153 research outputs found

    The heat kernel of the compactified D=11 supermembrane with non-trivial winding

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    We study the quantization of the regularized hamiltonian, HH, of the compactified D=11 supermembrane with non-trivial winding. By showing that HH is a relatively small perturbation of the bosonic hamiltonian, we construct a Dyson series for the heat kernel of HH and prove its convergence in the topology of the von Neumann-Schatten classes so that eHte^{-Ht} is ensured to be of finite trace. The results provided have a natural interpretation in terms of the quantum mechanical model associated to regularizations of compactified supermembranes. In this direction, we discuss the validity of the Feynman path integral description of the heat kernel for D=11 supermembranes and obtain a matrix Feynman-Kac formula.Comment: 19 pages. AMS LaTeX. A whole new section was added and some other minor changes in style where mad

    Decoding the functional relevance of intrinsic brain activity with (TMS-)EEG

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    Physiological Fluid Flow Moderates Fibroblast Responses to TGF-β1.

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    Fibroblasts are the major cellular component of connective tissue and experience mechanical perturbations due to matrix remodelling and interstitial fluid movement. Transforming growth factor β1 (TGF-β1) can promote differentiation of fibroblasts in vitro to a contractile myofibroblastic phenotype characterised by the presence of α-smooth muscle actin (α-SMA) rich stress fibres. To study the role of mechanical stimulation in this process, we examined the response of primary human fibroblasts to physiological levels of fluid movement and its influence on fibroblast differentiation and responses to TGF-β1. We report that in both oral and dermal fibroblasts, physiological levels of fluid flow induced widespread changes in gene expression compared to static cultures, including up-regulation of genes associated with TGFβ signalling and endocytosis. TGF-β1, activin A and markers of myofibroblast differentiation including α-SMA and collagen IA1 were also increased by flow but surprisingly the combination of flow and exogenous TGF-β1 resulted in reduced differentiation. Our findings suggest this may result from enhanced internalisation of caveolin and TGF-β receptor II. These findings suggest that a) low levels of fluid flow induce myofibroblast differentiation and b) fluid flow antagonises the fibroblast response to pro-differentiation signals such as TGF-β1. We propose that this may be a novel mechanism by which mechanical forces buffer responses to chemical signals in vivo, maintaining a context-specific fibroblast phenotype. This article is protected by copyright. All rights reserved

    Examining the glottal stop as a mark of gender-inclusive language German

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    Gefördert im Rahmen des Projekts DEA

    Hoe werkt bestuurskunde?

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    Bestuurskunde studeren en dan… een baan. Hoe gaat dat of liever gezegd hoe werkt bestuurskunde in de praktijk

    Decoding the functional relevance of intrinsic brain activity with (TMS-)EEG

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