Fitting Linear Mixed-Effects Models Using lme4
TLDR
In this article, a model is described in an lmer call by a formula, in this case including both fixed-and random-effects terms, and the formula and data together determine a numerical representation of the model from which the profiled deviance or the profeatured REML criterion can be evaluated as a function of some of model parameters.Abstract:
Maximum likelihood or restricted maximum likelihood (REML) estimates of the parameters in linear mixed-effects models can be determined using the lmer function in the lme4 package for R. As for most model-fitting functions in R, the model is described in an lmer call by a formula, in this case including both fixed- and random-effects terms. The formula and data together determine a numerical representation of the model from which the profiled deviance or the profiled REML criterion can be evaluated as a function of some of the model parameters. The appropriate criterion is optimized, using one of the constrained optimization functions in R, to provide the parameter estimates. We describe the structure of the model, the steps in evaluating the profiled deviance or REML criterion, and the structure of classes or types that represents such a model. Sufficient detail is included to allow specialization of these structures by users who wish to write functions to fit specialized linear mixed models, such as models incorporating pedigrees or smoothing splines, that are not easily expressible in the formula language used by lmer.read more
Citations
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Why whales are big but not bigger: Physiological drivers and ecological limits in the age of ocean giants.
Jeremy A. Goldbogen,David E. Cade,Danuta M. Wisniewska,Jean Potvin,Paolo S. Segre,Matthew S. Savoca,Elliott L. Hazen,Elliott L. Hazen,Elliott L. Hazen,Max F. Czapanskiy,Shirel R. Kahane-Rapport,S. L. DeRuiter,Shane Gero,Pernille Tønnesen,William T. Gough,M. B. Hanson,M. M. Holt,Frants H. Jensen,Malene Simon,Alison K. Stimpert,Patricia Arranz,David Johnston,Douglas P. Nowacek,Susan E. Parks,Fleur Visser,Fleur Visser,Ari S. Friedlaender,Peter L. Tyack,Peter T. Madsen,Nicholas D. Pyenson,Nicholas D. Pyenson +30 more
TL;DR: Gigantism in whales is both driven and limited by prey capture and availability, and filter feeding provides an evolutionary pathway to extremes in body size that is not available to lineages that must feed on one prey at a time.
Journal ArticleDOI
The impact of the COVID-19 pandemic on European police officers: Stress, demands and coping resources.
Marie Ottilie Frenkel,Laura Giessing,Sebastian Egger-Lampl,Vana Hutter,Raôul R.D. Oudejans,Raôul R.D. Oudejans,Lisanne Kleygrewe,Emma Jaspaert,Henning Plessner +8 more
TL;DR: Preparing for a pandemic requires three primary paths: enacting unambiguous laws and increasing public compliance through media communication, being logistically prepared, and improving stress regulation skills in police training.
Journal ArticleDOI
Large-scale wearable data reveal digital phenotypes for daily-life stress detection
Elena Smets,Elena Smets,Emmanuel Rios Velazquez,Giuseppina Schiavone,Imen Chakroun,Ellie D'Hondt,Walter De Raedt,Jan Cornelis,Olivier Janssens,Sofie Van Hoecke,Stephan Claes,Ilse Van Diest,Chris Van Hoof,Chris Van Hoof +13 more
TL;DR: Digital phenotypes characterized by self-reported poor health indicators and high depression, anxiety and stress scores that are associated with blunted physiological responses to stress are identified to build personalized stress models for precision medicine.
Journal ArticleDOI
Role of somatostatin-positive cortical interneurons in the generation of sleep slow waves
TL;DR: Using chemogenetic and optogenetic approaches, the first evidence that links a specific class of inhibitory interneurons—somatostatin-positive cells—to the generation of slow waves during NREM sleep in freely moving mice is provided.
Journal ArticleDOI
Gender-related time course of sleep disturbances and psychological symptoms during the COVID-19 lockdown: A longitudinal study on the Italian population.
Federico Salfi,Marco Lauriola,Giulia Amicucci,Domenico Corigliano,Lorenzo Viselli,Daniela Tempesta,Michele Ferrara +6 more
TL;DR: The present study is the first large-scale longitudinal report of the sleep and mental health changes during the prolonged lockdown due to the COVID-19 outbreak and suggests that there is no “weaker gender” after a prolonged lockdown.
References
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TL;DR: Linear Mixed-Effects and Nonlinear Mixed-effects (NLME) models have been studied in the literature as mentioned in this paper, where the structure of grouped data has been used for fitting LME models.
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