823 resultados para 985


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O presente trabalho propõe-se a analisar a efetividade das políticas públicas de criação de unidades de conservação sob a ótica dos mecanismos de regularização fundiária de que dispõe a Lei n 9.985/00, primordiais para o alcance dos objetivos preconizados pelo Sistema Nacional de Unidades de Conservação (SNUC), sobretudo no que diz respeito às unidades de conservação de proteção integral. Para tanto, inicia-se por situar a discussão, abordando como o meio ambiente, os espaços territoriais especialmente protegidos, a propriedade e a moradia são temas que se entrelaçam no ordenamento jurídico brasileiro. Em seguida, foca-se na análise da função socioambiental da propriedade enquanto fundamento das políticas públicas de criação de espaços territoriais especialmente protegidos. Continua com a abordagem de tais espaços segundo a legislação em vigor, em particular das unidades de conservação. Concluída tal exposição, o presente trabalho adentra seu cerne, dissecando aspectos relevantes dos mecanismos dispostos pela Lei n 9.985/00 para a regularização fundiária de unidades de conservação. Assim, com base no estudo do tema, almeja confirmar a hipótese de que tais mecanismos são imprescindíveis à efetividade das políticas públicas de criação de unidades de conservação, sugerindo, tanto quanto possível, alternativas à aplicação da norma para fins de contribuir com a efetividade do SNUC.

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Under short pulse laser excitation, we have observed an extra high-energy photoluminescence (PL) emission from GaNAs/GaAs single quantum wells (QWs). It dominates the PL spectra under high excitation and/or at high temperature. By measuring the PL dependence on both temperature and excitation power and by analyzing the time-resolved PL results, we have attributed the PL peak to the recombination of delocalized excitons in QWs. Furthermore, a competition process between localized and delocalized excitons is observed in the temperature-dependent PL spectra under the short pulse excitation. This competition is believed to be responsible for the temperature-induced S-shaped PL shift often observed in the disordered alloy semiconductor system under continuous-wave excitation. (C) 2001 American Institute of Physics.

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Photoluminescence from a GaN0.015As0.985/GaAs quantum well has been measured at 15 K under hydrostatic pressure up to 9 GPa. Both the emissions from the GaNAs well and GaAs barrier are observed. The GaNAs-related peak shows a much weaker pressure dependence compared to that of the GaAs band gap. A group of new peaks appear in the spectra when the pressure is beyond 2.5 GPa, which is attributed to the emissions from the N isoelectronic traps in GaAs. The pressure dependence of the GaNAs-related peaks was calculated using the two-level model with the measured pressure coefficients of the GaAs band gap and N level as fitting parameters. It is found that the calculated results deviate seriously from the experimental data. An increasing of the emission intensity and the linewidth of the GaNAs-related peaks was also observed and briefly discussed. (C) 2001 American Institute of Physics.

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Firmado por don Raúl Prebisch, Director Principal a cargo, y el Sr. Ministro de Relaciones Exteriores Guillermo del Pedregal

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The Cenozoic volcanic activity on Iceland has been recorded in North Atlantic sediments drilled during several Ocean Drilling Program (ODP)/Deep Sea Drilling Project legs (Legs 104, 151, 152, 162, and 163). Leg 162 (North Atlantic-Arctic Gateways II) recovered ash layers at Sites 982, 985, and 907 (Jansen, Raymo, Blum, et al., 1996, doi:10.2973/odp.proc.ir.162.1996). The revisited Site 907 was first drilled during Leg 151, and the ash from this site has been described in detail by Lacasse et al. (1996, doi:10.2973/odp.proc.sr.151.122.1996) and Werner et al. (1996, doi:10.2973/odp.proc.sr.151.123.1996). Site 982 is located within the Hatton-Rockall Basin on the Rockall Plateau, which is situated west of the British Isles. Site 985 is located northeast of Iceland at the foot of the eastern slope of the Iceland Plateau, adjacent to the Norwegian Basin. Here we report chemical analyses of Neogene tephra layers from Holes 982A, 983B, 982C, 985A, and 985B. The sedimentary sequence at Site 982 spans the lower Miocene-Holocene; Site 985 recovered sediments spanning the upper Oligocene-Holocene. Twenty-two distinct ash layers and ash-bearing sediments were sampled in Holes 982A-982C (Cores 162-982A-16H through 24H, 162-982B-14H through 56X, and 162-982C-15H through 27H), and 59 ash layers were sampled in Holes 985A and 985B (Cores 162-985A-11H through 59X, and 162-985B-11H through 14H). Almost 50% of the sampled ash is strongly altered (predominantly from Site 985). A cluster of altered thin layers in the lower Pliocene of Site 985 (top of Unit III) is remarkable.