A direct connection can be made between mixing angles in negative parity baryons and the spin coupling of constituent quarks. The mixing angles do not depend on spectral data. These angles are recalculated for gluon exchange and pion exchange between quarks. The mixing determined for pion exchange is in disagreement with a calculation in the literature ͓Phys. Rep. 268, 263 ͑1996͔͒, but consistent with the results of another calculation ͓Phys. Rev. C 65, 045209 ͑2002͔͒ and with experiment. The experimental data on mixing are very similar to those derived from gluon exchange but substantially different from the values obtained for pion exchange. A preliminary estimate of spin orbit forces is found to give only small changes in these angles.

A direct connection can be made between mixing angles in negative parity baryons and the spin coupling of constituent quarks. The mixing angles do not depend on spectral data. These angles are recalculated for gluon exchange and pion exchange between quarks. For pion exchange the results of Glozman and Riska are corrected. The experimental data on mixing are very similar to those derived from gluon exchange but substantially different from the values obtained for pion exchange.

We discuss effects in beta decays at very low beta energies, of the order of the kinetic energies of atomic electrons. As the beta energy is lowered the atomic response changes from sudden to adiabatic. As a consequence, the beta decay rate increases slightly and the ejection of atomic electrons (shake off) and subsequent production of X rays is turned off. We estimate the transition energy, and the change in decay rate. The rate increase is largest in heavy atoms, which have a small Q value in their decay. The X ray switch-off is independent of Q value. P.A.C.S.:23.40.-s, 23.90.+w