4,171 research outputs found

    Destination images of non-visitors

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    This article provides much needed understanding of destination images held by non-visitors. Recognizing the characteristics of non-visitor images and their formation is important in order to understand images more widely. This qualitative study assesses images of London. The views of three hundred people in the Czech Republic who have never visited London were obtained via an innovative open-ended research instrument. The study showed that non-visitors imagine destinations through comparisons with their own experiences of places. Findings indicate that images can be very persistent and that the first images formed of a destination endure over time. Although the research is based on people with no direct experience of London, the research highlights that a range of secondary ‘experiences’ influence image formation

    On Kalmbach measurability

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    summary:In this note we show that, for an arbitrary orthomodular lattice LL, when Ό\mu is a faithful, finite-valued outer measure on LL, then the Kalmbach measurable elements of LL form a Boolean subalgebra of the centre of LL

    Process and reactor design for biophotolytic hydrogen production

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    The green alga Chlamydomonas reinhardtii has the ability to produce molecular hydrogen (H2), a clean and renewable fuel, through the biophotolysis of water under sulphur-deprived anaerobic conditions. The aim of this study was to advance the development of a practical and scalable biophotolytic H2 production process. Experiments were carried out using a purpose-built flat-plate photobioreactor, designed to facilitate green algal H2 production at the laboratory scale and equipped with a membrane-inlet mass spectrometry system to accurately measure H2 production rates in real time. The nutrient control method of sulphur deprivation was used to achieve spontaneous H2 production following algal growth. Sulphur dilution and sulphur feed techniques were used to extend algal lifetime in order to increase the duration of H2 production. The sulphur dilution technique proved effective at encouraging cyclic H 2 production, resulting in alternating Chlamydomonas reinhardtii recovery and H2 production stages. The sulphur feed technique enabled photobioreactor operation in chemostat mode, resulting in a small improvement in H2 production duration. A conceptual design for a large-scale photobioreactor was proposed based on these experimental results. This photobioreactor has the capacity to enable continuous and economical H 2 and biomass production using green algae. The success of these complementary approaches demonstrate that engineering advances can lead to improvements in the scalability and affordability of biophotolytic H2 production, giving increased confidence that H2 can fulfil its potential as a sustainable fuel of the future. © 2013 the Owner Societies

    Point-of-care measurement of blood lactate in children admitted with febrile illness to an African District Hospital.

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    BACKGROUND: Lactic acidosis is a consistent predictor of mortality owing to severe infectious disease, but its detection in low-income settings is limited to the clinical sign of "deep breathing" because of the lack of accessible technology for its measurement. We evaluated the use of a point-of-care (POC) diagnostic device for blood lactate measurement to assess the severity of illness in children admitted to a district hospital in Tanzania. METHODS: Children between the ages of 2 months and 13 years with a history of fever were enrolled in the study during a period of 1 year. A full clinical history and examination were undertaken, and blood was collected for culture, microscopy, complete blood cell count, and POC measurement of blood lactate and glucose. RESULTS: The study included 3248 children, of whom 164 (5.0%) died; 45 (27.4%) of these had raised levels of blood lactate (>5 mmol/L) but no deep breathing. Compared with mortality in children with lactate levels of ≀ 3 mmol/L, the unadjusted odds of dying were 1.6 (95% confidence interval [CI].8-3.0), 3.4 (95% CI, 1.5-7.5), and 8.9 (95% CI, 4.7-16.8) in children with blood lactate levels of 3.1-5.0, 5.1-8.0, or >8.0 mmol/L, respectively. The prevalence of raised lactate levels (>5 mmol/L) was greater in children with malaria than in children with nonmalarial febrile illness (P < .001) although the associated mortality was greater in slide-negative children. CONCLUSIONS: POC lactate measurement can contribute to the assessment of children admitted to hospital with febrile illness and can also create an opportunity for more hospitals in resource-poor settings to participate in clinical trials of interventions to reduce mortality associated with hyperlactatemia

    REPRESENTING ISOTONE OPERATORS ON CONES

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    Collisional decoherence observed in matter wave interferometry

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    We study the loss of spatial coherence in the extended wave function of fullerenes due to collisions with background gases. From the gradual suppression of quantum interference with increasing gas pressure we are able to support quantitatively both the predictions of decoherence theory and our picture of the interaction process. We thus explore the practical limits of matter wave interferometry at finite gas pressures and estimate the required experimental vacuum conditions for interferometry with even larger objects.Comment: 4 pages, 3 figure

    Theory of decoherence in a matter wave Talbot-Lau interferometer

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    We present a theoretical framework to describe the effects of decoherence on matter waves in Talbot-Lau interferometry. Using a Wigner description of the stationary beam the loss of interference contrast can be calculated in closed form. The formulation includes both the decohering coupling to the environment and the coherent interaction with the grating walls. It facilitates the quantitative distinction of genuine quantum interference from the expectations of classical mechanics. We provide realistic microscopic descriptions of the experimentally relevant interactions in terms of the bulk properties of the particles and show that the treatment is equivalent to solving the corresponding master equation in paraxial approximation.Comment: 20 pages, 4 figures (minor corrections; now in two-column format

    Towards reviving post-Olympic Athens as a cultural destination

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    This paper examines the effects of global change on the status and qualities of the Greek national capital, Athens, focusing on how they affect the development of cultural tourism in the city. Although Athens constituted one of the most significant destinations for Greek tourism in the past, in recent years it started to weaken. Athens is characterised by a series of problems, among them are the degradation of its environment and quality of life and traffic congestion. However, in terms of tourism development, the Olympic Games helped in re-imaging the city and upgrading its infrastructure. This study based on semi-structured interviews with top officials reveals how global change has affected Athens’ socio-cultural/economic status, identity and image. Despite the tourism policy/planning responses to global changes, Athens’ tourism continues to decline leaving unexplored potential such as its rich cultural heritage, new multicultural identity and the New Acropolis Museum. The paper suggests that cultural elements of capital cities must be multidimensional including a variety of attractions and amenities. The use of cultural heritage assets needs to be in line with global developments in order for cities to effectively leverage heritage for cultural tourism
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