507 research outputs found

    Parâmetros de crescimento do sorgo e do capim no consórcio Sorghum bicolor e Brachiaria brizantha cv. Marandu.

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    Objetivou-se determinar o efeito do consórcio Sorghum bicolor e Brachiaria brizantha sob os parâmetros de crescimento do sorgo e do capim. Os tratamentos utilizados foram: braquiária no plantio solteiro, sorgo no plantio solteiro, sorgo consorciado com capim na linha e entrelinhas de plantio, sorgo consorciado com capim nas entrelinhas de plantio, sorgo consorciado com capim na linha de plantio. Foi utilizado o delineamento em blocos ao acaso com cinco repetições por tratamento. O corte foi feito, aproximadamente, 108 a 110 dias após o plantio, manualmente no dia 13 de maio (111 dias após o plantio) em uma altura de 35 cm. Uma amostra de plantas de sorgo e capim braquiária foi cortada e pesada juntas para que se obtivesse o peso verde do material a ser ensilado, sendo o resultado utilizado para cálculo de produção de matéria verde por hectare. A altura das plantas foi determinada, no momento do corte, por meio da medida do nível do solo até a extremidade superior da panícula em 20% das plantas de cada parcela. Outra amostra de plantas da unidade experimental foi tomada, separadas as plantas de sorgo e capim, pesadas separadamente para obtenção do peso verde (PV) e levadas ao laboratório para secagem em estufa de circulação forçada à 65ºC para determinação do peso seco. Não houve diferença entre as médias (P>0,05), para as alturas das plantas de sorgo e de capim, mas essa diferença foi significativa para as variáveis, estande de sorgo, produção de matéria verde e seca

    Production and cash flow of oil palm intercropping systems an amazonian degraded area.

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    The objective of this study was to analyze the technical viability and cash flow of intercrop cultivation in the first three years after oil palm planting in a degraded area of the Amazon. Four intercropping systems were tested: SI - oil palm + banana; SII - oil palm + cassava; SIII - oil palm + pineapple, and SIV - oil palm in monoculture. Intercropping was performed during the first three years of oil palm planting and the cash flow of the systems evaluated during this period. The oil palm bunches production was evaluated from 7th to 10th year after planting. SIII had best financial performance, with deployment and maintenance costs 100% amortized over the three years of the system. The SI and SII systems amortized 86.7% and 64.5% of the costs, respectively. Oil palm bunches production was not affected by intercropping. Yield of intercrops was similar to that expected from the crops in monoculture. The intercropping systems evaluated provide a technically and economically viable alternative to generate income and amortize planting and maintenance costs during oil palm juvenile phase in degraded areas of the Amazon

    Host Susceptibility to Brucella abortus Infection Is More Pronounced in IFN-γ knockout than IL-12/β2-Microglobulin Double-Deficient Mice

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    Brucella abortus is a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. IFN-γ, IL-12, and CD8+ T lymphocytes are important components of host immune responses against B. abortus. Herein, IFN-γ and IL-12/β2-microglobulin (β2-m) knockout mice were used to determine whether CD8+ T cells and IL-12-dependent IFN-γ deficiency would be more critical to control B. abortus infection compared to the lack of endogenous IFN-γ. At 1 week after infection, IFN-γ KO and IL-12/β2-m KO mice showed increased numbers of bacterial load in spleens; however, at 3 weeks postinfection (p.i.), only IFN-γ KO succumbed to Brucella. All IFN-γ KO had died at 16 days p.i. whereas death within the IL-12/β2-m KO group was delayed and occurred at 32 days until 47 days postinfection. Susceptibility of IL-12/β2-m KO animals to Brucella was associated to undetectable levels of IFN-γ in mouse splenocytes and inability of these cells to lyse Brucella-infected macrophages. However, the lack of endogenous IFN-γ was found to be more important to control brucellosis than CD8+ T cells and IL-12-dependent IFN-γ deficiencies

    Determination of Kresoxim-Methyl in Water and in Grapes by High-Performance Liquid Chromatography (HPLC) Using PhotochemicalInduced Fluorescence and Dispersive Liquid-Liquid Microextraction (DLLME)

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    A high-performance chromatographic method was developed to determine the fungicide kresoxim-methyl. Off-line photochemical derivatization was used to induce the formation of a stable and fluorescent product since the fungicide does not present natural fluorescence. Intense fluorescence at 370/430nm was achieved by treating the analyte in solution at pH 6 to ultraviolet light for 45s. The chromatographic conditions included isocratic elution with 50/ 50% (v/v) acetonitrile/water and the photochemical product appeared at a retention time of 7.2min. The short and long term stabilities of the photoproduct were evaluated and variation of less than 5% was achieved. The limits of detection in water samples and in grapes samples were 0.019mg kg1 and 0.065mg kg1 of kresoxim-methyl residue, respectively. The linear response covered three orders of magnitude up to 10.6mg kg1 of kresoxim-methyl. The robustness was evaluated through a Box–Behnken experimental design showing the insignificance of all factors and their interactions. The potential interference of tebuconazole for the determination of kresoxim-methyl was studied. The use of the dispersive liquid-liquid microextraction (DLLME) allowed recoveries between 80% and 101% depending on concentration with the minimum generation of waste products

    Diagonal Ladders: A New Class of Models for Strongly Coupled Electron Systems

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    We introduce a class of models defined on ladders with a diagonal structure generated by npn_p plaquettes. The case np=1n_p=1 corresponds to the necklace ladder and has remarkable properties which are studied using DMRG and recurrent variational ansatzes. The AF Heisenberg model on this ladder is equivalent to the alternating spin-1/spin-1/2 AFH chain which is known to have a ferrimagnetic ground state (GS). For doping 1/3 the GS is a fully doped (1,1) stripe with the holes located mostly along the principal diagonal while the minor diagonals are occupied by spin singlets. This state can be seen as a Mott insulator of localized Cooper pairs on the plaquettes. A physical picture of our results is provided by a tpJpt_p-J_p model of plaquettes coupled diagonally with a hopping parameter tdt_d. In the limit tdt_d \to \infty we recover the original tJt-J model on the necklace ladder while for weak hopping parameter the model is easily solvable. The GS in the strong hopping regime is essentially an "on link" Gutzwiller projection of the weak hopping GS. We generalize the tpJptdt_p-J_p-t_d model to diagonal ladders with np>1n_p >1 and the 2D square lattice. We use in our construction concepts familiar in Statistical Mechanics as medial graphs and Bratelli diagrams.Comment: REVTEX file, 22 pages (twocolumn), 35 figures inserted in text. 12 Table

    Evaluation of HBV-Like circulation in wild and farm animals from Brazil and Uruguay.

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    The origin of the hepatitis B virus is a subject of wide deliberation among researchers. As a result, increasing academic interest has focused on the spread of the virus in different animal species. However, the sources of viral infection for many of these animals are unknown since transmission may occur from animal to animal, human to human, animal to human, and human to animal. The aim of this study was to evaluate hepadnavirus circulation in wild and farm animals (including animals raised under wild or free conditions) from different sites in Brazil and Uruguay using serological and molecular tools. A total of 487 domestic wild and farm animals were screened for hepatitis B virus (HBV) serological markers and tested via quantitative and qualitative polymerase chain reaction (PCR) to detect viral DNA. We report evidence of HBsAg (surface antigen of HBV) and total anti-HBc (HBV core antigen) markers as well as low-copy hepadnavirus DNA among domestic and wild animals. According to our results, which were confirmed by partial genome sequencing, as the proximity between humans and animals increases, the potential for pathogen dispersal also increases. A wider knowledge and understanding of reverse zoonoses should be sought for an effective One Health response

    Guia de implantação do modelo corporativo de processos de software da Embrapa (MCPSE).

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    Este Guia reúne informações para que os processos de software sejam adotados corporativamente, conforme definido no modelo corporativo de processos de software da Embrapa (MCPSE), garantindo a qualidade dos produtos gerados pelas equipes dos projetos de desenvolvimento de software da Empresa.bitstream/item/100418/1/DOC-400.pd
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