  The Interacting Boson Model with broken-pairs has been extended to include
mixed proton-neutron configurations in the fermion model space. The extended
version of the model has been used to describe high-spin bands in the
transitional nucleus $^{136}$Nd. Model calculations reproduce ten bands of
positive and negative parity states, including the two dipole high-spin
structures based on the $(\pi h_{11/2})^2$ $(\nu h_{11/2})^2$ configuration.
