David Flesner, Professor Emeritus of Mathematics

In this new Next Page column, David Flesner, Professor Emeritus of Mathematics, explains why he is a big fan of author Dan Brown, which book inspired him as a child to pursue mathematics, why he adopted “Fyodor” as a class name in high school, and much more

Using dew points to estimate savings during a planned cooling shutdown

In an effort to save money during the summer of 2003, Northern Illinois University (NIU) administrators instituted a four-day working week and stopped air conditioning buildings for the three-day weekends (Friday through Sunday). Shutting down the air conditioning systems caused a noticeable drop in electricity usage for that part of the campus that features in our study, with estimated total electricity savings of 1,268,492 kilowatt-hours or 17% of the average usage during that eight-week period. NIU’s air conditioning systems, which relied on evaporative cooling to function, were sensitive to dew point levels. Greatest savings during the shutdown period occurred on days with higher dew points. An examination of the regional dew point climatology (1959–2003) indicated that the average summer daily dew point for 2003 was 14.9◦C (58.8◦F), which fell in the lowest 20% of the distribution. Based on the relationship between daily average dew points and electrical usage, a predictive model that could estimate electrical daily savings was created. This model suggests that electrical savings related to any future three-day shutdowns over summer could be much greater in more humid summers. Studies like this demonstrate the potential value of applying climatological information and of integrating this information into practical decision-making

An evaluation of risk factors for major adverse cardiovascular events during tocilizumab therapy

Objective: To evaluate associations between lipid levels, inflammation, and rheumatoid arthritis (RA) disease activity, at baseline and during treatment, with the risk of major adverse cardiovascular events (MACE) in tocilizumab‐treated patients with RA. Methods: In retrospective post hoc analyses, data were pooled for 3,986 adult patients with moderate to severe RA who received ≥1 dose of tocilizumab (4 mg/kg or 8 mg/kg) intravenously every 4 weeks in randomized controlled trials and extension studies. Cox proportional hazards modeling was used to evaluate associations between baseline characteristics and posttreatment changes in laboratory and disease characteristics (week 24) and change in disease activity and laboratory values from baseline to week 24 with the risk of future MACE during extended followup. Results: We identified 50 independently adjudicated cases of MACE during 14,683 patient‐years of followup (0.34 MACE cases/100 patient‐years). At baseline, age, a history of cardiac disorders, the Disease Activity Score in 28 joints (DAS28), and the total cholesterol:high‐density lipoprotein cholesterol ratio were independently associated with MACE in multivariable models (P < 0.05 for all). During treatment, a higher DAS28 and higher swollen and tender joint counts at week 24 were associated with future MACE. In separate models, greater reductions in the DAS28 and joint counts from baseline to week 24 were inversely associated with future MACE; changes in lipid parameters were not statistically significantly associated with the risk of MACE. Conclusion: In this population of patients treated with tocilizumab, an association was observed between the baseline total cholesterol:high‐density lipoprotein cholesterol ratio and an increased risk of MACE. The risk of MACE while receiving treatment, however, was associated with control of disease activity but not lipid changes. Larger studies are needed to confirm these findings

In Solidarity

This edition of Next Page is a departure from our usual question and answer format with a featured campus reader. Instead, we asked speakers who participated in the College’s recent Student Solidarity Rally (March 1, 2017) to recommend readings that might further our understanding of the topics on which they spoke

chroGPS, a global chromatin positioning system for the functional analysis and visualization of the epigenome

Development of tools to jointly visualize the genome and the epigenome remains a challenge. chroGPS is a computational approach that addresses this question. chroGPS uses multidimensional scaling techniques to represent similarity between epigenetic factors, or between genetic elements on the basis of their epigenetic state, in 2D/3D reference maps. We emphasize biological interpretability, statistical robustness, integration of genetic and epigenetic data from heterogeneous sources, and computational feasibility. Although chroGPS is a general methodology to create reference maps and study the epigenetic state of any class of genetic element or genomic region, we focus on two specific kinds of maps: chroGPSfactors, which visualizes functional similarities between epigenetic factors, and chroGPSgenes, which describes the epigenetic state of genes and integrates gene expression and other functional data. We use data from the modENCODE project on the genomic distribution of a large collection of epigenetic factors in Drosophila, a model system extensively used to study genome organization and function. Our results show that the maps allow straightforward visualization of relationships between factors and elements, capturing relevant information about their functional properties that helps to interpret epigenetic information in a functional context and derive testable hypotheses

Common mental disorders and mortality in the West of Scotland Twenty-07 Study: comparing the General Health Questionnaire and the Hospital Anxiety and Depression Scale

Background While various measures of common mental disorders (CMD) have been found to be associated with mortality, a comparison of how different measures predict mortality may improve our understanding of the association. This paper compares how the Hospital Anxiety and Depression Scale (HADS) and the 30-item General Health Questionnaire (GHQ-30) predict all cause and cause-specific mortality. Methods Data on 2547 men and women from two cohorts, aged approximately 39 and 55 years, from the West of Scotland Twenty-07 Study who were followed up for mortality over an average of 18.9 (SD 5.0) years. Scores were calculated for HADS depression (HADS-D), HADS Anxiety (HADS-A) and GHQ-30. Cox Proportional Hazards Models were used to determine how each CMD measure predicted mortality. Results After adjusting for serious physical illness, smoking, social class, alcohol, obesity, pulse rate and living alone, HRs (95% CI) per SD increase in score for all-cause mortality were: 1.15 (1.07 to 1.25) for HADSD; 1.13 (1.04 to 1.23) for GHQ-30 and 1.05 (0.96 to 1.14) for HADS-A. After the same adjustments, cardiovascular disease mortality was also related to HADS-D (HR 1.24 (1.07 to 1.43)), to GHQ-30 (HR 1.24 (1.11 to 1.40)) and to HADS-A (HR 1.15 (1.01 to 1.32)); respiratory mortality to GHQ-30 (HR 1.33 (1.13 to 1.55)) and mortality from other causes, excluding injuries, to HADS-D (HR 1.28 (1.05 to 1.55)). Conclusions There were associations between CMD and both all-cause and cause-specific mortality which were broadly similar for GHQ-30 and HADS-D and were still present after adjustment for important confounders and mediators

Nanostructured conformal hybrid solar cells: a promising architecture towards complete charge collection and light absorption

We introduce hybrid solar cells with an architecture consisting of an electrodeposited ZnO nanorod array (NRA) coated with a conformal thin layer (< 50 nm) of organic polymer-fullerene blend and a quasi-conformal Ag top contact (Thin/NR). We have compared the performance of Thin/NR cells to conventional hybrid cells in which the same NRAs are completely filled with organic blend (Thick/NR). The Thin/NR design absorbs at least as much light as Thick/NR cells, while charge extraction is significantly enhanced due to the proximity of the electrodes, resulting in a higher current density per unit volume of blend and improved power conversion efficiency. The NRAs need not be periodic or aligned and hence can be made very simply

Cardiovascular safety of tocilizumab versus etanercept in rheumatoid arthritis: a randomized controlled trial

Objective: To compare the risk for major adverse cardiovascular events (MACE) in RA patients treated with tocilizumab versus the tumor necrosis factor inhibitor etanercept. Methods: This randomized, open‐label, parallel‐group trial enrolled patients with active seropositive RA (N=3080), inadequate responses to conventional synthetic disease‐modifying antirheumatic drugs, and at least one cardiovascular risk factor. Patients were randomly assigned 1:1 to open‐label tocilizumab 8 mg/kg/month or etanercept 50 mg/week and followed up for an average of 3.2 years. The primary end point was comparison of time‐to‐first MACE. The trial was powered to exclude a 1.8 or higher relative hazard of MACE for tocilizumab versus etanercept. Results: By week 4, serum low‐density lipoprotein cholesterol, high‐density lipoprotein cholesterol, and triglyceride levels were 11.1%, 5.7%, and 13.6% higher, respectively, for patients allocated to tocilizumab compared with etanercept (all P<.001). During follow‐up, 83 MACE occurred in the tocilizumab group compared with 78 in the etanercept group. The estimated hazard of MACE for tocilizumab relative to etanercept was 1.05 (95% confidence interval=0.77, 1.43). Result were similar in sensitivity analyses and the on‐treatment analysis. Adverse events that occurred more frequently in the tocilizumab group included serious infection and gastrointestinal perforation. Conclusion: The trial, which provides insights into the cardiovascular safety of tocilizumab versus etanercept, excluded a relative risk for MACE of 1.43 or higher. This result should be interpreted in the context of the clinical efficacy and the non‐cardiovascular safety of tocilizumab

Symbols for Computer-Aided Design Software Operations: Selection and Effect on User Recall

Computer Aided Design (CAD) software can be difficult to learn. Past research has not investigated how the selection of symbols used to represent CAD operations affects a new user’s ability to learn CAD concepts. In this paper, we explore how symbol choice impacts short-term recall as measured by accuracy and response time. We performed an initial study to identify what 2D symbols users draw to perform common CAD operations. This study identified common symbols for five CAD operations and highlighted differences between symbols drawn by inexperienced and experienced CAD users. Then, we conducted a second study with three groups using different input methods: selecting Autodesk Inventor CAD operation icons, selecting 2D symbols derived from the first study, and physically drawing those same symbols. There is not a statistically significant difference between the three groups’ average question accuracy. For time taken to submit responses, the group selecting Autodesk icons was lowest, followed by the group selecting the symbols, and then the group drawing the symbols. Additionally, the group drawing the symbols had a greater improvement in response time compared to the group selecting Autodesk icons. Other differences between groups were not found to be statistically significant. The results from our second study suggest a negative correlation between our set of user-created symbols and response time, and the potential for further research on other symbols from our first study

Brass Happenings

Presenting a student recital for brass students in USU\u27s Music Department.https://digitalcommons.usu.edu/music_programs/1107/thumbnail.jp