We consider in this paper the existence and the asymptotic behavior of positive ground state solutions of the boundary value problem -Delta u = a(1)(x)u(alpha 1) + a(2)(x)u(alpha 2) in R-n, lim(|x|->infinity) u(x) = 0, where alpha(1), alpha(2) < 1 and alpha(1), alpha(2) are nonnegative functions in C-loc(gamma) (R-n), 0 < gamma < 1, satisfying some appropriate assumptions related to Karamata regular variation theory.