cssi/SciSciGPT-SciSciNet huggingface dataset:
Genes involved in matrix formation in Pseudomonas aeruginosa PA14 biofilms

Pseudomonas aeruginosa forms diverse matrix-enclosed surface-associated multicellular assemblages (biofilms) that aid in its survival in a variety of environments. One such biofilm is the pellicle that forms at the air-liquid interface in standing cultures. We screened for transposon insertion mutants of P. aeruginosa PA14 that were unable to form pellicles. Analysis of these mutants led to the identification of seven adjacent genes, named pel genes, the products of which appear to be involved in the formation of the pellicle's extracellular matrix. In addition to being required for pellicle formation, the pel genes are also required for the formation of solid surface-associated biofilms. Sequence analyses predicted that three pel genes encode transmembrane proteins and that five pel genes have functional homologues involved in carbohydrate processing. Microscopic and macroscopic observations revealed that wild-type P. aeruginosa PA14 produces a cellulase-sensitive extracellular matrix able to bind Congo red; no extracellular matrix was produced by the pel mutants. A comparison of the carbohydrates produced by the wild-type strain and pel mutants suggested that glucose was a principal component of the matrix material. Together, these results suggest that the pel genes are responsible for the production of a glucose-rich matrix material required for the formation of biofilms by P. aeruginosa PA14.
Mechanism of silicon induced alleviation of aluminum phytotoxicity

Complexation of aluminum (Al) with silicon (Si) has been attributed as a mechanism of Si induced alleviation of Al toxicity to plants. Effects of various concentrations of Si (0, 534, 1068, or 1602 micromolar) on root growth of two sorghum cultivar seedlings (NB9040 and Martin) was evaluated in nutrient solutions containing 0 or 296 micromolar Al. Three experiments were conducted with variation in the sequence of pH adjustment of the solution, and addition of Al and Si stock solutions. In solutions containing 296 micromolar Al with no Si, growth of sorghum seedlings was significantly decreased as compared to that of the seedlings grown in solutions containing 0 Al. Root growth of seedlings of both cultivars in solutions containing 296 micromolar Al improved significantly with increasing concentrations of Si, but only when Al was added to the basal nutrient solution following the addition of Si without lowering the solution pH. Addition of Si to the basal nutrient solution increased the pH greater than or equal to 10.0, which facilitated precipitation of Al, thus decreasing its toxicity. If the solution pH was lowered to 4.0 following the addition of Si, prior to the addition of Al, the toxicity of Al was least influenced by the presence of Si in solution within the range of 534 to 1602 micromolar. Silicon-induced alleviation of Al toxicity appears to be due to pH effects and not the direct effects of Si on Al in solutions.
Studies of High-Gain Micro-Channel Plate Photomultipliers

The characteristics and performance of several kinds of high-gain micro-channel plate photomultipliers have been investigated. Special attention was directed towards i) lifetime studies, ii) performance in the magnetic field, and iii) timing properties. Lifetime studies include separate investigations of the photocathode quentum efficiency degradation caused by ion feedback, and the deterioration of the micro-channel plate gain. The dependence of the micro-channel plate photomultiplier gain on the intensity and the direction of the magnetic field (up to 7 kGauss) is reported.
Consumption of a toxic food by caterpillars increases with dietary exposure: support for a role of induced detoxification enzymes

We examined whether there is a link between feeding behavior and detoxification enzyme activity, which increases over time in proportion to the ingested dose of toxic allelochemicals. We hypothesized that, for insects consuming a toxic but nondeterrent food, consumption would initially decline but then increase after continuous exposure in conjunction with the induction of detoxification enzyme activity. We tested this hypothesis by observing the feeding behavior of fall armyworms (Spodoptera frugiperda) when offered diets containing indole 3-carbinol (I3C), a well-known inducer of detoxification enzymes in this species. The I3C concentrations used were toxic but nondeterrent, thereby avoiding any confounding influence of preingestive responses. The feeding pattern of caterpillars previously unexposed to dietary I3C (i.e. with basal detoxification enzyme activity) was substantially altered when offered I3C-containing diets. Compared with control caterpillars fed I3C-free diets, they exhibited fewer feeding bouts and had a greater proportion of long (> 60 min) non-feeding pauses between bouts. In contrast, the feeding pattern of caterpillars pre-exposed to an I3C diet (i.e. with induced detoxification enzyme activity) did not differ from that of control caterpillars. We conclude that there is a relationship between feeding behavior and detoxification activity in these caterpillars, and propose two postingestive mechanisms that could link these processes.
Biological responses of hybridoma cells to hydrodynamic shear in an agitated bioreactor

Abstract Effects of long-term hydrodynamic shear on hybridoma cells were investigated in a 250-ml continuous stirred-tank reactor (CSTR). Cells grown at steady state were subjected to step changes in agitation rates. Cell viability, glucose consumption, and monoclonal antibody (MAb) production were determined at high agitation rates and compared with the control (100 rev min−1). Impeller tip speeds higher than 40 cm s−1 caused a significant drop in cell concentration and respiration activity, and increased lactate dehydrogenase (LDH) release to the culture medium. Also, high agitation speeds caused a decrease in MAb concentration and an increase in specific glucose consumption rate. The effects of dilution rate and serum concentration on the sensitivity of hybridoma cells to hydrodynamic shear were determined. Serum was found to protect the cells against shear damage and had a significant positive effect on hybridoma growth and MAb production. Shear damage on cells in CSTR was approximated to first-order kinetics. The death rate constant increased sharply at impeller tip speeds above 40 cm s−1.
A comment on the theory of mode locking and frequency doubling

The time-domain theory of the mode-locked and frequency-doubled laser by J. Falk depends greatly on the particular Gaussian approximation to the pulse transmitted from the frequency doubler. This correspondence examines an alternative approximation which appears to be a better fit to the actual pulse shape and which gives substantially different results for pulsewidth.
Consistency of a phylogenetic tree maximum likelihood estimator

Abstract Phylogenetic trees represent the order and extent of genetic divergence of a fixed collection of organisms. Order of divergence is represented via the tree structure, and extent of divergence by the branch lengths. Both the tree’s structure and branch lengths are unknown parameters and the tree is estimated using sequence information sampled at a number of genetic sites. Under the model of genetic Brownian motion, we prove that as the number of genetic sites that are sampled becomes large, the maximum likelihood estimator of the tree is consistent. (Our maximum likelihood estimator treats each site as an independent data point, which is different from concatenating the sites.) Existing arguments for consistency rely on the assumption of a finite parameter space or only apply to transition probability matrix-based models, and do not hold here due to the continuous model for branch lengths. The metric space of Billera et al. (2001) is central to the proof. We conclude with some comments on the role of parametric methods in tree estimation.
Quantitative variation of ribosomal RNA genes in flax genotrophs

The variation in the proportion of the DNA coding for ribosomal RNA in three flax genotrophs, and the inheritance of this proportion in crosses between them were determined. DNA variation was observed and lines could be selected from within a genotroph with differing proportions of rDNA. The degree of variation increased when the genotrophs were crossed, the extent of the increase being dependent on the particular genotrophs involved in the cross. The variation extended into the F2 and F3 generations. The mean values of F2 and F3 families were not highly correlated with the value of the parental plant from which they were derived. In one cross the F2 and F3 means were close to the average value of the two parents involved in the original cross. In the other cross, the F1, F2 and F3 means were all less than the average value of the two original parents.
Resequencing of IRS2 reveals rare variants for obesity but not fasting glucose homeostasis in Hispanic children

Our objective was to resequence insulin receptor substrate 2 (IRS2) to identify variants associated with obesity- and diabetes-related traits in Hispanic children. Exonic and intronic segments, 5′ ...
Structural characterization of protein–polymer conjugates. I. Assessing heterogeneity of a small PEGylated protein and mapping conjugation sites using ion exchange chromatography and top-down tandem mass spectrometry

Abstract PEGylated proteins are a rapidly growing class of biopharmaceutical products, but their analytical characterization remains a formidable problem due to the extreme heterogeneity of these species. While significant advances have been made in recent years in this field due to integration of mass spectrometry in the analytical workflow, quick identification of PEGylation sites remains an unmet goal, particularly if several isoforms of the protein–polymer conjugate are present in the sample. To achieve this objective, a new method is developed, which utilizes a combination of ion exchange chromatography and top-down mass spectrometry consisting of two consecutive fragmentation steps (MS3) to identify various conjugates. The method is tested with a complex mixture of products of ubiquitin conjugation with 5 kDa PEG.
Best practices in community‐based prevention for youth substance reduction: towards strengths‐based positive development policy

Substance use among youth remains a major public health and safety concern. One fundamental way to address youth substance use prevention is to keep young people on a positive trajectory by engaging them in positive activities from early years of their childhood. In this article, the author offers a best practice analysis of systematic review about 12 selected community-based preventions, and proposes policy changes towards incorporating a strengths perspective. A substantive, methodological, and value-based critical analysis of the strongly effective preventions was conducted. A strengths-based positive youth development perspective is specified as one feasible needed improvement and subsequent policy changes in the school district as well as in the local, state, and federal levels are proposed along with the suggestion of a mandated community youth participation strategy. © 2008 Wiley Periodicals, Inc.
Online processing of novel noun–noun compounds: Eye movement evidence

Three eye-tracking experiments investigated online processing of novel noun–noun compounds. The experiments compared processing of compounds that are difficult to interpret in isolation (e.g., dict...
Processing and properties of metal matrix composites containing discontinuous reinforcement

Abstract Metal matrix composite materials which utilize discontinuous-type reinforcement undergo unit operations associated with ingot, powder or cast metal manufacturing in addition to their own unique operations. An attempt is made to summarize the scope of operations for both cast- and powder-based processing and identify processing issues which cause matrix-reinforcement interface and property variability in discontinuous metal matrix composites.
Sustainability Assessment of Industrial Systems under Uncertainty: A Fuzzy Logic Based Approach to Short-Term to Midterm Predictions

The sustainability assessment of industrial systems is always a very challenging task due to the existence of various types of uncertainties that are associated with the available data, assessable information, possessed knowledge, and problem understanding, etc. This paper introduces a fuzzy logic based approach for the effective short- and long-term assessment of industrial sustainability under the restrictions of aleatory and epistemic uncertainties. A comprehensive study on a metal-finishing-centered industrial zone is illustrated to show the efficacy of the introduced methodology.
Another look at symmetry testing

Abstract This paper explores implementable alternatives for the F test of Slutsky symmetry when the contemporaneous covariance matrix of the error terms is unknown. The power of the test is also considered.
Realized versus fundamental niche functions in a model of chaparral response to climatic change

Abstract Simulation models are being developed and used to project the effects of global climatic change, i.e., the greenhouse effect, on the dynamics and pattern of vegetation. Many models use information about species' current ranges relative to climatic variables, i.e., their realized niche, to derive response functions. Using a simulation model for Californian chaparral, we compare the projections of vegetation using response functions representing a calculated realized niche and an assumed fundamental niche. The realized niche response functions are based on the distributions of species along gradients of annual precipitation and mean temperatures of the coldest and warmest months. Then, assuming that moderate increases in precipitation (as projected by some general circulation models for Californian chaparral) will reduce stress, we modified the functions to produce assumed fundamental niche responses. Compared to the projections based on the realized niche, use of the fundamental niche produces more continuous cover, lags in change, and different dominance following climatic change. The effects of increased precipitation per se are lasting using the realized niche responses, but only temporary using the assumed fundamental niche responses. More detailed information on actual responses is needed, but the physiological information now available would be useful only in models that would consume vast computing resources.
Dichloridobis(3,4,5-trimethyl-1H-pyrazole-κN2)cobalt(II)

In the title compound, [CoIICl2(C6H10N2)2], a pair of 3,4,5-trimethyl­pyrazoles act as monodentate ligands. Two Cl− anions are also bonded directly to the CoII atom, which has a CoN2Cl2 chromophore in a slightly distorted tetra­hedral geometry. The two mol­ecules in the asymmetric unit are related by an approximate twofold rotation roughly parallel to the a axis. The amino H atom in the pyrazole ring participates in weak N—H⋯Cl hydrogen bonds to form chains that propagate roughly parallel to the c axis.
A placement examination for computer science II

Students enrolling in Computer Science II at Mississippi State University (MSU) have widely varying backgrounds. Some have taken the prerequisite course at MSU, some have transferred from community colleges offering the prerequisite, and some are new graduate students with undergraduate deficiencies. Proper placement of students in the introductory courses is necessary to give those students with little background in object-oriented software development an opportunity for success, while challenging students who may have had substantial programming experience elsewhere. The Department has developed and tested a placement examination. The examination helps students decide if they should enroll in an introductory course that assumes some previous programming experience without object-oriented software development, or if they should begin in Computer Science II that assumes knowledge of C++ with object-oriented design. The score on the placement exam demonstrated predictive power when trying to distinguish, coarsely, between those students who will probably pass the Computer Science II course and those students who are at risk of failing the course.
Moral compromise, civic friendship, and political reconciliation

Instrumentalism about moral compromise in politics appears inconsistent with accepting both the existence of non-instrumental or principled reasons for moral compromise in close personal friendships and a rich ideal of civic friendship. Using a robust conception of political reconciliation during democratic transitions as an example of civic friendship, I argue that all three claims are compatible. Spouses have principled reasons for compromise because they commit to sharing responsibility for their joint success as partners in life, and not because their relationship involves strong affective attitudes of goodwill, solidarity, trust, and the like. Since shared responsibility for ends is an inappropriate element in the political relationship between citizens, the members of a divided society may manifest the constitutive attitudes of political reconciliation without any commitment to principled reasons for moral compromise.
BOGOLIUBOV TRANSFORMATIONS AND CALCULATION OF COUPLING-CONSTANTS

It is shown that quarks in different situations are often related by a Bogoliubov transformation involving both quark and antiquark degrees of freedom. This is exploited, within the context of the MIT bag model, to provide a calculation of the $\ensuremath{\pi}\mathrm{NN}$ and $\ensuremath{\rho}\mathrm{NN}$ coupling constants, with encouraging results.
Proximal femoral neck penetration after flexible intramedullary nailing for pediatric femur fractures: a rare complication

Flexible intramedullary nailing is a common method used to treat pediatric femur fractures. Complication rates can be high, but most complications are considered minor and do not result in additional unplanned surgeries. Proximal nail penetration is a complication that has only been described once before. The penetration may be asymptomatic, but is still best to be avoided. Two cases of proximal nail penetration of the femoral neck region during nail insertion are presented. A review of the literature with regard to complications and suggestions for avoidance of proximal nail penetration is offered.
The effect of environmental factors on phytoplankton growth: Temperature and the interactions of temperature with nutrient limitation1

The combined stress of nutrient limitation and suboptimal temperature on growth was studied with turbidostat and chemostat cultures of Scenedesmus sp. and Asterionella formosa. The combined effects were greater than the sum of individual effects and were not multiplicative. In N- and P-limited Scenedesmus sp. and A. formosa the cell (q) of both limiting and nonlimiting nutrients increased with decreasing temperature. At a given temperature cell quotas of limiting nutrients also increased with the growth rate (µ) and followed a saturation function. Higher values of the minimum cell quota (qo) at lower temperatures show that cells require more nutrient with decreasing temperature. The change of qo with temperature varies with the type of limiting nutrient. This change for N and P in Scenedesmus sp. suggests that their optimum ratio, the ratio at which one limitation changes over to the other, is higher at suboptimal temperatures. Cell quotas of nutrient-sufficient cultures (qm) for C, N, and P and cellular chlorophyll a concentration increased with decreasing temperature. The quota of each nonlimiting nutrient in nutrient-limited cultures had the same value as qm. The rate of protein synthesis per unit RNA decreased with temperature. The highest apparent maximum N uptake was observed at 15°C for N-limited Scenedesmus sp. growing at 0.5·d‒1. The optimal growth temperature range, however, was 20°–25°C. The highest apparent maximum P uptake in A. formosa was found at 19°–20°C, when µ = 0.4·d‒1. These temperatures were also optimal for growth.
CONCHOCELIS GROWTH AND PHOTOPERIODIC CONTROL OF CONCHOSPORE RELEASE IN PORPHYRA TORTA (RHODOPHYTA)

We have determined the conditions which give optimal growth and conchospore release in laboratory cultures of free conchocelis of the red alga Porphyra torta Krishnamurthy. With cool white fluorescent light on a 16L.8D photoregime, the fastest sustained growth (5% volume increase d−1) was observed from 10–15°C and 25–100 μE-m −2.s−1; slightly faster growth was observed at 15°C and 300 μE.m−2.s−1, but such conditions are close to lethal. Conchoporangin will form under a wide range of conditions in conchocelis of this species. However, conchospores will mature and release only when the cultures are exposed to a short day photoperiod. The critical pholoperiod is just shorter than 12 h, The minimum number of photoinductive cycles for complete conchospore release is four for a range of conditions but can be just one depending on pretreatment.
External-internal carotid artery transposition for repair of multiple pseudoaneurysms from penetrating injury in a pediatric patient

A 13-year-old boy was transferred to our trauma center after sustaining a shotgun wound to his neck and head. Workup revealed an injury to his tonsillar fossa, a pseudoaneurysm less than 4 mm in his internal carotid artery, and diffuse cerebral edema. After management of his intracranial hypertension, follow-up angiogram revealed 4 pseudoaneurysms in his internal carotid artery. In the operating room, the affected segment was resected, and a transposition of the external carotid artery to the internal carotid artery was performed. Workup of penetrating neck trauma and management options for internal carotid artery pseudoaneurysms in a pediatric patient are discussed.
To Parent or Provide? the Effect of the Provider Role on Low-Income Men's Decisions about Fatherhood and Paternal Engagement

Results of a qualitative study of low-income men’s experience with the provider role are reported here. This study explored how 47 low-income men construct, express, and negotiate their identities as fathers and providers, and perceived barriers presented by the provider role. Overall, fathers consistently expressed the need to redefine the provider role in to include social and emotional components. Additionally, fathers articulated the many barriers and social pressures they experience as a result of the provider role, and how these barriers create an environment that is detrimental to their attempts at being a father, and how this could lead to their disengagement from the lives of their children.
Structure and assembly of the Escherichia coli transcription termination factor rho and its interactions with RNA. I: Cryoelectron microscopic studies

Abstract Cryoelectron microscopy has been used to visualize the Escherichia coli transcription termination protein rho in a vitreously frozen state, without the use of stains, fixatives or other chemical perturbants. In the absence of RNA cofactor, a variety of structures are observed, reflecting the heterogeneity of complexes formed by rho at protein concentrations near the physiological range (3 to 10 μ m ). One of the most common structural motifs we see is a six-membered ring of rho subunits (present as either a closed or “notched” circle), which corresponds to the predominant hexameric association state of the protein. Also visible are smaller oligomeric structures, present as curved lines of rho subunits, which probably represent the lower association states of the protein that coexist with the hexamer at these protein concentrations. Addition of oligomers of ribocytosine (rC) of defined lengths (23-mers and 100-mers) results in the generation of more homogenous populations of rho oligomers. In the presence of (rC) 23 , all identifiable particles appear either as closed or as notched hexameric circles. A small fraction of these particles are of visibly higher density, and are identified with the dodecamers expected as a subpopulation of rho under these conditions. Binding of (rC) 100 , an oligomer of length greater than that needed to span the entire hexamer binding site, results in a uniform population of closed circular hexamers. In some images additional features are visible at either the centers or the peripheries of the particles. These features may correspond to the excess length of the rC strands bound to the hexamers. The distributions of particles observed under the various experimental conditions used correlate well to those deduced from physical biochemical studies (Seifried et al. , accompanying paper).
Why the SEC's First Attempt at Hedge Fund Adviser Registration Failed

In December 2004, the Securities and Exchange Commission, (SEC), by a vote of 3-2, promulgated regulations 203(b)(3)-2, an amendment to the Investment Advisers Act of 1940 (Advisers Act), that required many hedge fund managers to register with the SEC for the first time. In discussing the regulation, the majority wrote that this regulation was necessary because the regulatory program for hedge funds and hedge fund managers in place at the time were inadequate and recent growth in the hedge fund industry had led to several cases of fraud and retailization. On June 23, 2006, the United States Court of Appeals for the District of Columbia overturned this regulation. The purpose of this article is to present the arguments that precipitated the regulation and to discuss the grounds on which the regulation was ultimately overturned.
Effect of infection with T-even phage on the inducible synthesis of β-galactosidase in Escherichia coli

Abstract The induction of β- d -galactosidase in Escherichia coli is inhibited promptly upon infection with T-even bacteriophage. This inhibition does not require phage-specific protein synthesis. When a pre-induced culture is infected, its capacity to form β-galactosidase decays exponentially after a brief delay. In cells carrying the F episome (F+, Hfr or F lac), this decay of enzyme-forming capacity proceeds at the same rate, whether induction is arrested by phage infection or by inducer removal. On the other hand, in F− strains the rate of decay after phage infection is twice as fast as after inducer removal. No differences in phage development are detectable in F+ and F− strains. Irradiation of the phage particles with small doses of ultraviolet light, insufficient to affect the production of early phage enzymes, completely abolishes the effect of phage on the decay of β-galactosidase-forming capacity. Therefore, the ability to accelerate the breakdown may reside in the genetic material of the virus. This phage function is repressed by the F episome of the host.
Indium Hybridization of Large Format TES Bolometer Arrays to Readout Multiplexers for Far-Infrared Astronomy

The advance of new detector technologies combined with enhanced fabrication methods has resulted in an increase in development of large format arrays. The next generation of scientific instruments will utilize detectors containing hundreds to thousands of elements providing a more efficient means to conduct large area sky surveys. Some notable detectors include a 32x32 x-ray microcalorimeter for Constellation-X, an infrared bolometer called SAFIRE to fly on the airborne observatory SOFIA, and the sub-millimeter bolometer SCUBA-2 to be deployed at the JCMT which will use more than 10,000 elements for two colors, each color using four 32x40 arrays. Of these detectors, SCUBA-2 is farthest along in development and uses indium hybridization to multiplexers for readout of the large number of elements, a technology that will be required to enable the next generation of large format arrays. Our current efforts in working toward large format arrays have produced GISMO, the Goddard IRAM Superconducting 2-Millimeter observer. GISMO is a far infrared instrument to be field tested later this year at the IRAM 30 meter telescope in Spain. GISMO utilizes transition edge sensor (TES) technology in an 8x16 filled array format that allows for typical fan-out wiring and wire-bonding to four 1x32 NIST multiplexers. GISMO'S electrical wiring is routed along the tops of 30 micron walls which also serve as the mechanical framework for the array. This architecture works well for the 128 element array, but is approaching the limit for routing the necessary wires along the surface while maintaining a high fill factor. Larger format arrays will benefit greatly from making electrical connections through the wafer to the backside, where they can be hybridized to a read-out substrate tailored to handling the wiring scheme. The next generation array we are developing is a 32x40 element array on a pitch of 1135 microns that conforms to the NIST multiplexer, already developed for the SCUBA-2 instrument This architecture will utilize electrical connections that route from the TES to the support frame and through the wafer. The detector chip will then be hybridized to the NIST multiplexer via indium bump bonding. In our development scheme we are using substrates that allow for diagnostic testing of electrical continuity across the entire array and we are testing our process to minimize or eliminate any contact resistance at metal interfaces. Our goal is hybridizing a fully functional 32x40 array of TES bolometers to a NIST multiplexer. The following work presents our current progress toward enabling this technology.
Characterization of Dendrimer-Gold Nanocomposite Materials

Gold-dendrimer nanocomposite materials have various applications in catalysis, optics, biological sensing, cancer therapeutics, as well as building blocks to assemble functional films. Primary amine-terminated poly(amidoamine) (PAMAM) dendrimers of different generations (generation 2 through 6) were used as templates to synthesize gold-dendrimer hybrid nanocomposites. UV-Vis spectrometry, fluorescence, transmission electron microscope (TEM), zeta-potential, and polyacrylamide gel electrophoresis (PAGE) were used to extensively characterize these nanocomposite materials. Results indicate that the structure of gold-dendrimer nanocomposites changes as the function of generation and their size decreases with the increase of the generation number of dendrimer templates. TEM shows that aggregated gold-dendrimer nanocomposites are polycrystalline. These nanocomposites are fluorescent and display a stronger emission intensity (458 nm) than commercially available gold nanoparticles of similar size do. PAGE analysis shows that the gold-dendrimer nanocomposites have electrophoretic migration patterns that are similar to those of the corresponding dendrimer templates. The combination of applied different analytical techniques provides new insights into the structure and properties of gold-dendrimer nanocomposite materials.
User-Centric Organization of Search Results

The authors investigated the use of microblogs&#x2014;or weibos&#x2014;and related censorship practices using 111 million microblogs collected between 1 January and 30 June 2012. Using a matched case-control study design helped researchers determine a list of Chinese terms that discriminate censored and uncensored posts written by the same microbloggers. This list includes homophones and puns created by Chinese microbloggers to circumvent the censors successfully. The study's design also allowed for evaluating the new real-name registration system's impact on microbloggers' posting activities. Findings suggest that this policy might have stopped some microbloggers from writing about social and political subjects.
Trojan wave packets: Mathieu theory and generation from circular states

We present an analytic theory of three-dimensional Trojan (stable nonspreading) wave packets. The theory is valid beyond the harmonic approximation presented previously. We show that electron wave packets that are both radially and angularly well localized can be generated from an angularly completely delocalized state (a circular Rydberg state) by adiabatic switching of a circularly polarized electric field. Confinement of the Rydberg electron results from the suppression of the nonlinearity of the Coulomb spectrum, the same nonlinearity that is responsible for wave-packet spreading and revivals in the absence of the applied field. A comparison with the harmonic approach is also presented, as well as the results of numerical experiments based on integration of the time-dependent and field-dependent Schr\"odinger equation for the electron. \textcopyright{} 1996 The American Physical Society.
Experimental Demagnetizing Factors for Disk Samples Magnetized Along a Diameter

Demagnetizing factors for disk samples of a commercial 80Ni permalloy have been measured using a vibrating sample magnetometer with fields provided by a Helmholtz coil pair. The range of values of m (diameter/thickness) is from 12.5 to 385. The experimental values of N are significantly higher than those calculated for an ellipsoid, but lower than those calculated assuming uniform magnetization
A model for sedimentation in inhomogeneous media. II. Compressibility of aqueous and organic solvents.

Abstract The effects of solvent compressibility on the sedimentation behavior of macromolecules as observed in analytical ultracentrifugation are examined. Expressions for the density and pressure distributions in the solution column are derived and combined with the finite element solution of the Lamm equation in inhomogeneous media to predict the macromolecular concentration distributions under different conditions. Independently, analytical expressions are derived for the sedimentation of non-diffusing particles in the limit of low compressibility. Both models are quantitatively consistent and predict solvent compressibility to result in a reduction of the sedimentation rate along the solution column and a continuous accumulation of solutes in the plateau region. For both organic and aqueous solvents, the calculated deviations from the sedimentation in incompressible media can be very large and substantially above the measurement error. Assuming conventional configurations used for sedimentation velocity experiments in analytical ultracentrifugation, neglect of the compressibility of water leads to systematic errors underestimating sedimentation coefficients by approximately 1% at a rotor speeds of 45 000 rpm, but increasing to 2–5% with increasing rotor speeds and decreasing macromolecular size. The proposed finite element solution of the Lamm equation can be used to take solvent compressibility quantitatively into account in direct boundary models for discrete species, sedimentation coefficient distributions or molar mass distributions. Using the analytical expressions for the sedimentation of non-diffusing particles, the ls-g*(s) distribution of apparent sedimentation coefficients is extended to the analysis of sedimentation in compressible solvents. The consideration of solvent compressibility is highly relevant not only when using organic solvents, but also in aqueous solvents when precise sedimentation coefficients are needed, for example, for hydrodynamic modeling.
The induction of cell-mediated immunity and tolerance to insulin with insulin coupled to syngeneic lymphoid cells.

Abstract The induction of delayed type hypersensitivity (DTH) and tolerance to DTH against bovine insulin in mice were explored. DTH was induced with insulin in complete Freund's adjuvant (CFA) and was assessed by ear swelling in vivo and by antigen-driven cell proliferation in vitro . Using the concept that thymus cell unresponsiveness is most easily accomplished via antigen on syngeneic membranes, tolerance was induced by iv injection of syngeneic lymphoid cells which had been coupled to insulin with carbodiimide. Mice tolerized with insulin-coupled cells and then sensitized with insulin-CFA had diminished ear swelling in vivo and decreased insulin-driven cell proliferation in vitro . This unresponsiveness was antigen specific but was also inconstant in degree with regard to suppression of ear swelling, most likely because of variability in coupling of insulin to cells. Proliferative responses were more uniformly suppressed, suggesting the possibility that two target cells were being tolerized. Thus, as with other proteins, the biologically active insulin can be used to induce tolerance.
High-resolution record of cyclic climatic change during the past 4 ka from Lake Turkana, Kenya

Profiles of carbonate content and lamination thickness in an 11.3 m core from Lake Turkana are interpreted as a record of climatic change for the past 4 ka. On a time scale of millennia, the data agree with other paleohydrologic records from sub-Saharan east Africa. Time-series analysis of both data sets reveal periods of about 270,200, 165, and 100 yr. The thickness data suggest additional periods of about 78, 44, 31, 25, and possibly 20 yr. The sediments consist of laminated light and dark couplets, which are interpreted as a response to an average 4-yr variability in the hydrology of the Ethiopian Pla- teau. We suggest that this may be a feedback from the El Nino-Southern Oscillation.
Fault Growth and Acoustic Emissions in Confined Granite

The failure process in a brittle granite was studied by using acoustic emission techniques to obtain three dimensional locations of the microfracturing events. During a creep experiment the nucleation of faulting coincided with the onset of tertiary creep, but the development of the fault could not be followed because the failure occurred catastrophically. A technique has been developed that enables the failure process to be stabilized by controlling the axial stress to maintain a constant acoustic emission rate. As a result the post-failure stress-strain curve has been followed quasi-statically, extending to hours the fault growth process that normally would occur violently in a fraction of a second. The results from the rate-controlled experiments show that the fault plane nucleated at a point on the sample surface after the stress-strain curve reached its peak. Before nucleation, the microcrack growth was distributed throughout the sample. The fault plane then grew outward from the nucleation site and was accompanied by a gradual drop in stress. Acoustic emission locations showed that the fault propagated as a fracture front (process zone) with dimensions of 1 to 3 cm. As the fracture front passed by a given fixed point on the fault plane, the subsequent acousticmore » emission would drop. When growth was allowed to progress until the fault bisected the sample, the stress dropped to the frictional strength. These observations are in accord with the behavior predicted by Rudnicki and Rice`s bifurcation analysis but conflict with experiments used to infer that shear localization would occur in brittle rock while the material is still hardening.« less
Pediatric Graves' disease: controversies in management.

Background/Aims: Graves’ disease (GD) is the most common cause of thyrotoxicosis in children and adolescents. Caused by immunologic stimulation of the thyroid-stimulating hormone re
A decision making framework for assessing control strategies for ground level ozone

Abstract This paper presents a decision-making framework (DMF) for selecting ozone control strategies based on reductions of precursor emissions that are targeted by time and location. Conventional across-the-board reductions are uniform throughout the region and throughout the day. The DMF is comprised of four phases: (1) Initialization, (2) Experimental Design and Data Mining, (3) Metamodeling, and (4) Optimization. This paper details the first three and presents an example for selecting strategies in the optimization phase. Specifically, to enable an efficient optimization phase, metamodels for maximum 8-h averaged ozone are employed to represent the output from an advanced photochemical model, such as CAMx. The process for each phase is presented for a Dallas Fort Worth (DFW) 2009 future emission scenario, based on a 10-day meteorological episode from August 13–22, 1999. Over 600 emission variables were identified in three source categories viz. point, area (includes non-road) and line (on-road). The DFW application demonstrates how control measures can be efficiently explored in a targeted manner instead of using the conventional “trial and error” approach.
Surface Preparation and Passivation of III-V Substrates for Future Ultra-High Speed, Low Power Logic Applications

III-V compound semiconductors have been recognized among the potential options for continuing transistor power-performance scaling owing to their ultra high charge carrier mobility. In order to realize their potential in high performance and lower-power digital logic applications, there must be strong gate control and a high Ion-Ioff ratio, achieved by integrating a stable, ultra thin high-K dielectric between the semiconductor and the gate [1, 2]. Unlike Si, which has long benefited from its very stable native oxide, III-V materials suffer from their poor native oxides that cause charge traps and Fermi level pinning at the semiconductor-oxide interface. Attempts to deposit high-K directly on III-V often produce MIS structures with fast surface state and CV instability [3].
Changes in Ciprofloxacin Utilization as Shown in a Large Pharmacy Claims Database: Effects of Proximity to Criminal Anthrax Exposure in October 2001

Objective To identify, during the period of criminal anthrax exposures in October 2001, changes in utilization of ciprofloxacin and geographic patterns of any identified variations. Design Observational. Setting United States. Patients Individuals making prescription claims through a pharmacy benefits management company. Interventions Analysis of AdvancePCS pharmacy claims database. Main Outcome Measures Percentage change in ciprofloxacin utilization for 2000 and 2001 and, by locale, for September and October 2001. Results Utilization of ciprofloxacin tablets was significantly lower in calendar year 2001 than in calendar year 2000 (median decline, 10.3%) for all months except October, when utilization of ciprofloxacin increased 9.8%. During the period of anthrax exposures (October 2001 versus September 2001), affected geographic areas, including New York (an increase of 62.5%), some other Mid-Atlantic states, and Florida (28.5%), had some of the highest percentage increases in the rate of ciprofloxacin utilization. Conclusion Many Americans actively sought prophylaxis with ciprofloxacin during the course of the October 2001 anthrax attack and that utilization was higher in, but not limited to, locales with publicized cases of disease. Pharmacists, clinicians, and public health officials should note that such behavior may be expected in the event of a similar attack and should be familiar with current recommendations for the assessment and management of anthrax exposure.
On Deciding Whether Trend Surfaces of Progressively Higher Order Are Meaningful

In polynomial trend-surface analysis the only commonly used significance test is a comparison of the mean square associated with all terms of order ≤ k + 1with that for residual dispersion. Unless there is marked systematic association among deviations this test is basically irrelevant; once significance has been achieved at, say, order k , it is not likely to be lost by addition of terms of order greater than k, even if these terms do not reduce residual dispersion. A test of the mean square for variation associated with terms of order k + 1 only against residual dispersion at order k + 1 would be both more germane and more instructive. Examples are taken from the recent literature.
Possible Hemolytic Uremic Syndrome in Three Cats After Renal Transplantation and Cyclosporine Therapy

Objective— To describe the clinical history of 3 cats with possible hemolytic uremic syndrome (HUS) after renal transplantation. Study Design— This case series documents historical findings, physical examination findings, clinical pathologic features, necropsy and histopathologic findings of 3 cats with possible HUS. Results— Two cats had chronic renal failure; 1 cat had acute renal failure secondary to ethylene glycol toxicity. A renal transplant was performed in each of the 3 cats without obvious problems. Complications that would support a diagnosis of HUS, including anemia, thrombocytopenia, and azotemia occurred within 24 hours in 1 cat, within 8 days in a second cat, and 2 months after transplantation in the third cat. In 2 cats, HUS was likely secondary to cyclosporine immunosuppression. In the third cat, HUS may have been secondary to allograft rejection. Renal biopsies from all 3 cats were suggestive of HUS. Conclusion and Clinical Relevance— In human beings, HUS in transplant recipients may occur secondary to immunosuppressive drugs, vascular rejection, or recurrence of original disease. Graft loss occurred in all 3 cats in this study and the mortality rate was 100%. Clinicians caring for these patients need to be aware of this disorder because early recognition and treatment is critical in the management of post-transplant HUS.
Free boundary problems for the heat equation in which the moving interface coincides initially with the fixed face

A semi-infinite solid at the melting temperature 0 occupies the region 0 ⩽ x < ∞. At the fixed face x = 0 there is prescribed either (a) the temperature f(t) ⩾ 0 or (b) the heat flux f(t) directed into the solid, where f(t) is not identically zero in the vicinity of t = 0. There is a free boundary s(t) separating the liquid phase from the solid phase, and a temperature distribution u(x, t) in the liquid phase. We prove existence, uniqueness, and continuous dependence theorems for problems (a) and (b). Let F(t) be the integral, from 0 to t, of f(τ). Then we prove that for problem (a) s(t) behaves, in the vicinity of t = 0, essentially like the square root of F(t) while for problem (b) s(t) behaves essentially like F(t). We obtain also upper bounds for s′(t) for both problems. The existence theorems are proved as follows: the region 0 ⩽ x ⩽ a is taken to be liquid at the melting temperature and the region a < x < ∞ solid at the melting temperature. Problems (a) and (b) are known to have solutions uaand sa in this case which are bounded, equicontinuous families. By Arzela's theorem uniformly convergent subsequences can be extracted. These subsequences converge to the solutions of (a) and (b) for the case a = 0.
Extension of a Current Continuum-Level Material Model for Soil into the Low-Density Discrete-Particle Regime

In this article, an attempt is made to construct a soil-material model which can be used over a wide range of soil densities. To construct such a model, an existing purely continuum-type soil material model (used in the high-density regime), within which the granular structure of the soil is neglected, is combined with an existing discrete-type soil material model (used in the low-density regime) within which soil is treated as an assembly of interacting particles. In order to enable it to be used in conventional transient, nonlinear dynamics, and finite element analyses, the new soil material model is cast using a continuum-type framework. Thus, while in the low-density regime soil behavior is fully dominated by the discrete-type soil-material model, soil has been treated as a continuum constituent properties of which are governed by particle geometrical parameters and particle-particle interaction laws. To demonstrate the utility and fidelity of the new soil material model, a series of uniaxial strain computational tests involving rectangular, parallelepiped-shaped soil-slug normal impact onto a rigid, fixed, flat surface is carried out. While these tests are of a one-dimensional character, they are generally considered as being representative of the loading and deformation histories experienced by mine-blast-ejected soil during its impact with the target structure. The results obtained using the newly proposed soil material model, in the low-density regime, are found to be fully consistent with their discrete-particle modeling and simulation counterparts, suggesting that the new model can be used in transient nonlinear dynamics, finite element simulations involving low-density soil.