bluuebunny/crossref_metadata_2025 huggingface dataset:
Information Delivery and the Sensory Evoked Potential
Authors: Sutton Samuel , Tueting Patricia , Zubin Joseph , John E. R.
Published: October 2006

The waveform of evoked responses recorded from human scalp is not determined solely by the physical eliciting stimulus, but also varies as a function of the effective information provided by the stimulus. There is a positive component whose latency is determined by the point in time at which ambiguity is reduced, and whose shape and amplitude are influenced by whether it is the presence or absence of an external event which delivers the information.
Fibrinopeptide B and Aggregation of Fibrinogen
Authors: Shainoff John R. , Dardik Beatriz N.
Published: October 2006

Removal of fibrinopeptide B from human fibrinogen by reaction with the procoagulant enzyme from copperhead snake venom below 25°C resulted in tight aggregation of the fibrinogen, which, in turn, progressively blocked a concomitant but sluggish release of fibrinopeptide A by the enzyme. When the clots obtained at < 25°C were warmed, they dissociated into soluble aggregates and monomers. Release of fibrinopeptide A then resumed, and a secondary coagulation followed. The aggregation induced by release of fibrinopeptide B itself involves a plasmin-susceptible segment located just distal to B in the Bβ chain of fibrinogen, a segment previously shown to be of little importance in the aggregation induced by release of fibrinopeptide A.
Generation of Neurons and Astrocytes from Isolated Cells of the Adult Mammalian Central Nervous System
Authors: Reynolds Brent A. , Weiss Samuel
Published: October 2006

Neurogenesis in the mammalian central nervous system is believed to end in the period just after birth; in the mouse striatum no new neurons are produced after the first few days after birth. In this study, cells isolated from the striatum of the adult mouse brain were induced to proliferate in vitro by epidermal growth factor. The proliferating cells initially expressed nestin, an intermediate filament found in neuroepithelial stem cells, and subsequently developed the morphology and antigenic properties of neurons and astrocytes. Newly generated cells with neuronal morphology were immunoreactive for γ-aminobutyric acid and substance P, two neurotransmitters of the adult striatum in vivo. Thus, cells of the adult mouse striatum have the capacity to divide and differentiate into neurons and astrocytes.
Transferrin Polymorphism and Population Differences in the Genetic Variability of Chimpanzees
Authors: Goodman Morris , Wisecup William G. , Reynolds Herbert H. , Kratochvil Clyde H.
Published: October 2006

Genetic divergencies between chimpanzee populations, not only between
Pan panicus
and
Pan troglodytes
but also between different groups of the latter, are revealed by typing of transferrin. In particular, differences in the incidence of polymorphic transferrins occur between the groups formed by subdividing a large captive chimpanzee colony of heterogeneous geographic origins into racial types solely on the basis of morphological traits. Genetic variability is extremely high in one of these groups, intermediate in another, and relatively low in a third, with the pattern of changing frequencies of allelic genes at the
T
f
locus following the pattern of geographic distribution of the actual conspecific populations or races for which the groups are named.
Xenon-Iodine Dating: Sharp Isochronism in Chondrites
Authors: Hohenberg C. M. , Podosek F. A. , Reynolds John H.
Published: October 2006

Measurements of the accumulation of Xe
129
from radioactive decay of extinct 1
129
in meteorites show that the I
129
/ I
127
ratio in high-temperature minerals in diverse chondrites was 10
-4
at the time of cooling. The uniformity in the ratio indicates that the minerals cooled simultaneously within 1 or 2 million years.
Molecular Aspects of Lens Cell Differentiation
Authors: Papaconstantinou John
Published: October 2006

I have presented a series of observations on macromolecular interactions which occur during the terminal stages of lens cell differentiation. These are summarized in Fig. 2. Other cell types that undergo similar changes are the erythrocyte and skin cells (epidermis) during the process of keratinization. These other cells are also involved in the synthesis of highly specific proteins, and there are indications that molecular alterations similar to those described for the lens may also occur in these cells (26). Thus, elucidation of a specific series of macromolecular interactions such as those described may provide a basis for the biochemical definition of the terminal stages of cellular differentiation. Differentiation of the reticulocyte, for example, involves inactivation of the nucleus, stabilization of mRNA, and possibly a ribosomal breakdown such as I have described here (26). Furthermore, elucidation of the mechanisms of reactions involving the initiation of tissue-specific protein synthesis and subsequent nuclear inactivation, stabilization of mRNA, and breakdown of the ribosomes may provide a basis for defining the mechanisms of terminal cellular differentiation.

The lens cell has reached its highest form of cellular differentiation when it has formed the fiber cell. With respect to the mechanism of lens fiber cell formation, we would like to know whether specific biochemical changes such as γ-crystallin synthesis are intimately linked to fiber cell formation—that is, whether γ-crystallins are required to bring about the formation of a fiber cell. The potential for synthesizing γ-crystallins is inherent in the genome of the cell. This part of the genome is nonfunctional in the epithelial cell. Can these genes be activated without bringing about a simultaneous cellular elongation, nuclear inactivation and loss of cellular replication, stabilization of mRNA, and breakdown of the ribosomes? The degree of coupling or uncoupling of tissue-specific-protein synthesis to morphogenesis is an important part of the mechanism of cellular differentiation. We feel that we have now reached the stage where we can begin to answer these questions.
Toxicity of Panamanian Poison Frogs (
Dendrobates
): Some Biological and Chemical Aspects
Authors: Daly John W. , Myers Charles W.
Published: October 2006

A small Neotropical frog,
Dendrobates pumilio
, undergoes interpopulational variation in color, degree of toxicity, size, and habits. Differences in body coloration encompass the visible spectrum from red to blue, as well as achromatic black and white. There are wide variations in the degree of toxicity, but these variations are not correlated with supposed warning colors. Extracts of skin yield two toxic compounds characterized as steroidal alkaloids with molecular formulae C
19
H
33
NO
2
and C
19
H
33
NO
3
. The rapid rate of divergent evolution among populations of this frog may result from isolation and chance restriction of original heterozygosity, with subsequent selection acting on different and greatly limited mixtures of alleles.
Water Balance in Desert Arthropods
Authors: Edney E. B.
Published: October 2006

As judged by the number of species, or of individuals, arthropods are an extremely successful group of desert inhabitants. There is very great structural and physiological diversity within the group, and since adaptations to desert life open to one are not open to all. we should not expect to find the maximum possible development of adaptive features in any arthropod simply because it lives in a desert. Most adult insects fly; their larvae and all other arthropods do not, and their adaptations will differ accordingly. Desert beetles have very impermeable cuticles and tolerate high body temperatures, while desert cockroaches live below the sand. have more permeable cuticles, and absorb water vapor. There is probably no single respect in which all desert arthropods differ from insects of other environments. Perhaps a profitable way of viewing desert animals is to recognize that each is a whole organism with a specific collection of adaptations that must be consistent within themselves and which are associated with a specific mode of life and a specific evolutionary history.

The arthropod organization is capable of producing highly efficient desert species. There is, however, a converse way of looking at the situation, which is often neglected but which may be of general biological interest: does the evolution of adaptations to desert environments necessarily involve loss of viability in more mesic habitats? If so, then what are these disadvantages— what, for example, is the disadvantage of a highly impermeable cuticle? In some cases the answer is clear: sandroaches need sand dunes to live in because they are morphologically and behaviorly specialized for this habitat. More often the answer is not obvious.
Sudbury Structure, Ontario: Some Petrographic Evidence for Origin by Meteorite Impact
Authors: French Bevan M.
Published: October 2006

Unusual deformation structures, similar to those observed in rocks from known and suspected meteorite impact craters, are observed in inclusions of basement rock in the Onaping formation at Sudbury, Ontario. These features, which include planar sets in quartz parallel to the (0001) and (101̅3) planes, suggest that the Onaping formation consists of shocked and melted material deposited immediately after a meteorite impact which formed the Sudbury basin.
Isotropy of Cosmic Background Radiation at 4080 Megahertz
Authors: Wilson R. W. , Penzias A. A.
Published: October 2006

We have examined an 18 hour-long record made as part of our program of measurements of the fluxes of a number of discrete radio sources. Since our radiometer employed an absolute reference, it was possible to obtain absolute background data from the reference region observed around each of the 29 sources investigated that day. From the study of a plot mode from this data, we conclude that there is no large-scale deviation from isotropy of more than 0.1°K at 4080 megahertz.
Leaf Epicuticular Waxes
Authors: Eglinton Geoffrey , Hamilton Richard J.
Published: October 2006

The external surface of the higher plants comprises a cuticular layer covered by a waxy deposit. This deposit is believed to play a major part in such phenomena as the water balance of plants and the behavior of agricultural sprays. The wax contains a wide range of organic compounds. These complex mixtures are amenable to modern microchromatographic and microspectrometric analytical procedures. The few surveys which have been made of the species distribution of certain classes of constituents indicate that such distribution may be of limited taxonomic value; however, the wax composition of a species may differ for different parts of the same plant and may vary with season, locale, and the age of the plant.

This fascinating subject, in which the disciplines of botany, biochemistry, chemistry, and physics overlap and interact, is still in a very active state. Much remains to be learned about the composition and fine structure of the wax deposits, and, for this, experimental study of wax crystallization and permeation through artificial membranes will be required. Enzymic studies, radiolabeling, and electron microscopy will be needed to reveal the mode of biogenesis of the wax constituents and their site of formation and subsequent pathway through the cuticle to the leaf surface.
Hu-1: Major Histocompatibility Locus in Man
Authors: Bach Fritz H. , Amos D. Bernard
Published: October 2006

A single locus with 15 or more alleles controls reactivity in mixed leukocyte culture tests. Genes at this locus also control most of the specificities measured by cytotoxic antiserums to leukocytes. Both of these tests can be used to predict survival of skin grafts. It is proposed that this is the major histocompatibility locus in man.
Identification of
ras
Oncogene Mutations in the Stool of Patients with Curable Colorectal Tumors
Authors: Sidransky David , Tokino Takashi , Hamilton Stanley R. , Kinzler Kenneth W. , Levin Bernard , Frost Philip , Vogelstein Bert
Published: October 2006

Colorectal (CR) tumors are usually curable if detected before metastasis. Because genetic alterations are associated with the development of these tumors, mutant genes may be found in the stool of individuals with CR neoplasms. The stools of nine patients whose tumors contained mutations of K-
ras
were analyzed. In eight of the nine cases, the
ras
mutations were detectable in DNA purified from the stool. These patients included those with benign and malignant neoplasms from proximal and distal colonic epithelium. Thus, colorectal tumors can be detected by a noninvasive method based on the molecular pathogenesis of the disease.
Maternal-Effect Selfish Genes in Flour Beetles
Authors: Beeman R. W. , Friesen K. S. , Denell R. E.
Published: October 2006

A previously unknown class of dominant, maternal-effect lethal M factors was found to be widespread in natural populations of the flour beetle, Tribolium castaneum, collected on several continents. Such factors are integrated into the host chromosomes at variable locations and show the remarkable property of self-selection by maternal-effect lethality to all hatchlings that do not inherit a copy of the factor itself. Offspring are rescued by either paternally or maternally inherited copies. The M-bearing chromosome is thereby perpetuated at the expense of its non-M homolog. M factors that map to different regions of the genome do not rescue one another's maternal-effect lethality. Factors expressing these properties are predicted to spread in a population, even in the absence of any additional selective advantage. Similar factors also occur in the related species T. confusum.
A Conformation of Cyclosporin A in Aqueous Environment Revealed by the X-Ray Structure of a Cyclosporin-Fab Complex
Authors: Altschuh Danièle , Vix Olivier , Rees Bernard , Thierry Jean-Claude
Published: October 2006

The conformation of the immunosuppressive drug cyclosporin A (CsA) in a complex with a Fab molecule has been established by crystallographic analysis to 2.65 angstrom resolution. This conformation of CsA is similar to that recently observed in the complex with the rotamase cyclophilin, its binding protein in vivo, and totally different from its conformation in an isolated form as determined from x-ray and nuclear magnetic resonance analysis. Because the surfaces of CsA interacting with cyclophilin or with the Fab are not identical, these results suggest that the conformation of CsA observed in the bound form preexists in aqueous solution and is not produced by interaction with the proteins.
Benzpyrene Hydroxylase Induction by Polycyclic Hydrocarbons in Hamster Embryonic Cells Grown in vitro
Authors: Alfred L. J. , Gelboin H. V.
Published: October 2006

Treatment of hamster embryonic cells with 1,2-benzanthracene for 4 to 48 hours induced a three- to tenfold increase in the activity of benzpyrene hydroxylase. That the increase in enzyme activity was completely prevented by puromycin suggested an induction of enzyme synthesis.
Antibody Variability
Authors: Smithies O.
Published: October 2006

I have analyzed the available amino acid sequence data from 30 myelomatosis-derived proteins. Several types of variation are apparent. I conclude that a major and genetically predetermined contribution to the variability of these proteins and of antibodies could be provided by chromosomal rearrangements resulting from somatic recombination between similar but not identical genes in antibody gene pairs. My hypothesis suggests many new types of experiment and can be tested.
New Reflected-Light Microscope for Viewing Unstained Brain and Ganglion Cells
Authors: Egger M. David , Petráň Mojmír
Published: October 2006

We have designed and constructed a new type of reflected-light microscope to form images including only light reflected near the plane of the object. This selectivity of image formation is based on a mechanical flying-spot technique. Objects difficult or impossible to see with earlier microscopes, such as unstained cells and cell processes in brains of living salamanders and in excised dorsal root ganglia of frogs, have been observed routinely with this microscope.
Crystal Structure of the Solid Electrolyte, RbAg
4
I
5
Authors: Geller S.
Published: October 2006

The crystal structure of the solid electrolyte RbAg
4
I
5
has been determined from single-crystal x-ray diffraction counter data. There are four RbAg
4
I
5
in a cubic unit cell with
a
= 11.24 Å. The structure refinement, by least squares, is based on space group
P
4
1
3 (

O
7

). The arrangement of the iodide ions is similar to that of the manganese atoms in β-manganese, and provides 56 iodide tetrahedra per unit cell, which share faces in such manner as to provide diffusion paths for the silver ions. The occurrence of the two low-temperature phases of RbAg
4
I
5
has been established by x-ray diffraction and optical examination.
Negative Growth and Longevity in the Purple Sea Urchin
Strongylocentrotus purpuratus
(Stimpson)
Authors: Ebert Thomas A.
Published: October 2006

Purple sea urchins were tagged, measured, and placed in a tidepool at Sunset Bay, Oregon. After 1 year, many animals had decreased in size. Accordingly, size is not necessarily a reliable index of age in
Strongylocentrotus purpuratus
; however, it is possible to conclude that these animals are relatively long-lived.
Behavioral Acts Elicited by Stimulation of Single, Identifiable Brain Cells
Authors: Willows A. O. D.
Published: October 2006

By stimulation of and recording from all of the nerve trunks and from over 50 of the large nerve cell bodies in the isolated brain of the nudibranch
Tritonia gilberti
a map of the axonal paths and synaptic connections has been constructed. The nervous correlates of sensory and motor activities can be monitored in single cells of the intact animal. Similarly, discrete responses in local muscles of the body wall and complex behavioral sequences such as turning and swimming are triggered by stimulation of single identifiable units.
Chemical-Cue Preferences of Inexperienced Snakes: Comparative Aspects
Authors: Burghardt Gordon M.
Published: October 2006

Different species of new-born, previously unfed snakes will respond with tongue flicking and prey-attack behavior to water extracts of the skin substances of various small animals. However, there are clear species differences in the type of extract responded to by previously unfed snakes, even within the same genus. These differences correspond to the normal feeding preferences shown by the various species.
Blood Viscosity: Influence of Erythrocyte Deformation
Authors: Chien Shu , Usami Shunichi , Dellenback Robert J. , Gregersen Magnus I.
Published: October 2006

Suspensions of canine and human erythocytes hardened with acetaldehyde differ from the suspensions of normal erythrocytes with respect to their rheological behavior. Normal erythrocytes can be packed by centrifugation so that the sediment volume is nearly 100 percent cells, but the hardened erythrocytes (RBC's) can be packed only to approximately 60 percent cells. At the same cell percentage the viscosity of the hardened RBC suspension is higher than that of the suspension of normal erythocytes. An increase in shear stress deforms the normal erythocytes and lowers the suspension viscosity, but has no influence on the viscosity of the hardened cell suspension. In blood with high cell percentages, the shear deformation of normal RBC's plays an important role in reducing viscosity and facilitating flow at high shear stresses.
Efficiency of Feed Conversion
Authors: Byerly T. C.
Published: October 2006

Under optimum conditions, young healthy individuals of each livestock species may convert about one-third of the digestible protein in its feed into tissue protein in its body. Of this tissue protein, we use about half as food.
Enhanced Protein Synthesis in a Cell-Free System from Hypertrophied Skeletal Muscle
Authors: Hamosh M. , Lesch M. , Baron J. , Kaufman S.
Published: October 2006

Hypertrophy of the rat soleus muscle was induced by tenotomy of the synergistic muscles. Four days after the operation, the weight of the muscle had increased by 30 percent. The hypertrophied muscle had an increased concentration of DNA and RNA, when compared to the contralateral control soleus. Although the amount of myofibrillar protein increased during the 4-day period, the concentration of this component decreased. Microsomes prepared from hypertrophied muscle had an increased RNA concentration. The combined microsomes and
p
H-5 enzyme from hypertrophied muscle supported a faster rate of protein synthesis in vitro than the same system prepared from an equal weight of contralateral muscle which was used as a control.
Modeling Air Pollution in the Washington, D.C., to Boston Megalopolis
Authors: Slade David H.
Published: October 2006

Simplified meteorological models and pollutant source configurations were used to demonstrate the types of pollutant patterns that might be encountered in the Washington, D.C.-Boston megalopolitan corridor. A semirealistic source distribution and source intensity of carbon dioxide were used in this demonstration. The results of the computations suggest that local increases in quantities of pollutants may at times require regional rather than local source consideration.
Serotonin Release from Brain Slices by Electrical Stimulation: Regional Differences and Effect of LSD
Authors: Chase Thomas N. , Breese George R. , Kopin Irwin J.
Published: October 2006

Slices of rat brain which had accumulated tritiated serotonin either in vivo or in vitro were superfused and electrically stimulated. There occurred a marked release of the exogenous amine and, to a lesser extent, its deaminated metabolites, which varied with the region of brain tested and was inhibited by lysergic acid diethylamide.
Delayed Hypersensitivity in Man: A Correlate in vitro and Transfer by an RNA Extract
Authors: Thor Daniel E.
Published: October 2006

The migration of sensitized human monocytic-phagocytic cells from lymph-node tissue-culture suspensions was regularly and specifically inhibited by purified protein derivative or histoplasmin. Moreover, when nonsensitive cells were incubated with an RNA extract from lymph nodes of donors sensitive to purified protein derivative, histoplasmin, or both, the migration of these cells was specifically inhibited by these antigens. Ribonuclease inactivated the RNA extract.
Autonomic Basis for the Rise in Brain Temperature during Paradoxical Sleep
Authors: Baker Mary Ann , Hayward James N.
Published: October 2006

The rise in brain temperature in the rabbit during paradoxical sleep originates in a temperature rise of the cerebral arterial blood. Heat loss from the ear is a major factor in the regulation of arterial blood temperature in the rabbit, and the primary thermal event in paradoxical sleep is a vasoconstriction of the skin of the ear which results in a rise in arterial blood and brain temperatures. These thermal correlates of paradoxical sleep are not present in a cold environment when the ear skin is already maximally vasoconstricted. The persistence of peripheral vasoconstriction during paradoxical sleep in a hot environment suggests a disturbance in autonomic thermoregulatory control.
Autosomal Linkage between the Albumin and Gc Loci in Humans
Authors: Kaarsalo E. , Melartin Liisa , Blumberg B. S.
Published: October 2006

Naskapi and Montagnais families segregating for albumin Naskapi give evidence for close linkage of theGcand albumin loci with a high probability. One possible case of crossover is included in the data.
Decay of Visual Information from a Single Letter
Authors: Posner Michael I. , Keele Steven W.
Published: October 2006

If the trace of a letter can be matched more rapidly with a physically identical letter (as in the pair AA) than it can be with a letter having only the same name (as in the pair Aa), then the trace must preserve the visual aspect of the letter. The visual information from a single letter decays in about 1.5 seconds if the task provides little incentive for preservation.
Hormones and Endocrine Glands of Fishes
Authors: Bern Howard A.
Published: October 2006

The structures discussed above illustrate some of the evolutionary knowledge to be obtained from studies of the comparative biology of the endocrine system among the fishes (see also
17, 78
). The interrenal (adrenocortical) gland is an example of an endocrine structure which shows great morphologic variation in the vertebrate series, and among the fishes themselves. The structural variability implies little selective value for any particular pattern, and, in fact, biochemically the interrenal tissue would seem to be involved in much the same kind of steroidogenesis in the vertebrates generally. However, the hormone aldosterone may be a tetrapod novelty. The caudal neurosecretory system is a good example of a ubiquitous endocrine apparatus, among at least teleostean and elasmo-branch fishes, for which a function has yet to be elucidated and which continues to challenge the comparative physiologist. This system, along with the Stannius corpuscles, is lacking in the tetrapods. The existence of these structures makes it clear that the endocrine biology of fishes cannot be tacitly summarized as being essentially similar to that of the tetrapods, only less well developed. The prolactin situation illustrates the existence of a gland—the pituitary—present among fishes as among tetrapods, which secretes a product only partly related to the tetrapod hormone and having a very different functional significance. In this case it is clear that "the hormone
and
the uses to which it is put" have undergone evolutionary change during vertebrate phylogeny.
Research Comparisons
Authors: Freeman C.
Published: October 2006

In concluding, I will make some personal value judgments explicit. No value judgments need enter into a comparison of inputs, nor need they intrude into comparisons of technological progress and economic growth, except in the choice of these themes for investigation, but value judgments are inevitably involved in the consideration of policy measures which may flow from such comparisons. Insofar as it represents a conscious political decision, the scale of R & D activity and support for science in any particular country reflects a variety of policy goals, only some of which are economic. Moreover, the balance of "home" R & D and "imported" science and technology must also partly reflect political and cultural, as well as more narrowly conceived economic and technological, goals. My personal preference is for a more research-oriented society, both in Britain and in Europe, but for very different policy goals than those pursued in the U.S. and the U.S.S.R. I regard the proposals being canvassed in Britain for drastically cutting back the rate of growth of fundamental and applied research as short-sighted both culturally and economically, and I believe that the real possibilities of acquiring and using American know-how will depend increasingly on strengthening Europe's own R & D capacity. But wherever the balance may lie, all countries benefit to a very considerable extent from scientific and technological exchanges. Autarchy is inefficient, both for the world economy and for world science and technology.
2,5-Dimethoxy-4-methyl-amphetamine (STP): A New Hallucinogenic Drug
Authors: Snyder Solomon H. , Faillace Louis , Hollister Leo
Published: October 2006

We have assessed the effects in normal control volunteers of 2,5-dimethoxy-4-methyl-amphetamine, the chemical present in the hallucinogenic drug STP, in two independent trials. In low doses, this compound produces a mild euphoria. Doses greater than 3 milligrams may cause pronounced hallucinogenic effects lasting about 8 hours and similar to those produced by hallucinogenic doses of lysergic acid diethylamide, mescaline, and psilocybin. 2,5-Dimethoxy-4-methyl-amphetamine, which is chemically related to mescaline and amphetamine, is about 100 times more potent as a hallucinogen than mescaline and only one-thirtieth as potent as lysergic acid diethylamide. Its psychological effects are not accentuated by chlorpromazine.
Goldfish Retina: Organization for Simultaneous Color Contrast
Authors: Daw Nigel W.
Published: October 2006

The majority of ganglion cells in the retina of goldfish have receptive fields organized so that the cells respond particularly to simultaneous contrasts of color. The receptive fields are concentrically arranged. If the cell is excited by red light in the center, then it will also be excited by green light in the periphery, and inhibited by green light in the center or red light in the periphery. The occurrence of this arrangement and the reverse is about equal. The receptive field is much larger than had previously been thought.
Antihemophilic Factor Release by Perfused Liver and Spleen: Relationship to Hemophilia
Authors: Norman John C. , Lambilliotte Jean-Pierre , Kojima Yasushi , Sise Herbert S.
Published: October 2006

As judged by perfusion of isolated organs an antihemophilic factor is produced in the liver and the spleen. Perfusates (from hemophiliacs) that are deficient in the human antihemophilic factor stimulate production of the factor during perfusion. Apparently there is an antihemophilic-factor-stimulating substance in the plasma of hemophiliacs. The data suggest that splenic homotransplantation might alleviate the symptoms of hemophilia.
Behavior Development in the Dog: An Interspecific Analysis
Authors: Cairns Robert B. , Werboff Jack
Published: October 2006

Young dogs were maintained in isolation from other dogs and under varying degrees of exposure to an alien species (mature rabbits). Parametric observations indicate that an interspecific social attachment develops during the initial hours of cohabitation. The later social interaction patterns of the dogs were influenced, but not irrevocably fixed, by the early cross-specific rearing experience.
The Chemical Production of Mutations
Authors: Auerbach C.
Published: October 2006

Since the discovery of the first potent mutagens over 20 years ago, progress in mutation research has been rapid. Many new mutagens, belonging to a variety of chemical classes, have been discovered, and for some of them the reaction with DNA in vitro has been established. It seems that the findings of these chemical investigations usually also apply to viruses which are treated outside the cell. This has made chemical mutagens into an important tool for the analysis of the genetic code. When DNA is treated inside the cell, its reactions would not be expected to be always identical with those observed in vitro; in one case they have, indeed, been found to be different.
Segmented Polyurethane: A New Elastomer for Biomedical Applications
Authors: Boretos John W. , Pierce William S.
Published: October 2006

A segmented polyurethane elastomer, originally developed for elastic thread, is now being used for molded prostheses. Performance of this material when used for components of a heart-assist system warrants a thorough investigation of its effectiveness in a variety of biomedical devices.
Lunar Orbiter Photographs: Some Fundamental Observations
Authors: Trask Newell J. , Rowan Lawrence C.
Published: October 2006

High-resolution photographs returned by Orbiters II and III typically show a surface pitted with small, perfectly circular craters as much as 50 meters in diameter, some of which are strongly clustered; these are superposed on larger, generally shallower craters and must be a mixture of primary and secondary impact craters. Rough terrain is less heavily cratered but is crossed by numerous closely spaced troughs and ridges up to 3 meters high. Terraces, which commonly occur at the base of steep slopes, are also crossed by these troughs and ridges and have relatively few craters. Fresh craters—craters whose exterior slopes are covered with material different from that of the intercrater areas—are rare and are surrounded by angular blocks up to 80 meters in diameter, in varying numbers; these craters apparently undergo gradual destruction to shallow gentle depressions. The frequency of craters 100 meters and more in diameter varies widely, even on level terrain; some of the highest concentrations of craters occur on rays.
Responses of Human Somatosensory Cortex to Stimuli below Threshold for Conscious Sensation
Authors: Libet B. , Alberts W. W. , Wright E. W. , Feinstein B.
Published: October 2006

Averaged evoked responses of somatosensory cortex, recorded subdurally, appeared with stimuli (skin, ventral posterolateral nucleus, cortex) which were subthreshold for sensation. Such responses were deficient in late components. Subthreshold stimuli could elicit sensation with suitable repetition. The primary evoked response was not sufficient for sensation. These facts bear on the problems of neurophysiological correlates of conscious and unconscious experience, and of "subliminal perception."
Modality-Specific Retrograde Amnesia of Fear
Authors: Kim Jeansok J. , Fanselow Michael S.
Published: October 2006

Emotional responses such as fear are rapidly acquired through classical conditioning. This report examines the neural substrate underlying memory of acquired fear. Rats were classically conditioned to fear both tone and context through the use of aversive foot shocks. Lesions were made in the hippocampus either 1, 7, 14, or 28 days after training. Contextual fear was abolished in the rats that received lesions 1 day after fear conditioning. However, rats for which the interval between learning and hippocampal lesions was longer retained significant contextual fear memory. In the same animals, lesions did not affect fear response to the tone at any time. These results indicate that fear memory is not a single process and that the hippocampus may have a time-limited role in associative fear memories evoked by polymodal (contextual) but not unimodal (tone) sensory stimuli.
Isolation of
N
,
N
-Diethyl-
m
-toluamide (Deet) from Female Pink Bollworm Moths
Authors: Jones William A. , Jacobson Martin
Published: October 2006

A chemical search for a natural activator of propylure, the sex pheromone of the pink bollworm moth, revealed that the female moths produce
N,N
-diethyl-
m
-toluamide, an outstanding insect repellent synthesized commercially and never before reported from natural sources. The compound occurs in fairly large amount in female adults and in much lesser amount in female pupae, but it is completely absent in female larvae and in all stages of the male insect. Its role in the life of the insect has not yet been definitely determined.
Glaciation in Taylor Valley, Antarctica, Older Than 2.7 Million Years
Authors: Armstrong Richard Lee , Hamilton Warren , Denton George H.
Published: October 2006

Potassium-argon dates for three samples of basaltic scoria from Taylor Valley, on the west side of McMurdo Sound, indicate that the basalt, which antedates and postdates major glaciations, is at least 2.7 million years old.
Milankovitch Hypothesis Supported by Precise Dating of Coral Reefs and Deep-Sea Sediments
Authors: Broecker Wallace S. , Thurber David L. , Goddard John , Ku Teh-lung , Matthews R. K. , Mesolella Kenneth J.
Published: October 2006

Barbados provides a possibly unique opportunity for reconstruction of the times and elevations of late-Pleistocene high stands of the sea. The island appears to be rising from the sea at a uniform rate that is fast enough to separate in elevation coral-reef tracts formed at successive high stands of the sea. Unaltered coral found in the lower terraces enables high-precision Th
230
: U
234
and Pa
231
: U
235
dating. Three distinct high stands of the sea are found about 122,000, 103,000, and 82,000 years ago. New Pa
231
and Th
230
dates from a deep-sea core also indicate that Ericson's W-X cold-to-warm climatic change occurred close to 126,000 years ago. These data show a parallelism over the last 150,000 years between changes in Earth's climate and changes in the summer insolation predicted from cycles in the tilt and precession of Earth's axis.
Lysergic Acid Diethylamide (LSD): No Teratogenicity in Rats
Authors: Warkany Josef , Takacs Eva
Published: October 2006

Lysergic acid diethylamide (LSD) in doses of 1.5 to 300 micrograms was given to 55 pregnant rats during periods of organogenesis and on the 4th or 5th day of pregnancy to 34 rats. Examination of the resultant 887 young for congenital defects showed no greater frequency than in controls. These experiments failed to prove that LSD is teratogenic in rats.
Bristlecone Pine: Science and Esthetics
Authors: Ferguson C. W.
Published: October 2006

A 7100-year tree-ring chronology has been developed for bristlecone pine,
Pinus aristata
Engelm., in the White Mountains of east-central California by the addition of data from long-dead specimens to the 4600-year record from living trees. These dendrochronological studies have major applications to climatic interpretations, radiocarbon analysis, and the dating of past events.

The great age of these trees and the esthetic appeal of both the trees and their environment are drawing increasing numbers of visitors to the bristlecone pine areas. Concern is expressed for the preservation of this ancient wood.
Isotopic Equilibrium between Shells and Their Environment
Authors: Mook W. G. , Vogel J. C.
Published: October 2006

The carbon-isotopic composition of shell carbonate is shown to be in isotopic equilibrium with bicarbonate dissolved in the water. By measurement of both
13
C and
18
O in a series of brackish-water shells a mean growth temperature can be deduced.
Human Stones
Authors: Lonsdale Kathleen
Published: October 2006

X-ray diffraction studies have shown that there are several different kinds of human urinary calculi, with different age, sex, period, and geographical distributions. Juvenile bladder stones are typically urate and oxalate in small boys in certain stone belts. They have disappeared in some areas, particularly in Britain, but are still common in Thailand. India. and Turkey. Their cause is unknown. Adult bladder stones, formerly common in elderly men, were largely of uric acid and were due to a faulty diet. Juvenile kidney stones are rare, except in Turkey where they are similar to juvenile bladder stones. Adult kidney stones are by far the most universally common, especially in technically developed communities. They are found in both sexes (equally at postmortem), and in the United States and in Czechoslovakia the average number of hospital entries for stones, relative to the whole population, is about 1 per 1000 per annum (increasing) although the incidence in different districts varies by 4 to 1 or more. Such stones are mainly calcium oxalates and calcium and MgNH
4
phosphates. The incidence among the administrative class is at least 20 times that among agricultural workers, relative to their numbers. Stones are reported also to be an occupational hazard for air pilots. It is probably that much more exercise and the drinking of more water to prevent kidney dehydration (spirits and coffee are not effective for this purpose) would lower the high rate of incidence. Moderate acidification would prevent phosphate supersaturation of the urine, but is not effective for oxalates.

It seems certain that, once a suitable seed is formed, epitaxy is largely responsible for deposition from urines that would otherwise remain supersaturated until voided. This would explain the curious radial and layered texture of many stones. Laboratory experiments might suggest ways of preventing orientated overgrowth.
Eye Movement Activity during Sleep and Intellectual Function in Mental Retardation
Authors: Feinberg Irwin
Published: October 2006

A positive relation was found between the amount of eye movement during rapid-eye-movement or paradoxical sleep and estimates of intellectual level in a group of retarded adults. This result supports the hypothesis that during sleep the brain carries out processes important for cognitive function.
Lunar and Martian Surfaces: Petrologic Significance of Absorption Bands in the Near-Infrared
Authors: Adams John B.
Published: October 2006

A reflection minimum at 1 micron, reported for Moon and for Mars, indicates olivine or iron- and calcium-bearing clinopyroxene, or both—major constituents of many basaltic rocks. If the 1-micron absorption features are real, both chondritic and acidic rocks are ruled out as primary constituents of the surfaces of the bodies. The reflectance spectrum of Mars matches closely that of an oxidized basalt.
Presence of the Earliest Vertebrate Hard Tissue in Conodonts
Authors: Sansom I. J. , Smith M. P. , Armstrong H. A. , Smith M. M.
Published: October 2006

From histological investigations into the microstructure of conodont elements, a number of tissue types characteristic of the phosphatic skeleton of vertebrates have been identified. These include cellular bone, two forms of hypermineralized enamel homologs, and globular calcified cartilage. The presence of cellular bone in conodont elements provides unequivocal evidence for their vertebrate affinities. Furthermore, the identification of vertebrate hard tissues in the oral elements of conodonts extends the earliest occurrence of vertebrate hard tissues back by around 40 million years, from the Middle Ordovician (475 million years ago) to the Late Cambrian (515 million years ago).
Olivine-Garnet Transformation in a Meteorite
Authors: Mason Brian , Nelen J. , White John S.
Published: October 2006

Garnet has been identified for the first time as a meteorite mineral in the Coorara chondrite from Western Australia. It replaces olivine grains in a 1-millimeter veinlet traversing the body of the meteorite. The associated olivine has abnormally low birefringence, which suggests a highly shocked condition. Microprobe analyses do not distinguish the garnet from the associated olivine, which has the composition (Mg
.75
Fe
.25
)
2
SiO
4
; the garnet may have the composition Mg
3
Fe
2
Si
3
O
12
but be unresolvable from the accompanying olivine, or alternatively is nonstoichiometric. Transformation of olivine to garnet under high pressure could have significant implications for the phase composition of the Earth's mantle.
Recombination of Influenza A Viruses of Human and Animal Origin
Authors: Kilbourne Edwin D.
Published: October 2006

Simultaneous infection of the allantoic sac of the chick embryo with influenza A/equine 1/56 and any of three recombinants derived from human influenza viruses produced stable hybrids with antigens from each parent strain. These hybrids contain the hemagglutinin protein of the equine virus and the neuraminidase of the human strains. The experiments demonstrate genetic homology of human and equine influenza A viruses and suggest the possibility of their recombination in nature.
Subaerial Diagenesis of Carbonate Sediments: Efficiency of the Solution-Reprecipitation Process
Authors: Harris William H. , Matthews R. K.
Published: October 2006

Interaction between percolating groundwaters and aragonitic carbonate sediments within the vadose zone of the coral cap of Barbados, West Indies, results in dissolution of aragonite and concurrent reprecipitation as low-magnesium calcite. Comparison of the ratios of strontium to calcium in groundwater, aragonitic carbonate, and recrystallized calcite indicates that locally the solution-reprecipitation process is operating at an efficiency greater than 90 percent.
Asparagine Synthetase Activity of Mouse Leukemias
Authors: Horowitz Bernard , Madras Bertha K. , Meister Alton , Old Lloyd J. , Boyse Edward A. , Stockert Elisabeth
Published: October 2006

Various transplanted leukemias and normal tissues of the mouse were tested for asparagine synthetase activity. Leukemias susceptible to suppression by asparaginase have little or no synthetase activity. In contrast, leukemias insensitive to asparaginase exhibit substantial and often very high asparagine synthetase activity. Asparaginase-resistant variants of sensitive leukemias also have considerable synthetase activity. Thus the requirement by certain malignant cells of exogenous asparagine, which entails sensitivity to asparaginase, may be ascribed to lack of asparagine synthetase. Development of asparaginase-resistant variants from asparaginase-sensitive lines is consistently associated with acquisition of asparagine synthetase activity.
Virus-Induced Hemolysis in Erythrocytes Deficient in Glucose-6-phosphate Dehydrogenase
Authors: Necheles Thomas F. , Gorshein Dov
Published: October 2006

Red cells from individuals deficient in glucose-6-phosphate dehydrogenase undergo increased autohemolysis when incubated in the presence of influenza-A virus. Normal red cells, but not those from individuals deficient in glucose-6-phosphate dehydrogenase, show increased activity of the hexose monophosphate shunt in the presence of the virus. This increase in shunt activity appears to be related to oxidation of cellular sulfhydryl groups.
DNA Content of Neurons in the Cat Hippocampus
Authors: Herman Chester J. , Lapham Lowell W.
Published: October 2006

The DNA content of individual cell nuclei of cat hippocampus has been measured by means of a scanning cytophotometric technique. The pyramidal cells are tetraploid, whereas the remaining cell types, which include glial cells, interneurons, and the granule cells of the dentate gyrus, are diploid. Nuclei of tetraploid pyramidal cells are significantly larger than those of diploid granule cells.
Intelligence Has Three Facets
Authors: Guilford J. P.
Published: October 2006

In this limited space I have attempted to convey information regarding progress in discovering the nature of human intelligence. By intensive factor-analytic investigation, mostly within the past 20 years, the multifactor picture of intelligence has grown far beyond the expectations of those who have been most concerned. A comprehensive, systematic theoretical model known as the "structure of intellect" has been developed to put rationality into the picture.

The model is a cubical affair, its three dimensions representing ways in which the abilities differ from one another. Represented are: five basic kinds of operation, four substantive kinds of information or "contents," and six formal kinds of information or "products," respectively. Each intellectual ability involves a unique conjunction of one kind of operation, one kind of content, and one kind of product, all abilities being relatively independent in a population, but with common joint involvement in intellectual activity.

This taxonomic model has led to the discovery of many abilities not suspected before. Although the number of abilities is large, the 15 category constructs provide much parsimony. They also provide a systematic basis for viewing mental operations in general, thus suggesting new general psychological theory.

The implications for future intelligence testing and for education are numerous. Assessment of intellectual qualities should go much beyond present standard intelligence tests, which seriously neglect important abilities that contribute to problem-solving and creative performance in general. Educational philosophy, curriculum-building, teaching procedures, and examination methods should all be improved by giving attention to the structure of intellect as the basic frame of reference. There is much basis for expecting that various intellectual abilities can be improved in individuals, and the procedures needed for doing this should be clear.
Cardioaccelerator Release in
Periplaneta americana
(L)
Authors: Kater Stanley B.
Published: October 2006

Focal electrical stimulation of the brain of
Periplaneta americana
evokes the release of a factor with high cardioaccelerator activity. Results of extirpation of components of the retrocerebral complex from an isolated head preparation imply that the corpus cardiacum is the critical component of this system. The cardioaccelerator is a heat-stable proteinaceous compound.