bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of dynamic thigh muscle contraction by electrical stimulation of the posterior cruciate ligament in humans
Authors: Fischer‐Rasmussen Torsten , Krogsgaard Michael , Jensen Dennis Bo , Dyhre‐Poulsen Poul 
Published: August 2002

AbstractWe investigated the influence of electrical stimulation of the posterior cruciate ligament (PCL) on the motoneuron pool of the thigh muscle during voluntary static and dynamic muscle contraction. The study group comprised nine young men with no history of injury to the knee joints. Multistranded Teflon‐insulated stainless‐steel wires were inserted into the PCL guided by ultrasound. In three subjects wires were also inserted into the fat pad of the knee. The PCL was electrically stimulated during static, concentric, or eccentric muscle contraction with a constant load of 20% of the maximal voluntary contraction of either the quadriceps or the hamstrings. Electromyographic signals were recorded with bipolar surface electrodes placed over the vastus medialis, rectus femoris, vastus lateralis, biceps femoris caput longum, and semitendinosus muscles. The stimuli consisted of four pulses delivered at 200 HZ; the stimulus amplitude was two to three times the sensory threshold. The electrical stimulation of the PCL inhibited the ongoing muscle activity in both the quadriceps and hamstrings with latencies of 114–150 ms and 99–130 ms, respectively. Stimulation of the fat pad of the knee did not influence the muscle activity. The study suggests that the mechanoreceptors in the PCL are involved in controlling muscle activity during both static and active muscle contractions. The relative long latency of the reflex makes it unlikely that it can serve as a directly protective reflex for the cruciate ligaments. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1482–1488, 2001
Scaling of geological discontinuity normal load–deformation response using fractal geometry
Authors: Plesha Michael E. , Ni Demai 
Published: August 2002

AbstractThe mechanical behaviour of discontinuities in rock, such as joints, is known to be size‐dependent. It is also suspected that the behaviour of larger size features, such as faults, is also size‐dependent. This size dependence has serious implications for performing numerical response simulations of geological media. In this paper, we develop a new mathematical theory for scaling of one particular discontinuity property, namely the interface normal stiffness. To accomplish this, we idealize an interface to have fractal geometry, and we develop analytical relations which show that the interface normal stiffness, which is commonly thought to be a size‐independent property, is in fact a size‐dependent property and has fractal characteristics that may be exploited to develop a fundamental theory for scaling. Copyright © 2001 John Wiley & Sons, Ltd.
A fractal comminution approach to evaluate the drilling energy dissipation
Authors: Carpinteri Alberto , Pugno Nicola 
Published: August 2002

AbstractThe drilling comminution is theoretically and experimentally analysed by a fractal approach. An extension of the Third Comminution Theory is developed to evaluate the energy dissipation in the process: it occurs in a fractal domain intermediate between a surface and a volume. The theoretical assumption of a material ‘quantum’ is experimentally observed. The experimental fragment analysis evidences the characteristic size of separation between primary cutting and secondary milling. A global power balance for the drilling process is also presented and permits the prediction of drilling velocity. It shows also how the dissipation energy density (drilling strength) is not a constant parameter, but decreases considerably with the size scale. Copyright © 2002 John Wiley & Sons, Ltd.
Optimal switchover times between two activities utilizing the same resource
Authors: Karakul M. , Parlar M. 
Published: August 2002

AbstractThe “gold‐mining” decision problem is concerned with the efficient utilization of a delicate mining equipment working in a number of different mines. Richard Bellman was the first to consider this type of a problem. The solution found by Bellman for the finite‐horizon, continuous‐time version of the problem with two mines is not overly realistic since he assumed that fractional parts of the same mining equipment could be used in different mines and this fraction could change instantaneously. In this paper, we provide some extensions to this model in order to produce more operational and realistic solutions. Our first model is concerned with developing an operational policy where the equipment may be switched from one mine to the other at most once during a finite horizon. In the next extension we incorporate a cost component in the objective function and assume that the horizon length is not fixed but it is the second decision variable. Structural properties of the optimal solutions are obtained using nonlinear programming. Each model and its solution is illustrated with a numerical example. The models developed here may have potential applications in other areas including production of items requiring the same machine or choosing a sequence of activities requiring the same resource. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 186–203, 2002; DOI 10.1002/nav.10008
Dynamic pricing and inventory control with learning
Authors: Petruzzi Nicholas C. , Dada Maqbool 
Published: August 2002

AbstractOptimal operating policies and corresponding managerial insight are developed for the decision problem of coordinating supply and demand when (i) both supply and demand can be influenced by the decision maker and (ii) learning is pursued. In particular, we determine optimal stocking and pricing policies over time when a given market parameter of the demand process, though fixed, initially is unknown. Because of the initially unknown market parameter, the decision maker begins the problem horizon with a subjective probability distribution associated with demand. Learning occurs as the firm monitors the market's response to its decisions and then updates its characterization of the demand function. Of primary interest is the effect of censored data since a firm's observations often are restricted to sales. We find that the first‐period optimal selling price increases with the length of the problem horizon. However, for a given problem horizon, prices can rise or fall over time, depending on how the scale parameter influences demand. Further results include the characterization of the optimal stocking quantity decision and a computationally viable algorithm. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 303–325, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10013
On the use of second‐order descriptors to predict queueing behavior of MAPs
Authors: Andersen Allan T. , Nielsen Bo Friis 
Published: August 2002

AbstractThe contributions of this paper are the following: We derive a formula for the IDI (Index of Dispersion for Intervals) for the Markovian Arrival Process (MAP). We show that two‐state MAPs with identical fundamental rate, IDI and IDC (Index of Dispersion for Counts), define interval stationary point processes that are stochastically equivalent; this is true for the time stationary point processes they define too. Special cases of the two‐state MAP are frequently used as source models in the literature. The result shows that, fitting to the rate, IDC and IDI of a source completely determine the interval stationary and time stationary behavior of the two‐state model. We give various illustrative numerical examples on the merits in predicting queueing behavior on the basis of first‐ and second‐order descriptors by considering queueing behavior of MAPs with constant fundamental rate and IDC, respectively, constant fundamental rate and IDI. Disturbing results are presented on how different the queueing behavior can be with these descriptors fixed. Even MAPs with NO correlations in the counting process, i.e., IDC(t) = 1 are shown to have very different queueing behavior. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 391–409, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10015
Rendezvous search when marks are left at the starting points
Authors: Baston Vic , Gal Shmuel 
Published: August 2002

AbstractLeaving marks at the starting points in a rendezvous search problem may provide the players with important information. Many of the standard rendezvous search problems are investigated under this new framework which we call markstart rendezvous search. Somewhat surprisingly, the relative difficulties of analysing problems in the two scenarios differ from problem to problem. Symmetric rendezvous on the line seems to be more tractable in the new setting whereas asymmetric rendezvous on the line when the initial distance is chosen by means of a convex distribution appears easier to analyse in the original setting. Results are also obtained for markstart rendezvous on complete graphs and on the line when the players' initial distance is given by an unknown probability distribution. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 722–731, 2001
Stochastic allocation of inspection capacity to competitive processes
Authors: Jang Wooseung , Shanthikumar J. George 
Published: August 2002

AbstractOptimal allocation and control of limited inspection capacity for multiple production processes are considered. The production processes, which operate independently but share inspection capacity, are subject to random failures and are partially observed through inspection. This study proposes an approach of stochastic allocation, using a Markov decision process, to minimize expected total discounted cost over an infinite time horizon. Both an optimal model and a disaggregate approximation model are introduced. The study provides some structural results and establishes that the control policy is of a threshold type. Numerical experiments demonstrate a significantly decreased amount of computational time required for the disaggregate approach when compared to the optimal solution, while generating very good control policies. © 2002 John Wiley & Sons, Inc. Naval Research Logistics, 49: 78–94, 2002; DOI 10.1002/nav.1049
High‐resolution imaging demonstrates dynein‐based vesicular transport of activated trk receptors
Authors: Bhattacharyya Anita , Watson Fiona L. , Pomeroy Scott L. , Zhang Yanzhen Z. , Stiles Charles D. , Segal Rosalind A. 
Published: August 2002

AbstractTarget‐derived neurotrophins signal from nerve endings to the cell body to influence cellular and nuclear responses. The retrograde signal is conveyed by neurotrophin receptors (Trks) themselves. To accomplish this, activated Trks may physically relocalize from nerve endings to the cell bodies. However, alternative signaling mechanisms may also be used. To identify the vehicle wherein the activated Trks are located and transported, and to identify associated motor proteins that would facilitate transport, we use activation‐state specific antibodies in concert with immunoelectron microscopy and deconvolution microscopy. We show that the activated Trks within rat sciatic nerve axons are preferentially localized to coated and uncoated vesicles. These vesicles are moving in a retrograde direction and so accumulate distal to a ligation site. The P‐Trk containing vesicles, in turn, colocalize with dynein components, and not with kinesins. Collectively, these results indicate activated Trk within axons travel in vesicles and dynein is the motor that drives these vesicles towards the cell bodies. © 2002 Wiley Periodicals, Inc. J Neurobiol 51: 302–312, 2002
Expression and function of Xenopus laevis p75NTR suggest evolution of developmental regulatory mechanisms
Authors: Hutson Lara D. , Bothwell Mark 
Published: August 2002

AbstractNeurotrophins signal through two different classes of receptors, members of the trk family of receptor tyrosine kinases, and p75 neurotrophin receptor (p75NTR), a member of the tumor necrosis factor receptor family. While neurotrophin binding to trks results in, among other things, increased cell survival, p75NTR has enigmatically been implicated in promoting both survival and cell death. Which of these two signals p75NTR imparts depends on the specific cellular context. Xenopus laevis is an excellent system in which to study p75NTR function in vivo because of its amenability to experimental manipulation. We therefore cloned partial cDNAs of two p75NTR genes from Xenopus, which we have termed p75NTRa and p75NTRb. We then cloned two different cDNAs, both of which encompass the full coding region of p75NTRa. Early in development both p75NTRa and p75NTRb are expressed in developing cranial ganglia and presumptive spinal sensory neurons, similar to what is observed in other species. Later, p75NTRa expression largely continues to parallel p75NTR expression in other species. However, Xenopus p75NTRa is additionally expressed in the neuroepithelium of the anterior telencephalon, all layers of the retina including the photoreceptor layer, and functioning axial skeletal muscle. Finally, misexpression of full length p75NTR and each of two truncated mutants in developing retina reveal that p75NTR probably signals for cell survival in this system. This result contrasts with the reported role of p75NTR in developing retinae of other species, and the possible implications of this difference are discussed. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 79–98, 2001
Stable factorization for Hankel and Hankel‐like matrices
Authors: Olshevsky Vadim , Stewart Michael 
Published: August 2002

AbstractThis paper gives fast O(n2) algorithms for the factorization of positive‐definite and indefinite Hankel matrices. The algorithms are based on the concept of displacement structure and are valid for the more general class of Hankel‐like matrices. The positive‐definite algorithm is proven to be backward stable. The indefinite algorithm uses a look‐ahead step that is naturally suggested by displacement approach. Our error analysis suggests a new criterion for the size of the look‐ahead step and our numerical experiments suggest that the use of the new criterion allows us to ensure numerical stability in practice. Copyright © 2001 John Wiley & Sons, Ltd.
Initial strain formulation without internal cells for elastoplastic analysis by triple‐reciprocity BEM
Authors: Ochiai Yoshihiro , Kobayashi Tadashi 
Published: August 2002

AbstractIn general, internal cells are required to solve elastoplasticity problems using a conventional boundary element method (BEM). However, in this case, the merit of BEM, which is the easy method of preparation of data, is lost. The conventional multiple‐reciprocity boundary element method (MRBEM) cannot be used to solve the elastoplasticity problems because the distribution of initial strain or initial stress cannot be determined analytically. In this paper, we show that two‐dimensional elastoplasticity problems can be solved without the use of internal cells, by using the triple‐reciprocity boundary element method. An initial strain formulation is adopted and the initial strain distribution is interpolated using boundary integral equations. A new computer programme was developed and applied to several problems. Copyright © 2001 John Wiley & Sons, Ltd.
The efficiency of the p‐version finite element method in a distributed computing environment
Authors: Rank Ernst , Rücker Martin , Düster Alexander , Bröker Henrike 
Published: August 2002

AbstractThe p‐version of the finite element method is now commonly considered to be a very accurate discretization method for linear elliptic partial differential equations, but many researchers still doubt the efficiency of this method, when compared to the classical h‐version and applied to more complex problems. This paper will first discuss some general considerations about the efficiency of a numerical method and then present results on an evaluation of the p‐version. It will be shown, that there are many special techniques being applicable to the p‐version, yielding a well‐performing and robust method. This will be demonstrated on several examples, including non‐linear problems and a parallel implementation on a workstation cluster. A client–server software structure for an efficient integration of CAD and FEA using a strict separation of geometric and non‐geometric aspects will also be outlined. Copyright © 2001 John Wiley & Sons, Ltd.
FETI‐DP: a dual–primal unified FETI method—part I: A faster alternative to the two‐level FETI method
Authors: Farhat Charbel , Lesoinne Michel , LeTallec Patrick , Pierson Kendall , Rixen Daniel 
Published: August 2002

AbstractThe FETI method and its two‐level extension (FETI‐2) are two numerically scalable domain decomposition methods with Lagrange multipliers for the iterative solution of second‐order solid mechanics and fourth‐order beam, plate and shell structural problems, respectively.The FETI‐2 method distinguishes itself from the basic or one‐level FETI method by a second set of Lagrange multipliers that are introduced at the subdomain cross‐points to enforce at each iteration the exact continuity of a subset of the displacement field at these specific locations. In this paper, we present a dual–primal formulation of the FETI‐2 concept that eliminates the need for that second set of Lagrange multipliers, and unifies all previously developed one‐level and two‐level FETI algorithms into a single dual–primal FETI‐DP method. We show that this new FETI‐DP method is numerically scalable for both second‐order and fourth‐order problems. We also show that it is more robust and more computationally efficient than existing FETI solvers, particularly when the number of subdomains and/or processors is very large. Copyright © 2001 John Wiley & Sons, Ltd.
Automatic generation of transitional meshes
Authors: Field David A. 
Published: August 2002

AbstractAdvances in commercial computer‐aided design software have made finite element analysis with three‐dimensional solid finite elements routinely available. Since these analyses usually confine themselves to those geometrical objects for which particular CAD systems can produce finite element meshes, expanding the capability of analyses becomes an issue of expanding the capability of generating meshes. This paper presents a method for stitching together two three‐dimensional meshes with diverse elements that can include tetrahedral, pentahedral and hexahedral solid finite elements. The stitching produces a mesh that coincides with the edges which already exist on the portion of boundaries that will be joined. Moreover, the transitional mesh does not introduce new edges on these boundaries. Since the boundaries of the regions to be stitched together can have a mixture of triangles and quadrilaterals, tetrahedral and pyramidal elements provide the transitional elements required to honor these constraints. On these boundaries a pyramidal element shares its base face with the quadrilateral faces of hexahedra and pentahedra. Tetrahedral elements share a face with the triangles on the boundary. Tetrahedra populate the remaining interior of the transitional region. Copyright © 2001 John Wiley & Sons, Ltd.
Fast direct solvers for Poisson equation on 2D polar and spherical geometries
Authors: Lai Ming‐Chih , Wang Wei‐Cheng 
Published: August 2002

AbstractA simple and efficient class of FFT‐based fast direct solvers for Poisson equation on 2D polar and spherical geometries is presented. These solvers rely on the truncated Fourier series expansion, where the differential equations of the Fourier coefficients are solved by the second‐ and fourth‐order finite difference discretizations. Using a grid by shifting half mesh away from the origin/poles, and incorporating with the symmetry constraint of Fourier coefficients, the coordinate singularities can be easily handled without pole condition. By manipulating the radial mesh width, three different boundary conditions for polar geometry including Dirichlet, Neumann, and Robin conditions can be treated equally well. The new method only needs O(MN log2 N) arithmetic operations for M × N grid points. © 2002 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 18: 56–68, 2002
Hemodialysis patient beliefs by stage of fluid adherence
Authors: Welch Janet L. 
Published: August 2002

AbstractFluid limitations are difficult for hemodialysis patients to follow, and factors related to fluid adherence are not well known. The primary purpose of this study, which was guided by the health belief model and the transtheoretical model for behavior change, was to determine whether differences exist in perceived benefits, barriers, susceptibility, seriousness, or self‐efficacy among individuals in different stages of fluid adherence. In a cross‐sectional descriptive design, 148 persons (mean age=53.9 years; 52% male) were interviewed using a structured format. Hemodialysis patients in the action/maintenance stage perceived significantly more benefits to fluid adherence than persons in the precontemplation stage. Persons who were in the action/maintenance stage perceived they were significantly more susceptible to pulmonary edema than persons in the contemplation stage. Stage‐appropriate interventions may be needed to target specific beliefsabout fluid adherence. © 2001 John Wiley & Sons, Inc. Res Nurs Health 24: 105–112, 2001
Archaeozoological evidence for pastoral systems and herd mobility: the remains from Sos Höyük and Büyüktepe Höyük
Authors: Howell‐Meurs Sarah 
Published: August 2002

AbstractCharacterization of pastoral economics in the archaeological record is recognized as being particularly difficult. While architectural evidence may provide ambiguous indicators of nomadism, animal remains afford greater clarity concerning assessment of herd and thus economic mobility. To highlight archaeozoological applications towards the analysis of herd movement as it may relate to the analysis and definition of economic systems, the mobility of the pastoral systems practised at Sos Höyük and Büyüktepe Höyük during the Early Bronze and Iron Age periods was investigated in terms of various facets of archaeozoological evidence. Sedentary occupation of these sites was suggested by the faunal remains on the basis of evidence, including use of seasonally available resources, relative abundance and representation of the main domesticates and dental data. These results suggest that analysis based upon multiple lines of archaeozoological evidence provides the most fruitful means of investigating pastoral mobility. Copyright © 2001 John Wiley & Sons, Ltd.
Two decapitations from Roman Towcester
Authors: Anderson T. 
Published: August 2002

AbstractTwo young adult males from a Roman cemetery at Towcester show unambiguous evidence of decapitation In one, the skull had been placed over the lower legs, and in the other, the skull was in its correct anatomical position. The significance of this variation and the reasons for decapitation are discussed. Copyright © 2001 John Wiley & Sons, Ltd.