264 resultados para Fotoluminescência. Zircônia. Íons de terras raras. MPC
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A população mundial vem sofrendo, cada vez mais, as conseqüências das agressões efetuadas pelo homem ao meio ambiente, principalmente quanto à ocupação e uso inadequado das terras, o que ocasiona empobrecimento e depauperamento do solo, influenciando na qualidade e disponibilidade de água, levando à destruição das reservas florestais. Assim, é necessária a implantação de políticas públicas, que contemplem o desenvolvimento econômico, urbano, rural e social de uma região, preservando os recursos naturais para futuras gerações. A bacia em estudo está localizada entre as coordenadas UTM 764942; 7546214 e 741816; 7534759, com uma área de 14699,7ha. Este trabalho visou definir as classes de capacidade de uso de terra da microbacia do Ribeirão Pouso Alegre - Jaú (SP) através do Sistema de Informações Geográficas - SPRING. A carta de capacidade de uso da terra foi elaborada a partir do cruzamento das cartas clinográfica e de solo, que foram elaboradas pelo SIG Spring, e o cruzamento de dados foi feito através do LEGAL - Linguagem Espacial para Geoprocessamento Algébrico. Os resultados mostraram que a microbacia é constituída essencialmente pelas classes II e III e o SIG-SPRING permitiu através dos seus módulos discriminarem e quantificar as áreas das classes de terras, declive e capacidade de uso da terra rapidamente.
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We describe the nests and nesting behaviour of six little-known birds from south-central Minas Gerais, Brazil: Red-and-white Crake Laterallus leucopyrrhus (closed/ovoid/base nest with shells of white eggs), White-throated Woodcreeper Xiphocolaptes albicollis (cavity/without-tunnel/simple/platform nest with two immaculate white eggs), Southern Bristle Tyrant Phylloscartes eximius (closed/globular/lateral nest), Sharp-tailed Tyrant Culicivora caudacuta (high cup/lateral nest with three cream-coloured eggs), White-rumped Monjita Xolmis velatus (low cup/base nest with two immaculate white eggs) and Hellmayr's Pipit Anthus hellmayri (low cup/base nest with three pale brown eggs spotted dark brown).
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The lodging of some rice cultivars at harvest time can lead to significant losses in yield, and the inappropriate water and nitrogen management, under high-tech conditions, can aggravate the problem. The use of vegetal regulators is an alternative to reduce lodging, however, information on this topic are rare. The study aimed to evaluate the application of glyphosate sub doses (26 g ha -1, 52 g ha -1, 78 g ha -1, 104 g ha -1, 130 g ha -1, 156 g ha -1, and 182 g ha -1) on agronomical traits, development, and yield of upland rice crops irrigated by aspersion, during the floral differentiation period. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, through the agricultural years of 2008/2009 and 2009/2010. The increase of glyphosate sub doses, at the floral differentiation period of the Primavera cultivar, reduced the plants height, panicle size, and, consequently, yield. Sub doses higher than or equal to 78 g ha -1 eliminated the plants lodging process.
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Objective: To evaluate the influence of different air abrasion protocols on the surface roughness of an yttria-stabilized polycrystalline tetragonal zirconia) (Y-TZP) ceramic, as well as the surface topography of the ceramic after the treatment. Method: Fifty-four specimens (7.5×4×7.5mm) obtained from two ceramic blocks (LAVA, 3M ESPE) were flattened with fine-grit sandpaper and subjected to sintering in the ceramic system's specific firing oven. Next, the specimens were embedded in acrylic resin and the surfaces to be treated were polished in a polishing machine using sandpapers of decreasing abrasion (600- to 1,200-grit) followed by felt discs with 10μm and 3μm polishing pastes and colloidal silica. The specimens were then randomly assigned to 9 groups, according to factors particle and pressure(n=6): Gr1- control; Gr2- Al 2O 3(50μm)/2.5 bar; Gr3- Al 2O 3(110μm)/2.5 bar; Gr4- SiO 2(30μm)/2.5 bar; Gr5- SiO 2(30μm)/2.5 bar; Gr6- Al 2O 3(50μm)/3.5 bar; Gr7- Al2O3(110μm)/3.5 bar; Gr8- SiO 2(30μm)/3.5 bar; Gr9- SiO 2(30μm)/3.5 bar. After treatments, surface roughness was analyzed by a digital optical profilometer and the morphology was examined by scanning electron microscopy (SEM). Data (μm) were subjected to statistical analysis by Dunnett's test (5%), two-way ANOVA and Tukey's test (5%). Results: The type of particle (p=0.0001) and the pressure (p=0.0001) used in the air abrasion protocols influenced the surface roughness values among the experimental groups (ANOVA). The mean surface roughness values (μm) obtained for the experimental groups (Gr2 to Gr9) were, respectively: 0.37 D; 0.56 BC; 0.46 BC; 0.48 CD; 0.59 BC; 0.82 A; 0.53B CD; 0.67 AB. The SEM analysis revealed that Al 2O 3, regardless of the particle size and pressure used, caused damage to the surface of the specimens, as it produced superficial damages on the ceramic, in the form of grooves and cracks. Conclusion: Al2O3 (110 μm/3.5 bar) air abrasion promoted the highest surface roughness on the ceramics, but it does not mean that this protocol promotes better ceramic-cement union compared to the other air abrasion protocols.
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The growth analysis allows the characterization and understanding of the upland rice cultivars development. This study aimed at characterizing, by using the growth analysis, the physiological components and agronomic performance, as well as the differences among traditional, intermediate and modern upland rice cultivars. The experiment was conducted under upland rice conditions, favored by the use of supplementary irrigation. The experimental design was randomized blocks, with three treatments consisting of traditional (Caiapó), modern (Maravilha) and intermediate (BRS Primavera) cultivars and eight replications. The leaf area index (LAI), instantaneous growth rate (IGR), relative growth rate (RGR), net assimilation rate (NAR) and specific leaf area (SLA), as well as grain yield and yield components, were evaluated. The intermediate and traditional cultivars presented the highest total dry matter accumulation rate, while the traditional and modern ones showed the highest LAI. The intermediate cultivar presented the highest IGR, RGR, NAR and SLA levels, as well as the highest grain yield, as a consequence of the higher spikelet fertility and 1,000 grain mass.
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The Archaeological Dark Earth (ADE) soils are characterized by its high fertility, dark color, and presence of pottery fragments. Regarding the formation of ADE, the most widely accepted hypothesis is that anthropogenic processes involving pre-Columbian populations made them. The purpose of this study is to characterize ADE units located in the Southern Amazon Region, in the cities of Apuí and Manicoré. Seven ADE sites were selected, trenches opened and the soil profiles characterized morphologically. Then, samples of each horizon were collected for analyses of the following physical and chemical properties: particle size, water-dispersible clay, flocculation, soil bulk density, particle density, total porosity, pH in water and KCl solutions, Ca2+, Mg2+, K+, Al3+, available P, H+Al, and organic C. Also, total oxides, free oxides and amorphous forms were analyzed. The texture of the anthropic A horizon ranged from sandy loam to clay loam. The pottery fragments and lithic material were found in similar quantities and at similar depths in the A horizons of the studied soil profiles, suggesting some similarity between the anthropogenic factors of formation. The anthropic horizons of profiles P3, P4, and P7 had a eutrophic character and high to very high levels of available phosphorus, compared to P1, P2, P5, and P6, indicating the heterogeneity of the ADEs.
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Water deficit is one of the environmental factors that cause a great reduction in the upland rice grain yield. The objective of this study was to evaluate genotypes of upland rice with broad genetic diversity for tolerance to this stress and to identify secondary traits for evaluation of this tolerance. Sixty-four genotypes were evaluated during two years at the Experiment Station of EMATER, in Porangatu, GO, under well-watered and water deficit conditions. The genotypes showed differences in grain yield and were influenced differently by the water treatments, both under a mild water deficit in the first year and under a severe one in the second year. The genotype grain yield under water deficiency was significantly and positively correlated with tiller fertility, number of panicles m-2, 100-grain weight, and plant height, and negatively with spikelet sterility and the number of days for the occurrence of 50% panicle emergence. It was also observed that the most productive genotypes under water deficit conditions showed lower leaf temperature, indicating improved water status. Nine genotypes were productive in both water conditions and three were productive only when well-watered.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Biotecnologia - IQ
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Educação Matemática - IGCE
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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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Pós-graduação em Ciência dos Materiais - FEIS