597 research outputs found

    Searching for Serendipitous Analogies

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    Analogical reasoning is an acknowledged process behind many episodes of creativity. Typically, the creator chances upon information unrelated to the given problem – and solves the problem by analogy with this accidental source of inspiration. Current models of analogical retrieval do not explain how semantically unrelated source domains are retrieved. We present the RADAR algorithm that maps domains into a separate structure space, where domains with similar topological attributes are colocated. Each axis in structure space records the occurrence frequency of that feature in each domain. Nearest neighbour retrieval in structure space identifies structurally similar domains - from a diversity of semantic backgrounds. Structure based retrieval opens the possibility for creating an analogy model with far greater creativity potential than human reasoning

    Features of Structure for Anaology Retrieval

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    Spontaneously retrieving analogies from presented problem data is an important phase of analogical reasoning, influencing many related cognitive processes. Existing models have focused on semantic similarity, but structural similarity is also a necessary requirement of any analogical comparison. We present a new technique for performing structure based analogy retrieval. This is founded upon derived attributes that explicitly encode elementary structural qualities of a domains representation. Crucially, these attributes are unrelated to the semantic content of the domain information, and encode only its structural qualities. We describe a number of derived attributes and detail the computation of the corresponding attribute values. We examine our models operation, detailing how it retrieves both semantically related and unrelated domains. We also present a comparison of our algorithms performance with existing models, using a structure rich but semantically impoverished domai

    Oral health and pathology: a macrophage account.

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    Macrophages are present in healthy oral mucosa and their numbers increase dramatically during disease. They can exhibit a diverse range of phenotypes characterised as a functional spectrum from pro-inflammatory to anti-inflammatory (regulatory) subsets. This review illustrates the role of these subsets in the oral inflammatory disease lichen planus, and the immunosuppressive disease oral squamous cell carcinoma (SCC). We conclude that the role of macrophages in driving progression in oral disease identifies them as potential therapeutic targets for a range of oral pathologies

    Restenosis and its determinants in first and repeat coronary angioplasty

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    Restenosis is the main problem limiting long-term success of percutaneous transluminal coronary angioplasty (PTCA) and is most accurately evaluated by follow-up angiography. We compared the primary and long-term results of angioplasty in 268 consecutive patients (293 segments) with first PTCA (PTCA 1, angiographic follow-up 98%) and in 66 patients (76 segments) with repeat PTCA after restenosis (PTCA 2, angiographic follow-up 92%). Forty clinical, angiographic and procedural factors were assessed in relation to outcome. Primary success rate was higher in PTCA 2 (91% vs 67.5%) and major complications were fewer (4.5% vs 16%).Higher inflation pressure (7.9 ± 2.3 vs 6.8 ± 1.8 atm, P70%) after PTCA 1 and after PTC A 2 (27% vs 36%, P = NS) and the mean time to recurrence (4.7 vs 5.3 months, P = NS) were similar. Procedural factors were the main determinants of long-term success in primary PTCA. The restenosis risk was independently related to residual stenosis >45% (P<0.001), variant angina (P<0.05) and multivessel disease (P<0.05) after PTCA 1 and to male sex (P<0.001) and higher inflation pressure (P<0.05) after PTCA 2. Mild to moderate intimal tearing was associated with less restenosis after PTC A 1, but not after PTCA 2. Including 9 patients (10 segments) with a third PTCA, 70% of the 66 patients with repeat PTCA had a successful long-term outcome. Repeat angioplasty should therefore be considered as an integral part of PTCA therapy. Restenosis however remains a major concern. An optimal primary result with a minimal residual stenosis is decisive for first PTCA, whereas avoidance of a dissection by using lower inflation pressure on a restenosis might improve the long-term outcome of repeat PTC

    STORMTOOLS: Coastal Environmental Risk Index (CERI)

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    One of the challenges facing coastal zone managers and municipal planners is the development of an objective, quantitative assessment of the risk to structures, infrastructure, and public safety that coastal communities face from storm surge in the presence of changing climatic conditions, particularly sea level rise and coastal erosion. Here we use state of the art modeling tool (ADCIRC and STWAVE) to predict storm surge and wave, combined with shoreline change maps (erosion), and damage functions to construct a Coastal Environmental Risk Index (CERI). Access to the state emergency data base (E-911) provides information on structure characteristics and the ability to perform analyses for individual structures. CERI has been designed as an on line Geographic Information System (GIS) based tool, and hence is fully compatible with current flooding maps, including those from FEMA. The basic framework and associated GIS methods can be readily applied to any coastal area. The approach can be used by local and state planners to objectively evaluate different policy options for effectiveness and cost/benefit. In this study, CERI is applied to RI two communities; Charlestown representing a typical coastal barrier system directly exposed to ocean waves and high erosion rates, with predominantly low density single family residences and Warwick located within Narragansett Bay, with more limited wave exposure, lower erosion rates, and higher residential housing density. Results of these applications are highlighted herein
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