914 resultados para principal component


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This study aimed to evaluate the sediment quality in the estuarine protected area known as Canan,ia-Iguape-Peruibe (CIP-PA), located on the southeastern coast of Brazil. The study was designed considering possible negative effects induced by the city of Canan,ia on the sediment quality of surrounding areas. This evaluation was performed using chemical and ecotoxicological analyses. Sediments were predominantly sandy, with low CaCO3 contents. Amounts of organic matter varied, but higher contents occurred closer to the city, as well as did Fe and Total Recoverable Oils and Greases (TROGs) concentrations. Contamination by Cd and Cu was revealed in some samples, while concentrations of Zn were considered low. Chronic toxicity was detected in all tested sediments and acute toxicity occurred only in sediments collected near the city. The principal component analysis (PCA) revealed an association among Cd, Cu, Fe, TROG, fines, organic matter, CaCO3, and chronic toxicity, whereas acute toxicity was found to be associated with Zn and mud. However, because Zn levels were low, acute toxicity was likely due to a contaminant that was not measured. Results show that there is a broad area within the CIP-PA that is under the influence of mining activities (chronic toxicity, moderate contamination by metals), whereas poorer conditions occur closer to Canan,ia (acute toxicity); thus, the urban area seems to constitute a relevant source of contaminants for the estuarine complex. These results show that contamination is already capable of producing risks for the local aquatic biota, which suggests that the CIP-PA effectiveness in protecting estuarine biota may be threatened.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The objetive of this research was to study the relation among body weight and average daily gain in different ages, using principal components analysis. Data on 1663 birth weight (BW), weaning weight adjusted to 230 days (WW), yearling weight adjusted to 365 days (YW), long yearling weight adjusted to 550 days (LYW), average daily gain from birth to weaning (AGW), average daily gain from weaning to 365 days (AGY) and average daily gain from 365 days weight to 550 day weight (AGL) from crossbred animals, and data on 320 observations of the same traits from straightbreed Nellore animals were analysed. The model included the fixed effects of breed (only crossbred data), contemporary group, and linear and quadratic effects of age at calving. For body weight in different ages, the first principal component contrasted heavier and light animals after birth and explained about 79,0% and 78,0% of the variation for data on crossbred and Nellore animals, respectively. The second principal component compared heavier animals at weaning and yearling weight those at long yearling weight. It explained around 13,5% and 15,5% of the total variation, respectively, for data on F1 and Nellore breed. The major source of variation among animals on the two data set for body weight was due to differences in weight followed by differences in the ages they got those weight. For the traits expressed as average daily gain, the variation among animals was due to differences in birth season, the first principal component explaining about 52,0% of the variation on crossbred animals. This component compared animal with higher AGY with those with higher AGW and AGL. For data on Nellore breed, the first component explain about 56,0% of the total variation and also compared animals with higher AGY with those with higher AGW and AGL.

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The soybean crop is considered a high expression around the world. In plant breeding programs, knowledge of genetic diversity is extremely important and in this context, are frequently used multivariate analyzes. Thus, the aim of the present study was to evaluate the genetic divergence between soybean crosses through multivariate techniques. In total, 16 crosses were evaluated, which were in the F2 generation of inbreeding. The evaluated characteristics were plant height at maturity, height of the first pod, number of branches per plant, number of pods per plant, number of nodes per plant, hundred seed weight, grain yield and oil content. For the analyzes was used Euclidean distance, methods of hierarchical clustering UPGMA and Ward and principal component analysis. Genetic distances estimated using Euclidean distance ranged from 1.24 to 8.13, with the smallest distance observed between crosses C1 and C4, and the greatest distance between the C2 crosses and C6. The methods UPGMA clustering and Ward met crossings in five different groups. The principal component analysis explained 86.2% of the variance contained in the original eight variables with three main components. The APM characters, NV, NR, NN, PG% and oil were the main contributors to genetic divergence among traits. Multivariate techniques were crucial to the analysis of genetic diversity, and the methods of Ward and UPGMA clustering and principal components have consistent results in this way, the simultaneous use of these tools in genetic analysis of crosses is indicated

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Brazilian wines are appreciated by consumers for having fruity odor and taste which are typical from Vitis labrusca cultivars. The rusticity of these cultivars, the winemaking and the physicochemical properties are some of the key factors to obtain a quality beverage. In this context, the aim of this article was to analyze the quality of three white wines from wineries located in northwest region of São Paulo state by determining physicochemical properties and sensory profile. Data were analyzed by statistical tests and by Principal Component Analysis (PCA). It was possible to observe statistical differences (P<0,05) in most physicochemical properties. Furthermore, the PCA showed that the attributes body and color significantly explained the variance of the first and second component, respectively, higlighting the Vitis vinifera wine. Thus the connection between the physicochemical and sensory properties of white wines was important for characterization of these beverages produced in the northwest of São Paulo.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective of this paper is to relate the set of financial ratios that are directly related to the success of public traded companies using a methodological approach and the method of multivariate principal component analysis. This study consists in the use of profitability ratios, debt and liquidity, to define the relationship between financial ratios with the best public traded companies listed in the magazine Exame Melhores e Maiores of 2013. Multivariate analysis was used to reduce the dimensionality of multivariate data, making linear combinations of the original variables (financial ratios) and express the data in principal components that result in new variables that contains much of the original data. As a result, we got the optimal number of five principal components, and both represent 95.6% of the original data. Among of all financial ratios, we can highlight the direct relationship between profitability ratios for the first principal component, and the direct relationship between the liquidity ratios, both inversely related with non-capital participation rates and degree indebtedness to the second principal component

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The knowledge of the structure characteristic of the Organic Matter is important for the understanding of the natural process. In this context aquatic humic substances (principal fraction) were isolated from water sample collected from the two distinct rivers, using procedure recommended for International Humic Substances Society and characterized by elemental analysis, electron paramagnetic resonance and nuclear magnetic resonance (13C NMR). The results were interpreted using principal component analysis (PCA) and the statistical analyses showed different in the structural characteristics of the aquatic humic substances studied.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Pós-graduação em Agronomia (Genética e Melhoramento de Plantas) - FCAV

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Pós-graduação em Ciências Ambientais - Sorocaba