341 research outputs found

    Pesca artesanal do camarão sete-barbas: uma caracterização sócio-econômica na Penha, SC

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    Marine resources exploration along Santa Catarina coast plays an important role in the socioeconomic and cultural context. Considering this information, the elaboration of a management plan for fishery resources should consider beyond the biological, physical and chemical components, the socioeconomic dimension. This work aimed to characterize the socioeconomic profile of the fishermen of sea-bob-shrimp at Penha (Santa Catarina State). To accomplish this characterization, 55 local fishermen were interviewed, regarding scholar instruction of fisherman and their family, data on fishery activity, destination and commercialization of the shrimp and by-catch, and also the gear utilized in the fishery. Results showed an age composition of fishermen predominantly among 40 and 50 years old, confirming that the activity is performed mainly by the elders of the community, which on the other hand, cannot keep their family only with the fishery profits. Such situation is driving the activity to a decline, in a way that fishermen are being obligated to accept informal jobs, putting in risk their survivorship and a rich Azorean culture.Marine resources exploration along Santa Catarina coast plays an important role in the socioeconomic and cultural context. Considering this information, the elaboration of a management plan for fishery resources should consider beyond the biological, physical and chemical components, the socioeconomic dimension. This work aimed to characterize the socioeconomic profile of the fishermen of sea-bob-shrimp at Penha (Santa Catarina State). To accomplish this characterization, 55 local fishermen were interviewed, regarding scholar instruction of fisherman and their family, data on fishery activity, destination and commercialization of the shrimp and by-catch, and also the gear utilized in the fishery. Results showed an age composition of fishermen predominantly among 40 and 50 years old, confirming that the activity is performed mainly by the elders of the community, which on the other hand, cannot keep their family only with the fishery profits. Such situation is driving the activity to a decline, in a way that fishermen are being obligated to accept informal jobs, putting in risk their survivorship and a rich Azorean culture

    Determination of the high-pressure crystal structure of BaWO4 and PbWO4

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    We report the results of both angle-dispersive x-ray diffraction and x-ray absorption near-edge structure studies in BaWO4 and PbWO4 at pressures of up to 56 GPa and 24 GPa, respectively. BaWO4 is found to undergo a pressure-driven phase transition at 7.1 GPa from the tetragonal scheelite structure (which is stable under normal conditions) to the monoclinic fergusonite structure whereas the same transition takes place in PbWO4 at 9 GPa. We observe a second transition to another monoclinic structure which we identify as that of the isostructural phases BaWO4-II and PbWO4-III (space group P21/n). We have also performed ab initio total energy calculations which support the stability of this structure at high pressures in both compounds. The theoretical calculations further find that upon increase of pressure the scheelite phases become locally unstable and transform displacively into the fergusonite structure. The fergusonite structure is however metastable and can only occur if the transition to the P21/n phases were kinetically inhibited. Our experiments in BaWO4 indicate that it becomes amorphous beyond 47 GPa.Comment: 46 pages, 11 figures, 3 table

    Resposta de cultivares de batata a níveis crescentes de NPK.

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    Made available in DSpace on 2018-02-05T23:36:03Z (GMT). No. of bitstreams: 1 ArionePereiraRespostadecultivaresdebatata.pdf: 359213 bytes, checksum: beab41c27497ae35cd61908f3db72e4c (MD5) Previous issue date: 2018-02-05bitstream/item/172171/1/Arione-Pereira-Resposta-de-cultivares-de-batata.pd

    Preparation of Single-Phase Films of CH3NH3Pb(I1-xBrx)3 with Sharp Optical Band Edges.

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    Organometallic lead-halide perovskite-based solar cells now approach 18% efficiency. Introducing a mixture of bromide and iodide in the halide composition allows tuning of the optical bandgap. We prepare mixed bromide-iodide lead perovskite films CH3NH3Pb(I1-xBrx)3 (0 ≤ x ≤ 1) by spin-coating from solution and obtain films with monotonically varying bandgaps across the full composition range. Photothermal deflection spectroscopy, photoluminescence, and X-ray diffraction show that following suitable fabrication protocols these mixed lead-halide perovskite films form a single phase. The optical absorption edge of the pure triiodide and tribromide perovskites is sharp with Urbach energies of 15 and 23 meV, respectively, and reaches a maximum of 90 meV for CH3NH3PbI1.2Br1.8. We demonstrate a bromide-iodide lead perovskite film (CH3NH3PbI1.2Br1.8) with an optical bandgap of 1.94 eV, which is optimal for tandem cells of these materials with crystalline silicon devices.We acknowledge funding from the Engineering and Physical Sciences Research Council (EPSRC) and the Winton Programme (Cambridge) for the Physics of Sustainability. THT acknowledges funding from Cambridge Australia Scholarships and the Cambridge Commonwealth Trust. D.C. acknowledges support from St. John's College Cambridge and the Winton Programme (Cambridge) for the Physics of Sustainability.This is the final published version. It's also available at: http://pubs.acs.org/doi/abs/10.1021/jz501332v
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