31,752 research outputs found

    Photographic investigation of propellant stream behavior in a firing rocket engine, volume I Technical summary report, 1 Aug. 1964 - 28 Feb. 1966

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    Photographic study to obtain injection and combustion patterns of F-1 rocket engine injector element

    Sketchy rendering for information visualization

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    We present and evaluate a framework for constructing sketchy style information visualizations that mimic data graphics drawn by hand. We provide an alternative renderer for the Processing graphics environment that redefines core drawing primitives including line, polygon and ellipse rendering. These primitives allow higher-level graphical features such as bar charts, line charts, treemaps and node-link diagrams to be drawn in a sketchy style with a specified degree of sketchiness. The framework is designed to be easily integrated into existing visualization implementations with minimal programming modification or design effort. We show examples of use for statistical graphics, conveying spatial imprecision and for enhancing aesthetic and narrative qualities of visual- ization. We evaluate user perception of sketchiness of areal features through a series of stimulus-response tests in order to assess users’ ability to place sketchiness on a ratio scale, and to estimate area. Results suggest relative area judgment is compromised by sketchy rendering and that its influence is dependent on the shape being rendered. They show that degree of sketchiness may be judged on an ordinal scale but that its judgement varies strongly between individuals. We evaluate higher-level impacts of sketchiness through user testing of scenarios that encourage user engagement with data visualization and willingness to critique visualization de- sign. Results suggest that where a visualization is clearly sketchy, engagement may be increased and that attitudes to participating in visualization annotation are more positive. The results of our work have implications for effective information visualization design that go beyond the traditional role of sketching as a tool for prototyping or its use for an indication of general uncertainty

    Sexual offender’s experiences of polygraph testing: a thematic study in three probation trusts

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    Post-conviction polygraph testing of sexual offenders is controversial and the use of the polygraph as a means of supporting supervision of sexual offenders has only recently been explored. This study quantitatively examined qualitatively offender managers’ and sexual offenders’ views on the mandatory use of the polygraph in a community-based supervision. Fifteen polygraphed offenders and their 10 offender managers (polygraph group), and 10 non-polygraphed offenders and their ten offender managers (comparison group) were asked about their experiences and perceptions of a mandatory polygraph use. Using thematic analysis, the results provided four main themes: (1) truth detection, (2) perceptions of behaviour change, (3) perceptions of polygraph as part of supervision, and (4) national implementation of polygraph testing. Results suggest several benefits to mandatory polygraph testing as a support for supervision, including offenders making more high-risk disclosures, motivating offender honesty, and aiding offenders’ compliance with licence conditions

    Understanding AGB evolution in Galactic bulge stars from high-resolution infrared spectroscopy

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    An analysis of high-resolution near-infrared spectra of a sample of 45 asymptotic giant branch (AGB) stars towards the Galactic bulge is presented. The sample consists of two subsamples, a larger one in the inner and intermediate bulge, and a smaller one in the outer bulge. The data are analysed with the help of hydrostatic model atmospheres and spectral synthesis. We derive the radial velocity of all stars, and the atmospheric chemical mix ([Fe/H], C/O, 12^{12}C/13^{13}C, Al, Si, Ti, and Y) where possible. Our ability to model the spectra is mainly limited by the (in)completeness of atomic and molecular line lists, at least for temperatures down to Teff≈3100T_{\rm eff}\approx3100 K. We find that the subsample in the inner and intermediate bulge is quite homogeneous, with a slightly sub-solar mean metallicity and only few stars with super-solar metallicity, in agreement with previous studies of non-variable M-type giants in the bulge. All sample stars are oxygen-rich, C/O<<1.0. The C/O and carbon isotopic ratios suggest that third dredge-up (3DUP) is absent among the sample stars, except for two stars in the outer bulge that are known to contain technetium. These stars are also more metal-poor than the stars in the intermediate or inner bulge. Current stellar masses are determined from linear pulsation models. The masses, metallicities and 3DUP behaviour are compared to AGB evolutionary models. We conclude that these models are partly in conflict with our observations. Furthermore, we conclude that the stars in the inner and intermediate bulge belong to a more metal-rich population that follows bar-like kinematics, whereas the stars in the outer bulge belong to the metal-poor, spheroidal bulge population.Comment: 21 pages, 13 figures, 6 tables (incl. appendix), years of work, published in MNRA

    Variation in the transfer of radionuclide to freshwater fish: phylogeny or feeding strategy?

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    For both terrestrial vascular plants and marine organisms if has been demonstrated the differences in radionuclide transfer between species can be related to their evolutionary history or phylogeny. Relationships between phylogeny and radionuclide transfer offer a potential approach to help to derive best estimate values if data for a given species-radionuclide are not available. In this paper we describe the analyses of data for radionuclide transfer to freshwater fish from a data base recently compiled to support activities of both the IAEA and ICRP. There are sufficient data in the database to test the hypothesis that radionuclide transfer can be related to the evolutionary of freshwater fish for caesium, strontium and uranium. For instance, the database contains 750 entries for caesium considering nearly 70 species of fish. Initial results indicate that phylogeny does explain some of the variation in radionuclide transfer between species of fish. However, feeding strategy also explains variation in radionuclide transfer between species. In this paper we will compare our results to establish if phylogeny or feeding strategy is the most useful predictor of radionuclide transfer to freshwater fish

    Fast calibrated additive quantile regression

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    We propose a novel framework for fitting additive quantile regression models, which provides well calibrated inference about the conditional quantiles and fast automatic estimation of the smoothing parameters, for model structures as diverse as those usable with distributional GAMs, while maintaining equivalent numerical efficiency and stability. The proposed methods are at once statistically rigorous and computationally efficient, because they are based on the general belief updating framework of Bissiri et al. (2016) to loss based inference, but compute by adapting the stable fitting methods of Wood et al. (2016). We show how the pinball loss is statistically suboptimal relative to a novel smooth generalisation, which also gives access to fast estimation methods. Further, we provide a novel calibration method for efficiently selecting the 'learning rate' balancing the loss with the smoothing priors during inference, thereby obtaining reliable quantile uncertainty estimates. Our work was motivated by a probabilistic electricity load forecasting application, used here to demonstrate the proposed approach. The methods described here are implemented by the qgam R package, available on the Comprehensive R Archive Network (CRAN)

    Evolving social dynamics prime thermal tolerance during a poleward range shift

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