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October 30

Collar-size of the woolly mammoth

Ok, I want to put a 16th century ruff about the neck of a woolly mammoth. How large would it have to be? Here's the dimensions from the WP article: they were not noticably taller than present-day Asian elephants, though they were heavier. Fully grown mammoth bulls reached heights between 2.8 m (9.2 ft) and 4.0 m (13 ft); the dwarf varieties reached between 1.8 m (5.9 ft) and 2.3 m (7.5 ft). They could weigh up to 8 tonnes.

Thanks Adambrowne666 (talk) 00:57, 30 October 2009 (UTC)

Is there some wooly mammoth neck diameter-mass-height ratio algorithm you know exists, but just don't know what it might be? Maybe figure one out based on the present day Asian elephant and fudge it -- ruff oglers will never know! DRosenbach ^{(Talk | Contribs)} 01:49, 30 October 2009 (UTC)

If you have access to a woolly mammoth for the dressing in a ruff, why can't you just use that access to also go in ahead of time to take a measurement? Dismas|^(talk) 04:53, 30 October 2009 (UTC)

What? And spoil the surprise? Bielle (talk) 05:13, 30 October 2009 (UTC)

I was cheered up no end by thinking about woolly mammoths wearing ruffs! Readro (talk) 10:22, 30 October 2009 (UTC)

You will need Photoshop. Cuddlyable3 (talk) 17:37, 30 October 2009 (UTC)

The mammoth can be any size. The collar will have to be tailored to fit anyway.Cuddlyable3 (talk) 14:45, 31 October 2009 (UTC)

There are some museums which have life-size reconstructions of mammoths. Since there are real mammoths recovered in various states of decomposition from glaciers, these are likely to be fairly accurate, if recently constructed. I seem to recall a couple of such reconstructions outside the Cincinnati Museum of Natural History in early 1990, but the museum moved to new premises later that year, possibly discarding the mammoths, and these reconstructions are probably too old to be of use anyway.

Knee injury test

I was watching a documentary on football injuries. When testing for knee injuries, they did all the tests that I am used to seeing. Then, they did one that I don't understand. The person being tested took about one step forward with one foot. Keeping the back leg straight and bending the front leg, the person would apparently just shift his weight forward. Is this a standard test for a specific type of knee injury? If so, what is being tested? -- kainaw™ 03:19, 30 October 2009 (UTC)

Don't know specifically what the test is for, but that was a common exercise during physical therapy after my knee surgery. I know I did a lot of stuff related to the patella and making sure its accessory tendons and such were working to keep it properly centered, but I'm not sure if that specific exercise was related. — Lomn 12:29, 30 October 2009 (UTC)

It may very well be rehab and not a test. I don't know why I didn't think of that. Thanks. -- kainaw™ 12:41, 30 October 2009 (UTC)

I'm not aware of this as a specific test. However the manoeuvre causes tension on the quadriceps muscle and the quadriceps tendon (and to a lesser degree on the posterior cruciate ligament). It could be used as a test of quad muscle/tendon integrity. Axl ¤ [Talk] 19:47, 30 October 2009 (UTC)

This is ringing a very faint bell for me. Slap a "citation needed" tag on this, but ISTR that they're looking at whether the patella shifts (left-right) as the leg moves. I've been looking through this rather impressive list of knee tests, but don't see what you're describing or what I'm remembering. Could be a place to look through, though. Matt Deres (talk) 23:58, 31 October 2009 (UTC)

Jumping on concrete versus sand

When we jump on concrete we get more hurt then when we jump on sand!can we explain this by third law of motion? My sir told me 2answer according 2the seceond law of motion but i answered it according 2the third law saying that since the particles of sand r very fine compared to that of concrete they r not able 2offer enough resultant force as concrete does.....so we feel more hurt?

Is it correct? —Preceding unsigned comment added by 86.96.128.10 (talk) 10:06, 30 October 2009 (UTC)

Would it be the fineness of the sand particles, or the fact that they absorb more energy in the form of being displaced rather than posing a resilient barrier to the force and returning an equal an opposite force. It's like punching balloon (filled with air) or a punching bag. It's not that the air particles are smaller than whatever particle size composes the contents of a punching bag -- it's that the air moves away much more readily, allowing for greater dissipation of the imposed punching force. Unfortunately, though, I' well unaware of laws -- perhaps you can figure out to which law such a common sense approach would apply or be applied under. DRosenbach ^{(Talk | Contribs)} 12:21, 30 October 2009 (UTC)

You don't need any of Newton's laws of motion to explain this, although the second is the most applicable. The pain you feel is a result of the acceleration you're subject to when you land. Concrete doesn't give on impact, thus, your acceleration to a stop is very high (because the time for the change in velocity is very short). Per Newton's second law, that's a large force. However, if you jump onto loose sand (note the qualifier), it will shift around impact. That distributes your acceleration over a longer period of time, thus lowering its magnitude and the resultant force you feel. Note that jumping onto hard packed sand would be little different from hitting concrete. In any event, the difference is in how much whatever you impact moves. Newton's laws explain the peripheral factors (why time matters, why you hitting an object is like an object hitting you) but the core reason has nothing to do with them. — Lomn 12:24, 30 October 2009 (UTC)

(ec)I think that's going into way more detail than is justified. Here is a simple explanation:

• $F=ma$ -- Newton's second law says that the force you feel (which is what hurts!) is the mass times the acceleration. The mass is your body mass - but what is the acceleration?
• $v^{2}=v_{i}^{2}+2a(s-s_{i})$ -- Equations of motion says that the final velocity squared (which is zero because you end up stationary) equals initial velocity squared (the speed you hit the ground squared) plus twice the acceleration you're going to feel - times (s-s_i)...which is the distance over which you slowed down.

So, we can simplify that second equation to:

$a=v_{i}^{2}/2d$ where d is the distance over which you slowed down to a stop.

In other words - the force you feel when you hit the ground is your body mass times the square of the speed you hit the ground at divided by twice the stopping distance...and that's the key here. We all know that it hurts more to hit the ground while wearing a heavy backpack (because your mass is larger) and it hurts a lot more the faster you are falling - but what about that stopping distance? A large stopping distance reduces your acceleration compared to a short one. Since landing on solid, immovable concrete forces your feet to slow down in just the distance that the soles of your shoes & feet can be compressed - you only get (let's say) 5 millimeters of stopping distance. But if you land in soft sand, you slow down as the sand gets pushed out of the way. If you leave a 10cm deep footprint - then your stopping distance was 100mm - plus the 5mm for the compression of the soles of your feet and your shoes. That's 21 times more stopping distance in the soft sand. And that means 21 times less force applied to your feet - and considerably less pain!

Of course in reality, it's not just your feet. Hopefully you didn't land with your legs straight and knees locked! Presuming your knees were bent a little then the upper part of your body can slow down over the distance that your knees bend on impact. That softens the blow to your vital organs and brain considerably more than the soft sand does.

This same principle explains why cars are designed with 'crumple zones'. A totally stiff, rigid car would stop in almost zero distance if you drove it into a brick wall. But a well-designed car is designed to crush and crumple selected bits of metal - which allows the car to slow down over a greater distance - hence less acceleration and less force on the poor passengers. The airbag fulfills a similar purpose in giving your head more distance to slow down over than if it hit the steering wheel.

You can explain this in other ways - such as how the energy of the impact is absorbed - but this explanation actually boils down to more or less the same thing - and it's much easier to understand than trying to predict the cohesion of sand grains in loose sand versus sand locked within a matrix of cement.

SteveBaker (talk) 12:25, 30 October 2009 (UTC)

See also Jerk (physics). While your force and acceleration are the same in the two systems, the Jerk is the relevent value that changes, and that changes how damaging the force is. --Jayron32 12:29, 30 October 2009 (UTC)

I beg to differ. The momentum lost is the same in both systems but the acc(dec)elerations are different. Cuddlyable3 (talk) 15:32, 30 October 2009 (UTC)

But it's not the loss of momentum that hurts! You lose the same amount of momentum falling into a big soft pile of feathers as you do smacking into a block of concrete - but the results are most certainly not equivalent. SteveBaker (talk) 16:20, 30 October 2009 (UTC)

Very true. That is why airbags are made for cars, and cute little mini airbags are made for mini cars. Cuddlyable3 (talk) 17:32, 30 October 2009 (UTC)

This question is of great interest to people designing things likes sports and dance floors and playgrounds and there are various standards e.g. EN 14904 for sports floors. Basically we have evolved to have the equivalent of shock absorbers like in a car in our feet and joints. Ours seem to be tuned to running on grass or sand and not to jumping on rocks like goats. This is bad for us as modern streets and buildings typically have concrete pavements and concrete floors with a sheet of vinyl on top. Doing anything except walking on these is dangerous and they can be lethal for the elderly if they fall over. Dmcq (talk) 14:09, 30 October 2009 (UTC)

I'm amazed at the different ways responders formulate a "simple" answer, but not that SteveBaker works a car into the answer. It would only be Wikisensation if he treated a mechanical question without a car. Below is my explanation.
When you jump on concrete it is like the problem of what happens when an irresistable force meets an immovable object? The answer is that at the moment of contact one of them has to give way. Either the concrete has to shatter or (more likely) the foot meeting the concrete has to decelerate to a stop very quickly. Newton's 2nd Law Force = mass x acceleration shows that when acceleration has a large value (deceleration is just a negative acceleration) and mass is the mass of your foot, Force will be large enough to hurt your foot. The rest of your body also decelerates but if you were sensible and kept your knees bent a little, its deceleration is less and continues after the feet have stopped.
When you jump on sand the difference is not just that the sand has small particles, it is also that there is space or water between the particles, allowing them relative movement. Your foot hits the uppermost grains of sand but they cannot resist with as much force as the concrete. The grains are pushed downwards, impacting and rubbing against the layer of grains below. The top layer of grains is now effectively part of your foot and the friction below them is a small Force that gives a small deceleration. So your foot plus sand layer continues downwards a little slower. That impacts the next sand layer layer and so on, and your foot comes to a full stop only after having pushed some distance into the sand. That is a big difference from the near-instantaneous deceleration on concrete. Although the momentum (mass x velocity) that you lose is the same in both falls, in the fall on sand the Force of deceleration has been spread in time so its maximum value is less hurtful. Jump down on to a mattress and the deceleration is even less and the experience not hurtful at all. Cuddlyable3 (talk) 15:28, 30 October 2009 (UTC)

I have always wondered, since the law of conservation of energy is true, once your foot hits the concrete, where does the energy form acceleration go?Accdude92 (talk to me!) (sign) 15:31, 30 October 2009 (UTC)

Heat, sound (which soon dissipates into more heat) and breaking stuff (pulling apart the bonds between the atoms of the material). SteveBaker (talk) 16:17, 30 October 2009 (UTC)

To the OP, your Sir was right. In fact all 3 of Newton's Laws can be seen at work during the jumps. Energy is conserved but there is good work-producing energy and lazy good-for-nothing workshy energy. Before you jump down on anything, consider that your potential energy is a Non-renewable resource whose expenditure causes by the Second law of thermodynamics an increase in Entropy thereby hastening the Heat death of the universe.Cuddlyable3 (talk) 17:20, 30 October 2009 (UTC)

Interestingly enough the 5mm that SteveBaker used as a minimum is actually about the very minimum deformation a floor should have to avoid the main danger of an old person breaking their hip if they fall over. It's quite small. a full centimeter is much better but I think it shows the way our ancestors evolved to just about be safe on the plains in Africa without spending too much resource on over protection. Dmcq (talk) 23:09, 30 October 2009 (UTC)

Yeah, the Savannah Hypothesis is pretty much disproved these days, as much as such a thing can be. It's tempting to make up just-so stories to explain observations about humans, but we should be cautious: what's the minimum deformation a floor should have to avoid the main danger of an old chimp breaking their hip if they fall over? What about a cat? What about a kangaroo? Is there any reason to believe these are significantly different? 86.139.237.128 (talk) 00:13, 31 October 2009 (UTC)

We have evolved to run and walk whatever about what hypothesis or collection of them that is under. If we needed to jump around rocks like goats we'd have evolved much better shock absorbers in our legs and joints. Chimps don't have as much problem as us on the ground because they aren't as tall and their bones are far stronger than needed just for support. Humans however are built more for lightness and endurance than strength. Dmcq (talk) 16:26, 31 October 2009 (UTC)

The Verity Incident

What was the Verity incident? Theallwordslinkedtalkman (talk) 16:27, 30 October 2009 (UTC)

Googling the exact phrase "Verity incident" only turns up 10 hits, and they aren't all for the same event. And verity can mean a lot of different things. So it'd be hard to answer this question without the context in which the phrase was used. Red Act (talk) 16:49, 30 October 2009 (UTC)

It was an incident where a fugitive was arrested at gunpoint at a school, reported here and here. Cuddlyable3 (talk) 17:28, 30 October 2009 (UTC)

Do you by chance mean the Vela Incident? Googlemeister (talk) 18:22, 30 October 2009 (UTC)

If I were small enough could I observe an atom?

If I were as small as an atom could I watch its operation? Presuming there is a reality down there, would the atom be observable by a hypothetical supertiny person? Such a person could obviously not exist so this is a thought experiment. What would we see given the extreme speeds of the particles, their being point-like and I believe the particle’s speeds and position are undetermined until measured. Thanks for any thoughts (I suspect the question has no answer!) - Adrian Pingstone (talk) 18:47, 30 October 2009 (UTC)

The biggest problem is that the wavelength of light is larger than the atom, so you couldn't see anything, including yourself, if you were that small. Otherwise, it would be possible to observe the movement of nuclei, and probably observe how the electron "clouds" behave in bonds, individual atoms, ions, etc. but due to the speed of the electrons' movements, you would be unable to observe individual electrons. The Seeker 4 Talk 19:13, 30 October 2009 (UTC)

Indeed, the problem is not that you are too big. The problem is that the resolution of light is inadequate. See "Microscopy", "Optical microscope" and "Electron microscope". The limit of resolution with light is about 200 nanometres. Axl ¤ [Talk] 20:00, 30 October 2009 (UTC)

These arguments are somewhat vague, as there exists near-field optics; also see the pages on near and far field, near-field scanning optical microscope and Near Field Communication (unfortunately, most of the articles are not very good, but you can check from journals that the idea works). The usual diffraction limits are calculated using the wave optics approximation to the Maxwell theory, an approximation that breaks up in the near-field case. Now on the original question: what should the hypothetical person consist of? Seeing means interaction between photons and the person's eyes, and the eyes' sensitivity depends on their composition. — Pt _(T) 20:31, 30 October 2009 (UTC)

One thing you could do is feel individual atoms, using the principles used by the atomic force microscope and the scanning tunneling microscope. Note that individual atoms are visible in the images in those articles. Red Act (talk) 20:45, 30 October 2009 (UTC)

Not only that but if you were really that small, brownian motion would beat the heck out of you! You'd better hope it's really cold! SteveBaker (talk) 22:16, 30 October 2009 (UTC)

I think it's actually the Heisenberg uncertainty principle more than anything else that limits the ability to observe an atom on a fine scale -- it says that the more precisely you know the position of an object, the less precisely you can know its velocity. This basically means that regardless of your size you can't know the fine details of an atom's motion. Looie496 (talk) 23:03, 30 October 2009 (UTC)

You can see as precisely as you want, but you have to choose beforehand, what exactly you are going to look at. You can measure the position of a photon exactly, but then you cannot know the momentum (p) of the same photon and, as E=hν=pc, you neither know its frequency (its colour). Thus you have to choose at least one of bad spatial resolution and colorblindness. The same applies for any other pair of observables corresponding to noncommuting operators in quantum mechanics. However, if you decided to measure only colours, it would definitely be an interesting picture. At another time you may as well watch the spatial dynamics of the photons reaching your eyes. Quantum mechanics does not make everything blurry, it just bites when you want to learn too much at a time! — Pt _(T) 23:33, 30 October 2009 (UTC)

Actually, for such a small observer the whole concept of measurement changes as there the usual macroscopical decoherence does not happen anymore. The observer herself is a quantum object and we have no idea what a quantum consciousness in a notable superposition would sense. Note that the quantum mind is a different concept applied to try to explain the usual, macroscopical consciousness. It is all speculative indeed. — Pt _(T) 00:46, 31 October 2009 (UTC)

You could not "see" things if you were a human as small as an atom, because you would be far smaller than a single rod or cone light receptor in the retina, and you would be far smaller than a single nerve cell in the human visual cortex. For the scheme to work, you would have to hypothesize that you and all your organs were made of atoms many orders of magnitude smaller than the atoms you were observing. The converse would be, "If an atom were as big as a bus, could I watch its operation?" In that case you might have to hypothesize the giant atom having physical constants such as Planck's constant and the strong and weak nuclear forces and electrical constants many orders of magnitude different than in our universe. Edison (talk) 01:16, 31 October 2009 (UTC)

You need little teeny eyes/for reading little teeny print/like you need little teeny license plates for bees. --Trovatore (talk) 01:18, 31 October 2009 (UTC)

As the question is phrased, you obviously meant for us to take it in a COMPLETELY non-literal fashion. Being so small, nothing in your body would work -- what would you consist of if you were small enough to see an atom? The lumen of your digestive system would be microscopic, as would the lumina of your ureters and your blood vessels. Even cells would be too large to traverse your circulatory system -- I mean, the ramifications are so many, it's somewhat ridiculous to even begin listing them here. I therefore take your question to mean, "Should an atom be able to be visualized in real time, would the observer be able to perceive the various motions ascribed to, for example, the orbiting motion of the electrons." For my purposes here, and hopefully for your purposes as well, just as I am ignoring all the infinite problems associated with the viewing organism being too small to possibly be able to exist, so too am I ignoring all integral problems related to light microscopy and the possibility of viewing items less than the diameter of a wavelength of light -- for certainly, you would not be interested in a similar response pertaining to adjunct obstacles in the vieweing of an atom, such as, "well, you wouldn't be able to view an atom because, if you were so small, you'd be in the circus and wouldn't have time to look at atoms. Thus said, perhaps the editors involved above can focus on such a question -- if you're still interested and my assumptions were correct. DRosenbach ^{(Talk | Contribs)} 17:27, 1 November 2009 (UTC)

This is the OP writing: DRosenbach is exactly correct, I was indeed imagining that I was actually down there at the atomic level with eyes and other senses that can still function. I would love to receive any more ideas - Adrian Pingstone (talk) 22:23, 1 November 2009 (UTC)

Small populations sizes and genetic mutations

When a tribe is discovered in the jungle or a new group of people are found on a remote island, I assume they have a greater amount of genetic drift which presumably results in more frequent mutations. Are there any recorded cases of a small population being discovered and all the individuals involved having some kind of beneficial mutation? I'm no scientist so please try and answer in a way I can understand.Popcorn II (talk) 19:33, 30 October 2009 (UTC)

There won't be more mutations; a mutation happens in an individual, so it doesn't matter what's happening in the rest of the population. Genetic drift will result in them having different allele proportions from the population they split off from. In a small population it, combined with the founder effect, will result in reduced genetic diversity. That means it is quite likely that a small isolated population will have every individual having a particular allele, and that allele could easily be a beneficial one. (Few alleles that aren't shared among all humans are beneficial to everyone, otherwise they would become shared among all individuals, but a certain allele may be beneficial in their environment - that is now evolution works.) --Tango (talk) 20:00, 30 October 2009 (UTC)

There are clear examples of adaptive characteristics found in isolated populations (though I'm not sure that any have been mapped to a single causative mutation). One potential example is the Moken, whose children have remarkable underwater vision. Its not known whether their superior underwater vision is a genetic or learned trait since one can learn to accommodate one's visual focus underwater, but rarely to the extent commonly seen in Moken children. But its certainly beneficial, given they spend much of their time diving for food. Rockpocket 20:24, 30 October 2009 (UTC)

The Moken's underwater visual abilities are probably learned [1]--Gilisa (talk) 22:54, 31 October 2009 (UTC)

Ah yes, it turns out their follow up study showed that other children can adapt just as well with the correct training (PMID 16806388). What a shame, when I first read their paper back in 2003, it hinted at a beautiful example of an adaptive genetic characteristic. Rockpocket 00:53, 1 November 2009 (UTC)

Flu vs. other diseases

How deadly is influenza compared to other infectious diseases? In particular, what other parasites cause similar numbers of deaths in, say, the U.S.? Thanks. 66.65.140.116 (talk) —Preceding undated comment added 20:05, 30 October 2009 (UTC).

According to the article Influenza vaccine, a report in 2008 cited that influenza accounted for about 41,000 deaths annually in the U.S. Worldwide figures can be found at Infectious disease#Mortality from infectious diseases, and influenza is counted there as part of a class called "lower respiratory infections", mixed in with things like pneumonia and stuff. So "flu-like" diseases are the largest cause of death from infectious agents worldwide, but I am not sure how this compares once you strip out the numbers for Influenza directly. Doing so would likely be impossible, since there are many non-influenza agents which cause nearly identical symptoms as influenza, and worldwide there is probably not the testing availible to seperate these. Diagnoses of "death from the flu" is probably made on a symptomatic basis, and as such, the best we can get on hard numbers would be "lower respiratory diseases". --Jayron32 20:18, 30 October 2009 (UTC)

If you're talking about mortality rate, flu is not terribly high on the list; it does get a high number of total deaths, though, in part because you can keep right on getting influenzas until one of them finally punches your ticket. Diseases with a very high rate of mortality include (in no particular order): HIV, Ebola, and untreated rabies (which, I think, was essentially at 100% until a small handful of people managed to pull through. Also, although their affects in humans may sometimes be quite similar, viruses and bacteria and generally not called parasites; that term is usually reserved for multicellular lifeforms. You may be interested in our article on List of causes of death by rate. Matt Deres (talk) 04:56, 1 November 2009 (UTC)

Tramadol expiry dates

Why do painkillers like tramadol carry an expiry date after which the instructions say you should not take them? Do they stop working? Or become dangerous? Or something else? Why? 86.166.155.90 (talk) 20:55, 30 October 2009 (UTC)

Generally the chemicals are not 100% stable and eventually break down, giving rise to byproducts which may or may not be harmful. Looie496 (talk) 21:04, 30 October 2009 (UTC)

Usually drugs just lose their effectiveness, but it is possible that the active ingredients, or one of the non-active ingredients that they use to make the bulk of the pill, will become potentially harmful. --Tango (talk) 09:32, 31 October 2009 (UTC)

About 2 yrs ago, I read an article on one of the common household NSAIDs and it mentioned that independent testing of the drug showed it was stable more than 2 years after the expiration date. The article suggested that expiration dates are as near as they are merely because the drug companies have only done testing for that long (e.g. 5 years). DRosenbach ^{(Talk | Contribs)} 00:02, 1 November 2009 (UTC)

A cynic might point out that keeping the period short sells more Advil. --Sean 13:41, 2 November 2009 (UTC)

October 31

Foreign accent syndrome and stroke recovery

I was curious about a case I read about a few years back, regarding a patient who had what, after searching here, I discovered to be foreign accent syndrome. It got me to thinking - if, after a stroke or other brain injury, in rare cases people can speak only in an accent, have rehabilitation workers ever experimented to see if a person who has lost their speech might recover it if taught to speak differently?

I'm aware there might be some flawed biology I'm not catching, but: If a person's neural patterns are such that they can't do the numerous things necessary to form speech, could there still be some mechanism that would let them produce it differently? could those with FAS speak that way because, in essence, they have "relearned to speak," in the same way a child learns to speak in his or her own unique voice? (Since every voice, even without an accent, sounds a bit different.)209.244.187.155 (talk) 00:32, 31 October 2009 (UTC)

Reading your question, I think you've missed that the people aren't really speaking in a foreign accent. It isn't that they've learnt to speak in a different accent, it's that brain damage affects how they pronounce some sounds in a consistent manner. People who hear them interpret this as them speaking in a foreign accent. For example, someone who previously had a rhotic accent might suffer brain damage that affected their ability to pronounce the 'r' in words like 'Arthur'. Their friends and family, who also speak with rhotic accents, perceive this as them speaking a non-rhotic accent (like many British accents). 86.139.237.128 (talk) 02:32, 31 October 2009 (UTC)

Okay, you're right, that's what I was getting confused by; thanks.4.68.248.130 (talk) 09:15, 31 October 2009 (UTC)

Stroke symptoms can be very strange, and it's hard to predict what might or might not be possible. There are, for example, cases of people who have lost the ability to talk but are still able to sing. Looie496 (talk) 04:27, 31 October 2009 (UTC)

I heard from the Media about one Czech turist who had traumatic brain injury after falling from his bike in London. Then, when he woke up in the British hospital he start speaking in fluent English with British accent, something he certainly couldn't done before. So, it seems like the brain could be very flexiable sometimes (but not always). For instance, it seem like the visual cortex of people who lost their sight is being used extensively for the sense of touch -this ability of the brain to gain new functions or to rewire itself isa part of its neural plasticity. But what you asked is more complicated, as we are talking about something more complicated than sensing-language is learning dependent high function and it can't appear out of the blue. So it seem much more similar n to one regression to his/hersecond language, that happened many times during degenerative diseases such as Parkino's disease. That is, one major function is lost, so the brain must use the more preserved areas and the previously dominant brain areas can't longer overpower/inhibit the areas that contain these secondary abilities.--Gilisa (talk) 17:39, 31 October 2009 (UTC)

I am glad he survived. It is sad to see a Czech bounce. Cuddlyable3 (talk) 12:43, 1 November 2009 (UTC)

Increasing the size of the human penis?

Is there any medications available that actually work to permanently increase the size of the penis? —Preceding unsigned comment added by 84.68.36.19 (talk • contribs)

• No. --Jayron32 01:23, 31 October 2009 (UTC)

We have an article on that: Penis enlargement. Red Act (talk) 01:35, 31 October 2009 (UTC)

No. [2] —Preceding unsigned comment added by 79.75.106.210 (talk) 01:50, 31 October 2009 (UTC)

You wouldn't enjoy permanent enlargement this way though there is a popular temporary way. Cuddlyable3 (talk) 14:40, 31 October 2009 (UTC)

I always get e-mails that offer me to buy enlargement kit-all I have to do is to give my address and c. card number and a simple kit will be sent to my post office box. I never tried it, but maybe you want me to give you connection details?--Gilisa (talk) 18:12, 31 October 2009 (UTC)

With all due respect, I hope you're kidding Gilasa. Let me put it this way: if the information is in your spam box, the information fails being trustworthy as soon as your credit card information changes the outcome. Magog the Ogre (talk) 20:12, 1 November 2009 (UTC)

Nifty Propulsion Device

Someone pointed this thing out to me [3] and I don't know enough physics to determine whether it makes sense. Can someone who knows more about it give a ruling? Black Carrot (talk) 04:45, 31 October 2009 (UTC)

This is the EmDrive. As a reactionless drive, it blatantly violates the conservation of momentum and cannot work as claimed. After the magnetron is turned on, the microwaves aren't going to do anything except bounce around and get absorbed with absolutely no effect on the cavity's total momentum. The energy will then be radiated as blackbody photons, though asymmetries in the device's geometry may provide a miniscule force on the "drive". In other words, the "drive" will function much better if the end facing the magnetron is removed, because the photons will then serve as a tiny reaction mass. --Bowlhover (talk) 06:36, 31 October 2009 (UTC)

Someone who knows more about it has given a (rather damning) ruling, and you can see it here: [4]. The basic error Shawyer makes is to assume the impulse imparted on a wall during a particle-wall collision is in an incorrect direction. You can see this yourself by looking at figure 2.4 of [5] (an earlier version of the same document). In the "updated" version, Shawyer removes the section which makes his error obvious. Someone42 (talk) 07:00, 31 October 2009 (UTC)

Roger Shawyer claims[6] to have calculated and measured on a demonstrator engine 16mN thrust from an input power of 850W. Dr. Costella[7] accuses Roger Shawyer of being a charlatan who defrauded a government agency (the UK Department of Trade and Industry). I smell a libel suit where lawyers are bound to earn. Cuddlyable3 (talk) 14:35, 31 October 2009 (UTC)

The only real test will be when someone actually takes his device up into orbit and it moves.When is this going to happen?80.0.98.26 (talk) 11:14, 1 November 2009 (UTC)Trevor Loughlin

Hopefully never, because that would cost a lot of money and I would hope that the people who control such quantities of money would do a bit of investigation before giving it away. Seriously, the guy is a complete idiot (or a con man). He doesn't even claim some hitherto undiscovered law of physics, he claims that his drive works in the framework of standard electrodynamics. But it's a theorem that momentum is conserved in electrodynamics (Noether's theorem), so he's wrong and that's the end of it. The most valuable thing about this fiasco is that it's a lesson in just how far New Scientist's journalistic standards have fallen. It's barely above the level of a supermarket tabloid at this point. The problem isn't so much that it's a terrible magazine—there are lots of those—but that people still trust it as a source of physics news. It's disturbing how often it gets used as a reference in Wikipedia articles. Greg Egan wrote a plea to save New Scientist in the wake of this story, but I think it's too late for that. I would instead plead with people to cancel their subscriptions. -- BenRG (talk) 13:23, 1 November 2009 (UTC)

Dry friction

What actually is dry friction? Can i call viscosity as fluid friction and vice-versa ? —Preceding unsigned comment added by 122.168.213.193 (talk) 11:17, 31 October 2009 (UTC)

Not really. Dry friction is the lateral friction between touching surfaces of solids, and may be classified as either static or dynamic depending on whether the surfaces are stationary or moving relative to one another. Viscosity is the resistance of a fluid to flow, and whilst the name "fluid friction" sounds appropriate, it's ambiguous as the term is already taken to be the friction between two solid surfaces separated by a fluid, or sometimes the friction between layers of a fluid with relative motion to each other. See this.--Leon (talk) 13:55, 31 October 2009 (UTC)

Area dependency of friction

It is stated that frictional force is independent of area of contact then why we fell it harder to ride a bicycle with flat tire (air less) —Preceding unsigned comment added by 122.168.213.193 (talk) 11:26, 31 October 2009 (UTC)

First let me point out (before Steve Baker starts jumping up and down) that that description of the friction force as independent of the area is intended for non-sticking flat hard surfaces. Tires don't meet those criteria. More importantly, though, you are confusing rolling friction (on the bike's tires) with sliding friction (which is the kind of friction this description is intended for). Dauto (talk) 11:34, 31 October 2009 (UTC)

Sliding is not a factor. Squashing and unsquashing the rubber of a flat tyre consumes (i.e. converts to heat) energy, see Rolling resistance, that must be provided by the rider. Cuddlyable3 (talk) 14:11, 31 October 2009 (UTC)

A noise meter to measure outdoor road noise pollution in the UK?

Noise or sound meters are less expensive than I thought, and buying is cheaper than hiring. I want to measure outdoor road noise pollution, in a way that complies with UK standards for doing so - whatever they are. I think this requires using an "A" digital frequency filter, which seems available on many meters. But rather than looking at a fluctuating meter and mentally trying to average the reading, are there any meters that will do this automatically - that will tell you what the average reading was over a minute say? Since I will avoid rainy situations a waterproof meter is not necessary. Thanks 78.144.206.114 (talk) 11:37, 31 October 2009 (UTC)

It sounds (pun) that you want to measure A-weighted long-term average sound level as defined in BS 7445 / ISO 1996. Look for a noise meter that has an analog or digital logging output that you can connect to a PC. If it is analog then you need an A-to-D converter. THe PC can store the data, calculate average(s) and show them on a spreadsheet. A common mistake made by professionals who should know better is to take an average of dB(A) measurements. This is wrong because dB (decibel) is a logarithm of a power measurement. The correct way is to convert from the dB(A) values to power(A) values, take their average, then convert back to dB(A). For the legal background in the UK see [8] the Noise and Statutory Nuisance Act 1993 and the EU Environmental Noise Directive. Cuddlyable3 (talk) 14:05, 31 October 2009 (UTC)

Thanks, although where I want to take the noise readings will be a very long way from my desktop computer. Are there any that can do the "averaging" themselves? Thanks. 78.151.126.29 (talk) 21:35, 31 October 2009 (UTC)

Consider using a portable Laptop or Netbook. Battery time is a limitation. Cuddlyable3 (talk) 22:05, 31 October 2009 (UTC)

Cicely of Oxford Royal Physician

I read somewhere that Cicely of Oxford was Court Physician to either Richard II or England or Edward III of English. Is there any way to confirm this? —Preceding unsigned comment added by 76.200.166.39 (talk) 11:51, 31 October 2009 (UTC)

Both [9] and [10] claim that she was Court Physician to Edward III, although neither look particularly reliable. The whole claim looks rather doubtful, as I cannot find any other references to Cecily or Cicely of Oxford, and historical works which would have been expected to mention a fact so interesting as a fourteenth-century female physician (e.g. this survey of royal physicians in the reign of Edward II and immediately after) don't have anything to say about it. Warofdreams talk 23:06, 31 October 2009 (UTC)

P. C. Doherty is a pretty bad writer of detective stories, but he has strong academic credentials as a 14th century history, so if he claims Cicely of Oxford was physician to Edward III, he probably has a good basis for saying so. Looie496 (talk) 02:49, 1 November 2009 (UTC)

Epidermal growth factor

Hi I'm a little confused about how epidermal growth factor (EGF) is produced in the human body. Are there cells that produce it? The article on EGF says 'sources' are macrophages, platelets, urine, plasma and milk. What does this mean? Do macrophages and platelets produce EGF? I can't imagine urine/milk producing anything, or does it mean ingesting urine/milk would provide a person with a source of EGF? Any clarification would be great, thanks RichYPE (talk) 14:20, 31 October 2009 (UTC)

I think you have to go to the cited source of the information which is Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease. St. Louis, Mo: Elsevier Saunders. ISBN 0-7216-0187-1.Cuddlyable3 (talk) 21:33, 31 October 2009 (UTC)

Epidermal growth factor is a protein, and as such is produced by protein synthesis, which occurs in cells. The megakaryocytes that give rise to platelets, synthesize EGF (see this paper, as do macrophages. When EGF is found outside of cells, it is because it has been secreted from the cells that produced it. --NorwegianBlue ^talk 11:12, 1 November 2009 (UTC)

Hydrocephalus

good evening, I just want to ask about hydrocephalus.. i am a Physiotherapist, and i have a patient who have one, my main concern is that she keeps on crying while the therapy is on going, and im afraid if this is bad or dangerous to her, sometimes she turns cyanotic.. hope you can help me and also I want to know what technique can i improve her trunk control for she will be able to sit and walk independently... waiting for your response": Erlinda M. Mendoza —Preceding unsigned comment added by 120.28.71.159 (talk) 15:46, 31 October 2009 (UTC) —Preceding unsigned comment added by 86.4.186.107 (talk)

Erlinda, I'm sorry but we don't give medical (or physiotherapy) advice on the Reference Desk. Receiving medical advice from strangers for the treatment of a third person is very risky, I'm sure you can understand this. If you are a chartered or qualified physiotherapist you must surely have professional colleague or seniors who can give you advice. Of course we have an article on hydrocephalus, reading this might be helpful. Caesar's Daddy (talk) 16:04, 31 October 2009 (UTC)

Sounds of a Teaspoon in a Mug of Milk?

Take a mug of milk (or milky tea, or milky coffee). Heat it. Take a teaspoon, and tap it on the base of the mug (but from inside the mug, like you're stirring it.) Listen to the sounds, specifically the pitch of the sound. WHAT CAUSES THIS? ASCII image related.

   |
#  |   #
#--|---# Teaspoon in a mug with hot milk,
#  |   # move it up and down, tapping mug base,
#  |   # what the hell are the sounds like that for?
# ( )  #
########

No answers from anyone what has not tried this please. Remember Civility (talk) 19:01, 31 October 2009 (UTC)

Before putting in the milk the mug gave out a tinkle, effectively acting as a bell. As the milk went in the resonant frequency went up because of the smaller part of the mug that can resonate freely, but changed progressively from a tinkle to a dampened knock sound. Then I drank the milk yum-yum. Cuddlyable3 (talk) 21:28, 31 October 2009 (UTC)

That's "Original Research", I'm not sure that's allowed ;-)) Richard Avery (talk) 22:45, 31 October 2009 (UTC)

YOU DIDN'T TRY IT DID YOU? :p Take a full mug of milk. Tap. Listen to that sound. Tap again (not adding or removing any fluid). Listen to that sound. tap - tap - tap - tap - tap - tap - tap - tap, listen to the sounds of the taps. No liquid added or removed. Remember Civility (talk) 22:49, 31 October 2009 (UTC)

I tried it with a heated mug of water (my girlfriend drinks milk, but there's none in the fridge at the moment), and it sounded quite unremarkable. There are a lot of variables here that will affect what is heard with this experiment -- the thickness, shape and material of the mug, how full the mug is, the acoustic properties of the surface the mug is placed on, possibly the thermal properties of the liquid, mug, and surface, since the liquid is heated, etc. Could you please record the sound and upload it, so we can hear whatever it is you're hearing? Decent laptops nowadays have built-in microphones (even if you can't necessarily see where it is), it's easy to record using the Sound Recorder that comes with Windows, and I think it's fairly straight-forward to upload a file using the "Upload file" link under the "toolbox" section of this page. Red Act (talk) 01:34, 1 November 2009 (UTC)

As someone who has heard this noise, I can tell you that what causes this is the same thing that causes any sound. When the spoon hits the mug, the spoon and mug vibrate. The milk in the mug affects the vibrations of the mug and the spoon, and what you hear is a combination of all the vibrations. See sound —Akrabbim^talk 01:04, 1 November 2009 (UTC)

Most of the respondents don't seem to have noticed the phenomenon that I think Remember Civility is referring to: correct me if I'm wrong, RC, but I believe it is that when the mug is tapped, the pitch of successive taps progressively rises for a time. I've noticed and wondered about this when stirring hot tea or coffee: at first I assumed it was due to the rising temperature of the mug (due to heat transfer from the beverage) altering its acoustical properties, but it also seem to happen if one waits long enough before stirring for the beverage and mug temperatures to have stabilised. An alternative conjecture is that tapping (or stirring) releases dissolved gasses in the beverage, altering its density and therefore acoustical properties. I too would really like to know the correct answer to this. 87.81.230.195 (talk) 06:35, 1 November 2009 (UTC)

I haven't tried this (not a tea drinker), but I've certainly noticed something which might be similar. If you fill a glass with hot water from the faucet, and drop some silverware in, it rattles with a sound which I would describe as a knock or a tap. But a few minutes later, if you jiggle the silverware around, the sound is much more tinkly. (And I notice this phenomenon all the time, when I'm soaking the glass and the silverware prior to washing them.)

There's something else I notice. When I first run the hot water into the glass from the faucet, it's cloudy. A few minutes later, when the sound has changed, the appearance has changed, too -- now the water is clear.

You can probably see where I'm going with this, and it's the same suggestion 87.81.230.195 made already. Hot water fresh out of the tap contains a lot of dissolved gases. The dissolved gas seems to quite significantly muffle or deaden sound. It takes a few minutes for the gas to come out of solution, and when it does, both the appearance and the sounds are much clearer. —Steve Summit (talk) 14:35, 1 November 2009 (UTC)

I'm fairly certain the cloudiness is due to temporary hardness (not dissimilar to the limescale in the kettle). Whether this has an effect on the noise, I'm not sure, but it's possible. - Jarry1250 ^{[Humorous? Discuss.]} 15:35, 1 November 2009 (UTC)

editors who've noticed the rising pitch are correct. I didn't want to mention it for fear of "planting" the thought. I've done a bit more search and it is mentioned in an old [i]New Scientist[/i], see this link, and then, 14 years later, they have another, fuller, bit of text. Note that stirring can "reset" the sound back to a lower pitch. Remember Civility (talk) 15:33, 1 November 2009 (UTC)

I just did some original research regarding this question, in a very literal sense of the phrase: I have now tried this three times with pure boiling hot water, and three times with boiling hot water with cocoa powder in it. All three times pure water was used, there was no discernable rise in pitch. All three times cocoa powder was used, there was a rise in pitch.

The third time each way was done simultaneously, and performed identically except for the cocoa powder: I brought identical amounts of water in identical mugs to a boil at the same time in a microwave oven. I moved the two mugs simultaneously from the microwave to adjacent tiles on the same countertop. I poured some cocoa powder into one of them. I stirred both mugs simultaneously with identical teaspoons briefly, and then simultaneously held the two spoons in a bottom corner of their respective mugs briefly, to essentially eliminate the swirling motion of the liquid in each. I then repeatedly tapped the bottom centers of the mugs with the spoons in alternating order. The pitch in the pure water, to the best of my hearing ability, stayed constant. The pitch in the cocoa started off considerably lower than in the pure water, and ended up if anything slightly higher. In neither case did bubbles come to the top of the liquid during the tapping process.

It certainly appears to be quite important that there be a solute in the water. However, it isn't necessary for the solute to be milk, as the OP suggests, since the cocoa powder I used does not contain any milk. The cocoa powder I used was Ghirardelli Sweet Ground Chocolate and Cocoa, which contains sugar, cocoa (processed with alkali), unsweetened chocolate, soy lecithin and vanilla.

The "tiny bubbles" hypothesis put forward by Cecil Adams[11] seems dubious to me, as I could not see any bubbles reaching the surface of the liquids during the tapping process. And the "changing vortex" hypothesis[12] doesn't make sense, either, because the liquid was essentially stationary in both mugs during my final experiment. Red Act (talk) 17:57, 1 November 2009 (UTC)

If stirring the liquid really does "reset" it - then it has to be something to do with the vortices (or lack thereof). Bubbles might be knocked out of solution by stirring - but it's hard to imagine that more could be added - hence stirring couldn't reset things if bubbles were the cause. Stirring won't reset the temperature - so the effect of gradual cooling can't be the cause either. The idea that the liquid has to be moving in some specific manner probably accounts for some of what's going on. Sound waves will get dragged around with the fluid - so you could imagine different resonant pathways in rotating fluid versus stationary. Using a curved spoon to do the tapping will certainly start up some motion of the liquid - and that might easily be "reset" by stirring. Changing the ingredients of the liquid would change viscosity and perhaps the speed of sound - so it should be no surprise that this is a determining factor. SteveBaker (talk) 22:00, 1 November 2009 (UTC)

How about this for a hypothesis: Suppose the liquid is spinning (eg after stirring) in a smooth, circular path with more or less laminar flow. In stationary liquid, the sound from a tap made in the center would travel radially outwards until it hit the side of the cup - but in a spinning liquid, it has to travel around in a spiral. This changes the distance it has to travel thereby altering the resonant frequency - and also alters the angle at which the sound waves hit the side of the cup changing refractive patterns of the sound through to the air outside. Either of those things could change the pitch that you hear. However, because you're using a complicated curved spoon to do the tapping, each movement of the spoon causes turbulant eddies to spin off from it. Progressive taps cause more and more turbulance - and after enough taps, the spinning of the liquid is broken up into much more random motion at small scales and very little laminar flow - resulting in approximately equal travel times for the sound. Stirring the liquid restores the large-scale laminar flow and allows the experiment to be repeated.

Suggested experiments:

1. Try tapping with a thin, cylindrical object (a glass rod would be perfect) - trying to keep the rod in the center of the cup. This ought not to disturb the flow of the liquid so much - so (if my hypothesis is correct) it should take many more taps to mess up the flow rate and get the pitch of the sound to rise.
2. Try messing up the flow of the liquid with random motions of the spoon instead of smoothly stirring it. If the hypothesis is correct, this should immediately "reset" you to the highest sound frequency instead of the lowest.

SteveBaker (talk) 22:11, 1 November 2009 (UTC)

November 1

Numbering of Magicicada broods

Why are the Magicicada broods numbered the way they are? For Brood I (for 17-year cicadas), the year number of emergence leaves a remainder of 6. Why not 1, or 0? —Preceding unsigned comment added by 75.37.158.42 (talk) 04:16, 1 November 2009 (UTC)

They are probably numbered after the first year someone started numbering them. But the numbers are clearly intended to be fairly arbitary because they numbered the 13 year cicadas with the next available numbers after the 17 year variety. I don't think there is anything particular to read into the choice of numbers. SteveBaker (talk) 21:52, 1 November 2009 (UTC)

They're prime numbers, making it very hard for a predator on a shorter cycle to track to the cycle of the cicadas.[13] Fences&Windows 02:46, 6 November 2009 (UTC)

Oh, whoops, that wasn't the question. The numbering of the broods by Charles Lester Marlatt in 1907 was arbitrary, but it stuck. Fences&Windows 02:56, 6 November 2009 (UTC)

What specific type of foam is this? (Think tool/bike grips)

Can't find a definitive answer on this anywhere. There are two specific materials I can't identify that I see used in handles/grips of all kinds; ex: tools, fishing rods, bike handlebars, etc..

The first one is in tube form, with an 1/4" wall. It feels squishy and soft (firmer and deforms less than visco-elastic foam) and has a somewhat rubbery feel. The inside of the tube is smooth and shiny like neoprene you'd fnd in a wetsuit or gasket, and the outside has a matte, smooth texture that I assume makes this open cell foam. The second material is similar, except the cell size is much larger, and thus the texture is more 'pebbly' as. It is in a sheet 1/4" thick.

Other than that (admittedly) poor description, all I can add is: the material isn't 'plasticky' feeling like extruded polyurethane tubing for pipe insulation, nor is it low-density like polyurethane foam for upholstery. It's also not so dense that it'd hurt you if someone threw a chunk at you.

Looking around, the likely suspects I've found across were EVA and a PVC variant (may be a trade name) called NPVC. Neoprene also, but I rarely see it in the thicknesses used in these products, or with any texture. So, does anyone know exactly what I'm talking about? Please don't say foam rubber. That much is obvious :) Thanks in advance.

KA - 97.82.253.69 (talk) 04:28, 1 November 2009 (UTC)

NPVC stands for Nitrile PVC. It is pretty much the standard for foam grips. There are many variants of it because it is easy to adjust the formula when producing the grips. -- kainaw™ 04:39, 1 November 2009 (UTC)

I couldn't have asked for a better answer. Many thanks. 97.82.253.69 (talk) 09:29, 1 November 2009 (UTC)

Power vs frequency

Why does the power/torque of an Internal Combustion engine depend on its RPM? —Preceding unsigned comment added by 116.90.224.116 (talk) 07:00, 1 November 2009 (UTC)

You can answer that loads of ways but basically RPM gives the rate at which fuel is burned (RPMxnumber of cylindersxamount of fuel per cylinder) or alternatively the number of explosive pushes by the cylinders which the engine harnesses. So at low RPM power is proportional to RPM but at high RPM the efficiency falls away for several reasons. If you give the approx level of the question it is easier to pitch the answer. --BozMo talk 09:55, 1 November 2009 (UTC)

For the same reason that you have to breathe faster to run faster. Cuddlyable3 (talk) 12:34, 1 November 2009 (UTC)

I'm going to do some simplifying here, but broadly what I'm saying is correct. Torque depends on RPM because the engine isn't equally efficient throughout its rev range. At low revs engines typically do not fill and empty the cylinders efficiently. At high revs it's often the case that the valve openings are too small to allow the combustion gases in and out of the cylinder fully. As a result, maximum torque is often somewhere in the middle of the engine's rev range. Power is given by torque multiplied by revs, so, if the torque was constant over the rev range, power would linearly increase with revs. Since torque drops off at high revs, we find that power will eventually do so as well, but because of the rev multiplier, it's always higher up in the rev range. --Phil Holmes (talk) 18:58, 1 November 2009 (UTC)

lightening shock

if electricity is been harnessed from lightening why does the rain water that flows from the same place conduct? what s the mechanism behind that? —Preceding unsigned comment added by Srividhyaathreya (talk • contribs) 08:02, 1 November 2009 (UTC)

Each little drop of water carries a small static charge. Electricity is not being conducted in the normal sense of electrons flowing in a medium, but though the bulk travel of charged drops. The air only conducts when a high voltages starts to cause a breakdown. Graeme Bartlett (talk) 10:59, 1 November 2009 (UTC)

career

i m an electrical engineer from India. i wish to enter into the field of space science. can i pursue an m.e or m.s. in aerospace engineering. if not what is the apt course to become an astronaut or a space scientist? —Preceding unsigned comment added by Srividhyaathreya (talk • contribs) 08:05, 1 November 2009 (UTC)

I would expect that you may be employed as a support person, however to be an astronaut, you should qualify as an aircraft pilot first. As a space scientist, you had better get a PhD in physics. Graeme Bartlett (talk) 10:56, 1 November 2009 (UTC)

You don't need to be a pilot to be an astronaut. Pilots of spacecraft will generally be pilots, but there are scientists and engineers that become astronauts too. I would expect a PhD is required to do scientific research in space. --Tango (talk) 19:43, 1 November 2009 (UTC)

See Astronaut#Training for NASAs requirements. Other space agencies will be similar. --Tango (talk) 19:45, 1 November 2009 (UTC)

Right, there are lots of different researchers in space, not just physicists, and definitely not just pilots... it is not the 1960s anymore. --Mr.98 (talk) 20:45, 1 November 2009 (UTC)

Inflammatory result of depolarization theory regarding migraines

That title could've been better. But! I've been reading up on your excellent migraine article, and it lists, among other things, depolarization and serotonin levels as resulting in pain. It is the first I am interested in, because browsing through depolarization and action potential, I am hard pressed to understand exactly what it is that causes an inflammatory agent to be released when a depression occurs. I am quite the noob on this field, and so I feel I may have missed something. As I have understood this matter, a depolarization essentially inhibits to a great extent the cells' ability to communicate, suffering from reduced or nonexistant permeability. Under any circumstance, your help is much appreciated! 91.149.2.165 (talk) 10:40, 1 November 2009 (UTC)

Studies in psychoneuroimmunology have shown that during depression proinflammatory neuropeptides (SP) and cytokines (e.g., IL 1 and IL 2) are released as a result of over activation of the sympathetic nervous system and the HPA axis->leading to acute phase response and to the release of Acute-phase proteins. This is only part of the phsyiological effects of different negative emotional situations.--Gilisa (talk) 11:46, 1 November 2009 (UTC)

I am terribly sorry for having used the word "depression", when I in fact meant cortical spreading depression! I understand your answer thus has less validity. :) 91.149.2.165 (talk) 12:19, 1 November 2009 (UTC)

Actually it does have connection after all as cortical spreading depression may lead to the release of SP, but I don't familiar with works on this mechanism and neuroimmunology is not my expertise. I addressed your question to Dr Dima, he may know the answer.--Gilisa (talk) 13:03, 1 November 2009 (UTC)

Absolutely marvellous! Thank you for taking your time on this issue, I certainly hope for a good answer =) 91.149.2.165 (talk) 13:54, 1 November 2009 (UTC)

You welcome! I'm hoping for a good answer myself.--Gilisa (talk) 14:24, 1 November 2009 (UTC)

I will start from the end. When membrane of a neuron is depolarized by injecting electric current into the neuron, such depolarization leads to increased spiking probability. However, membrane depolarization in general does not imply increased spiking (and membrane hyperpolarization in general does not imply depression). When membrane is depolarized due to change in ion concentrations in the cell and around it, or due to change in conductances of particular type(s) of ion channels, such depolarization may be associated with either increased or decreased spiking probability. There is no contradiction, therefore, between depolarization and depression in the cortical spreading depression in a migraine. That being said, I do not know what exact changes in channel conductances and in the ion balance occur in the neurons in the areas affected by the spreading depression. I never worked on migraine or anything closely related. What I do know is that the depolarization is thought to be not produced by serotonin directly. According to the theory I am somewhat familiar with, mutations in a certain subunit of the voltage-gated P/Q-type calcium channel, or possibly other "channelopathies" in the brain stem, result in the over-active vascular response to the increased activity in certain areas of the cortex (see e.g. this article). Change in blood supply affects the activity in the cortex, which affects the blood supply even more, closing the positive feedback loop. Serotonin, it seems, mostly acts on the blood vessels and not on the cortex neurons in this case. However, with serotonin you never know, as most of its effects are modulatory rather than direct; and I am certainly not a migraine expert. I hope this helps in any way. --Dr Dima (talk) 17:46, 3 November 2009 (UTC)

Thank you, Dr Dima, for your time and answer. =) I am most thankful. I will study the article, and hopefully learn even more! 77.18.72.142 (talk) 19:51, 4 November 2009 (UTC)

subsequent natural GMO

How likely or what is the probability that a GMO such as corn with a GM to produce an insecticide or a cow designed to give milk with antibodies could undergo subsequent natural GM from a virus or pollutants or electromagnetic radiation resulting in an increase in production of insecticide or antibody which might render the GM product harmful? Biggerbannana (talk) 11:29, 1 November 2009 (UTC)

About the same as ordinary corn or an ordinary cow. We can't predict anything else. Cuddlyable3 (talk) 12:30, 1 November 2009 (UTC)

Perhaps then it depends upon where something grows but I can't find a map anywhere of areas with high numbers of trees that have large cancerous type growths on their trunks although they appear to be in areas near where phosphorus was discovered and is mined in South Florida and in other areas most likely to have phosphorous deposits which has a lot of radioactivity. Biggerbannana (talk) 14:50, 1 November 2009 (UTC)

In "captivity", these products' reproductive cycles are fairly closely tracked - it's unlikely that anything untoward would happen. The issues arise if they escape into the wild. In that case, those transgenic genes would continue to work and to be selected for (or against) and be possible targets for mutation. However, if the genes don't confer any particular benefit to the organism in the wild (for example, a sheep that produces human insulin in her milk) - and since the organism has to expend energy to produce these extra things - the odds are good that they'd be selected out after enough generations. If they DO offer benefits (resistance to certain common insects) - then they might be strongly selected for - and spread out into the wild population. There is evidence that this has happened already with Starlink corn. However, evolution is only going to operate in ways that strictly benefit the organism - which means that there has to be a balance between the cost to the organism to produce whatever this effect is - and the benefits. The fact that wild versions of the organism didn't already evolve this kind of protection suggests that the cost may have been higher than the benefits - but it's really tough to know. Of course it's much less likely that it would be a virus, pollutants or radiation causing the gene to mutate (a relatively rare event) so much as it's likely that mixtures of the transgenic gene with other (relatively rare) genes already out there in the wild population would increase the effectiveness of the transgenic gene in some way (eg by feeding it's chemical pathway with more inputs). So the odds aren't zero that the release of transgenic organisms might cause gradual evolution of novel new features. SteveBaker (talk) 15:25, 1 November 2009 (UTC)

Sounds like what you are saying is that because the two conductor extension cord I found at a local South Korean flea market had blades made of pot metal and 26 gauge copper wires covered by thick insulation attached only by the pressure of the molded plug holding the blades and wires together is okay even though they violate the electrical standard because they will melt quickly and act like a fuse despite the unlikely possibility of not melting quickly and instead heating up slowly resulting in a fire. Biggerbannana (talk) 16:44, 1 November 2009 (UTC)

That is one of the worst rationalizations I've read here - to the point that it is very difficult to assume that you are actually asking a question and not just ranting about GM products based on little (or no) actual knowledge of GM. He stated that evolution works towards the benefit of the organism. If a genetic modification does not benefit the organism, it will not tend to spread. Try - though I know it is very difficult - to relate that to an organism, not an extension cord. -- kainaw™ 20:10, 1 November 2009 (UTC)

The reference being that anyone can produce inferior goods or follow an insufficient regimen to make money without dependence upon repeat buyers. Biggerbannana (talk) 04:37, 2 November 2009 (UTC)

(It's of note, of course, that "benefit of the organism" is not the same thing as "benefit to people." Mutations in viruses that are good for the organism are often quite bad for humans!) --Mr.98 (talk) 22:49, 1 November 2009 (UTC)

I will also add that although what SteveBaker says is correct, it's possible that increased production can be harmful to other creatures (such as humans who eat the cow or corn), although usually indirectly e.g. massively increased production of antibiotics creates promotes resistance in those infectious agents, thereby making the disease harder to cure in humans. ~ Amory (u • t • c) 21:19, 1 November 2009 (UTC)

It may be worth remembering that many plants that we eat already have a number of compounds which are clearly harmful to humans in sufficient quantities. E.g. solanine in potatoes. A far greater concern then any potential (direct) harm to humans is the ecological effects of transgenes. In particular, if the transgene is beneficial to the plant but harmful to something else (e.g. insects or other plants) if the transgene spreads as SB mentioned and spreads widely enough this may have a negative effect on the ecological balance. A key issue is whether and what other wild species the transgene can spread to, as most plants cultivated for food don't survive particularly well in the wild because they're so screwed up, the addition of whatever transgenes is probably not enough to make them into weeds. Note in case it isn't obvious, this doesn't usually doesn't require any mutation. A terminator gene would hopefully nearly eliminate the spread. All this is something that has received plenty of research, so you could easily find many references if you are interested Nil Einne (talk) 22:55, 1 November 2009 (UTC)

Lots of things may have benefited the dinosaurs to our detriment but praise God for the asteroid. Wild or captive anything which might give our molecular adversaries a distinct and overpowering advantage in the long term is still not a good thing even though not present in the short term. Scientists pride themselves on thinking of every possible scenario and that is where the problem lies. Biggerbannana (talk) 04:45, 2 November 2009 (UTC)

I'm not sure "Scientists pride themselves on thinking of every possible scenario" is really the point. I mean, what? Imagine Reason (talk) 19:15, 2 November 2009 (UTC)

The problem comes when scientists fail to live up to their expectations and a few unwelcome scenarios slip passed. In such cases we see reactions from others and unfortunately as a matter of pride a complete effort at dismissal. The Titanic is unsinkable. The seals on the Space Shuttle boosters work great. The American Colonies support Britain. I've probably forgotten a few other better examples. Biggerbannana (talk) 21:06, 2 November 2009 (UTC)

Humans did not coexist with dinosaurs. Please do not use this space to promote a God of some belief system even if you think He willed an asteroid to impact Earth. The Titanic sank because of failed seamanship and inadequate engineering. The seals on the Space Shuttle failed because of failed corporate engineering. The American revolution arose because of failed foreign policy by Britain. No scientists were implicated, least of all any GM biologists who would be relevant to the OP meaning the Original Post not the subsequent debating by the same user. Cuddlyable3 (talk) 22:53, 2 November 2009 (UTC)

I think BiggerBannana is referring to the notion of hubris. That GMO proponents seem to operate on the premise that we understand all the variables and modes of interaction, and that even if we did not, the consequences would be manageable. Further, I believe that BB's reference to God is an allusion to scientism. Unomi (talk) 00:05, 7 November 2009 (UTC)

PCR for diagnosis of genital warts

Hi the wikipedia article on genital warts says that less than 1% of people infected with the HPV virus develop visible warts. I'm doing some research into how genital warts are diagnosed in the UK. The only diagnostic tests mentioned on the NHS website are: warts being examined by a doctor and colposcopy. However, if the wikipedia article is right, then 99% of people with genital warts will not be diagnosed by these methods! I've also read that PCR can be used to diagnose genital warts, this could be used to diagnose the vast majority of people who are asymptomatic. My question is does the NHS provide PCR tests for genital warts? Thanks to anyone who can help! RichYPE (talk) 14:26, 1 November 2009 (UTC)

If you are unable to find this information online, you could try calling the NHS' telephone health information line, NHS Direct. TenOfAllTrades(talk) 15:00, 1 November 2009 (UTC)

This question verges on the strict "no medical questions" rule, so I'll answer carefully. Useful search terms would be "genito urinary". The NHS wesites I've seen say that they diagnose by looking, and that only visible warts can be treated. Here's some websites: WARNING: REVOLTING IMAGES http://www.chestersexualhealth.co.uk/genitalwarts.htm - and another link that talks about visual diagnosis http://www.nhsdirect.wales.nhs.uk/encyclopaedia/g/article/genitalwarts/. Remember Civility (talk) 15:58, 1 November 2009 (UTC)

It's a prohibition again medical advice, not medical questions. The OP is clearly not asking for medical advice. --Mr.98 (talk) 16:24, 1 November 2009 (UTC)

thanks for the clarification. I should have been more precise: "Some may think my answer verges on the strict no medical advice rules, but don't worry, I'm being careful". Is that better? Remember Civility (talk) 19:23, 2 November 2009 (UTC)

Also deleting a warning against a known hazard as if it were medical advice is extremely careless. Maybe even culpable. Biggerbannana (talk) 18:59, 1 November 2009 (UTC)

Again, nobody is talking about personal or at-home treatments. (In any case, the treatment plan you mentioned would only be prescribed by a doctor, and would carry copious instructions and warnings and etc. on it anyway.) --Mr.98 (talk) 00:41, 2 November 2009 (UTC)

My understanding is that acetic acid is not prescribed to the patient by the doctor but is used much as a laboratory stain to reveal altered tissue and therefore no warning is called for between doctor and patient but rather between the pharmaceutical company and the doctor. Common sources of acetic acid (vinegar) do not have warnings in regard to its use as a stain or as a cure for wards by its constant or prolonged application to a wart. Ignoring or thwarting the opportunity to provide such warning here does not accomplish the Wikipedia ban of giving medical advice but rather opens the Wikipedia to a potential charge of culpable negligence. Warnings are not medical advice but the responsibility of anyone with knowledge of the danger to convey that knowledge to others. Biggerbannana (talk) 15:47, 2 November 2009 (UTC)

Nobody is talking about treatments, and I've never heard of anybody trying to use vinegar at home (I don't really think you know what you are talking about, regarding what doctors prescribe). You are being ridiculous regarding "potential charge of culpable negligence", because Wikipedia is not recommending anyone do anything, much less anything negligent. You might as well argue that Wikipedia is negligent because every time somebody asks about electricity we don't warn people about the risk of electric shock. If you really have a problem with the medical policy here, just take it to the talk page. You are creating an issue here out of nothing and being silly. --Mr.98 (talk) 23:27, 2 November 2009 (UTC)

I support Mr.98 here. This section is for responses to the OP's question within Ref. Desk policies, not for inventing pseudo-legal accusations. Cuddlyable3 (talk) 11:30, 3 November 2009 (UTC)

chemical induced orgasam

I've heard that electricity has been used to stimulate the genital region but I do not know if it is to the point of orgasm. Is there chemical which can do this? Biggerbannana (talk) 18:55, 1 November 2009 (UTC)

SSRI usage can sometimes result in spontaneous orgasms.[14] Red Act (talk) 19:22, 1 November 2009 (UTC)

Conversely, SSRIs can also prevent orgasm. Mitch Ames (talk) 23:43, 1 November 2009 (UTC)

Clomipramine, which is a TCA, can also cause spontaneous orgasms. Interestingly, these antidepressant-caused orgasms are sometimes triggered by sneezing.[15] Red Act (talk) 20:12, 1 November 2009 (UTC)

Effect of optimism on health

I've often heard it claimed as folk wisdom that "positive thinking has been proven to have a positive effect on recovering from illness" or something similar. My understanding is this is likely based off a few hastily done studies in the seventies which probably found nothing more than the obvious link of heavy stress and it wearing out the body. Additionally, further studies that were done extensively failed to show a link. Do we have an article on this, or anything to back it up? I read this in a magazine, and I would like to probe more in depth; my scientific mind finds it very unlikely that the new age baloney about just having a positive attitude vs. a resigned attitude will have any effect on your illness; short of, of course, extreme stress. Magog the Ogre (talk) 20:16, 1 November 2009 (UTC)

I don't have a lot of knowledge of this topic but I think there is some pretty solid evidence, see PMID 17709956 for example. For your scientific mind, one basic mechanism is that a variety of negative emotions increase the activity of the HPA axis, which leads to increased cortisol secretion, and cortisol has a variety of effects that tend to impair responses to illness, including direct suppression of immune responses. There are currently several whole journals devoted to studying the interactions between the nervous system and the immune system. Looie496 (talk) 21:04, 1 November 2009 (UTC)

I believe the entire institution of placebos may undermine your pessimistic approach towards optomism. Not to mention psychological disorders, in which the mind is essentially the object of the ailment. :) DRosenbach ^{(Talk | Contribs)} 21:06, 1 November 2009 (UTC)

Actually it was found that people who can find attributions for "why me" or to give meaning for live threatening diseases thay were dealing with are more adaptive and have higher survival rates.--Gilisa (talk) 21:40, 1 November 2009 (UTC)

To DRosenbach: the placebo has less to do with actually getting better than how one reports his/her symptoms? I.e., did you feel noticeably better when taking this/that drug? To Gilisa: do you have any sourcing? It's precisely this type of thinking for which the author of the magazine article I was reading was critical. Magog the Ogre (talk) 00:02, 2 November 2009 (UTC)

Did you read the linked article on placebos? The changes are a lot more complicated then simply different reports of symptoms and the article is resonably detailed and sufficiently referenced Nil Einne (talk) 00:32, 2 November 2009 (UTC)

Look at "The Search for Meaning Following a Storke" by S.Z. Thompson (1991) for a review. It's a bit old one but still invariably cited even in recent articles on similar issues. The effects of negative mood on one's health are obvious and were demonstrated using the most rigorous experimental methods and proven to the molecular level. It's a bit harder to make molecular studies on happiness, but at the least-being happy means not being depressed.--Gilisa (talk) 12:52, 2 November 2009 (UTC)

I speculate that optimism and good health could both be the result of having sufficient levels of Vitamin D in the body. People in northern latitudes are thought to be deficient during the winter (see Scientific American article from November 2008), and personally I always find the darkening nights of autumn a depressing time, for example. I have seen a scientific paper that speculated that the health benefits of fish could be as a result of their Vitamin D content - do not know if there is any triuth in that. Note that excessive consumption of Vitamin D is harmful and dangerous. 78.146.167.26 (talk) 15:06, 2 November 2009 (UTC)

How much land is needed to support people?

Hi,

For one average person, or family, in 'the west', lets say Western Europe, how much land in terms of agricultural area is on average needed to support them in terms of food. I know there is no specific amount and the numbers vary widely depending on the habits of countries, eg fish/carbohydrate based diet, and depending on the quality of land in said place but there must be some sort of figure saying something like 'on average one person consumes 1/4 acre of wheat per year' or something like that. Also any figures for other natural resources eg timber, water etc would be useful. Thanks, --86.136.37.191 (talk) 21:47, 1 November 2009 (UTC)

Someone asked a similar question here. People there gave a wide range of answers, I think it really depends on what kind of crop and how much diversity the people eat. Potatoes are famously compact, while any kind of meat is going to require much more overall. Someone at that link said .5Ha per person for a typical Western diet. I would also think it depends heavily on the quality of the land, specifically whether it gets enough water. Sorry, I guess this turned out to be a pretty waffling response ;) TastyCakes (talk) 21:55, 1 November 2009 (UTC)

Oh, also I would imagine if you're in a year round warm climate that gets lots of rain, like much of the equator, each acre is going to be more productive overall and the land needed per capita is going to get smaller. This list gives an idea of this. In Bangladesh, there are apparently 1,946 people per square km of arable land, which is just over .05 hectares per person, and I doubt they are a big net importer of food (although maybe I'm wrong on that). TastyCakes (talk) 22:27, 1 November 2009 (UTC)

Oh, and this page gives some crop yields in tons per hectare. You have to click on the "Table" icons on the left to see them. TastyCakes (talk) 22:30, 1 November 2009 (UTC)

The Tables are likely in tonnes per hectare (t/ha) and not tons per hectare.

Yes, sorry that is likely correct. TastyCakes (talk) 04:04, 2 November 2009 (UTC)

Does phosphorylation occur only with OH / COOH groups?

In order to be phosphorylated, you kind of need to have slight nucleophilicity to begin with right? You can't phosphorylate something if it doesn't have a nucleophilic -OH group to begin with? (The -OH group can be part of a pi system like a carboxylic acid.) John Riemann Soong (talk) 23:08, 1 November 2009 (UTC)

November 2

Hammerhead Sharks

In what part of the world are hammerhead sharks usually found? The article on them didn't give any specific locations.99.251.239.89 (talk) 00:25, 2 November 2009 (UTC)

Hammerhead is a genus name and is pretty broad. Click on the individual species links (e.g. Scalloped hammerhead, Great hammerhead) and you'll see little maps. --Mr.98 (talk) 00:45, 2 November 2009 (UTC)

(edit conflict) That would depend on which shark you wanted. ~ Amory (u • t • c) 00:48, 2 November 2009 (UTC)

Cute. DRosenbach ^{(Talk | Contribs)} 15:52, 2 November 2009 (UTC)

h1n1 vaccine

hey is there blood in the h1n1 vaccine? i cant find any info on whats in it.--Least0190 (talk) 00:28, 2 November 2009 (UTC)

I don't think there is blood (human or otherwise) in any modern vaccine. --Mr.98 (talk) 00:35, 2 November 2009 (UTC)

However, there are chicken egg proteins in it, so if you have any allergies to chicken eggs, you may not be able to take that vaccine. See also 2009 flu pandemic vaccine for the H1N1 (swine flu) vaccine, and Influenza vaccine for flu vaccines in general. --Jayron32 00:40, 2 November 2009 (UTC)

(edit conflict) There most definitely is not. The only people who are injected with any sort of blood are heroine addicts. ~ Amory (u • t • c) 00:40, 2 November 2009 (UTC)

For proof (sort of) you can read Hemagglutinin (influenza). Essentially, flu surface proteins cause blood to clump in vitro, which would make for a very ineffective vaccine. ~ Amory (u • t • c) 00:43, 2 November 2009 (UTC)

{Sidetrack: While I am personally addicted to heroes, I am doubtful about Amory's claim above that heroin addicts are "injected with blood". There may be blood in dirty needles, but there is, as far as I know, no intent to inject blood. ( Blood dopers may inject blood, but that has nothing to do with heroin.) Is there some treatment technique that involves blood injections for addicts?} Bielle (talk) 00:56, 2 November 2009 (UTC)

Not a treatment by any means - Heroin users who want the hit to hit faster and the high to be higher have been known to stick the needle in their arm, draw a little bit of blood up into the syringe, then inject the mixture back in. It's a great way to OD or get bubbles into your bloodstream, and a really, really, really stupid thing to do, but then so is doing heroin. Trainspotting features this technique, iirc. ~ Amory (u • t • c) 01:00, 2 November 2009 (UTC)

I am now better educated. Thank you, Amory. Bielle (talk) 01:04, 2 November 2009 (UTC)

Honestly this doesn't make sense to me. How would this get the heroin to your brain any faster? I had a vague notion that the idea was precisely to prevent bubbles — once your blood was up in the syringe, you knew there was no air in the needle. I don't know whether that makes sense either, but it's more plausible than that it makes you high faster. --Trovatore (talk) 01:43, 2 November 2009 (UTC)

Likely there are 2 good reasons for drawing a little blood, 1. you are sure that you are actually in a vein. 2. you ensure that there isn't too much heroin wasted residually in the needle. Unomi (talk) 01:53, 2 November 2009 (UTC)

Ah right, the vein thing, I think that was it, not the bubbles. --Trovatore (talk) 04:00, 2 November 2009 (UTC)

Well, for one, some people think that mixing powder with water weakens it, so they just put the powder in the syringe, then use the blood to put it in solution. ~ Amory (u • t • c) 06:20, 2 November 2009 (UTC)

Well, there's one pretty blatant error above -- people who get a blood transfusion are certainly injected with blood, obviously. Looie496 (talk) 02:42, 2 November 2009 (UTC)

I left an obnoxious semantic loophole there for myself - transfusions aren't so much injected, per se, as they are dripped. ~ Amory (u • t • c) 06:13, 2 November 2009 (UTC)

ok thanks guys its just that i read that it has pig and horse blood in it, i dont want animals blood in me.--Least0190 (talk) 03:27, 2 November 2009 (UTC)

If you want it, here's a link. You can read through the full contents of each vaccine, and see that none of them contain anything like that. The closest you get, as Jayron said, is the possibility of less than one millionth of a gram of egg proteins. ~ Amory (u • t • c) 06:20, 2 November 2009 (UTC)

May I suggest for you Carl Sagan's The Demon-Haunted World? Imagine Reason (talk) 19:13, 2 November 2009 (UTC)

Is it possible for energy/ information to travel faster than speed of light in the following case

Let we have a straight pipe AB long but greater than 300,000 km in the free space or vacuum. The pipe is full of small balls of perfect shapes from point A to B and each ball is connected to each other just like two circles at their common tangent point. Assume there is no friction between the pipe and balls. For simplicity we can also ignore the pipe.

Would the last ball at point B be move out if we add a ball to point A of the pipe in less than a second, if not why?

I know nothing can travel greater than speed of light but I'm just asking if it might possible. Thanks 68.147.38.24 (talk) 01:34, 2 November 2009 (UTC) khattak

Nothing can be perfectly rigid. The balls are made up of atoms. When you push on the first ball, what happens? Its atoms get pushed closer together. They don't want to be closer together, so they start pushing on other atoms behind them, which move farther away. This generates a compression wave down the pipe, which moves quite fast, but slower than light. (It probably moves at about the speed of sound in whatever the balls are made of.) --Trovatore (talk) 01:38, 2 November 2009 (UTC)

Thank you for your swift reply but sorry to ask you again. Would your answer be the same if two persons commune each other by pushing the same whole pipe or rod in dark space against one another? Because there is diference between the pushing speed of atoms and the pushing speed of the whole pipe/ rod 68.147.38.24 (talk) 03:42, 2 November 2009 (UTC)khattak

"The whole pipe/rod" is an object composed of atoms. It is no more solid and no more rigid than its full packing of balls. DMacks (talk) 03:48, 2 November 2009 (UTC)

Trovatore and DMacks are correct. See "Faster-than-light#FTL_phenomena" for some interesting findings. Axl ¤ [Talk] 07:10, 2 November 2009 (UTC)

Supposing the rod was made of quark matter?80.2.195.180 (talk) 12:30, 2 November 2009 (UTC)Trevor Loughlin

Ho hum, I asked this question a while back - revisiting the archive, I see I forgot to respond, so here's a belated thanks to everyone who answered me. Here is that discussion. Vimescarrot (talk) 13:38, 2 November 2009 (UTC)

This question is asked so often that it has made me wonder if we have a template for the constant answer that keeps getting rehashed over and over. -- kainaw™ 15:09, 2 November 2009 (UTC)

Hmmm... I just thought that if I have time today, I will trek through the archives and get a list of links to the previous questions. There should be at least 100 of them. Then I can make a template that says: "Your question has been asked and answered here and here and here and here and here and here and here...." -- kainaw™ 15:10, 2 November 2009 (UTC)

Hmm... seems like more work than just answering it again, in most cases (or, putting it another way—it is probably easier for four people to recapitulate parts of an answer than it is for one person to look up all of the previous answers. Also more fun, for the four people). This one is common enough in general that we could have just provided Google links—[16]. --Mr.98 (talk) 16:10, 2 November 2009 (UTC)

That information cannot travel faster than the speed of light (locally, at least) is a fundamental principle of special and general relativity. Those theories have been very successful at making predictions we have experimentally verified, so we assume that principle is correct. That means that there is a fundamental limit on the rigidity of any object, whatever its composition, since it the speed of sound in it (which is what we are talking about, really) must be slower than the speed of light. --Tango (talk) 18:34, 2 November 2009 (UTC)

Short answer: in order to change what is happening, you need to apply a force. Either you force something directly, or apply a force to something which applies a force to something else ... We only have four forces - electromagnetism, gravity, strong, and weak, and all four are transmitted (over long distances) at the speed of light. No force travels faster than light, so your effect can't be transmitted faster than light. -- 128.104.112.149 (talk) 22:15, 2 November 2009 (UTC)

What about Quantum entanglement? From the dictionary: a quantum mechanical phenomenon in which the quantum states of two or more objects have at all times to be described with reference to each other, each instantaneously tracking changes to the other, however large the spatial separation of the objects. Instantaneously, no matter what the distance. That's faster than the speed of light. 20.137.18.50 (talk) 17:51, 3 November 2009 (UTC)

It's only in a very limited way that quantum entanglement can violate locality. Regardless of quantum entanglement, information can't travel faster than the speed of light, which applies in the case of pushing a long rod. See no-communication theorem. Red Act (talk) 18:42, 3 November 2009 (UTC)

In short - the quantum states being transmitted are random, so you can't use them to communicate anything other than random values. I did see a proposal that they could be used to communicate a random key for encryption. The encrypted information would then be transmitted by conventional means. --Tango (talk) 18:47, 3 November 2009 (UTC)

I got rid of the wrong definition at Wiktionary. The original entry, created on August 10, 2005, was okay, if not very edifying. Five days later it was replaced with the incorrect one, which survived for more than four years. Sigh. -- BenRG (talk) 19:49, 3 November 2009 (UTC)

hox and homeotic transformation

"I have a question/challenge on the homeotic gene page. Are HOX actually homeotic? They definitely are in their ability to regulate A/P development (with anteriorization if a paralogous cluster is knocked out), but there are not homeotic transformations of the limbs in knockouts (HOX 10 and HOX 11 Genes are Required to Globally Pattern the Mammalian Skeleton, Capecchi, et al., 2003, Science Vol 301, p363) From this article, while there are gross limb defects, there is not the reassignment of stylopod to zeugopod, or anything along those lines, making me think that these genes are not completely homeotic in nature. Thoughts? Thanks for maintaining this extremely important page." —Preceding unsigned comment added by Terragamo (talk • contribs) 05:06, 2 November 2009 (UTC)

I believe the HOX genes are unusual in that respect due to the nature of their distinction in limb development. The differential expression of the HOX genes is established during the limb bud stage, when the future limb is at only a small fraction of its final length, barely extended from the imaginal disc. It'll be a day before I can get back to my old developmental textbook, though, so I should note that that's simply my idea. Someguy1221 (talk) 05:12, 2 November 2009 (UTC)

carbon monoxide

Plants metabolize carbon dioxide. What about carbon monoxide? 71.100.8.110 (talk) 06:20, 2 November 2009 (UTC)

They're capable of metabolizing carbon monoxide, but the experiments that showed this exposed the plants to carbon dioxide free atmosphere, so I'm not sure how physiologically significant the effect is. One paper describing this: [17] Someguy1221 (talk) 06:26, 2 November 2009 (UTC)

What happens if a non-depressed person takes anti-depressants?

Not a request for medical advice as I'm just curious about what would happen. Assuming they took them regularly for some time. Would they feel happier, drunk, manic, lose their rational judgment, what? It seems like a scenario for a dystopian science-fiction novel. 78.146.167.26 (talk) 14:58, 2 November 2009 (UTC)

The answer is going to depend on which specific anit-depressant drug is taken. Googlemeister (talk) 15:39, 2 November 2009 (UTC)

And the dose. --Mr.98 (talk) 16:13, 2 November 2009 (UTC)

Don't those drugs sometimes have nasty side-effects? RJFJR (talk) 15:47, 2 November 2009 (UTC)

Drug abuse and antidepressant might be a good starting point... TastyCakes (talk) 16:25, 2 November 2009 (UTC)

Terrible withdrawals as well if you forget a dose. Readro (talk) 16:56, 2 November 2009 (UTC)

Not really. They take several days to begin to take effect. Withdrawal happens after a week or so.--Drknkn (talk) 17:30, 2 November 2009 (UTC)

That really depends on the drug (and its half-life). Effexor can cause withdrawal with a single missed dose, the same day you missed it. -- Aeluwas (talk) 18:38, 2 November 2009 (UTC)

I was speaking from personal experience, and you managed to guess my brand of pills in one! Congratulations :) Readro (talk) 20:53, 2 November 2009 (UTC)

I didn't know about that drug. I've used Paxil, Prozac, and Zoloft. They work slowly.--Drknkn (talk) 21:15, 2 November 2009 (UTC)

The vast majority of real-world side effects are mental. Lethargy (laziness), and apathy are common, especially with Zoloft. Anti-depressants do more to curb caring in general than depression. So, you don't feel over-joyed or anything. You'd need a stimulant (like, say, ritalin) for that. If you're already happy, and you take a stimulant, then you'd feel ecstatic. But if you're anxious and you take a stimulant, then the results could be catastrophic.--Drknkn (talk) 17:29, 2 November 2009 (UTC)

. Comet Tuttle (talk) 18:04, 2 November 2009 (UTC)

This article suggests that some non-depressed people have become habitual users of anti-depressants for "lifestyle" reasons, perhaps after first being prescribed them for reasons other than depression. The user cited in the article does indeed claim that his daily SSRI makes him feel happier, although it is made clear that the effects of using these drugs in this way are unknown and potentially dangerous. Karenjc 18:40, 2 November 2009 (UTC)

I don't think it's that simple. Depressants like alcohol, for unknown reasons, make people feel good, while stimulants often dampen their enthusiasm. Imagine Reason (talk) 19:10, 2 November 2009 (UTC)

Right. I guess it depends on your personality. I've used Paxil, Prozac, and Zoloft over the years. They all make me lethargic and apathetic. Alcohol makes me depressed, but other people get happy when they're drunk, so YMMV.--Drknkn (talk) 21:15, 2 November 2009 (UTC)

There are different types of anti-depressants. "Tri-cyclics", "MAOI", "SSRI", and then a bunch which are a bit like SSRIs but have different acronyms, such as NASAs, etc. Ann and Bob might have very different experiences even of the same dose of the same medication. There's something called "seretonin syndrome" which can affect people who overdose on soem types of anti-depressant meds. One way to answer the question would be to look at the side-effects of the medications, and the frequency of those side effects, to see what might happen. Don't forget the important Placebo Effect either. Remember Civility (talk) 19:33, 2 November 2009 (UTC)

Some antidepressants are routinely prescribed for their side-effects, not their anti-depressant effect. See Amitryptiline. I've just come off this drug after 15 years on it for nerve pain: apparently it is the treatment of choice for such pain. I didn't notice a particular anti-depressant effect while I was on it. --TammyMoet (talk) 20:33, 2 November 2009 (UTC)

The best conversations of this variety I've had focus on how little one might notice unless in a particular or exceptional situation, or unless they already knew what to look for. Regardless of type taken and mental state before starting, some things that are pretty generic side effects anyone could get could start to appear in just a few days if there's even a minor adjustment in what was already a good chemical balance. Things like... Misinterpretation of intoxication level , headache, light sleeping problems/problems falling asleep, loss of sex drive, difficulty concentrating, unusual fatigue/grogginess are universal. Those are all relatively minor and are pretty easily shrugged off by long-term patients but could feel quite amplified and frightening if you body doesn't quite know what to do with it. There aren't any specific "automatics" as theoretical benefits, and even if there were I can't see why someone would want to put up with the negatives. My biggest concern for someone in "normal" mental health using would be the risk of sudden, um... death? Without a doctor to look over your medical history and put you on a small trial dose of something to make sure you're not allergic in any way, odds are higher of running into some terribly bad side effects like an irregular heartbeat, confusion and blackouts (re: driving), general paranoia, insomnia. Even if none of that ever happened, you'd continuously be at the risk of day-to-day stresses or normal medications throwing things awry; Extreme caffeine consumption, certain cold or allergy medications, prescription painkillers or just extreme fatigue might trigger an undesirable reaction either 'up' or 'down'. This why there will never be any official studies-- it's just too damn unethical to ever have someone take medications like this "just to see". I'd thwap anyone who decided to so something this stupid. ♪ daTheisen(talk) 09:38, 4 November 2009 (UTC)

the form of energy as matter

Harmonic analysis/synthesis reveals that a combination of sinusoidal frequencies can generate an approximate square wave of any amplitude with a virtually infinite wavelength or zero frequency (assuming that in the case of the expression of energy that the reason absolute zero can not be obtained is the same reason absolute zero frequency can not be obtained). Is it possible that this state of combined frequencies is the state of energy we call energy or matter in the form of a particle? Biggerbannana (talk) 15:25, 2 November 2009 (UTC)

I'm not really sure what you mean. What are you measuring the frequency of exactly?

The wave function of a particle has a non-zero frequency. See matter wave. Rckrone (talk) 17:23, 2 November 2009 (UTC)

The idea I am referring to is that of matter or energy being created in a star say by fusion when two atoms of hydrogen becomes one atom of helium. While hydrogen and helium are both matter the energy difference is not expressed in the form of matter but in the form of electromagnetic radiation. The amount of this electromagnetic radiation is known. However, the radiation contains both light and heat and x-rays and Gamma rays and more. However, if you only measure the visible light energy then you come up short and the same for all of the other wavelengths as well but not if you add them all together. When you do add them all together and plot a graph you should get approximately a square wave which itself may have a wavelength near one half the half life of Helium. What I am asking is has anyone else explored this idea and if so have they written a paper? Biggerbannana (talk) 20:52, 2 November 2009 (UTC)

Animation of the additive synthesis of a square wave with an increasing number of harmonics

A square wave is the sum of an infinite series of sinusoidal waves. Conversely a square wave can be generated by adding together the same series of sinusoidal waves. The frequency of the square wave is that of the lowest frequency sinusoidal wave, so this is not a way to generate a lower frequency wave than one already has. The amplitude of the square wave is less than the amplitude of the lowest frequency sinusoidal wave, shown by the animation. Cuddlyable3 (talk) 22:25, 2 November 2009 (UTC)

What would say is the lowest electromagnetic frequency produced by the fusion reaction and its amplitude? For that matter how about the amplitude of each frequency produced? 71.100.8.110 (talk) 02:12, 3 November 2009 (UTC)

A single fusion reaction doesn't create a wide spectrum of EM radiation. The energy released is in the form of just one or a few high energy photons and some kinetic energy. Rckrone (talk) 00:09, 3 November 2009 (UTC)

Yes and the amplitude and frequency of each...? Have any been measured and added? Biggerbannana (talk) 02:27, 3 November 2009 (UTC)

They certainly have been measured, but it depends on what reaction it is and on your reference frame. The point I was making is that the Fourier series of a square wave has countably infinite non-zero terms. You can't build it out of 1 or 3 or even 100 frequencies. Rckrone (talk) 06:09, 3 November 2009 (UTC)

I disagree. Although not a perfect square wave only a few frequencies are necessary to produce a reasonable one with less that maximum amplitude but sufficient duration to trigger a programmable voltage sensor for instance. Biggerbannana (talk) 13:26, 3 November 2009 (UTC)

But they don't make anything that looks like that. If you have a reaction that sends off one gamma ray, there's no way to argue that's something like a square wave, and the frequency is somewhere on the order of 10¹⁹ Hz, which is a bit off from the theorized half life of a proton which would be less than 10^-41 Hz. Rckrone (talk) 17:51, 3 November 2009 (UTC)

The fact that the sinusoidal components of a square wave have specific relative amplitudes and phases seems to be overlooked here.Cuddlyable3 (talk) 08:04, 4 November 2009 (UTC)

Also not sure how you would measure the amplitudes of each of these components. The Fourier coefficients have to go to zero as the frequency go to infinity, but the energy of a photon grows. Rckrone (talk) 06:45, 3 November 2009 (UTC)

BTW -thanks for whomever provided the graph... 71.100.8.110 (talk) 02:14, 3 November 2009 (UTC)

YW. User Kief on Commons made the animation and I posted it. Cuddlyable3 (talk) 11:16, 3 November 2009 (UTC)

Much thanks or hugs and kisses if you are female. ;) Biggerbannana (talk) 13:28, 3 November 2009 (UTC)

That is the kind of male chauvinist sexist discrimination that belongs to another less enlightened age. Keep your banana to yourself.Cuddlyable3 (talk) 08:00, 4 November 2009 (UTC)

Definition of species

The most common definition of species that I've seen is that a species is a group of organisms that can breed with one another to produce fertile offspring. How are species defined for bacteria and other organisms that reproduce asexually? ----J4\/4 <talk> 18:15, 2 November 2009 (UTC)

Species#Definitions of species discusses this issue. Basically, the answer is that there is no good answer. --Tango (talk) 18:30, 2 November 2009 (UTC)

It's a controversial area. See "Species" and "Species problem". There are many species that have been renamed/reclassified: Helicobacter pylori (previously Campylobacter/campylobacter-like organism), Moraxella catarrhalis (previously Branhamella), Pneumocystis jiroveci (previously Pneumocystis carinii), etc.. Axl ¤ [Talk] 18:35, 2 November 2009 (UTC)

Centrifugal force in Earth's orbit

Are there any observable effects of the centrifugal force experienced on the Earth as a result of its orbit around the sun? (Not the centrifugal force resulting from the spinning of the earth on its axis.) For instance, the weight of an object should be slightly greater when it is between the earth and the sun (i.e. daytime) versus when the earth is between it and the sun (i.e. nighttime). I assume that this weight discrepancy would be too small to measure, but is there any such effect that can be measured? Or perhaps I'm thinking wrong about the whole thing? Thanks- Staecker (talk) 19:56, 2 November 2009 (UTC)

There is a tidal force on the Earth due to the sun that causes a noticeable effect. The tidal force on the Earth due to the moon is about twice as big, though. The tidal forces on the Earth from the moon and to a lesser extent the sun are what causes tides. Red Act (talk) 20:18, 2 November 2009 (UTC)

Indeed. That tidal force is what the OP is describing - the centrifugal force is equal to the gravitational force (in an inertial frame of reference the gravitational force is a centripetal force and there is no centrifugal force, but if the Earth's frame there is). The difference between the gravitational force between two points on the Earth is called a tidal force. --Tango (talk) 20:27, 2 November 2009 (UTC)

I'd just add that sometimes the Sun tide and Moon tide reinforce one another (the so-called spring tide), and sometimes partially cancel out (neap tide). This effect has presumably been observed for as long as Man has gone to sea, so yes, the effect is very observable, even if it took a while to figure out the reason. --Trovatore (talk) 20:29, 2 November 2009 (UTC)

• Tides have nothing to do with centrifugal force. Tides are due to gravity gradient, i.e. the fact that gravity diminishes with distance. Centrifugal force is due to being in a rotating frame of reference, i.e. in orbit. If the Earth was falling directly into the Sun instead of orbiting, there would by no centrifugal force due to its orbit, but there would still be a tide. Conversely, if the Earth was in a circular orbit but gravity was constant regardless of distance instead of diminishing as 1/r², there would be centrifugal force but no tides. --Anonymous, 06:50 UTC, November 3, 2009.

No, that's not so. The centrifugal force is larger on the midnight side than on the noon side. That still gives you tides. --Trovatore (talk) 06:53, 3 November 2009 (UTC)

Okay, that's a force gradient effect, but it's not a gravitational force gradient effect, therefore not a tide. --Anon, 22:49 UTC, November 3, 2009.

Well, it'll make the oceans swell up, so whatever you wanna call it, I guess. From the point of view of Mach's principle it should be the same.

A back-of-the-eyelids calculation last night while I was driving home suggests that the centrifugal force gradient should be responsible for one third of the observed tidal effect, not considering the Earth's rotation, which is an approximation I don't know whether you can make or not. Wouldn't stake my life on that being right, but it made sense while driving, anyway. --Trovatore (talk) 23:00, 3 November 2009 (UTC)

It must be 100% of it, otherwise where does the rest come from in that rotating reference frame? There is no gravitational force in that frame. Wait, that's not true. There is no resultant force in that frame. The centrifugal force must therefore equal the gravitational force, so presumably they each account for half the tides. --Tango (talk) 23:09, 3 November 2009 (UTC)

Centrifugal force is the same as centripetal force, just in a different frame of reference (and in the opposite direction). With constant gravity you would have centrifugal force because you have centripetal force (the gravity). The centripetal force would be constant, therefore the centrifugal force would the constant, therefore there would be no force gradient effects from either force. You can only have tides due to varying centrifugal force if you have a varying centripetal force and it is distinguished from tides only by the frame of reference, so they are as equivalent as gravity and acceleration. You can consider a radial free-fall situation in a rotating reference frame and the centrifugal force will still be there, so if you really wanted to I expect you could reformulate the tides in that situation in terms of a varying centrifugal force (I haven't actually tried, though). --Tango (talk) 23:09, 3 November 2009 (UTC)

No, there is no centrifugal force in this problem. I agree with Anonymous, tidal force has nothing to do with centrifugal force. A centrifugal force in this problem, if one existed, would tend to make the tides higher on the midnight side of the Earth than on the noon side of the Earth. But in reality, the tidal force raises the tides on the noon side of the Earth as much as on the midnight side of the Earth. Red Act (talk) 04:03, 4 November 2009 (UTC)

To first order, the centrifugal-force gradient also raises the tide the same amount on both sides. The thing to keep in mind is that the two forces balance at the Earth's center. If the gravitational force were of constant magnitude, but centrifugal force behaved as it actually does, then that would still be true for a circular orbit (I'm not sure if the orbit would still be stable, but that's a separate question).

So in this alternative reality with the constant gravity, we have that a piece of water in the noonday sun is subjected to the same gravitational force (from the Sun) as an equally massive piece singing Round Midnight. However the centripetal acceleration in daylight is smaller than that at the center of the Earth, which in turn is smaller by the same amount than that of the water gazing into the starry deep. --Trovatore (talk) 04:21, 4 November 2009 (UTC)

(Oh, to clarify: This is still ignoring the Earth's rotation. Imagine for the moment that the Earth always keeps the same face to the Sun, just to simplify things.) --Trovatore (talk) 04:24, 4 November 2009 (UTC)

The Effective potential is a way to rewrite the mechanical equations of motion to make it appear that earth's orbit is due to an "effective" force (centrifugal force) - but all that is really happening is that energy and momentum are being conserved. You can interpret the orbit as a "measurable effect" of centrifugal force in this treatment - but you should be aware of the assumptions made by such a formulation. Our effective potential article has a good overview of this topic. Nimur (talk) 20:33, 2 November 2009 (UTC)

The centrifugal force you're thinking of doesn't exist here. If the Earth were being swung around on the end of a rope, you would feel yourself pressed toward the Earth if you were on the inner side and pushed away from it if you were on the outer side, and that difference would show up on a scale. But the Sun's gravity accelerates you along with the Earth, so there's no such effect. There is a much smaller effect due to the change of the gravitational field with distance (the tidal force already mentioned), but it's not the same thing. For one thing it's symmetrical—on the near side you're pulled away from the Earth because you're closer to the Sun, on the far side you're pulled away from the Earth because it's closer to the Sun. For another thing the tidal force drops off with distance from the Sun, while a centrifugal force would increase with distance. -- BenRG (talk) 20:46, 2 November 2009 (UTC)

Oh please, not this silly quibble again. http://xkcd.com/123 . Oops, sorry, you were making a different point; I hadn't read carefully enough. --Trovatore (talk) 20:48, 2 November 2009 (UTC)

The weight will be greatest when the body is at right angles to the sun or moon, ie at dawn or dusk for the sun. Dmcq (talk) 20:49, 2 November 2009 (UTC)

I think BenRG has the right response. I'm pretty sure that what I'm trying to talk about is different from the tidal force, which I know and understand perfectly well. My alleged force would have different properties than the tidal force (read my original description), but if I understand BenRG correctly this effect is cancelled by the sun's gravity. Staecker (talk) 20:54, 2 November 2009 (UTC)

One way to think of it is that the Sun's gravity cancels the centrifugal force at the Earth's center. On the noon side of the Earth, the Sun's gravity is greater (because you're closer to the Sun) but the centrifugal force is smaller (because the angular velocity is the same, but the radius is smaller), so you're pulled towards the Sun. On the midnight side, the Sun's gravity is diminished, but the centrifugal force is larger, and pulls you out. --Trovatore (talk) 21:05, 2 November 2009 (UTC)

... of course this ignores the Earth's own rotation. The angular velocity on the noon side is not exactly the same as the angular velocity on the midnight side, because the Earth is spinning. I haven't worked out how much difference this makes. --Trovatore (talk) 21:44, 2 November 2009 (UTC)

Mass spec

If I wanted to conduct an analysis of a suite of polycyclic aromatic hydrocarbons in a solvent extract of soil using mass spectrometry in order to obtain information on the molecular masses of the constituents what sort of ionisation and insertion techniques should be used? Thanks 188.221.55.165 (talk) 20:01, 2 November 2009 (UTC)

I'm no analytic chemist, but it sounds like you're talking about GC-MS. Seems that's the way people are measuring soil contaminants these days (refs here: [18],[19],[20] will probably have more detail than WP:RD could provide). --- Medical geneticist (talk) 20:32, 2 November 2009 (UTC)

Banging your fists from a different perspective

The act of banging your fists on a table, a relatively common gesture, is usually displayed when someone wants to give their speech a firm and absolute meaning, or when that person is angry. What purpose does this gesture serve from an evolutionary perspective, that is, it obviously serves a purpose nowadays to humans, but is this gesture seen in other primates, and how does this gesture in particular serve us for a certain purpose, instead of using a different gesture. Any thoughts? —Preceding unsigned comment added by 201.21.180.57 (talk) 20:43, 2 November 2009 (UTC)

As a layman, I'd suggest that banging one's fist on the table is no more "innate" than rolling one's eyes; our article Gesture is woefully short but has some interesting-looking references. Comet Tuttle (talk) 20:47, 2 November 2009 (UTC)

Why make the assumption that this gesture must have an evolutionary "purpose" different than any other gesture? Fist thumping is a useful, easily interpreted gesture. Various primates (including humans) pound their fists on their chests... probably something having to do with trying to establish dominance or display aggression, etc. --- Medical geneticist (talk) 21:53, 2 November 2009 (UTC)

I'm not sure how biologically relevant it is (I can't find a WP article), but stereotypically male gorillas are thought to pound their chests with their fists in a gesture of physical dominance. Pounding the table could be a related gesture used to connote power and authority. -- 128.104.112.149 (talk) 22:06, 2 November 2009 (UTC)

Pounding with clenched fist an object such as a table is expressing an urge to Violence that is in conflict with one's unwillingness to hurt a person. Cuddlyable3 (talk) 22:10, 2 November 2009 (UTC)

. Comet Tuttle (talk) 22:31, 2 November 2009 (UTC)

See the article Frustration noting the examples. Cuddlyable3 (talk) 07:55, 4 November 2009 (UTC)

Can the Yarkovsky effect be used for space propulsion?

Say you build a probe that heats only part of its exterior using an internal radioactive source. Would you be able to get a net thrust out of this system because of the Yarkovsky effect? I looked around the net for things about such a mechanism but didn't really find anything. 189.15.218.71 (talk) 23:29, 2 November 2009 (UTC)

Heating only part of the probe would be hard. You would be better off heating all of it and painting different sides different colours so they emit differently (white on one side so it doesn't emit much, black on the other so it does). That kind of thing has been proposed for giving asteroids a slight nudge over a long period of time so they don't crash into the Earth. I've never seen it proposed for spacecraft propulsion. I guess it would work, but it would be really slow - there are better ways. --Tango (talk) 23:42, 2 November 2009 (UTC)

The problem is that radiation pressure at any reasonable temperature (i.e., a temperature low enough to not melt the propulsion system) is very small, generally measured in micropascals. So plenty of energy may be available from the radioactive source, but you're limited as to how fast you can use that energy, i.e., how much power the propulsion system can provide. That's why nuclear electric rocket designs instead use some kind of electric propulsion system such as an ion thruster, that uses some kind of reaction mass. Red Act (talk) 00:48, 3 November 2009 (UTC)

November 3

Mil vs Micron

Hi guys, Mil and Microns are measurements used to represent the thickness of plastic. Does any body knows how many microns are equal to 0.55 Mil? —Preceding unsigned comment added by Ferchyn (talk • contribs) 01:14, 3 November 2009 (UTC)

I would guess "Mil" is short for "millimetre" (one thousandth of a metre). A micron is an alternative name for a micrometre (one millionth of a metre). So there are 1000 microns in a mill. That means 0.55 Mil is 550 microns. And I would guess wrong - it's short for milli-inch. So the actual answer is 0.55 Mil is 13.97 microns. --Tango (talk) 01:25, 3 November 2009 (UTC)

(edit conflict) I was going to correct Tango, but now I don't need to. Our article is at Thou (length). Deor (talk) 01:33, 3 November 2009 (UTC)

Hmm, in my experience mil is much more common. Probably the article should be moved. --Trovatore (talk) 03:07, 3 November 2009 (UTC)

I agree, I've never even heard of thou. I'm sure mil is much more common. Red Act (talk) 03:13, 3 November 2009 (UTC)

Thou is more common in my experience. Perhaps it is a British vs American English thing (me being British)? --Tango (talk) 03:19, 3 November 2009 (UTC)

e/c Try this Mil to Micron conversion calculator. hydnjo (talk) 01:32, 3 November 2009 (UTC)

Worth noting is that Google supports unit conversions in their search field: Check it out. TenOfAllTrades(talk) 03:03, 3 November 2009 (UTC)

If thou is a British thing, then why don't we have the article at Mil (length), since the British use the metric system? —Akrabbim^talk 04:28, 3 November 2009 (UTC)

Should be, "if thou art a British thing". HTH. --Trovatore (talk) 04:30, 3 November 2009 (UTC)

Brits use a mixture of metric and imperial. If I need to gap a spark plug I know it's 25 thou, and I always used to gap distributor points to 15 thou. I wouldn't know (although could calculate or look up) the metric equivalent. We mostly inflate tyres to PSI and we always drive miles at MPH. Not very metric, really. --Phil Holmes (talk) 10:47, 3 November 2009 (UTC)

Oh, I didn't know that. Here in America, all the sciencey people that like metric spin the US as the last barbaric nation to still hold on to feet, pounds, and gallons. —Akrabbim^talk 12:10, 3 November 2009 (UTC)

No, there are 2 barbaric nations left ;-) Fribbler (talk) 13:19, 3 November 2009 (UTC)

Quite recently I was remarking to my wife how I have to mix units to understand the sizes of things without lots of consciuos thought. I only really know my weight in stones and pounds (which, I know, won't help in the US). I run a weather site and follow rain in mm and temperature in Celsius. I'm equally at home with metres or feet or yards. I can only think of fuel consumption in miles per gallon. I used to work on Integrated circuits and couldn't conceive of specifying them in anything other that microns - oh - except their diameter, which is inches. Such is life :-) --Phil Holmes (talk) 17:21, 3 November 2009 (UTC)

Hmm, you did do your silicon work a while ago, eh? The micron is still used (in the sense that no one says micrometer) but it's kind of too big to be a very useful unit. Sometimes comes up when talking about regions of a chip and stuff like that. --Trovatore (talk) 19:11, 3 November 2009 (UTC)

Best time to buy new houseplants?

I'm a beginning apartment gardener who's ready to move beyond philodendron and spiderplants. I've purchased and read a number of guides and feel ready to buy some new species specimens. I'd like to know if there are guidelines as to the best time to purchase new plants? None of my books have mentioned this, other than notes about protecting plants from cold/heat damage during transit from your nursery to your home. For example, I was wondering if buying plants in spring, when they're waking up and preparing for new growth, makes them more able to adapt to the climate difference in their new location? I'd rather not buy a nice selection of new plants now only to find that they've been too weak to successfully acclimate to their new home... I have an underfloor heated apartment in a climate roughly equivalent to Ohio. Thank you! 218.25.32.210 (talk) 01:29, 3 November 2009 (UTC)

Your indoor plants are going to have survive dry air conditions. It probably does not matter much when you buy them, but you may get a better price in the autumn when nurseries try to get rid of plants before frost kills them. Graeme Bartlett (talk) 08:29, 3 November 2009 (UTC)

You'll get a better answer if you just tell us the species you want to grow indoors. One thing you might consider is setting up a heated propagation area (using a heat mat, plastic hoods or vivarium-like enclosures) and instead of buying plants, just grow some from seed, choose the best one as a mother plant, and clone the rest with cuttings. You can do this with several different species, and this will allow you to have some redundancy; If one plant dies, you'll still have the others to work with. Viriditas (talk) 11:05, 3 November 2009 (UTC)

I actually find it better to buy the plants that are in flower when they are in flower, so I can see whether I like them or not! In the UK, houseplants in garden centres are generally on sale in heated greenhouses or similar environments, so they shouldn't need to acclimatise. --TammyMoet (talk) 11:30, 3 November 2009 (UTC)

Elements formed by a hydrogen bomb detonation

I've looked on many articles relating to nuclear processes but I haven't found anything particularly straight-forward on the elements created by an atomic explosion, especially hydrogen bombs, which produce high atomic mass elements. Could someone help find/add these elements and add them to an existing article? Much appreciated! Letter ⁷ _{it's the best letter :)} 01:55, 3 November 2009 (UTC)

I think the high atomic mass elements will be from the fission part of the bomb (ie. the bit that doesn't involve hydrogen). Nuclear fission product should contain the information you want, but note there aren't specific elements produced - there will be a mixture. --Tango (talk) 02:01, 3 November 2009 (UTC)

Much obliged! In my rush I didn't see that page, thanks again! Letter ⁷ _{it's the best letter :)} 02:09, 3 November 2009 (UTC)

Note that there are some elements that are formed by nuclear reactions other than fission in a bomb. See, e.g., Einsteinium, which is formed by the capture of 15 neutrons by U-238 (which is the sort of thing that you'll only find in a very high neutron economy, of course—like the inside of a bomb, or a particle accelerator). --Mr.98 (talk) 04:41, 3 November 2009 (UTC)

composite spectral waveform of each element

Have the composite waveforms (harmonic synthesis) of the frequencies and amplitude of the spectral lines for each element been published? Biggerbannana (talk) 05:41, 3 November 2009 (UTC)

What spectral line are you referring to ? If you mean the emission spectrum, you can find such data at (say) this NIST website. Abecedare (talk) 05:59, 3 November 2009 (UTC)

Yes, this page seems to point to the spectral data but without graphs and in particular the waveform of the composite emission spectrum for each element. Biggerbannana (talk) 06:18, 3 November 2009 (UTC)

The wavelength of the composite waveform is the Least common multiple of its component wavelengths and likely to be extremely long i.e. of low frequency. Cuddlyable3 (talk) 11:05, 3 November 2009 (UTC)

The composite waveform does not really exist. One atom will emit one photon of a particular colour, and the waveform will depend more on how you measure it. Different colours from an aggregate of atoms will be emitted incoherently and will not be in phase with each other. This will mean there is not a particular wave shape. The overall spectrum will vary with temperature, pressure, magnetic field and turbulence, and even electric field. Graeme Bartlett (talk) 10:36, 4 November 2009 (UTC)

DIY amatuer water quality testing for real nasties like mercury, et al ?

Is it possible for someone without a mass spectrometer // well-equipped laboratory to test water quality for things beyond pH and dissolved oxygen levels? Are there kits one can buy that would reliably identify the presence of heavy metals and such? Or is the only recourse to send a sample to a lab? 218.25.32.210 (talk) 05:48, 3 November 2009 (UTC)

I've seen at home test kits for mercury, lead, and nitrates. Also things like water hardness and sodium content, but those have less to do with whether the water is potentially harmful. Dragons flight (talk) 06:02, 3 November 2009 (UTC)

Yes. Aquarium hobbyists measure a range of variables in the aquarium water. These are either test-strips or fluids you mix with water samples and they change colour depending on the concentration of various chemicals. These are available from websites and pet stores. Checking the website of JBL I find test sets for: Iron, copper, ammonium, phosphate, Nitrite, Nitrate, silicic acid, CO2 concentration and Gh and Kh measures of hardness, plus separate calcium measures and a magnesium + calcium indicator.

I also know that in parts of india, the groundwater is tested for arsenic with similar and supposedly inexpensive equipment. EverGreg (talk) 09:49, 3 November 2009 (UTC)

Mass spec isn't usually used for testing heavy metals in water. Inductively coupled plasma spectroscopy is more common. Rmhermen (talk) 15:26, 3 November 2009 (UTC)

aluminum-zinc alloys

Help! I'm trying to find a phase diagram for this system and am getting confused. In the first google images hit I find, I get alpha and alpha prime being in the same phase region?! Help?! John Riemann Soong (talk) 06:16, 3 November 2009 (UTC)

Information on shoulder/chest area anatomy (Medical Science)

Hi, I am writing a novel and I'm trying to make it as realistic as possible (sometimes to a brutal extent). I've come to a point where I need in depth medical information and my local doctor is indisposed. It's also tough to gleam the information I need from several (incomplete) diagrams. So here we are.

Be forewarned, the information I need is for a particularly descriptive(/brutal/violent) fighting scene.

I need to know if there is a name for the area between the shoulder and neck, that is to say, between the Clavicle and Scapula, as this is the point of entry of the character in question's sword. That would be the first part of my question. The second being: I also need a listing of tendons, muscles and organs that a 50cm sword would puncture/cut, if such an action was possible (Not obstructed by bones, etc). Or a source where I can get this. It may carry more relevance than simply determining whether the heart will be among this list, so I will include that it is on the right side of the individual. If the lungs are among this list (Which I believe it will be), am I correct in assuming the individual will cough or gurgle blood in his final moments?

Thank you in advance (In case this question isn't appropriate on this format, I do apologize. I must admit it was rather unclear to me at the time of this posting.) —Preceding unsigned comment added by RyuGenkai (talk • contribs) 09:52, 3 November 2009 (UTC)

Well, that's a nearly 20 inch sword. You can cut anything within 20 inches of where you stab, by aiming at it. Straight down, on the right, you'd hit the apex of the lung, the lung, the diaphragm and probably reach also have the liver en brochette. On the left, the apex of the lung, the pericardium, the heart, the diaphragm and the stomach. Should you decide to go sideways, you could probably get a lung-heart-lung shishkabob. You could cause bilateral pneumothorax and cause death by suffocation without any coughing or gurgling of blood, or if it make for a more dramatic scene you could have blood coughed everywhere. You could transect the carotid and have blood spurting out of the neck, or for a more subdued and dignified death, transect the aorta within the chest cavity and have the victim bleed to death internally with no mess on the carpet. Which is to say: big murder weapon can cause about anything entering about anywhere. Anyway, you should have a look at apex of the lung, which is the area you're entering, and you may get some idea of the anatomy of the area by looking at sternocleidomastoid muscle, scalene muscles, and File:Musculi_coli_base.svg. - Nunh-huh 10:15, 3 November 2009 (UTC)

If I recall correctly, in Rome (TV series) Marcus Tullius Cicero was assassinated "execution style" by veteran soldier Titus Pullo (Rome character), who killed him with a downward sword thrust similar to the one you describe, as if it were a standard way of killing. In actual history, this is not documented. Edison (talk) 14:32, 3 November 2009 (UTC)

Thanks folks. Yes, I did mean straight down, don't know why I omitted that. I did say 50cm, but I'm assuming even with the momentum the character has (He's jumping down from above his victim) he won't bury it up to the hilt. At least not with the (limited) knowledge I have of Physiology. I've always had the opinion that humans are a lot more resilient than books and movies make them out to be. I am liking the pneumothorax idea - it opens up new options. I must admit I also have never heard of a historical case of killing in this way, but then again, my character isn't much for history. Nor is he very experienced in the killing business, shall we say. This is the best method he could come up with when presented with a drop from elevation onto the target. RyuGenkai (talk) 16:14, 3 November 2009 (UTC)

What sort of author capitalizes common nouns like 'physiology,' 'clavicle' and 'scapula.' DRosenbach ^{(Talk | Contribs)} 20:43, 3 November 2009 (UTC)

One whose first language is German? Googlemeister (talk) 15:38, 4 November 2009 (UTC)

The film Torn Curtain is notable for a murder scene "that Hitchcock made specifically to show the audience how difficult it is to kill a man". 81.131.65.113 (talk) 21:38, 3 November 2009 (UTC)

melanin benefit vs cancer risk

Melanin seems to prevent damage to DNA by keeping free radical generation at a minimum. Its deficiency appears to be associated with genetic abnormalities. Is there a "Goldy Locks" level (not too hot and not too cold) of melanocytes to maximize benefit and minimize risk tht can be achieved through selective breeding? Biggerbannana (talk) 13:18, 3 November 2009 (UTC)

I assume that would vary by the exposure in question, right? That's why melanin content varies in human populations by latitude. The averages of human skin pigments of historic populations at given latitudes is probably close to an ideal "level" for that given latitude, with evolution having found the sweet spot for that level of exposure. --Mr.98 (talk) 13:41, 3 November 2009 (UTC)

Actually I mean amount of melanocyte cells rather than melanin assuming more cells produce more melanin in total. Biggerbannana (talk) 13:49, 3 November 2009 (UTC)

Our articles on melanin and melanocyte don't appear to mention any association with genetic abnormalities. Do you have some source for that could be used to improve the articles? 75.41.110.200 (talk) 15:16, 3 November 2009 (UTC)

The very article you linked to says "The difference in skin color between fair people and dark people is due not to the number (quantity) of melanocytes in their skin, but to the melanocytes' level of activity (quantity and relative amounts of eumelanin and pheomelanin). This process is under hormonal control, including the MSH and ACTH peptides that are produced from the precursor proopiomelanocortin." I didn't know this for sure before I read the article but expected it would be very likely for there to be a big difference in the regulation outside the number of cells as many/most? human systems have rather complex regulation. Nil Einne (talk) 16:20, 3 November 2009 (UTC)

Has now been by blocked User:TenOfAllTrades, check WT:RD for more. Nil Einne (talk) 16:26, 3 November 2009 (UTC)

How is heat transfered from one body to another?

and no not a homework question, I assumed it was by the vibrating or moving particles in the hotter substance banging off the particles in the cooler substance/the air in between and causing them to vibrate or move as well. Is that true? —Preceding unsigned comment added by 92.251.255.16 (talk) 17:04, 3 November 2009 (UTC)

Start with our heat transfer article. DMacks (talk) 17:07, 3 November 2009 (UTC)

The OP describes heat conduction. The other two ways of heat transfer are radiation and convection. Cuddlyable3 (talk) 20:05, 3 November 2009 (UTC)

Sometimes - and to some degree, yes - it's true - but it's not the only way.

• The molecules in the hot object are jiggling around - if they bash into the molecules of some cooler object (which aren't jiggling around as much) then some of the motion gets transferred so the hot object jiggles less than it was before and the cool object jiggles more than it did before - in other words, heat flowed from the hot object to the cooler one. That's "conduction".
• However, there is a second mechanism - hot objects emit infra-red light (or visible light if they are VERY hot..."glowing red hot" as we would say). That energy is lost from the hot object - and when that infra-red light hits something else, that object gains energy and heats up. That's how you can feel the heat from a fire - even though the air between you and the fire isn't all that hot. This is "radiant heat transfer".
• The other mechanism that people talk about is "convection" - which really only happens in fluids (gasses and liquids essentially) that are in contact with some hotter or cooler material. A pocket of fluid that's in contact with some hot object will get warm (by either conduction or radiation) - and that hotter region of the fluid expands and becomes less dense - which causes it to rise up and be replaced by cooler fluid that circulates in to replace it. As that hot pocket of fluid moves upwards, some cooler fluid flows in and is now in contact with the hot object and can remove more heat as it too expands, moves upwards and is replaced. The moving fluid (be it gas or liquid) carries the heat away - and can transport it faster than mere conduction through the fluid would be able to.

If conduction were the only mechanism, then heat from the sun would be unable to reach us because of the 93 million miles of vacuum between there and here!

But these are only partial descriptions. The hot flame from a coal fire can boil water, the steam can turn a generator, electricity can carry the energy away - be stored in a battery for six months - then used to spin a motor - whose friction produces heat. In a sense, this is yet another heat transfer mechanism. However, classically we talk about conduction, radiation and convection as being the only three ways it happens. Personally, I don't think convection counts - it's just the consequence of either conduction or radiation (and probably both)! However, if this actually IS homework - you'd better mention convection and not boiling-water/steam/generator/electricity/battery/motor/friction or any other of the bazillion ways heat is "transferred" - because that's just how homework is.

SteveBaker (talk) 04:10, 4 November 2009 (UTC)

Furthermore, convection is complicated in that it actually involves 2 processes; the transfer of energy from molecule-to-molecule via collisions, AND mixing of molecules of different energies. Since temperature is a bulk property of matter, I can have two theoretical systems:

• The first system has 50% of its molecules at energy = A; and 50% and energy = B
• The second system has 100% of its molecules at energy = C; such that C is the average of A and B

Both of these systems are at the same temperature, however both are very different thermodynamically; the first system is at a higher entropy for example. How each of these systems react when brought into contact with a third system is very different; and yet since temperature is the ONLY practical means we can measure thermal energy, it makes these issues in detail much more complex than they seem in general. --Jayron32 21:27, 4 November 2009 (UTC)

What species is the mushroom in this photo?

I have taken a set of five photos of some mushroom I found in the coastal forest of Poland in October 2009. I think the images have high value but I do not know the type of mushroom in the photos. I have five images in the total set. Here is one of them File:Unidentified_red_mushroom_in_Poland_in_October_2009.jpg and I can post more if need to help identify it. Jason Quinn (talk) 18:00, 3 November 2009 (UTC)

Amanita muscaria or fly agaric --Tagishsimon (talk) 18:07, 3 November 2009 (UTC)

That was the first species I found but I don't think it is correct. The mushrooms in my photos (there are the two you see in this photo and a third one in pictures I haven't posted yet) are flatter and less bell-shaped. Jason Quinn (talk) 18:10, 3 November 2009 (UTC)

Actually, maybe you are correct. Some of the other pictures of them show them to flatter sometimes. I'll wait for more opinions. Thank you. Jason Quinn (talk) 18:12, 3 November 2009 (UTC)

If you Google image amanita muscaria there is a surprising number of forms displayed. I can't believe that the labelling is so bad. The other point to note is that the cap changes shape as it ages.It opens from an egg shape and will flatten as it matures, some even curling up at the edge, in the final stages before they decompose. Richard Avery (talk) 18:22, 3 November 2009 (UTC)

Coming here from WikiProject Fungi, that's almost certainly a fly agaric. Our article is already very well illustrated, but a few more in the Commons gallery couldn't hurt. J Milburn (talk) 10:20, 4 November 2009 (UTC)

• 
  Photo 1 of 5
• 
  Photo 2 of 5
• 
  Photo 3 of 5
• 
  Photo 4 of 5
• 
  Photo 5 of 5

Based on the feedback I received. I have uploaded my set of five photos to the Wikipedia Commons with the mushroom identified as amanita muscaria. The gallery above shows the images. Note that in image 4 you can clearly see the gills under the cap on the mushroom on the right, which may help you experts with the classification even more. Strangely, 4 of the 5 pictures show flies standing on the mushroom but the Wikipedia page says the mushroom is poisonous to flies. Either these flies have a death wish or something else is going on. Jason Quinn (talk) 14:28, 4 November 2009 (UTC)

Noon in the tropics

Would the variation of the position of the sun, at noon, in the tropics be noticeable. Presumably at some times of the year it is due north, and at others due south. Would it be noticeable? Stanstaple (talk) 18:26, 3 November 2009 (UTC)

Yes. My Dad used to live in Kuala Lumpur (latitude 3 degrees north) and his condominium had a swimming pool. The temperature of that pool varied widely at different times of the year because the sun would go one side of the building at one time of year and the other side 6 months later. That means that during dry season the swimming pool spent quite a long time in the shadow of the building and during wet season it was in the sun almost the whole time, so was much warmer during the wet season. --Tango (talk) 18:51, 3 November 2009 (UTC)

Just as in other places, the position of the sun in the sky at the same time of day has range of about 47° (twice the tilt of the Earth's axis) depending on the time of year. Rckrone (talk) 20:14, 3 November 2009 (UTC)

47 degrees doesn't really mean anything to me viscerally- i very much notice that the day is shortening dramatically at my latitude- the day goes from bright from four till eleven to eight till four- i just wanted to compare Stanstaple (talk) 21:58, 3 November 2009 (UTC)

The length of the day doesn't change considerably in the tropics because the Sun goes from 23.5 degrees one side of directly overhead to 23.5 degrees the other side. --Tango (talk) 22:45, 3 November 2009 (UTC)

ptsd

if you had ptsd how long does it last —Preceding unsigned comment added by 24.98.148.83 (talk) 19:43, 3 November 2009 (UTC)

You mean Posttraumatic stress disorder? According to Posttraumatic stress disorder#Diagnosis, it has to last more than a month to count as PTSD. I think it can last the rest of someone's life in some cases. --Tango (talk) 19:49, 3 November 2009 (UTC)

OR my father had PTSD arising from his treatment in a Japanese POW camp during WW2. It lasted until the day before he died 60 years later. Of course it was never treated, as PTSD was only recognised as a treatable condition comparatively recently. --TammyMoet (talk) 10:44, 4 November 2009 (UTC)

Glitch in thermochemistry calculation

Okay, so I have this little problem:

A 100-gram rod of copper (specific heat 0.385 J/g) at 100ºC is immersed in 50 grams of water (specific heat 4.18 J/g) at 26.5ºC. What will the temperature be when both components achieve thermal equilibrium?

And I have tried to solve it as follows:

• From the information given, we can calculate that when copper cools by 1ºC, it releases 38.5 joules. On the other side, water needs 209 joules to gain 1ºC.
• Therefore, we can produce the following equations:

$100-x/38.5=y$ and $26.5+x/209=y$

where x represents the amount of joules gained/lost by the component, and y represents the temperature of the component.

• To know where the equations intersect, we make them equivalent:

$100-x/38.5=26.5+x/209$

• We simplify:

$x=2,371$

• Now that we know that each component has gained/lost 2,371 joules, we can use that in the original equation to find out the gain/loss of temperature. Let's do it for copper:

$100*0.385x=-2,371$

$x=-2,371/38.5$

$x=-61.59$

• Therefore, that means that copper has lost 61.59ºC, i.e. its temperature at equilibrium is 38.41ºC. Nevertheless, my textbook gives a value of 37.9ºC. Did I make a mistake, or is this small deviation due to differences in rounding up/down numbers? Thank you. Leptictidium (mt) 19:52, 3 November 2009 (UTC)

I think you made an error simplifying - I get x=2389.566667, albeit on the back of an envelope and as yet unchecked.

$100-x/38.5=26.5+x/209$

$73.5-x/38.5=x/209$

$73.5=x/209+x/38.5$

$8046.5*73.5=38.5x+209x$

$8046.5*73.5=247.5x$

$2389.566667=x$

$100*0.385x=-2389.57$

$x=-2389.57/38.5$

$x=-62.06675325$

$100-62.06675325$

$37.93324675$

$37.9$

--Tagishsimon (talk) 20:17, 3 November 2009 (UTC)

I'm sorry for asking what is probably a very stupid question, but where does the 8046.5 come from? Leptictidium (mt) 20:48, 3 November 2009 (UTC)

It's 38.5*209 ... just some convenient figure allowing me to get rid of both fractions. --Tagishsimon (talk) 20:51, 3 November 2009 (UTC)

Technically specific heat is temperature-dependent -- heat capacity falls as temperature decreases (it is zero at 0K). If you have 1 mol copper at 0C and 1 mol copper at 100C, their equilibrium temperature will actually be higher than 50C, because for each joule of heat transferred, the colder object increases in temperature faster than the hotter object falls in temperature per joule of heat. (This is what makes heat transfer from hot to cold thermodynamically irreversible.) John Riemann Soong (talk) 16:43, 4 November 2009 (UTC)

Yes, but that level of accuracy isn't usually taught to first-year chemistry students, with good reason. First, one must understand the concept of specific heat before one can deal with the issue of temperature dependence of specific heat. The OP does not indicate what chemistry class he is taking, but it is likely this is simply general chemistry. --Jayron32 21:19, 4 November 2009 (UTC)

Note: There is also another way of working it out

1. 100g copper going from 100°C to 26.5°C would release 100*0.385*(100-26.5) = 2829.75 J

2. Sum the copper and Water heat demands (also known as a "Water Equivalent") 50*4.18 + 100*0.385 = 247.5 J/K (wt * Cp = g * J/g/K = J/K) (Cp units are J/g/K not J/g as you shown above)

3. Divide (1) by (2) for the temp rise for the combined copper/water system 2829.75/247.5 = 11.4333K

4. Add (3) to the start temp = 26.5 + 11.4333 = 37.9333°C

•  Ronhjones  ^(Talk) 21:39, 4 November 2009 (UTC)

looking at yellow or bright purple stuff for a long time

From my personal observence, okay I wear yellow goggles at night when I sleep. When I wake up when I take off the yellow goggle I still see white stuff for white. If humans look at yellow or purple stuff for a long time I thought white stuff will stay white, and it will not look blue or lime green. Since when I took off the yellow goggle I didn't see white as blue. Will yellow and purple just look less vivid? --209.129.85.4 (talk) 20:22, 3 November 2009 (UTC)

The human brain compensates for ambient light (wearing yellow goggles would be the same as having the room illuminated by a yellow light). You know what things ought to be white and your brain works out what the ambient light must be and then compensates for it so you see things the colours they would be under white light. If you were in unfamiliar surroundings and didn't know what colours things should be, then your brain might get it wrong or it may take some time to work it out. --Tango (talk) 20:34, 3 November 2009 (UTC)

Why do you wear yellow goggles when you sleep? Looie496 (talk) 20:39, 3 November 2009 (UTC)

Corneal transplant--209.129.85.4 (talk) 20:55, 3 November 2009 (UTC)

I do not think that the brain will know that you are wearing yellow goggles when you sleep because your eyes are going to be closed and it will presumably be dark. What colors do you think there are that need compensation under those conditions? Googlemeister (talk) 15:34, 4 November 2009 (UTC)

UFO identification

I snapped these beautiful critters on Sunday at the Kirstenbosch National Botanical Garden. Can anyone please help identify them? Also, please advise if these pics are the best of their type and pick the best ones between the duplicates. I'm loathe to upload the full res versions if we already have better pictures in our articles. Also, anyone with a good eye for composition feel free to crop these photos (or even just draw borders on the existing) as you see fit. The full res pics are 8MP so I should be able to throw away plenty of pixels and still have something usable.

Photographic critique would be greatly appreciated. Also what's the best way to go about editing these? They are taken with a Canon EOS 350D in Adobe RGB color space, will The GIMP handle it properly? (The low-res versions have been created with Windows Image Resizer PowerToy, causing some colour "bleeding" which I put down to it not playing nice with Adobe RGB.) Or should I just upload the originals and request our WP:Graphic Lab to do the touching up? Regards. Zunaid 20:37, 3 November 2009 (UTC)

Dropped by further to message on the WP:photo page. Don't have enough time to upload crops, but here's my 2¢... calling them #1 to #7, clockwise from top left: 1 is a good in-flight shot and more worthy of gallery space than others there, crop slightly (15%) from all sides except top; 2 is better than 3 by far, crop as before, possibly a little tighter than before, try 25%; 5 is ok but probably doesn't illustrate so much more than the others on the page that I'd want to find space for it; 6 needs heavily cropping from all sides before I can even evaluate it; 7 has more detail in the body than 4 and tells me more about the wings, could do with a 20% crop from the right and is really very nice, be a shame not to use it somewhere. I'd put these up at about 1500x1000px to be of real value, and if you're getting weird results with colour profiles maybe the Lab would be a good idea, I'm not sure the GIMP handles profile conversion any better than WIRPT. Hope that's been some help. mikaul^talk 05:33, 5 November 2009 (UTC)

• Carpenter bee, Xylocopa sp. Crop me please! I've got more pictures of these but does the article really need more?
  Carpenter bee, Xylocopa sp. Crop me please! I've got more pictures of these but does the article really need more?
• 
  Valley carpenter bee, Xylocopa varipuncta. Slightly clipped on top but in focus.
• 
  Valley carpenter bee, Xylocopa varipuncta. Not clipped off but slightly out-of-focus. which one to choose?
• Acraea sp., Heliconiinae. Identify the flower. Does the article need this pic?
  Acraea sp., Heliconiinae. Identify the flower. Does the article need this pic?
• Acraea sp., Heliconiinae. Which pic is best?
  Acraea sp., Heliconiinae. Which pic is best?
• Chafer beetle, Scarabaeidae. Identify the flower. Crop needed?
  Chafer beetle, Scarabaeidae. Identify the flower. Crop needed?
• 
  Oxythyrea sp. Identify the flower. Crop needed? Is this photo needed? The article has much better close-ups.

I don't know the answer, but I put them in a gallery for you so I thought I'd leave a message to let you know. They're beautiful, but I don't see much photography. Vimescarrot (talk) 21:08, 3 November 2009 (UTC)

Thanks. I've edited some captions. Check out the pics in our bee article for some REALLY superb photography. This is rather second-rate in comparison. Zunaid 21:26, 3 November 2009 (UTC)

The first one is a carpenter bee, Xylocopa sp.. The last one is Oxythyrea sp. (I'm going to write a stub article for that one soon). The butterfly species name eludes me for a moment, but it will come back to me in a minute or two. --Dr Dima (talk) 23:14, 3 November 2009 (UTC)

Done: Oxythyrea article stub is up. --Dr Dima (talk) 06:56, 4 November 2009 (UTC)

The before-last one (middle one in the lower row) is also a chafer beetle, family Scarabaeidae; there is not enough resolution to make a more accurate identification. --Dr Dima (talk) 23:47, 3 November 2009 (UTC)

The butterfly in pictures 4 and 5 is Acraea sp. (Heliconiinae). --Dr Dima (talk) 03:18, 4 November 2009 (UTC)

Thanks for the ID's so far Dr. Dima. Photographic critique and input needed. A lot of the linked articles already have sufficient (and better IMHO) photos. Are these pics really then needed? Is there any other noticeboard I can spam for photographic input? Zunaid 10:51, 4 November 2009 (UTC)

The second and third picture, the yellow carpenter bee, is most likely a male Xylocopa varipuncta, commonly called the Valley carpenter bee. Bugboy52.4 | =-= 01:08, 5 November 2009 (UTC)

Thanks. Do our articles really need these pictures? Especially when compared to those already in the articles? Should I upload high res versions? Zunaid 04:55, 5 November 2009 (UTC)

vision acuity over 20/400

Is this possible to have vision over 20/400. Do anybody have like 20/1000 or 20/700. From corneal scar I have had my vision was 20/400--209.129.85.4 (talk) 20:56, 3 November 2009 (UTC)

This article [21] implies that such Snellen fractions do exist. --Cookatoo.ergo.ZooM (talk) 21:14, 3 November 2009 (UTC)

Well, only being able to detect light and dark as if your eyes were closed could be described as 20/infinity. --Tango (talk) 22:15, 3 November 2009 (UTC)

If you consider what those two numbers mean, it's clear: 20/100 (for example) would mean a person who is only able to read letters that a normally-sighted person can read at 100 feet if they move to 20 feet away from them. For there to be 20/1000 vision, you'd have to be only just able to see letters at 20 feet that someone with normal vision could see at around two tenths of a mile! Normal vision allows you to recognise letters when they subtend only 1/12th of a degree. So for someone to have 20/1000 vision would mean that they'd only just be able to read letters about 18 inches tall from 20 feet away. SteveBaker (talk) 03:44, 4 November 2009 (UTC)

It doesn't have to be letters. It's just about resolving an image, whatever that image may be. The page linked to says the common way to measure 20/1000 vision would by getting to person to count fingers, in this case at 8 feet distance (although you would just report "CF 8'" rather than converting it to 20/1000). I guess that means that someone with normal vision can distinguish fingers at 400 feet (which sounds about right to me). --Tango (talk) 03:56, 4 November 2009 (UTC)

Isn't vision worse then 20/400 classified as legally blind anyways? Googlemeister (talk) 15:31, 4 November 2009 (UTC)

Depends on jurisdiction, but about that. There is more to life than whether or not you can claim benefits, though. --Tango (talk) 17:32, 4 November 2009 (UTC)

Human - 23 chromosome pairs

What happens when one is born with more or less than 23 pairs? --Reticuli88 (talk) 21:39, 3 November 2009 (UTC)

It will cause one or another disease. There are many, depending on which chromosome was duplicated/deleted. See Aneuploidy. Someguy1221 (talk) 21:43, 3 November 2009 (UTC)

The result will be a genetic disorder, not a disease. DRosenbach ^{(Talk | Contribs)} 02:40, 4 November 2009 (UTC)

Well, technically it will "kill" the potential life (well before birth approaches), and the (semi-)survivable diseases caused by the monosomy and trisomy Someguy refers to are the rare exceptions. ~ Amory (u • t • c) 22:34, 3 November 2009 (UTC)

Indeed. Miscarriage is often caused by a fault in the genes. --Tango (talk) 22:42, 3 November 2009 (UTC)

According to the disease link - "A disease is any medical condition that impairs bodily function." Some genetic disorders will impair bodily function and will therefore be be diseases. In reality I'm struggling to think of a genetic disorder that would not impair bodily function. Richard Avery (talk) 08:38, 4 November 2009 (UTC)

It wouldn't be a disorder if it didn't impair bodily function, it would be a neutral or beneficial mutation. Was anyone questioning the definition of disease? --Tango (talk) 17:42, 4 November 2009 (UTC)

Biological distinction between Sickness and Contagiousness in Contagious diseases.

I understand that people can be contagious but not ill during the incubation stage of a disease. The opposite, being ill but not contagious, is commonly said to exist at the tail end of a disease. What is going on biologically during both of these periods? I'm starting to think that latter is a bit of folk science invented by ill people who are feeling cooped up and better enough to want to rejoin the world. -Craig Pemberton (talk) 23:12, 3 November 2009 (UTC)

Certainly not. Infections are only contagious if they can be spread from person to person either directly or indirectly. If infectious particles exist in bodily fluids like sputum, semen and feces, spread can occur when shaking hands with an infected individual allows for a closed fecal-oral route of transit. That's great for transfer of things like E. coli and Hepatitis A. But certain infectious organisms do not congregate in fluids -- they may prefer to hide in other places (if not entirely, then at least for some portion of their infectious existence) or take on a noninfectious form when they are in certain fluid. Syphilis, for example, has three clinical phases -- patients with secondary syphilis are the most infectious, even though the infectious spirochetes are present from the time of inoculation. DRosenbach ^{(Talk | Contribs)} 02:53, 4 November 2009 (UTC)

But why or how would an organism become noninfective. It would essentially be committing suicide if it did so willingly. -Craig Pemberton (talk) 03:57, 4 November 2009 (UTC)

A pathogen is incapable of "becoming noninfective... willingly", as neither bacteria nor viruses have a free will. Rather, the outcome is decided by a competition between the pathogen and the immune system of the host. A viral or bacterial infection only rarely results in the death of the host. (That depends on the species of the pathogen and on the immune response of the host, of course). In most cases, pathogen is completely neutralized by the immune system of the host; at this stage the host no longer emits the pathogen. In some cases pathogen survives, and the infection becomes chronic and/or asymptomatic. In those cases the host remains a carrier of the pathogen, and may transmit it to others. --Dr Dima (talk) 05:41, 4 November 2009 (UTC)

Of course free will is an illusion, but people use it all the time. What I meant was that if information in it's own genome shut it down, why? And if information in the human genome shut it down, how? And if the disease is inactivated then why are you still considered sick? This is what I have now: the human immune system becomes able to neutralize the germs and quickly does so. The person still shows symptoms because it takes a while to repair the damage. -Craig Pemberton (talk) 16:47, 4 November 2009 (UTC)

It may be helpful to remember that the feeling you get of "being sick" is not entirely caused directly by the pathogen, but also includes your body's response to that pathogen (or, in the case of allergies, the body's response to something mundane). For example, fever often accompanies an infection such as the influenza, but many respiratory viruses prefer (or require) slightly cooler areas to do their dirty work. What's going on? Your body is raising its core temperature to help the fight against the infection. At other times, your body will react in a way that also suits the virus. For example, a runny nose helps flush the virus from your sinuses, but also aids the virus in spreading by releasing infectious material. But your incredibly complicated immune system sometimes runs rampant and sometimes simply keeps running after it no longer needs to. So, while your nose may be running as part of your body's attempt to flush your sinuses, the virus may now be long gone. This is apparently quite common when it comes to cough (OR alert) - coughing irritates your windpipe, which leads to... coughing... which irritates your windpipe. Your infection may be dead and gone for weeks and yet you keep on coughing because your throat is so badly worn out. I've had that situation (as diagnosed by a doctor): stop the cough by any means necessary for even a day or so and the rest of the problem just collapses. So, I was hacking like a hound-dog for a month but was completely non-infectious. Matt Deres (talk) 17:55, 4 November 2009 (UTC)

If "Big bang" is accurate...

If the universe's big bang beginning is accurate, then at that time all matter was together. We are also told that the light from distant galaxies hasn't made it all the way across the universe yet. I imagine that there is lots of relativity and stuff involved, but surely for both statements to be true some matter needs to have moved at faster than the speed of light. What am I misunderstanding? -- SGBailey (talk) 23:36, 3 November 2009 (UTC)

Actually, we can see almost all the way to the big bang itself. Just a short while after the big bang, the universe became clear and light could start traveling. We can see back to this wall and it is called the cosmic microwave background radiation. But events which happened too recently for light from them to reach you, you cannot see yet. Even when you pour yourself a cup of coffee you can't observe it for a time = armlength/C. -Craig Pemberton (talk) 23:46, 3 November 2009 (UTC)

It's generally assumed that everything in the universe came from one place, because it's hard to see how it could be so homogeneous otherwise. So it's all in our past light cone. But we can't see everything. The picture is something like this:

                           * /\           ^
                      @     /  \          |
                           /    \         |
                     ##################  time

We're at the top center and #### is the primordial fireball (the source of the cosmic microwave background). We can't see the event marked *, but we can see the matter that later does *. We can't see the event marked @ and we also can't see the matter that later does @, because the universe is opaque below the ####. But in principle if you extend the diagonal lines through the fireball they encompass the whole universe. The "edge of the visible universe" is defined by where the light cone hits the fireball. -- BenRG (talk) 00:51, 4 November 2009 (UTC)

We need to be careful with our terminology. You are using "universe" to mean "observable universe" (which means everything that can be theoretically observed, not just things that can be observed using EM radiation). Anything outside the observable universe can't have any impact on us, so in a sense we can just say it doesn't exist (which is why people do often abbreviate the observable universe to just "universe"), but in another sense it is very likely that it does (the size of the universe happening to exactly correspond with the size of the observable universe would be a massive coincidence unless there is something going on that we don't know about - alternatively, the universe could be smaller than the observable universe, in which case we should be able to see the same objects multiple times as the light goes all the way around the universe). --Tango (talk) 01:00, 4 November 2009 (UTC)

The expansion of the universe isn't matter moving outwards through space, it is the space itself expanding. There is no speed of light limit on the expansion of space, just on matter moving through space. See Metric expansion of space. The standard analogy is blowing up a balloon with dots on it. The dots are stationary compared to the bit of balloon they are on, but they move apart from each other as the balloon expands. The further apart they are, the faster they move apart. For objects far enough away from us, they are moving away from us (or, rather, the distance between them and us in increasing - they aren't actually moving, that's the point) faster than the speed of light. At the moment, the relevant distance is about 45 billion light years, I believe. --Tango (talk) 00:07, 4 November 2009 (UTC)

Many processes in physics are reversible. If no rules of physics are violated when "space" expands, then could it similarly contract without violating any law of physics? Hypothetically speaking, could the space between planet A and planet B (initially 10 light years) contract to .1 light year, making a trip between them much more convenient, so that it could be completed at .01 c in 10 years? By definition, there would be no faster than light travel. If we cannot explain why space expanded, can we set limits on the geometry of any future expansion (or useful contraction)? Edison (talk) 04:26, 4 November 2009 (UTC)

Yes, metric expansion can run in reverse. It's not expected to ever happen in our universe, but a Big Crunch was once hypothesised as a possible end of the universe. I don't think it would make interstellar travel easier, though - if the universe contracted far enough to make a different within a single galaxy then I think it would pretty quickly end up destroying any habitable systems. --Tango (talk) 17:50, 4 November 2009 (UTC)

Question - Metric expansion of space says there are two reasons for expansion: inertia and a repulsive force. Inertia is a property of matter and forces act on matter so it sounds like expansion is matter just moving apart. I understand (from reading this desk) that the velocity at which an object moves away from us can be more than c because time (in that measure of velocity) is based on a clock moving with the object which slows down as it moves. My question is: how do the two reasons above "fit" with space itself expanding? Zain Ebrahim (talk) 08:15, 4 November 2009 (UTC)

I'm not entirely sure about this bit (BenRG has tried to explain it to me, but I've never been entirely convinced). Even excluding the cosmological constant (which models that repulsive force you mention), the expansion isn't just inertia as we would usually consider it. It is caused by inertia, but that inertia causes the space itself to expand, that allows greater than light speed expansion. --Tango (talk) 17:50, 4 November 2009 (UTC)

Note that in the balloon example, inertia of the balloon surface itself (or tiny little pieces of lead fixed to the surface, if that's an easier analogy) would pull the balloon further apart, and even in a way that the distance between any two pieces on the surface would grow faster than the distance between the same two pieces in 3-D space. --Stephan Schulz (talk) 18:08, 4 November 2009 (UTC)

Can the "balloon" have "outward" "inertia"? The "outward" direction isn't really a direction at all from the perspective of someone on the balloon. I don't have a good understanding of this topic, but this seems very strange to me. Rckrone (talk) 23:44, 4 November 2009 (UTC)

The balloon, yes, certainly. Matter in the real universe - I don't know, but I suspect so. Otherwise, the interia vs. gravity argument makes no sense. --Stephan Schulz (talk) 13:11, 5 November 2009 (UTC)

Scratches head... Um, a quick break for a WP:OR or WP:SYNTH might be helpful! I don't particularly think Wikipedia is for writing essays on theoreticals like this. Don't make me insist you all find citations! This isn't a defined talk page so I think that means I can request them :) ♪ daTheisen(talk) 16:01, 4 November 2009 (UTC)

Our priority here is answering the OP's question in a way they can understand. If linking them to a reference they can read for themselves is the best way to do that, we'll do it. If writing out a detailed answer ourselves is better, we do that. Finding citations isn't really necessary unless there is a dispute. --Tango (talk) 17:50, 4 November 2009 (UTC)

Thanks all. I don't think I understand it as well as I want yet, but I understand it more than I did. -- SGBailey (talk) 11:44, 5 November 2009 (UTC)

November 4

Spiritual Science. Rectifying Hypotheses

can i create my own hyperlink-web here of my findings and studies with this 'spirituality'? i believe people would be interested in these things. i simply would like to be recognized as the author. please tell me my options. i simply want this question answered, i will not waste my time. —Preceding unsigned comment added by Love me alway (talk • contribs) 03:55, 4 November 2009 (UTC)

Sorry, but Wikipedia is not a venue for original research. — Lomn 04:05, 4 November 2009 (UTC)

Such a compilation may be acceptable on your user page or in a user-space sub-page. See the Help for User Subpages and guidelines for allowable subpages. Again, Wikipedia is not the place to conduct original research; but if you are merely compiling and organizing links to other Wikipedia articles that you find useful, you can put it in your user space. This area has a little less regulation for content, as it is not technically part of the encyclopedia. As far as ownership, all content must be submitted under the Creative Commons and GFDL licenses - keep this in mind. You do not own your user-page or the content you submit to it. Finally, remember that even though Wikipedia offers you some freedom in the user-page space, Wikipedia is not your web host. Our goal is to write an encyclopedia; your user-page space is really supposed to help you (and others) to make contributions to actual encyclopedia articles. Nimur (talk) 05:58, 4 November 2009 (UTC)

Submitting material to Wikipedia is unwise if you wish to be recognized as the author. You could easily be accused later of copying (your own text) from Wikipedia. Cuddlyable3 (talk) 16:16, 4 November 2009 (UTC)

You can generally prove that you were the author of a particular thing by examining the "history" of the item in question. However, there is nothing whatever you can do to prevent someone from changing what you wrote - or copying it - or deleting it - or anything else. The open licensing of Wikipedia not only allows that - it actively encourages it. However, your own "findings" about something are completely unwelcome here. The goal is for all information to be generated in a neutral manner by reference to respected source material. Nothing you think up for yourself is allowed into any Wikipedia article...so what you suggest would likely be vehemently opposed from all sides! SteveBaker (talk) 22:13, 4 November 2009 (UTC)

Name reactions in Chinese Wikipedia

Look at the articles about name reactions in Chinese Wikipedia. Why don't they translate the names into Chinese? --128.232.251.242 (talk) 10:37, 4 November 2009 (UTC)

Chinese is in general iconic rather than sound based. The problem is with us using Chinese designations as they'd see it is us not using the proper icon but just a particular sound. Dmcq (talk) 10:54, 4 November 2009 (UTC)

But almost all the people do have a Chinese name, with almost no exceptions, for instance see zh:Category:Living people. Adolph Wilhelm Hermann Kolbe translates to zh:阿道夫·威廉·赫尔曼·科尔贝 in Chinese. So why don't they translate the name Kolbe in Kolbe electrolysis into Chinese? --128.232.251.242 (talk) 11:12, 4 November 2009 (UTC)

I didn't see any specific guideline there about it. I guess their chemists must just find it easier. You could always ask on a talk page there. Dmcq (talk) 12:33, 4 November 2009 (UTC)

They don't translate the name because it's a proper noun specifically referring to the reaction. If it were also translated it would be a generic adjective of something. It looks odd because of the huge contrast between roman characters, but it's standard convention in most types of math and science to hold the names. Just because it was able to translate "Kolbe" doesn't mean it came out as "Kolbe"; in its eyes it translated "kolbe", which is a very important distinction. This all happens a whole lot in Japanese, too. Why don't we use their characters for their historical persons or theorems? It's "mostly" easier to move into a lettered format than from that into complex characters. I don't know the term of it in traditional Chinese, but it's "Romanji" in Japanese, literally the romanization of the real language so that most anyone in the world can try to pronounce a word. A nod to European influence via early trading routes into the long-established Eastern cultures. ♪ daTheisen(talk) 15:53, 4 November 2009 (UTC)

I think the reason is really because people are lazy and there are many different (conflicting) complex standards for transliterating foreign names. PRC, Hong Kong and Taiwan all have different transliteration schemes with different characters, which editors would need to deal with using templates, which has quite a learning curve. It's nowhere near as simple as romaji for Japanese, and it's further compounded by the great firewall of China (although I heard Wikipedia's been unblocked?). --antilived^{T | C | G} 06:17, 5 November 2009 (UTC)

In fact our own languages reference desk would probably be best at WP:RD/L. My guess is that people read and write about chemistry but names of people and places are things one says. Even so you will quite often see some special name translated by meaning rather than sound into English. Dmcq (talk) 15:42, 4 November 2009 (UTC)

It's a myth that Chinese is iconic rather than sound-based. All languages are phonetic, but not all languages have a phonemic writing system. John Riemann Soong (talk) 16:39, 4 November 2009 (UTC)

All spoken languages are phonetic. Sign languages are not, and it is possible to have an entirely written language which is not simply a representation of a spoken language. In fact, I gather written literary Chinese (Literary Sinitic) is quite close to this [22]. 86.142.224.71 (talk) 18:38, 4 November 2009 (UTC)

Which is what I meant. It can be pronounced very differently in different dialects. Dmcq (talk) 22:27, 4 November 2009 (UTC)

Not only pronounced differently: it is a different language to most (all?) of the 'dialects'. Children who have a mother tongue other than Mandarin (and even those who have Mandarin?) have to learn it in order to write. 86.142.224.71 (talk) 22:37, 4 November 2009 (UTC)

Classical Chinese may be helpful here Nil Einne (talk) 10:01, 5 November 2009 (UTC)

universities

can i known what are the top universities in uk for m pharmacy —Preceding unsigned comment added by Nagtej (talk • contribs) 13:39, 4 November 2009 (UTC)

Sorry, I'm not sure how I can help. The same way that Wikipedia isn't a source or original research, we also can't try to create new ideas using information from Wikipedia. We hold to a standard of neutral point of view in articles, so there would be no way to to make guesses like that even if we thought we should! Good luck... ♪ daTheisen(talk) 15:57, 4 November 2009 (UTC)

The QUB School of Pharmacy has been rated as the top Pharmacy School in the UK in the 'Times Good University Guide 2010' [www.qub.ac.uk/schools/SchoolofPharmacy/dl/] and The University of Nottingham in the 2006 Times Good University Guide [www.nottingham.ac.uk/pharmacy/undergraduates/index.php]. Tracking down the mentioned guide will surely lead to others. 75.41.110.200 (talk) 16:13, 4 November 2009 (UTC)

UCAS (Universities & Colleges Admissions Service) can help you with information on undergraduate degree programmes at UK universities and colleges.Cuddlyable3 (talk) 16:10, 4 November 2009 (UTC)

Yet another best of list at the guardian. --Tagishsimon (talk) 16:14, 4 November 2009 (UTC)

See here for the Times Good University Guide for Pharmacology and Pharmacy. --Tango (talk) 17:53, 4 November 2009 (UTC)

Was the discovery of evolution "inevitable" in the 19th Century? Why

I visited an aquarium last week, and one of the exhibits said that because of changes in scientific thinking the discovery of evolution was "inevitable" in the 19th Century. It mentioned that Charles Darwin and Alfred Wallace discovered it independently, and said that even if they had not seen it the theory's time had come and someone else would have done soon. Is this true, or if it was not for these two discoverers could we still not understand evolution today? If it is true what changes in thinking and previous discoveries made the theory of evolution inevitable? As a side question do you "discover", "invent", or "author" a theory - I don't know quite what to write! -- Q Chris (talk) 15:01, 4 November 2009 (UTC)

It's hard/impossible to speculate whether anything that already happened was "inevitable" but I'm fairly certain that someone else would have struck upon the idea before too long. A lot of the original theory was essentially "Wait a minute... That animal looks a lot like that other animal" and you don't need a rich guy or a traveler to notice that. The Great man theory is probably relevant here, but essentially it's not really possible to factually answer your question. ~ Amory (u • t • c) 15:14, 4 November 2009 (UTC)

Oh, and as for your last question, you can say "constructed" or "formulated." ~ Amory (u • t • c) 15:16, 4 November 2009 (UTC)

It was inevitable if you consider that genetic studies were independent of evolution. While the early studies didn't know anything about genes or DNA, they were tracing patterns of inheritance from parent to child, such as colors of kernels of corn and eye color in mice. Eventually, someone would have to recognize that traits were being passed from parent to child. As soon as someone were to stumble upon mutation, evolution would be evident. -- kainaw™ 15:20, 4 November 2009 (UTC)

The idea of evolution generally was well-known and well-discussed well before Darwin and Wallace. The idea of natural selection being the mechanism of evolution probably would have come out at some point if both of those two had been hit by a train before their time. This distinction is rather important. It is not a matter of saying "this animal looks like this one"—people had already been doing that for a long time, even in the scientific sphere (see, e.g. Erasmus Darwin, Jean-Baptiste Lamarck, and less scientifically, Robert Chambers, etc.).

There were a lot of people thinking along similar lines at the time—it was definitely "in the air". Darwin is especially well-known because he articulated it in a rather careful form, with lots of evidence, and with all the power of his already-established scientific name attached to it. (Wallace was, in this sense, very much at a disadvantage.) He had powerful friends who assured that the theory would be taken seriously and given attention within the scientific community and not dismissed as just a variation on Lamarck or as just political claptrap (Cf. Vestiges of the Natural History of Creation).

As for the distinction between "discoveries", "inventions", "authors"—it's a great question, one that professional historians have actually argued quite a lot about. It depends on your conception of authorship itself, and on your conception of what is to be authored. Are theories hanging out there "in the world", waiting to be discovered? Or is the process of articulating a theory a creative act as well as an objective one? I tend to think the answer is somewhere in between—there is a "core" reality to be "discovered", but the aspects of it that get written about, and the ways in which they are formulated in human language, and made convincing and compelling, are a definitely parts of an authorial intervention—an "invention", one could say. This is much easier to see as time goes on—Darwin's theory of natural selection, as he articulated it, contains quite a bit of "nature" in it, but it is very much a work of the particular man himself, and his formulation of it, his preoccupations, his way of arguing it, all reflect that very strongly. --Mr.98 (talk) 15:28, 4 November 2009 (UTC)

(ec, and now mostly redundant. But I wrote it, so you better read it ;-): "Evolution" was evident quite a while before Darwin and Wallace from looking at fossils. See history of evolutionary thought. Erasmus Darwin described evolution in the late 19th century, and Lamarck formulated his idea of species evolving to better meet environmental conditions in 1809. What Darwin (and Wallace) added was the mechanism of natural selection working on variations of inherited traits, not the idea of evolution itself. --Stephan Schulz (talk) 15:32, 4 November 2009 (UTC)

I would argue that yes, evolution was an inevitable 'discovery'. It's extremely elementary that weak things are removed over time and robust things remain. It applies to everything across the spectrum, from the erosion of mountains, to biological features, to ruling powers. I suppose it appeared when it did as rationality was starting to question the religious hegemony of past centuries, not because the idea itself was necessarily of profound importance. Vranak (talk) 16:09, 4 November 2009 (UTC)

I think you underestimate the difficulty of making the scientific case (ignore the religious stuff for a moment—it mattered for some, not for others). Remember that when Darwin proposed evolution there was no good model for biological heredity at all, a relatively new knowledge of the fossil record, and no consensus over the age of the Earth. This makes making a compelling scientific argument about natural selection rather difficult. If the rate of change is too slow, and the Earth is too young, then it doesn't work. Without a model of heredity that allows for things like mutations, you don't have any way for speciation to take place. These are non-trivial concerns. There were plenty of people before Darwin who waived their hands and said "oh this is a common principle to all things so it applies to humans" (again, see Robert Chambers), but 1. they were more often than not wrong (because there are a lot of candidate "common principles"), and 2. they were totally uncompelling (because just because something works in one arena doesn't mean it works in another). Even in Darwin's case, it was not totally compelling—most scientists did not accept natural selection as the mechanism of evolution until long after he had died and the modern evolutionary synthesis was developed (some 70 years after Origin of Species!). (And this latter point has nothing to do with religion—they accepted evolution in general.) --Mr.98 (talk) 16:32, 4 November 2009 (UTC)

If you read The Origin of Species it's quite clear that Darwin wasn't proposing an original idea. Rather he did a lot of careful synthesis and research in order to champion an idea. The Origin gave a confused set of ideas clarity and made it obvious how and why they had to be true. I think you can divide scientific "discoveries" into three kinds;

1. "wtf is this" discoveries, finding something, such as a fossil or a strange unexpected residue, eg Ardi or teflon
2. "eureka" discoveries, a sudden stroke of genius like the Dirac equation and Archimedes' principle
3. "synthesis" "discoveries" like the theory of evolution or plate tectonics. These are the best and hardest.

In the popular imagination, people think science is largely of the "eureka" type, which are actually probably the rarest. -Craig Pemberton (talk) 16:45, 4 November 2009 (UTC)

I like that classification, and I will make the phrase "wtf discoveries" part of my working vocabulary ;-) --Stephan Schulz (talk) 18:10, 4 November 2009 (UTC)

See Multiple discovery and Stigler's law. Fences&Windows 03:40, 5 November 2009 (UTC)

self-ionisation of glacial acetic acid

How does it compare to water? How does the entropy contribution of the reaction change? What about enthalpy of self-ionisation? John Riemann Soong (talk) 16:37, 4 November 2009 (UTC)

Current and time threshold

I'm trying to design a circuit that activates a transistor when a photodiode has been illuminated at a certain intensity for a certain time, but only when at least a certain current is produced non-stop during that time, e.g. 5µA for 50ms. Essentially I want it to start a "stopwatch" the instant the current rises above 5µA, and reset that stopwatch the instant the current drops below 5µA. If the timer reaches 50ms before it is reset, a monostable LMC555 fires and holds a transistor (logic-level MOSFET or Darlington BJT - I haven't decided yet) high for about half a second. Ideally the entire procedure would be analogue, since I want to keep everything small and simple, and I also want it to use as little power as possible so I can run it off a minimal battery like a button cell. I'd also like to keep it as small as possible physically.

I've brainstormed about this for a while, but I can't figure out any good, simple ways to do it. Any ideas? --Link ^(t•c•m) 16:40, 4 November 2009 (UTC)

reactivity esters v. carboxylic acids

Why are carboxylic acids classified as less reactive than esters? Alkoxides tend to be worse leaving groups than hydroxides, right? (Except methoxide, which has a lower pKa). Alkyl groups tend to be electron donating, right..? (Or do they also delocalise some of the negative charge on the ethoxy ester oxygen?) John Riemann Soong (talk) 16:51, 4 November 2009 (UTC)

How do you mean "less reactive" anyways? In terms of cleaving the C-O bond? Hydroxide is a worse leaving group than any alkoxide, so clearly in terms of -COOR -> -CO + OR if R = alkyl is more favorable than R = H. In other ways; for example in terms of reactivity with bases, carboxylic acids are more reactive. You need to define what reaction you are trying to do! --Jayron32 21:12, 4 November 2009 (UTC)

Acyl substitution, naturally. (Acid-base reactions are trivial...) How is -OH a bad leaving group compared to an alkoxide? The pKa of water is 15.7; the pKa of most alcohols is 16-18. (Save phenols) John Riemann Soong (talk) 21:41, 4 November 2009 (UTC)

Alkoxides are more stable ions because they are "softer"... in other words, there is greater dispersion of electric charge across a larger ion. That makes it more kinetically favorable; i.e. it sticks around longer. There's more going on here than just looking at the pKa, which is basically "H+ affinity" and not much else. Thermodynamically, it is harder to remove a proton from an alcohol than from water (and thus, conversely, it is more energetically favorable to protonate an alkoxide anion than to protonate hydroxide). So, if one considers the controlling factor in the reaction to be "Le Chatelier's principle" ONLY (that is, the protonation of the leaving group driving the equilibrium towards completion), then it would appear that hydroxide would make a better leaving group. However, there are other factors to consider beside that; for the equilibrium constant for the leaving group process (i.e. RCOOR <-> RCO⁺ + ^-OR). The more OR is made, the faster it will be quenched by availible H⁺ ions. The difference in the pKa's is probably not nearly as great as the difference in the K's for that process, for example if R = H vs. R = alkyl. You have a complex mix of processes here, and the kinetics of the slowest step is the driving force here. Protonation of the anion is a relatively fast step, so the difference in the pKa's is unlikely to be a major factor here. --Jayron32 05:58, 5 November 2009 (UTC)

fetus/mother sharing

When a pregnant women has an orgasm does the fetus experience pleasure or the orgasm as well? 71.100.13.177 (talk) 16:58, 4 November 2009 (UTC)

The umbilical cord doesn't contain any nerves, so the fetus couldn't experience the orgasm itself. They might get some of the hormones that are released during orgasm (oxytocin, prolactin and maybe some others), which might give the fetus the same feelings of pleasure and relaxation following the orgasm. --Tango (talk) 17:59, 4 November 2009 (UTC)

The main endogenous opioid associated with orgasm is β-endorphin, which can cross the placental barrier, so it seems plausible that the fetus would experience the opiate-high elements of orgasm, but that's a long way from the full and complex emotional and physical experience. In any case, I seriously doubt that the answer is known. --Sean 18:14, 4 November 2009 (UTC)

Antabus

In the film Skavabölen pojat, the family's father, already becoming slightly alcoholic when his sons are in pre-school age, is shown having taken an Antabus pill to try to cure his alcoholism. He shows his sons his bare stomach, where this Antabus pill has supposedly lodged itself firmly enough to be outwardly visible and tangible. A decade later, desperate to drink more alcohol, he is shown to surgically remove this pill from his stomach, so he can continue drinking without having any nauseous effects. Now I have never had to take Antabus myself, and I hope I never will. So therefore my question is out of scientific curiosity: The film gives the impression that once an Antabus pill is taken, it permanently lodges itself in the person's stomach, never dissolving. This is entirely unlike I have come to understand pills work - they should dissolve within days. How is this? How do Antabus pills work? Are they really permanent or have I just misunderstood the film's hints? JIP | Talk 19:59, 4 November 2009 (UTC)

The Disulfiram article has information about the pharmacology of Antabuse. The effect is most certainly not permanent. The film appears to have taken some liberties with the mechanism of action. --- Medical geneticist (talk) 20:26, 4 November 2009 (UTC)

According to our article, the half life of Antibus (disulfiram) is somewhere around 60-120 hours, and it can have some effect for up to two weeks. Red Act (talk) 20:30, 4 November 2009 (UTC)

Opting out of evolution in biology classes

Currently, many high-school biology classes allow parents to opt their students out of dissections if they are morally or religiously opposed to them. Why isn't a similar system put in place for the teaching of evolution? --J4\/4 <talk> 20:24, 4 November 2009 (UTC)

Is studying evolution banned by any religion? I'm fairly sure actual dissection is banned by the religion itself, not just the parents. Vimescarrot (talk) 20:30, 4 November 2009 (UTC)

In some schools, it is. In my California public high school in the 1990s, you could opt out of the evolution unit if your parents wanted you to. You had to go sit in study hall for those two weeks, or whatever length of time it was, while the rest of us stared at pictures of horses' feet. I'm not sure if anyone in my class did it; if it did, it was only one or two. (It was a very boring unit, incidentally—not nearly as racy as they had let on—but not as boring as being in study hall, probably.) I imagine that this issue, like all U.S. school-curricula issues, varies not only state by state, but probably even school district by school district. --Mr.98 (talk) 20:31, 4 November 2009 (UTC)

There is in the UK. I once helped out on a school trip that involved a visit to a natural history museum and we had to be careful what we said because one of the children wasn't allowed to learn about evolution (there was only one exhibit that we had to gloss over, the rest was pretty safe). --Tango (talk) 20:32, 4 November 2009 (UTC)

Schools are flexible, and should be. As a seven year old in the UK I adamantly came out as an atheist and refused to take part in anything related to Christmas or nativity because I said it was religious propaganda. I recall I was spared learning Carols and poems about Jesus and given parts of Old Possums book of cats to memorise instead. I doubt the school even bothered to check with my parents, and fifteen months later I softened and agreed to play Noah in a play (which didn't bother me because no one actually believes in Noah). I guess in an ideal world children should be able to opt themselves out of anything as soon as they know enough about it to feel they could make a decision. But I am far from sure that parents should be allowed to opt their children out of things, especially not for bad reasons. To really put the cat amongst the pigeons my reading of this as a Christian is that Genesis clearly explains "knowledge of Good and Evil corrupts" which is why I don't want my own children to see explicit violence or nasty but there is no forbidden fruit on a tree of "knowledge of blindingly obvious consensus science" --BozMo talk 20:42, 4 November 2009 (UTC)

IMO all teaching should be done in a neutral manner so there should be no need for anyone to opt out. Knowledge is always good, it is the application of knowledge that can be bad. --Tango (talk) 20:50, 4 November 2009 (UTC)

Not clear what "knowledge" is then, and when it demerges from experience. "Knowledge of how extreme pain feels"? even if you do disagree with Einstein about weapon technology... --BozMo talk 21:04, 4 November 2009 (UTC)

Personally, I'd say that one can be a well educated adult without having engaged in dissections. It takes some effort to get the same insights from books and such, but it is certainly possible. On the other hand, I would say that one's education is grossly deficient if you don't understand the basic principles of evolution and the evidence for it. In my opinion, that's true even if one chooses not to accept evolution as factually true. It would be like not learning the atomic theory of matter, or not learning the structure of the solar system. Sure one can survive without that knowledge, but there is rather something incomplete with an education that skips over such basic issues. So, personally, I would resists efforts to allow students to opt-out of evolution discussions on the grounds that it really deprives the student of an important and basic science understanding. I would also point out that evolution is included on many standardized science tests, including those required for high school graduation in some areas. Dragons flight (talk) 20:52, 4 November 2009 (UTC)

I kind of agree but does that mean I can also force them to learn Shakespeare or force them to learn to swim "one's education is grossly deficient"? I am just not sure I have the right to force it on people... --BozMo talk 21:00, 4 November 2009 (UTC)

You can object to the whole principle of compulsory education if you want, but you won't find many people that agree with you (other than children that hate school!). --Tango (talk) 21:35, 4 November 2009 (UTC)

No I am not amongst these folk Compulsory_education#Criticism but really we are talking compulsory syllabus, not compulsory education. You could drop biology 6 years younger than you were allowed to drop Latin at my school. How much evolution is really core education versus say Shakespeare? Pre genetics the careers advice used to be "if you can do maths and want to, do maths, if you can do maths and want to do science do Physics, if you cannot do maths and want to do science do Chemistry, if you cannot do science but want to do science do biology". Clearly I am outraged at having to do so much Latin, but I don't want biology to become the new Latin either... :) --BozMo talk 22:01, 4 November 2009 (UTC)

I don't see how you could practically skip the evolution section. As somebody said, nothing in biology makes sense except in light of evolution -- what would you do for the rest of the course? Looie496 (talk) 21:50, 4 November 2009 (UTC)

There are two counteracting principles here:

• Firstly, one cannot intelligently criticize something unless you've learned a fair bit about it first. Children of parents who disbelieve in evolution are precisely the ones who NEED to be taught it because they'll never learn it any other way - and they'll be incapable of making their own minds up about it as adults unless they were taught it while their minds were still flexible enough to absorb it. That cuts both ways - I don't think the children of atheists should be able to prevent their kids doing at least a basic comparative religion class. That there are religions is a fact - and understanding a reasonable range of them is well worth-while. So long as the class sticks to the observable facts (in both cases) - there should be no problem.

• However, we have a problem. Kids are only in school for so long - and their capacities for maintaining focus is somewhat limited. So we can't go in and teach them absolutely everything about everything. Some things have to take a higher priority. Fundamentals - math, literacy, language, basic science - all have to have a certain amount of time assigned to them, it's just unavoidable. The amount of time left in the school year after the essentials determines how much exposure to these other topics one gets. It's crucial that they see a little of everything that the world of knowledge has to offer - but spending (say) an entire year on evolution or on comparative religion is far too much.

IMHO, parent's opinions should count for very little indeed. It's flat out not right that a child should be forcably prevented from learning things that their idiot parents failed to grasp. The entire reason that most countries in the world have mandatory education for children is because their parents can't be trusted to do the right thing otherwise. Being able to choose not to have their children learn evolution (or comparative religion) for a few weeks is no more defensible than allowing parents to not have their children be educated at all.

If you allow parents to cherry-pick the courses they want their kids to attend - on religious grounds, or any other grounds for that matter - then pretty soon you're going to have parents who adhere to Sharia law deciding that their female children should not be educated at all past the age of 8. As a nation, we come to a consensus as to what needs to be taught - and everyone should be taught it.

SteveBaker (talk) 22:02, 4 November 2009 (UTC)

Apart from the "as a nation" bit which we are clearly not, I find it hard to disagree with any of this. Up until the child can make an informed refusal they should be taught everything. How much they get taught to make an informed refusal is subjective. --BozMo talk 22:05, 4 November 2009 (UTC)

I'm not aware of any schools in the US that allow you to opt-out of dissection based on religious reasons. Given separation of church and state, it won't be an issue they can make lightly. Most schools either fail the students for that assignment, or make the assignment "free" so there is no grade for it. — The Hand That Feeds You:^Bite 22:22, 4 November 2009 (UTC)

The reason I mentioned it is because it is that way at my (public) school. If a student brought in a signed note from a parent or guardian explaining why dissections are against his/her moral or religious principals, the student would be given an alternate assignment instead. ----J4\/4 <talk> 23:10, 4 November 2009 (UTC)

Where I grew up, one could get out of the 9th grade dissections for any reason whatsoever (not just religious ones). However, one wasn't allowed to opt-out of the dissections in the AP Bio class (typically 12th grade), but then the AP class was optional while the 9th grade class was mandatory. I don't recall what they did about grades in 9th grade, but I don't recall it being a big deal. Dragons flight (talk) 00:33, 5 November 2009 (UTC)

Another question that this raises is, what other subjects could one opt out of? Sex education is the common one—again for moral reasons. Whether that is something that the parent should get to determine or not is a pretty push-button topic. What about select episodes in US history that one doesn't like the presentation of? Certain objectionable books? It's a rather nasty slippery slope to go down—which is why school boards usually set overall standards that are held to, rather that considering it on a case-by-case basis. In any case, there is no quick-and-easy answer, as it is not just a question about evolution, but about the rights of parents v. the rights of states, the goals of compulsory education, and so forth. --Mr.98 (talk) 23:16, 4 November 2009 (UTC)

The objection against dissection runs deeper than simply "religion versus science" and I think it's useful to make note of that. Dissecting animals involving killing things. They're "just" animals, but let's not sugarcoat it. Living things are being killed so kids can look at them. Whether it stems from religious or personal morality, the concept that killing things - any things - is a "bad thing" is extremely ancient and cannot be lightly cast aside. Being able to poke around inside a dead animal to learn anatomy is arguably a good enough justification for doing it, but it's hardly a foregone conclusion - only a tiny percentage of the kids who partake in it will ever make any use of that knowledge ever again. Don't get me wrong; I did it and I had no qualms about it, but I'm honestly not sure how much I actually learned from it (that I didn't concurrently or later learn from models, videos, books, etc.) My later studies - which included studying human bodily remains - didn't hinge upon splitting open a frog and a worm in grade 10 Biology. Matt Deres (talk) 01:50, 5 November 2009 (UTC)

But that's precisely the point. While 99% of students seemed to have gained nothing from it - and some of them were grossed-out, maybe had to run to the bathroom to puke, maybe just couldn't bring themselves to do it, maybe took that cue to become Vegans - the other 1% may have become so inspired by the process that they decided to become surgeons or to enter the field of anatomy, biology, zoology or whatever. The problem is that we don't know who those 1% are until we have them dissect something - and we need that early inspiration in order to get kids to be passionate about something (either way - for or against). The experience of doing it might well turn other kids off - but that's really the point of it. I bet nearly everyone who did that (we dissected earthworms and a cow's eye) remembers that hour of Biology class more vividly than almost any other day of their entire school lives. It's not about teaching anatomy any more than measuring the period of a pendulum in Physics classes is about learning that oh-so-not-vital length-versus-time equation that 99% of them will never use or remember again. It's an experience that no parent is ever likely to teach them...and that's precisely why you shouldn't be able to opt-out. That's also why we need to keep metalwork & woodwork class, art class and music classes, if kids never get to experience those things - how will they know whether they are passionate about them? SteveBaker (talk) 13:07, 5 November 2009 (UTC)

Bears can play hockey?

I watched an interesting video on the internet that shows a team of bears playing hockey. This is the internet so it can quite possibly be fake, but it at least looks real. What do you think? http://video.yahoo.com/network/100284668?v=6255496&l=4418225 if it says "video not available", bypass your cache. -- penubag  (talk) 22:07, 4 November 2009 (UTC)

Yes, according to ABC News, bears playing ice hockey is a standard stunt in the Russian circus.[23] Red Act (talk) 22:30, 4 November 2009 (UTC)

That's crazy. I'd love to go see this in person! -- penubag  (talk) 01:25, 5 November 2009 (UTC)

Bypass your cache?218.25.32.210 (talk) 01:23, 5 November 2009 (UTC)

WP:Bypass your cache -- penubag  (talk) 01:24, 5 November 2009 (UTC)

I remember seeing a hockey-playing bear at a Budapest circus, so it isn't just Russians (or it was a Russian traveling circus) Rmhermen (talk) 03:05, 5 November 2009 (UTC)

Are they playing hockey or just holding sticks and hitting pucks? DRosenbach ^{(Talk | Contribs)} 03:44, 5 November 2009 (UTC)

Are we talking ice hockey then? Nil Einne (talk) 09:26, 5 November 2009 (UTC)

Harmful beryllium oxide in ceramic insolators

I was reading the article about microwave ovens here in Wikipedia, and there was written that some microwave oven magnetrons have ceramic insulators with a piece of harmful beryllium oxide (beryllia) added. How will a person know if the ceramic insulators with a piece of beryllia is a bit broken? Will the microwave oven keep on working if it is a little broken (or a little crushed)? If the ceramic insolator should be a liitle broken or crushed, can the dust from it get inside the cooking chamber (or outside of the microwave oven)?JTimbboy (talk) 22:46, 4 November 2009 (UTC)

The OP probably refers to this text in the article Microwave oven: Some magnetrons have ceramic insulators with a piece of beryllium oxide (beryllia) added—these ceramics often appear somewhat pink or purple-colored. The beryllium in such oxides is a serious chemical hazard if crushed and ingested (eg, inhaling dust). In addition, beryllia is listed as a confirmed human carcinogen by the IARC; therefore, broken ceramic insulators or magnetrons should not be handled. This is obviously only a danger if the microwave oven becomes physically damaged (ie, cracked ceramics) or upon opening and handling the magnetron directly, and as such should not occur during normal usage. Cuddlyable3 (talk) 01:37, 5 November 2009 (UTC)

November 5

A sculptor who works in dark matter

How would such a sculptor go about it? What would the results look like? or, if invisible, is there any way one could perceive the results?

Thanks

Adambrowne666 (talk) 00:08, 5 November 2009 (UTC)

Nobody even knows for sure what dark matter is, so there is no way anyone could make a sculpture out of it. --Tango (talk) 00:17, 5 November 2009 (UTC)

True. Let's play with the idea though, based more on current theories than on what it is for sure. Adambrowne666 (talk) 00:20, 5 November 2009 (UTC)

I think there are two main theories - either it is regular matter that is just too cold to radiate light (MACHOs), in which case it would be sculpted in the same way as any other regular matter, or it is "weakly interacting massive particles" (WIMPs) which means particles which only interact with other matter through gravity and the weak interaction (which is only really significant in radioactivity). Such matter couldn't be sculpted at all, since there would be no way to hold the dark matter together. --Tango (talk) 01:00, 5 November 2009 (UTC)

Were those acronyms intentional? Seems too unlikely to be a mere conincidence... (MACHO and WIMP, fight!) --antilived^{T | C | G} 05:57, 5 November 2009 (UTC)

Most theories of dark matter would have it be more like a gas (weakly interacting) than a solid, in which case there would be nothing to sculpt. Dragons flight (talk) 00:22, 5 November 2009 (UTC)

And with so little interaction with normal matter, dark matter could not be confined in a gas tank, or cut with with a blade. The only way to control it is with gravity. In any case most of the matter on earth does not give off light, and could be considered dark matter. Graeme Bartlett (talk) 00:46, 5 November 2009 (UTC)

Ok, but ferrofluid isliquid, and can be sculpted, in a manner of speaking. Say we use gravity to shape dark matter. What then? Is there any way of showing off our work? Adambrowne666 (talk) 01:01, 5 November 2009 (UTC)

If you want to use gravity to hold it together you would need to work and store it in a zero-gee environment. If the dark matter is just regular matter then it would reflect light so you could show it off in the same way as any other sculpture. If it is just weakly interacting then I don't think there is any way it could be directly seen. --Tango (talk) 01:05, 5 November 2009 (UTC)

Sounds a bit like it would have to be Conceptual art. AlmostReadytoFly (talk) 09:17, 5 November 2009 (UTC)

Yes, probably right, Tango; there's no way it could be directly seen - aside from the twisted gravity field, is there any way its presence and form could be detected by a person in the same room? what equipment would such a person need to perceive the art? Adambrowne666 (talk) 09:46, 5 November 2009 (UTC)

What cognitive changes take place at birth?

There's a lot of controversy about when exactly killing a fetus/baby becomes murder. One common belief is that it's at (or possibly a little after) the moment of birth. This would only make sense if there are significant cognitive changes caused by being born. I wouldn't find it at all surprising, but it seems strange that I've never heard anything about it one way or another. Is it just impossible to test? If not, what changes take place? Is it generally considered by people in that field to be something necessary for sentience? — DanielLC 00:09, 5 November 2009 (UTC)

I don't think there are any significant cognitive changes that abruptly occur at birth. However, at birth the baby goes from receiving nutrition and oxygen through the umbilical cord to breathing independently and requiring oral food. I know some people place special significance on that first breath, and on the independence from the systems of the mother. I don't think many people worry about sentience per se. Dragons flight (talk) 00:18, 5 November 2009 (UTC)

If it were so, babies born by caesarean section would not be sentient. There is no sharp dividing line: babies born a little before 22 weeks have lived to be sentient, even though there are several important developments in the body and brain between even 34 weeks and the 'mature' 37 weeks. Really, how sentient do you consider a 4 week old baby? Does it have enough experience to understand the world well enough to be considered sentient? Time was, doctors regularly performed surgery on babies and little children without anaesthetic on the basis that they weren't mature enough to really feel pain: they were just reacting instinctively. We now know this is bunk (I know a few older ex-nurses who still go pale at the memory, horrified at what they had been doing once the evidence came in). I don't think there is consensus on a stage of development at which sufficient sentience has developed that the being can feel pain, and doctors carrying out pre-birth procedures have to balance many factors and possible outcomes when deciding what to do. Of course, they may be carrying out these procedures on babies who in other circumstances would be classified only as foetuses.

But given we do not generally consider it murder to kill non-human animals, despite the increasing evidence (staring any observant human in the face) that many species are self-aware and really do suffer when in pain (possible definitions of sentience), I don't think it would really sway anyone. After all, we generally consider it far worse to kill a month-old child than a 5-year-old chimp, even if the chimp can demonstrate its sentience much more fully than the child. 86.142.224.71 (talk) 00:36, 5 November 2009 (UTC)

And there is also the class of the severely retarded or mentally disabled who never pass into a "too little sentience, OK to kill" category (other than brain death). --Mr.98 (talk) 01:07, 5 November 2009 (UTC)

Here you're confounding sentience with cognitive power. They're quite different conceptually. Sentience is the capacity to experience qualia. I see no reason to think that the severely mentally disabled are less sentient than the rest of us. Of course, by the very nature of qualia, we can never really know, one way or another — see solipsism and animism for two opposite conclusions on the question, neither of which is really susceptible to scientific inquiry. --Trovatore (talk) 04:41, 5 November 2009 (UTC)

My belief is that people define words like "life" and "murder" in such a way as to support the rules they want people to follow -- that is, people start with the conclusions, and then work out the premises that are needed to derive those conclusions. Looie496 (talk) 02:30, 5 November 2009 (UTC)

I'd argue that the initial assertion is not accurate. I don't know of anyone or any culture who believes killing a baby in utero a week before it is due would not be murder. Even the most ardent pro choice supporters I know would not argue it is fine to kill a baby just before it is born. A far more commenly held belief in the past was that the quickening was an indicaton of when a foetus became a real person with a soul, there fore capable of being murdered. Vespine (talk) 04:18, 5 November 2009 (UTC)

According to Late-term abortion#Legal restrictions on later abortion, in 54 of the 152 most populous nations, abortion is legal at any stage. — DanielLC 05:48, 5 November 2009 (UTC)

I don't mean the process of birth itself. There is are a lot more sensations when you're born. Things actually happen. Before you're born, there's no point in having any significant brain activity. By the way, I was reading the abortion page and it said that there's some controversy that fetuses might feel pain. This seems rather silly, as they must be sentient to feel pain, and if they are, it's bad to kill them because it's murder. Is the idea that they're like animals for a period, and they have sentience, but no right to life? — DanielLC 05:48, 5 November 2009 (UTC)

Yes. And babies do have significant brain activity before birth and it may be meaningful and they feel pain by most definitions. It's all about definitions really so people who work in words feel okay about it as we have no objective way of measuring sentience or pain and there is no objective reason for them to mean anything anyway, they are not like the amount of energy one can get from a lump of coal or anything like that. Dmcq (talk) 12:23, 5 November 2009 (UTC)

Maximum rate of a energy delivered for a given voltage

I am trying to understand if, given a voltage and a duration, whether it is possible to calculate the maximum amount of electrical energy that can be delivered. To put this in context I am trying to judge the maximum amount of energy it might take to recharge this car given just the voltage and the duration of energy delivery (100 volts - 180 minutes, 200 volts - 100 minutes). I understand that the voltage does not have an exact correlation with how much energy is drawn (my kettle draws 2kwh, and my phone charger much less, even though they are both plugged into a 240v socket), but I want to understand whether there is a maximum rate of energy transfer for a given voltage (or do other things, current?, come into play). Sorry, electricity has always been a big blind spot for me. Any help appreciated. BurningFridge (talk) 00:30, 5 November 2009 (UTC)

See the article on Electric power. In summary (and ignoring power factor) the energy transfer is a function of voltage, current and time. Power (watts) = voltage (volts) x current (amps); energy (joules) = power (watts) x time (seconds). Thus for any given voltage, the maximum energy transfer is a function of the current. In Australia, normal household power outlets are rated at a maximum 10A, although you can get 15A sockets. Mitch Ames (talk) 01:01, 5 November 2009 (UTC)

The likely reason for the disparity (twice the voltage but not half the time) is likely to be to do with the need to limit battery overheating and perhaps also due to inefficiencies through the charging circuit which may worsen as the voltage gets bigger. The physics of recharging batteries is rather complicated. SteveBaker (talk) 01:14, 5 November 2009 (UTC)

Some people find the Hydraulic analogy helps understanding of electricity. The difference between the OP's kettle and phone charger is that the kettle has much lower resistance R (ohms) than the charger. The power taken from the 240V supply is inversely proportional to R so the kettle takes the greater power. (We can calculate the kettle resistance R = 240 x 240 / 2000 = 28.8 ohm.) In principle, from a given voltage one can draw any power by connecting a load of appropriate R. In practice the power delivery is stopped if current I = 240 / R (amps) exceeds the current rating in amps of the fuse. In order to calculate the energy (joules) = power (watts) x time (seconds) for charging the car one needs to know the current drawn from the supply during the charge cycle. Cuddlyable3 (talk) 01:28, 5 November 2009 (UTC)

Indeed, that's true. But it doesn't help much because those car chargers that attempt to charge as quickly as possible don't draw (or supply) continuous amounts of constant current - they have to monitor battery temperature and voltage and vary the amount of current as the batteries are charged in order to prolong their life while minimizing the recharge time. Therefore the actual recharge time will depend on the ambient temperature and the amount of ventilation keeping the batteries cool. It's not easy to calculate without understanding the details of what the charger is doing, how the battery temperature changes, how heat is lost from the battery compartment, etc. SteveBaker (talk) 12:50, 5 November 2009 (UTC)

Flame tests

Will metal ions with different charges (i.e. Fe3+ and Fe2+) produce different colors in flame tests? 76.204.127.175 (talk) 03:53, 5 November 2009 (UTC)

That's a good question. If you haven't already, see emission spectrum. In this situation, it might be helpful to imagine a Bohr model. Under controlled circumstances, we should say that the tempurature is the same for both tests, because varying temperatures can effect the color. Fe+2 is the ion of iron, with 3 energy levels. When excited, we could say that the electrons jump up 3 energy levels, then fall to their original orbital energy level, releasing a photon of light. This is complexely measured in an emission spectrum.

Let's say that for some reason, an electron was taken from the atom of iron, making it Fe+3. If this was able to be maintained, (it would be somewhat difficult to keep the unstable Fe+3 from reacting, unless in a container of inert gas) and it was excited, the electrons would only manage to jump up 2 energy levels. To the naked eye, one might not be able to distinguish different colors, but the emission spectrum would be the tell-all. It would be slightly different than a Fe+2 ion. If you have any questions, ask here or on my talk page :). Letter ⁷ _{it's the best letter :)} 13:51, 5 November 2009 (UTC)

What is the capacitance of a black hole?

The article "Detecting Energy Emissions from a Rotating Black Hole" at [24] (free subscription required to view) makes the statement in passing that the capacitance of a black hole C = 1/M (approximately). I guess these are in natural units. Does anyone happen to know where this relationship is derived or explained, and what the units are? The Wikipedia article on natural units [25] doesn't define capacitance or voltage.

Trevor Turton —Preceding unsigned comment added by Tijaska (talk • contribs) 04:17, 5 November 2009 (UTC)

cosmatics

How cosmatics are manufactured, tell me complete procedure —Preceding unsigned comment added by 119.152.59.27 (talk) 06:36, 5 November 2009 (UTC)

_{I have slightly reformatted your question to make it easier to read. Richard Avery (talk) 08:30, 5 November 2009 (UTC)}

What kind of cosmetics? There are lots of different types. AlmostReadytoFly (talk) 09:12, 5 November 2009 (UTC)

Insolation

How to find solar insolation patterns at various points in the jupiter's atmosphere. A comparison with earth is needed —Preceding unsigned comment added by 220.225.125.246 (talk) 09:16, 5 November 2009 (UTC)

Figuring out the insolation at the top of the atmosphere is easy. It looks like all the trigonometry is worked out in the insolation article, whereas the parameters of Jupiter orbit are given, not surprisingly, in the Jupiter (planet) article. Now, the insolation within the atmosphere is very much more tricky. Strictly speaking, you need to model the absorption and the scattering of light at every position at every wavelength into every direction. This requires a full 3D radiation transfer model. As Gandalf said, "this foe is beyond any of you..." --Dr Dima (talk) 10:32, 5 November 2009 (UTC)

Properties of alcohols

what are he properties for the following alcohols and their chemical formulae:

1. DL-2-pentanol
2. pentan-1-0l
3. octanol-1-0l
4. ethanol
5. butan-1-ol
6. n-porpyl

send to email address removed —Preceding unsigned comment added by 120.18.247.221 (talk) 11:40, 5 November 2009 (UTC)

Wikipedia gets copied mercilessly across the internet. It's a bad idea to put your email address on this website, as it will likely attract much more spam than you want. Falconus^{p t c} 12:39, 5 November 2009 (UTC)

We do not answer questions by email - you have to return here to find responses - and we remove people's email addresses if they provide them. We have articles on pentanol, octanol, ethanol, butanol and propanol which (I believe) will answer all of your questions. SteveBaker (talk) 12:42, 5 November 2009 (UTC)

(edit conflict)

1. See Amyl alcohol
2. See Amyl alcohol
3. See octanol
4. See ethanol
5. See butanol
6. propyl?

These pages generally give the formulae and properties. AlmostReadytoFly (talk) 12:49, 5 November 2009 (UTC)