bluuebunny/crossref_metadata_2025 huggingface dataset:
Lunar Surface Strength: Implications of Luna 9 Landing
Authors: Jaffe L. D. , Scott R. F.
Published: October 2006

The ability of the lunar surface to support statically the Luna 9 capsule indicates that the surface can bear at least 5 × 10
3
dyne per square centimeter (10
-1
lb/in.
2
). Analysis of the landing dynamics, using available data, gives a lower bound of about 1 to 2 × 10
5
dyne/cm
2
, but this estimate may not be conservative because of uncertainties regarding the shock-absorbing system used and the direction of the velocity vector at impact.
Stimulus Control in Pigeons Based on Proprioceptive Stimuli from Floor Inclination
Authors: Riccio David C. , Urda Michael , Thomas David R.
Published: October 2006

Two groups of pigeons trained to peck a dimly illuminated disc in an otherwise dark experimental chamber with the floor horizontal (0° tilt) or inclined 30° to the left, respectively, show decremental generalization gradients of response rate when the floor inclination is varied from its training position. Discrimination training in which food reinforcement is available under one floor tilt condition but not under another steepens the slope of such gradients. In a second experiment, pigeons reinforced for pecking when the floor was tilted 10° or 20° and not reinforced under the alternative condition showed steep gradients with maximal responding displaced from the reinforced stimulus.
Cesium-137 Body Burdens in Alaskan Eskimos during the Summer of 1965
Authors: Hanson Wayne C.
Published: October 2006

Cesium-137 body burdens of Anaktuvuk Pass, Alaska, residents during the summer of 1965 were about 30 percent less than during 1964. Lower amounts of cesium-137 in the people reflected a similar decrease of this isotope in caribou flesh, which serves as the principal food of the natives.
Dormancy Regulation in Peach Seeds
Authors: Lipe William N. , Crane Julian C.
Published: October 2006

An inhibitor of seed germination was isolated from the integuments of Lovell peach seeds. Evidence from chromatographic analysis, from studies of its absorption of ultraviolet light and from assays on its effects on plant growth, indicate that the inhibitor is, if not identical with, dormin. Termination of rest in peach seeds is correlated with the disappearance of the inhibitor. The effects of the inhibitor are antagonistic to those of gibberellic acid on sections of wheat coleoptiles.
Acrylonitrile Polymerization in a Miniaturized High-Pressure Optical Cell
Authors: Zhulin V. M. , Lippincott Ellis R. , Bailey William J.
Published: October 2006

A miniaturized high-pressure optical cell has been used to investigate the feasibility of carrying out high-pressure polymerization, wherein the process can be observed both spectroscopically and optically while the polymerization process is occurring. The method has been illustrated by a novel polymerization of acrylonitrile.
Inheritance of Reactivity to Experimental Manipulation in Mice
Authors: Henderson Norman D.
Published: October 2006

The mode of inheritance of open-field defecation was found to differ according to earlier treatment of the mice. Activity of hybrids, however, was closer to that of the less active parent for all conditions of pretreatment. These results suggest that adequate sampling not only of gene pools, but also of both pretest and test environments, is necessary before statements concerning effects of prior treatment, or mode of inheritance of specific behavior, are valid.
Mars: New Absorption Bands in the Spectrum
Authors: Connes Janine , Connes Pierre , Kaplan Lewis D.
Published: October 2006

New absorption bands have been found in the near-infrared spectrum of Mars by Fourier spectroscopy. They are tentatively identified in part as due to reduced gases in the Martian atmosphere.
Continuity of Protein Synthesis Through Cleavage Metaphase
Authors: Gross P. R. , Fry B. J.
Published: October 2006

Protein synthesis continues without a decline in rate throughout the period of chromosome condensation and of cytokinesis in the first two cleavages of sea urchin embryos. The natural synchrony of the egg populations and the conditions of measurement allowed even a partial inhibition of synthesis to be observed. Our results do not explain the mechanism of inhibition of protein synthesis that occurs at metaphase in cultured mammalian cells, but it shows that such a change in rate is neither universal nor obligatory.
End-Organ Effects of Thyroid Hormones: Subcellular Interactions in Cultured Cells
Authors: Siegel Edward , Tobias Cornelius A.
Published: October 2006

Both actinomycin D and puromycin suppress the formation of colonies by cultured human kidney epithelial cells (T-1), but inactivation by puromycin is partially reversed with thyroid hormones. Uptake by the cells of L-thyroxine labeled with iodine-125, 60 to 80 percent of which is nuclear, is depressed by actinomycin and enhanced by puromycin. Genome and possibly nuclear membrane are implicated as initiating loci.
Terminology of Cell-Water Relations
Authors: Kramer Paul J. , Knipling Edward B. , Miller Lee N.
Published: October 2006

Use of the term "water potential" in place of "diffusion pressure deficit" would improve communication between botanists and scientists in other fields because the concept of potential is familiar to most scientists. Water potential, expressed as ψ

w

, is the difference in free energy or chemical potential per unit molal volume between pure water and water in cells at the same temperature. The potential of pure water is set at zero; hence the potential of water in cells and solutions is less than zero, or negative. The water potential of a cell is numerically equal to its diffusion pressure deficit, but has a negative sign.
Stokes Parameters for 1665-Megacycles-per-second Emission from OH near Source W3
Authors: Meeks M. L. , Ball J. A. , Carter J. C. , Ingalls R. P.
Published: October 2006

The Stokes parameters were measured as a function of frequency for the anomalous 1665-megacycles-per-second OH emission originating near the thermal radio source W3. The emission is highly polarized, and the polarization parameters vary rapidly with frequency. The observed polarization can be described in terms of narrow, roughly Gaussian, emission features, all with uniform polarization but with several features overlapping without coherence near the center of the spectrum. Most of the individual features may be 100-percent polarized. Detailed examination of the brightest features suggest that they are not exactly Gaussian in shape.
Submarine Lithification of Carbonate Sediments
Authors: Milliman John D.
Published: October 2006

Recrystallized planktonic limestones from two guyots in the North Atlantic are in oxygen-isotopic equilibrium with their present ambient waters, suggesting submarine lithification and recrystallization. The early stages of submarine lithification of carbonates may involve precipitation of, and replacement by, magnesium-rich calcite; with time this may invert to magnesium-poor calcite. This type of lithification probably requires very low rates of sediment accumulation.
Glycogen Content in the Wood-Boring Isopod,
Limnoria lignorum
Authors: George R. Y.
Published: October 2006

The glycogen content of the isopod,
Limnoria lignorum
, ranges from 2.01 to 3.44 percent of its dry weight. Starvation of the animal for 1 week results in a decrease of the glycogen content by about 68 percent. Measurements of its oxygen consumption indicate that sufficient carbohydrate, probably its sole source of energy, is oxidized daily to meet the carbon requirements. The infestation zone of
Limnoria
is restricted to the surface of submerged wood, since this isopod borer, unlike the molluscan borers, does not have a glycogen reserve sufficient to meet prolonged periods of anaerobiosis.
Antiserum to Lymphocytes: Prolonged Survival of Canine Renal Allografts
Authors: Monaco Anthony P. , Abbott William M. , Othersen H. Biemann , Simmons Richard L. , Wood Mary L. , Flax Martin H. , Russell Paul S.
Published: October 2006

A horse immunized with dog lymphocytes produced an antiserum which agglutinated canine lymphocytes in vitro and caused prolonged lymphopenia in dogs in vivo. Renal transplants in dogs treated with this antiserum survived for long periods, two of the grafts surviving beyond 350 days with normal function and histologic appearance.
Crystal and Molecular Structure of Acetylselenocholine Iodide
Authors: Shefter Eli , Kennard Olga
Published: October 2006

The structure of acetylselenocholine iodide has been determined by x-ray crystallographic analysis. The molecule is in the trans conformation about the C—C bond of the choline residue. This conformation appears to explain the molecule's inability to give a positive cholinergic response when added to an electroplax preparation.
Peafowl Lactate Dehydrogenase: Problem of Isoenzyme Identification
Authors: Rose Richard G. , Wilson Allan C.
Published: October 2006

Peafowl, like other vertebrates, contain multiple forms of lactate dehydrogenase. The electrophoretic properties of the peafowl isoenzymes are unusual in that the isoenzyme from heart tissue can be either more or less anodic than that of muscle, depending on the
p
H. This finding focuses attention on the problem of isoenzyme identification. It is suggested that isoenzymes be identified on the basis of properties that are chemically and biologically more significant than electrophoretic mobility.
Cell Size and Rate of Protein Synthesis in Ventral Horn Neurones
Authors: Peterson R. Price
Published: October 2006

Autoradiographic studies show that small ventral horn neurones synthesize protein at a greater rate per unit area of cytoplasm than do large ones. It is suggested that this is related to the faster rate of firing of the smaller neurones.
Intranuclear Microtubules
Authors: Behnke O. , Forer Arthur
Published: October 2006

Intranuclear microtubules are a regular feature of spermatocyte meiosis in a crane fly (
Nephrotoma suturalis
Loew).
Nature of Seed Dormancy in
Phacelia tanacetifolia
Authors: Chen Shepley S. C. , Thimann Kenneth V.
Published: October 2006

The inhibiting effect of light on germination of
Phacelia tanacetifolia
seed is overcome by removing the tip of the endosperm; however, immersion in solutions of high osmotic pressure reinstates the light sensitivity. Inhibition of germination by high temperature behaves similarly. Dormancy is ascribed to balance between mechanical constraint by the endosperm and "expansive force" of the embryo.
Spontaneous Mammary Tumors: Decrease of Incidence in Mice Infected with an Enzyme-Elevafing Virus
Authors: Riley Vernon
Published: October 2006

Mice infected with a virus which causes increased activity of lactate dehydrogenase, and of other enzymes in blood plasma, had a significantly lower incidence of spontaneous mammary carcinoma than did controls. When the experiment was terminated at 18 months, the incidence of mammary tumors in controls was 90 percent, and in infected mice, 53 percent.
Restoration of Photographs by Neutron Activation
Authors: Ostroff Eugene
Published: October 2006

Badly faded or stained photographs or radiographs, negative or positive, can be restored by use of neutron activation and autoradiography, provided that at least a trace of image silver is present and that the picture is relatively free of halogens and other silver.
A Disulfide-Linked Collagenous Protein of Nematocyst Capsules
Authors: Blanquet Richard , Lenhoff Howard M.
Published: October 2006

The major protein component present in the capsule and thread of a sea anemone nematocyst consists of monomers of a collagen-like protein linked by disulfide bonds. Purified nematocyst capsules and threads are rich in hydroxyproline, and dissolved by disulfide reducing agents. Electrophoresis of the dissolved component on acrylamide gel results in a single detectable protein band.
Atomic Nuclei: Moments of Inertia and Quadrupole Moments
Authors: Strnad J.
Published: October 2006

Moments of inertia and quadrupole moments of deformed even-even nuclei were calculated in the closely packed spheron model.
Fossil Occurrence of Murine Rodent (
Nesokia indica
) in the Sudan
Authors: Robinson Peter
Published: October 2006

A specimen of the murid rodent
Nesokia indica
has been recovered from a late Paleolithic archeological site in the Sudan. This is a range 1200 km south of the site of any known occurrences, and it indicates a different environment near the Nile River than that which exists at the present time. The late Paleolithic water table is inferred to have been more stable, allowing for permanent moist soil.
Protein Synthesis by Heart Muscle Ribosomes: An Effect of Insulin Independent of Substrate Transport
Authors: Stirewalt William S. , Wool Ira G.
Published: October 2006

Ribosomes from heart muscle of diabetic animals perfused for 15 minutes with insulin, but without added substrate, were more active in the catalysis of protein synthesis than were ribosomes from hearts perfused without insulin. This effect of insulin on the efficiency of protein synthesis seems not to result from transport of some critical substrate into muscle, nor is the effect on ribosomes mediated by a product of a tissue other than muscle.
Rheumatic-like Cardiac Lesions in Mice
Authors: Cromartie William J. , Craddock John G.
Published: October 2006

A single intraperitoneal injection of a sterile extract of sonically disrupted group A streptococcal cells induced an inflammatory process in the hearts of mice. The cardiac lesions, in terms of their distribution and histological features, are similar to the cardiac lesions of rheumatic fever.
Stylet-Borne Virus: Active Probing by Aphids Not Required for Acquisition
Authors: Barnett Charles B. , Pirone Thomas P.
Published: October 2006

Anesthetized aphids, whose stylets had been dipped into capillaries containing purified concentrated cucumber mosaic virus, acquired the virus and, after recovery from the anesthetic, were able to transmit it in a low percentage of cases. Although this study does not eliminate active probing as a means of virus acquisition, experimentally, it clearly establishes passive contamination of aphid mouthparts as a method of virus acquisition.
Light Chains of Mouse Myeloma Proteins: Partial Amino Acid Sequence
Authors: Perham Richard , Appella Ettore , Potter Michael
Published: October 2006

Five kappa chains in the urinary proteins of the BALB/c mouse have the same carboxyl terminal amino acid sequence; this sequence resembles that of kappa light chains in human immunoglobulins. The five chains have amino acid sequence variations at the amino-terminal. The genetic basis for the amino-terminal variations is not understood but could be due either to a mechanism for differently translating a single genetic message or to the presence of more than one kappa-type structural cistron in the BALB/c genome.
Denitrification Rates in an Island Bay in the Equatorial Pacific Ocean
Authors: Goering J. J. , Dugdale R. C.
Published: October 2006

Experimental data show that
15
N-labeled nitrate can be converted to molecular nitrogen in sea water containing little or no oxygen. The process is presumed to be biochemical. No evidence of the reaction was found in the water of the Peru current, which is low in oxygen but high in nitrite.
Shattuckite and Planchéite: A Crystal Chemical Study
Authors: Evans Howard T. , Mrose Mary E.
Published: October 2006

The orthorhombic crystal structures of shattuckite, Cu
5
(SiO
3
)
4
(OH)
2
and planchéite, Cu
8
(Si
4
O
11
)
2
(OH)
4
⋅ H
2
O, have been solved. Shattuckite contains silicate chains similar to pyroxene in a complex association with copper atoms, while the closely related planchéite contains silicate chains similar to amphibole.
Release of Catecholamines and Specific Protein from Adrenal Glands
Authors: Kirshner Norman , Sage Harvey J. , Smith W. James , Kirshner Annette G.
Published: October 2006

Rabbit antiserums directed against a purified protein obtained from the catecholamine storage vesicles of the adrenal medulla of the cow were used to study the mechanism of secretion from the adrenal medulla. During secretion evoked by acetylcholine in isolated perfused adrenal glands, catecholamines and the specific intravesicular protein were released in relative amounts comparable to those present in the intact gland. Thus catecholamines are apparently released from the storage vesicles by a process resembling reverse pinocytosis.
Underwater Vocalization by Sea Lions: Social and Mirror Stimuli
Authors: Schusterman Ronald J. , Gentry Roger , Schmook James
Published: October 2006

Underwater vocal response of three sea lions (
Zalophus californianus
) increased under conditions of social interaction. When confronted by their mirror images, two animals increased their number of vocalizations, which included "whinny" sounds, barks, buzzing, and varying patterns of click trains. Click vocalizations showed habituation and recovery when the animals were in the presence of the mirror stimulus.
Thyrocalcitonin: Ultracentrifugation in Gradients of Sucrose
Authors: O'Riordan J. L. H. , Tashjian A. H. , Munson P. L. , Condliffe P. G. , Aurbach G. D.
Published: October 2006

Analysis of thyrocalcitonin, by density-gradient ultracentrifugation at high speed, showed that its molecular weight (5000 to 6000) is considerably less than was heretofore recognized.
Ultrasonic Sensitivity: A Tympanal Receptor in the Green Lace Wing
Chrysopa carnea
Authors: Miller Lee A. , Macleod Ellis G.
Published: October 2006

Chrysopa carnea
can perceive ultrasonic frequencies up to at least 100 kilohertz modulated at pulse repetition rates as rapid as 150 per second. The receptor sites are a bilateral pair of small swellings in a vein of the fore wings.
Nucleohistone Dissociation by Ganglioside Micelles
Authors: Meisler Miriam H. , McCluer Robert H.
Published: October 2006

The sialic acid-containing glycosphingolipids known as gangliosides can reverse the heat stabilization of DNA by histones. The ability of pure mono- and disialogangliosides to dissociate reconstituted nucleohistone is directly dependent on their sialic acid content; they are effective in concentrations above their critical micelle concentration.
Substructure of Certain Cytoplasmic Microtubules: An Electron Microscopic Study
Authors: Burton Paul R.
Published: October 2006

Negatively stained cytoplasmic microtubules of lung-fluke sperm show a helical structure that is not found in peripheral doublet tubules of axial units. In transverse sections, the wall of such microtubules appears to comprise about eight subunits.
Lipolysis in Homogenates of Adipose Tissue: An Inhibitor Found in Fat from Obese Rats
Authors: Haessler Herbert A. , Crawford John D.
Published: October 2006

The presence of a lipid-bound inhibitor in adipose tissue of rats with hypothalamic obesity may explain the failure of the tissue to release fatty acids on epinephrine stimulation. Aqueous extracts of tissue from obese animals showed no deficiency of lipase activity, but when whole homogenates of epididymal fat from lean and obese animals were mixed, 25 percent tissue from obese animals reduced by 73 percent the release expected from tissue of lean controls.
Comparative Mutagenicity of Two Chemosterilants, Tepa and Hempa, in Sperm of
Bracon hebetor
Authors: Palmquist Jeanette , LaChance Leo E.
Published: October 2006

In an assessment of the mutagenic efficiency of the alkylating agent, tepa, and its nonalkylating analog, hempa, both chemicals induced a high frequency of recessive lethal mutations in the sperm of the parasitic wasp,
Bracon hebetor
Say (
Habrobracon
), although tepa was the more efficient mutagen.
Energy Spectra of a Number of Celestial X-Ray Sources in the Energy Range from 2 to 60 Kiloelectron Volts
Authors: McCracken K. G.
Published: October 2006

The emission of 20 to 60 kev x-rays by an astronomical object in the constellation of Cygnus has been observed with a balloon-borne x-ray telescope flown from Hyderabad, India. The balloon data, used in conjunction with data pertaining to the flux in the wavelength range from 2 to 10 Å can be fitted by a power law in photon energy varying as (
h
ν
)
-1.7
. The Cygnus object is the brightest object in the sky in the hard x-ray wavelength range and has the hardest spectrum of all observed objects that emit x-rays. The astronomical object should be capable of accelerating protons up to energies of the order of 10
18
electron volts. Upper limits to the hard x-ray fluxes from Sco XR-1, Cyg XR-2, Oph XR-1, and Ser XR-1 are established; it is shown that the Sco XR-1 spectrum is very soft.
Crystal Structure of the Zeolite Paulingite
Authors: Gordon E. Kent , Samson Sten , Kamb W. Barclay
Published: October 2006

Paulingite, a zeolite, has a framework structure consisting of 2016 atoms (672 silicon or aluminum and 1344 oxygen) which are in a cubic cell with an edge of length 35.093 Å. The framework has several features in common with the synthetic zeolites Linde A and ZK-5; the main channels are of similar size. We have also located most of the cations and water molecules inside the frame-work.
Multiple Gene Loci for the Monomeric Hemoglobin of the Hagfish (
Eptatretus stoutii
)
Authors: Ohno Susumu , Morrison Martin
Published: October 2006

The fact that members of the subclass
Cyclotomata
possess monomeric hemoglobin molecules has been known for some time. Electrophoresis of hemolysates from 12 hagfish (
Eptatretus stoutii
) revealed five hemoglobin phenotypes with four to six distinct zones of hemoglobin. Each zone is believed to represent a monomer containing one heme group on a single polypeptide chain with a molecular weight of approximately 18,000. It is postulated that these monomers are controlled by genes at four loci.
Lithology and Paleontology of the Reflective Layer Horizon A
Authors: Saito Tsunemasa , Burckle Lloyd H. , Ewing Maurice
Published: October 2006

Cores recovered from horizon A are Late Cretaceous (Maestrichtian) in age and consist of alternating layers of calcareous turbidites and "red clay." The presence of red clay suggests that the water depth in this area during Cretaceous time was at least as great as at present—more than 5100 meters. A middle Cretaceous (Cenomanian) core consisting of interbedded sand and gravel and light-to-dark-gray lutite was taken in the same area from a layer stratigraphically below the horizon; the presence of hydrogen sulfide and iron sulfide may indicate anaerobic conditions that may be attributable to local ponding of sediment in Cenomanian time.
Periventricular Cerebral Impedance after Intraventricular Injection of Calcium
Authors: Wang H. H. , Tarby T. J. , Kado R. T. , Adey W. R.
Published: October 2006

Injection of small volumes of calcium solution into the lateral ventricle of the cat was followed by large electrical-impedance changes in gray matter bounding the ventricle, including the caudate nucleus and hippocampus. These changes lasted more than 24 hours and were accompanied by epileptiform electroencephalographic activity. Biweekly injections led to status epilepticus. Injections of similar amounts of magnesium ions were without comparable effects. Possible interactions between calcium ions and intercellular macromolecular material are discussed as a basis for certain impedance shifts in cerebral tissue.
Periodicity of Desert Rodent Activity
Authors: French Norman R. , Maza Bernardo G. , Aschwanden Arnold P.
Published: October 2006

The radiation dose detected by microthermoluminescent dosimeters attached to pocket mice,
Perognathus formosus
, indicated the amount of time these animals were active on the surface of the ground. Radiation was from an elevated, partially shielded source in the center of the 8-hectare enclosure. The rodents are almost entirely inactive in midwinter but spend 30 to 40 percent of their time above ground in the summer months. Periods of activity increase gradually through the spring. These results support laboratory findings that members of this genus undergo periods of torpor in response to low ambient temperatures or food shortage. That this adaptation may enhance survival is indicated by the longevity of marked individuals of a related species.
Deficits in Passive Avoidance and Fear Conditioning in Mice with Septal Lesions
Authors: Slotnick Burton M. , Jarvik Murray E.
Published: October 2006

By means of a simple activity measure, mice with lesions of the septal forebrain were tested for passive avoidance (response inhibition) and fear conditioning. In two separate experiments animals with septal lesions showed little or no conditioning, as evidenced by lack of suppression of activity during and following activity-contingent foot shock. Results support and extend the hypothesis that these deficits in passive avoidance derive from the removal of normal inhibitory influences mediated by the septal area.
Newberyite in Ancient and Modern Urinary Calculi: Identification and Space Group
Authors: Lonsdale Kathleen , Sutor D. June
Published: October 2006

Relatively large amounts of newberyite, MgHPO
4
⋅3H
2
O, are found in old or very large urinary calculi. Single crystals of struvite, MgNH
4
PO
4
⋅6H
2
O, sometimes show some decomposition to newberyite on aging. The fact that large amounts of struvite are also found in ancient stones implies, however, that special conditions, as yet unknown, are required for decay to occur.
Feedback of Speech Muscle Activity during Silent Reading: Rapid Extinction
Authors: Hardyck Curtis D. , Petrinovich Lewis F. , Ellsworth Delbert W.
Published: October 2006

Surface electromyograms of the laryngeal muscles were made while subjects read silently. Those who showed an increase in electrical activity over that at relaxation were provided with auditory feedback of the muscle activity. This treatment resulted in immediate and long-lasting cessation of the subvocalization. This method should prove valuable in treating some reading problems.
Brain Sensitivity to Alcohol in Inbred Mouse Strains
Authors: Kakihana Ryoko , Brown David R. , McClearn Gerald E. , Tabershaw Irving R.
Published: October 2006

The voluntary selection of aqueous ethanol in preference to water has been studied in a number of animal species. A pharmacological phenomenon observed in all species, including humans, is depression of the central nervous system which eventually leads to "sleep." The sleeping time at a given concentration of alcohol in the brain depends on strain sensitivity.
Lactate Dehydrogenase Activity: Effect in vitro of Some Pesticidal Chemicals
Authors: Sova Carl R.
Published: October 2006

The effect of chlorinated hydrocarbon insecticides upon rabbit-muscle lactate dehydrogenase was determined by both the direct determination of diphosphopyridine nucleotide reduction and a tetrazolium salt reduction method. A comparison of the two assay procedures revealed that the pronounced stimulation of lactate dehydrogenase LDH activity was noted with the tetrazolium salt method but could not be detected with a direct photometric determination method. Incubation of lactate dehydrogenase with DDT or heptachlor prior to the addition of either diphosphopyridine nucleotide or substrate resulted in a complete inhibition of enzyme activity. The inclusion of either diphosphopyridine nucleotide or substrate in the prior incubation mixtures afforded no protection to the enzyme.
Geographic Variation in Ovarian Cycles and Clutch Size in
Cnemidophorus tigris
(Teildae)
Authors: McCoy C. J. , Hoddenbach G. A.
Published: October 2006

Ovarian cycles and individual reproductive potentials of
Cnemidophorus tigris
in Colorado and Texas were studied by counts and measurements of yolked ovarian follicles, corpora lutea, and oviducal eggs. Colorado lizards lay one clutch averaging 3.4 eggs annually between May and August; Texas lizards average two clutches, each averaging 2.2 eggs, between April and mid-August.
Discrimination Learning and Inhibition
Authors: Terrace H. S.
Published: October 2006

Pigeons learned to discriminate between a white vertical line on a dark background (S+) and a monochromatic circle of light (S—) either with or without responses to S— (errors). Gradients of inhibition, which were centered around S—, and which had greater than zero slopes, were obtained only from those subjects who learned to discriminate with errors. The results indicate that the occurrence of errors is a necessary condition for S— to function as an inhibitory stimulus. This finding is consistent with other performance differences in subjects who have learned to discriminate with and without errors.
Evoked Pressure Responses in the Rabbit Eye
Authors: Collins Carter Compton
Published: October 2006

In the rabbit, a sensory stimulus of low intensity evokes a characteristic transient intraocular rise in pressure with an amplitude as great as 10 millimeters of mercury. This α-adrenergically mediated phenomenon occurs concomitantly with a general arousal response and appears to be caused by contraction of the orbital smooth muscle of Müller.
Biosynthesis of DNA by Isolated Mitochondria: Incorporation of Thymidine Triphosphate-2-C
14
Authors: Parsons Peter , Simpson Melvin V.
Published: October 2006

Thymidine triphosphate-2-C
14
and other deoxynucleoside triphosphates are incorporated into the DNA of isolated mitochondria from rat liver cells. The reaction is partially dependent on the other deoxynucleoside triphosphates and proceeds in the virtual absence of bacteria. The product has the properties of mitochondrial rather than nuclear DNA, and end-group studies indicate labeling of the interior of the molecule.
Transfer Following Operant Conditioning in the Curarized Dog
Authors: Black A. H.
Published: October 2006

Dogs were trained to press a pedal to avoid shock. They were then operantly reinforced for making or for refraining from making a series of electromyographic responses while almost completely curarized. Tests after recovery from curarization showed that operant conditioning under curare influenced the original pedal-press response.
Deuterium Isotope Effect on Carbon Isotope Fractionation in Photosynthesis
Authors: Uphaus Robert A. , Katz Joseph J.
Published: October 2006

Plants grown in D
2
O show a decreased tendency to fractionate carbon-13 during photosynthetic incorporation of carbon dioxide. The isotopic ratio C
13
/C
12
of the tissues of deuterated plants appears to be proportional to the deuterium content of the tissue. This effect was found in specimens of the partially deuterated vascular plant
Nicotiana tabacum
as well as in cultures of the fully deuterated alga
Chlorella vulgaris
.
Phenotypic Variations among Chloroplasts of a Single Cell
Authors: Gibor Aharon
Published: October 2006

Some normal-looking chloroplasts of a
Nitella
cell do not incorporate carbon dioxide into substances insoluble in cold acid. The distribution of such chloroplasts among the rows of normal organelles indicates that the defect is not due to a genetic mutation but probably represents a physiological stage in the development of the organelles.
Aluminum-26 in Pacific Sediment: Implications
Authors: Wasson John T. , Alder B. , Oeschger H.
Published: October 2006

Aluminum-26 has been detected in a sample of sediment from the South Pacific. The
disintegration rate of 0.8 disintegration per minute per kilogram of dry sediment is
considerably higher than that expected from cosmic-ray spallation of atmospheric argon; it
appears to result mainly from accretion of activity induced in interplanetary dust by
solar-flare particles. This finding is in keeping with Wasson's published estimates
regarding the magnitude of this effect, and confirms the order-of-magnitude correctness of
the solar-particle flux and terrestrial accretion rate of interplanetary dust used in that
calculation.
Search for 21-Centimeter Radiation near Cosmic X-Ray Sources
Authors: Hobbs R. W. , Hollinger J. P.
Published: October 2006

A search was made for 21-centimeter wavelength radiation in the regions of seven of the cosmic x-ray sources. No new sources with flux densities greater than 5.5 flux units were found.
Crayfish Muscle Fiber: Ionic Requirements for Depolarizing Synaptic Electrogenesis
Authors: Ozeki Masahiro , Grundfest Harry
Published: October 2006

Presence of sodium in the bathing medium is not essential for the electrically excitable depolarizing electrogenesis of crayfish muscle fibers, production of action potentials being dependent on calcium. The depolarizing electrogenesis of the excitatory synaptic membrane component does require sodium, however, and this ion cannot be replaced by lithium as it can in spike electrogenesis of many cells. Ionophoretic applications of glutamate, which in the presence of sodium depolarize the cell by activating the excitatory synaptic membrane, are without effect in the absence of sodium. Not only is there no depolarization, but the membrane conductance also remains unchanged. Thus, in the absence of inward movement of sodium across the synaptic membrane there is also no outward movement of potassium. Accordingly, it seems that increased conductance for potassium is not an independent process in the synaptic membrane, whereas it is independent of sodium activation in spike electrogenesis. Chloride activation is independent, however; increase in conductance and the electrogenesis of the inhibitory synaptic component are not affected by the absence of sodium. Implications of these findings regarding the structure of differently excitable membrane components are discussed.
Molluscan Faunal Changes around Bermuda
Authors: Abbott R. Tucker , Jensen Russell
Published: October 2006

The recent appearance of large populations of certain adult marine mollusks in Bermuda shallows, unreported in previous surveys, suggests that an invasion is taking place, probably from Florida or the Bahamas, or from both. "Newcomers" grow to sizes larger than any known elsewhere, suggesting that the characteristically large sizes of some species in Bermuda reflect environmental rather than genetic causes.
Honey Bees: Do They Use the Direction Information Contained in Their Dance Maneuver?
Authors: Johnson Dennis L.
Published: October 2006

Direction communication experiments, when controlled against unilateral visitation of trained foragers at the experimental site, exhibited no evidence supporting the precision of communication suggested in the dance "language" hypothesis. Results compare well with those which might be expected on the basis of the geometric arrangement of the feeding dishes.
American Jurassic Symmetrodonts and Rhaetic "Pantotheres"
Authors: Crompton A. W. , Jenkins F. A.
Published: October 2006

The molar morphology of the symmetrodonts
Tinodon
and
Eurylambda
from the late Jurassic of North America is virtually identical to that of so-called "pantotheres" from the Rhaetic of Wales. Therefore a primitive symmetrodont molar pattern was probably present in the phylogeny of pantotherian and tribosphenic molars. Occlusion of
Tinodon
and
Eurylambda
produced complex wear facets unlike the simple trigon-trigonid shear surfaces of
Spalacotherium
and
Peralestes
.
Gravity Increase at the South Pole
Authors: Behrendt John C.
Published: October 2006

Measurements made between December 1957 and January 1966 of the gravity difference between the McMurdo Sound pendulum station, which is on bedrock, and the South Pole station, which is on the Antarctic ice sheet, show a gravity increase at the South Pole of 0.11 milligals per year. The most likely hypothesis for the increase is that it was caused by ice flowing downslope across a gravity gradient and by the sinking of the South Pole station as a result of accumulation of ice. An alternate hypothesis that the gravity increase was caused by a decrease in ice thickness, of about 40 centimeters per year, is theoretically possible but is not supported by direct evidence.
Deuterium Oxide: Direct Action on Sympathetic Ganglia Isolated in Culture
Authors: Murray Margaret R. , Benitez Helena H.
Published: October 2006

Immature ganglia from chicks and rodents were maintained as organized, developing cultures for 2 months or more, during which time they were continuously exposed to deuterium oxide in their medium. Observations of the living cell communities with the light microscope indicated that deuteration within viable limits (up to 25 percent) accelerates and increases the growth of sympathetic neurons and favors their repeated subdivision as a very large size is attained, thus inducing them to recapitulate cyclically the early stages of neurogenesis. Living deuterated cells appear more opaque and heteromerous than control neurons; furthermore, electron micrographs reveal an unusual abundance of granular and fibrillar elements in the nuclei of both neurons and supporting cells. Sheaves of complexly organized fibrillar components appear in the neuronal perikaryon; and ribosomes, Golgi elements, and microtubules are conspicuously numerous. Both fine structure and function of these ganglia therefore appear to have been modified directly by action of the deuterium isotope.
Aldolase Reaction with Sugar Diphosphates
Authors: Mehler Alan H. , Cusic Marshall E.
Published: October 2006

Xylulose-, fructose-, and octulose-diphosphates are substrates for rabbit muscle aldolase with essentially identical K
m
values, but they are cleaved at different rates. After treatment with carboxypeptidase, chymotrypsin, or subtilisin, aldolase cleaves all of these substrates at the same (deceased) rate; the modified aldolase preparations are also equally impaired in their ability to catalyze the detritiation of specifically labeled dihydroxyacetone phosphate. These results suggest that aldolase exhibits "induced fit," in which the rate of cleavage is determined by the distance between the sites on the protein to which the two phosphate groups of a substrate are bound. The activity of the modified aldolases is limited by a step involving making or breaking a carbon-hydrogen bond.
Mammalian X-Chromosomes: Change in Patterns of DNA Replication during Embryogenesis
Authors: Hill Richard N. , Yunis Jorge J.
Published: October 2006

One arm of both X-chromosomes in female eight-cell embryos of the golden hamster replicates late in the period of DNA synthesis. Mid-gestation embryos and adult fibroblasts show an increase in late-replicating DNA. Here, one X-chromosome is labeled in one arm; the other is labeled throughout.
Preparation of Submicroscopic Spider Threads for Particle Studies
Authors: Saunders M. J. , Prettyman P. E.
Published: October 2006

Many small spiders produce threads of different diameters, some of which are submicroscopic. When the threads are subjected to an environment of tobacco smoke and then examined microscopically, the invisible threads are manifested as particles in a line with no visible connection. These threads are used to support microscopic water droplets in single-particle scattering experiments.
Leukemia Mortality: Downturn Rates in the United States
Authors: Fraumeni Joseph F. , Miller Robert W.
Published: October 2006

A decline, the first ever observed, has recently occurred in leukemia mortality rates for the white population of the United States between the ages of 1 and 74. Possible explanations include diminished exposure to medical x-rays following the release in the United States and Great Britain in 1956 of widely publicized reports on the biologic effects of ionizing radiation.
Oxidative Phosphorylation in Experimental Bilirubin Encephalopathy
Authors: Diamond Ivan , Schmid Rudi
Published: October 2006

Mitochondria from the whole brain or cerebellum of newborn guinea pigs with experimental bilirubin encephalopathy failed to exhibit uncoupling of oxidative phosphorylation. The pigment concentrations required to initiate uncoupling in vitro are much higher than those found in the brain of neurotoxic animals.
Swimming Sea Anemones of Puget Sound: Swimming of Actinostola New Species in Response to
Stomphia coccinea
Authors: Ross D. M. , Sutton L.
Published: October 2006

Swimming as a response of the sea anemone
Actinostola
new species can be elicited as a result of contact with the submarginal surface of another swimming sea anemone
Stomphia coccinea
. However,
Stomphia
does not swim as a result of contact with
Actinostola
. In all other known respects, swimming is caused in both species by the same stimuli, including certain starfishes, a nudibranch, and electrical stimuli. No agent that causes
Actinostola
to swim has been detected in extracts, rubbings, or dried matter from
Stomphia
.
Competent Chick Ectoderm: Nonspecific Response to RNA
Authors: Hillman Nina , Hillman Ralph
Published: October 2006

Presumptive chick neuroectoderm responds to RNA from brain and heart by forming neural tubes, but it does not respond to liver RNA. This differential response can be correlated with the presence of Folin-positive material in those RNA preparations which elicit the formation of neural structures.
Bud Movement in
Hydra
Authors: Shostak Stanley
Published: October 2006

Buds in
Hydra viridis
moved upward in inverted budding regions although normally buds move downward. Their direction was not influenced by the orientation of the distal part of the bud. Bud movement, it would seem, proceeds independently of distal growth and basal attrition in the parent.
Acetylcholine Receptor: Similarity in Axons and Junctions
Authors: Rosenberg Philip , Mautner Henry G.
Published: October 2006

Sulfur and selenium isologs of benzoylcholine and its tertiary analog differ greatly in their abilities to block the electrical activity of squid axons. Presumably, differences in the biological activities of these compounds can be correlated with differences in their electron distribution. The relative effects on axons parallel those on junctions of the electroplax, suggesting the presence of similar receptors.
Late Pleistocene History of Coniferous Woodland in the Mohave Desert
Authors: Wells Philip V. , Berger Rainer
Published: October 2006

Seventeen ancient wood-rat middens, ranging in radiocarbon age from 7400 to 19,500 years and to older than 40,000 years, have been uncovered in the northeastern, north-central, southeastern, and southwestern sectors of the Mohave Desert. Excellent preservation of macroscopic plant materials (including stems, buds, leaves, fruits, and seeds) enables identification of many plant species growing within the limited foraging range of the sedentary wood rat .

An approximately synchronous zonal differentiation of vegetation in response to a gradient of elevation on limestone in the northeastern Mohave Desert is apparent from the macrofossil evidence, preserved in wood-rat middens and ground-sloth coprolites, covering a time span bracketed by radiocarbon ages of about 9000 and 10,000 years. Xerophilous juniper woodlands descended to an elevation of 1100 meters, some 600 meters below the present lower limit of woodland (1700 meters) in the latitude of Frenchman Flat. But desert or semidesert shrubs coexisted with the woodland trees throughout much of the span of elevation corresponding to the pluvial lowering of the woodland zone, and the more mesophytic phase of pinyon-juniper woodland was evidently confined to montane habitats at elevations above 1500 meters. Joshua trees, accompanied by desert shrubs, prevailed down to about 600 meters at Gypsum Cave, Nevada, but only the shrubs of the existing warm-desert vegetation occurred at 530 meters near Rampart Cave, Arizona .

Pleistocene middens from the southeastern Mohave Desert record a relatively large downward shift of the pinyon-juniper woodland zone, paralleling the remarkably low minimum elevation of the existing woodland zone in that area. The macrofossil evidence speaks for former continuity of the many disjunct stands of woodland vegetation in the Mohave Desert region, at least along the higher divides connecting most of the ranges. However, there is no macrofossil evidence of pluvial continuity of range for the more mesophytic, montane, coniferous-forest zone of ponderosa pine or white fir now occupying islands of relatively mesic environment on the highest mountains of the region. On the contrary, the uneven stocking of the lofty mountains of the Mohave Desert with mesophytic or boreal species and the trend toward endemism suggest a long history of isolation.
Computer-Generated Motion Pictures
Authors: Groves Brenton R.
Published: October 2006

A motion picture of the electromagnetic field pattern of a prolate spheroid antenna was completely produced by an IBM 7094 computer and an SC 4020 microfilm plotter. The technique of illustrating complex mathematical subjects by means of computer pictures should lead to better understanding in electrical engineering.
Disaccharidase: Localization in Hamster Intestine Brush Borders
Authors: Johnson Charles F.
Published: October 2006

Electron microscopy of isolated brush borders from epithelial cells of hamster intestine demonstrates 60-angstrom knobs attached to the lumen surface of the plasma membrane. Digestion with activated papain removes these knobs. Separation and recovery of the knobs and the plasma membrane are possible. The activities of the disaccharidases invertase and maltase reside in the knobs and are not found with the plasma membrane.
Ant Stridulations and Their Synchronization with Abdominal Movement
Authors: Spangler Hayward G.
Published: October 2006

Two techniques for accurately correlating movements with vibrations produced by
Pogonomyrmex occidentalis
show three characteristics of the stridulations: alternation of mean chirp intensity, higher frequencies during the upstroke, and interruption of chirps into distinct pulses. These pulses are produced by briefly stopping the gaster during a chirp.
Thalamic Reticular System and Central Grey: Self-Stimulation
Authors: Cooper R. M. , Taylor L. H.
Published: October 2006

Rats will press a bar that brings about stimulation of midline thalamic reticular, periventricular, and central grey brain regions. In the latter two regions stimulation can also cause pain or fear.
Middle and Late Eocene Mammal Communities: A Major Discrepancy
Authors: Black Craig C.
Published: October 2006

The multituberculate
Parectypodus lovei
has been found in late Eocene rocks in Montana, together with 11 other mammal species similar to those found in the late Eocene Tepee Trail Formation in Wyoming. The multituberculate and six other species are unknown in rocks of equivalent age or of middle Eocene age elsewhere. It is suggested that the known middle Eocene faunas are all taken from a similar ecological situation and do not reflect the true diversity of middle Eocene life. Middle Eocene faunas of different ecological aspect may be recovered from sediments along, and in, the mountain fronts of northwestern Wyoming.
Histones in the Wild-Type and the Anucleolate Mutant of
Xenopus laevis
Authors: Berlowitz Laurence , Birnstiel Max L.
Published: October 2006

A comparison of anucleolate mutant and wild-type tadpoles of
Xenopus laevis
reveals striking differences in histones. In the mutant, synthesis of histone fractions I and IIb is virtually absent and IIa is reduced, while fractions III and IV are significantly increased.
Growth and Sporulation of a Pyrimidine Spore Color Mutant of
Sordaria fimicola
Authors: El-Ani Arif S.
Published: October 2006

A nonautonomous spore color mutant of
Sordaria fimicola
is a pyrimidine auxotroph that produces hyaline nonviable ascospores. Uracil, uridine, and cytidine are more effective growth factors than cytosine and thymine and, in high concentrations, render the mutant self-fertile by inducing the ascospores to resume development and maturation. Crosses with the unlinked arginine nonautonomous spore color mutant
st-59
yielded the double mutant
st-59
pyr
that requires both arginine and a pyrimidine for growth, which indicates a lack of suppression of the pyrimidine requirement by the arginine locus.