The Effect of Urban Agglomeration Expansion on PM_(2.5) Concentrations: Evidence from a Quasi-natural Experiment

This study constructs a quasi-natural experiment based on the expansion of the Yangtze River Delta urban agglomeration(YRDUA) of China in 2010 to investigate the impact and inner mechanism of urban agglomeration expansion on fine particulate matter(PM_(2.5)) concentrations through propensity scores in difference-in-differences models(PSM-DID) using panel data from 286 prefecturelevel cities in China from 2003 to 2016. The results show that 1) urban agglomeration expansion contributes to an overall decrease in PM_(2.5)concentration, which is mainly achieved from the original cities. For the new cities, on the other hand, the expansion significantly increases the local PM_(2.5)concentration. 2) In the long term, the significant influence of urban agglomeration expansion on PM_(2.5)concentration lasts for three years and gradually decreases. A series of robustness tests confirm the applicability of the PSM-DID model.3) Cities with weaker government regulation, a better educated population and higher per capita income present stronger PM_(2.5)reduction effects. 4) Urban agglomeration expansion affects the PM_(2.5)concentration mainly through industrial transfer and population migration, which cause a decrease in the PM_(2.5)concentration in the original cities and an increase in the PM_(2.5)concentration in the new cities.Corresponding policy suggestions are proposed based on the conclusions.

Environmental regulation and firms'performance:a quasi-natural experiment from China

This paper investigates whether environmental regulation affects firm's performance including productivity,wage and employment using firm-level data in 1996-2007.The identification uses Two Control Zones(TCZ)policy implemented by the Chinese government in 1998,in which tougher environmental regulations were imposed in TCZ cities but not others.By difference-indifferences estimation,we find that tougher environmental regulation leads to larger increase on both total factor productivity and wage,and firms tend to employ fewer workers under pressure of environmental protection.Heterogeneous tests show that the impacts are better for nonpollution intensive firms,non-exporters and SOEs.Finally,we find that R&D input and exiting firms among industry are the driving forces for enhancing TFP and increasing wage and unemployment.

Pharmacological interventions for improved colonic anastomotic healing:A meta-analysis

AIM:To identify pharmaceuticals for the prophylaxis of anastomotic leakage(AL),we systematically reviewed studies on anastomosis repair after colorectal surgery.METHODS:We searched PubMed and EMBASE for articles published between January 1975 and December 2012.We included studies in English with the primary purpose of promoting healing of anastomoses made in the colon or rectum under uncomplicated conditions.We excluded studies on adverse events from interventions,nutritional interventions or in situ physical supporting biomaterials.The primary outcome was biomechanical strength or AL.We performed meta-analyses on therapeutic agents investigated by three or more independent research groups using the same outcome.The DerSimonian-Laird method for random effects was applied with P < 0.05.RESULTS:Of the 56 different therapeutic agents assessed,7 met our inclusion criteria for the metaanalysis.The prostacyclin analog iloprost increased the weighted mean of the early bursting pressure of colonic anastomoses in male rats by 60 mmHg(95%CI:30-89) vs the controls,and the immunosuppressant tacrolimus increased this value by 29 mmHg(95%CI:4-53) vs the controls.Erythropoietin showed an enhancement of bursting pressure by 45 mmHg(95%CI:14-76).The anabolic compound growth hormone augmented the anastomotic strength by 21 mmHg(95%CI:7-35),possibly via the up-regulation of insulin-like growth factor-1,as this growth factor increased the bursting pressure by 61 mmHg(95%CI:43-79) via increased collagen deposition.Hyperbaric oxygen therapy increased the bursting pressure by 24 mmHg(95%CI:13-34).Broad-spectrum matrix metalloproteinase inhibitors increased the bursting pressure by 48 mmHg(95%CI:31-66) on postoperative days 3-4.In the only human study,the AL incidence was not significantly reduced in the 103 colorectal patients treated with aprotinin(11.7%) compared with the 113 placebo-treated patients(9.7%).CONCLUSION:This systematic review identified only one randomized clinical trial and seven therapeutic agents from pre-clinical models that could be explored further for the prophylaxis of AL after colorectal surgery.

Short-sale refinancing and price adjustment speed to bad news: Evidence from a quasi-natural experiment in China

Short selling may accelerate stock price adjustment to negative news.However,the literature provides mixed evidence for this prediction.Using short-sale refinancing and a staggered difference-in-differences(DID)model,this paper explores the effect of short selling on stock price adjustment.Our results show that(1)short-sale refinancing improves the speed of stock price adjustment to negative news.This result holds after we control for endogeneity.(2)The positive relationship between short-sale refinancing and stock price adjustment speed is significant in subsamples of stocks with higher earnings management or lower accuracy of analyst forecasts,indicating that firms with more opaque information are more likely to be targeted by short sellers.In subsamples of stocks with a higher ownership concentration or lower ownership by institutional investors,short selling is more likely to increase the speed of stock price adjustment,indicating that ownership structure may influence negative news mining.(3)As short-sale refinancing exacerbates the absorption of bad news by stock prices,it increases crash risk.This study enriches the research on the economic consequences of short selling and provides empirical evidence supporting regulations on short selling in China.

The Belt and Road Initiative and Financing Constraint for Chinese Enterprises

In the context of China’s proactive implementation of the Belt and Road Initiative(BRI),unraveling the BRI’s effect on corporate behavior is of vital importance to China’s policymaking on overseas investment.With the BRI’s enactment as a quasi-natural experiment,this paper employs the difference in differences(DID)method to investigate the BRI’s effect on the financing constraint for Chinese enterprises.Our study finds that the BRI’s implementation has significantly reduced financing constraints for BRI enterprises,and the effect is more significant for emerging advantageous industries and export-oriented node cities.

Rural E-commerce and County Economic Development in China

With the proliferation of information and communication technology in rural areas,rural e-commerce has gradually become a new economic phenomenon in China. Usingthe national rural e-commerce comprehensive demonstration policy as a quasi-naturalexperiment, this study examines the causal linkage between rural e-commerce andcounty-level economic development in China. Its findings, which draw on county-levelpanel data from 2011 to 2018, indicate that the policy had a positive effect on the countyleveleconomy in China, resulting in an overall increase in county GDP by 3.5 percent(0.7 percent annually). Our analysis further shows that the impact of the policy diferedalong the region and human capital dimensions. Further analysis reveals that industrialstructure and nonagricultural employment were the main channels for the policy toexert a county-level economic impact. Infrastructure improvement in China also playsan important role. The findings emphasize the importance of advancing e-commerce inrural areas to stimulate county-level economic development.

Fault Tolerance for Corporate Innovation:Evidence from the Reform of State-owned Enterprises

Innovation is the source of power for high-quality development,and a relaxed institutional arrangement is a necessity for promoting innovation in enterprises.This paper examines the impact of fault tolerance on corporate innovation,theoretically analyzes the positive effects of fault tolerance on stimulating innovation,and estimates the influence of fault tolerance on corporate innovation by using the panel data of listed manufacturing companies from 2007 to 2019,taking the quasi-natural experiment of fault-tolerance system in various places since the new round of stateowned enterprise(SOE)reform.This study finds that the fault-tolerance system has significantly improved the R&D investment and patent application of the pilot SOEs,but the incentive effect is mainly reflected in the utility model patents;fault-tolerance system mainly promotes corporate innovation by alleviating managers’career worries and improving governance ability.Furthermore,the fault-tolerance system is more effective for small and medium-sized SOEs with low market competition and can alleviate the restriction of agency cost on corporate innovation.In addition,the fault-tolerance system has not yet had a significant spillover effect on private enterprises.These results show that in the SOE reform,it is necessary to strengthen the institutional arrangement of fault tolerance and create a relaxed environment to encourage innovation;it is necessary to organically integrate fault-tolerancesystem design into executive measurement and corporate governance,promote faulttolerant system to be implemented in a wider range of enterprises,and enhance the incentive effect on high-quality innovation.