A bidimensional cellular automaton model is used to simulate the process of evacuation of pedestrians in a room with fixed obstacles. A floor field is defined so that moving to a cell with lower floor field means approaching an exit door. The model becomes non-deterministic by introducing a ''panic'' parameter, given by a probability of not moving, and by a random choice to resolve conflicts in the update of pedestrian positions. Two types of exit doors are considered: single (where only one person can pass) and double (two persons can pass simultaneously). For a double door, the longest evacuation time turns out to occur for a very traditional location of the door. The optimum door position is determined. Replacing the double door by two single doors does not improve evacuation times noticeably. On the other hand, for a room without obstacles, a simple scaling law is proposed to model the dependence of evacuation time with the number of persons and exit width. This model fails when obstacles are present, as their presence introduces local bottlenecks whose effect outweighs the benefits of increasing door width beyond a certain threshold. r

Objective: The objective of this study is to describe the oral health status and the factors associated with oral health-related quality of life (OHRQoL) in people aged 65 and older institutionalized in Barcelona in 2009. Study Design: Cross sectional study in 194 elderly. The dependent variable was poor OHRQoL, according to the Geriatric Oral Health Assessment Index (GOHAI). The independent variables were socio-demographic data, last dental visit, subjective and objective oral health status. Robust Poisson regression analysis was used to determine the factors associated with OHRQoL as well as the strengths of association (Prevalence Ratios with respective confidence intervals at 95%). Results: According to GOHAI, 94 women (68.1%) and 36 men (64.3%) had poor OHRQoL. The average DMFT index (number of decayed, missing and filled teeth) was 22.8, with mean 10.2 remaining teeth. According to the Community Periodontal Index only 1.9% were healthy. 33.8% of the sample (35.5% of women and 30.4% of men) presented edentulism, 54.2% needed upper dental prostheses (51.1% of women and 60.7% of men) and 64.7% needed lower ones (61.6% of women and 71.4% of men). Only 7.2% had visited a dentist in the past year (8.8% of women and 3.6% of men). After fitting several multivariate adjusted robust Poisson regression models, poor OHRQoL was found to be associated to self-reporting problems with teeth or gums, self-reporting poor opinion about teeth/gums/denture and also associated to functional edentulism, needing upper denture, but not to socio-demographic factors or time since last dental visit. Conclusions: The study population has poor objective oral health. A high percentage has poor OHRQoL associated to subjective and objective oral health conditions. Dental care is required and these services should be included in the Spanish National Health System. Key words:Oral health, homes for the aged, elderly, self-assessment, quality of life, geriatric oral health assessment index (GOHAI).

Objetivo. Caracterizar el proceso de implementación, barreras y facilitadores de recomendaciones basadas en evidencia en el contexto del desarrollo de guías prácticas clínicas (GPC) generadas por el Ministerio de Salud de Chile, a fin de brindar propuestas para la optimización del proceso. Métodos. Estudio cualitativo del tipo “investigación-acción”. Se realizaron 19 entrevistas semiestructuradas y se armaron nueve grupos de discusión a distintos niveles del sistema público de salud chileno. El análisis se realizó mediante el software Atlas ti® y en forma manual, desde un marco de análisis de contenido, mediante la categorización y codificación de la información según dimensiones preespecificadas y con la inclusión de categorías emergentes cuando fue pertinente. Resultados El principal desafío de implementación de recomendaciones mencionado es la falta de un proceso explícito y estructurado. Los actores del sistema de salud reconocen dificultades dependientes del contexto al momento de usar las recomendaciones. En esta experiencia inédita de revisión institucional, los participantes sugirieron una serie de estrategias a poner en práctica para superar dichos desafíos, representadas en un flujograma de gestión optimizada para el desarrollo e implementación de GPC. El mismo proceso ha permitido tomar conciencia de la importancia de la implementación de GPC en Chile. Conclusión. Tras caracterizar el proceso de implementación, barreras y facilitadores se articuló un plan de implementación de recomendaciones que permitiría orientar y monitorizar dicho proceso. Hacer partícipes del proceso de revisión a informantes claves dentro y fuera del Ministerio de Salud facilitaría la implementación de estrategias y la introducción de mejoras al proceso de desarrollo de GPC. Estudios de este tipo deberían ser realizados en médicos y pacientes para complementar la información recogida.

The complex behavior that occurs when traffic lights are synchronized is studied for a row of interacting cars. The system is modeled through a cellular automaton. Two strategies are considered: all lights in phase and a "green wave" with a propagating green signal. It is found that the mean velocity near the resonant condition follows a critical scaling law. For the green wave, it is shown that the mean velocity scaling law holds even for random separation between traffic lights and is not dependent on the density. This independence on car density is broken when random perturbations are considered in the car velocity. Random velocity perturbations also have the effect of leading the system to an emergent state, where cars move in clusters, but with an average velocity which is independent of traffic light switching for large injection rates.

Se presenta el caso de un paciente de sexo masculino, 29 años de edad, insuficiente renal crónico, con hiperparatiroidismo secundario y múltiples lesiones osteolíticas en las estructuras craneomaxilofaciales, diagnosticadas histológicamente como lesiones de células gigantes. La lesión de mayor tamaño afecta al maxilar superior, estructura raramente comprometida por este tipo de lesiones. Este tumor pardo produce gran deformidad facial y compromiso del piso orbitario, seno maxilar y fosa nasal correspondiente. No se evidenció regresión tumoral tras la paratiroidectomía y la normalización de los niveles de calcio séricos. Finalmente se realiza el remodelamiento quirúrgico del tumor pardo maxilar, con ausencia de recurrencia durante 7 años