cssi/SciSciGPT-SciSciNet huggingface dataset:
The complexity of decision problems for finite-turn multicounter machines

Abstract We exhibit a large class of machines with polynomial time decidable containment and equivalence problems. The machines in the class accept more than the regular sets. We know of no other class (different from the finite-state acceptors) for which the containment and equivalence problems have been shown polynomially decidable. We also discuss the complexity of other decision problems.
LONG-RANGE PARTICLES FROM NUCLEAR FISSION

A measurement of the probability of emission of long-range particles, which are known to be predominantly alpha particles, made with a multiple ionization chamber gave the following results for spontaneous fission: ${\mathrm{Cf}}^{252}$, 299\ifmmode\pm\else\textpm\fi{}18; ${\mathrm{Cm}}^{242}$, 257\ifmmode\pm\else\textpm\fi{}17; ${\mathrm{Cm}}^{244}$, 314\ifmmode\pm\else\textpm\fi{}20; ${\mathrm{Pu}}^{240}$, 314\ifmmode\pm\else\textpm\fi{}20; and ${\mathrm{Pu}}^{242}$, 365\ifmmode\pm\else\textpm\fi{}29 fissions per long-range particle. The results for thermal neutron-induced fission of the following compound nuclei were: ${\mathrm{Pu}}^{240}$, 411\ifmmode\pm\else\textpm\fi{}26; ${\mathrm{Pu}}^{242}$, 440\ifmmode\pm\else\textpm\fi{}28; ${\mathrm{U}}^{236}$, 449\ifmmode\pm\else\textpm\fi{}30; and ${\mathrm{U}}^{234}$, 414\ifmmode\pm\else\textpm\fi{}26 fissions per long-range particle and for 1-Mev neutron-induced fission the results were: ${\mathrm{Pu}}^{240}$, 403\ifmmode\pm\else\textpm\fi{}25; ${\mathrm{U}}^{236}$, 534\ifmmode\pm\else\textpm\fi{}35; ${\mathrm{U}}^{235}$, 466\ifmmode\pm\else\textpm\fi{}30 fissions per long-range particle. These data indicate a trend of increasing probability of emission of long-range particles with increasing $\frac{{Z}^{2}}{A}$ values and decreasing probability with increasing excitation energy in a given nuclide. Present explanations of these apparently contradictory results seem inadequate.The energy spectra of long-range particles from spontaneous fission of ${\mathrm{Cf}}^{252}$ and thermal neutron-induced fission of ${\mathrm{U}}^{235}$ were observed with a CsI crystal scintillation apparatus and were found to be identical within the accuracy of observations, showing slightly askew bell-shaped distributions with maxima at 17\ifmmode\pm\else\textpm\fi{}1 Mev and end-point energies of 29\ifmmode\pm\else\textpm\fi{}1 Mev.
Paraconsistent logic programming

Abstract This paper makes two contributions. First, we give a semantics for sets of clauses of the syntactic form L 0 ⇍ L 1 &⋯& L n where each L i is a literal. We call such clauses generally Horn clauses. Any such endeavour has to give a coherent, formal treatment of inconsistency (in the sense of two-valued logic). Thus, as a second contribution, we give a robust semantics for generally Horn programs that allows us to “make sense” of sets of generally Horn clauses that are inconsistent (in the two-valued logic sense). This applies to the design of very large knowledge bases where inconsistent information is often present.
Well‐Being, Front and Center: A Note on the Sarkozy Report

The Sarkozy Report is a study commissioned by the French President on better ways to measure the level and progress of societal well-being than conventional economic indicators such as GDP. Despite being prepared by prominent economists—the commission was led by Joseph Stiglitz, Amartya Sen, and Jean-Paul Fitoussi—the Report rejects reliance on “production-oriented” measures of progress in favor of a broader array of quality-of-life indicators, some of them subjective, and measures of the sustainability of well-being into the future. These multiple dimensions of well-being, it argues, should be used in policy decisions and welfare evaluations. The views expressed in the Report may portend a sea-change in the way economists think about the benefits of economic growth.
A trial of nebulized magnesium sulfate to reverse bronchospasm in asthmatic patients.

Study objective: To test the hypothesis that nebulized magnesium sulfate reverses methacholine-induced bronchospasm in asthmatic patients. Design: Randomized, double-blind, crossover clinical trial. Setting: Center for Asthma and Allergic Diseases, Children's Hospital of Pittsburgh. Type of participants: Ten patients who were 21 to 37 years old and had stable asthma. Interventions: Patients withheld asthma medications for 24 hours before each study day. Patients with baseline forced expiratory volume in one second (FEV 1 ) of less than 80% were excluded. All subjects underwent bronchial methacholine challenge to produce bronchospasm. They then received one of three different nebulized treatments: 2.5 mg albuterol in 3 mL saline, 3 mL magnesium sulfate (268 mmoL/L, pH 6.4), or 3 mL normal saline. Patients repeated spirometry 15 minutes after completing the study drug and then received albuterol by metered-dose inhaler. Spirometry was repeated after the metered-dose inhaler. Each patient made three separate visits to receive each of the three medications. Measurements and results: Methacholine reduced each patient's FEV 1 by at least 20% at each testing session. Post-methacholine treatment with nebulized albuterol improved FEV 1 by a mean of 56% (SD, 19.6%). Nebulized normal saline led to a mean increase in FEV 1 of 29% (SD, 26.5%). Nebulized magnesium sulfate improved FEV 1 by a mean of 12% (SD,12.0%) ( P = .054 by paired t -test compared with normal saline). Conclusion: Nebulized magnesium sulfate has a minimal bronchodilatory effect in asthmatic patients with methacholine-induced bronchoconstriction. Responsiveness to magnesium sulfate may be dependent on the mechanism of induction of bronchospasm, and there probably is no role for nebulized magnesium sulfate in the treatment of acute bronchospasm due to cholinergic stimulation.
The detection of unresolved targets using the Hough Transform

Clutter resulting from drift and vibration in a sensor line-of-sight and time-varying components in the background can seriously hinder the detection of faint, unresolved (i.e., point) targets moving against a background. These targets, however, produce well-defined patterns of motion referred to as tracks, whereas the effects of noise and clutter are more random. Frame-to-frame differencing can be used to reject clutter and enhance the detection of moving targets. These difference frames can then be combined recursively to form target tracks, The tracks of nonmaneuvering (i.e., constant velocity) targets appear as llne segments that can be detected using the Hough transform. In addition, the current position and heading of a target can be determined using a technique based on matched filtering. An example demonstrating the performance of this technique is also presented.
Detection of Cellular Adhesion Molecules in Inflamed Human Corneas

Purpose: The expression of cellular adhesion molecules in 31 penetrating keratoplasty specimens from a broad range of corneal inflammatory diseases was studied using monoclonal antibodies and an immunoperoxidase technique. Methods: Corneas were divided into noninflamed, mild to moderately inflamed, and severely inflamed groups based on histologic findings. The panel of adhesion molecules studied included HLA-ABC, HLA-DR, CD3, LFA-1, MAC-1, ICAM-1, PECAM-1, VCAM1, and E-selectin-1. Results: The adhesion molecules ICAM-1, HLA-DR, PECAM-1, CD3, VCAM-1, LFA-1, and MAC-1 were selectively expressed in areas of corneal inflammation. In general, HLA-DR and intercellular adhesion molecule ICAM-1 were co-expressed in similar regions. PECAM-1 was restricted to zones of marked inflammation and vascularization. E-selectin-1 was detected only in the stroma of a graft melt in a patient with active ocular cicatricial pemphigoid, and may reflect a primary regulatory dysfunction in this disorder. The ICAM-1 ligand was, in general, more diffusely distributed than its receptor LFA-1, a beta-2 integrin found on leukocyte cell membranes. The localization of the integrin MAC-1, present on macrophages, neutrophils, and some lymphocytes, did not always parallel the staining pattern of ICAM-1, suggesting promiscuity in its binding to other ligands besides ICAM-1. Conclusions: Adhesion molecules are detected readily at sites of corneal inflammation and may play a critical role in facilitating the recruitment of immune regulatory cells to these areas. Future efforts to block or modulate the expression of intercellular adhesion molecules may provide new therapeutic options in the treatment of corneal inflammatory diseases.
Linking Gas Fractions to Bimodalities in Galaxy Properties

Galaxies over 4 decades in stellar mass are shown to obey a strong correlation between u - K colors and atomic-gas-to-stellar mass ratios (G/S), using stellar mass-to-light ratios derived from optical colors. The correlation holds for G/S ranging from nearly 10 : 1 to 1 : 100 for a sample obtained by merging the SDSS DR2, 2MASS, and HyperLeda H I catalogs. This result implies that u - K colors can be calibrated to provide photometric gas fractions for statistical applications. Here this technique is applied to a sample of ~35,000 SDSS-2MASS galaxies to examine the relationship of gas fractions to observed bimodalities in galaxy properties as a function of color and stellar mass. The recently identified transition in galaxy properties at stellar masses ~(2-3) × 1010 M☉ corresponds to a shift in gas richness, dividing low-mass late-type galaxies with G/S ~ 1 : 1 from high-mass galaxies with intermediate-to-low G/S. Early-type galaxies below the transition mass also show elevated G/S, consistent with formation scenarios involving mergers of low-mass gas-rich systems and/or cold-mode gas accretion.
A new CP violating observable for the LHC

We study a new type of CP violating observable that arises in three body decays that are dominated by an intermediate resonance. If two interfering diagrams exist with different orderings of final state particles, the required CP-even phase arises due to the different virtualities of the resonance in each of the two diagrams. This method can be an important tool for accessing new CP phases at the LHC and future colliders.
Fluid-flow of a row of jets in crossflow - A numerical study

A detailed computer-visualized flow field of a row of jets in a confined crossflow is presented. The Reynolds averaged Navier-Stokes equations are solved using a finite volume method that incorporates a partial differential equation for incremental pressure to obtain a divergence-free flow field. The turbulence is described by a multiple-time-scale turbulence model. The computational domain includes the upstream region of the circular jet so that the interaction between the jet and the crossflow is simulated accurately. It is shown that the row of jets in the crossflow is characterized by a highly complex flow field that includes a horse-shoe vortex and two helical vortices whose secondary velocity components are co-rotating in space. It is also shown that the horse-shoe vortex is a ring of reversed flows located along the circumference of the jet exit.
Trade and Income Convergence: Sorting Out the Causality

This paper studies the linkage between internationa l trade and income convergence across countries. Different theories of fer conflicting predictions regarding how they might affect each other. In the existing e mpirical literature estimating the trade impact on income convergence, a long-lasting problem is the reverse causality from income convergence to trade. This paper provides a disaggregated bilateral trade data analysis to solve this problem. The results show th at the reverse causality from income convergence to trade exists in differentiated produ ct sectors, but not in homogeneous product sectors. Trade in homogeneous sectors reduces the income gaps among trade partners, but it is not significantly affected by t heir income difference. Therefore the negative effect of trade in homogeneous sectors on income gap is free from the reverse causality problem. It can be taken as the pure evid ence of trade-induced income convergence. This result is robust to various econo metric methods.
Possibility to disentangle anisotropic flow, flow fluctuation, and nonflow assuming Gaussian fluctuations

We suggest the possibility to disentangle anisotropic flow, flow fluctuation, and nonflow using two-, four-, and six-particle azimuthal moments assuming Gaussian fluctuations. We show that such disentanglement is possible when the flow fluctuations are large, comparable to the average flow magnitude. When fluctuations are small, the disentanglement becomes difficult. We verify our results with a toy-model Monte Carlo simulation.
Phosphonomethylation of cyclohexene oxides

The tradeoff between synthetic directness and regioselectivity during oxirane ring opening is examined for two strategies used to phosphonomethylate cyclohexene oxide and substituted cyclohexene oxides derived from quinic acid and myo-inositol. Direct phosphonomethylation of the cyclohexene oxides utilizes diisopropyl lithiomethanephosphonate ((C 3 H 7 O) 2 P(O)CH 2 Li) in combination with boron trifluoride. Another more indirect route to phosphonomethylation begins with reaction of the cycloherene oxides with (lithiomethyl)dimesitylborane (Mes 2 BCH 2 Li). A both reactions, boron plays a key role as either a Lewis acid during opening of the oxirane (diisopropyl lithiomethane-phosphonate/boron trifluoride) or as a stabilizer of an adjacent carbanion in the attacking nucleophile [(lithiomethyl)dimesitylborane]. Regioselectivities for oxirane ring opening using diisopropyl lithiomethanephosphonate/ boron trifluoride can be quite modest. By contrast, oxirane ring openings employing (lithiomethyl)dimesitylborane are uniform in the high degree of regioselectivity which is achieved. Factors which might influence the observed regioselectivities during nucleophilic attack on the cyclohexene oxides are also discussed
Conformal coordinates associated with uniformly accelerated motion

Specific problems in the theory of relativity are often simplified by an appropriate choice of the coordinate system. Restricted conformal coordinates provide an especially simple analysis of motion with uniform acceleration, known as hyperbolic motion. Conformal coordinates x', t' may be obtained from Cartesian coordinates x, t by the transformation x'+ct'=F(x+ct) and x'-ct'=G(x-ct), where c is the velocity of light. A variable motion of the x' system is determined by the choice of the functions F and G.
A new ultrasonic imaging system using time delay spectrometry.

A new method of forming a visual image by ultrasound is described. A shadowgraphic transmission image similar to an X-ray radiograph is produced by the application of a technique known as Time Delay Spectrometry. The system uses a repetitive frequency sweep with a linear relationship between frequency and time and the transmitting and receiving crystal are scanned in raster fashion about the subject. By electronic processing, an image may be built up which represents the energy transmitted through the specimen with a given time delay. An intensity modulated picture encompassing the full shades-of-gray capability of the recording system can be produced. A second type of image showing transmission time through the specimen may also be formed. Brightness changes in the displayed image in this case correspond to changes in the ultrasonic transmission time through the specimen.
Bremsstrahlung radiation effects in rare earth permanent magnets

Advances in rare earth permanent magnet (REPM) technology have made possible new applications. Two such applications are the use of permanent magnetic lenses for accelerator and beam transport systems and the expanding use in undulators and wigglers of synchrotron radiation and free electron laser systems. Both applications involve potential exposure of REPM's to high radiation fields. We have investigated the radiation hardness of several different varieties of REPM's up to 2 gigarads of absorbed dose from a mixed electron-photon (bremsstrahlung) field. Sm/sub 2/Co/sub 17/, Nd/sub 2/Fe/sub 14/B and an experimental REPM, Pr/sub 15/Fe/sub 79/B/sub 6/, from several different manufacturers have been investigated. Of the samples irradiated, Sm/sub 2/Co/sub 17/ proved to be the most resistant to bremsstrahlung radiation. However, details of manufacturing techniques produced significantly different results. We observed that REPM's of nominally identical stoichiometric composition from different manufacturers did not show the same rate of remanence loss. We present details of our experiment and absorbed dose modeling and a summary of radiation effects measurements of which we are aware. Our study of these radiation damage experiments lead us to the empirical observation that the order of radiation hardness is Sm/sub 2/Co/sub 17/, SmCo/sub 5/ and Nd/sub 2/Fe/sub 14/B, regardlessmore » of the source of radiation, i.e., gammas, electrons, protons or neutrons. 8 refs., 2 figs., 4 tabs.« less
Investing in Soils: Field Bunds and Microcatchments in Burkina Faso

This research uses field-level data from Burkina Faso to ask what determines farmers' investment in two well-known soil and water conservation techniques: field bunds (barriers to soil and water runoff), and microcatchments (small holes in which seeds and fertilizers are placed). Survey data for 1993 and 1994 are used to estimate Tobit functions, compute elasticities of adoption and intensity of use, perform robustness tests and estimate alternative models. Controlling for land and labor abundance and other factors we find that those who have more ownership rights over farmland, and who do more controlled feeding of livestock, tend to invest more in both technologies. The result suggests that responding to land scarcity with clearer property rights over cropland and pasture could help promote investment in soil conservation, and raise the productivity of factors applied to land.
Measurement of the Doppler Width of the λ 5577 Line in the Night Sky

A DETERMINATION of the Doppler width of the λ 5577 oxygen line in the night sky spectrum was attempted by Babcock1; but his instrumentation permitted only an estimate of the upper limit of this width and hence of the temperature of the emitting layer. We wish to report here preliminary results of a new study of the λ 5577 line using improved interferometric apparatus.
Carbonyl directed epoxidation in γ,δ-unsaturated acid derivatives

Abstract The epoxidation of cyclopent-2-ene and cyclohex-2-ene acetic acid derivatives with MCPBA provided predominately the syn epoxide.
Tracking control of nonlinear systems with bounded controls and control rates

Abstract The problem of tracking control of a class of nonlinear systems subject to control and control-rate constraints is considered. A continuous-time predictive control approach is used to derive the nonlinear constrained control law. Asymptotically stable tracking is ensured in the absence of saturation. The control and control-rate constraints are guaranteed to be strictly satisfied by the control law. An example is given to demonstrate the effectiveness of the method
Specimen Geometry Effects on High-Strain-Rate Testing of Graphite/Epoxy Composites

Numerous papers have been published that include high-strain-rate experimental data obtained from Split Hopkinson Pressure Bar (SHPB) tests. There have been no standardized test specimens with differing dimensions and geometry. For this reason, it can be difficult to compare results of tests performed by other researchers. The SHPB facility was used in this study to determine if specimen geometry has an effect on the results of high-strain-rate compression tests. The material used in all of the tests is a unidirectional IM7/8551-7 graphite/epoxy composite. The experiments discussed herein show the effect of varying the length-to-diameter (L/D, or aspect) ratio of the specimen, as well as the effect of changing from the more typical cylindrical to a square/rectangular specimen geometry. The L/D study examined 84 cylindrical specimens with L/Ds from 0.5 to 2.0, with D = 0.261 in., and tested in both the 1 and 2 directions. The geometry study used 42 square/rectangular specimens and tested in the 1, 2, and 3 directions. The results of both studies are compared, and no statistically significant effect of either L/D or geometry could be found.
Food security policy in a stochastic world.

Abstract Food security may be increased by variance-reducing strategies, by food aid, or by development strategies. This paper uses a Korea CGE model, subjected to random fluctuation in world-prices and domestic food productivity, to evaluate these policies. We find that poverty- reducing development strategies are the most food-security strategies.
Oblique Pursuits for Compressed Sensing

Compressed sensing is a new data acquisition paradigm enabling universal, simple, and reduced-cost acquisition, by exploiting a sparse signal model. Most notably, recovery of the signal by computationally efficient algorithms is guaranteed for certain randomized acquisition systems. However, there is a discrepancy between the theoretical guarantees and practical applications. In applications, including Fourier imaging in various modalities, the measurements are acquired by inner products with vectors selected randomly (sampled) from a frame. Currently available guarantees are derived using the so-called restricted isometry property (RIP), which has only been shown to hold under ideal assumptions. For example, the sampling from the frame needs to be independent and identically distributed with the uniform distribution, and the frame must be tight. In practice though, one or more of the ideal assumptions are typically violated and none of the RIP-based guarantees applies. Motivated by this discrepancy, we propose two related changes in the existing framework: 1) a generalized RIP called the restricted biorthogonality property (RBOP); and 2) correspondingly modified versions of existing greedy pursuit algorithms, which we call oblique pursuits. Oblique pursuits are guaranteed using the RBOP without requiring ideal assumptions; hence, the guarantees apply to practical acquisition schemes. Numerical results show that oblique pursuits also perform competitively with, or sometimes better than their conventional counterparts.
A new and easy-to-use measure of literacy, its axiomatic properties and an application

It can be argued that just as there are different kinds of literacy, there are different kinds of illiteracy. A “proximate illiterate,” i.e. an illiterate who has easy access to a literate person, is clearly better off than someone without such access. The existing literature that takes account of these differences (1) defines an illiterate person to be a proximate illiterate if he or she lives in a household with at least one literate person and (2) derives new measures of literacy which typically exceed the standard literacy rate. The latter risks generating policy complacency. The aim of this paper is to suggest a measure of literacy that is not limited by (1) and (2). The measure is axiomatically characterized and its use is illustrated with a numerical exercise for the provinces of South Africa.
Miracle at the Gepner point

Abstract A four-point function of E 6 singlets, of interest in elucidating the moduli space of (0,2) deformations of the quintic string vacuum, is computed using analytic and numerical methods. The conformal field theory amplitude satisfies the requisite selection rules and monodromy conditions, but the integrated string amplitude vanishes. Together with selection rules coming from the spacetime R-symmetry [1], this demonstrates the flatness of the gauge-singlet spacetime superpotential through fourth order. Relevance to the more general program of determining the (0,2) moduli space and superpotential is discussed.
Evaluation of Portable Optical Property Measurement Equipment for Solar Selective Surfaces

The operation and accuracy of portable optical measurement equipment for determining the solar absorptance, αs , and emittance, e, of solar selective surfaces are presented. The optical equipment includes a Gier Dunkle Solar Reflectometer (Model MS-251) and a Willey Alpha Meter (Model 2150) for αs measurements and a Gier Dunkle Infrared Reflectometer (Model DB-100) and a Willey Ambient Emissometer (Model 2158) for e measurements. The accuracy of the MS-251 for measurements of αs for electrodeposited black chrome coatings was determined to be better than ±0.03 absorptance units. For the same coatings, the Willey Alpha Meter accuracy was limited by deviations up to 0.11 absorptance units. The accuracy of the Gier Dunkle Infrared Reflectometer for e(100°C) measurements is better than ±0.02 emittance units. Values for e(100°C) determined with the Willey Emissometer using black chrome coatings are higher than the actual 100°C emittance. However, since the relationship is linear, the correct emittance can be calculated by multiplication by a constant factor.
The effect of armed conflict on accumulation of schooling: Results from Tajikistan

Abstract This paper uses differences in regional and temporal exposure to the 1992–1998 armed conflict in Tajikistan to study the effect of violent conflict on schooling outcomes. Data on the past damage to a household's residences from the 1999 Tajik Living Standards Survey is used as well as data on the events during the conflict within a conceptual framework that controls for important individual, household and community characteristics. Girls who were of school age during the conflict and lived in affected regions were less likely to complete their mandatory schooling than girls of the same age who lived in the regions relatively unaffected by conflict. The results also indicate that exposure to violent conflict had a large and statistically significant negative effect on the enrollment of girls. No effect of regional and household conflict exposure on education of boys was found. The results are robust to community and household fixed effects, selection into violence and migration.
Muonic x-ray laser assisted by catalyzed fusion of deuterium and tritium

The possibility of an X-ray laser by irradiation of muon beams on a thin rod of deuterium-tritium mixture is discussed. The excited state of dt μ-mesomolecules ( J , v ) = (1, 0) can be induced to make radiative chain transitions with photon energy of 90 eV to the ground state (0, 0), evacuated by fusion.
First jump of microgel; actuation speed enhancement by elastic instability

Swelling-induced snap-buckling in a 3D micro hydrogel device, inspired by the insect-trapping action of Venus flytrap, makes it possible to generate astonishingly fast actuation. We demonstrate that elastic energy is effectively stored and quickly released from the device by incorporating elastic instability. Utilizing its rapid actuation speed, the device can even jump by itself upon wetting.
Conditionally Cycle-Free Generalized Tanner Graphs: Theory and Application to High-Rate Serially Concatenated Codes

Generalized Tanner graphs have been implicitly studied by a number of authors under the rubric of generalized parity-check matrices. This work considers the conditioning of binary hidden variables in such models in order to break all cycles and thus derive optimal soft-in soft-out (SISO) decoding algorithms. Conditionally cycle-free generalized Tanner graphs are shown to imply optimal SISO decoding algorithms for the first order Reed-Muller codes and their duals - the extended Hamming codes - which are substantially less complex than conventional bit-level trellis decoding. The study of low-complexity optimal SISO decoding algorithms for the family of extended Hamming codes is practically motivated. Specifically, it is shown that exended Hamming codes offer an attractive alternative to high- rate convolutional codes in terms of both performance and complexity for use in very high-rate, very low-floor, serially concatenated coding schemes.
Dicyanoketene: Flash Vacuum Thermolysis of Alkyl Dicyanoacetates†

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1983, 193. DOI:10.1002/anie.198301930
Synthesis of polyphenylene derivatives by thermolysis of enediynes and dialkynylaromatic monomers

Abstract Described are the syntheses of substituted enediynes and dialkynylaromatics using Pd- or Pd Cu -catalyzed cross coupling procedures. The products were then thermalized to afford the corresponding poly(p-phenylene)s, poly(1,4-naphthalene)s, poly(benzo[c]thiophene)s, and poly(dibenzothiophene)s. Fifteen examples are provided that show the scope of the polymerization process based upon substituent patterns and cyclization moieties. The superb thermal resiliency of the newly derived polymers is demonstrated using thermogravimetric analysis. The polymer structure was generally confirmed using IR data correlations to small molecules that resembled the polymers' repeat unit structure. Radical trapping of dimeric intermediates, that were analyzed by GCMS, further substantiated the proposed mechanistic route. The step-growth polymerization pattern was determined by monitoring the degree of monomer consumption versus the polymer molecular weight.
A5TaAs4Tl2 (A = Rb, K). Transition-Metal Zintl Phases with a Novel Complex Ion: Synthesis, Structure, and Bonding

Reactions of the Rb−Tl−As system near 500 °C in tantalum containers always lead to the formation of Rb5TaAs4Tl2 because of reactions with the container wall. On-stoichiometry reactions of these three elements in Ta, or of the four components in SiO2, afford the pure compound. Rb5TaAs4Tl2 crystallizes in orthorhombic system, space group Pnma (No. 62), Z = 4, a = 19.196(5) A, b = 11.104(3) A, c = 7.894(4) A. The isostructural K5TaAs4Tl2 also exists. The main structural feature is the closed-shell polyanion TaAs4Tl25- which can be viewed as the result of a reaction of a TaAs47- tetrahedron with two Tl+ so as to bridge opposed edges of the former. EHMO calculations for TaAs47- (Td) and TaAs4Tl25- (D2h) demonstrate the character of the bonding of Tl s and p to the electron-rich As. Two kinds of multicentered bonds are evident: π⊥ and σ plus π∥ in the plane of the TlAs2Ta portions and 5c−4e d−p bonds within TaAs4.
Nitroarene products from the gas‐phase reactions of volatile polycyclic aromatic hydrocarbons with the OH radical and N2O5

The nitroarene products of the gas-phase reactions of acenaphthylene, acenaphthene, phenanthrene, and anthracene-d10 with N2O5 and the OH radical (in the presence of NOx) are reported. The calculated atmospheric lifetimes of these polycyclic aromatic hydrocarbons (PAH), as well as those of naphthalene, 1- and 2-methylnaphthalene, biphenyl, fluoranthene, pyrene, and acephenanthrylene, show that reaction with the OH radical is the dominant loss process for these PAH, with the exception of acenaphthylene, acenaphthene, and acephenanthrylene which contain an external cyclopenta-fused ring. For these latter PAH, reaction with the NO3 radical, and for acenaphthylene and acephenanthrylene reaction with O3, are also expected to be important atmospheric loss processes. The nitroarenes observed as products of the atmospherically-important gas-phase reactions of the PAH in environmental chamber studies are compared with the nitroarenes measured in ambient air samples collected in California. It is concluded that although nitroarenes are formed in low yields (≲5%) from the OH radical-initiated reactions of the PAH, atmospheric formation of nitroarenes may contribute significantly to ambient nitroarene concentrations.
The spectroscopy of molecular reaction intermediates trapped in the solid rare gases

The trapping of neutral and electrically charged molecular reaction intermediates in the solid rare gases and the characterization of these intermediates by vibrational and electronic spectroscopy are surveyed. Spectral data for reaction intermediates trapped in solid neon and argon are compared with the corresponding data obtained from gas phase studies and from quantum chemical calculations. Emphasis is placed on recent progress, including the production, stabilization, and spectroscopic study of highly reactive small molecular ions and the use of ab initio and density functional calculations for the identification of reaction intermediates.
Semiclassical approximation in Batalin-Vilkovisky formalism

The geometry of supermanifolds provided with aQ-structure (i.e. with an odd vector fieldQ satisfying {Q, Q}=0), aP-structure (odd symplectic structure) and anS-structure (volume element) or with various combinations of these structures is studied. The results are applied to the analysis of the Batalin-Vilkovisky approach to the quantization of gauge theories. In particular the semiclassical approximation in this approach is expressed in terms of Reidemeister torsion.
Conductance fluctuations near the two-dimensional metal–insulator transition

Abstract Measurements of conductance G on short, wide, high-mobility Si-MOSFETs reveal both a two-dimensional metal–insulator transition (MIT) at moderate temperatures (1 T T n s ) controlled by gate voltage ( V g ) and magnetic field B near the MIT. Fourier analysis of the low-temperature fluctuations reveals several fluctuation scales in V g that vary non-monotonically near the MIT. At higher temperatures, G ( V g , B ) is similar to large FETs and exhibits a MIT. All of the observations support the suggestion that the MIT is driven by Coulomb interactions among the carriers.
Quantum Algorithms for Learning Symmetric Juntas via the Adversary Bound

In this paper, we study the following variant of the junta learning problem. We are given oracle access to a Boolean function f on n variables that only depends on k variables, and, when restricted to them, equals some predefined function h. The task is to identify the variables the function depends on.When h is the XOR or the OR function, this gives a restricted variant of the Bernstein---Vazirani or the combinatorial group testing problem, respectively. We analyze the general case using the adversary bound and give an alternative formulation for the quantum query complexity of this problem. We construct optimal quantum query algorithms for the cases when h is the OR function (complexity is $${\Theta(\sqrt{k})}$$?(k)) or the exact-half function (complexity is $${\Theta(k^{1/4})}$$?(k1/4)). The first algorithm resolves an open problem from Ambainis & Montanaro (Quantum Inf Comput 14(5&6): 439---453, 2014). For the case when h is the majority function, we prove an upper bound of $${O(k^{1/4})}$$O(k1/4). All these algorithms can be made exact. We obtain a quartic improvement when compared to the randomized complexity (if h is the exact-half or the majority function), and a quadratic one when compared to the non-adaptive quantum complexity (for all functions considered in the paper).
The association of PM2.5 with full term low birth weight at different spatial scales

There is interest in determining the relationship between fine particulate matter air pollution and various health outcomes, including birth outcomes such as term low birth weight. Previous studies have come to different conclusions. In this study we consider whether the effect may vary by location and gestational period. We also compare results when using different spatial resolutions for the air concentration estimates. Among the seven states considered, New Jersey and New York had the highest PM2.5 levels (average full gestation period exposures of 13 µg/m(3)) and the largest rate of low birth weight births (2.6 and 2.8%, respectively); conversely Utah and Minnesota had the lowest PM2.5 levels (9 µg/m(3)) and the lowest rates of low birth weight births (2.1 and1.9%, respectively). There is an association between PM2.5 exposure and low birth weight in New York for the full gestation period and all three trimesters, in Minnesota for the full gestation period and the first and third trimesters, and in New Jersey for the full gestation period and the first trimester. When we pooled the data across states, the OR for the full gestation period was 1.030 (95% CI: 1.022-1.037) and it was highest for the first trimester (OR 1.018; CI: 1.013-1.022) and decreasing during the later trimesters. When we used a finer spatial resolution, the strengths of the associations tended to diminish and were no longer statistically significant. We consider reasons why these differences may occur and their implications for evaluating the effects of PM2.5 on birth outcomes.
Oligomeric Rare-Earth-Metal Halide Clusters. Three Structures Built of (Y16Z4)Br36 Units (Z = Ru, Ir)

Suitable reactions in sealed Nb tubing at 850-950 {degrees}C gave good yields of a family of oligomeric cluster phases that were characterized by single-crystal X-ray diffraction means. The basic Y{sub 16}Z{sub 4} units ({approximately}{bar 4} symmetry) can be derived from 2+2 condensation of centered Y{sub 6}Br{sub 12}Z-type clusters or as tetracapped truncated tetrahedra Y{sub 16} that are centered by a large tetrahedral Z{sub 4}. These are surrounded by 36 bromine atoms which bridge edges or cap faces of the Y{sub 16}Z{sub 4} nuclei and, in part, bridge to metal atoms in other clusters. The principal bonding appears to be Y-Z and Y-Br, with weaker Y-Y ({bar d} {approximately} 3.70 {angstrom}) and negligible Z-Z interactions. The phase Y{sub 16}Br{sub 20}Ru{sub 4} (P4{sub 2}/nnm, Z = 2; a = 11.662(1) {angstrom}, c = 16.992 (2) {angstrom}) is isostructural with Y{sub 16}I{sub 20}Ru{sub 4} and with the new Sc{sub 16-} Br{sub 20}Z{sub 4} (Z = Fe, Os). Syntheses only in the presence of Ir and ABr-YBr{sub 3} fluxes (A = K-Cs) produce Y{sub 16-} Br{sub 24}Ir{sub 4} (Fddd, Z = 8; a = 11.718(3) {angstrom}, b = 22.361(7) {angstrom}, c = 44.702(2) {angstrom}), in which the electron-richer Ir interstitials are compensated by fourmore » additional bromine atoms and altered bridging between macroclusters. Larger amounts of YBr{sub 3} yield a third example, Y{sub 20}Br{sub 36}Ir{sub 4} (Y{sub 16}Br{sub 24}Ir{sub 4}{center_dot}4YBr{sub 3}, I4{sub 1}a, Z = 4; a = 12.699(1) {angstrom}, c = 45.11- (1){angstrom}). Here infinite zigzag chains of YBr{sub 6/2} octahedra that share cis edges lie between and bridge to the Y{sub 16}Ir{sub 4} clusters. All of these phases contain 60-electron, closed-shell macroclusters. Y{sub 16}Br{sub 20}Ru{sub 4} and Y{sub 20}Br{sub 36}ir{sub 4} were found to exhibit temperature-independent (Van Vleck) paramagnetism with values typical of those found for other rare-earth-metal, zirconium, niobium, and tantalum cluster halides.« less
H-ras and K-ras mutations in soft tissue sarcoma: Comparative studies of sarcomas from Korean and American patients

BACKGROUND The authors' recent investigation of Korean patients with sarcoma has suggested that ras gene activation may play a role in oncogenesis. The authors attempted to extend the mutation analysis to sarcomas in American patients to determine whether there were racial or geographic factors relevant to the initiation or progression of sarcoma. METHODS H-ras and K-ras genes were examined in sarcomas obtained from patients in the midwestern U. S. using the polymerase chain reaction technique and direct automated sequencing analysis. Tumors studied included 29 malignant fibrous histiocytomas, 7 liposarcomas, 5 rhabdomyosarcomas, and 9 leiomyosarcomas. RESULTS Of the 50 sarcomas evaluated, only 1 (2%) definable mutation was found; a GGC to AGC transition at codon 12 of H-ras was found in a rhabdomyosarcoma. None of the patients had a K-ras mutation. The rates of incidence of ras point mutations in these samples were much lower (H-ras: 2%; 95% confidence interval [95% CI], 0-11.5% and K-ras: 0%) than described for both genes in Korean studies (H-ras: 16%; 95% CI, 5.2-26.8% and K-ras: 44%; 95% CI, 29.5-58.5%). CONCLUSIONS Although the reason for this discrepancy is not clear, there were no major differences found in histology or clinical stages. Based on this study of 50 sarcoma samples from American patients and the authors' previous study of 45 Korean tumor samples, the authors conclude that differing genetic and/or environmental mechanisms can affect sarcoma development or progression. Mutation of the H-ras and K-ras genes appears to be uncommon in sarcomas occurring in American patients, suggesting that the activation by point mutations of the H-ras and K-ras genes does not play a significant role in the pathogenesis or progression of sarcoma in these patients. Cancer 1999;86:58–63. © 1999 American Cancer Society.
Seiberg{Witten Invariants and Pseudo-Holomorphic Subvarieties for Self-Dual, Harmonic 2{Forms

A smooth, compact 4{manifold with a Riemannian metric and b 2+ 1h as a non-trivial, closed, self-dual 2{form. If the metric is generic, then the zero set of this form is a disjoint union of circles. On the complement of this zero set, the symplectic form and the metric dene an almost complex structure; and the latter can be used to dene pseudo-holomorphic submanifolds and subvarieties. The main theorem in this paper asserts that if the 4{manifold has a non zero Seiberg{Witten invariant, then the zero set of any given self-dual harmonic 2{form is the boundary of a pseudo-holomorphic subvariety in its complement.
Hysteresis and competition between disorder and crystallization in sheared and vibrated granular flow.

Experiments on spherical particles in a 3D annular shear cell vibrated from below and sheared from above show a hysteretic freezing or melting transition. Under sufficient vibration a crystallized state is observed, which can be melted by sufficient shear. The critical line for this transition coincides with equal kinetic energies for vibration and shear. The force distribution is double peaked in the crystalline state and single peaked with an approximately exponential tail in the disordered state. Continuous relations between pressure and volume (with $dP/dVg0$) exist for a continuum of partially and/or intermittently melted states over a range of parameters.
How hard is mechanism elucidation in catalysis? Combinatorial analysis of C1 chemistry

Most chemical reactions occur over multiple steps whose identity is elucidated by experiment, yielding a reaction mechanism. Knowledge of cognitive science suggests that mechanism elucidation can be viewed as a knowledge-guided search within a combinatorial space. The MECHEM computer program searches this space comprehensively for the simplest plausible mechanisms. We use MECHEM to find mechanisms for Fischer−Tropsch chemistry and CO2 re-forming of methane, both heterogeneous catalytic reactions of current importance. The results reveal hundreds of equally simple mechanisms consistent with evidence. Hence, mechanism elucidation in catalysis is a much harder problem than is ordinarily realized.
Mining Metrics for Buried Treasure

The same but different: That might describe two metrics. On the surface CLASSI may show two metrics are locally equivalent, but buried beneath may be a wealth of further structure. This was beautifully described in a paper by Malcolm MacCallum in 1998. Here I will illustrate the effect with two flat metrics — one describing ordinary Minkowski spacetime and the other describing a threeparameter family of Gal'tsov-Letelier-Tod spacetimes. I will dig out the beautiful hidden classical singularity structure of the latter (a structure first noticed by Tod in 1994) and then show how quantum considerations can illuminate the riches. I will then discuss how quantum structure can help us understand classical singularities and metric parameters in a variety of exact solutions mined from the Exact Solutions book.
Characterization of Hot Isostatically Pressed Bi─Sr─Ca─Cu─O as a Function of Consolidation Variables

Fully dense, bulk Bi2Sr1.7CaCu2Ox (2212) superconductor pellets were made by hot isostatic pressing in an inert atmosphere. Electron microscopy revealed that rotation and bending of the platelike 2212 grains were responsible for much of the densification. Under processing conditions of 825°C and 105 MPa, dense pellets were obtained in 15 min. Many dislocations, planar faults, and, perhaps, intergrowths of the Bi2Sr2CuOx phase were produced during pressing. The dislocations were largely present in subgrain boundaries when the pressing times were increased to 45-120 min.
The effects of time-compressed instruction and redundancy on learning and learners' perceptions of cognitive load

Can increasing the speed of audio narration in multimedia instruction decrease training time and still maintain learning? The purpose of this study was to examine the effects of time-compressed instruction and redundancy on learning and learners' perceptions of cognitive load. 154 university students were placed into conditions that consisted of time-compression (0%, 25%, or 50%) and redundancy (redundant text and narration or narration only). Participants were presented with multimedia instruction on the human heart and its parts then given factual and problem solving knowledge tests, a cognitive load measure, and a review behavior (back and replay buttons) measure. Results of the study indicated that participants who were presented 0% and 25% compression obtained similar scores on both the factual and problem solving measures. Additionally, they indicated similar levels of cognitive load. Participants who were presented redundant instruction were not able to perform as well as participants presented non-redundant instruction.
Repetition blindness is immune to the central bottleneck

Theattentional blink (AB) andrepetition blindness (RB) phenomena refer to subjects’ impaired ability to detect the second of two different (AB) or identical (RB) target stimuli in a rapid serial visual presentation stream if they appear within 500 msec of one another. Despite the fact that the AB reveals a failure of conscious visual perception, it is at least partly due to limitations at central stages of information processing. Do all attentional limits to conscious perception have their locus at this central bottleneck? To address this question, here we investigated whether RB is affected by online response selection, a cognitive operation that requires central processing. The results indicate that, unlike the AB, RB does not result from central resource limitations. Evidently, temporal attentional limits to conscious perception can occur at multiple stages of information processing.
Pauli-Villars regularization of globally supersymmetric theories

It is shown that the one-loop ultraviolet divergences in renormalizable supersymmetric theories can be regulated by the introduction of heavy Pauli-Villars chiral supermultiplets, provided the generators of the gauge group are traceless in the matter representation. The procedure is extended to include supersymmetric gauged nonlinear sigma models.
Bonneville Power Administration's 1100-kV Direct Current Test Project: I - Measurements and Instrumentation

Methods of measurement and analysis of components of a five-mile extra-high-voltage direct-current test line and associated facilities are described. This paper presents new methods of recording and analyzing data secured over a long period of time concerning radio influence, corona loss, insulator leakage, and surge currents. Information secured from these recordings and analysis will be important to the transmission engineer in designing the most economical high-quality EHV dc transmission line.
Sparsity-certifying Graph Decompositions

We describe a new algorithm, the (k, l)-pebble game with colors, and use it to obtain a characterization of the family of (k, l)-sparse graphs and algorithmic solutions to a family of problems concerning tree decompositions of graphs. Special instances of sparse graphs appear in rigidity theory and have received increased attention in recent years. In particular, our colored pebbles generalize and strengthen the previous results of Lee and Streinu [12] and give a new proof of the Tutte-Nash-Williams characterization of arboricity. We also present a new decomposition that certifies sparsity based on the (k, l)-pebble game with colors. Our work also exposes connections between pebble game algorithms and previous sparse graph algorithms by Gabow [5], Gabow and Westermann [6] and Hendrickson [9].
Radar Detection of Iapetus

Saturn's satellite Iapetus has the largest albedo asymmetry of any natural satellite, with the optical albedo of its trailing hemisphere as much as 10 times that of its leading hemisphere ([ 1 ][1]). The sharp contrast on this synchronously rotating satellite suggests that exogenic materials, such