[R] removing random effect from nlme or using varPower() in nls

[Michael A. Gilchrist]

Hello,

I've been fitting a random effects model using nlme to some data, but I am 
discovering that the variation in my random effect is very small.  As a result, 
I would like to replace it as a fixed effect (i.e. essentially fit the same 
model but with no random effect).

As I understand it I could do this using nls(), but I'm using a number of 
options such as weights = varPower() which I am at a loss on how to implement 
in that framework.

Is there a way to use nlme but with out a random effect? (a bit absurd, I 
realize, but I have the syntax working...)

Alternatively, is there a way to use "weights = varPower()" with nls?

Any help would be appreciated.

Sincerely,

Mike