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Island electricity generation systems (IES) pose challenges in the integration of renewable energies that are compatible with security of supply. This work proposes a methodology and a proposed decision tool that allows the optimization of the production of different generation systems, both renewable and non-renewable, setting a series of objectives such as the reduction of greenhouse gases (GHG), production costs and at the same time fulfilling the best coverage in dynamic response, security, scalability, and integration. This tool is based on operational research, mathematical optimization methods, specifically the simplex algorithm and the generalized reduced gradient (GRG) and proposes different combinations to achieve an energy production that meets the demand, minimizing fuel consumption and greenhouse gas (GHG) emissions.

El objetivo de este estudio es mostrar el sentir de los estudiantes de licenciatura durante la contingencia sanitaria. Se realizó un estudio cualitativo a través de la narrativa de 35 estudiantes. Los principales resultados muestran que éstos se enfrentaron a diversos sentimientos y retos en su aprendizaje a lo largo de casi dos años de confinamiento.

The Canary Archipelago, in general, and the island of Gran Canaria, in particular, operate with an independent energy system (SIE), which depends largely on local power generation. Today, its energy supply comes mainly from two sources: (a) Renewable energy, accounting for 19.90%, and (b) Fossil fuel combustion in thermal power plants, contributing the remaining 80.10%. The existing energy infrastructure faces challenges due to aging technology, requiring either modernization or replacement to prevent a potential energy crisis and ensure a sustainable production cycle. A transformative step to improve the system is the completion and commissioning in 2030 of the Chira-Soria pumped hydroelectric energy storage (PHES) plant. This installation will allow water to be transported to high altitudes by pumping, to be deposited until the right time and to be turbined to generate electricity in optimal conditions. To fully understand the impact of this integration, detailed analyses of annual energy production patterns, equipment performance, and real-time demand data (collected at five-minute intervals) will be conducted. These assessments will provide insights into how the Chira-Soria PHES can be seamlessly integrated into Gran Canaria's energy network. Furthermore, they will help identify both the strengths and limitations of this storage solution, paving the way for a more resilient and efficient energy future for the island. [ABSTRACT FROM AUTHOR]

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A partir de la creación del Servicio Profesional Docente (SPD) en 2013, a la evaluación que se aplica a los docentes de educación básica y media superior se le agregaron tres momentos laborales más que se refieren al ingreso, la permanencia y la promoción de los docentes y directivos, en este sentido, el objetivo de este documento es presentar avances en la sistematización de los resultados obtenidos por los docentes de educación media superior a través de las diversas evaluaciones realizadas por la instancia mencionada; lo anterior, a partir de la revisión documental de diversas fuentes para el tratamiento de la información y su valoración. Los resultados encontrados refieren que la profesionalización docente en los tres espacios laborales en que se lleva a cabo presenta serias limitaciones en lo logrado, considerando las diferentes evaluaciones; con ello es posible determinar que los resultados de estas evaluaciones no han logrado establecer indicadores que aseguren que la mejora de la calidad educativa, ofrecida en la educación media superior en México, sea posible en los términos señalados por la política educativa vigente debido a que los docentes no han superado los indicadores solicitados por el SPD.

The integrated production of biofuels from agro-industrial wastes is increasing around the world. The thermodynamic performance and economic analysis of these processes have become topics of interest given the need to reduce the cost of biofuels and their impact on the environment. This study develops a simulation of the production process of syngas and biodiesel from spent coffee grounds, and an exergoeconomic analysis that mainly determines the exergy destruction rate, the investment and operational cost rate, and the exergy destruction cost rate at component level and for the overall system. The total investment cost for the integrated process resulted in 13.2 million dollars. The specific cost of syngas and biodiesel from spent coffee grounds were estimated in $0.36/kg and $0.71/kg, respectively. The results show that the drying process including the air heating for the pretreatment of the biomass had an exergy destruction rate of 11,463 kW and was responsible of the 92% of the overall exergy destruction cost rate. An increment of the dead state temperature reduced the specific cost of syngas and biodiesel in 17% and 8%, respectively. Future studies should focus on the exergoeconomic optimization of the drying process of biomass in order to minimize the operational costs.

Biofuels have become a source of renewable energy to offset the use of fossil fuels and meet the demand for electricity, heat, and cooling in the industrial sector. This study aims to (a) develop a simulation of a trigeneration system based on a gas turbine cycle and an absorption chiller unit, using biomass and syngas from spent coffee grounds (SCGs) to replace the conventional system currently supplying the energy requirements of an instant coffee plant located in Guayaquil, Ecuador, and (b) carry out an exergoeconomic analysis of the simulated system to compare the effects of different fuels. The results showed an increase in the exergetic efficiency from 51.9% to 84.5% when using a trigeneration system based on biomass instead of the conventional non-integrated system. Furthermore, the biomass-based system was found to have the lowest operating costs ($154.7/h) and the lowest heating, cooling, and power costs ($10.3/GJ, $20.2/GJ, and $23.4/GJ, respectively). Therefore, the results of this analysis reveal that using SCGs as biofuel in this instant coffee plant is feasible for producing steam, chilled water, and power.

Ante la diversificación de la educación media superior, la población estudiantil que accede a la educación superior presenta características sociales, académicas y culturales, que ponen nuevos retos a las instituciones de este nivel educativo para atenderla. Este artículo presenta una experiencia de las características de los estudiantes de licenciatura de la Universidad Pedagógica Nacional. Unidad- Ajusco (ciclo escolar 2015-2016).

Por primera vez en el estudio del fenómeno megalítico del sureste de la Península Ibérica se ha obtenido una serie radiocarbónica para el análisis de sus manifestaciones más antiguas. Se han datado 30 restos antropológicos de sepulturas tipo rundgräber y de tumbas de cámara y corredor pertenecientes a las necrópolis de Las Churuletas, La Atalaya y Llano de El Jautón. El análisis estadístico de esta serie radiocarbónica ha permitido establecer las siguientes conclusiones: i) el inicio de la actividad funeraria ocurriría entre el 3730-3650 cal BC y el final entre el 2395-2270 cal BC; ii) las sepulturas tipo rundgräber son las que poseen una duración más corta, finalizando entre el 2650-2505 cal BC; III) la datación de diferentes sepulturas y necrópolis muestra una importante heterogeneidad en sus periodos de uso; y iv) a partir de principios del III milenio se produciría una significativa intensificación de la actividad funeraria paralela al incremento demográfico y desarrollo del poblamiento.

A partir de implementar la profesionalización docente en el marco de la reforma educativa hacia los profesores de Educación Media Superior, las instancias gubernamentales entre otros, establecen una formación docente que presenta una visión hegemónica, reconfigurando la figura y la práctica docente sin considerar las particularidades y las necesidades específicas de formación que subyacen en este nivel educativo.

Este trabajo describe la aplicación del Índice de Calidad del Agua del Concilio Canadiense de Ministerios del Medioambiente (CCMEWQI) para cuatro estaciones situadas en el río Luyanó, La Habana, Cuba. El río fue evaluado desde diciembre del 2010 hasta noviembre del 2017. El CCMEWQI fue aplicado a seis parámetros de calidad de agua (pH, oxígeno disuelto, demanda bioquímica de oxígeno, demanda química de oxígeno, coliformes totales y coliformes fecales). El índice tuvo un valor de 14, que indica que el río tiene una pobre calidad debido al efecto de diversas fuentes de contaminación. Palabras clave: contaminación, índice de calidad del agua CCMEWQI, río Luyanó.

The pumped hydropower energy storage (PHES) assessments carried out so far have been focused on large water bodies obtained from global or restricted-use databases, or, on the other hand, on the application of methodologies to specific areas focusing on the detection of dams. In addition, many assessments do not include data optimization, or include it at the end of the process and are subject to the prior application of restrictions, often stipulated with subjective criteria. The aim of this article is to design a universal and easily applicable methodology for the assessment of viable PHES potential, which provides immediate and reliable results to assist in the energy planning of a given territory. It is classified in ravine basins, including an optimization before using the restrictions. The island of Gran Canaria is taken as the territory of application, whose density of dams is the highest in the world and whose share of hydroelectric energy is, at present, null; besides, no PHES studies have been carried out. The results show that the PHES potential in Gran Canaria is 5996 MWh after applying the optimization and all technical constraints. If all environmental constraints were rigorously applied, the island would have no possible pairing. The results demonstrate the importance of tailoring the restrictions to each particular territory.

The time spans of the so-called ditched enclosures are key to a better understanding of a type of site characterised by complex palimpsests. Several conclusions can be drawn from the 16 radiocarbon dates obtained from Ditch 4 at Marroquíes Bajos. According to Bayesian modelling, the filling process began in 2510-2310 cal BC at 2 σ and ended in 2115-1795 cal BC at 2 σ, making them the most recent ditched enclosure with depositional activity in Iberia. Comparison with the dating from other sections of Ditch 4 challenges the traditional assumption that radiocarbon samples obtained from deposits at the bottom of the ditch provide the best dates for its construction. The process by which different sections of the same Ditch 4 were filled at different times suggests that its general outline is more the result of an aggregation of segments than of a single build-up.

Instant coffee is produced worldwide by spray drying coffee extract on an industrial scale. This production process is energy intensive, 70% of the operational costs are due to energy requirements. This study aims to identify the potential for energy and cost improvements by performing a conventional and advanced exergy and exergoeconomic analysis to an industrial-scale spray drying process for the production of instant coffee, using actual operational data. The study analyzed the steam generation unit, the air and coffee extract preheater, the drying section, and the final post treatment process. The performance parameters such as exergetic efficiency, exergoeconomic factor, and avoidable investment cost rate for each individual component were determined. The overall energy and exergy efficiencies of the spray drying system are 67.6% and 30.6%, respectively. The highest rate of exergy destruction is located in the boiler, which amounts to 543 kW. However, the advanced exergoeconomic analysis shows that the highest exergy destruction cost rates are located in the spray dryer and the air heat exchanger (106.9 $/h and 60.5 $/h, respectively), of which 47.7% and 3.8%, respectively, are avoidable. Accordingly, any process improvement should focus on the exergoeconomic optimization of the spray dryer.

Conocer el grado de satisfacción de los usuarios en relación con los servicios de salud resulta importante, especialmente para aquellas instituciones de salud que decidieron implementar el Sistema Único de Acréditación, que las destaca como las de mejor calidad en la prestación de servicios y que deben, por tanto, verificar el impacto que ejercen sobre la satisfacción del cliente. Evaluar la satisfacción de los usuarios es un proceso complejo, entre otras razones por la alta subjetividad que presenta. El objetivo de esta investigación es identificar el nivel de satisfacción y la percepción de los cambios generados con la adopción del Sistema Único de Acreditación, en los usuarios externos del Centro Policlínico del Olaya de Bogotá - CPO. El proceso metodológico seguido permitió obtener información del Policlínico sobre el estado previo a la implementación del Sistema de Acreditación y el posterior a este, en materia de satisfacción de usuarios. Igualmente se plantea el diseño y aplicación de una herramienta que permita identificar el grado de conocimiento que los usuarios de este Centro tienen sobre el Sistema en mención. Los resultados muestran el esfuerzo que el Centro Policlínico ha realizado mediante un trabajo constante y continuo en materia de calidad, así como las apreciaciones que los usuarios tienen sobre el Centro y sobre el Sistema Único de Acreditación en Salud.