Active-Sterile neutrino oscillations and BBN+CMBR constraints
  We show how active-sterile neutrino oscillations in the early Universe can play an interesting role in explaining the current observations of CMBR anisotropies and light element abundances. We describe different possible phenomenological scenarios in the interpretation of present data and how active-sterile neutrino oscillations can provide a viable theoretical framework. 
P. Di Bari and R. Foot