629 research outputs found

    A Classification of Infographics

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    Classifications are useful for describing existing phenomena and guiding further investigation. Several classifications of diagrams have been proposed, typically based on analytical rather than empirical methodologies. A notable exception is the work of Lohse and his colleagues, published in Communications of the ACM in December 1994. The classification of diagrams that Lohse proposed was derived from bottom-up grouping data collected from sixteen participants and based on 60 diagrams. Mean values on ten Likert-scales were used to predict diagram class. We follow a similar methodology to Lohse, using real-world infographics (i.e. embellished data charts) as our stimuli. We propose a structural classification of infographics, and determine whether infographics class can be predicted from values on Likert scales

    Urine lipoarabinomannan testing for diagnosis of pulmonary tuberculosis in children: a prospective study

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    Background Urine tests for mycobacterial lipoarabinomannan might be useful for point-of-care diagnosis of tuberculosis in adults with advanced HIV infection, but have not been assessed in children. We assessed the accuracy of urine lipoarabinomannan testing for the diagnosis of pulmonary tuberculosis in HIV-positive and HIV-negative children. Methods We prospectively recruited children (aged ≤15 years) who presented with suspected tuberculosis at a primary health-care clinic and paediatric referral hospital in South Africa, between March 1, 2009, and April 30, 2012. We assessed the diagnostic accuracy of urine lipoarabinomannan testing with lateral fl ow assay and ELISA, with mycobacterial culture of two induced sputum samples as the reference standard. Positive cultures were identifi ed by acid-fast staining and tested to confi rm Mycobacterium tuberculosis and establish susceptibility to rifampicin and isoniazid. Findings 535 children (median age 42·5 months, IQR 19·1–66·3) had urine and two induced specimens available for testing. 89 (17%) had culture-confi rmed tuberculosis and 106 (20%) had HIV. The lateral fl ow lipoarabinomannan test showed poor accuracy against the reference standard, with sensitivity of 48·3% (95% CI 37·6–59·2), specifi city of 60·8% (56·1–65·3), and an area under the receiver operating characteristic curve of 0·53 (0·46–0·60) for children without HIV and 0·64 (0·51–0·76) for children with HIV. ELISA had poor sensitivity in children without HIV (sensitivity 3·0%, 95% CI 0·4–10·5) and children with HIV (0%, 0·0–14·3); overall specifi city was 95·7% (93·4–97·4). Interpretation Urine lipoarabinomannan tests have insuffi cient sensitivity and specifi city to diagnose HIV-positive and HIV-negative children with tuberculosis and should not be used in this patient population

    Sampling reactive pathways with random walks in chemical space: Applications to molecular dissociation and catalysis

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    Automatically generating chemical reaction pathways is a significant computational challenge, particularly in the case where a given chemical system can exhibit multiple reactants and products, as well as multiple pathways connecting these. Here, we outline a computational approach to allow automated sampling of chemical reaction pathways, including sampling of different chemical species at the reaction end-points. The key features of this scheme are (i) introduction of a Hamiltonian which describes a reaction “string” connecting reactant and products, (ii) definition of reactant and product species as chemical connectivity graphs, and (iii) development of a scheme for updating the chemical graphs associated with the reaction end-points. By performing molecular dynamics sampling of the Hamiltonian describing the complete reaction pathway, we are able to sample multiple different paths in configuration space between given chemical products; by periodically modifying the connectivity graphs describing the chemical identities of the end-points we are also able to sample the allowed chemical space of the system. Overall, this scheme therefore provides a route to automated generation of a “roadmap” describing chemical reactivity. This approach is first applied to model dissociation pathways in formaldehyde, H2CO, as described by a parameterised potential energy surface (PES). A second application to the HCo(CO)3 catalyzed hydroformylation of ethene (oxo process), using density functional tight-binding to model the PES, demonstrates that our graph-based approach is capable of sampling the intermediate paths in the commonly accepted catalytic mechanism, as well as several secondary reactions. Further algorithmic improvements are suggested which will pave the way for treating complex multi-step reaction processes in a more efficient manner

    Employers and schools: how Mansfield is building a world of work approach

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    There is a keen interest in encouraging employers to engage with schools so that young people can learn more about careers, understand the skills that employers are interested in, broaden their aspirations and be motivated to succeed. Employer engagement in schools in England however is increasingly fragmented because of a loss of brokering infrastructure. This article describes a partnership approach developed in Mansfield where a consortium of local schools has worked with their business community and public sector organisations. Together they have listened to what young people say they both want and need to know about careers and then responded by providing a strategic careers learning programme. The particular contribution of the Mansfield Learning Partnership which is wholly funded by the town’s secondary schools is detailed in the article alongside elaboration of the Mansfield Framework for Career Learning which provides a work experience programme and several imaginative opportunities for young people to engage in meaningful encounters with employers

    Chaotic dynamics of falling disks

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    The study of the motion of flat bodies falling in a viscous medium dates back at least to Newton(1) and Maxwell(2), and is relevant to problems in meteorology(3), sedimentology(4), aerospace engineering(1) and chemical engineering(5-8). More recent theoretical studies(9-12) have emphasized the role played by deterministic chaos, although many experimental studies(1,5-8,13,14) were performed before the development of such ideas. Here we report experimental observations of the dynamics of disks falling in water/glycerol mixtures. We find four distinct types of motion, which are mapped out in a 'phase diagram'. The apparently complex behaviour can be reduced to a series of one-dimensional maps, which display a discontinuity at the crossover from periodic to chaotic motion. This discontinuity leads to an unusual intermittency transition(15), not previously observed experimentally, between the two behaviours.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62793/1/388252a0.pd

    Mineral chemistry of igneous melanite garnets from analcite-bearing volcanic rocks, Alberta, Canada

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    The mineral chemistry of melanite garnets from the Crowsnest volcanic rocks of SW Alberta, Canada, has been investigated by using electron microprobe scans, quantitative analyses and multivariate statistical analysis. The garnets occur with aegirine-augite, sanidine, analcite and rare plagioclase as phenocrysts in trachyte and phonolite flows, agglomerates and tuffs. Wavelength dispersive microprobe scans reveal complex zonation patterns, both normal and oscillatory. The results of fifty quantitative analyses were subjected to R-mode factor analysis to delineate the chemical exchanges producing the zonation. The chemical zonation of the garnets may be attributed to four independent binary exchanges; Al-Fe3+, Si-Ti, Ca-Mn and Mg-Fe2+. The stoichiometry of these garnets, based on microprobe and wet chemical Fe analyses, combined with the strongly antithetic behavior of Si and Ti lead us to infer that the Ti in these garnets is dominantly tetravalent. It is clear from this study that quantitative modelling of the processes of crystal growth and zonation of melanite garnets in alkaline, undersaturated igneous rocks should be aimed at simulating the four chemical exchanges listed above

    Real Time Animation of Virtual Humans: A Trade-off Between Naturalness and Control

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    Virtual humans are employed in many interactive applications using 3D virtual environments, including (serious) games. The motion of such virtual humans should look realistic (or ‘natural’) and allow interaction with the surroundings and other (virtual) humans. Current animation techniques differ in the trade-off they offer between motion naturalness and the control that can be exerted over the motion. We show mechanisms to parametrize, combine (on different body parts) and concatenate motions generated by different animation techniques. We discuss several aspects of motion naturalness and show how it can be evaluated. We conclude by showing the promise of combinations of different animation paradigms to enhance both naturalness and control
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