76,773 research outputs found

    Organic chemical signatures of New Zealand carbonate concretions and calcite fracture fills as potential fluid migration indicators

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    Macroscopic calcite crystals are common in sedimentaÂŹry strata, occurring both as tectonic veins and also filling one or more generations of septarian rupture or later brittle fractures in calcareous concretions. Traces of hydrocarbons are frequently present in calcite crystals, especially near active petroleum systems, and are routinely the object of fluid inclusion studies linking source and migration pathway. Such calcites are shown here also to contain fatty acids in widely varying amounts ranging from 0.2 to more than 5 ÎŒg/g. Vein calcites examined are typically near the lower figure, close to analytical blank levels, and this is also true of some concretionary fracture fill calcites, notably those from the Palaeocene Moeraki ‘boulders’. Other concretionary fracture fill calcites (Jurassic, Scotland; Eocene, Waikato Coal Measures and associated marine strata) have much higher fatty acid contents, especially those filling later brittle style fractures. Although usually less abundant than the fatty acids in the concretions themselves, they lack the long chain n-acids derived from terrestrial vegetation and are commonly dominated by dioic acids. Exceptionally, in the calcitic septarian fill of a sideritic Coal Measures concretion, their abundance far exceeds that of concretion body fatty acids. They appear to be fluid transported, probably in aqueous solution, and have molecular signatures potentially distinctive of maturing organic matter sources from which the fluids derived

    Guide to the nature and methods of analysis of the clay fraction of tephras from the South Auckland region, New Zealand.

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    The manual outlines some of the more common laboratory procedures available for qualitatively and quantitatively analysing the composition of the tephric clays, many of which are difficult to determine because of their short range order or 'amorphous' nature. Techniques described and assessed in terms of their rapidity and quantitativeness include XRD, IR, DTA, TEM and SEM, sodium fluoride reactivity, chemical dissolution analyses, and surface area measurements. No one technique alone produces a definitive clay fraction analysis of tephric deposits. -from Author

    2,4-D and Mycoleptodiscus terrestris for control of Eurasian Watermilfoil

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    Growth chamber studies were conducted to evaluate the impact of an indigenous fungal pathogen, Mycoleptodiscus terrestris (Gerd.) Ostazeski, and the herbicide 2,4-D applied alone and in combination with one another, on the growth of a nuisance submersed plant, Eurasian watermilfoil ( Myriophyllum spicatum L.)(PDF has 6 pages.

    Gravitational wave searches using the DSN (Deep Space Network)

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    The Deep Space Network Doppler spacecraft link is currently the only method available for broadband gravitational wave searches in the 0.01 to 0.001 Hz frequency range. The DSN's role in the worldwide search for gravitational waves is described by first summarizing from the literature current theoretical estimates of gravitational wave strengths and time scales from various astrophysical sources. Current and future detection schemes for ground based and space based detectors are then discussed. Past, present, and future planned or proposed gravitational wave experiments using DSN Doppler tracking are described. Lastly, some major technical challenges to improve gravitational wave sensitivities using the DSN are discussed

    The Quantum Modular Group in (2+1)-Dimensional Gravity

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    The role of the modular group in the holonomy representation of (2+1)-dimensional quantum gravity is studied. This representation can be viewed as a "Heisenberg picture", and for simple topologies, the transformation to the ADM "Schr{\"o}dinger picture" may be found. For spacetimes with the spatial topology of a torus, this transformation and an explicit operator representation of the mapping class group are constructed. It is shown that the quantum modular group splits the holonomy representation Hilbert space into physically equivalent orthogonal ``fundamental regions'' that are interchanged by modular transformations.Comment: 23 pages, LaTeX, no figures; minor changes and clarifications in response to referee (basic argument and conclusions unaffected

    Obituary − Emeritus Professor Dr John Davidson McCraw (1925−2014) MBE, MSc NZ, DSc Well, CRSNZ, FNZSSS.

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    John McCraw was an Earth scientist who began working as a pedologist with Soil Bureau, DSIR, then became the Foundation Professor of Earth Sciences at the University of Waikato in Hamilton, inspiring a new generation to study and work in Earth sciences . In retirement, John McCraw was an author and historian with a special emphasis on Central Otago as well as the Waikato region. Throughout his career, marked especially by exemplary leadership, accomplished administration, and commitment to his staff and students at the University of Waikato, John McCraw also contributed to the communities in which he lived through public service organizations and as a public speaker. He received a number of awards including an MBE, fellowship, and companionship, and, uniquely, is commemorated also with a glacier, a fossil, and a museum-based research room named for him. Emeritus Professor John McCraw passed away on the 14th of December, 2014. An obituary, entitled “Dedicated to earth science and his students”, was published in the Waikato Times on the 10th of January, 2015

    Comparative Quantizations of (2+1)-Dimensional Gravity

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    We compare three approaches to the quantization of (2+1)-dimensional gravity with a negative cosmological constant: reduced phase space quantization with the York time slicing, quantization of the algebra of holonomies, and quantization of the space of classical solutions. The relationships among these quantum theories allow us to define and interpret time-dependent operators in the ``frozen time'' holonomy formulation.Comment: 24 pages, LaTeX, no figure
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