bluuebunny/crossref_metadata_2025 huggingface dataset:
Guanosine 3′,5′-Monophosphate in Sympathetic Ganglia: Increase Associated with Synaptic Transmission
Authors: Weight Forrest F. , Petzold Gary , Greengard Paul
Published: October 2006

Brief stimulation of cholinergic preganglionic nerve fibers resulted in an increase in guanosine 3′,5′-monophosphate (cyclic GMP) in the bullfrog sympathetic ganglion. When the release of synaptic transmitter was prevented by a high-magnesium, low-calcium Ringer solution, stimulation of preganglionic nerve fibers did not increase cyclic GMP in the ganglion. The increase in cyclic GMP caused by preganglionic stimulation was also blocked by the muscarinic antagonist, atropine. The data indicate that the increase in cyclic GMP is associated with synaptic transmission and support the possibility that cyclic GMP may mediate the postsynaptic action of acetylcholine at muscarinic cholinergic synapses.
Chan Chan: Andean Alternative of the Preindustrial City
Authors: Moseley Michael E.
Published: October 2006

I have discussed Chan Chan in terms of its political and economic characteristics because state organization had a pervasive impact on the growth and structure of the settlement. In this sense the capital of Chimor resembles Cuzco the Inca capital. Both metropolitan centers served as seats of Andean empires governed by noble classes headed by members of royal dynasties. Each state relied on a system of labor taxation and controlled the production, collection, and redistribution of goods. These political and economic institutions gave the sites distinctive but parallel forms. First, the settlements were large, containing a great deal of monumental architecture, but size and construction do not reflect substantial populations because building was done by nonresident work forces. Second, the urban proletariat were relatively few in numbers and composed of retainers or service personnel at Cuzco, as well as craftsmen and artisans at Chan Chan. Third, civic facilities were intended to serve the aristocracy and the state, not the common citizenry because these were governmental, not folk or popular, centers. And, fourth, palaces tied up a great amount of urban space because each monarch built his own seat of government during life and this became a monument to his name after death.

In conclusion, I cannot say Chan Chan and Cuzco are necessarily typical of other prehistoric population centers in the region because these centers are little studied. I can, however, say Chan Chan was distinct from the preindustrial cities of Europe and Mesopotamia, but this is not surprising because the capital of Chimor was the product of distinctly Andean cultural institutions.
Pest Management
Authors: Giese Ronald L. , Peart Robert M. , Huber Roger T.
Published: October 2006

Although it has not yet been universally adopted, pest management figures prominently in current planning. For pest management to be effective, agricultural scientists must adopt an interdisciplinary approach to solving problems; this means considering not only complexes of pests including insects, pathogens, and weeds, but whole crop systems. The requisites for successful pest management programs include availability of current weather data, cooperation between research and Extension personnel, and feedback from individual growers.

A pilot program for alfalfa pest control is in its third year of development at Purdue University. It involves the cooperation of entomologists, engineers, physiologists, economists, and agronomists, and research and implementation proceed simultaneously. Microcomputers are used for monitoring, integrating, storing, and transmitting meteorological information to a central location, where it is used in simulations of the alfalfa plant and the alfalfa weevil. The resulting advisories are produced at teletype terminals at four locations in the alfalfa growing region of Indiana. Our experience with this prototype system indicates that computer-based pest management programs will be dynamic and reliable systems capable of delivering alternative action strategies with virtually unlimited accessibility.
Specificity for Aminoacylation of an RNA Helix: an Unpaired, Exocyclic Amino Group in the Minor Groove
Authors: Musier-Forsyth Karin , Usman Nassim , Scaringe Stephen , Doudna Jennifer , Green Rachel , Schimmel Paul
Published: October 2006

An acceptor stem G3⋅U70 base pair is a major determinant of the identity of an alanine transfer RNA. Hairpin helices and RNA duplexes consisting of complementary single strands are aminoacylated with alanine if they contain G3⋅U70. Chemical synthesis of RNA duplexes enabled the introduction of base analogs that tested the role of specific functional groups in the major and minor grooves of the RNA helix. The results of these experiments indicate that an unpaired guanine 2-amino group at a specific position in the minor groove of an RNA helix marks a molecule for aminoacylation with alanine.
Adaptation of Photosynthetic Processes to Stress
Authors: Berry Joseph A.
Published: October 2006

I have focused on examples of plant adaptations to environmental conditions that range from adjustments in the allocation of metabolic resources and modification of structural components to entirely separate mechanisms. The result of these modifications is more efficient performance under the stresses typically encountered in the plants' native habitats. Such adaptations, for reasons which are not entirely clear, often lead to poorer performance in other environmental conditions. This situation may be a fundamental basis for the tendency toward specialization among plants native to specific niches or habitats. The evolutionary mechanisms that have resulted in these specializations are very large-scale processes. It seems reasonable to suppose that the plants native to particular habitats are relatively efficient in terms of the limitations imposed by those habitats, and that the adaptive mechanisms these plants possess are, compared to those which have evolved in competing organisms, the most successful biological means of coping with the environmental stresses encountered.

I believe that we can learn from nature and utilize the adaptive mechanisms of these plants in agriculture to replace in part our present reliance on resources and energy to modify the environment for plant growth. By analogy with natural systems, improved resource utilization will require specialization and greater knowledge of the limitations of a particular environment and plant genotype. For example, the cultural conditions, plant architecture, and physiological responses necessary to achieve high water use efficiency from our crop species with C
4
photosynthesis probably differ from those required to achieve maximum total growth. Also, efforts to control water application to eliminate waste carry with them the risk that the crop could be injured by inadequate water. Thus, greater demands would be placed on the crop physiologist, the plant breeder, and the farmer. Planting and appropriate management of adapted crop genotypes could enable cultivation of many areas presently considered unusable because of environmental extremes or shortage of resources, and may lead to more efficient resource utilization on land already under cultivation. The costs or benefits of this cannot yet be estimated. However, I suspect that the greatest potential for application of such techniques will be in the developing rather than the developed regions of the world.

The genetic and functional diversity of plants is a tremendous biological resource. The capacity of plants to adjust in the future to changing environmental conditions depends on this diversity and on evolutionary processes of nature. Wild plants may provide a source of genetic material to improve crop plants. Also, as advocated by McKell, wild plants can be utilized to a greater extent directly by man. Long-term research efforts and commitment to preserve natural habitats and their populations of wild plants will be required to maintain and more effectively utilize this resource.
Magma Beneath Yellowstone National Park
Authors: Eaton Gordon P. , Christiansen Robert L. , Iyer H. M. , Pitt Andrew D. , Mabey Don R. , Blank H. Richard , Zietz Isidore , Gettings Mark E.
Published: October 2006

The Yellowstone plateau volcanic field is less than 2 million years old, lies in a region of intense tectonic and hydrothermal activity, and probably has the potential for further volcanic activity. The youngest of three volcanic cycles in the field climaxed 600,000 years ago with a voluminous ashflow eruption and the collapse of two contiguous cauldron blocks. Doming 150,000 years ago, followed by voluminous rhyolitic extrusions as recently as 70,000 years ago, and high convective heat flow at present indicate that the latest phase of volcanism may represent a new magmatic insurgence. These observations, coupled with (i) localized postglacial arcuate faulting beyond the northeast margin of the Yellowstone caldera, (ii) a major gravity low with steep bounding gradients and an amplitude regionally atypical for the elevation of the plateau, (iii) an aeromagnetic low reflecting extensive hydrothermal alteration and possibly indicating the presence of shallow material above its Curie temperature, (iv) only minor shallow seismicity within the caldera (in contrast to a high level of activity in some areas immediately outside), (v) attenuation and change of character of seismic waves crossing the caldera area, and (vi) a strong azimuthal pattern of teleseismic P-wave delays, strongly suggest that a body composed at least partly of magma underlies the region of the rhyolite plateau, including the Tertiary volcanics immediately to its northeast.

The Yellowstone field represents the active end of a system of similar volcanic foci that has migrated progressively northeastward for 15 million years along the trace of the eastern Snake River Plain. Regional aeromagnetic patterns suggest that this course was guided by the structure of the Precambrian basement. If, as suggested by several investigators, the Yellowstone magma body marks a contemporary deep mantle plume, this plume, in its motion relative to the North American plate, would appear to be "navigating" along a fundamental structure in the relatively shallow and brittle lithosphere overhead. The concept that a northeastward-propagating major crustal fracture controls the migration path of the major foci of volcanisim is at least equally favored by existing data, as Smith
et al.
noted.
Floating Glacial Ice Caps in the Arctic Ocean
Authors: Broecker Wallace S.
Published: October 2006

Two arguments are presented, one in favor of the existence of thicker ice in the Arctic Ocean during glacial time, and the other in favor of a full-fledged Arctic ice cap. The first is based on the Greenland air temperature record obtained from isotopic studies of the Camp Century ice core. The second is based on the oxygen isotope record of benthic foraminifera from a deep Pacific Ocean core.
Intercalation of Metallocenes in the Layered Transition-Metal Dichalcogenides
Authors: Dines Martin B.
Published: October 2006

Novel intercalation complexes of many of the layered transition-metal dichalcogenides incorporating the metallocenes of cobalt and chromium have been prepared. Evidence is presented indicating a configuration in which the five-membered rings of the metallocene guest are situated perpendicular to the slabs of the dichalcogenide host. In the complexes the metallocenes apparently behave as pseudo-alkali metals, transferring an electron to the chalcogenide.
Medium Effects in Antibody-Catalyzed Reactions
Authors: Lewis Cristina , Krämer Thomas , Robinson Suzanne , Hilvert Donald
Published: October 2006

Catalytic antibody technology has been used to explore the contribution of medium effects to the overall rate of an enzyme-catalyzed reaction. An antibody generated against a derivative of 2-acetamido-1,5-napthalenedisulfonate efficiently catalyzes the decarboxylation of 5-nitro-3-carboxybenzisoxazole. This unimolecular reaction is not susceptible to general acid-base catalysis but is highly sensitive to microenvironment; thus, it provides a simple chemical model for biologically important decarboxylations. The 10
4
-fold rate acceleration observed for the antibody reflects the kinetic advantage of the low-dielectric environment of the binding pocket acting to destabilize the substrate by desolvation and to stabilize the charge-delocalized transition state through dispersion interactions. These results are pertinent to an understanding of solvent effects in enzymic reactions in general and suggest approaches for developing antibody catalysts for numerous other reactions that involve large changes in charge distribution as the reaction coordinate is traversed.
New Technique for Decorating Dislocations in Olivine
Authors: Kohlstedt D. L. , Goetze C. , Durham W. B. , Vander Sande J.
Published: October 2006

Oxidation of iron-rich olivine induced in the laboratory causes preferential precipitation on lattice dislocations. This simple dislocation decoration technique greatly reduces the cost and time involved in surveying the dislocation structures of deformed olivine crystals and opens the way to a more thorough understanding of the deformation of this important geologic material.
Sesquiterpene Antitumor Agents: Inhibitors of Cellular Metabolism
Authors: Lee Kuo-Hsiung , Hall Iris H. , Mar Eng-Chun , Starnes Charles O. , ElGebaly Salwa A. , Waddell Thomas G. , Hadgraft Robert I. , Ruffner Charles G. , Weidner Ivonne
Published: October 2006

Helenalin and tenulin injected into CF1 male mice bearing Ehrlich ascites tumors inhibit DNA synthesis and DNA polymerase enzymatic activity in the tumor cells. Helenalin inhibited protein synthesis. Both drugs increased the concentration of adenosine 3′,5′-monophosphate, and interfered with glycolytic and mitochondrial energy processes. Cholesterol synthesis was also inhibited, resulting in lower serum cholesterol levels in tumor-bearing animals. Data obtained in vitro indicate that the cyclopentenone-bearing sesquiterpene lactone and related compounds do not alkylate purine bases of nucleic acids but rather undergo a Michael-type addition reaction with the sulfhydryl groups of reduced glutathione and L-cysteine. Thus, the inhibition of cellular enzyme activities and metabolism that has been observed with these drugs might be explained by the occurrence of a Michael-type reaction.
A 32-kD GTP-Binding Protein Associated with the CD4-p56
lck
and CD8-p56
lck
T Cell Receptor Complexes
Authors: Telfer Janice C. , Rudd Christopher E.
Published: October 2006

The guanosine triphosphate (GTP)-binding proteins include signal-transducing heterotrimeric G proteins (for example, G
s
, G
i
), smaller GTP-binding proteins that function in protein sorting, and the oncogenic protein p21
ras
. The T cell receptor complexes CD4-p56
lck
and CD8-p56
lck
were found to include a 32- to 33-kilodalton phosphoprotein (p32) that was recognized by an antiserum to a consensus GTP-binding region in G proteins. Immunoprecipitated CD4 and CD8 complexes bound GTP and hydrolyzed it to guanosine diphosphate (GDP). The p32 protein was covalently linked to [α-
32
P]GTP by ultraviolet photoaffinity labeling. These results demonstrate an interaction between T cell receptor complexes and an intracellular GTP-binding protein.
Magnetic Direction Finding: Evidence for Its Use in Migratory Indigo Buntings
Authors: Emlen Stephen T. , Wiltschko Wolfgang , Demong Natalie J. , Wiltschko Roswitha , Bergman Simon
Published: October 2006

The orientational capabilities of caged migratory indigo buntings were studied under differing magnetic field conditions. When tested in a situation allowing minimal exposure to visual cues but in the presence of the normal geomagnetic field, the birds demonstrated a significant orientation in the appropriate migratory direction (to the north). When the horizontal component of the magnetic field was deflected clockwise 120° by activation of Helmholtz coils surrounding the cage, the orientation of the buntings shifted accordingly (clockwise to geographic east-southeast). These results suggest that indigo buntings are not only able to detect the geomagnetic field, but also can use this information in the finalization of their migratory direction.
Appearance of Vegetation in Ultraviolet Light: Absorbing Flowers, Reflecting Backgrounds
Authors: Frohlich Michael W.
Published: October 2006

Flowers that uniformly absorb ultraviolet light may contrast strikingly with a bright ultraviolet-reflecting background, such as densely hairy or glaucous foliage, white soils, or the sky. Shadows will not resemble these flowers if the appearance of each in visible light is also considered. Examples are shown from Mexican heliotropiums and Michigan dune plants.
Mars Dynamics, Atmospheric and Surface Properties: Determination from Viking Tracking Data
Authors: Michael W. H. , Mayo A. P. , Blackshear W. T. , Tolson R. H. , Kelly G. M. , Brenkle J. P. , Cain D. L. , Fjeldbo G. , Sweetnam D. N. , Goldstein R. B. , MacNeil P. E. , Reasenberg R. D. , Shapiro I. I. , Boak T. I. S. , Grossi M. D. , Tang C. H.
Published: October 2006

Approximately 3 months of radio tracking data from the Viking landers have been analyzed to determine the lander locations, the orientation of the spin axis of Mars, and a first estimate from Viking data of the planet's spin rate. Preliminary results have also been obtained for atmospheric parameters and radii at occultation points and for properties of the surface in the vicinity of lander 1.
Symbiont Recognition and Subsequent Morphogenesis as Early Events in an Animal-Bacterial Mutualism
Authors: McFall-Ngai Margaret J. , Ruby Edward G.
Published: October 2006

Bacterial colonization of the developing light organ of the squid
Euprymna scolopes
is shown to be highly specific, with the establishment of a successful association resulting only when the juvenile host is exposed to seawater containing one of a subset of
Vibrio fischeri
strains. Before a symbiotic infection the organ has elaborate epithelial structures covered with cilia and microvilli that are involved in the transfer of bacteria to the incipient symbiotic tissue. These structures regressed within days following infection; however, they were retained in uninfected animals, suggesting that the initiation of symbiosis influences, and is perhaps a prerequisite for, the normal developmental program of the juvenile host.
Selective Cleavage of Human DNA: RecA-Assisted Restriction Endonuclease (RARE) Cleavage
Authors: Ferrin Lance J. , Camerini-Otero R. Daniel
Published: October 2006

Current methods for sequence-specific cleavage of large segments of DNA are severely limited because of the paucity of possible cleavage sites. A method is described whereby any Eco RI site can be targeted for specific cleavage. The technique is based on the ability of RecA protein from
Escherichia coli
to pair an oligonucleotide to its homologous sequence in duplex DNA and to form a three-stranded complex. This complex is protected from Eco RI methylase; after methylation and RecA protein removal, Eco RI restriction enzyme cleavage was limited to the site previously protected from methylation. When pairs of oligonucleotides are used, a specific fragment can be cleaved out of genomes. The method was tested on λ phage,
Escherichia coli
, and human DNA. Fragments exceeding 500 kilobases in length and yields exceeding 80 percent could be obtained.
The Influence of Allogeneic Cells on the Human T and B Cell Repertoire
Authors: van Rood Jon J. , Claas Frans H. J.
Published: October 2006

Clinical transplantation is often complicated by rejection episodes, in which the immune system of the recipient reacts to the foreign transplantation (HLA) antigens on the graft. This immune response includes humoral and cellular components. In the first, B lymphocytes form antibodies to the HLA alloantigens. In the second, CD8
+
T lymphocytes recognize and react to HLA class I antigens, and CD4
+
T cells react to HLA class II antigens. The frequency and severity of these rejection episodes can be diminished by immunosuppressive drugs, HLA matching between donor and recipient, and immune modulation by blood transfusion. Effective HLA matching between donor and recipient is not always possible and often not necessary. Insight into the factors that influence the T and B cell repertoire after blood transfusion might lead to new approaches to improve graft survival.
Real-Time, Very-Long-Baseline Interferometry Based on the Use of a Communications Satellite
Authors: Yen J. L. , Kellermann K. I. , Rayhrer Benno , Broten N. W. , Fort D. N. , Knowles S. H. , Waltman W. B. , Swenson G. W.
Published: October 2006

The Hermes satellite, a joint Canadian-American program, has been used to provide a communication channel between radio telescopes in West Virginia and Ontario, for very-long-baseline interferometry (VLBI). This system makes possible instantaneous correlation of the data as well as a sensitivity substantially better than that of earlier VLBI systems, by virtue of a broader observational bandwidth. With the use of a geostationary communications satellite it is possible to eliminate the tape recorders and the most troublesome part of the postobservational data processing. A further possibility is the development of a phase-coherent interferometer.
Paleodemography of the Libben Site, Ottawa County, Ohio
Authors: Lovejoy C. Owen , Meindl Richard S. , Pryzbeck Thomas R. , Barton Thomas S. , Heiple Kingsbury G. , Kotting David
Published: October 2006

The Libben site, a Late Woodland ossuary and occupation site from the Great Black Swamp of northern Ohio has yielded a well-preserved skeletal sample of 1327 articulated individuals. The outstanding preservation and completeness of the site and the utilization of an exhaustive aging methodology make this the largest and most comprehensively censused North American prehistoric cemetery. Survivorship data indicate a robust, successful population. Life expectancy at birth was 20 years. Among adults, male mortality was consistently higher than female, a condition possibly related to high interpersonal and intergroup aggression. Infant mortality was generally low, and a general hypothesis concerning the elevation of infant mortality and the simultaneous depression of adult mortality among aboriginal peoples after European contact is suggested.
Melatonin Content of the Human Pineal Gland
Authors: Greiner A. C. , Chan S. C.
Published: October 2006

Gas chromatography with electron capture detection was used to quantitate melatonin in single human pineal glands. The sensitivity of this melatonin assay is in the low picogram range. A 24-hour rhythm of pineal melatonin content was observed.
Transducin Activation by Rhodopsin Without a Covalent Bond to the 11-
Cis
-Retinal Chromophore
Authors: Zhukovsky Eugene A. , Robinson Phyllis R. , Oprian Daniel D.
Published: October 2006

Rhodopsin and the visual pigments are a distinct group within the family of G-protein-linked receptors in that they have a covalently bound ligand, the 11-
cis
-retinal chromophore, whereas all of the other receptors bind their agonists through noncovalent interactions. The retinal chromophore in rhodopsin is bound by means of a protonated Schiff base linkage to the ε-amino group of Lys-296. Two rhodopsin mutants have been constructed, K296G and K296A, in which the covalent linkage to the chromophore is removed. Both mutants form a pigment with an absorption spectrum close to that of the wild type when reconstituted with the Schiff base of an
n
-alkylamine and 11-
cis
-retinal. In addition, the pigment formed from K296G and the
n
-propylamine Schiff base of 11-
cis
-retinal was found to activate transducin in a light-dependent manner, with 30 to 40% of the specific activity measured for the wild-type protein. It appears that the covalent bond is not essential for binding of the chromophore or for catalytic activation of transducin.
Carbon-14 Time Scale Extended: Comparison of Chronologies
Authors: Grootes P. M.
Published: October 2006

Thermal diffusion isotopic enrichment of carbon-14 has extended the radiocarbon dating range to about 75,000 years ago. Twenty-eight samples obtained up to June 1976, mainly from northwest Europe, were dated. Consideration of the basic assumptions of carbon-14 dating and of the sources of contamination indicates that the ages are generally reliable. Together with the pollen analytic and stratigraphic evidence, the dates yield a more detailed radiocarbon time scale for climatic variations in northwest Europe, showing three early glacial interstades. The radiocarbon time scale agrees with the Camp Century chronology and with the thorium-230 ages of corals representing high sea level stands on New Guinea. There is a discrepancy between the radiocarbon time scale and the deep-sea chronology, which may be due to correlation errors. With a modified interpretation of the correlation, all four time scales agree within the estimated experimental uncertainties of the dating techniques used.
Mineralization Kinetics: A Constant Composition Approach
Authors: Tomson M. B. , Nancollas G. H.
Published: October 2006

A new method is described for studying, reproducibly, the kinetics of crystallization of minerals under conditions of constant solution composition even at very low supersaturations. For calcium phosphates the method provides direct evidence for octacalcium phosphate as the precursor to hydroxyapatite precipitation at physiological
p
H.
Calcareous Deposits in the Renal Sac of a Molgulid Tunicate
Authors: Saffo Mary Beth , Lowenstam Heinz A.
Published: October 2006

Weddellite (calcium oxalate dihydrate) and calcite (anhydrous calcium carbonate phase) are components of concretions in the renal sac of the ascidian tunicate
Molgula manhattensis
. The presence of weddellite along with urate in the concretions suggests a resemblance to human kidney stones, although, unlike the latter, the concretions in
Molgula
do not seem to be pathologic deposits.
Evidence of Paleozoic Chromosomes from Lycopod Microgametophytes
Authors: Brack-Hanes Sheila D. , Vaughn Jack C.
Published: October 2006

A Pennsylvanian arborescent lycopod cone,
Lepidostrobus schopfii
, has microspores that have been found to have intracellular features that are interpreted as nuclei and mitotic chromosomes. The cellularized gametophytes conform to the early stages of growth that occur in modern
Selaginella
microgametophytes. Since the megagametophyte of
L. schopfii
is similar in development to extant species of
Isoetes
, the fossil now is known to have portions of its life cycle in common with both
Selaginella
and
Isoetes
.
Charge Separation in a Reaction Center Incorporating Bacteriochlorophyll for Photoactive Bacteriopheophytin
Authors: Kirmaier Christine , Gaul Dale , DeBey Randy , Holten Dewey , Schenck Craig C.
Published: October 2006

Site-directed mutagenic replacement of M subunit Leu
214
by His in the photosynthetic reaction center (RC) from
Rhodobacter sphaeroides
results in incorporation of a bacteriochlorophyll molecule (BChl) in place of the native bacteriopheophytin (BPh) electron acceptor. Evidence supporting this conclusion includes the ground-state absorption spectrum of the (M)L214H mutant, pigment and metal analyses, and time-resolved optical experiments. The genetically modified RC supports transmembrane charge separation from the photoexcited BChl dimer to the primary quinone through the new BChl molecule, but with a reduced quantum yield of 60 percent (compared to 100 percent in wild-type RCs). These results have important implications for the mechanism of charge separation in the RC, and rationalize the choice of (bacterio)pheophytins as electron acceptors in a variety of photosynthetic systems.
The Mystery of the Shroud of Turin Challenges 20th-Century Science
Authors: Culliton Barbara J.
Published: October 2006

On the face of it, the very idea that the linen cloth in which Jesus Christ was wrapped in the tomb should have survived to this day would seem incredible. It demands even more of human credulity that the cloth bears a photographic likeness which would seem to be that of Jesus as he lay in the tomb. [From
The Shroud of Turin
by IAN WILSON]
Cyclic Change in Late Triassic Lacustrine Communities
Authors: Olsen Paul E. , Remington Charles L. , Cornet Bruce , Thomson Keith S.
Published: October 2006

A new type of lake and shore assemblage has been found in the Late Triassic age rocks of North Carolina and Virginia (Dan River group). It includes abundant aquatic reptiles, fishes, at least seven orders of insects, crustaceans, and a diverse flora. Cyclic changes in the fauna and flora correlate with sedimentary cycles, which together reflect the repetitive development and extinction of large meromictic lakes.
Venus: Further Evidence of Vortex Circulation
Authors: Suomi Verner E. , Limaye Sanjay Shridhar
Published: October 2006

A space-time composite of polar stereographic ultraviolet images of Venus from Mariner 10 shows a remarkable circumpolar vortex. The vortex is characterized by a cloud which appears similar to dense terrestrial stratus having an albedo that is 50 percent higher. Spiral streaks converge into it from low latitudes, akin to the spiral bands of a hurricane. The bright visible polar cloud is not axisymmetric but has roughly an elliptical shape. The high brightness of the polar cloud suggests that it has a different origin from the rest of the Venus cloud cover.
Growth Lines in a Bivalve Mollusk: Subdaily Patterns and Dissolution of the Shell
Authors: Gordon J. , Carriker M. R.
Published: October 2006

Scanning electron micrographs of sections of the prismatic shell of the bivalve
Mercenaria mercenaria
reveal narrow subdaily growth striations. The width of these narrow lines, formed by concentrations of organic material, corresponds to the quantity of shell material that would be expected to dissolve during periods of anaerobic metabolism. The
p
H in the extrapallial fluid of the bivalve decreases when the valves are closed, and the amount of dissolution of shell is related to the duration of valve closure.
Paper-Marking Test for Chimpanzee: Simple Control for Social Cues
Authors: Premack David , Woodruff Guy , Kennel Keith
Published: October 2006

A series of paper-marking tests, modeled after tests widely applied to humans, was administered to Sarah, a "language"-trained Chimpanzee (
Pan troglodytes
). The test format was simple, economical, and controlled for social cues. The ape successfully made same-similar-different judgments on pictures of familiar objects when up to four questions were presented at the same time. Performance remained satisfactory on same-different judgments of novel pictures of alphabetic characters. Throughout the series of tests, the subject showed a superiority on same judgments.
Infrared Images of Jupiter at 5-Micrometer Wavelength During the Voyager 1 Encounter
Authors: Terrile Richard J. , Capps R. W. , Backman D. E. , Becklin E. E. , Cruikshank D. P. , Beichman C. A. , Brown R. H. , Westphal James A.
Published: October 2006

A coordinated program to observe Jupiter at high spatial resolution in the 5-micrometer wavelength region was undertaken to support Voyager 1 imaging and infrared radiation experiment targeting. Jupiter was observed over a 5-month period from Palomar and Mauna Kea observatories. The frequency of observations allowed the selection of interesting areas for closer Voyager examination and also provided good short-term monitoring of variations in cloud morphology. Significant global changes in the 5-micrometer distribution are seen over this time period.
Voyager 1 Encounter with the Jovian System
Authors: Stone E. C. , Lane A. L.
Published: October 2006

An overview of the Voyager 1 encounter with Jupiter is presented, including a brief discussion of the characteristics of the spacecraft and trajectory and highlights of the results which are described in the subsequent reports.
A Siting Policy for an Acceptable Nuclear Future
Authors: Burwell C. C. , Ohanian M. J. , Weinberg A. M.
Published: October 2006

A nuclear siting policy leading to a few, large concentrated sites, it is argued, is preferable in the long run to the present policy which could lead to many dispersed sites. Such a policy could be implemented incrementally if requirements for new nuclear generating capacity were met by adding reactors to the existing 100-odd sites. Such a concentrated nuclear siting policy would, to some extent, isolate nuclear activities while augmenting the strengths of the institutions responsible for managing them. Additionally, it would confer an element of permanence on the sites and thereby open new options for managing low level wastes and reactor decommissioning. These actions may improve the public acceptability of nuclear energy in the United States as well as lead to a more rational contained nuclear system in the long run.
Tournament Competition Fuels Computer Chess
Authors: Robinson Arthur L.
Published: October 2006

The din in the packed arena had hardly subsided to a mild roar, when suddenly the fans exploded once again. "What a move!" screamed one nearby spectator. "How did he ever find a way through that defense?" wondered another, overcome with admiration.
Interaction of the IL-2 Receptor with the
src
-Family Kinase p56
lck
: Identification of Novel Intermolecular Association
Authors: Hatakeyama Masanori , Kono Takeshi , Kobayashi Naoki , Kawahara Atsuo , Levin Steven D. , Perlmutter Roger M. , Taniguchi Tadatsugu
Published: October 2006

In the interleukin-2 (IL-2) system, intracellular signal transduction is triggered by the β chain of the IL-2 receptor (IL-2Rβ); however, the responsible signaling mechanism remains unidentified. Evidence for the formation of a stable complex of IL-2Rβ and the lymphocyte-specific protein tyrosine kinase p56
lck
is presented. Specific association sites were identified in the tyrosine kinase catalytic domain of p56
lck
and in the cytoplasmic domain of IL-2Rβ. As a result of interaction, IL-2Rβ became phosphorylated in vitro by p56
lck
. Treatment of T lymphocytes with IL-2 promotes p56
lck
kinase activity. These data suggest the participation of p56
lck
as a critical signaling molecule downstream of IL-2R via a novel interaction.
Detection of Singly Ionized Oxygen Around Jupiter
Authors: Pilcher C. B. , Morgan J. S.
Published: October 2006

Forbidden emission from singly ionized oxygen at wavelengths of 3726 and 3729 angstroms has been detected in the inner Jovian magnetosphere. The emission is present between ∼4 and ∼7 to 8 Jovian radii from the planet and appears concentrated in the magnetic equator. The line intensity ratio indicates the same plasma characteristics as those derived from observations of forbidden sulfur emission.
Observations of Energetic Ions and Electrons in Saturn's Magnetosphere
Authors: Trainor J. H. , McDonald F. B. , Schardt A. W.
Published: October 2006

The passage of Pioneer 11 by Saturn provided a detailed view of a planetary magnetosphere that is intermediate between those of Jupiter and Earth in both scale and the complexity of its dynamic processes. It appears to have at least three distinct regions: (i) an outer magnetosphere, extending from 17 to 7.5 Saturn radii, that resembles that of Earth in many important aspects; (ii) a slot region, between 7.5 and 4 Saturn radii, where a marked decrease in all protons and low-energy electrons is observed; and (iii) an inner region, extending from 4 Saturn radii to the ring edge, that features a sharp increase in the proton flux extending to energies greater than 20 million electron volts. A cutoff of both proton and electron fluxes occurred just beyond the nominal edge of the A ring.
Boll Weevil Eradication
Authors: Perkins John H.
Published: October 2006

Some representatives of the cotton industry and of the entomological profession advocate efforts to eradicate the boll weevil. This coalition originated in 1958 from a complex of socioeconomic changes in cotton production and scientific developments in entomology. The results of a pilot eradication experiment (1971 to 1973) were controversial, and the debate was inhibited by social pressures upon the entomological profession. Substantial conceptual difficulties also attend evaluations of eradication experiments. A new trial eradication program is under way. If its evaluation is not to be warped by problems similar to the earlier ones, both the social and scientific aspects of eradication must be recognized and steps must be taken to ensure a full and open debate.
Fallout Plutonium in an Alkaline, Saline Lake
Authors: Simpson H. J. , Trier R. M. , Olsen C. R. , Hammond D. E. , Ege A. , Miller L. , Melack J. M.
Published: October 2006

Plutonium isotopes, derived from global fallout following atmospheric testing of nuclear weapons, have been measured in the water and sediments of a natural alkaline, saline lake. The activities of fallout plutonium in the water column are about two orders of magnitude greater than in most freshwater lakes, where these nuclides are found predominantly in the sediments.
Bioluminescence in Mesopelagic Squid: Diel Color Change During Counterillumination
Authors: Young Richard Edward , Mencher Frederick M.
Published: October 2006

Two species of mesopelagic squid greatly altered the color of their bioluminescence during counterillumination. The color change was triggered by changes in water temperature corresponding to those normally encountered by these vertically migrating animals. These squid can probably conceal themselves under the different colors of downwelling light that they encounter in their day and night habitats.
Foraminifera: Distribution of Provinces in the Western North Atlantic
Authors: Buzas M. A. , Culver S. J.
Published: October 2006

All published distributional data on recent benthic foraminifera of the North American Atlantic continental margin were archived into computerized catalogs. Cluster analysis of these data delimited seven large, marginally overlapping provinces exhibiting a congruous relationship with western North Atlantic water masses. The single major latitudinal faunal change occurs at Cape Hatteras.
Viviparity and Intrauterine Feeding in a New Holocephalan Fish from the Lower Carboniferous of Montana
Authors: Lund Richard
Published: October 2006

A new species of Lower Carboniferous holocephalan chondrichthyan,
Delphyodontos dacriformes
, is described from two fetal specimens. The well-developed slashing and piercing dentition, enlargement of the abdominal region, and fecal material indicate the probable evolution of intrauterine oophagy and viviparity in Paleozoic Chondrichthyes.
Kin Selection: Its Components
Authors: Wade Michael J.
Published: October 2006

Change in gene frequency under kin selection is the sum of two components, namely, Δ̅
q
̅
I
, a change in gene frequency caused by individual selection, and Δ
q
G
, a change caused by group selection. For the evolution of altruistic traits by kin selection, Δ̅
q
̅
I
is always negative—that is, individual selection operates against altruism—and Δ
q
G
is always positive, so that selection between groups favors altruism. Hamilton's rule specifies the conditions under which Δ
q
G
> |Δ̅
q
̅
I
|—that is, the conditions necessary for intergroup selection to override individual selection.
Tectonic Evolution of the Terrestrial Planets
Authors: Head James W. , Solomon Sean C.
Published: October 2006

The style and evolution of tectonics on the terrestrial planets differ substantially. The style is related to the thickness of the lithosphere and to whether the lithosphere is divided into distinct, mobile plates that can be recycled into the mantle, as on Earth, or is a single spherical shell, as on the moon, Mars, and Mercury. The evolution of a planetary lithosphere and the development of plate tectonics appear to be influenced by several factors, including planetary size, chemistry, and external and internal heat sources. Vertical tectonic movement due to lithospheric loading or uplift is similar on all of the terrestrial planets and is controlled by the local thickness and rheology of the lithosphere. The surface of Venus, although known only at low resolution, displays features both similar to those on Earth (mountain belts, high plateaus) and similar to those on the smaller planets (possible impact basins). Improved understanding of the tectonic evolution of Venus will permit an evaluation of the relative roles of planetary size and chemistry in determining evolutionary style.
Thermal Tides in the Dusty Martian Atmosphere: A Verification of Theory
Authors: Zurek R. W. , Leovy C. B.
Published: October 2006

Major features of the daily surface pressure oscillations observed by the Viking landers during the two great dust storms on Mars in 1977 can be explained in terms of the classical atmospheric tidal theory developed for the earth's atmosphere. The most dramatic exception is the virtual disappearance of only the diurnal tide at Viking Lander 1 just before the second storm. This disappearance is attributed to destructive interference between the usually westward-traveling tide and an eastward-traveling diurnal Kelvin mode generated by orographically induced differential heating. The continuing Viking Lander 1 pressure measurements can be used with the model to monitor future great dust storms.
Nullisomic
Tetrahymena:
Eliminating Germinal Chromosomes
Authors: Bruns Peter J. , Brussard Trudy E. B.
Published: October 2006

Germinal and somatic functions in
Tetrahymena
are performed separately by the micro- and macronuclei, respectively. Cells with haploid micronuclei were mated with diploids to yield monosomic progeny. These were induced to undergo a form of self-fertilization, generating cells lacking both copies of one or more of the five chromosomes in the micronucleus while still possessing a complete macronuclear genome.
Stromatoporoid Growth Rhythms and Rates
Authors: Meyer Franz O.
Published: October 2006

Stromatoporoids are major contributors to framework construction in Paleozoic reefs. The Devonian species
Parallellostroma densilaminata
(Fagerstrom),
P. winchelli
(Galloway and Ehlers), and
Stictostroma
sp. form large rhythmically structured colonies that competitively overgrow corals. Their competitive interactions and important role as reef builders place considerable value on growth rate information. Identification of common growth periods in these interacting species provides a method for quantifying vertical and lateral stromatoporoid growth and a means for identifying an annual periodicity of calcification.
Is a New Evolutionary Synthesis Necessary?
Authors: Stebbins G. Ledyard , Ayala Francisco J.
Published: October 2006

The current (synthetic) theory of evolution has been criticized on the grounds that it implies that macroevolutionary processes (speciation and morphological diversification) are gradual. The extent to which macroevolution is gradual or punctuational remains to be ascertained. Macroevolutionary processes are underlain by microevolutionary phenomena and are compatible with the synthetic theory of evolution. But microevolutionary principles are compatible with both gradualism and punctualism; therefore, logically they entail neither. Thus, macroevolution and microevolution are decoupled in the important sense that macroevolutionary patterns cannot be deduced from microevolutionary principles.
Organization of the Human and Mouse Low-affinity FcγR Genes: Duplication and Recombination
Authors: Qiu Wei Qiao , de Bruin Derik , Brownstein Bernard H. , Pearse Roger , Ravetch Jeffrey V.
Published: October 2006

Receptors for immunoglobulin G immune complexes (FcγRII and FcγRIII) are expressed on most hematopoietic cells and show much structural and functional diversity. In order to determine the genetic basis for this diversity, a family of genes encoding the human and mouse receptors was isolated and characterized. Humans have five distinct genes for low-affinity FcγRs, in contrast to two in the mouse. With the use of yeast artificial chromosomes, the genes encoding the human receptors were oriented and linked, which established the structure of this complex locus. Comparison of the human and mouse genes generated a model for the evolutionary amplification of this locus.
Acyclic Stereocontrol Through the Aldol Condensation
Authors: Heathcock Clayton H.
Published: October 2006

For the scientist who wishes to synthesize complex organic compounds, the most difficult problem is often establishing the correct configuration at the various chiral centers as the synthesis is being carried out. In the past decade, there has been an increasing effort to find direct solutions to this problem, which is particularly acute in the synthesis of acyclic and other conformationally flexible molecules. One of the oldest organic reactions, the aldol condensation, is emerging as a powerful tool for use in achieving such stereocontrol.
Oxygen Deficiency in
Spartina alterniflora
Roots: Metabolic Adaptation to Anoxia
Authors: Mendelssohn I. A. , McKee K. L. , Patrick W. H.
Published: October 2006

The aerenchyma (air-space) tissue in the wetland macrophyte
Spartina alterniflora
conveys sufficient oxygen to roots for predominately aerobic respiration in moderately, but not highly, reduced substrates. Continuously flooded plants survive by respiring anaerobically, although growth is decreased. Two metabolic adaptations to flooding are displayed in this species, depending on the degree of soil reduction.
Virginia Barrier Island Configuration: A Reappraisal
Authors: Leatherman Stephen P. , Rice Thomas E. , Goldsmith Victor
Published: October 2006

The 12 Virginia barrier islands are divided into three groups on the basis of historical retreat rates and characteristics. The growth and reversal of inlet offsets is a long-term event that results from the operation of known coastal processes. Both geomorphic evidence and wave refraction analyses indicate that shoreline irregularity will diminish with time. There is no basis for the prediction (or expectation) that cape-like features will evolve along this shoreline.
Some Recent Advances in Computer Graphics
Authors: Whitted Turner
Published: October 2006

Computer graphics, no longer a novelty, is on its way to becoming the preferred interface between humans and computers. Continued advances in the development of graphics algorithms are improving the quality and usefulness of this interface. Decreasing hardware costs have enabled an expansion of graphics into more diverse applications.
Molecular Cloning of Polyoma Virus DNA in
Escherichia coli
: Lambda Phage Vector System
Authors: Chan Hardy W. , Israel Mark A. , Garon Claude F. , Rowe Wallace P. , Martin Malcolm A.
Published: October 2006

The biological activity of recombinant phage and recombinant phage DNA containing monomeric or dimeric polyoma DNA inserts was examined in mice and cultured mouse cells. Recombinant preparations containing a single copy of viral DNA were invariably noninfectious; molecules containing a dimeric polyoma DNA insert were at least seven orders of magnitude less infectious than polyoma virions after parenteral inoculation. No infection was detected with any recombinant preparation after oral administration.
Poliovirus Mutants Resistant to Neutralization with Soluble Cell Receptors
Authors: Kaplan Gerardo , Peters David , Racaniello Vincent R.
Published: October 2006

Poliovirus mutants resistant to neutralization with soluble cellular receptor were isolated. Replication of soluble receptor-resistant (
srr
) mutants was blocked by a monoclonal antibody directed against the HeLa cell receptor for poliovirus, indicating that the mutants use this receptor to enter cells. The
srr
mutants showed reduced binding to HeLa cells and cell membranes. However, the reduced binding phenotype did not have a major impact on viral replication, as judged by plaque size and one-step growth curves. These results suggest that the use of soluble receptors as antiviral agents could lead to the selection of neutralization-resistant mutants that are able to bind cell surface receptors, replicate, and cause disease.