EU Water Framework Directive : groundwater-dependent rivers and lakes in Northern Ireland

The EU Water Framework Directive (WFD) requires that those rivers and lakes that are dependent on groundwater be identified and the pressures on these analysed such that the risk of not meeting their environmental objectives by 2015, as set out in Article 4, can be assessed. This report describes the methodology for identifying and carrying out risk assessments for groundwater-dependent rivers and lakes in Northern Ireland, as part of the initial characterisation process. The methodology reflects UK Technical Advisory Group (UKTAG) guidance. The report details those river water bodies and lakes that are groundwater dependent and assesses which of these are at risk of being significantly damaged as a result of groundwater abstractions and potentially polluting point sources; diffuse pollution is addressed elsewhere. The report does not address quantitative impacts on rivers and lakes from groundwater abstractions outside specified assessment zones; the study addressed localised impacts rather than those due to cumulative groundwater abstractions which affect the overall groundwater body water balance, and the ‘available groundwater resource’. This is reported elsewhere. The risk assessment for lakes has been restricted to those with an area greater than 50 hectares, these being the reporting units agreed for the UK for initial characterisation. Lough Neagh and Upper and Lower Lough Erne, whilst obviously falling within this category due to their significant scale, are reported elsewhere. Of the 673 river water bodies considered, 564 are classified as groundwater dependent. Of the 17 lakes assessed, 10 are classified as groundwater dependent. None of the groundwater-dependent lakes are assessed as being affected by groundwater abstractions. Flows in four river water bodies are possibly at local risk due to groundwater abstractions, and one, the Breckagh Burn, is probably at risk. All groundwater-dependent lakes have been classified as risk category 2b in relation to potentially polluting point sources. Using an approach that assesses the equivalent categories for river water bodies based on the sum of the number of sources within the surrounding assessment zones, regardless of type, 113 river water bodies were classified as risk category 2a and the remainder risk category 2b. The report details data limitations and gaps in knowledge affecting the initial characterisation process used

Effect of Order-Parameter Suppression on Scattering by Isolated Impurities in Asymmetric Bands

The single-impurity problem in d-wave superconductors with asymmetric bands is discussed. The effect of local order parameter suppression near the impurity is to shift the quasiparticle resonance. Contrary to previous work [A. Shnirman et al., Phys. Rev. B 60, 7517 (1999)] we find that the direction of the shift is not universally towards the strong scattering limit.Comment: 2 pages, 1 figure, proceedings for M2S-HTSC-V

Recent advances in the understanding of mid-ocean ridge tectonics and volcanism using swath-mapping tools

New swath mapping sonar systems have revealed the structure of the mid-ocean ridge (MOR) and sunounding deep ocean floor with unprecedent clarity. These images show that the MOR is partitioned into segments by a variety of offsets such as transform faults, overlapping spreading centers and very fine scale discontinuities which are barely detectable. The smallest scale segments are the fundamental building blocks for creation of new oceanic crust. They are only 2-20 km long and are active, distinct units for only =100-10,000 years. At fast spreading centers, the axial neovolcanic zone is a persistent 300-400 m high elevation produced by the bouyancy of hot rock and magma; it is not a volcanic construction (most of the time and in most plac e ~ )so there is almost no vestige of it off-axis. Along ~60%of its length, the spreading center is characterized by an axial summit caldera produced by volcanic inflation and collapse. The size and shape of the axial high are very sensitive indicators of a relatively steady and robust magma supply at fast-spreading ndges, and have been used successfuliy to predict the location of magma chambers and to forecast recent volcanic emptions including one witnessed from ALVIN in March-Apnl 1991. At intermediate spreading rates, the axial region cools sufficiently for a volcanic constructional edifice to develop episodically and for normal faulting to occur along an axial graben. Under these conditions axial volcanoes are split in two by the axial graben and rernnants can be found on the flanks of spreading centers. At slow-spreading ridges, the magma budget is relatively starved as indicated by a persistent axial nft valley and a highly discontinuous neovolcanic zone, and strong asymmetry in profiles along and across the strike of the ridge

EU Water Framework Directive : groundwater-dependent terrestrial ecosystems in Northern Ireland

The EU Water Framework Directive (WFD) requires those terrestrial ecosystems dependent on groundwater be identified and the anthropogenic pressures acting on the ecosystems analysed. Where significant damage is occurring or could occur due to groundwater factors, then the associated groundwater body is considered to be at risk of not attaining ‘good status’ as defined in the Directive. This report describes the methodology for identifying and carrying out risk assessments for groundwater-dependent terrestrial ecosystems (GWDTEs) in Northern Ireland as part of the initial characterisation process of the WFD. The methodology is based on UK Technical Advisory Group (UKTAG) guidance. 22 designated sites, all Special Areas of Conservation (SACs), have been identified in Northern Ireland as GWDTEs. The report details the level of risk to these GWDTEs from groundwater abstractions and potentially polluting point sources. With one exception, the occurrence of both types of groundwater pressure within the assessment zones of the GWDTEs set by the UKTAG guidance is negligible and hence Risk Category 2b has been determined for initial characterisation. Murlough SAC has been given a Risk Category of 2a for potentially polluting point sources, i.e. it is not at significant risk but confidence that the available information is comprehensive and reliable is low. This is because there are a number of controlled point sources on or close to the GWDTE, on geology that is likely to be in hydraulic connection with it, and some of these sources are concentrated in a small area. It is suggested that improved monitoring of this site would be advisable to increase confidence in the risk assessment. The report highlights a number of aspects that could improve the methodology for identification and assessment of risk for GWDTEs

Symmetrized models of last passage percolation and non-intersecting lattice paths

It has been shown that the last passage time in certain symmetrized models of directed percolation can be written in terms of averages over random matrices from the classical groups $U(l)$, $Sp(2l)$ and $O(l)$. We present a theory of such results based on non-intersecting lattice paths, and integration techniques familiar from the theory of random matrices. Detailed derivations of probabilities relating to two further symmetrizations are also given.Comment: 21 pages, 5 figure

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

Altered engagement of autobiographical memory networks in adult offspring of postnatally depressed mothers

Maternal depression is associated with increased risk for offspring mood and anxiety disorders. One possible impact of maternal depression during offspring development is on the emotional autobiographical memory system. We investigated the neural mechanisms of emotional autobiographical memory in adult offspring of mothers with postnatal depression (N = 16) compared to controls (N = 21). During fMRI, recordings of participants describing one pleasant and one unpleasant situation with their mother and with a companion, were used as prompts to re-live the situations. Compared to controls we predicted the PND offspring would show: greater activation in medial and posterior brain regions implicated in autobiographical memory and rumination; and decreased activation in lateral prefrontal cortex and decreased connectivity between lateral prefrontal and posterior regions, reflecting reduced control of autobiographical recall. For negative situations, we found no group differences. For positive situations with their mothers, PND offspring showed higher activation than controls in left lateral prefrontal cortex, right frontal pole, cingulate cortex and precuneus, and lower connectivity of right middle frontal gyrus, left middle temporal gyrus, thalamus and lingual gyrus with the posterior cingulate. Our results are consistent with adult offspring of PND mothers having less efficient prefrontal regulation of personally relevant pleasant autobiographical memories

The Calogero-Sutherland Model and Polynomials with Prescribed Symmetry

The Schr\"odinger operators with exchange terms for certain Calogero-Sutherland quantum many body systems have eigenfunctions which factor into the symmetric ground state and a multivariable polynomial. The polynomial can be chosen to have a prescribed symmetry (i.e. be symmetric or antisymmetric) with respect to the interchange of some specified variables. For four particular Calogero-Sutherland systems we construct an eigenoperator for these polynomials which separates the eigenvalues and establishes orthogonality. In two of the cases this involves identifying new operators which commute with the corresponding Schr\"odinger operators. In each case we express a particular class of the polynomials with prescribed symmetry in a factored form involving the corresponding symmetric polynomials.Comment: LaTeX 2.09, 31 page

Expanded Vandermonde powers and sum rules for the two-dimensional one-component plasma

The two-dimensional one-component plasma (2dOCP) is a system of $N$ mobile particles of the same charge $q$ on a surface with a neutralising background. The Boltzmann factor of the 2dOCP at temperature $T$ can be expressed as a Vandermonde determinant to the power $\Gamma=q^{2}/(k_B T)$. Recent advances in the theory of symmetric and anti-symmetric Jack polymonials provide an efficient way to expand this power of the Vandermonde in their monomial basis, allowing the computation of several thermodynamic and structural properties of the 2dOCP for $N$ values up to 14 and $\Gamma$ equal to 4, 6 and 8. In this work, we explore two applications of this formalism to study the moments of the pair correlation function of the 2dOCP on a sphere, and the distribution of radial linear statistics of the 2dOCP in the plane

Absence of Persistent Magnetic Oscillations in Type-II Superconductors

We report on a numerical study intended to examine the possibility that magnetic oscillations persist in type II superconductors beyond the point where the pairing self-energy exceeds the normal state Landau level separation. Our work is based on the self-consistent numerical solution for model superconductors of the Bogoliubov-deGennes equations for the vortex lattice state. In the regime where the pairing self-energy is smaller than the cyclotron energy, magnetic oscillations resulting from Landau level quantization are suppressed by the broadening of quasiparticle Landau levels due to the non-uniform order parameter of the vortex lattice state, and by splittings of the quasiparticle bands. Plausible arguments that the latter effect can lead to a sign change of the fundamental harmonic of the magnetic oscillations when the pairing self-energy is comparable to the cyclotron energy are shown to be flawed. Our calculations indicate that magnetic oscillations are strongly suppressed once the pairing self-energy exceeds the Landau level separation.Comment: 7 pages, revtex, 7 postscript figure