Microwave irradiation provides a way for flash heating as an alternative to standard thermal heating in chemical reactions. This technology has been employed to drastically reduce reaction times and even modify selectivity. In addition to this feature, the use of microwave irradiation may outperform conventional reaction conditions in other aspects, such as easier workup, reduction of the usual thermal degradation products, reduction of toxic and expensive quantities of solvents (green chemistry), and reduction of secondary products. Also, microwave irradiation has proven to be of benefit particularly for reactions under dry media (i.e., in the absence of solvents or solid support) and reactions without catalysts. Our goal is to extend this technology to the academic laboratory and introduce organic chemistry students to microwave-assisted reactions. Thus, we designed an inquiry-based laboratory experience based on the use of a microwave oven as a means for a comparative study of the effect of different catalysts in the synthesis of aspirin. The results, scope and limitations of this study are discussed in the article.

Este libro es el resultado de una iniciativa de investigación conjunta del Banco Interamericano de Desarrollo (BID) y el Programa de las Naciones Unidas para el Desarrollo (PNUD) para mejorar las condiciones de bienestar de la población migrante en América Latina y el Caribe, y contribuir a facilitar su integración en la sociedad a través de la generación de evidencia sobre la entrega de información e influencia en el diseño de políticas públicas. El análisis de los efectos de las intervenciones que se presentan en este libro tiene el potencial de informar el diseño de futuras políticas, con vistas a contribuir a la aceleración de la integración de la población migrante en las comunidades receptoras.

The main contribution of this paper with respect to previous work is the use of data on subjective perceptions to identify the Latin American middle classes. This paper provides a set of comparisons between objective and subjective definitions of middle-class using data from the 2007 W orld Gallup Poll. Seven objective income-based definitions of social class are contrasted with a self-perceived social status measure. Mismatches between the objective and the subjective classification of social class are the largest when the objective definition is based on median incomes. Mismatches result from the fact that self-perceived social status is associated not just with income, but also with personal capabilities, interpersonal relations, financial and material assets, and perceptions of economic insecurity. Objective definitions of the middle class based on absolute incomes provide the lowest mismatches and the most accurate differentiation of the middle class from other classes.

The main contribution of this paper with respect to previous work is the use of data on subjective perceptions to identify the Latin American middle classes. This paper provides a set of comparisons between objective and subjective definitions of middle-class using data from the 2007 W orld Gallup Poll. Seven objective income-based definitions of social class are contrasted with a self-perceived social status measure. Mismatches between the objective and the subjective classification of social class are the largest when the objective definition is based on median incomes. Mismatches result from the fact that self-perceived social status is associated not just with income, but also with personal capabilities, interpersonal relations, financial and material assets, and perceptions of economic insecurity. Objective definitions of the middle class based on absolute incomes provide the lowest mismatches and the most accurate differentiation of the middle class from other classes.