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We constructed a model ofpredation by northern squawfish Ptychocheilus oregonensis on juvenile salmonids migrating through John Day Reservoir. The model predicts salmonid survival as a function of number and distribution of northern squawfish, number and timing of juvenile salmonids entering the reservoir, salmonid residence time, water temperature, and flow. The...

A 10-station array (GEOS) yielded recordings of exceptional bandwidth (400 sps) and resolution (up to 96 dB) for the aftershocks of the moderate (mb ≈ 4.9) earthquake that occurred on 31 January 1986 near Painesville, Ohio. Nine aftershocks were recorded with seismic moments ranging between 9 × 1016 and 3 × 1019 dyne-cm...

In the fall of 1986, the Geological Survey of Canada (GSC), the United States Geological Survey (USGS), two Canadian universities -- University of Western Ontario and University of Saskatchewan, and four American universities -- Northern Illinois University, Southern Illinois University, University of Wisconsin-Madison and University of Wisconsin-Oshkosh participated in a...

High-resolution seismic profiles and submersible observations along the leeward slope of western Great Bahama Bank show large-scale export of bank-top sediment and rapid progradation of the slope during the Holocene. A wedge-shaped sequence, up to 90 m thick, is present along most of the slope and consists of predominantly aragonite...

Many Tertiary coals contain abundant fossilized remains of angiosperms, which commonly dominated the ancient peat-swamp environments; modern analogs of such swamps can be found in tropical and subtropical regions of the world. Comparisons of angiospermous wood from Australian brown coal with...

Mammoth Mountain is a 50,000- to 200,000-year-old cumulovolcano standing on the southwestern rim of Long Valley in eastern California. On 4 May 1989, two M = 1 earthquakes beneath the south flank of the mountain marked the onset of a swarm that has continued for more than 6 months. In...

The flattened musk turtle Sternotherus depressus has disappeared from more than half of its former range because of habitat modifications to stream and river channels in the Warrior River Basin, Alabama. Only 6·9% of its probable historic range contains relatively healthy populations, and most populations are fragmented by extensive areas of unsuitable...

Vapor pressures for nonpolar and moderately polar organochlorine, pyrethroid, and organophosphate insecticides, phthalate esters, and organophosphate flame retardants were determined by capillary gas chromatography (GC). Organochlorines and polycyclic aromatic hydrocarbons with known liquid-phase vapor pressures (P??L) (standard compounds) were chromatographed along with two reference compounds n-C20 (elcosane) and p,p???-DDT on...

Out of a number of earlier attempts to explain mass extinctions, only the volcanism alternative to the impact hypothesis remains under serious consideration. The evidence for an impact is reviewed, and the mechanisms which might have brought about the apocalyptic series of extinctions at the Cretaceous-Tertiary (K-T) boundary are reviewed,...

Much has been published about double-diffusive convection as a mechanism for explaining variations in composition and temperature within all-liquid natural systems. However, relatively little is known about the applicability of this phenomenon within the heterogeneous rocks of currently active geothermal systems...

Detailed photoclinometric profiles across 125 erosional features and 141 grabens in the western equatorial region of Mars indicate the presence of three discontinuities within the shallow crust. Pits, troughs, and wall valleys (tributary canyons) within Noctis Labyrinthus and Valles Marineris and escarpments within the fretted terrain of Sacra Fossae and...

Hydrogeologic modeling shows that tabular-type uranium deposits in the Grants uranium region of the San Juan basin, New Mexico, formed in zones of ascending and discharging regional ground-water flow. The association of either lacustrine mudstone or actively subsiding structures and uranium deposits can...

The kinetics of accumulation of pentachlorophenol (PCP) at various pH values were investigated to explore how pH-dependent accumulation might influence PCP toxicity. Goldfish (Carassius auratus) were exposed to 5 μg PCP/L in a static system buffered with 7.5 mM bicine orN,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES) at pH 7.0, 8.0, or 9.0....

A three-dimensional model has been used to estimate the location and dimensions of the eruptive fissure for the 24-29 September 1971 eruption along the southwest rift zone of Kilauea volcano, Hawaii. The model is an inclined rectangular sheet embedded in an elastic half-space with constant displacement on the plane of...

A numerical model was used to evaluate the performance of a surface agitation system designed to contact commercial oxygen with water. The modeled system was unique in that oxygen-rich off-gas, normally discharged to the atmosphere, was directed in serial reuse through additional contact stages receiving untreated water. A correlation between...

A packed column oxygen obsorber was developed in which oxygen flow is directed, in serial reuse, through parallel packed column stages receiving equal portions of the liquid being treated. The relative performance of the absorber was established using a computer simulation program employing finite difference-mass transfer calculations. The program was...

Two simple strategies are presented that use random delay times for repeatedly summing the record of a relatively small earthquake to simulate the effects of a larger earthquake. The simulations do not assume any fault plane geometry or rupture dynamics, but realy only on the ω−2 spectral model of an...

Depositional patterns and sedimentary processes influencing modern southwest Florida carbonate slope development have been identified based upon slope morphology, seismic facies and surface sediment characteristics. Three slope-parallel zones have been identified: (1) an upper slope progradational zone (100–500 m) characterized by...

patially resolved reflectance spectra of Mars in the 2.2- to 2.4-μm spectral region were obtained in August 1988 using the NASA 3-m Infrared Telescope Facility. The spectra show weak absorption features due to Martian atmospheric carbon monoxide and a surface mineral. Both CO and the mineral absorptions are composed of...

Eight Argonne Premium Coal samples and two other coal samples were used to observe the effects of combustion and leaching on 30 elements. The results were used to infer the modes of occurrence of these elements. Instrumental neutron activation analysis indicates that the effects of combustion and leaching on many...

Retention of CO2 on three air-dried and partly water-saturated glacial and eolian sediments was measured at 20°C for a range in, PCO2 that commonly occurs in unsaturated zones. Ratios of the relative losses of CO2 and 14CO2 from a surrogate atmosphere overlying the sediments were 1:1 for the dry condition. For the wet condition, those relative...

Proposals for the formation of a late Wisconsinan ice shelf in the Gulf of Maine during the retreat of the Laurentide Ice Sheet are considered to be inappropriate. An Antarctic-type ice shelf does not fit the field data that indicate temperate glacial, terrestrial, and marine climates for the region between...

The Late Cretaceous Chocolate Mountains thrust of southeastern California and southwestern Arizona places a block of Proterozoic and Mesozoic continental crust over the late Mesozoic continental margin oceanic sedimentary and volcanic rocks of the regionally distinctive Orocopia Schist. The Chocolate Mountains thrust is interpreted as a thrust (burial, subduction) fault...

Horizontal ground deformation measurements were made repeatedly with an electronic distance meter near the Puu Oo eruption site approximately perpendicular to Kilauea's east rift zone (ERZ) before and after eruptive episodes 22-42. Line lengths gradually extended during repose periods and rapidly contracted about the same amount following eruptions. The repeated...

There were no major earthquakes during the first 2 months of the year and there were no earthquake-related deaths reported during this same time period. In the United States a moderate earthquake on February 28 in southern California caused some minor injuries and considerable damage. ...