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  • 1
    Electronic Resource
    Electronic Resource
    The conductivity of the crust and mantle beneath the Kapuskasing Uplift: electrical anisotropy in the upper mantle (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 113 (1993), S. 0 
    Details
    ISSN: 1365-246X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: The Kapuskasing Uplift has been interpreted as an oblique cross-section of up to 25 km of crust and thus provides the opportunity to examine the properties of exposed mid- to lower-crustal material. A magnetotelluric (MT) survey mapped a remarkably uniform upper crust and provided no evidence for upper crustal conductive zones that could be related to the often observed increase in mid and lower crustal conductivity. The only shallow conductive anomaly is related to the Ivanhoe Lake Cataclastic Zone but its electrical signature does not appear to extend more than one kilometer in depth.A regional apparent resistivity curve was determined from MT data and confirmed by subsequent controlled source electromagnetic surveys. Regional curves are essential for proper structural interpretation but are often difficult to determine because of electric field distortions. The data show a decrease in resistivity at depths below 15 km which is typical of continental crust in many areas of the world.There is a clear difference in orthogonal apparent resistivity and phase curves at periods greater than 10 s which is most pronounced in a N65d̀E and N25d̀W coordinate frame. Two different models are proposed to explain the data. The first consists of a conducting 2-D slab of approximately 50 km width in the lower crust and striking N65d̀E. The strike direction is consistent with a number of regional structural trends but there is no other direct supporting evidence for it. The second model invokes either micro or macro electrical anisotropy in the upper mantle. There is considerable evidence for seismic anisotropy in the region. The electrical anisotropy could be the result of preferential conduction along the c-axis of olivine crystals, hydrogen dissolved in the olivine lattice with preferential conduction along the a-axis, or possible alignment of dykes, joints and faults in the upper mantle. If the anisotropy is related to strain induced orientations of crystals or fabric, it will provide evidence for the motions of the mantle associated with plate tectonics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-246X.1993.tb00901.x
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  • 2
    Electronic Resource
    Electronic Resource
    Ion-adsorbent substomatal structures in Tradescantia pallidus (1977)
    [s.l.] : Nature Publishing Group
    Nature 268 (1977), S. 364-365 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Tradescantia pallidus was selected as a more suitable material for further investigations into the form and function of substomatal ion-adsorbent sites because its stomata respond readily to physiological experimentation and it has well developed ion-adsorbent sites, as determined by the Macallum ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/268364a0
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  • 3
    Electronic Resource
    Electronic Resource
    New structure associated with stomatal complex of the fern Polypodium vulgare (1977)
    [s.l.] : Nature Publishing Group
    Nature 265 (1977), S. 331-334 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Using the basic Macallum stain4 and viewing the stained epidermal strip from the side adjacent to the mesophyll under a Zeiss Photomicroscope II, distinct polar accumulations of the ion can be observed in the guard-cell complexes (Fig. 1a). The accumulations are commonly up to 25 µm in ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/265331a0
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  • 4
    Electronic Resource
    Electronic Resource
    Did civil reactors supply plutonium for weapons? (2000)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 407 (2000), S. 833-834 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sir We welcome the recent publication by the UK Ministry of Defence (MOD) of the first official inventory of the country's military plutonium. The report contains a remarkable admission : “These figures show that the weapon cycle stockpile is in fact some 0.3 tonnes ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35038256
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  • 5
    Electronic Resource
    Electronic Resource
    Where has Britain's plutonium gone? (1998)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 395 (1998), S. 739-739 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SirThe UK government's Department of Trade and Industry has issued a document that claims to be “⃛part of the UK's renewed commitment to improve transparency and openness in its management of our national holding of civil plutonium”. In fact the new format ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/27304
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  • 6
    Electronic Resource
    Electronic Resource
    British civil plutonium: production and fate (1988)
    [s.l.] : Nature Publishing Group
    Nature 333 (1988), S. 709-710 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR-In 1985, we reported calculations of the size of the UK civil plutonium stock-pile from which we concluded that at least 2.3 ± 0.8 tonnes of plutonium (sufficient for 400 warheads) are unaccounted for1. We now confirm the accuracy of our cal-culations for more than half the total civil ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/333709a0
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  • 7
    Electronic Resource
    Electronic Resource
    Structural and functional aspects of stomata (1978)
    Springer
    Planta 142 (1978), S. 307-316 
    Details
    ISSN: 1432-2048
    Keywords: Cell walls ; Ontogeny, stomatal ; Polypodium ; Starch ; Stomata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Differential cell wall thickening in developing guard cells of Polypodium vulgare L. has been studied with particular reference to guard cell protoplast deformation and the eventual formation of the stomatal pore. Concomitant studies on the development of guard cell chloroplasts and their starch inclusions during ontogeny of the stomatal complex have provided data which have been incorporated into a model to account for the formation of the pore. Guard cell starch inclusions reach a maximum density per unit volume at the same time as the guard cell walls achieve maximum differential thickening. These events coincide with the development of the pore. It is suggested that, whilst pore formation is initiated enzymatically, the mechanical forces required to bring about the separation of the two guard cells are of an osmotic nature derived from starch hydrolysis. The development of the mesophyll in relation to the epidermis is examined in respect of the formation of substomatal chambers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00385082
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  • 8
    Electronic Resource
    Electronic Resource
    Isolation, identification and quantification by X-ray diffraction of carbide phases in 2 1/4Cr-1 Mo steel (1985)
    Springer
    Journal of materials science 20 (1985), S. 3631-3638 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The addition of controlled amounts of phosphorus to 2 1/4Cr-1 Mo steel, heat treated under two different conditions, has produced microstructures containing a wide spectrum of types and amounts of individual carbide phases. X-ray diffraction analysis of carbide precipitates has been undertaken following quantitative extraction by anodic dissolution of the matrix. By combining this with selective chemical dissolution of certain carbide types, calibrations of relative weight fractions against the intensities of suitable X-ray diffraction peaks may be obtained without the need for the addition of a standard calibration powder. This has allowed the determination of the absolute amounts, within a given steel sample, of the carbide types M6C, M7C3, M23C6 and, most importantly, the creep-strengthening M2X phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01113770
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