2,718 research outputs found

    Dual Superconductors and SU(2) Yang-Mills

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    We propose that the SU(2) Yang-Mills theory can be interpreted as a two-band dual superconductor with an interband Josephson coupling. We discuss various consequences of this interpretation including electric flux quantization, confinement of vortices with fractional flux, and the possibility that a closed vortex loop exhibits exotic exchange statistics

    On correlation between protein secondary structure, backbone bond angles, and side-chain orientations

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    We investigate the fine structure of the sp3 hybridized covalent bond geometry that governs the tetrahedral architecture around the central Cα_\alpha carbon of a protein backbone, and for this we develop new visualization techniques to analyze high resolution X-ray structures in Protein Data Bank. We observe that there is a correlation between the deformations of the ideal tetrahedral symmetry and the local secondary structure of the protein. We propose a universal coarse grained energy function to describe the ensuing side-chain geometry in terms of the Cβ_\beta carbon orientations. The energy function can model the side-chain geometry with a sub-atomic precision. As an example we construct the Cα_\alpha-Cβ_\beta structure of HP35 chicken villin headpiece. We obtain a configuration that deviates less than 0.4 \.A in root-mean-square distance from the experimental X-ray structure

    Elastic Energy and Phase Structure in a Continuous Spin Ising Chain with Applications to the Protein Folding Problem

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    We present a numerical Monte Carlo analysis of a continuos spin Ising chain that can describe the statistical proterties of folded proteins. We find that depending on the value of the Metropolis temperature, the model displays the three known nontrivial phases of polymers: At low temperatures the model is in a collapsed phase, at medium temperatures it is in a random walk phase, and at high temperatures it enters the self-avoiding random walk phase. By investigating the temperature dependence of the specific energy we confirm that the transition between the collapsed phase and the random walk phase is a phase transition, while the random walk phase and self-avoiding random walk phase are separated from each other by a cross-over transition. We also compare the predictions of the model to a phenomenological elastic energy formula, proposed by Huang and Lei to describe folded proteins.Comment: 12 pages, 23 figures, RevTeX 4.

    Abelian and Non-Abelian Induced Parity Breaking Terms at Finite Temperature

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    We compute the exact canonically induced parity breaking part of the effective action for 2+1 massive fermions in particular Abelian and non Abelian gauge field backgrounds. The method of computation resorts to the chiral anomaly of the dimensionally reduced theory.Comment: 13 pages, RevTeX, no figure

    What is the best treatment for pertussis?

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    A short-term course of erythromycin, azithromycin, or clarithromycin is as effective as a long-term (2-week) erythromycin therapy in eradicating Bordetella pertussis from the nasopharynx (strength of recommendation [SOR]: A; based on one meta-analysis of randomized controlled trials [RCTs]). Evidence is insufficient to determine the benefit of antibiotic prophylaxis for pertussis contacts. However, due to high mortality and morbidity, prophylaxis is recommended for families who have an infant less than 6 months old (SOR: C; based on expert opinion)

    Expressive Harms, Bizarre Districts, and Voting Rights: Evaluating Election-District Appearances After \u3cem\u3eShaw v. Reno\u3c/em\u3e

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    This article attempts to define the constitutional principles that characterize Shaw and to suggest how those principles might be applied in a consistent, meaningful way. Part I, in which we argue that Shaw must be understood to rest on a distinctive conception of the kinds of harms against which the Constitution protects, is the theoretical heart of the article. We call these expressive harms, as opposed to more familiar, material harms. In Part II, we briefly survey the history of previous, largely unsuccessful, efforts in other legal contexts to give principled content to these kinds of harms in redistricting. Parts III and IV then provide an alternative for evaluating district appearance by developing a quantitative approach for measuring district shapes that is most consistent with the theory of Shaw. These Parts are the empirical and social-scientific heart of the article. We apply our quantitative approach to congressional districts throughout the country, enabling meaningful comparisons between the congressional district at issue in Shaw and other districts. We also compare the shapes of congressional districts historically to test whether the district in Shaw is a distinctly recent phenomenon. In doing so, we identify the kind of districts most constitutionally vulnerable after Shaw. In Part V, we describe the further questions that lower courts must answer in deciding whether particular vulnerable districts ultimately fail the constitutional standard outlined in Shaw
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