7,197 research outputs found

    Dolichol Monophosphate Glucose: An Intermediate in Glucose Transfer in Liver

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    Potential of a Neutrino Detector in the ANDES Underground Laboratory for Geophysics and Astrophysics of Neutrinos

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    The construction of the Agua Negra tunnels that will link Argentina and Chile under the Andes, the world longest mountain range, opens the possibility to build the first deep underground labo- ratory in the Southern Hemisphere. This laboratory has the acronym ANDES (Agua Negra Deep Experiment Site) and its overburden could be as large as \sim 1.7 km of rock, or 4500 mwe, providing an excellent low background environment to study physics of rare events like the ones induced by neutrinos and/or dark matter. In this paper we investigate the physics potential of a few kiloton size liquid scintillator detector, which could be constructed in the ANDES laboratory as one of its possible scientific programs. In particular, we evaluate the impact of such a detector for the studies of geoneutrinos and galactic supernova neutrinos assuming a fiducial volume of 3 kilotons as a reference size. We emphasize the complementary roles of such a detector to the ones in the Northern Hemisphere neutrino facilities through some advantages due to its geographical location.Comment: 20 pages, 16 figures and 9 table

    A population-based case-control study on social factors and risk of testicular germ cell tumours

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    Objectives Incidence rates for testicular cancer have risen over the last few decades. Findings of an association between the risk of testicular cancer and social factors are controversial. The association of testicular cancer and different indicators of social factors were examined in this study.<p></p> Design Case–control study.<p></p> Setting Population-based multicentre study in four German regions (city states Bremen and Hamburg, the Saarland region and the city of Essen).<p></p> Participants The study included 797 control participants and 266 participants newly diagnosed with testicular cancer of which 167 cases were classified as seminoma and 99 as non-seminoma. The age of study participants ranged from 15 to 69 years.<p></p> Methods Social position was classified by educational attainment level, posteducational training, occupational sectors according to Erikson-Goldthorpe-Portocarrero (EGP) and the socioeconomic status (SES) on the basis of the International SocioEconomic Index of occupational status (ISEI). ORs and corresponding 95% CIs (95% CIs) were calculated for the whole study sample and for seminoma and non-seminoma separately.<p></p> Results Testicular cancer risk was modestly increased among participants with an apprenticeship (OR=1.7 (95% CI 1.0 to 2.8)) or a university degree (OR=1.6 (95% CI 0.9 to 2.8)) relative to those whose education was limited to school. Analysis of occupational sectors revealed an excess risk for farmers and farm-related occupations. No clear trend was observed for the analyses according to the ISEI-scale.<p></p> Conclusions Social factors based on occupational measures were not a risk factor for testicular cancer in this study. The elevated risk in farmers and farm-related occupations warrants further research including analysis of occupational exposures.<p></p&gt

    Characterization of red wines aged with oak chip in the São Francisco Valley, Brazil.

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    This research aimed to characterize the physicochemical composition of Syrah tropical wines aged with oak chip addition

    Neutrino and antineutrino charge-exchange reactions on 12C

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    We extend the formalism of weak interaction processes, obtaining new expressions for the transition rates, which greatly facilitate numerical calculations, both for neutrino-nucleus reactions and muon capture. Explicit violation of CVC hypothesis by the Coulomb field, as well as development of a sum rule approach for the inclusive cross sections have been worked out. We have done a thorough study of exclusive (ground state) properties of 12^{12}B and 12^{12}N within the projected quasiparticle random phase approximation (PQRPA). Good agreement with experimental data achieved in this way put in evidence the limitations of standard RPA and the QRPA models, which come from the inability of the RPA in opening the p3/2p_{3/2} shell, and from the non-conservation of the number of particles in the QRPA. The inclusive neutrino/antineutrino (ν/ν~\nu/\tilde{\nu}) reactions 12^{12}C(ν,e)12\nu,e^-)^{12}N and 12^{12}C(ν~,e+)12\tilde{\nu},e^+)^{12}B are calculated within both the PQRPA, and the relativistic QRPA (RQRPA). It is found that the magnitudes of the resulting cross-sections: i) are close to the sum-rule limit at low energy, but significantly smaller than this limit at high energies both for ν\nu and ν~\tilde{\nu}, ii) they steadily increase when the size of the configuration space is augmented, and particulary for ν/ν~\nu/\tilde{\nu} energies >200> 200 MeV, and iii) converge for sufficiently large configuration space and final state spin. The quasi-elastic 12^{12}C(ν,μ)12\nu,\mu^-)^{12}N cross section recently measured in the MiniBooNE experiment is briefly discussed. We study the decomposition of the inclusive cross-section based on the degree of forbiddenness of different multipoles. A few words are dedicated to the ν/ν~\nu/\tilde{\nu}-12^{12}C charge-exchange reactions related with astrophysical applications.Comment: 21 pages, 13 figures, 1 table, submitted to Physical Review

    Probing Low Energy Neutrino Backgrounds with Neutrino Capture on Beta Decaying Nuclei

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    We study the interaction of low energy neutrinos on nuclei that spontaneously undergo beta decay showing that the product of the cross section times neutrino velocity takes values as high as 10^{-42} cm^2 c for some specific nuclei that decay via allowed transitions. The absence of energy threshold and the value of the cross section single out these processes as a promising though very demanding approach for future experiments aimed at a direct detection of low energy neutrino backgrounds such as the cosmological relic neutrinos.Comment: Includes a discussion of local relic neutrino density effect on neutrino capture rate. Accepted for publication in JCA

    Weak Long-Ranged Casimir Attraction in Colloidal Crystals

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    We investigate the influence of geometric confinement on the free energy of an idealized model for charge-stabilized colloidal suspensions. The mean-field Poisson-Boltzmann formulation for this system predicts pure repulsion among macroionic colloidal spheres. Fluctuations in the simple ions' distribution provide a mechanism for the macroions to attract each other at large separations. Although this Casimir interaction is long-ranged, it is too weak to influence colloidal crystals' dynamics.Comment: 5 pages 2 figures ReVTe

    Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model

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    A new critical survey is presented of all half-life, decay-energy and branching-ratio measurements related to 20 0+ to 0+ beta decays. Compared with our last review, there are numerous improvements: First, we have added 27 recently published measurements and eliminated 9 references; of particular importance, the new data include a number of high-precision Penning-trap measurements of decay energies. Second, we have used the recently improved isospin symmetry-breaking corrections. Third, our calculation of the statistical rate function now accounts for possible excitation in the daughter atom. Finally, we have re-examined the systematic uncertainty associated with the isospin symmetry-breaking corrections by evaluating the radial-overlap correction using Hartree-Fock radial wave functions and comparing the results with our earlier calculations, which used Saxon-Woods wave functions; the provision for systematic uncertainty has been changed as a consequence. The new corrected Ft values are impressively constant and their average, when combined with the muon liftime, yields the up-down quark-mixing element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, V_{ud} = 0.97425(22). The unitarity test on the top row of the matrix becomes |V_{ud}|^2 + |V_{us}|^2 + |V_{ub}|^2 = 0.99995(61). Both V_{ud} and the unitarity sum have significantly reduced uncertainties compared with our previous survey, although the new value of V_{ud} is statistically consistent with the old one. From these data we also set limits on the possible existence of scalar interactions, right-hand currents and extra Z bosons. Finally, we discuss the priorities for future theoretical and experimental work with the goal of making the CKM unitarity test even more definitive.Comment: 36 pages, 11 tables, 9 figure

    A study of semi-inclusive charmless BπXB \to \pi X decays

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    We study semi-inclusive charmless decays BπXB \to \pi X in detail, such as Bˉ0π±(0)X\bar B^0 \to \pi^{\pm (0)} X, B0π±(0)XB^0 \to \pi^{\pm (0)} X, B±π±(0)XB^{\pm} \to \pi^{\pm (0)} X, where XX does not contain a charm (anti)quark. We find that the process Bˉ0πX\bar B^0 \to \pi^- X (B0π+XB^0 \to \pi^+ X) can be particularly useful for determination of the CKM matrix element Vub|V_{ub}|. We calculate and present the branching ratio (BR) of Bˉ0πX\bar B^0 \to \pi^- X as a function of Vub|V_{ub}|, with an estimate of possible uncertainties. It is expected that the BR is an order of 10410^{-4}. Our estimation indicates that one can phenomenologically determine Vub|V_{ub}| with reasonable accuracy by measuring the BR of Bˉ0πX\bar B^0 \to \pi^- X (B0π+XB^0 \to \pi^+ X).Comment: 18 pages, 7 figures; Revtex; version accepted for publication in Eur. Phys. J.
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