4,595 research outputs found

    Spectra of Quarkonia at Finite Temperature

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    Finite-temperature spectra of heavy quarkonia are calculated by combining potential model and thermofield dynamics formalisms. The mass spectra of the heavy quarkonia with various quark contents are calculated. It is found that binding mass of the quarkonium decreases as temperature increases.Comment: 12 pages, 1 figure. To appear Mod.Phys.Lett.

    Oxidative Stress Induced Lipid Peroxidation And DNA Adduct Formation In The Pathogenesis Of Multiple Myeloma And Lymphoma

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    Objective: To access the oxidative stress status by quantification of byproducts generated during lipid peroxidation and DNA breakdown products generated during DNA damage in the blood serum of multiple myeloma and lymphoma patients.Material & Methods: Case control study comprised of 40 patients of multiple myeloma and 20 patients of lymphoma along with 20 age and sex-matched healthy subjects as controls. Levels of Malondialdehyde and 8-hydroxy-2-deoxy-Guanosine were measured to study the oxidative stress status in the study subjects.Results: The level of markers of DNA damage and lipid peroxidation were found to be raised significantly in the study subjects in comparison to healthy controls. The results indicate oxidative stress and DNA damage activity increase progressively with the progression of disease.Conclusion: Oxidative stress causes DNA damage and Lipid peroxidation which results in the formation of DNA adducts leading to mutations thereby indicate the role of oxidative stress in the pathogenesis of multiple myeloma and lymphoma

    Valuation of scleroderma and psoriatic arthritis health states by the general public

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    <p>Abstract</p> <p>Objective</p> <p>Psoriatic arthritis (PsA) and scleroderma (SSc) are chronic rheumatic disorders with detrimental effects on health-related quality of life. Our objective was to assess health values (utilities) from the general public for health states common to people with PsA and SSc for economic evaluations.</p> <p>Methods</p> <p>Adult subjects from the general population in a Midwestern city (N = 218) completed the SF-12 Health Survey and computer-assisted 0-100 rating scale (RS), time trade-off (TTO, range: 0.0-1.0) and standard gamble (SG, range: 0.0-1.0) utility assessments for several hypothetical PsA and SSc health states.</p> <p>Results</p> <p>Subjects included 135 (62%) females, 143 (66%) Caucasians, and 62 (28%) African-Americans. The mean (SD) scores for the SF-12 Physical Component Summary scale were 52.9 (8.3) and for the SF-12 Mental Component Summary scale were 49.0 (9.1), close to population norms. The mean RS, TTO, and SG scores for PsA health states varied with severity, ranging from 20.2 to 63.7 (14.4-20.3) for the RS 0.29 to 0.78 (0.24-0.31) for the TTO, and 0.48 to 0.82 (0.24-0.34) for the SG. The mean RS, TTO, and SG scores for SSc health states were 25.3-69.7 (15.2-16.3) for the RS, 0.36-0.80 (0.25-0.31) for the TTO, and 0.50-0.81 (0.26-0.32) for the SG, depending on disease severity.</p> <p>Conclusion</p> <p>Health utilities for PsA and SSc health states as assessed from the general public reflect the severity of the diseases. These descriptive findings could have implications regarding comparative effectiveness research for tests and treatments for PsA and SSc.</p

    Amplification of Fluctuations in Unstable Systems with Disorder

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    We study the early-stage kinetics of thermodynamically unstable systems with quenched disorder. We show analytically that the growth of initial fluctuations is amplified by the presence of disorder. This is confirmed by numerical simulations of morphological phase separation (MPS) in thin liquid films and spinodal decomposition (SD) in binary mixtures. We also discuss the experimental implications of our results.Comment: 15 pages, 4 figure

    Time correlations in a confined magnetized free-electron gas

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    The time-dependent pair correlation functions for a degenerate ideal quantum gas of charged particles in a uniform magnetic field are studied on the basis of equilibrium statistics. In particular, the influence of a flat hard wall on the correlations is investigated, both for a perpendicular and a parallel orientation of the wall with respect to the field. The coherent and incoherent parts of the time-dependent structure function in position space are determined from an expansion in terms of the eigenfunctions of the one-particle Hamiltonian. For the bulk of the system, the intermediate scattering function and the dynamical structure factor are derived by taking successive Fourier transforms. In the vicinity of the wall the time-dependent coherent structure function is found to decay faster than in the bulk. For coinciding positions near the wall the form of the structure function turns out to be independent of the orientation of the wall. Numerical results are shown to corroborate these findings.Comment: 25 pages, 14 figures, to be published in Journal of Physics

    Progress on DC-DC Converters for a Silicon Tracker for the sLHC Upgrade

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    There is a need for DC-DC converters which can operate in the extremely harsh environment of the sLHC Si Tracker. The environment requires radiation qualification to a total ionizing radiation dose of 50 Mrad and a displacement damage fluence of 5 x 1014 /cm2 of 1 MeV equivalent neutrons. In addition a static magnetic field of 2 Tesla or greater prevents the use of any magnetic components or materials. In February 2007 an Enpirion EN5360 was qualified for the sLHC radiation dosage but the converter has an input voltage limited to a maximum of 5.5V. From a systems point of view this input voltage was not sufficient for the application. Commercial LDMOS FETs have developed using a 0.25 ÎŒm process which provided a 12 volt input and were still radiation hard. These results are reported here and in previous papers. Plug in power cards with ×10 voltage ratio are being developed for testing the hybrids with ABCN chips. These plug-in cards have air coils but use commercial chips that are not designed to be radiation hard. This development helps in evaluating system noise and performance. GaN FETs are tested for radiation hardness to ionizing radiation and displacement damage and preliminary results are given

    Cosmological Magnetogenesis driven by Radiation Pressure

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    The origin of large scale cosmological magnetic fields remains a mystery, despite the continuous efforts devoted to that problem. We present a new model of magnetic field generation, based on local charge separation provided by an anisotropic and inhomogeneous radiation pressure. In the cosmological context, the processes we explore take place at the epoch of the reionisation of the Universe. Under simple assumptions, we obtain results (i) in terms of the order of magnitude of the field generated at large scales and (ii) in terms of its power spectrum. The amplitudes obtained (B ~ 8.10^(-6) micro-Gauss) are considerably higher than those obtained in usual magnetogenesis models and provide suitable seeds for amplification by adiabatic collapse and/or dynamo during structure formation.Comment: 9 pages, 2 figure

    Factorizations and Physical Representations

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    A Hilbert space in M dimensions is shown explicitly to accommodate representations that reflect the prime numbers decomposition of M. Representations that exhibit the factorization of M into two relatively prime numbers: the kq representation (J. Zak, Phys. Today, {\bf 23} (2), 51 (1970)), and related representations termed q1q2q_{1}q_{2} representations (together with their conjugates) are analysed, as well as a representation that exhibits the complete factorization of M. In this latter representation each quantum number varies in a subspace that is associated with one of the prime numbers that make up M
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