916 resultados para Magma Types
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Estimates of terrestrial biomass depend critically on reliable information about the specific gravity of the wood of forest trees. The study reported on here was carried out in the southern Peruvian Amazon and involved collection of wood samples from trees (70 spp.) in intact forest stands. Results demonstrate the high degree of variability in specific gravity (ovendry weight/green volume) in trees at single locations. Three forest types (swamp, high terrace forest with alluvial soil, and sandy-soil forest) had values close to the average reported for tropical forest woods (.69). Two early successional forest types, which make up as much as 12% of the total vegetated area in this part of the Amazon, had values significantly lower (.40). An increase in specific gravity with increasing age of the tree, which has been reported in some spe cies of tropical-forest woods, is seen in a positive relationship between specific gravity and di ameter for a species prevalent in one plot. Increases in specific gravity with tree and forest age may be significant in estimating changes in carbon stores over time.
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An organization manages to regulate, standardize and optimize its operations in a way that places health and safety first by considering Health, Safety, Environment and Ergonomics (HSEE). In order to provide a theoretical foundation for Companies’ Occupational Health and Safety Internal Structures (COHSIS) allowing the focus on safety, COHSIS and its fundamentals were reviewed and described based on a brief literature review, which have included both papers published in journals, as well as works made available by selected organizations with mature safety culture. Three COHSIS were defined for description of its fundamentals, enabling improve the usability of its terminologies and provide the mentioned theoretical foundation.
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In this work, a new steel heated pultrusion die was designed, developed and manufactured to produce U200 glass fibre reinforced thermosetting matrix (GRP) profiles. The finite element analysis (FEA) was used to predict and optimise the developed die heating by using cylindrical electrical powered cartridges. To assess the new die performance it was mounted in the 120 kN pultrusion line of the Portuguese company Vidropol SA and used to produce continuously U200 profiles able to meet all requirements specified for the E23 grade accordingly to the European Standard EN 13706: 2002. After setting up the type, orientation and sequence of layers in the U 200 laminate, different types of thermosetting resins were used in its production. Orthophthalic, isophthalic and bisphenolic unsaturated polyester as well as vinylester resins were used to produce glass fibre reinforced U 200 composite profiles. All applied resins were submitted to SPI gel tests in order to select the more appropriated catalyst system and optimise the processing variables to be used in each case, namely, pultrusion pull-speed and die temperature. The best pultrusion operational conditions were selected by varying and monitoring the pull-speed and die temperature and, at the same time, measuring the temperature on the manufactured U 200 profile during processing. Finally, the produced U200 profiles were submitted to visual inspection, calcination and mechanical tests, namely, flexural, tensional and interlaminar shear strength (ILSS) tests, to assess their accomplishment with the EN 13706 requirements.
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Dissertação de mestrado em Genética Molecular
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OBJECTIVE: To assess the effect of different types of lipid diets on the lipid metabolism of aging rats. METHODS: Fifty male Wistar rats were studied from the time of weaning to 12 and 18 months of age. Their diets were supplemented as follows: with soybean oil (S), canola oil (CA), lard and egg yolk (LE), and canola oil + lard and egg yolk (CA + LE). Blood pressure (BP) was measured every month, and the heart/body ratio (H/BR) was determined. The rats were euthanized at the age of 12 and 18 months, and blood samples were collected for lipid analysis as follows: total cholesterol (TC), LDL-C, VLDL-C, HDL-C, triglycerides (TG), and glucose. RESULTS: The type of oil ingested by the animals significantly altered BP, H/BR, and serum lipid levels in rats at 12 and 18 months. No difference was observed in the survival curve of the animals in the different groups. The LE group had the highest BP, and the CA group was the only one in which BP did not change with aging. A reduction in the H/BR was observed in the LE and CA+LE animals. At the age of 12 months, differences in TC, HDL-C, LDL-C, VLDL-C, TG, and glucose were observed. At the age of 18 months, a significant difference in TC, HDL-C, and glucose was observed. The highest TC value was found in the CA group and the lowest in the S group. CONCLUSION: No increase in BP occurred, and an improvement was evident in the lipid profile of rats fed a diet supplemented with CA, in which an elevation in HDL-C levels was observed, as compared with levels with the other types of diet.
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El batolito de Achala es uno de los macizos graníticos más grandes de las Sierras Pampeanas, el cual se localiza en las Sierras Grandes de Córdoba. Si bien el batolito de Achala ha sido objeto de diversos estudios geológicos, principalmente debido a sus yacimientos de uranio, el mismo todavía no posee un inequívoco modelo petrogéntico. Tampoco existe, en la actualidad, un inequívoco modelo que explique la preconcentración de uranio en las rocas graníticas portadores de este elemento. Este Proyecto tiene como objetivo general realizar estudios petrológicos y geoquímicos en la región conocida como CAÑADA del PUERTO, un lugar estratégicamente definido debido a la abundancia de granitos equigranulares de grano fino y/o grano medio biotíticos, emplazados durante el desarrollo de cizallas magmáticas tardías, y que constituirían las rocas fuentes de uranio. El objetivo específico requiere estudios detallados de las diferentes facies del batolito de Achala en el área seleccionada, incluyendo investigaciones petrológicas, geoquímicas de roca total, geoquímica de isótopos radiactivos y química mineral, con el fin de definir un MODELO PETROGENÉTICO que permita explicar: (a) el origen del magma padre y el subsiguiente proceso de cristalización de las diferentes facies graníticas aflorantes en el área de estudio, (b) identificar el proceso principal que condujo a la PRECONCENTRACIÓN uranífera de los magmas graníticos canalizados en las cizallas magmáticas tardías. Ambos objetivos se complementan y no son compartimentos estancos, ya que el logro combinado de estos objetivos permitirá comprender de mejor manera el proceso geoquímico que gobernó la distribución y concentración del U. De esta manera, se intentará definir un MODELO de PRECONCENTRACIÓN URANÍFERA EXTRAPOLABLE a otras áreas graníticas enriquecidas en uranio, constituyendo una poderosa herramienta de investigación aplicada a la exploración uranífera. En particular, el conocimiento de los recursos uraníferos es parte de una estrategia nacional con vistas a triplicar antes del 2025 la disponibilidad energética actual, en cuyo caso, el uranio constituye la materia prima de las centrales nucleares que se están planificando y en construcción. Por otro lado, la Argentina adhirió al Protocolo de Kioto y, junto a los países adherentes, deben disminuir de manera progresiva el uso de combustibles fósiles (que producen gases de efecto invernadero), reemplazándola por otras fuentes de energía, entre ellas, la ENERGÍA NUCLEAR. Este Proyecto, si bien NO es un Proyecto de exploración y/o prospección minera, es totalmente consistente con la política energética nacional promocionada desde el Ministerio de Planificación Federal, Inversión Pública y Servicios (v. sitio WEB CNEA), que ha invertido, desde 2006, importantes sumas de dinero, en el marco del Programa de Reactivación de la Actividad Nuclear.Los estudios referidos serán conducidos por los Drs. Dahlquist (CONICET-UNC) y Zarco (CNEA) quienes integrarán sus experiencias desarrolladas en el campo de las Ciencias Básicas con aquel logrado en el campo de las Ciencias Aplicadas, respectivamente. Se pretende, por tanto, aplicar conocimientos académicos-científicos a un problema de geología con potencial significado económico-energético, vinculando las instituciones referidas, esto es, CONICET-UNC y CNEA, con el fin de contribuir a la actividad socioeconómica de la provincia de Córdoba en particular y de Argentina en general.Finalmente, convencidos de que el progreso de la Ciencia y el Desarrollo Tecnológico está íntimamente vinculada con la sólida Formación de Recursos Humanos se pretende que este Proyecto contribuya SIGNIFICATIVAMENTE a las investigaciones de Doctorado que iniciará la Geóloga Carina Bello, actual Becaria de la CNEA.
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Se propone el estudio de galaxias en diferentes tipos de sistemas para lograr un mejor entendimiento de los procesos físicos que actúan en la formación y evolución de estas galaxias. En particular, se analizarán las propiedades de galaxias en cúmulos, grupos difusos, grupos compactos y grupos fósiles. Para el desarrollo de este trabajo, se utilizarán catálogos observacionales públicos y propios, simulaciones cosmológicas combinadas con modelos semianalíticos y catálogos sintéticos basados en dichas simulaciones. Entender el comportamiento de las galaxias pertenecientes a cada clase de sistema permitirá la comparación entre los distintos entornos y posteriormente, la distinción de los diferentes procesos astrofísicos que actúan.
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Magdeburg, Univ., Fak. für Informatik, Diss., 2015
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n.s. no.30(1992)
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n.s. no.17(1986)