8,419 research outputs found

    NMR and Rheological Study of Anion Size Influence on the Properties of Two Imidazolium-based Ionic Liquids

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    NMR self-diffusion and relaxation, coupled with viscosity, were used to study the properties and structure of two imidazolium-based ionic liquids, 1-ethyl-3-methylimidazolium acetate [C2MIM][OAc] and 1-ethyl-3-methylimidazolium octanoate [C2MIM][OOct]. The experimental results point to the formation of different types of aggregates in each ionic liquid. These aggregates are small and stable under flow and temperature in [C2MIM][OAc], whereas the aggregates are large and sensitive to flow and temperature in [C2MIM][OOct]. In the latter case the size of aggregates decreases both under flow and temperature increase

    Opioid-sparing effects of perioperative paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) in children.

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    Perioperative pain in children can be effectively managed with systemic opioids, but addition of paracetamol or nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce opioid requirements and potentially improve analgesia and/or reduce adverse effects

    Limitations for change detection in multiple Gabor targets

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    We investigate the limitations on the ability to detect when a target has changed, using Gabor targets as simple quantifiable stimuli. Using a partial report technique to equalise response variables, we show that the log of the Weber fraction for detecting a spatial frequency change is proportional to the log of the number of targets, with a set-size effect that is greater than that reported for visual search. This is not a simple perceptual limitation, because pre-cueing a single target out of four restores performance to the level found when only one target is present. It is argued that the primary limitation on performance is the division of attention across multiple targets, rather than decay within visual memory. However in a simplified change detection experiment without cueing, where only one target of the set changed, not only was the set size effect still larger, but it was greater at 2000 msec ISI than at 250 msec ISI, indicating a possible memory component. The steepness of the set size effects obtained suggests that even moderate complexity of a stimulus in terms of number of component objects can overload attentional processes, suggesting a possible low-level mechanism for change blindness

    Evidence for ecosystem state shifts in Alaskan continuous permafrost peatlands in response to recent warming

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    Peatlands in continuous permafrost regions represent a globally-important store of organic carbon, the stability of which is thought to be at risk under future climatic warming. To better understand how these ecosystems may change in a warmer future, we use a palaeoenvironmental approach to reconstruct changes in two peatlands near Toolik Lake on Alaska's North Slope (TFS1 and TFS2). We present the first testate amoeba-based reconstructions from peatlands in continuous permafrost, which we use to infer changes in water-table depth and porewater electrical conductivity during the past two millennia. TFS1 likely initiated during a warm period between 0 and 300 CE. Throughout the late-Holocene, both peatlands were minerotrophic fens with low carbon accumulation rates (means of 18.4 and 14.2 g C m−2 yr−1 for cores TFS1 and TFS2 respectively). However, since the end of the Little Ice Age, both fens have undergone a rapid transition towards oligotrophic peatlands, with deeper water tables and increased carbon accumulation rates (means of 59.5 and 48.2 g C m−2 yr−1 for TFS1 and TFS2 respectively). We identify that recent warming has led to these two Alaskan rich fens to transition into poor fens, with greatly enhanced carbon accumulation rates. Our work demonstrates that some Arctic peatlands may become more productive with future regional warming, subsequently increasing their ability to sequester carbon

    Using 'snapshot' measurements of CH4 fluxes from an ombrotrophic peatland to estimate annual budgets: interpolation versus modelling

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    Flux-chamber measurements of greenhouse gas exchanges between the soil and the atmosphere represent a snapshot of the conditions on a particular site and need to be combined or used in some way to provide integrated fluxes for the longer time periods that are often of interest. In contrast to carbon dioxide (CO₂), most studies that have estimated the time-integrated flux of CH₄ on ombrotrophic peatlands have not used models. Typically, linear interpolation is used to estimate CH₄ fluxes during the time periods between flux-chamber measurements. CH₄ fluxes generally show a rise followed by a fall through the growing season that may be captured reasonably well by interpolation, provided there are sufficiently frequent measurements. However, day-to-day and week-to-week variability is also often evident in CH₄ flux data, and will not necessarily be properly represented by interpolation. Using flux chamber data from a UK blanket peatland, we compared annualised CH₄ fluxes estimated by interpolation with those estimated using linear models and found that the former tended to be higher than the latter. We consider the implications of these results for the calculation of the radiative forcing effect of ombrotrophic peatlands

    Transoral laser surgery for laryngeal carcinoma: has Steiner achieved a genuine paradigm shift in oncological surgery?

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    Transoral laser microsurgery applies to the piecemeal removal of malignant tumours of the upper aerodigestive tract using the CO2 laser under the operating microscope. This method of surgery is being increasingly popularised as a single modality treatment of choice in early laryngeal cancers (T1 and T2) and occasionally in the more advanced forms of the disease (T3 and T4), predomi- nantly within the supraglottis. Thomas Kuhn, the American physicist turned philosopher and historian of science, coined the phrase ‘paradigm shift’ in his groundbreaking book The Structure of Scientific Revolutions. He argued that the arrival of the new and often incompatible idea forms the core of a new paradigm, the birth of an entirely new way of thinking. This article discusses whether Steiner and col- leagues truly brought about a paradigm shift in oncological surgery. By rejecting the principle of en block resection and by replacing it with the belief that not only is it oncologically safe to cut through the substance of the tumour but in doing so one can actually achieve better results, Steiner was able to truly revolutionise the man- agement of laryngeal cancer. Even though within this article the repercussions of his insight are limited to the upper aerodigestive tract oncological surgery, his willingness to question other peoples’ dogma makes his contribution truly a genuine paradigm shift

    Improving health and well-being through community health champions: a thematic evaluation of a programme in Yorkshire and Humber.

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    AIMS: The contribution that lay people can make to the public health agenda is being increasingly recognised in research and policy literature. This paper examines the role of lay workers (referred to as 'community health champions') involved in community projects delivered by Altogether Better across Yorkshire and Humber. The aim of the paper is to describe key features of the community health champion approach and to examine the evidence that this type of intervention can have an impact on health. METHODS: A qualitative approach was taken to the evaluation, with two strands to gathering evidence: interviews conducted with different stakeholder groups including project leads, key partners from community and statutory sectors and community workers, plus two participatory workshops to gather the views of community health champions. Seven projects (from a possible 12) were identified to be involved in the evaluation. Those projects that allowed the evaluation team to explore fully the champion role (training, infrastructure, etc.) and how that works in practice as a mechanism for empowerment were selected. In total, 29 semi-structured interviews were conducted with project staff and partners, and 30 champions, varying in terms of age, gender, ethnicity and disability, took part in the workshops. RESULTS: Becoming a community health champion has health benefits such as increased self-esteem and confidence and improved well-being. For some champions, this was the start of a journey to other opportunities such as education or paid employment. There were many examples of the influence of champions extending to the wider community of family, friends and neighbours, including helping to support people to take part in community life. Champions recognised the value of connecting people through social networks, group activities, and linking people into services and the impact that that had on health and well-being. Project staff and partners also recognised that champions were promoting social cohesiveness and helping to integrate people into their community. CONCLUSIONS: The recent public health White Paper suggested that the Altogether Better programme is improving individual and community health as well as increasing social capital, voluntary activity and wider civic participation. This evaluation supports this statement and suggests that the community health champion role can be a catalyst for change for both individuals and communities
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