Upper row: radiative accelerations (solid lines) and gravity (dotted lines); center row: wind velocities (dashed lines) and diffusion velocities toward the exterior (solid lines) and toward the interior (dotted lines); lower row: interior concentrations as a fraction of original ones. These quantities are shown at four different ages for a 0.8 M_⊙ model with Ṁ = 10^-12 M_⊙ yr^-1. The vertical lines indicate the position of the bottom of the SCZ. The ages are identified in the figure.