851 resultados para rock forming
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A few examples of supergene ore formation and their interaction with morphogenesis (palaeosurfaces) and weathering mineralogy are discussed. Geomorphological and mineralogical records to characterize palaeosurfaces associate the weathering of primary minerals and their relationship with concentrations of cooper and iron ore deposits in southeastern state of São Paulo, Brazil. We have distinguished two palaeosurfaces generated by several weathering phases and controlled by the geological framework. The first and oldest upper palaeosurfaces (900 - 1000 m a.s.l.), situated in Riberão Branco (Alto do Brancal), were developed on silico-limestones. It is formed by typical iron laterites enriched by secondary products of cooper. The second and younger level palaeosurfaces located in Itapeva (Santa Blandina and Bairro do Sambra). This palaeosurface is formed by copper percolating through the weathered rock (saprolite). Other features can be observed like neo-formed products in laterites. They are classified into two types: clay like silico- cupriferous products (with noticeable amounts of iron) and copper minerals (crysocolla, in their flat slopes). These features allowed the presence of copper ores and their morphogenesis control will help in the exploration and prospecting of supergene ore mineral.
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The objectives of this work were to study the suitability and highlight the advantages of the use of cross-linked ureasil-polyether hybrid matrices as film-forming systems. The results revealed that ureasil-polyethers are excellent film-forming systems due to specific properties, such as their biocompatibility, their cosmetic attractiveness for being able to form thin and transparent films, their short drying time to form films and their excellent bioadhesion compared to the commercial products known as strong adhesives. Rheological measurements have demonstrated the ability of these hybrid matrices to form a film in only a few seconds and Water Vapor Transmitting Rate (WVTR) showed adequate semi-occlusive properties suggesting that these films could be used as skin and wound protectors. Both the high skin bioadhesion and non-cytotoxic character seems to be improved by the presence of multiple amine groups in the hybrid molecules. © 2012 Elsevier B.V.
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We studied the vegetation of two crystalline rock outcrops in the Atlantic Forest of northeastern Brazil. We recorded typically rupicolous species, which are rare or classified as extremely endangered, such as Aechmea guainumbiorum, found exclusively in one of the study sites. In both areas there was a predominance of therophytes over other life-forms, in contrast to observations made in rock outcrops of the southern Atlantic Forest. Therophytes also stood out in other rock outcrops at similar latitudes as our study site, regardless of the surrounding vegetation. Plants of other life-forms had significantly lower richness and showed adaptations to drought, such as succulent stem, pseudobulbs, dense pilosity, and underground storage organs. Our results suggest that invasive species may modify the vegetation of crystalline rock outcrops, as they change the number of species of all life-forms in comparison between sites. Hence, our results present the biological identity of these rupicolous habitats, which are marginal to forests, and point to the need for conserving them, in order to protect the Atlantic Forest's biodiversity. © 2013 Botanical Society of Sao Paulo.
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The movement patterns of males, females and juveniles of lekking species often differ due to differences in the commitment to lek activities, which may lead to differences in the spatial distribution and dispersal distances of seeds they eat. By sampling seeds in three lek and non-lek areas of the white-bearded manakin (Manacus manacus), we tested whether this lekking species increased the abundance and species richness of seeds in lek areas and, at a finer scale, in 21 displaying courts within lek areas. Combining data on seed defecation or regurgitation rates by free-ranging individuals, the number of seeds in droppings or regurgitations of mist-netted birds, and the distances travelled by birds equipped with radio-transmitters, we estimated the potential spatial distribution of seeds generated by six resident males and six females or juveniles during the morning peak of lek activity and when lek activity decreased in the afternoon. There was no difference in the species richness (46 and 44 morphospecies, respectively) and abundance of seeds (15.4 ± 7.3 seeds and 14.0 ± 1.1 seeds, respectively) between lek and non-lek areas. Within leks both parameters increased in courts (45 spp., 17.6 ± 14 seeds) compared with non-court sites (22 spp., 1.9 ± 1.8 seeds), likely as a consequence of the longer time spent by resident males in perches in or near display courts. Distances moved by juveniles and females per 60-min period (183 ± 272 m) were greater than resident males (42.6 ± 22.0 m) in the mornings, while the opposite happened in the afternoons (55.2 ± 40.7 m and 157 ± 105 m, respectively). We conclude that the spatial aggregation of seeds in lek areas of M. manacus occurs at the court level, and the spatial distribution of deposited seeds varies with manakin lekking status and the daily period of foraging. © Cambridge University Press 2013.
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Pós-graduação em Ciências Sociais - FFC
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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A literatura contemporânea expressa o rompimento das fronteiras entre a cultura erudita e a cultura de massa ou comercial, criando formas híbridas que convivem no interior do texto. No romance Voyages de l’autre cote (1975), de Jean-Marie Gustave Le Clézio, as canções do pop rock embalam as viagens da fada Naja Naja e de seus amigos em busca do ‘outro lado’. Desta forma, a impregnação da música popular à escritura poética, parece ajudar a libertar a imaginação, preparando as personagens para o encontro do infinito sensível.