Interação entre microrganismos do solo, feijoeiro e milho em monocultura ou consórcio

Differences in crop systems reflect in soil microorganisms and in this work some interactions among agronomically important microorganisms and common bean (Phaseolus vulgaris) and maize (Zea mays) grown in monoculture or intercropped were studied. Under controlled conditions, both bean and maize exudates stimulated rhizobial survival, growth, and nod gene inducing activity, bean nodulation and N accumulation in tissues, and Azospirillum lipoferum survival. After two years with bean and maize in monoculture or intercropped, Azospirillum spp. population was high and did not differ between treatments, while Rhizobium tropici, nitrite oxidizers and soil biomass were favored by bean plants. Rhizobium etli represented, on average, 15% of rhizobial population, except for soils with maize grown alone, where this species was absent, predominating Rhizobium spp., which nodulate exclusively leucaena (Leucaena leucocephala). Soil extracts from the intercropped system showed higher content of nod gene inducing phenolic compounds. Mycorrhizal spore number was not affected by the treatments, although bean in monoculture favored species diversity.Os sistemas de cultivo afetam a microbiota do solo e, neste estudo, procurou-se investigar algumas interações entre microrganismos de importância agrícola e o feijoeiro (Phaseolus vulgaris) e milho (Zea mays) em monocultura ou consórcio. Em condições controladas, tanto os exsudatos de feijão como os de milho estimularam a sobrevivência, o crescimento e a indução do genes nod de Rhizobium, a nodulação e o acúmulo de N no feijoeiro e a sobrevivência de Azospirillum lipoferum. Em um solo cultivado por dois anos com feijoeiro e milho em monocultura e consórcio, a população de Azospirillum spp. foi elevada e não diferiu entre os tratamentos, enquanto a população de Rhizobium tropici, os oxidantes do nitrito e a biomassa microbiana foram favorecidas pela presença do feijoeiro em consórcio ou monocultura. A espécie Rhizobium etli representou cerca de 15% da população rizobiana, exceto na monocultura de milho, em que esteve ausente e na qual predominou Rhizobium spp., capaz de nodular somente leucena (Leucaena leucocephala). Extratos de solo sob consórcio apresentaram teores mais elevados de compostos fenólicos indutores dos genes nod de Rhizobium. Os tratamentos não afetaram o número de esporos de fungos micorrízico-arbusculares, embora o feijoeiro em monocultura tenha proporcionado maior diversidade de espécies fúngicas

Safety and Quality in the Agricultural Product Chain in Brazil

An agriculture-intensive country should be aware of natural toxins, including both mycotoxins and cyanotoxins, which are closely associated with the quality of raw materials, for food safety and industry. The major production chains – corn, wheat, beef, and broiler chicken – are the top components of agribusiness, and they should be tracked by reliable and practical tools. The corn chain is of particular concern in food production; intensive controls, multi-year mycotoxin monitoring, and improved harmless/sustainable management methods for uninterrupted farming in the tropic-subtropics are needed to achieve a long-lasting trend. The rapid control of natural toxins (mycotoxin and cyanotoxin) has focused on immunochemical methods developed with highly specific monoclonal antibodies (mAb) matched with chromatographic methods. In parallel, the promising widespread application of non-destructive analytical methods based on NIR (Near Infrared Reflectance) spectroscopy, computer vision and hyperspectral imaging coupled with multivariate analyses have been introduced as an alternative for the prediction of quality and compositional parameters. Rapid quality control and product traceability are discussed, as well as accurate monitoring, which is essential for potentially launching an innovative system for food production in Brazil

Analisando as pesquisas em educação especial no Brasil Analysing research in special education in Brazil

Nosso objetivo foi examinar a articulação lógica entre o problema e a proposição teórico-metodológica das produções na área da Educação Especial, focando os seus pressupostos epistemológicos. Nos fundamentamos nos pressupostos das tendências empírico-analítica, fenomenológica-hermenêutica, crítico-dialética e do paradigma da complexidade. O procedimento adotado foi interpretar todas as dissertações/teses produzidas nos Programas de Pós-Graduação em Educação e Educação Especial do Brasil, que versam sobre Educação Especial, produzidas nos anos de 2001, 2002 e 2003, disponíveis no banco de teses da CAPES. Encontramos as tendências empírica, fenomenológica e dialética. Os equívocos encontrados foram a não inserção da pesquisa entre as produções na área; ausência de criticidade; não posicionamento numa determinada concepção de educação; construção teórica fundamentada em concepções diferentes; falta de coerência nos pressupostos teórico-metodológicos; não explicitação metodológica; não descrição dos procedimentos éticos; e má elaboração dos resumos. Concluímos pela necessidade da melhoria das dissertações/teses para que possamos avançar na produção de conhecimento na área da Educação Especial.<br>Our objective was to analyze the logical articulation between the problem and the theoretical-methodological proposal of studies in the field of Special Education, focusing on the epistemological issues. We based our study on the empiric-analytical tendencies, phenomenology-hermeneutic, critical-dialectical and the complexity paradigm. The procedure that was adopted was interpreting all dissertations/thesis produced in Post-Graduate programs in Education and Special Education in Brazil, which focus on Special Education, produced in 2001, 2002 and 2003, available online at CAPES' thesis database. We found empirical, phenomenological and dialectic tendencies. The errors encountered included the failure to include the research among the productions in the field; lack of critical approach; lack of making explicit what educational conception the study was based on; theoretical construction based on different conceptions; lack of coherence in the theoretical-methodological proposals; lack of methodological specification; absence of ethical procedural descriptions; and poorly written abstracts. We came to the conclusion that improvements in theses /dissertations are necessary so as to continually move forward in the production of knowledge in the field of Special Education