12,564 research outputs found

    Extension of Tycho catalog for low-extinction windows in the galactic bulge

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    We present in this work secondary catalogs up to mVal∌13m_{Val} \sim 13 based on the Tycho reference frame (ESA, 1997) for 12 selected low-extinction fields towards the galactic bulge. The observations have been performed with the Askania-Zeiss Meridian Circle equiped with a CCD camera, located at the Abrah\~ao de Moraes Observatory (Valinhos, Brazil) and operated by the Institute of Astronomy and Geophysics, S\~ao Paulo University. The presented catalog, though not complete, has been designed to help in intensive search programmes (e.g. microlensing and variable searches) and therefore the selected standards have a high astrometric and photometric (VV band, approximately) quality. The mean precisions obtained were 0.0018s0.0018^{s} in α\alpha, 0.013'' in ÎŽ\delta, 0.030 for the standard deviation in magnitude and 0.0042 for the magnitude when weighted with the error bars in each night (in the mean, 42 stars for the catalog of each window). Tables B.1 to B.12 are also available in eletronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html.Comment: 16 pages, 6 figures, A&A Latex style. Published in A&A

    Stellar variability in low-extinction regions towards the Galactic Bulge

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    Intensive monitoring of low-extinction windows towards the galactic bulge has provided in the last years valuable information for studies about the dynamics, kinematics and formation history of this part of the galaxy, mainly by characterizing the bulge stellar populations (Paczy\'nski, 1996). Since 1997, we have been conducting an intensive photometric-astrometric survey of the galactic bulge, with the monitoring of about 120000 stars in 12 windows uniformly distributed in galactic latitude and longitude (Blanco & Terndrup, 1989 e Blanco, 1988) never before submitted to this kind of survey. For this purpose, we have used the IAG/USP CCD Meridian Circle of the Abrah\~ao de Moraes Observatory. The main objective of this work is the identification and classification of variable objects. In this work we present the set up and development of the necessary tools for a project like this and the posterior analysis of our data. We briefly describe the construction of a program to organize and detect variables among the observed stars, including real time alerts (for variations greater than 0.3 magnitudes). The preliminary analysis after the processing of 76 nights of observation yielded 479 variable stars, from which 96.7 % of them are new. We discuss the preliminary classification of this variables, based on: a) the observed amplitude of variation; b) the shape of light curve; c) the expected variable classes among our data and d) the calculated periods, whenever possible. Finally, we discuss the future perspectives for the project and for the applications and analysis of the discovered variable stars.Comment: 10 pages, 14 figures. Accepted by A&A

    The justice system is failing victims and survivors of sexual violence

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    Tammi Walker, Alison Foster, Rabiya Majeed-Ariss and Miranda Horvath on a role for psychologists in improving processes and protection around rape cases. The justice system in England and Wales continues to fail survivors of sexual violence. Official figures from the Crown Prosecution Service and Police highlight the ongoing problem of attrition of rape cases from the criminal justice system. Here, we outline the limitations of the endless cycle of reviews in response to the poor treatment of survivors. We argue that solutions which could lead to significant improvements for survivors of sexual violence are possible

    Factorization of Fermion Doubles on the Lattice

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    We address the problem of the fermion species doubling on the Lattice. Our strategy is to factorize the fermion doubles from the action. The mass term of the Dirac-Wilson action is changed. In this case the extra roots which appear in the action of free fermions in the moment representation are independent of the mass and can be factorized from the fermion propagator. However the gauge couplings suffer from the pathological ghost poles which are common to non-local actions. This action can be used to find a solution of the Ginsparg Wilson relation, which is cured from the non-local pathology. Finally we compare this factorized action with solutions of The Ginsparg Wilson relation. We find that the present is equivalent to the Zenkin action, and that is not quite as local as the Neuberger action.Comment: 7 Latex Revtex pages, 4 ps figures. The paper was improoved due to Comments received. It has a new section and several new reference

    A variable neurodegenerative phenotype with polymerase gamma mutation

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    mtDNA replication and repair, causes mitochondrial diseases including autosomal dominant progressive external ophthalmoplegia (PEO),1 childhood hepato-encephalopathy (Alpers– Huttenlocher syndrome), adult-onset spinocerebellar ataxia, and sensory nerve degeneration with dysarthria and ophthalmoparesis (SANDO)

    Overlap Valence on 2+1 Flavor Domain Wall Fermion Configurations with Deflation and Low-mode Substitution

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    The overlap fermion propagator is calculated on 2+1 flavor domain wall fermion gauge configurations on 16^3 x 32, 24^3 x 64 and 32^3 x 64 lattices. With HYP smearing and low eigenmode deflation, it is shown that the inversion of the overlap operator can be expedited by ~ 20 times for the 16^3 x 32 lattice and ~ 80 times for the 32^3 x 64 lattice. Through the study of hyperfine splitting, we found that the O(m^2a^2) error is small and these dynamical fermion lattices can adequately accommodate quark mass up to the charm quark. The low energy constant \Delta_{mix} which characterizes the discretization error of the pion made up of a pair of sea and valence quarks in this mixed action approach is calculated via the scalar correlator with periodic and anti-periodic boundary conditions. It is found to be small which shifts a 300 MeV pion mass by ~ 10 to 19 MeV on these sets of lattices. We have studied the signal-to-noise issue of the noise source for the meson and baryon. It is found that the many-to-all meson and baryon correlators with Z_3 grid source and low eigenmode substitution is efficient in reducing errors for the correlators of both mesons and baryons. With 64-point Z_3 grid source and low-mode substitution, it can reduce the statistical errors of the light quark (m_{\pi} ~ 200 - 300 MeV) meson and nucleon correlators by a factor of ~ 3-4 as compared to the point source. The Z_3 grid source itself can reduce the errors of the charmonium correlators by a factor of ~ 3.Comment: 30 pages, 18 figures, replaced with the version to be published in PR

    Evidence for a Very Large-Scale Fractal Structure in the Universe from Cobe Measurements

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    In this work, we analyse the temperature fluctuations of the cosmic microwave background radiation observed by COBE and show that the distribution can be fitted by a fractal distribution with a fractal dimension D=1.43±0.07 D= 1.43 \pm 0.07 . This value is in close agreement with the fractal dimension obtained by Coleman and Pietronero (1992) and Luo and Schramm (1992) from galaxy-galaxy and cluster-cluster correlations up to ∌100h−1Mpc \sim 100 h^{-1} Mpc. The fact that the observed temperature fluctuations correspond to scales much larger than 100h−1Mpc 100 h^{-1} Mpc and are signatures of the primordial density fluctuations at the recombination layer suggests that the structure of the matter at the early universe was already fractal and thus non-homogeneous on those scales. This result may have important consequences for the theoretical framework that describes the universe.Comment: 11 pages, postscript file, 2 figures available upon request. To appear in ApJ Letter

    Systematic study of the decay rates of antiprotonic helium states

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    A systematic study of the decay rates of antiprotonic helium (\pbhef and \pbhet) at CERN AD (Antiproton Decelerator) has been made by a laser spectroscopic method. The decay rates of some of its short-lived states, namely those for which the Auger rates ÎłA\gamma_{\mathrm{A}} are much larger than their radiative decay rates (Îłrad∌1\gamma_{\mathrm{rad}} \sim 1 ÎŒ\mus−1^{-1}), were determined from the time distributions of the antiproton annihilation signals induced by laser beams, and the widths of the atomic resonance lines. The magnitude of the decay rates, especially their relation with the transition multipolarity, is discussed and compared with theoretical calculations.Comment: 6 pages, 5 figures, and 1 tabl

    Color-flavor locked strange matter

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    We analyze how the CFL states in dense matter work in the direction of enhancing the parameter space for absolutely stable phases (strange matter). We find that the "CFL strange matter" phase can be the true ground state of hadronic matter for a much wider range of the parameters of the model (the gap of the QCD Cooper pairs Δ\Delta, the strange quark mass msm_s and the Bag Constant BB) than the state without any pairing, and derive a full equation of state and an accurate analytic approximation to the lowest order in Δ\Delta and msm_{s} which may be directly used for applications. The effects of pairing on the equation of state are found to be small (as previously expected) but not negligible and may be relevant for astrophysics.Comment: 5 pages, 2 figure

    Optimizing ribavirin dose in HIV/hepatitis C (HCV) co-infected individuals treated for HCV

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    Hepatitis C (HCV) and HIV share common transmission pathways and the acquisition of both viruses are relatively common. Concurrent treatment for HCV with highly active anti-retroviral therapy (HAART) should be considered in HIV co-infected individuals to decrease the progression of liver damage. Adverse effects and less satisfactory treatment outcomes are often concerns when treating co-infected individuals. Although, direct acting antivirals (DAAs) may increase SVR, they may not be possible because of drug-drug interactions. he objective of this study is to investigate the difference in response rates of HCV treatment in HIV co-infected inmates with varying doses of ribavirin. Retrospective medical chart reviews of 52 HCV/HIV co-infected inmates who underwent HCV therapy between 2003 and 2010. All received standard doses of pegylated interferon alpha 2a or 2b and 800–1600 mg of ribavirin depending on weight. The recommended dosage for genotypes 2 and 3 is 800 mg/day. For other genotypes, if weight is<75 kg, the recommended ribavirin dose is 1000 mg/day or 1200 mg/day if>75 kg. Efficacy was defined as attaining sustained virological response (SVR) six months post treatment. Univariate analyses was performed using SPSS-18; Chi-square test with p-value<0.05 was defined significant. 52 co-infected (3 females & 49 males) were identified. Mean age was 40±7 years. Caucasians accounted for 84.6%; First Nations for 13.5% and Asians 1.9%. 36 were concurrently on HAART. The genotype distribution was: geno 1, 66.0%; geno 2, 7.5%; geno 3, 26.4%. SVR by ribavirin dosage ratio (actual dosage/recommended dosage):=1.0; 41.2% (14/34),>1.0; 58.8% (20/34). Doses greater than 1.5 times were associated with higher adverse events and lower SVR. Suboptimal doses of weight-based ribavirin may be contributing to a lower treatment response in HCV/HIV co-infectants. In our experience, the optimal dose of ribavirin is between 1 and 1.2 times the current recommended dose. We recommend that ribavirin dose be individualized in co-infected in order to enhance the likelihood of achieving SVR. Dual therapy is more practical in many of our population because of chaotic lifestyle. Therefore optimizing the ribavirin dose should be initially undertaken
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