title: how to model nested random effect in nlme package
body: <p>I have two factors in the linear mixed model. Factor A is treated as fixed effect, factor B is treated as random effect and nested into factor A. Can anyone tell me how to do this using nlme R package?</p>
  
  <p>I know that <code>lme( response~ factorA, random=~1|factorA/factorB)</code> is one way to model. however, this function treat factor A as random effect. </p>