257,047 research outputs found

    Differential equation for spectral flows of hermitean Wilson-Dirac operator

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    Establishing an exact relation for the derivative we show that the eigenvalue flows of the hermitean Wilson-Dirac operator obey a differential equation. We obtain a complete overview of the characteristic features of its solutions. The underlying mathematical aspects are fully clarified.Comment: 7 pages, remarks on applications added, to appear in Phys. Lett.

    Multicultural Considerations for Building Learning Communities

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    Educational policies call for inclusion and attention to cultural differences in our schools. Administrators, classroom educators, counselors, and other support staff attempt to attend to students through a cooperative effort of connecting with the community beyond the school building, as well as the families represented within it. As Christians, there is a higher calling to truly embrace those often underserved in our learning communities. This paper will address multicultural issues important for United States and United Kingdom school system staff to be mindful of when focusing on students and their families

    The harmonious chromatic number of almost all trees

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    Dynamic mechanical response of polymer networks

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    The dynamic-mechanical response of flexible polymer networks is studied in the framework of tube model, in the limit of small affine deformations, using the approach based on Rayleighian dissipation function. The dynamic complex modulus G* is calculated from the analysis of a network strand relaxation to the new equilibrium conformation around the distorted primitive path. Chain equilibration is achieved via a sliding motion of polymer segments along the tube, eliminating the inhomogeneity of the polymer density caused by the deformation. The characteristic relaxation time of this motion separates the low-frequency limit of the complex modulus from the high-frequency one, where the main role is played by chain entanglements, analogous to the rubber plateau in melts. The dependence of storage and loss moduli, G' and G'', on crosslink and entanglement densities gives an interpolation between polymer melts and crosslinked networks. We discuss the experimental implications of the rather short relaxation time and the slow square-root variation of the moduli and the loss factor tan at higher frequencies.Comment: Journal of Chemical Physics (Oct-2000); Lates, 4 EPS figures include

    Multivariate Measures of Concordance for Copulas and their Marginals

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    Building upon earlier work in which axioms were formulated for multivariate measures of concordance, we examine properties of such measures. In particular, we examine the relations between the measure of concordance of an nn-copula and the measures of concordance of the copula's marginals

    Topology and chiral symmetry in finite temperature QCD

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    We investigate the realization of chiral symmetry in the vicinity of the deconfinement transition in quenched QCD using overlap fermions. Via the index theorem obeyed by the overlap fermions, we gain insight into the behavior of topology at finite temperature. We find small eigenvalues, clearly separated from the bulk of the eigenvalues, and study the properties of their distribution. We compare the distribution with a model of a dilute gas of instantons and anti-instantons and find good agreement.Comment: 3 pages with 3 ps figures; to appear in the proceedings of Lattice '99, Pisa, Italy, June 29 -- July 3, 1999. LATTICE99(topology

    Directing and requesting: two interactive uses of the mental state terms want and need

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    This article is focused on the uses of the terms want and need to build directives and requests in family interaction. The study is located within the theoretical framework of discursive psychology, using the methods of conversation analysis. Within social cognitive research, mental state terms are analyzed as references to inner mental experiences. In contrast, this article analyzes the selection of want and need as sequential phenomena. The use of I want to deliver directives increases the likelihood of compliance when one cannot monitor or control whether a projected action will be carried out. Requests built using I need are recurrently delivered following a request from an interlocutor and delay the granting of the request while maintaining alignment. Thus rather than simply expressing an internal mental experience, the verbs want and need have specific practical uses in their normative sequential environments

    Probing the QCD vacuum with overlap fermions

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    We use low lying eigenvectors of the overlap-Dirac operator as a probe of the QCD vacuum. If instantons play a significant role one would expect the low lying eigenmodes of the overlap-Dirac operator to consist mainly of the mixed ``would be zero modes''. Then, the eigenmodes should exhibit local chirality. Studying a recently introduced local chirality parameter, we find evidence supporting this picture.Comment: LaTeX, 5 pages, 5 postscript figures. Talk given by U.M. Heller at the Workshop on Lattice Hadron Physics ``LHP2001'', July 9 -- 18, 2001, Cairns, Australi

    Inter-dependence of the volume and stress ensembles and equipartition in statistical mechanics of granular systems

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    We discuss the statistical mechanics of granular matter and derive several significant results. First, we show that, contrary to common belief, the volume and stress ensembles are inter-dependent, necessitating the use of both. We use the combined ensemble to calculate explicitly expectation values of structural and stress-related quantities for two-dimensional systems. We thence demonstrate that structural properties may depend on the angoricity tensor and that stress-based quantities may depend on the compactivity. This calls into question previous statistical mechanical analyses of static granular systems and related derivations of expectation values. Second, we establish the existence of an intriguing equipartition principle - the total volume is shared equally amongst both structural and stress-related degrees of freedom. Third, we derive an expression for the compactivity that makes it possible to quantify it from macroscopic measurements.Comment: 5 pages, including 2 figures, To appear in Phys. Rev. Let

    Literacy practices: using the literacies for learning in further education framework to analyse literacy practices on a post-compulsory education and training teacher education programme

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    The Literacies for learning in further education framework describes nine aspects of a literacy practice that elaborate the basic questions of what?, why?, who?, and how? that are needed to understand and describe literacy practices. The framework was used to analyse two literacy practices encountered on initial teacher education courses in the post-compulsory education and training (PCET) phase of the Teacher Education Department in order to understand those literacy practices and improve them. The framework was found to be a useful tool in articulating competing and contradictory purposes in literacy practices in order to clarify them particularly in the context of the complex partnership and stakeholder relationships within teacher education. It was also useful as a planning tool to support collaborative work between the PCET phase of the Teacher Education Department and faculty-based and central support services in supporting the academic literacy of trainees. The use of the framework by other University departments should be considered in supporting academic literacy
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