146 research outputs found

    Developing FeAST for mobile marine species.

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    Background The Feature Activity Sensitivity Tool (FeAST) is hosted on the Marine Scotland (MS) website and supported by Scottish Natural Heritage (SNH) and the Joint Nature Conservation Committee (JNCC). Its purpose is to enable high-level assessment of the sensitivity of features of conservation value, present in Scottish seas, to different pressures resulting from human activities. The overall aim of this project is to enable the FeAST methodology to be adapted for mobile marine species and to consider for which species sensitivity assessment at an individual level, as opposed to the population level, was more appropriate, and why. Main findings Existing approaches to Sensitivity Assessment, including FeAST, Marine Evidence-based Sensitivity Assessment (MarESA) and Highly Mobile Species Sensitivity (HMSS) methods, entail the estimation of changes in population expressed as a percentage of the existing population. They assess the sensitivity of a hypothetical population and are not site-specific. It was difficult to define, categorically, when it is most appropriate to use an individualbased rather than population-based approach to sensitivity assessment. Accordingly, two sets of indicators were identified which tended to favour such an approach. We suggest that Individual-based Sensitivity Assessment (IBSA) should be applied in species where the loss of a single individual (or small number of individuals) has the potential to affect the survival of the population adversely or where legislation protecting the species is implemented on an individual level. Such species are likely to be Kstrategists that are slow to reproduce with a long lifespan, slow growth rates, late reproduction, high parental investment in their young, low fecundity and, probably, small population sizes. We identified those species with legislative protection at an individual level, in Scotland, from criteria and species lists set out in the Wildlife and Countryside Act (W&C) 1981, the Habitats Directive and the Marine (Scotland) Act 2010. All the cetaceans, seals, marine reptiles, sharks and rays listed under W&C 1981 and as European Protected Species would be suitable for IBSA using this approach, together with the otter and notable fin-fish, i.e. the Atlantic sturgeon, Allis shad, Twaite shad and European river lamprey. RESEARCH REPORT Summary ii In addition, the sharks and rays listed as mobile PMFs are also suitable, together with the Atlantic halibut, blue ling, European eel, orange roughy, and round-nose grenadier. A list of another seven fin-fish requires further consideration. The remaining fin-fish listed as PMFs are probably not suitable under our suggested indicators. However, the life history characteristics examined represent a short review of the characteristics that influence population recovery and do not take into account larval/juvenile mortality, recruitment, population dynamics, or restricted breeding sites such as nursery areas in fish or rivers and estuaries in anadromous fish. In addition, the cut-off values for life history characteristics are subjective rather than definitive. Further study is required to expand and test the application of the above list of indicators and the IBSA approach to a wider range of species than considered here. An individual-based tolerance scale is suggested. We avoided a binary scale (dead/alive) and suggested a scale from ‘dead’ through different levels of impairments due to physical injury and behavioural changes. We slightly amended the existing FeAST recovery scale to emphasize its application to the recovery of individuals rather than that of populations. The FeAST sensitivity matrix was also amended slightly to highlight the fact that no recovery was possible from direct mortality. The existing FeAST scales for ‘confidence’ and ‘evidence’ were adopted. The suggested individual-based approach was tested on two pilot species: Risso’s dolphin and the harbour seal. Contrary to initial concerns, the suggested scales did not result in binary scores, that is, just mortality or no mortality. Both pilot assessments gave a range of scores for tolerance, recovery and, hence, sensitivity. Assessing on an individual level was found to simplify the assessment of tolerance. It was often very straightforward to assess whether an individual was likely to suffer injury or mortality from an impact. The suggested individual-based approach does not take the likelihood of the impact occurring or the extent of the impact into account at any point. Many of the pressures to which the assessed species are highly sensitive may be very unlikely to have a population level impact, due to their low likelihood of occurrence. It should also be noted that the revision of benchmarks and scales for highly mobile species in FeAST means that the resultant sensitivity assessment will differ from those generated under the MarESA and HMSS approaches, and that their sensitivity scores for the same species will not be directly comparable. Overall, the suggested Individual-based Sensitivity Assessment (IBSA) approach was used successfully to assess the sensitivity of two highly mobile species. More species need to be assessed to test the approach fully and to develop examples and guidance on the application of the individual-based tolerance scale to other highly mobile specie

    High sensitivity measurement of 224Ra and 226Ra in water with an improved hydrous titanium oxide technique at the Sudbury Neutrino Observatory

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    The existing hydrous titanium oxide (HTiO) technique for the measurement of 224Ra and 226Ra in the water at the Sudbury Neutrino Observatory (SNO) has been changed to make it faster and less sensitive to trace impurities in the HTiO eluate. Using HTiO-loaded filters followed by cation exchange adsorption and HTiO co-precipitation, Ra isotopes from 200-450 tonnes of heavy water can be extracted and concentrated into a single sample of a few millilitres with a total chemical efficiency of 50%. Combined with beta-alpha coincidence counting, this method is capable of measuring 2.0x10^3 uBq/kg of 224Ra and 3.7x10^3 uBq/kg of 226Ra from the 232Th and 238U decay chains, respectively, for a 275 tonne D2O assay, which are equivalent to 5x10^16 g Th/g and 3x10^16 g U/g in heavy water.Comment: 8 Pages, 2 figures and 2 table

    Field measurements of horizontal forward motion velocities of terrestrial dust devils: towards a proxy for ambient winds on Mars and Earth

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    Dust devils – convective vortices made visible by the dust and debris they entrain – are common in arid environments and have been observed on Earth and Mars. Martian dust devils have been identified both in images taken at the surface and in remote sensing observations from orbiting spacecraft. Observations from landing craft and orbiting instruments have allowed the dust devil translational forward motion (ground velocity) to be calculated, but it is unclear how these velocities relate to the local ambient wind conditions, for (i) only model wind speeds are generally available for Mars, and (ii) on Earth only anecdotal evidence exists that compares dust devil ground velocity with ambient wind velocity. If dust devil ground velocity can be reliably correlated to the ambient wind regime, observations of dust devils could provide a proxy for wind speed and direction measurements on Mars. Hence, dust devil ground velocities could be used to probe the circulation of the martian boundary layer and help constrain climate models or assess the safety of future landing sites. We present results from a field study of terrestrial dust devils performed in the southwest USA in which we measured dust devil horizontal velocity as a function of ambient wind velocity. We acquired stereo images of more than a hundred active dust devils and recorded multiple size and position measurements for each dust devil. We used these data to calculate dust devil translational velocity. The dust devils were within a study area bounded by 10 m high meteorology towers such that dust devil speed and direction could be correlated with the local ambient wind speed and direction measurements. Daily (10:00 to 16:00 local time) and two-hour averaged dust devil ground speeds correlate well with ambient wind speeds averaged over the same period. Unsurprisingly, individual measurements of dust devil ground speed match instantaneous measurements of ambient wind speed more poorly; a 20-minute smoothing window applied to the ambient wind speed data improves the correlation. In general, dust devils travel 10-20% faster than ambient wind speed measured at 10 m height, suggesting that their ground speeds are representative of the boundary layer winds a few tens of meters above ground level. Dust devil ground motion direction closely matches the measured ambient wind direction. The link between ambient winds and dust devil ground velocity demonstrated here suggests that a similar one should apply on Mars. Determining the details of the martian relationship between dust devil ground velocity and ambient wind velocity might require new in-situ or modelling studies but, if completed successfully, would provide a quantitative means of measuring wind velocities on Mars that would otherwise be impossible to obtain

    A framework for the practical science necessary to restore sustainable, resilient, and biodiverse ecosystems

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    Demand for restoration of resilient, self-sustaining, and biodiverse natural ecosystems as a conservation measure is increasing globally; however, restoration efforts frequently fail to meet standards appropriate for this objective. Achieving these standards requires management underpinned by input from diverse scientific disciplines including ecology, biotechnology, engineering, soil science, ecophysiology, and genetics. Despite increasing restoration research activity, a gap between the immediate needs of restoration practitioners and the outputs of restoration science often limits the effectiveness of restoration programs. Regrettably, studies often fail to identify the practical issues most critical for restoration success. We propose that part of this oversight may result from the absence of a considered statement of the necessary practical restoration science questions. Here we develop a comprehensive framework of the research required to bridge this gap and guide effective restoration. We structure questions in five themes: (1) setting targets and planning for success, (2) sourcing biological material, (3) optimizing establishment, (4) facilitating growth and survival, and (5) restoring resilience, sustainability, and landscape integration. This framework will assist restoration practitioners and scientists to identify knowledge gaps and develop strategic research focused on applied outcomes. The breadth of questions highlights the importance of cross-discipline collaboration among restoration scientists, and while the program is broad, successful restoration projects have typically invested in many or most of these themes. Achieving restoration ecology's goal of averting biodiversity losses is a vast challenge: investment in appropriate science is urgently needed for ecological restoration to fulfill its potential and meet demand as a conservation too

    Highly-parallelized simulation of a pixelated LArTPC on a GPU

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    The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

    The computation of physical ephemerides of planets and satellites

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    SIGLELD:6015.345(NAO-TN-53). / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    The effect of atmospheric refraction on laser ranging data

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    SIGLELD:6015.345(NAO-TN--59). / BLDSC - British Library Document Supply CentreGBUnited Kingdo
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