719 research outputs found

    The control of a nuclear reactor using helium- 3 gas control elements

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    Control system for water moderated reactor using helium-3 ga

    The bicompletion of the Hausdorff quasi-uniformity

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    We study conditions under which the Hausdorff quasi-uniformity UH{\mathcal U}_H of a quasi-uniform space (X,U)(X,{\mathcal U}) on the set P0(X){\mathcal P}_0(X) of the nonempty subsets of XX is bicomplete. Indeed we present an explicit method to construct the bicompletion of the T0T_0-quotient of the Hausdorff quasi-uniformity of a quasi-uniform space. It is used to find a characterization of those quasi-uniform T0T_0-spaces (X,U)(X,{\mathcal U}) for which the Hausdorff quasi-uniformity U~H\widetilde{{\mathcal U}}_H of their bicompletion (X~,U~)(\widetilde{X},{\widetilde{\mathcal U}}) on P0(X~){\mathcal P}_0(\widetilde{X}) is bicomplete

    Deformation theory of objects in homotopy and derived categories I: general theory

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    This is the first paper in a series. We develop a general deformation theory of objects in homotopy and derived categories of DG categories. Namely, for a DG module EE over a DG category we define four deformation functors \Def ^{\h}(E), \coDef ^{\h}(E), \Def (E), \coDef (E). The first two functors describe the deformations (and co-deformations) of EE in the homotopy category, and the last two - in the derived category. We study their properties and relations. These functors are defined on the category of artinian (not necessarily commutative) DG algebras.Comment: Alexander Efimov is a new co-author of this paper. Besides some minor changes, Proposition 7.1 and Theorem 8.1 were correcte

    Self-Organized Criticality model for Brain Plasticity

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    Networks of living neurons exhibit an avalanche mode of activity, experimentally found in organotypic cultures. Here we present a model based on self-organized criticality and taking into account brain plasticity, which is able to reproduce the spectrum of electroencephalograms (EEG). The model consists in an electrical network with threshold firing and activity-dependent synapse strenghts. The system exhibits an avalanche activity power law distributed. The analysis of the power spectra of the electrical signal reproduces very robustly the power law behaviour with the exponent 0.8, experimentally measured in EEG spectra. The same value of the exponent is found on small-world lattices and for leaky neurons, indicating that universality holds for a wide class of brain models.Comment: 4 pages, 3 figure

    Liquid-liquid equilibrium for monodisperse spherical particles

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    A system of identical particles interacting through an isotropic potential that allows for two preferred interparticle distances is numerically studied. When the parameters of the interaction potential are adequately chosen, the system exhibits coexistence between two different liquid phases (in addition to the usual liquid-gas coexistence). It is shown that this coexistence can occur at equilibrium, namely, in the region where the liquid is thermodynamically stable.Comment: 6 pages, 8 figures. Published versio

    Spatiotemporal complexity of the universe at subhorizon scales

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    This is a short note on the spatiotemporal complexity of the dynamical state(s) of the universe at subhorizon scales (up to 300 Mpc). There are reasons, based mainly on infrared radiative divergences, to believe that one can encounter a flicker noise in the time domain, while in the space domain, the scaling laws are reflected in the (multi)fractal distribution of galaxies and their clusters. There exist recent suggestions on a unifying treatment of these two aspects within the concept of spatiotemporal complexity of dynamical systems driven out of equilibrium. Spatiotemporal complexity of the subhorizon dynamical state(s) of the universe is a conceptually nice idea and may lead to progress in our understanding of the material structures at large scalesComment: references update

    Scaling-violation phenomena and fractality in the human posture control systems

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    By analyzing the movements of quiet standing persons by means of wavelet statistics, we observe multiple scaling regions in the underlying body dynamics. The use of the wavelet-variance function opens the possibility to relate scaling violations to different modes of posture control. We show that scaling behavior becomes close to perfect, when correctional movements are dominated by the vestibular system.Comment: 12 pages, 4 figures, to appear in Phys. Rev.

    Massive orbital metastasis of hepatocellular carcinoma

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    Federal University of São Paulo Multidisciplinary Oncology Group/Department of PathologyUNIFESP, Multidisciplinary Oncology Group/Department of PathologySciEL

    A novel HLA-B18 restricted CD8+ T cell epitope is efficiently cross-presented by dendritic cells from soluble tumor antigen

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    NY-ESO-1 has been a major target of many immunotherapy trials because it is expressed by various cancers and is highly immunogenic. In this study, we have identified a novel HLA-B*1801-restricted CD8<sup>+</sup>T cell epitope, NY-ESO-1<sub>88–96</sub> (LEFYLAMPF) and compared its direct- and cross-presentation to that of the reported NY-ESO-1<sub>157–165</sub> epitope restricted to HLA-A*0201. Although both epitopes were readily cross-presented by DCs exposed to various forms of full-length NY-ESO-1 antigen, remarkably NY-ESO-1<sub>88–96</sub> is much more efficiently cross-presented from the soluble form, than NY-ESO-1<sub>157–165</sub>. On the other hand, NY-ESO-1<sub>157–165</sub> is efficiently presented by NY-ESO-1-expressing tumor cells and its presentation was not enhanced by IFN-γ treatment, which induced immunoproteasome as demonstrated by Western blots and functionally a decreased presentation of Melan A<sub>26–35</sub>; whereas NY-ESO-1<sub>88–96</sub> was very inefficiently presented by the same tumor cell lines, except for one that expressed high level of immunoproteasome. It was only presented when the tumor cells were first IFN-γ treated, followed by infection with recombinant vaccinia virus encoding NY-ESO-1, which dramatically increased NY-ESO-1 expression. These data indicate that the presentation of NY-ESO-1<sub>88–96</sub> is immunoproteasome dependent. Furthermore, a survey was conducted on multiple samples collected from HLA-B18+ melanoma patients. Surprisingly, all the detectable responses to NY-ESO-1<sub>88–96</sub> from patients, including those who received NY-ESO-1 ISCOMATRIX™ vaccine were induced spontaneously. Taken together, these results imply that some epitopes can be inefficiently presented by tumor cells although the corresponding CD8<sup>+</sup>T cell responses are efficiently primed in vivo by DCs cross-presenting these epitopes. The potential implications for cancer vaccine strategies are further discussed
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