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  • Journal article
    Luong D, Court RW, Sims MR, Cullen DC, Sephton MAet al., 2014,

    Extracting organic matter on Mars: A comparison of methods involving subcritical water, surfactant solutions and organic solvents

    , Planetary and Space Science, Vol: 99, Pages: 19-27, ISSN: 0032-0633
  • Conference paper
    Shah J, Muxworthy AR, Russell S, Genge Met al., 2014,

    Magnetic remanence of l/ll4 Bjurböle: timing, intensity, and implications (poster)

    , 77th Annual Meteoritical Society Meeting
  • Journal article
    Kersten M, Xiao T, Kreissig K, Brett A, Coles BJ, Rehkaemper Met al., 2014,

    Tracing Anthropogenic Thallium in Soil Using Stable Isotope Compositions

    , ENVIRONMENTAL SCIENCE & TECHNOLOGY, Vol: 48, Pages: 9030-9036, ISSN: 0013-936X
  • Journal article
    Bridgestock LJ, Williams H, Rehkaemper M, Larner F, Giscard MD, Hammond S, Coles B, Andreasen R, Wood BJ, Theis KJ, Smith CL, Benedix GK, Schoenbaechler Met al., 2014,

    Unlocking the zinc isotope systematics of iron meteorites

    , EARTH AND PLANETARY SCIENCE LETTERS, Vol: 400, Pages: 153-164, ISSN: 0012-821X
  • Journal article
    Sephton MA, Carter JN, 2014,

    Statistics Provide Guidance for Indigenous Organic Carbon Detection on Mars Missions

    , Astrobiology, Vol: 14, Pages: 706-713, ISSN: 1531-1074

    <jats:p>Data from the Viking and Mars Science Laboratory missions indicate the presence of organic compounds that are not definitively martian in origin. Both contamination and confounding mineralogies have been suggested as alternatives to indigenous organic carbon. Intuitive thought suggests that we are repeatedly obtaining data that confirms the same level of uncertainty. Bayesian statistics may suggest otherwise. If an organic detection method has a true positive to false positive ratio greater than one, then repeated organic matter detection progressively increases the probability of indigeneity. Bayesian statistics also reveal that methods with higher ratios of true positives to false positives give higher overall probabilities and that detection of organic matter in a sample with a higher prior probability of indigenous organic carbon produces greater confidence. Bayesian statistics, therefore, provide guidance for the planning and operation of organic carbon detection activities on Mars. Suggestions for future organic carbon detection missions and instruments are as follows: (i) On Earth, instruments should be tested with analog samples of known organic content to determine their true positive to false positive ratios. (ii) On the mission, for an instrument with a true positive to false positive ratio above one, it should be recognized that each positive detection of organic carbon will result in a progressive increase in the probability of indigenous organic carbon being present; repeated measurements, therefore, can overcome some of the deficiencies of a less-than-definitive test. (iii) For a fixed number of analyses, the highest true positive to false positive ratio method or instrument will provide the greatest probability that indigenous organic carbon is present. (iv) On Mars, analyses should concentrate on samples with highest prior probability of indigenous organic carbon; intuitive desires to contrast samples of high prior probability and low
  • Journal article
    Sephton MA, 2014,

    Astrobiology can help space science, education and the economy

    , Space Policy, Vol: 30, Pages: 146-148, ISSN: 0265-9646
  • Journal article
    Murphy K, Rehkaemper M, van de Flierdt T, 2014,

    Comment on "The isotopic composition of cadmium in the water column of the South China Sea"

    , GEOCHIMICA ET COSMOCHIMICA ACTA, Vol: 134, Pages: 335-338, ISSN: 0016-7037
  • Journal article
    Muxworthy AR, Krasa D, Williams W, Almeida TPet al., 2014,

    Paleomagnetic recording fidelity of nonideal magnetic systems

    , GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, Vol: 15, Pages: 2254-2261, ISSN: 1525-2027
  • Journal article
    Crocket KC, Lambelet M, de Flierdt TV, Rehkaemper M, Robinson LFet al., 2014,

    Measurement of fossil deep-sea coral Nd isotopic compositions and concentrations by TIMS as NdO<SUP>+</SUP>, with evaluation of cleaning protocols

    , CHEMICAL GEOLOGY, Vol: 374, Pages: 128-140, ISSN: 0009-2541
  • Journal article
    Montgomery W, Watson JS, Sephton MA, 2014,

    An organic cosmo-barometer: Distinct pressure and temperature effects for methyl substituted polycyclic aromatic hydrocarbons

    , Astrophysical Journal, Vol: 784, ISSN: 0004-637X

    There are a number of key structures that can be used to reveal the formation and modification history of organic matter in the cosmos. For instance, the susceptibility of organic matter to heat is well documented and the relative thermal stabilities of different isomers can be used as cosmothermometers. Yet despite being an important variable, no previously recognized organic marker of pressure exists. The absence of a pressure marker is unfortunate considering our ability to effectively recognize extraterrestrial organic structures both remotely and in the laboratory. There are a wide variety of pressures in cosmic settings that could potentially be reflected by organic structures. Therefore, to develop an organic cosmic pressure marker, we have used state-of-the-art diamond anvil cell (DAC) and synchrotron-source Fourier transform infrared (FTIR) spectroscopy to reveal the effects of pressure on the substitution patterns for representatives of the commonly encountered methyl substituted naphthalenes, specifically the dimethylnaphthalenes. Interestingly, although temperature and pressure effects are concordant for many isomers, pressure appears to have the opposite effect to heat on the final molecular architecture of the 1,5-dimethylnaphthalene isomer. Our data suggest the possibility of the first pressure parameter or "cosmo-barometer" (1,5-dimethylnaphthalene/total dimethylnaphthalenes) that can distinguish pressure from thermal effects. Information can be obtained from the new pressure marker either remotely by instrumentation on landers or rovers or directly by laboratory measurement, and its use has relevance for all cases where organic matter, temperature, and pressure interplay in the cosmos. © 2014. The American Astronomical Society. All rights reserved.
  • Journal article
    Hettmann K, Kreissig K, Rehkaemper M, Wenzel T, Mertz-Kraus R, Markl Get al., 2014,

    Thallium geochemistry in the metamorphic Lengenbach sulfide deposit, Switzerland: Thallium-isotope fractionation in a sulfide melt

    , AMERICAN MINERALOGIST, Vol: 99, Pages: 793-803, ISSN: 0003-004X
  • Journal article
    Bray VJ, Collins GS, Morgan JV, Melosh HJ, Schenk PMet al., 2014,

    Hydrocode simulation of Ganymede and Europa cratering trends - How thick is Europa's crust?

    , ICARUS, Vol: 231, Pages: 394-406, ISSN: 0019-1035
  • Journal article
    Larner F, Gulson B, McCall M, Oytam Y, Rehkaemper Met al., 2014,

    An inter-laboratory comparison of high precision stable isotope ratio measurements for nanoparticle tracing in biological samples

    , JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY, Vol: 29, Pages: 471-477, ISSN: 0267-9477
  • Journal article
    Hettmann K, Marks MAW, Kreissig K, Zack T, Wenzel T, Rehkaemper M, Jacob DE, Markl Get al., 2014,

    The geochemistry of Tl and its isotopes during magmatic and hydrothermal processes: The peralkaline Ilimaussaq complex, southwest Greenland

    , CHEMICAL GEOLOGY, Vol: 366, Pages: 1-13, ISSN: 0009-2541
  • Conference paper
    Almeida TP, Muxworthy AR, Williiams W, Kasama T, Dunin-Borkowski Ret al., 2014,

    Hydrothermal synthesis, off-axis electron holography and magnetic properties of Fe3O4 nanoparticles
  • Journal article
    Fraser WT, Watson JS, Sephton MA, Lomax BH, Harrington G, Gosling WD, Self Set al., 2014,

    Changes in spore chemistry and appearance with increasing maturity

    , Review of Palaeobotany and Palynology, Vol: 201, Pages: 41-46, ISSN: 0034-6667
  • Conference paper
    Roberts O, Muxworthy AR, Mac Niocaill C, Døssing Aet al., 2014,

    High-latitude paleomagnetic and Ar-Ar study of 0-6 Ma lavas from eastern Iceland: Contribution to the time-averaged field initiative (poster)

    , Magnetic Interactions
  • Conference paper
    Lam C, Muxworthy AR, Green D, 2014,

    Determining the magnetic signature of London’s air pollution (poster)

    , Magnetic Interactions
  • Conference paper
    Emmerton S, Muxworthy AR, 2014,

    Correlating biodegradation to magnetisation in oil bearing sedimentary rocks (poster)

    , Magnetic Interactions
  • Conference paper
    Emmerton S, Muxworthy AR, Sephton MA, 2014,

    Dating hydrocarbon seeps – the Mupe Bay Mystery (poster)

    , Magnetic Interactions

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