  The unexpected "0.7" plateau of conductance quantisation is usually observed
for ballistic one-dimensional devices. In this work we study a quasi-ballistic
quantum wire, for which the disorder induced backscattering reduces the
conductance quantisation steps. We find that the transmission probability
resonances coexist with the anomalous plateau. The studies of these resonances
as a function of the in-plane magnetic field and electron density point to the
presence of spin polarisation at low carrier concentrations and constitute a
method for the determination of the effective g-factor suitable for disordered
quantum wires.
