Particle collisions near a three-dimensional warped AdS black hole

In this paper we consider the warped AdS$_{3}$ black hole solution of topologically massive gravity with a negative cosmological constant, and we investigate the possibility that it acts as a particle accelerator by analyzing the energy in the center of mass (CM) frame of two colliding particles in the vicinity of its horizon, which is known as the Ba\~nados, Silk and West (BSW) process. Mainly, we show that the critical angular momentum $(L_c)$ of the particle decreases when the parameter that controls the stretching deformation ($\nu$) increases. Also, we show that despite the particle with $L_c$ can exist for certain values of the conserved energy outside the horizon, it will never reach the event horizon; therefore, the black hole can not act as a particle accelerator with arbitrarily high CM energy on the event horizon. However, such particle could also exist inside the outer horizon being the BSW process possible on the inner horizon. On the other hand, for the extremal warped AdS$_{3}$ black hole, the particle with $L_c$ and energy $E$ could exist outside the event horizon and the CM energy blows up on the event horizon if its conserved energy fulfill the condition $E^{2}>\frac{(\nu^{2}+3)l^{2}}{3(\nu^{2}-1)}$, being the BSW process possible.Comment: 11 pages, 6 figure

Fermionic greybody factors of two and five-dimensional dilatonic black holes

We study fermionic perturbations in the background of a two and five-dimensional dilatonic black holes. Then, we compute the reflection and transmission coefficients and the absorption cross section for fermionic fields, and we show numerically that the absorption cross section vanishes in the low and high frequency limit. Also we find that beyond a certain value of the horizon radius $r_0$ the absorption cross section for five-dimensional dilatonic black hole is constant. Besides, we have find that the absorption cross section decreases for higher angular momentum, and it decreases when the mass of the fermionic field increases.Comment: Accepted in EPJ

El reto del envejecimiento y la complejidad farmacoterapéutica en el paciente VIH+

Objective: To describe the current knowledge and management of aging and pharmacotherapeutic complexity in HIV + patients. Method: A review of literature was carried out, including articles, originals or reviews, published in English or Spanish, from 2007 to 2017, which analysed the aging and pharmacotherapeutic complexity in HIV + patients. The terms «Polypharmacy»/«Polifarmacia», «Aging»/«Envejecimiento», «Frailty»/«Fragilidad», «Complejidad Farmacotera péutica»/«Medication Regimen Complexity» and «HIV»/«VIH» were combined. The review was carried out independently by two authors. The degree of agreement, according to the Kappa index, was analysed. Results: A total of 208 references were analysed, including, finally, only 68. An aging of the population and an increase in associated comorbidities have been identified, especially over 50 years-old. Immunological changes similar to those that are generated in a non-infected elderly population have been described. These conditions influencing the prescription of antiretroviral treatment, according to studies identified. In parallel, polypharmacy is increasingly present, being defined exclusively by the concomitant use of five drugs. Pharmacotherapeutic complexity, through the Medication Regimen Complexity Index, has begun to analyse and relate to health outcomes. There has been a need to know and apply concepts already known in non-HIV-aged population, such as deprescription, potentially inappropriate medication, cholinergic risk, although few results are available. Conclusions: There is a growing interest to know about the relationship between HIV and aging. Pharmacotherapeutic complexity is beginning to be used as a pharmacotherapeutic follow-up criterion due to its influence on health outcomes. It is necessary to manage and incorporate new concepts that help pharmacotherapeutic optimization in this population

Trends and cycles: How important are long- and short-run restictions? The case of Mexico

The document presents a test for the existence of binding long- and short-run (common trend-common cycle) restrictions in the dynamics of a set of Mexican macroeconomic variables. These restrictions are imposed in a VAR to decompose the series into their permanent and transitory components. The analysis shows that the magnitude of transitory (nominal) shocks is underestimated when such restrictions are not considered. In addition, we find that the timing and duration of recession and expansion periods are more accurately estimated when the trend-cycle decomposition is conducted with the imposition of cointegrating (long-run) and common feature (short-run) restrictions.