Escuela de Ciencias Geográficas

URI permanente para esta comunidadhttp://10.0.96.45:4000/handle/11056/14684

La Escuela de Ciencias Geográficas (ECG) de la Universidad Nacional, forma profesionales de excelencia, críticos, innovadores, líderes y con alto compromiso ecosocial. Sus áreas sustantivas generan conocimientos estratégicos y científicos, que aportan en la resolución de problemas propios de su objeto de estudio, las relaciones espaciales entre la sociedad, el ambiente, la naturaleza y la tecnología, desde un enfoque multiescalar, multidisciplinario y transdisciplinario.

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Página web: www.geo.una.ac.cr

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Teléfono: (506) 2277-3283

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Analytical and rheological studies of modified gel dosimeters exposed to X-ray beams
(Elsevier Science, 2016-07) Romero, Marcelo Ricardo; Mattea, Facundo; Vedelago, José; Chacón Obando, David M; Valente, Mariana A.; Alvarez, Cecilia; Strumia, Miriam Cristina
The need to know the dose of X-rays to be applied to patients suffering diseases such as cancer requires accurate and stable dosimetric devices. Currently, the use of gelatin-based dosimeters has yielded excellent results but lack adequate thermal stability. In this paper a chemical modification of the gelatin (at concentrations typically used for the preparation of dosimeters) using glutaraldehyde as a cross-linking agent is proposed. Through rheological studies it was found that modified gelatin with glutaraldehyde concentrations between 0.15 and 0.50% w/v shows better thermal stability with an increase in elastic modulus of up to 100 times at 37 °C and convenient reaction times for the preparation of the dosimeters. Subsequently, a mathematical model to easily predict the elastic modulus of materials prepared with different concentrations of gelatin and glutaraldehyde was proposed. The analytical response of modified and unmodified materials was evaluated and no significant alteration of the dosimetric sensitivity was found in the dosimeters (based on itaconic acid and N, N′-methylenebisacrylamide) when an X-ray irradiation dose from 0 to 300 Gy was applied. It was found that the best thermal stability of dosimeters prepared with modified gelatin would decrease the loss of information between the irradiation process and the absorbance reading, thereby improving the stability and linear correlation of data. °C and convenient reaction times for the preparation of the dosimeters. Subsequently, a mathematical model to easily predict the elastic modulus of materials prepared with different concentrations of gelatin and glutaraldehyde was proposed. The analytical response of modified and unmodified materials was evaluated and no significant alteration of the dosimetric sensitivity was found in the dosimeters (based on itaconic acid and N, N′-methylenebisacrylamide) when an X-ray irradiation dose from 0 to 300 Gy was applied. It was found that the best thermal stability of dosimeters prepared with modified gelatin would decrease the loss of information between the irradiation process and the absorbance reading, thereby improving the stability and linear correlation of data. Overall, the results indicated that the dosimeters could be modified as proposed and achieve significant improvements regarding to their thermal stability, without changing significantly the usual preparation process.
La revista electrónica calidad en la educación superior: reflexiones en su cuarto año de funcionamiento (2010-2013)
(Universidad Nacional, Costa Rica., 2013) Alfaro Chavarría, Consuelo; Acón Matamoros, Ariana; Cox Alvarado, Javier
Este artículo corresponde a un análisis de la Revista Electrónica Calidad en la Educación Superior, publicada por el Programa de Autoevaluación Académica, Universidad Estatal a Distancia (UNED) de Costa Rica, en el cual a través de la formación de series y el análisis de unidades de estudio como: autor, año, idioma, entre otras, se pueden obtener datos de gran valor para la evaluación del desempeño y calidad de la revista, en el período comprendido entre 2010-2013. A través de este estudio, se determinó que en este período las ediciones de la revista fueron regulares y con una producción eficiente en cada una de las ediciones estudiadas; en su año más productivo 23 artículos, y llegando a 16 en el año de menor producción, ya que corresponde al año de creación de la revista. Por otra parte, se analizan diversos puntos de interés con el fin de establecer el comportamiento de la revista y las condiciones que se han presentado durante este período.
The geomorphic landscape of the Barva volcano, Costa Rica
(Bellweather Publishing, 2020-03-13) Quesada Román, Adolfo; Mata Cambronero, Erich
Volcanoes have a beneficial role in human development; however, this balance could turn to hazardous processes or even environmental disturbances. Costa Rica is a volcanic country. The people of Costa Rica live upon these landscapes and take advantage of the benefits afforded, such as water recharge, the fertile soils for agriculture purposes, and world-renowned ecological tourism. The Barva volcano is a complex andesitic shield located in the Central Volcanic Range of Costa Rica. Its southern slopes bound the Greater Metropolitan Area (GAM) that contains 65% of the country’s population. We performed a geomorphic landscape analysis which delineated seven landforms that consider the climatic, edaphic, hydrologic, and land use characteristics that describe the largest volcanic massif in Central America. This work is a basic input for environmental, disaster risk, and land use planning for tropical volcanic landscapes under urban and rural pressures. This methodology could facilitate the natural resources management in developing countries where baseline information is scarce.

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