4,697 research outputs found

    Barbosa et al. Reply to ``Comment on 'Secure Communication using mesoscopic coherent states', Barbosa et al, Phys Rev Lett 90, 227901", Yuan and Shields, Phys. Rev. Lett. 94, 048901(2005)

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    Yuan and Shields claim that our data-encryption protocol is entirely equivalent to a classical stream cipher utilizing no quantum phenomena. Their claim is, indeed, false. Yuan and Shields also claim that schemes similar to the one presented in Phys. Rev. Lett. 90, 227901 are not suitable for key generation. This claim is also refuted. In any event, we welcome the opportunity to clarify the situation for a wider audience.Comment: This is the co-published Reply to the Comment made by Z.L. Yuan and A.J. Shields published in Physical Review Letters, 94 (2005

    Qualidade de Sementes de Soja BRS Candeia e BRS Tracajá Colhidas em Área de Cerrado de Roraima em Função do Tamanho.

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    bitstream/item/57170/1/BPD-28-2010-ID-76.pd

    Doenças de fruteiras tropicais de importância quarentenária na Bahia.

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    Dentre os diversos segmentos agrícolas da Bahia, destaca-se o da fruticultura como aquele considerado de importÔncia econ¶mica tanto pela produþÒo de frutas para exportaþÒo como a de produþÒo familiar que, juntas, abarcam um grande contigente de trabalhadores no Estado. A Bahia destaca-se na produþÒo de frutas tropicais com ßrea plantada de aproximadamente 270 mil hectares. Produz cerca de quatro milh§es de toneladas por ano, correspondendo a 12% da produþÒo do paÝs e 47% da regiÒo Nordeste, gerando um neg¾cio de 1,4 bilh§es de reais. Dentre as frutas produzidas no Estado, destacam-se, entre outras, a produþÒo de mamÒo, citros e banana. Importantes doenþas acometem o sistema produtivo destas fruteiras no estado. Algumas delas constituem fator de risco ou limitam a exportaþÒo de nossas frutas para alguns mercados internacionais. Outras sÒo consideradas quarentenßrias e sÒo motivo de constante fiscalizaþÒo pela AgÛncia Estadual de Defesa Agropecußria da Bahia (Adab) bem como de outras importantes instituiþ§es de pesquisa e extensÒo presentes na Bahia, como a Embrapa Mandioca e Fruticultura Tropical e a Empresa Baiana de Desenvolvimento Agropecußrio (EBDA).bitstream/item/28996/1/BARBOSAID27504.pdfDisponivel em: Acesso em: 28 fev. 2011

    Liquid crystal phase and waterlike anomalies in a core-softened shoulder-dumbbells system

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    Using molecular dynamics we investigate the thermodynamics, dynamics and structure of 250 diatomic molecules interacting by a core-softened potential. This system exhibits thermodynamics, dynamics and structural anomalies: a maximum in density-temperature plane at constante pressure and maximum and minimum points in the diffusivity and translational order parameter against density at constant temperature. Starting with very dense systems and decreasing density the mobility at low temperatures first increases, reach a maximum, then decreases, reach a minimum and finally increases. In the pressure-temperature phase diagram the line of maximum translational order parameter is located outside the line of diffusivity extrema that is enclosing the temperature of maximum density line. We compare our results with the monomeric system showing that the anisotropy due to the dumbbell leads to a much larger solid phase and to the appearance of a liquid crystal phase. the double ranged thermodynamic and dynamic anomalies.Comment: 14 pages, 5 figure

    Doenças de fruteiras tropicais na Bahia.

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    Dentre os diversos segmentos agrícolas da Bahia, destaca-se o da fruticultura como aquele considerado de importância econômica tanto pela produção de frutas para exportação como a de produção familiar que, juntas, abarcam um grande contigente de trabalhadores no Estado. A Bahia destaca-se na produção de frutas tropicais com área plantada de aproximadamente 270 mil hectares. Produz cerca de quatro milhões de toneladas por ano, correspondendo a 12% da produção do país e 47% da região Nordeste, gerando um negócio de 1,4 bilhões de reais. Dentre as frutas produzidas no Estado, destacam-se, entre outras, a produção de mamão, citros e banana.bitstream/item/25864/1/-www.nordesterural.com.br-nordesterural-matLer.asp-newsIdID27250.pdfDisponível em: Acesso em: 21 jan. 2010

    Agroecologia: manejo de pragas e doenças de plantas.

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    Agroecologia é uma ciência em construção que busca modificar o curso alterado dos processos de uso e manejo dos recursos naturais, de forma a ampliar a inclusão social, reduzir os danos ambientais, fortalecer a autonomia e segurança alimentar. Sendo assim, exige dos extensionistas, agricultores e pesquisadores a modificação dos sistemas de produção que causam degradação social e ecológica. Para tanto, faz-se necessário pensar no sistema agrícola ao longo do tempo, a partir do conhecimento popular que, integrado ao conhecimento científico, poderá transformar a realidade local, melhorando, sobretudo, a qualidade de vida das pessoas

    Thermochemical pre- and biological co-treatments to improve hydrolysis and methane production from poultry wastes

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    Poultry industry wastes, namely feathers and poultry litter, are an interesting source of substrate for biogas production. The aim of this work was to assess the biomethane potential of raw poultry wastes, as well as the possibility of enhancing this potential by favouring the hydrolysis of cellulolytic and proteinaceous material in the wastes by using bioaugmentation and thermochemical pre-treatments. Biomethane production from poultry litter and chicken feathers was assessed in batch assays. Pre-treatment with lime and sodium hydroxide was performed at different temperatures and pressures. Clostridium cellulolyticum, C. saccharolyticum and C. thermocellum were used as bioaugmentation strains in the anaerobic digestion of poultry litter. Fervidobacterium pennivorans was used to aid the hydrolysis of poultry feather. Anaerobic digestion of the raw wastes allowed a methanisation percentage (MP) of 17±2 and 33±5%, respectively from poultry litter and chicken feathers, with 2.5% total solids. The major increase in biomethanisation of poultry litter was reached after the thermochemical pre-treatment with Ca(OH)2 (90 °C, 1.27 bar, 120 minutes), with an increase of 15% in the MP comparatively with the raw wastes MP. For the poultry feathers waste, none of the implemented strategies contributed to the optimization of methane production. However, it was observed that all treatments have contributed to a significant increase in the wastes solubilisation. Therefore, the conversion of soluble organic matter to methane was the limiting step of the anaerobic digestion process of poultry wastes

    Avaliação das variações no tempo de relaxação da água em bananas durante o amadurecimento.

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    bitstream/CNPDIA-2010/12619/1/CiT47-2009.pd

    Maize (Zea mays L) cultivars nutrients concentration in leaves and stalks

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    There is pressure for crop residue removal for use as biofuel, animal feed, animal bedding and many other func¬tions which may increase nutrient export. However, there is little information about nutritional composition of maize stover considering the wide variability of cultivars used. The aim of this study was to evaluate the influence of maize cultivar on macronutrient (P, K, Ca, and Mg), micronutrient (Fe, Mn, Zn, and Cu) and Na concentration in leaves and stalks. We selected five pairs of cultivars, ranging from creole to high potential hybrid (creole, commer¬cial variety, single, double and triple cross hybrid). The cultivars were cropped under field conditions in high fertile Rhodic Ferralsol Eutric during two growing seasons. The first was characterized by severe drought (2005/2006) while the second with an abundant water supply (2006/2007). The leaf and stalk concentrations of P, K, Ca, Mg, Fe, Mn, Na, Zn, Cu, and C/P ratio were quantified at maturation stage. The results indicated that the P concen¬tration in leaves and stalks was inversely related to the technological level when simple hybrid was compared to creole cultivars. Similar behavior was observed for K in the leaf and stalk tissues. For Ca, Mg, Fe, Mn, Zn, Cu, and Na, it was not possible to establish the influence of maize selection. The C/P ratio of leaves and stalks underwent influence of the technological level with high values for simple hybrids. Maize selection seems to decrease P and K concentration for two major residue fractions, leaves and stalks
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