Effects of Rotation on Presupernovae Models
  We show that rotation strongly affects the nature of the supernova progenitor (blue/red supergiant or Wolf--Rayet star), and thus the supernova types. In particular our models well reproduce the variations of the number ratio SNIb/Ic to SNII with metallicity. Rotation also produces envelope enrichments of the N/C ratio, and increases the size of the CO cores. We show the evolution of the specific angular momentum up to the preSN stage and make comparison with neutron stars. We suggest that the rare WO stars, preferentially formed at low metallicity, are the progenitors of GRB. 
Georges Meynet, Raphael Hirschi, & Andr\'e Maeder