532 research outputs found

    Impact of management regime and regime change on gravel barrier response to a major storm surge

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    Gravel barriers represent physiographic, hydrographic, sedimentary, and ecological boundaries between inshore and open marine offshore environments, where they provide numerous important functions. The morphosedimentary features of gravel barriers (e.g., steep, energy reflective form) have led to their characterization as effective coastal defense features during extreme hydrodynamic conditions. Consequently, gravel barriers have often been intensively managed to enhance coastal defense functions. The Blakeney Point Barrier System (BPBS), U.K., is one such example, which offers the opportunity to investigate the impact of alternative management regimes under extreme hydrodynamic conditions. The BPBS was actively re-profiled along its eastern section from the 1950s to the winter of 2005, whilst undergoing no active intervention along its western section. Combining an analysis of remotely sensed elevation datasets with numerical storm surge modeling, this paper finds that interventionist management introduces systemic differences in barrier morphological characteristics. Overly steepened barrier sections experience greater wave run-up extents during storm surge conditions, leading to more extreme morphological changes and landward barrier retreat. Furthermore, while high, steep barriers can be highly effective at preventing landward flooding, in cases where overwashing does occur, the resultant landward overtopping volume is typically higher than would be the case for a relatively lower crested barrier with a lower angled seaward slope. There is a growing preference within coastal risk management for less interventionist management regimes, incorporating natural processes. However, restoring natural processes does not immediately or inevitably result in a reduction in coastal risk. This paper contributes practical insights regarding the time taken for a previously managed barrier to relax to a more natural state, intermediary morphological states, and associated landward water flows during extreme events, all of which should be considered if gravel barriers are to be usefully integrated into broader risk management strategies.</jats:p

    A Bayesian network approach for coastal risk analysis and decision making

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    Emergency management and long-term planning in coastal areas depend on detailed assessments (meter scale) of flood and erosion risks. Typically, models of the risk chain are fragmented into smaller parts, because the physical processes involved are very complex and consequences can be diverse. We developed a Bayesian network (BN) approach to integrate the separate models. An important contribution is the learning algorithm for the BN. As input data, we used hindcast and synthetic extreme event scenarios, information on land use and vulnerability relationships (e.g., depth-damage curves). As part of the RISC-KIT (Resilience-Increasing Strategies for Coasts toolKIT) project, we successfully tested the approach and algorithm in a range of morphological settings. We also showed that it is possible to include hazards from different origins, such as marine and riverine sources. In this article, we describe the application to the town of Wells-next-the-Sea, Norfolk, UK, which is vulnerable to storm surges. For any storm input scenario, the BN estimated the percentage of affected receptors in different zones of the site by predicting their hazards and damages. As receptor types, we considered people, residential and commercial properties, and a saltmarsh ecosystem. Additionally, the BN displays the outcome of different disaster risk reduction (DRR) measures. Because the model integrates the entire risk chain with DRR measures and predicts in real-time, it is useful for decision support in risk management of coastal areas.European Community's 7th Framework Programme through the grant to RISC-KIT (Resilience-increasing Strategies for Coasts - Toolkit"), contract no. 603458

    Regional coastal flood risk assessment for a tidally dominant, natural coastal setting: North Norfolk, southern North Sea

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    A Coastal Risk Assessment Framework (CRAF) provides two levels of coastal risk and vulnerability assessment, by combining information on the spatially variable hazard and exposure. In Phase 1, areas of greatest risk or `hotspots' are identified. In Phase 2, these hotspots are then analysed in greater detail to identify both direct and indirect extreme event impacts. This approach was applied to the barrier coastline of North Norfolk, eastern England. The CRAF identified high risk coastal hotspots on the basis of both hazard impacts (swash regime (tide + surge + wave runup) and overwash/terrestrial inundation regimes) from a 1 in 115 year return period storm and a range of land use, infrastructure, economic and social vulnerability indicators. Hazard extents and hazard severity, in some locations modified by the presence of intertidal saltmarsh, were calculated for 45, 1-2 km wide sections along the topographically complex coast. When combined with five exposure indicators, eight hotspots were identified along the 45 km long frontage. In a 2nd phase, two of these hotspots, one a chain of small villages (Brancaster/Brancaster Staithe/Burnham Deepdale) and one a small town (Wells-next-the-Sea), were compared in more detail using a suite of coastal inundation and impact assessment models to determine both direct and indirect impacts. Hazards at this higher resolution were calculated using the 1D process-based XBeach model and the 2D LISFLOOD inundation model. Vulnerability to the hazards was calculated using the INDRA (Integrated Disruption Assessment) model with comparison of the two hotspots through the use of a Multi Criteria Analysis (MCA). The selection of hazard hotspots and comparison of hotspots using these techniques allows areas at greatest risk to be identified, of vital importance for coastal management and resource allocation.This work was supported by the European Community’s 7th Framework Programme through the grant to RISC-KIT (“Resilience-increasing Strategies for Coasts Toolkit”), contract no. 603458, and by contributions by the partner institutes and a grant from The Isaac Newton Trust, Trinity College, Cambridge

    Reef-building corals thrive within hot-acidified and deoxygenated waters

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    Coral reefs are deteriorating under climate change as oceans continue to warm and acidify and thermal anomalies grow in frequency and intensity. In vitro experiments are widely used to forecast reef-building coral health into the future, but often fail to account for the complex ecological and biogeochemical interactions that govern reefs. Consequently, observations from coral communities under naturally occurring extremes have become central for improved predictions of future reef form and function. Here, we present a semi-enclosed lagoon system in New Caledonia characterised by diel fluctuations of hot-deoxygenated water coupled with tidally driven persistently low pH, relative to neighbouring reefs. Coral communities within the lagoon system exhibited high richness (number of species = 20) and cover (24-35% across lagoon sites). Calcification rates for key species (Acropora formosa, Acropora pulchra, Coelastrea aspera and Porites lutea) for populations from the lagoon were equivalent to, or reduced by ca. 30-40% compared to those from the reef. Enhanced coral respiration, alongside high particulate organic content of the lagoon sediment, suggests acclimatisation to this trio of temperature, oxygen and pH changes through heterotrophic plasticity. This semi-enclosed lagoon therefore provides a novel system to understand coral acclimatisation to complex climatic scenarios and may serve as a reservoir of coral populations already resistant to extreme environmental conditions

    Endogenous antigen processing drives the primary CD4+ T cell response to influenza.

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    By convention, CD4+ T lymphocytes recognize foreign and self peptides derived from internalized antigens in combination with major histocompatibility complex class II molecules. Alternative pathways of epitope production have been identified, but their contributions to host defense have not been established. We show here in a mouse infection model that the CD4+ T cell response to influenza, critical for durable protection from the virus, is driven principally by unconventional processing of antigen synthesized within the infected antigen-presenting cell, not by classical processing of endocytosed virions or material from infected cells. Investigation of the cellular components involved, including the H2-M molecular chaperone, the proteasome and Îł-interferon-inducible lysosomal thiol reductase revealed considerable heterogeneity in the generation of individual epitopes, an arrangement that ensures peptide diversity and broad CD4+ T cell engagement. These results could fundamentally revise strategies for rational vaccine design and may lead to key insights into the induction of autoimmune and anti-tumor responses

    Cell Free Expression of hif1α and p21 in Maternal Peripheral Blood as a Marker for Preeclampsia and Fetal Growth Restriction

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    Preeclampsia, a severe unpredictable complication of pregnancy, occurs in 6% of pregnancies, usually in the second or third trimester. The specific etiology of preeclampsia remains unclear, although the pathophysiological hallmark of this condition appears to be an inadequate blood supply to the placenta. As a result of the impaired placental blood flow, intrauterine growth restriction (IUGR) and consequential fetal oxidative stress may occur. Consistent with this view, pregnancies complicated by preeclampsia and IUGR are characterized by up-regulation of key transcriptional regulators of the hypoxic response including, hif1α and as well as p53 and its target genes. Recently, the presence of circulating cell-free fetal RNA has been documented in maternal plasma. We speculated that pregnancies complicated by preeclampsia and IUGR, will be associated with an abnormal expression of p53 and/or hif1α related genes in the maternal plasma. Maternal plasma from 113 singleton pregnancies (72 normal and 41 complicated pregnancies) and 19 twins (9 normal and 10 complicated pregnancies) were collected and cell free RNA was extracted. The expression of 18 genes was measured by one step real-time RT-PCR and was analyzed for prevalence of positive/negative expression levels. Results indicate that, among the genes examined, cell free plasma expressions of p21 and hif1α were more prevalent in pregnancies complicated by hypoxia and/or IUGR (p<0.001). To conclude, we present in this manuscript data to support the association between two possible surrogate markers of hypoxia and common complications of pregnancy. More work is needed in order to implement these findings in clinical practice

    Affecting solidarities: bringing feeling into feminism, empathy in employment and compassion in academic communities of crises

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    While a wider context of crisis and neoliberal practices engulfing academia has triggered a variety of debilitating impacts on both education and academic working lives, tourism academia remains an insulated workplace, slowly responding to efforts corresponding to a politics of care, diversity and inclusivity. In highlighting attention to the issue of gender equity in tourism academia, this paper draws on netnographic analysis from one global electronic mailing list and analyses empirical data on the issues of ‘gender’, ‘women’ and ‘diversity’. The case study brings to the fore the urgency of addressing these issues as regards tourism academia. The latter is a space that we argue would benefit from enactments that nurture affectivities of solidarity. These are exemplified in the form of caring, compassionate and feeling fuelled inclusive workplaces. This paper aims to stimulate further debate in underscoring the need to introduce what we term ‘unbounded feminisms of solidarity and compassion’
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