bluuebunny/crossref_metadata_2025 huggingface dataset:
A Terminal Mesozoic "Greenhouse": Lessons from the Past
Authors: McLean Dewey M.
Published: October 2006

The late Mesozoic rock and life records implicate short-term (up to 10
5
to 10
6
years) global warming resulting from carbon dioxide—induced "greenhouse" conditions in the late Maestrichtian extinctions that terminated the Mesozoic Era. Oxygen isotope data from marine microfossils suggest late Mesozoic climatic cooling into middle Maestrichtian, and warming thereafter into the Cenozoic. Animals adapting to climatic cooling could not adapt to sudden warming. Small calcareous marine organisms would have suffered solution effects of carbon dioxide—enriched waters; animals dependent upon them for food would also have been affected. The widespread terrestrial tropical floras would likely not have reflected effects of a slight climatic warming. In late Mesozoic, the deep oceanic waters may have been triggered into releasing vast amounts of carbon dioxide into the atmosphere in a chain reaction of climatic warming and carbon dioxide expulsion. These conditions may be duplicated by human combustion of the fossil fuels and by forest clearing.
Thermal Sensitivity in Lichens
Authors: MacFarlane J. D. , Kershaw K. A.
Published: October 2006

Lichens are believed to be extremely resistant to high-temperature stress when desiccated. Results from a reexamination of this concept indicate that some air-dry lichen thalli can be extremely sensitive to even moderate levels of heat stress whereas others exhibit a considerable degree of heat resistance. These differential levels of thermal resistance correlate exactly with the ecology of these populations.
The Paredón, Mexico, Obsidian Source and Early Formative Exchange
Authors: Charlton Thomas H. , Grove David C. , Hopke Philip K.
Published: October 2006

In 1975, archeological surface surveys of trade routes located again a pre-Hispanic obsidian source in central Mexico first reported in 1902. Initial trace element studies of the Paredón source through an analysis by neutron activation have been compared with similar studies of the obsidian found at Chalcatzingo 150 kilometers from the source. These comparisons indicate that obsidian from Paredón, rather than Otumba, was of primary importance during the Early Formative in central Mexico.
Chemoreceptors in Lepidoptera: Stereochemical Differentiation of Dual Receptors for an Achiral Pheromone
Authors: Chapman Orville L. , Klun Jerome A. , Mattes K. C. , Sheridan Robert S. , Maini Stefano
Published: October 2006

The racemate and optically pure enantiomers of 9-(2-cyclopenten-1-yl)nonyl acetate have been synthesized and shown to mimic certain biological properties of (
Z
)-11-tetradecenyl acetate. European corn borers and red-banded leaf rollers respond differently to the racemate and to the enantiomers in precopulatory behavior bioassay. The responses demonstrate the presence of two stereospecific chemoreceptors, show the chiral character of these receptors, and define the conformation of carbon atoms 10 to 14 of (
Z
)-11-tetradecenyl acetate in these receptors.
Tree Ring Evidence for Chronic Insect Suppression of Productivity in Subalpine
Eucalyptus
Authors: Morrow P. A. , LaMarche Valmore C.
Published: October 2006

Experimental reduction of insect grazing pressures suggests that long-term, continuous feeding by phytophagous insects has severely depressed growth and productivity of subalpine
Eucalyptus
trees (measured by annual ring growth) for at least 25 years.
Free Radical Increases in Cancer: Evidence That There Is Not a Real Increase
Authors: Swartz Harold M. , Gutierrez Peter L.
Published: October 2006

The controversial finding of an increase in free radicals with the development of cancer was restudied with Walker 256 carcinosarcoma cells. It was confirmed that such an increase appears to occur, but it was also demonstrated that it is not a real increase. With growth of the tumor, the electron spin resonance lines for lyophilized samples became narrower, resulting in an increase in peak-to-peak height measurements, but there was no change in the total number of spins. The signals for lyophilized tumor samples were different from those for the same samples before lyophilization. Changes in line shape indicated that lyophilized tumor samples contain a different mixture of radicals than lyophilized samples of normal tissue.
Cocaine Addiction: Psychology and Neurophysiology
Authors: Gawin Frank H.
Published: October 2006

Cocaine was considered incapable of producing dependence in 1980 but was recently proclaimed the drug of greatest national health concern. Recent clinical and preclinical investigations demonstrate that cocaine produces unique abuse and withdrawal patterns that differ from those of other major abused drugs and suggest that long-term cocaine abuse produces neurophysiological alterations in specific systems in the central nervous system that regulate the capacity to experience pleasure. It will be necessary to develop clinically pertinent research models before these findings can be considered definitive, but these evolving ideas have already led to applications of promising experimental treatments for cocaine abuse.
Mediation of Responses to Calcium in Taste Cells by Modulation of a Potassium Conductance
Authors: Bigiani Albertino R. , Roper Stephen D.
Published: October 2006

Calcium salts are strong taste stimuli in vertebrate animals. However, the chemosensory transduction mechanisms for calcium are not known. In taste buds of
Necturus maculosus
(mud puppy), calcium evokes depolarizing receptor potentials by acting extracellularly on the apical ends of taste cells to block a resting potassium conductance. Therefore, divalent cations elicit receptor potentials in taste cells by modulating a potassium conductance rather than by permeating the cell membrane, the mechanism utilized by monovalent cations such as sodium and potassium ions.
North American Pleistocene Stages Reconsidered in Light of Probable Pliocene-Pleistocene Continental Glaciation
Authors: Boellstorff John
Published: October 2006

Confusion due to the conceptual usage of classic North American Pleistocene stage terms indicates the need for a new or revised terminology. The Pliocene-Pleistocene boundary has tentatively been dated about 2.5 ± 0.1 × 10
6
years. Glacial deposits in the central United States older than about 2.2 × 10
6
years may span that boundary.
Synthesis of Isocyanic Acid from Nitric Oxide over Palladium and Iridium Catalysts
Authors: Voorhoeve R. J. H. , Trimble L. E.
Published: October 2006

A novel and convenient synthesis of isocyanic acid (HNCO) and its trimer isocyanuric acid has been obtained by the conversion of nitric oxide (NO). Nitric oxide, carbon monoxide, and hydrogen mixed in helium at the level of 0.3 to 5 percent reacted over iridium and palladium catalysts at 280° to 450°C to form HNCO in 60 to 75 percent yield. Major side products were ammonium cyanate at low temperature and ammonia or nitrogen at high temperature. Total conversion of nitrogen from NO to NCO reached 73 percent over palladium and 86 percent over iridium.
Nuclear Power: A Balanced Approach
Authors: Rickard Corwin L. , Dahlberg Richard C.
Published: October 2006

A proposed technological approach to meeting recognized nuclear power needs is a symbiotic combination of breeders and advanced converter reactors. Breeders, situated in secured areas, would be fueled with and self-sufficient in plutonium. The excess fuel produced in the breeder would be uranium-233, sufficient in quantity to supply several advanced converters located near load centers. This approach is suggested as a balanced way to meet important criteria applicable to the continued development of nuclear power.
Planck's Principle
Authors: Hull David L. , Tessner Peter D. , Diamond Arthur M.
Published: October 2006

Two views about the Darwinian revolution are tested: that nearly all scientists in Great Britain had been converted to a belief in the evolution of species within 10 years after the publication of the
Origin of Species
, and that younger scientists were converted much more rapidly than older scientists. Both views are shown to be less than accurate.
Acoustic Detection of Cosmic-Ray Air Showers
Authors: Barrett W. Louis
Published: October 2006

The signal strength, bandwidth, and detection range of acoustic pulses generated by cosmic-ray air showers striking a water surface are calculated. These signals are strong enough to be audible to a submerged swimmer. The phenomena may be useful for studying very-high-energy cosmic rays and may help answer the important question of whether the origin of cosmic rays is extragalactic or galactic.
A New Tax on Gasoline: Estimating Its Effect on Consumption
Authors: Schneider Alan M.
Published: October 2006

Based on extrapolation of a recent estimate of the elasticity of demand for gasoline, it is concluded that a tax of 5 cents per gallon per year over the period 1979 to 1988 can be expected to produce significant reductions in gasoline consumption, contrary to widely expressed opinions.
Cultural Transmission of Enemy Recognition: One Function of Mobbing
Authors: Curio E. , Ernst U. , Vieth W.
Published: October 2006

There are at least ten suggested hypotheses for the function of mobbing predators by fish, birds, and mammals. Experiments with captive European blackbirds support one of these—the "cultural transmission hypothesis." Perceiving a mobbing conspecific together with a novel, harmless bird induced blackbirds to mob the innocuous object. The mobbing response persisted during subsequent presentations of the novel bird alone, which was more effectively conditioned than an artificial control object. Enemy recognition could be culturally transmitted along a chain of at least six individuals.
Homoeologous Chromosome Pairing: Frequency Differences in Inbred and Intraspecific Hybrid Polyploid Ferns
Authors: Hickok L. G.
Published: October 2006

The homosporous fern
Ceratopteris thalictroides
(Parkeriaceae) has evolved a polyploid genetic system that serves to store and release genetic variability in spite of self-fertilization and Mendelian homozygosity. This is demonstrated by the segregation of a gametophyte mutant within two inbred tetraploid lines and in their intraspecific hybrid. The segregation behavior can be explained by a model involving a duplicated locus and regular homoeologous chromosome pairing. Homoeologous pairing occurs at low levels in the inbred lines and at a high level in the hybrid, indicating intraspecific differences in chromosome pairing affinities.
Energy Resources Available to the United States, 1985 to 2000
Authors: Hayes Earl T.
Published: October 2006

Energy and the gross national product have grown hand in hand at 3 to 3½ percent a year for almost 40 years. Our energy growth is slowing down and will essentially level off in the 1990's. Our production of oil and gas passed a peak in the early 1970's, and there is no resource base to justify predictions of increased yields. Coal is the only fossil fuel capable of increased production. There are serious doubts that our uranium resources can support a large light-water reactor program. Finding rates for petroleum, natural gas, and uranium are less than half of what they were 20 years ago.
Carbonate Inhibits the Crystallization of Aluminum Hydroxide in Bauxite
Authors: Bárdossy G. , White Joe L.
Published: October 2006

Although the role of anions such as nitrate, chloride, and sulfate in inhibiting the crystallization of aluminum hydroxide in soils and geological deposits is generally accepted, the dramatic effect of the carbonate ion in maintaining aluminum hydroxide gel in the amorphous form has been overlooked by most earth scientists. Examination of bauxite occurrences suggests that the inhibiting effect of carbonate is quite apparent in the smaller grain size of gibbsite in karstic bauxite deposits as compared to that in lateritic bauxite. Scarbröite, a crystalline aluminum hydroxy carbonate, has been observed in rare instances. It is suggested that the highly reactive carbonate-containing aluminum hydroxide gels used as pharmaceutical antacids are amorphous or poorly crystalline forms of scarbröite. The effect of the sulfate anion is also apparent in certain bauxite deposits where dissolution of gibbsite by sulfuric acid has resulted from the oxidation of pyrite, with subsequent reprecipitation of gibbsite.
Sodium Requirement for the Positive Inotropic Action of Isoproterenol on Guinea Pig Atria
Authors: Linden Joel , Brooker Gary
Published: October 2006

Isoproterenol does not elicit its characteristic positive inotropic action in contracting guinea pig atria suspended in sodium-free media. However, the ability of isoproterenol to decrease the time to peak tension development during an individual contraction cycle is still present in sodium-free solutions. Removal of sodium diminished but did not eliminate the tissues' ability to elevate adenosine 3′,5′-monophosphate in response to isoproterenol. The striking absence of an inotropic action by isoproterenol on atria in sodium-free media suggests that sodium (and possibly a sodium-calcium exchange across the sarcolemma) plays an important role in the inotropic action of catecholamines.
Serum Lipoprotein Concentrations in Cystic Fibrosis
Authors: Vaughan W. J. , Lindgren F. T. , Whalen J. B. , Abraham S.
Published: October 2006

Two major classes of lipoproteins, low density and high density, are decreased in the serum of patients with cystic fibrosis; major apoproteins are also decreased. Since essential fatty acids and certain fat-soluble vitamins depend on lipoproteins for transport in the serum, knowledge of lipoprotein levels in cystic fibrosis patients could prove valuable in understanding (i) the basis for the abnormally low serum levels of these fatty acids and vitamins and (ii) the effects of therapies involving these molecules.
Site-Specific Recombination Between Homologous Chromosomes in
Drosophila
Authors: Golic Kent G.
Published: October 2006

The ability to mark a cell and its descendants genetically so that the resulting cell clone can be distinguished from neighboring cells facilitates studies in animal biology and development. A method of generating clones by inducing homologous mitotic recombination in
Drosophila
with a site-specific yeast recombinase is described. This method allows for frequent mosaicism after mitotic exchange is induced at predefined sites in the genome.
Crystalline Ribulose 1,5-Bisphosphate Carboxylase-Oxygenase from Spinach
Authors: Johal Sarjit , Bourque Don P.
Published: October 2006

Spinach fraction I protein (ribulose 1,5-bisphosphate carboxylase-oxygenase, E.C. 4.1.1.39) was crystallized on both an analytical and a preparative scale by vapor diffusion with polyethylene glycol (molecular weight, 6000) used as the precipitant. The identity of the crystalline material with fraction I protein was shown by gel electrophoresis in the presence of sodium dodecyl sulfate and immunological properties. The carboxylase and oxygenase activities copurify during crystallization, and the crystalline enzyme lacks copper and iron.
Vapor Phase Explosions: Elementary Detonations?
Authors: Fowles G. R.
Published: October 2006

Although liquid-vapor explosions are widely observed, there is no established explanation for their initiation and propagation. Thermodynamics admits the possibility that superheated liquids can support detonations analogous to those that occur in chemical explosives. For liquid methane superheated 50 K above its boiling point at 1 atmosphere, the energy of explosion is 2 to 3 percent of that of TNT.
Venice: Sea-Lagoon Exchange in a Modified Tide Regime
Authors: Vittori Ottavio , Tampieri Francesco
Published: October 2006

Salinity and tide heights recorded for a month at
P
0
, a point in the northern section of the Venetian lagoon, are the basic experimental data used to construct a numerical model which describes the salinity variations at
P
0
as a function of the tides measured at the Lido entrance. The time variation of the salinity pattern is interpreted in terms of a lagoon system in which a freshwater source of constant intensity is in a quasi-steady equilibrium with a tide-modulated sink. The mean residence time of a contaminant in this simulated lagoon is predicted from the change in the salinity pattern due to a reduction in the entrance size.
γ-Aminobutyric Acid, a Neurotransmitter, Induces Planktonic Abalone Larvae to Settle and Begin Metamorphosis
Authors: Morse Daniel E. , Hooker Neal , Duncan Helen , Jensen Lloyd
Published: October 2006

γ-Aminobutyric acid (a simple amino acid and potent neurotransmitter in human brain and other tissues of higher animals) and certain of its congeners rapidly and synchronously induce planktonic larvae of the red abalone,
Haliotis rufescens
to settle and commence behavioral and developmental metamorphosis. These naturally occurring inducers of algal origin apparently are responsible, in part, for the substrate-specific recruitment, induction of settling, and the onset of metamorphosis of abalone and other planktonic larvae upon specific algae which provide naturally favorable habitats for the young of these species in coastal waters. These observations provide a convenient experimental model for further analysis of the basic molecular mechanisms by which environmental and endogenous factors control the recruitment and development of planktonic larvae. Halogenated organic pesticides significantly interfere with larval settling, as quantified in a new bioassay based upon these findings.
Forests in the Long Sweep of American History
Authors: Clawson Marion
Published: October 2006

The role of forests in the American society and economy has changed greatly over the past 200 years, as is evidenced by data on acreage in forests, on volume of standing timber, on amount of annual wood growth, on amounts and form of wood utilization, and on prices for forest products. The two most dramatic facts in a long history of forest utilization have been the near fourfold increase in annual wood growth in the past 60 years and the persistent and major underestimate by the U.S. Forest Service of the wood production potential of American forests.
Seasat Scatterometer: Results of the Gulf of Alaska Workshop
Authors: Jones W. Linwood , Black P. G. , Boggs D. M. , Bracalente E. M. , Brown R. A. , Dome G. , Ernst J. A. , Halberstam I. M. , Overland J. E. , Peteherych S. , Pierson W. J. , Wentz F. J. , Woiceshyn P. M. , Wurtele M. G.
Published: October 2006

The Seasat microwave scatterometer was designed to measure, globally and in nearly all weather, wind speed to an accuracy of ± 2 meters per second and wind direction to ± 20° in two swaths 500 kilometers wide on either side of the spacecraft. For two operating modes in rain-free conditions, a limited number of comparisons to high-quality surface truth indicates that these specifications may have been met.
Seasat Synthetic Aperture Radar: Ocean Wave Detection Capabilities
Authors: Gonzalez F. I. , Beal R. C. , Brown W. E. , DeLeonibus P. S. , Sherman J. W. , Gower J. F. R. , Lichy D. , Ross D. B. , Rufenach C. L. , Shuchman R. A.
Published: October 2006

A preliminary assessment has been made of the capability of the Seasat synthetic aperture radar to detect ocean waves. Comparison with surface and aircraft measurements from five passes of the satellite over the Gulf of Alaska indicates agreement to within about ± 15 percent in wavelength and about ± 25° in wave direction. These results apply to waves 100 to 250 meters in length, propagating in a direction predominantly across the satellite track, in sea states with significant wave height (H
1/3
) in a range of 2 to 3.5 meters.
Specific-Opiate-Induced Depression of Transmitter Release from Dorsal Root Ganglion Cells in Culture
Authors: Macdonald Robert L. , Nelson Phillip G.
Published: October 2006

The opiate etorphine depresses monosynaptic excitatory postsynaptic potentials (EPSP's) elicited in spinal cord cells by activation of dorsal root ganglion cells in murine neuronal cell culture. The depression is reversed by naloxone. Statistical analysis of the synaptic responses reveals that the opiate reduces EPSP quantal content at this synapse without altering quantal size. Therefore, the opiate action is presynaptic and affects transmitter release rather than postsynaptic responsiveness.
Potential of Visual Cortex to Develop an Array of Functional Units Unique to Somatosensory Cortex
Authors: Schlaggar Bradley L. , O'Leary Dennis D. M.
Published: October 2006

The identification of specialized areas in the mammalian neocortex, such as the primary visual or somatosensory cortex, is based on distinctions in architectural and functional features. The extent to which certain features that distinguish neocortical areas in rats are prespecified or emerge as a result of epigenetic interactions was investigated. Late embryonic visual cortex transplanted to neonatal somatosensory cortex was later assayed for "barrels," anatomically identified functional units unique to somatosensory cortex, and for boundaries of glycoconjugated molecules associated with barrels. Barrels and boundaries form in transplanted visual cortex and are organized in an array that resembles the pattern in the normal barrelfield. These findings show that different regions of the developing neocortex have similar potentials to differentiate features that distinguish neocortical areas and contribute to their unique functional organizations.
Prostaglandin E
1
Inhibits Platelet Aggregation by a Pathway Independent of Adenosine 3′,5′-Monophosphate
Authors: Sinha Asru K. , Colman Robert W.
Published: October 2006

Aggregation of human blood platelets induced by adenosine diphosphate or
l
-epinephrine was inhibited when the platelets were suspended in plasma which had been previously exposed to an insolubilized ω-aminohexylagarose derivative of prostaglandin E
1
. This decrease of platelet aggregation was not accompanied by a change in the concentration of adenosine 3′,5′-monophosphate (cyclic AMP) in platelets. The results demonstrate the existence of an alternative pathway independent of cyclic AMP for the inhibition of platelet aggregation by plasma.
Absorption of Whistler Mode Waves in the Ionosphere of Venus
Authors: Taylor W. W. L. , Scarf F. L. , Russell C. T. , Brace L. H.
Published: October 2006

It is shown that whistler mode waves from the ionosheath of Venus are absorbed by Landau damping at the dayside ionosphere boundary. This process heats the ionospheric electrons and it may provide an important energy input into the dayside ionosphere. Cyclotron damping of the waves does not occur in the same region. However, Landau damping of ionosheath waves is apparently not an important energy source in the nightside ionosphere. Impulsive events in the nightside ionosphere seem to fall into two classes: (i) lightning signals (near periapsis) and (ii) noise, which may be caused by gradient or current instabilities.
Gamma-Ray Burst Observations by Pioneer Venus Orbiter
Authors: Evans W. D. , Glore J. P. , Klebesadel R. W. , Laros J. G. , Tech E. R. , Spalding R. E.
Published: October 2006

The Pioneer Venus orbiter gamma burst detector is an astrophysics experiment for monitoring cosmic gamma-ray bursts. It is included in this planetary mission to provide a long baseline for accurately locating the sources of these bursts in order to identify them with specific astronomical objects. Responses to 14 gammaray burst events were examined; these events were verified from data acquired by other systems. Preliminary locations are proposed for three events, based on data from the Pioneer Venus orbiter, ISEE C, and Vela spacecraft. These locations will be improved, and additional locations will be determined by including in the analyses data from Helios B and the Russian Venera 11, Venera 12, and Prognoz 7 spacecraft.
Absorption of Sunlight in the Atmosphere of Venus
Authors: Tomasko Martin G. , Doose Lyn R. , Smith Peter H.
Published: October 2006

In this report the fluxes measured by the solar flux radiometer (LSFR) of the Pioneer Venus large probe are compared with calculations for model atmospheres. If the large particles of the middle and lower clouds are assumed to be sulfur, strong, short-wavelength absorption results in a net flux profile significantly different from the LSFR net flux measurements. Models in which the smallest particles are assumed to be sulfur gave flux profiles consistent with the measurements if an additional source of absorption is included in the upper cloud. The narrowband data from 0.590 to 0.665 micrometer indicate an absorption optical depth of about 0.05 below the cloud bottom. The broadband data imply that either this absorption extends over a considerable wavelength interval (as might be the case for dust) or that a very strong absorption band lies on one side of the narrowband filter (as suggested by early Venera 11 and Venera 12 reports). Thermal balance calculations based on the measured visible fluxes indicate high surface temperature for reasonable assumptions of cloud opacity and water vapor abundance. The lapse rate becomes convective within the middle cloud. For water mixing ratios of 2.0 × 10
–4
below the clouds we find a subadiabatic region extending from the cloud bottom to altitudes near 35 kilometers.
Prevention of Fungal Infection of Plants by Specific Inhibition of Cutinase
Authors: Maiti I. B. , Kolattukudy P. E.
Published: October 2006

Specific antibodies prepared against cutinase from
Fusarium solani pisi
and diisopropylfluorophosphate, a potent inhibitor of this enzyme, prevented infection of the host (pea epicotyl) by this organism, without affecting the viability of the spores. This finding shows that enzymatic penetration of cuticle is involved in pathogenesis.
Cell-Free Nitrogenase and Hydrogenase from Actinorhizal Root Nodules
Authors: Benson David R. , Arp Daniel J. , Burris R. H.
Published: October 2006

Field-grown alder (
Alnus glutinosa
) root nodules were disrupted in liquid nitrogen to release the actinomycete endophytes. The endophytes were broken by mild sonic oscillation and yielded a cell-free nitrogenase preparation capable of reducing acetylene and protons. In addition, the preparation carried a cell-free uptake hydrogenase.
Tomatine and Parasitic Wasps: Potential Incompatibility of Plant Antibiosis with Biological Control
Authors: Campbell Bruce C. , Duffey Sean S.
Published: October 2006

α-Tomatine, an alkaloid in tomato plants, is toxic to an endoparasite of a major lepidopterous pest of tomatoes. The parasite acquires the alkaloid from its host after the host ingests the alkaloid. This form of interaction creates a potential dilemma to controlling herbivorous pests through chemical antibiosis in plants.
Sexual Difference in Pattern of Hormone Accumulation in the Brain of a Songbird
Authors: Arnold Arthur P. , Saltiel Albert
Published: October 2006

After adult zebra finches (
Poephila guttata
) received injections of tritiated testosterone, fewer hormone-concentrating cells were found in females than in males in two brain regions involved in song: hyperstriatum ventrale pars caudale and magnocellular nucleus of the anterior neostriatum. In some other regions, no sexual difference was detected. It is, therefore, possible that sex differences in the sensitivity of specific neural populations to hormones underlie the striking anatomical dimorphism observed in neural regions controlling song.
Oxidant Effects on Californian Coastal Sage Scrub
Authors: Westman Walter E.
Published: October 2006

Causes for the reduced cover of native species of coastal sage scrub in certain southern Californian sites were sought among 43 habitat variables. The mean annual concentration of oxidants (which averaged 18 parts per 100 million on the 11 most polluted sites) is statistically indicated as the most likely causal factor. Sites of high oxidant levels in the region are also characterized by declining species richness and equitability.
Demographic Consequences of Incest Tabus: A Microsimulation Analysis
Authors: Hammel E. A. , McDaniel C. K. , Wachter K. W.
Published: October 2006

Theories of incest tabus usually stress the psychosocial advantages of marriage regulation. But marriage regulation may produce delays in mating and thus loss of fertility to a population. Computer microsimulation experiments measure the amount of fertility that must be achieved outside a normatively specified marriage system in order to keep population constant. This amount varies directly with scope of tabu and inversely with population size. For populations of hundreds it is negligible, but for populations of dozens it can be very great. In the latter, flexibility of marital arrangements may permit maintenance of fertility without repeated revision of rules of marriage.
Thermal Structure of the Deep Pacific Ocean in the Early Pliocene
Authors: Keigwin Lloyd D. , Bender Michael L. , Kennett James P.
Published: October 2006

The thermal structure of the Pacific Ocean between water depths of about 1 and 4.5 kilometers is estimated from the oxygen isotopic ratio of benthonic foraminifera from deep-drilled and piston cores of early Pliocene age (about 3 to 5 million years ago). The ratio of oxygen-18 to oxygen-16 in the early Pliocene at each site varies by an average of only ± 0.12 per mil (1 standard deviation). A plot of the oxygen isotopic ratio against modern bottom-water temperature is adequately fit by a line having a slope of – 0.26 per mil per degree Celsius (the equilibrium temperature dependence of calcite-water fractionation), suggesting that the temperature gradient of the Pacific Ocean during the early Pliocene was similar to that of today.
Stimulation of Dopamine Synthesis in Caudate Nucleus by Intrastriatal Enkephalins and Antagonism by Naloxone
Authors: Biggio G. , Casu M. , Corda M, G. , Di Bello C. , Gessa G. L.
Published: October 2006

The intraventricular injection of methionine-enkephalin (50 to 100 micrograms) or [D-Ala
2
]-methionine-enkephalinamide (1.5 to 12 micrograms), a synthetic enkephalin analog resistant to enzyme degradation, caused a marked dose-dependent increase in dihydroxyphenylacetic acid and homovanillic acid concentrations in the rat striatum. The [D-Ala
2
] analog increased the accumulation of dopa in the striatum after aromatic amino acid decarboxylase inhibition, indicating that it increased dopamine synthesis. At the highest doses used both enkephalins failed to modify brain serotonin metabolism. The monolateral microinjection of the [D-Ala
2
] analog (3 to 6 micrograms) into the caudate nucleus increased the concentration of dihydroxyphenylacetic acid in the injected side, whereas bilateral injection increased the concentration of this compound in both caudate nuclei and caused catalepsy. The stimulant effect of the [D-Ala
2
] analog on dopamine synthesis in the striatum persisted after destruction of striatal postsynaptic dopamine receptors with kainic acid. The biochemical and behavioral effects of enkephalins were prevented by naloxone, a specific narcotic antagonist. The results indicate that enkephalins stimulate dopamine synthesis by an action on opioid receptors localized on dopaminergic nerve terminals.
Extreme Ultraviolet Observations from Voyager 2 Encounter with Jupiter
Authors: Sandel B. R. , Shemansky D. E. , Broadfoot A. L. , Bertaux J. L. , Blamont J. E. , Belton M. J. S. , Ajello J. M. , Holberg J. B. , Atreya S. K. , Donahue T. M. , Moos H. W. , Strobel D. F. , McConnell J. C. , Dalgarno A. , Goody R. , McElroy M. B. , Takacs P. Z.
Published: October 2006

Extreme ultraviolet spectral observations of the Jovian planetary system made during the Voyager 2 encounter have extended our knowledge of many of the phenomena and physical processes discovered by the Voyager 1 ultraviolet spectrometer. In the 4 months between encounters, the radiation from Io's plasma torus has increased in intensity by a factor of about 2. This change was accompanied by a decrease in plasma temperature of about 30 percent. The high-latitude auroral zones have been positively associated with the magnetic projection of the plasma torus onto the planet. Emission in molecular hydrogen bands has been detected from the equatorial regions of Jupiter, indicating planetwide electron precipitation. Hydrogen Lyman α from the dark side of the planet has been measured at an intensity of about 1 kilorayleigh. An observation of the occultation of α Leonis by Jupiter was carried out successfully and the data are being analyzed in detail.
Interplanetary Dust: Trace Element Analysis of Individual Particles by Neutron Activation
Authors: Ganapathy R. , Brownlee D. E.
Published: October 2006

Although micrometeorites of cometary origin are thought to be the dominant component of interplanetary dust, it has never been possible to positively identify such micrometer-sized particles. Two such particles have been identified as definitely micrometeorites since their abundances of volatile and nonvolatile trace elements closely match those of primitive solar system material.
Synaptic Potentials in Sympathetic Ganglia: Are They Mediated by Cyclic Nucleotides?
Authors: Busis Neil A. , Weight Forrest F. , Smith Peter A.
Published: October 2006

The hypothesis that cyclic nucleotides are intracellular second messengers mediating the generation of synaptic potentials was studied in the sympathetic ganglia of the bullfrog. Synaptic potentials and the effect of administering cyclic nucleotides and agents which affect cyclic nucleotide metabolism were recorded by the sucrose gap technique. The administration of adenosine 3′,5′-monophosphate (cyclic AMP), guanosine 3′,5′-monophosphate (cyclic GMP), or several of their derivatives produced little or no change in membrane potential. Prostaglandin E
1
did not block the generation of postsynaptic potentials. Theophylline produced membrane effects that were different from those associated with postsynaptic potential generation; it also reduced the slow excitatory postsynaptic potential (EPSP) and potentiated the slow inhibitory postsynaptic potential (IPSP). The administration of papaverine, however, reduced both the slow EPSP and the slow IPSP. Although synaptic stimulation increases both cyclic GMP and cyclic AMP in these neurons, these results raise the possibility that these cyclic nucleotides may have functional roles other than mediation of synaptic potentials.
Reversed-Phase, High-Pressure Liquid Chromatography of Peptides and Proteins with Ion-Pairing Reagents
Authors: Hancock W. S. , Bishop C. A. , Prestidge R. L. , Harding D. R. K. , Hearn M. T. W.
Published: October 2006

Reversed-phase, high-pressure liquid chromatography has been successfully applied to the analysis of peptides and proteins by the addition of hydrophilic (for example, phosphoric acid) or hydrophobic (for example, hexanesulfonic acid) ion-pairing reagents, or both, to the mobile phase. Examples described included proteins such as insulin, glucagon, and 1-24 ACTH pentaacetate (ACTH is adrenocorticotrophic hormone).
Net Energy Analysis of Alcohol Production from Sugarcane
Authors: Hopkinson C. S. , Day J. W.
Published: October 2006

Energy requirements were calculated for the agricultural and the industrial phase of ethyl alcohol production from sugarcane grown in Louisiana. Agricultural energy requirements comprised 54 percent of all energy inputs, with machinery, fuel, and nitrogen fertilizer representing most of the energy subsidies. Overall net energy benefits (output:input) for alcohol production ranged from 1.8:1 to 0.9:1 depending on whether crop residues or fossil fuels were used for industrial processes.
Preliminary Results on the Plasma Environment of Saturn from the Pioneer 11 Plasma Analyzer Experiment
Authors: Wolfe J. H. , Mihalov J. D. , Collard H. R. , McKibbin D. D. , Frank L. A. , Intriligator D. S.
Published: October 2006

The Ames Research Center Pioneer 11 plasma analyzer experiment provided measurements of the solar wind interaction with Saturn and the character of the plasma environment within Saturn's magnetosphere. It is shown that Saturn has a detached bow shock wave and magnetopause quite similar to those at Earth and Jupiter. The scale size of the interaction region for Saturn is roughly one-third that at Jupiter, but Saturn's magnetosphere is equally responsive to changes in the solar wind dynamic pressure. Saturn's outer magnetosphere is inflated, as evidenced by the observation of large fluxes of corotating plasma. It is postulated that Saturn's magnetosphere may undergo a large expansion when the solar wind pressure is greatly diminished by the presence of Jupiter's extended magnetospheric tail when the two planets are approximately aligned along the same solar radial vector.
Camouflage by Integumentary Wetting in Bark Bugs
Authors: Silberglied Robert , Aiello Annette
Published: October 2006

Unlike most insect integuments, the body surfaces of certain bark-inhabiting bugs are wettable. A thin film of water reduces the reflectivity of the insect, resulting in a close match with the wettable bark upon which it rests. Wettability probably aids in concealing the insects from predators.
Heat Transport by Currents Across 25°N Latitude in the Atlantic Ocean
Authors: Bryden Harry L. , Hall Mindy M.
Published: October 2006

The heat transported by currents across 25°N in the Atlantic Ocean is estimated from oceanographic measurements to be 1.1 × 10
15
watts northward. This figure agrees, within estimated error, with the value obtained from charts of energy exchange between ocean and atmosphere but is smaller by a factor of 2 than the recent value derived from satellite radiation measurements.
Sulfide Deposits from the East Pacific Rise Near 21°N
Authors: Hekinian R. , Fevrier M. , Bischoff J. L. , Picot P. , Shanks W. C.
Published: October 2006

Massive sulfide deposits were discovered from the diving saucer
Cyana
on the accreting plate boundary region of the East Pacific Rise near 21°N. The deposits form conical and tubular structures lying on a basaltic basement. Mineralogical and geochemical analyses showed two main types of intimately associated products: a polymetallic sulfide-rich material composed of pyrite and marcasite in association, zinc-rich phases, and copper-rich compounds, and an iron-rich oxide and hydroxide material (also called gossan) composed largely of goethite and limonite. Silicate phases such as opaline, silica, iron-silicon clay, and trace amounts of mica and zeolite are encountered in both types of material. Possible mechanisms for the formation of the sulfide deposits on the East Pacific Rise are discussed.
Formamidine Pesticides: Octopamine-Like Actions in a Firefly
Authors: Hollingworth Robert M. , Murdock Larry L.
Published: October 2006

The formamidine pesticide chlordimeform and its
N
-demethylated metabolites cause the light organ of the firefly
Photinus pyralis
L. to glow brightly. Monodemethyl chlordimeform is active at doses as low as 5 nanograms per insect when applied topically. This action is postsynaptic and probably involves membrane-bound receptors since cyproheptadine blocks the glows induced by both monodemethyl chlordimeform and octopamine, the putative neurotransmitter in the light organ. The pesticidal and pestistatic properties of the formamidines may result from actions on octopaminergic systems.
Convection in a Rotating Layer: A Simple Case of Turbulence
Authors: Busse F. H. , Heikes K. E.
Published: October 2006

Convection in a layer heated from below and rotating about a vertical axis exhibits a unique phenomenon in fluid dynamics in that the small-amplitude motion is governed by random effects in both its spatial and its time dependence. A simple theoretical description of the phenomenon is compared with laboratory observations. A more detailed mathematical description appears to be feasible because of the weakly nonlinear nature of the problem.
Preschool Programs and Later School Competence of Children from Low-Income Families
Authors: Darlington Richard B. , Royce Jacqueline M. , Snipper Ann Stanton , Murray Harry W. , Lazar Irving
Published: October 2006

At follow-up in 1976, low-income children who had attended infant and preschool programs in the 1960's had significantly higher rates of meeting school requirements than did controls, as measured by lower frequency of placement in special education classes and of being retained in grade (held back).
Nuclear Processing and Isotopes in the Galaxy
Authors: Penzias Arno A.
Published: October 2006

The galactic distributions of the stable isotopic species of hydrogen, carbon, nitrogen, oxygen, sulfur, and silicon have been derived from the study of interstellar molecules which contain them. The resulting observational framework appears consistent with our general understanding of stellar evolution and nuclear processing in the galaxy. The greater amount of star formation that has taken place near the center of our galaxy is reflected in an enhanced abundance of processed material, notably carbon-13, in this region. Significant differences between abundances of isotopes in the solar system and corresponding values in interstellar space are also evident. Although some of these differences merely reflect the results of additional stellar processing since the condensation of the presolar nebula some 5 billion years ago, others suggest that a significant amount of atypical nuclear material is associated with the solar system.
Trends in Polymer Development
Authors: Anderson B. C. , Bartron L. R. , Collette J. W.
Published: October 2006

Polymer science and technology has flourished as polymers with many new compositions have been, synthesized. The range of properties attainable has been continually extended, providing materials with higher strength, better reinforcing capabilities, and greater resistance to extreme thermal and corrosive environments. Examples of evolutionary developments in the polyamides, the fluorocarbon resins, and the aromatic engineering plastics are used to illustrate the trends. It is expected that this process will continue in order to meet changing needs and that emphasis will be put on selective polymer design for specific applications.
High-Temperature Structural Ceramics
Authors: Katz R. Nathan
Published: October 2006

The unique properties of ceramics based on silicon carbide and silicon nitride make them prime candidates for use in advanced energy conversion systems. These compounds are the bases for broad families of engineering materials, whose properties are reviewed. The relationships between processing, microstructure, and properties are discussed. A review and assessment of recent progress in the use of these materials in high-temperature engineering systems, and vehicular engines in particular, is presented.
Molecular Beam Epitaxy
Authors: Panish M. B.
Published: October 2006

Molecular beam epitaxy is an ultrahigh vacuum technique for growing very thin epitaxial layers of semiconductor crystals. Because it is inherently a slow growth process, extreme dimensional control over both major compositional variations and impurity incorporation can be achieved. The result is that it has been possible, with one combination of lattice-matched semiconductors, GaAs and Al

x

-Ga

1–
x

As, to demonstrate a large variety of novel single-crystal structures. These results have important implications for fundamental studies of the physics of thin-layered structures and for the development of new semiconductor electronic and optoelectronic devices.
Cloned Cauliflower Mosaic Virus DNA Infects Turnips (
Brassica rapa
)
Authors: Howell Stephen H. , Walker Linda L. , Dudley R. K.
Published: October 2006

Cauliflower mosaic virus DNA cloned in the Sal I site of bacterial plasmid pBR322 infects turnip plants. The cloned viral DNA must be excised from the recombinant plasmid to infect, but need not be circularized and ligated in vitro. The cloned viral DNA lacks site-specific single-strand breaks found in DNA obtained directly from the virus. However, these breaks are reintroduced into the viral genome during multiplication of the virus in the plant host.
Anionic Constitution of 1-Atmosphere Silicate Melts: Implications for the Structure of Igneous Melts
Authors: Virgo D. , Mysen B. O. , Kushiro I.
Published: October 2006

A structural model is proposed for the polymeric units in silicate melts quenched at 1 atmosphere. The anionic units that have been identified by the use of Raman spectroscopy are SiO
4
4–
monomers, Si
2
O
7
6–
dimers, SiO
3
2–
chains or rings, Si
2
O
5
2–
sheets, and SiO
2
three-dimensional units. The coexisting anionic species are related to specific ranges of the ratio of nonbridging oxygens to tetrahedrally coordinated cations (NBO/Si). In melts with 2.0 < NBO/Si < ∼ 4.0, the equilibrium is of the type Si
2
O
7
6–
⇄ SiO
4
4-
+ SiO
3
2-
. In melts with NBO/Si ∼ 1.0 to 2.0, the equilibrium anionic species are given by 3SiO
3
2–
⇄ SiO
4
4-
+ SiO
5
2-
. In alkali-silicate melts with NBO/Si ≲ 1.3 and in aluminosilicate melts with NBO/
T
< 1.0, where
T
is (Si + Al), the anionic species in equilibrium are given by Si
2
O
5
2–
⇄ SiO
3
2-
+ SiO
2
. In multicomponent melts with compositions corresponding to those of the major igneous rocks, the anionic species are
T
O
2
,
T
2
O
5
,
T
2
O
6
, and
T
O
4
, and the coexisting polymeric units are determined by the second and third of these disproportionation reactions.
Physics
Authors: Bromley D. Allan
Published: October 2006

From massive quarks deep in the hearts of atomic nuclei to the catastrophic collapse of giant stars in the farthest reaches of the universe, from the partial realization of Einstein's dream of a unified theory of the forces of nature to the most practical applications in technology, medicine, and throughout contemporary society, physics continues to have a profound impact on man's view of the universe and on the quality of life. The author argues that the past few years, in terms of new discoveries, new insight—and the new questions—have been among the most productive in the history of the field and puts into context his selection of some of the most important new developments in this fundamental science.
Engineering Enters New Cycle of Development and Definition
Authors: Rogers Kenneth C.
Published: October 2006

The profession of engineering is evidencing important changes under the impact of the microprocessor and the energy crisis. Societal considerations are altering the normative criteria of engineering while computerized manufacturing systems require entirely new engineering approaches. The trend is toward greater autonomy of engineering from the traditional basic sciences. Significant changes in engineering education will be necessary. The new technological environment requires closer links among academia, industry, and the professional societies—engineering's essential triad.
Operations Research and Systems Analysis
Authors: Miser Hugh J.
Published: October 2006

The science of man-machine operating systems, which includes operations research and systems analysis, has achieved a substantial body of theory and application over the last 40 years. Its current strength prompts it to attack difficult large-scale problems while challenging the other relevant sciences to unite, not only with each other and operations and systems research, but also with society, to deal with some of the most widespread and important problems of our time.
Environment
Authors: White Gilbert F.
Published: October 2006

In contrast to the approaches to resource management and preservation of the past decade, a new perspective on environmental problems is emerging. Six major trends in scientific thinking are (i) increased efforts to examine environments in holistic frameworks, (ii) greater attention to life support systems, (iii) enlarged canvass of the range of choices in resource management, (iv) refinement in methods of risk assessment, (v) streamlined methods for monitoring environmental change, and (vi) more emphasis on the global framework.
Frontiers in Chemistry
Authors: Joyce Robert M
Published: October 2006

Chemical synthesis is the ultimate source of most of the new materials that serve society. Progress in chemical synthesis depends on comparable advances in other branches of chemistry, such as in analysis, methods for determining the intimate details of chemical structures and of reaction mechanisms, and theories of chemical structure and reactions. Recent progress in some of these areas of chemistry is described.