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Civil aviation freight transport (CAFT) in China plays an important role in social and economic development. However, research on the morphological structure of China's CAFT network and its influence factors remains rare. In this paper, we focus on this topic by using a new data set of China's domestic routes from 2015 to 2019. With the complex network theory, we make an empirical study on the morphological structure of China's domestic CAFT network, and try to explore the nexus between the attributes of the network and the influence factors. The results show that China's domestic CAFT network is in line with the small world network model, which has a low average path length and a high clustering coefficient. The centrality of the network presents a saddle distribution with dense in the east and west, while sparse in the central. The results also indicate that there are many localized networks dominated by a few core airports. A number of regional hub cities exist, which are mainly located in the west of China. The development of China's CAFT highly depends on the civil aviation passenger transport (CAPT) network, and is highly affected by GDP, the industrial structure and the geographical location of cities. Finally, we give several policy suggestions, including developing the freight dedicated airports, establishing independent freight transport network system, vigorously developing core and intermediate hub cities, as well as constructing the regional network. • We study China's domestic civil aviation freight transport network by using a new dataset. • We analyze the network attributes and their influence factors at the city level. • A number of regional hub cities exist, mainly located in the west of China. • Civil aviation passenger transport, GDP and geographical location are the critical influencing factors of the network. [ABSTRACT FROM AUTHOR]

This study aimed to identify group variations in adolescent impulsivity and explore the connections between latent categories of impulsivity and psychological symptoms, social anxiety, and internet addiction. The research involved 2,378 participants from three middle schools in Guangdong Province, China. We assessed the impact of impulsivity levels (measured by BBIS) on depression (measured by KADS-11), anxiety (measured by SCARED), social anxiety (measured by SASC), and internet addiction (measured by YDQ). Latent profile analysis was employed to examine the diversity in adolescent impulsivity, establish latent classifications, and investigate the variances in psychological symptoms, social anxiety, and internet addiction. The middle school students were categorized into five latent groups based on their BBIS scores. Statistical analysis revealed five impulsivity categories, strongly linked to psychological symptoms and social anxiety but less strongly associated with internet addiction. The high impulsivity group (C5) exhibited higher scores in psychological symptoms and social anxiety compared to other groups, whereas the poor self-regulation group (C3) displayed greater psychological symptoms, social anxiety scores, and internet addiction than the impulsive behavior group (C4). Future investigations should investigate the underlying factors contributing to the observed differences among these groups. [ABSTRACT FROM AUTHOR]

Rockfill dams are generally constructed on thick overburden layers in mountainous and valley areas due to their high adaptability to complex geological and geographical conditions. The safety of rockfill dams is a research focus worldwide, especially with the increase of dam heights. Significant differential settlement may be induced by different embankment materials in a dam body and various stratum properties in thick overburden layers. The accurate prediction of settlement is particularly important to guarantee the serviceability and safety operation of rockfill dams. Therefore, a novel settlement forecasting model is proposed in this study. This model can achieve a successful prediction of dam settlement during the construction and operation periods. Compared with the traditional model, the settlement influential factors in the proposed model are determined based on the existing theory of coarse-grained soil deformation calculation, causing the selection of factors to have clearer physical meanings. Additionally, the geometric characteristics of the dam, the different material properties in various zones of the dam and the foundation, and the complicated external loading conditions are all considered. Then, the improved regression model for forecasting the settlement of dams is proposed. The proposed settlement forecasting model is further employed to estimate the deformation of a high rockfill dam in China. The results prove that this novel method shows high accuracy and agrees well with the monitoring consequences, and this method is superior to the traditional statistical regression model in predicting dam settlement during the construction period. [ABSTRACT FROM AUTHOR]

Procambarus clarkii is a commercially significant species both domestically and internationally, and has become the most extensively farmed fishery species in China. However, accurately assessing stocks is often challenging, especially for data-poor fisheries, which undermines effective fishery management. This study aims to identify gaps in the stock status of P. clarkii and provide guidance for effective aquaculture management to promote the sustainability in the P. clarkii aquaculture industry. A total of 2035 crayfish were collected to obtain length-frequency data from March 2016 to February 2017 in the Selection and Reproduction Center of Crayfish, Houhu management area, Qianjiang, China. The seasonally oscillating von Bertalenffy Growth Function (VBGF) was fitted using two optimized ELEFAN approaches (ELEFAN_SA, a simulated annealing algorithm; ELEFAN_GA, a genetic algorithm) to estimate the growth, mortality, and exploitation rates of P. clarkii population. ELEFAN_SA provided a better fit and was subsequently used to derive the following results: an asymptotic total length (L inf) of 130.86 mm, a growth coefficient (K) of 0.63 year−1, initial condition parameter (t 0) of −0.32 year−1, expected longecity (t max) of 4.44 year−1, a total mortality (Z) of 1.96 year−1, a natural mortality (M) of 0.58 year−1, a fishing mortality (F) of 1.38 year−1 and a exploitation rate (E) of 0.70. The Thompson and Bell model estimated the overall stock biomass at approximately 1.92 tons, with the biological reference levels of F 0.1 = 0.78 year−1, F 0.5 = 0.59 year−1, E 0.1 = 0.40, and E 0.5 = 0.30. The current F and E (1.38 year−1 and 0.70) exceeded the established thresholds, indicating a high risk of overexploitation of the P. clarkii population. Jones' length-based cohort analysis demonstrated P. clarkii individuals with a total length ranging from 86 mm to 102 mm were more vulnerable to fishing pressure, and that the current fishing selectivity primarily targeted at immature juvenile P. clarkii. The results of GTG-LBSPR model estimated the stock's spawning potential ratio (SPR) at 0.33, which was below the target SPR of 0.4, suggesting a possible ongoing recruitment overfishing. Based on the findings of this study, it strongly advocates for collaborative efforts among researchers, fishery managers, and fish farmers in finding practical and effective measures, such as implementing the size limit for the first capture, that ensure the long-term reproductive capacity and sustainability of P. clarkii populations. Furthermore, it highly encourages moderate fishing pressure on fast-growing and reproductive potential individuals to offset negative impacts of overfishing and promote high SPR and sustainability. • ELEFAN_SA yields a better fit in von Bertalenffy Growth Function using total length data of crayfish. • The fast-growing and reproductive potential individuals are exposed to high fishing pressure. • P. clarkii aquaculture faces a possible ongoing recruitment overfishing. [ABSTRACT FROM AUTHOR]