Fabricating data: How substituting values for nondetects can ruin results, and what can be done about it
D.R. Helsel
2006, Chemosphere (65) 2434-2439
The most commonly used method in environmental chemistry to deal with values below detection limits is to substitute a fraction of the detection limit for each nondetect. Two decades of research has shown that this fabrication of values produces poor estimates of statistics, and commonly obscures patterns and trends in...
Lithostratigraphy and shear-wave velocity in the crystallized Topopah Spring Tuff, Yucca Mountain, Nevada
D.C. Buesch, K.H. Stokoe II, K.C. Won, Y.J. Seong, J.L. Jung, M.D. Schuhen
2006, Conference Paper, Proceedings of the 11th International High Level Radioactive Waste Management Conference, IHLRWM
Evaluation of the potential future response to seismic events of the proposed spent nuclear fuel and high-level radioactive waste repository at Yucca Mountain, Nevada, is in part based on the seismic properties of the host rock, the 12.8-million-year-old Topopah Spring Tuff. Because of the processes that formed the tuff, the...
Fate of fish production in a seasonally flooded saltmarsh
Philip W. Stevens, C.L. Montague, K. J. Sulak
2006, Marine Ecology Progress Series (327) 267-277
Although saltmarshes are thought to enhance the productivity of open estuarine waters, the mechanism by which energy transfer occurs has been debated for decades. One possible mechanism is the transfer of saltmarsh production to estuarine waters by vagile fishes and invertebrates. Monthly estimates of fish standing stock, net fish ingress,...
Evaluation of aerial survey methods for Dall's sheep
Mark S. Udevitz, Brad S. Shults, Layne G. Adams, Christopher Kleckner
2006, Wildlife Society Bulletin (34) 732-740
Most Dall's sheep (Ovis dalli dalli) population-monitoring efforts use intensive aerial surveys with no attempt to estimate variance or adjust for potential sightability bias. We used radiocollared sheep to assess factors that could affect sightability of Dall's sheep in standard fixed-wing and helicopter surveys and to evaluate feasibility of methods...
Airport geomagnetic surveys in the United States
A. Berarducci
2006, NATO Security through Science Series C: Environmental Security 247-258
The Federal Aviation Administration (FAA) and the United States military have requirements for design, location, and construction of compass calibration pads (compass roses), these having been developed through collaboration with US Geological Survey (USGS) personnel. These requirements are detailed in the FAA Advisory Circular AC 150/5300-13, Appendix 4, and in...
International symposium on airborne geophysics
T. Mogi, H. Ito, H. Kaieda, K. Kusunoki, R. W. Saltus, D.V. Fitterman, S. Okuma, T. Nakatsuka
2006, Conference Paper, Eos
[No abstract available]...
Denitrification potential of different land-use types in an agricultural watershed, lower Mississippi valley
S. Ullah, S.P. Faulkner
2006, Ecological Engineering (28) 131-140
Expansion of agricultural land and excessive nitrogen (N) fertilizer use in the Mississippi River watershed has resulted in a three-fold increase in the nitrate load of the river since the early 1950s. One way to reduce this nitrate load is to restore wetlands at suitable locations between croplands and receiving...
Virulence comparisons of infectious hematopoietic necrosis virus U and M genogroups in sockeye salmon and rainbow trout
K.A. Garver, W.N. Batts, Gael Kurath
2006, Journal of Aquatic Animal Health (18) 232-243
Infectious hematopoietic necrosis virus (IHNV) is an aquatic rhabdovirus that infects salmonids in the Pacific Northwest of the United States, Europe, and Asia. Isolates of IHNV have been phylogenetically classified into three major viral genogroups, designated U, M, and L. To characterize virulence of IHNV in the context of these...
Global phylogeographic limits of Hawaii's avian malaria
J.S. Beadell, F. Ishtiaq, R. Covas, M. Melo, B.H. Warren, C. T. Atkinson, S. Bensch, G.R. Graves, Y.V. Jhala, M.A. Peirce, A.R. Rahmani, D.M. Fonseca, R.C. Fleischer
2006, Proceedings of the Royal Society B: Biological Sciences (273) 2935-2944
The introduction of avian malaria (Plasmodium relictum) to Hawaii has provided a model system for studying the influence of exotic disease on naive host populations. Little is known, however, about the origin or the genetic variation of Hawaii's malaria and traditional classification methods have confounded attempts to place the parasite...
Findings of the Mars Special Regions Science Analysis Group
D.W. Beaty, K.L. Buxbaum, M.A. Meyer, N. Barlow, W. Boynton, B. Clark, J. Deming, P.T. Doran, K. Edgett, S. Hancock, J. Head, M. Hecht, V. Hipkin, T. Kieft, R. Mancinelli, E. McDonald, C. McKay, M. Mellon, H. Newsom, G. Ori, D. Paige, A.C. Schuerger, M. Sogin, J.A. Spry, A. Steele, K. Tanaka, M. Voytek
2006, Astrobiology (6) 677-732
In summary, within the upper 5 m most of Mars is either too cold or too dry to support the propagation of terrestrial life. However, there are regions that are in disequilibrium, naturally or induced, and could be classified as "special" or, if enough uncertainty exist, could not be declared...
Imaging the transition from Aleutian subduction to Yakutat collision in central Alaska, with local earthquakes and active source data
D. Eberhart-Phillips, D.H. Christensen, T.M. Brocher, R. Hansen, N.A. Ruppert, Peter J. Haeussler, G.A. Abers
2006, Journal of Geophysical Research B: Solid Earth (111)
In southern and central Alaska the subduction and active volcanism of the Aleutian subduction zone give way to a broad plate boundary zone with mountain building and strike-slip faulting, where the Yakutat terrane joins the subducting Pacific plate. The interplay of these tectonic elements can be best understood by considering...
Pathogens, nutritional deficiency, and climate influences on a declining moose population
D.L. Murray, E.W. Cox, W.B. Ballard, Heather A. Whitlaw, M.S. Lenarz, T. W. Custer, T. Barnett, T.K. Fuller
2006, Wildlife Monographs 1-30
Several potential proximate causes may be implicated in a recent (post-1984) decline in moose (Alces alces andersoni) numbers at their southern range periphery in northwest Minnesota, USA. These causes include deleterious effects of infectious pathogens, some of which are associated with white-tailed deer (Odocoileus virginianus), negative effects of climate change,...
Incorporating diverse data and realistic complexity into demographic estimation procedures for sea otters
M. Timothy Tinker, Daniel F. Doak, James A. Estes, Brian B. Hatfield, Michelle M. Staedler, Arthur Gross
2006, Ecological Applications (16) 2293-2312
Reliable information on historical and current population dynamics is central to understanding patterns of growth and decline in animal populations. We developed a maximum likelihood-based analysis to estimate spatial and temporal trends in age/sex-specific survival rates for the threatened southern sea otter (Enhydra lutris nereis), using annual population censuses and...
Comprehensive genetic analyses reveal evolutionary distinction of a mouse (Zapus hudsonius preblei) proposed for delisting from the US Endangered Species Act
Tim L. King, John F. Switzer, Cheryl L. Morrison, Michael S. Eackles, Colleen Young, Barbara A. Lubinski, Paul M. Cryan
2006, Molecular Ecology (15) 4331-4359
Zapus hudsonius preblei, listed as threatened under the US Endangered Species Act (ESA), is one of 12 recognized subspecies of meadow jumping mice found in North America. Recent morphometric and phylogenetic comparisons among Z. h. preblei and neighbouring conspecifics questioned the taxonomic status of selected subspecies, resulting in a proposal...
Rupture propagation of the 2004 Parkfield, California, earthquake from observations at the UPSAR
Joe B. Fletcher, P. Spudich, L.M. Baker
2006, Bulletin of the Seismological Society of America (96)
Using a short-baseline seismic array (U.S. Geological Survey Parkfield Dense Seismograph Array [UPSAR]) about 12 km west of the rupture initiation of the 28 September 2004 M 6.0 Parkfield, California, earthquake, we have observed the movement of the rupture front of this earthquake on the San Andreas fault. The sources...
Shrinking ponds in subarctic Alaska based on 1950-2002 remotely sensed images
B. Riordan, D. Verbyla, A. D. McGuire
2006, Journal of Geophysical Research G: Biogeosciences (111)
Over the past 50 years, Alaska has experienced a warming climate with longer growing seasons, increased potential evapotranspiration, and permafrost warming. Research from the Seward Peninsula and Kenai Peninsula has demonstrated a substantial landscape-level trend in the reduction of surface water and number of closed-basin ponds. We investigated whether this...
Integration of the stratigraphic aspects of very large sea-floor databases using information processing
Clinton N. Jenkins, J. Flocks, M. Kulp
Rothwell R.G., editor(s)
2006, Geological Society Special Publication 229-240
Information-processing methods are described that integrate the stratigraphic aspects of large and diverse collections of sea-floor sample data. They efficiently convert common types of sea-floor data into database and GIS (geographical information system) tables, visual core logs, stratigraphic fence diagrams and sophisticated stratigraphic statistics. The input data are held in...
Cloud-to-ground lightning and surface rainfall in warm-season Florida thunderstorms
B. Gungle, E.P. Krider
2006, Journal of Geophysical Research D: Atmospheres (111)
Relationships between cloud-to-ground (CG) lightning and surface rainfall have been examined in nine isolated, warm-season thunderstorms on the east coast of central Florida. CG flashes and the associated rain volumes were measured as a function of time in storm-centered reference frames that followed each storm over a network of rain...
Prevalence of Microsporidia, Cryptosporidium spp., and Giardia spp. in beavers (Castor canadensis) in Massachusetts
R. Fayer, M. Santin, J.M. Trout, S. DeStefano, K. Koenen, T. Kaur
2006, Journal of Zoo and Wildlife Medicine (37) 492-497
Feces from 62 beavers (Castor canadensis) in Massachusetts were examined by fluorescence microscopy (IFA) and polymerase chain reaction (PCR) for Microsporidia species, Cryptosporidium spp., and Giardia spp. between January 2002 and December 2004. PCR-positive specimens were further examined by gene sequencing. Protist parasites were detected in 6.4% of the beavers....
Plasma cholinesterase inhibition in the clay-colored robin (Turdus grayi) exposed to diazinon in maradol papaya crops in Yucatan, Mexico
V.M. Cobos, M.A. Mora, G. Escalona
2006, Revista de Toxicologia (23) 17-21
The use of organophosphorous pesticides in agriculture can result in intoxication of birds foraging in sprayed crops. Effects on birds resulting from pesticide intoxication are varied and include behavioral and reproductive effects, including death. One widely used insecticide in Maradol papaya crops is diazinon which has been associated with various...
Parameterization and simulation of near bed orbital velocities under irregular waves in shallow water
B. Elfrink, D.M. Hanes, B.G. Ruessink
2006, Coastal Engineering (53) 915-927
A set of empirical formulations is derived that describe important wave properties in shallow water as functions of commonly used parameters such as wave height, wave period, local water depth and local bed slope. These wave properties include time varying near-bed orbital velocities and statistical properties such as the distribution...
Using on-site bioassays to determine selenium risk to propagated endangered fishes
Ann L. Allert, James F. Fairchild, Thomas W. May, Linda C. Sappington, N. Darnall, M. Wilson
2006, North American Journal of Fisheries Management (26) 308-316
The Utah Reclamation, Mitigation and Conservation Commission is determining the feasibility of establishing a hatchery and grow-out facility for endangered June suckers Chasmistes liorus at Goshen Warm Springs, Utah. A survey of water quality indicated that selenium and other contaminants may be of concern at Goshen Warm Springs. We conducted...
Coseismic and postseismic slip of the 2004 Parkfield earthquake from space-geodetic data
I.A. Johanson, E.J. Fielding, F. Rolandone, R. Burgmann
2006, Bulletin of the Seismological Society of America (96)
We invert interferometric synthetic aperture radar (InSAR) data jointly with campaign and continuous global positioning system (GPS) data for slip in the coseismic and postseismic periods of the 2004 Parkfield earthquake. The InSAR dataset consists of eight interferograms from data collected by the Envisat and Radarsat satellites spanning the time...
Concentration and dry deposition of mercury species in arid south central New Mexico (2001-2002)
Colleen A. Caldwell, Philip Swartzendruber, Eric Prestbo
2006, Environmental Science & Technology (40) 7535-7540
This research was initiated to characterize atmospheric deposition of reactive gaseous mercury (RGM), particulate mercury (HgP; <2.5 μm), and gaseous elemental mercury (Hg0) in the arid lands of south central New Mexico. Two methods were field-tested to estimate dry deposition of three mercury species. A manual speciation sampling train consisting...
Spectrophotometric properties of materials observed by Pancam on the Mars Exploration Rovers: 2. Opportunity
J. R. Johnson, W.M. Grundy, M.T. Lemmon, J.F. Bell III, M. J. Johnson, R. Deen, R. E. Arvidson, W. H. Farrand, E. Guinness, A. G. Hayes, Kenneth E. Herkenhoff, F. Seelos, J. Soderblom, S. Squyres
2006, Journal of Geophysical Research E: Planets (111)
The Panoramic Camera (Pancam) on the Mars Exploration Rover Opportunity acquired visible/near‐infrared multispectral observations of soils and rocks under varying viewing and illumination geometries that were modeled using radiative transfer theory to improve interpretations of the microphysical and surface scattering nature of materials in Meridiani Planum. Nearly 25,000 individual measurements...
