Phase II control charts for autocorrelated processes

A large amount of SPC procedures are based on the assumption that the process subject to monitoring consists of independent observations. Chemical processes as well as many non-industrial processes exhibit autocorrelation, for which the above-mentioned control procedures are not suitable. This paper proposes a Phase II control procedure for autocorrelated and possibly locally stationary processes. A time-varying autoregressive (AR) model is proposed, which is capable of dealing with the autocorrelation as well as with local non-stationarities of the temporal process. Such non-stationarities are induced by the time-varying nature of the AR coefficients. The model is optimized during Phase I when it is assured that the process is in control and as a result the model describes accurately the process. The Phase II proposed control procedure is based on a comparison of the current time series model with an alternative model, measuring deviations from it. This comparison is carried out using Bayes factors, which help to establish the in-control or out-of-control state of the process in Phase II. Using the threshold rules of the Bayes factors, we propose a binomial-type control procedure for the monitoring of the process. The methodology of this paper is illustrated using two data sets consisting of temperature measurements at two different stages in the manufacturing of a plastic mould

Low-Energy Brane-World Effective Actions and Partial Supersymmetry Breaking

As part of a programme for the general study of the low-energy implications of supersymmetry breaking in brane-world scenarios, we study the nonlinear realization of supersymmetry which occurs when breaking N=2 to N=1 supergravity. We consider three explicit realizations of this supersymmetry breaking pattern, which correspond to breaking by one brane, by one antibrane or by two (or more) parallel branes. We derive the minimal field content, the effective action and supersymmetry transformation rules for the resulting N=1 theory perturbatively in powers of kappa = 1/M_{Planck}. We show that the way the massive gravitino and spin-1 fields assemble into N=1 multiplets implies the existence of direct brane-brane contact interactions at order O(kappa). This result is contrary to the O(kappa^2) predicted by the sequestering scenario but in agreement with recent work of Anisimov et al. Our low-energy approach is model independent and is a first step towards determining the low-energy implications of more realistic brane models which completely break all supersymmetries.Comment: Latex, 29 Page

Intersection rules, dynamics and symmetries

We consider theories containing gravity, at most one dilaton and form field strengths. We show that the existence of particular BPS solutions of intersecting extremal closed branes select the theories, which upon dimensional reduction to three dimensions possess a simple simply laced Lie group symmetry G. Furthermore these theories can be fully reconstructed from the dynamics of such branes and of their openings. Amongst such theories are the effective actions of the bosonic sector of M-theory and of the bosonic string. The BPS intersecting brane solutions form representations of a subgroup of the group of Weyl reflections and outer automorphisms of the triple Kac-Moody extension G+++ of the G algebra, which cannot be embedded in the overextended Kac-Moody subalgebra G++ characterising the cosmological Kasner solutions.Comment: Latex 30 pages, 3 figure

Nonlinear Realization of N=2 Superconformal Symmetry and Brane Effective Actions

Due to the incompatibility of the nonlinear realization of superconformal symmetry and dilatation symmetry with the dilaton as the compensator field, in the present paper it shows an alternative mechanism of spontaneous breaking the N=2 superconformal symmetry to the N=0 case. By using the approach of nonlinear transformations it is found that it leads to a space-filling brane theory with Weyl scale W(1,3) symmetry. The dynamics of the resulting Weyl scale invariant brane, along with that of other Nambu-Goldstone fields, is derived in terms of the building blocks of the vierbein and the covariant derivative from the Maurer-Cartan oneforms. A general coupling of the matter fields localized on the brane world volume to these NG fields is also constructed.Comment: 22 pages, more references and comments are adde

Blood pressure, lipids, and obesity are associated with reteinopathy - The Hoorn study

OBJECTIVE - To study potential risk factors for retinopathy in diabetic and nondiabetic individuals. RESEARCH DESIGN AND METHODS - The Hoorn Study is a population-based study including 2,484 50- to 74-year-old Caucasians. A subsample of 626 individuals stratified by age, sex, and glucose tolerance underwent extensive measurements during 1989-1992, including ophthalmologic examination and two-field 45-degree fundus photography. The prevalence of (diabetic) retinopathy was assessed among individuals with normal glucose metabolism (NGM) and impaired glucose metabolism (IGM) and individuals with newly diagnosed diabetes mellitus (NDM) and known diabetes mellitus (KDM) (new World Health Organization 1999 criteria). RESULTS - The prevalence of retinopathy was 9% in NGM, 11% in IGM, 13% in NDM, and 34% in KDM. Retinopathy worse than minimal nonproliferative diabetic retinopathy was present in 8% in KDM and 0-2% in other glucose categories. The prevalence of retinopathy was positively associated with elevated blood pressure, BMI, cholesterol, and triglyceride serum levels in all glucose categories. The age-, sex-, and glucose metabolism category-adjusted odds ratios were 1.5 (95% CI 1.2-1.9), 1.3 (1.0-1.7), and 1.3 (1.0-1.6) per SD increase of systolic blood pressure, BMI, and total cholesterol concentration, respectively, and 1.2 (1.0-1.5) per 50% increase of triglyceride level. Elevated blood pressure and plasma total and LDL cholesterol levels showed associations with retinal hard exudates. CONCLUSIONS - Retinopathy is a multifactorial microvascular complication, which, apart from hyperglycemia, is associated with blood pressure, lipid concentrations, and BMI

Analysis of a Web-Based Dashboard to Support the Use of National Audit Data in Quality Improvement: Realist Evaluation

YesDashboards can support data-driven quality improvements in health care. They visualize data in ways intended to ease cognitive load and support data comprehension, but how they are best integrated into working practices needs further investigation. This paper reports the findings of a realist evaluation of a web-based quality dashboard (QualDash) developed to support the use of national audit data in quality improvement. QualDash was co-designed with data users and installed in 8 clinical services (3 pediatric intensive care units and 5 cardiology services) across 5 health care organizations (sites A-E) in England between July and December 2019. Champions were identified to support adoption. Data to evaluate QualDash were collected between July 2019 and August 2021 and consisted of 148.5 hours of observations including hospital wards and clinical governance meetings, log files that captured the extent of use of QualDash over 12 months, and a questionnaire designed to assess the dashboard's perceived usefulness and ease of use. Guided by the principles of realist evaluation, data were analyzed to understand how, why, and in what circumstances QualDash supported the use of national audit data in quality improvement. The observations revealed that variation across sites in the amount and type of resources available to support data use, alongside staff interactions with QualDash, shaped its use and impact. Sites resourced with skilled audit support staff and established reporting systems (sites A and C) continued to use existing processes to report data. A number of constraints influenced use of QualDash in these sites including that some dashboard metrics were not configured in line with user expectations and staff were not fully aware how QualDash could be used to facilitate their work. In less well-resourced services, QualDash automated parts of their reporting process, streamlining the work of audit support staff (site B), and, in some cases, highlighted issues with data completeness that the service worked to address (site E). Questionnaire responses received from 23 participants indicated that QualDash was perceived as useful and easy to use despite its variable use in practice. Web-based dashboards have the potential to support data-driven improvement, providing access to visualizations that can help users address key questions about care quality. Findings from this study point to ways in which dashboard design might be improved to optimize use and impact in different contexts; this includes using data meaningful to stakeholders in the co-design process and actively engaging staff knowledgeable about current data use and routines in the scrutiny of the dashboard metrics and functions. In addition, consideration should be given to the processes of data collection and upload that underpin the quality of the data visualized and consequently its potential to stimulate quality improvement.This research was funded by the National Institute for Health Research Health Services and Delivery Research Program (project #16/04/06)

Design and evaluation of an interactive quality dashboard for national clinical audit data: a realist evaluation

YesBackground: National audits aim to reduce variations in quality by stimulating quality improvement. However, varying provider engagement with audit data means that this is not being realised. Aim: The aim of the study was to develop and evaluate a quality dashboard (i.e. QualDash) to support clinical teams’ and managers’ use of national audit data. Design: The study was a realist evaluation and biography of artefacts study. Setting: The study involved five NHS acute trusts. Methods and results: In phase 1, we developed a theory of national audits through interviews. Data use was supported by data access, audit staff skilled to produce data visualisations, data timeliness and quality, and the importance of perceived metrics. Data were mainly used by clinical teams. Organisational-level staff questioned the legitimacy of national audits. In phase 2, QualDash was co-designed and the QualDash theory was developed. QualDash provides interactive customisable visualisations to enable the exploration of relationships between variables. Locating QualDash on site servers gave users control of data upload frequency. In phase 3, we developed an adoption strategy through focus groups. ‘Champions’, awareness-raising through e-bulletins and demonstrations, and quick reference tools were agreed. In phase 4, we tested the QualDash theory using a mixed-methods evaluation. Constraints on use were metric configurations that did not match users’ expectations, affecting champions’ willingness to promote QualDash, and limited computing resources. Easy customisability supported use. The greatest use was where data use was previously constrained. In these contexts, report preparation time was reduced and efforts to improve data quality were supported, although the interrupted time series analysis did not show improved data quality. Twenty-three questionnaires were returned, revealing positive perceptions of ease of use and usefulness. In phase 5, the feasibility of conducting a cluster randomised controlled trial of QualDash was assessed. Interviews were undertaken to understand how QualDash could be revised to support a region-wide Gold Command. Requirements included multiple real-time data sources and functionality to help to identify priorities. Conclusions: Audits seeking to widen engagement may find the following strategies beneficial: involving a range of professional groups in choosing metrics; real-time reporting; presenting ‘headline’ metrics important to organisational-level staff; using routinely collected clinical data to populate data fields; and dashboards that help staff to explore and report audit data. Those designing dashboards may find it beneficial to include the following: ‘at a glance’ visualisation of key metrics; visualisations configured in line with existing visualisations that teams use, with clear labelling; functionality that supports the creation of reports and presentations; the ability to explore relationships between variables and drill down to look at subgroups; and low requirements for computing resources. Organisations introducing a dashboard may find the following strategies beneficial: clinical champion to promote use; testing with real data by audit staff; establishing routines for integrating use into work practices; involving audit staff in adoption activities; and allowing customisation. Limitations: The COVID-19 pandemic stopped phase 4 data collection, limiting our ability to further test and refine the QualDash theory. Questionnaire results should be treated with caution because of the small, possibly biased, sample. Control sites for the interrupted time series analysis were not possible because of research and development delays. One intervention site did not submit data. Limited uptake meant that assessing the impact on more measures was not appropriate. Future work: The extent to which national audit dashboards are used and the strategies national audits use to encourage uptake, a realist review of the impact of dashboards, and rigorous evaluations of the impact of dashboards and the effectiveness of adoption strategies should be explored. Study registration: This study is registered as ISRCTN18289782.This project was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme and will be published in full in Health and Social Care Delivery Research; Vol. 10, No. 12. See the NIHR Journals Library website for further project information