Assessment of the environmental impacts of ASR schemes.

This report describes the results of modelling studies undertaken to assess the impacts of ASR on the local environment. Understanding and quantifying these impacts, in relation to other existing or proposed schemes, will be vital in the development, and subsequent licensing of any ASR scheme. As each individual scheme has its own hydrogeological and environmental setting, as well as operational requirements, an all-encompassing model cannot be prescribed. Rather, a set of models, of increasing complexity, have been run for ‘typical’ scenarios to illustrate their use and limitations. They are designed to act as screening tools to assist practitioners, at all stages of an investigation, to decide on the suitability of a site and to identify what additional data are required in order to proceed to the next stage. The models are appended to the report so practitioners can apply them to their specific site, as appropriate

Nitrogen sources, transport and processing in peri-urban floodplains

Peri-urban floodplains are an important interface between developed land and the aquatic environment and may act as a source or sink for contaminants moving from urban areas towards surface water courses. With increasing pressure from urban development the functioning of floodplains is coming under greater scrutiny. A number of peri-urban sites have been found to be populated with legacy landfills which could potentially cause pollution of adjacent river bodies. Here, a peri-urban floodplain adjoining the city of Oxford, UK, with the River Thames has been investigated over a period of three years through repeated sampling of groundwaters from existing and specially constructed piezometers. A nearby landfill has been found to have imprinted a strong signal on the groundwater with particularly high concentrations of ammonium and generally low concentrations of nitrate and dissolved oxygen. An intensive study of nitrogen dynamics through the use of N-species chemistry, nitrogen isotopes and dissolved nitrous oxide reveals that there is little or no denitrification in the majority of the main landfill plume, and neither is the ammonium significantly retarded by sorption to the aquifer sediments. A simple model has determined the flux of total nitrogen and ammonium from the landfill, through the floodplain and into the river. Over an 8 km reach of the river, which has a number of other legacy landfills, it is estimated that 27.5 tonnes of ammonium may be delivered to the river annually. Although this is a relatively small contribution to the total river nitrogen, it may represent up to 15% of the ammonium loading at the study site and over the length of the reach could increase in-stream concentrations by nearly 40%. Catchment management plans that encompass floodplains in the peri-urban environment need to take into account the likely risk to groundwater and surface water quality that these environments pose

Scotland's groundwater monitoring network : its effectiveness for monitoring nitrate

Scotland has had a national groundwater quality monitoring network since the year 2000. One of the main functions of this network is to monitor nitrate concentrations. Nitrate can be elevated in the environment due to modern agricultural practice. Initially there were 150 monitoring sites, but these have been added to, and in 2005, the number of groundwater monitoring points for nitrate was 219, comprising 139 boreholes, 51 springs and 27 wells; 67% of these sites are in agricultural areas. In order to have confidence in the interpretation of data gathered from the network it is important to know the context of the sample points, and in particular whether any sites are compromised by surface contamination or nearby point sources. Prior to this study, many of the sites had not undergone a formal risk assessment and their condition was unclear. In order to improve confidence in the network, and to help act as a baseline before improving the network, the British Geological Survey and the Macaulay Institute were commissioned by the Scottish Executive to carry out a review during the period February-July 2005. The core of the project was to undertake field assessments for 151 sites where no formal assessment had been made previously. Using criteria developed in this project, a judgement was made as to whether the monitoring point was adequate, required improvement or further assessment, or should be considered for removal. For all 219 sites on the network, a zone of influence was estimated using a semi-quantitative method. These zones were used to help focus the field surveys and also to characterise each site using national datasets; for example the monitoring site would be assigned the land use that occupied more than 60% of the zone. These data were then used to conduct an analysis of the factors controlling nitrate concentrations across the network and to help evaluate how effective the network is at monitoring nitrate in Scottish groundwater. Below is a summary of the main results from the project: 1. The fieldwork and analysis of the 151 previously unassessed sites indicated that: • 61 of the 151 sites are adequate and can continue to be monitored with no improvements. • There are serious concerns about 29 of the 151 sites (19% of the sites assessed and 13% of the total nitrate network). These sites should be considered for removal from the network. The sources found to be least reliable were shallow large diameter wells. However, there is little evidence to suggest that the data from these sources collected from 2000 – 2005 has been seriously compromised by point source pollution. • 30 sites require further assessment before being judged suitable. Most of these sites are springs and require additional work to identify the precise source. • 31 sites require improvements to the monitoring points – the improvements range from better sampling protocols to improving the headworks through simple engineering. 2. There is a clear difference between nitrate concentrations measured in the areas designated as nitrate vulnerable zones (NVZs) and other areas. Within the NVZs, the mean concentration is 25 mg-NO3 l-1 and the median 17 mg-NO3 l-1; outside the NVZs, the mean concentration is 9 mg-NO3 l-1 and the median 4.4 mg-NO3 l-1. The data from the network indicate that land use has a large influence on the nitrate concentrations measured in the monitoring network: arable areas, mixed cultivation of both arable and grassland, and areas where dairy, pigs and poultry are reared contribute to the highest nitrate concentrations, with 18% of sites in these areas exceeding 50 mg-NO3 l-1. The most significant control on nitrate concentrations in the monitoring network is the presence of dairy, pigs or poultry within the zone of influence. 4. A considerable number of monitoring sites have lower nitrate concentrations than would be expected from the nitrate pressure. This can be attributed to dilution from rainfall, mixing with older low nitrate waters, denitrification, or the presence of low permeability soil and superficial deposits which slow the movement of high nitrate water into the aquifers. 5. A “gaps” analysis which compared the current network with an idealised network based on nitrate pressures across Scotland indicated that overall the distribution of the current network is generally good. However, there are significant gaps in the improved grassland areas of the Midland Valley and Ayrshire and in the arable areas of Aberdeenshire, while Mid and East Lothian and the Borders are currently overrepresented. The following recommendations are made for the nitrate groundwater quality network in Scotland: 1. Consideration should be given to removing or replacing 29 of the 219 sites, and undertaking further assessments on 30 sites. A further 31 sites would benefit from improvements to the headworks or sampling arrangements. 2. Further statistical analysis should be undertaken to help understand the factors that control the nitrate concentrations in groundwater – particularly the environmental factors that help to reduce the measured nitrate. 3. The network should continue to be concentrated on nitrate pressured areas in Scotland, with approximately 75% of the network in high nitrate areas, and 25% used to monitor background nitrate concentrations in less pressured areas. 4. Any future sites added to the network must undergo a risk assessment similar to the one developed for this study to ensure that the network remains of good quality. 5. The network must continue to reflect the diverse hydrogeological, soil and land use conditions in Scotland. Therefore, both bedrock and superficial aquifers should be monitored in a variety of soil conditions. The network should continue to include different types of sources, although less emphasis should be given to wells, which are generally poor monitoring points. 6. In the future, the data from the network will require to be actively interpreted: an inevitable outcome from having a diverse network is that the results of the monitoring must be interpreted not only in terms of agricultural practice, but in light of the other factors such as geological and environmental conditions. In practice this could mean a regular detailed review (maybe every 2-3 years) of the data from the network. 7. The network will also need to be actively managed to account for various changes in monitoring sites, for example the land use, the condition of the headworks and the pumping rate. This will involve SEPA hydrogeologists having an overview of the network; individual sources being periodically reviewed using a simple checklist; and additional new sources being sought, possibly through the ongoing BGS/SEPA study of baseline groundwater chemistry across Scotland. 8. Wellhead measurements should be taken periodically to help identify denitrification or mixing with older waters. The limited samples taken during this study proved invaluable for interpreting apparently anomalous nitrate concentrations. To undertake this successfully, dedicated sample taps may have to be introduced. 9. A separate programme of focussed monitoring should be developed in tandem with the national groundwater monitoring network to give information on the effects of the action programmes within the NVZs. These sites should be in a controlled environment that will respond rapidly to changes in agricultural practice. The results from these studies can then be upscaled to help interpret changes in the national network as well as be used on their own to help understand the success of the Action Programmes

Hybrid meson decay from the lattice

We discuss the allowed decays of a hybrid meson in the heavy quark limit. We deduce that an important decay will be into a heavy quark non-hybrid state and a light quark meson, in other words, the de-excitation of an excited gluonic string by emission of a light quark-antiquark pair. We discuss the study of hadronic decays from the lattice in the heavy quark limit and apply this approach to explore the transitions from a spin-exotic hybrid to $\chi_b \eta$ and $\chi_b S$ where $S$ is a scalar meson. We obtain a signal for the transition emitting a scalar meson and we discuss the phenomenological implications.Comment: 18 pages, LATEX, 3 ps figure

Lost in translation? Standardising the terminology used in marine invasion biology and updating South African alien species lists

Confusion between terms and ambiguities among definitions have long plagued the field of invasion biology. One result is disruption in flow of information from researchers to policy-makers and managers who rely on science to inform regulatory frameworks and management actions. We reviewed the South African marine biology literature to quantify the current usage of terminology describing marine invasions and found a variety of terms in use, few of which are defined when used. In response, we propose standard terminology that aligns with international practice. We then interpreted the Blackburn unified framework for biological invasions within the marine context and used this as a transparent way to apply the standardised terms to an updated list of marine alien species for the country. This resulted in the recognition of 36 alien and 53 invasive species within South Africa. Most notably, follow-up research is required to confirm the status of at least 11 listed species, the majority of which have been recorded only once, or not in the past 25 years. It is hoped that by standardising terminology, marine science in South Africa will better support authorities charged with managing the threat posed by marine alien species

Visualising the urban green volume: Exploring LiDAR voxels with tangible technologies and virtual models

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.The distribution of vegetation within urban zones is well understood to be important for delivery of a range of ecosystem services. While urban planners and human geographers are conversant with methodologies for describing and exploring the volumetric nature of built spaces there is less research that has developed imaginative ways of visualising the complex spatial and volumetric structure of urban vegetation from the treetops to the ground. Using waveform LiDAR data to measure the three-dimensional nature of the urban greenspace, we explore different ways of virtually, and tangibly engaging with volumetric models describing the 3D distribution of urban vegetation. Using waveform LiDAR data processed into voxels (volumetric pixels) and experimenting with a variety of creative approaches to visualise the volumetric nature of the data, we describe the development of new methods for mapping the urban green volume, using a combination of Geographic Information Systems (GIS), Minecraft, 3D printing and Computer Numerical Control (CNC) milling processes. We demonstrate how such methodologies can be used to reveal and explore the complex nature of the urban green volume. We also describe the outcome of using these models to engage diverse audiences with the volumetric data. We explain how the products could be used readily by a range of urban researchers and stakeholders: from town and city councils, to architects and ecologists

Applications of Hilbert Module Approach to Multivariable Operator Theory

A commuting $n$-tuple $(T_1, \ldots, T_n)$ of bounded linear operators on a Hilbert space \clh associate a Hilbert module $\mathcal{H}$ over $\mathbb{C}[z_1, \ldots, z_n]$ in the following sense: $$\mathbb{C}[z_1, \ldots, z_n] \times \mathcal{H} \rightarrow \mathcal{H}, \quad \quad (p, h) \mapsto p(T_1, \ldots, T_n)h,$$where $p \in \mathbb{C}[z_1, \ldots, z_n]$ and $h \in \mathcal{H}$. A companion survey provides an introduction to the theory of Hilbert modules and some (Hilbert) module point of view to multivariable operator theory. The purpose of this survey is to emphasize algebraic and geometric aspects of Hilbert module approach to operator theory and to survey several applications of the theory of Hilbert modules in multivariable operator theory. The topics which are studied include: generalized canonical models and Cowen-Douglas class, dilations and factorization of reproducing kernel Hilbert spaces, a class of simple submodules and quotient modules of the Hardy modules over polydisc, commutant lifting theorem, similarity and free Hilbert modules, left invertible multipliers, inner resolutions, essentially normal Hilbert modules, localizations of free resolutions and rigidity phenomenon. This article is a companion paper to "An Introduction to Hilbert Module Approach to Multivariable Operator Theory".Comment: 46 pages. This is a companion paper to arXiv:1308.6103. To appear in Handbook of Operator Theory, Springe

Wave Function Based Characteristics of Hybrid Mesons

We propose some extensions of the quark potential model to hybrids, fit them to the lattice data and use them for the purpose of calculating the masses, root mean square radii and wave functions at the origin of the conventional and hybrid charmonium mesons. We treat the ground and excited gluonic field between a quark and an antiquark as in the Born-Oppenheimer expansion, and use the shooting method to numerically solve the required Schr$\ddot{\textrm{o}}$dinger equation for the radial wave functions; from these wave functions we calculate the mesonic properties. For masses we also check through a Crank Nichelson discretization. For hybrid charmonium mesons, we consider the exotic quantum number states with $J^{PC} = 0^{+ -}, 1^{- +}$ and $2^{+ -}$. We also compare our results with the experimentally observed masses and theoretically predicted results of the other models. Our results have implications for scalar form factors, energy shifts, magnetic polarizabilities, decay constants, decay widths and differential cross sections of conventional and hybrid mesons.Comment: 13 pages, 6 figures, Erratum is submitted to EPJ