This study explores how individuals make use of scientific content knowledge for socioscientific argumentation. More specifically, this mixed‐methods study investigates how learners apply genetics content knowledge as they justify claims relative to genetic engineering. Interviews are conducted with 45 participants, representing three distinct groups: high school students with variable genetics knowledge, college nonscience majors with little genetics knowledge, and college science majors with advanced genetics knowledge. During the interviews, participants advance positions concerning three scenarios dealing with gene therapy and cloning. Arguments are assessed in terms of the number of justifications offered as well as justification quality, based on a five‐point rubric. Multivariate analysis of variance results indicate that college science majors outperformed the other groups in terms of justification quality and frequency. Argumentation does not differ among nonscience majors or high school students. Follow‐up qualitative analyses of interview responses suggest that all three groups tend to focus on similar, sociomoral themes as they negotiate socially complex, genetic engineering issues, but that the science majors frequently reference specific science content knowledge in the justification of their claims. Results support the Threshold Model of Content Knowledge Transfer, which proposes two knowledge thresholds around which argumentation quality can reasonably be expected to increase. Research and educational implications of these findings are discussed. © 2006 Wiley Periodicals, Inc. Sci Ed 90:986–1004, 2006

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Traditionally underserved students (TUSs), including Black, Latinx, American Native, and low-socioeconomic (SES) students, have higher rates of departure from STEM undergraduate programs than their more privileged peers. These higher departure rates are associated with TUSs' lower performance in STEM gatekeeper courses compared to non-STEM courses through their sophomore year. Flipped models of instruction when used in gatekeeper chemistry courses are broadly shown to improve student course performance (higher course grades; reduced W/D/F rates). However, there is no clear evidence that flipped models specifically improve course performance for TUSs. This study's objective was to determine the impact of a flipped model on students' course performance in General Chemistry I on the basis of their race/ethnicity and SES. Using a nonparallel quasi-experimental design, student performance by race/ethnicity and SES in the flipped model course was compared to that of students in the traditional course. Results show TUSs were significantly more likely to have higher course grades in the flipped model course as compared to the traditional course. Further, the performance gap was closed between Black and Latinx students and their White/Asian peers in the flipped model. However, a performance gap between low-SES and middle-to high-SES students emerged in the flipped model. The W/D/F rate was decreased in the flipped model for all student groups. Therefore, although flipped models are not a panacea, they can be one critical support strategy used in freshman and sophomore chemistry gatekeeper courses to mitigate TUSs' departure from STEM undergraduate programs.

Lamin B receptor (LBR) is a bifunctional nuclear membrane protein with N-terminal lamin B and chromatin binding domains plus a C-terminal sterol Δ14 reductase domain. LBR expression increases during neutrophil differentiation and deficient expression disrupts neutrophil nuclear lobulation characteristic of Pelger-Huët anomaly. Thus LBR plays a critical role in regulating myeloid differentiation, but how the two functional domains of LBR support this role is currently unclear. We previously identified abnormal proliferation and deficient functional maturation of promyelocytes (EPRO cells) derived from EML-ic/ic cells, a myeloid model of ichthyosis (ic) bone marrow that lacks Lbr expression. Here we provide new evidence that cholesterol biosynthesis is important to myeloid cell growth and is supported by the sterol reductase domain of Lbr. Cholesterol biosynthesis inhibitors caused growth inhibition of EML cells that increased in EPRO cells, whereas cells lacking Lbr exhibited complete growth arrest at both stages. Lipid production increased during wild-type neutrophil maturation, but ic/ic cells exhibited deficient levels of lipid and cholesterol production. Ectopic expression of a full length Lbr in EML-ic/ic cells rescued both nuclear lobulation and growth arrest in cholesterol starvation conditions. Lipid production also was rescued, and a deficient respiratory burst was corrected. Expression of just the C-terminal sterol reductase domain of Lbr in ic/ic cells also improved each of these phenotypes. Our data support the conclusion that the sterol Δ14 reductase domain of LBR plays a critical role in cholesterol biosynthesis, and that this process is essential to both myeloid cell growth and functional maturation.

LTE and LTE-Advanced mobile technologies have integrated discontinuous reception (DRX) power saving method to optimize the power consumption at the user equipment (UE). The DRX method was proposed by the 3rd Generation partnership Project (3GPP), and since then, the traffic behavior has been analyzed in several studies with a standard 3-state DRX model to describe the trade-off between power saving and delay. In this paper, we presented a novel 4-state and 5-state 3GPP LTE DRX mechanisms. The proposed mechanisms were developed by augmenting (an) active state(s) to deep and/or light sleep cycle of standard 3-state DRX for handling a small burst of packets, thereby bypassing the process of returning to the timer-dependent active mode. We have generated analytical models using a semi-Markov process for bursty packet data traffic and evaluated these augmented DRX mechanisms against a standard 3-state DRX method. Overall, the analytical results from varying timing parameters showed that our augmented DRX (both 4-state and 5-state) improved power saving factor (ranging between 1% and 8%) and reduced delay (ranging between 20% and 60%) compared to the standard 3-state DRX. Furthermore, the magnitude of improvement for both delay and power-saving was somewhat greater in 5-state than 4-state.