This study assesses the effect of human capital expansion on China's export product quality.It employs the difference-in-differences(DID)framework based on a quasi-natural experiment investigating the 1999 higher ...This study assesses the effect of human capital expansion on China's export product quality.It employs the difference-in-differences(DID)framework based on a quasi-natural experiment investigating the 1999 higher education enrollment expansion as the exogenous policy shock.The empirical results confirm that human capital expansion appreciably improved the quality of China's export products.Human capital expansion promoted the transformation and upgrading of old products and the development of new products in term of intensive margin;it strengthened the endowment advantages of incumbent high-quality export enterprises while preventing low-quality enterprises from entering the market through price competition on the extensive margin.This prevented quality decline.Further,the study reveals that the improvement effect driven by human capital came from both innovation-induced and managerial efficiency improvement channels and was more prominent for large or foreign-funded enterprises in the eastern region.Our findings highlight the role of human capital in China's remarkable export performance from an endogenous growth perspective.展开更多
Heavy metals are widely concerning because of their toxicity,persistence,non-degradation and bioaccumulation ability.Iluman health ambient water quality criteria(AWQC)are specific levels of chemicals that can occur in...Heavy metals are widely concerning because of their toxicity,persistence,non-degradation and bioaccumulation ability.Iluman health ambient water quality criteria(AWQC)are specific levels of chemicals that can occur in water without harming human health.At present,most countries do not consider the effects of aquatic vegetables in deriving human health AWQC.Therefore,the intake of aquatic vegetables(Brasenia schreberi)was added to the derivation of human health AWQC and a health risk assessment for 13 heavy metals in Taihu Lake.The human health AWQC(consumption of water,fish and aquatic vegetables)values of 13 heavy metals ranged from 0.04(Cd)to 710.87μg/L(Sn),and the intake of B.schreberi had a very significant effect on the human health AWQC for Cu,with a more than 62-fold difference.The hazard quotients of As(2.8),Cd(1.6),Cr(1.4)and Cu(4.86)were higher than the safe level(HQ=1),indicating that As,Cd,Cr and Cu in Taihu Lake posed a significant health risk.Sensitivity analysis showed that the contribution rate of B.schreberi intake to the human health risk from Cu was 91.6%,and all results indicated that the risk of Cu in B.schreberi to human health should be of particular concern.This study adds the consideration of aquatic vegetable consumption to the traditional method of human health AWQC derivation and risk assessments for the first time,and this approach can promote the development of risk assessments and water quality criteria.展开更多
基金This study is supported by the Projects of National Natural Science Foundation of China(Nos.72163016 and 71963017).
文摘This study assesses the effect of human capital expansion on China's export product quality.It employs the difference-in-differences(DID)framework based on a quasi-natural experiment investigating the 1999 higher education enrollment expansion as the exogenous policy shock.The empirical results confirm that human capital expansion appreciably improved the quality of China's export products.Human capital expansion promoted the transformation and upgrading of old products and the development of new products in term of intensive margin;it strengthened the endowment advantages of incumbent high-quality export enterprises while preventing low-quality enterprises from entering the market through price competition on the extensive margin.This prevented quality decline.Further,the study reveals that the improvement effect driven by human capital came from both innovation-induced and managerial efficiency improvement channels and was more prominent for large or foreign-funded enterprises in the eastern region.Our findings highlight the role of human capital in China's remarkable export performance from an endogenous growth perspective.
基金This work was supported by the National Science and Technology Project of Water Pollution Control and Abatement of China(Grant No.2017ZX07301002-02)the Project of Chinese Research Academy of Environmental Sciences(Grant No.2020YSKY-007)the National Natural Science Foundation of China(Grant No.41521003).
文摘Heavy metals are widely concerning because of their toxicity,persistence,non-degradation and bioaccumulation ability.Iluman health ambient water quality criteria(AWQC)are specific levels of chemicals that can occur in water without harming human health.At present,most countries do not consider the effects of aquatic vegetables in deriving human health AWQC.Therefore,the intake of aquatic vegetables(Brasenia schreberi)was added to the derivation of human health AWQC and a health risk assessment for 13 heavy metals in Taihu Lake.The human health AWQC(consumption of water,fish and aquatic vegetables)values of 13 heavy metals ranged from 0.04(Cd)to 710.87μg/L(Sn),and the intake of B.schreberi had a very significant effect on the human health AWQC for Cu,with a more than 62-fold difference.The hazard quotients of As(2.8),Cd(1.6),Cr(1.4)and Cu(4.86)were higher than the safe level(HQ=1),indicating that As,Cd,Cr and Cu in Taihu Lake posed a significant health risk.Sensitivity analysis showed that the contribution rate of B.schreberi intake to the human health risk from Cu was 91.6%,and all results indicated that the risk of Cu in B.schreberi to human health should be of particular concern.This study adds the consideration of aquatic vegetable consumption to the traditional method of human health AWQC derivation and risk assessments for the first time,and this approach can promote the development of risk assessments and water quality criteria.
