48 research outputs found

    Middle and Late Pleistocene environmental history of the Marsworth area, south-central England

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    To elucidate the Middle and Late Pleistocene environmental history of south-central England, we report the stratigraphy, sedimentology, palaeoecology and geochronology of some deposits near the foot of the Chiltern Hills scarp at Marsworth, Buckinghamshire. The Marsworth site is important because its sedimentary sequences contain a rich record of warm stages and cold stages, and it lies close to the Anglian glacial limit. Critical to its history are the origin and age of a brown pebbly silty clay (diamicton) previously interpreted as weathered till. The deposits described infill a river channel incised into chalk bedrock. They comprise clayey, silty and gravelly sediments, many containing locally derived chalk and some with molluscan, ostracod and vertebrate remains. Most of the deposits are readily attributed to periglacial and fluvial processes, and some are dated by optically stimulated luminescence to Marine Isotope Stage (MIS) 6. Although our sedimentological data do not discriminate between a glacial or periglacial interpretation of the diamicton, amino-acid dating of three molluscan taxa from beneath it indicates that it is younger than MIS 9 and older than MIS 5e. This makes a glacial interpretation unlikely, and we interpret the diamicton as a periglacial slope deposit. The Pleistocene history reconstructed for Marsworth identifies four key elements: (1) Anglian glaciation during MIS 12 closely approached Marsworth, introducing far-travelled pebbles such as Rhaxella chert and possibly some fine sand minerals into the area. (2) Interglacial environments inferred from fluvial sediments during MIS 7 varied from fully interglacial conditions during sub-stages 7e and 7c, cool temperate conditions during sub-stage 7b or 7a, temperate conditions similar to those today in central England towards the end of the interglacial, and cool temperate conditions during sub-stage 7a. (3) Periglacial activity during MIS 6 involved thermal contraction cracking, permafrost development, fracturing of chalk bedrock, fluvial activity, slopewash, mass movement and deposition of loess and coversand. (4) Fully interglacial conditions during sub-stage 5e led to renewed fluvial activity, soil formation and acidic weathering

    Genome-wide meta-analysis identifies 127 open-angle glaucoma loci with consistent effect across ancestries

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    Primary open-angle glaucoma (POAG), is a heritable common cause of blindness world-wide. To identify risk loci, we conduct a large multi-ethnic meta-analysis of genome-wide association studies on a total of 34,179 cases and 349,321 controls, identifying 44 previously unreported risk loci and confirming 83 loci that were previously known. The majority of loci have broadly consistent effects across European, Asian and African ancestries. Cross-ancestry data improve fine-mapping of causal variants for several loci. Integration of multiple lines of genetic evidence support the functional relevance of the identified POAG risk loci and highlight potential contributions of several genes to POAG pathogenesis, including SVEP1, RERE, VCAM1, ZNF638, CLIC5, SLC2A12, YAP1, MXRA5, and SMAD6. Several drug compounds targeting POAG risk genes may be potential glaucoma therapeutic candidates. Primary open-angle glaucoma (POAG) is highly heritable, yet not well understood from a genetic perspective. Here, the authors perform a meta-analysis of genome-wide association studies in 34,179 POAG cases, identifying 44 previously unreported risk loci and mapping effects across multiple ethnicities

    Mammalian response to global change in the later Quaternary of the British Isles

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    Comments On The Proposed Conservation Of Some Mammal Generic Names First Published In Brisson\u27s (1762) Regnum Animale

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    Volume: 52Start Page: 271End Page: 27

    The Mammal Faunas of the British Late Pleistocene

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    Symposium 2: User Perspectives on the Pedagogical Differences Between Electronic and Paper Portfolios

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    This paper reports on a formative examination of the pedagogical impact of e-portfolios recently introduced to postgraduate medical education at the Bradford NHS Trust and undergraduate/postgraduate healthcare training at the University of Leeds. Early results suggest that there are differences emerging in the learners' perceptions of the development of reflective skills, ownership of work and the ability to present evidence for assessment depending on whether the students are using a paper or electronic portfolio. Preliminary findings also suggest that to be successful, e-portfolios need to have support from the users and their supervisors/mentors who provide feedback. The paper will also highlight issues for further discussion and future investigation such as the nature of ownership, assessing reflective ability and learning, time issues, and feedback

    Symposium 2: Implementing e-Portfolios: Technical and Organisational Issues

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    Personal development planning (PDP) is a key issue in relation to professional and career development, and e-portfolios are a tool that can aid in this process. Many benefits of paper-based and online portfolios have been investigated but less has been reported on the technological and organisational issues which impact on user acceptance and uptake. This paper reports on experiences of the Enhancing Learner Progression Project in implementing two different e-portfolio systems in six different personal development contexts. Findings relate to access to the e-portfolio, the need for changes in pedagogy, time constraints for staff using e-portfolios and the future direction and questions raised from using e-portfolios

    A Middle Devensian woolly rhinoceros from Whitemoor Haye Quarry, Staffordshire (UK): palaeoenvironmental context and significance

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    This paper reports the discovery of a rare partial skeleton of a woolly rhinoceros (Coelodonta antiquitatis Blumenbach, 1799) and associated fauna from a low Pleistocene terrace of the River Tame at Whitemoor Haye, Staffordshire, UK. A study of the sedimentary deposits around the rhino skeleton and associated organic-rich clasts containing pollen, plant and arthropod remains suggests that the animal was rapidly buried on a braided river floodplain surrounded by a predominantly treeless, herb-rich grassland. Highlights of the study include the oldest British chironomid record published to date and novel analysis of the palaeoflow regime using caddisfly remains. For the first time, comparative calculations of coleopteran and chironomid palaeotemperatures have been made on the same samples, suggesting a mean July temperature of 8–11 8C and a mean December temperature of between -22 and -16 °C. Radiocarbon age estimates on skeletal material, supported by optically stimulated luminescence ages from surrounding sediments, indicate that the rhino lived around 41–43 k cal a BP. The combined geochronological, stratigraphic and palaeoenvironmental evidence places the assemblage firmly within the Middle Devensian (Marine Oxygen Isotope Stage 3). This would agree with other regional evidence for the timing of aggradation for the lowest terrace of the Trent and its tributary systems
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