Some Remarks on Theories with Large Compact Dimensions and TeV-Scale   Quantum Gravity
  We comment on some implications of theories with large compactification radii and TeV-scale quantum gravity. These include the behavior of high-energy gravitational scattering cross sections and consequences for ultra-high-energy cosmic rays and neutrino scattering, the question of how to generate naturally light neutrino masses, the issue of quark-lepton unification, the equivalence principle, and the cosmological constant. 
Shmuel Nussinov and Robert Shrock