293 research outputs found

    Uso da Espectroscopia Raman e FT-IR na caracterização do biocarvão em Latossolo Amarelo da Amazônia Central

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    The Amazonian Latosols are acidic soils shows low activity in clay minerals. However, it is also found anthropogenic soils known as Amazonian Dark Earth (EAD) that provides a potential to develop a sustainable system in agriculture. The majority of TPI soils show fragments of black carbon stemming from an anthropic activity. The presence of these fragments endows the improvements in the physic and chemical characteristics of the soil. In order to reproduce some characteristics of these anthropogenic soils, it is proposed to apply biochar (BC) in a dystrophic Yellow Oxisol in increasing doses from 0; 40; 80 and 120 t.ha-1. The use of Spectroscopy FT-IR and Raman tools and technics can elucidate on the nature of the pyrolised biomass and likewise interfere on the fertility of the soil. Furthermore, it could clarify how the BC contributes to the increase of cation exchange capacity (CEC), the elucidation of its chemical characteristics and how it can act in the development of a sustainable agriculture model for the humid tropics. It was possible to observe that he FT-IR spectra were similar between the treatments and that the BC exhibits similar crystallinity to the carbons of Amazonian Dark Earth

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    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
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