  We present measurements of the fluctuational excess conductivity at 48 GHz
and 24 GHz in YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ films above the transition
temperature. The measurements depart from the gaussian prediction for
finite-frequency fluctuational conductivity. We focus on the region not too
close to $T_{c}$, where the real part of the excess conductivity drops much
faster than the prediction of the gaussian model. We calculate the dynamic
excess conductivity within a Ginzburg-Landau approach. In the calculation we
insert a short-wavelength cutoff of the order of the inverse coherence length,
in order to suppress high-momentum modes. The excess conductivity of all
samples measured can be described very well by the modified model.
