844 resultados para partial least square


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O perímetro escrotal (PE) de 202 touros jovens da raça Nelore, sem experiência sexual prévia, classificados pela Associação Brasileira de Criadores de Zebu como superiores ou elite, foi medido aos 7, 12, 18 e 28 meses de idade, aproximadamente. Após a última medição, eles foram submetidos ao teste de libido e procedeu-se à colheita de sêmen por eletroejaculação, seguida de avaliação andrológica. As medidas do PE aos 7, 12, 18 e 28 meses foram de 18,30; 22,29; 27,54 e 33,26cm, respectivamente. Os coeficientes de correlação simples entre estas medidas variaram de 0,35 a 0,53. O coeficiente de correlação entre PE aos 28 meses e peso corporal na mesma idade foi de 0,43. A correlação entre a nota da libido e o perímetro escrotal medido aos l8 meses foi de 0,15 e entre aquela e o perímetro escrotal aos 28 meses foi de 0,13. Observou-se elevado crescimento do perímetro escrotal entre o 7º e 18º meses de idade. Utilizou-se o método de quadrados mínimos para analisar a libido, incluindo ano de nascimento como efeito fixo e como covariáveis os efeitos lineares da idade e peso no momento da avaliação e medidas de perímetro escrotal aos 7, l2, l8 e 28 meses. Cada covariável foi retida de forma seqüencial obtendo-se vários modelos de análises e as somas de quadrados foram decompostas de forma seqüencial e parcial. O ano de nascimento, a idade e o perímetro escrotal aos 18 meses de idade afetaram significativamente a libido. Os coeficientes de correlação entre a libido e concentração espermática, motilidade, peso e idade do animal no momento da avaliação foram de 0,34, 0,l6, 0,38 e 0,35, respectivamente.

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Esta pesquisa foi conduzida com o objetivo de avaliar o efeito da endogamia e suas possíveis influências sobre o crescimento de bovinos de corte. Foram utilizadas 27.406 observações de peso à desmama, padronizado aos 205 dias (PD), e 14.317 informações de peso ao ano, padronizado aos 365 dias (PA), de animais da raça Gir, no período de 1970 a 1995. As análises foram feitas pelo método dos quadrados mínimos, incluindo-se o efeito aleatório de grupo contemporâneo e os efeitos fixos de geração (discreto), idade da vaca ao parto e taxa de endogamia do bezerro e da vaca como variáveis contínuas, considerando-se os efeitos linear e quadrático. Apenas 11,65% das vacas, 19,84% dos touros e 9,23% dos bezerros da raça Gir estudados apresentaram algum grau de endogamia e as estimativas das médias de endogamia foram de pequena magnitude, constatando-se valores de 1,04; 0,96; e 1,66% para vacas, touros e bezerros, respectivamente. O efeito da endogamia do animal foi significativo e quadrático para as duas características estudadas. Os resultados mostraram depressão endogâmica para ambas as características (PD e PA). Recomenda-se evitar os acasalamentos, intencionalmente, endogâmicos e monitorar os acasalamentos com base no parentesco entre os indivíduos, visando manter baixas as taxas de endogamia.

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Neste trabalho foram estudados os efeitos de idade e peso sobre o perímetro escrotal (PE) de touros jovens da raça Nelore e estimados os fatores de correção (FC) do PE para esses efeitos. As informações utilizadas pertencem aos Registros de Produção da Associação Paraguaia dos Criadores de Nelore, obtidos entre 1986 e 1997, de 110 criatórios, totalizando 7458 observações. Os coeficientes de regressão que permitiram o cálculo dos FCs para o PE foram estimados pelo método dos quadrados mínimos, empregando-se um modelo que considerou o grupo contemporâneo (animais nascidos no mesmo ano, estação, rebanho, avaliados na mesma data e do mesmo grupo de manejo alimentar na desmama e no sobreano), o efeito linear da idade em dias e os efeitos linear e quadrático do peso aos 570 dias de idade (P570). O efeito da idade sobre o PE foi igual a 0,0383(±0,0024) cm/dia e do P570 sobre o PE corrigido para essa idade, 0,0708(±0,0049) cm/kg, efeito linear, e -0,0000413(±0,0000074) cm/kg², efeito quadrático. A idade e o peso do animal foram importantes fontes de variação a serem removidas do PE, como indicativo da precocidade sexual de touros de sobreano.

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The present work has as objective to present a method of project and implementation of controllers PID, based on industrial instrumentation. An automatic system of auto-tunning of controllers PID will be presented, for systems of first and second order. The software presented in this work is applied in controlled plants by PID controllers implemented in a CLP. Software is applied to make the auto-tunning of the parameters of controller PID of plants that need this tunning. Software presents two stages, the first one is the stage of identification of the system using the least square recursive algorithm and the second is the stage of project of the parameters of controller PID using the root locus algorithm. An important fact of this work is the use of industrial instrumentation for the accomplishment of the experiments. The experiments had been carried through in controlled real plants for controllers PID implemented in the CLP. Thus has not only one resulted obtained with theoreticians experiments made with computational programs, and yes resulted obtained of real systems. The experiments had shown good results gotten with developed software

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The control, automation and optimization areas help to improve the processes used by industry. They contribute to a fast production line, improving the products quality and reducing the manufacturing costs. Didatic plants are good tools for research in these areas, providing a direct contact with some industrial equipaments. Given these capabilities, the main goal of this work is to model and control a didactic plant, which is a level and flow process control system with an industrial instrumentation. With a model it is possible to build a simulator for the plant that allows studies about its behaviour, without any of the real processes operational costs, like experiments with controllers. They can be tested several times before its application in a real process. Among the several types of controllers, it was used adaptive controllers, mainly the Direct Self-Tuning Regulators (DSTR) with Integral Action and the Gain Scheduling (GS). The DSTR was based on Pole-Placement design and use the Recursive Least Square to calculate the controller parameters. The characteristics of an adaptive system was very worth to guarantee a good performance when the controller was applied to the plant

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GPS active networks are more and more used in geodetic surveying and scientific experiments, as water vapor monitoring in the atmosphere and lithosphere plate movement. Among the methods of GPS positioning, Precise Point Positioning (PPP) has provided very good results. A characteristic of PPP is related to the modeling and/or estimation of the errors involved in this method. The accuracy obtained for the coordinates can reach few millimeters. Seasonal effects can affect such accuracy if they are not consistent treated during the data processing. Coordinates time series analyses have been realized using Fourier or Harmonics spectral analyses, wavelets, least squares estimation among others. An approach is presented in this paper aiming to investigate the seasonal effects included in the stations coordinates time series. Experiments were carried out using data from stations Manaus (NAUS) and Fortaleza (BRFT) which belong to the Brazilian Continuous GPS Network (RBMC). The coordinates of these stations were estimated daily using PPP and were analyzed through wavelets for identification of the periods of the seasonal effects (annual and semi-annual) in each time series. These effects were removed by means of a filtering process applied in the series via the least squares adjustment (LSQ) of a periodic function. The results showed that the combination of these two mathematical tools, wavelets and LSQ, is an interesting and efficient technique for removal of seasonal effects in time series.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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In this work we used chemometric tools to classify and quantify the protein content in samples of milk powder. We applied the NIR diffuse reflectance spectroscopy combined with multivariate techniques. First, we carried out an exploratory method of samples by principal component analysis (PCA), then the classification of independent modeling of class analogy (SIMCA). Thus it became possible to classify the samples that were grouped by similarities in their composition. Finally, the techniques of partial least squares regression (PLS) and principal components regression (PCR) allowed the quantification of protein content in samples of milk powder, compared with the Kjeldahl reference method. A total of 53 samples of milk powder sold in the metropolitan areas of Natal, Salvador and Rio de Janeiro were acquired for analysis, in which after pre-treatment data, there were four models, which were employed for classification and quantification of samples. The methods employed after being assessed and validated showed good performance, good accuracy and reliability of the results, showing that the NIR technique can be a non invasive technique, since it produces no waste and saves time in analyzing the samples

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In this work calibration models were constructed to determine the content of total lipids and moisture in powdered milk samples. For this, used the near-infrared spectroscopy by diffuse reflectance, combined with multivariate calibration. Initially, the spectral data were submitted to correction of multiplicative light scattering (MSC) and Savitzsky-Golay smoothing. Then, the samples were divided into subgroups by application of hierarchical clustering analysis of the classes (HCA) and Ward Linkage criterion. Thus, it became possible to build regression models by partial least squares (PLS) that allowed the calibration and prediction of the content total lipid and moisture, based on the values obtained by the reference methods of Soxhlet and 105 ° C, respectively . Therefore, conclude that the NIR had a good performance for the quantification of samples of powdered milk, mainly by minimizing the analysis time, not destruction of the samples and not waste. Prediction models for determination of total lipids correlated (R) of 0.9955, RMSEP of 0.8952, therefore the average error between the Soxhlet and NIR was ± 0.70%, while the model prediction to content moisture correlated (R) of 0.9184, RMSEP, 0.3778 and error of ± 0.76%

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Aiming to consumer s safety the presence of pathogenic contaminants in foods must be monitored because they are responsible for foodborne outbreaks that depending on the level of contamination can ultimately cause the death of those who consume them. In industry is necessary that this identification be fast and profitable. This study shows the utility and application of near-infrared (NIR) transflectance spectroscopy as an alternative method for the identification and classification of Escherichia coli and Salmonella Enteritidis in commercial fruit pulp (pineapple). Principal Component Analysis (PCA), Independent Modeling of Class Analogy (SIMCA) and Discriminant Analysis Partial Least Squares (PLS-DA) were used in the analysis. It was not possible to obtain total separation between samples using PCA and SIMCA. The PLS-DA showed good performance in prediction capacity reaching 87.5% for E. coli and 88.3% for S. Enteritides, respectively. The best models were obtained for the PLS-DA with second derivative spectra treated with a sensitivity and specificity of 0.87 and 0.83, respectively. These results suggest that the NIR spectroscopy and PLS-DA can be used to discriminate and detect bacteria in the fruit pulp

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The separation methods are reduced applications as a result of the operational costs, the low output and the long time to separate the uids. But, these treatment methods are important because of the need for extraction of unwanted contaminants in the oil production. The water and the concentration of oil in water should be minimal (around 40 to 20 ppm) in order to take it to the sea. Because of the need of primary treatment, the objective of this project is to study and implement algorithms for identification of polynomial NARX (Nonlinear Auto-Regressive with Exogenous Input) models in closed loop, implement a structural identification, and compare strategies using PI control and updated on-line NARX predictive models on a combination of three-phase separator in series with three hydro cyclones batteries. The main goal of this project is to: obtain an optimized process of phase separation that will regulate the system, even in the presence of oil gushes; Show that it is possible to get optimized tunings for controllers analyzing the mesh as a whole, and evaluate and compare the strategies of PI and predictive control applied to the process. To accomplish these goals a simulator was used to represent the three phase separator and hydro cyclones. Algorithms were developed for system identification (NARX) using RLS(Recursive Least Square), along with methods for structure models detection. Predictive Control Algorithms were also implemented with NARX model updated on-line, and optimization algorithms using PSO (Particle Swarm Optimization). This project ends with a comparison of results obtained from the use of PI and predictive controllers (both with optimal state through the algorithm of cloud particles) in the simulated system. Thus, concluding that the performed optimizations make the system less sensitive to external perturbations and when optimized, the two controllers show similar results with the assessment of predictive control somewhat less sensitive to disturbances

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Molecular biology techniques are of help in genetic improvement since they permit the identification, mapping and analysis of polymorphisms of genes encoding proteins that act on metabolic pathways involved in economically interesting traits. The somatotrophic axis, which essentially consists of growth hormone releasing hormone (GHRH), growth hormone (GH), insulin-like growth factors I and II (IGF-I and IGF-II), and their associated binding proteins and receptors (GHRHR, GHR, IGF-IR and IGF-IIR), plays a key role in the metabolism and physiology of mammalian growth. The objectives of the present study were to estimate the allele and genotype frequencies of the IGF-I/SnaBI, IGF-IR/TaqI and GHRH/HaeIII gene polymorphisms in different genetic groups of beef cattle and to determine associations between these polymorphisms and growth and carcass traits. For this purpose, genotyping was performed on 79 Nellore animals, 30 Canchim (5/8 Charolais+3/8 Zebu) animals and 275 crossbred cattle originating from the crosses of Simmental (n=30) and Angus (n=245) sires with Nellore females. In the association studies, traits of interest were analyzed using the GLM procedure of SAS and least square means of the genotypes were compared by the Tukey test. Associations of IGF-I/SnaBI genotypes with body weight and subcutaneous backfat were significant (p < 0.05), and nearly significant for longissimus dorsi area (p=0.06), with the 1313 genotype being favorable compared to the AB genotype. No significant associations were observed between this polymorphism and weight gain or carcass yield (P > 0.05). The IGF-IR/TaqI and GHRH/HaeIII polymorphisms showed no association with production traits. (c) 2004 Elsevier B.V All rights reserved.

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

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

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Foram avaliadas três formas de parcelas experimentais (retangular, uma linha - linear e parcela de uma árvore - STP) em testes clonais de Eucalyptus spp, utilizando-se três experimentos, cada um com 18 clones. Foram usados três modelos de análise (mínimos quadrados ordinários - ANOVA tradicional, modelos mistos com fator clone fixo ou com fator clone aleatório - REML/BLUP). Os dois primeiros modelos apresentaram resultados similares. Com REML/BLUP houve estreitamento das predições em relação às amplitudes obtidas com as médias, e essa redução foi proporcionalmente maior com parcelas retangulares e STP. O ordenamento dos clones também foi similar com esses dois tipos de parcelas. É provável que com parcelas STP haja um balanço compensatório das alocompetições, pois se pode trabalhar com maior número de repetições e menor custo. Portanto, com parcelas STP haverá economia de recursos e sem prejuízos para o Programa de Melhoramento Florestal.