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Historically, physics education primarily consisted of lectures in which students have a largely passive role. Proponents of educational reform have rallied around active learning to increase engagement and retention in STEM fields, particularly advocating peer interactions to build a foundation of deep understanding. However, little is known about how students' prior preparation for introductory courses impacts their mastery of course material when instructors incorporate active learning. In the present study, we examine learning outcomes in two sections of an introductory mechanics course at an institution with a wide range of students' prior mathematics preparation as assessed by quantitative SAT scores. For each of three years, one section was taught using peer instruction in which much of the class time was spent in small-group discussions between students. The other section was taught by the same instructor using interactive lectures in which discussions primarily took place between volunteers from the class and the instructor. We find that students enrolled in the peer instruction sections earned lower grades in the course than did students in the interactive sections. We also find students in the peer instruction sections with lower quantitative SAT scores showed lower gains in understanding foundational concepts as assessed by the Force Concept Inventory and were less likely to earn an A in the course than comparable students in the interactive sections. While further research is needed to confirm these results, this study suggests that peer instruction might not be the optimal pedagogy for heterogeneous populations. 

Abstract Evidence of fluctuations in transport have long been predicted in³He. They are expected to contribute only within 100μK ofT_cand play a vital role in the theoretical modeling of ordering; they encode details about the Fermi liquid parameters, pairing symmetry, and scattering phase shifts. It is expected that they will be of crucial importance for transport probes of the topologically nontrivial features of superfluid³He under strong confinement. Here we characterize the temperature and pressure dependence of the fluctuation signature, by monitoring the quality factor of a quartz tuning fork oscillator. We have observed a fluctuation-driven reduction in the viscosity of bulk³He, finding data collapse consistent with the predicted theoretical behavior. 

Abstract Catastrophic events, such as volcanic eruptions, can have profound impacts on the demographic histories of resident taxa. Due to its presumed effect on biodiversity, the Pleistocene eruption of super‐volcano Toba has received abundant attention. We test the effects of the Toba eruption on the diversification, genetic diversity, and demography of three co‐distributed species of parachuting frogs (GenusRhacophorus) on Sumatra. We generate target‐capture data (~950 loci and ~440,000 bp) for three species of parachuting frogs and use these data paired with previously generated double digest restriction‐site associated DNA (ddRADseq) data to estimate population structure and genetic diversity, to test for population size changes using demographic modelling, and to estimate the temporal clustering of size change events using a full‐likelihood Bayesian method. We find that populations around Toba exhibit reduced genetic diversity compared with southern populations, and that northern populations exhibit a shift in effective population size around the time of the eruption (~80 kya). However, we infer a stronger signal of expansion in southern populations around ~400 kya, and at least two of the northern populations may have also expanded at this time. Taken together, these findings suggest that the Toba eruption precipitated population declines in northern populations, but that the demographic history of these three species was also strongly impacted by mid‐Pleistocene forest expansion during glacial periods. We propose local rather than regional effects of the Toba eruption, and emphasize the dynamic nature of diversification on the Sunda Shelf.