North polar region of Mars: Advances in stratigraphy, structure, and erosional modification
Kenneth L. Tanaka, J. Alexis P. Rodriguez, James A. Skinner, Mary C. Bourke, Corey M. Fortezzo, Kenneth E. Herkenhoff, Eric J. Kolb, Chris Okubo
2008, Icarus (196) 318-358
We have remapped the geology of the north polar plateau on Mars, Planum Boreum, and the surrounding plains of Vastitas Borealis using altimetry and image data along with thematic maps resulting from observations made by the Mars Global Surveyor, Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter spacecraft. New and revised geographic and...
Host mating system and the spread of a disease-resistant allele in a population
D.L. DeAngelis, Jennifer M. Koslow, J. Jiang, S. Ruan
2008, Theoretical Population Biology (74) 191-198
The model presented here modifies a susceptible-infected (SI) host-pathogen model to determine the influence of mating system on the outcome of a host-pathogen interaction. Both deterministic and stochastic (individual-based) versions of the model were used. This model considers the potential consequences of varying mating systems on the rate of spread...
Associations of multi-decadal sea-surface temperature variability with US drought
G.J. McCabe, J.L. Betancourt, S.T. Gray, M.A. Palecki, H.G. Hidalgo
2008, Quaternary International (188) 31-40
Recent research suggests a link between drought occurrence in the conterminous United States (US) and sea surface temperature (SST) variability in both the tropical Pacific and North Atlantic Oceans on decadal to multidecadal (D2M) time scales. Results show that the Atlantic Multidecadal Oscillation (AMO) is the most consistent indicator of...
Magnetic monitoring of earth and space
Jeffrey J. Love
2008, Physics Today (61) 31-37
For centuries, navigators of the world’s oceans have been familiar with an effect of Earth’s magnetic field: It imparts a directional preference to the needle of a compass. Although in some settings magnetic orientation remains important, the modern science of geomagnetismhas emerged from its romantic nautical origins and developed into a subject of great depth and...
Use of complex hydraulic variables to predict the distribution and density of unionids in a side channel of the Upper Mississippi River
J. J. Steuer, T.J. Newton, S. J. Zigler
2008, Hydrobiologia (610) 67-82
Previous attempts to predict the importance of abiotic and biotic factors to unionids in large rivers have been largely unsuccessful. Many simple physical habitat descriptors (e.g., current velocity, substrate particle size, and water depth) have limited ability to predict unionid density. However, more recent studies have found that complex hydraulic...
Hydrated silicate minerals on Mars observed by the Mars Reconnaissance Orbiter CRISM instrument
J.F. Mustard, S.L. Murchie, S.M. Pelkey, B.L. Ehlmann, R.E. Milliken, J. A. Grant, J.-P. Bibring, F. Poulet, J. Bishop, E. N. Dobrea, L. Roach, F. Seelos, R. E. Arvidson, S. Wiseman, R. Green, C. Hash, D. Humm, E. Malaret, J.A. McGovern, K. Seelos, T. Clancy, R. Clark, D. des Marais, N. Izenberg, A. Knudson, Y. Langevin, T. Martin, P. McGuire, Robert Morris, M. Robinson, T. Roush, M. Smith, G. Swayze, H. Taylor, T. Titus, M. Wolff
2008, Nature (454) 305-309
Phyllosilicates, a class of hydrous mineral first definitively identified on Mars by the OMEGA (Observatoire pour la Mineralogie, L’Eau, les Glaces et l’Activitié) instrument1,<a id="ref-link-abstract-2" title="Poulet, F. et...
Cattail invasion of sedge/grass meadows in Lake Ontario: Photointerpretation analysis of sixteen wetlands over five decades
D.A. Wilcox, K.P. Kowalski, H.L. Hoare, M.L. Carlson, H.N. Morgan
2008, Journal of Great Lakes Research (34) 301-323
Photointerpretation studies were conducted to evaluate vegetation changes in wetlands of Lake Ontario and the upper St. Lawrence River associated with regulation of water levels since about 1960. The studies used photographs from 16 sites (four each from drowned river mouth, barrier beach, open embayment, and protected embayment wetlands) and...
Design and evaluation of a simple signaling device for live traps
F.L. Benevides Jr., H. Hansen, S.C. Hess
2008, Journal of Wildlife Management (72) 1434-1436
Frequent checks of live traps require enormous amounts of labor and add human scents associated with repeated monitoring, which may reduce capture efficiency. To reduce efforts and increase efficiency, we developed a trap-signaling device with long-distance reception, durability in adverse weather, and ease of transport, deployment, and use. Modifications from...
Global daily reference evapotranspiration modeling and evaluation
G.B. Senay, J. P. Verdin, R. Lietzow, Assefa M. Melesse
2008, Journal of the American Water Resources Association (44) 969-979
Accurate and reliable evapotranspiration (ET) datasets are crucial in regional water and energy balance studies. Due to the complex instrumentation requirements, actual ET values are generally estimated from reference ET values by adjustment factors using coefficients for water stress and vegetation conditions, commonly referred to as crop coefficients. Until recently,...
A 2650-year-long record of environmental change from northern Yellowstone National Park based on a comparison of multiple proxy data
C. Whitlock, W. Dean, J. Rosenbaum, L. Stevens, S. Fritz, B. Bracht, M. Power
2008, Quaternary International (188) 126-138
Geochemical, stable-isotope, pollen, charcoal, and diatom records were analyzed at high-resolution in cores obtained from Crevice Lake, a varved-sediment lake in northern Yellowstone National Park. The objective was to reconstruct the ecohydrologic, vegetation, and fire history of the watershed for the last 2650 years to better understand past climate variations...
Permeameter data verify new turbulence process for MODFLOW
Eve L. Kuniansky, Keith J. Halford, W. Barclay Shoemaker
2008, Ground Water (46) 768-771
A sample of Key Largo Limestone from southern Florida exhibited turbulent flow behavior along three orthogonal axes as reported in recently published permeameter experiments. The limestone sample was a cube measuring 0.2 m on edge. The published nonlinear relation between hydraulic gradient and discharge was simulated using the turbulent flow...
Viability and fertilizing capacity of cryopreserved sperm from three North American acipenseriform species: A retrospective study
A. Horvath, W.R. Wayman, J.C. Dean, B. Urbanyi, T.R. Tiersch, S.D. Mims, D. Johnson, J.A. Jenkins
2008, Journal of Applied Ichthyology (24) 443-449
Populations of sturgeon across the globe are threatened due to unregulated harvest and habitat loss, and the status varies among species across North America. Ready access to viable and functional sperm would contribute to recovery programmes for these species. In this study, we examined the motility, viability (cell membrane integrity)...
Utilization of protein expression profiles as indicators of environmental impairment of smallmouth bass (Micropterus dolomieu) from the Shenandoah River, Virginia, USA
J. Ripley, L. Iwanowicz, V. Blazer, C. Foran
2008, Environmental Toxicology and Chemistry (27) 1756-1767
The Shenandoah River (VA, USA), the largest tributary of the Potomac River (MD, USA) and an important source of drinking water, has been the site of extensive fish kills since 2004. Previous investigations indicate environmental stressors may be adversely modulating the immune system of smallmouth bass...
Trace-element budgets in the Ohio/Sunbury shales of Kentucky: Constraints on ocean circulation and primary productivity in the Devonian-Mississippian Appalachian Basin
R.B. Perkins, D.Z. Piper, C.E. Mason
2008, Palaeogeography, Palaeoclimatology, Palaeoecology (265) 14-29
The hydrography of the Appalachian Basin in late Devonian-early Mississippian time is modeled based on the geochemistry of black shales and constrained by others' paleogeographic reconstructions. The model supports a robust exchange of basin bottom water with the open ocean, with residence times of less than forty years during deposition...
Physical rock properties in and around a conduit zone by well-logging in the Unzen Scientific Drilling Project, Japan
R. Ikeda, T. Kajiwara, K. Omura, S. Hickman
2008, Journal of Volcanology and Geothermal Research (175) 13-19
The objective of the Unzen Scientific Drilling Project (USDP) is not only to reveal the structure and eruption history of the Unzen volcano but also to clarify the ascent and degassing mechanisms of the magma conduit. Conduit drilling (USDP-4) was conducted in 2004, which targeted the magma conduit for the...
Stress changes from the 2008 Wenchuan earthquake and increased hazard in the Sichuan basin
T. Parsons, C. Ji, E. Kirby
2008, Nature (454) 509-510
On 12 May 2008, the devastating magnitude 7.9 (Wenchuan) earthquake struck the eastern edge of the Tibetan plateau, collapsing buildings and killing thousands in major cities aligned along the western Sichuan basin in China. After such a large-magnitude earthquake, rearrangement of stresses in the crust commonly leads to subsequent damaging...
Numerical modeling of higher order magnetic moments in UXO discrimination
V. Sanchez, L. Yaoguo, M.N. Nabighian, D.L. Wright
2008, IEEE Transactions on Geoscience and Remote Sensing (46) 2568-2583
The surface magnetic anomaly observed in unexploded ordnance (UXO) clearance is mainly dipolar, and consequently, the dipole is the only magnetic moment regularly recovered in UXO discrimination. The dipole moment contains information about the intensity of magnetization but lacks information about the shape of the target. In contrast, higher order...
Effects of weather on survival in populations of boreal toads in Colorado
R. D. Scherer, E. Muths, B.A. Lambert
2008, Journal of Herpetology (42) 508-517
Understanding the relationships between animal population demography and the abiotic and biotic elements of the environments in which they live is a central objective in population ecology. For example, correlations between weather variables and the probability of survival in populations of temperate zone amphibians may be broadly applicable to several...
Patch-reef morphology as a proxy for Holocene sea-level variability, Northern Florida Keys, USA
J. C. Brock, M. Palaseanu-Lovejoy, C. W. Wright, A. Nayegandhi
2008, Coral Reefs (27) 555-568
A portion of the northern Florida Keys reef tract was mapped with the NASA Experimental Advanced Airborne Research Lidar (EAARL) and the morphology of patch reefs was related to variations in Holocene sea level. Following creation of a lidar digital elevation model (DEM), geospatial analyses delineated morphologic attributes of 1,034...
Aquatic insect ecophysiological traits reveal phylogenetically based differences in dissolved cadmium susceptibility
D.B. Buchwalter, D.J. Cain, C.A. Martin, Lingtian Xie, S. N. Luoma, T. Garland Jr.
2008, Proceedings of the National Academy of Sciences of the United States of America (105) 8321-8326
We used a phylogenetically based comparative approach to evaluate the potential for physiological studies to reveal patterns of diversity in traits related to susceptibility to an environmental stressor, the trace metal cadmium (Cd). Physiological traits related to Cd bioaccumulation, compartmentalization, and ultimately susceptibility were measured in 21 aquatic insect species...
The application of electrical conductivity as a tracer for hydrograph separation in urban catchments
B.A. Pellerin, W. M. Wollheim, X. Feng, C.J. Vororsmarty
2008, Hydrological Processes (22) 1810-1818
Two-component hydrograph separation was performed on 19 low-to-moderate intensity rainfall events in a 4.1-km2 urban watershed to infer the relative and absolute contribution of surface runoff (e.g. new water) to stormflow generation between 2001 and 2003. The electrical conductivity (EC) of water was used as a continuous and inexpensive tracer,...
Movement patterns and study area boundaries: Influences on survival estimation in capture-mark-recapture studies
G.E. Horton, B. H. Letcher
2008, Oikos (117) 1131-1142
The inability to account for the availability of individuals in the study area during capture-mark-recapture (CMR) studies and the resultant confounding of parameter estimates can make correct interpretation of CMR model parameter estimates difficult. Although important advances based on the Cormack-Jolly-Seber (CJS) model have resulted in estimators of true survival...
Determining Titan's spin state from Cassini RADAR images
B.W. Stiles, Randolph L. Kirk, R. D. Lorenz, S. Hensley, E. Lee, S.J. Ostro, M.D. Allison, P.S. Callahan, Y. Gim, L. Iess, Del Marmo, G. Hamilton, W.T.K. Johnson, R.D. West
2008, Astronomical Journal (135) 1669-1680
For some 19 areas of Titan's surface, the Cassini RADAR instrument has obtained synthetic aperture radar (SAR) images during two different flybys. The time interval between flybys varies from several weeks to two years. We have used the apparent misregistration (by 10-30 km) of features between separate flybys to construct...
Magnetic fabric of sheared till: A strain indicator for evaluating the bed deformation model of glacier flow
T.S. Hooyer, N.R. Iverson, F. Lagroix, J.F. Thomason
2008, Journal of Geophysical Research F: Earth Surface (113)
Wet-based portions of ice sheets may move primarily by shearing their till beds, resting in high sediment fluxes and the development of subglacial landforms. This model of glacier movement, which requires high bed shear strains, can be tested using till microstructural characteristics that evolve during till deformation. Here we examine...
Modeling the evolution of channel shape: Balancing computational efficiency with hydraulic fidelity
C.W. Wobus, J. W. Kean, G.E. Tucker, R. Scott Anderson
2008, Journal of Geophysical Research F: Earth Surface (113)
The cross-sectional shape of a natural river channel controls the capacity of the system to carry water off a landscape, to convey sediment derived from hillslopes, and to erode its bed and banks. Numerical models that describe the response of a landscape to changes in climate or tectonics therefore require...
