Robust nuclear observables and constraints on random interactions

The predictions of the interacting boson model two-body random ensemble are compared to empirical results on nuclei from Z = 8-100. Heretofore unrecog nized but robust empirical trends are identified and related both to the di stribution of valence nucleon:numbers and to the need for and applicability of specific, nonrandom interactions. Applications to expected trends in ex otic nuclei are discussed.