3,398 research outputs found

    Effects of moisture in infrared thermography of resin matrix composites

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    Several multiply graphite polyimide composite specimens were examined by real-time infrared thermography in order to study the effects of moisture on their thermograms. Heat was injected from one side and IR emission detected on the opposite side using AGA Thermovision System-680. No differences between the thermograms of dry and water containing specimens were detected for defect-free specimens. However, the presence of trapped water in defective specimens modified the thermographic contrast significantly. It is concluded that: (1) IR thermography can be used to detect moisture in defective composites, and (2) because of the possibility of moisture camouflaging defects, IR thermography for subsurface defect detection should be supplemented by other techniques - such as acoustical imaging and X-radiography

    Cues and knowledge structures used by mental-health professionals when making risk assessments

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    Background: Research into mental-health risks has tended to focus on epidemiological approaches and to consider pieces of evidence in isolation. Less is known about the particular factors and their patterns of occurrence that influence clinicians’ risk judgements in practice. Aims: To identify the cues used by clinicians to make risk judgements and to explore how these combine within clinicians’ psychological representations of suicide, self-harm, self-neglect, and harm to others. Method: Content analysis was applied to semi-structured interviews conducted with 46 practitioners from various mental-health disciplines, using mind maps to represent the hierarchical relationships of data and concepts. Results: Strong consensus between experts meant their knowledge could be integrated into a single hierarchical structure for each risk. This revealed contrasting emphases between data and concepts underpinning risks, including: reflection and forethought for suicide; motivation for self-harm; situation and context for harm to others; and current presentation for self-neglect. Conclusions: Analysis of experts’ risk-assessment knowledge identified influential cues and their relationships to risks. It can inform development of valid risk-screening decision support systems that combine actuarial evidence with clinical expertise

    Using XML and XSLT for flexible elicitation of mental-health risk knowledge

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    Current tools for assessing risks associated with mental-health problems require assessors to make high-level judgements based on clinical experience. This paper describes how new technologies can enhance qualitative research methods to identify lower-level cues underlying these judgements, which can be collected by people without a specialist mental-health background. Methods and evolving results: Content analysis of interviews with 46 multidisciplinary mental-health experts exposed the cues and their interrelationships, which were represented by a mind map using software that stores maps as XML. All 46 mind maps were integrated into a single XML knowledge structure and analysed by a Lisp program to generate quantitative information about the numbers of experts associated with each part of it. The knowledge was refined by the experts, using software developed in Flash to record their collective views within the XML itself. These views specified how the XML should be transformed by XSLT, a technology for rendering XML, which resulted in a validated hierarchical knowledge structure associating patient cues with risks. Conclusions: Changing knowledge elicitation requirements were accommodated by flexible transformations of XML data using XSLT, which also facilitated generation of multiple data-gathering tools suiting different assessment circumstances and levels of mental-health knowledge

    Quantum Vacuum Contribution to the Momentum of the Dielectric Media

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    Momentum transfer between matter and electromagnetic field is analyzed. The related equations of motion and conservation laws are derived using relativistic formalism. Their correspondence to various, at first sight self-contradicting, experimental data (the so called Abraham-Minkowski controversy) is demonstrated. A new, Casimir like, quantum phenomenon is predicted: contribution of vacuum fluctuations to the motion of dielectric liquids in crossed electric and magnetic fields. Velocities about 50nm/s50nm/s can be expected due to the contribution of high frequency vacuum modes

    Scaffolding School Pupils’ Scientific Argumentation with Evidence-Based Dialogue Maps

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    This chapter reports pilot work investigating the potential of Evidence-based Dialogue Mapping to scaffold young teenagers’ scientific argumentation. Our research objective is to better understand pupils’ usage of dialogue maps created in Compendium to write scientific ex-planations. The participants were 20 pupils, 12-13 years old, in a summer science course for “gifted and talented” children in the UK. Through qualitative analysis of three case studies, we investigate the value of dialogue mapping as a mediating tool in the scientific reasoning process during a set of learning activities. These activities were published in an online learning envi-ronment to foster collaborative learning. Pupils mapped their discussions in pairs, shared maps via the online forum and in plenary discussions, and wrote essays based on their dialogue maps. This study draws on these multiple data sources: pupils’ maps in Compendium, writings in science and reflective comments about the uses of mapping for writing. Our analysis highlights the diversity of ways, both successful and unsuccessful, in which dialogue mapping was used by these young teenagers

    Late-time oscillatory behaviour for self-gravitating scalar fields

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    This paper investigates the late-time behaviour of certain cosmological models where oscillations play an essential role. Rigorous results are proved on the asymptotics of homogeneous and isotropic spacetimes with a linear massive scalar field as source. Various generalizations are obtained for nonlinear massive scalar fields, kk-essence models and f(R)f(R) gravity. The effect of adding ordinary matter is discussed as is the case of nonlinear scalar fields whose potential has a degenerate zero.Comment: 17 pages, additional reference

    Evolving Spatially Aggregated Features from Satellite Imagery for Regional Modeling

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    Satellite imagery and remote sensing provide explanatory variables at relatively high resolutions for modeling geospatial phenomena, yet regional summaries are often desirable for analysis and actionable insight. In this paper, we propose a novel method of inducing spatial aggregations as a component of the machine learning process, yielding regional model features whose construction is driven by model prediction performance rather than prior assumptions. Our results demonstrate that Genetic Programming is particularly well suited to this type of feature construction because it can automatically synthesize appropriate aggregations, as well as better incorporate them into predictive models compared to other regression methods we tested. In our experiments we consider a specific problem instance and real-world dataset relevant to predicting snow properties in high-mountain Asia

    What do people do with porn? qualitative research into the consumption, use and experience of pornography and other sexually explicit media

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    This article reviews qualitative research into the consumption of pornography and other sexually explicit media emerging from a range of subject areas. Taking a critique of quantitative methods and a focus on measuring sexual effects and attitudes as a starting point, it considers the proposition that qualitative work is more suited to an examination of the complex social, cultural and political constructions of sexuality. Examining studies into the way men, women and young people see, experience, and use explicit media texts, the article identifies the key findings that have emerged. Qualitative work shows that sexuality explicit media texts are experienced and understood in a variety of ways and evoke strong and often contradictory reactions, not all of which are represented in public debates about pornography. These texts function in a range of different ways, depending on context; as a source of knowledge, a resource for intimate practices, a site for identity construction, and an occasion for performing gender and sexuality. The article reviews these studies and their findings, identifying what they suggest about directions for future research, both in terms of developing methodology and refining approaches to sexuality and media consumption.</p

    Tracking the reflexivity of the (dis)engaged citizen: some methodological reflections

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    The relationship between governments and citizens in many contemporary democracies is haunted by uncertainty and sociologists face the task of listening effectively to citizens’ own reflections on this uncertain relationship. This article reflects on the qualitative methodology of a recently completed UK project which used a combination of diary and multiple interviews/ focus groups to track over a fieldwork period of up to a year citizens’ reflections on their relationship to a public world and the contribution to this of their media consumption. In particular, the article considers how the project’s multiple methods enabled multiple angles on the inevitable artificiality and performative dimension of the diary process, resulting in rich data on people’s complex reflections on the uncertain position of the contemporary citizen
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