A new solver based on the high-resolution scheme with novel treatments of source terms and interface capture for the Savage-Hutter model is developed to simulate granular avalanche flows. The capability to simulate fl...A new solver based on the high-resolution scheme with novel treatments of source terms and interface capture for the Savage-Hutter model is developed to simulate granular avalanche flows. The capability to simulate flow spread and deposit processes is verified through indoor experiments of a two-dimensional granular avalanche. Parameter studies show that reduction in bed friction enhances runout efficiency, and that lower earth pressure restraints enlarge the deposit spread. The April 9, 2000,Yigong avalanche in Tibet, China, is simulated as a case study by this new solver. The predicted results, including evolution process, deposit spread, and hazard impacts, generally agree with site observations. It is concluded that the new solver for the Savage-Hutter equation provides a comprehensive software platform for granular avalanche simulation at both experimental and field scales. In particular, the solver can be a valuable tool for providing necessary information for hazard forecasts, disaster mitigation, and countermeasure decisions in mountainous areas.展开更多
Objective:To explore the performance of a protocol combining fecal immunochemical test(FIT)and a high-risk factor questionnaire(HRFQ)for selecting patients requiring colonoscopy as part of a population-based colorecta...Objective:To explore the performance of a protocol combining fecal immunochemical test(FIT)and a high-risk factor questionnaire(HRFQ)for selecting patients requiring colonoscopy as part of a population-based colorectal cancer(CRC)screening program in China.Methods:From 2015 to 2016,we conducted a CRC screening program for all residents aged 45 years or older in Tianhe District,Guangzhou City,China.Participants underwent an FIT and received an HRFQ as part of primary screening.Those with positive FIT and/or HRFQ results were considered to be at high risk and were recommended to undergo colonoscopy.Results:A total of 10074 subjects were recruited and enrolled in the screening program.In the enrolled population,17.5%had positive FIT results and 19.4%had positive HRFQ results.Of those recommended to undergo diagnostic colonoscopy,773 did so.The screening method’s overall positive predictive value(PPV)was 4.9%for non-adenomatous polyps,11.4%for low-risk adenomas(LRAs),15.9%for high-risk adenomas(HRAs)and 1.6%for CRC.The PPVs of positive FIT results for nonadenomatous polyps,LRAs,HRAs and CRC were 5.2%,15.9%,22.5%and 2.5%,respectively.The PPVs of positive HRFQ results for non-adenomatous polyps,LRA,HRA and CRC were 4.1%,10.2%,14.3%and 1.4%,respectively.The PPVs associated with combined positive FIT and HRFQ results for non-adenomatous polyps,LRAs,HRAs and CRC were 4.5%,16.4%,23.7%and 2.8%,respectively.Conclusion:Our results suggest that this two-step CRC screening strategy,involving a combination of FIT and HRFQ followed by colonoscopy,is useful to identify early-stage CRC.The high detection rates and PPVs for CRC and adenomas encourage this strategy’s use in ongoing screening programs.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11602278,and 11432015)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB22040203)the LMFS Foundation for Young Scientists
文摘A new solver based on the high-resolution scheme with novel treatments of source terms and interface capture for the Savage-Hutter model is developed to simulate granular avalanche flows. The capability to simulate flow spread and deposit processes is verified through indoor experiments of a two-dimensional granular avalanche. Parameter studies show that reduction in bed friction enhances runout efficiency, and that lower earth pressure restraints enlarge the deposit spread. The April 9, 2000,Yigong avalanche in Tibet, China, is simulated as a case study by this new solver. The predicted results, including evolution process, deposit spread, and hazard impacts, generally agree with site observations. It is concluded that the new solver for the Savage-Hutter equation provides a comprehensive software platform for granular avalanche simulation at both experimental and field scales. In particular, the solver can be a valuable tool for providing necessary information for hazard forecasts, disaster mitigation, and countermeasure decisions in mountainous areas.
基金supported by Guangzhou Science and Technology Plan Projects(Health Medical Collaborative Innovation Program of Guangzhougrant No 201400000001-4)Science and Technology Planning Project of Guangdong Province(No 2013B0218001462).
文摘Objective:To explore the performance of a protocol combining fecal immunochemical test(FIT)and a high-risk factor questionnaire(HRFQ)for selecting patients requiring colonoscopy as part of a population-based colorectal cancer(CRC)screening program in China.Methods:From 2015 to 2016,we conducted a CRC screening program for all residents aged 45 years or older in Tianhe District,Guangzhou City,China.Participants underwent an FIT and received an HRFQ as part of primary screening.Those with positive FIT and/or HRFQ results were considered to be at high risk and were recommended to undergo colonoscopy.Results:A total of 10074 subjects were recruited and enrolled in the screening program.In the enrolled population,17.5%had positive FIT results and 19.4%had positive HRFQ results.Of those recommended to undergo diagnostic colonoscopy,773 did so.The screening method’s overall positive predictive value(PPV)was 4.9%for non-adenomatous polyps,11.4%for low-risk adenomas(LRAs),15.9%for high-risk adenomas(HRAs)and 1.6%for CRC.The PPVs of positive FIT results for nonadenomatous polyps,LRAs,HRAs and CRC were 5.2%,15.9%,22.5%and 2.5%,respectively.The PPVs of positive HRFQ results for non-adenomatous polyps,LRA,HRA and CRC were 4.1%,10.2%,14.3%and 1.4%,respectively.The PPVs associated with combined positive FIT and HRFQ results for non-adenomatous polyps,LRAs,HRAs and CRC were 4.5%,16.4%,23.7%and 2.8%,respectively.Conclusion:Our results suggest that this two-step CRC screening strategy,involving a combination of FIT and HRFQ followed by colonoscopy,is useful to identify early-stage CRC.The high detection rates and PPVs for CRC and adenomas encourage this strategy’s use in ongoing screening programs.
