265 research outputs found

    EFEITOS DA DISTRIBUIÇÃO DE BACCHARIS DRACUNCULIFOLIA (ASTERACEAE) NA ABUNDÂNCIA E NO PARASITISMO DE GALHAS DE NEOPELMA BACCHARIDIS (HOMOPTERA: PSYLLIDAE)

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    No sistema Baccharis dracunculifolia/ Neopelma baccharidis, os efeitos dos aspectos populacionais da planta hospedeira na abundância das galhas e seus parasitóides ainda são pobremente estudados. Este trabalho teve como objetivo avaliar os efeitos da densidade populacional de B. dracunculifolia no ataque e no parasitismo do galhador N. baccharidis. Neste sentido, quatro populações da planta hospedeira, localizadas na Serra do Cipó, foram escolhidas aleatoriamente. Em cada uma destas populações foram selecionadas, aleatoriamente, 20 plantas, sendo que a densidade das plantas foi estimada contando-se o número vizinhos existentes em um raio de três metros das plantas selecionadas. A abundância de galhas não variou entre as populações que estavam colonizadas pelo herbívoro (F = 1,389, p = 0,260, n = 46). Além disto, a taxa de ataque do galhador também não foi afetada pela densidade da planta hospedeira (r2 = 0,026, p = 0,282, n = 45). O parasitismo das galhas de N. baccharidis não mostrou relação com a densidade de plantas (r2 = 0,094, p = 0,069, n = 36), mas foi afetada pela densidade de galhas por planta (r2 = 0,387, p = 0,001, n = 36). Portando, estes resultados sugerem que outros fatores tais como a dinâmica entre a colonização e a extinção da planta hospedeira e do galhador são mais importantes que a densidade populacional da planta ou o ataque de parasitóides na dinâmica populacional de N. baccaridis

    Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

    Search for supersymmetry in final states with jets, missing transverse momentum and one isolated lepton in sqrt{s} = 7 TeV pp collisions using 1 fb-1 of ATLAS data

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    We present an update of a search for supersymmetry in final states containing jets, missing transverse momentum, and one isolated electron or muon, using 1.04 fb^-1 of proton-proton collision data at sqrt{s} = 7 TeV recorded by the ATLAS experiment at the LHC in the first half of 2011. The analysis is carried out in four distinct signal regions with either three or four jets and variations on the (missing) transverse momentum cuts, resulting in optimized limits for various supersymmetry models. No excess above the standard model background expectation is observed. Limits are set on the visible cross-section of new physics within the kinematic requirements of the search. The results are interpreted as limits on the parameters of the minimal supergravity framework, limits on cross-sections of simplified models with specific squark and gluino decay modes, and limits on parameters of a model with bilinear R-parity violation.Comment: 18 pages plus author list (30 pages total), 9 figures, 4 tables, final version to appear in Physical Review

    Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

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    This paper constructs the reduction of heterotic MM-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe

    Measurement of tau polarization in W->taunu decays with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

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    In this paper, a measurement of tau polarization in W->taunu decays is presented. It is measured from the energies of the decay products in hadronic tau decays with a single final state charged particle. The data, corresponding to an integrated luminosity of 24 pb^-1, were collected by the ATLAS experiment at the Large Hadron Collider in 2010. The measured value of the tau polarization is Ptau = -1.06 +/- 0.04 (stat) + 0.05 (syst) - 0.07 (syst), in agreement with the Standard Model prediction, and is consistent with a physically allowed 95% CL interval [-1,-0.91]. Measurements of tau polarization have not previously been made at hadron colliders.Comment: 10 pages plus author list (25 pages total), 4 figures, 4 tables, revised author list, matches published EPJC versio

    Biodiversity and ecosystem services in the Campo Rupestre: a road map for the sustainability of the hottest Brazilian biodiversity hotspot

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    Global sustainability rests on a myriad of benefits provided by natural ecosystems that support human livelihoods and well-being, from biodiversity persistence to climate regulation. The undeniable importance of conserving tropical forests has drawn most of the conservation spotlight towards it. However, open ecosystems such as the Brazilian Campo Rupestre (rupestrian grassland), have been historically overlooked despite their high diversity and key associated ecosystem services. We highlight major current threats to the persistence of the Campo Rupestre emphasizing its ecological, social, cultural, geo-environmental, and economic importance. We call attention to the importance of the Campo Rupestre as a reservoir of biodiversity and ecosystem services and offer priority actions that resulted from discussions involving scientists, industry representatives, environmental managers, and other members of civil society. Proposed actions include efforts related to ecological restoration, sustainable ecotourism, protection of traditional ecological knowledge, identification of emerging research questions, and development of tailored public policies. Such issues are integrated into a framework that collectively represents a road map to safeguard the Campo Rupestre from further degradation and steer its historical overexploitation towards sustainable management. Safeguarding the future of non-forest biomes like this poses a challenge to current paradigms of nature conservation. By establishing priorities and guidelines, we propose an actionable plan, which we hope can support informed decision-making policy towards a sustainable use of the Campo Rupestre.Long Term Ecological Research PELD-CRSC-17Conselho Nacional de Pesquisas CNPq/MCTIFundação de Amparo à Pesquisa do Estado de São Paulo 2013/50155-0, 2010/51307-0, 2019/07773-
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