59 research outputs found

    Can exercise limits prevent post-exertional malaise in chronic fatigue syndrome? An uncontrolled clinical trial.

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    <b>Objective</b>: It was hypothesized that the use of exercise limits prevents symptom increases and worsening of their health status following a walking exercise in people with Chronic Fatigue Syndrome (CFS). <b>Design</b>: An uncontrolled clinical trial (semi-experimental design). <b>Setting</b>: Outpatient clinic of a university department. <b>Subjects</b>: 24 patients with CFS. <b>Interventions</b>: Subjects undertook a walking test with the two concurrent exercise limits. Each subject walked at an <i>intensity</i> where the maximum heart rate was determined by heart rate corresponding to the respiratory exchange ratio =1.0 derived from a previous sub-maximal exercise test and for a duration calculated from how long each patient felt they were able to walk. <b>Main outcome measures</b>: The Short Form 36 Health Survey or SF-36, the CFS Symptom List, and the CFS-Activities and Participation Questionnaire were filled in prior to, immediately and 24 hours post-exercise. <b>Results</b>: The fatigue increase observed immediately post-exercise (p=0.006) returned to pre-exercise levels 24 hours post-exercise. The increase in pain observed immediately post-exercise was retained at 24 hours post-exercise (p=0.03). Fourteen of 24 subjects experienced a clinically meaningful change in bodily pain (change of SF-36 bodily pain score ³10). Six of 24 participants indicated that the exercise bout had slightly worsened their health status, and 2 of 24 had a clinically meaningful decrease in vitality (change of SF-36 vitality score ³20). There was no change in activity limitations/participation restrictions. <b>Conclusion</b>: It was shown that the use of exercise limits (limiting both the intensity and duration of exercise) prevents important health status changes following a walking exercise in people with CFS, but was unable to prevent short-term symptom increases

    Martensitic transition and magnetoresistance in a Cu-Al-Mn shape memory alloy. Influence of aging

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    We have studied the effect of ageing within the miscibility gap on the electric, magnetic and thermodynamic properties of a non-stoichiometric Heusler Cu-Al-Mn shape-memory alloy, which undergoes a martensitic transition from a bccbcc-based (β\beta-phase) towards a close-packed structure (MM-phase). Negative magnetoresistance which shows an almost linear dependence on the square of magnetization with different slopes in the MM- and β\beta-phases, was observed. This magnetoresistive effect has been associated with the existence of Mn-rich clusters with the Cu2_2AlMn-structure. The effect of an applied magnetic field on the martensitic transition has also been studied. The entropy change between the β\beta- and MM-phases shows negligible dependence on the magnetic field but it decreases significantly with annealing time within the miscibility gap. Such a decrease is due to the increasing amount of Cu2_2MnAl-rich domains that do not transform martensitically.Comment: 9 pages, 9 figures, accepted for publication in PR

    How do firms comply with international sustainability standards? Processes and consequences of adopting the global reporting initiative

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    This paper addresses the issue of the influence of global governance institutions, particularly international sustainability standards, on a firm’s intra-organizational practices. More precisely, we provide an exploratory empirical view of the impact of the Global Reporting Initiative (GRI) on a multinational corporation’s (MNC) corporate social responsibility (CSR) management practices. We investigate standard compliance by comparing the stated intention of the use of the GRI with its actual use and the consequent effects within the firm. Based on an in-depth case study, our findings illustrate the processes and consequences of the translation of the GRI within the organization. We show that substantive standard adoption can lead to unintended consequences on CSR management practices, specifically it can influence the management structure and CSR committee function; the choice of CSR activities, the relationships between subsidiaries, the temporal dimension of CSR management, and the interpretation of CSR performance. We also highlight the need to look at the relationship dynamics (or lack of) between standards. Finally we illustrate and discuss the role of reporting and its influence on management in order to better understand the internal issues arising from compliance with standards

    Kinetics of martensitic transitions in Cu-Al-Mn under thermal cycling: Analysis at multiple length scales

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    In this paper we study the evolution of the kinetic features of the martensitic transition in a Cu-Al-Mn single crystal under thermal cycling. The use of several experimental techniques including optical microscopy, calorimetry, and acoustic emission, has enabled us to perform an analysis at multiple scales. In particular, we have focused on the analysis of avalanche events (associated with the nucleation and growth of martensitic domains), which occur during the transition. There are significant differences between the kinetics at large and small length scales. On the one hand, at small length scales, small avalanche events tend to sum to give new larger events in subsequent loops. On the other hand, at large length scales the large domains tend to split into smaller ones on thermal cycling. We suggest that such different behavior is the necessary ingredient that leads the system to the final critical state corresponding to a power-law distribution of avalanches

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    Anharmonicity of Cu-based shape-memory alloys in the vicinity of their martensitic transition

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    The anharmonicity in solid crystals due to the nonlinearity of interatomic forces with respect to atomic displacements, is the origin of many important thermodynamic properties of crystals such as the thermal expansion or the deviation of the lattice specific heat at high temperatures with respect to Debye contribution. Moreover, the anharmonic nature of lattice vibrations in crystals plays an essential role in determining the lattice dynamics in the vicinity of structural phase transitions..
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