平稳性检验方法的有效性研究

平稳性检验是时间序列分析的重要研究内容,现有检验方法的性能缺乏系统的比较分析。文章从样本长度的视角研究平稳性检验方法的性能,采用ADF检验、PP检验、KPSS检验和LMC检验四种方法展开实证研究。仿真实验结果表明:时间序列数据长度会对检验方法的准确率产生明显的影响,数据长度较小时检验准确率偏低;数据长度增大时可以提升检验方法的准确率,但仍未能达到100%的上限值。当样本长度较小时,这些方法的检验统计量的渐进分布难以满足,因此其实际检验效果值得探究。样本长度是有限的,因此渐进分布检验方式的改进空间有限,新的检验方式值得探究。     

农地信托中信托财产性质及归属谜题:困局与出路

农地信托中信托财产的性质为何,农地信托设定后信托财产所有权是否发生变动,已困扰我国学界多年.目前既有的承包权—权利转移说、承包权—权利不转移说、租赁权—权利转移说等多种学说均未能完美解决农地信托的理论谜题.农地"三权分置"政策的提出,为解决上述谜题提供了新的机遇.将农地信托中信托财产界定为农地经营权,并将这项权利配置为"高度物权化的债权",有利于彻底解决农地信托的理论谜题.     

户籍样、田令和“均田制”

北魏太和九年颁布的所谓"均田"令,是人口土地登记法。其后,修订成一种带有赋税品式色彩的户籍样式———"丘井之式"。北魏在以"六镇"为中心的西北边疆地区实行过垦田,颁布过垦田法,它也是这一地区"府户"的户籍样,后来增添进了"丘井之式"。北齐继承了户籍样制度,把北魏两种户籍样混合为一,并把规定当作土地登记和管理法归入《田令》。隋、唐沿袭北齐之制。治史者不了解源自"品式"的户籍样制度,不了解北魏有两种户籍样,把"均田"误解为均分土地,制造了"均田制"这一错误的概念。     

Perceived discrimination,traditional practices,and depressive symptoms among American Indians in the upper midwest

American Indian adults are thought to experience significant depressive symptoms at rates several times higher than adults in the general population, yet we know very little about factors associated with depressive symptoms among this under studied group. Many researchers have argued that depressive symptoms are associated with conflicts between American Indian traditional cultural values, practices, and beliefs and those of the majority culture. This report, based on a sample 287 American Indian adults from the upper Midwest, takes into account two measures of cultural effects: perceived discrimination, as one indicator of culture conflict, and traditional practices, as a measure of cultural identification. The results indicate that discrimination is strongly associated with depressive symptoms among American Indian adults and that engaging in traditional practices is negatively related to depressive symptoms. Moreover, interaction effects between perceived discrimination and traditional practices indicate that engaging in traditional practices buffers the negative effects of discrimination among those who regularly participate in them.     

Challenging the one-size-fits-all myth: findings and solutions from a statewide focus group of rural social workers

Of America's counties, 76% are rural, comprising 83% of U.S. land and 25% of the American population. Yet most child welfare programs are designed to fit the needs of urban and suburban families. This article reviews the unique needs and assets of rural children and families in Texas. It presents recommendations from a focus group for overcoming the inappropriate transfer of urban models to rural communities.     

Married women's retirement behavior

In this paper we examine the economic and family determinants of married women's retirement behavior. A life cycle model of wives' retirement decisions is tested empirically using data on working married women from the Longitudinal Retirement History Survey. This exploratory analysis indicates that family considerations are more important in wives' retirement decisions than own economic opportunities. These findings contrast with those obtained previously for male workers and if substantiated by other research could have important implications for policy questions regarding pension and Social Security reform.This research was funded by the 1986–7 Small Grants Program sponsored by the University of Wisconsin, Madison, Institute for Research on Poverty, the Cornell Institute of Social and Economic Research, and the New York State School of Industrial and Labor Relations. Excellent programming assistance was provided by Vivian Fields. We are grateful to Glen Cain and two anonymous referees for useful comments. Any opinions expressed herein are those of the authors and not those of the above-named persons or institutions.     

工业微生物学课程思政实践与思政元素挖掘

工业微生物学是生物化工系列专业的专业基础必修课程,在工业微生物学教学改革中贯穿课程思政教育,对于实现我校"五有三能"的育人目标具有重要的意义.该文结合工业微生物学教学实践,介绍了提高专任教师课程思政能力的途径,探索了课程思政的路径和方法,并挖掘了本课程的思政元素,介绍了本课程部分课程思政案例,以期为其他相关课程的课程思政提供参考.     

地理集聚会促进企业间商业信用吗?

地理集聚对经济绩效的重要影响已经被大量研究所证实,但系统考察地理集聚对企业商业信用影响的研究仍比较匮乏。本文首先在Long和Zhang(2011)基础上构造了一个更为综合的地理集聚指标,并结合1998～2007年中国工业企业数据以及"双重差分"方法,系统地探讨了地理集聚对企业商业信用的影响。研究证实,地理集聚对企业商业信用的发展具有显著的促进作用,而且资本集聚的影响超过了产出集聚和劳动集聚。此外,文章还发现,地理集聚对商业信用的影响存在显著的企业异质性:非国有企业、大企业、高效率企业以及资本密集型企业受地理集聚的影响更大。     

Quantifying the Hurricane Catastrophe Risk to Offshore Wind Power

The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. We present a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes. Using this method, we estimate the fraction of offshore wind power simultaneously offline and the cumulative damage in a region. In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously because of hurricane damage with a 100‐year return period and 6% could be destroyed in any 10‐year period. We also estimate the risks to single wind farms in four representative locations; we find the risks are significant but lower than those estimated in previously published results. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk.     

零部件循环取货越库物流系统关键因子研究——仿真实验设计与分析方法

汽车和物流产业是国家重点扶持的两大振兴产业． 在众多汽车制造企业产能扩大的背景下,以零部件平均物流时间(cycle time,CT) 为绩效评价指标,深入研究了基于第三方物流的零部件循环取货越库物流模式( 简称 3PL－MRCD) 的优化设计问题． 建立了符合企业实际运作的离散系统随机仿真模型,即零部件循环取货与越库内部运作的集成模型． 与现有供应链仿真模型相比,由于存在较多的仿真因子,提出首先运用序贯分支法( sequential bifurcation, SB) 筛选 3PL－MRCD 系统关键因子,再应用响应面法(response surface methodology,RSM) 找到关键因子最优运作水平的方法步骤( SB－RSM) ,解决了大型仿真系统的优化设计问题． 基于调研的数据进行仿真实验,结果表明 SB－RSM 可准确找出影响CT的关键因子最优取值, 该值使CT达到较为理想的水平． 对大型仿真系统的优化而言,SB － RSM 比传统 RSM 更具实 验效率与效力,SB－RSM 为产能扩大3PL 物流决策的制定提供了可靠的解决方案,具有良好的应用价值．