Repositorio Institucional UCSC (Univ. Católica de la Santísima Concepción)
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Development of speed in children aged 11 to 12 years practicing athletics -quasi-experimental non-randomized study
Get PDFBackground: The development of speed in primary school children can be improved during the sensitive period of this quality.
Objective: To analyze the effects of speed and reaction exercises on speed in athletic children between 11 and 12 years old.
Methods: Quasi-experimental, non-randomized study conducted between September 2022 and March 2023, in which 42 children aged 11-12 years belonging to the Basic sports school No. 8 in Kirov (Russia) were assigned to a control (n=21) and experimental (n=21) group. The classes in the control group were carried out according to the usual athletic training plan, while the experimental group used exercises for speed development. Both groups were evaluated by the tests ''Running on the spot'', ''Shuttle running 10x5 meters'' and ''Sprint 10 meters''.
Results: The control group did not present significant improvements (p>0.05), while the experimental group reported significant improvements in ''Running on the spot'' (20%; p<0.05), ''Shuttle running 10x5 meters'' (15%; p<0.05) and ''Sprint 10 meters'' (8.6%; p<0.05).
Conclusion: An exercise program focused on speed development in children aged 11-12 years can significantly improve the different manifestations of speed
Sustainable food dishes: Selection of indicators for their evaluation and communication in Chilean foodservices
No full textThe foodservice sector has grown rapidly due to the increase in meals out of home. Thanks to the enormous number of meals served daily, making changes to reduce the environmental footprint of their menus could have a positive impact on the sustainability of the food system. The objective of this study was to select indicators to evaluate and communicate the sustainability of culinary preparations offered by foodservices. A bibliographic search of indicators was carried out, which were subsequently subjected to validation regarding their relevance by a group of experts. The indicators finally selected, carbon footprint, water footprint, presence of meat and/or animal products, presence of local ingredients and generation of waste in processing, were applied to traditional Chilean recipes and the results were presented to two discussion groups of consumers to evaluate their understanding and usefulness. When these indicators were applied to 10 Chilean recipes, it was found that those containing meat as an ingredient were less sustainable. A group of consumers invited for validation found the way these indicators were communicated understandable and useful. It is expected that the validation of these indicators will be useful for communicating to services and consumers the sustainability of dishes in foodservices
Load-level isolator model for pallets on industrial storage racks and validation with experimental results
No full textThis paper introduces a system allows for seismic isolation of the pallet from the rack in the down-aisle direction, occupies minimal vertical space (5 cm) and ±7.5 cm of deformation range. A conceptual model of the isolation system is presented, leading to a constitutive equation governing its behavior. A first experimental campaign studying the response of the isolation system's components was conducted to calibrate the parameters of its constitutive equation. A second experimental campaign evaluated the response of the isolation system with mass placed on it, subjected to cyclic loading. The results of this second campaign were compared with the numerical predictions using the pre-calibrated constitutive equation, allowing a double-blind validation of the constitutive equation of the isolation system. Finally, a numerical evaluation of the isolation system subjected to a synthetic earthquake of one component. This evaluation allowed verifying attributes of the proposed isolation system, such as its self-centering capacity and its effectiveness in reducing the absolute acceleration of the isolated mass and the shear load transmitted to the supporting beams of the rack
High intensity interval training based on parasympathetic activity and its impact on the cardi-orespiratory capacity of university students. Randomized Controlled Trial
Get PDFIntroducción: El entrenamiento interválico de alta intensidad tradicionalmente se prescribe mediante valores fijos que pueden ser insuficientes para la generación de perturbaciones homeostáticas.
Objetivo: Evaluar cómo un programa de entrenamiento interválico de alta intensidad, guiado por la actividad parasimpática, afecta la capacidad cardiorrespiratoria de estudiantes universitarios físicamente activos.
Método: Estudio controlado, paralelo y aleatorizado con cegado simple. 26 universitarios físicamente activos fueron divididos en un grupo control y un grupo experimental para ser sometidos a 4 semanas de un entrenamiento interválico de alta intensidad. La capacidad cardiorrespiratoria se estimó mediante el Step Test 3x1 y la variabilidad de la frecuencia cardiaca se determinó mediante una prueba ortostática
Resultados: Ambos grupos mostraron cambios significativos en el VO2 pico, siendo el grupo experimental el que mostró una mejora superior (C.V = 14%; p = 0,003; d = 1,16) comparado al grupo control (C.V = 11%; p = 0,01; d = 0,7). En cuanto a la actividad parasimpática, solo el grupo experimental mostró cambios significativos en la frecuencia cardiaca (C.V = 10,5%; p = 0,004; d = 1,28) y raíz cuadrada media de las diferencias sucesivas (C.V = 19,7%; p = 0,02; d = 1,16) en posición decúbito supino.
Conclusión: Un entrenamiento interválico de alta intensidad de alto volumen y corta duración prescrito en base a la actividad parasimpática puede ser un estímulo eficaz para mejorar la capacidad cardiorrespiratoria en estudiantes universitarios físicamente activos
Differential scanning calorimetry in drug-membrane interactions
Get PDFDifferential Scanning Calorimetry (DSC) is a central technique in investigating drug - membrane interactions, a critical component of pharmaceutical research. DSC measures the heat difference between a sample of interest and a reference as a function of temperature or time, contributing essential knowledge on the thermally induced phase changes in lipid membranes and how these changes are affected by incorporating pharmacological substances. The manuscript discusses the use of phospholipid bilayers, which can form structures like unilamellar and multilamellar vesicles, providing a simplified yet representative membrane model to investigate the complex dynamics of how drugs interact with and penetrate cellular barriers. The manuscript consolidates data from various studies, providing a comprehensive understanding of the mechanisms underlying drug - membrane interactions, the determinants that influence these interactions, and the crucial role of DSC in elucidating these components. It further explores the interactions of specific classes of drugs with phospholipid membranes, including non-steroidal anti-inflammatory drugs, anticancer agents, natural products with antioxidant proper ties, and Alzheimer’s disease therapeutics. The manuscript underscores the critical importance of DSC in this field and the need for continued research to improve our understanding of these interactions, acting as a valuable resource for researchers
Effects of video-guided active breaks with curricular content on mental health and classroom climate in chilean schoolchildren aged 6 to 10: Study protocol for a multicentre randomized controlled trial
Get PDFBackground: The incidence of mental health issues in children is increasing worldwide. In Chile, a recent surge in reports of deteriorating mental health among school populations and an increase in complaints related to poor school climate have been observed. Physical activity, specifically active breaks in the classroom, has shown positive effects on children’s health. However, evidence regarding its impact on mental health and school climate in children is limited.
Objective: This work outlines the design, measurements, intervention program, and potential efficacy of the “Active Classes + School Climate and Mental Health” project. This project will assess a 12-week program of active breaks through guided videos with curricular content in the school classroom, and its effects on mental health and school climate as its primary indicators. Additionally, it will measure physical activity, physical fitness, motor competence, and academic performance in students aged 6–10 years in the Biobío province, Chile, as secondary indicators.
Methodology: A multicenter randomized controlled trial involving 823 students from 1st to 4th grade (6–10 years old), six schools (three intervention and three control) will be conducted in the Biobío region, Chile. Participants belonging to the intervention group will implement video-guided active breaks through the “Active Classes” web platform, featuring curricular content, lasting 5–10 min and of moderate to vigorous intensity physical activity, twice a day, Monday to Friday, over a span of 12 weeks.
Expected Results/Discussion: To our knowledge, this will be the first study in Chile to evaluate the effects of incorporating video-guided active breaks with curricular content on mental health variables and school climate in schoolchildren. Thus, this study contributes to the scarce evidence on the effects of video-guided active breaks on mental health variables and school climate in schoolchildren worldwide. Additionally, it will provide crucial information about active teaching methodologies that have the potential to positively contribute to the wellbeing of students, thus addressing the problems of mental health and climate in Chilean schools. ClinicalTrials.gov ID NCT06423404
Pedagogical practice of Physical Education teachers, systematic review according to the guidelines: PRISMA
Get PDFEste artículo tiene como objetivo realizar una revisión sistemática de los estudios llevados a cabo sobre las prácticas pedagógicas en educación física en diversos contextos. Se aborda específicamente las prácticas pedagógicas en educación física, así como otros escenarios donde se aplicaron estrategias para la enseñanza de esta asignatura. La revisión se basa en la consulta de las bases de datos Web of Science y Scopus-Elsevier, abarcando los últimos cinco años (2019-2023) en Sudamérica. A partir de esta revisión, se seleccionaron artículos que detallan experiencias formativas destinadas a estimular las prácticas pedagógicas en diversos entornos y niveles educativos. Se identificaron revisiones sistemáticas centrándose en aspectos específicos como la formación en valores, prácticas reflexivas en evaluación y otros aportes relacionados con la educación física. En términos de metodología, prevalecieron los enfoques cualitativos, siendo la entrevista el principal instrumento de recopilación de información. Por otro lado, en las metodologías cuantitativas, los cuestionarios (especialmente la escala Likert en la evaluación de competencias y autoeficacia) fueron los más utilizados. Los resultados obtenidos posicionan a Chile como líder en las investigaciones sobre este tema en la región. En conclusión, se observa una tendencia que señala que el énfasis en la cualificación de las prácticas pedagógicas del docente en educación física se concentra principalmente en su actuación profesional. Este enfoque se justifica al considerar que es desde este punto que se desarrollan las competencias necesarias para abordar las demandas actuales en los contextos específicos de Latinoamerica
Spatio-temporal variability of turbidity derived from Sentinel-2 in Reloncaví sound, Northern Patagonia, Chile
Get PDFTurbidity is associated with the loss of water transparency due to the presence of particles, sediments, suspended solids, and organic or inorganic compounds in the water, of natural or anthropogenic origin. Our study aimed to evaluate the spatio-temporal variability of turbidity from Sentinel-2 (S2) images in the Reloncaví sound and fjord, in Northern Patagonia, Chile, a coastal ecosystem that is intensively used by finfish and shellfish aqua culture. To this end, we downloaded 123 S2 images and assembled a five-year time series (2016–2020) covering five study sites (R1 to R5) located along the axis of the fjord and seaward into the sound. We used Acolite to perform the atmospheric correction and estimate turbidity with two algorithms proposed by Nechad et al. (2009, 2016 Nv09 and Nv16, respectively). When compared to match-up, and in situ measurements, both algorithms had the same performance (R2 = 0.40). The Nv09 algorithm, however, yielded smaller errors than Nv16 (RMSE = 0.66 FNU and RMSE = 0.84 FNU, respectively). Results from true-color imagery and two Nechad algorithms singled an image from the austral autumn of 2019 as the one with the highest turbidity. Similarly, three images from the 2020 austral autumn (May 20, 25, 30) also exhibited high turbidity values. The turbid plumes with the greatest extent occurred in the autumn of 2019 and 2020, coinciding with the most severe storms and runoff events of the year, and the highest turbidity values. Temporal trends in turbidity were not significant at any of the study sites. However, turbidity trends at sites R1 and R2 suggested an increasing trend, while the other sites showed the opposite trend. Site R1 recorded the highest turbidity values, and the lowest values were recorded at R5 in the center of the sound. The month of May was characterized by the highest turbidity values. The application of algorithms from high-resolution satellite images proved to be effective for the estimation and mapping of this water quality parameter in the study area. The use of S2 imagery unraveled a predictable spatial and temporal structure of turbidity patterns in this optically complex aquatic environment. Our results suggest that the availability of in situ data and the continued evaluation of the performance of the Nechad algorithms can yield significant insights into the dynamics and impacts of turbid waters in this important coastal ecosystem
Navigating job satisfaction in family firms during crisis
Get PDFOccupational health is one of the aspects significantly affected during crisis periods. It is essential to learn about the factors that improve organizational capacity in coping with such shocks. This study investigates how the working environment of a family business influences job satisfaction during crises. Conducting a survey with 516 employees at the peak of the pandemic, the research utilizes structural equation analysis, revealing that family business environments can mitigate burnout, enhance affective commitment, and consequently, boost job satisfaction. The study highlights the need to manage burnout and utilize resources, such as employee commitment, for family firms to sustain job satisfaction amidst disruptions. It deepens the comprehension of family businesses’ crisis response, emphasizing the significance of human resource commitment and management. The investigation illuminates the dynamic interplay between the work environment, employee well-being, and organizational resilience, providing valuable insights for both theoretical understanding and practical application
Photothermic energy harvesting in reduced graphene oxide nanosheets intercalated with vanadium nitride as pseudocapacitive electrode
No full textThe photothermal energy conversion mechanism in pseudocapacitive nanoelectrodes endures temperature-enervated power dissipation due to self-heating, leading to rapid heating and cooling cycles during the redox reactions triggered by plasmonic excitation. Herein, we report on vanadium nitride (VN)-intercalated reduced graphene oxide (RGO) nanosheets (VN@RGO) as a photoresponsive pseudocapacitive electrode material. Finite-difference time-domain (FDTD) simulations were used to analyze the photothermal-driven localized self-heating considering the complex dielectric properties of VN@RGO. The effect of morphology and stoichiometry on the polarization-induced electric field intensity (|E|2), power absorption (Pabs), and current density (J) of the VN@RGO system has been systematically explored. Both the simulation and experimental results complement each other. This study delineates electrically coupled thermal attenuation in VN@RGO, overcoming the limitations related to potential modulation of the electrode material. VN@RGO exhibits excellent electrochemical performance in the half-cell and full-cell modes of a symmetric supercapacitor, achieving maximum specific capacitances of 276 and 56 F g–1 at a current density of 0.1 A g–1, respectively