12,930 research outputs found

    Stereomobilization performance norms of children ages 10 to 12

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    Stereomobilization improves upon standard stereopsis measurements by utilizing temporal effects in the assessment of depth perception. Studies using optometry students have been performed to establish adult norms (Thompson and Yudcovitch, 1996 and Jahner and Moffit, 1998) and norms for jet fighter pilots (Brotherson, Rhoton, and Tipton, 1997). To create standard values for a younger population, 21 middle school students ages 10 to 12 were studied using the same protocol as the adult studies. The stereomobilization values for a disparity of 450 were not significantly different from these adult studies, but were superior in performance to the pilots studied. At 125 ms and faster, stereomobility was still operating above levels of chance or guessing

    Design Space Exploration of the Violacein Pathway in Escherichia coli Based Transcription Translation Cell-Free System (TX-TL)

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    In this study, an Escherichia coli (E. coli) based transcription translation cell-free system (TX-TL) was employed to sample various enzyme expression levels of the violacein pathway. The pathway was successfully reconstructed in TX-TL. Its variation produced different metabolites as evident from the extracts assorted colors. Analysis of the violacein product via UV-Vis absorption and liquid chromatography-mass spectrometry (LC-MS) detected 68 nanograms of violacein per 10 microliters reaction volume. Significant buildup of prodeoxyviolacein intermediate was also detected in the equimolar TX-TL reaction. Finally, design space exploration experiments suggested an improvement in violacein production at high VioC and VioD DNA concentrations

    A Comparative Economic Analysis for Cloud Computing

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    Analyzing the economic viability of using cloud computing services within an organization is an important aspect for business today. Significant cost savings can be obtained through selecting the best net benefit alternative between the defender and multiple challengers of business technology systems being considered. A simple definition of cloud computing is the use of software systems and storage accessed through the Internet. Traditionally, these services are managed and provided from in-house, on-site systems. There are several cloud computing service providers to choose from. This study provides an economic comparison between on-site, Amazon Web Services, and the Google Cloud Platform. This analysis uses present worth, and the minimum attractive rate of return using a five (5) year time-frame. A benefit-cost analysis is provided to determine if the efficiency ratios warrant viability of each alternative. An incremental analysis follows, using each viable alternative to find the best option that provides the highest net benefit to the firm. Outcomes from this methodology will vary depending on the specifics of the alternatives being examined. In this example scenario, a fully remote, cloud computing based company is the recommended strategy to pursue

    Development of a Psychologically Enhanced Interactive Online Intervention for Hazardous Drinking

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    Aims: The content of novel interventions is often not well specified. We provide a detailed account of the rationale for and redevelopment of an Internet resource for hazardous drinkers—Down Your Drink (DYD) (www.downyourdrink.org.uk). Development Work: An iterative process blended literature reviews of Internet interventions for health conditions and brief treatments for alcohol problems, feedback from users of the original site and from users panels, and completion of a series of developmental tasks. Intervention: The detailed structure and content of the new version of the website is presented. This permits an appreciation of the intended interaction between the user and the intervention, and emphasizes both the freedom of choice available to the user to access diverse material for personal benefit and the value of a clear organizational structure. Conclusions: Presentation of detailed information on the theoretical underpinning, content and structure of an intervention makes it easier to interpret the results of any evaluation and is likely to be of use to those developing other online interventions for alcohol or other health behaviours

    Particle stabilized water in water emulsions

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    Food products often contain mixtures of incompatible water soluble macromolecules such as proteins and polysaccharides. When two aqueous solutions of incompatible macromolecules are mixed they separate into two phases each enriched in one of the two macromolecules. Contrary to oil-water (O/W) emulsions, water/water (W/W) emulsions cannot be stabilized by addition of surfactants and in food applications macroscopic phase separation is avoided by gelling one or both phases. However, recently it was shown that W/W emulsions can be stabilized to varying extents by addition of particles. Such particle stabilized emulsions are also known as Pickering emulsions and have been studied extensively for O/W emulsions. Here the literature on particle stabilization of W/W emulsions is reviewed. The behavior of particle stabilized W/W emulsions is found to be quite different from that of O/W emulsions due to the much smaller interfacial tension and the much larger length scale at which the interface expresses itself. Besides the particle size, interaction of the particles with the macromolecules in the mixture and with each other at the interface appears to play a decisive role for stabilization

    VARIANCE INFLATION FACTORS IN REGRESSION MODELS WITH DUMMY VARIABLES

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    Variance Inflation Factors (VIFs) are used to detect collinearity among predictors in regression models. Textbook explanation of collinearity and diagnostics such as VIFs have focused on numeric predictors as being co-linear or co-planar , with little attention paid to VIFs when a dummy variable is included in the model. This work was motivated by two regression models with high VIFs, where standard\u27 interpretations of causes of collinearity made no sense. The first was an alfalfa-breeding model with two numeric predictors and two dummy variables. The second was an economic model with one numeric predictor, one dummy and the numeric x dummy cross-product. This paper gives formulas for VIFs for several regression models with a dummy variable which indicate that these VIFs are functions of the numeric predictors\u27 means, sums of squares and sample sizes within the two dummy groups. The economic regression model is also presented to illustrate how high VIFs occurred in this data. Researchers should be cautious in using high VIFs as a reason for deleting predictors in general but especially if dummy variables are involved. It is recommended that collinearity diagnostics be applied to the numeric predictors first to check for collinearity without the influence of any dummies, then add dummy variables in one at a time to see their effect on VIFs

    Dust-Gas Scaling Relations and OH Abundance in the Galactic ISM

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    Observations of interstellar dust are often used as a proxy for total gas column density NHN_\mathrm{H}. By comparing Planck\textit{Planck} thermal dust data (Release 1.2) and new dust reddening maps from Pan-STARRS 1 and 2MASS (Green et al. 2018), with accurate (opacity-corrected) HI column densities and newly-published OH data from the Arecibo Millennium survey and 21-SPONGE, we confirm linear correlations between dust optical depth τ353\tau_{353}, reddening E(B−V)E(B{-}V) and the total proton column density NHN_\mathrm{H} in the range (1−-30)×\times1020^{20}cm−2^{-2}, along sightlines with no molecular gas detections in emission. We derive an NHN_\mathrm{H}/E(B−V)E(B{-}V) ratio of (9.4±\pm1.6)×\times1021^{21}cm−2^{-2}mag−1^{-1} for purely atomic sightlines at ∣b∣|b|>>5∘^{\circ}, which is 60%\% higher than the canonical value of Bohlin et al. (1978). We report a ∌\sim40%\% increase in opacity σ353\sigma_{353}=τ353\tau_{353}/NHN_\mathrm{H}, when moving from the low column density (NHN_\mathrm{H}<<5×\times1020^{20}cm−2^{-2}) to moderate column density (NHN_\mathrm{H}>>5×\times1020^{20}cm−2^{-2}) regime, and suggest that this rise is due to the evolution of dust grains in the atomic ISM. Failure to account for HI opacity can cause an additional apparent rise in σ353\sigma_{353}, of the order of a further ∌\sim20%\%. We estimate molecular hydrogen column densities NH2N_{\mathrm{H}_{2}} from our derived linear relations, and hence derive the OH/H2_2 abundance ratio of XOHX_\mathrm{OH}∌\sim1×\times10−7^{-7} for all molecular sightlines. Our results show no evidence of systematic trends in OH abundance with NH2N_{\mathrm{H}_{2}} in the range NH2N_{\mathrm{H}_{2}}∌\sim(0.1−-10)×\times1021^{21}cm−2^{-2}. This suggests that OH may be used as a reliable proxy for H2_2 in this range, which includes sightlines with both CO-dark and CO-bright gas.Comment: The revised manuscript is accepted for publication in The Astrophysical Journa

    A bioinformatics workflow for detecting signatures of selection in genomic data

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    The detection of “signatures of selection” is now possible on a genome-wide scale in many plant and animal species, and can be performed in a population-specific manner due to the wealth of per-population genome-wide genotype data that is available. With genomic regions that exhibit evidence of having been under selection shown to also be enriched for genes associated with biologically important traits, detection of evidence of selective pressure is emerging as an additional approach for identifying novel gene-trait associations. While high-density genotype data is now relatively easy to obtain, for many researchers it is not immediately obvious how to go about identifying signatures of selection in these data sets. Here we describe a basic workflow, constructed from open source tools, for detecting and examining evidence of selection in genomic data. Code to install and implement the pipeline components, and instructions to run a basic analysis using the workflow described here, can be downloaded from our public GitHub repository: http://www.github.com/smilefreak/selectionTools
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