771 research outputs found

    Effects of bracing in adolescents with idiopathic scoliosis

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    BACKGROUND: The role of bracing in patients with adolescent idiopathic scoliosis who are at risk for curve progression and eventual surgery is controversial. METHODS: We conducted a multicenter study that included patients with typical indications for bracing due to their age, skeletal immaturity, and degree of scoliosis. Both a randomized cohort and a preference cohort were enrolled. Of 242 patients included in the analysis, 116 were randomly assigned to bracing or observation, and 126 chose between bracing and observation. Patients in the bracing group were instructed to wear the brace at least 18 hours per day. The primary outcomes were curve progression to 50 degrees or more (treatment failure) and skeletal maturity without this degree of curve progression (treatment success). RESULTS: The trial was stopped early owing to the efficacy of bracing. In an analysis that included both the randomized and preference cohorts, the rate of treatment success was 72% after bracing, as compared with 48% after observation (propensity-score–adjusted odds ratio for treatment success, 1.93; 95% confidence interval [CI], 1.08 to 3.46). In the intention-to-treat analysis, the rate of treatment success was 75% among patients randomly assigned to bracing, as compared with 42% among those randomly assigned to observation (odds ratio, 4.11; 95% CI, 1.85 to 9.16). There was a significant positive association between hours of brace wear and rate of treatment success (P CONCLUSIONS: Bracing significantly decreased the progression of high-risk curves to the threshold for surgery in patients with adolescent idiopathic scoliosis. The benefit increased with longer hours of brace wear. (Funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and others; BRAIST ClinicalTrials.gov number, NCT00448448opens in new tab.)</p

    Bioactive nutrients - Time for tolerable upper intake levels to address safety.

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    There is increasing interest by consumers, researchers, and regulators into the roles that certain bioactive compounds, derived from plants and other natural sources, can play in health maintenance and promotion, and even prolonging a productive quality of life. Research has rapidly emerged suggesting that a wide range of compounds and mixtures in and from plants (such as fruits and vegetables, tea and cocoa) and animals (such as fish and probiotics) may exert substantial health benefits. There is interest in exploring the possibility of establishing recommended intakes or dietary guidance for certain bioactive substances to help educate consumers. A key aspect of establishing dietary guidance is the assessment of safety/toxicity of these substances. Toxicologists need to be involved in both the development of the safety framework and in the evaluation of the science to establish maximum intake/upper limits

    Measuring the Intangible Values of Natural Streams, Part II

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    This report describes the work done during Part II of a project which had as its aim the development of a way to quantify those intangible values peculiar to a small stream and its watershed. Part I was concerned with an application of the uniqueness concept in the evaluation of fifty-eight Kentucky streams. The results of this effort are in Report #40, U. K. Water Resources Institute (1971). During the second part of the project: A method was developed whereby peoples\u27 preferences for natural landscapes could be measured. The method utilized projected color slides and a rating system based on the semantic differential. Fourteen preference studies were conducted using different types of subjects and stimuli (color slides). The data were factor analyzed and scores computed for three factors (Natural Beauty, Force and Starkness) for each slide-subject group combination. The scenic content of each slide was measured and related to the factor scores by a series of linear regression equations. The uniqueness ratio approach was modified to include fewer stream characteristics (thirty-seven) and the work of Part I essentially repeated. A new method of stream evaluation was developed which yields a factor score for a given stream on each of six factors (Scenic Attractiveness, Land Use-Topo, Litter, Aquatic Habitat, Extractive Industry, Development). Conclusions were as follows: A scene that includes a view of running water is usually preferred over one that includes still water or no water at all. The stark beauty of a desert, lava flow or a winter pasture is not perceived by most people. Some types of visual pollution (i.e.; misfit billboards) are not recognized as such by some groups of people. Familiar scenes are not considered particularly beautiful even though they may be so to outsiders. Occupation and life style seem to have more effect on an individual\u27s concept of natural beauty than age or sex. People agree on what\u27s very beautiful or very ugly in a scene but disagree on the in-between. The semantic differential method as applied in this study yields measures of preference that are well-correlated with on-site evaluations by competent judges. Predicting preference from the physical content of a scene yields only approximate results. Reducing the number of stream characteristics used to compute uniqueness ratios did not greatly change the uniqueness rankings of the fifty-eight study streams. The recommended procedure for evaluating small streams is the factor score approach supplemented by a carefully conceived and executed preference study. The procedure should be applied to a random sample of all small streams in a state or region to establish a stream hierarchy. Factor scores and/ or rankings for a given stream could, if desired, be worked into a benefit-cost or other such computation in the form of a weight or multiplier

    Examining EdD Dissertations in Practice: The Carnegie Project on the Education Doctorate

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    In 2007, 25 colleges and schools of education (Phase I) came together under the aegis of the Carnegie Project on the Education Doctorate (CPED) to transform doctoral education for education practitioners. A challenging aspect of the reform of the educational doctorate is the role and design of the dissertation or Dissertation in Practice. In response to consortium concerns, members of the CPED Dissertation in Practice Awards Committee conducted this action research study to examine the format and design of Dissertations in Practice submitted by (re) designed programs. Data were gathered with an online survey, interviews, analyses of 25 Dissertations in Practice submitted in 2013 to the Committee. Results indicated few changes occurred in the final product, despite evidence of change in the Dissertation in Practice process. Findings contribute to debates about the distinctive nature of EdDs (and of professional doctorates generally) as distinct from PhDs, and how about the key criteria for demonstrating “new knowledge to solve significant problems of practice” are demonstrated through the dissertation submission

    Efficient, full-spectrum, long-lived, non-toxic microwave lamp for plant growth

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    Fusion Systems Corporation has developed a mercury-free, low infrared, efficient microwave lamp using a benign sulfur based fill optimized for visible light. Our literature search and discussions with researchers directed us to enhance the bulbs red output. We have demonstrated a photosynthetic efficacy of over 2 micro-moles per microwave joule which corresponds to over 1.3 micro-moles per joule at the power main. Recent work has shown we can make additional increases in overall system efficiency. During the next two years, we expect to demonstrate a system capable of producing more than 1.5 micro-moles/joule measured at the power main with significantly less IR than alternative lamp systems. We determined optimal plant growth light requirements via a literature search and researcher input. We surveyed candidate lamp fill materials to be used in combination with sulfur and explored several methods of increasing photosynthetic efficacy

    "Contemplating the next maneuver": functional neuroimaging reveals intraoperative decision-making strategies

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    OBJECTIVE: To investigate differences in the quality, confidence, and consistency of intraoperative surgical decision making (DM) and using functional neuroimaging expose decision systems that operators use. SUMMARY BACKGROUND DATA: Novices are hypothesized to use conscious analysis (effortful DM) leading to activation across the dorsolateral prefrontal cortex, whereas experts are expected to use unconscious automation (habitual DM) in which decisions are recognition-primed and prefrontal cortex independent. METHODS: A total of 22 subjects (10 medical student novices, 7 residents, and 5 attendings) reviewed simulated laparoscopic cholecystectomy videos, determined the next safest operative maneuver upon video termination (10 s), and reported decision confidence. Video paradigms either declared ("primed") or withheld ("unprimed") the next operative maneuver. Simultaneously, changes in cortical oxygenated hemoglobin and deoxygenated hemoglobin inferring prefrontal activation were recorded using Optical Topography. Decision confidence, consistency (primed vs unprimed), and quality (script concordance) were assessed. RESULTS: Attendings and residents were significantly more certain (P < 0.001), and decision quality was superior (script concordance: attendings = 90%, residents = 78.3%, and novices = 53.3%). Decision consistency was significantly superior in experts (P < 0.001) and residents (P < 0.05) than novices (P = 0.183). During unprimed DM, novices showed significant activation of the dorsolateral prefrontal cortex, whereas this activation pattern was not observed among residents and attendings. During primed DM, significant activation was not observed in any group. CONCLUSIONS: Expert DM is characterized by improved quality, consistency, and confidence. The findings imply attendings use a habitual decision system, whereas novices use an effortful approach under uncertainty. In the presence of operative cues (primes), novices disengage the prefrontal cortex and seem to accept the observed operative decision as correct

    Polarization-Insensitive Medium-Switchable Holographic Metasurfaces

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    The adoption of metasurfaces has led to revolutionary advances in holography due to improved compactness, integrability, and performance. Switchable meta-holograms projecting different replay field images in a controllable manner are highly desirable. Still, existing technologies generally rely on the use of polarized light and additional optics to facilitate switching. Consequently, the potential benefits afforded through the use of metasurfaces are limited both by the system complexity and a fixed relationship between the optical input and output. In this manuscript, we demonstrate polarization-insensitive metasurfaces encoding arbitrary and independent holograms, which can be switched between by changing the refractive index of the infiltration medium while maintaining identical illumination conditions. By sidestepping the requirements for high-performance light sources, switching optics, or delicate alignment, this approach points toward ultracompact and cost-effective switchable meta-holograms for various practical applications, such as holographic image projection, eye-perceptible sensors, optical information storage, processing, and security

    Bubbling AdS and droplet descriptions of BPS geometries in IIB supergravity

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    This paper focuses on supergravity duals of BPS states in N=4 super Yang-Mills. In order to describe these duals, we begin with a sequence of breathing mode reductions of IIB supergravity: first on S^3, then S^3 x S^1, and finally on S^3 x S^1 x CP^1. We then follow with a complete supersymmetry analysis, yielding 1/8, 1/4 and 1/2 BPS configurations, respectively (where in the last step we take the Hopf fibration of S^3). The 1/8 BPS geometries, which have an S^3 isometry and are time-fibered over a six-dimensional base, are determined by solving a non-linear equation for the Kahler metric on the base. Similarly, the 1/4 BPS configurations have an S^3 x S^1 isometry and a four-dimensional base, whose Kahler metric obeys another non-linear, Monge-Ampere type equation. Despite the non-linearity of the problem, we develop a universal bubbling AdS description of these geometries by focusing on the boundary conditions which ensure their regularity. In the 1/8 BPS case, we find that the S^3 cycle shrinks to zero size on a five-dimensional locus inside the six-dimensional base. Enforcing regularity of the full solution requires that the interior of a smooth, generally disconnected five-dimensional surface be removed from the base. The AdS_5 x S^5 ground state corresponds to excising the interior of an S^5, while the 1/8 BPS excitations correspond to deformations (including topology change) of the S^5 and/or the excision of additional droplets from the base. In the case of 1/4 BPS configurations, by enforcing regularity conditions, we identify three-dimensional surfaces inside the four-dimensional base which separate the regions where the S^3 shrinks to zero size from those where the S^1 shrinks.Comment: 94 pages, 6 figures, latex, typos corrected, references added, one new Appendi
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