3,428 research outputs found

    Miocene deep water agglutinated foraminifera from Viosca Knoll, offshore Louisiana (Gulf of Mexico)

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    An exploration well from the Gulf of Mexico, Amoco Viosca Knoll-915, has been studied in order to document the Neogene foraminiferal assemblages. Ditch cuttings samples from the Amoco V.K. 915 well yielded diverse assemblages of agglutinated and calcareous benthic foraminifera over a stratigraphic interval of 2940 m. Three species associations can be identified in the studied interval; the stratigraphical location of these associations is evident when total agglutinated species abundance for each sampling interval is plotted. In this study we use a combination of morphotype habitat preference and test functional morphology to interpret depositional environments. The associations indicate a change from a well-ventilated water column, to the development of a strong oxygen minimum zone characterised by alveolar foraminifera. The species composition of the lowermost association indicates a depositional environment dominated by fine-grained overbank fines and channel levee deposits, in agreement with sedimentological data. Colour plates of key agglutinates species are presented, created using digital image manipulation techniques (Palaeovision Technique, NHM)

    Mapping Inequality in London: A Different Approach

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    Maps provide an effective means of distributing ideas simply, creating a format where spatial data can be easily understood. However, a lot of people are not aware where administrative boundaries lie, limiting their appeal for educating the public on important issues such as poverty and inequality. This paper seeks to utilize a well-known cartographic map design, the London Underground map, to aid data dissemination of the complex issues surrounding inequality and deprivation in London. A discussion of the relevance of this approach to researching inequality in London, as well as how this fits in with previous approaches to mapping poverty is provided. An example using the recent release of the Indices of Multiple Deprivation 2010 shows the usefulness of this design

    A neighbourhood level mortality classification of England and Wales, 2006-2009

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    The paper provides an overview of a neighbourhood level classification of mortality for England and Wales (2006–2009). Standardised mortality ratios for 63 causes of death were calculated for middle super output areas (weighted by prevalence). A k-means partitional method was used to classify the data. An eight cluster solution was found to best segment mortality patterns. Clusters mostly differentiated in terms of prevalence, however the importance of neurodegenerative diseases and causes related to unhealthy behaviours were important. The results describe a neighbourhood classification that can be an important tool to help inform policy development, resource allocation and targeting of services

    Open String Thermodynamics and D-Branes

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    We study the thermodynamics of open superstrings in the presence of pp-dimensional D-branes. We get some finite temperature dualities relating the one-loop canonical free energy of open strings to the self-energy of D-branes at dual temperature. For the open bosonic string the inverse dual temperature is, as expected, the dual length under T-duality, 4π2αâ€Č/ÎČ4\pi^{2}\alpha^{'}/\beta. On the contrary, for the SO(N)SO(N), type-I superstring the dual temperature is given by ÎČ\beta-duality, 2π2αâ€Č/ÎČ2\pi^{2}\alpha^{'}/\beta. We also study the emergence of the Hagedorn singularity in the dual description as triggered by the coupling of the D-brane to unphysical tachyons as well as the high temperature limit.Comment: 16 pages, harvmac (b), epsf, 2 figures included. Minor changes; discussion in section 4 has been expanded and two footnotes and a reference adde

    GESSS Machine Design Committee Reports 1972

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    Theory of small aspect ratio waves in deep water

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    In the limit of small values of the aspect ratio parameter (or wave steepness) which measures the amplitude of a surface wave in units of its wave-length, a model equation is derived from the Euler system in infinite depth (deep water) without potential flow assumption. The resulting equation is shown to sustain periodic waves which on the one side tend to the proper linear limit at small amplitudes, on the other side possess a threshold amplitude where wave crest peaking is achieved. An explicit expression of the crest angle at wave breaking is found in terms of the wave velocity. By numerical simulations, stable soliton-like solutions (experiencing elastic interactions) propagate in a given velocities range on the edge of which they tend to the peakon solution.Comment: LaTex file, 16 pages, 4 figure

    Propagators on the two-dimensional light-cone

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    Light-cone quantization procedure recently presented is applied to the two-dimensional light-cone theories. By introducing the two distinct null planes it is shown that the modification term in the two-dimensional massless light-cone propagators suggested about twenty years ago vanishs.Comment: LATEX, 9page
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