743 research outputs found

    Comparison of ionospheric electric currents and plasma convection patterns observed during substorms

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    Abstract. The effect of magnetospheric substorms on the global ionospheric convection pattern is widely debated. Discussed here, is a study made of ionospheric electric currents, co-incident with plasma convection at the time of substorm onset, using the HF radars of the Super Dual Auroral Radar Network (SuperDARN), and the global array of ground magnetometers. Preliminary results are presented, which utilise an ionospheric potential mapping model to produce plasma convection vectors and electric potential contours, with corresponding ionospheric currents being derived from magnetic perturbations. Clear indications of a relationship between the substorm current system and the plasma convection patterns are seen. 1

    Exercise interventions for people undergoing multimodal cancer treatment that includes surgery

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    This is the protocol for a review and there is no abstract. The objectives are as follows: To determine the effect of exercise interventions for people undergoing multimodal treatment including surgery on physical fitness, safety and feasibility, health-related quality of life and other important health outcomes

    Nightside ionospheric convection asymmetries during the early substorm expansion phase: relationship to onset local time

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    We present SuperDARN radar observations of ionospheric convection during substorms. Substorms were grouped according to their onset latitude, onset magnetic local time, and the prevailing sense of IMF BY. The radar observations were then sorted according to substorm group and average convection patterns produced. Here, we discuss the patterns corresponding to substorms with onsets occurring in the 65∘−67∘ onset latitude range, at either early (20 − 22h) or late (01 − 03h) magnetic local times, during intervals of either dominant positive or negative IMF BY. We show that the morphology of the convection patterns differs from that predicted by existing empirical models, with the location of the nightside convection throat being largely consistent with the location of substorm onset. The expected IMF BY-induced dawn-dusk convection asymmetry can be enhanced on the nightside when the substorm onset occurs at a fortuitous location, but can equally be removed or even reversed from this expected state. Thus the nightside convection asymmetries are seemingly unrelated to the instantaneous sense of IMF BY

    Physical activity levels in locally advanced rectal cancer patients following neoadjuvant chemoradiotherapy and an exercise training programme before surgery: a pilot study

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    Background: The aim of this pilot study was to measure changes in physical activity level (PAL) variables, as well as sleep duration and efficiency in people with locally advanced rectal cancer (1) before and after neoadjuvant chemoradiotherapy (CRT) and (2) after participating in a pre-operative 6-week in-hospital exercise training programme, following neoadjuvant CRT prior to major surgery, compared to a usual care control group.Methods: We prospectively studied 39 consecutive participants (27 males). All participants completed standardised neoadjuvant CRT: 23 undertook a 6-week in-hospital exercise training programme following neoadjuvant CRT. These were compared to 16 contemporaneous non-randomised participants (usual care control group). All participants underwent a continuous 72-h period of PA monitoring by SenseWear biaxial accelerometer at baseline, immediately following neoadjuvant CRT (week 0), and at week 6 (following the exercise training programme).Results: Of 39 recruited participants, 23 out of 23 (exercise) and 10 out of 16 (usual care control) completed the study. In all participants (n = 33), there was a significant reduction from baseline (pre-CRT) to week 0 (post-CRT) in daily step count: median (IQR) 4966 (4435) vs. 3044 (3265); p < 0.0001, active energy expenditure (EE) (kcal): 264 (471) vs. 154 (164); p = 0.003, and metabolic equivalent (MET) (1.3 (0.6) vs. 1.2 (0.3); p = 0.010). There was a significant improvement in sleep efficiency (%) between week 0 and week 6 in the exercise group compared to the usual care control group (80 (13) vs. 78 (15) compared to (69 ((24) vs. 76 (20); p = 0.022), as well as in sleep duration and lying down time (p < 0.05) while those in active EE (kcal) (152 (154) vs. 434 (658) compared to (244 (198) vs. 392 (701) or in MET (1.3 (0.4) vs. 1.5 (0.5) compared to (1.1 (0.2) vs. 1.5 (0.5) were also of importance but did not reach statistical significance (p > 0.05). An apparent improvement in daily step count and overall PAL in the exercise group was not statistically significant.Conclusions: PAL variables, daily step count, EE and MET significantly reduced following neoadjuvant CRT in all participants. A 6-week pre-operative in-hospital exercise training programme improved sleep efficiency, sleep duration and lying down time when compared to participants receiving usual care

    Characteristics of medium-scale travelling ionospheric disturbances observed near the Antarctic Peninsula by HF radar

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    We present a survey of medium-scale traveling ionospheric disturbances (MSTIDs) observed by a Super Dual Auroral Radar Network HF radar located in the Falkland Islands between May 2010 and April 2011. The radar has a field of view that overlooks the Antarctic Peninsula, a known hot spot of gravity wave activity. We present observations of radar ground-backscatter data, in which the signatures of MSTIDs are manifested as structured enhancements in echo power. Observed periods were in the range 30–80 min, corresponding to frequencies of 0.2–0.6 mHz. Wavelengths were generally in the range 200–800 km and phase speeds in the range 100–300 m s−1. These values are within the ranges typically associated with medium-scale gravity waves. We find a primary population of northward (equatorward) propagating MSTIDs, which demonstrate an association with enhanced solar wind-magnetosphere coupling and a smaller, westward propagating population, that could be associated with atmospheric gravity waves excited by winds over the Andean and Antarctic Peninsula mountains or by the high winds of the Antarctic Polar Vortex

    Reformers and revolutionaries: the battle for the working classes in Gibraltar and its hinterland, 1902-1921

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    This article examines labour organisation in Gibraltar and its hinterland from c.1902-1921. It demonstrates that the traditionally strong links which had existed between organisations in Gibraltar and neighbouring Spain - links based upon a shared belief in anarchist ideas and practices - had, by 1921, broken down due to the adoption of gradualist and constitutionalist politics and industrial relations by workers on the Rock. Two principal agents drove this change. First, in 1919, the British Workers’ Union established a branch in Gibraltar which successfully worked to establish itself as principal negotiator and representative of workers on the Rock. Second, a reforming governor in Gibraltar undertook to open up political spaces in Gibraltar which offered the potential to work with, rather than against, the state in the colony. By the end of the period, anarchism, and anarchist ideas, were not extinguished in Gibraltar, but they would never again serve as the inspiration for industrial and political campaigns on the Rock, much to the delight of both Gibraltarian employers and the British colonial authorities. This case-study invites further consideration of how British style trade union activity in the empire displaced indigenous forms of organising, a subject which has heretofore received scant attention

    Exercise rehabilitation following intensive care unit discharge for recovery from critical illness: executive summary of a Cochrane Collaboration systematic review

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    Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society of Sarcopenia, Cachexia and Wasting DisordersSkeletal muscle wasting and weakness are major complications of critical illness and underlie the profound physical and functional impairments experienced by survivors after discharge from the intensive care unit (ICU). Exercise-based rehabilitation has been shown to be beneficial when delivered during ICU admission. This review aimed to determine the effectiveness of exercise rehabilitation initiated after ICU discharge on primary outcomes of functional exercise capacity and health-related quality of life. We sought randomized controlled trials, quasi-randomized controlled trials, and controlled clinical trials comparing an exercise intervention commenced after ICU discharge vs. any other intervention or a control or ‘usual care’ programme in adult survivors of critical illness. Cochrane Central Register of Controlled Trials, Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica Database, and Cumulative Index to Nursing and Allied Health Literature databases were searched up to February 2015. Dual, independent screening of results, data extraction, and quality appraisal were performed. We included six trials involving 483 patients. Overall quality of evidence for both outcomes was very low. All studies evaluated functional exercise capacity, with three reporting positive effects in favour of the intervention. Only two studies evaluated health-related quality of life and neither reported differences between intervention and control groups. Meta-analyses of data were precluded due to variation in study design, types of interventions, and selection and reporting of outcome measurements. We were unable to determine an overall effect on functional exercise capacity or health-related quality of life of interventions initiated after ICU discharge for survivors of critical illness. Findings from ongoing studies are awaited. Future studies need to address methodological aspects of study design and conduct to enhance rigour, quality, and synthesis

    Multi‐instrument Observations of Ion‐Neutral Coupling in the Dayside Cusp

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    Using data from the Scanning Doppler Imager, the Super Dual Auroral Radar Network, the EISCAT Svalbard Radar and an auroral all‐sky imager, we examine an instance of F‐region neutral winds which have been influenced by the presence of poleward moving auroral forms near the dayside cusp region. We observe a reduction in the time taken for the ion‐drag force to re‐orientate the neutrals into the direction of the convective plasma (on the order of minutes), compared to before the auroral activity began. Additionally, because the ionosphere near the cusp is influenced much more readily by changes in the solar wind via dayside reconnection, we observe the neutrals responding to an interplanetary magnetic field change within minutes of it occurring. This has implications on the rate that energy is deposited into the ionosphere via Joule heating, which we show to become dampened by the neutral winds
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