A viabilidade da pequena propriedade, a viabilidade do pequeno produtor.

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Boas práticas de manipulação na colheita de mel.

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Vacuum fluctuations of a scalar field near a reflecting boundary and their effects on the motion of a test particle

The contribution from quantum vacuum fluctuations of a real massless scalar field to the motion of a test particle that interacts with the field in the presence of a perfectly reflecting flat boundary is here investigated. There is no quantum induced dispersions on the motion of the particle when it is alone in the empty space. However, when a reflecting wall is introduced, dispersions occur with magnitude dependent on how fast the system evolves between the two scenarios. A possible way of implementing this process would be by means of an idealized sudden switching, for which the transition occurs instantaneously. Although the sudden process is a simple and mathematically convenient idealization it brings some divergences to the results, particularly at a time corresponding to a round trip of a light signal between the particle and the wall. It is shown that the use of smooth switching functions, besides regularizing such divergences, enables us to better understand the behavior of the quantum dispersions induced on the motion of the particle. Furthermore, the action of modifying the vacuum state of the system leads to a change in the particle energy that depends on how fast the transition between these states is implemented. Possible implications of these results to the similar case of an electric charge near a perfectly conducting wall are discussed.Comment: 17 pages, 8 figure

Redox signaling, Nox5 and vascular remodeling in hypertension

Purpose of review: Extensive data indicate a role for reactive oxygen species (ROS) and redox signaling in vascular damage in hypertension. However, molecular mechanisms underlying these processes remain unclear, but oxidative post-translational modification of vascular proteins is critical. This review discusses how proteins are oxidatively modified and how redox signaling influences vascular smooth muscle cell growth and vascular remodeling in hypertension. We also highlight Nox5 as a novel vascular ROS-generating oxidase. Recent findings: Oxidative stress in hypertension leads to oxidative imbalance that affects vascular cell function through redox signaling. Many Nox isoforms produce ROS in the vascular wall, and recent findings show that Nox5 may be important in humans. ROS regulate signaling by numerous processes including cysteine oxidative post-translational modification such as S-nitrosylation, S-glutathionylation and sulfydration. In vascular smooth muscle cells, this influences cellular responses to oxidative stimuli promoting changes from a contractile to a proliferative phenotype. Summary: In hypertension, Nox-induced ROS production is increased, leading to perturbed redox signaling through oxidative modifications of vascular proteins. This influences mitogenic signaling and cell cycle regulation, leading to altered cell growth and vascular remodeling in hypertension

Avaliação dos impactos econômicos, sociais e ambientais de tecnologias da Embrapa Pecuária Sudeste. 4. Técnicas de produção intensiva aplicadas a propriedades familiares produtoras de leite.

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Alternativas inovadoras para otimizar a transferência de tecnologia para a agricultura familiar.

Editado por Flávio Augusto Portela Santos, José Carlos de Moura, Vidal Pedroso de Faria

Assentamentos rurais sustentáveis: o processo de construção participativa do conhecimento agroecológico e o monitoramento de unidades de referência no Assentamento Sepé Tiaraju-SP.

Relato das experiências de instalação e monitoramento do assentamento Sepé Tiaraju, primeira iniciativa no estado de São Paulo na modalidade projeto de desenvolvimento sustentável preconizada pela portaria nº 477/99 do INCRA. Trata-se de uma experiência inovadora na construção de um modelo alternativo de assentamento, tendo a Agroecologia como centro da matriz tecnológica e a cooperação como eixo da organização produtiva. Nesse sentido, um grupo de famílias assentadas, em conjunto com uma equipe da Embrapa Meio Ambiente e outras instituições parceiras, deu início em 2005, ao processo de construção coletiva do conhecimento agroecológico no assentamento. O eixo condutor dos trabalhos no Assentamento Sepé Tiaraju foi pautado a partir dos sistemas agroecológicos, com ênfase nos sistemas agroflorestais (SAFs).bitstream/item/85831/1/Doc-93.pd