Repositorio Institucional UCSC (Univ. Católica de la Santísima Concepción)
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Explorando la conciencia histórica: Análisis de narrativas de estudiantes de pedagogía en historia sobre el estallido social chileno (2019-2020)
No full textConfigurações de significado do corpo acadêmico de educação superior com relação aos princípios de inclusão e diversidade
Get PDFLa comprensión de los principios de inclusión y diversidad es un proceso dialógico y recursivo que los sujetos construyen y reconstruyen a lo largo de su trayectoria de vida. Los disensos críticos de inclusión la comprenden desde las relaciones de alteridad, mirada como un proceso interpelativo. A su vez, la diversidad es comprendida como un proceso de reconocimiento de las diferencias y diversidades de los sujetos. El objetivo de la investigación es develar la configuración de significado respecto a la inclusión y diversidad desde los discursos activos del cuerpo académico que forma educadores desde las experiencias vividas. La investigación se enmarcó en un paradigma interpretativo de naturaleza cualitativa, con un diseño fenomenológico hermenéutico. Se utilizó una muestra por conveniencia de diez participantes a los que se les realizó una entrevista semiestructurada. Los participantes configuran el significado de inclusión y diversidad como un espacio multifactorial para la expresión de la singularidad, en la que el cuerpo académico y el estudiantado pueden expresar su diversidad como elemento enriquecedor del proceso educativo. Esto se produce por la construcción de experiencias formativas que responden a un diseño universal de la enseñanza y del aprendizaje
Four microlensing giant planets detected through signals produced by minor-image perturbations
Get PDFAims. We investigated the nature of the anomalies appearing in four microlensing events KMT-2020-BLG-0757, KMT-2022-BLG-0732, KMT-2022-BLG-1787, and KMT-2022-BLG-1852. The light curves of these events commonly exhibit initial bumps followed by subsequent troughs that extend across a substantial portion of the light curves.
Methods. We performed thorough modeling of the anomalies to elucidate their characteristics. Despite their prolonged durations, which differ from the usual brief anomalies observed in typical planetary events, our analysis revealed that each anomaly in these events originated from a planetary companion located within the Einstein ring of the primary star. It was found that the initial bump arouse when the source star crossed one of the planetary caustics, while the subsequent trough feature occurred as the source traversed the region of minor image perturbations lying between the pair of planetary caustics.
Results. The estimated masses of the host and planet, their mass ratios, and the distance to the discovered planetary systems are (Mhost/M⊙, Mplanet/MJ, q/10−3, DL/kpc) = (0.58−0.30+0.33, 10.71−5.61+6.17, 17.61 ± 2.25, 6.67−1.30+0.93) for KMT-2020-BLG-0757, (0.53−0.31+0.31, 1.12−0.65+0.65, 2.01 ± 0.07, 6.66−1.84+1.19) for KMT-2022-BLG-0732, (0.42−0.23+0.32, 6.64−3.64+4.98, 15.07 ± 0.86, 7.55−1.30+0.89) for KMT-2022-BLG-1787, and (0.32−0.19+0.34, 4.98−2.94+5.42, 8.74 ± 0.49, 6.27−1.15+0.90) for KMT-2022-BLG-1852. These parameters indicate that all the planets are giants with masses exceeding the mass of Jupiter in our solar system and the hosts are low-mass stars with masses substantially less massive than the Sun
A three-field mixed finite element method for the convective Brinkman–Forchheimer problem with varying porosity
No full textIn this paper we present and analyze a new mixed finite element method for the nonlinear problem given by the stationary convective Brinkman–Forchheimer equations with varying porosity. Our approach is based on the introduction of the pseudostress and the gradient of the porosity times the velocity, as further unknowns. As a consequence, we obtain a mixed variational formulation within a Banach spaces framework, with the velocity and the aforementioned tensors as the only unknowns. The pressure, the velocity gradient, the vorticity, and the shear stress can be computed afterwards via postprocessing formulae. A fixed-point strategy, along with monotone operators theory and the classical Banach theorem, are employed to prove the well-posedness of the continuous and discrete systems. Specific finite element subspaces satisfying the required discrete stability condition are defined, and optimal a priori error estimates are derived. Finally, several numerical examples illustrating the performance and flexibility of the method and confirming the theoretical rates of convergence, are reported
Electrochemical properties of nanoscale Cu Co spinel ferrite system: A promising positive electrode for high performance supercapacitors
No full textThere is an enormous demand for energy storage applications with a high specific capacity, superior energy and power density, and long-life cycles because of the increase in portable electronic appliances. The use of ternary metal oxide electrode materials for energy storage applications in supercapacitors based on multi-redox sites has gained more attention from researchers due to their outstanding specific capacitance and numerous redox sites. Copper cobalt ferrites (CuCoFe2O4) nanoparticles (NPs) have been synthesised by the simple microwave combustion method and employed as a positive electrode material for energy storage in supercapacitors (SCs). To study the physical and electrochemical properties of the prepared nanoparticles by XRD, FTIR, SEM-EDX, HR-TEM, and electrochemical analysis have been carried out. X-ray diffraction planes indicating the cubic spinel structure with a space group of Fd-3m and the crystalline phase purity of the synthesised CuCoFe2O4 NPs were also characterized by Rietveld refinement. HR-TEM analysis of the existing agglomeration of particles and SAED pattern shows the excellent crystalline nature of the materials. The CuCoFe2O4 electrode obtained an outstanding specific capacitance of 237.5 F g−1 at 0.5 A g−1 current density in a 3 M KOH electrolyte in a standard three-electrode system. Further fabricated of a solid-state asymmetric supercapacitor (ASC) device by using CuCoFe2O4 NPs and activated carbon (AC) as the positive and negative electrodes, respectively. This ASC device offers a superior energy density value of 16 Wh kg−1 and a power density of 8048 W kg−1. In addition, the ASCs device exhibits cycle stability of 82 % after 10,000 GCD charge and discharge cycles at a current density of 40 A g−1, displaying its high cycling stability
Ethylene elimination using activated carbons obtained from Baru (Dipteryx alata vog.) waste and impregnated with copper oxide
Get PDFEthylene is a plant hormone regulator that stimulates chlorophyll loss and promotes softening and aging, resulting in a deterioration and reduction in the post-harvest life of fruit. Commercial activated carbons have been used as ethylene scavengers during the storage and transportation of a great variety of agricultural commodities. In this work, the effect of the incorporation of copper oxide over activated carbons obtained from baru waste was assessed. Samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption at −196 °C, field-emission scanning electron microscopy (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDS), and infrared (IR) spectroscopy. The results showed that the amount of ethylene removed using activated carbon obtained from baru waste and impregnated with copper oxide (1667 μg g−1) was significantly increased in comparison to the raw activated carbon (1111 μg g−1). In addition, carbon impregnated with copper oxide exhibited better adsorption performance at a low ethylene concentration. Activated carbons produced from baru waste are promising candidates to be used as adsorbents in the elimination of ethylene during the storage and transportation of agricultural commodities at a lower cost
The importance of feeding fast when thieves are around: A case study on Whimbrels foraging on a wave‐exposed sandy beach in Southern Chile
No full textPrey profitability is one of the most important factors influencing prey selection. This factor varies along with both prey size and handling time. Thus, large prey are generally highly profitable for consumers and boost competition. Kleptoparasitism is a form of competition in which an individual steals food previously obtained by another individual. Accordingly, handling large prey should increase the likelihood of kleptoparasitism occurrence, but these relationships remain poorly understood. Here, we studied kleptoparasitism occurrence by the Brown‐Hooded Gull (Chroicocephalus maculipennis – Laridae) on Whimbrels (Numenius phaeopus hudsonicus – Scolopacidae) preying on intertidal Mole Crabs (Emerita analoga) in a wave‐exposed sandy beach in southern Chile. Generalized linear models, fitted to data from focal‐individual video sequences, showed that kleptoparasitism probability had a positive sigmoidal response to handling time. Moreover, with an increase of 1 s in handling time, a Whimbrel doubled its probability of being kleptoparasitized. Additionally, the odds of being kleptoparasitized were 17% higher with an increase of 10 mm in prey length and 47% higher with an increase of one gull per host. However, the effect of handling on kleptoparasitism probability slightly decreased (2%) with an increase of 10 mm in prey size class. Our results suggest the existence of a threshold time in which consumers can handle their prey before kleptoparasitism probability is too high. Nevertheless, Whimbrel's mean intake rate reached 0.15 ± 0.13 kJ s−1, allowing Whimbrels to theoretically meet their energetic requirements despite losing some prey to kleptoparasites. This study provides new insight into a common form of competition among consumers, highlighting the importance of prey handling time for shorebirds with a restricted foraging time driven by tidal cycles
Do board gender diversity and remuneration impact earnings quality? Evidence from Spanish firms
No full textPurpose: This study aims to investigate how gender diversity and remuneration of boards of directors’ influence earnings quality for Spanish-listed firms.
Design/methodology/approach: The sample includes 105 nonfinancial Spanish firms from 2013 to 2018, corresponding to an unbalanced panel of 491 firm-year observations. The primary empirical method uses a Tobit semiparametric estimator with firm- and industry-level fixed effects and an innovative set of measures for earnings quality developed by StarMine.
Findings: Results exhibit a positive correlation between increased gender diversity and a firm’s earnings quality, suggesting that a gender-balanced board of directors is associated with more transparent financial reporting and informative earnings. We also find a nonmonotonic, concave relationship between board remuneration and earnings quality. This indicates that beyond a certain point, excessive board compensation leads to more opportunistic manipulation of financial reporting with subsequent degradation of earnings quality.
Research limitations/implications: This study only covers nonfinancial Spanish listed firms and is silent about how alternative board features’ influence earnings quality and their informativeness.
Originality/value: This study introduces measures of earnings quality developed by StarMine that have not been used in the empirical literature before as well as measures of board gender diversity applied to a suitable Tobit semiparametric estimator for fixed effects that improves the precision of results. In addition, while most of the literature focuses on Anglo-Saxon countries, this study discusses board gender diversity and board remuneration in the underexplored context of Spain. Moreover, the hand-collected data set comprising financial reports provides previously untested board features as well as a nonlinear relationship between remuneration and earnings quality that has not been thoroughly discussed before
Influencia de la identidad docente en la elección de estrategias didácticas para la enseñanza del lenguaje
Get PDFLa identidad docente se concibe como un proceso dinámico y complejo que provee un marco importante para explorar las diversas interacciones generadas durante el ejercicio profesional. El papel que desempeña el diálogo y la comunicación efectiva resulta relevante en esta construcción. En este contexto, el presente estudio se propuso determinar la influencia de la identidad en la elección de estrategias didácticas para la enseñanza del lenguaje. La investigación es de tipo descriptivo con enfoque cualitativo. Se efectuó un muestreo no probabilístico por conveniencia, constituido por 20 profesores de lenguaje de enseñanza media y educación básica. La recolección de información se llevó a cabo a través de dos instancias: 1) Aplicación de cuestionario. 2) Realización de grupos de discusión grupal. Ambas instancias hicieron posible la profundización en torno a la identidad docente y en cómo ella incide en la definición de estrategias para los procesos de enseñanza-aprendizaje en el aula de lenguaje. Los hallazgos de este estudio muestran una conexión entre la identidad del profesorado y el rendimiento de las técnicas de enseñanza. A través de un análisis de contenido, se identificaron dos categorías emergentes: 1. El diálogo y la comunicación como elementos centrales de la identidad docente. 2. La formación valórica y ética como impulsor de prácticas pedagógicas exitosas. En este sentido, se destaca que la comunicación y el diálogo, tanto dentro como fuera del aula, emergen como factores críticos para fomentar el aprendizaje interactivo, la colaboración y la mejora continua del proceso educativo. Junto a ello, se releva el papel ético del docente de lenguaje, quien, desde su identidad profesional, busca inculcar valores éticos y morales en sus estudiantes. Estos hallazgos resaltan la importancia de adoptar un enfoque integral de educación socioemocional para garantizar una formación educativa significativa