Universidad de las Fuerzas Armadas-ESPE

This research explores the spatial and temporal variations of nitrogen dioxide (NO₂), sulphur dioxide (SO₂), and ozone (O₃) levels in four Latin American cities, namely Mexico City, Santiago de Chile, Lima, and the Metropolitan District of Quito, utilizing Sentinel-5P satellite data alongside ground-based monitoring stations. The period covers pre-lockdown, lockdown, and post-lockdown phases of the COVID-19 pandemic, providing insights into pollutant behaviour across different levels of human activity. Findings show notable spatial variability in pollutant levels, with Santiago de Chile repeatedly presenting the highest concentrations of NO₂ and SO₂, linked to urban development and local weather patterns, whereas Quito showed the lowest levels. The lockdowns typically resulted in decreased NO₂ concentrations, yet their effects on SO₂ and O₃ levels were inconsistent, highlighting the complexity of pollutant interactions. The research confirms that satellite data serves as an affordable addition to conventional monitoring, especially in areas with limited resources. These results emphasize the necessity for customized, city-oriented strategies to reduce urban air pollution and safeguard public health.

Identifying the main species of plants from where Ecuadorian stingless bees collect pollen is one of the key objectives of management and conservation improvement for these insects. This study aims to determine the botanical origin of pot-pollen using two barcodes, comparing two methodologies (DNA barcoding versus electron microscopy and morphometric tools) and determine the genus and species of pollen source plants of the main honey-producing stingless bees in Ecuador. As main results, Prockia crucis, Coffea canephora, Miconia nervosa, Miconia notabilis, Laurus nobilis, Cecropia ficifolia, Theobroma sp., Artocarpus sp., Croton sp., Euphorbia sp., Mikania sp., and Ophryosporus sp., were the genera and species with the highest presence in the nests (n = 35) of three genera of stingless bees of two provinces located in different climatic regions inside the continental Ecuador. Plant species richness in both areas was statistically similar (p-value = 0.21). We concluded that floral sources’ molecular identification with the ITS2 region had a higher number of genera and species detected, than the rbcL gene and microscopy tools, for the Ecuadorian landscapes. We confirmed that the foraging behavior of Melipona sp., Scaptotrigona sp., and Tetragonisca sp., could include non-native flora (27%, 12/44 identifications) that provide a rich source of pollen. Stingless beekeepers could use this information to create flower calendars and establish a schedule for better management of stingless bees in secondary and modified environments.

This investigation examines the dynamic response of an accelerating turbulent pipe flow using direct numerical simulation data sets. A low/high-pass Fourier filter is used to investigate the contribution and time dependence of the large-scale motions (LSM) and the small-scale motions (SSM) into the transient Reynolds shear stress. Additionally, it analyses how the LSM and SSM influence the mean wall shear stress using the Fukagata-Iwamoto-Kasagi identity. The results reveal that turbulence is frozen during the early flow excursion. During the pretransition stage, energy growth of the LSM and a subtle decay in the SSM is observed, suggesting a laminarescent trend of SSM. The transition period exhibits rapid energy growth in the SSM energy spectrum at the near-wall region, implying a shift in the dominant contribution from LSM to SSM to the frictional drag. The core-relaxation stage shows a quasisteady behaviour in large-and small-scale turbulence at the near-wall region and progressive growth of small-and large-scale turbulence within the wake region. The wall-normal gradient of the Reynolds shear stress premultiplied energy cospectra was analysed to understand how LSM and SSM influence the mean momentum balance across the different transient stages. A relevant observation is the creation of a momentum sink produced at the buffer region in large-and very large-scale (VLSM) wavelengths during the pretransition. This sink region annihilates a momentum source located in the VLSM spectrum and at the onset of the logarithmic region of the net-force spectra. This region is a source term in steady wall-bounded turbulence.

We assessed combined, low-cost physical–chemical and biological treatment system for the remediation of acid rock drainage (ARD). Two columns composed of native soil amended with zero valent iron and iron sulfide (ZVI/FeS) nanoparticles-based Technosols were connected to a sulfate-reducing (SR) bioreactor; this integrated treatment system was fed with ARD obtained from mines in El Oro, Ecuador. A control sulfate-reducing bioreactor fed directly with ARD was run in parallel. The bioreactors were operated dynamically for four periods, and every 21 days, the fraction of ARD in the influent was increased stepwise from 25 to 100%. The integrated treatment system demonstrated superior removal efficiencies for Fe (99%), As (99.9%), Cd (99%), Cu (98%), Mn (91%), and Zn (99.9%), while both bioreactors achieved similar sulfate reduction (50–52%) and raised ARD pH from 2.75 to ~ 8. However, the ZVI/FeS nanoparticles-based Technosols significantly improved the removal of As (99.9% vs. 68%) and Mn (91% vs. 71%), compared to the control bioreactor. Molecular ecology analysis of the biomass in the bioreactors using 16S rRNA sequencing revealed that higher ARD concentrations enhanced sulfidogenesis, promoting beneficial interactions within communities in the sulfate-reducing niche. This study highlights the value of the ZVI/FeS nanoparticles-based Technosols in optimizing ARD bioremediation, offering a promising solution for mining effluent management in low-middle-income countries (LMIC). Graphical Abstract Performance of an integrated system composed of native soil amended with ZVI/FeS nanoparticles-based Technosols and a bioreactor for the treatment of acid rock drainage. Created in BioRender.com 02/10/2024

Comprehensive and integral treatment of agricultural wastes is crucial to palliate the environmental impact associated with uncontrolled disposal. However, waste management should be focused on a local perspective. In this study, the anaerobic co-digestion of four lignocellulosic by-products generated in Ecuador (cocoa husks, coconut shells, rice hulls, and sugarcane bagasse) was evaluated. Two different mixture ratios, the impact of thermal pretreatment, and the influence of the inoculum origin were also assessed. Results showed that the anaerobic inoculum collected from a brewery factory showed the highest efficiency. Moreover, thermal pretreatment improved the methane yields (158–160 NLCH4 kg⁻¹VS). However, the highest kinetic constant (1.1 ± 0.1 d⁻¹; first-order kinetic model) and the maximum methane production rate (153 ± 3 NLCH4 kg⁻¹VS d⁻¹; logistic model) were obtained for the untreated mixtures. Finally, the substrate mixture ratio did not influence the anaerobic digestion performance. Therefore, the present study provides preliminary insights into the viability of anaerobic co-digestion as a feasible technology for the valorization of agro-industrial lignocellulosic residues to reduce the effect of seasonal production variations.

The COVID-19 pandemic underscored the critical need to enhance screening capabilities and streamline diagnosis. Point-of-care (POC) tests offer a promising solution by decentralizing testing. We aimed to validate the PLUM device (LSK Technologies Inc.), a portable optical reader, to detect SARS-CoV-2 RNA using direct RT-LAMP targeting the ORF1a and E1 genes and patient antibodies by ELISA. The direct RT-LAMP assays employ nasopharyngeal swabs and bypass RNA extraction protocols through a brief chemical and physical lysis step. Test sensitivity and specificity were assessed against gold-standard detection methods in laboratory and field conditions. For samples with Ct values below 25, direct RT-LAMP showed 83% sensitivity and 90% specificity under laboratory conditions and 91% sensitivity and 92% specificity under field conditions. The nucleocapsid antigen antibody assay had 99% positive percent agreement (PPA) and 97% negative percent agreement (NPA), outperforming spike-RBD antigen (98% PPA, 92% NPA) and seroprevalence (98% PPA, 88% NPA) under laboratory conditions. Under field conditions, similar results were found for antibody detection for the nucleocapsid antigen (93% PPA; 100% NPA), spike-RBD (100% PPA; 94% NPA), and seroprevalence (90% PPA; 94% NPA). This study validated the PLUM device as a dual POC tool for direct RT-LAMP-based SARS-CoV-2 and ELISA-based COVID-19 antibody detection.

The suspension system in plays a pivotal role, especially in off-road vehicles, in ensuring optimal comfort, road holding and ride safety. This study explores the transition from a MacPherson strut to a double wishbone suspension system, emphasizing its impact on relevant suspension features, such as camber and caster angles, motion ratio and vertical dynamics. Through this study, an off-road vehicle was retrofitted with the proposed suspension architecture and tested both numerically and experimentally. Test results reproduce simulation outcomes, thus confirming the effectiveness of the redesigned suspension system for the target vehicle, especially for demanding off-road applications.

Protected areas play a crucial role in biodiversity conservation worldwide, but often neglect the involvement of local communities. This study presents a participatory planning methodology for promoting social and economic development in protected areas, using Cotopaxi National Park (PNC) in Ecuador as a case study. The PNC represents an appropriate case study due to its diverse ecosystems and challenges related to grazing activities. The proposed methodology integrates a qualitative approach with the Social Network Analysis (SNA) and the Analytic Network Process (ANP) to design a sustainable management approach. Firstly, the SNA maps the stakeholder network, identifying key actors and their relationships. Secondly, interviews with influential stakeholders provide insights into their perceptions of influence, relationships, and strategies to enhance grazing activities. Thirdly, the ANP is used to analyze and prioritize management strategies. Finally, a novel sensitivity analysis was made to validate the results. The promotion of new opportunities for productive projects and alternative sources of income was the best-rated strategy for sustainable grazing. The proposed methodology can facilitate and improve the co-management of the protected areas and their governance. It allows the integration of environmental conservation objectives with the main concerns of the stakeholders, promoting social and economic development. This study confirms that stakeholders have different interests, sensitivities, and ways of understanding sustainability; thus, improving stakeholder communication and the involvement of additional actors, such as NGOs and government agencies, is crucial. The proposed integrated approach can be adapted to any participatory decision-making process related to the conservation of protected natural areas.

Hybrid photovoltaic (PV) and thermoelectric generator (TEG) systems combine heat and light energy harvesting in a single module by utilizing the entire solar spectrum. This work analyzed the feasibility and performance of a hybrid photovoltaic–thermoelectric generator system with efficient thermal management by integrating heat pipe (HP), radiative cooling (RC), and heat sink (HS) systems. The proposed system effectively reduces the PV operation temperature by evacuating the residual heat used in the TEG system to generate an additional amount of electricity. The remaining heat is evacuated from the TEG’s cold side to the atmosphere using RC and HS systems. This study also analyzed the inclusion of two TEG arrays on both sides of the HP condenser section. This numerical analysis was performed using COMSOL Multiphysics 5.5 software and was validated by previous analysis. The performance was evaluated through an energy and exergy analysis of the TEG and PV systems. Enhancing the thermal management of the hybrid PV-TEG system can increase energy production by 2.4% compared to a PV system operating under the same ambient and solar radiation conditions. Furthermore, if the proposed system includes a second array of TEG modules, the energy production increases by 5.8% compared to the PV system. The exergy analysis shows that the enhancement in the thermal management of the PV operating temperature decreases the thermal exergy efficiency of the proposed system but increases the electricity exergy efficiency. Including TEG modules on both sides of the condenser section of the HP shows the system’s best thermal and electrical performance. These results may be helpful for the optimal design of realistic solar-driven hybrid systems for globally deserted locations.

This study presents a novel fifth-order iterative method for solving nonlinear systems derived from a modified combination of Jarratt and Newton schemes, incorporating a frozen derivative of the Jacobian. The method is applied to approximate solutions of the nonlinear convection–diffusion equation. A MATLAB script function was developed to implement the approach in two stages: first, discretizing the equation using the Crank–Nicolson Method, and second, solving the resulting nonlinear systems using Newton’s iterative method enhanced by a three-step Jarratt variant. A comprehensive analysis of the results highlights the method’s convergence and accuracy, comparing the numerical solution with the exact solution derived from linear parabolic partial differential transformations. This innovative fifth-order method provides an efficient numerical solution to the nonlinear convection–diffusion equation, addressing the problem through a systematic methodology that combines discretization and nonlinear equation solving. The study underscores the importance of advanced numerical techniques in tackling complex problems in physics and mathematics.

Landslides in the Northern Andes of Ecuador appear frequently due to the geological conditions of the area, like the strong movement that occurred on February 12, 2021 in the Chunchi canton. This landslide event has been one of the largest in the region, as it covered an approximate area of 115.35 ha, based on a combination of movements. The present investigation focuses on two main objectives, of which the first consisted of evaluating the main landslide characteristics together with the lithological identification of the affected area using non-destructive tests and by collecting samples that were subsequently tested in the laboratory. The second objective aims to identify the main triggering factors through the analysis of the given precipitation in the period of 2016–2021 and the analysis of pre-event earthquakes near the study area. We were able to establish that the movement was rotational, crawling and flow, classifying the soil as a type D profile, which is considered rigid. Furthermore, we encountered degraded surface material, being identified as materials of volcanic and volcano-sedimentary origin within the matrix. On the surface of the landslide, silty sand, clayey sand and volcanic ash deposits were observed between 1 and 2 m of depth. It was also determined that the soils were saturated from a depth of 3.92 m as a result of severe rainfall and agricultural activities, generating an increase in the hydrostatic load and therefore in the pore pressure, which resulted to be the main trigger of this catastrophic event.

Stingless bees are crucial for pollination and support diverse ecological relationships, offering economic benefits and contributing to enhanced crop yields. Their tropical pollinator status makes them highly sensitive to environmental changes and disruptions, which could affect their survival, as well as to pathogens that threaten their health. The lack of comprehensive research and the scattering of reports make it difficult to identify pathogens and contaminants. This review aims to provide an overview of diseases in stingless bees, examine chemical contaminants in their products, and explore threatened sources. Using the PRISMA flowchart, a total of 30 articles from 2009 to 2024 concerning pathogens and contaminants in stingless bees were retrieved. A total of 15 pathogens and 26 pollutants affect life expectancy and survival rate of stingless bees (mainly the genera Melipona and Tetragonisca) were identified in five major areas of the Neotropics, including Brazil, Mexico, Costa Rica, Australia, and Asia. Studies indicated that the bacterial genera Pseudomonas, Melissococcus, and Lysinibacillus are affecting the survival of stingless bees, particularly their brood, and contributing to annual colony deaths. Heavy metals, polycyclic aromatic hydrocarbons (PAHs), and microplastics have been detected in by-products of stingless bees, especially honey. Epidemiological research is crucial, including studies on pathogens associated with diseases, the effects of contaminants on bees, and the development of quality guidelines for stingless-bee products.

The integration of Digital Twin technology into active learning environments has been established as an innovative strategy to optimize engineering education. This study focuses on the development and evaluation of a learning tool based on Digital Twin technology, enabling interaction and communication between a physical teaching module and a virtualized environment representing the industrial cocoa production process. The system was operated by students using an S7-1200 PLC and an HMI interface developed in WinCC, facilitating real-time process monitoring and control via IoT. To assess its impact, an experimental design was implemented, comparing a pre-test using conventional teaching modules with a post-test incorporating Digital Twin technology. The results indicate a significant improvement in students’ accuracy and efficiency, with a 38% reduction in task execution time. This improvement is attributed to the system’s immersive and interactive capabilities, which allow for the simulation of actuator and sensor behavior under real-world conditions. These findings highlight the potential of Digital Twins not only as educational tools but also as valuable assets for industrial process optimization in the cocoa sector, aligning with Industry 4.0 principles.

An analysis of different geosites as territories of high geo-biodiverse value located within the Metropolitan District of Quito (DMQ) in Ecuador is performed based on the geoscientific inventory of thirty-six territorial zones and their geological history, cultural, and biological wealth. This is based on years of research and was complemented with the Geosites Assessment Model (GAM) methodology, the application of the criteria of which results in an impartial quantitative evaluation of each of these geosites, resulting in the determination of geographic areas with high tourist, archeological, and social potential. It also establishes a baseline to generate conservation strategies, scientific dissemination, and the determination of priorities in the management of the conservation of the geological heritage of the DMQ in Ecuador. The geological and geomorphological evolution of the DMQ grants this region a variety of sites formed by mainly cretaceous and quaternary volcanic and sedimentary deposits, geological faults, and other remarkable formations or sequences, which, together with the geoarchaeological sites, give a unique geohistorical value to the DMQ. In this context, the protection of each of the regionally important study sites for their scientific, educational, and cultural value in the geological area, as well as their scenic beauty and biodiversity, is essential. All of these attributes will be input to the future sustainable development approaches of the proposed UNESCO-DMQ Global Geopark by academic experts and researchers working in this territory. Additionally, this study also defines the need for the protection of each study area. The results of the evaluation will help to plan the effective management of the geosites based on their strengths and weaknesses and thus promote the Global Geopark. In this context, the value of the geodiversity of the DMQ has been recognized in this research, specifically for each of the geosites proposed as part of the UNESCO Global Geopark; the DMQ project, highlighting this geological and biodiverse heritage, contributes to direct benefits for the community and at an international level.

El suelo es un ecosistema vital para la supervivencia de toda especie dentro del planeta. Este recurso está en riesgo debido a procesos erosivos ocasionados por factores naturales y potenciados por actividades antropológicas. El presente estudio evaluó la calidad de los terrenos afectados y no por incendios forestales en la Comuna Centro del Pueblo Alangasí. Se evaluaron cinco parcelas (197, 200, 205, 274 y 274 B) a través de pruebas cualitativas (cromatografía de Pfaiffer) y cuantitativas (método gravimétrico LOI). Se caracterizó preliminarmente las bacterias de estas zonas, además de la realización de pruebas complementarias de medición de fósforo y glucosa. Los resultados demostraron que la parcela 205 (sin afectación) presentó la mejor calidad, mientras que la parcela 197 (afectada por incendio) mostró una ligera recuperación, en contraste con la parcela 200 (suelo tipo cangahua) que tuvo la condición más desfavorable. Asimismo, se encontró la predominancia de las bacterias Gram positivas, especialmente en las parcelas con suelos afectados por el fuego (197) y con mayor presencia de cangahua (200). En la parcela quemada se observó la acumulación de fósforo total, así como una buena correlación entre glucosa y crecimiento bacteriano. Concluyendo que factores como la cobertura vegetal, cantidad nutrientes, condiciones fisicoquímicas influyen en la salud del suelo. Palabras clave: suelo, incendio forestal, bacterias, materia orgánica, cromatografía, fósforo, glucosa, cangahua, calidad del suelo, diversidad microbiana

Anaplasmosis is a tick-borne disease (TBDs) caused by Anaplasma spp. In areas where TBDs are endemic, it is crucial to consider the animals’ immunological status in relation to these diseases. The true prevalence of bovine anaplasmosis, the percentage of animals with protective antibodies against this TBD, and the diagnostic characteristics of three tests (multiplex polymerase chain reaction (mPCR), competitive-inhibition enzyme-linked immunosorbent assay (cELISA), and blood smear (BS)) were estimated using a Bayesian approach. A total of 620 samples were collected in two subtropical areas of Ecuador. A significant finding of this study is that approximately 70% of cattle in those endemic areas harbored protective antibodies against Anaplasma marginale. This elevated percentage may stem from persistent exposure with a high pathogen prevalence in ticks. The decline in cELISA specificity must be attributed to cross-reactivity with protective antibodies against Anaplasma spp. It is crucial to interpret this test outcome alongside exposure history and clinical manifestations. The elevated apparent prevalence detected by cELISA and BS should be contextualized with mPCR results. The high seroprevalence and infrequent clinical outbreaks suggest that the pathogen has achieved endemic stability. This study provides valuable insights into the dynamics of anaplasmosis in endemic areas and may serve as a foundation for devising TBDs control strategies in these areas.

The study evaluates the implementation of check dams as nature-based solutions to address soil erosion, improve sediment quality, and enhance water retention in the Urku Huayku ravine, located on the Ilaló volcano in Ecuador. Weekly water and sediment samples were analysed from 2021 to 2023. Critical parameters measured include pH, electrical conductivity, nutrient concentrations, and organic matter content. Macroinvertebrates were collected to assess biodiversity changes using the Andean Biotic Index (ABI) and the Shannon Diversity Index. Results show significant improvements: water quality remained neutral (average pH 7.06), while sediment organic matter increased from 0.2% in 2021 to 3.2% in 2023. Additionally, biodiversity improved, with a 355.6% increase in macroinvertebrate abundance. Statistical tests confirmed the positive impact of check dams on sediment and water quality. The study also identified potential areas for additional check dam installations using QGIS analysis, emphasising steep slopes as ideal locations. This study demonstrates the efficacy of check dams in the restoration of degraded ecosystems and underscores their pivotal role in climate change mitigation. Through the enhanced storage of sediment organic matter, check dams facilitated the capture of approximately 58% of carbon. Additionally, they contributed to improved biodiversity. Further research is recommended to optimise dam placement and explore additional biodiversity indicators in Andes Mountain water bodies over 3000 m above sea level.

Laser-based powder bed fusion (L-PBF) technology stands out for its ability to create complex, high-performance parts, optimizing design freedom and material efficiency. Despite technical and financial challenges, it is attractive to industries where performance, weight reduction, and customization are critical. In L-PBF, relative density (RD) is a key factor that directly impacts the mechanical properties and overall quality of printed parts. However, predicting RD is a complex and costly task due to the numerous factors involved. This study addresses this need by creating a large-scale dataset for RD prediction in L-PBF, consisting of 1579 samples of commercial alloys from the literature. It includes printing conditions and other crucial inputs like protective atmosphere, powder size distribution, and part geometry. This dataset offers a valuable resource for researchers to benchmark their results, better understand key factors influencing RD, and validate models or explore new machine-learning approaches tailored to L-PBF.

Objectives This study highlighted the gap in the genetic characterization of marine bacteria, specifically within the genus Thiohalocapsa. This genus thrives in contaminated environments with high concentrations of sulfide, such as treated municipal wastewater. Thc. marina is a phototrophic purple bacterium known for its role in sulfur oxidation and bioremediation in marine aquaculture systems. To date, only one Thc. marina genome has been published in the GenBank database. This study enhances the understanding of the ecological adaptation and bioremediation capabilities of Thc. marina in treated municipal wastewater effluents. Data description We present a draft genome of Thc. marina LNA26 recovered from treated municipal wastewater effluents using shotgun metagenomic sequencing. The genome of Thc. marina LNA26 harbors 4,356,720 bp and contains 4,032 genes (3,936 CDSs, 50 RNA genes, and 46 pseudogenes), some of them involved in sporulation, siderophores biosynthesis, arsenate bioremediation, sulfide metabolism, capacity for nitrogen fixation, the biosynthesis of PHA, and NHPL bacteriocins. Thc. marina LNA26 exhibits 3 CRISPR Arrays and a high abundance of COGs in signal transduction, energy production, and cell wall biogenesis, indicating advanced environmental responsiveness, energy efficiency, and cellular robustness.