  For background geometries whose metric contain a scale $\gamma$ we
reformulate the Born-Infeld
  D-brane action in terms of $\epsilon \equiv \gamma /(2\pi \alpha ')$.
  This may be taken as a starting point for various perturbative treatments of
the theory. We study two limits that arise at zeroth order of such
perturbations. In the first limit, that corresponds to the $g_s\to\infty$ with
$\epsilon$ fix, we find a "string parton" picture, also in the presense of some
background
  RR-fields. In the second limit, $\epsilon\to 0$, we find a topological model.
