Repositorio Académico de la Universidad Católica del Maule
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Core-shell or Janus-like Fe0.5Ni0.5 nanostructures: a theoretical and experimental study
No full textIn this work, the formation FeNi bimetallic nanoparticles was investigated from an experimental and theoretical point of view. Molecular dynamics simulations were carried out in order to know the most stable arrangement of Fe and Ni atoms. The simulations considered nanostructures with three different sizes (6231, 10,000, and 21,366 atoms), and the configurations were forced to have Fe/Ni ratios approximately equal to one. The theoretical results pointed out the formation of an FeNi3 crystalline phase. Also, for different nanoparticle sizes, the lowest energy and stable structure is the Core-Shell FeNi3@Fe, even though the energy difference with the Janus-like structure (JN FeNi3/Fe) structure gets narrower as the number of atoms of the nanostructure increases. Considering these results, the synthesis of the FeNi bimetallic nanoparticles was carried out, and core-shell and Janus-like morphologies were expected to be seen. Interestingly, only core-shell NPs were observed through TEM and HAADF-STEM results, which clearly evidences the interference of the oleylamine (OAm) on the atomic arrangement of the final nanostructure. Based on the experimental results, as well as their discrepancy when compared to the theoretical ones, our hypothesis is that oleylamine is able to guide the nanostructure formation towards a core-shell morphology, by avoiding the appearance of Fe-rich agglomerates and by providing an active interactional site for OAm-Fe complexes with subsequent reduction on the surface of the FeNi3 core. As a result, Fe0 shell is produced, giving rise to a core-shell nanostructure
Circular economy in a recently transitioned high-income country in Latin America and the Caribbean: Barriers, drivers, strengths, opportunities, key stakeholders and priorities in Chile
No full textThis study explores Chile's efforts to adopt a circular economy (CE) to enhance sustainability and economic resilience as a newly high-income country in Latin America and the Caribbean. Conducting 22 semi-structured interviews, the research identifies barriers, drivers, strengths, opportunities, key stakeholders, and priorities for transitioning to a CE. Through qualitative analysis, the study examines Chile's CE landscape from cultural, political, technological, and economic perspectives, uncovering significant isomorphic pressures from international norms and sector spillovers. Findings indicate that despite proactive initiatives like the Roadmap for Circular Chile, several challenges persist. These include cultural resistance, limited public awareness and professional training, increased consumerism, inadequate regulatory enforcement, insufficient data and technological infrastructure outside metropolitan areas, an economy still reliant on resource extraction, and a lack of financial support from both public and private sectors. Conversely, Chile's robust regulatory framework, commitment to international environmental agreements, and growing sustainability interest among younger populations drive CE progress. Additionally, traditional knowledge, local entrepreneurship, and the Extended Producer Responsibility law support localised circular models. Opportunities are particularly significant in the mining, agriculture, and tourism sectors, where CE principles can foster innovation, economic growth, and sustainable resource management. The study emphasises the essential roles of government agencies, institutions, and businesses as key stakeholders. It highlights the need to enhance public awareness, reform educational systems to include comprehensive environmental education, and train a skilled workforce to support the CE transition. By addressing these areas, Chile can effectively advance its circular economy initiatives and achieve greater sustainability and economic resilience
Association between screen time and lifestyle parameters with executive functions in chilean children and adolescents: potential mediating role of health-related quality of life
Full text linkBackground/Objective: This study aimed to (i) investigate the association between lifestyle parameters (i.e., screen time [ST], food habits, and physical activity [PA]) and health-related quality of life (HRQoL) with executive functions (EFs, i.e., attention, inhibition, working memory, and cognitive flexibility) in Chilean children and adolescents, and (ii) determine the potential mediating role of HRQoL in the relationship between ST and EFs. Methods: A total of 511 children and adolescents (51.3% female) aged 10–17 years participated. Lifestyle parameters and EFs were evaluated. Results: Attention was inversely associated with ST (β = −19.51, p < 0.001) and positively associated with HRQoL (β = 4.17, p < 0.001). Inhibition was negatively linked to ST (β = −25.17, p < 0.001) and positively associated with HRQoL (β = 3.23, p = 0.041). Working memory was inversely related to ST (β = −28.89, p = 0.001) and positively associated with PA (β = 34.01, p < 0.001) and HRQoL (β = 4.22, p = 0.003). Cognitive flexibility was associated with ST (β = −26.76, p = 0.001), PA (β = 23.23, p = 0.047), and HRQoL (β = 4.91, p = 0.004). The indirect effect confirmed that HRQoL partially mediated the relationship between ST and EFs, including attention (5%), inhibition (3.18%), working memory (3.82%), and cognitive flexibility (5.3%). Conclusions: ST was inversely associated with all EFs assessed, and HRQoL showed a potential mediating role in these relationships
Probabilistic tephra fallout hazard maps for Sangay volcano, Ecuador
No full textSangay volcano (Ecuador) shows a quasi-continuous activity at least since the seventeenth century and has produced several eruptions which affected towns and cities at considerable distance (up to > 170 km). For this reason, despite its remote location, recent efforts were aimed at reviewing its volcanic history, quantifying the occurrence probability of four eruptive scenarios of different magnitude (Strong Ash Venting, Violent Strombolian, sub-Plinian, and Plinian) and the associated uncertainty, and, for each eruptive scenario, estimating the probability distribution of key eruptive source parameters (fallout volume, average plume height, and eruption duration). In this study, we utilize such information to produce probabilistic hazard maps and curves. To this aim, we use coupled plume and dispersal models (PLUME-MOM-TSM and HYSPLIT, respectively) with the application of a novel workflow for running an ensemble of thousands of simulations following a stochastic sampling of input parameters. We produced probabilistic hazard maps for each scenario by considering four ground load thresholds (i.e., 0.1, 1, 10, and 100 kg/m2) and two types of model initialization strategies, based on the elicited total deposit volume and on the elicited plume height, respectively, which produced non-negligible differences. In addition, we produced hazard curves for nine sites of interest from a risk perspective, corresponding to towns/cities potentially affected by tephra accumulation. Finally, we also derived combined maps by merging maps of single scenarios with their probability of occurrence as obtained from expert elicitation. Results indicate that in case of a future eruption, even for a moderate-scale one (Violent Strombolian), probability of tephra accumulation larger than 1 kg/m2 is relatively high (from 21 to 24% considering different model initializations) in the town of Guamote, i.e., the most severely affected site among those tested (43 km W of Sangay). For larger-scale events (i.e., sub-Plinian), the impact of tephra accumulation results to be significant even for the city of Guayaquil (176 km W of Sangay), with probability of tephra accumulation larger than 1 kg/m2 from 3 to 22% considering different model initializations. For maps combining single maps of historically observed scenarios, the probability (% - [5th-Mean-95th]) of having ≥ 10 kg/m2 for Guamote is [4-13-25] as maximum values
Hospital admissions for anxiety disorder, depression, and bipolar disorder and venous thromboembolism: a UK biobank prospective cohort study
No full textBackground
Few studies have investigated whether and which anxiety and affective disorders are associated with the risk of venous thromboembolism. We aimed to examine whether anxiety disorder, depression, and bipolar disorder increase the risk of venous thromboembolism, independent of socioeconomic confounders and each other, in a UK general population.
Methods
This is a prospective cohort study using UK Biobank. Participants were excluded if they were diagnosed with venous thromboembolism before the baseline assessment, if they were first diagnosed with anxiety disorder, depression, or bipolar disorder thereafter, or if they had missing sociodemographic data. Diagnosed anxiety disorder, depression, and bipolar disorder were ascertained through hospital admission data and incident venous thromboembolism, pulmonary embolism, and deep vein embolism were ascertained through both hospital admission and death certificate data. Hazard ratios were calculated, adjusted for sociodemographic confounders and comorbid anxiety and affective disorders.
Results
Our main analysis included 455,705 participants, of whom 53.6 % were female, with a mean age (standard deviation) of 56.6 (8.1) years. Anxiety disorder, depression, and bipolar disorder were associated with venous thromboembolism both before and after adjusting for sociodemographic confounders. After adjustment for comorbid anxiety and affective disorders, depression (HR: 2.00; 95 % CI: 1.68–2.38) and bipolar disorder (HR: 2.08; 95 % CI: 1.28–3.37) remained associated with venous thromboembolism, but anxiety did not (HR: 1.17; 95 % CI: 0.88–1.57). Similar results were found for pulmonary embolism and deep vein embolism.
Conclusions
Depression and bipolar disorder were associated with the risk of venous thromboembolism. Further research is required to understand the mechanism underlying their increased risk
Development of a solar-powered edge processing perimeter alert system with AI and LoRa/LoRaWAN integration for drone detection and enhanced security
No full textEdge processing is a trend in developing new technologies that leverage Artificial Intelligence (AI) without transmitting large volumes of data to centralized processing services. This technique is particularly relevant for security applications where there is a need to reduce the probability of intrusion or data breaches and to decentralize alert systems. Although drone detection has received great research attention, the ability to identify helicopters expands the spectrum of aerial threats that can be detected. In this work, we present the development of a perimeter alert system that integrates AI and multiple sensors processed at the edge. The proposed system can be integrated into a LoRa or LoRaWAN network powered by solar energy. The system incorporates a PDM microphone based on an Arduino Nano 33 BLE with a trained model to identify a drone or a UH-60 from an audio spectrogram to demonstrate its functionality. It is complemented by two PIR motion sensors and a microwave sensor with a range of up to 11 m. Additionally, the DC magnetic field is measured to identify possible sensor movements or changes caused by large bodies, and a configurable RGB light signal visually indicates motion or sound detection. The monitoring system communicates with a second MCU integrated with a LoRa or LoRaWAN communication module, enabling information transmission over distances of up to several kilometers. The system is powered by a LiPo battery, which is recharged using solar energy. The perimeter alert system offers numerous advantages, including edge processing for enhanced data privacy and reduced latency, integrating multiple sensors for increased accuracy, and a decentralized approach to improving security. Its compatibility with LoRa or LoRaWAN networks enables long-range communication, while solar-powered operation reduces environmental impact. These features position the perimeter alert system as a versatile and powerful solution for various applications, including border control, private property protection, and critical infrastructure monitoring. The evaluation results show notable progress in the acoustic detection of helicopters and drones under controlled conditions. Finally, all the original data presented in the study are openly available in an OSF repository
Use of games as a didactic resource in teaching and learning processes: perception of teachers in the school system
No full textIntroducción: El juego está presente en todo rango etario, asumiendo un rol muy importante en el aprendizaje y maduración de los niños y niñas. El juego genera un gran aporte al desarrollo social, cognitivo y emocional, además su sentido lúdico, favorece la creatividad, la socialización y la convivencia escolar especialmente en primera infancia. Objetivo: Esta investigación pretende identificar la percepción de profesores de primaria y secundaria respecto al juego como recurso didáctico en los procesos de enseñanza y aprendizaje. Metodología: Muestra compuesta por 16 docentes de una muestra por conveniencia, utilizando como técnicas de recogida de datos entrevistas semiestructuradas y grupos focales. La reducción y análisis cumplió con los siguientes pasos: transcripción, codificación y posterior categorización. Resultados: El juego es un elemento esencial en la vida y educación de los niños, jóvenes y adultos. En relación a lo anterior, los docentes describen sensaciones y aprendizajes positivos a través del juego, siendo un factor común en las clases de las diversas disciplinas escolares. Conclusiones: La perspectiva de los educadores frente al uso del juego es diversa en su aplicación y frecuencia, no obstante, en cuanto a la noción, relevancia y significado del juego como recurso didáctico es compartida
Antarctic fungal inoculation enhances drought tolerance and modulates fruit physiology in blueberry plants
No full textClimate change represents a direct threat to global food security, which includes prolonged droughts caused by global warming adversely affecting agricultural crop development and yield. Symbiotic associations between plants and extremophilic microorganisms have been shown to play a crucial role in enhancing plant adaptation to environmental stress. In this study, ‘Legacy’ blueberry plants were inoculated with two endophytic fungi, Penicillium chrysogenum and Penicillium brevicompactum, isolated from Antarctic plants, to evaluate their effects on fruit productions and plant responses, to water stress. The assays were conducted under drought conditions to simulate climate change, assessing the physiological and biochemical responses of fruits from inoculated and non-inoculated plants. Results indicated that inoculated plants exhibited an improvement in the physiological responses of plants under drought stress. The inoculated plants (W-E + ) consistently perform better than non-inoculated plants (W-E-) under water stress, particularly in water potential, PSII efficiency, and photosynthetic function. Meanwhile, the fruits obtained from these plants did not show differences in fruit size, while the weight, SSC/TA and firmness were greater in the inoculated fruits compared to the non-inoculated plants under drought stress. Additionally, the fruits showed a reduction in total phenolic and flavonoid content during stress periods, while enzymatic activities of superoxide dismutase and peroxidase were enhanced under the same conditions. These findings suggest that functional symbiosis with Antarctic microorganisms may alleviate drought-induced stress in plants by modulating their biochemical activities compared to non-inoculated counterparts
Physical Education teachers and school violence: a view from the classroom
No full textIntroducción: la violencia escolar es una preocupación global puesto que es causa de muchos decesos, siendo los estudiantes y profesores una población vulnerable a estas circunstancias. Objetivo: conocer la percepción de los docentes de Educación Física de una región del centro-sur de Chile frente a episodios de violencia física en el territorio escolar.
Metodología: se utilizó la metodología cualitativa, aplicando la técnica de entrevista semiestructurada mediante la que se recolectaron datos para conocer la impresión de los docentes en relación al fenómeno estudiado. Los participantes fueron docentes activos de tres centros educacionales y la muestra estuvo compuesta por ocho profesores de Educación Física.
Resultados: El total de entrevistados manifiesta que en su formación inicial docente no obtuvieron información ni preparación respecto a la violencia en el territorio escolar, como también, no se sienten capacitados para intervenir en dichas situaciones.
Conclusiones: Se concluye que es fundamental que las mallas curriculares implementen el concepto de convivencia escolar para la formación inicial del docente, por otro lado, resulta absolutamente necesario que los centros educativos ofrezcan oportunidades a los docentes para capacitarse en torno a la violencia, con el fin de contribuir e intervenir de mejor manera en situaciones difíciles
Insight into the relationships between chemical, protein and functional variables in the PBP/GOBP family in moths based on machine learning
No full textDuring their lives, insects must cope with a plethora of chemicals, of which a few will have an impact at the behavioral level. To detect these chemicals, insects use several protein families located in their main olfactory organs, the antennae. Inside the antennae, odorant-binding proteins (OBPs), as the most studied protein family, bind volatile chemicals to transport them. Pheromone-binding proteins (PBPs) and general-odorant-binding proteins (GOPBs) are two subclasses of OBPs and have evolved in moths with a putative olfactory role. Predictions for OBP–chemical interactions have remained limited, and functional data collected over the years unused. In this study, chemical, protein and functional data were curated, and related datasets were created with descriptors. Regression algorithms were implemented and their performance evaluated. Our results indicate that XGBoostRegressor exhibits the best performance (R2 of 0.76, RMSE of 0.28 and MAE of 0.20), followed by GradientBoostingRegressor and LightGBMRegressor. To the best of our knowledge, this is the first study showing a correlation among chemical, protein and functional data, particularly in the context of the PBP/GOBP family of proteins in moths