bluuebunny/crossref_metadata_2025 huggingface dataset:
Sex Bias in Graduate Admissions: Data from Berkeley
Authors: Bickel P. J. , Hammel E. A. , O'Connell J. W.
Published: October 2006

Examination of aggregate data on graduate admissions to the University of California, Berkeley, for fall 1973 shows a clear but misleading pattern of bias against female applicants. Examination of the disaggregated data reveals few decision-making units that show statistically significant departures from expected frequencies of female admissions, and about as many units appear to favor women as to favor men. If the data are properly pooled, taking into account the autonomy of departmental decision making, thus correcting for the tendency of women to apply to graduate departments that are more difficult for applicants of either sex to enter, there is a small but statistically significant bias in favor of women. The graduate departments that are easier to enter tend to be those that require more mathematics in the undergraduate preparatory curriculum. The bias in the aggregated data stems not from any pattern of discrimination on the part of admissions committees, which seem quite fair on the whole, but apparently from prior screening at earlier levels of the educational system. Women are shunted by their socialization and education toward fields of graduate study that are generally more crowded, less productive of completed degrees, and less well funded, and that frequently offer poorer professional employment prospects.
Nitrogen Fixation in Marine Shipworms
Authors: Carpenter Edward J. , Culliney John L.
Published: October 2006

Nitrogen fixation is associated with four shipworm species. A bacterium capable of fixing nitrogen under anaerobic conditions and of liquefying cellulose in culture has been isolated from the gut of one species. High fixation rates (up to 1.5 micrograms of nitrogen per milligram dry weight per hour), which resulted in a doubling of cellular nitrogen in as little as 1.4 days, was associated with
Teredora malleolus
from the Sargasso Sea. Three species from coastal waters were assayed, and of these juveniles showed the highest fixation rates. Nitrogen fixation activity appeared to be inversely related to the ability of shipworms to obtain combined-nitrogen compounds in their diet. It could be a significant source of nitrogen for shipworms and perhaps other oceanic organisms that ingest terrestrial plant material.
Dates for the Middle Stone Age of East Africa
Authors: Wendorf Fred , Laury R. L. , Albritton C. C. , Schild Romauld , Haynes C. Vance , Damon Paul E. , Shafiqullah Mohammed , Scarborough Robert
Published: October 2006

Three potassium-argon age determinations on sanidine from crystalrich pantellerite and volcanic ash in the Main Rift Valley of central Ethiopia indicate that the Middle Stone Age of East Africa began prior to 180,000 years ago. This suggests that the technological developments which characterize the Middle Stone Age have a far greater antiquity than previously estimated.
Early Signs of Language in Child and Chimpanzee
Authors: Gardner R. A. , Gardner B. T.
Published: October 2006

In a sequel to Project Washoe, chimpanzees are being taught American Sign Language from birth by humans who are fluent in the language, including persons who are themselves deaf or whose parents were deaf. The first two subjects began to use signs when they were 3 months old, and these early results indicate that the new conditions are significantly superior to the conditions of Project Washoe. More valid comparisons can now be made between the acquisition of language by children and by chimpanzees.
Memory Retrieval from Long and Short Lists
Authors: Burrows David , Okada Ronald
Published: October 2006

Reaction time in Sternberg's memory retrieval task with both short and long lists is a bilinear function of list length, changing slope at the limits of memory span. Separate long-term and short-term retrieval processes are implied. An alternative one-process model expressed by a logarithmic function is also considered.
Defined Dimensional Changes in Enzyme Cofactors: Fluorescent "Stretched-Out" Analogs of Adenine Nucleotides
Authors: Scopes David I. C. , Barrio Jorge R. , Leonard Nelson J.
Published: October 2006

A concept is presented for testing the dimensional restrictions of enzyme-active sites by stretching the substrate or cofactor by known magnitude. These restrictions of enzyme-active sites specific for purine cofactors were tested by the synthesis and evaluation of
lin
-benzoadenosine 5′-triphosphate, 5′-diphosphate, and 3′,5′-monophosphate with respect to enzyme binding and activity. These "stretched-out" (by 2.4 angstroms) versions of the adenine ribonucleotides bind strongly, slow the enzymatic rates, and have useful fluorescence properties.
Gas Chromatographic Column for the Viking 1975 Molecular Analysis Experiment
Authors: Novotny M. , Hayes J. M. , Bruner F. , Simmonds P. G.
Published: October 2006

A gas chromatographic column has been developed for use in the remote analysis of the martian surface. The column, which utilizes a liquid-modified organic adsorbent (Tenax) as the stationary phase, provides efficient transmission and resolution of nanogram quantities of organic materials in the presence of millionfold excesses of water and carbon dioxide.
Plant "Primary Perception": Electrophysiological Unresponsiveness to Brine Shrimp Killing
Authors: Horowitz Kenneth A. , Lewis Donald C. , Gasteiger Eegar L.
Published: October 2006

A test of the "primary perception" hypothesis proposed by Backster in 1968 was made by recording electrical activity from the leaves of
Philodendra scandentia
while randomly ejecting the contents of micropipettes filled with brine shrimp or distilled water into boiling water. Test conditions conformed to those published by Backster or communicated in personal exchanges. Data were analysed from five experiments, in each of which recordings were made from four plants in the presence of three brine shrimp killings and two control water ejections. Inspection of the data and analysis by two statistical methods revealed no relationship between brine shrimp killing and electrical "responsiveness" of philodendron.
Photosynthate and Nitrogen Requirements for Seed Production by Various Crops
Authors: Sinclair T. R. , de Wit C. T.
Published: October 2006

Seed biochemical composition was the basis for segregating 24 crops into four distinct groups. Nitrogen requirements of pulses and soybeans were so great that sustained seed growth demanded continued nitrogen translocation from vegetative tissues. This translocation must eventually induce senescence in these tissues, restrict the duration of the seed-fill period, and limit seed yield.
Requirement of Microfilaments in Sorting of Actin Messenger RNA
Authors: Sundell Cynthia L. , Singer Robert H.
Published: October 2006

Specific messenger RNAs (mRNAs) can be sequestered within distinct cellular locations, but little is known about how this is accomplished. The participation of the three major cellular filaments in the localization of actin mRNA was studied in chicken embryo fibroblasts. Movement of actin mRNA to the cell periphery and maintenance of that regionalization required intact microfilaments (composed of actin) but not microtubules or intermediate filaments. The results presented here suggest that actin-binding proteins may participate in mRNA sorting.
Photoproduction of Molecular Hydrogen by a Plant-Algal Symbiotic System
Authors: Newton J. W.
Published: October 2006

The rapidly growing water fern
Azolla
, which contains a nitrogen-fixing blue-green algal symbiont, has been studied as a possible system for photoproduction of molecular hydrogen. When this plant is grown on a combined nitrogen supply, photochemically generated hydrogen can be diverted through the algal nitrogenase system, which serves as a source of molecular hydrogen generated from water. This symbiosis has several advantages as a possible biological energy conversion system.
Surface Oxidation: A Major Sink for Water on Mars
Authors: Huguenin Robert L.
Published: October 2006

Surface oxidation irreversibly removes both oxygen and hydrogen from the martian atmosphere at a rate of 10
8
to 10
11
per square centimeter per second. This rate corresponds to a net loss of 10
25
to 10
28
per square centimeter (10
2
to 10
5
grams per square centimeter) of H
2
O, if it is assumed that the loss rate is uniform over geologic time. Heretofore, exospheric escape was considered to be the principal irreversible sink for H
2
O, but the loss rate was estimated to be only 10
8
per square centimeter per second. It is possible that surface oxidation may have had a minor effect on the supply of H
2
O in the regolith and polar caps.
Retardation of Autoshaping: Control by Contextual Stimuli
Authors: Tomie Arthur
Published: October 2006

Training pigeons with random presentations of a tone and food proactively interferes with the acquisition of autoshaped keypecking to a lighted key. The interference effect is context-specific (observed only when testing for autoshaping occurs in the initial training environment). An interpretation based on blocking by background cues is suggested by the data.
N
-Nitroso Compounds: Detection in Ambient Air
Authors: Fine D. H. , Rounbehler D. P. , Belcher N. M. , Epstein S. S.
Published: October 2006

By use of a new, highly selective detection technique for
N
-nitroso compounds, which is sensitive to picogram quantities and which is based on the catalytic cleavage of the N-NO bond and the subsequent detection of the nitrosyl radical, dimethylnitrosamine has been found in concentrations of 0.02 to 0.96 part per billion in three out of five air samples from Baltimore, Maryland, and 0.014 to 0.051 part per billion in five out of six air samples from Belle, West Virginia. The sensitivity of the analytical procedures used was 1 part in 10
12
. The presence of dimethylnitrosamine has been confirmed by using the new detector in conjunction with both a gas-liquid chromatograph and a high-performance liquid chromatograph. In addition, between one and three as yet unidentified
N
-nitroso compounds were detected in both cities.
N
-Nitroso compounds were not found in air samples from Philadelphia, Pennsylvania; Wilmington, Delaware; and Waltham, Massachusetts.
A Neuron-Silicon Junction: A Retzius Cell of the Leech on an Insulated-Gate Field-Effect Transistor
Authors: Fromherz Peter , Offenhäusser Andreas , Vetter Thomas , Weis Jürgen
Published: October 2006

An identified neuron of the leech, a Retzius cell, has been attached to the open gate of a
p
-channel field-effect transistor. Action potentials, spontaneous or stimulated, modulate directly the source-drain current in silicon. The electronic signals match the shape of the action potential. The average voltage on the gate was up to 25 percent of the intracellular voltage change. Occasionally weak signals that resemble the first derivative of the action potential were observed. The junctions can be described by a model that includes capacitive coupling of the plasma membrane and the gate oxide and that accounts for variable resistance of the seal.
Gibbons and Their Territorial Songs
Authors: Marshall Joe T. , Marshall Elsie R.
Published: October 2006

Discovery of the great call of the Javan gibbon and finding an enclave of the agile gibbon in Kalimantan permit for the first time a comparison of vocalizations among all major taxa of
Hylobates
The songs are stereotyped, constant throughout the interrupted areas of distribution of each taxon, and are sexually divocal.
Conodont Pearls?
Authors: Glenister Brian F. , Klapper Gilbert , Chauff Karl M.
Published: October 2006

Conodonts are zoologically enigmatic, toothlike phosphatic microfossils occurring in marine sedimentary rocks ranging in age from Cambrian to Triassic. Dimpled spheres of less than 1 millimeter in diameter are sporadic associates of conodonts and have identical chemical composition and microstructure. Mineralogy, morphology, and occurrence of these spheres suggest that they are pearls secreted by the conodont-bearing animal
Sanidine: Predicted and Observed Monoclinic-to-Triclinic Reversible Transformations at High Pressure
Authors: Hazen Robert M.
Published: October 2006

High sanidine, (K,Na)AlSi
3
O
8
, transforms reversibly to a triclinic phase at high pressure. This is analogous to the high-temperature monalbite transformation. Disordered alkali feldspars of various compositions have unit-cell dimensions which are very similar at the transition (
a
= 8.30 Å,
b
= 12.97 Å,
c
= 7.14 Å, and β = 116.2°), indicating that the transformation is structurally controlled. Changes in temperature, pressure, and the sodium/potassium ratio cause similar structural variations: angles between adjacent, rigid tetrahedra vary to accommodate changing effective alkali cation sizes.
Viking Orbital Colorimetric Images of Mars: Preliminary Results
Authors: Soderblom Laurence A.
Published: October 2006

Color reconstruction and ratios of orbital images of Mars confirm Earth-based measurements showing red/violet ratios for bright areas to be roughly 1.5 times greater than dark areas. The new results show complex variation among dark materials; dark streaks emanating from craters in southern cratered terrains are much bluer than dark materials of the north equatorial plains on which Viking 1 landed.
U.S. Universities and the World Food Problem
Authors: Whitaker Morris D. , Wennergren E. Boyd
Published: October 2006

The imponderable now is time. Certainly, it is in short supply if we hope to improve the world's prospects for food production. The requisite scientific skills that can contribute to greater world agricultural production exist in a uniquely concentrated form in the U.S. universities. Incentives for increased university involvement in technical assistance created by the International Development and Food Assistance Act of 1975 will not become effective until a mechanism which guarantees adequate and long-term funding is established. A continuing dialogue to define the nature and scope of needed reforms is necessary if maximum involvement of U.S. scientists in agricultural technical assistance is to be realized. Such involvement is vital in meeting the food needs of the developing world.
DNA Deaminating Ability and Genotoxicity of Nitric Oxide and its Progenitors
Authors: Wink David A. , Kasprzak Kazimierz S. , Maragos Chris M. , Elespuru Rosalie K. , Misra Manoj , Dunams Tambra M. , Cebula Thomas A. , Koch Walter H. , Andrews A. W. , Allen Jane S. , Keefer Larry K.
Published: October 2006

Nitric oxide (NO), a multifaceted bioregulatory agent and an environmental pollutant, can also cause genomic alterations. In vitro, NO deaminated deoxynucleosides, deoxynucleotides, and intact DNA at physiological pH. That similar DNA damage can also occur in vivo was tested by treating
Salmonella typhimurium
strain TA1535 with three NO-releasing compounds, including nitroglycerin. All proved mutagenic. Observed DNA sequence changes were >99% C→T transitions in the
his
G46 (CCC) target codon, consistent with a cytosine-deamination mechanism. Because exposure to endogenously and exogenously produced NO is extensive, this mechanism may contribute to the incidence of deamination-related genetic disease and cancer.
Dibutyryl Cyclic AMP Mimics Ovariectomy: Nuclear Protein Phosphorylation in Mammary Tumor Regression
Authors: Cho-Chung Yoon Sang , Redler Bruce H.
Published: October 2006

Growth of mammary carcinoma induced by 7,12-dimethylbenz(
a
)anthracene is arrested by either ovariectomy or treatment with N
6
,O
2
′-dibutyryl cyclic adenosine 3′,5′-monophosphate (dibutyryl cyclic AMP). When this occurs, a new nonhistone protein species becomes the predominant endogenous substrate of cyclic AMP-dependent protein kinase in the tumor nuclei. Phosphorylation of this regression-associated protein ceases when resumption of tumor growth is induced by either the injection of 17β-estradiol or cessation of dibutyryl cyclic AMP treatment. Thus phosphorylation of regression-associated protein may play a role in the regression of hormone-dependent mammary tumors.
Toward the Primary Prevention of Cancer
Authors: Henderson Brian E. , Ross Ronald K. , Pike Malcolm C.
Published: October 2006

This is the threshold of an era when many of the most prevalent human cancers can, to a significant extent, be prevented through life-style changes or medical interventions. For lung cancer, the leading cause of cancer deaths in the United States, the major cause, cigarette smoking, is known and strategies for reducing smoking are slowly succeeding. Dietary changes can reduce the risk of developing large bowel cancer, the second most common cancer overall. The etiology of the major cancer in women, cancer of the breast, is sufficiently well understood that large-scale medical intervention trials are imminent. Recent changes in the incidence and mortality of these and the other major human cancers are reviewed with a brief explanation as to why these changes have occurred, followed by a summary of the state of knowledge regarding the major causes of cancer.
Overlapping Platelets: A Diffusion Barrier in a Teleost Swimbladder
Authors: Brown D. Scott , Copeland D. Eugene
Published: October 2006

Overlapping platelets are layered within the connective tissue of the wall of a closed (physoclistous) swimbladder. The close, staggered arrangement of the platelets is viewed as a physical barrier that can interfere with the diffusion pathway of gas molecules. The result is a more efficient retention of gas pressures within the swimbladder.
Volcanic Activity and Great Earthquakes at Convergent Plate Margins
Authors: Carr Michael J.
Published: October 2006

Volcanoes are unusually quiet for periods of a few years to a few decades prior to great shallow-thrust earthquakes. This is the most obvious part of an apparent pattern of volcanic activity related to the occurrence of great earthquakes at some convergent plate margins.
Triassic-Jurassic Tetrapod Extinctions: Are They Real?
Authors: Olsen Paul E. , Galton Peter M.
Published: October 2006

Terrestrial vertebrate fossils show that part of the Newark supergroup of the eastern United States, all of the Glen Canyon group of the southwestern United States, and the Upper Stormberg group of southern Africa are Early Jurassic. This new correlation demonstrates that the supposed widespread tetrapod extinction at the Triassic-Jurassic boundary is an artifact of spurious correlation.
Lectin Release by Soybean Seeds
Authors: Fountain David W. , Foard Donald E. , Replogle Wendy D. , Yang Wen K.
Published: October 2006

Lectin is released from soybean seeds during water uptake. Hemagglutination activity data show that the lectin is a preferential release product within the first 8 hours of hydration. A qualitative filter-paper assay for detection of lectin released by single seeds is used to show that the release phenomenon is independent of seed viability and insensitive to azide.
Paleoenvironment and Human Settlement in Japan and Korea
Authors: Pearson Richard
Published: October 2006

The climate of Japan changed from cooler than present (12,000 to 11,000 years ago) to warmer than present (8000 to 4000 years ago) to cooler than present (4000 to 1500 years ago). The height of the warm period coincides with the Jomon marine transgression, which flooded coastal lands and invaded river valleys. The Jomon culture of the post-Pleistocene shows changes in subsistence patterns and site location at different time periods. Although it is very long and there is definite cultural continuity, shifts in settlement patterns and the development of fishing and collecting techniques show that it was not static. Village layouts and intersite relationships are examined. While there is not yet enough information for the reconstruction of the environment of the Korean peninsula, investigations seem to show shifts in settlement location from low coastal areas to hills and slopes occurring at relatively the same time periods as in Japan. House plans and average size of dwellings in Korea are briefly discussed.
Hydroxyl Radical Reactivity with Diethylhydroxylamine
Authors: Gorse R. A. , Lii R. R. , Saunders B. B.
Published: October 2006

Diethylhydroxylamine (DEHA) reacts with gas-phase hydroxyl radicals on every third collision, whereas the corresponding reaction in aqueous solution is considerably slower. The high gas-phase reactivity explains the predicted inhibitory effect of DEHA in atmospheric smog processes. Results from the studies in the aqueous phase are helpful in predicting the mechanism of the reaction of DEHA with hydroxyl radicals.
Specification of Jaw Muscle Identity in Zebrafish: Correlation with
engrailed
-Homeoprotein Expression
Authors: Hatta Kohei , Schilling Thomas F. , BreMiller Ruth A. , Kimmel Charles B.
Published: October 2006

Molecules that determine the specific features of individual muscles in vertebrates are unknown. Antibody labeling studies described here revealed a molecular difference among muscles in the zebrafish head, in that two functionally related jaw muscles (the levator arcus palatini and the dilator operculi), and not other head muscles, expressed
engrailed
-homeodomain proteins. Expression began in mesoderm-derived muscle-precursor cells in the paraxial mesenchyme and continued during muscle morphogenesis and differentiation. Growth cones of trigeminal motoneurons that innervate these muscles associated with the precursors within a few hours of the time they began to express
engrailed
. It is proposed that the
engrailed
proteins in these cells establish muscle identity and neuromuscular target recognition.
Wolf-Pack Buffer Zones as Prey Reservoirs
Authors: Mech L. David
Published: October 2006

In a declining herd, surviving deer inhabited overlapping edges of wolf-pack territories. There, wolves hunted little until desperate, in order to avoid fatal encounters with neighbors. Such encounters reduce wolf numbers and predation pressure and apparently allow surviving deer along territory edges to repopulate the area through dispersal of their prime, less vulnerable offspring into territory cores.
The Charnockite Geotherm
Authors: Saxena S. K.
Published: October 2006

Charnockite, a hypersthene-bearing granite, and other associated rocks of the charnockite series have a global distribution. These rocks, according to evidence from mineral-chemical and experimental phase equilibrium relations, formed or recrystallized at temperatures between 800° and 900°C and at relatively shallow depths of 6 to 12 kilometers. This evidence indicates the existence of geothermal gradients of 70° to 100°C per kilometer probably at various times, the latest being around 1300 × 10
6
years ago.
Airborne Short-Lived Radionuclides of Unknown Origin in Sweden in 1976
Authors: De Geer Lars-Erik
Published: October 2006

On five occasions during the first half of 1976 traces of neptunium-239 and molybdenum-99 were detected in southern Sweden. These activities were accompanied by small amounts of fission products such as iodine-131 and barium-140. One of the events was coincident in time with large peaks in the atmospheric tritium gas concentration.
Primordial Noble Gases in Chondrites: The Abundance Pattern Was Established in the Solar Nebula
Authors: Alaerts Leo , Lewis Roy S. , Anders Edward
Published: October 2006

Ordinary chondrites, like carbonaceous chondrites, contain primordial noble gases mainly in a minor phase comprising ≤0.05 percent of the meteorite, probably an iron-chromium sulfide. The neon-20/argon-36 ratios decrease with increasing argon-36 concentration, as expected if the gas pattern was established by condensation from the solar nebula, and was negligibly altered by metamorphism in the meteorite parent bodies. Meteoritic and planetary matter apparently condensed over a substantial range of temperatures.
Coordinate Regulation of β-Lactamase Induction and Peptidoglycan Composition by the Amp Operon
Authors: Tuomanen E. , Lindquist S. , Sande S. , Galleni M. , Light K. , Gage D. , Normark S.
Published: October 2006

The
amp
operon, which is located on the
Escherichia coli
chromosome, modulates the induction of plasmid-borne β-lactamase genes by extracellular β-lactam antibiotics. This suggests that the gene products AmpD and AmpE may function in the transduction of external signals. β-Lactam antibiotics are analogs of cell wall components that can be released during cell wall morphogenesis of enterobacteria. The
amp
operon was studied to determine its importance in signal transduction during cell wall morphogenesis. The peptidoglycan compositions of
amp
mutants were determined by high-performance liquid chromatography and fast atom bombardment mass spectrometry. When a chromosomal or plasmid-borne copy of
ampD
was present, the amount of pentapeptide-containing muropeptides in the cell wall increased upon addition of the cell wall constituent diaminopimelic acid to the growth medium. These results suggest that β-lactamase induction and modulation of the composition of the cell wall share elements of a regulatory circuit that involves AmpD.
Escherichia coli
requires AmpD to respond to extracellular signaling amino acids, such as diaminopimelic acid, and this signal transduction system may regulate peptidoglycan composition in response to cell wall turnover products.
A Kinetic Partitioning Model of Selective Binding of Nonnative Proteins by the Bacterial Chaperone SecB
Authors: Hardy Simon J. S. , Randall Linda L.
Published: October 2006

An in vitro assay for the interaction of SecB, a molecular chaperone from
Escherichia coli
, with polypeptide ligands was established based on the ability of SecB to block the refolding of denatured maltose-binding protein. Competition experiments show that SecB binds selectively to nonnative proteins with high affinity and without specificity for a particular sequence of amino acids. It is proposed that selectivity in binding is due to a kinetic partitioning of polypeptides between folding and association with SecB.
The CANDU Reactor System: An Appropriate Technology
Authors: Robertson J. A. L.
Published: October 2006

CANDU power reactors are characterized by the combination of heavy water as moderator and pressure tubes to contain the fuel and coolant. Their excellent neutron economy provides the simplicity and low costs of once-through natural-uranium fueling. Future benefits include the prospect of a near-breeder thorium fuel cycle to provide security of fuel supply without the need to develop a new reactor such as the fast breeder. These and other features make the CANDU system an appropriate technology for countries, like Canada, of intermediate economic and industrial capacity.
Temperature Coupling in the Vocal Communication System of the Gray Tree Frog,
Hyla versicolor
Authors: Gerhardt H. Carl
Published: October 2006

The gray tree frog mates over a temperature range of at least 9°C. Gravid females, tested at two different temperatures, preferred synthetic mating calls with temperature-dependent temporal properties similar to those produced by a male at about the same temperature as their own. Thus, the vocalization system and the temporal pattern recognition system are affected by temperature in a qualitatively similar fashion.
Morphogenetic Responses of Cultured Totipotent Cells of Carrot (
Daucus carota
var.
carota
) at Zero Gravity
Authors: Krikorian Abraham D. , Steward F. C.
Published: October 2006

An experiment designed to test whether embryos capable of developing from isolated somatic carrot cells could do so under conditions of weightlessness in space was performed aboard the unmanned Soviet biosatellite Kosmos 782 under the auspices of the joint United States-Soviet Biological Satellite Mission. Space flight and weightlessness seem to have had no adverse effects on the induction of embryoids or on the development of their organs. A portion of the crop of carrot plantlets originated in space and grown to maturity were not morphologically different from controls.
Temporary Queens in
Metapolybia
Wasps: Nonreproductive Helpers Without Altruism?
Authors: West-Eberhard Mary Jane
Published: October 2006

In
Metapolybia aztecoides
some mated females produce only workers, losing in competition with other similar egg-layers before producing either males or queens. Worker production by these ultimately nonreproductive females may incidentally benefit others without lowering individual fitness (without "altruism"). It could be a by-product of mutualism rather than of kin selection or parental manipulation.
Aztec Cannibalism: An Ecological Necessity?
Authors: Ortiz de Montellano Bernard R.
Published: October 2006

It has been proposed that Aztec human sacrifice and cannibalism can best be explained as a response to population pressure and famine. The greatest amount of cannibalism, however, coincided with times of harvest, not with periods of scarcity, and is better explained as a thanksgiving. Tenochtitlan received large quantities of food tribute and engaged in intensive (
chinampa
) agriculture. These two sources alone would have provided enough to feed practically the entire population of the city. The Aztecs also consumed various animals and insects that were good protein sources. The amount of protein available from human sacrifice would not have made a significant contribution to the diet. Cannibalism was not motivated by starvation but by a belief that this was a way to commune with the gods.
Hydrogen Cyanide Production During Reduction of Nitric Oxide over Platinum Catalysts: Transient Effects
Authors: Voorhoeve R. J. H. , Patel C. K. N. , Trimble L. E. , Kerl R. J.
Published: October 2006

The formation of hydrogen cyanide during the catalytic reduction of nitric oxide (NO) with carbon monoxide and hydrogen was studied with a bench-scale flow reactor. The previously reported inhibition by sulfur dioxide of the formation of hydrogen cyanide was found to be counteracted by transient admission of oxygen to the catalyst. These results are discussed in the context of the control of automotive emissions of NO and the prevention of hydrogen cyanide production during such control.
Winter Rain and Summer Ozone: A Predictive Relationship
Authors: Sandberg J. S. , Basso M. J. , Okin B. A.
Published: October 2006

Insights from dendrochronology have provided a new seasonal predictor for air pollution meteorology. In the San Francisco Bay Area summer ozone excesses over the federal ozone standard are correlated (correlation coefficient
r =
.87) with precipitation for the two preceding winters, a factor related to tree-ring width in a precipitation-stressed climate. The hypothesis that reactive hydrocarbon emissions from vegetative biomass affects these ozone excesses was supported by a similar correlation between summer hydrocarbon average maximums and the two-winter precipitation factor, reaching
r =
.88 at suburban stations. A weak tendency for hot summers to follow wet winters (in 16 years of California data) explains only a minor part of the ozone-rain relationship in multiple correlations.
Search Image for Leaf Shape in a Butterfly
Authors: Rausher Mark D.
Published: October 2006

The butterfly
Battus philenor
forms search images for leaf shape when searching for its two larval host plants in southeast Texas. This behavior increases the rate of discovery of host plants and permits females to track changes in relative host plant suitability for larval growth. Apostatic selection resulting from search image formation is a likely explanation for divergence in leaf shape by the two host plants.
Max: A Helix-Loop-Helix Zipper Protein That Forms a Sequence-Specific DNA-Binding Complex with Myc
Authors: Blackwood Elizabeth M. , Eisenman Robert N.
Published: October 2006

The myc protooncogene family has been implicated in cell proliferation, differentiation, and neoplasia, but its mechanism of function at the molecular level is unknown. The carboxyl terminus of Myc family proteins contains a basic region helix-loop-helix leucine zipper motif (bHLH-Zip), which has DNA-binding activity and has been predicted to mediate protein-protein interactions. The bHLH-Zip region of c-Myc was used to screen a complementary DNA (cDNA) expression library, and a bHLH-Zip protein, termed Max, was identified. Max specifically associated with c-Myc, N-Myc, and L-Myc proteins, but not with a number of other bHLH, bZip, or bHLH-Zip proteins. The interaction between Max and c-Myc was dependent on the integrity of the c-Myc HLH-Zip domain, but not on the basic region or other sequences outside the domain. Furthermore, the Myc-Max complex bound to DNA in a sequence-specific manner under conditions where neither Max nor Myc exhibited appreciable binding. The DNA-binding activity of the complex was dependent on both the dimerization domain and the basic region of c-Myc. These results suggest that Myc family proteins undergo a restricted set of interactions in the cell and may belong to the more general class of eukaryotic DNA-binding transcription factors.
Control of Larval Development by Chemosensory Neurons in
Caenorhabditis elegans
Authors: Bargmann Cornelia I. , Horvitz H. Robert
Published: October 2006

Larval development of the nematode
Caenorhabditis elegans
is controlled by the activities of four classes of chemosensory neurons. The choice between normal development and development into a specialized larval form called a dauer larva is regulated by competing environmental stimuli: food and a dauer pheromone. When the neuron classes ADF, ASG, ASI, and ASJ are killed, animals develop as dauer larvae regardless of environmental conditions. These neurons might sense food or dauer pheromone, or both, to initiate the specialized differentiation of many cell types that occurs during dauer formation. Entry into and exit from the dauer stage are primarily controlled by different chemosensory neurons. The analysis of mutants defective in dauer formation indicates that the chemosensory neurons are active in the absence of sensory inputs and that dauer pheromone inhibits the ability of these neurons to generate a signal necessary for normal development.
Babbling in the Manual Mode: Evidence for the Ontogeny of Language
Authors: Petitto Laura Ann , Marentette Paula F.
Published: October 2006

Infant vocal babbling has been assumed to be a speech-based phenomenon that reflects the maturation of the articulatory apparatus responsible for spoken language production. Manual babbling has now been reported to occur in deaf children exposed to signed languages from birth. The similarities between manual and vocal babbling suggest that babbling is a product of an amodal, brain-based language capacity under maturational control, in which phonetic and syllabic units are produced by the infant as a first step toward building a mature linguistic system. Contrary to prevailing accounts of the neurological basis of babbling in language ontogeny, the speech modality is not critical in babbling. Rather, babbling is tied to the abstract linguistic structure of language and to an expressive capacity capable of processing different types of signals (signed or spoken).
Daylight Time-Resolved Photographs of Lightning
Authors: Orville Richard E. , Lala G. G. , Idone Vincent P.
Published: October 2006

Lightning dart leaders and return strokes have been recorded in daylight with both good spatial resolution and good time resolution as part of the Thunderstorm Research International Program. The resulting time-resolved photographs are apparently equivalent to the best data obtained earlier only at night. Average two-dimensional return stroke velocities in four subsequent strokes between the ground and a height of 1400 meters were approximately 1.3 × 10
8
meters per second. The estimated systematic error is 10 to 15 percent.
Radiocarbon Dating with Electrostatic Accelerators: Dating of Milligram Samples
Authors: Bennett C. L. , Beukens R. P. , Clover M. R. , Elmore D. , Gove H. E. , Kilius L. , Litherland A. E. , Purser K. H.
Published: October 2006

The recently developed direct counting technique for radiocarbon atoms has been used to measure the relative numbers of such atoms in various geological samples which had earlier been dated by the beta-ray counting method. Sample weights ranged from 3.5 to 15 milligrams. The dates determined by the two methods are consistent with each other. Further experience with the new method is also reported.
Economics of Nuclear Power
Authors: Rossin A. D. , Rieck T. A.
Published: October 2006

With 12 percent of U.S. electricity now being supplied by nuclear power, Commonwealth Edison has found nuclear plants to be good investments relative to other base load energy sources. The country's largest user of nuclear power, Commonwealth Edison, estimates that its commitment to nuclear saved its customers about 10 percent on their electric bills in 1977, compared to the cost with the next best alternative, coal. This advantage is seen as continuing, contrary to criticisms of the economics and reliability of nuclear power and claims that it has hidden subsidies. It is concluded that there is a need for both nuclear and coal and that government policy precluding or restricting either would be unwise.
Military Uses of Uranium: Keeping the U.S. Energy Accounts
Authors: Smith Kirk R.
Published: October 2006

Present accounts of U.S. energy consumption are incomplete in two ways: they include neither the direct military uses of nuclear energy nor the mostly military, nonfuel uses of uranium. Preliminary estimates indicate that significant distortions are created in the data on U.S. nuclear energy consumption patterns as a result of these omissions.
Larval Bivalve Shell Morphometry: A New Paleoclimatic Tool?
Authors: Lutz Richard A. , Jablonski David
Published: October 2006

The shells of the pelagic larvae of bivalve mollusks may be useful as paleoclimatic indicators. An inverse relationship between temperature and maximum size of larval shells within a particular population is reported for a number of Recent species. Changes in the dimensions of the prodissoconch-dissoconch boundary on juvenile specimens may reflect changes in the ambient temperature of marine environments.
Beryllium-10 Mass Spectrometry with a Cyclotron
Authors: Raisbeck G. M. , Yiou F. , Fruneau M. , Loiseaux J. M.
Published: October 2006

The Grenoble cyclotron has been used as a mass spectrometer to measure ratios of beryllium-10 to beryllium-9 of 10
–8
, 10
–9
, and 10
–10
in standardized beryllium oxide samples. Similar measurements can be used to determine cosmogenic beryllium-10 (half-life, 1.5 × 10
6
years) profiles in various geophysical reservoirs such as sea sediments and polar ice. This procedure can be used either to date such samples or to give information about geophysical and astrophysical phenomena that have influenced the beryllium-10 production rate in the past.
Volcanically Related Secular Trends in Atmospheric Transmission at Mauna Loa Observatory, Hawaii
Authors: Mendonca Bernard G. , Hanson Kirby J. , DeLuisi John J.
Published: October 2006

Twenty years of atmospheric transmission data from Mauna Loa Observatory show secular decreases at irregular intervals. In addition, a regular annual variation is present during unperturbed as well as perturbed periods. These variations in transmission can be measured to a few tenths of a percent from the data record. Transient decreases in transmission are strongly correlated with explosive volcanic eruptions that inject effluent into the stratosphere. Recovery from these ejections takes as much as 8 years and the recovery curve is linear. Observations in 1977 at Mauna Loa show that, for the first time since the Mount Agung eruption in 1963, the atmospheric transmission of direct-incidence solar irradiation at Mauna Loa returned to values measured in 1958 to 1962.
Oxygen and Carbon Isotopic Growth Record in a Reef Coral from the Florida Keys and a Deep-Sea Coral from Blake Plateau
Authors: Emiliani Cesare , Hudson J. Harold , Shinn Eugene A. , George Robert Y.
Published: October 2006

Carbon and oxygen isotope analysis through a 30-year (1944 to 1974) growth of
Montastrea annularis
from Hen and Chickens Reef (Florida Keys) shows a strong yearly variation in the abundances of both carbon-13 and oxygen-18 and a broad inverse relationship between the two isotopes. Normal annual dense bands are formed during the summer and are characterized by heavy carbon and light oxygen. "Stress bands" are formed during particularly severe winters and are characterized by heavy carbon and heavy oxygen. The isotopic effect of Zooxanthellae metabolism dominates the temperature effect on the oxygen-18/oxygen-16 ratio. The isotopic results on the deep-sea solitary coral
Bathypsammia tintinnabulum
, where Zooxanthellae are nonexistent, indicates that the abundance of the heavy isotopes carbon-13 and oxygen-18 is inversely related to the growth rate, with both carbon and oxygen approaching equilibrium values with increasing skeletal age.
Iron Ore: Energy, Labor, and Capital Changes with Technology
Authors: Kakela Peter J.
Published: October 2006

Resource gathering is depending on leaner crude ores. Iron ore mining typifies this trend. To make lean taconite iron ores useful required a technologic breakthrough—pelletization. The shift to iron ore pellets has the advantage that they require less energy and labor per ton of molten iron than high-grade naturally concentrated ores. Increased reliance on pellets causes a geographic shift of some jobs and environmental effects from blast furnaces to iron ore mines.
Polychlorinated Biphenyls: Transfer from Microparticulates to Marine Phytoplankton and the Effects on Photosynthesis
Authors: Harding Lawrence W. , Phillips John H.
Published: October 2006

Polychlorinated biphenyls (PCB's) initially associated with microparticulates are incorporated into marine diatom cells. The time course of transfer is rapid; equilibrium is attained within several hours. Assays with chlorophyll a fluorescence in vivo indicate that the transferred PCB's reach sites in the photosynthetic machinery that are sensitive to the effects of these compounds.
Phanerozoic Peridotitic and Pyroxenitic Komatiites from Newfoundland
Authors: Upadhyay H. D.
Published: October 2006

Peridotitic and highly magnesian pyroxenitic komatiites, thus far known to occur almost exclusively in the Archean (before 2.5 × 10
9
years ago) terranes, are reported from an Ordovician (0.5 × 10
9
years) ophiolite suite in Newfoundland. Their occurrence as pillow lavas or as chilled dikes, their possession of quench textures and geochemical parameters such as high contents of magnesium oxide, nickel, and chromium and low contents of titanium dioxide and potassium monoxide, low ratios of iron to iron plus magnesium, and values of the ratio of calcium oxide to aluminum oxide of close to unity demonstrate that they were formed through the rapid cooling of a highly mobile komatiitic melt. These features resemble those of many Archean peridotitic-pyroxenitic komatiites and indicate that the Archean-type magmatism did prevail in the younger segments of the earth's history although perhaps in a more erratic manner.
Fatal Sibling Aggression, Precocial Development, and Androgens in Neonatal Spotted Hyenas
Authors: Frank Laurence G. , Glickman Stephen E. , Licht Paul
Published: October 2006

Fatal neonatal sibling aggression is common in predatory birds but has not been previously reported in wild mammals. Spotted hyena females are strongly masculinized, both anatomically and behaviorally, apparently by high levels of androgens during ontogeny. Neonates display elevated androgen levels, precocial motor development, and fully erupted front teeth. Litters are usually twins, and siblings fight violently at birth, apparently leading to the death of one sibling in same-sex litters, whereas in mixed-sex litters both siblings usually survive.
Neutron Scattering of Solution-Grown Polymer Crystals: Molecular Dimensions Are Insensitive to Molecular Weight
Authors: Sadler D. M. , Keller A.
Published: October 2006

Neutron scattering gives information on molecular conformations in solid solutions of polymers of one isotope in another. Results on crystals of polyethylene grown from solution show a molecular dimension (in the form of a radius of gyration) that is almost invariant with the length of the chain. It is proposed that certain lengths of folded chains fold back onto themselves to form stacks of chain-folded ribbons ("superfolding").
Mars Gravity: High-Resolution Results from Viking Orbiter 2
Authors: Sjogren William L.
Published: October 2006

Doppler radio-tracking data have provided detailed measurements for a martian gravity map extending from 30° S to 65° N in latitude and through 360° of longitude. The feature resolution is approximately 500 kilometers, revealing a huge anomaly associated with Olympus Mons, a mascon in Isidis Planitia, and other anomalies correlated with volcanic structure. Olympus Mons has been modeled with a 600-kilometer surface disk having a mass of 8.7 × 10
21
grams
Magnetite in Freshwater Magnetotactic Bacteria
Authors: Frankel Richard B. , Blakemore Richard P. , Wolfe Ralph S.
Published: October 2006

A previously undescribed magnetotactic spirillum isolated from a freshwater swamp was mass cultured in the magnetic as well as the nonmagnetic state in chemically defined culture media. Results of Mössbauer spectroscopic analysis applied to whole cells identifies magnetite as a constituent of these magnetic bacteria.
Transovarial Transmission of Japanese Encephalitis Virus by Mosquitoes
Authors: Rosen Leon , Tesh Robert B. , Lien Jih Ching , Cross John H.
Published: October 2006

Female
Aedes albopictus
and
Aedes togoi
mosquitoes infected with Japanese encephalitis virus either by intrathoracic inoculation or by ingestion of a virus-sucrose-erythrocyte mixture transmitted the virus to a small percentage of their F
1
progeny. Adult F
1
female Aedes albopictus thus infected transmitted the virus in turn to newly hatched chickens by feeding on them.
Mercury Distribution in the Gulf Stream
Authors: Mukherji Prithviraj , Kester Dana R.
Published: October 2006

Measurements of reactive mercury in ocean water in the Gulf Stream at depths from 250 to 4460 meters revealed lower and more consistent concentrations than have been reported in the western Atlantic. The mean and standard deviation of 24 values in a vertical profile were 4.1 ± 1.0 nanograms per liter. A correlation was found between variations in mercury and silicate, suggesting a common link in their marine geochemistry.
Microbial Autotrophy: A Primary Source of Organic Carbon in Marine Sediments
Authors: Kepkay Paul E. , Cooke Robert C. , Novitsky James A.
Published: October 2006

The chemoautotrophic fixation of carbon dioxide by bacteria is responsible for an appreciable component of the organic carbon in a sulfide-rich marine mud. A peak of carbon dioxide fixation (at 40 centimeters subbottom) coincides with peaks in the organic carbon content, the ratio of carbon to nitrogen, and bacterial cell counts. Stimulation of fixation by thiosulfate and inhibition by anaerobic conditions implicate the chemoautotrophic sulfur bacteria as primary producers in this environment.
Nitrogen-Fixing
Anabaena
: Physiological Adaptations Instrumental in Maintaining Surface Blooms
Authors: Paerl Hans W. , Kellar Penelope E.
Published: October 2006

Both laboratory and in situ studies indicate that the nitrogen-fixing blue-green nuisance algae
Anabaena
spp. have developed adaptive means of dominating surface lake waters. During the dramatic diurnal shifts in surface light intensity and oxygen saturation accompanying blooms,
Anabaena
can overcome oxygen toxicity by sequential optimization of carbon dioxide and nitrogen fixation and by pigment alteration. These mechanisms allow optimal utilization of the radiant energy while minimizing competition for photoreductant between two main energy-demanding processes.
Science and Industry, Challenges of Antagonistic Interdependence
Authors: Drucker Peter F.
Published: October 2006

No one is responsible for the disenchantment of American science with its customers, government and industry, and of the customers with science. But the estrangement that has replaced the earlier relationship of mutual respect, while dangerous to both sides, is a mortal threat to American science.