4,477 research outputs found

    Understanding object feature binding through experimentation as a precursor to modelling

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    In order to explore underlying brain mechanisms and to further understand how and where object feature binding occurs, psychophysical data are analysed and will be modelled using an attractor network. This paper describes psychophysical work and an outline of the proposed model. A rapid serial visual processing paradigm with a post-cue response task was used in three experimental conditions: spatial, temporal and spatio-temporal. Using a ‘staircase’ procedure, stimulus onset asynchrony for each observer for each condition was set in practice trails to achieve ~50% error rates. Results indicate that spatial location information helps bind objects features and temporal location information hinders it. Our expectation is that the proposed neural model will demonstrate a binding mechanism by exhibiting regions of enhanced activity in the location of the target when presented with a partial post-cue. In future work, the model could be lesioned so that neuropsychological phenomena might be exhibited. In such a way, the mechanisms underlying object feature binding might be clarified

    Measurements of Grain Motion in a Dense, Three-Dimensional Granular Fluid

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    We have used an NMR technique to measure the short-time, three-dimensional displacement of grains in a system of mustard seeds vibrated vertically at 15g. The technique averages over a time interval in which the grains move ballistically, giving a direct measurement of the granular temperature profile. The dense, lower portion of the sample is well described by a recent hydrodynamic theory for inelastic hard spheres. Near the free upper surface the mean free path is longer than the particle diameter and the hydrodynamic description fails.Comment: 4 pages, 4 figure

    Recent Experiences of Tunneling and Deep Excavations in London

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    The paper focuses on recent developments in tunnelling and deep excavations in London and it draws on the experiences of the Jubilee Line Extension project which has just been completed. A brief historical review is given of the first tunnels and deep excavations undertaken in London some 150 years ago. Construction methods recently used for bored tunnelling include sprayed concrete linings and closed face pressurised tunnelling machines. Ground movements observed for these various tunnelling operations and for deep excavations are reviewed, and their effects on buildings are discussed. The most extensive protective measure used on the Jubilee Line Extension to control deformations and potential damage to historic buildings has been the relatively new technique of compensation grouting. Examples of its use are presented

    A Computer Graphics Head-Up Display for Air-To-Air and Air-To-Ground Flight Simulation

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    A computer graphics simulation of an aircraft Head-Up Display was designed using an RDS-3000 Ikonas Graphics Processor and a PDP-11/34 host computer system. The software control and display modules were accomplished using Ikonas microcode and Digital Equipment Corporation Fortran IV-PLUS. The Head-Up Display system consists of the basic flight data, which includes aerodynamic flight information, Roll/Pitch Ladder, and the Velocity Vector or Flight Path Marker. The system was designed for flexibility in modifications and evaluation of various weapons delivery systems. These will be adapted to specific needs by research scientists and engineers at the Visual Technology Research Simulator in Orlando, Florida

    Evaluation of existing and new methods of tracking glacier terminus change

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    ACKNOWLEDGEMENTS The authors thank two anonymous reviewers for constructive comments that helped to improve the manuscript. This research was financially supported by J.M.L.’s PhD funding from UK Natural Environment Research Council grant No. NE/I528742/1.Peer reviewedPublisher PD

    Pharmacist intervention in primary care to improve outcomes in patients with left ventricular systolic dysfunction

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    <b>Background</b> Meta-analysis of small trials suggests that pharmacist-led collaborative review and revision of medical treatment may improve outcomes in heart failure.<p></p> <b>Methods and results</b> We studied patients with left ventricular systolic dysfunction in a cluster-randomized controlled, event driven, trial in primary care. We allocated 87 practices (1090 patients) to pharmacist intervention and 87 practices (1074 patients) to usual care. The intervention was delivered by non-specialist pharmacists working with family doctors to optimize medical treatment. The primary outcome was a composite of death or hospital admission for worsening heart failure. This trial is registered, number ISRCTN70118765. The median follow-up was 4.7 years. At baseline, 86% of patients in both groups were treated with an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. In patients not receiving one or other of these medications, or receiving less than the recommended dose, treatment was started, or the dose increased, in 33.1% of patients in the intervention group and in 18.5% of the usual care group [odds ratio (OR) 2.26, 95% CI 1.64–3.10; P< 0.001]. At baseline, 62% of each group were treated with a β-blocker and the proportions starting or having an increase in the dose were 17.9% in the intervention group and 11.1% in the usual care group (OR 1.76, 95% CI 1.31–2.35; P< 0.001). The primary outcome occurred in 35.8% of patients in the intervention group and 35.4% in the usual care group (hazard ratio 0.97, 95% CI 0.83–1.14; P = 0.72). There was no difference in any secondary outcome.<p></p> <b>Conclusion</b> A low-intensity, pharmacist-led collaborative intervention in primary care resulted in modest improvements in prescribing of disease-modifying medications but did not improve clinical outcomes in a population that was relatively well treated at baseline
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