1,642 research outputs found

    Conceptions of geographic information systems (GIS) held by senior geography students in Queensland

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    Geographical Information Systems (GIS) represent one of the major contributions to spatial analysis and planning of the new technologies. While teachers and others have viewed its potential contribution to geographical education as considerable, it has not been known with any certainty whether they present a valuable educational tool that aids geographical education. The value of GIS to geographical education is viewed as depending on a geographical education being, in itself, valuable. Within this context, synergetic focus groups are employed to explore the conceptions of GIS held by 109 secondary school students studying Senior Geography in metropolitan and regional Queensland, Australia. A phenomenographic approach is adopted to identify the six qualitatively different ways, or conceptions, in which the participating students experience GIS as: 1. Maps and a source of maps in geography. 2. Mapping in geography: a way to use and create maps. 3. A professional mapping tool: exceeding the needs of senior geography. 4. Frustrating geography: irksome and presenting many challenges to the student-user. 5. Relevant geography: within and beyond the school experience. 6. A better geography: offering a superior curriculum, and broader geographical education, when contrasted to a senior geography that omits its use. The structural and referential elements of each of these conceptions are elucidated within corresponding Categories of Description. The qualitatively different ways in which the conceptions may be experienced are illustrated through an Outcome Space, comprising a metaphoric island landscape. This structural framework reveals that for the Senior Geography students who participated in this investigation, the extent to which GIS may augment the curriculum is influenced by the nature of students' individual understandings of how GIS manages spatial data. This research project is a response to repeated calls in the literature for teachers of geography themselves to become researchers and for a better understanding of GIS within geography education. It reviews the salient literature with respect to geography and geography education generally, and GIS within geographical education specifically. The investigation has confirmed that qualitatively different conceptions of GIS exist amongst students and that these are not consistently aligned with assumptions about its use and benefits as presented by current literature. The findings of the study contribute to knowledge of the potential educational outcomes associated with the use of GIS in geography education and decisions related to current and potential geography curricula. It provides guidance for future curriculum development involving GIS and argues for additional research to inform educators and the spatial sciences industry about the actual and perceived role of GIS within geography education

    No effect of arm exercise on diaphragmatic fatigue or ventilatory constraint in Paralympic athletes with cervical spinal cord injury

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    Cervical spinal cord injury (CSCI) results in a decrease in the capacity of the lungs and chest wall for pressure, volume, and airflow generation. We asked whether such impairments might increase the potential for exercise-induced diaphragmatic fatigue and mechanical ventilatory constraint in this population. Seven Paralympic wheelchair rugby players (mean ± SD peak oxygen uptake = 16.9 ± 4.9 ml·kg–1·min–1) with traumatic CSCI (C5–C7) performed arm-crank exercise to the limit of tolerance at 90% of their predetermined peak work rate. Diaphragm function was assessed before and 15 and 30 min after exercise by measuring the twitch transdiaphragmatic pressure (Pdi,tw) response to bilateral anterolateral magnetic stimulation of the phrenic nerves. Ventilatory constraint was assessed by measuring the tidal flow volume responses to exercise in relation to the maximal flow volume envelope. Pdi,tw was not different from baseline at any time after exercise (unpotentiated Pdi,tw = 19.3 ± 5.6 cmH2O at baseline, 19.8 ± 5.0 cmH2O at 15 min after exercise, and 19.4 ± 5.7 cmH2O at 30 min after exercise; P = 0.16). During exercise, there was a sudden, sustained rise in operating lung volumes and an eightfold increase in the work of breathing. However, only two subjects showed expiratory flow limitation, and there was substantial capacity to increase both flow and volume (<50% of maximal breathing reserve). In conclusion, highly trained athletes with CSCI do not develop exercise-induced diaphragmatic fatigue and rarely reach mechanical ventilatory constraint

    Uncertainty Quantification and Certification Prediction of Low-Boom Supersonic Aircraft Configurations

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    The primary objective of this work was to develop and demonstrate a process for accurate and efficient uncertainty quantification and certification prediction of low-boom, supersonic, transport aircraft. High-fidelity computational fluid dynamics models of multiple low-boom configurations were investigated including the Lockheed Martin SEEB-ALR body of revolution, the NASA 69 Delta Wing, and the Lockheed Martin 1021-01 configuration. A nonintrusive polynomial chaos surrogate modeling approach was used for reduced computational cost of propagating mixed, inherent (aleatory) and model-form (epistemic) uncertainty from both the computation fluid dynamics model and the near-field to ground level propagation model. A methodology has also been introduced to quantify the plausibility of a design to pass a certification under uncertainty. Results of this study include the analysis of each of the three configurations of interest under inviscid and fully turbulent flow assumptions. A comparison of the uncertainty outputs and sensitivity analyses between the configurations is also given. The results of this study illustrate the flexibility and robustness of the developed framework as a tool for uncertainty quantification and certification prediction of low-boom, supersonic aircraft

    Solar system science with the Wide-Field Infrared Survey Telescope

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    We present a community-led assessment of the solar system investigations achievable with NASA’s next-generation space telescope, the Wide Field Infrared Survey Telescope (WFIRST). WFIRST will provide imaging, spectroscopic, and coronagraphic capabilities from 0.43 to 2.0  μm and will be a potential contemporary and eventual successor to the James Webb Space Telescope (JWST). Surveys of irregular satellites and minor bodies are where WFIRST will excel with its 0.28  deg^2 field-of-view Wide Field Instrument. Potential ground-breaking discoveries from WFIRST could include detection of the first minor bodies orbiting in the inner Oort Cloud, identification of additional Earth Trojan asteroids, and the discovery and characterization of asteroid binary systems similar to Ida/Dactyl. Additional investigations into asteroids, giant planet satellites, Trojan asteroids, Centaurs, Kuiper belt objects, and comets are presented. Previous use of astrophysics assets for solar system science and synergies between WFIRST, Large Synoptic Survey Telescope, JWST, and the proposed Near-Earth Object Camera mission is discussed. We also present the case for implementation of moving target tracking, a feature that will benefit from the heritage of JWST and enable a broader range of solar system observations

    Manipulating ultracold atoms with a reconfigurable nanomagnetic system of domain walls

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    The divide between the realms of atomic-scale quantum particles and lithographically-defined nanostructures is rapidly being bridged. Hybrid quantum systems comprising ultracold gas-phase atoms and substrate-bound devices already offer exciting prospects for quantum sensors, quantum information and quantum control. Ideally, such devices should be scalable, versatile and support quantum interactions with long coherence times. Fulfilling these criteria is extremely challenging as it demands a stable and tractable interface between two disparate regimes. Here we demonstrate an architecture for atomic control based on domain walls (DWs) in planar magnetic nanowires that provides a tunable atomic interaction, manifested experimentally as the reflection of ultracold atoms from a nanowire array. We exploit the magnetic reconfigurability of the nanowires to quickly and remotely tune the interaction with high reliability. This proof-of-principle study shows the practicability of more elaborate atom chips based on magnetic nanowires being used to perform atom optics on the nanometre scale.Comment: 4 pages, 4 figure
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