bluuebunny/crossref_metadata_2025 huggingface dataset:
Supercooling of Water to -92°C Under Pressure
Authors: Kanno H. , Speedy R. J. , Angell C. A.
Published: October 2006

The temperature at which "clean" supercooled water freezes has been determined as a function of pressure up to 3 kilobars, using a differential thermal analysis technique on subdivided water samples. The supercooling limit of such samples, -38°C at normal pressure, is lowered by initial increase of pressure, reaching a minimum value of -92°C at 2.00 kilobars.
Viral Persistence in Neurons Explained by Lack of Major Histocompatibility Class I Expression
Authors: Joly Etienne , Mucke Lennart , Oldstone Michael B. A.
Published: October 2006

Viruses frequently persist in neurons, suggesting that these cells can evade immune surveillance. In a mouse model, 5 × 10
6
cytotoxic T lymphocytes (CTLs), specific for lymphocytic choriomeningitis virus (LCMV), did not lyse infected neurons or cause immunopathologic injury. In contrast, intracerebral injection of less than 10
3
CTL caused disease and death when viral antigens were expressed on leptomeningial and choroid plexus cells of the nervous system. The neuronal cell line OBL21 expresses little or no major histocompatibility (MHC) class I surface glycoproteins and when infected with LCMV, resisted lysis by virus-specific CTLs. Expression of MHC heavy chain messenger RNA was limited, but β
2
-microglobulin messenger RNA and protein was made normally. OBL21 cells were made sensitive to CTL lysis by transfection with a fusion gene encoding another MHC class I molecule. Hence, neuronal cells probably evade immune surveillance by failing to express MHC class I molecules.
Establishment of the Mediterranean Fruit Fly in California
Authors: Carey James R.
Published: October 2006

Principles of invasion biology are brought to bear on the question of whether the medfly is established in California. Since its first discovery in 1975, the pest has been captured in the Los Angeles Basin in nine separate years including every year from 1986 through 1990. The trend has become distinct—the intervals between captures are decreasing, the numbers captured are increasing, and the area over which they are detected is expanding. In addition, appearances are seasonal and captures in recent years have occurred in many of the same cities and neighborhoods where medflies were found several years before. Evidence suggests that the medfly may be established in the Los Angeles area and that previous eradication programs did not eradicate the medfly from California. It follows that detection, exclusion, and eradication protocols may need to be reexamined.
Cross-Regulatory Interactions Between the Proneural
achaete
and
scute
Genes of
Drosophila
Authors: Martínez Carmen , Modolell Juan
Published: October 2006

The
achaete
(
ac
) and
scute
(
sc
) genes of
Drosophila
allow cells to become sensory organ mother cells. Although
ac
and
sc
have similar patterns of expression, deletion of either gene removes specific subsets of sensory organs. This specificity was shown to reside in the peculiar regulation of
ac
and
sc
expression. These genes are first activated in complementary spatial domains in response to different cis-regulatory sequences. Each gene product then stimulates expression of the other gene, thus generating similar patterns of expression. Therefore, removal of one gene leads to the absence of both proneural gene products and sensory organs in the sites specified by its cis-regulatory sequences.
Arginyl Residues: Anion Recognition Sites in Enzymes
Authors: Riordan J. F. , McElvany K. D. , Borders C. L.
Published: October 2006

Chemical modification with 2,3-butanedione in borate buffer indicates that nine of ten glycolytic enzymes studied contain arginyl residues at their active sites. Fructose-1,6-diphosphatase also has arginines at its binding site for the allosteric inhibitor, adenosine monophosphate. These and other data suggest that, as a general rule, enzymes acting on anionic substrates or cofactors will probably contain arginyl residues as components of their ligand binding sites. This could account in part for the relatively infrequent occurrence of arginine in proteins.
Density-Dependent Natural Selection and Trade-Offs in Life History Traits
Authors: Mueller Laurence D. , Guo Pingzhong , Ayala Francisco J.
Published: October 2006

Theories of density-dependent natural selection state that at extreme population densities evolution produces alternative life histories due to trade-offs. The trade-offs are presumed to arise because those genotypes with highest fitness at high population densities will not also have high fitness at low density and vice-versa. These predictions were tested by taking samples from six populations of
Drosophila melanogaster
kept at low population densities (
r
-populations) for nearly 200 generations and placing them in crowded cultures (
K
-populations). After 25 generations in the crowded cultures, the derived
K
-populations showed growth rate and productivity that at high densities were elevated relative to the controls, but at low density were depressed.
Panhandling: Sharing of Resources
Authors: Lockard J. S. , McDonald L. L. , Clifford D. A. , Martinez R.
Published: October 2006

Panhandling was used to study sharing of resources. Male panhandlers were more successful in spring than in autumn. Female panhandlers were more successful than males in autumn. Panhandlers were generally successful only when submissively approaching individuals who were eating. Families and male-female pairs were resistant to panhandling. The results are discussed in terms of reciprocal altruism and kinship selection.
Solar Structure and Terrestrial Weather
Authors: Wilcox John M.
Published: October 2006

If there is indeed an effect of the variable sun on the weather, the physical cause for it remains quite elusive. We should keep in mind the possibility that there may be several causes and several effects. The situation may change through the 11-year sunspot cycle and the 22-year solar magnetic cycle, as well as on longer time scales.

Work is proceeding at a lively pace at the institutions mentioned in this article and at many others around the world. The Soviet Union has long had considerably more workers interested in this field than has any other country. A bilateral agreement between the Soviet Union and the United States has considerably increased the interactions between workers interested in this subject, including an exchange of extended visits between the two countries.

A detailed knowledge of solar causes of geomagnetic activity is only now beginning to emerge after many years of scientific efforts. This suggests that a possible successful solution to the sun-weather problem will require a similar magnitude of effort. We look forward with interest and optimism to the results of the next few years.
Courtship Differences in Male Ring Doves: Avoidance of Cuckoldry?
Authors: Erickson Carl J. , Zenone Patricia G.
Published: October 2006

Male ring doves exhibit less courtship and more aggressive behavior toward females that have recently associated with other males than to females that have been isolated. The difference in response may be related to the differing probability of cuckoldry.
Large-Scale and Automated DNA Sequence Determination
Authors: Hunkapiller T. , Kaiser R. J. , Koop B. F. , Hood L.
Published: October 2006

DNA sequence analysis is a multistage process that includes the preparation of DNA, its fragmentation and base analysis, and the interpretation of the resulting sequence information. New technological advances have led to the automation of certain steps in this process and have raised the possibility of large-scale DNA sequencing efforts in the near future [for example, 1 million base pairs (Mb) per year]. New sequencing methodologies, fully automated instrumentation, and improvements in sequencing-related computational resources may render genome-size sequencing projects (100 Mb or larger) feasible during the next 5 to 10 years.
Defining Protective Responses to Pathogens: Cytokine Profiles in Leprosy Lesions
Authors: Yamamura Masahiro , Uyemura Koichi , Deans Robert J. , Weinberg Kenneth , Rea Thomas H. , Bloom Barry R. , Modlin Robert L
Published: October 2006

The immunological mechanisms required to engender resistance have been defined in few infectious diseases of man, and the role of specific cytokines is unclear. Leprosy presents clinically as a spectrum in which resistance correlates with cell-mediated immunity to the pathogen. To assess in situ cytokine patterns, messenger RNA extracted from leprosy skin biopsy specimens was amplified by the polymerase chain reaction with 14 cytokine-specific primers. In lesions of the resistant form of the disease, messenger RNAs coding for interleukin-2 and interferon-γ were most evident. In contrast, messenger RNAs for interleukin-4, interleukin-5, and interleukin-10 predominated in the multibacillary form. Thus, resistance and susceptibility were correlated with distinct patterns of cytokine production.
The First Step in Vision: Femtosecond Isomerization of Rhodopsin
Authors: Schoenlein R. W. , Peteanu L. A. , Mathies R. A. , Shank C. V.
Published: October 2006

The kinetics of the primary event in vision have been resolved with the use of femtosecond optical measurement techniques. The 11-cisretinal prosthetic group of rhodopsin is excited with a 35-femtosecond pump pulse at 500 nanometers, and the transient changes in absorption are measured between 450 and 580 nanometers with a 10-femtosecond probe pulse. Within 200 femtoseconds, an increased absorption is observed between 540 and 580 nanometers, indicating the formation of photoproduct on this time scale. These measurements demonstrate that the first step in vision, the 11-cis→11-transtorsional isomerization of the rhodopsin chromophore, is essentially complete in only 200 femtoseconds.
Valid Climatological Data from Historical Sources by Content Analysis
Authors: Moodie D. W. , Catchpole A. J. W.
Published: October 2006

Content analysis is used to derive dates of freeze-up and break-up from historical descriptions of river estuaries on Hudson Bay between 1714 and 1871. Validity testing of these dates indicates that they are comparable with modern data. It is thus proposed that the method affords potential for the systematic retrieval of a broad array of environmental data from the historical past.
Man-Made Carbon Tetrachloride in the Atmosphere
Authors: Galbally I. E.
Published: October 2006

The emissions of man-made carbon tetrachloride and the rates of its removal from the atmosphere by natural sinks are evaluated. A large fraction, perhaps all of the carbon tetrachloride observed in the atmosphere, could be man-made, and carbon tetrachloride is a global atmospheric pollutant.
Preliminary Results from the Viking Orbiter Imaging Experiment
Authors: Carr Michael H. , Masursky Harold , Baum William A. , Blasius Karl R. , Briggs Geoffrey A. , Cutts James A. , Duxbury Thomas , Greeley Ronald , Guest John E. , Smith Bradford A. , Soderblom Laurence A. , Veverka Joseph , Wellman John B.
Published: October 2006

During its first 30 orbits around Mars, the Viking orbiter took approximately 1000 photographic frames of the surface of Mars with resolutions that ranged from 100 meters to a little more than 1 kilometer. Most were of potential landing sites in Chryse Planitia and Cydonia and near Capri Chasma. Contiguous high-resolution coverage in these areas has led to an increased understanding of surface processes, particularly cratering, fluvial, and mass-wasting phenomena. Most of the surfaces examined appear relatively old, channel features abound, and a variety of features suggestive of permafrost have been identified. The ejecta patterns around large craters imply that fluid flow of ejecta occurred after ballistic deposition. Variable features in the photographed area appear to have changed little since observed 5 years ago from Mariner 9. A variety of atmospheric phenomena were observed, including diffuse morning hazes, both stationary and moving discrete white clouds, and wave clouds covering extensive areas.
The Surface of Mars: There View from the Viking 1 Lander
Authors: Mutch Thomas A. , Binder Alan B. , Huck Friedrich O. , Levinthal Elliott C. , Liebes Sidney , Morris Elliott C. , Patterson William R. , Pollack James B. , Sagan Carl , Taylor Glenn R.
Published: October 2006

The first photographs ever returned from the surface of Mars were obtained by two facsimile cameras aboard the Viking 1 lander, including black-and-white and color, 0.12° and 0.04° resolution, and monoscopic and stereoscopic images. The surface, on the western slopes of Chryse Planitia, is a boulder-strewn deeply reddish desert, with distant eminences—some of which may be the rims of impact craters—surmounted by a pink sky. Both impact and aeolian processes are evident. After dissipation of a small dust cloud stirred by the landing maneuvers, no subsequent signs of movement were detected on the landscape, and nothing has been observed that is indicative of macroscopic biology at this time and place.
Hierarchical Relations Among Female Hanuman Langurs (Primates: Colobinae,
Presbytis entellus
)
Authors: Hrdy Sarah Blaffer , Hrdy Daniel B.
Published: October 2006

Female hierarchies are stable over short periods but fluctuate from year to year. In general, young females rise in rank over older and often larger female relatives, even though old females remain active in troop defense. This previously undescribed dominance system can be plausibly explained with reference to inclusive fitness theory and the concept of reproductive value.
Dependability of Wind Energy Generators with Short-Term Energy Storage
Authors: Sørensen Bent
Published: October 2006

Power fluctuations and power duration curves for wind energy generators, including energy storage facilities of a certain capacity, are compared to those of typical nuclear reactors. A storage system capable of delivering the yearly average power output for about 10 hours already makes the dependability of the wind energy system comparable to that of a typical nuclear plant.
The Viking Seismic Experiment
Authors: Anderson Don L. , Duennebier Frederick K. , Latham Gary V. , Toksöz M. Fafi , Kovach Robert L. , Knight Tony C. D. , Lazarewicz Andrew R. , Miller Wayne F. , Nakamura Yosio , Sutton George
Published: October 2006

A three-axis short-period seismometer is now operating on Mars in the Utopia Planitia region. The noise background correlates well with wind gusts. Although no quakes have been detected in the first 60 days of observation, it is premature to draw any conclusions about the seismicity of Mars. The instrument is expected to return data for at least 2 years.
The Viking Carbon Assimilation Experiments: Interim Report
Authors: Horowitz N. H. , Hobby G. L. , Hubbard J. S.
Published: October 2006

A synthesis of organic matter from atmospheric carbon monoxide or carbon dioxide, or both, appears to take place in the surface material of Mars at a low rate. The synthesis appears to be thermolabile and to be inhibited by moisture.
Factors Governing Tropospheric Mean Temperature
Authors: Newell Reginald E. , Weare Bryan C.
Published: October 2006

Two possible factors, which in addition to Pacific sea surface temperatures might affect the mean temperatures of the tropical troposphere are Atlantic sea surface temperatures and volcanic aerosol. The Mt. Agung eruption in March 1963 produced a decrease of about 0.5°C in the mean temperature of the tropical troposphere. The contribution of the Atlantic is not significant.
Molecular Basis of Gating Charge Immobilization in Shaker Potassium Channels
Authors: Bezanilla Francisco , Perozo Eduardo , Papazian Diane M. , Stefani Enrico
Published: October 2006

Voltage-dependent ion channels respond to changes in the membrane potential by means of charged voltage sensors intrinsic to the channel protein. Changes in transmembrane potential cause movement of these charged residues, which results in conformational changes in the channel. Movements of the charged sensors can be detected as currents known as gating currents. Measurement of the gating currents of the
Drosophila
Shaker potassium channel indicates that the charge on the voltage sensor of the channels is progressively immobilized by prolonged depolarizations. The charge is not immobilized in a mutant of the channel that lacks inactivation. These results show that the region of the molecule responsible for inactivation interacts, directly or indirectly, with the voltage sensor to prevent the return of the charge to its original position. The gating transitions between closed states of the channel appear not to be independent, suggesting that the channel subunits interact during activation.
The Anion Paradox in Sodium Taste Reception: Resolution by Voltage-Clamp Studies
Authors: Ye Qing , Heck Gerard L. , DeSimone John A.
Published: October 2006

Sodium salts are potent taste stimuli, but their effectiveness is markedly dependent on the anion, with chloride yielding the greatest response. The cellular mechanisms that mediate this phenomenon are not known. This "anion paradox" has been resolved by considering the field potential that is generated by restricted electrodiffusion of the anion through paracellular shunts between taste-bud cells. Neural responses to sodium chloride, sodium acetate, and sodium gluconate were studied while the field potential was voltage-clamped. Clamping at electronegative values eliminated the anion effect, whereas clamping at electropositive potentials exaggerated it. Thus, field potentials across the lingual epithelium modulate taste reception, indicating that the functional unit of taste reception includes the taste cell and its paracellular microenvironment.
Modulation of the Affinity of Integrin α
IIb
β
3
(GPIIb-IIIa) by the Cytoplasmic Domain of α
IIb
Authors: O'Toole Timothy E. , Mandelman David , Forsyth Jane , Shattil Sanford J. , Plow Edward F. , Ginsberg Mark H.
Published: October 2006

Intracellular signaling alters integrin adhesive functions in inflammation, immune responses, hemostasis, thrombosis, and retinal development. By truncating the cytoplasmic domain of α
IIb
, the affinity of integrin α
IIb
β
3
for ligand was increased. Reconstitution with the cytoplasmic domain from integrin α
5
did not reverse the increased affinity. Thus, the cytoplasmic domain of the α subunit of GPIIb-IIIa controls ligand binding affinity, which suggests mechanisms for inside-out transmembrane signaling through integrins. These findings imply the existence of hitherto unappreciated hereditary and acquired thrombotic disorders in humans.
Three Hypolipidemic Drugs Increase Hepatic Palmitoyl-Coenzyme A Oxidation in the Rat
Authors: Lazarow Paul B.
Published: October 2006

Male rats treated with clofibrate, tibric acid, or Wy-14,643 show an 11- to 18-fold increase in the capacity of their livers to oxidize palmitoyl-coenzyme A. This provides a plausible biochemical mechanism for the action of these hypolipidemic drugs in reducing lipid concentrations in the serum.
Binding of ARF and β-COP to Golgi Membranes: Possible Regulation by a Trimeric G Protein
Authors: Donaldson Julie G. , Kahn Richard A. , Lippincott-Schwartz Jennifer , Klausner Richard D.
Published: October 2006

The binding of cytosolic coat proteins to organelles may regulate membrane structure and traffic. Evidence is presented that a small guanosine triphosphate (GTP)-binding protein, the adenosine diphosphate ribosylation factor (ARF), reversibly associates with the Golgi apparatus in an energy, GTP, and fungal metabolite brefeldin A (BFA)-sensitive manner similar to, but distinguishable from, the 110-kilodalton cytosolic coat protein β-COP. Addition of βγ subunits of G proteins inhibited the association of both ARF and β-COP with Golgi membranes that occurred upon incubation with guanosine 5′-
O
-(3-thiotriphosphate) (GTP-γ-S). Thus, heterotrimeric G proteins may function to regulate the assembly of coat proteins onto the Golgi membrane.
Type-Specific Regulation of Adenylyl Cyclase by G Protein βγ Subunits
Authors: Tang Wei-Jen , Gilman Alfred G.
Published: October 2006

Heterotrimeric guanine nucleotide-binding regulatory proteins (G proteins) dissociate into guanosine triphosphate (GTP)-bound α subunits and a complex of β and γ subunits after interaction with receptors. The GTP-α subunit complex activates appropriate effectors, such as adenylyl cyclase, retinal phosphodiesterase, phospholipase C, and ion channels. G protein βγ subunits have been found to have regulatory effects on certain types of adenylyl cyclase. In the presence of G
sα
, the α subunit of the G protein that activates adenylyl cyclase, one form of adenylyl cyclase was inhibited by βγ, some forms were activated by βγ, and some forms were not affected by βγ. These interactions suggest mechanisms for communication between distinct signal-transducing pathways.
Glutamate Induces Calcium Waves in Cultured Astrocytes: Long-Range Glial Signaling
Authors: Cornell-Bell Ann H. , Finkbeiner Steven M. , Cooper Mark S. , Smith Stephen J.
Published: October 2006

The finding that astrocytes possess glutamate-sensitive ion channels hinted at a previously unrecognized signaling role for these cells. Now it is reported that cultured hippocampal astrocytes can respond to glutamate with a prompt and oscillatory elevation of cytoplasmic free calcium, visible through use of the fluorescent calcium indicator fluo-3. Two types of glutamate receptor—one preferring quisqualate and releasing calcium from intracellular stores and the other preferring kainate and promoting surface-membrane calcium influx—appear to be involved. Moreover, glutamate-induced increases in cytoplasmic free calcium frequently propagate as waves within the cytoplasm of individual astrocytes and between adjacent astrocytes in confluent cultures. These propagating waves of calcium suggest that networks of astrocytes may constitute a long-range signaling system within the brain.
Two Genes Control Seasonal Isolation in Sibling Species
Authors: Tauber Catherine A. , Tauber Maurice J. , Nechols James R.
Published: October 2006

Interspecific hybridization tests between
Chrysopa carnea
and
Chrysopa downesi
show that single allele differences at two unlinked autosomal loci cause large differences in photoperiodic responses. These differences produce asynchronous seasonal reproductive cycles, thus forming an effective temporal reproductive barrier between the two sympatric species. The results subserve the development of a genetic model for allochronic speciation.
Desulfurization of Coal by Use of Chemical Comminution
Authors: Howard Philip H. , Datta Rabinder S.
Published: October 2006

Chemical fracturing (comminution) of coal provides selective breakage, which may be used to liberate inorganic sulfur from it without resorting to excessive mechanical size reduction. The technique can be used for economic precombustion desulfurization and may have many other applications in coal utilization.
Developmental Neuroethology: Changes in Escape and Defensive Behavior During Growth of the Lobster
Authors: Lang Fred , Govind C. K. , Costello Walter J. , Greene Sharon I.
Published: October 2006

The changes in relative efficacy of two incompatible behaviors was investigated during growth of the lobster,
Homarus americanus
. In larval and early juvenile stages, physiological and morphological factors favor use of the escape response over defensive behavior. In large animals, defensive behavior is preferred almost exclusively to escape behavior unless the claws are lost. The interaction of escape and defensive behavior is modified by neural and morphological factors, which are dependent on the stage in the life cycle of the organism.
Chemical Bioinduction of Rubber in Guayule Plant
Authors: Yokoyama H. , Hayman E. P. , Hsu W. J. , Poling S. M. , Bauman A. J.
Published: October 2006

The treatment of young guayule plants with 2-(3,4-dichlorophenoxy)-triethylamine stimulated the accumulation of polyisoprenoid rubber in the stem and root tissues. This finding suggests that rubber productivity can be improved by the use of chemical agents on guayule and other rubber-forming plants.
Correction of CD18-Deficient Lymphocytes by Retrovirus-Mediated Gene Transfer
Authors: Wilson James M. , Ping April Joy , Krauss John C. , Mayo-Bond Laura , Rogers Clare E. , Anderson Donald C. , Todd Robert F.
Published: October 2006

Leukocyte adhesion deficiency (LAD) is an inherited disorder of leukocyte function caused by derangements in CD18 expression. The genetic and functional abnormalities in a lymphocyte cell line from a patient with LAD have been corrected by retrovirus-mediated transduction of a functional CD18 gene. Lymphocytes from patients with LAD were exposed to CD18-expressing retrovirus and enriched for cells that express CD11a and CD18 (LFA-1) on the cell surface. Molecular and functional analyses of these cells revealed (i) one copy of proviral sequence per cell, (ii) viral-directed CD18 RNA that exceeded normal endogenous levels, (iii) normal quantities of CD11a and CD18 protein on the cell surface, and (iv) reconstitution of LFA-1-dependent adhesive function.
Induction of Neonatal Tolerance to Mls
a
Antigens by CD8
+
T Cells
Authors: Webb Susan R. , Sprent Jonathan
Published: October 2006

Antigen-specific tolerance of T cells to minor lymphocyte stimulatory (Mls) antigens can be induced in mice by neonatal injection of foreign lymphohematopoietic cells. Although immune responses to Mls
a
antigens are controlled by B cells, CD8
+
T cells were the most effective cell type for induction of Mls
a
tolerance. Tolerance was evident in both thymus and lymph nodes and could be induced by as few as 2 × 10
4
CD8
+
T cells; these cells were 50 to 100 times as potent as CD4
+
cells or B cells in causing functional tolerance and deletion of V
β
6
+
T cells. Thus, intrathymic contact with antigens expressed on CD8
+
T cells may play an important role in controlling the normal development of tolerance.
Archean Microfossils Showing Cell Division from the Swaziland System of South Africa
Authors: Knoll Andrew H. , Barghoorn Elso S.
Published: October 2006

A newly discovered population of organic walled microstructures from the Swaziland System, South Africa, is considered to be biological on the following grounds: (i) the structures are carbonaceous and occasionally have internal organic contents; (ii) the population has a narrow unimodal size frequency distribution (average diameter, 2.5 micrometers; range, 1 to 4 micrometers); (iii) the structures are not strictly spherical, but are commonly flattened and folded like younger microfossils; (iv) the sedimentary context is consistent with biogenic origins; and (v) various stages of binary division are clearly preserved.
Spark Discharge: Application Multielement Spectrochemical Analysis
Authors: Walters John P.
Published: October 2006

Spark discharge is shown to be a cyclic process of energy dissipation, with one spark in a time-connected train influenced by its relation to predecessor sparks. Spectroscopic instruments having temporal, spatial, and spectral resolution indicate that the light emission is highly ordered with cylindrical symmetry about the current-conducting spark channel. The favored spatial coincidence is between the channel and the most highly ionized and most excited species sampled from the cathode, with less ionized and less excited species emitting farther outward. Light absorption occurs to such an extent that there are full line reversals in excited states of magnesium ions, distant from the channel. Schlieren data indicate a toroidal structure in the postdischarge environment. Charge transfer, Penning ionization, and sensitized fluorescence are thought to be the chemical mechanisms responsible for the spectroscopic topography. Experiments in spectrochemical analysis based on the topography and designed for increased sensitivity, reduced matrix effects, and simpler spectra are discussed.
Aggressive Chemical Mimicry by a Bolas Spider
Authors: Eberhard William G.
Published: October 2006

Mature female
Mastophora
sp. spiders attract prey with a volatile substance which apparently mimics the female sex attractant pheromone of the fall armyworm
Spodoptera frugiperda
(Lepidoptera). The rate of prey capture is similar to that of a conventional orb weaver of comparable body size.
Evidence for a Pollination-Drop Mechanism in Paleozoic Pteridosperms
Authors: Rothwell Gar W.
Published: October 2006

A noncellular substance containing pollen and spores has been discovered protruding from the micropyle of a seed fern ovule of Middle Pennsylvanian age. This provides direct evidence that pollination-drop mechanisms comparable to those of many extant gymnosperms characterize some Paleozoic pteridosperms.
Methylation-Sensitive Sequence-Specific DNA Binding by the c-Myc Basic Region
Authors: Prendergast George C. , Ziff Edward B.
Published: October 2006

The function of the c-Myc oncoprotein and its role in cell growth control is unclear. A basic region of c-Myc is structurally related to the basic motifs of helix-loop-helix (HLH) and leucine zipper proteins, which provide sequence-specific DNA binding function. The c-Myc basic region was tested for its ability to bind DNA by attaching it to the HLH dimerization interface of the E12 enhancer binding factor. Dimers of the chimeric protein, termed E6, specifically bound an E box element (GGCCACGTGACC) recognized by other HLH proteins in a manner dependent on the integrity of the c-Myc basic motif. Methylation of the core CpG in the E box recognition site specifically inhibited binding by E6, but not by two other HLH proteins. Expression of E6 (but not an E6 DNA binding mutant) suppressed the ability of c-
myc
to cooperate with H-
ras
in a rat embryo fibroblast transformation assay, suggesting that the DNA recognition specificity of E6 is related to that of c-Myc in vivo.
Adrenergic Stimulation of Taurine Transport by the Heart
Authors: Huxtable Ryan , Chubb James
Published: October 2006

A high-affinity transport system that is specific for β-amino acids has been delineated in rat hearts. This system transports the cardiotonic sulfonic amino acid taurine. β-Adrenergic stimulation increases the transport capacity without effect on α-amino acid uptake, as does stimulation with adenosine 3′,5′-monophosphate or theophylline. The existence of such an uptake system for taurine in the heart accounts for the high intra- to extracellular concentration gradient that is maintained, and suggests that cardiac stress is associated with increased taurine uptake. This may explain why taurine is the only amino acid to be markedly elevated in congestive heart failure. Taurine is a modifier of calcium fluxes in the heart, as are β-adrenergic agonists. The presence of this uptake system suggests a link between β-adrenergic stimulation of calcium and taurine fluxes.
The Composition of Phobos: Evidence for Carbonaceous Chondrite Surface from Spectral Analysis
Authors: Pang Kevin D. , Pollack James B. , Veverka Joseph , Lane Arthur L. , Ajello Joseph M.
Published: October 2006

A reflectance spectrum of Phobos (from 200 to 1100 nanometers) has been compiled from the Mariner 9 ultraviolet spectrometer, Viking lander imaging, and ground-based photometric data. The reflectance of the martian satellite is approximately constant at 5 percent from 1100 to 400 nanometers but drops sharply below 400 nanometers, reaching a value of 1 percent at 200 nanometers. The spectral albedo of Phobos bears a striking resemblance to that of asteroids (1) Ceres and (2) Pallas. Comparison of the reflectance spectra of asteroids with those of meteorites has shown that the spectral signature of Ceres is indicative of a carbonaceous chondritic composition. A physical explanation of how the compositional information is imposed on the reflectance spectrum is given. On the basis of a good match between the reflectance spectra of Phobos and Ceres and the extensive research that has been done to infer the composition of Ceres, it seems reasonable to believe that the surface composition of Phobos is similar to that of carbonaceous chondrites. This suggestion is consistent with the recently determined low density of Mars's inner satellite. Our result and recent Viking noble gas measurements suggest different modes of origin for Mars and Phobos.
Deficiencies of Glucosamine-6-Sulfate or Galactosamine-6-Sulfate Sulfatases Are Responsible for Different Mucopolysaccharidoses
Authors: Di Ferrante Nicola , Ginsberg Leonard C. , Donnelly Patricia V. , Di Ferrante Daniela T. , Caskey C. Thomas
Published: October 2006

[1-
3
H]Galactitol-6-sulfate,
N
-[1-
3
H]acetylgalactosaminitol-6-sulfate,
N
-[1-
3
H]acetylglucosaminitol-6-sulfate,
N
-acetylglucosamine-6-sulfate, and 6-sulfated tetrasaccharides from chondroitin-6-sulfate have been used for the measurementof 6-sulfatase activity of extracts of normal skin fibroblasts and of fibroblasts cultured from patients with genetic mucopolysaccharidoses.With these substrates, extracts of fibroblasts derived from Morquio patients lack or have greatly reduced activities for galactitol-6-sulfate,
N
-acetylgalactosaminitol-6-sulfate, and 6-sulfated tetrasaccharides but have normal activity for
N
-acetylglucosamine-6-sulfate and its alditol; those derived from a patient with a newly discovered mucopolysaccharidosis havegreatly reduced activity for
N
-acetylglucosamine-6-sulfate and its alditol but normal activity for galactitol-6-sulfate,
N
-acetylgalactosaminitol-6-sulfate, and the 6-sulfated tetrasaccharides. These findings demonstrate the existence of two differenthexosamine-6-sulfate sulfatases, specific for the glucose or galactose configuration of their substrates. Their respectivedeficiencies, causing inability to degrade keratan sulfate and heparan sulfate in one case and keratan sulfate and chondroitin-6-sulfatein the other, are responsible for different clinical phenotypes.
Determining the Season of Death of Mammal Teeth from Archeological Sites: A New Sectioning Technique
Authors: Bourque Bruce J. , Morris Kenneth , Spiess Arthur
Published: October 2006

Alternating translucent and opaque bands on the roots of mammal teeth are used to determine the age and season of death. These structures are preserved in teeth from archeological sites. However, the standard sectioning technique, which includes decalcification, often destroys archeological specimens. A new, less destructive technique provides analyzable solid sections at costs comparable to decalcification.
Coexistence of Clones in a Heterogeneous Environment
Authors: Vrijenhoek RC.
Published: October 2006

Two genetically distinct clones of the asexual triploid fish
Poeciliopsis 2 monacha-lucida
inhabit the Rio del Fuerte of northwestern Mexico. Their coexistence apparently depends on feeding specializations that result in partitioning of the limited food resources in the desert streams. The findings suggest that these asexual organisms have sufficient clonal diversity to occupy a broad, heterogeneous, adaptive zone.
Fuels from Biomass: Integration with Food and Materials Systems
Authors: Lipinsky E. S.
Published: October 2006

The development of fuels from biomass can lead naturally to dispersed facilities that incorporate food or materials production (or both) with fuel production, forming adaptive systems that can be modified to meet evolving needs and constraints. The technology that is appropriate to each system needs to be worked out, taking into account associated food and materials opportunities in order to decrease the ultimate cost of energy delivered to the consumer. I analyze possible systems based on sugarcane, corn, and guayule.
Solar Energy for Village Development
Authors: Brown Norman L. , Howe James W.
Published: October 2006

The National Academy of Sciences held a joint workshop with the Government of Tanzania last August on the potential of solar energy for the villages of that country. Costs of five solar technologies (mini-hydroelectric generators, wind, methane generation from organic wastes, photovoltaic cells, and flat-plate solar collectors) were compared with costs of diesel-generated electricity and with electricity from the national grid. Each of the five technologies is either now competitive with diesel or will be in a few years. Although the figures presented are not conclusive since they are derived from calculations rather than an actual test, the results are encouraging enough to warrant serious testing in Third World villages.
The Cluster Concept in Multiple Hadron Production
Authors: Dremin I. M. , Quigg C.
Published: October 2006

The general features of high-energy collisions of elementary particles are outlined. It is argued that multiple production occurs through the production of hadronic clusters. The history and present status of the cluster concept are surveyed.
Lunar Tidal Acceleration Determined from Laser Range Measures
Authors: Calame Odile , Mulholland J. Derral
Published: October 2006

Lunar laser range measures covering the period 1969 to 1976 have been used to determine the anomalous secular acceleration in the mean longitude of the moon, commonly attributed to the effect of tidal friction in the earth. The acceleration determined is –24.6 ± 1.6 arc seconds per century squared, against an atomic time scale, where the uncertainty is the formal standard deviation of the solution. The realistic uncertainty is surely larger, as evidenced by the ensemble of solutions performed with various models and observation sets. The determined value is in good agreement with the conventional value and with several recent determinations by other methods. An attempt to determine the rate of change of the mean distance, essential for separating the tidal effect from a time variation of the gravitational constant, yielded no significant result, because the observations still span too short a time.
Color and Constitution: One Hundred Years of Research
Authors: Dähne Siegfried
Published: October 2006

Useful theories and models of the color and constitution of unsaturated organic compounds have been sought for more than a century. The promises of quantum chemistry have not yet been realized satisfactorily. The polymethine concept, a modern chemical theory of constitution, is an auspicious development.
Recent Biogenic Phosphorite: Concretions in Mollusk Kidneys
Authors: Doyle Larr J. , Blake Norman J. , Woo C. C. , Yevich Paul
Published: October 2006

Phosphorite concretions have been detected in the kidneys of two widespread species of mollusks,
Mercenaria mercenaria
and
Argopecten irradians
, which have relatively high population densities. These concretions are the first documentation of the direct biogenic formation of phosphorite grains. The concretions are principally amorphous calcium phosphate, which upon being heated yields an x-ray diffraction pattern which is essentially that of chlorapatite. These concretions appear to be a normal formation of the excretory process of mollusks under reproductive, environmental, or pollutant-induced stress. Biogenic production of phosphorite concretions over long periods of time and diagenetic change from amorphous to crystalline structure, coupled with secondary enrichment, may account for the formation of some marine phosphorite deposits which are not easily explained by the chemical precipitation-replacement hypothesis.
A New Method for Carbon Isotopic Analysis of Protein
Authors: Nelson D. E.
Published: October 2006

The reaction of ninhydrin with amino acids can be used in carbon isotopic studies of protein. The reaction can be applied to extract as carbon dioxide only peptide-bonded carbon in proteinaceous material, thus avoiding most, if not all, contaminants. Test radiocarbon dates on ancient bone indicate that the method provides reliable ages, and stable carbon isotopic data suggest that our understanding of isotopic dietary reconstruction needs detailed examination. The technique should also be useful in biochemical tracing experiments and in global carbon budget studies, and the underlying principle may be applicable to other isotopes and molecules.
Tunicate Eggs Utilize Ammonium Ions for Flotation
Authors: Lambert Charles C. , Lambert Gretchen
Published: October 2006

Unlike most solitary ascidians,
Corella willmeriana
retains its eggs and embryos well past hatching. The early stages float to the top of the enlarged atrium from which they cannot escape. Ammonium ions replace other more dense substances in the cell sap of the float cells surrounding the embryo. Energy derived from glycolysis but not mitochondrial processes supports this process.
Aleuts, Sea Otters, and Alternate Stable-State Communities
Authors: Simenstad Charles A. , Estes James A. , Kenyon Karl W.
Published: October 2006

Reexamination of stratified faunal components of a prehistoric Aleut midden excavated on Amchitka Island, Alaska, indicates that Aleut prey items changed dramatically during 2500 years of aboriginal occupation. Recent ecological studies in the Aleutian Islands have shown the concurrent existence of two alternate stable nearshore communities, one dominated by macroalgae, the other by epibenthic herbivores, which are respectively maintained by the presence or absence of dense sea otter populations. Thus, rather than cultural shifts in food preference, the changes in Aleut prey were probably the result of local overexploitation of sea otters by aboriginal Aleuts.
Sharpening Stellar Images
Authors: Buffington Andrew , Crawford Frank S. , Pollaine Stephen M. , Orth Charles D. , Muller Richard A.
Published: October 2006

Atmospherically induced phase perturbations have for years limited the resolution of large optical astronomical telescopes. A prototype telescope system with six movable elements has successfully corrected these phase perturbations. This use of real-time image sharpening has restored stellar images to the diffraction limit (in one dimension) for a 30-centimeter telescope. The double-star image presented indicates that the bulk of the atmospherically induced wave-front phase change occurred within 2 kilometers of the telescope. This implies that, at least for conditions similar to those of our measurement, real-time correction can be accomplished simultaneously for a region at least several arc seconds in angular size. With the present apparatus the technique should be practical for objects as dim as fifth magnitude, and with improvements the technique holds the promise of active image restoration for objects as dim as ninth magnitude.
High-Pressure Physics: Sustained Static Generation of 1.36 to 1.72 Megabars
Authors: Mao H. K.
Published: October 2006

The pressure in experiments with the diamond-window pressure cell exceeded 1.7 megabars (at 25°C). This is the highest sustained pressure ever generated under static conditions where the pressure in the sample itself was measured. At 1.72 megabars, macroscopic flow of one of the diamond pressure faces was observed.
Absence of Microorganisms in Crustacean Digestive Tracts
Authors: Boyle Paul J. , Mitchell Ralph
Published: October 2006

Two marine and one terrestrial wood-boring isopod species and one wood-inhabiting amphipod species maintain a digestive tract free of microorganisms. Digestive tracts examined in toto with the scanning electron microscope were devoid of microorganisms. In contrast, the outer exoskeleton surfaces of these crustaceans support a dense bacterial flora. Observations of the hindgut of termites revealed a diverse gut microflora as expected.
The Compleat Angler: Aggressive Mimicry in an Antennariid Anglerfish
Authors: Pietsch Theodore W. , Grobecker David B.
Published: October 2006

A case of aggressive mimicry is described in which an anglerfish of the genus
Antennarius
(order Lophiiformes) utilizes a lure that mimics a small fish. The lure provides not only a highly attractive visual cue but presumably also a low-frequency pressure stimulus for potential prey with a minimum of energy expenditure.
Competitive Interactions Between Neotropical Pollinators and Africanized Honey Bees
Authors: Roubik David W.
Published: October 2006

The Africanized honey bee, a hybrid of European and African honey bees, is thought to displace native pollinators. After experimental introduction of Africanized honey bee hives near flowers, stingless bees became less abundant or harvested-less resource as visitation by Africanized honey bees increased. Shifts in resource use caused by colonizing Africanized honey bees may lead to population decline of Neotropical pollinators.
Silicate Spherules from Deep-Sea Sediments: Confirmation of Extraterrestrial Origin
Authors: Ganapathy R. , Brownlee D. E. , Hodge P. W.
Published: October 2006

Silicate spherules produced by atmospheric melting of meteoric bodies are probably the most common form of extraterrestrial material on the earth. It has never been possible to positively identify such particles although it has been known for more than a century that silicate spherules of suspected extraterrestrial origin are present in deep-sea sediments. One such spherule has been identified as definitely extraterrestrial since its abundances of nonvolatile trace elements closely match those of primitive solar system material.
Particle Capture by a Pacific Brittle Star: Experimental Test of the Aerosol Suspension Feeding Model
Authors: LaBarbera Michael
Published: October 2006

Ophiopholis aculeata
, a suspension feeding brittle star, is capable of removing artificial particles from seawater by some mechanism or mechanisms other than sieving; the animal can capture a finite proportion of particles in all size classes available from at least 30 to 360 micrometers in diameter. A marked shift in the size distribution of particles caught by the animal toward larger particle sizes agrees with predictions derived from aerosol filtration theory. Adhesion of particles to the tube feet is strongly dependent on the presence of fixed charged groups on the surface of the particles.
The Pecked Cross Symbol in Ancient Mesoamerica
Authors: Aveni Anthony F. , Hartung Horst , Buckingham Beth
Published: October 2006

Attention is directed to a design, possibly of Teotihuacan origin, carved both in rock and in the floors of ceremonial buildings throughout ancient Mesoamerica. Consisting generally of a double circular pattern centered on a set of orthogonal axes, the so-called pecked cross or quartered circle figure is shown to exhibit a remarkable consistency in appearance throughout its 29 reported locations, thus suggesting that it was not perfunctory. The metric properties of the symbols gleaned from field surveys are delineated, and several interpretations of their possible functions are discussed. These symbols may have been intended as astronomical orientational devices, surveyor's bench marks, calendars, or ritual games. Evidence is presented which implies that more than one and perhaps all of these functions were employed simultaneously, a view which is shown to be consistent with the cosmological attitude of the pre-Columbian people.
Caste in a Primitive Ant: Absence of Age Polyethism in
Amblyopone
Authors: Traniello James F. A.
Published: October 2006

Polyethism, the division of labor among members of a colony, is based on worker age and size in ants. In the ponerine species
Amblyopone pallipes
worker behavior is independent of age, therefore temporal castes, or groups of age-related task specialists, do not exist. This primitive caste system, previously unknown in ants, appears to be correlated with the peculiar characteristics of the life history and ecology of
Amblyopone
.
Calcium-Induced Contraction of the Rhizoplast of a Quadriflagellate Green Alga
Authors: Salisbury J. L. , Floyd G. L.
Published: October 2006

The rhizoplast of
Platymonas subcordiformis
is a contractile organelle. Cyclic contraction and extension are induced by incubating the organism in solutions containing calcium and adenosine triphosphate. Rhizoplast contraction is functionally linked to flagellar activity.