46,398 research outputs found

    Quasiquarks in two stream system

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    We study the collective quark excitations in an extremely anisotropic system of two interpenetrating streams of the quark-gluon plasma. In contrast to the gluon modes, all quark ones appear to be stable in such a system. Even more, the quark modes in the two-stream system are very similar to those in the isotropic plasma.Comment: 4 pages, 2 figures, minor corrections, to appear in Phys. Rev.

    Chromodynamic Fluctuations in Quark-Gluon Plasma

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    Fluctuations of chromodynamic fields in the collisionless quark-gluon plasma are found as a solution of the initial value linearized problem. The plasma initial state is on average colorless, stationary and homogeneous. When the state is stable, the initial fluctuations decay exponentially and in the long-time limit a stationary spectrum of fluctuations is established. For the equilibrium plasma it reproduces the spectrum which is provided by the fluctuation-dissipation relation. Fluctuations in the unstable plasma, where the memory of initial fluctuations is not lost, are also discussed.Comment: 19 pages, numerous but minor corrections, to appear in Phys. Rev.

    Topological characteristics of oil and gas reservoirs and their applications

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    We demonstrate applications of topological characteristics of oil and gas reservoirs considered as three-dimensional bodies to geological modeling.Comment: 12 page

    Hard exclusive wide-angle processes

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    In this talk the handbag approach to hard exclusive wide-angle processes is reviewed and applications, as for instance two-photon annihilations into pairs of mesons, are discussed.Comment: 11 pages, 8 figures, using latex2e, invited talk presented at Meson 2012, Cracow 201

    Exclusive production of π+π\pi^+\pi^- and π0π0\pi^0\pi^0 pairs in photon-photon and in ultrarelativistic heavy ion collisions

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    The γγππ\gamma\gamma\to\pi\pi reactions are discussed. To describe those processes, we include dipion continuum, resonances, high-energy pion-pion rescatterings, ρ\rho meson exchange and pQCD Brodsky-Lepage mechanisms. The cross section for the production of pion pairs in photon-photon collisions in peripheral heavy ion collisions is calculated with the help of Equivalent Photon Approximaption (EPA) in the impact parameter space. We show predictions at sNN=3.5\sqrt{s_{NN}}=3.5 TeV which could be measured e.g. by the ALICE collaboration at the LHC.Comment: 4 pages, 7 figures, 1 table, talk by M. Klusek-Gawenda at MESON2012, 31 May - 5 June 2012, Krakow, Polan

    Dispersion relations and speeds of sound in special sectors for the integrable chain with alternating spins

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    Based on our previous analysis \cite{doerfel3} of the anisotropic integrable chain consisting of spins s=1/2s=1/2 and s=1s=1 we compare the dispersion relations for the sectors with infinite Fermi zones. Further we calculate the speeds of sound for regions close to sector borders, where the Fermi radii either vanish or diverge, and compare the results.Comment: 11 pages, LaTeX2e, uses iopart.cls,graphicx.sty and psfrag.sty, 2 figure

    p_T-fluctuations in high-energy p-p and A-A collisions

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    The event-by-event p_T-fluctuations in proton-proton and central Pb-Pb collisions, which have been experimentally studied by means of the so-called Phi-measure, are analyzed. The contribution due to the correlation which couples the average p_T to the event multiplicity is computed. The correlation appears to be far too weak to explain the preliminary experimental value of Phi (p_T) in p-p interactions. The significance of the result is discussed.Comment: 5 pages, 2 figures, minor improvement

    Performance analysis of a parallel, multi-node pipeline for DNA sequencing

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    Post-sequencing DNA analysis typically consists of read mapping followed by variant calling and is very time-consuming, even on a multi-core machine. Recently, we proposed Halvade, a parallel, multi-node implementation of a DNA sequencing pipeline according to the GATK Best Practices recommendations. The MapReduce programming model is used to distribute the workload among different workers. In this paper, we study the impact of different hardware configurations on the performance of Halvade. Benchmarks indicate that especially the lack of good multithreading capabilities in the existing tools (BWA, SAMtools, Picard, GATK) cause suboptimal scaling behavior. We demonstrate that it is possible to circumvent this bottleneck by using multiprocessing on high-memory machines rather than using multithreading. Using a 15-node cluster with 360 CPU cores in total, this results in a runtime of 1 h 31 min. Compared to a single-threaded runtime of similar to 12 days, this corresponds to an overall parallel efficiency of 53%
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