Extrapolation of perturbative nucleon spin fluctuation rates seems to
suggest a strong suppression of weak interactions in supernova cores.
We derive a generalized f sum rule for the dynamical spin-density stru
cture function which relates the spin fluctuation rate to the average
nuclear interaction energy. For a bremsstrahlung-like structure functi
on profile we show that, instead of strongly decreasing, the neutrino
scattering cross section is roughly density independent, and axion emi
ssivities increase somewhat slower than the lowest order rates toward
the center of a hot supernova core.