22 research outputs found

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

    Measurement of charged-particle event shape variables in inclusive root(s)=7 TeV proton-proton interactions with the ATLAS detector

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    The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data

    Measurement of the production cross section for W-bosons in association with jets in pp collisions at √s=7 TeV with the ATLAS detector

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    This Letter reports on a first measurement of the inclusive W + jets cross section in proton–proton collisions at a centre-of-mass energy of 7 TeV at the LHC, with the ATLAS detector. Cross sections, in both the electron and muon decay modes of the W -boson, are presented as a function of jet multiplicity and of the transverse momentum of the leading and next-to-leading jets in the event. Measurements are also presented of the ratio of cross sections σ(W + n)/σ(W + n − 1) for inclusive jet multiplicities n = 1–4. The results, based on an integrated luminosity of 1.3 pb−1, have been corrected for all known detector effects and are quoted in a limited and well-defined range of jet and lepton kinematics. The measured cross sections are compared to particle-level predictions based on perturbative QCD. Next-toleading order calculations, studied here for n 2, are found in good agreement with the data. Leadingorder multiparton event generators, normalized to the NNLO total cross section, describe the data well for all measured jet multiplicities.

    Arrhythmias in Chagasic Cardiomyopathy

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    Chagas disease, a chronic parasitosis caused by the protozoa Trypanosoma cruzi, is an increasing worldwide problem because of the number of cases in endemic areas and the migration of infected individuals to more developed regions. Chagas disease affects the heart through cardiac parasympathetic neuronal depopulation, immune-mediated myocardial injury, parasite persistence in cardiac tissue with secondary antigenic stimulation, and coronary microvascular abnormalities causing myocardial ischemia. A lack of knowledge exists for risk stratification, management, and prevention of ventricular arrhythmias in patients with chagasic cardiomyopathy. Catheter ablation can be effective for the management of recurrent ventricular tachycardia

    El componente educativo en el abordaje integral del asma bronquial The educational component in an integrated approach to bronchial asthma

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    El asma bronquial es una enfermedad inflamatoria crónica de las vías respiratorias cuya prevalencia está aumentando en el mundo. Actualmente no se dispone de un tratamiento curativo, y el objetivo principal de todo abordaje es el control de la enfermedad y la optimización de la calidad de vida de los pacientes. En este sentido, durante las últimas décadas se han estado implementando y evaluando programas de intervención complementarios a los tratamientos médicos convencionales. Gran parte de éstos consisten en intervenciones educativas o incluyen algún tipo de componente educativo. El objetivo del presente trabajo fue analizar las características y el impacto de las intervenciones educativas en el asma, a través de: a) revisión actualizada sobre los diferentes tipos de intervenciones educativas desarrolladas e implementadas para el asma; b) identificación de aspectos comunes a todas estas intervenciones; c) análisis de los hallazgos de la investigación referidos a su impacto sobre la salud y la calidad de vida de los pacientes. Se concluye que las intervenciones educativas son efectivas para mejorar la salud y la calidad de vida de los pacientes con asma, y para reducir el uso y el costo de recursos sanitarios. Estos hallazgos señalan la importancia de incluir el componente educativo como parte esencial del abordaje integral de esta población clínica. Asimismo, la complejidad inherente al proceso educativo pone de manifiesto la necesidad del trabajo conjunto y complementario entre diferentes profesionales de la salud.<br>Bronchial asthma is an inflammatory chronic disease of the respiratory tract whose prevalence is increasing worldwide. Since there is no curative treatment available, the principal objective of every approach is to control the disease and to improve the quality of life of patients. Over the last few decades, intervention programs supplementing conventional medical treatments have been tested and implemented. The majority of such programs consist of educational interventions or include some type of educational component. In this study, we attempted to determine the characteristics and the impact of educational interventions on asthma by means of the following: a) an updated review of the various educational interventions developed and implemented for asthma patients; b) the identification of aspects that are common to all of these interventions; and c) the analysis of the findings in the literature regarding the impact that these interventions have on the health and quality of life of patients. We conclude that educational interventions are effective in improving the health and quality of life of asthma patients, as well as in reducing the use and costs of health resources. These findings indicate the importance of including an educational component as part of an integrated approach to this population. Likewise, the inherent complexity of the educational process highlights the importance of a complementary joint effort including various health professionals

    Burden and typing of rotavirus group A in Latin America and the Caribbean: systematic review and meta-analysis

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    Natural product based leads to fight against leishmaniasis

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