Repositorio Institucional UCSC (Univ. Católica de la Santísima Concepción)
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Identidad y valoración de la profesión en educadoras de párvulos en formación inicial en Chile
Get PDFEste estudio tuvo por objetivo comprender la identidad docente de educadoras de párvulos en formación inicial desde la valoración de la profesión. La metodología consistió en una investigación de campo, con diseño cualitativo y alcance descriptivo que indaga las textualidades de 41 estudiantes del séptimo semestre de la carrera de Educación de Párvulos de una universidad chilena. Se aplicó un formulario con preguntas abiertas y semiestructuradas, y los datos fueron procesados mediante un análisis de contenido temático con apoyo del software New NVivo. Se devela una dimensión afectiva de la identidad docente, junto a una dimensión vocacional profesional. Resulta de interés el contraste entre las categorías relacionadas al vínculo, la afectividad y confianza; junto a otras que apuntan a lo vocacional y trascendencia y/o significado de ser docente. En conclusión, en la identidad profesional de las futuras educadoras investigadas predomina lo afectivo por encima de lo vocacional profesional, lo que indica una transición entre visiones tradicionales que desvalorizan la profesión docente, hacia posturas más profesionales; hecho tensionado entre la posición individual de las futuras educadoras y visiones colectivas -familia, amigos, otros-. Para el resguardo del rigor científico se consideró criterios como credibilidad, transferibilidad, dependibilidad y conformabilidad
Upcycling of Fish Scales into a Au-Templated Mechanically Extractable Sturdy and Malleable Supported Catalyst for Cleansing Water
No full textDespite a decade of research and exploitation of fish scales for several applications, there is no report on fabricating supported catalysts for catalysis. Herein, simply by exploiting the metal binding and reductive potential of fish scales we autogenically bioengineered golden supported catalysts of ∼1.5 ± 0.4 cm2, sustainably. Providentially, the catalyst acquired mechanical sturdiness (∼65 ± 9 MPa), durability, flexibility, absorbency, and stability against diverse physicochemical barriers. Uniquely, these remarkable characteristics enabled the catalyst for reaction suitable fixative-batch or continuous flow catalysis, a rare compatibility. This was validated by performing large-volume (5 L) degradation of the textile sewage dye 4-nitrophenol (30 mg/L) at a (k) of 0.07 min–1, parallelly generating gram-scale quantities of 4-AP with a turnover frequency of 108 h–1. The continuous flow reactor was operable at a high flow rate of 1.5 mL/min, accommodating a high reduction of 4-NP of over 94%. Most importantly, the wide area of our catalyst made it feasible to hand-retrieve or exchange the catalyst for recycling and monitoring the reaction kinetics without the need for energy intensive processes. Finally, the collagenous biological nature of the support permitted ∼74 ± 5% recovery of gold by etching in Aqua-Regia. Overall, our biowaste-valued, cost-efficient, hand-retrievable, mechanically sturdy, and resilient catalyst with a highly flexible and durable nature can be generalized for reactor specific practical implementation of large scale heterogeneous catalysis
The Question of Anthropology in Jean-Luc Marion's Proposal
Get PDFEste artículo aborda la relación entre fenomenología y antropología desde la perspectiva de la “nueva fenomenología francesa”, con un enfoque especial en la obra de Jean-Luc Marion. Se analiza cómo conceptos clave como el adonado y el fenómeno saturado redefinen la subjetividad humana, proponiendo una “antropología negativa” que subraya las limitaciones intrínsecas del autoconocimiento y la dependencia del ser humano hacia la donación. Aunque Marion evita definiciones explícitamente antropológicas, su fenomenología ofrece herramientas para explorar la relación entre corporalidad, comunidad y trascendencia. Además, el artículo examina críticas contemporáneas al antropocentrismo y las implicaciones éticas de su enfoque fenomenológico. Finalmente, se destaca la necesidad de estudios futuros que articulen su fenomenología con preguntas antropológicas, enfatizando su relevancia en los debates filosóficos actuales
Percepção dos estudantes de Pedagogia em Educação Física quanto à sua prática profissional na modalidade virtual
Get PDFLa presente investigación buscó conocer las percepciones de estudiantes de Pedagogía en Educación Física (PEF) que desarrollaron su práctica profesional en modalidad virtual. Se evaluó a un total de 78 estudiantes pertenecientes a tres Instituciones de Educación Superior (IES) de Chile. Se aplicó una encuesta de percepción que considera 3 dimensiones, a) Dimensión Facilitadora, b) Dimensión Limitante, c) Dimensión Entrega de Contenidos. Se llevó a cabo un estudio cuantitativo, descriptivo, transversal y no experimental. Los resultados muestran que la percepción en la Dimensión Facilitadora los aspectos previos, de preparación y de condiciones óptimas son fundamentales para el desarrollo de la clase. La percepción en la Dimensión Limitante se aprecia que aspectos como duración de la clase y condiciones de conexión son ítems destacados por el estudiante. La percepción en la Dimensión Entrega de Contenidos de hábitos de vida saludable es relevante y la evaluación debe centrarse como proceso. Se concluye que la percepción y las consideraciones previas de ítems facilitadores, limitantes y entrega de contenidos son claves para un buen desempeño de una práctica profesional en modalidad virtual
Load Weight Estimation in Electric Forklifts via DC–DC Converter Power Signal Analysis of the Electro-Hydraulic Lifting System
Get PDFElectric forklifts are increasingly adopted in industrial environments due to their energy efficiency, reduced emissions, and lower operating noise compared to combustion alternatives. This paper presents a novel methodology for estimating the transported load weight in electric forklifts based on the output power signal of the DC–DC converter driving the electro-hydraulic lifting system. The proposed method leverages non-intrusive measurements of voltage and current to compute the lifting power, lifting speed, and energy, also allowing the computation of the lifting efficiency. The analysis confirmed that lifting energy is not linearly correlated with transported weight but lifting efficiency can be reasonably approximated as a function of lifting power and lifting speed, subsequently allowing the estimation of the transported mass. Experimental validation using 53 lifting events demonstrated that the methodology can estimate load weight with a reasonable mean absolute percentage error of 10.6% and 6.4% when using linear or multivariable regression analysis, respectively. These results demonstrate that the approach is sufficiently accurate for practical applications such as triggering load warnings when the estimated mass exceeds predefined safety thresholds
We need more voices, not less! Promoting employee voice through transformational leadership: The mediating role of organization-based self-esteem
Get PDFThis study examines the empowering effect of transformational leadership on employees’ promotive voice behavior. In addition, the mediating effect of organization-based self-esteem and the moderating effect of job insecurity were investigated. Survey data were collected from 128 Chilean employees (enrolled in an executive business specialization program at a major Chilean university) three times using a time-lagged design. Latent moderated structural equation modeling was conducted to test the research hypotheses using Mplus. Results indicate that organization-based self-esteem fully mediates the positive relationship between transformational leadership and employees’ promotive voice behavior. Job insecurity had no significant moderating effect. This article contributes to the literature on transformational leadership by (1) providing insight into the role of organization-based self-esteem as a mechanism of follower transformation, (2) studying the boundary condition of quantitative job insecurity that may influence the effectiveness of transformational leadership, and (3) using a three-wave time-lagged design to understand these relationships
Detection of near- and far-field traveling ionospheric disturbances during Tsunami Events over South Pacific
No full textLarge earthquakes and tsunamis often occur around the Pacific Ring of Fire, in which Traveling Ionospheric Disturbances (TIDs) have been observed after these events. Sometimes (depending on seismic source features), TIDs can be observed near the epicenter of the generated earthqucovering 14ake due to the shock-acoustic wave. Additionally, TIDs can be induced by tsunamis due to the generated gravity waves and be detected several thousand kilometers away from the source. TIDs can be detected by analyzing Total Electron Content (TEC), which is calculated, indirectly, using signals from Global Navigation Satellite System (GNSS) receivers. The procedure allows for studying the ionospheric disturbance with a good spatial and temporal resolution. This study aims to identify tsunami-induced TIDs in the near- and far-fields following significant events in the Oriental and Occidental South Pacific Ocean. The selection criteria covering 14 tsunamis that occurred between 2010 and 2021 generated by earthquakes with Mw > 7.8 and depth less than 50 km. Tsunamis were modeled and compared with the TIDs obtained from TEC deviations. Near-field and far-field TIDs observed in hodochrons differ primarily in the clarity of their association with tsunamis. The simulated tidal gauges show a possible connection with the observed TEC anomalies, behaving similarly but with different delay times, showing some events even hours in advance. This potential correlation between TID parameters and tsunamis propagated in the Pacific Ocean can contribute to understanding the involved mechanisms and facilitate the development of near real-time early warning systems
Behavioral Responses of Galaxias platei to Salmo trutta: Experimental Evidence of Competition and Predation Risk
Get PDFThe adverse impacts of invasive salmonids on native galaxiids are well documented at the population level in the freshwater ecosystems of the Southern Hemisphere. However, the mechanism underlying these interactions and sub-lethal effects of salmonids on native galaxiids at the individual level remain poorly understood. In this study, a series of controlled experiments was conducted to assess sub-lethal interactions between invasive brown trout (Salmo trutta) and the native Galaxias platei at an individual level. The microhabitat preferences of G. platei were evaluated in response to potential competition with juvenile brown trout and predation risk from piscivorous adults. In addition, the swimming capacity of G. platei was assessed to determine their ability to escape predation. The results show that at increasing densities of juvenile brown trout, G. platei fails to increase refuge use and are more frequently observed in open habitats. Furthermore, G. platei juveniles exhibit significantly lower swimming capacity compared to brown trout. In the presence of predatory trout, G. platei does not display a heightened preference for refuge habitats. These findings suggest that the behavioral response of G. platei could be insufficient to reduce competition and predation risks posed by brown trout and potentially other salmonids
Adversarial attacks in demand-side electricity markets
No full textDetecting and characterizing malicious operations in electricity markets presents substantial challenges due to the innate complexity of power networks. This paper explores adversarial attacks in electricity markets, i.e., we consider the scenario in which malicious market participants make undetectable changes to the input data of other participants, resulting in significant negative impacts on their operations. We propose a novel methodology to generate adversarial attacks, which leverages linear optimization theory and statistical learning to generate suboptimal, feasible solutions or super-optimal, infeasible solutions that convincingly resemble optimal solutions. The methodology is general and applicable for generating adversarial attacks on optimization-based decision systems. We use it to analyze the potential economic losses, policy making, and social consequences resulting from compromised demand-side operations. In particular, we focus on scenarios where certain demand side-players, i.e., microgrids, or prosumers in a general sense, engage in malicious activities by targeting other microgrids and the independent system operator. We model the electricity market dynamics using an equilibrium problem with equilibrium constraints (EPEC). To make the model easier to solve, the EPEC is reformulated using a combination of the Fisher–Burmeister function and strong duality theorem. Results show that microgrids can artificially decrease its consumption by up to 12% without triggering alarms. Additionally, this amount can be increased by an additional 14% to 22%, contingent on the strategy employed to monitor the observable variables. We also study the implications of the increasing utilization of solar generation, showing its potential to mitigate the impact of adversarial attacks while also introducing new risks to the system