Demonstration of allelopathy of horseradish root extract on lettuce seed.

Allelopathy plays crucial roles in invasive plant viability and agricultural production systems. However, there is no well-established hands-on learning activity to teach the concept of allelopathy. Nor is there an activity which allows students to gain knowledge about glucosinolates and their corresponding enzyme, myrosinase, which are present in almost all Brassica crops. Lettuce germination was counted by the students from three different treatments including water treated with Parafilm sealing, horseradish treated with Parafilm sealing, and horseradish treated without Parafilm sealing. Additionally, lettuce root length was measured by students using ImageJ software from each treatment using pictures captured by students' smartphones. Students took an identical quiz as a pre-laboratory and a post-laboratory assignment. Their average scores on the pre-laboratory and post-laboratory quizzes were 3.14 and 6.56 out of 10, respectively, indicating the lab activity significantly improved students' understanding of allelopathy and glucosinolate-myrosinase system. In addition, students (n = 76) completed a survey post-laboratory to assess their self-efficacy. This simple and cost-effective laboratory activity improved students' knowledge and skill development as it made learning more inviting, meaningful, and fun. © 2019 International Union of Biochemistry and Molecular Biology, 47(3):333-340, 2019.

General Chemistry Student Attitudes and Success with Use of Online Homework: Traditional-Responsive versus Adaptive-Responsive.

We investigated whether use of an adaptive-responsive online homework system (OHS) that tailors homework to students' prior knowledge and periodically reassesses students to promote learning through practice retrieval has inherent advantages over traditional-responsive online homework. A quasi-experimental cohort control post-test-only design with nonequivalent groups and propensity scores with nearest neighbor matching (n = 6,114 pairs) was used. The adaptive system was found to increase the odds of a higher final letter grade for average, below average, and failing students. However, despite the learning advantages, students self-reported less favorable attitudes toward adaptive-responsive (3.15 of 5) relative to traditional-responsive OHS (3.31). Specific to the adaptive OHS, the following were found: (i) student attitudes were moderately and positively correlated (r = 0.36, p < 0.01) to final letter grade, (ii) most students (95%) reported engaging in remediation of incorrect responses, (iii) a majority of students (69%) reported changes in study habits, and (iv) students recognized the benefit of using adaptive OHS by ranking its assignments and explanations or review materials as two of the top three most useful course aspects contributing to perceived learning. Instructors can use our findings to inform their choice of online homework system for formative assessment of chemistry learning by weighing the benefits, disadvantages, and learning pedagogies of traditional-responsive versus adaptive-responsive systems.

Student Integration into STEM Careers and Culture: A Longitudinal Examination of Summer Faculty Mentors and Project Ownership.

It is widely recognized that the United States needs to attract and retain more people in science, technology, engineering, and mathematics (STEM) careers. Intensive undergraduate research experiences (UREs) are one of the few strategies shown to improve longitudinal student interest and persistence in STEM-related career pathways; however, less is known about the underlying process linking activities to positive outcomes. The tripartite integration model of social influences (TIMSI) provides a framework for understanding the social influence processes by which students integrate into STEM careers and culture. The current study used a longitudinal design and latent growth curve modeling to examine and predict the development of scientific research career persistence intentions over the course of an intensive summer URE. The latent growth curve analysis showed that student persistence intentions declined and rebounded over the course of the summer. Furthermore, the positive impact of faculty mentor role modeling on growth trajectories was mediated through internalization of science community values. In addition, project ownership was found to buffer students from the typical trend of declining and rebounding persistence intentions. The TIMSI framework illuminates the contextual features and underlying psychological processes that link UREs to student integration into STEM careers and culture.

Student Perceptions of Online Homework Use for Formative Assessment of Learning in Organic Chemistry.

Use of online homework as a formative assessment tool for organic chemistry coursework was examined. Student perceptions of online homework in terms of (i) its ranking relative to other course aspects, (ii) their learning of organic chemistry, and (iii) whether it improved their study habits and how students used it as a learning tool were investigated. Our students perceived the online homework as one of the more useful course aspects for learning organic chemistry content. We found a moderate and statistically significant correlation between online homework performance and final grade. Gender as a variable was ruled out since significant gender differences in overall attitude toward online homework use and course success rates were not found. Our students expressed relatively positive attitudes toward use of online homework with a majority indicating improved study habits (e.g., study in a more consistent manner). Our students used a variety of resources to remediate incorrect responses (e.g., class materials, general online materials, and help from others). However, 39% of our students admitted to guessing at times, instead of working to remediate incorrect responses. In large enrollment organic chemistry courses, online homework may act to bridge the student-instructor gap by providing students with a supportive mechanism for regulated learning of content.