[R-sig-ME] How to obtain t-values from mer objects

[Gang Chen]

I know how to obtain the fixed effects from a mer object:

> (fm1 <- lmer(Reaction ~ Days + (Days|Subject), sleepstudy))

> fixef(fm1)

or,

> getME(fm1, 'beta')

But how can I obtain the t-statistic values for the fixed effects?

Thanks,
Gang