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Preservice Secondary Teachers’ Mathematical Knowledge for Teaching: Focus on Reflective Practice
No full textMathematics education researchers have highlighted that preservice secondary mathematics teachers (PSTs) need opportunities to learn how their content knowledge is contextualized during instruction. Mathematical Knowledge for Teaching (MKT) subdomains provide a way to understand mathematics discipline-specific knowledge that is unique to the profession of teaching. Using a single case study design, we investigated how 11 secondary PSTs described MKT subdomains as they engaged in approximations of practice in the form of lesson planning, peer teaching, and associated guided reflections. The findings demonstrated that the PSTs referenced the MKT subdomains related to planned teacher actions (e.g., posing scripted questions) in their initial reflections. As they progressed through the approximations of practice and associated reflections, they began reflecting on MKT subdomains related to contingency actions and decisions (e.g., modifying mathematical tasks based on students’ thinking). Findings also demonstrated that, after experiences reflecting, the PSTs described a broader set of MKT subdomains (e.g., curricular trajectory) in addition to their responses to the specific prompts. We argue that providing PSTs with opportunities to reflect on their practices through the lens of MKT is an effective way to develop their understanding of how content knowledge is contextualized during mathematics teaching
Exploring transfer learning for deep learning polyp detection in colonoscopy images using YOLOv8
No full textDeep learning methods have demonstrated strong performance in object detection tasks; however, their ability to learn domain-specific applications with limited training data remains a significant challenge. Transfer learning techniques address this issue by leveraging knowledge from pre-training on related datasets, enabling faster and more efficient learning for new tasks. Finding the right dataset for pre-training can play a critical role in determining the success of transfer learning and overall model performance. In this paper, we investigate the impact of pre-training a YOLOv8n model on seven distinct datasets, evaluating their effectiveness when transferred to the task of polyp detection. We compare whether large, general-purpose datasets with diverse objects outperform niche datasets with characteristics similar to polyps. In addition, we assess the influence of the size of the dataset on the efficacy of transfer learning. Experiments on the polyp datasets show that models pre-trained on relevant datasets consistently outperform those trained from scratch, highlighting the benefit of pre-training on datasets with shared domain-specific features
Divergent DNA methylation dynamics in marsupial and eutherian embryos
No full textBased on seminal work in placental species (eutherians)1,2,3,4,5,6,7,8,9,10, a paradigm of mammalian development has emerged wherein the genome-wide erasure of parental DNA methylation is required for embryogenesis. Whether such DNA methylation reprogramming is, in fact, conserved in other mammals is unknown. Here, to resolve this point, we generated base-resolution DNA methylation maps in gametes, embryos and adult tissues of a marsupial, the opossum Monodelphis domestica, revealing variations from the eutherian-derived model. The difference in DNA methylation level between oocytes and sperm is less pronounced than that in eutherians. Furthermore, unlike the genome of eutherians, that of the opossum remains hypermethylated during the cleavage stages. In the blastocyst, DNA demethylation is transient and modest in the epiblast. However, it is sustained in the trophectoderm, suggesting an evolutionarily conserved function for DNA hypomethylation in the mammalian placenta. Furthermore, unlike that in eutherians, the inactive X chromosome becomes globally DNA hypomethylated during embryogenesis. We identify gamete differentially methylated regions that exhibit distinct fates in the embryo, with some transient, and others retained and that represent candidate imprinted loci. We also reveal a possible mechanism for imprinted X inactivation, through maternal DNA methylation of the Xist-like noncoding RNA RSX11. We conclude that the evolutionarily divergent eutherians and marsupials use DNA demethylation differently during embryogenesis
Leveraging an Arts-Based Approach to Foster Engagement, Nurture Kindness, and Prevent Violence
No full textDrawing from the insights of community partners, this study explored the roles and benefits of arts-based approaches to foster civic learning, critical media literacy, and community engagement. It also uncovered approaches to promote kindness, prevent violence, and combat online extremism, offering insights into strategies that may enhance community engagement and create a positive impact. We presented our model framework, a detailed case study of our project, and qualitative methods incorporating 15 interviews with our community partners to capture a broad range of perspectives and experiences. Interviewees were community partners who collaborated with our project in organizing events and activities using an arts-based approach to promote kindness, awareness, and violence prevention since the inception of the project. Data were analyzed using thematic data analysis. We categorized the community partners’ responses into four key themes: (1) the inherent benefits of the arts, (2) promoting kindness and preventing violence through artistic expression, (3) teaching civic responsibility through the arts, and (4) practical strategies for collaborating with community partners. The practice implications and lessons learned were discussed
Exploration of the Traffic Safety of Battery Electric Vehicles: A Case Study of Tesla Vehicle-Involved Crashes in Pennsylvania, USA
No full textAfter decades of efforts, the number of battery electric vehicles (BEV) has increased greatly around the world. Meanwhile, their unique technical features also bring many new traffic safety challenges. Using traffic crash data from Pennsylvania from 2018 to 2021, this study aims to identify characteristics and trends of BEV crashes by comparing those crashes involving Tesla vehicles (the premier BEV brand in the auto market of the United States) with crashes involving internal combustion engine vehicles (ICEV). First, Tesla and ICEV crashes are compared for crash severity, collision type, spatial and temporal distributions, and environmental features. Tesla crashes show no significant difference from those of ICEVs in severity, but they have many more rear-end and angle collisions. In addition, Tesla crashes are found to concentrate in peak hours and around noon, occurring mainly in urban areas, at intersections, and on state roads. A logistic regression model is then built to identify the important factors influencing the severity of Tesla crashes. The findings are expected to provide new insights which will help researchers understand better traffic safety issues around BEVs
The Impact of Cultural Dimensions and Quality of Life on Smartphone Addiction and Employee Performance: The Moderating Role of Quality of Life
Full text linkSmartphones, while ubiquitous and beneficial, can lead to problematic use. This study investigates the intricate interplay between cultural dimensions, smartphone addiction, and employee performance. Through the lens of distraction theory, attachment Theory, coping theory combined with Hofstede\u27s cultural dimensions, and self-regulation theory and quality of life, we examine how collectivism, individualism, uncertainty avoidance, and masculinity cultural dimensions influence smartphone addiction and its subsequent effect on employee performance. The findings, based on data collected from 233 employees at a major medical center in the Midwest region of the USA and employing structural equation modeling, reveal a significant cultural influence on smartphone addiction, ultimately leading to a decline in performance. However, quality of life emerges as a crucial moderator, mitigating the negative impact of smartphone addiction. This research offers valuable insights for information systems scholars, highlighting the importance of cultural context in understanding smartphone addiction. Furthermore, the study equips managers with practical knowledge to address smartphone addiction within a culturally diverse workforce. By implementing strategies that enhance employee quality of life, organizations can foster a more productive and engaged work environment
Using Electro-peroxone Process to Remediate Soil Contaminated with Phenol
Full text linkIndustrial processes are among human activities that cause production of a large volume of wastewater containing organic pollutants such as phenol and its derivatives. Soil remediation is crucial for enhancing environmental quality for both humans and other living organisms. This study investigate the use of an electro-peroxone system to remove environmental pollutants from soil. In conjunction with ozonation, the study employed electrochemically generated hydrogen peroxide using a carbon electrode, addressing concerns about transportation and storage. Experiments were structured using response surface methodology (RSM) with three variables: ozone dosages ranging from 4 to 8 l/h, initial pollutant concentrations from 20 to 50 mg/kg, and treatment durations between 7 and 14 days. The effectiveness of phenol removal from soil was assessed by applying a consistent voltage of 2 V/cm to the soil samples in all experiments. Results revealed a negative correlation between initial pollutant concentration and ozone consumption and a positive correlation between treatment duration and pollutant removal efficiency. Optimal removal efficiency occurred with a 14-day treatment duration, an 8 l/h ozone dosage, and a 20 mg/kg initial pollutant concentration. The electro-peroxone system\u27s application indicates its potential as a sustainable, eco-friendly, and cost-effective approach to soil remediation for pollution
Toward Sustainability: A New Construction Method for Electrically Heated Rigid Pavement Systems
Full text linkDamage caused by snow and ice to airport pavements in colder regions of the United States presents a persistent and economically significant challenge. This research explores an innovative construction method using an electrically conductive composite (ECC) composed of waterborne polyurethane and graphite powder (Gp). The ECC is applied to a Portland cement concrete substrate through a parallel stripe technique, using two types of “exposed” specimen. The study thoroughly examines the resistive heating performance of these specimens under various conditions, focusing on critical factors such as Gp concentrations in ECC, stripe thickness, spacing, and applied voltages. ECC was prepared with varying Gp concentrations (17.5% to 25%), and applied in strips of different thicknesses (1 mm, 2 mm, and 3 mm), with spacings of 15 cm and 20 cm. The specimens were subjected to alternating current voltages of 40, 50, and 60 V to measure surface heating performance. Tests were performed at room temperature (23.6°C) and a controlled sub-freezing temperature (−17°C), monitoring the surface temperature over 60 min to evaluate heating capacity and distribution. The time required for the specimens’ surface temperature to rise from −17°C to 0°C was recorded. Results indicated that ECC with 22.5% Gp content was the most effective, with exposed specimens showing a surface temperature increase of 19.94°C/h and sandwiched specimens showing 15.46°C/h. These findings suggest a promising sustainable alternative to traditional pavement heating methods, offering a viable and enduring solution for winter weather challenges on airport runways