328 research outputs found

    Condition monitoring approach for permanent magnet synchronous motor drives based on the INFORM method

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    This paper proposes a monitoring scheme based on saliency tracking to assess the health condition of PMSM drives operating under non stationary conditions. The evaluated scheme is based on the INFORM methodology, which is associated to the accurate sensorless control of PM drives without zero speed limitation. The result is a monitoring scheme that is able to detect faults that would be very difficult to evaluate under nonstationary conditions. A relevant aspect of the proposed scheme is that it remains valid for full speed range, and can be used for standstill operation. Additionally, the approach is insensitive to the inverter nonlinearities which enhance the detection capabilities further respect to similar topologies. In this work the proposed approach is evaluated numerically and experimentally in the presence of incipient winding faults and inter-turn short circuits in a PM conventional drive. The obtained results show quick response and excellent detection capabilities not only in the detection of faults, but to determine their magnitude which is vital to avoid further degradation

    Evidence for Negative Effects of Elevated Intra-Abdominal Pressure on Pulmonary Mechanics and Oxidative Stress

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    Objective. To compare the effects of pneumoperitoneum on lung mechanics, end-tidal CO2 (ETCO2), arterial blood gases (ABG), and oxidative stress markers in blood and bronchoalveolar lavage fluid (BALF) during laparoscopic cholecystectomy (LC) by using lung-protective ventilation strategy. Materials and Methods. Forty-six patients undergoing LC and abdominal wall hernia (AWH) surgery were assigned into 2 groups. Measurements and blood samples were obtained before, during pneumoperitoneum, and at the end of surgery. BALF samples were obtained after anesthesia induction and at the end of surgery. Results. Peak inspiratory pressure, ETCO2, and pCO2 values at the 30th minute were significantly increased, while there was a significant decrease in dynamic lung compliance, pH, and pO2 values in LC group. In BALF samples, total oxidant status (TOS), arylesterase, paraoxonase, and malondialdehyde levels were significantly increased; the glutathione peroxidase levels were significantly decreased in LC group. The serum levels of TOS and paraoxonase were significantly higher at the end of surgery in LC group. In addition, arylesterase level in the 30th minute was increased compared to baseline. Serum paraoxonase level at the end of surgery was significantly increased when compared to AWH group. Conclusions. Our study showed negative effects of pneumoperitoneum in both lung and systemic levels despite lung-protective ventilation strategy

    Advice or exercise for chronic whiplash disorders? Design of a randomized controlled trial

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    BACKGROUND: Whiplash-associated disorder (or "whiplash") is a common condition incurring considerable expense in social and economic terms. A lack of research on effective therapy for patients with chronic whiplash associated disorders prompted the design of the current study. The primary aim of this randomised controlled trial is to determine the effects of a physical activity program for people with chronic (symptoms of > 3 months duration) whiplash. A secondary aim is to determine if pain severity, level of disability and fear of movement/(re)injury predict response to a physical activity program. METHODS / DESIGN: This paper presents the rationale and design of a randomised controlled trial examining the effects of advice and individualized sub-maximal exercise programs in the treatment of whiplash associated disorders. DISCUSSION: This paper highlights the design, methods and operational aspects of a significant clinical trial in the area of whiplash and chronic pain

    The lived experience of breathlessness and its implications for care: a qualitative comparison in cancer, COPD, heart failure and MND

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    <p>Abstract</p> <p>Background</p> <p>Breathlessness is one of the core symptoms, particularly persistent and frequent, towards the end of life. There is no evidence of how the experience of breathlessness differs across conditions. This paper compares the experience of breathlessness in cancer, COPD, heart failure and MND, four conditions sharing heavy symptom burdens, poor prognoses, high breathlessness rates and palliative care needs.</p> <p>Methods</p> <p>For this qualitative study a purposive sample of 48 patients was included with a diagnosis of cancer (10), COPD (18), heart failure (10) or MND (10) and experiencing daily problems of breathlessness. Patients were recruited from the respective clinics at the hospital; specialist nurses' ward rounds and consultations, and "Breathe Easy" service users meetings in the community. Data were collected through semi-structured, in-depth interviews and participant observation. Breathlessness was compared according to six components derived from explanatory models and symptom schemata, first within groups and then across groups. Frequency counts were conducted to check the qualitative findings.</p> <p>Results</p> <p>All conditions shared the disabling effects of breathlessness. However there were differences between the four conditions, in the specific constraints of the illness and patients' experiences with the health care context and social environment. In cancer, breathlessness signalled the (possible) presence of cancer, and functioned as a reminder of patients' mortality despite the hopes they put in surgery, therapies and new drugs. For COPD patients, breathlessness was perceived as a self-inflicted symptom. Its insidious nature and response from services disaffirmed their experience and gradually led to greater disability in the course of illness. Patients with heart failure perceived breathlessness as a contributing factor to the negative effects of other symptoms. In MND breathlessness meant that the illness was a dangerous threat to patients' lives. COPD and heart failure had similar experiences.</p> <p>Conclusion</p> <p>Integrated palliative care is needed, that makes use of all appropriate therapeutic options, collaborative efforts from health, social care professionals, patients and caregivers, and therapies that acknowledge the dynamic interrelation of the body, mind and spirit.</p

    Genome-wide association reveals three SNPs associated with sporadic amyotrophic lateral sclerosis through a two-locus analysis

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    <p>Abstract</p> <p>Background</p> <p>Amyotrophic lateral sclerosis (ALS) is a fatal, degenerative neuromuscular disease characterized by a progressive loss of voluntary motor activity. About 95% of ALS patients are in "sporadic form"-meaning their disease is not associated with a family history of the disease. To date, the genetic factors of the sporadic form of ALS are poorly understood.</p> <p>Methods</p> <p>We proposed a two-stage approach based on seventeen biological plausible models to search for two-locus combinations that have significant joint effects to the disease in a genome-wide association study (GWAS). We used a two-stage strategy to reduce the computational burden associated with performing an exhaustive two-locus search across the genome. In the first stage, all SNPs were screened using a single-marker test. In the second stage, all pairs made from the 1000 SNPs with the lowest p-values from the first stage were evaluated under each of the 17 two-locus models.</p> <p>Results</p> <p>we performed the two-stage approach on a GWAS data set of sporadic ALS from the SNP Database at the NINDS Human Genetics Resource Center DNA and Cell Line Repository <url>http://ccr.coriell.org/ninds/</url>. Our two-locus analysis showed that two two-locus combinations--rs4363506 (SNP1) and rs3733242 (SNP2), and rs4363506 and rs16984239 (SNP3) -- were significantly associated with sporadic ALS. After adjusting for multiple tests and multiple models, the combination of SNP1 and SNP2 had a p-value of 0.032 under the Dom∩Dom epistatic model; SNP1 and SNP3 had a p-value of 0.042 under the Dom × Dom multiplicative model.</p> <p>Conclusion</p> <p>The proposed two-stage analytical method can be used to search for joint effects of genes in GWAS. The two-stage strategy decreased the computational time and the multiple testing burdens associated with GWAS. We have also observed that the loci identified by our two-stage strategy can not be detected by single-locus tests.</p

    Two-photon dual imaging platform for in vivo monitoring cellular oxidative stress in liver injury

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    Oxidative stress reflects an imbalance between reactive oxygen species (ROS) and antioxidants, which has been reported as an early unifying event in the development and progression of various diseases and as a direct and mechanistic indicator of treatment response. However, highly reactive and short-lived nature of ROS and antioxidant limited conventional detection agents, which are influenced by many interfering factors. Here, we present a two-photon sensing platform for in vivo dual imaging of oxidative stress at the single cell-level resolution. This sensing platform consists of three probes, which combine the turn-on fluorescent transition-metal complex with different specific responsive groups for glutathione (GSH), hydrogen peroxide (H2O2) and hypochlorous acid (HOCl). By combining fluorescence intensity imaging and fluorescence lifetime imaging, these probes totally remove any possibility of crosstalk from in vivo environmental or instrumental factors, and enable accurate localization and measurement of the changes in ROS and GSH within the liver. This precedes changes in conventional biochemical and histological assessments in two distinct experimental murine models of liver injury. The ability to monitor real-time cellular oxidative stress with dual-modality imaging has significant implications for high-accurate, spatially configured and quantitative assessment of metabolic status and drug response

    A systems perspective on the death of a car company

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    Purpose – The aim of this paper is to understand how large and apparently successful organizations enter spirals of decline that are very difficult to reverse. The paper examines the case of Rover, once one of the largest car producers in the world, which collapsed in 2005. An analysis of strategic and operational choices made over a period of 40 years investigates the reasons for, and consequences of, a growing mismatch between the context faced by the company (industry dynamics, market conditions) and its operational capabilities, a mismatch that ultimately brought about the company's demise. Design/methodology/approach – The paper is based on interviews with 32 people, including senior managers (including four chief executives), government ministers and union officials who were key decision makers within, or close to, the company during the period 1968 and 2005. Secondary sources and documentary evidence (e.g. production and sales data) are used to build up a historical picture of the company and to depict its deteriorating financial and market position from 1968 onwards. Findings – The company was formed from a multitude of previously independent firms as part of a government‐sponsored agenda to build a UK National Champion in the car industry. The merged company failed due to several factors including poor product development processes, poor manufacturing performance, difficult labour relations, a very wide product portfolio and a lack of financial control. Although strenuous efforts were made to address those issues, including periods of whole or part ownership by British Aerospace, Honda and BMW, the company's position deteriorated until eventually production volumes were too low for viable operation. Practical implications – The case of Rover highlights the importance of what has been termed “the management unit” in complex systems. The management unit comprises processes and routines to deal with challenges such as managing product portfolios, connecting strategic and operational choices, and scanning and responding to the environment. In the case of Rover, a number of factors taken together generated excessive load on a management unit frequently operating under conditions of resource scarcity. We conclude that viewing corporate failure from a systems perspective, rather than in terms of shortcomings in specific subsystems, such as manufacturing or product development, yields insights often absent in the operations management literature. Originality/value – The paper is of value by showing corporate failure from a systems perspective, rather than in terms of shortcomings in specific subsystems, such as manufacturing or product development; and yields insights often absent in the operations management literature. The Rover case featured in the paper demonstrates the usefulness of systems ideas to understanding at least some types of failure, not as an alterative to capability‐based approaches, but in addition to them

    Policy making under uncertainty in electric vehicle demand

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    The introduction of electric vehicles (EVs) into the passenger vehicle market has, in recent years, become viewed as a primary solution to the significant carbon dioxide emissions attributed to personal mobility. Moreover, EVs offer a means by which energy diversification and efficiency can be improved compared to the current system. The UK government and European Commission have played an active role in steering the development and market introduction of EVs. However, a great deal of uncertainty remains regarding the effectiveness of these policies and the viability of EV technology in the mainstream automotive market. This paper investigates the prevalence of uncertainty concerning the demand for EVs. This is achieved through the application of a conceptual framework that assesses the locations of uncertainty. UK and EU documents are assessed through a review of the published policy alongside contributions from academia to determine how uncertainty has been reduced. This assessment offers insights to decision makers in this area by evaluating the work done to date through a landscape analysis. Results have identified six different locations of uncertainty covering: consumer, policy, infrastructure, technical, economic and social issues

    Protocol of a randomized controlled trial of the effectiveness of physician education and activation versus two rehabilitation programs for the treatment of Whiplash-associated Disorders: The University Health Network Whiplash Intervention Trial

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    Background: Whiplash injuries are an important public health problem that is associated with significant disability and high health care utilization. Recent cohort studies suggest that physician care may be the most effective treatment for patients with whiplash-associated disorders. However, these findings have not been tested in a randomized controlled trial. The purpose of this study is to determine which of physician care or two rehabilitation programs of care is most effective in improving recovery of patients with recent whiplash associated disorders. Methods and Design: We designed a pragmatic randomized clinical trial. A total of 444 participants (148 in each of three arms) who reside in Southern Ontario, Canada will be recruited from a large insurer. We will include individuals who are 18 years of age or older and who are diagnosed with Grade I or II Whiplash-associated Disorders. Participants will be randomized to physician-based education and activation or one of two rehabilitation programs of care currently in use in Ontario. Our primary outcome, self-rated global recovery and all secondary outcomes (neck pain intensity, whiplash disability, health-related quality of life, depressive symptomatology and satisfaction with care) will be measured at baseline by a trial coordinator and at 6 weeks, 3, 6, 9 and 12 months follow-up by an interviewer who is blind to the participants' baseline characteristics and treatment allocation. We will also collect information on general health status, other injuries, comorbidities, expectation of recovery, work status, pain coping, legal representation, and co-interventions. The primary intention-to-treat analysis will compare time to recovery between the three interventions. This trial will have 90% power at an alpha of 0.05 to detect a 20% difference in the rate of perceived recovery at one year. Secondary analyses will compare the health outcomes, rate of recurrence and the rate of adverse events between intervention groups. Conclusion: The results of this study will provide the public, clinicians and policy makers much needed evidence on the effectiveness of common approaches used to manage whiplash-associated disorders. © 2008 Côté et al; licensee BioMed Central Ltd

    Comment letters to the National Commission on Commission on Fraudulent Financial Reporting, 1987 (Treadway Commission) Vol. 1

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    https://egrove.olemiss.edu/aicpa_sop/1661/thumbnail.jp
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