Rare Lands
Mostrando 1-4 de 4 artigos, teses e dissertações.
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1. The rarest of the rare: rediscovery and status of the critically endangered Belem Curassow, Crax fasciolata pinima (Pelzeln, 1870)
Abstract The Belem Curassow (Crax fasciolata pinima) is one of the most endangered birds in South America, without sightings of birds in the wild for 40 years. This subspecies is nationally and internationally classified as critically endangered and close to extinction, suffering from poaching and deforestation in its range. Here we present new records of fr
Pap. Avulsos Zool.. Publicado em: 21/10/2019
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2. A beiradeira e o grilador: ocupação no oeste do Pará / The beiradeiraand the grilador: ocupation and conflict in West Pará
Like so many other Amazonian extractivists, the populations of Montanha and Mangabal trace their beginnings back to the first rubber cycle in the mid XIXth century when some of their ancestors installed themselves along the banks of the Upper Tapajos. Since then they have survived the debt bondage of the river trading system, the uncertain times that followe
Publicado em: 2008
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3. DEVELOPMENT OF A METHODOLOGY FOR THE SEPARATION OF EUROPIUM AND SAMARIUM FROM A MIXTURE OF RARE EARTH OXIDES BY ELECTROREDUCTION/PRECIPITATION / "Desenvolvimento de uma metodologia para a separação de Samário e Európio a partir de mistura de óxidos de Terras Raras por redução eletroquímica/ precipitação"
The rare earths (RE) were first used in 1903, when Welsbach developed a lighter that is still used today. Nowadays, the RE are employed in many different fields, as in the production of super-alloys , as catalysts for petroleum industry, in the manufacture of non-ferrous alloys, color television tubes, x-ray screens, special glasses, ceramics, computer indus
Publicado em: 2006
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4. ESTUDOS DOS PROCESSOS DE TRANSFERÊNCIA DE ENERGIA DOS ÍONS DE Er3+ E Ho3+ PARA OS ÍONS DE Nd3+, Tb3+ E Eu3+ NO CRISTAL DE LiYF4 E NO VIDRO ZBLAN PARA A OTIMIZAÇÃO DE MEIOS LASER ATIVOS QUE OPERAM NA REGIÃO DE 3 µm / STUDIES OF THE ENERGY TRANSFER PROCESSES FROM Er3+ AND Ho3+ TO Nd3+, Tb3+ OR Eu3+ IN LiYF4 CRYSTAL AND ZBLAN GLASS FOR THE LASER MEDIA OPTIMIZATION OPERATING NEAR 3µ m REGION
Foram estudados os processos de transferência de energia (TE) dos níveis 4I13/2 ; 4I11/2 do Er3+ e 5I7 ; 5I6 do Ho3+ no LiYF4 (YLF) e no ZBLAN, para os íons desativadores Nd3+, Tb3+ ou Eu3+. Os microparâmetros de interação dessas TE foram obtidos utilizandose o método da integral de sobreposição e os resultados indicaram que o íon de Eu3+ é o melh
Publicado em: 2006