Diagnostic systems in DEMO: engineering design issues

The diagnostic systems of DEMO that are mounted on or near the torus, whether intended for the monitoring and control functions of the engineering aspects or the physics behaviour of the machine, will have to be designed to suit the hostile nuclear environment. This will be necessary not just for their survival and correct functioning but also to satisfy the pertinent regulatory bodies, especially where any of them relate to machine protection or the prevention or mitigation of accidents foreseen in the safety case. This paper aims to indicate the more important of the reactor design considerations that are likely to apply to diagnostics for DEMO, drawn from experience on JET, the provisions in hand for ITER and modelling results for the wall erosion and neutron damage effects in DEMO.Comment: 8 page

Market-Indexed Executive Compensation: Strictly for the Young

Academics have long argued that incentive contracts for executives should be indexed to remove the influence of exogenous market factors. Little evidence has been found that firms engage in such practices, also termed "relative performance evaluation". We argue that firms may not gainmuch by removing market risks from executive compensation because (i) the market provides compensation for bearing systematic risk via the market risk premium and therefore the executive desires positive exposure to such risks, and (ii) the executive can, in principle, adjust her personal portfolio to o.set any unwanted market risk imposed by her compensation contract. A testable implication is that stock-based performance incentives will be weaker when idiosyncratic risks are large but that market risks will have little e.ect. The data tend to support this hypothesis. In the full sample of CEO compensation from ExecuComp, stock-based incentives are strictly decreasing in firm-specific risk. Market-specific risks, however, are insignificantly related to incentives. The story changes somewhat when we distinguish between younger and older CEOs. Our theory is arguably less applicable to younger CEOs who have more non-tradeable exposure to systematic risk through their human capital. Consistent with this argument, we find that market risks have a negative e.ect on stock-based incentive pay for younger CEOs, while they don’t for older CEOs. This in turn implies that the traditional argument for indexation is indeed valid for younger CEOs, and we find some evidence in favor of this proposition. Specifically, we find evidence of indexation for younger but not for older CEOs. Even for younger CEOs, however, the e.ect is far too weak to remove the e.ects of market risk. This is consistent with our finding that market risk reduces pay-performance for young CEOs, but leaves the question of why there is not more indexing for such executives.

Asymmetric Benchmarking in Compensation: Executives are Paid for (Good) Luck But Not Punished for Bad

Principal-agent theory suggests that a manager should be paid relative to a benchmark that captures the effect of market or sector performance on the firm's own performance. Recently, it has been argued that we do not observe such indexation in the data because executives can set pay in their own interests, that is, they can enjoy "pay for luck" as well as "pay for performance". We first show that this argument is flawed. The positive expected return on stock markets reflects compensation for bearing systematic risk. If executives' pay is tied to market movements, they can only expect to receive the market-determined return for risk-bearing. We then reformulate the argument in a more appropriate fashion. If managers can truly influence the nature of their pay, they will seek to have their pay benchmarked only when it is in their interest, namely when the benchmark has fallen. Using a variety of market and industry benchmarks, we find that there is essentially no indexation when the benchmark return is up, but uncover substantial indexation when the benchmark has turned downwards. These empirical results are robust to a variety of alternative hypotheses and robustness checks, and suggest an increase in expected direct compensation of approximately $75,000 for the median executive in our sample, or about 5% of total compensation.

Do Stock Prices Incorporate the Potential Dilution of Employee Stock Options?

Employee stock options represent a significant potential source of dilution for many shareholders. It is well known that reported earnings tend to understate the associated costs, but an efficient stock market will show no such bias. If by contrast stock prices underestimate the future costs implied by stock option grants, option exercises will produce negative abnormal returns. We design and implement a stock-picking rule based on predictions of stock-option exercise using widely available data. The rule identifies stocks that subsequently suffer significnt negative abnormal returns using either a CAPM or the three factor Fama-French benchmarks. According to our point estimates, if the cost of employee stock options as a fraction of market capitalization is 10%, the stock will subsequently exhibit a negative abnormal return of between 3% and 5%. There is some evidence of market learning in that the abnormal returns tend to fall over time. We use a restricted sample of actual stock exercises and find that the reduced power of our trading rule does not reflect a reduced ability to predict stock option exercise. It also does not seem to reflect improved accounting disclosure since the portion of option costs recognized in diluted earnings per share appears to be priced by the market in all our sample years.

SSI for the Aged and the Problem of 'Take-Up'

The Supplemental Security Income (SSI) program provides an income and health care safety net for the elderly poor. The phenomenon of apparently eligible households that do not enroll in, or 'take up' SSI has been noted as a severe problem since the program's inception in 1974. This paper examines SSI eligibility, applications, and participation in the aged population from 1984 (the most recent year analyzed in the literature to date) through 1997. We are fortunate to have administrative data on SSI use that is linked to various panels of the SIPP. We use this information to estimate the SSI-aged application choice. The key findings from the earlier literature are sensitive with respect to exact sample specification, alternative approaches to imputing the expected SSI benefit, and more detailed information on application and receipt culled from administrative files. Our findings suggest that cash benefits may be less influential, and Medicaid access through SSI more influential, than previously estimated.

Creating a Supportive Culture for Online Teaching: A Case Study of a Faculty Learning Community

This case study describes the creation of a supportive culture for online teaching at a western university that was transitioning to a new learning management system. The case study highlighted the creation of a faculty learning community as one strategy to address the challenge of faculty working through a change process. The faculty learning community provided a space for the development of best practices in teaching, drawing from the pedagogical experiences of teachers from diverse disciplines. The learning community also provided a venue for expanding the technical knowledge level of faculty members with a range of comfort levels with varied technologies