512 research outputs found

    Building End-User Thesauri from Full-Text

    Get PDF
    We are interested in the possible contribution of end-user thesauri to the improvement of information retrieval by end- users. Thesauri (from the Greek for treasure or treasury) in information retrieval attempt to record and display relations among concepts and terms -- to be treasuries of concepts and the terms that represent them. End-user thesauri are designed to guide and facilitate end-user searching of textual databases (both full-text databases and reference databases that contain only surrogates of full-texts, such as abstracts). End-user thesauri link: the vocabulary of the searcher and the vocabulary of the database, functioning as part of the user database interface. End-user thesauri are not designed to guide indexing, although they can be used to suggest terms, much like writers have used Roget's thesaurus for centuries

    Building a Spiking Neural Network Model of the Basal Ganglia on SpiNNaker

    Get PDF
    We present a biologically-inspired and scalable model of the Basal Ganglia (BG) simulated on the SpiNNaker machine, a biologically-inspired low-power hardware platform allowing parallel, asynchronous computing. Our BG model consists of six cell populations, where the neuro-computational unit is a conductance-based Izhikevich spiking neuron; the number of neurons in each population is proportional to that reported in anatomical literature. This model is treated as a single-channel of action-selection in the BG, and is scaled-up to three channels with lateral cross-channel connections. When tested with two competing inputs, this three-channel model demonstrates action-selection behaviour. The SpiNNaker-based model is mapped exactly on to SpineML running on a conventional computer; both model responses show functional and qualitative similarity, thus validating the usability of SpiNNaker for simulating biologically-plausible networks. Furthermore, the SpiNNaker-based model simulates in real time for time-steps 1 ms; power dissipated during model execution is & #x2248;1.8 W

    Improving catalyst activity in secondary amine catalysed transformations

    Get PDF
    The effect on catalyst performance of altering substituents at the 2-position of the Macmillan imidazolidinone has been examined. Condensation of L-phenylalanine N-methyl amide with acetophenone derivatives results in a series of imidazolidinones whose salts can be used to accelerate the Diels-Alder cycloaddition. Electron withdrawing groups significantly increases the overall rate of cycloaddition without compromise in selectivity. The most effective catalyst was shown to be efficient for a variety of substrates and the applicability of this catalyst to alternative secondary amine catalysed transformations is also discussed

    What is a return to work after stroke?: 12 month work outcomes in a feasibility trial

    Get PDF
    Background: Return to work (RTW) is an outcome in determining the effectiveness of rehabilitation post-stroke. However, stroke survivors (SS) may return to different roles with altered work status. Income, hours, responsibilities and job-satisfaction may be reduced. SS may be dissatisfied if unable to resume apriori work status; alternatively adjusted work status may be viewed positively if perceived as a way of reducing the risk of another stroke. The purpose of this study was to explore what is meant by RTW. Method: Information about the nature of RTW (job type, hours, roles, responsibilities) was extracted from 3, 6 and 12 month follow-up postal questionnaires in 46 SS participants in a feasibility randomised controlled trial investigating effectiveness of a vocational rehabilitation intervention. Results/Findings: Participants took a mean 90 (SD:70, range 7-227) days to RTW. 19/46 reported working at 12 months. In 17 who supplied complete data, 7(41%) reported reduced working hours. Participants incurred a mean wage loss of 44% against pre-stroke earnings. 10/17(59%) participants were in the same job with the same employer and 6(35%) were working in different/modified jobs (1 missing:). 10/17(59%) had work-place adjustments. 18/46 (39%) participants were happy with their work situation. Discussion: Participants experienced marked changes in work status post-stroke, with implications for job-satisfaction, financial security and quality of life. Research into psychological adjustment following altered vocational status in SS is warranted. Conclusion: RTW is a complex outcome and may not translate to a return to pre-stroke vocational status. It is important to consider what constitutes a RTW following stroke

    Stakeholder Theory and Marketing: Moving from a Firm-Centric to a Societal Perspective

    Get PDF
    This essay is inspired by the ideas and research examined in the special section on “Stakeholder Marketing” of the Journal of Public Policy & Marketing in 2010. The authors argue that stakeholder marketing is slowly coalescing with the broader thinking that has occurred in the stakeholder management and ethics literature streams during the past quarter century. However, the predominant view of stakeholders that many marketers advocate is still primarily pragmatic and company centric. The position advanced herein is that stronger forms of stakeholder marketing that reflect more normative, macro/societal, and network-focused orientations are necessary. The authors briefly explain and justify these characteristics in the context of the growing “prosociety” and “proenvironment” perspectives—orientations that are also in keeping with the public policy focus of this journal. Under the “hard form” of stakeholder theory, which the authors endorse, marketing managers must realize that serving stakeholders sometimes requires sacrificing maximum profits to mitigate outcomes that would inflict major damage on other stakeholders, especially society

    Silicate weathering and carbon cycle controls on the Oligocene-Miocene transition glaciation

    Get PDF
    Changes in both silicate weathering rates and organic carbon burial have been proposed as drivers of the transient “Mi-1” glaciation event at the Oligocene-Miocene transition (OMT; ~23 Ma). However detailed geochemical proxy data are required to test these hypotheses. Here we present records of Li/Ca, Mg/Ca, Cd/Ca, U/Ca, δ18O, δ13C, and shell weight in planktonic foraminifera from marine sediments spanning the OMT in the equatorial Atlantic Ocean. Li/Ca values increase by 1 μmol/mol across this interval. We interpret this to indicate a ~20% increase in silicate weathering rates, which would have lowered atmospheric CO2, potentially forcing the Antarctic glaciation circa 23 Ma. δ13C of thermocline dwelling planktonic foraminifera track the global increase in seawater δ13C across the OMT and during the Mi-1 event, hence supporting a hypothesized global increase in organic carbon burial rates. High δ13C previously measured in epipelagic planktonic foraminifera and high Cd/Ca ratios during Mi-1 are interpreted to represent locally enhanced primary productivity, stimulated by increased nutrients supply to surface waters. The fingerprint of high export production and associated organic carbon burial at this site is found in reduced bottom water oxygenation (inferred from high foraminiferal U/Ca), and enhanced respiratory dissolution of carbonates, characterised by reduced foraminiferal shell weight. Replication of our results elsewhere would strengthen the case that weathering-induced CO2 sequestration preconditioned climate for Antarctic ice sheet growth across the OMT and increased burial of organic carbon acted as a feedback that intensified cooling at this time

    Molybdenum Disulphide Surfaces to Reduce Staphylococcus aureus and Pseudomonas aeruginosa Biofilm Formation.

    Get PDF
    The reduction of bacteria and biofilm formation is important when designing surfaces for use in industry. Molybdenum disulphide surfaces (MoS2SUR) were produced using MoS2 particle (MoS2PAR) sizes of 90 nm 2 µm and 6 µm containing MoS2PAR concentrations of 5%, 10%, 15% and 20%. These were tested to determine the efficacy of the MoS2SUR to impede bacterial retention and biofilm formation of two different types of bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. The MoS2SUR were characterised using Fourier Transform InfraRed Spectroscopy, Ion Coupled Plasma Atomic Emission Spectroscopy, Scanning Electron Microscopy, Optical Profilometry and Water Contact Angles. The MoS2SUR made with the smaller 90 nm MoS2PAR sizes demonstrated smaller topographical shaped features. As the size of the incorporated MoS2PAR increased, the MoS2SUR demonstrated wider surface features, and they were less wettable. The increase in MoS2PAR concentration within the MoS2SUR groups did not affect the surface topography but did increase wettability. However, the increase in MoS2PAR size increased both the surface topography and wettability. The MoS2SUR with the smaller topographical shaped features, influenced the retention of the S. aureus bacteria. Increased MoS2SUR topography and wettability resulted in the greatest reduction in bacterial retention and the bacteria became more heterogeneously dispersed and less clustered across the surfaces. The surfaces that exhibited decreased bacterial retention (largest particle sizes, largest features, greatest roughness, most wettable) resulted in decreased biofilm formation. Cytotoxicity testing of the surface using cell viability demonstrated that the MoS2SUR were not toxic against HK-2 cells at MoS2PAR sizes of 90 nm and 2 µm. This work demonstrated that individual surfaces variables (MoS2SUR topographic shape and roughness, MoS2PAR size and concentration) decreased bacterial loading on the surfaces, which then decreased biofilm formation. By optimising MoS2SUR properties, it was possible to impede bacterial retention and subsequent biofilm formation
    • …
    corecore