370 research outputs found

    Quantifying the transboundary contribution of nitrogen oxides to UK air quality

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    Nitrogen dioxide (NO2) pollution is an important contributor to poor air quality (AQ) and a significant cause of premature deaths in the UK. Although transboundary (i.e., international) transport of pollution to the UK is believed to have an impact on UK pollutant concentrations, large uncertainties remain in these estimates. Therefore, the extent to which emission reductions in neighbouring countries would benefit UK AQ relative to local emission reductions also remains unknown. We have used a back‐trajectory model in conjunction with synoptic scale classifications of UK circulation patterns (Lamb Weather Types [LWT]), to quantify the accumulation of nitrogen oxide (NO x = NO2 + NO) emissions in air masses en‐route to the UK. This novel method presents a computationally inexpensive and useful method of quantifying the accumulation of pollutants under different circulation patterns. We find the highest accumulated NO x totals occur under south‐easterly and southerly flows (>15 Όg⋅m−2), with a substantial contribution from outwith the UK (>25%). In contrast, the total accumulated NO x under northerly and westerly flows is lower (∌10 ÎŒg⋅m−2), and dominated by UK emissions (>95%). This indicates that European emissions can contribute substantially to UK local‐scale pollution in urban areas under south‐easterly and southerly flows. The sensitivity of integrated NO x emission totals under different air masses is investigated by modelling future European emission contributions based on emission reduction targets. Under targets set by the European Union, there would be a decrease in accumulated NO x emissions in London under most wind directions except for north‐westerly, westerly and northerly flow. The largest benefits to UK AQ from transboundary contributions occur with emission reductions in the Benelux region, due to its close proximity and high NO x emission rates, emphasising the importance of international cooperation in improving local AQ

    Developing national obesity policy in middle-income countries: a case study from North Africa

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    Background The prevalence of overweight and obesity is a rapidly growing threat to public health in both Morocco and Tunisia, where it is reaching similar proportions to high-income countries. Despite this, a national strategy for obesity does not exist in either country. The aim of this study was to explore the views of key stakeholders towards a range of policies to prevent obesity, and thus guide policy makers in their decision making on a national level. Methods Using Multicriteria Mapping, data were gathered from 82 stakeholders (from 33 categories in Morocco and 36 in Tunisia) who appraised 12 obesity policy options by reference to criteria of their own choosing. Results The feasibility of policies in practical or political terms and their cost were perceived as more important than how effective they would be in reducing obesity. There was most consensus and preference for options targeting individuals through health education, compared with options that aimed at changing the environment, i.e. modifying food supply and demand (providing healthier menus/changing food composition/food sold in schools); controlling information (advertising controls/mandatory labelling) or improving access to physical activity. In Tunisia, there was almost universal consensus that at least some environmental-level options are required, but in Morocco, participants highlighted the need to raise awareness within the population and policy makers that obesity is a public health problem, accompanied by improving literacy before such measures would be accepted. Conclusion Whilst there is broad interest in a range of policy options, those measures targeting behaviour change through education were most valued. The different socioeconomic, political and cultural contexts of countries need to be accounted for when prioritizing obesity policy. Obesity was not recognized as a major public health priority; therefore, convincing policy makers about the need to prioritize action to prevent obesity, particularly in Morocco, will be a crucial first step

    Simulation of weather-driven deterioration of clay embankments

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    Clay embankments used for road, rail, and flood defense infrastructure experience several weather-driven deterioration processes that lead to a progressive degradation in their hydromechanical performance. This paper presents a numerical modeling approach that accounts for the development of desiccation cracking in clay embankments. Specifically, a bimodal soil water retentivity model was adopted to capture the long-term hydraulic behavior of clay embankments prone to weather-driven desiccation cracking. A numerical model was developed for a heavily instrumented and monitored full-scale research embankment with long-term field data. The model was able to capture the variation of near-surface soil moisture and matric suction over a monitored period of nine years in response to weather cycles. The developed and validated numerical modeling approach enables forecasting of the long-term performance of clay embankments under a range of future climate scenarios

    ACHILLES Reading Guide 3: Asset scale deterioration

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    The deterioration of earthworks reduces theirserviceable performance and increases thelikelihood of instability. This can havesignificant impacts on the safe and reliableoperation of the transportation networks thatthey support. These deterioration processesare weather-driven and may lead to failuremany years after construction even in theabsence of increased mechanical loads.Evidence also indicates that climate changewill increase rates of asset deterioration andreduce time to failure. This documentsummarises the key conclusions on assetdeterioration drawn from the ACHILLES bodyof work. A more detailed overview of theACHILLES concept can be found in ReadingGuide 1 [1], the project website (achilles-grant.org.uk), and the following papers: [2,3]

    Student perceptions of a healthy university

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    As complex environments within which individuals and populations operate, universities present important contexts for understanding and addressing health issues. The healthy university is an example of the settings approach, which adopts a whole system perspective, aiming to make places within which people, learn, live, work and play supportive to health and wellbeing. The UK Healthy Universities Network has formulated an online toolkit, which includes a self-review tool, intended to enable universities to assess what actions they need to take to develop as a healthy university. This paper presents findings from consultative research undertaken with students from universities in England, Scotland and Wales, which explored what they believe represents a healthy university. Methods Student surveys and focus groups were used to collect data across eleven universities in England, Scotland and Wales. A priori themes were used to develop our own model for a healthy university, and for the thematic coding phase of analysis. Findings A healthy university would promote student health and wellbeing in every aspect of its business from its facilities and environment through to its curriculum. Access to reasonably priced healthy food and exercise facilities were key features of a healthy university for students in this study. The Self Review Tool has provided a crucial start for universities undertaking the journey towards becoming a healthy university. In looking to the future both universities and the UK Healthy Universities Network will now need to look at what students want from their whole university experience, and consider how the Self Review Tool can help universities embrace a more explicit conceptual framework. Conclusion The concept of a healthy university that can tailor its facilities and supportive environments to the needs of its students will go some way to developing students who are active global citizens and who are more likely to value and prioritise health and wellbeing, in the short and long term through to their adult lives

    Meson Structure in Deep Inelastic Scattering

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    We study the deep inelastic structure functions of mesons within the Nambu and Jona-Lasinio model. We calculate the valence quark distributions in π\pi , KK , and ρ\rho mesons at the low energy model scale, which are evoluted to the experimental momentum scale in terms of the Altarelli-Parisi equation. The resulting distribution functions show reasonable agreements with experiment. We also discuss the semi-inclusive lepton nucleon scattering process with a slow nucleon in coincidence in the final state, which reveals the off-shell structure of the pion.Comment: 31 pages with 16 figures as uuencoded postscript files, TMU-NT-940101 (plain LaTeX

    The histone chaperones Vps75 and Nap1 form ring-like, tetrameric structures in solution

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    NAP-1 fold histone chaperones play an important role in escorting histones to and from sites of nucleosome assembly and disassembly. The two NAP-1 fold histone chaperones in budding yeast, Vps75 and Nap1, have previously been crystalized in a characteristic homodimeric conformation. In this study, a combination of small angle X-ray scattering, multi angle light scattering and pulsed electron–electron double resonance approaches were used to show that both Vps75 and Nap1 adopt ring-shaped tetrameric conformations in solution. This suggests that the formation of homotetramers is a common feature of NAP-1 fold histone chaperones. The tetramerisation of NAP-1 fold histone chaperones may act to shield acidic surfaces in the absence of histone cargo thus providing a ‘self-chaperoning’ type mechanism

    Short-lived Nuclei in the Early Solar System: Possible AGB Sources

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    (Abridged) We review abundances of short-lived nuclides in the early solar system (ESS) and the methods used to determine them. We compare them to the inventory for a uniform galactic production model. Within a factor of two, observed abundances of several isotopes are compatible with this model. I-129 is an exception, with an ESS inventory much lower than expected. The isotopes Pd-107, Fe-60, Ca-41, Cl-36, Al-26, and Be-10 require late addition to the solar nebula. Be-10 is the product of particle irradiation of the solar system as probably is Cl-36. Late injection by a supernova (SN) cannot be responsible for most short-lived nuclei without excessively producing Mn-53; it can be the source of Mn-53 and maybe Fe-60. If a late SN is responsible for these two nuclei, it still cannot make Pd-107 and other isotopes. We emphasize an AGB star as a source of nuclei, including Fe-60 and explore this possibility with new stellar models. A dilution factor of about 4e-3 gives reasonable amounts of many nuclei. We discuss the role of irradiation for Al-26, Cl-36 and Ca-41. Conflict between scenarios is emphasized as well as the absence of a global interpretation for the existing data. Abundances of actinides indicate a quiescent interval of about 1e8 years for actinide group production in order to explain the data on Pu-244 and new bounds on Cm-247. This interval is not compatible with Hf-182 data, so a separate type of r-process is needed for at least the actinides, distinct from the two types previously identified. The apparent coincidence of the I-129 and trans-actinide time scales suggests that the last actinide contribution was from an r-process that produced actinides without fission recycling so that the yields at Ba and below were governed by fission.Comment: 92 pages, 14 figure files, in press at Nuclear Physics
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