The role of pedagogical tools in active learning: a case for sense-making

Evidence from the research literature indicates that both audience response systems (ARS) and guided inquiry worksheets (GIW) can lead to greater student engagement, learning, and equity in the STEM classroom. We compare the use of these two tools in large enrollment STEM courses delivered in different contexts, one in biology and one in engineering. The instructors studied utilized each of the active learning tools differently. In the biology course, ARS questions were used mainly to check in with students and assess if they were correctly interpreting and understanding worksheet questions. The engineering course presented ARS questions that afforded students the opportunity to apply learned concepts to new scenarios towards improving students conceptual understanding. In the biology course, the GIWs were primarily used in stand-alone activities, and most of the information necessary for students to answer the questions was contained within the worksheet in a context that aligned with a disciplinary model. In the engineering course, the instructor intended for students to reference their lecture notes and rely on their conceptual knowledge of fundamental principles from the previous ARS class session in order to successfully answer the GIW questions. However, while their specific implementation structures and practices differed, both instructors used these tools to build towards the same basic disciplinary thinking and sense-making processes of conceptual reasoning, quantitative reasoning, and metacognitive thinking.Comment: 20 pages, 5 figure

A Machine Learning Approach to Predicting Early and Late Reintubation

Accurate estimations of surgical risks is important for improving the shared decision making and informed consent processes. Reintubation is a severe postoperative complication that can lead to various other detrimental outcomes. Reintubation can also be broken up into early reintubation (within 72 hours of surgery) and late reintubation (within 30 days of surgery). Using clinical data provided by ACS NSQIP, scoring systems were developed for the prediction of combined, early, and late reintubation. The risk factors included in each scoring system were narrowed down from a set of 37 pre and perioperative factors. The scoring systems demonstrated good performance in terms of both accuracy and discrimination, and these results were only marginally worse than prediction using the full set of risk variables. While more work needs to be done to identify clinically relevant differences between the early and late reintubation outcomes, the scoring systems provided here can be used by surgeons and patients to improve the quality of care overall

Hydrogenated and deuterated iron clusters: Infrared spectra and density functional calculations

Iron clusters react sequentially with hydrogen molecules to form multiply hydrogenated products. The increases in cluster ionization potential upon reaction verify that hydrogen chemisorbs dissociatively to form iron cluster–hydride complexes, FenHm. At low source temperatures, the cluster–hydride complexes take up additional hydrogen molecules which are shown to be physisorbed onto the underlying FenHm complexes to form FenHm(H2)p species. The infrared spectra of FenHm and FenDm (n = 9–20) were obtained by the photodissociation action spectroscopic method in which depletion of the FenHm(H2)p and FenDm(D2)p species was the signature of absorption. The spectra, recorded in the 885–1090 cm−1 region, consist of several overlapping bands, each approximately 20 cm−1 in width. The dissimilarity of each FenHm(H2)p spectrum with the corresponding FenDm(D2)p spectrum indicates that the carrier involves hydrogen and is not merely due to absorption by the underlying iron cluster. Density functional calculations were performed on model complexes, Fe13H14 and Fe13D14, the iron portion of which was assumed to have Th symmetry. The infrared-active vibrational frequencies involving hydrogen bending and deuterium stretching are predicted to lie within the experimental frequency range of the experiment, well removed from the skeletal modes of the underlying iron cluster. The complexity of the observed spectra as compared to simulations based on the assumed (high-symmetry) model imply that the experimentally produced complexes possess low symmetry

Gender and Participation in an Engineering Problem-Based Learning Environment

The use of problem-based learning (PBL) is gaining attention in the engineering classroom as a way to help students synthesize foundational knowledge and to better prepare students for practice. In this work, we study the discourse interactions between 27 student teams and two instructors in an engineering PBL environment to analyze how participation is distributed among team members, paying particular attention to the differences between male and female students. There were no statistically significant differences between the amount that male and female students spoke; however, stereotypical gender roles and traditional gendered behavior did manifest in the discussion. Also, regardless of the gender composition of the team, the amount of time that each member talked was usually unbalanced. Our findings lead to recommendations to instructors interacting with student teams and contribute to knowledge about team and gender interactions in PBL environments

Shape-changing nanomagnets: A new approach to in vivo biosensing

The idea that optical color can be determined by size and shape is well known at the nanoscale. Colors of quantum dots and plasmonic nanostructures, for example, can be tuned through particle size and shape. Among others, this has directly enabled many different multi-colored nanoparticle labels that underpin a host of optically-based in vitro bioimaging applications, including multiplexed high-throughput bioassays and colorimetric sensing and visualization of biomolecular processes and function. Imaging and sensing in more realistic in vivo environments is more challenging, however. Optical probes can be sized or shaped to yield resonances closer to the more optically favorable near-infrared window, but optical penetration, signal intensity, and spatial resolution, still deteriorate rapidly with increasing depth beneath the surface. But what about in the radio-frequency (RF) portion of the spectrum? Are there any analogous nanoparticle structures that can shift the frequency, or equivalently color, of RF signals for which penetration and/or distortion through biological tissue would no longer be a limitation and where imaging and sensing would be naturally immune to any photostability, phototoxicity, and autofluoresence background issues? Please click Additional Files below to see the full abstract