Defining Petrophysical Units of the Palmer Deep Sites from Leg 178

Palmer Deep, on the inner continental shelf southwest of Anvers Island off the Antarctic Peninsula, is a glacially overdeepened basin consisting of three subbasins. Two sites, 1098 and 1099, were drilled in the Palmer Deep area. A high-resolution porosity curve has been calculated from density data and subsequently plotted against the shipboard lithologic logs. These new data correspond accurately to the lithologic logs, magnetic susceptibility, and gamma ray attenuation (GRA) density data and offer information on the heterogeneity of the sediments. Petrophysical groups have been generated to investigate interrelationships between different physical attributes. To develop these petrophysical groups, crossplots of the available physical properties data were performed. The results for the GRA density and magnetic susceptibility crossplots demonstrate distinct clusters. Plotting the magnetic susceptibility and GRA density data logs (divided into these new petrophysical groups) against lithology provided information to subdivide the lithologic unit(s) into a series of petrophysical units

Wilderness attribute mapping in the United Kingdom

A wilderness continuum concept can identify the wilder areas of Britain. Geographical Information Systems are used to present information on these areas and solicit public opinion as to which factors are perceived to be important wilderness quality indicators. Consensus maps are compiled from a composite of individual responses and the results compared to Britain’s network of protected areas

SimCrime: A Spatial Microsimulation Model for the Analysing of Crime in Leeds.

This Working Paper is a part of PhD thesis 'Modelling Crime: A Spatial Microsimulation Approach' which aims to investigate the potential of spatial microsimulation for modelling crime. This Working Paper presents SimCrime, a static spatial microsimulation model for crime in Leeds. It is designed to estimate the likelihood of being a victim of crime and crime rates at the small area level in Leeds and to answer what-if questions about the effects of changes in the demographic and socio-economic characteristics of the future population. The model is based on individual microdata. Specifically, SimCrime combines individual microdata from the British Crime Survey (BCS) for which location data is only at the scale of large areas, with census statistics for smaller areas to create synthetic microdata estimates for output areas ?(OAs) in Leeds using a simulated annealing method. The new microdata dataset includes all the attributes from the original datasets. This allows variables such as crime victimisation from the BCS to be directly estimated for OAs

Field Studies of the Population Dynamics of the Spotted Spiny Lobster Panulirus guttatus (Latreille) at Bermuda

Results of a study on the population dynamics of the spotted spiny lobster Panulirus guttatus (Latreille) at Bermuda are described. The annual growth coefficients (K) for male and female spotted spiny lobsters P. guttatus are estimated at 0.22 and 0.16 from size frequency analyses. Annual total mortality, fishing mortality, natural mortality, and recruitment coefficients (Z, F, M, and R) for 1987 were estimated at 0.79, 0.46, 0.33, and 0.79, respectively, based on length and weight data and the exploitation rate (E = 0.58) was estimated from population weight data. The catchability coefficient (q) for 1987 was estimated at 3.9 X 10-6/ trap-haul from the estimate of F and the 1987 data for total effort. The stock size (N1987) of trappable P. guttatus lobsters at the start of calendar year 1987 was estimated at approximately 71 X 103 individuals from q and industry catch and effort data. The population showed marked spatial preference with the density at the reef crest an order of magnitude greater than in the reef system as a whole

A spatio-temporal modelling framework for assessing the impact of weed management technologies on the spread of herbicide resistance

This paper presents a spatio-temporal modelling framework for predicting the spread of herbicide resistance. It includes a model of the population dynamics of weeds growing in competition with crops, a polygenic model of the development of herbicide resistance, and gene transfer by means of pollen and seed movement. The framework is used to predict the long-term spread of resistant weeds given different integrated weed management choices combining tillage and herbicide treatments, and seed capture at harvest. The model’s predictions will be used to devise management options that minimise the spread of herbicide resistant weeds

Fast dispersal simulation using bivariate quantiles

Spatial-temporal models of the spread of invasive species can require dispersal of large numbers of individuals from many locations at recurrent times, making them slow to execute. We present a fast algorithm for simulating dispersal of large numbers of individuals. The algorithm is stochastic and can be applied using any bivariate probability density function as the dispersal kernel. It achieves computational efficiency while still allowing the simulation of rare and important long-distance dispersals by combining different approaches for within and outside the tail of the dispersal kernel. The tail is specified by a given bivariate quantile, where the q-th bivariate quantile is defined to be the contour of equiprobability within which a proportion 0< q <1 of dispersing individuals will settle. We provide a method for finding bivariate quantiles that can be applied to any bivariate dispersal kernel derived from independent densities for distance and direction of dispersal. To illustrate this approach, we show how the Cauchy distribution can be used to produce isotropic and anisotropic bivariate dispersal kernels by assuming that the direction of dispersal is either random or takes a von Mises distribution. We show that the algorithm is considerably faster than generating individual random samples from a bivariate dispersal kernel. It also performs better for larger grid sizes, and when there are larger numbers of individuals to be spread, than an approach that generates samples from a Binomial distribution for each grid cell using the probability of dispersal to that cell. The degree of computational efficiency achieved by the algorithm compared to the Binomial approach depends upon the speed with which random sample scan be generated from the tail of the bivariate dispersal kernel used

Characterisation of Quaternary sediments from East Anglia

This report describes the mineralogical investigations of Quaternary sediments,mainly Cromer Till, collected from East Anglia. The main aim of the work was to characterise the mineralogical and physical properties of the till samples to facilitate correlation between tills from different localities. The clast composition of the samples was determined using a binocular microscope and the mineralogy of the matrix was determined using X-ray diffraction and thermogravimetry. Calibration charts were used to quantify the amount of quartz and calcite present. Cumulative frequency graphs were plotted from the particle-size data to determine the mean, median, standard deviation and skewness. Also ternary sand/silt/clay diagrams were plotted. The Cromer Till samples typically contained 2% gravel (mainly flint, sandstone, quartz and chalk), 45% sand, 31 % silt and 22% clay. The Starston Till contained 12% gravel (mainly flint), 46% sand, 16% silt and 26% clay. The 'Clay' from Sea Palling contained 1 % gravel (mainly flint), 10% sand, 78% silt and 11 % clay. The Lowestoft Till samples had different particle-size distributions and the gravel consisted mainly of chalk.The Crag Clay samples contained 1 % gravel (mainly sandstone), 11 % sand, 49% silt and 39% clay. The Blue Clay samples contained virtually no gravel, 4% sand, 59% silt and 37% silt. The Holocene sample contained 1 % gravel (mainly flint), 21% sand, 39% silt and 39% clay. The CaC03 contents and particle-size distributions of the Cromer Till samples were compared with published data (Lunkka, 1994). Based upon this comparison the samples were tentatively classified as either Walcott Diamicton, Happisburgh Diamicton or Norwich Brickearth. The 'Blue Clay' samples were also tentatively classified as Crag Clay. Recommendations for further work include detailed logging and sampling of coastal sections; collection of large samples for more accurate clast analysis ; and heavy mineral analysis

Conserved charges and supersymmetry in principal chiral and WZW models

Conserved and commuting charges are investigated in both bosonic and supersymmetric classical chiral models, with and without Wess-Zumino terms. In the bosonic theories, there are conserved currents based on symmetric invariant tensors of the underlying algebra, and the construction of infinitely many commuting charges, with spins equal to the exponents of the algebra modulo its Coxeter number, can be carried out irrespective of the coefficient of the Wess-Zumino term. In the supersymmetric models, a different pattern of conserved quantities emerges, based on antisymmetric invariant tensors. The current algebra is much more complicated than in the bosonic case, and it is analysed in some detail. Two families of commuting charges can be constructed, each with finitely many members whose spins are exactly the exponents of the algebra (with no repetition modulo the Coxeter number). The conserved quantities in the bosonic and supersymmetric theories are only indirectly related, except for the special case of the WZW model and its supersymmetric extension.Comment: LaTeX; 49 pages; v2: minor changes and additions to text and ref

Generation of defects and disorder from deeply quenching a liquid to form a solid

We show how deeply quenching a liquid to temperatures where it is linearly unstable and the crystal is the equilibrium phase often produces crystalline structures with defects and disorder. As the solid phase advances into the liquid phase, the modulations in the density distribution created behind the advancing solidification front do not necessarily have a wavelength that is the same as the equilibrium crystal lattice spacing. This is because in a deep enough quench the front propagation is governed by linear processes, but the crystal lattice spacing is determined by nonlinear terms. The wavelength mismatch can result in significant disorder behind the front that may or may not persist in the latter stage dynamics. We support these observations by presenting results from dynamical density functional theory calculations for simple one- and two-component two-dimensional systems of soft core particles.Comment: 25 pages, 11 figure