2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/187284Unlike their lighter counterparts, most odd-odd N=Z nuclei with mass A > 40 40 have ground states with isospin T=1, suggesting an increased role for the isovector pairing interaction. A simple SO(5) seniority-like model of this interaction reveals a striking and heretofore unnoticed interplay between like-particle and neutron-proton isovector pairing near N=Z that is reflected in the number of each kind of pair as a function of A and T. Large scale shell-model calculations exhibit the same trends, despite the simultaneous presence of isoscalar pairs, deformation, and other correlations.8 pages + 2 postscript figures, in RevTeX. Discussion of isospin projection in HFB added. This version to appear in Phys. Lett. BNuclear Theorytext