Cosmological constraints for a two brane-world system with single   equation of state
  We present the study of two 3-brane system embedded in a 5-dimensional space-time in which the fifth dimension is compactified on a $S^{1}/Z_{2}$ orbifold. Assuming isotropic, homogeneous, and static branes, it can be shown that the dynamics of one brane is dominated by the other one when the metric coefficients have a particular form. We study the resulting cosmologies when one brane is dominated by a given single-fluid component. 
Juan L. Perez, Ruben Cordero and L. Arturo Urena-Lopez
gr-qc hep-ph