7,844 research outputs found

    On the Symmetric Space Sigma-Model Kinematics

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    The solvable Lie algebra parametrization of the symmetric spaces is discussed. Based on the solvable Lie algebra gauge two equivalent formulations of the symmetric space sigma model are studied. Their correspondence is established by inspecting the normalization conditions and deriving the field transformation laws.Comment: 17 page

    ΔπN\Delta\pi N coupling constant in light cone QCD sum rules

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    We employ the light cone QCD sum rules to calculate ΔπN\Delta\pi N coupling constant by studying the two point correlation function between the vacuum and the pion state. Our result is consistent with the traditional QCD sum rules calculations and it is in agreement with the experimental value.Comment: 8 pages, latex, 2 figure

    Symmetric space sigma-model dynamics: Current formalism

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    After explicitly constructing the symmetric space sigma model lagrangian in terms of the coset scalars of the solvable Lie algebra gauge in the current formalism we derive the field equations of the theory.Comment: 10 page

    g_phi-pion-gamma coupling constant in light cone QCD sum rules

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    The coupling constant of g_phi-pion-gamma decay is calculated using light cone QCD sum rules. A comparison of our result with the ones existing in the literature is presented.Comment: 9 pages, 2 figure

    Mechanics of soil erosion from overland flow generated by simulated rainfall

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    September 1973.Bibliography: pages 53-54

    Study of Eclipsing Binary and Multiple Systems in OB Associations II. The Cygnus OB Region: V443 Cyg, V456 Cyg and V2107 Cyg

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    Three presumably young eclipsing binary systems in the direction of the Cygnus OB1, OB3 and OB9 associations are studied. Component spectra are reconstructed and their orbits are determined using light curves and spectra disentangling techniques. V443 Cyg and V456 Cyg have circular orbits, while the light curve of V2107\,Cyg imposes a slightly eccentric orbit (e=0.045±0.03)e=0.045\pm0.03). V443 Cyg harbours F-type stars, and not young early-A stars as previously suggested in the literature based on photometry solely. It appears to be situated in the foreground (distance 0.6±0.20.6\pm0.2 kpc) of the young stellar populations in Cygnus. V456 Cyg, at a distance of 0.50±0.030.50\pm0.03 kpc consists of a slightly metal-weak A--type and an early--F star. The age of both systems, on or very near to the main sequence, remains uncertain by an order of magnitude. V2107 Cyg is a more massive system (8.9±28.9\pm2 and 4.5±1.2M4.5\pm1.2 M_\odot) at 1.5±0.51.5\pm0.5 kpc and, also kinematically, a strong candidate-member of Cyg OB1. The more massive component is slightly evolved and appears to undergo non-radial βCep\beta Cep-type pulsations. The Doppler signal of the secondary is barely detectable. A more extensive study is important to fix masses more precisely, and an asteroseismological study would then become appropriate. Nevertheless, the position of the primary in the HR-diagram confines the age already reasonably well to 20±520\pm5 Myr, indicating for Cyg OB1 a similar extent of star formation history as established for Cyg OB2.Comment: 27 pages, including 9 figures and 6 tables, accepted for publication in Astronomical Journa

    Subintimal Double-Barrel Restenting of an Occluded Primary Stented Superficial Femoral Artery

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    In-stent re-stenosis is a frequent complication of endovascular stents, especially in the superficial femoral artery (SFA). Endovascular re-intervention of in- or peri-stent occlusive disease consists of recanilization through the occluded stent. In our case report, we describe the endovascular treatment of a previously placed stent in the SFA. We unintentionally passed the affected stent subintimally, in a double barrel fashion next to the first stent. The procedure was without any complications and with a successfull angiographic result. At one year follow-up the patient still has no complaints and the stent is still patent
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