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

Participation in Higher Education: A Random Parameter Logit Approach with Policy Simulations

In this paper we present a theoretical model of higher education participation. We assume that young people that complete upper secondary education are faced with three choices, go to higher education, not go to higher education or go to higher education and work part time. Utilizing the Living in Ireland survey data 1994-2001 we model this choice in an Irish context by variation in costs (direct and indirect), the estimated lifecycle returns and household credit constraints. Using a random parameters logit choice model we find that simulated lifecycle earnings positively impact the educational/labour choices of young individuals in Ireland. This positive relationship is also found to be true for a choice-specific household income variable constructed in the paper. From the random parameters logit estimations we also find that preferences for choices with higher simulated lifecycle earnings and household income vary across individuals. We conduct policy simulations from our estimations and found that increasing student financial aid levels by 10% combined with a slight widening of the income limits for these aids can lead to significant movement away from the decision to not enter higher education.higher education participation, random parameters logit model, lifecycle simulated earnings, higher education policy

Utilising Microsimulation to Estimate New Marginal Returns to Education: Ireland 1987-2005

In this paper we utilise microsimulation techniques in the form of an income generation model and a tax/benefit model to estimate both the fiscal and net private return to education at a marginal level. This is carried out empirically using Irish data across the period 1987-2005 and is the first study to utilise these techniques in such a manner. The results indicate that a more generous tax/benefit system, combined with a greater state burden of the cost of education over this period may have helped increase the individual’s return to education, while reducing the state return from investing in education. The methodology employed allows us to specifically analyse the impact of various components of the tax/benefit system upon these returns across time and show the role of income tax changes upon the return to education for the individual and the state.returns to education, microsimulation, income generation model

Do private equity buyouts represent value for target shareholders? Premiums in the boom of the early 2000s

This study compares the takeover premiums for 55 private equity buyouts with 59 takeovers involving a public acquirer, from the US takeover market between 2004 and 2007. This investigation takes place amidst accusations of anti-competitive behavior against some of the most active private equity groups in the US. While controlling for several other factors that might affect the takeover premium, we find weak evidence that bid premiums are significantly lower for target firms undergoing a private equity takeover than those subject to takeovers by public companies. We also demonstrate that abnormal returns earned by targets around takeover announcements can be a biased and misleading proxy for takeover premium.

The Life-cycle Impact of Alternative Higher Education Finance Systems in Ireland

With increasing numbers of young people participating in higher education in Ireland and a heavy reliance of higher education institutions on State funding, the introduction of an alternative finance system for Ireland has been muted over the past number of years. However, no study has been conducted to gauge the potential impact of such measures. In this paper we utilise a dynamic microsimulation model developed for Ireland to simulate the impact of both an income contingent loan system (ICL) and a graduate tax system from a fiscal and redistributional viewpoint and to analyse the repayment length under the former system. Our results suggest that an ICL system could be more equitable, while the graduate tax system could be a better alternative from a fiscal viewpoint. The results also illustrate the importance of the interest rate attached to any future student loan system within Ireland from a fiscal viewpoint

The Determinants of Higher Education Participation in Ireland: A Micro Analysis

In this paper we present a theoretical model of higher education participation in Ireland. Utilising the Living in Ireland Survey data we model the impact of costs (direct and indirect), the estimated life cycle returns, environmental and parental influences and also household credit constraints on the higher education participation decision. We find that foregone earnings and youth employment rates have a negative impact on this decision; this suggests weaker labour markets for young people may have a positive impact on higher education participation. The insignificance of credit constraints in the shape of household income and maintenance grant eligibility from our estimations can also help draw some tentative policy conclusions. Our results also show that life cycle returns and parental educational level may influence participation in higher education in Ireland.

Investigating the suitability of high content image analysis as a tool to assess the reversibility of foamy alveolar macrophage phenotypes in vitro.

Many potential inhaled medicines fail during development due to the induction of a highly vacuolated or “foamy” alveolar macrophage phenotype response in pre-clinical studies. There is limited understanding if this response to an inhaled stimulus is adverse or adaptive, and additionally if it is a transient or irreversible process. The aim of this study was to evaluate whether high content image analysis could distinguish between different drug-induced foamy macrophage phenotypes and to determine the extent of the reversibility of the foamy phenotypes by assessing morphological changes over time. Alveolar-like macrophages derived from the human monocyte cell line U937 were exposed for 24 h to compounds known to induce a foamy macrophage phenotype (amiodarone, staurosporine) and control compounds that are not known to cause a foamy macrophage phenotype in vitro (fluticasone and salbutamol). Following drug stimulation, the cells were rested in drug-free media for the subsequent 24 or 48 h. Cell morphometric parameters (cellular and nuclear area, vacuoles numbers and size) and phospholipid content were determined using high content image analysis. The foamy macrophage recovery was dependent on the mechanism of action of the inducer compound. Amiodarone toxicity was associated with phospholipid accumulation and morphometric changes were reversed when the stimulus was removed from culture environment. Conversely cells were unable to recover from exposure to staurosporine which initiates the apoptosis pathway. This study shows that high content analysis can discriminate between different phenotypes of foamy macrophages and may contribute to better decision making in the process of new drug development.Peer reviewedFinal Published versio

Lifecycle Impact of Alternative Higher Education Finance Systems in Ireland

With increasing numbers of young people participating in higher education in Ireland and a heavy reliance of higher education institutions on state funding, the introduction of an alternative finance system for Ireland has been muted over the past number of years. However, no study has been conducted to gauge the potential impact of such measures. In this chapter we utilize a dynamic microsimulation model developed for Ireland to simulate the impact of both an income contingent loan system (ICL) and a graduate tax system from a fiscal and redistributional viewpoint and to analyze the repayment length under the former system. Our results suggest that an ICL system would is more equitable, while the graduate tax system would be a better alternative from a fiscal viewpoint. The results also illustrate the important of the interest rate attached to any future student loan system within Ireland from a fiscal viewpoint.graduate tax, income contingent loan, dynamic microsimulation, higher education financing

Physicochemical characterisation of inhalation grade lactose after the removal of intrinsic fines

Lactose is a common excipient in Dry Powder Inhaler (DPI) formulations, used as a carrier for the micronized drug particles. The presence of intrinsic lactose fines in the formulation influences its performance and their role and interactions between the lactose carrier and the micronized drug is still not fully understood. As a first step towards this investigation, “clean” lactose, with removed fines, was produced via wet decantation. Ethanol and isopropyl alcohol have been used in wet decantation, successfully removing lactose fines from the surface of the coarse particles. Differential Scanning Calorimetry (DSC) was employed to show that the powders maintained their crystalline character. Scanning Electron Microscopy (SEM) showed tomahawk-shaped particles in all the powders and some surface alteration occurring after decantation. An airflow titration method using laser diffraction (LDA) allowed the estimation of the removal of fines as well as the particle size distributions, while the non-polar and the polar components of the surface energy of the powders were calculated via Inverse Gas Chromatography-Surface Energy Analysis (iGC-SEA). As both solvents successfully removed fines, we propose the addition of isopropyl alcohol in the list of organic solvents suitable for this purpose.Peer reviewe