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Fry of rainbow trout Oncorhynchus mykiss were exposed to serotype VR-299 of infectious pancreatic necrosis virus (IPNV) by using a standardized immersion challenge. In concurrent experiments, fish were monitored for 11 d for excretion of IPNV or monitored for 9 d for excretion and transmission of IPNV to...

Maturation of male age-0 Atlantic salmon Salmo salar parr in New England, U.S.A. streams is rare (˜5%), but age-0 parr maturation was high (74%) by autumn in the Sawmill River following a massive, localized flood. Maturation was low in two other study streams (3, 7%) in the same year as the flood,...

There is concern that decreases in stratospheric ozone will lead to hazardous levels of ultraviolet-B (UV-B) radiation at the Earth's surface. In clear water, UV-B may penetrate to significant depths. The purpose of the current study was to compare the sensitivity of freshwater invertebrates to UV-B. We used a solar...

The archaeological site of Quebrada Tacahuay, Peru, dates to 12,700 to 12,500 calibrated years before the present (10,770 to 10,530 carbon-14 years before the present). It contains some of the oldest evidence of maritime- based economic activity in the New World. Recovered materials include a hearth, lithic cutting tools and...

In light of suggestions that the Cascadia subduction margin may pose a significant seismic hazard for the highly populated Pacific Northwest region of the United States, the U.S. Geological Survey (USGS), the Research Center for Marine Geosciences (GEOMAR), and university collaborators collected and interpreted a 530-km-long wide-angle onshore-offshore seismic transect...

Candela et al. (1990, 1992) showed that tides in an open ocean region can be resolved using velocity data from a ship-mounted ADCP. We use their method to build a spatially varying model of the tidal currents in the Gulf of the Farallones, an area of complicated bathymetry where the...

Fossil faeces (coprolites) provide unique trophic perspectives on ancient ecosystems. Yet, although thousands of coprolites have been discovered, specimens that can be unequivocally attributed to carnivorous dinosaurs are almost unknown. A few fossil faeces have been ascribed to herbivorous dinosaurs, but it is more difficult to identify coprolites produced by...

Concern with the redistribution of contaminants associated with sediment in the upper Mississippi River (UMR) arose after the flood of 1993. This project is designed to evaluate the status of sediments in the UMR and is one article in a series designed to assess the extent of sediment contamination in...

No abstract available....

Design and analysis of wildlife habitat selection studies typically do not assess the effect of spatial pattern on the habitat selection process. Effects of landscape scale pattern on habitat selection cannot be accomplished without replicate study areas, because pattern is a single, albeit multifaceted, attribute of an area. For a...

Recent work in seasonally snow covered ecosystems has identified thawed soil and high levels of heterotrophic activity throughout the winter under consistent snow cover. We performed measurements during the winter of 1994 to determine how the depth and timing of seasonal snow cover affect soil microbial populations, surface water NO3/-...

Temperature profoundly influences the physiology and life history characteristics of organisms, particularly in terms of body size. Because so many critical parameters scale with body mass, long-term temperature fluctuations can have dramatic impacts. We examined the response of a small mammalian herbivore, the bushy-tailed woodrat (Neotoma cinerea), to temperature change...

Two ichnofacies are typical of lacustrine depositional systems. The Scoyenia ichnofacies characterizes transitional terrestrial/nonmarine aquatic substrates, periodically inundated or desiccated, and therefore is commonly present in lake margin facies. The Mermia ichnofacies is associated with well oxygenated, permanent subaqueous, fine-grained substrates of hydrologically open, perennial lakes. Bathymetric zonations within the...

Particle friction angles Φ represent the physical resistance to initial movement of a sediment particle and are therefore useful for relating initiation of motion to particular flows. We determined over 8000 friction angle values at five natural rivers by applying a new method that uses a digital load cell to...

Denitrification in riparian soils is thought to be an important factor that reduces hydrologic export of nitrate from forested and agricultural catchments. A 2-y study to identify the soil factors most closely associated with denitrification in riparian soils in headwater catchments within the Catskill Mountains of New York, included field...

Several species of breeding waterfowl have been shown to be exposed to lead shot on the Yukon-Kuskokwim (Y-K) Delta, Alaska. I 'seeded' experimental plots with number 4 lead shot to determine the settlement rate of shot in wetland types commonly used by foraging waterfowl. I resampled plots for 3 years,...

In this study, we reassess crustal contamination and sulfide ore-forming processes in some of the largest magmatic ore deposits, using published Re-Os isotope data and a modeling methodology that incorporates the R factor, defined as the effective mass of silicate magma with which a given mass of sulfide magma has...

Soufriere volcano of St Vincent (<0.6 Ma) is composed of basalts and basaltic andesites, the most mafic of which (mg-number 75) may be representative of the parental magmas of the calc-alkaline suites of the Lesser Antilles arc. Parental, possibly primary, magmas at Soufriere had MgO ∼12.5 wt % and...

Wind, wave and currents measurements at 9 and 14 meter water depths on the shoreface off U.S. Army Corps of Engineers Field Research Facility at Duck, North Carolina are presented. Coastal setup accompanied by southerly-setting alongshore currents and seaward cross-shore currents is developed during Northeasterly storms. Coastal setdown, with reversal...

Transformation twinning in minerals forms isolated twin walls, intesecting walls with corner junctions, and wedge-shaped twins as elements of hierarchical patterns. When cut perpendicular to the twin walls, the twins have characteristic shapes, right-angled and needle-shaped wall traces, which can be observed by transmission electron microscopy or by optical microscopy....

Triploidy induction is a technique that allows genetic manipulation of chromosome number to control reproduction and potentially create faster‐growing animals; however, most methods for inducing polyploidy are not 100% effective. Using sunshine bass (white bass Morone chrysops ♀ × striped bass M. saxatilis ♂) as a model, we cross‐validated the most common verification techniques:...

The robust redhorse, Moxostoma robustum (Teleostei: Catostomidae), is an imperiled sucker native to large rivers of the Atlantic slope of the southeastern United States. Juvenile M. robustum were tested for tolerances to temperature, salinity, pH, and hypoxia in order to evaluate basic early life-history requirements. Static (acute) tests resulted in...

The technique described in this paper represents the modification and combination of two previously existing methods, alkaline fusion and negative thermal ion mass spectrometry (NTIMS). We have used this technique to analyze repeatedly a homogeneous molybdenite powder used as a reference standard in our laboratory. Analyses were made over a...

This final article on the outlook for U.S. future natural gas supplies expands on the concept of the natural gas resource pyramid. A series of poorly understood but potentially significant emerging gas plays is introduced. These plays reside at various levels within the resource pyramid. These emerging resources include sub-volcanic...

Pre-and post-burn tree mortality rates, size structure, basal area, and ingrowth were determined for four 1.0 ha mixed conifer forest stands in the Log Creek and Tharp's Creek watersheds of Sequoia National Park. Mean annual mortality between 1986 and 1990 was 0.8% for both watersheds. In the fall of 1990,...