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Page 1581, results 39501 - 39525

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Bedrock basins in the Sierra Nevada, Alta California
James G. Moore, Mary A. Gorden, Thomas W. Sisson
2012, California Archaeology (4) 99-122
A 360-km-long belt of more than 1,400 meter-sized granitic bedrock basins occurs at 1,200 to 2,500 m elevation on the west flank of the Sierra Nevada. The circular, smooth basins are 0.7 to 1.7 min diameter and are commonly 50 to 1,000 liters in volume. They are man-made as shown by their restricted...
Sources of shaking and flooding during the Tohoku-Oki earthquake: a mixture of rupture styles
Shengji Wei, Robert Graves, Don Helmberger, Jean-Philippe Avouac, Junle Jiang
2012, Earth and Planetary Science Letters (333-334) 91-100
Modeling strong ground motions from great subduction zone earthquakes is one of the great challenges of computational seismology. To separate the rupture characteristics from complexities caused by 3D sub-surface geology requires an extraordinary data set such as provided by the recent Mw9.0 Tohoku-Oki earthquake. Here we combine deterministic inversion and...
Concurrent speciation in the eastern woodland salamanders (Genus Plethodon):DNA sequences of the complete albumin nuclear and partialmitochondrial 12s genes
Richard Highton, Amy Picard Hastings, Catherine Palmer, Richard Watts, Carla A. Hass, Melanie Culver, Stevan Arnold
2012, Molecular Phylogenetics and Evolution (63) 278-290
Salamanders of the North American plethodontid genus Plethodon are important model organisms in a variety of studies that depend on a phylogenetic framework (e.g., chemical communication, ecological competition, life histories, hybridization, and speciation), and consequently their systematics has been intensively investigated over several decades. Nevertheless, we lack a synthesis of...
Repeat surveys of spawning cisco (Coregonus artedi) in western Lake Superior: Timing, distribution and composition of spawning stocks
Daniel L. Yule, Donald R. Schreiner, Peter A. Addison, Michael J. Seider, Lori M. Evrard, Steven A. Geving, Henry R. Quinlan
2012, Advances in Limnology (63) 65-87
Acoustic (AC) and midwater trawl (MT) surveys of spawning cisco (Coregonus artedi) in Lake Superior have been combined with commercial yield to estimate exploitation. To time surveys properly, it is important to understand when adults typically arrive at spawning grounds and how numbers change as the spawning season progresses. We...
Distributional changes of American martens and fishers in eastern North America, 1699-2001: Chapter 4
William B. Krohn
2012, Book chapter, Biology and Conservation of Martens, Sables, and Fishers: A New Synthesis
Contractions in the geographic distributions of the American marten ( Martes americana) and fi sher ( M. pennanti) in eastern North America south of the St. Lawrence River between Colonial times (ca. 1650–1800) and the fi sher’s recent range expansion (ca. 1930–present) are well documented, but causal factors in these...
A Bayesian method to rank different model forecasts of the same volcanic ash cloud: Chapter 24
Roger P. Denlinger, P. Webley, Larry G. Mastin, Hans F. Schwaiger
2012, Book chapter, Lagrangian Modeling of the Atmosphere
Volcanic eruptions often spew fine ash high into the atmosphere, where it is carried downwind, forming long ash clouds that disrupt air traffic and pose a hazard to air travel. To mitigate such hazards, the community studying ash hazards must assess risk of ash ingestion for any flight path and...
Digital elevation model generation from satellite interferometric synthetic aperture radar: Chapter 5
Zhong Lu, Daniel Dzurisin, Hyung-Sup Jung, Lei Zhang, Wonjin Lee, Chang-Wook Lee
2012, Book chapter, Advances in mapping from remote sensor imagery
An accurate digital elevation model (DEM) is a critical data set for characterizing the natural landscape, monitoring natural hazards, and georeferencing satellite imagery. The ideal interferometric synthetic aperture radar (InSAR) configuration for DEM production is a single-pass two-antenna system. Repeat-pass single-antenna satellite InSAR imagery, however, also can be used to...
Genetic variation reveals influence of landscape connectivity on population dynamics and resiliency of western trout in disturbance-prone habitats
Helen M. Neville, Robert E. Gresswell, Jason B. Dunham
2012, Technical Report RMRS-GTR-290
Salmonid fishes have evolved and persisted in dynamic ecosystems where disturbance events vary in frequency, magnitude, timing, and duration, as well as the specific nature of associated effects (e.g., changes in thermal or flow regimes, geomorphology, or water chemistry). In the western United States, one of the major drivers of...
Using computational modeling of river flow with remotely sensed data to infer channel bathymetry
Jonathan M. Nelson, Richard R. McDonald, Paul J. Kinzel, Y. Shimizu
2012, Conference Paper, IAHR Riverflow 2012 Conference Proceedings
As part of an ongoing investigation into the use of computational river flow and morphodynamic models for the purpose of correcting and extending remotely sensed river datasets, a simple method for inferring channel bathymetry is developed and discussed. The method is based on an inversion of the equations expressing conservation...
Aftershocks halted by static stress shadows
Shinji Toda, Ross S. Stein, Gregory C. Beroza, David Marsan
2012, Nature Geoscience (5) 410-413
Earthquakes impart static and dynamic stress changes to the surrounding crust. Sudden fault slip causes small but permanent—static—stress changes, and passing seismic waves cause large, but brief and oscillatory—dynamic—stress changes. Because both static and dynamic stresses can trigger earthquakes within several rupture dimensions of a mainshock, it has proven difficult...
Application of the control volume mixed finite element method to a triangular discretization
Richard L. Naff
2012, International Journal for Numerical Methods in Engineering (89) 846-868
A two‐dimensional control volume mixed finite element method is applied to the elliptic equation. Discretization of the computational domain is based in triangular elements. Shape functions and test functions are formulated on the basis of an equilateral reference triangle with unit edges. A pressure support based on...
Status of pelagic prey fishes in Lake Michigan, 2012
David M. Warner, Timothy P. O’Brien, Steve A. Farha, Randall M. Claramunt, Dale Hanson
2012, Report
Acoustic surveys were conducted in late summer/early fall during the years 1992-1996 and 2001-2012 to estimate pelagic prey fish biomass in Lake Michigan. Midwater trawling during the surveys as well as target strength provided a measure of species and size composition of the fish community for use in scaling acoustic...
Status and trends of prey fish populations in Lake Michigan, 2012
David B. Bunnell, Charles P. Madenjian, Timothy J. Desorcie, Melissa Jean Kostich, Kelley Smith, Jean V. Adams
2012, Report
The U.S. Geological Survey Great Lakes Science Center has conducted lake-wide surveys of the fish community in Lake Michigan each fall since 1973 using standard 12-m bottom trawls towed along contour at depths of 9 to 110 m at each of seven index transects. The resulting data on relative abundance,...
A program for handling map projections of small-scale geospatial raster data
Michael P. Finn, Daniel R. Steinwand, Jason R. Trent, Robert A. Buehler, David M. Mattli, Kristina H. Yamamoto
2012, Cartographic Perspectives (71) 53-67
Scientists routinely accomplish small-scale geospatial modeling using raster datasets of global extent. Such use often requires the projection of global raster datasets onto a map or the reprojection from a given map projection associated with a dataset. The distortion characteristics of these projection transformations can have significant effects on modeling...
Status and trends of pelagic prey fishes in Lake Huron, 2012
David M. Warner, Timothy P. O’Brien, Steve A. Farha, Jeff Schaeffer, Stephen Lenart
2012, Report
The USGS Great Lakes Science Center (GLSC) conducted acoustic/midwater trawl surveys of Lake Huron during 1997 and annually during 2004-2012. The 2012 survey was conducted during September and October, and included transects in Lake Huron’s Main Basin, Georgian Bay, and North Channel. Pelagic fish density (638 fish/ha) was lower in...
Population genetic structure of a widespread coniferous tree, Taxodium distichum [L.] Rich. (Cupressaceae), in the Mississippi River Alluvial Valley and Florida
Ayako Tanaka, Masato Ohtani, Yoshihisa Suyama, Nobuyuki Inomata, Yoshihiko Tsumura, Beth A. Middleton, Hidenori Tachida, Junko Kusumi
2012, Tree Genetics and Genomes (8) 1135-1147
Studies of genetic variation can elucidate the structure of present and past populations as well as the genetic basis of the phenotypic variability of species. Taxodium distichum is a coniferous tree dominant in lowland river flood plains and swamps of the southeastern USA which exhibits morphological variability and adaption to...
Productivity and sedimentary δ15N variability for the last 17,000 years along the northern Gulf of Alaska continental slope
Jason A. Addison, Bruce P. Finney, Walter E. Dean, Maureen H. Davies, Alan C. Mix, John M. Jaeger
2012, Paleoceanography (27)
Biogenic opal, organic carbon, organic matter stable isotope, and trace metal data from a well-dated, high-resolution jumbo piston core (EW0408–85JC; 59° 33.3′N, 144° 9.21′W, 682 m water depth) recovered from the northern Gulf of Alaska continental slope reveal changes in productivity and nutrient utilization over the last 17,000 years. Maximum...
Pyrite–sulfosalt reactions and semimetal fractionation in the Chinkuashih, Taiwan, copper–gold deposit: A 1 Ma paleo-fumarole
R.W. Henley, Byron R. Berger
2012, Geofluids (12) 245-260
The mineralized fracture system that underlay paleo-fumarole field at Chinkuashih, Taiwan has been exposed by copper–gold mining to depths of about 550 m below the paleo-surface. Its mineralogy and systematic variations in metal and semimetal (Fe, Cu, As, Sb, Bi, Hg, Cd, Sn, Zn, Pb, Se, Te, Au, Ag) concentrations provide...
Arsenic-induced biochemical and genotoxic effects and distribution in tissues of Sprague-Dawley rats
Anita K. Patlolla, Todor I. Todorov, Paul B. Tchounwou, Gijsbert van der Voet, Jose A. Centeno
2012, Microchemical Journal (105) 101-107
Arsenic (As) is a well documented human carcinogen. However, its mechanisms of toxic action and carcinogenic potential in animals have not been conclusive. In this research, we investigated the biochemical and genotoxic effects of As and studied its distribution in selected tissues of Sprague–Dawley rats. Four groups of six male...
Environmental and medical geochemistry in urban disaster response and preparedness
Geoffrey S. Plumlee, Suzette A. Morman, A. Cook
2012, Elements (8) 451-457
History abounds with accounts of cities that were destroyed or significantly damaged by natural or anthropogenic disasters, such as volcanic eruptions, earthquakes, wildland–urban wildfires, hurricanes, tsunamis, floods, urban firestorms, terrorist attacks, and armed conflicts. Burgeoning megacities place ever more people in the way of harm from future disasters. In addition...
Mysis diluviana and Hemimysis anomala: reviewing the roles of a native and invasive mysid in the Laurentian Great Lakes region
Maureen G. Walsh, Brent T. Boscarino, Jerome Marty, Ora E. Johannsson
2012, Journal of Great Lakes Research (38) 1-6
Mysis diluviana and Hemimysis anomala are the only two species of mysid shrimps in the order Mysidacea that are present in the Laurentian Great Lakes of North America. M. diluviana has inhabited the deep, cold waters of this region since Pleistocene-era glacial retreat and is widely considered to have a...
Telemetry techniques: A user guide for fisheries research
Noah Adams, John W. Beeman, John H. Eiler, editor(s)
2012, Book
Telemetry provides a powerful and flexible tool for studying fish and other aquatic animals, and its use has become increasingly commonplace. However, telemetry is gear intensive and typically requires more specialized knowledge and training than many other field techniques. As with other scientific methods, collecting good data is dependent on...
Loss and modification of habitat
Francis Lemckert, Stephen Hecnar, David S. Pilliod
2012, Book chapter, Conservation and decline of amphibians: Ecological aspects, effect of humans, and management
Amphibians live in a wide variety of habitats around the world, many of which have been modified or destroyed by human activities. Most species have unique life history characteristics adapted to specific climates, habitats (e.g., lentic, lotic, terrestrial, arboreal, fossorial, amphibious), and local conditions that provide suitable areas for reproduction,...