159 research outputs found

    Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

    Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in sqrt{s} = 7 TeV pp collisions using 1 fb-1 of ATLAS data

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    We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04 fb^-1 of proton-proton collision data at sqrt{s} = 7 TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross-section of new physics within the kinematic requirements of the search. The results are interpreted as limits on the parameters of the minimal supergravity framework, limits on cross-sections of simplified models with specific squark and gluino decay modes, and limits on parameters of a model with bilinear R-parity violation.Comment: 18 pages plus author list (30 pages total), 9 figures, 4 tables, final version to appear in Physical Review

    Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

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    This paper constructs the reduction of heterotic MM-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe

    Measurement of tau polarization in W->taunu decays with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

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    In this paper, a measurement of tau polarization in W->taunu decays is presented. It is measured from the energies of the decay products in hadronic tau decays with a single final state charged particle. The data, corresponding to an integrated luminosity of 24 pb^-1, were collected by the ATLAS experiment at the Large Hadron Collider in 2010. The measured value of the tau polarization is Ptau = -1.06 +/- 0.04 (stat) + 0.05 (syst) - 0.07 (syst), in agreement with the Standard Model prediction, and is consistent with a physically allowed 95% CL interval [-1,-0.91]. Measurements of tau polarization have not previously been made at hadron colliders.Comment: 10 pages plus author list (25 pages total), 4 figures, 4 tables, revised author list, matches published EPJC versio

    Efeito da escala de produção nos resultados econômicos da produção de leite B no estado de São Paulo

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    Este estudo avaliou os índices zootécnicos e produtivos, os custos de produção e a rentabilidade de quatro sistemas de produção de leite tipo B do Estado de São Paulo, que usam o sistema de pastejo intensivo como alimentação volumosa do rebanho no período do verão. Os quatro sistemas selecionados foram: sistema EMBRAPA/CPPSE, dois sistemas de produção particulares da região de São Carlos e um sistema localizado em São João da Boa Vista. O critério para escolha dos sistemas particulares foi ter perfis tecnológico e produtivo semelhantes aos do sistema EMBRAPA. Os dados coletados incluíram os índices zootécnicos e os recursos disponíveis de cada sistema. Obtidos os índices zootécnicos, os rebanhos foram estabilizados para permitir análises descritivas das características estudadas nos sistemas. Os resultados obtidos permitiram concluir que alta produtividade nem sempre significa maior lucro e que a escala de produção influenciou o custo total do litro de leite e, portanto, o lucro dos sistemas.This study evaluated the zootechnic and productive indexes, the production costs and the profit of four type B milk production systems in the State of São Paulo, Brazil, that use intensive pasture grazing as the forage source for the cattle during the summer. The four selected systems were: EMBRAPA/CPPSE system and two private production systems of São Carlos region, and one system located in São João da Boa Vista city. The criterion for the private systems selection was to have similar technology and productive profiles as the EMBRAPA system. The collection data included zootechnical index and available recourses for every system. Once the zootechnical index was obtained, the herd was stabilized to allow descriptive analyses of studied characteristics in the systems. The obtained results allowed to conclude that high productivity does not mean greater profit and that the production scale influenced the total cost per litre of milk and, therefore, the profit of the systems

    Readiness of the ATLAS liquid argon calorimeter for LHC collisions

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    The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing performance, electronics noise, and gain stability are presented. High energy deposits from radiative cosmic muons and beam splash events allow to check the intrinsic constant term of the energy resolution. The uniformity of the electromagnetic barrel calorimeter response along eta (averaged over phi) is measured at the percent level using minimum ionizing cosmic muons. Finally, studies of electromagnetic showers from radiative muons have been used to cross-check the Monte Carlo simulation. The performance results obtained using the ATLAS readout, data acquisition, and reconstruction software indicate that the liquid argon calorimeter is well-prepared for collisions at the dawn of the LHC era.ATLAS Collaboration, for complete list of authors see http://dx.doi.org/10.1140/epjc/s10052-010-1354-y</p

    The expression of VDACs and Bcl2 family genes in pituitary adenomas : clinical correlations and postsurgical outcomes

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    Introduction: Pituitary adenomas (PAs) are benign tumors with high prevalence and, occasionally, aggressive course. The tumorigenesis of these lesions is not completely understood at the molecular level. BAK1 and BAX proteins play fundamental roles in apoptosis and seem to interact with VDAC proteins, whose expressions have been markedly altered in cancer, impacting their prognosis. Objective: to evaluate the gene expression of VDAC1, VDAC2, BAK1 and BAX and their association with clinical and imaging characteristics in PA. Methods: Clinical-epidemiological data were collected from 117 tumor samples from patients affected by PA. Invasiveness was assessed by the Knosp scale. Gene expression was examined by real-time PCR. Relative expression analysis was performed by 2^(-DDCt) method. Results: The sample was mainly composed of women (69/117 - 57.2%). Tumor subtypes observed were Non-Functioning (NF) (73/117 - 62.4%), Acromegaly (24/117 - 20.5%) and Cushing's Disease (CD) (20/117 - 17.1%). Compared to normal tissue, there was a significant reduction in VDAC1 expression in the Acromegaly (p=0.029) and NF (p=0.002) groups. BAX expression was lower in all groups (p <0.001; p=0.007; P =0.005). No difference was found in VDAC2 and BAK1 expression, compared to normal pituitary. Overexpression of VDAC2 occurred in PAs with post-surgical regrowth (p=0.042). A strongly negative correlation was observed in BAX and BAK1 expression in CD. Conclusion: The results indicated that downregulations of VDAC1 and BAX may be related to resistance to apoptosis. In contrast, overexpression of VDAC2 in regrowing PAs suggests an antiapoptotic role for this gene. In summary, the genes evaluated might be involved in the biopathology of PAs

    Nutritional evaluation of elephant-grass silages with byproduct of annato

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    The objective of the present study was to evaluate the nutritional value of elephant-grass silages containing annato byproduct. Twenty intact rams were distributed in a complete randomized block design with five diets (0; 4; 8; 12 and 16% annato byproduct in the silage) and four replications and used to estimate the intake, apparent nutrient digestibility, content of total digestible nutrients and nitrogen balance. The addition of annato byproduct raised the intakes of dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), total carbohydrates (TC), non-fibrous carbohydrates (NFC) and total digestible nutrients (TDN), in body weight (%BW) and in metabolic weight (g kg-1BW0.75). The digestibilities of DM (55.95%), OM (58.19%), CP (45.34%), NDF (52.79%), ADF (45.79%), EE (34.96%) and NFC (99.86%) were not influenced by the addition of annato byproduct. The inclusion of annato byproduct in elephant-grass silage increased digestibility of total carbohydrates, the TDN content and the nitrogen balance. The aditions of annato byproduct at levels up to 16% of the elephant grass silage natural matter improves nutrient intake and nitrogen balance.Objetivou-se avaliar o valor nutritivo de silagens de capim-elefante contendo subproduto do processamento do urucum. Vinte ovinos machos, não-castrados, foram distribuídos em delineamento inteiramente casualizado com cinco dietas (0; 4; 8; 12 e 16% de subproduto de urucum na silagem) e quatro repetições, e utilizados para estimar o consumo, a digestibilidade aparente de nutrientes, o teor de nutrientes digestíveis totais e o balanço de nitrogênio. A adição de subproduto de urucum elevou os consumos de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), extrato etéreo (EE), carboidratos não-fibrosos (CNF), carboidratos totais e nutrientes digestíveis totais (NDT), tanto em relação ao peso vivo (%PV) quanto em relação ao peso metabólico (g kg-1PV0,75). As digestibilidades de MS (55,95%), MO (58,19%), PB (45,34%), FDN (52,79%), FDA (45,79%), EE (34,96%) e CNF (99,86%) não foram influenciadas pela adição de subproduto de urucum. A inclusão de subproduto de urucum na silagem de capim-elefante promoveu aumento na digestibilidade dos carboidratos totais, no teor de NDT e no balanço de nitrogênio. A adição de subproduto de urucum em níveis de até 16% da matéria natural na ensilagem de capim-elefante melhora o consumo de nutrientes e o balanço de nitrogênio
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