190 research outputs found

    Diversity among smallholder farms and households—Consequences for trade-offs, trajectories, targeting and scaling

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    United States Agency for International Developmen

    Integrating local knowledge and remote sensing for eco-type classification map in the Barotse Floodplain, Zambia

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    This eco-type map presents land units with distinct vegetation and exposure to floods (or droughts) in three villages in the Barotseland, Zambia. The knowledge and eco-types descriptions were collected from participatory mapping and focus group discussions with 77 participants from Mapungu, Lealui, and Nalitoya. We used two Landsat 8 Enhanced Thematic Mapper (TM) images taken in March 24th and July 14th, 2014 (path 175, row 71) to calculate water level and vegetation type which are the two main criteria used by Lozi People for differentiating eco-types. We calculated water levels by using the Water Index (WI) and vegetation type by using the Normalized Difference Vegetation Index (NDVI). We also calculated the Normalized Burn Ratio (NBR) index. We excluded burned areas in 2014 and built areas to reduce classification error. Control points include field data from 99 farmers’ fields, 91 plots of 100 m2 and 65 waypoints randomly selected in a 6 km radius around each village. We also used Google Earth Pro to create control points in areas flooded year-round (e.g., deep waters and large canals), patches of forest and built areas. The eco-type map has a classification accuracy of 81% and a pixel resolution of 30 m. The eco-type map provides a useful resource for agriculture and conservation planning at the landscape level in the Barotse Floodplain

    ETHICS OF MANDATORY PREMARITAL HIV TESTING IN AFRICA: THE CASE OF GOMA, DEMOCRATIC REPUBLIC OF CONGO

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    Despite decades of prevention efforts, millions of persons worldwide continue to become infected by the human immunodeficiency virus (HIV) every year. This urgent problem of global epidemic control has recently lead to significant changes in HIV testing policies. Provider-initiated approaches to HIV testing have been embraced by the Centers for Disease Control and Prevention and the World Health Organization, such as those that routinely inform persons that they will be tested for HIV unless they explicitly refuse (‘opt out’). While these policies appear to increase uptake of testing, they raise a number of ethical concerns that have been debated in journals and at international AIDS conferences. However, one special form of ‘provider-initiated’ testing is being practiced and promoted in various parts of the world, and has advocates within international health agencies, but has received little attention in the bioethical literature: mandatory premarital HIV testing. This article analyses some of the key ethical issues related to mandatory premarital HIV testing in resource-poor settings with generalized HIV epidemics. We will first briefly mention some mandatory HIV premarital testing proposals, policies and practices worldwide, and offer a number of conceptual and factual distinctions to help distinguish different types of mandatory testing policies. Using premarital testing in Goma (Democratic Republic of Congo) as a point of departure, we will use influential public health ethics principles to evaluate different forms of mandatory testing. We conclude by making concrete recommendations concerning the place of mandatory premarital testing in the struggle against HIV/AIDS

    The energy spectrum of cosmic rays beyond the turn-down around 10^17 eV as measured with the surface detector of the Pierre Auger Observatory

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    We present a measurement of the cosmic-ray spectrum above 100 PeV using the part of the surface detector of the Pierre Auger Observatory that has a spacing of 750 m. An inflection of the spectrum is observed, confirming the presence of the so-called second-knee feature. The spectrum is then combined with that of the 1500 m array to produce a single measurement of the flux, linking this spectral feature with the three additional breaks at the highest energies. The combined spectrum, with an energy scale set calorimetrically via fluorescence telescopes and using a single detector type, results in the most statistically and systematically precise measurement of spectral breaks yet obtained. These measurements are critical for furthering our understanding of the highest energy cosmic rays

    Measurement of ϒ production in pp collisions at √s = 2.76 TeV

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    The production of ϒ(1S), ϒ(2S) and ϒ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb−1 collected in proton–proton collisions at a centre-of-mass energy of √s = 2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the ϒ transverse momentum and rapidity, over the ranges pT < 15 GeV/c and 2.0 < y < 4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be σ (pp → ϒ(1S)X) × B ϒ(1S)→Ό+Ό− = 1.111 ± 0.043 ± 0.044 nb, σ (pp → ϒ(2S)X) × B ϒ(2S)→Ό+Ό− = 0.264 ± 0.023 ± 0.011 nb, σ (pp → ϒ(3S)X) × B ϒ(3S)→Ό+Ό− = 0.159 ± 0.020 ± 0.007 nb, where the first uncertainty is statistical and the second systematic

    Study of the doubly charmed tetraquark T+cc

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    Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed
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