Polimorfismo de (GA)n intra e inter SSR em germoplasma mandioca.

O objetivo do trabalho foi comparar o polimorfismo de (GA)n Inter e Intra SSR na análise preliminar de acessos de germoplasma mantidos no Campo Experimental do Caldeirão, município de Iranduba

Desenho preliminar de uma coleção nuclear de mandioca dentro do banco ativo de germoplasma da Embrapa Amazônia Ocidental.

A mandioca (Manihot esculenta Crantz) destaca-se como um dos cultivos mais importantes na Amazônia, tanto para a segurança alimentar regional como no comércio. A Embrapa Amazônia Ocidental organizou um Banco Ativo de Germoplasma (BAG) para fins de melhoramento e conservação in vivo da variabilidade genética da mandioca, por meio da coleta de germoplasma em diferentes localidades no Estado do Amazonas, visando reunir a diversidade encontrada na região amazônica. O objetivo deste trabalho foi desenhar uma coleção nuclear de mandioca com base em dados geográficos, morfo-agronômicos e genético-moleculares. Decidiu-se que a Coleção Nuclear deveria conter 50 amostras, representando 15% do BAG e serão representadas por acessos coletados nas calhas dos principais rios Negro, Solimões, Purus, Amazonas e Madeira. As localidades super-representadas no BAG serão alocadas à CN logaritmicamente, enquanto que as localidades sub-representadas serão alocadas proporcionalmente. As amostras selecionadas para a Coleção devem possuir boa produtividade (>13,3 t/há), raízes com polpa de coloração amarelada, teores de HCN acima de 100 mg/kg e divergência genético-moleculares satisfatórias

Da inspeção à avaliação de segurança na reabilitação de estruturas de madeira

A avaliação de estruturas existentes em madeira e consequente planeamento de intervenções requer conhecimentos específicos provindos de diferentes fontes e áreas técnicas, devendo estas serem complementares e aferidas por meio do uso de uma metodologia de inspeção e diagnóstico sistemática e rigorosa. Este trabalho apresenta, de forma resumida, as diferentes fases consideradas na avaliação estrutural de uma construção existente em madeira desde a fase inicial de diagnóstico e inspeção até à escolha de possíveis métodos para a avaliação de segurança, sendo estas fases fundamentais para a definição adequada do plano de intervenções a tomar posteriormente

Genetic diversity among homonymy accessions maintained in the cassava regional Brazilian genebank.

In the Amazon region, the cassava cultivation has great social and economic importance because its production is source of food for traditional population and income for small farmers. The cassava farmer fields are results of the tradition and the preference of consumption and represent the genetic variability of many characters related to the mode of use and the quality of cassava root. The identification of genotypes to generate improved clones has been supported by germplasm conservation, evaluation and molecular characterization

Characterization of cross sections from old chestnut beams weakened by decay

This work aims to experimentally assess the material properties of old chestnut (Castanea sativa Mill.) cross sections weakened by decay. Specimens were taken from critical zones of twenty floor beams, mostly corresponding to their ending parts, in contact with granite masonry walls. These specimens were compared with clear wood specimens taken from non-decayed parts . The experimental campaign comprised of visual inspection, non-destructive testing (ultra-sound, impact penetration and drilling resistance tests) and uniaxial compression tests, parallel to the grain. Pin penetration test evidenced a depth of penetration 36% higher for decayed specimens compared to non-decayed specimens, proving the loss of capacity in the superficial decayed layer. The results of decayed specimens exhibited a decrease of approximately 30% in the compressive strength parallel to the grain. A reduction of approximately 5% was found for the dynamic and elastic moduli. The coefficients of variation for decayed specimens are significantly higher than for sound specimens. Different decay models are considered and compared aiming at analyzing decay evolution along time and determining the decrease of load bearing cross section. Finally, the results were used to calibrate a bi-parametrical decay model for above ground timber structures, considering a linear relation between time and decay depth.Fundação para a Ciência e a Tecnologia (FCT

Use of random sampling and Bayesian methods in the prediction of chestnut timber beams bending stiffness

The assessment of global bending stiffness of three old timber beams is predicted by use of random sampling and Bayesian Network approaches. The information for the prediction models derive from the visual grading and localized mechanical testing of 20 beams retrieved from the same building, which have been scope of analysis in previous studies. Although the results indicate moderate correlations between predicted and experimental results, significant percentage errors are also found. To minimize the percentage error between experimental and predicted values, coefficients corresponding to the scale effect relation between existing chestnut timber elements with round cross section and sawn beams of smaller dimensions with rectangular cross section were proposed.Fundação para a Ciência e a Tecnologia (FCT)Agência de Inovação (ADI

Prediction of global bending stiffness of timber beams by local sampling data and visual inspection

The results of visual inspection according to UNI 11119:2004 and bending tests made on 20 old chestnut (Castanea sativa Mill.) beams according to EN 408:2010 were statistically analyzed in order to provide a consistent and feasible procedure to predict their modulus of elasticity (MOE) in bending. Local data obtained from smaller size specimens was used for the prediction of the global mechanical properties of full structural size members and compared with the results of mechanical tests. The prediction models took into account the visual strength classes and the influence of defects on the determination of the MOE. Moreover, random sampling was considered in order to demonstrate the possibility of using smaller representative samples, thus avoiding excessive need of removal of on-site samples and allowing for a smaller number of mechanical tests. The models using random sampling predicted the behavior of full size scale elements accurately, with strong correlations to the experimental results (coefficient of determination r2 ranging from 0.70 to 0.79) and a percentage error lower than 20 %, thus allowing a reliable estimation of mechanical characteristics of existing timber members with a combination of visual inspection and local sampling.Fundação para a Ciência e a Tecnologia (FCT