Thermodynamics of the deposition of complex waxes and asphaltenes in crude oil

Peer reviewedPublisher PD

Public services: are composite measures a robust reflection of performance in the public sector?

A composite indicator is an aggregated index comprising individual performance indicators. Composite indicators integrate a large amount of information in a format that is easily understood and are therefore a valuable tool for conveying a summary assessment of performance in priority areas. This research investigates the degree to which composite measures are an appropriate metric for evaluating performance in the public sector. Do they reflect accurately the performance of organisations? To what degree are they influenced by the uncertainty surrounding underlying indicators on which they are based? Are they robust and stable over time? The construction of composite measures creates specific methodological challenges that make such questions especially pertinent. We address these through a series of quantitative analyses of panel data relating to healthcare (Star ratings of NHS acute Trusts) and local government (Comprehensive Performance Assessment (CPA) ratings of authorities) in England where composites have been widely used. The creation of a composite comprises a number of important steps, each of which requires careful judgement. These include the specification of the choice of indicators, the transformation of measured performance on individual indicators, the specification of a set of weights on individual indicators, and combining the indicators using aggregation methods or decision rules. We use Monte Carlo simulations to examine the robustness of performance judgements to these different technical choices. We show the extent to which composites provide stable performance rankings of organisations over time and assess whether variations are due to genuine performance improvement or merely the result of random statistical variation. The analysis suggests that the judgements that have to be made in the construction of the composite can have a significant impact on the resulting score. Technical and analytical issues in the design of composite indicators have important policy implications. We highlight the issues which need to be considered in the construction of robust composite indicators so that they can be designed in ways which will minimise the potential for producing misleading performance information which may fail to deliver the expected improvements or even induce unwanted side-effects.performance measurement, performance indicators, composite indicators

Exploring the impact of public services on quality of life indicators

The fundamental aim of public services is to improve the quality of life of citizens. The main objective of this study was to investigate the influence of public service organisations (PSOs) on aspects of quality of life (broadly measured) of citizens at a local level. We assembled a rich database using 20 of the 45 quality of life measures developed by the Audit Commission. Those we selected covered broad areas of quality of life such as safety, housing, health, education, and transport and were available at ‘small area’ level. We used a range of advanced statistical methods to analyse the relationships between PSOs and quality of life measures at different hierarchical levels. The techniques were selected to be robust when making comparisons between levels and when looking at associations between quality of life measures. Our descriptive analyses (bivariate correlations, factor analysis and ANOVA) suggested overall some significant correlations between some of the quality of life variables. The SUR model results also indicated that the quality of life indicators are correlated, and therefore that we should look at these measures in a joint modelling approach such as MVML, as envisaged in the study objectives.

The Effect of Budgets on Doctor Behaviour: Evidence From A Natural Experiment

In many health care systems primary care physicians act as 'gatekeepers' to secondary care. We investigates the impact of the UK fundholding scheme under which general practices could elect to hold a budget to meet the costs of elective surgery for their patients. We use a differences in differences methodology on a large four year panel of English general practices before and after the abolition of fundholding. Fundholding incentives reduced fundholder elective admission rates by 3.3% and accounted for 57% of the difference between fundholder and nonfundholder elective admissions, with 43% a selection effect due to unobservable differences in practice characteristics. Fundholding had no effect on emergency admissions.Budgets; Health care; Fundholding; Admission rates

The effects on waiting times of expanding provider choice:evidence from a policy experiment

Long waiting times for inpatient treatment in the UK National Health Service have long been a source of great popular and political concern, and therefore a target for policy initiatives. One such is the London Patient Choice Project, under which patients at risk of breaching inpatient waiting time targets were offered the choice of an alternative hospital with a guaranteed shorter wait. This paper uses a difference in difference econometric methodology to infer the impact of the choice project on ophthalmology waiting times. In line with our theoretical predictions, it finds that the project led to lower average waiting times in the London region and a convergence in waiting times amongst London hospitals.

Bifurcation in electrostatic resistive drift wave turbulence

The Hasegawa-Wakatani equations, coupling plasma density and electrostatic potential through an approximation to the physics of parallel electron motions, are a simple model that describes resistive drift wave turbulence. We present numerical analyses of bifurcation phenomena in the model that provide new insights into the interactions between turbulence and zonal flows in the tokamak plasma edge region. The simulation results show a regime where, after an initial transient, drift wave turbulence is suppressed through zonal flow generation. As a parameter controlling the strength of the turbulence is tuned, this zonal flow dominated state is rapidly destroyed and a turbulence-dominated state re-emerges. The transition is explained in terms of the Kelvin-Helmholtz stability of zonal flows. This is the first observation of an upshift of turbulence onset in the resistive drift wave system, which is analogous to the well-known Dimits shift in turbulence driven by ion temperature gradients.Comment: 21 pages, 11 figure

Using LiDAR to assess the effect of fire and floods on upland peat bogs, Waterfall Gully, Mount Lofty Ranges, South Australia

A flood exceeding the 100 year average recurrence interval in November 2005 led to the failure of an upland peat bog in Waterfall Gully. The area is prone to severe bushfire and flood events and the control dam at the base of First Falls was filled with sediment sourced from Wilson Bog. A resistant quartzite bar at Fourth Falls has formed a natural constriction point against which burnt logs and debris have collected following previous fire events forming a natural dam resulting in sediment/peat accumulation upstream. The failure of the bog was inevitable as the vegetative material in the log-jam progressively weakened and rotted. Intense flooding triggered the failure but it was augmented by the build up of a critical mass of sediment upstream of the restriction point. The downstream force of the flood waters and the weight of the saturated bog sediments was enough to overcome the basal frictional forces resulting in slumping and headward erosion. LiDAR data clearly shows an erosion channel scoured out by the flood. Approximately 5000 m3 of sediment (-10,100 tonnes) was washed downstream. LiDAR coupled with a tri-spectral scanner has the capacity to identify other upland peat bogs due to their high NDVI value and assess their stability on steep slopes or narrow valleys. Fire is another risk to the stability of these bogs as it has the potential to remove binding vegetation and expose unconsolidated sediments to erosion during subsequent rain events. Groundsurface and vegetation surface DEM\u27s generated from LiDAR combined with NDVI maps derived from a tri-spectral scanner provide an ideal tool to monitor and assess the risk of slumping in other upland peat bogs

The privilege of induction avoidance and calcineurin inhibitors withdrawal in 2 haplotype HLA matched white kidney transplantation

BACKGROUND: White recipients of 2-haplotype HLA-matched living kidney transplants are perceived to be of low immunologic risk. Little is known about the safety of induction avoidance and calcineurin inhibitor withdrawal in these patients. METHODS: We reviewed our experience at a single center and compared it to Organ Procurement and Transplantation Network (OPTN) registry data and only included 2-haplotype HLA-matched white living kidney transplants recipients between 2000 and 2013. RESULTS: There were 56 recipients in a single center (where no induction was given) and 2976 recipients in the OPTN. Among the OPTN recipients, 1285 received no induction, 903 basiliximab, 608 thymoglobulin, and 180 alemtuzumab. First-year acute rejection rates were similar after induction-free transplantation among the center and induced groups nationally. Compared with induction-free transplantation in the national data, there was no decrease in graft failure risk over 13 years with use of basiliximab (adjusted hazard ratio [aHR], 0.86; confidence interval [CI], 0.68-1.08), Thymoglobulin (aHR, 0.92; CI, 0.7-1.21) or alemtuzumab (aHR, 1.18; CI, 0.72-1.93). Among induction-free recipients at the center, calcineurin inhibitor withdrawal at 1 year (n = 27) did not significantly impact graft failure risk (HR,1.62; CI, 0.38-6.89). CONCLUSIONS: This study may serve as a foundation for further studies to provide personalized, tailored, immunosuppression for this very low-risk population of kidney transplant patients

Time is not enough : promoting strategic engagement with writing for publication

Research, scholarship and publication are central to the work of higher education. However, even academics with the necessary research and writing skills can struggle to publish as often as they would like. Research suggests that a writing retreat is one solution; there is a process going on there that addresses the problem, but how it does so has not been fully explained. We used a novel approach, containment theory, to explain why the functions of a structured retreat work. We argue that a retreat does more than simply provide time to write; it is a model for academics to meet the demands of research assessment. Finally, we conceptualise this as strategic engagement - a model for producing regular writing for publication while continuing to meet other professional demands