15 documents found, page 1 of 2
survidm: An R package for Inference and Prediction in an Illness-Death Model
Soutinho, Gustavo; Sestelo, Marta; Machado, Luís MeiraMulti-state models are a useful way of describing a process in which an individual moves through a number of finite states in continuous time. The illness-death model plays a central role in the theory and practice of these models, describing the dynamics of healthy subjects who may move to an intermediate "diseased" state before entering into a terminal absorbing state. In these models, one important goal is t...
clustcurv: An R Package for Determining Groups in Multiple Curves
Villanueva, Nora,M.; Sestelo, Marta; Machado, Luís Meira; Roca-Pardiñas, JavierIn many situations, it could be interesting to ascertain whether groups of curves can be performed, especially when confronted with a considerable number of curves. This paper introduces an R package, known as clustcurv, for determining clusters of curves with an automatic selection of their number. The package can be used for determining groups in multiple survival curves as well as for multiple regression cur...
A method for determining groups in multiple survival curves
Villanueva, Nora; Sestelo, Marta; Machado, Luís MeiraSurvival analysis includes a wide variety of methods for analyzing time‐to‐event data. One basic but important goal in survival analysis is the comparison of survival curves between groups. Several nonparametric methods have been proposed in the literature to test for the equality of survival curves for censored data. When the null hypothesis of equality of curves is rejected, leading to the clear conclusion th...
Estimation in the progressive illness-death model: a nonexhaustive review
Machado, Luís Meira; Sestelo, MartaMultistate models can be successfully used for describing complex event history data, for example, describing stages in the disease progression of a patient. The so‐called “illness‐death” model plays a central role in the theory and practice of these models. Many time‐to‐event datasets from medical studies with multiple end points can be reduced to this generic structure. In these models one important goal is t...
An R package for determining groups in multiple survival curves
Villanueva, Nora; Sestelo, Marta; Machado, Luís MeiraSurvival analysis includes a wide variety of methods for analyzing time-to-event data. One basic but important goal in survival analysis is the comparison of survival curves between groups. Several nonparametric methods have been proposed in the literature to test for the equality of survival curves for censored data. When the null hypothesis of equality of curves is rejected, leading to the clear conclusion th...
An R package for inference and prediction in an illness-death model
Machado, Luís Meira; Sestelo, MartaMulti-state models are a useful way of describing a process in which an individual moves through a number of nite states in continuous time. The illness-death model plays a central role in the theory and practice of these models, describing the dynamics of healthy subjects who may move to an intermediate `diseased' state before entering into a terminal absorbing state. In these models one important goal is the ...
npregfast: an R package for nonparametric estimation and inference in life scie...
Sestelo, Marta; Villanueva, Nora M.; Machado, Luís Meira; Roca-Pardiñas, JavierWe present the R npregfast package via some applications involved with the study of living organisms. The package implements nonparametric estimation procedures in regression models with or without factor-by-curve interactions. The main feature of the package is its ability to perform inference regarding these models. Namely, the implementation of different procedures to test features of the estimated regressio...
Nonparametric estimation of the survival function for ordered multivariate fail...
Machado, Luís Meira; Sestelo, Marta; Gonçalves, AndreiaIn longitudinal studies of disease, patients may experience several events through a follow-up period. In these studies, the sequentially ordered events are often of interest and lead to problems that have received much attention recently. Issues of interest include the estimation of bivariate survival, marginal distributions and the conditional distribution of gap times. In this work we consider the estimation...
condSURV: An R package for the estimation of the conditional survival function ...
Machado, Luís Meira; Sestelo, MartaOne major goal in clinical applications of time-to-event data is the estimation of survival with censored data. The usual nonparametric estimator of the survival function is the time-honored Kaplan-Meier product-limit estimator. Though this estimator has been implemented in several R packages, the development of the condSURV R package has been motivated by recent contributions that allow the estimation of the s...
Spawning habitat selection by the common cuttlefish Sepia officinalis in the Cí...
Guerra, Ángel; Hernández-Urcera, Jorge; Garci, Manuel E.; Sestelo, Marta; Regueira, Marcos; Gilcoto, Miguel; González, Ángel F.We evaluated specific habitat features (bottom substrate type, depth, temperature, season and latitude- longitude) at random locations in the Cíes Islands (Galician Atlantic Islands National Park, Northwest Spain) to determine their impact on Sepia officinalis spawning habitat use. We performed underwater visual transects via scuba diving. In total, 94 transects were conducted between April 30, 2012 and July 17...