975 resultados para 52-417D


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Raman spectroscopy complimented with infrared spectroscopy has been used to study the rare earth based mineral decrespignyite (Y,REE)4Cu(CO3)4Cl(OH)5•2(H2O) and compared with the Raman spectra of a series of selected natural halogenated carbonates from different origins including bastnasite, parisite and northupite. The Raman spectrum of decrespignyite displays three bands are at 1056, 1070 and 1088 cm-1 attributed to the CO32- symmetric stretching vibration. The observation of three symmetric stretching vibrations is very unusual. The position of CO32- symmetric stretching vibration varies with mineral composition. Raman bands of decrespignyite show bands at 1391, 1414, 1489 and 1547 cm-1. Raman spectra of bastnasite, parisite and northupite show a single band at 1433, 1420 and 1554 cm-1 assigned to the ν3 (CO3)2- antisymmetric stretching mode. The observation of additional Raman bands for the ν3 modes for some halogenated carbonates is significant in that it shows distortion of the carbonate anion in the mineral structure. Four Raman bands are observed at 791, 815, 837 and 849 cm-1and assigned to the (CO3)2- ν2 bending modes. Raman bands are observed for decrespignyite at 694, 718 and 746 cm-1 and are assigned to the (CO3)2- ν4 bending modes. Raman bands are observed for the carbonate ν4 in phase bending modes at 722 cm-1 for bastnasite, 736 and 684 cm-1 for parisite, 714 cm-1 for northupite. Multiple bands are observed in the OH stretching region for decrespignyite, bastnasite and parisite indicating the presence of water and OH units in the mineral structure.

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En 52 steel has been electroslag refined and the resultant effects of refining on its mechanical properties have been assessed. It was found that refining caused a decrease in fatigue crack growth rates and increases in fatigue strength, fracture toughness, Charpy fracture energy and tensile ductility. Fatigue crack growth rates in region I and in region III were found to be considerably lower in the electroslag refined steel: they were unaffected in region II. The fracture toughness values for the electroslag refined steel are nearly twice those estimated for the unrefined steel. Measurements on heat-treated samples have shown that the electroslag refined steel has a better response to heat-treatment. The improvement in the mechanical properties is explained in terms of the removal of nonmetallic inclusions and a reduction in the sulphur content of the steel.

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This series of research vignettes is aimed at sharing current and interesting research findings from our team of international Entrepreneurship researchers. This vignette, written by Dr Judy Matthews examines the effects of firm engagement with design innovation programs on entrepreneurial activities of small and medium enterprises.

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We report here results from detailed timing and spectral studies of the high mass X-ray binary pulsar 4U 1538-52 over several binary periods using observations made with the Rossi X-ray Timing Explorer (RXTE) and BeppoSAX satellites. Pulse timing analysis with the 2003 RXTE data over two binary orbits confirms an eccentric orbit of the system. Combining the orbitial parameters determined from this observation with the earlier measurements we did not find any evidence of orbital decay in this X-ray binary. We have carried out orbital phase resolved spectroscopy to measure changes in the spectral parameters with orbital phase, particularly the absorption column density and the iron line flux. The RXTE-PCA spectra in the 3-20 keV energy range were fitted with a power law and a high energy cut-off along with a Gaussian line at similar to 6.4 keV, whereas the BeppoSAX spectra needed only a power law and Gaussian emission line at similar to 6.4keV in the restricted energy range of 0.3-10.0 keV. An absorption along the line of sight was included for both the RXTE and BeppoSAX data. The variation of the free spectral parameters over the binary orbit was investigated and we found that the variation of the column density of absorbing material in the line of sight with orbital phase is in reasonable agreement with a simple model of a spherically symmetric stellar wind from the companion star.

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Here we report chromium isotope compositions, expressed as delta Cr-53/ 52 in per mil (&) relative to NIST 979, measured in selected Cr-rich minerals and rocks formed by the primary magmatic as well as the secondary metamorphic and weathering processes. The main objectives of this study were: (i) to further constrain the isotope composition of the Earth's mantle Cr inventory and its possible variation during geological history, based on the analysis of globally distributed and stratigraphically constrained mantle-derived chromites; and (ii) to investigate the magnitude and systematics of Cr isotope fractionation during oxidative weathering and secondary alteration (i. e., hydration, serpentinization) of the magmatic Cr sources. Specifically, we analyzed delta Cr-53/ 52 in a set of globally distributed mantle-derived chromites (FeMgCr2O4, n = 30) collected from various locations in Europe, Asia, Africa and South America, and our results confirm that a chromite-hosted Earth's mantle Cr inventory is uniform at - 0.079 +/- 0.129& (2SD), which we named here as a ` canonical' mantle d 53/ 52 Cr signature. Furthermore our dataset of stratigraphically constrained chromites, whose crystallization ages cover most of the Earth's geological history, indicate that the bulk Cr isotope composition of the chromite-hosted mantle inventory has remained uniform, within about +/- 0.100&, since at least the Early Archean times (similar to 3500 million years ago, Ma). To investigate the systematics of Cr isotope fractionation associated with alteration processes we analyzed a number of secondary Cr-rich minerals and variably altered ultramafic rocks (i. e., serpentinized harzburgites, lherzolites) that revealed large positive delta Cr-53/ 52 anomalies that are systematically shifted to higher values with an increasing degree of alteration and serpentinization. The degree of aqueous alteration and serpentinization was quantified by the abundances of fluid-mobile (Rb, K) elements, and by the Loss On Ignition (LOI) parameter, which determines the amount of structurally bound water (OH/ H2O) present in secondary hydrated minerals like serpentine. Overall, we observed that altered ultramafic rocks that yielded the highest LOI values, and the lowest amounts of fluid mobile elements, also yielded the heaviest delta Cr-53/ 52 signatures. Therefore, we conclude that secondary alteration (i.e., hydration, serpentinization) of ultramafic rocks in near-surface oxidative environments tend to shift the bulk Cr isotope composition of the weathered products to isotopically heavier values, pointing to a dynamic redox cycling of Cr in the Earth's crustal and near-surface environments. Hence, if validated by future

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Se realizó un estudio para determinar la variabilidad genética de 35 accesiones de yuca colectadas en territorio nicaragüense, se incluyó como material de referencia 14 accesiones introducidas del Centro Internacional de Agricultura Tropical (CIAT), Colombia y 3 introducidas de Brasil, con el objetivo de identificar duplicidad de accesiones y comparar la estructura genética de las accesiones colectadas en Nicaragua. Los análisis de diversidad se obtuvieron de los datos de 9 m arcadores microsatélitestipo SSR. Se detectó un total de 47 alelos en los nueve microsatélites, el número de alelos varió de 3 a 9, con un valor medio de 5. El índice de diversidad genética fue alto de 0.61. El valor promedio del PIC fue de 0.60, demostrando que los marcadores más informativos y polimórficos fueron el SSRY 100, GA-131y GA-12, con alto poder de discriminación. El análisis molecular de varianza mostró que la mayor diferencia existe dentro del grupo, no así entre grupo. La mayor distancia genética determinada entre los grupos fue entre el grupo de Matagalpa con las Internacionales, presentando menor distancia las RAAS con las Rio San Juan, mientras que el grupo de Río San Juan y RAAS, presentaron la mayor identidad genética. El análisis de conglomerado mostró un coeficiente de correlación cofenética de 0.82 el cual agrupo ó seis grupos genéticamente idénticos. La información genética obtenida permitirá reducir las accesiones idénticas y seleccionar las de interés genético, para garantizar un manejo sostenible de los recursos que se dispone en el banco de germoplasma del Centro Nacional de Investigación Agropecuaria y Biotecnología (CNIAB) del Instituto Nicaragüense de Tecnología Agropecuaria (INTA).

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Contenido: Editorial : veinte años de la revista fundada por el Dr. Santiago de Estrada – Derecho Eclesiástico: Condición jurídica del Estado de la Ciudad del Vaticano / Ariel David Busso – Derecho Comercial: La empresa y las responsabilidades emergentes de la competencia desleal / Isabel Miguez – Presentación en concurso preventivo de una (ex) entidad financiera / Javier Armando Lorente – La contenciosidad del procedimiento concursal / Claudio A. Galli – Panorama de la cooptación en el directorio privado en el Derecho Comparado / Mariano Gagliardo – Sobre los fundamentos: Teoría política de la costumbre y de la codificación : Montesquieu y la doble cultura jurídica en la antigua Francia / Paul-Ludwig Weinacht (traducción del Prof. Dr. Hugo Laitenberger) Universidad de Würzburg – Las certezas del sentido común y los caracteres esenciales de la pena / Mauro Ronco. Universidad de Modena, traducción de Alfredo Battaglia y comentario de Luis María Rizzi: “La pena como retribución y redención” – In memoriam – Documentos: Portada, índice y primer editorial del Nº 1 de “Prudentia Juris” en agosto de 1980 -- Recensiones

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Reúne as informações pessoais e sobre a vida profissional e política dos 513 deputados eleitos no pleito de outubro de 2002, no momento inicial da 52ª Legislatura, tendo por objetivo constituir-se em importante fonte de pesquisa e de preservação da memória da Câmara dos Deputados

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Estudo do sistema de comissões e seu poder de apreciação conclusiva: origem histórica e aplicação na Câmara dos Deputados. Pesquisa de dados sobre a tramitação dos projetos de lei sujeitos à competência plena das comissões apresentados na 52ª Legislatura. Análise comparativa dos dados em relação a estudos anteriormente realizados.

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Analisa a atividade legislativa da Comissão de Seguridade Social e Família durante a 52ª Legislatura (2003-2006) e sua relação com as perspectivas informacional e distributivista da teoria do Novo Institucionalismo.

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Investiga o discurso parlamentar dos representantes legislativos do Distrito Federal na Câmara dos Deputados, entre os anos 2003 e 2007, em relação às mudanças necessárias na educação.

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Apresenta um estudo comparativo da Legislatura de 1987 e de 2003 da Câmara dos Deputados Federal, tomando como ponto de partida o levantamento de dados das duas legislaturas citadas. Utiliza-se especificamente o indicador da profissão de cada parlamentar eleito e também dos parlamentares suplentes que ingressaram no decorrer das referidas legislaturas. Objetiva verificar como está a representação dos cidadãos na Câmara dos Deputados, se a Câmara no decorrer de doze anos está mais popular ou mais elitista. Apresenta ainda a discussão a respeito da democracia no Brasil feita por Norberto Bobbio e também a reflexão de Anthony Downs sobre a incerteza do eleitor no momento de escolha seus representantes. Contribui para o entendimento de como o sistema político brasileiro sofre alterações ao longo do tempo.

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Propõe a avaliação das representações apreciadas pelo Conselho de Ética e Decoro Parlamentar da Câmara dos Deputados da 52ª e 53ª Legislaturas. Com base na análise do conjunto das representações protocoladas entre os anos 2003 a 2011, pretende-se responder se os instrumentos normativos e legais são eficazes no combate à quebra de decoro ou se de alguma forma favorecem a impunidade. Identifica os dispositivos legais que tratam do decoro parlamentar, como o Código de Ética e Decoro Parlamentar da Câmara dos Deputados, a Constituição da República Federativa do Brasil e o Regimento Interno da Câmara dos Deputados. São ainda relacionados alguns processos que resultaram em perda de mandato ou que fixaram normas interpretativas.