撤县设区与区域经济发展——基于双重差分方法的政策评估

撤县设区作为行政区划调整的一项政策措施,对于缓解土地资源紧张、推动城市化进程、加快经济一体化方面具有重要意义,但其对区域经济发展的多维影响及其机制还有待进一步验证。以广东省为研究区域,利用79个县（市）2000—2015年的面板数据,运用双重差分方法系统考察撤县设区对区域经济发展的“净”影响。结果表明：撤县设区显著促进了区域经济发展,平均而言,撤县设区对经济发展的贡献为4.8%;撤县设区在珠三角地区效果更好,而在非珠三角地区不稳定;撤县设区的政策红利具有时间滞后性,一般在第三、第四年才开始显现;此外,机制分析发现,撤县设区后能够获得基建、规划、政策等的有力支持,增加财政收入和固定资产投资,有助于第二产业及其相关产业发展,并在增加就业和刺激消费基础上着力推动经济发展。     

Revisiting the Relationship Between Urbanization and Economic Development in China Since the Reform and Opening-up

The relationship between urbanization and economic development has become a hot topic in the scientific community due to its great practical significance,and economic and social value.However,this relationship continues to change dynamically.In the new stage of urbanization,it is urgent to reveal the causal relationship quantitatively and diagnose the future direction systematically.Based on this,this paper calculates the contribution rate of China’s urbanization to economic development from 1978 to 2019 and uses the panel data cointegration test method to explore the causal relationship between urbanization and economic development in China.The study has three principal results.First,the contribution rate of urbanization to economic growth has maintained the overall growth trend from1978 to 2019,but the growth rate of urbanization’s contribution to economic growth has been relatively low since 2012.It is an important reason that the real estate sector has moved into a new stage of transformation.Second,the cointegration test shows that economic development is a significant factor in advancing urbanization and the urbanization is the product of economic development.Urbanization has a positive feedback effect on economic development,but this effect does not pass the 5%significance level test.The impulse response function shows that the impact of urbanization on economic development is relatively small and stable,indicating that it is limited that the boost of economic development by land-centered urbanization.Third,China’s urbanization and economic development have both shown rapid growth for some time,but their relationship is still the low level of coordination,which has also led to a downward trend in the contribution of new-type,people-oriented urbanization to economic growth in recent years.In the future,China’s urbanization and economy need to maintain relatively medium-low speed growth in the medium-long term,and we should boost the coordinated development of urbanization and economy from low level to high level.     

Identifying the scope of the Lhasa Metropolitan Area based on a spatial field energy model

The cultivation and development of modern metropolitan areas with the aim of establishing new regional centers with competitive edge is a key objective for the new-type urbanization directions in China. The construction of the Lhasa Metropolitan Area is of great significance for the promotion of the South Asia Channel, the ‘Belt and Road' initiative, the Bangladesh-China-India-Myanmar Economic Corridor, the Himalaya Economic Cooperation Zone, and for rapid development and long-term stability of the Qinghai-Tibet Plateau. This paper examines the scope of the Lhasa Metropolitan Area including Chengguanqu(Chengguan District), Doilungdeqen, Dagze, Lhunzhub, Damxung, Nyemo, Quxu, Maizhokunggar, Samzhubze Qu(Samzhubze District), Gyangze, Rinbung, Bainang, Nedong, Gonggar, and Zhanang using a spatial field energy model that combines nodality and accessibility indices and considers multiple indicators including traffic flow between cities. By combining factors such as the natural background, population agglomeration, the social economy, infrastructure construction, and the urban spatial structure of the Lhasa Metropolitan Area, it is proposed to build a bow-and-arrow-shaped urban system with ‘one core, two centers, one axis, and two wings' along the valleys and the transportation trunk lines of the area. The study advocates the construction of a pure land industrial system comprising a green cultural and tourism-oriented plateau.     

Quantitative simulation and verification of upgrade law of sustainable development in Beijing-Tianjin-Hebei urban agglomeration

The natural formation and development of urban agglomerations is a process in which core cities continue to unite their neighboring cities to enhance sustainability for their own sustainable development.The upgrade mechanism of sustainable development urban agglomeration is a nonlinear composite upgrade curve that is a function of time,increasing with the number of cities.In this paper,the sustainable upgrade function curve,upgrade rate,and upgrade speed of urban agglomerations were solved using a geometrical derivation,and the index system for measuring the upgrade capability of sustainable development of urban agglomerations was established.The dynamic change in economic sustainable upgrade capability,social sustainable upgrade capability,environmental sustainable upgrade capability,and comprehensive sustainable upgrade capability of a Beijing-Tianjin-Hebei urban agglomeration from 2000 to 2015 was measured by technique for order preference by similarity to an ideal solution and a grey correlation method,and a comprehensive,intercity unite strength model and a unite threshold calculation method for urban agglomerations were established.The research shows that the economic sustainable upgrade capability,social sustainable upgrade capability,environmental sustainable upgrade capability,and comprehensive sustainable upgrade capability of the Beijing-Tianjin-Hebei urban agglomeration all show a wave-like rising trend.The average annual upgrade speeds during 2000-2015 are,respectively,2.4%.1.67%,1.1%,and 1.74%,with the intercity comprehensive unite strength of urban agglomerations maintaining a general increase;but there is a limit to the joint threshold.From 2000 to 2015,as the core city of the Beijing-Tianjin-Hebei urban agglomeration,Beijing,to enhance its sustainable upgrade capability,jointly developed with Tianjin,Langfang,and Baoding before 2000,Tangshan in 2002,Cangzhou in 2009,Zhangjiakou and Shijiazhuang in 2012,and Chengde in 2014.By 2015,the comprehensive unite strength between Beijing and four cities(Handan,Qinhuangdao,Hengshui,and Xingtai) was still lower than the unite threshold of 6.14.These four cities are relatively far from Beijing,and offer no substantial contribution to the sustainable upgrade capability of Beijing.Through multiple fittings of the upgrade curve using the long-term sequence index of the comprehensive sustainable upgrade capability of Beijing(the core city of the Beijing-Tianjin-Hebei urban agglomeration) from 2000 to 2015,it was found that the simulated curve of the comprehensive sustainable upgrade function of the agglomeration was very similar to the curve of the comprehensive sustainable upgrade capability,which indicates that the simulation results are satisfactory.The future comprehensive sustainable upgrade capability of the agglomeration can be analyzed and predicted by the comprehensive sustainable upgrade function model.This study provides quantitative decision-supporting evidence for promoting the coordinated development of the Beijing-TianjinHebei urban agglomeration and provides theoretical guidance and algorithms for determining the number of cities joined with the sustainable development of national urban agglomerations.     

美丽中国与国土空间规划关系的地理学思考

美丽中国是社会主义新时代生态文明建设的新目标愿景,满足人民群众对美好生活向往的现实需求。国土空间规划是国家统筹涉及空间各类规划的重大部署。美丽中国是国家第二个一百年发展新的引领目标,其内涵不仅是“生态美丽”,也是“经济—政治—文化—社会—生态”综合的大美丽,美丽中国建设要因地制宜构建差异化的评估指标体系。美丽中国和国土空间规划有着密切联系,美丽中国为国土空间规划指引了重要方向,国土空间规划则为美丽中国建设提供了重要途径和空间保障。国土空间规划编制需要加强人地关系地域系统、点—轴系统、主体功能区划、可持续发展与资源环境承载力、新型城镇化、乡村地域多体系统等深入探讨。本文提出了地理学视角下国土空间规划编制的思路框架,科学分析国土空间的自然地理条件、经济社会发展基础、国土空间相互联系,结合美丽中国目标,谋划国土空间的目标、愿景与路径,鼓励公众参与与开展动态评估,构建智能系统平台等,为国土空间规划编制实施提供思路借鉴。     

喀斯特湿地水葫芦(Eichhornia crassipes)生长及表型可塑性特征对不同富营养化水体的响应

选择桂林会仙喀斯特湿地,以不同富营养化水体中生长时期为6月(生长旺盛期)和8月(暴发高峰期)的水葫芦(Eichhornia crassipes)为研究对象,探讨不同富营养化条件下水葫芦的生长及表型可塑性响应特征,以揭示水葫芦对不同富营养化水体的生态适应机制.结果表明:水葫芦的株高、根长和叶绿素含量均随水体富营养化程度的增加而降低,叶柄数、叶柄宽、叶片数、叶长、叶宽、匍匐茎数和分株速率随着水体富营养化程度的增加而升高;各性状参数在暴发高峰期均略高于生长旺盛期;根生物量、茎生物量、叶生物量和总生物量均随水体富营养化程度的加深而增加,茎生物量高于根生物量和叶生物量;水葫芦生物量的分配以及性状间的权衡关系(根生物量比、茎生物量比、叶生物量比和茎叶比等)因生长时期的不同而呈现差异性,表现出较强的表型可塑性特征;水体总有机碳、总氮、总磷、硝态氮、氨氮和叶绿素a浓度分别与水葫芦的茎生物量、叶宽、匍匐茎数和分株速率间存在显著的正相关关系,与根长、株高、叶生物量比和茎叶比间存在显著的负相关关系;水葫芦的表型可塑性指数在0.009~0.792之间,叶重比的可塑性指数最大,根冠比最小,重度富营养化水体下的可塑性指数最大.在会仙喀斯特湿地不同富营养化水体环境中,水葫芦通过外部形态结构调节和生物量的配比关系,产生了有利于其入侵和存活的较强的表型可塑性,是其生存繁殖的重要响应机制之一.     

Soil properties as indicators of desertification in an alpine meadow ecosystem of the Qinghai–Tibet Plateau, China

The objective of this study was to examine the variation of time and space and the effects of alpine meadow desertification, and the study area was selected at the Qinghai–Tibet Plateau of China. The sampling locations were categorized as the top, middle, bottom of the slope and flat in front of the slope, and the sites were classified as alpine meadow, light desertified land, moderate desertified land, serious desertified land, and very serious desertified land according to the level of alpine meadow desertification. This study examined spatial and temporal variability in soil organic carbon (SOC), total nitrogen (TN), pH, and soil bulk density due to wind erosion and documents the relationship between soil properties and desertification of alpine meadows. Desertification caused decreases to soil organic carbon and total nitrogen and increases to pH and soil bulk density. Soil properties were greatly affected by the level of alpine meadow desertification with the changes being attributed to overgrazing. The middle portion of slopes was identified as being the most susceptible to desertification. Carbon and nitrogen stocks were found to decrease as desertification progressed, the SOC stocks were 274.70, 273.81, 285.26, 196.20, and 144.36 g m^?2 in the alpine meadow, light desertified land, moderate desertified land, serious desertified land and very serious desertified land, respectively; and the TN stocks were 27.23, 27.11, 28.35, 20.97, and 17.09 g m^?2 at the top 30 cm soil layer, respectively. To alleviate desertification of alpine meadow, conservative grazing practices should be implemented.     

电力工程项目管控系统之信息化——领导查询需求设计和实施

做领导查询需求难,领导也讲不清;领导查什么？表格和图表。这是本文要介绍的主要原因及内容,本人通过公司信息化建设近十年的经验,一般员工到领导的信息需求都经历过,对过程体会较深。通过下面内容的简单扼要介绍为领导查询的设计提供一些意见。     

Spatiotemporal evolution of PM2.5 concentrations in urban agglomerations of China

As the main form of new urbanization in China,urban agglomerations are an im-portant platform to support national economic growth,promote coordinated regional devel-opment,and participate in international competition and cooperation.However,they have become core areas for air pollution.This study used PM2.5 data from NASA atmospheric re-mote sensing image inversion from 2000 to 2015 and spatial analysis including a spatial Durbin model to reveal the spatio-temporal evolution characteristics and main factors con-trolling PM2.5 in China's urban agglomerations.The main conclusions are as follows:(1)From 2000 to 2015,the PM2.5 concentrations of China's urban agglomerations showed a growing trend with some volatility.In 2007,there was an inflection point.The number of low-concentration cities decreased,while the number of high-concentration cities increased.(2)The concentrations of PM2.5 in urban agglomerations were high in the west and low in the east,with the"Hu Line"as the boundary.The spatial differences were significant and in-creasing.The concentration of PM2.5 grew faster in urban agglomerations in the eastern and northeastern regions.(3)The urban agglomeration of PM2.5 had significant spatial concentra-tions.The hot spots were concentrated to the east of the Hu Line,and the number of hot-spot cities continued to rise.The cold spots were concentrated to the west of the Hu Line,and the number of cold-spot cities continued to decline.(4)There was a significant spatial spillover effect of PM2.5 pollution among cities within urban agglomerations.The main factors control-ling PM2.5 pollution in different urban agglomerations had significant differences.Industriali-zation and energy consumption had a significant positive impact on PM2.5 pollution.Foreign direct investment had a significant negative impact on PM2.5 pollution in the southeast coastal and border urban agglomerations.Population density had a significant positive impact on PM2.5 pollution in a particular region,but this had the opposite effect in neighboring areas.Urbanization rate had a negative impact on PM2.5 pollution in national-level urban agglomer-ations,but this had the opposite effect in regional and local urban agglomerations.A high degree of industrial structure had a significant negative impact on PM2.5 pollution in a region,but this had an opposite effect in neighboring regions.Technical support level had a signifi-cant impact on PM2.5 pollution,but there were lag effects and rebound effects.     

Recently Ratified and Proposed Cambrian Global Standard Stratotype-section and Points

This paper briefly summarizes an officially ratified Global Standard Stratotype-section and Point (GSSP) and a proposed GSSP for global stages of the Cambrian System. The Luoyixi section near Luoyixi town, Guzhang, northwestern Hunan is ratified as the boundary stratotype for the base of the global Guzhangian Stage, which is the upmost stage of an unnamed series termed provisionally as Cambrian Series 3. The GSSP position lies 121.3 m above the base of the Huaqiao Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Lejopyge leavigata. The Duibian B section at Duibian village, Jiangshan, western Zhejiang, is proposed as the boundary stratotype for the base of the proposed global Jiangshanian Stage that is the second stage of the Furongian Series. The proposed GSSP position lies 108.12 m above the base of the Huayansi Formation in the section, coinciding with the first appearance of the cosmopolitan agnostoid trilobite Agnostotes orientalius. This horizon is also with the first appearance of the cosmopolitan polymerid trilobite Irvingella angustilimbata.