Cosmological Solutions of Supergravity in Singular Spaces
  We study brane-world solutions of five-dimensional supergravity in singular spaces. We exhibit a self-tuned four-dimensional cosmological constant when five-dimensional supergravity is broken by an arbitrary tension on the brane-world. The brane-world metric is of the FRW type corresponding to a cosmological constant $\Omega_{\Lambda}={5/7}$ and an equation of state $\omega=-{5/7}$ which are consistent with experiment. 
Ph. Brax and A. C. Davis