Kit diagnóstico para a maior ameaça bananicultura mundial.

A raça 4 tropical (TR4) de Fusarium oxysporum f. sp. cubense (Foc), praga quarentenária A1 para a África e as Américas é atualmente a maior ameaça da bananicultura mundial. Na ausência de variedades resistentes e considerando o tempo necessário para gerar novas cultivares, as medidas de controle mais eficientes são evitar sua entrada e detectar e erradicar focos de infecção. Para tal, um método de diagnóstico rápido, confiável e altamente específico é essencial. Embora um método fora anteriormente proposto (Lin et al. 2008), o mesmo não mostrou especificidade para TR4 (Dita et al. 2010).Disponível em: Acesso em: 21 fev. 2011

Seed degeneration of banana planting materials: strategies for improved farmer access to healthy seed

Vegetatively propagated crops suffer from yield loss and reduced stand density and longevity caused by the build‐up of certain pests and pathogens between successive plantings via infected planting material. Here, six seedborne phytosanitary problems of banana are reviewed to evaluate whether a seed degeneration framework is a useful tool to identify approaches to achieve healthier planting materials. Phytoparasitic nematodes and weevils generate gradual declines in yields and in sucker health. Fusarium wilt and banana bunchy top virus cause progressive mat collapse across the field. Symptomless suckers from any mat in infested fields represent a risk of transmitting the disease to a new field. Xanthomonas and ralstonia wilts, due to incomplete systemicity, are intermediate in their threat to yield loss and frequency of transmission in suckers. Losses to banana streak virus are triggered by abiotic stress, although sucker transmission of episomal banana streak virus also contributes. A qualitative equation described here for seed degeneration covers a cycle beginning with the quality and risk factors of the planting material used to plant a new field and ends with the quality and risk factors of the suckers extracted from the field to plant a new field. This review of five planting material multiplication methods commonly used in banana contrasts their differing usefulness to address seed degeneration in the small farm context. It is proposed that initiatives to offset banana seed degeneration should integrate the role of off‐farm actors into decentralized initiatives rather than attempt to duplicate national seed certification frameworks from other true seed or vegetatively propagated crops

Possible Discovery Channel for New Charged Leptons at the LHC

We propose a channel for the possible discovery of new charged leptons at the Large Hadron Collider. The proposed final state contains three same-sign leptons, making this new channel practically back- groundless. The method is illustrated for two different cases: the four-family Standard Model and the Grand Unified Theory based on the E6 gauge group. An example study taking 250 GeV as the charged lepton mass shows that in both models, about 8 signal events can be expected at 14 TeV center-of-mass energy with 1 fb^-1 of integrated luminosity. Although the event yield might not be sufficient for detailed measurements of the charged lepton properties, it would be sufficient to claim discovery through a counting experiment.Comment: 8 pages, 4 figures. v2 update includes an estimate of the backgrounds, consideration of the EW oblique parameters, and minor improvements. v3 update includes detector acceptance and ttbar backgroun

Kit diagnóstico para a raça 4 tropical de Fusarium oxysporum f. sp. cubense, agente causal do mal-do-Panamá da bananeira.

A raça 4 tropical (RT4) de Fusarium oxysporum f. sp. cubense (Foc), praga quarentenária A1 para África e América é atualmente a maior ameaça da bananicultura mundial. Na ausência de variedades resistentes e considerando o tempo necessário para gerar novas cultivares, as medidas de controle mais eficientes são evitar sua entrada e detectar e erradicar focos de infecção. Para tal, um método de diagnóstico rápido, confiável e altamente específico é essencial.Disponível em: Acesso em: 21 fev. 2011

J/psi azimuthal anisotropy relative to the reaction plane in Pb-Pb collisions at 158 GeV per nucleon

The J/$\psi$ azimuthal distribution relative to the reaction plane has been measured by the NA50 experiment in Pb-Pb collisions at 158 GeV/nucleon. Various physical mechanisms related to charmonium dissociation in the medium created in the heavy ion collision are expected to introduce an anisotropy in the azimuthal distribution of the observed J/$\psi$ mesons at SPS energies. Hence, the measurement of J/$\psi$ elliptic anisotropy, quantified by the Fourier coefficient v$_2$ of the J/$\psi$ azimuthal distribution relative to the reaction plane, is an important tool to constrain theoretical models aimed at explaining the anomalous J/$\psi$ suppression observed in Pb-Pb collisions. We present the measured J/$\psi$ yields in different bins of azimuthal angle relative to the reaction plane, as well as the resulting values of the Fourier coefficient v$_{2}$ as a function of the collision centrality and of the J/$\psi$ transverse momentum. The reaction plane has been estimated from the azimuthal distribution of the neutral transverse energy detected in an electromagnetic calorimeter. The analysis has been performed on a data sample of about 100 000 events, distributed in five centrality or p$_{\rm T}$ sub-samples. The extracted v$_{2}$ values are significantly larger than zero for non-central collisions and are seen to increase with p$_{\rm T}$.Comment: proceedings of HP08 conference corrected a typo in one equatio

A new measurement of J/psi suppression in Pb-Pb collisions at 158 GeV per nucleon

We present a new measurement of J/psi production in Pb-Pb collisions at 158 GeV/nucleon, from the data sample collected in year 2000 by the NA50 Collaboration, under improved experimental conditions with respect to previous years. With the target system placed in vacuum, the setup was better adapted to study, in particular, the most peripheral nuclear collisions with unprecedented accuracy. The analysis of this data sample shows that the (J/psi)/Drell-Yan cross-sections ratio measured in the most peripheral Pb-Pb interactions is in good agreement with the nuclear absorption pattern extrapolated from the studies of proton-nucleus collisions. Furthermore, this new measurement confirms our previous observation that the (J/psi)/Drell-Yan cross-sections ratio departs from the normal nuclear absorption pattern for semi-central Pb-Pb collisions and that this ratio persistently decreases up to the most central collisions.Comment: 19 pages, 10 figures. Submitted to Eur. Phys. J.

Genetic transformation of Fusarium oxysporum f. sp. cubense.

Edição dos Resumos do 42° Congresso Brasileiro de Fitopatologia, Rio de Janeiro, ago. 2009

The dependence of the anomalous J/psi suppression on the number of participant nucleons

The observation of an anomalous J/psi suppression in Pb-Pb collisions by the NA50 Collaboration can be considered as the most striking indication for the deconfinement of quarks and gluons at SPS energies. In this Letter, we determine the J/psi suppression pattern as a function of the forward hadronic energy E-ZDC measured in a Zero Degree Calorimeter (ZDC). The direct connection between EZDC and the geometry of the collision allows us to calculate, within a Glauber approach, the precise relation between the number of participant nucleons N-part and E-ZDC. Then, we check if the experimental data can be better explained by a sudden or a smooth onset of the anomalous J/psi suppression as a function of the number of participants. (C) 2001 Elsevier Science B.V. All rights reserved.info:eu-repo/semantics/publishedVersio

Bottomonium and Drell-Yan production in p-A collisions at 450 GeV

The NA50 Collaboration has measured heavy-quarkonium production in p-A collisions at 450 GeV incident energy (sqrt(s) = 29.1 GeV). We report here results on the production of the Upsilon states and of high-mass Drell-Yan muon pairs (m > 6 GeV). The cross-section at midrapidity and the A-dependence of the measured yields are determined and compared with the results of other fixed-target experiments and with the available theoretical estimates. Finally, we also address some issues concerning the transverse momentum distributions of the measured dimuons.Comment: 18 pages, 9 figures, to be published in Phys. Lett.

Centrality Behaviour of J/ψ\psi Production in Na50

The J/$\psi$ production in 158 A GeV Pb-Pb interactions is studied, in the dimuon decay channel, as a function of centrality, as measured with the electromagnetic or with the very forward calorimeters. After a first sharp variation at mid centrality, both patterns continue to fall down and exhibit a curvature change at high centrality values. This trend excludes any conventional hadronic model and is in agreement with a deconfined quark-gluon phase scenario. We report also preliminary results on the measured charged multiplicity, as given by a dedicated detector.Comment: 5 pages, 7 figures (in eps) talk given at XXXI International Symposium on Multiparticle Dynamics, Sep. 1-7, 2001, Datong China URL http://ismd31.ccnu.edu.cn