bluuebunny/crossref_metadata_2025 huggingface dataset:
Subunit Communication in the Anthranilate Synthase Complex from
Salmonella typhimurium
Authors: Caligiuri Maureen G. , Bauerle Ronald
Published: October 2006

The anthranilate synthase-phosphoribosyl transferase complex of the tryptophan biosynthetic pathway in
Salmonella typhimurium
is an allosteric, heterotetrameric (TrpE
2
-TrpD
2
) enzyme whose multiple activities are negatively feedback-regulated by L-tryptophan. A hybrid complex containing one catalytically active, feedback-insensitive and one catalytically inactive, feedback-sensitive mutant TrpE subunit was assembled in vitro and used to investigate communication between regulatory and catalytic sites located on different subunits. The properties of the hybrid complex demonstrate that the binding of a single inhibitor molecule to one TrpE subunit is sufficient for the propagation of a conformational change that affects the active site of the companion subunit.
Acid Precipitation in the Western United States
Authors: Lewis William M. , Grant Michael C.
Published: October 2006

Precipitation chemistry data from a rural area at an elevation of 2900 meters near the Continental Divide in Colorado show unexpectedly low
p
H values for bulk precipitation. A significant downward trend in
p
H over the last 3 years is associated with increasing amounts of nitric acid in precipitation.
Racemization of Amino Acids in Dipeptides Shows COOH > NH
2
for Non-Sterically Hindered Residues
Authors: Smith Grant Gill , de Sol Beatriz Silva
Published: October 2006

The relative rates of racemization for amino acid residues at the NH
2
and COOH ends of 37 different dipeptides were determined. In nine dipeptides containing alanine, leucine, phenylalanine, aspartic acid, and methionine, the amino acid residue racemized faster at the COOH-terminal position than at the NH
2
-terminal position (COOH > NH
2
). The sterically hindered amino acids isoleucine and valine showed NH
2
> COOH. Six proline dipeptides showed NH
2
> COOH. Intramolecular effects have been invoked to explain these surprising results.
Radon Anomaly: A Possible Precursor of the 1978 Izu-Oshima-kinkai Earthquake
Authors: Wakita Hiroshi , Nakamura Yuji , Notsu Kenji , Noguchi Masayasu , Asada Toshi
Published: October 2006

Precursory changes in the radon concentration of groundwater were observed prior to the Izu-Oshima-kinkai earthquake (magnitude 7.0) 14 January 1978. The distance from the epicenter to a continuous radon-monitoring station at Nakaizu was about 25 kilometers. A sudden drop and a subsequent increase in the radon concentration recorded on 9 January 1978 were significant. The size of the spike-like change was about 15 percent. After the earthquake, a remarkable increase in the radon concentration occurred.
Dynamic Compression of Earth Materials
Authors: Ahrens Thomas J.
Published: October 2006

Shock wave techniques have been used to investigate the pressure-density relations of metals, silicates, and oxides over the entire range of pressures present in the earth (3.7 × 10
6
bars at the center). In many materials of geophysical interest, such as iron, wüstite, calcium oxide, and forsterite, major shock-induced phase changes dominate the compression behavior below pressures of 10
6
bars. The shock wave data for the high-pressure phases of these minerals lead to important inferences about the composition of the lower mantle and outer, liquid core of the earth. The lower mantle of the earth appears to have a slightly higher density than is inferred to correspond to the behavior of an olivine-rich assemblage of the same composition as the upper mantle. The core has a density some 10 percent less than that of pure iron and may have 9 to 12 percent sulfur or about 8 percent oxygen by weight.
Gutless Bivalves
Authors: Reid Robert G. B. , Bernard Frank R.
Published: October 2006

A new benthic species of the protobranch bivalve genus
Solemya
, from the northeastern Pacific Ocean, lacks a gut. It has no internal digestive enzymatic apparatus; nor is there any provision for the secretion of enzymes into the mantle cavity for extraorganismic digestion. The most likely nutritional mechanism for such an animal is the active absorption of dissolved organic molecules from the environment by the large ctenidial lamellae. These are well provided with blood, cleansed of sediment by cilia, and have phosphatases in their epithelial cells.
Solemya borealis
may also be gutless.
Do Corals Lie About Their Age? Some Demographic Consequences of Partial Mortality, Fission, and Fusion
Authors: Hughes T. P. , Jackson J. B. C.
Published: October 2006

Population dynamics of corals and other colonial animals are complicated by their modular construction and growth. Partial colony mortality, colony fission, and colony fusion distort any simple relationship between size and age among reef corals.
Pollen Tube Growth Rates in
Zea mays
: Implications for Genetic Improvement of Crops
Authors: Ottaviano Ercole , Sari-Gorla Mirella , Mulcahy David L.
Published: October 2006

Speed of pollen tube growth is positively correlated with the quality of the resultant sporophytic generation. Therefore, gametophytic competition may be an important adaptive mechanism. Furthermore, pollen tube growth rates may be used to predict the quality of F
1
crosses in crop species.
Aseismic Uplift in Southern California: An Alternative Interpretation
Authors: Jackson David D. , Lee Wook B. , Liu Chi-Ching
Published: October 2006

The previously reported uplift in southern California may have resulted from systematic errors in leveling rather than tectonic activity. Errors are inferred from correlation between changes in elevation and topography at short and long wavelengths. Corrected data show no significant vertical motion except at the time of the San Fernando earthquake. Possible sources of error include inadequate rod calibration and refraction.
Intermediate Bosons: Weak Interaction Couriers
Authors: Hung P. Q. , Quigg C.
Published: October 2006

Recent progress toward a complete theory of the weak interactions has led to sharper predictions for the properties of the hypothetical weak-force particles known as intermediate bosons. The history of speculations about intermediate bosons is briefly summarized and the (as yet negative) searches carried out for these particles are reviewed. Prospects for future searches—both direct and indirect—are surveyed, and the consequences of finding the expected or unexpected are noted.
Phase Transitions, Critical Phenomena, and Instabilities
Authors: Fleury Paul A.
Published: October 2006

Transformations among many of the diverse states of matter arise from microscopic interactions involving very many (approximately 10
23
) constituent particles and result in dramatic changes in macroscopic properties. The values of some physical parameters vanish, while others approach infinity. These changes and their evolution are strikingly similar in systems as apparently different as liquids, magnets, superconductors, ferroelectrics, and liquid crystals, which suggests that there is an underlying unity to phase transition phenomena. The basis and extent of this unity are reviewed for many-body systems in equilibrium, and analogies with instability phenomena in systems far from equilibrium (such as lasers, fluid flows, and avalanche electronic devices) are pointed out.
On the Sources of Summertime Haze in the Eastern United States
Authors: Wolff George T. , Kelly Nelson A. , Ferman Martin A.
Published: October 2006

The summertime haze transported from the Gulf Coast northward in maritime tropical air masses is partially formed from emissions in the midwestern and northeastern United States. Several cases are documented in which sulfate particulates, formed from emissions in the Midwest and Northeast, traveled to the Gulf of Mexico and, in some cases, returned to their source regions.
Methane Production from Acetate and Associated Methane Fluxes from Anoxic Coastal Sediments
Authors: Sansone Francis J. , Martens Christopher S.
Published: October 2006

The apparent microbial conversion of acetate to methane ranges seasonally from 0.7 to 88 micromoles per liter of whole wet sediment per hour in the top 5 centimeters of methane-producing sediments underlying sulfate-reducing sediments in Cape Lookout Bight, North Carolina. The associated methane flux across the sediment-water interface into overlying waters exhibits the same seasonal pattern. Significant methane production from acetate is observed only in sulfate-depleted sediments.
Absorption of Visible Radiation by Aerosols in the Volcanic Plume of Mount St. Helens
Authors: Ogren J. A. , Charlson R. J. , Radke L. F. , Domonkos S. K.
Published: October 2006

Samples of particles from Mount St. Helens were collected in both the stratosphere and troposphere for measurement of the light absorption coefficient. Results indicate that the stratospheric dust had a small but finite absorption coefficient ranging up to 2 × 10
–7
per meter at a wavelength of 0.55 micrometer, which is estimated to yield an albedo for single scatter of 0.98 or greater. Tropospheric results showed similar high values of an albedo for single scatter.
Fate and Transport of Dieldrin in Coralville Reservoir: Residues in Fish and Water Following a Pesticide Ban
Authors: Schnoor Jerald L.
Published: October 2006

A model for the fate and transport of pesticide has been calibrated with field data from 1968 to 1978. The results have aided in a management decision to lift a commercial fishing ban in Coralville Reservoir, eastern Iowa. Dieldrin residues in fish, sediment, and water are all declining at about 15 percent per year. Approximately 50 percent of the pesticide load is exported from the reservoir in the outflow, 40 percent undergoes sedimentation, and 10 percent enters the fish.
Separation of Calcium Isotopes by Liquid Phase Thermal Diffusion
Authors: Rutherford W. M. , Laughlin K. W.
Published: October 2006

Significant separation of the isotopes of calcium was obtained by thermogravitational thermal diffusion of an aqueous calcium nitrate solution. A flow of solvent was used to partially offset the large solute-solvent separation effect in the experimental column. Further development of this technique may lead to separation of the isotopes of calcium and of other elements on a practical scale.
Brachiopods in Mud: Resolution of a Dilemma
Authors: Richardson Joyce R.
Published: October 2006

Assumptions made from studies of sparse living faunas of brachiopods, namely, that they are intolerant of mud, that the free-lying habit is confined to species without pedicles, and that the pedicle of articulate brachiopods is uniform in structure and function, do not withstand critical examination. Studies in New Zealand show that some species in the same area occur in both attached and free-lying populations. Individuals cannot always be differentiated morphologically, but the structure of populations from hard and soft substrates is distinctive. Attachment to a substrate appears to be a larval rather than an adult requirement in most species.
Alkaline Phosphatase in Epstein-Barr Viral Nuclear Antigen—Positive Cell Lines
Authors: Karpas A. , Hayhoe F. G. J. , Greenberger J. , Neumann H.
Published: October 2006

The production and nature of alkaline phosphatase were studied in Epstein-Barr viral nuclear antigen-positive, surface membrane immunoglobulin-negative cell lines established from two patients, one with acute myeloid leukemia and one with acute lymphoblastic leukemia. The acute myeloid leukemia-derived cells contained myeloid alkaline phosphatase, while the acute lymphoblastic leukemia-derived cells contained lymphoid alkaline phosphatase. The presence of the myeloid-specific enzyme in a surface membrane immunoglobin-negative cell line suggests that the line is composed of myeloid precursor cells and that such cells may be susceptible to infection with Epstein-Barr virus.
Metalloantibodies
Authors: Iverson Brent L. , Iverson Sheila A. , Roberts Victoria A. , Getzoff Elizabeth D. , Tainer John A. , Benkovic Stephen J. , Lerner Richard A.
Published: October 2006

A metalloantibody has been constructed with a coordination site for metals in the antigen binding pocket. The Zn(II) binding site from carbonic anhydrase B was used as a model. Three histidine residues have been placed in the light chain complementarity determining regions of a single chain antibody molecule. In contrast to the native protein, the mutant displayed metal-dependent fluorescence-quenching behavior. This response was interpreted as evidence for metal binding in the three-histidine site with relative affinities in the order Cu(II) > Zn(II) > Cd(II). The presence of metal cofactors in immunoglobulins should facilitate antibody catalysis of redox and hydrolytic reactions.
Dominance Hierarchies in
Leptothorax
Ants
Authors: Cole Blaine J.
Published: October 2006

The social organization of
Leptothorax allardycei
is unique among ant species thus far studied. The workers form linear dominance hierarchies characterized by routine displays of dominance, avoidance behavior, and even fighting. The high-ranking ants are favored in liquid food exchange, have greater ovarian development, and produce 20 percent of the eggs.
Energetic Charged Particles in Saturn's Magnetosphere: Voyager 1 Results
Authors: Vogt R. E. , Chenette D. L. , Cummings A. C. , Garrard T. L. , Stone E. C. , Schardt A. W. , Trainor J. H. , Lal N. , McDonald F. B.
Published: October 2006

Voyager 1 provided the first look at Saturn's magnetotail and magnetosphere during relatively quiet interplanetary conditions. This report discusses the energetic particle populations of the outer magnetosphere of Saturn and absorption features associated with Titan and Rhea, and compares these observations with Pioneer 11 data of a year earlier. The trapped proton fluxes had soft spectra, represented by power laws
E
–γ
in kinetic energy
E
, with γ ∼ 7 in the outer magnetosphere and γ ∼9 in the magnetotail. Structure associated with the magnetotial was observed as close as 10 Saturn radii (
R
s
) on the outbound trajectory. The proton and electron fluxes in the outer magnetosphere and in the magnetotail were variable and appeared to respond to changes in interplanetary conditions. Protons with energies ≥ 2 million electron volts had free access to the magnetosphere from interplanetary space and were not stably trapped outside ∼ 7.5
R
s
.
Uninfected Cells of Soybean Root Nodules: Ultrastructure Suggests Key Role in Ureide Production
Authors: Newcomb Eldon H. , Tandon Shiv R.
Published: October 2006

In soybean root nodules, which export recently fixed nitrogen mainly as the ureides allantoin and allantoic acid, cells uninfected by rhizobia undergo a pronounced ultrastructural differentiation not shown by the infected cells, including enlargement of the microbodies and proliferation of smooth endoplasmic reticulum. Since some of the enzymes contributing to ureide synthesis occur in these subcellular components in root nodule preparations, the uninfected cells may participate in ureide synthesis and thus play an essential role in the symbiosis between host and bacterium.
Solar Photovoltaic Power Systems: Will They Reduce Utility Peaking Requirements?
Authors: Mueller R. O. , Cha B. K. , Giese R. F.
Published: October 2006

From an analysis of the long-run electric generating requirements of several representative utilities, it is concluded that the energy supplied by solar photovoltaic power devices will displace primarily base-load, and to a lesser extent intermediate, generating plants, even at relatively modest penetrations corresponding to several percent of the utility peak load. Attaching photovoltaic devices to the utility grid will not yield significant fuel oil savings over the long run, in which utilities approach the economic optimum generating mix, and will increase peak plant requirements. Utility capacity and fuel savings of photovoltaic devices are reported both for the case without storage and for the case in which the utility has access to load-leveling storage.
Hemoglobin Kinetics of the Galápagos Rift Vent Tube Worm
Riftia pachyptila
Jones (Pogonophora; Vestimentifera)
Authors: Wittenberg Jonathan B. , Morris Roger J. , Gibson Quentin H. , Jones Meredith L.
Published: October 2006

Kinetics of the reactions of
Riftia pachyptila
hemoglobin with oxygen were followed spectrophotometrically by stopped-flow and laser flash photolysis techniques. The rate of oxygen dissociation increases eightfold over the range of 5° to 20°C (
k
= 2.2 sec
–1
at 10°C). Oxygen recombination after flash photolysis was biphasic. The rates of both slow and fast phases of the reaction were independent of temperature from 0° to 20°C (
k′
fast
= 7 × 10
6
;
k′
slow
= 1 × 16
6
liter mole
–1
sec
–1
). As the oxygen affinity is relatively temperature independent, analysis in terms of the two-state model of cooperativity requires that the conformational equilibrium constant
L
decrease by about 50-fold between 3° and 15°C.
The Short-Term Temporal Spectrum of Precipitable Water Vapor
Authors: Hogg D. C. , Guiraud F. O. , Sweezy W. B.
Published: October 2006

Short-term power spectra of the fluctuations in the precipitable water vapor measured with a dual-channel microwave radiometer are presented. The spectra, taken over 34-hour sampling periods, encompass periodicities from 1 day to about 10 minutes. The fluctuation power is associated with the average precipitable water vapor for the sampling period. The background noise spectrum of the radiometric instrument is also discussed.
Subseabed Disposal of Nuclear Wastes
Authors: Hollister Charles D. , Anderson D. Richard , Health G. Ross
Published: October 2006

Fine-grained clay formations within stable (predictable) deep-sea regions away from lithospheric plate boundaries and productive surface waters have properties that might serve to permanently isolate radioactive waste. The most important characteristics of such clays are their vertical and lateral uniformity, low permeability, very high cation retention capacity, and potential for self-healing when disturbed. The most attractive abyssal clay formation (oxidized red clay) covers nearly 30 percent of the sea floor and hence 20 percent of the earth's surface.
Archeological Evidence for Pimple (Pralrie) Mound Genesis
Authors: Aten Lawrence E. , Bollich Charles N.
Published: October 2006

Archeological deposits have been discovered in three pimple mounds on the upper Texas coast. Such incorporation indicates that (i) these particular mounds are aggradational rather than erosional in origin; (ii) mound formation continued until at least A.D. 1100 to 1200; (iii) each mound took 300 to 500 years to form; (iv) mounds within the same mound field did not form simultaneously; (v) certain Gulf Coast pimple mounds have archeological research potential; and (vi) archeological data also offer a means for investigating mound formation.
Mating Preferences Are Not Predictive of the Direction of Evolution in Experimental Populations of
Drosophila
Authors: Markow Therese Ann
Published: October 2006

The general applicability of two models used in predicting evolutionary directions from asymmetry in reproductive isolation was tested in the laboratory. In mate preference tests with strains of
Drosophila melanogaster
whose ancestral and derived relationships were known, no correspondence was found between sexual isolation and direction of evolution.
Lamellar Twinning Explains the Nearly Racemic Composition of Chiral, Single Crystals of Hexahelicene
Authors: Green Bernard S. , Knossow Marcel
Published: October 2006

Solvent etching of single crystals of hexahelicene grown from a racemic solution reveals an unusual layer-like pattern in which pure (+)- and pure (–)-layers alternate through the crystal; this arrangement results in a nearly racemic composition although the crystal is ostensibly chiral, space group
P
2
1
2
1
2
1
. Etched crystals of enantiomerically pure hexahelicene display no such pattern. The two kinds of crystal are indistinguishable by x-ray diffraction.
Fossil Molluscan Larvae: A New Biostratigraphic Tool
Authors: Hansen Thor A.
Published: October 2006

Fossil molluscan larvae are less facies dependent and have a wider geographic range than their adult counterparts. They are also easily recovered from cores and small samples. With proper documentation, the study of fossil larvae can considerably enhance the biostratigraphic potential of macrofossils.
Reporting of Faculty Time: An Accounting Perspective
Authors: Thomas Arthur L.
Published: October 2006

Controversial federal regulations requiring universities to report 100 percent of the activities performed by faculty members encounter severe theoretical difficulties of allocation that pervade accounting and that at present are insoluble. Yet it is only natural for universities and government agencies to desire that such allocations be made. Accounting practitioners have faced such reporting dilemmas for generations; their experiences suggest ways of palliating the federal requirements.
Visibility of Comet Nuclei
Authors: Ney Edward P.
Published: October 2006

Photography of the nucleus of comet Halley is the goal of several planned space missions. The nucleus of a comet is surrounded by a cloud of dust particles. If this cloud is optically thick, it will prevent observation of the nuclear surface. Broadband photometry of nine comets has been analyzed to determine the visibility of their nuclei. Only in the case of comet West near perihelion was the dust dense enough to interfere with imaging. Comparison of the visual brightness of the well-observed comets with that of Halley in 1910 leads to the conclusion that the nucleus of Halley can be imaged without significant obscuration by the dust.
Software
Authors: Bacon Glenn
Published: October 2006

Two principal themes are observed in software development, both aimed at improving the productivity of developing and maintaining new applications. The first is to provide increasingly rich system programming function in order to handle the details of managing hardware resources. The second is to provide application development facilities with logical structures and building blocks more closely aligned with the logic of the application itself. An additional challenge is to provide these in a way that will allow continued enhancement of existing software.
Computers in Manufacturing
Authors: Hudson C. A.
Published: October 2006

Computers are now widely used in product design and in automation of selected areas in factories. Within the next decade, the use of computers in the entire spectrum of manufacturing applications, from computer-aided design to computer-aided manufacturing and robotics, is expected to be practical and economically justified. Such widespread use of computers on the factory floor awaits further advances in computer capabilities, the emergence of systems that are adaptive to the workplace, and the development of interfaces to link islands of automation and to allow effective user communications.
Nitrogen Oxide Reactions in the Urban Plume of Boston
Authors: Spicer Chester W.
Published: October 2006

The rate of removal or conversion of nitrogen oxides has been determined from airborne measurements in the urban plume of Boston. The average pseudo-first-order rate constant for removal was 0.18 per hour, with a range of 0.14 to 0.24 per hour under daylight conditions for four study days. The removal process is dominated by chemical conversion to nitric acid and organic nitrates. The removal rate suggests an atmospheric lifetime for nitrogen oxides of about 5 to 6 hours in urban air.
Phytoplankton Division Rates in Light-Limited Environments: Two Adaptations
Authors: Rivkin Richard B. , Voytek Mary A. , Seliger Howard H.
Published: October 2006

Red tide-forming dinoflagellates maximize cell numbers during periods of low light intensities in two ways. For short-term exposures to suboptimal light intensities such as might occur during recirculation in frontal convergences, cell division rates can be maintained at the expense of stored carbon for up to two generation times. During longer periods, corresponding to subsurface transport below a pycnocline, cell division rates eventually decrease as a portion of the fixed carbon is diverted to replenishing stored carbon. As a result, maximum rates of cell division can be resumed rapidly upon advection into surface waters where light intensities are optimal for growth.
Recent Volcanic Activity at Glacier Peak
Authors: Beget James E.
Published: October 2006

Previous reports suggested that Glacier Peak, a volcano in northern Washington State, has been dormant for the past 11,000 years. New radiocarbon dates for volcanic deposits indicate that major volcanic events, such as tephra eruptions, pyroclastic flows, and mudflows traveling tens of kilometers, occurred at least five times in the past 1800 years and nine times in the past 5500 years.
Molecular Characterization of a Functional cDNA Encoding the Rat Substance P Receptor
Authors: Hershey Andrew D. , Krause James E.
Published: October 2006

Substance P is a member of the tachykinin peptide family and participates in the regulation of diverse biological processes. The polymerase chain reaction and conventional library screening were used to isolate a complementary DNA (cDNA) encoding the rat substance P receptor from brain and submandibular gland. By homology analysis, this receptor belongs to the G protein-coupled receptor superfamily. The receptor cDNA was expressed in a mammalian cell line and the ligand binding properties of the encoded receptor were pharmacologically defined by Scatchard analysis and tachykinin peptide displacement as those of a substance P receptor. The distribution of the messenger RNA for this receptor is highest in urinary bladder, submandibular gland, striatum, and spinal cord, which is consistent with the known distribution of substance P receptor binding sites. Thus, this receptor appears to mediate the primary actions of substance P in various brain regions and peripheral tissues.
New Biological Paramagnetic Center: Octahedrally Coordinated Nickel(III) in the Methanogenic Bacteria
Authors: Lancaster Jack R.
Published: October 2006

Methanobacterium bryantii
was grown in medium supplemented with nickel-61, an isotope with a nuclear spin of 3/2. The appearance of nuclear hyperfine structure in the electron paramagnetic resonance spectrum of a cell extract identified a previously observed signal as nickel(III) in an environment of octahedral coordination with rhombic distortions.
Regulation of the Timing of Transposable Element Excision During Maize Development
Authors: Levy Avraham A. , Walbot Virginia
Published: October 2006

The ability of transposable elements (TEs) to insert into or excise out of a genetic locus can be regulated by genetic, environmental, and developmental factors. Tissue- or organ-specific activity of TEs is a frequent and well-characterized example of spatial, developmental regulation. Regulation of the timing of TE activity during ontogeny is less well understood. To analyze timing, TE-induced variegation was quantified in the aleurone of maize kernels, a tissue composed of only a single layer of cells, and sector sizes were assigned to specific cell divisions in aleurone development. Three TE families,
Mu
,
Spm
, and
Ac
/
Ds
, were studied at two genetic loci. It was found that the frequency of transposon excision changes drastically (up to 30-fold increase or equivalent decrease) during the proliferation of the aleurone. Moreover, these changes occur at the same cell divisions in all three TE families. These results suggest that the timing of TE excision during maize development can be controlled by the host.
Efficient Incorporation of Human CD4 Protein into Avian Leukosis Virus Particles
Authors: Young John A. T. , Bates Paul , Willert Karl , Varmus Harold E.
Published: October 2006

Virus envelope (Env) proteins are thought to contain specific signals for selective uptake by virus particles. In the course of attempting to define these signals by testing virus incorporation of CD4-Env chimeric proteins, normal human CD4 was found to be efficiently and selectively assembled into avian leukosis virus particles in quail cells. Viruses bearing CD4 at their surface may be useful reagents in the design of retrovirus-mediated gene therapy for the acquired immune deficiency syndrome.
Surface Science of Heterogeneous Reactions
Authors: White John M.
Published: October 2006

Some of the present and future directions for surface science as a growing and naturally interdisciplinary subject are reviewed. Particular attention is given to surface reaction chemistry as it is related to heterogeneous catalysis, a subject area where there are abundant opportunities for detailed measurements of structure and dynamics at the molecular level.
Social Cost of Tail Loss in
Uta stansburiana
Authors: Fox Stanley F. , Rostker Margaret A.
Published: October 2006

Tail removal from dominant juvenile
Uta stansburiana
resulted in a decrease in social status in dyadic encounters. Most lizards were affected after removal of two-thirds of their tails. In some pairs, dominant lizards lost status after removal of one-third of their tails but regained dominance after the other member of the pair lost two-thirds of its tail. Tail loss in nature may impose a social handicap to successful home range acquisition and thereby increase risk of death.
Nature's Ballistic Missile
Authors: Robb E. Jane , Barron G. L.
Published: October 2006

The parasitic fungus
Haptoglossa mirabilis
infects its rotifer host by means of a gun-shaped attack cell. The anterior end of the cell is elongated to form a barrel; the wall at the mouth is invaginated deep into the cell to form a bore. A walled chamber at the base of the bore houses a complex, missile-like attack apparatus. The projectile is fired from the gun cell at high speed to accomplish initial penetration of the host.
Cloud Droplet Deposition in Subalpine Balsam Fir Forests: Hydrological and Chemical Inputs
Authors: Lovett Gary M. , Reiners William A. , Olson Richard K.
Published: October 2006

Subalpine forests of the northern Appalachians are subject to significant deposition of water and chemicals via cloud droplet impaction. This deposition has been estimated by a method linking micrometeorological measures of turbulent transfer, a detailed representation of canopy structure, and experimentally derived capture efficiencies. Water inputs from clouds are about 46 percent, and chemical inputs range from 150 to 430 percent of the bulk precipitation.
A Cytosolic Protein Catalyzes the Release of GDP from p21

ras
Authors: Wolfman Alan , Macara Ian G.
Published: October 2006

The rate of release of guanine nucleotides from the
ras
proteins (Ras) is extremely slow in the presence of Mg
2+
. It seemed likely, therefore that a factor might exist to accelerate the release of guanosine diphosphate (GDP), and hence the exchange of GDP for guanosine triphosphate (GTP). Such a factor has now been discovered in rat brain cytosol. Brain cytosol was found to catalyze, by orders of magnitude, the release of guanine nucleotides from recombinant v-H-Ras protein bound with [α-
32
P]GDP. This effect occurred even in the presence of a large excess of Mg
2+
, but was destroyed by heat or by incubation of the cytosol for an hour at 37°C in the absence of phosphatase inhibitors. The effect was observed with either v-H-Ras or c-H-Ras, but not with p25

rab3A

, a small G protein with about 30% similarity to Ras. The effect could not be mimicked by addition of recombinant Ras-GAP or purified GEF, a guanine nucleotide exchange factor involved in the regulation of eukaryotic protein synthesis. By gel filtration chromatography, the factor appears to possess a molecular size between 100,000 and 160,000 daltons. This protein (Ras-guanine nucleotide-releasing factor, or Ras-GRF) may be involved in the activation of p21

ras

.
EGF Receptor and
erb
B-2 Tyrosine Kinase Domains Confer Cell Specificity for Mitogenic Signaling
Authors: Di Fiore Pier Paolo , Segatto Oreste , Taylor William G. , Aaronson Stuart A. , Pierce Jacalyn H.
Published: October 2006

The epidermal growth factor (EGF) receptor (EGFR) can efficiently couple with mitogenic signaling pathways when it is transfected into interleukin-3 (IL-3)-dependent 32D hematopoietic cells. When expression vectors for
erb
B-2, which is structurally related to EGFR, or its truncated counterpart, ΔN
erb
B-2, were introduced into 32D cells, neither was capable of inducing proliferation. This was despite overexpression and constitutive tyrosine kinase activity of their products at levels associated with potent transformation of fibroblast target cells. Thus, EGFR and
erb
B-2 couple with distinct mitogenic signaling pathways. The region responsible for the specificity of intracellular signal transduction was localized to a 270-amino acid stretch encompassing their respective tyrosine kinase domains. Thus, tissue- or cell-specific regulation of growth factor receptor signaling can occur at a point after the initial interaction of growth factor with receptor. Such specificity in signal transduction may account for the selection of certain oncogenes in some malignancies.
Genetic Suppression of Mutations in the
Drosophila abl
Proto-Oncogene Homolog
Authors: Gertler Frank B. , Doctor John S. , Hoffmann F. Michael
Published: October 2006

The
Drosophila abelson
(
abl
) gene encodes the homolog of the mammalian
c-abl
cytoplasmic tyrosine kinase and is an essential gene for the development of viable adult flies. Three second-site mutations that suppress the lethality caused by the absence of
abl
function have been isolated, and all three map to the gene
enabled
(
ena
). The mutations are recessive embryonic lethal mutations but act as dominant mutations to compensate for the neural defects of
abl
mutants. Thus, mutations in a specific gene can compensate for the absence of a tyrosine kinase.
Rare and Endangered Species of Plants—The Soviet Side
Authors: Elias Thomas S.
Published: October 2006

In late 1972, the Soviet Union embarked on a program to identify and document plant species that are threatened with extinction. Perhaps 2000 species in the Soviet Union are in need of monitoring or protective measures, while nearly 200 may be in immediate danger of extinction. Currently, the Soviet Union has an official, national list of endangered species, and each of the 15 republics has prepared a regional list. Once a revised national list is prepared, Soviet scientists hope that the Supreme Soviet will pass a law protecting those species. A corresponding law for endangered animals was passed in 1980.
Detection of a Compact Radio Source near the Center of a Gravitational Lens: Quasar Image or Galactic Core?
Authors: Gorenstein M. V. , Shapiro I. I. , Cohen N. L. , Corey B. E. , Falco E. E. , Marcaide J. M. , Rogers A. E. E. , Whitney A. R. , Porcas R. W. , Preston R. A. , Rius A.
Published: October 2006

By use of a new, very sensitive interferometric system, a faint, compact radio source has been detected near the center of the galaxy that acts as the main part of a gravitational lens. This lens forms two previously discovered images of the quasar Q09S7 + 561, which lies in the direction of the constellation Ursa Major. The newly detected source has a core smaller than 0.002 arc second in diameter with a flux density of 0.6 ± 0.1 millijansky at the 13-centimeter wavelength of the radio observations. This source could be the predicted third image of the transparent gravitational lens, the central core of the galaxy, or some combination of the two. It is not yet possible to choose reliably between these alternatives.
Academic Freedom and the Classified Information System
Authors: Rosenbaum Robert A. , Tenzer Morton J. , Unger Stephen H. , Van Alstyne William , Knight Jonathan
Published: October 2006

Executive Order 12356, signed by President Reagan on 2 April 1982, prescribes a system for classifying information on the basis of national security concerns. The order gives unprecedented authority to government officials to intrude at will in controlling academic research that depends on federal support. As such, it poses a serious threat to academic freedom and hence to scientific advances and the national security.
Mariner Mark II and the Exploration of the Solar System
Authors: Neugebauer Marcia
Published: October 2006

Mariner Mark II is a concept for the next generation of deep-space missions. The project would provide limited, focused sets of Voyager- and Galileo-quality planetary observations at a fraction of the cost of the Voyager and Galileo projects. This article discusses Mariner Mark II's cost goals, scientific objectives, and mission requirements. Strategies for limiting costs include the use of a reconfigurable spacecraft, a multimission ground-support system, and selected new technologies.
Genetic Transfer in Plants Through Interspecific Protoplast Fusion
Authors: Shepard James F. , Bidney Dennis , Barsby Tina , Kemble Roger
Published: October 2006

Protoplasts of sexually incompatible species have been fused and in some combinations have given rise to somatic hybrid plants. Partial elimination of parental chromosomes from either species is common in such hybrids, but total chromosome loss has generally occurred only with phylogenetically unrelated pairings. Genetic function of one parent may be retained despite a complete loss of its chromosomes, suggesting that genetic introgression is possible in the absence of complete donor chromosomes. A model interspecific combination for such studies is the potato-tomato somatic hybrid for which numerous phenotypes and karyotypes are encountered at the outset, with a broader range observed in the second somatic generation.
Micronesian Prehistory: An Archeological Overview
Authors: Craib John L.
Published: October 2006

The majority of archeological work in Micronesia has occurred in the last 5 years. Prehistoric peoples moved into this area from two separate areas—insular southeast Asia and eastern Melanesia. The high islands of western Micronesia were settled at least 4000 years ago. Settlement in eastern Micronesia occurred at least 2000 years ago. On high islands, complex, stratified societies developed, each with distinctive material remains. Atolls have proved to be significant sources of archeological materials and figure prominently in the prehistory of the area.
Genetic Linkage of C3H/HeJ and BALB/c Endogenous Ecotropic C-Type Viruses to Phosphoglucomutase-1 on Chromosome 5
Authors: Ihle James N. , Joseph David R. , Domotor Joseph J.
Published: October 2006

The genetic linkage of the endogenous C3H/HeJ C-type ecotropic virus to phosphoglucomutase-1 (0.28, recombinant fraction) on chromosome 5 was established by means of serological assays of backcrossed mice. With a combination of serological techniques and DNA-DNA hybridization the BALB/c endogenous ecotropic virus was shown to be either closely linked or allelic with the C3H/HeJ locus.
Mycoplasma-Like Organisms: Occurrence with the Larvae and Adults of a Marine Bryozoan
Authors: Zimmer Russel L. , Woollacott Robert M.
Published: October 2006

Larvae and adults of the marine bryozoan
Watersipora cucullata
invariably possess numerous extracellular mycoplasma-like organisms. Mesodermally encapsulated groups of these atypical bacteria occur in the visceral coeloms of all colony members. In contrast, thousands of the symbionts are externally attached to each larva along a unique superficial groove; the microorganisms are internalized during the complex metamorphosis, thus inoculating the incipient colony. The consequences to the bryozoan of this association are not known.
Desuppression of Leaf Primordia of
Plagiochila arctica
(Hepaticae) by Ethylene Antagonists
Authors: Basile D. V. , Basile M. R.
Published: October 2006

Silver nitrate, α-aminooxyacetic acid, and aminoethoxyvinylglycine, three potent inhibitors of ethylene synthesis and action, induced the same kind of phenovariation in the liverwort
Plagiochila arctica
Bryhn and Kaal (Hepaticae) as do antagonists of the synthesis of hydroxyproline-containing protein. This finding (i) supports the hypothesis that hydroxyproline-protein has a role in ethylene-mediated suppression, (ii) provides evidence that the role of ethylene in the correlative development of leafy liverwort gametophytes may be similar to its role in flowering plants, and (iii) contributes to the characterization of a morphoregulatory system that mediates cellular suppression in leafy liverworts and possibly all land plants.
Basal Localization of the Presumptive Auxin Transport Carrier in Pea Stem Cells
Authors: Jacobs Mark , Gilbert Scott F.
Published: October 2006

By means of an indirect immunofluorescence technique with the use of monoclonal antibodies, the location of the presumptive auxin transport carrier of pea stem tissue was identified in the plasma membranes at the basal ends of parenchyma cells sheathing the vascular bundles. The results represent what is believed to be the first direct evidence for the hypothesized basal efflux carrier conferring polarity to auxin transport in plant stems.
Tracking the Flow of Information
Authors: Pool Ithiel de Sola
Published: October 2006

By using words transmitted and words attended to as common denominators, novel indexes were constructed of growth trends in 17 major communications media from 1960 to 1977. There have been extraordinary rates of growth in the transmission of electronic communications, but much lower rates of growth in the material that people actually consume, representing the phenomenon often labeled information overload. Growth in print media has sharply decelerated, and a close relationship is found between the cheapness of a medium and its rate of growth.
Territorial Bell Miners and Other Birds Affecting Populations of Insect Prey
Authors: Loyn Richard H. , Runnalls Ross G. , Forward Gail Y. , Tyers Jeanie
Published: October 2006

Bell miners (
Manorina melanophrys
) feed primarily on the lerps and nymphs of psyllids, and they defend communal territories against other bird species. As bell miners were removed experimentally from a psyllid-infested patch of eucalypt forest, birds of 11 other species moved in to feed on psyllids and within 4 months they eradicated the infestation. This shows the ability of other birds to control these insects in the absence of bell miners and the value of interspecific territoriality to bell miners.
A Magnesium Current in
Paramecium
Authors: Preston Robin R.
Published: October 2006

Recent reappraisals of the role of ionized magnesium in cell function suggest that many cells maintain intracellular free Mg
2+
at low concentrations (0.1 to 0.7 mM) and that external agents can influence cell function via changes in intracellular Mg
2+
concentration. Depolarization and hyperpolarization of voltage-clamped
Paramecium
elicited a Mg
2+
-specific current,
I
Mg
. Both Co
2+
and Mn
2+
were able to substitute for Mg
2+
as charge carriers, but the resultant currents were reduced compared with Mg
2+
currents. Intracellular free Mg
2+
concentrations were estimated from the reversal potential of
I
Mg
to be about 0.39 mM. The
I
Mg
was inhibited when external Ca
2+
was removed or a Ca
2+
chelator was injected, suggesting that its activation was Ca
2+
-dependent.
The Drug Dilemma: Manipulating the Demand
Authors: Jarvik Murray E.
Published: October 2006

Drug abuse in the United States has posed a dilemma during most of this century. Intemperate use of reinforcing drugs is hazardous to health and safety, but strict prohibition fosters an illicit market with criminal effects that may be equally harmful. The crux of the problem is the willingness of millions of people to risk toxicity and arrest to gain psychopharmacological rewards. Cocaine is the present source of most concern. Recommendations for reducing demand and abuse are given, including the implementation of preventive techniques, the investigation of various treatments, the use of modern chemical and electronic technology, and the development of new pharmacological alternatives.
Norepinephrine Inhibits Calcium-Dependent Potentials in Rat Sympathetic Neurons
Authors: Horn John P. , McAfee Donald A.
Published: October 2006

Norepinephrine reversibly antagonizes three calcium-dependent potentials recorded from rat postganglionic neurons. Norepinephrine inhibits the development of a shoulder on the action potential, the magnitude of the hyperpolarizing afterpotential, and the rate of rise and amplitude of the calcium spike. The action of norepinephrine is antagonized by the α-adrenergic antagonist phentolamine, but not by MJ 1999, a β-adrenergic antagonist. These results suggest that activation of an α-adrenergic receptor may antagonize a voltage-sensitive calcium current.
Angiotensin Convertase Activities in Human Alveolar Macrophages: Effects of Cigarette Smoking and Sarcoidosis
Authors: Hinman Lois M. , Stevens Cynthia , Matthay Richard A. , Gee J. Bernard L.
Published: October 2006

Angiotensin I convertase activity has been found in human alveolar macrophages from normal volunteers and patients with pulmonary sarcoidosis. This activity is higher in the alveolar macrophages from smokers than from nonsmokers, and is even more elevated in sarcoid patients. The activity can be detected with both angiotensin I and bradykinin analogs and appears to require protein synthesis, but the enzyme is not secreted by alveolar macrophages in culture.
The Desertron: Colliding Beams at 20 TeV
Authors: Diebold R.
Published: October 2006

With today's technology, the center-of-mass energy of proton-proton and proton-antiproton collisions can be extended by an order of magnitude beyond that achievable with machines presently in operation or under construction. Such a facility would open a vast new energy region which has been suggested theoretically to contain new kinds of particles and interactions. Several accelerator options, their rate capabilities, and their costs are described.
Coal in the United States: A Status Report
Authors: Perry Harry
Published: October 2006

Historical trends in U.S. coal production, transportation, and utilization and their causes are analyzed. The changing structure of the coal industry and its possible future direction, as it is driven by the effects of the oil embargo and world oil prices, are examined. National policies in the United States to increase coal use from indigenous sources in order to diversify and increase reliability of supply raise questions as to availability of coal supply and potential markets. Possible constraints on U.S. coal production, transportation, and utilization are appraised, and it is concluded that increased coal consumption is "demand constrained." The causes and potential means of removal of these limitations are examined.
Barium Isotopes in Allende Meteorite: Evidence Against an Extinct Superheavy Element
Authors: Lewis R. S. , Anders E. , Shimamura T. , Lugmair G. W.
Published: October 2006

Carbon and chromite fractions from the Allende meteorite that contain isotopically anomalous xenon-131 to xenon-136 (carbonaceous chondrite fission or CCF xenon) at up to 5 x 10
11
atoms per gram show no detectable isotopic anomalies in barium-130 to barium-138. This rules out the possibility that the CCF xenon was formed by in situ fission of an extinct superheavy element. Apparently the CCF xenon and its carbonaceous carrier are relics from stellar nucleosynthesis.
Plutonium Speciation in Water from Mono Lake, California
Authors: Cleveland Jess M. , Rees Terry F. , Nash Kenneth L.
Published: October 2006

The solubility of plutonium in Mono Lake water is enhanced by the presence of large concentrations of indigenous carbonate ions and moderate concentrations of fluoride ions. In spite of the complex chemical composition of this water, only a few ions govern the behavior of plutonium, as demonstrated by the fact that it was possible to duplicate plutonium speciation in a synthetic water containing only the principal components of Mono Lake water.