scholarly journals Infectious disease dynamics and restrictions on social gathering size

2022 ◽  
Author(s):  
Christopher B Boyer ◽  
Eva Rumpler ◽  
Stephen M Kissler ◽  
Marc Lipsitch
Keyword(s):  
Scientific Basis ◽  
Disease Dynamics ◽  
Policy Makers ◽  
Transmission Parameters ◽  
Empirical Estimates ◽  
Contact Patterns ◽  
Heavy Tailed ◽  
Using Data ◽  
Parameter Ranges ◽  
Size Threshold

Social gatherings can be an important locus of transmission for many pathogens including SARS-CoV-2. During an outbreak, restricting the size of these gatherings is one of several non-pharmaceutical interventions available to policy-makers to reduce transmission. Often these restrictions take the form of prohibitions on gatherings above a certain size. While it is generally agreed that such restrictions reduce contacts, the specific size threshold separating "allowed" from "prohibited" gatherings often does not have a clear scientific basis, which leads to dramatic differences in guidance across location and time. Building on the observation that gathering size distributions are often heavy-tailed, we develop a theoretical model of transmission during gatherings and their contribution to general disease dynamics. We find that a key, but often overlooked, determinant of the optimal threshold is the distribution of gathering sizes. Using data on pre-pandemic contact patterns from several sources as well as empirical estimates of transmission parameters for SARS-CoV-2, we apply our model to better understand relationship between restriction threshold and reduction in cases. We find that, under reasonable transmission parameter ranges, restrictions may have to be set quite low to have any demonstrable effect on cases due to relative frequency of smaller gatherings. We compare our conceptual model with observed changes in reported contacts during lockdown in March of 2020.

scholarly journals Simulation of leaf curl disease dynamics in chili for strategic management options

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Buddhadeb Roy ◽  
Shailja Dubey ◽  
Amalendu Ghosh ◽  
Shalu Misra Shukla ◽  
Bikash Mandal ◽  
...  
Keyword(s):  
Disease Risk ◽  
Virus Transmission ◽  
Host Population ◽  
High Rate ◽  
Disease Dynamics ◽  
Model Framework ◽  
Management Options ◽  
Transmission Parameters ◽  
Vector Population ◽  
Leaf Curl

AbstractLeaf curl, a whitefly-borne begomovirus disease, is the cause of frequent epidemic in chili. In the present study, transmission parameters involved in tripartite interaction are estimated to simulate disease dynamics in a population dynamics model framework. Epidemic is characterized by a rapid conversion rate of healthy host population into infectious type. Infection rate as basic reproduction number, R0 = 13.54, has indicated a high rate of virus transmission. Equilibrium population of infectious host and viruliferous vector are observed to be sensitive to the immigration parameter. A small increase in immigration rate of viruliferous vector increased the population of both infectious host and viruliferous vector. Migrant viruliferous vectors, acquisition, and transmission rates as major parameters in the model indicate leaf curl epidemic is predominantly a vector -mediated process. Based on underlying principles of temperature influence on vector population abundance and transmission parameters, spatio-temporal pattern of disease risk predicted is noted to correspond with leaf curl distribution pattern in India. Temperature in the range of 15–35 °C plays an important role in epidemic as both vector population and virus transmission are influenced by temperature. Assessment of leaf curl dynamics would be a useful guide to crop planning and evolution of efficient management strategies.

scholarly journals Small firms and the COVID-19 insolvency gap

2021 ◽  
Author(s):  
Julian Oliver Dörr ◽  
Georg Licht ◽  
Simona Murmann
Keyword(s):  
Financial Distress ◽  
Small Firms ◽  
English Summary ◽  
Policy Support ◽  
Policy Response ◽  
Special Role ◽  
Current Crisis ◽  
Policy Makers ◽  
Large Wave ◽  
Using Data

AbstractCOVID-19 placed a special role on fiscal policy in rescuing companies short of liquidity from insolvency. In the first months of the crisis, SMEs as the backbone of Germany’s economy benefited from large and mainly indiscriminate aid measures. Avoiding business failures in a whatever-it-takes fashion contrasts, however, with the cleansing mechanism of economic crises: a mechanism which forces unviable firms out of the market, thereby reallocating resources efficiently. By focusing on firms’ pre-crisis financial standing, we estimate the extent to which the policy response induced an insolvency gap and analyze whether the gap is characterized by firms which were already struggling before the pandemic. With the policy measures being focused on smaller firms, we also examine whether this insolvency gap differs with respect to firm size. Our results show that the COVID-19 policy response in Germany has triggered a backlog of insolvencies that is particularly pronounced among financially weak, small firms, having potential long-term implications on entrepreneurship and economic recovery.Plain English Summary This study analyzes the extent to which the strong policy support to companies in the early phase of the COVID-19 crisis has prevented a large wave of corporate insolvencies. Using data of about 1.5 million German companies, it is shown that it was mainly smaller firms that experienced strong financial distress and would have gone bankrupt without policy assistance. In times of crises, insolvencies usually allow for a reallocation of employees and capital to more efficient firms. However, the analysis reveals that this ‘cleansing effect’ is hampered in the current crisis as the largely indiscriminate granting of liquidity subsidies and the temporary suspension of the duty to file for insolvency have caused an insolvency gap that is driven by firms which were already in a weak financial position before the crisis. Overall, the insolvency gap is estimated to affect around 25,000 companies, a substantial number compared to the around 16,300 actual insolvencies in 2020. In the ongoing crisis, policy makers should prefer instruments favoring entrepreneurs who respond innovatively to the pandemic instead of prolonging the survival of near-insolvent firms.

Estimating Floor Area Ratio of Urban Buildings Based on the QuickBird Image

2012 ◽  
Vol 450-451 ◽  
pp. 614-617
Author(s):  
Yi Zhou Wu ◽  
Bo Li
Keyword(s):  
Scientific Basis ◽  
Area Ratio ◽  
Administrative District ◽  
Policy Makers ◽  
Floor Area ◽  
Floor Area Ratio ◽  
Urban Economic Development ◽  
Urban Buildings ◽  
Object Based ◽  
Pca Transform

Floor area ratio (FAR) is fundamentally important for urban economic development and for urban design, planning and management. This paper tried to enhance the texture information of the QuickBird image by using HIS and PCA transform methods in Yiwu city as a case study. An object-based method was proposed to process the enhanced QuickBird image for the shadow of buildings and building object areas, and the building heights were accurately calculated based on the shadow of buildings. The building object areas and heights were integrated with an administrative district map in Yiwu city to estimate FAR. Tests with this above method demonstrated excellent accuracy in terms of FAR estimation. The high spatial resolution images have great potential in quickly and accurately estimating FAR, providing a scientific basis to policy makers and urban planners.

scholarly journals Adoption of Natural Gas Vehicles – Estimates for the U.S. and the State of Texas

2016 ◽  
Author(s):  
Chen (Sarah) Xu ◽  
Liang-Chieh (Victor) Cheng
Keyword(s):  
Natural Gas ◽  
Financial Incentives ◽  
Fossil Fuel ◽  
Diffusion Models ◽  
The State ◽  
Policy Makers ◽  
Fuel Taxes ◽  
Natural Gas Vehicles ◽  
Using Data ◽  
The U.S

Natural gas vehicles (NGV) have attracted more and more attention from policy makers since natural gas is a clean substitute for traditional fossil fuel that is also readily accessible. In some areas such as the state of Texas, vehicles that do not use traditional fossil fuel (e.g., NGVs) are exempt from paying fuel taxes. Government financial incentives have motivated substantial adoption of NGVs. This paper studies NGV adoption behavior in both U.S. and Texas markets to estimate the dynamics of NGV diffusion. This research employs well-known Bass diffusion models applied to NGV adoption, using data from both the U.S. and Texas. Among several interesting results, we find that NGV adoption through an imitation effect appears to be significant for the U.S. NGV market.

Knowledge Co production and Behavioural Change, Collaborative approaches for promoting low carbon mobility

2016 ◽  
Author(s):  
Stewart Barr ◽  
Gareth Shaw
Keyword(s):  
Climate Change ◽  
Behavioural Change ◽  
Academic Research ◽  
Low Carbon ◽  
Policy Makers ◽  
Productive Process ◽  
Emergent Literature ◽  
Using Data ◽  
The Uk ◽  
Personal Travel

Behavioural change has become regarded as a key tool for policy makers to promote behavioural change that can reduce carbon emissions from personal travel. Yet academic research has suggested that promoting low carbon travel behaviours, in particular those associated with leisure and tourism practices, is particularly challenging because of the highly valued and conspicuous nature of the consumption involved. Accordingly, traditional top-down approaches to developing behavioural change campaigns have largely been ineffectual in this field and this chapter explores innovative ways to understand and develop behavioural change campaigns that are driven from the bottom upwards. In doing so, we draw on emergent literature from management studies and social marketing to explore how ideas of service dominant logic can be used to engage consumers in developing each stage of a behavioural change campaign. Using data and insights from research conducted in the south-east of the UK, we outline and evaluate the process for co-producing knowledge about low carbon travel and climate change. We illustrate how behavioural change campaign creation can be an engaging, lively and productive process of knowledge and experience sharing. The chapter ends by considering the role that co-production and co-creation can have in developing strategies for low carbon mobility and, more broadly, the ways in which publics understand and react to anthropogenic climate change.

scholarly journals Do Political Connections Affect the Conservative Financial Reporting of Family Firms?

2019 ◽  
Vol 11 (20) ◽  
pp. 5563
Author(s):  
Hsin-Yi Chi ◽  
Tzu-Ching Weng ◽  
Guang-Zheng Chen ◽  
Shu-Ping Chen
Keyword(s):  
Financial Reporting ◽  
Family Firms ◽  
Political Connections ◽  
Policy Makers ◽  
Listed Firms ◽  
Reporting Incentives ◽  
Final Sample ◽  
The Family ◽  
Governance Practice ◽  
Using Data

This paper investigates the effect of political connections on the association between family firms and conservative financial reporting. While family firms have incentives to reduce agency and litigation-related costs by means of conservative reporting, firms with political connections tend to have opaque financial reporting, which enable them to engage in rent-seeking activities. Using data for Taiwanese listed firms between 1996 and 2012, the final sample observations were 13,877 firm-year observations from a population of 21,393 firm-year observations. We found that political connections weaken the positive relationship between family ownership and conservative financial reporting. This suggests that politically connected family firms make fewer demands for conservative financial reporting. This study contributes to the literature on how political connections affect the family owners’ reporting incentives. Policy makers may consider political connections as an essential factor with respect to establishing governance practice in family firms.

Recidivism Among Justice-Involved Youth: Findings From JJ-TRIALS

2020 ◽  
Vol 47 (9) ◽  
pp. 1059-1078
Author(s):  
Angela A. Robertson ◽  
Zhou Fang ◽  
Doris Weiland ◽  
George Joe ◽  
Sheena Gardner ◽  
...  
Keyword(s):  
Drug Abuse ◽  
Juvenile Justice ◽  
County Level ◽  
Multilevel Analyses ◽  
Recidivism Rates ◽  
Policy Makers ◽  
Individual Level ◽  
Research Questions ◽  
Complex Relationships ◽  
Using Data

Recidivism, and the factors related to it, remains a highly significant concern among juvenile justice researchers, practitioners, and policy makers. Recent studies highlight the need to examine multiple measures of recidivism as well as conduct multilevel analyses of this phenomenon. Using data collected in a National Institute on Drug Abuse (NIDA)-funded Juvenile Justice-Translational Research on Interventions for Adolescents in the Legal System (JJ-TRIALS) cooperative agreement, we examined individual- and site-level factors related to 1-year recidivism among probation youth in 20 sites in five states to answer research questions related to how recidivism rates differ across sites and the relationships between individual-level variables and a county-level concentrated disadvantage measure and recidivism. Our findings of large site differences in recidivism rates, and complex relationships between individual and county-level predictors of recidivism, highlight the need for more nuanced, contextually informed, multilevel approaches in studying recidivism among juveniles.

Modeling and Measuring Impacts From Ash Landfilling: Using Data to Inform Regulatory Policy

2011 ◽  
Author(s):  
Stephen G. Zemba ◽  
Michael R. Ames ◽  
Laura C. Green
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Ambient Air ◽  
Waste To Energy ◽  
Data Sets ◽  
Fugitive Emissions ◽  
Policy Makers ◽  
Regulatory Policies ◽  
Using Data ◽  
Ash Disposal

Most ash generated by waste-to-energy (WTE) facilities in the U.S. is landfilled. Studies undertaken in the late 1980’s and early 1990’s indicated no significant environmental concerns associated with ash landfilling. However, in 2001, policy-makers at the Massachusetts Department of Environmental Protection (MA DEP) became concerned that the “cumulative” impacts of landfills, including ash landfills, might pose a risk to human health. To address this concern, we performed an in-depth assessment of impacts to air quality, and theoretical risks to health, from fugitive emissions associated with an ash landfill. Nine sources of fugitive ash emissions were modeled using methods that coupled detailed information about the site operations, ash properties, and meteorological conditions on an hour-by-hour basis. The results of these assessments, combined with ambient air data collected by others, demonstrated that the impacts from fugitive emissions of the ash were no more than negligible. Accordingly, in 2006, MA DEP revised its policy, exempting ash disposal landfills from the requirement to demonstrate no significant impact, effectively granting presumptive certainty to ash landfills that employ best management practices. Detailed analyses such as described herein, combined with robust data sets, can form the basis of more efficient regulatory policies.

scholarly journals Incubation periods impact the spatial predictability of cholera and Ebola outbreaks in Sierra Leone

2020 ◽  
Vol 117 (9) ◽  
pp. 5067-5073 ◽  
Author(s):  
Rebecca Kahn ◽  
Corey M. Peak ◽  
Juan Fernández-Gracia ◽  
Alexandra Hill ◽  
Amara Jambai ◽  
...  
Keyword(s):  
Sierra Leone ◽  
Incubation Period ◽  
Population Connectivity ◽  
Disease Spread ◽  
Long Distance ◽  
Spatial Spread ◽  
Transmission Parameters ◽  
Incubation Periods ◽  
Using Data ◽  
The Impact

Forecasting the spatiotemporal spread of infectious diseases during an outbreak is an important component of epidemic response. However, it remains challenging both methodologically and with respect to data requirements, as disease spread is influenced by numerous factors, including the pathogen’s underlying transmission parameters and epidemiological dynamics, social networks and population connectivity, and environmental conditions. Here, using data from Sierra Leone, we analyze the spatiotemporal dynamics of recent cholera and Ebola outbreaks and compare and contrast the spread of these two pathogens in the same population. We develop a simulation model of the spatial spread of an epidemic in order to examine the impact of a pathogen’s incubation period on the dynamics of spread and the predictability of outbreaks. We find that differences in the incubation period alone can determine the limits of predictability for diseases with different natural history, both empirically and in our simulations. Our results show that diseases with longer incubation periods, such as Ebola, where infected individuals can travel farther before becoming infectious, result in more long-distance sparking events and less predictable disease trajectories, as compared to the more predictable wave-like spread of diseases with shorter incubation periods, such as cholera.

The Role of Sex and Age on Pre-drinking: An Exploratory International Comparison of 27 Countries

2019 ◽  
Vol 54 (4) ◽  
pp. 378-385 ◽  
Author(s):  
Jason Ferris ◽  
Cheneal Puljević ◽  
Florian Labhart ◽  
Adam Winstock ◽  
Emmanuel Kuntsche
Keyword(s):  
Multilevel Models ◽  
The United States ◽  
Drinking Behaviour ◽  
Single Model ◽  
Policy Makers ◽  
Worldwide Phenomenon ◽  
Using Data ◽  
The Impact ◽  
Multivariate Multilevel Models

Abstract Aims This exploratory study aims to model the impact of sex and age on the percentage of pre-drinking in 27 countries, presenting a single model of pre-drinking behaviour for all countries and then comparing the role of sex and age on pre-drinking behaviour between countries. Methods Using data from the Global Drug Survey, the percentages of pre-drinkers were estimated for 27 countries from 64,485 respondents. Bivariate and multivariate multilevel models were used to investigate and compare the percentage of pre-drinking by sex (male and female) and age (16–35 years) between countries. Results The estimated percentage of pre-drinkers per country ranged from 17.8% (Greece) to 85.6% (Ireland). The influence of sex and age on pre-drinking showed large variation between the 27 countries. With the exception of Canada and Denmark, higher percentages of males engaged in pre-drinking compared to females, at all ages. While we noted a decline in pre-drinking probability among respondents in all countries after 21 years of age, after the age of 30 this probability remained constant in some countries, or even increased in Brazil, Canada, England, Ireland, New Zealand and the United States. Conclusions Pre-drinking is a worldwide phenomenon, but varies substantially by sex and age between countries. These variations suggest that policy-makers would benefit from increased understanding of the particularities of pre-drinking in their own country to efficiently target harmful pre-drinking behaviours.

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