1,145 research outputs found

    Modern seawater acidification: The response of foraminifera to high-CO<inf>2</inf> conditions in the Mediterranean Sea

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    The seas around the island of Ischia (Italy) have a lowered pH as a result of volcanic gas vents that emit carbon dioxide from the sea floor at ambient seawater temperatures. These areas of acidified seawater provide natural laboratories in which to study the long-term biological response to rising CO2 levels. Benthic foraminifera (single-celled protists) are particularly interesting as they have short life histories, are environmentally sensitive and have an excellent fossil record. Here, we examine changes in foraminiferal assemblages along pH gradients at CO2 vents on the coast of Ischia and show that the foraminiferal distribution, diversity and nature of the fauna change markedly in the living assemblages as pH decreases. © 2010 Geological Society of London

    Spaces for smoking in a psychiatric hospital: social capital, resistance to control, and significance for 'therapeutic landscapes'

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    This paper reports on research framed by theories of therapeutic landscapes and the ways that the social, physical and symbolic dimensions of landscapes relate to wellbeing and healing. We focus especially on the question of how attributes of therapeutic landscapes are constructed in different ways according to the variable perspectives of individuals and groups. Through an ethnographic case study in a psychiatric hospital in the North of England we explore the perceived significance for wellbeing of ‘smoking spaces’ (where tobacco smoking is practiced in ways that may, or may not be officially sanctioned). We interpret our findings in light of literature on how smoking spaces are linked to the socio-geographical power relations that determine how smoking is organised within the hospital and how this is understood by different groups using the hospital building. We draw on qualitative research findings from discussion groups, observations, and interviews with patients, carers and staff. These focused on their views about the building design and setting of the new psychiatric hospital in relation to their wellbeing, and issues relating to smoking spaces emerged as important for many participants. Creating and managing smoking spaces as a public health measure in psychiatric hospitals is shown to be a controversial issue involving conflicting aims for health and wellbeing of patients and staff. Our findings indicate that although from a physical health perspective, smoking is detrimental, the spaces in which patients and staff smoke have social and psychological significance, providing a forum for the creation of social capital and resistance to institutional control. While the findings relate to one case study setting, the paper illustrates issues of wider relevance and contributes to an international literature concerning the tensions between perceived psychological and psychosocial benefits of smoking vs. physical harm that smoking is likely to cause. We consider the implications for hospital design and the model of care

    Machine learning classification of OARSI-scored human articular cartilage using magnetic resonance imaging

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    SummaryObjectiveThe purpose of this study is to evaluate the ability of machine learning to discriminate between magnetic resonance images (MRI) of normal and pathological human articular cartilage obtained under standard clinical conditions.MethodAn approach to MRI classification of cartilage degradation is proposed using pattern recognition and multivariable regression in which image features from MRIs of histologically scored human articular cartilage plugs were computed using weighted neighbor distance using compound hierarchy of algorithms representing morphology (WND-CHRM). The WND-CHRM method was first applied to several clinically available MRI scan types to perform binary classification of normal and osteoarthritic osteochondral plugs based on the Osteoarthritis Research Society International (OARSI) histological system. In addition, the image features computed from WND-CHRM were used to develop a multiple linear least-squares regression model for classification and prediction of an OARSI score for each cartilage plug.ResultsThe binary classification of normal and osteoarthritic plugs yielded results of limited quality with accuracies between 36% and 70%. However, multiple linear least-squares regression successfully predicted OARSI scores and classified plugs with accuracies as high as 86%. The present results improve upon the previously-reported accuracy of classification using average MRI signal intensities and parameter values.ConclusionMRI features detected by WND-CHRM reflect cartilage degradation status as assessed by OARSI histologic grading. WND-CHRM is therefore of potential use in the clinical detection and grading of osteoarthritis

    Come back Marshall, all is forgiven? : Complexity, evolution, mathematics and Marshallian exceptionalism

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    Marshall was the great synthesiser of neoclassical economics. Yet with his qualified assumption of self-interest, his emphasis on variation in economic evolution and his cautious attitude to the use of mathematics, Marshall differs fundamentally from other leading neoclassical contemporaries. Metaphors inspire more specific analogies and ontological assumptions, and Marshall used the guiding metaphor of Spencerian evolution. But unfortunately, the further development of a Marshallian evolutionary approach was undermined in part by theoretical problems within Spencer's theory. Yet some things can be salvaged from the Marshallian evolutionary vision. They may even be placed in a more viable Darwinian framework.Peer reviewedFinal Accepted Versio

    Thickness Estimation of Epitaxial Graphene on SiC using Attenuation of Substrate Raman Intensity

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    A simple, non-invasive method using Raman spectroscopy for the estimation of the thickness of graphene layers grown epitaxially on silicon carbide (SiC) is presented, enabling simultaneous determination of thickness, grain size and disorder using the spectra. The attenuation of the substrate Raman signal due to the graphene overlayer is found to be dependent on the graphene film thickness deduced from X-ray photoelectron spectroscopy and transmission electron microscopy of the surfaces. We explain this dependence using an absorbing overlayer model. This method can be used for mapping graphene thickness over a region and is capable of estimating thickness of multilayer graphene films beyond that possible by XPS and Auger electron spectroscopy (AES).Comment: 14 pages, 9 figure

    Theoretical overview on high-energy emission in microquasars

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    Microquasar (MQ) jets are sites of particle acceleration and synchrotron emission. Such synchrotron radiation has been detected coming from jet regions of different spatial scales, which for the instruments at work nowadays appear as compact radio cores, slightly resolved radio jets, or (very) extended structures. Because of the presence of relativistic particles and dense photon, magnetic and matter fields, these outflows are also the best candidates to generate the very high-energy (VHE) gamma-rays detected coming from two of these objects, LS 5039 and LS I +61 303, and may be contributing significantly to the X-rays emitted from the MQ core. In addition, beside electromagnetic radiation, jets at different scales are producing some amount of leptonic and hadronic cosmic rays (CR), and evidences of neutrino production in these objects may be eventually found. In this work, we review on the different physical processes that may be at work in or related to MQ jets. The jet regions capable to produce significant amounts of emission at different wavelengths have been reduced to the jet base, the jet at scales of the order of the size of the system orbital semi-major axis, the jet middle scales (the resolved radio jets), and the jet termination point. The surroundings of the jet could be sites of multiwavelegnth emission as well, deserving also an insight. We focus on those scenarios, either hadronic or leptonic, in which it seems more plausible to generate both photons from radio to VHE and high-energy neutrinos. We briefly comment as well on the relevance of MQ as possible contributors to the galactic CR in the GeV-PeV range.Comment: Astrophysics & Space Science, in press (invited talk in the conference: The multimessenger approach to the high-energy gamma-ray sources", Barcelona/Catalonia, in July 4-7); 10 pages, 6 figures, 2 tables (one reference corrected
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