118 resultados para Generalized Logistic Model
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Há poucos dados sistematizados sobre eventos adversos da vacina contra influenza no Brasil. Este trabalho visou identificar estes eventos em população acima de 60 anos que compareceu à Campanha Nacional de Vacinação do Idoso, em Distrito de Campinas, SP, em 2000. Foi realizada entrevista para relato de sintomas gerais e locais, com nexo temporal após a aplicação do imunobiológico, em amostra aleatória sistemática da população (n=206). Registraram-se 20,38% (IC 14,87-25,88) dos indivíduos com um ou mais sintomas, sendo a dor no local da vacina, a mais freqüente 12,6% (IC 8,09-17,15). Ajustou-se um modelo de regressão logística múltipla, tendo como variável dependente, a ocorrência de pelo menos um evento adverso. A variável independente que se mostrou associada às reações adversas foi o sexo (feminino) (OR=5,89 e IC 2,08-16,68). Os achados deste estudo reafirmam a pequena reatogenicidade da vacina contra a influenza.
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Weight-age and hip height-age relations of Nellore calves, from birth to 10 months old were fitted using a logistic model including sex and year of birth as fixed effects. Calves and their dams were reared on natural pasture using continuous grazing system. The crude protein content and total digestible nutrients were analyzed for pasture selected by the animals. The weights of the calves were adjusted to 205 days and 365 days. There were no significant effects of sex and birth year on the growth curve parameters, but there were significant effects of sex on hip height. The average weight (a parameter) at 10 months of age was 170 kg and the inflection point was observed at 93.5 days old. When weight-age and hip height-age curves were combined in the same graph, the intersection occurred at 142 days. The number of days to gain 160 kg from birth to 205 days of age (adjusted) and number of days to gain 240 kg from 205 days to slaughter was different between the birth years, which were probably due to the quality of the natural pastures. It is necessary to implement nutritional management strategies such as high quality pasture and/or feeding supplementation for calves once they reach three months of age.
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The objective of this study was to evaluate the factors that may affect conception rates (CR) following artificial insemination (AI) or embryo transfer (ET) in lactating Holstein cows. Estrous cycling cows producing 33.1 +/- 7.2 kg of milk/d received PGF(2 alpha) injections and were assigned randomly to 1 of 2 groups (AI or ET). Cows detected in estrus (n = 387) between 48 and 96 h after the PGF2a injection received AI (n = 227) 12 h after detection of estrus or ET (n = 160) 6 to 8 d later (1 fresh embryo, grade 1 or 2, produced from nonlactating cows). Pregnancy was diagnosed at 28 and 42 d after estrus, and embryonic loss occurred when a cow was pregnant on d 28 but not pregnant on d 42. Ovulation, conception, and embryonic loss were analyzed by a logistic model to evaluate the effects of covariates [days in milk (DIM), milk yield, body temperature (BT) at d 7 and 14 post-AI, and serum concentration of progesterone (P4) at d 7 and 14 post-AI] on the probability of success. The first analysis included all cows that were detected in estrus. The CR of AI and ET were different on d 28 (AI, 32.6% vs. ET, 49.4%) and 42 (AI, 29.1% vs. ET, 38.8%) and were negatively influenced by high BT (d 7) and DIM. The second analysis included only cows with a corpus luteum on d 7. Ovulation rate was 84.8% and was only negatively affected by DIM. Conception rates of AI and ET were different on d 28 (AI, 37.9% vs. ET, 59.4%) and 42 (AI, 33.8% vs. ET, 46.6%) and were negatively influenced by high BT (d 7). The third analysis included only ovulating cows that were 7 d postestrus. Conception rates of AI and ET were different on d 28 (AI, 37.5% vs. ET, 63.2%) and 42 (AI, 31.7% vs. ET, 51.7%) and were negatively influenced by high BT (d 7). There was a positive effect of serum concentration of P4 and a negative effect of milk production on the probability of conception for the AI group but not for the ET group. The fourth analysis was embryonic loss (AI, 10.8% vs. ET, 21.5%). The transfer of fresh embryos is an important tool to increase the probability of conception of lactating Holstein cows because it can bypass the negative effects of milk production and low P4 on the early embryo. The superiority of ET vs. AI is more evident in high-producing cows. High BT measured on d 7 had a negative effect on CR and embryonic retention.
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In this article, proportional hazards and logistic models for grouped survival data were extended to incorporate time-dependent covariates. The extension was motivated by a forestry experiment designed to compare five different water stresses in Eucalyptus grandis seedlings. The response was the seedling lifetime. The data set was grouped since there were just three occasions in which the seedlings was visited by the researcher. In each of these occasions also the shoot height was measured and therefore it is a time-dependent covariate. Both extended models were used in this example, and the results were very similar.
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Dados de crescimento e reprodução de 573 vacas da raça Guzerá, nascidas entre 1961 e 1985, na Fazenda Canoas, em Curvelo, MG, foram analisados com o objetivo de estabelecer um padrão médio de crescimento, mediante o uso de um modelo matemático que se ajuste adequadamente aos dados. Os modelos Brody, Bertalanffy, Logístico, Gompertz e Richards foram ajustados aos dados de peso/idade, coletados até 1992, e comparados quanto à qualidade de ajustamento. Os pesos assintóticos e as taxas de maturidade estimadas foram, respectivamente: para o modelo Brody, 464,49 e 0,046; para o Bertalanffy, 453,18 e 0,065; para o Logístico, 447,05 e 0,085; para o Gompertz, 449,89 e 0,075, e para o Richards, 458,26 e 0,055. O modelo Richards apresentou dificuldades computacionais para ajustamento aos dados. Os outros modelos se revelaram adequados para descrever o crescimento nesses animais, apresentando pequenas variações na qualidade de ajustamento, de acordo com os critérios utilizados. O modelo Bertalanffy foi escolhido para representar a curva média de crescimento dos animais, por apresentar um ajustamento superior no conjunto dos critérios.
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PURPOSE:To assess whether late introduction of a specific COX-2 inhibitor (Meloxicam) can treat and/or prevent the progression of tumors in the stomach of rats submitted to duodenogastric reflux. METHODS: Seventy five male Wistar rats, weighing 150 grams, were submitted to the induction of duodenogastric reflux through the pylorus. At 36 weeks of follow-up were established three experimental groups: DGR36 sacrificed immediately, DGR54 and DGR54MLX both sacrificed at 54th week of follow-up . The animals of the latter group were fed with a rat chow premixed with Meloxicam (2.0 mg/ kg feed; 0.3 mg / kg bw / day) and the other two with standard rat chow. The lesions found in the pyloric mucosa and gastrojejunal anastomosis were analyzed macroscopically and histologically. For statistical analysis was adjusted a generalized linear model assuming a binomial distribution with LOGIT link function. RESULTS: No significant differences were found when comparing the incidences of benign tumor lesions (Adenomatous Hyperplasia), p=0.4915, or malignant (Mucinous Adenocarcinoma), p=0.2731, among groups. CONCLUSION: Late introduction of specific COX-2 inhibitor (Meloxicam) did not treat and was not able to prevent the progression of tumoral lesions induced by duodenogastric reflux in the rat stomachs.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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No presente estudo, ajustou-se um modelo de regressão logística para prever a probabilidade de óbito de cães acometidos por gastroenterite hemorrágica. O modelo Logístico é recomendado para variáveis-resposta dicotômicas em estudo de Coorte. Registraram-se 176 animais censitariamente atendidos com gastroenterite hemorrágica em quatro clínicas veterinárias da cidade de Lavras, sul de Minas Gerais, entre os anos de 1992 e 1999. Após terem sido selecionadas por meio do teste de Pearson ou teste exato de Fisher, ajustou-se o modelo considerando-se as variáveis sexo, idade, diárias de internação e número de atendimentos. A estimação dos parâmetros foi feita pelo método da máxima verossimilhança. Conclui-se que quando os cães acometidos por gastroenterite hemorrágica são atendidos apenas uma vez, aqueles com idade superior a 6 meses possuem 15,45 vezes mais chances de morrerem (P<0,05) do que aqueles com menos de 6 meses de idade. Quando os animais que apresentam a enfermidade possuem mais de 6 meses de idade, a chance de morrerem, se forem atendidos apenas uma vez, é 20,251 vezes maior (P<0,05) do que se recebessem de 2 a 7 atendimentos.
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We derive Virasoro constraints for the zero momentum part of the QCD-like partition functions in the sector of topological charge v. The constraints depend on the topological charge only through the combination N-f +betav/2 where the value of the Dyson index beta is determined by the reality type of the fermions. This duality between flavor and topology is inherited by the small-mass expansion of the partition function and all spectral sum rules of inverse powers of the eigenvalues of the Dirac operator. For the special case beta =2 but arbitrary topological charge the Virasoro constraints are solved uniquely by a generalized Kontsevich model with the potential V(X) = 1/X.
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Rheological properties of rehydrated prunes were obtained applying compression-relaxation tests by using a Texture Analyzer TAXT2i. A mathematical development was adopted to determine the stress and area, along the deformation. Experimental data of stress versus time was fitted by using three different rheological models: generalized Maxwell, Normand & Peleg and Maxwell. Results showed that generalized Maxwell model can be used to describe the viscoelastic behavior of the samples. The rheological parameters obtained indicated that prunes exhibited elastic behavior more pronounced at low moisture content and drying air temperature. At high moisture content and temperature the sample became a more viscous and less rigid.
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The viscoelastic behavior of dried persimmons at different air-drying temperatures and velocities was evaluated. Air temperatures and velocities were varied according to a second-order central composite design, with temperature ranging from 40degreesC to 70degreesC and air velocity from 0.8 to 2.0 m/s. After drying, persimmons were equilibrated at four different water activities: 0.432, 0.576, 0.625 and 0.751. The rheological behavior of dried and conditioned persimmons was studied under uniaxial compression-relaxation tests. Three different rheological models were fitted to the experimental relaxation curves: Maxwell, Generalized Maxwell and Peleg and Normand. Based on the root mean square of residuals, the Generalized Maxwell model showed the best fit and a regression analysis was applied to obtain response surfaces for the model parameters. The dependence of the rheological properties on water activity was also analysed. Results showed that only the linear effect of air temperature was significant at a 5% level on the equilibrium stress and relaxation times. In a general way, these parameters increased with increasing air temperature and decreasing water activity. (C) 2004 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Hearing loss and tinnitus impact the lives of workers in every instance of their lives. Aim: this paper aims to investigate the existence of a dose-response relationship between hearing loss and tinnitus by determining whether higher levels of hearing loss can be associated with increased tinnitus-related discomfort. Materials and method: this cross-sectional case study assessed 284 workers exposed to occupational noise through pure tone audiometry. Test results were categorized as defined by Merluzzi. Individuals complaining of tinnitus answered the adapted and validated Brazilian Portuguese version of the Tinnitus Handicap Inventory. A generalized linear model was adjusted for binomial data to test the interaction between these factors. Results: over 60% of the ears analyzed had hearing loss, while more than 46% of them had tinnitus. Tinnitus prevalence and risk rates increased as pure tone audiometry results got worse. The association between both, considering all hearing loss degrees, was statistically significant. Conclusion: the results point to a statistical association between hearing loss and tinnitus; the greater the hearing loss, the greater the discomfort introduced by tinnitus. 2009 © Revista Brasileira de Otorrinolaringologia.
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This paper presents a general modeling approach to investigate and to predict measurement errors in active energy meters both induction and electronic types. The measurement error modeling is based on Generalized Additive Model (GAM), Ridge Regression method and experimental results of meter provided by a measurement system. The measurement system provides a database of 26 pairs of test waveforms captured in a real electrical distribution system, with different load characteristics (industrial, commercial, agricultural, and residential), covering different harmonic distortions, and balanced and unbalanced voltage conditions. In order to illustrate the proposed approach, the measurement error models are discussed and several results, which are derived from experimental tests, are presented in the form of three-dimensional graphs, and generalized as error equations. © 2009 IEEE.