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The massive construction of high-speed rail has profoundly changed China, and it has also had a significant impact on air pollution in Chinese cities. Based on the panel data of 278 cities in China from 2003 to 2019, this paper makes an empirical study on the influence of high-speed rail on city-level air quality by using the opening of high-speed rail as a quasi-natural experiment and taking the method of progressive DID estimation model. The results show that: 1) The opening of high-speed rail significantly improves city-level air quality, and the conclusions are still valid after a series of robustness tests and dealing with endogenous problems. 2) The opening of high-speed rail has a heterogeneous effect on air quality in cities of different regions and different scales. 3) The opening of high-speed rail can promote technological progress and accelerate the upgrading of industrial structures, as well as reduce air pollution levels in neighboring cities through the spillover effect. 4) The opening of high-speed rail improves urban air quality through the substitution effect of air passenger transport. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new freight mode to describe how the designed HSR freight train serve for express delivery. We introduce the functions of the hubs and design the hybrid hub-and-spoke network of road-rail intermodal transportation from the perspective of planners, which features as single allocation rule and configures varying levels of hubs. The problem is accurately described by a mixed integer programming model with the objective to minimize total construction cost and total operation cost. We develop a hybrid heuristic algorithm based on a greedy strategy to obtain the levels of hubs, customer allocation and cargo routing. Taking the example of HSR freight network consisting of 50 cities in China, numerical experiments are conducted on the basis of forecasting data from the real-life express market to obtain the hub location schemes. The validity of the model and the performance of the algorithm are verified. [ABSTRACT FROM AUTHOR]

Naturalized plants play pivotal roles in local plant biodiversity and ecological functions; however, the drivers of naturalization remain poorly understood at a fine scale. Thus, understanding the processes of the development and dominance of alien plants in local natural habitats is of paramount importance. In the present study, we report for the first time the naturalization of Cydonia oblonga in China based on community structure and population dynamics at a fine scale. We conducted a comprehensive survey of the species through field community investigations, interviews, and a literature review. Cydonia oblonga is an ancient fruit tree with a long introduction history of over 4500 years worldwide and a cultivation history of over 2500 years in China. We analyzed C. oblonga community structure using the spatiotemporal substitution method and quantitatively analyzed population dynamics using a static life table, survivorship curve, and time series model to explore the naturalization processes. The following results were obtained. (i) The community comprised 31 coexisting vascular plant species (16 woody and 15 herbaceous species) belonging to 28 genera in 20 families. Rosaceae and Asteraceae were the two most dominant families. (ii) All individuals in the shrub layer as well as the C. oblonga population exhibited a roughly inverted J‐shaped basal diameter distribution. A complete age structure was noted, and the survival curve was classified as Deevey type II. According to time series analysis, the population is estimated to increase in the future, specifically of medium and large individuals. (iii) Religious exchange, potent resource competitiveness, and similarity with the native habitat may be the major drivers of the introduction and successful naturalization of C. oblonga. These results suggest that alien species closely related to native ones are more likely to invade, naturalize, and dominate communities in local habitats. [ABSTRACT FROM AUTHOR]

Aims and objectives To examine the prevalence of post-traumatic stress disorder symptoms and to explore the predictive factors of post-traumatic stress disorder symptoms among bereaved adolescents four years after the Yushu earthquake. Background On 14 April 2010, the 7·1-magnitude Yushu earthquake occurred in the high-altitude, hypoxia-prone regions primarily inhabited by ethnic minorities. Many adolescents lost their parents during the earthquake. This study examined post-traumatic stress disorder and its predictors among bereaved Tibetan adolescents four years after the trauma in China. Design This was a cross-sectional descriptive study. Methods This study used a cross-sectional design with 830 bereaved adolescents. Participant demographic data included gender, age and grade, and the earthquake exposure variables included the deceased relatives, whether they were buried, injured or amputated (non-life-threatening) and whether they witnessed a burial, injury or death. The post-traumatic stress disorder Checklist-Civilian version was used to assess the symptoms and prevalence of post-traumatic stress disorder, and the Coping Style Scale assessed coping styles. Results The results indicated that the prevalence of post-traumatic stress disorder was 19·3%. Individuals who were buried, injured or amputated (non-life-threatening), who witnessed a burial, injury or death, who suffered severe property loss during the earthquake and who had negative coping skills were the most likely individuals to have post-traumatic stress disorder symptoms. Conclusions The presence of post-traumatic stress disorder was very prevalent among adolescents four years after the Yushu earthquake. Effective mental health services should be developed to facilitate postdisaster recovery for bereaved adolescents at high risk for post-traumatic stress disorder. Relevance to clinical practice The findings in this study improve our understanding of post-traumatic stress disorder and related risk factors in bereaved adolescents in non-Western communities, providing useful information for rebuilding and relief work. [ABSTRACT FROM AUTHOR]

Background: Trends of asthma mortality vary widely all over the world, while the trends in China over the past 15 years are unknown. The aim of this study was to assess the trends of asthma mortality in China. Methods: Asthma deaths and demographic characteristics were collected from National Death Cause Datasets of Disease Surveillance System between 2004 and 2019. The data were analyzed with joinpoint regression analysis and age-period-cohort (APC) analysis for the mortality rate due to asthma in China. Results: Asthma mortality declined from 2.4 (95% confidence interval (CI): 2.3–2.5) per 100,000 in 2004 to 1.6 (95% CI: 1.5–1.7) per 100,000 in 2019. Age-adjusted asthma mortality rates decreased for men and women in urban and rural areas from 2004 through 2019. The decreasing trend of the mortality rate has slowed down substantially during 2007 and 2009. After that, the decreasing trend has stabilized. The asthma mortality rates generally have a positive relationship with the age of the population when controlling for period and cohort. The period trend decreased and then increased when controlling for age and cohort. Conclusions: We should pay more attention to asthma management plans or treatment for aging people who are facing higher risk of asthma death. [ABSTRACT FROM AUTHOR]

Cucumber (Cucumis sativus L.) is one of the main vegetable crops in China. The physiological cultivation mechanism and gene function characteristics of cucumber are of great significance to the construction of modern agriculture. Due to the low genetic transformation rate of cucumber, only in situ hybridization, which does not involve the progress of gene modified transformation, is convenient to study mRNA localization, so it is more suitable for determination on mRNA localization in the mature tissue of cucumber. At present, the existing in situ hybridization technology system is more suitable for cucumber meristem than for the mature tissue of cucumber seedlings. Therefore, we optimized the traditional plant in situ hybridization protocol. Taking a known gene CsNPF7.2 (Nitrate Transporter Families protein) as an example, we then optimized the steps of plant tissue culture, gene probe preparation, plant material sampling and fixation, preparation of cross section, hybridization pretreatment, hybridization incubation, chromogenic reaction, microscopy examination, and treatment after reaction termination in order to obtain a new RNA in situ hybridization technique suitable for identification on mRNA localization in mature tissues of cucumber seedlings. This optimized technique will ensure the yield of probes, the integrity of RNA molecules, and the clarity and integrity of plant tissue structure, which is conducive to the study of gene function and screening of key genes in cucumber. [ABSTRACT FROM AUTHOR]