344 research outputs found

    Canine Antibody Response To Lutzomyia Longipalpis Saliva In Endemic Area Of Visceral Leishmaniasis

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    Introduction: Canine exposure to Lutzomyia longipalpis bites and the potential of Leishmania infantum transmissibility for the vector were evaluated. Methods: Immunoglobulin G (IgG) anti-Lu longipalpis saliva and -L. infantum, and blood parasite load were determined in dogs from endemic areas of visceral leishmaniasis. Results: Blood parasitism was similar between symptomatic and asymptomatic dogs. IgG anti-L. infantum was higher in symptomatic dogs, but IgG anti-Lu. longipalpis saliva was mostly observed in higher titers in asymptomatic dogs, indicating vector preference for feeding on asymptomatic dogs. Conclusions: Our data suggest a pivotal role of asymptomatic dogs in L. infantum transmission in endemic areas. © 2016, Sociedade Brasileira de Medicina Tropical. All rights reserved.49336136

    Supersymmetric Seesaw without Singlet Neutrinos: Neutrino Masses and Lepton-Flavour Violation

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    We consider the supersymmetric seesaw mechanism induced by the exchange of heavy SU(2)_W triplet states, rather than `right-handed' neutrino singlets, to generate neutrino masses. We show that in this scenario the neutrino flavour structure tested at low-energy in the atmospheric and solar neutrino experiments is directly inherited from the neutrino Yukawa couplings to the triplets. This allows us to predict the ratio of the tau --> mu gamma (or tau --> e gamma) and mu --> e gamma decay rates in terms of the low-energy neutrino parameters. Moreover, once the model is embedded in a grand unified model, quark-flavour violation can be linked to lepton-flavour violation.Comment: 26 LaTeX pages, 10 postscript figures, uses epsfig and axodraw. Comments and references adde

    CaracterĂ­sticas clĂ­nico-epidemiolĂłgicas, histomorfolĂłgicas e histoquĂ­micas da esporotricose felina

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    Resumo Esporotricose Ă© uma infecção fĂșngica causada por espĂ©cies do complexo Sporothrix, vista com maior frequĂȘncia em gatos, equinos e cĂŁes. Os principais objetivos deste estudo retrospectivo foram caracterizar os aspectos histomorfolĂłgicos e histoquĂ­micos da esporotricose em 10 gatos, alĂ©m de avaliar os aspectos epidemiolĂłgicos, clĂ­nicos e os achados macroscĂłpicos desses 10 casos, obtidos dos protocolos de biĂłpsias e necropsias dos arquivos do LaboratĂłrio de Patologia VeterinĂĄria da Universidade Federal de Santa Maria. A doença acometeu predominantemente gatos machos, sem raça definida e apresentou-se principalmente na forma cutĂąnea disseminada. As lesĂ”es macroscĂłpicas caracterizaram-se como nĂłdulos cutĂąneos (ulcerados ou nĂŁo) e como massas e placas ulceradas. Na histopatologia observou-se uma relação entre a quantidade de leveduras observada e dois padrĂ”es de resposta inflamatĂłria. O primeiro padrĂŁo caracterizou-se por numerosas leveduras que se encontravam, na sua maioria, no interior de numerosos macrĂłfagos com citoplasma abundante e muitas vezes vacuolizado. Nesse padrĂŁo, a quantidade de neutrĂłfilos variava de leve a moderada. O segundo padrĂŁo caracterizava-se por numerosas cĂ©lulas epitelioides, infiltrado predominantemente acentuado de neutrĂłfilos e a quantidade de leveduras era leve e estas eram observadas geralmente livres no espaço extracelular. As leveduras eram redondas, ovais ou alongadas (em forma de charuto). Foram utilizadas vĂĄrias tĂ©cnicas histoquĂ­micas como a impregnação pela prata de Grocott, ĂĄcido periĂłdico de Schiff e azul Alciano que facilitaram a visualização, caracterização da morfologia e quantificação dos organismos. A coloração de Giemsa permitiu a visualização do agente, porĂ©m nĂŁo permitiu destacĂĄ-los nitidamente de outros elementos intralesionais. Os organismos foram negativos para grĂąnulos de melanina pela coloração de Fontana-Masson em todos os casos. O estudo histomorfolĂłgico e histoquĂ­mico permitiu demonstrar caracterĂ­sticas fĂșngicas determinantes para o estabelecimento do diagnĂłstico de esporotricose atravĂ©s dessa ferramenta diagnĂłstica

    Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

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    Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

    Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

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    A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters

    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
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