Aspectos econômicos, ambientais e sociais da produção cafeeira em diferentes sistemas em Rondônia.

Este trabalho procurou avaliar o desempenho econômico, ambiental e social de diferentes sistemas de produção de café no estado de Rondônia. Foram selecionados cinco sistemas de produção de café em três importantes municípios produtores de café no estado de Rondônia: Alta Floresta, Cacoal e Nova Brasilândia.bitstream/CPAF-RO-2010/14572/1/351-cafeicultura.pd

Dirac-Surface-State-Dominated Spin to Charge Current Conversion in the Topological Insulator (Bi0.22Sb0.78)2Te3(Bi_{0.22}Sb_{0.78})_2Te_3 Films at Room Temperature

We report the spin to charge current conversation in an intrinsic topological insulator (TI) $(Bi_{0.22}Sb_{0.78})_2Te_3$ film at room temperature. The spin currents are generated in a thin layer of permalloy (Py) by two different processes, spin pumping (SPE) and spin Seebeck effects (SSE). In the first we use microwave-driven ferromagnetic resonance of the Py film to generate a SPE spin current that is injected into the TI $(Bi_{0.22}Sb_{0.78})_2Te_3$ layer in direct contact with Py. In the second we use the SSE in the longitudinal configuration in Py without contamination by the Nernst effect made possible with a thin NiO layer between the Py and $(Bi_{0.22}Sb_{0.78})_2Te_3$ layers. The spin-to-charge current conversion is attributed to the inverse Edelstein effect (IEE) made possible by the spin-momentum locking in the electron Fermi contours due to the Rashba field. The measurements by the two techniques yield very similar values for the IEE parameter, which are larger than the reported values in the previous studies on topological insulators.Comment: 18 pages and 7 figure

Characterization of phosphorus adsorption in soils of Rio Grande do Norte

Em amostras de solos representativos de duas microrregiões do Estado do Rio Grande do Norte, Bruno não cálcico, Podzólico, Latossolo, Litólico e Vertissolo, foram adicionadas doses crescentes de fósforo para avaliação de parâmetros de adsorção. Os dados obtidos foram plotados sob a forma da isoterma de Langmuir e apresentaram alta correlação linear para P solução de 0,7 a 11,9 x 10-4M, em solos de textura média a franco arenosa, e para valores superiores a 1 x 10-4M, em solos de textura argilosa. Das isotermas traçadas foram calculadas as respectivas equações e determinada a adsorção máxima, a adsorção estimada para um nível crítico de P solução igual a 0,1 ou 0,2 ppm, e a energia de retenção. Os valores mais baixos de adsorção máxima foram apresentados pelos solos Podzólico e Latossolo, em torno de 70 ppm, e o mais alto pelo Vertissolo, 1.075 ppm.In representative soils of two regions in Rio Grande do Norte State: Noncalcic Brown, Podzolic, Latosol, Lithosolic and Vertisol, phosphorus levels were added for determination of adsorption parameters. The values obtained were graphically represented in Langmuir isotherm form and showed high linear correlations for P-solutions between 0.7 and 11.9 x 10-4M, in soils of the sandy loam texture and to values higher than 1 x 10-4M in clayey soils. The Langmuir equations, maximum adsorption, estimated adsorption to phosphorus solutions at 0.1 or 0.2 ppm and bonding energy were to be determined. The Podzolic and Latosol soils showed the values of maximum adsorption, around 70 ppm. The highest value was showed in Vertisol soil, 1,075 ppm

Random magnetic fields inducing solar neutrino spin-flavor precession in a three generation context

We study the effect of random magnetic fields in the spin-flavor precession of solar neutrinos in a three generation context, when a non-vanishing transition magnetic moment is assumed. While this kind of precession is strongly constrained when the magnetic moment involves the first family, such constraints do not apply if we suppose a transition magnetic moment between the second and third families. In this scenario we can have a large non-electron anti-neutrino flux arriving on Earth, which can lead to some interesting phenomenological consequences, as, for instance, the suppression of day-night asymmetry. We have analyzed the high energy solar neutrino data and the KamLAND experiment to constrain the solar mixing angle, and solar mass difference, and we have found a larger shift of allowed values.Comment: 10 pages, 3 figure

Avaliação de cultivares de milho precoce em alguns estados do Nordeste brasileiro.

bitstream/item/88596/1/CPATC-PESQ.-AND.-27-84.pd

Minimal 3-3-1 model, lepton mixing and muonium-antimuonium conversion

The recent experimental results on neutrino oscillation and on muonium-antimuonium conversion require extension of the minimal 3-3-1 model. We review the constraints imposed to the model by those measurements and suggest a pattern of leptonic mixing, with charged leptons in a non-diagonal basis, which accounts for the neutrino physics and circumvents the tight muonium-antimuonium bounds on the model. We also illustrate a scenario where this pattern could be realized.Comment: 4 pages; abbreviated version, conclusions unchange

Ocorrência e cultivares de bananeiras preferenciais da broca-gigante (Castnia licus) em Rondônia.

Avaliou-se as cultivares de bananeiras existentes no Campo Experimental de Porto Velho, com o objetivo de verificar a infestação pela praga Castnia licus, ordinariamente chamada de broca-gigante.bitstream/item/42534/1/Cot292-bananeira.pd

Testing the cosmic distance duality with X-ray gas mass fraction and supernovae data

In this paper we discuss a new cosmological model-independent test for the cosmic distance duality relation (CDDR), $\eta = D_{L}(L)(1+z)^{-2}/D_{A}(z)=1$, where $D_{A}(z)$ and $D_{L}(z)$ are the angular and luminosity distances, respectively. Using the general expression for X-ray gas mass fraction ($f_{gas}$) of galaxy clusters, $f_{gas} \propto D_L{D_A}^{1/2}$, we show that $f_{gas}$ observations jointly with type Ia supernovae (SNe Ia) data furnish a validity test for the CDDR. To perform our analysis we use 38 $f_{gas}$ measurements recently studied by two groups considering different assumptions to describe the clusters (La Roque {\it{et al.}} 2006 and Ettori {\it{et al.}} 2009) and two subsamples of SNe Ia distance luminosity extracted from the Union2 compilation. In our test we consider the $\eta$ parameter as a function of the redshift parameterized by two different functional forms. It is found that the La Roque {\it{et al.}} (2006) sample is in perfect agreement with the duality relation ($\eta = 1$) whereas the Ettori {\it{et al.}} (2009) sample presents a significant conflict.Comment: 5 pages, 2 figures, 1 table, Letter to MNRAS (in press

Recomendacoes para a cultura do algodoeiro herbaceo irrigado no nordeste brasileiro.

bitstream/item/33381/1/RECOMENDACOES-PARA-A-CULTURA.pd