A Unified Approach to the Characterization of Equivalence Classes of DAGs, Chain Graphs with no Flags and Chain Graphs

Abstract.  A Markov property associates a set of conditional independencies to a graph. Two alternative Markov properties are available for chain graphs (CGs), the Lauritzen–Wermuth–Frydenberg (LWF) and the Andersson–Madigan– Perlman (AMP) Markov properties, which are different in general but coincide for the subclass of CGs with no flags . Markov equivalence induces a partition of the class of CGs into equivalence classes and every equivalence class contains a, possibly empty, subclass of CGs with no flags itself containing a, possibly empty, subclass of directed acyclic graphs (DAGs). LWF-Markov equivalence classes of CGs can be naturally characterized by means of the so-called largest CGs , whereas a graphical characterization of equivalence classes of DAGs is provided by the essential graphs . In this paper, we show the existence of largest CGs with no flags that provide a natural characterization of equivalence classes of CGs of this kind, with respect to both the LWF- and the AMP-Markov properties. We propose a procedure for the construction of the largest CGs, the largest CGs with no flags and the essential graphs, thereby providing a unified approach to the problem. As by-products we obtain a characterization of graphs that are largest CGs with no flags and an alternative characterization of graphs which are largest CGs. Furthermore, a known characterization of the essential graphs is shown to be a special case of our more general framework. The three graphical characterizations have a common structure: they use two versions of a locally verifiable graphical rule. Moreover, in case of DAGs, an immediate comparison of three characterizing graphs is possible.     

Some Notes on Workplace Equality Renewal in the Swedish Labour Market

In 2001, Swedish authorities imposed a new obligation upon all firms with ten or more employees to undertake annual wage surveys, ‘workplace equality audits’ in which it is possible to ascertain, remedy and prevent unwarranted wage differentials and other unfair employment terms between men and women. An important implication of the new system, called ‘workplace equality renewal’ (självsanering), is that, at the level of the firm all Swedish employers must explain what they mean by work of ‘equal value’ as opposed to ‘different value’. This article discusses the practical pros and cons of the new system, and considers how the surveys can be used in research into the present state of gendered work division. A main finding is that the introduction of this new legislation in the long run might change the Swedish industrial relations system as well as the preconditions for many companies’ human resource management policies. Yet, neither the governmental agencies involved nor the parties’ confederate organizations have been able to clarify what the issue is really about to the single, small business employer or to the local trade union branches. Many employers find any interference, whatever it may be, threatening and trade unions have not realized the potentialities of the system from an employee perspective, potentialities connected to the fact that companies are now more or less forced to make transparent their wage policies at large.     

论企业的联合产权制度性质

企业是一个以资源、能力与知识为基础的由要素所有者联合与劳动所有者联合相结合以创造、控制、分配 合作剩余的专业化生产性组织。联合产权制度是现代企业制度的普遍形式,也是现代企业制度的根本性质。     

What's wrong with sociology? Its public image

In response to editor Stephen Cole's question—"What's wrong with sociology?"—the answer is nothing that cannot be overcome by clearer communications and better public relations. The problem is that the field is not held in high esteem by college administrators, legislators, and the public. Many see us as rebels of the 1960s, political liberals, and impractical thinkers with a penchant for jargon. Even our research is derided by some as a waste of money. The solution consists of strategies for overcoming our poor public image. Seven strategies for doing so are discussed: (1) Write clearly. (2) Write for a mass audience. (3) Seek board positions. (4) Strengthen our identity. (5) Teach sociology in high school. (6) Develop academic partnerships. (7) Emphasize outcomes: increase in tolerance and research skills.     

Three Object Relations Models of Couple Treatment

This article describes three different approaches to the treatment of couples, all based on different versions of object relations theories. Object relations as a term has various meanings embodying different theoretical assumptions. It is used differentially to highlight certain aspects of clinical phenomena, to connote certain developmental paradigms, and to signal the importance of real, interactional aspects of human behavior. The three therapeutic approaches to work with couples illustrate some of the ways that the greater conceptual complexity of object relations theories affects how love is explained, couple conflicts defined, and what makes for change in couples treatment. Understanding the basic assumptions of a given theory will enable us to increase our informed consent to the use of theory in our practices.     

论知识产权保护水平——以国家知识产权战略为视野

基于国情考虑,中国应采取适度及动态的知识产权保护水平,并且这一选择应体现在目前正在制定的国家知识产权战略中。对知识产权保护水平的研究,既要进行定性分析,又要进行定量分析,但现有的分析方法仍有诸多缺陷。     

扬州市邗江区乡镇预防保健体制改革两种模式的比较研究

扬州市邗江区1999年对全区21所乡镇卫生院进行了产权制度改革。改制前3年,实行“医防合一”体制,从2002年起实行“医防分设”体制。文章采用定性调查和定量调查相结合的方法,比较改革前后农村卫生体系和农村预防保键资源、组织机构、服务效率、监督执法力度、农民满意度等方面的变化。研究表明,“医防分设”是必由之路,为进一步改革和完善预防保健体系提供了依据。     

清代佑宁寺在满蒙藏多边关系格局中的地位探微

17世纪的蒙藏关系发展到一个新的阶段,清朝政府采取种种措施加强对蒙藏地区的统治,被誉为“湟北诸寺之母”的青海佑宁寺,以高僧辈出、著作宏富而驰名蒙、藏、土等地区,在藏传佛教发展史上占有重要地位。佑宁寺在宗教方面的历史贡献前人已有著述,本文则试从其政治、文化等方面分析佑宁寺在密切蒙藏关系、清中央王朝对蒙藏地区的统治所起的桥梁与纽带作用进行探讨。     

It Takes Two to Fight in School,Too: A Social Relations Model of the Psychometric Properties and Relative Variance of Dyadic Aggression and Victimization in Middle School

Aggressive behavior has been well studied in terms of interindividual differences among aggressors and victims, but has been understudied, especially within naturalistic contexts, in terms of aggressor–victim relationships. The social relations model (SRM) is a powerful conceptual and analytic tool for studying dyadic phenomena, and we describe the use of multivariate SRM to study aggression. Boys and girls (N = 210) in middle schools (sixth and seventh grades) completed a newly created dyadic aggression and victimization inventory (DAVI). Results support the reliability and validity of the DAVI in assessing inter‐individual and inter‐dyadic differences in aggression and victimization. Occurrences of aggression were accounted for primarily by inter‐dyadic variability, indicating the importance of considering aggressor–victim relationships. We discuss the implications of this relationship focus for future research and intervention efforts.     

Relations among Sadness Regulation,Peer Acceptance,and Social Functioning in Early Adolescence: The Role of Gender

Using a multi‐informant approach, this study examined emotion regulation within the social context of White and Black adolescent peer groups by assessing two aspects of sadness expression management (i.e., inhibition, disinhibition) and their linkages to peer acceptance and social functioning as a function of gender and ethnicity. Seventh‐ and eighth‐grade adolescents (N = 155, 52 percent female, 54.8 percent Black) completed self‐reports and peer nominations of sadness management and sociometric ratings of peer acceptance. Parents rated their child's social competence and social problems. Results revealed specific patterns of sadness regulation across informants that were associated with social functioning and varied by gender, but not ethnicity. Boys were more likely than girls to minimize sadness displays; boys who violated this pattern had lower peer acceptance and higher parent‐rated social problems. In contrast, although girls were rated as displaying overt sadness more frequently than boys, this was unrelated to peer acceptance.