378 research outputs found

    Macroinvertebrates, Heavy Metals and PAHs in Urban Watercourses

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    Good quality stream water and sediments are crucial for the support of healthy stream flora and fauna but urban runoff degrades watercourses leaving a legacy of pollution in the stream sediments. The sediment pollution load influences the development of macroinvertebrates which, as the lowest member of the food chain, influences the whole ecological structure. This review focuses on defining the sources and impacts of zinc, nickel, copper and oil derivative polycyclic aromatic hydrocarbon (PAH) contaminants in urban runoff. The impact of pollutants as measured by laboratory, field and modelling procedures are considered. Land use, position and connectivity of the runoff and sediment are seen to have an effect on the ecological integrity of the watercourse but case examples are sparse. The literature indicates that while reduced species diversity has been identified at a number of sites the dynamics are not well understood nor well modelled. These results are compared with field evidence from a study of 62 headwater streams with urban industrial and motorway land uses. From the review and field results it is evident that there is still an important need for process-based field measurements of urban water quality parameters. Forecasting the ecological status of watercourses would seem to benefit from data on sediment chemistry that considers the interaction effects of metals and PAHs

    A Cross-cohort Description of Young Peopleā€™s Housing Experience in Britain over 30 Years: An Application of Sequence Analysis

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    Methods. Sequence Analysis supported by Event History Analysis. Key Findings. Despite only 12 years separating both cohorts, the younger 1970 cohort exhibited very different patterns of housing including a slower progression out of the parental home and into stable tenure, and an increased reliance on privately rented housing. Returns to the parental home occurred across the twenties and into the thirties in both cohorts, although occurred more frequently and were more concentrated among certain groups in the 1970 cohort compared to the 1958 cohort. Although fewer cohort members in the 1970 cohort experienced social housing, and did so at a later age, social housing was also associated with greater tenure immobility in this younger cohort. Conclusions. The housing experiences of the younger cohort became associated with more unstable tenure (privately rented housing) for the majority. Leaving the parental home was observed to be a process, as opposed to a one-off event, and several returns to the parental home were documented, more so for the 1970 cohort. These findings are not unrelated, and in the current environment of rising house prices, collapses in the (youth) labour market and rising costs of higher education, are likely to increase in prevalence across subsequent cohorts

    Investigating the influence of heavy metals on macro-invertebrate assemblages using Partial Cononical Correspondence Analysis (pCCA)

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    International audienceThis paper defines the spectrum of impairment to stream macroinvertebrates arising from urban runoff. Field sampling of stream sediments at 62 sites across Yorkshire, UK was used to investigate the influence of heavy metals and habitat on macroinvertebrate family distribution using partial Canonical Correspondence Analysis (pCCA). Increasing urbanization and trafficking was associated with increasing levels of metal pollution but, even when traffic is light, family numbers can be reduced by 50%. Industrial areas and motorway runoff depress macroinvertebrate numbers but drainage from streets with no off-road parking in residential areas can have similar impacts. The heavy metals in the sediment accounted for approximately 24% of the variation in macroinvertebrate community composition while the physical habitat variables used in RIVPACS (River InVertebrate Prediction And Classification System) (Wright, 2000) accounted for an additional 30%. Zinc and nickel were the main metal influences regardless of the time of sampling; at these sites copper is less than critical. Results agree with those reported in other studies in which families mainly from the orders Ephemeroptera (mayfly), Plecoptera (stonefly) and Tricoptera (caddisfly) displayed metal sensitivity in that they were absent from metal polluted streams. However, within each of these orders, a continuum of sensitivity is evident: this highlights the risks of generalising on orders rather than using family or indeed species data. Keywords: macroinvertebrates, heavy metals, urban streams, tolerance, sensitivit

    Developing students as researchers ā€“ itā€™s all a muddle

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    Prof Pauline Kneale, Director, The Higher Education Academy Subject Centre for Geography, Earth and Environmental Science

    ā€˜But Iā€™ve been teaching for 20 yearsā€¦ā€™: encouraging teaching accreditation for experienced staff working in higher education

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    The status of teaching and learning is an issue those providing and supporting higher education grapple with. The UK Higher Education Academy offers accreditation aligned to the professional standards framework (PSF). The PSF contextualises the role of teaching and supporting learning, and offers a mechanism for individualsā€™ commitment to be recognised. Here, we present a case-study of 19 established academics who reflected on their experiences of gaining recognition through their universityā€™s accreditation scheme. Respondents prioritised institutional structures and outcomes such as student recruitment, job security, and status as drivers for engagement. Institutional leadership was significant in driving the accreditation agenda

    Strength in diversity: enhancing learning in vocationally-orientated, master's level courses

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    Postgraduate education in geography, especially at the Masterā€™s level, is undergoing significant changes in the developed world. There is an expansion of vocationally-oriented degree programmes, increasing recruitment of international students, integration of work place skills, and the engagement of non-traditional postgraduate students as departments respond to policies for a more ā€˜inclusiveā€™ higher education. This paper sets the context by outlining some programmatic changes in selected countries (Australia, the UK, and the USA). We briefly reflect on how postgraduate ā€˜barsā€™ or ā€˜levelsā€™ are defined and explore in detail what ā€˜diversityā€™ or ā€˜heterogeneityā€™ means in these new postgraduate settings. The paper then explores some examples of practice drawn from our own experiences, whilst recognising that relevance will vary in other contexts. Finally we consider how diversity can be harnessed as a strength that has potential to enhance taught elements of contemporary postgraduate education in and beyond the discipline

    DNA structural deformations in the interaction of the controller protein C.AhdI with its operator sequence

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    Controller proteins such as C.AhdI regulate the expression of bacterial restrictionā€“modification genes, and ensure that methylation of the host DNA precedes restriction by delaying transcription of the endonuclease. The operator DNA sequence to which C.AhdI binds consists of two adjacent binding sites, OL and OR. Binding of C.AhdI to OL and to OLā€‰+ā€‰OR has been investigated by circular permutation DNA-bending assays and by circular dichroism (CD) spectroscopy. CD indicates considerable distortion to the DNA when bound by C.AhdI. Binding to one or two sites to form dimeric and tetrameric complexes increases the CD signal at 278ā€‰nm by 40 and 80% respectively, showing identical local distortion at both sites. In contrast, DNA-bending assays gave similar bend angles for both dimeric and tetrameric complexes (47 and 38Ā°, respectively). The relative orientation of C.AhdI dimers in the tetrameric complex and the structural role of the conserved Py-A-T sequences found at the centre of C-protein-binding sites are discussed

    Easing the transition of First Year Undergraduates Through an Immersive Induction Module

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    Entry into higher education (HE) is recognised as a challenging time for undergraduates as they negotiate the norms and practices of new academic communities and foster relationships with peers and academics. Given the significance of this time period, our University has piloted a new four-week module that immerses students in their discipline and provides them with the academic skills and networks to support them through this period and beyond. Here we report a comprehensive evaluation examining academic and student experience of this immersive module. We explore its impact on essential aspects of the transition experience e.g. social integration, academic literacies and the sense of preparation for HE. Whilst this new approach did have positive impacts on studentsā€™ sense of integration, questions were raised around the extent to which it matched or even raised expectations, and the extent to which this prepared students for the rest of their studies

    DNA structural deformations in the interaction of the controller protein C.AhdI with its operator sequence

    Get PDF
    Controller proteins such as C.AhdI regulate the expression of bacterial restrictionā€“modification genes, and ensure that methylation of the host DNA precedes restriction by delaying transcription of the endonuclease. The operator DNA sequence to which C.AhdI binds consists of two adjacent binding sites, OL and OR. Binding of C.AhdI to OL and to OLā€‰+ā€‰OR has been investigated by circular permutation DNA-bending assays and by circular dichroism (CD) spectroscopy. CD indicates considerable distortion to the DNA when bound by C.AhdI. Binding to one or two sites to form dimeric and tetrameric complexes increases the CD signal at 278ā€‰nm by 40 and 80% respectively, showing identical local distortion at both sites. In contrast, DNA-bending assays gave similar bend angles for both dimeric and tetrameric complexes (47 and 38Ā°, respectively). The relative orientation of C.AhdI dimers in the tetrameric complex and the structural role of the conserved Py-A-T sequences found at the centre of C-protein-binding sites are discussed
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