28,166 research outputs found

    Gold and palladium as indicators of an extraterrestrial component in the Cetaceous/Tertiary boundary layer at Woodside Creek and Chancet Quarry, Marlborough, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Earth Sciences at Massey University

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    It is widely believed that a large meteorite approximately 10 km in diameter impacted Earth at the termination of the Cretaceous Period with cosmic velocity, vaporising itself, along with a greater mass of the terrestrial target rocks into a cloud of hot rock vapour. The vapour cloud condensed into particles of sand to clay size at high altitude before returning to Earth to form a worldwide layer marking the Cretaceous/Tertiary boundary. Chemical evidence from this boundary layer suggests that the impactor was a chondritic meteorite, enriched in the platinum group elements compared to the Earth's crust. An enrichment of these elements above their background crustal abundances to approximately 0.1 of the chondritic abundance has been observed in a number of Cretaceous/Tertiary boundary layers worldwide. Iridium is the platinum group element traditionally used as an indicator of the extraterrestrial component (ETC) in likely impact layers due to its rarity in the Earth's crust and low detection limits possible using neutron activation analysis methods. Neutron activation analysis is however expensive and requires specialist facilities, this thesis proposes that the elements gold and palladium can also be used to indicate the ETC in the Cretaceous/Tertiary boundary layer. Samples from two Cretaceous/Tertiary boundary sites, Woodside Creek and Chancet Quarry, were analysed for gold and palladium using graphite furnace atomic absorption spectrometry. A strong correlation was found between iridium, gold, and palladium abundances at these sites, with all showing enrichment at precisely the Cretaceous/Tertiary boundary in proportion to iridium, indicating a common origin for all three elements. Gold showed almost precisely the expected 0.1 of its chondritic abundance in the clay size fraction at both Woodside Creek and Chancet Quarry (15 ng/g). Palladium showed exactly 0.1 of its chondritic abundance at the Chancet Quarry boundary with 53 ng/g. Gold abundances on the boundary at Woodside Creek (55 ng/g) and Chancet Quarry (44 ng/g) showed excellent agreement with published values as did the palladium result for Woodside Creek (22 ng/g)

    Information and ideas : concept design in three industrial contexts

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    This paper reviews the application of a new concept design method in a number of industrial settings. The ICR Grid is intended to better integrate information into the concept design process. In addition to sketching and sharing concepts in a manner similar to the 6-3-5 Method, participants undertake information search tasks, use specific information items for concept development, and reflect on the merit of concepts as the session progresses. Three different companies were invited to utilise the method to address current design issues. Grid output, observation and semi-structured interviews were used to assess the performance of the method, with marked differences in use across organisations highlighting future potential applications and development

    Digital information support for concept design

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    This paper outlines the issues in effective utilisation of digital resources in conceptual design. Access to appropriate information acts as stimuli and can lead to better substantiated concepts. This paper addresses the issues of presenting such information in a digital form for effective use, exploring digital libraries and groupware as relevant literature areas, and argues that improved integration of these two technologies is necessary to better support the concept generation task. The development of the LauLima learning environment and digital library is consequently outlined. Despite its attempts to integrate the designers' working space and digital resources, continuing issues in library utilisation and migration of information to design concepts are highlighted through a class study. In light of this, new models of interaction to increase information use are explored

    INSTITUTIONS AND THE VICIOUS CIRCLE OF DISTRUST IN THE RUSSIAN HOUSEHOLD DEPOSIT MARKET, 1992-1999

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    In our analysis of the Russian household deposit market during the 1990s, we show how the initial conditions of market emergence contributed to a vicious circle in which private commercial banks progressively lost the trust of potential depositors. The roots of this destructive dynamic lay in the initial conditions of market emergence. Initial experiences of fraud and financial loss led Russian households to distrust that commercial banks would honor their contractual obligations. As distrust grew and became more ingrained, the competitive conditions in the deposit market changed in a way that further increased the gains to opportunism and decreased the returns to trust production. In a self-reinforcing process, fraud begat more fraud.http://deepblue.lib.umich.edu/bitstream/2027.42/39974/3/wp588.pd

    A Guide to Disability Statistics from the 2000 Decennial Census

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    This User Guide addresses disability data available in the 2000 Decennial Census. A decennial census of the United States is conducted every ten years to provide statistics at the national, state, and local levels. The short form of the decennial census collects basic demographic data from five out of six households, and the long form collects the same basic demographic data, plus social and economic data from the remaining one in six households. Data are also collected from group quarters (GQ), which include individuals living in institutions, a population that is rarely included in surveys. The primary purpose of the demographic data is to draw Congressional districts. The social and economic data from the long form is especially valuable because it provides social and economic statistics for small geographic areas (such as counties, towns, and Congressional districts) that are estimated in a uniform manner across the United States. The Census 2000 long form included six questions that are used to identify the population with disabilities. These data can be extremely useful to disability policymakers, disability service providers, and the disability advocacy community. This User Guide discusses the variety of information on disability, demographic characteristics, employment, and economic well-being available from Census 2000 long form data

    INSTITUTIONS AND THE VICIOUS CIRCLE OF DISTRUST IN THE RUSSIAN HOUSEHOLD DEPOSIT MARKET, 1992-1999

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    In our analysis of the Russian household deposit market during the 1990s, we show how the initial conditions of market emergence contributed to a vicious circle in which private commercial banks progressively lost the trust of potential depositors. The roots of this destructive dynamic lay in the initial conditions of market emergence. Initial experiences of fraud and financial loss led Russian households to distrust that commercial banks would honor their contractual obligations. As distrust grew and became more ingrained, the competitive conditions in the deposit market changed in a way that further increased the gains to opportunism and decreased the returns to trust production. In a self-reinforcing process, fraud begat more fraud.

    Dark Nuclei I: Cosmology and Indirect Detection

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    In a companion paper (to be presented), lattice field theory methods are used to show that in two-color, two-flavor QCD there are stable nuclear states in the spectrum. As a commonly studied theory of composite dark matter, this motivates the consideration of possible nuclear physics in this and other composite dark sectors. In this work, early Universe cosmology and indirect detection signatures are explored for both symmetric and asymmetric dark matter, highlighting the unique features that arise from considerations of dark nuclei and associated dark nuclear processes. The present day dark matter abundance may be composed of dark nucleons and/or dark nuclei, where the latter are generated through it dark nucleosynthesis. For symmetric dark matter, indirect detection signatures are possible from annihilation, dark nucleosynthesis, and dark nuclear capture and we present a novel explanation of the galactic center gamma ray excess based on the latter. For asymmetric dark matter, dark nucleosynthesis may alter the capture of dark matter in stars, allowing for captured particles to be processed into nuclei and ejected from the star through dark nucleosynthesis in the core. Notably, dark nucleosynthesis realizes a novel mechanism for indirect detection signals of asymmetric dark matter from regions such as the galactic center, without having to rely on a symmetric dark matter component.Comment: 31 pages, 9 figure

    Dark Nuclei II: Nuclear Spectroscopy in Two-Colour QCD

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    We consider two-colour QCD with two flavours of quarks as a possible theory of composite dark matter and use lattice field theory methods to investigate nuclear spectroscopy in the spin J=0J=0 and J=1J=1 multi-baryon sectors. We find compelling evidence that J=1J=1 systems with baryon number B=2,3B=2,3 (and their mixed meson-baryon counterparts) are bound states - the analogues of nuclei in this theory. In addition, we estimate the σ\sigma-terms of the J=0J=0 and J=1J=1 single baryon states which are important for the coupling of the theory to scalar currents that may mediate interactions with the visible sector.Comment: 40 pages, 26 figure
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