bluuebunny/crossref_metadata_2025_split huggingface dataset:
Object‐oriented hierarchical mesh refinement with CHARMS
Authors: Krysl Petr , Trivedi Abhishek , Zhu Baozhi 
Published: June 2004

AbstractA new approach to the construction of adaptive approximations on finite element meshes and also in more general settings, including approximations on subdivision surfaces, had been recently proposed by Krysl, Grinspun, and Schröder. This paper outlines how the general refinement algorithms may be specialized to some common finite element discretizations in two and three dimensions, discusses the design of nested meshes, and delves into the algorithmic, design, and implementation issues in an object oriented software framework (http://hogwarts.ucsd.edu/∼pkrysl/CHARMS). Copyright © 2004 John Wiley & Sons, Ltd.
Evaluating the LCD algorithm for solving linear systems of equations arising from implicit SUPG formulation of compressible flows
Authors: Catabriga Lucia , Coutinho Alvaro L. G. A. , Franca Leopoldo P. 
Published: June 2004

AbstractIn this work we evaluate the performance of the left conjugate direction method recently introduced by Yuan, Golub, Plemmons and Cecílio for the solution of non‐symmetric systems of linear equations arising from the implicit semi‐discrete SUPG finite element formulation of advective–diffusive and inviscid compressible flows. We extend the original algorithm to accommodate restarts and typical element‐by‐element preconditioners. We also show how to select the first left conjugate vector to start LCD. Several problems are solved, accessing performance parameters such as number of iterations, memory requirements and CPU times, and results are compared with other algorithms, such as GMRES, TFQMR and Bi‐CGSTAB. Copyright © 2004 John Wiley & Sons, Ltd.
Stochastic inverse heat conduction using a spectral approach
Authors: Narayanan Velamur Asokan Badri , Zabaras Nicholas 
Published: June 2004

AbstractAn adjoint‐based functional optimization technique in conjunction with the spectral stochastic finite element method is proposed for the solution of an inverse heat conduction problem in the presence of uncertainties in material data, process conditions and measurement noise. The ill‐posed stochastic inverse problem is restated as a conditionally well‐posed L2 optimization problem. The gradient of the objective function is obtained in a distributional sense by defining an appropriate stochastic adjoint field. The L2 optimization problem is solved using a conjugate‐gradient approach. Accuracy and effectiveness of the proposed approach is appraised with the solution of several stochastic inverse heat conduction problems. Copyright © 2004 John Wiley & Sons, Ltd.
Solution of a multidimensional inverse radiation problem by means of mode reduction
Authors: Park H. M. , Sung M. C. 
Published: June 2004

AbstractThe Karhunen–Loève Galerkin procedure is employed to solve an inverse radiation problem of determining the time‐varying strength of a heat source, which mimics flames in a furnace, from temperature measurements in three‐dimensional participating media where radiation and conduction occur simultaneously. The inverse radiation problem is solved through the minimization of a performance function, which is expressed by the sum of square residuals between calculated and observed temperature, using a conjugate gradient method. Through the Karhunen–Loève Galerkin procedure, one can represent the system dynamics with a minimum degree of freedom, and consequently the amount of computation required in the solution of the inverse problem is reduced drastically when the present technique is adopted. Copyright © 2004 John Wiley & Sons, Ltd.
Block preconditioners for symmetric indefinite linear systems
Authors: Toh Kim‐Chuan , Phoon Kok‐Kwang , Chan Swee‐Huat 
Published: June 2004

AbstractThis paper presents a systematic theoretical and numerical evaluation of three common block preconditioners in a Krylov subspace method for solving symmetric indefinite linear systems. The focus is on large‐scale real world problems where block approximations are a practical necessity. The main illustration is the performance of the block diagonal, constrained, and lower triangular preconditioners over a range of block approximations for the symmetric indefinite system arising from large‐scale finite element discretization of Biot's consolidation equations. This system of equations is of fundamental importance to geomechanics. Numerical studies show that simple diagonal approximations to the (1,1) block K and inexpensive approximations to the Schur complement matrix S may not always produce the most spectacular time savings when K is explicitly available, but is able to deliver reasonably good results on a consistent basis. In addition, the block diagonal preconditioner with a negative (2,2) block appears to be reasonably competitive when compared to the more complicated ones. These observation are expected to remain valid for coefficient matrices whereby the (1,1) block is sparse, diagonally significant (a notion weaker than diagonal dominance), moderately well‐conditioned, and has a much larger block size than the (2,2) block. Copyright © 2004 John Wiley & Sons, Ltd.
Study on semi‐conjugate direction methods for non‐symmetric systems
Authors: Dai Yu‐Hong , Yuan Jinyun 
Published: June 2004

AbstractSome theoretical problems and implementation problems are studied here for the semi‐conjugate direction method established by Yuan, Golub, Plemmons and Cecilio (2002). The existence of semi‐conjugate directions is proved for almost all matrices except skew‐symmetric matrices. A new technique is proposed to overcome the breakdown problem appeared in the semi‐conjugate direction method. In the implementation of the semi‐conjugate direction method, the generation of the semi‐conjugate direction is very important and necessary, but very expensive. The technique of limited‐memory is introduced to economize the cost of the generation of the semi‐conjugate direction in the Yuan–Golub– Plemmons–Cecilio algorithm. Finally, some numerical experiments are given to confirm our theoretical results. Our results illustrate that the semi‐conjugate direction method is very nice alternative for solving non‐symmetric systems, and the limited‐memory left conjugate direction method is a good improvement of the left conjugate direction method. Copyright © 2004 John Wiley & Sons, Ltd.
A matter of high resolution? The Eemian Interglacial (OIS 5e) in north‐central Europe and Middle Palaeolithic subsistence
Authors: Gaudzinski S. 
Published: June 2004

AbstractThe Eemian Interglacial in north‐central Europe describes a phase of ca. 10,000–11,000 years for which detailed palaeoenvironmental reconstruction is available. Hominid subsistence during this period is considered based on evidence from the German sites of Lehringen, Gröbern, Neumark‐Nord and Taubach. It is concluded that the overall subsistence strategies of the Neanderthals were directed towards highly efficient resource exploitation irrespective of the environmental context. Problems immanent to interpretations of Middle Palaeolithic hominid responses to the palaeoenvironment are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Subsistence behaviours in a Middle Palaeolithic site in Poland: the Raj Cave
Authors: Patou‐Mathis M. 
Published: June 2004

AbstractThis paper presents an overview of mammal remains from one of the most important Middle Palaeolithic archaeological sites in Poland: Raj cave. This site lies near Kielce. Archaeological materials in cultural layers 4 and 6 are described as belonging to the Charentian culture. The stratigraphic sequence in its entirety may have been deposited during the Wechsel Interpleniglacial, equivalent to isotopic stage 3. Layer 4 would correspond at best to an interstadial phase, and layer 6 to a stadial. The environment of layer 4 was mixed, consisting of prairie and woodland, and the climate was relatively temperate and humid. In layer 6, the forests retreated while the steppe increased, and the climate became cold and relatively dry. In the lower layer (4) cave bear (Ursus spelaeus) dominates carnivore remains. In the upper cultural layer (6), cave bear and cave hyena (Crocuta spelaea) are the best represented carnivore taxa. In layer 4, hunting appears diversified. On the other hand, in layer 6 hunting seems to be oriented towards acquisition of the horse, but reindeer and large bovids are also abundant. A large quantity of reindeer shed antlers were discovered in this layer; the role of humans as collectors has yet to be proven. Clear evidence of human modification of the bone surfaces is very rare; few cut marks are observed. Raj cave can be considered a seasonal camp, occupied from the end of spring to the beginning of autumn in the case of layer 6. Copyright © 2004 John Wiley & Sons, Ltd.
The Middle Palaeolithic and late Pleistocene Tasmania hunting behaviour: a reconsideration of the attributes of modern human behaviour
Authors: Cosgrove Richard , Pike‐Tay Anne 
Published: June 2004

AbstractThe murky biological status of Neanderthals has inspired many behavioural paradigms. We ask if it is possible to differentiate behavioural changes in an evolutionary sense (archaic to modern) from innovative/evolutionary changes in behaviour due to localised adaptations to changing environments. Our approach to Neanderthal ecology here is comparative. Both lithic and faunal analyses of Pleistocene Tasmanian sites dating back to 35,000 BP show patterns similar to Middle Palaeolithic Eurasia. Yet the anatomically modern humans who first populated Australia exhibited modern cultural behaviour by crossing from Southeast Asia to Greater Australia by boat and colonising every environmental zone on the continent by at least 35,000 BP. If the Tasmanian archaeological sequence parallels that of the Mousterian, then the earliest Aboriginal colonisers of Greater Australia were either archaic in a behavioural sense (a notion that does not fit with the available evidence), or the interpretation of what indicates archaic behaviour must be reassessed.Results from dental growth‐increment analyses of large game from Franco‐Cantabrian Palaeolithic sites show shifts in human mobility and subsistence strategies. Compilation of control samples of teeth of recent animals (e.g. Cervus, Rangifer, Equus, Capreolus, Bos) of known age and date‐of‐death has been requisite to these growth‐increment studies. Here we apply skeletochronological analysis to Bennett's wallaby (Macropus rufogriseus) from Tasmania's earliest sites, presenting results of aging techniques of molar eruption and seasonal annuli growth. These suggest that hunting pressure was relatively low on wallaby populations and that hunters occupied these upland valleys principally between autumn and early spring. We expect these data to support more robust hypotheses of both mortality and seasonal hunting patterns of this principal macropod prey species, as well as consideration of the question of ‘archaic’ versus ‘modern’ ecological adaptations. Copyright © 2004 John Wiley & Sons, Ltd.
Eat what is there: hunting and gathering in the world of Neanderthals and their neighbours
Authors: Bar‐Yosef O. 
Published: June 2004

AbstractThe current state of our knowledge of Neanderthal hunting and gathering is reviewed, with particular emphasis on the ‘transition’ from the Middle to the Upper Palaeolithic. It is argued that the zooarchaeological data do not support any general change in strategy during this transition, and that Middle and Upper Palaeolithic hunting and gathering was largely determined by what was available seasonally in the local environment. Copyright © 2004 John Wiley & Sons, Ltd.
Women, the labor market, and the declining relative quality of teachers
Authors: Corcoran Sean P. , Evans William N. , Schwab Robert M. 
Published: June 2004

AbstractSchool officials and policymakers have grown increasingly concerned about their ability to attract and retain talented teachers. A number of authors have shown that in recent years the brightest students—at least those with the highest verbal and math scores on standardized tests—are less likely to enter teaching. In addition, it is frequently claimed that the ability of schools to attract these top students has been steadily declining for years. There is, however, surprisingly little evidence measuring the extent to which this popular proposition is true. We have good reason to suspect that the quality of those entering teaching has fallen over time. Teaching has for years remained a predominately female profession; at the same time, the employment opportunities for talented women outside teaching have soared. In this paper, we combine data from five longitudinal surveys of high school graduates spanning the classes of 1957 to 1992 to examine how the propensity for talented women to enter teaching has changed over time. While the quality of the average new female teacher has fallen only slightly over this period, the likelihood that a female from the top of her high school class will eventually enter teaching has fallen dramatically. © 2004 by the Association for Public Policy Analysis and Management.
Alternative measures of economic success among TANF participants: Avoiding poverty, hardship, and dependence on public assistance
Authors: Cancian Maria , Meyer Daniel R. 
Published: June 2004

AbstractCurrent debates about the success of TANF reforms have been obscured by the use of inconsistent indicators of success, as well as by measurement difficulties associated with alternative indicators. This paper considers conceptual and measurement issues associated with three different indicators of economic well‐being: independence from public assistance, having income above the poverty threshold, and freedom from material hardship. Survey and administrative data from a sample of TANF participants illustrate the sensitivity of conclusions to alternative ways of measuring each indicator. Also considered is the extent to which dependence, poverty, and hardship coincide, or capture important differences in outcomes. The principles underlying TANF reforms have implications for appropriate measures of economic well‐being, as the empirical importance of these implications demonstrates. © 2004 by the Association for Public Policy Analysis and Management.
Synthesis of block copolymers from PDMS macroinitiators
Authors: Peng Hui , Cheng Shiyuan , Feng Linxian , Fan Zhiqiang 
Published: June 2004

AbstractThe synthesis of polystyrene‐b‐polydimethylsiloxane‐b‐polystyrene (PSt‐b‐PDMS‐b‐PSt) copolymers is described. Commercially available difunctional PDMS containing vinylsilyl terminal species was reacted with hydrogen bromide resulting in the PDMS macroinitiators. The terminal alkyl bromide groups were then used as initiators for atom transfer radical polymerization (ATRP) to produce block copolymers. Using this technique, triblock copolymers consisting of a PDMS centre block and polystyrene terminal blocks were synthesized. ATRP of St from those macroinitiators showed linear increases in Mn with conversion, demonstrating the effectiveness of ATRP to synthesize a variety of inorganic/organic polymer hybrids. Copyright © 2004 Society of Chemical Industry
Quantitative proteome profiling during the fermentation process of pleiotropic Bacillus subtilis mutants
Authors: Antelmann Haike , Sapolsky Ron , Miller Brian , Ferrari Eugenio , Chotani Gopal , Weyler Walter , Gaertner Alfred , Hecker Michael 
Published: June 2004

AbstractUsing a combined quantitative proteomic and bioinformatic approach, we monitored the cytoplasmic proteome profile of the Gram‐positive bacterium Bacillus subtilis during a fermentation process in complex medium. Proteome signatures were applied to elucidate the physiological changes occurring in the gene expression profile during growth. Furthermore, we determined the significance level of quantitative proteome changes, identified relative to the threshold of scatter in replicated samples and developed a statistically rigorous method that allowed us to determine significant fold‐changes at 95% confidence between different proteomes. Different functional groups of proteins were clustered according to their pattern of significant expression changes. The largest group is induced by the exhaustion of glucose and the presence of alternative carbon and nitrogen sources. Furthermore, depletion of glucose caused the induction of the trichloroacetic acid (TCA) cycle enzymes and the downregulation of glycolytic enzymes. The onset of the transition phase may be provoked by amino acid starvation, resulting in the RelA‐dependent repression of proteins involved in the translation process and in the induction of amino acid biosynthetic pathways. Comparisons between the parental strain and two subtilisin‐hypersecreting strains revealed only small cytoplasmic differences in the main metabolic pathways. Instead, the overproduction of degradative enzymes in both of these mutants was reflected in the extracellular proteome.
Proteomic tools to characterize the protein fraction of Equidae milk
Authors: Miranda Guy , Mahé Marie‐Françoise , Leroux Christine , Martin Patrice 
Published: June 2004

AbstractThe principal components of the protein fraction in pony mare's milk have been successfully identified and partially characterized using proteomic tools. Skimmed pony mare's milk was fractionated by either reversed phase‐high‐performance liquid chromatography (RP‐HPLC) on a C4 column or a bi‐dimensional separation technique coupling RP‐HPLC in the first dimension and sodium dodecyl sulfate‐polyacrylamide electrophoresis (SDS‐PAGE) in the second dimension (two‐dimensional RP‐HPLC/SDS‐PAGE). The fractions thus obtained were analyzed by Edman N‐terminal microsequencing and mass determination, with or without tryptic digestion, on a matrix‐assisted laser desorption/ionization‐time of flight spectrometer. Based on the sequence and molecular mass information obtained, identifications were achieved through a protein database search using homology or pattern research algorithms. This methodological approach was shown to be rapid, efficient and reliable in identifying the principal proteins in pony mare's milk. κ‐, αs1‐, αs2‐, and β‐casein, lysozyme C, α‐lactalbumin and β‐lactoglobulin I and II were thus identified. αs1 and β‐caseins displayed polymorphic patterns, probably due to alternative splicing processes leading to casual exon skipping events involving exons 7 and 14 in αs1‐casein and exon 5 in β‐casein. Edman N‐terminal microsequencing over 35 amino acid residues, for pony αs1‐casein, clearly demonstrated the occurrence, in Equidae, of a splicing pattern similar to that reported in rodents, characterized by the constitutive outsplicing of exon 5. Pony mare's milk SDS‐PAGE and RP‐HPLC patterns were compared with those obtained for other milks (cow, goat and human), as were the relative levels of caseins and major whey proteins in these milks. Our results provide further evidence to support the notion that Equidae milk is closer to human breast milk than milk from bovine and caprine with respect to the casein and lysozyme C contents and casein/whey proteins ratio.
Antioxidant role of human haptoglobin
Authors: Tseng Chi Feng , Lin Chia Ching , Huang Hsing Yi , Liu Huei Chun , Mao Simon J. T. 
Published: June 2004

AbstractHuman plasma haptoglobin (Hp) is classified according to three phenotypes: Hp 1‐1, 2‐1, and 2‐2 attributed by their two common alleles 1 and 2. Clinically, the 2–2 phenotype is associated with the risk of cardiovascular diseases and diabetes mellitus in patients. In this study, we demonstrate that Hp is an extremely potent antioxidant, which directly protects low density lipoprotein from Cu2+‐induced oxidation. Its potency was markedly superior to probucol (one of the most potent antioxidants). Ranking of the IC50 of antioxidant activity was as follows: Hp 1‐1 ≳ Hp 2‐1 ≳ Hp 2‐2 ≳ probucol ≳ vitamin E. Blockage of disulfide linkages between Hp subunits, not only abolished the α‐helical content but also diminished the ability of Hp to form a complex with hemoglobin. The modified Hp subunits exerted almost 4 times greater antioxidant activity than that of native Hp. To investigate the antioxidant role of Hp on the cellular level, the cDNA of Hp 1‐1 was cloned, introduced into the pcDNA3.0 vector which contains the cytomega lovirus promoter and transfected into chinese hamster ovary (CHO)‐K1 cells. Following transfection, CHO cells were able to express Hp 1–1 protein and significantly (p < 0.001) elevated cell tolerance against oxidative stress. Transfected cells showed 2‐fold higher resistance to hydrogen peroxide exposure for 24 h compared to control cells. Thus, Hp plays a provocative antioxidant role as demonstrated by our in vitro and ex vivo studies.
The kinetics of the epoxy amine cure reaction from a solvation perspective
Authors: Talbot James D. R. 
Published: June 2004

AbstractThis article investigates the role of solvation effects in the autocatalysis reaction of the epoxy–amine cure reaction. A single‐phase three component model was developed encompassing a two‐component reaction mix and a single polymeric product. The reaction was modelled as an SN2 reaction. Association of the nucleophile with each component in the reaction was defined via a binding constant. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3579–3586, 2004
Spectroscopic studies of the conformational properties of naphthoyl chitosan in dilute solutions
Authors: Wu Yusong , Seo Toshihiro , Maeda Shiro , Dong Yanming , Sasaki Takashi , Irie Satoshi , Sakurai Kensuke 
Published: June 2004

AbstractA naphthoyl chitosan derivative was prepared, and its conformations in dilute solutions were characterized with spectroscopic methods, including circular dichroism (CD) spectroscopy and fluorescence emission spectroscopy. The CD spectrum of this polymer showed a negative band at about 295 nm in dimethyl sulfoxide (DMSO), indicating that the polymer adopted a helical secondary structure. A helix reversion occurred at concentrations greater than 1 mg/mL. The intensity of the CD signal decreased with the addition of water to the solution, and this suggested a change from a helical conformation to a looser one as a result of the collapse of intramolecular hydrogen bonds. In the fluorescence emission experiments, two kinds of excimer emission bands were detected at 375 and 425 nm, and they were assigned to a partially overlapped dimer with a twisted geometry and a fully overlapped dimer with a sandwichlike geometry, respectively. Adding water to a solution of naphthoyl chitosan in DMSO resulted in a gradual reduction of the emission intensity at 375 nm, and this implied that the twisted arrangement of the chromophore was destroyed by the presence of water. The relative intensity (i.e., the ratio of the intensity of the excimer emission at 425 nm to that of the excimer emission at 375 nm) depended on the solvent (DMSO, N,N‐dimethylformamide, N,N‐dimethylacetamide, and 1‐methyl‐2‐pyrrolidinone), and this indicated that the conformation of naphthoyl chitosan was solvent‐dependent. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2747–2758, 2004
New version of the Rayleigh–Schrödinger perturbation theory: Examples
Authors: Kalhous Miloš , Skála L. , Zamastil J. , Čížek J. 
Published: June 2004

AbstractIt has been shown in our preceding papers that the linear dependence of the perturbation wave functions on the perturbation energies makes possible to calculate the exact perturbation energies from the values of the perturbation wave functions corresponding to arbitrarily chosen trial perturbation energies. The resulting version of the perturbation theory is very simple and can be used at large orders. In this paper, this method is applied to a few problems and its numerical properties are discussed. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004