250 research outputs found

    Dissipation in intercluster plasma

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    We discuss dissipative processes in strongly gyrotropic, nearly collisionless plasma in clusters of galaxies (ICM). First, we point out that Braginsky theory, which assumes that collisions are more frequent that the system's dynamical time scale, is inapplicable to fast, sub-viscous ICM motion. Most importantly, the electron contribution to collisional magneto-viscosity dominates over that of ions for short-scale Alfvenic motions. Thus, if a turbulent cascade develops in the ICM and propagates down to scales 1\leq 1 kpc, it is damped collisionally not on ions, but on electrons. Second, in high beta plasma of ICM, small variations of the magnetic field strength, of relative value 1/β\sim 1/\beta, lead to development of anisotropic pressure instabilities (firehose, mirror and cyclotron). Unstable wave modes may provide additional resonant scattering of particles, effectively keeping the plasma in a state of marginal stability. We show that in this case the dissipation rate of a laminar, subsonic, incompressible flows scales as inverse of plasma beta parameter. We discuss application to the problem of ICM heating.Comment: 4 pages, accepted by ApJ Let

    Physical Acoustics

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    Contains reports on three research projects.U. S. Navy (Office of Naval Research) under Contract Nonr-1841(42

    Education and older adults at the University of the Third Age

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    This article reports a critical analysis of older adult education in Malta. In educational gerontology, a critical perspective demands the exposure of how relations of power and inequality, in their myriad forms, combinations, and complexities, are manifest in late-life learning initiatives. Fieldwork conducted at the University of the Third Age (UTA) in Malta uncovered the political nature of elder-learning, especially with respect to three intersecting lines of inequality - namely, positive aging, elitism, and gender. A cautionary note is, therefore, warranted at the dominant positive interpretations of UTAs since late-life learning, as any other education activity, is not politically neutral.peer-reviewe

    Desperately seeking a cure: Treatment seeking and appraisal in irritable bowel syndrome

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    © 2018 The British Psychological Society Objectives: Irritable bowel syndrome (IBS) is common and adversely affects patients' quality of life. Multiple potential treatment options exist for patients (and clinicians) to choose from, with limited evidence to inform treatment selection. The aim was to explore how patients with IBS go about seeking and appraising different treatment modalities, with a view to elucidating the psychological processes involved and identifying opportunities to improve clinical practice. Design: Qualitative study nested within a randomized controlled trial of therapist-delivered and web-based cognitive behavioural therapy versus treatment-as-usual for IBS. Methods: A total of 52 people participated in semi-structured interviews about their prior experiences of treatments for IBS. Transcripts were analysed using inductive thematic analysis. Results: Key themes (desperation for a cure, disappointment at lack of cure, appraising the effects of diverse treatments, and hope for positive effects) clustered around an overarching theme of being trapped within a vicious cycle of hope and despair on treatment seeking. A desperation and willingness drove interviewees to try any treatment modality available that might potentially offer relief. Coming to accept there is no cure for IBS helped interviewees escape the vicious cycle. Treatments were appraised for their effects on symptoms and quality of life while also considering, but rarely prioritizing, other aspects including convenience of the regimen itself, whether it addressed the perceived root causes of IBS, perceived side-effects, and cost. Conclusion: Treatment seeking in IBS can be challenging for patients. Supportive discussions with health care professionals about illness perceptions, treatment beliefs, and goals could improve patients' experiences. Statement of contribution What is already known on this subject? Irritable bowel syndrome (IBS) is a highly prevalent chronic relapsing functional gastrointestinal disorder. Studies show few treatment modalities provide complete symptom relief. IBS is associated with emotional and physical distress, and negatively impacts personal, social, and professional aspects of quality of life. What does this study add? Patients appraise IBS treatments for impact on quality of life and treatment characteristics. Developing acceptance and coping strategies helps escape treatment-seeking vicious cycles of hope and despair. Clinicians could better support patients by discussing their illness perceptions, treatment goals, and values

    A centralised public information resource for randomised trials: a scoping study to explore desirability and feasibility

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    BACKGROUND: There are currently several concerns about the ways in which people are recruited to participate in randomised controlled trials, the low acceptance rates among people invited to participate, and the experiences of trial participants. An information resource about on-going clinical trials designed for potential and current participants could help overcome some of these problems. METHODS: We carried out a scoping exercise to explore the desirability and feasibility of establishing such a resource. We sought the views of a range of people including people who were considering taking part in a trial, current trial participants, people who had been asked but refused to participate in a trial, consumer group representatives and researchers who design and conduct trials. RESULTS: There was broad-based support for the concept of a centralised information resource for members of the public about on-going and recently completed clinical trials. Such an information resource could be based on a database containing standardised information for each trial relating to the purpose of the trial; the interventions being compared; the implications of participation for participants; and features indicative of scientific quality and ethical probity. The usefulness of the database could be enhanced if its search facility could allow people to enter criteria such as a disease and geographic area and be presented with all the trials relevant to them, and if optional display formats could allow them to view information in varying levels of detail. Access via the Internet was considered desirable, with complementary supported access via health information services. The development of such a resource is technically feasible, but the collation of the required information would take a significant investment of resources. CONCLUSION: A centralised participant oriented information resource about clinical trials could serve several purposes. A more detailed investigation of its feasibility and exploration of its potential impacts are required

    CAM therapies among primary care patients using opioid therapy for chronic pain

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    <p>Abstract</p> <p>Background</p> <p>Complementary and alternative medicine (CAM) is an increasingly common therapy used to treat chronic pain syndromes. However; there is limited information on the utilization and efficacy of CAM therapy in primary care patients receiving long-term opioid therapy.</p> <p>Method</p> <p>A survey of CAM therapy was conducted with a systematic sample of 908 primary care patients receiving opioids as a primary treatment method for chronic pain. Subjects completed a questionnaire designed to assess utilization, efficacy and costs of CAM therapies in this population.</p> <p>Results</p> <p>Patients were treated for a variety of pain problems including low back pain (38.4%), headaches (9.9%), and knee pain (6.5%); the average duration of pain was 16 years. The median morphine equivalent opioid dose was 41 mg/day, and the mean dose was 92 mg/day. Forty-four percent of the sample reported CAM therapy use in the past 12 months. Therapies utilized included massage therapy (27.3%, n = 248), chiropractic treatment (17.8%, n = 162), acupuncture (7.6%, n = 69), yoga (6.1%, n = 55), herbs and supplements (6.8%, n = 62), and prolotherapy (5.9%, n = 54). CAM utilization was significantly related to age female gender, pain severity income pain diagnosis of neck and upper back pain, and illicit drug use. Medical insurance covered chiropractic treatment (81.8%) and prolotherapy (87.7%), whereas patients primarily paid for other CAM therapies. Over half the sample reported that one or more of the CAM therapies were helpful.</p> <p>Conclusion</p> <p>This study suggests CAM therapy is widely used by patients receiving opioids for chronic pain. Whether opioids can be reduced by introducing such therapies remains to be studied.</p

    Harpgophytum procumbens for osteoarthritis and low back pain: A systematic review

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    BACKGROUND: The objective of this review is to determine the effectiveness of Harpagophytum procumbens preparations in the treatment of various forms of musculoskeletal pain. METHODS: Several databases and other sources were searched to identify randomized controlled trials, quasi-randomized controlled trials, and controlled clinical trials testing Harpagophytum preparations in adults suffering from pain due to osteoarthritis or low back pain. RESULTS: Given the clinical heterogeneity and insufficient data for statistical pooling, trials were described in a narrative way, taking into consideration methodological quality scores. Twelve trials were included with six investigating osteoarthritis (two were identical trials), four low back pain, and three mixed-pain conditions. CONCLUSIONS: There is limited evidence for an ethanolic Harpagophytum extract containing less than <30 mg harpagoside per day in the treatment of knee and hip osteoarthritis. There is moderate evidence of effectiveness for (1) the use of a Harpagophytum powder at 60 mg harpagoside in the treatment of osteoarthritis of the spine, hip and knee; (2) the use of an aqueous Harpagophytum extract at a daily dose of 100 mg harpagoside in the treatment of acute exacerbations of chronic non-specific low back pain; and (3) the use of an aqueous extract of Harpagophytum procumbens at 60 mg harpagoside being non-inferior to 12.5 mg rofecoxib per day for chronic non-specific low-back pain (NSLBP) in the short term. Strong evidence exists for the use of an aqueous Harpagophytum extract at a daily dose equivalent of 50 mg harpagoside in the treatment of acute exacerbations of chronic NSLBP

    Plasmas and Controlled Nuclear Fusion

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    Contains research objectives and reports on three research projects.National Science Foundation (Grant GK-1165)National Science Foundation (Grant GK-57
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