2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/180127I summarize the results of a recent analysis where the cosmological effects of interactions of neutrinos with cold Dark Matter (DM) is investigated. This interaction produces diffusion-damped oscillations in the matter power spectrum, analogous to the acoustic oscillations in the baryon-photon fluid. I discuss the bounds from the Sloan Digital Sky Survey on the corresponding opacity defined as the ratio of neutrino-DM scattering cross section over DM mass, and compare with the constraint from observation of neutrinos from supernova 1987A.Talk given at the Neutrino Oscillation Workshop NOW2006, Otranto, Italy, September 9-16 2006Astrophysicstext