30,608 research outputs found

    The CCD and readout electronics for the OMC instrument on Integral

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    The Optical Monitoring Camera (OMC) on ESA's Integral gamma-ray astronomy satellite is devoted to optical wavelength observations simultaneously covering the same field-of-view as the gamma-ray and X-ray instruments. The OMC consists of a refracting telescope with a CCD as the imaging device in the focal plane. Here we describe the CCD and its associated readout electronics, in particular pointing out features of interest to users of the OMC instrument and its data

    Terrestrial laser scanning to deliver high-resolution topography of the upper Tarfala valley, arctic Sweden

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    Alpine valleys are experiencing rapidly changing physical, biological and geochemical processes as glacier masses diminish, snowfall patterns change and consequently as hillslopes and valley-floor landforms and sediments adjust. Measurement and understanding of these processes on a valley, landform and surface scale requires topographic data with sufficient spatial coverage and spatial resolution to resolve sources, fluxes and storages of sediment. Most ideally such topographic data will be of a resolution sufficient to resolve important spatial heterogeneity in land cover, topography and surface texture, for example. This study presents the first high-resolution (1 m grid cell size) and freely available topography for the upper part of the Tarfala valley, arctic Sweden. The topography was obtained using terrestrial laser scanning and a bespoke workflow is presented to most efficiently cover a 9.3 km2 area. The unprecedented spatial resolution of this topography, which is 15 times greater than that previously available, reveals a suite of alpine landforms. These landforms span multiple glacier forefields, a variety of bedrock surfaces, various hillslopes and types of mass movement, and valley floor glacial, fluvial and periglacial sediments, for example. Primary and second-order derivatives of this elevation data, and vertical transects are given and will assist future classification of landforms and thus assist future targeted field campaigns. Overall, this study presents (1) baseline data from which future re-surveys will enable quantitative analysis of a dynamic landscape, and (2) an efficient workflow that is readily transferable to any scientific study at any other site. Both of these project outputs will find widespread usage in future alpine studies

    A summary of the BARREL campaigns: Technique for studying electron precipitation.

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    BARREL observed electron precipitation over wide range of energy and timescalesPrecipitating electron distribution is determined using spectroscopy for 19 January 2013 eventBARREL timing data has accuracy within sampling interval of 0.05 s

    Proximate factors underpinning receiver responses to deceptive false alarm calls in wild tufted capuchin monkeys: is it counterdeception?

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    Previous research demonstrates that tufted capuchin monkeys use terrestrial predator alarm calls in a functionally deceptive manner to distract conspecifics when feeding on contestable resources, although the success of this tactic is limited because listeners frequently ignore these calls when given in such situations. While this decreased response rate is suggestive of a counterstrategy to deception by receivers, the proximate factors underpinning the behavior are unclear. The current study aims to test if the decreased response rate to alarm calls in competitive contexts is better explained by the perception of subtle acoustic differences between predator-elicited and deceptive false alarms, or by receivers varying their responses based on the context in which the signal is received. This was tested by first examining the acoustic structure of predator-elicited and deceptive false alarms for any potentially perceptible acoustic differences, and second by comparing the responses of capuchins to playbacks of each of predator-elicited and false alarms, played back in noncompetitive contexts. The results indicate that deceptive false alarms and predator-elicited alarms show, at best, minimal acoustic differences based on the structural features measured. Likewise, playbacks of deceptive false alarms elicited antipredator reactions at the same rate as did predator-elicited alarms, although there was a nonsignificant tendency for false alarms to be more likely to elicit escape reactions. The lack of robust acoustic differences together with the high response rate to false alarms in noncompetitive contexts suggests that the context in which the signal is received best explains receiver responses. It remains unclear, however, if listeners ascribe different meanings to the calls based on context, or if they generally ignore all signals in competitive contexts. Whether or not the decreased response rate of receivers directly stems from the deceptive use of the calls cannot be determined until these latter possibilities are rigorously tested

    Strength, Weakness, Opportunity, Threat (SWOT) Analysis of the Adaptations to Anatomical Education in the United Kingdom and Republic of Ireland in Response to the Covid‐19 Pandemic

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    The Covid-19 pandemic has driven the fastest changes to higher education across the globe, necessitated by social distancing measures preventing any face to face teaching. This has led to an almost immediate switch to distance learning by higher education institutions. Anatomy faces some unique challenges. Intrinsically, anatomy is a three-dimensional subject that requires a sound understanding of the relationships between structures, often achieved by the study of human cadaveric material, models and virtual resources. This study sought to identify the approaches taken in the United Kingdom and Republic of Ireland to deliver anatomical education through online means. Data were collected from 14 different universities in the United Kingdom and Republic of Ireland and compared adopting a thematic analysis approach. Once themes were generated, they were collectively brought together using a strength, weakness, opportunity, threat (SWOT) analysis. Key themes included the opportunity to develop new online resources and the chance to engage in new academic collaborations. Academics frequently mentioned the challenge that time constrains could place on the quality and effectiveness of these resources; especially as in many cases the aim of these resources is to compensate for a lack of exposure to cadaveric exposure. Comparisons of the actions taken by multiple higher education institutions reveals the ways that academics have tried to balance this demand. Discussions will facilitate decisions being made by higher education institutions regarding adapting the curriculum and assessment methods in anatomy

    Joining the conspiracy? Negotiating ethics and emotions in researching (around) AIDS in southern Africa

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    AIDS is an emotive subject, particularly in southern Africa. Among those who have been directly affected by the disease, or who perceive themselves to be personally at risk, talking about AIDS inevitably arouses strong emotions - amongst them fear, distress, loss and anger. Conventionally, human geography research has avoided engagement with such emotions. Although the ideal of the detached observer has been roundly critiqued, the emphasis in methodological literature on 'doing no harm' has led even qualitative researchers to avoid difficult emotional encounters. Nonetheless, research is inevitably shaped by emotions, not least those of the researchers themselves. In this paper, we examine the role of emotions in the research process through our experiences of researching the lives of 'Young AIDS migrants' in Malawi and Lesotho. We explore how the context of the research gave rise to the production of particular emotions, and how, in response, we shaped the research, presenting a research agenda focused more on migration than AIDS. This example reveals a tension between universalised ethics expressed through ethical research guidelines that demand informed consent, and ethics of care, sensitive to emotional context. It also demonstrates how dualistic distinctions between reason and emotion, justice and care, global and local are unhelpful in interpreting the ethics of research practice

    Responsibility modelling for civil emergency planning

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    This paper presents a new approach to analysing and understanding civil emergency planning based on the notion of responsibility modelling combined with HAZOPS-style analysis of information requirements. Our goal is to represent complex contingency plans so that they can be more readily understood, so that inconsistencies can be highlighted and vulnerabilities discovered. In this paper, we outline the framework for contingency planning in the United Kingdom and introduce the notion of responsibility models as a means of representing the key features of contingency plans. Using a case study of a flooding emergency, we illustrate our approach to responsibility modelling and suggest how it adds value to current textual contingency plans

    Estimating the furrow infiltration characteristic from a single advance point

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    Management and control of surface irrigation, in particular furrow irrigation, is limited by spatio-temporal soil infiltration variability as well as the high cost and time associated with collecting intensive field data for estimation of the infiltration characteristics. Recent work has proposed scaling the commonly used infiltration function by using a model infiltration curve and a single advance point for every other furrow in an irrigation event. Scaling factors were calculated for a series of furrows at two sites and at four points down the length of the field (0.25 L, 0.5 L, 0.75 L and L). Differences in the value of the scaling factor with distance were found to be a function of the shape of the advance curves. It is concluded that use of points early in the advance results in a substantial loss of accuracy and should be avoided. The scaling factor was also strongly correlated with the furrow-wetted perimeter suggesting that the scaling is an appropriate way of both predicting and accommodating the effect of the hydraulic variability

    RINGO3: a multi-colour fast response polarimeter

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    GRB jets contain rapidly moving electrons which will spiral around magnetic field lines. This causes them to emit polarized synchrotron emission. We have built a series of polarimeters (RINGO and RINGO2) to investigate this by measuring the polarization of optical light from GRBs at a certain single wavelength. The instruments are mounted on the Liverpool Telescope, which is a fully robotic (i.e. unmanned) telescope on La Palma which reacts to triggers from satellites such as the NASA SWIFT mission. This has had great success, with the first ever detections of early time optical polarization being made. In addition, the first measurements of the change in optical polarization from a GRB as the jet expands have recently been obtained. In this paper we describe the design and construction of RINGO3. This will be a multi-colour instrument that can observe simultaneously at three wavelengths. By doing so we will be able to unambiguously identify where in the burst the polarized emission is coming from. This will allow us to distinguish between three possibilities: (1) Magnetic instabilities generated in the shock front, (2) Line of sight effects and (3) Large-scale magnetic fields present throughout the relativistic outflow. The instrument design combines a rapidly rotating polaroid, specially designed polarization insensitive dichroic mirrors and three electron multiplying CCD cameras to provide simultaneous wavelength coverage with a time resolution of 1 second

    Quantifying uncertainty in acoustic measurements of tidal flows using a ‘Virtual’ Doppler Current Profiler

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Accurate characterisation of flows at tidal sites can enable the developers of tidal stream energy projects to design and model the loads on, and the performance of, tidal energy converters. Acoustic Doppler technology is versatile in the measurement of sea conditions; however, this technology can be limited in its effectiveness at measuring the small-scale kinematic fluctuations caused by waves and turbulence. A Virtual Doppler Current Profiler (VDCP) is used to sample a simulated tidal flow to understand the limitations of this type of measurement instrument whilst recording the small timescale kinematics of waves and turbulence in tidal currents. Results demonstrate the phase dependency of velocity measurements averaged between two acoustic beams and provide a theoretical error for wave and turbulence characteristics sampled under a range of conditions. Spectral moments of the subsurface longitudinal wave orbital velocities recorded by the VDCP can be between 0.1 and 9 times those measured at a point for certain turbulent current conditions, turbulence intensity measurements may vary between 0.2 and 1.5 times the inputted value in low wave conditions and turbulence length scale calculation can also vary hugely dependent on both current and wave conditions. The continuation of this work will enable effective comparison of a linear model for tidal flow kinematics against field measurements from UK tidal site data, and subsequently validate numerical models for the testing of tidal turbines.This work was supported by the Industrial Centre for Offshore Renewable Energy (IDCORE) with funding from the Energy Technologies Institute and the Research Councils Energy Programme [grant number EP/J500847/1] and DNV GL
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