70 research outputs found

    Total ventricular assist for long-term treatment of heart failure

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    The cadaver of a Caucasian man with a supernumerary fourth dorsal interosseous muscle in the right hand: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The human hand is a complex anatomic entity consisting of many muscles, nerves, and vessels, thus providing a special ability to perform accurate and meticulous movements. In this group of muscles are the four dorsal interosseous muscles.</p> <p>Case presentation</p> <p>A distinct supernumerary fourth dorsal interosseous muscle was found in the right hand of the cadaver of a 76-year-old Caucasian man without any other concomitant abnormality.</p> <p>Conclusions</p> <p>The presence of such an additional muscle in the hand should be considered in the management of hand deformities, whether the treatment is conservative or surgical.</p

    Floppy mitral valve/mitral valve prolapse syndrome: Beta-adrenergic receptor polymorphism may contribute to the pathogenesis of symptoms

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    AbstractBackgroundCertain patients with floppy mitral valve (FMV)/mitral valve prolapse (MVP) may have symptoms that cannot be explained on the severity of mitral valvular regurgitation (MVR) alone; hypersensitivity to adrenergic stimulation has been suggested in this group defined as the FMV/MVP syndrome.MethodsNinety-eight patients (75 men, 23 women) with mitral valve surgery for FMV/MVP were studied. Of those 41 (42%) had symptoms consistent with FMV/MVP syndrome [29 men (39%), 12 women (52%)]; median age of symptom onset was 30 years (range 10–63 years) and median duration of symptoms prior to valve surgery was 16 years (range 3–50 years). Ninety-nine individuals (70 men, 29 women) without clinical evidence of any disease were used as controls. Genotyping of β1 and β2 adrenergic receptors was performed.Resultsβ-Adrenergic receptor genotypes (β1 and β2) were similar between control and overall FMV/MVP patients. Subgroup analysis of patients, however, demonstrated that the genotype C/C at position 1165 resulting in 389 Arg/Arg of the β1 receptor was more frequent in women compared to those without FMV/MVP syndrome and to normal control women (p<0.025). This polymorphism may be related to hypersensitivity to adrenergic stimulation as reported previously in these patients.ConclusionThis study shows a large proportion of patients with FMV/MVP, predominantly women, had symptoms consistent with the FMV/MVP syndrome for many years prior to the development of significant MVR, and thus symptoms cannot be attributed to the severity of MVR alone. Further, women with FMV/MVP syndrome, symptoms at least partially may be related to β1-adrenergic receptor polymorphism, which has been shown previously to be associated with a hyperresponse to adrenergic stimulation

    Detailed optical and near-infrared polarimetry, spectroscopy and broadband photometry of the afterglow of GRB 091018: Polarisation evolution

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    [Abridged] A number of phenomena have been observed in GRB afterglows that defy explanation by simple versions of the standard fireball model, leading to a variety of new models. Polarimetry can be a major independent diagnostic of afterglow physics, probing the magnetic field properties and internal structure of the GRB jets. In this paper we present the first high quality multi-night polarimetric light curve of a Swift GRB afterglow, aimed at providing a well calibrated dataset of a typical afterglow to serve as a benchmark system for modelling afterglow polarisation behaviour. In particular, our dataset of the afterglow of GRB 091018 (at redshift z=0.971) comprises optical linear polarimetry (R band, 0.13 - 2.3 days after burst); circular polarimetry (R band) and near-infrared linear polarimetry (Ks band). We add to that high quality optical and near-infrared broadband light curves and spectral energy distributions as well as afterglow spectroscopy. The linear polarisation varies between 0 and 3%, with both long and short time scale variability visible. We find an achromatic break in the afterglow light curve, which corresponds to features in the polarimetric curve. We find that the data can be reproduced by jet break models only if an additional polarised component of unknown nature is present in the polarimetric curve. We probe the ordered magnetic field component in the afterglow through our deep circular polarimetry, finding P_circ < 0.15% (2 sigma), the deepest limit yet for a GRB afterglow, suggesting ordered fields are weak, if at all present. Our simultaneous R and Ks band polarimetry shows that dust induced polarisation in the host galaxy is likely negligible.Comment: 20 pages, 14 figures, 3 tables. Accepted for publication in MNRAS. Some figures are reduced in quality to comply with arXiv size requirement

    Multiscale simulation of polymer melt viscoelasticity: Expanded-ensemble Monte Carlo coupled with atomistic nonequilibrium molecular dynamics

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    We present a powerful framework for computing the viscoelastic properties of polymer melts based on an efficient coupling of two different atomistic models: the first is represented by the nonequilibrium molecular dynamics method and is considered as the microscale model. The second is represented by a Monte Carlo (MC) method in an expanded statistical ensemble and is free from any long time scale constraints. Guided by recent developments in nonequilibrium thermodynamics, the expanded ensemble incorporates appropriately defined "field" variables driving the corresponding structural variables to beyond equilibrium steady states. The expanded MC is considered as the macroscale solver for the family of all viscoelastic models built on the given structural variable(s). The explicit form of the macroscopic model is not needed; only its structure in the context of the general equation for the nonequilibrium reversible irreversible coupling or generalized bracket formalisms of nonequilibrium thermodynamics is required. We illustrate the method here for the case of unentangled linear polymer melts, for which the appropriate structural variable to consider is the conformation tensor c???. The corresponding Lagrange multiplier is a tensorial field ??. We have been able to compute model-independent values of the tensor ??, which for a wide range of strain rates (covering both the linear and the nonlinear viscoelastic regimes) bring results for the overall polymer conformation from the two models (microscale and macroscale) on top of each other. In a second step, by comparing the computed values of ?? with those suggested by the macroscopic model addressed by the chosen structural variable(s), we can identify shortcomings in the building blocks of the model. How to modify the macroscopic model in order to be consistent with the results of the coupled micro-macro simulations is also discussed. From a theoretical point of view, the present multiscale modeling approach provides a solid framework for the design of improved, more accurate macroscopic models for polymer melts.open151

    The unusual afterglow of the Gamma-Ray Burst 100621A

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    Aims. With the afterglow of GRB 100621A being the brightest detected so far in X-rays, and superb GROND coverage in the optical/NIR during the first few hours, an observational verification of basic fireball predictions seemed possible. Methods. In order to constrain the broad-band spectral energy distribution of the afterglow of GRB 100621A, dedicated observations were performed in the optical/near-infrared with the 7-channel “Gamma-Ray Burst Optical and Near-infrared Detector” (GROND) at the 2.2m MPG/ESO telescope, in the sub-millimeter band with the large bolometer array LABOCA at APEX, and at radio frequencies with ATCA. Utilizing also Swift X-ray observations, we attempt an interpretation of the observational data within the fireball scenario. Results. The afterglow of GRB 100621A shows a very complex temporal as well as spectral evolution. We identify three different emission components, the most spectacular one causing a sudden intensity jump about one hour after the prompt emission. The spectrum of this component is much steeper than the canonical afterglow. We interpret this component using the prescription of Vlasis et al. (2011) for a two-shell collision after the first shell has been decelerated by the circumburst medium. We use the fireball scenario to derive constraints on the microphysical parameters of the first shell. Long-term energy injection into a narrow jet seems to provide an adequate description. Another noteworthy result is the large (AV = 3.6 mag) line-of-sight host extinction of the afterglow in an otherwise extremely blue host galaxy. Conclusions. Some GRB afterglows have shown complex features, and that of GRB 100621A is another good example. Yet, detailed observational campaigns of the brightest afterglows promise to deepen our understanding of the formation of afterglows and the subsequent interaction with the circumburst mediu

    (Re) defining salesperson motivation: current status, main challenges, and research directions

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    The construct of motivation is one of the central themes in selling and sales management research. Yet, to-date no review article exists that surveys the construct (both from an extrinsic and intrinsic motivation context), critically evaluates its current status, examines various key challenges apparent from the extant research, and suggests new research opportunities based on a thorough review of past work. The authors explore how motivation is defined, major theories underpinning motivation, how motivation has historically been measured, and key methodologies used over time. In addition, attention is given to principal drivers and outcomes of salesperson motivation. A summarizing appendix of key articles in salesperson motivation is provided

    PATHS OF FRICTION: \u3ci\u3eKVÆÐAMANNAFÉLAGIÐ\u3c/i\u3e, GEOGRAPHY AND IDENTITY IN 21ST-CENTURY ICELAND

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    Originating in the 14th century, rímur continues to remain a significant tradition in Iceland. Rímur melodies, together with the texts of Icelandic Edda and Saga poetry, were the main form of household entertainment in Iceland for almost six centuries until modern, global technologies cultivated new interests. In the early 20th century, rímur enthusiasts gathered together to form the Iðunn Society of Intoners and Versifiers in Reykjavík, to preserve the singing traditions of their ancestors. Since then, numerous other societies have organized, many within the past decade. In this way, intoning societies have become a medium through which a national Icelandic identity is formed. At the same time, Iceland has witnessed a boom of tourism. I argue this contemporary practice of rímur reflects a nationalistic sensibility within intoning societies, in reaction to tourism and other globalized influences. Drawing from Tim Ingold’s (2011) concern for sound as lived experience and Anna Tsing’s (2005) analysis of friction in globalized space, I examine how intoning societies sonically represent the lived Icelandic experiences among these communities in the face of increased tourism, conflicts, and frictions between local and global perceptions of Icelandic identity. Additionally, I draw upon the work of ecomusicologists Aaron Allen and Kevin Dawe to consider the sonic impact of ecotourism in Iceland. For this study, I have conducted ethnographic research of these societies in Iceland. The rise of ecotourism in Iceland corresponds to the increased calls for preservation of rímur melodies, intoning practices, and traditional Icelandic music, as marks of local Icelandic identity
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