2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48736I discuss in some detail the spin-flavour conversions of neutrinos in the almost isotopically neutral region of collapsing stars along with the resulting experimental signatures. In particular, I show that for realistic magnetic field strength, the observable effects may exist for neutrino magnetic moment, $μ\sim (2-3)\times 10^{-14}μ_B$ ($μ_B$ is the Bohr magneton) with relevant neutrino mass squared difference, $Δm^2 \sim (10^{-9}-10^{-8}) eV^2$.5 pages, Latex (uses sprocl.sty), No figures, Talk presented at Second Meeting on New Worlds in Astroparticle Physics (NW 98),Faro, Portugal, 3-5 September, 1998 (to appear in its proceedings)High Energy Physics - PhenomenologyAstrophysicstext