Efeitos da globalização sobre a cultura do milho no Brasil.

A globalizacao, ao permitir um fluxo mais livre de bens e servicos, afeta o mercado onde existem condicoes favoraveis para a movimentacao e modificacao dos bens e servicos. No Brasil, ela afetou a producao de milho ao modificar as condicoes da comercializacao tanto de grao, favorecendo importacoes do Paraguai e da Argentina, como de produtos derivados de sua transformacao (principalmente a exportacao de carne de aves). A alteracao mais dramatica ocorreu no fornecimento dos insumos utilizados na producao. Como resultado das aquisicoes verificadas nos ultimos anos, uma unica empresa multinacional domina 63% do mercado de sementes de milho. Tres outras multinacionais dominam outros 22%. A concorrencia neste mercado ocorre no campo tecnologico, quando reflete o dinamismo dos programas de pesquisa, porem cria condicoes para o direcionamento tecnologico, segundo o interesse de empresas lideres. Outro componente da concorrencia verifica-se no campo financeiro, onde os maiores problemas tem ocorrido para as empresas de capital nacional. Considerando-se o papel estrategico deste segmento da cadeia produtiva do milho, medidas de apoio para pequenas e medias empresas produtivas de sementes e o fortalecimento de atividade de pesquisa publica e privada contribuirao para manter o progresso tecnologico e a competicao no setor

Influência da adubação fosfatada e calagem sobre a absorção do zinco, em dois solos de Minas.

Two experiments were installed in the greenhouse to study the relationships between phosphate fertilization, liming and zinc fertilization. One experiment used a red latosol soil while the other used a dark brown acid soil. Hybrid corn AG 206 was used to plant both experiments. The data collected consisted of dry matter productions level of zinc in the leaves, stems and tootes of the corn as well as the P/Zn and Ca/Zn rations in the leaves. Phosphate fertilization and liming lowed the level of zinc in the corn leaves to a point equal to or lower than 14 ppm. These leves were below 80% of the maximum yields of the experiments. The application of 4,5 ppm of zinc to the soil was adequate to raise the level of zinc in the leaves above the critical level. It also increase the production was limited by a zinc deficiency. The phosphorus and zinc interaction, which ocurred primarily in the roots of the plant, reduced the translocation of zinc to the leaves. The interaction between liming and zinc ocurred prior to the absorption of zinc by the plant. It aprears that there are ratios between phosphorus and zinc between calcium and zinc in the leaves which are critical to good plant growth. The critical P/Zn ratio is betwee 300 and 470 and the critical Ca/Zn ratio between 455-640

Portuguese Adaptation of Students Engagement in Schools International Scale (SESIS)

The importance of student’s engagement has been recently pointed out in research. However, there has been a lack of engagement assessment instrument, pertaining psychometric qualities. Objective: This paper presents the Portuguese adaptation of the “Student’s Engagement in School International Scale” (SESIS), drawn up from a12 countries international study (Lam et al., 2012; Lam et al., in press). Method: Psychometric properties of this scale were examined with data from 685 students from different grades (6th, 7th, 9th and 10th), from both sexes, and different regions of the country. Results: Factorial analysis of the results, with varimax rotation, lead to three different factors which explain 50.88% of the variance. The scale integrates the original 33 items, and cognitive, affective and behavioural dimensions. For the external validity study, the relationship between student’s engagement in school results and other school variables — academic performance, self-concept — was considered, and significant relations were observed, as expected. Conclusion: The data presented highlights the qualities of SESIS, as well as its usefulness for research purposes. Suggestion: It is suggested the investigation of the extension of SESIS’s three-dimensionality, in future studiesKeywords: Innovation, technology, research projects, etc. [Arial 10-point, justified alignment]

Mineralogia da argila de latossolos estimada por alocação a partir do teor total de óxidos do ataque sulfúrico.

E apresentado um metodo de alocacao que estima a composicao mineralogica da argila de latossolos a partir dos teores de oxidos pelos metodos do ataque sulfurico e da difracao de raios X. Esse metodo e adequado para latossolos cuja fracao argila e constituida predominantemente decaulinita, gibbsita, hematita e goethita