Closed timelike curves and chronology protection in quantum and classical simulators

In principe, General Relativity seems to allow the existence of closed timelike curves (CTC). However, when quantum effects are considered, it is likely that their existence is prevented by some kind of chronological protection mechanism, as Hawking conjectured. Confirming or refuting the conjecture would require a full quantum theory of gravity. Meanwhile, the use of simulations could shed some light on this issue. We propose simulations of CTCs in a quantum system as well as in a classical one. In the quantum simulation, some restrictions appear that are not present in the classical setup, which could be interpreted as an analogue of a chronology protection mechanism.Comment: 6 pages, 4 figures. v2: published versio

Investigation of the light propagation in the human forearm

En col·laboració amb la Universitat Autònoma de Barcelona (UAB), la Universitat de Barcelona (UB) i l’Institut de Ciències Fotòniques (ICFO)In the present study it is investigated the applicability of spectrally resolved reflectance at a certain distance from the incident beam to determine the optical coefficients of multi-layered tissues. The main motivation of this investigation is to achieve the simplest multi-layered model as possible which describes, within a given tolerance range, the light propagation in human forearm and its optical properties. For getting to this end it is investigated which assumptions within the model are acceptable. We found out that the thickness of the first layer in a two-layered model is a parameter suitable to be fixed, as it does not have a large negative influence on the fitting-results, and that it is expected to obtain better results with an absolute fit than with a relative one. Furthermore, this investigation was complemented with experimental spectrally resolved reflectance measurements performed on tissue-simulating phantoms of known optical properties and on human forearms by using optical fibers at different distances to deliver and detect reflected light by means of a CCD camera

Validación de la versión española del Cuestionario Breve de Evitación Experiencial (BEAQ) en población clínica

The Brief Experiential Avoidance Questionnaire (BEAQ) has been suggested as the most appropriate instrument for measuring experiential avoidance. However, no Spanish validation has been published. The aim of this study was to validate a Spanish version of the BEAQ in a clinical sample treated at a community mental health unit. Methods: Participants (N = 332) completed the BEAQ as well as other self-report measures of experiential avoidance and psychopathology. Results: Internal consistency was satisfactory (α = .82). No statistically significant gender differences were found in the BEAQ scores. The data also showed high test-retest reliability after four to six weeks, acceptable concurrent validity with another experiential avoidance measure and acceptable convergent validity with the psychopathology measure. The principal component analysis, forcing the one factor solution proposed in the original scale, produced indicators similar to the English version of the BEAQ. Conclusions: These results firmly support the reliability and validity of this Spanish validation, stressing its usefulness as a measure of experiential avoidance in clinical populations.Antecedentes: el Cuestionario Breve de Evitación Experiencial (BEAQ) ha sido propuesto como el instrumento más adecuado para medir la evitación experiencial. Sin embargo, todavía no ha sido publicada ninguna validación en español. Por lo tanto, el objetivo del presente estudio ha sido la validación de una versión española del BEAQ, en una muestra clínica atendida en un Centro de Salud Mental Comunitario. Método: los participantes (N = 332) completaron el BEAQ, así como otras medidas de autoinforme de evitación experiencial y psicopatología. Resultados: la consistencia interna fue satisfactoria (α = .82). No se encontraron diferencias de género estadísticamente significativas en las puntuaciones del BEAQ. Los datos también mostraron una alta fiabilidad test-retest en un intervalo de cuatro a seis semanas, validez concurrente aceptable con otra medida de evitación experiencial y validez convergente aceptable con la medida de psicopatología. El análisis de componentes principales forzando a la solución de un factor, como se propuso en la escala original, obtuvo unos indicadores similares a los obtenidos en dicha versión inglesa. Conclusiones: los resultados confirman la adecuada fiabilidad y validez de la presente versión española del BEAQ, destacando su utilidad como medida de la evitación experiencial en población clínica

Development of the mirror system with humanoid robots

This project focuses in the concept of robot teleoperation and how to make it easier for any type of user. The use of robots requires in most of the cases high knowledge in the area which restrict their use to people specifically prepared for the task. For that reason it is essential for everybody the research for controlling robots using simpler techniques approaching the robotics for everybody. In this project, the user will use the simplest way to control the robot arms and using his/her own arms in the same way that he/she wants to move the robot arms. For reaching that goal, the project assumes the use of Microsoft Kinect device that capture everything the user does. Then a computer will process it and send the information to the robot, in this case a NAO robot. For that reason, the teleoperation is simple and possible even to old people or children. This type of interface opens the door to infinite possibilities and creates a solid foundation on which to establish future knowledge.Ingeniería Informátic

Tratamiento ambulatorio involuntario

Màster en Bioètica i Dret UB, VIII edició 2005-2007Discusión de las implicaciones bioéticas del tratamiento ambulatorio involuntari

Explotación industrial de pinnípedos en la factoría de Bahía Tethis (Tierra del Fuego, Argentina): Una aproximación zooarqueológica

Zooarchaeological data about a sea lion bone bead from Thetis Bay (Tierra del Fuego) is presented herein. They are the result of the activities carried out by a factory that exploited commercially colonies settled in the area during the 1940s.First field work on this bone accumulation pointed to present preliminary data on density, anatomical and taxonomic abundance, as well as taphonomic observations with the goal to discuss aspects related to site formation processes.Though the taxonomic composition can be considered almost monospecific and is interpreted that the most of these remains resulted from the tasks in the factory, the former indicators suggest the secondary nature of this record, which would have been accumulated by tides, transport in the discarded remains.Se presenta información zooarqueológica sobre una cama de huesos de pinnípedos, producto de las actividades de una factoría emplazada en Bahía Thetis (Tierra del Fuego), que explotó comercialmente las colonias emplazadas en la zona durante la década de 1940. Se describen los primeros trabajos de campo llevados a cabo en esta acumulación de huesos, cuyo objetivo fue obtener datos preliminares sobre su densidad, abundancia taxonómica y anatómica, así como efectuar ciertas observaciones tafonómicas tendientes a discutir aspectos vinculados a los procesos de formación de sitio. Si bien la composición taxonómicapuede considerarse casi mono específica y se interpreta que la gran mayoría de estos restos sonproducto de la faena en la factoría, los resultados inícialessugierenel carácter secundario de esta acumulación, la cual habría sido conformada por el trasporte ocasionado por las mareas de los restos descartados en la bahía

Magallanes, Fernando y Pacheco, Juan Antonio, Alemania y las culturas de Oriente Medio.

Sin resume

The Song of the Swallow

Sin resume

New Data on Pleistocene Faunal Exploitation at Piedra Museo (Central Plateau of Santa Cruz Province, Argentina)

Fil: Marchionni, Laura. División Arqueología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Vázquez, Martín. Museo del Fin del Mundo. Ushuaia; Argentin