bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reliability of hand‐held dynamometry in spinal muscular atrophy
Authors: Merlini Luciano , Mazzone Elena Stacy , Solari Alessandra , Morandi Lucia 
Published: October 2002

AbstractWe have assessed the reliability of hand‐held myometry in 33 patients with spinal muscular atrophy (SMA), testing elbow flexion, handgrip, three‐point pinch, knee flexion, knee extension, and foot dorsiflexion, and determining intraclass correlation coefficients (ICC). Interrater reliability was high for upper limbs, with an ICC of 0.92 for three‐point pinch and 0.98 for elbow flexion and grip. For lower limbs interrater reliability was good with ICC >0.85 for all measures except foot dorsiflexion. Test–retest results were excellent with ICC >0.91 in all instances. Hand‐held myometry is easily performed in SMA patients of various ages and muscle strengths, is a reliable measure of limb muscle strength, and can be used in longitudinal studies and clinical trials. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 64–70, 2002
Axonal hyperpolarization associated with acute hypokalemia: Multiple excitability measurements as indicators of the membrane potential of human axons
Authors: Kuwabara Satoshi , Kanai Kazuaki , Sung Jia‐Ying , Ogawara Kazue , Hattori Takamichi , Burke David , Bostock Hugh 
Published: October 2002

AbstractMultiple nerve excitability measurements have been proposed for clinical testing of nerve function, and an important determinant of excitability is membrane potential. We report a patient with acquired hypokalemic paralysis in whom multiple excitability indices (stimulus‐response curve, strength‐duration properties, threshold electrotonus, recovery cycle) were measured during and after an acute hypokalemic attack (serum K+ level, 2.1 mEq/L and 4.5 mEq/L, respectively). During hypokalemia, there was a shift of the stimulus‐response curve to the right, a decrease in strength‐duration time constant, a “fanning‐out” of responses during threshold electrotonus, a reduction in relative refractory period, and an increase in superexcitability; all of these indicate axonal hyperpolarization, presumably due to the K+ equilibrium potential being more negative. These indices returned to normal 20 h later, associated with normalization of the serum K+ level. These results demonstrate that the changes associated with hypokalemic paralysis are not confined to muscle and that axons undergo hyperpolarization in vivo. Multiple excitability measurements can be used as a tool to identify changes in membrane potential of human axons. © 2002 Wiley Periodicals, Inc. Muscle Nerve 26: 283–287, 2002
Managing waiting times of backordered demands in single‐stage (Q, r) inventory systems
Authors: Boyacı Tamer , Gallego Guillermo 
Published: October 2002

AbstractWe present a service constrained (Q, r) model that minimizes expected holding and ordering costs subject to an upper bound on the expected waiting time of demands that are actually backordered. We show that, after optimizing over r, the average cost is quasiconvex in Q for logconcave continuous lead time demand distributions. For logconcave discrete lead time demand distributions we find a single‐pass efficient algorithm based on a novel search stopping criterion. The algorithm also allows for bounds on the variability of the service measure. A brief numerical study indicates how the bounds on service impact the optimal average cost and the optimal (Q, r) choice. The discrete case algorithm can be readily adapted to provide a single pass algorithm for the traditional model that bounds the expected waiting time of all demands (backordered or not). © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 557–573, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10028
Lazy evaluation in penniless propagation over join trees
Authors: Cano Andrés , Moral Serafín , Salmerón Antonio 
Published: October 2002

AbstractIn this paper, we investigate the application of the ideas behind Lazy propagation to the Penniless propagation scheme. Probabilistic potentials attached to the messages and the nodes of the join tree are represented in a factorized way as a product of (approximate) probability trees, and the combination operations are postponed until they are compulsory for the deletion of a variable. We tested two variations of the basic Lazy scheme: One is based on keeping a hash table for the operations with probabilistic potentials that are carried out more than once during the propagation, to avoid repeating computations; the other uses a heuristic method to determine the order of the operations when combining a set of potentials. © 2002 Wiley Periodicals, Inc.
Better approximation ratios for the single‐vehicle scheduling problems on line‐shaped networks
Authors: Karuno Yoshiyuki , Nagamochi Hiroshi , Ibaraki Toshihide 
Published: October 2002

AbstractWe consider two variants of the single‐vehicle scheduling problem on line‐shaped networks. Let L = (V, E) be a line, where V = {v1, v2, … , vn} is a set of n vertices and E = {{vi, vi+1}|i = 1, 2, … , n − 1} is a set of edges. The travel times w(u, v) and w(v, u) are associated with each edge {u, v} ∈ E, and each job, which is also denoted as v and is located at vertex v ∈ V, has release time r(v) and handling time h(v). There is a single vehicle, which is initially situated at v1 ∈ V, and visits all vertices to process the jobs before it returns back to v1. The first problem asks to find an optimal routing schedule of the vehicle that minimizes the completion time. This is NP‐hard [21], and there exists an approximate algorithm with the approximation ratio of 2 [12]. In this paper, we improve this ratio to 1.5. On the other hand, the second problem minimizes the maximum lateness, under the assumption that all release times r(v) are zero, but there are due times d(v) for v ∈ V and d(vn+1) for the vehicle. This problem is also NP‐hard [13]. We improve the previous best‐known approximation ratio of 2, which was obtained in [11], to 1.5. © 2002 Wiley Periodicals, Inc.
Altered odor‐induced expression of c‐fos and arg 3.1 immediate early genes in the olfactory system after familiarization with an odor
Authors: Montag‐Sallaz M. , Buonviso N. 
Published: October 2002

AbstractIn adult rats, repeated exposure to an odorant, in absence of any experimentally delivered reinforcement, leads to a drastic decrease in mitral/tufted (M/T) cell responsiveness, not only for the familiar odor but also for other novel odors. In the present study, using two different and complementary in situ hybridization methods, we analyzed the effect of familiarization with an odorant on c‐fos and arg 3.1 mRNA expression levels, and we examined the odor specificity of this effect. Odor exposure induces a specific increase in c‐fos and arg 3.1 expression in some particular olfactory bulb quadrants. Previous familiarization with the test odor results in a decreased expression of both IEGs in these quadrants, leading to the alteration of the odor‐specific pattern of c‐fos and arg 3.1 expression. In contrast, this odor‐specific pattern is not affected when different odors are used for familiarization and test. Similarly, an odor‐specific familiarization effect leading to a reduced c‐fos and arg 3.1 expression was also detected in the cingulate cortex and in the anterior piriform cortex. These results support our hypothesis that the decrease in M/T cell responsiveness following a preceding familiarization with an odorant may be related to a particular form of synaptic plasticity involving changes at the genomic level, and reveals further insight in olfactory information processing and the cellular mechanisms underlying familiarization in the olfactory system. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 61–72, 2002
Serotonergic sensory‐motor neurons mediate a behavioral response to hypoxia in pond snail embryos
Authors: Kuang Shihuan , Doran Shandra A. , Wilson Richard J. A. , Goss Greg G. , Goldberg Jeffrey I. 
Published: October 2002

AbstractOxygen (O2) is one of the most important environmental factors that affects both physiological processes and development of aerobic animals, yet little is known about the neural mechanism of O2 sensing and adaptive responses to low O2 (hypoxia) during development. In the pond snail, Helisoma trivolvis, the first embryonic neurons (ENC1s) to develop are a pair of serotonergic sensory‐motor cells that regulate a cilia‐driven rotational behavior. Here, we report that the ENC1‐ciliary cell circuit mediates an adaptive behavioral response to hypoxia. Exposure of egg masses to hypoxia elicited a dose‐dependent and reversible acceleration of embryonic rotation that mixed capsular fluid, thereby facilitating O2 diffusion to the embryo. The O2 partial pressures (Po2) for threshold, half‐maximal, and maximal rotational response were 60, 28, and 13 mm Hg, respectively. During hypoxia, embryos relocated to the periphery of the egg masses where higher Po2 levels occurred. Furthermore, intermittent hypoxia treatments induced a sensitization of the rotational response. In isolated ciliary cells, ciliary beating was unaffected by hypoxia, suggesting that in the embryo, O2 sensing occurs upstream of the motile cilia. The rotational response of embryos to hypoxia was attenuated by application of the serotonin receptor antagonist, mianserin, correlated to the development of ENC1‐ciliary cell circuit, and abolished by laser‐ablation of ENC1s. Together, these data suggest that ENC1s are unique oxygen sensors that may provide a good single cell model for the examination of mechanistic, developmental, and evolutionary aspects of O2 sensing. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 73–83, 2002
Development of the specialized AMPA receptors of auditory neurons
Authors: Sugden Steven G. , Zirpel Lance , Dietrich Craig J. , Parks Thomas N. 
Published: October 2002

AbstractAt maturity, the AMPA receptors of auditory neurons exhibit very rapid desensitization kinetics and high permeability to calcium, reflecting the predominance of GluR3 flop and GluR4 flop subunits and the paucity of GluR2. We used mRNA analysis and immunoblotting to contrast the development of AMPA receptor structure in the chick cochlear nucleus [nucleus magnocellularis (NM)] with that of the slowly desensitizing and calcium‐impermeable AMPA receptors of brainstem motor neurons in the nucleus of the glossopharyngeal/vagal nerves. The relative abundance of transcripts for GluRs 1–4 changes substantially in auditory (but not motor) neurons after embryonic day (E)10, with large decreases in GluR2 and increases in GluR3 and GluR4. Relative to the motor neurons, NM neurons show a higher abundance of flop isoforms of GluRs 2–4 at E10, suggesting that auditory neurons are already biased toward expression of flop isoforms before the onset of synaptic function at E11. Immunoreactivities in NM show very distinct developmental patterns from E13 onward: GluR2 declines by >90%, GluR3 increases threefold, and GluR4 remains relatively constant. Our results show that there are a series of critical points during normal development, most occurring after the onset of function, when rapid changes in receptor structure (occurring via both transcriptional and post‐transcriptional control mechanisms) produce the specialized AMPA receptor functions that enable auditory neurons to accurately encode acoustic information. © 2002 Wiley Periodicals, Inc. J Neurobiol 52: 189–202, 2002
Essential boundary condition enforcement in meshless methods: boundary flux collocation method
Authors: Wu Cheng‐Kong C. , Plesha Michael E. 
Published: October 2002

AbstractElement‐free Galerkin (EFG) methods are based on a moving least‐squares (MLS) approximation, which has the property that shape functions do not satisfy the Kronecker delta function at nodal locations, and for this reason imposition of essential boundary conditions is difficult. In this paper, the relationship between corrected collocation and Lagrange multiplier method is revealed, and a new strategy that is accurate and very simple for enforcement of essential boundary conditions is presented. The accuracy and implementation of this new technique is illustrated for one‐dimensional elasticity and two‐dimensional potential field problems. Copyright © 2001 John Wiley & Sons, Ltd.
Elastoplastic dynamic analysis with hybrid stress elements
Authors: Teixeira de Freitas J. A. , Wang Z. M. 
Published: October 2002

AbstractThe stress model of the hybrid finite element formulation is applied to the solution of dynamic elastoplastic structural problems. The stress field is approximated in the domain of the elements and the displacements on its boundary. The displacement, velocity and acceleration approximations in the domain of the element are implicit, in the sense that they result from a combination of the stress estimate with the time integration procedure that ensures that the equilibrium condition is locally satisfied. The finite elements are subdivided in plastic cells where a gradient dependent model is implemented using a hybrid formulation based on the approximation of the plastic parameter and the plastic radiation fields in the domain and on the boundary of the plastic cells, respectively. Generalized variables associated with orthogonal and naturally hierarchical bases are used. The resulting solving systems are symmetric, sparse, p‐adaptive and well suited to parallel processing. The performance of the element is assessed using a representative set of testing problems. Copyright © 2001 John Wiley & Sons, Ltd.
On the optimal cooling strategy for variable‐speed continuous casting
Authors: Constales D. , Kačur J. , Van Keer R. 
Published: October 2002

AbstractIn this paper, we consider the inverse problem of determining the optimal cooling parameters for continuous casting under changing casting speed. We rely on automatic differentiation to support different search methods for the parameter values that will minimize a given cost functional, which can include a variety of criteria: surface temperature evolution and variation, interface position, full solidification point. In the direct problem we use a fixed‐domain transformation to solve the corresponding free‐boundary problem to high accuracy. Numerical experiments are provided to illustrate and support the effectiveness of the present concept. Copyright © 2001 John Wiley & Sons, Ltd.
A procedure for approximation of the error in the EFG method
Authors: Gavete L. , Cuesta J. L. , Ruiz A. 
Published: October 2002

AbstractIn this paper, we present a procedure to estimate the error in elliptic equations using the element‐free Galerkin (EFG) method, whose evaluation is computationally simple and can be readily implemented in existing EFG codes. The estimation of the error works very well in all numerical examples for 2‐D potential problems that are presented here, for regular and irregular clouds of points. Moreover, it was demonstrated that this method is very simple in terms of economy and gives a good performance.The results show that the error in EFG approximation may be estimated via the error estimator described in this paper. The quality of the estimation of the error is demonstrated by numerical examples. The implemented procedure of error approximation allows the global energy norm error to be estimated and also gives a good evaluation of local errors. It can, thus, be combined with a full adaptive process of refinement or, more simply, provide guidance for redesign of cloud of points. Copyright © 2001 John Wiley & Sons, Ltd.
Optimal mesh design for the finite element approximation of reaction–diffusion problems
Authors: Xenophontos Christos 
Published: October 2002

AbstractWe consider the numerical approximation of singularly perturbed problems, and in particular reaction–diffusion problems, by the h version of the finite element method. We present guidelines on how to design non‐uniform meshes both in one and two dimensions that are asymptotically optimal as the meshwidth tends to zero. We also present the results of numerical computations showing that robust, optimal rates can be achieved even in the pre‐asymptotic range. Copyright © 2001 John Wiley & Sons, Ltd.
Adaptive backward Euler time stepping with truncation error control for numerical modelling of unsaturated fluid flow
Authors: Kavetski Dmitri , Binning Philip , Sloan Scott W. 
Published: October 2002

AbstractAn automatic time stepping scheme with embedded error control is developed and applied to the moisture‐based Richards equation. The algorithm is based on the first‐order backward Euler scheme, and uses a numerical estimate of the local truncation error and an efficient time step selector to control the temporal accuracy of the integration. Local extrapolation, equivalent to the use of an unconditionally stable Thomas–Gladwell algorithm, achieves second‐order temporal accuracy at minimal additional costs. The time stepping algorithm also provides accurate initial estimates for the iterative non‐linear solver. Numerical tests confirm the ability of the scheme to automatically optimize the time step size to match a user prescribed temporal error tolerance. An important merit of the proposed method is its conceptual and computational simplicity. It can be directly incorporated into existing or new software based on the backward Euler scheme (currently prevalent in subsurface hydrologic modelling), and markedly improves their performance compared with simple fixed or heuristic time step selection. The generality of the approach also makes possible its use for solving PDEs in other engineering applications, where strong non‐linearity, stability or implementation considerations favour a simple and robust low‐order method, or where there is a legacy of backward Euler codes in current use. Copyright © 2001 John Wiley & Sons, Ltd.
Optimum design of stochastically excited non‐linear dynamic systems without geometric constraints
Authors: Oblak M. M. , Lesnika A. S. , Butinar B. J. 
Published: October 2002

AbstractThis paper presents an efficient procedure for min–max dynamic response optimization of stochastically excited non‐linear systems with multiple time‐delayed inputs. This procedure employs a stochastic linearization technique to overcome system non‐linearity and an auto‐covariance analysis technique to represent the original stochastic mechanical model in a suitable form for optimization. Special attention is given to the sensitivity analysis, due to the complex nature of the problem. Therefore, exact expressions are obtained in a simple form for the evaluation of the required gradients, which greatly improve the stability and efficiency of the optimization algorithm. The numerical results and performance are presented by means of solving two min–max dynamic response optimization problems. Copyright © 2002 John Wiley & Sons, Ltd.
A finite point method for compressible flow
Authors: Löhner Rainald , Sacco Carlos , Oñate Eugenio , Idelsohn Sergio 
Published: October 2002

AbstractA weighted least squares finite point method for compressible flow is formulated. Starting from a global cloud of points, local clouds are constructed using a Delaunay technique with a series of tests for the quality of the resulting approximations. The approximation factors for the gradient and the Laplacian of the resulting local clouds are used to derive an edge‐based solver that works with approximate Riemann solvers. The results obtained show accuracy comparable to equivalent mesh‐based finite volume or finite element techniques, making the present finite point method competitive. Copyright © 2001 John Wiley & Sons, Ltd.
High‐order finite volume schemes for the advection–diffusion equation
Authors: Hernández J. A. 
Published: October 2002

AbstractA high‐order finite volume method based on piecewise interpolant polynomials is proposed to discretize spatially the one‐dimensional and two‐dimensional advection–diffusion equation. Evolution equations for the mean values of each control volume are integrated in time by a classical fourth‐order Runge–Kutta. Since our work focuses on the behaviour of the spatial discretization, the time step is chosen small enough to neglect the time integration error.Two‐dimensional interpolants are built by means of one‐dimensional interpolants. It is shown that when the degree of the one‐dimensional interpolant q is odd, the proper selection of a fixed stencil gives rise to centred schemes of order q+1. In order not to lose precision due to the change of stencil near boundaries, the degree of the interpolants close to boundaries is raised to q+1. Four test cases with small values of diffusion are integrated with high‐order methods. It is shown that the spatial discretization of the advection–diffusion equation with periodic boundary conditions leads to normal discretization matrices, and asymptotic stability must be assured to bound the spatial discretization error. Once the asymptotic stability is assured by means of the spectra of the discretization matrix, the spatial error is of the order of the truncation error. However, it is shown that the discretization of the advection–diffusion equation with arbitrary boundary conditions gives rise to non‐normal matrices. If asymptotic stability is assured, the spatial order of steady solutions is of the order of the truncation error. But, for transient processes, the order of the spatial error is determined by both the truncation error and the norm of the exponential matrix of the spatial discretization. The use of the pseudospectra of the discretization matrix is proposed as a valuable tool to analyse the transient error of the numerical solution. Copyright © 2001 John Wiley & Sons, Ltd.
A new class of Cn interpolations and its application to the finite element method
Authors: Hashemolhosseini H. , Sadati N. , Farzin M. 
Published: October 2002

AbstractA new class of Cn continuous interpolations is presented. These interpolations consist of two or more Lagrangian interpolations blended by pseudo Hermitian interpolation. Using this class of interpolations a new Cn family of displacement type elements is developed. The properties of this new family of elements such as their precision and their superconvergent points are discussed. Some solutions to the corner elements problem and implication of different boundary conditions are proposed. Using this new kind of element, several examples of deflection of elastic beams and plates are treated, the results of which are encouraging. Copyright © 2001 John Wiley & Sons, Ltd.
Three‐dimensional finite element solution of gas‐assisted injection moulding
Authors: Ilinca F. , Hétu J.‐F. 
Published: October 2002

AbstractThis paper presents a finite element algorithm for solving gas‐assisted injection moulding problems. The filling material is considered incompressible and has temperature and shear rate dependent viscosity. The solution of the three‐dimensional (3D) equations modelling the momentum, mass and energy conservation is coupled with two front‐tracking equations, which are solved for the polymer/air and gas/polymer interfaces. The performances of the proposed procedure are quantified by solving the gas‐assisted injection problem on a thin plate with a flow channel. Solutions are shown for different polymer/gas ratios injected. The effect of the melt temperature, gas pressure and gas injection delay, on the solution behaviour is also investigated. The approach is then applied to a thick 3D part. Published in 2001 by John Wiley & Sons, Ltd.