1,032 research outputs found

    Learning to Read, Learning to Love It: A Shared Literacy Vision

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    THE DETERMINATION OF NITRATE IN GREEN TOMATO AND LETTUCE TISSUES

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    Employment Trends in Communication Arts and Sciences

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    This article looks at the career opportunities for communication arts and sciences graduates in the U.S. As graduate students planning academic careers seek counsel for their programs of study, there is a need for good answers regarding career opportunities. Departments planning curricula and seeking to fill position vacancies likewise require reliable information regarding the directions in which their disciplines are moving. The analysis for curricula development, program growth, and career choices requires more than anecdotal evidence. Incidental conversations at conventions and the occasional reviews of the state of the art are helpful, but not adequate for considering concerns as important as academic hiring. Frameworks for assessing employment trends in higher education have been offered by Matyas and Martin (1998) and others. Specific to the communication discipline, Andersen (1997) discussed trends in graduate education and their implications for hiring. In an attempt to provide further evidence for systematic assessment of hiring choices made by higher education communication programs, the present study follows the lead of Ross and Emmert (1987) and others. It also examines the current job market in the Communication Arts and Sciences, as indicated by positions listed in the Classified Ads of Spectra, the newsletter of the National Communication Association. Although there are other media for position announcements, Spectra remains the principle means for job soliciting in the Communication Arts and Sciences

    Impact of imperfect test sensitivity on determining risk factors : the case of bovine tuberculosis

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    Background Imperfect diagnostic testing reduces the power to detect significant predictors in classical cross-sectional studies. Assuming that the misclassification in diagnosis is random this can be dealt with by increasing the sample size of a study. However, the effects of imperfect tests in longitudinal data analyses are not as straightforward to anticipate, especially if the outcome of the test influences behaviour. The aim of this paper is to investigate the impact of imperfect test sensitivity on the determination of predictor variables in a longitudinal study. Methodology/Principal Findings To deal with imperfect test sensitivity affecting the response variable, we transformed the observed response variable into a set of possible temporal patterns of true disease status, whose prior probability was a function of the test sensitivity. We fitted a Bayesian discrete time survival model using an MCMC algorithm that treats the true response patterns as unknown parameters in the model. We applied our approach to epidemiological data of bovine tuberculosis outbreaks in England and investigated the effect of reduced test sensitivity in the determination of risk factors for the disease. We found that reduced test sensitivity led to changes to the collection of risk factors associated with the probability of an outbreak that were chosen in the ‘best’ model and to an increase in the uncertainty surrounding the parameter estimates for a model with a fixed set of risk factors that were associated with the response variable. Conclusions/Significance We propose a novel algorithm to fit discrete survival models for longitudinal data where values of the response variable are uncertain. When analysing longitudinal data, uncertainty surrounding the response variable will affect the significance of the predictors and should therefore be accounted for either at the design stage by increasing the sample size or at the post analysis stage by conducting appropriate sensitivity analyses

    Rule-based Approach for Arabic Root Extraction: New Rules to Directly Extract Roots of Arabic Words

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    Extracting word roots in Arabic language is very problematic due to the specific morphological and structural changes in the language. To address this problem, several techniques have been proposed. This paper continues the problem of identifying and exploiting relationship amongst Arabic letters for Arabic root extraction begun in [1]. Eight different rules that detect the root letters according to other letters in the word have been proposed and tested, four of them benefiting from the idea of morphological substitution (MUTATION). The approach has been evaluated using the Holy Quran words. The evaluation results show a promising root extraction algorithm

    Memantine and cholinesterase inhibitor combination therapy for Alzheimer's disease: a systematic review

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    BACKGROUND: Memantine is licensed for moderate-to-severe Alzheimer's disease (AD). National Institute for Clinical Excellence (NICE) guidance does not recommend the use of memantine in combination with cholinesterase inhibitors (acetylcholinesterase inhibitor (AChEI)). The underpinning meta-analysis was disputed by the manufacturer. OBJECTIVES: To compare the efficacy of AChEI monotherapy with combination memantine and AChEI therapy in patients with moderate-to-severe AD and to examine the impact of including unpublished data on the results. DESIGN: Systematic review and meta-analysis of randomised controlled trials. DATA SOURCES: The Cochrane Dementia Group trial register, ALOIS, searched for the last time on 3 May 2011. DATA SYNTHESIS: Data from four domains (clinical global, cognition, function, behaviour and mood) were pooled. Sensitivity analyses examined the impact on the NICE-commissioned meta-analysis of restricting data to patients with moderate-to-severe AD and of including an unpublished trial of an extended release preparation of memantine. RESULTS: Pooled data from the trials, which were included in the NICE-commissioned meta-analysis but which were restricted to moderate-to-severe AD only, showed a small effect of combination therapy on cognition (standardised mean difference (SMD)=-0.29, 95% CI -0.45 to -0.14). Adding data from an unpublished trial of an extended release memantine (total three trials, 1317 participants) showed a small benefit of combination therapy on global scores (SMD=-0.20, 95% CI -0.31 to -0.09), cognition (SMD=-0.25, 95% CI -0.36 to -0.14) and behaviour and mood (SMD=-0.17, 95% CI -0.32 to -0.03) but not on function (SMD=-0.04, 95% CI -0.21 to 0.13) at 6 months. No clinical data have been reported from a 1-year trial, although this found 'no significant benefit' on any clinical measures at 1 year. CONCLUSIONS: These results suggest that there may be a small benefit at 6 months of adding memantine to AChEIs. However, the impact on clinical global impression depends on exactly which studies are included, and there is no benefit on function, so its clinical relevance is not robustly demonstrated. Currently available information from randomised controlled trails indicates no benefit of combination therapy over monotherapy at 1 year. Legislation on the form and content of registry posted results is needed in Europe

    Effects of Internal Configuration on Afterburner Shell Temperatures

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    A brief investigation was conducted in the altitude wind tunnel to determine the extent to which the afterburner shell cooling problem could be alleviated by internal configuration changes. Data were obtained with and without a cooling liner installed and for variations in the radial fuel distribution and in the radial distribution in flame-seat area. Consideration is given to the effects on both shell temperature and afterburner performance. In the range of fuel-air ratio investigated, the use of a cooling liner resulted in substantial reductions in shell temperature with no penalty in performance. Appreciable reductions in afterburner shell temperature were made possible by control of the radial fuel distribution; however, the effects on performance are uncertain and may depend on other variables not investigated. No direct relation was found between shell temperature and the clearance between the flame holder and the shell; however, some cooling effect may possibly be achieved by varying the clearance

    Full-scale Investigation of Cooling Shroud and Ejector Nozzle for a Turbojet Engine : Afterburner Installation

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    A full-scale ejector cooling investigation was made on a turbojet engine - afterburner installation in the NACA Lewis altitude wind tunnel. Ejector performance was studied at primary exhaust-gas temperatures from 2700 degrees to 3400 degrees R (corresponding to ejector temperature ratios from 2.0 to 5.0), primary pressure ratios from 1.79 to 3.4, secondary air flows up to 29 percent of the primary gas flow, and for diameter ratios from 1.08 to 1.42 and spacing ratios from 0.04 to 1.16. In addition, variations were made in the primary exhaust-nozzle area. Ejectors with large diameter ratios permit the attainment of high gas flow ratios, but the jet-thrust losses become prohibitive as the spacing ratio is increased from 0 to 0.16. As the ejector diameter is reduced, the obtainable gas-flow ratio and the thrust loss are reduced. Previous results showing that data obtained at a temperature ratio of 1.0 could not be extrapolated to determine ejector performance at high temperature ratios by the application of the temperature ratio factor to the gas-flow ratios are substantiated by the present investigation
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