Diffusion in barred-spiral galaxies
  We characterize the radial migration of stars in the disk plane by
calculating the diffusion coefficient and the diffusion time-scale for a
bulge-disk N-body self-consistent system with a marginally-stable Toomre-Q
parameter. We find that diffusion is not constant in time, but follows the
evolution of the bar, and becomes maximum near the corotation region and in the
external disk region, where asymmetric patterns develop.
