Uncertaities due to convection and production of s-nuclei in massive   stars
  We have investigated the role of the convective overshooting on the production of s-nuclei during core He-burning phase in stellar models with different initial mass and metallicity ($15 \leq M_{ZAMS}/M_{\odot} \leq 25$; $10^{-4} \leq Z \leq 0.02$), considering a diffusive approach to model the convective overshooting. The results and their possible consequences on some open questions linked to the s-process weak component efficiency are discussed. 
M.L. Pumo, G. Contino, A. Bonanno, R.A. Zappal\`a
astro-ph.SR