Spatial-temporal pattern of ecosystem services and sustainable development in representative mountainous cities: A case study of Chengdu-Chongqing Urban Agglomeration.

The Sustainable Development Goals (SDGs) are essential measure for preserving the balance between human well-being and natural ecosystems. The benefit of preserving ecosystems health play a crucial role in promoting the SDGs by providing stable ecosystem services (ESs). However, the ecological health of mountainous cities is vulnerable, with relative low ecological resilience. To investigate the conflict between ecosystems and sustainable development, this study takes the Chengdu-Chongqing Urban Agglomeration as the study area. The major tasks and results in this study include: (1) using the entropy weighting method and the InVEST model, we combined remote sensing, geographic, and statistical data to quantify three types of SDGs (economic, social, environmental) and four ESs (water yield, soil conservation, habitat quality, carbon storage), and establish a localized sustainable development assessment framework that is applicable to the Chengdu-Chongqing Urban Agglomeration. The results show that from 2014 to 2020, the three types of SDGs exhibited an overall upward trend, with the lowest values occurring in 2016. The gap between different counties has narrowed, but significant regional differences still remain, indicating an unbalanced development status quo. Among the 142 counties, water yield and soil conservation values show a consistent downward trend but occupies significant interannual variations, while habitat quality and carbon storage values increases consistently each year. (2) using Spearman's nonparametric correlation analysis and multiscale geographically weighted regression model to explore the temporal variation and spatial heterogeneity of correlations between county ESs and SDGs. The results showed significant heterogeneity in the spatial trade-offs and synergies between ESs and SDGs, with two pairs of synergies weakening, seven pairs of trade-offs increasing, and the strongest negative correlation between Economic Sustainable Development Goals and habitat quality. (3) we applied the self-organizing mapping neural networks to analyze the spatial clustering characteristics of ESs-SDGs. Based on the spatial clustering effects, we divides the Chengdu-Chongqing Urban Agglomeration into four zones, and different zones have different levels of ESs and SDGs. The targeted strategies should be adopted according to local conditions. This work is of great practical importance in maintaining the stability and sustainable development of the Chengdu-Chongqing Urban Agglomeration ecosystem and provides a scientific reference for the optimal regulation of mountainous cities.

Identification of spatial protection and restoration priorities for ecological security pattern in a rapidly urbanized region: A case study in the Chengdu-Chongqing economic Circle, China.

The continuous expansion of modern cities not only leads to ecological degradation but also seriously threatens regional ecological security and sustainable development. The construction of ecological security patterns (ESPs) has emerged as a significant approach to alleviate or even solve the conflict between regional development and ecological protection. The Chengdu-Chongqing Economic Circle (CCEC) represents the core area of regional economic development strategy in western China, characterized by rapid economic growth from 2000 to 2020. This study integrates assessments of ecosystem services importance, eco-environmental sensitivity and landscape connectivity; uses circuit theory and hydrological analysis to establish a research framework for the spatiotemporal evolution of regional ESP; and develops an optimized ESP combined with the Major Function Oriented Zone. The results indicate that urban expansion significantly impacted the ESP of the CCEC between 2000 and 2020. The fragmentation and merging of ecological sources occurred simultaneously, the number of patches reduced by 28.13% from 64 to 46. The early ecological security network was compromised, leading to the disappearance or elongation of some ecological corridors. The number of ecological corridors decreased by 36.03% from 136 to 87; the total length was reduced by 29.92% from 7500.57 km to 5256.28 km. Urgent optimization of the ESP is needed, reducing the number of key ecological protection areas by 50% from 106 to 53 while increasing priority restoration areas by 13.51% from 37 to 42. The study also reveals the insufficiency of the current Major Function Oriented Zone in protecting linear corridors, necessitating focused attention on the protection and restoration of ecological sources and surrounding corridors in important development zones. Additionally, a spatial optimization strategy of "one shelter, two cores, and three regions" is proposed to enhance regional ecosystem stability and connectivity. The aim was to strike a balance between ecological protection and food security by recommending an ecological corridor width range of 30∼100 m. These research findings offer scientific guidance for ecological space protection and restoration in the CCEC, contributing to the enhancement of both scientific and rational ecological planning in rapidly urbanizing areas.

Interannual evolution of the chemical composition, sources and processes of PM2.5 in Chengdu, China: Insights from observations in four winters.

The air quality in China has improved significantly in the last decade and, correspondingly, the characteristics of PM2.5 have also changed. We studied the interannual variation of PM2.5 in Chengdu, one of the most heavily polluted megacities in southwest China, during the most polluted season (winter). Our results show that the mass concentrations of PM2.5 decreased significantly year-by-year, from 195.8 ± 91.0 µg/m3 in winter 2016 to 96.1 ± 39.3 µg/m3 in winter 2020. The mass concentrations of organic matter (OM), SO42-, NH4+ and NO3- decreased by 49.6%, 57.1%, 49.7% and 28.7%, respectively. The differential reduction in the concentrations of chemical components increased the contributions from secondary organic carbon and NO3- and there was a larger contribution from mobile sources. The contribution of OM and NO3- not only increased with increasing levels of pollution, but also increased year-by-year at the same level of pollution. Four sources of PM2.5 were identified: combustion sources, vehicular emissions, dust and secondary aerosols. Secondary aerosols made the highest contribution and increased year-by-year, from 40.6% in winter 2016 to 46.3% in winter 2020. By contrast, the contribution from combustion sources decreased from 14.4% to 8.7%. Our results show the effectiveness of earlier pollution reduction policies and emphasizes that priority should be given to key pollutants (e.g., OM and NO3-) and sources (secondary aerosols and vehicular emissions) in future policies for the reduction of pollution in Chengdu during the winter months.

The relationship between family function and the incidence of overweight/obesity in children and adolescents in Chengdu city, Sichuan province of China: based on latent profile analysis.

BACKGROUND: Overweight/obesity in children and adolescents has become a global health problem, and family function may be associated with its occurrence. Studies exploring the association between family function and overweight/obesity in children and adolescents were performed in Western and Taiwan, China. To date, related studies haven't been conducted in Mainland China. OBJECTIVES: To investigate the current status of overweight, obesity, and family function among children and adolescents in Chengdu, China, and to explore their associations. METHODS: Children and adolescents in five primary and middle schools were chosen by cluster sampling. Body Mass Index was used to measure the status of overweight and obesity, and the Chinese family assessment instrument was adopted to assess family function. Latent profile analysis and stepwise logistic regression were applied to identify family classification and explore the relationships between family function and overweight/obesity. RESULTS: A total of 7616 (84.92%) children and adolescents out of 8968 completed the study with qualified-filled questionnaires. Nine hundred and sixty-six (12.68%)participants were overweight and 656 (8.61%) were obese. The family function was categorized into three profiles: mild (63.93%), moderate (12.32%), and severe (23.75%) dysfunction. The prevalence of overweight was 12.16%, 14.71%, and 13.05% for mild, moderate, and severe family dysfunction, respectively. And the prevalence of obesity was 8.19%, 10.77%, and 8.62% respectively. Participants in moderate and severe dysfunction families were more likely to be overweight (moderate: OR = 1.27, 95% CI:1.01 ~ 1.59, P = 0.04; severe: OR = 1.38, 95% CI:1.15 ~ 1.66, P = 0.001) and obese (moderate: OR = 1.35, 95% CI:1.02 ~ 1.79, P = 0.03; severe: OR = 1.55, 95% CI:1.23 ~ 1.96, P < 0.001). Sociodemographic data such as gender, residence, grade, pocket money per week, the number of siblings, and the education level of the mother were all associated with the risk of being overweight/obese in children and adolescents. CONCLUSIONS: The problems of being overweight or obese exist among children and adolescents in Chengdu. And the risk of being overweight or obese increases along with the decrease in family function.

Spatiotemporal characteristics of air pollution in Chengdu-Chongqing urban agglomeration (CCUA) in Southwest, China: 2015-2021.

Studying the spatiotemporal characteristics of air pollutants in urban agglomerations and their response factors will help to improve the quality of urban living. In combining air quality monitoring data and wavelet analysis from the Chengdu-Chongqing urban agglomeration (CCUA), this study assessed the spatiotemporal distribution characteristics and influential factors of air pollutants on daily, monthly and annual scales. The results showed that the concentration of air pollutants in the CCUA has decreased year by year, and air quality has improved. Except for O3, pollutants in autumn and winter were higher than those in summer. The spatial distribution of air pollutants was obvious distributed in Chengdu, Chongqing, Zigong and Dazhou. Pollution incidents were mainly concentrated in winter. The 6 air pollutants and air quality index (AQI) have dominant periods on multiple time scales. AQI showed positive coherence with PM2.5 and PM10 on multiple time scales, and obvious positive coherence with SO2, CO, NO2 and O3 in the short term scale. AQI was not strongly correlated with the fire point, but exhibited obvious negative coherence in the long term scale. In addition, AQI showed an obvious positive correlation with temperature and sunshine hours in short term, and a clear negative correlation with humidity and rainfall. The research results of this paper will provide a reference for pollution prevention and control in the CCUA.

Spatial pattern and influencing factors of tourism based on POI data in Chengdu, China.

Based on the analysis of the spatial distribution characteristics and influencing factors of 2879 attractions POI in Chengdu, this paper studies the spatial distribution types, spatial concentration, and equilibrium of attractions by using standard deviation ellipse, geographic concentration index, and kernel density estimation. Buffer analysis, near analysis, correlation analysis, and grey relation analysis are used to study the influencing factors of tourism in Chengdu. The results show that: (1) The overall attractions POI in Chengdu is in an east-west direction, and except for other types of attractions POI, the remaining types are also in an east-west direction. (2) The spatial agglomeration areas of different types of attractions POI in Chengdu were quite different. Among them, parks and city squares were mainly concentrated in the central urban areas, namely Jinjiang, Qingyang, Jinniu, Wuhou, and Chenghua, forming a prominent gathering area. (3) There were differences in the influence degree of each factor on the spatial distribution of attractions POI. Topography and drainage, transportation, tourist source market, and other factors significantly correlated with the distribution of attractions, which were the main factors affecting the spatial distribution of attractions. Industrial development and economic population were also important factors affecting the distribution of attractions. Tourism is an important thrust for urban development. The study of the spatial distribution of tourism and its influencing factors has clear guiding significance for later tourism development, which can help optimize the integration of tourism resources, promote the cooperation of regional tourism development and provide a basis for decision-making for tourism development.

Towards the high-quality development of City Region Food Systems: Emerging approaches in China.

The outbreak of COVID-19 has underscored the vulnerability of our current food systems. In China, following a series of strategies in guaranteeing food security in the past decades, the pandemic has further highlighted the necessity to strengthen urban-rural linkages and facilitate the sustainable development of local agri-food systems. The study for the first time introduced the City Region Food Systems (CRFS) approach to Chinese cities and attempted to holistically structure, analyze and promote the sustainability of local food systems in China. Taking Chengdu as an example, the study first took stock of existing concepts and policies in China and the city, and defined the high-quality development goals of CRFS for Chengdu. An indicator framework was then developed to serve as a CRFS assessment tool for identifying existing challenges and potentials of local food systems. Further, a rapid CRFS scan using the framework was conducted in Chengdu Metropolitan Area, providing concrete evidence for potential policy interventions and practice improvement in the area. The study has explored new paradigm of analysis for food related issues in China and provided supporting tools for evidence-based food planning in cities, which collectively contribute to the food system transformation in a post-pandemic scenario.

Exhaust emission inventory of typical construction machinery and its contribution to atmospheric pollutants in Chengdu, China.

To study the emission characteristics of typical construction machinery in Chengdu, 12 construction machinery (excavators, bulldozers, loaders, and forklifts) under idling mode, moving mode, and working mode, were tested using a portable emission measurement system (PEMS). Under three operating modes, the typical construction machinery in the working mode was higher in the fuel-based average emission factors of PM2.5 and NOx, while the fuel-based average emission factors of HC and CO were higher in idling mode. Integrated the results of investigation on ownership and activity levels of construction machinery, an exhaust emission inventory of typical construction machinery of Chengdu in 2018 was established according to the recommendation method. The annual emission of PM2.5, NOx, HC, and CO were 1.67 × 106, 1.61 × 108, 3.83 × 106, and 1.26 × 107 kg, respectively, and the excavator contributed the maximum emissions, accounting for an average proportion of 43.95%. The emission of construction machinery in Chengdu exhibited a clear monthly trend, with the highest from April to October and the lowest from November to March. In addition, the exhaust emissions presented an obvious spot-like characteristics, and the high-value areas were mainly concentrated in the surrounding suburban counties such as Shuangliu Wenjiang etc. To reduce pollution from construction machinery and improve the quality of the atmospheric environment, more effective measures on housing construction and municipal construction should be taken in those districts in Chengdu.

Progressively narrow the gap of PM2.5 pollution characteristics at urban and suburban sites in a megacity of Sichuan Basin, China.

Nowadays, the fine particle pollution is still severe in some megacities of China, especially in the Sichuan Basin, southwestern China. In order to understand the causes, sources, and impacts of fine particles, we collected PM2.5 samples and analyzed their chemical composition in typical months from July 2018 to May 2019 at an urban and a suburban (background) site of Chengdu, a megacity in this region. The daily average concentrations of PM2.5 ranged from 5.6-102.3 µg/m3 and 4.3-110.4 µg/m3 at each site. Secondary inorganics and organic matters were the major components in PM2.5 at both sites. The proportion of nitrate in PM2.5 has exceeded sulfate and become the primary inorganic component. SO2 was easier to transform into sulfate in urban areas because of Mn-catalytic heterogeneous reactions. In contrast, NO2 was easily converted in suburbs with high aerosol water content. Furthermore, organic carbon in urban was much greater than that in rural, other than elemental carbon. Element Cr and As were the key cancer risk drivers. The main sources of PM2.5 in urban and suburban areas were all secondary aerosols (42.9%, 32.1%), combustion (16.0%, 25.2%) and vehicle emission (15.2%, 19.2%). From clean period to pollution period, the contributions from combustion and secondary aerosols increased markedly. In addition to tightening vehicle controls, urban areas need to restrict emissions from steel smelters, and suburbs need to minimize coal and biomass combustion in autumn and winter.

Novel ecological ditch system for nutrient removal from farmland drainage in plain area: Performance and mechanism.

The loading of nitrogen (N) and phosphorus (P) from agricultural drainage as the non-point sources is a worldwide environmental issue for aquatic ecosystem. However, how to remove these nutrients effectively from agricultural drainage remains a big challenge with increasing cemented ditches for better management. Here, we designed a novel ecological ditch system which integrated an earth ditch and a cemented ditch with iron-loaded biochar in the Chengdu Plain to reduce the loss of N and P from farmland. After a two-year monitoring, the removal efficiency of total N and total P reached 24.9% and 36.1% by the earth ditch and 30.7% and 57.8% by the integrated ditch system, respectively. The water quality was evidently improved after passing through the ditch system with the marked decrease in the concentrations of N and P. Dissolved organic N, nitrate, and particulate P became the dominant fractions of N and P loss. Rainfall soon after fertilization increased the concentrations of N and P in the ditch system and markedly affected their removal efficiency. The iron-loaded biochar effectively removed N and P from the drainage, especially at the high concentrations, which was mainly attributed to its high adsorption of the dissolved N and P fractions and the interception of the particulate nutrients. Our results indicate that the designed ecological ditch system has a high potential for alleviating agricultural non-point source pollution in the plain area and can be extended to other lowland agricultural ecosystems.

Atmospheric carbonyls in a heavy ozone pollution episode at a metropolis in Southwest China: Characteristics, health risk assessment, sources analysis.

Ambient carbonyls were continuously observed in the field during a heavy ozone pollution episode in Chengdu, China from August 4 to August 19, 2019, and the pollution characteristics, atmospheric photochemical reactivity, human health risk, and sources of carbonyls were analyzed. Fifteen carbonyls were quantified with average total mixing ratios of 20.38 ppbv Formaldehyde (9.86 ppbv), acetone (4.41 ppbv), and acetaldehyde (3.57 ppbv) were the three most abundant carbonyls. During the heavy ozone pollution episode, the concentration of carbonyls was found to be higher on pollution days than on the clean days, and relatively higher in the daytime, especially at noon on the pollution days. This was influenced by the intensity of photochemical reactions and precipitation. The "weekend effect" with the concentration of carbonyls was higher on the weekends than on the weekdays was pointed out. Formaldehyde, acetaldehyde and hexaldehyde were the dominant oxidative species during the observation. The carcinogenic and non-carcinogenic risk values of formaldehyde and acetaldehyde were higher on pollution days than on clean days, and these values were higher compared with those of other cities in China and abroad. Long-term exposure to these compounds should therefore be avoided. Diagnostic ratios and correlation analysis together with backward trajectory analysis showed that primary emission and secondary formation accounted 66%-76% and 24%-34% of carbonyls in Chengdu, respectively, with primary emission being the main sources of carbonyls, and carbonyls from the surrounding cities and emission from natural sources also had a significant contribution to the carbonyls in Chengdu.

Characteristics of ambient volatile organic compounds during spring O3 pollution episode in Chengdu, China.

Surface ozone (O3) has become a critical pollutant impeding air quality improvement in many Chinese megacities. Chengdu is a megacity located in Sichuan Basin in southwest China, where O3 pollution occurs frequently in both spring and summer. In order to understand the elevated O3 during spring in Chengdu, we conducted sampling campaign at three sites during O3 pollution episodes in April. Volatile organic compounds (VOCs) compositions at each site were similar, and oxygenated VOCs (OVOCs) concentrations accounted for the highest proportion (35%-45%), followed by alkanes, alkens (including acetylene), halohydrocarbons, and aromatics. The sensitivity of O3 to its precursors was analyzed using an observation based box model. The relative incremental reactivity of OVOCs was larger than other precursors, suggesting that they also played the dominant role in O3 formation. Furthermore, the positive matrix factorization model was used to identify the dominant emission sources and to evaluate their contribution to VOCs in the city. The main sources of VOCs in spring were from combustion (27.75%), industrial manufacturing (24.17%), vehicle exhaust (20.35%), and solvent utilization (18.35%). Discussions on VOCs and NOx reduction schemes suggested that Chengdu was typical in the VOC-limited regime, and VOC emission reduction would help to prevent and control O3. The analysis of emission reduction scenarios based on VOCs sources showed that the emission reduction ratio of VOCs to NO2 needs to reach more than 3 in order to achieve O3 prevention. Emission reduction from vehicular exhaust source and solvent utilization source may be more effective.

[Epidemiological Characteristics of Hand, Foot, and Mouth Disease and the Effect of EV71 Vaccination in Chengdu from 2012 to 2020].

Objective: To analyze the epidemiological characteristics of hand, foot, and mouth disease (HFMD) in Chengdu from 2012 to 2020, to make comparison in order to examine the changes in incidence before and after vaccination was introduced, and to provide basis for the prevention of HFMD in the future. Methods: Descriptive epidemiological methods were adopted to analyze the incidence, mortality and rate of severe cases of HFMD cases reported in Chengdu from 2012 to 2020. Results: From 2012 to 2020, the cumulative cases of HFMD reported in Chengdu were as many as 279216, of which, there were 2201 severe cases and 16 deaths. The incidence increased every other year, reaching 326.43 per 100000 person-years, the highest ever, in 2018. The rate of severe cases and mortality had shown a decreasing trend since 2016. A total of 11892 cases of EV71, CoxA16 and other enteroviruses were detected in the laboratory, accounting for 14.8%, 18.8% and 66.3%, respectively. Since 2016, HFMD cases caused by EV71 virus infection had shown an overall decreasing trend, cases caused by Cox A16 virus infection had increased every other year, and cases caused by other enteroviral infections had shown an overall increasing trend. The reported cases were mainly concentrated in children aged 0-5 years (92.1%), with those in the age group of 1-2 years reporting the highest number of cases. For children of different ages, male patients always outnumber female patients. The geographic distribution showed that the areas with high HFMD incidence were always located in the central part of Chengdu City, and the three districts with the highest incidence growth rate were Qingbaijiang District, Shuangliu District, and Longquanyi District. Temporal distribution of HFMD cases showed an obvious bimodal distribution, with most of the cases concentrated in May through August and October through December of each year. The number of new cases reached the highest (12309 cases) in July 2018. Conclusion: While continuing to promote EV71 vaccination in the future, Chengdu also needs to pay more attention to viral infection serotypes other than EV71 and Cox A16 and conduct research on multivalent vaccines against a variety of enteroviruses. The focus of prevention and control can be placed on areas with high population density, large floating populations, large numbers of agriculture-related communities, and insufficient individual awareness of hygiene. For the second circle of Chengdu city, the disinfection of agriculture-related communities should be strengthened, and information sessions or other health education activities could be organized for individuals and daycare facilities with low awareness of the importance of hygiene. In addition, more attention should be given to the prevention and control of HFMD in the high incidence seasons.

[Effectiveness of Different Testing Strategies Applied for Cervical Cancer Screening in Shuangliu District, Chengdu City].

Objective: To evaluate the clinical value of different combination strategies of high-risk HPV (hr-HPV) testing and Thinprep cytology test (TCT), a cervical cytology test, for cervical cancer screening, especially for high or higher-grade squamous intraepithelial lesion (HSIL+) in Shuangliu District, Chengdu City. Methods: The study is a population-based randomized clinical trial. Women aged 35 to 65 years meeting the inclusion criteria were enrolled for the study. At the baseline screening conducted in the first year, the participants were randomly assigned to either cytology test or hr-HPV testing at a ratio of 1∶2. If the paticipants had positive results for the baseline hr-HPV test, they would then undergo either cytology test or colposcopy by random assignment. After 24 months, all participants were called back, and combined screening of cytology test and hr-HPV test were performed. Women who had negative results at baseline screening and who entered and completed the third-year follow-up were selected as the subjects of the study. Based on the aforementioned testing findings, the related data were extracted and four different screening protocols were simulated: 1) combined TCT and hr-HPV screening, with referral for colposcopy when there was positive results for either one of the two; 2) combined TCT and hr-HPV screening, with referral for colposcopy when both tests had positive results at the same time; 3) TCT was done for preliminary screening and those who were found to be positive would then undergo hr-HPV test for triage purpose, with subsequent referral made for colposcopy if the hr-HPV results were positive; 4) hr-HPV was done for preliminary screening and those who were found to be positive would then undergo TCT, with subsequent referral made for colposcopy if TCT results were positive. With the detection of HSIL+ on histological examination as the endpoint event, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under curve ( AUC) of different combination screening models were calculated. Results: A total of 3102 women were screened, and 2967 women were included in the statistical analysis in this study. Among the 2967 women, 979 were randomized to cytology and 1988 to hr-HPV genotyping. For prescreening, the positive rate of the cytology group was 5.6% (55/979), with of HSIL+ positive rate being 0.2% (2/979), while the positive rate of the hr-HPV group was 7.5% (149/1988), with HSIL+ positive rate being 0.9% (18/1988). After 24 months, 2456 women were called back and were given cervical cytology test and hr-HPV test at the same time. Among them, the positive rate of the cytology group was 3.2% (78/2456), while the positive rate of hr-HPV group was 8.7% (215/2456). The overall positive rate of HSIL+ was 0.69%(17/2456). Women with a negative baseline hr-HPV had a lower incidence of HSIL+ lesions in the long term. The strategy of cervical cytology screening combined with hr-HPV test for triage purpose is the best method, with a sensitivity of 88.9%, a specificity of 58.3%, a PPV of 44.4%, a NPV of 93.3%, and an AUC of 0.736, P=0.039 (95% CI: 0.555-0.917). Conclusion: This randomized clinical trial from Shuangliu District, Chengdu City shows that the sensitivity of hr-HPV testing is better than that of cytology test, and the prevalence of HSIL+ in women with negative baseline hr-HPV results is lower than that of women with negative baseline cytology results. The screening program of TCT for prescreening plus subsequent hr-HPV test for triage purpose shows better value for the detection of HSIL+.

An Epidemiologic Survey and Violent Behavior Analysis of Antisocial Personality Disorder in Young Men in Chengdu.

OBJECTIVES: To investigate the epidemiological characteristics of antisocial personality disorder (ASPD) in young men in Chengdu and explore the characteristics and risks of violence. METHODS: Stratified random sampling was used to conduct a self-assessment questionnaire survey in 4 108 males aged from 18 to 34 in Chengdu, including general demographic characteristics, structured clinical interview for the diagnostic and statistical manual of mental disorders-Ⅳ axis Ⅱ disorders (SCID-Ⅱ) personality disorder screen questionnaire, violence questionnaire, psychosis screening questionnaire (PSQ), Alcohol Use Disorders Identification Test (AUDIT) and drug use. χ2 test, univariate and multivariate logistic regression were used for analysis and odds ratio (OR) was calculated. RESULTS: The positive rate of ASPD was 5.91%, which was associated with young age, unmarried, unemployment state, low educational level, violent behavior, psychotic symptoms, alcohol and drug use (P<0.05). Young men with ASPD also had a risk (P<0.05) of violence (OR was 8.51), multiple violence (OR was 16.57), injury (OR was 6.68), intentional violence (OR was 11.41), etc., the risk decreased after controlling for psychotic symptoms and substance abuse, but was still statistically significant. CONCLUSIONS: The risk of violence, severe violence and intentional violence in young men in Chengdu is high, and psychotic symptoms and substance abuse increase the risk of ASPD violence and relate characteristics.

Dietary shifts and diversities of individual life histories reveal cultural dynamics and interplay of millets and rice in the Chengdu Plain, China during the Late Neolithic (2500-2000 cal. BC).

OBJECTIVES: We undertook a more comprehensive analyses than our previous study (Yi et al., International Journal of Osteoarchaeology, 2018, 28, 636-644) at the Gaoshan site (~2500-2000 cal. BC) to expand our understanding of the different roles of rice and millets to human subsistence strategies, diachronic shift of human diets, diversity of human life histories and cultural influence (dental ablation) to human population. MATERIALS AND METHODS: Carbon and nitrogen isotopic analyses of human (ribs and long bones, n = 68) and animal (n = 15) bones as well as carbonized seeds from rice and millets (n = 8) were undertaken. Human bones were directly AMS-14 C dated. In addition, sequential sampling of 16 individuals with varied age and sex and cultural contexts for isotopic analysis was also conducted. RESULTS: The calibrated dating results (n = 27) indicate that there existed two periods of occupation at the site, ~2500-2200 BC and ~2200-1900 BC. Moderate high δ15 N values were found in the crops. Isotopic data from bone collagen suggest that the humans mainly relied on C3 -based animal protein and were supplemented by C4 -based foods. This isotopic pattern is also seen in pigs. Significant difference of human δ13 C values (Mann-Whitney U test, p < 0.05) between the two periods was observed. Compared to the bones, the isotopic data of human dentine serial sections show a much wider variability and higher δ13 C values. DISCUSSION: The crops (millets and rice) were probably manured. Human individuals subsisted on rice/millet agriculture and pigs in general. In combination with the radiocarbon dates, the increase of C3 (rice) consumption by the humans was found from the early (2500-2200 cal. BC) to late (2200-2000 cal. BC) periods, indicating the intensification of rice agriculture through time. However, four categories of human life histories during childhood are identified given different isotopic profiles of dentine sections, demonstrating that C3 (rice) and C4 (millets)-based foods played different roles in human lives. Even though, there were similar weaning practices among the human populations. It is surprising that human individuals with dental ablation, cultural characteristic in the Middle and Lower Yangtze River Valley, consumed more millets during childhood in the early period than those without dental ablation in the late period. Our study here provides novel insights into cultural dynamics and the interplay between rice and millets in rice-millet agricultural system during the Late Neolithic in Southwest China.

[Effects of Interaction between PM2.5 and O 3 8-h max on Mortality of Cardiovascular Diseases in Chengdu].

OBJECTIVE: To explore the health risks of the interactive effects between PM2.5 and ozone on cardiovascular mortality in Chengdu. METHODS: Daily data on the mortality of cardiovascular diseases, including data for both men and women, during 2014-2016 were collected. The meteorological data, the daily average of particulate matter with aerodynamic diameter less than 2.5 micrometers (PM2.5), and the daily ozone 8 h maximum concentration (O 3 8-h max) in Chengdu of the same period were also collected. Generalized Additive Models (GAMs) were adopted to explore the respective adverse health effects of PM2.5 and O 3 8-h max and the synergistic effects between PM2.5 and O 3 8-h max on the mortality of cardiovascular diseases in the city. RESULTS: The highest health risks of PM2.5 and O 3 8-h max for mortality of cardiovascular diseases were found to be the strongest for the cumulative effect of the lag of one day (lag01). For every 10 µg/m 3 increment in the mass concentration of PM2.5 (lag01), the associated increase in risks for total, male, and female cardiovascular mortalities was 0.35%, 0.26% and 0.38%, respectively. For every 10 µg/m 3 increment in the mass concentration of O 3 8-h max (lag01), the associated increase in risks for total, male, and female cardiovascular mortalities was 0.66%, 0.43%, and 1.05%, respectively. The total, male, and female cardiovascular mortalities all reached their maximum values when high concentration of PM2.5 coexisted with high concentrations of O 3 8-h max. CONCLUSION: There was a synergistic amplification effect between high concentrations of PM2.5 and high concentrations of O 3 8-h max on cardiovascular mortality.

Temporal and spatial distribution characteristics and source origins of volatile organic compounds in a megacity of Sichuan Basin, China.

As important pollution gases and represented precursors of both ozone and second organic aerosol (SOA), the component characteristics, source origins, environmental health and emission control of volatile organic compounds (VOCs), are gaining more and more attention in Chinese megacities. In order to understand the concentration, composition and temporal and spatial distribution characteristics of VOCs in the atmosphere of Chengdu, a megacity located in Sichuan basin in southwest China, the offline sampling measurements of VOCs were carried out at 28 different field sites covering all the districts and counties of Chengdu during special periods from May 2016 to January 2017. Speciated VOCs measurement was performed by the GC-FID/MS, and 99 species were identified. The averaged total VOC mixing ratios of each sampling site were in the range from 35.03 to 180.57 ppbv. Based on these observational data, the distribution characteristics of VOCs in different months and different regions of Chengdu were clarified. The VOCs data were used to estimate the potential amount of ozone, secondary aerosol formation and health risk assessment in Chengdu. Furthermore, the positive matrix factorization (PMF) model was used to identify the dominant emission sources and evaluate their contribution to VOCs in the city. The two main sources of VOCs in Chengdu were motor vehicle exhaust and solvent utilization. These accounted for 43% of all emission sources. In the summertime, due to higher temperatures and stronger sunlight, the contribution of natural sources and secondary emissions were also relatively high, which were supported by the regional emission inventories. Finally, the controlling direction of VOCs and O3 pollution in Chengdu was discussed, and the VOCs pollution control strategy was proposed for the near future.

Comparison of perceived sustainability among different neighbourhoods in transitional China: The case of Chengdu.

There have been increasing concerns about neighbourhoods' contextual characteristics and the importance of applying integrated sustainability principles to develop sustainable neighbourhoods. Among the contextual characteristics, the role of residents' perception of their neighbourhoods is critical when identifying various local sustainability issues and developing sustainable neighbourhood planning. However, little research has been done on evaluating residents' subjective perceptions of different neighbourhoods' sustainability performance, particularly in this time of transitional China. Thus, this research employed an empirical approach to investigate residents' perceived sustainability performance in three different neighbourhoods, including the traditional danwei, resettlement and commodity housing neighbourhoods in Chengdu. Questionnaire surveys and expert interviews were conducted to analyse the sustainability performance and critical sustainability issues in different neighbourhoods. The results demonstrated that infrastructure and public engagement were two common and significant factors affecting the sustainability of all three neighbourhoods. Most importantly, the three different neighbourhoods showed different sustainability challenges which called for developing contextual framework for sustainable neighbourhood development. Several theoretical and policy implications for planning were also provided.

[Distribution of traditional Chinese medicine syndrome types of male infertility in Chengdu area].

OBJECTIVE: To explore the distribution characteristics of the traditional Chinese medicine (TCM) syndrome types of male infertility in Chengdu area, China, in order to provide some objective evidence for the clinical treatment and studies of male infertility. METHODS: We collected the clinical data on 500 cases of male infertility treated in the outpatient and inpatient departments of the Affiliated Hospital of Chengdu University of Chinese Medicine and Chengdu Hospital for Reproduction, Women and Children from January to December 2017. Based on the results of examinations using the four diagnostic methods of TCM, namely, observation, auscultation and olfaction, interrogation, and palpation, we differentiated the TCM syndromes of the patients and analyzed the distribution characteristics of the syndrome types. RESULTS: Analysis of the baseline characteristics and the results of Chi-square test showed statistically significant differences in the distribution of the frequency of sexual intercourse, body mass index, history of urinary tract infection, testis volume, testicular texture, vas deferens and varicocele among the 500 patients (P < 0.05). As for the distribution of the TCM syndrome types, 115 cases (23.0%) were diagnosed with the unlicensed discernible type of syndrome, 109 (21.8%) with kidney-yang deficiency, 36 (7.2%) with kidney-essence deficiency, 30 (6.0%) with both kidney-yang deficiency and liver-qi stagnation, 30 (6.0%) with both kidney-yang deficiency and spleen-asthenia with excessive dampness, 28 (5.6%) with kidney-yin deficiency, 20 (4.0%) with spleen-asthenia and excessive dampness, 19 (3.8%) with liver-qi stagnation, 19 (3.8%) with phlegm dampness obstruction, 19 (3.8%) with kidney-yang and kidney-essence deficiency, 16 (3.2%) with downward damp-heat, 11 (2.2%) with both kidney-yin and kidney-yang deficiency, 10 (2.0%) with qi-stagnation and blood stasis, and 38 (7.6%) with other types of syndromes. CONCLUSIONS: The main TCM syndrome types of male infertility in Chengdu area include kidney-yang deficiency, kidney-yang deficiency with liver-qi stagnation, and kidney-yang deficiency with spleen-asthenia and excessive dampness. The distribution and influencing factors of the syndrome types need to be further explored and clarified by more large-sample and high-quality studies.