bluuebunny/crossref_metadata_2025 huggingface dataset:
Planarian peptidylglycine‐hydroxylating monooxygenase, a neuropeptide processing enzyme, colocalizes with cytochrome b561 along the central nervous system
Authors: Asada Akikazu , Orii Hidefumi , Watanabe Kenji , Tsubaki Motonari
Published: October 2006

Planarians are one of the simplest animal groups with a central nervous system. Their primitive central nervous system produces large quantities of a variety of neuropeptides, of which many are amidated at their C terminus. In vertebrates, peptide amidation is catalyzed by two enzymes [peptidylglycine α‐hydroxylating monooxygenase (PHM) and peptidyl‐α‐hydroxylglycine α‐amidating lyase] acting sequentially. In mammals, both enzymatic activities are contained within a single protein that is encoded by a single gene. By utilizing PCR with degenerate oligonucleotides derived from conserved regions of PHM, we succeeded in cloning a full‐length cDNA encoding planarian PHM. The deduced amino acid sequence showed full conservation of five His residues and one Met residue, which bind two Cu atoms that are essential for the activity of PHM. Northern blot analysis confirmed the expression of a PHM mRNA of the expected size. Distribution of the mRNA was analyzed by in situ hybridization, showing specific expression in neurons with two morphologically distinct structures, a pair of the ventral nerve cords and the brain. The distribution of PHM was very similar to that of cytochrome b561. This indicates that the ascorbate‐related electron transfer system operates in the planarian central nervous system to support the PHM activity and that it predates the emergence of Plathelminthes in the evolutionary history.
Religion in the Dead Sea Scrolls
Authors: Jassen Alex P.
Published: October 2006

The present study is intended as a synthesis of the current state of research on religion in the Qumran community as articulated in the Dead Sea Scrolls. We treat here religion both in thought and in practice. The former refers to the theological belief system of the Qumran community: God, dualism and predestination and eschatology, messianism, and resurrection; the latter indicates the way that the religious ideals of the Qumran community were actualized in daily life: formation of Jewish law, temple, sacrifice, and prayer, and ritual and purity. Our intention is to present the critical issues (and texts) as they relate to each of these subjects and the various scholarly models associated with their study.
Medicine and Religion in Ancient Egypt
Authors: Zucconi Laura M.
Published: October 2006

Seminal works on ancient Egyptian medicine tend to treat the field as distinct from religious practices, often fixating on the medical papyri as exemplifying either rational or magical treatments. Refocusing the study towards the ancient Egyptian conceptions of physiology and disease etiology shows that their medical practices integrated religious concepts such asmaat(balance) andheka(power). Therapeutic measures and titles for healers,swnw,wabpriest, andsau, further underscored the physical interchange between the mortal and divine worlds for the ancient Egyptians.
The Holocaust: Remembrances, Reflections, Revisions
Authors: Whitfield Stephen J.
Published: October 2006

The moral abyss that about four decades ago came to be called the Holocaust has generated a vast literature seeking to probe the meaning of that catastrophe. A forthcoming volume to which eminent scholars have contributed from such fields as philosophy, history, and literary studies offers an opportunity to consider the current status of reflections on the Holocaust. Based in England and Israel as well as the United States, these particular academics demonstrate how inescapable their topic remains, how elusive is the struggle to decipher what may resist any satisfying explanation – or representation.
Canaanite Religion
Authors: Noll K. L.
Published: October 2006

“Canaanite religion” is a controversial term because the Bible and some religious scholars distinguish between Canaanite and Israelite religions. However, biblical and archaeological data suggest that Israelite religion was one local variety of the larger, regional Canaanite religion. Canaanite religion is the religion of all peoples living on the eastern Mediterranean seaboard prior to the Common Era. The gods and the myths in this region display some stable characteristics, yet evolved new details and changing divine relationships throughout ancient times. At the center of Canaanite religion was royal concern for religious and political legitimacy and the imposition of a divinely ordained legal structure, as well as peasant emphasis on fertility of the crops, flocks, and humans.
Characterization and restoration of altered inhibitory and excitatory control of micturition reflex in experimental autoimmune encephalomyelitis in rats
Authors: Vignes Jean‐Rodolphe , Deloire Mathilde S. A. , Petry Klaus G. , Nagy Frédéric
Published: October 2006

Multiple sclerosis (MS) is characterized by inflammatory lesions throughout the central nervous system. Spinal cord inflammation correlates with many neurological defecits. Most MS patients suffer from micturition dysfunction with urinary incontinence and difficulty in emptying the bladder. In experimental autoimmune encephalomyelitis (EAE) induced in female Lewis rats, a model of MS, we investigated at distinct clinical severity scores the micturition reflex by cystometrograms. All rats presenting symptomatic EAE suffered from micturition reflex alterations with either detrusor areflexia or hyperactivity. During pre‐symptomatic EAE, a majority of rats presented with detrusor areflexia, whereas at onset of clinical EAE, detrusor hyperactivity was predominant. During progression of EAE, detrusor areflexia and hyperactivity were equally expressed. Bladder hyperactivity was suppressed by activation of glycine and GABA receptors in the lumbosacral spinal cord with an order of potency: glycine > GABAB > GABAA. Detrusor areflexia was transformed into detrusor hyperactivity by blocking glycine and GABA receptors. Spinalization abolished bladder activity in rats presenting detrusor hyperactivity and failed to induce activity in detrusor areflexia. Altogether, the results reveal an exaggerated descending excitatory control in both detrusor reflex alterations. In detrusor areflexia, a strong segmental inhibition dominates this excitatory control. As in treatment of MS, electrical stimulation of sacral roots reduced detrusor hyperactivity in EAE. Blockade of glycine receptors in the lumbosacral spinal cord suppressed the stimulation‐induced inhibitory effect. Our data help to better understand bladder dysfunction and treatment mechanisms to suppress detrusor hyperactivity in MS.
Cerebral blood flow and oxygenation in ovine fetus: responses to superimposed hypoxia at both low and high altitude
Authors: Peňa Jorge Pereyra , Tomimatsu Takuji , Hatran Douglas P. , McGill Lisa L. , Longo Lawrence D.
Published: October 2006

For the fetus, although the roles of arterial blood gases are recognized to be critical in the regulation of cerebral blood flow (CBF) and cerebral oxygenation, the relation of CBF, cortical tissuePO2(tPO2), sagittal sinusPO2, and related indices of cerebral oxygenation to arterial blood gases are not well defined. This is particularly true for that fetus subjected to long‐term hypoxia (LTH). In an effort to elucidate these interrelations, we tested the hypothesis that in the fetus acclimatized to high altitude, cerebral oxygenation is not compromised relative to that at low altitude. By use of a laser Doppler flowmeter with a fluorescent O2probe, in near‐term fetal sheep at low altitude (n= 8) and those acclimatized to high altitude hypoxia (3801 m for 90 ± 5 days;n= 6), we measured laser Doppler CBF (LD‐CBF),tPO2, and related variables in response to 40 min superimposed hypoxia. At both altitudes, fetal LD‐CBF, cerebral O2delivery,tPO2, and several other variables including sagittal sinusPO2, correlated highly with arterialPO2(Pa,O2). In response to superimposed hypoxia (Pa,O2= 11 ± 1 Torr), LD‐CBF was significantly blunted at high altitude, as compared with that at low altitude. In the two altitude groups fetal cerebral oxygenation was similar under both control conditions and with superimposed hypoxia, corticaltPO2decreasing from 8 ± 1 and 6 ± 1 Torr, respectively, to 2 ± 1 Torr. Also, for these conditions sagittal sinusPO2and [HbO2] values were similar. In response to superimposed hypoxia, cerebral metabolic rate for O2decreased ∼50% in each group (P< 0.05). For both the fetus at low altitude and that acclimatized to high altitude LTH, we present the first dose–response data on the relation of LD‐CBF, corticaltPO2, and sagittal sinus blood gas values toPa,O2. In addition, despite differences in several variables, the fetus at high altitude showed evidence of successful acclimatization, supporting the hypothesis that such fetuses demonstrate no compromise in cerebral oxygenation.
Neuronal two‐pore‐domain potassium channels and their regulation by G protein‐coupled receptors
Authors: Mathie Alistair
Published: October 2006

Leak potassium currents in the nervous system are often carried through two‐pore‐domain potassium (K2P) channels. These channels are regulated by a number of different G protein‐coupled receptor (GPCR) pathways. The TASK subfamily of K2P channels are inhibited following activation of the G protein Gαq. The mechanism(s) that transduce this inhibition have yet to be established but there is evidence to support a role of phosphatidylinositol 4,5‐bisphosphate (PIP2) hydrolysis products, depletion of PIP2 itself from the membrane, or a direct action of activated Gαq on TASK channels. It seems possible that more than one pathway may act in parallel to transduce inhibition. By contrast, TRESK channels are stimulated following activation of Gαq. This is due to stimulation of the protein phosphatase, calcineurin, which dephosphorylates TRESK channels and enhances their activity. TREK channels are the most widely regulated of the K2P channel subfamilies being inhibited following activation of Gαq and Gαs but enhanced following activation of Gαi. The multiple pathways activated and the apparent promiscuous coupling of at least some K2P channel types to different G protein regulatory pathways suggests that the excitability of neurons that express K2P channels will be profoundly sensitive to variations in GPCR activity.
Deep Mixing of
3
He: Reconciling Big Bang and Stellar Nucleosynthesis
Authors: Eggleton Peter P. , Dearborn David S. P. , Lattanzio John C.
Published: October 2006

Low-mass stars, ∼1 to 2 solar masses, near the Main Sequence are efficient at producing the helium isotope
3
He, which they mix into the convective envelope on the giant branch and should distribute into the Galaxy by way of envelope loss. This process is so efficient that it is difficult to reconcile the low observed cosmic abundance of
3
He with the predictions of both stellar and Big Bang nucleosynthesis. Here we find, by modeling a red giant with a fully three-dimensional hydrodynamic code and a full nucleosynthetic network, that mixing arises in the supposedly stable and radiative zone between the hydrogen-burning shell and the base of the convective envelope. This mixing is due to Rayleigh-Taylor instability within a zone just above the hydrogen-burning shell, where a nuclear reaction lowers the mean molecular weight slightly. Thus, we are able to remove the threat that
3
He production in low-mass stars poses to the Big Bang nucleosynthesis of
3
He.
Dynamical Superconducting Order Parameter Domains in Sr
2
RuO
4
Authors: Kidwingira Francoise , Strand J. D. , Van Harlingen D. J. , Maeno Yoshiteru
Published: October 2006

We present direct evidence for complex p-wave order parameter symmetry and the presence of dynamical chiral order parameter domains of the form
p

x

±
ip

y

in the ruthenate superconductor Sr
2
RuO
4
. The domain structure creates differences in the magnetic field modulation of the critical current of Josephson junctions fabricated on orthogonal faces of Sr
2
RuO
4
single crystals. Transitions between the chiral states of a domain or the motion of domain walls separating them generates telegraph noise in the critical current as a function of magnetic field or time and is responsible for hysteresis observed in field sweeps of the critical current. The presence of such domains confirms the p-wave triplet spin and complex (broken time-reversal symmetry) nature of the superconducting pairing state in Sr
2
RuO
4
.
Ice, Quakes, and a Wobble Shake San Francisco
Authors: Kerr Richard A.
Published: October 2006

The fall meeting of the American Geophysical Union (AGU) in San Francisco last month was bumped to the Moscone Center while the Civic Auditorium, its venue in past years, was being reinforced against earthquakes. And that may have been fitting, given the meeting's focus on sudden events in Earth history: the first moments of fault rupture, repeated outbursts of icebergs during the last ice age, and a shift in the seasons in the middle of this century.
Atomic Resolution of the Silicon (111)-(7×7) Surface by Atomic Force Microscopy
Authors: Giessibl Franz J.
Published: October 2006

Achieving high resolution under ultrahigh-vacuum conditions with the force microscope can be difficult for reactive surfaces, where the interaction forces between the tip and the samples can be relatively large. A force detection scheme that makes use of a modified cantilever beam and senses the force gradient through frequency modulation is described. The reconstructed silicon (111)-(7×7) surface was imaged in a noncontact mode by force microscopy with atomic resolution (6 angstroms lateral, 0.1 angstrom vertical).
Atomic-Scale Images of the Growth Surface of Ca

1–
x

Sr

x

CuO
2
Thin Films
Authors: Koguchi Kazumasa , Matsumoto Takuya , Kawai Tomoji
Published: October 2006

The surface microstructure of
c
-axis (Ca,Sr)CuO
2
thin films, grown by laser molecular beam epitaxy on SrTiO
3
(001) substrates, was studied by ultrahigh-vacuum scanning tunneling microscopy (STM). Images were obtained for codeposited Ca

1–
x

Sr

x

CuO
2
thin films, which show a layered-type growth mode. The surfaces consist of atomically flat terraces separated by steps that are one unit cell high. A pronounced dependence of the growth mechanism on the Sr/Ca ratio of the films was observed. Atomic resolution STM images of the CuO
2
sheets in the
ab
plane show a square lattice with an in-plane spacing of 4 angstroms; the lattice contains different concentrations of point defects, depending on the polarity of the sample-tip bias.
Use of a Sound-Based Vibratome by Leaf-Cutting Ants
Authors: Tautz Jürgen , Roces Flavio , Hölldobler Bert
Published: October 2006

Leaf-cutting ants harvest fresh vegetation that they then use as food for symbiotic fungi. When cutting leaf fragments, the ants produce high-frequency vibrations with a specialized organ located on the gaster. This stridulation behavior is synchronized with movements of the mandible, generating complex vibrations of the mandibles. The high vibrational acceleration of the mandible (up to three times the gravitational force at peak acceleration at about 1000 hertz) appears to stiffen the material to be cut. An identical effect is achieved when soft material is sectioned with a vibratome. This hypothesis is supported by experiments simulating the cutting process with vibrating isolated mandibles: When tender leaves were cut, the vibration of the mandible reduced force fluctuations and thus permitted a smoother cut to be made.
Response of High-Rise and Base-Isolated Buildings to a Hypothetical
M
w
7.0 Blind Thrust Earthquake
Authors: Heaton Thomas H. , Hall John F. , Wald David J. , Halling Marvin W.
Published: October 2006

High-rise flexible-frame buildings are commonly considered to be resistant to shaking from the largest earthquakes. In addition, base isolation has become increasingly popular for critical buildings that should still function after an earthquake. How will these two types of buildings perform if a large earthquake occurs beneath a metropolitan area? To answer this question, we simulated the near-source ground motions of a
M
w
7.0 thrust earthquake and then mathematically modeled the response of a 20-story steel-frame building and a 3-story base-isolated building. The synthesized ground motions were characterized by large displacement pulses (up to 2 meters) and large ground velocities. These ground motions caused large deformation and possible collapse of the frame building, and they required exceptional measures in the design of the base-isolated building if it was to remain functional.
Earthquakes in the Los Angeles Metropolitan Region: A Possible Fractal Distribution of Rupture Size
Authors: Hough S. E.
Published: October 2006

Although there is debate on the maximum size of earthquake that is possible on any of several known fault systems in the greater Los Angeles metropolitan region, it is reasonable to assume that the distribution of earthquakes will follow a fractal distribution of rupture areas. For this assumption and an overall slip-rate for the region of approximately 1 centimeter per year, roughly one magnitude 7.4 to 7.5 event is expected to occur every 245 to 325 years. A model in which the earthquake distribution is fractal predicts that, additionally, there should be approximately six events in the range of magnitude 6.6 in this same span of time, a higher rate than has occurred in the historic record.
Mutation Rates and Dominance Levels of Genes Affecting Total Fitness in Two Angiosperm Species
Authors: Johnston Mark O. , Schoen Daniel J.
Published: October 2006

Theories about the evolution of sex and the effects of inbreeding depend on knowledge of the mutation rate and dominance level of deleterious alleles affecting total fitness. In two species of largely self-fertilizing annual plants, minimal estimates of such mutation rates were found to be 0.24 to 0.87 per sporophyte genome per generation, but confidence intervals exceeded 1.0 in each of the four populations. Dominance levels were near zero in one species and intermediate (0.28 to 0.35) in the other. These results suggest that the detrimental effects of inbreeding are a result of new partially recessive mutations rather than overdominance.
Inhibition of Host Gene Expression Associated with Plant Virus Replication
Authors: Wang Daowen , Maule Andrew J.
Published: October 2006

Pea seed-borne mosaic virus (PSbMV) RNA replication in pea cotyledonary tissues was restricted largely to a zone of cells close to the infection front. In situ hybridization probes representing nine genes from two pathways of metabolism failed to detect RNA transcripts within this zone, although transcripts were found in similar amounts in tissues on either side of the zone. Thus, in common with some animal viruses, PSbMV transiently suppresses the expression of host genes. Host protein accumulation was also affected. These observations provide insights into virus-plant interactions and symptom expression.
Proximity of Jupiter-Like Planets to Low-Mass Stars
Authors: Boss Alan P.
Published: October 2006

The sensitivities of astrometric and radial velocity searches for extrasolar planets are strongly dependent on planetary masses and orbits. Because most nearby stars are less massive than the sun, the first detection is likely to be of a Jupiter-mass planet orbiting a low-mass star, with a possible theoretical expectation being that Jupiter-like planets will be found much closer [inside the Earth-sun separation of 1 astronomical unit (AU)] to these low-luminosity stars than Jupiter is to the sun (5.2 AU). However, radiative hydrodynamic models of protoplanetary disks around low-mass stars (of 0.1 to 1 solar mass) show that Jupiter-like planets should form at distances (approximately 4 to 5 AU) that are only weakly dependent on the stellar mass.
The Structure of Confined Oxygen in Silica Xerogels
Authors: Schirato B. S. , Fang M. P. , Sokol P. E. , Komarneni S.
Published: October 2006

The microscopic structure of oxygen confined in silica xerogels has been studied as a
function of temperature. In large pores, a crystalline solid forms with a structure
consistent with that of the bulk. The size of the crystallites is much larger than the
pore size, indicating that cooperative effects among pores are important in freezing. As
the pore size is decreased, a crossover occurs where solidification results in an
amorphous phase in the pores. The resulting amorphous phase is solid but is less ordered
than the liquid phase.
Clustering and Periodic Recurrence of Microearthquakes on the San Andreas Fault at Parkfield, California
Authors: Nadeau R. M. , Foxall W. , McEvilly T. V.
Published: October 2006

The San Andreas fault at Parkfield, California, apparently late in an interval between repeating magnitude 6 earthquakes, is yielding to tectonic loading partly by seismic slip concentrated in a relatively sparse distribution of small clusters (<20-meter radius) of microearthquakes. Within these clusters, which account for 63% of the earthquakes in a 1987-92 study interval, virtually identical small earthquakes occurred with a regularity that can be described by the statistical model used previously in forecasting large characteristic earthquakes. Sympathetic occurrence of microearthquakes in nearby clusters was observed within a range of about 200 meters at communication speeds of 10 to 100 centimeters per second. The rate of earthquake occurrence, particularly at depth, increased significantly during the study period, but the fraction of earthquakes that were cluster members decreased.
Stress-induced Vortex Line Helixing Avalanches in the Plastic Flow of a Smectic A Liquid Crystal
Authors: Herke Richard A. , Clark Noel A. , Handschy Mark A.
Published: October 2006

Dynamic surface force measurements of the response of a smectic A to layer normal stress exhibited time dependence for topological events in which single smectic layers were added or removed. Single layer-sized jumps in sample thickness had a rapid component of duration of ∼1 second that produced most of the change in separation, but that was heralded by a slow precursor acceleration in separation, which began up to a few hundred seconds before. This avalanche-like dynamic signature is consistent with a relaxation mechanism based on the Glaberson-Clem-Bourdon instability of vortex lines (screw dislocations) in the smectic order parameter.
Solid-State Defect Mechanism in Vanadyl Pyrophosphate Catalysts: Implications for Selective Oxidation
Authors: Gai Pratibha L. , Kourtakis K.
Published: October 2006

High-resolution and in situ electron microscopy of vanadyl pyrophosphate catalysts reacted in alkane (
n
-butane) and other reducing environments have shown evidence for surface structure modifications accompanied by two sets of symmetry-related extended defects. Defect analysis reveals that the defects are formed by pure (glide) shear mechanism. The defect mechanism suggests the presence of basal (coplanar) anion vacancies, associated with Lewis acid centers, at oxygen sites linking corner-sharing phosphorus tetrahedra and vanadyl octahedra in the active plane. These in-plane defect sites may be key to the activation of the alkane, especially in the dehydrogenation.
Mantle Convection with Plates and Mobile, Faulted Plate Margins
Authors: Zhong Shijie , Gurnis Michael
Published: October 2006

A finite-element formulation of faults has been incorporated into time-dependent models of mantle convection with realistic rheology, continents, and phase changes. Realistic tectonic plates naturally form with self-consistent coupling between plate and mantle dynamics. After the initiation of subduction, trenches rapidly roll back with subducted slabs temporarily laid out along the base of the transition zone. After the slabs have penetrated into the lower mantle, the velocity of trench migration decreases markedly. The inhibition of slab penetration into the lower mantle by the 670-kilometer phase change is greatly reduced in these models as compared to models without tectonic plates.
Galaxies, Human Eyes, and Artificial Neural Networks
Authors: Lahav O. , Naim A. , Buta R. J. , Corwin H. G. , de Vaucouleurs G. , Dressler A. , Huchra J. P. , van den Bergh S. , Raychaudhury S. , Sodré L. , Storrie-Lombardi M. C.
Published: October 2006

The quantitative morphological classification of galaxies is important for understanding
the origin of type frequency and correlations with environment. However, galaxy
morphological classification is still mainly done visually by dedicated individuals, in
the spirit of Hubble's original scheme and its modifications. The rapid increase in data
on galaxy images at low and high redshift calls for a re-examination of the classification
schemes and for automatic methods. Here are shown results from a systematic comparison of
the dispersion among human experts classifying a uniformly selected sample of more than
800 digitized galaxy images. These galaxy images were then classified by six of the
authors independently. The human classifications are compared with each other and with an
automatic classification by an artificial neural network, which replicates the
classification by a human expert to the same degree of agreement as that between two human
experts.
Shifting Dominance Within a Montane Vegetation Community: Results of a Climate-Warming Experiment
Authors: Harte John , Shaw Rebecca
Published: October 2006

In experimentally heated plots that each span a soil moisture gradient in a Rocky Mountain meadow, aboveground biomass of
Artemisia tridentata
(a sagebrush) increased in the drier habitat and that of
Pentaphylloides floribunda
(a shrub cinquefoil) increased in the wetter habitat relative to control plots. In contrast, aboveground forb biomass decreased in the wet and dry habitats of the heated plots. These results, combined with evidence for enhanced sagebrush seedling establishment rates in the heated plots, suggest that the increased warming expected under an atmosphere with a concentration of carbon dioxide twice that of pre-industrial levels could change the dominant vegetation of a widespread meadow habitat.
Resonant Tunneling in the Quantum Hall Regime: Measurement of Fractional Charge
Authors: Goldman V. J. , Su B.
Published: October 2006

In experiments on resonant tunneling through a "quantum antidot" (a potential hill) in the quantum Hall (QH) regime, periodic conductance peaks were observed as a function of both magnetic field and back gate voltage. A combination of the two periods constitutes a measurement of the charge of the tunneling particles and implies that charge deficiency on the antidot is quantized in units of the charge of quasi-particles of the surrounding QH condensate. The experimentally determined value of the electron charge e is 1.57 × 10
–19
coulomb = (0.98 ± 0.03)
e
for the states ν = 1 and ν = 2 of the integer QH effect, and the quasi-particle charge is 5.20 × 10
–20
coulomb = (0.325 ± 0.01)
e
for the state ν = 1/3 of the fractional QH effect.
A Conducting Polymer Film Stronger Than Aluminum
Authors: Shi Gaoquan , Jin Shi , Xue Gi , Li Cun
Published: October 2006

Polythiophene (Pth) was electrochemically deposited onto stainless steel substrate from freshly distilled boron fluoride-ethyl ether containing 10 millimoles of thiophene per liter. The free-standing Pth film obtained at an applied potential of 1.3 volts (versus Ag/AgCl) had a conductivity of 48.7 siemens per centimeter. Its tensile strength (1200 to 1300 kilograms per square centimeter) was greater than that of aluminium (1000 to 1100 kilograms per square centimeter). This Pth film behaves like a metal sheet and can be easily cut into various structures with a knife or a pair of scissors.
The Reaction of CIONO
2
with Submicrometer Sulfuric Acid Aerosol
Authors: Hanson D. R. , Lovejoy E. R.
Published: October 2006

The measured reaction probability, γ, for the reaction of chlorine nitrate (CIONO
2
) with 60 percent (by weight) sulfuric acid aerosol increases monotonically with particle size at 250 kelvin. The reacto-diffusive length (ℓ, the effective liquid depth over which reaction occurs) derived from these experiments is 0.037 ± 0.007 micrometer (95 percent confidence level for precision). The reaction probability for the reaction of CIONO
2
with 60 percent sulfuric acid aerosol doped with ∼7 × 10
–4
M hydrochloric acid at 250 kelvin is larger by about a factor of 4 than in the absence of hydrochloric acid and varies less with particle size (ℓ = 0.009 ± 0.005 micrometer). These results provide a test of the theory for gas-particle reactions and further insight into the reactivity of atmospheric aerosol.
Rapid Deformation of the South Flank of Kilauea Volcano, Hawaii
Authors: Owen Susan , Segall Paul , Freymueller Jeff , Mikijus Asta , Denlinger Roger , Árnadóttir Thora , Sako Maurice , Bürgmann Roland
Published: October 2006

The south flank of Kilauea volcano has experienced two large [magnitude (M) 7.2 andM6.1] earthquakes in the past two decades. Global Positioning System measurements conducted between 1990 and 1993 reveal seaward displacements of Kilauea's central south flank at rates of up to about 10 centimeters per year. In contrast, the northern side of the volcano and the distal ends of the south flank did not displace significantly. The observations can be explained by slip on a low-angle fault beneath the south flank combined with dilation deep within Kilauea's rift system, both at rates of at least 15 centimeters per year.
Multilayer White Light-Emitting Organic Electroluminescent Device
Authors: Kido Junji , Kimura Masato , Nagai Katsutoshi
Published: October 2006

Organic electroluminescent devices are light-emitting diodes in which the active materials consist entirely of organic materials. Here, the fabrication of a white light-emitting organic electroluminescent device made from vacuum-deposited organic thin films is reported. In this device, three emitter layers with different carrier transport properties, each emitting blue, green, or red light, are used to generate white light. Bright white light, over 2000 candelas per square meter, nearly as bright as a fluorescent lamp, was successfully obtained at low drive voltages such as 15 to 16 volts. The applications of such a device include paper-thin light sources, which are particularly useful for places that require lightweight illumination devices, such as in aircraft and space shuttles. Other uses are a backlight for liquid crystal display as well as full color displays, achieved by combining the emitters with micropatterned color filters.
Isotopic Tracking of Change in Diet and Habitat Use in African Elephants
Authors: Koch Paul L. , Heisinger Jennifer , Moss Cynthia , Carlson Richard W. , Fogel Marilyn L. , Behrensmeyer Anna K.
Published: October 2006

The carbon, nitrogen, and strontium isotope compositions of elephants in Amboseli Park, Kenya, were measured to examine changes in diet and habitat use since the 1960s. Carbon isotope ratios, which reflect the photosynthetic pathway of food plants, record a shift in diet from trees and shrubs to grass. Strontium isotope ratios, which reflect the geologic age of bedrock, document the concentration of elephants within the park. The high isotopic variability produced by behavioral and ecological shifts, if it is representative of other East African elephant populations, may complicate the use of isotopes as indicators of the source region of ivory.
Structural Features That Stabilize Halophilic Malate Dehydrogenase from an Archaebacterium
Authors: Dym O. , Mevarech M. , Sussman J. L.
Published: October 2006

The high-resolution structure of halophilic malate dehydrogenase (hMDH) from the archaebacterium
Haloarcula marismortui
was determined by x-ray crystallography. Comparison of the three-dimensional structures of hMDH and its nonhalophilic congeners reveals structural features that may promote the stability of hMDH at high salt concentrations. These features include an excess of acidic over basic residues distributed on the enzyme surface and more salt bridges present in hMDH compared with its nonhalophilic counterparts. Other features that contribute to the stabilization of thermophilic lactate dehydrogenase and thermophilic MDH—the incorporation of alanine into α helices and the introduction of negatively charged amino acids near their amino termini, both of which stabilize the α helix as a result of interaction with the positive part of the α-helix dipole—also were observed in hMDH.
Micrometer- and Nanometer-Sized Polymeric Light-Emitting Diodes
Authors: Granström Magnus , Berggren Magnus , Inganäs Olle
Published: October 2006

A method for the fabrication of micrometer- and submicrometer-sized polymeric light-emitting diodes is presented. Such diodes have a variety of applications. Light sources of dimensions around 100 nanometers are required for subwavelength, near-field optical microscopy. Another possible application is patterning on the micrometer and nanometer scale. The diodes have been made in the form of a sandwich structure, with the conductive polymer poly(3,4-ethylene-dioxythiophene) polymerized in the pores of commercially available microfiltration membranes defining the hole-injecting contacts, poly[3-(4-octylphenyl)-2,2′-bithiophene] as the light-emitting layer, and a thin film of calcium-aluminum as the electron injector.
Influence of Lunar Phase on Daily Global Temperatures
Authors: Balling Robert C. , Cerveny Randall S.
Published: October 2006

A newly available data set of daily satellite-derived, lower-tropospheric global temperature anomalies provides an opportunity to assess the influence of lunar phase on planetary temperature. These results reveal a statistically significant 0.02 K modulation between new moon and full moon, with the warmest daily global temperatures over a synodic month coincident with the occurrence of the full moon. Spectral analysis of the daily temperature record confirms the presence of a periodicity that matches the lunar synodic (29.53-day) cycle. The precision of the satellite-based daily temperature record allows verification that the moon exerts a discernible influence on the short-term, global temperature record.
Formation of Glasses from Liquids and Biopolymers
Authors: Angell C. A.
Published: October 2006

Glasses can be formed by many routes. In some cases, distinct polyamorphic forms are found. The normal mode of glass formation is cooling of a viscous liquid. Liquid behavior during cooling is classified between "strong" and "fragile," and the three canonical characteristics of relaxing liquids are correlated through the fragility. Strong liquids become fragile liquids on compression. In some cases, such conversions occur during cooling by a weak first-order transition. This behavior can be related to the polymorphism in a glass state through a recent simple modification of the van der Waals model for tetrahedrally bonded liquids. The sudden loss of some liquid degrees of freedom through such first-order transitions is suggestive of the polyamorphic transition between native and denatured hydrated proteins, which can be interpreted as single-chain glass-forming polymers plasticized by water and cross-linked by hydrogen bonds. The onset of a sharp change in
d
〈
r
2
〉/
dT
(〈
r
2
〉 is the Debye-Waller factor and
T
is temperature) in proteins, which is controversially indentified with the glass transition in liquids, is shown to be general for glass formers and observable in computer simulations of strong and fragile ionic liquids, where it proves to be close to the experimental glass transition temperature. The latter may originate in strong anharmonicity in modes ("bosons"), which permits the system to access multiple minima of its configuration space. These modes, the Kauzmann temperature
T
K
, and the fragility of the liquid, may thus be connected.
A Topographic View of Supercooled Liquids and Glass Formation
Authors: Stillinger Frank H.
Published: October 2006

Various static and dynamic phenomena displayed by glass-forming liquids, particularly those near the so-called "fragile" limit, emerge as manifestations of the multidimensional complex topography of the collective potential energy function. These include non-Arrhenius viscosity and relaxation times, bifurcation between the α- and β-relaxation processes, and a breakdown of the Stokes-Einstein relation for self-diffusion. This multidimensional viewpoint also produces an extension of the venerable Lindemann melting criterion and provides a critical evaluation of the popular "ideal glass state" concept.
The Seasons, Global Temperature, and Precession
Authors: Thomson David J.
Published: October 2006

Analysis of instrumental temperature records beginning in 1659 shows that in much of the world the dominant frequency of the seasons is one cycle per anomalistic year (the time from perihelion to perihelion, 365.25964 days), not one cycle per tropical year (the time from equinox to equinox, 365.24220 days), and that the timing of the annual temperature cycle is controlled by perihelion. The assumption that the seasons were timed by the equinoxes has caused many statistical analyses of climate data to be badly biased. Coherence between changes in the amplitude of the annual cycle and those in the average temperature show that between 1854 and 1922 there were small temperature variations, probably of solar origin. Since 1922, the phase of the Northern Hemisphere coherence between these quantities switched from 0° to 180° and implies that solar variability cannot be the sole cause of the increasing temperature over the last century. About 1940, the phase patterns of the previous 300 years began to change and now appear to be changing at an unprecedented rate. The average change in phase is now coherent with the logarithm of atmospheric CO2concentration.
Herbivory in Asymbiotic Soft Corals
Authors: Fabricius Katharina E. , Benayahu Yehuda , Genin Amatzia
Published: October 2006

A zooxanthellae-free soft coral from the Red Sea feeds almost exclusively on phytoplankton, a mode of nutrition so far unknown for corals. Herbivory was also found in three other azooxanthellate soft corals. In tropical oligotrophic waters, phytoplankton biomass density may be an order of magnitude higher than that of zooplankton. Use of this resource allows these azooxanthellate cnidarians to be highly productive in flow-exposed oligotrophic reef waters.
Spin Crossover in a Catenane Supramolecular System
Authors: Real José Antonio , Andrés Enrique , Muñoz M. Carmen , Julve Miguel , Granier Thierry , Bousseksou Azzedine , Varret François
Published: October 2006

The compound [Fe(tvp)
2
(NCS)
2
] ⋅ CH
3
OH, where tvp is 1,2-di-(4-pyridyl)-ethylene, has been synthesized and characterized by x-ray single-crystal diffraction. It consists of two perpendicular, two-dimensional networks organized in parallel stacks of sheets made up of edge-shared [Fe(II)]
4
rhombuses. The fully interlocked networks define large square channels in the [001] direction. Variable-temperature magnetic susceptibility measurements and Mössbauer studies reveal that this compound shows low-spin to high-spin crossover behavior in the temperature range from 100 to 250 kelvin. The combined structural and magnetic characterization of this kind of compound is fundamental for the interpretation of the mechanism leading to the spin crossover, which is important in the development of electronic devices such as molecular switches.
Imaging the Condensation and Evaporation of Molecularly Thin Films of Water with Nanometer Resolution
Authors: Hu J. , Xiao X. -D. , Ogletree D. F. , Salmeron M.
Published: October 2006

The polarization force between an electrically charged atomic force microscope tip and a substrate has been used to follow the processes of condensation and evaporation of a monolayer of water on mica at room temperature. Condensation proceeds in two distinct structural phases. Up to about 25 percent humidity, the water film grows by forming two-dimensional clusters of less than a few 1000 angstroms in diameter. Above about 25 percent humidity, a second phase grows, forming large two-dimensional islands with geometrical shapes in epitaxial relation with the underlaying mica lattice. The growth of this second water phase is completed when the humidity reaches about 45 percent. The reverse process of evaporation has also been imaged.
Testing Cosmogonic Models with Gravitational Lensing
Authors: Wambsganss Joachim , Cen Renyue , Ostriker Jeremiah P. , Turner Edwin L.
Published: October 2006

Gravitational lensing provides a strict test of cosmogonic models because it is directly sensitive to mass inhomogeneities. Detailed numerical propagation of light rays through a universe that has a distribution of inhomogeneities derived from the standard CDM (cold dark matter) scenario, with the aid of massive, fully nonlinear computer simulations, was used to test the model. It predicts that more widely split quasar images should have been seen than were actually found. These and other inconsistencies rule out the Cosmic Background Explorer (COBE)-normalized CDM model with density parameter ω = 1 and the Hubble constant (
H
o
) = 50 kilometers second
–1
megaparsec
–1
; but variants of this model might be constructed, which could pass the stringent tests provided by strong gravitational lensing.
Imaging the Pore Structure of Geomaterials
Authors: Fredrich J. T. , Menéndez B. , Wong T. -F.
Published: October 2006

Laser scanning confocal microscopy can be used to image the pore structure of geologic materials in three dimensions at a resolution of 200 nanometers. The technique involves impregnation of the void space with an epoxy doped with a fluorochrome whose fluorescent wavelength matches the excitation wavelength. Optical sections with a thickness of less than 1 micrometer can be sliced from thick polished sections and combined to produce three-dimensional reconstructions. Application of the technique to rocks with porosities from 1 to 20 percent reveals the geometric complexity of the pore space. The technique can also be applied to other brittle solids such as ceramics.
A Modular Steel Freeway Bridge: Design Concept and Earthquake Resistance
Authors: Wattenburg W. H. , McCallen D. B. , Murray R. C.
Published: October 2006

A modular multilane steel freeway bridge has been constructed from surplus railroad flatcar decks. It can be erected on-site in a few days' time. It has been built and static-load tested for emergency freeway bridge repair. This inexpensive modular bridge may also have broad application around the world for low-cost bridges in areas where funds are limited. On the basis of static-load testing performed by the California Department of Transportation and computer dynamic analysis, this simple modular-design concept has the potential of providing a strong bridge that can withstand the severe aftershocks expected immediately after a major earthquake.
Continent-Ocean Chemical Heterogeneity in the Mantle Based on Seismic Tomography
Authors: Forte Alessandro M. , Dziewonski Adam M. , O'Connell Richard J.
Published: October 2006

Seismic models of global-scale lateral heterogeneity in the mantle show systematic differences below continents and oceans that are too large to be purely thermal in origin. An inversion of the geoid, based on a seismic model that includes viscous flow in the mantle, indicates that the differences beneath continents and oceans can be accounted for by differences in composition in the upper mantle superposed on mantle-wide thermal heterogeneities. The net continent-ocean density differences, integrated over depth, are small and cause only a low flux of mass and heat across the asthenosphere and mantle transition zone.
The Collapse of Free Polymer Chains in a Network
Authors: Briber Robert M. , Liu Xiaodu , Bauer Barry J.
Published: October 2006

The conformation of linear polymer chains trapped in a matrix of cross-linked polymer has been measured by neutron scattering. Three regimes were found depending on the length of the linear chain,
N

l

, with respect to the mesh size of the network,
N
c
. When
N
c
>
N

l

, the radius of gyration,
R
g
, of the linear chain is the same as that observed in the uncrosslinked melt. When
N
c
<
N

l

,
R
g
shrinks according to the scaling relation
R
g
–1
∼
N
c
–1
that has been predicted for isolated polymer chains trapped in a field of random obstacles. When
N
c
<<
N

l

the linear chains are observed to segregate.
High-Temperature Molecular Magnets Based on Cyanovanadate Building Blocks: Spontaneous Magnetization at 230 K
Authors: Entley William R. , Girolami Gregory S.
Published: October 2006

The molecular-based magnetic materials Cs
2
Mn
II
[V
II
(CN)
6
] (1) and (Et
4
N)
0.5
Mn
1.25
- [V(CN)
5
]⋅ ⋅2H
2
O (2) (where Et is ethyl) were prepared by the addition of manganese(II) triflate to aqueous solutions of the hexacyanovanadate(II) ion at 0°C. Whereas 1 crystallizes in a face-centered cubic lattice, 2 crystallizes in a noncubic space group. The cesium salt (1) has features characteristic of a three-dimensional ferrimagnet with a Néel transition at 125 kelvin. The tetraethylammonium salt (2) also behaves as a three-dimensional ferrimagnet with a Néel temperature of 230 kelvin; only two other molecular magnets have higher magnetic ordering temperatures. Saturation magnetization measurements indicate that in both compounds the V
II
and high-spin Mn
II
centers are antiferromagnetically coupled. Both 1 and 2 exhibit hysteresis loops characteristic of soft magnets below their magnetic phase-transition temperatures. The high magnetic ordering temperatures of these cyano-bridged solids confirm that the incorporation of early transition elements into the lattice promotes stronger magnetic coupling by enhancing the backbonding into the cyanide π* orbitals.
Discovery of an Unmelted H-Chondrite Inclusion in an Iron Meteorite
Authors: Casanova Ignacio , Graf Thomas , Marti Kurt
Published: October 2006

The link between H chondrites and silicate inclusions in group IIE iron meteorites has long been suspected, but direct evidence for a common parentage has remained elusive. The discovery of an unmelted chondritic inclusion in the Techado iron meteorite sheds light on the genetic relation between these two groups, providing clues on the origin of chondritic materials as inclusions in iron meteorites. It is proposed that the complex IIE iron meteorite breccias formed by collisions with several different bodies, followed by deep burial of metal and silicate fragments in the asteroidal megaregolith.
Computation Beyond the Turing Limit
Authors: Siegelmann Hava T.
Published: October 2006

Extensive efforts have been made to prove the Church-Turing thesis, which suggests that all realizable dynamical and physical systems cannot be more powerful than classical models of computation. A simply described but highly chaotic dynamical system called the analog shift map is presented here, which has computational power beyond the Turing limit (super-Turing); it computes exactly like neural networks and analog machines. This dynamical system is conjectured to describe natural physical phenomena.
Modification of Plant Lipid Synthesis
Authors: Töpfer Reinhard , Martini Norbert , Schell Jeff
Published: October 2006

Genetic engineering of new storage oils and fats has produced oil crop plants with fatty acid compositions unattainable by plant breeding alone. The combination of classical breeding methods with molecular techniques provides new ways for designing oils for food and nonfood uses. Alterations in the position and number of double bonds, variation in fatty acid chain length, and the introduction of desired functional groups have already been achieved in model systems. Short-term prospects include crops such as rapeseed or soybean engineered to have greater than 70 to 80 percent medium-chain fatty acids by content, greater than 90 percent oleic acid, and high erucic acid content, and engineered to form ricinoleic acid in seed storage tissues.