25,692 research outputs found

    Weak decays of medium and heavy Lambda-hypernuclei

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    We have made a new evaluation of the Lambda decay width in nuclear matter within the Propagator Method. Through the Local Density Approximation it is possible to obtain results in finite nuclei. We have also studied the dependence of the widths on the N-N and Lambda-N short range correlations. Using reasonable values for the parameters that control these correlations, as well as realistic nuclear densities and Lambda wave functions, we reproduce, for the first time, the experimental non-mesonic widths in a wide range of mass numbers (from medium to heavy hypernuclei).Comment: 22 pages, including 5 figure

    Phase diagram and surface tension in the three-flavor Polyakov-quark-meson model

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    We obtain the in-medium effective potential of the three-flavor Polyakov-Quark-Meson model as a real function of real variables in the Polyakov loop variable, to allow for the study of all possible minima of the model. At finite quark chemical potential, the real and imaginary parts of the effective potential, in terms of the Polyakov loop variables, are made apparent, showing explicitly the fermion sign problem of the theory. The phase diagram and other equilibrium observables, obtained from the real part of the effective potential, are calculated in the mean-field approximation. The obtained results are compared to those found with the so-called saddle-point approach. Our procedure also allows the calculation of the surface tension between the chirally broken and confined phase, and the chirally restored and deconfined phase. The values of surface tension we find for low temperatures are very close to the ones recently found for two-flavor chiral models. Some consequences of our results for the early Universe, for heavy-ion collisions, and for proto-neutron stars are briefly discussed.Comment: 17 pages, 6 figures. V2: typos fixed, references adde

    Direct 3D Tomographic Reconstruction and Phase-Retrieval of Far-Field Coherent Diffraction Patterns

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    We present an alternative numerical reconstruction algorithm for direct tomographic reconstruction of a sample refractive indices from the measured intensities of its far-field coherent diffraction patterns. We formulate the well-known phase-retrieval problem in ptychography in a tomographic framework which allows for simultaneous reconstruction of the illumination function and the sample refractive indices in three dimensions. Our iterative reconstruction algorithm is based on the Levenberg-Marquardt algorithm. We demonstrate the performance of our proposed method with simulation studies

    Prebiotic, Probiotic, and Synbiotic Supplementation in Chronic Kidney Disease: A Systematic Review and Meta-analysis

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    Gut dysbiosis has been implicated in the pathogenesis of chronic kidney disease (CKD). Restoring gut microbiota with prebiotic, probiotic, and synbiotic supplementation has emerged as a potential therapeutic intervention but has not been systematically evaluated in the CKD population.This is a systematic review. A structured search of MEDLINE, CINAHL, EMBASE, Cochrane Central Register of Controlled Trials, and the International Clinical Trials Register Search Portal was conducted for articles published since inception until July 2017. Included studies were randomized controlled trials investigating the effects of prebiotic, probiotic, and/or synbiotic supplementation (>1\ua0week) on uremic toxins, microbiota profile, and clinical and patient-centered outcomes in adults and children with CKD.Sixteen studies investigating 645 adults met the inclusion criteria; 5 investigated prebiotics, 6 probiotics, and 5 synbiotics. The quality of the studies (Grades of Recommendation, Assessment, Development and Evaluation) ranged from moderate to very low. Prebiotic, probiotic, and synbiotic supplementation may have led to little or no difference in serum urea (9 studies, 345 participants: mean difference [MD] -0.30\ua0mmol/L, 95% confidence interval [CI] -2.20 to 1.61, P\ua0=\ua0.76, I\ua0=\ua053%), indoxyl sulfate (4 studies, 144 participants: MD -0.02\ua0mg/dL, 95% CI -0.09 to 0.05, P\ua0=\ua0.61, I\ua0=\ua00%), and p-cresyl sulfate (4 studies, 144 participants: MD -0.13\ua0mg/dL, 95% CI -0.41 to 0.15, P\ua0=\ua0.35, I\ua0=\ua00%). Prebiotic supplementation may have slightly reduced serum urea concentration (4 studies, 105 participants: MD -2.23\ua0mmol/L, 95% CI -3.83 to -0.64, P\ua0=\ua0.006, I\ua0=\ua011). Of the 2 studies investigating microbiota changes, synbiotic interventions significantly increased Bifidobacterium. Supplement effects on clinical outcomes were uncertain.There is limited evidence to support the use of prebiotics, probiotics, and/or synbiotics in CKD management

    Multi-Kˉ\bar{K} nuclei and kaon condensation

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    We extend previous relativistic mean-field (RMF) calculations of multi-Kˉ\bar K nuclei, using vector boson fields with SU(3) PPV coupling constants and scalar boson fields constrained phenomenologically. For a given core nucleus, the resulting Kˉ\bar K separation energy BKˉB_{\bar K}, as well as the associated nuclear and Kˉ\bar K-meson densities, saturate with the number κ\kappa of Kˉ\bar K mesons for κ>κsat10\kappa > \kappa_{\rm sat} \sim 10. Saturation appears robust against a wide range of variations, including the RMF nuclear model used and the type of boson fields mediating the strong interactions. Because BKˉB_{\bar K} generally does not exceed 200 MeV, it is argued that multi-Kˉ\bar K nuclei do not compete with multihyperonic nuclei in providing the ground state of strange hadronic configurations and that kaon condensation is unlikely to occur in strong-interaction self-bound strange hadronic matter. Last, we explore possibly self-bound strange systems made of neutrons and Kˉ0{\bar K}^0 mesons, or protons and KK^- mesons, and study their properties.Comment: 21 pages, 8 figures, revised text and reference

    The atomic orbitals of the topological atom

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    The effective atomic orbitals have been realized in the framework of Bader’s atoms in molecules theory for a general wavefunction. This formalism can be used to retrieve from any type of calculation a proper set of orthonormalized numerical atomic orbitals, with occupation numbers that sum up to the respective Quantum Theory of Atoms in Molecules (QTAIM) atomic populations. Experience shows that only a limited number of effective atomic orbitals exhibit significant occupation numbers. These correspond to atomic hybrids that closely resemble the core and valence shells of the atom. The occupation numbers of the remaining effective orbitals are almost negligible, except for atoms with hypervalent character. In addition, the molecular orbitals of a calculation can be exactly expressed as a linear combination of this orthonormalized set of numerical atomic orbitals, and the Mulliken population analysis carried out on this basis set exactly reproduces the original QTAIM atomic populations of the atoms. Approximate expansion of the molecular orbitals over a much reduced set of orthogonal atomic basis functions can also be accomplished to a very good accuracy with a singular value decomposition procedure

    PEA‐15 (Phosphoprotein Enriched in Astrocytes 15) Is a Protective Mediator in the Vasculature and Is Regulated During Neointimal Hyperplasia

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    This work was supported by a grant from the Medical Research Council, UK (MR/K012789/1). Additional information can be downloaded from the publisher's websitePeer reviewedPublisher PD
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