Corrections in Type IIB Theory with Fluxes

We consider the Type IIB string theory in the presence of various extra 7/7-brane pairs compactified on a warped Calabi-Yau threefold that admits a conifold singularity. We demonstrate that the volume modulus can be stabilized perturbatively at a nonsupersymmetric AdS4/dS4 vacuum by the effective potential that includes the stringy (α) correction obtained by Becker et al. together with a combination of positive tension and anomalous negative tension terms generated by the additional 7-braneantibrane pairs.