2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/201491We study a system of intersecting NS and D-branes in type IIA string theory in R^{9,1}. We show that the 3+1 dimensional non-supersymmetric theory at the intersection has unstable vacua which are long-lived in some regions of the parameter space of brane configurations, and disappear in others. We also comment on the relation of our construction to systems of D and anti D-branes wrapped around cycles of non-compact Calabi-Yau manifolds and to other related systems.39 pages, harvmac, 14 figuresHigh Energy Physics - Theorytext