Objective This study was aimed at comparing cardiorespiratory fitness (CF), measured as VO2 max, amongst school children exposed to varying levels of particulate matter (PM10), and air pollution in Bogotá, Colombia. Methods This was a cross-sectional study; it involved 1,045 children aged 7-12 attending four public schools served by different public transit routes and systems. Three schools were classified as being highly polluted (HP) and one slightly polluted (SP). The children and their parents were surveyed to collect data regarding their socio-demographic characteristics, physical activity habits and respiratory disease background. Objective measurements of weight and height were used to calculate the body mass index. VO2max was estimated using the 20-meter shuttle-run test, previously validated for Bogotá. Spirometry was performed on 435 children. Results After adjustment for covariates, no difference was found inVO2max between children attending SP or HP schools (girls SP 45.8 ml/kg/min vs HP 44.6 ml/kg/min, p=0.11;boys SP 47.2 ml/kg/min cf HP 48.2 ml/kg/min, p=0.41). Conclusions VO2max levels did not differ amongst children attending schools exposed to high compared to low levels of air pollution and PM. A longitudinal study assessing children’s VO2max levels in relation to exposure to highly-polluted areas is warranted.

Urban trees are a dominant natural element in cities; they provide important ecosystem services to urban citizens and help urban areas adapt to climate change. Many rationales have been proposed to provide a purpose for urban forest management, some of which have been ineffective in addressing important ecological and social management themes. Among these rationales we find a values-based perspective, which sees management as a process where the desires of urban dwellers are met. Another perspective is climate change adaptation, which sees management as a process where urban forest vulnerability to climate change is reduced and resilience enhanced. Both these rationales have the advantage of complementing, enhancing, and broadening urban forest management objectives. A critical analysis of the literature on public values related to urban forests and climate change adaptation in the context of urban forests is undertaken to discuss what it means to adopt these two issues in urban forest management. The analysis suggests that by seeing urban forest management as a process by which public values are satisfied and urban-forest vulnerabilities to climate change are reduced, we can place issues such as naturalization, adaptive management, and engaging people in management at the centre of urban forest management. Focusing urban forest management on these issues may help ensure the success of programs focused on planting more trees and increasing citizen participation in urban forest management.

This paper describes the experimental conditions in surface acoustic wave (SAW) designed on aluminum nitride (AlN) films grown on Si3 N 4 substrates by using pulsed laser deposition. Moreover it was studied the dependency of optical properties with temperature of deposition. The thickness, measured by profilometry technology, was 150 nm for all films. Moreover, SAW devices with a Mo/AlN/Si3N4 configuration were fabricated employing AlN buffer and Mo Channel.

Abstract: Algorithms for minimizing other regular criteria than the makespan in the Flexible Job-shop Scheduling Problem (FJSP) are rather scarce. In this paper, we propose a local search algorithm to optimize any regular criterion in the FJSP, which makes use of the disjunctive graph model to represent schedules and search for an optimal solution. Two neighborhood structures are proposed based on moving critical operations. Efficient conditions for testing the feasibility of moves are presented and new move evaluation functions are proposed. The efficiency of the algorithm is shown on instances of the classical job-shop scheduling problem with total weighted tardiness, as well as on instances of the FJSP with other regular criteria. Resumen: Algoritmos formulados para minimizar criterios regulares diferentes al makespan en el problema de scheduling job-shop flexible son realmente escasos. En este paper se propone un algoritmo de búsqueda local para optimizar cualquier criterio regular que utiliza una gráfica disyuntiva para representar soluciones y la forma para optimizar. Aquí se propone un test de factibilidad para el movimiento de operaciones críticas y una función de estimación. La eficiencia del algoritmo es evidenciado al alcanzar resultados de calidad en instancias de la tardanza total en el problema clásico de Job-shop, como también en instancias del job-shop flexible con otros criterios regulares.

Miel I is a 188 m high RCC dam in Colombia, at elevation 454 m a.s.l. The RCC mix has a cement content of 85 to 160 kg/m3. To meet contractual schedule, the original design of an upstream face made of slip formed reinforced concrete was changed to a Carpi drained exposed composite Polyvinylchloride geomembrane (= PVC geocomposite) system, placed on a 0.4 m thick zone of RCC material enriched with cement grout and vibrated. Placement of the geocomposite system in horizontal stages allowed starting of dam impoundment while RCC placement was still ongoing at higher elevation. The geocomposite system was completed in 2002, before finishing of complementary concrete works. ISAGEN, the owner of the dam, constantly monitors the dam’s and geocomposite system’s performance. The average leakage of the dam registered since the first impoundment of the reservoir has been of 2 l/s for the geocomposite’s drainage system, and of 25 l/s from the abutments. Such levels are below the design parameters that defined the maximum acceptable leakage through the geocomposite in 9.7 l/s and the maximum acceptable leakage through the abutments in 30 l/s. The measured leakage has never surpassed the historical values (with stable lecture through 11 years), or overcome the maximum allowed drainage design values defined during the design stage. After 11 years of good performance and operation, in summer 2013 ISAGEN decided to have a comprehensive monitoring of the general conditions and the weathering behaviour of the waterproofing geocomposite at Miel I. The objectives of the investigation were: assessing the reason of small cuts that had been detected and repaired (in total 15 in 11 years on a 31,000 square meters surface), assessing the conditions of the PVC geocomposite, ascertaining at which extent its characteristics had changed over service, and evaluating if the weathering behaviour was in accordance with the expected durability. Investigation started with inspection at the upstream face and in the drainage galleries, followed by sampling of the exposed PVC geocomposites. Testing in an independent laboratory allowed comparing the physical and chemical properties of the aged geocomposite sample collected at the dam with the physical and chemical properties of the same geocomposite as manufactured. Evaluation of test results, based also on most recent research on geomembrane weathering mechanisms, completed the investigation. Results confirmed that the behaviour of the PVC geocomposite is extremely good and fully in line with expectations. The paper, after a brief outline of the geocomposite system installed at the dam, will describe all steps of the investigation, and detail the test results and the conclusions drawn.

The paper deals with the techno-economical assessment of the gas-cooled/water-cooled fixed-bed reactor network for methanol synthesis. The study is the extension of the first-principles model for the water-cooled reactor already proposed in our prior work (Manenti et al., 2013). Here, the optimization is extended to the steam generation and the reactor length ratio. As a result, basing on the integrated optimization of energy and process yield, we propose to significantly revise the common design. The traditional water/gas-cooling reactor length ratio could be significantly reduced with consequent simultaneous increase in methanol production and steam generation as well, however preserving safety and operational ranges. The economic benefit deriving from the proposed design for a medium-scale process is estimated in more than 1.7 M€/y.

El artículo pretende hacer un reconocimiento a docentes y directivos docentes que han compartido su vida con la comunidad del Colegio Moralba Sur Oriental, pero a la vez conocer los orígenes de la institución partiendo de preguntas orientadoras que fueron plasmadas en el recurso titulado “carta epistolar” lo que permitió activar el recuerdo convirtiéndose en una fuente directa. Toda la información recolectada fue plasmada en una narrativa que es contada a través de tres docentes pensionadas que se adentran en los recuerdos de su experiencia vivida en dicho colegio.

El artículo presenta de manera novedosa la disyuntiva en que la Constitución de 1991 colocó a los grupos indígenas al ofrecer un piso legal para que el Estado impusiera sobre ellos su propia agenda política. A través de la participación directa de las comunidades indígenas en la administración de políticas y recursos estatales, el Estado ha intentado asegurar su hegemonia política entre las comunidades indígenas, las cuales, cada vez con mayor fuerza, reproducen el lenguaje y los mecanismos que el Estado les pone a su disposición para ejercer el "derecho a la diferencia". En este artículo el autor hace un recuento etnográfico sobre los procesos de discusión emprendidos por indígenas muinane de diferentes comunidades del Caquetá medio alrededor de las implicaciones que tiene la creciente penetración delos discursos -'la palabra'- de los 'blancos' en el 'debilitamiento del conocimiento propio' y aporta elementos para una discusión sobre el estatus del conocimiento indígena frente al conocimiento occidental en el contexto del pretendido reconocimiento a la diversidad cultural que se propone la Constitución.