Gwangju National University of Education

Fixed-effects regression models are commonly used in longitudinal studies as a means to estimate causal effects while controlling for unobserved time-invariant confounders. However, unobserved time-varying confounding remains potentially problematic, and identifying and measuring such confounders can be resource-intensive and costly. We propose the Time-Varying Confounding Structural Equation Model (TVC-SEM), a simple longitudinal model that builds on previous “common factor” models and which can serve as a robustness check for the assumption of no unobserved time-varying confounding in the fixed-effects approach. We posit a model with a latent autoregressive variable Z it , which represents the combined influence of both time-invariant and time-varying unobservables, and which is linked to the independent and dependent variables over time. Through Monte Carlo simulations and analyses of data from the Early Childhood Longitudinal Studies Kindergarten cohort (ECLS-K) and the Rural Substance Abuse and Violence Project (RSVP), we show that, under most conditions, TVC-SEM provides less biased estimates than several variants of the traditional fixed-effects model. Our proposed approach offers applied researchers a practical check for gauging the extent to which the fixed-effects assumption of no time-varying confounding may produce bias in the estimation of causal effects.

Abstract An important photoelectrocatalyst for solar‐driven hydrogen synthesis is n‐type bismuth vanadate (BiVO 4 ) because of its straddling band alignment with water splitting potentials, visible‐active bandgap (2.4 eV), and outstanding theoretical efficiency. Unfortunately, the actual feasibility of pure BiVO 4 photoanodes is hampered by their restricted hole diffusion length and slow surface oxidation rates. We offer a novel FeOOH@Ni‐doped BiVO 4 photoanode manufacturing method that addresses these issues by dual‐modifying a nanoporous BiVO 4 with bulk nickel doping and a surface iron oxyhydroxide oxygen evolution catalyst (OEC). The solar‐driven water oxidation experiments revealed that the as‐synthesized FeOOH@Ni‐doped BiVO 4 showed a high photocurrent density of 1.62 mA cm −2 at 1.0 V RHE , representing an approximately two‐fold increase with respect to the pristine counterpart. Additionally, the applied bias photon‐to‐current conversion efficiency (ABPE) of the rationally engineered FeOOH@Ni‐doped BiVO 4 photoanode was significantly improved from 0.47% to 0.83%, and the surface charge separation efficiency reached a maximum of 23%. The long‐term photostability studies demonstrated maximum photocurrent retention for 10 h without any significant degradation. We believe our findings open a new avenue for developing a next‐generation photoanode and providing a rational strategy for designing an efficient solar‐assisted water splitting system.

Contemporary politics faces a coupled crisis: accelerating AI and intensifying ecological breakdown.This article argues that integrating posthumanism with green republicanism offers a coherent normative and institutional paradigm for governing the Anthropocene.Posthumanism decenters humans by treating humans, nonhuman animals, technologies, and abiotic environments as entangled participants in world-making, thereby expanding the community of justice.Green republicanism adapts civic republican ideals of the common good and freedom as nondomination to ecological limits and intergenerational responsibility, insisting that republican liberty is impossible on a degraded planet.To connect these frameworks, the article mobilizes new materialismespecially Barad's notion of intra-action-to reconceive agency as distributed across socio-ecological assemblages.Building on this ontology, it proposes an ecological republic in which nonhuman interests can be represented through guardianship models, rights-of-nature jurisprudence, and deliberative institutions informed by environmental sensing and carefully governed AI decision-support.The analysis addresses feasibility worries and the charge that posthuman inclusion dilutes human accountability, arguing instead for a republican ethics of stewardship that strengthens civic responsibility.The synthesis concludes by outlining a participatory, adaptive research agenda for sustainable and just governance.

This study aimed to clarify how elementary school students’ programming performance could be affected by scaffolding types, and how high and low working memory students profited from the intervention. The impact of different scaffolding types was empirically scrutinized with four conditions: cognitive scaffolding, metacognitive scaffolding, a combination of cognitive and metacognitive scaffolding (mixed), or no scaffolding. Students were classified into high and low working memory subjects based on their performance on the working memory test. Two-way MANCOVA results demonstrated that, compared to non-scaffolding instruction, scaffolding had a significantly superior impact on programming knowledge but not on programming skills. The mixed scaffolding group did not show significantly better scores for programming knowledge and skills than the cognitive or metacognitive scaffolding groups. Likewise, no significant difference was found between the metacognitive and cognitive scaffolding groups in programming knowledge and skills. Furthermore, interaction effects were found between scaffolding type and working memory on programming knowledge. High working memory students benefited more from the mixed scaffolding and metacognitive scaffolding. This study offers insightful suggestions for the design and development of different scaffolds to enhance programming instruction for diverse learners, especially learners with different working memory levels.

Abstract Social presence has been hypothesized to facilitate successful learning in digital and online learning environments. Instructor presence in instructional videos is suggested to enhance learners' social presence. However, research is still relatively rare regarding the elementary school learner population. The current experimental study investigated whether embedding an animated human‐like artificial pedagogical agent in an instructional video compared to having only a voice could evoke a sense of social presence and improve learning in a sample of primary school learners. The study confirmed that a sense of social presence of a virtual instructor can be fostered through a digital animated pedagogical agent; however, there was no effect on learning performance, nor did social presence mediate a relationship between learning with a pedagogical agent and learning performance.

A total of 541 elderly women aged 60-95 years (mean age: 79.87 ± 6.64) participated in the study. Physical function was assessed using HGS, 10 m walk test, figure-of-8 walk test, and 30-s chair stand test. Among the participants, 400 (76.8%) were classified as obese, and 137 (26.3%) had sarcopenia. Results showed that HGS was significantly lower in the sarcopenic group (16.58 ± 2.86 kg) than in the normal group (24.31 ± 3.33 kg, p < 0.001). HGS was negatively correlated with body fat (r = -0.146, p = 0.001) and positively correlated with physical performance. Additionally, exercise habits were significantly associated with reduced obesity risk (OR = 0.592, p = 0.027). This study was approved by the Institutional Review Board of Chonnam National University (IRB No. 1040198-220210-BR-009-03). The significance of hand grip strength was comparable to that of gait speed, walking capacity, coordination, and balance function. These findings suggest that grip strength can serve as a physical indicator of healthy condition and physical function with or without sarcopenia or obesity in older women.

Given the increasing interest in automated item generation in the second language assessment field, this study investigated the potential of two automated item generators for L2 reading assessment. The first generator, KR-Item-Generator, was developed by the authors, who used a free chatbot builder. The second, Q-Craft, was developed using GPT-4 API and employs an all-in-one method to generate questions and passages. A total of 83 pre-service teachers at a college of education in South Korea were asked to generate English reading passages and test items using both generators. They were then given a post-task survey on varying aspects of the two generators. The results of the study demonstrated that both generators were positively perceived regarding the naturalness of the sentences in the passages and the level of completion of the test items, although Q-Craft was rated significantly more positively in terms of the latter. Given these findings, we discuss the pedagogical implications and offer key directives for further L2 AIG research.

This study introduces the concept of “transboundary learning culture” as one of the important concepts to better understand students’ contemporary learning both in the East and West. Not solely relying on public schooling, schooling students employ shadow education for their academic success, which is an emerging global educational phenomenon. Based on fieldwork and qualitative data analysis through Korean shadow education practices, the authors propose the concept of “transboundary learning culture” to characterize such a new emerging trend in students’ learning practices and explain four forms of such new learning, namely (1) complex learning spaces; (2) consilience of learning materials; (3) fusion of the concepts of a good learner and (4) coexistence of the two paths for academic success. It is expected that reading the concept and considering students’ learning practices from the concept will enable scholars in curriculum studies, learning sciences, and the anthropology of learning.

A technique has recently been developed for tracking short-term spectral variations in Galactic cosmic rays (GCRs) using data from a single neutron monitor (NM), by collecting histograms of the time delay between successive neutron counts and extracting the leader fraction $L$ as a proxy of the spectral index. Here we analyze $L$ from four Antarctic NMs during 2015 March to 2023 September. We have calibrated $L$ from the South Pole NM with respect to a daily spectral index determined from published data of GCR proton fluxes during 2015--2019 from the Alpha Magnetic Spectrometer (AMS-02) aboard the International Space Station. Our results demonstrate a robust correlation between the leader fraction and the spectral index fit over the rigidity range 2.97--16.6 GV for AMS-02 data, with uncertainty 0.018 in the daily spectral index as inferred from $L$. In addition to the 11-year solar activity cycle, a wavelet analysis confirms a 27-day periodicity in the GCR flux and spectral index corresponding to solar rotation, especially near sunspot minimum, while the flux occasionally exhibited a strong harmonic at 13.5 days, and that the magnetic field component along a nominal Parker spiral (i.e., the magnetic sector structure) is a strong determinant of such spectral and flux variations, with the solar wind speed exerting an additional, nearly rigidity-independent influence on flux variations. Our investigation affirms the capability of ground-based NM stations to accurately and continuously monitor cosmic ray spectral variations in the long-term future.