979 resultados para Belingwe Greenstone Belt


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Relatório de Estágio submetidoà Escola Superior de Teatro e Cinemapara cumprimento dos requisitos necessários à obtenção do grau de Mestre em Artes Performativas- especialização em Teatro-Música

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Genome-wide studies of African populations have the potential to reveal powerful insights into the evolution of our species, as these diverse populations have been exposed to intense selective pressures imposed by infectious diseases, diet, and environmental factors. Within Africa, the Sahel Belt extensively overlaps the geographical center of several endemic infections such as malaria, trypanosomiasis, meningitis, and hemorrhagic fevers. We screened 2.5 million single nucleotide polymorphisms in 161 individuals from 13 Sahelian populations, which together with published data cover Western, Central, and Eastern Sahel, and include both nomadic and sedentary groups. We confirmed the role of this Belt as a main corridor for human migrations across the continent. Strong admixture was observed in both Central and Eastern Sahelian populations, with North Africans and Near Eastern/Arabians, respectively, but it was inexistent in Western Sahelian populations. Genome-wide local ancestry inference in admixed Sahelian populations revealed several candidate regions that were significantly enriched for non-autochthonous haplotypes, and many showed to be under positive selection. The DARC gene region in Arabs and Nubians was enriched for African ancestry, whereas the RAB3GAP1/LCT/MCM6 region in Oromo, the TAS2R gene family in Fulani, and the ALMS1/NAT8 in Turkana and Samburu were enriched for non-African ancestry. Signals of positive selection varied in terms of geographic amplitude. Some genomic regions were selected across the Belt, the most striking example being the malaria-related DARC gene. Others were Western-specific (oxytocin, calcium, and heart pathways), Eastern-specific (lipid pathways), or even population-restricted (TAS2R genes in Fulani, which may reflect sexual selection).

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Este proyecto estudiará las estrategias de vida implementadas por familias productoras fruti hortícolas que viven en Colonia Tirolesa y Chacra de la Merced, lugares que forman parte del cinturón verde de la Ciudad de Córdoba; y su relación con los procesos de diferenciación social, asociados a cambios productivos, económicos, culturales y sociales que están condicionados por el modelo de expansión capitalista. A partir del análisis del capital económico, social, cultural y simbólico se identificará en un contexto rural las motivaciones, logicas productivas y conocimientos agrícolas que incidieron en las decisiones asumidas ante problematicas emergentes, tales como limitaciones para adquirir nuevos paquetes tecnológicos, el impacto ambiental causados por la no conservación y sustentabilidad de los recursos y las consecuencias sociales vinculadas a los laxos de familia, el trabajo y la calidad de vida.Se plantean las siguientes hipótesis: 1)Algunas familias productoras implementaron estrategias de vida que se relacionan con criterios de autosustentabilidad, conocimientos agrícolas tradicionales y pautas culturales.2) Los nuevos espacios productivos no son compatibles con agroecosistemas sustentables. 3) Las nuevas tecnologías causaron impactos en la actividad productiva e incidieron en la economía, calidad de vida y vinculos familiares. 4)El modo de producción familiar fue reemplazado por el modo de producción capitalista lo que incidió en la producción agrícola y en la conservación de los recursos.El objetivo principal es descubrir las estrategias de vida implementadas por un grupo de familias, trabajadoras fruti hortícolas, en respuesta a las transformaciones productivas, tecnológicas y socio económicas impuestas por el modelo de acumulación vigente.Para ello se caracterizará los ambitos productivos de trabajo a campo, identificando la disponibilidad de capital y los conocimientos técnicos y de manejo. También se analizarán las pautas y valores culturales, el impacto de las nuevas tecnologías y la incidencia social, vinculada a los cambios en los modos de producción.El abordaje será de tipo cualitativo, recavando información para elaborar una descripción detallada de las estrategias de vida adoptadas a partir de la década de los noventa. Se tomará como unidad de análisis a las familias que trabajaron o trabajan en la producción de hortalizas o frutales. Se realizarán combinaciones entre procedimientos Tipológicos a Priori; Históricos Comparativos y casos Unitarios. Se analizará las normativas vigentes en relación al uso y calidad del agua y del suelo; también imágenes satelitales para analizar los procesos de cambio en el uso del territorio y del recurso suelo. Se pretende realizar un aporte relacionado con el conocimiento de: la sustentabilidad de los sistemas productivos, la pobreza y los modos de vida de los productores fruti hortícolas que persistencia en ambientes degradados; en una franja intermedia entre el campo y la ciudad.

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White micas in carbonate-rich tectonites and a few other rock types of large thrusts in the Swiss Helvetic fold-and-thrust belt have been analyzed by Ar-40/Ar-39 and Rb/Sr techniques to better constrain the timing of Alpine deformation for this region. Incremental Ar-40/Ar-39 heating experiments of 25 weakly metamorphosed (anchizone to low greenschist) samples yield plateau and staircase spectra. We interpret most of the staircase release spectra result from variable mixtures of syntectonic (neoformed) and detrital micas. The range in dates obtained within individual spectra depends primarily on the duration of mica nucleation and growth, and relative proportions of neoformed and detrital mica. Rb/Sr analyses of 12 samples yield dates of ca. 10-39 Ma (excluding one anomalously young sample). These dates are slightly younger than the Ar-40/Ar-39 total gas dates obtained for the same samples. The Rb/ Sr dates were calculated using initial Sr-87/Sr-86 ratios obtained from the carbonate-dominated host rocks, which are higher than normal Mesozoic carbonate values due to exchange with fluids of higher Sr-87/Sr-86 ratios (and lower O-18/O-16 ratios). Model dates calculated using Sr-87/Sr-86 values typical of Mesozoic marine carbonates more closely approximate the Ar-40/Ar-39 total gas dates for most of the samples. The similarities of Rb/Sr and Ar-40/Ar-39 total gas dates are consistent with limited amounts of detrital mica in the samples. The delta(18)O values range from 24-15%. (VSMOW) for 2-6 mum micas and 27-16parts per thousand for the carbonate host rocks. The carbonate values are significantly lower than their protolith values due to localized fluid-rock interaction and fluid flow along most thrust surfaces. Although most calcite-mica pairs are not in oxygen isotope equilibrium at temperatures of ca. 200-400 degreesC, their isotopic fractionations are indicative of either 1) partial exchange between the minerals and a common external fluid, or 2) growth or isotopic exchange of the mica with the carbonate after the carbonate had isotopically exchanged with an external fluid. The geological significance of these results is not easily or uniquely determined, and exemplifies the difficulties inherent in dating very fine-grained micas of highly deformed tectonites in low-grade metamorphic terranes. Two generalizations can be made regarding the dates obtained from the Helvetic thrusts: 1) samples from the two highest thrusts (Mt. Gond and Sublage) have all of their Ar-40/Ar-39 steps above 20 Ma, and 2) most samples from the deepest Helvetic thrusts have steps (often accounting for more than 80% of Ar-39 release) between 15 and 25 Ma. These dates are consistent with the order of thrusting in the foreland-imbricating system and increase proportions of neoformed to detrital mica in the more metamorphosed hinterland and deeply buried portions of the nappe pile. Individual thrusts accommodated the majority of their displacement during their initial incorporation into the foreland-imbricating system, and some thrusts remained active or were reactivated down to 15 Ma.

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In the southwestern part of the Aiguilles Rouges massif (pre-Alpine basement of the Helvetic realm, western Alps), a metavolcanic sequence, newly defined as the ``Greenstone Unit'',is exposed in two NS trending belts of several 100 metres in thickness. It consists of epidote amphibolites, partly epidote and/or calcic amphibole-bearing greenschists, and small amounts of alkali feldspar-bearing greenschists, which underwent low- to medium-grade metamorphism during Visean oblique collision. Metamorphic calcic amphiboles and epidotes show strong chemical zoning, whereas metamorphic plagioclase is exclusively albitic in composition (An 1-3). The SiO2 content of the subalkaline tholeiitic to calc-alkaline suite ranges continuously from 44 wt% to 73 wt%,but andesitic rocks predominate. The majority of samples have chemical compositions close to recent subduction-related lavas; some are even restricted to recent oceanic arcs (extremely low Ta and Nb contents, high La/Nb and Th/Ta ratios). But several basaltic to basalto-andesitic samples resemble continental tholeiites (low Th/Ta, La/Nb ratio). As it is very probable that both lava types are to some extent contemporaneous, it is proposed that the Greenstone Unit represents a former oceanic volcanic are which temporarily underwent extension during which emplacement of continental tholeiite-like rocks occurred. The cause of the extension remains ambiguous. Considering palaeotectonic significance and age of other metavolcanic units in the Aiguilles Rouges massif, the Greenstone Unit most likely formed in the Early Palaeozoic.

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The Western Alpine Are has been created during the Cretaceous and the Tertiary orogenies. The interference patterns of the Tertiary structures suggest their formation during continental collision of the European and the Adriatic Plates, with an accompanying anticlockwise rotation of the Adriatic indenter. Extensional structures are mainly related to ductile deformation by simple shear. These structures developed at a deep tectonic level, in granitic crustal rocks, at depths in excess of 10 km. In the early Palaeogene period of the Tertiary Orogeny, the main Tertiary nappe emplacement resulted from a NW-thrusting of the Austroalpine, Penninic and Helvetic nappes. Heating of the deep zone of the Upper Cretaceous and Tertiary nappe stack by geothermal heat flow is responsible for the Tertiary regional metamorphism, reaching amphibolite-facies conditions in the Lepontine Gneiss Dome (geothermal gradient 25 degrees C/ km). The Tertiary thrusting occurred mainly during prograde metamorphic conditions with creation of a penetrative NW-SE-oriented stretching lineation, X(1) (finite extension), parallel to the direction of simple shear. Earliest cooling after the culmination of the Tertiary metamorphism, some 38 Ma ago, is recorded by the cooling curves of the Monte Rosa and Mischabel nappes to the west and the Suretta Nappe to the east of the Lepontine Gneiss Dome. The onset of dextral transpression, with a strong extension parallel to the mountain belt, and the oldest S-vergent `'backfolding'' took place some 35 to 30 Ma ago during retrograde amphibolite-facies conditions and before the intrusion of the Oligocene dikes north of the Periadriatic Line. The main updoming of the Lepontine Gneiss Dome started some 32-30 Ma ago with the intrusion of the Bergell tonalites and granodiorites, concomitant with S-vergent backfolding and backthrusting and dextral strike-slip movements along the Tonale and Canavese Lines (Argand's Insubric phase). Subsequently, the center of main updoming migrated slowly to the west, reaching the Simplon region some 20 Ma ago. This was contemporaneous with the westward migration of the Adriatic indenter. Between 20 Ma and the present, the Western Aar Massif-Toce culmination was the center of strong uplift. The youngest S-vergent backfolds, the Glishorn anticline and the Berisal syncline fold the 12 Ma Rb/Sr biotite isochron and are cut by the 11 Ma old Rhone-Simplon Line. The discrete Rhone-Simplon Line represents a late retrograde manifestation in the preexisting ductile Simplon Shear Zone. This fault zone is still active today. The Oligocene-Neogene dextral transpression and extension in the Simplon area were concurrent with thrusting to the northwest of the Helvetic nappes, the Prealpes (35-15 Ma) and with the Jura thin-skinned thrust (11-3 Ma). It was also contemporaneous with thrusting to the south of the Bergamasc (> 35-5 Ma) and Milan thrusts (16-5 Ma).

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Deformation of the Circum-Rhodope Belt Mesozoic (Middle Triassic to earliest Lower Cretaceous) low-grade schists underneath an arc-related ophiolitic magmatic suite and associated sedimentary successions in the eastern Rhodope-Thrace region occurred as a two-episode tectonic process: (i) Late Jurassic deformation of arc to margin units resulting from the eastern Rhodope-Evros arc-Rhodope terrane continental margin collision and accretion to that margin, and (ii) Middle Eocene deformation related to the Tertiary crustal extension and final collision resulting in the closure of the Vardar ocean south of the Rhodope terrane. The first deformational event D-1 is expressed by Late Jurassic NW-N vergent fold generations and the main and subsidiary planar-linear structures. Although overprinting, these structural elements depict uniform bulk north-directed thrust kinematics and are geometrically compatible with the increments of progressive deformation that develops in same greenschist-facies metamorphic grade. It followed the Early-Middle Jurassic magmatic evolution of the eastern Rhodope-Evros arc established on the upper plate of the southward subducting Maliac-Meliata oceanic lithosphere that established the Vardar Ocean in a supra-subduction back-arc setting. This first event resulted in the thrust-related tectonic emplacement of the Mesozoic schists in a supra-crustal level onto the Rhodope continental margin. This Late Jurassic-Early Cretaceous tectonic event related to N-vergent Balkan orogeny is well-constrained by geochronological data and traced at a regional-scale within distinct units of the Carpatho-Balkan Belt. Following subduction reversal towards the north whereby the Vardar Ocean was subducted beneath the Rhodope margin by latest Cretaceous times, the low-grade schists aquired a new position in the upper plate, and hence, the Mesozoic schists are lacking the Cretaceous S-directed tectono-metamorphic episode whose effects are widespread in the underlying high-grade basement. The subduction of the remnant Vardar Ocean located behind the colliding arc since the middle Cretaceous was responsible for its ultimate closure, Early Tertiary collision with the Pelagonian block and extension in the region caused the extensional collapse related to the second deformational event D-2. This extensional episode was experienced passively by the Mesozoic schists located in the hanging wall of the extensional detachments in Eocene times. It resulted in NE-SW oriented open folds representing corrugation antiforms of the extensional detachment surfaces, brittle faulting and burial history beneath thick Eocene sediments as indicated by 42.1-39.7 Ma Ar-40/Ar-39 mica plateau ages obtained in the study. The results provide structural constraints for the involvement components of Jurassic paleo-subduction zone in a Late Jurassic arc-continental margin collisional history that contributed to accretion-related crustal growth of the Rhodope terrane. (C) 2011 Elsevier Ltd. All rights reserved.

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Iowa has two seat belt laws, which have been amended several times since the original law took eff ect July 1, 1986. The most recent changes, effective July 1, 2010, were made during the 2010 legislative session by Senate File 2381.

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This brochure explains Iowa's seat belt laws

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A new genus (Triassiphaeodina gen. nov.) and two new species (Medusetta japonica sp. nov. and Triassiphaeodina niyodoensis sp. nov.) of Late Triassic (Rhaetian) phaeodarian Radiolaria are described from a phosphatic nodule found in melange rocks of the Northern Chichibu Belt, Shikoku, Japan. The Rhaetian age of the nodule and of the phaeodarian new taxa is based on co-occurring Polycystina Radiolaria, including Bipedis acrostylus Bragin, Livarella densiporata Kozur and Mostler, Fontinella primitiva Carter, and Ferresium sp. A of Carter (1993). This finding shows that phaeodarian Radiolaria were already represented in Late Triassic oceans, with morphologies similar to those known in the Late Cretaceous and Cenozoic, from which they have previously been reported. The new taxa described herein represent the oldest known phaeodarian fossils.

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This report presents the results of a literature review conducted to evaluate differences in seat belt use by race. A literature review was conducted to evaluate overall seat belt use, racial differences in seat belt use, overall child restraint use, racial differences in child restraint use, and information about seat belt and child restraint use specific to Iowa. A number of national studies and regional studies were found and are presented. Mixed results were found as to whether racial differences exist in both seat belt use and child restraint use. However, in the course of the literature review, several items that are of interest to safety in Iowa have emerged, although little data specific to Iowa was encountered. First, national seat belt use appears to be lower among African-Americans than for Caucasians or Hispanics. Second, national crash rates among Hispanics appear to be higher than those for Caucasians, particularly when population and lower vehicle miles traveled (VMT) are considered. One issue that should be considered throughout this literature review is that the Hispanic population may be higher than reported due to large numbers of undocumented persons who do not appear in population estimates, driver’s license, or other databases.

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This analysis examined data from a variety of sources to estimate the benefit of enhancing Iowa’s current law to require all passengers to use seat belts. In addition to assessing Iowans’ opinions about changing the law, a literature review, a legislative policy review, and analysis of Iowa crash data were completed. Currently 28 states enforce seat belt laws for all passengers. Belted passengers riding with an unbelted passenger are 2 to 5 times more likely to suffer fatal injuries in a crash relative to when all occupants are using seat belts. Iowans are highly compliant (90%-94%) with the current seat belt law for front seat occupants. Of more than 1000 Iowans surveyed, 85% said they always use a seat belt when riding in the front seat, but only 36% always do so when they ride in the back seat. The most common reasons given for not using seat belts in the back seat are forgetting to buckle up and because it is not the law. Iowans widely support strengthening Iowa’s seat belt law — 62% said Iowa law should require all rear seat passengers to use seat belts. Four out of five respondents said they would use seat belts more often when sitting in the rear seat if it was the law. It is estimated rear seat fatalities would decrease about 48%, from 13 to 7 fatalities annually, if an all-passenger law was implemented in Iowa.

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Usingof belt for high precision applications has become appropriate because of the rapid development in motor and drive technology as well as the implementation of timing belts in servo systems. Belt drive systems provide highspeed and acceleration, accurate and repeatable motion with high efficiency, long stroke lengths and low cost. Modeling of a linear belt-drive system and designing its position control are examined in this work. Friction phenomena and position dependent elasticity of the belt are analyzed. Computer simulated results show that the developed model is adequate. The PID control for accurate tracking control and accurate position control is designed and applied to the real test setup. Both the simulation and the experimental results demonstrate that the designed controller meets the specified performance specifications.