114 research outputs found

    Increase in Peripheral Arterial Tone Predicts Myocardial Ischemia Induced by Mental Stress

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    Mental stress ischemia (MSI) is associated with poor prognosis for coronary artery disease (CAD) and is amenable to treatment, yet no easily administered test exists to diagnose it. Given the known increase in systemic vascular tone in response to stress, we studied the ability of peripheral arterial tonometry (PAT), a noninvasive functional measure of arterial tone, to predict those vulnerable to MSI. Seventy-seven patients with chronic stable CAD were subjected to mental stress with concomitant assessment of myocardial perfusion and pulse wave amplitude. Nuclear perfusion imaging was used to document MSI, and PAT was used to measure pulse wave and microarterial tone. A ratio of PAT measurements during stress to those before stress was used to characterize vascular responses. Serum catecholamines and endothelin-1 (ET-1) were simultaneously measured. Subjects who experienced MSI had a lower average PAT ratio than those who did not (0.76 ± 0.04 vs. 0.91 ± 0.05, P = 0.03). A receiver operating characteristics curve for PAT ratio predicting MSI had an area under the curve of 0.613 (standard error, 0.065, one-sided P = 0.04). Maxima of sensitivity and specificity were observed at a threshold of 0.78 to define an abnormal PAT ratio. Cross-tabulation of groups above and below this threshold with groups of subjects with and without MSI showed a significant predictive relationship between PAT ratio and MSI (P = 0.03). Subjects at or below this threshold (≤0.78) displayed a significant increase in norepinephrine levels during mental stress (235 pg/ml at baseline, 259 pg/ml during mental stress, P = 0.007). Subjects above this threshold (\u3e0.78) displayed a significant decline in their ET-1 levels 24 hours after mental stress (1.15 pg/ml after mental stress, 0.93 pg/ml 24 hours later, P = 0.01), while those at or below threshold had a continued increase. PAT ratio is a complex functional measure of peripheral arterial tone that significantly predicts the occurrence of MSI. It may have clinical value as an easily administered screening test for MSI

    L.N. Tolstoy's "The Kreutzer sonata" as a work on the body politic

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    This thesis examines L. N. Tolstoy's representation of sexuality in late­ nineteenth-century Russia through his novella, The Kreutzer Sonata (1889).* I draw on recent theoretical works of Michel Foucault and Alphonso Lingis to investigate the political and economic factors significant to the development of sexuality in capitalist cultures such as nineteenth-century Russia. I show that Tolstoy's depiction of the political empowerment and economic motivation behind sexuality are the most significant factors in shaping human sexuality, which concurs with the recent theoretical models. I then show how women are subordinated to comply with male sexuality to achieve its political and economic ends. From this emerges a masculine view of women as subservient lower animals. I incorporate an historical account of human relationships with animals and how women became included in that lower order by men, which is vividly portrayed in The Kreutzer Sonata and supported by feminist theory. After building a representative picture of sexuality and relations between the sexes, I demonstrate how Tolstoy articulates the protagonist in his novella to create a polemics against the foundations of that society. Tolstoy rehabilitates the status of a woman in favour of equality between the sexes, thus subverting all modes of life based on perceived masculine superiority. This thesis will conclude, therefore, that Tolstoy's The Kreutzer Sonata is an indictment and condemnation of capitalist social organisation based on the exploitation of populations through their sexuality in Russia as in the West

    Reliability of mechanical sprint profiles in state U16 female basketball athletes

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    BLUF: Mechanical sprint characteristics produce acceptable trial to trial reliability in state U16 female basketball athletes. INTRODUCTION: Sprint acceleration is a key component of basketball performance that occurs frequently during competition that is commonly measured over various distances using timing gates. Sprint profiling is a topical area of research that provides practitioners an insight into the underlying mechanical characteristics that contributed to the performance. These include theoretical maximal force, theoretical maximal velocity, maximum power, slope of the force velocity relationship, maximum ratio of force, decrease in ratio of force and max speed. This study aimed to investigate the reliability of mechanical sprint characteristics in state U16 female basketball athletes

    A Molecular Einstein Ring at z=4.12: Imaging the Dynamics of a Quasar Host Galaxy Through a Cosmic Lens

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    We present high-resolution (0.3") Very Large Array (VLA) imaging of the molecular gas in the host galaxy of the high redshift quasar PSS J2322+1944 (z=4.12). These observations confirm that the molecular gas (CO) in the host galaxy of this quasar is lensed into a full Einstein ring, and reveal the internal dynamics of the molecular gas in this system. The ring has a diameter of ~1.5", and thus is sampled over ~20 resolution elements by our observations. Through a model-based lens inversion, we recover the velocity gradient of the molecular reservoir in the quasar host galaxy of PSS J2322+1944. The Einstein ring lens configuration enables us to zoom in on the emission and to resolve scales down to ~1 kpc. From the model-reconstructed source, we find that the molecular gas is distributed on a scale of 5 kpc, and has a total mass of M(H2)=1.7 x 10^10 M_sun. A basic estimate of the dynamical mass gives M_dyn = 4.4 x 10^10 (sin i)^-2 M_sun, that is, only ~2.5 times the molecular gas mass, and ~30 times the black hole mass (assuming that the dynamical structure is highly inclined). The lens configuration also allows us to tie the optical emission to the molecular gas emission, which suggests that the active galactic nucleus (AGN) does reside within, but not close to the center of the molecular reservoir. Together with the (at least partially) disturbed structure of the CO, this suggests that the system is interacting. Such an interaction, possibly caused by a major `wet' merger, may be responsible for both feeding the quasar and fueling the massive starburst of 680 M_sun/yr in this system, in agreement with recently suggested scenarios of quasar activity and galaxy assembly in the early universe.Comment: 9 pages, 7 figures, to appear in ApJ (accepted June 27, 2008

    When Darwin Met Einstein: Gravitational Lens Inversion with Genetic Algorithms

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    Gravitational lensing can magnify a distant source, revealing structural detail which is normally unresolvable. Recovering this detail through an inversion of the influence of gravitational lensing, however, requires optimisation of not only lens parameters, but also of the surface brightness distribution of the source. This paper outlines a new approach to this inversion, utilising genetic algorithms to reconstruct the source profile. In this initial study, the effects of image degradation due to instrumental and atmospheric effects are neglected and it is assumed that the lens model is accurately known, but the genetic algorithm approach can be incorporated into more general optimisation techniques, allowing the optimisation of both the parameters for a lensing model and the surface brightness of the source.Comment: 9 pages, to appear in PAS

    Melatonin for rapid eye movement sleep behavior disorder in Parkinson's disease : a randomised controlled trial

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    Background Melatonin may reduce REM-sleep behavior disorder (RBD) symptoms in Parkinson's disease (PD), though robust clinical trials are lacking. Objective To assess the efficacy of prolonged-release (PR) melatonin for RBD in PD. Methods Randomized, double-blind, placebo-controlled, parallel-group trial with an 8-week intervention and 4-week observation pre- and postintervention (ACTRN12613000648729). Thirty PD patients with rapid eye movement sleep behavior disorder were randomized to 4 mg of prolonged-release melatonin (Circadin) or matched placebo, ingested orally once-daily before bedtime. Primary outcome was the aggregate of rapid eye movement sleep behavior disorder incidents averaged over weeks 5 to 8 of treatment captured by a weekly diary. Data were included in a mixed-model analysis of variance (n = 15 per group). Results No differences between groups at the primary endpoint (3.4 events/week melatonin vs. 3.6 placebo; difference, 0.2; 95% confidence interval = -3.2 to 3.6; P = 0.92). Adverse events included mild headaches, fatigue, and morning sleepiness (n = 4 melatonin; n = 5 placebo). Conclusion Prolonged-release melatonin 4 mg did not reduce rapid eye movement sleep behavior disorder in PD. (c) 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society

    Haemophagocytic lymphohistiocytosis: A fulminant syndrome associated with multiorgan failure and high mortality that frequently masquerades as sepsis and shock

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    Acquired haemophagocytic lymphohistiocytosis (HLH) is a condition involving cytokine overproduction by defective cytotoxic T lymphocytes and natural killer cells, resulting in life-threatening cytopenias and multiorgan infiltration and dysfunction. Triggers for acquired HLH vary and include viruses, malignancies and autoimmune conditions. Recent reports suggest that HLH may be underdiagnosed owing to variable clinical presentations, diagnostic criteria and a low level of awareness on the part of medical personnel, thus delaying prompt treatment and contributing to high mortality rates. Five patients in whom acquired HLH was diagnosed, following bone marrow investigations, for the period of May - September 2013 are presented. All were at an advanced stage of their disease at time of diagnosis. The three patients who were HIV-positive had a coexisting malignancy at the time of HLH diagnosis, which may have triggered HLH. A definite trigger was not identified in the remaining two HIV-negative patients despite early concerns regarding autoimmune disease. Two patients received timeous diagnosis, started chemotherapy and are currently improving. The remaining three succumbed to their illness. Adult acquired HLH may be more common in the acute care setting than currently appreciated. As awareness of this condition and its treatment is currently low, it may remain undiagnosed until the disease has evolved into multiorgan failure. Fever in the absence of infectious agents, marked hyperferritinaemia, unexplained cytopenias, organomegaly or liver dysfunction should raise the suspicion of HLH. Timeous introduction of therapy will improve outcomes

    Modelling of the Complex CASSOWARY/SLUGS Gravitational Lenses

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    We present the first high-resolution images of CSWA 31, a gravitational lens system observed as part of the SLUGS (Sloan Lenses Unravelled by Gemini Studies) program. These systems exhibit complex image structure with the potential to strongly constrain the mass distribution of the massive lens galaxies, as well as the complex morphology of the sources. In this paper, we describe the strategy used to reconstruct the unlensed source profile and the lens galaxy mass profiles. We introduce a prior distribution over multi-wavelength sources that is realistic as a representation of our knowledge about the surface brightness profiles of galaxies and groups of galaxies. To carry out the inference computationally, we use Diffusive Nested Sampling, an efficient variant of Nested Sampling that uses Markov Chain Monte Carlo (MCMC) to sample the complex posterior distributions and compute the normalising constant. We demonstrate the efficacy of this approach with the reconstruction of the group-group gravitational lens system CSWA 31, finding the source to be composed of five merging spiral galaxies magnified by a factor of 13.Comment: Accepted for publication in MNRA

    An updated re-entry analysis of the Hubble Space Telescope

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    The Hubble Space Telescope (HST), launched in 1990, has without question given us a better understanding of the Universe [1]. The storied spacecraft has far exceeded its design life and, in spite of four repair missions, is nearing the end of its useful lifespan. Originally designed to be returned by the Space Shuttle, the HST has no on-board propulsion system. A 2012 study estimated that without intervention, the HST will re-enter the atmosphere in approximately 2027 with a 1:240 risk of fatality [2]. This study updates that analysis with more recent de-orbit technologies and updated trajectory information. We propose a design solution to safely perform a targeted de-orbit, assuming a worst-case scenario (a non-functional, tumbling spacecraft). Multiple de-orbit options are assessed to actively capture the satellite. Results frame an approach that could be accomplished with proven technologies at reasonable cost to improve the fatality risk as required by US Government regulation [3]. Moreover, delayed action would significantly increase mission cost and complexity so we recommend a project start in the near future
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