9 research outputs found

    Implantation of multiply charged carbon ions in water ice

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    Context. Several objects in the Solar System like Europa, Ganymede and Callisto have frozen surface (main component: H2O). The associated thickness is bigger than the penetration depth of the relevant projectile ions. Additionally, other species such as H2O2, SO2 and CO2 have been detected on these surface. The formation mechanisms of these molecules are still under discussion. Aims. We present new experimental results on the implantation of 13Cq+ (q = 2, 3) ions at an energy of 30 keV in water ice at low temperatures (15 and 80 K). Experiments with multiply charged ions at energies of tens of keV are particularly relevant to simulating the complexity of the irradiation environment to which the surfaces of the icy moons in the outer solar system are exposed. Methods. The experiments were performed at the low energy ion beam facility ARIBE of GANIL in Caen (France). 30 keV 13Cq+ (q = 2, 3) ions have been used to bombard solid H,2O surface which were frozen at 15K and 80K. Fourier Transform Infrared Spectrometer (FTIR) was used to analyze the sample in the 5000 - 600 cm-1 (2-16.7 μm) region with a spectral resolution of 1 cm-1. Results. The results of our experiments indicate that implantation produces 13CO2 with yields in the range of 0.32-0.57 molecules ion-1. This yield seems to be independent of the temperature of the ices in the range studied. We have estimated the time scale necessary to accumulate by implantation of magnetospheric carbon ions the observed quantity of carbon dioxide on the surface of Europa, a Jovian moon. This time scale is of the order of 1.0-1.3x104 yrs which is higher than that evaluated for carbon dioxide production by other relevant processes. Conclusions.We conclude that although a relevant quantity of CO2 can be formed by carbon ion implantation, this is not the dominant formation mechanism at Europa

    Photographing Absence in Deathscapes

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    How do visual methods, particularly the practice of photography, help us to visualise and understand absence in deathscapes? In this paper I will argue that photographs, with their ability to freeze moments, are able to capture what I term points of praxis – moments in which practices by individuals inscribe meaning onto deathscapes, and in that intense and captured presence, evoke the feeling of absent individuals. Such points of praxis can exist in two ways – the praxis of the body and the praxis of objects – both of which I will illuminate with the use of visual ethnographic methods. To support my argument, I present work taken from a three‐year visual ethnographic study of Bukit Brown Cemetery, specifically drawing on the social and cultural documentation of the Hungry Ghost Festival

    Running away with health: the urban marathon and the construction of charitable bodies

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    The increase in fundraising through mass-participation running events is emblematic of a series of issues pertinent to contemporary conceptualizations of health and illness. This increasingly popular spectacle serves as an indicator of present-day social relationships and broader cultural and ideological values that pertain to health. It highlights contemporary discourses on citizenship; ‘active citizens’ can ostentatiously fulfil their rights and responsibilities by raising money for those ‘in need’. Involvement in such events comprises an example of the current trend for drawing attention to illness, and sharing one’s experiences with others. We examine these issues through a consideration of charity advertisements and offer a fourfold typology of runners in terms of their orientations to both mass-participation running and charity. We conclude that ‘charitable bodies’ are constructed out of the interrelationships between philanthropic institutions, sport and individual performance

    National Preclinical Sepsis Platform: developing a framework for accelerating innovation in Canadian sepsis research

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    Abstract Despite decades of preclinical research, no experimentally derived therapies for sepsis have been successfully adopted into routine clinical practice. Factors that contribute to this crisis of translation include poor representation by preclinical models of the complex human condition of sepsis, bias in preclinical studies, as well as limitations of single-laboratory methodology. To overcome some of these shortcomings, multicentre preclinical studies—defined as a research experiment conducted in two or more research laboratories with a common protocol and analysis—are expected to maximize transparency, improve reproducibility, and enhance generalizability. The ultimate objective is to increase the efficiency and efficacy of bench-to-bedside translation for preclinical sepsis research and improve outcomes for patients with life-threatening infection. To this end, we organized the first meeting of the National Preclinical Sepsis Platform (NPSP). This multicentre preclinical  research collaboration of Canadian sepsis researchers and stakeholders was established to study the pathophysiology of sepsis and accelerate movement of promising therapeutics into early phase clinical trials. Integrated knowledge translation and shared decision-making were emphasized to ensure the goals of the platform align with clinical researchers and patient partners. 29 participants from 10 independent labs attended and discussed four main topics: (1) objectives of the platform; (2) animal models of sepsis; (3) multicentre methodology and (4) outcomes for evaluation. A PIRO model (predisposition, insult, response, organ dysfunction) for experimental design was proposed to strengthen linkages with interdisciplinary researchers and key stakeholders. This platform represents an important resource for maximizing translational impact of preclinical sepsis research
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