NUMERICAL MODELING OF THE PLANETARY BOUNDARY LAYER

This work describes the major available techniques to simulate the time and space evolution of the planetary boundary layer. For homogeneous and equilibrium conditions the structure of the planetary boundary layer can be diagnosed from the Monin-Obukhov, Free Convection, Local and Mixed Layer Similarity theories. For the other atmospheric conditions the planetary boundary layer can be numerically simulated using first and second order closure models and large eddy models. The closure models take into consideration the traditional statistical approach. Large eddy simulation models are based on the filtered equations of motion and require the statistical approach to estimate subgrid turbulence

Avaliação de pastagens nativas de terra firme do Médio Amazonas.

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Sistema de produção de leite em Terra Alta, Pará.

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Les Modeling of a Diurnal Cycle

LES modeling of a diurnal cycl

Enhanced resistance to citrus canker in transgenic sweet orange expressing the sarcotoxin IA gene.

Citrus canker, caused by the bacterial pathogen Xanthomonas citri subp. Citri (Xcc), is a serious disease reported in most citrus-producing areas around the world. Although different levels of field resistance to citrus canker have been reported in sweet oranges, they are usually not sufficient to provide adequate control of the disease. Ectopic over-expression of antibacterial genes is one of the potential strategies to increase plant resistance to bacterial diseases. Previous in vitro results showed that sarcotoxin IA, an antimicrobial peptide isolated from the flesh fly (Sarcophaga peregrina), can be efficient to control different plant pathogenic bacteria, including Xcc. Transgenic BPera^ sweet orange (Citrus sinensis [L.] Osbeck) plants constitutively expressing the sarcotoxin IA peptide fused to the PR1a signal peptide from Nicotiana tabacum for secretion in the intercellular space were obtained by Agrobacteriummediated transformation using thin sections of mature explants. Citrus canker resistance evaluation in leaves of transgenic and non-transgenic plants was performed through inoculations with Xcc by infiltration and spraying. The Xcc population was up to 2 log unit lower in leaves of the transgenic plants compared to those of non-transgenic controls. Incidence of canker lesions was significantly higher in non-transformed controls (>10 lesions/cm2) than in the transgenic plants (<5 lesions/ cm2) after injection infiltration or spraying with Xcc inoculum. Accumulation of sarcotoxin IA peptide in sweet orange tissue did not cause any deleterious effects on the growth and development of the transgenic plants, indicating this approach is suitable to provide resistance to citrus canker

Antioxidant films from mango kernel components.

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The Richardson's Law in Large-Eddy Simulations of Boundary Layer flows

Relative dispersion in a neutrally stratified planetary boundary layer (PBL) is investigated by means of Large-Eddy Simulations (LES). Despite the small extension of the inertial range of scales in the simulated PBL, our Lagrangian statistics turns out to be compatible with the Richardson $t^3$ law for the average of square particle separation. This emerges from the application of nonstandard methods of analysis through which a precise measure of the Richardson constant was also possible. Its values is estimated as $C_2\sim 0.5$ in close agreement with recent experiments and three-dimensional direct numerical simulations.Comment: 15 LaTex pages, 4 PS figure