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Full-Text Articles in Physical Sciences and Mathematics

The Effects Of Wet Meadow Fragmentation On Grassland Birds, Christopher J. Helzer Dec 1996

The Effects Of Wet Meadow Fragmentation On Grassland Birds, Christopher J. Helzer

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Histomorphological Responses Of Red Shiner (Cyprinella Lutrensis) To Atrazine, Terbufos, And Their Mixture, Ibrahim A. Messaad Dec 1996

Histomorphological Responses Of Red Shiner (Cyprinella Lutrensis) To Atrazine, Terbufos, And Their Mixture, Ibrahim A. Messaad

School of Natural Resources: Dissertations, Theses, and Student Research

Alterations of normal histomorphology of fish tissues, behavior, and thermal tolerance are recognized by environmental toxicologists and fish biologists as powerful tools indicating diverse biochemical and physiological changes. Toxicity of atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), terbufos (S-(((1,1-dimethyl-ethyl)thio)methyl)O,O-diethyl phosphorodithioate), and their mixture to red shiner (Cyprinella lutrensis) at 23$\sp\circ$C and 30$\sp\circ$C was investigated in 14-d bioassays after 14-d acclimation. During the bioassays, fish behavior, indications of toxicosis, and external anomalies were observed. After the bioassays, the critical thermal maximum (CTM) was determined. Fish also were preserved for examinations of gill, liver, and kidney tissues using scanning electron microscopy (SEM) and light microscopy (LM). SEM …


Propogation Of Juniperus For Conservation Plantings In The Great Plains, Scott Allen Lee Aug 1996

Propogation Of Juniperus For Conservation Plantings In The Great Plains, Scott Allen Lee

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


The Biology Of Alewife Alosa Pseudoharengus In Lake Ogallala, Nebraska, Eric A. Laux Aug 1996

The Biology Of Alewife Alosa Pseudoharengus In Lake Ogallala, Nebraska, Eric A. Laux

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Application Of Permutations To Lossless Compression Of Multispectral Thematic Mapper Images, Ziya Arnavut, Sunil Narumalani Jul 1996

Application Of Permutations To Lossless Compression Of Multispectral Thematic Mapper Images, Ziya Arnavut, Sunil Narumalani

Department of Earth and Atmospheric Sciences: Faculty Publications

The goal of data compression is to find shorter representa- tions for any given data. In a data storage application, this is done in order to save storage space on an auxiliary device or, in the case of a communication scenario, to increase channel throughput. Because re- motely sensed data require tremendous amounts of transmission and storage space, it is essential to find good algorithms that utilize the spa- tial and spectral characteristics of these data to compress them. A new technique is presented that uses a spectral and spatial correlation to create orderly data for the compression of multispectral …


Boundary Conditions For Convergent Radial Tracer Tests And Effect Of Well Bore Mixing Volume, Vitaly A. Zlotnik, John David Logan Jul 1996

Boundary Conditions For Convergent Radial Tracer Tests And Effect Of Well Bore Mixing Volume, Vitaly A. Zlotnik, John David Logan

Department of Earth and Atmospheric Sciences: Faculty Publications

Convergent radial flow tracer tests have a complex spatial nonaxial transport structure caused by the flow in the vicinity of the injection well and its finite mixing volume. The formulation of the boundary value problem, and especially the treatment of the boundary conditions at the injection well, is nontrivial. Hodgkinson and Lever [1983], Moench [1989, 1991], and Welty and Gelhar [1994] have developed different models and methods for the analysis of breakthrough curves in the extraction well. To extend interpretation techniques to breakthrough curves in the zone between injection and extraction wells, an analysis of conventional transport models is given, …


Chronic Effects Of Baseflow Levels Of Atrazine On Platte River Algae, Karen J. Nelson May 1996

Chronic Effects Of Baseflow Levels Of Atrazine On Platte River Algae, Karen J. Nelson

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Influence Of Prey Availability On Walleye (Stizostedion Vitreum), Mark T. Porath May 1996

Influence Of Prey Availability On Walleye (Stizostedion Vitreum), Mark T. Porath

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Growth And Yield Of Snap Beans (Phaseolus Vulgaris L.) As Affected By Shelterbelts And Planting Dates, Mohd Nazip Suratman May 1996

Growth And Yield Of Snap Beans (Phaseolus Vulgaris L.) As Affected By Shelterbelts And Planting Dates, Mohd Nazip Suratman

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Thermal Tolerances Of Platte River Fishes: Field And Laboratory Studies, Brett P. Fessell May 1996

Thermal Tolerances Of Platte River Fishes: Field And Laboratory Studies, Brett P. Fessell

School of Natural Resources: Dissertations, Theses, and Student Research

No abstract provided.


Theory Of Dipole Flow In Uniform Anisotropic Aquifers, Vitaly A. Zlotnik, Glenn Ledder Apr 1996

Theory Of Dipole Flow In Uniform Anisotropic Aquifers, Vitaly A. Zlotnik, Glenn Ledder

Department of Earth and Atmospheric Sciences: Faculty Publications

A theory of dipole flow is developed to model flow induced by a vertical circulation well consisting of injection and extraction chambers in a single borehole. Included in the theory are an analytical description of the kinematic flow structure around a vertical circulation well and the drawdown in the well chambers. Using Stokes’ stream function, simple criteria are derived to determine the region of intensive recirculation. This region extends (from the dipole center) approximately five distances between chamber centers in the radial direction and two distances between chamber centers in both vertical directions. The vertical scale does not depend on …


Paleolimnological Records Of Climatic Change In North America, Sherilyn C. Fritz Feb 1996

Paleolimnological Records Of Climatic Change In North America, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

Lacustrine fossil records provide long time series of data on limnological and climatic conditions; these data are useful for establishing natural patterns of climate variability and for generating testable hypotheses about atmospheric circulation and climate-ecosystem linkages. Shoreline features can indicate past lake-level fluctuations that may reflect changes in moisture balance, but often these records are discontinuous and are evidence of only extreme conditions. The organisms, geochemistry, and sedimentology of lake sediments may provide a more continuous sequence of direct and indirect lake-climate interactions in the past. The most clearly interpretable paleolimnnological records of climatic change are those that use several …


Century-Scale Paleoclimatic Reconstruction From Moon Lake, A Closed-Basin Lake In The Northern Great Plains, Kathleen R. Laird, Sherilyn C. Fritz, Eric C. Grimm, Pietra G. Mueller Feb 1996

Century-Scale Paleoclimatic Reconstruction From Moon Lake, A Closed-Basin Lake In The Northern Great Plains, Kathleen R. Laird, Sherilyn C. Fritz, Eric C. Grimm, Pietra G. Mueller

Department of Earth and Atmospheric Sciences: Faculty Publications

Estimates of past lake-water salinity from fossil diatom assemblages were used to infer past climatic conditions at Moon Lake, a climatically sensitive site in the northern Great Plains. A good correspondence between diatom-inferred salinity and historical records of mean annual precipitation minus evapotranspiration (P - ET) strongly suggests that the sedimentary record from Moon Lake can be used to reconstruct past climatic conditions. Century-scale analysis of the Holocene diatom record indicates four major hydrological periods: an early Holocene transition from an open freshwater system to a closed saline system by 7300 B.P., which corresponds with a transition from spruce forest …


Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith Feb 1996

Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith

Robert F. Diffendal, Jr., Publications

In 1990, as part of a national presidential initiative on water quality, researchers from the University of Nebraska–Lincoln (UNL) Institute of Agriculture and Natural Resources (IANR) received a multiyear grant from the U.S. Department of Agriculture, Cooperative State Research Service, to study management of irrigated corn and soybeans to minimize groundwater contamination. D. G. Watts, R. F. Spalding, and J.S. Schepers, of the IANR led a study at one of the Management Systems Evaluation Areas (MSEA). This area was made up of two sites, a primary site on a terrace of the Platte River near Shelton and a secondary site …


Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith Feb 1996

Geology Beneath The Primary Management Systems Evaluation Area (Msea) Site Southwest Of Shelton, Buffalo County, Nebraska, Robert F. Diffendal Jr., Frank A. Smith

Department of Earth and Atmospheric Sciences: Faculty Publications

In 1990, as part of a national presidential initiative on water quality, researchers from the University of Nebraska-Lincoln (UNL) Institute of Agriculture and Natural Resources (IANR) received a multi-year grant from the United States Department of Agriculture, Cooperative State Research Service, to study management of irrigated com and soybeans to minimize groundwater contamination. D.G. Watts, R.F. Spalding, and J.S. Schepers, of the IANR led a study at one of the Management Systems Evaluation Areas (MSEA). This area was made up of two sites, a primary site on a terrace of the Platte River near Shelton and a secondary site nearer …


Geologic History Of Ash Hollow State Historical Park, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian, J. R. Thomasson Feb 1996

Geologic History Of Ash Hollow State Historical Park, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian, J. R. Thomasson

Conservation and Survey Division

Contents:

Introduction
Acknowledgments
Cautions
General Stratigraphy
Oligocene Series-White River Group-Brule Formation-Whitney Member
Miocene Series-Ogallala Group-Ash Hollow Formation
Pliocene Series-Broadwater Formation
Quaternary deposits
Older colluvium and loess
Younger colluvium and alluvium
General Paleontology
Evidence of past life: fossils and subfossils
Collecting fossils
Vertebrate fossils
Fossils from the Whitney Member of the Brule Formation
Plants
Invertebrates
Vertebrates
Fossils from the Ash Hollow Formation
Plants
Invertebrates
Vertebrates
Fossils from the Broadwater Formation
Plants
Vertebrates
Quaternary fossils
Plants
Invertebrates
Vertebrates
Additional studies of Nebraska fossils
Geologic History
Prehistory and History
References
Appendices I-IV


Linking Planktonic Diatoms And Climate Change In The Large Lakes Of The Yellowstone Ecosystem Using Resource Theory, Susan S. Kilham, Edward C. Theriot, Sherilyn C. Fritz Feb 1996

Linking Planktonic Diatoms And Climate Change In The Large Lakes Of The Yellowstone Ecosystem Using Resource Theory, Susan S. Kilham, Edward C. Theriot, Sherilyn C. Fritz

Department of Earth and Atmospheric Sciences: Faculty Publications

Resource-based physiology of the eight important planktonic diatom species in the large lakes of the Yellowstone region can be used to explain their relative abundances and seasonal changes. The diatoms are ranked along resource ratio gradients according to their relative abilities to grow under limitation by Si, N, P, and light. Hypotheses based on resource physiology can be integrated with observations on seasonal changes in diatom assemblages to explain the present distributions of diatoms and to test the causal factors proposed to explain diatom distributions over the Holocene. Knowledge of the limnology of these lakes and process-oriented physiology provide the …


Multiport Well Design For Sampling Of Ground Water At Closely Spaced Vertical Intervals, Geoffrey N. Delin, Matthew K. Landon Jan 1996

Multiport Well Design For Sampling Of Ground Water At Closely Spaced Vertical Intervals, Geoffrey N. Delin, Matthew K. Landon

United States Geological Survey: Staff Publications

Detailed vertical sampling is useful in aquifers where vertical mixing is limited and steep vertical gradients in chemical concentrations are expected.


Effect Of Nitrate, Organic Carbon, And Temperature On Potential Denitrification Rates In Nitrate-Rich Riverbed Sediments, K. S. Pfenning, P. B. Mcmahon Jan 1996

Effect Of Nitrate, Organic Carbon, And Temperature On Potential Denitrification Rates In Nitrate-Rich Riverbed Sediments, K. S. Pfenning, P. B. Mcmahon

United States Geological Survey: Staff Publications

A study conducted in 1994 as part of the US Geological Survey's National Water-Quality Assessment Program, South Platte River Basin investigation, examined the effect of certain environmental factors on potential denitrification rates in nitrate-rich riverbed sediments. The acetylene block technique was used to measure nitrous oxide (N2O) production rates in laboratory incubations of riverbed sediments to evaluate the effect of varying nitrate concentrations, organic carbon concentrations and type, and water temperature on potential denitrification rates. Sediment incubations amended with nitrate, at concentrations ranging from 357 to 2142 μmol 1-1 (as measured in the field), produced no significant …


Climatic And Hydrologic Oscillations In The Owens Lake Basin And Adjacent Sierra Nevada, California, Larry Benson, James W. Burdett, Michaele Kashgarian, Steve Lund, Fred Phillips, Robert O. Rye Jan 1996

Climatic And Hydrologic Oscillations In The Owens Lake Basin And Adjacent Sierra Nevada, California, Larry Benson, James W. Burdett, Michaele Kashgarian, Steve Lund, Fred Phillips, Robert O. Rye

United States Geological Survey: Staff Publications

Oxygen isotope and total inorganic carbon values of cored sediments from the Owens Lake basin, California, indicate that Owens Lake overflowed most of the time between 52,500 and 12,500 carbon-14 (14C) years before present (B.P.). Owens Lake desicated during or after Heinrich event H1 and was hydrologically closed during Heinrich event H2. The magnetic susceptibility and organiz carbon content of cored sediments indicate that about 19 Sierra Nevada glaciations occurred between 52,500 and 23,500 14C years B.P.


Sea-Level Records At ~80 Ka From Tectonically Stable Platforms: Florida And Bermuda, K. R. Ludwig, D. R. Muhs, K. R. Simmons, R. B. Halley, E. A. Shinn Jan 1996

Sea-Level Records At ~80 Ka From Tectonically Stable Platforms: Florida And Bermuda, K. R. Ludwig, D. R. Muhs, K. R. Simmons, R. B. Halley, E. A. Shinn

United States Geological Survey: Staff Publications

Studies from tectonically active coasts on New Guinea and Barbados have suggested that sea level at ~80 ka was significantly lower than present, whereas data from the Atlantic and Pacific coasts of North America indicate an ~80 ka sea level close to that of the present. We determined ages of corals from a shallow submerged reef off the Florida Keys and an emergent marine deposit on Bermuda. Both localities are on tectonically stable platforms distant from plate boundaries. Uranium-series ages show that corals at both localities grew during the ~80 ka sea-level highstand, and geologic data show that sea level …


Pesticides In Streams Draining Agricultural And Urban Areas In Colorado, Robert Kimbrough, David Litke Jan 1996

Pesticides In Streams Draining Agricultural And Urban Areas In Colorado, Robert Kimbrough, David Litke

United States Geological Survey: Staff Publications

A study was conducted from April 1993 through April 1994 to describe and compare the occurrence and distribution of pesticides in streams in a small agricultural and a small urban area in Colorado. Twenty-five water samples collected at least monthly at the mouths of two tributary streams of the South Platte River were analyzed for 47 pesticides. The results indicate that both agricultural and urban areas are probable sources for pesticides in streams. In the agricultural area, 30 pesticides were detected, and in the urban area, 22 pesticides were detected in one or more samples. Most often, the more frequently …


Acetochlor In The Hydrologic System In The Midwestern United States, 1994, Dana Kolpin, Brenda Nations, Donald Goolsby, E. Michael Thurman Jan 1996

Acetochlor In The Hydrologic System In The Midwestern United States, 1994, Dana Kolpin, Brenda Nations, Donald Goolsby, E. Michael Thurman

United States Geological Survey: Staff Publications

The herbicide acetochlor [2-chloro-N-(ethoxymethyl)- N-(2-ethyl-6-methylphenyl)acetamide] was given conditional registration in the United States by the U.S. Environmental Protection Agency in March 1994. This registration provided a rare opportunity to investigate the occurrence of a pesticide during its first season of extensive use in the midwestern United States. Water samples collected and analyzed by the U.S. Geological Survey during 1994 documented the distribution of acetochlor in the hydrologic system; it was detected in 29% of the rain samples from four sites in Iowa, 17% of the stream samples from 51 sites across nine states, and 0% of the groundwater samples from …


Origin Of Bermuda's Clay-Rich Quaternary Paleosols And Their Paleoclimatic Significance, Stanley R. Herwitz, Daniel R. Muhs, Joseph M. Prospero, Shannon Mahan, Bruce Vaughn Jan 1996

Origin Of Bermuda's Clay-Rich Quaternary Paleosols And Their Paleoclimatic Significance, Stanley R. Herwitz, Daniel R. Muhs, Joseph M. Prospero, Shannon Mahan, Bruce Vaughn

United States Geological Survey: Staff Publications

Saharan dust deposition on Bermuda during successive Quaternary glacial periods is consistent with patterns of general circulation models, which indicate that during glacial maxima the northeast summer trade winds were stronger than at present and reached latitudes higher than 30°N despite lower-than-present sea surface temperatures in the North Atlantic.


Occurrence Of Selected Pesticides And Their Metabolites In Near-Surface Aquifers Of The Midwestern United States, Dana Kolpin, E. Michael Thurman, Donald Goolsby Jan 1996

Occurrence Of Selected Pesticides And Their Metabolites In Near-Surface Aquifers Of The Midwestern United States, Dana Kolpin, E. Michael Thurman, Donald Goolsby

United States Geological Survey: Staff Publications

The occurrence and distribution of selected pesticides and their metabolites were investigated through the collection of 837 water-quality samples from 303 wells across the Midwest. Results of this study showed that five of the six most frequently detected compounds were pesticide metabolites. Thus, it was common for a metabolite to be found more frequently in groundwater than its parent compound. The metabolite alachlor ethanesulfonic acid (alachlor- ESA; 2-[(2,6-diethylphenyl)(methoxymethyl)amino]-2- oxoethanesulfonic acid) was detected almost 10 times as frequently and at much higher concentrations than its parent compound alachlor (2-chloro-2',6'- diethyl-N-(methoxymethyl)acetamide). The median detectable atrazine (2-chloro-4-ethylamino-6- isopropylamino-s-triazine) concentration was almost half that …


Burt County Test Hole Logs, Raymond R. Burchett, Frank A. Smith Jan 1996

Burt County Test Hole Logs, Raymond R. Burchett, Frank A. Smith

Conservation and Survey Division

No abstract provided.


Geology Of The Liquid Propane Gas Storage Facility Near Greenwood, Nebraska, R. R. Burchett Jan 1996

Geology Of The Liquid Propane Gas Storage Facility Near Greenwood, Nebraska, R. R. Burchett

Conservation and Survey Division

No abstract provided.


Rural Domestic Well-Water Quality In The Sand Hills, D C. Gosselin Jan 1996

Rural Domestic Well-Water Quality In The Sand Hills, D C. Gosselin

Conservation and Survey Division

No abstract provided.


Regional Hydrogeologic Summaries From Domestic Water-Well Quality In Nebraska -- Hat Creek-White River Drainage Basin, D. C. Gosselin, J. Headrick, X- H. Chen, S. E. Summerside Jan 1996

Regional Hydrogeologic Summaries From Domestic Water-Well Quality In Nebraska -- Hat Creek-White River Drainage Basin, D. C. Gosselin, J. Headrick, X- H. Chen, S. E. Summerside

Conservation and Survey Division

No abstract provided.


Regional Analysis Of Rural Domestic Well-Water Quality -- South Central Plains, D. C. Gosselin, J. Headrick, X- H. Chen, S. E. Summerside Jan 1996

Regional Analysis Of Rural Domestic Well-Water Quality -- South Central Plains, D. C. Gosselin, J. Headrick, X- H. Chen, S. E. Summerside

Conservation and Survey Division

No abstract provided.