Scale-invariant universal crossing probability in one-dimensional   diffusion-limited coalescence
  The crossing probability in the time direction is defined for an off-equilibrium reaction-diffusion system as the probability that the system of size L is still active at time t, in the finite-size scaling limit. Exact results are obtained for the diffusion-limited coalescence problem in 1+1 dimensions with periodic and free boundary conditions using empty interval methods. The crossing probability is a scale-invariant universal function of an effective aspect ratio, L^2/Dt, which is the natural scaling variable for this strongly anisotropic system. 
L. Turban (Universite Henri Poincare, Nancy 1)