bluuebunny/crossref_metadata_2025_split huggingface dataset:
Frequency/time‐domain modelling of 3D waveguide structures by a BI‐RME approach
Authors: Arcioni P. , Bozzi M. , Bressan M. , Conciauro G. , Perregrini L. 
Published: October 2002

AbstractThis paper presents a full wave method for the determination of the mathematical model of a 3D waveguide structure in the form of the pole expansion in thes‐plane of its generalized admittance matrix. The method is based on a boundary integral‐resonant mode expansion approach. By the introduction of appropriate state‐variables, the method leads to the pole expansion by solving a linear generalized eigenvalue problem, like in the well‐known techniques used up to now in frequency/time domain modelling based on finite difference or finite element methods. With respect to these methods we have the advantage of a significant reduction in both memory allocation and computing time. Two examples show the accuracy of the results and the efficiency of the method. Copyright © 2002 John Wiley & Sons, Ltd.
A systematic approach for extracting lumped circuit parameters of microstrip discontinuities from their S‐parameter characteristics
Authors: Mittra R. , Suntives A. , Hossain M. S. , Ma J. 
Published: October 2002

AbstractThis paper describes a systematic approach for extracting the lumped circuit parameters of microstrip discontinuities from their S‐parameter characteristics—which are assumed to be known—by using a three‐ step procedure. We begin by computing the lumped equivalent circuit parameters, e.g., L, C, R and/or G, with a direct extraction procedure, which relates the S‐parameters to the Z‐ (or Y‐) parameters of the discontinuity. Next, we use these values as initial guesses for an optimization code based on the genetic algorithm, to obtain circuit parameters that are invariant over a specified frequency range. Finally, we develop an artificial neural network model for predicting the values of these circuit elements rapidly as we change the physical and electrical parameters of the discontinuity, for instance the width or height of the etch, and the complex dielectric constant of the substrate. The application of the direct extraction technique is first illustrated by considering a number of representative two‐port microstrip discontinuities, viz., the chamfered bend and gap discontinuities. It is then extended to three‐port structures, for instance, a T‐junction. The validation is given for the case examples investigated by comparing the S‐parameter calculated from the equivalent circuit with those obtained from a full‐wave EM solver. We also use the chamfered bend as a case example to illustrate the application of this three‐step procedure. Copyright © 2002 John Wiley & Sons, Ltd.
Developmental changes in the expression of iron regulatory proteins and iron transport proteins in the perinatal rat brain
Authors: Siddappa Asha Jyothi M. , Rao Raghavendra B. , Wobken Jane D. , Leibold Elizabeth A. , Connor James R. , Georgieff Michael K. 
Published: October 2002

AbstractThe perinatal brain requires a tightly regulated iron transport system. Iron regulatory proteins (IRPs) 1 and 2 are cytosolic proteins that regulate the stability of mRNA for the two major cellular iron transporters, transferrin receptor (TfR) and divalent metal transporter‐1 (DMT‐1). We studied the localization of IRPs, their change in expression during perinatal development, and their relationship to TfR and DMT‐1 in rat brain between postnatal days (PND) 5 and 15. Twelve‐micron frozen coronal sections of fixed brain tissue were obtained from iron‐sufficient Sprague‐Dawley rat pups on PND 5, 10, and 15, and were visualized at 20 to 1,000× light microscopy for diaminobenzidine activity after incubation with specific primary IRP‐1, IRP‐2, DMT‐1, and TfR antibodies and a universal biotinylated secondary and tertiary antibody system. IRP and transport protein expression increased in parallel over time. IRP1, IRP2, and DMT‐1 were partially expressed in the choroid plexus epithelial cells at PND 5 and 10, and fully expressed at PND 15. The cerebral blood vessels and ependymal cells strongly expressed IRP1, IRP2, and DMT‐1 as early as PND 5. Substantive TfR staining was not seen in the choroid plexus or ependyma until PND 15. Glial and neuronal expression of IRP1, IRP2, DMT‐1, and TfR in cortex, hippocampal subareas and striatum increased over time, but showed variability in cell number and intensity of expression based on brain region, cell type, and age. These developmental changes in IRP and transporter expression suggest potentially different time periods of brain structure vulnerability to iron deficiency or iron overload. © 2002 Wiley‐Liss, Inc.
Extracellular proteolysis in brain injury and inflammation: Role for plasminogen activators and matrix metalloproteinases
Authors: Lo Eng H. , Wang Xiaoying , Cuzner M. Louise 
Published: October 2002

AbstractThe role of intracellular proteases (e.g., calpains and caspases) in the pathophysiology of neuronal cell death has been extensively investigated. More recently, accumulating data have suggested that extracellular proteolysis also plays a critical role. The two major systems that modify the extracellular matrix in brain are the plasminogen activator (PA) and matrix metalloproteinase (MMP) axes. This Mini‐Review delineates major pathways of PA and MMP action after stroke, brain trauma, and chronic inflammation. Deleterious effects include the disruption of blood–brain barrier integrity, amplification of inflammatory infiltrates, demyelination, and possibly interruption of cell–cell and cell–matrix interactions that may trigger cell death. In contrast, PA‐MMP actions may contribute to extracellular proteolysis that mediates parenchymal and angiogenic recovery after brain injury. As the mechanisms of deleterious vs. potentially beneficial PA and MMP actions become better defined, it is hoped that new therapeutic targets will emerge for ameliorating the sequelae of brain injury and inflammation. © 2002 Wiley‐Liss, Inc.
The integrin family of cell adhesion molecules has multiple functions within the CNS
Authors: Milner Richard , Campbell Iain L. 
Published: October 2002

AbstractIntegrins comprise a large family of cell adhesion molecules that mediate interactions between the extracellular environment and the cytoplasm. During the last decade, analysis of the expression and function of these molecules has revealed that integrins regulate many aspects of cell behavior including cell death, proliferation, migration, and differentiation. Within the central nervous system (CNS), most of the early studies focused on the role of integrins in mediating adhesive and migratory events in two distinct processes: neural development and CNS inflammation. Interestingly, recent analysis of transgenic mice has provided some surprising results regarding the role of integrins in neural development. Furthermore, a large body of evidence now supports the idea that in addition to these well‐described functions, integrins play multiple roles in the CNS, both during development and in the adult in areas as diverse as synaptogenesis, activation of microglia, and stabilization of the endothelium and blood‐brain barrier. Many excellent reviews have addressed the contribution of integrins in mediating leukocyte extravasation during CNS inflammation. This review will focus on recently emerging evidence of novel and diverse roles of integrins and their ligands in the CNS during development and in the adult, in health and disease. © 2002 Wiley‐Liss, Inc.
Trust as a mediator of the relationship between organizational justice and work outcomes: test of a social exchange model
Authors: Aryee Samuel , Budhwar Pawan S. , Chen Zhen Xiong 
Published: October 2002

AbstractData obtained from full‐time employees of a public sector organization in India were used to test a social exchange model of employee work attitudes and behaviors. LISREL results revealed that whereas the three organizational justice dimensions (distributive, procedural and interactional) were related to trust in organization only interactional justice was related to trust in supervisor. The results further revealed that relative to the hypothesized fully mediated model a partially mediated model better fitted the data. Trust in organization partially mediated the relationship between distributive and procedural justice and the work attitudes of job satisfaction, turnover intentions, and organizational commitment but fully mediated the relationship between interactional justice and these work attitudes. In contrast, trust in supervisor fully mediated the relationship between interactional justice and the work behaviors of task performance and the individually‐ and organizationally‐oriented dimensions of citizenship behavior. Copyright © 2002 John Wiley & Sons, Ltd.
Synoptic climatology of major floods in the Negev Desert, Israel
Authors: Kahana Ron , Ziv Baruch , Enzel Yehouda , Dayan Uri 
Published: October 2002

AbstractThis study examines the extent to which the floods in the Negev Desert, an area that constitutes the southern half of Israel, are not the outcome of purely local weather conditions but are, rather, the result of distinct synoptic‐scale events. This was done through compiling and analysing a hydro‐climatological database of all the major floods in the Negev, and then categorizing them manually into synoptic types that cause the major floods.The type analysis is based on the US National Meteorological Center data sets with 2.5° × 2.5° resolution analysed by GrADS. Data were compiled and studied for 52 floods for the period 1965–94, with peak discharge above the magnitude of 5 year recurrence intervals (RI > 5 years) in at least one drainage basin.Distinct extreme synoptic patterns are indeed associated with 42 of the 52 floods. They were grouped into four synoptic types, two of which were associated with 37 events: (a) an active Red Sea trough, defined as a surface trough extending from East Africa through the Red Sea toward the eastern Mediterranean, accompanied by a pronounced trough at the 500 hPa level over eastern Egypt: (b) a Syrian low, defined as a well‐developed Mediterranean cyclone accompanied by a pronounced upper‐level trough, both located over Syria. Each of the four synoptic types has its own evolution course, and a unique seasonal and spatial distribution of its associated flooded basins.These findings imply that the major floods in the Negev can be considered as signatures of exceptional synoptic‐scale evolutions, and that major floods reflect extreme climatic events. Our results indicate that it is possible to use a set of dynamic and thermodynamic variables for predicting the occurrence and location of major flash floods. Copyright © 2002 Royal Meteorological Society.
Evaluating Antarctic sea ice variability and its teleconnections in global climate models
Authors: Liu Jiping , Martinson Douglas G. , Yuan Xiaojun , Rind David 
Published: October 2002

AbstractThis study evaluates simulated Antarctic sea ice edge (SIE) variability and its teleconnections in three global coupled climate models (GISS, NCAR and GFDL) against the observations. All models do a reasonable job in simulating the seasonal advance and retreat of the Antarctic sea ice fields. The simulated GISS and NCAR SIE distributions are in agreement with observations in summer and autumn, whereas the GFDL model does best in spring and winter. A common problem is the poor simulation of the observed SIE in the Weddell Sea. All models are not particularly good at simulating the observed regionally varying SIE trends. A comparison of dominant empirical orthogonal function modes of surface air temperature (SAT) variability in each model associated with observed modes show that the models generally capture features of the more prominent covarying spatial patterns such as an El Niño–southern oscillation (ENSO)‐like pattern in the tropical Pacific.The simulated teleconnection patterns between detrended Antarctic SIE anomalies and detrended global SAT anomalies in each model are evaluated for comparison with observed teleconnection patterns. All models capture the ENSO‐like phenomenon to some degree. Also, the GISS and NCAR models capture the Antarctic dipole pattern and meridional banding structure through the Pacific. The Antarctic SIE regions showing the strongest extrapolar teleconnections differ among the models and between the models and observations. Almost all models miss the observed polar–extrapolar teleconnections in the central Indian, western extreme of the tropical and southern Pacific, and over the tropical continents. Copyright © 2002 Royal Meteorological Society.
Formation and reorientation of structure in the surge‐type glacier Kongsvegen, Svalbard
Authors: Woodward John , Murray Tavi , McCaig Andrew 
Published: October 2002

AbstractKongsvegen, a surge‐type glacier in Spitsbergen, Svalbard, shares a tide‐water margin with the glacier Kronebreen. The complex has been in retreat since a surge advance of Kongsvegen around 1948. The surface of Kongsvegen displays suites of deformational structures highlighted by debris‐rich folia. These structures are melting out to form a network of sediment ridges in the grounded terminal area. The structures are also visible in a marginal, 1 km long, 5–20 m high cliff‐face at the terminus. Current models for the evolution of deformational structures at Kongsvegen divide the structures into suites based on their orientation and dip, before assigning a mechanism for genesis based on structure geometry. Interpretation of aerial photographs and field mapping of surface structures suggest that many structures were reorientated or advected during the surge. We suggest that many of the deformational structures highlighted by debris‐rich folia represent reorientated, sediment‐filled crevasses. Some evidence of thrusting is apparent but the process is not as ubiquitous as previously suggested. Many deformational structures also appear to have been offset by more recent structures. Mechanisms of structural development must, therefore, be considered within the context of distinct stages of glacier flow dynamics and multiple surge episodes. Furthermore, evidence for thrusting and folding within the glacier systems of Svalbard has been used as the basis for interpreting Quaternary glacial landforms in the UK. The findings of this paper, therefore, have implications for interpretations of the Quaternary record. Copyright © 2002 John Wiley & Sons, Ltd.
Surface‐enhanced Raman scattering of 3‐phenylpropionic acid (hydrocinnamic acid)
Authors: Castro J. L. , López Ramírez M. R. , López Tocón I. , Otero J. C. 
Published: October 2002

AbstractRaman and surface‐enhanced Raman scattering (SERS) spectra of 3‐phenylpropionic acid on silver colloids at several concentrations and pH values were recorded. The analysis of the spectra indicated that 3‐phenylpropionic acid links to the metal through its carboxylate group, keeping the aromatic ring almost perpendicular to the surface. Moreover, the acid undergoes an α, β‐dehydrogenation in some extension in such a way that the recorded SERS is the result of the competitive adsorption of 3‐phenylpropionic and trans‐cinnamic acids. Likewise, the contribution of the charge‐transfer mechanism to the enhancement of the SERS of 3‐phenylpropionic acid was estimated, making evident its important participation in the enhancement of modes 6a, 9a and 8a. Copyright © 2002 John Wiley & Sons, Ltd.
Studies on ferroelectric perovskites and Bi‐layered compounds using micro‐Raman spectroscopy
Authors: Dobal P. S. , Katiyar R. S. 
Published: October 2002

AbstractThis paper provides a review of a systematic micro‐Raman scattering study on various lead‐ and barium‐based ABO3 perovskites (A = Pb, La, Ba, Sr, Ce, Gd, Nd and B = Ti, Zr), Aurivillius‐type Bi‐layered compounds (SrBi2Ta2O9, Bi4Ti3O12) and their solid solutions useful in a broad range of device applications. Various factors that influence the material properties such as particle size, stresses, stoichiometry, compositional homogeneity and their effects on phase transition were investigated. The processing conditions, A‐ and B‐site substitution, size‐dependent Raman spectra and the structure–property correlations are discussed in the bulk, thin film and nano‐crystalline forms of these materials. A film thickness dependence stress study on lead titanate (PT) and lead zirconate titanate (PZT) films indicated that the nature of stress depends strongly on the lattice parameters of the film and substrate. The size effect was found to decrease the ferroelectric transition temperature in lead‐based perovskite materials. Both ionic charge and radii induced changes in the Raman spectra of A‐ and B‐site substituted perovskites and layered compounds were studied. A‐site substitution in strontium bismuth tantalite (SBT) was found to induce a relatively linear variation of transition temperature compared with the B‐site substituted SBT. Raman spectra of layered compounds and their solid solutions exhibited a strong dependence on dopants resulting in structural modifications. Copyright © 2002 John Wiley & Sons, Ltd.
Outsourcing: a core or non‐core strategic management decision?
Authors: Heikkilä Jussi , Cordon Carlos 
Published: October 2002

Abstract
Practicing managers often use the idea of core competence as one of the principal guidelines for making decisions about outsourcing. Managers of large corporations commonly support their outsourcing decisions with the familiar argument that ‘We keep core competences in‐house, and we outsource non‐core activities’.
This paper questions the usefulness of the ‘non‐core competence’ concept for practical decision making. It reviews and discusses a comprehensive list of drivers for outsourcing decisions as well as the potential risks related to outsourcing initiatives.
Instead of taking the simplistic ‘core or non‐core’ approach, the paper suggests a more creative way to evaluate a larger variety of competencies. The business contexts of four successful companies are described and several examples of their outsourcing/insourcing decisions are presented.
Examples show that poor implementation undermines decisions that are based on even the most imaginative definition of competence structures. Successful outsourcing depends on managing the outsourcing relationship well after the decision is made.
Copyright © 2002 John Wiley & Sons, Ltd.
The rumen digestion of dry matter, nitrogen and cell wall constituents of the pods of Leucaena leucocephala and some Acacia species
Authors: Ngwa A T , Nsahlai I V , Bonsi M L K 
Published: October 2002

AbstractThe disappearance of dry matter (DM), nitrogen and cell wall constituents of the pods of Leucaena leucocephaia and some Acacia species incubated in the rumen of Jersey cattle was studied. The chemical compositions of the pods (seeds + husks), seeds and husks were examined separately. Amino acid and lipid analyses were limited to the pods and seeds, while mineral and tannin analyses were done on the pods alone. The seeds had higher crude protein (CP) contents than the pods, with values ranging from 200 to 300 g CP kg−1 DM. The Leucaena pods and seeds had higher (p > 0.001) CP contents than the Acacia pods and seeds. The neutral detergent fibre concentrations in the husks were higher than in the pods and seeds with the pods of A erioloba having the highest and those of A nilotica the lowest values. These values were highly influenced by the seed/husk ratio. A sieberiana and Leucaena had the highest and lowest concentrations of condensed tannins respectively. The pods of A tortilis and A karoo were particularly rich in macro‐ and micro‐minerals, while the others contained sufficient quantities that could contribute substantially to the dietary requirements of small ruminants. The amino acid concentrations differed significantly (p < 0.001) among the pods, with the Leucaena pods having the highest concentrations. The Leucaena pods and seeds also had higher (p < 0.001) lipid contents than the Acacia pods and seeds. Dry matter and nitrogen degradabilities were higher (p < 0.001) for the pods of A nilotica and A sieberiana, while A karoo had the lowest values. The cell wall constituents of the pods of A tortilis and A erioloba were the most and the least susceptible to microbial degradation respectively. The rates of degradation of the fibre fractions as well as the lag times were similar (p > 0.05) among the pods. The results show that these pods can serve as a valuable source of nitrogen and minerals for ruminants fed roughage‐based diets.© 2001 Society of Chemical Industry
The solubility of potato proteins from industrial potato fruit juice as influenced by pH and various additives
Authors: van Koningsveld Gerrit A , Gruppen Harry , de Jongh Harmen H J , Wijngaards Gerrit , van Boekel Martinus A J S , Walstra Pieter , Voragen Alphons G J 
Published: October 2002

AbstractThe effects of pH and various additives on the precipitation and (re)solubility at pH 7 of potato proteins from industrial potato fruit juice (PFJ) were studied. The use of various strong and weak acids did not result in differences in protein precipitation, which on average occurred to a maximum of 60% of total protein at pH 3. Weak acids did, however, result in precipitates with a higher resolubility at pH 7 compared with strong acids. At pH 5, addition of FeCl3 or ZnCl2 increased both precipitation and resolubility compared with the situation without additives. The largest increases in both precipitation and resolubility were achieved using organic solvents at pH 5 as an additive, resulting in a maximum precipitation and maximum resolubility at pH 7 of 91 and 83% of total protein respectively. The results described in this study lead to the hypothesis that precipitation and resolubilisation of potato proteins from PFJ are not determined by their isoelectric pH but by their interactions with low‐molecular‐weight components.© 2001 Society of Chemical Industry
In vitro degradability of three forages: fermentation kinetics and gas production of NDF and neutral detergent‐soluble fraction of forages
Authors: Calabrò Serena , Infascelli Federico , Bovera Fulvia , Moniello Giuseppe , Piccolo Vincenzo 
Published: October 2002

AbstractThe fermentation of the neutral detergent‐soluble (NDS) fraction of three forages (alfalfa hay, Italian ryegrass + oats hay and corn silage) was measured using a curve subtraction technique with in vitro gas production data from the whole forage (WF) and the isolated neutral detergent fibre (NDF). NDF disappearance and volatile fatty acid (VFA) production were determined. There was no significant difference between the VFA patterns from the whole forage and the isolated NDF. There were significant (P < 0.001) linear correlations between the volume of gas and moles of VFA produced and the mass of fibre digested in the NDF samples. Using the monophasic curve model, maximum gas production rates (RM) for the whole forages and the isolated NDF and NDS fractions can be calculated. For all three forages we obtained RM‐NDS > RM‐WF > RM‐NDF. Trends in the rates of gas and VFA production were similar in the whole forages. The NDF showed a high superimposition between substrate degradability and VFA production. Our experiment confirmed the curve subtraction technique as a simple method to obtain information on the size and digestion kinetics of the NDS fraction, which helps in understanding the nutritional significance of this important fraction of the forages studied.© 2001 Society of Chemical Industry