En Ecuador se ha evidenciado que el patrimonio construido con tapia pisada ha presentado un deterioro avanzado debido al paso del tiempo y los factores ambientales, bióticos, intrínsecos y antropológicos. Es importante su preservación y conservación debido a su alto valor cultural e histórico. La presente investigación tiene como objetivo determinar métodos de rehabilitación y reforzamiento aplicables a este tipo de estructuras, orientados a recuperar las características estructurales y mecánicas. Como paso inicial, se llevó a cabo una investigación bibliográfica que permitió determinar la mezcla óptima de tapia pisada, así como los tipos de reforzamientos aplicables, considerando tanto materiales naturales (bambú) como sintéticos (malla de polipropileno). Siguiendo normativas internacionales de ensayos para muros de tierra, se realizaron pruebas que permitieron comprobar la resistencia y efectividad de las técnicas propuestas. Se determinó que el método de reforzamiento mediante el uso de entramado de caña guadua ha permitido la recuperación y el incremento de aproximadamente un 53 % en la resistencia a tracción y un 61 % en la resistencia a compresión.
This study synthesizes peer-reviewed journal articles indexed in the Web of Science Core Collection (2018–2023) to clarify how the water–energy nexus is framed, measured, and governed. We derive nine analytical dimensions from key nexus variables 1) sectoral composition & interactions, 2) resource inputs and outputs, 3) social actors, 4) methodological frameworks, 5) problems and limitations, 6) geographic distribution, 7) operational nexus definitions, 8) territorial scales, and 9) study type. This classification reveals three structural bottlenecks: (i) methodological concentration on static environmentally extended input–output models; (ii) regional aggregation of case studies in data‑rich China, which limits global transferability; and (iii) institutional narrowness, with multi-level governance and civil society underrepresented. Network analysis shows that conceptual framing predicts methodological choice and actor inclusion, and indicates limited methodological diversification —a relationship synthesized into the six pillars proposed below. Beyond existing WEN reviews, this combination of nine-dimension coding, cross-dimensional frequency analysis, and co-occurrence networks provides an empirical basis for the six pillars by linking how the nexus is defined to how it is measured and who is represented in the analysis. To support sustainable engineering decisions, we propose an extended water-energy nexus definition built around six interlocking pillars: high-resolution flow accounting; dynamic feedback modeling (rebound/tipping risks); explicit coupling with carbon, land, and waste; hybrid quantitative–qualitative analytics; inclusive multi-level collaborative governance; and interoperable open-data architectures. Together, these pillars translate fragmented case evidence into an engineering-ready, justice-sensitive systems framework, informing integrated water–energy infrastructure planning, evaluation of energy-transition pathways under water constraints, and prioritization of governance and data-architecture improvements required for interoperable nexus monitoring across sectors and scales.
Ecuador, a country highly dependent on its oil industry, faces the need to import petroleum derivatives due to the lack of a developed petrochemical sector. This study comparatively assesses the technical, economic, and environmental feasibility of three routes for ethylene production, focusing on more sustainable and environmentally friendly processes. The first, the traditional linear process based on thermal cracking of naphtha, is noted for its technological maturity and lower initial costs, but operates under the "extract, produce, dispose" sequence, leading to a high environmental impact due to the substantial energy required and significant greenhouse gas emissions. In contrast, the two proposed circular routes utilize potato agricultural waste as biomass for bio-ethylene production: (a) fermentation to obtain bioethanol followed by catalytic dehydration and (b) electrocatalysis of methane derived from residual biomass. The study's results indicate that while these routes face technical and economic challenges, such as low yields, additional equipment for raw material processing, and higher initial costs, they offer environmental benefits aligned with green chemistry principles, including carbon emission reduction, use of renewable raw materials, and increased energy efficiency. Of the two circular processes analyzed, fermentation is considered the more applicable option due to biomass availability and process maturity in the local industry, despite having a cost 2.6 times higher than the linear process. While naphtha-based ethylene production remains the most viable in economic and technological terms, the development of a sustainable bio-ethylene industry still faces challenges in scalability, yields, and high initial costs but would allow the valorization of agricultural waste, diversifying the country's production matrix and positioning Ecuador as a leader in green innovation in Latin America.
Cocoa bean husks are an abundant waste product that is often discarded despite its valuable bioactive compound content. This study develops a sustainable process, guided by circular engineering principles, to obtain powdered polyphenols through extraction and drying. The study focused on identifying operating conditions that maximize polyphenol recovery, reduce resource consumption, and ensure the stability of the final product. The results show that the proposed process yields a powder rich in polyphenolic compounds with functional properties suitable for integration into cosmetic products. The proposal demonstrates that it is possible to transform agro-industrial waste into a high-value ingredient in line with the demand for sustainable alternatives in the cosmetics industry.
El uso de fibras de acero en el hormigón ha sido ampliamente documentado en diversas obras de ingeniería debido a las ventajas que ofrece en términos de resistencia, control de fisuración y capacidad de absorción de energía. Sin embargo, en Ecuador aún existe un conocimiento limitado entre los profesionales de la construcción sobre sus propiedades y beneficios estructurales. La presente investigación surge de la necesidad de superar las limitaciones inherentes del hormigón convencional, particularmente en su comportamiento post-elástico y en su respuesta frente a la fisuración. Este artículo presenta los resultados de un estudio experimental en el que se diseñaron mezclas de concreto con una resistencia nominal de 24 MPa y se evaluó el comportamiento a flexión de cuatro tipologías de vigas: concreto simple, concreto con adición de fibras de acero, concreto armado convencional y concreto con doble sistema de refuerzo (fibras de acero y varillas). Se ensayaron doce especímenes bajo carga estática, basados en el procedimiento establecido en la norma ASTM C1609. Los resultados evidencian que una adecuada combinación de cemento, agregados y una dosificación de fibras equivalente al 0.56 % en volumen permite incrementar la resistencia última a flexión en un 33.63 % en vigas de concreto simple y en un 12.85 % en vigas de concreto armado. Asimismo, se observa un aumento significativo en la ductilidad, con incrementos del 187.23 % en vigas de concreto simple y del 38.02 % en vigas de concreto reforzado. Los hallazgos demuestran la efectividad de la incorporación de fibras en elementos estructurales sometidos a flexión, evidenciándose mejoras a nivel mecánico y estructural. La presencia de fibras favorece una distribución más uniforme de esfuerzos, reduce las demandas en el refuerzo longitudinal a tracción y permite un aprovechamiento más eficiente de las barras de acero, lo que se traduce en un incremento de la capacidad de carga para secciones equivalentes a las del hormigón armado convencional. Adicionalmente, se confirma una mayor capacidad de absorción de energía y una reducción significativa en el ancho de las grietas.
El estudio tiene como objetivo analizar el desequilibrio en motores de corriente alterna con velocidad variable, específicamente en motores asíncronos, para identificar y controlar los fenómenos de resonancia e inestabilidad que surgen durante la operación a diferentes velocidades. Estos fenómenos pueden provocar vibraciones excesivas, daños en los componentes mecánicos y reducción de la vida útil del motor. Para ello, se realizó un análisis dinámico de un rotor trifásico, utilizando un modelo matemático que considera los coeficientes de rigidez y amortiguamiento de los rodamientos, así como las fuerzas de excitación y las condiciones de lubricación. El rotor se dividió en tres secciones, y se simuló su comportamiento bajo condiciones de desbalance utilizando software de análisis dinámico (Rotor Dynamics Analysis). Además, se realizaron mediciones prácticas de vibraciones con un equipo analizador CSI 2130 para validar los resultados obtenidos en la simulación. Los resultados mostraron la presencia de dos velocidades críticas, una a 800 rpm y otra a 1600 rpm, donde se observaron amplitudes máximas de vibración y condiciones de resonancia. Estas velocidades críticas representan un riesgo significativo para la operación del motor, ya que pueden provocar inestabilidades y daños en los componentes mecánicos. El estudio concluye que es fundamental evitar operar el motor en estas velocidades críticas para prevenir fallos y garantizar su funcionamiento seguro y eficiente. Además, se destaca la importancia de realizar análisis modales y mantenimiento preventivo regular para identificar y mitigar posibles problemas antes de que se conviertan en críticos. Los resultados obtenidos proporcionan información valiosa para optimizar la operación de motores asíncronos en aplicaciones industriales, especialmente en procesos que requieren variación de velocidad, contribuyendo así a mejorar la eficiencia energética y reducir los costos de mantenimiento.
The selection of sleeping perches plays a critical role in predator avoidance, territorial defense, access to feeding areas, and reaching breeding sites. This behavior has been widely studied across various taxa, including the diverse lizard genus Anolis. For Anolis gemmosus, however, only one previous study has addressed sleeping perch selection, focusing solely on physical variables of the perches. In this study, we incorporate additional variables—such as the sex and size of the lizards—and assess their effect on perch type and leaf area. Our results reveal a significant relationship between individual size, particularly in males, and perch area. This pattern may reflect strategies for predator avoidance, or territory maintenance, or may simply result from the higher availability of leaves within a specific range of area in the habitat of A. gemmosus.
Urban slaughterhouses in developing cities often operate in densely populated environments with limited oversight, posing significant occupational health risks. This study investigated the influence of urban planning and proximity factors on disease transmission among workers in slaughterhouses across Aba, Abia State, Nigeria. The aim was to assess how spatial placement, architectural design, and environmental exposures contribute to occupational illnesses. A mixed-methods approach was employed, involving geospatial analysis, environmental monitoring, health surveys (n = 180), and facility inspections across six slaughterhouses (SH-1 to SH-6). GPS mapping revealed that four out of six facilities were within 200 meters of residential or market areas, with SH-1, SH-3, and SH-5 violating basic zoning regulations. Environmental monitoring showed elevated PM2.5 levels ranging from 54–94 µg/m³ (WHO limit: 25 µg/m³), with the highest levels at SH-3 (94 µg/m³). Ammonia (NH₃) and hydrogen sulfide (H₂S) concentrations exceeded safe thresholds in three facilities. Health data showed respiratory symptoms in up to 73% of workers (SH-3) and skin infections in 60% (SH-3). A strong positive correlation was observed between PM2.5 exposure and reported illness, and a significant negative correlation between distance to residential areas and respiratory complaints. Poor infrastructure, weak policy enforcement, and improper zoning were found to exacerbate these health risks. This study concludes that inadequate urban design and poor slaughterhouse placement significantly impacted occupational health. It recommends spatial restructuring, infrastructure upgrades, and integration of health impact assessments into abattoir planning policies in Nigeria.
Ecuador, un país altamente dependiente de su industria petrolera, enfrenta la necesidad de importar derivados del petróleo debido a la falta de un sector petroquímico desarrollado. En este estudio se evalúa comparativamente la viabilidad técnica, económica y ambiental de tres rutas para la producción de etileno, con un enfoque hacia procesos más sostenibles y amigables con el ambiente. La primera, el proceso lineal tradicional basado en el craqueo térmico de nafta, destaca por su madurez tecnológica y menores costos iniciales, pero se basa en la secuencia de “extraer, producir, desechar”, lo que genera un alto impacto ambiental debido a la gran cantidad de energía requerida y las significativas emisiones de gases de efecto invernadero. Por otro lado, las dos rutas circulares propuestas utilizan residuos agrícolas de papa como biomasa para la producción de bioetileno: (a) fermentación para obtener bioetanol seguido de deshidratación catalítica y (b) electrocatálisis del metano derivado de biomasa residual. Los resultados del estudio indican que, a pesar de que estas rutas enfrentan desafíos técnicos y económicos, como bajos rendimientos, más implementación de equipos para tratamiento de materia prima y mayores costos iniciales; ofrecen beneficios ambientales alineados con los principios de la química verde, tales como la reducción de emisiones de carbono, el uso de materias primas renovables y una mayor eficiencia energética. De los dos procesos circulare analizados, la fermentación se considera la opción más aplicable debido a la disponibilidad de biomasa y la madurez del proceso en la industria local, a pesar de tener un costo 2.6 veces mayor que el proceso lineal. Si bien la producción de etileno a partir de nafta sigue siendo la opción más viable en términos económicos y tecnológicos, el desarrollo de una industria de bioetileno sostenible sigue teniendo desafíos de escalabilidad, rendimientos y altos costos iniciales, pero permitiría valorizar los residuos agrícolas diversificando la matriz productiva del país y posicionando al Ecuador como un referente en innovación verde en América Latina.
Este estudio presenta el diseño y la evaluación de un sistema para la detección de la componente electromagnética de las lluvias cósmicas extensas (EAS por sus siglas en inglés) generadas por rayos cósmicos ultraenergéticos. Se propone el uso de antenas log-periódicas y un sistema de radio definida por software (SDR por sus siglas en inglés) para la adquisición y análisis de señales en el rango de 20-80 MHz. Se realizaron simulaciones utilizando ANSYS y pruebas experimentales con un analizador de redes vectoriales, obteniendo coeficientes de reflexión menores a -10 dB. La adquisición de datos se llevó a cabo mediante SDR, con un sistema de disparo automático y filtrado digital. Se recolectaron datos durante 47 días con una frecuencia de muestreo de 1Hz. Los resultados mostraron la detección de señales en el rango de 40-60 MHz, con variabilidad horaria y patrones que sugieren la presencia de eventos asociados a rayos cósmicos. Sin embargo, la validación cruzada con detectores de partículas es necesaria para confirmar estos hallazgos. Este trabajo demuestra la viabilidad de la detección por radio de lluvias cósmicas y plantea la necesidad de integrar estos sistemas con arreglos de detectores de partículas para mejorar la discriminación de eventos.
HIV/AIDS is one of the most important chronic infectious diseases. Although ART therapies decreased morbidity and mortality considerably, new cases continue to appear. HIV-1 drug resistance is one of the most important problems that delay 95-95-95 goals. The presence of drug resistance mutations in naïve and ART-experienced patients is considered a risk factor for treatment failure and the transmission of HIV-1 resistance strains. A cross-sectional study included naïve and ART-experienced patients from one health care center in Quito-Ecuador in 2019 and 2021. Demographic data was collected with blood samples for sequencing, genotyping, and resistance tests. In 42 patients recruited, the overall prevalence of HIV-1 DRM was 9.5%, most related to NNRTI. A total of 42 mutations were found, 38.6% related to PIs, 34.09% to NNRTI/NRTIs, and 22.7% to INSTIs, most of them considered as minor or accessories, producing PLLR, LLR, and in one patient, HLR to NNRTIs. Although few drug resistance mutations that reduce ART susceptibility were identified, further studies are required to characterize HIV-1 drug resistance in Ecuador and its implications for clinical response.
Biopolymers, natural and biodegradable materials, emerge as a promising and sustainable alternative in the oil industry, optimizing oil extraction in a profitable and environmentally friendly way These biopolymers, capable of improving the mobility ratio, increasing viscosity, and decreasing permeability, are emerging as a critical trend in Enhanced Oil Recovery (EOR), with the potential to replace conventional synthetic polymers When selecting polymers for EOR, it is essential to consider factors such as cost, availability, and functional properties The methodology used in the research involved a systematic review of the scientific literature, encompassing a critical analysis of recent advances in biopolymer research for EOR The study also compares biopolymers and synthetic polymers, considering efficiency, cost, and environmental implications Additionally, the research explores the economic considerations associated with utilizing biopolymers in EOR, including cost factors and potential returns on investment Continuous innovation in using biopolymers is seen as the future of EOR, offering a more ecological and responsible alternative to exploit this important resource The choice of biopolymers contributes to a more sustainable and environmentally conscious oil industry.
For the genetic improvement of species of agricultural importance, it is essential to have a broad genetic base, ensuring sufficient variability to increase opportunities for selecting specific traits of interest in the field. Additionally, the use of techniques complementary to conventional breeding systems is crucial for effectively exploring the available genetic variability. Currently, there are several techniques, such as in vitro culture, genetic transformation, gene editing, marker-assisted selection, and mutation induction, among others. This review aims to synthesize the historical development, current applications, and future potential of mutation induction in crop improvement, with an emphasis on its role in adaptation to climate change and food security. Mutation induction techniques have played a key role in addressing challenges related to food security by promoting the development of new varieties for the agricultural sector in various countries. Through the analysis of the FAO/IAEA Mutant Varieties Database, it was possible to identify how mutation induction has contributed to the development of cultivars adapted to the specific needs of food security and climate. The FAO/IAEA program (https://nucleus.iaea.org), which promotes the use of nuclear techniques in agriculture, has resulted in the release of more than 3404 mutant varieties in 233 cultivated species in 75 countries. In several countries, as indicated in the MVD, the use of mutant germplasm in plant breeding programs has been crucial for adapting crops to new climatic conditions, in addition to meeting the growing demand for food. These advances highlight the potential of mutation induction as an essential tool to address future agricultural challenges, underlining the importance of continuing to invest in nuclear techniques for breeding cultivars adapted to climate change and global food security.
Non-Pneumatic Tires, or airless tires, are load-bearing tires that do not require air pressure for that purpose they employ flexible spokes made of thermoplastic Polyurethane. NPTs are characterized by elastic spokes, durability, and resistance to wear, which makes them quite preferable for military, defense, industrial, and space vehicle applications. However, they are somewhat limited in their ability to absorb shocks and comfort, thus limiting their application in commercial vehicles. Hybrid tires provide a solution that unites the merits of NPTs and conventional pneumatic tires. They consist of flexible spokes together with pressurized air, thus giving them properties from both sides-NPTs durability and comfort of a conventional tire. This study is highly focused and presents a comparison of NPTs and hybrid tires. Finite Element Analysis of both models indicates that with respect to strength and comfort, hybrid tires fare very well for civilian vehicles, though their strength may be slightly less than that of NPTs.
To valorize polypropylene (PP) y polystyrene (PS) waste by generating liquid fuels, a pyrolysis process was conducted using a horizontal fixed-bed Shaftherm reactor. Temperature ramps of 500, 600, y 700°C with times of 60, 90, y 120 minutes were used. At temperatures below 500°C, the process was incomplete, yielding only melted polymer. Starting from 500°C, the process was complete, improving with reaction time. For PP, a liquid fraction yield of 56,97% at 500°C y 60 minutes was recovered, increasing to 86,64% at 700°C. For PS, the best yields were obtained at 600°C, with recoveries between 90,36% y 92,63% at 90 minutes. The liquid fractions from PP at 500°C, containing C2-C10 hydrocarbons, resemble commercial extra gasoline C4-C10, while the PS fractions are rich in styrene y C2-C18 chains. Highlighting their high energy potential, PP showed a calorific value between 42 236,64 kJ/kg y 45 005,34 kJ/kg, y PS between 37 401,38 kJ/kg y 43 107,50 kJ/kg. The comparative analysis of the calorific value between the generated liquid fractions y commercial fuels (diésel y gasoline) demonstrated that the obtained products have high potential as energy sources, with PP having a higher calorific value than diésel y extra gasoline. Quality results, such as density y viscosity, were encouraging for industrial applications, y chromatographic analysis revealed the presence of valuable compounds, suggesting their potential use in the chemical industry. Although some parameters did not meet INEN standards, the liquid fractions show significant similarities with commercial fuels, suggesting their viability as an alternative energy source.
For the genetic improvement of species of agricultural importance, it is essential to have a broad genetic base, ensuring sufficient variability to increase opportunities for selecting specific traits of interest in the field. Additionally, the use of techniques complementary to conventional breeding systems is crucial for effectively exploring the available genetic variability. Currently, there are several techniques, such as in vitro culture, genetic transformation, gene editing, marker-assisted selection, and mutation induction, among others. This review aims to synthesize the historical development, current applications, and future potential of mutation induction in crop improvement, with an emphasis on its role in adaptation to climate change and food security. Mutation induction techniques have played a key role in addressing challenges related to food security by promoting the development of new varieties for the agricultural sector in various countries. Through the analysis of the FAO/IAEA Mutant Varieties Database, it was possible to identify how mutation induction has contributed to the development of cultivars adapted to the specific needs of food security and climate. The FAO/IAEA program (https://nucleus.iaea.org), which promotes the use of nuclear techniques in agriculture, has resulted in the release of more than 3404 mutant varieties in 233 cultivated species in 75 countries. In several countries, as indicated in the MVD, the use of mutant germplasm in plant breeding programs has been crucial for adapting crops to new climatic conditions, in addition to meeting the growing demand for food. These advances highlight the potential of mutation induction as an essential tool to address future agricultural challenges, underlining the importance of continuing to invest in nuclear techniques for breeding cultivars adapted to climate change and global food security.
En diciembre de 2019, un brote de neumonía en Wuhan constituiría el epicentro de la pandemia de COVID-19. A pesar de que se identificó un nuevo coronavirus, similar al virus de SARS que produjo una epidemia en 2002, surgieron dos hipótesis sobre su origen: el mercado de animales vivos de Wuhan y la fuga de un virus del Instituto de Virología de Wuhan (IVW). La mayoría de los científicos expertos respalda la hipótesis del origen natural del virus y su propagación a partir del mercado de animales vivos, pero ciertos grupos políticos en Estados Unidos impulsaron la teoría del escape de un virus del Instituto de Virología de Wuhan y debilitaron la confianza en las comunicaciones científicas. Una consecuencia de la desconfianza en la actividad científica fue la oposición a las medidas sanitarias como la vacunación, el uso de mascarillas, el distanciamiento social, junto con el creciente escepticismo de la actividad científica. Estas dinámicas generan consecuencias graves en salud pública y en las posibilidades de vigilancia de futuros virus.
Mining and livestock activities in the Yacuambi canton significantly alter the ecological conditions of aquatic bodies, particularly rivers and water sources used for human consumption. This study evaluated water quality using methods based on bioindicators, specifically phytoplankton, as a complementary approach to physicochemical assessments. Phytoplankton play a crucial role in the structure and primary production of aquatic ecosystems; therefore, analyzing their composition and structure serves as a biological indicator of water quality. In situ water samples were collected for both physicochemical analysis (pH, dissolved oxygen, conductivity, total dissolved solids, temperature, nitrates, and phosphates) and biological analysis (diatoms). In the laboratory, microscopy and quantification of phytoplanktonic cells were conducted, enabling the application of an index to determine water quality. The application of the General Diatom Index (GDI) revealed significant differences in water quality (p < 0.05) among the Santa Inés stream and the Yacuambi and El Salado rivers. In terms of abundance, individuals from the genera Microspora, Ulothrix, Navicula, Gomphonema, and Ulnaria were recorded. Temperature, dissolved oxygen, and conductivity were the variables that most differentiated the studied rivers (p < 0.05). Multivariate analysis revealed the formation of specific groups for each river, including phytoplankton organisms that serve as indicators of water quality and physicochemical variables, which together explained at least 69 % of the data variability in all cases.
The Galápagos hawk Buteo galapagoensis is the top predator of the archipelago, feeding on a wide variety of species from different taxonomic groups, ranging from insects to carrion. We report the first recorded instance of predation by a Galápagos hawk on a feral cat Felis catus, as camera trap bycatch, on Wolf Volcano, Isabela Island. This report adds to the extensive list of the hawk’s dietary items and may have ecological implications, such as the role of introduced species in food webs, the role of native predators in controlling invasive species, and how these interactions play out on islands, leaving many open questions.
