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The intensification of global heat wave events is seriously affecting residents' emotional health. Based on social media big data, our research explored the spatial pattern of residents' sentiments during heat waves (SDHW). Besides, their association with urban functional areas (UFAs) was analyzed using the Apriori algorithm of association rule mining. It was found that SDHW in Beijing were characterized by obvious spatial clustering, with hot spots predominately dispersed in urban areas and far suburbs, and cold spots mainly clustered in near suburbs. As for the associations with urban function areas, green space and park areas had significant effects on the positive sentiment in the study area, while a higher percentage of industrial areas had a greater impact on negative SDHW. When it comes to combined UFAs, our results revealed that the green space and park area combined with other functional areas was more closely related to positive SDHW, indicating the significance of promoting positive sentiment. Subdistricts with a lower percentage of residential and traffic areas may have a more negative sentiment. There were two main combined UFAs that have greater impacts on SDHW: the combination of residential and industrial areas, and the combination of residential and public areas. This study contributes to the understanding of improving community planning and governance when heat waves increase, building healthy cities, and enhancing urban emergency management. [ABSTRACT FROM AUTHOR]

The Beijing-Tianjin-Hebei urban agglomeration was used to construct a comprehensive evaluation index system for urban waterlogging prevention and control resilience from five aspects: social resilience, economic resilience, ecological resilience, infrastructure resilience, and institutional resilience. The fuzzy VIKOR method was used to evaluate urban waterlogging prevention and control resilience. The results were analyzed at temporal and spatial scales to reveal regional differences and constraints in urban waterlogging prevention toughness and efficiently locate vulnerable urban areas. The resilience level in most of the Beijing-Tianjin-Hebei region increased during 2015–2019, while that of Beijing, Tianjin, Qinhuangdao, and Handan slightly decreased, indicating that the capacity of these cities to manage waterlogging disasters needs strengthening. The spatial difference in urban waterlogging prevention toughness was significant: Beijing, Tianjin, Handan, Tangshan, Langfang, and Shijiazhuang showed medium and high levels of urban waterlogging prevention toughness; other cities showed low levels. How the expansion speed of the urban scale matches the construction speed of urban waterlogging prevention and control directly affects resilience at all levels. These results support urban waterlogging control and regional integration construction for Beijing-Tianjin-Hebei. [ABSTRACT FROM AUTHOR]

Urban resilience assessment is crucial to guarantee the safe and stable operation of our cities. Looking at the whole process of emergencies from the occurrence, development, causing disaster losses to taking emergency response measures, we combine the danger of urban accident and disaster, the capacity of disaster-bearing carriers, and the emergency management capacity as the influencing factors. Taking Beijing as an example, considering the completeness of the relevant indicators and the difficulty of obtaining data, TOPSIS is used to construct a multi-factor comprehensive assessment model of urban safety resilience; At the same time, the important factors constraining the improvement of safety resilience are further analyzed by using the obstacle degree model. The results show that: among the 16 districts in Beijing, Chaoyang and Haidian districts have the highest level of safety resilience; the level of the degree of disaster tolerance among the multi-factors has the greatest impact on the level of urban safety resilience in Beijing; and the multifactorial comprehensive assessment model of urban resilience is able to reflect the urban resilience distribution, discover the weaknesses that exist in the development of urban safety and provide decision-making aids for the relevant city managers to carry out urban resilience construction. [ABSTRACT FROM AUTHOR]

Campylobacter jejuni (C. jejuni) is considered as an opportunistic zoonotic pathogen that may cause gastroenteritis in humans and other animals. Wild birds may be as potential vectors of C. jejuni around urban and suburban areas. Here, 520 samples were collected from 33 wild bird species in urban and suburban areas, Beijing. In total 57 C. jejuni were isolated from seven species. It was found that Nineteen (33.33%, 19/57) isolates were resistant to at least one of 11 antibiotics, especially streptomycin (36.84%) and four isolates resistant to all. Nineteen (33.33%, 19/57) isolates were multi-drug resistance. Multilocus sequence typing (MLST) analysis of the isolates showed that 36 different sequence types (STs) belonged to four Clonal complexes and unassigned. Twenty STs (55.56%) and six alleles among them were first detected. Virulence genes including flaA , cadF , and the cytolethal distending toxin (CDT) gene cluster, were detected in all isolates, but truncated cdt gene clusters only detected in the isolates from the crow, daurian jackdaw and silver pheasant. In conclusion, it was the first detection of C. jejuni involved truncated cdt gene clusters from the silver pheasant. These wild birds around urban and suburban areas may pose potential public health problems as reservoir vectors of C. jejuni. [ABSTRACT FROM AUTHOR]

The regional economy, population and ecology are closely linked in regional development, and the study of the harmonization between these systems contributes to the sustainable development of cities. In this study, 43 cities in the Bohai Rim region (BRR) urban agglomeration of China were selected for investigation in 2000, 2010, and 2020. By introducing an ecological subsystem indicator (Gross Ecosystem Product (GEP)) applicable to the study area, a coupled coordination degree (CCD) model relating ecology, economy and population was developed to explore the mechanism of sustainable development among the considered cities. The results indicated the following: the BBR GEP increased significantly over the study period, and Beijing and Tianjin exhibited the highest GEP values. The obvious increase in the CCD demonstrated that coordinated development of the BRR has improved since 2000, the center of gravity of coordination has shifted southwards, and stable high-high agglomeration occurs. This study is important for optimizing the strategic layout of regional development, enhancing regional synergy, and promoting high-level and high-quality regional development. [ABSTRACT FROM AUTHOR]

It has been widely recognized that urban green space provides various benefits to old adults. However, there is a lack of discussion about the impact of cultural ecosystem services (CES) of green space on seniors' mental health. We selected 20 parks in the old urban areas of Beijing and collected a total of 693 valid questionnaires from senior residents. Structural equation models were applied to examine the linkage between characteristics of parks (including green space, neighborhood environment, CES) and senior residents' self-reported mental health, with respondents' physical activity, social interaction, and satisfaction as mediators. Results highlighted the superiority of CES among all variables in promoting the subjective mental health of senior residents. In addition, we found the mediating role of the satisfaction with parks and social interaction in the linkage between CES and mental health. Moreover, results suggested that the area of green space was not directly related to mental health, but positively influenced older adults' mental health by enhancing their physical activity. Besides, we also found that neighborhood environment around a park may directly and positively affect seniors' mental health, while negatively affecting it by adversely affecting satisfaction with the park. These findings reflect the superiority of cultural ecosystem services in enhancing older adults' mental health, which enriches the original green space-health framework, and may have direct implication for the conservation of cultural landscape in the future. • We selected 20 parks in the old urban areas of Beijing as study sites. • The CES of a park positively affected subjective mental health among older adults by promoting their satisfaction and social interaction. • The area of green space was not directly related to mental health, but positively influenced older adults' mental health by enhancing their physical activity. • Neighborhood environment could directly and positively influence seniors' mental health, while negatively impact it by adversely affecting satisfaction with the park. [ABSTRACT FROM AUTHOR]

PM2.5 level has decreased significantly in Beijing in recent years due to the strict air quality control measures taken in Jingjinji Region and the surrounding areas. However, the variation characteristics of the concentrations of PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in Beijing in recent years are still not so clear. In order to understand the pollution status of PM2.5-bound PAHs in Beijing, fifteen PAHs were measured in a typical urban area of Beijing from 1 March to 20 March 2018. The average mass concentration of the 15 PAHs was 21 ng/m3 and higher in the nighttime than that in the daytime. The proportion of 4-ring PAHs in 15 PAHs was highest (43%), while 6-ring PAHs was lowest (10%). The levels of PAHs were higher during heavy pollution episodes than those in non-heavy pollution episodes, and the proportions of 5- and 6-ring PAHs were increased during a heavy pollution episode. PAHs posed obvious carcinogenic risks to the exposed populations, and the risk was higher during heavy pollution episodes than the average value of the whole monitoring period. The main sources of PAHs were traffic emissions and coal/biomass burning. Air masses from the south-southeast had a great influence on the PM2.5 levels during a heavy pollution episode. It is recommended that not only the PM2.5 levels but also the PAHs levels bounded in PM2.5 should be controlled to protect human health in Beijing. [ABSTRACT FROM AUTHOR]

The identification of urban functional areas is essential for urban planning and sustainable development. Spatial grids are the basic units for the implementation of urban plans and management by cities or development zones. The emergence of internet "big data" provides new ideas for the identification of urban functional areas. Based on point of interest (POI) data from Baidu Maps, the Xicheng District of Beijing was divided into grids with side lengths of 200, 500, and 1000 m in this study. The kernel density method was used to analyze the spatial structure of POI data. Two indicators, that is, the frequency density and category ratio, were then used to identify single- and mixed-functional areas. The results show that (1) commercial and financial areas are concentrated in the city center and multiple business centers have not developed; (2) scenic areas account for the largest proportion of single-functional areas in the Xicheng District of Beijing, followed by education and training, residence, and party and government organizations areas; and (3) the 200 × 200 m and 500 × 500 m grids are the most suitable for the identification of single- and mixed-functional areas, respectively. [ABSTRACT FROM AUTHOR]

It is meaningful to analyze urban spatial structure by identifying urban subcenters, and many methods of doing so have been proposed in the published literature. Although these methods are widely applied, they exhibit obvious shortcomings that limit their further application. Therefore, it is of great value to propose a new urban subcenter identification method that can overcome these shortcomings. In this paper, we propose the density contour tree (DCT) method for detecting urban polycentric structures and their spatial distributions. Conceptually, this method is based on an analogy between urban spatial structure and terrain. The point-of-interest (POI) density is visualized as a continuous mathematical surface representing the urban terrain. Peaks represent the regions of the most frequent human activity, valleys represent regions with small population densities in the city, and slopes represent spatial changes in urban land-use intensity. Using this method, we have detected the urban "polycentric" structure of Beijing and determined the corresponding spatial relationships. In addition, several important properties of the urban centers have been identified. For example, Beijing has a typical urban polycentric structure with an urban center area accounting for 5.9% of the total urban area, and most of the urban centers in Beijing serve comprehensive functions. In general, the method and the results can serve as references for the later research on analyzing urban structure. [ABSTRACT FROM AUTHOR]

Rapid urbanization is reducing the limited urban public space available for residents to improve urban life. SDG 11.7.1 is used to assess the equity of urban public spaces, but it focuses only on the equity of public space at the city level, ignoring whether the public space resources in areas within the city match the needs of residents. Therefore, this paper proposes a multi-level framework for assessing the spatial equity of urban public space towards SDG 11.7.1. Based on this, the calculation method of SDG 11.7.1 is refined and the progress of SDG 11.7.1 is assessed at the city level. Then, the spatial equity of open public spaces (OPS) at the grid level is explored based on an improved 2SFCA model. The results show that Beijing has made rapid progress in promoting the implementation of SDG 11.7.1, but there is still a significant gap in the requirements of SDG 11.7. In addition, the spatial equity assessment results indicate significant spatial inequity in the allocation of OPS resources in Beijing. The study can provide a scientific reference for other cities to conduct quantitative measurements of SDG 11.7.1, and a scientific basis for planners and policy-makers to allocate urban OPS more rationally and equitably. • Expands the scientific connotations of SDG 11.7.1 from a spatial equity perspective. • Proposed a multi-level framework to explore the spatial equity of OPS towards SDG 11.7.1. • Accesses the status, gap and actions in the implementation of SDG 11.7.1 in Beijing. • Provided experience and demonstration for similar city-level assessments. [ABSTRACT FROM AUTHOR]

This paper proposes a hierarchical Bayesian network model (BNM) to quantitatively evaluate the resilience of urban transportation systems. Based on systemic thinking and taking a sustainability perspective, we investigate the long-term resilience of the road transportation systems in four cities in China from 1998 to 2017, namely Beijing, Tianjin, Shanghai, and Chongqing, respectively. The model takes into account various factors collected from multi-source data platforms involved in stages of design, construction, operation, management, and innovation in road transportation systems. We test the model with the forward inference, sensitivity analysis, and backward inference. The result shows that the overall resilience scores of all four cities' transportation systems are within a moderate range with values between 49% to 59%. Although they all have an ever-increasing economic level, the levels of transportation resilience in Beijing and Tianjin decrease first and then gradually increase in a long run, which indicates a strong multi-dimensional, dynamic, and non-linear characteristic in resilience-economic coupling effect. Additionally, the results obtained from the sensitivity analysis and backward inference suggest that decision makers should pay more attention to the capabilities of quickly rebuilding and making changes to cope with future disturbances. As an exploratory study, this study clarifies the concepts of long-term multi-dimensional resilience and specific hazard-related resilience and provides an effective decision-support tool for stakeholders when building resilient infrastructure. • A novel BNM is proposed to evaluate multi-faceted transportation resilience. • Forward inference, sensitivity tests, and backward inference are conducted. • Long-term transportation resilience is highly dynamic in the tested cities. • The coupling effects of resilience with economic level is not always linear. • Abilities to rebuild and adapt through reconfiguration are of importance. [ABSTRACT FROM AUTHOR]