Percolation approach to phase transitions in high energy nuclear   collisions
  We study continuum percolation in nuclear collisions for the realistic case in which the nuclear matter distribution is not uniform over the collision volume, and show that the percolation threshold is increased compared to the standard, uniform situation. In terms of quark-gluon plasma formation this means that the phase transition threshold is pushed to higher energies. 
A. Rodrigues, R. Ugoccioni and J. Dias de Deus (CENTRA, IST Lisbon)