scholarly journals An evolutionary model of long term cyclical variations of catching up and falling behind

1996 ◽  
pp. 29-47
Author(s):  
Gerald Silverberg ◽  
Bart Verspagen
Keyword(s):  
Evolutionary Model ◽  
Catching Up

scholarly journals An evolutionary model of long term cyclical variations of catching up and falling behind

1995 ◽  
Vol 5 (3) ◽  
pp. 209-227 ◽  
Author(s):  
Gerald Silverberg ◽  
Bart Verspagen
Keyword(s):  
Evolutionary Model ◽  
Catching Up

scholarly journals The resurgence risk of COVID-19 in the presence of immunity waning and ADE effect: a mathematical modelling study

2021 ◽  
Author(s):  
Weike Zhou ◽  
Biao Tang ◽  
Yao Bai ◽  
Yiming Shao ◽  
Yanni Xiao ◽  
...  
Keyword(s):  
Mainland China ◽  
Population Level ◽  
Mass Vaccination ◽  
Low Risk ◽  
Vaccination Program ◽  
Post Vaccination ◽  
Catching Up ◽  
Vaccination Period ◽  
Transmission Ability

Since the end of 2020, the mass vaccination has been actively promoted and seemed to be effective to bring the COVID-19 pandemic under control. However, the fact of immunity waning and the possible existence of antibody-dependent enhancement (ADE) make the situation uncertain. We developed a dynamic model of COVID-19 incorporating vaccination and immunity waning, which was calibrated by using the data of accumulative vaccine doses administered and the COVID-19 epidemic in 2020 in mainland China. We explored how long the current vaccination program can prevent China in a low risk of resurgence, and how ADE affects the long-term trajectory of COVID-19 epidemics. The prediction suggests that the vaccination coverage with at least one dose reach 95.87%, and with two-doses reach 77.92% on August 31, 2021. However, even with the mass vaccination, randomly introducing infected cases in the post-vaccination period can result in large outbreaks quickly in the presence of immunity waning, particularly for SARS-CoV-2 variants with higher transmission ability. The results showed that with the current vaccination program and a proportion of 50% population wearing masks, mainland China can be protected in a low risk of resurgence till 2023/01/18. However, ADE effect and higher transmission ability for variants would significantly shorten the protective period for more than 1 year. Furthermore, intermittent outbreaks can occur while the peak values of the subsequential outbreaks are decreasing, meaning that subsequential outbreaks boosted the immunity in the population level, which further indicating that catching-up vaccination program can help to mitigate the possible outbreaks, even avoid the outbreaks. The findings reveal that integrated effects of multiple factors, including immunity waning, ADE, relaxed interventions, and higher transmission ability of variants, make the control of COVID-19 much more difficult. We should get ready for a long struggle with COVID-19, and should not totally rely on COVID-19 vaccine.

scholarly journals What has happened and what has not happened due to the coronavirus disease pandemic: a systemic perspective on policy change

2022 ◽  
Author(s):  
Christoph Knill ◽  
Yves Steinebach
Keyword(s):  
Policy Change ◽  
Comprehensive Analysis ◽  
Policy Agenda ◽  
Economic Crises ◽  
Policy Area ◽  
Catching Up ◽  
Policy Transformations ◽  
Gains And Losses ◽  
Academic Debate

Abstract The societal and policy transformations associated with the coronavirus disease pandemic are currently subject of intense academic debate. In this paper, we contribute to this debate by adopting a systemic perspective on policy change, shedding light on the hidden and indirect crisis effects. Based on a comprehensive analysis of policy agenda developments in Germany, we find that the pandemic led to profound shifts in political attention across policy areas. We demonstrate that these agenda gains and losses per policy area vary by the extent to which the respective areas can be presented as relevant in managing the coronavirus disease crisis and its repercussions. Moreover, relying on the analysis of past four economic crises, we also find that there is limited potential for catching up dynamics after the crisis is over. Policy areas that lost agenda share during crisis are unlikely to make up for these losses by strong attention gains once the crisis is over. Crises have hence substantial, long-term and so far, neglected effects on policymaking in modern democracies.

Uncertain Technology Evolution and Decision Making in Design

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Jonathan L. Arendt ◽  
Daniel A. McAdams ◽  
Richard J. Malak
Keyword(s):  
Research And Development ◽  
Pareto Frontier ◽  
Evolutionary Process ◽  
Evolutionary Model ◽  
Development Effort ◽  
Technology Evolution ◽  
Curve Model ◽  
S Curve ◽  
Over Time

The potential for engineering technology to evolve over time can be a critical consideration in design decisions that involve long-term commitments. Investments in manufacturing equipment, contractual relationships, and other factors can make it difficult for engineering firms to backtrack once they have chosen one technology over others. Although engineering technologies tend to improve in performance over time, competing technologies can evolve at different rates and details about how a technology might evolve are generally uncertain. In this article we present a general framework for modeling and making decisions about evolving technologies under uncertainty. In this research, the evolution of technology performance is modeled as an S-curve; the performance evolves slowly at first, quickly during heavy research and development effort, and slowly again as the performance approaches its limits. We extend the existing single-attribute S-curve model to the case of technologies with multiple performance attributes. By combining an S-curve evolutionary model for each attribute with a Pareto frontier representation of the optimal implementations of a technology at a particular point in time, we can project how the Pareto frontier will move over time as a technology evolves. Designer uncertainty about the precise shape of the S-curve model is considered through a Monte Carlo simulation of the evolutionary process. To demonstrate how designers can apply the framework, we consider the scenario of a green power generation company deciding between competing wind turbine technologies. Wind turbines, like many other technologies, are currently evolving as research and development efforts improve performance. The engineering example demonstrates how the multi-attribute technology evolution modeling technique provides designers with greater insight into critical uncertainties present in long-term decision problems.

scholarly journals Study on evolution of a predator–prey model in a polluted environment

2021 ◽  
Vol 26 (6) ◽  
pp. 1052-1070
Author(s):  
Bing Liu ◽  
Xin Wang ◽  
Le Song ◽  
Jingna Liu
Keyword(s):  
Body Size ◽  
Function Analysis ◽  
Fitness Function ◽  
Rapid Evolution ◽  
Evolutionary Model ◽  
The Body ◽  
Predator Prey ◽  
Predator Prey Model ◽  
Prey Model

In this paper, we investigate the effects of pollution on the body size of prey about a predator–prey evolutionary model with a continuous phenotypic trait in a pulsed pollution discharge environment. Firstly, an eco-evolutionary predator–prey model incorporating the rapid evolution is formulated to investigate the effects of rapid evolution on the population density and the body size of prey by applying the quantitative trait evolutionary theory. The results show that rapid evolution can increase the density of prey and avoid population extinction, and with the worsening of pollution, the evolutionary traits becomes smaller gradually. Next, by employing the adaptive dynamic theory, a long-term evolutionary model is formulated to evaluate the effects of long-term evolution on the population dynamics and the effects of pollution on the body size of prey. The invasion fitness function is given, which reflects whether the mutant can invade successfully or not. Considering the trade-off between the intrinsic growth rate and the evolutionary trait, the critical function analysis method is used to investigate the dynamics of such slow evolutionary system. The results of theoretical analysis and numerical simulations conclude that pollution affects the evolutionary traits and evolutionary dynamics. The worsening of the pollution leads to a smaller body size of prey due to natural selection, while the opposite is more likely to generate evolutionary branching.

scholarly journals 50 Years of Real Convergence – Without Extractives Dependency and Tax Havens

2021 ◽  
Vol 66 (4) ◽  
pp. 501-516
Author(s):  
Róbert Csoma
Keyword(s):  
World Economy ◽  
Special Focus ◽  
Tax Havens ◽  
Developed Economies ◽  
Common Criteria ◽  
Catching Up ◽  
Real Convergence ◽  
Convergence Process ◽  
The World

In the world economy real convergence cannot be detected in the long term and lack of convergence is discussed in this article. The analysis is based on results and debates of economic growth theory and development studies. Special focus is placed on extractives dependent and tax haven countries and the article concludes that these countries considerably contribute to the partial real convergence process, limited only to some regions of the world economy. This paper also studies some common criteria of the catching-up process of emerging countries to developed economies. It concludes that although the factors of catching-up can be very unique in countries at different levels of development, yet there are some factors without which catching-up is hardly feasible nowadays in any country.

A theory of global economic growth in the very long-run: is a grand innovation slowdown inevitable?

2020 ◽  
Vol 6 (53) ◽  
pp. 175-188
Author(s):  
Stanislaw Gomulka
Keyword(s):  
Developed Countries ◽  
World Population ◽  
Extended Model ◽  
Balanced Growth ◽  
Catching Up ◽  
Long Run ◽  
Per Capita ◽  
Global Economic Growth ◽  
Qualitative Changes

AbstractThe paper shows how the original semi endogenous and balanced growth model of Phelps (1966), and my extended version of it (Gomulka, 1990), could be useful in explaining the key ‘stylized facts’ of global long-term growth so far, and in predicting its dynamics in the future. During the last two centuries the sector of R&D and education, producing qualitative changes, has been expanding in the world’s most developed countries much faster than the sector producing conventional goods. The extended model is used to explore and evaluate. the consequences for the global long-term growth of the end of this unbalanced growth, of the completion of the catching up by most of the world’s less developed countries, and of the expected eventual stabilization of the size of the world population. The theory yields a thesis, new in the literature, that the rate of global per capita GDP growth will eventually return to the historically standard very low level, thus implying that the world’s technological revolution is going to be an innovation super-fluctuation.

World Economy: Forecast for the Year 2050

2008 ◽  
pp. 62-79 ◽  
Author(s):  
V. Klinov
Keyword(s):  
International Relations ◽  
World Economy ◽  
Think Tanks ◽  
Geographic Structure ◽  
Catching Up ◽  
The World ◽  
Crucial Problem ◽  
Demographic Processes ◽  
Long Term Trends

Forecasting long-term trends in the world economy is a necessary element of elaborating a strategy of economic development. The forecast for 2025 and 2050 has been worked out using concepts of Kondratieff long waves, catching-up pathways of development as well as modern trends in demographic processes. The estimates of changes in the geographic structure of the world economy, so derived, are compared with forecasts based on extrapolation of trends in the last 30 years of the 20th century, made up by prominent think tanks. The formation of the multi-center structure of the world economy and probable emergence of Russia as one of the global powers may imply that worldwide cooperation in securing supply of natural resources and protecting the environment will become a crucial problem of international relations.

The Internationalisation of German Companies' R&D

1998 ◽  
Vol 163 ◽  
pp. 99-115 ◽  
Author(s):  
John Cantwell ◽  
Rebecca Harding
Keyword(s):  
German Economy ◽  
Motor Vehicles ◽  
Research And Innovation ◽  
Innovation Infrastructure ◽  
Catching Up ◽  
The Usa ◽  
Long Term Trends ◽  
Key Industries ◽  
Corporate Level

Research and development in the German economy is internationalising: recently there has been an increase in outward DFI by German companies relative to the inward DFI of foreign-owned companies in Germany. By examining the long term trends in patents granted in the USA to the world's largest firms between 1969 and 1995, it emerges that Germany is now catching-up with a world-wide trend to internationalise technological activaty, and has done this on the basis of its core technological strengths developed historically at a national and corporate level. The research and innovation infrastructure of the economy remains strong, and German companies are locating abroad in the industries which are the most science-based, which are supportive of domestically-based core technologies and in which they hold the strongest competitive position relative to other European firms. German-owned companies retain their dominance of German-located R & D in five key industries—electronics, chemicals, pharmaceuticals, metals and motor vehicles—and they have developed technological specialisms clearly focused on the core technologies of these industries, at home and now also abroad.

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