1000 resultados para 10210953 TM-69


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A implantaçao da obrigatoriedade do acesso à escola pública de Ensino Fundamental no Brasil, a partir do final dos aos 1980, produziu uma nova realidade no sistema de ensino. Por um lado, a taxa de frequência da escola básica passou de 75,03 (1990) para 92,14 (2010). Em contrapartida, a taxa de analfabetismo de pessoas com mais de 18 anos ainda é de 10,19 e somente 54,92 das pessoas com 18 anos ou mais tem Ensino Fundamental completo. Um conjunto de contradiçoes produzidas e reproduzidas sob o enfoque da justiça escolar a qual, norteia à universalizaçao do acesso a escola básica. Neste sentido, a ideia central desse trabalho foi reconhecer o perfil socioeducacional dos alunos em situaçao de fracasso escolar (repetência, distorçao idade-série e evasao escolar) no estado brasileiro que apresenta o melhor índice desenvolvimento da escola básica. Para tanto, foram analisadas as respostas de 87.607 questionários respondidos por alunos do 9o ano, participantes da Prova Brasil 2011. Com auxílio do software SPSS, foram produzidos procedimentos estatísticos para sistematizar e ampliar a análise que teve com suporte teórico as reflexoes preconizadas por distintos autores da Sociologia da Educaçao

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El epígrafe de Romero Brest (1969) expresa la incertidumbre respecto de la Expo Internacional Novísima Poesía/69 (1969, CAV-ITDT). ¿Por qué este desconcierto ante el contenido de la exposición? ¿Qué circunstancias en esos años hacen viable la experimentación, incluyendo poesía concreta? ¿Cómo ingresa ésta en el circuito institucional? ¿Qué formas de positividad (Foucault, 1990) adquieren los términos experimentación, concretismo, vanguardia? Las conexiones de la Expo con el concretismo se producen a partir del sistema de intercambios que genera Vigo con artistas de otros países; dejan entrever las fricciones con el modo de entender la vanguardia y las inscripciones de sentido del internacionalismo

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A detailed oxygen isotope record (resolution: about 2500 years) has been obtained for the Pleistocene sediments at Hole 504. Preliminary measurements made deeper in the section suggest that at least the upper Pliocene section is also amenable to detailed stable isotope work. The record for the middle Pleistocene resembles that obtained previously from piston cores in the western equatorial Pacific, although the superior resolution of this high-accumulation-rate site reveals a greater amplitude of isotope variation than previously observed. The record for the lower Pleistocene reveals variation that is both greater in amplitude and higher in frequency than apparent from previously analyzed piston cores. The site provides the best material recovered to date for the study of the evolution of climatic variability during the past few million years.

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Primary sulfide mineralization in basalts of the Costa Rica Rift occurs mainly in chrome-spinel-bearing olivine tholeiites. Primary sulfides form both globules, consisting of quenched single-phase solid solutions, and irregular polymineralic segregations of pyrrhotite, chalcopyrite, cubanite, and pentlandite. Two types of sulfide solid solutions - iron-nickel (Mss) and iron-copper (Iss) - were found among sulfide globules. These types appear to have formed because of sulfide-sulfide liquid immiscibility in the host magmas; as proved by the presence of globules with a distinct phase boundary between Mss and Iss. Such two-phase globules are associated with large olivine phenocrysts. Inhomogeneties among the globule composition likewise are caused by sulfide-sulfide immiscibility. Secondary sulfides form irregular segregations and veins consisting of pyrite, marcasite, and chalcopyrite.

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From laboratory tests under simulated downhole conditions we tentatively conclude that the higher the triaxial-compressive strength, the lower the drilling rate of basalts from DSDP Hole 504B. Because strength is roughly proportional to Young's modulus of elasticity, which is related in turn to seismic-wave velocities, one may be able to estimate drilling rates from routine shipboard measurements. However, further research is needed to verify that P-wave velocity is a generally useful predictor of relative drilling rate.

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Two sites on the southern flank of the Costa Rica Rift were drilled on DSDP Legs 68 and 69, one on crust 3.9 m.y. old and the other on crust 5.9 m.y. old. The basement of the younger site is effectively cooled by the circulation of seawater. The basement of the older site has been sealed by sediment, and an interval in the uppermost 560 meters of basement recently reheated to temperatures of 60 to 120°C. Although the thickness of the sediments at the two sites is similar (150-240 m versus 270 m), the much rougher basement topography at the younger Site 505 produces occasional basement outcrops, through which 80 to 90% of the total heat loss apparently occurs by advection of warm seawater. This seawater has been heated only slightly, however; the temperature at the base of the sediments is only 9°C. Changes in its composition due to reaction with the basement basalts are negligible, as indicated by profiles of sediment pore water chemistry. Bacterial sulfate reduction in the sediments produces a decrease in SO4 (and Ca) and an increase in alkalinity (and Sr and NH3) as depth increases to an intermediate level, but at deeper levels these trends reverse, and all of these species plus Mg, K, Na, and chlorinity approach seawater values near basement. Si, however, is higher, and Li may be lower. At the older site, Site 501/504, where heat loss is entirely by conduction, the temperature at the sediment/basement contact is 59°C. Sediment pore water chemistry is heavily affected by reaction with the basaltic basement, as indicated by large decreases in d18O, Mg, alkalinity, Na, and K and an increase in Ca with increasing depth. The size of the changes in d18O, Mg, alkalinity, Ca, Sr, and SO4 varies laterally over 500 meters, indicating lateral gradients in pore water chemistry that are nearly as large as the vertical gradients. The lateral gradients are believed to result from similar lateral gradients in the composition of the basement formation water, which propagate upward through the sediments by diffusion. A model of the d18O profile suggests that the basement at Site 501/504 was sealed off from advection about 1 m.y. ago, so that reaction rates began to dominate the basement pore water chemistry. A limestone-chert diagenetic front began to move upward through the lower sediments less than 200,000 yr. ago.

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Physical properties of basalts from Deep Sea Drilling Project Sites 504 and 505, south of the Costa Rica Rift, including wet-bulk density, water content, sonic velocity, and thermal conductivity, were measured on board D/V Glomar Challenger during Legs 69 and 70. The mean wet-bulk density is 2.90±0.06 g/cm**3, porosity 5.0±2.2%, sonic velocity 5.75±0.30 km/s, and thermal conductivity 1.67±0.09 W/m°K. Basalts from this young ocean crust (5.9 m.y.) have relatively low porosity and consequently high density and sonic velocity, as compared to average DSDP basalts. Some systematic trends in depth variation of physical properties were found: down to Core 40 in Hole 504B, grain densities were lower than those deeper in the hole, whereas porosity in the upper section was higher. This can be attributed either to differences in the flow type or in the nature of alteration of basalts at the different levels in the hole.