Levees are affected by over-exploitation of river sand and river adjustments after the formation of sand pits. The slope stability is seriously threatened, drawing wide concern among experts and scholars in the area o...Levees are affected by over-exploitation of river sand and river adjustments after the formation of sand pits. The slope stability is seriously threatened, drawing wide concern among experts and scholars in the area of water conservancy. This study analyzed the uncertainties of slope stability of levees under river sand mining conditions, including uncertainty caused by interest- driven over-exploitation by sand mining contractors, and uncertainty of the distance from the slope or sand pit to the bottom of the levee under the action of cross-flow force after the sand pit forms. Based on the results of uncertainty analysis, the distribution and related parameters of these uncertainties were estimated according to the Yangtze River sand mining practice. A risk model of the slope instability of a levee under river sand mining conditions was built, and the possibility of slope instability under different slope gradients in a certain reach of the Yangtze River was calculated with the Monte Carlo method and probability combination method. The results indicated that the probability of instability risk rose from 2.38% to 4.74% as the pits came into being.展开更多
Individuals’risk attitudes play an important role in economic decision making and policy evaluation,particularly in the midst of unprecedented uncertainty caused by the COVID-19 pandemic.We adopt a multiple-price-lis...Individuals’risk attitudes play an important role in economic decision making and policy evaluation,particularly in the midst of unprecedented uncertainty caused by the COVID-19 pandemic.We adopt a multiple-price-list elicitation method with real money incentives to measure precisely individuals’risk attitudes at different stake levels and the extent to which they are affected by personal and social shocks following the COVID-19 outbreak in China.We find that subjects who had previously experienced negative personal shocks are more risk-averse at medium and large stakes but more risk loving at very small stakes.For our sample,COVID-19 has no significant impact on risk attitudes,as it is more likely to be regarded as a social shock.The result indicates that the impact of COVID-19 on individual risk attitudes is not as influential as expected,unless the individual’s personal life is affected directly.展开更多
基金supported by the Special Fund for Public Welfare Industry of the Ministry of Water Resources of China (Grant No. 201001007)
文摘Levees are affected by over-exploitation of river sand and river adjustments after the formation of sand pits. The slope stability is seriously threatened, drawing wide concern among experts and scholars in the area of water conservancy. This study analyzed the uncertainties of slope stability of levees under river sand mining conditions, including uncertainty caused by interest- driven over-exploitation by sand mining contractors, and uncertainty of the distance from the slope or sand pit to the bottom of the levee under the action of cross-flow force after the sand pit forms. Based on the results of uncertainty analysis, the distribution and related parameters of these uncertainties were estimated according to the Yangtze River sand mining practice. A risk model of the slope instability of a levee under river sand mining conditions was built, and the possibility of slope instability under different slope gradients in a certain reach of the Yangtze River was calculated with the Monte Carlo method and probability combination method. The results indicated that the probability of instability risk rose from 2.38% to 4.74% as the pits came into being.
文摘Individuals’risk attitudes play an important role in economic decision making and policy evaluation,particularly in the midst of unprecedented uncertainty caused by the COVID-19 pandemic.We adopt a multiple-price-list elicitation method with real money incentives to measure precisely individuals’risk attitudes at different stake levels and the extent to which they are affected by personal and social shocks following the COVID-19 outbreak in China.We find that subjects who had previously experienced negative personal shocks are more risk-averse at medium and large stakes but more risk loving at very small stakes.For our sample,COVID-19 has no significant impact on risk attitudes,as it is more likely to be regarded as a social shock.The result indicates that the impact of COVID-19 on individual risk attitudes is not as influential as expected,unless the individual’s personal life is affected directly.
