Complex Structure

Traditionally, the location of lightning strike points has been determined by using the rolling sphere method, but recently the collection volume method (CVM) has also been proposed for the placement of air terminals on complex structures. Both these methods are empirical in nature and a more advanced model based on physics of discharges is needed to improve the state of affairs. This model is used to evaluate the striking distance from corners and air terminals on actual buildings and the results are qualitatively compared with the predictions of the rolling sphere method and the CVM. The results show that the striking distance not only depends upon the prospective return stroke current and the geometry of the building, but also on the lateral position of the downward leader with respect to the strike point. A further analysis is performed to qualitatively compare the lightning attraction zones obtained with the CVM and the leader inception zones obtained for a building with and without air terminals. The obtained results suggest that the collection volume concept overestimates the protection areas of air terminals placed on complex structures, bringing serious doubts on the validity of this method.

Six lexical decision experiments were conducted to examine the influence of complex structure on the processing speed of English compounds. All experiments revealed that semantically transparent compounds (eg, rosebud) were processed more quickly than matched monomorphemic words (eg, giraffe). Opaque compounds (eg, hogwash) were also processed more quickly than monomorphemic words. However, when the experimental materials and/or procedure encouraged decomposition/integration, this advantage ...

When the development of gap models began about three decades ago, they became a new category of forest productivity models. Compared with traditional growth and yield models, which aim at deriving empirical relationships that best fit data, gap models use semi-theoretical relationships to simulate biotic and abiotic processes in forest stands, including the effects of photosynthetic active radiation interception, site fertility, temperature and soil moisture on tree growth and seedling establishment. While growth and yield models are appropriate to predict short-term stemwood production, gap models may be used to predict the natural course of species replacement for several generations. Because of the poor availability of historical data and knowledge on species-specific allometric relationships, species replacement and death rate, it has seldom been possible to develop and evaluate the most representative algorithms to predict growth and mortality with a high degree of accuracy. For this reason, the developers of gap models focused more on developing simulation tools to improve the understanding of forest succession than predicting growth and yield accurately.

Axial X-ray computed tomography CT scanning provides a convenient means of recording the three-dimensional form of soil structure. The technique has been used for nearly two decades, but initial development has concentrated on qualitative description of images. More recently, increasing effort has been put into quantifying the geometry and topology of macropores likely to contribute to preferential flow in soils.

The histone acetylation of post-translational modification can be highly dynamic and play a crucial role in regulating cellular proliferation, survival, differentiation and motility. Of the enzymes that mediate post-translation modifications, the GCN5 of the histone acetyltransferase (HAT) proteins family that add acetyl groups to target lysine residues within histones, has been most extensively studied. According to the mechanism studies of GCN5 related proteins, two key processes, deprotonation and acetylation, must be involved. However, as a fundamental issue, the structure of hGCN5/AcCoA/pH3 remains elusive. Although biological experiments have proved that GCN5 mediates the acetylation process through the sequential mechanism pathway, a dynamic view of the catalytic process and the molecular basis for hGCN5/AcCoA/pH3 are still not available and none of theoretical studies has been reported to other related enzymes in HAT family. To explore the molecular basis for the catalytic mechanism, computational approaches including molecular modeling, molecular dynamic (MD) simulation and quantum mechanics/molecular mechanics (QM/MM) simulation were carried out. The initial hGCN5/ AcCoA/pH3 complex structure was modeled and a reasonable snapshot was extracted from the trajectory of a 20 ns MD simulation, with considering post-MD analysis and reported experimental results. Those residues playing crucial roles in binding affinity and acetylation reaction were comprehensively investigated. It demonstrated Glu80 acted as the general base for deprotonation of Lys171 from H3. Furthermore, the two-dimensional QM/MM potential energy surface was employed to study the sequential pathway acetylation mechanism. Energy barriers of addition-elimination reaction in acetylation obtained from QM/MM calculation indicated the point of the intermediate ternary complex. Our study may provide insights into the detailed mechanism for acetylation reaction of GCN5, and has important implications for the discovery of regulators against GCN5 enzymes and related HAT family enzymes.

Formation of DNA complexes with Langmuir monolayers of cationic lipid octadecylamine (ODA) and new amphiphilic polycation poly-4-vinylpyridine with 16% cetylpyridinium groups (PVP-16) on the surface of native DNA aqueous solution with low ionic strength has been studied. AFM topographic images of DNA/ODA and DNA/PVP-16 complex Langmuir-Blodgett films deposited on the mica substrates were obtained. The complex structures and individual DNA molecules on the amphiphile monolayer surface were observed. The characteristic extended net-like structures and quasi-circular toroidal condensed conformations of the planar DNA complexes were formed in dependence on the polycationic amphiphile monolayer state during the DNA binding. The data obtained give evidence for the effectiveness of monolayer techniques for investigation the mechanisms of DNA complexation with amphiphilic mono-and polycations and demonstrate its perspectives for creation of supramolecular planar DNA-based selforganized nanostructures with nanoscale structural ordering.

Dietary carbohydrates are a group of chemically defined substances with a range of physical and physiological properties and health benefits. As with other macronutrients, the primary classification of dietary carbohydrate is based on chemistry, that is character of individual monomers, degree of polymerization (DP) and type of linkage (a or b), as agreed at the Food and Agriculture Organization/World Health Organization Expert Consultation in 1997. This divides carbohydrates into three main groups, sugars (DP 1-2), oligosaccharides (short-chain carbohydrates) (DP 3-9) and polysaccharides (DPX10). Within this classification, a number of terms are used such as mono-and disaccharides, polyols, oligosaccharides, starch, modified starch, non-starch polysaccharides, total carbohydrate, sugars, etc. While effects of carbohydrates are ultimately related to their primary chemistry, they are modified by their physical properties. These include water solubility, hydration, gel formation, crystalline state, association with other molecules such as protein, lipid and divalent cations and aggregation into complex structures in cell walls and other specialized plant tissues. A classification based on chemistry is essential for a system of measurement, predication of properties and estimation of intakes, but does not allow a simple translation into nutritional effects since each class of carbohydrate has overlapping physiological properties and effects on health. This dichotomy has led to the use of a number of terms to describe carbohydrate in foods, for example intrinsic and extrinsic sugars, prebiotic, resistant starch, dietary fibre, available and unavailable carbohydrate, complex carbohydrate, glycaemic and whole grain. This paper reviews these terms and suggests that some are more useful than others. A clearer understanding of what is meant by any particular word used to describe carbohydrate is essential to progress in translating the growing knowledge of the physiological properties of carbohydrate into public health messages.

The potential of Polarimetric SAR Interferometry (Pol-InSAR) lies in the 3-dimensional resolution of different scattering processes. This proves especially useful for the interpretation of volume scatterers - such as forests - and makes physical parameter extraction possible. Due to the complex structure of forests, the interpretation of Pol-InSAR data is not straight forward, but requires the consideration of a scattering

We analyze the geometrical structure of the astonishing Nasca geoglyphs in terms of their fractal dimension with the idea of dating these manifestations of human cultural engagements in relation to one another. Our findings suggest that the first delineated images consist of straight, parallel lines and that having sophisticated their abilities, Nasca artist moved on to the design of more complex structures.

Retinal blood vessel assessment plays an important role in the diagnosis of ophthalmic pathologies. The use of digital images for this purpose enables the application of a computerized approach and has fostered the development of multiple methods for automated vascular tree segmentation. Metrics based on contingency tables for binary classification have been widely used for evaluating the performance of these algorithms. Metrics from this family are based on the measurement of a success or failure rate in the detected pixels, obtained by means of pixel-to-pixel comparison between the automated segmentation and a manually-labeled reference image. Therefore, vessel pixels are not considered as a part of a vascular structure with specific features. This paper contributes a function for the evaluation of global quality in retinal vessel segmentations. This function is based on the characterization of vascular structures as connected segments with measurable area and length. Thus, its design is meant to be sensitive to anatomical vascularity features. Comparison of results between the proposed function and other general quality evaluation functions shows that this proposal renders a high matching degree with human quality perception. Therefore, it can be used to enhance quality evaluation in retinal vessel segmentations, supplementing the existing functions. On the other hand, from a general point of view, the applied concept of measuring descriptive properties may be used to design specialized functions aimed at segmentation quality evaluation in other complex structures.

We study geometric quantization of moduli spaces of vector bundles on an algebraic curve X, and its relation to theta functions. In limits when the complex structure of X degenerates, we describe vector spaces of distributions with Verlinde dimension, associated to the quantization of some of these moduli spaces in real polarizations. We show that special bases on these spaces, defined using a trinion decomposition of X, are related by modular transformation matrices for characters of affine Lie algebras, which appear naturally in the Blattner-Kostant-Sternberg (BKS) pairing for different quantizations of the moduli space.

The problem of variable selection in neural network regression models with dependent data is considered. In this framework, a test procedure based on the introduction of a measure for the variable relevance to the model is discussed. The main di culty in using this procedure is related to the asymptotic distribution of the test statistic which is not one of the familiar tabulated distributions. Moreover, it depends on matrices which are very di cult to estimate because of their complex structure. To overcome these analytical issues and to get a consistent approximation for the sampling distribution of the statistic involved, a subsampling scheme is proposed. The procedure, which takes explicitly into account the dependence structure of the data, will be justiÿed from an asymptotic point of view and evaluated in ÿnite samples by a small Monte Carlo study.

This paper presents the analysis of the evolution of public websites in the Republic of Bolivia. It shows the changes observed in the design and implementation of 34 private and government websites, how these changes have taken place and how design and usability factors where influenced when implementing this changes. The study puts in evidence the changes in website designing, from simple low-structured content to complex structured content. The article shows also the absence of elicited good practice guides for websites designing and development in Bolivia, although it reports the improvement in Bolivian web design and tries to identify the leading factors of these results. Despite of the relative low developed Internet capacity in Bolivia, the technical level of web developing is near to the observed in more developed countries, but usually without taking care of accessibility and usability issues.

Functional morphology of the calcareous test of Echinus esculentus was investigated by parametric finite element analysis, an engineering technique developed for numerical analysis of the behaviour of complex structures responding to external forces. Finite element models of the test were generated by methods of Computer Aided Geometric Design (CAGD) to calculate the mechanical responses to different types of loading. The load cases included vertical, concentrated load at the apex, vertical, distributed load on the upper third of the test, internal pressure and tensile forces as introduced into the test by tube feet activity. The objectives were the shape of the test, the distribution of material and the alternating zones of porous and non-porous plates within the test.-Echinoid tests resist external loading without showing any specific points of failure. The thickened margins of the periproct and peristome apertures account for load-bearing capacity as well as the thickened meridional structures which carry a greater portion of stress than the thinner parts of the test. Distribution of material is not a response to concentrated loads on the apex nor to self-weight. Taken strictly, echinoid tests are not thin (or membrane) shells. Under loading, bending moments occur which influence the stress state in the entire test. The pneu hypothesis could not be confirmed. Adaptation of the test shape or of the distribution of material as a response to internal pressure does not exist. Tests of regular echinoids are especially well adapted to the mechanical activity of the ambulacral tube feet, i.e. the shape of the test, its flattening towards the substrate, the outward bulge of the ambulacra and the differential distribution of material within the test.& b d y :

In this work, coincidence summing correction factors have been measured for 133 Ba, 152 Eu and 88 Y point sources with a 50% relative efficiency p-type detector and a 25% relative efficiency n-type detector in two close-to-detector measurement geometries. The experimental data for 133 Ba and 152 Eu and the results obtained with the GESPECOR software reveal a complex structure of the conventional dead layer of the p-type detector. The high value of the coincidence summing correction factor for the 511 keV peak of 88 Y, in agreement with the values computed by GESPECOR, in this case cautions against the application of the semiempirical method for evaluating coincidence summing effects.

In recent years there has been an increase in the general public awareness of the ethical aspects of technology. The attention given by the media to computer-related disasters in technical systems such as the explosion of the Ariane 5 rocket in 1996 and the Therac-25 computerized radiation machine overdoses has stimulated interest in Computer Ethics.

In this work, supersonic hydrogen combustion in the Hyshot II scramjet engine is investigated. In particular, fundamental physics of mixing, combustion and vorticity generation as well as the interaction between shock waves, boundary layer and heat release are analyzed by means of 3D Large Eddy Simulations (LES) using detailed chemistry. Results show very complex structures due to the interaction between the four sonic H 2 crossflow injections and the airstream flowing at M ¼ 2.79. A bow shock forms ahead of each H 2 injector: the interaction between bow shocks and boundary layers leads to separation zones where H 2 recirculates. In these recirculation zones, OH radicals are produced, indicating that a flame already starts upstream of the injectors and downstream of the flow separation. The formation of barrel shocks due to the H 2 expansion and recompressions is also predicted. Comparison of pressure distribution along the wall centreline at 1.3 ms shows agreement with experimental results, mostly in the first part of the combustor,

The mobile ecosystem is characterized by a large and complex network of companies interacting with each other, directly and indirectly, to provide a broad array of mobile products and services to end-customers. With the convergence of enabling technologies, the complexity of the mobile ecosystem is increasing multifold as new actors are emerging, new relations are formed, and the traditional distribution of power is shifted. Drawing on theories of network science, complex systems, interfirm relationships, and the creative art and science of visualization, this paper identifies key players and maps the complex structure and dynamics of nearly 7000 global companies and over 18,000 relationships in the converging mobile ecosystem. Our approach enables decision makers to (i) visually explore the complexity of interfirm relations in the mobile ecosystem, (ii) discover the relation between current and emerging segments, (iii) determine the impact of convergence on ecosystem structure, (iv) understand a firm's competitive position, and (v) identify interfirm relation patterns that may influence their choice of innovation strategy or business models.

The highly hydrophobic fluorophore Laurdan (6-dodecanoyl-2-(dimethylaminonaphthalene)) has been widely used as a fluorescent probe to monitor lipid membranes. Actually, it monitors the structure and polarity of the bilayer surface, where its fluorescent moiety is supposed to reside. The present paper discusses the high sensitivity of Laurdan fluorescence through the decomposition of its emission spectrum into two Gaussian bands, which correspond to emissions from two different excited states, one more solvent relaxed than the other. It will be shown that the analysis of the area fraction of each band is more sensitive to bilayer structural changes than the largely used parameter called Generalized Polarization, possibly because the latter does not completely separate the fluorescence emission from the two different excited states of Laurdan. Moreover, it will be shown that this decomposition should be done with the spectrum as a function of energy, and not wavelength. Due to the presence of the two emission bands in Laurdan spectrum, fluorescence anisotropy should be measured around 480 nm, to be able to monitor the fluorescence emission from one excited state only, the solvent relaxed state. Laurdan will be used to monitor the complex structure of the anionic phospholipid DMPG (dimyristoyl phosphatidylglycerol) at different ionic strengths, and the alterations caused on gel and fluid membranes due to the interaction of cationic peptides and cholesterol. Analyzing both the emission spectrum decomposition and anisotropy it was possible to distinguish between effects on the packing and on the hydration of the lipid membrane surface. It could be clearly detected that a more potent analog of the melanotropic hormone α-MSH (Ac-Ser 1 -Tyr 2 -Ser 3 -Met 4 -Glu 5 -His 6 -Phe 7 -Arg 8 -Trp 9 -Gly 10 -Lys 11 -Pro 12 -Val 13 -NH 2 ) was more effective in rigidifying the bilayer surface of fluid membranes than the hormone, though the hormone significantly decreases the bilayer surface hydration.

The aim is: how cities could fit the quality idea, the urban lifestyle that is our welfare dream? But what is our dream? A city that reflects, as in a mirror, our identity. We know very well what we want: beauty, harmony, naturality and safety. For gaining them, we need to define "how" to satisfy these needs. 1. We look for naturality, but in the same time we love sophisticated answers to our needs. And naturality that fits human needs is a result of high quality design and management approach. 2. We are looking for beauty and harmony, but we are loosing these qualities, that we had in the past, in these convulsed improving density cities that satisfies only pre-defined and functionally optimized necessities 3. But first of all we need clarity and safety; and we discovered that also what appeared as impossible and unthinkable catastrophe was happened. And Safety can be realized only if each people can share a process of evolutionary conscience. The complex structure of a c...

The feeding ecology and trophic organization of 32 fish species found in an highly impacted waters from four sites of the eastern Johor Strait, Singapore has been studied. Among the wide variety of prey consumed, calanoid copepod (46.9% domination) was the most important dietary component of fishes in this ecosystem. In general, fishes show a narrow range in adaptive radiation of feeding habits, with only three main guilds identified. Spatially, a more complex guild was recorded for the habitat with more complex structure, although the number of guilds was consistent at three to four guilds. Seasonally, a change of guild organization was observed. Many fish species placed in one guild might be classified in another guild during a different season. This information facilitates the examination of complex associations of fishes and identifies groups of species that use similar resources within a specific community and can serve as a reference for feeding ecology of fishes in highly impacted tropical habitats.

The static dielectric constant and viscosity of the binary mixtures of glycerol (Gly) with N,Ndimethylformamide (DMF) and N,N-dimethylacetamide (DMA) were measured over the entire composition range at temperatures 288.15, 303.15, 318.15 and 333.15 K. The concentration dependent non-linear behaviour of the measured thermodynamical parameters revealed the formation of hydrogen bond interactions between glycerol and amide molecules with a variety of complexes. The excess dielectric constant and excess viscosity were determined and analyzed for the confirmation of the composition of dominant complex species. Results inferred that the dielectric polarization in both the Gly-DMF and Gly-DMA mixtures is governed by 1:1 complex species with enhanced dipolar ordering at all the investigated temperatures. The complex species of 3Gly:DMF and 2Gly:DMA facilitates the viscous flow process in Gly-DMF and Gly-DMA mixtures, respectively and the density of these species is strongly influenced by the change in temperature. Arrhenius type behaviour of viscosity against the reciprocal of temperature was used to determine the apparent activation energy of the viscous flow. The electric-field-induced increment of the Helmholtz free energy and the entropy were determined from the temperature dependence of the static dielectric constant and its derivative of the binary mixtures. Results were discussed to assess the volume effect of DMF and DMA molecules on hydrogen bonding interactions with glycerol molecules in order to confirm the structural conformations of these mixed solvents.

U-Pb, Ar/ 39 Ar, and Sm-Nd geochronological results from isolated basement exposures and drill-core samples in the Kalahari Desert, Botswana constrain the distribution and temporal evolution of Proterozoic crustal provinces in this part of Africa. There is evidence that a buried, northeast-trending Mesoproterozoic orogen lies outboard of older crustal provinces in eastern Botswana. The subsurface part of this orogen includes a granitic-gneissic terrain in northern Botswana that records plutonism and amphibolite-grade deformation between 1.2 and 1.1 Ga. Limited exposures of bimodal volcanic rocks in the Kalahari Desert are interpreted to represent extensional magmatism superimposed on the buried Mesoproterozoic belt. Previously published geochronological data and new U-Pb zircon crystallization ages presented here indicate that these volcanic rocks and associated subvolcanic intrusions were emplaced at 1.1 Ga, as part of the widespread Umkondo within-plate igneous province. Geophysical data, sparse outcrops, drill-core samples, and reconnaissance 40 Ar/ 39 Ar geochronology show the buried Mesoproterozoic orogen to be separated from the Congo craton by a continuation of the Neoproterozoic-Lower Paleozoic Damara belt exposed in Namibia. Limited outcrops of 2.05 Ga augen gneiss within a largely buried basement massif in northwestern Botswana are inferred to be part of a Paleoproterozoic crustal province developed along the southern margin of the Congo craton. The massif was intruded by granites at 1.02-1.00 Ga, but the extent and tectonic significance of this plutonism are uncertain. Deformed granite in the subsurface extension of the Damara belt has a protolith crystallization age of 0.72 Ga. Complex structural patterns in northwestern Botswana are inferred to reflect heterogeneous Damaran deformation around a promontory extending from the southern margin of the Congo craton.

Hundreds of different types of coatings are used to protect a variety of structural engineering materials from corrosion, wear, and erosion, and to provide lubrication and thermal insulation. Of all these, thermal barrier coatings (TBCs) have the most complex structure and must operate in the most demanding high-temperature environment of aircraft and industrial gas-turbine engines. TBCs, which comprise metal and ceramic multilayers, insulate turbine and combustor engine components from the hot gas stream, and improve the durability and energy efficiency of these engines. Improvements in TBCs will require a better understanding of the complex changes in their structure and properties that occur under operating conditions that lead to their failure. The structure, properties, and failure mechanisms of TBCs are herein reviewed, together with a discussion of current limitations and future opportunities.

The development process of hypermedia and web systems poses very specific problems that do not appear in other software applications, such as the need for mechanisms to model sophisticated navigational structures, interactive behaviors, interfaces with external applications, security constraints and multimedia compositions. Even though experience, modelling skills and abstractions can be borrowed from existing software design methods, such as objectoriented modelling, hypermedia developers need specific mechanisms to analyze and design using entities that belong to the hypermedia domain (such as nodes, links, anchors and space and time-based relationships). Moreover, hypermedia methods should provide mechanisms to deal with all the aforementioned features in a progressive and integrated way. In this paper, we present the Ariadne Development Method (ADM), a software engineering method that proposes a systematic, flexible, integrative and platform-independent process to specify and evaluate hypermedia and web applications. ADM has been shown particularly useful in complex systems involving a huge number of users with different abilities to access information, with a complex structure where a huge number of nodes have to be organized in a clear way to produce specifications that are discussed by people with an heterogeneous background. This is the case of ARCE, a Latin American project where 21 countries are cooperating to produce a web platform to improve assistance in disaster mitigation situations. r

Over the last three decades the first-order correlation in morphology and orientation of seamount trails has been called upon to support the concept of a ''fixed'' Pacific hot spot frame of reference and to explain the Hawaii-Emperor bend (HEB) by a dramatic change in Pacific plate motion. In this paper, however, we present 40 Ar/ 39 Ar ages for the Gilbert Ridge and Tokelau Seamounts (Pacific) that show similar changes or bends in their orientation, but at different geological times, up to 20 Myr earlier than the HEB. Changes in Pacific plate motion alone cannot explain these observations, because these asynchronous bends should have been reflected in the morphology of each of these seamount trails. Together with the lack of (linear) age progressions and inconsistent apparent local plate velocities of 131 and 87 mm/yr, we rule out a fixed hot spot origin for the Gilbert Ridge and Tokelau seamount trails. Instead we invoke secondary or alternate processes to explain the complex age systematics and morphologies in these seamount trails. We propose here that the HEB-type bends in these seamount trails were likely formed by short-term ''jerk-like'' plate extensions in the studied southwestern region of the Pacific plate, reactivating a preconditioned lithosphere that can be characterized by a complex structure and precursory magmatic impingements. The remarkable differences observed in these colinear seamount trails fundamentally question the existence of HEB-type bends in the formation of Pacific volcanic lineaments. They also show us that applying geometric and morphologic observations alone is insufficient in constraining past plate motions. Nevertheless, the need and search for alternate volcano-tectonic mechanisms offer opportunities to better understand intraplate volcanism in general.

The modification of free amino groups on proteins, lipids, and nucleic acids by non-enzymatic glycosylation produce a variety of complex structures named advanced glycation end products (AGEs). Glycation of these molecules participate in the development of diabetic complications and related diseases. Diabetes mellitus is characterized by short-term metabolic changes in lipid and protein metabolism, and long-term irreversible changes in vascular and connective tissue. AGEs are directly implicated in the development of chronic complications in diabetes such as nephropathy, rethinopathy, neuropathy, and other related diseases such as atherosclerosis, heart disease, stroke, and peripheral vascular disease. In this review, we aim to explain how glycation occurs in different molecules and what the pathological consequence of AGE formation in diabetes mellitus and other diseases are.

In this introductory article we give a brief overview of the description of the constructions in sign language known as classifiers. We focus on the need to carry out theoretically driven linguistic analyses of their use in order to understand the structure and function of these pervasive devices within the grammars of different sign languages. Research on classifiers at the level of phonology, morphology, syntax, semantics and discourse structure as well as in different populations of signers (native, non-native, child and atypical signers) will assist us in the understanding of these complex structures within the context of current research on sign language linguistics.

After the success of human genome project, proteome is a new emerging field of biochemistry as it provides the knowledge of enzymes (proteins) interactions with different body organs and medicines administrated into human body. Therefore, the study of proteomics is very important for the development of new and effective drugs to control many lethal diseases. In proteomics study, analyses of proteome is essential and significant from the pathological point of views, i.e., in several serious diseases such as cancer, Alzheimer's disease and aging, heart diseases and also for plant biology. The separation and identification of proteomics is a challenging job due to their

This paper presents an efficient numerical method that approximates the complex eigenvalues and eigenvectors in structural systems with viscoelastic damping materials, characterised by the complex structural damping matrix. This new method begins from the solution of the undamped system and approximates the complex eigenpair by finite increments using the eigenvector derivatives and the Rayleigh quotient. It is implemented in three different approaches: single-step, incremental and iterative schemes. The single-step technique is presented for systems with low and medium damping. From numerical examples, it can be verified that the errors committed by the approximate single-step technique with respect to the exact solutions, obtained by the IRAM method, are less than 0.2% when the loss factor of the material damping is lower than 1; this is a considerable improvement on other approximate methods. For higher damped systems an improvement to the previous approach is proposed by an incremental technique that keeps the accuracy without significantly increasing the computational time. The complex eigenproblem for materials whose mechanical properties are dependent on frequency is solved by a fast iterative approach, whose validity is proved using a four-parameter fractional derivative model.

A major tool in the initial recognition and study of terrestrial impact craters, -20% of which are buried beneath postimpact sediments, is geophysics. The general geophysical character of terrestrial impact craters is compiled and outlined with emphasis on its relation to the impact process and as an aid to the recognition of additional impact craters. The most common and conspicuous geophysical signature is a circular gravity low. For simple bowl-shaped craters, gravity models indicate that the anomaly is largely due to the presence of an interior allochthonous breccia lens. In complex craters, modeling indicates that the main contribution to the gravity anomaly is from fractured parautochthonous target rocks in the floor of the crater. The gravity signature of both simple and complex crater forms can be modeled well, using known morphometric parameters of impact structures. The size of the gravity anomaly generally increases with increasing crater diameter reaching a maximum of--20-30 mGal at diameters D of -20-30 km. Further increases in D have a negligible effect on the magnitude of the gravity anomaly due to lithostatic effects on deep fractures. The general gravity signature of a simple low can be modified by target rock and erosional effects, and there is a tendency for larger complex structures (D > 30 km) to exhibit a relative gravity high restricted to the crater center and extending out to <0.5D. The magnetic signature of craters is more varied. The dominant effect is a magnetic low due to a reduction in susceptibility. Large structures (D > 40 km) tend to exhibit central high-amplitude anomalies, with dimensions of <0.5D, due to remanently magnetized bodies in the target rocks. The sources of these bodies are wide ranging and include the effects of shock, heat, and chemical alteration. The few studies over craters involving electrical methods indicate resistivity lows coinciding with the extent of the potential field anomalies and related to fracturing. Seismic techniques, particularly reflection surveys, have provided details of the subsurface structure of craters. Incoherent reflections and reduced seismic velocities due to brecciation and fracturing are expected, the degree of coherency of reflections increasing away from and below the center of the structure. From the various geophysical techniques a set of general criteria can be established that correspond to the geophysical signature of impact craters. These criteria can be used to evaluate the hypothesis that any particular set of geophysical anomalies is due to impact. Confirmation of an impact origin, however, is based on geologic evidence. 20% of the known terrestrial craters are buffed beneath postimpact sediments. Thus the recognition, which is based on surface morphological and morphometric observations of terrestrial impact craters, differs from planetary impact craters. Terrestrial impact craters are recognized largely by lithological and structural evidence, with a major tool in the recognition of a lithostmctural anomaly being geophysics. Many terrestrial impact structures were identified initially as geophysical anomalies and their impact origin established later through geologic studies, for example, Eagle Butte, Canada. Terrestrial data are currently the main source of information on the nature of the third dimension of impact craters ranging up to over 100 km in diameter. This pages 161-181 Paper number 92RG00192 162 ß Pilkington and Grieve: SIGNATURE OF TERRESTRIAL IMPACT CRATERS 29, 1 /REVIEWS OF GEOPHYSICS

One of the causes of aviation accidents is lack of overview and analysis of the data particularly obtained from its maintenance operation performance. The aircraft maintenance system of an airline is a complex structure with information flow involving various stakeholders ensuring aircraft airworthiness while adhering to several regulatory standards, policies and procedures of Federal Aviation Administration (FAA). Further, the prevalence of HCI design methodologies to perform data management in the aviation industry is very negligible. Little literature exists on information management of the data obtained from various aircraft maintenance processes which have a direct effect on the safety of the aircraft and hence the airline. The current research studies the intricacies of the aircraft maintenance system work flow processes, in order to develop a system that analyzes the aviation maintenance errors. This paper discusses the advantages of using a knowledge management system that shares information and knowledge across various operational hierarchies.

Two geophysical techniques were integrated to map the groundwater aquifers on complex geological settings, in the crystalline basement terrain in northeast Nuba Mountains. The water flow is structurally controlled by the northwest-southeast extensional faults as one of several in-situ deformational patterns that are attributed to the collision of the Pan-African oceanic assemblage of the Nubian shield against the pre-Pan African continental crust to the west. The structural lineaments and drainage systems have been enhanced by the remote sensing technique. The geophysical techniques used are: vertical electrical soundings (VES) and electrical resistivity tomography (ERT), in addition to hydraulic conductivity measurements. These measurements were designed to overlap in order to improve the producibility of the geophysical data and to provide a better interpretation of the hydrogeological setting of the aquifer complex structure. Smooth and Block inversion schemes were attempted for the observed ERT data to study their reliability in mapping the different geometries in the complex subsurface. The VES data was conducted where ERT survey was not accessible, and inverted smoothly and merged with the ERT in the 3D resistivity grid. The hydraulic conductivity was measured for 42 water samples collected from the distributed dug wells in the study area; where extremely high saline zones were recorded and have been compared to the resistivity values in the 3D model.

The teeth of every primate, living and extinct, are covered by a hard, durable layer of enamel. This is not unique: Almost all mammals have enamel-covered teeth. In addition, all of the variations in enamel structure that occur in primates are also found in other groups of mammals. Nevertheless, the very complexity of enamel and the variation we see in it on the teeth of living and fossil primates raise questions about its evolutionary significance. Is the complex structure of primate enamel adaptive? What, if anything, does enamel structure tell us about primate phylogeny? To answer these questions, we need to look more closely at the characteristics of prismatic enamel in primates and at the distribution of those characteristics, both in relation to our knowledge of primate dental function and feeding ecology and from a phylogenetic perspective.

In this study, an analysis on the breaking elongation mechanism of the polyester/viscose blended open-end rotor spun yarns has been carried out. In addition, a back propagation multi layer perceptron (MLP) network and a mixture process crossed regression model with two mixture components (polyester and viscose blend ratios) and two process variables (yarn count and rotor speed) are developed to predict the breaking elongation of polyester/viscose blended open-end rotor spun yarns. Seven different blend ratios of polyester/viscose slivers are produced and these slivers are manufactured with four different rotor speed and four different yarn counts in rotor spinning machine. In conclusion, ANN and statistical model both have given satisfactory predictions; however, the predictions of ANN gave relatively more reliable results than those of statistical models. Since the prediction capacity of statistical models is also obtained as satisfactory, it can also be used for breaking elongation (%) prediction of yarns because of its simplicity and non-complex structure. In addition, it is also found in this study that yarn count, rotor speed and breaking elongation of polyester-viscose fibers and the blend ratios of these fibers in the yarn have major effects on yarn breaking elongation.

The aim of this paper is to provide a broad overview of Object Database Management Systems (ODBMSs). It discusses the shortcomings of existing database technology to meet the requirements for &quot;next-generation&quot; applications that require support for richer data types and complex structures. Object and data management requirements for ODBMSs are also briefly reviewed. Six major classification models are presented including Data Models, Architectures, Storage Server Models, Alternative Object Database Strategies, Language Data Models, and Evolution versus Revolution. Areas for standards are briefly considered and, finally, the main strengths and weaknesses are discussed. 1. Introduction The object paradigm has been applied to programming languages, user interfaces, design methodologies, operating systems, hardware architecture, and database systems. This has been prompted by the desire to control complexity and harness the expanding system environment (e.g. multimedia informat...

Various DFT and ab initio methods, including B3LYP, HF, SORCI, and LF-density functional theory (DFT), are used to compute the structures, relative stabilities, spin density distributions, and spectroscopic properties (electronic and EPR) of the two possible isomers of the copper(II) complexes with derivatives of a rigid tetradentate bispidine ligand with two pyridine and two tertiary amine donors, and a chloride ion. The description of the bonding (covalency of the copper-ligand interactions) and the distribution of the unpaired electron strongly depend on the DFT functional used, specifically on the nonlocal DF correlation and the HF exchange. Various methods may be used to optimize the DFT method. Unfortunately, it appears that there is no general method for the accurate computation of copper(II) complexes, and the choice of method depends on the type of ligands and the structural type of the chromophore. Also, it appears that the choice of method strongly depends on the problem to be solved. LF-DFT and spectroscopically oriented CI methods (SORCI), provided a large enough reference space is chosen, yield accurate spectroscopic parameters; EDA may lead to a good understanding of relative stabilities; accurate spin density distributions are obtained by modification of the nuclear charge on copper; solvation models are needed for the accurate prediction of isomer distributions.

We can notice that the general public awareness on ethical aspects of technology is increasing. The high level of media attention given to computerrelated disasters in technical systems such as the explosion of Ariane V in 1996 and the Therac-25 computerized radiation machine overdoses has increased interest in Computer Ethics.

As a business family moves from the second to the third, fourth, and succeeding generations, and seeks to maintain shared family control of its often highly diversified financial and business assets, families around the world have created a complex web of structures, agreements, councils, and forms of accountability to manage their wealth. In working with such multigenerational dynasties around the world, we have begun to see that successful transmission of wealth, and sustaining of family connection, depends on a highly creative web of such structures. This article will focus on the structures and agreements that we have seen in such families. A family that owns a business, or substantial investments, is at the intersection of several complex systems and serves a multitude of masters, purposes, and constituencies. Facing continual change from the business environment, and from internal pressures as people develop, in order to thrive, the family must develop a clear infrastructure to manage the interrelationships of people, business, and investment. It must regulate and integrate the interests and concerns of the many people in many ways. As a family enters the third generation, it has become a complex structure with several family branches, diverse interests and stakeholders, and challenges to sustain collaboration and effectiveness. This article presents the key challenges that a family must face to create an effective dynasty over generations and illustrates models and best practices for how effective family dynasties develop a governance infrastructure as they grow into multigenerational family dynasties. It highlights the core structures that make up effective governance and the key agreements that allow a dynasty to work.

Leontopodic acid-a novel full substituted hexaric acid derivative, was isolated from the aerial parts of Edelweiss (Leontopodium alpinum Cass.) as one of the major compounds. The complex structure of leontopodic acid-2-[(3S)-3-hydroxybutanoate]-3,4,5-tris-[(2E)-3-(3,4-dihydroxyphenyl)-2-propenoate]-D-glucaric acid-was elucidated by mass spectrometry, 1D-and 2D NMR spectroscopy and HPLC monitored transesterification. Leontopodic acid exhibited pronounced antioxidative effects in the Briggs-Rauscher (BR) model [(r.a.c.) m 3.4G0.5] and the trolox equivalent antioxidant capacity (TEAC) method (TEAC value of 1.53G0.11). The antioxidative properties of this compound were confirmed by the 3D method, an in vitro assay evaluating DNA protection against oxidative damage (IC 50 : 1.89 mM). q Tetrahedron 61 (2005) 4621-4630 Figure 1. Structure of leontopodic acid.