complex residual variance

Hi all,

I'm not a frequent user of Lme4 and I have the habit to use mlwin for
multilevel analyses. Nevertheless I'm willing to master lme4 further.

In my research I'm often faced with the situation where level 1 variance (or
residual variance in the mixed effects framework) isn't constant. E.g. I
have longitudinal data on children, with multiple measurements
(observations) of these children at a certain moment. As children get older
these measurements seem to vary more and more. So the residual variance
itself is a function of time. As a consequence there is heteroscedasticity.
?Is there a possibility to explicitly model this in lme4? I know how to do
it in mlwin, but is it possible in lmer?