132 research outputs found

    Later prehistoric woodlands and wood use on the lower Thames floodplain

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    The thesis seeks to illuminate the character of later prehistoric woodlands on the Thames floodplain and their use by contemporary communities. This is achieved by the application of a two-pronged research agenda which examines both non-cultural and cultural waterlogged wood assemblages from east London. The non-cultural data is obtained from the mapping, recording and species identification of 1679 tree trunks, stumps and root systems preserved on the Thames foreshore at Erith in Kent. This research facilitates the characterisation of four temporally distinct woodlands dating from the Later Neolithic through to the Early Iron Age period. Application of ecological and forest stand dynamics models provides a detailed reconstruction of the prehistoric landscape including the species composition, density, canopy height and maturity of the floodplain woodlands. As such, the three-dimensional woodland reconstructions provide the tangible character of the wooded landscape within which prehistoric activity is contextualised. Bronze Age trackway assemblages from Beckton Nursery in Newham and the Thames foreshore at Erith are simultaneously examined. Morphological and tree-ring analysis illuminates the nature of prehistoric wood use on the Thames floodplain, including evidence for tree species selection, woodland management and various woodworking techniques. This information is then placed within the reconstructed wooded landscape to facilitate comparison of the two datasets. It is suggested that the targeting of specific timber resources on the floodplain and the introduction of woodland management regimes linked to animal husbandry characterised woodland use. Furthermore, the contextualisation of the trackway features within the reconstructed landscape enables wider suggestions pertaining to contemporary cultural perceptions of the wooded landscape and alternative interpretations of later prehistoric activity on the floodplain

    Bet- hedging reproduction strategies in the massive Caribbean coral Favia fragum

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    Bet- hedging has long been recognised as an adaptive mechanism in unpredictable environments, yet is often overlooked as an evolutionary strategy in corals to adapt to environmental conditions associated with climate change. Most environments vary spatially and temporally over the lifespan of corals, and corals use cues from their natal environments as “predictors” of the environment they will release their offspring into and may optimise phenotypes to maximise fitness to changes in the maternal environment. However, when conditions fluctuate in unpredictably or environmental cues are otherwise lost, producing a single phenotype could cause population bottlenecks. Prolonged summer periods of high sea surface temperatures combined with anthropogenic impacts are inhibiting environmental cues that have previously secured reproductive success in tropical scleractinian corals and enabled them to fine-tune their reproductive patterns to time periods that optimize external fertilization success, appropriate larval dispersal and efficient coral recruitment. This study tested the ability of the brooding species Favia fragum to “hedge their bets” on reproductive strategies in the presence/ absence of lunar cues, a cue known to play an important role in synchronizing reproductive output. Results illustrated F. fragum exhibited dynamic bet-hedging, tailoring larval output and producing a range of larval phenotypes and thus exhibiting plasticity dependent on their environment. In the absence of lunar cues, corals varied the timing of planulae release as well as within-clutch size variation promoting dispersal and retention to their natal environment. Lunar stimulated corals concentrated release to 3-6 days, typically produced a single phenotype aiding retention and re-seeding local reef populations. Reproductive flexibility will enable coral to strategize larval/ gamete release that optimise recruitment success within unstable environmental conditions. The use of such strategies in other brooding species and broadcast spawners should be a focus of further investigation to evaluate the potential for corals to populate environments beyond the familiar and persist future unpredictabilit

    Early emergence of CD19-negative human antibody secreting cells at the plasmablast to plasma cell transition

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    Long-lived human plasma cells (PCs) play central roles in immunity and autoimmunity and are enriched amongst the subpopulation of CD19-negative human PCs. However, whether human CD19-negative PCs are necessarily ″aged″ cells that have gradually lost CD19 expression is not known. Assessing peripheral blood samples at steady state and during the acute response to influenza vaccination in healthy donors we identify the presence of phenotypic CD19-negative plasmablasts, the proliferative precursor state to mature PCs, and demonstrate by ELISpot that these are antibody-secreting cells (ASCs). During the acute response to influenza vaccination CD19-positive, CD19-low and CD19-negative ASCs secrete vaccine-specific antibody and show linked IGHV repertoires. To address precursor/product relationships we employ in vitro models which mimic both T-dependent and T-independent differentiation finding that the CD19-negative state can be established at the plasmablast to PC transition, that CD19-negative PCs increase as a percentage of surviving PCs in vitro, and that CD19-negative and CD19-positive PCs can be maintained independently. These data provide proof-of-principle for the view that newly generated ASCs can acquire a mature PC phenotype accompanied by loss of CD19 expression at an early stage of differentiation and that ″aging″ is not an obligate requirement for a CD19-negative state to be established

    Network analysis identifies proinflammatory plasma cell polarization for secretion of ISG15 in human autoimmunity

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    Plasma cells (PCs) as effectors of humoral immunity produce Igs to match pathogenic insult. Emerging data suggest more diverse roles exist for PCs as regulators of immune and inflammatory responses via secretion of factors other than Igs. The extent to which such responses are preprogrammed in B-lineage cells or can be induced in PCs by the microenvironment is unknown. In this study, we dissect the impact of IFNs on the regulatory networks of human PCs. We show that core PC programs are unaffected, whereas PCs respond to IFNs with distinctive transcriptional responses. The IFN-stimulated gene 15 (ISG15) system emerges as a major transcriptional output induced in a sustained fashion by IFN-α in PCs and linked both to intracellular conjugation and ISG15 secretion. This leads to the identification of ISG15-secreting plasmablasts/PCs in patients with active systemic lupus erythematosus. Thus, ISG15-secreting PCs represent a distinct proinflammatory PC subset providing an Ig-independent mechanism of PC action in human autoimmunity

    Addressing marine and coastal governance conflicts at the interface of multiple sectors and jurisdictions

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    Marine and coastal activities are closely interrelated, and conflicts among different sectors can undermine management and conservation objectives. Governance systems for fisheries, power generation, irrigation, aquaculture, marine biodiversity conservation, and other coastal and maritime activities are typically organized to manage conflicts within sectors, rather than across them. Based on the discussions around eight case studies presented at a workshop held in Brest in June 2019, this paper explores institutional approaches to move beyond managing conflicts within a sector. We primarily focus on cases where the groups and sectors involved are heterogeneous in terms of: the jurisdiction they fall under; their objectives; and the way they value ecosystem services. The paper first presents a synthesis of frameworks for understanding and managing cross-sectoral governance conflicts, drawing from social and natural sciences. We highlight commonalities but also conceptual differences across disciplines to address these issues. We then propose a novel analytical framework which we used to evaluate the eight case studies. Based on the main lessons learned from case studies, we then discuss the feasibility and key determinants of stakeholder collaboration as well as compensation and incentive schemes. The discussion concludes with future research needs to support policy development and inform integrated institutional regimes that consider the diversity of stakeholder interests and the potential benefits of cross-sectoral coordination

    Community Development for Adaptation

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    Council-community engagement for a climate-impacted future – research brief. Many of New Zealand’s urban settlements are likely to be impacted by climate-induced hazards such as coastal erosion, flooding and rising groundwater levels. Affected communities will face physical, social, financial and emotional challenges. To ensure successful adaptation, local authorities will need to adopt new approaches to engagement with communities that are exposed to these hazards. This summary forms part of the research findings of the Climate-Adaptive Communities project of the Deep South National Science Challenge. We have drawn from the stories and insights shared with the research team by community members, iwi members and council staff

    Extensive study of HD 25558, a long-period double-lined binary with two SPB components

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    We carried out an extensive observational study of the Slowly Pulsating B (SPB) star, HD 25558. The ≈2000 spectra obtained at different observatories, the ground-based and MOST satellite light curves revealed that this object is a double-lined spectroscopic binary with an orbital period of about nine years. The observations do not allow the inference of an orbital solution. We determined the physical parameters of the components, and found that both lie within the SPB instability strip. Accordingly, both show line-profile variations due to stellar pulsations. 11 independent frequencies were identified in the data. All the frequencies were attributed to one of the two components based on pixel-by-pixel variability analysis of the line profiles. Spectroscopic and photometric mode identification was also performed for the frequencies of both stars. These results suggest that the inclination and rotation of the two components are rather different. The primary is a slow rotator with ≈6 d period, seen at ≈60° inclination, while the secondary rotates fast with ≈1.2 d period, and is seen at ≈20° inclination. Spectropolarimetric measurements revealed that the secondary component has a magnetic field with at least a few hundred Gauss strength, while no magnetic field can be detected in the primary
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