2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/39512The collisions between accelerated protons and the photons present in cosmos can be a main source of high-energy neutrinos (E \geq 10^6 GeV) of all flavors above the atmospheric neutrino background. I discuss here the possibility of photohadronic production of high-energy cosmic tau neutrinos in an astrophysical site and study some of the effects of vacuum neutrino flavor mixing on their subsequent propagation. I also discuss the prospects for observations of these high-energy cosmic tau neutrinos in new large neutrino telescopes5 pages, Latex, talk given at YITP Workshop on Theoretical Problems related to Neutrino Oscillations, 28 February-01 March, 2000, Kyoto, Japan (to appear in its proceedings)High Energy Physics - PhenomenologyAstrophysicstext