3,832 research outputs found

    The social cognition of medical knowledge, with special reference to childhood epilepsy

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    This paper arose out of an engagement in medical communication courses at a Gulf university. It deploys a theoretical framework derived from a (critical) sociocognitive approach to discourse analysis in order to investigate three aspects of medical discourse relating to childhood epilepsy: the cognitive processes that are entailed in relating different types of medical knowledge to their communicative context; the types of medical knowledge that are constituted in the three different text types analysed; and the relationship between these different types of medical knowledge and the discursive features of each text type. The paper argues that there is a cognitive dimension to the human experience of understanding and talking about one specialized from of medical knowledge. It recommends that texts be studied in medical communication courses not just in terms of their discrete formal features but also critically, in terms of the knowledge which they produce, transmit and reproduce

    Interaction of ballistic quasiparticles and vortex configurations in superfluid He3-B

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    The vortex line density of turbulent superfluid He3-B at very low temperature is deduced by detecting the shadow of ballistic quasiparticles which are Andreev reflected by quantized vortices. Until now the measured total shadow has been interpreted as the sum of shadows arising from interactions of a single quasiparticle with a single vortex. By integrating numerically the quasi-classical Hamiltonian equations of motion of ballistic quasiparticles in the presence of nontrivial but relatively simple vortex systems (such as vortex-vortex and vortex-antivortex pairs and small clusters of vortices) we show that partial screening can take place, and the total shadow is not necessarily the sum of the shadows. We have also found that it is possible that, upon impinging on complex vortex configurations, quasiparticles experience multiple reflections, which can be classical, Andreev, or both.Comment: To appear in Phys Rev

    Nanoantenna-enhanced ultrafast nonlinear spectroscopy of a single gold nanoparticle

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    Optical nanoantennas are a novel tool to investigate previously unattainable dimensions in the nanocosmos. Just like their radio-frequency equivalents, nanoantennas enhance the light-matter interaction in their feed gap. Antenna enhancement of small signals promises to open a new regime in linear and nonlinear spectroscopy on the nanoscale. Without antennas especially the nonlinear spectroscopy of single nanoobjects is very demanding. Here, we present for the first time antenna-enhanced ultrafast nonlinear optical spectroscopy. In particular, we utilize the antenna to determine the nonlinear transient absorption signal of a single gold nanoparticle caused by mechanical breathing oscillations. We increase the signal amplitude by an order of magnitude which is in good agreement with our analytical and numerical models. Our method will find applications in linear and nonlinear spectroscopy of nanoobjects, ranging from single protein binding events via nonlinear tensor elements to the limits of continuum mechanics

    Biogeomorphology in the field: bedforms and species, a mystic relationship

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    Fine-scale seabed mapping (Owenia fusiformis, and the razor clam Ensis directus) occur near bedload convergence zones resulting from a mutually evasive flood- and ebb-dominant channel system. Such zones are at the end of the channels, hence also fine grained sediments, food and larvae are trapped. The combination of the coarser-grained bedload with thedeposition of fines is indeed the optimum for a lot of suspension and detritus feeders. Still, highest abundances occur at the fringes of such a system where stress levels are intermediate. Hypotheses were successfully tested along the Dutch coastal zone. Those insights are important to assess changes in seafloor integrity and hydrographic conditions

    Decay process accelerated by tunneling in its very early stage

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    We examine a fast decay process that arises in the transition period between the Gaussian and exponential decay processes in quantum decay systems. It is usually expected that the decay is decelerated by a confinement potential barrier. However, we find a case where the decay in the transition period is accelerated by tunneling through a confinement potential barrier. We show that the acceleration gives rise to an appreciable effect on the time evolution of the nonescape probability of the decay system.Comment: 4 pages, 6 figures; accepted for publication in Phys. Rev.

    Effects of comorbidity on Tourette's tic severity and quality of life

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    Objective The aim of this study is to gain more insight in the differential contributions of anxiety, depression and obsessive-compulsive (OC) symptom severity to quality of life (QoL) and tic severity in adults with Tourette Disorder (TD). Methods Self-reported OC symptom, anxiety and depression severity measures were used to investigate their predictive value on QoL and Tic severity in adult TD patients (N = 187), using correlation, regression, and mediation analyses. Results Tic severity has no effect on QoL. Depression severity directly reduces QoL, whereas anxiety and OC symptom severity have an indirect effect on QoL, mediated by depression severity. OC symptom severity directly affects tic severity, whereas depression and anxiety severity do not have a direct effect on tic or OC severity. Finally, anxiety severity indirectly impacts tic severity, with OC symptom severity functioning as a mediator. Conclusion In line with and extending previous studies, these findings indicate that OC symptom severity directly influences tic symptom severity whereas depression severity directly influences QoL in TD. Results imply that to improve QoL in TD patients, treatment should primarily focus on diminishing OC and depressive symptom severity rather than focusing on tic reduction
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