2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/52376First we briefly outline the general construction of Dp-brane models with dynamical tensions. We then proceed to a more detailed discussion of a modified string model where the string tension is related to the potential of (an external) world-sheet electric current. We show that cancellation of the pertinent conformal anomaly on the quantum level requires the dynamical string tension to be a square of a free massless world-sheet scalar field.10 pages; to appear in: "Fifth Workshop on Lie Theory and Applications in Physics", H.-D. Doebner and V. Dobrev (eds.), World Scientific (2004)High Energy Physics - Theorytext