scholarly journals Modelling the effect of the interaction between vaccination and non-pharmaceutical measures on COVID-19 incidence

2021 ◽  
Author(s):  
Atsegine Canga ◽  
Gorka Bidegain
Keyword(s):  
Initial Phase ◽  
Initial Conditions ◽  
Disease Incidence ◽  
Virus Transmission ◽  
Model Performance ◽  
Vaccination Rate ◽  
Protection Measure ◽  
Protection Measures ◽  
Vaccine Type ◽  
Limited Supply

Since December 2019, the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread rapidly from Wuhan (China) across the globe, affecting more than 200 countries by mid-2021, with over 190 M reported cases and around 4 M fatalities. During the first year of the pandemic, affected countries implemented a variety of non-pharmaceutical interventions to control virus transmission. In December 2020, countries started administering several authorised vaccines under a limited supply scenario. In this context, a SEIR-type continuous-time deterministic disease model was developed to explore the effect of vaccination in terms of vaccination rate and efficacy, together with varying non-pharmaceutical protection measures, on disease incidence in the initial phase of vaccination. For this, the model incorporates (i) a protection measure including low (self-protection), medium (mobility limitation), high (closure of indoor facilities) and very high (lockdown) protection levels, (ii) quarantine for confirmed cases, and (iii) vaccination rate and efficacy of four type of vaccines (Pfizer, Moderna, Astra Zeneca or Janssen). The model was verified and evaluated using the response timeline and vaccination strategies and rates in the Basque Country (N. Spain). Once the model performance was validated, different initial phase (when 30% of the population is vaccinated) vaccination scenarios were simulated, including (i) a realistic vaccine limited supply scenario, and (ii) four potential full vaccine supply scenarios where a unique vaccine type is administered. The Pfizer scenario resulted in the lowest prevalence of infection and cumulative mortality, particularly for low- and medium-level protection rates. However, regardless of the administered vaccine, a high-level protection scenario is the most effective to control the virus transmission and disease mortality in the studied initial phase of vaccination. The model here, which is based on this example, could be easily applied to other regions or countries, modifying the strategies implemented and initial conditions.

A qualitative exploration of parental perceptions regarding children’s sun exposure, sun protection, and sunburn

2020 ◽  
Author(s):  
Karlijn Thoonen ◽  
Liesbeth van Osch ◽  
Rowan Drittij ◽  
Hein de Vries ◽  
Francine Schneider
Keyword(s):  
Skin Cancer ◽  
Sun Exposure ◽  
Structured Interview ◽  
Sun Protection ◽  
Parental Perceptions ◽  
Skin Cancer Prevention ◽  
Protection Measure ◽  
Sun Safety ◽  
Protection Measures ◽  
Lack Of Knowledge

Sun protection among children is of utmost importance since sunburn in early life is a major risk factor for skin cancer development. Because parents play a vital role in enhancing sun safety among children, this study explored parental perceptions concerning sun exposure, sun protection behaviors, and sunburn in children. Additionally, the context in which children experience sunburn in order to assist the development, optimization, and targeting of sun safety interventions for parents is revealed.A qualitative study design, using a semi-structured interview guide addressing several themes (e.g. sun exposure, sun protection, and sunburn experiences), was used. Data were collected in the Netherlands in the fall of 2019. Parents were recruited via purposive sampling at schools, youth services centers, and social media. In total, 26 interviews were performed. Execution, transcription, and coding of the interviews was done by two researchers, using the qualitative analyzing program Nvivo (interrater reliability of d =.84). Comprehensive findings concerning various themes were retrieved. It was found that sunburn was frequently prevalent among children, even though all parents reported using at least one sun protection measure. Parents were often unaware of their child’s sunburn and its severity. Regarding sun protection measures, parents demonstrated an overreliance on sunscreen, often failing to adequately protect their children’s skin. Water-related activities, a lack of shade, and lack of knowledge regarding UV-index were often related to sunburn. Moreover, unexpected sun exposure or longer exposure duration than initially planned were reported as challenging situations. The majority of parents had positive perceptions regarding tanned skin for both themselves as for children.This study provides directions for future skin cancer prevention efforts targeted at both parents and their children. Since a lack of knowledge regarding sufficient sun protection measures and sunburn occurrence in various situations was reported, educational efforts are warranted. Additionally, focusing on clothing, shade-seeking, and adequate sunscreen use is recommended to increase children’s sun safety. By intervening in the physical environment as well (e.g. providing shady areas), sun protection barriers can be reduced. Lastly, the general positive attitude toward tanned skin evident in this study is certainly worthy of attention in future interventions.

scholarly journals Simple mathematical models for controlling COVID-19 transmission through social distancing and community awareness

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ahmed S. Elgazzar
Keyword(s):  
Mathematical Models ◽  
Virus Transmission ◽  
Small World ◽  
Vaccination Rate ◽  
The Novel ◽  
Social Distancing ◽  
Community Awareness ◽  
Sufficient Degree ◽  
And Control

Abstract The novel COVID-19 pandemic is a current, major global health threat. Up till now, there is no fully approved pharmacological treatment or a vaccine. Also, its origin is still mysterious. In this study, simple mathematical models were employed to examine the dynamics of transmission and control of COVID-19 taking into consideration social distancing and community awareness. Both situations of homogeneous and nonhomogeneous population were considered. Based on the calculations, a sufficient degree of social distancing based on its reproductive ratio is found to be effective in controlling COVID-19, even in the absence of a vaccine. With a vaccine, social distancing minimizes the sufficient vaccination rate to control the disease. Community awareness also has a great impact in eradicating the virus transmission. The model is simulated on small-world networks and the role of social distancing in controlling the infection is explained.

Respiratory protection ‒ new challenges

2021 ◽  
Vol 70 (1) ◽  
pp. 129-153
Author(s):  
Władysław Harmata ◽  
Dorota Kamionek
Keyword(s):  
Air Pollution ◽  
Particulate Matter ◽  
Personal Protective Equipment ◽  
Virus Transmission ◽  
Protective Equipment ◽  
Respiratory Protection ◽  
Protection Measures ◽  
Normative Requirements ◽  
New Challenges

The paper characterizes the problem of air pollution with smog. The possibility of SARS-CoV-2 virus transmission on particulate matter and the possibility of infection was analyzed. Individual respiratory protection measures available on the market were analyzed in terms of mass use, taking into account legal and normative requirements. Keywords: personal protective equipment, respiratory protection

scholarly journals Development of dynamic system response curve method for estimating initial conditions of conceptual hydrological models

2018 ◽  
Vol 20 (6) ◽  
pp. 1387-1400
Author(s):  
Yiqun Sun ◽  
Weimin Bao ◽  
Peng Jiang ◽  
Xuying Wang ◽  
Chengmin He ◽  
...  
Keyword(s):  
Dynamic System ◽  
Response Curve ◽  
Initial Conditions ◽  
Model Performance ◽  
System Response ◽  
Hydrological Models ◽  
Flood Prediction ◽  
Ill Posed ◽  
Value Decomposition

Abstract The dynamic system response curve (DSRC) has its origin in correcting model variables of hydrologic models to improve the accuracy of flood prediction. The DSRC method can lead to unstable performance since the least squares (LS) method, employed by DSRC to estimate the errors, often breaks down for ill-posed problems. A previous study has shown that under certain assumptions the DSRC method can be regarded as a specific form of the numerical solution of the Fredholm equation of the first kind, which is a typical ill-posed problem. This paper introduces the truncated singular value decomposition (TSVD) to propose an improved version of the DSRC method (TSVD-DSRC). The proposed method is extended to correct the initial conditions of a conceptual hydrological model. The usefulness of the proposed method is first demonstrated via a synthetic case study where both the perturbed initial conditions, the true initial conditions, and the corrected initial conditions are precisely known. Then the proposed method is used in two real basins. The results measured by two different criteria clearly demonstrate that correcting the initial conditions of hydrological models has significantly improved the model performance. Similar good results are obtained for the real case study.

scholarly journals Inconsistent strategies to spin up models in CMIP5: implications for ocean biogeochemical model performance assessment

2016 ◽  
Vol 9 (5) ◽  
pp. 1827-1851 ◽  
Author(s):  
Roland Séférian ◽  
Marion Gehlen ◽  
Laurent Bopp ◽  
Laure Resplandy ◽  
James C. Orr ◽  
...  
Keyword(s):  
Performance Assessment ◽  
Initial Conditions ◽  
Model Performance ◽  
Cmip5 Models ◽  
Biogeochemical Model ◽  
Earth System ◽  
Model Intercomparison ◽  
System Models ◽  
Marine Biogeochemistry ◽  
Earth System Models

Abstract. During the fifth phase of the Coupled Model Intercomparison Project (CMIP5) substantial efforts were made to systematically assess the skill of Earth system models. One goal was to check how realistically representative marine biogeochemical tracer distributions could be reproduced by models. In routine assessments model historical hindcasts were compared with available modern biogeochemical observations. However, these assessments considered neither how close modeled biogeochemical reservoirs were to equilibrium nor the sensitivity of model performance to initial conditions or to the spin-up protocols. Here, we explore how the large diversity in spin-up protocols used for marine biogeochemistry in CMIP5 Earth system models (ESMs) contributes to model-to-model differences in the simulated fields. We take advantage of a 500-year spin-up simulation of IPSL-CM5A-LR to quantify the influence of the spin-up protocol on model ability to reproduce relevant data fields. Amplification of biases in selected biogeochemical fields (O2, NO3, Alk-DIC) is assessed as a function of spin-up duration. We demonstrate that a relationship between spin-up duration and assessment metrics emerges from our model results and holds when confronted with a larger ensemble of CMIP5 models. This shows that drift has implications for performance assessment in addition to possibly aliasing estimates of climate change impact. Our study suggests that differences in spin-up protocols could explain a substantial part of model disparities, constituting a source of model-to-model uncertainty. This requires more attention in future model intercomparison exercises in order to provide quantitatively more correct ESM results on marine biogeochemistry and carbon cycle feedbacks.

scholarly journals Evaluating disease prediction models using a cohort whose covariate distribution differs from that of the target population

2017 ◽  
Vol 28 (1) ◽  
pp. 309-320 ◽  
Author(s):  
Scott Powers ◽  
Valerie McGuire ◽  
Leslie Bernstein ◽  
Alison J Canchola ◽  
Alice S Whittemore
Keyword(s):  
Prediction Models ◽  
Risk Model ◽  
Disease Incidence ◽  
Model Performance ◽  
Target Population ◽  
R Package ◽  
Model Assessment ◽  
Weighted Estimates ◽  
Cancer Prediction ◽  
Model Predictions

Personal predictive models for disease development play important roles in chronic disease prevention. The performance of these models is evaluated by applying them to the baseline covariates of participants in external cohort studies, with model predictions compared to subjects' subsequent disease incidence. However, the covariate distribution among participants in a validation cohort may differ from that of the population for which the model will be used. Since estimates of predictive model performance depend on the distribution of covariates among the subjects to which it is applied, such differences can cause misleading estimates of model performance in the target population. We propose a method for addressing this problem by weighting the cohort subjects to make their covariate distribution better match that of the target population. Simulations show that the method provides accurate estimates of model performance in the target population, while un-weighted estimates may not. We illustrate the method by applying it to evaluate an ovarian cancer prediction model targeted to US women, using cohort data from participants in the California Teachers Study. The methods can be implemented using open-source code for public use as the R-package RMAP (Risk Model Assessment Package) available at http://stanford.edu/~ggong/rmap/ .

scholarly journals MECHANICAL PROTECTION GUIDELINES1

1995 ◽  
Vol 1995 (1) ◽  
pp. 841-842
Author(s):  
Frank Whipple ◽  
Sharon Christopherson ◽  
Jacqueline Michel
Keyword(s):  
Cultural Sensitivity ◽  
Protection Measure ◽  
Protection Measures ◽  
Site Specific ◽  
Physical Conditions ◽  
Exchange Of Information ◽  
Shoreline Protection ◽  
National Response ◽  
Protection Strategies ◽  
Operational Constraints

ABSTRACT The recently published Mechanical Protection Guidelines will:provide guidelines for identifying and prioritizing areas of economic, environmental, and cultural sensitivity, including formats for mapping sensitive areas;describe the types of shoreline protection measures available, with emphasis on limits and requirements of each protection measure;provide guidance on developing site-specific protection strategies, including equipment and logistics needed, operational constraints, and physical conditions of the site (charts and tables are included as tools for development of the most feasible and successful strategies); andprovide continuity among area plans, to facilitate exchange of information and use by regional and national response teams.

scholarly journals Forecasting circulation in the Cilician Basin of the Levantine Sea

2006 ◽  
Vol 3 (5) ◽  
pp. 1481-1514 ◽  
Author(s):  
E. Özsoy ◽  
A. Sözer
Keyword(s):  
Boundary Conditions ◽  
Initial Conditions ◽  
Eastern Mediterranean ◽  
Model Performance ◽  
Surface Flux ◽  
Mediterranean Coast ◽  
Open Boundary ◽  
Surface Boundary ◽  
Open Boundary Conditions ◽  
Levantine Sea

Abstract. The Cilician Basin/Shelf Model is adapted for studying the shelf circulation in the Cilician Basin – Gulf of İskenderun region of the Levantine Basin of the Eastern Mediterranean between the Turkish Mediterranean coast, Syria and the island of Cyprus. The model initial conditions and open boundary conditions are supplied by the ALERMO regional model of the Levantine Sea, while interactive surface flux boundary conditions are specified by an atmospheric boundary layer sub-model using calculated water properties and surface atmospheric variables supplied by the Skiron atmospheric model, within the nested modelling approach of the MFSTEP (Mediterranean Forecasting System: Towards Environmental Predictions) project. Sensitivity tests are performed for alternative surface boundary conditions. Model performance for shelf/meso-scale forecasts is demonstrated.

scholarly journals A Mathematical Model for Nipah Virus Infection

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Assefa Denekew Zewdie ◽  
Sunita Gakkhar
Keyword(s):  
Virus Infection ◽  
Reproduction Number ◽  
Initial Conditions ◽  
Nipah Virus ◽  
Virus Transmission ◽  
Globally Asymptotically Stable ◽  
Dead Bodies ◽  
Manifold Theory ◽  
The Impact ◽  
The Given

It has been reported that unprotected contact with the dead bodies of infected individuals is a plausible way of Nipah virus transmission. An SIRD model is proposed in this paper to investigate the impact of unprotected contact with dead bodies of infected individuals before burial or cremation and their disposal rate on the dynamics of Nipah virus infection. The model is analyzed, and the reproduction number is computed. It is established that the disease-free state is globally asymptotically stable when the reproduction number is less than unity and unstable if it is greater than unity. By using the central manifold theory, we observe that the endemic equilibrium is locally stable near to unity. It is concluded that minimizing unsafe contact with the infected dead body and/or burial or cremation as fast as possible contributes positively. Further, the numerical simulations for the given choice of data and initial conditions illustrate that the endemic state is stable and the disease persists in the community when the reproduction number is greater than one.

scholarly journals Micro Sand Engine Beach Stabilization Strategy at Puerto Morelos, Mexico

2020 ◽  
Vol 8 (4) ◽  
pp. 247 ◽  
Author(s):  
Mireille Escudero ◽  
Edgar Mendoza ◽  
Rodolfo Silva
Keyword(s):  
Small Scale ◽  
Coastal Protection ◽  
Protection Measure ◽  
Morphological Response ◽  
Protection Measures ◽  
Small Bell ◽  
Waves And Currents ◽  
Maintenance Work ◽  
Negative Impacts ◽  
The Waves

In the last decade, innovative beach nourishment strategies have been developed, driven by the increased worldwide interest in environmentally friendly coastal protection measures. In this context, the massive nourishment project of the Netherlands, known as Sand Engine, begun in 2011, has been hailed as a successful means of beach protection. Continuous monitoring, field campaigns, and numerical modeling have shown that the great volume of sand deployed is gradually transported by the waves and currents along the coastline, avoiding the need for repeated invasive, small scale beach replenishments. A very small, bell-shaped Sand Engine was designed to protect the beachfront at a tourist resort near Puerto Morelos, Mexico. To estimate the morphological response of the beach and the functioning of the micro Sand Engine as a sand reservoir, XBeach numerical modelling was applied to the project. The micro Sand Engine is seen to be a sustainable and eco-friendly coastal protection measure, especially applicable when a large nourishment project is not viable. Maintenance work for the nourishment is cost and time effective, and any negative impacts to sensitive ecosystems nearby can be detected and controlled quickly.

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