Thermal radiation in non-static curved spacetimes: quantum mechanical path integrals and configuration space topology

A quantum mechanical path integral derivation is given of a thermal propagator in non-static Gui spacetime. The thermal nature of the propagator is understood in terms of homotopically non-trivial paths in the configuration space appropriate to tortoise coordinates. The connection to thermal emission from collapsing black holes is discussed.Comment: 20 pages, major revised version, 9 figures, new titl

Indicator Bacteria Concentrations of Two Northwest Arkansas Streams in Relation to Flow and Season

Concentrations of indicator bacteria such as fecal coliform (FC) and fecal streptococcus (FS) are often used to assess the suitability of waters for their intended use(s) and to allocate resources for water quality improvement measures. There is evidence, however, that concentrations of FC and FS can be influenced by variables such as season and flow rate during sampling, which could lead to biased results. The objective of this study was to assess the impacts of season and flow rate on concentrations of FC and FS. Fecal indicator bacteria concentrations were measured for approximately three years at five sites on two Northwest Arkansas streams. Flow data were collected at two of the five sites. Land use in the basins draining the streams was primarily pasture (57-90%) and forest (6-40%). Significant seasonal influences on FC and FS concentrations were detected for all sampling sites, with the highest concentrations occurring in summer. On the two sites with flow data, flow rate generally had a significant effect on FC and FS concentrations during all seasons, with FC and FS concentrations increasing with flow rate. Ratios of FC and FS, which have been used in the past to differentiate between animal and human sources of fecal pollution, did not appear to reliably indicate the major sources of fecal indicator bacteria. The findings of this study suggest a potential for fixed sampling intervals to contribute to biased results. The issue of biased results might be avoided by sampling during times of year and flow conditions that support the intended use(s) of the waters

Utilitat de la metodologia de simulació per adquirir competències en habilitats de comunicació

Podeu consultar la Vuitena trobada de professorat de Ciències de la Salut completa a: http://hdl.handle.net/2445/66524Metodología: Se describen los talleres y seminarios de simulación empleados desde el año académico 2010-11 en la Facultad de Medicina de la Universidad de Barcelona, que se ofrecen a los alumnos a partir de 2 año de grado, con el fin de ofrecer a los alumnos de forma transversal la adquisición y refuerzo continuo de competencias en habilidades de comunicación. Siguiendo las definiciones del Libro Blanco de las Facultades de Medicina y de la Guía de la Facultad de Medicina de la UB, se ofrece formación en los siguientes aspectos de la competencia de comunicación: • Escuchar con atención, obtener y sintetizar información pertinente acerca de los problemas que aquejan al enfermo, y comprender el contenido de esta información. • Comunicación de malas noticias • Obtener un consentimiento Informado • Comunicación entre profesionales Se describen el nivel de aprendizaje, el personal docente requerido, la duración de los seminarios o talleres, los objetivos docentes, el material necesario en cada actividad y el año de la formación de grado en que se aplica. Se describe la utilización de la estrategia de feed-back para la autoevaluación de la actividad práctica, empleando grabaciones de los talleres y simulaciones de los grupos de alumnos. Se describe así mismo, las encuestas empleadas para la evaluación por el docente y los compañeros de clase de las actividades de simulación y la metodología empleada de evaluación de los seminarios y su calificación dentro de la nota final de cada asignatura. Finalmente se describen las asignaturas optativas existentes en la Facultad de Medicina de la UB para reforzar las habilidades de comunicación y los planes futuros de desarrollo de actividades formativas complementarias y de refuerzo y las propuestas evaluativas de la competencia

Quantum mechanical path integrals and thermal radiation in static curved spacetimes

The propagator of a spinless particle is calculated from the quantum mechanical path integral formalism in static curved spacetimes endowed with event-horizons. A toy model, the Gui spacetime, and the 2D and 4D Schwarzschild black holes are considered. The role of the topology of the coordinates configuration space is emphasised in this framework. To cover entirely the above spacetimes with a single set of coordinates, tortoise coordinates are extended to complex values. It is shown that the homotopic properties of the complex tortoise configuration space imply the thermal behaviour of the propagator in these spacetimes. The propagator is calculated when end points are located in identical or distinct spacetime regions separated by one or several event-horizons. Quantum evolution through the event-horizons is shown to be unitary in the fifth variable.Comment: 22 pages, 10 figure

Structural premise of selective deubiquitinase USP30 inhibition by small-molecule benzosulfonamides

Dampening functional levels of the mitochondrial deubiquitylating enzyme Ubiquitin-specific protease 30 (USP30) has been suggested as an effective therapeutic strategy against neurodegenerative disorders such as Parkinson’s Disease. USP30 inhibition may counteract the deleterious effects of impaired turnover of damaged mitochondria, which is inherent to both familial and sporadic forms of the disease. Small-molecule inhibitors targeting USP30 are currently in development, but little is known about their precise nature of binding to the protein. We have integrated biochemical and structural approaches to gain novel mechanistic insights into USP30 inhibition by a small-molecule benzosulfonamide-containing compound, USP30inh. Activity-based protein profiling mass spectrometry confirmed target engagement, high selectivity, and potency of USP30inh for USP30 against 49 other deubiquitylating enzymes in a neuroblastoma cell line. In vitro characterization of USP30inh enzyme kinetics inferred slow and tight binding behavior, which is comparable with features of covalent modification of USP30. Finally, we blended hydrogen–deuterium exchange mass spectrometry and computational docking to elucidate the molecular architecture and geometry of USP30 complex formation with USP30inh, identifying structural rearrangements at the cleft of the USP30 thumb and palm subdomains. These studies suggest that USP30inh binds to this thumb–palm cleft, which guides the ubiquitin C terminus into the active site, thereby preventing ubiquitin binding and isopeptide bond cleavage, and confirming its importance in the inhibitory process. Our data will pave the way for the design and development of next-generation inhibitors targeting USP30 and associated deubiquitinylases