String creation in cosmologies with a varying dilaton
  FRW solutions of the string theory low-energy effective actions are described, yielding a dilaton which first decreases and then increases. We study string creation in these backgrounds and find an exponential divergence due to an initial space-like singularity. We conjecture that this singularity may be removed by the effects of back-reaction, leading to a solution which at early times is de Sitter space. 
Joshua J. Friess (Princeton University), Steven S. Gubser (Princeton   University), and Indrajit Mitra (UC Berkeley & LBNL, ...