Assigned group work is associated with increased student motivation and perceptions of belonging in an asynchronous online physiology laboratory course.

With the rise of online instruction, a better understanding of the factors that contribute to belonging and motivation in these contexts is essential to creating optimal learning environments. Although group work is known to be beneficial to student success, few studies have investigated its role in the context of asynchronous online courses. The present study addresses this gap through a survey of 146 undergraduate students in an asynchronous online physiology lab over two semesters, one with required group work and one without group work. Students were surveyed to evaluate the influence of group work on their motivation and sense of belonging, as well as their perceptions of inclusive and exclusive features of the course. Students assigned to groups had a higher sense of belonging (P = 0.006) and beliefs about their competence (P = 0.002) and perceived lower effort and psychological costs associated with the course (P = 0.04 and 0.04, respectively) compared to students not assigned to groups. Students assigned to groups reported that peer interactions made them feel included in the course (70% of coded responses) while those not assigned to groups valued instructor interactions (51% of coded responses) as inclusive. Negative peer interactions were commonly reported as exclusive by students assigned to groups (28% of coded responses) while a lack of peer interactions (23% of coded responses) made students not assigned to groups feel excluded. These data indicate that assigning groups in asynchronous online courses is an effective way to increase student motivation and perceptions of belonging.NEW & NOTEWORTHY This study explores the effect of assigned group work in an asynchronous online physiology laboratory course on student motivation and belonging. Students' perceptions of belonging and competence-related beliefs were higher, and effort and psychological costs were lower, when assigned to groups compared to students not assigned to groups. Students assigned to groups noted peer interactions as the most inclusive aspect of the course, whereas instructor interactions were noted as inclusive by those not assigned group work.

"They helped me through the semester": electronic instructor messages can foster the instructor-student relationship.

Building rapport between instructors and students is a challenge, especially in large classes and in online environments. Previous work has shown that non-content Instructor Talk can foster positive student-teacher relationships, but less is known about non-content talk in electronic instructor messages. Here, we used the established Instructor Talk framework to craft positively phrased electronic messages that were sent through the course's learning management system to students enrolled in an introductory biology course at a large public institution. We examined both close- and open-ended survey responses (n = 226) to assess students' perceptions of the electronic messages, the course, and their instructor. Of the established Instructor Talk categories, the building student/instructor relationship category was most memorable to students. Encouragingly, 61% of students indicated they "liked the course more" and 88% indicated they "liked the instructor more" in response to the electronic messages. This demonstrates that implementing positively phrased Instructor Talk into electronic communication is an effective way to build rapport between instructors and students.

Persistent Miscalibration for Low and High Achievers despite Practice Test Feedback in an Introductory Biology Course.

Students' ability to accurately judge their knowledge is crucial for effective learning. However, students' perception of their current knowledge is often misaligned with their actual performance. The relationship between learners' perception of their performance and their actual performance on a task is defined as calibration. Previous studies have shown significant student miscalibration in an introductory biology course: students' predicted exam scores were, on average, significantly higher than their actual scores. The goal of this study was to determine whether completion of a practice test before exams would result in better performance and calibration. The hypothesis was that students who completed a practice test would perform better and be better predictors of their performance on exams than students who did not engage in practice testing. As predicted, students who voluntarily completed a practice test, on average, performed better and were more calibrated than students who did not. Importantly, however, many of the lowest-performing students continued to significantly overestimate their knowledge, predicting higher scores on the exam than they actually earned, despite feedback from practice tests. In contrast, practice testing was associated with underconfidence in high-performing students. These findings indicate that practice tests may enhance calibration for many students. However, additional interventions may be required for the lowest-performing students to become better predictors of their performance.

Opportunities for Self-Evaluation Increase Student Calibration in an Introductory Biology Course.

Accurate self-evaluation is critical for learning. Calibration describes the relationship between learners' perception of their performance and their actual performance on a task. Here, we describe two studies aimed at assessing and improving student calibration in a first-semester introductory biology course at a 4-year public institution. Study 1 investigated students' (n = 310) calibration (the difference between estimated and actual exam performance) across one semester. Students were significantly miscalibrated for the first exam: their predicted scores were, on average, significantly higher than their actual scores. The lowest-performing students had the most inaccurate estimates. Calibration improved with each exam. By the final exam, students underestimated their scores. We initiated a second study in the following semester to examine whether explicitly teaching students about self-evaluation strategies would improve their calibration and performance. Instruction in the experimental section (n = 290) focused on students' tendency to overestimate their abilities and provided retrieval-practice opportunities. Students in the experimental section showed better calibration and performance on the first exam compared with students in a control section taught by a different instructor during the same semester (n = 251). These findings suggest that simple instructional strategies can increase students' metacognitive awareness and improve their performance.

Phylogeography of the Mekong mud snake (Enhydris subtaeniata): the biogeographic importance of dynamic river drainages and fluctuating sea levels for semiaquatic taxa in Indochina.

During the Cenozoic, Southeast Asia was profoundly affected by plate tectonic events, dynamic river systems, fluctuating sea levels, shifting coastlines, and climatic variation, which have influenced the ecological and evolutionary trajectories of the Southeast Asian flora and fauna. We examined the role of these paleogeographic factors on shaping phylogeographic patterns focusing on a species of semiaquatic snake, Enhydris subtaeniata (Serpentes: Homalopsidae) using sequence data from three mitochondrial fragments (cytochrome b, ND4, and ATPase-2785 bp). We sampled E. subtaeniata from seven locations in three river drainage basins that encompassed most of this species' range. Genetic diversities were typically low within locations but high across locations. Moreover, each location had a unique suite of haplotypes not shared among locations, and pairwise φ(ST) values (0.713-0.998) were highly significant between all location pairs. Relationships among phylogroups were well resolved and analysis of molecular variance (AMOVA) revealed strong geographical partitioning of genetic variance among the three river drainage basins surveyed. The genetic differences observed among the populations of E. subtaeniata were likely shaped by the Quaternary landscapes of Indochina and the Sunda Shelf. Historically, the middle and lower Mekong consisted of strongly dissected river valleys separated by low mountain ranges and much of the Sunda Shelf consisted of lowland river valleys that served to connect faunas associated with major regional rivers. It is thus likely that the contemporary genetic patterns observed among populations of E. subtaeniata are the result of their histories in a complex terrain that created abundant opportunities for genetic isolation and divergence yet also provided lowland connections across now drowned river valleys.

Chromosome end maintenance by telomerase.

Telomeres, protein-DNA complexes at the ends of eukaryotic linear chromosomes, are essential for genome stability. The accumulation of chromosomal abnormalities in the absence of proper telomere function is implicated in human aging and cancer. Repetitive telomeric sequences are maintained by telomerase, a ribonucleoprotein complex containing a reverse transcriptase subunit, a template RNA, and accessory components. Telomere elongation is regulated at multiple levels, including assembly of the telomerase holoenzyme, recruitment of telomerase to the chromosome terminus, and telomere accessibility. This minireview provides an overview of telomerase structure, function, and regulation and the role of telomerase in human disease.

Proteasome-dependent degradation of Est1p regulates the cell cycle-restricted assembly of telomerase in Saccharomyces cerevisiae.

Telomerase counteracts loss of terminal sequences incurred during DNA replication. In S. cerevisiae, telomerase contains an RNA template (TLC1), a reverse transcriptase (Est2p) and at least two regulatory proteins (Est1p and Est3p). Whereas Est2p is constitutively telomere bound, Est1p associates in late S phase, coincident with telomere lengthening. Here we directly demonstrate by coimmunoprecipitation that the composition of telomerase varies during the cell cycle. The absence of Est1p and Est3p from the complex during G1 phase can be attributed to proteasome-dependent degradation of Est1p. Stabilization of Est1p during G1 phase promotes telomerase assembly, revealing a previously uncharacterized role for Est1p in the recruitment of Est3p to the telomerase complex. Though catalytically active, complexes assembled during G1 cannot lengthen telomeres. We conclude that telomerase assembly during G1 phase is regulated by Est1p stability, but assembly is insufficient to activate telomerase at telomeres.