195 research outputs found

    Scientific Visualization to Study Flux Transfer Events at the Community Coordinated Modeling Center

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    In this paper we present results of modeling of reconnection at the dayside magnetopause with subsequent development of flux transfer event signatures. The tools used include new methods that have been added to the suite of visualization methods that are used at the Community Coordinated Modeling Center (CCMC). Flux transfer events result from localized reconnection that connect magnetosheath magnetic field and plasma with magnetospheric fields and plasma and results in flux rope structures that span the dayside magnetopause. The onset of flux rope formation and the three-dimensional structure of flux ropes are studied as they have been modeled by high-resolution magnetohydrodynamic simulations of the dayside magnetosphere of the Earth. We show that flux transfer events are complex three-dimensional structures that require modern visualization and analysis techniques. Two suites of visualization methods are presented and we demonstrate the usefulness of those methods through the CCMC web site to the general science user

    Magnetosonic ULF waves with anomalous plasma - magnetic field correlations: standing waves and inhomogeneous plasmas

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    Ultra-low frequency (ULF) wave observations across the heliosphere often rely on the sign of correlations between plasma (density/pressure) and magnetic field perturbations to distinguish between fast and slow magnetosonic modes. However, the assumptions behind this magnetohydrodynamic result are not always valid, particularly within the magnetosphere which is inhomogeneous and supports standing waves along the geomagnetic field. Through theory and a global simulation, we find both effects can result in anomalous plasma–magnetic field correlations. The interference pattern in standing waves can lead both body and surface magnetosonic waves to have different cross-phases than their constituent propagating waves. Furthermore, if the scale of gradients in the background are shorter than the wavelength or the waves are near-incompressible, then advection by the wave of inhomogeneities can overcome the wave's inherent sense of compression. These effects need to be allowed for and taken into account when applying the typical diagnostic to observations

    The Effects of Pause Length and Location on Auditory Processing in Elderly Adults

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    This study examined the impact of pause length and the location of the pause within a phrase on the processing of an ambiguous phrase in both the elderly and young adults. Both groups displayed similar response patterns in terms of pause location. However, a significant three-way interaction was found for pause length. The pause length needed for accurate processing by the elderly group was significantly longer overall and was differentially influenced by the location within the phrase

    The Effects of Pause Length and Location on Auditory Processing in Elderly Adults

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    This study examined the impact of pause length and the location of the pause within a phrase on the processing of an ambiguous phrase in both the elderly and young adults. Both groups displayed similar response patterns in terms of pause location. However, a significant three-way interaction was found for pause length. The pause length needed for accurate processing by the elderly group was significantly longer overall and was differentially influenced by the location within the phrase

    Self-Contained In-The-Ear Devise to Deliver AAF

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    The design and operating characteristics of the first self-contained in-the-ear device to deliver altered auditory feedback is described for applications with those who stutter. The device incorporates a microdigital signal processor core that reproduces the high fidelity of unaided listening and auditory self-monitoring while at the same time delivering altered auditory feedback. Delayed auditory feedback and frequency-altered feedback signals in combination or isolation can be generated to the user in a cosmetically appealing custom in-the-canal and completely in-the-canal design. Programming of the device is achieved through a personal computer, interface, and fitting software. Researchers and clinicians interested in evaluating persons who stutter outside laboratory settings in a natural environment and persons who stutter looking for an alternative or adjunct to traditional therapy options are ideal candidates for this technology. In both instances an inconspicuous ear level alternative to traditional body worn devices with external microphones and earphones is offered

    Aspiration before and after Supraglottoplasty regardless of Technique

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    Objective. To determine the incidence of preoperative and postoperative aspiration in infants who undergo supraglottoplasty. To determine the effect of cold steel and CO2 laser supraglottoplasty on aspiration in infants with severe laryngomalacia. Design. Retrospective study. Setting. Tertiary pediatric hospital. Patients. Thirty-nine patients who underwent CO2 laser-assisted supraglottoplasty (CLS) or cold steel supraglottoplasty (CSS) for severe laryngomalacia. Main Outcome Measures. Aspiration and upper-airway obstruction. Results. Thirty-nine patients met inclusion criteria (18 males, 21 females). Eighteen patients underwent CSS and 21 patients underwent CLS. 10/39 (25.6%) of the patients had preoperative aspiration, and 2/10 (20%) resolved after supraglottoplasty. New onset aspiration was found in 4/13 (30.8%) in the CSS group and 9/16 (56.3%) in the CLS group. Conclusions. There is no significant difference in the rate of postoperative new-onset aspiration or relief of upper-airway obstruction in the CLS or CSS, is temporary and can be managed with thickened diet or temporary tube feedings. The rate of persistent postoperative aspiration was statistically similar regardless of the method of surgery

    Hemispheric object naming and interhemispheric transfer functions in reading disordered subjects

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    This study measured unilateral, tachistoscopic naming reaction times of normal and reading disordered children to objects representing two levels of picture vocabulary age. Results of an ANCOVA procedure on the latency data showed main effects for group and stimuli, but not visual field. The latency results suggested parallel, central picture naming operations for each group, with the reading disordered children evidencing significantly longer naming reaction times to each level of stimuli. Arc Sine transformed error data were submitted to an analysis of co-variance procedure and showed a significant stimuli x group interaction. Post hoc tests showed accelerated error rates following right hemispheric stimulation, suggesting anomalous interhemispheric transfer of visual images in the present group of reading disordered children. In addition, left hemispheric stimulations produced significantly more naming errors for the reading disordered subjects as compared to the normal children. Such findings may suggest that a group of higher-ordered processing operations may accompany reading disorders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43573/1/11145_2004_Article_BF00555367.pd
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