2,767 research outputs found

    Assessment of diversity of native species produced in forest nurseries of Rio de Janeiro State

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    AbstractThe objective of this paper was to evaluate the diversity of native species produced by nurseries in the State of Rio de Janeiro. The diagnostic and survey were conducted during the months of February, March and April of the year 2010, the research included all nurseries that produced seedlings of Atlantic Forest species. The fieldwork consisted of visits to the 70 surveyed nurseries, in which a list of the species produced in the nursery was requested and the seedling production manager was interviewed, filling in a questionnaire covering various topics related to seedlings production. We observed 277 forest species native from the Atlantic Forest produced in the nurseries. In average, the nurseries produce 56 different native species. The total diversity of native species produced in the State of Rio de Janeiro is low, as well as the mean diversity, since more than half of the nurseries work with a list of 50 or fewer species, what is insufficient considering the diversity of forest species that occur in the different vegetation types of the state.Keywords: Forest seedlings; forest restoration; Atlantic Forest.O objetivo deste trabalho foi avaliar a diversidade de espécies florestais nativas produzidas nos viveiros do estado do Rio de Janeiro. O levantamento e diagnóstico foram realizados durante os meses de fevereiro, março e abril de 2010, sendo incluídos os viveiros que produziam mudas de espécies florestais da Mata Atlântica. O trabalho de campo consistiu em visitas a 70 viveiros florestais, nos quais foi requerida a lista das espécies produzidas e realizada entrevista com o responsável, sendo preenchido um questionário englobando diversos temas relacionados à produção de mudas. Foram observadas 277 espécies florestais nativas da Mata Atlântica sendo produzidas nos viveiros, que, em média, trabalham com 56 espécies nativas. A diversidade total de espécies florestais da Mata Atlântica produzidas nos viveiros do Estado do Rio de Janeiro é baixa, assim como a diversidade média, já que mais da metade dos viveiros trabalha com uma listagem de 50 ou menos espécies, número insuficiente considerando a diversidade de espécies florestais presentes nas diferentes formações vegetais do estado.Palavras-chave: Mudas florestais; restauração florestal; Mata Atlântica. AbstractAssessment of diversity of native species produced in forest nurseries of Rio de Janeiro State. The objective of this paper was to evaluate the diversity of native species produced by nurseries in the State of Rio de Janeiro. The diagnostic and survey were conducted during the months of February, March and April of the year 2010, the research included all nurseries that produced seedlings of Atlantic Forest species. The fieldwork consisted of visits to the 70 surveyed nurseries, in which a list of the species produced in the nursery was requested and the seedling production manager was interviewed, filling in a questionnaire covering various topics related to seedlings production. We observed 277 forest species native from the Atlantic Forest produced in the nurseries. In average, the nurseries produce 56 different native species. The total diversity of native species produced in the State of Rio de Janeiro is low, as well as the mean diversity, since more than half of the nurseries work with a list of 50 or fewer species, what is insufficient considering the diversity of forest species that occur in the different vegetation types of the state.Keywords: Forest seedlings; forest restoration; Atlantic Forest

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

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    A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino
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