bluuebunny/crossref_metadata_2025_split huggingface dataset:
The convergence of Jacobi–Davidson iterations for Hermitian eigenproblems
Authors: van den Eshof Jasper 
Published: January 2005

AbstractRayleigh quotient iteration is an iterative method with some attractive convergence properties for finding (interior) eigenvalues of large sparse Hermitian matrices. However, the method requires the accurate (and, hence, often expensive) solution of a linear system in every iteration step. Unfortunately, replacing the exact solution with a cheaper approximation may destroy the convergence. The (Jacobi‐) Davidson correction equation can be seen as a solution for this problem. In this paper we deduce quantitative results to support this viewpoint and we relate it to other methods. This should make some of the experimental observations in practice more quantitative in the Hermitian case. Asymptotic convergence bounds are given for fixed preconditioners and for the special case if the correction equation is solved with some fixed relative residual precision. A dynamic tolerance is proposed and some numerical illustration is presented. Copyright © 2002 John Wiley & Sons, Ltd.
H‐self‐adjoint matrices. Application to radiosity
Authors: Leblond Michel 
Published: January 2005

AbstractIn computer graphics, in the radiosity context, a linear system Φx=b must be solved and there exists a diagonal positive matrix H such that H Φ is symmetric. In this article, we extend this property to complex matrices: we are interested in matrices which lead to Hermitian matrices under premultiplication by a Hermitian positive‐definite matrix H. We shall prove that these matrices are self‐adjoint with respect to a particular innerproduct defined on ℂn. As a result, like Hermitian matrices, they have real eigenvalues and they are diagonalizable. We shall also show how to extend the Courant–Fisher theorem to this class of matrices. Finally, we shall give a new preconditioning matrix which really improves the convergence speed of the conjugate gradient method used for solving the radiosity problem. Copyright © 2002 John Wiley & Sons, Ltd.
A combination of potential reduction steps and steepest descent steps for solving convex programming problems
Authors: Shi Yixun 
Published: January 2005

AbstractThis paper studies the possibility of combining interior point strategy with a steepest descent method when solving convex programming problems, in such a way that the convergence property of the interior point method remains valid but many iterations do not request the solution of a system of equations. Motivated by this general idea, we propose a hybrid algorithm which combines a primal–dual potential reduction algorithm with the use of the steepest descent direction of the potential function. The $O(\sqrt{n}\left|{\ln {\epsilon}} \right|)$ complexity of the potential reduction algorithm remains valid but the overall computational cost can be reduced. Our numerical experiments are also reported. Copyright © 2002 John Wiley & Sons, Ltd.
Recording dental caries in archaeological human remains
Authors: Hillson Simon 
Published: January 2005

AbstractDental caries is an important condition to record in archaeological collections, but the way in which recording is carried out has a large effect on the way in which the results can be interpreted. In living populations, dental caries is a disease that shows a strong relationship with age. Both the nature of carious lesions and their frequency change with successive age groups from childhood to elderly adulthood. There is also a progression in the particular teeth in the dentition which are most commonly affected and, in general, the molars and premolars are involved much more frequently than the canines and incisors. Lower teeth are usually affected more than upper, although the condition usually involves the right and left sides fairly equally. In the high tooth wear rate populations represented by many archaeological and museum collections, there is a complex relationship between the form of lesions and the state of wear, which adds yet another range of factors to the changing pattern of caries with increasing age. In the same populations, chipping, fracture and anomalous abrasion of teeth are also common, and these contribute similarly to the distribution and forms of carious lesion observed. Amongst the living, the pattern of ante‐mortem tooth loss is important in understanding caries and, in archaeological material, there is also the complicating factor of post‐mortem tooth loss. Finally, there is the question of diagnosis. There are diagnostic problems even in epidemiological studies of living patients and, for archaeological specimens, diagenetic change and the variable preservation of different parts of the dentition add further complications. For all these reasons, it is difficult to define any one general index of dental caries to represent the complete dentition of each individual, which would be universally suitable for studying a full range of collections from archaeological sites or museums. Variation in the nature of collections, their preservation, tooth wear, and ante‐mortem and post‐mortem tooth loss mean that when such a general index appears to differ between sites, there could be many other reasons for this, in addition to any genuine differences in caries incidence and pattern that might have been present. It is suggested here that the best approach is instead to make comparisons separately for each tooth type, age group, sex, lesion type and potential lesion site on the tooth. Copyright © 2001 John Wiley & Sons, Ltd.
Periapical lesions and dental wear in the early Maori
Authors: Kieser J.A. , Kelsen A. , Love R. , Herbison P.G.P. , Dennison K.J. 
Published: January 2005

AbstractDental wear and intrabony lesions were evaluated in a sample of 225 skulls (136 male) of pre‐contact New Zealand Maoris. The degree and direction of surface wear was scored according to the method of Molnar (Molnar 1971. Human tooth wear, tooth function and cultural variability. American Journal of Physical Anthropology34: 175–190) and revealed severe surface loss in both males and females with horizontal wear being the dominant pattern (62.4% male, 57.5% female). The width of coronal tissue above the pulp chamber, as well as the maximum depth and width of periapical lesions, was measured from both standard radiographs and digital images. The high prevalence of periapical pathology in the Maori underlined the extreme nature of dental wear in these people. It is postulated that this degree of tooth loss may be attributable to a change in diet from large birds to marine‐dependence, the introduction of the kumara to New Zealand, dental erosion and finally, to the excessive masticatory forces exerted by a robust facial complex on normally sized teeth. Fenestrated lesions were highly prevalent (83% of skulls) and were centered mostly on the maxilla, with an even distribution among tooth classes. The finding of periapical lesions in teeth with minimal observable wear was attributed to traumatic occlusion. Copyright © 2001 John Wiley & Sons, Ltd.
Neolithic seal exploitation on the Åland Islands in the Baltic Sea on the basis of epiphyseal fusion data and metric studies
Authors: Storå Jan 
Published: January 2005

AbstractThe exploitation of marine resources was of central importance in the subsistence economy on the Åland Islands during the Stone Age. In this study four faunal assemblages from archaeological sites which date to approximately 3300–1800 cal BC are discussed. On all sites seals clearly dominate the mammal fauna with the harp seal (Phoca groenlandica) as the most common species followed by the ringed seal (Phoca hispida). Epiphyseal fusion data and metric comparisons are used to reconstruct the strategies humans used to exploit seals. The results show that the main prey were yearlings and adults and that seasonal hunting strategies were implemented. Ringed seal was hunted on the breeding grounds in late winter. Harp seal was hunted during a longer period of the year, from late spring until early winter. Differences in the hunting strategies directed toward the two species appear to be related to behavioral patterns of the seals. Copyright © 2002 John Wiley & Sons, Ltd.
Environmental effects of tourism industry investments: an inter‐temporal trade‐off
Authors: Kort Peter M. , Greiner Alfred , Feichtinger Gustav , Haunschmied Josef L. , Novak Andreas , Hartl Richard F. 
Published: January 2005

AbstractEfficient investment programmes in touristic infrastructure have to take into consideration that any kind of tourism reduces the environmental quality. Since pollution shows negative repercussions as concerns the attractiveness of a touristic region, tourism planners have to determine a trade‐off between adequate services for tourists and a clean environment. To deal with this problem in a dynamic context, a three‐state optimal control model is formulated. It turns out that, even if pollution reduction is not a goal in itself, the profit‐maximizing tourism industry should care for ecological conservation. The paper further shows that persistent periodic investment policies are optimal for realistic parameter sets, and provides an economic intuition for such behaviour. From an economic point of view, this result implies that expansionary periods with high investment are followed by periods of stagnation with low investment. Copyright © 2002 John Wiley & Sons, Ltd.
Trajectory optimization involving sloshing media
Authors: Leonpacher Harald , Douglas Steven S. , Woolley Neil H. , Kraft Dieter 
Published: January 2005

AbstractThis paper is concerned with the optimization of the transport motion of an open topped fluid filled container within a warehouse environment. In particular, optimal trajectories of the motion of the driver–container system in two‐dimensional space will be investigated via numerical solutions of the model equations using sequential quadratic programming. The fluid and the mechanical facility that moves the container are subject to several constraints. The objective of the optimization is the time to transport the container from an initial position to its final destination within the warehouse. Optimization criteria are investigated to control the movement of the fluid within the container. The systems of ordinary and partial differential equations, representing the dynamics of the models are solved numerically using a direct shooting method. The resulting non‐linear programming problem is solved using sequential quadratic programming (SQP). Copyright © 2002 John Wiley & Sons, Ltd.
Faith organizations and neighbourhood councils in Los Angeles
Authors: Musso Juliet Ann , Kitsuse Alicia , Cooper Terry L. 
Published: January 2005

AbstractFollowing reforms to the city charter in 1999, the City of Los Angeles is currently implementing a city‐wide system of neighbourhood councils that is intended to increase citizen participation in local governance and make city agencies more responsive to local needs. As neighbourhood council formation has gotten underway, faith organizations (FOs) have been identified as a promising resource for mobilizing involvement among groups that are traditionally underrepresented in the governance process. This article discusses the potential value of FOs' involvement in neighbourhood councils, as well as the likely obstacles to their participation, and reports preliminary findings from ongoing field research on neighbourhood council formation in Los Angeles. Given the diversity of religious missions and attitudes toward political involvement among American faith institutions we find it difficult to generalize about the likely role of the faith community in neighbourhood councils. However, the historical focus of Christian churches on issues of social justice as opposed to local community action, as well as the relative lack of participation by FOs in neighbourhood council formation to date, suggests that widespread involvement of FOs in the neighbourhood council process may be difficult to achieve. A targeted strategy of outreach and organizing directed toward those FOs most likely to participate seems required. Copyright © 2002 John Wiley & Sons, Ltd.
Preparation of polyaniline‐sulfate salt ­by emulsion and aqueous ­polymerization pathway without using ­protonic acid
Authors: Palaniappan S. 
Published: January 2005

AbstractAniline was polymerized directly into polyaniline‐sulfate salt without using protonic acid in this work. Polyaniline‐sulfate salt was prepared by emulsion and aqueous polymerization pathways. The dopant i.e. sulfate ion in polyaniline‐sulfate salt was generated from ammonium persulfate which was used for oxidizing aniline. Ammonium persulfate acts both as oxidizing agent as well as protonating agent in the polymerization process of aniline to polyaniline salt. The efficiency of oxidizing and protonating power of ammonium persulfate is increased by the use of surfactant. The activity of ammonium persulfate is further increased by the use of sulfuric acid as protonic acid. It may be necessary to consider the effect of sulfate ion which is generated during the oxidation process of aniline in the chemical polymerization of aniline to polyaniline salt by ammonium persulfate either aqueous or emulsion polymerization pathway in the presence of protonic acid/functionalized protonic acid. Copyright © 2001 John Wiley & Sons, Ltd.
Catalytic behaviors of silica‐supported methylcellulose‐L‐phenyl alanine–platinum complexes in asymmetric hydrogenation of diacetone alcohol
Authors: Huang Kai , Xue Lei , Huang Mei‐Yu , Jiang Ying‐Yan 
Published: January 2005

AbstractA new chiral natural bio‐polymer–metal complexe, silica‐supported methylcellulose‐L‐phenyl alanine–platinum complex (SiO
2‐MC‐L‐Phe–Pt) has been prepared by a very simple method, and the Pt complex has been found to be able to catalyze the asymmetric hydrogenation of diacetone alcohol to give (R)‐(−)‐2‐methyl‐2,4‐pentandiol at room temperature and under atmospheric hydrogen pressure. The product and optical yields of 2‐methyl‐2,4‐pentandiol amounted to 67.0 and 92.7%, respectively. The product and optical yields were remarkably affected by the Pt content in the complex, the kind of solvent and the reaction temperature. This catalyst was very stable and could be reused several times without any remarkable change in optical catalytic activity. Copyright © 2002 John Wiley & Sons, Ltd.
Synthesis and characterization of a series of novel hyperbranched conjugated polymers
Authors: He Qingguo , Lin Tong , Yang Junlin , Lin Hongzhen , Bai Fenglian 
Published: January 2005

AbstractA series of novel hyperbranched conjugated luminescent polymers with different length of alkyloxy substitution were designed, synthesized, and characterized by FT‐IR, 1H‐NMR, 13C‐NMR and gel permeation chromatography (GPC). Their special photophysical properties can be attributed to their hollowed and twisted structure. Their electrochemical and electroluminescent properties were investigated. The maximum quantum efficiency of light emitting device (LED) made from C1‐HPV is 0.02% at 15 V. Copyright © 2002 John Wiley & Sons, Ltd.
Polymerization of γ‐stearylL‐glutamateN‐carboxyanhydride with multifunctional porphyrin initiator
Authors: Wu Jian , Hu Xiao‐Ping 
Published: January 2005

AbstractRing‐opening polymerization of γ‐stearylL‐glutamateN‐carboxyanhydride (SLGNCA) was performed with a multifunctional porphyrin initiator, meso‐tetrakis(4‐aminophenyl) porphyrin (TAPP), to produce a novel porphyrin‐containing polypeptide. It was found that the yield and intrinsic viscosity of the obtained polymer (PSLG/TAPP) was mainly effected by the initial ratio of SLGNCA to TAPP. The polypeptide was extensively characterized by visible absorption spectroscopy, gel permeation chromatography (GPC),1H‐NMR and IR techniques. It was clarified that the polypeptide has a four‐arm branched structure with a porphyrin core. Copyright © 2002 John Wiley & Sons, Ltd.
Poly(ethylene‐block‐vinylalcohol) film with amphiphilic surface at high temperature
Authors: Shimamura Kaoru , Munesawa Yuhji , Uchida Tetsuya , Hikasa Nobuhiko 
Published: January 2005

AbstractPoly(ethylene‐block‐vinylalcohol) (PE/PVA), which consisted of both hydrophobic and hydrophilic blocks, was prepared by using polyethylene single crystals as starting material. Polyethylene single crystals were reacted with fuming nitric acid resulting in long methylene chains with functional groups such as COOH and NO2 at the ends (the chain lengths were almost the same as the lamellar thickness of polyethylene single crystal). The functionalized methylene chains were allowed to react with 4‐aminostyrene to give corresponding amides, i.e. methylene chains with vinyl groups at the ends (macromer). The macromers were extended by block‐copolymerization with vinyl acetate, then saponified resulting in PE/PVA block copolymer.The block copolymer was molded into sheets which were subsequently heat‐treated in contact with hydrophilic or hydrophobic media. Depending on the media, the sheet surface changed at high temperature reversibly from hydrophilic to hydrophobic and vice versa. The surface property was fixed by quenching because both blocks were able to crystallize. Thus the surface of ­this material can be tailored for various purposes at ­high temperature, and then used in stable condition at room temperature. Copyright © 2002 John Wiley & Sons, Ltd.
Catalytic behavior of silica‐supported methylcellulose–oxalic acid–Pt complex in asymmetric hydrogenation of 2‐butanone and itaconic acid
Authors: Liu Hong‐Wen , Xin Fei , Wu Li‐Min , Huang Mei‐Yu , Jiang Ying‐Yan 
Published: January 2005

AbstractA new silica‐supported biopolymer–oxalic acid–Pt complex was prepared by a simple method. Methylcellulose (mc) reacted with oxalic acid in the presence of silica to give a complex SiO2–MC–(COOH)2 on the surface of silica, then reacted with H2PtCl6·6H2O to form a Pt complex [SiO2–MC–(COOH)2–Pt]. This complex was found to be able to catalyze the asymmetric hydrogenation of 2‐butanone to (S)‐(+)‐2‐butanol and itaconic acid to (S)‐(−)‐methylsuccinic acid, respectively, at room temperature and under 1 atm H2. The experimental results showed that the product and optical yields were remarkably affected by the Pt content in the complex and the catalyst could be reused without any remarkable change in optical catalytic activity. Copyright © 2002 John Wiley & Sons, Ltd.
Asymmetric epoxidation of cinnamyl alcohol catalyzed by silica‐supported casein–Co complex
Authors: Zhang Xi , Han Bing , Hua Yu‐Ning , Huang Mei‐Yu , Jiang Ying‐Yan 
Published: January 2005

AbstractSilica‐supported casein–Co complex (Si‐CA–Co) was prepared from silica, casein and cobalt chloride, and found to be useful as a chiral catalyst for the asymmetric epoxidation of cinnamyl alcohol to (2R,3R)‐(+)‐3‐phenylglycidol at 70 °C and under 1 atmospheric oxygen pressure. When a proper content of cobalt in the Si‐CA–Co complex and suitable reaction conditions were selected, the product and optical yield could be amounted to 70.6 and 92.0%, respectively, and the Si‐CA–Co complex could be reused several times without any remarkable change in the optical catalytic activity. Copyright © 2002 John Wiley & Sons, Ltd.
Fabrication and biocompatibility of cell scaffolds of poly(L‐lactic acid) and poly(L‐lactic‐co‐glycolic acid)
Authors: Shi Guixin , Cai Qing , Wang Changyong , Lu Ning , Wang Shenguo , Bei Jianzhong 
Published: January 2005

AbstractIn this paper, poly(L‐lactic acid) (PLLA) and poly(L‐lactic‐co‐glycolic acid) (PLGA) were synthesized, and the biocompatibility of PLGA(50/50) (molar ratio) was evaluated by observing the tissue response during implanting PLGA(50/50) into rats. After the PLGA(50/50) was implanted into rats for 12 weeks, the lymphocytes and plasma cells became small or disappeared at the muscle tissue of implant site which indicates the biocompatibility of PLGA(50/50) is very good. A series of porous cell scaffolds of PLGA and PLLA were prepared by using a solution‐casting/salt‐leaching technique. An improved method in which a density bottle instead of a graduated cylinder was developed to measure their porosities. It was found that the accuracy and reproducibility of the improved method for measuring porosity are excellent. A porous PLGA(50/50) scaffold was used to study chondrocytes culture. The chondrocytes were proliferated in porous PLGA(50/50) scaffold and the composite cell/PLGA was successfully obtained for cartilage regeneration. Copyright © 2002 John Wiley & Sons, Ltd.
Dependence of morphology on composition of poly(L‐lactide)– poly(ethylene glycol) multiblock copolymers
Authors: Luo Weijun , Li Suming , Bei Jianzhong , Wang Shenguo 
Published: January 2005

AbstractPoly(L‐lactide)–poly(ethylene glycol) (PLA–PEG) multiblock copolymers with predetermined short blocks (Mn ≤ 3000) were synthesized by polyesterification of PLA diols with PEG diacids in the presence of dicyclohexycarbodiimide and dimethylamide pyridine. The molecular structure and morphological features of the resulting copolymers were characterized by analytical techniques, such as gel permeation chromatography (GPC), viscometry,
1H‐NMR, differential scanning calorimetry (DSC), X‐ray diffractometry. The dependence of the morphology on the molecular structure was analyzed in detail. The results indicated that these copolymers were markly improved in practical properties, such as miscibility between the two components, non‐crystallinity. And the regular variation in these respects suggests that the properties of the copolymers can be modulated by adjusting the block length of the two components. Copyright © 2002 John Wiley & Sons, Ltd.
Preparation of temperature‐sensitive polymer films by surface photografting techniques
Authors: Li Bin , Chen Wenguang , Liu Xiaohua , Wang Xiaogong , Zhou Qixiang 
Published: January 2005

AbstractIn this paper, poly(N‐isopropylacrylamide) has been successfully grafted on polypropylene (PP) films by pre‐dipping photografting and dormant radical photografting techniques. It was found that higher grafting yield was achieved by the dormant radical photografting method. An optimum concentration of N‐isopropylacrylamide monomer existed both for the pre‐dipping photografting and for the dormant radical photografting methods. The grafting yield was improved by increasing the UV irradiation time for both methods. Water absorbency of grafted PP films prepared by the two methods was similar and increased nearly linearly with the improvement of grafting yield. At constant temperature and humidity, the grafted PP films lost the absorbed water continually before the water absorbency reached an equilibrium value at this temperature. Copyright © 2002 John Wiley & Sons, Ltd.
A novel polyurethane‐modified poly(N‐isopropylacrylamide) hydrogels
Authors: Liu Xiaohua , Tang Liming , Dai Yu , Wang Xiaogong , Liu Deshan 
Published: January 2005

AbstractTwo kinds of vinylic‐capped urethane acrylate anionomer (UAA) prepolymers were prepared in two steps. pH sensitive hydrogels were synthesized by free radical polymerization of UAA. A series of pH and temperature sensitive hydrogels were prepared by copolymerization of N‐isopropylacrylamide (NIPA) and UAA at various ratios. The influences of pH and temperature on the swelling ratios (SRs) of these hydrogels were investigated in detail. The results indicated that the incorporation of PUAA into the composite hydrogels had little effect on the lower critical solution temperature (LCST) of poly‐(N‐isopropylacrylamide) (PNIPA). The swelling ratios strongly depended on both the composition of the hydrogels and the polymerization temperature. Copyright © 2002 John Wiley & Sons, Ltd.