Universality in sandpiles
  We perform extensive numerical simulations of different versions of the sandpile model. We find that previous claims about universality classes are unfounded, since the method previously employed to analyze the data suffered a systematic bias. We identify the correct scaling behavior and conclude that sandpiles with stochastic and deterministic toppling rules belong to the same universality class. 
Alessandro Chessa, H. Eugene Stanley, Alessandro Vespignani, and   Stefano Zapperi