bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of brain‐derived neurotrophic factor in wobbler mouse motor neuron disease
Authors: Tsuzaka Kazufumi , Ishiyama Takeo , Pioro Erik P. , Mitsumoto Hiroshi 
Published: August 2002

AbstractBrain‐derived neurotrophic factor (BDNF) is neuroprotective for motoneurons undergoing degeneration, including those in natural motor neuron disease (MND) in wobbler mice. To assess the role of BDNF in this model of MND, endogenous BDNF immunoreactivity was analyzed by semiquantitative video‐image analysis. Affected cervical spinal cord motoneurons had significantly greater BDNF immunoreactivity compared to motoneurons of healthy littermates (P = 0.01) and affected lumbar spinal cord motoneurons (P = 0.008 at age 4 weeks; P = 0.005 at age 8 weeks). Neuronal nitric oxide synthase (n‐NOS) immunocytochemistry revealed increased immunoreactivity in the affected cervical spinal cord motoneurons. Exogenous BDNF treatment partially inhibited the increased NOS activity, as quantitatively measured by nicotinamide adenine dinucleotide phosphate diaphorase (NADPH‐d) histochemistry. The mean number of NADPH‐d+ motoneurons in the cervical anterior horn decreased from 3.5 ± 1.2 to 1.5 ± 1.2 (P = 0.002). The increase in endogenous BDNF immunoreactivity in the affected spinal cord may be compensatory in diseased motoneurons, yet it appears to still be inadequate because exogenous BDNF treatment is required to suppress increased NOS activity in degenerating motoneurons. Our study indicates that BDNF is important in halting nitric oxide (NO)‐mediated motor neuron degeneration, which has potential implications for the treatment of neurodegenerative disorders. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 474–480, 2001.
Condition for the onset of bifurcation in en echelon crack arrays
Authors: Chau K. T. , Wang G. S. 
Published: August 2002

AbstractEmergence and evolution of en echelon crack arrays play an essential role in the failure of geomaterials, regardless of the scale of deformation. This paper derives analytically an approximation for the critical crack size/spacing ratio at which a uniformly growing en echelon crack array yields to a non‐uniform growing pattern of crack growth. Numerical results show that the critical crack size/spacing ratio λcr (=a/d where a is the half crack length and d is the distance between the centres of two adjacent cracks) depends on the orientation of the crack array ϕ, the number of cracks N in the array, as well as the loading conditions. In general, λcr decreases with N, but depends non‐linearly on ϕ. When en echelon crack arrays are under far‐field shearing along the direction of the crack array, our prediction for λcr is about 0.5715, comparing to the experimental observation of about 0.5. For rock joints containing en echelon cracks, the interpreted critical crack size at the onset of the alternating evolution of crack growth are 0.66 and 0.89 for ϕ=26 and 16°, comparing to our predictions of 0.5695 and 0.6112, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Chemically induced deformation of a porous layer coupled with advective–dispersive transport. Analytical solutions
Authors: Kaczmarek Mariusz 
Published: August 2002

AbstractIn this paper a chemically induced deformation of porous material taking place during advective–dispersive transport of a chemical is considered. Linearized governing equations are derived and analytical solutions of 2 one‐dimensional problems for a homogeneous layer with drained boundaries are developed. Numerical results for a particular clayey material and a chemical migrating through the layer showing distributions of concentration of chemical, changes in porosity of the material and pore fluid pressure, and evolution of settlement of the layer as functions of time are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Minimax inverse problems of minimum cuts
Authors: Shigeno Maiko 
Published: August 2002

AbstractLet G = (N, A) be a directed graph of n nodes and m arcs with an upper bound u ∈ ℤA. Given an s—t cut S0, the minimax inverse minimum‐cut problem (MIMC) is to find a modified upper bound ũ ∈ ℝA such that S0 is a minimum cut for ũ and max {|uij − ũij‖(i, j) ∈ A} is minimum. This paper shows that the MIMC is closely related to the maximum mean‐cut problem. By applying a parametric search for maximum mean‐cut problems, the MIMC can be solved as a sequence of O(n) minimum s—t cut problems or in O(min {n2/3, m1/2}m log (n2/m) log n log (nU)) time, where U is the maximum value of u. © 2002 John Wiley & Sons, Inc.
Partial line directed hypergraphs
Authors: Ferrero Daniela , Padró Carles 
Published: August 2002

AbstractThe partial line digraph technique was introduced in [7] in order to construct digraphs with a minimum diameter, maximum connectivity, and good expandability. To find a new method to construct directed hypergraphs with a minimum diameter, we present in this paper an adaptation of that technique to directed hypergraphs. Directed hypergraphs are used as models for interconnection networks whose vertices are linked by directed buses. The connectivity and expandability of partial line directed hypergraphs are studied. Besides, we prove a conjecture by J‐C. Bermond and F. Ergincan about the characterization of line directed hypergraphs. © 2002 Wiley Periodicals, Inc.
Balanced network flows. VI. Polyhedral descriptions
Authors: Fremuth‐Paeger Christian , Jungnickel Dieter 
Published: August 2002

AbstractThis paper discusses the balanced circulation polytope, that is, the convex hull of balanced circulations of a given balanced flow network. The LP description of this polytope is the LP description of ordinary circulations plus some odd‐set constraints. The paper starts with an exposition of several classes of odd‐set inequalities. These inequalities are described in terms of balanced network flows as well as matchings and put into relation to each other. Step by step, the problem of finding a cost minimum balanced circulation can be reduced to the b‐matching problem. We present an LP characterization of the b‐matching polytope by blossom inequalities. With a moderate effort, these odd sets are lifted to the setting of balanced‐network flows. We finish with the dualization of the derived LP formulation, an introduction of reduced‐cost labels, and a corresponding optimality condition. © 2001 John Wiley & Sons, Inc.
The ultracenter and central fringe of a graph
Authors: Chartrand Gary , Novotny Karen S. , Winters Steven J. 
Published: August 2002

AbstractThe central distance of a central vertex v in a connected graph G with rad G < diam G is the largest nonnegative integer n such that whenever x is a vertex with d(v, x) ≤ n then x is also a central vertex. The subgraph induced by those central vertices of maximum central distance is the ultracenter of G. The subgraph induced by the central vertices having central distance 0 is the central fringe of G. For a given graph G, the smallest order of a connected graph H is determined whose ultracenter is isomorphic to G but whose center is not G. For a given graph F, we determine the smallest order of a connected graph H whose central fringe is isomorphic to G but whose center is not G. © 2001 John Wiley & Sons, Inc.
Local search with perturbations for the prize‐collecting Steiner tree problem in graphs
Authors: Canuto S. A. , Resende M. G. C. , Ribeiro C. C. 
Published: August 2002

AbstractGiven an undirected graph with prizes associated with its nodes and weights associated with its edges, the prize‐collecting Steiner tree problem consists of finding a subtree of this graph which minimizes the sum of the weights of its edges plus the prizes of the nodes not spanned. In this paper, we describe a multistart local search algorithm for the prize‐collecting Steiner tree problem, based on the generation of initial solutions by a primal‐dual algorithm using perturbed node prizes. Path‐relinking is used to improve the solutions found by local search and variable neighborhood search is used as a post‐optimization procedure. Computational experiments involving different algorithm variants are reported. Our results show that the local search with perturbations approach found optimal solutions on nearly all of the instances tested. © 2001 John Wiley & Sons, Inc.
Solving the minimum‐weighted coloring problem
Authors: Caramia Massimiliano , Dell'Olmo Paolo 
Published: August 2002

AbstractWeighted coloring is a generalization of the well‐known vertex (unweighted) coloring for which a number of exact algorithms have been presented in the literature. We are not aware of any optimal method specifically designed for the minimum‐weighted coloring problem on arbitrary graphs. Only a few heuristics have been developed with the goal of finding tighter upper bounds for the maximum‐weighted clique problem. Moreover, as shown in the paper, a straightforward reduction of a weighted instance into an unweighted one permits us to solve only very small instances. In this paper, we present a branch‐and‐bound algorithm for the weighted case capable of solving random graphs of up to 90 vertices for any edge density with integer weights uniformly drawn from the range [1, …,10]. Likewise, we have used properly modified benchmark instances borrowed from vertex coloring as a further test bed for our algorithm. © 2001 John Wiley & Sons, Inc.
Targeted expression of tetanus neurotoxin interferes with behavioral responses to sensory input in Drosophila
Authors: Keller Andreas , Sweeney Sean T. , Zars Troy , O'Kane Cahir J. , Heisenberg Martin 
Published: August 2002

AbstractTargeted inactivation of neurons by expression of toxic gene products is a useful tool to assign behavioral functions to specific neurons or brain structures. Of a variety of toxic gene products tested, tetanus neurotoxin light chain (TNT) has the least severe side effects and can completely block chemical synapses. By using the GAL4 system to drive TNT expression in a subset of chemo‐ and mechanosensory neurons, we detected walking and flight defects consistent with blocking of relevant sensory information. We also found, for the first time, an olfactory behavioral phenotype associated with blocking of a specific subset of antennal chemoreceptors. Similar behavioral experiments with GAL4 lines expressing in different subsets of antennal chemoreceptors should contribute to an understanding of olfactory coding in Drosophila. To increase the utility of the GAL4 system for such purposes, we have designed an inducible system that allows us to circumvent lethality caused by TNT expression during early development. © 2002 Wiley Periodicals, Inc. J Neurobiol 50: 221–233, 2002; DOI 10.1002/neu.10029
On parallel solution of linear elasticity problems. Part II: Methods and some computer experiments
Authors: Gustafsson I. , Lindskog G. 
Published: August 2002

AbstractThis is the second part of a trilogy on parallel solution of the linear elasticity problem. We consider the plain case of the problem with isotropic material, including discontinuous coefficients, and with homogeneous Dirichlet boundary condition. The discretized problem is solved by the preconditioned conjugate gradient (pcg) method.In the first part of the trilogy block‐diagonal preconditioners based on the separate displacement component part of the elasticity equations were analysed. The preconditioning systems were solved by the pcg‐method, i.e. inner iterations were performed. As preconditioner, we used modified incomplete factorization MIC(0), where possibly the element matrices were modified in order to give M‐matrices, i.e. in order to guarantee the existence of the MIC(0) factorization.In the present paper, the second part, full block incomplete factorization preconditioners are presented and analysed. In order to avoid inner/outer iterations we also study a variant of the block‐diagonal method and of the full block method, where the matrices of the inner systems are just replaced by their MIC(0)‐factors. A comparison is made between the various methods with respect to rate of convergence and work per unknown. The fastest methods are implemented by message passing utilizing the MPI system.In the third part of the trilogy, we will focus on the use of higher‐order finite elements. Copyright © 2002 John Wiley & Sons, Ltd.
Combined hybrid approach to finite element schemes of high performance
Authors: Zhou T.‐X. , Nie Y.‐F. 
Published: August 2002

AbstractBased on a combination of Hellinger–Reissner principle with its dual, a mixed/hybrid method of non‐saddle point type has been presented in the previous papers. In the paper, an application of the method to two‐dimensional elasticity problems is considered in a manner of combination of mathematical analysis with numerical investigation. How to construct a combined hybrid scheme of high performance is discussed, and several four‐node quadrilateral CH‐elements are systematically verified. In brief, this paper shows that for the hybrid element scheme, the energy compatibility condition, introduced in Zhou (Combined hybrid finite element method without requirement for Babuska‐Brezzi condition, to appear) is the ultimate key to the achievement of high performance. Copyright © 2001 John Wiley & Sons, Ltd.
Accuracy of Galerkin finite elements for groundwater flow simulations in two and three‐dimensional triangulations
Authors: Cordes Christian , Putti Mario 
Published: August 2002

AbstractIn standard finite element simulations of groundwater flow the correspondence between hydraulic head gradients and groundwater fluxes is represented by the stiffness matrix. In two‐dimensional problems the use of linear triangular elements on Delaunay triangulations guarantees a stiffness matrix of type M. This implies that the local numerical fluxes are physically consistent with Darcy's law. This condition is fundamental to avoid the occurrence of local maxima or minima, and is of crucial importance when the calculated flow field is used in contaminant transport simulations or pathline evaluation. In three spatial dimensions, the linear Galerkin approach on tetrahedra does not lead to M‐matrices even on Delaunay meshes. By interpretation of the Galerkin approach as a subdomain collocation scheme, we develop a new approach (OSC, orthogonal subdomain collocation) that is shown to produce M‐matrices in three‐dimensional Delaunay triangulations. In case of heterogeneous and anisotropic coefficients, extra mesh properties required for M‐stiffness matrices will also be discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Numerical integration of lattice rotation in polycrystal plasticity
Authors: Kok S. , Beaudoin A. J. , Tortorelli D. A. 
Published: August 2002

AbstractA numerical algorithm to calculate the lattice rotation in polycrystal plasticity models, that is based on the analytical integration of the lattice rotation update equation, is presented. Implicit and explicit implementations perform equally well and are superior to the currently used numerical integration schemes. Copyright © 2001 John Wiley & Sons, Ltd.
Individual differences in the induction of sensitisation or tolerance to the motor effects of morphine in mice
Authors: Manzanedo Carmen , Aguilar María A. , Rodriguez‐Arias Marta , Miñarro José 
Published: August 2002

AbstractAcute morphine administration produces hyperactivity in most strains of mice and some studies indicate that repeated treatment can induce a potentiation of this effect (sensitisation). With the object of determining whether the hyperactivity induced by morphine in OF1 mice shows sensitisation after repeated administration, we tested the effect of the pre‐exposure to six daily injections of morphine on the subsequent hyperactivity induced by the same dose of this drug. Animals were treated with 40 mg/kg of morphine for seven days. After the last injection they were tested in an actimeter at different points at time (15, 30, 45 and 60 min). This repeated schedule of treatment produced sensitisation in some animals but tolerance in others. These results suggest the existence of great individual differences in the motor effects of repeated morphine administration and that the development of sensitisation and tolerance in outbred mice may be subjected to genetic variation.
A priori error estimates for interior penalty versions of the local discontinuous Galerkin method applied to transport equations
Authors: Dawson Clint , Proft Jennifer 
Published: August 2002

AbstractThe local discontinuous Galerkin method has been developed recently by Cockburn and Shu for convection‐dominated convection‐diffusion equations. In this article, we consider versions of this method with interior penalties for the numerical solution of transport equations, and derive a priori error estimates. We consider two interior penalty methods, one that penalizes jumps in the solution across interelement boundaries, and another that also penalizes jumps in the diffusive flux across such boundaries. For the first penalty method, we demonstrate convergence of order k in the L∞(L2) norm when polynomials of minimal degree k are used, and for the second penalty method, we demonstrate convergence of order k+1/2. Through a parabolic lift argument, we show improved convergence of order k+1/2 (k+1) in the L2(L2) norm for the first penalty method with a penalty parameter of order one (h−1). © 2001 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 17: 545–564, 2001
Urban small vertebrate taphonomy: a case study from Anglo–Scandinavian York
Authors: Piper P.J. , O'Connor T.P. 
Published: August 2002

AbstractSampling of deposits at the Queens Hotel site, York, produced a substantial number of small terrestrial vertebrate remains from the Anglo–Scandinavian features. By studying bone surface modification, fragmentation and skeletal completeness as taphonomic indicators, it was possible to demonstrate that the assemblage had resulted from two very different modes of accumulation and deposition. Refuse pits situated within the boundaries of the tenements had acted as accumulators of the fragmented and abraded small mammal and amphibian bones that existed as a sub‐surface death assemblage within the local environment. In contrast, the excellent preservation and skeletal completeness of numerous frogs recovered from the basal fill of a wooden well could be accounted for by their direct entry into the burial environment as a result of pit‐fall trapping. This paper also discusses the implications that the temporal and spatial variation in deposition demonstrated by the micro‐faunal remains has for the reconstruction of local ecological and environmental conditions within this site, and for other such sites. Copyright © 2001 John Wiley & Sons, Ltd.
Microscopic configurations on the bare‐bone surfaces of mammalian synovial joints
Authors: Miles A.E.W. 
Published: August 2002

AbstractThe smoothness characteristic of synovial joint surfaces of bare bones is shown to be an illusion; low‐power microscopy of young adult human bones from interments revealed, on the surfaces of a variety of synovial joints, a system of basically hemispherical elevations, often united as short chains or groups. This system was also found on joints of a variety of species of six mammalian orders. Under the higher magnification of scanning electron microscopy (SEM), many elevations had a pit at their summits. The bare‐bone surfaces of synovial joints have a thin covering of mineralized cartilage, including its mineralizing‐front, which survives taphonomic processes, as well as the preparative procedures used in the study of articular surfaces. In its formative phase, the front has the chondrocyte–columnar structure of cartilage. It is postulated here that the newly‐discovered elevations arise when cartilage formation is ceasing, or becoming dormant, and that each column‐unit produces a globular mineralized mass, often with a pit which had accommodated a chondrocyte. These masses may incorporate the fibre systems of the unmineralized cartilage and aid in its attachment to the bony surface. Copyright © 2001 John Wiley & Sons, Ltd.
Troubles, partnerships and possibilities: a study of the Making Belfast Work development initiative in Northern Ireland
Authors: Hodgett Susan , Johnson David 
Published: August 2002

AbstractThis article examines the theory and operation of development partnerships through an analytical study of the Making Belfast Work (MBW) Initiative in Northern Ireland. This initiative of the Northern Ireland Department of the Environment contributed to the building of the current Northern Irish Peace Process. It illustrates the difficulties faced by a government in engaging in socio‐economic development in one of the world's most difficult policy environments. The history of the MBW initiative also provides insight into the interaction of two contending models for organizing European Society, namely ‘Regulated Capitalism’ and ‘Neoliberalism’ and the relationship of these models to partnership theory. This study argues that motivations for the development of partnerships in Belfast defy easy theoretical classification; yet empirical evidence suggests that a twin‐track approach—one from above, the European Union; and one from below, of indigenous policy evolution—have together through policy diffusion made MBW a leading pioneer in partnership theory and practice. The article discusses the literature on partnership within New Public Administration outlining ideas on various classifications of partnerships operative in the public sector. Particular attention is paid to how partnerships of societal actors and government can effectively involve the local community through community development approaches. Copyright © 2001 John Wiley & Sons, Ltd.
Finding energy in strategic project management: an essay in honour of Dean Fang
Authors: Curtis Donald 
Published: August 2002

AbstractA development project is an intervention that is designed to makes things better in a particular context or situation. It is always a problem to know what to do for the best. The Logical Framework, evaluated in this journal last year (Gasper, 2000), is a project‐planning and management technique widely applied by multilateral as well as bilateral donor agencies in international development work. It was designed to prevent project managers from simply offering to do what they had always done before and instead to think strategically about cause and effect in context. The present article respects this logical approach but focuses attention upon context. Context is considered in the right‐hand column of a Log Frame. The article seeks inspiration in ancient Chinese concepts of energy: Yin–Yang and Wu–Wei. The search is for a form of project management that minimizes energy consumption in its own internal processes and maximizes energy release in the context that the project seeks to transform. Context has to be examined for opportunities rather than constraints. The article advocates management by being a still presence, as against management by rushing about. It borrows the old‐fashioned idea about being a catalyst and validates the now fashionable concepts of enabling and empowering. It also rediscovers at least some virtue in the Blueprint Project. The article seeks to be practical. A management development project in the Northern Cape Province of South Africa provides some illustrations and an incomplete example of what might be entailed if energy is brought into the equations of project management. Copyright © 2001 John Wiley & Sons, Ltd.