12,543 research outputs found
Spin-polarized transport in ferromagnetic multilayered semiconductor nanostructures
The occurrence of inhomogeneous spin-density distribution in multilayered
ferromagnetic diluted magnetic semiconductor nanostructures leads to strong
dependence of the spin-polarized transport properties on these systems. The
spin-dependent mobility, conductivity and resistivity in
(Ga,Mn)As/GaAs,(Ga,Mn)N/GaN, and (Si,Mn)/Si multilayers are calculated as a
function of temperature, scaled by the average magnetization of the diluted
magnetic semiconductor layers. An increase of the resistivity near the
transition temperature is obtained. We observed that the spin-polarized
transport properties changes strongly among the three materials.Comment: 3 pages, 4 figure
Estudo da morfologia funcional do estômago e do hábito alimentar do camarão Pitu (Macrobrachium carcinus) (Linnaeus, 1758) (crustacea, decapoda, palaemonidae) na Foz do Rio Amazonas.
Resumo simples
Natural diet and feeding habits of a freshwater prawn (Macrobrachium carcinus: Crustacea, Decapoda) in the estuary of the Amazon River.
Macrobrachium carcinus is a Brazilian native prawn with recognized potential for use in aquaculture activities. However, there is little information about the natural diet and feeding habits of this species. The aim of this study was the identification of the diet items of M. carcinus based on the analysis of the stomach contents. Specimens were collected in the Amazon River estuary between January 2009 and January 2010. The stomach analysis was carried out by using the frequency of occurrence (FO), methods of points (MP) and feeding index (FI). It was observed that prawns fed on detritus, animals and plant fragments as the most important food items. Sediment accounted for the main stomach content, accounting for 43.2% by the MP, 44.9% by FI and 100% by the FO. Sexual differences in feeding preferences were not found in this study, and seasonal differences in the frequency of items ingested by M. carcinus were not observed. The results indicated that M. carcinus can be considered omnivorous species, but with an important carnivorous component, similar to that found in other Macrobrachium species
Relação peso-comprimento do camarão pitú, Macrobrachium carcinus (Crustacea, Decapoda, Palaemonidae) na foz do rio Amazonas.
Resumo simples
Caracterização agronômica e fitoquímica e estudo da variabilidade genética de acessos de Piper do Banco Ativo de Germoplasma da Embrapa Acre.
Dieta natural de Armases benedicti Rathbun, 1897 (Brachyura, Sersamidae) na foz do Rio Amazonas.
Avaliação preliminar de genótipos de mandioca em solos sob vegetação de cerrados do Piauí.
Este trabalho tem como objetivos principais: introduzir e selecionar genotipos de mandioca em diferentes mesorregioes, com alto potencial produtivo, associados a elevada percentagem de amido nas raizes para serem recomendados aos produtores de farinha, goma ou tapioca; identificar genotipos com alto potencial de producao de parte aerea, visando sua utilizacao na alimentacao animal.bitstream/item/97589/1/PAND860001.pd
- …