Model selection bias and Freedman's paradox
P.M. Lukacs, K.P. Burnham, David R. Anderson
2010, Annals of the Institute of Statistical Mathematics (62) 117-125
In situations where limited knowledge of a system exists and the ratio of data points to variables is small, variable selection methods can often be misleading. Freedman (Am Stat 37:152-155, 1983) demonstrated how common it is to select completely unrelated variables as highly "significant" when the number of data points...
HiRISE observations of gas sublimation-driven activity in Mars' southern polar regions: III. Models of processes involving translucent ice
Ganna Portyankina, Wojciech J. Markiewicz, Nicolas Thomas, Candice J. Hansen, Moses P. Milazzo
2010, Icarus (205) 311-320
Enigmatic surface features, known as 'spiders', found at high southern martian latitudes, are probably caused by sublimation-driven erosion under the seasonal carbon dioxide ice cap. The Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) has imaged this terrain in unprecedented details throughout southern spring. It has been postulated...
Seismicity and fluid geochemistry at Lassen Volcanic National Park, California: Evidence for two circulation cells in the hydrothermal system
Cathy J. Janik, Marcia K. McLaren
2010, Journal of Volcanology and Geothermal Research (189) 257-277
Seismic analysis and geochemical interpretations provide evidence that two separate hydrothermal cells circulate within the greater Lassen hydrothermal system. One cell originates south to SW of Lassen Peak and within the Brokeoff Volcano depression where it forms a reservoir of hot fluid (235–270°C) that boils to feed steam to the...
Landscape effects on diets of two canids in Northwestern Texas: A multinomial modeling approach
P.R. Lemons, J.S. Sedinger, M.P. Herzog, P. S. Gipson, R.L. Gilliland
2010, Journal of Mammalogy (91) 66-78
Analyses of feces, stomach contents, and regurgitated pellets are common techniques for assessing diets of vertebrates and typically contain more than 1 food item per sampling unit. When analyzed, these individual food items have traditionally been treated as independent, which represents pseudoreplication. When food types are recorded as present or...
Milankovitch-scale correlations between deeply buried microbial populations and biogenic ooze lithology
I.W. Aiello, B.A. Bekins
2010, Geology (38) 79-82
The recent discoveries of large, active populations of microbes in the subseafloor of the world's oceans supports the impact of the deep biosphere biota on global biogeochemical cycles and raises important questions concerning the functioning of these extreme environments for life. These investigations demonstrated that subseafloor microbes are unevenly distributed...
Decadal-timescale estuarine geomorphic change under future scenarios of climate and sediment supply
N. K. Ganju, D. H. Schoellhamer
2010, Estuaries and Coasts (33) 15-29
Future estuarine geomorphic change, in response to climate change, sea-level rise, and watershed sediment supply, may govern ecological function, navigation, and water quality. We estimated geomorphic changes in Suisun Bay, CA, under four scenarios using a tidal-timescale hydrodynamic/sediment transport model. Computational expense and data needs were reduced using the morphological...
Impacts of precipitation seasonality and ecosystem types on evapotranspiration in the Yukon River Basin, Alaska
W. Yuan, S. Liu, H. Liu, J. T. Randerson, G. Yu, L.L. Tieszen
2010, Water Resources Research (46) 1-16
Evapotranspiration (ET) is the largest component of water loss from terrestrial ecosystems; however, large uncertainties exist when estimating the temporal and spatial variations of ET because of concurrent shifts in the magnitude and seasonal distribution of precipitation as well as differences in the response of ecosystem ET to environmental variabilities....
Quality of the log-geometric distribution extrapolation for smaller undiscovered oil and gas pool size
L. Chenglin, Ronald R. Charpentier
2010, Natural Resources Research (19) 11-21
The U.S. Geological Survey procedure for the estimation of the general form of the parent distribution requires that the parameters of the log-geometric distribution be calculated and analyzed for the sensitivity of these parameters to different conditions. In this study, we derive the shape factor of a log-geometric distribution from...
Yearling greater sage-grouse response to energy development in Wyoming
M.J. Holloran, R.C. Kaiser, W.A. Hubert
2010, Journal of Wildlife Management (74) 65-72
Sagebrush (Artemisia spp.)-dominated habitats in the western United States have experienced extensive, rapid changes due to development of natural-gas fields, resulting in localized declines of greater sage-grouse (Centrocercus urophasianus) populations. It is unclear whether population declines in natural-gas fields are caused by avoidance or demographic impacts, or the age classes...
Enzyme stabilization by glass-derived silicates in glass-exposed aqueous solutions
J.A. Ives, J.R. Moffett, P. Arun, D. Lam, T.I. Todorov, A.B. Brothers, D.J. Anick, J. Centeno, M.A.A. Namboodiri, W.B. Jonas
2010, Homeopathy (99) 15-24
Objectives: To analyze the solutes leaching from glass containers into aqueous solutions, and to show that these solutes have enzyme activity stabilizing effects in very dilute solutions. Methods: Enzyme assays with acetylcholine esterase were used to analyze serially succussed and diluted (SSD) solutions prepared in glass and plastic containers. Aqueous...
Using ecological function to develop recovery criteria for depleted species: Sea otters and kelp forests in the Aleutian archipelago
James A. Estes, M. Tim Tinker, James L. Bodkin
2010, Conservation Biology (24) 852-860
Recovery criteria for depleted species or populations normally are based on demographic measures, the goal being to maintain enough individuals over a sufficiently large area to assure a socially tolerable risk of future extinction. Such demographically based recovery criteria may be insufficient to restore the functional roles of strongly interacting...
MTBE, TBA, and TAME attenuation in diverse hyporheic zones
James Landmeyer, Paul M. Bradley, D.A. Trego, K.G. Hale, J.E. Haas II
2010, Ground Water (48) 30-41
Groundwater contamination by fuel-related compounds such as the fuel oxygenates methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA), and tert-amyl methyl ether (TAME) presents a significant issue to managers and consumers of groundwater and surface water that receives groundwater discharge. Four sites were investigated on Long Island, New York, characterized by...
On the specification of structural equation models for ecological systems
James B. Grace, T. Michael Anderson, Han Olff, S.M. Scheiner
2010, Ecological Monographs (80) 67-87
The use of structural equation modeling (SEM) is often motivated by its utility for investigating complex networks of relationships, but also because of its promise as a means of representing theoretical concepts using latent variables. In this paper, we discuss characteristics of ecological theory and some of the challenges for...
Effects of spatial habitat heterogeneity on habitat selection and annual fecundity for a migratory forest songbird
K.L. Cornell, T.M. Donovan
2010, Landscape Ecology (25) 109-122
Understanding how spatial habitat patterns influence abundance and dynamics of animal populations is a primary goal in landscape ecology. We used an information-theoretic approach to investigate the association between habitat patterns at multiple spatial scales and demographic patterns for black-throated blue warblers (Dendroica caerulescens) at 20 study sites in west-central...
First Results of the Regional Earthquake Likelihood Models Experiment
D. Schorlemmer, J.D. Zechar, M.J. Werner, E. H. Field, D.D. Jackson, T.H. Jordan
2010, Pure and Applied Geophysics (167) 859-876
The ability to successfully predict the future behavior of a system is a strong indication that the system is well understood. Certainly many details of the earthquake system remain obscure, but several hypotheses related to earthquake occurrence and seismic hazard have been proffered, and predicting earthquake behavior is a worthy...
Population-level resource selection by sympatric brown and American black bears in Alaska
Jerrold L. Belant, Brad Griffith, Yingte Zhang, Erich H. Follmann, Layne G. Adams
2010, Polar Biology (33) 31-40
Distribution theory predicts that for two species living in sympatry, the subordinate species would be constrained from using the most suitable resources (e.g., habitat), resulting in its use of less suitable habitat and spatial segregation between species. We used negative binomial generalized linear mixed models with fixed effects to estimate...
Microbial arsenic metabolism: New twists on an old poison
J.F. Stolz, P. Basu, Ronald S. Oremland
2010, Microbe (5) 53-59
Phylogenetically diverse microorganisms metabolize arsenic despite its toxicity and are part of its robust iogeochemical cycle. Respiratory arsenate reductase is a reversible enzyme, functioning in some microbes as an arsenate reductase but in others as an arsenite oxidase. As(III) can serve as an electron donor for anoxygenic photolithoautotrophy and chemolithoautotrophy....
Emplacement of the youngest flood lava on Mars: A short, turbulent story
Windy L. Jaeger, Laszlo P. Keszthelyi, James A. Skinner, Moses P. Milazzo, Alfred S. McEwen, Timothy N. Titus, Mark R. Rosiek, Donna M. Galuszka, Elpitha Howington-Kraus, Randolph L. Kirk, the HiRISE TEam
2010, Icarus (205) 230-243
Recently acquired data from the High Resolution Imaging Science Experiment (HiRISE), Context (CTX) imager, and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) onboard the Mars Reconnaissance Orbiter (MRO) spacecraft were used to investigate the emplacement of the youngest flood-lava flow on Mars. Careful mapping finds that...
Bringing wisents back to the Caucasus Mountains: 70 years of a grand mission
Taras Sipko, Sergei Trepet, Peter J. Gogan, Ivan Mizin
2010, European Bison Conservation Newletter (3) 33-44
We describe the history of mountain wisent restoration in the north-west Caucasus region. We review information on wisent during the 18th and 19th centuries, contemporary regional development and reasons for wisent extirpation. We emphasize the key role of the Kuban Hunting Reserve as a main factor in preserving wisent in...
Prescribed fires as ecological surrogates for wildfires: A stream and riparian perspective
R.S. Arkle, D. S. Pilliod
2010, Forest Ecology and Management (259) 893-903
Forest managers use prescribed fire to reduce wildfire risk and to provide resource benefits, yet little information is available on whether prescribed fires can function as ecological surrogates for wildfire in fire-prone landscapes. Information on impacts and benefits of this management tool on stream and riparian ecosystems is particularly lacking....
The release of dissolved nutrients and metals from coastal sediments due to resuspension
Linda H. Kalnejais, William R. Martin, Michael H. Bothner
2010, Marine Chemistry (121) 224-235
Coastal sediments in many regions are impacted by high levels of contaminants. Due to a combination of shallow water depths, waves, and currents, these sediments are subject to regular episodes of sediment resuspension. However, the influence of such disturbances on sediment chemistry and the release of solutes is poorly understood....
On the application of multilevel modeling in environmental and ecological studies
Song S. Qian, Thomas F. Cuffney, Ibrahim Alameddine, Gerard McMahon, Kenneth H. Reckhow
2010, Ecology (91) 355-361
This paper illustrates the advantages of a multilevel/hierarchical approach for predictive modeling, including flexibility of model formulation, explicitly accounting for hierarchical structure in the data, and the ability to predict the outcome of new cases. As a generalization of the classical approach, the multilevel modeling approach explicitly models the hierarchical...
The green alga, Cladophora, promotes Escherichia coli growth and contamination of recreational waters in Lake Michigan
A.V. Heuvel, C. McDermott, R. Pillsbury, T. Sandrin, J. Kinzelman, J. Ferguson, M. Sadowsky, M. Byappanahalli, R. Whitman, G.T. Kleinheinz
2010, Journal of Environmental Quality (39) 333-344
A linkage between Cladophora mats and exceedances of recreational water quality criteria has been suggested, but not directly studied. Th is study investigates the spatial and temporal association between Escherichia coli concentrations within and near Cladophora mats at two northwestern Lake Michigan beaches in Door County, Wisconsin. Escherichia coli concentrations...
Polychlorinated biphenyls, dioxins, furans, and organochlorine pesticides in spotted sandpiper eggs from the upper Hudson River basin, New York
Thomas W. Custer, Christine M. Custer, Brian R. Gray
2010, Ecotoxicology (19) 391-404
In 2004, spotted sandpipers (Actitis macularia) were studied on the Hudson River near Fort Edward south to New Baltimore, NY and on two river drainages that flow into the Hudson River. Concentrations of 28 organochlorine pesticides, 160 polychlorinated biphenyl (PCB) congeners, and 17 dioxin and furan (PCDD-F) congeners...
Predictive modeling of transient storage and nutrient uptake: Implications for stream restoration
Ben L. O’Connor, Miki Hondzo, Judson W. Harvey
2010, Journal of Hydraulic Engineering (136) 1018-1032
This study examined two key aspects of reactive transport modeling for stream restoration purposes: the accuracy of the nutrient spiraling and transient storage models for quantifying reach-scale nutrient uptake, and the ability to quantify transport parameters using measurements and scaling techniques in order to improve upon traditional conservative tracer fitting...
