Asymptotic bias in the linear mixed effects model under non-ignorable missing data mechanisms

Summary.  In longitudinal studies, missingness of data is often an unavoidable problem. Estimators from the linear mixed effects model assume that missing data are missing at random. However, estimators are biased when this assumption is not met. In the paper, theoretical results for the asymptotic bias are established under non-ignorable drop-out, drop-in and other missing data patterns. The asymptotic bias is large when the drop-out subjects have only one or no observation, especially for slope-related parameters of the linear mixed effects model. In the drop-in case, intercept-related parameter estimators show substantial asymptotic bias when subjects enter late in the study. Eight other missing data patterns are considered and these produce asymptotic biases of a variety of magnitudes.     

解决我国农业剩余劳动力就业问题的思路

农业剩余劳动力的就业问题 ,是我国经济中的一个重要问题。要解决好这一问题 ,就需要制定引导农业劳动力转移的战略 ,多方寻求劳动力转移的途径 ,努力提高农业劳动力素质 ,建立健全劳动力市场 ,营造有利于农业剩余劳动力就业的制度环境 ,控制人口过快增长     

Corporate funding of the arts in a turbulent environment

Focusing on funding in culture and the arts, the author identifies a distinctive logic of company support for nonprofit organizations. Business giving is increasingly disciplined around company objectives, giving levels are driven by pretax earnings, and giving decisions are the province of managers who draw advice less from the arts community or public agencies than from other companies. At best, turbulence in government funding has modest effect on corporate support. In turn, change in corporate support has little impact on public backing. The separate logics of corporate and government support imply separate and distinctive long-term development strategies for nonprofit organizations.     

林业发展阶段研究概述

阶段性是事物发展必须遵循的一个客观规律,林业的发展同样也具有阶段性.只有充分认识各个时期林业发展所处的历史阶段和相应特征,才能更好地制定政策和发展战略.该文将以往的林业方面的阶段性研究加以综述,以期获得收益和启发,并为以后的研究打下基础.     

Reasoning With Partial Knowledge

We investigate how sociological argumentation differs from classical first–order logic. We focus on theories about age dependence of organizational mortality. The overall pattern of argument does not comply with the classical monotonicity principle: Adding premises overturns conclusions in an argument. The cause of nonmonotonicity is the need to derive conclusions from partial knowledge. We identify metaprinciples that appear to guide the observed sociological argumentation patterns, and we formalize a semantics to represent them. This semantics yields a new kind of logical consequence relation. We demonstrate that this new logic can reproduce the results of informal sociological theorizing and lead to new insights. It allows us to unify existing theory fragments, and it paves the way toward a complete classical theory.     

The 10% Flat Tax: Tithing and the Definition of Income

Developing a fair and widely accepted income definition presents one of the greatest challenges to tax reform. To arrive at a definition separate from the federal tax code, we surveyed 1200 Latter‐day Saints about their practice of tithing. Tithing is similar to a flat tax with no deductions, where individuals voluntarily contribute 10% of self‐defined income to the church. The results of our survey indicate that most respondents operate on a cash realization basis, which excludes savings and does not allow any deductions. Respondents' income concepts generally do not coincide with current tax laws or economists' views of comprehensive income.     

人居环境·古典园林·水

该文在查阅古文献的基础上 ,对我国古代在城市水资源合理利用与开发的同时 ,如何与改善人居环境、城市景观相结合进行了分析研究。古人的这种做法对于如何改善我国目前日益恶劣的城市生态环境以及如何使人居环境工程建设与城市景观建设密切结合 ,给予了很好的启示作用