1,376 research outputs found

    Efeito de diferentes fontes e níveis de nitrogênio na produção de cana-de-açucar.

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    A eficiência da uréia e sulfato de amônio como fontes de nitrônio para as plantas está condicionado às condições climáticas, características do solo e técnicas de aplicação

    Supplementing taurine to plant-based diets improves lipid digestive capacity and amino acid retention of Senegalese sole (Solea senegalensis) juveniles

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    Recent studies reported positive effects of taurine supplementation to plant protein-based diets on fish growth performance and feed conversion ratio but the mechanisms involved remain unclear. The objective of this work was to provide a first insight on the importance of taurine on dietary protein and lipid absorption and utilisation, in Senegalese sole (Solea senegalensis) juveniles fed plant-based diets. Seven practical diets were tested: a fishmeal-based diet (FM) and a plant protein-based formula (PP85) to which taurine was added in graded levels: 0.2% (TAU1), 0.3% (TAU2), 0.4% (TAUS), 0.7% (TAU4) and 1.5% (TAU5). Short-term metabolic trials were performed by tube-feeding the different experimental diets labelled with different tracers: C-14-taurine, C-14-triolein (as tracer of dietary triacylglycerol) and a mixture of C-14-amino acids. Feeding sole juveniles with the PP85 diet affected taurine metabolism, since a higher proportion of dietary taurine was directed to gallbladder and probably used for bile salt synthesis. Consistent with this, fish receiving the plant-based low taurine-content diets (PP85 and TAU1) displayed a poor triacyglycerol digestion capacity. A higher proportion of C-14-amino acids was retained in fish muscle when fed the TAU5 compared to the PP85 diet. These short-term trials suggested that taurine supplementation to a plant-based diet might be beneficial to sole performance by enhancing bile salt synthesis and triacylglycerol digestion as well as muscle amino acid retention. However, this dietary supplementation should be tested in long-term trials to verify the effect on fish growth and to assess the beneficial effects on protein and lipid metabolism suggested here. Statement of relevance in the general field of aquaculture (limited to 60 characters): Adding taurine to a plant-based diet is beneficial for sole (C) 2016 Elsevier B.V. All rights reserved.National Funds through Fundacao para a Ciencia e Tecnologia [PTDC/MAR/117047/2010]Fundacao para a Ciencia e Tecnologia, Portugal [SFRH/BDP/65578/2009]info:eu-repo/semantics/acceptedVersio

    Tunneling catastrophes of the partition function

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    We use path-integrals to derive a general expression for the semiclassical approximation to the partition function of a one-dimensional quantum-mechanical system. Our expression depends solely on ordinary integrals which involve the potential. For high temperatures, the semiclassical expression is dominated by single closed paths. As we lower the temperature, new closed paths may appear, including tunneling paths. The transition from single to multiple-path regime corresponds to well-defined catastrophes. Tunneling sets in whenever they occur. Our formula fully accounts for this feature

    A New Action Principle for Witten's Topological Field Theory

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    In this letter a new gauge invariant, metric independent action is introduced from which Witten's Topological Quantum Field Theory may be obtained after gauge fixing using standard BRST techniques. In our model the BRST algebra of transformations, under which the effective action is invariant, close off-shell in distintion with what occurs in the one proposed by Labastida and Pernici. Our approach provides the geometrical principle for the quantum theory. We also compare our results with an alternative formulation presented by Baulieu and Singer.Comment: 8 pages, SB/F-94-22

    Recomendações técnicas para obtenção de sementes híbridas de coqueiro.

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    Condições ecólogicas requeridas, plantas progenitoras, anões, anão amarelo, anão vermelho, anão verde, gigantes, biologia floral, métodos, coleta e preparo de polen, coleta, secagem e tamisagem, condicionamento, emasculação das plantas, polinização, controles.bitstream/item/43932/1/CPATC-DOCUMENTOS-4-RECOMENDACOES-TECNICAS-PARA-OBTENCAO-DE-SEMENTES-HIBRIDAS-DE-COQUEIRO-FL-13122.pd
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