bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Equatorial Ocean Currents by Turbulent Dissipation
Authors: Crawford William R. , Osborn Thomas R.
Published: October 2006

The importance of turbulence in the flow of equatorial currents has been noted by modelers but not observed. Recent measurements of turbulence show an increase in strength at the equator and confirm its role as a sink of the kinetic energy of currents at the equator.
Visual and "Phonetic" Coding of Movement: Evidence from American Sign Language
Authors: Poizner Howard
Published: October 2006

Hearing subjects unfamiliar with American Sign Language and deaf native signers made triadic comparisons of movements of the hands and arms isolated from American Sign Language. Clustering and scaling of subjects' judgments revealed different psychological representations of movement form for deaf and hearing observers. Linguistically relevant dimensions acquired modified salience for users of a visual-gestural language. The data indicate that the modification of natural perceptual categories after language acquisition is not bound to a particular transmission modality, but rather can be a more general consequence of acquiring a formal linguistic system.
Todorokites: A New Family of Naturally Occurring Manganese Oxides
Authors: Turner Shirley , Buseck Peter R.
Published: October 2006

Todorokites are found in numerous terrestrial deposits and are important copper- and nickel-bearing materials in manganese nodules. Their structures are highly disordered, not well known, and controversial. High-resolution transmission electron microscopy reveals that terrestrial todorokites consist of tunnel structures of previously unreported dimensions and that these tunnel structures are intergrown coherently on a unit cell scale. Many types and degrees of disorder are evident in the high-resolution images. These newly discovered structures indicate a need for a revised nomenclature of tunnel manganese oxides, and such a system is suggested.
Light Modulates Voltage-Dependent Potassium Channels in
Limulus
Ventral Photoreceptors
Authors: Leonard Reid J. , Lisman John E.
Published: October 2006

Voltage-dependent outward current measured in the dark is reduced after illumination. This reduction can be blocked by tetraethylammonium and is associated with a decrease in total membrane conductance. The voltage dependence of the current reduced by light is the same as that of the delayed rectifier. These results indicate that light modulates the delayed rectifier. This modulation serves to maintain a stable voltage response to constant illumination.
Allocating Petroleum Products During Oil Supply Disruptions
Authors: Bezdek Roger H. , Taylor William B.
Published: October 2006

Four options for allocating a long-term, severe shortfall of petroleum imports are analyzed: oil price and allocation controls, coupon gasoline rationing, variable gasoline tax and rebate, and no oil price controls with partial rebates. Each of these options is evaluated in terms of four criteria: microeconomic effects, macroeconomic effects, equity, and practical problems. The implications of this analysis for energy contingency planning are discussed.
1979J3: Discovery of a Previously Unknown Satellite of Jupiter
Authors: SYNNOTT S. P.
Published: October 2006

During a detailed search of Voyager 1 frames for additional observations of the satellite 1979J1, two small dark spots were observed in transit in several consecutive wide-angle frames of the Jovian atmosphere. The size, spacing, and motion of these pairs of dark spots indicated that they were the images of 1979J1 and its shadow. Subsequent analysis of images spanning 6 days, however, proved that the satellite observed in these Voyager 1 frames would have been occulted by Jupiter at the times of the Voyager 2 images of 1979J1 and was, therefore, a new satellite. It was subsequently found in transit on Voyager 2 images within 13° of the Voyager 1 prediction. Its period is 7 hours 4 minutes 30 seconds ± 3 seconds, and its mean distance is 1.793 Jupiter radii (Jupiter radius = 71,400 kilometers). The observable profile appears to be roughly circular with a diameter of 40 kilometers, and the albedo is ∼0.05, similar to Amalthea's.
Control of Calcium Carbonate Nucleation and Crystal Growth by Soluble Matrx of Oyster Shell
Authors: Wheeler A. P. , George James W. , Evans C. A.
Published: October 2006

A calcium-binding soluble protein extracted from oyster shell suppresses calcium carbonate nucleation and decreases the rate of crystal growth in vitro. These findings suggest that soluble matrix may regulate shell growth.
Bacterial Origin of a Chloroplast Intron: Conserved Self-Splicing Group I Introns in Cyanobacteria
Authors: Xu Ming-Qun , Kathe Scott D. , Goodrich-Blair Heidi , Nierzwicki-Bauer Sandra A. , Shub David A.
Published: October 2006

A self-splicing group I intron has been found in the gene for a leucine transfer RNA in two species of
Anabaena
, a filamentous nitrogen-fixing cyanobacterium. The intron is similar to one that is found at the identical position in the same transfer RNA gene of chloroplasts of land plants. Because cyanobacteria were the progenitors of chloroplasts, it is likely that group I introns predated the endosymbiotic association of these eubacteria with eukaryotic cells.
Geodynamics—Where Are We and What Lies Ahead?
Authors: Drake Charles L. , Maxwell John C.
Published: October 2006

The introduction and evolution of the plate tectonics hypothesis during the past two decades has sparked the current renaissance of research in the earth sciences. An outgrowth of active geophysical and geological exploration of the oceans, the plate tectonics model has come under intense scrutiny by geologists, geochemists, and geophysicists who have attempted to apply the model to the origin and growth of continents, the generation of oceanic and continental crust, and the nature of the lithosphere, asthenosphere, and underlying mantle with respect to their evolution through time and to the driving mechanism or mechanisms for plate tectonics. The study of other terrestrial planets and moons has been helpful in understanding the earth model. The unequal distribution of geological features, both in the continents and oceans, emphasizes the need for ongoing studies of international scope such as the recently completed International Geodynamics Project and its successor, the International Lithosphere Program, both stressing studies related to the dynamics of the lithosphere.
Hotspots, Basalts, and the Evolution of the Mantle
Authors: Anderson Don L.
Published: October 2006

The trace element concentration patterns of continental and ocean island basalts and of mid-ocean ridge basalts are complementary. The relative sizes of the source regions for these fundamentally different basalt types can be estimated from the trace element enrichment-depletion patterns. Their combined volume occupies most of the mantle above the 670 kilometer discontinuity. The source regions separated as a result of early mantle differentiation and crystal fractionation from the resulting melt. The mid-ocean ridge basalts source evolved from an eclogite cumulate that lost its late-stage enriched fluids at various times to the shallower mantle and continental crust. The mid-ocean ridge basalts source is rich in garnet and clinopyroxene, whereas the continental and ocean island basalt source is a garnet peridotite that has experienced secondary enrichment. These relationships are consistent with the evolution of a terrestrial magma ocean.
Tropical Archeoastronomy
Authors: Aveni A. F.
Published: October 2006

Too often, judged by the Western cultural yardstick, astronomical systems developed by indigenous civilizations of the tropical latitudes are found to be both complex and fundamentally different from those originating in civilizations of the temperate latitudes. One explanation for this difference is the radically contrasting sky orientations that are viewed from different parts of the globe, a determinative environmental factor in the development of cosmological systems that should not be neglected by the anthropologist and cultural historian.
Generation of Stabilized Microbubbles in Seawater
Authors: Johnson Bruce D. , Cooke Robert C.
Published: October 2006

Bubbles of less than 1 micrometer and as large as 13.5 micrometers in diameter, stabilized by an apparent compression of substances sorbed onto their surfaces, were examined to determine their physical and temporal stability. Their ease of formation is related to the qualities of the water in which they are formed. Their presence in the water column must now be considered when interpreting acoustic data gathered to determine marine bubble populations.
Holocene Sea-Level Curves for Santa Monica Shelf, California Continental Borderland
Authors: Nardin Thomas R. , Osborne Robert H. , Bottjer David J. , Scheidemann Robert C.
Published: October 2006

A curve is constructed showing changes in sea level at the Santa Monica shelf over the past 18,000 years. The curve is based on radiocarbon dates, sedimentologic data, and high-resolution seismic stratigraphic analysis of late Quaternary terrace deposits. Sea level was 117 meters below its present position about 18,000 years ago. During the first 8000 years of the Flandrian transgression, sea level rose to at least 24 meters, fell to about 46 meters, and then rose to 20 meters, all below present sea level. Subsequently, sea level rose more slowly and without discernible interruption to its present position.
Size of the Chloroplast Genome in
Codium fragile
Authors: Hedberg Mary F. , Huang Yuan-Shen , Hommersand Max H.
Published: October 2006

Chloroplasts isolated from the siphonous green alga
Codium
fragile yield circular DNA molecules averaging 27.3 micrometers in length and 56 × 10
6
daltons in molecular size. This chloroplast genome is 25 to 30 percent smaller than any reported. The small size of the
Codium
chloroplast genome may represent a primitive evolutionary condition in green plants.
Lapita Colonization of the Admiralty Islands?
Authors: Kennedy Jean
Published: October 2006

Archeological research in the Admiralty Islands provides evidence of occupation by 3500 years ago and suggests settlement by obsidian-using maritime colonists, whose Lapita pottery style underwent gradual modification within the Admiralties.
Size and Age of the Universe
Authors: van den Bergh Sidney
Published: October 2006

The age of the universe based on abundances of isotopes is in the range 10 billion to 15 billion years. This is consistent with the age range 12 billion to 20 billion years calculated from the evolution of the oldest galactic stars. A third estimate of the age of the universe is based on the Hubble relation between the velocities of galaxies and their distances from us, where the inverse of the Hubble parameter
H
is a measure of the age of a uniformly expanding universe. Evidence that has been accumulating over the past few years indicates that the expansion of the universe may exhibit a rather large local perturbation due to the gravitational attraction of the Virgo supercluster. Different types of observations still produce conflicting evidence about the velocity with which the Local Group of galaxies (of which our Milky Way system is a member) is falling into the Virgo cluster. The results to date indicate that this velocity lies somewhere in the range 0 to 500 kilometers per second. The resulting ambiguity in the flow pattern for relatively nearby galaxies makes values of
H
derived from galaxies with radial velocities less than 2000 kilometers per second particularly uncertain, and this restricts determinations of
H
to distant galaxies, for which distances are particularly uncertain. The best that can be said at present is that
H
–1
yields a maximum time scale in the range 10 billion to 20 billion years.
Competition for Dispersal in Ant-Dispersed Plants
Authors: Davidson D. W. , Morton S. R.
Published: October 2006

Two closely related and coexisting plants (Chenopodiaceae) of the Australian arid zone are adapted for seed dispersal by ants. These facultatively perennial shrubs persist in saltbush communities largely as a result of highly directional dispersal to ant mounds, where conditions are favorable for establishment and growth. The two species grow predominantly on mounds and compete for dispersal to these favorable microhabitats.
Monsoon Climate of the Early Holocene: Climate Experiment with the Earth's Orbital Parameters for 9000 Years Ago
Authors: Kutzbach John E.
Published: October 2006

Values for the precession and obliquity of the earth 9000 years ago indicate that the global average solar radiation for July 9000 years ago was 7 percent greater than at present. When the estimated solar radiation values are used in a low-resolution climate model, the model simulates an intensified continent-scale monsoon circulation. This result agrees with paleoclimatic evidence from Africa, Arabia, and India that monsoon rains were stronger between 10,000 and 5000 years ago than they are today.
The Spectroscopy of Very Cold Gases
Authors: Levy Donald H.
Published: October 2006

The technique of supersonic free jet spectroscopy can be used to study the structure and dynamics of molecules which have been cooled to far below their boiling points but which remain in the gas phase. Cooling of the internal degrees of freedom, the molecular rotations and vibrations, produces a highly resolved and greatly simplified molecular spectrum. The principles of the technique are discussed and its utility is demonstrated by two examples: the spectroscopy of porphyrins in the gas phase and the photochemistry of van der Waals molecules.
New Approaches to Surface Structure Determinations
Authors: Eisenberger P. , Feldman L. C.
Published: October 2006

Progress in understanding the many scientifically interesting and technologically important processes that occur at surfaces has been slowed by the absence of basic structural information. A variety of new techniques are being developed to attack this central problem in surface science. With the new surface probes it is now possible to quantitatively determine the arrangement of atoms in the first monolayers of a solid. This provides the basis for exciting advances in surface science.
Summer Ice and Carbon Dioxide
Authors: Kukla G. , Gavin J.
Published: October 2006

The extent of Antarctic pack ice in the summer, as charted from satellite imagery, decreased by 2.5 million square kilometers between 1973 and 1980. The U.S. Navy and Russian atlases and whaling and research ship reports from the 1930's indicate that summer ice conditions earlier in this century were heavier than the current average. Surface air temperatures along the seasonally shifting belt of melting snow between 55° and 80°N during spring and summer were higher in 1974 to 1978 than in 1934 to 1938. The observed departures in the two hemispheres qualitatively agree with the predicted impact of an increase in atmospheric carbon dioxide. However, since it is not known to, what extent the changes in snow and ice cover and in temperature can be explained by the natural variability of the climate system or by other processes unrelated to carbon dioxide, a cause-and-effect relation cannot yet be established.
Salt Diapirs Bordering the Continental Margin of Northern Kenya and Southern Somalia
Authors: Rabinowitz Philip D. , Coffin Millard F. , Falvey David
Published: October 2006

The presence of newly discovered diapirs of presumed salt origin is documented for the continental margin of northeastern Kenya and southeastern Somalia. These structures are probably a manifestation of a significant thickness of Lower Jurassic evaporites deposited during the rift and early-drift stages of the separation of Madagascar from the African continent.
Office Automation
Authors: Spinrad R. J.
Published: October 2006

The automated office has the potential to change significantly the ways we handle the substance of our working lives. Advances in electronics and computer systems enable us to do much more than just upgrade individual office functions. We can now restructure our basic information handling modes to allow an immediacy of interaction not previously available. The tedium of paperwork is sharply reduced and it becomes much easier to work collaboratively with others. The electronic desk becomes the professional's link to a widely distributed array of information sources and services.
Evolution of the Intelligent Telecommunications Network
Authors: Mayo John S.
Published: October 2006

A stream of new technologies has transformed the nationwide telecommunications network into the world's largest and most sophisticated information handling system. Computers and software have made the network "intelligent" and allow it to be programmed with great flexibility to bring a myriad of new services to homes and offices.
Migration of Ruthenium-106 in a Nevada Test Site Aquifer: Discrepancy Between Field and Laboratory Results
Authors: Coles David G. , Ramspott Lawrence D.
Published: October 2006

Ruthenium-106 has been observed to migrate in ground water at about the same velocity as tritium from the site of an underground nuclear explosion to a pumped satellite well 91 meters distant. This finding contradicts the prediction, based on laboratory batch sorption measurements, that ruthenium-106 should migrate at a much lower rate than tritium. To predict migration of radionuclides in ground water, more relevant laboratory measurements are required.
Atmospheric Deposition of Metals to Forest Vegetation
Authors: Lindberg Steven E. , Harriss Robert C. , Turner Ralph R.
Published: October 2006

Atmospheric deposition during the growing season contributes one-third or more of the estimated total flux of lead, zinc, and cadium from the forest canopy to soils beneath an oak stand in the Tennessee Valley but less than 10 percent of the flux of manganese. The ratio of the wet to dry deposition flux to the vegetation during this period ranges from 0.1 for manganese to 0.8 for lead to ∼ 3 to 4 for cadmium and zinc. Interactions between metal particles deposited on dry leaf surfaces and subsequent acid precipitation can result in metal concentrations on leaves that are considerably higher than those in rain alone.
NMR Characterization of Surface Interactions in the Cytochrome b
5
-Cytochrome c Complex
Authors: Burch Anita M. , Rigby Stephen E. J. , Funk Walter D. , MacGillivray Ross T. A. , Mauk Marcia R. , Mauk A. Grant , Moore Geoffrey R.
Published: October 2006

The complex formed in solution by native and chemically modified cytochrome c with cytochrome b
5
has been studied by
1
H and
13
C nuclear magnetic resonance spectroscopy (NMR). Contrary to predictions of recent theoretical analysis,
1
H NMR spectroscopy indicates that there is no major movement of cytochrome c residue Phe
82
on binding to cytochrome b
5
. The greater resolution provided by
13
C NMR spectroscopy permits detection of small perturbations in the environments of cytochrome c residues Ile
75
and Ile
85
on binding with cytochrome b
5
, a result that is in agreement with earlier model-building experiments. As individual cytochrome c lysyl residues are resolved in the
1
H NMR spectrum of
N
-acetimidylated cytochrome c, the interaction of this modified protein with cytochrome b
5
has been studied to evaluate the number of cytochrome c lysyl residues involved in binding to cytochrome b
5
. The results of this experiment indicate that at least six lysyl residues are involved, two more than predicted by static model building, which indicates that cytochrome c and cytochrome b
5
form two or more structurally similar 1:1 complexes in solution.
Biological Responses of Lakes in the Mount St. Helens Blast Zone
Authors: Wissmar Robert C. , Devol Allen H. , Staley James T. , Sedell James R.
Published: October 2006

Loadings of dissolved organics and suspended particulates from destroyed forests and volcanic debris produced by the 18 May 1980 eruption of Mount St. Helens altered the trophic structure of many blast zone lakes to the extent that anoxic conditions and chemoorganotrophic and chemolithotrophic microorganisms prevailed. High bacterial counts and high adenosine triphosphate concentrations were directly related to enhanced concentrations of dissolved organic carbon, and plankton chlorophyll a was inversely related to light extinction. The recovery of these lakes to the preeruption state appears dependent upon the oxidation of organics and the stabilization of watersheds.
The Most Distant Known Galaxies
Authors: Kron Richard G.
Published: October 2006

Ever since the proposal of the idea of an expanding universe more than 50 years ago, each generation of investigators has found that some current theory could be (marginally) tested by the properties of the most distant known galaxies. There has consequently been a continuing effort to identify very remote objects, especially to confront theories of the evolution of galaxies (since galaxies are seen as they were at prior epochs) and to confront cosmological theories (which make predictions about the overall dynamics of the expansion of the universe). These theories have yet to be definitively tested, but a new generation of optical telescopes and detectors provides hope for significant progress during this decade.
Rediscovery of the Yellow-Fronted Gardener Bowerbird
Authors: Diamond Jared M.
Published: October 2006

The long-lost bowerbird
Amblyornis flavifrons
was found in the Foja Mountains of west New Guinea, and its bower and display were discovered. The bower is a stick tower on a rimmed moss platform, adorned with separate piles of fruit of three different colors. The displaying male extends toward the female a blue fruit set against his golden crest. These observations support a derivation of bower ornamentation from ritual courtship feeding and a transfer of ornamentation from the male's plumage to the bower.
Radionuclides in Mono Lake, California
Authors: Simpson H. J. , Trier R. M. , Toggweiler J. R. , Mathieu G. , Deck B. L. , Olsen C. R. , Hammond D. E. , Fuller C. , Ku T. L.
Published: October 2006

Several radioisotopes of the naturally occurring uranium and thorium decay series, in addition to fallout plutonium, have unusually high concentrations in the water column of Mono Lake, a natural alkaline, saline lake. Complexing by carbonate ions appears to be responsible for the enhanced solubility of actinide elements with oxidation states of IV to VI. In contrast, fallout strontium-90 has been largely removed from the water, probably as a result of coprecipitation with calcium carbonate. The daughter/parent activity ratios of thorium, radium, and uranium isotopes suggest that thorium is removed from the water column to the sediments on time scales substantially longer than a month and that the desorption of thorium from the sediments to the water column requires less than a few years.
Elevated Concentrations of Actinides in Mono Lake
Authors: Anderson R. F. , Bacon M. P. , Brewer P. G.
Published: October 2006

Tetravalent thorium, pentavalent protactinium, hexavalent uranium, and plutonium (oxidation state uncertain) are present in much higher concentrations in Mono Lake, a saline, alkaline lake in eastern central California, than in seawater. Low ratios of actinium to protactinium and of americium to plutonium indicate that the concentrations of trivalent actinides are not similarly enhanced. The elevated concentrations of the ordinarily very insoluble actinides are maintained in solution by natural ligands, which inhibit their chemical removal from the water column, rather than by an unusually large rate of supply.
Current Speed and Filtration Rate Link Caddisfly Phylogeny and Distributional Patterns on a Stream Gradient
Authors: Alstad D. N.
Published: October 2006

Patterns of body size and net construction suggest that current speed and food-particle concentration (not size) influence the distribution of suspension-feeding caddisflies on a downstream gradient. Large ancestral taxa with high filtration rates occur in resource-poor upstream habitats; more derived members of the phylogeny enter successively in downstream reaches with slower current and greater concentrations of particulate food.
Geochronology of Type Uquian (Late Cenozoic) Land Mammal Age, Argentina
Authors: Marshall Larry G. , Butler Robert F. , Drake Robert E. , Curtis Garniss H.
Published: October 2006

Mammal faunas collected from the Uquía Formation at Chucalezna and Esquina Blanca in Jujuy Province, northwest Argentina, are calibrated by potassium-argon age determinations and paleomagnetic polarity data. The sediments range in age from 2.5 million years old to perhaps as young as 1.5 million years, from late Pliocene through early Pleistocene, and correspond in time to late Blancan and early Irvingtonian land mammal age faunas in North America.
Deep Oxygenated Ground Water: Anomaly or Common Occurrence?
Authors: Winograd Isaac J. , Robertson Frederick N.
Published: October 2006

Contrary to the prevailing notion that oxygen-depleting reactions in the soil zone and in the aquifer rapidly reduce the dissolved oxygen content of recharge water to detection limits, 2 to 8 milligrams per liter of dissolved oxygen is present in water from a variety of deep (100 to 1000 meters) aquifers in Nevada, Arizona, and the hot springs of the folded Appalachians and Arkansas. Most of the waters sampled are several thousand to more than 10,000 years old, and some are 80 kilometers from their point of recharge.
Compositional Structure of the Asteroid Belt
Authors: Gradie J. , Tedesco E.
Published: October 2006

The distribution of compositional types among the asteroids is found to vary systematically with heliocentric distance. Seven distinct peaks in the relative proportion of the compositional types E, R, S, M, F, C, P, and D are found from 1.8 to 5.2 astronomical units. The inferred composition of the asteroids in each semimajor axis region is consistent with the theory that the asteroids accreted from the solar nebula at or near their present locations.
York River Destratification: An Estuary-Subestuary Interaction
Authors: Hayward Don , Welch Christopher S. , Haas Leonard W.
Published: October 2006

Destratification in the York River during high spring tides is the result of the interruption of normal two-layer estuarine flow by the advection of relatively fresh water into the river mouth from the Chesapeake Bay. This advection is due to the presence of a longitudinal salinity gradient in the bay and a difference in the tidal current phase between the river and the bay. Similar behavior is seen in other subestuaries of the Chesapeake Bay and may be common in subestuary-estuary interactions.
Status of the Development of EDS Coal Liquefaction
Authors: Vick G. K. , Epperly W. R.
Published: October 2006

This article traces the evolution and development of a modern coal liquefaction technology, the EDS (Exxon Donor Solvent) process, over a period of 15 years. During this time the technology has been advanced from laboratory experiments to a pilot plant with a coal feed rate of 250 tons per day, and findings from several areas of science and technology have been important. The process is now in the final stage of development to generate the data needed to design a plant of commercial size.
Outlook for Soviet Oil
Authors: Scanlan Tony
Published: October 2006

Public debate about Soviet oil has become more widespread in the past 5 years, but during this period Soviet petroleum exports have ceased to be made available by volume. Soviet oil consumption has usually been estimated by deducting exports from total production. This article takes the alternative approach, using Soviet statistics from a variety of sources, to build up a sectoral pattern of Soviet oil demand and to consider this in the broader context of total Comecon energy supply and demand. From this focus future prospects for the Comecon energy balance are analyzed.
The Ediacarian Period and System: Metazoa Inherit the Earth
Authors: Cloud Preston , Glaessner Martin F.
Published: October 2006

The Ediacarian, here defined as the initial period and system of the Phanerozoic Eon, is characterized by the oldest known multicellular animal life. The distinctive biotal assemblage comprises naked Metazoa, represented in the type region by 26 species in 18 genera and 4 or more phyla, plus simple metazoan surface tracks. Elements of this unique biota appeared worldwide at low paleolatitudes, following terminal Proterozoic glaciation. Ediacarian history lasted from about 670 million to 550 million years ago. This interval, plus Early Cambrian, was the time during which metazoan life diversified into nearly all of the major phyla and most of the invertebrate classes and orders subsequently known.
Organic Matter in a Coal Ball: Peat or Coal?
Authors: Hatcher Patrick G. , Lyons Paul C. , Thompson Carolyn L. , Brown Floyd W. , Maciel Gary E.
Published: October 2006

Chemical analyses of morphologically preserved organic matter in a Carboniferous coal ball reveal that the material is coalified to a rank approximately equal to that of the surrounding coal. Hence, the plant tissues in the coal ball were chemically altered by coalification processes and were not preserved as peat.
Solutions to Environmental and Economic Problems (STEEP)
Authors: Oldenstadt Dennis L. , Allan Robert E. , Bruehl George W. , Dillman Donald A. , Michalson Edgar L. , Papendick Robert I. , Rydrych Donald J.
Published: October 2006

This article describes one model for organizing and mobilizing scientific resources to address the highly complex and costly problem of soil erosion in the Pacific Northwest. With a U.S. Department of Agriculture grant to the agricultural experiment stations in Washington, Oregon, and Idaho, as well as supplementary state and federal funds, STEEP awards intermediate-term (15 year) grants for research in five areas: tillage and plant management, plant design, erosion and runoff predictions, pest management, and socioeconomics of erosion control. Most of the research projects require collaboration across disciplines and, in some instances, across state boundaries. After 6 years of effort the results obtained with STEEP indicate that the model might be applicable to other regions and problems.
Characteristics of the Ionization Tracks and Interactions of Uranium-238 Nuclei in Emulsion
Authors: Heckman H. H. , Karant Y. J. , Friedlander E. M.
Published: October 2006

The acceleration and extraction of uranium-238 nuclei by the Bevalac have been confirmed by their visual detection in nuclear research emulsion. A preliminary result for the collision mean free path for stopping uranium-238 (energy ≤ 115 million electron volts per nucleon) is 3.1 ± 0.6 centimeters. Qualitative characteristics of the observed uranium-nucleus collisions are also described.
Nitrogen Fixation in the Marine Environment
Authors: Capone Douglas G. , Carpenter Edward J.
Published: October 2006

Cyanobacteria of the genus
Oscillatoria
(
Trichodesmium
) account for annual inputs of nitrogen to the world's oceans of about 4.8 × 10
12
grams while benthic environments contribute 15 × 10
12
grams. The sum of these inputs is one-fifth of current estimates of nitrogen fixation in terrestrial environments and one-half of the present rate of industrial synthesis of ammonia. When the total of all nitrogen inputs to the sea is compared with estimated losses through denitrification, the marine nitrogen cycle approximates a steady state. Oceanic nitrogen fixation can supply less than 0.3 percent of the calculated demand of marine phytoplankton. The minor contribution by nitrogen fixation to the overall nitrogen economy of the sea is not consistent with the supposition that nitrogen is the primary limiting nutrient and suggests that factors other than nitrogen availability limit phytoplankton growth rates.
Nitrogen Source for a Detritivore: Detritus Substrate Versus Associated Microbes
Authors: Findlay Stuart , Tenore Ken
Published: October 2006

Detritivores have been thought to derive nutrition from microbes associated with detrital particles and not from the nonliving plant substrate. The polychaete
Capitella capitata
, however, was found to derive a major portion of its nitrogen from the plant substrate when it feeds on detritus derived from seaweed. Microbes play a role as a nitrogen source for this detritivore when it feeds on detritus derived from marsh grass.
Longevity of Guard Cell Chloroplasts in Falling Leaves: Implication for Stomatal Function and Cellular Aging
Authors: Zeiger Eduardo , Schwartz Amnon
Published: October 2006

Guard cell chloroplasts in senescing leaves from 12 species of perennial trees and three species of annual plants survived considerably longer than their mesophyll counterparts. In
Ginkgo biloba
, stomata from yellow leaves opened during the day and closed at night; guard cell chloroplasts from these leaves showed fluorescence transients associated with electron transport and photophosphorylation. These findings indicate that guard cell chloroplasts are highly conserved throughout the life-span of the leaf and that leaves retain stomatal control during senescence.
Discovery of a Large-Magnitude, Late Pleistocene Volcanic Eruption in Alaska
Authors: Westgate John A.
Published: October 2006

An extensive blanket of dacitic tephra was deposited across Alaska and the western Yukon Territory by a plinian eruption about 80,000 years ago. The volume of tephra erupted probably exceeded 50 cubic kilometers and the source was probably in the Wrangell Mountains. This widespread layer of tephra serves as an excellent late Pleistocene stratigraphic marker.
Lesion-Induced Sprouting in the Rat Dentate Gyrus Is Inhibited by Repeated Ethanol Administration
Authors: West James R. , Lind Marcia D. , Demuth Ronald M. , Parker Elizabeth S. , Alkana Ronald L. , Cassell Martin , Black Asa C.
Published: October 2006

The effect of ethanol on hippocampal axonal sprouting was studied with a histochemical technique for identifying acetylcholinesterase. Unilateral lesion of the entorhinal cortex in adult rats produced an increase in the density of acetylcholinesterase staining in the outer molecular layer and a concomitant increase in the width of the pale-staining commissural-associational zone of the dentate gyrus. Other rats were given ethanol (11.3 ± 0.45 grams per kilogram) for 2 weeks before and 9 days after receiving the lesion. Ethanol abolished the expansion of the commissural-associational zone. The effect of ethanol on sprouting axons suggests that it may inhibit recovery of function after brain injury.
German Energy Technology Prospects
Authors: Popp Manfred
Published: October 2006

After more than 25 years of development of nuclear power and almost 10 years of research and development in numerous areas of nonnuclear energy, there is now a good basis for judging the future prospects of energy technologies in the Federal Republic of Germany. The development of nuclear power has provided an important and economically advantageous new source of energy. Further efforts are needed to establish the nuclear fuel cycle in all stages and to exploit the potential of advanced reactors. In all other areas of energy technology, including energy conservation, new energy sources, and coal, economics has turned out to be the key problem, even at today's energy prices. Opportunities to overcome these economic problems through additional R & D are limited. There is some potential for special applications, and there are many technologies that could contribute to the energy supply of developing countries. In general, however, progress in energy conservation and the use of renewable energy sources will depend on the degree to which energy policy measures can improve their economic basis. For some technologies, such as solar thermal power stations and coal liquefaction, large-scale economic deployment cannot be foreseen today. Instead of establishing costly demonstration projects, emphasis will be put on improving key components of these technologies with the aim of having the most advanced technology available when the economic parameters are more favorable.
Selectivity: A Key to Synthetic Efficiency
Authors: Trost Barry M.
Published: October 2006

The efficient synthesis of organic compounds requires the development of processes with enhanced selectivity. Selectivity is categorized according to chemical reactivity (chemoselectivity), orientation (regioselectivity), and spatial arrangement (diastereoselectivity and enantioselectivity). Recent developments in reduction-oxidation methods and C—C bond forming reactions illustrate some solutions to problems of selectivity. The design of selectivity-inducing groups and the increased role of main group and transition metals in enhancing selectivity are especially noted.
Contributions of Conventional Plant Breeding to Food Production
Authors: Borlaug Norman E.
Published: October 2006

Within a relatively short geological time frame, Neolithic man, or more probably woman, domesticated all the major cereal grains, legumes, and root crops that the world's people depend on for most of their calories and protein. Until very recently, crop improvement was in the hands of farmers. The cornerstones of modern plant breeding were laid by Darwin and Mendel in the late 19th century. As the knowledge of genetics, plant pathology, and entomology have grown during the 20th century, plant breeders have made enormous contributions to increased food production throughout the world. There have been major plant breeding breakthroughs for maize and wheat, and promising research activities to raise yields in marginal production environments are ongoing. Since it is doubtful that significant production benefits will soon be forthcoming from the use of genetic engineering techniques with higher plants, especially polyploid species, most research funds for crop improvement should continue to be allocated for conventional plant breeding research.
Behavioral Phylogenies and the Direction of Evolution
Authors: Giddings Luther Val , Templeton Alan R.
Published: October 2006

A model for using mate preference data to deduce the direction of evolution between populations related by founder events or population bottlenecks is examined. Data from a wide range of organisms satisfying the necessary constraints of population structure are compatible with the model developed by K. Y. Kaneshiro from studies of Hawaiian
Drosophila
.
Direct Respiration of Lipids During Heat Production in the Inflorescence of
Philodendron selloum
Authors: Walker Dan B. , Gysi Jürg , Sternberg Leonel , DeNiro Michael J.
Published: October 2006

Respiration in the heat-generating, sterile florets of
Philodendron selloum
was examined by electron microscopy and carbon isotopic analysis of respired carbon dioxide. After the spathe unfolded, the florets switched from carbohydrate oxidation to lipid oxidation, which persisted during heating and for at least 2 days thereafter. The scarcity of glyoxysome-like organelles and the low catalase activity in this tissue indicate that the lipid was respired directly and not after conversion to carbohydrate by the glyoxylate shunt. Thus, lipid metabolism in this heat-generating plant tissue appears to mimic aspects of the biochemistry and physiology of heat production in some animal tissues.
Design Automation for Integrated Circuits
Authors: Newell Sydney B. , de Geus Aart J. , Rohrer Ronald A.
Published: October 2006

With the ever-increasing complexity of integrated circuits, manual design methods have become intolerably slow and error-prone. The use of computers to automate some or all of the design process is necessary to minimize both design time and error incidence. In this article are discussed the design and fabrication of integrated circuits, selected techniques of design automation, and the problems associated with such automation.
Middle Holocene Age of the Sunnyvale Human Skeleton
Authors: Taylor R. E. , Payen Louis A. , Gerow Bert , Donahue D. J. , Zabel T. H. , Jull A. J. T. , Damon P. E.
Published: October 2006

A morphologically modern human skeleton from Sunnyvale, California, previously dated by aspartic acid racemization to be approximately 70,000 years old and by uranium series isotopic ratios to be 8300 and 9000 years old, appears to be younger when dated by the carbon-14 method. Four carbon-14 determinations made by both decay and direct counting on three organic fractions of postcranial bone support a middle Holocene age assignment for the skeleton, probably in the range of 3500 to 5000 carbon-14 years before the present. This dating evidence is consistent with the geologic, archeological, and anthropometric relationships of the burial as well as previously determined carbon-14 determinations on associated materials.
Toxoplasma gondii
: Fusion Competence of Parasitophorous Vacuoles in Fc Receptor-Transfected Fibroblasts
Authors: Joiner K. A. , Fuhrman S. A. , Miettinen H. M. , Kasper L. H. , Mellman I.
Published: October 2006

After actively entering its host cells, the protozoan parasite
Toxoplasma gondii
resides in an intracellular vacuole that is completely unable to fuse with other endocytic or biosynthetic organelles. The fusion blocking requires entry of viable organisms but is irreversible: fusion competence of the vacuole is not restored if the parasite is killed after entry. The fusion block can be overcome, however, by altering the parasite's route of entry. Thus, phagocytosis of viable antibody-coated
T. gondii
by Chinese hamster ovary cells transfected with macrophage-lymphocyte Fc receptors results in the formation of vacuoles that are capable of both fusion and acidification. Phagocytosis and fusion appear to involve a domain of the Fc receptor cytoplasmic tail distinct from that required for localization at clathrin-coated pits. These results suggest that the mechanism of fusion inhibition is likely to reflect a modification of the vacuole membrane at the time of its formation, as opposed to the secretion of a soluble inhibitor by the parasite.
Neptunium and Americium Speciation in Selected Basalt, Granite, Shale, and Tuff Ground Waters
Authors: Cleveland Jess M. , Rees Terry F. , Nash Kenneth L.
Published: October 2006

Neptunium and americium are relatively insoluble in ground waters containing high sulfate concentrations, particularly at 90°C. The insoluble neptunium species is Np(IV); hence reducing waters should enhance its formation. Americium can exist only in the trivalent state under these conditions, and its solubility also should be representative of that of curium.
Uranus: Variability of the Microwave Spectrum
Authors: Gulkis S. , Olsen E. T. , Klein M. J. , Thompson T. J.
Published: October 2006

Radio astronomical observations of Uranus show that the radio emission spectrum is evolving in time. Ammonia vapor must be depleted in the Uranian atmosphere as Gulkis and his co-workers previously suggested. Since 1965, ammonia either has been decreasing in time or is a decreasing function of latitude, or both, provided that the radio emission is atmospheric in origin. If Uranus has an observable low-emissivity "surface," these trends may be reversed. The microwave observations made in 1965, at the time when the spin axis of Uranus was nearly perpendicular to the sun-Uranus line, are consistent with an atmospheric opacity profile that would be produced by saturated ammonia vapor in a predominantly hydrogen atmosphere. At the present time, when the spin axis of Uranus is nearly aligned with the sun-Uranus line, the measurements require an opacity that would be produced by saturated water vapor. A large thermal gradient between the pole and equator is ruled out.
Origin of Española Island and the Age of Terrestrial Life on the Galápagos Islands
Authors: Hall Minard L.
Published: October 2006

Geological studies of Española (Hood) Island, Galápagos, Ecuador, indicate that the island had a subaerial rather than a submarine origin. Because the younger lava flows are dated at 3 million years, Española has apparently existed as an island for at least that long. Thus terrestrial life may have existed or arrived on the Galápagos Islands at least 3 million years ago, more than twice as long as had been assumed.
Methylotrophic Bacteria: Biochemical Diversity and Genetics
Authors: Haber Christopher L. , Allen Larry N. , Zhao Shujie , Hanson Richard S.
Published: October 2006

Bacteria that are able to use methane as a sole carbon and energy source also carry out a broad range of biotransformations, some of which have industrial and environmental significance. Genetic studies on methylotrophs, including the use of recombinant DNA techniques, show promise for the isolation and cloning of genes coding for specific functions.
Heat Transfer Measurements of the 1983 Kilauea Lava Flow
Authors: Hardee H. C.
Published: October 2006

Convective heat flow measurements of a basaltic lava flow were made during the 1983 eruption of Kilauea volcano in Hawaii. Eight field measurements of induced natural convection were made, giving heat flux values that ranged from 1.78 to 8.09 kilowatts per square meter at lava temperatures of 1088 and 1128 degrees Celsius, respectively. These field measurements of convective heat flux at subliquidus temperatures agree with previous laboratory measurements in furnace-melted samples of molten lava, and are useful for predicting heat transfer in magma bodies and for estimating heat extraction rates for magma energy.
Sulfuric Acid Droplet Formation and Growth in the Stratosphere After the 1982 Eruption of El Chichón
Authors: Hofmann D. J. , Rosen J. M.
Published: October 2006

The eruption of El Chichón Volcano in March and April 1982 resulted in the nucleation of large numbers of new sulfuric acid droplets and an increase by nearly an order of magnitude in the size of the preexisting particles in the stratosphere. Nearly 10
7
metric tons of sulfuric acid remained in the stratosphere by the end of 1982, about 40 times as much as was deposited by Mount St. Helens in 1980.
Zonal Winds in the Central Equatorial Pacific and El Niño
Authors: Luther D. S. , Harrison D. E. , Knox R. A.
Published: October 2006

Easterly trade winds from near-equatorial islands in the central Pacific weakened before each El Niño between 1950 and 1978, except for the 1963 El Niño. The weakening of the easterlies and their later collapse did not occur uniformly over several months, but rather through a series of strong westerly wind bursts lasting 1 to 3 weeks. The bursts may force equatorial Kelvin waves in the ocean that can both initiate and sustain the sea surface warming characteristics of El Niño events.
A Climatic Freshening of the Deep Atlantic North of 50°N over the Past 20 Years
Authors: Brewer P. G. , Broecker W. S. , Jenkins W. J. , Rhines P. B. , Rooth C. G. , Swift J. H. , Takahashi T. , Williams R. T.
Published: October 2006

Observations made in summer 1981 show a significant and widespread decrease in salinity, averaging 0.02 per mil, in deep waters of the subpolar North Atlantic over the past two decades. This implies a relatively rapid response of deep water formation to climatic perturbation.
Iron-Stabilized Carbocations as Intermediates for Organic Synthesis
Authors: Pearson Anthony J.
Published: October 2006

Attachment of a transition metal moiety to an olefinic ligand presents the organic chemist with unequaled opportunities to control the regio- and stereospecificities of bond formation. Applications of cationic dienyliron-carbonyl complexes to a range of natural product syntheses have been developed. These applications show how the iron-carbonyl unit directs the regio- and stereochemistry of nucleophile addition. They also show that the iron-carbonyl unit can be used to stabilize otherwise inaccessible carbocations, thereby making them readily available as synthetic intermediates.
Protection of Mice Against the Lyme Disease Agent by Immunizing with Recombinant OspA
Authors: Fikrig Erol , Barthold Stephen W. , Kantor Fred S. , Flavell Richard A.
Published: October 2006

Lyme borreliosis is a tick-borne illness caused by
Borrelia burgdorferi
. The gene for outer surface protein A (OspA) from
B. burgdorferi
strain N40 was cloned into an expression vector and expressed in
Escherichia coli
. C3H/HeJ mice actively immunized with live transformed
E. coli
or purified recombinant OspA protein produced antibodies to OspA and were protected from challenge with several strains of
B. burgdorferi
. Recombinant OspA is a candidate for a vaccine for Lyme borreliosis.