77 research outputs found

    The ship recycling conundrum: an econometric analysis of market dynamics and industry trends

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    Ship recycling has received considerable attention during the last two decades for a variety of reasons and the industry is currently under a thorough scrutiny with the likelihood of the adoption of a new multilateral convention under the auspices of the International Maritime Organization (IMO). This study applies econometric modeling to a unique dataset to provide a holistic insight into the dynamics of the ship recycling market. The dataset contains information on 51,112 ships over 100 gt and includes 748,621 events over a period of 29 years. The binary logistic regression models used provide insights for a shipping-related sector that has received scant scholarly attention in the past. It is expected that these contributions will provide empirical support for the ongoing IMO discussions in this important field.

    Age-related changes in global motion coherence: conflicting haemodynamic and perceptual responses

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    Our aim was to use both behavioural and neuroimaging data to identify indicators of perceptual decline in motion processing. We employed a global motion coherence task and functional Near Infrared Spectroscopy (fNIRS). Healthy adults (n = 72, 18-85) were recruited into the following groups: young (n = 28, mean age = 28), middle-aged (n = 22, mean age = 50), and older adults (n = 23, mean age = 70). Participants were assessed on their motion coherence thresholds at 3 different speeds using a psychophysical design. As expected, we report age group differences in motion processing as demonstrated by higher motion coherence thresholds in older adults. Crucially, we add correlational data showing that global motion perception declines linearly as a function of age. The associated fNIRS recordings provide a clear physiological correlate of global motion perception. The crux of this study lies in the robust linear correlation between age and haemodynamic response for both measures of oxygenation. We hypothesise that there is an increase in neural recruitment, necessitating an increase in metabolic need and blood flow, which presents as a higher oxygenated haemoglobin response. We report age-related changes in motion perception with poorer behavioural performance (high motion coherence thresholds) associated with an increased haemodynamic response

    Reversal of stress fibre formation by Nitric Oxide mediated RhoA inhibition leads to reduction in the height of preformed thrombi

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    Evidence has emerged to suggest that thrombi are dynamic structures with distinct areas of differing platelet activation and inhibition. We hypothesised that Nitric oxide (NO), a platelet inhibitor, can modulate the actin cytoskeleton reversing platelet spreading, and therefore reduce the capability of thrombi to withstand a high shear environment. Our data demonstrates that GSNO, DEANONOate, and a PKG-activating cGMP analogue reversed stress fibre formation and increased actin nodule formation in adherent platelets. This effect is sGC dependent and independent of ADP and thromboxanes. Stress fibre formation is a RhoA dependent process and NO induced RhoA inhibition, however, it did not phosphorylate RhoA at ser188 in spread platelets. Interestingly NO and PGI2 synergise to reverse stress fibre formation at physiologically relevant concentrations. Analysis of high shear conditions indicated that platelets activated on fibrinogen, induced stress fibre formation, which was reversed by GSNO treatment. Furthermore, preformed thrombi on collagen post perfused with GSNO had a 30% reduction in thrombus height in comparison to the control. This study demonstrates that NO can reverse key platelet functions after their initial activation and identifies a novel mechanism for controlling excessive thrombosis

    Structural and functional evolution of the P2Y12-like receptor group

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    Metabotropic pyrimidine and purine nucleotide receptors (P2Y receptors) belong to the superfamily of G protein-coupled receptors (GPCR). They are distinguishable from adenosine receptors (P1) as they bind adenine and/or uracil nucleotide triphosphates or diphosphates depending on the subtype. Over the past decade, P2Y receptors have been cloned from a variety of tissues and species, and as many as eight functional subtypes have been characterized. Most recently, several members of the P2Y12-like receptor group, which includes the clopidogrel-sensitive ADP receptor P2Y12, have been deorphanized. The P2Y12-like receptor group comprises several structurally related GPCR which, however, display heterogeneous agonist specificity including nucleotides, their derivatives, and lipids. Besides the established function of P2Y12 in platelet activation, expression in macrophages, neuronal and glial cells as well as recent results from functional studies implicate that several members of this group may have specific functions in neurotransmission, inflammation, chemotaxis, and response to tissue injury. This review focuses specifically on the structure-function relation and shortly summarizes some aspects of the physiological relevance of P2Y12-like receptor members

    Research skills for software engineering undergraduates in dutch universities of applied sciences

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    Undergraduate students who seek a bachelor degree in Dutch universities of applied sciences are supposed to learn also research skills so that they can provide innovative solutions to real problems of the society and businesses in their future careers. Current education and textbooks on research skills are not tuned well to software engineering disciplines. This paper describes our vision about the scope and model of the research suitable for software engineering disciplines in Dutch universities of applied sciences. Based on literature study we identify a number of research models that are commonly used in computer science. Through reviewing a number of graduation reports in our university, we further identify which of the research models are most suitable for the (graduation) projects of software engineering disciplines and also investigate their shortcomings with respect to the desired research skills. Our study reveals that the approach of most graduation works is close to the implementation-based (also called build-based or proof by example based) research model. In order to be considered as a realization of sound applied research, however, most of theses graduation works need to be improved on a number of aspects such as problem context definition, system/prototype evaluation, and critical literature study

    [Visceral leishmaniasis: not only a tropical disease].

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    Item does not contain fulltextWe report 2 cases of visceral leishmaniasis in Dutch patients after a stay in Greece and the former Yugoslavia, respectively. Patient A, a 69-year-old woman, was referred to our department with abdominal pain. Additional examinations were suggestive of chronic liver disease. After a liver biopsy, which demonstrated hepatic granulomas, we admitted the patient due to a sudden onset of cyclic fever. Patient B, a 50-year-old woman, was admitted with cyclic fever and abdominal pain. We treated the patient with IV antibiotics and discontinued the methotrexate treatment for her rheumatoid arthritis. Both patients were diagnosed with visceral leishmaniasis and treated with liposomal amphotericin-B. Patient A, an immunocompetent patient, had stayed in Greece for prolonged periods. Patient B had lived in the former Yugoslavia until 1999, and her methotrexate use had likely activated an asymptomatic Leishmania infection. Visceral leishmaniasis, a potentially lethal protozoan disease, should be considered in patients who have travelled in Southern Europe
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