Expression of antioxidant genes and photosynthetic apparatus in the soybean crop in competition with Italian ryegrass biotypes.

Crop-weed competition induces stress in plants causing physiological changes which can be evaluated using the RT-qPCR technique. The aim of this study was to evaluate the stability of candidate reference genes and measure the relative gene expression of antioxidant enzymes and components of the photosynthetic apparatus in soybean in competition with glyphosate-susceptible and resistant Italian ryegrass (Lolium multiflorum Lam.). The experiment was carried out in a greenhouse using replacement series between soybean and Italian ryegrass biotypes. In this study, candidate reference genes were evaluated for use as controls in RT-qPCR to quantify gene expression. An evaluation was made of genes that encode catalase, ascorbate peroxidase, superoxide dismutase, chlorophyll a/b, phytochrome A and cytochrome P450 at 50 days after emergence of the soybean. The SKIP and GAPDH genes were the most stable for soybean and Italian ryegrass, respectively. The soybean subjected to the interspecific competition with the glyphosate-resistant Italian ryegrass biotype showed an increase in superoxide dismutase gene expression. The catalase and cytochrome P450 genes were up-regulated in the susceptible biotype while the other genes were down-regulated. However, the soybean crop under interspecific competition with glyphosate-resistant biotye showed as up-regulated for all the genes evaluated. For the photosynthetic apparatus, cytochrome P450 gene was up-regulated under intraspecific competition on both Italian ryegrass biotypes, while the phytochrome A was up-regulated only in the resistant biotype. Thus, the increase in genes investigated represents a potential tool for the genetic improvement of plants to enhance their competitive capacity

Ativação alcalina de cinzas volantes utilizando solução combinada de NaOH e Ca(OH)2

Este trabalho teve como objetivo avaliar o comportamento da resistência à compressão, ao longo do tempo, em amostras de argamassas à base de cinzas volantes álcali-ativadas. Como ativador alcalino foi utilizada uma solução combinada de NaOH e Ca(OH)2. A cura das amostras foi realizada de duas formas distintas. Na primeira, as amostras foram mantidas em estufa à 70°C/12 hs e à temperatura constante de 22°C em sala climatizada até a idade de ensaio. Apesar de serem obtidas resistências da ordem de 20 MPa nas primeiras 24 hs, houve decréscimo da resistência a partir da idade de 7 dias. Verificado esse comportamento, um segundo método de cura foi adotado. Para isso, o traço utilizado para o preparo de novas argamassas foi o mesmo adotado no método anterior. Porém, foram submetidas à temperatura constante de 70°C até a idade de ensaio. Nesse caso, as amostras apresentaram decréscimo mais acentuado da resistência em menor espaço de tempo, quando comparado às amostras curadas no primeiro método. Como estudos complementares foram realizadas análises microestruturais da CV antes e depois da ativação, utilizando o MEV/EDS.The main objective of this work was to evaluate the development of the compressive strength, along time, in alkali-activated fly ash mortars. As alkaline activator a combined solution of NaOH and Ca(OH)2 was used. The cure of the samples was carried through two distinct forms. In the first one, samples were kept in oven at 70°C during the first 12 hours and at constant room temperature of 22°C afterwards, until the age of testing. Compressive strength of 20 MPa magnitude were achieved during the first 24 hours, however it started to decrease after the age of 7 days. Considering this behaviour, second method of curing was adopted for the same mixing proportions. However, mortar samples were kept in oven at 70°C until the age of testing. In this case, compressive strength results decreased more significantly and at earlier ages, when compared with the results of samples cured using the first method. As complementary to understand the decreasing in compressive strength, microstructural analyses of the fly ash, before and after the activation, have been carried out, using the SEM/EDS

Cinzas volantes álcali-ativadas com solução combinada de NaOH e Ca(OH)2

Este trabalho teve como objetivo avaliar o comportamento da resistência à compressão, ao longo do tempo, em amostras de argamassas à base de cinzas volantes álcali-ativadas. Como ativador alcalino foi utilizada uma solução combinada de NaOH e Ca(OH)2. A cura das amostras foi realizada de duas formas distintas. Na primeira, as amostras foram mantidas em estufa à 70°C/12 h e à temperatura constante de 22°C em sala climatizada até a idade de ensaio. Apesar de serem obtidas resistências da ordem de 20 MPa nas primeiras 24 h, houve decréscimo da resistência a partir da idade de 7 dias. Verificado esse comportamento, um segundo método de cura foi adotado. Para isso, o traço utilizado para o preparo de novas argamassas foi o mesmo adotado no método anterior. Porém, foram submetidas à temperatura constante de 70°C até a idade de ensaio. Nesse caso, as amostras apresentaram decréscimo mais acentuado da resistência em menor espaço de tempo, quando comparado às amostras curadas no primeiro método. Como estudos complementares foram realizadas análises microestruturais da CV antes e depois da álcali-ativação, utilizando o MEV/EDS. Nas imagens microestruturais foi possível identificar três morfologias distintas nas pastas álcali-ativadas: uma composta de regiões com aspecto denso; outra apresentando partículas de cinzas volantes parcialmente solubilizadas; e outra mostrando a formação de produtos em forma de cristais aciculares. Porém, apenas o uso do MEV/EDS não foi suficiente para que se pudesse entender o mecanismo de reação deletéria provocada entre os ativadores alcalinos e a cinza volante. Portanto, trabalhos futuros deverão contemplar o uso de ferramentas auxiliares às adotadas nesse trabalho com o objetivo de esclarecer tal mecanismo deletério.The main objective of this work was to evaluate over time the development of the compressive strength of alkali-activated fly ash mortars. A combined solution of NaOH and Ca(OH)2 was used as alkaline activator. The curing of the samples was carried out in two distinct ways. In the first one, samples were kept at 70°C during the first 12 hours after mixing and at 22°C afterwards, until the age of testing. Although compressive strengths of about 20 MPa were achieved during the first 24 hours, the strength started to decrease after 7 days. Considering this behaviour, a second method of curing was adopted. The mix proportions were the same as before, however the mortar samples were kept in an oven at 70°C until the age of testing. In this case, the compressive strength values decreased more significantly and in a shorter period of time, as compared to the results obtained for samples cured using the first method. Complementary studies were performed in order to better understand the observed reduction in compressive strength. Microstructural analyses of the fly ash, before and after the alkali-activation, have been carried out using Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS). It was possible to identify three different morphologies in the alkali-activated pastes: one composed by regions with dense aspect; other showing partially solubilised particles of fly ash; and a third showing the formation of products with a needle-like shape. The information provided by the SEM/EDS experiments was not enough to enable the complete understanding of the mechanism of the deleterious reaction that took place among the alkaline activators and the fly ash. Therefore, future studies should address this question by using additional analysis tools in order to clarify this deleterious mechanism

Constraint of the magnetic moment of the top quark

We derive a bound on the magnetic dipole moment of the top quark in the context of the effective Lagrangian approach by using the values of the ratio $R_b = \Gamma_b/\Gamma_h$, $R_l = \Gamma_h/\Gamma_l$ and $\Gamma_Z$. We found that the oblique corrections are more sensible than the vertex ones for this moment.Comment: 6 pages, 3 figures, RevTe

Avaliação dos efeitos da fertirrigação e irrigação na solução do solo em pomar de macieira na região dos Campos de Cima da Serra.

A disponibilidade de nutrientes na solução do solo representa um fator importante no manejo da fertilidade do solo em pomares de macieira, visando à obtenção de elevadas produtividades e qualidade de frutos ideal