scholarly journals Effects of Various Policy Options on COVID-19 Cases in Nova Scotia including Vaccination Rollout Schedule: A Modelling Study

2021 ◽  
Author(s):  
Melissa Gillis ◽  
Ahmed Saif ◽  
Matthew Murphy ◽  
Noreen Kamal
Keyword(s):  
Nova Scotia ◽  
Herd Immunity ◽  
Age Distribution ◽  
Policy Options ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Seir Model ◽  
Policy Interventions ◽  
Co Morbidity ◽  
Roll Out

Background: The COVID-19 pandemic presents a significant challenge to minimize mortality and hospitalizations due to this disease. Vaccinations have begun to roll-out; however, restriction policies required during and after the rollout remain uncertain. A susceptible-exposed-infected-recovered (SEIR) model was developed for Nova Scotia, and it accounted for the province's policy interventions, demographics, and vaccine rollout schedule. Methods: A modified SEIR model was developed to simulate the spread and outcomes from COVID-19 in Nova Scotia under different policy options. The model incorporated the age distribution and co-morbidity of the province. A system dynamics model was developed in Vensim. Several scenarios were run to determine the effects of various policy options and loosening of restrictions during and after the vaccine roll-out period. Results: When restrictions policy include moderate closure of businesses, restricting travel to Atlantic Canada, and the mandating of masks and physical distancing, the number of cumulative infections after 110 days was less than 120. However, if national travel was opened by July 5 2021 and there were no restrictions by September 2021, the number of active infections will peak at 6,114 by February 16 2022, and there will be a peak of 104 hospitalizations on February 16 2022. Immediate opening of travel and all restrictions on March 15, 2021 will result in 71,731 active infections by June 4 2021. Discussion: Moderate restrictions will be required even after the population is fully vaccinated in order to avoid a large number of infections and hospitalizations because herd immunity is not reached due to children under 12 not being vaccinated, the efficacy of the vaccine, and the portion of the population that will choose not to be vaccinated.

scholarly journals Solving Homelessness from a Complex Systems Perspective: Insights for Prevention Responses

2019 ◽  
Vol 40 (1) ◽  
pp. 465-486 ◽  
Author(s):  
Patrick J. Fowler ◽  
Peter S. Hovmand ◽  
Katherine E. Marcal ◽  
Sanmay Das
Keyword(s):  
Service Delivery ◽  
Complex Systems ◽  
Systems Approach ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Housing Assistance ◽  
Systems Perspective ◽  
Policy Interventions ◽  
Leverage Point ◽  
Developed World

Homelessness represents an enduring public health threat facing communities across the developed world. Children, families, and marginalized adults face life course implications of housing insecurity, while communities struggle to address the extensive array of needs within heterogeneous homeless populations. Trends in homelessness remain stubbornly high despite policy initiatives to end homelessness. A complex systems perspective provides insights into the dynamics underlying coordinated responses to homelessness. A constant demand for housing assistance strains service delivery, while prevention efforts remain inconsistently implemented in most countries. Feedback processes challenge efficient service delivery. A system dynamics model tests assumptions of policy interventions for ending homelessness. Simulations suggest that prevention provides a leverage point within the system; small efficiencies in keeping people housed yield disproportionately large reductions in homelessness. A need exists for policies that ensure reliable delivery of coordinated prevention efforts. A complex systems approach identifies capacities and constraints for sustainably solving homelessness.

scholarly journals A user-friendly earth system model of low complexity: the ESCIMO system dynamics model of global warming towards 2100

2016 ◽  
Vol 7 (4) ◽  
pp. 831-850 ◽  
Author(s):  
Jorgen Randers ◽  
Ulrich Golüke ◽  
Fred Wenstøp ◽  
Søren Wenstøp
Keyword(s):  
Global Warming ◽  
System Dynamics ◽  
Climate Models ◽  
Editorial Note ◽  
Earth System ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Climate History ◽  
Policy Interventions ◽  
Software Model

Abstract. We have made a simple system dynamics model, ESCIMO (Earth System Climate Interpretable Model), which runs on a desktop computer in seconds and is able to reproduce the main output from more complex climate models. ESCIMO represents the main causal mechanisms at work in the Earth system and is able to reproduce the broad outline of climate history from 1850 to 2015. We have run many simulations with ESCIMO to 2100 and beyond. In this paper we present the effects of introducing in 2015 six possible global policy interventions that cost around USD 1000 billion per year – around 1 % of world GDP. We tentatively conclude (a) that these policy interventions can at most reduce the global mean surface temperature – GMST – by up to 0.5 °C in 2050 and up to 1.0 °C in 2100 relative to no intervention. The exception is injection of aerosols into the stratosphere, which can reduce the GMST by more than 1.0 °C in a decade but creates other serious problems. We also conclude (b) that relatively cheap human intervention can keep global warming in this century below +2 °C relative to preindustrial times. Finally, we conclude (c) that run-away warming is unlikely to occur in this century but is likely to occur in the longer run. The ensuing warming is slow, however. In ESCIMO, it takes several hundred years to lift the GMST to +3 °C above preindustrial times through gradual self-reinforcing melting of the permafrost. We call for research to test whether more complex climate models support our tentative conclusions from ESCIMO. Editorial note: Please note that the acronym for the software model described in the ESD paper is now recognized to be culturally insensitive and inappropriate. The editors of the journal ESD, the journal owner European Geosciences Union, and the publisher Copernicus Publications foster equality, diversity, and inclusiveness in scientific exchange, and do not condone in any way racism, discrimination, or cultural appropriation. The authors did not intend to insult any ethnic groups by using the acronym for this software model.

scholarly journals A User-friendly Earth System Model of Low Complexity: The ESCIMO system dynamics model of global warming towards 2100

2016 ◽  
Author(s):  
Jorgen Randers ◽  
Ulrich Golüke ◽  
Fred Wenstøp ◽  
Søren Wenstøp
Keyword(s):  
Global Warming ◽  
System Dynamics ◽  
Climate Models ◽  
Low Complexity ◽  
Earth System ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Desktop Computer ◽  
Climate History ◽  
Policy Interventions

Abstract. Abstract. We have made a simple system dynamics model, ESCIMO, which runs on a desktop computer in seconds and is able to reproduce the main output from more complex climate models. ESCIMO represents the main causal mechanisms at work in the Earth system and is able to reproduce the broad outline of climate history from 1850 to 2015. We have made many simulations with ESCIMO to 2100 and beyond. In this paper we present the effects of introducing in 2015 six possible global policy interventions that cost around 1,000 billion US$ per year – around 1 % of world GDP. We tentatively conclude (a) that these policy interventions can at most reduce the global mean surface temperature – GMST – by up to 0.5 °C in 2050 and up to 1.0 °C in 2100 relative to no intervention. The exception is injection of aerosols in the stratosphere, which can reduce the GMST by more than 1.0 °C in a decade, but creates other serious problems. We also conclude (b) that relatively cheap human intervention can keep global warming in this century below +2 °C relative to preindustrial times. Finally, we conclude (c) that run-away warming is unlikely to occur in this century, but is likely to occur in the longer run. The ensuing warming is slow, however. In ESCIMO, it takes several hundred years to lift the GMST to +3 °C over preindustrial times through gradual self-reinforcing melting of the permafrost. We call for research to test whether more complex climate models support our tentative conclusions from ESCIMO.

scholarly journals How many lives can be saved? A global view on the impact of testing, herd immunity and demographics on COVID-19 fatality rates

2020 ◽  
Author(s):  
Miguel Sanchez-Romero ◽  
Vanessa di Lego ◽  
Alexia Prskawetz ◽  
Bernardo L Queiroz
Keyword(s):  
Herd Immunity ◽  
Age Distribution ◽  
Case Fatality ◽  
Population Characteristics ◽  
Seir Model ◽  
Testing Strategies ◽  
The Impact ◽  
Testing Policies ◽  
Different Levels

In this work, we assess the global impact of COVID-19 showing how demographic factors, testing policies and herd immunity are key for saving lives. We extend a standard epidemiological SEIR model in order to: (a) identify the role of demographics (population size and population age distribution) on COVID-19 fatality rates; (b) quantify the maximum number of lives that can be saved according to different testing strategies, different levels of herd immunity, and specific population characteristics; and (d) infer from the observed case fatality rates (CFR) what the true fatality rate might be. Different from previous SEIR model extensions, we implement a Bayesian Melding method in our calibration strategy which enables us to account for data limitation on the total number of deaths. We derive a distribution of the set of parameters that best replicate the observed evolution of deaths by using information from both the model and the data.

A System Dynamics Model of Health Insurance Financing in Austria

2010 ◽  
Vol 20 (2) ◽  
pp. 59-62
Author(s):  
Patrick Einzinger ◽  
Günther Zauner ◽  
G. Ganjeizadeh-Rouhani
Keyword(s):  
Health Insurance ◽  
System Dynamics ◽  
System Dynamics Model ◽  
Dynamics Model
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