Can a polycentric structure affect travel behaviour?A comparison of Melbourne, Australia and Riyadh, Saudi Arabia

This study models the impact of the shift from a monocentric private-car-oriented city to polycentric public-transport-oriented city. Metropolitan areas have suffered traffic problems in particular increase in travel time and travel distance. Urban expansion, population growth and road network development have led to urban sprawl in monocentric cities. In many monocentric cities, travel time and distance has steadily increased and is only expected to increase in the future. Excessive travel leads to several problems such as air pollution, noise, congestion, reduction in productive time, greenhouse emissions, and increased stress and accident rates. This study examines the interaction of land use and travel. A model was developed and calibrated to Melbourne and Riyadh conditions and used for scenario analysis. This model included two parts： a spatial model and a transport model. The scenario analysis included variations of residential and activity distribution, as well as conditions of public transport service.

Differentiated effects of morphological and functional polycentricurban spatial structure on carbon emissions in China: an empiricalanalysis from remotely sensed nighttime light approach

Understanding the relationship between urban development and environmental sustainability to achieve‘double carbon’goals in China can be strengthened by evaluating the environmental effect of urban spatial structure(US).However,there have been few studies that consider the differentiated effects of polycentric US(PUS)on carbon emissions from both functional and morphological perspectives simultaneously.Thus,taking China’s 31 provinces as experimental subjects,our study developed a novel framework with remotely sensed nighttime light(NTL)data to quantify morphological PUS(MPUS)and functional PUS(FPUS)from 2000 to 2019.Then,from these two dimensions,differentiated effects of PUS on carbon emissions were further examined.Results indicated that NTL data presented high potential in quantifying MPUS and FPUS.The effect of FPUS on carbon emission-cutting outperformed that of MPUS.In addition,the spillover effect effectively enhanced the decreasing effect of the FPUS on carbon emissions.Our empiricalfindings can provide guidance for the government in developing strategies for reducing carbon emissions and optimizing USs.

Multiscale Characteristics and Connection Mechanisms of Attraction Networks:A Trajectory Data Mining Approach Leveraging Geotagged Data

Urban tourism is considered a complex system,and multiscale exploration of the organizational patterns of attraction networks has become a topical issue in urban tourism,so exploring the multiscale characteristics and connection mechanisms of attraction networks is important for understanding the linkages between attractions and even the future destination planning.This paper uses geotagging data to compare the links between attractions in Beijing,China during four different periods:the pre-Olympic period(2004–2007),the Olympic Games and subsequent‘heat period’(2008–2013),the post-Olympic period(2014–2019),and the COVID-19(Corona Virus Disease 2019)pandemic period(2020–2021).The aim is to better understand the evolution and patterns of attraction networks at different scales in Beijing and to provide insights for tourism planning in the destination.The results show that the macro,meso-,and microscales network characteristics of attraction networks have inherent logical relationships that can explain the commonalities and differences in the development process of tourism networks.The macroscale attraction network degree Matthew effect is significant in the four different periods and exhibits a morphological monocentric structure,suggesting that new entrants are more likely to be associated with attractions that already have high value.The mesoscale links attractions according to the common purpose of tourists,and the results of the community segmentation of the attraction networks in the four different periods suggest that the functional polycentric structure describes their clustering effect,and the weak links between clusters result from attractions bound by incomplete information and distance,and the functional polycentric structure with a generally more efficient network of clusters.The pattern structure at the microscale reveals the topological transformation relationship of the regional collaboration pattern,and the attraction network structure in the four different periods has a very similar importance profile structure suggesting that the attraction network has the same construction rules and evolution mechanism,which aids in understanding the attraction network pattern at both macro and micro scales.Important approaches and practical implications for planners and managers are presented.

Will polycentric cities cause more CO2 emissions? A case study of 232 Chinese cities

From 2000 to 2010 China experienced rapid economic development and urbanization.Many cities in economically developed areas have developed from a single-center status to polycentricity.In this study,we used exploratory spatial data analysis (ESDA) to identify the population centers,which identified 232 cities in China as having urban centers.COMP was used to represent urban agglomeration,and POLYD (representing how far is the city’s sub-centers to the main center),POLYC (representing the number of a city’s centers),and POLYP (representing the population distributed between the main center and the sub-centers) were used to indicate urban polycentricity.Night light data were used to determine the CO2 emissions from various cities in China.A mixed model was used to study the impact of urban aggregation and polycentric data on the CO2 emission efficiency in 2000 and 2010.The study found that cities with higher compactness were distributed in coastal areas,and the cities with higher multicentricity were distributed in the Yangtze River Delta and Shandong Province.The more compact the city was,the less conducive it was to improving CO2 emission efficiency.Polycentric development of the city was conducive to improving the CO2 emission efficiency,but the number of urban centers had no significant relationship with the CO2 emission efficiency.Our research showed that the compactness and multicentricity of the city had an impact on the CO2 emission efficiency and provided some planning suggestions for the low carbon development of the city.

Research on the carbon neutrality governance under a polycentric approach

Carbon neutrality has increasingly become a crucial agenda within global climate governance.Meanwhile,recent observations show that the governance architecture for carbon neutrality is transforming to polycentricity.However,there is still a lack of systematic investigation on carbon neutrality governance under the polycentric approach.Against this background,this study attempts to investigate the emergence and structure of polycentric climate governance,and to figure out to what extent the evolving polycentric system can contribute to the climate change governance towards carbon neutrality.The results show that efforts made by actors at transnational and subnational levels within the polycentric system can greatly complement the deficits of carbon neutrality governance by international regime and state government in many different domains.Besides,the identified issues,that are critical to carbon neutrality including climate legislation,adaptation,technology deployment and data authenticity and transparency,can be addressed in a more effective way through the coordination among multiple actors at multiple levels.Finally,further research should be conducted to address the dynamic linkages between international regimes as well as the issues related to small and medium-sized cities,and develop a comprehensive evaluation and accounting system for the risks and benefits of polycentric climate governance.

Relationship between different surgical methods,hemorrhage position,hemorrhage volume,surgical timing,and treatment outcome of hypertensive intracerebral hemorrhage

BACKGROUND:The present study aimed to explore the relationship between surgical methods,hemorrhage position,hemorrhage volume,surgical timing and treatment outcome of hypertensive intracerebral hemorrhage(HICH).METHODS:A total of 1 310 patients,who had been admitted to six hospitals from January 2004 to January 2008,were divided into six groups according to different surgical methods:craniotomy through bone fl ap(group A),craniotomy through a small bone window(group B),stereotactic drilling drainage(group C1 and group C2),neuron-endoscopy operation(group D) and external ventricular drainage(group E) in consideration of hemorrhage position,hemorrhage volume and clinical practice. A retrospective analysis was made of surgical timing and curative effect of the surgical methods.RESULTS:The effectiveness rate of the methods was 74.12% for 1 310 patients after onemonth follow-up. In this series,the disability rate was 44.82% 3–6 months after the operation. Among the 1 310 patients,241(18.40%) patients died after the operation. If hematoma volume was >80 mL and the operation was performed within 3 hours,the mortality rate of group A was signifi cantly lower than that of groups B,C,D,and E(P<0.05). If hematoma volume was 50–80 mL and the operation was performed within 6–12 hours,the mortality rate of groups B and D was lower than that of groups A,C and E(P<0.05). If hematoma volume was 20–50 mL and the operation was performed within 6–24 hours,the mortality rate of group C was lower than that of groups A,B and D(P<0.05).CONCLUSIONS:Craniotomy through a bone f lap is suitable for patients with a large hematoma and hernia of the brain. Stereotactic drilling drainage is suggested for patients with hematoma volume less than 80 mL. The curative effect of HICH individualized treatment would be improved via the suitable selection of operation time and surgical method according to the position and volume of hemorrhage.

国家行政区划调整下的城市多中心发展——城市空间转型的政策启示

Polycentric urban development has profound impacts on urban development worldwide.Most studies have identified its complex drivers of social economy and natural condition while ignoring the state-led policy factors.In recent years,China has undergone dramatic administrative division adjustment(ADA)during the process of unique state-led urbanization.However,as a crucial government strategy,the impacts of ADA on urban polycentricity remain unclear.This research investigates the relationship between ADA and urban polycentricity through spatial difference-in-differences models.The results reveal that ADA has contributed to the polycentric urban development in China.Specifically,boundary restructuring has more substantial impacts than hierarchy reorganization.In addition,ADA has significantly promoted urban polycentricity in local cities in central China and neighbouring cities in eastern China,while it has no significant effects in western China.Furthermore,ADA reshapes urban polycentricity mainly by the influencing mechanism of construction land and industrial structure.Policymakers should consider the various ADA’s impacts on urban polycentricity with socio-economic conditions.This research provides a deeper insight into urban spatial transformation with state-led drivers.

繁复现实下的简约制度:一个新分析框架

本文探讨了人口、技术与组织这三方面因素给当代社会经济活动带来的巨大变化,分析了20世纪以市场制度和公司制度为核心的主流经济制度的局限性,阐述了经济分化格局以及充满复杂性和多样性的现实世界给主流经济制度带来的艰巨挑战。本文认为,进入21世纪,经济制度分析需要向三个方向推进转变:一是转向跨层次思维;二是转向适应多重制度逻辑支配的混合组织;三是转向多中心主义与多中心治理体制。

基于公路客流的中国城市网络结构与空间组织模式（英文）

The use of multi-perspective and multi-scalar city networks has gradually developed into a range of critical approaches to understand spatial interactions and linkages. In particular, road linkages represent key characteristics of spatial dependence and distance decay, and are of great significance in depicting spatial relationships at the regional scale. Therefore, based on highway passenger flow data between prefecture-level administrative units, this paper attempted to identify the functional structures and regional impacts of city networks in China, and to further explore the spatial organization patterns of the existing functional regions, aiming to deepen our understanding of city network structures and to provide new cognitive perspectives for ongoing research. The research results lead to four key conclusions. First, city networks that are based on highway flows exhibit strong spatial dependence and hierarchical characteristics, to a large extent spatially coupled with the distributions of major megaregions in China. These phenomena are a reflection of spatial relationships at regional scales as well as core-periphery structure. Second, 19 communities that belong to an important type of spatial configuration are identified through community detection algorithm, and we suggest they are correspondingly urban economic regions within urban China. Their spatial metaphors include the administrative region economy, spatial spillover effects of megaregions, and core-periphery structure. Third, each community possesses a specific city network system and exhibits strong spatial dependence and various spatial organization patterns. Regional patterns have emerged as the result of multi-level, dynamic, and networked characteristics. Fourth, adopting a morphology-based perspective, the regional city network systems can be basically divided into monocentric, dual-nuclei, polycentric, and low-level equilibration spatial structures, while most are developing monocentrically.

世界基督教历史的多中心结构

作为世界宗教的基督教和作为学科的教会史基督教是世界性宗教,但作为学科的教会史却停滞不前。在德语学术界内,基督教新教神学系研究教会史始终注目在古代地理范围内。1900年代,全球基督徒中大约有82%生活在北半球,而1980年以来,基督徒中的大多数则生活在所谓的'全球南方'即亚非拉美第三世界国家。2007年,约65%的基督徒生活在第三世界国家,而且还在增长。因而,从全球来看,基督徒并没有在萎缩,像我们在世俗化的欧洲正普遍经历着的人口重心和增长区域已转移至南半球,普世运动讨论中以'重心转移'来命名。教会史学科对其中有些戏剧性的变化有所选择地回应过,身为教会史学者。

哈尔滨多中心空间结构交通绩效检验——基于区位再选择假设的分析

In recent years,with the increasingly serious traffic problems in large cities of China,transformation to polycentric urban spatial structure has been considered as an important initiative to improve the urban traffic performance.This study examines the traffic performance of the polycentric spatial structure of Harbin,and analyzes the factors influencing the traffic performance of the structure using the location reselection hypothesis theory.The results show that the polycentric spatial structure does not significantly improve Harbin’s traffic performance,and only the centers in peripheral areas indicate advantages in commuting speed and distance,to which the main reason is that the social and spatial factors reduce the importance of commuting costs,making long-distance commuting economically rational and hindering possible location reselection.It is an effective direction for the improvement of the traffic performance of polycentric spatial structure by facing up to the rationality of long-distance commuting and transportation demand,improving the location equilibrium of residential and employment resources,and constructing high-grade centers in peripheral areas in appropriate locations and with comprehensive functions.