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.

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.

Threshold effects of tourism agglomeration on the green innovation efficiency of China's tourism industry

Industrial agglomeration is an essential and effective way to integrate resources and elements. Its impact on the green innovation efficiency of the tourism industry is a process of continuous development and dynamic change. This paper, based on the provincial panel data from 2006 to 2015, uses super SBM model to measure the green innovation efficiency of China's tourism industry.The threshold regression model is employed to conduct empirical tests of the nonlinear threshold effect of agglomeration on the green innovation efficiency of tourism industry. The inter-provincial differences of various threshold effects and their possible causes are analyzed. Results indicate that the green innovation efficiency of China's tourism industry is generally growing, while regional disparity is significant with a gradient decrease along the eastern-central-western regions. There is an obvious positive nonlinear relationship between tourism agglomeration and green innovation efficiency. It is also found that with the increase of agglomeration, its influence is at a high level. As the level of agglomeration crosses the first threshold, its impact is at a low level, and when it crosses the second threshold, the impact of tourism agglomeration is at an intermediate level. Finally, this paper proposes the basic path and some policy recommendations to promote the green innovation efficiency of the tourism industry in China.

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.

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.

The Threshold Effect of Rationalization of Industrial Structure on Air Quality in Shanxi Province

Shanxi Province is a typical resource-based region. After years of economic transformation, the air quality has been at a low level for a long time. The rationalization of industrial structure can measure the effect of economic transformation and whether it has an important impact on air quality. Therefore, it is necessary to study the non-linear impact that the rationalization of industrial structure has had on air quality at different stages, which is of positive significance for the continuing transformation and upgrading of resource-based regions. This study constructs a threshold regression model based on the panel data of 11 provincial cities in Shanxi Province from 2004 to 2016. The results show that the rationalization of industrial structure had a double threshold effect on air quality under different threshold variables. On the whole, optimizing the rationalization of industrial structure in Shanxi Province can improve air quality, and the improvement effect dropped first, and then began to rise. As a result, the current energy transformation and upgrading process should focus on the rationalization of industrial structure to solve the conflict between air quality and economic development.

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.

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.

Developmental Threshold Temperature and Effective Accumulative Tem- perature of Pupae and Eggs of Holcocerus hippophaecolus

In order to understand the occurrence and the developmental regularity of seabuckthorn carpenterworm (Holcocerus hippophaecolus) and predict its population density, the developmental threshold temperature (C) and effective accumulative tem- perature (K) of the carpenterworm pupae and eggs were analyzed under the conditions of constant and variable temperatures. The results show that the values of C and K of the carpenterworm pupae are (12.1 ± 0.2) °C and (295.2 ± 4.1) day-degrees at constant temperatures, and (15.5 ± 0.4) °C and (202.4 ± 13.1) day-degrees at variable temperatures. However, the values of C and K of the eggs at variable temperatures are (16.7 ± 0.8) °C and (101.5 ± 12.6) day-degrees. The differences of developmental threshold and effective accumulative temperature under the conditions of constant and variable temperatures of the carpenterworm pupae accord with the developmental regularity of most insects in nature. By comparing five different constant temperatures, the conclusion is that the optimum developmental temperature of the pupae is 21 °C when both the pupation of the mature larvae and the eclosion of the pupae are very accordant. Moreover, the percentage of eclosion is over 90%. The average developmental durations of the carpenter- worm pupae and eggs are 31 and 16 d at variable temperatures.

Effective accumulated temperature and developmental threshold temperature for Semanotus bifasciatus(Motschulsky) in Beijing

In order to understand the occurrence and development of Semanotus bifasciatus （Motschulsky）, a borer insect of Platycladus orientalis in parts of northern and eastern China and to improve its prediction, the developmental threshold temperature （C1） and effective accumulated temperature （K） of S. bifasciatus were determined under conditions of constant and variable temperatures. The results show that under constant temperatures the value of C1 has a range of 8.90±1.77℃and the value of K lies between 95.19±13.14 degree-day for eggs; the values for larvae are C1= 13.26±3.06℃ and the number of degree-day is K 2,885.07±187.87 degree-day; for pupae the ranges are C1 = 8.93±2.49℃ and K= 131.20±25.63 degree-day. Under the condition of ambient temperatures, the values for eggs are C1= 17.33±1.24℃ and K= 70.79±8.99 degree-day. It is suggested that S. bifasciatus adults over-winter in a state of dormancy, not at a diapause. Warm winter may accelerate the life cycle ofS. bifasciatus. Equations can be used to predict an early occurrence ofS. bifasciatus.

Effects of total dose irradiation on the threshold voltage of H-gate SOI NMOS devices

This work researched the impact of total dose irradiation on the threshold voltage of N-type metal oxide semiconductor field effect transistors(nMOSFETs) in silicon-on-insulator(SOI) technology.Using the subthreshold separation technology,the factor causing the threshold voltage shift was divided into two parts:trapped oxide charges and interface states,the effects of which are presented under irradiation.Furthermore,by analyzing the data,the threshold voltage shows a negative shift at first and then turns to positive shift when irradiation dose is lower.Additionally,the influence of the dose rate effects on threshold voltage is discussed.The research results show that the threshold voltage shift is more significant in low dose rate conditions,even for a low dose of100 krad(Si).The degeneration value of threshold voltage is 23.4%and 58.0%for the front-gate and the back-gate at the low dose rate,respectively.

STUDY ON THRESHOLD EFFECT OF Mg-DOPED LITHIUM NIOBATE CRYSTALS

This paper presents measurements of OH- absorption bands, fundamental optical absorption edge, lattice parameters, density, color center absorption spectra and Fe3+ ESR spectra at room temperature for a series of magnesium-doped and iron-doped lithium nio-bate crystals, and their dependence on magnesium concentration. It is observed that there exists the threshold effect of the magnesium dopant concentration in the measurements. The influence of the magnesium ion on the defect structure of magnesium-doped LiNbO3 crystal is studied by use of the defect chemistry. The formation of various defect lattices in the crystal at different magnesium dopant concentrations, their growth and decay rules are proposed. Calculations indicate that the defect lattice with Nb-site Mg2+ will be formed in a congruent LiNbO3 crystal when the MgO-doping level reaches 5.3%, which is taken as the main mark of the 'threshold'. The change caused by the 'threshold' in the ionic environment of the LiNbO3 crystal will serve to demonstrate the experimental results. And the calculation of the threshold concentration coincides with experiments. The conclusion in this paper can explain the reason for the drastic increase of anti-optical-damage capability in highly magnesium-doped LiNbO3. This is significant for the research on the modification of other ABO,-type electro-optic crystals.

An Improved SOI CMOS Technology Based Circuit Technique for Effective Reduction of Standby Subthreshold Leakage

Silicon-on-insulator (SOI) CMOS technology is a very attractive option for implementing digital integrated circuits for low power applications. This paper presents migration of standby subthreshold leakage control technique from a bulk CMOS to SOI CMOS technology. An improved SOI CMOS technology based circuit technique for effective reduction of standby subthreshold leakage power dissipation is proposed in this paper. The proposed technique is validated through design and simulation of a one-bit full adder circuit at a temperature of 27℃, supply voltage, VDD of 0.90 V in 120 nm SOI CMOS technology. Existing standby subthreshold leakage control techniques in CMOS bulk technology are compared with the proposed technique in SOI CMOS technology. Both the proposed and existing techniques are also implemented in SOI CMOS technology and compared. Reduction in standby subthreshold leakage power dissipation by reduction factors of 54x and 45x foraone-bit full adder circuit was achieved using our proposed SOI CMOS technology based circuit technique in comparison with existing techniques such as MTCMOS technique and SCCMOS technique respectively in CMOS bulk technology. Dynamic power dissipation was also reduced significantly by using this proposed SOI CMOS technology based circuit technique. Standby subthreshold leakage power dissipation and dynamic power dissipation were also reduced significantly using the proposed circuit technique in comparison with other existing techniques, when all circuit techniques were implemented in SOI CMOS technology. All simulations were performed using Microwindver 3.1 EDA tool.

Developmental Threshold Temperature and Effective Accumulated Temperature of Potosia brevitarsis Lewis

[ Objective] The paper was to study the relationship between temperature and development of Potosia brevitarsis Lewis. [ Methods] Six constant tem- peratures （21, 24, 27, 30, 33 and 36 ℃ ） were set in the laboratory to study developmental threshold temperature and effective accumulated temperature of P. brevitarsis. [ Result] The developmental durations of various states of P. brevitarsis were shortened with the increasing temperature ranged from 21 ℃ to 36 ℃ ; the developmental rates were accelerated with the increasing temperature. The developmental threshold temperatures of egg, larva, pupa and pre-ovipesition of adult were estimated to be 12.79, 9.15, 14.86 and 13.80 ℃, respectively; the effective accumulated temperature were 136.25, 3 031.31,308.92 and 98.35 d · ℃, respectively. The developmental threshold temperature and effective amcumulated temperature for one complete generation were 9.96 ℃ and 3 628.73 d · ℃, re- spectively. Combined with meteorological data, the theoretical generation number of P. brevitarsis occurred in Shihezi was presumed to be one per year, which was basically coincided with actual occurrence generations in fields. [ Conclusion] The paper provided theoretical basis for effective control against P. brevitarsis.

数字化转型对制造业企业创新效率的门槛效应研究

数字化转型可以突破研发资源配置时空边界,赋能制造业企业创新发展,但潜在的数字鸿沟问题也可能会加剧企业创新的不确定性。鉴于此,利用文本挖掘技术构造数字化转型指数,系统考察数字化转型对制造业企业创新效率的影响效应及作用机制,并选取2007—2022年中国A股制造业上市公司的微观数据进行实证分析。研究发现:数字化转型对制造业企业创新效率具有显著的门槛效应;对于大多数制造业企业来说,其数字化转型水平低于门槛值,数字化转型是提升制造业企业创新效率的助力,而非阻力;人力资本和公司治理是数字化转型影响制造业企业创新效率的传导路径。进一步研究发现,数字化转型对创新效率的门槛效应在国有企业和资本技术密集型制造业企业中更明显。研究结论为合理评估中国制造业推进数字化转型战略的实施效果提供了新视角,对国家充分发挥数字化转型战略与创新驱动发展战略的合力效应也具有政策启示意义。

数字乡村建设赋能农业经济韧性的影响机制及效应

数字经济为我国农业高质量发展带来新的机遇与挑战,探寻数字乡村建设对农业经济韧性的影响,可为我国推动农业农村现代化发展和建设农业强国提供理论与实证支撑。文章基于2011—2021年中国30个省份的面板数据,采用双向固定效应模型与面板门槛模型实证分析数字乡村建设对农业经济韧性的影响机制。研究发现:数字乡村建设通过促进产业结构升级显著提升了农业经济韧性;数字乡村建设赋能农业经济韧性的效果具有区域异质性,在西部地区的正向效应更显著;数字乡村建设赋能农业经济韧性的效果具有门槛效应,并且其赋能效果呈递减趋势。

物联网发展、科技创新与农业碳排放强度

农业生产导致的温室气体排放以及引发的环境问题,已成为人们关注的热点,研究物联网发展对农业碳排放强度的作用机理,有助于农业农村能源转型和促进农业绿色可持续发展。基于2010—2021年我国除港、澳、台外的31个省级地区的面板数据,分析物联网发展对农业碳排放强度的影响,以及科技创新在此过程中的作用。研究发现:物联网发展显著抑制了农业碳排放强度,并且存在显著异质性,在中国东部和中部地区,科技创新水平有效提升了物联网发展对农业碳排放强度的抑制作用。把农业科技创新水平作为门槛变量,发现物联网发展和农业碳排放强度之间存在非线性关系,当农业科技创新水平跨越门槛值后,物联网发展对农业碳排放强度的抑制作用显著增强。研究结论在推动数字化农业、促进科技与农业融合方面具有理论和实践价值。

流通业集聚对农业韧性的影响

提升农业韧性是加快推进农业强国的重要内容。面对资源环境约束、人口红利衰减等诸多问题,深入分析流通业集聚对农业韧性的影响,有助于提升供应链效率,推进农业供给侧结构性改革,夯实国家粮食安全根基。以2008—2020年省级面板数据为样本,通过熵值法和区位熵测算农业韧性和流通业集聚程度,采用空间杜宾模型和门槛效应模型进行实证分析。研究发现,流通业集聚与农业韧性存在显著空间关联性,且具有空间集聚特征。流通业集聚对农业韧性存在空间溢出效应。在溢出效应下,流通业集聚不仅对本地区农业韧性存在促进作用,对周边地区也存在积极影响。受到流通业集聚程度影响,流通业集聚对农业韧性的影响在东部地区比较明显,中部地区次之,在西部地区不明显。流通业集聚对农业韧性的影响存在门槛效应,当流通业集聚程度低于门槛值0.803时,存在促进作用;当越过门槛值0.803时,促进作用显著提升。基于此,要进一步发挥流通业集聚效应,加快建设高效的农村现代流通体系,同时要促进地区间合作交流,加强农产品流通枢纽建设,继续为农业发展蓄势赋能。