Results of the general analysis. From left to right: the Robitaille disk structure; the line predictions for HCO⁺, HCN, and CN (in red for the Robitaille model, green for the Isella model); and the Isella disk structure (when available). The sources from top to bottom are: CI Tau, CY Tau, DG Tau, DN Tau, and DO Tau. For the disk structures, filled contours correspond to the temperature profile (in K). The temperature levels are identical for all disks, designated at: 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 75, 100, 150, and 250 K. A color bar is provided in Fig. 9. The contour lines indicate the log H₂ number density (in cm^-3), indicated at whole number integrals from 3 (disk surface/edge) to 12 (typical midplane density). Models are only pictured for the disks included in the Robitaille and Isella samples. (Color plots are available online.)