Search Results (22,652)

This study investigates the durability of concrete structures under severe environmental conditions, focusing on the effects of thermal stress, saline exposure, and seismic activity. The research employs a dual approach, combining laboratory experiments and field case studies to analyze various environmental impacts, mix designs, and the use of crystalline admixtures. Two concrete mix designs, CMD-01-C30/37 (mass concrete) and CMD-02-C35/45 (underwater concrete), were developed and tested for strength, permeability, and self-healing properties. The results demonstrate that both mix designs met or exceeded the required strength specifications, with improved resistance to water penetration and permeability depths lower than the code requirements set by European standards from EC2. The incorporation of crystalline admixtures in the mix designs significantly enhanced durability and performance, aligning with the priority of developing zero-carbon concrete solutions. The study also observed the self-healing capabilities of concrete treated with crystalline admixtures, as evidenced by the sealing of cracks at expansion and construction joints over time. These findings contribute to the development of a robust methodology for creating resilient structures adaptable to climate change, with potential implications for enhancing seismic resistance and structural longevity. The study underscores the importance of considering environmental factors and innovative admixtures in concrete design to improve durability and resilience, particularly in areas prone to seismic activity and extreme environmental conditions. Future research directions should focus on further investigating self-healing mechanisms, exploring the integration of durable and self-healing cement-based materials in engineering practice, and evaluating applications for both new construction and retrofitting existing structures. Full article

Mixed-effects models have become indispensable tools for analyzing data in second language acquisition (SLA) research. This tutorial offers a step-by-step guide to conducting mixed-effects analyses for simple designs using the gamlj package in jamovi, a user-friendly, free statistical software. We begin by discussing the advantages of mixed-effects modeling over traditional methods, particularly for SLA data, and the rationale for focusing on simple designs. Subsequently, we introduce the gamlj package, highlighting its intuitive interface and error-prevention features. To illustrate the application of the package, we employ toy datasets that can be easily replicated and used with other statistical software. By providing a clear and accessible approach, this tutorial empowers SLA researchers to effectively analyze their data and draw meaningful conclusions. Full article

Developing efficient strategies for VOC emission abatement is an urgent task for protection of the environment and human health. Complete catalytic oxidation exhibits advantages, making it an effective, environmentally friendly, and economically profitable approach for VOC elimination. Pd-based catalysts are known as highly active for hydrocarbon catalytic oxidation. The nature of carrier materials is of particular importance because it may affect activity by changing physicochemical properties of the palladium species. In this work, Al₂O₃, CeO₂, CeO₂-Al₂O₃, and Y-doped CeO₂-Al₂O₃ were used as carriers of palladium catalysts. Methane and benzene were selected as representatives of two types of hydrocarbons. A decisive step in complete methane oxidation is the first C–H bond breaking, while the extraordinary stability of the six-membered ring structure is a challenge in benzene oxidation. The support effect was explored by textural measurements using XRF, XRD, XPS, EPR, and TPR techniques. Three ceria-containing samples showed superior CH₄ oxidation performance, achieving 90% methane conversion at about 300 °C and complete oxidation at 320 °C. Evidence for presence of Pd²⁺ species in all samples regarded as most active was provided by XP-derived analysis. Pd/Y-Ce/Al catalysts exhibited very high activity in benzene oxidation by reaching 100% conversion at 180 °C. The contributions of higher Pd and Ce³⁺ surface concentrations, the presence of O₂⁻-adsorbed superoxo species, and Pd⁰ ↔ PdO redox transfer were considered. The potential of a simple, environmentally friendly, and less energy demanding mechanochemical preparation procedure of mixed oxides was demonstrated. Full article

This study investigates user experiences of interactions with two types of robots: Pepper, a social humanoid robot, and Double 3, a self-driving telepresence robot. Conducted in a controlled setting with a specific participant group, this research aims to understand how the design and functionality of these robots influence user perception, interaction patterns, and emotional responses. The findings reveal diverse participant reactions, highlighting the importance of adaptability, effective communication, autonomy, and perceived credibility in robot design. Participants showed mixed responses to human-like emotional displays and expressed a desire for robots capable of more nuanced and reliable behaviors. Trust in robots was influenced by their perceived functionality and reliability. Despite limitations in sample size, the study provides insights into the ethical and social considerations of integrating AI in public and professional spaces, offering guidance for enhancing user-centered designs and expanding applications for social and telepresence robots in society. Full article

Fermented feed is extensively used in animal production due to their improved palatability and efficient utilization. This study aimed to explore the effects of fermented feed on growth performance and gut health, particularly through the modulation of intestinal stem cells (ISCs). Twenty-four 28-day-old male weaned piglets were randomly assigned into two groups (n = 12): piglets in a control group fed a basal diet, and an experimental group fed a basal diet replaced with 6% fermented mixed feed (FMF) for 28 days. The results indicated that FMF significantly elevated the growth rate, feed intake, and nutrient digestibility of piglets (p < 0.05). Furthermore, FMF supplementation increased the jejunal villus height, transepithelial electrical resistance (TEER) values, and the expression of tight junction proteins (ZO-1 and Claudin1) (p < 0.05). Immunohistochemistry (IHC) analysis revealed that FMF increased the number of Olfm4⁺ ISCs and PCNA⁺ mitotic cells in jejunal crypts, facilitating the differentiation of ISCs into enterocytes (Villin), goblet cells (MUC2), and enteroendocrine cells (CHGA). Conversely, the protein expression of Cleaved Caspase-3 was decreased in the FMF group (p < 0.05). Notably, the Wnt/β-catenin signaling pathway, including FZD7 and Active β-catenin, was significantly upregulated in the jejunum after FMF supplementation. Consistent with these findings, intestinal organoids derived from jejunal crypts in the FMF group demonstrated enhanced growth and increased expression of Lgr5, PCNA, KRT20, and β-catenin (p < 0.05). These results suggest that fermented feed promotes intestinal development by enhancing ISC proliferation and differentiation via activation of the Wnt/β-catenin signaling pathway. Full article

In this study, we report the synthesis of amphiphilic hyperbranched poly[(2-dimethylaminoethyl methacrylate)-co-(benzyl methacrylate)] statistical copolymers with two different stoichiometric compositions using the reversible addition–fragmentation chain transfer polymerization (RAFT) technique. The selection of monomers was made to incorporate a pH and thermoresponsive polyelectrolyte (DMAEMA) component and a hydrophobic component (BzMA) to achieve amphiphilicity and study the effects of architecture and environmental factors on the behavior of the novel branched copolymers. Molecular characterization was performed through size exclusion chromatography (SEC) and spectroscopic characterization techniques (¹H-NMR and FT-IR). The self-assembly behavior of the hyperbranched copolymers in aqueous media, in response to variations in pH, temperature, and ionic strength, was studied using dynamic light scattering (DLS), electrophoretic light scattering (ELS), and fluorescence spectroscopy (FS). Finally, the efficacy of the two novel copolymers to encapsulate curcumin (CUR), a hydrophobic, polyphenolic drug with proven anti-inflammatory and fluorescence properties, was established. Its encapsulation was evaluated through DLS, UV–Vis, and fluorescence measurements, investigating the change of hydrodynamic radius of the produced mixed copolymer–CUR nanoparticles in each case and their fluorescence emission properties. Full article

Using digital and non-digital card games to teach mathematics is a well-established didactic technique widely applied at different levels of education. Game-based learning strategies are also gaining ground in higher education, but the use of maths card games in university settings remains limited. Generation Z students are true digital natives, members of a hyper-cognitive generation with a learning profile different from any previous generation. In this paper, an original non-digital card game, Blue Yeti, is presented that supports determining the convergence property of improper integrals using the comparison theorems and the Cauchy–Maclaurin test, providing a motivational and effective way of acquiring knowledge for Gen Z students. This paper provides a comprehensive overview of the development process, rules, and gameplay mechanics of Blue Yeti, which was created as a key component of a multifunctional didactic framework. In addition, it presents findings from a two-year research study conducted among first-year bachelor’s students in computer science on the benefits of playing Blue Yeti. Quantitative studies were carried out with 63 first-year IT students using a quasi-experimental research design to measure the effectiveness of the game. A pre- and post-test design was used with the experimental group of 31 participants to evaluate the short-term effects of card game-based learning. A t-test for paired samples was used for hypothesis testing. To assess the medium-term impact, the results from the related midterm exam problems were statistically analysed, comparing the outcomes of the experimental group with those of the control group using the Mann–Whitney U-test. The results indicated that the experimental group outperformed the control group, achieving a mean score of 3.03 out of 6 on the designated midterm exam problems, compared to the control group’s mean score of 1.78. Additionally, student attitudes towards the game were measured using a mixed-method approach, which provided not only quantitative data but also qualitative information on student attitudes towards Blue Yeti, complementing the statistics on learning outcomes. The results of the study clearly support the effectiveness of the card game. Full article

During the Middle-to-Late Neolithic period (7000–3800 BP), Shaanxi Province served as a critical juncture in the transmission of crops. Foxtail millet (Setaria italica), broomcorn millet (Panicum miliaceum), and rice (Oryza sativa) spread westwards into the Gansu–Qinghai region and southwards into the Sichuan basin, whilst wheat (Triticum aestivum) and barley (Hordeum vulgare) were transmitted through the Shaanxi region to the middle and lower Yellow River regions. Neolithic settlements are found in all three of the main geomorphic settings in Shaanxi: the Loess Plateau, plains, and mountainous areas. While the extent to which crop diffusion and distribution were influenced by environmental changes has previously been highlighted, the strategies of crop utilization in different geomorphic contexts have not been specified. Based on crop-remains data from 33 archaeological sites in Shaanxi, this study uses statistical modeling and ArcGIS-based spatial analysis to investigate prehistoric crop utilization in Shaanxi during the Neolithic period and its environmental determinants. Our results indicate the following: (1) The dominant crops in the Neolithic Shaanxi were foxtail millet and broomcorn millet, with the proportion of foxtail millet increasing over time. (2) The Guanzhong Plain was the earliest region in Shaanxi to adopt millet and rice (~7000–3800 BP). Subsequently, millet and rice had influenced the Qinba Mountains by ~5000 BP at the latest. By ~3800 BP, millet had affected the entire northern Shaanxi Plateau, with rice only found at the Shimao site around 4000 BP. Finally, wheat and barley influenced the Guanzhong region and the Qinba region in Shaanxi around 4000 BP. In addition, rice, wheat, and barley mainly enhanced agricultural diversity in the Guanzhong Plain and Qinba Mountains but had limited impact in the Northern Plateau, where cattle and sheep have enriched subsistence strategies since about 4500 BP. (3) Environmental factors affected the distribution of crops to different extents—elevation and river proximity had minimal effects on foxtail millet and broomcorn millet but significantly influenced the presence of rice, wheat, and barley. These factors led to a spatial pattern where millet dominated in the Northern Plateau, while the Guanzhong Plain and Qinba Mountains developed mixed farming systems incorporating all four seed types. This study provides new insights into the environmental mechanisms influencing crop diffusion and prehistoric human adaptation during the Neolithic period in Shaanxi. Full article

In the fire-prone tropical savanna landscapes of northern South America, forest edge effects significantly shape tree structural integrity and functional traits, with implications for ecosystem resilience, carbon storage, and biodiversity. This study examines how the edge effect, intensified by fire, affects species dominance, forest structure, and functional trait distributions in this region. Using non-metric multidimensional scaling (NMDS) and generalized additive mixed models (GAMMs), we analyzed changes in species abundance and structural variables (biomass, basal area, tree height, and wood density), as well as leaf (leaf thickness, leaf moisture, leaf dry matter content (LDMC), and specific leaf area (SLA)) and stem (bark and stem thickness and stem-specific density) traits across edge-to-interior gradients. The key findings indicate significant reductions in tree height (F = 19.27, p < 0.01), basal area (F = 6.52, p < 0.01), and biomass (F = 5.44, p < 0.01) near the edges. Leaf moisture (F = 11.8, p < 0.01) and specific leaf area (SLA, F = 7.02, p < 0.01) increased at the edges, reflecting microenvironmental gradients, with heightened fire sensitivity seen in traits like bark thickness (F = 11.88, p < 0.01). Fire-affected areas displayed intensified adaptive trait shifts, suggesting a compounded resilience but potential functional convergence, limiting adaptive capacity under climate stressors. These findings emphasize the ecological significance of edge–fire interactions, advocating conservation strategies to enhance structural and trait diversity for ecosystem stability. Our study underscores the need for targeted management to bolster resilience and biodiversity within these dynamic landscapes as climate pressures intensify. Full article

Engineered cementitious composites (ECCs) are a type of high-performance composite material, but in practical applications, ECCs that combine high strength with high toughness have greater development potential. Moreover, there is currently no unified standard or method for assessing the bending toughness of ECCs. This study is based on the Modified Andreasen and Andersen model (MAA) design ratio of the closest packing theory to investigate the effect of changes in the water–binder ratio and fiber content, where the water–binder ratio is taken as 0.19, 0.22, and 0.25, and the fiber content is taken as 1.0%, 1.5%, and 2.0%, respectively, to improve the comprehensive performance of ECCs. Information about tensile strength, bending strength, tensile toughness, and bending toughness is examined. Three different ways to measure bending toughness are compared and improved; the energy factor E_ms is used to measure bending toughness, and a response surface methodology is used to design and test the best mix ratio. The results indicate that when the water–binder ratio is 0.22 and the fiber content is 1.9%, the performance is optimal. Compared with the prediction group, the measured group presented an increase in tensile strength of 2.64%, a decrease in bending strength of 3.39%, an increase in tensile toughness of 3.22%, and an increase in the energy factor E_ms of 1.21%. This finding indicates that the response surface optimization improved the performance of the ECCs in various aspects. Full article

Understanding the factors that influence teacher well-being is crucial as it significantly affects students, teachers, schools, and the sustainability of the education system, especially during prolonged emergencies. This study contributes to the field by empirically testing a conceptual model of teacher well-being in emergency contexts, specifically addressing the COVID-19 school closures with a sample of over 19,600 teachers from Kazakhstan through an online survey design. Utilising a multidimensional socio-ecological framework that considers individual, school and home, community, and national factors, this study identifies key predictors of teacher self-reported well-being. Individual-level predictors explained 9.3% of the variation in physical well-being (F = 118, p < 0.001, R² = 0.093) and 4.5% in psychological well-being (F = 72.2, p < 0.001, R² = 0.045). In contrast, school- and home-level predictors demonstrated significantly greater explanatory power, accounting for 21.9% (F = 128, p < 0.001, R² = 0.219) and 15.5% (F = 89.5, p < 0.001, R² = 0.155) of the variation in physical and psychological well-being, respectively. Community-level predictors explained 12.8% of the variation in physical well-being (F = 191, p < 0.001, R² = 0.128) and 10.2% in psychological well-being (F = 324, p < 0.001, R² = 0.102), while national-level predictors accounted for much smaller proportions: 0.67% for physical well-being (F = 21.8, p < 0.001, R² = 0.0067) and 1.4% for psychological well-being (F = 83.589, p < 0.001, R² = 0.014). These findings highlight the significant influence of home and school, as well as community-level predictors, on teacher well-being during emergency contexts, suggesting that interventions targeting these areas may be particularly effective in supporting teacher well-being. The findings reveal that while Kazakhstani teachers reported poor physical well-being, they generally had a more positive assessment of their psychological well-being. Vulnerable groups included women, older teachers, non-Kazakh teachers, and those with higher education levels, as well as teachers in Russian medium and mixed-medium schools, all of whom reported lower physical and psychological well-being. Additional risk factors identified were a lack of student engagement, difficult relationships with parents, a directive leadership style, family conflicts, and inadequate resources at home and school. Conversely, protective factors such as teacher autonomy, collegiality, networking opportunities, and self-efficacy emerged as significant contributors to well-being. These findings reveal a complex interplay between cultural factors and subjective perceptions of well-being. This study emphasises the critical role of these predictors in both emergency and non-emergency contexts, underscoring the urgent need for targeted policies and programmes that sustainably support and enhance teacher well-being holistically. This approach will promote Sustainable Development Goal (SDG) 3 (well-being) and ensure access to equitable quality education (SDG 4) for all learners, ultimately contributing to the overall resilience of educational systems. Full article

At the turn of the 20th century, Christian and Catholic churches in Western nations established numerous mission hospitals in non-European regions. In China, mission hospitals represent a significant category of modern architectural heritage, symbolising advancements in healthcare and medical education while also serving as historical artifacts of early cultural interactions between China and the West. With ongoing developments in medical technology, these mission hospital structures no longer meet contemporary healthcare demands; many have been repurposed or temporarily abandoned. Preserving and effectively repurposing mission hospital heritage has thus emerged as a critical issue. In the present study, the Shantung Christian University Union Medical College was examined as a case study in addressing this challenge. The site retains the original Outpatient Building, Inpatient Building, Medical Teaching Building, and other architectural heritage and has preserved the original mixed Chinese and Western architectural styles. A combination of historical research, field investigation, and historic layering was adopted in the present study, drawing primarily on data from historical maps, satellite images from different periods, aerial photography from drones, architectural drawings, and other relevant historical data. Through case studies, methods for characterising and identifying the landscape and architectural heritage of mission hospitals were explored. Principles for the preservation and regeneration of the heritage of church hospitals were also proposed, with a view to providing a reference for the study and preservation of this type of heritage. Full article

This study aimed to evaluate the shear bond strengths of six self-adhesive resin cements (SACs) on porcelain surfaces and to compare the effectiveness with and without silane application. One hundred and twenty feldspathic porcelain specimens were prepared, etched with 9.5% HF, and divided into two main groups: (i) without silane, and (ii) with silane application. Each main group was further divided into six subgroups, testing six various SACs. Shear bond strength was measured using a universal testing machine, and the de-bonded surfaces were examined with a stereomicroscope. The statistical analysis was tested with two-way ANOVA and post hoc with Tukey’s. The results showed that Panavia SA Luting Multi had the highest shear bond strength, especially with silane application, while G-Cem One exhibited the lowest in the absence of silane. The addition of silane application significantly improved the shear bond strengths of G-Cem One, Panavia SA Luting Multi, and RelyX Unicem compared to situations without silane application. The adhesive and mixed failure modes were found to depend on the brand of SACs. No cohesive failure was detected. The study concludes that Panavia SA Luting Multi achieves superior shear bond strength on feldspathic porcelain when used with a separate silane agent. The etched feldspathic porcelain surface primed with silane coupling agent is recommended for optimal bond strength when using with SACs such as G-Cem One, Panavia SA Luting Multi, or RelyX Unicem. Full article

Background: The purpose of this study was to assess hydration status via saliva osmolarity throughout a 12-week Fire School in recruit firefighters. Methods: At the beginning (AM) and end (PM) of the workday for 13 weeks (a 12-week Fire School and an additional transition week), saliva osmolarity was measured, recorded, and relayed to each participant in the sample, which included 23 recruit firefighters. The average weekly osmolarity scores were computed for AM and PM. Separate linear mixed-effects models were used to assess the changes in osmolarity at each time of day over the course of the training. Bonferroni-adjusted post hoc tests were used to identify significant differences between weeks while maintaining test-wise error (α = 0.05). Results: AM was significantly lower in week 12 than in weeks 4 and 6, and lower in week 13 than in weeks 2, 4, 6, and 7 (p ≤ 0.035 for all). PM was significantly lower in week 12 than in weeks 3 and 7, and was lower in week 13 than in weeks 1, 3, and 7 (p ≤ 0.019 for all). Conclusion: This study demonstrated that hydration status via saliva osmolarity improved during the last half of Fire School despite those weeks being more physically and thermally challenging. Full article

The accurate description of excited states is crucial for the development of electronic structure theory. In addition to determining excitation energies, strong state interactions arise when electronic states with the same symmetry are degenerate or nearly degenerate, often requiring a multi-state treatment. These strong correlation effects and state interactions can be effectively handled by the Hamiltonian matrix correction-based density functional valence bond (hc-DFVB) method, a multi-reference density functional theory capable of accurately describing electronic state interactions. In this paper, we explore the low-lying excited states of four isoelectronic systems (C₂H, CN, CO⁺, BO) using valence bond methods, including the valence bond self-consistent field (VBSCF) and hc-DFVB methods. Our results show that the hc-DFVB method provides significantly better excitation energies compared to VBSCF. Furthermore, hc-DFVB can reliably predict the correct ordering of excited states, whereas VBSCF shows some ordering inconsistencies. By categorizing the VB structures into groups based on point group symmetry, we can extract the key structural contributions and bonding pictures of each state from the weight distribution of these groups. Additionally, we study the potential energy curves for lithium fluoride (LiF) and a mixed-valence spiro cation, demonstrating the superior performance of hc-DFVB when applied to the study of near-degenerate excited states in the avoided crossing region. Full article