Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 396 )

2018 ( 568 )

2017 ( 573 )

2016 ( 823 )

Custom range...

Search Results: 1 - 10 of 355753 matches for " Paulo Sávio;Rodrigues "
All listed articles are free for downloading (OA Articles)
Page 1 /355753
Display every page Item
Fun??es de covariancia para produ??o de leite no dia do controle em bovinos Gir leiteiro
Pereira, Rodrigo Junqueira;Lopes, Paulo Sávio;Verneque, Rui da Silva;Santana Júnior, Mário Luiz;Lagrotta, Marcos Rodrigues;Torres, Robledo de Almeida;
Pesquisa Agropecuária Brasileira , 2010, DOI: 10.1590/S0100-204X2010001100011
Abstract: the objective of this work was to estimate covariance functions for test-day milk yield (tdmy). twenty-seven thousand tdmy records of 3,362 first lactations of gir cows calving between 1990 and 2007 were analyzed. the tdmy data were grouped in 20 biweekly classes, analyzed by random regression models, whose random, additive-genetic and permanent environment effects were fitted by wilmink's (w) or ali & schaeffer's (as) functions. the residual variance (vr) modelling was fitted by 1, 4, 6, or 10 classes. the heritability estimates for tdmy varied from 0.12 to 0.32 for the as function, and from 0.09 to 0.33 for w function, and were larger in the begining of the lactation period. the genetic correlations decreased from near unity, among adjacent tdmy values, to negative values between the first and the two last quarters of lactation. the model using the as function with four vr classes, is a parsimonious option for the tdmy fitting of gir cows in brazil.
Obtaining high purity silica from rice hulls
Silva Júnior, José da;Cunha, Carlo R. da;Carvalho, Flávio L. S. de;Rodrigues Filho, Ubirajara P.;Oliveira, Paulo R.;Silva, Marcos A. Segatto;
Química Nova , 2010, DOI: 10.1590/S0100-40422010000400005
Abstract: many routes for extracting silica from rice hulls are based on direct calcining. these methods, though, often produce silica contaminated with inorganic impurities. this work presents the study of a strategy for obtaining silica from rice hulls with a purity level adequate for applications in electronics. the technique is based on two leaching steps, using respectively aqua regia and piranha solutions, which extract the organic matrix and inorganic impurities. the material was characterized by fourier-transform infrared spectroscopy (ftir), powder x-ray diffraction (xrd), x-ray fluorescence (xrf), scanning electron microscopy (sem), particle size analysis by laser diffraction (lpsa) and thermal analysis.
Flutua??o populacional de moscas-das-frutas (Diptera: Tephritidae) associadas a variedades de manga no município de José de Freitas-Piauí
Feitosa, Sávio Silveira;Silva, Paulo Roberto Ramalho;Pádua, Luiz Evaldo de Moura;Carvalho, Eulália Maria Sousa;Paz, Jean Kelson da Silva;Paiva, David Rodrigues de;
Revista Brasileira de Fruticultura , 2008, DOI: 10.1590/S0100-29452008000100021
Abstract: piaui has a considerable mango area, being a great producer of this fruit. however, the presence of plagues like the fruit flies has provoked great impacts in the production chain, so these insects are part of a responsible group of great economic damages in mango tree culture. the knowledge of the population dynamics and the highest occurrence period of specific insect species of economic importance are indispensable requirement to establish an efficient and rational control. the purpose of the present work was to register the population dynamics of the fruit fly species associated to the mango varieties, as well as correlating the fly occurrence with the monthly averages of temperature, precipitation and relative humidity, and evaluate the food baits used to capture the insects. the research was done from june, 2004 to may, 2005, in mango commercial orchards (mangifera indica l.-anacardiaceae), with tommy atkins, keitt, kent and palmer varieties, located in josé de freitas-piauí-brazil, latitude 04o50's and longitude 42o41'w. anastrepha obliqua and anastrepha serpentina are the predominant fruit fly species in the mango crop.
Paternity in Brazilian goats through the use of DNA microsatellites
Araújo, Adriana Mello de;Guimar?es, Simone Eliza Facioni;Pereira, Carmen Silva;Lopes, Paulo Sávio;Rodrigues, Marcelo Teixeira;Machado, Théa Mírian Medeiros;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010000500010
Abstract: a total of 292 animals from three breeds (alpine and saanen dairy breeds, and the brazilian naturalized breed moxotó) were genotyped, comprising 276 paternity cases. statistical analyses were carried out by using tfpga and cervus programs. heterozygosis ranged from 0.542 (ilsts005) to 0.825 (inra006), with an average of 0.717 for all loci. polymorphic information content (pic) was 0.676 and 0.542, and combined exclusion probabilities (ep) were 0.999591 and 0.988375 for known and unknown maternal genotypes, respectively. the microsatellite system reveals 10% of paternity misidentification in evaluated registers.
Estima??o de parametros genéticos em caprinos leiteiros por meio de análise de regress?o aleatória utilizando-se a Amostragem de Gibbs
Assis, Giselle Mariano Lessa de;Albuquerque, Lucia Galv?o de;Sarmento, José Lindenberg Rocha;Carneiro Júnior, José Marques;Lopes, Paulo Sávio;Rodrigues, Marcelo Teixeira;
Revista Brasileira de Zootecnia , 2006, DOI: 10.1590/S1516-35982006000300011
Abstract: random regression models were used to estimate genetic parameters for test-day milk yield (pldc) of alpine dairy goats, implemented by bayesian methods with gibbs sampling. the estimates were compared with those obtained by random regression analysis, using reml. heritability estimates obtained by bayesian analysis ranged from 0.18 to 0.37, while those obtained by reml ranged from 0.09 to 0.32. genetic correlations between yields of close test days approached the unit, but decreased gradually as the interval between test days increased. results indicated that random regression models are appropriate to model the covariance structure of pldc and to predict genetic gains and select animals along the lactation trajectory of dairy goats. results obtained by bayesian and reml approaches were similar, although genetic variance and heritability estimates were slightly higher with bayesian methods.
Modelos de regress?o aleatória na avalia??o da produ??o de leite em cabras da ra?a Saanen
Menezes, Gilberto Romeiro de Oliveira;Torres, Robledo de Almeida;Sarmento, José Lindenberg Rocha;Rodrigues, Marcelo Teixeira;Brito, Luiz Fernando;Lopes, Paulo Sávio;Silva, Felipe Gomes da;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000700018
Abstract: it was used 10,238 weekly test day records from 388 first lactations of saanen goats with the objective of comparing random regression models (rrm). firstly, it was compared five models, whose exponential terms of wilmink function assumed the following values: -0.0350; -0.0500; -0.0565; -0.0680 and -0.1000 (w0350, w0500, w0565, w0680 and w1000, respectively) by considering homogeneity of residual variance over the lactation period. the value -0.0500 was kept in the model w0500 whereas models w0350, w0565, w0680 and w1000 used values -0.0350; -0.0565; -0.0680 and -0.1000, respectively, replacing the value -0.0500, proposed by the original model used in dairy cattle. after choosing the best model according to ln l, homogeneity and heterogeneity for residual variance: homogeneity, two classes, three classes, four classes, five classes and six classes along the lactation were evaluated by using aic, bic and ln l criteria. according to criterion used, w0350 presents the best fit among the evaluated models. with regard to residual variance, the use of six classes over lactation is indicated by aic, bic, ln l and likelihood ratio test. heritability estimates over lactation, for the best model, ranges from 0.07 (2nd lactation week) to 0.25 (20th lactation week).
Parametros genéticos de características reprodutivas de touros e vacas Gir leiteiro
Santana Júnior, Mário Luiz;Lopes, Paulo Sávio;Verneque, Rui da Silva;Pereira, Rodrigo Junqueira;Lagrotta, Marcos Rodrigues;Peixoto, Maria Gabriela Campolina Diniz;
Revista Brasileira de Zootecnia , 2010, DOI: 10.1590/S1516-35982010000800013
Abstract: this work aimed to estimate genetic parameters for age at first calving, scrotal circumference, and seminal traits, and to evaluate genetic trend for age at first calving for dairy gyr breed animals by analyzing data of 7,055 females and 97 males from several brazilian herds. covariance components were estimated by using the restricted maximum likelihood method under animal model in univariate analyses. the model for seminal traits included the company-year-season of semen collection fixed effects, age at the collection as a covariate, linear and quadratic effects. for scrotal circumference, it was included year of birth, age class at measurement, and insemination company fixed effects. for age at first calving, it was included herd-year-season of birth fixed effects and animal and residual random effects. the heritabilities for scrotal circumference and age at first calving were, respectively, 0.37 and 0.22. the genetic trend of age at first calving was significant, with estimated value of -0.018 month/year and it shows that genetic progress in this trait practically did not occur over the studied years. the genetic correlations from bivariate analyses among scrotal circumference with volume, concentration, vigor, motility, major, minor, and total defects, number of doses, total number of feasible spermatozoid and age at first calving were 0.33, 0.22, 0.91, 0.86, -0.07, -0.03, -0.04, 0.30, 0.23 and -0.37, respectively. these results suggest improvements in reproductive efficiency of females when they are used in herds with bulls with greater scrotal circumference.
Compara??o de modelos de regress?o aleatória para estima??o de parametros genéticos em caprinos leiteiros
Sarmento, José Lindenberg Rocha;Albuquerque, Lucia Galv?o de;Torres, Robledo de Almeida;Rodrigues, Marcelo Teixeira;Lopes, Paulo Sávio;Reis Filho, Jo?o Cruz;
Revista Brasileira de Zootecnia , 2008, DOI: 10.1590/S1516-35982008001000011
Abstract: random regression and legendre polynomial (lp) of different orders were used for modeling the genetic, permanent environmental and residual variances of test day milk yield in dairy goats. the models included the fixed effects of contemporary group, age of dam at kidding as a covariate and the fixed regression of lp for the average lactation curve and the additive genetic, permanent environmental and residual as random effects. according to the values of the logarithm of the likelihood function, aic and bic using higher orders of lp (fifth order for the genetic effect and seventh order for the permanent environmental effect) improved the fitting of the models. the model with four classes of residual variances provided the best fit. the eigenvalues of the (co)variances matrix among the regression coefficients suggested the possibility of reducing the dimension of the models. the estimates of genetic variances and genetic and permanent environmental correlations for test day milk yields obtained from polynomials of higher orders are not biologically expected. the lp of fifth order for the addictive genetic and seventh order for the permanent environmental effects was the best fitted model. however, a lp of fourth order for the addictive genetic and of sixth order for the permanent environmental effects may be considered as a more parsimonious model for the estimation of variances of test day milk yield in dairy goats, by random regression.
Avalia??o genética de caprinos da ra?a Alpina utilizando-se a produ??o de leite no dia do controle
Sarmento, José Lindenberg Rocha;Reis Filho, Jo?o Cruz;Albuquerque, Lucia Galv?o de;Lopes, Paulo Sávio;Rodrigues, Marcelo Teixeira;
Revista Brasileira de Zootecnia , 2006, DOI: 10.1590/S1516-35982006000200015
Abstract: data consisting of 26,389 individual test day milk yield from 825 lactations of 356 parda alpina goats, recorded from 1997 to 2004, were used to estimate genetic parameters and to predict breeding values for test day (pldc) and accumulated (pac) milk yields. the model for pldc included the fixed effects of contemporary group (year-month of test), age of dam at kidding as covariate, and additive genetic, permanent environment and residual random effects. the model for pac included the same random effects used for pldc and the fixed effects of contemporary group (year-month of kidding) and the covariates age of dam at kidding and lactation length. larger heritability estimates for milk yield in the intermediary test days indicate possibility of selection response. rank correlation between breeding values for milk yield up to 305 days and intermediary pldc were larger than those on early and late lactation. despite the high rank correlation, changes in ranking of bucks for milk yield up to 305 days were observed when selection was based on pldc at 90 days. selection based on pldc and pac in middle lactation may be used as a selection criterion in substitution for milk yield up to 305 days.
Estima??o de parametros genéticos para produ??o de leite de cabras da ra?a Alpina
Breda, Fernanda Cristina;Albuquerque, Lucia Galv?o;Yamaki, Marcos;Reis Filho, Jo?o Cruz;Sarmento, José Lindenberg Rocha;Lopes, Paulo Sávio;Rodrigues, Marcelo Teixeira;
Revista Brasileira de Zootecnia , 2006, DOI: 10.1590/S1516-35982006000200009
Abstract: data consisting of 9,374 test day milk yield records from 302 first lactations of alpina goats were analyzed by random regression models using the wilmink and ali and schaeffer functions and legendre orthogonal polynomials of third and fifth orders. models including animal additive genetic, permanent environmental and homogeneous or heterogeneous (three or four classes) residual random effects were compared by akaike information criterion (aic), schwarz bayesian information criterion (bic), likelihood ratio test (ln l), phenotypic, permanent environmental, genetic and residual variances and by heritability estimates. according to aic, bic and ln l, legendre orthogonal polynomial of fifth order with three or four residual classes and ali and schaeffer function with four residual classes were the best fitting models. these models differed by the partition of phenotypic, permanent environmental, genetic and residual variance estimates in the beginning and in the end of the lactation period. genetic correlation estimates between milk yields in the beginning and in the end of lactation obtained by ali and schaeffer function were negative. legendre polynomial of fifth order assuming heterogeneous residual variance was the best fitting model for test day milk yield of alpina goats.
Page 1 /355753
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.