Identification of a basaltic component on the Martian surface from Thermal Emission Spectrometer data
P. R. Christensen, J. L. Bandfield, M. D. Smith, V.E. Hamilton, Roger N. Clark
2000, Journal of Geophysical Research: Planets (105) 9609-9621
The Mars Global Surveyor Thermal Emission Spectrometer (TES) instrument collected 4.8×106 spectra of Mars during the initial aerobraking and science‐phasing periods of the mission (September 14, 1997, through April 29, 1998). Two previously developed atmosphere‐removal models were applied to data from Cimmeria Terra (25°S, 213°W). The surface spectra derived for these...
Effects of temperature anomalies on the Palmer Drought Severity Index in the central United States
Qi Hu, Gary D. Willson
2000, International Journal of Climatology (20) 1899-1911
The purpose of this study is to improve our understanding of temperature and precipitation effects on the Palmer Drought Severity Index (PDSI). Both theoretical and observational analyses were applied to separate and compare temperature and precipitation effects on PDSI. The results showed that because of the dependence of PDSI on...
Geology of the Uranius Group Volcanic Constructs: Uranius Patera, Ceraunius Tholus, and Uranius Tholus
J. B. Plescia
2000, Icarus (143) 376-396
Uranius Patera, Ceraunius Tholus, and Uranius Tholus (three small constructs in the northeast Tharsis region) date to the Late Hesperian Epoch and define the earliest phases of constructional volcanism in the Tharsis province. All three volcanoes are interpreted as shields, built by effusive eruptions of low-viscosity lavas, presumably basalt. Ceraunius...
Energy budgets of mining-induced earthquakes and their interactions with nearby stopes
Art McGarr
2000, Conference Paper, International Journal of Rock Mechanics and Mining Sciences
In the early 1960's, N.G.W. Cook, using an underground network of geophones, demonstrated that most Witwatersrand tremors are closely associated with deep level gold mining operations. He also showed that the energy released by the closure of the tabular stopes at depths of the order of 2 km was more...
Comparison of an enzyme-linked immunosorbent assay (ELISA) to gas chromatography (GC) - measurement of polychlorinated biphenyls (PCBs) in selected US fish extracts
J.L. Zajicek, D. E. Tillitt, T.R. Schwartz, C. J. Schmitt, R.O. Harrison
2000, Chemosphere (40) 539-548
The analysis of PCBs in fish tissues by immunoassay methods was evaluated using fish collected from a US monitoring program, the National Contaminant Biomonitoring Program of the US Department of Interior, Fish and Wildlife Service. Selected composite whole fish samples, which represented widely varying concentrations and sources of PCBs, were...
Use of radioimmunoassay as a screen for antibiotics in confined animal feeding operations and confirmation by liquid chromatography/mass spectrometry
M. T. Meyer, J.E. Bumgarner, J.L. Varns, J.V. Daughtridge, E.M. Thurman, K.A. Hostetler
2000, Science of Total Environment (248) 181-187
Approximately one-half of the 50 000000 lb of antibiotics produced in the USA are used in agriculture. Because of the intensive use of antibiotics in the management of confined livestock operations, the potential exists for the transport of these compounds and their metabolites into our nation's water resources. A commercially...
The North American Reporting Center for Amphibian Malformations
Douglas H. Johnson, S.C. Fowle, J.A. Jundt
2000, Journal of the Iowa Academy of Science (107) 123-127
No abstract available....
Anthropogenic platinum and palladium in the sediments of Boston Harbor
C.B. Tuit, G.E. Ravizza, Michael H. Bothner
2000, Environmental Science & Technology (34) 927-932
Anthropogenic activity has increased recent sediment concentrations of Pt and Pd in Boston Harbor by approximately 5 times background concentrations. Surface sediments and downcore profiles were investigated to evaluate Pt and Pd accumulation and behavior in urban coastal sediments. There is no clear correlation between temporal changes in Pt and...
The use of waveform shapes to automatically determine earthquake focal depth
S.A. Sipkin
2000, Bulletin of the Seismological Society of America (90) 248-254
Earthquake focal depth is an important parameter for rapidly determining probable damage caused by a large earthquake. In addition, it is significant both for discriminating between natural events and explosions and for discriminating between tsunamigenic and nontsunamigenic earthquakes. For the purpose of notifying emergency management and disaster relief organizations as...
Plants as indicators of focused ground water discharge to a northern Minnesota lake
D.O. Rosenberry, Robert G. Striegl, D.C. Hudson
2000, Ground Water (38) 296-303
Determining the discharge of ground water to Shingobee Lake (66 ha), north-central Minnesota, is complicated by the presence of numerous springs situated adjacent to the lake and in the shallow portion of the lakebed. Springs first had to be located before these areas of more rapid discharge could be quantified....
Hypoxia tolerance of introduced Nile perch: Implications for survival of indigenous fishes in the Lake Victoria basin
Pamela J. Schofield, Lauren J. Chapman
2000, African Zoology (35) 35-42
The introduction of predatory Nile perch (Lates niloticus) into the Lake Victoria basin coincided with a dramatic decline in fish diversity. However, remnant populations of indigenous fishes persist in lagoons and satellite lakes separated from the main lakes by extensive areas of swamp, while other indigenous species find refuge in...
Fate of oxygen losses from Typha domingensis (Typhaceae) and Cladium jamaicense (Cyperaceae) and consequences for root metabolism
A. Chabbi, K.L. McKee, I.A. Mendelssohn
2000, American Journal of Botany (87) 1081-1090
The objective of this work was to determine whether radial oxygen loss (ROL) from roots of Typha domingensis and Cladium jamaicense creates an internal oxygen deficiency or, conversely, indicates adequate internal aeration and leakage of excess oxygen to the rhizosphere. Methylene blue in agar was used to quantify oxygen leakage....
Predictable interregional movements by female northern pintails during winter
R. R. Cox Jr., A. D. Afton
2000, Waterbirds (23) 258-269
Factors influencing initiation of regional and interregional movements by nonbreeding ducks are poorly understood, especially during winter. During winters 1990-1991 through 1992-1993, we radiotagged 347 female Northern Pintails (Anas acuta) in southwestern Louisiana and monitored their movements to three regions: (1) the Gulf Coast Region of Louisiana and Texas (outside...
Growth and invasive potential of Sapium sebiferum (Euphorbiaceae) within the coastal prairie region: the effects of soil and moisture regime
T.C. Barrilleaux, J.B. Grace
2000, American Journal of Botany (87) 1099-1106
The introduced tree Sapium sebiferum (Euphorbiaceae) is considered a serious threat to the preservation of the coastal prairie region of Louisiana and Texas, although it is currently uncommon in the western part of the region. The objective of this study was to evaluate the potential effects of location, soils, and...
Terrain analysis of the racetrack basin and the sliding rocks of Death Valley
P. Messina, P. Stoffer
2000, Geomorphology (35) 253-265
The Racetrack Playa's unusual surface features known as sliding rocks have been the subject of an ongoing debate and several mapping projects for half a century, although the causative mechanism remains unresolved. Clasts ranging in volume from large pebbles to medium boulders have, unwitnessed, maneuvered around the nearly flat dry...
A comparison of delta change and downscaled GCM scenarios for three mountainous basins in the United States
L.E. Hay, R.L. Wilby, G.H. Leavesley
2000, Journal of the American Water Resources Association (36) 387-397
Simulated daily precipitation, temperature, and runoff time series were compared in three mountainous basins in the United States: (1) the Animas River basin in Colorado, (2) the East Fork of the Carson River basin in Nevada and California, and (3) the Cle Elum River basin in Washington State. Two methods...
Broadcast application of a placebo rodenticide bait in a native Hawaiian forest
P.A. Dunlevy, E. Wm. Campbell III, G.D. Lindsey
2000, International Biodeterioration and Biodegradation (45) 199-208
This study consisted of three replicates of controlled field trials using a pelletized placebo (Ramik?? Green formulated without diphacinone) bait treated with a biological marker and broadcast at three application rates - 11.25, 22.5 and 33.75 kg/ha. We determined that Polynesian (Rattus exulans) and roof rats (Rattus rattus) consumed this...
Comparative habitat ecology of Texas and masked bobwhites
F.S. Guthery, N.M. King, K.R. Nolte, W.P. Kuvlesky Jr., S. DeStefano, S.A. Gall, N.J. Silvy
2000, Journal of Wildlife Management (64) 407-420
The habitat ecology of masked bobwhites (Colinus virginianus ridgwayi) is poorly understood, which hampers recovery efforts for this endangered bird. During 1994-96, we analyzed the habitat ecology of masked bobwhites in Sonora, Mexico, and Arizona, and compared these findings with the habitat ecology of Texas bobwhites (C. v. texanus) in...
Seismicity of California's north coast
W. H. Bakun
2000, Bulletin of the Seismological Society of America (90) 797-812
At least three moment magnitude (M) 7 earthquakes occurred along California's north coast in the second half of the nineteenth century. The M 7.3 earthquake on 23 November 1873 occurred near the California-Oregon coast and likely was located on the Cascadia subduction zone or within the North American plate. The...
New records of sylvatic plague in Kansas
J.F. Cully Jr., L.G. Carter, K.L. Gage
2000, Journal of Wildlife Diseases (36) 389-392
Sylvatic plague, or plague of wild rodents is caused by Yersinia pestis and entered California (USA) from Asia about 1899. Extensive sampling during the 1930's and 1940's documented the spread of plague to approximately its current distribution in North America. Records from the Centers for Disease Control and Prevention document plague in...
Changes in herbicide concentrations in Midwestern streams in relation to changes in use, 1989-1998
E.A. Scribner, W.A. Battaglin, D. A. Goolsby, E.M. Thurman
2000, Science of Total Environment (248) 255-263
Water samples were collected from Midwestern streams in 1994–1995 and 1998 as part of a study to help determine if changes in herbicide use resulted in changes in herbicide concentrations since a previous reconnaissance study in 1989–1990. Sites were sampled during the first significant runoff period after the application of...
Effect of a constructed wetland on disinfection byproducts: Removal processes and production of precursors
C.E. Rostad, Barbara S. Martin, L. B. Barber, J.A. Leenheer, S.R. Daniel
2000, Environmental Science & Technology (34) 2703-2710
The fate of halogenated disinfection byproducts (DBPs) in treatment wetlands and the changes in the DBP formation potential as wastewater treatment plant (WWTP)-derived water moves through the wetlands were investigated. Wetland inlet and outlet samples were analyzed for total organic halide (TOX), trihalomethanes (TH M), haloacetic acids (HAA), dissolved organic...
Distribution and habitat use by manatees (Trichechus manatus manatus) in Belize and Chetumal Bay, Mexico
B. Morales-Vela, D. Olivera-Gomez, J.E. Reynolds III, G. B. Rathbun
2000, Biological Conservation (95) 67-75
The nearshore coastal areas of Belize and of Chetumal Bay, Mexico, support one of the largest populations of manatees (Trichechus manatus manatus) in the Caribbean. In order to further document the distribution, relative abundance, habitat associations, and status of this population, we conducted three aerial surveys. The flights were done...
Numerical model of frazil ice and suspended sediment concentrations and formation of sediment laden ice in the Kara Sea
C. R. Sherwood
2000, Journal of Geophysical Research C: Oceans (105) 14061-14080
A one-dimensional (vertical) numerical model of currents, mixing, frazil ice concentration, and suspended sediment concentration has been developed and applied in the shallow southeastern Kara Sea. The objective of the calculations is to determine whether conditions suitable for turbid ice formation can occur during times of rapid cooling and wind-...
Modelling carbon responses of tundra ecosystems to historical and projected climate: A comparison of a plot- and a global-scale ecosystem model to identify process-based uncertainties
Joy S. Clein, B.L. Kwiatkowski, A. D. McGuire, J.E. Hobbie, E. B. Rastetter, J. M. Melillo, D. W. Kicklighter
2000, Global Change Biology (6) 127-140
We are developing a process-based modelling approach to investigate how carbon (C) storage of tundra across the entire Arctic will respond to projected climate change. To implement the approach, the processes that are least understood, and thus have the most uncertainty, need to be identified and studied. In this paper,...
