237 research outputs found

    Study of odd-mass N=82 isotones with realistic effective interactions

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    The microscopic quasiparticle-phonon model, MQPM, is used to study the energy spectra of the odd Z=5363Z=53 - 63, N=82 isotones. The results are compared with experimental data, with the extreme quasiparticle-phonon limit and with the results of an unrestricted 2s1d0g7/20h11/22s1d0g_{7/2}0h_{11/2} shell model (SM) calculation. The interaction used in these calculations is a realistic two-body G-matrix interaction derived from modern meson-exchange potential models for the nucleon-nucleon interaction. For the shell model all the two-body matrix elements are renormalized by the Q^\hat{Q}-box method whereas for the MQPM the effective interaction is defined by the G-matrix.Comment: Elsevier latex style espart, 26 pages, submitted to Nuclear Physics

    Wearables and Warranties

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    The last few years have seen an explosion of wearable digital health products. Where a doctor’s visit used to be required for a basic check-up, now a patient’s health status is increasingly at his or her fingertips. We have the ability to track fitness levels, monitor lung and heart capacity, check skin temperature, and observe blood pressure with a simple wearable device

    Beta-decay in odd-A and even-even proton-rich Kr isotopes

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    Beta-decay properties of proton-rich odd-A and even-even Krypton isotopes are studied in the framework of a deformed selfconsistent Hartree-Fock calculation with density-dependent Skyrme forces, including pairing correlations between like nucleons in BCS approximation. Residual spin-isospin interactions are consistently included in the particle-hole and particle-particle channels and treated in Quasiparticle Random Phase Approximation. The similarities and differences in the treatment of even-even and odd-A nuclei are stressed. Comparison to available experimental information is done for Gamow-Teller strength distributions, summed strengths, and half-lives. The dependence of these observables on deformation is particularly emphasized in a search for signatures of the shape of the parent nucleus.Comment: 29 pages, 16 figure

    Ground and excited states Gamow-Teller strength distributions of iron isotopes and associated capture rates for core-collapse simulations

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    This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for 54,55,56^{54,55,56}Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic \textit{state-by-state} calculation of GT strength functions and stellar capture rates which greatly increases the reliability of the results. For the first time experimental deformation of nuclei are taken into account. In the core of massive stars isotopes of iron, 54,55,56^{54,55,56}Fe, are considered to be key players in decreasing the electron-to-baryon ratio (YeY_{e}) mainly via electron capture on these nuclide. The structure of the presupernova star is altered both by the changes in YeY_{e} and the entropy of the core material. Results are encouraging and are compared against measurements (where possible) and other calculations. The calculated electron capture rates are in overall good agreement with the shell model results. During the presupernova evolution of massive stars, from oxygen shell burning stages till around end of convective core silicon burning, the calculated electron capture rates on 54^{54}Fe are around three times bigger than the corresponding shell model rates. The calculated positron capture rates, however, are suppressed by two to five orders of magnitude.Comment: 18 pages, 12 figures, 10 table

    The merit of high-frequency data in portfolio allocation

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    This paper addresses the open debate about the usefulness of high-frequency (HF) data in large-scale portfolio allocation. Daily covariances are estimated based on HF data of the S&P 500 universe employing a blocked realized kernel estimator. We propose forecasting covariance matrices using a multi-scale spectral decomposition where volatilities, correlation eigenvalues and eigenvectors evolve on different frequencies. In an extensive out-of-sample forecasting study, we show that the proposed approach yields less risky and more diversified portfolio allocations as prevailing methods employing daily data. These performance gains hold over longer horizons than previous studies have shown

    Developmental expression of orphan g protein-coupled receptor 50 in the mouse brain

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    [Image: see text] Mental disorders have a complex etiology resulting from interactions between multiple genetic risk factors and stressful life events. Orphan G protein-coupled receptor 50 (GPR50) has been identified as a genetic risk factor for bipolar disorder and major depression in women, and there is additional genetic and functional evidence linking GPR50 to neurite outgrowth, lipid metabolism, and adaptive thermogenesis and torpor. However, in the absence of a ligand, a specific function has not been identified. Adult GPR50 expression has previously been reported in brain regions controlling the HPA axis, but its developmental expression is unknown. In this study, we performed extensive expression analysis of GPR50 and three protein interactors using rt-PCR and immunohistochemistry in the developing and adult mouse brain. Gpr50 is expressed at embryonic day 13 (E13), peaks at E18, and is predominantly expressed by neurons. Additionally we identified novel regions of Gpr50 expression, including brain stem nuclei involved in neurotransmitter signaling: the locus coeruleus, substantia nigra, and raphe nuclei, as well as nuclei involved in metabolic homeostasis. Gpr50 colocalizes with yeast-two-hybrid interactors Nogo-A, Abca2, and Cdh8 in the hypothalamus, amygdala, cortex, and selected brain stem nuclei at E18 and in the adult. With this study, we identify a link between GPR50 and neurotransmitter signaling and strengthen a likely role in stress response and energy homeostasis

    Misuse made plain: Evaluating concerns about neuroscience in national security

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    In this open peer commentary, we categorize the possible “neuroscience in national security” definitions of misuse of science and identify which, if any, are uniquely presented by advances in neuroscience. To define misuse, we first define what we would consider appropriate use: the application of reasonably safe and effective technology, based on valid and reliable scientific research, to serve a legitimate end. This definition presents distinct opportunities for assessing misuse: misuse is the application of invalid or unreliable science, or is the use of reliable scientific methods to serve illegitimate ends. Ultimately, we conclude that while national security is often a politicized issue, assessing the state of scientific progress should not be

    Supersymmetry and neutrinoless double beta decay

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    Neutrinoless double beta decay (0 nu beta beta) induced by superparticle exchange is investigated. Such a supersymmetric (SUSY) mechanism of 0 nu beta beta decay arises within SUSY theories with R-parity nonconservation (R(p)). We consider the minimal supersymmetric standard model (MSSM) with explicit R(p) terms in the superpotential (R(p) MSSM). The decay rate for the SUSY mechanism of 0 nu beta beta decay is calculated. Numerical values for nuclear matrix elements for the experimentally most interesting isotopes are calculated within the proton-neutron quasiparticle random phase approximation. Constraints on the R(p) MSSM parameter space are extracted from current experimental half-life limits. The most stringent limits are derived from data on Ge-76. It is shown that these constraints are more stringent than those from other low-energy processes and are competitive with or even more stringent than constraints expected from accelerator searches
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