218 research outputs found

    Effects of glucagon-like peptide-1 receptor agonists on weight loss: systematic review and meta-analyses of randomised controlled trials

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    Objective To determine whether treatment with agonists of glucagon-like peptide-1 receptor (GLP-1R) result in weight loss in overweight or obese patients with or without type 2 diabetes mellitus

    Kartlegging av Stillehavsøsters (Crassostrea gigas) - Bestandskartlegging Karmøy - Svenskegrensa 2017 - 2019

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    Med endringer i havmiljøene, vil ogsü dynamikken i marine økosystemer kunne endres og nye arter vil kunne etableres seg i norske farvann slik som stillehavsøsters ( Magallana gigas ). Arten etablerte seg allerede pü 1990 tallet i Vadehavet pü den danske vestkysten og fra 2006 spredde den seg videre langs skagerrakkysten. Arten er definert som fremmed, invasiv og er plassert i risikokategorien Høy Økologisk Risiko, pü grunn av spredningspotensiale og økologisk effekt (Artsdatabanken). Stillehavsøsters anses om bioinvasiv og er en art som endrer de økosystemene hvor den etablere seg, og som vil kunne ha en direkte negativ effekt pü stedegne arter, som for eksempel blüskjell og flatøsters. Arten har ogsü uønskede negative sosioøkonomiske effekter knyttet til forringelse av strender og andre naturomrüder.publishedVersio

    Neutron-induced background by an alpha-beam incident on a deuterium gas target and its implications for the study of the 2H(alpha,gamma)6Li reaction at LUNA

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    The production of the stable isotope Li-6 in standard Big Bang nucleosynthesis has recently attracted much interest. Recent observations in metal-poor stars suggest that a cosmological Li-6 plateau may exist. If true, this plateau would come in addition to the well-known Spite plateau of Li-7 abundances and would point to a predominantly primordial origin of Li-6, contrary to the results of standard Big Bang nucleosynthesis calculations. Therefore, the nuclear physics underlying Big Bang Li-6 production must be revisited. The main production channel for Li-6 in the Big Bang is the 2H(alpha,gamma)6Li reaction. The present work reports on neutron-induced effects in a high-purity germanium detector that were encountered in a new study of this reaction. In the experiment, an {\alpha}-beam from the underground accelerator LUNA in Gran Sasso, Italy, and a windowless deuterium gas target are used. A low neutron flux is induced by energetic deuterons from elastic scattering and, subsequently, the 2H(d,n)3He reaction. Due to the ultra-low laboratory neutron background at LUNA, the effect of this weak flux of 2-3 MeV neutrons on well-shielded high-purity germanium detectors has been studied in detail. Data have been taken at 280 and 400 keV alpha-beam energy and for comparison also using an americium-beryllium neutron source.Comment: Submitted to EPJA; 13 pages, 8 figure

    First Direct Measurement of the ^{17}O(p,\gamma)^{18}F Reaction Cross-Section at Gamow Energies for Classical Novae

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    Classical novae are important contributors to the abundances of key isotopes, such as the radioactive ^{18}F, whose observation by satellite missions could provide constraints on nucleosynthesis models in novae. The ^{17}O(p,\gamma)^{18}F reaction plays a critical role in the synthesis of both oxygen and fluorine isotopes but its reaction rate is not well determined because of the lack of experimental data at energies relevant to novae explosions. In this study, the reaction cross section has been measured directly for the first time in a wide energy range Ecm = 200 - 370 keV appropriate to hydrogen burning in classical novae. In addition, the E=183 keV resonance strength, \omega \gamma=1.67\pm0.12 \mueV, has been measured with the highest precision to date. The uncertainty on the ^{17}O(p,\gamma)^{18}F reaction rate has been reduced by a factor of 4, thus leading to firmer constraints on accurate models of novae nucleosynthesis.Comment: accepted by Phys. Rev. Let

    Preparation and characterisation of isotopically enriched Ta2_2O5_5 targets for nuclear astrophysics studies

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    The direct measurement of reaction cross sections at astrophysical energies often requires the use of solid targets of known thickness, isotopic composition, and stoichiometry that are able to withstand high beam currents for extended periods of time. Here, we report on the production and characterisation of isotopically enriched Ta2_2O5_5 targets for the study of proton-induced reactions at the Laboratory for Underground Nuclear Astrophysics facility of the Laboratori Nazionali del Gran Sasso. The targets were prepared by anodisation of tantalum backings in enriched water (up to 66% in 17^{17}O and up to 96% in 18^{18}O). Special care was devoted to minimising the presence of any contaminants that could induce unwanted background reactions with the beam in the energy region of astrophysical interest. Results from target characterisation measurements are reported, and the conclusions for proton capture measurements with these targets are drawn.Comment: accepted to EPJ
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