1,862 research outputs found

    Effects of scale in predicting global structural response

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    Analytical techniques for scale-up effects were reviewed. The advantages and limitations of applying the principles of similitude to composite structures is summarized and illustrated by simple examples. An analytical procedure was formulated to design scale models of an axially compressed composite cylinder. A building-block approach was outlined where each structural detail is analyzed independently and the probable failure sequence of a selected component is predicted, taking into account load redistribution subsequent to first element failure. Details of this building-block approach are under development

    Supersymmetry in the Standard Model

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    We prove that the bosons and massless fermions of one generation of the standard model are supersymmetric partners of each other. Except for one additional auxilliary vector boson, there are no other SUSY particles.Comment: RevTex, 6 pages, uuencoded tar compressed fil

    Particle Spectrum of the Supersymmetric Standard Model from the Massless Excitations of a Four Dimensional Superstring

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    A superstring action is quantised with Neveu Schwarz(NS) and Ramond(R) boundary conditions. The zero mass states of the NS sector are classified as the vector gluons, W-mesons, BÎŒB_{\mu}-mesons and scalars containing Higgs. The fifteen zero mass fermions are obtained from the Ramond sector. A space time supersymmetric Hamiltonian of the Standard Model is presented without any conventional SUSY particles

    Book Review

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    Automated and Interpretable Patient ECG Profiles for Disease Detection, Tracking, and Discovery

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    The electrocardiogram or ECG has been in use for over 100 years and remains the most widely performed diagnostic test to characterize cardiac structure and electrical activity. We hypothesized that parallel advances in computing power, innovations in machine learning algorithms, and availability of large-scale digitized ECG data would enable extending the utility of the ECG beyond its current limitations, while at the same time preserving interpretability, which is fundamental to medical decision-making. We identified 36,186 ECGs from the UCSF database that were 1) in normal sinus rhythm and 2) would enable training of specific models for estimation of cardiac structure or function or detection of disease. We derived a novel model for ECG segmentation using convolutional neural networks (CNN) and Hidden Markov Models (HMM) and evaluated its output by comparing electrical interval estimates to 141,864 measurements from the clinical workflow. We built a 725-element patient-level ECG profile using downsampled segmentation data and trained machine learning models to estimate left ventricular mass, left atrial volume, mitral annulus e' and to detect and track four diseases: pulmonary arterial hypertension (PAH), hypertrophic cardiomyopathy (HCM), cardiac amyloid (CA), and mitral valve prolapse (MVP). CNN-HMM derived ECG segmentation agreed with clinical estimates, with median absolute deviations (MAD) as a fraction of observed value of 0.6% for heart rate and 4% for QT interval. Patient-level ECG profiles enabled quantitative estimates of left ventricular and mitral annulus e' velocity with good discrimination in binary classification models of left ventricular hypertrophy and diastolic function. Models for disease detection ranged from AUROC of 0.94 to 0.77 for MVP. Top-ranked variables for all models included known ECG characteristics along with novel predictors of these traits/diseases.Comment: 13 pages, 6 figures, 1 Table + Supplemen

    Digital library access for illiterate users

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    The problems that illiteracy poses in accessing information are gaining attention from the research community. Issues currently being explored include developing an understanding of the barriers to information acquisition experienced by different groups of illiterate information seekers; creating technology, such as software interfaces, that support illiterate users effectively; and tailoring content to increase its accessibility. We have taken a formative evaluation approach to developing and evaluating a digital library interface for illiterate users. We discuss modifications to the Greenstone platform, describe user studies and outline resulting design implications

    Persistent currents in coupled mesoscopic rings

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    We have analysed the nature of persistent currents in open coupled mesoscopic rings. Our system is comprised of two ideal loops connected to an electron reservoir. We have obtained analytical expressions for the persistent current densities in two rings in the presence of a magnetic field. We show that the known even-odd parity effects in isolated single loops have to be generalised for the case of coupled rings. We also show that when the two rings have unequal circumferences, it is possible to observe opposite currents (diamagnetic or paramagnetic) in the two rings for a given Fermi level.Comment: Submitted to PRB. 9 figures availabel on reques

    Temperature enhanced persistent currents and "ϕ0/2\phi_0/2 periodicity"

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    We predict a non-monotonous temperature dependence of the persistent currents in a ballistic ring coupled strongly to a stub in the grand canonical as well as in the canonical case. We also show that such a non-monotonous temperature dependence can naturally lead to a ϕ0/2\phi_0/2 periodicity of the persistent currents, where ϕ0\phi_0=h/e. There is a crossover temperature T∗T^*, below which persistent currents increase in amplitude with temperature while they decrease above this temperature. This is in contrast to persistent currents in rings being monotonously affected by temperature. T∗T^* is parameter-dependent but of the order of Δu/π2kB\Delta_u/\pi^2k_B, where Δu\Delta_u is the level spacing of the isolated ring. For the grand-canonical case T∗T^* is half of that for the canonical case.Comment: some typos correcte

    Alterations in carotid baroreflex control of arterial blood pressure during the menstrual cycle in young women [abstract]

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    Limited studies have suggested that menstrual cycle variations in sex hormones may influence arterial baroreflex control of heart rate (HR) and sympathetic nerve activity, however, results are equivocal. In addition, the baroreflex control of blood pressure (BP) has not been directly examined as pharmacological perturbations were mainly used to assess baroreflex function

    Thermofield Dynamics of the Heterotic String - Physical Aspects of the Thermal Duality -

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    The thermofield dynamics of the D = 10 heterotic thermal string theory is described in proper reference to the thermal duality symmetry as well as the thermal stability of modular invariance in association with the global phase structure of the D = 10 heterotic thermal string ensemble.Comment: 8 pages, LaTeX, Minor correction
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