance to their huge, Jennifer Lopez butts they got from the last surgery ? StuRat 18:27, 30 October 2005 (UTC)[reply]

It's a cultural thing, particularly in the United States. I think it might be less common than it was a decade ago. See Breast implant#Risks_and_controversy.-gadfium 05:09, 23 October 2005 (UTC)[reply]

A few years ago I heard that plastic surgery in the USA is usually enlargement, whereas in France it's usually to make them smaller, so that would indeed make it a cultural thing. I also suppose it's about what women think men want and that might be influenced by porn movies and such, which represent fantasies that men would not want to encounter in real life. Or maybe the movie makers get it wrong too, leaving the men with little choice. DirkvdM 19:05, 24 October 2005 (UTC)[reply]

I'm somewhat dubious about the claims that breast surgery in France is for making them smaller, though I think that breast implants are less popular in France than in the US. David.Monniaux 18:14, 30 October 2005 (UTC)[reply]

XXXXXXXXXXXXXXXXXXXXXXXXXL-sized breasts is a small but existent market. If you want to please ordinary people, you need a B-cup, C-cup or, at most, an E-cup. Most of us has a taste of regular-sized breasts. An A-cup is not a bad idea even if you work for the adult entertainment industry. Many people enjoy A-cups. However, there are some people whose taste of breasts cannot be satisfied with any sized breasts. They ask for breasts of unlimited sizes. That's probably why some porn stars began their unnatural and unhealthy boobs arms race.

Not only some men are crazy for over-sized breasts, some women are too. It's like having the biggest, baddest and loudest car of this planet. People really don't need it but some people do want it badly. I guess when a porn star gets a boost in her boobs, many other porn stars sharing the same niche want to upgrade theirs too because they need to please the few customers. However, I loath to see these porns so I cannot give you a real world example other than this generalized theoretical analysis. I can be dead wrong. The truth can be more interesting.

By the way, I have seen a Japanese web clip that displays breasts from A-cup to Z-cup to the tune of the Alphabet song: "A, B, C, D, E, F, G, ..." That's @#$%ing crazy. -- Toytoy 12:45, 25 October 2005 (UTC)[reply]

I notice we have a Human penis size article but not a Human breast size article! Who wants to volunteer to attempt collecting images? -- Chuq 04:02, 30 October 2005 (UTC)[reply]

"Women who are so concerned about their small breast size that they end up having surgery are just making mountains out of mole-hills." - Three's Company StuRat 18:27, 30 October 2005 (UTC)[reply]

How do male kangaroos urinate?

From marsupial:

Males usually have a two-pronged penis which corresponds to the females' two vaginas.

I don't think there are too many Aussie porn movies created for their marsupian population. How do these animals piss?

I really don't know anything about these strange creatures. Just 10 minutes ago, I thought Joey is a man who sells hot dogs at a street corner. -- Toytoy 05:54, 23 October 2005 (UTC)[reply]

Twice as efficiently? I guess "aim" is not important to a kangaroo. However "two-pronged" is a little suspect. Please see these delightful pictures of single-pronged kangaroo penises. Shantavira 10:44, 23 October 2005 (UTC)[reply]

Great pics! Do we have an article on kangaroo penis to put them in? alteripse 15:16, 23 October 2005 (UTC)[reply]

Marsupials have a cloaca [16] [17] that is connected to a urogenital sac in both sexes. Waste is stored there before expulsion. Urine does not exit through the forked penis. Dominick ^(ŤαĿĶ) 20:15, 23 October 2005 (UTC)[reply]

Quantifying universal indicator paper.

Does anybody know if you can quantify the use of universal indicator paper. I have thought about putting the paper through a spectrophotometer to get a quantitive result; but is this the best way to go about quantifying this data. I have also considered the use of a pH meter but dismissed this route.

If possible, use a pH meter. It's easier.

Otherwise, you may want to use a drop of Universal Indicator without the paper part. If you cannot buy it, prepare it by yourself. It's more difficult to obtain a good reading from light reflected from paper. You can take the absorption spectrum of that drop of indicator. You also need to calibrate your system. Personally, I think calibration is a difficult job because external factors such as temperature and other impurities can affect the color of that drop of indicator. -- Toytoy 10:32, 23 October 2005 (UTC)[reply]

Exactly. The whole point of indicator paper is just to give you an approximation of the pH of a solution. If you need anything accurate a pH meter is the way to go. -- Rune Welsh | ταλκ | Esperanza 13:33, 23 October 2005 (UTC)[reply]

*shudder* - there are things much, much, much better than pH meters - the fact that you mentioned a spectrophotometer makes me wonder whether this is for a paper or such? How accurate do you need the result to be? --HappyCamper 14:52, 23 October 2005 (UTC)[reply]

In answer to the above question from "Happy Camper" I just need a way of quantifing my results from Universal indicator paper. Will the spectrophotometer work with just the paper.?? By reflecting the light or something to that extent off the paper.

Ah, I see what you are looking for. Well, check out spectrophotometer and analytical chemistry. From the first article, it says "Perhaps the most common application of spectrophotometers is the measurement of light absorption, but they can be designed to measure diffuse or specular reflectance." Hmm...I wonder...If you use one of these machines, would you mind taking a picture of it and donating it to Wikipedia, provided that it is compliant with the GFDL? :-) --HappyCamper 00:12, 24 October 2005 (UTC)[reply]

I think if you work for a paint company you need to measure diffuse or specular reflectance everyday. -- Toytoy 14:04, 24 October 2005 (UTC)[reply]

Street lamps' color

Why are street lights generally orange colored? I've heard that they increase visibility, are cheaper to produce, and that they attract fewer bugs -- but I have no idea which of these are true (if any). --Quasipalm 15:26, 23 October 2005 (UTC)[reply]

I think it might have more to do with running (electricity) costs rather than detracting bugs. In the Sodium vapor section of the History of street lighting in the United States article, it says that the sodium vapor lamps use the least amount of power compared ot other types. Street light also has a bit of info. --Commander Keane 15:53, 23 October 2005 (UTC)[reply]

Just in case you don't know, the color of street lamps is based on the gas contained within the lamps. They aren't intentionally colored with colored glass, if that's what you were thinking. StuRat 17:41, 23 October 2005 (UTC)[reply]

Last time I visit Los Angeles, I found they don't switch off street lamps at noon! (Outside the LAX airport.) If they only switch on lamps when it's dark, it'll save some money. -- Toytoy 16:24, 23 October 2005 (UTC)[reply]

Some lights are on timers and others are on photoelectric cells that turn them on when it gets dark. Both systems can fail, however, and I suspect that's what happened in LA-X. StuRat 17:41, 23 October 2005 (UTC)[reply]

The chief (and probably only) virtue of sodium vapor lights is the energy efficiency. They actually create problems with visibility due to the unnatural color; our eyes are evolved to work best with white light, as from the sun. Because of this, there is a movement now toward metal halide lamps.--Pharos 18:18, 23 October 2005 (UTC)[reply]

Several yeras ago, many cities on Southern California went around covering every other street lamp on every street with black plastic, so the sensors didn't detect that it was becoming night, and turn on. The idea was to reduce the cost of running all of the lamps every night. But through the years, the black plastic has deteriorated and now hangs in shreds and all of the lights come in at night anyway. I always wondered why covering the sensors with black plastic didn't make the sensors think it was perpetual night, and cause them to burn all the time, but apparently it didn't. User:Zoe|^(talk) 20:49, 23 October 2005 (UTC)[reply]

Agree with Pharos -- the yellow streetlamps are sodium lamps, chosen for their efficiency, in places where you don't need to recognise colours. I seem to recall using a sodium lamp in a high-school physics experiment for something, presumably because it transmits only a narrow band of that yellow colour (when it's warmed up; they're pink/red when cold) Ojw 22:01, 23 October 2005 (UTC)[reply]

I remember one time I had gone to a concert in San Francisco with some friends, and had parked in a parking garage. It was late at night when the show ended. We went to go find my car. We walked around the garage several times without finding the car, and for a while we were afraid it had been stolen… But who would steal a cheap Suzuki Swift? Eventually, we found it, and also why we had trouble noticing it before; the fiercely orange light of the parking garage was making my red car look purple! Garrett Albright 04:09, 24 October 2005 (UTC)[reply]

What is food transfer?

Well, it's the transfer of food between two places. A quick googling shows that food transfer is used as a term in the food and beverage industry for "food transfer equipment" (such as tubing for beverages) and also in the term "regurgitative food transfer" about how some animals vomit food to share it with other animals in their herd. --Quasipalm 18:12, 23 October 2005 (UTC)[reply]

Settle a bet - about a freezer

In the long run, is it more energy efficient to keep a freezer empty or full? Jooler 20:17, 23 October 2005 (UTC)[reply]

If you were to never open it, there would be no difference, since the flow of heat into the freeser depends only on the difference of temperatures between the inside and the outside, the surface area of the freezer, and its thermal conductivity. However, if you were to open it, I'd say that an empty freezer would have more of the cold air inside replaced with warm air than the full freezer, so the extra warm air would need to be cooled down. The warm air in the empty freezer would have negligible thermal capacitance relative to the walls, and the heat loss would be unaffected. The cooling of this extra air would require energy, so the full freezer would have a slightly lower consumption of energy and thus be more "efficient" (as in usage of energy per unit of time). --Borbrav 21:30, 23 October 2005 (UTC)[reply]

I disagree. If you have a lot of stuff in your freezer, once it all warms up it'll take a lot more energy to cool it because it has a lot more mass. -- SCZenz 21:36, 23 October 2005 (UTC)[reply]

But then you don't normally keep your freezer open for the time it takes to cool down the actual items in the freezer. --Borbrav 21:41, 23 October 2005 (UTC)[reply]

I suppose the heat capacity of the air is negligible to that of any solid item in the freezer. Also, to just halve the amount of air you'd really have to stuff the freezer (if you still want to be able to access anything in a practical way). So the amount of air seems irrelevant. And I can't think of another factor off hand, so I'd say there's no difference worth mentioning. DirkvdM 19:17, 24 October 2005 (UTC)[reply]

In the very long run, much of your foods exposed to air will oxidize. As a result, a full refrigerator will be less energy efficient. However, it is totally unworthy to keep an empty freezer running. So if you count the benefit to people, an empty but running freezer is a waste no matter how high the energy efficiency is. -- Toytoy 14:23, 25 October 2005 (UTC)[reply]

Neodymium ions

Are there any ions in neodymium if so what is its most common? Thank You Dennis S

Have you looked at our Neodymium article? -- SCZenz 20:14, 23 October 2005 (UTC)[reply]

Info on boron

I am doing a paper on Boron for humans. Would like an y relevent info. Joe Cambell

Boron as trace element for human diet? As a therapeutic agent? As a useful element for making things for humans? alteripse 21:21, 23 October 2005 (UTC)[reply]

Try Boron. Dominick ^(ŤαĿĶ) 21:24, 23 October 2005 (UTC)[reply]

See Boron#Applications and Boron#Precautions. Neutrality^talk 21:32, 23 October 2005 (UTC)[reply]

Is it the paper or the Boron that is intended for human consumption? DJ Clayworth 20:23, 25 October 2005 (UTC)[reply]

Help identifying bird and plant species

Unknown bird species

Unknown gladiolus species

Can somebody help identify this bird and gladiolus? And, if possible, it would be great if someone could touch up the photos (all I have is lousy Picasa). Neutrality^talk 21:31, 23 October 2005 (UTC)[reply]

Sandhill Crane (Grus canadensis) [18] Dominick ^(ŤαĿĶ) 21:43, 23 October 2005 (UTC)[reply]

Isn't that a common Bougainvillea? Dominick ^(ŤαĿĶ) 21:45, 23 October 2005 (UTC)[reply]

Oh, yes....you're quite right, I meant to say bougainvillea. Guess I'm not much of a botanist. ;) Neutrality^talk 21:48, 23 October 2005 (UTC)[reply]

Interesting distribution [19] IMHO, they are making a real presense in Florida. In the Ocala forest they are thick as thieves. They are also non-migratory[20]. Dominick ^(ŤαĿĶ) 23:18, 23 October 2005 (UTC)[reply]

October 24

alcohol

To what extent does alcohol cause brain damage?

Have a look at the article Effects of alcohol on the body. -- Canley 01:39, 24 October 2005 (UTC)[reply]

reproductive organ

is it true that if you dont use it you will lose it--65.175.226.190 23:40, 23 October 2005 (UTC)[reply]

Wikipedia does not give medical advice →Raul654 23:41, 23 October 2005 (UTC)[reply]

Unscientifically, no organs have ever fallen off for disuse. People in general, never lose organs, unless they are detached in trama. Dominick ^(ŤαĿĶ) 00:02, 24 October 2005 (UTC)[reply]

I don't want to upset our inquirer, but haven't you ever heard of disuse atrophy? alteripse 01:25, 24 October 2005 (UTC)[reply]

Am I supposed to know what this is about? Maybe I haven't watched enough US adolescent movies :) . DirkvdM 19:22, 24 October 2005 (UTC)[reply]

Some would say that watching one is too many. :-) Dismas|^(talk) 07:49, 25 October 2005 (UTC)[reply]

Well, just to be sure, masturbate a lot and keep yourself covered :) ☢ Ҡieff⌇↯ 12:36, 25 October 2005 (UTC)[reply]

i think that is the answer he was hoping on. :) Boneyard 10:26, 26 October 2005 (UTC)[reply]

bases/acids to catalase

what will happen if bases/acids are added to catalase-containing materials? What will happen if hydrogen peroxide is next added?--172.199.133.7 04:24, 24 October 2005 (UTC)[reply]

In order to help you with your homework, I suggest you read the article on catalase as well as Base (chemistry) and Acid. Dismas|^(talk) 05:14, 24 October 2005 (UTC)[reply]

Making an unfair die fair

To make an unfair coin fair, one can use the following trick

If a coin is bias then it cannot be used as a fair coin. But if the rules of the game is changed to properly rely on when the coin gives a certain result, the coin can still be used to produce a fair result. John von Neumann gave the following procedure :

  1. Toss the coin twice. Note down the first "result" and the second "result".
  2. If the results match, start over, forgetting both results.
  3. If the results differ, use the first result, forgetting the second.

Note: This procedure only works if the tosses are paired properly. If part of a pair is reused in another pair, the fairness may be ruined.

My question is this:

Is there a way to make an unfair dice fair? Ohanian 06:16, 24 October 2005 (UTC)[reply]

The equivalent procedure, for an N-sided die, would be:

Roll the die N times; note each result.
If any of the results match, start over, forgetting previous rolls.
If all the die rolls are different, use the first result and forget the rest.

Obviously this is a very inefficient procedure. -- SCZenz 06:28, 24 October 2005 (UTC)[reply]

I'm impressed by this procedure. If I ever play dice with the devil, I'll insist on these rules.-gadfium 07:51, 24 October 2005 (UTC)[reply]

If I were the devil, I'll give you a die or a coin that's so unfair that it will never give you anything other than head or 1. Analysis:

Possibility of H-H pair: 1*1=1
Possibility of H-T pair: 1*0=0
Possibility of T-H pair: 0*1=0
Possibility of T-T pair: 0*0=0

(Proof for the die follows the same logic.)

You lose. I win. I am evil. Who cares about you? Don't think you can outsmart devil. -- Toytoy 13:54, 24 October 2005 (UTC)[reply]

Actually the devil never wins either because no valid results are ever generated. So it's down to who dies of bordeom first (not that that's very helpful, I guess). DJ Clayworth 20:21, 25 October 2005 (UTC)[reply]

Its actually called a die (singular) or dice (plural). This method would help to make an unfair die fair. -- Ec5618 08:00, 24 October 2005 (UTC)[reply]

Polya Frequency Distribution

I am trying to find details for the Polya Frequency distribution. They are referred to as PF_infinity, PF_2, etc. From what I recall they are some kind of limit or not a limit of the sum of exponentials. I can't find them on Wikipedia, or Google.

The bigger problem is that I need the sum of 2 independent exponentials with different parameters.

Regrds, Abhijit Roy

Give this link a click at Wolfram Research

GFP

I need some information on the concerns regarding the effect GFP tags have on the behaviour of proteins, but searching for "concerns" "GFP-tagged protein" on Pubmed and Clusty only gets me experiments and papers where they were used.

Has anyone got an idea on how to refine my search, or can someone point me to a good resource on the subject. I've got the basic issues down, but I'd like to be more thourough. - 131.211.210.17 09:27, 24 October 2005 (UTC)[reply]

Don't use "concerns" in a scientific literature search. It is a reflection of your state of mind or valuation of something but the gap between denotative meaning and common connotative usage is too large to be a useful coding term. If you are concerned about actual risks, then search for "risk" as a term. If your concern is whether use distorts the function it is being used to measure, search for a general review of GFPs and scan for one from a methodology journal, and you should find a discussion of the issue. If neither of those is your "concern", I can't even guess and you will need to spell it out more plainly for us. alteripse 11:32, 24 October 2005 (UTC)[reply]

That question was me. I was looking for iterature that discusses the effect the tagging has on the function of the proteins that are being studied. - Mgm|^(talk) 17:59, 24 October 2005 (UTC)[reply]

I don't know much about this particular method but would start by looking for some review articles about the method itself to see if there is a discussion of your question, which now makes sense to me: If you tag a protein to observe it, does that change the behavior of the protein in an important way? Sounds like a good question. I assume that early work on the method compared the results obtained by GFP tagging with results obtained by other methods. Have you looked at any of the more recent volumes of Methods in Enzymology if you can't find anything online? As a last resort, call or email someone who has written one of the reviews and ask if they know of any examples in which the method gave misleading results because the tagging interfered with the protein. alteripse 20:59, 24 October 2005 (UTC)[reply]

I'll try if it works without another query. I need to have things as general as I can get them. Methods of Enzymology might work. Thanks for the ideas. - 131.211.210.17 07:49, 25 October 2005 (UTC)[reply]

Chemistry

why is the valence of alkali metals always 1?

The reason for this is because those elements have a single electron in their outer shell. When this electron is removed by a chemical reaction with an electron deficient element (like Chlorine) the element is more stable because the inner shell is filled.

Gas collection mechanism

First thanks for answering my earlier question on sun & planets gear & epicyclic gearing. This one is rather more theoretical. Is there at present any sort of semi-permeable material which would allow specific gasses (such as CO2 & Ozone) through into a balloon or other container but not let them out again. Would it be able to do this at normal pressure & therefore collect CO2 directly from the atmosphere, through some sort of osmosis or would some sort of pump be required to pump in air to the balloon & pump out all the air less the CO2. My reason for asking is that I had the thought of collecting CO2 in massive dirigibles/balloons & towing them to Mars to start off an atmosphere there. I also thought of taking gasses such as Ozone from a gas giant such as Neptune & towing them to earth to fill the hole over Antartica. I know we don't have the rocketry technology to do this right now but can we do the gas capture with current (or expected) technology? AllanHainey 13:56, 24 October 2005 (UTC)[reply]

Osmosis (which is just a special case of diffusion) only takes place from areas of high concentration to areas of low concentration. If you tried to construct such a balloon that was permeable only to carbon dioxide, you'd find that the diffusion would stop as soon as the concentration of CO₂ reached the same level as the outside air (i.e. thermodynamic equilibrium). That's not to say it can't be done, however, but it would require some kind of energy input—for example, continuously removing out the CO₂ to keep the diffusion going.

On the other hand, I believe other methods of gas separation are more commonly used and efficient. The standard method I learned in chemistry class uses refrigeration fractional distillation to separate the gases out according to their different boiling points. As for your idea about the ozone layer: the hole in the ozone layer is primarily caused by compounds like chlorofluorocarbons that break down ozone. If those chemicals are removed from the atmosphere, the ozone is naturally regenerated by ultraviolet light. Until that occurs, any other measures taken will probably be relatively ineffective. --David Wahler (talk) 17:04, 24 October 2005 (UTC)[reply]

You;d need one hell of a lot of CO2 to make a dent. Actually, if you'd construct rockets that produce CO2 as a waste product to use that, you'd probably need to send an amount of rockets that would cripple the economies of all countries in the world. I guess. Even if you'd collect all the waste CO2 in the Earths atmosphere (before it gets exhausted would seem most efficient) that wouldn't be enough because the climate change effect is largely caused by a small difference in consentration. I think. Hope my guessing and thinkng have helped any. DirkvdM 19:34, 24 October 2005 (UTC)[reply]

The chlorofluorcarbon effect on Ozone is still a matter for debate.

What this person wants is a one-way filter to filter out carbon dioxide, something where CO2 will only go through one direction. No such thing exists as far as I know. Simple mechanisms for capturing CO2 already exist one of the simplest is a lime-water solution which will react with CO2 int he air and then drop out of solution as CaCO3. Magnesium will also do this I think. The CO2 can then be released by heating or treating with acid. I presume carbonates exist on Mars, so only the last part of treating with acid would be needed. Ozone is trickier, it is not stable and breaks down into diatomic oxygen in a matter of hours, so your bag from Neptune would no longer be Ozone by the time you go it to Mars. Ozone can be created from Oxygen using an electrical discharge, but since it does not last very long you have to continually do it in large amounts.

Monomolecular blades

In the first book of Star Trek: The Lost Era, a weapon called a "monomolecular blade" is described. It's a knife or sword whose blade is only one molecule thick. It is described as being able to cut through practically anything - cloth, skin, bone, even solid steel - as if it were cutting through hot butter. Would this work in real life, and if so, why? — JIP | Talk 16:22, 24 October 2005 (UTC)[reply]

It's a staple of science fiction that a molecular monofilament (essentially a wire that was one long molecule) would be able to cut through almost anything since its covalent bonds would be much stronger than the typical Van der Waals or ionic bonds that are the inter-molecular bonds in most things. A blade would be similar. However, I don't know how realistic this is in terms of numbers. --Bob Mellish 17:02, 24 October 2005 (UTC)[reply]

We could probably test this, by holding a carbon nanotube. If it falls through the hand, its true. -- Ec5618 19:30, 24 October 2005 (UTC)[reply]

If it is one molecule wide and many thick, you would find that in the diction of cutting it may be stiff, but the lateral stiffness of a sheet one molecule thick may be lacking, IMHO. Carbon nanotubes are not one molecule thick. As I recall, bayonets with serrations were especially deadly, to the point that during WWI if you were captured with one, you usually were going to die of your wounds, past or future. Clean cuts are not always as deadly. Dominick ^(ŤαĿĶ) 20:03, 24 October 2005 (UTC)[reply]

It was always my understanding that the serrations of which you speak weren't on the sharp side of the blade but on the back of the blade. The notches were cut so that they would tear at the organs/muscle/skin on the blade's way out of the wound it has just made. Therefore a surgeon would have a harder time sewing up the wound. That is if the person even made it to a surgeon considering the additional loss of blood caused by such a nasty wound. Dismas|^(talk) 07:47, 25 October 2005 (UTC)[reply]

"Carbon nanotubes are not one molecule thick" I beg to differ. Not only are they one molecule thick, they are one molecule long. Some double walled tubes have been made, which would technically still be a single molecule thick, and long.-- Ec5618 20:26, 24 October 2005 (UTC)[reply]

Ripping sound from an mpeg file

So I have an mpeg file and I want to pull the sound from it. Are there any free (gratis or libre) programs for Windows that can do this? I see some from googling, but none that I had any idea whether they were spyware free, which is important. If it matters what type of mpeg encoding, how do I tell which it is.? Related question, does anyone know similar software to rip the sound directly from a DVD? (short bits to qualify for fair use of course). Thanks - Taxman ^Talk 19:14, 24 October 2005 (UTC)[reply]

MPlayer (http://www.mplayermq.hu/) and VLC (http://videolan.org/vlc/) are two great open-source media players, and I'm pretty sure both of them have options to dump audio or video to another file. For MPlayer, one of the following command lines should extract the audio from just about any file:

mplayer -ao pcm filename
mplayer -dumpaudio filename

The former will decode the audio to a WAV file, while the latter will just demultiplex it from the video without decoding or altering it. For a DVD, I think you can use dvd://1 as the filename, but there might be additional options. VLC would probably be easier to use, as I believe it has a wizard or something for this, but I can't remember off the top of my head how to do it. Also, if you're on Linux, transcode is an option but I've found it to be a little less robust and more complex than the other two I mentioned. --David Wahler (talk) 19:57, 24 October 2005 (UTC)[reply]

Thanks, great tips. I didn't reallize mplayer ran on Windows too, or offered output streams like that. I'll play with those and see what I can get, and report back any problems. Thanks again - Taxman ^Talk 22:05, 24 October 2005 (UTC)[reply]

Light in a box nr 2

After the 'Light in a box' question above, Eye said I Like this kind of question. Think of another. Well, here's one I thought of as a kid when I learned about those one-way mirrors that are used in police interrogation rooms. If you'd make a sphere (stronger than a box) out of such a material light would build up inside until .... DirkvdM 19:40, 24 October 2005 (UTC)[reply]

Actually, such mirrors allow 50% of light to pass through to the other side, whichever side it comes from. So, 50% of incoming light would enter the sphere, 25% would come out the other side, 12,5% would come out the front, after reflecting, 6,25% would go out the back again. Pretty soon, all light would be lost.

Still, the basic premise is the premise behind lasers. A phased wave of light is continually reflected back and forth through a lasing medium. As the photons reflects they persuade energised molecules to transmit a photon, which follows the original photon, and have the same phase and direction. Finally, when enough power will have built up, the energy will be allowed to come out of the lasing medium on either side, creating the beam of light we all know and love. -- Ec5618 20:23, 24 October 2005 (UTC)[reply]

Those are partially transparent mirrors. The secret is that the "invisible" side has a lot less light than the other side, so most of this light is reflected and you can't see it, while plenty of light rays from the bright side pass. Light is partially reflected from both sides. So, I think the situation here wouldn't even be interesting, since all light inside the sphere would just go throught its walls eventually. ☢ Ҡieff⌇↯ 20:16, 24 October 2005 (UTC)[reply]

A light catcher. I like it. I feel a science fiction story comming on...The evil Lord of Darkness has stolen the Light Catcher because he who controls the light controls the universe....Ha! Ha! (evil laugh):-)--Eye 20:24, 24 October 2005 (UTC)[reply]

added after edit conflict:

Nope, sorry. One-way mirrors are actually completely symmetrical; they just appear one-way because the room on one side is much more brightly illuminated than the other. From the brightly lit side, the reflection of the room in the mirror is so much brighter than the light transmitted from the other side that it washes everything out. From the darker side, on the other hand, there's much less reflection and much more transmission. You can test this for yourself; go up to a "mirror" like this and put your eyes up close to it. If you use your hands to block out the ambient light, you'll be able to easily see through the mirror. So in answer to your question: any material that you could use to construct your sphere would let light out just as easily as it would allow it in.

It's actually one of the fundamental theorems of computer graphics that any path will transmit light equally in either direction; I'd give you more information, but I can't for the life of me remember the name of the law. I do remember that there was a relatively recent SIGGRAPH paper demonstrating it in an interesting way—they managed to set up a system where they could use a digital projector as a virtual camera, and vice versa. --David Wahler (talk) 20:24, 24 October 2005 (UTC)[reply]

To clarify, a "one-way" mirror isn't actually "one-way" at all - it must (from thermodynamics arguments) let the same fraction of light go through one way as the other. If you flipped one back-to-front, it would work just the same way. --Bob Mellish 20:25, 24 October 2005 (UTC)[reply]

Hmmm, I could have thought of those things myself. Actually I now remember once seeing that 'coming up to the mirror with hands cupped around the eyes' thing in a film. Ah, well, another childhood fantasy gone to smithereens. Next you'll be telling me Sinterklaas doesn't exist .... DirkvdM 06:32, 25 October 2005 (UTC)[reply]

I think the existance of Sinterklaas has been pretty well established. Ask another .. ? -- Ec5618 06:40, 25 October 2005 (UTC)[reply]

Salt Ice Cream

How does salt lower the temperature of ice in one of those hand cranked ice cream tubs?--Eye 20:04, 24 October 2005 (UTC)[reply]

Does it? There are salts that, when allowed to mix or disolve, will react endothermically, causing the temperature to raise. I've heard of those being used to cool icepacks in medical kits, but never for icecream. I believe Ammonium chloride is an example. -- Ec5618 20:23, 24 October 2005 (UTC)[reply]

It doesn't. Salty water has a lower freezing point, so you can get liquid water below 0° C. Since liquid takes the shape of its container, this very cold, salty water gets in contact with a larger area than a bunch of ice cubes, so it freezes more efficiently. ☢ Ҡieff⌇↯ 20:19, 24 October 2005 (UTC)[reply]

The salt melts the water, since water has a heat of formation, the amount of energy needed to take water from liquid to solid at the same temperature, the energy to do this has to be taken from somewhere, so the temperature of the water lowers.

Spicy Foods

What is the best (fastest) way to get rid of the "hot" feeling in your mouth and/or throat when eating spicy foods such as jalapenos? (Jakz34 21:13, 24 October 2005 (UTC))[reply]

I favor eating absorbtive bread, though I think chemical bases like milk are also supposed to be effective. — Lomn | Talk / RfC 21:42, 24 October 2005 (UTC)[reply]

I believe milk works because the spicy-tasting molecules (capsaicins) are soluble in fat, but not in water (which is why drinking water doesn't seem to quench the fire). Things like yoghurt also work for the same reason. Though serious curry eaters swear by beer, preferably lager, perhaps because of its well-known topical numbing effect. --Bob Mellish 21:56, 24 October 2005 (UTC)[reply]

Yup, our capsaicin article lists those, but also comments they don't necessarily work. (And gives no references or justification either way). Maybe once you're pain sensors are pissed off at you, they don't calm down till some time after the actual irritant, capsaicin, is gone. But don't worry, the endorphin rush should make up for the pain for you. Sucking on ice cubes after eating something like buttered bread seems to help the most to me. The ice doesn't get rid of the pain any faster, but dulls it pretty well for as long as the ice is there and makes it livable until it actually goes away. - Taxman ^Talk 22:05, 24 October 2005 (UTC)[reply]
Chinese food generally comes with krupuk (prawn crackers), does it not? These are included to clear the palette. -- Ec5618 21:58, 24 October 2005 (UTC)[reply]

In my opinion, celery does an excellent job neutralizing spicy foods. I suppose thats why they serve celery with Buffalo wings. - Cobra Ky (talk, contribs) 22:48, 24 October 2005 (UTC)[reply]

If the fat in milk and the cold of ice help, then shouldn't ice cream be a miracle solution? Hmmm, ice cream for desert after a curry? DirkvdM 08:04, 25 October 2005 (UTC)[reply]

Carbohydrates (bread, rice), dairy (milk, yoghurt) or alcohol all work, although individuals may get more milage from one or another. Trollderella 02:43, 27 October 2005 (UTC)[reply]

October 25

Earth

How fast does the earth spin around the sun? Name:Aidan Age:8

Have you seen our article titled year?--inks ^T 00:06, 25 October 2005 (UTC)[reply]

The earth circles the sun once a year, traveling at a velocity of roughly 27 000 000 000 000 000 000 000 miles per year, or about 74 000 000 000 000 000 000 miles a day, or about 3 000 000 000 000 000 000 miles an hour. The earth circles its own axis (spins on its axis) once a day, at an equatorial velocity of roughly 24,000 miles a day, or about 1,000 miles an hour. alteripse 00:10, 25 October 2005 (UTC)[reply]

Mmm, the speed of light is only 670,616,629 miles per hour, and nothing travels faster than this. The Earth article (and this website) say the Earth's speed around the sun is 30 km/s = 18.6 miles/s = 108000 km/h = 66960 miles/h.

OK, probably I shouldnt have done off the top of my head math. I was remembering 24,000 mi circumference, 93 million miles to sun (=radius of orbit), and pi r squared for the diameter of the orbit travelled in a year. Where did I make my mistake? I see, I think I used too many zeroes and squared 93 trillion rather than million, and the diameter is pi x r not pi r squared. That would do it, wouldnt it? 93 million x pi would be 292 million mi for orbital diameter in one year, or 800 000 mi per day, or 33 333 mi per hour. Now I agree within a factor of 2. Where is my mistake? alteripse 00:53, 25 October 2005 (UTC)[reply]

Circumference is 2πr, not πr. --David Wahler (talk) 00:58, 25 October 2005 (UTC)[reply]

Good thing I don't make a living doing this sort of thing. Thanks for cleaning up after me. alteripse 01:01, 25 October 2005 (UTC)[reply]

pi r squared will give you the area encompassed by the orbit of the earth. Since the orbit is not a perfect circle, neither calculation is 100% correct.

This question was asked, and answered, farther up the page. It's question #8. Dismas|^(talk) 07:38, 25 October 2005 (UTC)[reply]

Isn't there a Monty Python song about this? Trollderella 02:47, 27 October 2005 (UTC)[reply]

Dehydrohalogenation

Hello and thank you,sir,for answering my previous question.I now want to know about dehydrohalogenation.I read about this in an article about Pharmaceuticals. Please tell me what does it mean. Thank you.

Please search first. See Hydrohalogenation. The prefix de- suggests the reaction is reversed.

CH₃-CHBr-CH₃→CH₃-CH=CH₂ + HBr

Any other halogen could be used instead of the Br. -- Ec5618 06:48, 25 October 2005 (UTC)[reply]

Photograph Enhancements

Are those photograph enhancements (like finding out a cars number plate from a blurred picture) that they show in the TV shows and movies really possible, and if so, how do they work? --AMorris (talk)●(contribs) 08:55, 25 October 2005 (UTC)[reply]

Short answer: no. Longer answer: There are methods to make certain details clearer, by sharping and changing contrast, analyzing different color channels and manipulating them individually, etc etc. These are possible, but they're not miraculous. But, when you see on the movie someone zooming on a video, and a magic line crosses the screen revealing extra detail out of big pixels, well, no, that's just (mathematically) impossible. If the detail was not there, stored in the first place, you can't retrieve it out of nowhere. ☢ Ҡieff⌇↯ 09:47, 25 October 2005 (UTC)[reply]

No. Enhancement is basically filtering. Filtering allows us to increase contrast, for example, or to remove certain types of noise, which might make details that were previously impossible to see with the naked eye, visible. Filtering always means some data is lost, however.

Enhancent is also a very subjective concept, which means there could never be such a thing as an 'enhance image' option on your computer. -- Ec5618 09:07, 25 October 2005 (UTC)[reply]

In general, the incredible 'enhancement' you see on television and in movies is complete nonsense; it's a crutch for incompetent scriptwriters. It's worth noting that if you have access to more information than one image, it's sometimes possible to pull a bit more detail out of a frame. For instance, if you have a series of video frames of an object generated under specific conditions, it is sometimes possible to generate a combined image with more detail than any single still frame from the series. TenOfAllTrades(talk) 12:52, 25 October 2005 (UTC)[reply]

Further to this, there are some tricks that allow multiple images from different positions to be used to get an image that has far more detail than any of the single images. There was some discussion of this on the reference desk earlier. Nifty, but still not the magic enhancement button you're asking for...--Robert Merkel 14:21, 25 October 2005 (UTC)[reply]

Lots of tricks are possible if you HAVE ADDITIONAL INFORMATION. For example if you know a fuzzy image has to be 0-9,A-Z in a specific font (example: a Florida license plate) a computer can often resolve an otherwise unresolveable fuzzy image. WAS 4.250 02:20, 26 October 2005 (UTC)[reply]

You can often solve these problems the analog way. You can manufacture license plates of various numbers and alphabets such as A55ÕRGY and take pictures under recreated lighting condition. -- Toytoy 04:50, 26 October 2005 (UTC)[reply]

media

Do the media act as agents that reproduce social inequalities or are they the "glue" that binds society togather?

Be specific - explain your question in detail if necessary, addressing exactly what you'd like answered. For information that changes from country to country (or from state to state), such as legal, fiscal or institutional matters, please specify the jurisdiction you're interested in.
Do your own homework - if you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers.
Sign your question - type --~~~~ at its end. -- Ec5618 10:29, 25 October 2005 (UTC)[reply]

The answer to your question is 'yes'. Or, possibly, 'no'. It's almost certainly one of those, however. TenOfAllTrades(talk) 12:39, 25 October 2005 (UTC)[reply]

Hurricane Wilma

Why did hurricane Wilma move so slowly in the Gulf of Mexico, and then suddenly move quickly after it hit Florida? Is it because the water along the East Coast moves quicker? Or because of the jet stream? --216.191.200.1 12:56, 25 October 2005 (UTC)[reply]

While I'm not sure, you might like to read Tropical cyclone#Movement and track, which discusses cyclone movement. It states:

"Although tropical cyclones are large systems generating enormous energy, their movements over the earth's surface are often compared to that of leaves carried along by a stream. That is, large-scale winds—the streams in the earth's atmosphere—are responsible for moving and steering tropical cyclones." -- Ec5618 13:59, 25 October 2005 (UTC)[reply]

You may want to specifically ask User:E. Brown. He seems to like hurricanes. --Lord Vold e mort ^{(Dark Mark)} 19:30, 25 October 2005 (UTC)[reply]

Finding positions of desktop icons under windows

Does anyone know where on windows the desktop icons positions are stored? I've been searching the registry without luck and I'd appreciate some help. --Andy

Suggestion: get Regmon and/or Filemon, run them, and try moving the icons around. These program monitor any registry / file changes on a system, and are very useful. --Bob Mellish 16:13, 25 October 2005 (UTC)[reply]

Well, i tried the programs but they're hardly useful since there's too much stuff going on...--Andy

HKEY_CURRENT_USER\Software\Microsoft\Windows\Shell\Bags\1\Desktop [21] --Majts 21:20, 25 October 2005 (UTC)[reply]

Also this thread is interesting as it shows which key settings in that hive control things like auto arrange --Majts 21:34, 25 October 2005 (UTC)[reply]

Open source licenses

I have just developed a program that I want to release as open source with the source code.

I want to retain all copyrights to the work.
I want to let people modify/improve the code and release their improvements, but they cannot claim they wrote the original work or claim they own the copyright to it.
Any messages/text that show me as the author and copyright holder must remain intact, and any modified versions not by me must be clearly marked as such.

I'm new to all this, so what would the best license be to use? --82.18.254.3 18:02, 25 October 2005 (UTC)[reply]

I would recommend you check out Creative Commons, as they work to help people identify specific licenses for their needs by asking the user for criteria such as yours. I recommend you check this, rather than giving a specific license, as the process may uncover additional criteria you've not yet considered. — Lomn | Talk / RfC 18:13, 25 October 2005 (UTC)[reply]

To clarify one of the subtler points you may not have thought of: Suppose somebody takes your code, makes some modifications to it and starts distributing it. Do you want to force them to distribute it under the same free license as well, or should they be able to set their own terms? This seems to be one of the most controversial aspects of different open source licenses these days.

The GPL takes the position that if the code is free, all the derivatives must be free and licensed under the same terms. The BSD license, on the other hand, lets others take the code and do whatever they like with it; this seems pretty close to what you're suggesting. I personally lean towards the BSD camp, since nothing anybody else does will affect my code one way or the other. However, it's a personal choice, and I can easily imagine why someone else might feel differently. Incidentally, Creative Commons licenses allow you to choose between these alternatives—you can optionally include what they call a "share alike" clause. --David Wahler (talk) 19:47, 25 October 2005 (UTC)[reply]

The major open source licenses are the BSD license, the GPL and the Mozilla Public License. Putting your code under BSD is almost like realeasing it into public domain except that you retain your copyright and modified code must display this copyright message. The GPL makes your requirements much more explicit (the license text is more that ten times as long), but also requires that any modfied version is licensed under the GPL. Depending on who you ask this will increase or decrease the freedom of your code. (Software that is licensed under the BSD license can be 'upgraded' to GPL, but GPL software cannot be 'downgraded' to BSD). The MPL adds some extra legal protections that are useful if you want to distribute a commercial version aside from an open source version. Personally, I license my code under the GPL. --R.Koot 21:57, 25 October 2005 (UTC)[reply]

Looking at your requirements, you retain the copyright to any code you write, regardless of the licence. Therefore, you can do anything you want with it, including reusing it as part of a proprietary product. So that part is irrelevant to your choice of licenses.

All of the major open source licenses (the GPL, BSD-style, and MPL as described by R. Koot) note that you retain your copyright to your original work, and require that anybody redistributing your work, or a modified version thereof, must retain your original copyright notice.

The GPL specifically requires that any modified version carry prominent notice of the modification (see section 2 of the license text). Most of the BSD-derived licenses do not have such a requirement explicitly. Instead, they have a requirement that the names of the authors not be used to promote the software unless further written permission is given. For instance, the XFree86 Project's license states the following:

Except as contained in this notice, the name of the XFree86 Project shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from the XFree86 Project.

If you wish, though, there's nothing stopping you from adding a specific clause to a BSD-style license that says any modified version must be marked as such. Such a license would still be an open source license.

Note that the GPL requires a number of other things of people who redistribute or modify your software beyond your requirements. It is up to you to decide whether you think these requirements are a good or a bad idea.

Hope this helps. --Robert Merkel 04:37, 26 October 2005 (UTC)[reply]

When I release things with a license, I like to use the Artistic License. It has a clause that states that other people can't sell your project for a profit, which was important to me -- in the off chance that someone is going to profit from my hacks, I want it to be me. Otherwise, it's a pretty short and loose license. With respect to Creative Commons, I think columnist John C Dvorak is a bit of a tool, but he makes some good points in this criticism of the system. Garrett Albright 14:46, 26 October 2005 (UTC)[reply]

If I may ask, what good points? The arguments Dvorak makes seem to apply to all free/open licenses, not just Creative Commons. In fact, his main problem with CC appears to be that "it seems to actually weaken the copyrights you have coming to you without Creative Commons. Oh, brother!" Ilmari Karonen 20:37, 26 October 2005 (UTC)[reply]

No joke. The guy's an idiot, at least on that article. He doesn't seem to have bothered to actually have read anything by Lessig (or any of ther other Free Software folks) and as such is completely clueless about the structure of the licenses, which are really not that complicated. "Why would anybody even want this? I'm totally confused! Professor Lessig must be a friggin' idiot!". Uh, right. --Fastfission 02:12, 27 October 2005 (UTC)[reply]

The fact that a license can stand on its own without the backing of a wealthy organization and a cutesy trendy logo, for one. Also, while Dvorak doesn't mention it, the fact that a CC license can vary from fairly restrictive to full-on public domain can be confusing. Garrett Albright 14:31, 27 October 2005 (UTC)[reply]

I don't know about you, but if I'm going to release my work under anything more restrictive than the BSD license, I'd rather like to have "the backing of a wealthy organization" behind it, whether that organization is CC or the FSF. After all, I hardly have the means to sue some big corporation if they violate the terms of my license. I don't know about CC, but the FSF at least seem to be more than happy to help. Cutesy trendy logos are completely optional, but nice enough. (As for the potentially confusing variety of CC licenses, I grant you that point. Not that Dvorak seems to get it, since he shows no indication in that article of being aware that there is more than one CC license.) Ilmari Karonen 17:31, 27 October 2005 (UTC)[reply]

seedless fruits

Where do the seeds go in seedless fruits, or, how do these fruits become seedless?(some grapes, watermelons,oranges etc.) Are there different methods or reasons for this? If so, what are they? Thanks! Hattie

There's a small amount of information in our article on fruit, but not much. Basically, seedlessness (also known as parthenocarpy is a natural mutation that occasionally occurs in the wild. Normally, plants without seeds would die without being able to reproduce; however, humans can and do selectively cultivate seedless plants by various techniques related to cloning.

As far as I know, there are two main reasons for preferring seedless plants:

In fruits that are consumed by humans, seedlessness is aesthetically preferred.
Because the plant is forced to reproduce asexually, the amount of variation in its descendants can be very tightly limited.

Hope this helps. --David Wahler (talk) 21:37, 25 October 2005 (UTC)[reply]

While the original bananas contained rather large seeds, seedless and triploid varieties have been selected for human consumption. These are propagated asexually from offshoots of the plant. The plant is allowed to produce 2 shoots at a time - a larger one for fruiting immeditely and a smaller 'sucker' or 'follower' that will produce fruit in 6 - 8 months time. The life of a banana plantation is 25 years or longer, during which time the individual stools or planting sites may move slightly from their original positions as lateral rhizome formation dictates. Latin Americans sometimes comment that the plants are "walking" over time. from Banana WAS 4.250 02:28, 26 October 2005 (UTC)[reply]

I found this quote: The seeds for growing [seedless watermelons] are produced by crossing a normal diploid watermelon with one that has been changed genetically into the tetraploid state. The seeds from this cross produce plants that, when pollinated by normal plants, produce seedless melons. [22] There is more about advantages (including sweeter flesh and more vigorous growth), techniques, etc. Notinasnaid 08:56, 26 October 2005 (UTC)[reply]

Cavities are bad

Which is worse for your teeth: Coffee or Soda? --Lord Vold e mort ^{(Dark Mark)} 19:33, 25 October 2005 (UTC)[reply]

This probably depends mainly on whether one takes sugar in their coffee. Without sugar it shouldn't lead to cavities, but it will stain teeth. In fact, coffee has been found to prevent some microorganisms, such as Streptococcus mutans, from adhering to teeth, which would help to prevent cavities. The chemical responsible appears to be trigonelline. [23]

Besides the sugar, sodas contain carbonic acid and often phosphoric acid, which may have an additional (small) effect on tooth enamel. ‣ᓛᖁ♀ᑐ 20:17, 25 October 2005 (UTC)[reply]

Except isn't coffee very acidic? It doesn't eat through enamel? I haven't done any pH tests in a long time, so I don't really remember. Thanks anyway, Eequor. --Lord Vold e mort ^{(Dark Mark)} 21:01, 25 October 2005 (UTC)[reply]

This site suggests that the pH of a good cup of coffee should be approximately in the range of 4.9 to 5.2. This site indicates that the pH of carbonated cola beverages is around 2.5; cola is much nastier stuff. TenOfAllTrades(talk) 21:09, 25 October 2005 (UTC)[reply]

Soft drinks containing relatively high quantities of phosphoric acid (this includes most proprietary colas) are capable of dissolving the mineralisation of teeth. If you have (are) a pre-adolescent child with newly fallen deciduous teeth to spare, you can prove this by leaving one in a glass of cola. BEWARE: after a week or so, there will be nothing left for the tooth fairy to find. Physchim62 21:43, 25 October 2005 (UTC)[reply]

I suppose you mean soda pop, not sodium (aka soda). In Dutch 'soda' means the latter. I now wonder if that is also the original meaning in English and, if so, why the drink was named after it (or was it?). DirkvdM 09:05, 26 October 2005 (UTC)[reply]

Isn't the reference desk wonderful? I ask a question and within a short period of time I get all kinds of response. I guess it seems soda (a.k.a. soda pop) is worse. Now I just need to find some kid's teeth to knock out and try Physchim62's experiment. See ya everybody. --Lord Vold e mort ^{(Dark Mark)} 13:43, 26 October 2005 (UTC)[reply]

What did cellophane replace?

Just curious, I haven't seen this on the article... --65.117.156.222 19:34, 25 October 2005 (UTC)[reply]

Greaseproof paper and tin foil. Still used, but for different purposes now. smurrayinchester^{(User), (Talk)} 19:59, 25 October 2005 (UTC)[reply]

Skeletal, smooth, and cardiac muscle evolution

Does anyone have any information on the evolutionary pathway of muscles? I was wondering also if this info can be applied to a possible muscle evolution article on wikipedia. 64.12.117.12 21:56, 25 October 2005 (UTC)[reply]

Sounds like it should be covered in an article with a broader scope. It's not though. -- Ec5618 23:04, 25 October 2005 (UTC)[reply]

Ok, but I still want to know the evolutionary pathway of muscles. Can anybody suggest any good links and or references? We can also integrate this information into the muscle page if the topic isn't broad enough to merit its own article. 64.12.117.12 00:13, 26 October 2005 (UTC)[reply]

"Phylogenetic Relationship of Muscle Tissues Deduced from Superimposition of Gene Trees", Satoshi OOta and Naruya Saitou, Mol. Biol. Evol. 16(6) 856-7, 1999 pdf or html: abstract: "Muscle tissues can be divided into six classes; smooth, fast skeletal, slow skeletal and cardiac muscle tissues for vertebrates, and striated and smooth muscle tissues for invertebrates. We reconstructed phylogenetic trees of six protein genes that are expressed in muscle tissues and, using a newly developed program, inferred the phylogeny of muscle tissues by superimposition of five of those gene trees. The proteins used are troponin C, myosin essential light chain, myosin regulatory light chain, myosin heavy chain, actin, and muscle regulatory factor (MRF) families. Our results suggest that the emergence of skeletal-cardiac muscle type tissues preceded the vertebrate/arthropod divergence (ca. 700 MYA), while vertebrate smooth muscle seemed to evolve independent of other muscles. In addition, skeletal muscle is not monophyletic, but cardiac and slow skeletal muscles make a cluster. Furthermore, arthropod striated muscle, urochordate smooth muscle, and vertebrate muscles except for smooth muscle share a common ancestor. On the other hand, arthropod nonmuscle and vertebrate smooth muscle and nonmuscle share a common ancestor"

I need 15 math facts for the number 95.

Be specific - explain your question in detail if necessary, addressing exactly what you'd like answered. For information that changes from country to country (or from state to state), such as legal, fiscal or institutional matters, please specify the jurisdiction you're interested in.
Include both a title and a question - the title (top box) should specify the topic of your question. The complete details should be in the bottom box. Questions not following this format may be deleted.
Be courteous - questions are answered by humans, not computers. This is not a search engine. Don't write in ALL CAPITAL LETTERS.
Do your own homework - if you need help with a specific part or concept of your homework, feel free to ask, but please do not post entire homework questions and expect us to give you the answers. -- Ec5618 23:34, 25 October 2005 (UTC)[reply]

Is that homework? -- SCZenz 22:47, 25 October 2005 (UTC)[reply]

95 is a semiprime, being the product of two prime numbers, 5 and 19.
Its proper divisors add to 25; it is a deficient number.
It is the number of planar partitions of 10. [24]
It is the fifth hendecagonal number.
It is 1 less than 96
It is 2 less than 97, etc AllanHainey 11:24, 26 October 2005 (UTC)[reply]
Its 1011111 in binary ..
10112 base 3
1133 base 4
340 base 5
235 base 6
164 base 7
137 base 8
115 base 9
And of course 5F in base 16 (hexadecimal) --Majts 18:53, 26 October 2005 (UTC)[reply]

Reverse Stockholm Syndrome

Posting here because this got no response in 'humanities' -

Is there a term for Stockholm Syndrome in reverse - ie, the captor developing a love for his victim ? Tintin 23:08, 25 October 2005 (UTC)[reply]

No --Majts 18:55, 26 October 2005 (UTC)[reply]

Thanks Tintin 23:01, 26 October 2005 (UTC)[reply]

- Somones been watching Waking the Dead ;) -Rob

The reason is that it is a normal thing for a person to begin to sympathize with those around them. The Stockholm Syndrome is only worth noting in that it seems quite bizzarre that a person who is kidnapped and threatened with death would sympathize with their kidnappers to such an extent that they will then kidnap and kill others to further their cause. StuRat 16:13, 29 October 2005 (UTC)[reply]

October 26

What are the airplane window manufacturers?

Who manufactures passengers' small windows for Boeing and Airbus? Are these windows interchangeable between different airplane models (other than advanced Boeing 787 windows)? -- Toytoy 00:45, 26 October 2005 (UTC)[reply]

I'd tell you, but then I'd have to kill you :) They are made by subcontractors to Boeing and Airbus, unfortunately, I don't know which ones. And while they look similar, no, they're not interchangeable (except between very closely related aircraft, like the Airbus A318/319/320/321 family, which are just different-length versions of the same plane). QuantumEleven | (talk)

How to breakup stamps for the maximum profit?

This hot babe may worth $577,500! You can use the money to buy a real airplane!

From Inverted Jenny:

"The inverted Jenny (or Jenny Invert) is a United States postage stamp of 1918 in which the airplane in the center of the design was accidentally printed upside-down. Only 100 of the inverts were ever found, making this error one of the most prized in all philately ..."

A block of four was auctioned May 19 in New York for $2,970,000 and set a world record.

The 100 inverts were from a sheet accidentally purchased by collector W. T. Robey. The collector "quickly resold the entire sheet to a dealer for $15,000. Within a few weeks, the stamps were separated, with most sold off individually for a few hundred dollars each. A few blocks of four were preserved." [25]

If you were the dealer, what would you do? What is your strategy to separate the stamps? A complete sheet is beautiful but how do you sell it? How much can you ask for it? With only one buyer, you can only milk him/her so much. What is the plan or strategy of separation? ... -- Toytoy 01:32, 26 October 2005 (UTC)[reply]

If I were the dealer, I'll do a quick survey of possible buyers, how many of them, how much would they pay, before I separate the stamps.

The buyers would also want to know how many stamps the dealer plans to keep. The last thing you want is to pay 10,000 dollars for one piece of stamp and find out the dealer still has 99 stamps somewhere in a safe. You can never resell your stamp for a reasonable profit because if you want to sell your stamp for $500, I can always separate another stamp and sell it at $450. Probably I cannot keep too many stamps. People know there must be at least 100 of them.

Maybe I can mail one stamp and use the cancelled stamp to create a false sense of rarity. "See, the first owner was too dumb to waste 95 stamps to send mail order catalogs. Many used stamps are now simply gone. I managed to buy his 5 remaining stamps."

Maybe I'll keep lots of stamps and sell my first batch to some fat and foolish buyers. ;) -- Toytoy 01:51, 26 October 2005 (UTC)[reply]

Any decent collector would be able to tell the difference between a modern cancellation and one from circa 1918. There's also a good chance it would get stolen if you tried to mail it. -Drdisque 01:58, 26 October 2005 (UTC)[reply]

I mean if I were the dealer of 1918. -- Toytoy 02:21, 26 October 2005 (UTC)[reply]

I seem to remember a short story where a dealer bought the only 4 remaining stamps in the whole world of an extremely rare set, and promptly burned 3 of them to massively increase the value of the final one. Can't remember the author, though. Proto t c 12:01, 26 October 2005 (UTC)[reply]

Personally, I don't think burning three stamps makes sense. The remaining stamp may gain some value, but very likely not that much. If these stamps belong to the "2nd tier", maybe increased rarity can boost its value. A stamp used to worth $10,000 may become $50,000 if you burn the three of them. Maybe not.

If these stamps are first class ones, you may lose a lot by burning three of them. You may find many collectors willing to pay $1,000,000 for your stamp, but none of them can afford to pay $5,000,000. So you sell the remaining stamp to someone at $1,200,000. There are too many rare stamps. People can always chase after other ones.

The moral of the story: Find a cash cow before you reach the lighter. If your cash cow is fat and dumb enough, burn the three stamps. Otherwise, let other collectors own them. -- Toytoy 14:51, 26 October 2005 (UTC)[reply]

heterolithic vs monolithic breccia

What is the difference between heterolithic breccia and monolithic breccia?

It depends on the mechanical processes which have broken up the original rocks. If the original rocks were clumped together by a landslide, say, then they may well have come from the same type of stone, such as limestone. Hence monolithic. But those rocks are then conjoined by a chemical process again, then they can form breccia. Same answer for heterolithic, except that the original rocks are of different types of stone. Ancheta Wis 09:20, 26 October 2005 (UTC)[reply]

The Mickey Mouse strategy

Copyrights last forever because when your Rotten Rodent copyrights are about to expire, you hire some crooked politians to extend these rights.

Now, imagine you're a fat rat farm owner who wants to buy some years from the Banana Congress. What would you ask for?

If you ask for a 100 zillion year extension, it will take lots money to buy every naysayer. Even if you do it, you can only enjoy a few year's benefits. After that you retire and die. You don't want to give free meals to your heirs from your pockets.
If you only ask for a miseralbe 3-week-cheap extension it will not be worthy of anyone's trouble.

What would you do? -- Toytoy 04:39, 26 October 2005 (UTC)[reply]

See rhetorical question. Notinasnaid 08:35, 26 October 2005 (UTC)[reply]

Since you're interested in rodents, perhaps you might want to read our Rat choice article or this Krugman column on Rat Democracy. David 08:59, 26 October 2005 (UTC)[reply]

Practically, you ask for 20 years' extension to existing copyrights, and do so every 10-20 years. See Sonny_Bono_Copyright_Term_Extension_Act and THE MOUSE THAT ATE THE PUBLIC DOMAIN for examples where this has already happened. (I happen to think you're correct about congress being purchased, b.t.w.) Ojw 21:48, 28 October 2005 (UTC)[reply]

Can big cats purr?

I'll assume you mean can for the first word. Anyway, the answer appears to be some. See our article on purring and the discussion at lion. — Lomn | Talk / RfC 16:05, 26 October 2005 (UTC)[reply]

Yet another light-in-a-box question

Reading the past couple of questions about this lead me wonder: If light can be reflected by the inside of a prism (total internal reflection), would it be possible to send light into a prism so that it could not escape. If so, what would happen as you kept sending light into it? smurrayinaHauntedHouse...Boo!^{(User), (Talk)} 17:33, 26 October 2005 (UTC) [reply]

Internal to the prism there is loss, and due to that loss, the light will eventually decay. If you put enough light in, I suppose the loss in the prism would eventually add, until the prism melts from the heat that is created from the lost light. There is no light explosion. A laser is effectivly a light box, light traveling along the medium in the middle is amplified by stimulated emission, and eventually the light escapes from one end. You will find that lasers have to be cooled, due to losses in exciting the medium that supports the stimulated emission, as well as transport losses. Dominick ^(ŤαĿĶ) 18:06, 26 October 2005 (UTC)[reply]

Your invention looks exactly like a multi-mode, step-index optical fiber to me. You need perfect total internal reflection and your material must absorb no light to "work". Scattering resulted from multiple sources, including impurities (e.g. water) and slightly imperfect geometry, can easily ruin your try. If you pump too much light into your prism, you end up having some sort of unexpected nonlinear optical reactions. -- Toytoy 01:28, 27 October 2005 (UTC)[reply]

Ha! If you know this, then how is it unexpected? DirkvdM 08:58, 27 October 2005 (UTC)[reply]

Oops! If a lightening hits me. I know I shall become a superhero. I just don't know what kind of superhero I'll become. -- Toytoy 11:36, 27 October 2005 (UTC)[reply]

Calibration of Diesel Engine / Powertrains

Hi Friends! I am in a situation where I need to know something on how the diesel engine is calibrated. Basically, I am awaiting an interview call and the company is expecting me to have atleast some knowledge on the calibration. I tried to look for it on the search engines but could not find any information. I need to know, what is involved in the calibration of the diesel engine and how is it done? What are the things usually involved in the calibration process? I would appreciate any kind of positive response.

Thanks, Sush.

You probably need a technical manual of some kind. It will likely depend on exactly what kind on engine. A shop manual for the kind of thing you are expecting to work on would likely help. Trollderella 03:31, 27 October 2005 (UTC)[reply]

This would be through adjusting the governor or the injector pump. With a modern engine, much of this would be done through a computer. read more how diesels work at Diesel engine. -Drdisque 05:13, 27 October 2005 (UTC)[reply]

antacids

when I put a MOM tablet(milk of magnesia) into a beaker of hydrochloric acid, it changes color. I don't understand why.

how would the tablet(MOM) respond to the actual stomach when the stomach continues to secrete acid?If you could please reply.. thanks.

Not knowing the chemical makeup of MOM offhand, I can't be specific, but the former is the result of a chemical reaction. The color likely corresponds to a salt formed by the reaction of an acid and a base. For the latter, stomach acid is neutralized (along with the MOM) until the lesser of the two reagents is exhausted. Since the stomach will produce acid long after the tablet will release MOM, the stomach will remain acidic, the stomach will remain acidic (though less so than prior to the tablet). — Lomn | Talk / RfC 21:02, 26 October 2005 (UTC)[reply]

The active ingredient of MOM is magnesium hydroxide. It reacts with hydrochloric acid to produce MgCl2 which is colorless. If you see a color change it might indicate that your brand of MOM tablet has a stabilizer or sweetener or additional ingredient in the tablet that is reacting with the HCl. Read the fine print on the package of tablets, or try a different brand of MOM. I am assuming you are not doing this with a universal indicator which is designed to change colors as the reaction occurs?alteripse 00:46, 27 October 2005 (UTC)[reply]

October 27

African Hedgehog quills

I have a project in which my topic is "How bacteria helps animals survive" im stuck on the hedgehog. I know they have bacteria in their quills but i was looking into more detail. What bacteria is it, and what infections does it cause, and well i needed a source too. I was hoping someone here could help me. thanks, S.M.

From hedgehog: "Hedgehogs are easily distinguished by their spines, which are hollow hairs made stiff with keratin. Their spines are not poisonous or barbed".

Perhaps you could use the Komodo dragon, which is thought by many people to be a poisonous or venomous reptile. The Komodo dragon does not produce any poisonous or venomous substance, though it has a large population of deadly bacteria living in his mouth.

Some types of snake are also known to have a poisonous bite, thanks to bacteria in the mouth. -- Ec5618 23:45, 26 October 2005 (UTC)[reply]

I don't know about hedgehogs, but another example might be the bioluminescence that some deep sea fish use. I'm just not sure if it's bacteria in this case. And a favourite of mine are the mitochondria, which must be one of the oldest forms of symbiosis. DirkvdM 09:20, 27 October 2005 (UTC)[reply]

Also some spiders have bacteria on their fangs... Alphax ^τεχ 11:39, 28 October 2005 (UTC)[reply]

If your stuck on Hedgehogs, and dont want to switch to Wildebeasts, then you might look at either their eyes, or their digestive tracts. What do they eat, how do they digest, and how is their eyes moisturized? Just remember you have 3 to 4 pounds of flora in your gut, that you almost cannot live without, and your eyes, have many many types of bacteria in them. Artoftransformation 03:30, 27 October 2005, (PST)

Thanks for the response, and well, i am using the komodo dragon, which have 15-50 different types of bacteria, and bioluminescence is bacteria, some. i looked into it myself. Thanks for the tips :D

Life expectancy of triathletes

Was there any study done to find the average life expectancy of triathletes? I know that average life expectancy is somewhere around 77 and 79 years. I have heard many stories of older triathletes being in better physical shape (in terms of endurance and cardiovascular health) than average 20 year olds.

I don't know, but I am 30, and got my ass kicked running with a 70 year old triathlete. I'm not in terrible shape. Trollderella 02:49, 27 October 2005 (UTC)[reply]

Being in a better shape doesn't mean one lives longer. I believe increased metabolism might even reduce ones life expectancy and that especially the increased activity of the heart causes more wear and tear, also reducing the life expectancy. And I once heard that the bigger heart of athletes isn't quite healthy either. A variation on 'live fast, die young', I suppose. DirkvdM 09:36, 27 October 2005 (UTC)[reply]

I think there are too many variables and it hasn't been studied carefully. But to answer your point about wear and tear on the heart from exercise, that is not correct. A person in better shape will have a lower resting heart rate (RHR) than they would have when they are out of shape, because exercise increases the ability of the heart to pump blood. Thus even adding in the extra heart beats during exercise, their heart will beat less over a week or month say. Now the increased metabolism could be right and reduce lifespan, but having a healthier heart may or may not offset that. - Taxman ^Talk 12:38, 27 October 2005 (UTC)[reply]

Assuming the amount of heartbeats per life is given and that during exercise one's heart beats twice as fast and the increased size of the heart would account for a reduced rate of 10% during rest (say 72 in stead of 80 bpm), then the break-even point would be at 10% of one's time spent exercising. With 1/3 of the time spent sleeping only (semi)professional would exceed that. The 10% is just a wild guess, though, and of course will also depend on how much time one spends exercising, so it's a bit interdependent. DirkvdM 15:37, 27 October 2005 (UTC)[reply]

I don't think it's true that in humans the number of heartbeats per life is fixed. In some animals it more or less is, but not in people. Trollderella 17:07, 27 October 2005 (UTC)[reply]

Specific heat capacity of styrofoam cups

OK just a quick question that someone might be able to answer... what is the specific heat capacity of your average styrofoam cup?
-- Миборовский ^U|T|C|E 00:14, 27 October 2005 (UTC)[reply]

I don't know about cups in particular, but my databook gives a value of 1.3 J g^-1 K^-1 for the specific heat capacity of polystyrene. Of course, it depends on the density, but according to the book, practically all plastics are in the range 1.2-2.1 --Bob Mellish 00:36, 27 October 2005 (UTC)[reply]

- And remember that specific heat is an intensive property; the numbers above are the heat capacity per gram, so you will also need to know the mass of the cup. ike9898 00:56, 27 October 2005 (UTC)[reply]

Since styrofoam is expanded polystyrene, will the air trapped inside significantly increase or decrease the specific heat capacity of styrofoam? Or can it be safely assumed to be approximately 1.3 J/gK?
-- Миборовский ^U|T|C|E 01:50, 27 October 2005 (UTC)[reply]

Hmmm. My databook doesn't say if that's for expanded polystrene or bulk. The only reference I can find online is for the structural kind of styrofoam, and gives a value of 0.27 in the wonderful units of Btu/(lb °F). If I've got the conversion right, that's 1.12 J/(g K). So a bit less. --Bob Mellish 02:11, 27 October 2005 (UTC)[reply]

1.12J/gK sounds really low... compared to water. If it's so low how is it such a good insulator?
-- Миборовский ^U|T|C|E 05:49, 27 October 2005 (UTC)[reply]

Isn't that actually the reason for it? If it absorbs no (or little) heat it won't conduct heat either, right? DirkvdM 09:43, 27 October 2005 (UTC)[reply]

Try using the SHC of air, and assume that the amount of polysyrene involved is minimal. Ojw 21:42, 28 October 2005 (UTC)[reply]

Buy a real calorimeter next time--152.163.101.12 21:50, 28 October 2005 (UTC)[reply]

Of course, that's it. The air is really the insulator. The polystyrene is just there to keep it from moving and dissipating heat through convection. DirkvdM 10:21, 29 October 2005 (UTC)[reply]

POLYMERASE CAIN REACTION

FOR WHAT SPECIFIC PURPOSE IS PCR USED?

NAME THE MIXTURES PLACED IN A PCR VIAL AT THE BEGINNING OF THE PCR PROCEDURE?

WHAT IS THE OPTIMUM TEMPERATURE FOR THE ENZYME DNA POLYMERASE USED IN THE PCR PROCESS?

Optimum Temperature? no problem, 40................... now figure out what temperature scale I'm using (-; --152.163.101.12 21:55, 28 October 2005 (UTC)[reply]

We have an article on the polymerase chain reaction which answers these questions. Chuck 00:24, 27 October 2005 (UTC)[reply]

And please turn off your caps lock. DirkvdM 09:44, 27 October 2005 (UTC)[reply]

This looks like a great exam question, or homework. Why would you come here when even a small amount of research on the web would answer these questions? David D. (Talk) 22:05, 28 October 2005 (UTC)[reply]

Resizing windows (microsoft windows, that is)

Sometimes something will happen so that every time I launch Internet Explorer, the window will be some odd size. I want to know 1) what causes this to happen, and 2) how to change it, so that it will open maximized. ike9898 01:06, 27 October 2005 (UTC)[reply]

That seems to be a common problem. Workarounds can be found via Google, similar to this:

Open a single Internet Explorer window to the smaller size.
Drag the corners of the window until it completely fills the screen. Do not use the maximize button to enlarge the window.
Hold down the Ctrl key, keep it depressed, and using the mouse click File and then Exit on the menu bar. Do not use the "X" in the upper right corner to close the window.
Internet Explorer should now open in a full window.
If it still opens to a smaller size repeat the above instructions, substituting the "Shift" key for the "Ctrl" key.

See if it works for you?--inks ^T 01:54, 27 October 2005 (UTC)[reply]

Also, try clearing out your cache as well. For some reason I remember this being related to this, though intuitively I don't know why that would be. --Fastfission 02:41, 27 October 2005 (UTC)[reply]

A method I used (which didn't always work) was to resize the explorer window (IE is just an instance of that), right-click one of the directories to open it in a new window (possibly repeat until it opens in the right size) and then close the last window last. After that they should open in that size and position. A more definite solution involved messing about in the registry (with regedit I believe). But I forgot how (I now use Linux). Be sure to make a backup of the installation, though, because working in the registry is dangerous. DirkvdM 09:52, 27 October 2005 (UTC)[reply]

Thanks! These tricks worked for me. Any idea what causes it to happen in the first place? ike9898 13:57, 27 October 2005 (UTC)[reply]

msWindows sucks? Probably not the answer you were waiting for, but you're unlikely to get an answer to that unless someone at microsoft would bother to help out here (and you can forget about that), because the workings of msWindows are quite obscure. And for a good reason - they don't want people to know, which is the opposite of Linux, which depnds on people (especially programmers) being able to understand the inner workings. And those people will be more likely to help out here because it's a hobby for them. DirkvdM 15:43, 27 October 2005 (UTC)[reply]

Windows

Sometimes when I start my computer, windows boots... No, actually, what I want to know is, is there an open source windows program to take ripped dvds (VIDEO_TS) etc, and turn them into something smaller? Thanks! Trollderella 02:46, 27 October 2005 (UTC)[reply]

There's a version of VirtualDub around that parses mpeg2, so it should be able to handle this. See here. I haven't tried using it with direct dvd rips, though. —Cryptic (talk) 03:45, 27 October 2005 (UTC)[reply]

Thank you! This will take individual files, and turn them into other things, but that will give me a bunch of other files, since my ripper has split the DVD into 2gb files. That's ok, since DVD players just string them all together, but what I want is a program that will take the whole DVD structure, and remaster it as a single, compressed, and playable file... Am I dreaming? Trollderella 03:50, 27 October 2005 (UTC)[reply]

There are various websites that list such programs and often provide tutorials for using them. You might want to check out doom9.org or afterdawn.com, for example. (Note: The legality of ripping DVDs varies between jurisdictions. Before downloading DVD ripping tools, please make sure local law allows their possession and use. Or, failing that, try not to get caught. ;-)) Ilmari Karonen 17:14, 27 October 2005 (UTC)[reply]

Thanks - I'm not distributing them, just trying to make my backup archive smaller. Trollderella 23:25, 27 October 2005 (UTC)[reply]

Medicine: Nursing

What are the Main Focal points when detemining Input/Output (I/O) data of a client?

You'll have to figure out what a "main focal point" is; it sounds like nursing jargon with which I'm not familiar (sorry), and infer from context whether "input" and "output" are referring to process or to fluid balance sheets, but assuming your question refers to fluid balance, when charting inputs and outputs, the following are some of the main considerations:

Intake
- oral intake of fluids
- fluid content of solid food
- intravenous fluid
Output
- urine volume (including that lost incontinently and thus not measured)
- fluid lost via perspiration (usually estimated)
- fluid lost in vomitus (both measured and lost)
- fluid lost in diarrhea and feces/ostomy output
- output from surgical drains
- fluid aspirated via nasogastric tube suction
- volume lost in dialysis
- volume lost as water vapor in respiration (usually not charted)
- loss of blood volume via hemorrhage (including into dressings)

In general, charted inputs and outputs are quite inaccurate and must be supplemented by daily weights when the information is actually needed. In a healthy adult, output is 62% urine, 19% via skin, 13% via lungs and 6% in feces. - Nunh-huh 03:19, 27 October 2005 (UTC)[reply]

Anabolic Steroids

How do anabolic steroids work? How do they effect the cells and muscles of the human body?

Anabolic steroids are a type of steroid hormone. They pass through the outer membranes of many types of cells, interact with a cytoplasmic receptor for androgens and perhaps other receptors as well. The bound steroid-receptor complex moves into the nucleus of the cell, where it binds on certain target areas of the chromosomes, where it alters transcription of certain DNA sequences called genes. Activation of certain genes and inactivation of others results in a variety of changes of cell metabolism. Many of these changes involve increased rates of synthesis of various structural proteins such as those in cartilage and bone, certain functional proteins such as those in muscle, and certain protein hormones such as growth hormones. The net result is a stimulation of processes we call anabolic and a slowing of many processes we call catabolic. The anabolic processes tend to induce growth and enlargement of sensitive tissues and organs, or increases in density or strength. Does that answer your question? alteripse 04:12, 27 October 2005 (UTC)[reply]

peanut oil

what does the expiry date in peanut oil refer to - it getting rancid? if i wanted to use this expired oil as a massage oil is it safe? pls. enlighten. corina202.128.35.13 04:56, 27 October 2005 (UTC)[reply]

The expiry date on peanut oil only refers to the last date it can be sold. It has only a slight relation to its rancidity. Its supposed to be usable for a while after the expiry date, but the rancidity depends on the storage. If its kept refriderated, like all oils, it will react with oxygen at a slower rate, and be usable for long after the expire date. If it is kept in direct sunlight, it will oxidate much faster, and will most probibly be rancid before the expire date.]

NOTE: Food oils become rancid much earlier than you smell them. Artoftransformation 03:48, 27 October 2005 (PST)

It's probably safe to use rancid peanut oil externally, but, please, if you value the person you are massaging as a friend or client, don't. Trollderella 17:09, 27 October 2005 (UTC)[reply]

increase count in RBC

sir,

i would like to know about the chemical responsible for increase in RBC count after taking hygrophila spinosa preparation ,a medicinal plant which is semi aquatic.i would like to know whether the main component has been seperated yet or not.

thanking you

The only research paper indexed in pub med is PMID 11491586. This rat study from India found evidence of ability to raise the RBC count, but did not identify the specific substance responsible. I would infer from the wording of the abstract that as of 2001 the substance had not been identified. It also seems likely from the absence of follow-up papers since 2001 that the "haematinic effect" has not been reproducible in people, but I might be wrong of course and some major drug company may be in the secretive phase of investigating a potentially profitable protein. alteripse 11:46, 27 October 2005 (UTC)[reply]

A curious birth trait: veiled babies

I have searched wikipedia and I have also used search engines to try to answer this question. I am very curious to know any information (and images) that can be given about veiled babies. From what little I've been told, there are some babies who are born with a thin layer of skin covering their faces (called a veil). These babies are also supposed to be gifted psychics. My questions are: Where can information on this birth trait be found? What is the correct medical term for this condition? How often are babies born with this condition? --209.165.134.49 05:25, 27 October 2005 (UTC)[reply]

Your first stop: see caul. -- Toytoy 11:32, 27 October 2005 (UTC)[reply]

You are referring to a bit of folklore, called being "born with a caul." A caul would be a bit of the amniotic membrane that is ruptured during labor. An infant born with a largely intact piece of the amnion is referred to in the obstetric literature as being born en caul. See for example PMID 16035444 and PMID 12052593. Here is a picture. alteripse 11:45, 27 October 2005 (UTC)[reply]

Transparent GIFs / PNGs

I want to make the background of an image transparent. Can I make transparent images using any combonation of the following programs?

MS Paint
Microsoft Word
Microsoft Powerpoint
Microsoft Picture Manager
Corel Draw

I am able to load such images into these programs, can I do it with these programs or do I have to shell out my $80 - $600 USD for fancy programs like Adobe Photoshop and/or Illistrator? — Kjammer ⌂ 05:47, 27 October 2005 (UTC)[reply]

Corel PhotoPAINT should be able to do this (included with the CorelDRAW suite). Otherwise the the GIMP. --R.Koot 06:18, 27 October 2005 (UTC)[reply]

Silly me, I forgot about the GIMP, It is on my Knoppix disc. Thank you for your help (it would've taken me weeks to figure this out.) — Kjammer ⌂ 07:53, 27 October 2005 (UTC)[reply]

Definition of mean curvature

Dear Sirs,

Your web-site mentions 2 definition of mean curvature for e.g. a 2-surface embedded in 3-space i.e.

H = (k_1 + k_2)/2 the average of the principal curvatures k_1 and k_2

but also, to within a constant:

H = div (n) where n = grad f/|grad f| for a hypersurface defined by f(x_1,x_2...x_n) = 0

My question

How do you establish the equivalence between these two formula?

[ Hint: start with the def of gradient ]Artoftransformation

A reference would be appreciated!

Thanks in advance

best wishes

Tony Scott RWTH-Aachen Germany

It looks like that the first formula is a emperical formula, ( for calculating and evaulaiting functions of (x,y,z..) or (r,θ,) and the second formula it its equivalent in Vector form. The relationship of these, of corse would be to calculate the Normal Vector of the curvature of the surface. It would hold that you can calcuate them for any hypersurface, provided that they are partialy diffrentiable in the direction of the gradient. ( note carefully, that the vector quanty grad f/|grad f| Either is positive or negitive ( that is the curvature is either convex or concave )and not infinte or undefined. Another access would be to start with the definition of the gradent in emperical form. ( The proof of the existance would be an advanced calculus subject. )

Refrence's would be both [MathWord def: Mean Curvature ] and for a 2D curve in 3 space, would be the 3rd section of any college calculus text such as: Anton or a petecular favrote: Larson and Holister. Note that, MathWorld has EXCELLENT refrences at the end of their articles.

A simple test of all this undeciperal gibberish would be to work with the top and bottom of unit sphere, the top half would have a constant mean postive curvature over its surface(convex), and the bottom would have a constant mean negative curvature over its surface (concave), and extend it to unit hyperspheres in higher order spaces.

Artoftransformation

Space required by a bit of infomation

How much space does it take on a PC to store one bit of information? -EnSamulili 08:45, 27 October 2005 (UTC)[reply]

The answer depends on the form of knowledge representation you want. Ancheta Wis 09:59, 27 October 2005 (UTC)[reply]

Assuming that you are asking about a minimal representation, then an old text editor program like edlin consumes 12.3 KBytes. The typical block size for a current PC is 1/2 to 1 KByte. Thus the minimal size for a file will be 1/2 KByte. So the overhead consumed to store that one bit of information would be 12.8 KBytes. In the old days of computing this was a real consideration. Today 1 bit on a 1GByte PC would cost less than a billionth of the cost of that PC and can be neglected for all practical purposes, when a 100GByte external drive is a commodity item these days.

After two consecutive edit conflicts (hell, you guys are fast): Depends on on which medium it's stored. Assuming you mean surface area, on a chip these days you get about 1 GB on 1 cm² (very rough estimate), so that's (10^-4 m²) / (8 x 2³⁰ bits) or roughly (10^-4 m²) / (10¹⁰ bits) = 10^-14 m². For size in space multiply this by the thickness of the chip (or just the etched layer?). To this the encasing and connections might have to be added, depending on what exactly you want to know. A similar calculation might be done with a hard disk or optical disk or tape or whatever. But I'm going to eat now (irritating how these daily things can get in the way of having fun here). Of course, one may wonder if a bit exists if it can't be accessed (does something exist if I can't see it?), so you might have to add the hardware needed for that too (including some sort of monitor). DirkvdM 10:17, 27 October 2005 (UTC)[reply]

Thank you. I'm sorry I wasn't clear enough to say that physical space (3D) was the space I am interested in. Your calculation was exactly what I wanted to know, but could you help me with telling what the thickness of a typical chip or an etched layer is. -EnSamulili 12:42, 27 October 2005 (UTC)[reply]

Well, a chip or integrated circuit is roughly 2 mm thick (just look at one inside a computer), but that also includes the encasing. The Semiconductor fabrication article says the wafers on which the chips are produced are 0.75 mm thick. What is used in the first steps is photolithography, which uses nanolithography, so I'd say the etchings would be in the order of nanometers thick. So if you multiply by 'a few times' 10^-9 and round that up for safety you'd get 10^-22 m³. Remember this is all based on a lot of assumptions and guesswork, so take it for what it's worth. If I'd add 'give or take a factor 100' I shouldn't be too far off target. Does Wikipedia have something like an 'accuracy disclaimer'? :) DirkvdM 15:20, 27 October 2005 (UTC)[reply]

With accuracy like that, you're almost guaranteed work as an astrophysicist... Shimgray | talk | 13:12, 28 October 2005 (UTC)[reply]

I hope this is not meant to insult astrophysicists. :) DirkvdM 10:24, 29 October 2005 (UTC)[reply]

Why is the night sky always lighter during a thunderstorm?

Even if there's no lightning. It always seems tinged slightly pinkish and very light, as though it were only just after the sunset.

The phenomenon is called skyglow ☢ Ҡieff⌇↯ 13:34, 27 October 2005 (UTC)[reply]

The skyglow link talks mainly about the effect of electric lighting in cities.

Yes, but that's the cause of the glow. In remote areas, where there are no artificial lights, the sky doesn't glow at all when it's cloudy\stormy, it's just all completely dark except for the lightnings. ☢ Ҡieff⌇↯ 16:58, 27 October 2005 (UTC)[reply]

That's usually the source of apparently brighter skies on cloudy nights; clouds reflect city light back down far more efficiently than the open sky. (Of course even the very inefficient scattering of city lights by normally-low levels of atmospheric dust and water vapour is sufficient to obliterate faint astronomical sights.)

On a cloudy or stormy night far from artificial lights, it gets really dark in my experience—one no longer even enjoys the benefit of starlight by which to see. TenOfAllTrades(talk) 15:13, 27 October 2005 (UTC)[reply]

A. muscaria

In the Amanita muscaria entry a death from an american species of A. muscaria is referenced. I am unable to find this in the medical literature and am hoping the original author (or someone else) may have a source.

Thanks158.111.4.26

A canadian website lists active ingredient LD50 = 3mg/kg (a dose that kills 50% of people) at about 10 mushrooms. You can get to a lethal dose with less, much less. Eating half the LD50, doesn't mean you are safe, like any poison, only none is safe, you can still get sick go into a coma or have fatal convulsions. This amount of active poison will vary wildly with the mushroom growth and season. Only use the fly-agaric to kill flies. It is not a good choice for recreation.

It is a simple error to mistake other species for this species. [26] Do not try eating these mushrooms, if you screw up you are screwed. Many wives tales and drug folklore are untrue, and you do not want to stake your life on them. Let me repeat. Only use the fly-agaric to kill flies. Please wash your hands after handling them. Dominick ^(ŤαĿĶ) 19:20, 27 October 2005 (UTC)[reply]

Thanks--Was not planning on eating it--just trying to track down the source in the medical literature (case report in XYZ journal, for instance) to back up the statement that a human death was attibuted to it. The literature is full of case reports of bad side effects but I can't find a veridied report of death. Anyone else have any ideas?71.56.39.101

What event lead to the discovery of "lactate"?

I'm taking an IV therapy course and this question was posed to us. I've researched the web and found that Syndey Ringers invented Ringers Lactate but nothing about the event which led to the discovery. Please help. Thank you.

There are several websites that say Carl Wilhelm Scheele found Lactic acid in sour milk. I'm not sure this really means that he discovered lactate. He may have been the first to associate this particular chemical with its name and a particular source/process. --JWSchmidt 17:23, 27 October 2005 (UTC)[reply]

weights

My friends and I are having a discussion about liquid weight. Does 16 fluid ounces equal 1 pound?

A fluid ounce is a measure of volume while a pound is a measure of weight. Whether one equals the other depends on the density of the liquid in question. - Mgm|^(talk) 15:43, 27 October 2005 (UTC)[reply]

Only if the liquid has the correct density (of 1 lb per 16 fl. oz, whatever that comes to in SI units). Since liquids have differing densities, however, the relationship between a fluid ounce and a mass ounce is nothing more than an unfortunate choice of terminology. — Lomn | Talk / RfC 15:43, 27 October 2005 (UTC)[reply]

It's not however completely coincidence, because a fluid ounce was chosen to be approximately the volume of water that weighs an ounce (depending of course on temperature and other things). DJ Clayworth 17:23, 27 October 2005 (UTC)[reply]

Copyright infringement

Okay I know this is a homework question but I really need help on this. I will fail my class if I don't do this and it's due on Halloween! Okay here it is.

Your subject is copyright infringement. Now find one person or groups of people whom have been caught doing copyright infringement. Find at least 3 examples. Note the following:

What specifically they were caught doing.
How were they caught doing it?
Did they receive large fines? If so, how much were they?
Did they receive a jail sentence? If so, what was the sentence and how long was it?

If you could help me that would be great. Thanks!--63.199.33.66 16:49, 27 October 2005 (UTC)[reply]

You might start by looking at Wikipedia:Copyright problems. Or Software piracy. If you think about ways in which people might violate copyright laws it shouldn't be hard to come up with ideas for people who have broken them. DJ Clayworth 17:20, 27 October 2005 (UTC)[reply]

Figure out is copyright infringement is a criminal offense in your jurisdiction (this varies). If you cannot do this, you deserve to fail. Physchim62 18:14, 27 October 2005 (UTC)[reply]

It sounds like your class is using one of those lesson plans provided by the music industry, teaching children not to copy music (e.g. homework = finding people who went to jail for running Kazaa). What's the class actually like? Ojw 21:15, 27 October 2005 (UTC)[reply]

What we do is this: We sit around while the teacher gets definitions ready, and play's on his laptop. He takes cell phone calls and leaves us sitting there before we can log onto our computers and do work. We do endless projects we've done 7 projects since the start of the year, and get about 3-5 hours total (Sometimes less) and we do typing for 1 hour every week. Half of our grade is usally on how we name the file, and put it in his grading folder. We have a VERY bad technology teacher, and class. This should answer your question Ojw--63.199.33.66 16:28, 28 October 2005 (UTC)[reply]

"Figure out is copyright infringement is a criminal offense in your jurisdiction (this varies). If you cannot do this, you deserve to fail." What do you exactly mean by this? "Figure Out is Copyright" Are you trying to say "Figure Out what Copyright is" makes since. 63.199.33.66 17:14, 31 October 2005 (UTC)[reply]

I got one extra week but still I would like help--63.199.33.66 17:20, 31 October 2005 (UTC)[reply]

Your best bet would be to run a search on Slashdot. Copyright complainers tend to gather there.--Fangz 21:43, 31 October 2005 (UTC)[reply]

Birthday probability question

This came up at my conscientious objector place. We know that if there is a group of over 365 people, at least two people will have the same birthday. But if we pose the question "backwards", i.e. how large a group of people has to be so that every day of the year is a birthday of someone? The correct answer, of course, is "infinite", as there is nothing preventing, for example, everyone from being born on the same day.

But given the number of people, what is the probability of every day in the year being someone's birthday? For 1 to 364 people, it is 0, i.e. such a thing is impossible. For exactly 365 people, it is 1/(365!), i.e. 1 divided by the factorial of 365. But what is the probability for larger groups? (For simplicity, we ignore leap years.) — JIP | Talk 16:38, 27 October 2005 (UTC)[reply]

This section is getting pretty long, so I've moved it to Wikipedia:Reference desk/Science/Birthday probability question. The short answer seems to be

P(m,n)=\sum _{k=0}^{n}(-1)^{k}{n \choose k}\left({\frac {n-k}{n}}\right)^{m}

where m is the number of people and n the number of possible birthdays (= 365). —Ilmari Karonen 01:22, 28 October 2005 (UTC)[reply]

Unix command question

I know the head and tail commands give me the N first or last lines of a text file. But how can I get all the lines except the N first or last ones? — JIP | Talk 17:44, 27 October 2005 (UTC)[reply]

man head and man tail should help you. Specifically, you want head -n -N and tail -n +N+1, where N is the number of lines to skip. Ilmari Karonen 19:08, 27 October 2005 (UTC)[reply]

Internet Explorer breaking

Hello. So my gimpy old computer is messing up every time I try and start Internet Explorer.

A "Microsoft Visual C++ Runtime Library" message pops up, telling me in a pleasingly jolly manner that there's a "Runtime Error!" and "R6016 - not enough space for thread data".

What the heck does this mean, and how the heck do I stop it. Once I OK this, and then the 'Internet Explorer is shutting down' message (even though it hadn't yet started up), IE then starts up fine without me clicking anything else.

It's IE version 6, and, um, I'm still on Windows 98. *shame*. Programs I see running when I press ctrl-alt-del are Internet Explorer, Explorer, Msnmsgr (despite me trying to close it, it won't let me, cause a hotmail window is open in IE), Atdialler1 (yes, I'm connecting on a modem, too), msnappau, Loadqm, Systray, E_s10ic2 (think this is my printer app) and Rnaapp.

Please, clever Wikipedians, help a brother out. Proto t c 17:57, 27 October 2005 (UTC)[reply]

File:Firefox logo 305x150.png

Get Firefox --Quasipalm 21:02, 27 October 2005 (UTC)[reply]

I already have Firefox. This is not what I asked. I asked for help fixing IE. *expletives deleted* Proto t c 22:32, 27 October 2005 (UTC)[reply]

Might be a virtual memory problem... how much space do you have left on your hard drive? Try deleting unnecessary files and uninstalling unused applications. Check your virtual memory settings as well. --Canley 00:14, 28 October 2005 (UTC)[reply]

This isn't what you want to hear, but try installing Linux! Seriously though - what version of ie are you using? Have you tried reinstalling it? I think you can download it. Trollderella 23:24, 27 October 2005 (UTC)[reply]

Given the message you're getting, trying Canley's suggestion may be worth a go. - 131.211.210.11 07:17, 28 October 2005 (UTC)[reply]

Excuse me for flogging a dead horse, but given the amount of problems people seem to have with IE (and msWindows in general) I wonder why people insist on keeping on using it. DirkvdM 07:32, 28 October 2005 (UTC)[reply]

I'll try and figure out my virtual memory. Trollderella - version 6.0.something. I will reinstall it. Dirk - most people go on using Windows because it's user friendly. Yes, it has security and bug issues, but it's a heck of a lot easier for the layman to use than Linux or whatever. Ditto IE. Linux doesn't have as many problems because a) a lot less people use it, and b) The people that do use it are technically adept. If the same number of users (and with that, the same level (or lack of) technical knowledge) had Firefox and Linux as do those with IE and Windows, then I dare say there'd be just as many problems with those two programs. Everyone else, thank you for your help. Proto t c 12:15, 28 October 2005 (UTC)[reply]

Linux is not the only Operating System beside msWindows. Mac's are actually quite known for their user-friendliness. But I was mainly referring to browsers. Of course many more people use IE than other browsers, which is why there will be more postings about it, but why not install a bunch of them (most are for free) and switch if one gives you problems? Easy as pie. Or do you have a specific reason to use IE? The only one I can think of is when you are a webdesigner and have to test your 'designs' on all (mqin) browsers (which is done waaaaay too little, by the way)? DirkvdM 09:53, 29 October 2005 (UTC)[reply]

Watching a DVD image file?

Is it possible to watch a dvd image file without actually burning it to a disc? For what it's worth, it is a nero image file. Thanks!!

Yes it is, and not just DVDs, but any disc image. All you need is to create and mount a virtual drive using a special program. I suggest Daemon Tools ☢ Ҡieff⌇↯ 20:51, 27 October 2005 (UTC)[reply]

endangered animals

What endangered bird flies 2 miles south in Winter?207.200.116.202

Why would we do your homework for you? --Quasipalm 21:00, 27 October 2005 (UTC)[reply]

Graying hair

Why doesn't hair gray uniformly. That is, why do sideburns tend to gray before the hair on the top of the head, instead of uniformly (randomly) all over the head. Are those hair follicles different? --Quasipalm 21:07, 27 October 2005 (UTC)[reply]

You are correct: there are differences between hair follicles and surrounding skin cells and growth signals in different parts of the body. Why doesn't hair grow uniformly on all areas of the body? Why isn't hair on all parts of the body equally sensitive to androgens? The answer to the first question (about growth) is likely to involve many different factors, while the answer to the second (about androgen sensitivity) is likely to invole only a couple, but both are examples of bodywide differences in hair growth. My hunch is that graying is more like the limited number of factors influencing androgen sensitivity but we don't know what they are as well. alteripse 10:07, 28 October 2005 (UTC)[reply]

Battery power

Why do batteries seem to regain a portion of their power after not being used for a period of time. Shouldn't the power be at the same level as it was when last used? --Quasipalm 21:09, 27 October 2005 (UTC)[reply]

Batteries produce power through an electrochemical reaction. In general, such reactions can involve multiple processes, not all of which necessarily run at the same speed. As the battery runs down, the slowest of these processes become the limiting factor for the power output. When you unplug the battery, these slower processes continue to run as the battery gradually returns to chemical equilibrium. Thus, when you plug it in again, the overall reaction can run faster (and thus produce more power) for a while, until the slowest processes become a bottleneck again.

As an analogy, think of a bottle of shampoo (or ketchup or any other viscous liquid). When the bottle first runs out, there's still quite a bit of shampoo stuck to the sides of the bottle. If you leave the bottle standing upside down for a while, however, the shampoo slowly flows down the walls, enabling you to squeeze a little more of it out of the bottle. Ilmari Karonen 23:29, 27 October 2005 (UTC)[reply]

What if?

What would happen if someone added a template to the end of their signature?--Lapsed Canadian 21:44, 27 October 2005 (UTC)[reply]

It seems I can answer my own question--Lapsed Canadian 21:51, 27 October 2005 (UTC)[reply]

Well, it puts extra load on the servers for one thing. Take a look at Wikipedia:Transclusion costs and benefits--Commander Keane 01:09, 28 October 2005 (UTC)[reply]

Long story short, if you must do it, use {{subst:templatename}} instead of just {{templatename}} -- it'll put less burden on the server. Or, you could be a Wikipedia hero and just not use them at all… Garrett Albright 04:18, 28 October 2005 (UTC)[reply]

October 28

Lipofuscin,dementia and age spots

What is the chemical formula of lipofuscin and is it the same chemical involved in dementia and age spots.

If known what causes its production?

Richard

The article on lipofuscin has some of the answers that you seek. Dismas|^(talk) 00:47, 28 October 2005 (UTC)[reply]

Lipofuscin can accumulate in many cell types but I do not think it is specifically associated with age spots; they seem to be due to uneven distribution of melanin. Some neurodegenerative disorders have been associated with lipofuscin accumulation. Lipofuscin is not a single chemical; here is a more detailed article about a major retinal lipofuscin associated with macular degeneration: Biosynthesis of a major lipofuscin fluorophore in mice and humans with ABCR-mediated retinal and macular degeneration. There have been attempts to find associations between Alzheimer's disease and lipofuscin, but I don't think links have been demonstrated. --JWSchmidt 04:53, 28 October 2005 (UTC)[reply]

white blood cells

Has there been any scientific studies that prove a positive reaction to building white blood cells in an aging male? For example: taking a certain vitamin?

Thank you,

Sandra Crosson

— Preceding unsigned comment added by 71.244.229.60 (talk • contribs)

Can you rephrase more clearly?

I don't understand what you mean by building: increasing the number of white cells or making them different in some way?

I don't understand what you mean by positive reaction: a detectable effect of building white blood cells or a detectable beneficial effect of building white blood cells?

Are you asking if taking a certain vitamin increases WBC count?

Are you asking if it is beneficial to increase the number of WBCs?

You are aware that too few WBCs are bad and too many WBCs are bad? That making more if you have too many is not necessarily beneficial? That there is no demonstrable advantage to having a WBC count of 9,000 per mm3 instead of 8,000 in a healthy person? alteripse 03:20, 28 October 2005 (UTC)[reply]

Restorative Dentistry

What does "recement" mean? It is in benefits lists for dental insurance, and used in the context of "recement crown", "recement inlay" or "recement cast".

--64.174.7.191 03:16, 28 October 2005 (UTC)[reply]

At a wild guess, try reading as "re-cement", or "apply cement to [a crown, inlay or cast] a second time". Notinasnaid 07:18, 28 October 2005 (UTC)[reply]

The word "recement" means exactly what it literally says. Dental restorations--that is to say, devices used to re-construct the shape and form of a damaged tooth (i.e., fillings, inlays, crowns, or veneers) often (but not always) need to be cemented to a tooth in order for them to be reliably retained in place. However, they don't always stay in place forever. The combined action of salivary dissolution and repetitive chewing force can cause disintegration of the luting cement over time, leading to loosening and displacement of the restoration. If there is no significant damage to the tooth by decay and the restoration still fits, it can be recemented in its proper position.

Whether a dental insurance policy pays a benefit for a recementation procedure depends on the provisions of the policy. However, most dental insurance carriers would much rather pay for a low-cost procedure such as a recementation than pay for an expensive replacement of an otherwise serviceable dental restoration. In the U.S., the insurance industry and the American Dental Association have collaborated on a set of procedure codes, and there are codes for recementation, giving the technique official recognition. --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 18:49, 28 October 2005 (UTC)

GPS Protocols

No-where on the internet can I find any reference of an NMEA protocol to Garmin protocol converter. Does such a thing exist ? What I am actually seeking to do is to use my GPS receiver (NMEA protocol) to find my location on Google Earth (which only uses Garmin / Magellan inputs). Any joy anyone please ? Thanks so much--jrleighton 03:42, 28 October 2005 (UTC)

(moved from Wikipedia Talk:Reference desk by Garrett Albright 04:09, 28 October 2005 (UTC)[reply]

Interesting question. This document about the NMEA standard describes the NMEA protocol (for the benefit of the nautically challenged, NMEA is a standard interface for transferring navigational information between electronic devices on boats). It looks like it's implemented on stop of some very standard serial communications protocols, so it should be very straightforward to build a gadget that speaks and understands NMEA. As to speaking the Garmin/Magellan protocol, I don't know if the protocol is public. It probably wouldn't be difficult to reverse engineer, however. However, given that GPS units are incredibly cheap these days, by the time you've purchased all the components to build a converter it may have been cheaper just to buy an appropriate GPS; which is probably why you can't buy a Magellan protocol to NMEA protocol converter!--Robert Merkel 06:18, 28 October 2005 (UTC)[reply]

science / history

Why do different science disciplines not cross reference each other? Hence we seem to end up with only 20,000 years of human history but the globe being populated by man crossing land bridges that existed millions of years ago and no-one in the science community questions this.

I'm not sure what the problem is with that. It is frequently accepted that man has been around a lot longer than modern history has records (which means history goes back around 5200 years), and that none of the early histories came down to us. What was happening before that is interesting, and studied as prehistory. What should the science community be questioning? Notinasnaid 08:02, 28 October 2005 (UTC)[reply]

Landbridges did not only exist "millions of years ago." The Bering land bridge, which connected Siberia and Alaska, was in existence 22,000 - 7,000 years ago, well within the "20,000 years of human history" that you have cited. I agree with Nitinasnaid: I don't think I understand your point. If it is that different scientific disciplines don't overlap and cross-reference one another, I think you are mistaken. Neuroscience and biochemistry are two good examples. So is geology, which borrows from physics, biology, and chemistry, among other disciplines. If your point is that the wisdom found in history and science are mutually exclusive, I have to disagree. -Parallel or Together? 08:12, 28 October 2005 (UTC)[reply]

I accept weather changes geography in much shorter time scales than geology, but everything I have read indicates Africa is the cradle of humanity but Australia has the oldest tracable records of mankind and links to Australia severed through continental drift, not climate change.

Modern Homo sapiens came to Australia between 40,000 and 60,000 years ago by land bridges and perhaps small-distance sea crossing (see Prehistory of Australia). On the other hand, Homo sapiens appeared in Africa around 200,000 years ago (see Human evolution). Humans may have migrated from Africa to Australia in that span of 140,000 years (this is the single-origin hypothesis). Or Homo sapiens may have independently evolved in different areas of the world from the local Homo erectus populations, who themselves had migrated out of Africa many thousands of years before (this is the multiregional hypothesis). Does this help or did I misunderstand you again? (if so, I apologize). -Parallel or Together? 09:13, 28 October 2005 (UTC)[reply]

Helpfull - Thank you.

You left out the alien contact hypothesis made famous by von Däniken. Aliens carried man all over the globe! If it wasn't for those meddling aliens, we would have gotten away with it too... Dominick ^(ŤαĿĶ)

Haha, you are right. This was a significant oversight on my part. Please forgive me. -Parallel or Together? 14:10, 28 October 2005 (UTC)[reply]

One thing that should be clarified is that the sub-species homo sapiens sapiens refers to modern humans, while the species homo sapiens also includes ancient humans, such as Homo sapiens idaltu. StuRat 17:01, 28 October 2005 (UTC)[reply]

White blood cell

How does the body get rid of WBC??? What i mean is that RBC are destroyed in the spleen and liver, so where are the WBC destroyed??? And also why do RBC do not have nucleus, by having one it can increase its lifespan, why not???

Thank you for you time...:)

The average life-span of neutrophils is about 11-16 days, most of which is spent maturing in the bone marrow. About 24 hours after they are released into the circulatory system, they undergo apoptosis and are phagocytized by other cells. As for RBCs, you probably know that some animals normally have circulating nucleated RBCS, but that most mammals, including humans, don't. Mammals have smaller end-vessels in their circulatory systems: small enough that RBCs must be able to be deformed (squeezed) to pass through them - easier if they are smaller and enucleate. In addition, an RBC with no nucleus can contain a higher hemoglobin concentration and therefore carry more oxygen. - Nunh-huh 16:53, 28 October 2005 (UTC)[reply]

Factorial

Could someone please explain how to calculate decimal factorials (ex. 7.35! or 3.9!)? I found the explanation at Factorial a bit confusing. Don Diego ^(Talk) 16:16, 28 October 2005 (UTC)[reply]

In general, you have to calculate the Gamma function for the argument plus one. This isn't particularly easy, so you're better off looking up the result in a table. --Bob Mellish 16:31, 28 October 2005 (UTC)[reply]

Basically, to get n! you have to evaluate $\int _{0}^{\infty }x^{n}e^{-x}dx$ $\int _{0}^{\infty }x^{n}e^{-x}dx$ . I doubt there's an easier way, except for certain specific values. —Keenan Pepper 17:11, 28 October 2005 (UTC)[reply]
- Note that that's actually how you calculate (n-1)!. Incidently, Window's Calc.exe will cheerfully handle non-integer factorials. --Bob Mellish 19:03, 28 October 2005 (UTC)[reply]

No, that's n!. The gamma function is shifted by one, but the integral I gave is not.

—Keenan Pepper 19:29, 28 October 2005 (UTC)[reply]

Ah yes, I see now. Sorry. --Bob Mellish 23:21, 28 October 2005 (UTC)[reply]

- There are easier ways than evaluating the the integral directly. I have written a 15-line implementation of Lanczos approximation for the Gamma function in Python which is currently available at the Swedish Wikipedia. The Gamma function is implemented by pretty much any decent mathematics software, and there is also an online arbitrary-precision calculator at http://oldmill.uchicago.edu/~wilder/Code/hpgamma/. Not much hope calculating it by hand, though. Fredrik | talk 19:28, 28 October 2005 (UTC)[reply]

Ooooh - this caught my attention. I didn't know that there was such a thing as a "Lanczos approximation" outside of quantum mechanics! Another score +1 for the RD :-) --HappyCamper 03:54, 29 October 2005 (UTC)[reply]

Direction of data on CDs

Does the data on a CD start at the outside and go inward, like a vinyl record, or vice versa? Clockwise or counter-clockwise? What about DVDs? Are there any media that go the "wrong" way? —Keenan Pepper 17:15, 28 October 2005 (UTC)[reply]

It goes inside and out, as you can verify by looking at a blank CD-R and one that's partially full. As for the direction, that would be clockwise (assuming you're looking at the data side of the disc), as that's the direction a CD spins in a CD player. --Pidgeot (t) (c) (e) 18:40, 28 October 2005 (UTC)[reply]

There is also plenty more information on compact disc that's worth looking at :) ☢ Ҡieff⌇↯ 20:00, 28 October 2005 (UTC)[reply]

I've heard that Gamecube discs have the data track spiraling the opposite direction; I'm not sure if they record it from the outside in, or if the disc actually rotates in the opposite direction. --David Wahler (talk) 20:01, 28 October 2005 (UTC)[reply]

You wouldn't have to spin it backwards to record, you could just reverse the order of the bits when recording it. It would be interesting to find out if they do this though, it would certainly make piracy harder. --Quasipalm 21:20, 28 October 2005 (UTC)[reply]

A GameCube disc isn't all that different from a regular disc, they just use a proprietary filesystem and disc structure that a regular DVD drive can't read. It doesn't spin "the wrong way" around. (If it did, I'd imagine it would have been a nightmare to make the Panasonic Q work.) --Pidgeot (t) (c) (e) 21:48, 28 October 2005 (UTC)[reply]

birds

how many species of birds are there? - anon

Second paragraph of Bird. ;) —Keenan Pepper 19:32, 28 October 2005 (UTC)[reply]

Lymph Nodes

can someone please tell me how many Lymph Nodes are under you left arm.

Thanks Sue M.

Sue, there is no specific number of lymph nodes in the left armpit (these would be called left axillary nodes, by the way). The number differs from person to person, from very few (less than five) to more than thirty. One study (in women with breast cancer) showed an average of about 10 lymph nodes per axilla. - Nunh-huh 21:36, 28 October 2005 (UTC)[reply]

Potential Energy/ Kinetic Energy/ Conservation of Energy / Linear Momentum

What is the exact mathamatical relationship between momentum, initial momentum, final and change in energy? conservation of energy? thank you--152.163.101.12 21:08, 28 October 2005 (UTC)[reply]

$p=mv$ (momentum is mass times velocity)
$I=mv-mu$ (Impulse is change in momentum)
$I=Ft$ (Impulse is force times time)
$E=0.5mv^{2}$ (Energe is half mass times velocity squared)

Conservation of energy is just "Energy cannot be created or destroyed", it can only be converted into other forms of energy. For example, an object falling loses gravitational potential energy and gains kinetic energy. Heat, sound, gravitational potential, elastic potential... the list goes on. But it's all conserved. Deskana 22:09, 28 October 2005 (UTC)[reply]

However, note that Einstein taught that energy alone is not always conserved, nor mass alone, but both are conserved in accordance with

E=mc^{2}

. Mass is regularly changed to energy, in the Sun, in nuclear reactors, in nuclear weapons, and in radioactive minerals. Energy can also theoretically be changed into mass, although we haven't found a way to do so yet. Of course, in normal (non-nuclear) reactions, the conservation of energy is perfectly valid. StuRat 00:54, 29 October 2005 (UTC)[reply]

Actually, energy gets converted to mass all the time—for instance, a pair of photons producing a particle-antiparticle pair. And if I recall correctly, even in ordinary energy transfers, a tiny amount of the energy causes the mass to increase by a tiny amount (even in heat transfers or chemical recations)...but I could be wrong about that. In any case, I think that for the purposes of the principle at least, mass can be regarded as a special form of energy, and conservation of energy still holds. Note that it may not hold on short time scales in quantum mechanics. — Knowledge Seeker দ 04:30, 29 October 2005 (UTC)[reply]

It actually does hold, always, provided you define "energy" in the right way. ;) More specifically, even on short time scales in quantum mechanics, physicists assume conservation of energy and allow virtual particles to have the "wrong" mass; this is often explained instead as an energy-time uncertainty principle, but that's probably less accurate. -- SCZenz 22:10, 29 October 2005 (UTC)[reply]

October 29

Porous Steel?

When Steel is boiled in water does it have pores which open up to absorb? Such as when traps are boiled in Walnut hulls or logwood dye and they take on a darker color. The question is does steel have pores?

The only increase in "pore" size you wuold have would be the expansion of the steel and thus the increase of intermolecular distances. So no, steel doesn't have pores. --Borbrav 00:30, 29 October 2005 (UTC)[reply]

Darkening of steel after boiling with plant extract would be a result of either staining or oxidation. alteripse 00:42, 29 October 2005 (UTC)[reply]

Always something new: Porous Steel. --JWSchmidt 23:20, 29 October 2005 (UTC)[reply]

Silverwing

If you've ever read the Silverwing series of books you know that there are two species referenced called the Silverwing and Brightwing bats. A lot of the other species seem to be based on real ones, so does anyone know what Silverwings and Brightwings could possibly be in real life? Thanks for the help! ♥♥purpl e feltangel ♥♥ 00:48, 29 October 2005 (UTC)[reply]

By the way, Silverwings are said to have short, broad silver wings and short tails, while Brightwings have long, narrow wings, bright fur, and "elegant" ears. ♥♥purpl e feltangel ♥♥ 06:53, 29 October 2005 (UTC)[reply]

It sounds like it could be a species of moth, perhaps even tropical moths. Does this help? --HappyCamper 11:52, 29 October 2005 (UTC)[reply]

Uh, they're bats. :D I'm asking what bat species they are. ♥♥purpl e feltangel ♥♥ 21:34, 29 October 2005 (UTC)[reply]

Quote from author here [www.kennethoppel.ca]:

"All my characters are based on real species of bats -- even Goth and Throbb! Shade's a silver-haired bat; Marina's a red bat, Goth is something called a spear-nosed bat, also known as the Vampyrum Spectrum. Cama Zotz is based on a real Mayan bat deity of the same name. I also wanted to pick names that seemed appropriate for flying creatures. So I used the names of some angels (Cassiel, Ariel), the names of special winds (Zephyr, Chinook, Scirocco -- you can look them up!) and mythic heroes (Icarus). As for Shade, his name just reminded me of shadows and twilight. Marina means "of the sea" -- she lives on an island as the story begins. And Goth is kind of shorthand for the word "gothic" -- which conjured up all sorts of images of vampires and dungeons"

There you go. Prodego ^talk 21:52, 29 October 2005 (UTC)[reply]

Do rats really eat feces?

More specifically, is dog poop really a significant food source for rats? Even more specifically, if I keep my collected dog poop (individually wrapped in do-do-bags) in an open container in my bushes in Florida and then I see a rat, is the poop likely to be a significant cause of the presence of the rat? Note that some city governments list dog feces cleanup as a critical rat-prevention tactic. They also indicate that rats "spread disease" but I think this fact is also disputed.

Rats are suspected of aiding in the spread of the bubonic plague during the Black Death pandemic... although this fact is indeed somewhat disputed. However, rats are technically cabaple of spreading disease, it is just not proven beyond a shadow of a doubt that they did so in this particular instance. And yes, rats eat their own feces[27] so they might also eat dog feces. -Parallel or Together? 12:35, 29 October 2005 (UTC)[reply]

I would say that if you find the bags have been chewed up with the feces strewn about the container, suspect the rats. If the bags remain undisturbed, I would probably not worry about it attracting the rats. Dismas|^(talk) 04:41, 30 October 2005 (UTC)[reply]

Actually, as I understand it, what is not certain is that the black death was bubonic plague, but the plague is spread by rats. Or, rather, strictly speaking, it's the fleas that live on the rats that infect humans (which is why it's a bad idea to kill rats when there's an outbreak - the fleas will switch to humans). But, more on the subject, coprophagy is a way for rodents to get all the nutritional value out of their food. In the case of rabbits, they have two different kinds of droppings; the ones you get to see are the second kind because the first is eaten. Apparently, dogs also do this, but not (necessarily) for the same reason. So I wonder if dog poo has the qualities (nutritional value) that a rat would be looking for. Then again, the rats might just be plain stupid and not realise that they're doing something useless. Shit happens, so to say. DirkvdM 06:36, 30 October 2005 (UTC)[reply]

What is the most intelligent insect?

Or has nobody really bothered to find out? Kid Apathy 13:20, 29 October 2005 (UTC)[reply]

While nobody knows for sure (as they keep dropping their number 2 pencils when taking standard IQ tests), I would hazard a guess and say bees. Social animals have an inherent need for greater intelligence to communicate with others in their group. In the case of bees, they are known to communicate the location of food via a "dance" performed in the hive. However, insect intelligence is thought to be almost entirely instinct, with very little capacity for true learning. This explains how such apparent intelligence can be packed into such a small brain. Instinctive behaviours require far less brain mass than learning. StuRat 13:26, 29 October 2005 (UTC)[reply]

Take a look at Mushroom bodies. If you want more, try this: Evolution, Discovery, and Interpretations of Arthropod Mushroom Bodies --JWSchmidt 23:11, 29 October 2005 (UTC)[reply]

Depends on how you define intelligence, of course, and that's a tricky one. Any definition will be anthropomorphic. By such a definition you'd be hard put to find any intelligence in insects at all. As StuRat says, insect 'intelligence' is basically instinct. Human intelligence is an ability to adapt to changing circumstances (learning). But this sort of intelligence is not what makes insects tick (no pun intended). There are different ways to be successful as a species. Intelligence is one of them, and it happens to be the one that homo sapiens has specialised in. Other methods are evolution and numbers. Insects as they are may produce so much offspring that some of them will find the right habitat to survive. On top of that, variation will lead to evolution. But humans don't have quite as much offspring and live much longer (making evolution work slower). So they use intelligence (which can be seen as a form of evolution in one individual).

Sturat also mentions bees, but my bet is on ants. Here, however, the intelligence is not in the individuals, but in the 'hive' (what's that called with ants?). Individually, ants are pretty stupid (even working against each other), but as a group they can move mountains (well, create mounds, anyway). DirkvdM 07:05, 30 October 2005 (UTC)[reply]

Bees, ants, yes, but Jiminy Cricket is no fool either. David Sneek 09:19, 30 October 2005 (UTC)[reply]

I think we'd have to define intelligence first, and whether or not we recognize collective or emergent intelligence (which is how the social insects would win) or whether or not we are considering individual intelligence. Ants and bees on the individual level are doing nothing more than following a fairly preset series of commands — it's just that those commands, spread among a few thousand individuals, can create some pretty neat results. I'm not sure how you'd measure individual intelligence in insects (problem solving?) and I'm not sure anyone has tried to. --Fastfission 15:26, 30 October 2005 (UTC)[reply]

One could say that humans are also a collection of (by themselves) stupid cells that only display intelligence when they cooperate. Our cells are just stuck together, whereas ants have the freedom to move around by themselves. But they also have to stick to the collective to survive. Which is sort of a communist (or fascist) society. Which is why communism and fascism will never work; the constituent parts are just too individualistic. Fyi :) . DirkvdM 08:08, 31 October 2005 (UTC)[reply]

I would say ants are likely to be the most 'intelligent', though that is fairly broad as there are hundreds of species. As some species have developed agriculture (of fungi & captured aphids), slavery & warfare. These are pretty strong indicators of intelligence in humans, though not - for the last 2 - of social conscience or morality.AllanHainey 15:25, 31 October 2005 (UTC)[reply]

Related question: Has an insect exhibited tool use? --Fangz 20:57, 31 October 2005 (UTC)[reply]

A division question

I'm having trouble dividing $3x^{4}+5x^{3}-2x^{2}+6x+3$ by $x+2$ . Could someone please show me how so that I can solve the problem and then apply the method I've learned to other, similar problems? Thanks, anon.

That's called synthetic division. See that article for details. StuRat 17:18, 29 October 2005 (UTC)[reply]

On second thought, a better introduction to the material is located at Polynomial long division. StuRat 17:23, 29 October 2005 (UTC)[reply]

The 'do your own homework' thing has made students smarter, I see. :) DirkvdM 07:08, 30 October 2005 (UTC)[reply]

Telnet option 200?

Half curiosity, half pragma (implementing my own telnet option parser for a new MUD codebase), but what does telnet option 200 (C8 in hex) signify for MUDs and MUD clients? Google draws a blank, and it's an 'unofficial' option as far as RFCs and their ilk are concerned. So does anyone know what this does, or shall it be consigned to the pit of obscurity?

The only reference I could find to it is [28], where you can also see another mysterious telnet option: 170. I also found about options 85 (Mud Compression Protocol, v1), 86 (Mud Compression Protocol, v2), 90 (Mud Sound Protocol), and 91 (Mud Extension Protocol). Which client or server is sending you option 200? --cesarb 00:12, 30 October 2005 (UTC)[reply]

I'm seeing it come up on IRE muds, when Rapture is sending the initial option communication, along with 86 (COMPRESS2) and asking if EOR is OK (can't recall the number off hand. Probably nothing, because MUSHclient just says no to number 200, but it's a curiosity. --Sam Pointon 10:53, 30 October 2005 (UTC)[reply]

WWII German Enigma Machine

The WWII German Enigma machine is based on what mathematical models? In other words, what is the primary mathematical basis of the Enigma? Do you know of any websites that provide a discussion of its mathematical basis?--158.80.0.2 19:12, 29 October 2005 (UTC)[reply]

How's about The Cryptographic Mathematics of Enigma from the NSA? --jpgordon ∇∆∇∆ 20:09, 29 October 2005 (UTC)[reply]

biology

why are plants green?

Chlorophyll, the chemical they use to absorb energy from sunlight, is green. -- SCZenz 22:07, 29 October 2005 (UTC)[reply]

Another way to explain that is that chlorophyll absorbs and transduces light of the reddish wavelengths most efficiently, and it reflects most light of green wavelengths. alteripse 22:17, 29 October 2005 (UTC)[reply]

Plants are all "green with envy" that animals get to move around and they don't. StuRat 16:47, 30 October 2005 (UTC)[reply]

Transverse meridional/"great-ellipse" arcradius?

Consider the loxodromic equations:

$VLeg$ = The "vertical" (Δlatitude) "leg";
$HLeg$ = The "horizontal" (adjusted Δlongitude) "leg";

$Azg$ = Graticular (spherical) azimuth;

$HyP_{g}$ = Loxodromic hypotenuse;

$VLeg=\cos \!\left\{Azg\right\}\times HyP_{g}=|\Delta Latitude|;$

$HLeg=\sin \!\left\{Azg\right\}\times HyP_{g}={\frac {VLeg\times |\Delta Longitude|}{\operatorname {arccosh} \!\left\{\sec \left\{Lat_{2}\right\}\right\}-\operatorname {arccosh} \!\left\{\sec \left\{Lat_{1}\right\}\right\}}};$

For the spherical loxodrome:

Azg=\arctan \!\left\{{\frac {HLeg}{VLeg}}\right\};

HyP_{g}={\sqrt {VLeg^{2}+HLeg^{2}}};

For the ellipsoidal loxodrome (referring here to an oblate ellipsoid [ $a>b$ ]):

$a,b$ = equatorial, polar radii;

$\operatorname {M} \!\left\{Lat\right\}=\!\left\lbrack {\frac {a}{b^{2}}}\right\rbrack ^{2}\operatorname {N} \!\left\{Lat\right\}^{3}\quad {\mbox{(Meridional arcradius/radius of curvature)}};$

=k_{1}\,\!

?

$\operatorname {N} \!\left\{Lat\right\}=\!{\frac {a^{2}}{\sqrt {(a\times \cos \!\left\{Lat\right\})^{2}+(b\times \sin \!\left\{Lat\right\})^{2}}}}\quad {\mbox{(Normal/transverse equatorial arcradius)}};$

=k_{2}\,\!

?

$a\times \operatorname {HyP} _{e}\!\left\{Lat\right\}$	$={\sqrt {(VLeg\times \operatorname {M} \!\left\{Lat\right\})^{2}+(HLeg\times \operatorname {N} \!\left\{Lat\right\})^{2}}},$
	$={\sqrt {(\cos \!\left\{Azg\right\}\times HyP_{g}\times \operatorname {M} \!\left\{Lat\right\})^{2}+(\sin \!\left\{Azg\right\}\times HyP_{g}\times \operatorname {N} \!\left\{Lat\right\})^{2}}},$
	$={\sqrt {(\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\})^{2}+(\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\})^{2}}}\times HyP_{g},$
	$=\operatorname {O} \!\left\{Azg:Lat\right\}\times HyP_{g};$

The ellipsoidal loxodromic azimuth has its own relationship set:

$\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\}$	$={\sqrt {\operatorname {O} \!\left\{Azg:Lat\right\}^{2}-(\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\})^{2}}},$
	$=\operatorname {O} \!\left\{Azg:Lat\right\}\times {\sqrt {1-(\cos \!\left\{Azg\right\}\times {\frac {\operatorname {M} \!\left\{Lat\right\}}{\operatorname {O} \!\left\{Azg:Lat\right\}}})^{2}}},$
	$=\operatorname {O} \!\left\{Azg:Lat\right\}\times \sin \!\left\{Aze\!\left\{Lat\right\}\right\};$

Likewise,

$\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\}=\operatorname {O} \!\left\{Azg:Lat\right\}\times \cos \!\left\{Aze\!\left\{Lat\right\}\right\};$

Hence,

\sin \!\left\{Aze\!\left\{Lat\right\}\right\}=\sin \!\left\{Azg\right\}\times {\frac {\operatorname {N} \!\left\{Lat\right\}}{\operatorname {O} \!\left\{Azg:Lat\right\}}};

\cos \!\left\{Aze\!\left\{Lat\right\}\right\}=\cos \!\left\{Azg\right\}\times {\frac {\operatorname {M} \!\left\{Lat\right\}}{\operatorname {O} \!\left\{Azg:Lat\right\}}};

\tan \!\left\{Aze\!\left\{Lat\right\}\right\}=\tan \!\left\{Azg\right\}\times {\frac {\operatorname {N} \!\left\{Lat\right\}}{\operatorname {M} \!\left\{Lat\right\}}}={\frac {HLeg\times \operatorname {N} \!\left\{Lat\right\}}{VLeg\times \operatorname {M} \!\left\{Lat\right\}}};

The point of all this, is that it calls into question the validity of the classically prescribed arcradius at a given latitude, in a given direction:

$\operatorname {O} \!\left\{Azg:Lat\right\}$	$={\sqrt {(\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\})^{2}+(\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\})^{2}}},$
	$={\frac {\operatorname {O} \!\left\{Azg:Lat\right\}}{\sqrt {\cos \!\left\{Azg\right\}^{2}+\sin \!\left\{Azg\right\}^{2}}}},$
	$={\frac {1}{\sqrt {\left[{\frac {\cos \!\left\{Azg\right\}\times \operatorname {M} \!\left\{Lat\right\}}{\operatorname {M} \!\left\{Lat\right\}\times \operatorname {O} \!\left\{Azg:Lat\right\}}}\right]^{2}+\left[{\frac {\sin \!\left\{Azg\right\}\times \operatorname {N} \!\left\{Lat\right\}}{\operatorname {N} \!\left\{Lat\right\}\times \operatorname {O} \!\left\{Azg:Lat\right\}}}\right]^{2}}}},$
	$={\frac {1}{\sqrt {\left[{\frac {\cos \!\left\{Aze\!\left\{Lat\right\}\right\}}{\operatorname {M} \!\left\{Lat\right\}}}\right]^{2}+\left[{\frac {\sin \!\left\{Aze\!\left\{Lat\right\}\right\}}{\operatorname {N} \!\left\{Lat\right\}}}\right]^{2}}}},$
	$=\operatorname {O_{e}} \!\left\{Aze\!\left\{Lat\right\}:Lat\right\};$

At a given point, an azimuth is an azimuth: Whether it is loxodromic or orthodromic only identifies the "behavior" of the line it represents--an azimuth of 73.263° means, at a given point, a direction of 73.263° from due north, PERIOD (end of discussion). Right?

Now consider the prescribed, accepted equation of the arcradius:

$Azg$ = Graticular (spherical), orthodromic azimuth at Lat;

$Aze$ = Elliptical, orthodromic azimuth at Lat;

\operatorname {P} \!\left\{Aze:Lat\right\}={\frac {1}{{\frac {\cos \!\left\{Aze\right\}^{2}}{\operatorname {M} \!\left\{Lat\right\}}}+{\frac {\sin \!\left\{Aze\right\}^{2}}{\operatorname {N} \!\left\{Lat\right\}}}}};

If one calculates a minuscule (ellipsoidal geodetic/orthodromic) distance and divides it by the spherical angular distance ("ADg", found via the "spherical cosines for sides" equation), it will nearly equal O_e{ $Aze:Lat$ }, not P{ $Aze:Lat$ }!
Consider this example (where $a=6378.136$ , $b=6356.75$ ):

Lat_{1}=33.682045083^{\circ };

Lat_{2}=33.682045085^{\circ };

\Delta Long=\ \ 0.000000003^{\circ };

ADg=\ \ 0.00000000986412851^{\circ },

=\ \ 0.00000000017216152034{\mbox{ rad}}\,\!;

Azg=78.30189780458^{\circ };

Aze=78.35474883236^{\circ };

Distance=\ \ 0.00000109899218359{\mbox{ km}}\,\!;

{\frac {Distance}{ADg}}=\mathbf {6383.49487983} {\mbox{ km}};

Now compare:

\operatorname {O_{e}} \!\left\{Aze:Lat\right\}=\mathbf {6383.49487983} {\mbox{ km}}=\operatorname {O} \!\left\{Azg:Lat\right\};

\operatorname {P} \!\left\{Aze:Lat\right\}=\mathbf {6383.49} {\mathit {759558}}{\mbox{ km}};

This should demonstrate that O_e{ $Aze:Lat$ } is the arcradius at ( $Aze,Lat$ ), not P{ $Aze:Lat$ }, shouldn't it? If O_e{Aze:Lat} is not THE arcradius, then what type of arcradius is it? And if P{ $Aze:Lat$ } is THE arcradius, then how does it relate to a minuscule distance?

I can't believe this concept is unknown—maybe archaic/obscure and/or just forgotten (or, more likely, known/recognized by another name—?).
Given that "original research" is a Wikipedia no-no, I would like to know if this concept/equation is recogized—or, if indeed this is OR, worthy of a paper at PlanetMath or some such site! P=) ~Kaimbridge~ 23:46, 29 October 2005 (UTC)[reply]

Don't take this the wrong way, but: what exactly have you been huffing? Kid Apathy 23:43, 29 October 2005 (UTC)[reply]

To put it more politely, the supporting math is fine, but please start with an English description of what you are trying to prove, in layman's terms. StuRat 16:44, 30 October 2005 (UTC)[reply]

(comment and reply moved from my talk page—shouldn't the the discussion stay here?) ~Kaimbridge~ 20:36, 30 October 2005 (UTC)[reply]

Hmm...very interesting question...What is the context of the original problem? --HappyCamper 01:49, 30 October 2005 (UTC)[reply]

Well, the "arcradius" itself is the problem! P=)
I know about geodetic formulation and its "conformal" nature, requiring an "auxiliary sphere" (I have copies of Sodano's and Vincenty's classic papers--as well as others--but I prefer Saito's straight-forward Gaussian Quadrature, all of which are given in Richatd Rapp's Geometric Geodesy, Part II <Ohio State Univ.>). Since great-circle distance equals the (arc)radius times the angular distance, it follows that the (arc)radius equals the distance divided by the angular distance. So, on an ellipsoid, the smallest possible geodetic distance divided by its corresponding graticular/spherical angular distance equals the arcradius at that latitude, in the direction of the geodetic line. Try it on a meridian (which is a "simple" ellipse): Calculate a minuscule distance and divide it by ΔLat (which, in this case, equals the graticular angular distance)—it will nearly equal M{Lat}/O{0:Lat}.
Now, before you get ahead of the discussion and think "hey, wait a minute, I know what he is up to...he thinks he found a geodetic formula using just Lat/Long, not requiring an auxiliary sphere and all its complications...but he doesn't realize...". But, yes, I do realize this wouldn't find the traditionally defined, conformal geodetic distance, but it does find the graticular geodetic distance—what I call the "parageodetic" distance—which is the elliptical distance on a spherical globe: That is, calculate the angular distance between the two points on the spherical globe, then, staying constrained to the graticule (which, by its origin, is always spherical, thus "graticular"/spherical), find the average elliptical arcradius along that great-circle segment and multiply the two together (in the same way you would multiply the average value of M{Lat} <between $Lat_{1}$ and $Lat_{2}$ > by ΔLat to find the distance along a meridian <between $Lat_{1}$ and $Lat_{2}$ >). Think of the antipodal case: The geodetic distance will always be north-south, along a meridian, as that is "conformally" the shortest distance (i.e., if you theoretically pulled a string from a point on the equator, along the equator, to the other side, the string would "lift" until it is north-south, when it reaches its antipodal point), whereas the parageodetic distance would be the elliptical distance along any great circle (also known as a "transverse meridian") between and including a common, vertical meridian and the common, horizontal equator. There is a popular geodetic approximation ("Andoyer's Approximation") that is actually a parageodetic approximation!
But I realize that the "parageodetic"—as far as I know—would be considered waaaaay out into original research land, so I'm not attempting to go anywheres near there! P=)
The idea of O{Azg:Lat}/"omniversal"/"transverse neridional" arcradius (at least in some form), however, I don't think is OR (especially if it is presented right). I suspect that it may just be a mostly forgotten concept, given all of the advances in geodetic formulation for finding the "shortest" (i.e., conformal) geodesic. Either that, or P{Aze:Lat} is supposed be the "omniversal"/"transverse neridional" arcradius in some other reference form (e.g, "reduced", "parametric", etc.), with some way to convert it to the more apparent O_e{Aze:Lat}—thus the question to the RD.
As for all of the loxodromic intro, that is meant to be an attempt at presenting O{Azg:Lat}'s derivation. ~Kaimbridge~ 15:46, 30 October 2005 (UTC)[reply]

chemical structure of rubber (natural and synthetic)

I have been loking around for the chemical structure of Natural Rubber and Synthetic Rubber but seem to be having no luck. Any webistes or books that anyone knows of and has some information of the chemical structure of rubber would be of great use to me.

Thank you

Our synthetic rubber article has some info. - Mgm|^(talk) 11:12, 30 October 2005 (UTC)[reply]

Latitude CPx Probelms, BSOD and more

This is what happens.

1. Laptop boots up fine, Connects to internet via 56k/LAN modem 2. Laptop runs for a while, then all the sudden, it flickers to a BSOD(Blue screen of death. The blue screen that has Windows error messages.) Then the comptuer instantly shuts down, like a force down, then starts rebooting, and go to the screen, where it checks for fragmentation (Something close to that) If I leave the Laptop off for a while, then i can turn it back on, and it will work fine, then goes back to step 2.

Then soemone told me to clean out the heat sink, and fins of the fan. I did, and i put the whole computer back togeather, and plug it in. I turn it on, and the Lights blink (CAPS Num, Scrool lock)they blink a couple times then it turns off. Nothing on the screen, nada. Did i just screw up my hard drive or something? Any Ideas on what's wrong?

I used to have a similar BSoD problem on my laptop where it would show the BSoD for about half a second and then force-down/reboot. This was nowhere near enough time to capture the error messages displayed. I thought of using a camcorder to record the screen, but the BSoDs were too sporadic for me to catch it. However, Windows did record the technical details to hard disk, and Windows told me it was a problem with a device driver. Further investigation led me to discover that this was my audio driver. My audio driver tends to have problems in other places, too.

So my guess is that there might be a link between your modem driver and the BSoD. And about your second (more serious) problem, well, it's a bit late to tell you this unfortunately, but in general you shouldn't take apart laptops. Even the professionals can make critical mistakes doing it. Everything is very compact and fragile, and it can be almost impossible to put back together a laptop successfully after taking it apart. Desktops are much, much easier because everything is neatly placed and substantially spaced out to fiddle with. It doesn't look like your laptop is even getting to BIOS; the Num, Caps and Scroll Lock lights flash as a basic circuit thing, but it doesn't seem to be progressing. Try pressing/holding F12 while turning it on, this usually activates the BIOS menu on most systems while it's going through. It's worth a try, however, I doubt it would work, and I'm sorry to tell you the news but the future for your laptop doesn't look good. -- Daverocks 13:04, 30 October 2005 (UTC)[reply]

Well it may be too late for my poor laptop, but this was a Goverment laptop, and i put XP on it, so how come 1-2 months after i start using, it, it starts having these problems? 69.181.206.232 17:48, 30 October 2005 (UTC)[reply]

Seems to be fixed. Had soem error with RAM think it overheated. But either way seems to be fixed.Lordned 19:32, 30 October 2005 (UTC)[reply]

October 30

LCD monitor problems

Hello, all. Before I purchased my new laptop, my old laptop was giving me quite a lot of problems. What happened is that sometimes, the LCD display would show some sort of "snow", but differently. If you had, for example, three white pixels aligned horizontally, a magenta pixel would appear next to the third pixel. Also, if there was a black pixel below and left of another pixel, that pixel would appear lime green (my guess is hexadecimal #00FF00). I don't use it anymore, but I've always wondered what was causing the problem. All the connections were properly plugged (I checked them myself several times), and I've heard somewhere that it could have been because of a property of LCDs, but I didn't get more explanations. Is that possible? If it is, what was causing it? Titoxd^(?!?) 03:47, 30 October 2005 (UTC)[reply]

Maybe a stuck pixel? Take a look, but it doesn't seem to explain why the pixel is faulty. -- Daverocks 12:09, 30 October 2005 (UTC)[reply]

Also, most LCD monitors warn of occasional random pixels, due to limits of the technology. That said, it sounds like your case may go beyond the normal range. StuRat 16:37, 30 October 2005 (UTC)[reply]

No, neither one seems to fit this problem. If you switched a window, producing a different combination of pixels, some of the magenta pixels would appear normal, and some of the normal would appear green or viceversa. It probably is one of those cases not covered by the six sigmas. Titoxd^(?!?) 01:06, 31 October 2005 (UTC)[reply]

Bridge type identification

I tried this on Talk:Bridge but didn't get a response. Can someone tell me - what sort of bridge is the Tasman Bridge? Concrete arch? More pics here. -- Chuq 04:42, 30 October 2005 (UTC)[reply]

I'm not sure about the construction technique, but by the look of it, I think it is a Box girder bridge. smurrayinaHauntedHouse...Boo!^{(User), (Talk)} 09:06, 30 October 2005 (UTC)[reply]

Prestressed concrete, including the columns. Not an arch. Do you need more info? --Commander Keane 14:55, 30 October 2005 (UTC)[reply]

Let's see...It is a beam bridge (as opsoded to an arch). It's not a box girder, it's I beams, specifically 14 precast, prestessed concrete ones (24 in. wide at the top of each).--Commander Keane 16:21, 30 October 2005 (UTC)[reply]

Coloured glass

Inspired by the biology question above, why is it that when I look at a tainted window on the outside it has the same colour as when I look at it from indoors? If the colour on the outside is a reflection of that wavelength, then on the inside I'd have to see white light without that wavelength, so the complementary colour. On second thoughts, I'd have to do this test with the lights out on the inside. Would that be the cause of it, that I see the reflection of the lights inside? But they're much weaker than sunlight, so that sounds unlikely. DirkvdM 07:21, 30 October 2005 (UTC)[reply]

Practically, you don't "see" the color of the glass, you see the color of the objects behind the glass. If I wear dark brown glasses, everything I see is tinted in dark brown color. I see dark brown dogs and dark brown cats.

Let's say the sunlight has R-G-B components (highly simplified) and your glass absorbs all green light:

Case 1: You're inside:

sunlight (RGB) → light hits an outside object (scattering; RGB) → glass → filtered light (RB) → your eyes (RB)

Case 2: You're looking from the outside to the inside (above):

sunlight (RGB) → glass → filtered light (RB) → light hits an inside object (scattering; RB) → glass (filtered again; RB) → your eyes (RB)

The complementary colour (G) is absorbed. You don't see it. You may see the direct reflct of the sun, but the color of the light reflected from the outer surface of the glass is not necessarily the color of the glass (affected by multiple factors). -- Toytoy 08:42, 30 October 2005 (UTC)[reply]

Ah, so it's a matter of absorption in stead of reflection. Makes sense. But where does the energy go? Is it turned into heat (sounds unlikely)? Or, another option I now think of, is the frequency changed? DirkvdM 08:14, 31 October 2005 (UTC)[reply]

Under the normal condition, most of the absorbed light energy turns into heat. If you place a blackened steel plate under the tropical sun at noon for a period of time, you can cook an egg on it. The heat in steel transfers to the egg very quickly. If you place a black plastic board under the sun, it will not cook the egg. Moreover, the object can always transfer the heat elsewhere. So the temperature will not rise indefinitely.

However, if you're in a typical living room, the artificial lighting is too weak to heat anything. (Fluorescent lamps: Too little infrared. Incandescent bulbs: Can only heatup nearby things.) If you're in a movie studio, these kilowatt lights can easily burn something if you fail to take reasonable care.

Frequency change is very unlikely if you're not talking about nonlinear optics. -- Toytoy 12:58, 31 October 2005 (UTC)[reply]

It should be noted that there are varieties of glass that reflect different colours differently. I have no idea what goes into them, but a local glassware company called Iittala makes various glass objects in a color they call "rose-olive", which looks greenish in reflected light but purple when seen against the light. A reasonably good image can be found at [29] (front left), but the effect is much more striking when seen in reality. In many photos on the web, such as [30], the glass simply looks lime green due to excessive reflected studio lighting. —Ilmari Karonen 16:00, 31 October 2005 (UTC)[reply]

These probably work by selectively reflecting (rather than absorbing) certain colours. If you look at light reflected off the glass, it look one colour, say green. If you look at light through the glass, it looks like the complimentary colour (magenta). Dichroic filters work the same way. You generally make this sort of effect by putting some kind of optical coating on the glass. --Bob Mellish 16:31, 31 October 2005 (UTC)[reply]

Statistic on death worldwide, due to Malaria, from an admissible source (WHO preferred)

I am looking for a single figure on deaths worldwide due to Malaria (I believe the figure is about 1 million) from an admissible source, such as the WHO. I've looked on their site, but cannot find a stated figure for 2004 or estimated for 2005. Many thanks! --08:58, 30 October 2005 (UTC)

The first paragraph of the WHO malaria site says "more than one million people...a year." Hope that helps. - Akamad 19:50, 30 October 2005 (UTC)[reply]

Thank you! A more specific figure would be cool, but that'll do in the absence of one! Thanks again --19:57, 30 October 2005 (UTC)

Yeah I imagine getting accurate numbers would be difficult, this WHO document (PDF) puts the number of deaths betwen 0.7 and 3 million (page 13). Akamad 02:57, 31 October 2005 (UTC)[reply]

Enthalpy

What is the ΔH_c of Methanol and Hexane? smurrayinaHauntedHouse...Boo!^{(User), (Talk)} 10:24, 30 October 2005 (UTC) [reply]

For methanol, by calculation, I get −726.8 kJ/mol. I don't have Δ_fH for hexane handy at the moment so I can't do the calculation there. You can find measured values at the Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD) . Physchim62 (talk·RfA) 16:47, 30 October 2005 (UTC)[reply]

Water on Earth

Has all of the freshwater on earth already been drunk before by animals and humans? That is, is all drinking water purified urine? Jazz1979 10:45, 30 October 2005 (UTC)[reply]

Nearly certainly, considering that land animals have been around for the past several hundred million (a billion even? Don't listen to me, I'm not a geologist nor a biologist) years. Look at it this way - something that's passed through so many kidneys has to be clean, right? -Sam Pointon 12:19, 30 October 2005 (UTC)[reply]

I think the general idea is that life has been on Earth for over 3 billion years -- although most of that time life was just simple organisims like bacteria. Given that idea, I would say that almost all of the water on the surface of the planet has been used by some organisim or another, although probably not by humans (a realitvley young species).

But it's not just your drinking water here, you breath in water vapor with every breath, so you're drinking that ex-urine too. ;-) --Quasipalm 16:15, 30 October 2005 (UTC)[reply]

"You are made of star dust !" - Carl Sagan

"You are made of dinosaur poop !" - Me - StuRat 16:29, 30 October 2005 (UTC)[reply]

If there's some water somewhere on Earth that has escaped contact with life (a real eternal permafrost?) then it's quite unlikely that you will get in contact with it. By the way, the purification is most likely done by evaporation; cloud creation over seas > rain over land > your drinking water. But does this mean that all the seas are concentrated piss? DirkvdM 08:22, 31 October 2005 (UTC)[reply]

Carbon redux

For context, see #Carbon, above.

Okay, I'm curious... how is carbon used in dentistry? ‣ᓛᖁ♀ᑐ 13:00, 30 October 2005 (UTC)[reply]

I believe dental drill bits are often diamond dust coated. (Note that the article on dental drills didn't exist when I wrote that list, so I decided to just link to dentistry and let the reader puzzle it out. I've since started the article; corrections and improvements are welcome.)

The list actually happens to be quite comprehensive, as it includes three different carbon allotropes plus organic compounds. Probably not what the teacher expected, though. —Ilmari Karonen 13:29, 30 October 2005 (UTC)[reply]

I don't have a clue how elemental carbon would be used in dentistry, at least the way it is practiced in the United States. This is a stretch, but some water purification systems in dental equipment may contain activated charcoal filters.

Of course, carbon is part and parcel of all organic life, which pertains to dentistry, as it does to all the health professions. Dental burs ("drill bits") may be composed of carbon steel, and are tipped with tungsten carbide. But elemental carbon? I don't think so... --
Mark Bornfeld DDS
dentaltwins.com
Brooklyn, NY 21:37, 30 October 2005 (UTC)

Laptops and note books

Why don't laptops and notebooks have VGA screens?

What do you understand by "VGA"? Viewed as a standard size in pixels, most laptop computers have a better-than-VGA screen, just like most desktop computers. Notinasnaid 13:44, 30 October 2005 (UTC)[reply]

If you're asking why they have LCD rather than CRT screens, it is because of the size difference between the two. --Fastfission 14:38, 30 October 2005 (UTC)[reply]

I get a 1600x1200 resolution on my laptop, which is well beyond VGA. StuRat 16:26, 30 October 2005 (UTC)[reply]

Spanning tree

Not really sure where to put this but the following anon 84.59.113.235 has created three articles on spanning trees that look like complete gibberish. Can someone expand them into encylopedic stubs? Theresa Knott (a tenth stroke) 17:04, 30 October 2005 (UTC)[reply]

How about a link so we can find it ? -> spanning tree. StuRat 20:47, 30 October 2005 (UTC)[reply]

Do you mean the mathematics or the network protocol article or both ? StuRat 20:51, 30 October 2005 (UTC)[reply]

She meant the articles in Category:Spanning tree. --R.Koot 21:13, 30 October 2005 (UTC)[reply]

I see what you mean, those 3 articles do need work. StuRat 21:55, 30 October 2005 (UTC)[reply]

I'll see if I can expand them a little after my exam week. --R.Koot 23:23, 30 October 2005 (UTC)[reply]

Methane

Hello, this is related to another question I saw on another page. My question is I know that the chemical methane is added to the nicotine leaves to aid in burning. Would the leaves be able to burn or burn well without this chemical and how is it that the smoke doesn't blow up since it is a dangerous chemical when someone lights up? Also, what other chemicals besides methane are added to the niotine leaves not the paper to make it burn and burn slowly?

It has to do with the concentration of methane. Too low of a concentration just provides a nice even burn. At a higher concentration you can get an explosion. At the highest concentrations you no longer get explosions due to a lack of available oxygen, interestingly enough. StuRat 20:42, 30 October 2005 (UTC)[reply]

Potassium nitrate is added to cigarette tobacco in many countries to make it burn faster and to make it harder to extinguish. There used to be special cigarettes for sea fishermen which had a particulerly high potassium nitrate content and which were virtually unextinguishable even in a gale! Physchim62 (talk·RfA) 10:15, 31 October 2005 (UTC)[reply]

Lungs

What is the anatomical position of the lungs?

In the chest in most of us. If you are writing a xenobiology report for your home planet, you can say that humanoids have lungs within the thorax that take up most of the space within. They are cephalad from the diagphragm and caudad from the neck. They surround the mediastinum. And please emphasize in your report that humanoids taste really bad. alteripse 18:53, 30 October 2005 (UTC)[reply]

That somebody doesn't know where their lungs are just takes my breath away. StuRat 20:36, 30 October 2005 (UTC)[reply]

<sigh> lame jokes make me gasp Theresa Knott (a tenth stroke) 22:25, 30 October 2005 (UTC)[reply]

If you don't think that's shocking, according to the November, 2005 American issue of Playboy, "20% of Americans think the sun orbits the earth. 17% know the earth orbits the sun but think it does so every 24 hours, not every 365 days." No, I don't know where they got their data. Dismas|^(talk) 22:37, 30 October 2005 (UTC)[reply]

95% of those who answered everything correctly didn't notice that they are visitors from Europe, Africa, Asia, Oceania or South America. :) Playboy rules! Now give me a playmate. -- Toytoy 06:35, 31 October 2005 (UTC)[reply]

I think they got them from the NSF's Science and Technology Indicators surveys. Note the charts to the left; sadly, Europeans don't do significantly better or worse than Americans---more Europeans think lasers work by focusing sound waves, whereas more Americans think that the earliest humans lived at the same time as the dinosaurs. grendel|khan 18:01, 31 October 2005 (UTC)[reply]

Bad survey technique. Those guys were distracted by the pictures. alteripse 00:36, 31 October 2005 (UTC)[reply]

With out stupid people there would be no smart people--Eye 22:53, 31 October 2005 (UTC)[reply]

Integration of Second Derivative

I have that ma=-(k squared)/(x to the third). And you have that a is the second derivative of x with respect to time. I need to fine x of t, x(t). How do I do the integral of a second derivative to get x of t? Confused. Please help.

ma=-{k^{2} \over x^{3}}

This is a differential equation, since

a=d^{2}x/dt^{2}

.

~~Try repeated Separation of variables and integration.~~

~~Separated, this is:~~

— Sverdrup 18:47, 30 October 2005 (UTC)[reply]

Actually, I don't think you can apply that trick, at least not easily, for second derivatives. I'll explain momentarily. -- SCZenz 22:42, 30 October 2005 (UTC)[reply]

Well, I got distracted, but I'll explain now. First of all,

d^{2}x\neq (dx)^{2}

, but anyway let's try to apply the trick twice and see what happens. We have, with f(x) = -k²/(mx³),

{\frac {d^{2}x}{dt^{2}}}=f(x)

Thus

{\frac {d}{dt}}({\frac {dx}{dt}})=f(x)

Which gives

{\frac {1}{f(x)}}d{\dot {x}}=dt

You might hope that your variables are now separated, but in fact

{\dot {x}}

= dx/dt is a function of both x and t so they aren't. I don't know of a way to apply the trick to second derivatives. Maybe someone who knows more math than me can comment further. -- SCZenz 07:52, 31 October 2005 (UTC)[reply]

Long time since I did this, so almost certainly wrong:

{\frac {d^{2}x}{dt^{2}}}={\frac {dv}{dt}}=({\frac {dx}{dt}})({\frac {dv}{dx}})

By basic chain rule. So you then have 1/2 m v^2 on one side and the integral with respect to x on the other. Physically, think of it as calculating the kinetic energy gained/lost as you move a distance under a given force. You can then get x(t) by direct integration, if you do some clever square rooting and rearranging.--Fangz

Interesting. Should've thought about it longer, it felt quite wrong actually. I recognize what Fangz does though, that must be how I solved this kind of problem in my mechanics classes. Hmm. I really need to study this a bit more. Sorry for the bad advice. — Sverdrup 19:15, 31 October 2005 (UTC)[reply]

global warming

why is the % of carbon dioxide in the atmosphere so small?

Take a look at the article Earth's atmosphere. The atmosphere was primarily composed of carbon dioxide and water vapour. As the planet cooled, the water vapour condensed into oceans and seas, and the water in turn dissolved most of the carbon dioxide. The evolution of photosynthesizing plants resulted in further reduction in CO₂ levels. -- Canley 22:31, 30 October 2005 (UTC)[reply]

Long ago the evil chloroplast-bearing plants took over the earth and consumed all the CO2, emitting all this corrosive oxygen. If we all breathe hard enough, maybe we can reverse this state of affairs, lower the O2 level, and raise the CO2 level again. alteripse 03:28, 31 October 2005 (UTC)[reply]

No worries, we've already invented cars to do that for us. Aren't we clever? DirkvdM 08:35, 31 October 2005 (UTC)[reply]

In addition, in case you are wondering, the significance of this with regards to the current global warming situation is that we don't need to worry about destroying the world, or indeed all of life, only ourselves and our current civilisations.

Indeed. Destroying the Earth is harder than you may have been led to believe. grendel|khan 18:08, 31 October 2005 (UTC)[reply]

Hospital

What is a hospital district?

It's the district covered or serviced by a hospital. So if were sick or injured in the Union County Hospital District in Illinois, you would be taken to the Union County Hospital. -- Canley 05:02, 31 October 2005 (UTC)[reply]

October 31

Solution

How do I find the mass of a solution given the mass of the solute?

You need the concentration of the solution. Perhaps molarity or molality, depending on what the homework problem is asking. Titoxd^(?!?) 02:19, 31 October 2005 (UTC)[reply]

You also need to understand the principle of conservation of mass. Note that volume is not conserved. Physchim62 (talk·RfA) 10:18, 31 October 2005 (UTC)[reply]

I don't think it is entirely certain that mass is conserved when something is dissolved. In most cases, probably, indeed I expect that's what our questioner requires, but what if you are trying to dissolve calcium carbonate in a weakly acidic solution?--137.205.18.131 13:57, 31 October 2005 (UTC)[reply]

Remember that mass is conserved in a closed system - in this case you need to take into account the liberation of the carbon dioxide. If you don't, well, obviously mass isn't conserved. --216.191.200.1 14:18, 31 October 2005 (UTC)[reply]

UTS of indented prestressing steel wire

As per different standards of indented prestressting steel wires, it is seen that as the diameter of wire increases Ultimate Tensile Strength (UTS) decreases. As an example minimum UTS of 4mm dia wire is 1715 N/sqmm while that of 5mm dia wire is 1570 N/sqmm.

When enquired from different manufacturing agencies, it is learnt that while drawing from same parent material, by cold drawn process, Breaking load decreases which is not in the same propotion as that of diameter. Since UTS = Breaking Load/Area, it varies.

Why the Breaking Load of these steel wires does not decrease in same propotion as that of diameter of the steel wire? Is there any molecular changes involved in it, if so what is that?

MALOY NANDI

It's not directly related to the diameter. Nor is there any kind of molecular change cause by an increase or decrease in diameter. See Strength of materials, and also check out Solid Mechanics on the Wikibooks site. Proto t c 09:53, 31 October 2005 (UTC)[reply]

Then why does UTS decreases with increase in diameter of Plain Drawn Steel Wire?

MALOY NANDI

It's to do with its Young's modulus, and the relationship of stress and strain. The relationship is different for every material. Read the article on the Wikibooks site. Proto t c 12:30, 31 October 2005 (UTC)[reply]

From the Australian Standards, the brekaing load for 7mm and 5mm wire is proportional to diameter squared. Also, the 7mm wire has a higher UTS than the 5mm wire. Are you sure you are just talking about wire and not strands and bars? I'd like to discuss this further.--Commander Keane 18:05, 31 October 2005 (UTC)[reply]

Electron mass

I understand the electron mass is the best measured particle mass, to an accuracy of some 10 digits. I am wondering if there have been any attempts to test whether the mass is in fact a constant, or if it is changing over time (if the mass changed significantly over cosmological times, there could conceivably be a change in the 10th digit over a few decades or so). And, which property is actually measured in this precise number of e mass: is it the relation to the proton mass? Which definition of the kg is intended when they say m=0.510998918(44) MeV/c**2 ? Would a change in elementary particle mass that leaves the ratio of e to p masses intact even be registered, or would that be equivalent to a change in the gravitational constant? Baad 08:12, 31 October 2005 (UTC)[reply]

The accuracy of the measurement, according to the particle data group, has improved by a factor of 5 since 1999 and by a factor of 50 since 1987 [31]. Thus if there were changes in those last few digits over decades we wouldn't have seen them. All the measurements listed since 1987 are easily consistent within 2 sigma (i.e., close enough that they don't indicate any inconsistency), and presumably before that even fewer digits of precision are available.

The most accurate measurements are made relative to the mass of a carbon-12, which is defined to have a mass of 12 atomic mass units. The measurements in electron volts are less accurate, because the conversion involves the elementary charge, which is not as accurately known as the masses themselves. Proton mass measurements are independant and have the same limitation [32]. They're not measuring the electron mass over the proton mass at all.

As for your question about whether a change that kept the ratio intact could be registered, that would depend on what else changed—assuming all particle masses scaled in the same way but other laws of physics left intact, the changes would still register because some of the mass in carbon-12 is determined by the nuclear binding energy (and thus by the nuclear force), so its mass wouldn't scale in quite the same way as the proton or electron. (In fact, if you only changed the masses of elementary particles, the proton mass wouldn't change much at all, because almost all of its mass comes from the strong force and not from the masses of its constituent quarks.) Let me know if you have more questions. -- SCZenz 08:37, 31 October 2005 (UTC)[reply]

interesting... but, on second thoughts, I assume changing e or p masses are not an issue anyway, since they would register in the H/He emission lines of ancient galaxies? Or are these independent of particle mass? Baad 09:05, 31 October 2005 (UTC)[reply]

They depend strongly on the electron mass, but only a little on the proton mass. -- SCZenz 09:09, 31 October 2005 (UTC)[reply]

ah, but on third thoughts, since the known 'contemporary' frequencies are presupposed to estimate the Hubble constant, that's not true; if the masses changed, we'd be wrong about the age of the Universe, but we couldn't tell. Baad 09:14, 31 October 2005 (UTC)[reply]

There's more than one source for the age of the universe; having something odd like that screw up our ideas without us realizing it would be very difficult to set up in a self-consistent way. -- SCZenz 09:19, 31 October 2005 (UTC)[reply]

well, the age of the Universe is certanily not known to ten digits' accuracy :) so if the mass of the electron changed, say, 10% over the last ten billion years, I doubt that we would be able to detect it. Baad 09:53, 31 October 2005 (UTC)[reply]

The problem is that electron mass is tied up with a number of other things - according to certain theories, it is a result of deeper principles. (maybe. I'm fairly uncertain here) Even the possibility of electron mass changing would mess up a great number of things. --Fangz 20:52, 31 October 2005 (UTC)[reply]

Enzymes

Why are enzymes inactivated at low temperatures???

See enzymes. Proto t c 09:41, 31 October 2005 (UTC)[reply]

Enzyme activity depends of kinetic energy and the movement of molecules. At low temperature there is less movement and less enzyme activity. If you totally prevent molecular movement you can stop enzyme activity. Sadly, neither the enzyme article nor even the Enzyme Kinetics article describes the effect of temperature on enzymes activity. There is a tiny bit at Rate of enzyme mediated reactions. Here is some more information (about half way down the page). A few more details. --JWSchmidt 14:22, 31 October 2005 (UTC)[reply]

Flu jab

Why can't you take the flu jab when you are sick?

Because it gives you a very mild case of the flu, and if you're already sick, it can be exacerbated into a more serious case as your body's defenses are weakened. Proto t c 09:43, 31 October 2005 (UTC)[reply]

Not quite. For most people, it doesn't make you sick. The two reasons are (1) liability and safety, and (2) the theoretical concern that effectiveness may be reduced. If a person is sick, he can be sick in many ways and there are many different outcomes (from full recovery, to complicated illness, to death). Although it is extremely unlikely that this type of intervention would change the course of a current illness, the doctor caring for the patient and the person or organization or corporation providing or making the flu shots do not want another variable added in to the illness and especially do not want the flu shot blamed for the outcome of the illness. A lesser reason is that during the acute phase of another viral infection, the immune response to a flu shot might be altered in such that the long term protection response may be lessened. This is mainly a theoretical concern and has not been proven or even well-studied. alteripse 12:17, 31 October 2005 (UTC)[reply]

I assume that "flu jab" is a British term meaning influenza vaccination. Some anti-viral vaccines contain active viruses - almost always a virus strain that does not cause illness. Other anti-viral vaccines contain inactivated virus or purified viral proteins. The purpose of flu vaccination is to expose the body to flu virus proteins that will stimulate the immune system to protect the body against future infection by flu virus. Generally, you want to be vaccinated several weeks before being exposed to a flu virus that could make you get sick. Once you have the flu, your body is already being exposed to the proteins of the flu virus and your immune system is responding to defend you. Adding a flu vaccine to your body would not be of any significant additional advantage. The flu virus that is making you sick is itself acting like a very efficient vaccine in the way it stimulates your immune system. The problem is that it takes about a week for your immune system to respond enough to win its battle against the virus infection. If you were vaccinated before being infected by a flu virus, then the immune system of your body will contain things like memory B cells that will make it easier for your body to react quickly to defend against the infection. --JWSchmidt 13:58, 31 October 2005 (UTC)[reply]

Chlorophyll

Why is chlorophyll green in colour??? I mean why it has to be green to be able to absorb light?

(From the article) Chlorophyll absorbs mostly in the blue and to a lesser extent red portions of the electromagnetic spectrum, thus its intense green color. This applies to plant chlorophyll. Chlorophyll does not always have to be green - there are also purple bacteria, which use bacteriochlorophyll, which absorbs infrared light. Proto t c 09:48, 31 October 2005 (UTC)[reply]

The long answer is that (a) it absorbs more or less the right band of energy - the green colour is light that is not absorbed, and well, green light isn't very common on earth, (b) it coincidentally works chemically with photosynthesis, (c) it just happens to hold the right balance between cost of synthesis and and efficiency for most plant life, and (d) it happened to be picked early on by evolution, and there is no real selective pressure to change it. At least, that's my not-very-rigorous opinion. --Fangz

Light in the green wavelength is exactly as common as light in any other visible wavelength. Tempshill 22:15, 31 October 2005 (UTC)[reply]

1) "it just happens to hold the right balance between cost of synthesis and and efficiency for most plant life" This does not sense as far as i can tell. If the cost is the synthesis of chlorophyll, and it can absorb many photons, why is the efficiency relevant?

2) it happened to be picked early on by evolution, and there is no real selective pressure to change it. This does not seem right either. There are accessory pigments in plants that are not green. Carotenoids and xanthophyls are red and yellows, hence the autumn colours. It seems evolution has and does use other variations if needed. Also chorophyll a and b have different, non overlapping absorbtion spectrums suggesting that the absorbtions characteristics are not fixed and someone has already mentioned the bacterio chlorophylls that are purple and absorb mostly in the infra red ONLY. David D. (Talk) 22:46, 31 October 2005 (UTC)[reply]

Water

Does water/moist conditions promote hair growth?

No. Unless it contains a lot of testosterone, and you drink it. Proto t c 09:44, 31 October 2005 (UTC)[reply]

hair

What is the purpose of pubic hair growing around the reproductive organ of both man and woman?

See puberty and pubic hair. Proto t c 09:44, 31 October 2005 (UTC)[reply]

I would say two purposes:

Lubrication. Places where rubbing occurs could lead to abrasions. Hairs reduce the friction. To test this, rub two hands together, then put some hair between them and rub again. It should be easier afterwards. Armpit hair serves the same purpose.

Age marker. Body hair is a way to mark that a person is of reproductive age, which is an important thing for any species to be able to distinguish. This explains why young children don't have body hair. Of course, there are many other age markers as well.

StuRat 16:59, 31 October 2005 (UTC)[reply]

I would have to disagree with the lubrication remark. There are fluids both the male and female body release to accomplish lubrication. We might call it pre-ejaculatory fluid. ~~Therefore StuRat, I believe your friction argument has no bearing here.~~ As for it being an age marker: that's just more of an unrelated side-effect. In my opinion it has more to do with heat loss. One reason why the hair on our heads has remained throughout evolution has to do with the fact that we lose a large amount of heat out of the top our heads. This is one reason why beanies are so effective. I think this point carries over to our genitals as well. Also, major arteries run through the armpits out into the arm, so I believe my heat loss argument also applies to armpit hair. Remember, at one point in time our ancestors were completely covered in hair, even at birth. Once we started wearing animal furs/clothes to endure the ice-age and the cold northern winters, over millions of years body hair became more of a nuisance rather than a nessecity. It is possible that in another million years or so our bodies will be completely devoid of hair. So long story short: it is simply a way to minimize heat loss. - Cobra Ky

(talk, contribs) 19:41, 31 October 2005 (UTC)[reply]

I don't believe in the heat loss explanation - if that was true, then an external scrotum and pubic hair would work at cross purposes. Everything2 has an explanation - which you may or may not decide to trust. http://everything2.com/index.pl?node=pubic%20hair --Fangz 20:48, 31 October 2005 (UTC)[reply]

Well, reading more into it, there are several resources that confirm the friction argument. But there are also just as many resources that confirm the heat loss argument. Here is just one. Which surprises me that there is no mention of it in our wikipedia article on pubic hair. But there is mention of heat loss in our hair article. My opinion still stands, but I do retract my statements about the friction argument having no bearing. - Cobra Ky

(talk, contribs) 20:58, 31 October 2005 (UTC)[reply]

This is hearsay, but I recall an American Red Cross pamphlet on survival swimming that claimed the places on the human body where most heat loss occurs are the head, armpits, and groin. Human hair in those locations might be particular to the insulation property of hair. Tempshill 22:13, 31 October 2005 (UTC)[reply]

Does trebble cause more hearing loss than bass?

Which causes more hearing loss, high-pitched or low-pitched sounds? Or, does it not matter? I recently bought earphones that have much more pronounced trebble, but the other night I had ringing ears after using them for an extended period. It made me wonder... --Quasipalm 14:11, 31 October 2005 (UTC)[reply]

It depends on how you measure it:

An equivalent decibel loudness will cause equivalent damage.

An equivalent energy will cause more damage in the treble range, since treble sounds require less energy per decibel to produce. This means the same energy range will provide a louder sound in the treble range.

You may be encountering the second problem. I suggest you use the equalizer to turn the treble down/bass up to counter this tendency. StuRat 15:43, 31 October 2005 (UTC)[reply]

axiom of regularity

The axiom of regularity

Axiom of regularity (or axiom of foundation): Every non-empty set x contains some element y such that x and y are disjoint sets.

Disjoint: Maths (of two sets) having no members in common (Collins Dictionary)

This makes no sense to me. How can x and y have no common elements if x contains y. Surely y is a common element.

Danny Ryan

See our article at Axiom of regularity. It really means alot less than you think it does. As a set, x and y share no elements. (If you choose the right y) I.e. y doesn't contain some element that is already contained in x. Which, in a simple set, is fairly obvious if y isn't itself a set.--Fang

Consider the set x={ {1,2} , 3}. x contains two elements, 3 and {1,2}. Both of them are disjoint with y, since they contain no common elements. {1,2} contains 1 and 2, while x does not. 3 is a number and so doesn't contain any elements. According to regularity, all sets work like this. For an example of a (hyper-)set that does not satisfy regularity, consider z={{{{....}}}}. Note that z={z}, so the set and its element are not disjoint. Regularity ensures that sets don't have infinite nests of subsets. -Lethe | Talk 15:25, 31 October 2005 (UTC)[reply]

physics

how do i get contacted with physics sicentist so that i can solve my queries regarding physics problems. i am pursuing my phd in this field and i want answers that i am facing it difficult to be answered. — Preceding unsigned comment added by 202.92.68.98 (talk • contribs) 08:36, 31 October 2005 (UTC)[reply]

are you serious? You are pursuing a phd in physics, and you are not in contact with any physicists? that sounds pretty hopeless to me. 83.77.216.101 15:40, 31 October 2005 (UTC)[reply]

If you are serious and not an advocate of an original theory (the world abounds with people claiming to have proven Einstein wrong, etc.), you may be more likely to receive a response if you establish a username and say more about yourself. -Walter Siegmund 16:15, 31 October 2005 (UTC)[reply]

Why don't you post a query now? Dominick ^(ŤαĿĶ) 16:05, 31 October 2005 (UTC)[reply]

If you really are pursuing a PhD in physics, try a faculty advisor. You can also try posting the questions here. StuRat 16:40, 31 October 2005 (UTC)[reply]

Charles Darwin and Edward Blyth?

Doing some reading on talkorigins.org led me to trueorigins.org and a few of their articles. There seems to be a creationist idea that Darwin nicked the idea of natural selection from Edward Blyth, who was a creationist. I ask because the Wikipedia article on Blyth (see above) mentions this. How legit is this? I hesitate to believe a darn word the creationists say, which is why I bring this up. grendel|khan 18:13, 31 October 2005 (UTC)[reply]

Darwin was certainly influenced by creationists like Blyth (here is a website that claims Blyth as a creationist). However, the challenge would be to point to a published article that existed before those of Darwin and Wallace that coherently expressed the idea of a fundamental role for natural selection in the origin of new species. Blyth wrote things like, "The original form of a species is unquestionably better adapted to its natural habits than any modification of that form." (see) Darwin was able to escape from this kind of thinking about species as fixed forms. --JWSchmidt 18:53, 31 October 2005 (UTC)[reply]

BIODIESAL FUEL MANUFACTURING

I have a high interest in both the environmental and financial benefits of converting used cooking oils into biodeisal. Problem is that I have no idea of where to begin in researching relative equipment, necessary chemicals for the procedure, and overall cost of initial set up. Also to consider is the different environmental laws to be met dependant upon the different states. Help!!! --**--

I believe an experiment was done where two people drove cross-country using a conventional engine with only minor modifications and using cooking oil from restaurants as fuel. The only processing they performed was to filter the cooking oil. StuRat 20:13, 31 October 2005 (UTC)[reply]

The articles on biodiesel give a good starting point, and, depending where you live, there are probably associations not too far from you that do this. Where do you live? Trollderella 22:44, 31 October 2005 (UTC)[reply]

The Australian rat, the most sexually active animal

Im doing a research on the most sexually active animals on the face of the earth. It has come to my attention that a certain wild rat in Australia is the MOST sexually active as during the mating season, the male rat goes on a mating rampage where it does not stop to eat or drink but goes on mating for weeks until it dies of hunger and dehydration. may i know the nam of this particular rat? thank you very much.

Mel Gibson ? StuRat 22:56, 31 October 2005 (UTC)[reply]

@@ Line 2,886: / Line 2,886: @@
 == The Australian rat, the most sexually active animal ==
-Im doing a research on the most sexually active animals on the face of the earth. It has come to my attention that a certain wild rat in Australia is the MOST sexually active as during the mating season, the male rat goes on a mating rampage where it does not stop to eat or drink but goes on mating for weeks until it dies of hunger and dehydration. may i know the nam of this particular rat? thank you very much..
+Im doing a research on the most sexually active animals on the face of the earth. It has come to my attention that a certain wild rat in Australia is the MOST sexually active as during the mating season, the male rat goes on a mating rampage where it does not stop to eat or drink but goes on mating for weeks until it dies of hunger and dehydration. may i know the nam of this particular rat? thank you very much.
+:Mel Gibson ? [[User:StuRat|StuRat]] 22:56, 31 October 2005 (UTC)

Revision as of 22:56, 31 October 2005

October 18

Facial Hair Growth

LEVERS

Barometer

alligators and crocodiles

How to seperate chlorophyll a & b,and carotenoids before doing the Absorption Spectrum of Chlorophyll a

Drugs and Alcohol

enviroment and its relation with geography

QF 25 pounder Short Mark 1 (australia)

Sales of commonplace automobiles

What is the 'Vero cell line'?

Elementary particles

Laptop and digital camera woes

Some Ballistics

Domain name transfer

October 19

Ink Markers

Polynomial bound attainment

Spaces in fixed-width fonts in Microsoft Office Word 2003

Life on other planets.

Brain hyperactivity

Define gravitation

Basic binary sum circuit

astrophysics

Sand bags

A few questions about Hybrid vehicles like Prius

Avian influenza

Pulseless Electrical Activity PEA (EMD)

Infinity

October 20

Computer science and math skills

Excel column headings

Who manufactures the buses of the so-called "Wiki Wiki" shuttle line at Honolulu International Airport?

What are the interrelationships between science and technology?

CCE

Opening Matlab

Breakdown of a trillion dollars in ways people can easily understand.

"Unit" means "Mols"?

Computer upgrade

Liquid Leaking out of my hard disk

How much virtual space exists in persistent worlds?

Gynecologist Paradox

Yahoo dormant email accounts

Consumption of electricity of speaker and fan

Buckminsterfullerene/Buckyball

why is the Earth a sphere

Sudden Change

solubility of hydroxylapatite vs. pH

Red/turquoise contrast problem.

Carbon

Plants Of The Amazon Jungle

white film on magnesium strip, plz help ASAP

How to find experimental percent composition of magnesium and oxygen in Magnesium oxide?

October 21

Coulombs law

Internet Protocol

rosenberg generator

Light in a box

how to prepare soft drinks?

lightning?

Crocodilians in Guatemala

All about health

Water

INDIA

concerning the ontological status of dimensions.

Partial vs total differentiation

October 22

What are the bond angles of buckyball?

Peak busy hour

PRODUCTION FUNTION CURVE (**** URGENT****)

space shuttle

AIDS

Equation editor on Word

Toothpaste Vs Charcoal

Do wild animals snore?

How do dogs recognize each other?

Windows XP log on screen

Help identifying frog photo

Frog, Part II

PRODUCTION FUNTION CURVE ( URGENT)