2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48640We derive the nucleon non-perturbative sea-quark distributions coming from a composite model involving quarks and hadronic degrees of freedom. The model predicts a definite structured quark-antiquark asymmetry in the nucleon sea.4 pages, 2 fig.ps, uses sproc.sty. Presented in Quark Matter'97, Tsukuba (Japan) and in Hadron Physics'98, Florianopolis (Brazil). To appear in the ProceedingsHigh Energy Physics - Phenomenologytext