新疆棉农连作行为分析 —基于棉花替代作物可选择空间的思考

40多年来,新疆农业结构的调整的是从以小麦为主导地位的作物结构向棉花占主导地位的作物结构的转变过程。但是在植棉比重越来越高的过程中,棉花连作现象也日渐突出,该文通过相关数据资料说明了连作的危害,并从棉花的替代作物可选择性空间角度分析了棉农连作行为。     

从扩大开放到制度型开放：对外开放平台的演进与升级

在“进口替代—出口导向—高水平对外开放”的战略转换中，改革开放后我国对外开放平台建设经历了“局部开放—全面开放—制度型开放”三个阶段，在政策和时间维度上从扩大开放向制度型开放演进，在空间格局上从东部率先开放向东西协同开放进化，在主要功能上从单一（如出口加工区）向复合（如自由贸易试验区）拓展。对外开放平台的建设历程反映了我国国际分工地位的转变和开放制度的演化，不仅形成了从沿海到内陆全方位、多领域、深层次的对外开放格局，还推动塑造了不同阶段国内区域经济发展的空间格局。中国的制度型开放不同于以美国为代表的国内制度国际化模式和以日韩为代表的对接国际经贸规则模式，具有突出的包容性特征。应以中国特色制度型开放推进对外开放平台建设转型升级：积极开展先行先试，构建高水平的制度型对外开放平台体系；推动多区叠加和东西合作，促进对外开放平台红利溢出；深化对外开放平台的跨境合作，维护多元稳定的国际经贸关系；加快制度创新成果的复制推广，强化对外开放平台以点带面的功能和优势。     

Increasing Wages,Factor Substitution,and Cropping Pattern Changes in China

This article analyzed the influence of increasing wages on cropping patterns from theoretical and empirical perspectives. The results showed that the increasing labor cost provided a significant incentive to adjust the grain cropping pattern, which increased the production of the three major cereal grains but reduced the production of other grain crops. Increasing wages had a significant negative impact on cash crops. More labor-intensive cash crops experienced a larger negative impact in the context of increasing wages. The increase in labor costs also had a negative impact on the proportion of vegetables produced, which was more evident in northern China. A further mechanism test indicated that factor substitution was a significant reason for cropping pattern changes; this illustrated the substitution of labor by machinery not only between grain crops and cash crops but also among different cash crops.     

互联网发展与区域经济收敛——基于空间计量的分析

互联网具有“时空压缩”特质和新经济增长点“催化剂”效应,逐渐成为欠发达地区实现跨越式发展的驱动力量。本文以中国30个省(区、市)2006~2019年的面板数据为样本构建互联网发展指标体系,基于空间条件收敛模型,分析互联网发展对区域经济收敛的影响。结果表明:互联网发展对中国区域经济收敛具有促进作用,且呈现直接和溢出的双重促进效应;异质性研究发现互联网发展对东、西部区域经济收敛具有促进作用,但对中部地区影响不显著。本文研究一定程度上解释了互联网发展对区域差距稳态趋同的作用,对实现我国区域协调发展具有重要的现实意义。     

Piecewise linear double barrier options

A piecewise linear double barrier option generalizes classical double barrier options because of its versatility in designing various double boundaries. This paper discusses how to price piecewise linear double barrier options. To this purpose, we derive the probability that an underlying process does not cross a given piecewise linear double barrier, where the underlying process follows the Brownian motion of piecewise constant drift. Using the established non-crossing probability, we provide the explicit pricing formulas of piecewise linear double barrier options and show how the shape of a double barrier affects the option prices through extensive numerical experiments.     

产业转移能促进地区产业结构优化升级吗？——基于承接产业转移示范区的事实检验

利用275个地级市2004—2018年的数据通过双重差分法分析国家级承接产业转移示范区对所在地产业结构的影响。结果表明：示范区的成立会对所在地的产业结构高级化和产业结构合理化产生显著的抑制作用；在一段时间后，示范区对产业结构合理化的影响会由负效应转变为正效应，对产业结构高级化的负面影响也会变得不再显著；示范区位于不同地区、高新区、政府规模都会使示范区对地区产业结构产生不同的影响。据此提出对示范区建设的几点建议。     

How convergent are rice export prices in the international market?

This study revisits the issue of long-term price convergence of rice export prices for India, Pakistan, Thailand, Uruguay, the United States, and Vietnam using a two-stage pairwise unit root testing approach. To deduce evidence or lack of proof of convergence in price series, we also examine convergence using sigma and beta convergence specified in both unconditional and conditional frameworks. The methodology used is driven by the need to address three key concerns: (i) the likelihood of finding stationary price differentials, (ii) the magnitude of these differentials, and (iii) their speed of adjustment. To evaluate these concerns, we use monthly data for 18 price series drawn from these six countries from September 2011 to February 2021. The evidence points to a lack of international convergence. This gives rise to the possibility that a shield from a general downward export price trend is already in place for some exporters. Furthermore, we find that the likelihood of convergence is greater between pairs of price series that are characterized as high quality or having the same country of origin or having similar market share. Evidence also suggests that a converged pairing is more likely to have a smaller price differential if both price series are for low-quality rice.     

Climate-resilient practices and welfare impacts on rice-cultivating households in Vietnam: Does joint adoption of multiple practices matter?

Farmers have a long history of adjusting their production practices in response to changing production conditions. Using a multinomial endogenous treatment effects model that accounts for observable and unobservable heterogeneity, this study investigates the adoption and welfare impacts of climate-resilient practices on Vietnamese rice-cultivating households. We found evidence of clear and positive welfare impacts from the adoption of canal irrigation (CI) and the joint adoption of agricultural conservation practices (CP) and CI as the main adaptation strategies to increase water stress. More importantly, although farmers with access to CI systems obtained the highest returns, the joint adoption of multiple practices still had substantially high adoption rates and significantly positive effects on rice yield, rice revenue and household income. Our findings indicate that farms' and farmers' characteristics, market information and climatic conditions are generally the main factors driving rice farmers' decisions to adopt climate-resilient technologies, both individually and jointly. Follow-up policy interventions should focus on improving CI systems and promoting the joint adoption of climate-resilient technologies to improve rice farmers' well-being and enhance their resilience capacity to cope with incoming climatic uncertainty.     

限购政策对房地产开发贷款风险的影响研究

基于2007-2019年全国50个大中城市的面板数据,运用多时点双重差分模型,分析限购政策对房地产开发贷款风险的影响。研究表明:限购政策会显著降低房地产开发贷款风险,但该抑制作用的持续时间较短,不具有长期持续的显著效果;采用平行趋势检验等稳健性检验后,结论仍然稳健;相较于非一线城市和中西部地区,限购政策对一线城市和东部地区房地产开发贷款风险的抑制作用更为显著。根据理论机制和实证结论,本文从坚持“房住不炒”战略方针、因城施策实行差异化限购政策、健全房地产开发贷款风险防控长效机制三个方面提出促进房地产市场健康运行的对策建议。     

碳交易试点政策对中国区域经济绿色增长的影响机制研究

碳排放权交易既是实现“双碳”目标的必然选择，也是推动中国区域经济绿色增长的重要途径。本文基于“波特假说”和新发展理念，探讨碳交易试点政策对中国区域经济绿色增长的影响机制。将试点政策作为一项准自然实验，基于2005—2018年中国内地30个省份面板数据（因数据缺失，不包括西藏和港澳台地区），采用双重差分模型进行实证检验。结果表明：(1)碳交易试点政策对中国区域经济绿色增长起显著促进作用，且存在正向累积动态效应，经过安慰剂检验和PSM-DID检验，发现结论依然成立。(2)碳交易试点政策对中国区域经济绿色增长的影响具有区域异质性，东部地区政策促进效应显著，而中部地区不显著，西部地区则呈现不明显的抑制效应。(3)机制研究表明，碳交易试点政策通过推动绿色技术创新、调整产业结构、优化能源结构、吸引外商直接投资以及促进共享发展以实现中国区域经济绿色增长。其中，共享发展的中介效应最大，其次为绿色技术创新和产业结构，而能源结构和外商直接投资的中介效应较小。(4)分区域机制检验发现，东部地区共享发展的中介效应最大，绿色技术创新和产业结构次之，能源结构的中介效应最小；中部地区中介效应最大为能源结构，其次为绿...