Nonconservation of the Quantum Number K and Phase Transitions in Rapidly   Rotating Nuclei
  Three different effects observed in experiments with rotating nuclei--backbending, noncollective quadrupole transitions between different levels of the same band, and transitions that occur, in rapidly rotating nuclei, from large-$K$ isomeric states immediately to the levels of a rotational band despite their strong forbiddenness in $K$--are explained in terms of nonconservation of the quantum number $K$ in such nuclei. 
A.M. Kamchatnov, V.G. Nosov