On the extrapolation to ITER of discharges in present tokamaks

An expression for the extrapolated fusion gain G = Pfusion /5 Pheat (Pfusion being the total fusion power and Pheat the total heating power) of ITER in terms of the confinement improvement factor (H) and the normalised beta (betaN) is derived in this paper. It is shown that an increase in normalised beta can be expected to have a negative or neutral influence on G depending on the chosen confinement scaling law. Figures of merit like H betaN / q95^2 should be used with care, since large values of this quantity do not guarantee high values of G, and might not be attainable with the heating power installed on ITER.Comment: 6 Pages, 3 figures, Submitted to Nuclear Fusion on the 29th of November 200

Compensation dispersion between and within hierarchical levels

This paper studies the dispersion around the expected compensation of workers before and after controlling for hierarchical positions in cross-section data samples. From data for Spanish managers, we find that this dispersion decreases with education and work experience before entering the current job and increases with job tenure. This finding contrasts with previous research that finds a positive association between compensation dispersion and education and work experience. We explain the new finding through a model of learning that separates compensation dispersion between jobs and within jobs (hierarchical positions). The model takes advantage of the information revealed when workers are promoted to their current hierarchical positions and allows for more robust tests of learning theories

Three Retirement Decision Models for Defined Contribution Pension Plan Members: A Simulation Study

This paper examines the hypothetical retirement behavior of defined contribution (DC) pension plan participants. Using a Monte Carlo simulation approach, we compare and discuss three retirement decision models: the two-thirds replacement ratio benchmark model, the optionvalue of continued work model and a newly-developed “one-year ” retirement decision model. Unlike defined benefit (DB) pension plans where economic incentives create spikes in retirement at particular ages, all three retirement decision models suggest that the retirement ages of DC participants are much more smoothly distributed over a wide range of ages. We find that the one-year model possesses several advantages over the other two models when representing the theoretical retirement choice of a DC pension plan participant. First, its underlying theory for retirement decision-making is more feasible given the distinct features and pension drivers of a DC plan. Second, its specifications produce a more logical relationship between an individual’s decision to retire and his/her age and accumulated retirement wealth. Lastly, although the one-year model is less complex than the option-value model as the DC participants ’ scope is only one year, the retirement decision is optimal over all future projected years if projections are made using reasonable financial assumptions

Young offenders' experiences of traumatic life events. A qualitative investigation

This investigation aimed to look at how a group of young offenders attending an inner-city youth offending team experienced adverse and traumatic life events. A qualitative approach was used and semi-structured interviews were conducted with eight young offenders about their perceptions of difficult experiences and the effects of such events. The interviews were analysed using Interpretative Phenomenological Analysis (Smith, Jarman, & Osborn, 1999). Analysis of the accounts yielded a number of themes. Young offenders experienced violence at home, in the community and in custody. Instability and transitions emerged as important themes in relation to school and home. Deprivation was experienced both in terms of poverty and the literal and emotional absence of parents. A variety of cognitive, emotional and behavioural responses to adverse/traumatic experiences were identified, including a blocking out of painful experience and aggression to self and others. There were barriers to seeking or making use of professional support. Custody appeared to offer an opportunity to reflect on and re-evaluate life trajectory. The study concluded that greater consideration of trauma when carrying out assessments would enable `at risk' young offenders to be identified using clinical interviewing along side standardized measures to aid assessment of the complexity and uniqueness of the response to trauma