1,266 research outputs found
Structured computer-based training in the interpretation of neuroradiological images
Computer-based systems may be able to address a recognised need throughout the medical profession for a more structured approach to training. We describe a combined training system for neuroradiology, the MR Tutor that differs from previous approaches to computer-assisted training in radiology in that it provides case-based tuition whereby the system and user communicate in terms of a well-founded Image Description Language. The system implements a novel method of visualisation and interaction with a library of fully described cases utilising statistical models of similarity, typicality and disease categorisation of cases. We describe the rationale, knowledge representation and design of the system, and provide a formative evaluation of its usability and effectiveness
Proprioceptive feedback facilitates motor imagery-related operant learning of sensorimotor β-band modulation
Motor imagery (MI) activates the sensorimotor system independent of actual movements and might be facilitated by neurofeedback. Knowledge on the interaction between feedback modality and the involved frequency bands during MI-related brain self-regulation is still scarce. Previous studies compared the cortical activity during the MI task with concurrent feedback (MI with feedback condition) to cortical activity during the relaxation task where no feedback was provided (relaxation without feedback condition). The observed differences might, therefore, be related to either the task or the feedback. A proper comparison would necessitate studying a relaxation condition with feedback and a MI task condition without feedback as well. Right-handed healthy subjects performed two tasks, i.e., MI and relaxation, in alternating order. Each of the tasks (MI vs. relaxation) was studied with and without feedback. The respective event-driven oscillatory activity, i.e., sensorimotor desynchronization (during MI) or synchronization (during relaxation), was rewarded with contingent feedback. Importantly, feedback onset was delayed to study the task-related cortical activity in the absence of feedback provision during the delay period. The reward modality was alternated every 15 trials between proprioceptive and visual feedback. Proprioceptive input was superior to visual input to increase the range of task-related spectral perturbations in the α- and β-band, and was necessary to consistently achieve MI-related sensorimotor desynchronization (ERD) significantly below baseline. These effects occurred in task periods without feedback as well. The increased accuracy and duration of learned brain self-regulation achieved in the proprioceptive condition was specific to the β-band. MI-related operant learning of brain self-regulation is facilitated by proprioceptive feedback and mediated in the sensorimotor β-band
Up and down the number line: modelling collaboration in contrasting school and home environments
This paper is concerned with user modelling issues such as adaptive educational environments, adaptive information retrieval, and support for collaboration. The HomeWork project is examining the use of learner modelling strategies within both school and home environments for young children aged 5 – 7 years. The learning experience within the home context can vary considerably from school especially for very young learners, and this project focuses on the use of modelling which can take into account the informality and potentially contrasting learning styles experienced within the home and school
A methodology for the capture and analysis of hybrid data: a case study of program debugging
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Potential of a hybrid wind-diesel-compressed air system for nordic remote canadian areas
In Canada, off-grid power production is significant, with more than 200,000 people living in about 300 remote
communities scattered across Yukon, the Northwest Territories, Nunavut, and other islands. Most of these isolated sites rely on diesel to generate electricity. The operation of these remote isolated grids run on a deficit in the order of hundreds of millions of dollars yearly and must therefore be subsidized by the government. Low and high penetration wind–diesel hybrid systems (WDS) have been experimented to reduce diesel consumption. In a previous article, we explored the re-engineering of current diesel power plants with the introduction of high penetration wind systems using compressed air energy storage (CAES). This is a viable alternative to increase the overall percentage of
renewable energy and reduce the cost of electricity, to increase the diesel engine lifetime and efficiency and to
decrease their fuel consumption and GHG emissions. In this paper, we present the operative principle of this hybrid system, its economic benefits and advantages. Finally, we apply this concept in the case of a Canadian Nordic village to demonstrate the real energetic, ecological and economic potential of this system
Four Butterflies: End of Life Stories of Transition and Transformation
In this article, the author discusses her experiences as an Artist In Residence in the
Department of Palliative Care and Rehabilitation Medicine at the University of Texas M. D.
Anderson Cancer Center. Emphasis is placed on the ways in which end of life images and
narratives often unfold in the fragile yet powerful space where conceptions of aesthetics and
spirituality intersect with critical issues in the medical humanities. Drawing on four vivid
case studies, the author examines the ways in which end of life narratives shed valuable light on
conceptions of the subtlety of human embodiment; issues of violation, sorrow, and forgiveness;
the mystical dimensions of traditional cultural beliefs; and the capacity for perceiving the
natural world as a living symbol of grace. In so doing, she explores how the themes of transition
and transformation become invested with meaningful existential and symbolic dimensions in
artworks that give voice and presence to some of the most vulnerable, and often invisible,
members of our societyďľ—people at the end of life
Pulse-shape discrimination and energy resolution of a liquid-argon scintillator with xenon doping
Liquid-argon scintillation detectors are used in fundamental physics
experiments and are being considered for security applications. Previous
studies have suggested that the addition of small amounts of xenon dopant
improves performance in light or signal yield, energy resolution, and particle
discrimination. In this study, we investigate the detector response for xenon
dopant concentrations from 9 +/- 5 ppm to 1100 +/- 500 ppm xenon (by weight) in
6 steps. The 3.14-liter detector uses tetraphenyl butadiene (TPB) wavelength
shifter with dual photomultiplier tubes and is operated in single-phase mode.
Gamma-ray-interaction signal yield of 4.0 +/- 0.1 photoelectrons/keV improved
to 5.0 +/- 0.1 photoelectrons/keV with dopant. Energy resolution at 662 keV
improved from (4.4 +/- 0.2)% ({\sigma}) to (3.5 +/- 0.2)% ({\sigma}) with
dopant. Pulse-shape discrimination performance degraded greatly at the first
addition of dopant, slightly improved with additional additions, then rapidly
improved near the end of our dopant range, with performance becoming slightly
better than pure argon at the highest tested dopant concentration. Some
evidence of reduced neutron scintillation efficiency with increasing dopant
concentration was observed. Finally, the waveform shape outside the TPB region
is discussed, suggesting that the contribution to the waveform from
xenon-produced light is primarily in the last portion of the slow component
A Study of the Residual 39Ar Content in Argon from Underground Sources
The discovery of argon from underground sources with significantly less 39Ar
than atmospheric argon was an important step in the development of
direct-detection dark matter experiments using argon as the active target. We
report on the design and operation of a low background detector with a single
phase liquid argon target that was built to study the 39Ar content of the
underground argon. Underground argon from the Kinder Morgan CO2 plant in
Cortez, Colorado was determined to have less than 0.65% of the 39Ar activity in
atmospheric argon.Comment: 21 pages, 10 figure
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