56 research outputs found

    Physiological quality, content and activity of antioxidants in soybean seeds artificially aged.

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    ABSTRACT - The objective of this study was to evaluate physiological quality, content, and activity of antioxidants, in soybean seeds subjected to accelerated aging during different periods. Seeds of cultivars BRS 258, BRS 262 and BRS 268, subjected to accelerated aging during 12, 24, 36 and 48 hours and non-aged seeds were used. After each aging period, the seed were evaluated by tests of: germination; first count and tetrazolium. The total of phenolic compounds, total flavonoides, total of isoflavones, and activity for eliminating ABTS°+ radicals were quantified. There were differences among cultivars according to vigor and viability only after seeds were aged. Cultivars BRS 158 and BRS 268 have shown better seed physiological quality in each aging period; however, not presenting higher amounts of isoflavones and efficiency in removing free radicals. For all cultivars, the values for total of phenolic compounds, as well as total of flavonoids have shown quadratic positive behavior; the values for isoflavones remained constant and the vigor and viability showed contrary trend to activity of antioxidant agents. RESUMO: Qualidade fisiolĂłgica, conteĂșdo e atividade de antioxidantes presentes em sementes de soja envelhecidas artificialmente. O objetivo deste trabalho foi avaliar a qualidade fisiolĂłgica, o conteĂșdo e a atividade de agentes antioxidantes presentes em sementes de soja envelhecidas durante diferentes perĂ­odos. Foram utilizadas sementes das cultivares BRS 258, BRS 262 e BRS 268, envelhecidas durante 12, 24, 36 e 48 h e sementes nĂŁo envelhecidas. ApĂłs cada perĂ­odo de envelhecimento, as sementes foram avaliadas pelo testes de: germinação; primeira contagem e tetrazĂłlio. Foram quantificados: compostos fenĂłlicos totais; flavonĂłides totais; total de isoflavonas e atividade eliminadora do radical ABTS°+. Houve diferença entre as cultivares em relação ao vigor e viabilidade somente quando foram envelhecidas. BRS 158 e BRS 268 apresentaram melhor qualidade fisiolĂłgica de sementes em cada perĂ­odo de envelhecimento, porĂ©m, nĂŁo apresentaram maior quantidade de isoflavonas e eficiĂȘncia no sequestro dos radicais livres. Para todas as cultivares, os valores de compostos fenĂłlicos totais, assim como os flavonĂłides totais, apresentaram comportamento quadrĂĄtico positivo; os valores das isoflavonas permaneceram constantes e o vigor e a viabilidade apresentaram tendĂȘncia contrĂĄria Ă  atividade dos agentes antioxidantes

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

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    Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≄6 to ≄9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV

    Length Sensing and Control in the Virgo Gravitational Wave Interferometer

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    The gravitational wave detector Virgo is presently being commissioned. A significant part of last year was spent in setting up the cavity length control system. This work was carried out with steps of increasing complexity: locking a simple Fabry-Perot cavity, then a Michelson interferometer with Fabry-Perot cavities in both arms, and finally recycling the light beam into the interferometer. The applied strategy and the main results obtained are describe

    The status of VIRGO

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    In this paper the main characteristics of the interferometric gravitational waves detector Virgo are presented as well as its present status and perspectives

    Interferometric detectors of gravitational waves on Earth: the next generations

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    International audienceThe interferometric detectors of gravitational waves of first generation are now taking data. A first detection might be possible with these instruments, but more sensitive detectors will be needed to start the gravitational wave astronomy. The interferometers of second generation will improve the sensitivity by a factor ten, allowing to explore a universe volume 1000 times larger. The technology is almost ready and the construction will start at the beginning of next decade. The community of the physicists involved in the field has also started to make plans for third generation detectors, for which a long term technology development will be required. The plans for the upgrades of the existing detectors and the scenario for the evolution of the field will be reviewed in this paper

    LIGO and VIRGO: large interferometers searching for gravitational waves

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    International audienceThe largest interferometric detectors for gravitational waves, LIGO and Virgo, have reached (or are close to) the design sensitivity and have started taking science data. The operation of such detectors is reviewed and the expected sources and detection rates are discussed. LIGO and Virgo might make the first detection, but more advanced detectors will be needed to truly open the field of gravitational wave astronomy: the current ideas and plans for the upgrades of the existing interferometers are presented

    Data Acquisition System of the Virgo Gravitational Waves Interferometric Detector

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    International audienceVirgo is an experiment aiming at the detection of gravitational waves emitted by astrophysical sources. Its detector, based on a 3km arms interferometer, is a complex setup which requires several digital control loops running up to 10kHz, an accurate and reliable central timing system and an efficient data acquisition, all of them being distributed over 3km. We overview here the main hardware and software components developed for the data acquisition system (DAQ) and its current architecture. Then, we briefly discuss its connections with interferometer's controls, especially through the automation of the interferometer's startup procedure. Then, we describe the tools used to monitor the DAQ and the performances we measured with them. Finally, are described also the tools developped for the online detector monitoring, mandatory complement of the DAQ for the commissioning of the Virgo detector
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