  The notion of Lorentz violation in four dimensions is extended to a
5-dimensional brane-world scenario by utilizing a dynamical vector field
assumed to point in the bulk direction, with Lorentz invariance holding on the
brane. The cosmological consequences of this theory consisting of the time
variation in the gravitational coupling $G$ and cosmological term $\Lambda_4$
are explored. The brane evolution is addressed by studying the generalized
Friedmann and Raychaudhuri equations. The behavior of the expansion scale
factor is then considered for different possible scenarios where the bulk
cosmological constant is zero, positive or negative.
