252 research outputs found

    Relativistic description of 3He(e,e'p)2H

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    The Relativistic Distorted-Wave Impulse Approximation is used to describe the 3^3He(e,epe,e^\prime p)2^2H process. We describe the 3^3He nucleus within the adiabatic hyperspherical expansion method with realistic nucleon-nucleon interactions. The overlap between the 3^3He and the deuteron wave functions can be accurately computed from a three-body calculation. The nucleons are described by solutions of the Dirac equation with scalar and vector (S-V) potentials. The wave function of the outgoing proton is obtained by solving the Dirac equation with a S-V optical potential fitted to elastic proton scattering data on the residual nucleus. Within this theoretical framework, we compute the cross section of the reaction and other observables like the transverse-longitudinal asymmetry, and compare them with the available experimental data measured at JLab.Comment: 4 pages, 3 figures. Proceedings of the 21st European Few Body Conference held in Salamanca (Spain) in August-September 201

    Relativistic versus Nonrelativistic Optical Potentials in A(e,e'p)B Reactions

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    We investigate the role of relativistic and nonrelativistic optical potentials used in the analysis of (e,epe,e'p) data. We find that the relativistic calculations produce smaller (e,epe,e'p) cross sections even in the case in which both relativistic and nonrelativistic optical potentials fit equally well the elastic proton--nucleus scattering data. Compared to the nonrelativistic impulse approximation, this effect is due to a depletion in the nuclear interior of the relativistic nucleon current, which should be taken into account in the nonrelativistic treatment by a proper redefinition of the effective current operator.Comment: Added one new figure, the formalism section has been enlarged and the list of references updated. Added one appendix. This version will appear in Phys. Rev. C. Revtex 3.0, 6 figures (not included). Full postscript version of the file and figures available at http://www.nikhefk.nikhef.nl/projects/Theory/preprints

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Perfil dos bolsistas de produtividade do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) na área de Medicina Veterinária

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    No presente estudo, submeteram-se dados da população de bolsistas de produtividade do Comitê de Medicina Veterinária do Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ao cálculo de índices cientométricos, em um esforço para avaliar o perfil de pesquisadores de diferentes níveis perante vários parâmetros. Outras variáveis, como o local de formação, gênero, local de trabalho e formação de recursos humanos foram também anotados e avaliados. Há uma clara predominância do gênero masculino (72,37%), os quais se encontram em sua grande maioria radicados nas regiões Sul e Sudeste do país. A maioria dos bolsistas concluiu seu doutorado no Brasil. Dentre os parâmetros de produção analisados, a formação de recursos humanos é alta em todos os níveis; dentre as variáveis cientométricas, os índices de citações e o índice h são decrescentes do nível mais alto (PQ-1A) ao nível 2; todavia, a variação intragrupos é muito alta para estes e outros derivado do índice h. Uma modificação do índice H, o índice AWCR, em que o cálculo leva em conta a idade dos artigos publicados e citados, parece mais adequado à estratificação dos bolsistas. No âmbito geral, estudos deste tipo poderiam ser repetidos no médio prazo com vistas a aprimorar as fórmulas de ranqueamento de bolsistas

    Thematic characterization of research on Information Science in Brazil from 2000-2009

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    Este artículo tiene por objetivo analizar cuáles han sido los principales temas de interés en el campo de la investigación científica dentro del área de la Ciencia de la Información en Brasil a lo largo de la primera década de este siglo (2000-2009). Para ello se ha analizado el contenido de la producción científica publicada en cuatro de las principales revistas nacionales de la disciplina: Ciência da Informação, DataGramaZero, Perspectivas em Ciência da Informação y Transinformação. La metodología aplicada se basa en el análisis de co-ocurrencia de palabras-clave y en la representación e interpretación de los resultados por medio del análisis de redes sociales. Para dotar de un marco de interpretación a los resultados obtenidos se propone una comparación con las áreas temáticas propuestas por la Associação Nacional de Pesquisa e Pós-Graduação em Ciência da Informação en sus Grupos de Trabajo por tratarse de un espacio institucionalizado en donde, por consenso, se debate la investigación en la Ciencia de la Información brasileña. Se concluye en que es el estudio de la propia disciplina la que acapara los mayores esfuerzos de investigación

    Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

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    BACKGROUND: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control. METHODS: Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights. FINDINGS: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease. INTERPRETATION: International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems

    Measurements of differential production cross sections for a Z boson in association with jets in pp collisions at root s=8 TeV

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    Search for leptophobic Z ' bosons decaying into four-lepton final states in proton-proton collisions at root s=8 TeV

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    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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    Search for heavy resonances decaying into a vector boson and a Higgs boson in final states with charged leptons, neutrinos, and b quarks

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