Cosmic Tau Neutrinos
  The 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 telescopes 
Athar Husain (Tokyo Metropolitan University, Japan)