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- Department of Earth and Environmental Sciences (9)
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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Multiproxy Lake Sediment Records At The Northern And Southern Boundaries Of The Aspen Parkland Region Of Manitoba, Canada, Rebecca Teed, Charles Umbanhower, Philip Camill
Multiproxy Lake Sediment Records At The Northern And Southern Boundaries Of The Aspen Parkland Region Of Manitoba, Canada, Rebecca Teed, Charles Umbanhower, Philip Camill
Earth and Environmental Sciences Faculty Publications
Aspen parkland in central Canada may change substantially with increased warming and aridity as prairies replace forests, fire return intervals decrease and lake levels decline. We examined the relationships among vegetation, climate, fire and lake-ecosystem properties using lake sediment cores from the current northern and southern boundaries of the aspen parkland in southwestern Manitoba. We analyzed pollen, charcoal, sediment magnetics, biogenic silica, phosphorus, grain size and LOI, and dated the cores using 210Pb and 14C (AMS, calibrated). The Jones Lake record, from the southern edge of the parkland, began considerably earlier (~11 000 cal. BP) than the Mallard …
Strain Waves, Earthquakes, Slow Earthquakes, And Afterslip In The Framework Of The Frenkel-Kontorova Model, Naum I. Gershenzon, V. G. Bykov, Gust Bambakidis
Strain Waves, Earthquakes, Slow Earthquakes, And Afterslip In The Framework Of The Frenkel-Kontorova Model, Naum I. Gershenzon, V. G. Bykov, Gust Bambakidis
Physics Faculty Publications
The one-dimensional Frenkel-Kontorova (FK) model, well known from the theory of dislocations in crystal materials, is applied to the simulation of the process of nonelastic stress propagation along transform faults. Dynamic parameters of plate boundary earthquakes as well as slow earthquakes and afterslip are quantitatively described, including propagation velocity along the strike, plate boundary velocity during and after the strike, stress drop, displacement, extent of the rupture zone, and spatiotemporal distribution of stress and strain. The three fundamental speeds of plate movement, earthquake migration, and seismic waves are shown to be connected in framework of the continuum FK model. The …
Eco-Epidemiological Analysis For Screening-Level Ecological Risk Assessment: A Geographic Information Systems Approach, Katherine E. Kapo
Eco-Epidemiological Analysis For Screening-Level Ecological Risk Assessment: A Geographic Information Systems Approach, Katherine E. Kapo
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The identification and prioritization of multiple watershed stressors and the corresponding development of optimal management strategies remains a challenge in ecological risk assessment. Eco-epidemiological analysis of archival environmental spatial databases integrates available biological, physical and chemical information to generate hypotheses based on stressor-response data relationships. A geographic information systems-based technique incorporating Bayesian weights-of-evidence analysis and weighted logistic regression (WOE/WLR) developed for and currently utilized in minerals exploration was extrapolated to the eco-epidemiological analysis of aquatic ecosystem data. Case studies within state of Ohio (USA) and England and Wales were conducted to demonstrate a method proof-of-concept in the context of various …
Conservation Genetics Of A Near Threatened Freshwater Mussel Species (Lampsilis Cardium) And Improved Prospects For Recovery: How Nuclear And Mitochondrial Dna Analyses Inform Natural History And Conservation, Chad D. Ferguson
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Freshwater mussels (Bivalvia: Unionidae) are among the most imperiled organisms in North America. While there is an urgent need for effective conservation planning and management of these organisms, important basic biological information is lacking. This research characterizes levels of genetic diversity and population structure in the Near Threatened (IUCN) freshwater mussel Lampsilis cardium in populations from Twin Creek (southwest Ohio), Little Darby and Big Darby Creeks (central Ohio), and Little Muskingum River (eastern Ohio) and assesses the extent to which regional geological events explain population structuring. Data from the congener Lampsilis ovata from Clinch River (Tennessee) are included for comparison. …
Linking Plume Spreading To Hierarchical Stratal Architecture, Ramya Ramanathan
Linking Plume Spreading To Hierarchical Stratal Architecture, Ramya Ramanathan
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A new form of the Lagrangian-based model for macrodispersion of inert (non-reactive) solutes is presented. The model is based on a hierarchical expression of the spatial covariance of log-permeability representing a hierarchy of stratal unit types with a corresponding hierarchy of permeability subpopulations. The covariance expression representing the hierarchy of unit types is a linear sum of terms corresponding to the probability of transitioning across stratal unit types of different scales, and these terms are directly related to quantifiable geometric attributes of the hierarchical stratal architecture. The new macrodispersion model is also a linear sum of terms, with different integral …
Using Morphometrics, Phylogenetic Systematics And Parsimony Analysis To Gain Insight Into The Evolutionary Affinities Of The Calymenidae Trilobita, Alex J. Chestnut
Using Morphometrics, Phylogenetic Systematics And Parsimony Analysis To Gain Insight Into The Evolutionary Affinities Of The Calymenidae Trilobita, Alex J. Chestnut
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The most common trilobite in the Silurian carbonates of Ohio - especially the Springfield Dolomite - is a species that has been assigned to at least five genera over the past 100 years. This trilobite has been variously referred to as Calymene celebra, Apocalymene celebra, Flexicalymene celebra, Gravicalymene celebra, and Sthenarocalymene celebra. Reexamination of the species "Calymene" celebra through parsimony and morphometric analysis was conducted to properly place this calymenid species within the correct genus. What compounds the confusion is that the characters used to seperate the genera within the family Calymenidae, and therefore create the basis for the argument …
The Continuity Of High-Permeability Zones In Sedimentary Deposits, Arijit Guin
The Continuity Of High-Permeability Zones In Sedimentary Deposits, Arijit Guin
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Cubic lattice models were used to represent sedimentary deposits and their role as georeservoirs. The percolation of high-permeability zones was studied using both analytical and simulation approaches. The analytical approach was developed for single-scale sedimentary architecture. The approach showed that percolation is affected by cluster spatial correlation and by lattice size. It showed that correlation affects both high-permeability and low-permeability clusters equally, and thus correlation does not likely affect the percolation threshold for infinite lattices. On finite lattices, the analysis showed that the effect of correlation on lowering the percolation threshold can be understood through the truncation of low-permeability cluster-size …
Porosity And Permeability In Ternary Sediment Mixtures, Jason Dennis Esselburn
Porosity And Permeability In Ternary Sediment Mixtures, Jason Dennis Esselburn
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Porosity and permeability were measured in mixtures of fine, medium, and coarse sand, where the volume fraction of each of the three components was systematically varied. The porosity varies non-linearly with the volume fractions, and can be modeled with a piecewise-linear approach. The permeability also varies non-linearly with the volume fractions. Permeability can be modeled with the Kozeny-Carman equation using a recursive approach for computing the representative grain size from those of the components in the mixture.
Measuring The Permeability Of Open-Framework Gravel, James Thomas Ferreira Jr.
Measuring The Permeability Of Open-Framework Gravel, James Thomas Ferreira Jr.
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Open-framework gravel has permeability, k, above the measurement range of most conventional constant-head permeameters used in laboratories. Here I addressed the challenge of measuring such high k by using a permeameter long enough that the differences in head across it were on the order of 10-3 m and therefore measurable. I collected data over the range from linear-laminar flow to non-linear, non-Darcian flow. In doing so, I verified that k was measured under Darcian flow. I measured k between 4,000 and 100,000 Darcies among experiments using different sediments.
A Morphometric Analysis Of The Highly Variable Clypeasteroid, Periarchus Lyelli, Lauren Elizabeth Williamson
A Morphometric Analysis Of The Highly Variable Clypeasteroid, Periarchus Lyelli, Lauren Elizabeth Williamson
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The Late Eocene echinoid, Periarchus lyelli (Conrad, 1834), known for its wide geographic range, high abundance, and specific stratigraphic range, is an ideal example of a guide fossil. However, due to its highly variable test morphology, many have questioned if, in fact, this sand dollar is actually two or three distinct species that have been misclassified. A preliminary study on this subject has been performed on specimens from Mississippi, North Carolina and South Carolina (Williamson, 2006), showing significant separation in test shapes. Continuing previous research, this study analyzes the test shapes of P. lyelli over its entire North American geographic …
Bench-Scale Conversion Of Carbon Dioxide To A Hydrocarbon Fuel, Melissa L. Kennedy
Bench-Scale Conversion Of Carbon Dioxide To A Hydrocarbon Fuel, Melissa L. Kennedy
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There is a growing concern about the effects of global warming that many believe is anthropogenically caused. As such, scientists are trying to uncover a viable alternative fuel source and establish a way to reduce atmospheric carbon dioxide levels. A potential solution that addresses both of these aspects would be to capture atmospheric carbon dioxide and convert it into a natural gas, in particular methane, which could be used as an energy source. A laboratory-scale experiment using 6 160 mL microcosms (3 with anaerobic wetland soil and 3 relatively soil free) and 2 7.2 L bioreactors was conducted to learn …