Minimum shear condition for the MRI and evolutionary tracks of our models. Left panel: logarithm of the absolute value of the shear, q, as a function of the radius when X_c = 0.35 for model AM100 (black) and model AM005 (red). The values of q_min, MRI given by the expression in Eq. (6) are plotted as dotted lines. The grey zone covers the convective core of the stellar models. Right panel: HR diagram showing the evolutionary tracks during the MS for various models (see legends).