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

165658 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 2041, results 51001 - 51025

Show results on a map

Publication Extents

Not all publications have extents, not all extents are completely accurate
Rank clocks and plant community dynamics
Scott L. Collins, Katherine Suding, Elsa E. Cleland, Michael Batty, Steven C. Pennings, K.L. Gross, James B. Grace, L. Gough, Joe E. Fargione, Christopher M. Clark
2008, Ecology (89) 3534-3541
Summarizing complex temporal dynamics in communities is difficult to achieve in a way that yields an intuitive picture of change. Rank clocks and rank abundance statistics provide a graphical and analytical framework for displaying and quantifying community dynamics. We used rank clocks, in which the rank order abundance for each...
Effects of landscape gradients on wetland vegetation communities: information for large-scale restoration
Christa L. Zweig, Wiley M. Kitchens
2008, Wetlands (28) 1086-1096
Projects of the scope of the restoration of the Florida Everglades require substantial information regarding ecological mechanisms, and these are often poorly understood. We provide critical base knowledge for Everglades restoration by characterizing the existing vegetation communities of an Everglades remnant, describing how present and historic hydrology affect wetland vegetation...
In-situ observations of the physical properties of the Martian surface
Kenneth E. Herkenhoff, M. P. Golombek, E.A. Guinness, J.B. Johnson, A. Kusack, L. Richter, R.J. Sullivan, S. Gorevan
Jim Bell, editor(s)
2008, Book chapter, The martian surface: Composition, mineralogy, and physical properties
The physical properties of rocks and soils on the surface of Mars have been investigated by several landed spacecraft. Studies of these physical properties constrain interpretation of Martian geologic processes and provide engineering data for future mission planning. As on Earth, these properties vary considerably from place to place, and...
Geometric performance comparison between the OLI and the ETM+
James C. Storey, Mike Choate, Kenton Lee
2008, Conference Paper
The Landsat Data Continuity Mission (LDCM) Operational Land Imager (OLI) is the successor to the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) instrument and features a pushbroom architecture that is more geometrically stable than the whiskbroom scanner of the ETM+. As a tradeoff of this architecture selection, imagery must be...
Forewarned is forearmed! Progress in development of the U.S. National Early Detection and Rapid Response System for invasive plants: Proposal for a North American early warning system for invasive plants
Randy G. Westbrooks
2008, Conference Paper, Proceedings of 2008 Weeds Against Borders
Currently, a National Early Detection and Rapid Response System (EDRR) for Invasive Plants is being developed in the United States. Conceptually, the system is a coordinated framework of local, state, and national interagency groups that is designed to prevent the establishment and spread of new invasive plants through early detection...
High-resolution seismic images and seismic velocities of the San Andreas fault zone at Burro Flats, Southern California
C. C. Tsai, Rufus D. Catchings, Mark R. Goldman, Michael J. Rymer, P. Schnurle, H. W. Chen
2008, Bulletin of the Seismological Society of America (98) 2948-2961
To better understand the structure of the San Andreas fault (SAF) at Burro Flats in southern California, we acquired a three-dimensional combined set of seismic reflection and refraction profiles centered on the main active trace at Burro Flats. In this article, we discuss the variation in shallow-depth velocities along each...
Spirit Mars Rover Mission to the Columbia Hills, Gusev Crater: Mission overview and selected results from the Cumberland Ridge to Home Plate
R. E. Arvidson, S. W. Ruff, R.V. Morris, D. W. Ming, L.S. Crumpler, A. S. Yen, S. W. Squyres, R.J. Sullivan, J.F. Bell III, N.A. Cabrol, B. C. Clark, W. H. Farrand, R. Gellert, R. Greenberger, J. A. Grant, E.A. Guinness, Kenneth E. Herkenhoff, J.A. Hurowitz, J. R. Johnson, G. Klingelhoefer, K. W. Lewis, R. Li, T.J. McCoy, J. Moersch, H.Y. McSween, S.L. Murchie, M. Schmidt, Christian Schroeder, A. Wang, S. Wiseman, M.B. Madsen, W. Goetz, S. M. McLennan
2008, Journal of Geophysical Research E: Planets (113)
This paper summarizes the Spirit rover operations in the Columbia Hills of Gusev Crater from sols 513 to 1476 and provides an overview of selected findings that focus on synergistic use of the Athena Payload and comparisons to orbital data. Results include discovery of outcrops (Voltaire) on Husband Hill that...
Stratigraphic models for deep-water sedimentary systems
Michael H. Gardner, James M. Borer, Brian W. Romans, Noelia Baptista, Erik K. Kling, Diah Hanggoro, Jesse J. Melick, Roger M. Wagerle, Marieke Dechesne, Mary M. Carr, Robert Amerman, Safian Atan
2008, Book chapter, Answering the challenges of production from deep-water reservoirs: Analogues and case histories to aid a new generatio
Stratigraphic models predict sedimentary architecture. Prediction requires understanding systems across a sufficient range of scales. To be predictive a model must address the interaction of multiple process-response relationships. For deep-water systems these processes include (1) subaqueous flow initiation and transformation, (2) linkages between channel, levee and lobe processes, and (3)...
Rapid response of a hydrologic system to volcanic activity: Masaya volcano, Nicaragua
S.C.P. Pearson, C.B. Connor, W. E. Sanford
2008, Geology (36) 951-954
Hydrologic systems change in response to volcanic activity, and in turn may be sensitive indicators of volcanic activity. Here we investigate the coupled nature of magmatic and hydrologic systems using continuous multichannel time series of soil temperature collected on the flanks of Masaya volcano, Nicaragua, one of the most active...
Comparison of effects of humans versus wildlife-detector dogs
Jill S. Heaton, Mary E. Cablk, Kenneth E. Nussear, Todd C. Esque, Philip A. Medica, John C. Sagebiel, S. Steve Francis
2008, Southwestern Naturalist (53) 472-479
The use of dogs (Canis lupus familiaris) trained to locate wildlife under natural conditions may increase the risk of attracting potential predators or alter behavior of target species. These potentially negative effects become even more problematic when dealing with threatened or endangered species, such as the Mojave Desert tortoise (Gopherus...
Diversity increases biomass production for trematode parasites in snails
Ryan F. Hechinger, Kevin D. Lafferty, Armand M. Kuris
2008, Proceedings of the Royal Society B: Biological Sciences (275) 2707-2714
Increasing species diversity typically increases biomass in experimental assemblages. But there is uncertainty concerning the mechanisms of diversity effects and whether experimental findings are relevant to ecological process in nature. Hosts for parasites provide natural, discrete replicates of parasite assemblages. We considered how diversity affects standing-stock biomass for a highly...
Changes in fish diets and food web mercury bioaccumulation induced by an invasive planktivorous fish
Collin A. Eagles-Smith, Thomas H. Suchanek, Arthur E. Colwell, Norman L. Anderson, Peter B. Moyle
2008, Ecological Applications (18) A213-A226
The invasion, boom, collapse, and reestablishment of a population of the planktivorous threadfin shad in Clear Lake, California, USA, were documented over a 20-year period, as were the effects of changing shad populations on diet and mercury (Hg) bioaccumulation in nearshore fishes. Threadfin shad competitively displaced other planktivorous fish in...
Survival and migration behavior of juvenile salmonids at McNary Dam, 2006
2008, Report
During 2006, we used acoustic telemetry and a route-specific survival model (RSSM, Skalski et al. 2002) to estimate behavior, passage, and survival of juvenile salmonids during two different spill operations and diel periods at McNary Dam. An evaluation of 12-h versus 24-h spill was proposed for the spring migration period...
Book review: The ecology and behavior of amphibians
Susan C. Walls
2008, The Quarterly Review of Biology (83)
This state‐of‐the‐art book has made its timely emergence amid a crisis of global magnitude: that of population declines, range reductions, and extinctions of numerous species of amphibians. A clear understanding of the fundamental concepts in amphibian biology is crucial to the success of any conservation effort. This volume compiles the...
The Importance of Uncertainty and Sensitivity Analysis in Process-based Models of Carbon and Nitrogen Cycling in Terrestrial Ecosystems with Particular Emphasis on Forest Ecosystems — Selected Papers from a Workshop Organized by the International Society for Ecological Modelling (ISEM) at the Third Biennal Meeting of the International Environmental Modelling and Software Society (IEMSS) in Burlington, Vermont, USA, August 9-13, 2006
Guy R. Larocque, Jagtar S. Bhatti, Jinxun Liu, James C. Ascough II, Andrew M. Gordon
2008, Ecological Modelling (219) 261-263
Many process-based models of carbon (C) and nitrogen (N) cycles have been developed for terrestrial ecosystems, including forest ecosystems. They address many basic issues of ecosystems structure and functioning, such as the role of internal feedback in ecosystem dynamics. The critical factor in these phenomena is scale, as these processes...
Coast salish and U.S. Geological Survey: Tribal journey water quality project
Sarah K. Akin, Eric E. Grossman, Debra Lekanof, Charles J. O’Hara
2008, Report
The ancestral waters of the Coast Salish People, the Salish Sea, comprise a large inland sea contained within both United States (Puget Sound) and Canadian (Georgia Strait) territory. The Salish Sea is home to more than 220 species of fish, 29 species of marine mammals, more than 40 species of...
Towards continuous 4D microgravity monitoring of volcanoes
Glyn Williams-Jones, Hazel Rymer, Guillaume Mauri, Joachim Gottsmann, Michael P. Poland, Daniele Carbone
2008, Geophysics (73) WA19-WA28
Four-dimensional or time-lapse microgravity monitoring has been used effectively on volcanoes for decades to characterize the changes in subsurface volcanic systems. With measurements typically lasting from a few days to weeks and then repeated a year later, the spatial resolution of theses studies is often at the expense of temporal...
Precipitation, Ground-water Hydrology, and Recharge Along the Eastern Slopes of the Sandia Mountains, Bernalillo County, New Mexico
Kurt J. McCoy, Paul J. Blanchard
2008, Scientific Investigations Report 2008-5179
The spatial and temporal distribution of recharge to carbonate and clastic aquifers along the eastern slopes of the Sandia Mountains was investigated by using precipitation, water-level, dissolved chloride, and specific-conductance data. The U.S. Geological Survey (USGS), in cooperation with the Bernalillo County Public Works Division, conducted a study to assess...
Jurassic-Cretaceous Composite Total Petroleum System and Geologic Assessment of Oil and Gas Resources of the North Cuba Basin, Cuba
U.S. Geological Survey North Cuba Basin Assessment Team
2008, Data Series 69-M
The purpose of the U.S. Geological Survey's (USGS) World Oil and Gas Assessment is to develop geologically based hypotheses regarding the potential for additions to oil and gas reserves in priority areas of the world. The U.S. Geological Survey (USGS) completed an assessment of the undiscovered oil and gas potential...
Comparison of the modified Biot-Gassmann theory and the Kuster-Toksöz theory in predicting elastic velocities of sediments
Myung W. Lee
2008, Scientific Investigations Report 2008-5196
Elastic velocities of water-saturated sandstones depend primarily on porosity, effective pressure, and the degree of consolidation. If the dry-frame moduli are known, from either measurements or theoretical calculations, the effect of pore water on velocities can be modeled using the Gassmann theory. Kuster and Toksoz developed a theory based on...
Analysis of the Magnitude and Frequency of Peak Discharge and Maximum Observed Peak Discharge in New Mexico and Surrounding Areas
Scott D. Waltemeyer
2008, Scientific Investigations Report 2008-5119
Estimates of the magnitude and frequency of peak discharges are necessary for the reliable design of bridges, culverts, and open-channel hydraulic analysis, and for flood-hazard mapping in New Mexico and surrounding areas. The U.S. Geological Survey, in cooperation with the New Mexico Department of Transportation, updated estimates of peak-discharge magnitude...
Technical Review of Water-Resources Investigations of the Tule Desert, Lincoln County, Southern Nevada
David L. Berger, Keith J. Halford, Wayne R. Belcher, Michael S. Lico
2008, Open-File Report 2008-1354
The Nevada State Engineer in Ruling No. 5181 required Lincoln County and Vidler Water Company, Inc., to provide results from additional water-resources studies of Tule Desert in southern Nevada to support water-rights application 64692. As outlined by the ruling, the additional studies were to include the determination of the amount...
Comparison of two cell lysis procedures for recovery of microcystins in water samples from silver lake in Dover, Delaware, with microcystin producing cyanobacterial accumulations
Keith A. Loftin, Michael T. Meyer, Fernando Rubio, Lisa Kamp, Edythe Humphries, Ed Whereat
2008, Open-File Report 2008-1341
A collaboration was developed between Abraxis, LLC, the State of Delaware Department of Natural Resources and Environmental Control Division of Water Resources Environmental Laboratory, the University of Delaware, and the United States Geological Survey to investigate the efficacy of the QuikLyse procedure developed by Abraxis, LLC as an alternative cell-lysis...
EAARL topography-Colonial National Historical Park
John Brock, C. Wayne Wright, Amar Nayegandhi, Sara Stevens, Laurinda J. Travers
2008, Open-File Report 2008-1326
These Lidar-derived topography maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, Florida Integrated Science Center (FISC) St. Petersburg, the National Park Service (NPS) Inventory and Monitoring Program, Northeast Coastal and Barrier Network, and the National Aeronautics and Space Administration (NASA),...