can model on a phenomenological level matter creation in the early Universe [@ChJa97]. Exact causal viscous cosmologies with $\xi \sim \rho ^{s},s\neq 1/2$ have been considered in Ref. [@MaHa99a].

Because of technical reasons, most investigations of dissipative causal cosmologies have assumed Friedmann-Robertson-Walker (FRW) symmetry (i.e. homogeneity and isotropy) or small perturbations around it [@MaTr97]. The Einstein field equations for homogeneous models with dissipative fluids can be decoupled and therefore are reduced to an autonomous system of first order ordinary differential equations, which can be analyzed qualitatively [@CoHo95].

The role of a transient bulk viscosity in a FRW space-time with decaying vacuum has been discussed in [@AbVi97]. Models with causal bulk viscous cosmological fluid have been considered recently [@ArBe00]. They obtained both power-law and inflationary solutions, with the gravitational constant an increasing function of time. The dynamics of a viscous cosmological fluids in the generalized Randall-Sundrum model for an isotropic brane were considered in [@Chen01]. The renormalization group method was applied to the study of homogeneous and flat FRW Universes, filled with a causal bulk viscous cosmological fluid, in [@Be03]. A generalization of the Chaplygin gas model, by assuming the presence of a bulk viscous type dissipative term in the effective 