Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Results

184617 results.

Alternate formats: RIS file of the first 3000 search results  |  Download all results as CSV | TSV | Excel  |  RSS feed based on this search  |  JSON version of this page of results

Page 4600, results 114976 - 115000

Show results on a map

Publication Extents

Not all publications have extents, not all extents are completely accurate
MARKOV: A methodology for the solution of infinite time horizon MARKOV decision processes
B. Kenneth Williams
1988, Applied Stochastic Models and Data Analysis (4) 253-271
Algorithms are described for determining optimal policies for finite state, finite action, infinite discrete time horizon Markov decision processes. Both value-improvement and policy-improvement techniques are used in the algorithms. Computing procedures are also described. The algorithms are appropriate for processes that are either finite or infinite, deterministic or stochastic, discounted...
Organochlorine pesticides, polychlorinated biphenyls, and mercury in osprey eggs – 1970-79 – And their relationships to shell thinning and productivity
Stanley N. Wiemeyer, Christine M. Bunck, Alexander J. Krynitsky
1988, Archives of Environmental Contamination and Toxicology (17) 767-787
Osprey (Pandion haliaetus) eggs were collected in 14 states in 1970–79 and analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), and mercury. Moderate shell thinning occurred in eggs from several areas. DDE was detected in all eggs, PCBs in 99%, DDD in 96%, dieldrin in 52%, and other compounds less frequently....
Host selection by the shiny cowbird
J. W. Wiley
1988, Condor (90) 289-303
Factors important in Shiny Cowbird (Molothrus bonariensis) host selection were examined within the mangrove community in Puerto Rico. Cowbirds did not parasitize birds in proportion to their abundance. The cowbird breeding season coincided with those of its major hosts, which were 'high-quality' foster species (i.e., species that fledge .gtoreq. 55%...
Birds and environmental contaminants in San Francisco and Chesapeake Bays
H. M. Ohlendorf, W. James Fleming
1988, Marine Pollution Bulletin (19) 487-495
The direct and indirect effects of human activities, including environmental contamination, upon bird populations in San Francisco Bay and Chesapeake Bay are imperfectly understood, and few data are available. that allow a comparison of the contamination levels in birds from these two areas. Certain trace elements and organochlorine compounds have...
Postfledging survival of European starlings exposed as nestlings to an organophosphorus insecticide
K. L. Stromborg, C.E. Grue, J.D. Nichols, Gary R. Hepp, J.E. Hines, H. C. Bourne
1988, Ecology (69) 590-601
To test the hypothesis that exposure to organophosphorus (OP) insecticides reduces postfledging survival of altricial birds, 16—d—old European Starlings (Sturnus vulgaris) were weighed and orally dosed with corn oil containing 6.0 mg of dicrotophos per kilogram of body mass or an equivalent exposure of pure corn oil (controls). Two days...
Reproduction in black-crowned night-herons fed selenium
G. J. Smith, G. H. Heinz, D. J. Hoffman, J. W. Spann, A. J. Krynitsky
1988, Lake and Reservoir Management (4) 175-180
Agricultural and industrial practices can produce wastewater that contains high concentrations of selenium, a naturally-occurring trace element. Selenium entering aquatic systems through wastewater inflow can accumulate in aquatic food chains to levels that may be toxic to fish and wildlife species. Mallard reproduction is known to be adversely affected by...
Food habits and distribution of wintering canvasbacks, Aythya valisineria, on Chesapeake Bay
Matthew C. Perry, F.M. Uhler
1988, Estuaries (11) 57-67
Baltic clams (Macoma balthica) were the predominant food items of 323 canvasbacks (Aythya valisineria) collected throughout Chesapeake Bay during 1970–1979. Natural vegetation constituted 4% of the food volume. Widgeongrass (Ruppia maritima) and redhead grass (Potamogeton perfoliatus) constituted the greatest percent volume and frequency of occurrence among the plant species, whereas...
Bioaccumulation of selenium by snakes and frogs in the San Joaquin Valley, California
H. M. Ohlendorf, R. L. Hothem, Thomas W. Aldrich
1988, Copeia (1988) 704-710
Livers of gopher snakes (Pituophis melanoleucus) from Kesterson Reservoir (Merced County, California) contained significantly higher mean selenium concentrations (11.1 .mu.g/g, dry weight) than those from two nearby reference sites (2.05 and 2.14 .mu.g/g). Livers of bullfrogs (Rana catesbeiana) collected from the San Luis Drain at Kersterson Reservoir also contained significantly...
Organochlorine and mercury residues in Swainson's and ferruginous hawk eggs collected in North and South Dakota, 1974-79
Rey C. Stendell, David S. Gilmer, Nancy A. Coon, Douglas M. Swineford
1988, Environmental Monitoring and Assessment (10) 37-41
Residues of organochlorine pesticides, polychlorinated biphenyls (PCBs), and mercury were measured in eggs of Swainson's hawks (Buteo swainsoni) and ferruginous hawks (B. regalis) collected in North and South Dakota during 1974–79. DDE was the most common compound detected in the eggs, but residues were below levels...
Effects of dietary fluoride on reproduction in eastern screech-owls
O. H. Pattee, Stanley N. Wiemeyer, D. M. Swineford
1988, Archives of Environmental Contamination and Toxicology (17) 213-218
Sixty-six eastern screech-owls (Otus asio) were paired and randomly assigned to dietary treatment groups of 0, 40, or 200 ppm (mg/kg) fluoride (as sodium fluoride) in November 1981. Hatching success was adversely affected at the 200 ppm (mg/kg) level, suggesting potential detrimental impacts to wild populations exposed to fluoride pollution....
Whooping crane recovery: Progress through research
J. W. Carpenter, D.G. Smith
1988, Zooview (22) 5
Cooperative efforts of the Canadian Wildlife Service (CWS), U.S. Fish and Wildlife Service (FWS), Wood Buffalo National Park in Canada, and Patuxent Wildlife Research Center have established a captive flock of whooping cranes, and at least two additional wild populations. Efforts have focused on research, habitat protection, law enforcement,...
Organochlorines and mercury in eggs of coastal terns and herons in California, USA
H. M. Ohlendorf, T. W. Custer, Roy W. Lowe, M. Rigney, E. Cromartie
1988, Colonial Waterbirds (11) 85-94
In San Franciso Bay, California, USA, concentrations of DDE and mercury in eggs differed among Caspian Tern, Forster's Tern, Black-crowned Night-Heron, and Snowy Egret in 1982. Geometric mean DDE concentrations were higher (P < 0.05) in Caspian Tern eggs (6.93 ppm, wet weight) than in eggs of other species (1.92-2.84...
Reproductive effects of nest-marking studies in an American white pelican colony
D.E. Boellstorff, D. W. Anderson, H. M. Ohlendorf, E.J. O’Neill
1988, Colonial Waterbirds (11) 215-219
In 1981 and 1982 we studied the reproductive success of American White Pelicans in the Klamath Basin of northern California. We observed that reproductive success at one colony became reduced in 1981 when we entered that colony to collect eggs for chemical analysis and to mark nests for an...
Organochlorine residues in great blue herons from the northwestern United States
R. E. Fitzner, L. J. Blus, Charles J. Henny, D.W. Carlile
1988, Colonial Waterbirds (11) 293-300
We collected eggs or young Great Blue Herons from eight nesting colonies in the northwestern United States from 1977 through 1982. Subadults were collected at three estuarine areas in Puget Sound in 1981 and dead young or adults were collected at various localities. Nearly all samples analyzed contained organochlorine...
Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography
A. A. Belisle, D. M. Swineford
1988, Environmental Toxicology and Chemistry (7) 749-752
A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetonermethylene chloride (1:1, v/v). Coextracted water was removed by additional sodium sulfate packed below the...