573 resultados para Fixação biológica de nitrogênio


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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A avaliação dos atributos químicos e físicos do solo é necessária em estudos que exploram intensivamente os sistemas de pastejo. No presente trabalho, objetivou-se avaliar as variações nos atributos físicos e químicos de um Argissolo cultivado com capim-milênio, sob pastejo, no intervalo compreendido entre outubro/2001 e maio/2002, no quinto ano de aplicação sucessiva das seguintes doses de N: 0, 150, 300 e 450 kg ha-1. Após os cinco anos de aplicação de 450 kg ha-1 de N, o teor de MO aumentou em 5 g dm-3, o que resultou em aumento da CTC. No período de outubro/2001 a maio/2002 houve diminuição nos valores de pH e de V com a aplicação de N. A densidade do solo variou pouco com a adubação nitrogenada; a percentagem de microporos aumentou e a de macroporos diminuiu na camada de 0-5 cm com o aumento das doses de N, mas a porosidade total permaneceu constante; e a resistência à penetração, quando o solo apresentava 90 g kg-1 de água, não foi afetada pelas doses de N e não foi restritiva ao crescimento das plantas.

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This work deals with the synthesis, spectroscopic characterization of mono and polynuclear Pd(II) compounds obtained from the reaction between [PdCl2(MeCN)2] precursor and imidazolidine-2-thione (L1) and benzimidazoline-2-thione (L2). The interaction between [PdCl2(MeCN)2] and imidazolidine-2-thione, in the 1:2 molar ratio, using MeOH as solvent, yielded compound [Pd2Cl4(L1)4]Cl2 (1) whereas the complex [Pd2Br4(L1)4]Br2 (2) was obtained from the reaction between 1 and Br- ions. Binuclear compounds of general formulae [Pd2(L2)4]X23/2 MeOH {X= Cl-(3), Br-(4)} were synthesized using benzimidazoline-2-thione as ligand, employing the same procedure used in the synthesis of 1 and 2, respectively. The new complexes 1-4 are crystalline, air stable and soluble in methanol and dmso. The compounds were characterized by elemental analysis, IR spectroscopy, ESI/MS mass spectrometry and thermogravimetry. Coordination of the ligands L1 and L2 via sulphur atom was evidenced by the shift of the CS band (~499 cm-1, 1 and 2; ~620 cm-1, 3 and 4) to lower frequencies in comparison with those found in the free ligands (510 cm-1, L1; 660 cm-1, L2), indicating the weakening of the CS bom after coordination. ESI/EM mass spectra (positive mode) of the complexes 1-4 allowed atribute the molecular formulae [Pd2X4(L1)4]X2 {X= Cl-(1), Br-(2)} and [Pd2(L2)4]X2 {X= Cl-(3), Br-(4)} by the appearance of the peaks at m/z 794,61 [(1) + MeOH]+, m/z 836,77 [(2) - 2H - L1]+, m/z 810 [(3) - 2Cl]+, m/z 810 [(4) - 2Br]+. The TG-DTA curves showed that the complexes 1 and 2 are thermally stable up to 212 and 169º C, respectively, and further decompose to metallic palladium at 527º C (1, obt. 28,46 %; calcd. 27,88%) and 895º C (2, obt. 22,85 %; calcd. 22,62%). Compounds 3 and 4 exhibited an initial mass loss of ~5% between 25 -146º C related to the release of metanol molecules. The complexes 3...Fujimura Leite.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The maxillofacial prosthetic rehabilitation aims of individuals with craniofacial deformities resulting from trauma, congenital malformations or tumors. Many researches have been done to improve the stability and retention of dentures in patients. With the advent of osseointegration, the maxillofacial prosthesis suffered a major advance making possible the realization of prosthetic works with stability, aesthetic quality and predictable results. This paper reviews the literature regarding the use of zygomatic implants in the fixation of maxillofacial prostheses.

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The aim of this study was to evaluate the biological properties and biocompatibility of bovine non-demineralized lyophilized and composite bones implanted in tibiae bone cavities and at the subcutaneous level. Twenty-four rats were used and sacrificed 15 and 45 days later. At the subcutaneous level, after 15 days an inflammatory reaction was seen around biomaterial particles with the presence of giant cells and at 45 days fibrous connective tissue had also developed. No signs of ectopic bone formation were observed at tibiae regions; more bone neoformation was observed at the control group (15 days) with 42.8% of the outer cortex layer against 22.6% at Orthogen and 25% at GenMix groups. At 45 days, correspondent values for bone neoformation were 62.5% at control, 26% at Orthogen, and 35% at GenMix groups, respectively. It can be concluded that both materials tested were biocompatible aiming to bone neoformation by their osteoconductive properties with no ectopic formation sites observed.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The Municipal Biological Reserve of Serra do Japi shelters an important forest remnant of Atlantic Rainforest in the state of São Paulo. For its ecological importance, were created instruments for environmental and territorial management of the Conservation Unit, with the regulation of the use and occupation of the land in its Buffer Zone (BZ) in 2004. The objective of this study was to analyze the evolution of the land cover in the BZ region of the Municipal Biological Reserve of Serra do Japi in Jundiaí-SP, between 1989 and 2010. It was used in this study the image analysis of the satellite LANDSAT-TM5, with the help of software ILWIS and IDRISI. The results showed that urban occupation has increased 37.47% and the agro pastoral and reforestation areas have decreased 36.62% and 72.22% respectively, while forest areas have increased 49.57%. However, the relative importance of the forest area in BZ ranged from 46.60% in 1989 to 69.71% in 2010, leading to the conclusion that this region was favored by changes in land cover in the period evaluated, despite strong pressure for urban expansion in its surroundings.

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Pós-graduação em Agronomia (Produção Vegetal) - FCAV

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Pós-graduação em Agronomia (Agricultura) - FCA