Native Cerrado plants are exposed to soils with low pH and high availability of Al. In this study, we measured the Al content in adult plants, and investigated the effects of various Al doses on germination and early development of Eugenia dysenterica plants. For germination tests, the seeds were soaked in Al solution and evaluated for twenty days in growth chambers. In a second experiment, young plants were cultivated in hydroponic systems with various Al concentrations to evaluate the morphological, anatomical and physiological characteristics of E. dysenterica. Anatomical changes and low germinative vigor were observed in seeds germinated in 600 and 800 μmol Al3+ L−1. In the hydroponic system, 200 μmol Al3+ L−1 stimulated root growth in young plants. The activity of antioxidant enzymes and the accumulation of phenolic compounds were greatest at the highest Al doses, preventing changes in gas exchange and chlorophyll a fluorescence. Starch grain accumulation was noted in plant cells exposed to 200 and 400 μmol Al3+ L−1. Adult E. dysenterica trees also accumulated Al in leaves, bark and seeds. These data suggest that E. dysenterica is tolerant to Al.
The objective was to evaluate the effect of supplementation or not of 10 ppm of ractopamine in diets for swine females in the final stage of finishing, on carcass characteristics and meat quality, 54 animals were used, with an initial average weight of 98 kg (± 0 , 9 kg), distributed in a completely randomized design composed of two treatments, 27 repetitions and one animal per experimental unit. The treatments used were diets without or with supplementation of 10 ppm of ractopamine, for 21 days. The supplementation of ractopamine in diets for female pigs in the final finishing phase influenced the parameters of carcass characteristics and meat quality of the animals. Significant effects were observed (P <0.05) for all evaluated carcass characteristics, except for carcass yield and meat quality: hot and cooled straight carcass, loss of carcass on cooling, lean meat in the carcass, water loss by dripping, shear force on day 7 and water loss by cooking on day 14, there was no effect (P> 0.05) for water loss by cooking on days 1 and 7 and shear force on day 14. With the addition of 10 ppm of ractopamine in the diet of the finishing female pigs for 21 days, it obtained influence on the meat quality, providing better parameters of carcass characteristics, with higher yield of lean meat in the carcass.
Measures of the apparent electrical conductivity (ECa) of soil are used in many studies as indicators of spatial variability in physicochemical characteristics of production fields. Based on these measures, management zones (MZs) are delineated to improve agricultural management. However, these measures include outliers. The presence or incorrect identification and exclusion of outliers affect the variogram function and result in unreliable parameter estimates. Thus, the aim of this study was to model ECa data with outliers using methods based on robust approximation theory and model-based geostatistics to delineate MZs. Robust estimators developed by Cressie-Hawkins, Genton and MAD Dowd were tested. The Cressie-Hawkins semivariance estimator was selected, followed by the semivariogram cubic fit using Akaike information criterion (AIC). The robust kriging with an external drift plug-in was applied to fitted estimates, and the fuzzy k-means classifier was applied to the resulting ECa kriging map. Models with multiple MZs were evaluated using fuzzy k-means, and a map with two MZs was selected based on the fuzzy performance index (FPI), modified partition entropy (MPE) and Fukuyama-Sugeno and Xie-Beni indices. The defined MZs were validated based on differences between the ECa means using mixed linear models. The independent errors model was chosen for validation based on its AIC value. Thus, the results demonstrate that it is possible to delineate an MZ map without outlier exclusion, evidencing the efficacy of this methodology. DELINEAMENTO DE ZONAS HOMOGÊNEAS PORGEOESTATÍSTICA BASEADA EM MODELOS ROBUSTA À OUTLIERS RESUMO -Diversas pesquisas utilizam medidas de condutividade elétrica aparente do solo (CEa) como indicador da variabilidade espacial de atributos físico-químicos existentes no campo de produção. Com base nestas medidas, zonas de manejo (ZM) são delineadas para aperfeiçoamento da gestão agrícola. Entretanto, estas amostras têm apresentado presença de outliers. Todavia, a presença ou incorreta detecção e exclusão de outliers altera o formato do variograma, exibindo estimativas não fidedignas para os seus parâmetros. Dessa forma, objetivou-se nesta pesquisa, tratar dados amostrais da CEa por meio de métodos robustos à presença de outliers, fundamentados na teoria de aproximações robusta e na geoestatística baseada em modelos, para o delineamento de ZM. Assim, estimadores robustos de Cressie Hawkins, Genton"s e MAD Dowd foram avaliados. Nesta avaliação, selecionou-se o estimador de semivariância de Cressie Hawkins. E na sequência, optou-se pelo ajuste cúbico do semivariograma via Critério de Informação de Akaike (AIC). As estimativas obtidas com este ajuste foram aplicadas na plug-in robusto de krigagem. E coerentemente o mapa de krigagem da CEa obtido foi utilizado no classificador fuzzy k-means. Com uso do fuzzy k-means, diferentes ZM foram avaliadas, selecionando-se o mapa com duas ZM por meio dos índices FPI, MPE, Fukuyama-Sugeno e xie beni. As ZM estabelecidas foram validadas quanto as suas diferenças ...
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