28,985 research outputs found

    The effect of pulse rate on vacuum phototriodes response and the use of an LED pulser to improve stability

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    The official published version of this paper can be found at the link below.The Endcap Electromagnetic Calorimeter of the Compact Muon Solenoid detector (CMS) at the Large Hadron Collider (LHC) uses vacuum phototriodes (VPTs), which operate in the full 3.8T magnetic field of the experiment, to detect the scintillation light from the lead tungstate crystals. Initial measurements of the variation in response of VPTs, induced by sudden changes in the illuminating light pulse rate, prompted the inclusion of a dedicated stability pulser based on light emitting diodes (LEOs). The response of production VPTs, under simulated LHC operating conditions, has been investigated in three independent studies: in-situ tests with the installed endcaps at CERN, and separate VPT studies by groups at the University of Virginia, USA and Brunel University, UK. In this work, results are presented which illustrate the magnitude of the effect to demonstrate the expected stability of the VPTs during normal LHC operation, with a proposed regime for operating the stability pulser to minimise variations in response. It is demonstrated that a continuous signal at a rate of 100Hz is sufficient to reduce the change in the VPT response to <0.2%

    Bromegrass in Alaska. I.Winter Survival and Forage Productivity of Bromus Species, Types, and Cultivars as Related to Latitudinal Adaptation

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    This report summarizes seven separate field experiments, conducted over more than two decades at the University of Alaska’s Matanuska Research Farm, that compared strains within three bromegrass (Bromus) species for winter hardiness and forage production. Species were (a) smooth bromegrass (B. inermis Leyss.), (b) native Alaskan pumpelly bromegrass (B. pumpellianus Scribn.), and (c) meadow bromegrass (B. biebersteinii Roem. and Schult.), a species native to southwestern Asia

    Widening Participation in Golf: Barriers to Participation and GolfMark

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    This research was commissioned by the EGU and R&A in 2010. The aims of the research project were threefold: 1) To review the academic literature on barriers to participation in sport, especially golf; 2) To survey clubs, members and nomadic golfers to describe their perceptions of GolfMark and the issues it intends to address; 3) To gather in-depth data from a range of golf clubs to help understand how different club cultures may lead to the exclusion of underrepresented demographic groups

    Contemporary database topics:learning by teaching

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    Passive learning is generally believed to be ineffectual in that it leads to a generally impoverished student experience manifested by poor attendance, engagement and motivation alike. A shift towards a more pro-active learning experience was therefore the main motivator for the proposed method outlined in this paper. The method adopted was applied to a single module for a cohort of postgraduate, mainly international students. In our method, each student is charged with delivering a specialist database topic as part of an allocated group. They self-organise their group into two sub-groups for lecture and tutorial delivery respectively. Staff support the process by delivering the teaching in the first half of the module. The second, student-led phase is staff-supported using preparatory meetings to discuss content and presentation issues prior to delivery. Feedback overall indicates that the method is effective, particularly in confidence building. We believe that the latter more than compensates for the one or two concerns raised about the quality of information being received. We conclude by discussing a number of changes based on two years’ experience and student feedback

    Upper critical dimension of the KPZ equation

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    Numerical results for the Directed Polymer model in 1+4 dimensions in various types of disorder are presented. The results are obtained for system size considerably larger than that considered previously. For the extreme strong disorder case (Min-Max system), associated with the Directed Percolation model, the expected value of the meandering exponent, zeta = 0.5 is clearly revealed, with very week finite size effects. For the week disorder case, associated with the KPZ equation, finite size effects are stronger, but the value of seta is clearly seen in the vicinity of 0.57. In systems with "strong disorder" it is expected that the system will cross over sharply from Min-Max behavior at short chains to weak disorder behavior at long chains. This is indeed what we find. These results indicate that 1+4 is not the Upper Critical Dimension (UCD) in the week disorder case, and thus 4+1 does not seem to be the upper critical dimension for the KPZ equation

    Wave-like spread of Ebola Zaire

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    In the past decade the Zaire strain of Ebola virus (ZEBOV) has emerged repeatedly into human populations in central Africa and caused massive die-offs of gorillas and chimpanzees. We tested the view that emergence events are independent and caused by ZEBOV variants that have been long resident at each locality. Phylogenetic analyses place the earliest known outbreak at Yambuku, Democratic Republic of Congo, very near to the root of the ZEBOV tree, suggesting that viruses causing all other known outbreaks evolved from a Yambuku-like virus after 1976. The tendency for earlier outbreaks to be directly ancestral to later outbreaks suggests that outbreaks are epidemiologically linked and may have occurred at the front of an advancing wave. While the ladder-like phylogenetic structure could also bear the signature of positive selection, our statistical power is too weak to reach a conclusion in this regard. Distances among outbreaks indicate a spread rate of about 50 km per year that remains consistent across spatial scales. Viral evolution is clocklike, and sequences show a high level of small-scale spatial structure. Genetic similarity decays with distance at roughly the same rate at all spatial scales. Our analyses suggest that ZEBOV has recently spread across the region rather than being long persistent at each outbreak locality. Controlling the impact of Ebola on wild apes and human populations may be more feasible than previously recognized

    Online learning and fun with databases

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    In this paper, we explore how online learning can support face-to-face teaching in fundamental database theory and the contributions it can make towards motivating and enhancing the student learning experience. We show how we have used WebCT for a third level database module and present student feedback to our approach. While online participation is high overall, motivation for self-learning is increased by the use of self-assessment exercises and summative assessment was also considered to be more fun online than using paper based equivalents. Evidence exists to link greater online participation of course materials to improved performance. We complement our feedback by presenting and discussing a number of software tools which help students practice important methods in database systems, including SQL. After evaluating these against known methods for improving student motivation, we suggest ideas for further development of more game-like learning tools

    Linking recorded data with emotive and adaptive computing in an eHealth environment

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    Telecare, and particularly lifestyle monitoring, currently relies on the ability to detect and respond to changes in individual behaviour using data derived from sensors around the home. This means that a significant aspect of behaviour, that of an individuals emotional state, is not accounted for in reaching a conclusion as to the form of response required. The linked concepts of emotive and adaptive computing offer an opportunity to include information about emotional state and the paper considers how current developments in this area have the potential to be integrated within telecare and other areas of eHealth. In doing so, it looks at the development of and current state of the art of both emotive and adaptive computing, including its conceptual background, and places them into an overall eHealth context for application and development

    Towards the improvement of self-service systems via emotional virtual agents

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    Affective computing and emotional agents have been found to have a positive effect on human-computer interactions. In order to develop an acceptable emotional agent for use in a self-service interaction, two stages of research were identified and carried out; the first to determine which facial expressions are present in such an interaction and the second to determine which emotional agent behaviours are perceived as appropriate during a problematic self-service shopping task. In the first stage, facial expressions associated with negative affect were found to occur during self-service shopping interactions, indicating that facial expression detection is suitable for detecting negative affective states during self-service interactions. In the second stage, user perceptions of the emotional facial expressions displayed by an emotional agent during a problematic self-service interaction were gathered. Overall, the expression of disgust was found to be perceived as inappropriate while emotionally neutral behaviour was perceived as appropriate, however gender differences suggested that females perceived surprise as inappropriate. Results suggest that agents should change their behaviour and appearance based on user characteristics such as gender
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