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 1730, results 43226 - 43250

Show results on a map

Publication Extents

Not all publications have extents, not all extents are completely accurate
Complex dynamics at the interface between wild and domestic viruses of finfish
Gael Kurath, J. Winton
2011, Current Opinion in Virology (1) 73-80
Viral traffic occurs readily between wild and domesticated stocks of finfish because aquatic environments have greater connectivity than their terrestrial counterparts and because the global expansion and dynamic nature of intensive aquaculture provide multiple pathways of transmission and unique drivers of virus adaptation. Supported by examples from the literature, we...
Effects of slow recovery rates on water column geochemistry in aquitard wells
K. E. Schilling
2011, Applied Geochemistry (26) 1108-1114
Monitoring wells are often installed in aquitards to verify effectiveness for preventing migration of surface contaminants to underlying aquifers. However, water sampling of aquitard wells presents a challenge due to the slow recovery times for water recharging the wells, which can take as long as weeks, months or years to...
Evaluating the effects of future climate change and elevated CO2 on the water use efficiency in terrestrial ecosystems of China
Q. Zhu, H. Jiang, C. Peng, J. Liu, X. Wei, X. Fang, S. Liu, G. Zhou, S. Yu
2011, Ecological Modelling (222) 2414-2429
Water use efficiency (WUE) is an important variable used in climate change and hydrological studies in relation to how it links ecosystem carbon cycles and hydrological cycles together. However, obtaining reliable WUE results based on site-level flux data remains a great challenge when scaling up to larger regional zones. Biophysical,...
Salvage logging versus the use of burnt wood as a nurse object to promote post-fire tree seedling establishment
J. Castro, Craig D. Allen, M. Molina-Morales, Sara Maranon-Jimenez, A. Sanchez-Miranda, R. Zamora
2011, Restoration Ecology (19) 537-544
Intense debate surrounds the effects of post-fire salvage logging (SL) versus nonintervention policies on forest regeneration, but scant support is available from experimental studies. We analyze the effect of three post-fire management treatments on the recruitment of a serotinous pine (Pinus pinaster) at a Mediterranean mountain. Treatments were applied 7...
Energetic cost of ichthyophonus infection in Juvenile Pacific Herring (Clupea pallasii)
Johanna J. Vollenweider, J.L. Gregg, R.A. Heintz, P.K. Hershberger
2011, Journal of Parasitology Research (2011)
The energetic costs of fasting and Ichthyophonus infection were measured in juvenile Pacific herring (Clupea pallasii) in a lab setting at three temperatures. Infected herring incurred significant energetic costs, the magnitude of which depended on fish condition at the time of infection (fat versus lean). Herring that were fed continually and were...
An occurrence of the protocetid whale "Eocetus" wardii in the middle Eocene Piney Point Formation of Virginia
Robert E. Weems, Lucy E. Edwards, Jason E. Osborne, A.A. Alford
2011, Journal of Paleontology (85) 271-278
Two protocetid whale vertebrae, here referred to “Eocetus” wardii, have been recovered from the riverbed of the Pamunkey River in east-central Virginia. Neither bone was found in situ, but both were found with lumps of lithified matrix cemented to their surfaces. Most of this matrix was removed and processed for...
Development and application of a pollen-based paleohydrologic reconstruction from the lower Roanoke River Basin, North Carolina, USA
D. Willard, C. Bernhardt, R. Brown, B. Landacre, P. Townsend
2011, The Holocene (21) 305-317
We used pollen assemblages to reconstruct late-Holocene paleohydrologic patterns in floodplain deposits from the lower Roanoke River basin (North Carolina, southeastern USA). Using 120 surface samples from 38 transects, we documented statistical relationships between pollen assemblages, vegetation, and landforms. Backswamp pollen assemblages (long hydroperiods) are dominated by Nyssa (tupelo) and...
Horizontal movements of Atlantic blue marlin (Makaira nigricans) in the Gulf of Mexico
Richard T. Kraus, R.J.D. Wells, J.R. Rooker
2011, Marine Biology (158) 699-713
We examined movements of Atlantic blue marlin (Makaira nigricans) from the Gulf of Mexico based upon 42 pop-up archival transmitting (PAT) tags. Long deployments (including one 334-day track) revealed diverse movement patterns within the Gulf of Mexico. North–south seasonal changes in blue marlin distribution showed strong correspondence with established seasonal...
The characteristics of gas hydrates recovered from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope
H. Lu, Thomas Lorenson, I.L. Moudrakovski, J.A. Ripmeester, Timothy S. Collett, R.B. Hunter, C.I. Ratcliffe
2011, Marine and Petroleum Geology (28) 411-418
Systematic analyses have been carried out on two gas hydrate-bearing sediment core samples, HYPV4, which was preserved by CH4 gas pressurization, and HYLN7, which was preserved in liquid-nitrogen, recovered from the BPXA-DOE-USGS Mount Elbert Stratigraphic Test Well. Gas hydrate in the studied core samples was found by observation to have developed...
USGS 1-min Dst index
J.L. Gannon, Jeffrey J. Love
2011, Journal of Atmospheric and Solar-Terrestrial Physics (73) 323-334
We produce a 1-min time resolution storm-time disturbance index, the USGS Dst, called Dst8507-4SM. This index is based on minute resolution horizontal magnetic field intensity from low-latitude observatories in Honolulu, Kakioka, San Juan and Hermanus, for the years 1985–2007. The method used to produce the index uses a combination of time-...
Spatial variations in focused exhumation along a continental-scale strike-slip fault: The Denali fault of the eastern Alaska Range
J.A. Benowitz, P.W. Layer, P. Armstrong, S.E. Perry, Peter J. Haeussler, P.G. Fitzgerald, S. VanLaningham
2011, Geosphere (7) 455-467
40Ar/39Ar, apatite fission-track, and apatite (U-Th)/He thermochronological techniques were used to determine the Neogene exhumation history of the topographically asymmetric eastern Alaska Range. Exhumation cooling ages range from ~33 Ma to ~18 Ma for 40Ar/39Ar biotite, ~18 Ma to ~6 Ma for K-feldspar minimum closure ages, and ~15 Ma to...
Magnetic properties in an ash flow tuff with continuous grain size variation: a natural reference for magnetic particle granulometry
J.L. Till, M.J. Jackson, J. G. Rosenbaum, P. Solheid
2011, Geochemistry, Geophysics, Geosystems (12)
The Tiva Canyon Tuff contains dispersed nanoscale Fe-Ti-oxide grains with a narrow magnetic grain size distribution, making it an ideal material in which to identify and study grain-size-sensitive magnetic behavior in rocks. A detailed magnetic characterization was performed on samples from the basal 5 m of the tuff. The magnetic...
Geochemical analysis of Atlantic rim water, Carbon County, Wyoming: New applications for characterizing coalbed natural gas reservoirs
J.F. McLaughlin, C.D. Frost, Shruti Sharma
2011, American Association of Petroleum Geologists Bulletin (95) 191-217
Coalbed natural gas (CBNG) production typically requires the extraction of large volumes of water from target formations, thereby influencing any associated reservoir systems. We describe isotopic tracers that provide immediate data on the presence or absence of biogenic natural gas and the identify methane-containing reservoirs are hydrologically confined. Isotopes of...
Successful integration efforts in water quality from the integrated Ocean Observing System Regional Associations and the National Water Quality Monitoring Network
R. Ragsdale, E. Vowinkel, D. Porter, P. Hamilton, R. Morrison, J. Kohut, B. Connell, H. Kelsey, P. Trowbridge
2011, Marine Technology Society Journal (45) 19-28
The Integrated Ocean Observing System (IOOS®) Regional Associations and Interagency Partners hosted a water quality workshop in January 2010 to discuss issues of nutrient enrichment and dissolved oxygen depletion (hypoxia), harmful algal blooms (HABs), and beach water quality. In 2007, the National Water Quality Monitoring Council piloted demonstration projects as...
Thermal erosion of a permafrost coastline: Improving process-based models using time-lapse photography
C. Wobus, R. Anderson, I. Overeem, N. Matell, G. Clow, F. Urban
2011, Arctic, Antarctic, and Alpine Research (43) 474-484
Coastal erosion rates locally exceeding 30 m y-1 have been documented along Alaska's Beaufort Sea coastline, and a number of studies suggest that these erosion rates have accelerated as a result of climate change. However, a lack of direct observational evidence has limited our progress in quantifying the specific processes...
Pigeonholing pyroclasts: Insights from the 19 March 2008 explosive eruption of Kīlauea volcano
Bruce F. Houghton, Don Swanson, R.J. Carey, J. Rausch, Andrew Sutton
2011, Geology (39) 263-266
We think, conventionally, of volcanic explosive eruptions as being triggered in one of two ways: by release and expansion of volatiles dissolved in the ejected magma (magmatic explosions) or by transfer of heat from magma into an external source of water (phreatic or phreatomagmatic explosions). We document here an event...
Direction of unsaturated flow in a homogeneous and isotropic hillslope
N. Lu, B.S. Kaya, J. W. Godt
2011, Water Resources Research (47)
The distribution of soil moisture in a homogeneous and isotropic hillslope is a transient, variably saturated physical process controlled by rainfall characteristics, hillslope geometry, and the hydrological properties of the hillslope materials. The major driving mechanisms for moisture movement are gravity and gradients in matric potential. The latter is solely...
Relationships among rotational and conventional grazing systems, stream channels, and macroinvertebrates
K.L. Raymond, B. Vondracek
2011, Hydrobiologia (669) 105-117
Cattle grazing in riparian areas can reduce water quality, alter stream channel characteristics, and alter fish and macroinvertebrate assemblage structure. The U.S. Department of Agriculture, Natural Resources Conservation Services has recommended Rotational Grazing (RG) as an alternative management method on livestock and dairy operations to protect riparian areas and water...
Consequences of long-distance swimming and travel over deep-water pack ice for a female polar bear during a year of extreme sea ice retreat
George M. Durner, J.P. Whiteman, H.J. Harlow, Steven C. Amstrup, E.V. Regehr, M. Ben-David
2011, Polar Biology (34) 975-984
Polar bears (Ursus maritimus) prefer to live on Arctic sea ice but may swim between ice floes or between sea ice and land. Although anecdotal observations suggest that polar bears are capable of swimming long distances, no data have been available to describe in detail long distance swimming...
Simulating adsorption of U(VI) under transient groundwater flow and hydrochemistry: Physical versus chemical nonequilibrium model
J. Greskowiak, M.B. Hay, H. Prommer, C. Liu, V.E.A. Post, R. Ma, J.A. Davis, C. Zheng, J.M. Zachara
2011, Water Resources Research (47)
Coupled intragrain diffusional mass transfer and nonlinear surface complexation processes play an important role in the transport behavior of U(VI) in contaminated aquifers. Two alternative model approaches for simulating these coupled processes were analyzed and compared: (1) the physical nonequilibrium approach that explicitly accounts for aqueous speciation and instantaneous surface...
Spatiotemporal earthquake clusters along the North Anatolian fault zone offshore Istanbul
Fatih Bulut, William L. Ellsworth, Marco Bohnhoff, Mustafa Aktar, Georg Dresen
2011, Bulletin of the Seismological Society of America (101) 1759-1768
We investigate earthquakes with similar waveforms in order to characterize spatiotemporal microseismicity clusters within the North Anatolian fault zone (NAFZ) in northwest Turkey along the transition between the 1999 İzmit rupture zone and the Marmara Sea seismic gap. Earthquakes within distinct activity clusters are relocated with cross-correlation derived relative travel...
Magmatic-vapor expansion and the formation of high-sulfidation gold deposits: Structural controls on hydrothermal alteration and ore mineralization
Byron R. Berger, Richard W. Henley
2011, Ore Geology Reviews (39) 75-90
High-sulfidation copper–gold lode deposits such as Chinkuashih, Taiwan, Lepanto, Philippines, and Goldfield, Nevada, formed within 1500 m of the paleosurface in volcanic terranes. All underwent an early stage of extensive advanced argillic silica–alunite alteration followed by an abrupt change to spatially much more restricted stages of fracture-controlled sulfide–sulfosalt mineral assemblages...
Volatile abundances and oxygen isotopes in basaltic to dacitic lavas on mid-ocean ridges: The role of assimilation at spreading centers
V.D. Wanless, M.R. Perfit, W.I. Ridley, P.J. Wallace, Craig B. Grimes, E.M. Klein
2011, Chemical Geology (287) 54-65
Most geochemical variability in MOR basalts is consistent with low- to moderate-pressure fractional crystallization of various mantle-derived parental melts. However, our geochemical data from MOR high-silica glasses, including new volatile and oxygen isotope data, suggest that assimilation of altered crustal material plays a significant role in the petrogenesis of dacites...
Nitrous oxide emission from denitrification in stream and river networks
J. J. Beaulieu, J. L. Tank, S. K. Hamilton, W. M. Wollheim, R. O. Hall Jr., P. J. Mulholland, B. J. Peterson, L. R. Ashkenas, L. W. Cooper, Clifford N. Dahm, W. K. Dodds, N. B. Grimm, S. L. Johnson, W. H. McDowell, G. C. Poole, Valett H. Maurice, C. P. Arango, M. J. Bernot, A. J. Burgin, C. L. Crenshaw, A. M. Helton, L. T. Johnson, J. M. O’Brien, J. D. Potter, R.W. Sheibley, D. J. Sobota, S. M. Thomas
2011, Proceedings of the National Academy of Sciences of the United States of America (108) 214-219
Nitrous oxide (N2O) is a potent greenhouse gas that contributes to climate change and stratospheric ozone destruction. Anthropogenic nitrogen (N) loading to river networks is a potentially important source of N2O via microbial denitrification that converts N to N2O and dinitrogen (N2). The...