In an influential article, [Romer, C. “The Great Crash and the Onset of the Great Depression,” Quarterly Journal of Economics, 105, 1990, pp. 597–624.] estimates the magnitudes of the uncertainty and wealth effects. She reports that before and after the Great Depression, the uncertainty...

Taking land circulation of Hebei Province, China as an example, circulation status of rural land contract and operation rights of Hebei Province is introduced. Then, sampling survey method is used to investigate the supply and demand situation of social security of 350 peasant households in...