Physiological levels of testosterone kill salmonid leukocytes in vitro
C.H. Slater, C.B. Schreck
1997, General and Comparative Endocrinology (106) 113-119
Adult spring chinook salmon (Oncorhynchus tshawytscha) elaborate high plasma concentrations of testosterone during sexual maturation, and these levels of testosterone have been shown to reduce the salmonid immune response in vitro. Our search for the mechanism of testosterone's immunosuppressive action has led to the characterization of an androgen receptor in...
Site amplifications for generic rock sites
D.M. Boore, W. B. Joyner
1997, Bulletin of the Seismological Society of America (87) 327-341
Seismic shear-wave velocity as a function of depth for generic rock sites has been estimated from borehole data and studies of crustal velocities, and these velocities have been used to compute frequency-dependent amplifications for zero attenuation for use in simulations of strong ground motion. We define a generic rock site...
Potential effects of climate change on aquatic ecosystems of the Great Plains of North America
A.P. Covich, S.C. Fritz, P.J. Lamb, R.D. Marzolf, W.J. Matthews, K.A. Poiani, E.E. Prepas, M.B. Richman, T. C. Winter
1997, Hydrological Processes (11) 993-1021
The Great Plains landscape is less topographically complex than most other regions within North America, but diverse aquatic ecosystems, such as playas, pothole lakes, ox-bow lakes, springs, groundwater aquifers, intermittent and ephemeral streams, as well as large rivers and wetlands, are highly dynamic and responsive to extreme climatic fluctuations. We...
The use of multifrequency and polarimetric SIR-C/X-SAR data in geologic studies of Bir Safsaf, Egypt
G. G. Schaber, J.F. McCauley, C. S. Breed
1997, Remote Sensing of Environment (59) 337-363
Bir Safsaf, within the hyperarid 'core' of the Sahara in the Western Desert of Egypt, was recognized following the SIR-A and SIR-B missions in the 1980s as one of the key localities in northeast Africa, where penetration of dry sand by radar signals delineates previously unknown, sand-buried paleodrainage valleys ('radar-rivers')...
Deep-coal potential in the Appalachian Coal Basin, USA: The Kentucky model
D. C. Haney, D.R. Chesnut Jr.
1997, Prace - Panstwowego Instytutu Geologicznego 336-337
The Eastern Kentucky Coal Field is located in the Appalachian Basin of the United States and occupies an area of approximately 15,000 square kilometers. The coal beds range from a few centimeters to several meters in thickness and consist of high-grade bituminous coal. Currently the amount of coal mined by...
Application of the LI-COR CO2 analyzer to volcanic plumes: a case study, volcán Popocatépetl, Mexico, June 7 and 10, 1995
T.M. Gerlach, H. Delgado, K.A. McGee, M.P. Doukas, J.J. Venegas, L. Cardenas
1997, Journal of Geophysical Research B: Solid Earth (102) 8005-8019
Volcanic CO2 emission rate data are sparse despite their potential importance for constraining the role of magma degassing in the biogeochemical cycle of carbon and for assessing volcanic hazards. We used a LI-COR CO2 analyzer to determine volcanic CO2 emission rates by airborne measurements in volcanic plumes at Popocatépetl volcano...
Morphology and distribution of seamounts surrounding Easter Island
Y. Rappaport, D. F. Naar, C.C. Barton, Z.-J. Liu, R.N. Hey
1997, Journal of Geophysical Research B: Solid Earth (102) 24713-24728
We investigate the morphology and distribution of a seamount population on a section of seafloor influenced by both superfast seafloor spreading and hotspot volcanism. The population under investigation is part of a broad chain of seamounts extending eastward from the East Pacific Rise, near Easter Island. In order to define...
Demersal fish assemblages of the northeastern Chukchi Sea, Alaska
W.E. Barber, R. L. Smith, M. Vallarino, R.M. Meyer
1997, Fishery Bulletin (95) 195-209
We documented the distribution and abundance of demersal fishes in the northeastern Chukchi Sea, Alaska, in 1990 and 1991, and described 1990 demersal fish assemblages and their relationship to general oceanographic features in the area. We collected samples using an otter trawl at 48 stations in 1990 and 16 in...
Testing alternative conceptual models of seawater intrusion in a coastal aquifer using computer simulation, southern California, USA
Tracy Nishikawa
1997, Hydrogeology Journal (5) 60-74
Two alternative conceptual models of the physical processes controlling seawater intrusion in a coastal basin in California, USA, were tested to identify a likely principal pathway for seawater intrusion. The conceptual models were tested by using a two-dimensional, finite-element groundwater flow and transport model. This pathway was identified by the...
Predicting the probability of elevated nitrate concentrations in the Puget Sound Basin: Implications for aquifer susceptibility and vulnerability
A. J. Tesoriero, F.D. Voss
1997, Ground Water (35) 1029-1039
The occurrence and distribution of elevated nitrate concentrations (≥ 3 mg/l) in ground water in the Puget Sound Basin, Washington, were determined by examining existing data from more than 3000 wells. Models that estimate the probability that a well has an elevated nitrate concentration were constructed by relating the occurrence...
Measurement of flow under ice covers in North America
J.F. Walker, D. Wang
1997, Journal of Hydraulic Engineering (123) 1037-1040
A substantial proportion of natural streams in the United States and Canada are affected by ice cover during the winter. To substantiate the currently used procedures for measuring streamflow during the winter, the U.S. Geological Survey (USGS) and Water Survey of Canada (WSC) began independent, coordinated programs for research and...
Stable isotope evidence for an atmospheric origin of desert nitrate deposits in northern Chile and southern California, U.S.A.
J.K. Böhlke, G. E. Ericksen, K. Revesz
1997, Chemical Geology (136) 135-152
Natural surficial accumulations of nitrate-rich salts in the Atacama Desert, northern Chile, and in the Death Valley region of the Mojave Desert, southern California, are well known, but despite many geologic and geochemical studies, the origins of the nitrates have remained controversial. N...
Distribution and stability of eelgrass beds at Izembek Lagoon, Alaska
David H. Ward, Carl J. Markon, David C. Douglas
1997, Aquatic Botany (58) 229-240
Spatial change in eelgrass meadows, Zostera marina L., was assessed between 1978 and 1987 and between 1987 and 1995 at Izembek Lagoon, Alaska. Change in total extent was evaluated through a map to map comparison of data interpreted from a 1978 Landsat multi-spectral scanner image and 1987 black and white...
Bedrock geology of snyderville basin: Structural geology techniques applied to understanding the hydrogeology of a rapidly developing region, Summit County, Utah
K.E. Keighley, W.A. Yonkee, F.X. Ashland, J.P. Evans
1997, Brigham Young University Geology Studies (42) 325-343
The availability of ground water is a problem for many communities throughout the west. As these communities continue to experience growth, the initial allocation of ground water supplies proves inadequate and may force restrictions on existing, and future, development plans. Much of this new growth relies on ground water supplies...
Strengths of serpentinite gouges at elevated temperatures
Diane E. Moore, D.A. Lockner, S. Ma, R. Summers, J.D. Byerlee
1997, Journal of Geophysical Research B: Solid Earth (102) 14787-14801
Serpentinite has been proposed as a cause of both low strength and aseismic creep of fault zones. To test these hypotheses, we have measured the strength of chrysotile-, lizardite-, and antigorite-rich serpentinite gouges under hydrothermal conditions, with emphasis on chrysotile, which has thus far received little attention. At 25°C, the...
Some thoughts on problems associated with various sampling media used for environmental monitoring
A. J. Horowitz
1997, Conference Paper, Analyst
Modern analytical instrumentation is capable of measuring a variety of trace elements at concentrations down into the single or double digit parts-per-trillion (ng l-1) range. This holds for the three most common sample media currently used in environmental monitoring programs: filtered water, whole-water and separated suspended sediment. Unfortunately, current analytical...
Geochronologic and paleomagnetic evidence defining the relationship between the Miocene Hiko and Racer Canyon tuffs, eccentric outflow lobes from the Caliente caldera complex, southeastern Great Basin, USA
S. Gromme, A.M. Deino, M. G. Best, M.R. Hudson
1997, Bulletin of Volcanology (59) 21-35
Outflow sheets of the Hiko tuff and the Racer Canyon tuff, which together extend over approximately 16 000 km2 around the Caliente caldera complex in southeastern Nevada, have long been considered to be products of simultaneous or near-simultaneous eruptions from inset calderas in the west and east ends,...
A study of the temporal variability of atrazine in private well water. Part I: Study design, implementation, and database development
M. Lorber, Kevin Johnson, B. Kross, P. Pinsky, L. Burmeister, M. Thurman, A. Wilkins, G. Hallberg
1997, Environmental Monitoring and Assessment (47) 175-195
In 1988, the Iowa Department of Natural Resources, along with the University of Iowa conducted the Statewide Rural Well Water Survey, commonly known as SWRL. A total of 686 private rural drinking water wells was selected by use of a probability sample and tested for pesticides and nitrates. Sixty-eight of...
Predicting travel time and dispersion in rivers and streams
H.E. Jobson
1997, Journal of Hydraulic Engineering (123) 971-978
The possibility of a contaminant being accidentally or intentionally spilled in a river is a constant concern to those using the water. Methods are developed to estimate: (1) the velocity of a contaminant in a river; (2) the rate of attenuation of the peak concentration of a conservative contaminant; and...
Evaluation of process errors in bed load sampling using a Dune Model
Basil Gomez, Brent M. Troutman
1997, Water Resources Research (33) 2387-2398
Reliable estimates of the streamwide bed load discharge obtained using sampling devices are dependent upon good at-a-point knowledge across the full width of the channel. Using field data and information derived from a model that describes the geometric features of a dune train in terms of a spatial process observed...
Concentrations of chlorinated organic compounds in biota and bed sediment in streams of the San Joaquin Valley, California
L. R. Brown
1997, Archives of Environmental Contamination and Toxicology (33) 357-368
Samples of resident biota and bed sediments were collected in 1992 from 18 sites on or near the floor of the San Joaquin Valley, California, for analysis of 33 organochlorine compounds. The sites were divided into five groups on the basis of physiographic region and land use. Ten compounds were...
Simulation of ground-water level fluctuations using recharge estimated by field infiltrometer measurements
E.D. Swain
1997, Journal of Hydraulic Engineering (123) 904-911
An infiltrometer was used at multiple locations at a site in Lee County, Fl. to define the spatial variability in infiltration parameters. Water-level data from a well at this site were collected hourly and used to determine the temporal variability in recharge. These results were used to define recharge in...
Logistic model of nitrate in streams of the upper-midwestern United States
D. K. Mueller, B. C. Ruddy, W.A. Battaglin
1997, Journal of Environmental Quality (26) 1223-1230
Nitrate in surface water can have adverse effects on aquatic life and, in drinking-water supplies, can be a risk to human health. As part of a regional study, nitrates as N (NO3-N) was analyzed in water samples collected from streams throughout 10 Midwestern states during synoptic surveys in 1989, 1990,...
How wide is a road? The association of roads and mass-wasting in a forested montane environment
M. C. Larsen, J.E. Parks
1997, Earth Surface Processes and Landforms (22) 835-848
A spatial data base of 1609 landslides was analysed using a geographic information system to determine landslide frequency in relation to highways. A 126 km long transportation network in a 201km2 area of humid-tropical, mountainous, forested terrain in Puerto Rico was used in conjunction with a series of 20 buffer...
An algorithm for computing moments-based flood quantile estimates when historical flood information is available
T.A. Cohn, W.L. Lane, W.G. Baier
1997, Water Resources Research (33) 2089-2096
This paper presents the expected moments algorithm (EMA), a simple and efficient method for incorporating historical and paleoflood information into flood frequency studies. EMA can utilize three types of at-site flood information: systematic stream gage record; information about the magnitude of historical floods; and knowledge of the number of years...
