3,408 research outputs found
A Discrete Inverse Scattering Transform for Q3
We derive a fully discrete Inverse Scattering Transform as a method for
solving the initial-value problem for the Q3 lattice
(difference-difference) equation for real-valued solutions. The initial
condition is given on an infinite staircase within an N-dimensional lattice and
must obey a given summability condition. The forward scattering problem is
one-dimensional and the solution to Q3 is expressed through the
solution of a singular integral equation. The solutions obtained depend on N
discrete independent variables and N parameters.Comment: 26 page
Organic farming and agri-environmental stewardship schemes in Devon
A postal survey was undertaken in North Devon looking at entry into England Rural Development Programme (ERDP) environmental schemes in relation to farming system and markets. The main survey was based in and around the North Devon Biosphere reserve. Significantly more farms replied who had Countryside Stewardship (CSS) agreements than from those who were not in the scheme. There was a greater likelihood of small farms joining CSS as were beef, sheep and cereal farms compared with dairy farms. A greater percent of organic farms had CSS agreements compared with the conventional farms. A smaller telephone survey in a CSS target area in South Devon was also undertaken which confirmed these results. Those farms with CSS agreements were more likely to have joined or be joining the new agri-environmental schemes
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The online multi-agency support barometer
This report presents the findings of a small feasibility study which sought to investigate the use of an online risk management Barometer. The barometer was developed with a view to helping multiple agencies communicate about vulnerable and 'at risk' patients within mental health settings.The Barometer is an online tool which allows staff from multiple agencies to access and share information with other staff if a patient is at risk.The key aims and objectives of this small research project were i) to evaluating how professionals felt about their current risk assessment tools, ii) to assess the ease of use and the relevance of questions within the Barometer tool and iii) to discuss some potential modifications/problem areas of incorporating the Barometer tool within mental health services and across a multi-disciplinary perspective.The research was conducted in three mental services within the South Essex Partnership Trust (2 x CAMHS and 2 x Adult Services) using a mixed-methods approach
Seeing the Other Side of the Coin: (Re)Constructing the Normative Flipside to Marx’s Sociology.
This paper argues that, Marx’s insistences notwithstanding, there is an ethical core to Marx’s critique of capitalism. I attempt to establish this claim through presenting salient points of Marx’s critique. From this basis, I move on to discuss Marx’s conception of human nature and the way in which it is typically frustrated under pre-communist societies. This frustration is the basis for a moral preference for communism. After pausing briefly to consider the possible criticism that this moral preference is mere ideology, I conclude with the normative heart of the matter. This is addressed by underscoring principal similarities between Marx’s work and Aristotle’s ethical project, insofar as each comprehends an intuitive description of the good life and an analysis of the prerequisites for obtaining it. A grasp of this similarity opens the door to understanding the normative flip side of Marx’s intellectual project
Experimental and Theoretical Basis for a Closed-Form Spectral BRDF Model
The microfacet class of BRDF models is frequently used to calculate optical scatter from realistic surfaces using geometric optics, but has the disadvantage of not being able to consider wavelength dependence. This dissertation works toward development of a closed-form approximation to the BRDF that is suitable for hyperspectral remote sensing by presenting measured BRDF data of 12 different materials at four different incident angles and up to seven different wavelengths between 3.39 and 10.6 micrometer. The data was intended to be fit to various microfacet BRDF models to determine an appropriate form of the wavelength scaling. However, when fitting the microfacet models to measured data, the results indicated a breakdown in the microfacet model itself. To overcome this deficiency, elements of microfacet BRDF models are compared to elements of scalar wave optics BRDF models, which inherently contain a wavelength dependence. This analysis led to a theoretical understanding of how to modify microfacet BRDF models to maintain the simplicity of a closed-form model, while better approximating the underlying physics
Erewhon' by Samuel Butler
Fictional aeolian devices in the novel Erewhon by Samuel Butle
Inverse Scattering Transform Method for Lattice Equations
The main original contribution of this thesis is the development of a fully discrete inverse scattering transform (IST) method for nonlinear partial difference equations. The equations we solve are nonlinear partial difference equations on a quad-graph, also called lattice equations, which are known to be multidimensionally consistent in N dimensions for arbitrary N. Such equations were discovered by Nijhoff, Quispel and Capel and Adler and later classified by Adler, Bobenko and Suris. The main equation solved by our IST framework is the Q3δ lattice equation. Our approach also solves all of its limiting cases, including H1, known as the lattice potential KdV equation. Our results provide the discrete analogue of the solution of the initial value problem on the real line. We provide a rigorous justification that solves the problem for wide classes of initial data given along initial paths in a multidimensional lattice. Moreover, we show how soliton solutions arise from the IST method and also utilise asymptotics of the eigenfunctions to construct infinitely many conservation laws
Effects of Crude Oil on Aquatic Insects of Tundra Ponds
Aquatic insects are numerous and important in the ecology of tundra thaw ponds, comprising most of the biomass and production. The most common types are the caddisflies Asynarchus and Micrasema, the stonefly Nemoura, the beetle Agabus and especially larvae of the fly family Chironomidae. Studies in vitro showed no detectable mortality of these insects at doses of oil up to 1.5 l/m² Prudhoe Bay crude oil. However, field experiments on two ponds with application rates of about 10 l/m² (Pond E, 1970) and 0.24 l/m² (Pond Omega, 1975) both indicated that selective elimination of Asynarchus and Nemoura had occurred. Chironomidae in Pond Omega displayed much lower rates of adult emergence in 1976 and 1977 than in 1975, immediately before and after oil treatment, with several species in the tribe Tanytarsini most reduced. Pond E did not show low emergence rates, but the proportion of Orthocladiinae was much higher than in reference ponds. Trichotanypus was severely reduced in Pond Omega but unusually abundant in Pond E in 1976 and 1977. Effects of oil seem to be different for different species, and occur at some point during the late larval stages of insects or at metamorphosis, but toxicity experiments did not confirm this. Oil may also interfere with reproduction in insect species which remain mainly on or near the pond surface as adults. Apparent effects in field experiments are not entirely consistent with observations of Canadian researchers. Nevertheless there were several similarities and both followed patterns like those observed in marine benthic communities, such as greater effects on shore fauna, greater effects of low-molecular-weight hydrocarbons, and species-specificity of effects. There is no indication of recovery of Nemoura, Asynarchus or Tanytarsini in Pond E seven years after the spill, but biomass and abundance of the other aquatic insects remains high. We recommend that clean-up measures avoid introducing solvents or dispersants, which might be toxic to insects in the pond
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