  We present results for a model that describes a quantum point contact. We
show how electron-electron correlations, within the unrestricted Hartree-Fock
approximation, generate a magnetic moment in the point contact. Having
characterized the magnetic structure of the contact, we map the problem onto a
simple one-channel model and calculate the temperature dependence of the
conductance for different gate voltages. Our results are in good agreement with
experimental results obtained in GaAs devices and support the idea of Kondo
effect in these systems.
