6,971 research outputs found

    Note on Bessaga-Klee classification

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    We collect several variants of the proof of the third case of the Bessaga-Klee relative classification of closed convex bodies in topological vector spaces. We were motivated by the fact that we have not found anywhere in the literature a complete correct proof. In particular, we point out an error in the proof given in the book of C.~Bessaga and A.~Pe\l czy\'nski (1975). We further provide a simplified version of T.~Dobrowolski's proof of the smooth classification of smooth convex bodies in Banach spaces which works simultaneously in the topological case.Comment: 14 pages; we made few corrections, added one reference and precised the abstrac

    Rich families and elementary submodels

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    We compare two methods of proving separable reduction theorems in functional analysis -- the method of rich families and the method of elementary submodels. We show that any result proved using rich families holds also when formulated with elementary submodels and the converse is true in spaces with fundamental minimal system an in spaces of density ℵ1\aleph_1. We do not know whether the converse is true in general. We apply our results to show that a projectional skeleton may be without loss of generality indexed by ranges of its projections

    Describing dynamical fluctuations and genuine correlations by Weibull regularity

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    The Weibull parametrization of the multiplicity distribution is used to describe the multidimensional local fluctuations and genuine multiparticle correlations measured by OPAL in the large statistics e+e−→Z0→hadronse^{+}e^{-} \to Z^{0} \to hadrons sample. The data are found to be well reproduced by the Weibull model up to higher orders. The Weibull predictions are compared to the predictions by the two other models, namely by the negative binomial and modified negative binomial distributions which mostly failed to fit the data. The Weibull regularity, which is found to reproduce the multiplicity distributions along with the genuine correlations, looks to be the optimal model to describe the multiparticle production process.Comment: 10 pages, 2 figure

    Hydrodynamic Interactions in Protein Folding

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    We incorporate hydrodynamic interactions (HI) in a coarse-grained and structure-based model of proteins by employing the Rotne-Prager hydrodynamic tensor. We study several small proteins and demonstrate that HI facilitate folding. We also study HIV-1 protease and show that HI make the flap closing dynamics faster. The HI are found to affect time correlation functions in the vicinity of the native state even though they have no impact on same time characteristics of the structure fluctuations around the native state

    Measurement of π\pi, K, p transverse momentum spectra with ALICE in proton-proton collisions at s=\sqrt{s} = 0.9 and 7 TeV

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    Results of the measurement of the π\pi, K, p transverse momentum (ptp_{\mathrm{t}}) spectra at mid-rapidity in proton-proton collisions at s=7\sqrt{s} = 7 TeV are presented. Particle identification was performed using the energy loss signal in the Inner Tracking System (ITS) and the Time Projection Chamber (TPC), while information from the Time-of-Flight (TOF) detector was used to identify particles at higher transverse momentum. From the spectra at s=7\sqrt{s} = 7 TeV the mean transverse momentum () and particle ratios were extracted and compared to results obtained for collisions at s=0.9\sqrt{s} = 0.9 TeV and lower energies.Comment: Quark Matter 2011 proceeding

    Surface losses and self-pumping effects in a long Josephson junction - a semi-analytical approach

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    The flux-flow dynamics in a long Josephson junction is studied both analytically and numerically. A realistic model of the junction is considered by taking into account a nonuniform current distribution, surface losses and self-pumping effects. An approximate analytical solution of the modified sine-Gordon equation is derived in the form of a unidirectional dense fluxon train accompanied by two oppositely directed plasma waves. Next, some macroscopic time-averaged quantities are calculated making possible to evaluate the current-voltage characteristic of the junction. The results obtained by the present method are compared with direct numerical simulations both for the current-voltage characteristics and for the loss factor modulated spatially due to the self-pumping. The comparison shows very good agreement for typical junction parameters but indicates also some limitations of the method.Comment: 7 pages, 5 figure
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