  We deduce the cosmogenic neutrino flux by jointly analysing ultra high energy
cosmic ray data from HiRes-I and II, AGASA and the Pierre Auger Observatory. We
make two determinations of the neutrino flux by using a model-dependent method
and a model-independent method. The former is well-known, and involves the use
of a power-law injection spectrum. The latter is a regularized unfolding
procedure. We then use neutrino flux bounds obtained by the RICE experiment to
constrain the neutrino-nucleon inelastic cross section at energies inaccessible
at colliders. The cross section bounds obtained using the cosmogenic fluxes
derived by unfolding are the most model-independent bounds to date.
