Lyapunov Stability Analysis for Invariant States of Quantum Systems

In this article, we propose a Lyapunov stability approach to analyze the convergence of the density operator of a quantum system. In contrast to many previously studied convergence analysis methods for invariant density operators which use weak convergence, in this article we analyze the convergence of density operators by considering the set of density operators as a subset of Banach space. We show that the set of invariant density operators is both closed and convex, which implies the impossibility of having multiple isolated invariant density operators. We then show how to analyze the stability of this set via a candidate Lyapunov operator.Comment: A version of this paper has been accepted at 56th IEEE Conference on Decision and Control 201

AE-C attitude determination and control prelaunch analysis and operations plan

A description of attitude control support being supplied by the Mission and Data Operations Directorate is presented. Included are descriptions of the computer programs being used to support the missions for attitude determination, prediction, and control. In addition, descriptions of the operating procedures which will be used to accomplish mission objectives are provided

Computer Assisted Instruction for Teaching Clinical Decision-Making

journal articleBiomedical Informatic

Why Public Goods Are a Pedagogical Bad

The concept of “public goods” is confusing because it confounds three analytically distinct concepts: excludability, rivalry, and public finance. Pure public goods are of limited relevance as an explanation of government spending. To make matters worse, the broader policy community uses the term in ways that invoke different means of both “public” and “good” than economists favour. For example, “global public goods” describe everything from the global environment, international financial stability and market efficiency, to health, knowledge, peace and security and humanitarian rights. In this essay, I argue for radically reducing the emphasis placed on public goods in the standard undergraduate public finance curriculum, and instead emphasizing the fundamental underlying issues of exclusion, rivalry, and public finance/provision. The ultimate aim of an undergraduate course in public expenditures should, I argue, be to explain government spending

The person, interactions and environment programme to improve care of people with dementia in hospital: a multisite study

Background: Improving care of people with dementia on acute hospital wards is a policy priority. Person-centred care is a marker of care quality; delivering such care is a goal for service improvement. Objectives: PIE (Person: Interaction; Environment) comprises an observation tool and systematic approach to implement and embed a person-centred approach in routine care for hospitalised patients with dementia. The study aims were to: evaluate PIE as a method to improve the care of older people with dementia on acute hospital wards; and develop insight into what person-centred care might look like in practice in this setting. Methods: We performed a longitudinal comparative case study design in ten purposively selected wards in five Trusts in three English regions; alongside an embedded process evaluation. Data was collected from multiple sources: staff, patients, relatives, organisational aggregate information and documents. Mixed methods were employed: ethnographic observation; interviews and questionnaires; patient case studies (patient observation and conversations ‘in the moment’, interviews with relatives and case records), patient and ward aggregate data. Data was synthesised to create individual case studies of PIE implementation and outcomes in context of ward structure, organisation, patient profile and process of care delivery. Cross case comparison facilitated a descriptive and explanatory account of PIE implementation in context, the pattern of variation, what shaped it and the consequences flowing from it. Quantitative data was analysed using simple descriptive statistics. Qualitative data analysis employed grounded theory methods. Results: The study furthered understanding of dimensions of care quality for older people with dementia on acute hospital wards and the environmental, organisational and cultural factors that shaped delivery. Only two wards fully implemented PIE, sustaining and embedding change over 18 months. The remaining wards either did not install PIE (‘non-implementers’); or were ‘partial implementers’. The interaction between micro-level contextual factors (aspects of leadership (drivers, facilitators, team, networks), fit with strategic initiatives and salience with valued goals) and miso and macro level organisational factors, were the main barriers to PIE adoption. Where implemented, evidence suggests that the programme directly affected improvement in ward practice with positive impact on the experience of patients and caregivers, although the heterogeneity of need and severity of impairment meant that some of the more visible changes did not affect everyone equally. Limitations: Although PIE has potential to improve the care of people with dementia when implemented, findings are indicative only: data on clinical outcomes was not systematically collected; and PIE was not adopted on most study wards. Research implications: Further research is required to identify more precisely the skill-mix and resources necessary to provide person-focused care to hospitalised people with dementia, across the spectrum of need, including those with moderate and severe impairment. Implementing innovations to change practices in complex organisations requires more in-depth understanding of contextual factors that impact the capacity of organisations to absorb and embed new practices

A near-infrared spectroscopic screening of the red giant populations in omega Centauri

Near-infrared spectra of 21 giants in omega Centauri, spanning the whole range of metallicities observed in this cluster, are presented. This work is part of a coordinated photometric and spectroscopic campaign in the optical and in the infrared, aimed at studying the complex stellar population of omega Centauri and understanding its formation and chemical evolution. By analyzing the several CO and OH molecular bands and atomic lines in the spectra of the selected giants, metal abundances and abundance ratios have been obtained. The existence of three major metallicity regimes at [Fe/H]=-1.6, -1.2 and [Fe/H]<-0.5 has been confirmed. The most metal-rich stars in our sample show a lower (if any) alpha-enhancement when compared to the more metal-poor components, suggesting that they should have formed in a medium significantly polluted by type Ia supernova ejecta. Isotopic carbon abundances have been also inferred, providing an average 13C/12C=4, which clearly indicates that extra-mixing processes occurred in the stellar interiors during the ascent on the Red Giant Branch.Comment: 22 pages, 7 .ps figures. aastex. Accepted for pubilcation in the Astrophysical Journa

Coding accuracy for Parkinson's disease hospital admissions:implications for healthcare planning in the UK

ObjectivesHospital Episode Statistics data are used for healthcare planning and hospital reimbursements. Reliability of these data is dependent on the accuracy of individual hospitals reporting Secondary Uses Service (SUS) which includes hospitalisation. The number and coding accuracy for Parkinson's disease hospital admissions at a tertiary centre in Birmingham was assessed.Study designRetrospective, routine-data–based study.MethodsA retrospective electronic database search for all Parkinson's disease patients admitted to the tertiary hospital over a 4-year period (2009–2013) was performed on the SUS database using International Classification of Disease codes, and on the local inpatient electronic prescription database, Prescription and Information Communications System, using medication prescriptions. Capture-recapture methods were used to estimate the number of patients and admissions missed by both databases.ResultsFrom the two databases, between July 2009 and June 2013, 1068 patients with Parkinson's disease accounted for 1999 admissions. During these admissions, the Parkinson's disease was coded as a primary or secondary diagnosis. Ninety-one percent of these admissions were recorded on the SUS database. Capture-recapture methods estimated that the number of Parkinson's disease patients admitted during this period was 1127 patients (95% confidence interval: 1107–1146). A supplementary search of both SUS and Prescription and Information Communications System was undertaken using the hospital numbers of these 1068 patients. This identified another 479 admissions. SUS database under-estimated Parkinson's disease admissions by 27% during the study period.ConclusionThe accuracy of disease coding is critical for healthcare policy planning and must be improved. If the under-reporting of Parkinson's disease admissions on the SUS database is repeated nationally, expenditure on Parkinson's disease admissions in England is under-estimated by approximately £61 million per year