Paulo Justiniano Ribeiro Jr

Universidade Federal do Paraná | UFPR · Department of Statistics

Clustered competing risks data are a complex failure time data scheme. Its main characteristics are the cluster structure, which implies a latent within-cluster dependence between its elements, and its multiple variables competing to be the one responsible for the occurrence of an event, the failure. To handle this kind of data, we propose a full l...

Researchers are often interested in understanding the relationship between a set of covariates and a set of response variables. To achieve this goal, the use of regression analysis, either linear or generalized linear models, is largely applied. However, such models only allow users to model one response variable at a time. Moreover, it is not poss...

Univariate regression models have rich literature for counting data. However, this is not the case for multivariate count data. Therefore, we present the Multivariate Generalized Linear Mixed Models framework that deals with a multivariate set of responses, measuring the correlation between them through random effects that follows a multivariate no...

We propose a covariance specification for modeling spatially continuous multivariate data. This model is based on a reformulation of Kronecker’s product of covariance matrices for Gaussian random fields. The structure holds for different choices of covariance functions with parameters varying in their usual domains. In comparison with classical mod...

Researchers are often interested in understanding the relationship between a set of covariates and a set of response variables. To achieve this goal, the use of regression analysis, either linear or generalized linear models, is largely applied. However, such models only allow users to model one response variable at a time. Moreover, it is not poss...

Distribution selection plays a key role in parametric statistics. Choosing one from a set of candidate distributions that best fits the sample data is a recurring task in a large number of statistical analysis. The choice of a misspecified and/or poor fitted distribution can lead to unreliable results and conclusions. Although distribution selectio...

We propose a covariance specification for modeling spatially continuous multivariate data. This model is based on a reformulation of Kronecker’s product of covariance matrices for Gaussian random fields. We illustrate the case with the Matérn function used for specifying marginal covariances. The structure holds for other choices of covariance func...

Noise pollution affects quality of life, well-being, and is a public health problem. In educational environments, high noise levels affect the concentration and performance of students. The Polytechnic Center Campus of UFPR is affected by several sound sources and frequented by a large number of users, which points to the need for noise management....

Researchers are often interested in understand the relationship between a set of covari- ates and a set of response variables. In order to achieve this goal, the use of regression analysis, either linear or generalized linear models, is largely applied. However, such models only allow users to model one response variable at a time. Moreover, it is...

In the analysis of multivariate spatial random elds, it is essential to dene a covariance structure that adequately models the relationship between the variables under study. We propose a covariance structure with exponential correlation function for bivariate random elds, the SEC model. We compare the SEC model fits with the bivariate separable ex...

We investigated a Gaussian conditional geostatistical spatio-temporal model (CGSTM) aiming to fit data observed at non-fixed locations over discrete times, based only on the observed locations. The model specifies the process state at the current time conditioning on the process state in the recent past. Particularly, the process mean uses a weight...

In commercial sheries, catches of species that are not the main target, are called "bycatch". In the Atlantic Ocean, the Black Marlin (Makaira nigricans) is caught incidentally by vessels using longline as shing gear, and targeting tunas and swordsh. Analysis of temporal patterns in a historical context can help in decisions for sheries management....

For some ranges of its parameters and arguments, the series for Tweedie probability density functions are sometimes exceedingly difficult to sum numerically. Existing numerical implementations utilizing inversion techniques and properties of stable distributions can cope with these problems, but no single one is successful in all cases. In this wor...

Many methods used in spatial statistics are computationally demanding, and so, the development of more computationally efficient methods has received attention. A important development is the integrated nested Laplace approximation method which is carry out Bayesian analysis more efficiently This method, for geostatistical data, is done considering...

Leprosis is caused by the Citrus leprosis virus cytoplasmic type and is vectored by the mite Brevipalpus yothersi. Miticide applications, which cost US $54 million annually, are based on inspecting for the presence of mites. The aim of the present study was to characterise the spatial patterns of B. yothersi‐infested trees and leprosis symptomatic...

Spatial variability depends on the sampling configuration and characteristics associated with the georeferenced phenomenon, such as geometric anisotropy. This study aimed to determine the influence of the sampling design on parameter estimation in an anisotropic geostatistical model and the spatial estimation of a georeferenced variable at unsample...

Integrated crop-livestock systems (ICLS) are sustainable options for agricultural diversification, but there have been few studies on the influence of ICLS on soil microorganisms. This work investigated the influence of agropastoral (AP) and agrosilvopastoral (ASP) systems, compared with a non-integrated crop (CO) on the suppression of Rhizoctonia...

Studying and understanding the behaviour of certain kinds of insects and/or pests in a plantation is critical in any region, since it gives subsidies for possible public and/or private policies if any intervention is needed. In this context, many different studies are available in a wide literature, e.g. about spatial patterns of termite mounds, th...

O presente estudo teve como objetivo utilizar o compartilhamento de parâmetros de modelos geoestatísticos aplicado aos estimadores de máxima verossimilhança para predizer os volumes por hectare em três fragmentos de Floresta Estacional Subtropical localizados em Santa Teresa - RS empregando a abordagem Borrow strenght. Os dados foram coletados em 5...

While integrated crop-livestock systems including trees have received more attention during the last two decades, the epidemiology of plant diseases in these production systems is still poorly understood. Microclimatic modifications due to the type of cropping system adopted may affect the epidemic patterns. This work aimed to evaluate whether powd...

This study aimed to use the share parameters of the geo-statistical models applied to maximum likelihood estimators to predict the volumes per hectare in three fragments of a Deciduous Forest located in Santa Teresa, RS state, employing the ‘Borrow Strength’ approach. Data were collected in 56 sampling units (S.U) of variable sizes with approximate...

We propose a model-based geostatistical approach to deal with regionalized compositions. We combine the additive-log-ratio transformation with multivariate geostatistical models whose covariance matrix is adapted to take into account the correlation induced by the compositional structure. Such specification allows the usage of standard likelihood m...

Neste trabalho, teve-se o objetivo de estudar e comparar mapas temáticos da produtividade da soja para diferentes grades amostrais, utilizando métodos geoestatísticos (função semivariância e krigagem). A análise foi realizada com dados da produtividade de soja em t ha-1 numa área comercial com grades regulares e distâncias entre pontos de 25x25 m,...

This study aimed to compare thematic maps of soybean yield for different sampling grids, using geostatistical methods (semivariance function and kriging). The analysis was performed with soybean yield data in t ha(-1) in a commercial area with regular grids with distances between points of 25x25 m, 50x50 m, 75x75 m, 100x100 m, with 549, 188, 66 and...

This study characterizes the spatial dynamics of Plum Leaf Scald on three commercial orchards located in Sao Paulo State-Brazil. All trees from each orchard were evaluated during four consecutive years (one orchard),and for three consecutive years (two orchards). The incidence and characteristics of spatial patterns were assessed by the binomial di...

Combined log-likelihood for comparison of spatial continuity structures in deciduous forest. The present study aimed to examine spatial dependence and distribution of volume in three fragments of Subtropical forest, geographically separated and the different post-intervention ages, using a single geostatistical model or combined model. Data were co...

We investigate an algorithm for maximum likelihood estimation of spatial generalized linear mixed models based on the Laplace approximation. We compare our algorithm with a set of alternative approaches for two datasets from the literature. The Rhizoctonia root rot and the Rongelap are, respectively, examples of binomial and count datasets modeled...

ESTIMAÇÃO DE CONTRASTES DE MÉDIAS DE TRATAMENTOS EM UM EXPERIMENTO EM BLOCOS AO ACASO, UTILIZANDO AS ANÁLISES CLÁSSICA E ESPACIAL

A análise de sobrevivência é aplicada quando o tempo até a ocorrência de um evento for o objeto de interesse. Em doenças de plantas, dados dessa natureza são rotineiramente coletados, embora aplicações do método sejam pouco comuns. O objetivo deste trabalho foi utilizar dois estudos de doenças em pós-colheita de pêssegos, considerando-se safras con...

We give an overview of the papers published in this special issue on spatial statistics, of the Journal of Statistical Software. 21 papers address issues covering visualization (micromaps, links to Google Maps or Google Earth), point pattern analysis, geostatistics, analysis of areal aggregated or lattice data, spatio-temporal statistics, Bayesian...

Most of the mathematical models developed for rare events are based on probabilistic models for extremes. Although the tools for statistical modeling of univariate and multivariate extremes are well developed, the extension of these tools to model spatial extremes includes an area of very active research nowadays. A natural approach to such a model...

In this work, kriging with covariates is used to model and map the spatial distribution of salinity measurements gathered by an autonomous underwater vehicle in a sea outfall monitoring campaign aiming to distinguish the effluent plume from the receiving waters and characterize its spatial variability in the vicinity of the discharge. Four differen...

Peach rust (Tranzschelia discolor) is a major foliar disease of peach that can cause severe defoliation. Few epidemiological studies have been conducted on peach rust, and there is no information concerning the spatial distribution of the disease within the canopy. This study aimed to characterise the onset and temporal progress of peach rust in th...

Citrus postbloom fruit drop (PFD) is caused by Colletotrichum acutatum and C. gloeosporioides. These pathogens attack the flowers and cause premature fruit drop and the retention of fruit calyces. This study was designed to characterize the spatial and temporal dynamics of PFD in commercial citrus-growing areas to better understand the disease spre...

The spatial variability of structures in regionalized variables are defined with the aid of geostatistical techniques, which facilitate the estimation of values for these variables in unsampled localizations and generate thematic maps to be used in decision making for localized treatments in the area under study. The quality of these maps depends o...

Generalized linear mixed models (GLMM) are a large class of statistical models, with applications in many areas of science. GLMM extends the linear mixed models allowing different types of response variable. There are three main data types : continuous, counts and binary. Common distributions for these types of response variables are Gaussian, Pois...

Este estudo analisa o Exame Nacional de Desempenho do Estudante (Enade) na área de Estatística em 2009, provas objetivas, pela Teoria de Resposta ao Item (TRI). O Enade não aplica a TRI, mas a perspectiva dessa abordagem é de fornece uma visão geral da utilização através dos modelos de teoria de resposta ao item unidimensional e multidimensional. C...

Event counts are response variables with non-negative integer values representing the number of times that an event occurs within a fixed domain such as a time interval, a geographical area or a cell of a contingency table. Analysis of counts by Gaussian regression models ignores the discreteness, asymmetry and heterocedasticity and is inefficient,...

Beta regression models are a suitable choice for continuous response variables on the unity interval. Random effects add further flexibility to the models and accommodate data structures such as hierarchical, repeated measures and longitudinal, which typically induce extra variability and/or dependence. Closed expressions cannot be obtained for par...

The study on spatial variability of soil properties performed through geostatistical techniques allow us to identify the spatial distribution of phenomena by means of a spatial model that considers degree of dependence among observed data, depending on distance and also the direction that separate them, if there is geometric anisotropy, in other wo...

Aedes aegypti has developed evolution-driven adaptations for surviving in the domestic human habitat. Several trap models have been designed considering these strategies and tested for monitoring this efficient vector of Dengue. Here, we report a real-scale evaluation of a system for monitoring and controlling mosquito populations based on egg samp...

Survival analysis is applied when the time until the occurrence of an event is the object of interest. Such data are routinely collected in plant pathology whereas application of methods of survival analysis is uncommon. Basic concepts in survival analysis for use in plant pathology such as Kaplan-Meier methods, log-rank test and Cox proportional h...

Na modelagem estatística da variabilidade espacial, estimam-se os parâmetros da dependência espacial, que são utilizados na interpolação de valores em locais não amostrados. Para tal, o processo de modelagem deve ser realizado com critérios estatísticos que garantam predições confiáveis e representem a real variabilidade local. Este trabalho avalio...

O dengue é um problema de saúde pública em todas as regiões brasileiras. Como não se dispõe de uma vacina efetiva, o elo vulnerável da cadeia epidemiológica é o vetor, o mosquito Aedes aegypti. O entendimento das flutuações na população do mosquito é instrumental para reduzir a sua proliferação e a exposição das pessoas à infecção. Uma classe de...

RESUMO Na modelagem estatística da variabilidade espacial, estimam-se os parâmetros da dependência espacial, que são utilizados na interpolação de valores em locais não amostrados. Para tal, o processo de modelagem deve ser realizado com critérios estatísticos que garantam predições confiáveis e representem a real variabilidade local. Este trabalho...

As a consequence of the current globalization of commerce, natural environments are subject to an unprecedented dynamic transport of organisms because global conditions favor transport, settlement, and dispersal of invading species. These produce widespread impacts such as decreased agricultural and utility production, increased health risks to hum...

This study aimed to evaluate the spatial variability of leaf content of macro and micronutrients. The citrus plants orchard with 5 years of age, planted at regular intervals of 8 x 7 m, was managed under drip irrigation. Leaf samples were collected from each plant to be analyzed in the laboratory. Data were analyzed using the software R, version 2....

This study demonstrates that the use of information from medical prescriptions is essential for understanding the dynamics of community bacterial resistance. The resulting analysis can also influence and help establish more adequate public health policies on the control and optimization of antimicrobial use. The article demonstrates the use of a lo...

Regression models are widely used on a diversity of application areas to describe associations between explanatory and response variables. The initially and frequently adopted Gaussian linear model was gradually extended to accommodate different kinds of response variables. These models were latter described as particular cases of the generalized l...

O s desempenhos dos modelos geoestatistico e aditivo generalizado com thin plate splines para a reconstituicao de superficies continuas gaussianas sao comparados atraves de um estudo de simulacao. O procedimento proposto para a comparacao leva em consideracao fatores sobre o processo gerador da superficie, variabilidade e suavidade, bem como, para...

Resumo: A captura de espécies exploradas em pescarias comerciais normalmenté e modelada sem qualquer consideração sobre a dependência do espaço e do tempo. Os modelos espaço-temporais representam uma maneira mais acurada para a modelagem de dados de populações biológicas, onde existe dependência no espaço, no tempo, e possivelmente na interação esp...

Population antimicrobial use may influence resistance emergence. Resistance is an ecological phenomenon due to potential transmissibility. We investigated spatial and temporal patterns of ciprofloxacin (CIP) population consumption related to E. coli resistance emergence and dissemination in a major Brazilian city. A total of 4,372 urinary tract inf...

O tamanho e forma da unidade amostral tem grande influência na percepção da autocorrelação espacial. Dessa forma, a escolha de uma escala adequada para o estudo de processos espaciais é extremamente importante, pois a dinâmica espacial pode ser considerada significante, insignificante ou inoperante a depender da escala utilizada ou, ainda, as relaç...

Resumo A teoria clássica de amostragem aplicada a estudos ecológicos geralmente tem o objetivo de realizar inferência sobre os parâmetros de comunidades e populações. No entanto, muitas vezes o interesse é também o reconhecimento do padrão espacial das comunidades. Neste trabalho foram ajustados modelos que permitem comparar as estruturas espaciai...

Aedes aegypti is a very efficient disseminator of human pathogens. This condition is the result of evolutionary adaptations to frequent haematophagy, as well as to the colonization of countless types of habitats associated with environmental and cultural factors that favor the proliferation of this mosquito in urban ecosystems. Studies using sensit...

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 (ammoni...