761 research outputs found

    Light Quark Physics with Dynamical Wilson Fermions

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    We present results for spectroscopy, quark masses and decay constants obtained from SESAM's and TkL's large statistics simulations of QCD with two dynamical Wilson fermions.Comment: 3 pages; to appear in the proceedings of Lat.'9

    Light Quark Masses with Dynamical Wilson Fermions

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    We determine the masses of the light and the strange quarks in the MSˉ\bar{MS}-scheme using our high-statistics lattice simulation of QCD with dynamical Wilson fermions. For the light quark mass we find mMSˉlight(2GeV)=2.7(2)MeVm^{light}_{\bar{MS}}(2 GeV) = 2.7(2) MeV, which is lower than in quenched simulations. For the strange quark, in a sea of two dynamical light quarks, we obtain mMSˉstrange(2GeV)=140(20)MeVm^{strange}_{\bar{MS}}(2 GeV) = 140(20) MeV.Comment: 10 pages (latex file, uses epsf-style

    Critical Dynamics of the Hybrid Monte Carlo Algorithm

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    We investigate the critical dynamics of the Hybrid Monte Carlo algorithm approaching the chiral limit of standard Wilson fermions. Our observations are based on time series of lengths O(5000) for a variety of observables. The lattice sizes are 16^3 x 32 and 24^3 x 40. We work at beta=5.6, and kappa=0.156, 0.157, 0.1575, 0.158, with 0.83 > m_pi/m_rho > 0.55. We find surprisingly small integrated autocorrelation times for local and extended observables. The dynamical critical exponent zz of the exponential autocorrelation time is compatible with 2. We estimate the total computational effort to scale between V^2 and V^2.25 towards the chiral limit.Comment: 3 pages, Latex with espcrc2.sty and postscript figures, Talk given at Lattice 9

    Stretched Exponential Relaxation in the Biased Random Voter Model

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    We study the relaxation properties of the voter model with i.i.d. random bias. We prove under mild condions that the disorder-averaged relaxation of this biased random voter model is faster than a stretched exponential with exponent d/(d+α)d/(d+\alpha), where 0<α≀20<\alpha\le 2 depends on the transition rates of the non-biased voter model. Under an additional assumption, we show that the above upper bound is optimal. The main ingredient of our proof is a result of Donsker and Varadhan (1979).Comment: 14 pages, AMS-LaTe

    High incidence of central nervous system involvement in patients with metastatic or locally advanced breast cancer treated with epirubicin and docetaxel

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    Summary Background: Clinically overt central nervous system (CNS) involvement occurs in 10%-15% of patients with advanced breast cancer. Patients and methods: The International Breast Cancer Study Group (IBCSG) conducted a dose-finding phase I trial of epirubicin (E) and docetaxel (D) as first-line therapy in advanced breast cancer patients. The study was expanded into a phase II at the recommended doses of E 90 mg/m2and D 75 mg/m2every three weeks. From July 1996 to May 1998, a total of 92 patients (median age 50 years) entered the two studies. Results: Twenty-eight out of ninety-two patients treated with the combination of E and D (30%) developed CNS metastases (95% confidence limits, 26%-35%), which were cerebral in twenty-five patients, leptomeningeal in two, and both in one. Of these 28 patients, 19 (68%) had an objective response. Median time for the development of CNS metastases from the start of chemotherapy was 15 months (range 5-42), if excluding the 6 patients presenting CNS progression within 3 months from start of treatment. It is notable that 11 patients (39%) had progression in the CNS only. Median survival from appearance of brain metastases in the whole group was only three months (range 1-22). C-erbB-2 overexpression was found in 14 out of 16 patients (87%) in whom the assay was performed (3+ in 10, 2+ in 1 and 1+ in 3 cases). Conclusions: As anthracycline- and taxane-containing regimens are increasingly used both in the metastatic and in the adjuvant setting, a careful monitoring of any neurological symptom is advisable. Our preliminary observation on the possible increase of incidence of CNS involvement in patients with advanced breast cancer receiving this effective drug combination requires further evaluatio

    SESAM and TXL Results for Wilson Action--A Status Report

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    Results from two studies of full QCD with two flavours of dynamical Wilson fermions are presented. At beta=5.6, the region 0.83 > m_pi/m_rho > 0.56 at m_pia > 0.23 L^{-1} is explored. The SESAM collaboration has generated ensembles of about 200 statistically independent configurations on a 16^3 x 32-lattice at three different kappa-values and is entering the final phase of data analysis. The TXL simulation on a 24^3 x 40-lattice at two kappa-values has reached half statistics and data analysis has started recently, hence most results presented here are preliminary. The focus of this report is fourfold: we demonstrate that algorithmic improvements like fast Krylov solvers and parallel preconditioning recently introduced can be put into practise in full QCD simulations, we present encouraging observations as to the critical dynamics of the Hybrid Monte Carlo algorithm in the approach to the chiral limit, we mention signal improvements of noisy estimator techniques for disconnected diagrams to the pi-N sigma term, and we report on SESAM's results for light hadron spectrum, light quark masses, and heavy quarkonia.Comment: 24 pages, tex + postscript figures, to appear in Proceedings of Int. Workshop "Lattice QCD on Parallel Computers", University of Tsukuba, Japa

    Gene sequence variations of the platelet P2Y12 receptor are associated with coronary artery disease

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    <p>Abstract</p> <p>Background</p> <p>The platelet P2Y<sub>12 </sub>receptor plays a key role in platelet activation. The H2 haplotype of the P2Y<sub>12 </sub>receptor gene (<it>P2RY12</it>) has been found to be associated with maximal aggregation response to adenosine diphosphate (ADP) and with increased risk for peripheral arterial disease. No data are available on its association with coronary artery disease (CAD).</p> <p>Methods </p> <p>The H2 haplotype of the <it>P2RY12 </it>was determined in 1378 unrelated patients of both sexes selected according to the presence of significant coronary artery disease (CAD group) or having normal coronary angiogram at cardiac catheterization (CAD-free group). Significant coronary artery disease was angiographically determined, and was defined as a greater than 50% visually estimated luminal diameter stenosis in at least one major epicardial coronary artery.</p> <p>Results</p> <p>In the studied population 71.9% had CAD (n = 991) and 28.1% had normal coronary angiogram (n = 387). H2 haplotype carriers were more frequent in the CAD group (p = 0.03, OR = 1.36, 95%CI = 1.02–1.82). The H2 haplotype was significantly associated with CAD in non-smokers (p = 0.007, OR = 1.83 95%CI = 1.17–2.87), but not in smokers. The association remained significant after adjustment for other covariates (age, triglycerides, HDL, hypertension, diabetes) by multivariate logistic regression (p = 0.004, OR = 2.32 95%CI = 1.30–4.15).</p> <p>Conclusion</p> <p>Gene sequence variations of the P2Y<sub>12 </sub>receptor gene are associated with the presence of significant CAD, particularly in non-smoking individuals.</p

    Reconstruction of the gravitational wave signal h(t)h(t) during the Virgo science runs and independent validation with a photon calibrator

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    The Virgo detector is a kilometer-scale interferometer for gravitational wave detection located near Pisa (Italy). About 13 months of data were accumulated during four science runs (VSR1, VSR2, VSR3 and VSR4) between May 2007 and September 2011, with increasing sensitivity. In this paper, the method used to reconstruct, in the range 10 Hz-10 kHz, the gravitational wave strain time series h(t)h(t) from the detector signals is described. The standard consistency checks of the reconstruction are discussed and used to estimate the systematic uncertainties of the h(t)h(t) signal as a function of frequency. Finally, an independent setup, the photon calibrator, is described and used to validate the reconstructed h(t)h(t) signal and the associated uncertainties. The uncertainties of the h(t)h(t) time series are estimated to be 8% in amplitude. The uncertainty of the phase of h(t)h(t) is 50 mrad at 10 Hz with a frequency dependence following a delay of 8 ÎŒ\mus at high frequency. A bias lower than 4 Όs4\,\mathrm{\mu s} and depending on the sky direction of the GW is also present.Comment: 35 pages, 16 figures. Accepted by CQ

    Measurement of the Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction

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    The Bs0→J/ψKS0B_s^0\to J/\psi K_S^0 branching fraction is measured in a data sample corresponding to 0.41fb−1fb^{-1} of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to the penguin contributions affecting the sin2ÎČ\beta measurement from B0→J/ψKS0B^0\to J/\psi K_S^0 The time-integrated branching fraction is measured to be BF(Bs0→J/ψKS0)=(1.83±0.28)×10−5BF(B_s^0\to J/\psi K_S^0)=(1.83\pm0.28)\times10^{-5}. This is the most precise measurement to date
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