Light Cone Black Holes

When probed with conformally invariant matter fields, light cones in Minkowski spacetime satisfy thermodynamical relations which are the analog of those satisfied by stationary black holes coupled to standard matter fields. These properties stem from the fact that light cones are conformal Killing horizons stationary with respect to observers following the radial conformal Killing fields in flat spacetime. The four laws of light cone thermodynamics relate notions such as (conformal) temperature, (conformal) surface gravity, (conformal) energy and a conformally invariant notion related to area change. These quantities do not admit a direct physical interpretation in flat spacetime. However, they become the usual thermodynamical quantities when Minkowski is mapped, via a Weyl transformation, to a target spacetime where the conformal Killing field becomes a proper Killing field. In this paper we study the properties of such spacetimes. The simplest realisation turns out to be the Bertotti-Robinson solution, which is known to encode the near horizon geometry of near extremal and extremal charged black holes. The analogy between light cones in flat space and black hole horizons is therefore strengthened. The construction works in arbitrary dimensions; in two dimensions one recovers the Jackiv-Teitelboim black hole of dilaton gravity. Other interesting realisations are also presented.Comment: 23 pages, 7 figures; v2: typos corrected, matches published versio

Light Cone Thermodynamics

We show that null surfaces defined by the outgoing and infalling wave fronts emanating from and arriving at a sphere in Minkowski spacetime have thermodynamical properties that are in strict formal correspondence with those of black hole horizons in curved spacetimes. Such null surfaces, made of pieces of light cones, are bifurcate conformal Killing horizons for suitable conformally stationary observers. They can be extremal and non-extremal depending on the radius of the shining sphere. Such conformal Killing horizons have a constant light cone (conformal) temperature, given by the standard expression in terms of the generalisation of surface gravity for conformal Killing horizons. Exchanges of conformally invariant energy across the horizon are described by a first law where entropy changes are given by $1/(4\ell_p^2)$ of the changes of a geometric quantity with the meaning of horizon area in a suitable conformal frame. These conformal horizons satisfy the zeroth to the third laws of thermodynamics in an appropriate way. In the extremal case they become light cones associated with a single event; these have vanishing temperature as well as vanishing entropy.Comment: 30 pages, 5 pictures; V_2: a problem in the proof of the first law has been corrected. Results remain unchanged. Geometric interpretation and presentation improved; V_3: matches published versio

Slim SUSY

The new SM-like Higgs boson discovered recently at the LHC, with mass $m_h \simeq$ 125 GeV, as well as the direct LHC bounds on the mass of superpartners, which are entering into the TeV range, suggest that the minimal surviving supersymmetric extension of the SM (MSSM), should be characterized by a heavy SUSY-breaking scale. Several variants of the MSSM have been proposed to account for this result, which vary according to the accepted degree of fine-tuning. We propose an alternative scenario here, Slim SUSY, which contains sfermions with multi-TeV masses and gauginos/higgsinos near the EW scale, but it includes the heavy MSSM Higgs bosons ($H^0$, $A^0$, $H^\pm$) near the EW scale too. We discuss first the formulation and constraints of the Slim SUSY scenario, and then identify distinctive heavy Higgs signals that could be searched at the LHC, within scenarios with the minimal number of superpartners with masses near the EW scale.Comment: 16 pages, 6 figures. Section 2 has been restructured, with a new subsection and some comments added. This version matches the manuscript accepted in Physics Letters

Decays of H0/A0H^0/A^0 in supersymmetric scenarios with heavy sfermions

The recent discovery of a new boson at the LHC, which resembles a SM-like Higgs boson with $m_h=125$ GeV, is starting to provide strong guidelines into SUSY model building. For instance, the identification of such a state with the lightest CP-even Higgs boson of the MSSM ($h^0$), requires large values of $\tan\beta$ and/or heavy sfermions. One outcome of this result is the possibility to solve the SUSY flavor and CP problems by decoupling, which points towards some realization of Split-inspired SUSY scenarios, in which scalars are much heavier than gauginos and higgsinos. However, we argue here that the remaining Higgs bosons of the MSSM ($H^0$, $A^0$, $H^{\pm}$) do not have to be as heavy as the sfermions, and having them with masses near the EW scale does not pose any conflict with current MSSM constraints. We discuss then some SUSY scenarios with heavy sfermions, from a bottom-up approach, which contain the full Higgs sector, as well as a possible dark matter candidate, with masses near the EW scale, and identify distinctive signals from these scenarios that could be searched at the LHC.Comment: 25 pages, 12 figures. Title modified, one figure and some comments added, overall conclusions remained as previous versions. This last version matches the manuscript accepted in EPJ

Evolución y desarrollo de los complejos de rutenio como agentes antitumorales

En este trabajo se presenta una revisión sobre la evolución y desarrollo de los complejos de rutenio usados en terapia antitumoral. Teniendo en cuenta el diseño racional de fármacos organometálicos y la necesidad de aumentar la efectividad y disminuir la toxicidad de los complejos más usados hasta día de hoy, como son el cisplatino y sus análogos, el rutenio se presenta como el candidato más prometedor para elaborar nuevos complejos metálicos anticancerígenos. Por un lado, el rutenio debido a sus estados de oxidación, la geometría de sus coomplejos de coordinación y la naturaleza de sus ligandos, ofrece un amplio abanico de mecanismos de acción y de dianas terapéuticas a las que se dirige. Además, reduce los efectos secundarios que tantos problemas han ocasionado en la terapia antitumoral organometálica, debido a una mayor selectividad por las células cancerosas. Todo esto, ha despertado un interés por el estudio y el desarrollo de una gran cantidad de complejos basados en rutenio en los que las modificaciones de sus ligandos, en su mayoría aniónicos, han ocasionado una verdadera mejora en su actividad. Por otro lado, la nanotecnología está cada vez más presente en la terapia antitumoral, usando nanosistemas para administrar los complejos de rutenio (II). No obstante, aunque muchos complejos de rutenio han proporcionado resultados muy prometedores, tan sólo un numero reducido han conseguido demostrar eficacia en modelos in vivo y pasar a ensayos clínicos. En este trabajo de revisión nos hemos centrado en los complejos de rutenio en sus dos principales estados de oxidación (+2 y +3) y en el uso de la nanotecnología para mejorar la eficacia y seguridad de éstos, proporcionando una perspectiva de futuro en el uso de estos sistemas en la terapia antitumoralUniversidad de Sevilla. Grado en Farmaci

Design and Validation of a Questionnaire to Measure Future Spanish Teachers’ Perceptions of Cinema in Pre-School and Primary Education: Towards Active and Technological Learning

State of the art: Cinema, because of the eclectic nature of art, technology and mass media, can be manifested as an educational tool in the classroom. In this sense, the educational possibilities detected in the cinema are numerous. The pre-service teacher education in the figure of the teacher determines their educational resources. Purpose: The general objective of this study is to design and validate an instrument to measure the perceptions of students of Pre-School Teacher Degree and Primary Teacher Degree in Spanish universities about cinema as a teaching resource in Pre-School and Primary Education. Design/methodology: For this purpose, a systematic and planned process was developed for the design and validation of the Percepciones sobre las potencialidades del cine como recurso didáctico en las aulas de Infantil y Primaria ((PECID) (perceptions about the potentialities of cinema as a didactic resource in pre-school and primary classrooms)) questionnaire. Main findings: The results obtained showed a good content validity of 25 items after an expert judgement. On the other hand, a reliability of the internal consistency of the instrument of 0.978 was obtained. Furthermore, a three-factor structure was confirmed through factor analysis. Conclusions: It is concluded that the PECID questionnaire is a valid and reliable instrument to measure the perceptions of future teachers in Spain about using cinema as a resource for future teaching

Another episode of art trade. Sculptures from Andalusia in Tenerife during the early nineteenth century

En este artículo se estudian de forma pormenorizada cuatro esculturas de Tenerife que fueron contratadas en Andalucía entre 1800 y 1816, gracias al contacto de sus comitentes con agentes y compañías que comerciaban en Cádiz y Sevilla. La casuística tan diferente que describe cada encargo obliga a exponer su coyuntura histórica y artística de forma individualizada, resaltando por igual valores creativos y devocionales. Se propone la atribución de algunas obras a los imagineros Doménico Giscardi (1725-1805) y Juan de Astorga (1777-1849).In this essay we study four sculptures of Tenerife that were acquired in Andalusia between 1800 and 1816, through the contact with companies and agents who resided in Cadiz and Seville. Each religious sculpture has its own casuistry and it requires a commentary on its historical and artistic value individually, highlighting devotional and creative circumstances. We propose the attribution of them to the artists Doménico Giscardi (1725-1805) and Juan de Astorga (1777-1849)

Comparison of two ketamine/xylazine anesthesic protocols in pigs (Sus crofa domestica)

The pig (Sus scrofa domestica) is an animal used as an experimental model in surgical procedures. This makes the use of anaesthesia necessary. The present study constitutes a comparison between two different ketamine/xylazine concentration protocols. One protocol used ketamine 10% + xylazine 10% (high concentration), and the other ketamine 5% + xylazine 2% (low concentration). Concentrations were chosen since these are the most common presentations in the veterinary market. In the present experiments, twenty male and female pigs (Sus crofa domestica; 20 kg each), were assigned into two different groups. The first one was integrated by pigs treated with high concentration protocol (n = 10), and the second one, composed by pigs that received low concentration protocol (n = 10). Parameters measured were the time in which the animals were placed in sternal decubitus, and the heart rate. The effects of these drugs were considered not only specifically in its sedative effects, but also in the respiratory system. Based on these results, we conclude that the first protocol showed better results than the second one. The time in which the animals were placed in sternal decubitus was lower in the first one (p < 0.001). Differences between the effects on the respiratory system (p = 0.37) and sedative effects (p = 0.87) were not significant, even when focusing on the last measurement, higher concentration protocol was twenty percent (20%) more effective than lower.Fil: Guevara, Manuel Alejandro. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lorenzo Aquaro, Sofía Ana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; ArgentinaFil: Giai, Marcos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gargiulo, Pascual Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentina. Fundación Corporación Tecnológica Latinoamericana; Argentin