Una mirada antropológica sobre el conflicto, la desigualdad y los procesos de reinserción social en Colombia

For more than half of a century, Colombia has been living in a state of violence, a nationwide political violence. As the time goes by, this situation gets even worse. Now the violence is implanted for different interests, such as personal, political, social and economical interests. For this reason, the information for this thesis was gathered from the time of the independence, through the era of violence until today; considering a reflection that begins with the perspective of Marx, passing by a theoretical compilation of the conflict, with an anthropological, psychological, biological and sociological perspective. In addition, different theories about violence have been studied to recognize the ideological approach of the different armed movements that have emerged in Colombia. Statistical, economical and social data including class struggle, social stratification, exclusion and gender perspective among others, have been considered from an anthropological and interdisciplinary approach for studying the violence. A strong interest in the social reintegration process, through an ethnographic study, based on the actors backgrounds, their lives, experiences and their geographical location have provided information that will allow to know the reality of those who are living in the process, those who survive it and those who go on with their lives in society, and those who after doing it return to the armed groups. Population displaced by violence, refugees, has contributed to this study about their possibilities to return to the society or to be excluded by it. With this purpose, a theoretical and a documentary analysis as well as fieldwork have been done, trying to bring forward tools and guidelines to make some progress in developing effective solutions for social integration of Colombian armed conflict victims.

On neutron stars in ƒ (R) theories: Small radii, large masses and large energy emitted in a merger

In the context of ƒ (R) gravity theories, we show that the apparent mass of a neutron star as seen from an observer at infinity is numerically calculable but requires careful matching, first at the star’s edge, between interior and exterior solutions, none of them being totally Schwarzschild-like but presenting instead small oscillations of the curvature scalar R; and second at large radii, where the Newtonian potential is used to identify the mass of the neutron star. We find that for the same equation of state, this mass definition is always larger than its general relativistic counterpart. We exemplify this with quadratic R^2 and Hu-Sawicki-like modifications of the standard General Relativity action. Therefore, the finding of two-solar mass neutron stars basically imposes no constraint on stable ƒ (R) theories. However, star radii are in general smaller than in General Relativity, which can give an observational handle on such classes of models at the astrophysical level. Both larger masses and smaller matter radii are due to much of the apparent effective energy residing in the outer metric for scalar-tensor theories. Finally, because the ƒ (R) neutron star masses can be much larger than General Relativity counterparts, the total energy available for radiating gravitational waves could be of order several solar masses, and thus a merger of these stars constitutes an interesting wave source.

Equivalence of quantum field theories related by the θ-exact Seiberg-Witten map

The equivalence of the noncommutative U(N) quantum field theories related by the θ-exact Seiberg-Witten maps is, in this paper, proven to all orders in the perturbation theory with respect to the coupling constant. We show that this holds for super Yang-Mills theories with N=0, 1, 2, 4 supersymmetry. A direct check of this equivalence relation is performed by computing the one-loop quantum corrections to the quadratic part of the effective action in the noncommutative U(1) gauge theory with N=0, 1, 2, 4 supersymmetry.