bluuebunny/crossref_metadata_2025 huggingface dataset:
Age Changes in the Neuronal Microenvironment
Authors: Bondareff William , Narotzky Robert
Published: October 2006

The extracellular space of the rat brain was visualized by electron microscopy in sections of cerebral cortex fixed by freeze-substitution. The volume of tissue occupied by the extracellular space was estimated stereometrically, and was found to decrease from 20.8 percent in 3-month-old rats to 9.6 percent in senescent animals, 26 months of age. This decrease in extracellular space indicates an age-associated change in the microenvironment of nerve cells.
Destruction of Cytochrome P
450
by Secobarbital and Other Barbiturates Containing Allyl Groups
Authors: Levin W. , Sernatinger E. , Jacobson M. , Kuntzman R.
Published: October 2006

Administration of certain commonly used barbiturates containing allyl groups, such as secobarbital, allobarbital, or aprobarbital to rats treated chronically with a microsomal enzyme inducer causes a rapid destruction of the liver microsomal hemoprotein that serves as the terminal oxidase for drug metabolism. In contrast, barbiturates without an allyl group do not have this effect. The decrease in this hemoprotein, cytochrome P
450
, by the barbiturates containing an allyl group could also be demonstrated in an in vitro liver microsomal system requiring reduced nicotinamide adenine dinucleotide phosphate. These results suggest that the barbiturates containing an allyl group are converted to a metabolite that leads to the destruction of cytochrome P
450
.
Second-Order Scattering from the Sea: Ten-Meter Radar Observations of the Doppler Continuum
Authors: Tyler G. Leonard , Faulkerson William E. , Peterson Allen M. , Teague Calvin C.
Published: October 2006

Ten-meter radar observations of the sea have been used to study second-order interactions between waves in electromagnetic scattering from the sea. Techniques of coherent, pulsed radar provide echo frequency spectra from several range intervals. The echo spectra are resolved with an analysis window of a few millihertz. These spectra show a clear second-order echo continuum which appears as sidebands about the first-order Bragg scattering lines. Up to one-half of the total echo power has been observed in these sidebands. The principal characteristics of these sidebands vary with time, apparently in response to the sea state. The form of the echo spectra is consistent with the results of perturbation theory computations based on Rice's method.
Sea Level at Southern California: A Decadal Fluctuation
Authors: Namias Jerome , Huang Joseph Chi Kan
Published: October 2006

The winter mean height of sea level at southern California rose 5.6 centimeters between the periods 1948-1957 and 1958-1969. These periods correspond to two fairly coherent large-scale climatic regimes with different air-sea coupling, which were previously identified. The rise was mainly due to a change in the thermohaline structure of the water as a result of changes in prevailing winds.
An Isomorphous Heavy-Atom Derivative of Crystalline Formylmethionine Transfer RNA
Authors: Schevitz R. W. , Navia M. A. , Bantz D. A. , Cornick G. , Rosa J. J. , Rosa M. D. H. , Sigler P. B.
Published: October 2006

An isomorphous osmium derivative of crystalline yeast initiator transfer RNA has been prepared and interpreted to 6-angstrom resolution. The coordinates of the heavy atoms have been determined by Patterson and "direct" methods applied to the difference coefficients of the centric projections, followed by least-squares refinement. There is one dominant site per asymmetric unit, consistent with the finding by neutron-activation analysis that there is approximately one osmium atom per molecule of transfer RNA. The osmium derivative appears to be a normal substrate for enzymatic aminoacylation.
Development of a Receptor on a Foreign Nerve Fiber in a Pacinian Corpuscle
Authors: Schiff J. , Loewenstein W. R.
Published: October 2006

When the sensory fiber of a Pacinian corpuscle (in cat mesentery) is transected (at the inferior mesenteric nerve) transduction fails within 30 hours: the nerve ending produces no generator potentials in response to mechanical stimulation. Electrically elicited nerve impulse conduction continues for at least another 18 hours. A transducer mechanism develops on a regenerating nerve fiber when this fiber enters the denervated corpuscle. Such transducer development takes place on myelinated fibers from the inferior mesenteric nerve, which normally supplies corpuscles, as well as on myelinated hypogastric nerve fibers, which normally do not go to corpuscles, including fibers larger than the original corpuscle afferents.
Histochemical Phosphorylase Activity in Regenerating Muscle Fibers from Myophosphorylase-Deficient Patients
Authors: Roelofs R. I. , Engel W. K. , Chauvin P. B.
Published: October 2006

Fresh frozen sections of mature skeletal muscle fibers from patients with genetically determined "absence" of skeletal muscle phosphorylase (McArdle's disease) have no histochemical phosphorylase activity. That regenerating muscle fibers, in vitro and in vivo, from such patients do have histochemical phosphorylase activity present suggests a loss of enzyme activity with fiber maturity.
Coding Properties of Reticulocyte Lysine Transfer RNA's in Hemoglobin Synthesis
Authors: Woodward William R. , Herbert Edward
Published: October 2006

Two isoacceptor transfer RNA's for lysine were found in rabbit reticulocytes. The codon recognition properties of these isoacceptors were studied in hemoglobin synthesis in a cell-free system. The two isoacceptors transferred lysine into different sites in hemoglobin, but showed no preference for one chain over the other. Codon cross recognition was less than 4 percent.
Wing Movements of Calling Katydids: Fiddling Finesse
Authors: Walker Thomas J. , Dew Donald
Published: October 2006

Stridulating Uhler's katydids produce the most complex song known for insects. Series of four types of sounds are made in stereotyped sequence. Sound-synchronized high-speed photography reveals that each type of sound is produced by a distinctively different wing-movement cycle. The most complex of these cycles includes a two-step closure and a nearly silent close-open movement.
Galactokinase: Evidence for a New Racial Polymorphism
Authors: Tedesco Thomas A. , Bonow Robert , Miller Karen , Mellman William J.
Published: October 2006

Activities of galactokinase and galactose-1-phosphate uridyltransferase in red cells were assayed in a mixed racial population of 645 pregnant women. The distribution of individual transferase activities for black subjects was the same as that for whites. In contrast, the distributions of individual galactokinase activities differed significantly in blacks and whites, the mean for the black population being 30 percent lower than the mean for the white population. The same racial difference was found when red cell galactokinase activity was examined in males and in newborns. Because low-, intermediate-, and high-galactokinase activities appear to segregate within several black families, this observed difference suggests a new, racially determined enzyme polymorphism.
Polar Motion from Laser Tracking of Artificial Satellites
Authors: Smith David E. , Kolenkiewicz Ronald , Dunn Peter J. , Plotkin Henry H. , Johnson Thomas S.
Published: October 2006

Measurements of the range to the Beacon Explorer C spacecraft from a single laser
tracking system at Goddard Space Flight Center have been used to determine the change in
latitude of the station arising from polar motion. A precision of 0.03 arc second was
obtained for the latitude during a 5-month period in 1970.
Obesity: Evidence of Decreased Secretion of Glucagon
Authors: Wise Jonathan K. , Hendler Rosa , Felig Philip
Published: October 2006

The increase in concentration of glucagon in plasma caused by infusion of alanine was reduced in obese subjects as compared to that in nonobese control subjects. This was true when the subjects were in the postabsorptive state as well as after an 84-hour fast, at which time the basal glucagon concentration had risen in the nonobese subjects, but remained unaltered in the obese group.
Gravitational Effects on Concentrations and Partial Pressures in Solutions: A Thermodynamic Analysis
Authors: Andrews Frank C.
Published: October 2006

Thermodynamic analysis establishes the equilibrium relationships between the concentrations and partial pressures of the components of liquid and gaseous solutions in the presence of a gravitational field. The conditions of equilibrium between a column of gas and gas-saturated water and the conditions of equilibrium governing a model of the distribution of radioactive heat sources in surface rocks are deduced from the theory.
Soluble Membrane Antigens of Lip and Cervical Carcinomas: Reactivity with Antibody for Herpesvirus Nonvirion Antigens
Authors: Hollinshead Ariel C. , Tarro Giulio
Published: October 2006

With the use of antibody for herpesvirus nonvirion antigens (not structural components of the virus) complement fixing reactivity has been shown for soluble membrane antigens separated from lip and cervical carcinomas but not for similar extracts from normal vaginal tissue or intestinal carcinoma. Neither the serum obtained from the guinea pig before hyperimmunization with the herpesvirus nonvirion antigen nor the antiserum of guinea pigs immunized with comparable uninfected cell extracts reacted with these tumor soluble membrane antigens. Since the above soluble membrane antigens could be specific markers for the presence of virus genome within the tumor cells, the findings could support an etiological role of herpesvirus in selected human malignancies.
SV40 Virus Transformation of Mouse 3T3 Cells Does Not Specifically Enhance Sugar Transport
Authors: Romano A. H. , Colby C.
Published: October 2006

The apparent enhancement of 2-deoxy-D-glucose uptake by mouse 3T3 cells accompanying transformation by SV40 virus is not due primarily to an effect on the transport process but to enhanced phosphorylation of the sugar by intracellular kinases. Moreover, the effect is not specifically a function of the presence of the viral genome, but is a reflection of the overall growth rate and physiological state of the cell.
Lethal Interaction of Ubiquitous Insecticide Carriers with Virus
Authors: Crocker John F. S. , Ozere Rudy L. , Safe Stephen H. , Digout Sharon C. , Rozee Kenneth R. , Hutzinger Otto
Published: October 2006

Large quantities of presumably nontoxic petroleum oil by-products are introduced into the environment as pesticide dispersal agents and emulsifiers. An increase in viral lethality with a concomitant influence on the liver and central nervous system occurs in young mice previously primed with such chemicals.
Cranial Anatomy of
Oreopithecus
Authors: Szalay Frederick S. , Berzi Annalisa
Published: October 2006

Reexamination of the 1958 skull of the late Miocene
Oreopithecus bambolii
revealed a cranial anatomy different from that widely accepted for this taxon. There is a sagittal crest, a high nuchal crest, a large gonial angle, and a high, rather vertical, occiput. This catarrhine was not a very large brained primate compared to known advanced hominoids.
Tobacco and Evoked Potential
Authors: Hall R. A. , Rappaport M. , Hopkins H. K. , Griffin R.
Published: October 2006

Significant changes were found in two indices of the averaged visual evoked potentials in nine smokers after 12 and 36 hours of abstinence and after resumption of smoking. There was a decrease of the amplitude envelope accompanying withdrawal and an increase with resumption of smoking. These changes are consistent with the contention that tobacco increases arousal. Amplitude changes were found in a specific component of the evoked potential occurring between 100 and 125 milliseconds after the onset of the flash. The latter changes suggest the possibility that smoking selectively enhances the perception of weak stimuli.
Cyclic AMP Phosphodiesterase in Cloned Astrocytoma Cells: Norepinephrine Induces a Specific Enzyme Form
Authors: Uzunov Petko , Shein Harvey M. , Weiss Benjamin
Published: October 2006

The soluble supernatant fraction of homogenates of cloned rat astrocytoma cells (linle C-2A) was subjected to polyacrylamide gel electrophoresis. Two peaks of adenosine 3′,5′-monophosphate phosphodiesterase activity were found, corresponding to peaks I and IV of a similarly prepared homogenate of rat brain. Incubating cells with norepinephrine (0.3 millimolar) caused about a threefold increase in the activity of peak IV but no change in peak I. This increase was completely inhibited by prior incubation with propranolol (0.1 millimolar), a beta-adrenergic blocking agent, or with cyclohexamine (40 micromolar), a protein synthesis inhibitor. Induction of a specific phosphodiesterase form by norepinephrine suggests another feedback control mechanism whereby an organism can prevent the effects of excessive sympathetic activity.
Nonvisual Photic Responsiveness in Newly Hatched Pigeons (
Columba livia
)
Authors: Harth Marshall Stephen , Heaton Marieta Barrow
Published: October 2006

Overt behavioral arousal was elicited by light stimulation in pigeon hatchlings. The sensitivity is not mediated via the retina or by direct stimulation of the brain, but rather it is most likely a dermal sensitivity.
Inorganic Nitrogen Removal from Wastewater: Effect on Phytoplankton Growth in Coastal Marine Waters
Authors: Goldman Joel C. , Tenore Kenneth R. , Stanley Helen I.
Published: October 2006

Algal bioassays were used to demonstrate the high efficiency of a combined tertiary wastewater treatment and marine aquaculture system in removing inorganic nitrogen, and to show that the coastal waters off Woods Hole, Massachusetts, are limited in nitrogen for marine phytoplankton growth. When nutrients were removed from secondarily treated domestic wastewater through assimilation by phytoplankton in an outdoor growth pond, the pond effluent, in varying dilutions with seawater, could not support more phytoplankton growth than the seawater alone. However, when nitrogen was added back to the mixtures of pond effluent and seawater, the phytoplankton growth response was similar to that with a mixture of wastewater and seawater. This is similar to the findings of other researchers, and suggests that nitrogen may be the key growth-limiting nutrient in many coastal marine waters. The combined tertiary treatment-marine aquaculture system appears to be an effective means of removing nitrogen from secondarily treated wastewater and controlling eutrophication of coastal marine waters.
Δ
9
-Tetrahydrocannabinol and Ethanol: Differential Effects on Sympathetic Activity in Differing Environmental Setting
Authors: Ng Lorenz K. Y. , Lamprecht Friedhelm , Williams Redford B. , Kopin Irwin J.
Published: October 2006

Serum dopamine β-hydroxylase activity, a useful biochemical index of peripheral sympathetic nervous activity, was measured in rats treated with Δ
9
-tetrahydrocannabinol or ethanol or both substances. After 7 days of treatment with either substance, serum dopamine β-hydroxylase activity decreased significantly. Combined treatment with both agents enhanced the effects of each given alone. In rats subjected to immobilization stress, treatment with Δ
9
-tetrahydrocannabinol appeared to potentiate the stress-induced increase in serum enzyme activity. Treatment with ethanol, with or without Δ
9
-tetrahydrocannabinol, effectively blocked this increase in enzyme activity. These results show that both substances have significant effects on the sympathetic nervous system which are critically influenced by environmental setting.
Embryonal Neoplasms in the Opossum: A New Model for Solid Tumors of Infancy and Childhood
Authors: Jurgelski William , Hudson Pearlie M. , Falk Hans L. , Kotin Paul
Published: October 2006

Opossums fed the chemical carcinogen ethyl nitrosourea early in postnatal life developed a variety of epithelial and mesenchymal embryonal neoplasms that were closely analogous, in morphology and biological behavior, to tumors of human infancy and childhood for which experimental models in laboratory animals are either imprecise or nonexistent. The embryonal tumors were found in association with, and occasionally at the same sites as, a limited number of malformations.
Serological Identification of an Ir-Region Product
Authors: Hauptfeld Věra , Klein Dagmar , Klein Jan
Published: October 2006

Reciprocal immunization of congenic lines differing in the middle portion of the H-2 complex leads to the production of antibodies which react with an antigen or antigens controlled by the Ir region. The antigen designated Ir-1.1 seems to be present only on a subpopulation of lymphocytes from lymph nodes and spleen. It is absent on bone marrow cells.
Aldolase Catalysis: Single Base-Mediated Proton Activation
Authors: Meloche H. Paul , Glusker Jenny Pickworth
Published: October 2006

The enzyme, 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase, catalyzes several reactions, the natural ones being (i) the exchange of hydrogen atoms of the methyl groups of pyruvate with protons of the solvent (C-H synthesis) and (ii) the reversible condensation of pyruvate with D-glyceraldehyde-3-phosphate (C-C synthesis). Previous work has provided chemical evidence for the occurrence of a protein-bound carboxylate group adjacent to the Schiff's base-forming lysine in the active site geometry. This carboxylate could provide the basic group postulated to participate in proton activation catalyzed by aldolases. With the use of three-dimensional models, it is shown that simple rotation about a carbon-carbon bond of the side chain will allow the base to assume the two positions necessary for proton activation in either the C-H synthesis or the C-C synthesis catalyzed by KDPG aldolase. This single base hypothesis provides a model wherein all reagents can approach a single face of the active site and is consistent with the stereochemistry thought to occur in the aldolase reaction.
Peroxidase Mediated Antimicrobial Activities of Alveolar Macrophage Granules
Authors: Paul B. B. , Strauss R. R. , Selvaraj R. J. , Sbarra A. J.
Published: October 2006

The 20,000
g
pellet obtained by centrifugation of a homogenate of rabbit alveolar macrophages has antibacterial activity in the presence of a hydrogen peroxide-generating system and iodide. Peroxidase activity has been demonstrated in this fraction. Addition of 3-amino-1,2,4-triazole diminished the antibacterial activity of the pellet-hydrogen peroxide-iodide system.
Volcanic Gases: Hydrogen Burning at Kilauea Volcano, Hawaii
Authors: Cruikshank Dale P. , Morrison David , Lennon Kenneth
Published: October 2006

Spectroscopic evidence for hydrogen burning in air was obtained at Kilauea Volcano. The abundance of hydrogen required to support combustion is consistent with that predicted for gases in equilibrium with typical Hawaiian tholeiitic basalt.
Neuronal Properties of Nymphal and Adult Insect Neurosecretory Cells in vitro
Authors: Seshan K. R. , Levi-Montalcini Rita
Published: October 2006

Neurosecretory brain cells from late nymphal and adult cockroaches were grown for 1 to 3 months in a chemically defined medium in combined cultures with embryonic organs or oocytes from nymphal and adult specimens. Under these conditions, neurosecretory cells show vigorous axonal growth. Electron dense granules in cell perikarya and axons of 3-month-old cultures are suggestive of neurosecretory activity in vitro.
Delayed Recovery of Function following Orbital Prefrontal Lesions in Infant Monkeys
Authors: Miller Epp A. , Goldman Patricia S. , Rosvold H. Enger
Published: October 2006

Monkeys given orbital prefrontal lesions at 1, 4, or 8 weeks of age exhibited a severe learning disability when they were tested at 1 year of age, but showed substantial recovery by the time they were 2 years old. These results suggest that the protracted maturation of intact cortical regions is important in recovery of function after early brain injury.
Chondrules: An Origin by Impacts between Dust Grains
Authors: Lange David E. , Larimer John W.
Published: October 2006

A barred chondrule in the Ngawi meteorite contains a magnetite spherule embedded in it. The collision between these two objects fractured and partially remelted the chondrule, an indication that the impact velocity was 10
5
to 10
6
centimeters per second. This observation supports Cameron's and Whipple's recent predictions that grains achieved high velocities in the nebula and that the resulting impacts provide a suitable chondrule-forming mechanism.
Linoleic Acid Hydroperoxide: Impaired Bacterial Uptake by Alveolar Macrophages, a Mechanism of Oxidant Lung Injury
Authors: Khandwala A. , Gee J. Bernard L.
Published: October 2006

Exogenous linoleic acid hydroperoxide causes in vitro impairment of both bacterial uptake and the phagocytic stimulation of
14
CO
2
production from [1-
14
C]glucose in rabbit alveolar macrophages by an undefined effect on the cell membrane. This effect may be one mechanism for the defective pulmonary bacterial clearance characteristic of oxidant lung injury.
Programmed Cell Death of T Cells Signaled by the T Cell Receptor and the α
3
Domain of Class I MH
Authors: Sambhara Suryaprakash R. , Miller Richard G.
Published: October 2006

As well as being activated or rendered unresponsive, mature T lymphocytes can be deleted, depending on the signals received by the cell. Deletion by programmed cell death (apoptosis) is triggered if a T cell that has received a signal through its T cell receptor complex also receives a signal through the α
3
domain of its class I major histocompatibility complex (MHC) molecule. Such a signal can be delivered by a CD8 molecule, which recognizes the α
3
domain, or by an antibody to this domain. Precursors of both cytotoxic T lymphocytes (CTL's) and T helper cells are sensitive to this signal but become resistant at some point before completing differentiation into functioning CTL's or T helper cells. Because CTL's carry CD8, they can induce cell death in T cells that recognize them. This pathway may be important in both removal of autoreactive T cells and immunoregulation.
Aging Increases Susceptibility of Mouse Skin to DMBA Carcinogenesis Independent of General Immune Status
Authors: Ebbesen P.
Published: October 2006

The dependence of chemical carcinogenesis on age of target tissue was studied by repeated DMBA-treatment of mouse skin grafted from old and young syngeneic donors to young recipients. Carcinomas developed on 39 percent (16/41) of grafts from old donors and on 12 percent (5/41) of grafts from young donors. The incidence of nonskin lymphoid tumors was highest in male recipients bearing grafts from old donors.
Deuterium Oxide Effect on Temperature-Dependent Survival in Populations of
Drosophila melanogaster
Authors: Samis H. V. , Baird M. B. , Massie H. R.
Published: October 2006

A comparison of the mean life-spans for populations of
Drosophila melanogaster
at 10°, 20°, 25°, and 30°C maintained on media prepared with distilled water and with 50 percent deuterium oxide shows that deuteration decreases longevity at all four temperatures. The magnitude of the difference between the mean survival times of populations maintained on deuterated and nondeuterated media is inversely related to temperature between 10° and 30°C.
Autoimmune Encephalomyelitis: Activation of Thymus Lymphocytes against Syngeneic Brain Antigens in vitro
Authors: Orgad Shlomit , Cohen Irun R.
Published: October 2006

Thymus lymphocytes of normal adult rats were autosensitized in vitro against soluble antigens extracted from the brains of syngeneic rats. Injection of the autosensitized lymphocytes into syngeneic rats led to the development of brain lesions suggestive of autoimmune encephalomyelitis. Injection of control lymphocytes or the antigen extract alone did not cause lesions. Since sensitization in vitro requires the presence of lymphocytes programmed with specific receptors, the results indicate that normal rats have lymphocytes capable of recognizing central nervous system self-antigens. Hence, regulatory mechanisms, inoperative in vitro, probably function in vivo to prevent immune activation of self-recognizing lymphocytes and autoimmunity. This concept suggests a new approach to exploring the pathogenesis of autoimmune diseases.
Site of Neural Attenuation of Responses to Self-Vocalized Sounds in Echolocating Bats
Authors: Suga Nobuo , Shimozawa Tateo
Published: October 2006

Bats of the genus
Myotis
emit intense orientation sounds for echolocation. If such sounds directly stimulated their ears, the detection of echoes from short distances would be impaired. In addition to the muscular mechanism in the middle ear, the bat has a neural mechanism in the brain for attenuation of responses to self-vocalized orientation and nonorientation sounds. This neural attenuating mechanism operates in the nucleus of the lateral lemniscus, reducing its activity by about 15 decibels, and it is synchronized with vocalization.
Preliminary Infrared Radiometry of Venus from Mariner 10
Authors: Chase S. C. , Miner E. D. , Morrison D. , Mnch G. , Neugebauer G.
Published: October 2006

The intensity of emission at 45 micrometers, measured with high spatial resolution along a single crossing of the Venus disk, is presented. On the average, the observed darkening toward the limb varies nearly linearly with the cosine of the emission angle. The brightness temperature, extrapolated to normal emission, is 255°K. The limb darkening curve, interpreted in a linear approximation, implies that the atmosphere is quite opaque, with an absorption coefficient of 0.24 per kilometer. Changes in curvature present in the limb darkening curve suggest the existence of thermal inhomogeneities with scale comparable to that of the dark markings shown by ultraviolet images.
Spermidine in Hormone-Dependent Differentiation of Mammary Gland in vitro
Authors: Oka Takami
Published: October 2006

Stimulation of milk-protein synthesis in mouse mammary epithelium in vitro requires insulin, hydrocortisone, and prolactin. The requirement for hydrocortisone can be replaced by spermidine. The possibility that spermidine mediates the effect of glucocorticoid is also supported by the observation that the cellular spermidine concentration increases before the accelerated synthesis of casein and α-lactalbumin.
Mycoplasma Contamination of Cultured Amniotic Fluid Cells: Potential Hazard to Prenatal Chromosomal Diagnosis
Authors: Schneider E. L. , Stanbridge E. J. , Epstein C. J. , Golbus M. , Abbo-Halbasch G. , Rodgers G.
Published: October 2006

Amniotic fluid cell cultures were screened for mycoplasma contamination. Mycoplasma RNA's were observed in more than half the cultures examined. Karyotypic analyses of these contaminated cell cultures revealed a significant increase in chromosomal aberrations. These studies emphasize the need for screening for mycoplasma in cultured amniotic cells.
Jovian Atmosphere: Structure and Composition between the Turbopause and the Mesopause
Authors: Sagan Arl , Veverka Joseph , Wasserman Lawrence , Elliot James , Liller William
Published: October 2006

The occultation of the star Beta Scorpii by Jupiter was observed at high time resolution in three wavelength channels. The results imply a temperature of 220°K at an altitude in the Jovian atmosphere corresponding to 10
14
molecules per cubic centimeter, and temperature fluctuations of 2° to 10°K over vertical scales of 2 to 10 kilometers. They suggest that the vertical eddy diffusion coefficient near the turbopause has a lower limit of 7 × 10
5
square centimeters per second, and that the turbopause lies above the altitude where the density is 5 × 10
13
molecules per cubic centimeter. Below the turbopause, the ratio of hydrogen to helium is consistent with cosmic abundances.
Learning by Following a Food Source
Authors: Neuringer Allen , Neuringer Martha
Published: October 2006

Hungry pigeons first learned to eat grain from the experimenter's hand. When the hand approached and "pecked" a small disk to produce grain in a food hopper, the pigeons followed the hand and rapidly learned to peck the disk. Birds given operant conditioning training took significantly longer to learn the same response. Under natural conditions, young animals may learn to behave like their parents simply by following parental sources of food.
Raman Spectroscopic Investigation of Gramicidin A′ Conformations
Authors: Rothschild Kenneth J. , Stanley H. Eugene
Published: October 2006

Gramicidin A′ is believed to form transmembrane channels in lipid bilayers and biological membranes. The first Raman spectroscopic study of gramicidin A′ is presented. Evidence is found for two types of conformation. One type is found in the powder and has a Raman spectrum similar to that of model polypeptides with β hydrogen bonding. The second type is found when gramicidin A′ is dissolved in dimethyl sulfoxide.
Enduring Learning Deficits and Cerebral Synaptic Malformation from Exposure to 10 Parts of Halothane per Million
Authors: Quimby Kelvin L. , Aschkenase Lea J. , Bowman Robert E. , Katz Jordan , Chang Louis W.
Published: October 2006

Chronic exposure of rats to 10 parts of halothane per million during early life produced later deficits in learning a shock-motivated light-dark discrimination and a food-motivated maze pattern, correlated with enduring synaptic membrane malformation in cerebral cortex. Adult exposure had no effect. Halothane may provide a useful analytical tool for study of brain. The behavioral-ultrastructural techniques also suggest a standard for assessing the safety of trace toxicants with central nervous system effects.
Attempt to Date Early South African Hominids by Using Fission Tracks in Calcite
Authors: MacDougall D. , Price P. B.
Published: October 2006

Calcite crystals extracted from marrow cavities of bones found in hominid-bearing breccias from Makapansgat and Swartkrans were studied for fossil tracks. The absence of the expected numbers of tracks in these and in calcites from Beds I and II, Olduvai Gorge, combined with the results of laboratory heating experiments, indicates that track annealing has occurred at ambient temperatures and precludes the widespread use of calcite for fission track dating.
Morphine and Ethanol: Selective Depletion of Regional Brain Calcium
Authors: Ross David H. , Medina Miguel A. , Lee Cardenas H.
Published: October 2006

Administration of morphine or ethanol to rats produces a decrease in regional brain calcium in vivo. This effect is selectively antagonized by the stereospecific narcotic antagonist naloxone. Reserpine and the dopamine-acetaldehyde conjugate salsolinol also produce a depletion of regional brain calcium, but only the salsolinol depletion is antagonized by naloxone. Experiments with naloxone provide evidence for two calcium-sensitive pools in the central nervous system.
Fetal Bin Growth: Selective Action by Growth Hormone
Authors: Sara Vicki R. , Lazarus L. , Stuart M. C. , King T.
Published: October 2006

Growth hormone was administered to pregnant rats maintained under dietary control, and fetal and placental growth and nutrition were examined. Growth hormone had a selective action on brain growth that could not be attributed to nutrient mobilization but suggested a trophic factor which is unique to the brain.
5-Methyltetrahydrofolic Acid as a Mediator in the Formation of Pyridoindoles
Authors: Mandel Lewis R. , Rosegay Avery , Walker Robert W. , VandenHeuvel W. J. A. , Rokach Joshua
Published: October 2006

Enzymes from chick and rat tissues catalyze the reaction of
N
-methyltryptamine with 5-methyltetrahydrofolic acid to form 2,3,4,9-tetrahydro-2-methyl-1
H
-pyrido[3,4
b
]indole.
N,N
-Dimethyltryptamine was not formed. With tryptamine as substrate the product is 2,3,4,9-tetrahydro-1
H
-pyrido[3,4
b
]indole and not
N
-methyltryptamine. These pyridoindoles were not formed when
S
-adenosylmethionine was cosubstrate.
Io: A Surface Evaporite Deposit?
Authors: Fanale F. P. , Johnson T. V. , Matson D. L.
Published: October 2006

A model is suggested for Io's surface composition involving evaporite salt deposits, rich in sodium and sulfur. According to this model, these deposits were produced as a result of the migration of salt-saturated aqueous solutions to Io's surface from a warm or hot interior followed by loss of the water to space. This model satisfies cosmochemical constraints based on Io's initial composition, current density, and thermal history. Salt-rich assemblages are easily derivable from the leaching of carbonaceous chondritic material; the chemical and optical properties of such deposits, after modification by irradiation, can be used to explain Io's overall albedo and spectral reflectance, its dark reddish poles, and the observed sodium emission as well as or better than other currently suggested materials.
Mercury Monitor for Ambient Air
Authors: Hadeishi T. , Church D. A. , McLaughlin R. D. , Zak B. D. , Nakamura M. , Chang B.
Published: October 2006

An isotope-shift, Zeeman-effect atomic absorption spectrometer has been demonstrated to have sufficient sensitivity to continuously monitor the total mercury content of ambient air. At present, the minimum total mercury concentration detectable with this device is 0.2 microgram per cubic meter of air—one fifth of the proposed federal guideline. This is the first technique which responds to both mercury vapor and mercury in particulates available for continuous monitoring at this concentration.
Pioneer 10 Jovian Encounter: Radiation Dose and Implications for Biological Lethality
Authors: Miller Morton W. , Kaufman Gary E. , Maillie H. David
Published: October 2006

In its recent Jupiter flyby Pioneer 10 passed through a belt of intense particulate radiation. The radiation dose on the outer surface of the spacecraft was at least 4.9 × 10
5
rads from electrons plus 2.9 × 10
6
rads from protons, sufficient to cause significant microbial decontamination. The radiation dose inside Pioneer 10, approximately 2.8 × 10
5
to 4.9 × 10
5
rads, was less likely to cause microbial decontamination but would be lethal to man and to most multicellular biological organisms.
Restored Pictures of Ganymede, Moon of Jupiter
Authors: Frieden B. Roy , Swindell William
Published: October 2006

Restored pictures of Ganymede have been produced that have some identifiably reliable features and some identifiable artifacts. The latter arise from artifacts in parts of the red image data. Among the presumably reliable features are some mare-like objects (perhaps with some internal structure), and a few rather large, bright rings. Whether the latter are ice, or arise from near-specular reflection from smooth surface features, is left for future investigation.

One of the restoring methods used, maximum entropy, has been shown to be applicable to moderately extended images. In view of its short time requirements (30 seconds per picture), the method should be applicable to moderately larger images, for example with twice the given number of data points.
Cryptoses choloepi
: A Coprophagous Moth That Lives on a Sloth
Authors: Waage Jeffrey K. , Montgomery G. Gene
Published: October 2006

The larvae of the sloth moth,
Cryptoses choloepi
, live in the dung of the three-toed sloth,
Bradypus infuscatus
. Adult female moths apparently leave the fur of the sloth to oviposit when the sloth descends, once a week, to the forest floor to defecate. Newly emerged moths fly from the dung pile into the forest canopy to find a sloth.
X-rays from Coalescing Atoms
Authors: Meyerhof Walter E.
Published: October 2006

The discovery and investigation of x-ray continua has provided a new tool for studying the detailed electronic processes that occur when atoms collide. In the collisions considered here, the quasimolecular origin of the continuum radiation has been established. Therefore, as the atomic numbers of the projectiles and target atoms are increased one can simulate some of the properties of superheavy atoms. In particular, the peaked nature of the x-ray energy dependence of the anisotropy of
K
,
L
, and
M
MO radiation, as well as the peaked nature of the
M
MO spectra, will allow approximate spectroscopic studies of superheavy atoms. Special excitement attaches to the possibility of observing fundamental processes occurring under extremely high electric and magnetic fields. The recent successful development of a 1400-Mev U beam at the GSI (Gesellschaft für Schwerionenforschung) accelerator in Darmstadt, Germany, promises an imminent attack on these basic problems.
Short-Period Climatic Fluctuations: Effects on Diatom Biomass
Authors: Tont Sargun A.
Published: October 2006

An analysis of the weekly averages of diatom biomass measured near the coast of Southern California (32°50′N, 117°10′W) during the period from 1928 through 1939 indicates that three major blooms account for 85 percent of each year's diatom biomass. The average duration of a single bloom is 5.5 weeks. The diatom blooms coincide with upwelling, but their individual characteristics depend on the detailed features of the circulation patterns of the water masses. That is, if upwelling takes place after a large influx of subtropical or even tropical water because of the slackening California Current, the resulting diatom blooms are smaller by several orders of magnitude than those observed when the flow of the current is strong. This influx of subtropical water into the region is reflected in positive anomalies of temperature, salinity, and sea level.
1400-Million-Year-Old Shale-Facies Microbiota from the Lower Belt Supergroup, Montana
Authors: Horodyski Robert J. , Bloeser Bonnie
Published: October 2006

Carbonaceous shales of the Middle Proterozoic Newland Limestone, Belt Supergroup, Little Belt Mountains, Montana, contain abundant and well-preserved filamentous and spheroidal microfossils. The filamentous forms, ranging from less than 1 to 12 micrometers in width, are interpreted as representing the preserved sheaths of at least four species of nostocalean cyanophytes. The spheroidal forms, ranging from 15 to 108 micrometers in size, are evidently planktonic forms and are tentatively interpreted as representing the encystment stage of eukaryotic algae. The Newland microbiota is adaptable to petrographic thin-section work, and useful for evaluating the potential of such microfossils for intercontinental biostratigraphic correlation. It is the oldest shale-facies microbiota presently known from North America.
Methylation of Humic Acid Fractions
Authors: Wershaw R. L. , Pinckney D. J.
Published: October 2006

A new three-step permethylation procedure for humic acid fractions has been developed. In the first step, carboxylic acid groups are methylated with diazomethane in dimethylformamide; in the second step, hydroxyl groups are methylated with methyl iodide and dimethyl sulfinyl carbanion in dimethylformamide; and in the third step, acidic groups hydrolyzed in the earlier steps are methylated with diazomethane. The resulting product is completely soluble in methylene chloride (a high degree of methylation has been achieved).
Sex Ratio of Parental Investment in Colonies of the Social Wasp
Polistes fuscatus
Authors: Noonan Katharine M.
Published: October 2006

Field estimates of parental investment in the two sexes in the social paper wasp
Polistes fuscatus
indicate that the mother's interests, rather than those of her worker offspring, are realized. Local competition for mates seemed to be absent, and the population investment ratio was not significantly different from 1:1. Workers are not more closely related to the brood they tend than they would be to their own offspring. The 3/4 relationship between sisters in haplodiploid species cannot account for the maintenance of eusociality in this case.
Particle-Mediated Membrane Uptake of Chemical Carcinogens Studied by Fluorescence Spectroscopy
Authors: Lakowicz J. R. , McNamara M. , Steenson L.
Published: October 2006

The fluorescence emissions of chrysene,
N
-ethylcarbazole, and 1,6-diphenylhexatriene undergo large spectral shifts or changes in quantum yield, or both, upon their uptake from particulates by phospholipid vesicles. This membrane uptake of carcinogen and carcinogen-like molecules by model membranes does not result in any disruption of the lipid bilayers. The fluorescence emission of chrysene, when bound to silica, was found to be sensitive to the surface density of chrysene on the silica. These observations demonstrate the feasibility of using fluorescence spectroscopy to measure the rates of exchange of carcinogens from particulate matter to cell membranes and to characterize the surface distribution of chemical carcinogens on particulate matter. Comparison of the uptake rate of chrysene from the unperturbed crystal state, sonicated crystals, and the silica-adsorbed state demonstrates that the last condition results in the most rapid transport of chrysene into model membranes. This information should prove valuable in understanding the cocarcinogenic effects of particulates and polynuclear aromatic hydrocarbons.
Wear of Unsound Pebbles in River Headwaters
Authors: Adams John
Published: October 2006

Pebbles that are initially weathered, inhomogeneous, angular, or fractured ("unsound") become sound with transport. The Sternberg law describes well the wear of sound pebbles found in large rivers, but describes poorly that of unsound pebbles in river headwaters. For unsound pebbles the Sternberg coefficient (which is assumed to be a constant) decreases appreciably downstream. An alternative to the Sternberg law is derived in which the coefficient is proportional to the reciprocal of the downstream distance traveled. The laws are compared by using data from the Clutha basin in New Zealand.
Preliminary Results of the Solar Flux Radiometer Experiment Aboard the Pioneer Venus Multiprobe Mission
Authors: Tomasko M. G. , Doose L. R. , Palmer J. , Holmes A. , Wolfe W. , Castillo N. D. , Smith P. H.
Published: October 2006

The solar flux radiometer aboard the Pioneer Venus large probe operated successfully during its descent through the atmosphere of Venus. Upward, downward, and net fluxes from 0.4 to 1.0 micrometers were obtained at more than 390 levels between 185 millibars (at an altitude of ∼61 kilometers) and the surface. Fluxes from 0.4 to 1.8 micrometers were also obtained between 185 millibars and about the level at which the pressure was 2 atmospheres. Data from 80 to 185 millibars should be available after additional decoding by the Deep Space Network. Upward and downward intensities in a narrower band from 0.59 to 0.66 micrometers were also obtained throughout the descent in order to constrain cloud properties. The measurements indicate three cloud regions above the 1.3-atmosphere level (at an altitude of ∼49 kilometers) and a clear atmosphere beneath that level. At the 67° solar zenith of the probe entry site, some 15 watts per square meter are absorbed at the surface by a dark ground, which implies that about 2 percent of the solar energy incident on the planet is absorbed at the ground.
One Mars Year: Viking Lander Imaging Observations
Authors: Jones Kenneth L. , Arvidson Raymond E. , Guinness Edward A. , Bragg Susan L. , Wall Stephen D. , Carlston Carl E. , Pidek Deborah G.
Published: October 2006

Throughout the complete Mars year during which they have been on the planet, the imaging systems aboard the two Viking landers have documented a variety of surface changes. Surface condensates, consisting of both solid H
2
O and CO
2
, formed at the Viking 2 lander site during the winter. Additional observations suggest that surface erosion rates due to dust redistribution may be substantially less than those predicted on the basis of pre-Viking observations. The Viking 1 lander will continue to acquire and transmit a predetermined sequence of imaging and meteorology data as long as it is operative.
Voyager Telecommunications: The Broadcast from Jupiter
Authors: Edelson Robert E. , Madsen Boyd D. , Davis Esker K. , Garrison Glenn W.
Published: October 2006

Sweeping past Jupiter, the Voyager 1 spacecraft presages a new era in the exploration of the solar system. Not since the TV return from Apollo has a spacecraft returned information of such volume and pictures of such startling clarity. Yet this feat was accomplished from a distance 1770 times as great as that of the lunar adventure. The communication system responsible for this remarkable achievement is a compilation of elements ranging from tiny integrated circuits to enormous ground antennas. This article seeks to describe the way in which data are returned from these fascinating, faraway bodies and to convey the excitement of the engineering work that supports our scientific endeavors.
Thermal Structure and Energy Influx to the Day-and Nightside Venus Ionosphere
Authors: Knudsen W. C. , Spenner K. , Whitten R. C. , Spreiter J. R. , Miller K. L. , Novak V.
Published: October 2006

Pioneer Venus in situ measurements made with the retarding potential analyzer reveal strong variations in the nightside ionospheric plasma density from location to location in some orbits and from orbit to orbit. The ionopause is evident at night as a relatively abrupt decrease in the thermal plasma concentration from a few hundred to ten or fewer ions per cubic centimeter. The nightside ion and electron temperatures above an altitude of 250 kilometers, within the ionosphere and away from the terminator, are comparable in magnitude and have a value at the ionopause of approximately 8000 K. The electron temperature increases from a few tens of thousands of degrees Kelvin just outside the ionopause to several hundreds of thousands of degrees Kelvin further into the shocked solar wind. The coldest ion temperatures measured at an altitude of about 145 kilometers are 140 to 150 K and are still evidently above the neutral temperature. Preliminary day- and nightside model ion and electron temperature height profiles are compared with measured profiles. To raise the model ion temperature to the measured ion temperature on both day- and nightsides, it was necessary to include an ion energy source of the order of 4 × 10
–3
erg per square centimeter per second, presumably Joule heating. The heat flux through the electron gas from the solar wind into the neutral atmosphere averaged over day and night may be as large as 0.05 erg per square centimeter per second. Integrated over the planet surface, this heat flux represents one-tenth of the solar wind energy expended in drag on the sunward ionopause hemisphere.
Vibrations: Their Signal Function for a Spider Kleptoparasite
Authors: Vollrath Fritz
Published: October 2006

The stealing behavior of
Argyrodes elevatus
suggests that this kleptoparasitic spider monitors the movements and the hunting success of its web-building host. Wrapping of prey by the host regularly elicits raids from the kleptoparasite. The prey-catching activities of the host generate vibrations that were recorded with a position-sensing photodiode. The recordings indicated that wrapping movements produce a characteristic pattern of vibrations.
Solid-State Photoelectron Spectroscopy with Synchrotron Radiation
Authors: Weaver John H. , Margaritondo Giorgio
Published: October 2006

Synchrotron radiation sources, providing intense, tunable, polarized, and stable beams of ultraviolet and x-ray photons, are having a great impact on biology, physics, chemistry, materials science, and other areas of research. Synchrotron radiation has revolutionized solid-state photoelectron spectroscopy by enhancing its capabilities for investigating the electronic behavior of solids and solid surfaces. Several fundamental photoemission techniques that rely on synchrotron radiation are discussed in this article. These techniques have an adjustable tunable surface sensitivity and provide the first direct mapping of the electronic band structure. Recent applications of photoelectron spectroscopy for studies of chemisorption geometries and surface structures are discussed.