新农村建设过程中农村剩余劳动力有效转移的途径和对策

农民收入增长缓慢的问题,可从资源禀赋、市场供求关系和产业结构变化等方面进行分析,而农村劳动力就业不充分则是其中的根本原因。我们可以在对制约着农村剩余劳动力顺利转移的因素进行全面研究的基础上,提供有效转移的途径,并改善其配套对策。     

Calibrated path sampling and stepwise bridge sampling

A computational problem in many fields is to evaluate multiple integrals and expectations simultaneously. Consider probability distributions with unnormalized density functions indexed by parameters on a 2-dimensional grid, and assume that samples are simulated from distributions on a subgrid. Examples of such unnormalized density functions include the observed-data likelihoods in the presence of missing data and the prior times the likelihood in Bayesian inference. There are various methods using a single sample only or multiple samples jointly to compute each integral. Path sampling seems a compromise, using samples along a 1-dimensional path to compute each integral. However, different choices of the path lead to different estimators, which should ideally be identical. We propose calibrated estimators by the method of control variates to exploit such constraints for variance reduction. We also propose biquadratic interpolation to approximate integrals with parameters outside the subgrid, consistently with the calibrated estimators on the subgrid. These methods can be extended to compute differences of expectations through an auxiliary identity for path sampling. Furthermore, we develop stepwise bridge-sampling methods in parallel but complementary to path sampling. In three simulation studies, the proposed methods lead to substantially reduced mean squared errors compared with existing methods.     

中华民族共同体意识:研究概貌与未来展望

民族意识自觉、民族文化共生、马克思主义民族理论影响、我国民族理论创新是中华民族共同体意识形成的主要思想渊源;认同范畴、意识范畴、要素范畴是解读中华民族共同体意识本质内涵的三个维度;扎实做好民族工作、维护国家统一、推动中华民族伟大复兴、助推中华民族共同体与人类命运共同体建设是铸牢中华民族共同体意识的核心价值意蕴;增强"五个认同"、推动各民族交往交流交融、强化制度建设、增强文化教育、拓宽传播媒介是铸牢中华民族共同体意识的主要实践路径。本领域未来研究可重点关注铸牢中华民族共同体意识的理论体系构建、量化实证研究、多学科视角分析及心理机制探索。