2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/82518The effective masses and sizes of N(939), $Δ(1232)$ and N(1440) in nuclear medium are calculated for a model in which quarks are subjected to a confinement force quenched by the scalar part of nuclear interactions. At the nuclear matter density, the nucleon swells by 50\% relative to the free nucleon. The masses of $Δ(1232)$ and N(1440) decrease in nuclear medium more than the nucleon, so that the pion requires less energy to excite them in nuclear medium than it does for a free nucleon.9 pages (2 figures not included, hard copy available upon request), SUT-AS-930801Nuclear Theorytext