ULTRACAM photometry of the eclipsing cataclysmic variable OU Vir

We present high-speed, three-colour photometry of the faint eclipsing cataclysmic variable OU Vir. For the first time in OU Vir, separate eclipses of the white dwarf and the bright spot have been observed. We use timings of these eclipses to derive a purely photometric model of the system, obtaining a mass ratio of q=0.175+/-0.025, an inclination of i=79.degrees2+/-0.degrees7 and a disc radius of R-d/a=0.2315+/-0.0150. We separate the white dwarf eclipse from the light curve and, by fitting a blackbody spectrum to its flux in each passband, obtain a white dwarf temperature of T=13900+/-600 K and a distance of D=51+/-17 pc. Assuming that the primary obeys the Nauenberg mass-radius relation for white dwarfs and allowing for temperature effects, we also find a primary mass M-w/M-circle dot=0.89+/-0.20, a primary radius R-w/R-circle dot=0.0097+/-0.0031 and an orbital separation a/R-circle dot=0.74+/-0.05.

Secondary prevention of cardiovascular disease in different primary healthcare systems with and without pay-for-performance

Objective: To compare baseline cardiovascular risk management between people recruited from two different healthcare systems, to a research trial of an intervention to optimize secondary prevention. Design: Cross-sectional study. Setting: General practices, randomly selected: 16 in Northern Ireland (NI) (UK NHS, ‘strong’ infrastructure); 32 in Republic of Ireland (RoI) (mixed healthcare economy, less infrastructure). Patients: 903 (mean age 67.5 years; 69.9% male); randomly selected, known coronary heart disease. Main outcome measures: Blood pressure, cholesterol, medications; validated questionnaires for diet (DINE), exercise (Godin), quality of life (SF12); healthcare usage. Results: More RoI than NI participants had systolic BP>140 mmHg (37% v 28%, p=0.01) and cholesterol >5mmol/l (24% v 17%, p=0.02): RoI mean systolic BP was higher (139 v 132 mm Hg). More RoI participants reported a high fibre intake (35% v 23%), higher levels of physical activity (62% v 44%), and better physical and mental health (SF12); they had more GP (5.6 v 4.4) and fewer nurse visits (1.6 v 2.1) in the previous year. Fewer in RoI (55% v 70%) were prescribed B blockers. Both groups’ ACE inhibitor (41%; 48%) prescribing was similar; high proportions were prescribed statins (84%; 85%) and aspirin (83%; 77%). Conclusions Blood pressure and cholesterol are better controlled among patients in a primary healthcare system with a ‘strong’ infrastructure supporting computerization and rewarding measured performance but this is not associated with healthier lifestyle or better quality of life. Further exploration of differences in professionals’ and patients’ engagement in secondary prevention in different healthcare systems is needed.

National and Provincial Influences on Public Sector Pay: Northern Ireland after 1945

This article examines the national and regional pressures in Northern Ireland in the post-war period for parity in public sector pay with the rest of the UK. Northern Ireland had a devolved legislature and government within the UK from 192 1 and was constitutionality in all essentially federal relationship with the rest of the UK. However, the Stormont Government chose to use legislative devolution to minimize policy differences with the rest of the UK. The article highlights the national industrial relations environment as the backdrop for provincial developments in pay setting. It establishes the important role Played by the Social Services Agreement negotiated with the Labour Government at Westminster in triggering the principle of parity in public sector pay in the early post-war years. The principle of pay parity subsequently became a benchmark for regional trade union coercive comparisons in collective bargaining across the devolved public sector. The article highlights the Policy relevance of these developments both to the UK Treasury and to devolved Governments in the UK, as they address the issue of regional public sector pay.

The convex variable step-size (CVSS) algorithm

This letter introduces the convex variable step-size (CVSS) algorithm. The convexity of the resulting cost function is guaranteed. Simulations presented show that with the proposed algorithm, we obtain similar results, as with the VSS algorithm in initial convergence, while there are potential performance gains when abrupt changes occur.

Convergence and tracking analysis of a variable normalised LMF (XE-NLMF) algorithm

The least-mean-fourth (LMF) algorithm is known for its fast convergence and lower steady state error, especially in sub-Gaussian noise environments. Recent work on normalised versions of the LMF algorithm has further enhanced its stability and performance in both Gaussian and sub-Gaussian noise environments. For example, the recently developed normalised LMF (XE-NLMF) algorithm is normalised by the mixed signal and error powers, and weighted by a fixed mixed-power parameter. Unfortunately, this algorithm depends on the selection of this mixing parameter. In this work, a time-varying mixed-power parameter technique is introduced to overcome this dependency. A convergence analysis, transient analysis, and steady-state behaviour of the proposed algorithm are derived and verified through simulations. An enhancement in performance is obtained through the use of this technique in two different scenarios. Moreover, the tracking analysis of the proposed algorithm is carried out in the presence of two sources of nonstationarities: (1) carrier frequency offset between transmitter and receiver and (2) random variations in the environment. Close agreement between analysis and simulation results is obtained. The results show that, unlike in the stationary case, the steady-state excess mean-square error is not a monotonically increasing function of the step size. (c) 2007 Elsevier B.V. All rights reserved.

Towards variance-matrix characterization of complementarity relations in a continuous variable system

We discuss complementarity relations in a bipartite continuous variable system. Building up from the work done on discrete d-dimensional systems, we prove that for symmetric two-mode states, quantum complementarity relations can be put in a simple relation with the elements of the variance matrix. When this condition is not satisfied, such a connection becomes non-trivial. Our investigation is the first step towards an operative characterization of the complementarity in a scenario that has not been investigated so far.