bluuebunny/crossref_metadata_2025 huggingface dataset:
Competition Among Courting Male Moths: Male-to-Male Inhibitory Pheromone
Authors: Hirai K. , Shorey H. H. , Gaston Lyle K.
Published: October 2006

The behavioral function of a pheromone released by males of the armyworm moth
Pseudaletia unipuncta
was investigated both in laboratory wind-tunnel experiments and in experiments with moth-baited traps in the field. Such male moth scents have been thought to act at close range as sexual stimulants for females of the same species. However, the only obvious effect of the
P. unipuncta
male pheromone was upon other males, decreasing their tendency to approach sexually receptive, pheromone-releasing females and to exhibit copulatory behavior when near those females. The adaptive significance of the male pheromone may be related to the increased reproductive efficiency that results if multiple males are prevented from competing for a single female.
Viking Bistatic Radar Observations of the Hellas Basin on Mars: Preliminary Results
Authors: Simpson R. A. , Tyler G. L. , Brenkle J. P. , Sue M.
Published: October 2006

Preliminary reduction of Viking bistatic radar data gives root-mean-square surface slopes in the Hellas basin on Mars of about 4° on horizontal scales averaged over 10 centimeters to 100 meters. This roughness decreases slightly with position along the ground track, south to north. The dielectric constant in this area appears to be approximately 3.1, greater than the martian average. These values are characteristic of lunar maria and are similar to those found near the Viking lander site in Chryse with the use of Earth-based radar.
Activation Volume for Creep in the Upper Mantle
Authors: Ross John V. , Ave'Lallemant Hans G. , Carter Neville L.
Published: October 2006

The activation volume for creep,
V
* of olivine-rich rocks has been determined in pressure-differential creep experiments on dunite at temperatures from 1100° to 1350°C and confining pressures from 5 to 15 kilobars. Values of
V
* range from 10.6 to 15.4 cubic centimeters per mole with a mean value of 13.4 cubic centimeters per mole, near that expected for oxygen ion self-diffusion. The quantity
V
* is incorporated into existing flow equations; in combination with observations on naturally deformed mantle xenoliths, estimates are given of the variation with depth of stress, strain rate, and viscosity.
Heat Storage in the Oceanic Upper Mixed Layer Inferred from Landsat Data
Authors: Mollo-Christensen Erik , Mascarenhas Affonso da S.
Published: October 2006

From the spacing of internal wave packets generated by tidal flow over topography, one can determine their propagation speed. The propagation speed depends upon the density anomaly and depth of the upper mixed layer. Attributing the density anomaly to temperature only, one can calculate the heat storage in the upper oceanic layer. On the basis of Landsat images of the New England continental shelf, the heat storage calculated from satellite data has been compared with available in situ observations. The data show that the method may have merit and is deserving of further refinement.
Encounter with Venus
Authors: Colin Lawrence
Published: October 2006

This report is an introduction to the accompanying collection of initial results from the successful Pioneer Venus orbiter and mutiprobe missions that encountered Venus on 4 December and 9 December 1978, respectively. The mission features are briefly described and furnish data accumulated over the first 30 days of the mission.
The Polar Ionosphere of Venus Near the Terminator from Early Pioneer Venus Orbiter Radio Occultations
Authors: Kliore Arvydas J. , Woo Richard , Armstrong John W. , Patel Indu R. , Croft Thomas A.
Published: October 2006

Fourteen profiles of electron density in the ionosphere of Venus were obtained by the dual-frequency radio occultation method with the Pioneer Venus orbiter between 5 and 30 December 1978. The solar zenith angles for these measurements were between about 85° and 92° , and the latitudes ranged from about 81° to 88° (ecliptic north). In addition to the expected decrease in peak electron density from about 1.5 × 10
3
to 0.5 × 10
3
per cubic centimeter with increasing solar zenith angle, a region of almost constant electron density above about 250 kilometers was observed. The ionopause height varies from about 300 to 700 kilometers and seems to be influenced by diurnal changes in solar wind conditions. The structures of the profiles are consistent with models in which O
2
+
dominates near the ionization peak and is replaced by O
+
at higher altitudes.
Venus Thermosphere: In situ Composition Measurements, the Temperature Profile, and the Homopause Altitude
Authors: von Zahn U. , Krankowsky D. , Mauersberger K. , Nier A. O. , Hunten D. M.
Published: October 2006

The neutral mass spectrometer on board the Pioneer Venus multiprobe bus measured composition and structural parameters of the dayside Venus upper atmosphere on 9 December 1978. Carbon dioxide and helium number densities were 6 × 10
9
and 5 × 10
6
per cubic centimeter, respectively, at an altitude of 150 kilometers. The mixing ratios of both argon-36 and argon-40 were approximately 80 parts per million at an altitude of 135 kilometers. The exospheric temperature from 160 to 170 kilometers was 285 ± 10 K. The helium homopause was found at an altitude of about 137 kilometers.
Preliminary Results of the Pioneer Venus Nephelometer Experiment
Authors: Ragent Boris , Blamont Jacques
Published: October 2006

Preliminary results of the nephelometer experiments conducted aboard the large sounder, day, north, and night probes of the Pioneer Venus mission are presented. The vertical structures of the Venus clouds observed simultaneously at each of the four locations from altitudes of from 63 kilometers to the surface are compared, and similarities and differences are noted. Tentative results from attempting to use the data from the nephelometer and cloud particle size spectrometer on the sounder probe to identify the indices of refraction of cloud particles in various regions of the Venus clouds are reported. Finally the nephelometer readings for the day probe during impact on the surface of Venus are presented.
Binary Asteroids: Evidence for Their Existence from Lightcurves
Authors: Tedesco Edward F.
Published: October 2006

The lightcurves of the asteroids 49 Pales and 171 Ophelia bear a striking resemblance to those of eclipsing binary stars. This evidence suggests that these asteroids are binary objects. Asteroids belonging to the Themis dynamical family have unusual lightcurves, possibly due to satellite events; these unusual lightcurves suggest that multiple objects may be formed during the disruption of asteroids in collisional events.
Dating and Context of Rock Engravings in Southern Africa
Authors: Butzer Karl W. , Fock Gerhai J. , Scott Louis , Stuckenrath Robert
Published: October 2006

Rock art is seldom recovered from sealed archeological contexts and is therefore difficult to date or integrate with other artifactual assemblages. South African engravings, found on low rocks at open-air sites, exemplify the problem. Multiscale spatial study of technique, thematic variation, faunal content, geoarcheological patterning, settlement history, and ethno-archeological setting provides coherent information on environment, time, and group identity. The major periods of naturalistic animal engravings coincide with wetter and warmer climates about 3200 to 2500 and 2250 to 1800 years before present, but the earliest engravings may be older than 4000 years. Geometric designs were favored after 1300 years before present, when climate was drier and when one identity-conscious population of Bushman engravers first encountered domesticated animals.
Paleocurrent Indicators in Deep-Sea Sediment
Authors: Ellwood Brooks B. , Ledbetter Michael T.
Published: October 2006

The fabric and texture of deep-sea sediments have been used to detect periods of high-velocity bottom-water flow through the Vema Channel in the southwest Atlantic Ocean. In addition, the alignment of the long axis of magnetic grains has been used to indicate the direction of bottom-water flow.
LAV Revisited: Origins of the Early HIV-1 Isolates from Institut Pasteur
Authors: Wain-Hobson Simon , Vartanian Jean-Pierre , Henry Michel , Chenciner Nicole , Cheynier Rémi , Delassus Sylvie , Martins Livia Pedroza , Sala Monica , Nugeyre Marie-Thérèse , Guétard Denise , Klatzmann David , Gluckman Jean-Claude , Rozenbaum Willy , Barré-Sinoussi Françoise , Montagnier Luc
Published: October 2006

Two of the first human immunodeficiency virus type-1 (HIV-1) strains isolated were authenticated by reanalyzing original cultured samples stored at the Collection Nationale de Culture des Microorganismes as well as uncultured primary material. Cloned polymerase chain reaction products were used to analyze coding sequences of the V3 loop in the gp120 glycoprotein. The original isolate HIV-1 Bru, formerly called LAV, was derived from patient BRU. HIV-1 Lai was derived from patient LAI and contaminated a HIV-1 Bru culture between 20 July and 3 August 1983. The culture became, in effect, HIV-1 Lai, identifiable by a unique motif in the V3 loop. Because of this contamination two, rather than one, HIV-1 isolates were sent to the Laboratory of Tumor Cell Biology at the National Cancer Institute on 23 September 1983. Original HIV-1 Bru was indeed present in the sample marked JBB/LAV. However the M2T-/B sample harbored HIV-1 Lai, a strain capable of growing on established cell lines. The striking similarity between HIV-1 Lai (formerly LAV-Bru) and HTLV-3B sequences remains.
The Moon: Sources of the Crustal Magnetic Anomalies
Authors: Hood L. L. , Coleman P. J. , Wilhelms D. E.
Published: October 2006

Previously unmapped Apollo 16 subsatellite magnetometer data collected at low altitudes over the lunar near side are presented. Medium-amplitude magnetic anomalies exist over the Fra Mauro and Cayley Formations (primary and secondary basin ejecta emplaced 3.8 to 4.0 billion years ago) but are nearly absent over the maria and over the craters Copernicus, Kepler, and Reiner and their encircling ejecta mantles. The largest observed anomaly (radial component ∼21 gammas at an altitude of 20 kilometers) is exactly correlated with a conspicuous light-colored deposit on western Oceanus Procellarum known as Reiner γ. Assuming that the Reiner γ deposit is the source body and estimating its maximum average thickness as 10 meters, a minimum mean magnetization level of 5.2 ± 2.4 × 10
–2
electromagnetic units per gram, or ∼500 times the stable magnetization component of the most magnetic returned sample, is calculated. An age for its emplacement of ≲ 2.9 billion years is inferred from photogeologic evidence, implying that magnetization of lunar crustal materials must have continued for a period exceeding 1 billion years.
CARNA 5, the Small Cucumber Mosaic Virus—Dependent Replicating RNA, Regulates Disease Expression
Authors: Waterworth H. E. , Kaper J. M. , Tousignant M. E.
Published: October 2006

CARNA 5, the small cucumber mosaic virus-dependent replicating RNA which is the causal agent of lethal tomato necrosis disease, causes a drastic reduction of disease symptoms in at least two other plant species. Satellite-like RNA's associated with plant viruses have a disease-regulating function.
Fasting Decreases Triiodothyronine Receptor Capacity
Authors: Schussler George C. , Orlando Joseph
Published: October 2006

Fasting decreases the ratio of hepatic nuclear to serum triiodothyronine (T
3
) by diminishing the binding capacity of nuclear T
3
receptors. In combination with the lower serum T
3
concentration caused by fasting, the decrease in receptor content results in a marked decrease in nuclear T
3
-receptor complexes. The changes in T
3
receptor content and circulating T
3
in fasted animals appear to be independent synergistic adaptations for caloric conservation in the fasted state. Unlike changes in hormonal level, the modification of nuclear receptor content provides a mechanism that may protect cells with a low caloric reserve independently of the metabolic status of the whole animal.
Structures of Larger Proteins in Solution: Three- and Four-Dimensional Heteronuclear NMR Spectroscopy
Authors: Clore G. Marius , Gronenborn Angela M.
Published: October 2006

Three- and four-dimensional heteronuclear nuclear magnetic resonance (NMR) spectroscopy offers dramatic improvements in spectral resolution by spreading through-bond and through-space correlations in three and four orthogonal frequency axes. Simultaneously, large heteronuclear couplings are exploited to circumvent problems due to the larger linewidths that are associated with increasing molecular weight. These novel experiments have been designed to extend the application of NMR as a method for determining three-dimensional structures of proteins in solution beyond the limits of conventional two-dimensional NMR (∼100 residues) to molecules in the 150- to 300-residue range. This potential has recently been confirmed with the determination of the high-resolution NMR structure of a protein greater than 150 residues, namely, interleukin-1β.
Toward a Science of Metabolic Engineering
Authors: Bailey James E.
Published: October 2006

Application of recombinant DNA methods to restructure metabolic networks can improve production of metabolite and protein products by altering pathway distributions and rates. Recruitment of heterologous proteins enables extension of existing pathways to obtain new chemical products, alter posttranslational protein processing, and degrade recalcitrant wastes. Although some of the experimental and mathematical tools required for rational metabolic engineering are available, complex cellular responses to genetic perturbations can complicate predictive design.
Venus Upper Atmosphere Neutral Gas Composition: First Observations of the Diurnal Variations
Authors: Niemann H. B. , Hartle R. E. , Hedin A. E. , Kasprzak W. T. , Spencer N. W. , Hunten D. M. , Carignan G. R.
Published: October 2006

Measurements of the composition, temperature, and diurnal variations of the major neutral constituents in the thermosphere of Venus are being made with a quadrupole mass spectrometer on the Pioneer Venus orbiter. Concentrations of carbon dioxide, carbon monoxide, molecular nitrogen, atomic oxygen, and helium are presented, in addition to an empirical model of the data. The concentrations of the heavy gases, carbon dioxide, carbon monoxide, and molecular nitrogen, rapidly decrease from the evening terminator toward the nightside; the concentration of atomic oxygen remains nearly constant and the helium concentration increases, an indication of a nightside bulge. The kinetic temperature inferred from scale heights drops rapidly from 230 K at the terminator to 130 K at a solar zenith angle of 120°, and to 112 K at the antisolar point.
Molecular Analysis by Mass Spectrometry
Authors: Ligon Woodfin V.
Published: October 2006

New ionization methods combined with powerful analyzers, detectors, and data systems have made mass spectrometry a versatile tool for molecular analysis. Samples consisting of nanogram quantities of hundreds of unique components are routinely analyzed. In favorable cases samples as small as 2.5 × 10
–14
gram and samples with masses of more than 3000 atomic mass units have been successfully examined.
Photooxidation of Anthracene on Atmospheric Particulate Matter
Authors: Fox Marye Anne , Olive Susan
Published: October 2006

Anthracene that has been dispersed into atmospheric particulate matter is photooxidized to an array of products reminiscent of oxidation by singlet oxygen in the solution phase. Photooxidation is a more important degradative pathway under ambient conditions than ozonation. Significant disappearance of anthracene also occurs by pathways not involving oxygenation.
By Dawn's Early Light: Matutinal Mating and Sex Attractants in a Neotropical Mantid
Authors: Robinson Michael H. , Robinson Barbara
Published: October 2006

Females of the neotropical mantis
Acanthops falcata
adopt a special posture at dawn which is maintained for about 20 minutes. During the same period, males fly strongly, even in the absence of females. Our studies show that in this posture females are secreting a pheromone that acts as a sex attractant. All sexual activity in this species normally occurs between dawn and sunrise. It can be triggered by any dark-to-light transition, irrespective of real time. This sexual periodicity is probably an antipredator adaptation
.
Repeated Copulation and Sperm Precedence: Paternity Assurance for a Male Brooding Water Bug
Authors: Smith Robert L.
Published: October 2006

Male giant water bugs (
Abedus herberti
Hidalgo) brood eggs attached to their backs by their mates. Brooders risk being "cuckolded" because females store sperm from previous matings. Males always copulate with females prior to receiving their eggs and mate repeatedly during oviposition. Experiments with a genetic marker reveal almost complete sperm precedence for the last male to mate with a female. The male's behavior therefore assures his paternity of the eggs he broods.
The 46° Halo and Its Arcs
Authors: Greenler Robert G. , Mueller James R. , Hahn Werner , Mallmann A. James
Published: October 2006

Ice crystals in the form of right hexagonal prisms have faces that form 90° prisms. Light rays were traced through these prism faces by computer calculation, and the light patterns that would be produced in the sky for a particular distribution of crystal orientations were simulated. Crystals with random orientations produce a 46° halo. Hexagonal plate crystals with nearly horizontal end faces produce circumzenithal and circumhorizontal arcs. Hexagonal column crystals with horizontal axes produce supralateral and infralateral arcs. Plate crystals spinning about a horizontal axis that is a face diagonal of the crystal produce a series of arcs touching the 46° halo. Each of these effects was simulated for several elevations of the sun.
Fossil Counterparts of Giant Penguins from the North Pacific
Authors: Olson Storrs L. , Hasegawa Yoshikazu
Published: October 2006

New fossils of giant, flightless penguinlike birds have been found in late Oligocene and early Miocene rocks in Japan and in the state of Washington. These birds belong to the order Pelecaniformes, in the extinct family Plotopteridae, previously known by a single fragment of bone from California. Hindlimb and pelvic morphology is most similar to that of Recent anhingas, but the wing is paddlelike and remarkably convergent toward penguins and flightless auks. Both the Plotopteridae and the giant penguins became extinct by the middle Miocene, possibly because of competition from seals and porpoises.
Melting of Helium at Room Temperature and High Pressure
Authors: Besson J. M. , Pinceaux J. P.
Published: October 2006

Helium has been solidified at room temperature. The melting pressure at 24°C is 115 kilobars, in complete agreement with the Simon equation. An original apparatus was developed for this experiment, which allows loading of the cell at room temperature. Applications to various areas of research are suggested.
The "Little Ice Age": Northern Hemisphere Average Observations and Model Calculations
Authors: Robock Alan
Published: October 2006

Numerical energy balance climate model calculations of the average surface temperature of the Northern Hemisphere for the past 400 years are compared with a new reconstruction of the past climate. Forcing with volcanic dust produces the best simulation, whereas expressing the solar constant as a function of the envelope of the sunspot number gives very poor results.
Human Ultrasonic Speech Perception
Authors: Lenhardt Martin L. , Skellett Ruth , Wang Peter , Clarke Alex M.
Published: October 2006

Bone-conducted ultrasonic hearing has been found capable of supporting frequency discrimination and speech detection in normal, older hearing-impaired, and profoundly deaf human subjects. When speech signals were modulated into the ultrasonic range, listening to words resulted in the clear perception of the speech stimuli and not a sense of high-frequency vibration. These data suggest that ultrasonic bone conduction hearing has potential as an alternative communication channel in the rehabilitation of hearing disorders.
Polarization of Fucoid Eggs by a Calcium Ionophore Gradient
Authors: Robinson Kenneth R. , Cone Roger
Published: October 2006

When the eggs of the brown alga
Pelvetia
were grown in a gradient of the calcium ionophore A23187, they tended to form their rhizoidal outgrowths on the sides that were exposed to the higher concentration of ionophore. This result supports the hypothesis that the formation of an intracellular calcium gradient is an essential step in the polarization of these eggs; the rhizoid forms at the pole that has the higher concentration of calcium.
Trapped Radiation Belts of Saturn: First Look
Authors: Fillius W. , Ip W. H. , McIlwain C. E.
Published: October 2006

Pioneer 11 has made the first exploration of the magnetosphere and trapped radiation belts of Saturn. Saturn's magnetosphere is intermediate in size between Earth's and Jupiter's, with trapped particle intensities comparable to Earth's. The outer region of Saturn's magnetosphere contains lower energy radiation and is variable with time; the inner region contains higher energy particles. The pitch angle distributions show a remarkable variety of field-aligned and locally mirroring configurations. The moons and especially the rings of Saturn are effective absorbers of trapped particles; underneath the rings, the trapped radiation is completely absorbed. We confirm the discovery of a new ring, called the F ring, a new division, the Pioneer division, and a moon, called 1979 S 2. The latter has probably been seen from Earth. There may be evidence for more bodies like 1979 S 2, but at this stage the interpretation of the data is ambiguous. Using particle diffusion rates, we estimate that the cross-sectional area of the F ring is > 7 × 10
13
square centimeters and that the opacity is > 10
–5
. Cosmic-ray albedo neutron decay should be looked into as a source of energetic particles in the inner magnetosphere of Saturn.
Ultraviolet Photometer Observations of the Saturnian System
Authors: Judge D. L. , Wu F.-M. , Carlson R. W.
Published: October 2006

Several interesting cloud and atmospheric features of the Saturn system have been observed by the long-wavelength channel of the two-channel ultraviolet photometer aboard the Pioneer Saturn spacecraft. Reported are observations of the most obvious features, including a Titan-associated cloud, a ring cloud, and the variation of atmospheric emission across Saturn's disk. The long-wavelength data for Titan suggest that a cloud of atomic hydrogen extends at least 5 Saturn radii along its orbit and about 1.5 Saturn radii vertically. A ring cloud, thought to be atomic hydrogen, has also been observed by the long-wavelength channel of the photometer; it shows significant enhancement in the vicinity of the B ring. Finally, spatially resolved observations of Saturn's disk show significant latitudinal variation. Possible explanations of the variation include aurora or limb brightening.
Evolutionary Implications of Pliocene Hominid Footprints
Authors: White Tim D.
Published: October 2006

Hominid footprints discovered at the Pliocene (3.6 to 3.8 million years ago) site of Laetoli in northern Tanzania represent the earliest evidence of bipedalism in human evolution. This new evidence emphasizes the mosaic pattern of human evolution.
Evidence for Lignin-Like Constituents in Early Silurian (Llandoverian) Plant Fossils
Authors: Niklas Karl J. , Pratt Lisa M.
Published: October 2006

Chemical evidence is presented with previously reported morphological features for banded-tube cell types in the earliest known plant fossils associated with stream-deposited sediments. Phenolic aldehydes (
p-
hydroxybenzaldehyde, vanillin) and aromatic compounds from pyrolysis (2-methoxy-4-hydroxybenzaldehyde, methylsyringaldehyde) derived from cellular remains are interpreted as evidence for lignin or lignin-like degradation products. The presence of parallel-aligned banded tubes, with annular to spiral thickenings and occasional end walls, in conjunction with lignin-like constituents fulfill most of the morphological and chemical criteria for cell types that could have functioned as water-conducting cells
.
Participation of Male Cytoplasm During Gamete Fusion in an Angiosperm,
Plumbago zeylanica
Authors: Russell Scott D.
Published: October 2006

The embryo sac of
Plumbago
, lacking synergids, reveals an alternative course for pollen tube growth in angiosperms and provides ultrastructural evidence for transmission of sperm cytoplasm into the zygote and endosperm. Study of such evolutionarily reduced female gametophytes may aid in elucidating the structural basis for genetic transmission of plastids and mitochondria in flowering plants.
Territorial Strategies in Ants
Authors: Hölldobler Bert , Lumsden Charles J.
Published: October 2006

Several features in social insects, particularly in ants, make the behavioral organization of territoriality considerably more complex than that of solitary animals. The establishment and maintenance of territories are based on a division of labor and a complex communication system. The analyses of territorial strategies in ants comprise the study of the design and spatiotemporal structure of the territory, as well as the social mechanisms through which the insect society pursues its territorial strategy. The geometric and behavioral organization of the absolute territories of the African weaver ants (
Oecophylla longinoda
) and harvester ants (
Pogonomyrmex
), and of the "spatiotemporal territories" of honey ants (
Myrmecocystus mimicus
) are described, and simple cost-benefit models are developed to illustrate the economic defensibility of each type of territory.
Antbutterflies: Butterflies That Follow Army Ants to Feed on Antbird Droppings
Authors: Ray Thomas S. , Andrews Catherine C.
Published: October 2006

Females of three species of tropical rain forest ithomiine butterflies orient to swarms of army ants (
Eciton burchelli
) and feed on bird droppings found there. The antbirds associated with swarm raids of these ants provide a predictable source of droppings, an otherwise sparsely distributed resource.
Characterization of an Extremely Large, Ligand-Induced Conformational Change in Plasminogen
Authors: Mangel Walter F. , Lin Bohai , Ramakrishnan V.
Published: October 2006

Native human plasminogen has a radius of gyration of 39 angstroms. Upon occupation of a weak lysine binding site, the radius of gyration increases to 56 angstroms, an extremely large ligand-induced conformational change. There are no intermediate conformational states between the closed and open form. The conformational change is not accompanied by a change in secondary structure, hence the closed conformation is formed by interaction between domains that is abolished upon conversion to the open form. This reversible change in conformation, in which the shape of the protein changes from that best described by a prolate ellipsoid to a flexible structure best described by a Debye random coil, is physiologically relevant because a weak lysine binding site regulates the activation of plasminogen.
Calibration of the Beginning of the Age of Mammals in Patagonia
Authors: Marshall Larry G. , Butler Robert F. , Drake Robert E. , Curtis Garniss H.
Published: October 2006

Beds of the Rio Chico Formation containing the earliest known land mammals in Patagonia, southern Argentina, were calibrated by potassium-argon age determinations and paleomagnetic polarity data. The Riochican land mammal age encompasses the middle and late Paleocene and corresponds in time with Torrejonian and Tiffanian land mammal faunas in North America.
The Bridge of Language
Authors: Frye Northrop
Published: October 2006

The elements of human culture, including literature and the sciences, grow out of a basis in social concern. As they develop, their inner structures begin to emerge and those practicing them make discoveries within those structures. When tensions arise with the concerns of society a divided loyalty arises. In the past, social concerns which resisted science or censored literature were usually wrong, but there are very intense concerns today, such as environmental pollution, which appear to be bringing us to a common meeting point.
Encounter with Saturn: Voyager 1 Imaging Science Results
Authors: Smith Bradford A. , Soderblom Laurence , Beebe Reta , Boyce Joseph , Briggs Geoffery , Bunker Anne , Collins Stewart A. , Hansen Candice J. , Johnson Torrence V. , Mitchell Jim L. , Terrile Richard J. , Carr Michael , Cook Allen F. , Cuzzi Jeffrey , Pollack James B. , Danielson G. Edward , Ingersoll Andrew , Davies Merton E. , Hunt Garry E. , Masursky Harold , Shoemaker Eugene , Morrison David , Owen Tobias , Sagan Carl , Veverka Joseph , Strom Robert , Suomi Verner E.
Published: October 2006

As Voyager 1 flew through the Saturn system it returned photographs revealing many new and surprising characteristics of this complicated community of bodies. Saturn's atmosphere has numerous, low-contrast, discrete cloud features and a pattern of circulation significantly different from that of Jupiter. Titan is shrouded in a haze layer that varies in thickness and appearance. Among the icy satellites there is considerable variety in density, albedo, and surface morphology and substantial evidence for endogenic surface modification. Trends in density and crater characteristics are quite unlike those of the Galilean satellites. Small inner satellites, three of which were discovered in Voyager images, interact gravitationally with one another and with the ring particles in ways not observed elsewhere in the solar system. Saturn's broad A, B, and C rings contain hundreds of "ringlets," and in the densest portion of the B ring there are numerous nonaxisymmetric features. The narrow F ring has three components which, in at least one instance, are kinked and crisscrossed. Two rings are observed beyond the F ring, and material is seen between the C ring and the planet.
Infrared Observations of the Saturnian System from Voyager 1
Authors: Hanel R. , Conrath B. , Flasar F. M. , Kunde V. , Maguire W. , Pearl J. , Pirraglia J. , Samuelson R. , Herath L. , Allison M. , Cruikshank D. , Gautier D. , Gierasch P. , Horn L. , Koppany R. , Ponnamperuma C.
Published: October 2006

During the passage of Voyager 1 through the Saturn system, the infrared instrument acquired spectral and radiometric data on Saturn, the rings, and Titan and other satellites. Infrared spectra of Saturn indicate the presence of H
2
, CH
4
, NH
3
, PH
3
, C
2
H
2
, C
2
H
6
, and possibly C
3
H
4
and C
3
H
8
. A hydrogen mole fraction of 0.94 is inferred with an uncertainty of a few percent, implying a depletion of helium in the atmosphere of Saturn relative to that of Jupiter. The atmospheric thermal structure of Saturn shows hemisphere asymmetries that are consistent with a response to the seasonally varying insolation. Extensive small-scale latitudinal structure is also observed. On Titan, positive identifications of infrared spectral features are made for CH
4
, C
2
H
2
, C
2
H
4
, C
2
H
6
, and HCN; tentative identifications are made for C
3
H
4
and C
3
H
8
. The infrared continuum opacity on Titan appears to be quite small between 500 and 600 cm
–1
, implying that the solid surface is a major contributor to the observed emission over this spectral range; between 500 and 200 cm
–1
the opacity increases with decreasing wave number, attaining an optical thickness in excess of 2 at 200 cm
–1
. Temperatures near the 1-millibar level are independent of longitude and local time but show a decrease of ∼ 20 K between the equator and north pole, which suggests a seasonally dependent cyclostrophic zonal flow in the stratosphere of ∼ 100 meters per second. Measurements of the C ring of Saturn yield a temperature of 85 ± 1 K and an infrared optical depth of 0.09 ± 0.01. Radiometer observations of sunlight transmitted through the ring system indicate an optical depth of 10
–1.3 ±0.3
for the Cassini division. A phase integral of 1.02 ± 0.06 is inferred for Rhea, which agrees with values for other icy bodies in the solar system. Rhea eclipse observations indicate the presence of surface materials with both high and low thermal inertias, the former most likely a blocky component and the latter a frost.
Federal Funding of Basic Research: The Red Tape Mill
Authors: Gutowsky H. S.
Published: October 2006

Federal regulations and concerns about accountability for public funds have added greatly to the administrative burden associated with federal support of research at universities. Much of the added burden is viewed as unnecessary and counterproductive by the scientists and administrators who must bear the load. They feel that funds and effort intended for research are being diverted and wasted. The various types of costs are reviewed, including some thoughts as to their origin and estimates of their magnitude. Topics covered include project versus programmatic support, the indirect cost game, accountability, federal regulations, and the bureaucratic syndrome. There are no simple solutions, but several promising initiatives have been taken and more should be forthcoming.
Nuclear Pulse (II): Ensuring Delivery of the Doomsday Signal
Authors: Broad William J.
Published: October 2006

Defense strategists today assume that a single Soviet warhead detonated 200 miles above Nebraska would knock out unprotected communications equipment all across the United States. The reason is electromagnetic pulse (EMP), a by-product of high-altitude nuclear explosions that blankets huge tracts of the earth with peak fields of 50,000 volts per meter.

The first installment of this three-part series described how EMP was discovered and why its potentially chaos-producing effects were overlooked for more than a decade. The second part examines the ongoing debate in the Pentagon over how to cope with the EMP threat. The third part will discuss questions EMP raises about waging a limited nuclear war.
Chemoautotrophic Potential of the Hydrothermal Vent Tube Worm,
Riftia pachyptila
Jones (Vestimentifera)
Authors: Felbeck Horst
Published: October 2006

Trophosome tissue of the hydrothermal vent tube worm,
Riftia pachyptila
(Vestimentifera), contains high activities of several enzymes associated with chemoautotrophic existence. Enzymes catalyzing synthesis of adenosine triphosphate using energy contained in sulfur compounds such as hydrogen sulfide, and two diagnostic enzymes of the Calvin-Benson cycle of carbon dioxide fixation, ribulosebisphosphate carboxylase and ribulose 5-phosphate kinase, are present at high levels in trophosome, but are absent in muscle. These data are consistent with an autotrophic mode of nutrition for this worm, which lives in hydrogen sulfide-rich waters and lacks a mouth and digestive system.
Achievement Test Scores in Mathematics and Science
Authors: Jones Lyle V.
Published: October 2006

Average achievement test scores of the nation's youth in mathematics and science have declined rather steadily since the early 1960's, and this decline is more marked in the higher grades. The average test scores in mathematics and science of high school seniors who have intended to go to college and major in those fields, however, have been quite stable. These findings may have implications for educational policy.
North Atlantic Subtropical Gyre: SOFAR Floats Tracked by Moored Listening Stations
Authors: Richardson P. L. , Price J. F. , Owens W. B. , Schmitz W. J. , Rossby H. T. , Bradley A. M. , Valdes J. R. , Webb D. C.
Published: October 2006

In 1980, SOFAR (sound fixing and ranging) floats were tracked acoustically in the western North Atlantic entirely by means of moored autonomous listening stations. During a 5-month period 17 float trajectories were obtained in the eastern (45° to 65°W) Gulf Stream and subtropical gyre interior at depths of 700 and 2000 meters. These mid-depth trajectories suggest a time-varying Gulf Stream with instances of both a narrow, swift, westward recirculation south of the stream and a northeastward penetration into the Newfoundland Basin. A hundredfold increase of eddy kinetic energy was observed at 2000 meters from the gyre interior (south of 30°N) to the Gulf Stream.
Circular Feature Among Dunes of the Great Sand Sea, Egypt
Authors: El-Baz Farouk
Published: October 2006

A circular crater, about 4 kilometers in diameter and located at 24.2°N, 26.4°E, was discovered in Landsat images among the linear dunes of the Great Sand Sea, Egypt. The crater has a sharp and crenulated rim crest, a terraced wall, a discontinuous inner structure (approximately 1.6 kilometers in diameter), and a few rim blocks. Its morphological and morphometric characteristics are similar to those of meteorite impact craters and other circular structures on the moon and the terrestrial planets. Because of its interaction with windblown sand, it is particularly comparable with craters on Mars.
Role of Golgi Apparatus in Sorogenesis by the Cellular Slime Mold
Fonticula alba
Authors: Deasey Mary C. , Olive Lindsay S.
Published: October 2006

Aggregating cells of the cellular slime mold
Fonticula alba
form a volcano-shaped fruiting structure which at maturity bears its spores apically in a globose mucous mass. Numerous dictyosomes forming in the sorogenic cells are involved in the accumulation and deposition of stalk material.
Methylation of Trimethyltin Compounds by Estuarine Sediments
Authors: Guard Harold E. , Cobet Andre B. , Coleman W. M.
Published: October 2006

Both biologically active and autoclaved sediments convert trimethyltin hydroxide to the volatile tetramethyltin. Larger amounts of tetramethyltin were formed in the bioactive sediments than in the sterile sediments. No volatile tin compounds were detected in the absence of trimethyltin hydroxide or from trimethyltin hydroxide in seawater or in seawater containing bentonite. The formation of tetramethyltin is slow, taking over 80 days at 16°C to reach a maximum. The extent of conversion, although significant, is not extensive. The formation of tetramethyltin occurs in estuarine sediments by both abiotic and biologically enhanced pathways. A redistribution mechanism accounts for at least the abiotic pathway and possibly both formation pathways.
Origin of Corn: Pollen Evidence
Authors: Beadle George W.
Published: October 2006

The origin of Indian corn remains controversial. Its closest wild relative is teosinte, with which it hybridizes freely to produce fertile progeny. Teosinte ears are smaller and simpler than those of corn. Searches for a more likely living ancestor have failed, but nine of its assumed pollen grains have been recovered in deep drill-core samples obtained from a stratum of soil under Mexico City, which is believed to antedate man in the Western Hemisphere. These nine largest grains are indistinguishable from pollen of modern corn. It has been assumed to be that of a postulated wild corn other than that of teosinte, but this does not account for the possibility that the pollen grains are those of a tetraploid teosinte-producing pollen with two sets of chromosomes. This likelihood has been examined by treating modern teosinte plants with colchicine, which induces tetraploidy. The result has been many teosinte pollen grains indistinguishable in size from modern corn. In interpreting this outcome it is important also to know that heat treatment of corn and other plants induces polyploidy, and that the deep drill-core pollen was recovered in a stratum of volcanic clay indicating the high temperature known to favor doubling of corn pollen volumes.
An Essential Signaling Role for the m
3
G Cap in the Transport of U1 snRNP to the Nucleus
Authors: Fischer Utz , Lührmann Reinhard
Published: October 2006

The major small nuclear ribonucleoprotein particles (snRNPs) U1, U2, U4 + U6, and U5 have to be transported from the cytoplasm, where they are synthesized, to the nucleus, where they splice pre-messenger RNAs. Since the free core snRNP proteins in the cytoplasm do not enter the nucleus on their own, the nuclear location signal must either reside on the snRNA or be created as a result of snRNA-protein interaction. Here the involvement by the 5′-terminal cap of snRNA molecules in the nucleo-cytoplasmic transport of UsnRNPs has been studied by microinjection of synthetic U1 RNA molecules into frog oocytes; the U1 RNA bore either the normal cap (m
3
G) or a chemical derivative. Antibodies in the cytoplasm against the m
3
G cap inhibited the nuclear uptake of U1 snRNP. U1 RNA that was uncapped or contained an unnatural ApppG cap did not enter the nucleus, even though it carried a normal complement of protein molecules. When the ribose ring of the m
3
G cap was oxidized with periodate, nuclear transport of U1 snRNPs was severely inhibited. Finally, microinjection of m
3
G cap alone (but not m
7
G cap) into oocytes severely inhibited the transport of U1 snRNPs to the nucleus. These data suggest that one step in the nuclear uptake of U1 snRNPs involves the m
3
G cap structure.
A Plant Leucine Zipper Protein That Recognizes an Abscisic Acid Response Element
Authors: Guiltinan Mark J. , Marcotte William R. , Quatrano Ralph S.
Published: October 2006

The mechanism by which phytohormones, like abscisic acid (ABA), regulate gene expression is unknown. An activity in nuclear extracts that interacts with the ABA response element (ABRE) from the 5′ regulatory region of the wheat
Em
gene was identified. A complementary DNA clone was isolated whose product is a DNA binding protein (EmBP-1) that interacts specifically with an 8-base pair (bp) sequence (CACGTGGC) in the ABRE. A 2-bp mutation in this sequence prevented binding of EmBP-1. The same mutation reduced the ability of the ABRE to confer ABA responsiveness on a viral promoter in a transient assay. The 8-bp EmBP-1 target sequence was found to be conserved in several other ABA-responsive promoters and in promoters from plants that respond to signals other than ABA. Similar sequences are found in promoters from mammals, yeast, and in the major late promoter of adenovirus. The deduced amino acid sequence of EmBP-1 contains conserved basic and leucine zipper domains found in transcription factors in plants, yeast, and mammals. EmBP-1 may be a member of a highly conserved family of proteins that recognize a core sequence found in the regulatory regions of various genes that are integrated into a number of different response pathways.
Sequence Requirements for Coiled-Coils: Analysis with λ Repressor-GCN4 Leucine Zipper Fusions
Authors: Hu James C. , O'Shea Erin K. , Kim Peter S. , Sauer Robert T.
Published: October 2006

A genetic system was developed in
Escherichia coli
to study leucine zippers with the amino-terminal domain of bacteriophage λ repressor as a reporter for dimerization. This system was used to analyze the importance of the amino acid side chains at eight positions that form the hydrophobic interface of the leucine zipper dimer from the yeast transcriptional activator, GCN4. When single amino acid substitutions were analyzed, most functional variants contained hydrophobic residues at the dimer interface, while most nonfunctional sequence variants contained strongly polar or helix-breaking residues. In multiple randomization experiments, however, many combinations of hydrophobic residues were found to be nonfunctional, and leucines in the heptad repeat were shown to have a special function in leucine zipper dimerization.
Occultation by a Possible Third Satellite of Neptune
Authors: Reitsema H. J. , Hubbard W. B. , Lebofsky L. A. , Tholen D. J.
Published: October 2006

The 24 May 1981 close approach of Neptune to an uncataloged star was photoelectrically monitored from two observatories separated by 6 kilometers parallel to the occultation track. An 8.1-second drop in signal, recorded simultaneously at both sites, is interpreted as resulting from the passage of a third satellite of Neptune in front of the star. From the duration of the event, the derived minimum diameter for an object sharing Neptune's motion is 180 kilometers. If the object was in Neptune's equatorial plane and there are no significant errors in the prediction ephemeris, the object was located at a distance of 3 Neptune radii from Neptune's center.
Photopolarimetry from Voyager 2; Preliminary Results on Saturn, Titan, and the Rings
Authors: Lane Arthur L. , Hord Charles W. , West Robert A. , Esposito Larry W. , Coffeen David L. , Sato Makiko , Simmons Karen E. , Pomphrey Richard B. , Morris Richard B.
Published: October 2006

The Voyager 2 photopolarimeter was reprogrammed prior to the August 1981 Saturn encounter to perform orthogonal-polarization, two-color measurements on Saturn, Titan, and the rings. Saturn's atmosphere has ultraviolet limb brightening in the mid-latitudes and pronounced polar darkening north of 65°N. Titan's opaque atmosphere shows strong positive polarization at all phase angles (2.7° to 154°), and no single-size spherical particle model appears to fit the data. A single radial stellar occultation of the darkened, shadowed rings indicated a ring thickness of less than 200 meters at several locations and clear evidence for density waves caused by satellite resonances. Multiple, very narrow strands of material were found in the Encke division and within the brightest single strand of the F ring.
University Role in the Computer Age
Authors: Linvill John G.
Published: October 2006

Realization of the potential of computer electronics for enhanced human productivity and economic impact depends strongly on the university. New manpower and continuing education for the existing work force as well as new ideas for research and development will come from that sector. University-industry coupling offers mutual advantages to the partners and benefits to the nation in the computer age.
Business Use of Satellite Communications
Authors: Edelson Burton I. , Cooper Robert S.
Published: October 2006

The development of satellite communications over the past two decades has been very rapid. At the same time, space and electronics technologies have progressed sufficiently to allow satellite systems to keep pace with user requirements and to expand in several dimensions, including capacity, coverage, performance, reliability, and variety of services. The principal services provided by satellite systems have been long-distance trunks for telephone circuits and television program distribution. Recently, data transmission and network services have been added to meet emerging requirements for "office of the future" and other business applications. Data services are now expected to be the most rapidly expanding element of satellite communications.
Methylation of Tin by Estuarine Microorganisms
Authors: Hallas L. E. , Means J. C. , Cooney J. J.
Published: October 2006

Mixed inoculums of microorganisms from Chesapeake Bay sediments transformed inorganic tin (SnCl
4
⋅ 5H
2
O) to organotin compounds. Dimethyltin and trimethyltin species were identified as products by gas chromatography—mass spectrometry. Methylated tin species were not observed in sterile controls or in poisoned controls. Thus, estuarine microorganisms have the potential for transforming tin to toxic organotins and for mobilizing tin in the ecosystem.
Cyanobacterial Blooms: Carbon and Nitrogen Limitation Have Opposite Effects on the Buoyancy of
Oscillatoria
Authors: Klemer A. R. , Feuillade J. , Feuillade M.
Published: October 2006

Gas vacuolation in
Oscillatoria rubescens
decreased with increased nitrogen limitation and increased with transitions from nitrogen to inorganic carbon limitation. Gas vacuoles consist of protein vesicles that can accumulate in carbon-limited but not in unenriched nitrogen-limited cells. Nitrogen limitation is a factor in the formation of deep population maxima; carbon limitation can promote surface blooms.