465 research outputs found

    A Critique of “Gamification” in Khan Academy

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    Khan Academy (Kahn Acadamy, 2013) is an informal online learning platform that is adding game elements that participants encounter as they move through curricula. This “gamification”, includes the addition of badges, accomplishment statistics and skill tree visualizations that reflect the completion of different learning task and participation in the online community. In this paper we outline the types of gamification used in Khan academy and reflect on their effectiveness in relation to learning theory and motivation theory

    Information Seeking Practices of Parents: Exploring Skills, Face Threats and Social Networks

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    Parents are often responsible for finding, selecting, and facilitating their children\u27s out-of-school learning experiences. One might expect that the recent surge in online educational tools and the vast online network of information about informal learning would make this easier for all parents. Instead, the increase in these free, accessible resources is contributing to an inequality of use between children from lower and higher socio-economic status (SES). Through over 60 interviews with a diverse group of parents, we explored parents\u27 ability to find learning opportunities and their role in facilitating educational experiences for their children. We identified differences in the use of online social networks in finding learning opportunities for their children based on SES. Building upon these findings, we conducted a national survey in partnership with ACT, an educational testing services organization, to understand if these differences were generalizable to and consistent among a broader audience

    Getter sputtering system for high-throughput fabrication of composition spreads

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    We describe a sputtering system that can deposit composition spreads in an effectively UHV environment but which does not require the high-throughput paradigm to be compromised by a long pump down each time a target is changed. The system deploys four magnetron sputter guns in a cryoshroud (getter sputtering) which allows elements such as Ti and Zr to be deposited with minimal contamination by oxygen or other reactive background gases. The system also relies on custom substrate heaters to give rapid heating and cool down. The effectiveness of the gettering technique is evaluated, and example results obtained for catalytic activity of a pseudoternary composition spread are presented

    Getter sputtering system for high-throughput fabrication of composition spreads

    Get PDF
    We describe a sputtering system that can deposit composition spreads in an effectively UHV environment but which does not require the high-throughput paradigm to be compromised by a long pump down each time a target is changed. The system deploys four magnetron sputter guns in a cryoshroud (getter sputtering) which allows elements such as Ti and Zr to be deposited with minimal contamination by oxygen or other reactive background gases. The system also relies on custom substrate heaters to give rapid heating and cool down. The effectiveness of the gettering technique is evaluated, and example results obtained for catalytic activity of a pseudoternary composition spread are presented

    Design, Participation, and Social Change: What Design in Grassroots Spaces Can Teach Learning Scientists

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    hile a science of design (and theory of learning) is certainly useful in design-based research, a participatory design research framework presents an opening for learning scientists to rethink design and learning as processes. Grounded in the autoethnographic investigation of a grassroots organization\u27s design of a local campaign, the author traces the successive transformations of design artifacts, delineating a narrative character to design within grassroots spaces. One major lesson is that centering the question of participation is not just about including historically marginalized peoples at the core of design; it has the potential to “desettle” projects at a fundamental level, challenging dominant epistemologies that inform the practices of learning scientists, and thus transforming the field in ways that have yet to be systematically explored. More broadly, this study highlights the need for future research on design practices as they take form within understudied spaces, such as grassroots organizations

    Reappraising myocardial fibrosis in severe aortic stenosis: an invasive and non-invasive study in 133 patients

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    Aims: To investigate myocardial fibrosis (MF) in a large series of severe aortic stenosis (AS) patients using invasive biopsy and non-invasive imaging. Methods and results: One hundred thirty-three patients with severe, symptomatic AS accepted for surgical aortic valve replacement underwent cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume fraction (ECV) quantification. Intra-operative left ventricular (LV) biopsies were performed by needle or scalpel, yielding tissue with (n = 53) and without endocardium (n = 80), and compared with 10 controls. Myocardial fibrosis occurred in three patterns: (i) thickened endocardium with a fibrotic layer; (ii) microscopic scars, with a subendomyocardial predominance; and (iii) diffuse interstitial fibrosis. Collagen volume fraction (CVF) was elevated (P < 0.001) compared with controls, and higher (P < 0.001) in endocardium-containing samples with a decreasing CVF gradient from the subendocardium (P = 0.001). Late gadolinium enhancement correlated with CVF (P < 0.001) but not ECV. Both LGE and ECV correlated independently (P < 0.001) with N-terminal pro-brain natriuretic peptide and high-sensitivity-troponin T. High ECV was also associated with worse LV remodelling, left ventricular ejection fraction and functional capacity. Combining high ECV and LGE better identified patients with more adverse LV remodelling, blood biomarkers and histological parameters, and worse functional capacity than each parameter alone. Conclusion: Myocardial fibrosis in severe AS is complex, but three main patterns exist: endocardial fibrosis, microscars (mainly in the subendomyocardium), and diffuse interstitial fibrosis. Neither histological CVF nor the CMR parameters ECV and LGE capture fibrosis in its totality. A combined, multi-parametric approach with ECV and LGE allows best stratification of AS patients according to the response of the myocardial collagen matrix

    Half-metallic antiferromagnets in thiospinels

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    We have theoretically designed the half-metallic (HM) antiferromagnets (AFMs) in thiospinel systems, Mn(CrV)S4\rm Mn(CrV)S_{4} and Fe0.5Cu0.5(V0.5Ti1.5)S4\rm Fe_{0.5}Cu_{0.5}(V_{0.5}Ti_{1.5})S_{4}, based on the electronic structure studies in the local-spin-density approximation (LSDA). We have also explored electronic and magnetic properties of parent spinel compounds of the above systems; CuV2S4\rm CuV_{2}S_{4} and CuTi2S4\rm CuTi_{2}S_{4} are found to be HM ferromagnets in their cubic spinel structures, while MnCr2S4\rm MnCr_{2}S_{4} is a ferrimagnetic insulator. We have discussed the feasibility of material synthesis of HM-AFM thiospinel systems.Comment: 4 pages, 5 figure

    Virtual models of care for people with palliative care needs living in their own home: A systematic meta-review and narrative synthesis.

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    Background: Access to palliative care in the community enables people to live in their preferred place of care, which is often home. Community palliative care services struggle to provide timely 24-h services to patients and family. This has resulted in calls for ‘accessible and flexible’ models of care that are ‘responsive’ to peoples’ changing palliative care needs. Digital health technologies provide opportunities to meet these requirements 24-h a day. Aim: To identify digital health technologies that have been evaluated for supporting timely assessment and management of people living at home with palliative care needs and/or their carer(s), and the evidence-base for each. Design: A systematic review of systematic reviews (‘meta-review’). Systematic reviews evaluating evidence for virtual models of palliative or end-of-life care using one or more digital health technologies were included. Systematic reviews were evaluated using the Risk of Bias Tool for Systematic Reviews. A narrative approach was used to synthesise results. Data sources:Medline, Embase, Web of Science, CINAHL and Cochrane Database of systematic reviews were searched for English-language reviews published between 2015 and 2020. Results: The search yielded 2266 articles, of which 12 systematic reviews met criteria. Sixteen reviews were included in total, after four reviews were found via handsearching. Other than scheduled telehealth, video-conferencing, or after-hours telephone support, little evidence was found for digital health technologies used to deliver virtual models of palliative care. Conclusions: There are opportunities to test new models of virtual care, beyond telehealth and/or video conferencing, such as 24-h command centres, and rapid response teams

    An electrochemical system for efficiently harvesting low-grade heat energy

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    Efficient and low-cost thermal energy-harvesting systems are needed to utilize the tremendous low-grade heat sources. Although thermoelectric devices are attractive, its efficiency is limited by the relatively low figure-of-merit and low-temperature differential. An alternative approach is to explore thermodynamic cycles. Thermogalvanic effect, the dependence of electrode potential on temperature, can construct such cycles. In one cycle, an electrochemical cell is charged at a temperature and then discharged at a different temperature with higher cell voltage, thereby converting heat to electricity. Here we report an electrochemical system using a copper hexacyanoferrate cathode and a Cu/Cu2+ anode to convert heat into electricity. The electrode materials have low polarization, high charge capacity, moderate temperature coefficients and low specific heat. These features lead to a high heat-to-electricity energy conversion efficiency of 5.7% when cycled between 10 and 60 degrees C, opening a promising way to utilize low-grade heat.open121
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