308 research outputs found

    Measurement of the top pair production cross section in 8 TeV proton-proton collisions using kinematic information in the lepton plus jets final state with ATLAS

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    A measurement is presented of the ttˉt\bar{t} inclusive production cross-section in pppp collisions at a center-of-mass energy of s=8\sqrt{s}=8 TeV using data collected by the ATLAS detector at the CERN Large Hadron Collider. The measurement was performed in the lepton+jets final state using a data set corresponding to an integrated luminosity of 20.3 fb1^{-1}. The cross-section was obtained using a likelihood discriminant fit and bb-jet identification was used to improve the signal-to-background ratio. The inclusive ttˉt\bar{t} production cross-section was measured to be 260±1(stat.)23+22(syst.)±8(lumi.)±4(beam)260\pm 1{\textrm{(stat.)}} ^{+22}_{-23} {\textrm{(syst.)}}\pm 8{\textrm{(lumi.)}}\pm 4{\mathrm{(beam)}} pb assuming a top-quark mass of 172.5 GeV, in good agreement with the theoretical prediction of 25315+13253^{+13}_{-15} pb. The ttˉ(e,μ)+jetst\bar{t}\to (e,\mu)+{\mathrm{jets}} production cross-section in the fiducial region determined by the detector acceptance is also reported.Comment: Published version, 19 pages plus author list (35 pages total), 3 figures, 2 tables, all figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2013-06

    Dynamic assessment precursors: Soviet ideology, and Vygotsky

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    Fine-Scale Mapping of the 5q11.2 Breast Cancer Locus Reveals at Least Three Independent Risk Variants Regulating MAP3K1

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    A importância da associação obesidade e gravidez

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    Characteristics of the evolution of pregnancy in obese women were studied for their effect on newborn infants. Two control groups were observed - one of normal weight pregnant women, one of obese. The variables selected were: the socio-economic status of the family and the mother's age, height, arm circunference, prepregancy weight, total number of pregnancies, parity, weight gain during pregnancy, obstetric complications, birth weight, and fetal vitality. Results showed that pregnancy in obese women differs from that in normal weight women and that they show a larger incidence of obstetric complications. Children of obese mothers had a higher mortality rate principally in the perinatal period; moreover, there was also a higher rate of prematurity and a higher proportion of overweight babies among obese mothers. As a result, the distribution of the curve of the birth weight of infants of obese morthers was higher than that of infants of normal weight mothers. The conclusion reached was that whenever a pregnant obese woman reduced foot intake, with resultant insufficient weight gain, intrauterine growth was affected. Thus, it follows that pregnancy is not the best time for the obese mother to lose weight; for this reason, it is important that she receive adequate guidance in regard to diet. Obesity, therefore, is a factor contributing to high-risk pregnancy which can affect both mother and child.Foram estudados dois grupos de gestantes, sendo um de grávidas normais e outro de obesas, com a finalidade de reconhecer algumas características da evolução da gravidez, em mulheres obesas, e suas repercussões sobre o concepto. Foram relacionadas as seguintes variáveis: status sócio-econômico familiar, idade, altura, perímetro braquial, peso habitual, número de gestações anteriores, paridade materna, ganho de peso durante a gestação, idade gestacional, intercorrências durante a gestação, peso ao nascer e vitalidade do recém-nascido. Pelos resultados concluiu-se que as gestantes obesas são diferentes das normais e apresentam maior incidência de complicações obstétricas. Os recém-nascidos, filhos de obesas, registraram índice maior de mortalidade, principalmente no período perinatal. Houve maior incidência de prematuridade e de fetos macrossômicos, sendo a curva de distribuição de peso ao nascer diferente da dos recém-nascidos das gestantes normais. A média de peso ao nascer das crianças das gestantes obesas é maior que o das normais. Concluiu-se ainda que toda vez que a gestante obesa sofre restrição alimentar, com ganho de peso inadequado, o crescimento intra-uterino é afetado; não sendo, portanto, a época da gravidez a melhor para a obesa perder peso, mas, ao contrário, ela deveria receber uma orientação alimentar adequada. A obesidade é pois um fator de aumento do risco gravídico, que pode afetar tanto a mãe como o concepto

    On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

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    A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR
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