A multivariate model of plant species richness in forested systems: Old-growth montane forests with a long history of fire
D.C. Laughlin, J.B. Grace
2006, Oikos (114) 60-70
Recently, efforts to develop multivariate models of plant species richness have been extended to include systems where trees play important roles as overstory elements mediating the influences of environment and disturbance on understory richness. We used structural equation modeling to examine the relationship of understory vascular plant species richness to...
Application of artificial neural networks to assess pesticide contamination in shallow groundwater
G.B. Sahoo, C. Ray, E. Mehnert, D.A. Keefer
2006, Science of the Total Environment (367) 234-251
In this study, a feed-forward back-propagation neural network (BPNN) was developed and applied to predict pesticide concentrations in groundwater monitoring wells. Pesticide concentration data are challenging to analyze because they tend to be highly censored. Input data to the neural network included the categorical indices of depth to aquifer material,...
An agreement coefficient for image comparison
Lei Ji, Kevin Gallo
2006, Photogrammetric Engineering and Remote Sensing (72) 823-833
Combination of datasets acquired from different sensor systems is necessary to construct a long time-series dataset for remotely sensed land-surface variables. Assessment of the agreement of the data derived from various sources is an important issue in understanding the data continuity through the time-series. Some traditional measures, including correlation coefficient,...
Orientation-independent measures of ground motion
D.M. Boore, Jennie Watson-Lamprey, N. A. Abrahamson
2006, Bulletin of the Seismological Society of America (96) 1502-1511
The geometric mean of the response spectra for two orthogonal horizontal components of motion, commonly used as the response variable in predictions of strong ground motion, depends on the orientation of the sensors as installed in the field. This means that the measure of ground-motion intensity could differ for the...
Order from noise: Toward a social theory of geographic information
B.S. Poore, N.R. Chrisman
2006, Annals of the Association of American Geographers (96) 508-523
In the so-called Information Age, it is surprising that the concept of information is imprecisely defined and almost taken for granted. Historic and recent geographic information science (GIScience) literature relies on two conflicting metaphors, often espoused by the same author in adjacent paragraphs. The metaphor of invariance, derived from telecommunications...
A new probabilistic seismic hazard assessment for greater Tokyo
R.S. Stein, S. Toda, T. Parsons, E. Grunewald, R. Blong, S. Sparks, H. Shah, J. Kennedy
2006, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences (364) 1965-1988
Tokyo and its outlying cities are home to one-quarter of Japan's 127 million people. Highly destructive earthquakes struck the capital in 1703, 1855 and 1923, the last of which took 105 000 lives. Fuelled by greater Tokyo's rich seismological record, but challenged by its magnificent complexity, our joint Japanese-US group...
Thermal maturity patterns in the Ordovician and Devonian of Pennsylvania using conodont color alteration index (CAI) and vitrinite reflectance (%Ro)
J.E. Repetski, R. T. Ryder, J.A. Harper, M.H. Trippi
2006, Northeastern Geology and Environmental Sciences (28) 266-294
This new series of maps enhances previous thermal maturity maps in Pennsylvania by establishing: 1) new subsurface CAI data points for the Ordovician and Devonian and 2) new %Ro and Rock Eval subsurface data points for Middle and Upper Devonian black shale units. Thermal maturity values for the Ordovician and...
Evaluation of bottom trawls as compared to acoustics to assess adult Lake Herring (Coregonus artedi) abundance in Lake Superior
J.D. Stockwell, D.L. Yule, O. T. Gorman, E.J. Isaac, S.A. Moore
2006, Journal of Great Lakes Research (32) 280-292
We compared density estimates from day bottom trawl tows against night midwater trawl tows and acoustic gear to test the hypothesis that adult lake herring (≥250 mm) are underestimated by day bottom trawl tows during the annual USGS spring fish community survey in Lake Superior. We found average density at...
Blood lead levels of wild Steller's eiders (Polysticta stelleri) and black scoters (Melanitta nigra) in Alaska using a portable blood lead analyzer
Corrine S. Brown, Joanne Luebbert, Daniel M. Mulcahy, Jason L. Schamber, Daniel H. Rosenberg
2006, Journal of Zoo and Wildlife Medicine (37) 361-365
Sea duck populations are declining in Alaska. The reasons for the decline are not known; environmental lead exposure is one suspected cause. Thirty wild Steller's eider ducks (Polysticta stelleri) and 40 wild black scoter ducks (Melanitta nigra) were tested for blood lead levels using a portable blood lead analyzer (LeadCare;...
Use of plume mapping data to estimate chlorinated solvent mass loss
J.R. Barbaro, P.P. Neupane
2006, Ground Water Monitoring and Remediation (26) 115-127
Results from a plume mapping study from November 2000 through February 2001 in the sand-and-gravel surficial aquifer at Dover Air Force Base, Delaware, were used to assess the occurrence and extent of chlorinated solvent mass loss by calculating mass fluxes across two transverse cross sections and by observing changes in...
A robust design mark-resight abundance estimator allowing heterogeneity in resighting probabilities
B.T. McClintock, Gary C. White, K.P. Burnham
2006, Journal of Agricultural, Biological, and Environmental Statistics (11) 231-248
This article introduces the beta-binomial estimator (BBE), a closed-population abundance mark-resight model combining the favorable qualities of maximum likelihood theory and the allowance of individual heterogeneity in sighting probability (p). The model may be parameterized for a robust sampling design consisting of multiple primary sampling occasions where closure need not...
Distribution and relative abundance of forest birds in relation to burn severity in southeastern Arizona
C. Kirkpatrick, C.J. Conway, P.B. Jones
2006, Journal of Wildlife Management (70) 1005-1012
The frequency of wild and prescribed fires in montane forests of the southwestern United States has increased after a century of fire suppression and subsequent fuels accumulation. To assess the effects of recent fires (median time since fire = 6 yr) on the montane forest bird community, we surveyed birds...
Enabling scientific workflows in virtual reality
O. Kreylos, G. Bawden, T. Bernardin, M.I. Billen, E.S. Cowgill, R.D. Gold, B. Hamann, M. Jadamec, L.H. Kellogg, O.G. Staadt, D.Y. Sumner
2006, Conference Paper, Proceedings - VRCIA 2006ACM International Conference on Virtual Reality Continuum and its Applications
To advance research and improve the scientific return on data collection and interpretation efforts in the geosciences, we have developed methods of interactive visualization, with a special focus on immersive virtual reality (VR) environments. Earth sciences employ a strongly visual approach to the measurement and analysis of geologic data due...
One-way coupling of an atmospheric and a hydrologic model in Colorado
L.E. Hay, M.P. Clark, M. Pagowski, G.H. Leavesley, W.J. Gutowski
2006, Journal of Hydrometeorology (7) 569-589
This paper examines the accuracy of high-resolution nested mesoscale model simulations of surface climate. The nesting capabilities of the atmospheric fifth-generation Pennsylvania State University (PSU)-National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) were used to create high-resolution, 5-yr climate simulations (from 1 October 1994 through 30 September 1999), starting...
Filling in the gaps: Modelling native species richness and invasions using spatially incomplete data
C. S. Jarnevich, T.J. Stohlgren, D. Barnett, J. Kartesz
2006, Diversity and Distributions (12) 511-520
Detailed knowledge of patterns of native species richness, an important component of biodiversity, and non-native species invasions is often lacking even though this knowledge is essential to conservation efforts. However, we cannot afford to wait for complete information on the distribution and abundance of native and harmful invasive species. Using...
2480 Ma mafic magmatism in the northern Black Hills, South Dakota: A new link connecting the Wyoming and Superior cratons
P.S. Dahl, M.A. Hamilton, J. L. Wooden, K.A. Foland, R. Frei, J.A. McCombs, D.K. Holm
2006, Canadian Journal of Earth Sciences (43) 1579-1600
The Laramide Black Hills uplift of southwest South Dakota exposes a Precambrian crystalline core of ???2560-2600 Ma basement granitoids nonconformably overlain by two Paleoproterozoic intracratonic rift successions. In the northern Black Hills, a 1 km thick, layered sill (the Blue Draw metagabbro) that intrudes the older rift succession provides a...
Increasing streamflow and baseflow in Mississippi River since the 1940 s: Effect of land use change
Y.-K. Zhang, K. E. Schilling
2006, Journal of Hydrology (324) 412-422
A trend of increasing streamflow has been observed in the Mississippi River (MR) basin since the 1940 s as a result of increased precipitation. Herein we show that increasing MR flow is mainly in its baseflow as a result of land use change and accompanying agricultural activities that occurred in...
Seismic response and damage detection analyses of an instrumented steel moment-framed building
J.E. Rodgers, M. Çelebi
2006, Journal of Structural Engineering (132) 1543-1552
The seismic performance of steel moment-framed buildings has been of particular interest since brittle fractures were discovered at the beam-column connections in a number of buildings following the M 6.7 Northridge earthquake of January 17, 1994. A case study of the seismic behavior of an extensively instrumented 13-story steel moment...
Net carbon exchange across the Arctic tundra-boreal forest transition in Alaska 1981-2000
Catharine Copass Thompson, A. D. McGuire, Joy S. Clein, F. S. Chapin III, J. Beringer
2006, Conference Paper, Mitigation and Adaptation Strategies for Global Change
Shifts in the carbon balance of high-latitude ecosystems could result from differential responses of vegetation and soil processes to changing moisture and temperature regimes and to a lengthening of the growing season. Although shrub expansion and northward movement of treeline should increase carbon inputs, the effects of these vegetation changes...
Seafloor habitat mapping of the New York Bight incorporating sidescan sonar data
R.G. Lathrop, M. Cole, N. Senyk, B. Butman
2006, Estuarine, Coastal and Shelf Science (68) 221-230
The efficacy of using sidescan sonar imagery, image classification algorithms and geographic information system (GIS) techniques to characterize the seafloor bottom of the New York Bight were assessed. The resulting seafloor bottom type map was compared with fish trawl survey data to determine whether there were any discernable habitat associations....
Using self-organizing maps to determine observation threshold limit predictions in highly variant data
C.A. Paganoni, K.C. Chang, M. B. Robblee
2006, Conference Paper, Proceedings of SPIE - The International Society for Optical Engineering
A significant data quality challenge for highly variant systems surrounds the limited ability to quantify operationally reasonable limits on the data elements being collected and provide reasonable threshold predictions. In many instances, the number of influences that drive a resulting value or operational range is too large to enable physical...
Quantifying surface water–groundwater interactions using time series analysis of streambed thermal records: Method development
Christine E Hatch, Andrew T. Fisher, Justin S. Revenaugh, Jim Constantz, Chris Ruehl
2006, Water Resources Research (42)
We present a method for determining streambed seepage rates using time series thermal data. The new method is based on quantifying changes in phase and amplitude of temperature variations between pairs of subsurface sensors. For a reasonable range of streambed thermal properties and sensor spacings the time series method should...
Balancing predation and egg harvest in a colonial seabird: A simulation model
Stephani Zador, John F. Piatt, A. E. Punt
2006, Ecological Modelling (195) 318-326
We developed an individual-based model to study the effects of different regimes of harvesting eggs and natural predation on reproductive success in a colony of the glaucous-winged gull (Larus glaucescens) in Glacier Bay National Park, Alaska. The model incorporates the sequence of egg laying, relaying, and incubation to hatching for...
On the interpretation of energy and energy fluxes of nonlinear internal waves: An example from Massachusetts Bay
A. Scotti, R. Beardsley, B. Butman
2006, Journal of Fluid Mechanics (561) 103-112
A self-consistent formalism to estimate baroclinic energy densities and fluxes resulting from the propagation of internal waves of arbitrary amplitude is derived using the concept of available potential energy. The method can be applied to numerical, laboratory or field data. The total energy flux is shown to be the sum...
Secondary gas emissions during coal desorption, Marathon Grassim Oskolkoff-1 Well, Cook Inlet Basin, Alaska: Implications for resource assessment
C.E. Barker, T. Dallegge
2006, Bulletin of Canadian Petroleum Geology (54) 273-291
Cuttings samples of sub-bituminous humic coals from the Oligocene to Pliocene Tyonek Formation, Cook Inlet Basin, Alaska show secondary gas emissions whose geochemistry is consistent with renewed microbial methanogenesis during canister desorption. The renewed methanogenesis was noted after initial desorption measurements had ceased and a canister had an air and...
