Sergio Silva Valenzuela

Proposal of an Integrated Index for Prioritization of Bridge Maintenance

The bridge rating used in bridge management systems commonly uses only a structural condition. Factors such as seismic risk, hydraulic vulnerability, and strategic importance are commonly used in an isolated fashion. However, these factors are relevant when there is no possibility to calibrate deterioration models. This research uses the needs-based framework for developing an integrated bridge index (IBI) as an aid for prioritization and decisions made on maintenance and rehabilitation of bridges. The index weighs the structure distresses, hydraulic vulnerability, seismic risk, and strategic importance of the bridge. The index was calibrated using visual inspection, survey to experts, and regression analysis. After, the index was applied on six bridges placed on a primary road of Chile. To organize visual inspection, bridge inventory, and compute IBI and rank bridges, a software was developed. The calibration of the IBI index shows a correlation of 98% and all the parameters obtained were significant. Further research is needed to integrate cost with the proposed index and allocate maintenance activities.

Validation of an assessment centre process for the selection of school leaders in Chile

ABSTRACT This study seeks to develop and validate an Assessment Centre (AC) tool for the evaluation and selection of school leaders, focusing on the identification of competencies that influence teaching and learning outcomes. International research supports the creation of Assessment Centres to select candidates for these roles, due to their superior predictive capacity over traditional methods. In this research, a model composed of four face-to-face instruments (an interview to assess competencies, a human resources exercise, a class observation exercise, and a strategic analysis exercise) was designed and validated which simulated the key tasks of a school principal. To establish the desired performance outcomes, three competencies and 15 indicators were selected, based on international and local standards. The analysis of performance results was obtained from a sample of 164 participants made up of teachers, school leaders and principals. The results suggest positive evidence for construct validity, concurrent criteria validity, and reliability between evaluators. Moreover, the data obtained from a sub-sample of principals, with three or more years of experience in their role, allowed for the association of their AC scores with the results of their school organisations, as measured by the National System for the Measurement of Educational Quality in the years 2013 and 2016.

Medición de riesgo y pronóstico en dermatología: estudios de cohorte y de casos y controles

La mayoria del conocimiento medico deriva del estudio profundo de los pacientes, sus enfermedades y el medio que los rodea. Cuando estamos cara a cara con los pacientes, muchas veces notamos asociaciones entre sus dolencias y posibles causas o potenciales factores de riesgo relacionados con estas enfermedades. Diversas preguntas e hipotesis surgen de esta observacion, y por medio de la investigacion clinica podemos evaluar la veracidad y la fuerza de estas relaciones. Para esclarecer estas dudas razonablemente, es necesario el diseno de estudios que permitan, basado en metodos estadisticos que disminuyan el sesgo y el azar, encontrar asociaciones reales entre las alteraciones que investigamos y sus causas o consecuencias. En este articulo, describiremos las caracteristicas de los principales estudios que permiten evaluar el riesgo y el pronostico en medicina, con el analisis de caracteristicas de su diseno, usos, ventajas y desventajas.