4,387 research outputs found

    Fermion Determinants

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    The current status of bounds on and limits of fermion determinants in two, three and four dimensions in QED and QCD is reviewed. A new lower bound on the two-dimensional QED determinant is derived. An outline of the demonstration of the continuity of this determinant at zero mass when the background magnetic field flux is zero is also given.Comment: 10 page

    Hadron Mass Predictions of the Valence Approximation to Lattice QCD

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    We evaluate the infinite volume, continuum limits of eight hadron mass ratios predicted by lattice QCD with Wilson quarks in the valence (quenched) approximation. Each predicted ratio differs from the corresponding observed value by less than 6\%.Comment: 13 pages of Latex + 2 PostScript files attached, IBM/HET 92-

    Finite element analysis of wrinkling membranes

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    The development of a nonlinear numerical algorithm for the analysis of stresses and displacements in partly wrinkled flat membranes, and its implementation on the SAP VII finite-element code are described. A comparison of numerical results with exact solutions of two benchmark problems reveals excellent agreement, with good convergence of the required iterative procedure. An exact solution of a problem involving axisymmetric deformations of a partly wrinkled shallow curved membrane is also reported

    Finite element analysis of wrinkling membranes

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    The finite element analysis of wrinkling membranes was investigated. The determination of stresses and deformations within large partly wrinkled membrane surfaces is a problem of significant technical interest in such areas as conceptual design and analysis of ultra lightweight spacecraft structures. A closed-form solution to an axisymmetric problem involving partial wrinkling of an inflated shallow membrane was obtained. In particular, a membrane in the shape of a sperical annulus was considered. The outer edge of the annulus was assumed to be fixed so that no displacements occur along the outer perimeter. The inner edge is assumed to be clamped to a rigid movable plug. Solutions for the complete stress, strain, and displacement fields under the assumption of inextensional material behavior are presented for the case of pure torsional loads applied to the plug, and for the case of pure axial loads applied to the plug

    Moments of a single entry of circular orthogonal ensembles and Weingarten calculus

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    Consider a symmetric unitary random matrix V=(vij)1i,jNV=(v_{ij})_{1 \le i,j \le N} from a circular orthogonal ensemble. In this paper, we study moments of a single entry vijv_{ij}. For a diagonal entry viiv_{ii} we give the explicit values of the moments, and for an off-diagonal entry vijv_{ij} we give leading and subleading terms in the asymptotic expansion with respect to a large matrix size NN. Our technique is to apply the Weingarten calculus for a Haar-distributed unitary matrix.Comment: 17 page

    System Tests of the ATLAS Pixel Detector

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    The innermost part of the ATLAS (A Toroidal LHC ApparatuS) experiment at the LHC (Large Hadron Collider) will be a pixel detector, which is presently under construction. Once installed into the experimental area, access will be extremely limited. To ensure that the integrated detector assembly operates as expected, a fraction of the detector which includes the power supplies and monitoring system, the optical readout, and the pixel modules themselves, has been assembled and operated in a laboratory setting for what we refer to as system tests. Results from these tests are presented.Comment: 5 Pages, 9 Figures, to appear in Proceedings of the Eleventh Workshop on Electronics for LHC and Future Experiment

    Radiative decays: a new flavour filter

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    Radiative decays of the 13D11^3D_1 orbital excitations of the ρ\rho, ω\omega and ϕ\phi to the scalars f0(1370)f_0(1370), f0(1500)f_0(1500) and f0(1710)f_0(1710) are shown to provide a flavour filter, clarifying the extent of glueball mixing in the scalar states. A complementary approach to the latter is provided by the radiative decays of the scalar mesons to the ground-state vectors ρ\rho, ω\omega and ϕ\phi. Discrimination among different mixing scenarios is strong.Comment: 12 pages, 1 table, 0 figure

    Perioperative Cardiac Arrests

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    Perioperative cardiac arrests represent the most serious complication of anesthesia and surgery. It is believed that the incidence and mortality of cardiac arrest has declined, however, a more recent review questioned whether these rates have changed over the last 5 decades. It is difficult to compare the reports from different epochs, because medical practice has advanced, surgical acuity increased, and patients in extremes of age undergo surgery today. In the present article we review the information regarding the incidence of perioperative cardiac arrests and predictors of survival covering the period since the first comprehensive report by Beecher and Todd in 1954. We focus on our publications that report perioperative cardiac arrest at Mayo Clinic for adult noncardiac surgery, during regional anesthesia, and arrests in our pediatric surgical practice

    Letter to Editor

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    Various methods of manufacturing superconducting accelerating cavities

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    We report on experience in superconducting cavity production methods gained in shaping, joining and thin film coating with various materials and techniques (Pb, Nb, Nb3_{3}Sn, NbN, NbTiN) with emphasis on their potential to reduce mass production costs
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