965 research outputs found

    Can the mid-Holocene provide suitable models for rewilding the landscape in Britain?

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    Palaeoecologists have been encouraging us to think about the relevance of the Holocene fossil record for nature conservation for many years (e.g. Buckland 1993) but this information seems slow to filter through to the conservation community. Indeed, Willis et al. (2005) report that recently published biodiversity reports and policy documents rarely look back more than 50 years and may ignore the historical context entirely. This has been a lost opportunity for understanding ecological systems. Many natural processes occur over timescales that confound our attempts to understand them, so the vast temporal perspective provided by palaeoecological studies can provide important guidance for nature conservation (Willis & Birks 2006). However, accurate vegetation mapping is difficult enough in modern landscapes (Cherrill & McLean 1999), so the challenge of describing prehistoric environments is immeasurably greater. Nevertheless, pioneering work in the mid 20th century showed that pollen and spores extracted from peat bogs were so perfectly preserved thatthey could be used to demonstrate sequences of vegetation change since the last glaciation (Godwin 1956). Since then, the science has burgeoned: ancient deposits of beetles, snails, fungal spores and plant macrofossils add to the picture, as does the chemistry of ancient lake sediments (Bell & Walker 2004). Many questions still remain to be answered by this fascinating research and one aspect has received considerable attention in the last decade. This concerns the nature of the ‘primeval’ landscapes, in other words our understanding of natural systems prior to significant human impact. The debate was kindled by a thesis by the Dutch forest ecologist Frans Vera in 2000 (see also Vera & Buissink 2007). Vera effectively challenged established views about the primeval landscapes and argued that the refutation, and the resulting alternative landscape models, had critical importance for modern conservation practice. Vera’s thesis is focused on the pre-Neolithic (ca 8000-5000bp) landscape in the lowlands of central and western Europe, with the assumption that this period represents an almost pristine or ‘natural’ state which should provide a suitable conservation benchmark. Vera contends (i) that this landscape was not closed woodland but a relatively open park-like mosaic of wood and grassland,and (ii) that large wild herbivores were an essential driving force behind woodland-grassland vegetation cycles. The advocacy in his argument and the timing of the publication, when grazingwas seen as increasingly important in conservation in Europe, have combined to raise the profile of this issue. If Vera is correct, the open park-like landscapes were inherited rather than created by people; this may have implications for conservation practice in Europe. The adoption of Vera’s ideas into conservation management plans in the UK (see Box 1) gives an indication of the influence that this work has had. Indeed, Vera’s ideas have been described as a ‘challenge to orthodox thinking’ (Miller 2002) and considerable debate has been stimulated centering on the ecological validity of Vera’s hypothesis and its relevance for modern conservation. In this article, we attempt to address these issues on the basis of results from a literature review, web-debate and discussions with Dutch and British ecologists, prepared for English Nature with a view to informing conservation strategies (Hodder & Bullock 2005a)

    Aerodynamics of lift fan V/STOL aircraft

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    Aerodynamic characteristics of lift fan installation for direct lift V/STOL aircraf

    An investigation of engine influence on inlet performance

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    The performance of a conventional engine/inlet installation, in which inlet and engine flow field interaction occurs, was compared to the performance of the same inlet remote coupled to the engine. The remote coupled inlet configuration decouples the influence of the engine on the inlet flow field and simulates current small scale inlet test techniques in which inlet airflow is provided by a vacuum source or coupled engine. The investigation was conducted in the NASA-Ames 40- by 80-foot wind tunnel using a General Electric TF-34 turbofan engine and a subsonic inlet having an average inlet contraction ratio of 1.26. Test results indicated that engine interaction allows the inlet to operate with lower distortion levels at and beyond the separation angle-of-attack experienced without engine interaction

    Further studies of static to flight effects on fan tone noise using inlet distortion control for source identification

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    Current experimental investigations have linked static inflow distortion phenomena such as the ground vortex, atmospheric turbulence, and teststand structure interference to the generation of fan tone noise at the blade passing frequency. Since such distortions do not exist in flight, it is important to remove them from the static test environment and thereby improve the static-to-flight tone-noise correlation. In the course of providing evidence for this position, a recent investigation used a distortion control inlet with a modern day turbofan engine to assess atmospheric turbulence effects. Although the initial results were encouraging, they were incomplete. The present investigation continues this work and shows more completely the effect of atmospheric turbulence on tone-noise generation. Further, use is made of the distortion control inlet to identify other competing tone-noise sources in the test engine such as a rotor-core stator interaction which was confirmed by engine modifications

    Aerodynamic characteristics of a large-scale V/STOL transport model with tandem lift fans mounted at mid-semispan of the wing

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    Aerodynamic characteristics of V/STOL transport model with tandem lift fans mounted at mid-semispan of win

    Higher comfort temperature preferences for anthropometrically matched Chinese and Japanese versus White-Western-Middle-European individuals using a personal comfort / cooling system

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    Purpose: To investigate potential differences in preferred Personal Comfort Systems (PCS) settings of Japanese and Han-Chinese versus white-western-middle-Europeans. Method: A series of five experiments with similar methodology is reported that allowed participants to self-select their preferred PCS outlet air temperature in a warm controlled climatic chamber setup with and without solar radiation. Test groups were matched for age, height, weight, body-surface-area and body-mass-index to remove the influence of these confounding factors on the results. Participants were first exposed to solar radiation (exp-1-4; simulating glazed building without proper shading or a car) before starting to control the outlet temperature of the PCS, or (exp-5, simulating warm building) were exposed to a warm room temperature and immediately could control the PCS. Ethnicity effects were studied through the chosen preferred PCS outlet temperatures and the microclimate temperature close to the participants’ chest. Results: In all experiments, Asian groups selected a PCS outlet temperature significantly higher, on average by 5 °C, leading to a 1.9 °C higher microclimate temperature at chest level. While absolute selected temperatures of the PCS differed between experiments, related to different designs of the PCS and climate conditions, no interaction between ethnicity and experiment was present. Conclusions: Despite removing important confounding factors that could explain earlier observed differences between Asian and white western middle-European ethnicities tested, a substantial, consistently higher thermal preference temperature of the PCS was found in the two Asian groups. This has implications for the design parameters of PCS for use in offices or air-conditioning systems in cars

    Interventions in sports settings to reduce risky alcohol consumption and alcohol-related harm: a systematic review

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    Background: Elevated levels of risky alcohol consumption and alcohol-related harm have been reported for sportspeople and supporters compared to non-sporting populations. Limited systematic reviews have been conducted to assess the effect of interventions targeting such behaviours. Methods: A review was undertaken to determine if interventions implemented in sports settings decreased alcohol consumption and related harms. Studies were included that implemented interventions within sports settings; measured alcohol consumption or alcohol-related injury or violence and were either randomised controlled trials, staggered enrolment trials, stepped-wedged trials, quasi-randomised trials, quasi-experimental trials or natural experiments. Studies without a parallel comparison group were excluded. Studies from both published and grey literature were included. Two authors independently screened potential studies against the eligibility criteria, and two authors independently extracted data from included studies and assessed risk of bias. The results of included studies were synthesised narratively. Results: The title and abstract of 6382 papers and the full text of 45 of these papers were screened for eligibility. Three studies met the inclusion criteria for the review. One of the included studies was a randomised controlled trial (RCT) of a cognitive-behavioural intervention with athletes within an Olympic training facility in the USA. The study reported a significant change in alcohol use between pre-test and follow-up between intervention and control groups. The other two studies were RCTs in community sports clubs in Ireland and Australia. The Australian study found a significant intervention effect for both risky alcohol consumption at sports clubs and overall risk of alcohol-related harm. The Irish study found no significant intervention effect. Conclusions: A limited number of studies have been conducted to assess the effect of interventions implemented in sports settings on alcohol consumption and related harms. While two of the three studies found significant intervention effects, it is difficult to determine the extent to which such effects are generalisable. Further controlled trials are required in this setting. Systematic review registration: PROSPERO CRD4201400173

    Does landscape-scale conservation management enhance the provision of ecosystem services?

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    Biodiversity conservation approaches are increasingly being implemented at the landscape-scale to support the maintenance of metapopulations and metacommunities. However, the impact of such interventions on the provision of ecosystem services is less well defined. Here we examine the potential impacts of landscape-scale conservation initiatives on ecosystem services, through analysis of five case study areas in England and Wales. The provision of multiple ecosystem services was projected according to current management plans and compared with a baseline scenario. Multicriteria analysis indicated that in most cases landscape-scale approaches lead to an overall increase in service provision. Consistent increases were projected in carbon storage, recreation and aesthetic value, as well as biodiversity value. However, most study areas provided evidence of trade-offs, particularly between provisioning services and other types of service. Results differed markedly between study areas, highlighting the importance of local context. These results suggest that landscape-scale conservation approaches are likely to be effective in increasing ecosystem service provision, but also indicate that associated costs can be significant, particularly in lowland areas

    A thematic study of the role of social support in the body image of burn survivors

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    There is evidence that social support is important for the development and maintenance of body image satisfaction for people who have sustained burn injuries. This qualitative study explored the specific mechanisms by which social support impacts the body image satisfaction of burn survivors, drawing on nine participants' in depth accounts. Participants were recruited through a burns unit at a public hospital in South Australia. Interviews were conducted with nine female burn survivors aged between 24 and 65 (mean age 44.6). Participants described their perceptions about their appearance post burn and their social support experiences. Four themes were identified: acceptance, social comparison, talking about appearance concerns, and the gaze of others. Results indicate that for these participants, social support was an important factor in coming to terms with changes in appearance, specifically support that helps to minimise feelings of difference. Unhelpful aspects of social support were also identified included feeling that suffering was being dismissed and resenting the perceived expectation from supports to be positive. Social supports are important to consider in relation to body image for those working with people who have survived burn injuries.Kellie Hodder, Anna Chur-Hansen, Andrea Parke
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