187 research outputs found

    Holter monitoring for syncope: diagnostic yield in different patient groups and impact on device implantation

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    Background: Holter monitoring is routinely used in patients referred for the evaluation of syncope, but its diagnostic value in different patient groups is unclear, as is its impact on device implantation (pacemaker or cardioverter-defibrillator). Aim: To determine the diagnostic yield of Holter monitoring in the routine evaluation of syncope, and its impact on subsequent device implantation. Design: Retrospective record review. Methods: We reviewed all Holter studies in patients referred with syncope between 2000 and 2005. Strict criteria were applied to determine whether a study was diagnostic. The diagnostic value of Holter monitoring (overall and in five subgroups: age, gender, structural heart disease, ejection fraction, medication) and its impact on the implantation of devices, were determined. Results: Of 4877 Holter studies, 826 were performed in patients with syncope (age 72 ± 15 years): 71 (8.6%) were considered to explain the syncope. Structural heart disease, ejection fraction and age were significant predictors of a diagnostic study (all p < 0.01), whereas gender and cardiac medication were not. A device was implanted in 33 patients (4.4%) whose initial Holter did not explain their syncope, after mean 7 months, whereas 45 patients (5.4%) received a pacemaker based on the Holter results (p = 0.32). Discussion: The overall diagnostic yield of Holter monitoring in the evaluation of syncope was 8.6%, with dramatic differences between subgroups. Our data suggest that the impact of Holter monitoring on device implantation is generally overestimate

    Higher order Schrodinger and Hartree-Fock equations

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    The domain of validity of the higher-order Schrodinger equations is analyzed for harmonic-oscillator and Coulomb potentials as typical examples. Then the Cauchy theory for higher-order Hartree-Fock equations with bounded and Coulomb potentials is developed. Finally, the existence of associated ground states for the odd-order equations is proved. This renders these quantum equations relevant for physics.Comment: 19 pages, to appear in J. Math. Phy

    EVALUATION OF THE QUALITY OF AN INTELLIGENT AND SUSTAINABLE TOURIST URBAN SYSTEM IN TLEMCEN

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    This article proposes the evaluation of a tourist urban system "Plateau LallaSetti, Tlemcen" in a global framework for the elaboration of a territorial diagnosis with a view to taking charge of urban complexity. The integrated "Quality Safety Environment" approach, which is very suitable for dealing with the complexity of urban systems, aims to introduce the site to urban sustainability by putting the principles of sustainable development by involving all stakeholders in decision-making through participatory governance by introducing the notion of urban intelligence.This approach guarantees a consensus upstream of the decision-making process, reducing the likelihood of conflict situations linked to contradictory positions of its actors compared the main orientations governing the urban project. Thanks to this integrated QSE evaluation method, which consists of determining the performance threshold of each index relating to the indicators stemming from criteria of the existing system by the quantification of the latter based on an approach of assessment of the environmental impacts integrating the thought "cycle of life " through shared evaluation in consultation (ex ante, in itinere), it will be possible to integrate as much as necessary the temporal dimension of these impacts and to ensure the resilience of the system in corrective or preventive measures undertaken before and after during the design of the urban system to precise temporalities of its life cycle

    Diagnostic Value of Capillary Density at Periungual Capillaroscopy in the Diagnosis of Connective Tissue Disease

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    Our study aims to demonstrate the contribution of quantitative analysis of capillaroscopic study in the early diagnosis of connective tissue diseases. One hundred and fifteen patients were evaluated by capillaroscopy. Raynaud's phenomenon is the most frequently encountered acro-syndrome leading to the request for capillaroscopic examination. capillaroscopy reveals minor dystrophy in 83.5% of patients and major dystrophy in 60% of them. On a quantitative level, 77 patients present, among the four examined fingers, at least one finger with a capillary density &lt;25 capillaries/3mm. For the diagnosis of connective tissue disease, this threshold is statistically significant with an odds ratio of 4.21 (95% CI = 1.47-11.99; p = 0.008). For this same diagnosis, its positive predictive value is 38%, its negative predictive value is 86%. A low capillary density, as a diagnostic test for connective tissue disease, has a sensitivity of 85% and a specificity of 41%. There is no significant difference between the decrease in capillary density for the diagnosis of connective tissue disease for each examined finger in terms of positive predictive value, negative predictive value, sensitivity, and specificit

    Time-Fractional Optimal Control of Initial Value Problems on Time Scales

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    We investigate Optimal Control Problems (OCP) for fractional systems involving fractional-time derivatives on time scales. The fractional-time derivatives and integrals are considered, on time scales, in the Riemann--Liouville sense. By using the Banach fixed point theorem, sufficient conditions for existence and uniqueness of solution to initial value problems described by fractional order differential equations on time scales are known. Here we consider a fractional OCP with a performance index given as a delta-integral function of both state and control variables, with time evolving on an arbitrarily given time scale. Interpreting the Euler--Lagrange first order optimality condition with an adjoint problem, defined by means of right Riemann--Liouville fractional delta derivatives, we obtain an optimality system for the considered fractional OCP. For that, we first prove new fractional integration by parts formulas on time scales.Comment: This is a preprint of a paper accepted for publication as a book chapter with Springer International Publishing AG. Submitted 23/Jan/2019; revised 27-March-2019; accepted 12-April-2019. arXiv admin note: substantial text overlap with arXiv:1508.0075

    The Q^2-Dependence of Nuclear Transparency for Exclusive ρ0\rho^0 Production

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    Exclusive coherent and incoherent electroproduction of the ρ0\rho^0 meson from 1^1H and 14^{14}N targets has been studied at the HERMES experiment as a function of coherence length (lcl_c), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (Q2-Q^2). The ratio of 14^{14}N to 1^1H cross sections per nucleon, known as nuclear transparency, was found to increase (decrease) with increasing coherence length for coherent (incoherent) ρ0\rho^0 electroproduction. For fixed coherence length, a rise of nuclear transparency with Q2Q^2 is observed for both coherent and incoherent ρ0\rho^0 production, which is in agreement with theoretical calculations of color transparency.Comment: 5 pages, 4 figure

    Single-spin asymmetries in semi-inclusive deep-inelastic scattering on a transversely polarized hydrogen target

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    Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering of positrons are measured for the first time with transverse target polarization. The asymmetry depends on the azimuthal angles of both the pion (ϕ\phi) and the target spin axis (ϕS\phi_S) about the virtual photon direction and relative to the lepton scattering plane. The extracted Fourier component \cmpi is a signal of the previously unmeasured quark transversity distribution, in conjunction with the so-called Collins fragmentation function, also unknown. The Fourier component \smpi of the asymmetry arises from a correlation between the transverse polarization of the target nucleon and the intrinsic transverse momentum of quarks, as represented by the previously unmeasured Sivers distribution function. Evidence for both signals is observed, but the Sivers asymmetry may be affected by exclusive vector meson productio

    Flavor decomposition of the sea quark helicity distributions in the nucleon from semi-inclusive deep-inelastic scattering

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    Double-spin asymmetries of semi-inclusive cross sections for the production of identified pions and kaons have been measured in deep-inelastic scattering of polarized positrons on a polarized deuterium target. Five helicity distributions including those for three sea quark flavors were extracted from these data together with re-analyzed previous data for identified pions from a hydrogen target. These distributions are consistent with zero for all three sea flavors. A recently predicted flavor asymmetry in the polarization of the light quark sea appears to be disfavored by the data.Comment: 5 pages, 3 figure

    Nuclear Polarization of Molecular Hydrogen Recombined on a Non-metallic Surface

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    The nuclear polarization of H2\mathrm{H}_2 molecules formed by recombination of nuclear polarized H atoms on the surface of a storage cell initially coated with a silicon-based polymer has been measured by using the longitudinal double-spin asymmetry in deep-inelastic positron-proton scattering. The molecules are found to have a substantial nuclear polarization, which is evidence that initially polarized atoms retain their nuclear polarization when absorbed on this type of surfac
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