A WORLD OF CITIES: THE CAUSES AND CONSEQUENCES OF URBANIZATION IN POORER COUNTRIES

Historically, urban growth required enough development to grow and transport significant agricultural surpluses or a government effective enough to build an empire. But there has been an explosion of poor mega‐cities over the last 30 years. A simple urban model illustrates that in closed economies, agricultural prosperity leads to more urbanization, but that in an open economy, urbanization increases with agricultural desperation. The challenge of developing world mega‐cities is that poverty and weak governance reduce the ability to address the negative externalities that come with density. This paper models the connection between urban size and institutional failure, and shows that urban anonymity causes institutions to break down. For large cities with weak governments, draconian policies may be the only way to curb negative externalities, suggesting a painful trade‐off between dictatorship and disorder. A simple model suggests that private provision of infrastructure to reduce negative externalities is less costly when city populations are low or institutions are strong, but that public provision can cost less in bigger cities.     

A Causality Analysis of Economic Growth and Union Density in European Countries

In this paper, we analyse the relationship between union density and economic growth using a Granger causality analysis and shocks analysis with vector autoregression model. We find that the Granger causality goes from the growth rate to the unionization rate in four of the 11 European countries under study. France bucks the trend: it is the only country in which union density influences economic growth, moreover in a positive way.     

CREDIT CONSTRAINTS AND THE CYCLICALITY OF R&D INVESTMENT: EVIDENCE FROM FRANCE

We use a French firm‐level data set containing 13,000 firms over the period 1994–2004 to analyze the relationship between credit constraints and firms’ R&D behavior over the business cycle. Our main results can be summarized as follows: (i) R&D investment is countercyclical without credit constraints, but it becomes procyclical as firms face tighter credit constraints; (ii) this result is only observed for firms in sectors that depend more heavily upon external finance, or that are characterized by a low degree of asset tangibility; (iii) in more credit‐constrained firms, R&D investment plummets during recessions but does not increase proportionally during upturns.     

组织支持感对研发人员创新行为的影响：创造力效能感与积极情绪的中介作用

组织支持感对个体创新行为具有重要影响,但其中的影响机制值得深入探究。本研究基于组织支持感理论,同时从认知和情绪视角切入,将创造力效能感和积极情绪引入到组织支持感与研发人员创新行为的关系分析框架中。采用自填问卷法调查了248名研发人员,在检验了同源方差和问卷信效度的基础上,通过结构方程建模（SEM）方法检验了研究假设,结果发现：①在中国情境下,组织支持感对研发人员创新行为有显著正向影响,组织支持感及其各维度对研发人员创新行为有预测力,其中主管支持的预测力最强;②创造力效能感对研发人员创新行为有显著正向影响,并在研发人员组织支持感与创新行为间起部分中介作用;③积极情绪对研发人员创新行为有显著正向影响,在组织支持感与研发人员创新行为间起部分中介作用;④将创造力效能感和积极情绪同时纳入中介模型后,两者的中介作用完全解释了组织支持感对研发人员创新行为的影响。     

国内核电公众沟通研究热点及发展趋势——基于CiteSpace的知识图谱分析

文章以中国学术期刊网络出版总库(CNKI)2000—2021年发表的396篇核电公众沟通相关文献为基础,运用CiteSpace5.7R1软件,进行发文量统计、合作共现、关键词聚类、突现词探测等分析,揭示出国内核电公众沟通研究主要聚焦核电政策宣贯与技术知识普及、核电公众沟通与接受机理两大主题,沟通重心由“核事故处置”向“核应急预防”转变,沟通思路由“单向宣传”向“双向互动”转变并朝“构建核安全共同体”迈进。同时发现,国内核电公众沟通研究仍属小众领域,与我国从核大国迈向核强国的现实需求不相称,亟待更多学者广泛参与,推动学科交叉融合,增强研究系统性,提升学术影响力。     

SEIR Model to address the impact of face masks amid COVID-19 pandemic

Early in the pandemic of coronavirus disease 2019 (COVID-19), face masks were used extensively by the general public in several Asian countries. The lower transmission rate of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Asian countries compared with Western countries suggested that the wider community use of face masks has the potential to decrease transmission of SARS-CoV-2. A risk assessment model named Susceptible, Exposed, Infectious, Recovered (SEIR) model is used to quantitatively evaluate the potential impact of community face masks on SARS-CoV-2 reproduction number (R₀) and peak number of infectious persons. For a simulated population of one million, the model showed a reduction in R₀ of 49% and 50% when 60% and 80% of the population wore masks, respectively. Moreover, we present a modified model that considers the effect of mask-wearing after community vaccination. Interestingly mask-wearing still provided a considerable benefit in lowering the number of infectious individuals. The results of this research are expected to help public health officials in making prompt decisions involving resource allocation and crafting legislation.