301 research outputs found

    Exercise training versus angioplasty for stable claudication. Long and medium term results of a prospective, randomised trial

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    Objectives:To compare percutaneous transluminal angioplsty (PTA) against exercise training in the treatment of stable claudication.Design:Prospective, randomised trial.Materials:Fifty-six patients with unilateral, stable, lower limb claudication assessed prior to randomisation, at 3 monthly intervals for 15 months, and at approximately 6 years follow-up. Thirty-seven patients were available for long term review.Outcome measures:Ankle/brachial pressure index (ABPI), treadmill claudication and maximum walking distances, percentage fall in ankle systolic pressure after exercise.Results:Significant increases were seen in ABPI in the patients treated with PTA at all assessment to 15 months. However in terms of improved walking performance, the most significant changes in claudication and maximum walking distance were seen in the exercise training group. At long term follow-up, there was no significant difference between the groups. Subgroup analysis by angiographic site of disease showed greater functional improvement in those patients with disease confined to the superficial femoral artery treated by exercise training. The overall prognosis for the whole group of patients was benign, with only two (4%) undergoing amputation.Conclusions:Exercise training confers a greater improvement in claudication and maximum walking distance than PTA, especially in patients with disease confined to the superficial femoral artery

    Searching for Lyme borreliosis in Australia: Results of a canine sentinel study

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    Background: Lyme borreliosis is a common tick-borne disease of the northern hemisphere that is caused by bacterial spirochaetes of the Borrelia burgdorferi (sensu lato) (Bbsl) complex. To date, there has been no convincing evidence for locally-acquired Lyme borreliosis on the Australian continent and there is currently a national debate concerning the nature and distributions of zoonotic tick-transmitted infectious disease in Australia. In studies conducted in Europe and the United States, dogs have been used as sentinels for tick-associated illness in people since they readily contact ticks that may harbour zoonotic pathogens. Applying this principle, we used a combination of serological assays to test dogs living in tick 'hot spots' and exposed to the Australian paralysis tick, Ixodes holocyclus, for evidence of exposure to B. burgdorferi (s.l.) antigens and other vector-borne pathogens. Results: Altogether, 555 dogs from four demographic groups were recruited into this study. One dog had evidence of exposure to Anaplasma spp. but no other dog was positive in screening tests. A total of 122 dogs (22.0%) had a kinetic ELISA (KELA) unit value > 100, and one dog with a high titre (399.9 KELA units) had been vaccinated against B. burgdorferi (sensu stricto) before travelling to Australia. Older dogs and those with a history of tick paralysis were significantly more likely to have a KELA unit value > 100. Line immunoassay analysis revealed moderate-to-weak (equivocal) bands in 27 (4.9%) dogs. Conclusions: Except for a single dog presumed to have been exposed to Anaplasma platys, infection with Anaplasma spp. B. burgdorferi (s.l.), Ehrlichia spp., and Dirofilaria immitis, was not detected in the cohort of Australian dogs evaluated in this study. These results provide further evidence that Lyme borreliosis does not exist in Australia but that cross-reacting antibodies (false positive results) are common and may be caused by the transmission of other tick-associated organisms

    Prospective evaluation of quality of life after conventional abdominal aortic aneurysm surgery

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    Objectives:To evaluate the changes in quality of life following conventional abdominal aortic aneurysm repair.Design:Prospective study.Materials and methods:Fifty-nine consecutive patients (50 men; nine women) in two surgical centres were investigated preoperatively, and at 6 weeks, 3 months and 6 months postoperatively. Quality of life was measured using the Short Form 36 (SF 36) questionnaire and the York Quality of Life questionnaire, from which the Rosser index was calculated.Results:Rosser index assessment showed restoration of quality of life to preoperative levels by 3 months, and significant improvement at 6 months. Changes in the SF 36 revealed significant improvement in mental health, and physical role limitation at all times postoperatively. Social function worsened at 6 weeks but improved to preoperative levels by 3 and 6 months after surgery.Conclusions:Quality of life was improved after open aortic aneurysm repair. The time course of recovery shows a predominant improvement between 6 weeks and 3 months postoperatively

    Expression of rabbit IL-4 by recombinant myxoma viruses enhances virulence and overcomes genetic resistance to myxomatosis

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    AbstractRabbit IL-4 was expressed in the virulent standard laboratory strain (SLS) and the attenuated Uriarra (Ur) strain of myxoma virus with the aim of creating a Th2 cytokine environment and inhibiting the development of an antiviral cell-mediated response to myxomatosis in infected rabbits. This allowed testing of a model for genetic resistance to myxomatosis in wild rabbits that have undergone 50 years of natural selection for resistance to myxomatosis. Expression of IL-4 significantly enhanced virulence of both virulent and attenuated virus strains in susceptible (laboratory) and resistant (wild) rabbits. SLS-IL-4 completely overcame genetic resistance in wild rabbits. The pathogenesis of SLS-IL-4 was compared in susceptible and resistant rabbits. The results support a model for resistance to myxomatosis of an enhanced innate immune response controlling virus replication and allowing an effective antiviral cell-mediated immune response to develop in resistant rabbits. Expression of IL-4 did not overcome immunity to myxomatosis induced by immunization

    An Internet-Based Course And The Application Of Employment-Based Methods In Civil Engineering Projects

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    The paper addresses the question of how educational activities in civil engineering in the Netherlands can contribute to the application of employment-based programs in developing countries. National policy makers and international donor representatives acknowledge the various advantages of employment-based programs. However, for a number of reasons the implementation of such programs generally forms a severe bottleneck. Because of the limited number of implemented programs the employment-based methods have not been sufficiently tested and improved, which in turn inhibits reaching the full potential of the employmentbased policies. The University of Twente (UT) has developed a modest program to assist interested governmental and private organisations to enhance the scope and quality of implementation of projects. Based on the existing body of knowledge - to which in particular ILO, WORK and IHE have contributed - a course has been established that can be followed via the Internet. This course offers the basic principles of employment-based civil engineering as well as a framework to develop and implement project proposals. Each of the three modules consists of course material (texts, pictures and films) and an individual assignment that the student submits to the lecturer. Next, the University's internship and traineeship programs provide interested candidates an opportunity to render practical assistance at the spot while at the same time collecting and processing data. After their preparation at the UT the students normally spend 3 to 4 months abroad, frequently in outlying areas. The preparation and execution are carried out under supervision of University staff, while the University also provides financial support by paying for the international travel. Besides their direct contribution to development activities, the students' experiences and reports form the input for improvements in implementation and policy making. So far over 20 students have executed such assignments, mainly in South Africa. The oral presentation of the paper includes a demonstration of the Internet-based course and a discussion with participants on concrete project ideas

    Fluctuating Filaments I: Statistical Mechanics of Helices

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    We examine the effects of thermal fluctuations on thin elastic filaments with non-circular cross-section and arbitrary spontaneous curvature and torsion. Analytical expressions for orientational correlation functions and for the persistence length of helices are derived, and it is found that this length varies non-monotonically with the strength of thermal fluctuations. In the weak fluctuation regime, the local helical structure is preserved and the statistical properties are dominated by long wavelength bending and torsion modes. As the amplitude of fluctuations is increased, the helix ``melts'' and all memory of intrinsic helical structure is lost. Spontaneous twist of the cross--section leads to resonant dependence of the persistence length on the twist rate.Comment: 5 figure

    Electromigration-Induced Flow of Islands and Voids on the Cu(001) Surface

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    Electromigration-induced flow of islands and voids on the Cu(001) surface is studied at the atomic scale. The basic drift mechanisms are identified using a complete set of energy barriers for adatom hopping on the Cu(001) surface, combined with kinetic Monte Carlo simulations. The energy barriers are calculated by the embedded atom method, and parameterized using a simple model. The dependence of the flow on the temperature, the size of the clusters, and the strength of the applied field is obtained. For both islands and voids it is found that edge diffusion is the dominant mass-transport mechanism. The rate limiting steps are identified. For both islands and voids they involve detachment of atoms from corners into the adjacent edge. The energy barriers for these moves are found to be in good agreement with the activation energy for island/void drift obtained from Arrhenius analysis of the simulation results. The relevance of the results to other FCC(001) metal surfaces and their experimental implications are discussed.Comment: 9 pages, 13 ps figure

    Scale-free memory model for multiagent reinforcement learning. Mean field approximation and rock-paper-scissors dynamics

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    A continuous time model for multiagent systems governed by reinforcement learning with scale-free memory is developed. The agents are assumed to act independently of one another in optimizing their choice of possible actions via trial-and-error search. To gain awareness about the action value the agents accumulate in their memory the rewards obtained from taking a specific action at each moment of time. The contribution of the rewards in the past to the agent current perception of action value is described by an integral operator with a power-law kernel. Finally a fractional differential equation governing the system dynamics is obtained. The agents are considered to interact with one another implicitly via the reward of one agent depending on the choice of the other agents. The pairwise interaction model is adopted to describe this effect. As a specific example of systems with non-transitive interactions, a two agent and three agent systems of the rock-paper-scissors type are analyzed in detail, including the stability analysis and numerical simulation. Scale-free memory is demonstrated to cause complex dynamics of the systems at hand. In particular, it is shown that there can be simultaneously two modes of the system instability undergoing subcritical and supercritical bifurcation, with the latter one exhibiting anomalous oscillations with the amplitude and period growing with time. Besides, the instability onset via this supercritical mode may be regarded as "altruism self-organization". For the three agent system the instability dynamics is found to be rather irregular and can be composed of alternate fragments of oscillations different in their properties.Comment: 17 pages, 7 figur

    Reduced specificity of autobiographical memory and depression: The role of executive control

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    It has been widely established that depressed mood states and clinical depression, as well as a range of other psychiatric disorders, are associated with a relative difficulty in accessing specific autobiographical information in response to emotion-related cue words on an Autobiographical Memory Test (AMT; J. M. G. Williams & K. Broadbent, 1986). In 8 studies the authors examined the extent to which this relationship is a function of impaired executive control associated with these mood states and clinical disorders. Studies 1-4 demonstrated that performance on the AMT is associated with performance on measures of executive control, independent of depressed mood. Furthermore, Study 1 showed that executive control (as measured by verbal fluency) mediated the relationship between both depressed mood and a clinical diagnosis of eating disorder and AMT performance. Using a stratified sample in Study 5, the authors confirmed the positive association between depressed mood and impaired performance on the AMT. Studies 6-8 involved experimental manipulations of the parameters of the AMT designed to further indicate that reduced executive control is to a significant extent driving the relationship between depressed mood and AMT performance. The potential role of executive control in accounting for other aspects of the AMT literature is discussed. (PsycINFO Database Record (c) 2007 APA, all rights reserved)
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