1,339 research outputs found

    Galois theory and Lubin-Tate cochains on classifying spaces

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    We consider brave new cochain extensions F(BG +,R) → F(EG +,R), where R is either a Lubin-Tate spectrum E n or the related 2-periodic Morava K-theory K n , and G is a finite group. When R is an Eilenberg-Mac Lane spectrum, in some good cases such an extension is a G-Galois extension in the sense of John Rognes, but not always faithful. We prove that for E n and K n these extensions are always faithful in the K n local category. However, for a cyclic p-group C p r, the cochain extension F(BC p r +,E n ) → F(EC p r +, E n ) is not a Galois extension because it ramifies. As a consequence, it follows that the E n -theory Eilenberg-Moore spectral sequence for G and BG does not always converge to its expected target

    Tracing groundwater flow and sources of organic carbon in sandstone aquifers using fluorescence properties of dissolved organic matter (DOM)

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    The fluorescence properties of groundwaters from sites in two UK aquifers, the Penrith Sandstone of Cumbria and the Sherwood Sandstone of South Yorkshire, were investigated using excitation-emission matrix (EEM) fluorescence spectroscopy. Both aquifers are regionally important sources of public supply water and are locally impacted by anthropogenic pollution. The Penrith Sandstone site is in a rural setting while the Sherwood Sandstone site is in suburban Doncaster. Fluorescence analysis of samples from discrete sample depths in the Penrith Sandstone shows decreasing fulvic-like intensities with depth and also shows a good correlation with CFC-12, an anthropogenic groundwater tracer. Tryptophan- like fluorescence centres in the depth profile may also provide evidence of rapid routing of relatively recent applications of organic slurry along fractures. Fluorescence analysis of groundwater sampled from multi-level piezometers installed within the Sherwood Sandstone aquifer also shows regions of tryptophan-like and relatively higher fulvic-like signatures. The fluorescence intensity profile in the piezometers shows tryptophan-like peaks at depths in excess of 50 metres and mirrors the pattern exhibited by microbial species and CFCs highlighting the deep and rapid penetration of modern recharge due to rapid fracture flow. Fluorescence analysis has allowed the rapid assessment of different types and relative abundances of dissolved organic matter (DOM), and the fingerprinting of different sources of organic carbon within the groundwater system. The tryptophan:fulvic ratios found in the Penrith Sandstone were found to be between (0.5–3.0) and are characteristic of ratios from sheep waste sources. The Sherwood Sandstone has the lowest ratios (0.2–0.4) indicating a different source of DOM, most likely a mixture of terrestrial and microbial sources, although there is little evidence of pollution from leaking urban sewage systems. Results from these two studies suggest that intrinsic fluorescence may be used as a proxy for, or complimentary tool to, other groundwater investigation methods in helping provide a conceptual model of groundwater flow and identifying different sources of DOM within the groundwater system

    Star-graph expansions for bond-diluted Potts models

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    We derive high-temperature series expansions for the free energy and the susceptibility of random-bond qq-state Potts models on hypercubic lattices using a star-graph expansion technique. This method enables the exact calculation of quenched disorder averages for arbitrary uncorrelated coupling distributions. Moreover, we can keep the disorder strength pp as well as the dimension dd as symbolic parameters. By applying several series analysis techniques to the new series expansions, one can scan large regions of the (p,d)(p,d) parameter space for any value of qq. For the bond-diluted 4-state Potts model in three dimensions, which exhibits a rather strong first-order phase transition in the undiluted case, we present results for the transition temperature and the effective critical exponent γ\gamma as a function of pp as obtained from the analysis of susceptibility series up to order 18. A comparison with recent Monte Carlo data (Chatelain {\em et al.}, Phys. Rev. E64, 036120(2001)) shows signals for the softening to a second-order transition at finite disorder strength.Comment: 8 pages, 6 figure

    Introducing the student designer to the role of emotion in design

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    Products satisfy needs beyond the functional. These needs may include aspirations, emotions, cultural and social needs. It is crucial that designers are equipped to deal with the emotional domain of products and users. Carlson (1997) considered emotion to be short term waves of feeling arising without conscious effort, whereas mood, is defined as a longer termed state with less intensity. The authors’ working definition of the ‘emotional domain’ is the range of states of mind (which may influence the body) and which are influenced by internal and external stimuli. These effects tend to be transient although an individual will have a tendency towards a particular state, such as melancholy, happiness, calmness and so on. But even here various stimuli can cause a significant swing in state of mind. But this is a highly individual effect for example, one person may find the new iMac computer delightful and cheerful, where as others, may find it irritating and repulsive

    Nonperturbative Renormalization and the QCD Vacuum

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    We present a self consistent approach to Coulomb gauge Hamiltonian QCD which allows one to relate single gluon spectral properties to the long range behavior of the confining interaction. Nonperturbative renormalization is discussed. The numerical results are in good agreement with phenomenological and lattice forms of the static potential.Comment: 23 pages in RevTex, 4 postscript figure

    Introducing the student designer to the role of emotion in design

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    This is a conference paper.Products satisfy needs beyond the functional. These needs may include aspirations, emotions, cultural and social needs. It is crucial that designers are equipped to deal with the emotional domain of products and users. Carlson (1997) considered emotion to be short term waves of feeling arising without conscious effort, whereas mood, is defined as a longer termed state with less intensity. The authors’ working definition of the ‘emotional domain’ is the range of states of mind (which may influence the body) and which are influenced by internal and external stimuli. These effects tend to be transient although an individual will have a tendency towards a particular state, such as melancholy, happiness, calmness and so on. But even here various stimuli can cause a significant swing in state of mind. But this is a highly individual effect for example, one person may find the new iMac computer delightful and cheerful, where as others, may find it irritating and repulsive

    Selenium poisoning in livestock: a review and progress

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    Selenium in certain soils may be taken up by plants in amounts to render them toxic. Seleniferous forage can be found in most of the western states. Intoxication of livestock by seleniferous plants has been classified as acute and chronic. Acute poisoning results from consumption of plants having high levels of Se; chronic Se poisoning has been described in two forms— alkali disease and blind staggers. Alkali disease is said to result from the consumption of seleniferous grains and grasses, and is manifest by loss of hair, lameness, and loss of weight. Blind staggers is slid to result from the consumption of Se indicator plants and is manifest by wandering, circling, loss of ability to swallow, and blindness. Some research casts doubt on the above classification of Se poisoning. Research using pigs (Sus scrofa domesticus) indicates that the source of Se does not alter the type of lesion or signs of poisoning observed. There are data available that suggest that blind staggers is not related to Se poisoning

    Instream and riparian implications of weed cutting in a chalk river

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    Macrophyte growth is extensive in the iconic chalk streams that are concentrated in southern and eastern England. Widespread and frequent weed cutting is undertaken to maintain their key functions (e.g. flood water conveyance and maintenance of viable fisheries). In this study, a multidisciplinary approach was adopted to quantify coincident physico-chemical responses (instream and riparian) that result from weed cutting and to discuss their potential implications. Three weed cuts were monitored at a site on the River Lambourn (The CEH River Lambourn Observatory) and major instream and riparian impacts were observed. Measurements clearly demonstrated how weed cutting enhanced flood flow conveyance, reduced water levels (river and wetland), increased river velocities, and mobilised suspended sediment (with associated chemicals) and reduced the capacity for its retention within the river channel. Potential implications in relation to flood risk, water resources, downstream water quality, instream and riparian ecology, amenity value of the river, and wetland greenhouse gas emissions were considered. Provided the major influence of macrophytes on instream and riparian environments is fully understood then the manipulation of macrophytes represents an effective management tool that demonstrates the great potential of working with nature

    Classical Open String Models in 4-Dim Minkowski Spacetime

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    Classical bosonic open string models in fourdimensional Minkowski spacetime are discussed. A special attention is paid to the choice of edge conditions, which can follow consistently from the action principle. We consider lagrangians that can depend on second order derivatives of worldsheet coordinates. A revised interpretation of the variational problem for such theories is given. We derive a general form of a boundary term that can be added to the open string action to control edge conditions and modify conservation laws. An extended boundary problem for minimal surfaces is examined. Following the treatment of this model in the geometric approach, we obtain that classical open string states correspond to solutions of a complex Liouville equation. In contrast to the Nambu-Goto case, the Liouville potential is finite and constant at worldsheet boundaries. The phase part of the potential defines topological sectors of solutions.Comment: 25 pages, LaTeX, preprint TPJU-28-93 (the previous version was truncated by ftp...

    Slavnov-Taylor identities in Coulomb gauge Yang-Mills theory

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    The Slavnov-Taylor identities of Coulomb gauge Yang-Mills theory are derived from the (standard, second order) functional formalism. It is shown how these identities form closed sets from which one can in principle fully determine the Green's functions involving the temporal component of the gauge field without approximation, given appropriate input.Comment: 20 pages, no figure
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