973 resultados para Clay, Laura--1849-1941
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An investigation of the quantitative composition of the coarse (> 40 µm) and clay (< 2 µm) fraction of HPC 532, DSDP Leg 75, in 1300 m water depth on the eastern Walvis Ridge off Southwest Africa yielded the following results: (1) The sediments reflect a complete Latest Miocene to Recent depositional history. Sedimentation rates vary between 2.3 and 7.8 cm/ka. (2) Preservation of calcium carbonate is subject to strong variations: short-term (< 100,000 years) and long-term (about 1 m.y.) cycles in carbonate dissolution have been observed, with strongest dissolution occurring during periods of lowered sea level. (3) Upwelling influence from the near-coastal upwelling centre has been detected by means of the opal content: interglacial periods show high opal contents, because the Benguela Current turned westward at about 20°S and carried opal-laden upwelled water to the west. Sediments from glacial periods, however, show opal minima. Besides these short-term cyclic variations in opal content, long-term cycles have been found, with maximum upwelling influence in the latest Pliocene/early Quaternary. (4) Each CaCO3 dissolution minimum (maximum) is correlated with an opal maximum (minimum) throughout the sediment sequence. (5) The oceanographic system off southwest Africa remained essentially unchanged since the latest Miocene: sea level rose and fell periodically on a small and on a large scale, and the Benguela Current flowed southeast-northwest and turned to the west at the latitude of Site 532 during interglacial periods, when sea level was high. (6) The climate in the near-coastal area of southwest Africa in the latitude of Site 532 has probably been arid throughout the investigated period.
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Fil: Peretó Rivas, Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas
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Fil: Roig, Arturo Andrés.
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Fil: Martin De Blassi, Fernando.
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Fil: Zembrino, Anna.
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Fil: Molina, Hebe Beatriz. CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas) - Universidad Nacional de Cuyo
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En Argentina, los primeros ensayos de voto directo en las elecciones internas de los partidos políticos tuvieron lugar en las décadas del treinta y el cuarenta del siglo XX. Con anterioridad, los candidatos eran elegidos por notables que imponían sus decisiones en las convenciones partidarias. En este artículo, se plantea analizar su implementación en Córdoba por la UCR y el Partido Demócrata, a partir de una coyuntura cuya relevancia trascendía los límites provinciales: las últimas elecciones parlamentarias nacionales antes del golpe militar de junio de 1943. La reconstrucción historiográfica muestra sus alcances así como las resistencias a la democratización en ambos partidos.