  Self-consistent Skyrme Hartree-Fock plus BCS calculations are performed to
generate potential energy curves (PEC) in various chains of Pd, Xe, Ba, Nd, Sm,
Gd, and Dy isotopes. The evolution of shapes with the number of nucleons is
studied in a search for signatures of E(5) and X(5) critical point symmetries.
It is shown that the energy barriers in the PECs are determined to a large
extent by the treatment of the pairing correlations.
