  We update our estimates of charged and neutral current neutrino total cross
sections on isoscalar nucleons at ultrahigh energies using a global (x, Q^2)
fit, motivated by the Froissart bound, to the F_2 (electron-proton) structure
function utilizing the most recent analysis of the complete ZEUS and H1 data
sets from HERA I. Using the large Q^2, small Bjorken-x limits of the "wee"
parton model, we connect the ultrahigh energy neutrino cross sections directly
to the large Q^2, small-x extrapolation of our new fit, which we assume
saturates the Froissart bound. We compare both to our previous work, which
utilized only the smaller ZEUS data set, as well as to recent results of a
calculation using the ZEUS-S based global perturbative QCD parton distributions
using the combined HERA I results as input. Our new results substantiate our
previous conclusions, again predicting significantly smaller cross sections
than those predicted by extrapolating pQCD calculations to neutrino energies
above 10^9 GeV.

High Energy Physics - Phenomenology;High Energy Astrophysical Phenomena