Excitations of the nucleon with dynamical fermions
  We measure the spectrum of low-lying nucleon resonances using Bayesian fitting methods. We compare the masses obtained in the quenched approximation to those obtained with two flavours of dynamical fermions at a matched lattice spacing. At the pion masses employed in our simulations, we find that the mass of the first positive-parity nucleon excitation is always greater than that of the parity partner of the nucleon. 
UKQCD collaboration, C.M. Maynard, LHP collaboration, D.G. Richards