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Search Results: 1 - 10 of 22491 matches for " Paulo Justiniano;Meyer "
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Contagem de células somáticas e produ??o de leite em vacas holandesas de alta produ??o
Coldebella, Arlei;Machado, Paulo Fernando;Demétrio, Clarice Garcia Borges;Ribeiro Júnior, Paulo Justiniano;Corassin, Carlos Humberto;Meyer, Paula Marques;Cassoli, Laerte Dagher;
Pesquisa Agropecuária Brasileira , 2003, DOI: 10.1590/S0100-204X2003001200012
Abstract: the goal of this paper was to evaluate if losses in milk yield due to increase in somatic cells count are proportional or independent of the level of production. a total of 7,756 observations, monthly collected from a single herd from september/2000 up to june/2002, were used. the lactation curve was modeled by the incomplete gamma function, considering the effects of lactation order, calving season, peripartum disorder incidence and body condition score at calving. somatic cells count was added to the model as a multiplicative factor, representing relative losses, and as an additive factor, representing absolute losses. the best model was chosen based on the information criteria of schwarz (bic). the losses are absolute, becoming evident from 14,270 cells/ml, and they are 184 and 869 g/day for each increase of one unit in the natural logarithm scale, starting from that somatic cells count, for primiparous and multiparous cows, respectively.
Contagem de células somáticas e produ??o de leite em vacas holandesas confinadas
Coldebella, Arlei;Machado, Paulo Fernando;Demétrio, Clarice Garcia Borges;Ribeiro Júnior, Paulo Justiniano;Meyer, Paula Marques;Corassin, Carlos Humberto;Cassoli, Laerte Dagher;
Revista Brasileira de Zootecnia , 2004, DOI: 10.1590/S1516-35982004000300011
Abstract: the relationship between milk somatic cells count (scc) and milk yield has been the aim of countless researches in several countries; however, in brazil, the literature related to this subject is scarce. therefore, the objective of this study is to verify if the losses in milk yield due to scc increase are proportional to the yield, or absolute (independent of it) and starting from which scc, the losses become evident. for this study, 13.725 observations were used, collected monthly from 6 different herds, from january/2001 up to june/2002. the analysis model, for lactation curve, was based upon the incomplete gama function, considering the effects of lactation order, herd and calving season. the scc entered in that model in two ways: as multiplicative factor (representing relative losses) and as addictive factor (representing absolute losses). the best model was chosen based on the information criteria of schwarz (bic). it is concluded that the losses are absolute, becoming evident from 17.000 cells/ml, and they are 238 and 868 ml/day for each increase of one unit in the natural logarithm scale, starting from that scc, respectively, for primiparous and multiparous.
Bayesian analysis for a class of beta mixed models
Wagner Hugo Bonat,Paulo Justiniano Ribeiro Jr,Silvia emiko Shimakura
Statistics , 2014,
Abstract: Generalized linear mixed models (GLMM) encompass large class of statistical models, with a vast range of applications areas. GLMM extends the linear mixed models allowing for different types of response variable. Three most common data types are continuous, counts and binary and standard distributions for these types of response variables are Gaussian, Poisson and Binomial, respectively. Despite that flexibility, there are situations where the response variable is continuous, but bounded, such as rates, percentages, indexes and proportions. In such situations the usual GLMM's are not adequate because bounds are ignored and the beta distribution can be used. Likelihood and Bayesian inference for beta mixed models are not straightforward demanding a computational overhead. Recently, a new algorithm for Bayesian inference called INLA (Integrated Nested Laplace Approximation) was proposed.INLA allows computation of many Bayesian GLMMs in a reasonable amount time allowing extensive comparison among models. We explore Bayesian inference for beta mixed models by INLA. We discuss the choice of prior distributions, sensitivity analysis and model selection measures through a real data set. The results obtained from INLA are compared with those obtained by an MCMC algorithm and likelihood analysis. We analyze data from an study on a life quality index of industry workers collected according to a hierarchical sampling scheme. Results show that the INLA approach is suitable and faster to fit the proposed beta mixed models producing results similar to alternative algorithms and with easier handling of modeling alternatives. Sensitivity analysis, measures of goodness of fit and model choice are discussed.
Contagem de células somáticas e produ o de leite em vacas holandesas de alta produ o
Coldebella Arlei,Machado Paulo Fernando,Demétrio Clarice Garcia Borges,Ribeiro Júnior Paulo Justiniano
Pesquisa Agropecuária Brasileira , 2003,
Abstract: A mastite bovina pode ser clínica, com sinais visíveis, e subclínica, diagnosticada pela contagem das células somáticas. As perdas econ micas causadas pela mastite subclínica devem ser quantificadas para atender à demanda nacional de produtos lácteos. O objetivo deste trabalho foi verificar se as perdas na produ o de leite, pelo aumento do número de células somáticas, s o proporcionais ou independentes do nível de produ o. Foram utilizadas 7.756 observa es, colhidas mensalmente de um único rebanho, de setembro de 2000 a junho de 2002. A curva de lacta o foi modelada pela fun o gama incompleta, e os efeitos de ordem de lacta o, época do parto, ocorrência de doen as no periparto e escore de condi o corporal ao parto também foram considerados. A contagem de células somáticas foi incluída nesse modelo como fator multiplicativo, representando perdas relativas, e como fator aditivo, representando perdas absolutas. A escolha do melhor modelo foi baseada no critério de informa o de Schwarz (BIC). As perdas s o absolutas, evidentes a partir de 14.270 células/mL e para cada aumento de uma unidade na escala do logaritmo natural a partir desse valor, estimam-se perdas de 184 e 869 g/dia para vacas primíparas e multíparas, respectivamente.
Modelo autologístico espa?o-temporal com aplica??o à análise de padr?es espaciais da leprose-dos-citros
Franciscon, Luziane;Ribeiro Junior, Paulo Justiniano;Krainski, Elias Teixeira;Bassanezi, Renato Beozzo;Czermainski, Ana Beatriz Costa;
Pesquisa Agropecuária Brasileira , 2008, DOI: 10.1590/S0100-204X2008001200006
Abstract: the goal of this study was to propose modeling strategies applied to the analysis of citrus leprosis incidence, through the use of a spatial temporal autologistic model. we evaluated the adequacy of autologistic model to consider data collected at different times; to detect spatial-temporal patterns through different neighboring structures; to consider the effect of covariates from previous times; and assessing the effect of the presence of the disease vector in the probability of new infections occurrence. the spatial temporal autologistic model adopted has extended the usual logistic model, in which the neighboring structures is described by means of covariates built from the status of plants nearby, at the same or at previous times. data regarding the presence of the leprosis on plants were collected at field points referenced in space, over a period of approximately two years. models detect the presence of spatial patterns on new infections for the studied neighboring structures, at the same or previous time. additionally, probability estimates of a plant become infected can be obtained from the fitted models, given the occurrence of the disease and vector.
Compara??o das comunidades de Entomobryidae e Isotomidae (Collembola) entre plantio direto em três níveis de fertilidade, plantio convencional e um ecossistema natural (campo nativo) em Ponta Grossa, Paraná, Brasil
Sautter, Klaus Dieter;Santos, Honório Roberto dos;Ribeiro Júnior, Paulo Justiniano;
Revista Brasileira de Zoologia , 1999, DOI: 10.1590/S0101-81751999000100006
Abstract: this work had as objective to compare the communities of entomobryidae and isotomidae (collembola) among no-tillage in three fertility levels, conventional tillage and a natural ecosystem (native grassland). in the no-tillage in low fertility and medium fertility entomobryidae and isotomidae had populational picks in the winter and in the summer. in the no-tillage in area of high fertility, there was a populational pick for both families in the summer. in relation to the conventional tillage, entomobryidae had a populational pick in the winter, and isotomidae in the winter and in the summer. in the natural ecosystem entomobryidae presented populational picks in the winter and in the summer and isotomidae had regular populational fluctuation along the period of the experiment. the final mean density of entomobryidae was larger in the natural ecosystem, proceeded by the treatments of no-tillage and finally, for the conventional tillage. in relation to isotomidae, the no-tillage in area of low fertility was superior, coming the conventional tillage soon after, the no-tillage in médium and high fertility, and, finally, the natural ecosystem.
Compara??o das comunidades de Sminthuroidea e Onychiuridae (Collembola) entre plantio direto em três níveis de fertilidade, plantio convencional e um ecossistema natural (campo nativo) em Ponta Grossa, Paraná, Brasil
Sautter, Klaus Dieter;Santos, Honório Roberto dos;Ribeiro Júnior, Paulo Justiniano;
Revista Brasileira de Zoologia , 1999, DOI: 10.1590/S0101-81751999000100007
Abstract: this work had as objective to compare the communities of sminthuroidea and onychiuridae (collembola) among no-tillage in three fertility levels, conventional tillage and a natural ecosystem (native grassland). in the conventional tillage and in the no-tillage in area of medium fertility, the community of sminthuroidea had regular fluctuation along the period of the experiment, but wtth low densities. the no-tillage in area of high fertility presented a populational pick in the autumn; the no-tillage in area of low fertility, in the spring; and, the natural ecosystem, in the summer. as the final mean density of the population of sminthuroidea, was observed that the no-tillage in area of low fertility went numerically superior to the others, proceeded by the natural ecosystem, no-tillage in area of high fertility, conventional tillage, and, finally, no-tillage in area of medium fertility. onychiuridae had three populational picks in the no-tillage in area of low fertility: being a larger in the winter and other two, smaller in the summer and in the autumn. in the no-tillage in area of medium fertility presented only a populational pick in the winter. in the other treatments there was not significantly populational picks. in relation to the final mean density ofthe community of onychiuridae, the no-tillage plantation in area of low fertility was superior, proceeded by the other treatments of no-tillage, and, in third plan, the natural ecosystem and the conventional tillage.
Autologistic model with an application to the citrus "sudden death" disease
Krainski, Elias Teixeira;Ribeiro Junior, Paulo Justiniano;Bassanezi, Renato Beozzo;Franciscon, Luziane;
Scientia Agricola , 2008, DOI: 10.1590/S0103-90162008000500014
Abstract: the citrus sudden death (csd) disease affects dramatically citrus trees causing a progressive plant decline and death. the disease has been identified in the late 90's in the main citrus production area of brazil and since then there are efforts to understand the etiology as well as the mechanisms its spreading. one relevant aspect of such studies is to investigate spatial patterns of the occurrence within a field. methods for determining whether the spatial pattern is aggregated or not has been frequently used. however it is possible to further explore and describe the data by means of adopting an explicit model to discriminate and quantify effects by attaching parameters to covariates which represent aspects of interest to be investigated. one alternative involves autologistic models, which extend a usual logistic model in order to accommodate spatial effects. in order to implement such model it is necessary to take into account the reuse of data to built spatial covariates, which requires extensions in methodology and algorithms to assess the variance of the estimates. this work presents an application of the autologistic model to data collected at 11 time points from citrus fields affected by csd. it is shown how the autologistic model is suitable to investigate diseases of this type, as well as a description of the model and the computational aspects necessary for model fitting.
Influência do boro, de fontes de nitrogênio e do pH do solo no controle de hérnia das crucíferas causada por Plasmodiophora brassicae
Ruaro, Lucimeris;Lima Neto, Vismar da C.;Ribeiro Júnior, Paulo Justiniano;
Tropical Plant Pathology , 2009, DOI: 10.1590/S1982-56762009000400005
Abstract: effects of boron (b) doses and nitrogen sources (n) at different levels of soil ph on the control of clubrootwas investigated in transplants of chinese cabbage grown in pots containing field soil.. b dissolved in water was applied at 0, 5, 10, 20 and 30 mg.kg-1 of soil of ph 5.5, 6.2 and 7.3 on the day before transplanting. n sources tested (ammonium sulfate, urea and calcium nitrate) were applied to soil of ph 5.5 and 7.3. seedlings were inoculated with a suspension of resting spores of the pathogen at transplanting and assessed for clubroot severity after 45 days. the disease was severe (70%) when the b dose was less than 10 mg.kg-1 and the ph less than 6.0, but milder (26%) when the b dose was 10 to 30 mg.kg-1 soil at ph values higher than 6.5. clubroot was least severe when calcium nitrate was used in soil of ph 6.5. clubroot severity correlated negatively with concentrations of n, ca, mg and b in the foliage. we conclude that use of 10 to 30 mg.kg-1 boron and calcium nitrate in soil of ph 6,5 or 7,3 was effective in reducing club root severity.
Aplica??o de métodos geoestatísticos para identifica??o de dependência espacial na análise de dados de um ensaio de espa?amento florestal em delineamento sistemático tipo leque
Oda-Souza, Melissa;Barbin, Décio;Ribeiro Júnior, Paulo Justiniano;Stape, José Luiz;
Revista árvore , 2008, DOI: 10.1590/S0100-67622008000300011
Abstract: the systematic design stands out for its compactness, broadness and for allowing the testing of a larger number of spacings. however, it is not used due to the systematic arrangement (non-randomized) of the plants and the high sensibility for missing values. the aim of this work was to describe the geostatistic model and associated methods of inference in the analysis context of non-randomized experiment, reporting applied results to identify the spatial dependence in a fan systematic design of eucalyptus dunnii. furthermore, different alternatives for treating missing values that can occur from flaws and/or mortality of plants were proposed, analyzed and compared. data were analyzed by three models that differed, with covariates, in the form of modeling missing data values. a semivariogram was built for each model, adjusting three correlation function models, being the parameters estimated through the maximum likelihood method and selected by the akaike's criterion. these models, with and without the spatial component, were compared by the likelihood ratio test. the results showed that: (1) the covariates interacted positively with the response variable, avoiding data to be discarded; (2) the model comparison, with and without the spatial component, did not confirm the existence of dependence; (3) the incorporation of the spatial dependence structure into the observational models recovered the capacity to make valid inferences in the absence of randomization, overcoming operational problems and guaranteeing that the data can be subjected to classic analysis.
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