Living-learning communities improve first-year engineering student academic performance and retention at a small private university

Living-Learning Communities (LLCs), in which students share a residence, one or more classes, and extracurricular activities, have been shown to improve first-year student engagement, academic performance, and retention in non-engineering fields. Research on Engineering LLCs has focused primarily on student engagement. Two studies to examine performance and retention found that LLCs had little effect on first-semester grades but increased first-year retention in engineering by 2 to 12%. Unfortunately, one of these studies did not control for differences in incoming student characteristics, and another used a comparison group that differed little from the LLC group, possibly causing them to understate the LLC’s true effects. To improve our understanding, this paper examines performance and retention in the inaugural Engineering LLCs at a small, private non-profit, regional university in the northeastern United States. Results indicate that 82% of the Engineering LLC participants were retained within the engineering program, compared to 66% of first-year engineering students who chose not to participate. More strikingly, the average first-semester GPA of the LLC participants was 0.31 points (nearly a third of a letter grade) higher than that of the non-participants. To address the possibility that these improvements were caused by differences in incoming student characteristics, linear and logistic regression analyses were performed to control for gender, race/ethnicity, SAT scores, and other factors. These analyses suggest that LLC participation increased GPA by 0.35 points compared to first-year engineering students from prior years, while non-participation lowered GPA by 0.07 points. LLC participation increased the odds of retention in the major by 2.3 times compared to first-year students from prior years, while nonparticipation lowered the odds of retention by 1.35 times

Cell cycle regulation of a Xenopus Wee1-like kinase

Using a polymerase chain reaction-based strategy, we have isolated a gene encoding a Wee1-like kinase from Xenopus eggs. The recombinant Xenopus Wee1 protein efficiently phosphorylates Cdc2 exclusively on Tyr- 15 in a cyclin-dependent manner. The addition of exogenous Wee1 protein to Xenopus cell cycle extracts results in a dose-dependent delay of mitotic initiation that is accompanied by enhanced tyrosine phosphorylation of Cdc2. The activity of the Wee1 protein is highly regulated during the cell cycle: the interphase, underphosphorylated form of Wee1 (68 kDa) phosphorylates Cdc2 very efficiently, whereas the mitotic, hyperphosphorylated version (75 kDa) is weakly active as a Cdc2-specific tyrosine kinase. The down-modulation of Wee1 at mitosis is directly attributable to phosphorylation, since dephosphorylation with protein phosphatase 2A restores its kinase activity. During interphase, the activity of this Wee1 homolog does not vary in response to the presence of unreplicated DNA. The mitosis-specific phosphorylation of Wee1 is due to at least two distinct kinases: the Cdc2 protein and another activity (kinase X) that may correspond to an MPM-2 epitope kinase. These studies indicate that the down-regulation of Wee1-like kinase activity at mitosis is a multistep process that occurs after other biochemical reactions have signaled the successful completion of S phase

Extending the dynamic range of transcription factor action by translational regulation

A crucial step in the regulation of gene expression is binding of transcription factor (TF) proteins to regulatory sites along the DNA. But transcription factors act at nanomolar concentrations, and noise due to random arrival of these molecules at their binding sites can severely limit the precision of regulation. Recent work on the optimization of information flow through regulatory networks indicates that the lower end of the dynamic range of concentrations is simply inaccessible, overwhelmed by the impact of this noise. Motivated by the behavior of homeodomain proteins, such as the maternal morphogen Bicoid in the fruit fly embryo, we suggest a scheme in which transcription factors also act as indirect translational regulators, binding to the mRNA of other transcription factors. Intuitively, each mRNA molecule acts as an independent sensor of the TF concentration, and averaging over these multiple sensors reduces the noise. We analyze information flow through this new scheme and identify conditions under which it outperforms direct transcriptional regulation. Our results suggest that the dual role of homeodomain proteins is not just a historical accident, but a solution to a crucial physics problem in the regulation of gene expression.Comment: 14 pages, 5 figure

Ultraviolet spectroscopy of meteoric debris: In situ calibration experiments from earth orbit

It is proposed to carry out slitless spectroscopy at ultraviolet wavelengths from orbit of meteoric debris associated with comets. The Eta Aquarid, Orionid/Halley, and the Persied/1962 862 Swift-Tuttle showers would be principal targets. Low light level, ultraviolet video technique will be used during the night side of the orbit in a wide field, earthward viewing mode. Data will be stored in compact video cassette recorders. The experiment may be configured as a GAS package or in the HITCHHIKER mode. The latter would allow flexible pointing capability beyond that offered by shuttle orientation of the GAS package, and doubling of the data record. The 1100 to 3200 A spectral region should show emissions of atomic, ionic, and molecular species of interest on cometary and solar system studies

Do Childhood Vaccines Have Non-Specific Effects on Mortality

A recent article by Kristensen et al. suggested that measles vaccine and bacille Calmette–Guérin (BCG) vaccine might\ud reduce mortality beyond what is expected simply from protection against measles and tuberculosis. Previous reviews of the potential effects of childhood vaccines on mortality have not considered methodological features of reviewed studies. Methodological considerations play an especially important role in observational assessments, in which selection factors for vaccination may be difficult to ascertain. We reviewed 782 English language articles on vaccines and childhood mortality and found only a few whose design met the criteria for methodological rigor. The data reviewed suggest that measles vaccine delivers its promised reduction in mortality, but there is insufficient evidence to suggest a mortality benefit above that caused by its effect on measles disease and its sequelae. Our review of the available data in the literature reinforces how difficult answering these considerations has been and how important study design will be in determining the effect of specific vaccines on all-cause mortality.\u

Clinical outcomes and patterns of care in the treatment of carcinosarcoma of the breast

Purpose: Carcinosarcoma of the breast is a rare yet highly aggressive tumor accounting for \u3c1% of all breast cancers, for which guidance on optimal management and prognosis are sparse. The purpose of this study was to investigate population-based treatment patterns and overall survival (OS) outcomes in patients with this diagnosis. Materials and Methods: We queried the National Cancer Database for patients diagnosed with carcinosarcoma of the breast. All patients included were treated with surgery in the form of mastectomy or lumpectomy, with or without chemotherapy and/or radiation therapy. Patients with metastatic disease were excluded. Kaplan-Meier analysis was used to estimate OS. Univariate and multivariable Cox analyses were used to determine predictive factors of OS. Results: A total of 329 patients from 2004 to 2012 were identified. Median age at diagnosis was 58 years (range, 24-90). Patients had T1 (21%), T2 (44%), T3 (25%), or T4 disease (10%). Most patients were node-negative at diagnosis (77%). Breast conservation surgery was utilized in 33% of patients. Chemotherapy was used in 66% of patients. Less than half (44%) of patients received radiation therapy to a median dose of 50.4 Gy (range 35-56 Gy), with a median 10 Gy boost used in 76%. With a median follow-up of 40.0 months, 3- and 5-year OS for all patients was 74% and 60%, respectively. Kaplan-Meier estimates revealed the 3-yr OS was 80% in patients receiving chemotherapy vs 59% without chemotherapy (P \u3c 0.001). The 3-yr OS was 82% in patients receiving RT vs 66% without RT (P = 0.001). On multivariable analysis, OS was significantly influenced by Charlson-Deyo comorbidity index, insurance status, clinical T stage, surgical margin status, and treatment group, with trimodality therapy (HR: 0.45, 95% CI: 0.27-0.78; P = 0.004) and surgery plus CT (HR: 0.54, 95% CI: 0.33-0.90; P = 0.02) being associated with the greatest OS. Logistic regression revealed only younger patients were more likely to receive trimodality therapy. Conclusions: Carcinosarcoma of the breast is associated with relatively poor rates of OS. The addition of CT and RT to surgery improves OS. Trimodality therapy and surgery plus CT were associated with the greatest OS compared to surgery alone