Preventing COVID-19 Outbreaks Using Wastewater Surveillance at Long-Term Care Facilities: A Pilot Modelling Study

Objectives: Site-specific wastewater surveillance could potentially control COVID-19 outbreaks more effectively at long-term care facilities (LTCF). It could identify the presence of pre-symptomatic and asymptomatic COVID-19 infections in the facility and therefore initiate timely outbreak control measures. Besides, compared to repetitive screenings of residents and staff using diagnostic tests, screenings based on positive wastewater test results incur fewer costs and less discomfort. We evaluated the effectiveness of LTCF-site-specific wastewater surveillance in preventing COVID-19 outbreaks, by comparing the scenario where more diagnostic tests were initiated due to positive wastewater test results and the base case of no action. Method(s): We built a susceptible-infected-cases-recovered model to study COVID-19 transmission at LTCF under the base-case and wastewater surveillance scenario. We used data from an outbreak during the Omicron wave in one LTCF in Edmonton, Canada (December 2021 - March 2022), where wastewater data did not initiate actions. We fit base-case model parameters with daily cases and testing data using the nonlinear least-squares method. We hypothesized 10%-50% more diagnostic tests in the wastewater scenario. We compared the outbreak size, i.e., predicted numbers of infections, to measure the effectiveness. We used the Mann-Whitney U test to identify whether the outbreak size in the wastewater scenario was significantly smaller. Result(s): Results reported are subject to minor changes as modelling work is ongoing. The number of infections peaked on day 25 in the base case, with 23.8% of individuals being infected. In the wastewater scenario, all hypothesized values resulted in a significantly smaller outbreak size;only 10% more diagnostic tests could lead to 5.4% fewer infections (p=0.03) at the peak. Conclusion(s): This pilot study demonstrates the potential effectiveness of LTCF-site-specific wastewater surveillance to prevent COVID-19 outbreaks. Future works include engaging policymakers in analyzing specific wastewater-based actions and estimating the costs of controlling COVID-19 to explore the cost-effectiveness of wastewater surveillance.Copyright © 2023

The effects of channel width on particle sedimentation in fluids using a coupled lattice Boltzmann-discrete element model

Understanding particle settlement in channeled fluids has wide applications, such as fine particulate matter, coronavirus particle transport, and the migration of solid particles in water. Various factors have been investigated but few studies have acknowledged the channel's effect on settlement dynamics. This study developed a coupled interpolated bounce-back lattice Boltzmann-discrete element model and examined how a channel's width affects particle settlement. A factor k denoting the ratio of the channel's width and the particle diameter was defined. The terminal settling velocity for a single particle is inversely proportional to k, and the time that the particle takes to reach the terminal velocity is positively related to k. When k is greater than 15, the channel width's effects are negligible. For dual particles of the same size, the drafting-kissing-tumbling (DKT) process occurs infinitely in a periodic pattern, with the two particles swapping positions and settling around the channel's centerline. The smaller the k, the sooner the DKT process occurs. The particles collide with the channel wall when k <= 10. For dual particles of different sizes, the DKT process occurs once so that the bigger particle leads the settlement. Both particles settle along the channel's centerline in a steady state. The bigger the k, the bigger the difference in their terminal settling velocities until k = 15. The small particle collides with the channel wall if released under the big particle when k = 6. The findings of this study are expected to inform channeling or pipeline design in relevant engineering practices.

A Survey of Human-Computer Interaction Technology in Intelligent Home for Children's Learning

The development of the COVID-19 epidemic has increased the home learning time of children. More researchers began to pay attention to children's learning in home. This survey reviewed the frontier and classic cases in the field of interactive design of children's home learning in the past five years, analyzed tangible user interface, augmented reality, and multimodal interaction in human-computer interaction of children's home learning. This paper reviewed the application of interactive system in children's learning and points out its positive side in development of ability, process of learning, habits of learning, and environment of learning of children. Through analysis, we advise that it is necessary to create home learning applications, link smart home systems, and build an interactive learning environment for smart home learning environment design. Finally, we point out the technical and ethical problems existing in the current research, proposes that intelligent perception, emotion recognition, and expression technologies should be introduced in the future, and looks forward to the development of this field. © 2023 Institute of Computing Technology. All rights reserved.

Messenger RNA Nanovaccine in Cancer Immunotherapy

During the past 2 years, messenger RNA (mRNA) nanovaccine has shown its remarkable antiviral efficacy, rapid manufacture, and good safety profile for preventing coronavirus infection. Meanwhile, intracellular delivery of mRNA-based cancer vaccine starts to show great potential to elicit antitumor immunity. mRNA encoding tumor antigens, delivery vehicles, and immune adjuvants are the key components of mRNA cancer vaccine. To achieve robust antitumor efficacy, mRNA encoding tumor antigens need to be efficiently delivered and translated in dendritic cells with concurrent innate immune stimulation to promote antigen presentation. Compared with other types of tumor vaccines, mRNA nanovaccine is featured by efficient antigen expression, high potential for rapid development, low-cost manufacture, and safe administration. In this chapter, we mainly focus on the mRNA synthesis, mRNA modification, delivery vectors with immune-stimulating features, and tumor antigen selection and discuss the future direction of mRNA nanovaccine in cancer immunotherapy. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023.

Thermal stability of diagnostic targets plasmodium falciparum histidine rich protein II and plasmodium lactate dehydrogenase in rapid detection.

During the COVID-19 epidemic, blood samples are usually processed at 56 to attenuate the virus before pathogen detection. 71 blood samples of malaria patients reported by Shanghai Center for Disease Control and Prevention in 2017-2019 were collected, including 38 with Plasmodium falciparum infection, 8 P. malariae, 11 P. ovale and 14 P. vivax. The effect of inactivation on the thermal stability of P. falciparum histidine rich protein II (PfHRPII) and Plasmodium lactate dehydrogenase (pLDH) in blood samples was assessed before and after incubation at 56 for 30 min using the rapid diagnostic test (RDT) kit. The results showed that among the 38 P. falciparum T1-positive (PfHRPII) blood samples before heat treatment, 35 samples remained to be T1-positive (92.11%, 35/38, chi2=3.123, P>0.05) after heat treatment;while 54 blood samples (26 P. falciparum, 6 P. vivax, 10 P. ovale and 12 P. vivax) that were T2-positive (pLDH) before heat treatment turned to be T2-negative (positive rate 0, 0/54, chi2=87.755, P<0.01) after heat treatment. It was demonstrated that PfHRPII is stable during incubation at 56 for 30 min, while pLDH is unstable and degraded or inactivated during the heating. Therefore, the detection results of P. falciparum will not be affected by RDT, but diagnosis of the parasites other than P. falciparum in blood samples may be missed.Copyright © 2021, National Institute of Parasitic Diseases. All rights reserved.

Uncovering the Dynamics of Consumption-Based Household Water Footprint in Response to Pandemic: The Hysteresis Effect of Disruption

The socioeconomic disruption of COVID-19 has strong implications for water management. However, it remains unclear how water use related to urban and rural household consumption responded to the outbreak. Taking 15 provincial regions in China for a case study, we quantified the variations of consumption-based household water footprint induced by the first outbreak of the pandemic and tracked the responsive changes of interregional virtual water flows and control relationships. We found in many regions, the most drastic change occurred only a quarter after the major outbreak, when the average water footprint of urban and rural households decreased by 13% and 9%, respectively. This indicates the presence of a hysteretic effect of disruption to household expenditures. With the subsequent recovery of household consumption, the water footprints in many regions rebounded and even surpassed the historical values. Guangdong had a fast rebound in its net virtual water inflow related to urban households because of the fast recovery of its manufacturing and services activities. The pandemic-related water footprint dynamics suggest not only the necessity of timely managing supply chains to prevent shortage of water and water-intensive products, but also the importance of fostering consumption adjustments for conserving water in a post-pandemic era. © 2023 The Authors. Earth's Future published by Wiley Periodicals LLC on behalf of American Geophysical Union.

COVID-19 image classification based on Deep Learning

COVID-19 is diagnosed by nucleic acid testing, aided by Computed Tomography. In order to rapidly screen CT images of COVID-19, Squeeze-And-Excitation Network based network model combined with Deep Learning is proposed, which can adapt to learn important parts of the feature channel. Firstly, the feature Squeeze is carried out along the space dimension, and the output dimension matches the number of input feature channels. Secondly, the feature channel learns the feature channel characteristics by capturing the channel dependencies in the previous step. Finally, the weight is updated to model the correlation of feature channels. The Precision, Recall and Specificity were selected to be 92.8%, 92.8% and 93.7%, the Accuracy of the model was 93.24% for the whole sample specificity. Compared with the mainstream model, the experimental results of this model are improved greatly. © 2022 ACM.

Policy entrepreneurs and individuals: Influence and behavior in pandemic response

Policy entrepreneurs have traditionally been recognized for their ability to influence policymakers by framing policy problems and pairing them with preferred solutions. Does their influence extend to the public? We examine this question in the context of the COVID-19 pandemic in the United States. We analyze whether an individual's perception of a visible, national-level policy entrepreneur, director of the National Institute of Allergy and Infectious Diseases (NIAID) Dr. Anthony Fauci, influences their perceived risk of contracting the virus and their uptake of recommended COVID-19 risk mitigation behaviors. Findings indicate that approval of Dr. Fauci predicts individual risk perceptions and uptake of mask wearing practices, with his influence particularly strong among conservatives. However, Dr. Fauci's influence as a policy entrepreneur waned over time and was moderated by a host of factors such as an individual's worldview, perceptions of policy environment, and media consumption.

Getting to Zero: Achievement of 95-95-95 and Declining Hiv Incidence in Eswatini

Background: Achieving UNAIDS global 95 targets among people living with HIV (PLHIV) is key to HIV epidemic control. Eswatini, a country with one of the severest HIV epidemics, has implemented an aggressive national HIV response with comprehensive HIV prevention and treatment services. We assessed progress towards these targets in the high HIV disease burden setting of Eswatini. Method(s): We compared 95-95-95 indicators and HIV incidence from two sequential Population-based HIV Impact Assessment (PHIA) surveys conducted in Eswatini in 2016 and 2021. These PHIAs were similarly designed as nationally representative household surveys among individuals 15 years and older. Respondents completed interviews and provided blood samples for HIV rapid testing (Determine and Unigold), antiretrovirals (ARV) testing, and viral load (VL) measurement. The first 95 (diagnosed PLHIV) was assessed by self-report or detectable ARVs;second 95 (on treatment) by self-report or detectable ARVs among diagnosed PLHIV, and third 95 (VL suppression, VLS) as VL < 1,000 copies/mL among PLHIV on treatment. Annual HIV incidence was estimated from recent infections (classified by HIV-1 LAg avidity assay, VL and ARV detection) using the formula recommended by the World Health Organization Incidence Working Group. Survey weights accounting for sample selection probabilities and adjusted for nonresponse and noncoverage were applied. Result(s): The 11,199 adults in the 2021 PHIA were at 94-97-96, while the 10,934 adults in the 2016 PHIA were at 87-89-91, a statistically significant increase of 5-10% in all 95 indicators (see Table). Target achievement varied by sex, but all 95 indicators improved among men (92-96-97 in 2021 vs 80-90-91 in 2016) and women (95-98-96 in 2021 vs 91-88-91 in 2016). Overall annual HIV incidence declined by 45% from 1.13% in 2016 to 0.62% in 2021 (p = 0.055). Annual HIV incidence in 2021 was nearly seven times higher among women (1.11%) than among men (0.17%). Conclusion(s): These findings reflect substantial progress toward HIV epidemic control, a remarkable achievement in the context of health, social and economic disruptions and challenges associated with the COVID-19 era. The 2021 data highlight remaining gaps in knowledge of HIV status, particularly among men, and HIV incidence reduction, particularly among women.

Online Chinese Teaching and Learning at Massey University in New Zealand

This chapter first provides an overview of the overall structure of the Chinese program and the development of its teaching practices at Massey University before 2015. The study then goes on to report how a new interactive and engaging online learning environment is structured and how the teaching practices are carried out based on such a system between 2016 and 2021. Students' feedback regarding the effectiveness of the course design, learning activities, and how these help to facilitate their learning and the achievement of their desired learning outcomes is also reported. Lastly, the impact of the COVID-19 on students' learning and future improvements are also briefly discussed. © The Editor(s) (if applicable) and The Author(s), under exclusive licence to Springer Nature Switzerland AG 2022.

"Are you me?": understanding the political potential of feminist identity spaces on Reddit during the COVID-19 pandemic

In this study we performed a critical discourse analysis of the r/workingmoms subreddit during the early days of the COVID-19 pandemic (March-May 2020). Using this data we argue that Reddit's platform can facilitate what we schematize as feminist "identity spaces." We use the heuristic of "spaces" rather than "networks" or "online communities" and connect this theorization to our understanding of the discursive work on the subreddit which facilitates in-group communication and situated structural critique. However, we also interrogate the political possibilities of identity spaces and understand them as a symptom of what Angela McRobbie has called "the cultural politics of disarticulation." Ultimately, we argue that the same platform affordances that allow for identity spaces to thrive also limit their political potency and we frame this within Lauren Berlant's theorization of "cruel optimism."

Data-Driven COVID-19 Vaccine Development for Janssen

The COVID-19 pandemic has spurred extensive vaccine research worldwide. One crucial part of vaccine development is the phase III clinical trial that assesses the vaccine for safety and efficacy in the prevention of COVID-19. In this work, we enumerate the first successful implementation of using machine learning models to accelerate phase III vaccine trials, working with the single-dose Johnson & Johnson vaccine to predictively select trial sites with naturally high incidence rates ("hotspots"). We develop DELPHI, a novel, accurate, policy-driven machine learning model that serves as the basis of our predictions. During the second half of 2020, the DELPHI-driven site selection identified hotspots with more than 90% accuracy, shortened trial duration by six to eight weeks (approximately 33%), and reduced enrollment by 15,000 (approximately 25%). In turn, this accelerated time to market enabled Janssen's vaccine to receive its emergency use authorization and realize its public health impact earlier than expected. Several geographies identified by DELPHI have since been the first areas to report variants of concern (e.g., Omicron in South Africa), and thus DELPHI's choice of these areas also produced early data on how the vaccine responds to new threats. Johnson & Johnson has also implemented a similar approach across its business including supporting trial site selection for other vaccine programs, modeling surgical procedure demand for its Medical Device unit, and providing guidance on return-to-work programs for its 130,000 employees. Continued application of this methodology can help shorten clinical development and change the economics of drug development by reducing the level of risk and cost associated with investing in novel therapies. This will allow Johnson & Johnson and others to enable more effective delivery of medicines to patients.

Clinical features of severe acute respiratory syndrome coronavirus-2 Omicron variant infection in mother-infant dyads during lactation

Objective To summarize the clinical features, viral load changes, and outcomes of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Omicron variant infection in mother-infant dyads during lactation period. Methods A total of 24 pairs of lactating mothers and infants under one year old who were infected with SARS-CoV-2 and hospitalized in Lingang Branch of Shanghai Sixth People's Hospital from April 8 to May 30, 2022, were selected as the lactation group in this retrospective study. Another 24 non-lactating mothers, with children of one to three years old, who matched with those mothers in the lactation group in clinical classification and admission date were selected as the control group. Vaccination status, clinical symptoms, daily cycle threshold (Ct) of open reading frame 1ab (ORF1ab) gene and nucleocapsid protein (N) gene, and the duration of positive nucleic acid test were compared between the groups and were analyzed using two independent samples t test, one-way analysis of variance, LSD test, and Chi-square test. Results Among the 24 infants in the lactation group with an age of (6.5±2.1) months, 23 cases were mild type, one was common, and none had been vaccinated against SARS-CoV-2. The maternal age of the lactation and the control group did not differ statistically [(28.7±6.4) vs (28.2±5.2) years, t=0.30, P=0.768]. Mothers with mild type accounted for 88% (21/24) and those with common for 12% (3/24) in both groups of mothers. Three mothers received one dose of vaccine and two received two in the lactation group, while three received one dose and three received two in the control group [21%(5/24) vs 25%(6/24), χ2=0.12, P=0.731]. The most common symptoms of lactating infants were fever (100%, 24/24), followed by diarrhea (58%, 14/24), cough (50%, 12/24), and wheeze (29%, 7/24), those of the lactating mothers were fever (75%, 18/24), cough (75%, 18/24), and sore throat (63%, 15/24), while those of non-lactating mothers were cough (88%, 21/ 24), sore throat (71%, 17/24), and fever (58%, 14/24). The duration of positive nucleic acid test was the shortest in the lactating infants [(9.2±2.1) d (5-14 d)], followed by mothers in the control group [(11.2± 2.4) d (6-16 d)] and mothers in the lactation group [(14.0±4.2) d (8-26 d)] (LSD test, all P<0.05). Each day from day 2 to 9 after diagnosis, Ct values of nucleic acid of infants in the lactation group were all higher than those of mothers in both the lactation and control groups (LSD test, all P<0.05). On day 10, Ct value of nucleic acid infants was higher than that in mothers in the lactation group (ORF1ab gene: 37.91±4.34 vs 32.79±5.47;N gene: 37.95±4.58 vs 32.66±5.77), which was lower than those in mothers in the control group (ORF1ab gene: 32.79±5.47 vs 35.90±4.17;N gene: 32.66±5.77 vs 36.08±4.16) (LSD test, all P< 0.05). On day 11, the nucleic acid Ct values of mothers in the lactation group were all lower than those in the control group (ORF1ab gene: 35.03±3.74 vs 37.84±3.26, t=－2.78, P=0.008;N gene: 35.30±3.75 vs 38.11±2.90, t=－2.90, P=0.006). On day 12, Ct value of ORF1ab gene and N gene in mothers in the lactation group were similar to those in mothers in the control group (both P>0.05). Conclusions The SARS-CoV-2 vaccination rate of mothers and infants were low during lactation. Lactating infants infected with SARS-CoV-2 Omicron variant have low virus load and may have a quick recovery, while for the lactating mothers, the virus load is high and the recovery is slow. © 2022 Chinese Medical Journals Publishing House Co.Ltd. All rights reserved.

A Medical Device That Can Be Used for Psychotherapy in the Metaverse

In 2020, a new coronavirus swept the world, and the advent of this disease has a huge impact on our social and economic development. Due to the limited medical resources and regional differences, this model of virtual medicine becomes more valuable. In this paper, we create a virtual medical space based on a metaverse in order to investigate whether the medical model can be freely transformed between virtual and reality. In this process, I first describe different scenarios of virtual medical care in mixed reality, and then we use one of them as an example to develop a medical device. Then we designed the software and hardware of the product and performed the user experience, it includes the interaction and usage scenarios that affect the user. Finally, this medical device will be demonstrated by user experience and feedback. © 2023 The authors and IOS Press.

Scenic Beauty Evaluation of Forests with Autumn-Colored Leaves from Aerial and Ground Perspectives: A Case Study in Qixia Mountain in Nanjing, China

In recent years, on-site visitation has been strictly restricted in many scenic areas due to the global spread of the COVID-19 pandemic. "Cloud tourism”, also called online travel, uses high-resolution photographs taken by unmanned aerial vehicles (UAVs) as the dominant data source and has attracted much attention. Due to the differences between ground and aerial observation perspectives, the landscape elements that affect the beauty of colored-leaved forests are quite different. In this paper, Qixia National Forest Park in Nanjing, China, was chosen as the case study area, and the best viewpoints were selected by combining tourists' preferred viewing routes with a field survey, followed by a scenic beauty evaluation (SBE) of the forests with autumn-colored leaves in 2021 from the aerial and ground perspectives. The results show that (1) the best viewpoints can be obtained through the spatial overlay of five landscape factors: elevation, surface runoff, slope, aspect, and distance from the road;(2) the dominant factors influencing the beauty of colored-leaved forests from the aerial perspective are terrain changes, forest coverage, landscape composition, landscape contrast, the condition of the human landscape, and recreation frequency;and (3) the beauty of the ground perspective of the colored-leaved forests is strongly influenced by the average diameter at breast height (DBH), the dominant color of the leaves, the ratio of the colored-leaved tree species, the canopy width, and the fallen leaf coverage. The research results can provide scientific reference for the creation of management measures for forests with autumn-colored leaves. © 2023 by the authors.

Early antiviral therapy of abidol combined with lopinavir/ritonavir and recombinant interferon alpha-2b for patients with COVID-19 in Zhejiang: A multicenter prospective study.

Objective: To compare the efficacy of the combination of abidol, lopinavir/ritonavir plus recombinant interferon alpha-2b (rIFNalpha-2b) and the combination of lopinavir/ritonavir plus rIFNalpha-2b for patients with COVID-19 in Zhejiang province. Method(s): A multicenter prospective study was carried out to compare the efficacy of triple combination antiviral therapy and dual combination antiviral therapy in 15 medical institutions of Zhejiang province during January 22 to February 16, 2020. All patients were treated with rIFNalpha-2b (5 million U, 2 times/d) aerosol inhalation, in addition 196 patients were treated with abidol (200 mg, 3 times/d) + lopinavir/ritonavir (2 tablets, 1 time/12 h) (triple combination group) and 41 patients were treated with lopinavir/ritonavir (2 tablets, 1 time/12 h) (dual combination group). The patients who received triple combination antiviral therapy were further divided into three subgroups: <48 h, 3-5 d and >5 d according the time from the symptom onset to medication starting. The therapeutic efficacy was compared between triple combination group and dual combination group, and compared among 3 subgroups of patients receiving triple combination antiviral therapy. SPSS 17.0 software was used to analyze the data. Result(s): The virus nucleic acid-negative conversion time in respiratory tract specimens was (12.2+/-4.7) d in the triple combination group, which was shorter than that in the dual combination group [(15.0+/-5.0) d] (t=6.159, P<0.01). The length of hospital stay in the triple combination group [12.0 (9.0, 17.0) d] was also shorter than that in the dual combination group [15.0 (10.0, 18.0) d] (H=2.073, P<0.05). Compared with the antiviral treatment which was started within after the symptom onset of in the triple combination group, the time from the symptom onset to the viral negative conversion was 13.0 (10.0, 17.0), 17.0 (13.0, 22.0) and 21.0 (18.0, 24.0) d in subgroups of 48 h, 3-5 d and >5 d, respectively (Z=32.983, P<0.01), while the time from antiviral therapy to viral negative conversion was (11.8+/-3.9), (13.5+/-5.1) and (11.2+/-4.3) d, respectively(Z=6.722, P<0.05). Conclusion(s): The triple combination antiviral therapy of abidol, lopinavir/litonavir and rIFNalpha-2b shows shorter viral shedding time and shorter hospitalization time, compared with the dual combination antiviral therapy;and the earlier starting triple combination antiviral therapy will result in better antiviral efficacy.Copyright © 2020 by the Chinese Medical Association.

Qualitative study on psychological experience of close contacts with covid-19 during the centralized isolation medical observation period

To analyze the psychological experience of close contacts with COVID-19 during the centralized isolation medical observation (centralized isolation for short) period, 17 close contacts of COVID-19 who received medical isolation observation at designated locations in a city of China were selected by purposive sampling using qualitative study methods, and the interviewees were interviewed by full-coverage structured telephone. By analyzing the obtained data and summarizing the themes, it was found that the psychological status of the COVID-19 close contacts during the centralized isolation period could be classified into three themes: Obvious negative emotions, somatization of psychological problems, and demand for social support. During the epidemic, when close contacts were quarantined as high-risk groups, they often had complex and difficult psychological experiences. Relevant departments should actively carry out online guidance channels and offline knowledge dissemination, actively conduct psychological interventions for close contacts, assist them to develop life plans to enrich the life of the centralized isolation period. At the same time, relevant departments should do a good job in logistics and life support services, create a comfortable isolated living environment, and effectively relieve the negative emotions of close contacts of COVID-19 during centralized isolation through a variety of positive and effective measures to ensure physical and mental health. © 2023, Editorial department of Chinese Medical Ethics. All rights reserved.

Analysis of 2021 COVID-19 Outbreak and Vaccination in Taiwan Using a Causal Loop Diagram Approach

After nearly COVID-19 pandemic-mitigation success of 2020, Taiwan experienced its first major domestic outbreak in mid-May, 2021. Taiwan entered a nation-wide level 3 epidemic warning, one step away from a potential national lockdown, on May 19, 2021. Systems thinking is an effective tool to help policymakers better understand the complex COVID-19 crisis. This chapter applies causal loop diagrams to depict the causal connections among different components of the COVID-19 infection and immunization system in Taiwan, including vaccine shortage and hesitancy, medical health resource, and prevention and control measures responding to the COVID-19 outbreak during 2021. First, we described temporal and spatial characteristics of 2021 outbreak and the implementation of control measures in response to this outbreak from Taiwan's Central Epidemic Command Center. Then, we used causal loop diagrams to illustrate the relationship between vaccination and infections how changes in one component potentially affecting the status of the immunization system during a COVID-19 outbreak. © TheEditor(s) (ifapplicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021, 2022.

How Videoconferencing and its Affordances Transformed Teaching in Schools During COVID-19 Pandemic

The COVID-19 pandemic has brought about major changes in digitization in many areas of life and professions. New areas were digitized almost overnight, the school system in Germany was no exception leading to a demand for videoconferencing tools and communication platforms. These technologies have many different functionalities that need to be discovered, explored, and exploited by the user. Given the disruptive events that the COVID pandemic brought to us, this paper aims to shed light on how the dynamics of discovery, exploration, and exploitation unfolds. We use a functional affordance theory perspective to analyze and understand how user learn to use new technologies. To do this, we conducted an exploratory case-study-based research design including interviews with teachers from various schools to analyze how they appropriate new technologies to develop an explanatory theoretical model. © 2023 IEEE Computer Society. All rights reserved.

A DISCRETE STATE-STRUCTURED MODEL ON NETWORKS WITH TWO TRANSMISSION MODES: GLOBAL DYNAMICS ANALYSIS

In this paper, we formulate and analyze a class of discrete state-structured epidemic models that spread through both horizontal and vertical transmissions on networks, where infected individuals can move from one infected state to any other state so that our models include all possible state-transfers (disease deterioration and amelioration) among different states. Many epidemic transmissions with or without vertical transmission in nature can be analyzed by referring to our models, such as HIV-1, viral hepatitis, and Covid-19. We derive the basic reproduction number R0= Rh+ Rv, and prove that the global dynamics are completely determined by the basic reproduction number: if R0 ≤ 1, the disease-free equilibrium is globally asymptotically stable and the disease always dies out;if R0 > 1, the disease-free equilibrium is unstable, and there exists a unique endemic equilibrium that is globally asymptotically stable, and the disease persists at a positive level in the population. It also implies that vertical transmission has an impact on maintaining infectious diseases when horizontal transmission cannot sustain the disease on its own. The proof of global stability is based on the graph-theoretic approach and answer the open problem left in [1]. Finally, numerical simulations are performed to illustrate the theoretical results. © 2023 American Institute of Mathematical Sciences. All rights reserved.