Borrowing historical information for non-inferiority trials on Covid-19 vaccines.

Non-inferiority vaccine trials compare new candidates to active controls that provide clinically significant protection against a disease. Bayesian statistics allows to exploit pre-experimental information available from previous studies to increase precision and reduce costs. Here, historical knowledge is incorporated into the analysis through a power prior that dynamically regulates the degree of information-borrowing. We examine non-inferiority tests based on credible intervals for the unknown effects-difference between two vaccines on the log odds ratio scale, with an application to new Covid-19 vaccines. We explore the frequentist properties of the method and we address the sample size determination problem.

Durability and determinants of anti-SARS-CoV-2 spike antibodies following the second and third doses of mRNA COVID-19 vaccine.

OBJECTIVES: To examine the differences in durability and its determinants of humoral immunity following 2- and 3-dose COVID-19 vaccination. METHODS: Throughout the pandemic, we evaluated the anti-spike IgG antibody titers of 2- and 3-dose mRNA vaccine recipients over time among the staff of a medical and research center in Tokyo. Linear mixed models were used to estimate trajectories of antibody titers from 14 to 180 days after the last immune-conferred event (vaccination or infection) and compare antibody waning rates across prior infection and vaccination status, and across background factors in infection-naïve participants. RESULTS: A total of 6901 measurements from 2964 participants (median age, 35 years; 30% male) were analyzed. Antibody waning rate (percentage per 30 days [95% CI]) was slower after 3 doses (25% [23-26]) than 2 doses (36% [35-37]). Participants with hybrid immunity (vaccination and infection) had further slower waning rates: 2-dose plus infection (16% [9-22]); 3-dose plus infection (21% [17-25]). Older age, male sex, obesity, coexisting diseases, immunosuppressant use, smoking, and alcohol drinking were associated with lower antibody titers, whereas these associations disappeared after 3 doses, except for sex (lower in female participants) and immunosuppressant use. Antibody waned slightly faster in older participants, females, and alcohol drinkers after 2 doses, whereas it did not differ after 3 doses across except sex. DISCUSSION: The 3-dose mRNA vaccine conferred higher durable antibody titers, and previous infection modestly enhanced its durability. The antibody levels at a given time point and waning speed after 2 doses differed across background factors; however, these differences mostly diminished after 3 doses.

UMVUEs and Bayes estimators for various performance measures on a Poisson queue with discouraged arrivals

To prevent overcrowding during the COVID-19 pandemic, numerous businesses, and public service systems have to limit the number of people entering the premises to reduce infection risks. Such a realistic situation prompts us to revisit an adaptive queueing model from a statistical perspective, which allows us to extensively analyze and explore the stochastic service system arising in the pandemic period. In order to avoid long waiting lines, we assume that the arrival rate of customers into the system depends on the system size instead of a constant rate. This article attempts to study the uniformly minimum variance unbiased estimators and closed-form Bayes estimators of various queueing characteristics, such as the probability that the server is busy, the proportion of lost customers, mean system length, and average queue length. The estimates and their behaviors are compared by Monte-Carlo simulation with different sample sizes. The simulation results show that we may choose different estimation techniques for different performance indicators to obtain a more precise estimate. [ FROM AUTHOR] Copyright of Communications in Statistics: Theory & Methods is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Spectral adjustment for spatial confounding

Adjusting for an unmeasured confounder is generally an intractable problem, but in the spatial setting it may be possible under certain conditions. We derive necessary conditions on the coherence between the exposure and the unmeasured confounder that ensure the effect of exposure is estimable. We specify our model and assumptions in the spectral domain to allow for different degrees of confounding at different spatial resolutions. One assumption that ensures identifiability is that confounding present at global scales dissipates at local scales. We show that this assumption in the spectral domain is equivalent to adjusting for global-scale confounding in the spatial domain by adding a spatially smoothed version of the exposure to the mean of the response variable. Within this general framework, we propose a sequence of confounder adjustment methods that range from parametric adjustments based on the Matern coherence function to more robust semiparametric methods that use smoothing splines. These ideas are applied to areal and geostatistical data for both simulated and real datasets.

Closing the Gap Between Decision Analysis and Policy Analysts Before the Next Pandemic

Decision analysis (DA) is an explicitly prescriptive discipline that separates beliefs about uncertainties from value preferences in modeling to support decision making. Researchers have been advancing DA tools for the last 60 years to support decision makers handling complex decisions requiring subjective judgments. Recently, some DA researchers and practitioners wondered whether the difficult decisions made during the COVID-19 pandemic regarding testing, masking, closing and reopening businesses, allocating ventilators, and prioritizing vaccines would have been improved with more DA involvement. With its focus on quantifying uncertainties, value trade-offs, and risk attitudes, DA should have been a valuable tool for decision makers during the pandemic. To influence decisions, DA applications require interactions with policymakers and experts to construct formal representations of the decision frame, elicit uncertainties, and assess risk tolerances and trade-offs among competing objectives. Unfortunately, such involvement of decision analysts in the process of decision making and policy setting did not occur during much of the COVID-19 pandemic. This lack of participation may have been partly because many decision makers were unaware of when DA could be valuable in helping with the challenges of the COVID-19 pandemic. In addition, decision analysts were perhaps not sufficiently adept at inserting themselves into the policy process at critical junctures when their expertise could have been helpful.

Symptoms of anxiety and depression during the COVID-19 pandemic in six European countries and Australia - Differences by prior mental disorders and migration status.

BACKGROUND: Little is known about changes of mental health during the COVID-19 pandemic in potentially disadvantaged groups. We investigated changes in anxiety and depression symptoms during the first year of the pandemic in six European countries and Australia by prior mental disorders and migration status. METHODS: Overall, 4674 adults answered a web-based survey in May-June 2020 and were followed by three repeated surveys up to February 2021. Information on psychosocial, financial and demographic, living conditions, prior mental disorders, depression and anxiety symptoms during the pandemic and migration status was collected. Weighted general estimation equations modelling was used to investigate the association between prior mental disorders, migration status, and symptoms over time. RESULTS: Most participants were <40 years old (48%), women (78%) and highly educated (62%). The baseline prevalence of depressive and anxiety symptoms ranged between 19%-45% and 13%-35%, respectively. In most countries, prevalence rates remained unchanged throughout the pandemic and were higher among people with prior mental disorders than without even after adjustment for several factors. We observed interactions between previous mental disorders and symptoms of anxiety or depression over time in two countries. No difference by migration status was noted. LIMITATIONS: Convenience sampling limits generalizability. Self-assessed symptoms of depression and anxiety might involve some misclassification. CONCLUSIONS: Depression and anxiety symptoms were worse among individuals with prior mental disorders than without, but there was no clear trend of worsening mental health in the observed groups during the observed period.

Primary students' online homework completion and learning achievement

Online homework has become an important teaching and learning activity due to the impact of COVID-19 pandemic-related restrictions. This study explored the relationship between primary students' online homework completion and learning achievement. It also investigated the moderating effects of key factors including the role of the students and the involvement of their parents on this relationship. Based on a total of 3,210 Chinese online homework assigned in the Spring of 2020 to fourth grade primary school students in Wuhan, China, hierarchical linear modeling was employed to examine the relationship between primary students' online homework completion and their learning achievement. Simultaneously, the effects of potential moderators including students' information literacy, students' prior academic achievement, parental digital self-efficacy, and parent - teacher partnership were investigated. The results showed a significant positive effect of students' online homework completion on learning achievement. Moreover, students' information literacy, students' prior achievement, and parent - teacher partnership positively moderated this relationship. Based on the findings, practical implications for school administrators, teachers, and parents are discussed herein to promote online homework completion and enhance students' learning achievement. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

Deep Learning based Lung Segmentation Prior for Robust COVID-19 Classification

Independent of a person's race, COVID-19 is one of the most contagious diseases in the world. The World Health Organization classified the COVID-19 outbreak as a pandemic after noting its global distribution. By using (i) sample-supported analysis and (ii) image-assisted diagnosis, COVID-19 is examined and verified. Our goal is to use CT scan images to identify the COVID-19 infiltrates. The followings steps are used to carry out the suggested work: (i) Automated segmentation with CNN;(ii) Feature mining;(iii) Principal feature selection with Bat-Algorithm;(iv) Classifier implementation using mobile framework and (v) Performance evaluation. We used a variety of automatic segmentation algorithms in our experiment, and the VGG-16 produced better results. This study is evaluated using benchmark datasets gathered, and SVM based RBF kernal classifier system resulted in superior COVID-19 abnormality identification. © 2023 IEEE.

Educational Donors' Expectations and Their Outcomes in the COVID-19 Era: The Moderating Role of Motivation during Sequential Evaluation Phases

Donors' prior expectations of reinforcing satisfaction and favorable attitudes are predicted using Oliver's satisfaction cycle model. This study aims to investigate how prior expectations drive sustainable donation behavior by demonstrating the moderating role of educational donors' motivation to predict further participation behavior. Using three time-lag intervals, our findings show that the relationship between prior expectations (T1) and attitudes toward educational donation (T3) is positive on a longitudinal basis. While this relationship is negatively moderated by the role of donor motivation, the relationship between the expectation of satisfaction and attitudes toward educational donations is not significantly moderated by motivation. In particular, favorable attitudes toward educational donation increase rapidly when prior expectations are high, and motivation is low. This study contributes to the literature by providing evidence for the theoretical mechanisms of the satisfaction cycle model and practical insights for managers during educational donations events. © 2023 by the authors.

Duration of COVID-19 PCR positivity for Omicron vs earlier variants.

There have been reports that the Omicron variant of SARS-CoV-2 is milder and may resolve more quickly than earlier variants of SARS-CoV-2, like the Delta variant. Due to a dearth of studies on duration of PCR positivity for the Omicron variant, we studied this question in a cohort of routinely tested employees that work in a large laboratory. We found that there was no difference in duration of PCR positivity among those infected with the Omicron variant of SARS-CoV-2 versus earlier variants of SARS-CoV-2. That suggests in a clinical study that the increased infectiousness of Omicron might likely be due to factors related to viral and host cell interactions, rather than viral load or duration of infectivity, which has been suggested in immune escape studies.

COMPARISON OF MALAYSIAN URBAN GREEN SPACES USE PRIOR AND DURING THE COVID-19 PANDEMIC AND PREFERENCES FOR POST-PANDEMIC DESIGN IMPROVEMENTS

A survey on the comparison between Malaysians' usage of green spaces prior and during COVID-19 pandemic was conducted using an online self-administered questionnaire. Frequency and descriptive analysis were applied and a total of 415 responses from the whole Malaysia was recorded. Results showed that there was a huge increase in the number of respondents who did not visit the urban green spaces during COVID-19 pandemic. In addition, there was an increase in the use of home garden and neighbourhood park during the pandemic as compared to before the COVID-19 pandemic. The majority of the respondents involved in the survey mentioned that they diverted their visitation to the nearest green spaces available during the pandemic. The findings managed to highlight the changes in usage pattern of green spaces among Malaysians and provide proposals to relevant authorities on the future design of parks and green spaces in post-COVID-19 settings. © 2022 by MIP.

Examining the Impact of IT Experience, Training, Self-Efficacy and Anxiety on Remote Work Quality in Indonesia

In 2020, Covid-19 pandemic has forced millions of individuals worldwide to work remotely with little or no prior experience, for corporations and organizations that are mostly equipped for this change. The third worry concerning remote work quality is whether employees can adjust and what factors influence this. To address such scenarios, a model of remote work self-efficacy was previously established. The development, on the other hand, was intended to evaluate virtual enterprises with dependable ICT and adequate human training. Unprepared, the research attempts to delve deeper into the constituents of its forefathers. The study included 46 participants from the provinces of Jakarta, Central Java, and Yogyakarta in May 2021, when rapid viral spread forced businesses to lock their doors. Unlike other studies, this one show how two-way conversations that generate social persuasion, physiological and emotional states, and self-efficacy improve distant job quality. © 2022 IEEE.

Keep DRAGging ON: Is solving more problems in DragonBox 12+ associated with higher mathematical performance during the COVID-19 pandemic?

Prior research has shown that game-based learning tools, such as DragonBox 12+, support algebraic understanding and that students' in-game progress positively predicts their later performance. Using data from 253 seventh-graders (12–13 years old) who played DragonBox as a part of technology intervention, we examined (a) the relations between students' progress within DragonBox and their algebraic knowledge and general mathematics achievement, (b) the moderating effects of students' prior performance on these relations and (c) the potential factors associated with students' in-game progress. Among students with higher prior algebraic knowledge, higher in-game progress was related to higher algebraic knowledge after the intervention. Higher in-game progress was also associated with higher end-of-year mathematics achievement, and this association was stronger among students with lower prior mathematics achievement. Students' demographic characteristics, prior knowledge and prior achievement did not significantly predict in-game progress beyond the number of intervention sessions students completed. These findings advance research on how, for whom and in what contexts game-based interventions, such as DragonBox, support mathematical learning and have implications for practice using game-based technologies to supplement instruction. Practitioner notes What is already known about this topic DragonBox 12+ may support students' understanding of algebra but the findings are mixed. Students who solve more problems within math games tend to show higher performance after gameplay. Students' engagement with mathematics is often related to their prior math performance. What this paper adds For students with higher prior algebraic knowledge, solving more problems in DragonBox 12+ is related to higher algebraic performance after gameplay. Students who make more in-game progress also have higher mathematics achievement, especially for students with lower prior achievement. Students who spend more time playing DragonBox 12+ make more in-game progress;their demographic, prior knowledge and prior achievement are not related to in-game progress. Implications for practice and/or policy DragonBox 12+ can be beneficial as a supplement to algebra instruction for students with some understanding of algebra. DragonBox 12+ can engage students with mathematics across achievement levels. Dedicating time and encouraging students to play DragonBox 12+ may help them make more in-game progress, and in turn, support math learning. © 2023 The Authors. British Journal of Educational Technology published by John Wiley & Sons Ltd on behalf of British Educational Research Association.

Prior effective sample size in phase II clinical trials with mixed binary and continuous responses

The problem of finding Effective Sample Size (ESS) in Phase II clinical trials where toxicity and efficacy are the two components of the treatment response vector is considered. In particular, one of the components is assumed to be binary and the other is assumed to be continuous. The case of binary safety and continuous efficacy is studied for different prior distributions under different set up. Theoretical expressions are obtained in various situations. The methods are evaluated and compared by simulation studies. The proposed method is then illustrated by using some real life data on a phase II vaccine trial for Covid‐19.

How do firms learn? Evidence from corporate cash holdings during the COVID‐19 pandemic

We examine the impact of COVID‐19 on US corporate cash holdings. Our findings suggest that greater pandemic exposure is associated with higher corporate cash holdings and that firms learn from prior experiences as they manage their cash policies. More specifically, the level of cash holdings in firms that experienced severe financial constraints during the 2008 credit crisis and firms with prior severe acute respiratory syndrome (SARS) and H1N1 exposure is significantly lower than that of firms with no prior epidemic or financial constraints experience. Overall, our findings support the learning behaviour of cash and contribute to corporate cash holdings literature by providing insights on the extent to which firms learn from prior experiences to manage their liquidity.

Implementation and Experiences of a Flipped Lecture Hall - A Fully Online Introductory Programming Course

The course Introduction to Programming is one of the first and fundamental courses within any computer science-related study program. Traditionally, such introductory courses are characterized by a large group of students, whereas this group has a heterogeneous prior knowledge of the topic. These courses are usually taught in a traditional setting due to a high number of participants. However, the Covid-19 pandemic situation required to shift from traditional teaching to alternative approaches. In the winter semester 2020, a total of 636 students actively participated in the course at Graz University of Technology. Therefore, the course was revised to a fully online flipped classroom course using asynchronous elements such as pre-recorded videos and synchronous elements such as live streams on Twitch. In this paper, we show how we implemented a fully online course using the flipped classroom approach. We present approaches that engage students in active participation and encourage self-paced learning. We found that a high community-related interaction with students has a major impact on students satisfaction. This can be reached using lively communication and different communication channels. These results may be useful for researchers and lecturers that want to have insights into experiences in flipped classroom settings. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Corrigendum: Factors Influencing Employees' Subjective Wellbeing and Job Performance During the COVID-19 Global Pandemic: The Perspective of Social Cognitive Career Theory.

[This corrects the article DOI: 10.3389/fpsyg.2021.577028.].

Protection From COVID-19 mRNA Vaccination and Prior SARS-CoV-2 Infection Against COVID-19-Associated Encounters in Adults During Delta and Omicron Predominance.

BACKGROUND: Data assessing protection conferred from COVID-19 mRNA vaccination and/or prior SARS-CoV-2 infection during Delta and Omicron predominance periods in the United States are limited. METHODS: This cohort study included persons ≥18 years who had ≥1 health care encounter across 4 health systems and had been tested for SARS-CoV-2 before 26 August 2021. COVID-19 mRNA vaccination and prior SARS-CoV-2 infection defined the exposure. Cox regression estimated hazard ratios (HRs) for the Delta and Omicron periods; protection was calculated as (1-HR)×100%. RESULTS: Compared to unvaccinated and previously uninfected persons, during Delta predominance, protection against COVID-19-associated hospitalizations was high for those 2- or 3-dose vaccinated and previously infected, 3-dose vaccinated alone, and prior infection alone (range, 91%-97%, with overlapping 95% confidence intervals [CIs]); during Omicron predominance, estimates were lower (range, 77%-90%). Protection against COVID-19-associated emergency department/urgent care (ED/UC) encounters during Delta predominance was high for those exposure groups (range, 86%-93%); during Omicron predominance, protection remained high for those 3-dose vaccinated with or without a prior infection (76%; 95% CI = 67%-83% and 71%; 95% CI = 67%-73%, respectively). CONCLUSIONS: COVID-19 mRNA vaccination and/or prior SARS-CoV-2 infection provided protection against COVID-19-associated hospitalizations and ED/UC encounters regardless of variant. Staying up-to-date with COVID-19 vaccination still provides protection against severe COVID-19 disease, regardless of prior infection.

Neutralizing antibodies and T-cell responses to inactivated SARS-CoV-2 vaccine in COVID-19 convalescents one and a half years after infection.

Vaccines have been considered the most promising solution for ending the coronavirus disease 2019 (COVID-19) pandemic. Information regarding neutralizing antibodies (NAbs) and T-cell immune response in inactivated SARS-CoV-2 vaccine-immunized COVID-19 convalescent patients were either only available for a short time after illness recovered or not available at all (T-cell immunity). We evaluated SARS-CoV-2 NAbs and cellular immune responses to the SARS-CoV-2 inactivated vaccine in convalescent patients who recovered from infection for about one and a half years. We found that compared to before vaccination, SARS-CoV-2 NAbs and specific T-cell responses were significantly boosted by the inactivated vaccine in convalescent patients, which confirmed the pre-existing adaptive immunity in SARS-CoV-2 infected people. We observed that NAbs and IFN-γ-secreting T-cell response elicited by a single vaccine dose in subjects with prior COVID-19 infection were higher than after two doses of vaccine in SARS-CoV-2 naïve subjects. Both humoral and cellular immune responses elicited by one and two doses of inactivated vaccine were comparable in COVID-19-recovered persons. In conclusion, inactivated COVID-19 vaccine induced robust NAbs and T-cell responses to SARS-CoV-2 in COVID-19 convalescent patients and immune responses after one dose were equal to that after receiving two doses, which highlighted that robust humoral and cellular immune response can be reactivated by the inactivated vaccine in SARS-CoV-2 convalescent patients.

A digital family affair: Do family firms' characteristics enhance consumers' willingness to pay?

Communicating the familiness of the firm allows family businesses to leverage a strategic resource: the idiosyncratic characteristics of the family firms. Drawing on the ontological perspective of the nature of family firm, this study investigates the effect of family firms' characteristics on consumers' willingness to pay (WTP) for family firms' products in an online environment. The study presents a novel context of analysis investigating the mediating effect of frequency of purchase and peer-to-peer online reviews in the digital channel. Results offer support for a direct effect of the family firms' characteristics on consumers' WTP and validate the total effect of mediation of frequency of purchase and peer-to-peer online reviews. The findings provide intriguing implications for practitioners. Defining the antecedents of consumers' WTP for family firms in the online channel shall be helpful for managers to create more efficient communication and marketing campaigns, with the effect of deploying more customer-centric revenue management techniques.