5,220 research outputs found

    Augmentative and Alternative Communication in the Intensive Care Unit: A Service Delivery Model

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    Patients in the intensive care unit (ICU) often find it difficult or impossible to verbally communicate due to mechanical ventilation, tracheostomy tubes or increased fatigue and delirium. Augmentative and alternative communication (AAC) can provide ICU patients with a way to communicate during their ICU admittance. However, few hospitals currently have a systematic service delivery model in place for providing AAC tools and supports to ICU patients. This resource manual provides an outline for creating and implementing an AAC service delivery model along with AAC materials and resources appropriate for an ICU. Explanations of how each material is used, who they are appropriate for and how they can modify are provided for each AAC method discussed. Providing a detailed and systematic AAC service delivery model, such as the one outlined in this resource manual, allows ICU patients to effectively and efficiently communicate during a frightening and anxiety-provoking time

    Must Do @ VCU

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    Must Do @ VCU is a set of annual collegial activities that can be performed throughout the year, by faculty, staff and students. These VCU-centered activities are considered to be the things that give VCU its identity. The goal of Must Do @ VCU is to generate a sense of community and of belonging to the University. VCU is a relatively new University and its traditions are therefore not well-established. Must Do @ VCU aims to build on shared experiences as a method to establish VCU culture

    Additivity properties of a Gaussian Channel

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    The Amosov-Holevo-Werner conjecture implies the additivity of the minimum Re'nyi entropies at the output of a channel. The conjecture is proven true for all Re'nyi entropies of integer order greater than two in a class of Gaussian bosonic channel where the input signal is randomly displaced or where it is coupled linearly to an external environment.Comment: 9 pages, 1 figure (minor error present in the published version corrected

    Minimum Renyi and Wehrl entropies at the output of bosonic channels

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    The minimum Renyi and Wehrl output entropies are found for bosonic channels in which the signal photons are either randomly displaced by a Gaussian distribution (classical-noise channel), or in which they are coupled to a thermal environment through lossy propagation (thermal-noise channel). It is shown that the Renyi output entropies of integer orders z>1 and the output Wehrl entropy are minimized when the channel input is a coherent state.Comment: Minimal revision. Accepted for publication on Phys. Rev.

    Landau polaritons in highly non-parabolic 2D gases in the ultra-strong coupling regime

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    We probe ultra-strong light matter coupling between metallic terahertz metasurfaces and Landau-level transitions in high mobility 2D electron and hole gases. We utilize heavy-hole cyclotron resonances in strained Ge and electron cyclotron resonances in InSb quantum wells, both within highly non-parabolic bands, and compare our results to well known parabolic AlGaAs/GaAs quantum well (QW) systems. Tuning the coupling strength of the system by two methods, lithographically and by optical pumping, we observe a novel behavior clearly deviating from the standard Hopfield model previously verified in cavity quantum electrodynamics: an opening of a lower polaritonic gap

    Information-theoretic approach to the study of control systems

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    We propose an information-theoretic framework for analyzing control systems based on the close relationship of controllers to communication channels. A communication channel takes an input state and transforms it into an output state. A controller, similarly, takes the initial state of a system to be controlled and transforms it into a target state. In this sense, a controller can be thought of as an actuation channel that acts on inputs to produce desired outputs. In this transformation process, two different control strategies can be adopted: (i) the controller applies an actuation dynamics that is independent of the state of the system to be controlled (open-loop control); or (ii) the controller enacts an actuation dynamics that is based on some information about the state of the controlled system (closed-loop control). Using this communication channel model of control, we provide necessary and sufficient conditions for a system to be perfectly controllable and perfectly observable in terms of information and entropy. In addition, we derive a quantitative trade-off between the amount of information gathered by a closed-loop controller and its relative performance advantage over an open-loop controller in stabilizing a system. This work supplements earlier results [H. Touchette, S. Lloyd, Phys. Rev. Lett. 84, 1156 (2000)] by providing new derivations of the advantage afforded by closed-loop control and by proposing an information-based optimality criterion for control systems. New applications of this approach pertaining to proportional controllers, and the control of chaotic maps are also presented.Comment: 18 pages, 7 eps figure

    High-Latitude Tree Growth and Satellite Vegetation Indices: Correlations and Trends in Russia and Canada (1982-2008)

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    Vegetation in northern high latitudes affects regional and global climate through energy partitioning and carbon storage. Spaceborne observations of vegetation, largely based on the normalized difference vegetation index (NDVI), suggest decreased productivity during recent decades in many regions of the Eurasian and North American boreal forests. To improve interpretation of NDVI trends over forest regions, we examined the relationship between NDVI from the advanced very high resolution radiometers and tree ring width measurements, a proxy of tree productivity. We collected tree core samples from spruce, pine, and larch at 22 sites in northeast Russia and northwest Canada. Annual growth rings were measured and used to generate site-level ring width index (RWI) chronologies. Correlation analysis was used to assess the association between RWI and summer NDVI from 1982 to 2008, while linear regression was used to examine trends in both measurements. The correlation between NDVI and RWI was highly variable across sites, though consistently positive (r = 0.43, SD = 0.19, n = 27). We observed significant temporal autocorrelation in both NDVI and RWI measurements at sites with evergreen conifers (spruce and pine), though weak autocorrelation at sites with deciduous conifers (larch). No sites exhibited a positive trend in both NDVI and RWI, although five sites showed negative trends in both measurements. While there are technological and physiological limitations to this approach, these findings demonstrate a positive association between NDVI and tree ring measurements, as well as the importance of considering lagged effects when modeling vegetation productivity using satellite data

    Vertical stiffness asymmetries during drop jumping are related to ankle stiffness asymmetries

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    Asymmetry in vertical stiffness has been associated with increased injury incidence and impaired performance. The determinants of vertical stiffness asymmetry have not been previously investigated. Eighteen healthy males performed three unilateral drop jumps during which vertical stiffness and joint stiffness of the ankle and knee were calculated. Reactive strength index was also determined during the jumps using the ratio of flight time to ground contact time. ‘Moderate’ differences in vertical stiffness (t17 = 5.49; P < 0.001), ‘small’ differences in centre of mass displacement (t17 = -2.19; P = 0.043) and ‘trivial’ differences in ankle stiffness (t17 = 2.68; P = 0.016) were observed between stiff and compliant limbs. A model including ankle stiffness and reactive strength index symmetry angles explained 79% of the variance in vertical stiffness asymmetry (R2 = 0.79; P < 0.001). None of the symmetry angles were correlated to jump height or reactive strength index. Results suggest that asymmetries in ankle stiffness may play an important role in modulating vertical stiffness asymmetry in recreationally trained males

    Real-world word learning: exploring children's developing semantic representations of a science term

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    Assessments of lexical acquisition are often limited to pre-school children on forced choice comprehension measures. This study assessed the understandings 30 school-age children (mean age = 6;7) acquired about the science term, eclipse following a naturalistic exposure to a solar eclipse. The knowledge children acquired about eclipses and a control term, comet was assessed at three points in time (baseline-test, two-week post-test and five-month post-test) using a range of assessment tasks (multiple-choice comprehension, picture-naming, drawing and a model of a solar system task). Children's knowledge was compared to 15 adult controls during the baseline-test and two-week post-test. Children acquired extensive knowledge about eclipses, but not comets; at the two-week post-test and five-month post-test, the majority of children named and drew eclipses and „made? an eclipse using models of the sun, moon and earth. Also, children's eclipse knowledge more closely approximated adult-level understandings at the two-week post-test than at the baseline-test. Implications for the study of lexical acquisition in later development are discussed
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