Aircraft systems architecting: a functional-logical domain perspective

Presented is a novel framework for early systems architecture design. The framework defines data structures and algorithms that enable the systems architect to operate interactively and simultaneously in both the functional and logical domains. A prototype software tool, called AirCADia Architect, was implemented, which allowed the framework to be evaluated by practicing aircraft systems architects. The evaluation confirmed that, on the whole, the approach enables the architects to effectively express their creative ideas when synthesizing new architectures while still retaining control over the process

Parametrização de um modelo para estimativa da produtividade de soja para as regiões sul e centro-oeste do Brasil.

A produtividade de qualquer cultivo agrícola é resultado da interação genótipo e ambiente. No Brasil, cerca de 95% das indenizações pagas pelos instrumentos públicos de seguridade agrícola do Brasil estão relacionados à seca ou aos eventos de à chuva em excesso, mostrando sua importância. Na cultura de soja há dois períodos críticos no caso de déficit hídrico: da semeadura à emergência e no enchimento dos grãos. Em se tratando de um país como o Brasil cuja dimensão é continental e o cultivo de soja é nacional, a utilização de modelos que permitam obter estimativas confiáveis, rápidas e que necessitem de poucos dados operacionais são essenciais para seu gerenciamento. Usando o Modelo da Zona Agroecológica (MZA) foi feita a estimativa da produtividade de soja, a fim de se utilizar dados de fácil obtenção e que permitissem sua utilização em diversas localidades. O modelo foi avaliado para as condições das regiões Sul e Centro-Oeste entre as safras entre 2002 a 2006. Comparou-se as estimativas com os dados experimentais, verificando-se o bom desempenho do método para as regiões estudadas, com R²=0,54 numa análise global, mas com R²=0,97 para Dourados (MS) e R²=0,70 para Londrina (PR).CBA 2009

The Galactic centre mini-spiral in the mm-regime

The mini-spiral is a feature of the interstellar medium in the central ~2 pc of the Galactic center. It is composed of several streamers of dust and ionised and atomic gas with temperatures between a few 100 K to 10^4 K. There is evidence that these streamers are related to the so-called circumnuclear disk of molecular gas and are ionized by photons from massive, hot stars in the central parsec. We attempt to constrain the emission mechanisms and physical properties of the ionized gas and dust of the mini-spiral region with the help of our multiwavelength data sets. Our observations were carried out at 1.3 mm and 3 mm with the mm interferometric array CARMA in California in March and April 2009, with the MIR instrument VISIR at ESO's VLT in June 2006, and the NIR Br-gamma with VLT NACO in August 2009. We present high resolution maps of the mini-spiral, and obtain a spectral index of 0.5 for Sgr A*, indicating an inverted synchrotron spectrum. We find electron densities within the range 0.8-1.5x10^4 cm-3 for the mini-spiral from the radio continuum maps, along with a dust mass contribution of ~0.25 solar masses from the MIR dust continuum, and extinctions ranging from 1.8-3 at 2.16 micron in the Br-gamma line. We observe a mixture of negative and positive spectral indices in our 1.3 mm and 3 mm observations of the extended emission of the mini-spiral, which we interpret as evidence that there are a range of contributions to the thermal free-free emission by the ionized gas emission and by dust at 1.3 mm.Comment: 9 pages, 11 figures, accepted to A&

Hydrogen atom in a spherical well: linear approximation

We discuss the boundary effects on a quantum system by examining the problem of a hydrogen atom in a spherical well. By using an approximation method which is linear in energy we calculate the boundary corrections to the ground-state energy and wave function. We obtain the asymptotic dependence of the ground-state energy on the radius of the well.Comment: Revised version to appear in European Journal of Physic

Fixação biológica de nitrogênio: Bactérias fixadoras de nitrogênio de importância para a agricultura tropical.

Diazotrofos de vida livre. Diazotrofos associativos. Endófiticos facultativos. Endofíticos obrigatórios. Diazotrofos simbióticos.bitstream/CNPAB-2010/27316/1/doc091.pd

Local-field correction to one- and two-atom van der Waals interactions

Based on macroscopic quantum electrodynamics in linearly and causally responding media, we study the local-field corrected van der Waals potentials and forces for unpolarized ground-state atoms placed within a magnetoelectric medium of arbitrary size and shape. We start from general expressions for the van der Waals potentials in terms of the (classical) Green tensor of the electromagnetic field and the atomic polarizability and incorporate the local-field correction by means of the real-cavity model. In this context, special emphasis is given to the decomposition of the Green tensor into a medium part multiplied by a global local-field correction factor and, in the single-atom case, a part that only depends on the cavity characteristics. The result is used to derive general formulas for the local-field corrected van der Waals potentials and forces. As an application, we calculate the van der Waals potential between two ground-state atoms placed within magnetoelectric bulk material.Comment: 9 pages, 2 figures, corrections according to erratu