Which Neighborhoods Have Easier Access to Online Home Delivery Services?A Spatiotemporal Accessibility Analysis in Nanjing,China

The rise in online home delivery services(OHDS)has had a significant impact on how urban services are supplied and used in recent years.Studies on the spatial accessibility of OHDS are emerging,but few is known about the temporal dimension of OHDS accessibility as well as the geographic and socioeconomic differences in the spatiotemporal accessibility of OHDS.This study measures the spatiotemporal accessibility of four types of OHDS,namely leisure,fresh and convenient,medical,and catering services.The geographic and socioeconomic disparities in the spatiotemporal accessibility of these four types of OHDS are then identified using spatial statistical methods and the Kruskal-Wallis test(K-W test).The case study in Nanjing,China,suggests that:1)spatiotemporal accessibility better reflects the temporal variation of OHDS accessibility and avoids overestimation of OHDS accessibility when only considering its spatial dimension.2)The spatiotemporal accessibility of OHDS varies geographically and socioeconomically.Neighborhoods located in the main city or neighborhoods with higher housing prices,higher population density,and higher point of interest(POI)mix have better OHDS spatiotemporal accessibility.Our study contributes to the understanding of OHDS accessibility from a spatiotemporal perspective,and the empirical insights can assist policymakers in creating intervention plans that take into account variations in OHDS spatiotemporal accessibility.

Influence of Information Technology on Social Spatial Behaviors of Urban Residents——Case of Nanjing City in China

Taking Nanjing as a case, the paper explains the spatial behavior differences existing in the information technology use among different groups of residents and households, by virtue of analyzing the survey data of urban households in the 11 districts of Nanjing, from the social, spatial, life and other non-technical angles. Also it makes various analyses and evaluation quantitatively and qualitatively on the social and spatial effect of information technology. The results show that the new technology is changing the social spatial behaviors of urban residents. New behavioral spaces of urban family such as telecommuting, email and QQ have begun to emerge. With the help of Internet, the communication scope of families has expanded greatly, and more new forms of publicizing community information have begun to emerge. Telecommunication contact forms have been developing swiftly, and their frequencies of contact have been increasing dramatically.

Influence of Atmospheric Particulate Matter on Ozone in Nanjing,China:Observational Study and Mechanistic Analysis

Particulate matter with diameters of 2.5 μm or smaller(PM_(2.5)) and ozone(O_3) are major pollutants in the urban atmosphere. PM_(2.5) can affect O_3 by altering the photolysis rate and heterogeneous reactions. However, these two processes and their relative importance remain uncertain. In this paper, with Nanjing in China as the target city, we investigate the characteristics and mechanism of interactions between particles and O_3 based on ground observations and numerical modeling.In 2008, the average concentrations of PM_(2.5) and O_3 at Caochangmen station are 64.6 ± 47.4 μg m^(-3) and 24.6 ± 22.8 ppb,respectively, while at Pukou station they are 94.1 ± 63.4 μg m^(-3) and 16.9 ± 14.9 ppb. The correlation coefficient between PM_(2.5) and O_3 is -0.46. In order to understand the reaction between PM_(2.5) and O_3, we construct a box model, in which an aerosol optical property model, ultraviolet radiation model, gas phase chemistry model, and heterogeneous chemistry model,are coupled. The model is employed to investigate the relative contribution of the aforementioned two processes, which vary under different particle concentrations, scattering capability and VOCs/NOxratios(VOCs: volatile organic compounds;NOx: nitric oxide and nitrogen dioxide). Generally, photolysis rate effect can cause a greater O_3 reduction when the particle concentrations are higher, while heterogeneous reactions dominate O_3 reduction with low-level particle concentrations.Moreover, in typical VOC-sensitive regions, O_3 can even be increased by heterogeneous reactions. In Nanjing, both processes lead to O_3 reduction, and photolysis rate effect is dominant. Our study underscores the importance of photolysis rate effect and heterogeneous reactions for O_3, and such interaction processes should be fully considered in future atmospheric chemistry modeling.

Genotoxicity evaluation and a primary risk assessment of organic pollutants in the drinking water sources of Nanjing, China

An increasing number of industrial, agricultural, and commercial chemicals in the aquatic environment leads to various deleterious effects on organisms, which is becoming an increasingly serious problem in China. In this study, the comet assay was conducted to investigate the genotoxicity to human body caused by organic concentrates in the drinking water sources of Nanjing City from Yangtze River of China, and health and ecology risk due to expose to these organic pollutants were evaluated with the multimedia environmental assessment system （MEAS）. For all the water samples, they were collected from four different locations in the drinking water sourcr samples, es of Nanjing City. The results of the comet assay showed that all the organic concentrates from the water samples could induce different levels DNA damages on human peripheral blood lymphocytes, and a statistically significant difference （p〈0.01） was observed compared with the solvent control, which demonstrated the genotoxicity was in existence. According to the ambient severity （AS） of individual compound, we had sorted out the main organic pollutants in the drinking water source of the four waterworks, and the results showed that there was some potential hazard to human body for all the source water, namely the total ambient severity （TAS） of health for each water source was more than 1. However, the TAS of ecology for each water source was less than 1, which indicated that it was safe to ecology. The results of this investigation demonstrate the application of the comet assay and the MEAS in aquatic environmental monitoring studies, and the comet assay found to be fast, sensitive, and suitable for genotoxicity monitoring programs of drinking water source.

Effects of Community Community Communication Technology(ICT) Usage on Community Satisfaction: Case Study in Nanjing, China

Future or smart community, which mainly refers to the development of community information and communication technology(ICT) platforms or devices, has received considerable attention from urban governments and scholars. However, only a few studies have been conducted to test the actual effects of using these community ICT platforms or devices on the community satisfaction of residents. Therefore, the present study conducts a survey in 40 communities in Nanjing, China and uses a mixed linear regression model to determine the relationship between community ICT usage and community satisfaction. Results indicate that residents with high-level community ICT usage are more satisfied with their community than those with low-level community ICT usage. Moreover, evident differences are observed regarding the influence of new commodity, old commodity and affordable housing communities in Nanjing. These findings are meaningful for the construction and development of future communities.

SPATIAL DIFFERENTIATION OF LAND TRANSFER——Case Study of Shanghai, Nanjing and Taizhou in Changjiang River Delta

The policy of land transfer has greatly influenced the macro economy of China with the commencement of another innovation of land use system. Therefore, it is urgent to put forward some rational and feasible suggestions for local government to manage the market of land transfer. Moreover, it is important in the field of study on agricultural land use change to analyze the spatial differentiation and structural specification of land transfer, which are caused by rural households＇ behavior. This paper selected I l factors covering four aspects of rural households＇ family structure, family location, family income structure and the natural quality of land resources, all of which influence the behavior differentiation of rural households, to establish the index model indicating spatial differentiation of land transfer. Results show that the spatial differentiation of land transfer can be divided into four degrees and three categories through analyzing rural households＇ questionnaires from Shanghai, Nanjing and Taizhou in the Changjiang （Yangtze） River Delta. Since up to 80% of rural households belong to middle degrees, it can be concluded that the rural land market develops evenly in the study areas. And it is also indicated that the natural quality of land resources and the maximum income of rural land are most important factors influencing the spatial differentiation of land transaction. Considering different factors, the countermeasures can be carried out to enhance the spatial differentiation of land transfer so as to promote economic development and social security of rural China. All in all, both micro- factors and macro-factors influencing rural households＇ behavior of rural land transfer should be taken into account in order to make spatial differentiation and structural specification of rural land transfer notable.

Relationship Between Urban Road Traffic Characteristics and Road Grade Based on a Time Series Clustering Model： A Case Study in Nanjing, China

With the increasing number of vehicles in large-and medium-sized cities challenges in urban traffic management, control, and road planning are being faced. Taxi GPS trajectory data is a novel data source that can be used to study the potential dynamic traffic characteristics of urban roads, and thus identify locations that show a notable lack of road planning. Considering that road traffic characteristics on their own are insufficient for a comprehensive understanding of urban traffic, we develop a road traffic characteristic time series clustering model to analyze the relationship between urban road traffic characteristics and road grade based on existing taxi trajectory data. We select the main urban area of Nanjing as our study area and use the taxi trajectory data of a single month for evaluating our method. The experiments show that the clustering model exhibit good performance and can be successfully used for road traffic characteristic classification. Moreover, we analyze the correlation between traffic characteristics and road grade to identify road segments with planning designs that do not match the actual traffic demands.

Spatial Characteristics and Influencing Factors of Urban Resilience from the Perspective of Daily Activity:A Case Study of Nanjing,China

Based on the connotation of urban resilience and the main contradictions of China's urbanization,urban resilience is placed within the main daily activities contradictory scene of the urban man-land system to build a theoretical framework of urban activity resilience.Relying on geographic big data,this study identifies the spatial characteristics of activity resilience,reveals the impact of activity environment on activity resilience in Nanjing,and proposes countermeasures.The main conclusions are as follows.1)Activity resilience presents a composite spatial structure of circles and clusters,and most areas are resilient but at a low level.2)There are significantly positive and negative global autocorrelation between activity resilience and activity scale,and activity stability.Simultaneously,there also exists a local spatial autocorrelation with the opposite positive and negative trends.3)Activity environment has a significant effect on activity resilience,and the degree and direction of influence among different dimensions and regions are heterogeneous.4)For activity resilience,it is necessary to increase the matching degree between the scale and stability of activities,and reduce the excessive concentration and flow of activities.For the activity environment,it is necessary to improve the accessibility of the ecological environment,strengthen the high-quality supply of the infrastructure environment,optimize the balance of the location environment,and promote the inclusiveness of the social environment.

Spatio-temporal Fragmentation of Leisure Activities in Information Era： Empirical Evidence from Nanjing, China

Activity fragmentation provides a new approach for understanding the transformation of urban space and function in the information era. Numerous theoretical and empirical studies have been conducted on activity fragmentation, but few studies have focused on the fragmentation of leisure activities. This study was intended to extend the extant literature by: 1) analysing the spatio-temporal fragmentation of physical and virtual leisure activities by using a dataset collected in Nanjing, China, and 2) evaluating the reasons of leisure activity fragmentation, as well as the potential spatial effect of activity fragmentation. The results indicated that virtual leisure activities are more fragmented than physical leisure activities, but the fragmentation of physical and virtual leisure activities varies on weekday and weekend, as well as in various locations and urban districts. In addition, the results suggested that sociodemographic factors and information and communication technology(ICT) variables distinctly affect the fragmentation of leisure activities. Meanwhile, the fragmentation of virtual leisure activities may enhance the transformation of traditional urban space by reallocating leisure activity times and locations.

Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China

Accurate information on the location and magnitude of vegetation change in scenic areas can guide the configuration of tourism facilities and the formulation of vegetation protection measures.High spatial resolution remote sensing images can be used to detect subtle vegetation changes.The major objective of this study was to map and quantify forest vegetation changes in a national scenic location,the Purple Mountains of Nanjing,China,using multi-temporal cross-sensor high spatial resolution satellite images to identify the main drivers of the vegetation changes and provide a reference for sustainable management.We used Quickbird images acquired in 2004,IKONOS images acquired in 2009,and WorldView2 images acquired in 2015.Four pixel-based direct change detection methods including the normalized difference vegetation index difference method,multi-index integrated change analysis(MIICA),principal component analysis,and spectral gradient difference analysis were compared in terms of their change detection performances.Subsequently,the best pixel-based detection method in conjunction with object-oriented image analysis was used to extract subtle forest vegetation changes.An accuracy assessment using the stratified random sampling points was conducted to evaluate the performance of the change detection results.The results showed that the MIICA method was the best pixel-based change detection method.And the object-oriented MIICA with an overall accuracy of 0.907 and a kappa coefficient of 0.846 was superior to the pixel-based MIICA.From 2004 to 2009,areas of vegetation gain mainly occurred around the periphery of the study area,while areas of vegetation loss were observed in the interior and along the boundary of the study area due to construction activities,which contributed to 79%of the total area of vegetation loss.During 2009–2015,the greening initiatives around the construction areas increased the forest vegetation coverage,accounting for 84%of the total area of vegetation gain.In spite of this,vegetation loss occurred in the interior of the Purple Mountains due to infrastructure development that caused conversion from vegetation to impervious areas.We recommend that:(1)a local multi-agency team inspect and assess law enforcement regarding natural resource utilization;and(2)strengthen environmental awareness education.

Spatial Accessibility to Shopping Malls in Nanjing,China:Comparative Analysis with Multiple Transportation Modes

This study attempts to evaluate the rationality of the spatial layout of shopping malls and identify the urban area with poor shopping mall accessibility,as well as to provide a reference and assist decision-making for planning.Using the case of Nanjing,China,this study developed a method to evaluate the accessibility of shopping malls by three transport modes(car traffic,public transit,and bicycle).Specially,we divide the urban space into a regular hexagonal grid and harvest the total travel time from each of 7204 hexagon centroids to each of 129 shopping malls using the Baidu Internet map.The door-to-door travel time approach is used to evaluate all travel stages(walking,waiting,transfer,and transportation)based on travel time calculations.We further divide the shopping malls into two levels(super-regional and regional)based on the Dianping App’s information and develop the indicator of accessibility to shopping malls:the number of shopping malls within tolerance time thresholds and apply the closest facility and cumulative opportunities methods to measure accessibility scores.The results show that the accessibility estimations vary greatly with transport modes.The accessibility of shopping malls presents a concentric ring trend centered on the city center under the car traffic and bicycle modes.And public transit accessibility tends to axially extend due to the topology of bus routes and metro lines.In particular,we observe that the accessibility of shopping malls in Nanjing has an uneven spatial distribution pattern,with high accessibility values in the central urban areas and lots of underserved areas in urban fringe regions.Based on the accessibility measurements,we finally map the poor accessibility area and propose corresponding implications for urban planning.

URBAN REGIONAL STRUCTURES TRANSFORMATION AND SUSTAINABLE DEVELOPMENT: CASE STUDY OF NANJING MEGALOPOLIS

s: Since 1978, many changes have happened on the background of urban regional structure in China, such as the economy system restructuring, the social transforming including the population flow accelerating and social demand diversifying and individualizing, the political and economic systems reforms, the rise of the real estate market and the changing relationship between human and nature. From the macroscopic view, these changes make the national urban system to be a newer pattern with a widening gap among the cities in spite of the rising of the cities as a whole. At the same, the urban land use structures are changing with both the trends of intensification and diversification, and the trends of the regional diversification and the economic integration. Besides, urban structures with multiple centers are emerging in several metropolitan areas in China. These changes and trends mentioned above are confirmed by a case study of Nanjing City, a growing metropolitan area in east China. The case study also points out some problems in urban regional structure reforming, especially the poor social and ecological considerations. We should pay more attention to some ideas like balance of intensification and decentralization, development of suburban centers and a reasonable mixing of the functional activities to develop a sustainable urban regional structure.

Urban Land-banking Planning:A New Instrument to Regulate Urban Land Supply-demand of Nanjing City

It is the major purpose of the paper to present the urban land-banking planning and its functions of promoting the urban land-banking system and land use administration.The urban land-banking system has the potential attribute of acting as an irreplaceable role in urban land administration,but its unexpected function-deviation has impacted its implementation effect in China.A few city governments are attempting to deal with the problem by the urban land-banking planning which is expected to contribute to the extension of urban function,optimization of urban patterns,promotion of urban core competitiveness and overall construction of the urban value chain.In this paper,we primarily discuss the necessity,functions,purposes and main contents of the urban land-banking planning.Subsequently,the implementing situation of the urban land-banking system in Nan- jing is analyzed,including its integrated mode,spatio-temporal quantitative distribution and main characteristics.Finally,the background and targets including total,compositions,space,and regulation points are gradually introduced to present the Nanjing land-banking planning version 2.

Coordinated Development of Population, Economy and Environment System and Diagnosis of Its Obstacle Factors in Nanjing

Promoting the coordinated development of regional population,economy and environment is beneficial to the realization of sustainable development.Based on the construction of evaluation index system of coordinated development of systems,the entropy weight-TOPSIS method and coupling coordination model,the coordinated development degree of population,economy and environment system in Nanjing was measured,and the temporal variation characteristics of each subsystem and their coordinated development degree form 1997 to 2016 were analyzed.The results showed that the development of population,economy system and environment system in Nanjing was generally in a continuous upward trend.Among them,the economy system developed fastest.The coordinated development degree of population,economy system and environment system in Nanjing was constantly increasing but still at a low level;the degree was only in the primary coordination phase,and its type was environment lagging.The economy subsystem and environment subsystem were important factors restricting the development of population,economy and environment in Nanjing,and the main obstacle factor was the production of industrial solid waste.The results above can provide a scientific basis for promoting the coordinated development of population,economy and environment system in Nanjing and achieving regional sustainable development.

Correction to:Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China

The article "Integrating cross-sensor high spatial resolution satellite images to detect subtle forest vegetation change in the Purple Mountains,a national scenic spot in Nanjing,China",written by Fangyan Zhu,Wenjuan Shen,Jiaojiao Diao,Mingshi Li and Guang Zheng,was originally pub-lished electronically on the publisher’s Internet portal(currently SpringerLink)on 14 May 2019 without open access.

Pattern and mechanism of urban spatial growth in Nanjing City, 1979-2007

Urban spatial growth has become a hot topic of geographic science and urban research. Exploring the patterns and mechanisms of urban growth is the prerequisite to understand the urbanization process of China. The paper provides a spatial analysis method of using Remote Sensing （RS） and Geographic Information System （GIS）. and presents major patterns and mechanisms of urban spatial growth during the period from 1979 to 2007 in Nanjing City. Firstly, the paper introohwes the data, study area and methodology of the research. Then. the patterns of urban spatial growth are identified Subsequently, the main mechanisms of urban spatial growth are analyzed Finally some conclusions are drawn definitely. The features of urban spatial growth in Nanjing are as follows： during 1979-1988, urban spatial growth of each district was stow. and the inner growth was in excess of suburban growth; during the period of 1988-2000. urban growth of suburban was in excess of inner city. the most insensitive growth appeared in the southeast, and the growth of each aspect was relatively insensitive expect ecst and west; during the period of 2000-2007, urban growth of suburban was violent, the most insensitive growth appeared in the southeast. and the urban growth of each direction was insensitive except the west. The mechanisms of urban spatial growth are complex, the main ones of which are social and economic development. Besides. the guiding of urban planning and influence of urban spatial structure are quite obvious.

Research on the Development Model of University Archives Cultural Products Based on Deep Learning

The products of an archival culture in colleges and universities are the final result of the development of archival cultural resources,and the development of archival cultural effects in colleges and universities should be an important part of improving the artistic level of libraries.The existing RippleNet model doesn’t consider the influence of key nodes on recommendation results,and the recommendation accuracy is not high.Therefore,based on the RippleNet model,this paper introduces the influence of complex network nodes into the model and puts forward the Cn RippleNet model.The performance of the model is verified by experiments,which provide a theoretical basis for the promotion and recommendation of its cultural products of universarchives,solve the problem that RippleNet doesn’t consider the influence of key nodes on recommendation results,and improve the recommendation accuracy.This paper also combs the development course of archival cultural products in detail.Finally,based on the Cn-RippleNet model,the cultural effect of university archives is recommended and popularized.

Early systemic anticoagulation reduces hospital readmission in acute necrotizing pancreatitis patients:A retrospective cohort study

Background:Early systemic anticoagulation(SAC)is a common practice in acute necrotizing pancreatitis(ANP),and its impact on in-hospital clinical outcomes had been assessed.However,whether it affects long-term outcomes is unknown.This study aimed to evaluate the effect of SAC on 90-day readmission and other long-term outcomes in ANP patients.Methods:During January 2013 and December 2018,ANP patients admitted within 7 days from the onset of abdominal pain were screened.The primary outcome was 90-day readmission after discharge.Cox proportional-hazards regression model and mediation analysis were used to define the relationship between early SAC and 90-day readmission.Results:A total of 241 ANP patients were enrolled,of whom 143 received early SAC during their hospitalization and 98 did not.Patients who received early SAC experienced a lower incidence of splanchnic venous thrombosis(SVT)[risk ratio(RR)=0.40,95%CI:0.26-0.60,P<0.01]and lower 90-day readmission with an RR of 0.61(95%CI:0.41-0.91,P=0.02)than those who did not.For the quality of life,patients who received early SAC had a significantly higher score in the subscale of vitality(P=0.03)while the other subscales were all comparable between the two groups.Multivariable Cox regression model showed that early SAC was an independent protective factor for 90-day readmission after adjusting for potential confounders with a hazard ratio of 0.57(95%CI:0.34-0.96,P=0.04).Mediation analysis showed that SVT mediated 37.0%of the early SAC-90-day readmission causality.Conclusions:The application of early SAC may reduce the risk of 90-day readmission in the survivors of ANP patients,and reduced SVT incidence might be the primary contributor.

Fiber optic monitoring of an anti-slide pile in a retrogressive landslide

Anti-slide piles are one of the most important reinforcement structures against landslides,and evalu-ating the working conditions is of great significance for landslide mitigation.The widely adopted analytical methods of pile internal forces include cantilever beam method and elastic foundation beam method.However,due to many assumptions involved in calculation,the analytical models cannot be fully applicable to complex site situations,e.g.landslides with multi-sliding surfaces and pile-soil interface separation as discussed herein.In view of this,the combination of distributed fiber optic sensing(DFOS)and strain-internal force conversion methods was proposed to evaluate the working conditions of an anti-sliding pile in a typical retrogressive landslide in the Three Gorges reservoir area,China.Brillouin optical time domain reflectometry(BOTDR)was utilized to monitor the strain distri-bution along the pile.Next,by analyzing the relative deformation between the pile and its adjacent inclinometer,the pile-soil interface separation was profiled.Finally,the internal forces of the anti-slide pile were derived based on the strain-internal force conversion method.According to the ratio of calculated internal forces to the design values,the working conditions of the anti-slide pile could be evaluated.The results demonstrated that the proposed method could reveal the deformation pattern of the anti-slide pile system,and can quantitatively evaluate its working conditions.