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Search Results: 1 - 10 of 17957 matches for " Demétrio Clarice Garcia Borges "
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Growth Curves for Diameter and Height Using Mixed Models: An Application in Eucalyptus Seedling  [PDF]
Giovana Fumes, Clarice Garcia Borges Demétrio, Cristian Villegas, José Eduardo Corrente, Juliane Fumes Bazzo
Open Journal of Forestry (OJF) , 2017, DOI: 10.4236/ojf.2017.74024
Abstract: The growth of a tree or a forest settlement is of great value to a forest enterprise, because many decisions are directly dependent of this information, for instance, determining the optimal cutting age. This study aims to apply a new class of models to fit growth curves for diameter and height of Eucalyptus grandis X Eucalyptus urophylla seedling data. Data were collected from a trial conducted in a green house at the Natural Resources Department at School of Agriculture, Botucatu, S?o Paulo, Brazil. The experiment’s design was completely randomized with eight treatments and four replications. In this trial, the growth variables referring to the height and the diameter were evaluated, being measured five and four times, respectively. The methodology was carried in a mixed longitudinal model using a new approach based on Box-Cox Normal (BCN) distribution, and comparisons with this model were made assuming normality of the data. The results revealed that the BCN mixed model provided similar results to the standard model in order to estimate growth curves; however, the BCN model was the best result according to Akaike criterion, considering the slight asymmetry in the data set. This approach is of great interest in case of outliers and robust procedures for parameter estimation.
Modifications for the tukey test procedure and evaluation of the power and efficiency of multiple comparison procedures
Conagin, Armando;Barbin, Décio;Demétrio, Clarice Garcia Borges;
Scientia Agricola , 2008, DOI: 10.1590/S0103-90162008000400016
Abstract: multiple pairwise comparison tests of treatment means are of great interest in applied research. two modifications for the tukey test were proposed. the power of unilateral and bilateral student, waller-duncan, duncan, snk, regwf, regwq, tukey, bonferroni, sidak, unilateral dunnet statistical tests and the modified tests, sidak, bonferroni 1 and 2, tukey 1 and 2, has been compared using the monte carlo method. data were generated for 600 experiments with eight treatments in a randomized block design, of which 400 had four and 200 eight blocks. the differences between the treatment means in relation to the control were 30%, 20%, 15%, 10%, 5%. two extra treatments did not differ from the control. a coefficient of variation of 10% and a probability type i error of α = 0.05 were adopted. the power of all the tests decreased when the differences to the control, decreased. the unilateral and bilateral student t, waller-duncan and duncan tests showed greater number of significative differences, followed by unilateral dunnett, modified sidak, modified bonferroni 1 and 2, modified tukey 1, snk, regwf, regwq, modified tukey 2, tukey, sidak and bonferroni. there is great loss of efficiency for all tests in relation to the unilateral student t test for each difference of the treatment to the control, when the differences between means decrease. the modified tests were always more efficient than their original ones.
Mixed-effects growth curves in the valuation of Nellore sires
Giolo, Suely Ruiz;Henderson, Robin;Demétrio, Clarice Garcia Borges;
Scientia Agricola , 2009, DOI: 10.1590/S0103-90162009000100012
Abstract: cattle breeding programmes need objective criteria in order to evaluate and subsequently improve production systems. this work uses a logistic growth curve model for evaluating sires based on their progeny weight measured repeatedly over time. the parameters of the curve are described as a linear function of fixed and random effects. a bayesian approach is used for the estimation. analysis of the weights recorded on animals of the nellore breed shows that growth curve models with fixed and random effects can be useful to evaluate and selecting sires.
Spatio-temporal modelling of coffee berry borer infestation patterns accounting for inflation of zeroes and missing values
Ruiz-Cárdenas, Ramiro;Assun??o, Renato Martins;Demétrio, Clarice Garcia Borges;
Scientia Agricola , 2009, DOI: 10.1590/S0103-90162009000100014
Abstract: the study of pest distributions in space and time in agricultural systems provides important information for the optimization of integrated pest management programs and for the planning of experiments. two statistical problems commonly associated to the space-time modelling of data that hinder its implementation are the excess of zero counts and the presence of missing values due to the adopted sampling scheme. these problems are considered in the present article. data of coffee berry borer infestation collected under colombian field conditions are used to study the spatio-temporal evolution of the pest infestation. the dispersion of the pest starting from initial focuses of infestation was modelled considering linear and quadratic infestation growth trends as well as different combinations of random effects representing both spatially and not spatially structured variability. the analysis was accomplished under a hierarchical bayesian approach. the missing values were dealt with by means of multiple imputation. additionally, a mixture model was proposed to take into account the excess of zeroes in the beginning of the infestation. in general, quadratic models had a better fit than linear models. the use of spatially structured parameters also allowed a clearer identification of the temporal increase or decrease of infestation patterns. however, neither of the space-time models based on standard distributions was able to properly describe the excess of zero counts in the beginning of the infestation. this overdispersed pattern was correctly modelled by the mixture space-time models, which had a better performance than their counterpart without a mixture component.
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.
Spatial pattern detection modeling of thrips (Thrips tabaci) on onion fields
Ribeiro Jr, Paulo Justiniano;Viola, Denise Nunes;Demétrio, Clarice Garcia Borges;Manly, Bryan F.;Fernandes, Odair Aparecido;
Scientia Agricola , 2009, DOI: 10.1590/S0103-90162009000100013
Abstract: onion (allium cepa) is one of the most cultivated and consumed vegetables in brazil and its importance is due to the large laborforce involved. one of the main pests that affect this crop is the onion thrips (thrips tabaci), but the spatial distribution of this insect, although important, has not been considered in crop management recommendations, experimental planning or sampling procedures. our purpose here is to consider statistical tools to detect and model spatial patterns of the occurrence of the onion thrips. in order to characterize the spatial distribution pattern of the onion thrips a survey was carried out to record the number of insects in each development phase on onion plant leaves, on different dates and sample locations, in four rural properties with neighboring farms under different infestation levels and planting methods. the mantel randomization test proved to be a useful tool to test for spatial correlation which, when detected, was described by a mixed spatial poisson model with a geostatistical random component and parameters allowing for a characterization of the spatial pattern, as well as the production of prediction maps of susceptibility to levels of infestation throughout the area.
Statistical models in agriculture: biometrical methods for evaluating phenotypic stability in plant breeding
Daniel Furtado Ferreira,Clarice Garcia Borges Demétrio,Bryan Frederick John Manly ,Roland Vencovsky,Amauri de Almeida Machado
CERNE , 2006,
Abstract: This paper reviews the main concepts of several methods of phenotypic stability analysis and points out their advantages and limitations. It was concluded that the simple linear regression method of Eberhart & Russel (1966) and the bi?segmented regression method of Silva & Barreto (1985) have only historical importance nowadays. Moreover, based on factors discussed in the paper, it is recommended that the regression models of Toler & Burrows (1998) and the Additive Main effects and Multiplicative Interactions (AMMI) model should be used simultaneously to study and to estimate phenotypic stability effects.
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.
Host colonization differences between citrus and coffee isolates of Xylella fastidiosa in reciprocal inoculation
Prado, Simone de Souza;Lopes, Jo?o Roberto Spotti;Demétrio, Clarice Garcia Borges;Borgatto, Adriano Ferreti;Almeida, Rodrigo Piacentini Paes de;
Scientia Agricola , 2008, DOI: 10.1590/S0103-90162008000300005
Abstract: citrus variegated chlorosis (cvc) and coffee stem atrophy (csa) are important diseases in brazil associated with closely-related strains of xylella fastidiosa, but little is know about host aoverlappingnd importance of citrus and coffee as inoculum sources of these strains. in this study, reciprocal-inoculation experiments were performed to determine if cvc and csa isolates are biologically similar within citrus and coffee plants. these two hosts were mechanically inoculated with a cvc and a csa isolate of x. fastidiosa at four concentrations ranging between103 and 109 colony forming units cfu ml-1. at two, four and eight months after inoculation, the infection efficiency and bacterial populations of the isolates in each host were determined by culturing. the cvc isolate infected both citrus and coffee plants, but developed lower populations in coffee. the csa isolate did not colonize citrus. inoculation of coffee plants with the cvc isolate resulted in low rates of infection and required an inoculum concentration ten-fold higher than that necessary to obtain a similar (25%) rate of infection in citrus. the relatively low infection rates and bacterial numbers of the cvc isolate in coffee plants compared with those observed in citrus suggest that coffee is not a suitable host to serve as a source of inoculum of the cvc strain for primary spread to citrus or within coffee plantations.
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