1,100 research outputs found

    Ictiofauna Da Cachoeira De São Roberto E Peixes Do Baixo Rio Preto, Bacia Do Alto Rio Paraná, Brasil

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    Rheophilic environments typically houses fish species with specific ecological requirements. Thus, the suppression of these environments can lead to damaging impacts to local and regional fauna. In this work the ichthyofauna of the “Cachoeira de São Roberto” was inventoried, with a historical review of fish collected in the lower Preto River basin. The sampling sites included two reaches (named R1 and R2): R1 in the “Cachoeira de São Roberto” and R2 refers to two km upstream. The fishes were sampled bimonthly during one year (April 2013 to February 2014) using small and dip nets. Voucher specimens were catalogued in the Fish Collection of “Departamento de Zoologia e Botânica do Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista ‘Júlio de Mesquita Filho’, câmpus de São José do Rio Preto, SPˮ (DZSJRP). Historical records from lower Preto River basin were composed by fish species sampled downstream of spillway of the dam in the municipality of São José do Rio Preto, SP, using the database of fish collection of DZSJRP. The ichthyofauna of the sampled reaches was composed by 53 species, distributed in 16 families and seven orders. The greatest richness was found in the upstream site (R2) with the presence of Aphyocheirodon hemigrammus and Myleus tiete, two Brazilian threatened fish species. Chao index suggested the occurrence of 64 species for the inventoried reaches. Considering all portion of lower Preto River basin, including historical records, 69 species were found, four of these species have not described yet. The present study highlights the importance of inventories in rheophilic environments, which usually includes sensitive, threatened, and species with restricted distribution. Besides that, inventories can provide technical data to support decisions about potential environmental impacts helping with the management and conservation of fish fauna. © 2017, Universidade Estadual de Campinas UNICAMP. All rights reserved.17

    Propolis Extract In Postharvest Conservation Of Solo Papaya Cv. 'golden'

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    The high perishability of papaya (Carica papaya L.) reduces the lifespan as well as limits marketing. Coating fruit is an alternative process to aid food preservation. The objective of this study was to evaluate the effects of propolis extract coating on physicochemical characteristics of papaya stored at room temperature. Solo papayas cv. 'Golden' were randomly divided into five postharvest treatments: three forms of dip-coating (70% alcohol, hydroalcoholic extract of propolis at 2.5%, and hydroalcoholic extract of propolis at 5%) and two controls (one uncoated and one with refrigerated uncoated fruit). Each four days, weight loss, fruit firmness, soluble solids (SS), titratable acidity (TA), SS/ TA ratio, and hydrogen potential (pH) were evaluated throughout 12 days of storage. A sensory analysis was performed on the fourth day of storage, being appraised by untrained tasters through acceptance testing. Refrigerated, 2.5% propolis, and 5% propolis treatments promoted the lowest weight losses. Flesh firmness of 5% propolis treatment was superior to that of control, alcohol, and 2.5% propolis treatments. Moreover, 5% propolis treatment achieved a great SS, differing only from alcohol treatment. Both TA and SS/TA had no variations among treatments, but along storage time. Flesh pH of refrigerated papaya showed significant differences in relation to other treatments. Also, refrigerated fruit presented chilling injury symptoms. Propolis-coated papaya showed sensory acceptability similar to those of the other treatments on the 4th day of storage. Therefore, propolis coating renders Solo papaya cv. 'Golden' a promising alternative to control fruit weight losses and firmness.3764039405

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Inclusive search for same-sign dilepton signatures in pp collisions at root s=7 TeV with the ATLAS detector

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    An inclusive search is presented for new physics in events with two isolated leptons (e or mu) having the same electric charge. The data are selected from events collected from p p collisions at root s = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb(-1). The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, e mu and mu mu channels. Four models predicting same-sign dilepton signals are constrained: two descriptions of Majorana neutrinos, a cascade topology similar to supersymmetry or universal extra dimensions, and fourth generation d-type quarks. Assuming a new physics scale of 1 TeV, Majorana neutrinos produced by an effective operator V with masses below 460 GeV are excluded at 95% confidence level. A lower limit of 290 GeV is set at 95% confidence level on the mass of fourth generation d-type quarks

    Standalone vertex finding 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

    Measurement of inclusive two-particle angular correlations in pp collisions with the ATLAS detector at the LHC

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    We present a measurement of two-particle angular correlations in proton- proton collisions at s√=900 GeV and 7 TeV. The collision events were collected during 2009 and 2010 with the ATLAS detector at the Large Hadron Collider using a single-arm minimum bias trigger. Correlations are measured for charged particles produced in the kinematic range of transverse momentum p T  > 100 MeV and pseudorapidity |η| < 2.5. A complex structure in pseudorapidity and azimuth is observed at both collision energies. Results are compared to pythia 8 and herwig++ as well as to the AMBT2B, DW and Perugia 2011 tunes of pythia 6. The data are not satisfactorily described by any of these models

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