  We investigate the conductance of a 1-D disordered conducting loop with two
contacts, immersed in a magnetic flux. We show the appearance in this model of
the Al'tshuler-Aronov-Spivak behaviour. We also investigate the case of a chain
of loops distributed with finite density: in this case we show that the
interference effects due to the presence of the loops can lead to the
delocalization of the wave function.
