bluuebunny/crossref_metadata_2025 huggingface dataset:
A Virus-Encoded "Superantigen" in a Retrovirus-Induced Immunodeficiency Syndrome of Mice
Authors: Hügin Ambros W. , Vacchio Melanie S. , Morse Herbert C.
Published: October 2006

The development of an immunodeficiency syndrome of mice caused by a replication-defective murine leukemia virus (MuLV) is paradoxically associated with a rapid activation and proliferation of CD4
+
T cells that are dependent on the presence of B cells. The responses of normal spleen cells to B cell lines that express the defective virus indicated that these lines express a cell surface determinant that shares "superantigenic" properties with some microbial antigens and Mls-like self antigens. This antigen elicited a potent proliferative response that was dependent on the presence of CD4
+
T cells and was associated with selective expansion of cells bearing V
β
5. This response was markedly inhibited by a monoclonal antibody specific for the MuLV
gag
-encoded p30 antigen.
Inhibition of Entry of HIV-1 in Neural Cell Lines by Antibodies Against Galactosyl Ceramide
Authors: Harouse Janet M. , Bhat Shama , Spitalnik Steven L. , Laughlin Mark , Stefano Kelly , Silberberg Donald H. , Gonzalez-Scarano Francisco
Published: October 2006

Although the CD4 molecule is the principal cellular receptor for the human immunodeficiency virus (HIV), several CD4-negative cell lines are susceptible to infection with one or more HIV strains. These findings indicate that there are alternate modes of viral entry, perhaps involving one or more receptor molecules. Antibodies against galactosyl ceramide (galactocerebroside, or GalC) inhibited viral internalization and infection in two CD4-negative cell lines derived from the nervous system: U373-MG and SK-N-MC. Furthermore, recombinant HIV surface glycoprotein gp120 bound to GalC but not to other glycolipids. These results suggest a role for GalC or a highly related molecule in HIV entry into neural cells.
Variations of Upper Mantle Structure under the Pacific Ocean
Authors: Leeds Alan R. , Knopoff Leon , Kausel Edgar G.
Published: October 2006

The inversion of Rayleigh wave dispersion data for the Pacific Ocean shows that lithospheric thickness increases systematically with age. The lid to the low-velocity channel is very thin or absent near the ridge crest; the low-velocity channel may be absent in the oldest parts of the ocean.
Aldosterone-Induced Protein in Toad Urinary Bladder
Authors: Benjamin William B. , Singer Irwin
Published: October 2006

Simultaneous electrophysiological and biochemical experiments demonstrated a specific aldosterone-induced protein in paired urinary hemibladders isolated from the toad "
Bufo marinus
. Whenever aldosterone stimulated short-circuit current, aldosterone specifically increased [
35
S]methionine incorporation into a low-molecular-weight protein (about 12,000). Comparative studies with dexamethasone and insulin and inhibitory studies with spironolactone and actinomycin D suggest mineralocorticoid specificity.
Studies of Squeezing: Handedness, Responding Hand, Response Force, and Asymmetry of Readiness Potential
Authors: Kutas Marta , Donchin Emanuel
Published: October 2006

Eleven subjects squeezed an electronic dynamometer, at each of three force levels, with both their right and left hands. In right-handed subjects the premovement "readiness" potentials were larger over the hemisphere contralateral to the responding hand. Left-handed subjects show contralateral dominance when responding with the right hand but not when responding with the left hand. The data suggest that in the potentials studied there is a component associated with the preparation to perform a specific movement, rather than with generalized preparatory processes.
Tilt Precursors before Earthquakes on the San Andreas Fault, California
Authors: Johnston M. J. S. , Mortensen C. E.
Published: October 2006

An array of 14 biaxial shallow-borehole tiltmeters (at 10
-7
radian sensitivity) has been installed along 85 kilometers of the San Andreas fault during the past year. Earthquake-related changes in tilt have been simultaneously observed on up to four independent instruments. At earthquake distances greater than 10 earthquake source dimensions, there are few clear indications of tilt change. For the four instruments with the longest records (> 10 months), 26 earthquakes have occurred since July 1973 with at least one instrument closer than 10 source dimensions and 8 earthquakes with more than one instrument within that distance. Precursors in tilt direction have been observed before more than 10 earthquakes or groups of earthquakes, and no similar effect has yet been seen without the occurrence of an earthquake.
Multienzyme Systems of DNA Replication
Authors: Schekman Randy , Weiner Alan , Kornberg Arthur
Published: October 2006

Replication is accomplished by multienzyme systems whose operations are usefully considered in respect to three stages of the process: initiation, elongation, and termination.

1) Initiation entails synthesis of a short RNA fragment that serves as primer for the elongation step of DNA synthesis. This stage, probed by SS phage DNA templates, reveals three distinctive and highly specific systems in
E. coli
. The Ml3 DNA utilizes RNA polymerase in a manner that may reflect how plasmid elements are replicated in the cell. The φX174 DNA does not rely on RNA-polymerase, but requires instead five distinctive proteins which may belong to an apparatus for initiating a host chromosome replication cycle at the origin. The G4 DNA, also independent of RNA polymerase, needs simply the
dna
G protein for its distinctive initiation and may thus resemble the system that initiates the replication fragments at the nascent growing fork. In each case it is essential that in vitro the DNA-unwinding protein coat the viral DNA and influence its structure.

2) Elongation is achieved in every case by the multisubunit, holoenzyme form of DNA polymerase III. Copolymerase III, which is an enzyme subunit, and adenosine triphosphate are required to form a proper complex with the primer template but appear dispensable for the ensuing chain growth by DNA polymerase.

3) Termination requires excision of the RNA priming fragment, filling of gaps and sealing of interruptions to produce a covalently intact phosphodiester backbone. DNA polymerase I has the capacity for excision and gap-filling and DNA ligase is required for sealing.

What once appeared to be a simple DNA polymerase-mediated conversion of a single-strand to a duplex circle is now seen as a complex series of events in which diverse multienzyme systems function. Annoyance with the difficulties in resolving and reconstituting these systems is tempered by the conviction that these are the very systems used ,by the cell in replicating its chromosome and extrachromosomal elements. Thus, understanding of the regulation of replication events in the cell, their localization at membrane surfaces and integration with cell division, and their coordination with phage DNA maturation and particle assembly will all be advanced by knowledge of the components of the replicative machinery.
Scaling Stride Frequency and Gait to Animal Size: Mice to Horses
Authors: Heglund Norman C. , Taylor C. Richard , McMahon Thomas A.
Published: October 2006

The stride frequency at which animals of different size change from one gait to another (walk, trot, gallop) changes in a regular manner with body mass. The speed at the transition from trot to gallop can be used as an equivalent speed for comparing animals of different size. This transition point occurs at lower speeds and higher stride frequencies in smaller animals. Plotting stride frequency at the trot-gallop transition point as a function of body mass in logarithmic coordinates yields a straight line.
Heat Flow and Convection Experiments aboard Apollo 17
Authors: Grodzka Philomena G. , Bannister Tommy C.
Published: October 2006

Experiments conducted aboard Apollo 17 by astronaut Ronald E. Evans showed that in uncovered liquids convection driven by surface tension can occur at lower temperature gradients in low gravity (about 10-
8
g
) than in 1
g
. In completely confined fluids (no liquid-gas interface) vibrations caused by spacecraft and astronaut movements increased the heat transfer considerably over the pure conduction case.
Solar Nitrogen: Evidence for a Secular Increase in the Ratio of Nitrogen-15 to Nitrogen-14
Authors: Kerridge John F.
Published: October 2006

Solar wind nitrogen, implanted in lunar soil samples, exhibits isotopic variations that are related to the time, although not to the duration, of implantation, with earlier samples characterized by lower ratios of nitrogen-15 to nitrogen-14. An increase in the solar nitrogen-15 content during the lifetime of the lunar regolith is probably caused by spallation of oxygen-16 in the surface regions of the sun.
The Imaging Photopolarimeter Experiment on Pioneer 11
Authors: Baker A. L. , Baker L. R. , Beshore E. , Blenman C. , Castillo N. D. , Chen Y.-P. , Doose L. R. , Elston J. P. , Fountain J. W. , Gehrels T. , Kendall J. H. , KenKnight C. E. , Norden R. A. , Swindell W. , Tomasko M. G. , Coffeen D. L.
Published: October 2006

For 2 weeks continuous imaging, photometry, and polarimetry observations were made of Jupiter and the Galilean satellites in red and blue light from Pioneer 11. Measurements of Jupiter's north and south polar regions were possible because the spacecraft trajectory was highly inclined to the planet's equatorial plane. One of the highest resolution images obtained is presented here along with a comparison of a sample of our photometric and polarimetric data with a simple model. The data seem consistent with increased molecular scattering at high latitudes.
Weather Variability, Climatic Change, and Grain Production
Authors: Thompson Louis M.
Published: October 2006

A cooling trend in the world's climate would have serious effects in the monsoon belts depending on whether or not the recent changes in snow and ice cover in the polar regions were responsible for the droughts in Africa and the failure of the monsoons over South Asia. The cooling and shrinking of the atmosphere at the higher latitudes is believed to have brought the subtropical anticyclones nearer to the tropical rainbelt and have caused a shifting of the monsoon belt.

The regions that would be most severely affected by a continuation of the cooling trend to the year 2000 would be the higher latitudes (above 50 degrees) where spring wheat is grown and the warm band below 30 degrees latitude where rice is the principal grain crop.

Weather variability is a much more important consideration in grain production than a cooling trend. Our highest yields are made when weather is near normal or slightly cooler than normal. It is when weather variables deviate greatly from normal that yields are lowest. Even if the weather does trend toward the coolness of a century ago yields will not be reduced significantly unless the weather becomes more variable.
Glia Maturation Factor: Effect on Chemical Differentiation of Glioblasts in Culture
Authors: Lim Ramon , Turriff David E. , Troy Shuang S. , Moore Blake W. , Eng Lawrence F.
Published: October 2006

A protein factor from the adult brain increases the concentrations of adenosine 3′,5′-monophosphate and S-100 protein in glioblasts in culture. Such changes are correlated with the outgrowth of cell processes.
Etch Patterns on Calcareous Sediment Grains: Petrographic Evidence of Marine Dissolution of Carbonate Minerals
Authors: Alexandersson E. Torbjörn
Published: October 2006

Scanning electron microscopy reveals that carbonate grains in sublittoral sediments in the North Sea have surfaces with a microscopic etch relief. In structurally complex skeletal grains, the relief grades into marginal corrosion zones. The etch patterns are caused by dissolution of calcium carbonate, taking place at the shallow sea floor. Carbonate phases affected are calcite, aragonite, and a spectrum of magnesian calcites.
Doctorates Granted to Women and Minority Group Members
Authors: McCarthy Joseph L. , Wolfle Dael
Published: October 2006

The AAU universities, a prime recruiting ground for new faculty members in selective colleges and research-oriented universities, are significantly increasing the number of doctorates awarded to women and minority members and are decreasing the numbers awarded to majority males. Between 1969-72 and 1972-75, doctorates awarded by AAU universities to majority men declined by 9 percent; to majority women increased by 34 percent; to minority men increased by 61 percent; and to minority women increased by 133 percent.

The field distribution is very uneven. In some fields women with doctorates are fairly numerous, but most of these fields are ones in which women have for long constituted a significant portion of the total. In other fields, notably engineering and some of the physical sciences, it is still difficult to find women with doctorates from the universities in which large numbers of new faculty members receive their graduate education.

Increasing numbers of minority students are earning doctorates in some fields, but in many fields the number is still very low. The several minority groups show quite different patterns of distribution among fields of specialization. The two smaller groups—American Indian and Spanish-origin—are most like the white majority in distribution by fields. Black doctorates are concentrated in education, with relatively few in the sciences. Students of Asian ancestry are heavily concentrated in engineering and the natural sciences.
Sequence-Specific Antirepression of Histone H1-Mediated Inhibition of Basal RNA Polymerase II Transcription
Authors: Croston Glenn E. , Kerrigan Leslie A. , Lira Lucy M. , Marshak Daniel R. , Kadonaga James T.
Published: October 2006

To understand the principles of control and selectivity in gene expression, the biochemical mechanisms by which promoter- and enhancer-binding factors regulate transcription by RNA polymerase II were analyzed. A general observed repressor of transcription was purified and identified as histone H1. Since many aspects of H1 binding to naked DNA resemble its interaction with chromatin, purified H1 bound to naked DNA was used as a model for the repressed state of the DNA template. Three sequence-specific transcription factors, Sp1, GAL4-VP16, and GAGA factor, were shown to counteract H1-mediated repression (antirepression). In addition, Sp1 and GAL4-VP16, but not the GAGA factor, activated transcription in the absence of H1. Therefore, true activation and antirepression appear to be distinct activities of sequence-specific factors. Furthermore, transcription antirepression by GAL4-VP16 was sustained for several rounds of transcription. These findings, together with previous studies on H1, suggest that H1 participates in repression of the genome in the ground state and that sequence-specific transcription factors induce selected genes by a combination of true activation and release of basal repression that is mediated at least in part by H1.
Recombinase-Mediated Gene Activation and Site-Specific Integration in Mammalian Cells
Authors: O'Gorman Stephen , Fox Daniel T. , Wahl Geoffrey M.
Published: October 2006

A binary system for gene activation and site-specific integration, based on the conditional recombination of transfected sequences mediated by the FLP recombinase from yeast, was implemented in mammalian cells. In several cell lines, FLP rapidly and precisely recombined copies of its specific target sequence to activate an otherwise silent β-galactosidase reporter gene. Clones of marked cells were generated by excisional recombination within a chromosomally integrated copy of the silent reporter. By the reverse reaction, integration of transfected DNA was targeted to a specific chromosomal site. The results suggest that FLP could be used to mosaically activate or inactivate transgenes for analysis of vertebrate development, and to efficiently integrate transfected DNA at predetermined chromosomal locations.
An Experiment in Earthquake Control at Rangely, Colorado
Authors: Raleigh C. B. , Healy J. H. , Bredehoeft J. D.
Published: October 2006

An experiment in an oil field at Rangely, Colorado, has demonstrated the feasibility of earthquake control. Variations in seismicity were produced by controlled variations in the fluid pressure in a seismically active zone. Precise earthquake locations revealed that the earthquakes clustered about a fault trending through a zone of high pore pressure produced by secondary recovery operations. Laboratory measurements of the frictional properties of the reservoir rocks and an in situ stress measurement made near the earthquake zone were used to predict the fluid pressure required to trigger earthquakes on preexisting fractures. Fluid pressure was controlled by alternately injecting and recovering water from wells that penetrated the seismic zone. Fluid pressure was monitored in observation wells, and a computer model of the reservoir was used to infer the fluid pressure distributions in the vicinity of the injection wells. The results of this experiment confirm the predicted effect of fluid pressure on earthquake activity and indicate that earthquakes can be controlled wherever we can control the fluid pressure in a fault zone.
A Western Boundary Current in the Gulf of Mexico
Authors: Sturges Wilton , Blaha John P.
Published: October 2006

The curl of the wind stress over the Gulf of Mexico, during the winter and again in the summer, is similar to that over the central North Atlantic Ocean. An anticyclonic gyre is nearly always found in the western gulf, and we suggest that there is a typical western boundary current, similar in many important respects to the Gulf Stream. The flow appears to be strongest in winter and summer, in phase with the wind curl forcing, and there is evidence that this response is at least partially baroclinic. The deep baroclinic gyre persists when the wind curl vanishes. The winter transport is roughly half that of the Florida Current.
Eleven-Year Variation in Polar Ozone and Stratospheric-Ion Chemistry
Authors: Ruderman M. A. , Foley H. M. , Chamberlain J. W.
Published: October 2006

A mechanism for producing an 11-year oscillation in ozone over the polar caps is the modulation of galactic cosmic rays by the solar wind. This mechanism has been shown to give the observed phase in ozone oscillations and the correct qualitative dependence on latitude. However, the production of nitrogen atoms from cosmic-ray collisions seems inadequate to account for the ozone amplitude. Negative ions are also produced as a result of cosmic-ray ionization, and negative-ion chemistry may be of importance in the stratosphere. Specifically, NO
x
–
may go through a catalytic cycle in much the same fashion as NO
x
, but with the important distinction that it does not depend on oxygen atoms to complete the cycle. Estimates of the relevant rates of reaction suggest that negative ions may be especially important over the winter polar cap.
Plates of the Dinosaur
Stegosaurus
: Forced Convection Heat Loss Fins?
Authors: Farlow James O. , Thompson Carl V. , Rosner Daniel E.
Published: October 2006

It is suggested that the plates along the arched back and tail of
Stegosaurus
served an important thermoregulatory function as forced convection "fins." Wind tunnel experiments on finned models, internal heat conduction calculations, and direct observations of the morphology and internal structure of stegosaur plates support this hypothesis, demonstrating the comparative effectiveness of the plates as heat dissipaters, controllable through input blood flow rate, temperature, and body orientation (with respect to wind)
.
Masses of the Galilean Satellites of Jupiter
Authors: Ferraz-Mello S.
Published: October 2006

Numerical data derived from the observation of the four great satellites of Jupiter are compared with the values obtained through Sampson's theory by using the new JPL (Jet Propulsion Laboratory) system of masses. It is not possible to fit the coefficient of the free oscillation in the longitude of Ganymede, whose argument is l
3
- ω̅
4
(the mean longitude of Ganymede referred to the proper apse of Callisto), and the mass of Callisto derived from the path of Pioneer 10.
Denitrification Studies with
13
N-Labeled Nitrate
Authors: Gersberg Richard , Krohn Kenneth , Peek Neal , Goldman Charles R.
Published: October 2006

Nitrate labeled with
13
N (
13
NO
3
–
) was produced in a cyclotron by the
16
O(p, α)
13
N reaction with protons having energies of 14.5 million electron volts. The
13
NO
3
–
was used as a tracer for direct quantitative measurements of denitrification rates in soils from flooded rice fields. The
13
N technique provides a new tracer method for the measurement of denitrification rates in natural systems over short time intervals, without changing the concentration of NO
3
–
in the system.
Laser Ablation Studies of the Role of the
Drosophila
Oocyte Nucleus in Pattern Formation
Authors: Montell Denise J. , Keshishian Haig , Spradling Allan C.
Published: October 2006

Somatic and germline cells interact during oogenesis to establish the pattern axes of the
Drosophila
eggshell and embryo. The role of the oocyte nucleus in pattern formation was tested with the use of laser ablation. Ablation in stage 6 to 9 egg chambers caused partial or complete ventralization of the eggshell, phenotypes similar to those of eggs produced by
gurken
or
torpedo
females. Accumulation of
vasa
protein at the posterior pole of treated oocytes was also disrupted. Thus the oocyte nucleus is required as late as stage 9 for dorsoventral patterning within the follicle cells and for polar plasm assembly in the oocyte.
Short-Rerm Mortality Predictions for Critically Ill Hospitalized Adults: Science and Ethics
Authors: Knaus William A. , Wagner Douglas P. , Lynn Joanne
Published: October 2006

Modern life-sustaining therapy often succeeds in postponing death but may be ineffective at restoring health. Decisions that influence the time and circumstances of an individual's death are now common and require an accurate and comprehensive characterization of likely outcome. Evaluation of alternative outcomes requires acknowledgment that most patients find some outcomes to be worse than death. Improved understanding of major predictors of patient outcome, combined with rapidly expanding technical abilities to collect and manipulate large amounts of detailed clinical data, have created a new intellectual and technical basis for estimating outcomes from intensive medical care. Such objective probability estimates, such as the system described here, can reduce uncertainty about difficult clinical decisions and can be used by physicians, patients, and society to reorient health care toward more scientifically and ethically defensible approaches.
Dual Role of the
Drosophila
Pattern Gene
tailless
in Embryonic Termini
Authors: Steingrímsson Eiríkur , Pignoni Francesca , Liaw Gwo-Jen , Lengyel Judith A.
Published: October 2006

One of the first zygotically active genes required for formation of the terminal domains of the
Drosophila
embryo is
tailless
(
tll
). Expression of the
tll
gene is activated ectopically in gain-of-function mutants of the maternal terminal gene
torso
(
tor
); this suggests that
tor
normally activates the
tll
gene in the termini. Ectopic expression of
tll
under the control of an inducible promoter results in differentiation of ectopic terminal-specific structures, the Filzkörper, and leads to the activation of at least one gene,
hunchback
, that is required to form these structures. Ectopic expression of the
tll
gene also represses segmentation by repressing the gap genes
Krüppel
and
knirps
and probably also pair rule genes.
Light Scattering by Irregular Randomly Oriented Particles
Authors: Chýlek Petr , Grams G. W. , Pinnick R. G.
Published: October 2006

A method for calculating light scattering by irregular randomly oriented particles yields results that are in good agreement with experimental data. The method is based on the assumption that surface waves are present in scattering by spherical particles, but they are absent in scattering by irregular particles.
Light Flashes Observed on Skylab 4: The Role of Nuclear Stars
Authors: Rothwell P. L. , Filz R. C. , McNulty P. J.
Published: October 2006

The astronauts on Skylab 4 observed bursts of intense visual light flash activity when their spacecraft passed through the South Atlantic Anomaly. Flash rates as high as 20 per minute have in the past been considered unexpectedly high. When the effect of nuclear interactions in and near the retina is included, the apparent anomaly is removed.
Pontine Reticular Formation Neurons: Relationship of Discharge to Motor Activity
Authors: Siegel Jerome M. , McGinty Dennis J.
Published: October 2006

The discharge correlates of pontine reticular formation units were investigated in unrestrained cats. In agreement with previous investigations using immobilized preparations, we found that these cells had high rates of activity in rapid eye movement sleep, and responded in waking to somatic, auditory, and vestibular stimuli at short latencies, many having polysensory responses and exhibiting rapid "habituation." However, despite the sensory responses of these cells, most unit activity could not be explained by the presence of sensory stimuli. Intense firing occurred in association with specific movements. Units deprived of their adequate somatic, vestibular, and auditory stimuli showed undiminished discharge rates during motor activity. Discrete sensory stimuli evoked sustained unit firing only when they also evoked a motor response. We conclude that activity in pontine reticular formation neurons is more closely related to motor output than to sensory input.
Cerebrospinal Fluid Production: Stimulation by Cholera Toxin
Authors: Epstein Mel H. , Feldman Arthur M. , Brusilow Saul W.
Published: October 2006

Large increases in the production of cerebrospinal fluid have been observed after the intraventricular administration of cholera toxin. Because cholera toxin stimulates adenylate cyclase, the data suggest that adenosine 3′,5′-monophosphate plays a role in cerebrospinal fluid production.
Mathematics and Computer Science: Coping with Finiteness
Authors: Knuth Donald E.
Published: October 2006

By presenting these examples, I have tried to illustrate four main points.

1) Finite numbers can be really enormous, and the known universe is very small. Therefore the distinction between finite and infinite is not as relevant as the distinction between realistic and unrealistic.

2) In many cases there are subtle ways to solve very large problems quickly, in spite of the fact that they appear at first to require examination of too many possibilities.

3) There are also cases where we can prove that a fairly natural problem is intrinsically hard, far beyond our conceivable capabilities.

4) It takes a good deal of skill to decide whether a given problem is in the easy or hard class; but even if a problem does turn out to be hard there are useful and interesting ways to change it into one that can be done satisfactorily.
Temperatures of the Martian Surface and Atmosphere: Viking Observation of Diurnal and Geometric Variations
Authors: Kieffer Hugh H. , Christensen Philip R. , Martin Terry Z. , Miner Ellis D. , Palluconi Frank D.
Published: October 2006

Selected observations made with the Viking infrared thermal mapper after the first landing are reported. Atmospheric temperatures measured at the latitude of the Viking 2 landing site (48°N) over most of a martian day reveal a diurnal variation of at least 15 K, with peak temperatures occurring near 2.2 hours after noon, implying significant absorption of sunlight in the lower 30 km of the atmosphere by entrained dust. The summit temperature of Arsia Mons varies by a factor of nearly two each day; large diurnal temperature variation is characteristic of the south Tharsis upland and implies the presence of low thermal inertia material. The thermal inertia of material on the floors of several typical large craters is found to be higher than for the surrounding terrain; this suggests that craters are somehow effective in sorting aeolian material. Brightness temperatures of the Viking 1 landing area decrease at large emission angles; the intensity of reflected sunlight shows a more complex dependence on geometry than expected, implying atmospheric as well as surface scattering.
Angiotensin Converting Enzyme: Induction by Steroids in Rabbit Alveolar Macrophages in Culture
Authors: Friedland Joan , Setton Charlotte , Silverstein Emanuel
Published: October 2006

Dexamethasone and prednisone in physiologic range increased angiotensin converting enzyme 7- to 16-fold in comparison to control in 3 days at maximal stimulation (4 n
M
steroid) in rabbit alveolar macrophages in culture. The increase was inhibited by actinomycin D (0.1 μg/ml) and 1 μ
M
cycloheximide, suggesting that de novo transcription and enzyme synthesis are responsible for the increased enzyme activity. This result is evidence for a regulatory mechanism for angiotensin converting enzyme, which is important in blood pressure control.
Systemic Delivery of Recombinant Proteins by Genetically Modified Myoblasts
Authors: Barr Eliav , Leiden Jeffrey M.
Published: October 2006

The ability to stably deliver recombinant proteins to the systemic circulation would facilitate the treatment of a variety of acquired and inherited diseases. To explore the feasibility of the use of genetically engineered myoblasts as a recombinant protein delivery system, stable transfectants of the murine C2C12 myoblast cell line were produced that synthesize and secrete high levels of human growth hormone (hGH) in vitro. Mice injected with hGH-transfected myoblasts had significant levels of hGH in both muscle and serum that were stable for at least 3 weeks after injection. Histological examination of muscles injected with β-galactosidase-expressing C2C12 myoblasts demonstrated that many of the injected cells had fused to form multinucleated myotubes. Thus, genetically engineered myoblasts can be used for the stable delivery of recombinant proteins into the circulation.
Requirement for Cotolerogenic Gene Products in the Clonal Deletion of I-E Reactive T Cells
Authors: Woodland David , Happ Mary Pat , Bill Jerome , Palmer Ed
Published: October 2006

T cells that express the T cell receptor V
β
5.2 domain react with the class II major histocompatibility complex (MHC) molecule I-E, and V
β
5.2
+
T cells are deleted in mouse strains that express I-E glycoproteins. By examination of genetically defined recombinant inbred (RI) mouse strains, it was found that the deletion was dependent on the expression of I-E and one of a limited number of non-MHC gene products (cotolerogens). The gene encoding one of these cotolerogens maps to chromosome 12 and is linked to the endogenous provirus Mtv-9. These observations suggest that the I-E-mediated and minor lymphocyte-stimulating antigen (Mls)-mediated deletions of αβ T cells from the repertoire are similar; both require the expression of a class II MHC glycoprotein and a second non-MHC gene product.
Relation Between Earthquakes, Weather, and Soil Tilt
Authors: Wood M. D. , King N. E.
Published: October 2006

Two years of local earthquake, temperature, and rainfall data taken near a tiltmeter site were used in a study of the numerical relation between these phenomena and the recorded tilt response. A least-squares shaping and predictive error filter approach was used. The relations were ranked in part according to the root mean square (r.m.s.) error of fit across the entire sample space. The tilt data with an annual range of tilt of approximately 10 microradians were fitted to the combined weather data of temperature and rainfall with a 0.75-microradian r.m.s. error. The best fit of earthquakes to these same tilt data is the subclass of events with magnitude (M) > 2.5 within 30 kilometers of the tilt site. The filter that mapped earthquakes to tilt yielded a 1.03-microradian r.m.s. error. The most unusual tilt anomaly over the entire 2-year period has the best fit of rainfall to the data for any single month of the entire data set. This unusual anomaly was the basis of an erroneously predicted earthquake (M ∼ 5). These data indicate that if there are premonitory earthquake signals, they are buried in local meteorlogical noise. Separating an earthquake anomaly from the response to surface phenomena becomes more difficult as the earthquake anomaly lead time approaches the rise time of the soil to weather and seasonal variations.
Relative Fecundity and Parental Effort in Communally Nesting Anis,
Crotophaga sulcirostris
Authors: Vehrencamp Sandra L.
Published: October 2006

The contribution of eggs to the communal clutch by females of the group and the genetic contribution by males of the group are significantly skewed. The amount of parental care performed by each bird is correlated with relative egg ownership for both sexes.
Combustion of Several 2,4,5-Trichlorophenoxy Compounds: Formation of 2,3,7,8-Tetrachlorodibenzo-
p
-dioxin
Authors: Stehl R. H. , Lamparski L. L.
Published: October 2006

Grass and paper coated with several compounds containing the 2,4,5-trichlorophenoxy moiety have been subjected to combustion. By using compounds that had been purified to achieve low background amounts of 2,3,7,8-tetrachlorodibenzo-
p
-dioxin (TCDD) together with an efficient cleanup and analysis of the residue, it was possible to detect as little as 0.001 microgram of TCDD in the combustion products of 0.5 gram of the 2,4,5-trichlorophenoxy material. Small self-supported fires converted about 10
-6
of the 2,4,5-trichlorophenoxy material to TCDD.
Sympatric Speciation Based on Allelic Changes at Three Loci: Evidence from Natural Populations in Two Habitats
Authors: Tauber Catherine A. , Tauber Maurice J.
Published: October 2006

Allelic changes at three loci largely explain
Chrysopa downesi's
sympatric speciation from a
Chrysopa carnea
-like ancestor. Disruptive selection first produced a stable polymorphism based on a single pair of alleles that adapted individuals to two habitats, and second, it established seasonal asynchrony in reproduction through allelic substitutions at two loci.
Arthropod Invasion of Land During Late Silurian and Devonian Times
Authors: Størmer Leif
Published: October 2006

Fossil floras and faunas of a Lower Devonian black shale from Alken, Germany, include aquatic, amphibious, and terrestrial forms. The presence of these forms suggests conditions in favor of an invasion of the land. Various arthropod adaptations to terrestrial life are present, including the development of a preoral cavity.
Unusual Topogenic Sequence Directs Prion Protein Biogenesis
Authors: Lopez Charles D. , Yost C. Spencer , Prusiner Stanley B. , Myers Richard M. , Lingappa Vishwanath R.
Published: October 2006

Biosynthetic studies of the prion protein (PrP) have shown that two forms of different topology can be generated from the same pool of nascent chains in cell-free translation systems supplemented with microsomal membranes. A transmembrane form is the predominant product generated in wheat germ (WG) extracts, whereas a completely translocated (secretory) form is the major product synthesized in rabbit reticulocyte lysates (RRL). An unusual topogenic sequence within PrP is now shown to direct this system-dependent difference. The actions of this topogenic sequence were independent of on-going translation and could be conferred to heterologous proteins by the engineering of a discrete set of codons. System-dependent topology conferred by addition of RRL to WG translation products suggests that this sequence interacts with one or more cytosolic factors.
Imitation of Facial and Manual Gestures by Human Neonates
Authors: Meltzoff Andrew N. , Moore M. Keith
Published: October 2006

Infants between 12 and 21 days of age can imitate both facial and manual gestures; this behavior cannot be explained in terms of either conditioning or innate releasing mechanisms. Such imitation implies that human neonates can equate their own unseen behaviors with gestures they see others perform.
Ocean Wave Patterns Under Hurricane Gloria: Observation with an Airborne Synthetic-Aperture Radar
Authors: Elachi C. , Thompson T. W. , King D.
Published: October 2006

Surface imagery of ocean waves under Hurricane Gloria (September 1976) has been obtained with an airborne synthetic-aperture imaging radar. Observations were obtained over most of the area within a radius of 150 kilometers around the center of the eye. These direct observations made it possible to derive the wave patterns in the region around a hurricane eye.
Hormonal Inhibition of Feeding and Death in
Octopus
: Control by Optic Gland Secretion
Authors: Wodinsky Jerome
Published: October 2006

Female
Octopus hummelincki
lays eggs, broods them, reduces its food intake, and dies after the young hatch. Removal of both optic glands after spawning results in cessation of broodiness, resumption of feeding, increased growth, and greatly extended life-span. Optic gland secretions may cause death of most cephalopods and may function to control population size.
Carbon Monoxide on Jupiter and Implications for Atmospheric Convection
Authors: Prinn Ronald G. , Barshay Stephen S.
Published: October 2006

A study of the equilibrium and disequilibrium thermochemistry of the recently discovered carbon monoxide on Jupiter suggests that the presence of this gas in the visible atmosphere is a direct result of very rapid upward mixing from levels in the deep atmosphere where the temperature is about 1100°K and where carbon monoxide is thermodynamically much more stable. As a consequence the observed carbon monoxide mixing ratio is a sensitive function of the vertical eddy mixing coefficient. We infer a value for this latter coefficient which is about three to four orders of magnitude greater than that in the earth's troposphere. This result directly supports existing structural and dynamical theories implying very rapid convection in the deep Jovian atmosphere, driven by an internal heat source.
Pierce's Disease of Grapevines: Isolation of the Causal Bacterium
Authors: Davis Michael J. , Purcell Alex H. , Thomson Sherman V.
Published: October 2006

A Gram-negative, rod-shaped bacterium has been consistently isolated from grapevines with Pierce's disease. Grapevines inoculated with the bacterium developed Pierce's disease, and the bacterium was reisolated from the plants. The bacterium was serologically and ultrastructurally indistinguishable from the one in naturally infected plants, and also indistinguishable from a bacterium isolated from almonds with almond leaf scorch disease.
Liquid Fuels from Coal: From R & D to an Industry
Authors: Swabb L. E.
Published: October 2006

On the basis of current U.S. oil imports, room now exists for a U.S. coal liquids industry. Unfortunately, technology is not available which can produce coal liquids at a price competitive with imported oil. Direct liquefaction technology is under development, but the prospects are that the technology will not be economic at the time the pioneer commercial plant should be constructed to provide the foundation for a possible coal liquids industry in the 1990's. Government support of coal liquefaction R & D has created the conditions that make possible the development of the technology, and probably government incentives for pioneer plants will be needed. With the proper incentives pioneer plants will lead to lower costs, and this, plus rising prices, will create the conditions necessary to develop a multiplant industry.
Excess Helium-4 in Teggau Lake: Possibilities for a Uranium Ore Body
Authors: Torgersen Thomas , Clarke W. B.
Published: October 2006

Excess
4
He (more than five times the solubility) has been measured in Teggau Lake in northwestern Ontario. A model suggests that an adjacent mass of greater than 10
4
kilograms of uranium is responsible for the observed
4
He excess. The area is favorable for pegmatitic uranium deposits, and the release of trapped
4
He from uraninite dikes larger than 30 cubic meters (1 percent U
3
O
8
) provides the best explanation for the excess
4
He in the lake.
"Wolf-in-Sheep's-Clothing" Strategy of a Predaceous Insect Larva
Authors: Eisner Thomas , Hicks Karen , Eisner Maria , Robson Douglas S.
Published: October 2006

The larva of the green lacewing
Chrysopa slossonae
lives in colonies of the wooly alder aphid
Prociphilus tesselatus
upon which it feeds. It disguises itself as its prey by plucking some of the waxy "wool" from the bodies of the aphids and applying this material to its own back. The investiture protects it from assault by the ants that ordinarily "shepherd" the aphids. Larvae artificially denuded are seized by the ants and removed from the aphid colonies. A larva requires on the average less than 20 minutes to coat itself with wax. A hungry denuded larva gives the coating procedure about the same behavioral priority as feeding.
Epidermal Patterns of the Lemma in Some Fossil and Living Grasses and Their Phylogenetic Significance
Authors: Thomasson Joseph R.
Published: October 2006

Morphological study of fossil grass anthoecia of
Berriochloa
and
Nassella
collected from Miocene-Pliocene strata in Kansas has revealed well-preserved epidermal structure. This seems to be the first micromorphological information known from fossil grass floral bracts. The epidermal pattern on the lemma in the fossils and their living counterparts are evidence in support of the view that the North American species of
Stipa
of the section
Hesperostipa
Elias and species of
Piptochaetium
have a common ancestry in
Berriochloa
, and that species of both taxa have been distinct from species of the
Nassella
,
Oryzopsis
, and other
Stipa
since at least the Miocene or Pliocene.
Normal Metallic Point Contacts
Authors: Jansen A. G. M. , Mueller F. M. , Wyder P.
Published: October 2006

The measured voltage derivative of the nonlinear resistance of tiny point contacts can be separated into a phonon-emission effect (α
2
F
) and an analytic functional form (background effect). The α
2
F
's show structure coincident with bulk phonon densities of states. Values of the integral of 2 α
2
F
/ω are closely related to literature values. The background effect is related to the impurity concentration of the materials.
Handedness in Duckweed: Double Flowering Fronds Produce Right- and Left-Handed Lineages
Authors: Doss Robert P.
Published: October 2006

Frond lineages of
Lemna perpusilla
Torr. (strain 6746) show handedness with respect to frond emergence sequence and flowering that is related to the pocket of origin on a double flowering mother frond. Flower position is a fundamental manifestation of frond asymmetry.
The Hobbling of Coal: Policy and Regulatory Uncertainties
Authors: Gordon Richard L.
Published: October 2006

The inevitable by-product of societal concern over the side effects of coal production and use is greater than recognized difficulties to meet coal production goals. Thus, society faces the need to make trade-offs it is not adequately anticipating. The primary influences have come from air pollution regulation dealing with sulfur oxides; regulations in this realm were strengthened in 1977. Questions exist about the ability to meet these requirements and about whether tighter controls will be imposed on other pollutants. Problems also exist on the production side—labor unrest, stripmine reclamation requirements, and delays in leasing federally owned coal.
Forest Floor Leaching: Contributions from Mineral, Organic, and Carbonic Acids in New Hampshire Subalpine Forests
Authors: Cronan Christopher S. , Reiners William A. , Reynolds Robert C. , Lang Gerald E.
Published: October 2006

Analyses of soil water and groundwater samples from a high-elevation coniferous ecosystem in New England indicate that sulfate anions supply 76 percent of the electrical charge balance in the leaching solution. This result implies that atmospheric inputs of sulfuric acid provide the dominant source of both H
+
for cation replacement and mobile anions for cation transport in subalpine soils of the northeastern region affected by acid precipitation. In soils of relatively unpolluted regions, carbonic and organic acids dominate the leaching processes.
The Three-Dimensional Structure of Canine Parvovirus and Its Functional Implications
Authors: Tsao Jun , Chapman Michael S. , Agbandje Mavis , Keller Walter , Smith Kathy , Wu Hao , Luo Ming , Smith Thomas J. , Rossmann Michael G. , Compans Richard W. , Parrish Colin R.
Published: October 2006

The three-dimensional atomic structure of a single-stranded DNA virus has been determined. Infectious virions of canine parvovirus contain 60 protein subunits that are predominantly VP-2. The central structural motif of VP-2 has the same topology (an eight-stranded antiparallel β barrel) as has been found in many other icosahedral viruses but represents only about one-third of the capsid protein. There is a 22 angstrom (Å) long protrusion on the threefold axes, a 15 Å deep canyon circulating about each of the five cylindrical structures at the fivefold axes, and a 15 Å deep depression at the twofold axes. By analogy with rhinoviruses, the canyon may be the site of receptor attachment. Residues related to the antigenic properties of the virus are found on the threefold protrusions. Some of the amino termini of VP-2 run to the exterior in full but not empty virions, which is consistent with the observation that some VP-2 polypeptides in full particles can be cleaved by trypsin. Eleven nucleotides are seen in each of 60 symmetry-related pockets on the interior surface of the capsid and together account for 13 percent of the genome.
Isopod and Insect Root Borers May Benefit Florida Mangroves
Authors: Simberloff Daniel , Brown Becky Jean , Lowrie Stuart
Published: October 2006

Far from threatening the persistence and geographic extent of red mangrove (
Rhizophora mangle
) in Florida, wood-boring marine isopods may aid the plant to survive wave action by initiating branching of aerial prop roots. Evidence for a recent, sudden increase in density or range of one such isopod,
Sphaeroma terebrans
, is anecdotal and weak. Insect damage to mangrove aerial roots even before they descend to the water is at least as great as that wrought by isopods and also causes root branching. Aerial and submarine damage combine to stimulate root initiation so that, for every root produced aerially by the tree, at least 1.4 roots reach the substrate. Similar responses to herbivory, which have been reported for other plants, suggest that herbivores may both benefit and harm plants, and that their impact may be more difficult to assess in specific instances than has been realized.
Complex Iron Smelting and Prehistoric Culture in Tanzania
Authors: Schmidt Peter , Avery Donald H.
Published: October 2006

Western scientists and students of history have long explained the iron bloomery process by evidence available from European archeology. Ethnographic, technological, and archeological research into the technological life of the Haya of northwestern Tanzania show that these people and their forebears 1500 to 2000 years ago practiced a highly advanced iron smelting technology based on preheating principles and, as a result, produced carbon steel. This sophisticated technology may have evolved as an adaptation to overexploited forest resources. These discoveries are significant for the history of Africa and the history of metallurgy.
Writing, Dictating, and Speaking Letters
Authors: Gould John D. , Boies Stephen J.
Published: October 2006

It is commonly assumed that dictation requires a long time to learn, but authors eventually dictate much faster than they write. Performance results now show that novice dictators can learn in a few hours to dictate with the speed and quality with which they write. However, they do not
think
they perform this well. Dictators with years of experience are from 0 to 25 percent faster than novices, depending upon the complexity of the letters. Planning time is about two-thirds of composition time, regardless of the method of composition.