Obtaining value-added products from renewable resources is limited by the lack of specific operating conditions optimized for the physico-chemical characteristics of the biomass and the desired end product. A mathematical model and statistical optimization were developed for the production of volatile fatty acids (VFAs) by anaerobic digestion of municipal sewage sludge. The experimental tests were carried out in triplicate and investigated a wide range of conditions: pH 9.5, 10.5, and 11.5; temperatures 25 °C, 35 °C, 45 °C, and 55 °C; primary sludge with organic loading (OL) of 10 and 14 g VS (volatile solids); and digested sludge with 4 and 6 g VS. Subsequently, a statistical search was performed to obtain optimal production conditions, then a statistical model of VFA production was developed and the optimal conditions were validated at pilot plant scale. The maximum VFA concentration predicted was 6975 mg COD (chemical oxygen demand)/L using primary sludge at 25 °C, initial OL of 14 g VS, and pH 10.5. The obtained third-degree model ( r ² = 0.83) is a powerful tool for bioprocess scale-up, offering a promising avenue for sustainable waste management and biorefinery development.

MSMEs were facing major challenges driven by uncontrollable macro-environmental factors caused by the COVID-19 pandemic. This paper shows the strategies that a sample of Colombian start-ups developed for their survival in the first months of the COVID-19 crisis and the close relationship between these strategies and the aid policies deployed by the Colombian government. This study involved 220 Colombian enterprises from different sectors of the economy (agriculture, commerce, services, and industry) and different stages of the life cycle. Our statistical analysis was based on a deep survey of highly significant rank correlation, the qualitative association between variables, a structural equation model, and mediation analysis. Among our results, we highlight a high dependence on ICT technologies, varied access to economic aid, and strong dependence on negative crisis impacts with the need for aid and deep business changes. Concerning the last conclusion, we found a significant mediating effect of the adaptability of the start-ups in order to explain why older, bigger, and more necessary enterprises were the ones that obtained aid.

Este trabajo es parte de un proyecto en el que estudiantes del semillero de investigación en Ciencia de Datos del Politécnico Grancolombiano fueron entrenados en técnicas de web scraping y modelado de datos de mercados. Los mercados elegidos fueron el de intercambio de divisas (FOREX) y el de acciones de la Bolsa de Valores de Colombia (BVC). Usando programación en lenguaje Python, y una serie de librerías especializadas, los semilleristas lograron la extracción, limpieza y consolidación de datos automática con completa exactitud, sin presentar datos faltantes. Además, los semilleristas lograron desarrollar aplicaciones que permiten el análisis automático con el propósito de recomendar estrategias de trading algorítmico. Esto último está particularmente avanzado en el caso del mercado FOREX, pues ya se ha desarrollado un algoritmo predictivo que promete generar ganancias.