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

A Simple Realization of the Inverse Seesaw Mechanism

Differently from the canonical seesaw mechanism, which is grounded in grand unified theories, the inverse seesaw mechanism lacks a special framework that realizes it naturally. In this work we advocate that the 3-3-1 model with right-handed neutrinos has such an appropriate framework to accommodate the inverse seesaw mechanism. We also provide an explanation for the smallness of the $\mu$ parameter and estimate the branching ratio for the rare lepton flavor violation process $\mu \rightarrow e\gamma$.Comment: About 14pages, no figures, basis corrected, to appear at the PR

Combining type I and type II seesaw mechanisms in the minimal 3-3-1 model

The minimal 3-3-1 model is perturbative until energies around 4-5TeV, posing a challenge to generate neutrino masses at eV scale, mainly if one aims to take advantage of the seesaw mechanism. As a means to circumvent this problem we propose a modification of the model such that it accommodates the type I and type II seesaw mechanisms altogether. We show that the conjunction of both mechanisms yield a neutrino mass expression suppressed by a high power of the cutoff scale, $M^5$, in its denominator. With such a suppression term we naturally obtain neutrino masses at eV scale when $M$ is around few TeV. We also investigate the size of lepton flavor violation through the process $\mu \rightarrow e\gamma$.Comment: about 15 pages, no figure

Effect of commercial mannoproteins on wine colour and tannins stability

Available at ScienceDirectCommercial oenological products containing mannoproteins have the purpose of preventing tartrate salts precipitation or achieving wines with a better mouth-feeling. The evaluation of the influence of three commercial mannoproteins on colour and tannin stability of three different red wines (two from Touriga Nacional and one from Alfrocheiro and Aragonês varieties) was studied. The evolution of colour through time was similar for all modalities, resulting in an increase of polymeric pigments and colour hue and a decrease of other parameters, suggesting that there was no influence of commercial mannoproteins on colour stability. The tannin profile evolution showed a possible stabilizing effect of one of the commercial products for tannins with an mDP between 8 and 14. It is possible that the commercial mannoproteins used in this work have some influence on the tannin aggregation evolution, contributing to the delay of tannin polymerisation in red wines

Avaliação da produtividade das cultivares de Oryza sativa nas entrelinhas da palma de óleo (Elaeis guineenses) - Tailândia-PA.

O presente trabalho teve como objetivo analisar a produção das cultivares de arroz (BRS Monarca e BRS Pepita) quando consorciado com a palma de óleo (Dendê) em área de agricultor familiar situado no município de Tailândia. Foram realizadas avaliações periódicas quinzenais durante o cultivo, colheita e pós-colheita, obtendo resultados favoráveis ao consórcio com as produtividades de 3.490Kg/ha e 3.245g/ha, para Monarca e Pepita respectivamente.PIBIC 2013