Geology and land-use planning: Great Broughton-Lamplugh area, Cumbria. Part 2, land-use planning

This report is one of two which describes the results of a research project funded jointly by the Department of the Environment and the British Geological Survey. The objectives of the project were to provide an up-to-date geological database for the Great Broughton-Lamplugh area as a foundation for land use and development, effective future geological research and the safeguarding of mineral resources. Part 1 (BGS Technical Report WA/92/54), available separately, describes the geology. The results, with particular emphasiso n landuse planning, are described here. The present study is the third DOE sponsored applied geological mapping project in Cumbria; previous surveys have covered the Workington and Maryport, and Dearham and Gilcrux areas

Too good to waste: Creating biochar from cleared vegetation as a soil improver and carbon sink

Road construction has a considerable carbon footprint and is likely to be impacted significantly by international and national responses to climate change. Although avoidance of carbon emissions during the design and construction phases is preferred, it is inevitable that some carbon emissions will result in large projects, due to the carbon intensive nature of road construction. Typical offset projects have focused around the biosequestration of carbon, including large-scale tree planting. Whilst tree planting projects achieve broader benefits from reafforestation, concerns surrounding the biodiversity value of largely monoculture, agro-forestry projects are adding to traditional criticisms such as the measurability and permanency. Concerns over tree planting as an approach to offsetting have paved the way for consideration of other biological methods for carbon sequestration that are better able to respond to tests of measurability and permanency and attempt to preserve the biodiversity value of cleared land. Biochar, charcoalised woody biomass, is a soil improver, which is being investigated globally due to its potential to store carbon in the soil for extremely long time periods. On-site production of biochar using cleared vegetation is an approach to carbon offsetting that allows for both the sequestration of carbon in the soil and enhances revegetation activities in the road reserve. Low technology approaches are practical, using existing road construction equipment to dig pits in which the vegetation is slowly carbonised through low oxygen combustion. High technology but portable approaches for on-site generation using modern biomass to energy conversion technologies (pyrolysis and gasification) are also possible and able to produce biochar and renewable fuels, which can be used in a number of conventional generation technologies such as internal combustion engines and turbines. Roadside vegetation used in modern biomass pyrolysis technologies has the potential to produce around 30 kg of carbon sequestration for each gigajoule of renewable fuel produced. Biochar may sequester up to 50 per cent of the carbon in the original vegetation, having the potential to become an important part of future revegetation activities in road construction This paper will discuss several approaches to onsite biochar production from road vegetation, in particular a recent trial from Western Australia and the opportunities for reducing carbon emissions and the sequestration of carbon that would otherwise be burnt or left to rapidly decay as chipped or mulched material

Automated identification of Fos expression

The concentration of Fos, a protein encoded by the immediate-early gene c-fos, provides a measure of synaptic activity that may not parallel the electrical activity of neurons. Such a measure is important for the difficult problem of identifying dynamic properties of neuronal circuitries activated by a variety of stimuli and behaviours. We employ two-stage statistical pattern recognition to identify cellular nuclei that express Fos in two-dimensional sections of rat forebrain after administration of antipsychotic drugs. In stage one, we distinguish dark-stained candidate nuclei from image background by a thresholding algorithm and record size and shape measurements of these objects. In stage two, we compare performance of linear and quadratic discriminants, nearest-neighbour and artificial neural network classifiers that employ functions of these measurements to label candidate objects as either Fos nuclei, two touching Fos nuclei or irrelevant background material. New images of neighbouring brain tissue serve as test sets to assess generalizability of the best derived classification rule, as determined by lowest cross-validation misclassification rate. Three experts, two internal and one external, compare manual and automated results for accuracy assessment. Analyses of a subset of images on two separate occasions provide quantitative measures of inter- and intra-expert consistency. We conclude that our automated procedure yields results that compare favourably with those of the experts and thus has potential to remove much of the tedium, subjectivity and irreproducibility of current Fos identification methods in digital microscopy

Exploring experiential differences in everyday activities – A focused ethnographic study in the homes of people living with memory-led Alzheimer's disease and posterior cortical atrophy

Background Supporting ageing in place, quality of life and activity engagement are public health priorities for people living with dementia, but little is known about the needs and experiences of community-dwelling people with rarer forms of dementia with lesser known symptoms. Posterior cortical atrophy (PCA) is a rare form of dementia usually caused by Alzheimer's disease but which is characterised by diminished visual processing (rather than a dominant memory problem), which poses challenges for maintaining independence and accessing appropriate support. Methods This study used a comparative qualitative design and focussed ethnographic methods to explore experiential differences in activity engagement for 10 people with the most common, memory-led presentation of Alzheimer's disease and 10 people with posterior cortical atrophy within their everyday home environments. Results While the data collection revealed much rich variation in individual and contextual factors, some tentative high-level differences in the experiences of everyday activities could be drawn out, seemingly attributable to the different diagnoses' differing dominant symptoms. These included people with posterior cortical atrophy being less likely to use environmental cues to initiate activities, and more likely to withhold from asking for support because of preserved insight into the impact of this on carers. This lack of initiation of activities could be misinterpreted as apathy. People with posterior cortical atrophy also were discouraged from engaging in activities by disorientation within the home, and difficulties localising, identifying and manipulating objects. People with the more common, memory-led presentation of Alzheimer's disease exhibited more memory-based difficulties with engaging with activities such as forgetting planned activities, where to locate the items required for an activity and the steps involved. Despite these distinct symptom-led challenges, all participants and their family members demonstrated resourcefulness and resilience in making creative adaptations to support continued engagement in everyday activities, supporting the widely reported management strategies of people with dementia of the Alzheimer's type more generally. Conclusions These findings offer helpful insights into some the differing impacts dementia related visual and memory impairments can have on everyday activity engagement, which will be helpful for others navigating these challenges and the health and social care practitioners working with people affected by these conditions. The findings also highlight the vast individual variation in the multitude of individual and contextual factors involved in everyday activity engagement, and suggest important areas for future work utilising methods which are similarly high in ecological validity and accessibility as the home-based focussed ethnographic methods utilised here

Sound Propagation in Nematic Fermi Liquid

We study the longitudinal sound propagation in the electronic nematic Fermi liquid where the Fermi surface is distorted due to the spontaneously broken rotational symmetry. The behavior of the sound wave in the nematic ordered state is dramatically different from that in the isotropic Fermi liquid. The collective modes associated with the fluctuations of the Fermi surface distortion in the nematic Fermi liquid leads to the strong and anisotropic damping of the sound wave. The relevance of the nematic Fermi liquid in doped Mott insulator is discussed.Comment: 4 pages, no figur

Effective interactions between parallel-spin electrons in two-dimensional jellium approaching the magnetic phase transition

We evaluate the effective interactions in a fluid of electrons moving in a plane, on the approach to the quantum phase transition from the paramagnetic to the fully spin-polarized phase that has been reported from Quantum Monte Carlo runs. We use the approach of Kukkonen and Overhauser to treat exchange and correlations under close constraints imposed by sum rules. We show that, as the paramagnetic fluid approaches the phase transition, the effective interactions at low momenta develop an attractive region between parallel-spin electrons and a corresponding repulsive region for antiparallel-spin electron pairs. A connection with the Hubbard model is made and used to estimate the magnetic energy gap and hence the temperature at which the phase transition may become observable with varying electron density in a semiconductor quantum well.Comment: 11 pages, 3 figure

Signatures of Electronic Nematic Phase at Isotropic-Nematic Phase Transition

The electronic nematic phase occurs when the point-group symmetry of the lattice structure is broken, due to electron-electron interactions. We study a model for the nematic phase on a square lattice with emphasis on the phase transition between isotropic and nematic phases within mean field theory. We find the transition to be first order, with dramatic changes in the Fermi surface topology accompanying the transition. Furthermore, we study the conductivity tensor and Hall constant as probes of the nematic phase and its transition. The relevance of our findings to Hall resistivity experiments in the high-$T_c$ cuprates is discussed.Comment: 5 pages, 3 figure

Space as a low-temperature regime of graphs

I define a statistical model of graphs in which 2-dimensional spaces arise at low temperature. The configurations are given by graphs with a fixed number of edges and the Hamiltonian is a simple, local function of the graphs. Simulations show that there is a transition between a low-temperature regime in which the graphs form triangulations of 2-dimensional surfaces and a high-temperature regime, where the surfaces disappear. I use data for the specific heat and other observables to discuss whether this is a phase transition. The surface states are analyzed with regard to topology and defects.Comment: 22 pages, 12 figures; v3: published version; J.Stat.Phys. 201

Crystallization of a classical two-dimensional electron system: Positional and orientational orders

Crystallization of a classical two-dimensional one-component plasma (electrons interacting with the Coulomb repulsion in a uniform neutralizing positive background) is investigated with a molecular dynamics simulation. The positional and the orientational correlation functions are calculated for the first time. We have found an indication that the solid phase has a quasi-long-range (power-law) positional order along with a long-range orientational order. This indicates that, although the long-range Coulomb interaction is outside the scope of Mermin's theorem, the absence of ordinary crystalline order at finite temperatures applies to the electron system as well. The `hexatic' phase, which is predicted between the liquid and the solid phases by the Kosterlitz-Thouless-Halperin-Nelson-Young theory, is also discussed.Comment: 3 pages, 4 figures; Corrected typos; Double columne

Lattice-switch Monte Carlo

We present a Monte Carlo method for the direct evaluation of the difference between the free energies of two crystal structures. The method is built on a lattice-switch transformation that maps a configuration of one structure onto a candidate configuration of the other by `switching' one set of lattice vectors for the other, while keeping the displacements with respect to the lattice sites constant. The sampling of the displacement configurations is biased, multicanonically, to favor paths leading to `gateway' arrangements for which the Monte Carlo switch to the candidate configuration will be accepted. The configurations of both structures can then be efficiently sampled in a single process, and the difference between their free energies evaluated from their measured probabilities. We explore and exploit the method in the context of extensive studies of systems of hard spheres. We show that the efficiency of the method is controlled by the extent to which the switch conserves correlated microstructure. We also show how, microscopically, the procedure works: the system finds gateway arrangements which fulfill the sampling bias intelligently. We establish, with high precision, the differences between the free energies of the two close packed structures (fcc and hcp) in both the constant density and the constant pressure ensembles.Comment: 34 pages, 9 figures, RevTeX. To appear in Phys. Rev.