8,825 research outputs found
How do adolescents talk about self-harm: a qualitative study of disclosure in an ethnically diverse urban population in England
The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2458/13/572.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
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Lessons from technology development for energy and sustainability
This is the author accepted manuscript. The final version is available from Cambridge University Press via http://dx.doi.org/10.1557/mre.2016.3The growth of the ecological footprint of a human population about to increase from 7B now to 9B in 2050 raises serious concerns about how to live both more efficiently and with less permanent impacts on the finite world. One present focus is the future of our climate, where the level of concern has prompted actions across the world in mitigation of the emissions of CO2. An examination of successful and failed introductions of technology over the last 200 years generates several lessons that should be kept in mind as we proceed to 80% decarbonise the world economy by 2050. I will argue that all the actions taken together until now to reduce our emissions of carbon dioxide will not achieve a serious reduction, and in some cases they will actually make matters worse. In practice, the scale and the different specific engineering challenges of the decarbonisation project are without precedent in human history. This means that any new technology introductions need to be able to meet the huge implied capabilities. An altogether more sophisticated public debate is urgently needed on appropriate actions that (i) considers the full range of threats to humanity, and (ii) weighs more carefully both the upsides and downsides of taking any action, and of not taking that action
Scaling prediction errors to reward variability benefits error-driven learning in humans.
Effective error-driven learning requires individuals to adapt learning to environmental reward variability. The adaptive mechanism may involve decays in learning rate across subsequent trials, as shown previously, and rescaling of reward prediction errors. The present study investigated the influence of prediction error scaling and, in particular, the consequences for learning performance. Participants explicitly predicted reward magnitudes that were drawn from different probability distributions with specific standard deviations. By fitting the data with reinforcement learning models, we found scaling of prediction errors, in addition to the learning rate decay shown previously. Importantly, the prediction error scaling was closely related to learning performance, defined as accuracy in predicting the mean of reward distributions, across individual participants. In addition, participants who scaled prediction errors relative to standard deviation also presented with more similar performance for different standard deviations, indicating that increases in standard deviation did not substantially decrease "adapters'" accuracy in predicting the means of reward distributions. However, exaggerated scaling beyond the standard deviation resulted in impaired performance. Thus efficient adaptation makes learning more robust to changing variability.This work was supported by the Wellcome Trust and the Niels Stensen Foundation.This is the final version of the article. It first appeared from the American Physiological Society via http://dx.doi.org/10.1152/jn.00483.201
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Extremely uniform tunnel barriers for low-cost device manufacture
We report on the final steps needed to achieve the
level of control over the properties of single tunnel barriers of
AlAs needed to allow the manufacture of high-volume low-cost
microwave and millimeter-waves detectors. We achieve a
1% standard deviation of the current–voltage characteristics
across 2-in wafers and average currents from different wafers
varying by 1%, when modeling shows that a monolayer error in
the AlAs barrier layer thickness would result in a 270% change
in the same electrical characteristics.This work was supported in part
by the Engineering and Physical Science Research Council and in part by
the Royal Society’s Mercer Innovation Award.This is the final version. It was first published by IEEE at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=7097674
The effect of Mg location on Co-Mg-Ru/γ-Al2O3 Fischer–Tropsch catalysts
© 2016 The Author(s) Published by the Royal Society. All rights reserved.The effectiveness of Mg as a promoter of Co-Ru/γ-Al2O3 Fischer-Tropsch catalysts depends on how and when the Mg is added. When the Mg is impregnated into the support before the Co and Ru addition, some Mg is incorporated into the support in the form of MgxAl2O3+x if the material is calcined at 550°C or 800°C after the impregnation, while the remainder is present as amorphous MgO/MgCO3 phases. After subsequent Co-Ru impregnation MgxCo3-xO4 is formed which decomposes on reduction, leading to Co(0) particles intimately mixed with Mg, as shown by high-resolution transmission electron microscopy. The process of impregnating Co into an Mg-modified support results in dissolution of the amorphous Mg, and it is this Mg which is then incorporated into MgxCo3-xO4. Acid washing or higher temperature calcination after Mg impregnation can remove most of this amorphous Mg, resulting in lower values of x in MgxCo3-xO4. Catalytic testing of these materials reveals that Mg incorporation into the Co oxide phase is severely detrimental to the site-Time yield, while Mg incorporation into the support may provide some enhancement of activity at high temperature
Mass Drug Administration and beyond: how can we strengthen health systems to deliver complex interventions to eliminate neglected tropical diseases?
Achieving the 2020 goals for Neglected Tropical Diseases (NTDs) requires scale-up of Mass Drug Administration (MDA) which will require long-term commitment of national and global financing partners, strengthening national capacity and, at the community level, systems to monitor and evaluate activities and impact. For some settings and diseases, MDA is not appropriate and alternative interventions are required. Operational research is necessary to identify how existing MDA networks can deliver this more complex range of interventions equitably. The final stages of the different global programmes to eliminate NTDs require eliminating foci of transmission which are likely to persist in complex and remote rural settings. Operational research is required to identify how current tools and practices might be adapted to locate and eliminate these hard-to-reach foci. Chronic disabilities caused by NTDs will persist after transmission of pathogens ceases. Development and delivery of sustainable services to reduce the NTD-related disability is an urgent public health priority. LSTM and its partners are world leaders in developing and delivering interventions to control vector-borne NTDs and malaria, particularly in hard-to-reach settings in Africa. Our experience, partnerships and research capacity allows us to serve as a hub for developing, supporting, monitoring and evaluating global programmes to eliminate NTDs
Validity and interunit reliability of 10 Hz and 15 Hz GPS units for assessing athlete movement demands
The purpose of this study was to assess the validity and interunit reliability of 10 Hz (Catapult) and 15 Hz (GPSports) Global Positioning System (GPS) units and investigate the differences between these units as measures of team sport athlete movement demands. A team sport simulation circuit was completed by 8 trained male participants. The movement demands examined included: total distance covered (TD), average peak speed, and the distance covered, time spent, and the number of efforts performed low-speed running (0.00-13.99 km·h-1), high-speed running (14.00-19.99 km·h-1), and very highspeed running (>20.00 km·h-1). The degree of difference between the 10 Hz and the 15 Hz GPS units and validity was assessed using a paired samples t-test. Pearson's correlations were also used for validity assessment. Interunit reliability was established using percentage typical error of measurement (%TEM) and intraclass correlations. The findings revealed that 10 Hz GPS units were a valid (p > 0.05) and reliable (%TEM = 1.3%) measure of TD. In contrast, the 15 Hz GPS units exhibited lower validity for TD and average peak speed. Further, as the speed of movement increased the level of error for the 10 Hz and 15 Hz GPS units increased (% TEM = 0.8-19.9). The findings from this study suggest that comparisons should not be undertaken between 10 Hz and 15 Hz GPS units. In general, the 10 Hz GPS units measured movement demands with greater validity and interunit reliability than the 15 Hz units, however, both 10 Hz and 15 Hz units provided the improved measures of movement demands in comparison to 1 Hz and 5 Hz GPS units. © 2014 National Strength and Conditioning Association
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