The Coulomb 1/r-interaction plays an important role in quantum wires.
We study the interplay between this long range interaction and impurit
y. For a single band quantum wire, we find that the transport properti
es are strongly modified. The linear conductance G is found to vanish
with temperature as G similar to exp[-vln(3/2)(1/T)] and the current-v
oltage characteristics acquires a threshold-like behavior.