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This study evaluates a binary mixture of fly ash and lime as a stabilizer for natural soils. A comparative analysis was performed on the effect on the bearing capacity of silty, sandy and clayey soils after the addition of lime and ordinary Portland cement as conventional stabilizers, and a non-conventional product of a binary mixture of fly ash and Ca(OH)2 called FLM. Laboratory tests were carried out to evaluate the effect of additions on the bearing capacity of stabilized soils by unconfined compressive strength (UCS). In addition, a mineralogical analysis to validate the presence of cementitious phases due to chemical reactions with FLM was performed. The highest UCS values were found in the soils that required the highest water demand for compaction. Thus, the silty soil added with FLM reached 10 MPa after 28 days of curing, which was in agreement with the analysis of the FLM pastes, where soil moistures higher than 20% showed the best mechanical characteristics. Furthermore, a 120 m long track was built with stabilized soil to evaluate its structural behavior for 10 months. An increase of 200% in the resilient modulus of the FLM-stabilized soils was identified, and a decrease of up to 50% in the roughness index of the FLM, lime (L) and Ordinary Portland Cement (OPC)-stabilized soils compared to the soil without addition, resulting in more functional surfaces.

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The use of industrial solid wastes with a high content of SiO2 and Al2O3, called "precursors", is often studied in the construction industry when combined with NaOH as "activator". The precursor and activator system is generally proposed as a binder material with similar characteristics to Portland cement. In this work, we technically and environmentally evaluated such a system elaborated with an industrial waste: coal ash with caustic soda in solid state. This product, mixed with the soil, acts as a stabilizer to increase the capacity of load support, allowing the improvement of the conditions of performance in low volume traffic roads. An experimental design applied to the stabilizing product showed the incidence of different factors on the load carrying capacity response: packaging material, type of seal, baling moisture and storage humidity. The application of the stabilizer product was found to increase the resistance of the ground over a 500%. Finally, the environmental aspects were evaluated through a simplified Life Cycle Assessment methodology (LCA), the scope of the study was restricted to cradle to gate, collecting data up to the packaged stabilizing product. The results showed that the highest impacts were caused, for most impact categories, by NaOH production, and transport was relevant as well.

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Objetivo: Determinar la relación entre desesperanza, soledad y grado de salud familiar en adolescentes escolarizados, cony sin ideación suicida, para profundizar en el conocimiento del fenómeno desde la disciplina de enfermería y plantear opcionesde promoción y prevención en Bogotá, Colombia. Métodos: Se utilizó el estudio cuantitativo descriptivo correlacional comparativo de corte transversal. La muestra se seleccionó en el período comprendido entre febrero y abril de 2009, a través de un muestreo mixto y estuvo constituida por 482 adolescentes escolarizados entre 14 y 17 años. A través del empleo de análisis estadísticos de tipo univariado, bivariado y multivariado se describió el comportamiento de cada una de las variables, se exploraron las relaciones y contrastes entre éstas y se estimó el efecto de las variables independientes en la presencia de ideación suicida. Se siguieron todas las consideraciones éticas para el desarrollo de investigaciones con seres humanos. Resultados: Entre los adolescentes investigados 20% de la muestra informó presencia de pensamientos o deseos suicidasde variada intensidad. Todas las variables estudiadas influyen la presencia de ideación suicida en los adolescentes a excepción de edad, estrato socioeconómico, localidad y tipo de colegio. Sin embargo a partir de la construcción de modelos de regresión logística se observó que las variables que mejor explican la presencia de ideación suicida son: antecedente de intento desuicidio, baja autoestima, depresión y pertenecer a una familia poco saludable. Conclusiones: Los datos sobre ideación e intento suicida obtenidos en este estudio apoyan la idea de implementar mayores esfuerzos preventivos al interior de las familias y las escuelas. Identificar los adolescentes en riesgo de suicidio o de alteraciones de la salud mental y construir programas efectivos de prevención y programas de tratamiento es una prioridad.

Objective: To determine the relationship between hopelessness, loneliness and the level of family health in school-ageadolescents with and without suicidal ideation to deepen in the knowledge of this phenomenon from a nursing point of view and to pose promotion and prevention options in Bogotá, Colombia.Method: This was a cross-sectional, comparative, correlational, descriptive and quantitative study. The sample wasselected in the period between February and April 2009, through mixed sampling and 482 school-attending 14-17 year-oldadolescents were included. Widely recognized and highly qualified psychometric tools were used to measure the variables concerned. Univariate, bivariate and multivariate statistic analysis were used to describe the behavior of each variable, toexplore the relationships and contrasts between these variables and to estimate the effect of the independent variables on the presence of suicidal thoughts. This study has followed the ethical considerations necessary for research involving human beings. Results: 20% of the sample used reported the presence of suicidal thoughts or desires. All variables studied influence the presence of suicidal thoughts except age, socioeconomic strata, borough and type of school. However, with the use of logistic regression methods, the variables that best express the presenceof suicidal thoughts are: previous suicide attempt, low selfesteem, depression and belonging to an unhealthy family. Conclusions: Data on suicidal ideation and attempts made in this study support the idea of implementing greaterpreventive efforts within families and schools. Identifying adolescents at risk of suicide or mental health disorders, andbuild effective prevention and treatment programs is a priority.

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El benceno, el tolueno y el xileno son solventes orgánicos ampliamente utilizados por la industria. La problemática a escala mundial en relación con la exposición a los hidrocarburos aromáticos se ha centralizado con mayor atención en torno al benceno, el cual se considera peligroso para la salud, aun en concentraciones bajas. El objetivo de este estudio fue determinar la prevalencia de alteraciones en la visión del color en trabajadores expuestos a solventes orgánicos en una empresa de hidrocarburos mediante la aplicación de dos pruebas de la visión del color (Test de Ishihara y Test de Farworth). Se realizó un estudio analítico de corte transversal en 124 trabajadores de los cuales se recolectó información general ocupacional y clínica y se comparó un grupo expuesto con uno no expuesto mediante frecuencias simples, X2, valor p, análisis estratificado. El 3,2 por ciento de los trabajadores presentó alteraciones en la visión del color en el test de Farworth

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