On the adequacy of variational lower bound functions for likelihood-based inference in Markovian models with missing values

Summary. Variational methods have been proposed for obtaining deterministic lower bounds for log-likelihoods within missing data problems, but with little formal justification or investigation of the worth of the lower bound surfaces as tools for inference. We provide, within a general Markovian context, sufficient conditions under which estimators from the variational approximations are asymptotically equivalent to maximum likelihood estimators, and we show empirically, for the simple example of a first-order autoregressive model with missing values, that the lower bound surface can be very similar in shape to the true log-likelihood in non-asymptotic situations.     

Organic Farming,Gender, and the Labor Process*

Abstract This paper seeks to explain variations in gender participation in farm production and decision‐making through an analysis of organic farm types, sizes, and orientations. Based on both survey and case study data, the analysis shows that female farmers on vegetable farms and mixed livestock/cash crop farms are more likely to be involved in farm production and management than women on field crop farms, where mechanization and capital intensive production is much higher. The links to ideological orientations and motivations are also examined, suggesting that farmers with more conventional orientations to organic farming are also less likely to support gender equality.     

Delineating the Learning Process in Generating a Research Culture among Undergraduate Social Work Students: A Case Study of Student Participation in an Academic Conference

Conferences provide excellent opportunities for academics, HDR students and social work practitioners to network, learn and contribute to the general body of knowledge, and establish or maintain credibility, yet there is little research about the possible opportunities conferences may provide to undergraduate students. This article introduces the notion that undergraduate social work students have much to gain from participation in academic conferences, particularly for generating a research culture among students. It follows a specific case study of undergraduate students' attendance at an international conference by analysing their learning in the development of a greater appreciation of the links between social work research, theory and practice.     

Private school competition and public school teacher salaries

Teacher unions have fiercely fought public policy measures (e.g., vouchers, tuition tax credits) that might increase the proportion of students attending private schools. Yet increased competition in the educational service market should also lead to greater labor market competition, reducing any quasi-monopsony tendencies depressing teacher salaries. Using detailed data on over 600 Ohio school districts, we find that increased private school competition leads to higher salaries for public school teachers. It may be that union leaders disregard the interests of their members in trying to maximizing union size and power. An alternative interpretation is that unions sacrifice shortrun income gains for their members in order to maintain longterm economic rents associated with substantial political power.     

语篇翻译中的英汉衔接手段对比——布什9．11演讲分析

衔接是为了实现语篇的连贯,是语篇重要的组成部分。英汉两种语言有着不同的衔接手段,文章通过布什9． 11演讲与其中译本的对比研究,揭示出衔接手段在英汉语篇中不同的运用和侧重,明确翻译时应根据语言各自的特点以及语篇体裁的要求,灵活变通或转换衔接手段,从而忠实再现原文。     

The Research Potential of Testimony from Public Inquiry Websites

Policy and practice in child welfare and protection has been significantly influenced by public inquiries or commissions which follow highly publicised child tragedies. Whilst there has been considerable comment on the final reports, there has been little research on the evidence gathered for such inquiries. Large amounts of testimony are collected which are increasingly available on inquiry websites. Such evidence offers new forms of readily available data about professional practice across a wide range of topics. Suggestions are made about research methods and search functions, and links to some sites provided. However, the data must be understood in the context in which it was produced.     

From the Editor

Sociological Forum -