scholarly journals Inferring signalling networks from longitudinal data using sampling based approaches in the R-package 'ddepn'

2011 ◽  
Vol 12 (1) ◽  
Author(s):  
Christian Bender ◽  
Silvia vd Heyde ◽  
Frauke Henjes ◽  
Stefan Wiemann ◽  
Ulrike Korf ◽  
...  
Keyword(s):  
PLoS ONE ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. e0230276 ◽  
Author(s):  
Milan Wiedemann ◽  
Graham R. Thew ◽  
Richard Stott ◽  
Anke Ehlers

2021 ◽  
Author(s):  
Leonie V. D. E. Vogelsmeier ◽  
Jeroen K. Vermunt ◽  
Kim De Roover

Intensive longitudinal data (ILD) have become popular for studying within-person dynamics in psychological constructs (or between-person differences therein). Prior to investigating what the dynamics look like, it is important to examine whether the measurement model (MM) is the same across subjects and time and, thus, whether the measured constructs have the same meaning. If the MM differs (e.g., because of changes in item interpretation or response styles), observations cannot be validly compared. Exploring differences in the MM for ILD can be done with latent Markov factor analysis (LMFA), which classifies observations based on the underlying MM (for many subjects and time-points simultaneously) and thus shows which observations are comparable. However, the complexity of the method or the fact that no open-source software for LMFA existed until now may have hindered researchers from applying the method in practice. In this article, we introduce the new user-friendly software package lmfa, which allows researchers to perform the analysis in the freely available software R. We provide a step-by-step tutorial for the lmfa package so that researchers can easily investigate MM differences in their own ILD.


2020 ◽  
Vol 93 (2) ◽  
Author(s):  
Cong Xu ◽  
Pantelis Z. Hadjipantelis ◽  
Jane-Ling Wang

2020 ◽  
Vol 29 (9) ◽  
pp. 2697-2716
Author(s):  
Hélène Jacqmin-Gadda ◽  
Anaïs Rouanet ◽  
Robert D Mba ◽  
Viviane Philipps ◽  
Jean-François Dartigues

Quantile regressions are increasingly used to provide population norms for quantitative variables. Indeed, they do not require any Gaussian assumption for the response and allow to characterize its entire distribution through different quantiles. Quantile regressions are especially useful to provide norms of cognitive scores in the elderly that may help general practitioners to identify subjects with unexpectedly low cognitive level in routine examinations. These norms may be estimated from cohorts of elderly using quantile regression for longitudinal data, but this requires to properly account for selection by death, dropout and intermittent missing data. In this work, we extend the weighted estimating equation approach to estimate conditional quantiles in the population currently alive from mortal cohorts with dropout and intermittent missing data. Suitable weight estimation procedures are provided for both monotone and intermittent missing data and under two missing-at-random assumptions, when the observation probability given that the subject is alive depends on the survival time (p-MAR assumption) or not (u-MAR assumption). Inference is performed through subject-level bootstrap. The method is validated in a simulation study and applied to the French cohort Paquid to estimate quantiles of a cognitive test in the elderly population currently alive. On one hand, the simulations show that the u-MAR analysis is quite robust when the true missingness mechanism is p-MAR. This is a useful result because computation of suitable weights for intermittent missing data under the p-MAR assumption is untractable. On the other hand, the simulations highlight, along with the real data analysis, the usefulness of suitable weights for intermittent missing data. This method is implemented in the R package weightQuant.


2015 ◽  
Author(s):  
Benjamin Fanson ◽  
Kerry V Fanson

The growing number of wildlife endocrinology studies have greatly enhanced our understanding of comparative endocrinology, and have also generated extensive longitudinal data for a vast number of species. However, the extensive graphical analysis required for these longitudinal datasets can be time consuming because there is often a need to create tens, if not hundreds, of graphs. Furthermore, routine methods for summarising hormone profiles, such as the iterative baseline approach and area under the curve (AUC), can be tedious and non-reproducible, especially for large number of individuals. We developed an R package, hormLong, which provides the basic functions to perform graphical and numerical analyses routinely used by wildlife endocrinologists. To encourage its use, hormLong has been developed such that no familiarity with R is necessary. Here, we provide a brief overview of the functions currently available and demonstrate their utility with previously published Asian elephant data. We hope that this package will promote reproducibility and encourage standardization of wildlife hormone data analysis.


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