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The upper Clark Fork River basin in western Montana is widely contaminated by metals from past mining, milling, and smelting activities As part of a comprehensive ecological risk assessment for the upper Clark Fork River, we measured physical and chemical characteristics of surficial sediment samples that were collected from depositional...

A study of U(VI) adsorption by ferrihydrite was conducted over a wide range of U(VI) concentrations, pH, and at two partial pressures of carbon dioxide. A two-site (strong- and weak-affinity sites, FesOH and FewOH, respectively) surface complexation model was able to describe the experimental data well over a wide range...

We can compare natural communities with null models of communities to indicate how they differ from random assemblages of species (i.e., how much structure is present). However, because null models draw on observed values of species' prevalences, whatever structure already exists in natural communities affects the composition of a null...

The Bulldog Mountain vein system, Creede district, Colorado, is one of four major epithermal vein systems from which the bulk of the district's historical Ag-Pb-Zn-Cu production has come. Ores deposited along the vein system were discovered in 1965 and were mined from 1969 to 1985.Six temporally gradational mineralization stages have...

Northern squawfish Ptychocheilus oregonensis cause significant mortality of juvenile salmon in the lower Columbia River Basin (U.S.A.). The effects of light intensity on this predator-prey interaction were examined with laboratory experiments and modelling studies. In laboratory experiments, the rate of capture of subyearling chinook salmon Oncorhynchus tshawytscha by northern squawfish...

Our understanding of predator-prey interactions in fishes has been influenced largely by research assuming that the condition of the participants is normal. However, fish populations today often reside in anthropogenically altered environments and are subjected to many kinds of stressors, which may reduce their ecological performance by adversely affecting their...

A one-dimensional surface energy-balance lake model, coupled to a thermodynamic model of lake ice, is used to simulate variations in the temperature of and evaporation from three Estonian lakes: Karujärv, Viljandi and Kirjaku. The model is driven by daily climate data, derived by cubic-spline interpolation from monthly mean data, and...

A physically based model of variations in δ18O and δ2H in Pyramid Lake is presented. For inputs, the model uses measurements of liquid water inflows and outflows and their associated isotopic compositions and a set of meteorological data (radiative fluxes, air temperature, relative humidity, and windspeed). The model simulates change of lake...

This paper discusses the surface hydrology of a multi‐year simulation of present day climate over the United States (US) conducted with a regional climate model (RegCM) nested within a general circulation model (GCM). The RegCM, which is run with a 60 km gridpoint spacing is interactively coupled with a state‐of‐the‐art...

Positive aeromagnetic anomalies, recent drilling, and models constructed from these data delineate the plutonic roots of the Early Cretaceous Kitakami magmatic arc in northeast Japan. Buried plutons, mostly offshore, produce belts of positive magnetic anomalies. These anomalies and magnetotelluric data suggest that the plutons form a batholith 70–120 km wide,...

Operation of a tide gate installed in the Savannah River by the U.S. Army Corps of Engineers to reduce dredging activities increased salinities upstream in important spawning habitat for striped bass Morone saxatilis. To assess the effects of salinity on survival and growth of striped bass at early life stages, newly...

The most costly American earthquake since 1906 struck Los Angeles on 17 January 1994. The magnitude 6.7 Northridge earthquake resulted from more than 3 meters of reverse slip on a 15-kilometer-long south-dipping thrust fault that raised the Santa Susana mountains by as much as 70 centimeters. The fault appears to...

Pollen assemblages from five mid-Pliocene, deep-marine and shallow-marine sites in the North Atlantic Ocean region were analyzed quantitatively to estimate vegetational composition and terrestrial paleoclimates during a time interval centered at about 3 Ma. Three subarctic sites (58–67°N latitude) from the Norwegian Sea, northern Iceland, and the Labrador Sea yielded...

Garnet-rich xenoliths in a Tertiary dike in the eastern Mojave Desert, California, preserve information about the nature and history of the lower crust. These xenoliths record pressures of ∼ 10–12 kbar and temperatures of ∼ 750–800°C. Approximately 25% have mafic compositions and bear hornblende + plagioclase + clinopyroxene + quartz...

Understanding and predicting global change is a major scientific focus of the late 20th century. Although atmospheric scientists have made substantial progress in developing models that account for many components of the climate system, significant progress is needed in understanding processes associated with the exchange of water, energy, and carbon...

The addition of hydrothermal fluids to heated, intact granite leads to permeability reductions in the temperature range of 300° to 500°C, with the rate of change generally increasing with increasing temperature. The addition of gouge enhances the rate of permeability reduction because of the greater reactivity of the fine material....

The first images of the asteroid 243 Ida from Galileo show an irregular object measuring 56 kilometers by 24 kilometers by 21 kilometers. Its surface is rich in geologic features, including systems of grooves, blocks, chutes, albedo features, crater chains, and a full range of crater morphologies. The largest blocks...

Results from the San Francisco Bay area seismic imaging experiment (BASIX) reveal the presence of a prominent lower crustal reflector at a depth of ∼15 kilometers beneath San Francisco and San Pablo bays. Velocity analyses indicate that this reflector marks the base of Franciscan assemblage rocks and the top of...

A model of stress transfer implies that earthquakes in 1933 and 1952 increased the Coulomb stress toward failure at the site of the 1971 San Fernando earthquake. The 1971 earthquake in turn raised stress and produced aftershocks at the site of the 1987 Whittier Narrows and 1994 Northridge ruptures. The...

This paper attempts to integrate wildlife-related ecologic and economic variables into an econometric model. The model reveals empirical evidence of the presumed interdependence of human-wildlife and the holistic nature of humanity's relationship to the ecosystem. Human use of biologic resources varies not only with income, education, and population, but also...

Factors affecting the efficient transformation of Colletotrichum species. Experimental Mycology, 18, 230-246. Twelve isolates representing four species of Colletotrichum were transformed either by enhanced protoplast, restriction enzyme-mediated integration (REMI), or electroporation-mediated protocols. The enhanced protoplast transformation protocol resulted in 100- and 50-fold increases in the transformation efficiencies of Colletotrichum lindemuthianum...

The regional stratigraphy of eastern Kamchatka includes an exotic, Early-Late Cretaceous ophiolite and Late Cretaceous island-arc volcanic sequence. Integrating the existing geologic and geophysical data, we examine the origin, transport, emplacement, and postemplacement deformation of the island-arc terrane, which is named the Olyutorsky island arc. Results from several paleomagnetic studies...

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Comparison of radar backscatter coefficients (σ°, in dB), calculated by using the empirical model of Oh et al. [1992], to σ° extracted from AIRSAR data of four geologic units at Pisgah shows that the model predicts measured σ°vv and σ°hv to within ±3 dB. The model predicts higher σ°hh than those observed. For...