scholarly journals Assessment of spatio-temporal evolution of regionally ecological risks based on adaptive cycle theory: a case study of Yangtze River Delta urban agglomeration

2021 ◽  
Vol 41 (7) ◽  
Author(s):  
李嘉艺，孙璁，郑曦 LI Jiayi
Keyword(s):  
Yangtze River ◽  
Temporal Evolution ◽  
Yangtze River Delta ◽  
River Delta ◽  
Urban Agglomeration ◽  
Ecological Risks ◽  
Adaptive Cycle ◽  
Spatio Temporal

scholarly journals Spatio-temporal evolution and mechanism of regional innovation efficiency: Evidence from Yangtze River Delta Urban Agglomeration of China

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253598
Author(s):  
Xianzhong Cao ◽  
Bo Chen ◽  
Yuefang Si ◽  
Senlin Hu ◽  
Gang Zeng
Keyword(s):  
Yangtze River ◽  
Temporal Evolution ◽  
Returns To Scale ◽  
Yangtze River Delta ◽  
Spatial Inequality ◽  
River Delta ◽  
Urban Agglomeration ◽  
Regional Innovation ◽  
Spatio Temporal ◽  
Constant Returns To Scale

Regional innovation is an important research topic in economic geography, the spatio-temporal evolution and mechanism of regional innovation efficiency have recently become a hot for economic geographers. From the perspective of input and output efficiency, this paper constructs evaluation indicator of regional innovation, with the help of Constant Returns to Scale (CRS) and Variable Returns to Scale (VRS) models, and Malmquist indicator method of Data Envelopment Analysis (DEA), to analyze regional innovation performance, evolution trend, spatial differentiation, and evolution mechanism of Yangtze River Delta Urban Agglomeration (YRDUA) of China. The results show that: (i) Innovation efficiency of YRDUA is generally low, most of which is less than 80 percent of optimal efficiency; however, it kept rising from 2000 to 2015. (ii) Spatial inequality of regional innovation in YRDUA is significant, with a spatial pattern in the shape of “Z”, composed by Hefei, Nanjing, Shanghai, Hangzhou and Ningbo, innovation efficiency of Shanghai is higher than Zhejiang, Anhui and Jiangsu. (iii) Technology progress is the most important influencing factor, all kinds of changing indicator show a trend of rise, and the total factor productivity is changing significantly. This research can provide theoretical reference for the YRDUA to achieve high-quality integration.

scholarly journals Analysis of the spatio-temporal network of air pollution in the Yangtze River Delta urban agglomeration, China

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262444
Author(s):  
Chuanming Yang ◽  
Qingqing Zhuo ◽  
Junyu Chen ◽  
Zhou Fang ◽  
Yisong Xu
Keyword(s):  
Air Pollution ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Urban Agglomeration ◽  
Temporal Network ◽  
The Yangtze River ◽  
The Cross ◽  
Spatio Temporal ◽  
The Yangtze River Delta

The complex correlation between regions caused by the externality of air pollution increases the difficulty of its governance. Therefore, analysis of the spatio-temporal network of air pollution (STN-AP) holds great significance for the cross-regional coordinated governance of air pollution. Although the spatio-temporal distribution of air pollution has been analyzed, the structural characteristics of the STN-AP still need to be clarified. The STN-AP in the Yangtze River Delta urban agglomeration (YRDUA) is constructed based on the improved gravity model and is visualized by UCINET with data from 2012 to 2019. Then, its overall-individual-clustering characteristics are analyzed through social network analysis (SNA) method. The results show that the STN-AP in the YRDUA was overall stable, and the correlation level gradually improved. The centrality of every individual city is different in the STN-AP, which reveals the different state of their interactive mechanism. The STN-AP could be subdivided into the receptive block, overflow block, bidirectional block and intermediary block. Shanghai, Suzhou, Hangzhou and Wuxi could be key cities with an all above degree centrality, betweenness centrality and closeness centrality and located in the overflow block of the STN-AP. This showed that these cities had a greater impact on the STN-AP and caused a more pronounced air pollution spillovers. The influencing factors of the spatial correlation of air pollution are further determined through the quadratic assignment procedure (QAP) method. Among all factors, geographical proximity has the strongest impact and deserves to be paid attention in order to prevent the cross-regional overflow of air pollution. Furthermore, several suggestions are proposed to promote coordinated governance of air pollution in the YRDUA.

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