Assessing parameter sensitivity in a university campus COVID-19 model with vaccinations.

From the beginning of the COVID-19 pandemic, universities have experienced unique challenges due to their dual nature as a place of education and residence. Current research has explored non-pharmaceutical approaches to combating COVID-19, including representing in models different categories such as age groups. One key area not currently well represented in models is the effect of pharmaceutical preventative measures, specifically vaccinations, on COVID-19 spread on college campuses. There remain key questions on the sensitivity of COVID-19 infection rates on college campuses to potentially time-varying vaccine immunity. Here we introduce a compartment model that decomposes a campus population into constituent subpopulations and implements vaccinations with time-varying efficacy. We use this model to represent a campus population with both vaccinated and unvaccinated individuals, and we analyze this model using two metrics of interest: maximum isolation population and symptomatic infection. We demonstrate a decrease in symptomatic infections occurs for vaccinated individuals when the frequency of testing for unvaccinated individuals is increased. We find that the number of symptomatic infections is insensitive to the frequency of testing of the unvaccinated subpopulation once about 80% or more of the population is vaccinated. Through a Sobol' global sensitivity analysis, we characterize the sensitivity of modeled infection rates to these uncertain parameters. We find that in order to manage symptomatic infections and the maximum isolation population campuses must minimize contact between infected and uninfected individuals, promote high vaccine protection at the beginning of the semester, and minimize the number of individuals developing symptoms.

Psychological Impact of Cancellation of Elective Surgeries for Ophthalmic Patients during COVID-19 Pandemic.

The COVID-19 pandemic has disrupted routine hospital services globally. The cancellation of elective surgeries placed a psychological burden on patients. A questionnaire study was conducted to identify the psychological impact of canceling cataract operations on patients at Kowloon East Cataract Center, Tseung Kwan O Hospital, Hong Kong, from April to June 2020. In total, 99 participants aged 59 years old and above, who had their cataract surgeries postponed or as scheduled, were studied using the standardized patient health questionnaire (PHQ-9) and generalized anxiety disorder questionnaire (GAD-7). None of the patients who had their cataract surgeries rescheduled reached the cutoff score for major depression in PHQ-9, whereas, according to GAD-7, five patients had mild symptoms of anxiety, and one had severe symptoms. There was no significant psychosocial impact of the cancellation of cataract surgeries on patients.

Optimization and Design of a Flexible Droop-Nose Leading-Edge Morphing Wing Based on a Novel Black Widow Optimization Algorithm—Part I

An aerodynamic optimization for a Droop-Nose Leading-Edge (DNLE) morphing of a well-known UAV, the UAS-S45, is proposed, using a novel Black Widow Optimization (BWO) algorithm. This approach integrates the optimization algorithm with a modified Class-Shape Transformation (CST) parameterization method to enhance aerodynamic performance by minimizing drag and maximizing aerodynamic endurance at the cruise flight condition. The CST parameterization technique is used to parameterize the reference airfoil by introducing local shape changes and provide skin flexibility to obtain various optimized morphing airfoil configurations. The optimization framework uses an in-house MATLAB algorithm, while the aerodynamic calculations use the XFoil solver with flow transition estimation criteria. These results are validated with a CFD solver utilizing the Transition (γ−Reθ) Shear Stress Transport (SST) turbulence model. Numerical studies verified the effectiveness of the optimization strategy, and the optimized airfoils have shown a significant improvement in overall aerodynamic performance by up to 12.18% drag reduction compared to the reference airfoil, and an increase in aerodynamic endurance of up to 10% for the UAS-S45 optimized airfoil configurations over its reference airfoil. These results indicate the importance of leading-edge morphing in enhancing the aerodynamic efficiency of the UAS-S45 airfoil.

Evaluating the sensitivity of SARS-CoV-2 infection rates on college campuses to wastewater surveillance.

As college campuses reopened in fall 2020, we saw a large-scale experiment unfold on the efficacy of various strategies to contain the SARS-CoV-2 virus. Traditional individual surveillance testing via nasal swabs and/or saliva is among the measures that colleges are pursuing to reduce the spread of the virus on campus. Additionally, some colleges are testing wastewater on their campuses for signs of infection, which can provide an early warning signal for campuses to locate COVID-positive individuals. However, a representation of wastewater surveillance has not yet been incorporated into epidemiological models for college campuses, nor has the efficacy of wastewater screening been evaluated relative to traditional individual surveillance testing, within the structure of these models. Here, we implement a new model component for wastewater surveillance within an established epidemiological model for college campuses. We use a hypothetical residential university to evaluate the efficacy of wastewater surveillance for maintaining low infection rates. We find that wastewater sampling with a 1-day lag to initiate individual screening tests, plus completing the subsequent tests within a 4-day period can keep overall infections within 5% of the infection rates seen with traditional individual surveillance testing. Our results also indicate that wastewater surveillance can effectively reduce the number of false positive cases by identifying subpopulations for surveillance testing where infectious individuals are more likely to be found. Through a Monte Carlo risk analysis, we find that surveillance testing that relies solely on wastewater sampling can be fragile against scenarios with high viral reproductive numbers and high rates of infection of campus community members by outside sources. These results point to the practical importance of additional surveillance measures to limit the spread of the virus on campus and the necessity of a proactive response to the initial signs of outbreak.

Identifying Factors Important to Patients for Resuming Elective Imaging During the COVID-19 Pandemic.

PURPOSE: To identify factors important to patients for their return to elective imaging during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: In all, 249 patients had elective MRIs postponed from March 23, 2020, to April 24, 2020, because of the COVID-19 pandemic. Of these patients, 99 completed a 22-question survey about living arrangement and health care follow-up, effect of imaging postponement, safety of imaging, and factors important for elective imaging. Mann-Whitney U, Fisher's exact, χ2 tests, and logistic regression analyses were performed. Statistical significance was set to P ≤ .05 with Bonferroni correction applied. RESULTS: Overall, 68% of patients felt imaging postponement had no impact or a small impact on health, 68% felt it was fairly or extremely safe to obtain imaging, and 53% thought there was no difference in safety between hospital-based and outpatient locations. Patients who already had imaging performed or rescheduled were more likely to feel it was safe to get an MRI (odds ratio [OR] 3.267, P = .028) and that the hospital setting was safe (OR 3.976, P = .004). Staff friendliness was the most important factor related to an imaging center visit (95% fairly or extremely important). Use of masks by staff was the top infection prevention measure (94% fairly or extremely important). Likelihood of rescheduling imaging decreased if a short waiting time was important (OR = 0.107, P = .030). CONCLUSION: As patients begin to feel that it is safe to obtain imaging examinations during the COVID-19 pandemic, many factors important to their imaging experience can be considered by radiology practices when developing new strategies to conduct elective imaging.