Urban environments offer a wealth of opportunities for residents to respite from their hectic life.Outdoor running or jogging becomes increasingly popular of an option.Impacts of urban environments on outdoor running,...Urban environments offer a wealth of opportunities for residents to respite from their hectic life.Outdoor running or jogging becomes increasingly popular of an option.Impacts of urban environments on outdoor running,despite some initial studies,remain underexplored.This study aims to establish an analytical framework that can holistically assess the urban environment on the healthy vitality of running.The proposed framework is applied to two modern Chinese cities,i.e.,Guangzhou and Shenzhen.We construct three interpretable random forest models to explore the non-linear relationship between environmental variables and running intensity(RI)through analyzing the runners'trajectories and integrating with multi-source urban big data(e.g.,street view imagery,remote sensing,and socio-economic data)across the built,natural,and social dimensions,The findings uncover that road density has the greatest impact on RI,and social variables(e.g.,population density and housing price)and natural variables(e.g.,slope and humidity)all make notable impact on outdoor running.Despite these findings,the impact of environmental variables likely change across different regions due to disparate regional construction and micro-environments,and those specific impacts as well as optimal thresholds also alter.Therefore,construction of healthy cities should take the whole urban environment into account and adapt to local conditions.This study provides a comprehensive evaluation on the influencing variables of healthy vitality and guides sustainable urban planning for creating running-friendly cities.展开更多
The effects of the built environment factors on urban vitality have attracted wide attention in the urban planning fields in recent years,but few studies have considered the variables’relative importance and their no...The effects of the built environment factors on urban vitality have attracted wide attention in the urban planning fields in recent years,but few studies have considered the variables’relative importance and their nonlinear effects on urban vitality.Taking a Chinese metropolis—Hangzhou as a case study,this study applied the gradient boosting decision tree(GBDT)model to explore the nonlinear effects of the 5D factors of the urban built environment on urban social vitality and economic vitality and the importance of variables.The results show that the GBDT model has better goodness of fit than the traditional ordinary least squares(OLS)regression in the urban vitality models.The urban built environment plays an important role in affecting urban vitality,while built environment designs witness the most important effect.Specifically,the density of shopping facilities,medical facilities,and road networks are the most important factors affecting urban social vitality,while road network density,destination accessibility,and population density play the most important roles in affecting urban economic vitality.Finally,the urban built environment factors have nonlinear threshold effects on both urban economic and social vitality in Hangzhou,with differing nonlinear response patterns observed between social and economic dimensions.展开更多
As global urbanization accelerates,the spatial vitality of historical urban areas has become a critical issue in urban regeneration and sustainable development.Some existing spatial vitality evaluation frameworks fail...As global urbanization accelerates,the spatial vitality of historical urban areas has become a critical issue in urban regeneration and sustainable development.Some existing spatial vitality evaluation frameworks fail to integrate multiple dimensions effectively,limiting their capacity to capture the dynamic complexity of these areas comprehensively.This study utilizes multi-source big data and deep learning technologies to propose a new multidimensional evaluation system for spatial vitality,improving existing models and systematically analyzing distribution patterns and formation mechanisms.The research results show that:(1)The spatial vitality of Changsha’s historical urban area exhibits a distinct“core-periphery”pattern.Core commercial zones show high vitality due to functional concentration,whereas peripheral areas have weaker vitality because of lower physical space quality and limited functional diversity.(2)Through correlation and principal component analyses,five key factors influencing spatial vitality were identified:emotional perception,visual aesthetics,spatial attractiveness,Functionality and Structure,and traffic conditions.(3)Bivariate spatial autocorrelation analysis further revealed spatial clustering effects between spatial vitality and its key factors,emphasizing the potential for enhancing functional diversity and optimizing road traffic conditions in core areas.The study’s findings offer scientific guidance for urban regeneration and policy-making,particularly in optimizing spatial layouts,enhancing vitality,and fostering the coordinated development of cultural heritage protection,providing valuable insights for other developing countries.展开更多
Hypergraphs,which encapsulate interactions of higher-order beyond mere pairwise connections,are essential for representing polyadic relationships within complex systems.Consequently,an increasing number of researchers...Hypergraphs,which encapsulate interactions of higher-order beyond mere pairwise connections,are essential for representing polyadic relationships within complex systems.Consequently,an increasing number of researchers are focusing on the centrality problem in hypergraphs.Specifically,researchers are tackling the challenge of utilizing higher-order structures to effectively define centrality metrics.This paper presents a novel approach,LGK,derived from the K-shell decomposition method,which incorporates both global and local perspectives.Empirical evaluations indicate that the LGK method provides several advantages,including reduced time complexity and improved accuracy in identifying critical nodes in hypergraphs.展开更多
Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vital...Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vitality has been extensively discussed.However,the moderating effect of housing vacancy on the built environment’s effect on urban vitality in shrinking cities has not been explored in detail.This paper selected Yichun District in Yichun City of Heilongjiang Province,a typical shrinking city in Northeast China,as the study area,focusing on the effect of the built environment on urban vitality in shrinking cities based on residential and commercial electricity consumption data for 2013 and 2018.Moreover,this study also explored the moderating mechanisms of residential and commercial housing vacancies on the built environment’s effect on urban vitality.The results demonstrate that the spatial pattern of urban vitality in the Yichun District is‘high in the center and low in the periphery’.Population density,building age,road density,and catering facilities are recognized as the main built environment factors affecting the vitality of shrinking cities.Residential and commercial housing vacancies have a significant moderating effect on the built environment’s effect on urban vitality.Residential housing vacancies enhance the positive effect of road density and the negative effect of greening rate.In addition,commercial housing vacancies suppress the positive effect of building density and enhance the positive effect of accessibility to urban service facilities.The study indicates that built environment factors exhibit heterogeneous effects on vitality in the context of urban shrinkage,as moderated by housing vacancies.Targeted regulation of built environment factors is of practical significance in realizing the internal development and vitality enhancement of shrinking cities.展开更多
The fresh pollen vitality, the effect of different storage conditions on the pollen vitality, and the difference of vitality among the species of seven species of Syringa were determined in Shenyang, China. The result...The fresh pollen vitality, the effect of different storage conditions on the pollen vitality, and the difference of vitality among the species of seven species of Syringa were determined in Shenyang, China. The results indicated that the pollen vi-tality (81.5%) of Syringa villosa was the highest among the seven tested species, followed by S. microphylla and S. meyeri, and that of S. oblata var. affinis was the lowest. The low temperature was the best condition for storage of pollen of Syringa, and the most proper temperature for the storage was 0-2 癈. The storability of S. microphylla was the best of all, and it could be stored over 60 days at the temperature of 0-2 癈, next was S. villosa and S. meyeri.展开更多
[Objective] This study aimed to investigate the effects of different salt concentrations on the root vitality of Limonium bicolor （Bunge） Kuntze. [Method] Limonium bicolor （Bunge） Kuntze was treated with 0, 100, 2...[Objective] This study aimed to investigate the effects of different salt concentrations on the root vitality of Limonium bicolor （Bunge） Kuntze. [Method] Limonium bicolor （Bunge） Kuntze was treated with 0, 100, 200 and 400 mmol/L NaCl, respectively. After two weeks, root vitality, biomass and other physiological indicators were measured. [Result] Salt stress had significant influences on the growth of roots. Root vitality of Limonium bicolor increased firstly and reduced gradually with the increase of salt concentration. [Conclusion] The results indicate that Limonium bicolor has certain salt tolerance ability at low salt concentrations; under relatively high salt concentrations, Limonium bicolor roots can maintain high vitality; however, with the continuous increase of salt concentration, Limonium bicolor roots are damaged, with decreasing vitality.展开更多
Summary:Changes of maximum expiratory flow at 25%and 50%of vital capacity(MEF2s and MEFso,respectively),and predominant parameters indicating small airways function in asthmatics before and after bronchodilator(BD)rev...Summary:Changes of maximum expiratory flow at 25%and 50%of vital capacity(MEF2s and MEFso,respectively),and predominant parameters indicating small airways function in asthmatics before and after bronchodilator(BD)reversibility test have been less interpreted.Our study aimed to investigate the clinical role of changes of MEF2s and MEFso before and after BD reversibility test in diagnosing asthma.Forced expiratory volume in the first second(FEV),MEF2s,and MEFso were measured before and after BD reversibility test in 207 asthmatic patients using standard process.Forty healthy individuals were enrolled as controls.Receiver operating characteristic(ROC)curve was used to assess the diagnostic accuracy of reversibility of MEF2s and MEFgo before and after BD reversibility test(OMEF 2s%and AMEF so%,respectively)in diagnosing asthma.Among these functional criteria,AMEF2;%and 0MEFs%≥25%performed the best diagnostic performance.The sensitivity,specificity,and accuracy of AMEF 25%≥25%as an objcctive diagnostic test for asthma were 63.29%,87.50%,and 67.21%,and of AMEFs0%≥25%were 79.23%,85.00%,and 80.16%,respectively.The area under the ROC curve of the indicators was 0.8203 and 0.9104,respectively.By contrast,an increase in FEV≥12%and 200 mL demonstrated a sensitivity of 62.32%,specificity of 82.50%,and accuracy of 65.59%in diagnosing asthma.The changes of MEF2s and MEFso before and after BD reversibility test may be of additional value in the clinical diagnosis of asthma,with cutoff values of 25%being the most.展开更多
The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and industry. As one of the prerequisites, land resources is re...The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and industry. As one of the prerequisites, land resources is required to be optimally allocated via land consolidation. Consequently, land consolidation contributes greatly to population agglomeration, industrial development and resources support under the context of combating rural decline. Based on the key elements affecting rural development, this paper elaborates the connotation of rural vitalization and land consolidation in the new era as well as their relationships. Furthermore, the paper analyzes the alternative paths for achieving rural vitalization via land consolidation, and discusses the future directions of land consolidation and rural vitalization. The conclusions are drawn as follows:(1) To cope with the loss and decline of the intrinsic elements in rural areas, rural vitalization is a development strategy aimed at realizing economic, political, cultural and ecological rejuvenation in rural area by reshaping socio-economic morphology and spatial pattern in rural territory.(2) From the perspective of rural vitalization, land consolidation is endowed with new connotation, which should not only target at activating the key elements of rural development, but also place emphasis on coordinating material space and spirit core as well as integrating the restructuring of the physical space and the rural governance system.(3) Land consolidation should be compatible with regional natural conditions and the current stage of socio-economic development. According to the principle of regional planning and classification strategy, the appropriate models and paths should be adopted to promote the benign interactions of population, land and industry based on engineering techniques and ecological means.(4) Under the background of national strategy of rural vitalization, it is necessary to reshape the value orientation of land consolidation based on a scientific understanding of urban-rural relations and rural territorial functions, coordinate land consolidation planning and rural vitalization planning under the unified spatial planning system, and explore the new model combining land consolidation and multifunctional agriculture.展开更多
Based on panel data from 1991, 2000 and 2010 at the county level in China, this study analyzed the coupling characteristics and spatio-temporal patterns of agricultural labor changes and economic development under rap...Based on panel data from 1991, 2000 and 2010 at the county level in China, this study analyzed the coupling characteristics and spatio-temporal patterns of agricultural labor changes and economic development under rapid urbanization using quantitative and GIS spatial analysis methods. Three primary conclusions were obtained.(1) During 1991–2010, China's agricultural labor at the county level showed a decreasing trend, down 4.91% from 1991 to 2000 and 15.50% from 2000 to 2010. In spatial distribution, agricultural labor force has evolved by decreasing eastward and increasing westward.(2) During 1991–2010, China's agricultural economy at the county level showed a sustained growth trend, with a total increase of 140.13%, but with clear regional differences. The proportion of agricultural output in national GDP gradually decreased, characterized by decreases in eastern China and increases in western China.(3) The coupling types of economic-labor elasticity coefficient are mainly growth in northwest China, for both the agricultural economy and labor, and are intensive in southeast China, with growth of the agricultural economy and reduction of agricultural labor. Regions with lagged, fading, and declining coupling types are generally coincident with the high incidence of poverty in China. However, different coupling types had a positive developing trend for 1991–2010. Finally, based on the coupling types and spatial distribution characteristics of economic-labor elasticity coefficients, some policy suggestions are proposed to promote the integration of the primary, secondary, and tertiary industries and the vitalization of rural economies.展开更多
Due to rapid development in the past decade, air transportation system has attracted considerable research attention from diverse communities. While most of the previous studies focused on airline networks, here we sy...Due to rapid development in the past decade, air transportation system has attracted considerable research attention from diverse communities. While most of the previous studies focused on airline networks, here we systematically explore the robustness of the Chinese air route network, and identify the vital edges which form the backbone of Chinese air transportation system.Specifically, we employ a memetic algorithm to minimize the network robustness after removing certain edges, and hence the solution of this model is the set of vital edges. Counterintuitively,our results show that the most vital edges are not necessarily the edges of the highest topological importance, for which we provide an extensive explanation from the microscope view. Our findings also offer new insights to understanding and optimizing other real-world network systems.展开更多
基金National Natural Science Foundation of China,No.42171455The Hong Kong RGC Research Impact Fund,No.R5011-23The Hong Kong General Research Fund,No.15204121。
文摘Urban environments offer a wealth of opportunities for residents to respite from their hectic life.Outdoor running or jogging becomes increasingly popular of an option.Impacts of urban environments on outdoor running,despite some initial studies,remain underexplored.This study aims to establish an analytical framework that can holistically assess the urban environment on the healthy vitality of running.The proposed framework is applied to two modern Chinese cities,i.e.,Guangzhou and Shenzhen.We construct three interpretable random forest models to explore the non-linear relationship between environmental variables and running intensity(RI)through analyzing the runners'trajectories and integrating with multi-source urban big data(e.g.,street view imagery,remote sensing,and socio-economic data)across the built,natural,and social dimensions,The findings uncover that road density has the greatest impact on RI,and social variables(e.g.,population density and housing price)and natural variables(e.g.,slope and humidity)all make notable impact on outdoor running.Despite these findings,the impact of environmental variables likely change across different regions due to disparate regional construction and micro-environments,and those specific impacts as well as optimal thresholds also alter.Therefore,construction of healthy cities should take the whole urban environment into account and adapt to local conditions.This study provides a comprehensive evaluation on the influencing variables of healthy vitality and guides sustainable urban planning for creating running-friendly cities.
基金National Social Science Foundation of China,No.20FJLB025National Natural Science Foundation of China,No.42471207,No.42471203Zhejiang Province Philosophy and Social Science Planning,Zhijiang Youth Special Project,24ZJQN118Y。
文摘The effects of the built environment factors on urban vitality have attracted wide attention in the urban planning fields in recent years,but few studies have considered the variables’relative importance and their nonlinear effects on urban vitality.Taking a Chinese metropolis—Hangzhou as a case study,this study applied the gradient boosting decision tree(GBDT)model to explore the nonlinear effects of the 5D factors of the urban built environment on urban social vitality and economic vitality and the importance of variables.The results show that the GBDT model has better goodness of fit than the traditional ordinary least squares(OLS)regression in the urban vitality models.The urban built environment plays an important role in affecting urban vitality,while built environment designs witness the most important effect.Specifically,the density of shopping facilities,medical facilities,and road networks are the most important factors affecting urban social vitality,while road network density,destination accessibility,and population density play the most important roles in affecting urban economic vitality.Finally,the urban built environment factors have nonlinear threshold effects on both urban economic and social vitality in Hangzhou,with differing nonlinear response patterns observed between social and economic dimensions.
基金funded by the National Natural Science Foundation of China(Grant No.52278059)the Natural Science Foundation of Hunan Province of China(Grant No.2024JJ8316).
文摘As global urbanization accelerates,the spatial vitality of historical urban areas has become a critical issue in urban regeneration and sustainable development.Some existing spatial vitality evaluation frameworks fail to integrate multiple dimensions effectively,limiting their capacity to capture the dynamic complexity of these areas comprehensively.This study utilizes multi-source big data and deep learning technologies to propose a new multidimensional evaluation system for spatial vitality,improving existing models and systematically analyzing distribution patterns and formation mechanisms.The research results show that:(1)The spatial vitality of Changsha’s historical urban area exhibits a distinct“core-periphery”pattern.Core commercial zones show high vitality due to functional concentration,whereas peripheral areas have weaker vitality because of lower physical space quality and limited functional diversity.(2)Through correlation and principal component analyses,five key factors influencing spatial vitality were identified:emotional perception,visual aesthetics,spatial attractiveness,Functionality and Structure,and traffic conditions.(3)Bivariate spatial autocorrelation analysis further revealed spatial clustering effects between spatial vitality and its key factors,emphasizing the potential for enhancing functional diversity and optimizing road traffic conditions in core areas.The study’s findings offer scientific guidance for urban regeneration and policy-making,particularly in optimizing spatial layouts,enhancing vitality,and fostering the coordinated development of cultural heritage protection,providing valuable insights for other developing countries.
文摘Hypergraphs,which encapsulate interactions of higher-order beyond mere pairwise connections,are essential for representing polyadic relationships within complex systems.Consequently,an increasing number of researchers are focusing on the centrality problem in hypergraphs.Specifically,researchers are tackling the challenge of utilizing higher-order structures to effectively define centrality metrics.This paper presents a novel approach,LGK,derived from the K-shell decomposition method,which incorporates both global and local perspectives.Empirical evaluations indicate that the LGK method provides several advantages,including reduced time complexity and improved accuracy in identifying critical nodes in hypergraphs.
基金Under the auspices of the National Natural Science Foundation of China(No.42171191,41771172,42201211,42401249)Science and Technology Development Plan Project of Jilin Province,China(No.20220508025RC)Young Scientist Group Project of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.2022QNXZ02)。
文摘Urban vitality is one of the key indicators of sustainable urban development and an important factor for shrinking cities to achieve internal optimization.The relationship between the built environment and urban vitality has been extensively discussed.However,the moderating effect of housing vacancy on the built environment’s effect on urban vitality in shrinking cities has not been explored in detail.This paper selected Yichun District in Yichun City of Heilongjiang Province,a typical shrinking city in Northeast China,as the study area,focusing on the effect of the built environment on urban vitality in shrinking cities based on residential and commercial electricity consumption data for 2013 and 2018.Moreover,this study also explored the moderating mechanisms of residential and commercial housing vacancies on the built environment’s effect on urban vitality.The results demonstrate that the spatial pattern of urban vitality in the Yichun District is‘high in the center and low in the periphery’.Population density,building age,road density,and catering facilities are recognized as the main built environment factors affecting the vitality of shrinking cities.Residential and commercial housing vacancies have a significant moderating effect on the built environment’s effect on urban vitality.Residential housing vacancies enhance the positive effect of road density and the negative effect of greening rate.In addition,commercial housing vacancies suppress the positive effect of building density and enhance the positive effect of accessibility to urban service facilities.The study indicates that built environment factors exhibit heterogeneous effects on vitality in the context of urban shrinkage,as moderated by housing vacancies.Targeted regulation of built environment factors is of practical significance in realizing the internal development and vitality enhancement of shrinking cities.
基金This research is supported by the NKBRSF (G1999043407-1) Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-406 & SCXZD0101).
文摘The fresh pollen vitality, the effect of different storage conditions on the pollen vitality, and the difference of vitality among the species of seven species of Syringa were determined in Shenyang, China. The results indicated that the pollen vi-tality (81.5%) of Syringa villosa was the highest among the seven tested species, followed by S. microphylla and S. meyeri, and that of S. oblata var. affinis was the lowest. The low temperature was the best condition for storage of pollen of Syringa, and the most proper temperature for the storage was 0-2 癈. The storability of S. microphylla was the best of all, and it could be stored over 60 days at the temperature of 0-2 癈, next was S. villosa and S. meyeri.
基金Supported by National High-Technology Research and Development Program(863)(2007AA091701)~~
文摘[Objective] This study aimed to investigate the effects of different salt concentrations on the root vitality of Limonium bicolor （Bunge） Kuntze. [Method] Limonium bicolor （Bunge） Kuntze was treated with 0, 100, 200 and 400 mmol/L NaCl, respectively. After two weeks, root vitality, biomass and other physiological indicators were measured. [Result] Salt stress had significant influences on the growth of roots. Root vitality of Limonium bicolor increased firstly and reduced gradually with the increase of salt concentration. [Conclusion] The results indicate that Limonium bicolor has certain salt tolerance ability at low salt concentrations; under relatively high salt concentrations, Limonium bicolor roots can maintain high vitality; however, with the continuous increase of salt concentration, Limonium bicolor roots are damaged, with decreasing vitality.
基金This project was supported by the National Natural Science Foundation of China(No.81970024)partly by Scientific Research Project of Wuhan Health Committee(No.WX16C45).
文摘Summary:Changes of maximum expiratory flow at 25%and 50%of vital capacity(MEF2s and MEFso,respectively),and predominant parameters indicating small airways function in asthmatics before and after bronchodilator(BD)reversibility test have been less interpreted.Our study aimed to investigate the clinical role of changes of MEF2s and MEFso before and after BD reversibility test in diagnosing asthma.Forced expiratory volume in the first second(FEV),MEF2s,and MEFso were measured before and after BD reversibility test in 207 asthmatic patients using standard process.Forty healthy individuals were enrolled as controls.Receiver operating characteristic(ROC)curve was used to assess the diagnostic accuracy of reversibility of MEF2s and MEFgo before and after BD reversibility test(OMEF 2s%and AMEF so%,respectively)in diagnosing asthma.Among these functional criteria,AMEF2;%and 0MEFs%≥25%performed the best diagnostic performance.The sensitivity,specificity,and accuracy of AMEF 25%≥25%as an objcctive diagnostic test for asthma were 63.29%,87.50%,and 67.21%,and of AMEFs0%≥25%were 79.23%,85.00%,and 80.16%,respectively.The area under the ROC curve of the indicators was 0.8203 and 0.9104,respectively.By contrast,an increase in FEV≥12%and 200 mL demonstrated a sensitivity of 62.32%,specificity of 82.50%,and accuracy of 65.59%in diagnosing asthma.The changes of MEF2s and MEFso before and after BD reversibility test may be of additional value in the clinical diagnosis of asthma,with cutoff values of 25%being the most.
基金Key Program of National Natural Science Foundation of China,No.41731286The Postdoctoral Science Foundation of China,No.2018M630197The Bagui Scholars Program of Guangxi Zhuang Autonomous Region.
文摘The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and industry. As one of the prerequisites, land resources is required to be optimally allocated via land consolidation. Consequently, land consolidation contributes greatly to population agglomeration, industrial development and resources support under the context of combating rural decline. Based on the key elements affecting rural development, this paper elaborates the connotation of rural vitalization and land consolidation in the new era as well as their relationships. Furthermore, the paper analyzes the alternative paths for achieving rural vitalization via land consolidation, and discusses the future directions of land consolidation and rural vitalization. The conclusions are drawn as follows:(1) To cope with the loss and decline of the intrinsic elements in rural areas, rural vitalization is a development strategy aimed at realizing economic, political, cultural and ecological rejuvenation in rural area by reshaping socio-economic morphology and spatial pattern in rural territory.(2) From the perspective of rural vitalization, land consolidation is endowed with new connotation, which should not only target at activating the key elements of rural development, but also place emphasis on coordinating material space and spirit core as well as integrating the restructuring of the physical space and the rural governance system.(3) Land consolidation should be compatible with regional natural conditions and the current stage of socio-economic development. According to the principle of regional planning and classification strategy, the appropriate models and paths should be adopted to promote the benign interactions of population, land and industry based on engineering techniques and ecological means.(4) Under the background of national strategy of rural vitalization, it is necessary to reshape the value orientation of land consolidation based on a scientific understanding of urban-rural relations and rural territorial functions, coordinate land consolidation planning and rural vitalization planning under the unified spatial planning system, and explore the new model combining land consolidation and multifunctional agriculture.
基金Key Program of National Natural Science Foundation of China,No.41731286The Postdoctoral Science Foundation of China,No.2018M630197
文摘Based on panel data from 1991, 2000 and 2010 at the county level in China, this study analyzed the coupling characteristics and spatio-temporal patterns of agricultural labor changes and economic development under rapid urbanization using quantitative and GIS spatial analysis methods. Three primary conclusions were obtained.(1) During 1991–2010, China's agricultural labor at the county level showed a decreasing trend, down 4.91% from 1991 to 2000 and 15.50% from 2000 to 2010. In spatial distribution, agricultural labor force has evolved by decreasing eastward and increasing westward.(2) During 1991–2010, China's agricultural economy at the county level showed a sustained growth trend, with a total increase of 140.13%, but with clear regional differences. The proportion of agricultural output in national GDP gradually decreased, characterized by decreases in eastern China and increases in western China.(3) The coupling types of economic-labor elasticity coefficient are mainly growth in northwest China, for both the agricultural economy and labor, and are intensive in southeast China, with growth of the agricultural economy and reduction of agricultural labor. Regions with lagged, fading, and declining coupling types are generally coincident with the high incidence of poverty in China. However, different coupling types had a positive developing trend for 1991–2010. Finally, based on the coupling types and spatial distribution characteristics of economic-labor elasticity coefficients, some policy suggestions are proposed to promote the integration of the primary, secondary, and tertiary industries and the vitalization of rural economies.
基金supported by the National Natural Science Foundation of China (Nos. 91538204, 61425014, 61521091)National Key Research and Development Program of China (No. 2016YFB1200100)National Key Technology R&D Program of China (No. 2015BAG15B01)
文摘Due to rapid development in the past decade, air transportation system has attracted considerable research attention from diverse communities. While most of the previous studies focused on airline networks, here we systematically explore the robustness of the Chinese air route network, and identify the vital edges which form the backbone of Chinese air transportation system.Specifically, we employ a memetic algorithm to minimize the network robustness after removing certain edges, and hence the solution of this model is the set of vital edges. Counterintuitively,our results show that the most vital edges are not necessarily the edges of the highest topological importance, for which we provide an extensive explanation from the microscope view. Our findings also offer new insights to understanding and optimizing other real-world network systems.
