Ferromagnetic tunneling junctions at low voltages: elastic versus inelastic scattering at T=0KT=0 K

In this paper we analyze different contributions to the magnetoresistance of magnetic tunneling junctions at low voltages. A substantial fraction of the resistance drop with voltage can be ascribed to variations of the density of states and the barrier transmission with the bias. However, we found that the anomaly observed at zero bias and the magnetoresistance behavior at very small voltages, point to the contribution of inelastic magnon-assisted tunneling. The latter is described by a transfer parameter $T^{J}$, which is one or two orders of magnitude smaller than $T^{d}$, the direct transmission for elastic currents. Our theory is in excellent agreement with experimental data, yielding estimated values of $T^{J}$ which are of the order of $T^{d}$ / $T^{J}$ ~ 40.Comment: 13 pages, 4 figures (in postscript format). PACS numbers: 72.25.-b, 73.23.-b, 72.10.D

Glucagon-producing cells are increased in Mas-deficient mice

It has been shown that Angiotensin-(1-7) [Ang-(1-7)] produces several effects related to glucose homeostasis. In this study, we aimed to investigate the effects of genetic deletion of Ang-(1-7), the GPCR Mas, on the glucagon -producing cells. C57BL6/N Mas-/- mice presented a significant and marked increase in pancreatic {alpha}-cells (number of cells: 146 +/- 21 vs. 67 +/- 8 in WT - p<0.001) and the percentage per islet (17.9±0.91 vs. 12.3 +/- 0.9% in WT - p<0.0001) with subsequent reduction of {beta}-cells percentage (82.1 +/- 0.91 vs. 87.7 +/- 0.9% in WT - p<0.0001). Accordingly, glucagon plasma levels were increased (516.7 +/- 36.35 vs 390.8 +/- 56.45 pg/mL in WT, p<0.05 ) and insulin plasma levels were decreased in C57BL6/N Mas-/- mice (0.25 +/- 0.01 vs 0.31 +/- 56.45 pg/mL in WT- p=0.02). In order to eliminate the possibility of a background-related phenotype we determined the number of glucagon-producing cells in FVB/N Mas-/- mice. In keeping with the observations in C57BL6/N Mas-/- mice, the number and percentage of pancreatic {alpha}-cells were also significantly increased in these mice (number of {alpha}-cells: 260 +/- 22 vs. 156 +/- 12 in WT, p<0.001; percentage per islet: 16 +/- 0.8 vs. 10 +/- 0.5% in WT, p<0.0001). These results suggest that Mas has a previously unexpected role on the pancreatic glucagon production

Aspectos da nutrição relacionados com a criação de suínos em fase de creche, crescimento e terminação em granjas do Sul do Brasil.

bitstream/item/58287/1/CUsersPiazzonDocuments288.pd

Spin-dependent resonant quantum tunneling between magnetic nanoparticles on a macroscopic length scale

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Macroscopic quantum phenomena are common features observed in superconductors, superfluid helium, and Bose-Einstein condensates. However, most of quantum transport studies are based on a small number of dots and are not in long-range electron transport length scale. Here we show that spin-dependent resonant quantum tunneling is achieved in the macroscopic length scale (a few millimeters) corresponding to an array of up to 10(4) junctions in a series consisting of Co nanoparticles embedded in an oxygen-deficient TiO(2) matrix. This phenomenon is observed by magnetoresistance measurements at 5 K in a Coulomb blockade regime. We further present a model based on resonant spin-polarized quantum tunneling of electrons of Co particles. It occurs through resonant continuous spin-polarized defect band states located near the Fermi level of the defective TiO(2), which acts as a magnetic tunnel barrier. These results might be potentially useful for future designs of spintronic quantum devices.834Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Promoção do crescimento de milho por novas estirpes de bactérias associativas: resultados de ensaios em rede conduzidos pelo instituto nacional de ciência e tecnologia da Fixação Biológica do Nitrogênio (INCT-FBN).

Foi implementada uma rede de ensaios pelo Instituto Nacional de Ciência e Tecnologia da Fixação Biológica do Nitrogênio (INCT-FBN) para a validação de novas estirpes de bactérias associativas com capacidade de promover o crescimento vegetal. A rede de ensaios formada abrange cinco estações experimentais, sendo quatro localizadas no Estado do Paraná e uma em Goiás.Editores técnicos: Mariangela Hungria, Fábio Martins Mercante. RELARE 2014