Impact of digital economy development on carbon productivity:An empirical analysis based on threshold effect and spatial spillover effect

Utilizing provincial panel data from 2014 to 2020,this study employs a fixed effect model,a threshold effect model,and a spatial lag model to empirically examine the correlation between digital economic development and carbon productivity.The findings indicate that digital economic development significantly contributes to the enhancement of carbon productivity in the long term.Furthermore,through instrumental variable method,replacement of explanatory variables and other methods to test its endogeneity and stability,the results remain robust.In terms of regional heterogeneity,the impact of digital economic development on carbon productivity is less pronounced in the central and western regions compared to the eastern region.Additionally,further investigation reveals that industrial structure upgrading and science and technology investment level exhibit different threshold effects on the influence of digital economy development level on carbon productivity.Moreover,there is a significant spatial spillover effect of digital economy development on carbon productivity with H-H and L-L agglomeration spatial correlation.

Research on the Threshold Effect of China’s Pharmaceutical Export Trade on Internal and External R&D Investment

Objective To study the threshold effect of export trade on internal and external R&D investment in China’s pharmaceutical industry,and to provide reference for some pharmaceutical enterprises to improve the investment.Methods The panel data of pharmaceutical industry in 25 provinces and cities in China from 2009 to 2019 were selected to conduct empirical analysis by establishing a threshold regression model,and a better export trade interval was obtained.Results and Conclusion There is a threshold value for the effect of new product export on both internal and external R&D expenditures,and the threshold values are 845.2788 million yuan and 318.4198 million yuan,respectively.There is a single threshold effect of export trade on both internal and external R&D investment in China’s pharmaceutical industry,and the effect of export trade on internal and external R&D investment changes from negative to positive as the export trade develops from low to high.

Research on the Impact of China’s Foreign Trade Technology Spillover on Green Total Factor Productivity of Countries Along the“Belt and Road”:Based on the Institutional Quality Threshold Effect

China’s growing trade with countries along the“Belt and Road”Initiative is accompanied by a focus on green development.Based on the panel data from 2007 to 2018,this paper establishes a threshold regression model to empirically analyze the institutional quality threshold effect of China’s foreign trade technology spillover on the GTFP of countries along the“Belt and Road.”The results show that China’s foreign trade technology spillover has a significant institutional quality double threshold effect on the green total factor productivity of the countries along the“Belt and Road.”As the institutional quality of the countries along the“Belt and Road”crosses a specific threshold value,the impact of China’s foreign trade technology spillover on the green total factor productivity of the countries along the“Belt and Road”has a significant positive promoting effect,and corresponding suggestions are put forward.

Productivity Spillovers from FDI in China:Regional Differences and Threshold Effects

Economic theory posits numerous channels through which FDI might create positive spillovers for domestic firms. However, the results of empirical studies that have sought to document these spillovers have been mixed. One explanation for this variation is that the capacity of domestic firms to absorb spillovers might vary. In the present paper, we explore these issues in the case of China. ,4side from being one of the world＇s leading hosts offoreign direct investment, China makes for an interesting case study because its provinces vary greatly with respect to those factors most commonly held to influence absorptive capacity, such as the initial level of technology in domestic firms. This paper begins by empirically establishing that the spillovers from foreign direct investment do indeed vary across provinces. Threshold values for varioas factors that influence absorptive capacity factors are then estimated and it is found that conditions in many provinces presently fall short of these values. This provides an obvious focus of attention for China＇s policy-makers.

Impact of coupling coordination development of port and city environments on urban economic competitiveness:Evidence from the coastal port cities in eastern China

Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.

Does China's digital economy contribute to low-carbon transition?

The digital economy,as a new emerging economic form,has become an important power for realizing Chinese-style modernization and promoting green development in China.This paper measures the digital economy and low-carbon transition index based on the data of 30 provinces in China from 2013 to 2020 and analyzes the mechanism and path of the digital economy affecting low-carbon transition using the fixed effect panel data model and the threshold effect model.It is found that,(1)The digital economy and low-carbon transition in China are various in different regions,with characteristics of being unbalanced and insufficient.(2)The digital economy significantly promotes low-carbon transition,with the greatest influence in the Central region,followed by the Eastern region and the Western region.Under different dimensions,the development of informatization and digital transactions promote low-carbon transition,but the development of the internet plays an inhibiting role.(3)The higher the degree of urbanization and environmental regulation,the greater the influence of the digital economy on low-carbon transition.

Tourism dependence and poverty alleviation thresholds in Chinese ethnic tourism

Questions persist on the relationship between tourism dependence and economic growth in ethnic tourism areas.This study addresses such gaps by constructing a threshold regression model based on socio-economic data from 2006 to 2019 for nine sites in Enshi Prefecture of central China.Arc GIS and other open-source data were also used to visualize changing tourism resources in the region.Findings suggest that tourism dependence(the ratio of tourism-based GDP to overall GDP)significantly promotes economic growth in ethnic minority areas.However,the positive influence of tourism dependence on economic growth appears dynamic and non-linear–rising at first before falling when tourism dependence exceeded a threshold of 34%,with effects varying by site and year.Methods and findings make crucial theoretical contributions to understanding tourism dependence and poverty alleviation linkages.This paper also highlights the importance of political support and balanced investment in diverse industries to minimize decreasing returns beyond tourism dependence thresholds in destinations worldwide.

Sustainability of Public Debt and Economic Growth in Cote d’Ivoire:is There a Threshold Effect?

The development of Ivorian public debt in recent years has raised concerns.Is its current level capable of boosting the economy or,on the contrary,being at the source of a recession?This paper analyzes the effect of the level of indebtedness on economic growth in Côte d’Ivoire using the Threshold Autoregressive(TAR)model over the period 1970-2018.The results obtained in the short run shed light on the no relationship between public debt and economic growth.In the long run,on the other hand,there is a bi-directional granger causality between public debt and the sustainability of economic growth.The non-linearity between the variables of interest has been studied and the results show the presence of a threshold effect:beyond 48.03 percent of GDP,any increase in public debt by 1%should reduce economic growth by 0.28%.Thus,the study questions the relevance of the criterion set by the WAEMU:public debt<70%of GDP.

Fiscal Expenditure Structure and Environmental Pollution：Empirical Research Based on the Panel Threshold Model

Based on China＇s provincial panel data from 2004 to 2014,the net effect and threshold characteristics of local governments＇ fiscal expenditure structure on environmental pollution were tested with the nonlinear panel threshold model. The results showed that the net effect of fiscal expenditure structure on regional pollution emission intensity had significant inverted V-shaped single threshold characteristics. Besides,the threshold value of economic density was 6. 039 6 million yuan/km^2,and that of population density was 201 people/km^2. That is,the fiscal expenditure structure inclining to productive expenditure was relatively conducive to the promotion of pollution reduction in the areas with low economic density or low population density. The fiscal expenditure structure inclining to non-productive expenditure was relatively conducive to the promotion of pollution reduction in the areas with high economic density or high population density.

Research on the Impact of Financial Development on TFP—— DEA-Malmquist Index and Hansen Threshold Model Based on Panel Data of Shandong Province, China

Shandong’s TFP growth is higher than Chinese average,but the growth rate has slowed in recent years,appearing the phenomenon that the growth momentum of Shandong’s TFP is insufficient.Using DEA-Malmquist Index to measure Shandong’s TFP growth rate,empirical research from the perspective of financial development finds that financial scale,efficiency of financial institutions,fiscal intervention,and scale of foreign capital utilization have significant nonlinear effects on the growth of TFP.Furtherly,through threshold analysis,the efficiency of financial institutions has a significant threshold effect on TFP growth.Financial scale and fiscal intervention are the main core variables that affect the growth of TFP under the threshold effect,and they have the same effect direction on TFP before and after the threshold value.However,the effect intensity of these two core variables on TFP is different.

Effect of β_3-adrenoceptors on Ventricle Fibrillation Threshold and Effective Refractory Period in Rats With Heart Failure

Objectives To observe the effect of β3-Adrenoceptor （AR） on ventricle fibrillation threshold （VFT） and effective refractory period （ERP） in rats with heart failure. Methods Rats were randomized into control group and heart failure group. The expression of β3-ARmRNA was detected with RTPCR; The VFT, ERP, LVESP,LVEDP, ＋dp/dtmax and -dp/dtmax was measured at the same time with administration of BRL37344 （ 2 nmol / kg, β3- AR agonist）. Results ①Both the expression of β3-AR mRNA and the proportion increased in rats with heart failure in comparison with control rats （0.028 vs. 0.011 and 5.4% vs 1.2%, P 〈 0.05）;② ERP was longer in rats with heart failure than control group （70.5±5.5 ms vs 59.5±6.4ms, P 〈 0.05） and there was no difference of ERP in rats with heart failure with administration of BRL37344 （73.0±4.8 ms vs 70.5± 5.5 ms, P 〉0.05）; ③VFT was lower in rats with heart failure than control group（10.9±0.8 mv vs 30.5± 1.3 mv, P〈 0.05） and decreased obviously in rats with heart failure with administration of BRL37344 （7.1±0.6 mv vs 10.9±0.8 mv, P 〈 0.05） ; The decrease of VFT correlated with the effect on LVESP, ＋dp/ dtmax,-dp/dtmax of BRL37344 and the expression of β3-AR mRNA （correlation coefficient： 0.788, 0.708, 0.759, 0.787; P 〈 0.05）. Conclusions The expression of β3-AR mRNA of left ventricle was obviously increased in rats with heart failure, and activation of β3-AR had no effect on ERP but could decreased VFT which correlated with the effect of β3-AR on LVESP, ＋dp/dtmax, -dp/dtmax and the expression of β3-AR mRNA.

Soil microbial communities regulate the threshold effect of salinity stress on SOM decomposition in coastal salt marshes

Salinity stress is one of the critical environmental drivers of soil organic matter(SOM)decomposition in coastal ecosystems.Although the temperature sensitivity(Q_(10))of SOM decomposition has been widely applied in Earth system models to forecast carbon processes,the impact of salinity on SOM decomposition by restructuring microbial communities remains uncovered.Here,we conducted a microcosm experiment with soils collected from the coastal salt marsh in the Yellow River Estuary,which is subjected to strong dynamics of salinity due to both tidal flooding and drainage.By setting a gradient of salt solutions,soil salinity was adjusted to simulate salinity stress and soil carbon emission(CO_(2))rate was measured over the period.Results showed that as salinity increased,the estimated decomposition constants based on first-order kinetics gradually decreased at different temperatures.Below the 20‰salinity treatments,which doubled the soil salinity,Q_(10)increased with increasing salinity;but higher salinity constrained the temperature-related response of SOM decomposition by inhibiting microbial growth and carbon metabolisms.Soil bacteria were more sensitive to salinity stress than fungi,which can be inferred from the response of microbial beta-diversity to changing salinity.Among them,the phylotypes assigned to Gammaproteobacteria and Bacilli showed higher salt tolerance,whereas taxa affiliated with Alphaproteobacteria and Bacteroidota were more easily inhibited by the salinity stress.Several fungal taxa belonging to Ascomycota had higher adaptability to the stress.As the substrate was consumed with the incubation,bacterial competition intensified,but the fungal co-occurrence pattern changed weakly during decomposition.Collectively,these findings revealed the threshold effect of salinity on SOM decomposition in coastal salt marshes and emphasized that salt stress plays a key role in carbon sequestration by regulating microbial keystone taxa,metabolisms,and interactions.

The effects of smoking on temporary threshold shift

For studying the influence of smoking on temporary threshold shift (TTS), six normal subjects (3 smokers and 3 nonsmokers) were selected for carrying out this work. Nonsmokers were exposed separately for 7 min to 95 dB SPL in 1/3-octave band filtered noise centred at 2 kHz. Pre and post exposure thresholds (leftear) were recorded in a sound-proof booth using Bruel & Kjaer (B & K) Audiometer type 1800. For smokers, each one smoked a cigarette during the five minutes following the pre-exposure threshold measurement. All the assessments were conducted at a temperature between 22-25℃. The results indicated that smokers evidenced less TTS than did nonsmokers in the frequency range from 1 kHz to 5 kHz. At 6 kHz smokers evidenced nearly higher value. Maximum TTS was attained at frequency that was about 1/2-octave higher than that of the exposed noise. Comparison between recovery curves for smokers and nonsmokers was also made.

On the structure in the ΛN cross section at the ∑N threshold

The complexity of threshold phenomena is exemplified on a prominent and long-known case-the structure in theΛp cross section(invariant mass spectrum)at the opening of the∑N channel.The mass splitting between the∑baryons together with the angular momentum coupling in the^(3)S_(1)-^(3)D_(1)partial wave imply that,in principle,up to six channels are involved.Utilizing hyperon-nucleon potentials that provide an excellent description of the available low-energy Λp and∑N scattering data,the shape of the resulting Λp cross section is discussed and the poles near the ∑N threshold are determined.Evidence for a strangeness S=-1 dibaryon is provided,in the form of a(unstable)∑N bound state in the vicinity of the ∑N threshold.Predictions for level shifts and widths of ∑^(-)p atomic states are given.

Manufacturing Demand and Producer Services Efficiency in China:Threshold Effect of Economic Development

Considering the important role the demand from manufacturing has played in the development of producer services,this paper analyzes the influence mechanism of manufacturing demand on producer services efficiency through two channels,which are the scale effect and innovation incentives.Meanwhile,the paper also evaluates the moderating effect of economic development level on the relationship between manufacturing demand and producer services efficiency.Based on the panel data of China’s manufacturing industry and producer services from 1995 to 2014,the empirical result shows that:(1)the demand from manufacturing was helpful to improve producer services efficiency,and compared with the labor-intensive manufacturing,the demand from capital-intensive manufacturing played a more important role in improving producer services efficiency;(2)at different stages of economic development,the promoting effect of manufacturing demand on producer services efficiency showed a nonlinear threshold effect rather than a simple linear effect,namely after crossing a certain threshold of economic development level,the promoting effect would be more significant.More specifically the threshold level faced by capital-intensive manufacturing industry was higher than that faced by labor-intensive manufacturing industry.These findings may be helpful for governments to make industrial development strategy.

经济发展对城市宜居性的影响——基于中国40个大中城市的实证分析

Under the background that economy and urbanization of China are gradually entering the stage of high-quality development,clarifying the influence of economic development on urban livability is of significant academic and practical value.In this paper,regarded as one“factor”,livability was introduced into the research framework of production function,and a theoretical model of the impact of economic development on urban livability was established.Based on the panel data of 40 cities in China from 2005 to 2019,the System GMM,panel threshold model and other methods were further adopted to carry out an empirical analysis.The results show that:(1)The livability level of large and medium-sized cities in China from 2005 to 2019 has been rising generally,but they present obvious characteristics of dimensional and spatial differentiation.(2)In general,economic development has an inhibiting effect on the improvement of urban livability,but this logical effect shows obvious heterogeneity in different time periods and diverse city scales.This inhibitory effect is more significant for the cities before entering the new normal phase of economy,and large-scale municipalities and economically-developed provincial capitals(namely Class-A cities).(3)There are significant threshold effects in the impact of economic development on urban livability,where the threshold variables are income level and economic development.With the increase of city dwellers’income,this effect presents an inverted N-shaped nonlinear feature.When the development of economy makes the average wage of employees between 60,000and 80,000 yuan,economic development can significantly improve urban livability.Also,there is a significant single threshold inhibitory effect when economic development is taken as a threshold variable.However,its negative impact shows a law of diminishing marginal efficiency.In addition,a similar threshold effect is found in smaller-scale Class-B cities.The findings of this research can provide some insights for urban planners and policymakers in both China and vast developing countries to understand better the relationship between economic development and urban livability.Finally,according to the research findings,we proposed the corresponding policy enlightenment from both“macro guidance”and“micro action”.

On the monolayer dispersion behavior of Co_(3)O_(4)on HZSM-5 support:designing applicable catalysts for selective catalytic reduction of nitrogen oxides by ammonia

Based on monolayer dispersion theory,Co_(3)O_(4)/ZSM-5 catalysts with different loadings have been prepared for selective catalytic reduction of nitrogen oxides by ammonia.Co_(3)O_(4)can spontaneously disperse on HZSM-5 support with a monolayer dispersion threshold of 0.061 mmol 100 m^(-2),equaling to a weight percentage around 4.5%.It has been revealed that the quantities of surface active oxygen(O_(2)^(-))and acid sites are crucial for the reaction,which can adsorb and activate NO_(x)and NH_(3)reactants effectively.Below the monolayer dispersion threshold,Co_(3)O_(4)is finely dispersed as sub-monolayers or monolayers and in an amorphous state,which is favorable to generate the two kinds of active sites,hence promoting the performance of ammonia selective catalytic reduction of nitrogen oxide.However,the formation of crystalline Co_(3)O_(4)above the capacity is harmful to the reaction performance.4%Co_(3)O_(4)/ZSM-5,the catalyst close to the monolayer dispersion capacity,possesses the most abundant active O_(2)^(-)species and acidic sites,thereby demonstrating the best reaction performance in all the samples.It is proposed the optimal Co_(3)O_(4)/ZSM-5 catalyst can be prepared by loading the capacity amount of Co_(3)O_(4)onto HZSM-5 support.

块体择优取向纳米孪晶铜的优异抗疲劳裂纹扩展性能

本文研究了具有不同微观结构(如晶粒尺寸和孪晶厚度)的块体择优取向纳米孪晶Cu(NT-Cu)的疲劳裂纹扩展(FCG)特性,着重讨论了裂纹闭合效应和近门槛值区域的本征FCG阻力.与传统无孪晶的粗晶Cu相比,NT-Cu样品表现出显著提升的疲劳裂纹扩展抗力(有效门槛值应力强度因子范围,△K_(th,eff)).这种增强的裂纹扩展阻力与NT-Cu中特殊的跨孪晶位错滑移模式有关.该位错主导着NT-Cu裂纹尖端的循环变形,有效降低了裂纹尖端循环滑移不可逆水平,从而提高了纳米孪晶材料损伤扩展的本征抗力.

Prevalence of vitamin D deficiency in girls with idiopathic central precocious puberty

The relationship between vitamin D deficiency and idiopathic central precocious puberty （ICPP） has been recently documented. In this study, 280 girls diagnosed with ICPP and 188 normal puberty control girls of similar ages were enrolled and retrospectively studied. The ICPP group had significantly lower serum 25- hydroxyvitamin D （25[OH]D） levels than the control group. Furthermore, a nonlinear relationship was found between serum 25[OH]D and ICPP, and a cut-offpoint for serum 25[OH]D was found at 31.8 ng/ml for ICPP with and without adjusting the different confounding factors. Girls with serum 25[OH]D 〉~ 31.8 ng/ml had a lower odds ratio （unadjusted： OR 0.36, 95% CI 0.15 to 0.83, P 〈 0.05; height and weight adjusted： OR 0.44, 95~0 CI 0.18 to 1.08, P = 0.072; BMI adjusted： OR 0.36, 95% CI 0.16 to 0.84, P 〈 0.05）. The ICPP subjects with 25[OH]D deficiency had a higher body mass index （BMI） than the subjects from the two other subgroups. Correlation analysis showed that vitamin D level is correlated with BMI and some metabolic parameters in the ICPP group. Our study suggested that vitamin D status may be associated with ICPP risk and may have a threshold effect on ICPP.