Agricultura e produção de água: o enfoque hidro-agrícola.

É crescente a demanda por água e a visão da agropecuária como produtora de alimentos, fibras e energia, deve ser ampliada para agregar a produção de água. O agricultor .produtor de água" seria aquele que usa tecnologia e conceitos relacionados à agricultura sustentável que aumentam a infiltração de água no solo, enriquecendo o lençol freático. Dentro dessa ótica, o objetivo do trabalho foi demonstrar que práticas adequadas de manejo que possibilitem maior cobertura e estruturação do solo aumentam a infiltração e contribuem para a "produção de água". Foram utilizados dados de cinco anos (1993 a 1997) de um ensaio sobre perdas de solo e água, sob condições de chuva natural, instalado em 1989, na Embrapa Milho e Sorgo, em Sete Lagoas - MG. Os dados mostram que pastagem não degradada e plantio direto são os métodos de manejo de solo e de pasto que maiores garantias oferecem do ponto de vista de conservação de solo e água no sistema, apontando-os como estratégias para aumentar a infiltração de água no solo, garantindo a recarga e o abastecimento d'água à população. Dentro de seu sistema de produção, esse "agricultor produtor de água" deve considerar a água como um de seus insumos e também como um de seus produtos, e seu manejo adequado não pode ser considerado uma etapa independente dentro do processo de produção agrícola, devendo ser analisado dentro do contexto de- um sistema integrado. Essa visão sistêmica da gestão integrada dos recursos hídricos e da produção agrlcola, pode ser chamada de enfoque hidro-agrícola

Confinement in the 3-dimensional Gross-Neveu model

We consider the $N$-components 3-dimensional massive Gross-Neveu model compactified in one spatial direction, the system being constrained to a slab of thickness $L$. We derive a closed formula for the effective renormalized $L$-dependent coupling constant in the large-N limit, using bag-model boundary conditions. For values of the fixed coupling constant in absence of boundaries $\lambda \geq \lambda_c \simeq 19.16$, we obtain ultra-violet asymptotic freedom (for $L \to 0$) and confinement for a length $L^{(c)}$ such that $2.07 m^{-1} < L^{(c)} \lesssim 2.82 m^{-1}$, $m$ being the fermionic mass. Taking for $m$ an average of the masses of the quarks composing the proton, we obtain a confining legth $L^{(c)}_p$ which is comparable with an estimated proton diameter.Comment: Latex, 4 pages, 2 figures (one new), some changes in tex

Soil quality and agricultural sustainability in the Brazilian Cerrado.

The "Cerrado Region" - the acid savannas of Brazil, as many as thirty years ago, were considered as ecosystem unsuitable for agriculture crop production because environmental limitations. However, a burst in agricultural development has taken place in the area during last decades as a result of new technology mainly involving plant breeding and soil management. In spite of the great contribution made by the "Cerrado" region to the Brazilian agricultural production, over the past few years concerns have been raised about the issue of the high costs of this agriculture production and about the issue of soil quality degradation, and how it could affect the sustainability of the agriculture in the "Cerrado" ecosystem. The concept of sustainable agriculture is well recognized research, development, and productive segments of today's agriculture, however, the notion of how to measure and monitor sustainability of farming systems is much les understood. This paper proposes a system of measuring and monitoring the sustainability of farming systems using soil quality indicators in the acid savannas of Brazil. The methodology utilized and agroecological framework to examine the relations among natural resources and agriculture, selectiong one agroecological zone inserted in the cerrado ecosystem. This selected zone was subdivided into regions superimposing Census data, because policy and socioeconomic differences among regions have a considerable influence on land-use systems and options. Target areas were selected and participatory rural appraisal procedure was used to supplement voids in data, identify and characterize predominant farming systems, and to capture farmer knowledge. Using this farmer knowledge, research results already available and local observations, the mainly factors affecting soil quality were identified. Assuming that a management system is sustainable only when soil quality is maintained of improved, physical, chemical and biological properties, processes and characteristics were closen as indicators to make qualitative and quantitative assessment of the changes in soil quality. Based upon these evaluations, a general procedure or framework for sustainability assessment was developed. Using the procedure, it is possible to identify whether current management interventions are contributing towards or away from sustainable farming management, and to develop strategies to improve sustainability of those systems

Efisiensi Beberapa Substrat Dalam Pengujian Viabilitas Benih Berukuran Besar Dan Kecil (Efficiency of Several Substrates for Seed Viability Testing of Large and Small Seeds)

The quality of paper substrate for seed viability testing is determined mainly by the variety and amount of the papers. A study was conducted to find alternative paper and the optimum amount of paper for testing the viability of large and small seed with the rolled paper method. Two experiments were carried out at the Seed Science and Technology Laboratory, Bogor Agricultural University during April-September 2004 and July-December 2007. First experiment: large and small seeds represented by 5 plants (angled loofah, pumpkin, garden pea, bitter gourd, yam bean) and 7 plants (sorghum, cucumber, mungbean, soybean, horenzo, radish and wheat), respectively, were tested on 4 different paper substrates (straw, stencil, CD, and HVS) following the rolled paper method. Second experiment: large seeds of maize and ground nut, and small seeds of rice and mungbean were tested on paper substrates selected from the first experiment, straw, stencil, and CD, with different number of sheet, i.e. 2, 3, 4, and 5 sheets. Each plant seed was considered as an experiment and a randomized block design was applied to all experiments. The result indicated that for the large seeds, stencil and CD papers had equal and high similarity with the reference straw paper substrate, 100% and 80% for germination percentage and dry weight of normal seedlings, respectively. For the small seeds, only stencil paper showed high similarity for germination percentage variable, 86%, with the reference paper, whereas the other paper showed lower similarity, 57% for both CD and HVS papers. The second experiment showed that 2 sheets of straw, stencil or CD papers were enough for testing viability of large and small seeds to obtain germination percentage, but ground nut needs 4 sheets of straw paper. For vigor index variable, efficiency of substrate paper on large and small seeds varied from 2 to 4 sheets

Ceras utilizadas como agentes estructurantes para organogeles de alimentos – Revisión:

Lipids are key ingredients in the human diet. Because of the manipulation and modification of lipids in the food industry, the amount of trans and saturated fat has been substantially increasing in industrialized products. At the same time, the number of studies demonstrating the harmful effects of these foods on human health has increased. Organogels arise as a promising alternative for replacing trans and saturated fat in processed foods. Among the main challenges of preparing an organogel is the difficulty of finding compatible and viable structuring agents in the food industry. Waxes have been studied for this purpose and are one of the most promising organogelators. This article brings a bibliographical review on the recent studies regarding the use of waxes as structuring agents for edible vegetable oils.Los lípidos son ingredientes clave en la dieta humana. Debido a la manipulación y modificación de estos lípidos en la industria alimentaria, la cantidad de grasas trans y las saturadas ha aumentado sustancialmente en los productos industrializados. Al mismo tiempo, ha aumentado la cantidad de estudios que demuestran los efectos nocivos de estos alimentos en la salud humana. Los organogeles surgen como una alternativa prometedora para reemplazar las grasas trans y las saturadas en los alimentos procesados. Entre los principales desafíos de preparar un organogel está la dificultad de encontrar agentes estructurantes compatibles y viables en la industria alimentaria. Las ceras se han estudiado para este propósito y son uno de los organogeladores más prometedores. Este artículo presenta una revisión bibliográfica de los estudios recientes sobre el uso de ceras como agentes estructurantes para aceites vegetales comestibles

Mite (Arthropoda, Acari) associates of palms (Arecaceae) in Brazil: I. Present status and new records.

This paper presents 72 new records and 10 records from literature on the distribuition of nine species of phytophagous mites and nine species of predatory mites from 13 species of palms in 13 Brazilian States