Distribution by Scientific Domains
Distribution within Engineering

Kinds of Convergence

  • asymptotic convergence
  • evolutionary convergence
  • exponential convergence
  • fast convergence
  • faster convergence
  • flux convergence
  • functional convergence
  • global convergence
  • global exponential convergence
  • good convergence
  • moisture convergence
  • morphological convergence
  • optimal convergence
  • policy convergence
  • possible convergence
  • price convergence
  • productivity convergence
  • quadratic convergence
  • rapid convergence
  • recent convergence
  • regional convergence
  • second-order convergence
  • slow convergence
  • uniform convergence
  • weak convergence

  • Terms modified by Convergence

  • convergence analysis
  • convergence angle
  • convergence behavior
  • convergence behaviour
  • convergence characteristic
  • convergence condition
  • convergence criterioN
  • convergence criterion
  • convergence factor
  • convergence hypothesis
  • convergence line
  • convergence performance
  • convergence problem
  • convergence process
  • convergence proof
  • convergence property
  • convergence rate
  • convergence result
  • convergence speed
  • convergence studies
  • convergence study
  • convergence test
  • convergence theorem
  • convergence theory
  • convergence time
  • convergence zone

  • Selected Abstracts


    EVOLUTION, Issue 5 2007
    Stephen Wroe
    Phenotypic similarities between distantly related marsupials and placentals are commonly presented as examples of convergence and support for the role of adaptive evolution in shaping morphological and ecological diversity. Here we compare skull shape in a wide range of carnivoran placentals (Carnivora) and nonherbivorous marsupials using a three-dimensional (3-D) geometric morphometric approach. Morphological and ecological diversity among extant carnivorans is considerably greater than is evident in the marsupial order Dasyuromorphia with which they have most commonly been compared. To examine convergence across a wider, but broadly comparable range of feeding ecologies, a dataset inclusive of nondasyuromorphian marsupials and extinct taxa representing morphotypes no longer present was assembled. We found support for the adaptive paradigm, with correlations between morphology, feeding behavior, and bite force, although skull shape better predicted feeding ecology in the phylogenetically diverse marsupial sample than in carnivorans. However, we also show that remarkably consistent but differing constraints have influenced the evolution of cranial shape in both groups. These differences between carnivorans and marsupials, which correlate with brain size and bite force, are maintained across the full gamut of morphologies and feeding categories, from small insectivores and omnivores to large meat-specialists. [source]


    EVOLUTION, Issue 2 2005
    Luke J. Harmon
    Abstract Convergent evolution has played an important role in the development of the ecological niche concept. We investigated patterns of convergent and divergent evolution of Caribbean Anolis lizards. These lizards diversified independently on each of the islands of the Greater Antilles, producing the same set of habitat specialists on each island. Using a phylogenetic comparative framework, we examined patterns of morphological convergence in five functionally distinct sets of morphological characters: body size, body shape, head shape, lamella number, and sexual size dimorphism. We find evidence for convergence among members of the habitat specialist types for each of these five datasets. Furthermore, the patterns of convergence differ among at least four of the five datasets; habitat specialists that are similar for one set of characters are often greatly different for another. This suggests that the habitat specialist niches into which these anoles have evolved are multidimensional, involving several distinct and independent aspects of morphology. [source]


    EVOLUTION, Issue 6 2000
    Kevin E. Omland
    Abstract. Several empirical studies suggest that sexually selected characters, including bird plumage, may evolve rapidly and show high levels of convergence and other forms of homoplasy. However, the processes that might generate such convergence have not been explored theoretically. Furthermore, no studies have rigorously addressed this issue using a robust phylogeny and a large number of signal characters. We scored the appearance of 44 adult male plumage characters that varied across New World orioles (Icterus). We mapped the plumage characters onto a molecular phylogeny based on two mitochondrial genes. Reconstructing the evolution of these characters revealed evidence of convergence or reversal in 42 of the 44 plumage characters. No plumage character states are restricted to any groups of species higher than superspecies in the oriole phylogeny. The high frequency of convergence and reversal is reflected in the low overall retention index (RI = 0.66) and the low overall consistency index (CI = 0.28). We found similar results when we mapped plumage changes onto a total evidence tree. Our findings reveal that plumage patterns and colors are highly labile between species of orioles, but highly conserved within the oriole genus. Furthermore, there are at least two overall plumage types that have convergently evolved repeatedly in the three oriole clades. This overall convergence leads to significant conflict between the molecular and plumage data. It is not clear what evolutionary processes lead to this homoplasy in individual characters or convergence in overall pattern. However, evolutionary constraints such as developmental limitations and genetic correlations between characters are likely to play a role. Our results are consistent with the belief that avian plumage and other sexually selected characters may evolve rapidly and may exhibit high homoplasy. The overall convergence in oriole plumage patterns is an interesting evolutionary phenomenon, but it cautions against heavy reliance on plumage characters for constructing phylogenies. [source]


    MODERN THEOLOGY, Issue 1 2008
    The intent of this essay is to place the thinking of Martin Heidegger and Pierre Teilhard de Chardin in dialogue with one another in order to thresh out the latent aspects of each thinker's work that are often seen to be problematic. I argue that Teilhard's discussion of unity that differentiates illuminates a positive teleology in Heidegger's notion of Appropriation, while Heidegger's conception of retrieval/repetition discloses the significance of historical reinterpretation in Teilhard's Christology. I therefore reply to accusations that Heidegger's philosophy succumbs to relativism and reduction into Being and that Teilhard neglects history in his treatment of Omega Point. [source]


    MODERN THEOLOGY, Issue 1 2005
    When we grasp Calvin's emphasis on the covenant history in its theological and Christological aspects and the relationship of this emphasis to Calvin's humanistic understanding of history, then we can understand the convergence of the historical and the Christological senses in Calvin's reading of Scripture. This understanding of Calvin's approach questions modernity's narrow historiographical bounds for discerning Scripture's historical sense, opening us to a consideration of a wider array of practices. Brueggemann's historiographical suggestions about the importance of Israel's witness and practice for reading scripture both historically and theologically fall within this broader frame and are congenial to Calvin's work. [source]


    This paper applies a dynamic panel model to explore whether the low-income countries ,catch up' with the rich ones by examining the threshold effects of per capita income on the convergence behavior of growth rates. Empirical evidence from 121 Penn World Table economies and 48 US states indicates that income levels have substantial impacts on the convergence behavior. First, convergence is insignificantly found in the lowest-income regimes, which is interpreted that these poor countries persist at their income levels, which cause possible income barriers-to-growth. That is, the poor countries may not be able to catch up with the rich ones easily, unless an income threshold is overcome. Second, convergence is significantly found beyond the lowest-income regime, implying that the low-income countries catch up with the rich. We conclude that when a certain income threshold is overcome, the poor countries catch up with the rich ones; hence a subsidiary income policy can be helpful. [source]


    David Enoch
    First page of article [source]

    Psychometric properties of the Trauma Assessment for Adults

    Matt J. Gray Ph.D.
    Abstract Background: The Trauma Assessment for Adults (TAA) was developed to facilitate the assessment of exposure to traumatic events that could result in posttraumatic stress disorder (PTSD). The TAA inquires about numerous potentially traumatic events that an individual may have experienced. Although the TAA has been used extensively for clinical and research purposes, its psychometric properties have never been formally evaluated. The objective of the present investigation was to evaluate the psychometric properties of this frequently used measure. Methods: The studies reported here describe the performance of the TAA in two samples,college undergraduates (N=142) and community mental health center clients (N=67). Among undergraduates, 1-week temporal stability was evaluated and, in both samples, item- and scale-level convergence of the TAA with an established trauma exposure measure was assessed. Convergence of the TAA with clinically related constructs was also evaluated. Results: The TAA exhibited adequate temporal stability (r=.80) and satisfactory item-level convergence with existing measures of trauma history among college students. In the clinical sample, the TAA again converged well with an established measure of trauma exposure (r=.65). It was not as strongly predictive, in either sample, of trauma-related distress relative to an alternate trauma exposure measure. Conclusion: Although it performs satisfactorily, the TAA does not appear to be superior to other existing measures of trauma exposure. Depression and Anxiety, 2009. © 2008 Wiley-Liss, Inc. [source]

    Convergence and extension movements affect dynamic notochord-somite interactions essential for zebrafish slow muscle morphogenesis

    Chunyue Yin
    Abstract During vertebrate gastrulation, convergence and extension (C&E) movements shape and position the somites that form the fast and slow muscles. In zebrafish knypek;trilobite non-canonical Wnt mutants, defective C&E movements cause misshapen somites and reduction of slow muscle precursors, the adaxial cells. Here, we demonstrate essential roles of C&E in slow muscle morphogenesis. During segmentation, the adaxial cells change shapes and migrate laterally to form slow muscles at the myotome surface. Using confocal imaging techniques, we show that the adaxial cells undergo three-step shape changes, including dorsoventral elongation, anterior-ward rotation, and anteroposterior elongation. The adaxial cells in knypek;trilobite double mutants maintain prolonged contact with the notochord and fail to rotate anteriorly. Such a defect was suppressed by physical removal of their notochord or by introducing wild-type notochord cells into the mutant. We propose that in the double mutants, impaired C&E movements disrupt notochord development, which impedes the adaxial cell shape changes. Developmental Dynamics 236:2742,2756, 2007. © 2007 Wiley-Liss, Inc. [source]

    Convergence of multisensory inputs in Xenopus tadpole tectum

    Masaki Hiramoto
    Abstract The integration of multisensory information takes place in the optic tectum where visual and auditory/mechanosensory inputs converge and regulate motor outputs. The circuits that integrate multisensory information are poorly understood. In an effort to identify the basic components of a multisensory integrative circuit, we determined the projections of the mechanosensory input from the periphery to the optic tectum and compared their distribution to the retinotectal inputs in Xenopus laevis tadpoles using dye-labeling methods. The peripheral ganglia of the lateral line system project to the ipsilateral hindbrain and the axons representing mechanosensory inputs along the anterior/posterior body axis are mapped along the ventrodorsal axis in the axon tract in the dorsal column of the hindbrain. Hindbrain neurons project axons to the contralateral optic tectum. The neurons from anterior and posterior hindbrain regions project axons to the dorsal and ventral tectum, respectively. While the retinotectal axons project to a superficial lamina in the tectal neuropil, the hindbrain axons project to a deep neuropil layer. Calcium imaging showed that multimodal inputs converge on tectal neurons. The layer-specific projections of the hindbrain and retinal axons suggest a functional segregation of sensory inputs to proximal and distal tectal cell dendrites, respectively. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009 [source]

    Convergence within the EU: Evidence from Interest Rates

    ECONOMIC NOTES, Issue 2 2000
    Teresa Corzo Santamaria
    The economic and political changes which are taking place in Europe affect interest rates. This paper develops a two-factor model for the term structure of interest rates specially designed to apply to EMU countries. In addition to the participant country's short-term interest rate, we include as a second factor a ,European' short-term interest rate. We assume that the ,European' rate follows a mean reverting process. The domestic interest rate also follows a mean reverting process, but its convergence is to a stochastic mean which is identified with the ,European' rate. Closed-form solutions for prices of zero coupon discount bonds and options on these bonds are provided. A special feature of the model is that both the domestic and the European interest rate risks are priced. We also discuss an empirical estimation focusing on the Spanish bond market. The ,European' rate is proxied by the ecu's interest rate. Through a comparison of the performance of our convergence model with a Vasicek model for the Spanish bond market, we show that our model provides a better fit both in-sample and out-of sample and that the difference in performance between the models is greater the longer the maturity of the bonds. (J.E.L.: E43, C510). [source]

    Is There Conceptual Convergence in Entrepreneurship Research?

    A Co-Citation Analysis of Frontiers of Entrepreneurship Research
    Conceptual convergence is often seen as a holy grail in entrepreneurship research. Yet little empirical research has focused specifically on the extent and nature of this convergence. We address this issue by content-analyzing the networks of co-citation emerging from the 20,184 references listed in the 960 full-length articles published in the Frontiers of Entrepreneurship Research series between 1981 and 2004. Our results provide evidence for the varying levels of convergence that have characterized entrepreneurship research over the years, as well as the evolution of the conceptual themes that have attracted scholars' attention in different periods. In addition, we provide evidence that the field relies increasingly on its own literature, something that points toward the unique contribution that it makes to the management sciences. [source]

    Dinuclear Iridium(III) Complexes Linked by a Bis(,-diketonato) Bridging Ligand: Energy Convergence versus Aggregation-Induced Emission

    Chang Hwan Shin
    Abstract Novel iridium(III)/iridium(III) and iridium(III)/platinum(II) dinuclear complexes, [{Ir(ppyFF)2}2(,2 - L)] (4) and [{Ir(ppyFF)2}(,2 - L){Pt(ppy)}] (5) [ppyFF = 2-(2,4-difluorophenyl)pyridine, ppy = 2-phenylpyridine, L = 1,3-bis(3-phenyl-3-oxopropanoyl)benzene], linked by an L bridging ligand were prepared, and their photophysical properties were investigated in solution and in the solid state. The photophysical properties of mononuclear iridium(III) and platinum(II) complexes, [Ir(ppyFF)2(dbm)] (1) and [Pt(ppy)(dbm)] (2) bearing a dibenzoylmethane (dbm) ligand were also compared. Whereas the UV/Vis absorption spectra of 4 and 5 show independent light absorption at each metal-centered moiety, the photoluminescence spectra of 4 and 5 display almost identical features, but very weak emissions in solution at both room temperature and 77 K. The weak emission in solution is found to mainly originate from a 3LX state of the L bridging ligand, which reflects the occurrence of efficient energy convergence from the triplet states of the Pt(ppy) and Ir(ppyFF) moieties to the 3LX state of L. By contrast, intense orange-red emission, that is, aggregation-induced emission, is produced in the solid state of 4 and 5. Inspection of the crystal-packing structures of 5 reveals that strong intermolecular ,,, interactions between the adjacent pyridine rings of ppyFF ligands in the Ir-centered moieties are responsible for the emissive metal-to-ligand,ligand charge-transfer [3M(LL)CT] state of the solid-state dinuclear systems. The electrochemical properties of 4 and 5 further indicate that the first two reductions occur at the dbm moieties of the L bridging ligand linked to each metal center, which is consistent with the fact that the lowest-energy excited state of the L bridging ligand dominates the excited-state properties of 4 and 5 in solution. [source]

    Reciprocal connections between olfactory structures and the cortex of the rostral superior temporal sulcus in the Macaca fascicularis monkey

    A. Mohedano-Moriano
    Abstract Convergence of sensory modalities in the nonhuman primate cerebral cortex is still poorly understood. We present an anatomical tracing study in which polysensory association cortex located at the fundus and upper bank of the rostral superior temporal sulcus presents reciprocal connections with primary olfactory structures. At the same time, projections from this polysensory area reach multiple primary olfactory centres. Retrograde (Fast Blue) and anterograde (biotinylated dextran,amine and 3H-amino acids) tracers were injected into primary olfactory structures and rostral superior temporal sulcus. Retrograde tracers restricted to the anterior olfactory nucleus resulted in labelled neurons in the rostral portion of the upper bank and fundus of superior temporal sulcus. Injections of biotinylated dextran,amine at the fundus and upper bank of the superior temporal sulcus confirmed this projection by labelling axons in the dorsal and lateral portions of the anterior olfactory nucleus, as well as piriform, periamygdaloid and entorhinal cortices. Retrograde tracer injections at the rostral superior temporal sulcus resulted in neuronal labelling in the anterior olfactory nucleus, piriform, periamygdaloid and entorhinal cortices, thus providing confirmation of the reciprocity between primary olfactory structures and the cortex at the rostral superior temporal sulcus. The reciprocal connections between the rostral part of superior temporal sulcus and primary olfactory structures represent a convergence for olfactory and other sensory modalities at the cortex of the rostral temporal lobe. [source]

    Convergence of excitatory and inhibitory inputs onto CCK-containing basket cells in the CA1 area of the rat hippocampus

    Ferenc Mátyás
    Abstract The number and distribution of excitatory and inhibitory inputs affect the integrative properties of neurons. These parameters have been studied recently for several hippocampal neuron populations. Besides parvalbumin- (PV) containing cells that include basket and axo-axonic cells, cholecystokinin (CCK)-containing interneurons also form a basket cell population with several properties distinct from PV cells. Here, at the light microscopic level, we reconstructed the entire dendritic tree of CCK-immunoreactive (IR) basket cells to describe their geometry, the total length and laminar distribution of their dendrites. This was followed by an electron microscopic analysis of serial ultrathin sections immunostained against ,-aminobutyric acid, to estimate the density of excitatory and inhibitory synapses on their somata, axon initial segments and different subclasses of dendrites. The dendritic tree of CCK-IR basket cells has an average length of 6300 µm and penetrates all layers. At the electron microscopic level, CCK basket cells receive dendritic inputs with a density of 80,230 per 100 µm. The ratio of inhibitory inputs is relatively high (35%) and increases towards the soma (83%). The total numbers of excitatory and inhibitory synapses converging onto CCK-IR cells are ,,8200. Comparison of the two, neurochemically distinct basket cells reveals that CCK-containing basket cells receive much less synaptic input than PV cells; however, the relative weight of inhibition is higher on CCK cells. Additional differences in their anatomical and physiological properties predict that CCK basket cells are under a more diverse, elaborate control than PV basket cells, and thus the function of the two populations must be different. [source]

    Rapid Exponential Convergence of Finite Element Estimates of the Effective Properties of Heterogeneous Materials

    A. Gusev
    We develop and validate a general-purpose error estimator for the finite element solutions for the effective properties of heterogeneous materials. We show that the error should decrease exponentially upon increasing order of the polynomial interpolation. We use this finding to demonstrate the practical feasibility of reliable property predictions for a majority of particulate-morphology heterogeneous materials. [source]

    Learning of foraging skills by fish

    FISH AND FISHERIES, Issue 3 2003
    Kevin Warburton
    Abstract This chapter outlines the relationships between a number of key factors that influence learning and memory, and illustrates them by reference to studies on the foraging behaviour of fish. Learning can lead to significant improvements in foraging performance in only a few exposures, and at least some fish species are capable of adjusting their foraging strategy as patterns of patch profitability change. There is also evidence that the memory window for prey varies between fish species, and that this may be a function of environmental predictability. Convergence between behavioural ecology and comparative psychology offers promise in terms of developing more mechanistically realistic foraging models and explaining apparently ,suboptimal' patterns of behaviour. Foraging decisions involve the interplay between several distinct systems of learning and memory, including those that relate to habitat, food patches, prey types, conspecifics and predators. Fish biologists, therefore, face an interesting challenge in developing integrated accounts of fish foraging that explain how cognitive sophistication can help individual animals to deal with the complexity of the ecological context. [source]

    Convergence of fish communities from the littoral zone of reservoirs

    FRESHWATER BIOLOGY, Issue 6 2009
    Summary 1.,Understanding factors that regulate the assembly of communities is a main focus of ecology. Human-engineered habitats, such as reservoirs, may provide insight into these assembly processes because they represent novel habitats that are subjected to colonization by fishes from the surrounding river basin or transported by humans. By contrasting community similarity within and among reservoirs from different drainage basins to nearby stream communities, we can test the relative constraints of reservoir habitats and regional species pools in determining species composition of reservoirs. 2.,We used a large spatial database that included intensive collections from 143 stream and 28 reservoir sites within three major river basins in the Great Plains, U.S.A., to compare patterns of species diversity and community structure between streams and reservoirs and to characterize variation in fish community structure within and among major drainage basins. We expected reservoir fish faunas to reflect the regional species pool, but would be more homogeneous that stream communities because similar species are stocked and thrive in reservoirs (e.g. planktivores and piscivores), and they lack obligate stream organisms that are not shared among regional species pools. 3.,We found that fish communities from reservoirs were a subset of fishes collected from streams and dominant taxa had ecological traits that would be favoured in lentic environments. Although there were regional differences in reservoir fish communities, species richness, patterns of rank abundance and community structure in reservoir communities were more homogonous across three major drainage basins than for stream communities. 4.,The general pattern of convergence of reservoir fish community structure suggests their assembly is constrained by local factors such as habitat and biotic interactions, and facilitated by the introduction of species among basins. Because there is a reciprocal transfer of biota between reservoirs and streams, understanding factors structuring both habitats is necessary to evaluate the long-term dynamics of impounded river networks. [source]

    Convergence in West German Regional Unemployment Rates

    Christian Bayer
    Stochastic convergence; unemployment; structural break; unit root Abstract. Differences in regional unemployment rates are often used to describe regional economic inequality. This paper asks whether changes in regional unemployment differences in West Germany are persistent over time. Understanding the persistency of regional unemployment differences helps us to assess how effective regional policy can be. While univariate tests suggest that changes in regional unemployment differences are persistent in West Germany, more powerful panel tests lend some support to the hypothesis that regional unemployment rates converge. However, these tests reveal a moderate speed of convergence at best. Because there is a structural break following the second oil crisis, we also use tests that allow for such a break. This provides evidence for both convergence and quick adjustment to an equilibrium distribution of regional unemployment rates that is, however, subject to a structural break. [source]

    Convergence in Structure and Productivity in European Manufacturing?

    Klaus Gugler
    Structural convergence; productivity convergence; growth of industries; European integration Abstract. We find fast convergence in productivity for 99 three-digit European industries over the 1985,98 period. Half of any productivity gap is closed on average in about 10,15 years. We explicitly formulate the steady-state assumptions for structural convergence to hold. Convergence in industrial structure is much slower than productivity catch-up with a half-life of around 50 years, a stylized fact which cannot easily be explained by the existing models of trade and growth. [source]

    Cost Convergence between Public and For-Profit Hospitals under Prospective Payment and High Competition in Taiwan

    Sudha Xirasagar
    Objective. To test the hypotheses that: (1) average adjusted costs per discharge are higher in high-competition relative to low-competition markets, and (2) increased competition is associated with cost convergence between public and for-profit (FP) hospitals for case payment diagnoses, but not for cost-plus reimbursed diagnoses. Data Sources. Taiwan's National Health Insurance database; 325,851 inpatient claims for cesarean section, vaginal delivery, prostatectomy, and thyroidectomy (all case payment), and bronchial asthma and cholelithiasis (both cost-based payment). Study Design. Retrospective population-based, cross-sectional study. Data Analysis. Diagnosis-wise regression analyses were done to explore associations between cost per discharge and hospital ownership under high and low competition, adjusted for clinical severity and institutional characteristics. Principal Findings. Adjusted costs per discharge are higher for all diagnoses in high-competition markets. For case payment diagnoses, the magnitudes of adjusted cost differences between public and FP hospitals are lower under high competition relative to low competition. This is not so for the cost-based diagnoses. Conclusions. We find that the empirical evidence supports both our hypotheses. [source]

    Colloidal Networks: Polymorphic Meniscus Convergence for Construction of Quasi-Periodic Assemblies and Networks of Colloidal Nanoparticles (Adv. Mater.

    ADVANCED MATERIALS, Issue 37 2010
    Quasi-periodic colloidal networks can be constructed on the basis of polymorphic meniscus convergence (MC) in an air-cavity-embedded, nanocolloidal system, report Sin-Doo Lee and coworkers on p. 4172. Depending on the flow associated with the air-cavities, the colloidal particles are self-organized into nanowires through binary MC, hexagonal networks with Y-junctions through ternary MC and square networks with X-junctions through quaternary MC, reflecting the flow symmetry according to the air-cavity deformation. [source]

    Polymorphic Meniscus Convergence for Construction of Quasi-Periodic Assemblies and Networks of Colloidal Nanoparticles

    ADVANCED MATERIALS, Issue 37 2010
    Sang-Wook Lee
    Quasi-periodic colloidal networks are constructed on the basis of polymorphic meniscus convergence (MC) in an air-cavity-embedded, nano-colloidal system. Depending on the flow associated with the air-cavities, the colloidal particles are self-organized into nanowires through binary MC, Y-junctions through ternary MC, and X-junctions through quaternary MC. The colloidal networks in either square or hexagonal form reflect the flow symmetry according to the air-cavity deformation. [source]

    Convergence in human resource systems: A comparison of locally owned and MNC subsidiaries in Taiwan

    Shyh-Jer Chen
    This article investigates issues of convergence in human resource systems in Taiwan, with reference to the similarities and differences between locally owned companies and subsidiaries of multinational corporations (MNCs). Traditionally, management in Taiwanese companies has been largely influenced by Confucian values and is quite distinct from approaches common to MNCs. However, globalization has engendered significant competitive pressures, coupled with cultural and institutional change within Taiwan. This article provides a theoretical framework for understanding such changes and provides empirical evidence indicating that Taiwanese companies are acting very much like MNCs with regard to the adoption of flexible, highperformance work systems. © 2005 Wiley Periodicals, Inc. [source]

    European dimensions to collective bargaining: new symmetries within an asymmetric process?

    Paul Marginson
    The impact of economic and monetary union on the structures, processes and agenda of collective bargaining at sector and company levels is explored. Drawing on cross,national evidence from two sectors, considerable differences between sectors within national boundaries are identified, but also some striking parallels within sectors across national boundaries. Convergence and greater diversity are simultaneously evident. [source]

    Convergence between physiological, facial and verbal self-report measures of affective empathy in children

    Xenia Anastassiou-Hadjicharalambous
    Abstract The present study investigated the degree of convergence between three different measures of vicarious affective responsiveness (affective empathy),verbal self-report, facial expression and change in heart rate,in typically developing children (N=29, aged 8,10 years), when presented with an emotionally evocative film. Although convergence between physiological and verbal measures was only at chance levels, convergence between facial and physiological measures, and between facial and verbal measures was statistically significant, but low (,=0.30 and 0.22, respectively, p<0.01). These findings have important implications for the assessment of empathy in children and indicate that generalization of results across methods should be undertaken with caution. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    The modelling of anchors using the material point method

    C. J. Coetzee
    Abstract The ultimate capacity of anchors is determined using the material point method (MPM). MPM is a so-called meshless method capable of modelling large displacements, deformations and contact between different bodies. A short introduction to MPM is given and the derivation of the discrete governing equations. The analysis of a vertically loaded anchor and one loaded at 45° is presented. The load,displacement curves are compared to that obtained from experiments and the effect of soil stiffness and anchor roughness is investigated. The results of the vertically loaded anchor are also compared to an analytical solution. The displacement of the soil surface above the anchor was measured and compared to the numerical predictions. Convergence with mesh refinement is demonstrated and the effect of mesh size and dilatancy angle on the shear band width and orientation is indicated. The results show that MPM can model anchor pull out successfully. No special interface elements are needed to model the anchor,soil interface and the predicted ultimate capacities were within 10% of the measured values. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Performance of Jacobi preconditioning in Krylov subspace solution of finite element equations

    F.-H. Lee
    Abstract This paper examines the performance of the Jacobi preconditioner when used with two Krylov subspace iterative methods. The number of iterations needed for convergence was shown to be different for drained, undrained and consolidation problems, even for similar condition number. The differences were due to differences in the eigenvalue distribution, which cannot be completely described by the condition number alone. For drained problems involving large stiffness ratios between different material zones, ill-conditioning is caused by these large stiffness ratios. Since Jacobi preconditioning operates on degrees-of-freedom, it effectively homogenizes the different spatial sub-domains. The undrained problem, modelled as a nearly incompressible problem, is much more resistant to Jacobi preconditioning, because its ill-conditioning arises from the large stiffness ratios between volumetric and distortional deformational modes, many of which involve the similar spatial domains or sub-domains. The consolidation problem has two sets of degrees-of-freedom, namely displacement and pore pressure. Some of the eigenvalues are displacement dominated whereas others are excess pore pressure dominated. Jacobi preconditioning compresses the displacement-dominated eigenvalues in a similar manner as the drained problem, but pore-pressure-dominated eigenvalues are often over-scaled. Convergence can be accelerated if this over-scaling is recognized and corrected for. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Matched interface and boundary (MIB) method for the vibration analysis of plates

    S. N. Yu
    Abstract This paper proposes a novel approach, the matched interface and boundary (MIB) method, for the vibration analysis of rectangular plates with simply supported, clamped and free edges, and their arbitrary combinations. In previous work, the MIB method was developed for three-dimensional elliptic equations with arbitrarily complex material interfaces and geometric shapes. The present work generalizes the MIB method for eigenvalue problems in structural analysis with complex boundary conditions. The MIB method utilizes both uniform and non-uniform Cartesian grids. Fictitious values are utilized to facilitate the central finite difference schemes throughout the entire computational domain. Boundary conditions are enforced with fictitious values,a common practice used in the previous discrete singular convolution algorithm. An essential idea of the MIB method is to repeatedly use the boundary conditions to achieve arbitrarily high-order accuracy. A new feature in the proposed approach is the implementation of the cross derivatives in the free boundary conditions. The proposed method has a banded matrix. Nine different plates, particularly those with free edges and free corners, are employed to validate the proposed method. The performance of the proposed method is compared with that of other established methods. Convergence and comparison studies indicate that the proposed MIB method works very well for the vibration analysis of plates. In particular, modal bending moments and shear forces predicted by the proposed method vanish at boundaries for free edges. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    The boundary element method for solving the Laplace equation in two-dimensions with oblique derivative boundary conditions

    D. Lesnic
    Abstract In this communication, we extend the Neumann boundary conditions by adding a component containing the tangential derivative, hence producing oblique derivative boundary conditions. A variant of Green's formula is employed to translate the tangential derivative to the fundamental solution in the boundary element method (BEM). The two-dimensional steady-state heat conduction with the imposed oblique boundary condition has been tested in smooth, piecewise smooth and multiply connected domains in which the Laplace equation is the governing equation, producing results at the boundary in excellent agreement with the available analytical solutions. Convergence of the normal and tangential derivatives at the boundary is also achieved. The numerical boundary data are then used to successfully calculate the values of the solution at interior points again. The outlined test cases have been repeated with various boundary element meshes, indicating that the accuracy of the numerical results increases with increasing boundary discretization. Copyright © 2006 John Wiley & Sons, Ltd. [source]