bluuebunny/crossref_metadata_2025 huggingface dataset:
Waves in the OH Emissive Layer
Authors: Hersé M.
Published: October 2006

An instrument designed to take pictures of infrared spatial structures from space was flown on Spacelab 1. An image intensifier was used to give enough sensitivity and images were recorded on photographic film. The instrument worked perfectly and 1771 pictures were obtained during the night on 27 orbits (one picture every 16 seconds). Image processing of the data will yield information about the extension of large-scale structures and the relation between medium-scale structures and gravity waves.
Observations of Lyman-α Emissions of Hydrogen and Deuterium
Authors: Bertaux J. L. , Goutail F. , Kockarts G.
Published: October 2006

A spectrophotometer was flown on Spacelab 1 to study various mechanisms of Lyman-α emission in the upper atmosphere. The use of absorption cells filled with H
2
and D
2
gases allowed us to discriminate a number of weak Lyman-α emissions heretofore masked by the strong H geocoronal emission due to resonance scattering of solar photons. Preliminary results are presented on three topics: the first optical detection of the deuterium Lyman-α emission at 110 kilometers, with an intensity of 330 rayleighs indicating an eddy diffusion coefficient of 1.3 × 10
6
square centimeters per second; auroral proton precipitations seen on both the night and the day side; and an emission located above 250 kilometers of altitude, interpreted as the result of charge exchange of magnetospheric protons with geocoronal atoms.
Measurement of the Solar Spectral Irradiance from 200 to 3000 Nanometers
Authors: Thuillier G. , Goutail J. P. , Simon P. C. , Pastiels R. , Labs D. , Neckel H.
Published: October 2006

The solar spectrum experiment on Spacelab 1 measured 98 percent of the sun's total energy output. It improved the absolute accuracy of solar irradiance data, especially in the ultraviolet and infrared regions. In order to detect any variation in the spectrum on future shuttle flights, the data were obtained in a radiation scale that can be preserved with high precision over many years. The instrument performance and preliminary data reduction are described.
Phenomena Induced by Charged Particle Beams
Authors: Beghin C. , Lebreton J. P. , Maehlum B. N. , Troim J. , Ingsoy P. , Mīchau J. L.
Published: October 2006

The effects of electron beam emissions from Spacelab were recorded with onboard diagnostic instruments. The variation of the Spacelab-shuttle potential with respect to the ambient plasma near the scientific air lock was investigated. Data on the waves and instabilities triggered by the electron beams are discussed. Within the electron gyrofrequency and electron plasma frequency range, strong signals were detected by both electric and magnetic antennas during the beam emissions. The frequencies of the emitted waves were compared to the characteristic plasma frequencies to enable mode identification.
Radiobiological Advanced Biostack Experiment
Authors: Bücker H. , Horneck G. , Facius R. , Reitz G. , Schäfer M. , Schott J. U. , Beaujean R. , Enge W. , Schopper E. , Heinrich H. , Beer J. , Wiegel B. , Pfohl R. , François H. , Portal G. , Bonting S. L. , Graul E. H. , Rüther W. , Kranz A. R. , Bork U. , Koller-Lampert K. , Kirchheim B. , Starke M. E. , Planel H. , Delpoux M.
Published: October 2006

The radiobiological properties of the heavy ions of cosmic radiation were investigated on Spacelab 1 by use of biostacks, monolayers of biological test organisms sandwiched between thin foils of different types of nuclear track detectors. Biostacks were exposed to cosmic radiation at several locations with different shielding environments in the module and on the pallet. Evaluations of the physical and biological components of the experiment to date indicate that in general they survived the spaceflight in good condition. Dosimetric data are presented for the different shielding environments.
Observed Ozone Response to Variations in Solar Ultraviolet Radiation
Authors: Gille John C. , Smythe Charles M. , Heath Donald F.
Published: October 2006

During the winter of 1979, the solar ultraviolet irradiance varied with a period of 13.5 days and an amplitude of 1 percent. The zonal mean ozone values in the tropics varied with the solar irradiance, with an amplitude of 0.25 to 0.60 percent. This observation agrees with earlier calculations, although the response may be overestimated. These results imply changes in ozone at an altitude of 48 kilometers of up to 12 percent over an 11-year solar cycle. Interpretation of ozone changes in the upper stratosphere will require measurements of solar ultraviolet radiation at wavelengths near 200 nanometers.
The Open Society
Authors: Opel John R.
Published: October 2006

The open society, unlike the closed society, requires constant citizen thought and action to ensure that it will continue to survive and prosper. Today in the United States we should give particular attention to three immediate problems. We should reinvigorate our national economic health and international competitiveness, particularly by reducing our unprecedented budget deficits and reforming our tax system. We must strengthen our scientific and engineering vitality, particularly in graduate engineering education and in secondary school instruction in science and mathematics. And we should work with our allies in the free industrialized world to keep our international open society as open as possible, encouraging a flow of people and information and ideas across national boundaries while instituting sensible and efficient safeguards against leakage of critical military technology to the Soviet Union.
Pheromonal Control of Metamorphosis in the Pacific Sand Dollar,
Dendraster excentricus
Authors: Burke Robert D.
Published: October 2006

Competent larvae are induced to undergo metamorphosis by sand from a sand dollar bed or an aqueous extract of the sand. Gel permeation chromatography and high-performance liquid chromatography of the extract yielded a 980-dalton peptide that will induce metamorphosis between 10
-6
and 10
-5
molar. Extracts of whole adults and gonads were also able to induce metamorphosis, and adults can condition substrates to induce metamorphosis. Therefore, the initiation of metamorphosis in
Dendraster excentricus
is controlled by a pheromone released by adult sand dollars.
Multiple Thermal Maxima During the Holocene
Authors: Davis Owen K.
Published: October 2006

The astronomical theory of climatic change provides an alternative to the traditional chronology for Holocene climatic change, which calls for one thermal maximum about 6000 years ago. The theory predicts a series of maxima during the Holocene, one for each season. Because the relation of the perihelion to the spring equinox changes with a 22,000-year period, late summer insolation would have been greatest 5000 years ago, whereas early summer insolation would have been greatest 13,000 years ago. Climatic reconstructions based on the response of ecosystems to late summer climate indicate a later Holocene thermal maximum than paleoclimatic data sensitive to early summer climate. In southern Idaho, three different vegetation types indicate thermal maxima at different times during the Holocene, depending on the climatic variable controlling each type.
Ionospheric Sporadic-E Parameters: Long-Term Trends
Authors: Baggaley W. J.
Published: October 2006

The results of observations over 3½ solar cycles of ionosonde parameters describing sporadic-E patches (E
s
) are given for two Southern Hemisphere stations. Analysis has revealed systematic changes in the occurrence probabilities of ƒ
o
E
s
and ƒ
b
E
s
, changes that are independent of time of day or season. It is unlikely that observational effects can be entirely responsible for the trends, which suggest that major long-term changes may be occurring at E region heights.
Stimulation of Food Species Growth by Limpet Mucus
Authors: Connor Valerie M. , Quinn James F.
Published: October 2006

The trails of mucus secreted by certain species of intertidal limpets serve as adhesive traps for the microalgae that are their primary food resource. In addition, the mucus trails of two solitary homing limpets,
Lottia gigantea
and
Collisella scabra
, stimulate growth of the microalgae that the limpets consume. In contrast, the trails of an aggregating limpet,
Collisella digitalis
, do not stimulate microalgal growth. These results and their possible ecological significance are interpreted in light of the differences in the behavioral repertoires of the three limpet species.
Sieve Cells in Phloem of a Middle Devonian Progymnosperm
Authors: Wight David C. , Beck Charles B.
Published: October 2006

Phloem tissue from a Middle Devonian member of the Aneurophytales (Progymnospermopsida) is described. This may be the oldest firm evidence of conducting elements of the phloem, extending our knowledge of this tissue back some 35 million years. The discovery indicates a close phylogenetic relation between progymnosperms and gymnosperms and provides a basis for investigating patterns of specialization in the phloem of these groups of plants.
Periodicity of Extinctions in the Geologic Past: Deterministic Versus Stochastic Explanations
Authors: Kitchell Jennifer A. , Pena Daniel
Published: October 2006

The temporal spacing and the magnitude of major extinctions over the past 250 and 570 million years, based on the use of different metrics of extinction probability, are analyzed by comparing deterministic and stochastic explanations. The best-fitting time series model is a stochastic autoregressive model that displays a pseudoperiodic behavior with a cycle length of 31 million years for the past 250 million years, regardless of the metric of extinction probability. The periodicity lengthens and weakens when the analysis is extended to the entire Phanerozoic. The history of the probability of extinction for the entire Phanerozoic, based on time series analysis, does not support the reported bipartite distribution of Van Valen. Rather, the probability of extinction has decreased uniformly over Phanerozoic time whereas the inertia or stability of the biotic system after the Late Permian crisis has increased.
Pollen Feeding in an Orb-Weaving Spider
Authors: Smith Risa B. , Mommsen Thomas P.
Published: October 2006

Juvenile orb-weaving spiders appear in spring, when insect prey are scarce but when aerial plankton, such as pollen and fungus spores, is abundant. Microscopic organic matter may be the main food of orb-weaving spiderlings, with insects providing only a dietary supplement. Pollen, which is caught on the sticky spirals of
Araneus diadematus
orb webs, doubles the life expectancy of spiderlings and alters their web-spinning behavior, so that they spin more frequently than do fasting controls. Fungus spores do not have the same nutritional value as pollen and may be deleterious to the spiderlings.
Amazon Rain-Forest Fires
Authors: Sanford Robert L. , Saldarriaga Juan , Clark Kathleen E. , Uhl Christopher , Herrera Rafael
Published: October 2006

Charcoal is common in the soils of mature rain forests within 75 kilometers of San Carlos de Rio Negro in the north central Amazon Basin. Carbon-14 dates of soil charcoal from this region indicate that numerous fires have occurred since the mid-Holocene epoch. Charcoal is most common in tierra firme forest Oxisols and Ultisols and less common in caatinga and igapo forest soils. Climatic changes or human activities, or both, have caused rain-forest fires.
Climatic Forcing: Effects of El Niño on a Small, Temperate Lake
Authors: Strub P. Ted , Powell Thomas , Goldman Charles R.
Published: October 2006

Temperature profiles measured regularly for 21 years reveal the interannual differences in winter-to-summer heat gain in Castle Lake, California, a small subalpine lake. Year-to-year changes in large-scale climatic surface forcing, especially the amount of snowfall from February through April (which determines the date of thaw) coupled with the early heating and wind mixing after thaw, causes this interannual variation. The seasonal thermal structure for years in which the lake gains significantly more or less heat than normal—all of the El Niño years and several others—shows that the depth of the mixed layer and the mixing of heat into the stratified thermocline region control the storage of heat. The temperature of the mixed layer does not reflect abnormal thermal storage. Variations in mixing during early spring, which controls the heat content at Castle Lake, may also affect the annual average of the primary productivity.
Phytoplankton Bloom Produced by a Receding Ice Edge in the Ross Sea: Spatial Coherence with the Density Field
Authors: Smith Walker O. , Nelson David M.
Published: October 2006

Measurements of chlorophyll, particulate carbon, and biogenic silica concentrations near a receding ice edge off the coast of Victoria Land, Antarctica, indicated the presence of a dense phytoplankton bloom. The bloom extended 250 kilometers from the ice edge and was restricted to waters where the melting of ice had resulted in reduced salinity. The region involved was one of enhanced vertical stability, which may have favored phytoplankton growth, accumulation, or both. Epontic algae released from melting ice may have served as an inoculum for the bloom. Ratios of organic carbon to chlorophyll and biogenic silica to carbon were unusually high, resulting in high biogenic silica concentrations despite only moderately high chlorophyll levels.
Pollution Monitoring of Puget Sound with Honey Bees
Authors: Bromenshenk J. J. , Carlson S. R. , Simpson J. C. , Thomas J. M.
Published: October 2006

To show that honey bees are effective biological monitors of environmental contaminants over large geographic areas, beekeepers of Puget Sound, Washington, collected pollen and bees for chemical analysis. From these data, kriging maps of arsenic, cadmium, and fluoride were generated. Results, based on actual concentrations of contaminants in bee tissues, show that the greatest concentrations of contaminants occur close to Commencement Bay and that honey bees are effective as large-scale monitors.
Terminal Cretaceous Environmental Events
Authors: Officer Charles B. , Drake Charles L.
Published: October 2006

The geologic record of terminal Cretaceous environmental events indicates that iridium and other associated elements were not deposited instantaneously but during a time interval spanning some 10,000 to 100,000 years. The available geologic evidence favors a mantle rather than meteoritic origin for these elements. These results are in accord with the scenario of a series of intense eruptive volcanic events occurring during a relatively short geologic time interval and not with the scenario of a single large asteroid impact event.
Magnetochemistry of Ions in the
4
A
2
Electronic State
Authors: Carlin Richard L.
Published: October 2006

Each of the following ions with spin
S
= 3/2, octahedral chromium(III), five-coordinate iron(III), and tetrahedral cobalt(II), possesses a
4
A
2
ground state. The theory describing their paramagnetic properties is therefore the same, though some of the parameters change appreciably from ion to ion. This theory is described along with examples of experimental data. The implications of the paramagnetic properties for the magnetic ordering phenomena exhibited by complexes of these ions are also described.
Remote Sensing of the Magnetic Moment of Uranus: Predictions for Voyager
Authors: Hill T. W. , Dessler A. J.
Published: October 2006

Power is supplied to a planet's magnetosphere from the kinetic energy of planetary spin and the energy flux of the impinging solar wind. A fraction of this power is available to drive numerous observable phenomena, such as polar auroras and planetary radio emissions. In this report our present understanding of these power transfer mechanisms is applied to Uranus to make specific predictions of the detectability of radio and auroral emissions by the planetary radio astronomy (PRA) and ultraviolet spectrometer (UVS) instruments aboard the Voyager spacecraft before its encounter with Uranus at the end of January 1986. The power available for these two phenomena is (among other factors) a function of the magnetic moment of Uranus. The date of earliest detectability also depends on whether the predominant power source for the magnetosphere is planetary spin or solar wind. The magnetic moment of Uranus is derived for each power source as a function of the date of first detection of radio emissions by the PRA instrument or auroral emissions by the UVS instrument. If we accept the interpretation of ultraviolet observations now available from the Earth-orbiting International Ultraviolet Explorer satellite, Uranus has a surface magnetic field of at least 0.6 gauss, and more probably several gauss, making it the largest or second-largest planetary magnetic field in the solar system.
Separation Techniques Based on the Opposition of Two Counteracting Forces to Produce a Dynamic Equilibrium
Authors: O'Farrell Patrick H.
Published: October 2006

Useful compounds, whether produced by chemical synthesis or biological synthesis, often need to be purified from complex mixtures. Biochemists and chemists thus recognize the need for efficient new preparative purification techniques for product recovery. Such fractionation techniques must have high capacity and high resolution. In a novel group of separation methods suited to the preparative fractionation of proteins, antibiotics, and other classes of compounds, the chromatographic flow of a solute down the column is opposed by solute electrophoresis in the opposite direction. Useful separation is achieved when these two counteracting forces drive the solute to a unique equilibrium position within the separation chamber. The properties of chromatographic matrices, for example, gel-permeation matrices of various porosities, provide a means of establishing the unique equilibrium points. Extraordinary resolution and capacity are attainable by these methods.
Mechanisms in the Cycle of Violence
Authors: Dodge Kenneth A. , Bates John E. , Pettit Gregory S.
Published: October 2006

Two questions concerning the effect of physical abuse in early childhood on the child's development of aggressive behavior are the focus of this article. The first is whether abuse per se has deleterious effects. In earlier studies, in which samples were nonrepresentative and family ecological factors (such as poverty, marital violence, and family instability) and child biological variables (such as early health problems and temperament) were ignored, findings have been ambiguous. Results from a prospective study of a representative sample of 309 children indicated that physical abuse is indeed a risk factor for later aggressive behavior even when the other ecological and biological factors are known. The second question concerns the processes by which antisocial development occurs in abused children. Abused children tended to acquire deviant patterns of processing social information, and these may mediate the development of aggressive behavior.
Linkage of Early-Onset Familial Breast Cancer to Chromosome 17q21
Authors: Hall Jeff M. , Lee Ming K. , Newman Beth , Morrow Jan E. , Anderson Lee A. , Huey Bing , King Mary-Claire
Published: October 2006

Human breast cancer is usually caused by genetic alterations of somatic cells of the breast, but occasionally, susceptibility to the disease is inherited. Mapping the genes responsible for inherited breast cancer may also allow the identification of early lesions that are critical for the development of breast cancer in the general population. Chromosome 17q21 appears to be the locale of a gene for inherited susceptibility to breast cancer in families with early-onset disease. Genetic analysis yields a lod score (logarithm of the likelihood ratio for linkage) of 5.98 for linkage of breast cancer susceptibility to
D17S74
in early-onset families and negative lod scores in families with late-onset disease. Likelihood ratios in favor of linkage heterogeneity among families ranged between 2000:1 and greater than 10
6
:1 on the basis of multipoint analysis of four loci in the region.
A Silurian Soft-Bodied Biota
Authors: Mikulic Donald G. , Briggs Derek E. G. , Kluessendorf Joanne
Published: October 2006

A new Silurian (Llandoverian) biota from Wisconsin with a significant soft-bodied and lightly sclerotized component is dominated by arthropods and worms. The fauna includes the earliest well-preserved xiphosure, a possible marine uniramian, three new arthropods of uncertain affinity, and possibly the first Paleozoic leech. This may be only the second locality to yield a conodont animal. Lack of a normal shelly fauna suggests an unusual environment. The discovery adds significantly to the few such exceptionally preserved faunas known from Lower Paleozoic rocks.
Late Pleistocene Faunal Extinctions in Southern Patagonia
Authors: Markgraf Vera
Published: October 2006

Major environmental changes recorded in pollen records from various sites in southern Patagonia and Tierra del Fuego are also reflected in pollen and cuticle data from dung of the late Pleistocene groundsloth. The most prominent change was the large-scale reduction of steppe environment about 10,000 years ago, which coincides with the latest dates for extinctions of many large grazers such as the giant groundsloth. Stress on food resources for all the large grazers may well have hastened their extinction. Hunting pressure by paleoindians may have been the final blow.
Rare Earths: Atmospheric Signatures for Oil-Fired Power Plants and Refineries
Authors: Olmez Ilhan , Gordon Glen E.
Published: October 2006

The concentration pattern of rare earth elements on fine airborne particles (less than 2.5 micrometers in diameter) is distorted from the crustal abundance pattern in areas influenced by emissions from oil-fired plants and refineries. For example, the ratio of lanthanum to samarium is often greater than 20 compared to a crustal ratio less than 6. The unusual pattern apparently results from the distribution of rare earths in zeolite catalysts used in refining oil. Oil industry emissions perturb the rare earth pattern even at remote locations such as the Mauna Loa Observatory in Hawaii. Rare earth ratios are probably better for long-range tracing of oil emissions than vanadium and nickel concentrations because the ratios of rare earths on fine particles are probably not influenced by deposition and other fractionating processes. Emissions from oil-fired plants can be differentiated from those of refineries on an urban scale by the much smaller amounts of vanadium in the latter.
Priming and Human Memory Systems
Authors: Tulving Endel , Schacter Daniel L.
Published: October 2006

Priming is a nonconscious form of human memory, which is concerned with perceptual identification of words and objects and which has only recently been recognized as separate from other forms of memory or memory systems. It is currently under intense experimental scrutiny. Evidence is converging for the proposition that priming is an expression of a perceptual representation system that operates at a pre-semantic level; it emerges early in development, and access to it lacks the kind of flexibility characteristic of other cognitive memory systems. Conceptual priming, however, seems to be based on the operations of semantic memory.
The International Decline in Household Oil Use
Authors: Schipper Lee , Ketoff Andrea N.
Published: October 2006

In this article estimates are made of the permanent and reversible components of changes in heating oil use in major countries of the Organization for Economic Cooperation and Development. The components of the increase in oil use through the mid-1970's, and of the subsequent decline, are revealed. For seven countries, residential oil use decreased by 40 percent between 1972 and 1983, for a savings of about 1.2 million barrels per day (59 million metric tons of oil equivalent per year). One-third of this resulted from reductions in the number of homes heated with oil, the rest from reductions in oil use per oil-heated home. During that time, however, the size of these homes and the penetration of central heating increased significantly, so these figures underestimate the actual conservation achieved. Of the total oil savings, at least 46 percent are of a permanent nature, while the rest could be reversed with a continued slide in oil prices, although it seems likely that most of the savings will be maintained and may even increase.
P/Halley: The Quintessential Comet
Authors: Belton Michael J. S.
Published: October 2006

Halley's comet is the focus of an international scientific enterprise now under way. Ground-based astronomical observations are already yielding new information about the comet's nucleus and atmosphere. In the coming year, remote and in situ investigations from the ground, Earth orbit, Venus orbit, interplanetary space, and within the comet itself are expected to reveal much more. The climax of the enterprise will be the penetration of an armored European spacecraft into the center of the comet in March 1986.
Interparticle Collisions Driven by Ultrasound
Authors: Doktycz Stephen J. , Suslick Kenneth S.
Published: October 2006

Ultrasound has become an important synthetic tool in liquid-solid chemical reactions, but the origins of the observed enhancements remained unknown. The effects of high-intensity ultrasound on solid-liquid slurries were examined. Turbulent flow and shock waves produced by acoustic cavitation were found to drive metal particles together at sufficiently high velocities to induce melting upon collision. A series of transition-metal powders were used to probe the maximum temperatures and speeds reached during such interparticle collisions. Metal particles that were irradiated in hydrocarbon liquids with ultrasound underwent collisions at roughly half the speed of sound and generated localized effective temperatures between 2600°C and 3400°C at the point of impact for particles with an average diameter of ∼10 μm.
Palynological and Iridium Anomalies at Cretaceous-Tertiary Boundary, South-Central Saskatchewan
Authors: Nichols D. J. , Jarzen D. M. , Orth C. J. , Oliver P. Q.
Published: October 2006

The Cretaceous-Tertiary boundary in south-central Saskatchewan is marked by coincident anomalies in abundance of iridium and fern spores at the extinction level of a suite of Cretaceous pollen taxa. Evidence of disruption of the terrestrial flora includes the fern-spore abundance anomaly and local extinction of as much as 30 percent of angiosperm species. The reorganized earliest Tertiary flora is made up largely of surviving species that assumed new roles of dominance. Persistence of climatically sensitive taxa across the boundary indicates that if paleoclimate was altered by the terminal Cretaceous event, it returned quickly to the pre-event condition.
Cation-Ratio and Accelerator Radiocarbon Dating of Rock Varnish on Mojave Artifacts and Landforms
Authors: Dorn Ronald I. , Bamforth D. B. , Cahill T. A. , Dohrenwend J. C. , Turrin B. D. , Donahue D. J. , Jull A. J. T. , Long A. , Macko M. E. , Weil E. B. , Whitley D. S. , Zabel T. H.
Published: October 2006

The first accelerator radiocarbon dates of rock varnishes are reported along with potassium/argon ages of lava flows and conventional radiocarbon dates of pluvial lake shorelines, in an empirical calibration of rock varnish K
+
+ Ca
2+
/Ti
4+
ratios with age in the Mojave Desert, eastern California. This calibration was used to determine the cation-ratio dates of 167 artifacts. Although cation-ratio dating is an experimental method, some dates suggest human occupation of the Mojave Desert in the late Pleistocene.
Crystal Structures at Megabar Pressures Determined by Use of the Cornell Synchrotron Source
Authors: Vohra Yogesh K. , Brister Keith E. , Weir Samuel T. , Duclos Steven J. , Ruoff Arthur L.
Published: October 2006

X-ray diffraction studies have been carried out on alkali halide samples 10 micrometers in diameter (volume 10
-9
cubic centimeter) subjected to megabar pressures in the diamond anvil cell. Energy-dispersive techniques and a synchrotron source were used. These measurements can be used to detect crystallographic phase transitions. Cesium iodide was subjected to pressures of 95 gigapascals (fractional volume of 46 percent) and rubidium iodide to pressures of 89 gigapascals (fractional volume of 39 percent). Cesium iodide showed a transformation from the cubic B2 phase (cesium chloride structure) to a tetragonal phase and then to an orthorhombic phase, which was stable to 95 gigapascals. Rubidium iodide showed only a transition from the low-pressure cubic B1 phase (sodium chloride structure) to the B2 phase, which was stable up to 89 gigapascals.
Safeguarding Our Military Space Systems
Authors: May Michael M.
Published: October 2006

The vulnerability of military space systems depends on their orbits, functions, and other characteristics. The high-altitude satellites needed for warning and communications in particular could be vulnerable to prompt destruction by certain space-based systems and, in the future, possibly by ground-based high power lasers. A combination of passive countermeasures and arms control agreements could give these satellites some protection against such attack. Deployment of strategic defensive systems with the capability to reach far into space would invalidate this approach.
Lower Cretaceous Angiosperm Flowers: Fossil Evidence on Early Radiation of Dicotyledons
Authors: Crane Peter R. , Friis Else Marie , Pedersen Kaj Raunsgaard
Published: October 2006

Three-dimensionally preserved unisexual angiosperm flowers and inflorescences have been recovered from the Lower Cretaceous Patapsco Formation (Potomac Group) of eastern North America, in sediments palynologically dated as late Albian, approximately 100 million years old. In situ tricolpate pollen shows that the flowers were produced by some of the earliest higher (nonmagnoliid) dicotyledons, and the morphology of pollen, flowers, and inflorescences indicates a close relation to extant Platanaceae. Combined with architectural and cuticular features of associated leaves these floral remains suggest that
Platanus
-like plants with unisexual, probably insect-pollinated flowers were an important element in the mid-Cretaceous diversification of dicotyledonous flowering plants.
A Comparison of SIR-B Directional Ocean Wave Spectra with Aircraft Scanning Radar Spectra
Authors: Beal R. C. , Monaldo F. M. , Tilley D. G. , Irvine D. E. , Walsh E. J. , Jackson F. C. , Hancock D. W. , Hines D. E. , Swift R. N. , Gonzalez F. L. , Lyzenga D. R. , Zambresky L. F.
Published: October 2006

Directional ocean wave spectra derived from Shuttle Imaging Radar-B (SIR-B) L-band imagery collected off the coast of southern Chile on 11 and 12 October 1984 were compared with independent spectral estimates from two airborne scanning radars. In sea states with significant wave heights ranging from 3 to 5 meters, the SIR-B-derived spectra at 18° and 25° off nadir yielded reasonable estimates of wavelengths, directions, and spectral shapes for all wave systems encountered, including a purely azimuth-traveling system. A SIR-B image intensity variance spectrum containing predominantly range-traveling waves closely resembles an independent aircraft estimate of the slope variance spectrum. The prediction of a U.S. Navy global spectral ocean wave model on 11 October 1984 exhibited no significant bias in dominant wave number but contained a directional bias of about 30° with respect to the mean of the aircraft and spacecraft estimates.
Differential Reflex Activity Determines Claw and Closer Muscle Asymmetry in Developing Lobsters
Authors: Govind C. K. , Pearce Joanne
Published: October 2006

The paired claws and closer muscles of the lobster,
Homarus americanus
, are identical in the early juvenile stages, but subsequently differentiate into a stout crusher claw with only slow fibers and a slender cutter with largely fast fibers. Rearing with different substrates or exercise of the claws revealed that claw laterality is determined in the central nervous system by differential reflex activity in the paired claws; the side with greater activity becomes the crusher, while the contralateral side becomes the cutter.
The 1985 Central Chile Earthquake: A Repeat of Previous Great Earthquakes in the Region?
Authors: Comte D. , Eisenberg A. , Lorca E. , Pardo M. , Ponce L. , Saragoni R. , Singh S. K. , Suárez G.
Published: October 2006

A great earthquake (surface-wave magnitude, 7.8) occurred along the coast of central Chile on 3 March 1985, causing heavy damage to coastal towns. Intense foreshock activity near the epicenter of the main shock occurred for 11 days before the earthquake. The aftershocks of the 1985 earthquake define a rupture area of 170 by 110 square kilometers. The earthquake was forecast on the basis of the nearly constant repeat time (83 ± 9 years) of great earthquakes in this region. An analysis of previous earthquakes suggests that the rupture lengths of great shocks in the region vary by a factor of about 3. The nearly constant repeat time and variable rupture lengths cannot be reconciled with time- or slip-predictable models of earthquake recurrence. The great earthquakes in the region seem to involve a variable rupture mode and yet, for unknown reasons, remain periodic. Historical data suggest that the region south of the 1985 rupture zone should now be considered a gap of high seismic potential that may rupture in a great earthquake in the next few tens of years.
Hydrogen Sulfide Oxidation Is Coupled to Oxidative Phosphorylation in Mitochondria of
Solemya reidi
Authors: Powell Mark A. , Somero George N.
Published: October 2006

Solemya reidi
, a gutless clam found in sulfide-rich habitats, contains within its gills bacterial symbionts thought to oxidize sulfur compounds and provide a reduced carbon food source to the clam. However, the initial step or steps in sulfide oxidation occur in the animal tissue, and mitochondria isolated from both gill and symbiont-free foot tissue of the clam coupled the oxidation of sulfide to oxidative phosphorylation [adenosine triphosphate (ATP) synthesis]. The ability of
Solemya reidi
to exploit directly the energy in sulfide for ATP synthesis is unprecedented, and suggests that sulfide-habitat animals that lack bacterial symbionts may also use sulfide as an inorganic energy source.
Molecular Transformations on Single Crystal Metal Surfaces
Authors: Madix R. J.
Published: October 2006

One of the primary objectives of modern surface chemistry of transition metals is the synthesis of surface compounds and complexes and the understanding of their reactivity, structure, and bonding. Such considerations are paramount for advancing understanding of catalysis, adhesion, organic thin-film growth, and electrocatalysis. On selected metals, particularly copper, silver, and gold, selective scission of X-H bonds (where X is oxygen, carbon, nitrogen, or sulfur) by surface-bound atomic oxygen occurs to form moderately stable species that can be isolated for further study. Selective oxidation reactions may occur heterogeneously by means of this novel oxygen- activated route. Furthermore, this selective chemistry offers a paradigm for synthesis of a wide variety of surface organometallic complexes, whose formation can be predicted from acid-base principles. These subjects are discussed in this article with emphasis on their role in catalytic oxidation cycles.
North American—Pacific Relative Plate Motion in Southern California from Interferometry
Authors: Lyzenga Gregory A. , Golombek Matthew P.
Published: October 2006

Very long baseline interferometry measurements of baselines crossing the San Andreas fault zone in southern California have provided observational constraints on rates of elastic tectonic strain accumulation. The single site located near this fault (the Jet Propulsion Laboratory site) moves in a direction concordant with the Pacific plate motion vector but at approximately half the net rate relative to North America. This motion agrees approximately in amount with geologically determined displacement rates on the San Andreas fault alone but not with the local strike of the fault. When considered together with complementary geodetic data, these results suggest a complex relation between the short-term accumulation of elastic strain and its permanent accommodation on existing faults.
Dark Matter, Structure, and Strings
Authors: Waldrop M. Mitchell
Published: October 2006

In late July, about 150 astronomers gathered at the University of California, Santa Cruz, for a 2-week workshop on "Nearly Normal Galaxies." As the title suggests, the discussion was wide-ranging. Yet two issues stood out: dark matter and the large-scale structure. In itself this was hardly surprising, since these two issues have haunted extragalactic astronomy for nearly a decade. Indeed, they are central to an understanding of how galaxies formed. But some of the most dramatic findings have only been announced this year. Thus, the Santa Cruz workshop came at an especially opportune moment. In the following briefings, Research News draws on the workshop presentations to summarize astronomers' latest thinking on these subjects.
The Galactic Center: Is It a Massive Black Hole?
Authors: Lo K. Y.
Published: October 2006

Studies of active galactic nuclei constitute one of the major efforts in astronomy. Massive black holes are the most likely source for the enormous energy radiated from such nuclei. Observations reviewed here suggest unusual activity and the possible existence of a massive black hole in the nucleus of our galaxy. Because of its proximity to Earth, our galactic nucleus can be observed in unsurpassed detail and may serve as the Rosetta stone both for deciphering active galactic nuclei and for confirming the existence of a massive black hole.
Quasars at 25
Authors: Trimble Virginia , Woltjer Lodewijk
Published: October 2006

In the quarter century since the first optical identification of a "radio star" (3C 48), astronomers have come to general agreement that the underlying quasar energy source is accretion onto a massive black hole. There is much less agreement on the detailed physics of the processes by which this energy is converted to the forms observed, but this has not prevented the objects from serving as valuable probes of the universe at distant times and places.
Experimental Methods in the Political Economy of Exchange
Authors: Smith Vernon L.
Published: October 2006

Traditionally, economics has been considered a nonexperimental science. In the last quarter century experimental methods have become a growing part of the economist's effort to more fully understand how individual motivation, individual information, and exchange rules relate to market outcomes in different institutions. Empirical support has been found in a wide variety of different experiments for the theoretical proposition that markets serve to aggregate the dispersed information of individuals to produce wealth-creating outcomes for society. A number of different experiments are presented to illustrate the type of questions addressed, including some in which the process is governed by political institutions such as majority rule.
Very Long Baseline Interferometric Observations Made with an Orbiting Radio Telescope
Authors: Levy G. S. , Linfield R. P. , Ulvestad J. S. , Edwards C. D. , Jordan J. F. , Di Nardo S. J. , Christensen C. S. , Preston R. A. , Skjerve L. J. , Stavert L. R. , Burke B. F. , Whitney A. R. , Cappallo R. J. , Rogers A. E. E. , Blaney K. B. , Maher M. J. , Ottenhoff C. H. , Jauncey D. L. , Peters W. L. , Nishimura T. , Hayashi T. , Takano T. , Yamada T. , Hirabayashi H. , Morimoto M. , Inoue M. , Shiomi T. , Kawaguchi N. , Kunimori H.
Published: October 2006

An orbiting spacecraft and ground observatories have been used to obtain interferometric observations of cosmic radio sources. The Tracking and Data Relay Satellite System (TDRSS) was used as the orbiting observatory in conjunction with two 64-meter radio telescopes at ground observatories, one in Australia and one in Japan. The quasars 1730-130 (NRAO 530), 1510-089, and 1741-038 were observed at a frequency of 2.3 gigahertz, and a maximum projected baseline of 1.4 earth diameters was achieved. All quasar observations for which valid data were acquired resulted in detected fringes. Many of the techniques proposed for a dedicated very long baseline interferometry observatory in space were used successfully in this experiment.
The Little Ice Age as Recorded in the Stratigraphy of the Tropical Quelccaya Ice Cap
Authors: Thompson L. G. , Mosley-Thompson E. , Dansgaard W. , Grootes P. M.
Published: October 2006

The analyses of two ice cores from a southern tropical ice cap provide a record of climatic conditions over 1000 years for a region where other proxy records are nearly absent. Annual variations in visible dust layers, oxygen isotopes, microparticle concentrations, conductivity, and identification of the historical (A.D. 1600) Huaynaputina ash permit accurate dating and time-scale verification. The fact that the Little Ice Age (about A.D. 1500 to 1900) stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event.
Transient and Stable Expression of the Firefly Luciferase Gene in Plant Cells and Transgenic Plants
Authors: Ow David W. , Wood Keith V. , DeLuca Marlene , de Wet Jeffrey R. , Helinski Donald R. , Howell Stephen H.
Published: October 2006

The luciferase gene from the firefly,
Photinus pyralis
, was used as a reporter of gene expression by light production in transfected plant cells and transgenic plants. A complementary DNA clone of the firefly luciferase gene under the control of a plant virus promoter (cauliflower mosaic virus 35
S
RNA promoter) was introduced into plant protoplast cells (
Daucus carota
) by electroporation and into plants (
Nicotiana tabacum
) by use of the
Agrobacterium tumefaciens
tumor-inducing plasmid. Extracts from electroporated cells (24 hours after the introduction of DNA) and from transgenic plants produce light when mixed with the substrates luciferin and adenosine triphosphate. Light produced by the action of luciferase was also detected in undisrupted leaves or cells in culture from transgenic plants incubated in luciferin and in whole transgenic plants "watered" with luciferin. Although light was detected in most organs in intact, transgenic plants (leaves, stems, and roots), the pattern of luminescence appeared to reflect both the organ-specific distribution of luciferase and the pathway for uptake of luciferin through the vasculature of the plant.
Venus: Dead or Alive?
Authors: Taylor Harry A. , Cloutier Paul A.
Published: October 2006

In situ nightside electric field observations from the Pioneer Venus Orbiter have been interpreted as evidence of extensive lightning in the lower atmosphere of Venus. The scenario, including proposed evidence of clustering of lightning over surface highland regions, has encouraged the acceptance of currently active volcanic output as part of several investigations of the dynamics and chemistry of the atmosphere and the geology of the planet. However, the correlation between the 100-hertz electric field events attributed to lightning and nightside ionization troughs resulting from the interaction of the solar wind with the ionosphere indicates that the noise results from locally generated plasma instabilities and not from any behavior of the lower atmosphere. Furthermore, analysis of the spatial distribution of the noise shows that it is not clustered over highland topography, but rather occurs at random throughout the latitude and longitude regions sampled by the orbiter during the first 5 years of operation, from 1978 to 1984. Thus the electric field observations do not identify lightning and do not provide a basis for inferring the presence of currently active volcanic output. In the absence of known evidence to the contrary, it appears that Venus is no longer active.
Microcomputers and Phylogenetic Analysis
Authors: Fink William L.
Published: October 2006

The programs discussed above show how microcomputers have added to the arsenal of systematic biologists. This is a rapidly developing field, and there are no doubt major changes on the horizon. Swofford is working on a new version of PAUP that will have some of the interactive features of MacClade (and will not require a math coprocessor) and there are efforts under way to make PAUP available on Macintosh. PHYLIP has undergone a steady evolution since its release, and Felsenstein has plans to continue that policy. A microcomputer descendant of the large mainframe program PHYSYS, authored by James S. Farris, is supposed to be forthcoming before the end of the year.

Just as this review was being completed, J. Rohlf and R. Sokal of the State University of New York at Stony Brook unveiled a beta-test microcomputer version of their phenetic program package, NT-SYS. Inasmuch as it was not in release form and does not include algorithms specifically designed to do phylogenetic analysis, it has not been included here (although some phenetic techniques, such as UPGMA, produce results similar to parsimony trees under certain assumptions).
The Need to Reform Personal Injury Law Leaving Scientific Disputes to Scientists
Authors: Sugarman Stephen D.
Published: October 2006

Personal injury law is staggeringly inefficient as a system of victim compensation. There is little reason to assume that it importantly curtails unreasonably dangerous conduct, yet there is good reason to conclude that it promotes socially undesirable behavior. Moreover, the tort law system ill serves the goal of individual justice, in part because it assumes that lay juries can correctly decide complex scientific issues. Several methods of replacing tort law with other compensation systems are surveyed and a specific, balanced reform package is proposed.
Induced Resistance and Interspecific Competition Between Spider Mites and a Vascular Wilt Fungus
Authors: Karban Richard , Adamchak Rodney , Schnathorst William C.
Published: October 2006

The fungal pathogen
Verticillium dahliae
was less likely to cause symptoms of verticillium wilt on cotton seedlings that had been previously exposed to spider mites than on unexposed cotton seedlings. Conversely, populations of the spider mite
Tetranychus urticae
grew less rapidly on seedlings that had been inoculated with
V. dahliae
than on uninoculated controls. Changes caused by pathogen or herbivore attack reduced the suitability of the host plant to a diversity of organisms. This result suggests that highly unrelated organisms that share a host plant may interact strongly.
Dianion Stabilization by (M(C
5
(CH
3
)
5
)
2
)
+
: Theoretical Evidence for a Localized Ring in (DDQ)
2-
Authors: Miller Joel S. , Dixon David A.
Published: October 2006

Organic dianions have been stabilized by (M(C
5
(CH
3
)
5
)
2
)
+
, where M is iron or cobalt. This has allowed the structural and spectroscopic characterization of these dianions. The structure of (M(C
5
(CH
3
)
5
)
2
)
2
+
(DDQ)
2-
, where DDQ is 2,3-dichloro-5,6-dicyanobenzoquinone, has been determined by x-ray crystallography. The structure of (DDQ)
2-
is consistent with ab initio molecular orbital calculations that suggest a localized as opposed to a delocalized (aromatic) ring structure.
Two Gamma-Ray Sources and Ancient Guest Stars
Authors: Wang Zhen-Ru
Published: October 2006

On the basis of the fact that the youngest neutron stars such as the Crab pulsar and the Vela pulsar emit strong gamma-ray radiation, it is suggested that a few gamma-ray sources may be identified with young compact sources formed in the events of guest stars. Two such sources, 2CG 353+16 and 2CG 054+01, are identified with guest stars observed in the 14th century B.C. and A.D. 1230, respectively.