土地流转对农户生产社会化服务需求的影响——基于PSM模型的实证分析

土地流转背景下提高农业生产社会化服务供给效率,满足农户生产社会化服务需求对于实施乡村振兴战略具有重要意义。本文基于陕甘宁黄土高原区973户农户数据,从基础设施服务、农资供应服务、技术管理服务、加工销售服务、金融保险服务5个方面刻画农业生产社会化服务,并采用倾向得分匹配法（PSM）探讨了土地流转对农户生产社会化服务需求的影响。研究发现：① 土地流转使得农户生产社会化服务需求呈现出明显的异质性,这种总体效应主要由土地转入带来的规模效应贡献;② 土地流转对基础设施服务、技术管理服务、加工销售服务、金融保险服务具有显著的促进作用,农户需求强度分别提高0.215、0.070、0.094和0.162;土地流转对农资供应服务具有显著的抑制作用,抑制强度为0.306;③ 土地转入对农户生产社会化服务需求的影响方向与土地流转影响的总体方向一致,且影响强度大于总体强度;但土地转出与土地流转影响的总体方向差异较大,且影响强度小于总体强度。提出减少政府供给农资供应服务、加强农业技术推广力量、拓充社会化服务内容等政策建议,以此提高农业生产社会化服务供给水平,促进小农户与现代农业有序衔接。     

lP2∪T(1,1,n)的伴随等价图类

利用伴随多项式的最小实数根的性质完整刻画了lP2∪T(1,1,n)(n≥1)的伴随等价图类.     

“论康德的”意志就是实践理性

"意志就是实践理性"表达了意志与理性在超验立法层面的等同,也即纯粹意志与纯粹实践理性的等同。这种等同使人的纯粹意志成为规范性法则的来源,进而表明了道德规范的自因性和自律性。纯粹意志自律的过程是规范性法则生成的过程,同时这一过程也可看作纯粹意志的超越性力量在规范性法则上的凝结和确认,换言之,人的内生性的自由力量外化和呈现为道德性的规范法则,进言之,自律概念内部实现着超越性与规范性的转化与统一。康德把纯粹意志作为一种超验的规范意志的做法,使其哲学呈现出浓厚的意志主义色彩,这直接影响了叔本华的意志主义哲学。     

Effects of multimedia on psychometric characteristics of cognitive tests: A comparison between technology-based and paper-based modalities

The study aims to investigate the effects of delivery modalities on psychometric characteristics and student performance on cognitive tests. A first study assessed the inductive reasoning ability of 715 students under the supervision of teachers. A second study examined 731 students’ performance on the application of the control-of-variables strategy in basic physics but without teacher supervision due to the COVID-19 pandemic. Rasch measurement showed that the online format fitted to the data better in the unidimensional model across two conditions. Under teacher supervision, paper-based testing was better than online testing in terms of reliability and total scores, but contradictory findings were found in turn without teacher supervision. Although measurement invariance was confirmed between two versions at item level, the differential bundle functioning analysis supported the online groups on the item bundles constructed of figure-related materials. Response time was also discussed as an advantage of technology-based assessment for test development.