  The frequency dependent conductance of a two-dimensional quantum wire is
computed using a current conserving formalism. The correction to the
dc-conductance due to a time-dependent potential is related to the local
partial density of states which we compute numerically. The current
conservation is explicitly confirmed by computing the global density of states
and comparing it with a quantity which is related to the electron dwell time.
Our calculation clearly reveals the physical meaning of the various partial
density of states.
