On the stability of solutions of the Lichnerowicz-York equation

We study the stability of solution branches for the Lichnerowicz-York equation at moment of time symmetry with constant unscaled energy density. We prove that the weak-field lower branch of solutions is stable whilst the upper branch of strong-field solutions is unstable. The existence of unstable solutions is interesting since a theorem by Sattinger proves that the sub-super solution monotone iteration method only gives stable solutions.Comment: To appear in Classical and Quantum Gravit

Gaming in the Irish Single Electricity Market and Potential Effects on Wholesale Prices. ESRI WP488. August 2014

The Irish Single Electricity Market is establishing how to comply with the European Union Target Model. One option is to move away from the regulated environment used in the current design and allow generating firms to bid freely in the market. This study shows that in 2011, allowing firms to freely compete in quantities (Cournot) would have increased prices by 52%, using Irish-specific estimates for the price elasticity of demand. When redesigning the market, regulators should consider how best to control market power

Perceptual impairment in face identification with poor sleep

Previous studies have shown impaired memory for faces following restricted sleep. However, it is not known whether lack of sleep impairs performance on face identification tasks that do not rely on recognition memory, despite these tasks being more prevalent in security and forensic professions—for example, in photo-ID checks at national borders. Here we tested whether poor sleep affects accuracy on a standard test of face-matching ability that does not place demands on memory: the Glasgow Face-Matching Task (GFMT). In Experiment 1, participants who reported sleep disturbance consistent with insomnia disorder show impaired accuracy on the GFMT when compared with participants reporting normal sleep behaviour. In Experiment 2, we then used a sleep diary method to compare GFMT accuracy in a control group to participants reporting poor sleep on three consecutive nights—and again found lower accuracy scores in the short sleep group. In both experiments, reduced face-matching accuracy in those with poorer sleep was not associated with lower confidence in their decisions, carrying implications for occupational settings where identification errors made with high confidence can have serious outcomes. These results suggest that sleep-related impairments in face memory reflect difficulties in perceptual encoding of identity, and point towards metacognitive impairment in face matching following poor sleep

Should Coal Replace Coal? Options for the Irish Electricity Market. ESRI WP428. March 2012

The Moneypoint coal plant is nearing the end of its useful life and will need to be replaced. For Moneypoint’s replacement, we consider different types of baseload technologies: coal plants with and without carbon capture, combined-cycle gas plants and a nuclear plant. This paper compares how the different types of plant are likely to affect the net costs of the Single Electricity Market under a number of fossil fuel and carbon price scenarios and highlights issues that might be of interest to final consumers and policy makers, namely effects on short-run prices, emissions and energy security

Distance Effects, Social Class and the Decision to Participate in Higher Education in Ireland. ESRI WP444. December 2012

While a number of international studies have attempted to assess the influence of geographic accessibility on the decision to participate in higher education, this issue has not been addressed in detail in an Irish context. The aim of this paper is to fill this gap and to present a higher education choice model that estimates the impact of travel distance on the decision of school leavers to proceed to higher education in Ireland, while also controlling for a range of individual level characteristics and school related variables. To do so we use data from the 2007 wave of the School Leavers’ Survey. We find that, on average, travel distance is not an important factor in the higher education participation decision, when factors such as student ability are accounted for. However, further analysis shows that travel distance has a significantly negative impact on participation for those from lower social classes and that this impact grows stronger as distance increases. We also find that the distance effects are most pronounced for lower ability students from these social backgrounds. This has important implications for higher education policy in Ireland, especially in relation to equity of access and the design of the maintenance grant system

Irish and British historical electricity prices and implications for the future. ESRI WP452. April 2013

This paper compares retail and wholesale electricity prices in SEM, the market of the island of Ireland, and BETTA in Great Britain. Wholesale costs are much lower in BETTA. We show that this is mostly because the wholesale price in BETTA is set too low to cover generation costs, although it is compensated by large retail margins. The substantial need for new investment in generation in Great Britain suggests that returns to generators will have to increase. Developing a market mechanism to compensate generators fairly while simultaneously reducing retail revenue will help in achieving this goal

Strategic bidding, wind ownership and regulation in a decentralised electricity market

Market power often emerges in wholesale electricity markets. Regulators use several strategies to limit market power: adopting bidding rules, compulsory forward markets and enhancing demand response. We study the case of the Irish Single Electricity Market (SEM), where the market will eliminate strict bidding rules to comply with the European Target Electricity Model. Using the PLEXOS unit-commitment model, we simulate the price that emerges in Cournot competition and find that it is more than 60% higher than in perfect competition. We then study how much the price varies with three measures that influence market power. Limiting thermal generators’ ownership of wind generation does not affect prices. Forcing the largest firm to sell some of its output forward decreases prices, but keeps them well above competitive levels. The most effective measure is an increase in price elasticity of demand, although existing evidence shows that it is hard to achieve. We conclude that regulatory oversight of bids will have to continue, although the Target Model will be associated with limited transparency, creating further challenges