3,004 research outputs found

    Efficient and automatic methods for flexible regression on spatiotemporal data, with applications to groundwater monitoring

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    Fitting statistical models to spatiotemporal data requires finding the right balance between imposing smoothness and following the data. In the context of P-splines, we propose a Bayesian framework for choosing the smoothing parameter which allows the construction of fully-automatic data-driven methods for fitting flexible models to spatiotemporal data. An implementation, which is highly computationally efficient and which exploits the sparsity of the design and penalty matrices, is proposed. The findings are illustrated using a simulation study and two examples, all concerned with the modelling of contaminants in groundwater. This suggests that the proposed strategy is more stable that competing methods based on the use of criteria such as GCV and AIC

    Shade as enrichment : testing preferences for shelter in two model fish species

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    N.A.R.J. was supported by an Fisheries Society of the British Isles studentship, F.M.J. by the St Andrews School of Biology and H.C.S.-J. by the John Templeton Foundation.We compared preferences shown by zebrafish Danio rerio and three‐spined stickleback Gasterosteus aculeatus for shelter provided by above‐tank shade and artificial plants. Zebrafish showed no preference for either shelter, whereas sticklebacks showed a preference for both shelter types over open areas and for shade over plants. Our results suggest shade may be used as enrichment for captive fish and re‐emphasise the importance of species‐specific welfare considerations.PostprintPeer reviewe

    Shape My Brecon Beacons

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    Shape My Brecon Beacons is a guide is for town and community councils, local residents, community groups and residents’ associations embarking on producing a Place Plan in the Brecon Beacons National Park. It guides the reader through the process of producing the plan and explains how it could be delivered. It offers a step-by-step guide to setting up a Place Plan Team, understanding the sense of place, effectively consulting with local people, producing a realistic plan that fits within planning policy and ensuring community ownership of a plan

    Independent effects of bottom-up temporal expectancy and top-down spatial attention. An audiovisual study using rhythmic cueing

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    Selective attention to a spatial location has shown enhanced perception and facilitate behavior for events at attended locations. However, selection relies not only on where but also when an event occurs. Recently, interest has turned to how intrinsic neural oscillations in the brain entrain to rhythms in our environment, and, stimuli appearing in or out of sync with a rhythm have shown to modulate perception and performance. Temporal expectations created by rhythms and spatial attention are two processes which have independently shown to affect stimulus processing but it remains largely unknown how, and if, they interact. In four separate tasks, this study investigated the effects of voluntary spatial attention and bottom-up temporal expectations created by rhythms in both unimodal and crossmodal conditions. In each task the participant used an informative cue, either color or pitch, to direct their covert spatial attention to the left or right, and respond as quickly as possible to a target. The lateralized target (visual or auditory) was then presented at the attended or unattended side. Importantly, although not task relevant, the cue was a rhythm of either flashes or beeps. The target was presented in or out of sync (early or late) with the rhythmic cue. Results showed participants were faster responding to spatially attended compared to unattended targets in all tasks. Moreover, there was an effect of rhythmic cueing upon response times in both unimodal and crossmodal conditions. Responses were faster to targets presented in sync with the rhythm compared to when they appeared too early in both crossmodal tasks. That is, rhythmic stimuli in one modality influenced the temporal expectancy in the other modality, suggesting temporal expectancies created by rhythms are crossmodal. Interestingly, there was no interaction between top-down spatial attention and rhythmic cueing in any task suggesting these two processes largely influenced behavior independently

    Passive traps and sampling bias: social effects and personality affect trap-entry by sticklebacks

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    This research was funded by the University of St Andrews.Researchers routinely quantify the behaviour of subsets of animals, using their findings to make inferences about wider populations. Broader conclusions, however, may be inaccurate if the subjects that are tested are not representative of these populations. One way that this can arise is through sampling bias, which can occur if the method of collecting the test subjects disproportionately selects those with particular attributes, such that they end up being over‐ or under represented within the sample. Passive traps are associated with such sampling biases and have been shown to target certain behavioural phenotypes in a range of species. Here we asked whether funnel‐type fish traps were more likely to target more active and more social sticklebacks (Gasterosteus aculeatus). We found that more subjects entered the traps when they already contained conspecifics and that individual measures of activity predicted trap entry, with more active fish being captured sooner both when the traps already contained conspecifics and when they were empty. Unexpectedly, less‐social fish were captured sooner when the traps contained conspecifics. Sampling biases have the potential to skew the data collected by researchers and we therefore highlight the need to acknowledge and discuss potential for sampling biases and any consequences that may arise from this in published work. In the longer term, research that estimates the potential for sampling biases for various collection methods and species would be a valuable resource for helping to devise more representative sampling designs.Publisher PDFPeer reviewe

    Does language loss follow a principled structural path? Evidence from Jersey Norman French

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    ABSTRACTThis study examines contact-induced change in Jèrriais, the severely endangered Norman variety currently spoken by some 1% of the population of Jersey, one of the British Channel Islands. Today, English dominates all linguistic domains of island life, and all speakers of Jèrriais are bilingual. The analysis uses original data to test empirically whether Myers-Scotton's (2002) five theoretical assumptions about the structural path of language attrition (broadly defined as language loss at the level of the individual) also have relevance for the process of language obsolescence (broadly defined as language loss at the level of the community). It explores i) whether Jèrriais is undergoing contact influenced language change owing to its abstract grammatical structure being split and recombined with English, a hypothesis related to Myers-Scotton's Abstract Level model; and ii) whether different morpheme types of Jèrriais are related to the production process in different ways and are, accordingly, more or less susceptible to change during the process of language obsolescence, a hypothesis related to Myers-Scotton's 4-M model. In addition to its contribution to linguistic theory, this study increases existing knowledge about Jèrriais and makes data from this language available for systematic comparison with other languages.</jats:p

    Development of an Ultraflex-Based Thin Film Solar Array for Space Applications

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    As flexible thin film photovoltaic (FTFPV) cell technology is developed for space applications, integration into a viable solar array structure that optimizes the attributes of this cell technology is critical. An advanced version of ABLE'sS UltraFlex solar array platform represents a near-term, low-risk approach to demonstrating outstanding array performance with the implementation of FTFPV technology. Recent studies indicate that an advanced UltraFlex solar array populated with 15% efficient thin film cells can achieve over 200 W/kg EOL. An overview on the status of hardware development and the future potential of this technology is presented
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