  It has been predicted that the zero frequency density of states of YBCO in
the superconducting phase can display interesting anisotropy effects when a
magnetic field is applied parallel to the copper-oxide planes, due to the
diamagnetic response of the quasi-particles. In this paper we incorporate
paramagnetism into the theory and show that it lessens the anisotropy and can
even eliminate it altogether. At the same time paramagnetism also changes the
scaling with the square root of the magnetic field first deduced by Volovik
leading to an experimentally testable prediction. We also map out the analytic
structure of the zero frequency density of states as a function of the
diamagnetic and paramagnetic energies. At certain critical magnetic field
values we predict kinks as we vary the magnetic field. However these probably
lie beyond currently accessible field strengths.
