261 research outputs found

    Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.

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    The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by the altitude and position of the area relative to the sun

    Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources

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    We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > 10310^3 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples

    Search for the doubly heavy baryon Ξbc+\it{\Xi}_{bc}^{+} decaying to J/ψΞc+J/\it{\psi} \it{\Xi}_{c}^{+}

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    A first search for the Ξbc+J/ψΞc+\it{\Xi}_{bc}^{+}\to J/\it{\psi}\it{\Xi}_{c}^{+} decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9fb19\,\mathrm{fb}^{-1} recorded at centre-of-mass energies of 7, 8, and 13TeV13\mathrm{\,Te\kern -0.1em V}. Two peaking structures are seen with a local (global) significance of 4.3(2.8)4.3\,(2.8) and 4.1(2.4)4.1\,(2.4) standard deviations at masses of 6571MeV ⁣/c26571\,\mathrm{Me\kern -0.1em V\!/}c^2 and 6694MeV ⁣/c26694\,\mathrm{Me\kern -0.1em V\!/}c^2, respectively. Upper limits are set on the Ξbc+\it{\Xi}_{bc}^{+} baryon production cross-section times the branching fraction relative to that of the Bc+J/ψDs+B_{c}^{+}\to J/\it{\psi} D_{s}^{+} decay at centre-of-mass energies of 8 and 13TeV13\mathrm{\,Te\kern -0.1em V}, in the Ξbc+\it{\Xi}_{bc}^{+} and in the Bc+B_{c}^{+} rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20GeV ⁣/c20\,\mathrm{Ge\kern -0.1em V\!/}c, respectively. Upper limits are presented as a function of the Ξbc+\it{\Xi}_{bc}^{+} mass and lifetime.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-005.html (LHCb public pages
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