scholarly journals Social Heterogeneity Drives Complex Patterns of the COVID-19 Pandemic: Insights From a Novel Stochastic Heterogeneous Epidemic Model (SHEM)

2021 ◽  
Vol 8 ◽  
Author(s):  
Alexander V. Maltsev ◽  
Michael D. Stern
Keyword(s):  
Epidemic Model ◽  
Mitigation Strategies ◽  
Vulnerable Groups ◽  
Key Factors ◽  
Key Factor ◽  
Social Heterogeneity ◽  
Complex Patterns ◽  
Spread Of Infection ◽  
Second Wave ◽  
Main Population

In addition to vaccine and impactful treatments, mitigation strategies represent an effective way to combat the COVID-19 virus and an invaluable resource in this task is numerical modeling that can reveal key factors in COVID-19 pandemic development. On the other hand, it has become evident that regional infection curves of COVID-19 exhibit complex patterns which often differ from curves predicted by forecasting models. The wide variations in attack rate observed among different social strata suggest that this may be due to social heterogeneity not accounted for by regional models. We investigated this hypothesis by developing and using a new Stochastic Heterogeneous Epidemic Model that focuses on subpopulations that are vulnerable in the sense of having an increased likelihood of spreading infection among themselves. We found that the isolation or embedding of vulnerable sub-clusters in a major population hub generated complex stochastic infection patterns which included multiple peaks and growth periods, an extended plateau, a prolonged tail, or a delayed second wave of infection. Embedded vulnerable groups became hotspots that drove infection despite efforts of the main population to socially distance, while isolated groups suffered delayed but intense infection. Amplification of infection by these hotspots facilitated transmission from one urban area to another, causing the epidemic to hopscotch in a stochastic manner to places it would not otherwise reach; whereas vaccination only in hotspot populations stopped geographic spread of infection. Our results suggest that social heterogeneity is a key factor in the formation of complex infection propagation patterns. Thus, the mitigation and vaccination of vulnerable groups is essential to control the COVID-19 pandemic worldwide. The design of our new model allows it to be applied in future studies of real-world scenarios on any scale, limited only by computing memory and the ability to determine the underlying topology and parameters.

scholarly journals Social heterogeneity drives complex patterns of the COVID-19 pandemic: insights from a novel Stochastic Heterogeneous Epidemic Model (SHEM)

2020 ◽  
Author(s):  
Alexander V. Maltsev ◽  
Michael D. Stern
Keyword(s):  
Epidemic Model ◽  
Mitigation Strategies ◽  
Vulnerable Groups ◽  
Key Factors ◽  
Future Studies ◽  
Key Factor ◽  
Social Heterogeneity ◽  
Complex Patterns ◽  
Second Wave ◽  
Main Population

AbstractIn today’s absence of a vaccine and impactful treatments, the most effective way to combat the virus is to find and implement mitigation strategies. An invaluable resource in this task is numerical modeling that can reveal key factors in COVID-19 pandemic development. On the other hand, it has become evident that regional infection curves of COVID-19 exhibit complex patterns which often differ from curves predicted by forecasting models. The wide variations in attack rate observed among different social strata suggest that this may be due to social heterogeneity not accounted for by regional models. We investigated this hypothesis by developing and using a new Stochastic Heterogeneous Epidemic Model (SHEM) that focuses on subpopulations that are vulnerable in the sense of having an increased likelihood of spreading infection among themselves. We found that the isolation or embedding of vulnerable sub-clusters in a major population hub generated complex stochastic infection patterns which included multiple peaks and growth periods, an extended plateau, a prolonged tail, or a delayed second wave of infection. Embedded vulnerable groups became hotspots that drove infection despite efforts of the main population to socially distance, while isolated groups suffered delayed but intense infection. Amplification of infection by these hotspots facilitated transmission from one urban area to another, causing the epidemic to hopscotch in a stochastic manner to places it would not otherwise reach, resembling a microcosm of the situation worldwide as of September 2020. Our results suggest that social heterogeneity is a key factor in the formation of complex infection propagation patterns. Thus, the mitigation of vulnerable groups is essential to control the COVID-19 pandemic worldwide. The design of our new model allows it to be applied in future studies of real-world scenarios on any scale, limited only by computing memory and the ability to determine the underlying topology and parameters.

scholarly journals Optimize Design of Run-Flat Tires by Simulation and Experimental Research

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 474
Author(s):  
Huaqiao Liu ◽  
Yiren Pan ◽  
Huiguang Bian ◽  
Chuansheng Wang
Keyword(s):  
Stress Distribution ◽  
Energy Loss ◽  
Successful Implementation ◽  
Performance Tests ◽  
Key Factors ◽  
Heat Accumulation ◽  
Factors Affecting ◽  
Structural Rigidity ◽  
Key Factor ◽  
Durability Testing

In this study, the two key factors affecting the thermal performance of the insert rubber and stress distribution on the tire sidewall were analyzed extensively through various performance tests and simulations to promote the development of run-flat tires. Four compounds and two structures of insert rubber were designed to investigate the effects of heat accumulation and stress distribution on durability testing at zero pressure. It was concluded that the rigidity and tensile strength of the compound were negatively correlated with temperature. The deformation was a key factor that affects energy loss, which could not be judged solely by the loss factor. The stress distribution, however, should be considered in order to avoid early damage of the tire caused by stress concentration. On the whole, the careful balance of mechanical strength, energy loss, and structural rigidity was the key to the optimal development of run-flat tires. More importantly, the successful implementation of the simulations in the study provided important and useful guidance for run-flat tire development.

scholarly journals High coverage COVID-19 mRNA vaccination rapidly controls SARS-CoV-2 transmission in long-term care facilities

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Pablo M. De Salazar ◽  
Nicholas B. Link ◽  
Karuna Lamarca ◽  
Mauricio Santillana
Keyword(s):  
Long Term Care ◽  
Mitigation Strategies ◽  
Key Factors ◽  
Modeling Framework ◽  
High Coverage ◽  
Term Care ◽  
Early Effect ◽  
Care Facilities ◽  
The Relationship

Abstract Background Residents of Long-Term Care Facilities (LTCFs) represent a major share of COVID-19 deaths worldwide. Measuring the vaccine effectiveness among the most vulnerable in these settings is essential to monitor and improve mitigation strategies. Methods We evaluate the early effect of the administration of BNT162b2-mRNA vaccine to individuals older than 64 years residing in LTCFs in Catalonia, Spain. We monitor all the SARS-CoV-2 documented infections and deaths among LTCFs residents once more than 70% of them were fully vaccinated (February–March 2021). We develop a modeling framework based on the relationship between community and LTCFs transmission during the pre-vaccination period (July–December 2020). We compute the total reduction in SARS-CoV-2 documented infections and deaths among residents of LTCFs over time, as well as the reduction in the detected transmission for all the LTCFs. We compare the true observations with the counterfactual predictions. Results We estimate that once more than 70% of the LTCFs population are fully vaccinated, 74% (58–81%, 90% CI) of COVID-19 deaths and 75% (36–86%, 90% CI) of all expected documented infections among LTCFs residents are prevented. Further, detectable transmission among LTCFs residents is reduced up to 90% (76–93%, 90% CI) relative to that expected given transmission in the community. Conclusions Our findings provide evidence that high-coverage vaccination is the most effective intervention to prevent SARS-CoV-2 transmission and death among LTCFs residents. Widespread vaccination could be a feasible avenue to control the COVID-19 pandemic conditional on key factors such as vaccine escape, roll out and coverage.

From detente to containment: the emergence of Iran's new Saudi strategy

2021 ◽  
Author(s):  
Hassan Ahmadian ◽  
Payam Mohseni
Keyword(s):  
Decision Making ◽  
Saudi Arabia ◽  
Middle East ◽  
Strategic Decision ◽  
Key Factors ◽  
Peace And Conflict ◽  
Key Factor ◽  
Decision Making Factors ◽  
Containment Strategy ◽  
The Persian Gulf

Abstract Iran's strategy with respect to Saudi Arabia is a key factor in the complex balance of power of the Middle East as the Iranian–Saudi rivalry impacts the dynamics of peace and conflict across the region from Yemen to Syria, Lebanon, Iraq and Bahrain. What is Iranian strategic thinking on Saudi Arabia? And what have been the key factors driving the evolution of Iranian strategy towards the Kingdom? In what marks a substantive shift from its previous detente policy, we argue that Tehran has developed a new containment strategy in response to the perceived threat posed by an increasingly prox-active Saudi Arabia in the post-Arab Spring period. Incorporating rich fieldwork and interviews in the Middle East, this article delineates the theoretical contours of Iranian containment and contextualizes it within the framework of the Persian Gulf security architecture, demonstrating how rational geopolitical decision-making factors based on a containment strategy, rather than the primacy of sectarianism or domestic political orientations, shape Iran's Saudi strategy. Accordingly, the article traces Iranian strategic decision-making towards the Kingdom since the Islamic Revolution of 1979 and examines three cases of Iran's current use of containment against Saudi Arabia in Syria, Yemen and Qatar.

scholarly journals Key Factors of Sustainability for Smartphones Based on Taiwanese Consumers’ Perceived Values

2018 ◽  
Vol 10 (12) ◽  
pp. 4446 ◽  
Author(s):  
Jui-Che Tu ◽  
Xiu-Yue Zhang ◽  
Sin-Yi Huang
Keyword(s):  
Service Quality ◽  
Purchase Intention ◽  
Perceived Value ◽  
Income Level ◽  
Demographic Variables ◽  
Key Factors ◽  
Significant Difference ◽  
Perceived Values ◽  
Perceived Price ◽  
Key Factor

The rapid growth of smartphones over recent decades has brought a large amount of e-waste as well as an increased carbon footprint. Facing severe environmental issues, sustainable development of smartphones has become a particularly important public concern. The main aim of this study was to clarify the key factor of sustainability for smartphones based on Taiwanese consumers’ perceived values. Apple’s iPhone was taken as an example. First, key factors of perception that smartphone consumers valued the most in terms of sustainable practice were extracted through a factor analysis. Second, demographic differences related to these key factors were investigated through t-test and one-way ANOVA analyses; demographic variables were gender, age, education level, occupation, and income level. The results were as follows: (1) the key factors were “recognition”, “brand advantage”, “service quality”, “usage period”, and “perceived price”; (2) there was a significant difference between genders on the key factors of perceived value (“recognition”, “brand advantage”, and “perceived price”). Specifically, females have higher perceived values of “recognition”, “brand advantage”, and “perceived price” than males; (3) there was a significant effect of income level on the key factor (“perceived price”) of perceived value. Specifically, respondents with an income level of NTD15,001–30,000 had a higher perceived value of “perceived price” than respondents earning NTD30,001–45,000. Among the five key factors, “recognition” and “brand advantage” are primary factors influencing purchase motivation; “recognition”, “brand advantage”, and “service quality” are primary factors that could influence brand loyalty; “perceived price” is the primary factor that affects purchase intention. This study contributes to the green market segmentation of smartphones. The limitations of the study relate to the size and distribution of the samples.

scholarly journals Symptoms, Features of Diagnosis and Preventive Measures During the “Second Wave” COVID-19 in Residents of the Kyrgyz Republic

2021 ◽  
Vol 7 (4) ◽  
pp. 164-175
Author(s):  
Sh. Sulaimanov ◽  
Zh. Esenalieva
Keyword(s):  
Large Scale ◽  
Preventive Measures ◽  
Kyrgyz Republic ◽  
Social Changes ◽  
Intellectual Work ◽  
X Ray ◽  
Coronavirus Infection ◽  
Spread Of Infection ◽  
Second Wave ◽  
Muscle Ache

The results of our study show that the respondent’s perception of large-scale social changes associated with the pandemic of the new coronavirus infection in the Kyrgyz Republic has a number of features. A sufficient level of awareness of the respondents about the symptoms of the disease, the ways of transmission of the virus, and measures to prevent the spread of infection are combined with an underestimation of the situation (17.2%). The majority (66.6%) of the respondents lived in Bishkek. The survey was held among 247 people, most of whom were women (57.3%) and young people (35.9±14.9 years). Every fourth participant in the study is a chronic tobacco smoker (24%). Less than half (47.3%) of the respondents were engaged in intellectual work. Among the respondents, the most common symptoms of COVID-19 were loss of taste or smell, fever, headache, muscle ache, cough, sore throat. Every third (28.4%) respondent was referred to an X-ray, CT scan. PCR and ELISA studies were carried out, respectively, by 22.5% and 10.9%.

scholarly journals Public Views on Priority Groups for COVID-19 Vaccination: A Survey from Iran

2021 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Najmeh Moradi ◽  
Seyyed Taghi Heydari ◽  
Leila Zarei ◽  
Jalal Arabloo ◽  
Aziz Rezapour ◽  
...  
Keyword(s):  
Online Survey ◽  
Univariate Analysis ◽  
Random Order ◽  
The Elderly ◽  
Iranian Population ◽  
Vulnerable Groups ◽  
Vaccination Programs ◽  
The Family ◽  
Key Factor ◽  
Allocation Strategies

Background: In the initial coronavirus disease 2019 (COVID-19) vaccination program, prioritizing vulnerable groups is inevitable due to limited supply. Currently, most of the allocation strategies are focused on individuals’ characteristics. Objectives: The present study aimed to assess the opinions of Iranian population in specifying high-priority individuals and groups for COVID-19 vaccination. Methods: An online survey was conducted using some popular social media in Iran. The data was collected from Iranian population (878 individuals) aged 18 years and older during the COVID-19 pandemic (2 - 20 May 2020) to investigate their opinions towards vaccine allocation strategies at the family and society levels. In vaccine prioritizing within family three option and in vaccine prioritizing within society, seven population groups were introduced by the respondents in a random order, respectively. To analyze the data, mean rank and univariate analysis was used. Results: Healthcare workers, high-risk patients, and the elderly were the first priority groups for a vaccination with a mean rank of 2.8, 2.8, and 3.8, respectively. The least priority group was policymakers and executive managers (mean rank = 5.75). At the family level, 64% of the respondents introduced one of the family members as the first priority for vaccination, followed by their children (29%) and themselves (7%). No significant relationship was observed between respondents’ characteristics and their prioritization in vaccine prioritizing within society. Conclusions: Although involving public preference in decision-making is a key factor for the success of policies, careful design and implementation of vaccination programs through considering risk-benefit assessment is strongly recommended.

scholarly journals Relative contribution of leaving home for work or education, transport, shopping and other activities on risk of acquiring COVID-19 infection outside the household in the second wave of the pandemic in England and Wales

2021 ◽  
Author(s):  
S Hoskins ◽  
S Beale ◽  
RW Aldridge ◽  
AMD Navaratnam ◽  
C Smith ◽  
...  
Keyword(s):  
Public Transport ◽  
Risk Groups ◽  
Mitigation Strategies ◽  
Or Education ◽  
Leaving Home ◽  
Household Transmission ◽  
Increased Risk ◽  
Wide Range ◽  
Household Activities ◽  
Second Wave

AbstractBackgroundWith the potential for and emergence of new COVID-19 variants, such as the reportedly more infectious Omicron, and their potential to escape the existing vaccines, understanding the relative importance of which non-household activities increase risk of acquisition of COVID-19 infection is vital to inform mitigation strategies.MethodsWithin an adult subset of the Virus Watch community cohort study, we sought to identify which non-household activities increased risk of acquisition of COVID-19 infection and which accounted for the greatest proportion of non-household acquired COVID-19 infections during the second wave of the pandemic. Among participants who were undertaking antibody tests and self-reporting PCR and lateral flow tests taken through the national testing programme, we identified those who were thought to be infected outside the household during the second wave of the pandemic. We used exposure data on attending work, using public or shared transport, using shops and other non-household activities taken from monthly surveys during the second wave of the pandemic. We used multivariable logistic regression models to assess the relative independent contribution of these exposures on risk of acquiring infection outside the household. We calculated Adjusted Population Attributable Fractions (APAF - the proportion of non-household transmission in the cohort thought to be attributable to each exposure) based on odds ratios and frequency of exposure in cases.ResultsBased on analysis of 10475 adult participants including 874 infections acquired outside the household, infection was independently associated with: leaving home for work (AOR 1.20 (1.02 – 1.42) p=0.0307, APAF 6.9%); public transport use (AOR for use more than once per week 1.82 (1.49 – 2.23) p<0.0001, APAF for public transport 12.42%); and shopping (AOR for shopping more than once per week 1.69 (1.29 – 2.21) P=0.0003, APAF for shopping 34.56%). Other non-household activities such as use of hospitality and leisure venues were rare due to restrictions and there were no significant associations with infection risk.ConclusionsA high proportion of the second wave of the pandemic was spent under conditions where people were being advised to work from home where possible, and to minimize exposure to shops, and a wide range of other businesses were subject to severe restrictions. Vaccines were being rolled out to high-risk groups. During this time, going to work was an important risk factor for infection but public transport use likely accounted for a lot of this risk. Only a minority of the cohort left home for work or used public or shared transport. By contrast, the majority of participants visited shops and this activity accounted for about one-third of non-household transmission.

scholarly journals Why We Go Where We Go: Profiling User Decisions on Choosing POIs

2020 ◽  
Author(s):  
Renjun Hu ◽  
Xinjiang Lu ◽  
Chuanren Liu ◽  
Yanyan Li ◽  
Hao Liu ◽  
...  
Keyword(s):  
Key Factors ◽  
Real World Data ◽  
Decision Factors ◽  
Point Of Interest ◽  
Learning Factor ◽  
Poi Recommendation ◽  
Key Factor ◽  
Selection Of ◽  
Decision Structures

While Point-of-Interest (POI) recommendation has been a popular topic of study for some time, little progress has been made for understanding why and how people make their decisions for the selection of POIs. To this end, in this paper, we propose a user decision profiling framework, named PROUD, which can identify the key factors in people's decisions on choosing POIs. Specifically, we treat each user decision as a set of factors and provide a method for learning factor embeddings. A unique perspective of our approach is to identify key factors, while preserving decision structures seamlessly, via a novel scalar projection maximization objective. Exactly solving the objective is non-trivial due to a sparsity constraint. To address this, our PROUD adopts a self projection attention and an L2 regularized sparse activation to directly estimate the likelihood of each factor to be a key factor. Finally, extensive experiments on real-world data validate the advantage of PROUD in preserving user decision structures. Also, our case study indicates that the identified key decision factors can help us to provide more interpretable recommendations and analyses.

scholarly journals Restarting elective endoscopy safely amidst an evolving pandemic and the impact of patient perception

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Christopher Nguyen ◽  
Kevin T. Kline ◽  
Shehzad Merwat ◽  
Sheharyar Merwat ◽  
Gurinder Luthra ◽  
...  
Keyword(s):  
Risk Mitigation ◽  
Mitigation Strategies ◽  
Transmission Risk ◽  
Dynamic Monitoring ◽  
Successful Model ◽  
Outpatient Procedures ◽  
Risk Patients ◽  
Risk Mitigation Strategies ◽  
Spread Of Infection ◽  
The Impact

Abstract Background The COVID-19 pandemic has led to disruptions in elective and outpatient procedures. Guidance from the Centers for Medicare and Medicaid Services provided a framework for gradual reopening of outpatient clinical operations. As the infrastructure to restart endoscopy has been more clearly described, patient concerns regarding viral transmission during the procedure have been identified. Moreover, the efficacy of the measures in preventing transmission have not been clearly delineated. Methods We identified patients with pandemic-related procedure cancellations from 3/16/2020 to 4/20/2020. Patients were stratified into tier groups (1–4) by urgency. Procedures were performed using our hospital risk mitigation strategies to minimize transmission risk. Patients who subsequently developed symptoms or tested for COVID-19 were recorded. Results Among patients requiring emergent procedures, 57.14% could be scheduled at their originally intended interval. COVID-19 concerns represented the most common rescheduling barrier. No patients who underwent post-procedure testing were positive for COVID-19. No cases of endoscopy staff transmission were identified. Conclusions Non-COVID-19 related patient care during the pandemic is a challenging process that evolved with the spread of infection, requiring dynamic monitoring and protocol optimization. We describe our successful model for reopening endoscopy suites using a tier-based system for safe reintroduction of elective procedures while minimizing transmission to patients and staff. Important barriers included financial and transmission concerns that need to be addressed to enable the return to pre-pandemic utilization of elective endoscopic procedures.

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