985 research outputs found

    Alternative objectives : time extensions and less stringent objectives

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    The Water Framework Directive (2000/60/EC) (WFD) establishes a suite of environmental objectives for groundwater. In implementing the Directive and producing the first River Basin Management Plans, Member States have had to identify whether the these objectives are being met. If this assessment has shown that one or more of the objectives for groundwater is not being met, or is at risk of being failed, programmes of measures must be implemented to ensure that all relevant environmental objectives are met within six years – the publication date of the next River Basin Management Plan (22nd December, 2015). In reality, especially for groundwater, achieving all the relevant objectives in such a short timescale may not be possible or practical. The WFD recognises this and allows for an extension of the deadline (beyond 2015) for the purposes of a phased achievement of the environmental objectives. This is provided that there is no further deterioration in status (Article 4.4). Any such extension is limited to a maximum of two further river basin cycles (12 years) except where natural conditions mean that objectives can still not be achieved. A further provision is made for the situation where a water body is so badly affected by human activity or where natural conditions mean that achievement of the objectives(s) would be infeasible or disproportionally expensive. In these cases less stringent objectives (relative to those defined in Article 4.1) can be set, provided that there is the least possible deviation from good status conditions. Where extended deadlines or less stringent objectives have been proposed, Member States must provide an explanation and justification in the River Basin Management Plan. In the case of extended deadlines, a timetable for implementation of measures and the achievement of objectives must also be provided. This paper provides an overview of the approach used in England and Wales for identifying programmes of measures for groundwater, predicting outcomes and setting alternative objectives in relation to groundwater quality. Similar approaches were used for quantitative (water resource) aspects and also for surface water bodies

    The Nitrate Time Bomb (NTB) Model: a simple but effective method to investigate the impacts of historical nitrate loading on long-term groundwater nitrate concentrations

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    Nitrate water pollution, which remains an international problem, can cause long-term environmental damage and threaten both the economy and human health. Agricultural land is the major source of nitrate water pollution. It can take decades for nitrate leached from the soil to discharge into freshwaters. However, this nitrate time lag in the groundwater system has generally been ignored within the water resource management in many countries including the UK. We present a nitrate time bomb (NTB) model to modelling nitrate processes in the groundwater system. Whilst NTB contains simplified conceptual models, it can represent the major nitrate and hydrogeological processes in the groundwater system at both national and catchment scales, such as spatio-temporal nitrate loading, low-permeability superficial deposits, dual-porosity unsaturated zones and nitrate dilution in aquifers. The NTB model has been successfully used to simulate annual nitrate concentrations from 1925 to 2150 in the major aquifers in Great Britain and four local aquifer zones in the Eden Catchment, England. Monte Carlo simulations were undertaken to analyse parameter sensitivity and calibrate the model using observed datasets. These results help decision makers to understand how the historical nitrate loading from agricultural land affects the evolution of groundwater quality due to the nitrate time lag in the groundwater system. This NTB approach will be particularly valuable to evaluate the long-term impact and timescale of land management scenarios and programmes of measures introduced to help deliver water quality compliance. This model requires relatively modest parameterisation and is readily transferable to other areas

    Introduction to 'groundwater for Wellness'

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    The ground b elow our feet acts as a vast store of water, nearly 30% of all freshwater resources on earth are found underground . This ‘groundwater ’ exists in the pores between grains of rock or soil, within fractures in the rock , or even in large cave systems . Groundwater originates as rainfall or snowmelt that soaks into the ground continuing downwards , under the influence of gravity , until it reaches a zone in which all the available spaces are saturated with water – the top of this zone is called the water table. The level of the water tab le varies across different terrains, climates and rock types, and over time. Rocks that store and transmit important quantities of ground water and provide critical resources are called aquifers

    Integrating Dynamics and Wear Modelling to Predict Railway Wheel Profile Evolution

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    The aim of the work described was to predict wheel profile evolution by integrating multi-body dynamics simulations of a wheelset with a wear model. The wear modelling approach is based on a wear index commonly used in rail wear predictions. This assumes wear is proportional to Tγ, where T is tractive force and γ is slip at the wheel/rail interface. Twin disc testing of rail and wheel materials was carried out to generate wear coefficients for use in the model. The modelling code is interfaced with ADAMS/Rail, which produces multi-body dynamics simulations of a railway wheelset and contact conditions at the wheel/rail interface. Simplified theory of rolling contact is used to discretise the contact patches produced by ADAMS/Rail and calculate traction and slip within each. The wear model combines the simplified theory of rolling contact, ADAMS/Rail output and the wear coefficients to predict the wear and hence the change of wheel profile for given track layouts

    Challenges of modelling a complex multi-aquifer groundwater system at a national scale: case study from the UK

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    Modelling of the UK groundwater system, composed of multiple discrete aquifers, is undertaken to help assess water resources at the national scale. This groundwater system is made of the major aquifers that overlie each other in some places but which are nonetheless not in a hydraulic contact, and the minor aquifers formed in the superficial deposits. While the major aquifers are not in the direct contact, they are linked by the river network and may exchange water thanks to the aquifer-river interaction processes. In this paper we present a numerical model of this complex system, which is not as demanding to build and run as a fully distributed multi-layered model. The model represents the three most important UK aquifers: Chalk, Jurassic Limestone, and Permo-Triassic Sandstone as separate layers discretized using square buckets that are connected horizontally. These layers are connected to the river network and receive recharge through the buckets that represent their outcrops. An extra layer is also added to represent the minor and non-aquifers. The model was tested at 37 gauging stations distributed across the country. Good fit to the observations was obtained in the steady state run. Further work will include incorporation of abstractions and additional model refinement to represent spatial heterogeneity

    Practising the Space Between: Embodying Belief as an Evangelical Anglican Student

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    This article explores the formation of British evangelical university students as believers. Drawing on ethnographic fieldwork conducted with a conservative evangelical Anglican congregation in London, I describe how students in this church come to embody a highly cognitive, word-based mode of belief through particular material practices. As they learn to identify themselves as believers, practices of reflexivity and accountability enable them to develop a sense of narrative coherence in their lives that allows them to negotiate tensions that arise from their participation in church and broader social structures. I demonstrate that propositional belief – in contexts where it becomes an identity marker – is bound up with relational practices of belief, such that distinctions between “belief in” and “belief that” are necessarily blurred in the lives of young evangelicals

    Morphological differences between habitats are associated with physiological and behavioural trade-offs in stickleback (Gasterosteus aculeatus)

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    F.S. and A.J.W.W. were supported by the Australian Research Council, M.M.W. was supported by The University of St Andrews and R.S.J. and J.T. were supported by Coventry UniversityLocal specialization can be advantageous for individuals and may increase the resilience of the species to environmental change. However, there may be trade-offs between morphological responses and physiological performance and behaviour. Our aim was to test whether habitat-specific morphology of stickleback (Gasterosteus aculeatus) interacts with physiological performance and behaviour at different salinities. We rejected the hypothesis that deeper body shape of fish from habitats with high predation pressure led to decreases in locomotor performance. However, there was a trade-off between deeper body shape and muscle quality. Muscle of deeper-bodied fish produced less force than that of shallow-bodied saltmarsh fish. Nonetheless, saltmarsh fish had lower swimming performance, presumably because of lower muscle mass overall coupled with smaller caudal peduncles and larger heads. Saltmarsh fish performed better in saline water (20 ppt) relative to freshwater and relative to fish from freshwater habitats. However, exposure to salinity affected shoaling behaviour of fish from all habitats and shoals moved faster and closer together compared with freshwater. We show that habitat modification can alter phenotypes of native species, but local morphological specialization is associated with trade-offs that may reduce its benefits.Publisher PDFPeer reviewe

    Use of capnometry to determine the aetiology of persistent pneumothorax following thoracic drain placement in two dogs:Diagnosing pneumothorax using capnometry

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    Thoracic drains are commonly placed in both human and veterinary medicine to treat conditions such as pleural effusion or pneumothorax (Valtolina & Adamantos 2009), and to facilitate chest drainage post-operatively (Tattersall & Welsh 2006; Moores et al. 2007). When there is a failure to achieve intrathoracic negative pressure with a persistent pneumothorax it can be difficult to diagnose the source of the air. The air could originate from damaged lung parenchyma or result from incomplete surgical closure leading to the entrainment of air
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