Probabilistic allocation rules and single-dipped preferences

We consider the problem of allocating an infinitely divisible endowment among a group of agents with single-dipped preferences. A probabilistic allocation rule assigns a probability distribution over the set of possible allocations to every preference profile. We discuss characterizations of the classes of Pareto-optimal and strategy-proof probabilistic rules which satisfy in addition replacement-domination or no-envy. Interestingly, these results also apply to problems of allocating finitely many identical indivisible objects – to probabilistic and to deterministic allocation. Received: 23 November 1998/Accepted: 20 October 2000     

'Doing Motherhood': some experiences of mothers with physical disabilities

In this paper, we discuss the experiences of physically disabled mothers. We interviewed 30 women in the age group 28-49 with medical diagnoses such as: multiple sclerosis, neuromuscular diseases, cerebral palsy and spinal cord injury Becoming a mother implied for many 'capturing' a gender or 'recapturing' a lost gender. They women felt they had to go to great lengths to 'present' themselves and their children as managing 'normally' in order to be accepted as 'ordinary' mothers. Eventually, they feared that their children might be taken away from them if they did not live up to other people's expectations. One possible explanation for what they experienced as other people's scepticism might be that disabled people on the whole are primarily still looked upon as being dependent on other people's help and care. In short, they are often looked upon by professionals and lay people as receivers, and not as carers.     

the Impact of Personality and Social Support on Mental Health for Female Patients with Rheumatoid Arthritis

The relationship between personality traits, social support and mental health problems was studied in 138 female patients with rheumatoid arthritis (RA). Structural equation modelling showed that instrumental support was uncorrelated with mental health problems. The effect of emotional support on mental health was spurious and due to personality traits. Companionship had a direct effect on mental health in addition to partially mediating the effects of both extra-version and neuroticism. However, the total effect of social support was moderate compared to a strong influence of neuroticism. The therapeutical implications are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Knowledge transfer and R&D in pharmaceutical companies: A case study

This paper analyzes the consequences for the knowledge transfer and the organization of R&D of pharmaceutical companies after the acquisition of biotech companies. Based on four in-depth case studies, this paper comes to the conclusion that there is no systematic biotechnological know-how transfer from the biotech to the pharmaceutical company after the acquisition. Instead, the biotech companies remain independent and take over the role of centers of excellence for R&D within the pharmaceutical companies because that is the only way of preserving the innovative capabilities of the biotech company.     

STENO:an expert system for medical diagnosis based on graphical models and model search

Causal probabilistic models have been suggested for representing diagnostic knowledge in expert systems. This paper describes the theoretical basis for and the implementation of an expert system based on causal probabilistic networks. The system includes model search for building the knowledge base, a shell for making the knowledge base available for users in consultation sessions, and a user interface. The system contains facilities for storing knowledge and propagating new knowledge, and mechanisms for building the knowledge base by semi-automated analysis of a large sparse contingency table. The contingency table contains data acquired for patients in the same diagnostic category as the intended application area of the expert system. The knowledge base of the expert system is created by combining expert knowledge and a statistical model search in a model conversion scheme based on a theory developed by Lauritzen & Spiegelhalter and using exact tests as suggested by Kreiner. The system is implemented on a PC and has been used to simulate the diagnostic value of additional clinical information for coronary artery disease patients under consideration for being referred to coronary arteriography.     

Psychological Weil-Being Among Unemployed and Employed People After a Company Closedown: A Longitudinal Study

In a three-year longitudinal study, we examined the effects of unemployment and the fear of becoming unemployed on the psychological well-being of 1153 employees at a shipyard that was closed down, and a control group of 441 employees from another, operative shipyard. On all three questionnaires, unemployed people were significantly lower in psychological well-being than employed people. Change to or from employment was significantly associated with changes in psychological well-being, whereas remaining employed or unemployed did not lead to any systematic changes in psychological well-being. Among employed people, the fear of unemployment was strongly associated with reduced psychological well-being. Thus, the health-related consequences of unemployment affect not only the unemployed but also employed people who have little job security. Consequently, we stress the need to create new workplaces and to implement reforms that can reduce job insecurity in the labor market.     

Mixing of MCMC algorithms

We analyse MCMC chains focusing on how to find simulation parameters that give good mixing for discrete time, Harris ergodic Markov chains on a general state space X having invariant distribution π. The analysis uses an upper bound for the variance of the probability estimate. For each simulation parameter set, the bound is estimated from an MCMC chain using recurrence intervals. Recurrence intervals are a generalization of recurrence periods for discrete Markov chains. It is easy to compare the mixing properties for different simulation parameters. The paper gives general advice on how to improve the mixing of the MCMC chains and a new methodology for how to find an optimal acceptance rate for the Metropolis-Hastings algorithm. Several examples, both toy examples and large complex ones, illustrate how to apply the methodology in practice. We find that the optimal acceptance rate is smaller than the general recommendation in the literature in some of these examples.