Detecting Neutrinos from AGNs and Topological Defects with Neutrino   Telescopes
  We evaluate neutrino-nucleon cross section for energies up to $10^{21} eV$ in light of new information on the small-$x$ behavior of parton distributions. We give predictions for large underground neutrino telescope event rates for ultrahigh-energy neutrinos from Active Galactic Nuclei and from the decay of topological defects formed in the early Universe. 
Raj Gandhi, Chris Quigg, M. H. Reno and Ina Sarcevic