Concepts for design of an energy management system incorporating dispersed storage and generation

New forms of generation based on renewable resources must be managed as part of existing power systems in order to be utilized with maximum effectiveness. Many of these generators are by their very nature dispersed or small, so that they will be connected to the distribution part of the power system. This situation poses new questions of control and protection, and the intermittent nature of some of the energy sources poses problems of scheduling and dispatch. Under the assumption that the general objectives of energy management will remain unchanged, the impact of dispersed storage and generation on some of the specific functions of power system control and its hardware are discussed

The secretion of von Willebrand factor from endothelial cells; an increasingly complicated story.

von Willebrand factor (VWF) plays key roles in both primary and secondary hemostasis by capturing platelets and chaperoning clotting factor VIII, respectively. It is stored within the Weibel-Palade bodies (WPBs) of endothelial cells as a highly prothrombotic protein, and its release is thus necessarily under tight control. Regulating the secretion of VWF involves multiple layers of cellular machinery that act together at different stages, leading to the exocytic fusion of WPBs with the plasma membrane and the consequent release of VWF. This review aims to provide a snapshot of the current understanding of those components, in particular the members of the Rab family, acting in the increasingly complex story of VWF secretion

Randomized, double-blind comparison of patient-controlled epidural infusion vs nurse-administered epidural infusion for postoperative analgesia in patients undergoing colonic resection

Background. There is little published evidence of the analgesic efficacy of patient-controlled epidural analgesia (PCEA) for postoperative pain relief. The aim of this study was to compare the analgesic efficacy of epidural infusion of bupivacaine 0.125% and fentanyl 4 μg ml-1 administered by either PCEA with a background infusion or nurse-administered continuous epidural infusion (CEI) after major intra-abdominal surgery. Methods. In a double-blind, randomized clinical trial, 205 adult patients undergoing colonic resection by laparotomy received either PCEA or CEI. Pain scores were recorded via a fourpoint verbal rating scale at 1, 2, 3, 4, 8, 12, 24, 48, and 72 h after surgery. The administration of epidural top-ups and systemic analgesia over the same period was also recorded, and patient satisfaction questionnaires completed. Results. The median area under the curve of pain against time was significantly lower in the PCEA group (2 vs 24, P<0.001) as were median summary pain scores on movement (0.67 vs 1.33, P<0.001). Significantly fewer patients in the PCEA group received one or more epidural top-ups (13 vs 36%, P=0.0002) or any systemic analgesics (41 vs 63%, P=0.0021). Patients in the PCEA group were significantly more likely to be very satisfied than in the CEI group (76 vs 43%, P<0.0001). Conclusions. PCEA provides greater analgesic efficacy than CEI for postoperative analgesia after major intra-abdominal surgery, and a decreased requirement for physician or nurse intervention

High Performing Hospital Enterprise Architecture: Insights from a Multi-method Exploratory Case

The US healthcare system is a critical infrastructure grappling with as much as 16% of the GDP in its expenditures and unsatisfactory outcomes, and undergoing considerable public scrutiny. High ranking officials have both singled out the US healthcare system as the most expensive and among the least effective in the developed world. Hospitals hoping to find “The Toyota Way” so as to rid themselves of waste through lean and six sigma improvement initiatives, have mostly focused in applying tools at a process level, rather than adopting an enterprise perspective and understanding the full breadth of their socio-technical complexity. This paper adopts a systems thinking approach in describing a leading Boston hospital’s enterprise architecture through a multi-method exploratory case. The initial exploratory question proposed by hospital senior leadership was “How to speed patient flow in the Emergency Department?”, however as results became available, the scope was expanded to include the whole hospital enterprise. Both qualitative and quantitative data evidence were collected through a variety of methods, namely observation, archival records, documentation, and interviews. Analysis includes techniques consistent with the grounded theory approach, as well as more traditional quantitative data analysis. Hospital enterprise performance is hypothesized to be related to hospital enterprise architecture, and an alternative hospital enterprise architecture is proposed as well as future work

Magnetization reversal times in the 2D Ising model

We present a theoretical framework which is generally applicable to the study of time scales of activated processes in systems with Brownian type dynamics. This framework is applied to a prototype system: magnetization reversal times in the 2D Ising model. Direct simulation results for the magnetization reversal times, spanning more than five orders of magnitude, are compared with theoretical predictions; the two agree in most cases within 20%.Comment: 9 pages, 8 figure

Validation of a fornix depth measurer: a putative tool for the assessment of progressive cicatrising conjunctivitis

Background/aims Documentation of conjunctival forniceal foreshortening in cases of progressive cicatrising conjunctivitis (PCC) is important in ascertaining disease stage and progression. Lower fornix shortening is often documented subjectively or semi-objectively, whereas upper forniceal obliteration is seldom quantified. Although tools such as fornix depth measurers (FDMs) have been described, their designs limit upper fornix measurement. The purpose of this study was to custom-design a FDM to evaluate the upper fornix and to assess variability in gauging fornix depth. \ud \ud Methods A polymethylmethacrylate FDM was constructed using industry-standard jewellery computer software and machinery. Two observers undertook a prospective independent evaluation of central lower fornix depth in a heterogeneous cohort of patients with clinically normal and abnormal conjunctival fornices both subjectively and by using the FDM (in mm). Upper central fornix depth was also measured. Agreement was assessed using Bland–Altman plots. \ud \ud Results Fifty-one eyes were evaluated. There was 100% intraobserver agreement to within 1 mm for each observer for lower fornix measurement. The mean difference in fornix depth loss using the FDM between observer 1 and 2 was 1.19%, with 95% confidence of agreement (±2SD) of −15% to +20%. In total, 86% (44/51) of measurements taken by the two observers agreed to within 10% of total lower fornix depth (ie, ±1 mm) versus only 63% (32/51) of the subjective measurements. Mean upper fornix difference was 0.57 mm, with 95% confidence of agreement of between −2 and + 3 mm. \ud \ud Conclusions This custom-designed FDM is well tolerated by patients and shows low intraobserver and interobserver variability. This enables repeatable and reproducible measurement of upper and lower fornix depths, facilitating improved rates of detection and better monitoring of progression of conjunctival scarring

Health-related quality of life and Chlamydia trachomatis infection in sexually experienced female inner-city students: a community-based cross-sectional study.

This cross-sectional study was undertaken to compare health-related quality of life (EQ-5D) in women with and without undiagnosed Chlamydia trachomatis infection. We analysed data from 2401 multi-ethnic sexually active female students aged 16-27 years who were recruited to a randomised controlled trial of chlamydia screening - the prevention of pelvic infection trial in 2004-2006. At recruitment, all participants were asked to provide self-taken vaginal swabs for chlamydia testing and to complete a sexual health questionnaire including quality of life (EQ-5D). Most women (69%) had an EQ-5D of one representing 'perfect health' in the five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. We therefore compared the proportion of women with an EQ-5D score < 1 implying 'less than perfect health' in women with and without chlamydia infection, and women with symptomatic chlamydia versus the remainder. The proportion of women with EQ-5D score < 1 was similar in women with and without undiagnosed chlamydia: 34% (47/138) versus 31% (697/2263; RR 1.11, 95% CI 0.87 to 1.41). However, more women with symptomatic chlamydia had EQ-5D score < 1 than the remainder: 45% (25/55) versus 31% (714/2319; RR 1.47, CI 1.10 to 1.98). In this community-based study, EQ-5D scores were similar in women with and without undiagnosed chlamydia. However, a higher proportion of women with symptomatic chlamydia infection had 'less than perfect health'. Undiagnosed chlamydia infection may not have a major short-term effect on health-related quality of life, but EQ-5D may not be the best tool to measure it in this group

Wetting of Curved Surfaces

As a first step towards a microscopic understanding of the effective interaction between colloidal particles suspended in a solvent we study the wetting behavior of one-component fluids at spheres and fibers. We describe these phenomena within density functional theory which keeps track of the microscopic interaction potentials governing these systems. In particular we properly take into account the power-law decay of both the fluid-fluid interaction potentials and the substrate potentials. The thicknesses of the wetting films as a function of temperature and chemical potential as well as the wetting phase diagrams are determined by minimizing an effective interface potential which we obtain by applying a sharp-kink approximation to the density functional. We compare our results with previous approaches to this problem.Comment: 54 pages, 17 figures, accepted for publication in Physica