29,957 research outputs found

    The Higgs Boson Mass from Precision Electroweak Data

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    We present a new global fit to precision electroweak data, including new low- and high-energy data and analyzing the radiative corrections arising from the minimal symmetry breaking sectors of the Standard Model (SM) and its supersymmetric extension (MSSM). It is shown that present data favor a Higgs mass of O(M_Z): M_H = 76+152-50 GeV. We confront our analysis with (meta)stability and perturbative bounds on the SM Higgs mass, and the theoretical upper bound on the MSSM Higgs mass. Present data do not discriminate significantly between the SM and MSSM Higgs mass ranges. We comment in passing on the sensitivity of the Higgs mass determination to the values of alpha(M_Z) and alpha_s(M_Z).Comment: 10 pages, latex, 8 figures as uu-encoded postscript fil

    Advanced general aviation comparative engine/airframe integration study

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    The NASA Advanced Aviation Comparative Engine/Airframe Integration Study was initiated to help determine which of four promising concepts for new general aviation engines for the 1990's should be considered for further research funding. The engine concepts included rotary, diesel, spark ignition, and turboprop powerplants; a conventional state-of-the-art piston engine was used as a baseline for the comparison. Computer simulations of the performance of single and twin engine pressurized aircraft designs were used to determine how the various characteristics of each engine interacted in the design process. Comparisons were made of how each engine performed relative to the others when integrated into an airframe and required to fly a transportation mission

    Rights-based reasoning in discussions about lesbian and gay issues: implications for moral educators

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    Despite a paucity of psychological research exploring the interface between lesbian and gay issues and human rights, a human rights framework has been widely adopted in debates to gain equality for lesbians and gay men. Given this prominence within political discourse of human rights as a framework for the promotion of positive social change for lesbians and gay men, the aim of this study was to explore the extent to which rights-based arguments are employed when talking about lesbian and gay issues in a social context. An analysis of six focus group discussions with students showed that when lesbian and gay issues are discussed, rights-based reasoning is employed intermittently, and in relation to certain issues more so than others. The implications of these findings for moral education aimed at promoting positive social change for lesbians and gay men are discussed.</p

    The exterior degree of a pair of finite groups

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    The exterior degree of a pair of finite groups (G,N)(G,N), which is a generalization of the exterior degree of finite groups, is the probability for two elements (g,n)(g,n) in (G,N)(G,N) such that gn=1g\wedge n=1. In the present paper, we state some relations between this concept and the relative commutatively degree, capability and the Schur multiplier of a pair of groups.Comment: To appear in Mediterr. J. Mat

    Neutrino Oscillations Induced by Gravitational Recoil Effects

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    Quantum gravitational fluctuations of the space-time background, described by virtual D branes, may induce neutrino oscillations if a tiny violation of the Lorentz invariance (or a violation of the equivalence principle) is imposed. In this framework, the oscillation length of massless neutrinos turns out to be proportional to M/E^2, where E is the neutrino energy and M is the mass scale characterizing the topological fluctuations in the vacuum. Such a functional dependence on the energy is the same obtained in the framework of loop quantum gravity.Comment: 5 pages, LaTex fil

    DiBELLA: Distributed long read to long read alignment

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    We present a parallel algorithm and scalable implementation for genome analysis, specifically the problem of finding overlaps and alignments for data from "third generation" long read sequencers [29]. While long sequences of DNA offer enormous advantages for biological analysis and insight, current long read sequencing instruments have high error rates and therefore require different approaches to analysis than their short read counterparts. Our work focuses on an efficient distributed-memory parallelization of an accurate single-node algorithm for overlapping and aligning long reads. We achieve scalability of this irregular algorithm by addressing the competing issues of increasing parallelism, minimizing communication, constraining the memory footprint, and ensuring good load balance. The resulting application, diBELLA, is the first distributed memory overlapper and aligner specifically designed for long reads and parallel scalability. We describe and present analyses for high level design trade-offs and conduct an extensive empirical analysis that compares performance characteristics across state-of-the-art HPC systems as well as a commercial cloud architectures, highlighting the advantages of state-of-the-art network technologies

    Exact non-equilibrium solutions of the Einstein-Boltzmann equations. II

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    We find exact solutions of the Einstein-Boltzmann equations with relaxational collision term in FRW and Bianchi I spacetimes. The kinematic and thermodynamic properties of the solutions are investigated. We give an exact expression for the bulk viscous pressure of an FRW distribution that relaxes towards collision-dominated equilibrium. If the relaxation is toward collision-free equilibrium, the bulk viscosity vanishes - but there is still entropy production. The Bianchi I solutions have zero heat flux and bulk viscosity, but nonzero shear viscosity. The solutions are used to construct a realisation of the Weyl Curvature Hypothesis.Comment: 16 pages LaTex, CQG documentstyle (ioplppt

    Geodesic Deviation Equation in Bianchi Cosmologies

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    We present the Geodesic Deviation Equation (GDE) for the Friedmann-Robertson-Walker(FRW) universe and we compare it with the equation for Bianchi type I model. We justify consider this cosmological model due to the recent importance the Bianchi Models have as alternative models in cosmology. The main property of these models, solutions of Einstein Field Equations (EFE) is that they are homogeneous as the FRW model but they are not isotropic. We can see this because they have a non-null Weyl tensor in the GDE.Comment: Submitted to Journal of Physics: Conference Series (JPCS), ERE200

    Inspecting absorption in the spectra of extra-galactic gamma-ray sources for insight into Lorentz invariance violation

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    We examine what the absorbed spectra of extra-galactic TeV gamma-ray sources, such as blazars, would look like in the presence of Lorentz invariance violation (LIV). Pair-production with the extra-galactic background light modifies the observed spectra of such sources, and we show that a violation of Lorentz invariance would generically have a dramatic effect on this absorption feature. Inspecting this effect, an experimental task likely practical in the near future, can provide unique insight on the possibility of LIV.Comment: Published in Phys. Rev.
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