ESTIMATION OF THE CONCENTRATION PARAMETERS OF THE FISHER MATRIX DISTRIBUTION ON 50(3) AND THE BINGHAM DISTRIBUTION ON Sq, q≥ 2

Two procedures are considered for estimating the concentration parameters of the Fisher matrix distribution for rotations or orientations in three dimensions. The first is maximum likelihood. The use of a convenient 1-dimensional integral representation of the normalising constant, which greatly simplifies the computation, is suggested. The second approach exploits the equivalence of the Fisher distribution for rotations in three dimensions, and the Bingham distribution for axes in four dimensions. We describe a pseudo likelihood procedure which works for the Bingham distribution in any dimension. This alternative approach does not require numerical integration. Results on the asymptotic efficiency of the pseudo likelihood estimator relative to the maximum likelihood estimator are given, and the two estimators are compared in the analysis of a well-known vectorcardiography dataset.     

How human resource outsourcing affects organizational learning in the knowledge economy

Adaptability and knowledge management, key elements of organizational learn-ing, are critical to organizational success as a result of a fundamental shift towards a knowledge economy. HR outsourcing and the growth in contingent work can result in a significant loss in learning capital through a breakdown in the psychological contract. We explore how to preserve HR's strategic role in facilitating organizational learning in the new outsourcing and offshoring con-text. The problem is compounded if outsourcing is introduced for cost control rather than strategic refocusing reasons. We suggest that managers can posi-tively influence the relationship between outsourcing and organizational learn-ing through internal marketing tactics and enriched psychological contracts. A previous version of this paper was presented at the Administrative Sciences Association of Canada (ASAC) Annual Meeting, Toronto, Canada, June 2005.     

Overcoming Market Constraints on Pro‐Poor Agricultural Growth in Sub‐Saharan Africa

In sub‐Saharan Africa, there is fairly broad agreement that increased investment in key public goods such as roads and communications infrastructure, agricultural research and water control will be required if revitalised agricultural development is to take place. However, it has proved more difficult to reach agreement on what needs to be done to improve the performance of agricultural markets. In this article we set out an agenda for investment and policy reform in this area, providing a brief theoretical examination of the co‐ordination problems involved before examining in turn demand and supply constraints affecting smallholder farmers, and policies for price stabilisation and the co‐ordination of support services. We also argue that increased attention needs to be paid to governance issues.     

Daily Variation in Adolescents' Sleep,Activities, and Psychological Well‐Being

The daily diary method was used to examine the daily dynamics of adolescent sleep time, activities, and psychological well‐being among an ethnically diverse sample of over 750 adolescents approximately 14–15 years of age. Studying and stressful demands during the day were modestly but consistently associated with less sleep that evening. Receiving less sleep at night, in turn, was modestly but consistently related to higher levels of anxiety, depressive feelings, and fatigue during the following day. In addition, the daily variability in adolescents' sleep time was notable and just as important for the youths' average levels of daily psychological well‐being as was the average amount of time spent sleeping each night. A small number of ethnic and gender differences emerged in the dynamics of adolescent sleep, activities, and well‐being. Discussion focuses on the importance of examining variability in adolescents' sleep behaviors in order to better understand the implications of sleep for adolescent well‐being and development.     

Random effects and shrinkage estimation in capture-recapture models

We discuss the analysis of random effects in capture-recapture models, and outline Bayesian and frequentists approaches to their analysis. Under a normal model, random effects estimators derived from Bayesian or frequentist considerations have a common form as shrinkage estimators. We discuss some of the difficulties of analysing random effects using traditional methods, and argue that a Bayesian formulation provides a rigorous framework for dealing with these difficulties. In capture-recapture models, random effects may provide a parsimonious compromise between constant and completely time-dependent models for the parameters (e.g. survival probability). We consider application of random effects to band-recovery models, although the principles apply to more general situations, such as Cormack-Jolly-Seber models. We illustrate these ideas using a commonly analysed band recovery data set.     

Welfare Reform and Teenage Pregnancy,Childbirth, and School Dropout

This study estimates the effect of welfare reform on adolescent behaviors using a difference‐in‐differences approach. After defining the prereform and reform cohorts and considering the life course development of adolescent behavior by following each cohort from age 14 to age 16, we compare the welfare‐target and nontarget populations in the two cohorts. The difference‐in‐differences estimates are obtained using an event history model. Our analysis suggests that welfare reform has not reduced teenage fertility and school dropout. We find modest evidence that welfare reform is associated with higher risk of teenage births for girls in welfare families and higher risk of school dropout for girls in poor families. A combination of a difference‐in‐differences approach and a life course perspective can be a useful way to delineate the effect of societal‐level change on family phenomena.     

The deinstitutionalization of American marriage

This article argues that marriage has undergone a process of deinstitutionalization—a weakening of the social norms that define partners' behavior—over the past few decades. Examples are presented involving the increasing number and complexity of cohabiting unions and the emergence of same‐sex marriage. Two transitions in the meaning of marriage that occurred in the United States during the 20th century have created the social context for deinstitutionalization. The first transition, noted by Ernest Burgess, was from the institutional marriage to the companionate marriage. The second transition was to the individualized marriage in which the emphasis on personal choice and self‐development expanded. Although the practical importance of marriage has declined, its symbolic significance has remained high and may even have increased. It has become a marker of prestige and personal achievement. Examples of its symbolic significance are presented. The implications for the current state of marriage and its future direction are discussed.     

披头士法则

维珍集团主席理查德·布兰森以善于激励员工创造力而闻名，他坚信“乐趣”是创建企业必不可少的要素。可另一方面，不计其数的商务人士都把工作场所当成监狱，他们越来越难以在工作中找到乐趣，无法与自己周围的同事建立感情纽带，此时工作效率也会大受影响。     

How Co-operative is Co-operative Purchasing in Smaller Firms?: Evidence from UK Engineering SMEs

Most SMEs do not try to engage in co-operative purchasing arrangements, and even those that do don’t handle them very well. Examining a sample of SME engineering firms from the UK Midlands for signs of more advanced practice, the authors identify three types of behaviour: firms with deliberate strategies (where co-operative purchasing is a consciously-designed and long-term part of management policy); firms with close ties with their suppliers but which still operate fundamentally adversarial policies (where, despite some development of practice, defensive, short-term and ‘low-trust’ attitudes still predominate) and those whose strategies, maybe of long standing, ‘just happened’ and are described as still emergent. The article analyses these positions to yield lessons for managers, recognising that, as firms grow, emergent strategies will need replacing with something more codified.     

Participation or practice innovation: tensions in inter‐agency working to address disciplinary exclusion from school

This paper explores dilemmas and tensions between two models of school based inter‐agency meetings to prevent disciplinary exclusion from school. The first model is characterised by innovative practice developed through long established professional relationships and addresses both individual and strategic issues in supporting young people who are at risk of disciplinary exclusion from school. The second model strongly emphasises the right to participation of young people and their families in school based inter‐agency meetings. Research participants in three Scottish councils (parents, pupils, teachers and other professionals 1 ) had identified school based inter‐agency meetings as key to the process of inter‐agency working to prevent school exclusion.