Wind reversals in turbulent Rayleigh-Benard convection

The phenomenon of irregular cessation and subsequent reversal of the large-scale circulation in turbulent Rayleigh-B\'enard convection is theoretically analysed. The force and thermal balance on a single plume detached from the thermal boundary layer yields a set of coupled nonlinear equations, whose dynamics is related to the Lorenz equations. For Prandtl and Rayleigh numbers in the range $10^{-2} \leq \Pr \leq 10^{3}$ and 10^{7} \leq \Ra \leq 10^{12}, the model has the following features: (i) chaotic reversals may be exhibited at Ra $\geq 10^{7}$; (ii) the Reynolds number based on the root mean square velocity scales as \Re_{rms} \sim \Ra^{[0.41 ... 0.47]} (depending on Pr), and as $\Re_{rms} \sim \Pr^{-[0.66 ... 0.76]}$ (depending on Ra); and (iii) the mean reversal frequency follows an effective scaling law \omega / (\nu L^{-2}) \sim \Pr^{-(0.64 \pm 0.01)} \Ra^{0.44 \pm 0.01}. The phase diagram of the model is sketched, and the observed transitions are discussed.Comment: 4 pages, 5 figure

The perspective for the use of genetically modified common beans in Brazil based on genetic diversity of Bean golden mosaic virus.

Bean golden mosaic is the most important viral disease affecting common beans (Phaseolus vulgaris) in Brazil. It is caused by Bean golden mosaic virus (BGMV) and is prevalent in all bean producing areas. Aiming to control the disease, a transgenic bean elite line was developed with an intron-hairpin construction to silence the AC1 viral gene. This line shows high resistance to BGMV with the capacity to contain the replication of the virus both in the greenhouse and in the field

Distribuição das atividades de consumo e ruminação ao longo do dia de ovinos sem padrão racial definido alimentados com farelo de castanha de caju.

Resumo: Avaliou-se as distribuições das atividades de consumo e ruminação ao longo do dia de ovinos machos, não-castrados e sem padrão racial definido, com aproximadamente quatro meses de idade e peso corporal médio de 16,2 ± 3,1 kg, recebendo feno de capim-tifton 85 como volumoso exclusivo e suplementados com farelo de castanha de caju. O delineamento experimental foi o inteiramente casualizado, com quatro tratamentos experimentais, com seis repetições por tratamento. O comportamento ingestivo dos animais foi determinado em intervalos de cinco minutos durante 24 horas.A soma dos períodos 1 e 2, referentes ao período de 6 as 12 h e de 12 as 18 h, correspondeu ao maior tempo despendido com consumo (83,3% do consumo total), concentrando-se durante o dia. Já a ruminação dos animais ocorreu principalmente no período noturno (24 as 6 h), horário em que comumente a temperatura do ar é mais amena. O consumo de alimento concentra-se durante o dia, enquanto que, a ruminação concentra-se durante a noite. Distribution of consumption and ruminating activities over the day without defined breed sheep fed bran cashews. Abstract: Evaluated the distributions of consumption and ruminating activities over the day of male sheep, non castrated and no defined breed, approximately four months of age and average body weight of 16.2 ± 3.1 kg, receiving hay tifton 85 as sole forage supplemented with bran and cashews. The experimental design was completely randomized, with four experimental treatments with six replicates per treatment. The eating behavior of animals was tested every five minutes for 24 hours. The sum of periods 1 and 2, for the period of 6 to 12 h and from 12 to 18 h, corresponding to the longer time spent on consumption (83.3% of total consumption), concentrating during the day. Already ruminating animals occurred primarily at night (24 to 6 h), a time that usually air temperature and milder. The food consumption is concentrated during the day, whereas rumination concentrates overnight

Sequência completa do DNA-A de uma nova espécie de Begomovirus infectando tomateiro no Estado de Tocantins, Brasil.

O presente trabalho visou caracterizar uma nova espécie de Begomovirus detectada infectando tomateiro (Solanum lycopersicum L.) no Estado de Tocantins.Resumo 1381. Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves

Registro no Estado do Amazonas de um novo begomovírus do tomateiro relacionado com espécies virais da América Central e Caribe.

Esse trabalho visou caracterizar um isolado de Begomovirus encontrado infectando tomateiro no Estado do Amazonas. Plantas com sintomas de clorose interneral e amarelecimento apical foram coletadas na região produtora de tomate para consumo in natura em Silves-AM.Resumo 1382. Suplemento. Edição dos resumos do 44º Congresso Brasileiro de Fitopatologia, 2011, Bento Gonçalves