  For a $Q \cdot Q$ interaction the energy weighted sum rule for isovector
orbital magnetic dipole transitions is proportional to the difference $\sum
B(E2, isoscalar) - \sum B(E2, isovector)$, not just to $\sum B(E2, physical)$.
This fact is important in ensuring that one gets the correct limit as one goes
to nuclei, some of which are far from stability, for which one shell (neutron
or proton) is closed. In $0p$ shell calculations for the even-even Be isotopes
it is shown that the Fermion SU(3) model and Boson SU(3) model give different
results for the energy weighted scissors mode strengths.
