Maxwell's equal area law and the Hawking-Page phase transition

In this paper we study the phases of a Schwarzschild black hole in the Anti deSitter background geometry. Exploiting fluid/gravity duality we construct the Maxwell equal area isotherm T=T* in the temperature-entropy plane, in order to eliminate negative heat capacity black hole configurations. The construction we present here is reminiscent of the isobar cut in the pressure-volume plane which eliminates un-physical part of the Van der Walls curves below the critical temperature. Our construction also modifies the Hawking-Page phase transition. Stable black holes are formed at the temperature T > T*, while pure radiation persists for T< T*. T* turns out to be below the standard Hawking-Page temperature and there are no unstable black holes as in the usual scenario. Also, we show that in order to reproduce the correct black hole entropy S=A/4, one has to write a black hole equation of state, i.e. P=P(V), in terms of the geometrical volume V=4\pi r^3/3.Comment: 15 pages, 4 Figures. Accepted for publication in Journal of Gravit

Violence Reduction

The 1990s have seen a significant decline in the occurrence of violent crimes nationwide, especially in major metropolitan areas. Yet, the number of person-on-person crimes in which youth appear as either offenders or victims remains persistently high in Philadelphia. The homicide rate among young Philadelphians is five times higher than that for the U.S. population. Public, private and nonprofit organizations in Philadelphia are working together to set in motion a unique and promising partnership aimed at significantly reducing youth violence: Philadelphia's Youth Violence Reduction Project (YVRP). This report summarizes the acute need for public and private violence reduction partnerships, describes outstanding current efforts by city agencies and youth-serving organizations to help curb youth violence in Philadelphia and outlines the evolution of the YVRP project, its pilot program in the 24th Police District, and the larger potential it has for Philadelphia

Black holes production in self-complete quantum gravity

A regular black hole model, which has been proposed by Hayward, is reconsidered in the framework of higher dimensional TeV unification and self-complete quantum gravity scenario (Dvali, Spallucci). We point out the "quantum" nature of these objects and compute their cross section production by taking into account the key role played by the existence of a "minimal length" l_0. We show as the threshold energy is related to l_0. We recover, in the high energy limit, the standard "black-disk" form of the cross section, while it vanishes, below threshold, faster than any power of the invariant mass-energy \sqrt{-s}.Comment: 12 pages; 3 figures; accepted for publication in PL