5,374 research outputs found

    Vicarious learning through capturing task‐directed discussions

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    The vicarious learner group has been developing a multimedia database system to promote and enhance the role of dialogue in learning. A specific interest, and the origin of the projects' collective name, is in the question of whether and how dialogue can be helpfully ‘reused’. What benefits can students gain from dialogue as observers, not just as participants? We describe our initial attempts to generate and capture educationally effective discourse exchanges amongst and between students and tutors. Problems encountered with available CMC discourse formats led to our development of a set of Task Directed Discussions (TDDs). A medium‐sized corpus of discourse exchanges was collected using the TDDs. A selection of nearly two hundred of these TDD exchanges formed the multimedia discourse database to the implemented prototype system, Dissemination. Initial results from a controlled experiment and evaluation of Dissemination are outline

    Interior noise levels of two propeller-driven light aircraft

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    The relationships between aircraft operating conditions and interior noise and the degree to which ground testing can be used in lieu of flight testing for performing interior noise research were studied. The results show that the noise inside light aircraft is strongly influenced by the rotational speed of the engine and propeller. Both the overall noise and low frequency spectra levels were observed to decrease with increasing high speed rpm operations during flight. This phenomenon and its significance is not presently understood. Comparison of spectra obtained in flight with spectra obtained on the ground suggests that identification of frequency components and relative amplitude of propeller and engine noise sources may be evaluated on stationary aircraft

    Change in background context disrupts performance on visual paired comparison following hippocampal damage

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    The medial temporal lobe plays a critical role in recognition memory but, within the medial temporal lobe, the precise neural structures underlying recognition memory remain equivocal. in this study, visual paired comparison (VPC) was used to investigate recognition memory in a human patient (YR), who had a discrete lesion of the hippocampus, and a group of monkeys with neonatal hippocampal lesions, which included the dentate gyrus, and a portion of parahippocampal region. Participants were required to view a picture of an object on a coloured background. Immediately afterwards, this familiar object was shown again, this time paired with a novel object. All participants displayed a novelty preference, provided the background on which the objects were shown was the same as the one used during the learning phase. When the background of the familiar object was changed between initial familiarization and test, only the control subjects showed a novelty preference; the hippocampal-lesioned monkeys and patient YR showed null preference. The results are interpreted within Eichenbaum and Bunsey's [Eichenbaum, H., & Bunsey, M. (1995). On the binding of associations in memory: Clues from studies on the role of the hippocampal region in paired-associate learning. Current Directions in Psychological Science, 4, 19-23] proposal that the hippocampus facilitates the formation of a flexible representation of the elements that make up a stimulus whereas the parahippocampal region is involved in the formation of a fused representation. (C) 2009 Elsevier Ltd. All rights reserved

    Memoirs of a trainer : The search for a balance between quality and best practice

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    The field of research training (for students and supervisors) is becoming more heavily regulated by the Federal Government. At the same time, quality improvement imperatives are requiring staff across the University to have better access to information and knowledge about a wider range of activities each year. Within the Creative Industries Faculty at the Queensland University of Technology (QUT), the training provided to academic and research staff is organised differently and individually. This session will involve discussion of the dichotomies found in this differentiated approach to staff training, and begin a search for best practice through interaction and input from the audience

    Identifying pathways of exposure to highway pollutants in great crested newt (Triturus cristatus) road mitigation tunnels: Exposure pathways of highway pollutants to Triturus cristatus

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    Road mitigation tunnels are increasingly deployed for amphibians but very little is known about chemical pollution in such schemes. We assessed pollution pressures associated with road runoff at a major great crested newt mitigation scheme in England. Sediments and waters in the mitigation system were analysed for major physico-chemical parameters, trace metals and total petroleum hydrocarbons and compared to a nearby reference site. Seven out of eight tested metals including copper, zinc, lead and iron were in significantly greater concentrations in the tunnels than at a reference site and at environmentally significant concentrations. Water samples also exhibited elevated concentrations of aluminium and chromium and occasionally extreme alkaline pH associated with leaching of portlandite in tunnel cements. High conductivity values in waters and sediments corresponding with seasonal de-icing salt application were also apparent. The study highlights the potential pollutant pressures for amphibians associated with large-scale urban development and road mitigation schemes

    Multiple safety net regulators and agency problems in the European Union: Is prompt corrective action partly the solution?

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    This paper discusses the institutional changes needed in Europe if prompt corrective action (PCA) is to be effective in supervising and resolving cross-border banking groups. The paper identifies these changes starting with enhancements in the availability of information on banking groups’ financial condition to prudential supervisors. Next, the paper considers the collective decision making by prudential supervisors with authority to make discretionary decisions within the PCA framework as soon as a bank in a cross-border banking group falls below the minimum capital standard. Finally, the paper analyzes the coordination measures that should be implemented if PCA requires the bank to be resolved.

    Exact 1-D Model for Coherent Synchrotron Radiation with Shielding and Bunch Compression

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    Coherent Synchrotron Radiation has been studied effectively using a 1-dimensional model for the charge distribution in the realm of small angle approximations and high energies. Here we use Jefimenko's form of Maxwell's equations, without such approximations, to calculate the exact wake-fields due to this effect in multiple bends and drifts. It has been shown before that the influence of a drift can propagate well into a subsequent bend. We show, for reasonable parameters, that the influence of a previous bend can also propagate well into a subsequent bend, and that this is especially important at the beginning of a bend. Shielding by conducting parallel plates is simulated using the image charge method. We extend the formalism to situations with compressing and decompressing distributions, and conclude that simpler approximations to bunch compression usually overestimates the effect. Additionally, an exact formula for the coherent power radiated by a Gaussian bunch is derived by considering the coherent synchrotron radiation spectrum, and is used to check the accuracy of wake-field calculations

    Effects of aircraft noise on flight and ground structures

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    Acoustic loads measured on jet-powered STOL configurations are presented for externally blown and upper surface blown flap models ranging in size from a small laboratory model up to a full-scale aircraft model. The implications of the measured loads for potential acoustic fatigue and cabin noise are discussed. Noise transmission characteristics of light aircraft structures are presented. The relative importance of noise transmission paths, such as fuselage sidewall and primary structure, is estimated. Acceleration responses of a historic building and a residential home are presented for flyover noise from subsonic and supersonic aircraft. Possible effects on occupant comfort are assessed. The results from these three examples show that aircraft noise can induce structural responses that are large enough to require consideration in the design or operation of the aircraft

    Hypothesis:soluble Aβ oligomers in association with redox-active metal ions are the optimal generators of reactive oxygen species in Alzheimer's disease

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    Considerable evidence points to oxidative stress in the brain as an important event in the early stages of Alzheimer's disease (AD). The transition metal ions of Cu, Fe, and Zn are all enriched in the amyloid cores of senile plaques in AD. Those of Cu and Fe are redox active and bind to Aβ in vitro. When bound, they can facilitate the reduction of oxygen to hydrogen peroxide, and of the latter to the hydroxyl radical. This radical is very aggressive and can cause considerable oxidative damage. Recent research favours the involvement of small, soluble oligomers as the aggregating species responsible for Aβ neurotoxicity. We propose that the generation of reactive oxygen species (i.e., hydrogen peroxide and hydroxyl radicals) by these oligomers, in association with redox-active metal ions, is a key molecular mechanism underlying the pathogenesis of AD and some other neurodegenerative disorders
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