6,412 research outputs found

    Putting Soybeans into Permanent Farming

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    Petrogenetic processes in the ultramafic, alkaline and carbonatitic magmatism in the Kola Alkaline Province: a review

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    Igneous rocks of the Devonian Kola Alkaline Carbonatite Province (KACP) in NW Russia and eastern Finland can be classified into four groups: (a) primitive mantle-derived silica-undersaturated silicate magmas; (b) evolved alkaline and nepheline syenites; (c) cumulate rocks; (d) carbonatites and phoscorites, some of which may also be cumulates. There is no obvious age difference between these various groups, so all of the magma-types were formed at the same time in a relatively restricted area and must therefore be petrogenetically related. Both sodic and potassic varieties of primitive silicate magmas are present. On major element variation diagrams, the cumulate rocks plot as simple mixtures of their constituent minerals (olivine, clinopyroxene, calcite etc). There are complete compositional trends between carbonatites, phoscorites and silicate cumulates, which suggests that many carbonatites and phoscorites are also cumulates. CaO/Al2O3 ratios for ultramafic and mafic silicate rocks in dykes and pipes range up to 5, indicating a very small degree of melting of a carbonated mantle at depth. Damkjernites appear to be transitional to carbonatites. Trace element modelling indicates that all the mafic silicate magmas are related to small degrees of melting of a metasomatised garnet peridotite source. Similarities of the REE patterns and initial Sr and Nd isotope compositions for ultramafic alkaline silicate rocks and carbonatites indicate that there is a strong relationship between the two magma-types. There is also a strong petrogenetic link between carbonatites, kimberlites and alkaline ultramafic lamprophyres. Fractional crystallisation of olivine, diopside, melilite and nepheline gave rise to the evolved nepheline syenites, and formed the ultramafic cumulates. All magmas in the KACP appear to have originated in a single event, possibly triggered by the arrival of hot material (mantle plume?) beneath the Archaean/Proterozoic lithosphere of the northern Baltic Shield that had been recently metasomatised. Melting of the carbonated garnet peridotite mantle formed a spectrum of magmas including carbonatite, damkjernite, melilitite, melanephelinite and ultramafic lamprophyre. Pockets of phlogopite metasomatised lithospheric mantle also melted to form potassic magmas including kimberlite. Depth of melting, degree of melting and presence of metasomatic phases are probably the major factors controlling the precise composition of the primary melts formed

    Electromagnetic properties of ice coated surfaces

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    The electromagnetic scattering from ice coated structures is examined. The influence of ice is shown from a measurement standpoint and related to a simple analytical model. A hardware system for the realistic measurement of ice coated structures is also being developed to use in an existing NASA Lewis icing tunnel. Presently, initial measurements have been performed with a simulated tunnel to aid in the development

    13 Ways of Looking at the Body

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    This work was generated as part of Rex Veeder\u27s Survive and Thrive Writing Workshop

    Inherent-Structure Dynamics and Diffusion in Liquids

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    The self-diffusion constant D is expressed in terms of transitions among the local minima of the potential (inherent structure, IS) and their correlations. The formulae are evaluated and tested against simulation in the supercooled, unit-density Lennard-Jones liquid. The approximation of uncorrelated IS-transition (IST) vectors, D_{0}, greatly exceeds D in the upper temperature range, but merges with simulation at reduced T ~ 0.50. Since uncorrelated IST are associated with a hopping mechanism, the condition D ~ D_{0} provides a new way to identify the crossover to hopping. The results suggest that theories of diffusion in deeply supercooled liquids may be based on weakly correlated IST.Comment: submitted to PR

    From/To: Gerald E. Beard (Chalk\u27s reply filed first)

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    The Levite\u27s Concubine: A Victim\u27s Fascination with Her Enslavement

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    In 1864, the Contagious Diseases Acts were passed by Parliament in Britain. They attempted to put a stop to the rampant disease which accompanied prostitution. The central figure in this law was the prostitute and the fallen woman. On one hand, the Contagious Diseases Acts of 1864 viewed prostitutes as commodities in a capitalistic society, and her fallen body was considered to be the source for her identity. On the other hand, opposing groups led by figures such as Josephine Butler sought to give fallen women a more natural identity which focused less on her body and more on her transcendent ability to self-determine. This thesis describes the debates about the Contagious Diseases Acts, Thomas Hardy’s Tess of the d’Urbervilles, and Elizabeth Barrett Browning’s Aurora Leigh as texts which frame and determine the course of debates about the place of fallen women in Victorian society

    Five Under the Eighth: Methodology Review and the Cruel and Unusual Punishments Clause

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    Five Under the Eighth: Methodology Review and the Cruel and Unusual Punishments Clause

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