Gravel Barrier Beach Morphodynamic Response to Storm Events

Gravel beaches and barriers form a valuable natural protection for many shorelines. Gravel beach response to waves has been studied extensively, for regular and irregular waves, but there is little reported investigation of beach response to bimodal wave conditions, quite commonly experienced at midlatitudes. The paper presents a numerical modelling study of gravel barrier beach response to storm wave conditions. The XBeach non-hydrostatic model was set up in 1D mode to investigate barrier volume change and overwash under a wide range of unimodal and bimodal storm conditions and barrier cross sections. The numerical model was validated against conditions at Hurst Castle Spit, UK. The validated model is used to simulate the response of a range of gravel barrier cross sections under a wide selection of statistically significant storm wave and water level scenarios thus simulating an ensemble of realisations of barrier volume change and overwash. This ensemble of results was used to develop a simple parametric model for estimating barrier volume change during a given storm and water level condition. Attempts were also made to model overwash and crest changes of barriers, however further study Is required. Numerical simulations of barrier response to bimodal storm conditions, which are a common occurrence in many parts of the UK, reveals that barrier volume change and overwash from bimodal storms will be higher than that from unimodal storms if the swell percentage is greater than 40%. The limitations of the modelling approach and the model results are noted. The model is demonstrated as providing a useful tool for estimating barrier volume change, a commonly used measure used in gravel barrier beach management

Mapping the development of professional praxis of Higher Education work-based learners via a case-study approach

This study explores ways in which sixteen mature learners develop their professional praxis through participation in a Higher Education work-based learning (HEWBL) programme. It examines the theoretical underpinnings of work based learning (WBL) emphasising the role reflection plays in developing learners’ professional praxis. Outcomes indicate how learners’ engagement can be mapped, suggesting a typology that may support future HEWBL developments. UK-based HEWBL has expanded significantly since the 1980s in response to Government pressure, as a means of meeting demand for higher-level skills necessary to compete globally. Higher Education Institutions (HEIs) play a crucial role in providing effective workforce development opportunities through HEWBL, as these widen participation and develop and support employees becoming self-managing professionals and autonomous learners. Reflective learning is central to many HEWBL programmes aiming to develop professional praxis, yet its efficacy as a pedagogical strategy is contested. This thesis provides empirical evidence for praxis development through reflective learning, thus illuminating its effectiveness as a pedagogical strategy. The study adopted a multiple-case study approach. The sixteen learners were primarily public sector employees aged over 25, engaged in professional roles. As such, participants were under-taking HEWBL voluntarily to promote their career prospects. Detailed accounts of learners’ WBL experiences were obtained via analysis of semi-structured interviews, completed novel reflective learning templates and essays. The thesis reports that learners develop professional praxis in four learning domains, namely affective, lifelong, professional and organizational. The study established a method for mapping praxis across each domain, thus making each observable. Scoring “strength” of evidence for each domain generated maps that enable identification of two distinct learner groups: one comprises predominantly lifelong and the second predominantly affective learners. This finding implies HEWBL generates contrasting outcomes for learners, and, in turn, suggests that planning HEWBL may be improved by taking these into consideration

Gravel Barrier Beach Morphodynamic Response to Extreme Conditions

Gravel beaches and barriers form a valuable natural protection for many shorelines. The paper presents a numerical modelling study of gravel barrier beach response to storm wave condi-tions. The XBeach non-hydrostatic model was set up in 1D mode to investigate barrier volume change and overwash under a wide range of unimodal and bimodal storm conditions and barrier cross sections. The numerical model was validated against conditions at Hurst Castle Spit, UK. The validated model is used to simulate the response of a range of gravel barrier cross sections under a wide selection of statistically significant storm wave and water level scenarios thus simulating an ensemble of barrier volume change and overwash. This ensemble of results was used to develop a simple parametric model for estimating barrier volume change during a given storm and water level condition under unimodal storm conditions. Numerical simulations of barrier response to bimodal storm conditions, which are a common occurrence in many parts of the UK were also investigated. It was found that barrier volume change and overwash from bimodal storms will be higher than that from unimodal storms if the swell percentage in the bimodal spectrum is greater than 40%. The model is demonstrated as providing a useful tool for estimating barrier volume change, a commonly used measure used in gravel barrier beach management

Metabolic programming of a beige adipocyte phenotype by genistein

Scope Promoting the development of brown or beige adipose tissue may protect against obesity and related metabolic features, and potentially underlies protective effects of genistein in mice. Methods and results We observed that application of genistein to 3T3-L1 adipocytes changed the lipid distribution from large droplets to a multilocular distribution, reduced mRNAs indicative of white adipocytes (ACC, Fasn, Fabp4, HSL, chemerin, and resistin) and increased mRNAs that are a characteristic feature of brown/beige adipocytes (CD-137 and UCP1). Transcripts with a role in adipocyte differentiation (Cebpβ, Pgc1α, Sirt1) peaked at different times after application of genistein. These responses were not affected by the estrogen receptor (ER) antagonist fulvestrant, revealing that this action of genistein is not through the classical ER pathway. The Sirt1 inhibitor Ex-527 curtailed the genistein-mediated increase in UCP1 and Cebpβ mRNA, revealing a role for Sirt1 in mediating the effect. Baseline oxygen consumption and the proportional contribution of proton leak to maximal respiratory capacity was greater for cells exposed to genistein, demonstrating greater mitochondrial uncoupling. Conclusions We conclude that genistein acts directly on adipocytes or on adipocyte progenitor cells to programme the cells metabolically to adopt features of beige adipocytes. Thus, this natural dietary agent may protect against obesity and related metabolic disease

Gaussian process regression approach for predicting wave attenuation through rigid vegetation

Numerical modelling in the coastal environment often requires highly skilled users and can be hindered by high computation costs and time requirements. Machine Learning (ML) techniques have the potential to overcome these limitations and complement existing methods. This is an exploratory investigation utilising a Gaussian Process (GP) data-driven modelling approach that can reproduce, for the given range of conditions in this study, the results of a widely used process-based model, XBeachX, when applied to the challenging problem of wave attenuation through vegetation. This study utilises efficient sampling strategies for data exploration, providing a valuable framework for future studies. The GP model was trained on a synthetic dataset generated using the numerical model XBeachX, which was calibrated using laboratory measurements. Our findings indicate that well-trained ML models can strongly complement traditional modelling approaches, especially in an environment where data sources are increasingly available. We have also explored the underlying interactions of the GP model's input features and their relationship to the model's output through a sensitivity analysis

The Essential Interactions in Oxides and Spectral Weight Transfer in Doped Manganites

We calculate the value of the Fr\"ohlich electron-phonon interaction in manganites, cuprates, and some other charge-transfer insulators and show that this interaction is much stronger than any relevant magnetic interaction. A polaron shift due to the Fr\"ohlich interaction, which is about 1 eV, suggests that carriers in those systems are small (bi)polarons at all temperatures and doping levels, in agreement with the oxygen isotope effect and other data. An opposite conclusion, recently suggested in the literature, is shown to be incorrect. The frequency and temperature dependence of the optical conductivity of ferromagnetic manganites is explained within the framework of the bipolaron theory.Comment: 6 pages, REVTeX 3.1 with 3 eps-figures. Journal versio

Submerged and Emerged Rigid Vegetation Impact on Bedforms and Sediment Suspension under Wave Action

A series of experiments were carried out in a laboratory wave flume to investigate the impact of coastal rigid vegetation on suspended sediment transport and the generation of bedforms for a range of wave conditions for both submerged and emerged vegetations. Rigid arrays of cylindrical wooden dowels were used as vegetation mimics on a sandy bed. Two vegetation densities were selected, representing dense and sparse vegetation meadows. Synchronised flow velocity and suspended sediment concentration measurements were performed using particle image velocimetry and an acoustic backscatter sensor. Seabed ripples were observed in all cases where the near-bed velocity exceeded the threshold of sediment motion. The near-bed velocity governed sediment suspension on both bare and vegetated sediment seabeds. Near-bed sediment concentration on densely vegetated seabeds was lower than that of bare seabeds under the same wave conditions. These observations highlight the importance of considering the role of vegetation in shaping seabed morphology and the resultant suspended sediment concentrations. Then, the near-bed sediment concentration formulae used on bare sediment beds are validated for use on vegetated seabeds

An investigation of roles for SIRT1 and dietary polyphenols in modulating the ageing process through DNA methylation

Dietary restriction (DR) can increase lifespan across evolutionarily distinct species, from yeast to rodents. The NAD+-dependent (class III) histone deacetylase SIRT1 in mammals, and its ortholog in other species, may play a major role in this response, but may affect ‘healthspan’ (number of years of good health), rather than lifespan per se. Ageing is accompanied by changes in genome methylation, which may be causal in the ageing process. Since histones are one of the many substrates that are deacetylated by SIRT1, we hypothesised that epigenetic effects of SIRT1 activity – and specifically effects on DNA methylation, which is associated closely with histone acetylation – mediate some of the beneficial effects of DR that contribute to increased healthspan. We also propose that dietary polyphenols may act at the cellular level in a similar way. To test this hypothesis, we first investigated effects of altering SIRT1 expression, by overexpression of a transgene or siRNA-mediated knockdown, on global DNA methylation (methylation of the LINE-1 element) in the human intestinal cell line, Caco-2. We also measured effects on global DNA methylation of dietary isoflavones and resveratrol, under control conditions as well as conditions of SIRT1 overexpression. Measured effects on global DNA methylation revealed possible complex interactions between SIRT1 and these dietary polyphenols but were dependent on the assay used to measure methylation at the LINE-1 element (COBRA or pyrosequencing), so were not considered to be robust observations. We investigated factors that may affect SIRT1 expression – specifically we examined SIRT1 promoter activity in response to polyphenols, effects of promoter methylation and effects of age. Treatment of Caco-2 cells with dietary polyphenols had no effect on the SIRT1 promoter in a promoter-reporter construct. In contrast, methylation of the SIRT1 promoter reduced reporter gene expression in this model. Age did not appear to change the levels of SIRT1 protein expressed in mouse intestinal tissue when comparing young and older mice. An in silico analysis was carried out to investigate if overlaps between groups of genes compiled from published and publically-available data found to i) associate with SIRT1, ii) show altered expression in response to DR, and iii) show altered methylation with ageing were greater than expected by chance, which would support the hypothesis, and provided targets to investigate possible site-specific effects of SIRT1 on DNA methylation. Ten genes were found to fit into the ‘three way’ overlap, which was statistically greater than expected by chance. Pyrosequencing assays could be optimised for only 8 of these 10 genes, so we focused further investigations on this sub-set. Significant effects of SIRT1 overexpression and/or knockdown on methylation were observed on at least one CpG site in the promoters of six of these genes (CDC7, EIF5, IRX3, KLF3, PTPRG, TBX3) and expression at the mRNA level of all of the eight genes (also PCYT1A and SLC39A4) was affected significantly. To gain a more comprehensive view of the extent to which DNA methylation at specific loci may be affected by SIRT1 expression levels microarray-based analysis of the methylation pattern across the genome in Caco-2 cells was carried out under conditions where SIRT1 was overexpressed or where expression was reduced by siRNA. In parallel, we measured the response to expressing SIRT1 at different levels at the level of the transcriptome. Overlaps that were statistically greater than expected by chance between these data and the lists of genes compiled from published and publically-available data used for the in silico analysis were found to exist between the complied list of genes reported to respond to dietary restriction and the set of genes we found to show altered expression in response to changing the level of SIRT1 expression and the set of genes we found to be differentially-methylated in response to reducing the level of SIRT1 expression. This observation is in broad support of our overarching hypothesis. The findings of this study indicate that effects of SIRT1 on methylation of specific genes may correspond with altered expression under conditions of dietary restriction. The data reveal a large number of gene targets for which causal links between these modifications roles in modulating the ageing process could be investigated.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Surprisingly poor correlation among pain scores prior to total hip arthroplasty

Pain is the main indication for total hip arthroplasty but is a subjective experience and can therefore be difficult to assess. Using completed forms from six hundred consecutive patients who were to undergo a total hip arthroplasty, we investigated the level of correlation between three widely used pain rating scales. These are: visual analogue pain scale, Merle d’Aubigne pain score and the first question on the Oxford Hip Score. We demonstrate here that there is a surprisingly poor correlation between the scores obtained from the three rating scales, albeit statistically significant. The use of more than one of the above pain scores is indicated due to the slightly different ways in which they ask the patients about their pain experience. This undoubtedly contributes to the modest correlation levels observed. Drawing extensive conclusions from a single pain rating scale may have significant clinical implications

A computational study of grid erosion through ion impact

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77047/1/AIAA-2000-3664-398.pd