Diferenciação de cultivares de feijão de origem transgênica e convencional por RMN HR-MAS de 1H e análise quimiométrica.

O objetivo do presente estudo foi avaliar as diferenças na composição química dos grãos dos cultivares Olathe Pinto convencional e o seu geneticamente modificado (Olathe Pinto 5.1) e uma possível transferência gênica aos cultivares Pontal e Perola, utilizando a ressonância magnética nuclear, em análise particular da técnica HR-MAS, e técnicas quimiométricas.Conpeex 2010

Coffee Production: An Analysis of Opportunities for Competitiveness

This study involved rural properties of the Brazilian Cerrado, which are necessarily consistent with the requirements of good agricultural practices for quality, innovation, and technology in the production and management of properties. Based on the knowledge and information as value-added production factors, we sought to highlight the opportunities for improving competitiveness, and thus a review of the literature on competitiveness, knowledge, and information as a differential factor for production with added value, innovation, and territorial technology as well as entrepreneurship. With the data from the field study, the objective was to show how knowledge and information, applied in production and social capital, can leverage competitiveness. The analyzes carried out using AHP indicate that some initiatives already aid in the promotion of innovation and technology applied to production, making it necessary, however, to encourage knowledge and information among producers and other stakeholders collectively, for the best costs and results. They also point to the low concern of producers with training and other productivity improvement techniques, such as selective harvesting. Authenticated that the producers opt for the sale of their production via commodity, aiming to profit quickly. Reasons for this are, in the non-perception of value added (sales in commodity); in the absence of rural structure for the processing and harvesting of the coffee required for special sale; in the precariousness of collective export agents (cooperatives are dependent on traders) and deficiencies in management for positioning in the properties (most work in scale)

Characterization of cover crops by NMR spectroscopy: impacts on soil carbon, nitrogen and phosphorus under tilage regimes.

The objective of this study was to investigate the chemical composition of cover crops by solid-state CPMAS 13C NMR spectroscopy and its effects on carbon, nitrogen and phosphorus in a Typic Acrustox. Cover crops (Crotalaria juncea, Canavalia brasiliensis, Cajanus cajan, Mucuna pruriens and Raphanus sativus) and natural fallow were studied in rotation with maize under conventional and no-tillage regimes. Tissues of Crotalaria juncea, Canavalia brasiliensis, Mucuna pruriens and Raphanus sativus were analyzed using CPMAS 13C NMR spectroscopy. Soil samples were collected at the end of the growing season of the cover crops (September 2002) and during the grain filling period in corn from 0-5 and 5-10 cm layers. Cajanus cajan presented the lowest content of polysaccharides and along with Mucuna pruriens presented the highest percentage of aromatic carbon compounds, reflecting the slow decomposition of highly lignified material. Carbon stocks were higher in the superficial soil layer and under no-tillage due to the accumulation and slower decomposition of plant tissues under these conditions. Increases in the C/N ratio of the soil with Mucuna pruriens and the C/P ratio with Cajanus cajan in the dry season were also related to slower rates of decomposition, caused by the large concentration of aromatic compounds in the tissues of these species. The higher C/P ratios found at 0-5 cm layer are due to higher values of P (Mehlich-1) at 5-10 cm (25 mg kg-1) layer and the higher concentration of carbon in the superficial soil layer as a result of the accumulation of plant residues

Potencial da fixação biológica de nitrogênio em genótipos ancestrais de feijão-caupi.

O conceito de agricultura sustentável é uma resposta relativamente recente à degradação dos recursos naturais ou da base produtiva da agricultura moderna. O uso da fixação biológica de nitrogênio (FBN) como insumo biológico, figura nesse contexto como possibilidade de uma agricultura que seja economicamente viável e ecologicamente correta. O objetivo deste trabalho foi identificar materiais utilizados no melhoramento genético da cultura do feijão-caupi com potencial para a FBN

Percolation Threshold, Fisher Exponent, and Shortest Path Exponent for 4 and 5 Dimensions

We develop a method of constructing percolation clusters that allows us to build very large clusters using very little computer memory by limiting the maximum number of sites for which we maintain state information to a number of the order of the number of sites in the largest chemical shell of the cluster being created. The memory required to grow a cluster of mass s is of the order of $s^\theta$ bytes where $\theta$ ranges from 0.4 for 2-dimensional lattices to 0.5 for 6- (or higher)-dimensional lattices. We use this method to estimate $d_{\scriptsize min}$, the exponent relating the minimum path $\ell$ to the Euclidean distance r, for 4D and 5D hypercubic lattices. Analyzing both site and bond percolation, we find $d_{\scriptsize min}=1.607\pm 0.005$ (4D) and $d_{\scriptsize min}=1.812\pm 0.006$ (5D). In order to determine $d_{\scriptsize min}$ to high precision, and without bias, it was necessary to first find precise values for the percolation threshold, $p_c$: $p_c=0.196889\pm 0.000003$ (4D) and $p_c=0.14081\pm 0.00001$ (5D) for site and $p_c=0.160130\pm 0.000003$ (4D) and $p_c=0.118174\pm 0.000004$ (5D) for bond percolation. We also calculate the Fisher exponent, $\tau$, determined in the course of calculating the values of $p_c$: $\tau=2.313\pm 0.003$ (4D) and $\tau=2.412\pm 0.004$ (5D)

Relative water content in two grass cultivars in crop-livestock system in the State of Tocantins, Brazil.

In this presentation, we report the results of two grasses on Integrated Crop-Livestock System in the Tocantins Cerrado

Avaliação do desempenho de estirpes de rizóbio em feijão-caupi: dados de rede referente ao 1º ano de experimentação.

Este trabalho teve como objetivo apresentar os resultados de avaliação da inoculação de estirpes de rizóbio em feijão-caupi, como critério para a recomendação de estirpes