Methodologies that detect biologically active substances have important potential applications for medical diagnostics, drug discovery, and chemical and biological anti-terrorism efforts. The wide spectrum of potential analytes that induce a physiological response dictates that novel techniques be developed to more rapidly screen and characterize agents that are more economical and...
Understanding the drivers of species occurrence is a fundamental goal in basic and applied ecology. Occupancy models have emerged as a popular approach for inferring species occurrence because they account for problems associated with imperfect detection in field surveys. Current models, however, are limited because they assume covariates are independent...
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Understanding the drivers of species occurrence is a fundamental goal in basic and applied ecology. Occupancy models have emerged as a popular approach for inferring species occurrence because they account for problems associated with imperfect detection in field surveys. Current models, however, are limited because they assume covariates are independent...
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Methods & Research R-253:226–284.
Pearl, J. 2000. Causality. Cambridge, New York.
Preston, D. L., J. S
Understanding the drivers of species occurrence is a fundamental goal in basic and applied ecology. Occupancy models have emerged as a popular approach for inferring species occurrence because they account for problems associated with imperfect detection in field surveys. Current models, however, are limited because they assume covariates are independent...
Describing the mechanisms that drive variation in species interaction strengths is central to understanding, predicting, and managing community dynamics. Multiple factors have been linked to trophic interaction strength variation, including species densities, species traits, and abiotic factors. Yet most empirical tests of the relative roles of multiple mechanisms that drive...
High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a long-term data set on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have shifted 7 days earlier over...
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, Diane M. McKnight2,4, Mark W. Williams2,3, 7
Katherina Hell2, Matthew P. Miller5, Sarah J. Hart3
High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a long-term data set on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have shifted 7 days earlier over...
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Citation:
Preston, D. L., N. Caine, D. M. McKnight,
M. W. Williams, K. Hell, M. P. Miller,
S. J. Hart, and
High-elevation aquatic ecosystems are highly vulnerable to climate change, yet relatively few records are available to characterize shifts in ecosystem structure or their underlying mechanisms. Using a long-term data set on seven alpine lakes (3126 to 3620 m) in Colorado, USA, we show that ice-off dates have shifted 7 days earlier over...
Numerous tests were applied to rainbow trout
of eleven months of age to determine whether
ascorbic acid is an essential element of the diet
of these fish. Although previous work had been
done on this question, conflicts in the results,
the large reliance upon abnormal symptoms such as
lordosis and...
Reduction of pocket gopher damage to conifer seedlings is important to successful reforestation in many regions of the Pacific
Northwest. The objective of this study was to determine the factors that influence the local distribution of the northern pocket gopher (Thomomys talpoides Richardson) in a forested region of south-central Oregon....
The role of each habitat fish use is of great importance to the dynamics of populations. During
their early marine residence, Chinook salmon (Oncorhynchus tshawytscha), an anadromous fish
species, mostly inhabit estuaries but also use sandy beach surf zones and the coastal ocean.
However, the role of surf zones in...
Large quantities of smaller diameter materials are available in the overstocked forests of eastern Oregon and Washington, but the costs of removing these materials and the long distances from markets sharply reduce the potential of this resource. Failure to thin these forests will sharply increase the likelihood of catastrophic wildfires....
The inter-relationships among δ¹³C and δ¹⁸O in tree ring cellulose and ring width have the potential to illuminate long-term physiological and environmental information in forest stands that have not been monitored. We examine how within-stand competition and environmental gradients affect ring widths and the stable isotopes of cellulose. We utilize...
The wine grape industry is rapidly growing in Oregon. By the year 2005, we could predict that Oregon will have over 10,000 acres in wine grape production. At a meeting last year, the Grapevine Improvement Committee acknowledged that little was known about the presence of potential pest and beneficial insects...
The behavior of low-frequency baroclinic Rossby wave motion in the vicinity of coastal boundaries is investigated using linearized modulated wave theory in a stratified, constant-depth, equatorial β-plane ocean. A primary objective is to obtain an equation that describes large-scale, low-frequency pressure fluctuations along variable geometry ocean boundaries at all latitudes...
The Northwest Lau Backarc Basin, consisting of the Northwest Lau Spreading Center (NWLSC) and the Rochambeau Rifts (RR), is unique in having elevated ³He/⁴He ratios (up to 28 R[subscript a]) in the erupted lavas, clearly indicating a hot spot or ocean island basalt (OIB)-type signature. This OIB-type helium signature does...
Stable isotopes can be a valuable tool for tracing the redistribution, storage, and evaporation of water associated with canopy
interception of rainfall. Isotopic differences between throughfall and rainfall have been attributed to three mechanisms:
evaporative fractionation, isotopic exchange with ambient vapor, and temporal redistribution. We demonstrate the potential
importance of...
Sandy beach surf zones serve as alternative nursery habitats for juvenile Chinook salmon (0 age) during their early marine residency, a period considered critical due to high and variable mortality rates. Despite the importance of early marine residence, the extent of juvenile salmon surf zone use and movement along sandy...
Glucose-dependent growth of the luxCDABE reporter bacterium Pseudomonas fluorescens HK44 was monitored noninvasively in quartz sand under unsaturated-flow conditions within a 45- by 56- by 1-cm two-dimensional light transmission chamber. The spatial and temporal development of growth were mapped daily over 7 days by quantifying salicylate-induced bioluminescence. A nonlinear model...
A novel analytical method was developed that permitted real-time, noninvasive measurements of microbial growth and associated changes in hydrodynamic properties in porous media under unsaturated flowing conditions. Salicylate-induced, lux gene-based bioluminescence was used to quantify the temporal and spatial development of colonization over a 7-day time course. Water contents were...
Metal-plate-connected wood trusses with semi-rigid joints were investigated by the matrix method of structural analysis. The element-stiffness matrix and fixed-end forces of an individual member with one or both ends semi-rigid were derived as modifications of the idealized cases. The case of unequal elastic connections at two ends of a...
Strong modulation of turbulent mixing by a westward-propagating tropical instability wave (TIW) was observed in the stratified shear layer between the equatorial undercurrent (EUC) and the surface mixed layer during October and November 2008 at 0°N 140°W. The unique deep diurnal-cycle mixing in the stratified layer beneath the equatorial cold...
Turbulence measurements from the central equatorial Pacific in February 1982 have been analyzed and compared to synoptic CTD and current velocity profiles and current meter data. These suggest considerably more time (if not space) variability than had previously been anticipated. Above 300 m at the equator the turbulence levels were...
Collocated Moderate Resolution Imaging Spectroradiometer (MODIS) imagery and
Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) 532 nm
total attenuated backscatter coefficients were used to identify 50 km scale segments
for ocean regions that had only a single layer of marine stratocumulus. On the basis of
whether the underlying ocean...
A series of profiles of velocity microstructure along 152°E in the western North Pacific Ocean were collected in May–June 1982. Large, averaged turbulent dissipation rates, ϵ, found in the main thermocline (400 to 1000 m) were determined by a combination of large independent estimates of ϵ and a greater rate...
Current and hydrographic observations from the Coastal Mixing and Optics
experiment moored array, deployed from August 1996 through June 1997, are used to
describe the velocity variability and evaluate the dynamics of circulation over the New
England shelf on timescales ranging from a few days to several months. Subtidal (days...
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on the New
England shelf’’
R. Kipp Shearman and Steven J. Lentz
Received 22 December 2006
Current and hydrographic observations from the Coastal Mixing and Optics
experiment moored array, deployed from August 1996 through June 1997, are used to
describe the velocity variability and evaluate the dynamics of circulation over the New
England shelf on timescales ranging from a few days to several months. Subtidal (days...
Full Text:
on the New
England shelf’’
R. Kipp Shearman and Steven J. Lentz
Received 22 December 2006
Current and hydrographic observations from the Coastal Mixing and Optics experiment moored array, deployed from August 1996 through June 1997, are used to describe the velocity variability and evaluate the dynamics of circulation over the New England shelf on timescales ranging from a few days to several months. Subtidal (days...
Hydrothermal vents appear to be the tip of the subsurface biosphere in the ocean crust. The primary prducers in this biosphere are prokaryotes that tolerate a wide variety of physical and chemical conditions and are versatile in their use of inorganic compounds to drive metabolism. A synthesis of chemical and...
We apply GENMOM, a coupled atmosphere–ocean climate model, to simulate eight equilibrium time
slices at 3000-year intervals for the past 21,000 years forced
by changes in Earth–Sun geometry, atmospheric greenhouse
gases (GHGs), continental ice sheets, and sea level. Simulated
global cooling during the Last Glacial Maximum
(LGM) is 3.8°C and...
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coupled atmosphere–ocean model
J. R. Alder and S. W. Hostetler
Correspondence to:J. R. Alder (jalder
We apply GENMOM, a coupled atmosphere–ocean climate model, to simulate eight equilibrium time
slices at 3000-year intervals for the past 21,000 years forced
by changes in Earth–Sun geometry, atmospheric greenhouse
gases (GHGs), continental ice sheets, and sea level. Simulated
global cooling during the Last Glacial Maximum
(LGM) is 3.8°C and...
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Alder, J. R., & Hostetler, S. W. (2015). Global climate simulations at 3000 year
intervals for the last
Annual recruitment of the New Zealand longfin eel (Anguilla dieffenbachii) has decreased by around 75 percent since heavy levels of commercial fishing began in the early 1970s. Given the unsustainability of existing regulatory policy, a deterministic multiple-cohort bioeconomic model is developed and applied to this system to gain insight into...
The yields of over 200 projectile-like fragments (PLFs) and target-like fragments (TLFs) from the interaction of (E[subscript]c.m.=450 MeV) Xe¹³⁶ with a thick target of Pb²⁰⁸ were measured using Gammasphere and off-line γ-ray spectroscopy, giving a comprehensive picture of the production cross sections in this reaction. The measured yields were compared...
We have implemented the USGS National Climate Change Viewer (NCCV), which is an easy-to-use web application that displays future projections from global climate models over the United States at the state, county and watershed scales. We incorporate the NASA NEX-DCP30 statistically downscaled temperature and precipitation for 30 global climate models...
We apply GENMOM, a coupled atmosphere–ocean climate model, to simulate eight equilibrium time slices at 3000-year intervals for the past 21,000 years forced by changes in Earth–Sun geometry, atmospheric greenhouse gases (GHGs), continental ice sheets, and sea level. Simulated global cooling during the Last Glacial Maximum (LGM) is 3.8°C and...
A system of quasilinear degenerate parabolic equations arising in the modeling of diffusion in a fissured medium is studied. There is one such equation in the local cell coordinates at each point of the medium, and these are coupled through a similar equation in the global coordinates. It is shown...
Transmission dynamics of the actinospore stage of Ceratomyxa shasta to the salmonid host were investigated under field and laboratory conditions. The number of parasites transmitted and the transmission rate were compared between 2 different exposure durations and also among different water velocities, by means of field exposures. Under laboratory conditions,...
Sea surface temperature variations along the entire U.S. East Coast from 1875 to 2007 are characterized using a collection of historical observations from lighthouses and lightships combined with recent buoy and shore-based measurements. Long-term coastal temperature trends are warming in the Gulf of Maine [1.0° ± 0.3°C (100 yr)⁻¹] and...
Vertically propagating coastal internal Kelvin waves (IKWs) forward by the alongshore component of the wind at the coast are studied, utilizing an ƒ-plane model of a continuously stratified ocean with a vertical eastern boundary. With an infinitely deep ocean, several initial value problems that illustrate the basic properties of the...
Along the west Coast of North America, the response of sea level to fluctuations in alongshore wind stress at large alongshore scales (> 1000 km) accounted for a substantial faction of the total sea level variance during summer 1973. Space-time contour plots of sea level and alongshore stress show that...
A simple parameterization of mixing processes originally developed by Kraus and Turner (1967) is included in a two-dimensional, two-layer theory of wind-driven coastal upwelling. Mixed-layer deepening is a competition between entrainment due to wind stirring, stabilization due to surface beating, and upwelling vertical velocity. For longshore winds favorable to upwelling,...
A theory of a two-dimensional wind-driven diabatic ocean mixed layer with strong horizontal gradients is formulated analytically. An equation that allows the relaxation of the strict Ekman balance—Coriolis force against wind stress—is derived from a careful consideration of the cross-gradient momentum balance. The relaxation scale depends implicitly on mixed-layer depth...
Peak discharge estimates are fundamental in the design of hydraulic structures, embankment protection, and stream restoration efforts, as well as flood risk analysis. Historic stream gage records are commonly used in the development of peak discharge estimates for a particular watershed. Use of an entire stream gage record assumes hydrologic...
Trapping migrating steelhead trout smolts was done in the spring and early summers of 1991 and 1992 as part of the 1990 Umpqua National Forest Land and Resource Management Plan. Calf Creek was monitored to "validate smolt output estimates" and to "determine if changes in habitat quality are occurring." (Introduction)
Observations from the Coastal Mixing and Optics experiment moored array, deployed from August 1996 through June 1997, are used to describe barotropic and baroclinic tidal variability over the New England shelf. The dominant M₂ tidal elevations decrease toward the northeast to a minimum over the Nantucket shoals (about 34 cm),...
Current and hydrographic observations from the Coastal Mixing and Optics experiment moored array, deployed from August 1996 through June 1997, are used to describe the velocity variability and evaluate the dynamics of circulation over the New England shelf on timescales ranging from a few days to several months. Subtidal (days...
Observations from the Coastal Mixing and Optics experiment moored array, deployed
from August 1996 through June 1997, are used to describe barotropic and baroclinic
tidal variability over the New England shelf. The dominant M₂ tidal elevations decrease
toward the northeast to a minimum over the Nantucket shoals (about 34 cm),...
In shallow water, any two waves of the same frequency are shown to produce complex patterns of
drift velocity above the sea bed. If the longshore components λ₁, λ₂ of the wave numbers of the two
waves are different, these steady flow patterns exhibit a longshore periodicity of wave number...
Synchronous runup records were collected from 14 locations spaced irregularly over a 7 km stretch of
a low-slope beach. The significant runup height, herein defined as the significant vertical excursion of
water level at the shoreline, was typically 2 m, 60% of the incident significant wave height at the
breakpoint....
Satellite ocean color data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) were used to examine distributions of chlorophyll concentration within the Southern Ocean for the period of October 1997 through September 1998. Over most of the Southern Ocean, mean chlorophyll concentrations remained quite low (<0.3-0.4 mg m¯³). Phytoplankton blooms where...
The interactive impact of overstory canopy closure, understory brush control, and simulated white-tailed deer (Odocoileus virginianus Zimmermann) herbivory (i.e., clipping) on growth and survival of underplanted white pine (Pinus strobus L.) seedlings was examined. Clipping was conducted in April 1996 and 1997 at three intensities (control, 0% previous year’s growth...
High concentrations of the fumigant methylisothiocyanate (MITC) will effectively control decay fungi in large wood structures, but the fungitoxicity of low MITC concentrations and the influence of wood moisture content (MC) on its performance are not well understood. The MC of Douglas-fir heartwood greatly influenced the susceptibility of the decay...
The influence of moisture content (MC) and conventional preservative treatment on methylisothiocyanate (MIT) sorption and diffusion were investigated in Douglas-fir wood. In wood at 0% MC, the ratio of equilibrium MIT adsorption to desorption concentrations was low (0.2), but it increased rapidly to about 0.94 above 18% MC. Partition coefficients...
A closed-tube bioassay with Poria placenta was used to measure residual fungistatic vapors in wood fumigated with methylisothiocyanate (MIT). This bioassay showed an inverse linear relationship between fungal growth and the amount of MIT in the wood samples. For fumigated increment-core sections of unseasoned Douglas-fir heartwood (4.8 mm in diameter...
Aerial photo cruising that can be accomplished quickly, cheaply and with a satisfactory degree of accuracy has been the goal of many forest mensurationists throughout the world. As early as 1925, photo cruising was accomplished successfully by Professor R. Hugershoff and his associates in Germany. The development of this technique...
The relationships between beam attenuation spectra, chlorophyll and pheophytin pigment concentrations, and particle size distributions are examined for a coastal region (Monterey Bay area) believed to have negligible concentrations of terrestrially derived dissolved organic compounds (during May 1977) but large quantities of phytoplankton and resuspended sediments. It was found that...
Heat and salt balances over the New England shelf are examined using 10 month time
series of currents, temperature, and salinity from a four element moored array and surface
heat and freshwater fluxes from a meteorological buoy. A principal result is closure of
the heat budget to 10 W m−2....
Nitrobacter hamburgensis X14 is a facultative lithoautotroph that conserves energy from the
oxidation of nitrite (NO
2 ) and fixes carbon dioxide (CO2) as its sole source of carbon. The
availability of the N. hamburgensis X14 genome sequence initiated a re-examination of its
mixotrophic and organotrophic potential, as genes encoding...
Throughout the western United States, the invasive annual grass, medusahead (Taeniatherum caput-medusae L. Nevski), is rapidly invading grasslands once dominated by native perennial grasses, such as bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A). It is also invading grasslands dominated by less undesirable invasive annual grasses, especially cheatgrass (Bromus tectorum L.). Understanding...
Deformation of metallic glasses requires the existence of free volume to allow atomic movement under mechanical loading. Accordingly, quantification of the free volume state of the alloy is crucial to understand it's mechanical behavior. By annealing below the glass transition temperature, the free volume of a Zr₄₄Ti₁₁Ni₁₀Cu₁₀Be₂₅ bulk metallic glass...
Highly transparent ZnO-based thin-film transistors (TFTs) are fabricated with optical transmission (including substrate) of ~75% in the visible portion of the electromagnetic spectrum. Current–voltage measurements indicate n-channel, enhancement-mode TFT operation with excellent drain current saturation and a drain current on-to-off ratio of ~10⁷. Threshold voltages and channel mobilities of devices...