333 research outputs found

    Systematic study of autocorrelation time in pure SU(3) lattice gauge theory

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    Results of our autocorrelation measurement performed on Fujitsu AP1000 are reported. We analyze (i) typical autocorrelation time, (ii) optimal mixing ratio between overrelaxation and pseudo-heatbath and (iii) critical behavior of autocorrelation time around cross-over region with high statistic in wide range of β\beta for pure SU(3) lattice gauge theory on 848^4, 16416^4 and 32432^4 lattices. For the mixing ratio K, small value (3-7) looks optimal in the confined region, and reduces the integrated autocorrelation time by a factor 2-4 compared to the pseudo-heatbath. On the other hand in the deconfined phase, correlation times are short, and overrelaxation does not seem to matter For a fixed value of K(=9 in this paper), the dynamical exponent of overrelaxation is consistent with 2 Autocorrelation measurement of the topological charge on 323×6432^3 \times 64 lattice at β\beta = 6.0 is also briefly mentioned.Comment: 3 pages of A4 format including 7-figure

    Autocorrelation in Updating Pure SU(3) Lattice Gauge Theory by the use of Overrelaxed Algorithms

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    We measure the sweep-to-sweep autocorrelations of blocked loops below and above the deconfinement transition for SU(3) on a 16416^4 lattice using 20000-140000 Monte-Carlo updating sweeps. A divergence of the autocorrelation time toward the critical β\beta is seen at high blocking levels. The peak is near β\beta = 6.33 where we observe 440 ±\pm 210 for the autocorrelation time of 1×11\times 1 Wilson loop on 242^4 blocked lattice. The mixing of 7 Brown-Woch overrelaxation steps followed by one pseudo-heat-bath step appears optimal to reduce the autocorrelation time below the critical β\beta. Above the critical β\beta, however, no clear difference between these two algorithms can be seen and the system decorrelates rather fast.Comment: 4 pages of A4 format including 6-figure

    Finite Temperature Gauge Theory on Anisotropic Lattices

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    The finite temperature transition of QCD can be seen as a change in the structure of the hadrons and as a symmetry breaking transition -- a change in the structure of the vacuum. These phenomena are observed differently and carry complementary information. We aim at a correlated analysis involving hadronic correlators and the vacuum structure including field and density correlations, both non-trivial questions.Comment: 3 pages, Talk presented at LATTICE96(finite temperature

    A Coarse-Grained Field Theory for Density Fluctuations and Correlation Functions of Galactic Objects

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    We present a coarse-grained field theory of density fluctuations for a Newtonian self-gravitating many-body system and apply it to a homogeneous Universe with small density fluctuations. The theory treats the clustering of galaxies and clusters in terms of the field of density fluctuations. The Jeans length λ0\lambda_0, a unique physical scale for a gravitating system, appears naturally as the characteristic scale underlying the large scale structure. Under Gaussian approximation the analytic expressions of ξ(r)\xi(r) and P(k)P(k) are obtained. The correlation amplitude is proportional to the galactic mass, and is oscillating over large scales 100\sim 100 h1h^{-1} Mpc and damped to zero. The spectrum amplitude is inversely proportional to the galactic number density.The preliminary results qualitatively explain some pronounced features of large scale structures.Comment: 7 pages, 4 figures. to appear in A&

    Renormalization Group Flow of SU(3) Gauge Theory

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    We calculate numerically the renormalization group (RG) flow of lattice QCD in two-coupling space, (β1×1,β1×2)(\beta_{1\times 1},\beta_{1\times 2}). This is the first explicit calculation of the RG flow of SU(3) gauge theory. From the RG flow,a renormalized trajectory (RT) is revealed. Its behavior is consistent with the strong coupling expansion near the high-temperature fixed point. Actions with (β1×1,β1×2)(\beta_{1\times 1},\beta_{1\times 2}) are studied; the lattice spacing is evaluated by measuring the string tension from the heavy quark potential. Recovery of the rotational symmetry is studied as a function of the ratio β1×2/β1×1\beta_{1\times 2} / \beta_{1\times 1}

    Identification of disease-causing genes using microarray data mining and gene ontology

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    Background: One of the best and most accurate methods for identifying disease-causing genes is monitoring gene expression values in different samples using microarray technology. One of the shortcomings of microarray data is that they provide a small quantity of samples with respect to the number of genes. This problem reduces the classification accuracy of the methods, so gene selection is essential to improve the predictive accuracy and to identify potential marker genes for a disease. Among numerous existing methods for gene selection, support vector machine-based recursive feature elimination (SVMRFE) has become one of the leading methods, but its performance can be reduced because of the small sample size, noisy data and the fact that the method does not remove redundant genes. Methods: We propose a novel framework for gene selection which uses the advantageous features of conventional methods and addresses their weaknesses. In fact, we have combined the Fisher method and SVMRFE to utilize the advantages of a filtering method as well as an embedded method. Furthermore, we have added a redundancy reduction stage to address the weakness of the Fisher method and SVMRFE. In addition to gene expression values, the proposed method uses Gene Ontology which is a reliable source of information on genes. The use of Gene Ontology can compensate, in part, for the limitations of microarrays, such as having a small number of samples and erroneous measurement results. Results: The proposed method has been applied to colon, Diffuse Large B-Cell Lymphoma (DLBCL) and prostate cancer datasets. The empirical results show that our method has improved classification performance in terms of accuracy, sensitivity and specificity. In addition, the study of the molecular function of selected genes strengthened the hypothesis that these genes are involved in the process of cancer growth. Conclusions: The proposed method addresses the weakness of conventional methods by adding a redundancy reduction stage and utilizing Gene Ontology information. It predicts marker genes for colon, DLBCL and prostate cancer with a high accuracy. The predictions made in this study can serve as a list of candidates for subsequent wet-lab verification and might help in the search for a cure for cancers

    Precise Classification of Generalists is Necessary to Establish Evidence in General Medicine [Response to Letter]

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    Risa Hirata,1 Masaki Tago,1 Kiyoshi Shikino,2,3 Takashi Watari,4 Hiromizu Takahashi,5 Yosuke Sasaki,6 Taro Shimizu7 1Department of General Medicine, Saga University Hospital, Saga, Japan; 2Department of General Medicine, Chiba University Hospital, Chiba, Japan; 3Department of Community-Oriented Medical Education, Chiba University Graduate School of Medicine, Chiba, Japan; 4Integrated Clinical Education Center, Kyoto University Hospital, Kyoto, Japan; 5Department of General Medicine, Faculty of Medicine, Juntendo University, Tokyo, Japan; 6Department of General Medicine and Emergency Care, Toho University School of Medicine, Tokyo, Japan; 7Department of Diagnostic and Generalist Medicine, Dokkyo Medical University, Tochigi, JapanCorrespondence: Masaki Tago, Department of General Medicine, Saga University Hospital, 5-1-1 Nabeshima, Saga, 849-8501, Japan, Tel +81 952 34 3238, Fax +81 952 34 2029, Email [email protected]

    Short-term interaction between silent and devastating earthquakes in Mexico

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    大地震とスロースリップの相互作用を解明 --メキシコにおける3つの大地震の連鎖的発生のメカニズム--. 京都大学プレスリリース. 2021-04-12.Either the triggering of large earthquakes on a fault hosting aseismic slip or the triggering of slow slip events (SSE) by passing seismic waves involve seismological questions with important hazard implications. Just a few observations plausibly suggest that such interactions actually happen in nature. In this study we show that three recent devastating earthquakes in Mexico are likely related to SSEs, describing a cascade of events interacting with each other on a regional scale via quasi-static and/or dynamic perturbations across the states of Guerrero and Oaxaca. Such interaction seems to be conditioned by the transient memory of Earth materials subject to the “traumatic” stress produced by seismic waves of the great 2017 (Mw8.2) Tehuantepec earthquake, which strongly disturbed the SSE cycles over a 650 km long segment of the subduction plate interface. Our results imply that seismic hazard in large populated areas is a short-term evolving function of seismotectonic processes that are often observable
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