If you have "()" as the variable name in a bugs object that is created by R2WinBUGS related function, you might find that a standard way of extracting the value of such variable might not work.
fm1 <- lmer(Reaction ~ Days + (DaysSubject), sleepstudy)
fm1.sim <- mcsamp(fm1)
You will find that you can get the simulated beta for Days by typing Days in R console (no quotation!!). But you cannot get (Intercept) by typing (Intercept) in R console. This is because R does not allow special character like "(" or "_" as a the variable name.
So in order to get (Intercept), we have to use "`".
3 hours ago