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On July 20, 2013, a landslide-induced debris flow occurred in Dujiangyan city, China. Eleven houses were destroyed with more than 166 fatalities. Previous literature indicated that the 2008 Ms 8.0 earthquake and a long period of heavy rain contributed to this landslide. The rock slide was initiated and 21% of the rupture mass fell from the cliff. These rocks fragmented when impacting the ground and then entrained the base soil. Subsequently, the volume of rockfall increased by 28%. In an area of flow convergence, a short-lived blockage occurred, and the following outburst triggered a debris flow. Previous field investigations have shown that both topography and bed entrainment affect the landslide-debris flow transformation. However, the dynamic process has not been quantified. In this study, the discrete element method (DEM) considering the dragging and rolling effects was used to perform a back numerical analysis to capture the dynamic processes. The computational results indicate two different entrainment scenarios, plowing and shearing. The former occurred when the rock slide detached from the cliff, and the latter occurred when debris material moved above the colluvium. The landslide transformed into a debris flow during a short-term blockage that occurred in the gradually narrowing channel. During flow convergence, the inertial shearing stress developed due to the inter-particle collision. [ABSTRACT FROM AUTHOR]

The health effects of urbanization are controversial. The association between urbanization and reversible subclinical risks of cardiovascular diseases (e.g., electrocardiogram (ECG) abnormalities) has rarely been studied. This study aimed to assess the association between urbanization and ECG abnormalities in China based on the China National Stroke Screening Survey (CNSSS). We used changes in the satellite-measured impervious surfaces rate and nighttime light data to assess the level of urbanization. Every interquartile increment in the impervious surfaces rate or nighttime light was related to a decreased risk of ECG abnormalities, with odds ratios of 0.894 (95% CI, 0.869–0.920) or 0.809 (95% CI, 0.772–0.847), respectively. And we observed a U-shaped nonlinear exposure–response relationship curve between the impervious surfaces rate and ECG abnormalities. In conclusion, the current average level of urbanization among the studied Chinese adults remains a beneficial factor for reducing cardiovascular risks. [ABSTRACT FROM AUTHOR]