Predicted [N/O] values as a function of log g_C by the Geneva (left) and Bonn (right) groups. Initial stellar masses (in solar units) are indicated. Rotational velocities at the ZAMS are listed in Table 1. Each panel shows the data for the presumably single stars (circles), RV variables and SB1s (diamonds), and stars with unknown multiplicity status (right oriented triangles). Black empty and filled symbols represent the hotter stars studied with CMFGEN and the cooler stars studied with DETAIL/SURFACE, respectively. Blue, brown, and green filled circles represent stars with masses comprised in the ranges from 15 to 28, from 29 to 35, and higher than 35 M_⊙, respectively.