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La necesidad de energía de la población ha originado con el paso de los años problemas de contaminación ambiental asociados al uso de combustibles de origen fósil. La bioenergía es una alternativa que diversos países han propuesto para disminuir el volumen de gases contaminantes a la atmósfera; el biodiésel y bioetanol son los que presentan mayores ventajas comerciales en el mundo, aparte de que son necesarios para el cumplimiento de acuerdos internacionales en materia ambiental. El presente trabajo se enfoca en analizar la ventaja comparativa en 56 países respecto a la producción de biodiésel y bioetanol, para lo cual se utilizó el índice de la ventaja comparativa revelada (VCR) y el índice de la ventaja comparativa revelada normalizada (VCRN). Los resultados muestran que para la producción de biodiésel los países con mayor ventaja son España, Argentina, Brasil, Indonesia y la Unión Europea (conjunto de 28 países), mientras que en la producción de bioetanol sobresalen Colombia, Estados Unidos, Argentina, Brasil y la Unión Europea. Códigos JEL: Q24, E23 Recibido: 29/12/2021. Aceptado: 21/07/2022. Publicado: 01/12/2022.

Geoparks are unique geographical areas whose geological significance is worthy of UNESCO designation as a Global Geopark. As of 2022, 177 geoparks located in 46 countries have this designation. The aim of this paper is to identify and analyse the worldwide scientific production published in the Web of Sciences database in the context of Geoparks. The methodology used was bibliometric analysis, which allows for the rigorous exploration and analysis of large volumes of data. To this end, descriptive and relational indicators were obtained for the field of study; performance analysis, scientific mapping, and network analysis. A total of 324 articles were identified, the first of which was from 1999 by Wolfgang Eder, in which he presented the UNESCO initiative on the creation of geoparks as a tool to promote a better understanding of the geological heritage and the rational use of the Earth’s crust; the rest of the articles were written after the programme was launched (2001). Few authors work on the subject continuously, the author with the highest number of publications has six, and most of the authors with a single authorship are transient. The countries with the highest number of publications are China, followed by Spain, Portugal, Brazil and Italy, where scientific production is concentrated; the high rate of transience indicates that many countries have only one publication. Most publications are concentrated in two journals: geoheritage and geosciences. In the early years (1999–2003), publications were associated with two research areas, geology and palaeontology, and it is in the last five years (2019–2002) that the areas of knowledge showing interest in the subject have diversified.

Red beets in Mexico are used in the colorants industry, but their juice bagasse (RBB) can be carbohydrates for ethanol production. The present study aims to the pretreatment of bagasse of red beet using acid (H2SO4) and alkali (NaOH) to improve the availability of sugars. Also, describe quantitatively in the hydrolysates the microbial growth, substrate consumption, and ethanol production with simulation using data kinetics of red beet and logistic, Pirt, and Luedeking-Piret equations. Experiments with H2SO4 at sterilization conditions resulted in lower phenolic formation and increased hydrolysis to 32 %. Logistic, Pirt, and Luedeking-Piret equations were used to quantitatively describe the hydrolysates the microbial growth, substrate consumption, and ethanol production, respectively. In the alkali treatment, a significant mean difference was found (p < 0.05) in substrate mass and reaction time. The maximum yield of 38 g/L of total sugars at 72 h of reaction was obtained from 6 g RBB and H2SO4 at 0.5 N. The ethanol yield was 15 to 18 g/L representing about 78 to 92 % of the theoretical yield.

In this work the effects of pH and temperature on ethanol production from red beet juice by the strains Saccharomyces cerevisiae ITD00196 and S. cerevisiae ATCC 9763 are studied. Logistic, Pirt, and Luedeking-Piret equations were used to describe quantitatively the microbial growth, substrate consumption, and ethanol production, respectively. The two S. cerevisiae strains used in this study were able to produce ethanol with high yield and volumetric productivity under acid and thermal stress conditions. The equations used to model the fermentation kinetics fit very well with the experimental data, thus establishing that ethanol production was growth associated under the evaluated conditions. The yeast S. cerevisiae ITD00196 had the best fermentative capacity and could be considered as an interesting option to develop bioprocesses for ethanol production.

The objective of this work is to determine the control structure that avoids the concentration drop due to the nonlinear effect of the binary azeotrope present in the distillation process of the azeotropic ethanol-water mixture, for this purpose a Smith predictive control structure is applied, which is compared with the behavior of a system with delay and an integral proportional control. This applied to a previously characterized experimental plant, for the simulation, the analysis of the step response of each of the proposed systems is performed, confirming that the predictor eliminates the overshoot in the behavior of the system during the distillation while the implemented PI control maintains them even when the response speed of it is lower. [ABSTRACT FROM AUTHOR]

Introducción: la desigualdad laboral que viven hombres y mujeres se hace evidente en los ingresos. El objetivo del presente trabajo fue analizar los ingresos económicos de mujeres y hombres en las actividades económicas en México durante los últimos 15 años, a partir de la descomposición Oaxaca-Blinder, con el propósito de detectar las brechas salariales por género. Método: para llevar a cabo el análisis, se consideraron los 20 sectores de actividad contemplados en el Sistema de Clasificación Industrial de América del Norte. Se extrajo información de la Encuesta Nacional de Ocupación y Empleo acerca del sexo, los ingresos por hora, los años de escolaridad y la edad de los individuos. Se aplicó la ecuación básica de descomposición Oaxaca-Blinder posterior a la realización de análisis econométricos mediante regresiones lineales múltiples, a través de la ecuación de salarios de Mincer. Resultados: los resultados del análisis presentan una brecha salarial en las actividades económicas de, por un lado, a) construcción, y b) transporte, comercio y almacenamiento, favorable a las mujeres en cada uno de los años del análisis. Por otro lado, en las actividades c) corporativos, y d) otros servicios, excepto actividades gubernamentales, se aprecia una brecha salarial favorable a los hombres en todos los años del estudio. Discusión o conclusión: los ingresos económicos han permitido mostrar la diferencia salarial entre hombres y mujeres en las distintas actividades económicas de México, favorable en algunas actividades a las mujeres, aunque en la mayoría es favorable a los hombres.