2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/197629The predictions of the IBM two-body random ensemble are compared to empirical results on nuclei from Z=8 to 100. Heretofore unrecognized but robust empirical trends are identified and related both to the distribution of valence nucleon numbers and to the need for and applicability of specific, non-random interactions. Applications to expected trends in exotic nuclei are discussed.7 pages, 5 figures, revtex with eps figuresNuclear TheoryNuclear Experimenttext