  Gamow-Teller and Fermi transitions are considered in a HF+BCS+pnQRPA
theoretical framework. We show here how Gamow-Teller strength distributions can
be used in a search for signatures of nuclear deformation in neutron deficient
Pb, Hg and Po isotopes, as well as how Fermi transitions allow us to quantify
isospin mixing in some even Kr isotopes around N=Z.
