Analysis of azimuthal variation of rain attenuation

The attenuation due to rain is the main source of impairments in satellite links operating above 10 GHz. In the design of systems based on Low Earth Orbit (LEO) satellites, the analysis of the rain attenuation must take into account both azimuth and elevation variations. It requires a deep knowledge on the nature of this dependence. As measurements at several elevation and azimuth angles are not available, it is necessary to use prediction models that aim at reproducing the rain profiles of each link. This paper presents an analysis of the azimuth dependence of rain attenuation according to the size of the azimuthal window where this attenuation occurs. It is shown that the azimuthal rain attenuation windows smaller than 180° are few at higher elevation but their probability increases exponentially with the decreasing of the elevation

Many-body symbolic dynamics of a classical oscillator chain

We study a certain type of the celebrated Fermi-Pasta-Ulam particle chain, namely the inverted FPU model, where the inter-particle potential has a form of a quartic double well. Numerical evidence is given in support of a simple symbolic description of dynamics (in the regime of sufficiently high potential barrier between the wells) in terms of an (approximate) Markov process. The corresponding transition matrix is formally identical to a ferromagnetic Heisenberg quantum spin-1/2 chain with long range coupling, whose diagonalization yields accurate estimates for a class of time correlation functions of the model.Comment: 22 pages in LaTeX with 14 figures; submitted to Nonlinearity ; corrected page offset proble

Influence of Different Yeast Strains on Metabolism of Tryptophan and Indole-3-Acetic Acid During Fermentation

The effect of supplementation of Riesling (Vitis vinifera L.) must with ammonium sulphate (AS) ontryptophan (Trp) and indole-3-acetic acid (IAA) metabolism during alcoholic fermentation with fourcommercial yeast strains (Uvaferm CEG, Lalvin Cross Evolution, Anchor VIN 13 and Anchor exoticSPH) were examined. AS addition reduced Trp uptake by yeasts from 1% to 15%. Wines produced byAnchor VIN 13 and Uvaferm CEG yeasts with AS addition had the highest concentrations of Trp (0.60and 0.59 mg/L respectively). Concentrations of total and bound IAA decreased during all treatments. Atthe end of fermentation the highest concentration of free IAA was measured in the control must inoculatedwith Anchor VIN 13 yeast (35.83 μg/L) and the lowest in the sample inoculated with Uvaferm CEG yeast(13.08 μg/L). Anchor VIN 13 yeast showed the strongest change in metabolism due to AS addition duringfermentation. 2-Aminoacetophenone (2-AAP) formation was not observed in all the studied wines

Crescimento vegetativo, floração e frutificação efetiva do pessegueiro 'Jubileu' submetido a diferentes comprimentos de interenxertos.

O objetivo deste trabalho foi avaliar os efeitos do uso de interenxertos, com diferentes comprimentos, sobre o vigor de plantas de pessegueiro da cultivar Jubileu. Foram utilizados interenxertos da cultivar de baixo vigor, Granada, com 5, 10, 15 e 20 cm de comprimento. Avaliaram-se o crescimento vegetativo, a floração e a frutificação efetiva das plantas. O experimento foi conduzido em Pelotas, RS, de março de 2007 a dezembro de 2008. O crescimento vegetativo do pessegueiro 'Jubileu' está diretamente relacionado ao comprimento do interenxerto. O aumento do comprimento do interenxerto antecipa o início da floração e da plena floração. A redução do vigor, induzida por interenxertos de maior comprimento, promove aumento na diferenciação floral. O interenxerto com 20 cm intensifica a redução do vigor, mas aumenta a mortalidade das plantas. Portanto, os interenxertos com 10 e 15 cm de comprimento são os mais adequados para o adensamento de pomares