124 research outputs found

    The Information Theory of Vision: evidence from eye-movements

    Get PDF
    Recent evidence suggests that target-dissimilar items that are typically regarded as irrelevant to reaction times during visual search do, in fact, affect reaction times (Buetti et al., in revision). This evidence suggests that the effect on reaction time of target-dissimilar items (lures) increases logarithmically as the number of lures present in a display increases. In response to these findings, Buetti & Lleras (in preparation) developed a model of visual search, the Information Theory of Vision (ITV). ITV uniquely proposes that the time it takes to perform the initial stage of visual search, during which likely non-targets (lures) are separated from possible targets (candidates), will increase with the amount of information present in the display. ITV further employs Information Theory (Shannon, 1948), Signal Detection Theory (Green & Swets, 1966), and Hick’s Law (Hick, 1952) to support its predictions. In this study, we extend these predictions to eye-movements and find further support for ITV. Predictions of Guided Search (Wolfe, 1994) and Target Acqusition Model (Zelinsky, 2008) are also discussed

    The Proficiency Illusion

    Get PDF
    Examines the tests states use to measure academic progress under the No Child Left Behind Act. Explores whether expectations for proficiency in reading and mathematics are consistent between states

    Valuing EQ-5D health states: A review and analysis, CHERE Working Paper 2007/9

    Get PDF
    Objective: To identify the key methodological issues in the construction of population-level EQ-5D / Time Trade-Off (TTO) preference elicitation studies. Study Design: This study involves three components. The first was to identify existing population-level EQ-5D TTO studies. The second was to illustrate and discuss the key areas of divergence between studies, including the international comparison of tariffs. The third was to portray the relative merits of each of the approaches, and to compare the results of studies across countries. Results: While most papers report use of the protocol developed in the original UK study, we identified three key areas of divergence in the construction and analysis of surveys. These are the number of health states valued in order to determine the algorithm for estimating all health states, the approach to valuing states worse than immediate death, and the choice of algorithm. Finally, the evidence on international comparisons suggests differences between countries, although it is difficult to disentangle differences in cultural attitudes with random error and differences due to methodological divergence. Conclusion: Differences in methods are likely to obscure true differences in values between countries. However, population-specific valuation sets for countries engaging in economic evaluation would better represent societal attitudes.health state valuation, EQ5-D

    Visual working memory supports perceptual stability across saccadic eye movements

    Get PDF
    Vision is suppressed during saccadic eye movements. To create a stable perception of the visual world we must stitch together the gaps in visual input caused by this suppression. Early theories of perceptual stability proposed that information about the position of the eye could be used to cancel out changes in the retinal information resulting from a saccade. In contrast, more contemporary theories have proposed that perceptual stability relies on object correspondence across saccades, perhaps limited to the saccade target alone. According to these views, the visual system encodes features of the saccade target object into visual working memory (VWM) before a saccade is made. After the saccade, participants attempt to locate those features within a small region near the fovea. If this locating process succeeds, perceptual stability is maintained. The present study investigated directly whether perceptual stability does indeed rely on VWM. If it does, then perceived stability should be impaired when VWM is loaded with other visual information. Six experiments were conducted in which participants detected saccade target displacements while simultaneously maintaining a VWM or auditory working memory load (AWM). The VWM load negatively impacted participants’ ability to detect saccade target displacements and the saccade target displacement task negatively impacted memory for VWM task items. Neither of these effects were apparent when AWM was loaded. These results support the hypothesis that visual working memory supports perceptual stability across saccadic eye movements

    Rabies and the pandemic: lessons for One Health

    Get PDF
    This article examines the impact of coronavirus disease 2019 (COVID-19) on dog-mediated rabies, a neglected tropical disease that remains endemic in >65 countries. A globally agreed strategy for rabies elimination is underpinned by a One Health approach, coordinating human and animal health sectors and engaging communities. We present data on the scale and nature of COVID-19 disruption to rabies control programmes and the wider learning for One Health implementation. We argue that the global shift in health priorities caused by the pandemic, and consequent side-lining of animal health, will have broader ramifications for One Health implementation and preparedness for future emergent zoonoses

    Patterns of space use in sympatric marine colonial predators reveals scales of spatial partitioning

    Get PDF
    E.L.J. and D.J.F.R. were funded under Scottish Government grant MMSS001/01. D.J.F.R. was funded by the UK Department of Energy and Climate Change (DECC) as part of their Offshore Energy Strategic Environmental Assessment programme. S.S. was part-funded by the EU MYFISH project.Species distribution maps can provide important information to focus conservation efforts and enable spatial management of human activities. Two sympatric marine predators, grey seals Halichoerus grypus and harbour seals Phoca vitulina have overlapping ranges on land and at sea but contrasting population dynamics around Britain: whilst grey seals have generally increased, harbour seals have shown significant regional declines. We analysed two decades of at-sea movement data and terrestrial count data from these species to produce high resolution, broad-scale maps of distribution and associated uncertainty to inform conservation and management. Our results showed that grey seals use offshore areas connected to their haul-out sites by prominent corridors and harbour seals primarily stay within 50km of the coastline. Both species show fine-scale offshore spatial segregation off the east coast of Britain and broad-scale partitioning off western Scotland. These results illustrate that for broad-scale marine spatial planning, the conservation needs of harbour seals (primarily inshore, the exception being selected offshore usage areas) are different from those of grey seals (up to 100km offshore and corridors connecting these areas to haul-out sites). More generally, our results illustrate the importance of detailed knowledge of marine predator distributions to inform marine spatial planning; for instance, spatial prioritisation is not necessarily the most effective spatial planning strategy even when conserving species with similar taxonomy.Peer reviewe

    The CD100 Receptor Interacts with Its Plexin B2 Ligand to Regulate Epidermal γδ T Cell Function

    Get PDF
    Summaryγδ T cells respond rapidly to keratinocyte damage, providing essential contributions to the skin wound healing process. The molecular interactions regulating their response are unknown. Here, we identify a role for interaction of plexin B2 with the CD100 receptor in epithelial repair. In vitro blocking of plexin B2 or CD100 inhibited γδ T cell activation. Furthermore, CD100 deficiency in vivo resulted in delayed repair of cutaneous wounds due to a disrupted γδ T cell response to keratinocyte damage. Ligation of CD100 in γδ T cells induced cellular rounding via signals through ERK kinase and cofilin. Defects in this rounding process were evident in the absence of CD100-mediated signals, thereby providing a mechanistic explanation for the defective wound healing in CD100-deficient animals. The discovery of immune functions for plexin B2 and CD100 provides insight into the complex cell-cell interactions between epithelial resident γδ T cells and the neighboring cells they support

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

    Get PDF
    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
    corecore