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Ace of diamonds: Cyclohexamantane (C26H30), a large diamond-like molecule containing six peri-fused adamantane cages was identified in petroleum and its structure proven by X-ray crystallography (see picture), Never synthesized because of severe mechanistic difficulties, the structure of cyclohexamantane has appeared in theoretical molecular-simulation studies related to diamond; its experimentally determined...

Seafloor mapping of shelf-edge habitats in the northeastern Gulf of Mexico demonstrates how sidescan-sonar imagery, seismic-reflection profiling, video data, geologic mapping, sediment sampling, and understanding the regional geologic history can enhance, support, and guide traditional fisheries research and management. New data from the Madison Swanson and Steamboat Lumps Marine Reserves...

To fully understand the hydraulic properties of natural rivers, velocity distribution in the river cross-section should be studied in detail. The measurement task is not straightforward because there is not an instrument that can measure the velocity distribution covering the entire cross-section. Particularly, the velocities in regions near the free...

Hurricane Floyd in September 1999 caused disastrous flooding from South Carolina to Massachusetts in the United States, with particularly severe and prolonged flooding in eastern North Carolina resulting in record flood-flow loadings of freshwater and contaminants to Pamlico Sound, North Carolina. The inland flooding, water quality, and loadings to Pamlico...

Hankin and Reeves' (1988) approach to estimating fish abundance in small streams has been applied in stream fish studies across North America. However, their population estimator relies on two key assumptions: (1) removal estimates are equal to the true numbers of fish, and (2) removal estimates are highly correlated with...

The Land-Ocean Interactions in the Coastal Zone Project of the International Geosphere-Biosphere Programme focused on quantifying the role of the global coastal zone in the cycling of carbon and nutrients. From 1993 to date, it has developed protocols and tools that allow for site-specific and global assessments of coastal processes...

Geomorphologists have long recognized that eolian sand transport pathways extend over long distances in desert regions. Along such pathways, sediment transport by wind can surmount topographic obstacles and cross major drainages. Recent studies have suggested that three distinct eolian sand transport pathways exist (or once existed) in the Mojave and...

Wattenberg field is a continuous-type gas accumulation. Estimated ultimate recovery from current wells is 1.27 tcf of gas from the Lower Cretaceous Muddy (J) Sandstone. Mean gas resources that have the potential to be added to these reserves in the next 30 yr...

Development of effective conservation plans for terrestrial animals will require some assessment of which human-modified and natural habitats can support populations of priority species. We examined bird communities associated with 11 natural and human-modified habitats in Panama and assessed the importance of those habitats for species of different vulnerability to...

Aim: This paper aims at determining how different floristic elements (e.g. cosmopolitan, tropical, and temperate) change with latitude and major climate factors, and how latitude affects the floristic relationships between East Asia and the other parts of the world. Location: East Asia from the Arctic to tropical regions, an area...

Vernal pools on the High Lava Plain of the northern Great Basin become ponded in most years, but their soils exhibit weak redoximorphic features indicative of hydric conditions. We studied the hydrology, temperature, redox potentials, soil chemistry, and soil morphology of a vernal pool to determine if the soils are...

No abstract available....

We present phase velocity maps of fundamental mode Rayleigh waves across the North American and Caribbean plates. Our data set consists of 1846 waveforms from 172 events recorded at 91 broad-band stations operating in North America. We compute phase velocity maps in four narrow period bands between 50 and 150...

Data collected from 20 major river basins between 1993 and 1995 as part of the US Geological Survey's (USGS) National Water-Quality Assessment (NAWQA) Program were analyzed to assess patterns in introduced and native fish species richness and abundance relative to watershed characteristics and stream physicochemistry. Sites (N = 157) were...

The water chemistry of a groundwater-fed sinkhole-pond near St. Louis, Missouri, and its associated climate during the last glaciation are reconstructed by comparison with autecological data of modern ostracodes from about 5,500 sites in Canada. A 4.8-m succession of fossiliferous sediment yielded ostracode assemblages that collectively are generally found today...

In Illinois, atmospheric deposition is one major source of heavy metal inputs to agricultural land. The atmospheric Pb deposition and transport record in agricultural soils in Champaign, Illinois, was established by studying surface and subsurface soil samples collected during the past 100 years from the Morrow Plots on the campus...

We have determined the extent of Se isotope fractionation induced by reduction of selenate by sulfate interlayered green rust (GRSO4), a Fe(II)-Fe(III) hydroxide-sulfate. This compound is known to reduce selenate to Se(0), and it is the only naturally relevant abiotic selenate reduction pathway...

In a growing body of literature from a variety of ecosystems is strong evidence that various components of biodiversity have significant impacts on ecosystem functioning. However, much of this evidence comes from short-term, small-scale experiments in which communities are synthesized from relatively small species pools and conditions are highly controlled....

Broadband seismic data collected on Ruapehu volcano, New Zealand, in 1994 and 1998 show that the 1995-1996 eruptions of Ruapehu resulted in a significant change in the frequency content of tremor and volcanic earthquakes at the volcano. The pre-eruption volcanic seismicity was characterized by several independent dominant frequencies, with a...

The Total Maximum Daily Load (TMDL) for ammonia and biochemical oxygen demand for the Pee Dee, Waccamaw, and Atlantic Intracoastal Waterway system near Myrtle Beach, South Carolina, mandated a 60-percent reduction in point-source loading. For waters with a naturally low background dissolved-oxygen concentrations, South Carolina anti-degradation rules in the water-quality...

The deep crustal rocks exposed in the Ruby-East Humboldt metamorphic core complex, northeastern Nevada, provide a guide for reconstructing Eocene crustal structure ∼50 km to the west near the Carlin trend of gold deposits. The deep crustal rocks, in the footwall of a west-dipping normal-sense shear system, may have underlain the Piñon and Adobe Ranges about 50 km to the west before Tertiary extension, close to or under part of the Carlin trend. Eocene lakes formed on the hanging wall of the fault...

Observations of density and velocity in a channel in northern San Francisco Bay show that the onset of vertical density stratification during flood tides is controlled by the balance between the cross-channel baroclinic pressure gradient and vertical mixing due to turbulence. Profiles of velocity, salinity, temperature, and suspended sediment concentration...

Environmental pollutants are hypothesized to be one of the causes of recent declines in wild populations of Atlantic salmon (Salmo salar) across Eastern Canada and the United States. Some of these pollutants, such as polychlorinated biphenyls and dioxins, are known to induce expression of the CYP1A subfamily of genes. We...

Longshore sediment transport rates were estimated on a microtidal estuarine beach in Great South Bay, N.Y., during two dyed sand tracer experiments using a temporal sampling method. Mean onshore wind speeds of 5.8 and 9.9 m/s resulted in root-mean-square wave heights of 0.07 and 0.08 m and wave angles of...