D. Commenges
Modeling the dynamics of biomarkers during primary HIV infection taking into account the uncertainty of infection date.
Fri, 01/07/2011 - 16:01 — SomNambulAuthors: D. Commenges, J. Drylewicz, J. Guedj, R. Thiébaut
Subjects: Applications
AbstractDuring primary HIV infection, the kinetics of plasma virus concentrations and
CD4+ cell counts is very complex. Parametric and nonparametric models have been
suggested for fitting repeated measurements of these markers. Alternatively,
mechanistic approaches based on ordinary differential equations have also been
proposed. These latter models are constructed according to biological knowledge
and take into account the complex nonlinear interactions between viruses and
cells. However, estimating the parameters of these models is difficult.Inference in HIV dynamics models via hierarchical likelihood.
Wed, 02/03/2010 - 16:01 — SomNambulAuthors: D. Commenges, D. Jolly, H. Putter, R. Thiebaut
Subjects: Statistics
AbstractHIV dynamical models are often based on non-linear systems of ordinary
differential equations (ODE), which do not have analytical solution.
Introducing random effects in such models leads to very challenging non-linear
mixed-effects models. To avoid the numerical computation of multiple integrals
involved in the likelihood, we propose a hierarchical likelihood (h-likelihood)
approach, treated in the spirit of a penalized likelihood. We give the
asymptotic distribution of the maximum h-likelihood estimators (MHLE) for fixed
effects, a result that may be relevant in a more general setting.
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