scholarly journals Analyzing the Influence of Landscape Aggregation on Disease Spread to Improve Management Strategies

2019 ◽  
Vol 109 (7) ◽  
pp. 1198-1207 ◽  
Author(s):  
Coralie Picard ◽  
Samuel Soubeyrand ◽  
Emmanuel Jacquot ◽  
Gaël Thébaud
Keyword(s):  
Large Scale ◽  
Management Strategies ◽  
Disease Spread ◽  
Sensitivity Analyses ◽  
Epidemiological Models ◽  
Landscape Characteristics ◽  
Epidemic Dynamics ◽  
Economic Output ◽  
The Impact ◽  
Practical Implications

Epidemiological models are increasingly used to predict epidemics and improve management strategies. However, they rarely consider landscape characteristics although such characteristics can influence the epidemic dynamics and, thus, the effectiveness of disease management strategies. Here, we present a generic in silico approach which assesses the influence of landscape aggregation on the costs associated with an epidemic and on improved management strategies. We apply this approach to sharka, one of the most damaging diseases of Prunus trees, for which a management strategy is already applied in France. Epidemic simulations were carried out with a spatiotemporal stochastic model under various management strategies in landscapes differing in patch aggregation. Using sensitivity analyses, we highlight the impact of management parameters on the economic output of the model. We also show that the sensitivity analysis can be exploited to identify several strategies that are, according to the model, more profitable than the current French strategy. Some of these strategies are specific to a given aggregation level, which shows that management strategies should generally be tailored to each specific landscape. However, we also identified a strategy that is efficient for all levels of landscape aggregation. This one-size-fits-all strategy has important practical implications because of its simple applicability at a large scale.

scholarly journals Public policy and economic dynamics of COVID-19 spread: A mathematical modeling study

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244174
Author(s):  
Uri Goldsztejn ◽  
David Schwartzman ◽  
Arye Nehorai
Keyword(s):  
Mathematical Modeling ◽  
Large Scale ◽  
Population Based ◽  
Disease Spread ◽  
Economic Damage ◽  
Baseline Scenario ◽  
Economic Output ◽  
Economic Vulnerability ◽  
Restrictive Measures ◽  
The Impact

With the COVID-19 pandemic infecting millions of people, large-scale isolation policies have been enacted across the globe. To assess the impact of isolation measures on deaths, hospitalizations, and economic output, we create a mathematical model to simulate the spread of COVID-19, incorporating effects of restrictive measures and segmenting the population based on health risk and economic vulnerability. Policymakers make isolation policy decisions based on current levels of disease spread and economic damage. For 76 weeks in a population of 330 million, we simulate a baseline scenario leaving strong isolation restrictions in place, rapidly reducing isolation restrictions for non-seniors shortly after outbreak containment, and gradually relaxing isolation restrictions for non-seniors. We use 76 weeks as an approximation of the time at which a vaccine will be available. In the baseline scenario, there are 235,724 deaths and the economy shrinks by 34.0%. With a rapid relaxation, a second outbreak takes place, with 525,558 deaths, and the economy shrinks by 32.3%. With a gradual relaxation, there are 262,917 deaths, and the economy shrinks by 29.8%. We also show that hospitalizations, deaths, and economic output are quite sensitive to disease spread by asymptomatic people. Strict restrictions on seniors with very gradual lifting of isolation for non-seniors results in a limited number of deaths and lesser economic damage. Therefore, we recommend this strategy and measures that reduce non-isolated disease spread to control the pandemic while making isolation economically viable.

scholarly journals Public policy and economic dynamics of COVID-19 spread: a mathematical modeling study

2020 ◽  
Author(s):  
Uri Goldsztejn ◽  
David Schwartzman ◽  
Arye Nehorai
Keyword(s):  
Large Scale ◽  
Population Based ◽  
Disease Spread ◽  
Economic Damage ◽  
Baseline Scenario ◽  
Seir Model ◽  
Economic Output ◽  
Economic Vulnerability ◽  
Restrictive Measures ◽  
The Impact

AbstractWith the COVID-19 pandemic infecting millions of people, large-scale quarantine policies have been enacted across the globe. To assess the impact of quarantine measures on deaths, hospitalizations, and economic output, we expand the classical SEIR model to simulate the spread of COVID-19, incorporating effects of restrictive measures and segmenting the population based on health risk and economic vulnerability. For 76 weeks in a population of 330 million, we simulate a baseline scenario leaving current quarantine restrictions in place, rapidly reducing quarantine restrictions for non-seniors shortly after outbreak containment, and gradually relaxing quarantine restrictions for non-seniors. In the baseline scenario, there are 207,906 deaths and the economy shrinks by 34.0%. With a rapid relaxation, a second outbreak takes place, with 788,815 deaths, and the economy shrinks by 28.2%. With a gradual relaxation, there are 221,743 deaths, and the economy shrinks by 29.4%. Additionally, hospitalizations, deaths, and economic output are quite sensitive to disease spread by asymptomatic people. Strict restrictions on seniors with very gradual lifting of quarantine for non-seniors results in a limited number of deaths and lesser economic damage. Therefore, we recommend this strategy and measures that reduce non-quarantined disease spread to control the pandemic while making quarantine economically viable.

Does the second wave of COVID-19 undermine corporate immunity? International evidence

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Huy Viet Hoang ◽  
Cuong Nguyen ◽  
Khanh Hoang
Keyword(s):  
Stock Returns ◽  
Stock Price ◽  
Fixed Effects ◽  
Management Strategies ◽  
The United States ◽  
Least Square ◽  
Content Type ◽  
The Impact ◽  
Second Wave ◽  
Practical Implications

PurposeThis study compares the impact of the COVID-19 pandemic on stock returns in the first two waves of infection across selected markets, given built-in corporate immunity before the global outbreak.Design/methodology/approachThe data are collected from listed firms in five markets that have experienced the second wave of COVID-19 contagion, namely the United States (US), Australia, China, Hong Kong and South Korea. The period of investigation in this study ranges from January 24 to August 28, 2020 to cover the first two COVID-19 waves in selected markets. The study estimates the research model by employing the ordinary least square method with fixed effects to control for the heterogeneity that may confound the empirical outcomes.FindingsThe analysis reveals that firms with larger size and more cash reserves before the COVID-19 outbreak have better stock performance under the first wave; however, these advantages impede stock resilience during the second wave. Corporate governance practices significantly influence stock returns only in the first wave as their effects fade when the second wave emerges. The results also suggest that in economies with greater power distance, although stock price depreciation was milder in the first wave, it is more intense when new cases again surge after the first wave was contained.Practical implicationsThis paper provides practical implications for corporate managers, policymakers and governments concerning crisis management strategies for COVID-19 and future pandemics.Originality/valueThis study is the first to evaluate built-in corporate immunity before the COVID-19 shock under successive contagious waves. Besides, this study accentuates the importance of cultural understanding in weathering the ongoing pandemic across different markets.

scholarly journals Development of PM<sub>2.5</sub> source impact spatial fields using a hybrid source apportionment air quality model

2015 ◽  
Vol 8 (7) ◽  
pp. 2153-2165 ◽  
Author(s):  
C. E. Ivey ◽  
H. A. Holmes ◽  
Y. T. Hu ◽  
J. A. Mulholland ◽  
A. G. Russell
Keyword(s):  
Air Quality ◽  
Source Apportionment ◽  
Large Scale ◽  
Major Ions ◽  
Current Knowledge ◽  
Direct Method ◽  
Hybrid Approach ◽  
Sensitivity Analyses ◽  
Adjustment Factors ◽  
The Impact

Abstract. An integral part of air quality management is knowledge of the impact of pollutant sources on ambient concentrations of particulate matter (PM). There is also a growing desire to directly use source impact estimates in health studies; however, source impacts cannot be directly measured. Several limitations are inherent in most source apportionment methods motivating the development of a novel hybrid approach that is used to estimate source impacts by combining the capabilities of receptor models (RMs) and chemical transport models (CTMs). The hybrid CTM–RM method calculates adjustment factors to refine the CTM-estimated impact of sources at monitoring sites using pollutant species observations and the results of CTM sensitivity analyses, though it does not directly generate spatial source impact fields. The CTM used here is the Community Multiscale Air Quality (CMAQ) model, and the RM approach is based on the chemical mass balance (CMB) model. This work presents a method that utilizes kriging to spatially interpolate source-specific impact adjustment factors to generate revised CTM source impact fields from the CTM–RM method results, and is applied for January 2004 over the continental United States. The kriging step is evaluated using data withholding and by comparing results to data from alternative networks. Data withholding also provides an estimate of method uncertainty. Directly applied (hybrid, HYB) and spatially interpolated (spatial hybrid, SH) hybrid adjustment factors at withheld observation sites had a correlation coefficient of 0.89, a linear regression slope of 0.83 ± 0.02, and an intercept of 0.14 ± 0.02. Refined source contributions reflect current knowledge of PM emissions (e.g., significant differences in biomass burning impact fields). Concentrations of 19 species and total PM2.5 mass were reconstructed for withheld observation sites using HYB and SH adjustment factors. The mean concentrations of total PM2.5 at withheld observation sites were 11.7 (± 8.3), 16.3 (± 11), 8.59 (± 4.7), and 9.2 (± 5.7) μg m−3 for the observations, CTM, HYB, and SH predictions, respectively. Correlations improved for concentrations of major ions, including nitrate (CMAQ–DDM (decoupled direct method): 0.404, SH: 0.449), ammonium (CMAQ–DDM: 0.454, SH: 0.492), and sulfate (CMAQ–DDM: 0.706, SH: 0.730). Errors in simulated concentrations of metals were reduced considerably: 295 % (CMAQ–DDM) to 139 % (SH) for vanadium; and 1340 % (CMAQ–DDM) to 326 % (SH) for manganese. Errors in simulated concentrations of some metals are expected to remain given the uncertainties in source profiles. Species concentrations were reconstructed using SH results, and the error relative to observed concentrations was greatly reduced as compared to CTM-simulated concentrations. Results demonstrate that the hybrid method along with a spatial extension can be used for large-scale, spatially resolved source apportionment studies where observational data are spatially and temporally limited.

scholarly journals Process Management: the Case of the Foreign and Commonwealth Office

2020 ◽  
Vol 12 (1) ◽  
pp. 58-77
Author(s):  
Marta Mazur-Małek
Keyword(s):  
Process Management ◽  
Management Strategies ◽  
Value Added ◽  
Process Efficiency ◽  
Review Of Literature ◽  
The Cost ◽  
The Impact ◽  
Practical Implications ◽  
Practical Nature ◽  
Modern Technologies

AbstractObjective: The objective of the article is to mark the introduction of process changes in relation to the Emergency Travel Document service by The Foreign & Commonwealth Office. The paper analyses the changes and relates them to process and cost management strategies. Thus, it presents how process efficiency may be managedMethodology: The article is of a theoretical and practical nature. The method used in the theoretical part is a review of literature on process management. The second part includes an analysis of The Foreign & Commonwealth Office’s own documents.Findings: The use of digitalization greatly facilitates the process for British citizens who are abroad and need to obtain a travel document. This facilitation applies to both customers and FCO employees. Numerous factors influence the processing time reduction, which in turn increases productivity.Value Added: This article presents an example of the practical use of digitization in the process of issuing the Emergency Travel Document. The value is to show the impact of modern technologies on improving the processes for the organization itself (in the form of optimizing operational costs and increasing efficiency) and for the customers.Recommendations: The use of digitization can be successfully implemented to streamline organizational processes. It can help in reducing their time and limiting human involvement. Increased productivity lowers the cost of a single unit of the service. The changes allow for a more standardized and repeatable service. The approach can be used to manage processes in any organization; though practical implications outlined in the text can serve as an example for other organizations offering similar services.

Investigation of spatial configuration management on social distancing of recreational clubhouse for COVID-19 in Penang, Malaysia

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nur Adibah Binti Abdul Nasir ◽  
Ahmad Sanusi Hassan ◽  
Fatemeh Khozaei ◽  
Muhammad Hafeez Bin Abdul Nasir
Keyword(s):  
Spatial Organization ◽  
Spatial Configuration ◽  
Management Strategies ◽  
Spatial Arrangement ◽  
Public Spaces ◽  
Disease Spread ◽  
Content Type ◽  
Factors Affecting ◽  
Social Distancing ◽  
The Impact

PurposeSince the appearance of COVID-19 social distancing and staying home have been recommended repeatedly by the governments for disease prevention. As the challenge continues to remain the current study seeks to examine the factors affecting social distancing through space planning and management. More specifically the current study aims to examine the appropriateness of the spatial organization and space configuration of a clubhouse with a linear plan layout in the mitigation of the spread of infections due to serious pandemic COVID-19.Design/methodology/approachFor an enhanced understanding of the impact of spatial arrangements of public spaces plan on the effective implementation of social distancing this study has used the space syntax analysis method. The MPSP clubhouse building in Penang, Malaysia was selected as the case study. The level of permeability and wayfinding were determined in the building plan and were illustrated using photoshop software to depict the interrelation between the indoor spaces and building circulation. Graphs of the depth of space were used to analyze the level of permeability and wayfinding to illustrate the possibility of social distancing in the plan.FindingsThe result of the study shows the significant role of proper plan layout design on social distancing. While clear and direct wayfinding can positively be associated with more effective social distancing, the inefficient design of user access, inappropriate locations of multiple entry and exit and indefinite directions of users' inside buildings can impose slight limitations. The average level of permeability might suggest ineffective spatial arrangement, ignoring the needs of spatial segregation. The study further found that the linear plan layouts with proper zoning and effective management strategies can be considered a proper layout to facilitate social distancing and the spread of COVID-19.Originality/valueThe current study is unique in terms of examination of the spatial configuration of linear public spaces plan layout for possible temporary adaptability to curb disease spread during the unexpected advent of a pandemic. Based on researchers' best of knowledge it is the first time that the impact of recreational space design on social distancing has been examined. The study also originally sheds light on the fact that the commonly used guideline for the social distancing of 1–2 m between 2 persons, in reality, is practically inadequate given the nature of the sports activities.

Assessing the effects of climate change on US West Coast sablefish productivity and on the performance of alternative management strategies

2019 ◽  
Vol 76 (6) ◽  
pp. 1524-1542
Author(s):  
Melissa A Haltuch ◽  
Z Teresa A’mar ◽  
Nicholas A Bond ◽  
Juan L Valero
Keyword(s):  
Climate Change ◽  
West Coast ◽  
Large Scale ◽  
Climate Models ◽  
Global Climate ◽  
Management Strategies ◽  
Climate Impacts ◽  
Global Climate Models ◽  
The Impact ◽  
Us West

Abstract US West Coast sablefish are economically valuable, with landings of 11.8 million pounds valued at over $31 million during 2016, making assessing and understanding the impact of climate change on the California Current (CC) stock a priority for (1) forecasting future stock productivity, and (2) testing the robustness of management strategies to climate impacts. Sablefish recruitment is related to large-scale climate forcing indexed by regionally correlated sea level (SL) and zooplankton communities that pelagic young-of-the-year sablefish feed upon. This study forecasts trends in future sablefish productivity using SL from Global Climate Models (GCMs) and explores the robustness of harvest control rules (HCRs) to climate driven changes in recruitment using management strategy evaluation (MSE). Future sablefish recruitment is likely to be similar to historical recruitment but may be less variable. Most GCMs suggest that decadal SL trends result in recruitments persisting at lower levels through about 2040 followed by higher levels that are more favorable for sablefish recruitment through 2060. Although this MSE suggests that spawning biomass and catches will decline, and then stabilize, into the future under both HCRs, the sablefish stock does not fall below the stock size that leads to fishery closures.

scholarly journals Improving Management Strategies of Plant Diseases Using Sequential Sensitivity Analyses

2019 ◽  
Vol 109 (7) ◽  
pp. 1184-1197 ◽  
Author(s):  
Loup Rimbaud ◽  
Sylvie Dallot ◽  
Claude Bruchou ◽  
Sophie Thoyer ◽  
Emmanuel Jacquot ◽  
...  
Keyword(s):  
Net Present Value ◽  
Management Strategies ◽  
Optimal Solution ◽  
Plant Diseases ◽  
Control Measures ◽  
Disease Suppression ◽  
Simultaneous Optimization ◽  
Disease Spread ◽  
Sensitivity Analyses ◽  
Plum Pox Virus

Improvement of management strategies of epidemics is often hampered by constraints on experiments at large spatiotemporal scales. A promising approach consists of modeling the biological epidemic process and human interventions, which both impact disease spread. However, few methods enable the simultaneous optimization of the numerous parameters of sophisticated control strategies. To do so, we propose a heuristic approach (i.e., a practical improvement method approximating an optimal solution) based on sequential sensitivity analyses. In addition, we use an economic improvement criterion based on the net present value, accounting for both the cost of the different control measures and the benefit generated by disease suppression. This work is motivated by sharka (caused by Plum pox virus), a vector-borne disease of prunus trees (especially apricot, peach, and plum), the management of which in orchards is mainly based on surveillance and tree removal. We identified the key parameters of a spatiotemporal model simulating sharka spread and control and approximated optimal values for these parameters. The results indicate that the current French management of sharka efficiently controls the disease, but it can be economically improved using alternative strategies that are identified and discussed. The general approach should help policy makers to design sustainable and cost-effective strategies for disease management.

scholarly journals Modelling the impact of poaching on metapopulation viability for data-limited species

2017 ◽  
Vol 74 (6) ◽  
pp. 894-906 ◽  
Author(s):  
Abbey E. Camaclang ◽  
Janelle M.R. Curtis ◽  
Ilona Naujokaitis-Lewis ◽  
Mark S. Poesch ◽  
Marten A. Koops
Keyword(s):  
Management Strategies ◽  
Simulation Models ◽  
Sensitivity Analyses ◽  
Future Research ◽  
Spatially Explicit ◽  
Barkley Sound ◽  
Spatially Explicit Population Model ◽  
Future Research Directions ◽  
Explicit Simulation ◽  
The Impact

We developed a spatially explicit simulation model of poaching behaviour to quantify the relative influence of the intensity, frequency, and spatial distribution of poaching on metapopulation viability. We integrated our model of poaching with a stochastic, habitat-based, spatially explicit population model, applied it to examine the impact of poaching on northern abalone (Haliotis kamtschatkana) metapopulation dynamics in Barkley Sound, British Columbia, Canada, and quantified model sensitivity to input parameters. While demographic parameters remained important in predicting extinction probabilities for northern abalone, our simulations indicate that the odds of extinction are twice as high when populations are subjected to poaching. Viability was influenced by poaching variables that affect the total number of individuals removed. Of these, poaching mortality was the most influential in predicting metapopulation viability, with each 0.1 increase in mortality rate resulting in 22.6% increase in the odds of extinction. By contrast, the location and spatial correlation of events were less important predictors of viability. When data are limited, simulation models of poaching combined with sensitivity analyses can be useful in informing management strategies and future research directions.

scholarly journals The effect of control measures on COVID-19 transmission in Italy: Comparison with Guangdong province in China

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Pei-Yu Liu ◽  
Sha He ◽  
Li-Bin Rong ◽  
San-Yi Tang
Keyword(s):  
Media Coverage ◽  
Early Stage ◽  
Guangdong Province ◽  
Individual Behavior ◽  
Control Measures ◽  
Disease Spread ◽  
Sensitivity Analyses ◽  
And Control ◽  
Parameter Values ◽  
The Impact

Abstract Background COVID-19 has spread all around the world. Italy is one of the worst affected countries in Europe. Although there is a trend of relief, the epidemic situation hasn’t stabilized yet. This study aims to investigate the dynamics of the disease spread in Italy and provide some suggestions on containing the epidemic. Methods We compared Italy’s status at the outbreak stage and control measures with Guangdong Province in China by data observation and analysis. A modified autonomous SEIR model was used to study the COVID-19 epidemic and transmission potential during the early stage of the outbreak in Italy. We also utilized a time-dependent dynamic model to study the future disease dynamics in Italy. The impact of various non-pharmaceutical control measures on epidemic was investigated through uncertainty and sensitivity analyses. Results The comparison of specific measures implemented in the two places and the time when the measures were initiated shows that the initial prevention and control actions in Italy were not sufficiently timely and effective. We estimated parameter values based on available cumulative data and calculated the basic reproduction number to be 4.32 before the national lockdown in Italy. Based on the estimated parameter values, we performed numerical simulations to predict the epidemic trend and evaluate the impact of contact limitation, detection and diagnosis, and individual behavior change due to media coverage on the epidemic. Conclusions Italy was in a severe epidemic status and the control measures were not sufficiently timely and effective in the beginning. Non-pharmaceutical interventions, including contact restrictions and improvement of case recognition, play an important role in containing the COVID-19 epidemic. The effect of individual behavior changes due to media update of the outbreak cannot be ignored. For policy-makers, early and strict blockade measures, fast detection and improving media publicity are key to containing the epidemic.

Sign in / Sign up

Export Citation Format

Share Document