bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium: Preparation and Catalytic Properties of Particles of Uniform Size
Authors: Turkevich John , Kim Gwan
Published: October 2006

A method has been developed for the preparation of uniform palladium particles of diameter from 55 to 450 angstroms. Uniform particles of gold layered on palladium were also synthesized. Hydrothermal treatment of aluminum hydroxide sol was used to prepare rods of alumina with uniform cross section from 100 to 500 angstroms and of varying lengths. The palladium was adsorbed as individual particles on alumina rods, both present in aqueous suspension. Then the suspension was dried to give a catalyst containing metal particles of uniform size dispersed in open pores produced by the intermeshing of the alumina rods. This procedure guaranteed the absence of diffusion control in the rate of reactions observed experimentally. All stages of the preparation were monitored with the electron microscope. The kinetics of the ethylene-hydrogen reaction were examined by means of a pulse technique. The number of active sites determined by carbon monoxide titration of the surface was equal to the number of surface atoms as determined by the calculation of the quantities of compounds involved in the synthesis and electron microscope examination. Furthermore, the activity per site depended on the method of preparation, being four times smaller when sodium formate was used as a reducing agent instead of sodium citrate. This may be due to the fact that the shape of particles makes certain crystallographic planes more favorable. Decrease in the size of particles to 56 angstroms produced no effect on catalytic activity beyond that due to the increase in the number of surface atoms. The activity of commercial 5 percent palladium on alumina diluted 100-fold with alumina gave 80.4 percent conversion with propylene and 82.7 percent conversion with ethylene. Thus there was little difference in the behavior of the two olefins.
Oxidation of a Polymer Surface with Gas-Phase Singlet (
1
Δ
g
) Oxygen
Authors: Kaplan M. L. , Kelleher P. G.
Published: October 2006

Singlet molecular oxygen (
1
Δ
g
) produced by the microwave discharge of ground state oxygen in a flow system was passed over a film of
cis
-polybutadiene. This treatment resulted in the formation, at the surface, of hydroperoxides which were detected by internal reflection infrared spectroscopy.
Brines and Interstitial Brackish Water in Drill Cores from the Deep Gulf of Mexico
Authors: Manheim F. T. , Sayles F. L.
Published: October 2006

Marked increases in interstitial salinity occur in two drill holes located in the Gulf of Mexico at a water depth of more than 3500 meters. The increases probably arose through diffusion of salt from buried evaporites. In one hole, however, brackish water was encountered on penetrating the oil-permeated cap rock of a salt dome. The phenomenon is attributed to production of fresh water during oxidation of petroleum hydrocarbons and decomposition of gypsum to form native sulfur.
Sulfur: Simulated Long-Range Transport in the Atmosphere
Authors: Reiquam Howard
Published: October 2006

One way to examine the question of whether or not air pollutants are transported over distances on a continental scale is by numerical simulation. A simple atmospheric transport and accumulation model, together with mean wind data and an estimated source distribution in Western Europe, were used in this study. The results suggest that Great Britain and Central Europe contribute to the observed concentrations of sulfur in Northern Europe.
Proteolytic Reaction of Mammalian Spermatozoa on Gelatin Membranes
Authors: Gaddum Penelope , Blandau Richard J.
Published: October 2006

The acrosomes of spermatozoa of several mammalian species show proteolytic activity when applied to fixed gelatin membranes. The technique permits continuous observation of the enzymatic reaction of an individual spermatozoon. Release of the enzyme occurs solely in the region of the acrosome, in a manner which is species-specific.
Teotihuacán: Completion of Map of Giant Ancient City in the Valley of Mexico
Authors: Millon René
Published: October 2006

The detailed archeological map of Teotihuacán, near Mexico City, demonstrates what the prehistoric city was like from its densely crowded center to its more sparsely settled peripheries. The city's population lived in crowded one-story apartment compounds, grouped into neighborhoods based at least partly on occupation. At its height the city had a minimum population of 75,000, a probable population of 125,000, and a possible population of more than 200,000. Those involved in craft production and associated activities may have numbered in the tens of thousands. The scope and intensity of urbanization at Teotihuacán is not paralleled in other contemporary New World centers. The growth potential of the obsidian and other industries, the rise of Teotihuacán as a market and trade center, and its attraction as a religious center may have combined in a self-generating process that led to the creation of Teotihuacán's unique urban society.
Cell Interaction in an Immune Response in vitro: Requirement for Theta-Carrying Cells
Authors: Chan Eva Lee , Mishell Robert I. , Mitchell Graham F.
Published: October 2006

Cytotoxic antiserum to theta antigen reduces the capacity of mouse spleen cells to generate direct and indirect plaque-forming cells to sheep erythrocytes in vitro but does not affect plaque-forming cells, their precursors, or hemopoietic stem cells. The response of spleen cells treated with antiserum to theta antigen is restored by thymus cells incubated in vivo with sheep erythrocytes.
Mammalian Ecology and Epidemiology of Zoonoses
Authors: Muul Illar
Published: October 2006

Insufficient use has been made of ecological data concerning potential hosts in studies to determine the life cycles of zoonotic parasites and pathogens. Factors such as the geographical distribution of hosts, the altitudes at which they live, their affinities for specific habitats, their vertical distribution within the habitat, and the periodicity of their activities have bearing on the hosts' predisposition to involvement in disease cycles. Diets and feeding habits may determine the likelihood of acquiring infection. Reproductive characteristics determine whether a species is suitable as a reservoir or as an amplifying host. Behavioral factors, such as selection of a particular kind of nest site, may also predispose the involvement of the host with parasites and pathogens. Behavior patterns may determine the maximum population densities of hosts. Estimates of population sizes, of relative abundances of species, and of the involvement of species in disease cycles may be strongly influenced by the collecting and sampling methods that are used and also by the behavioral response of the mammals toward collecting devices, such as traps.
Soft Parts of Cephalopods and Trilobites: Some Surprising Results of X-ray Examinations of Devonian Slates
Authors: Stuermer Wilhelm
Published: October 2006

X-ray studies of slates from Bundenbach and Wissenbach (Lower and Middle Devonian, West Germany) revealed a surprising amount of pyritized soft parts of cephalopods and trilobites. The tentacles of cephalopods, the appendages, the intestinal tract, and the structure of the interior of facet eyes of trilobites (
Phacops
species and
Asteropyge
species) were found in a well-preserved state.
Retroviral Recombination and Reverse Transcription
Authors: Hu Wei-Shau , Temin Howard M.
Published: October 2006

Recombination occurs at a high rate in retroviral replication, and its observation requires a virion containing two different RNA molecules (heterodimeric particles). Analysis of retroviral recombinants formed after a single round of replication revealed that (i) the nonselected markers changed more frequently than expected from the rate of recombination of selected markers; (ii) the transfer of the initially synthesized minus strand strong stop DNA was either intramolecular or intermolecular; (iii) the transfer of the first synthesized plus strand strong stop DNA was always intramolecular; and (iv) there was a strong correlation between the type of transfer of the minus strand strong stop DNA and the number of template switches observed. These data suggest that retroviral recombination is ordered and occurs during the synthesis of both minus and plus strand DNA.
Enhancement of Mouse Cytomegalovirus Infection During Host-Versus-Graft Reaction
Authors: Wu Brian C. , Dowling John N. , Armstrong John A. , Ho Monto
Published: October 2006

C
3
H/He mice chronically infected with murine cytomegalovirus were given skin allografts from histoincompatible BALB/c donors. A significant increase in cytomegalovirus titers occurred within 3 days after placement of the graft in the spleens and kidneys of the allograft recipients as compared with control animals. No significant changes in virus titers were detected in the salivary gland, lung, liver, or blood of allograft recipients. These results indicate that the host-versus-graft reaction alone can enhance murine cytomegalovirus in a chronically infected host and may help explain the high incidence of cytomegalovirus infection seen after renal and other allograft transplantation in man.
SH2 and SH3 Domains: Elements that Control Interactions of Cytoplasmic Signaling Proteins
Authors: Koch C. Anne , Anderson Deborah , Moran Michael F. , Ellis Christine , Pawson Tony
Published: October 2006

Src homology (SH) regions 2 and 3 are noncatalytic domains that are conserved among a series of cytoplasmic signaling proteins regulated by receptor protein-tyrosine kinases, including phospholipase C-γ, Ras GTPase (guanosine triphosphatase)-activating protein, and Src-like tyrosine kinases. The SH2 domains of these signaling proteins bind tyrosine phosphorylated polypeptides, implicated in normal signaling and cellular transformation. Tyrosine phosphorylation acts as a switch to induce the binding of SH2 domains, thereby mediating the formation of heteromeric protein complexes at or near the plasma membrane. The formation of these complexes is likely to control the activation of signal transduction pathways by tyrosine kinases. The SH3 domain is a distinct motif that, together with SH2, may modulate interactions with the cytoskeleton and membrane. Some signaling and transforming proteins contain SH2 and SH3 domains unattached to any known catalytic element. These noncatalytic proteins may serve as adaptors to link tyrosine kinases to specific target proteins. These observations suggest that SH2 and SH3 domains participate in the control of intracellular responses to growth factor stimulation.
Speech Perception in Infants
Authors: Eimas Peter D. , Siqueland Einar R. , Jusczyk Peter , Vigorito James
Published: October 2006

Discrimination of synthetic speech sounds was studied in 1- and 4-month-old infants. The speech sounds varied along an acoustic dimension previously shown to cue phonemic distinctions among the voiced and voiceless stop consonants in adults. Discriminability was measured by an increase in conditioned response rate to a second speech sound after habituation to the first speech sound. Recovery from habituation was greater for a given acoustic difference when the two stimuli were from different adult phonemic categories than when they were from the same category. The discontinuity in discrimination at the region of the adult phonemic boundary was taken as evidence for categorical perception.
Blowing of Lunar Soil by Apollo 12: Surveyor 3 Evidence
Authors: Jaffe Leonard D.
Published: October 2006

Analysis of discoloration patterns on the camera of the spacecraft Surveyor 3, after the Apollo 12 lunar module landed nearby, indicates that lunar surface particles were eroded and entrained by lunar module exhaust during the landing and were ejected almost horizontally at 70 meters per second or faster. These particles struck the Surveyor camera and whitened its surface.
Nitrogen, Phosphorus, and Eutrophication in the Coastal Marine Environment
Authors: Ryther John H. , Dunstan William M.
Published: October 2006

The distribution of inorganic nitrogen and phosphorus and bioassay experiments both show that nitrogen is the critical limiting factor to algal growth and eutrophication in coastal marine waters. About twice the amount of phosphate as can be used by the algae is normally present. This surplus results from the low nitrogen to phosphorus ratio in terrigenous contributions, including human waste, and from the fact that phosphorus regenerates more quickly than ammonia from decomposing organic matter. Removal of phosphate from detergents is therefore not likely to slow the eutrophication of coastal marine waters, and its replacement with nitrogen-containing nitrilotriacetic acid may worsen the situation.
The Southern Corn Leaf Blight Epidemic
Authors: Tatum L. A.
Published: October 2006

A dramatic shift in the genetics of host-parasite interaction and balance occurred in the U.S. corn crop in the 1970 growing season. Southern corn leaf blight incited by
Helminthosporium maydis
Nisikado & Miyake evolved from a minor disease that causes an average annual loss of less than 1 percent, to one that caused more than the 12 percent average expected from all diseases of corn in the United States. In 1970 the losses to corn leaf blight approaches 710 million bushels. Reserves of corn and other grains ease the impact on the economy and food supplies but there are important domestic and foreign effects of the loss. The epidemic illustrates the vulnerability of our food crops to pests. Sources of genetic resistance to the new race of
Helminthosporium maydis
are available. The seed industry estimates that for 1971 enough resistant and partially resistant seed to plant about one-half of the crop may be available. Adequate supplies are expected in 1972. Sustained research programs are essential in protecting our food supplies from potential losses of catastrophe magnitude.

Several professional groups, including the American Phytopathological Society and the Entomological Society of America, have urged that a program and facilities be established for the study of exotic pests that threaten our agriculture so that controls may be found before the pests are here. Such a program would be desirable but covers only one aspect of the problem. What is really needed is an overall strengthening of research on crop pests.
GPI-Anchored Cell-Surface Molecules Complexed to Protein Tyrosine Kinases
Authors: Štefanová Irena , Hořejši Václav , Ansotegui Ignacio J. , Knapp Water , Stockinger Hannes
Published: October 2006

Binding of ligand or antibody to certain cell-surface proteins that are anchored to the membrane by glycophosphatidylinositol (GPI) can cause activation of leukocytes. However, it is not known how these molecules, which lack intracellular domains, can transduce signals. The GPI-linked human molecules CD59, CD55, CD48, CD24, and CD14 as well as the mouse molecules Thy-1 and Ly-6 were found to associate with protein tyrosine kinases, key regulators of cell activation and signal transduction. A protein tyrosine kinase associated with the GPI-linked proteins CD59, CD55, and CD48 in human T cells, and with Thy-1 in mouse T cells was identified as p56
lck
, a protein tyrosine kinase related to Src. This interaction of GPI-linked molecules with protein tyrosine kinases suggests a potential mechanism of signal transduction in cells.
Paleomagnetic Study of a Reversal of the Earth's Magnetic Field
Authors: Dunn J. R. , Fuller M. , Ito H. , Schmidt V. A.
Published: October 2006

A detailed record of a field reversal has been obtained from the natural remanent magnetization of the Tatoosh intrusion in Mount Rainier National Park, Washington. The reversal took place at 14.7 ± 1 million years and is interpreted to be from reverse to normal. A decrease in the intensity of the field of about an order of magnitude occurs immediately before the reversal, while its orientation remains substantially unchanged. The onset of the reversal is marked by abrupt swinging of the virtual geomagnetic pole along an arc of a great circle. During the reversal the pole traces a path across the Pacific. In the last stage of the process recorded in the sections, the succession of virtual geomagnetic poles is very similar to those generated by secular variation in the recent past. Although the cooling rate of the intrusion is not sufficiently well known to permit a useful calculation of the duration of the reversal process, an estimate based on the length of the supposed secular variation cycles gives 1 to 4 × 10
3
years for the reversal of field direction and approximately 1 × 10
4
years for the time scale of the intensity changes.
Amyloid Fibril Proteins: Proof of Homology with Immunoglobulin Light Chains by Sequence Analyses
Authors: Glenner G. G. , Terry W. , Harada M. , Isersky C. , Page D.
Published: October 2006

The sequences of the 35 and 36 amino-terminal amino acids of two purified amyloid fibril proteins have been determined. Results indicate that these two proteins are derived from homogeneous immunoglobulin light chains of variable region subgroup V
κI
. The relation between amyloidosis and immunoglobulins is thus more firmly established.
Chemical Methylation of Inorganic Mercury with Methylcobalamin, a Vitamin B
12
Analog
Authors: Imura Nobumasa , Sukegawa Eiji , Pan Shoe-Kung , Nagao Kiyoshi , KIM Jong-Yoon , Kwan Takao , Ukita Tyunosin
Published: October 2006

Chemical methylation of mercuric chloride with methylcobalamin has been studied. Methylated mercury was detected by gas chromatography; and analysis of the products of the reaction by thin-layer chromatography revealed that the methylation proceeded at a remarkably high rate when methylcobalamin and inorganic mercury were mixed. Dimethylmercury was an initial product of the reaction.
Structure of the Calcium-Dependent Lectin Domain from a Rat Mannose-Binding Protein Determined by MAD Phasing
Authors: Weis William I. , Kahn Richard , Fourme Roger , Drickamer Kurt , Hendrickson Wayne A.
Published: October 2006

Calcium-dependent (C-type) animal lectins participate in many cell surface recognition events mediated by protein-carbohydrate interactions. The C-type lectin family includes cell adhesion molecules, endocytic receptors, and extracellular matrix proteins. Mammalian mannose-binding proteins are C-type lectins that function in antibody-independent host defense against pathogens. The crystal structure of the carbohydrate-recognition domain of a rat mannose-binding protein, determined as the holmium-substituted complex by multiwavelength anomalous dispersion (MAD) phasing, reveals an unusual fold consisting of two distinct regions, one of which contains extensive nonregular secondary structure stabilized by two holmium ions. The structure explains the conservation of 32 residues in all C-type carbohydrate-recognition domains, suggesting that the fold seen here is common to these domains. The strong anomalous scattering observed at the Ho L
III
edge demonstrates that traditional heavy atom complexes will be generally amenable to the MAD phasing method.
Molecular Architecture and Electrostatic Properties of a Bacterial Porin
Authors: Weiss M. S. , Abele U. , Weckesser J. , Welte W. , Schiltz E. , Schulz G. E.
Published: October 2006

The integral membrane protein porin from
Rhodobacter capsulatus
consists of three tightly associated 16-stranded β barrels that give rise to three distinct diffusion channels for small solutes through the outer membrane. The x-ray structure of this porin has revealed details of its shape, the residue distributions within the pore and at the membrane-facing surface, and the location of calcium sites. The electrostatic potential has been calculated and related to function. Moreover, potential calculations were found to predict the Ca
2+
sites.
Sex and Population Differences in the Incidence of a Plasma Cholinesterase Variant
Authors: Lubin A. Harold , Garry Philip J. , Owen George M.
Published: October 2006

Accumulating knowledge of polymorphic enzyme systems poses intriguing possibilities of anthropologic genetics. Development of an automated procedure for determination of heterozygosity or homozygosity of the atypical plasma cholinesterase allele (E
1
a
) permitted screening of 2317 individuals during a national Preschool Nutrition Survey and several smaller population studies. Frequencies of the allele (E
1
a
) closely parallel those previously reported. Caucasians manifested a heterozygote male preponderance of 1.85: 1.
Thermal Alteration of Silica Minerals: An Archeological Approach
Authors: Purdy Barbara A. , Brooks H. K.
Published: October 2006

Extensive experiments indicate that the application of heat to flint materials may have conferred an advantage to primitive man in the manufacture of chipped-stone implements. When Florida cherts are slowly heated to between 350° and 400°C and maintained at this temperature for sustained periods, a desirable change occurs in the fracture properties. This alteration takes place when the melting point of the impurities within the intercrystalline spaces is reached; thus the microcrystals of quartz are fitted closer together when materials other than quartz serve as fluxes.
Apples in a Spacecraft
Authors: Alfvén Hannes
Published: October 2006

Some consequences of Newtonian mechanics, previously overlooked, result in a new understanding of the behavior of small bodies in the solar system. Collisions between such bodies lead not to a scattering of these bodies over an increasing volume but instead to a contraction resulting in a "jet stream," with application to meteor streams and streams of asteroids. It is possible that comets are formed by bunching in such streams.
Racemization of Amino Acids in Marine Sediments
Authors: Wehmiller John , Hare P. E.
Published: October 2006

Isoleucine, one of several amino acids isolated from a suite of well-dated deep-sea cores, shows a progressive increase in the degree of racemization with the age of the sediment. Amino acids in sediments show an initial rate of racemization almost an order of magnitude faster than the rate observed for free amino acids at a comparable
p
H and temperature. The observed kinetics depend on a variety of diagenetic processes, but it appears that the ratio of alloisoleucine to isoleucine is a reliable indicator of age for samples less than 400,000 years old; for older samples the results are more ambiguous. Isoleucine is racemic in samples older than about 15 × 10
6
years.
Linguistic Experience Alters Phonetic Perception in Infants by 6 Months of Age
Authors: Kuhl Patricia K. , Williams Karen A. , Lacerda Francisco , Stevens Kenneth N. , Lindblom Björn
Published: October 2006

Linguistic experience affects phonetic perception. However, the critical period during which experience affects perception and the mechanism responsible for these effects are unknown. This study of 6-month-old infants from two countries, the United States and Sweden, shows that exposure to a specific language in the first half year of life alters infants' phonetic perception.
Fecal Pellets: Role in Sedimentation of Pelagic Diatoms
Authors: Schrader Hans-Joachim
Published: October 2006

Membrane-enclosed fecal pellets of planktonic herbivores were sampled at several depths in the Baltic Sea (459 meters deep) and off Portugal (4000 meters deep) by means of a Simonsen multinet. Pellets contained mainly empty shells of planktonic diatoms and silicoflagellates. Two kinds of fecal pellets were found, those with the remains of one species (for example,
Thalassiosira baltica
) and those with the remains of several species (for example,
Chaetoceros
,
Achnanthes
, and
Thalassiosira
). Siliceous skeletons were protected from dissolution during settling by a membrane around the pellet.
Mendelian and Uniparental Alterations in Erythromycin Binding by Plastid Ribosomes
Authors: Mets Laurens J. , Bogorad Lawrence
Published: October 2006

Erythromycin binds specifically to the 52S subunit of the chloroplast ribosome of
Chlamydomonas reinhardi
. A number of erythromycin-resistant mutants whose ribosomes have lost their affinity for the antibiotic have been isolated, but the sedimentation properties of their ribosomes are indistinguishable from those of the wild-type strain. These mutants represent at least three genetic loci. Two of them show Mendelian inheritance, and one of them is inherited in a uniparental manner.
Creation of "Amyloid" Fibrils from Bence Jones Proteins in vitro
Authors: Glenner G. G. , Ein D. , Eanes E. D. , Bladen H. A. , Terry W. , Page D. L.
Published: October 2006

"Amyloid" fibrils have been created from some human Bence Jones proteins by proteolytic digestion under physiologic conditions. These fibrils with an antiparallel, β-pleated sheet conformation consist of only a portion of the variable region of the immunoglobulin light polypeptide chain and share the physical properties of amyloid fibrils. The relation between amyloidosis and immunoglobulins is thus more firmly established and a pathogenetic mechanism for amyloid fibril formation is suggested.
A Rotating Solar Magnetic "Dipole" Observed from 1926 to 1968
Authors: Wilox John M. , Gonzalez Walter
Published: October 2006

A recurring pattern with a period of 26⅞ days observed in the polar geomagnetic field during the interval from 1926 to 1941 appears to persist in the interplanetary magnetic field polarity observed with spacecraft during the interval from 1963 to 1968. This observation suggests the existence of a rotating solar magnetic "dipole" with a period of 26⅞ ± 0.003 days.
Evolving Subduction Zones in the Western United States, as Interpreted from Igneous Rocks
Authors: Lipman Peter W. , Prostka Harold J. , Christiansen Robert L.
Published: October 2006

Variations in the ratio of K
2
O to SiO
2
in andesitic rocks suggest early and middle Cenozoic subduction beneath the western United States along two subparallel imbricate zones dipping about 20 degrees eastward. The western zone emerged at the continental margin, but the eastern zone was entirely beneath the continental plate. Mesozoic subduction apparently occurred along a single steeper zone.
Gonadotropin Secretion during Sleep in Normal Adult Men
Authors: Rubin Robert T. , Kales Anthony , Adler Robert , Fagan Timothy , Odell William
Published: October 2006

Release of luteinizing hormone and follicle stimulating hormone during sleep in young adult men occurred in unrelated, random, arrhythmic peaks, with no consistency from night to night in the same subject. Release of luteinizing hormone was modestly but significantly larger (14 percent) during rapid-eye-movement sleep than it was in non-REM sleep, but release of follicle stimulating hormone was not clearly related to stages of sleep.
Atmospheric Ammonia: Absorption by Plant Leaves
Authors: Hutchinson G. L. , Millington R. J. , Peters D. B.
Published: October 2006

By monitoring the disappearance of ammonia from an airstream flowing through a small growth chamber containing a single plant seedling, it was discovered that plant leaves absorb significant quantities of ammonia from the air, even at naturally occurring low atmospheric concentrations. The measured absorption rates of ammonia showed large diurnal fluctuations and varied somewhat among species, but differed little with the nitrogen fertility level of plants within a species.
Rod-Cone Interaction in Human Scotopic Vision
Authors: Frumkes Thomas E. , Sekuler Marian D. , Reiss Eugene H.
Published: October 2006

Thresholds of a test flash were measured at various time intervals from onset of a conditioning flash under parafoveal scotopic conditions; rods or cones were selectively stimulated by utilizing either 420- or 680-nanometer light. Rod-cone interaction was indicated because conditioning flash presentation increased test threshold above control level for heterochromatic as well as for homochromatic stimulus pairs. The time course of these threshold changes indicates that the rod system has a longer latency than the cone system.
Buried Caldera of Mauna Kea Volcano, Hawaii
Authors: Porter Stephen C.
Published: October 2006

An elliptical caldera (2.1 by 2.8 kilometers) at the summit of Mauna Kea volcano is inferred to lie buried beneath hawaiite lava flows and pyroclastic cones at an altitude of approximately 3850 meters. Stratigraphic relationships indicate that hawaiite eruptions began before a pre-Wisconsin period of ice-cap glaciation and that the crest of the mountain attained its present altitude and gross form during a glaciation of probable Early Wisconsin age.
River Delta Morphology: Wave Climate and the Role of the Subaqueous Profile
Authors: Wright L. D. , Coleman J. M.
Published: October 2006

Application of a comprehensive wave climate program to seven major deltas indicates that deltaic configurations and coastal landform combinations depend to a considerable degree on the wave power adjacent to the shore and on the river discharge relative to wave forces. Nearshore wave power is not correlative with deepwater wave power but, owing to frictional attenuation, is a function of the subaqueous slope. The subaqueous slope, in turn, depends partially on the slope and width of the continental shelf but primarily on the rate at which the river can supply sediments to the nearshore zone. River-dominated configurations result only when the river is able to build flat offshore profiles, which reduce nearshore wave power; where the subaqueous slope is steep, waves reach the shore comparatively undiminished and wave-built forms prevail.
"Walking" in the Newborn
Authors: Zelazo Philip R. , Zelazo Nancy Ann , Kolb Sarah
Published: October 2006

Brief daily exercise of the walking and placing reflexes in the newborn leads to a high rate of responding by 8 weeks and to an earlier onset of walking alone. There appears to be a critical period during which the walking response can be transformed intact from a reflexive to an instrumental action.
Thalamocortical Relay Neurons: Antidromic Invasion of Spikes from a Cortical Epileptogenic Focus
Authors: Gutnick Michael J. , Prince David A.
Published: October 2006

Thalamocortical relay neurons whose axons project into a penicillininduced cortical epileptogenic focus generate bursts of action potentials during spontaneous interictal epileptiform discharges. These bursts originate in intracortical axons and propagate antidromically into thalamic neurons. Repetitive spike generation in cortical axons and presynaptic terminals could produce a potent excitatory drive and contribute to the generation of the large depolarization shifts which are seen in cortical elements during focal epileptogenesis.
Lead Isotopes in North American Coals
Authors: Chow Tsaihwa J. , Earl John L.
Published: October 2006

Lead isotopes in North American coals are equally or much more radiogenic than those in the present continental crust (a mean composition for the continental crust is used). It is practicable to distinguish coal and gasoline lead pollutants by examining their isotopic compositions.
Statistical Thermodynamic Model for the Distribution of Crustal Heat Sources
Authors: Turcotte D. L. , Oxburgh E. R.
Published: October 2006

The observed linear correlation of surface heat flux in continental regions with the radioactive heat release in the surface rocks is consistent with an exponential depth dependence of the concentration of the heat sources. We suggest that this depth dependence can be explained as an equilibrium distribution of the heat-producing elements in a gravitational field. The effective mean mass range of the elemental assemblies being differentiated is predicted, and it appears that potassium, uranium, and thorium diffuse upward in ionic complexes with other elements. Similar considerations should apply to the distribution of other elements in the crust and mantle.
Contraction in
Stentor coeruleus
: A Cinematic Analysis
Authors: Newman Eric
Published: October 2006

The convoluted M bands of the protozoan
Stentor coeruleus
straighten before the animal contracts. Mechanical stimulation initiates contraction locally, and then contraction spreads over the animal with a propagation velocity of 5 to 25 centimeters per second. The contractile wave may spread in both anterior and posterior directions. Electrical stimulation initiates contraction in all areas of Stentor simultaneously.
Neuroanatomical Correlates of Morphine Dependence
Authors: Wei Eddie , Loh Horace H. , Way E. Leong
Published: October 2006

Naloxone hydrochloride, an opioid antagonist, was applied to several discrete brain regions of morphine-dependent rats to precipitate abstinence. Severe withdrawal signs were elicited after administration in the thalamus but not in neocortical, hippocampal, hypothalamic, or tegmental areas of the brain.
Mobility Gaps: A Mechanism for Band Gaps in Melanins
Authors: McGinness John E.
Published: October 2006

The semiconductor behavior of melanins is reviewed and compared with quantum mechanical models of conduction in amorphous solids. The available data are consistent with extensions of Mott's basic model for amorphous semiconductors, whereas they are inconsistent with crystalline semiconductor models. An investigation of the specific conduction mechanisms operative in melanins in terms of the amorphous model should reveal important aspects of the band structure.
Limit Cycles in Predator-Prey Communities
Authors: May Robert M.
Published: October 2006

Essentially all models that have been proposed for predator-prey systems are shown to possess either a stable point equilibrium or a stable limit cycle. This stable limit cycle, an explicitly nonlinear feature, is commonly overlooked in conventional analyses of these models. Such a stable limit cycle provides a satisfying explanation for those animal communities in which populations are observed to oscillate in a rather reproducible periodic manner.
The Oceans: Growth and Oxygen Isotope Evolution
Authors: Chase C. G. , Perry Eugene C.
Published: October 2006

A study of the evolution of the oxygen-18/oxygen-16 ratio of the oceans suggests that this ratio is unlikely to have remained constant with time. Our models suggest that early formation of the oceans is more likely than linear growth.
Eyes Have a Role in Photoperiodic Control of Sexual Activity of
Coturnix
Authors: Homma K. , Wilson W. O. , Siopes T. D.
Published: October 2006

In blinded Japanese quail (
Coturnix coturnix japonica
) encephalic photoreception of the stimulus from long photoperiods is sufficient to induce and maintain normal gonadal function in females (egg laying) and in males (enlargement of the cloacal gland). However, the termination of sexual activity by short days is dependent on these birds having experienced long days at the time of blinding.
Flagellar Movement: A Sliding Filament Model
Authors: Brokaw Charles J.
Published: October 2006

A sliding filament mechanism appears to provide the most satisfactory basis for a simple feedback mechanism for the control of bend propagation and bend initiation by flagella, and is supported by strong experimental evidence. A computer simulation of the movements of a flagellar model based on the sliding filament mechanism demonstrates that this mechanism offers a sufficient explanation for the automatic generation of flagellar bending waves. Further computer simulation studies may provide insight into questions such as the applicability of the sliding filament mechanism to the generation of the more complicated asymmetrical bending patterns of cilia, and the control of the bending pattern by interaction between several sliding filament systems within a flagellum.
Adenosine 3′,5′-Monophosphate: Regional Differences in Chick Embryos at the Head Process Stage
Authors: Reporter Minocher , Rosenquist Glenn C.
Published: October 2006

The concentrations of adenosine 3′,5′-monophosphate and adenosine triphosphate and the activity of phosphodiesterase were determined in different regions of chick embryos at the head process stage. Adenosine 3′,5′-monophosphate, adenosine triphosphate, and phosphodiesterase were estimated to be higher in the mesoderm-forming portions of the hypoblast than in portions that form neural structures from Hensen′s node or the epiblast.
Exocytosis in the Adrenal Medulla Demonstrated by Freeze-Etching
Authors: Smith Una , Smith David S. , Winkler Hans , Ryan James W.
Published: October 2006

Replicas of fractured chromaffin cells are indicative of a range of activities thought to characterize exocytosis, including attachment of secretory vesicles to the plasma membrane, fusion, extrusion of contents, and membrane retrieval. Exocytosis sites are abundant on stimulated cells but are infrequent when calcium is omitted from the system.
On Being Sane in Insane Places
Authors: Rosenhan D. L.
Published: October 2006

It is clear that we cannot distinguish the sane from the insane in psychiatric hospitals. The hospital itself imposes a special environment in which the meanings of behavior can easily be misunderstood. The consequences to patients hospitalized in such an environment—the powerlessness, depersonalization, segregation, mortification, and self-labeling—seem undoubtedly countertherapeutic.

I do not, even now, understand this problem well enough to perceive solutions. But two matters seem to have some promise. The first concerns the proliferation of community mental health facilities, of crisis intervention centers, of the human potential movement, and of behavior therapies that, for all of their own problems, tend to avoid psychiatric labels, to focus on specific problems and behaviors, and to retain the individual in a relatively non-pejorative environment. Clearly, to the extent that we refrain from sending the distressed to insane places, our impressions of them are less likely to be distorted. (The risk of distorted perceptions, it seems to me, is always present, since we are much more sensitive to an individual's behaviors and verbalizations than we are to the subtle contextual stimuli that often promote them. At issue here is a matter of magnitude. And, as I have shown, the magnitude of distortion is exceedingly high in the extreme context that is a psychiatric hospital.)

The second matter that might prove promising speaks to the need to increase the sensitivity of mental health workers and researchers to the
Catch 22
position of psychiatric patients. Simply reading materials in this area will be of help to some such workers and researchers. For others, directly experiencing the impact of psychiatric hospitalization will be of enormous use. Clearly, further research into the social psychology of such total institutions will both facilitate treatment and deepen understanding.

I and the other pseudopatients in the psychiatric setting had distinctly negative reactions. We do not pretend to describe the subjective experiences of true patients. Theirs may be different from ours, particularly with the passage of time and the necessary process of adaptation to one's environment. But we can and do speak to the relatively more objective indices of treatment within the hospital. It could be a mistake, and a very unfortunate one, to consider that what happened to us derived from malice or stupidity on the part of the staff. Quite the contrary, our overwhelming impression of them was of people who really cared, who were committed and who were uncommonly intelligent. Where they failed, as they sometimes did painfully, it would be more accurate to attribute those failures to the environment in which they, too, found themselves than to personal callousness. Their perceptions and behavior were controlled by the situation, rather than being motivated by a malicious disposition. In a more benign environment, one that was less attached to global diagnosis, their behaviors and judgments might have been more benign and effective.
Alpha Particles in Solar Cosmic Rays over the Last 80,000 Years
Authors: Lanzerotti L. J. , Reedy R. C. , Arnold J. R.
Published: October 2006

Present-day (1967 to 1969) fluxes of alpha particles from solar cosmic rays, determined from satellite measurements, were used to calculate the production rates of cobalt-57, cobalt-58, and nickel-59 in lunar surface samples. Comparisons with the activities of nickel-59 (half-life, 8 × 10
4
years) measured in lunar samples indicate that the long-term and present-day fluxes of solar alpha particles are comparable within a factor of approximately 4.
1α-Hydroxy Derivative of Vitamin D
3
: A Highly Potent Analog of 1α,25-Dihydroxyvitamin D
3
Authors: Holick M. F. , Semmler E J. , Schnoes H. K. , Deluca H. F.
Published: October 2006

The 1α-hydroxy derivative of vitamin D
3
has been chemically synthesized and tested for its biological activity. This analog has comparable biological activity on a weight basis to 1,25-dihydroxyvitamin D
3
in the stimulation of intestinal calcium transport and bone calcium mobilization in normal and anephric rats. Because the 1α-hydroxy derivative is synthesized from cholesterol, it is easier and less expensive to prepare than 1α,25-dihydroxy derivative, making it attractive as a drug in the treatment of renal osteodystrophy and hypoparathyroidism.
DNA Base Composition of Rickettsiae
Authors: Tyeryar Franklin J. , Weiss Emilio , Millar David B. , Bozeman F. Marilyn , Ormsbee Richard A.
Published: October 2006

There is a small but distinct difference in DNA base composition between the typhus and spotted fever groups of rickettsiae. The molar percentages of guanine plus cytosine for
Rickettsia prowazeki
,
R. typhi
, and
R. canada
are approximately 30, for
R. rickettsi
,
R. conori
, and
R. akari
they are about 32.5. The percentage for trench fever rickettsia,
Rochalimaea quintana
, is 38.6.
Catecholamine Uptake in Cerebral Cortex: Adaptive Change Induced by Fighting
Authors: Hendley Edith D. , Moisset Beatriz , Welch Bruce L.
Published: October 2006

Kinetics of the catecholainine uptake process in brain were altered by fighting. Significant increases in the apparent Michaelis Constant (
K
m
) for the uptake of norepinephrine into cerebral cortical homogenates and significant increases in the inhibition constant (
K
i
) for
d
-amphetamine inhibition of this uptake occurred in group-caged mice living under chronic attack from aggressive cage mates. Also, significant increases in the apparent
K
m
and maximum velocity (
V
max
) for norepinephrine uptake were observed 18 to 20 hours after the last of a series of short intense daily fights between male mice previously made aggressive by long-term individual caging. These results suggest that the natural stress of fighting leads to (i) lowered affinity for reuptake of norepinephrine into nerve endings of the cerebral cortex, (ii) an increase in the number of uptake sites, and (iii) lowered affinity for
d
-amphetamine.
Europium Anomaly in Plagioclase Feldspar: Experimental Results and Semiquantitative Model
Authors: Weill Daniel F. , Drake Michael J.
Published: October 2006

The partition of europium between plagioclase feldspar and magmatic liquid is considered in terms of the distribution coefficients for divalent and trivalent europium. A model equation is derived giving the europium anomaly in plagioclase as a function of temperature and oxygen fugacity. The model explains europium anomalies in plagioclase synthesized under controlled laboratory conditions as well as the variations of the anomaly observed in natural terrestrial and extraterrestrial igneous rocks.
Earthquake Waves and the Geomagnetic Dynamo
Authors: Mullan Dermott J.
Published: October 2006

It is proposed that earthquake waves energize the geomagnetic dynamo. Fluid motions generated by earthquakes may have enough energy to be in equipartition with fields as large as 100 gauss. Seismic waves from meteoritic impacts with energies sufficient to reverse the field occur every 170,000 years.
Sphaeroma terebrans
: A Threat to the Mangroves of Southwestern Florida
Authors: Rehm Andrew , Humm Harold J.
Published: October 2006

Sphaeroma terebrans
, a wood-boring isopod, is destroying the prop roots of red mangroves along the southwestern coast of Florida to such an extent that the Ten Thousand Islands and mangrove fringes of the mainland are steadily shrinking. Mangroves of the Florida Keys apparently are free of this wood borer.
Microearthquakes at St. Augustine Volcano, Alaska, Triggered by Earth Tides
Authors: Mauk F. J. , Kienle J.
Published: October 2006

Microearthquake activity at St. Augustine volcano, located at the mouth of Cook Inlet in the Aleutian Islands, has been monitored since August 1970. Both before and after minor eruptive activity on 7 October 1971, numerous shallow-foci microearthquake swarms were recorded. Plots of the hourly frequency of microearthquakes often show a diurnal peaking of activity. A cross correlation of this activity with the calculated magnitudes of tidal acceleration exhibited two prominent phase relationships. The first, and slightly more predominant, phase condition is a phase delay in the microearthquake activity of approximately 1 hour from the time of maximum tidal acceleration. This is thought to be a direct microearthquake-triggering effect caused by tidal stresses. The second is a phase delay in the microearthquake activity of approximately 5 hours, which correlates well with the time of maximum oceanic tidal loading. Correlation of the individual peaks of swarm activity with defined components of the tides suggests that it may be necessary for tidal stressing to have a preferential orientation in order to be an effective trigger of microearthquakes.
A Component of Primitive Nuclear Composition in Carbonaceous Meteorites
Authors: Clayton Robert N. , Grossman Lawrence , Mayeda Toshiko K.
Published: October 2006

The oxygen of anhydrous, high-temperature minerals in carbonaceous meteorites is strongly depleted in the heavy stable isotopes
17
O and
18
O. The effect is the result of nuclear rather than chemical processes and probably results from the admixture of a component of almost pure
16
O. This component may predate the solar system and may represent interstellar dust with a separate history of nucleosynthesis.
Color Changes, Unusual Melanosomes, and a New Pigment from Leaf Frogs
Authors: Bagnara Joseph T. , Taylor John D. , Prota Giuseppe
Published: October 2006

Melanosomes of phyllomedusid frogs are unusually large and are composed of an amorphous matrix of thick fibers. Their hitherto undescribed dark red pigment is neither phaeomelanin nor eumelanin, but seems to be related to melanins. Melanophores of at least one of these species,
Agalychnis dacnicolor
, exhibit color change in direct response to illumination, and it is suggested that these chromatophores are innervated.
Mesoscale Ocean Eddies in the North Pacific: Westward Propagation
Authors: Bernstein Robert L.
Published: October 2006

A set of subsurface temperature measurements in the trade wind region northeast of Hawaii reveals large perturbations about the mean state, with zonal wavelengths of 480 kilometers. The perturbations are identified as mesoscale baroclinic eddies, and they appear to drift westward at a rate of 4.7 ± 2.0 centimeters per second. The large-scale (> 1000 kilometers) baroclinic flow at a depth of 200 meters is 1.5 ± 0.7 centimeters per second, also toward the west, and comparable in magnitude with the eddy drift velocity; this finding suggests that the eddy drift is strongly influenced by the large-scale flow. Mesoscale eddies have been discovered in the tropical and subtropical Atlantic Ocean. Their existence in the Pacific Ocean is now confirmed.
"Internal Waves" Advancing along Submarine Canyons
Authors: Shepard Francis P. , Marshall Neil F. , McLoughlin Patrick A.
Published: October 2006

Patterns of alternating up- and downcanyon currents have been traced along the axes of submarine canyons off California. The patterns arrive later at stations nearer the heads of coastal canyons. Where a canyon heads between two islands, the patterns advance down the axis. The propagation speeds of these patterns were estimated as 25 to 88 centimeters per second. Internal waves are the probable explanation.