  The transport through a quantum wire with a side coupled quantum dot is
studied. We use the X-boson treatment for the Anderson single impurity model in
the limit of $U=\infty $. The conductance presents a minimum for values of T=0
in the crossover from mixed-valence to Kondo regime due to a destructive
interference between the ballistic channel associated with the quantum wire and
the quantum dot channel. We obtain the experimentally studied Fano behavior of
the resonance. The conductance as a function of temperature exhibits a
logarithmic and universal behavior, that agrees with recent experimental
results.
