2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/40835We give a brief summary of present bounds on the size of possible extra-dimensions as well as the string scale from collider experiments.11 pages, 4 figures, uses lathuile.sty . Talks given by I.A. at La Thuile2001 and by K.B. at Moriond2001High Energy Physics - Phenomenologytext