  We present results of a lattice simulation of quantum chromodynamics with two
degenerate flavors of dynamic Wilson fermions at $6/g^2=5.3$ at each of two
dynamical fermion hopping parameters, $\kappa=0.1670$ and 0.1675, corresponding
to pion masses in lattice units of about 0.45 and 0.31. The simulations include
three other values of valence quark mass, in addition to the dynamical quarks.
We present calculations of masses and of the decay constants of vector mesons
and of pseudoscalars, including the D-meson decay constant. The effects of sea
quarks on matrix elements and spectroscopy are small.
