Luis de la Corte Ibáñez

D = 4 chiral string compactifications from intersecting branes

Intersecting Dp-branes often give rise to chiral fermions living on their intersections. We study the construction of four-dimensional chiral gauge theories by considering configurations of type II D(3+n)-branes wrapped on nontrivial n-cycles on T2n×(R2(3−n)/ZN), for n=1, 2, 3. The gauge theories on the four noncompact dimensions of the brane world-volume are generically chiral and nonsupersymmetric. We analyze consistency conditions (RR tadpole cancellation) for these models, and their relation to four-dimensional anomaly cancellation. Cancellation of U(1) gauge anomalies involves a Green–Schwarz mechanism mediated by RR partners of untwisted and/or twisted moduli. This class of models is of potential phenomenological interest, and we construct explicit examples of SU(3)×SU(2)×U(1) three-generation models. The models are nonsupersymmetric, but the string scale may be lowered close to the weak scale so that the standard hierarchy problem is avoided. We also comment on the presence of scalar tachyons and p...

Legitimación de la violencia y contexto: análisis textual del discurso de las FARC-EP

Resumen En este estudio se analizó el discurso de las FARC-EP durante un periodo de cinco años. Los resultados muestran la existencia de dos momentos discursivos claramente diferenciados que se asocian a las modificaciones producidas en el contexto político, especialmente en las relaciones entre ese grupo y el gobierno colombiano. Pero los datos de este trabajo revelan que esos cambios en el discurso son meramente estratégicos ya que en ambos periodos están presentes, aunque bajo fórmulas retóricas distintas, los argumentos que legitiman la existencia de ese grupo armado.

Why Do Links Between Terrorism and Crime Increase

This chapter examines the nexus terror-crime and the various insights in the field, its possible forms and the main criminal activities involved. Special attention is given to the causes that enable and prompt terrorist involvement in criminal acts and relationships with criminal groups. A model about them is proposed. Then, there is an additional revision of the endogenous and exogenous factors that can facilitate the interaction between terrorist and criminal actors. Then, consequences that could arise from the convergence between terrorism and common and organised criminality are reviewed.