We obtain dS and AdS generalized Reissner-Nordstrom like black hole
geometries in a curved D3-brane frame-work, underlying a noncommutative gauge
theory on the brane-world. The noncommutative scaling limit is explored to
investigate a possible tunneling of an AdS vacuum in string theory to dS vacuum
in its low energy gravity theory. The Hagedorn transition is invoked into its
self-dual gauge theory to decouple the gauge nonlinearity from the dS geometry,
which in turn is shown to describe a pure dS vacuum.Comment: 7-page