We study the decay of I(t) = integral u(., t) where u is a nonnegative solu
tion to
u(t) - Delta u + \del u\(q) = 0
in R-n x R+ with n greater than or equal to 1. If 1 less than or equal to q
less than or equal to n+2/n+1 then I(t) --> 0 if I(0) < infinity and (t>0)
inf I(t) > 0 if q n+2/n+1.