713 research outputs found

    Low Energy States of 3181Ga50^{81}_{31} Ga_{50} : Elements on the Doubly-Magic Nature of 78^{78}Ni

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    Excited levels were attributed to 3181^{81}_{31}Ga50_{50} for the first time which were fed in the β\beta-decay of its mother nucleus 81^{81}Zn produced in the fission of nat^{nat}U using the ISOL technique. We show that the structure of this nucleus is consistent with that of the less exotic proton-deficient N=50 isotones within the assumption of strong proton Z=28 and neutron N=50 effective shell effects.Comment: 4 pages, REVTeX 4, 5 figures (eps format

    Inhibition of post-ganglionic motor transmission in vas deferens by indirectily acting sympathomimetic drugs

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    Usando um campo elétrico estimulador, com séries curtas de pulsos (menor que 10 por série), a transmissão motora pós-ganglionar nos vasos deferentes de mamíferos foi posteriormente analisada do ponto de vista farmacológico

    Natural deep eutectic solvents as thermostabilizer for Humicola insolens cutinase

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    As a new generation of green solvents, deep eutectic solvents (DESs) are considered a promising alternative to current harsh organic solvents and find application in many chemical processing methods such as extraction and synthesis. DESs, normally formed by two or more components via various hydrogen bond interactions, offer high potential as medium for biocatalysis reactions where they can improve efficiency by enhancing substrate solubility and the activity and stability of the enzymes. In the current study, the stabilization of Humicola insolens cutinase (HiC) in natural deep eutectic solvents (NADESs) was assessed. The best hydrogen bond donor among sorbitol, xylitol, erythritol, glycerol and ethylene glycol, and the best acceptor among betaine, choline chloride, choline acetate, choline dihydrogen citrate and tetramethylammonium chloride, were selected, evaluating binding energies and molecular orientations through molecular docking simulations, and finally used to prepare NADES aqueous solutions. The effects of component ratio and NADES concentration on HiC thermostability at 90 degrees C were also investigated. The choline dihydrogen citrate:xylitol, in a 1:1 ratio with a 20 wt% concentration, was selected as the best combination in stabilizing HiC, increasing its half-life three-fold

    High-spin states with seniority v=4,4,6 in 119-126Sn

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    The 119-126Sn nuclei have been produced as fission fragments in two reactions induced by heavy ions: 12C+238U at 90 MeV bombarding energy, 18O+208Pb at 85 MeV. Their level schemes have been built from gamma rays detected using the Euroball array. High-spin states located above the long-lived isomeric states of the even- and odd-A 120-126Sn nuclei have been identified. Moreover isomeric states lying around 4.5 MeV have been established in 120,122,124,126Sn from the delayed coincidences between the fission fragment detector SAPhIR and the Euroball array. The states located above 3-MeV excitation energy are ascribed to several broken pairs of neutrons occupying the nu h11/2 orbit. The maximum value of angular momentum available in such a high-j shell, i.e. for mid-occupation and the breaking of the three neutron pairs, has been identified. This process is observed for the first time in spherical nuclei.Comment: 20 pages, 22 figures, 12 tables, accepted for publication in Physical Review

    Search for Fingerprints of Tetrahedral Symmetry in 156Gd^{156}Gd

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    Theoretical predictions suggest the presence of tetrahedral symmetry as an explanation for the vanishing intra-band E2-transitions at the bottom of the odd-spin negative parity band in 156Gd^{156}Gd. The present study reports on experiment performed to address this phenomenon. It allowed to determine the intra-band E2 transitions and branching ratios B(E2)/B(E1) of two of the negative-parity bands in 156Gd^{156}Gd.Comment: presented by Q.T. Doan at XLII Zakopane School of Physics: Breaking Frontiers: Submicron Structures in Physics and Biology, May 2008. 5 pages, minor corrections. To be published in the proceeding

    Modeling the bremsstrahlung emission from converters

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    The bremsstrahlung angular and energy theoretical distributions delivered from W and UCx thick converters are reported. This study is focussed on initial kinetic energies of the electron beam included in the range 30-60 MeV, suitable for the production of large radiative yields able to induce the 238^{238}U fission. These results offer the possibility to evaluate the required shielding for a neutron rich nuclei source

    Study of the N=50 major shell effect close to 78^{78}Ni : First evidence of a weak coupling structure in 83_32^{83}\_{32}Ge_51\_{51} and three-proton configuration states in 81_31^{81}\_{31}Ga_50\_{50}

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    New levels were attributed to 81_31^{81}\_{31}Ga_50\_{50} and 83_32^{83}\_{32}Ge_51\_{51} which were fed by the β\beta-decay of their respective mother nuclei 81_30^{81}\_{30}Zn_51\_{51} and 83_31^{83}\_{31}Ga_52\_{52} produced by fission at the "PARRNe" ISOL set-up installed at the Tandem accelerator of the Institut de Physique Nucl\'eaire, Orsay. We show that the low energy structure of 81_31^{81}\_{31}Ga_50\_{50} and 83_32^{83}\_{32}Ge_51\_{51} can easily be explained within the natural hypothesis of a strong energy gap at N=50 and a doubly-magic character for 78^{78}Ni.Comment: 2 pages, pdf file, To be published in the Proceedings of "International Symposium on Structure of Exotic Nuclei and Nuclear Forces (SENUF 06)", March 2006, Tokyo, Japa

    The High Burden of Malaria in Primary School Children in Southern Malawi.

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    Malaria among school children has received increased attention recently, yet there remain few detailed data on the health and educational burden of malaria, especially in southern Africa. This paper reports a survey among school children in 50 schools in Zomba District, Malawi. Children were assessed for Plasmodium infection, anemia, and nutritional status and took a battery of age-appropriate tests of attention, literacy, and numeracy. Overall, 60.0% of children were infected with Plasmodium falciparum, 32.4% were anemic and 32.4% reported sleeping under a mosquito net the previous night. Patterns of P. falciparum infection and anemia varied markedly by school. In multivariable analysis, higher odds of P. falciparum infection were associated with younger age and being stunted, whereas lower odds were associated with reported net use, higher parental education, and socioeconomic status. The odds of anemia were significantly associated with P. falciparum infection, with a dose-response relationship between density of infection and odds of anemia. No clear relationship was observed between health status and cognitive and educational outcomes. The high burden of malaria highlights the need to tackle malaria among school children
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