952 research outputs found

    Occurrence of viruses and stunting diseases and estimative of yield losses by mollicutes in corn in ParanĂĄ State, Brazil

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    O objetivo deste trabalho foi avaliar a incidĂȘncia de viroses e enfezamentos e estimar as perdas causadas por enfezamentos na cultura do milho safrinha. Os diagnĂłsticos baseados em sintomas foram confirmados por PCR ou RTPCR. Em todas as lavouras, foram identificadas plantas com sintomas de enfezamentos, em incidĂȘncia de 6,2% a 49,9% (mĂ©dia de 20,7%). Na identificação de insetos vetores desses patĂłgenos, a cigarrinha Dalbulus maidis foi detectada em 20 lavouras das 24 amostradas, constituindo 66,6% do total de espĂ©cimens de cigarrinhas coletadas. A perda potencial causada pelos enfezamentos no perĂ­odo foi estimada em cerca de 16,5 milhĂ”es de dĂłlares. A ocorrĂȘncia de plantas com sintomas de "Maize rayado fino virus" e "Maize dwarf mosaic virus" foi baixa e o diagnĂłstico confirmado por RTPCR. A anĂĄlise de 441 amostras suspeitas de infecção por "Mal de RĂ­o Cuarto virus", por DASELISA, mostrou ausĂȘncia desse vĂ­rus. Resultados de PCR indicaram a presença de um possĂ­vel fitoplasma distinto de "Maize bushy stunt phytoplasma" em duas plantas apresentando nanismo acentuado, folhas estreitas, enrijecidas, com deformaçÔes, e grĂŁos na inflorescĂȘncia, havendo necessidade de mais estudos para a confirmação da identidade desse possĂ­vel novo fitoplasma.The objective of this work was to evaluate the occurence and yield losses by corn stunting diseases and maize viruses in "safrinha" season. Disease diagnostics based on plant symptoms were confirmed by PCR or RTPCR assays. Insect samples were collected in 24 fields for identification of vectors of the pathogens. Corn stunting diseases symptoms were observed in all crops evaluated, with incidence levels ranging from 6.2% to 49.9% (average 20.7%) and the presence of the leafhopper Dalbulus maidis, was detected in 20 of the 24 areas evaluated. This insect species was prevalent, representing 66,6% of total leafhoppers specimens collected. The potential yield losses caused by mollicutes was estimated around US$ 16.5 million. Few plants showing Maize rayado fino virus and Maize dwarf mosaic virus symptoms were found and virus infection was confirmed by RTPCR. Mal de RĂ­o Cuarto virus was not detected in all 441 plants analyzed by DASELISA. Results of PCR assays indicated the presence of a possible phytoplasma different from maize bushy stunt phytoplasma in two stunting maize plants showing leaves distortions and grain in the inflorescence. However, new studies should be done to confirm the identity of this possible new phytoplasma

    Individual performance: the influence of the values, the type of remuneration and the goals on individual performance / Desempenho individual: a influĂȘncia dos valores, do tipo de remuneração e das metas

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    Este trabalho teve como objetivo analisar os efeitos dos valores pessoais, o tipo de remuneração e metas sobre o desempenho dos indivĂ­duos, por meio de um experimento em laboratĂłrio utilizando a metodologia de anagramas. Para a pesquisa, foi realizado um experimento com alunos e funcionĂĄrios de uma instituição de ensino superior de Minas Gerais. A anĂĄlise dos dados foi realizada usando um modelo log-linear marginal de Liang e Zeger (1986) com o auxĂ­lio do software R. Os resultados sinalizaram que o tipo de remuneração e o uso de metas nĂŁo afetaram o desempenho dos indivĂ­duos, mas os indivĂ­duos que optaram pela remuneração variĂĄvel tiveram uma renda 29% maior do que os indivĂ­duos que optaram pela remuneração fixa. IndivĂ­duos com maior grau de benevolĂȘncia apresentaram desempenho 14% pior. Os indivĂ­duos do sexo masculino tiveram desempenho 26% superior ao das mulheres. Os alunos tiveram 18% mais desempenho do que os funcionĂĄrios. IndivĂ­duos que jĂĄ haviam realizado atividades com anagramas tiveram desempenho 19% superior e a experiĂȘncia adquirida pelos indivĂ­duos durante o experimento foi fundamental para aquela parte deles que mudou sua preferĂȘncia pelo tipo de remuneração

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

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    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  Όb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∌0) correlation that grows rapidly with increasing ÎŁETPb. A long-range “away-side” (Δϕ∌π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ÎŁETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁥2Δϕ modulation for all ÎŁETPb ranges and particle pT

    Search for the neutral Higgs bosons of the minimal supersymmetric standard model in pp collisions at root s=7 TeV with the ATLAS detector

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    A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb-1 to 4.8 fb-1. Higgs boson decays into oppositely-charged muon or τ lepton pairs are considered for final states requiring either the presence or absence of b-jets. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived. The exclusion limits are for the production cross-section of a generic neutral Higgs boson, φ, as a function of the Higgs boson mass and for h/A/H production in the MSSM as a function of the parameters mA and tan ÎČ in the mhmax scenario for mA in the range of 90GeV to 500 GeV. Copyright CERN

    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
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