The cosmic role of tachyon in the type 0 strings
  We present a new class of solution to the ten-dimensional type 0 effective action. Given a generic potential of tachyon field, there exist phases where tachyon is either frozen at local extremals or free to propagate along flat directions. In the latter phase, a cosmology model is proposed where the tachyon plays the role of time. 
Wen-Yu Wen