992 resultados para Job 7:6-7


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A measurement of the top--antitop (tt¯) charge asymmetry is presented using data corresponding to an integrated luminosity of 4.6 fb−1 of LHC pp collisions at a centre-of-mass energy of 7 TeV collected by the ATLAS detector. Events with two charged leptons, at least two jets and large missing transverse momentum are selected. Two observables are studied: AℓℓC based on the identified charged leptons, and Att¯C, based on the reconstructed tt¯ final state. The asymmetries are measured to be AℓℓC=0.024±0.015 (stat.)±0.009 (syst.), Att¯C=0.021±0.025 (stat.)±0.017 (syst.). The measured values are in agreement with the Standard Model predictions.

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The inclusive jet cross-section is measured in proton--proton collisions at a centre-of-mass energy of 7 TeV using a data set corresponding to an integrated luminosity of 4.5 fb−1 collected with the ATLAS detector at the Large Hadron Collider in 2011. Jets are identified using the anti-kt algorithm with radius parameter values of 0.4 and 0.6. The double-differential cross-sections are presented as a function of the jet transverse momentum and the jet rapidity, covering jet transverse momenta from 100 GeV to 2 TeV. Next-to-leading-order QCD calculations corrected for non-perturbative effects and electroweak effects, as well as Monte Carlo simulations with next-to-leading-order matrix elements interfaced to parton showering, are compared to the measured cross-sections. A quantitative comparison of the measured cross-sections to the QCD calculations using several sets of parton distribution functions is performed.

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The tt¯ production cross-section dependence on jet multiplicity and jet transverse momentum is reported for proton--proton collisions at a centre-of-mass energy of 7 TeV in the single-lepton channel. The data were collected with the ATLAS detector at the CERN Large Hadron Collider and comprise the full 2011 data sample corresponding to an integrated luminosity of 4.6 fb−1. Differential cross-sections are presented as a function of the jet multiplicity for up to eight jets using jet transverse momentum thresholds of 25, 40, 60, and 80 GeV, and as a function of jet transverse momentum up to the fifth jet. The results are shown after background subtraction and corrections for all detector effects, within a kinematic range closely matched to the experimental acceptance. Several QCD-based Monte Carlo models are compared with the results. Sensitivity to the parton shower modelling is found at the higher jet multiplicities, at high transverse momentum of the leading jet and in the transverse momentum spectrum of the fifth leading jet. The MC@NLO+HERWIG MC is found to predict too few events at higher jet multiplicities.

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The production of a W boson decaying to eν or μν in association with a W or Z boson decaying to two jets is studied using 4.6 fb−1 of proton--proton collision data at s√=7 TeV recorded with the ATLAS detector at the LHC. The combined WW+WZ cross section is measured with a significance of 3.4σ and is found to be 68±7 (stat.)±19 (syst.) pb, in agreement with the Standard Model expectation of 61.1±2.2 pb. The distribution of the transverse momentum of the dijet system is used to set limits on anomalous contributions to the triple gauge coupling vertices and on parameters of an effective-field-theory model.

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Double-differential three-jet production cross-sections are measured in proton--proton collisions at a centre-of-mass energy of s√=7TeV using the ATLAS detector at the Large Hadron Collider. The measurements are presented as a function of the three-jet mass (mjjj), in bins of the sum of the absolute rapidity separations between the three leading jets (|Y∗|). Invariant masses extending up to 5 TeV are reached for 8<|Y∗|<10. These measurements use a sample of data recorded using the ATLAS detector in 2011, which corresponds to an integrated luminosity of 4.51fb−1. Jets are identified using the anti-kt algorithm with two different jet radius parameters, R=0.4 and R=0.6. The dominant uncertainty in these measurements comes from the jet energy scale. Next-to-leading-order QCD calculations corrected to account for non-perturbative effects are compared to the measurements. Good agreement is found between the data and the theoretical predictions based on most of the available sets of parton distribution functions, over the full kinematic range, covering almost seven orders of magnitude in the measured cross-section values.

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The mass of the top quark is measured in a data set corresponding to 4.6 fb−1 of proton--proton collisions with centre-of-mass energy s√=7 TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top--antitop quark pairs with at least six jets in the final state are selected. The substantial background from multijet production is modelled with data-driven methods that utilise the number of identified b-quark jets and the transverse momentum of the sixth leading jet, which have minimal correlation. The top-quark mass is obtained from template fits to the ratio of three-jet to dijet mass. The three-jet mass is calculated from the three jets of a top-quark decay. Using these three jets the dijet mass is obtained from the two jets of the W boson decay. The top-quark mass obtained from this fit is thus less sensitive to the uncertainty in the energy measurement of the jets. A binned likelihood fit yields a top-quark mass of mt = 175.1 ± 1.4 (stat.) ± 1.2 (syst.) GeV.

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The normalized differential cross section for top-quark pair production in association with at least one jet is studied as a function of the inverse of the invariant mass of the tt¯+1-jet system. This distribution can be used for a precise determination of the top-quark mass since gluon radiation depends on the mass of the quarks. The experimental analysis is based on proton--proton collision data collected by the ATLAS detector at the LHC with a centre-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.6 fb−1. The selected events were identified using the lepton+jets top-quark-pair decay channel, where lepton refers to either an electron or a muon. The observed distribution is compared to a theoretical prediction at next-to-leading-order accuracy in quantum chromodynamics using the pole-mass scheme. With this method, the measured value of the top-quark pole mass, mpolet, is: mpolet =173.7 ± 1.5 (stat.) ± 1.4 (syst.) +1.0−0.5 (theory) GeV. This result represents the most precise measurement of the top-quark pole mass to date.

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It was found that the non-perturbative corrections calculated using Pythia with the Perugia 2011 tune did not include the effect of the underlying event. The affected correction factors were recomputed using the Pythia 6.427 generator. These corrections are applied as baseline to the NLO pQCD calculations and thus the central values of the theoretical predictions have changed by a few percent with the new corrections. This has a minor impact on the agreement between the data and the theoretical predictions. Figures 2 and 6 to 13, and all the tables have been updated with the new values. A few sentences in the discussion in sections 5.2 and 9 were altered or removed.

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OBJECTIVE: To detect the prevalence of systemic hypertension in children and to establish the relation between blood pressure levels and sex, age, ethnicity, weight, and height. METHODS: The prevalence of systemic hypertension and its relation to sex, age, ethnicity, weight, and height were studied in 611 students aged 7 to 14 years out of 19.928 students classified according to age, ethnicity, and sex, who underwent anthropometric evaluation and blood pressure measurement. Hypertensive individuals were considered those whose blood pressure level was > the 95th percentile for age and sex, confirmed on 3 examinations. RESULTS: The prevalence of hypertension was 16.6% in the first evaluation, and 4.6% and 2.5% in the subsequent evaluations. The mean blood pressure levels increased with age. Weight was important, not only to determine blood pressure in healthy children, but also to determine systemic hypertension in children, which was not observed with height despite the different studies. The prevalence of systemic hypertension in the different ethnic groups and the mean blood pressure levels according to sex were similar. CONCLUSION: In addition to routine physical examinations, age, weight, and appropriate cuff size should be considered when assessing blood pressure in children to prevent hypertension, morbidity and mortality, and to avoid placing a financial burden on health care providers.

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Como resultado das 40 experiências relatadas neste trabalho, as seguintes conclusões podem ser tiradas: 1) Dos 2 até aos 8 meses de molestia há na bouba uma grande resistência á superinoculação (13 experiências negativas em 15). Nas 2 experiências positivas, foram obtidas lesões atípicas (pianides): a) Tal resistência parece independer da presença de lesões boubaticas cutaneas e se fez sentir mesmo em casos com a lesão inicial exclusiva. b) Dentro desse período de molestia, tal resistência pode desaparecer com o tratamento: 2 doentes tratados aos 6 meses e reinoculados adquiriram bouba em tempo normal. Porém, um caso tratado aos 7 meses e reinoculado, desenvolveu uma pianide. Êste fato parece mostrar que essa resistência depende principalmente da presença da infecção ativa ou latente, raramente traduzindo uma imunidade no verdadeiro sentido do têrmo. c) No caso de emprego de homo-virus, essa resistência prolongou-se até um ano d molestia, havendo apenas um caso duvidoso em 10 inoculações. 2) Do 10º mês ao 4º ano de molestia, em 8 superinoculações observou-se uma resistência parcial que se traduziu de 2 modos, quanto à natureza da lesão atípica que se obteve no ponto inoculado; "lesão frustra papulo-eritematosa" (7 meses); e lesão semelhante ás "pianides" da infecção natural (1 vez), a qual permaneceu localizada sem manifestações metastaticas, até 4 meses de observação. a) Também este estado de resistência parcial, parece independer da presença de lesões boubaticas aparentes. b) Com o tratamento esse estado parece não se modificar: um doente tratado nesse período da molestia, reagiu à inoculação de modo semelhante, embora sem nenhuma manifestação clínica e com a R. Wa. negativa. Inegavelmente, essas "lesões frustras" e também as "pianides" obtidas, representam respostas de organismos que obtiveram vantagens na luta com a doença, possuindo um certo grau de imunidade, que é muitíssimo maior no caso das primeiras. 3) Depois do 5º ano de molestia, a resposta á superinoculação traduziu um estado de maior sensibilidade do organismo infectado. Observou-se no ponto inoculado uma reação precoce papulo-eritemato-ulcerosa, francamente necrotica e destrutiva, ao mesmo tempo que se verificou exacerbação das lesões dos pacientes, com grande infartamento gangliomar satélite. Até 18 meses depois, em um caso, a lesão obtida permaneceu localizada sem manifestações generalizadas. a) O tratamento não modificou tal estado. Doentes tratados ( e parcial ou totalmente curados), reagiram da mesma maneira à reinoculação dentro desse período da molestia. Apenas em um caso de mais de 5 anos (nº 40) não se obteve a lesão ulcero-necrotica. Era o único dos 13 experimentados que não tinha nem tivera lesões ulcero-gomoides destrutivas. por outro lado, 2 pacientes apresentando lesões gomo-ulcerativas, mas tendo menos de 3 anos de molestia, não deram a lesão ulcerativo-necrotica em resposta à superinoculação. (Experiências ns. 38 e 39). Interessante é que esta lesão ulcerativo-necrotica contém treponemas embora raros, e em evolução pode tomar o carater das lesões destrutivas gomo-ulcerativas peculiares ao chamado "período terciario" da doença, com as quais também se assemelha histopatológicamente. Sob o ponto de vista imunológico, esta lesão representa um estado de maior sensibilidade do organismo para o agente infeccioso. 4) Como o tratamento precoce perturba o desenvolvimento da imunidade, sob o ponto de vista epidemiológico, seria aconselhável aguardar o período terminal do chamado secundarismo, isto é da fase de generalização boubatica, para tratar os pacientes em Postos, hospitais ou ambulatórios pois, tais doentes poderiam se reinfestar uma vez retornados ao fóco. Claro que em campanhas terapeuticas profilaticas, as lesões "abertas" primo-secundarias, devem ser rapidamente eliminadas uma vez que são as mais contagiantes, por mais ricas em germes. 5) Existe na framboesia trópica uma verdadeira imunidade além de uma simples resistência á superinoculação devido a presença da infecção ativa ou latente. Com efeito, pacientes tratados em determinado período da molestia e curados clinica e sorologicamente, mostraram resistência parcial á reinoculação, reagindo de modo semelhante a outros do mesmo período de molestia e não tratados. 6) A imunidade na framboesia tropica se manifesta seja como uma resistência á superinoculação ou reinoculação seja como uma modificação da lesão boubatica inicial, seja, finalmente, como uma resistência á generalização da doença. 7) Os resultados das esperiências sugerem que as diferentes manifestações cutaneas da molestia são condicionadas até certo ponto pelo estado imunitario do organismo infectado. 8) Os diferentes gráus de imunidade, encontrados na framboesia trópica, estão até certo ponto relacionados com o tempo de doença. Porém, são atingidos mais ou menos ràpidamente, segundo o organismo infectado e, talvez segundo a virulência do treponema, do mesmo modo como os chamados "secundarismo" e 'terciarismo" da doença.

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Background: Voltage-gated sodium channels (Nav1.x) are important players in chronic pain. A particular interest has grown in Nav1.7, expressed in nociceptors, since mutations in its gene are associated to two inherited pain syndromes or insensitivity to pain. Rufinamide, a drug used to treat refractory epilepsy such as the Lennox-Gastaut syndrome, has been shown to reduce the number of action potentials in cortical neurons without completely blocking Na channels. Aim: The goal of this study was to investigate the effect of rufinamide on Nav1.7 current. Methods and results: Whole-cell patch clamp experiments were performed using HEK293 cells stably expressing Nav1.7. Rufinamide significantly decreased peak sodium current by 28.3, 21.2 and 12.5% at concentrations of 500, 100 and 50μM respectively (precise EC50 could not be calculated since higher rufinamide concentrations could not be achieved in physiological buffer solution). No significant difference on the V1/2 of voltage-dependence of activation was seen; however a shift in the steady-state inactivation curve was observed (-82.6 mV to -88.8 mV and -81.8 to -87.6 mV for 50 and 100 μM rufinamide respectively, p <0.005). Frequency-dependent inhibition of Nav1.7 was also influenced by the drug. One hundred μM rufinamide reduced the peak sodium current (in % of the peak current taken at the first sweep of a train of 50) from 90.8 to 80.8% (5Hz), 88.7 to 71.8% (10 Hz), 69.1 to 49.2% (25 Hz) and 22.3 to 9.8% (50 Hz) (all p <0.05). Onset of fast inactivation was not influenced by the drug since no difference in the time constant of current decay was observed. Conclusion: In the concentration range of plasma level in human treated for epilepsy, 15 μM, rufinamide only minimally blocks Nav1.7. However, it stabilizes the inactivated state and exerts frequencydependent inhibition of Nav1.7. These pharmacological properties may be of use in reducing ectopic discharges as a causal and symptom related contributor of neuropathic pain syndrome.