cssi/SciSciGPT-SciSciNet huggingface dataset:
Statics of a "self-organized" percolation model.

A stochastic forest-fire'' model is considered. Sites are filled individually at a constant mean rate; also, sparks'' are dropped at a small rate [ital k], and instantaneously burn up the entire cluster they hit. I find [ital nontrivial] critical exponents in the self-organized critical limit [ital k][r arrow]0, contrary to earlier results of Drossel and Schwabl. Spatial correlation functions and a site occupancy correlation exponent are measured for the first time. Scaling relations, derived by analogy to uncorrelated percolation, are used extensively as numerical checks. Hyperscaling is violated in this system.
Novel marine sponge alkaloids 3. β-carbolinium salts from Fascaplysinopsis reticulata

The pursuit of bioactive substances from the massive Indo-Pacific sponge Fascaplysnopsis reticulata has yielded unusual salts 1 – 3. Each has a sesterterpenoid anion associated with an alkaloid cation, and a new substituted β-carboline arrangement 6 is present in salts 1 and 2.
Novel Copolymers of Styrene and Alkyl and Alkoxy Ring‐Trisubstituted Methyl 2‐Cyano‐3‐phenyl‐2‐propenoates

Electrophilic trisubstituted ethylene monomers, akyl and alkoxy ring‐trisubstituted methyl 2‐cyano‐3‐phenyl‐2‐propenoates, RC6H2CH[dbnd]C(CN)CO2CH3, (where R is 2,3‐dimethyl‐4‐methoxy, 2,5‐dimethyl‐4‐methoxy‐, 2,3,4‐trimethoxy‐, 2,4,5‐trimethoxy, 2,4,6‐trimethoxy, and 2,4‐dimethoxy‐3‐methyl), were synthesized by the piperidine catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and methyl cyanoacetate, and characterized by CHN elemental analysis, IR, 1H‐ and 13C‐NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, 1H and 13C NMR, GPC, DSC, and TGA. High Tg of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene mon...
The role of atypical semantic activation and stress in odd speech: implications for individuals with psychometrically defined schizotypy.

Abstract Background Odd speech is a cardinal symptom of schizophrenia; however, little is known about the mechanisms that lead to this construct in schizophrenia or schizotypy, the estimated 10% of the population who exhibit traits presumed to reflect genetic liability to schizophrenia. The lack of research concerning specific mechanisms of odd speech represents an important knowledge gap. Here, our primary aim was to examine how atypical semantic activation (ASA) and stress are related to odd speech in individuals with psychometrically-defined schizotypy. Methods We employed highly sensitive laboratory procedures to test whether significant differences in ASA exist between psychometric schizotypy (n = 45) and non-psychometric schizotypy (n = 26) groups. We also examined odd speech across four conditions that varied according to valence (pleasant, unpleasant) and arousal (high, low) and analyzed whether ASA mediates odd speech in schizotypy. Results The psychometric schizotypy group demonstrated significantly increased ASA, in the large effect size range. They also demonstrated a significant increase in one odd speech condition and a trend level group by arousal interaction was observed. Our hypothesis that ASA mediates odd speech in schizotypy was not supported. Conclusions Individuals with psychometric schizotypy exhibit semantic activation that is similar to patients with schizophrenia, albeit in a milder form. This study also provides evidence that ASA is a potential endophenotype of schizophrenia. Future studies should further explore properties of odd speech and ASA. Suggested avenues include cognitive deficits, particularly working memory, exploring underlying mechanisms, and examining how these constructs affect individuals across the schizophrenia-spectrum.
Adult neurogenesis: VCAM stems the tide.

In this issue of Cell Stem Cell, Kokovay et al. uncover that VCAM1 expression in neural stem cells regulates adult neurogenesis. Cerebrospinal fluid-borne IL-1β upregulates VCAM1 expression, which in turn regulates the architecture of the stem cell niche, redox homeostasis, and neurogenesis.
Exchange Markets: A Welfare Comparison of Market Maker and Walrasian Systems

This paper compares the social welfare of a simple economy with asymmetric information under two different exchange market structures, Walrasian and the monopolistic, price-setting schemes. It is found that the relative efficiency depends on the nature of uncertainties in the economy. For some environments, the price-setting allocation with a market maker Pareto dominates the rational expectations equilibrium allocation in a competitive market. This finding provides a justification for the existence of the market maker system, which is the predominant institutional arrangement in many exchange markets.
Pyroclastic rocks and calderas associated with strongly peralkaline magmatism

Strongly peralkaline volcanic complexes tend to be shieldlike due to coalescence of low-viscosity lavas from numerous vent areas and blanketing by pyroclastic flows and falls. Dense welding and rheomorphism commonly mask the nature of pyroclastic units; welded pumice falls are common. Relatively low eruptive columns produce poorly sorted pumice falls that are difficult to distinguish from topography mantling pyroclastic flows. Welded fall deposits are characterized by multiple, fine-scale, welding reversals, welding zones that correspond with stratification, and by flattening of fiamme parallel to underlying slopes, whereas welded topography-mantling ignimbrites may have fine-grained basal layers, lithic lenses, imbricate fiamme, and variations in crystal content and fiamme size with topographic position. Calderas are relatively small, typically 3–9 km in diameter, with little evidence for single-stage subsidence in excess of a few hundred meters. Many strongly peralkaline volcanic centers show evidence of two or more nested calderas, and partial reactivation of older ring fractures is common. Replenishment of magma reservoirs beneath calderas can promote dilatant reactivation of older subsidence structures, resulting in multicyclic collapses that reuse these structures. In several centers, the caldera-forming unit is zoned from pantellerite to more crystal-rich trachyte. Following collapse, trachyte lavas commonly erupt from a central vent on the caldera floor, building a cone that nearly fills the caldera. Reestablishment of isostatic equilibrium may be accomplished both by eruption of these lavas and by flow of trachytic and more-mafic magma into the root zone beneath the volcano. Resurgent doming sensu strictu has not been documented in strongly peralkaline systems; at Pantelleria and Mount Suswa, however, the central portions of the cauldron blocks were uplifted and tilted. Magma reservoirs that feed explosive eruptions generally are shallow, as indicated by pyroclastic units that contain lithic fragments of the volcanic edifice (commonly including cognate syenite) but lack subjacent crustal lithologies. In addition, the overwhelming predominance of alkali feldspar as a phenocryst phase and the scarcity of quartz are consistent with pantellerite liquidus relations only at pressures <100 MPa. Pantellerite and trachyte shields may represent the mature stage of continental rift volcanism; once the flux of mantle-derived magmas has been sufficient to generate a large mass of felsic liquid that can act as a density filter, mafic magmas rarely reach the surface.
Aerosol source plume physical characteristics from space-based multiangle imaging

Models that assess aerosol effects on regional air quality and global climate parameterize aerosol sources in terms of amount, type, and injection height. The multiangle imaging spectroradiometer (MISR) aboard NASA's Terra satellite retrieves total column aerosol optical thickness (AOT), and aerosol type over cloud-free land and water. A stereo-matching algorithm automatically retrieves reflecting-layer altitude wherever clouds or aerosol plumes have discernable spatial contrast, with about 500-m accuracy, at 1.1-km horizontal resolution. Near-source biomass burning smoke, volcanic effluent, and desert dust plumes are observed routinely, providing information about aerosol amount, particle type, and injection height useful for modeling applications. Compared to background aerosols, the plumes sampled have higher AOT, contain particles having expected differences in Angstrom exponent, size, single-scattering albedo, and for volcanic plume and dust cloud cases, particle shape. As basic thermodynamics predicts, thin aerosol plumes lifted only by regional winds or less intense heat sources are confined to the boundary layer. However, when sources have sufficient buoyancy, the representative plumes studied tend to concentrate within discrete, high-elevation layers of local stability; the aerosol is not uniformly distributed up to a peak altitude, as is sometimes assumed in modeling. MISR-derived plume heights, along with meteorological profile data from other sources, make it possible to relate radiant energy flux observed by the moderate resolution imaging spectroradiometer (MODIS), also aboard the Terra spacecraft, to convective heat flux that plays a major role in buoyant plume dynamics. A MISR climatology of plume behavior based on these results is being developed.
Lapazia obscura: a New Armored Scale Insect from Texas (Homoptera: Coccoidea: Diaspididae)

Lapazia obscura, a new species of armored scale insect from Texas, is described and illustrated, and a diagnosis is provided to distinguish it from L. obtecta, the generic type. Prior to this paper, the genus Lapazia was mono basic.
Direct 4-D PET List Mode Parametric Reconstruction With a Novel EM Algorithm

The production of images of kinetic parameters is often the ultimate goal of positron emission tomography (PET) imaging. The indirect method of PET parametric imaging, also called the frame-based method (FM), is performed by fitting the time-activity curve (TAC) for each voxel with an appropriate compartment model after image reconstruction. The indirect method is simple and easily implemented, however, it usually leads to some loss of accuracy or precision, due to the use of two separate steps. This paper presents a direct 4-D method for producing 3-D images of kinetic parameters from list mode PET data. In this application, the TAC for each voxel is described by a one-tissue compartment model (1T). Extending previous EM algorithms, a new spatiotemporal complete data space was introduced to optimize the maximum likelihood function. This leads to a straightforward closed-form parametric image update equation. This method was implemented by extending the current list mode platform MOLAR to produce a parametric algorithm PMOLAR-1T. Using an ordered subset approach, qualitative and quantitative evaluations were performed using 2-D (x, t) and 4-D (x, y, z, t) simulated list mode data based on brain receptor tracers and also with a human brain study. Comparisons with the indirect method showed that the proposed direct method can lead to accurate estimation of the parametric image values with reduced variance, especially at low count levels. In the 2-D test, the direct method showed similar bias to the frame-based method but with variance reduction of 23%-60%. In the 4-D test, bias values of both methods were no more than 4% and the direct method had lower variability (coefficient of variation reduction of 0%-64% compared to the frame-based method) at the normal count level. The direct method had a larger reduction in variability (27%-81%) and lower bias (1%-5% for 4-D and 1%-19% for FM) at low count levels. The results in the human brain study are similar with PMOLAR-1T showing lower noise than FM.
Regulated In Situ Generation of Molecular Ions or Protonated Molecules under Atmospheric-Pressure Helium-Plasma-Ionization Mass Spectrometric Conditions

In an enclosed atmospheric-pressure helium-plasma ionization (HePI) source engulfed with dehumidified ambient gases, molecular cations are generated from compounds such as toluene, bromobenzene, and iodobenzene. Evidently, the ionization is effected by a direct Penning mechanism attributable to interactions of the gas-phase analyte with metastable helium atoms. It is widely known that secondary ions generated from ambient gases also play an important role in the overall ionization process. For example, when the ambient gases bear even traces of moisture, the analytes are ionized by proton transfer reactions with gaseous H3O+. In this study, we demonstrate how a controlled variation of experimental conditions can manipulate the abundance of molecular ions and protonated molecules in a HePI source.
RF atmospheric plasma systems for deposition of nanostructures

Summary form only given. Two types of RF atmospheric plasma systems were used for deposition of nanostructures on polymer substrates. Both systems consist of the quartz tubes equipped by the RF antennas at frequencies 13.56 MHz and/or 27.12 MHz and a Laval nozzle at the end. The nozzle provides simultaneously nucleation of the nanoparticles in the fly, accelerates them in the direction of the substrate and keeps the nanoparticle flow at the outlet cold enough to protect the polymer substrate from thermal damages. Both systems have a two-stage design where the first stage serves as a generator of the droplets of the melted precursor as well as a trigger and sustainer of the ICP plasma in the second stage that is in reality a RF plasma chemical reactor with feeding of processing gases. In the first type a DC plasma torch with hollow hafnium cathode for an axial feeding of the precursors with feeding rate up to 1 kg/h was used. The droplets undergo a series of plasmochemical reactions in the RF reactor, where all of them are converted in an axial vapor flow. To increase the dwelling time the reactor consists of 12" long quartz tube with 4.5" OD and is supplied by two RF coils. The bottom coil is connected to the 13.56 MHz generator and the top to the 27.12 MHz one. The second type served for deposition of ultra-high purity materials. The DC plasma torch was replaced by a commercial ICP-OES torch that provides relatively low velocity of the flow and the droplets have enough dwelling time in the second stage to be evaporated. Therefore, the length of the RF reactor was reduced twice. The second stage has one saddle-like RF antenna that concentrates all RF power in the gap between its right and left parts. Each part serves also as a capacitor's plate and creates first a capacitively coupled discharge before the development of an ICP one. The speed of the vapor flow at the exit of the reactor is relatively low. So, the conditions for nucleation of nanoparticles in the Laval nozzle are completely different comparing with the DC-RF-RF plasma system. The use of Laval nozzle with special profile increases the flexibility of the control of ICP plasma spraying for producing of nanostructured coatings under atmospheric conditions. Estimation of the ICP plasma parameters and the cooling time in the Laval nozzle are presented
Model for the growth of plasma deposited A-SI:H and related materials

A model based on hydrogen equilibration relates the growth of a-Si:H alloys to their electronic properties. The alloys are distinguished by the strength of the hydrogen bonding. The model explains why a-Si:C:H, a-Si:N:H and a-Si:O:H, have a large disorder broadening of the band tails and silicon dangling bonds, while a-Si:Ge:H has Ge dangling bonds and low disorder broadening. Possible growth conditions to improve the alloys are suggested.
Antiestrogen action: Differential nuclear retention and extractability of the estrogen receptor

Since there is a much longer uterine nuclear retention of the U-11, 100A (antiestrogen) receptor complex (UARC) than of the estradiol receptor complex (ERC) at 4-12 hrs after injection, experiments were designed to determine if there is a difference between the relative nuclear affinities for the two RCs as determined by extraction with various ionic strength mediums. Although the UARC was retained longer in the nuclear fraction in vivo, the UARC was completely extractable with 0.3M KCl or 50mM spermine, whereas the ERC demonstrates a salt-resistant form. This suggests that the ERC is more tightly bound to nuclear components through this salt-resistant form of the receptor. In addition, various intercalating agents were used to distinguish the different nuclear chromatin DNA sites where the UARC and ERC may be binding. With actinomycin D (50 uM) more ERC than UARC was retained in the nuclear fraction. However, with ethidium bromide (100uM) less ERC than UARC was retained. Also, the ERC selectively released by ethidium bromide is precisely that fraction not released by salt. These results indicate that the UARC and ERC bind to different chromatin loci.
Betatron phase and coupling correction at the Cornell Electron/Positron Storage Ring

The presence of quadrupole errors in a storage ring will lead to errors in the Twiss parameters and/or errors in the horizontal-vertical coupling. This in turn can lead to degradation of machine performance, such as a decrease in the luminosity. At the Cornell Electron/Positron Storage Ring, the measurement of the betatron phase along with the horizontal-vertical coupling has led to the ability to locate the position of any quadrupole errors and to calculate its strength. This is analogous to using orbit data to locate the source of a kick. Once the source of the error is known, steps can be taken to remove it or to nullify its effect.
Development of Safe Cooling Schedules for Structural Clay Products

A method is described whereby safe cooling schedules for structural clay products are developed, based on a criterion for thermal failure. Resistance to thermal failure may be indicated by the following equation: Resistance =MR a/Ea, where MR is the modulus of rupture, E is the modulus of elasticity, a is the thermal diffusivity, and a is the coefficient of linear thermal contraction. The modulus of rupture, modulus of elasticity, linear thermal contraction, and relative thermal diffusivity of three commercial bodies were measured in the temperature range 1600°F. to room temperature. Using the experimental values, relative cooling schedules are developed in terms of ware temperature versus dimensionless time, the total time for cooling being a function of size and shape. The order of importance of the physical properties is discussed with respect to cooling schedules and it is concluded that the coefficient of linear thermal contraction has the greatest effect. The mechanisms acting in clay bodies during cooling are discussed and the idea of quartz separation is presented. The hysteresis of the modulus of elasticity and coefficient of thermal expansion while heating and cooling is correlated with quartz separation and the literature is cited to support the idea. Some tests are described to show that rebonding of the quartz occurs on reheating to sufficiently high temperatures.
The optical evaluation of atmospheric dustfall

Abstract Present methods for assessing atmospheric dustfall measure the weight of settled particles, but the nuisance produced by dustfall is a visual one which is associated with particle projected area. A rapid, simple experimental technique is proposed to evaluate the projected area of dustfall collected on microscope slides during sampling periods as short as 4 hr. The method is based on exposing the slide to evaporated aluminum in a vacuum chamber, followed by removal of adhering particles to produce an opaque slide with transparent apertures formed during evaporation. The area of the apertures is determined on an optical bench by measuring light transmission through the treated slide. The experimental procedures and apparatus are discussed in detail.
Time-dependent scar enhancement in magnetic resonance imaging of the postoperative lumbar spine

Magnetic resonance imaging (MRI) has become a principal modality in the evaluation of the postoperative lumbar spine. Gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) can often facilitate differentiation of scar from recurrent disc herniation according to established criteria. Scar has been believed to enhance predictably. We reviewed the contrast-enhanced MR scans of 44 patients who were examined for recurrent back pain following disc surgery and attempted to assess the enhancement characteristics of scar as a function of the time interval between initial surgery and the imaging study. In 44 patients, scar was believed to be present at 32 of 49 disc levels. The degree of enhancement was related to the postoperative interval; those studies performed no later than 9 months after surgery tended to exhibit the greatest degree of enhancement. Surgical confirmation of these MRI findings was available in 12 patients. In patients examined long after surgery, scar enhancement may be less intense than in those examined shortly after surgery, or even nonexistent. This temporal factor should be considered when using contrast material to differentiate scar from recurrent disc herniation in postoperative examinations of the lumbar spine.
Accelerator mass spectrometry of actinides

Accelerator mass spectrometry (AMS) is a sensitive and robust technique typically applied to the quantification of long-lived radioisotopes in samples too small to be decay-counted. AMS is characterized by a high rejection of interferences and a low susceptibility to matrix components, which reduce the demands on sample preparation chemistry. At Lawrence Livermore National Laboratory (LLNL), Center for Accelerator Mass Spectrometry (CAMS), we have developed an AMS capability for the measurement of actinide concentrations and isotopic ratios. To date, this capability has been primarily devoted to the measurement of 239Pu and 240Pu in bioassay and environmental samples including soils, sediments, waters, and human urine. For these analyses, a known amount of 242Pu is added to the samples as a reference isotope for normalization. Measurements of standard and intercomparison samples have shown that quantification is accurate and precise from at least 106 to 1011 atoms/sample. Recently, the ratios of 240Pu, 241Pu, 242Pu, and +Pu to intrinsic 239Pu have been successfully measured in soil samples from nuclear test sites. In addition, initial measurements of U and Np isotopes have yielded results consistent with the Pu measurements with respect to sensitivity, accuracy, precision, and linear range.
Laplace Transform of Spherical Bessel Functions

We provide a simple analytic formula in terms of elementary functions for the Laplace transform l(p) of the spherical Bessel function than that appearing in the literature, and we show that any such integral transform is a polynomial of order l in the variable p with constant coefficients for the first l - 1 powers, and with an inverse tangent function of argument 1/p as the coefficient of the power l. We apply this formula for the Laplace transform of the memory function related to the Langevin equation in a one-dimensional Debye model.
Multicultural Education and Head Start: Empowering Young Children

The multicultural movement has influenced education in the United States and several other countries over the past 3 decades, as described in “History and Trends of Multicultural Education” in this...
High-Throughput Selectivity Assays for Small-Molecule Inhibitors of β-Catenin/T-Cell Factor Protein-Protein Interactions.

Two homogeneous high-throughput assays, AlphaScreen and fluorescence polarization, were established to quantify inhibitor selectivity between different protein–protein complexes. As a first case study, they have been successfully applied to the key protein–protein interactions in the downstream sites of the canonical Wnt signaling pathway. The aberrant formation of the β-catenin/T-cell factor (Tcf) complex is the major driving force for many cancers and fibroses. Crystallographic and biochemical studies reveal that the binding modes of Tcf, E-cadherin, and adenomatous polyposis coli (APC) to β-catenin are identical and mutually exclusive. In the present study, two highly sensitive and robust assays were established to quantitatively evaluate inhibitor selectivity between β-catenin/Tcf, β-catenin/E-cadherin, and β-catenin/APC interactions. A pilot screen demonstrated the feasibility of the assays and yielded four hits for the disruption of β-catenin/Tcf interactions. A potent and dual-selective β-catenin/T...
Live attenuated varicella vaccine: Evidence that the virus is attenuated and the importance of skin lesions in transmission of varicella-zoster virus

To examine whether the live varicella vaccine virus is attenuated, we analyzed varicella vaccine-induced contact cases of clinical chickenpox in healthy siblings of immunized children with leukemia. A rash developed approximately 1 month later in 156 children with leukemia who had been vaccinated. Vaccine-type virus was isolated from 25 of these children. Of 88 known susceptible healthy siblings who were exposed to a vaccinee with a rash and from whom follow-up information was available, there was evidence of infection in 15 (17%). Of 15 siblings with seroconversion, 11 (73%) also acquired a mild rash with an average of 38 lesions and no accompanying systemic symptoms. Vaccine-type virus was isolated from four of the contact siblings. Tertiary transmission was documented once. Contact siblings with seroconversion were protected during future household exposure to chickenpox, which occurred in four instances. There was a direct relationship between transmission from vaccinees to varicella-susceptible close contacts and the presence and number of skin lesions in children with leukemia after vaccination. We conclude that in the transmission of varicella, the virus probably originates from skin lesions of infected persons and reaches the respiratory tract of those with secondary cases by the airborne route. On the basis of the mildness of the contact illness, the higher-than-normal rate of subclinical primary infection with varicella-zoster virus in contacts, and the lower-than-normal rate of spread of the vaccine virus to susceptible children in the household, we further conclude that the vaccine virus is attenuated. There was no evidence of reversion of the vaccine virus to virulence.
Elastic Properties of Flux-Line Arrays in High Transition Temperature Superconductors Probed by Two-Sided Decoration

The elastic constants of magnetic flux-line lattices in copper oxide superconductors have remained uncharacterized despite their essential role in determining important phenomena such as melting. Here the absolute values of the elastic moduli of flux-line arrays have been probed by correlating the positions of individual flux lines emerging from opposite sides of Bi 2 Sr 2 CaCu 2 O 8 (BSCCO) superconductors. These experiments demonstrate that the compressional and shear moduli of the flux-line lattice are three orders of magnitude smaller than the values predicted by standard models. The origin of these changes in the moduli and the general applicability of this approach to other materials are discussed. In addition, there is a remarkable correspondence between the excitations of the flux-line arrays and those of superfluid helium.
Ultrafine Iron Powder as an Oxygen Adsorbent for Argon Purification. Activation of Iron by Milling

Ultrafine reactive iron powder was prepared by a high-performance milling procedure using commercially available iron powder. The milled iron material was found to have very high affinity to oxygen. The activated powder reacted at very mild conditions even with traces of oxygen in argon. The deactivated iron material can be easily reactivated by reduction in a stream of diluted hydrogen. The activation occurred at mild conditions. The sorption activity of the iron reactive powder does not change substantially over several cycles of adsorption−desorption. Iron powder was characterized by the surface area measured by nitrogen adsorption at −196 °C. Oxygen capacities were determined in an argon gas flow system. The process described here can be scaled up for industrial use.
Recognition sites around the catalytic centre of DNA-dependent RNA polymerase.

WE have been studying the structure of enzymes of nucleic acid metabolism by amino-acid sequence analysis and affinity labelling techniques and hope in this way to discover specific enzyme inhibitors. We report here the inhibition of purified DNA-dependent RNA polyrnerase from Escherichia coli by the nucleoside analogues, β-D-ribosyl-6-methyl-thiopurine (MMPR, methylthioinosine) and its periodate oxidation product (MMPR-OP), and by β-D-arabinosyl-6-mercaptopurine (Ara-6MP). We also report a lack of inhibition by the arabinosides of cytosine (Ara-C) and adenine (Ara-A). The results lead us to propose a tentative stochastic model for the catalytic centre of DNA-dependent RNA polyinerase from E. coli B.
Importance of Steric Effects on the Efficiency and Fidelity of Transcription by T7 RNA Polymerase

DNA-dependent RNA polymerases such as T7 RNA polymerase (T7 RNAP) perform the transcription of DNA into mRNA with high efficiency and high fidelity. Although structural studies have provided a detailed account of the molecular basis of transcription, the relative importance of factors like hydrogen bonds and steric effects remains poorly understood. We report herein the first study aimed at systematically probing the importance of steric and electrostatic effects on the efficiency and fidelity of DNA transcription by T7 RNAP. We used synthetic nonpolar analogues of thymine with sizes varying in subangstrom increments to probe the steric requirements of T7 RNAP during the elongation mode of transcription. Enzymatic assays with internal radiolabeling were performed to compare the efficiency of transcription of modified DNA templates with a natural template containing thymine as a reference. Furthermore, we analyzed effects on the fidelity by measuring the composition of RNA transcripts by enzymatic digestion followed by two-dimensional thin layer chromatography separation. Our results demonstrate that hydrogen bonds play an important role in the efficiency of transcription but, interestingly, do not appear to be required for faithful transcription. Steric effects (size and shape variations) are found to be significant both in insertion of a new RNA base and in extension beyond it.
Effect ofEncarsiasp. nr.diaspidicola(Hymenoptera: Aphelinidae) Parasitism onCybocephalussp. nr.nipponicus(Coleoptera: Cybocephalidae) Egg Laying Choices

Abstract The beetleCybocephalussp. nr.nipponicusEndrody–Younga (Coleoptera: Cybocephalidae) and the waspEncarsiasp. nr.diaspidicola(Silvestri) (Hymenoptera: Aphelinidae) were introduced from Korea and China into the United States as part of a biological control project of euonymus scaleUnaspis euonymi(Comstock). We report the ability ofC.sp. nr.nipponicusto discriminate between parasitized and unparasitized scales in choosing scales for oviposition. Beetles avoided ovipositing in previously parasitized scales as soon as 2 days after parasitism. The effects of host age, density, and sex on parasitism levels byE.sp. nr.diaspidicolawere also measured.
The Language of Ideas and the Language of Display: Reconceptualizing “Academic Language” in Linguistically Diverse Classrooms

Introducing a distinction between language of ideas and language of display as a means of reconceptualizing what counts as “academic” language, I examine one brief stretch of talk by a small group of linguistically diverse 7th grade students in a U.S. mainstream social studies classroom designed to maximize academic and language development opportunities for English learners. I argue that focusing on how students use language to engage in academic tasks makes it possible to consider (a) the accomplishments related to academic tasks that students, both individually and in concert with others, use language to make, (b) the wide range of linguistic resources that students bring to bear on an academic task, including language that may be initially regarded as “conversational” or “informal,” and (c) students’ awareness and strategic use of different registers for different purposes and audiences.
Relationship Between Woody Plant Colonization and Typha L. Encroachment in Stormwater Detention Basins

We studied stormwater detention basins where woody vegetation removal was suspended for 2 years in Virginia, USA to determine if woody vegetation can control Typha populations and how early woody plant succession interacts with Typha, other herbaceous vegetation, and site factors. Distribution and composition of woody vegetation, Typha and non-Typha herbaceous vegetation biomass, and site factors were assessed at 100 plots in four basins ranging in age from 7 to 17 years. A greenhouse study examined the interaction of shade and soil moisture on Typha biomass and persistence. Principal component analysis identified an environmental gradient associated with greater water table depths and decreased elevation that favored Typha but negatively influenced woody vegetation. Elevation was correlated with litter layer distribution, suggesting that initial topography influences subsequent environmental characteristics and thus plant communities. Soil organic matter at 0–10 cm ranged from 5.4 to 12.7 %. Woody plants present were native species with the exception of Ailanthus altissima and Pyrus calleryana. In the greenhouse, shade and reduced soil moisture decreased Typha biomass and rhizome length. The shade effect was strongest in flooded plants and the soil moisture effect was strongest for plants in full sun. Typha in dry soil and heavy shade had 95 % less total biomass and 83 % smaller rhizomes than Typha in flooded soil and full sun, but even moderate soil moisture reductions decreased above- and below-ground biomass by 63 and 56 %, respectively. Suspending maintenance allows restoration of woody vegetation dominated by native species and may suppress Typha invasion.
A note on optimality conditions for trusses with a zero minimum cross-section†☆

Abstract Necessary and sufficient conditions for a simple class of optimal design problems are studied, with particular emphasis given to the application of the conditions to plane truss problems in the case where the minimum cross-sectional area of any bar is permitted to be zero.
Taphonomic implications of roosting behavior and trophic habits in two species of African owl

Abstract As some of the most common predators of micromammals, owls are implicated in the formation of many fossil assemblages. Actualistic research on owl-accumulated assemblages has tended to focus on owls roosting in caves. Comparatively few data are available on the roosting behavior, and prey preference of owls in open habitats. This paper presents observations on the roosting and prey habits of two sympatric species of owl in the Serengeti region of northern Tanzania, the Barn Owl, Tyto alba affinis , and the Spotted Eagle Owl, Bubo africanus . The Barn Owl and Spotted Eagle Owl are found to segregate by roosting habit, with Barn Owls occupying cavity roosts and Eagle Owls appearing on the ground or in tree crowns. Previous studies comparing these two species suggested a close similarity in trophic habits. A comparison of large samples (MNI = 1012) at cavity and exposed roosts shows identical taxonomic representation, though differences are found in the relative abundance of some taxa and significant differences in prey body mass.
Ground-Free ECG Recording with Two Electrodes

ECG recordings normally use three electrodes?two for the differential inputs of the ECG amplifier and the third for ground. We analyze those situations where the ground electrode can be eliminated. We propose a model for the source of electrical interference and determine various parameter values. Making use of experimentally obtained data for the model parameters we suggest optimal design for a two-electrode amplifier. The two-electrode design is useful for biotelemetry, portable Holter monitors, and portable arrhythmia monitors. Under certain circumstances it may be useful for grounded monitoring equipment. The two-electrode technique has the advantage that it improves patient safety by eliminating the ground electrode. Fewer electrodes make patient attachment easier and lower electrode costs.
Nonlinear normal modes in multi-mode models of an inertially coupled elastic structure

Nonlinear normal modes for elastic structures have been studied extensively in the literature. Most studies have been limited to small nonlinear motions and to structures with geometric nonlinearities. This work investigates the nonlinear normal modes in elastic structures that contain essential inertial nonlinearities. For such structures, based on the works of Crespo da Silva and Meirovitch, a general methodology is developed for obtaining multi-degree-of-freedom discretized models for structures in planar motion. The motion of each substructure is represented by a finite number of substructure admissible functions in a way that the geometric compatibility conditions are automatically assured. The multi degree-of-freedom reduced-order models capture the essential dynamics of the system and also retain explicit dependence on important physical parameters such that parametric studies can be conducted. The specific structure considered is a 3-beam elastic structure with a tip mass. Internal resonance conditions between different linear modes of the structure are identified. For the case of 1:2 internal resonance between two global modes of the structure, a two-mode nonlinear model is then developed and nonlinear normal modes for the structure are studied by the method of multiple time scales as well as by a numerical shooting technique. Bifurcations in the nonlinear normal modes are shown to arise as a function of the internal mistuning that represents variations in the tip mass in the structure. The results of the two techniques are also compared.
Mitogenic Activity of Cementum Components to Gingival Fibroblasts

Cementum forms the interface between root dentin and periodontal ligament through which periodontal connective tissue is attached to root surfaces. We have examined how cementum components influence the biological activities of gingival fibroblasts. Cementum was harvested from freshly extracted human teeth and extracted sequentially with 0.5 mol/L acetic acid, 4 mol/L guanidine-0.5 mol/L EDTA, and bacterial collagenase. The extracts were concentrated and analyzed for mitogenic activity to human gingival fibroblasts. DNA synthesis was assayed by measurement of [3 H]thymidine incorporation by quiescent fibroblasts activated to divide, and cell growth was determined by the counting of cells over a 10-day period. Results showed that extracts of cementum stimulated quiescent gingival fibroblasts to synthesize DNA and grow. The stimulation was dose-dependent, and most of the stimulatory activity was extracted by acid. Addition of small quantities of serum potentiated the mitogenic activity to levels greater tha...
Fischer–Tropsch Synthesis: Branched Paraffin Distribution for Potassium Promoted Iron Catalysts

Iron Fischer–Tropsch catalysts with varying amounts of K (0, 2, 4, 6, 10 wt%) were utilized. Except possibly for the 10 wt% catalyst, the amount of the iso-alkanes produced was essentially constant for carbon numbers from 4 to 23. Iso-alkanes accounted for about 13–15 % of the hydrocarbon products that were produced. The 2- and 3-methyl isomers were present at about two times the amount of the other methyl isomers for each carbon number. Mechanisms to account for the branching were considered but a satisfactory one could not be found.
Behavioral phenotype of neurofibromatosis, type 1.

Neurofibromatosis, type 1 (NF1) is a very common inherited disorder that was first described in the late 19th century. NF1 is associated with a myriad of behavioral manifestations in addition to its frequent and often severe medical and physical complications. Learning disability, cognitive impairment, emotional and psychosocial difficulties have been reported so frequently in neurofibromatosis that these are often considered hallmarks. This report briefly introduces the medical and physical characteristics of NF1. We then detail the behavioral manifestations of NF1 with additional discussion of possible etiologies for the high incidence of these behavioral difficulties. MRDD Research Reviews 2000;6:117-124.
The Steiner Surface Revisited

The isoparametric method used in finite element calculations is outlined and the implication of piecewise surface approximation by rational sur­faces is discussed. The simplest non-trivial case is that of the Steiner surface. Examples of the occurrence of this surface are given and some of the properties of the surface discussed. A norm for approximation by a Steiner surface is given.
Using Abell's narrative method to build a theory: The case of the theory of distributive justice and its generalization to the theory of comparison processes

This paper examines the usefulness for theoretical work of the narrative method proposed by Peter Abell. Our assessment proceeds by using the narrative method to perform the two main tasks of theoretical analysis—constructing postulates and deriving predictions. Tb illustrate, we focus on the theory of distributive justice and the more general theory of comparison processes to which it led. The results of our assessment of the usefulness of Abell's narrative method for theoretical work indicate that the narrative method has far wider applicability than Abell has claimed for it. For example, (i) it is useful for all theoretical work in the sociobehavioral sciences, not only for theoretical work based on game theory, (ii) it is useful for analyzing thought‐experiments as well as narrative accounts of actual actions and events, and (iii) the events in the narrative need not be restricted to human actions but can include events not traceable to human agency. We conclude also that Abell's narrative method comp...
CNS cell groups involved in the control of the ischiocavernosus and bulbospongiosus muscles: a transneuronal tracing study using pseudorabies virus.

Transneuronal tracing techniques were used to identify spinal and brainstem neurons involved in the control of perineal muscles in the male rat. Two penile muscles, the bulbospongiosus and ischiocavernosus muscles, were injected with Bartha's strain of pseudorabies virus. After survival periods of 2, 4, and 5 days, the rats were killed and viral labeled neurons identified by immunohistochemistry. After a 2 day survival period, only pudendal motoneurons were labeled. More spinal and brainstem neurons were labeled at longer survival times. Putative spinal interneurons were found from T13 to S1. Large numbers of neurons were found in the lateral horn of the T13-L2 and L6-S1 segments which contain sympathetic and parasympathetic preganglionic neurons, respectively. However, retrograde labeling experiments verified that very few of the viral neurons were preganglionic neurons. Other labeled neurons were found in the intermediate cord, especially around the central canal. Relatively few labeled neurons were seen in the dorsal or ventral horn. In the brainstem, consistent labeling was seen in the ventrolateral medulla, raphe pallidus, and magnus, the A5 and locus ceruleus noradrenergic cell groups, Barrington's nucleus in the pontine tegmentum, the periaqueductal gray, and the paraventricular nucleus of the hypothalamus. The transneuronal labeling was consistent with what is currently known of the central nervous system (CNS) control of the perineal muscles. © 1996 Wiley-Liss, Inc.
Effect of nonequilibrium interface kinetics on cellular breakdown of planar interfaces during rapid solidification of Si-Sn

Abstract During rapid solidification, nonequilibrium interface kinetics alter the predictions of the Mullins-Sekerka theory for the stability of a planar interface against cellular breakdown. The velocity-dependence of the partition coefficient and of the Sn concentration at the onset of cellular breakdown have been measured during pulsed laser melting of Si-Sn alloys. The Mullins-Sekerka theory is modified by inserting a velocity-dependent partition coefficient and a velocity-dependent slope of the “kinetic liquids”, both of which are extracted from the continuous growth model for interface kinetics. These nonequilibrium interface kinetic effects increase the predicted critical concentration for cellular breakdown by two orders of magnitude for Sn in Si, and account fairly well for the experimental results.
Optimal load path input in tube hydroforming machines

Tube hydroforming (THF) is a metal-forming process in which a tube is plastically deformed to conform to the die cavity by injecting a pressurized fluid inside the tube. To ensure that enough material is supplied to the die cavity, the tube ends are usually pushed towards the die cavity to feed the material. To successfully hydroform a part, good coordination between fluid pressure and material feed is necessary. This pressure–material displacement relationship is known as a load path. The load path is specific to a part, and it is entered in a THF machine as pressure versus time and displacement versus time input variables. A methodology of decomposing the pressure–displacement loading path as a time variable to obtain pressure–time and displacement–time variants that are optimal for the THF machine system is presented. The THF experiments for double T-shaped parts are carried out to demonstrate that using different pressure–time and displacement–time variants can result in a significant increase in the ...
HYDROGEN SALINE A REAL GAS

![Figure][1] The 2005 announcement in Science that the inhalation of hydrogen sulfide gas (H2S) could induce a reversible hypometabolic state in mice, similar to suspended animation, set off a flurry of speculation and investigation into the mechanisms and potential therapies suggested by the
Stability studies in pipe flows unsing water and dilute polymer solutions

The response of water and 20 ppm. solutions of Separan AP-30 and Polyox WSR 301 to the periodic motion of a thin sleeve was measured using a laser Doppler velocimeter. The sleeeve was moved in an axial direction by an external coupling at frequencies from 1/4 to 1.O Hz and at amplitudes of 1/2 to 2 in. The flow filed downstream of the distrbance was found to consist of three regions: 1. a near field with a separation wake from the sleeve moving toward the piep centerline; 2. an intermediate field in which alternate laminar and turbulent slugs passed a point; and 3. a far field with decaying turbulent lfow. Defferences in the behavior of water flows and polymer flows appeared in each region. In the near field, wakes spread faster in water flows. In the intermediate field, the laminar slugs disappeared into turbulence more rapidly in water flows. And in the far field, the turbulence was not as developed in the polymer flows. Detailed statistical evaluations were made on the signals in each region for a Reynolds number of 2000. The response of the dilte polymer polymer solutions appeared to be governed by the initial interaction with the sleeve. Fewer high frequencies were generated than in the pure solvent so the periodic disturbance persisted downstream. In pure water the eddies from the separation wake interacted strongly with the periodic distrurbance leading to rapid decay of the periodic portion. Shear rates were not high enough to attribute the dilute polymer differences to viscoelastic effects.