An invitation to quantum tomography

Summary.  We describe quantum tomography as an inverse statistical problem in which the quantum state of a light beam is the unknown parameter and the data are given by results of measurements performed on identical quantum systems. The state can be represented as an infinite dimensional density matrix or equivalently as a density on the plane called the Wigner function. We present consistency results for pattern function projection estimators and for sieve maximum likelihood estimators for both the density matrix of the quantum state and its Wigner function. We illustrate the performance of the estimators on simulated data. An EM algorithm is proposed for practical implementation. There remain many open problems, e.g. rates of convergence, adaptation and studying other estimators; a main purpose of the paper is to bring these to the attention of the statistical community.     

The Quest for Aid Complementarity: Reforming Co‐operation between Nordic+ Donors and NGOs

Aid fragmentation is a maddening problem in the aid business. NGOs are part and parcel of this fragmentation problem; hence calls for more complementarity between Northern NGOs and (their) governments have led to a series of co‐funding reforms. This article analyses the co‐funding reforms of the Nordic+ donors and situates them within the broader evolutions that have taken place in donor‐NGO relations in these countries. It finds that these donors have interpreted complementarity in very different and even contradictory ways. Where some require NGOs to develop activities within the confines of the official bilateral strategy (intensive complementarity), others allow NGOs to do very different things (extensive complementarity).     

Domestic violence and child abuse: developing sensitive policies and guidance

Domestic violence is everywhere and nowhere. No statutory organization or health service has work with either perpetrators or survivors of domestic violence (usually women and children) as the primary focus of their service, yet all agencies will have very significant numbers among their clients/service users. It is therefore crucial that the policy framework is developed both within and between agencies to address the need, and scope, of intervention in this area and particularly the impact on children. Currently, significant steps have been taken by some agencies in the UK to address this previously neglected issue, though the developments are patchy. This paper draws on a UK‐wide research study which mapped the extent and range of service provision for families where there is domestic violence and also developed a framework of good practice indicators for provision in this area. This article examines one of the indicators of good practice arising from the research—that of policy development—within social service departments and within the multi‐agency arena. Copyright © 2001 John Wiley & Sons, Ltd.     

Giving a Voice to Women Survivors of Domestic Violence through Recognition as a Service User Group

Perhaps surprisingly, given the germinal role played by thewomen’s movement, women survivors of domestic violenceare not amongst those commonly conceptualized as service usergroups. This paper explores why this may be the case and whyit matters. It draws upon the findings of a multi-methodologicalstudy of specialist domestic violence services and of relateduser and professional views. It demonstrates the limitationsto survivors’ influence within these services, some ofthe key obstacles women experience, and the commonalities anddifferences between these and the experiences of other usergroups. In particular, the specific issues of women still ‘beingin the experience’ and of professionals who are also survivorsbut who feel unable to disclose this are discussed as usefulcontributions to the theory of service user involvement.     

A Stylometric Analysis of King Alfred's Literary Works

For centuries, Alfred the Great was judged to have translated several Latin texts into Old English. Many scholars, however, have expressed doubt whether Alfred could have done all of this work. With the availability of the Old English Corpus in electronic form, it is feasible to subject the texts to statistical stylometric analysis. We approach the problem from a Bayesian perspective where key words are identified and frequencies of the key words are tabulated for seven relevant texts. The question of authorship falls into the general statistical problem of classification where several simple innovations to classical agglomerative procedures are introduced. Our results suggest that one translation that has been traditionally attributed to Alfred (The First Fifty Prose Psalms) tends to distinguish itself from texts that are known to be Alfredian.     

Normative collective behavior in the Station building fire

Objective. This article offers a test of the normative explanation of collective behavior by examining the fire at the Station nightclub in Rhode Island that killed 100 and injured nearly 200 persons.Methods. Information on all persons at the club comes from content analysis of documents from the Rhode Island Police Department, the Rhode Island Office of the Attorney General, and The Providence Journal. We use negative binomial regression to test hypotheses about the effects of group-level predictors of the counts of dead and injured in 179 groups at the nightclub.Results. Results indicate that group-level factors such as distance of group members at the start of the fire, the number of intimate relations among them, the extent to which they had visited the nightclub prior to the incident, and the average length of the evacuation route they used predict counts of injured and dead. The research also looks at what behavioral differences exist between survivors and victims, ascertains the existence of role extension among employees of the nightclub, and provides support for the affirmation that dangerous contexts negate the protective influence of intimate relations in groups.Conclusion. We argue for the abandonment of current emphasis on irrationality and herd-like imitative behavior in studies of evacuation from structural fires in buildings and for the inclusion of group-level processes in social psychological explanations of these incidents.     

Mobility and Nunavut Inuit youth: lessons from Northern Youth Abroad

In this paper we examine the impacts of the mobility that Nunavut Inuit youth experience with Northern Youth Abroad (NYA), a Canadian volunteer travel program that sends northern youth to southern Canada and Botswana. Using a case study approach and drawing from archival research and interviews with 10 former participants, a staff member, and a member of the board of directors, we argue that NYA illustrates how volunteer travel programs for Indigenous youth can yield distinct benefits for its participants in comparison to mainstream volunteer travel programs, particularly with regard to participants' sense of cultural identity and pride. By enabling participants to foster career goals and a deeper sense of cultural pride, NYA presents a counter-example to some of the common critiques of volunteer tourism programs, and illustrates the complex interconnections between cultural pride, well-being, and career advancement for Nunavut Inuit youth.     

Does Intergenerational Educational Mobility Shape the Well-Being of Young Europeans? Evidence from the European Social Survey

The level of accessibility to basic services is an important issue because it is closely related to social inclusion and social capital, key aspects of societal well-being. There is a large and growing literature on access to health care in an era of dwindling public resources due to recent economic downturns. Health care is an essential service, but it is not the only basic service. The literature on access to basic services including, but not limited to, health care is relatively small. The paper aims at contributing to the literature by providing a new index to measure and monitor household accessibility to basic services. A study of Italian regions is presented. It is shown that northern regions have more accessible basic services than central, southern and island regions. A longitudinal comparison has been performed. The results are very worrying because show that policy makers have failed in reducing regional (and in particular north–south) disparities in basic service accessibility. Measuring and monitoring the level of accessibility is central for an adequate provision of basic services and for exploring how the delivery of basic services in the most problematic regions can be improved.     

A SEMIPARAMETRIC BAYESIAN APPROACH TO NETWORK MODELLING USING DIRICHLET PROCESS PRIOR DISTRIBUTIONS

This paper considers the use of Dirichlet process prior distributions in the statistical analysis of network data. Dirichlet process prior distributions have the advantages of avoiding the parametric specifications for distributions, which are rarely known, and of facilitating a clustering effect, which is often applicable to network nodes. The approach is highlighted for two network models and is conveniently implemented using WinBUGS software.