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Articles 49801 - 49830 of 59446
Full-Text Articles in Entire DC Network
Three-Dimensional Modeling Of Lacustrine Diatom Habitat Areas: Improving Paleolimnological Interpretation Of Planktic : Benthic Ratios, Jeffery R. Stone, Sherilyn C. Fritz
Three-Dimensional Modeling Of Lacustrine Diatom Habitat Areas: Improving Paleolimnological Interpretation Of Planktic : Benthic Ratios, Jeffery R. Stone, Sherilyn C. Fritz
Department of Earth and Atmospheric Sciences: Faculty Publications
Three-dimensional modeling of lake morphometry enables the calculation of lake volume, planar surface area, and basin surface area, which are critical components of a conceptual model of how planktic and benthic habitat areas change with changing lake level. We have applied three-dimensional modeling to Foy Lake, Montana, and compared model results of changing ratios of planktic and benthic habitat areas at all possible lake levels to sediment cores recovered from the lake. The model allows us to produce semiquantitative depth reconstructions and greatly improves lake-level reconstruction of this morphometrically complex basin. The conceptual model also was modified to examine the …
An Unusually Large Aulocopella Winnipegensis And Associated Demosponges From The Upper Ordovician Beaverfoot Formation, Southeastern British Columbia, J. Keith Rigby, Paul A. Johnston
An Unusually Large Aulocopella Winnipegensis And Associated Demosponges From The Upper Ordovician Beaverfoot Formation, Southeastern British Columbia, J. Keith Rigby, Paul A. Johnston
Faculty Publications
An unusually large specimen of the rare digitate to bladed Aulocopella winnipegensis Rauff and three relatively normal sized specimens of ashtray-shaped Hudsonospongia? sp. constitute the first record of demosponges from the Upper Ordovician Beaverfoot Formation in southeastern British Columbia and the first record of these taxa from western Canada. Gross form and canal structure are well preserved, but dolomitization and (or) coarse microsphaeroidal silicification have obliterated spicules and other structural details. We interpret these sponges as epifaunal recliners, without means of attachment to the substrate, a life mode rarely encountered in the modern sponge biota.
Seismic Expression Of Pleistocene Paleoceanographic Changes In The California Borderland From Digitally Acquired 3.5 Khz Subbottom Profiles And Ocean Drilling Program Leg 167 Drilling, Aleksandra Janik, Mitchell W. Lyle, Lee M. Liberty
Seismic Expression Of Pleistocene Paleoceanographic Changes In The California Borderland From Digitally Acquired 3.5 Khz Subbottom Profiles And Ocean Drilling Program Leg 167 Drilling, Aleksandra Janik, Mitchell W. Lyle, Lee M. Liberty
CGISS Publications and Presentations
We correlate processed 3.5 kHz seismic profiles with physical properties of cores collected during ODP Leg 167 from the Tanner, East Cortes, and San Nicolas Basins through much of the Pleistocene succession. Results indicate that seismic horizons in the unconsolidated Pleistocene sediments (top 50 m) are mainly controlled by density contrasts. Removing of the compaction trend from the density reveals a very interesting relationship between density and composition - the density closely and inversely correlates with organic carbon indicating that large-scale variations in organic carbon are responsible for seismic reflections through their influence on density. This is a significant discovery …
Lower Yilgarn Catchment Appraisal 2003, D G. Cummins
Lower Yilgarn Catchment Appraisal 2003, D G. Cummins
Resource management technical reports
This report summarises current information on risks and impacts to agricultural production and natural resources within the Lower Yilgarn Catchment. It also identifies suitable options to manage such risks. The report has been divided into three sections : the natural resource base, the catchment risks and management options and impacts. Rapid Catchment Appraisal aims to document salinity risk and management options by addressing all threats to the natural resource base.
Classifying Mollisol Soils Using Hyperspectral Remote Sensing Data, Adil M. Wadia
Classifying Mollisol Soils Using Hyperspectral Remote Sensing Data, Adil M. Wadia
All-Inclusive List of Electronic Theses and Dissertations
Soil classification is a complex task that involves several factors. Soil classifications that have been published usually need to be updated as soil series definitions and boundaries change over time. Most existing soil classification surveys in the United States, although often very good, lack the required accuracy for selected applications such as precision agriculture. 111 Hyperspectral remote sensing data, with its 100+ bands and very high spectral resolution can help facilitate soil classification detail not achieved through traditional remote sensing methods. The study area selected for research was Wolf Field, near Homer, Champaign County, Illinois, which is a very agriculturally …
Accuracy Of Neural Network Classifiers In Humid Tropical Areas, Genong Yu
Accuracy Of Neural Network Classifiers In Humid Tropical Areas, Genong Yu
All-Inclusive List of Electronic Theses and Dissertations
This research develops a better understanding of the use of neural networks in the context of tropical land cover characterization using multiple scale remotely sensed data. Results of the research contributed to developing a robust neural network classifier suitable to use for humid tropical land cover classification in areas such as Altamira, Brazil. Research was focused upon the following: (1) performance ofneural networks with different ancillary data- such as DEM (digital elevation model) and its derivatives; (2) effect of spatial scale on neural network classifiers using remote sensing data from IKONOS, Landsat TM, ASTER, and MODIS; (3) accuracy of neural …
Mesopredator Movement, Abundance, And Habitat Selection In The Rainwater Basins Of Nebraska, Christina J. Kocer
Mesopredator Movement, Abundance, And Habitat Selection In The Rainwater Basins Of Nebraska, Christina J. Kocer
School of Natural Resources: Dissertations, Theses, and Student Research
No abstract provided.
Efficacy Of Offshore Breakwater Structures In A Eutrophic Midwestern Reservoir, Larry D. Pape
Efficacy Of Offshore Breakwater Structures In A Eutrophic Midwestern Reservoir, Larry D. Pape
School of Natural Resources: Dissertations, Theses, and Student Research
No abstract provided.
Experimental Investigation Of Time Dependent Behavior Of Welded Topopah Spring Tuff, Lumin Ma
Experimental Investigation Of Time Dependent Behavior Of Welded Topopah Spring Tuff, Lumin Ma
Publications (YM)
Four types of laboratory tests have been performed. Specimens were attained from four lithophysal zones of the welded Topopah Spring Tuff unit at Yucca Mountain, Nevada: upper lithophysal, middle nonlithophysal, lower lithophysal and lower nonlithophysal zones. Two types of tests are conducted to study time-dependent behavior: constant strain rate and creep tests. Sixty five specimens from the middle nonlithophysal zone were tested at six strain rates: 10 , 10 , 10 , 10 , 10 , and 10 . Test durations range from 2 seconds to 7 days. Fourteen specimens from middle nonlithophysal, lower lithophysal and lower nonlithophysal zones are …
Impact Of Heterogeneity, Bed Forms, And Stream Curvature On Subchannel Hyporheic Exchange, M. Bayani Cardenas, J. L. Wilson, Vitaly A. Zlotnik
Impact Of Heterogeneity, Bed Forms, And Stream Curvature On Subchannel Hyporheic Exchange, M. Bayani Cardenas, J. L. Wilson, Vitaly A. Zlotnik
Department of Earth and Atmospheric Sciences: Faculty Publications
Advection through hyporheic zones (HZ) consisting of heterogeneous channel bend streambed deposits and their equivalent homogenous medium was investigated using finite difference groundwater flow and transport simulations and forward particle tracking. The top prescribed head boundary was varied in order to mimic various stream channel head distributions resulting from the presence of bed forms and channel curvature. Flux calculations show that heterogeneity causes significant additional HZ flux compared to an equivalent homogenous medium. However, the major cause of HZ flux is a spatially periodic (sinusoidal) head distribution along the boundary, representing the effect of bed forms. The additional influence of …
Space-Based Measurements Of Sheet Flow Characteristics In The Everglades, Wetland, Florida, Shimon Wdowinski, Falk Amelung, Fernando Miralles-Wilhelm, Timothy H. Dixon, Richard Carande
Space-Based Measurements Of Sheet Flow Characteristics In The Everglades, Wetland, Florida, Shimon Wdowinski, Falk Amelung, Fernando Miralles-Wilhelm, Timothy H. Dixon, Richard Carande
School of Geosciences Faculty and Staff Publications
New space-based observations of South Florida with interferometric SAR (InSAR) reveal spatially detailed, quantitative images of water levels in the Everglades. The new data capture dynamic water level topography, providing the first detailed picture of wetland sheet flow. We observe localized radial sheet flow in addition to well-known southward unidirectional sheet flow, modelled as a linear diffusive flow. We obtain quantitative estimates of flow diffusivity (23–91 m2/s), the first space-based estimates of such hydrologic parameter for the Everglades. Space-based hydrologic observations can provide critical information for monitoring, understanding and managing wetland sheet flow, and contribute to wetland restoration.
Willamette River Basin Temperature Tmdl Model: Model Calibration, Chris Berger, Michael Lee Mckillip, Robert Leslie Annear, Sher Jamal Khan, Scott A. Wells
Willamette River Basin Temperature Tmdl Model: Model Calibration, Chris Berger, Michael Lee Mckillip, Robert Leslie Annear, Sher Jamal Khan, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and …
Systematics And Phylogeny Of Late Paleocene And Early Eocene Palaeoryctinae (Mammalia, Insectivora) From The Clarks Fork And Bighorn Basins, Wyoming, Jonathan I. Bloch, Ross Secord, Philip D. Gingerich
Systematics And Phylogeny Of Late Paleocene And Early Eocene Palaeoryctinae (Mammalia, Insectivora) From The Clarks Fork And Bighorn Basins, Wyoming, Jonathan I. Bloch, Ross Secord, Philip D. Gingerich
Department of Earth and Atmospheric Sciences: Faculty Publications
New specimens of Palaeoryctes punctatus from the middle Clarkforkian of the Clarks Fork Basin include a left dentary preserving the crowns of I1-C1, P3, and M1-2, with alveoli for P2, P4, and M3. The lower dental formula, previously unknown for this species, is 3.1.3.3. A maxillary fragment preserves the crowns of a broken P4, complete M1, and a broken M2. Specimens previously referred to Palaeoryctes cf. P. punctatus and cf. Palaeoryctes sp. from the late Tiffanian are morphologically distinct and …
Volatile Light Hydrocarbons In Geothermal Gas Emissions From Yellowstone National Park, Usa, And Comparisons To El Salvador And Honduras, Bethany Burnett
Volatile Light Hydrocarbons In Geothermal Gas Emissions From Yellowstone National Park, Usa, And Comparisons To El Salvador And Honduras, Bethany Burnett
Earth and Planetary Sciences ETDs
Twenty-six samples from hot springs and fumaroles in Yellowstone National Park (YNP) and 11 in Central America were analyzed for inorganic gases (CO2, SO2, H2S, HCl, Ar, N2, CO, H2, He, 02), methane, and trace volatile light hydrocarbons. Stable isotope analyses of carbon and nitrogen were used in conjunction with the gas geochemistry to determine potential sources of hydrocarbons.
δ13C-CH4 values ranged between -37.6 and-18.2‰ for YNP, from -31.9 to -30.2‰ for El Salvador, and from -38.8 to -23.9‰ for Honduras. δ13C-CO2 …
Lewis And Clark State Park Signs, Robert F. Diffendal Jr., Les Howard
Lewis And Clark State Park Signs, Robert F. Diffendal Jr., Les Howard
School of Natural Resources: Faculty Publications
Bob Diffendal wrote text and Les Howard created maps for new Lewis and Clark signs at Ponca State Park on the Missouri River.
The Corps of Discovery led by Meriwether Lewis and William Clark reached what is now southeastern Nebraska on July 10, 1804. It arrived at the point on the Missouri River adjacent to what is now Ponca State Park on August 22, 1804; and entered fully into South Dakota on September 8, 1804. Over this span of nearly two months members of the expedition saw and described many geologic features. The locations of some of the more prominent …
A Cost Effective Approach To Taxonomic Resolution For Bioassessment And Monitoring Programs In The State Of Georgia, Jodi Alene Williams
A Cost Effective Approach To Taxonomic Resolution For Bioassessment And Monitoring Programs In The State Of Georgia, Jodi Alene Williams
Theses and Dissertations
The Georgia Ecoregions Reference Sites Project has developed biological criteria for streams in Georgia according to the Rapid Bioassessment Protocols For Wadeable Streams and Rivers. Streams will ultimately be classified into categories of impairment so that management decisions can be made in accordance with the Clean Water Act. A cost-effective approach to accomplish mandates set forth by the Clean Water Act must be employed, as state budgets are limited. One means of examining costs is to assess taxonomic resolution. Taxonomic resolution not only assesses the sensitivity of biocriteria, it also allows one to make recommendations to state agencies regarding the …
Anthropogenic Lead Deposition And Four National Parks In Poland As Determined By Lead Isotope Ratios, Shannon Simcoe
Anthropogenic Lead Deposition And Four National Parks In Poland As Determined By Lead Isotope Ratios, Shannon Simcoe
OES Theses and Dissertations
Polluted soils are recognized by having high concentrations of heavy metals, including Pb. Partitioning of metals in geochemical fractions, by sequential chemical extractions, may indicate whether a metal has been recently deposited in the soil. While concentration levels alone cannot distinguish between natural and anthropogenic Pb, studies have demonstrated that anthropogenic pollution is accurately recorded by specific Pb isotope signatures, which differ from natural Pb isotopes. The objective of this project was to use 206Pb/207Pb and 206Pb/204Pb isotope ratios to differentiate between the anthropogenic Pb input and the naturally occurring Pb in four national …
Sediments, Facies Tracts, And Variations In Sedimentation Rates Of Holocene Platform Carbonate Sediments And Associated Deposits, Northern Belize -- Implications For "Representative" Sedimentation Rates, Wan Yang, Salvatore J. Mazzullo, Chellie S. Teal
Sediments, Facies Tracts, And Variations In Sedimentation Rates Of Holocene Platform Carbonate Sediments And Associated Deposits, Northern Belize -- Implications For "Representative" Sedimentation Rates, Wan Yang, Salvatore J. Mazzullo, Chellie S. Teal
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
In stratigraphic analysis and simulation, sedimentation rates are typically assumed to be constant for meter-scale sedimentation units of similar lithology. The rates of Holocene, shallow-marine carbonate and associated sediments within an 820 km2 area of Chetumal Bay in northern Belize were evaluated to test this assumption. Rates were determined from thickness data from 363 locations, durations derived from 14C age dates of mangrove peat on Pleistocene bedrock limestone and of overlying cerithid gravels, and reference to a sea-level curve for this area. The rate of entire Holocene sections (basal transgressive mangrove peat, shelly gravel, and overlying carbonate) varies …
Green River Ce-Qual-W2 Project: A Hydrodynamic And Water Quality Study Of The Green River King County, Washington, Tim Kraft, Robert Leslie Annear, Chris Berger, Scott A. Wells
Green River Ce-Qual-W2 Project: A Hydrodynamic And Water Quality Study Of The Green River King County, Washington, Tim Kraft, Robert Leslie Annear, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
This report describes the data processing and model calibration performed for a hydrodynamic and water quality model of the Green River, located in King County, Washington. Figure 1 shows the location of the river, and the limits of the section of river that was modeled.
The Green River flows from its headwaters in the Cascade Mountain foothills through the King County, Washington communities of Auburn, Kent, and Tukwila before discharging into the Duwamish River. Two sections of the river were modeled in this project. The Middle Green River begins in the Cascade Mountain foothills east of Tacoma, and continues downstream …
Platinum Group Element Mineralization In "Ballrooms" Of The J-M Reef Of The Stillwater Complex, Montana, Matthew P. Harper
Platinum Group Element Mineralization In "Ballrooms" Of The J-M Reef Of The Stillwater Complex, Montana, Matthew P. Harper
Theses and Dissertations
The J-M Reef of the Stillwater Complex, Montana (a large layered mafic intrusion), is one of the highest grade platinum group element (PGE) deposits known in the world, producing primarily palladium and platinum in a 3.4:1 ratio. "Ballrooms" of the Stillwater Complex are anomalously wide areas within or stratigraphically below the J-M Reef that host platinum group element mineralization. Ballrooms have two typical morphologies (type 1 and type 2); the first is an abrupt thickening of the mineralization that extends below the Reef Package and the second is a gentle widening of the Reef Package and associated reef mineralization to …
Slides: Intro To Groundwater Law In Colorado, David L. Harrison
Slides: Intro To Groundwater Law In Colorado, David L. Harrison
Groundwater in the West (Summer Conference, June 16-18)
Presenter: David L. Harrison.
17 slides.
Groundwater Management: Lessons From Colorado V. Kansas, David W. Robbins
Groundwater Management: Lessons From Colorado V. Kansas, David W. Robbins
Groundwater in the West (Summer Conference, June 16-18)
11 pages.
Slides: South Metro Denver Water Supply Study, Patricia Wells
Slides: South Metro Denver Water Supply Study, Patricia Wells
Groundwater in the West (Summer Conference, June 16-18)
Presenter: Patricia Wells, General Counsel, Denver Water.
23 slides.
The Future Of Groundwater In The West, James S. Lochhead
The Future Of Groundwater In The West, James S. Lochhead
Groundwater in the West (Summer Conference, June 16-18)
7 pages.
Slides: Ground Water Resources In Colorado, Matthew A. Sares
Slides: Ground Water Resources In Colorado, Matthew A. Sares
Groundwater in the West (Summer Conference, June 16-18)
Presenter: Matthew Sares, Chief, Environmental Geology Section, Colorado Geological Survey.
21 slides.
Intro To Ground Water Law In Colorado And Surface-Groundwater Conflicts In The South Platte, David Harrison, Veronica A. Sperling, Steven O. Sims
Intro To Ground Water Law In Colorado And Surface-Groundwater Conflicts In The South Platte, David Harrison, Veronica A. Sperling, Steven O. Sims
Groundwater in the West (Summer Conference, June 16-18)
25 pages.
Contains footnotes.
Slides: Coalbed Methane Water Quantity/Quality, Tom Darin
Slides: Coalbed Methane Water Quantity/Quality, Tom Darin
Groundwater in the West (Summer Conference, June 16-18)
Presenter: Tom Darin, Jackson Hole Conservation Alliance.
18 slides.
Advancing Binational Cooperation In Transboundary Aquifer Management On The U.S. Mexico Border [Paper And Presentation], Stephen P. Mumme
Advancing Binational Cooperation In Transboundary Aquifer Management On The U.S. Mexico Border [Paper And Presentation], Stephen P. Mumme
Groundwater in the West (Summer Conference, June 16-18)
Presenter: Steve Mumme, Colorado State University.
23 pages and 8 slides.
Contains footnotes.
Slides: The Spokane And The Yakima: A Tale Of Two Aquifers, Rachel Paschal Osborn
Slides: The Spokane And The Yakima: A Tale Of Two Aquifers, Rachel Paschal Osborn
Groundwater in the West (Summer Conference, June 16-18)
Presenter: Rachael Paschal Osborn, Private Practice and Gonzaga Law School.
89 slides.
Slides: Deep Trouble On The Plains: Conflicts Over Aquifer Mining, Management And Marketing, Ronald Kaiser
Slides: Deep Trouble On The Plains: Conflicts Over Aquifer Mining, Management And Marketing, Ronald Kaiser
Groundwater in the West (Summer Conference, June 16-18)
Presenter: Ron Kaiser, Texas A&M University.
47 slides.