Segregation-induced grain boundary electrical potential in ionic oxide materials: A first principles model

A first principles continuum analytical model for cationic segregation to the grain boundaries in complex ceramic oxides is presented. The model permits one to determine the electric charge density and the segregation-induced electric potential profiles through the grain and can be extrapolated to the range of nanostructured grain sizes. The theoretical predictions are compared with existing data for yttria-stabilized tetragonal zirconia polycrystals. The implications for physical properties (mainly high temperature plasticity and hardening behaviour) are then discussed.Gobierno de España MAT2009-14351-C02-01, MAT2009-14351-C02-0

Some aspects of the family chromodorididae (opisthobranchia: nudibranchia) from brazil, with description of a new species

Algunos aspectos sobre la familia Chromodorididae (Opisthobranchia: nidibranchia) de Brasil, con la descripción de una nueva especie. – En este trabajo se hace un estudio de los nudibranquios pertenecientes a la familia Chromodorididae Bergh, 1891 encontrados durante varias campañas de muestreo en el litoral de Río de Janeiro, São Paulo y Fernando de Noronha (Brasil); fue estudiado un total de ocho especies de esta familia con descripción de una nueva especie, Chromodoris paulomarcioi n.sp. El taxón Hypselodoris picta lajensis Troncoso, García and Urgorri, 1998, es elevado a la categoría taxonómica de especie, y se proporcionan nuevas citas para algunas de las especies halladas

Managing Waiting Times to Predict No-shows and Cancelations at a Children’s Hospital

Purpose: Since long waits in hospitals have been found to be related to high rates of no-shows and cancelations, managing waiting times should be considered as an important tool that hospitals can use to reduce missed appointments. The aim of this study is to analyze patients’ behavior in order to predict no-show and cancelation rates correlated to waiting times. Design/methodology/approach: This study is based on the data from a US children’s hospital, which includes all the appointments registered during one year of observation. We used the call-appointment interval to establish the wait time to get an appointment. Four different types of appointment-keeping behavior and two types of patients were distinguished: arrival, no-show, cancelation with no reschedule, and cancelation with reschedule; and new and established patients. Findings: Results confirmed a strong impact of long waiting times on patients’ appointment-keeping behavior, and the logarithmic regression was found as the best-fit function for the correlation between variables in all cases. The correlation analysis showed that new patients tend to miss appointments more often than established patients when the waiting time increases. It was also found that, depending on the patients’ appointment distribution, it might get more complicated for hospitals to reduce missed appointments as the waiting time is reduced. Originality/value: The methodology applied in our study, which combines the use of regression analysis and patients’ appointment distribution analysis, would help health care managers to understand the initial implications of long waiting times and to address improvement related to patient satisfaction and hospital performance.Peer Reviewe

Transformation Optics Approach to Plasmon-Exciton Strong Coupling in Nanocavities

We investigate the conditions yielding plasmon-exciton strong coupling at the single emitter level in the gap between two metal nanoparticles. A quasi-analytical transformation optics approach is developed that makes possible a thorough exploration of this hybrid system incorporating the full richness of its plasmonic spectrum. This allows us to reveal that by placing the emitter away from the cavity center, its coupling to multipolar dark modes of both even and odd parity increases remarkably. This way, reversible dynamics in the population of the quantum emitter takes place in feasible implementations of this archetypal nanocavity.Comment: 5 pages, 4 figure

La distribución intraurbana de los inmigrantes en las ciudades españolas: un análisis de casos con SIG y técnicas cuantitativas

En las ciudades españolas cada vez es más habitual la existencia de áreas y espacios diferenciados por cuestiones sociales, económicas o étnicas. La vulnerabilidad a esta situación de determinados colectivos y la segregación residencial a la que se ven abocados algunos de ellos, especialmente los inmigrantes extranjeros, constituirán el objeto de estudio de esta investigación. Este artículo presenta, además, un doble objetivo. Por un lado, la realización de un análisis socioespacial mediante SIG. El análisis se apoyará en la aplicación de una serie de índices estadísticos de segregación residencial en los inmigrantes extranjeros de determinadas nacionalidades. Por otro lado, se examinarán sus patrones de localización a escala intraurbana en tres de las mayores ciudades españolas, Madrid, Barcelona y Sevilla. El análisis de estas ciudades será abordado desde una metodología comparativa y desde una perspectiva multi-escalar, que servirán para poner de manifiesto y valorar el patrón de distribución espacial del grupo mencionado

CO2 Concentration and Occupants’ Symptoms in Naturally Ventilated Schools in Mediterranean Climate

A large part of the school building stock in Andalusia lacks ventilation facilities, so that the air renewal of the classrooms is achieved through the building envelope (air infiltration) or the opening of windows. This research analyses the airtightness of the classrooms in Andalusia and the evolution of CO2 concentration during school hours through in situ monitoring. Pressurization and depressurization tests were performed in 42 classrooms and CO2 concentration was measured in two di erent periods, winter and midseason, to study the impact of the di erent levels of aperture of windows. About 917 students (11–17 years of age) were surveyed on symptoms and e ects on their health. The mean n50 values are about 7 h-1, whereas the average CO2 concentration values are about 1878 ppm, with 42% of the case studies displaying concentrations above 2000 ppm with windows closed

Estructuras conceptuales tridimensionales. Auxiliares en el aprendizaje de la química

Hasta ahora, el uso de mapas conceptuales constituye una valiosa experiencia didáctica, pudiéndose aplicar en todas las fases del proceso educativo. En el ámbito del aprendizaje, ha demostrado ser un instrumento eficaz para el logro del conocimiento. Sin embargo, existen algunos problemas a solucionar para lograr el uso correcto de los mapas conceptuales, puesto que muchas construcciones tienden a ser más descriptivas que explicativas. Con el propósito de facilitar el aprendizaje de los estudiantes de Química de la carrera de Ingeniería Química, se diseñaron y construyeron mapas conceptuales tridimensionales que permitiesen superar las deficiencias de conectores inadecuados o exceso de conceptos en un mapa bidimensional. Se presentan las estructuras obtenidas y los comentarios de los estudiantes