952 resultados para Antena de fenda em U


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The radioactivity due to 238U and 234U in three aquifer systems occurring within the Paraná sedimentary basin, South America, has been investigated. Uranium is much less dissolved from fractured igneous rocks than from the porous sedimentary rocks as indicated by the U-mobility coefficients between 7. 6 × 10-6 and 1. 2 × 10-3 g cm-3. These values are also compatible with the U preference ratios relative to Na, K, Ca, Mg and SiO2, which showed that U is never preferentially mobilized in the liquid phase during the flow occurring in cracks, fissures, fractures and faults of the igneous basaltic rocks. Experimental dissolution of diabase grains on a time-scale laboratory has demonstrated that the U dissolution appeared to be a two-stage process characterized by linear and second-order kinetics. The U dissolution rate was 8 × 10-16 mol m-2 s-1 that is within the range of 4 × 10-16-3 × 10-14 mol m-2 s-1 estimated for other rock types. The 234U/238U activity ratio of dissolved U in solutions was higher than unity, a typical result expected during the water-rock interactions when preferential 234U-leach from the rock surfaces takes place. Some U-isotopes data allowed estimating 320 ka for the groundwater residence time in a sector of a transect in São Paulo State. A modeling has been also realized considering all U-isotopes data obtained in Bauru (35 samples), Serra Geral (16 samples) and Guarani (29 samples) aquifers. The results indicated that the Bauru aquifer waters may result from the admixture of waters from Guarani (1. 5 %) and Serra Geral (98. 5 %) aquifers. © 2012 Springer-Verlag.

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Zircon samples from the Cenozoic São Paulo and Taubaté Basins and Mantiqueira Mountain Range (southeast Brazil) were concomitantly dated by zircon Fission Track Method (FTM) and in situ U-Pb dating method. While FTM detrital-zircon data are ideally used to provide low-temperature information, U-Pb single detrital grain ages record the time of zircon formation in igneous or high grade metamorphic environments. This methodology may be used to study the possible sources of the basins sediments. The results suggest that the São Paulo Basin is composed of sediments from just one source, the Mantiqueira Mountain Range. On the other hand, the Taubaté Basin presents further sediment sources besides the Mantiqueira Mountain Range. © 2012 Elsevier Ltd. All rights reserved.

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We verify that SU(N)TC⊗ - SU(3) L⊗ - U(1)X models, where the gauge symmetry breaking is totally dynamical and promoted by the non-Abelian technicolor group and the strong Abelian interactions, are quite constrained by the LHC data. The theory contains a T quark self-energy involving the mixing between the neutral gauge bosons, which introduces the coupling between the light and heavy composite scalar bosons of the model. We determine the lightest scalar boson mass for these models from an effective action for composite operators, assuming details about the dynamics of the strong interaction theories. Comparing the value of this mass with the ATLAS and CMS observation of a new boson with a mass M∼125 GeV and considering the lower bound determined by the LHC Collaboration on the heavy neutral gauge boson (Z′) present in these models, we can establish constraints on the possible models. For example, if SU(N)TC≡SU(2)TC, with technifermions in the fundamental representation, the model barely survives the confrontation with the LHC data. © 2013 American Physical Society.

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The leaf spot (Mycosphaerella leaf disease = MLD) caused by Teratosphaeria nubilosa has caused damage in eucalypt plantations in southern and southeastern Brazil. The need to assess the disease in the field to evaluate of this damage, efficiency control, evaluation of germplasm induces to the necessity of having a visual scale for evaluation of disease. The objective was to develop a diagrammatic scale for young leaves and one for adult leaves of Eucalyptus globules for MLD. To do so, the leaves collected in the field were scanned for image analysis. The damaged area, the healthy leaf area and the external area of the same scale RGB (Red, Green, Blue) were determined. Subsequently, it was determinate the levels of severity depending on the sample distribution with seven levels for young leaves and six for adult leaves. For the visual acuity test and validate the scale, the leaves were evaluated for severity, with and without scale. With this proposed scales, the assessors showed good accuracy both for young and adult leaves with R2=0,98 and R2=0,80, respectively. The importance of the development of diagrammatic scales for assessing MLD in eucalyptus must to the fact that allows quantification of the symptoms accurately and precisely.

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The area between São Paulo and Porto Alegre in southeastern Brazil plays a key area to understand and quantify the evolution of the South Atlantic passive continental margin (SAPCM) in Brazil. In this contribution, we present new thermochronological data attained by fission-track and (U-Th-Sm)/He analysis on apatites and zircons from metamorphic, sedimentary and intrusive rocks. The zircon fission-track ages range between 108.4 (15.0) and 539.9 (68.4). Ma, the zircon (U-Th-Sm)/He ages between 72.9 (5.8) and 525.1(2.4). Ma, whereas the apatite fission-track ages range between 40.0 (5.3) and 134.7 (8.0). Ma, and the apatite (U-Th-Sm)/He ages between 32.1 (1.5) and 93.0 (2.5). Ma. The spatial distribution of these ages shows three distinct blocks with a different evolution cut by old fracture zones. While the central block exhibits an old stable block, the Northern and especially the Southern block underwent complex post-rift exhumation. The sample of the Northern block shows two distinct cooling phases in the Upper Cretaceous and the Paleogene to Neogene. After sedimentation of the Permian sandstones the samples of the Central block were never heated up over 100. °C with a following moderate to fast cooling phase in Cretaceous to Eocene time and a fast cooling between Oligocene to Miocene. The five thermal models obtained in the Southern block indicate a complex evolution with three cooling phases. The exhumation events of the three blocks correspond with the Paraná-Etendekka event, the alkaline intrusions due to the Trinidad hotspot, and the evolution of the continental rift basins in SE Brazil and are, therefore, most likely to be the major force for the post-rift evolution of the passive continental margin in SE Brazil, which therefore corresponds to the three main phases of the Andean orogeny. © 2013 Elsevier B.V.

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Pós-graduação em Artes - IA

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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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

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Access to Latin American and Caribbean Exports in the United States market, 2001-2002 is the seventh annual report released by the ECLAC Washington Office, updating information contained in previous reports. Its aim is to compile and make available information on trade inhibiting measures that Latin American and Caribbean exports encounter in the United States market. This report needs to be placed in the context of a trade relationship between the United States and Latin America and the Caribbean, which has grown strongly over the years to the benefit of both economies. Moreover, it must be viewed against the background of the commitment to achieve the Free Trade Area of the Americas (FTAA), through which barriers to trade and investment will be progressively eliminated. In this regard, it is hoped that this report will further contribute to transparency and the elimination of obstacles to the free flow of trade in the Americas. The classification of trade inhibiting measures follows the definition used in the U.S. Trade Representatives (USTR) yearly publication National Trade Estimate Report on Foreign Trade Barriers. Based on this structure, the report focuses on the three areas of greatest relevance for Latin America and the Caribbean: Imports Policies (e.g., tariffs and other import charges, quantitative restrictions, import licensing, customs barriers). Standards, testing, labeling and certification (e.g., unnecessarily restrictive application of phytosanitary standards). Export subsidies (e.g., export financing on preferential terms and agricultural export subsidies that displace other foreign exports in third country markets).

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Access to Latin American and Caribbean Exports in the United States market, 2001-2002 is the eighth annual report released by the ECLAC Washington Office, updating information contained in previous reports. Its aim is to compile and make available information on trade inhibiting measures that Latin American and Caribbean exports encounter in the United States market. This report needs to be placed in the context of a trade relationship between the United States and Latin America and the Caribbean, which has grown strongly over the years to the benefit of both economies. Moreover, it must be viewed against the background of the commitment to achieve the Free Trade Area of the Americas (FTAA), through which barriers to trade and investment will be progressively eliminated. In this regard, it is hoped that this report will further contribute to transparency and the elimination of obstacles to the free flow of trade in the Americas. The classification of trade inhibiting measures follows the definition used in the U.S. Trade Representatives (USTR) yearly publication National Trade Estimate Report on Foreign Trade Barriers. Based on this structure, the report focuses on the three areas of greatest relevance for Latin America and the Caribbean: Imports Policies (e.g., tariffs and other import charges, quantitative restrictions, import licensing, customs barriers). Standards, testing, labeling and certification (e.g., unnecessarily restrictive application of phytosanitary standards). Export subsidies (e.g., export financing on preferential terms and agricultural export subsidies that displace other foreign exports in third country markets).

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Pós-graduação em Geologia Regional - IGCE

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)