Directed percolation with a single defect site
  In a recent study [arXiv:1011.3254] the contact process with a modified creation rate at a single site was shown to exhibit a non-universal scaling behavior with exponents varying with the creation rate at the special site. In the present work we argue that the survival probability decays according to a stretched exponential rather than a power law, explaining previous observations. 
Andre Cardoso Barato and Haye Hinrichsen
cond-mat.stat-mech