cssi/SciSciGPT-SciSciNet huggingface dataset:
Specification and implementations of interactive information systems

User Software Engineering is a methodology supported by automated tools for the development of interactive information systems. The specification process decomposes the system into user-program dialogue, database definition, and formal and informal description of system operations. Evolution of the specification is supported by tools for rapid construction of prototype versions of the system, and the resulting specification is easily transformed into the programming language PLAIN. This paper gives an overview of the USE development process, illustrating it with a development dictionary example.
Click Chemistry and ATRP: A Beneficial Union for the Preparation of Functional Materials

Since the concept of highly efficient and selective “click” reactions was put forth by Sharpless and coworkers, this branch of chemical transformations has been subject to an astounding degree of applications. Although click chemistry encompasses a wide variety of reactions, the CuI-catalyzed azide–alkyne cycloaddition has received the most attention. It has been increasingly employed in polymer functionalization and materials synthesis, especially in conjunction with controlled radical polymerization methods, such as Atom Transfer Radical Polymerization (ATRP). The CuI-catalyzed azide–alkyne cycloaddition is utilized particularly well with ATRP, due to the ease of incorporating clickable functionality into polymers prepared by ATRP and the use of the same catalyst in each process. This minireview summarizes and analyzes recent developments in the field of CuI-click chemistry as applied to ATRP, and how the combination of these two powerful techniques has greatly expanded the range of available materials and has contributed to fundamental understanding of this process.
Catalytic Decarboxylative sp−sp3 Coupling

A palladium-catalyzed 1,4-enyne synthesis was developed based the decarboxylative coupling of acetylides with allyl electrophiles. Stereochemical studies have implicated palladium−allyl−acetylides as intermediates. Thus, decarboxylative metalation was established as an environmentally benign alternative to transmetalation from alkynyl tin reagents.
A new synthesis of (±)-mesembrine involving the intramolecular nucleophilic attack of an allyl anion on a carbonyl function of an imide

Abstract A synthesis of (±)-mesembrine by the fluoride ion induced intramolecular cyclization of a suitably substituted allylsilane on to a neighbouring carbonyl function of an imide is described.
On the Relation between Nominal Devaluation and Real Devaluation: Evidence from African Countries

A country devalues its currency with an expectation that it will gain international competitiveness and increase its exports. However, the inflationary effects of devaluation could curtail its favourable effects unless nominal devaluation leads to real devaluation. In this paper, we consider the experiences of 21 African countries. After constructing the real and nominal effective exchange rates over the 1971I--2004III period, we employ the bounds-testing approach to cointegration and show that in almost all countries nominal devaluation leads to real devaluation in the short run. However, the shortdrun effects last into the long run only in three countries. Copyright 2007, Oxford University Press.
Hydrolysis of a Model for the 5'-Cap of mRNA by Dinuclear Copper(II) and Zinc(II) Complexes. Rapid Hydrolysis by Four Copper(II) Ions.

Two bis(triazacyclononane) ligands, 1,3-bis(1,4,7-triaza-1-cyclononyl)-p-xylene (pXTD) and 1,3-bis(1,4,7-triaza-1-cyclononyl)-m-xylene (mXTD), form stable dinuclear Cu(II) complexes (Cu2L). At pH 7.3, the predominant species are bis(hydroxide) complexes (Cu2L(OH)22+) as determined by equilibrium modeling of pH−potentiometric measurements. Several dinuclear and mononuclear Cu(II) complexes and a dinuclear Zn(II) complex promote the hydrolysis of GpppG, a model for the 5‘-cap of mRNA. At 0.125 mM complex, both Cu2(pXTD) and Cu2(mXTD) promote hydrolysis of GpppG approximately 100-fold more rapidly than does the monomeric Cu(TACN) complex (0.250 mM) at pH 7.3 and 37 °C (TACN = 1,4,7-triazacyclononane). The dependence of the rate constant on dinuclear Cu(II) complex concentration suggests that Cu2(pXTD) promotes hydrolysis through both a 1:1 complex (Cu2L−GpppG) and a 2:1 complex ((Cu2L)2−GpppG). The 2:1 complex is 20-fold more reactive than the 1:1 complex; a first-order rate constant of 1.1 × 10-4 s-1 is det...
Optical satellite networks

With high-speed space optical crosslinks, an optical satellite network as part of a larger integrated space-terrestrial network is now feasible. This radical technology building block can have profound transforming effects on space system architectures.
S-curve dynamics of trade between Sweden and her trading partners

Abstract The S-curve sums up the dynamic relationship between terms of trade and trade balance. This pattern has received weak support in some developed and less developed countries when aggregate trade data are used. Empirical regularities based on aggregate trade data can be biased since aggregation can potentially suppress some of the patterns observed in trade at the bilateral level. This paper overcomes this problem by employing bilateral trade data from Sweden and finds that the S-curve is invariant to this level of disaggregation. Indeed, Sweden has a bilateral S-curve with 12 out of 17 cases examined for the 1980Q1–2005Q1 period.
Interface phenomena at semiconductor heterojunctions: Local-density valence-band offset in GaAs/AlAs

The valence-band offset ΔE v at the lattice-matched GaAs/AlAs(001) interface is derived from highly precise self-consistent all-electron local-density band-structure calculations of the (GaAs) n (AlAs) n (001) superlattices (with n ≤ 3). We calculate ΔE v , by using the core levels — available uniquely from an all-electron approach—as reference energies. Since these are experimentally accessible quantities, a direct comparison with experiment is, in principle, possible. We find that ΔE v = 0.5 ± 0.05 eV, in very good agreement with recent experimental results (ΔE v = 0.45−0.55 eV). Calculated core-level shifts are also compared to experiment. These results, which are closely related to changes in the charge-density distribution at the interface, contribute to understanding the underlying mechanism of the band discontinuity.
Gamma-ray Burst Flares: X-ray Flaring. II

We present a catalog of 498 flaring periods found in gamma-ray burst (GRB) light curves taken from the online Swift X-Ray Telescope GRB Catalogue. We analyzed 680 individual light curves using a flare detection method developed and used on our UV/optical GRB Flare Catalog. This method makes use of the Bayesian Information Criterion to analyze the residuals of fitted GRB light curves and statistically determines the optimal fit to the light curve residuals in an attempt to identify any additional features. These features, which we classify as flares, are identified by iteratively adding additional 'breaks' to the light curve. We find evidence of flaring in 326 of the analyzed light curves. For those light curves with flares, we find an average number of ∼1.5 flares per GRB. As with the UV/optical, flaring in our sample is generally confined to the first 1000 s of the afterglow, but can be detected to beyond 10{sup 5} s. Only ∼50% of the detected flares follow the 'classical' definition of Δt/t ≤ 0.5, with many of the largest flares exceeding this value.
Free convective motion in an infinite vertical porous slot: the non-Darcian regime

Analyse numerique de la convection naturelle dans un milieu poreux sature limite par 2 plaques paralleles verticales rapprochees, dans le cas ou l'ecoulement n'obeit pas a la loi de Darcy
Efficient determination of the critical parameters and the statistical quantities for Klein–Gordon and sine-Gordon equations with a singular potential using generalized polynomial chaos methods

Abstract We consider the Klein–Gordon and sine-Gordon type equations with a point-like potential, which describe the wave phenomenon with a defect. The singular potential term yields a critical phenomenon – that is, the solution behavior around the critical parameter value bifurcates into two extreme cases. Finding such critical parameter value and the associated statistical quantities demands a large number of individual simulations with different parameter values. Pinpointing the critical value with arbitrary accuracy is even more challenging. In this work, we adopt the generalized polynomial chaos (gPC) method to determine the critical values and the mean solutions around such values. First, we consider the critical value associated with the strength of the singular potential for the Klein–Gordon equation. We expand the solution in the random variable associated with the parameter. The obtained equations are solved using the Chebyshev collocation method. Due to the existence of the singularity, the Gibbs phenomenon appears in the solution, yielding a slow convergence of the numerically computed critical value. To deal with the singularity, we adopt the consistent spectral collocation method. The gPC method, along with the consistent Chebyshev method, determines the critical value and the mean solution highly efficiently. We then consider the sine-Gordon equation, for which the critical value is associated with the initial velocity of the kink soliton solution. The critical behavior in this case is that the solution passes through (particle-pass), is trapped by (particle-capture), or reflected by (particle-reflection) the singular potential if the initial velocity of the soliton solution is greater than, equal to, or less than the critical value, respectively. Due to the nonlinearity of the equation, we use the gPC mean value instead of reconstructing the solution to find the critical parameter. Numerical results show that the critical value can be determined efficiently and accurately by the proposed method.
On the Nondegeneracy of Constant Mean Curvature Surfaces

We prove that many complete, noncompact, constant mean curvature (CMC) surfaces $$f:\Sigma \to \mathbb{R}^3$$ are nondegenerate; that is, the Jacobi operator Δ f + | A f |2 has no L2 kernel. In fact, if ∑ has genus zero with k ends, and if f (∑) is embedded (or Alexandrov immersed) in a half-space, then we find an explicit upper bound for the dimension of the L2 kernel in terms of the number of non-cylindrical ends. Our main tool is a conjugation operation on Jacobi fields which linearizes the conjugate cousin construction. Consequences include partial regularity for CMC moduli space, a larger class of CMC surfaces to use in gluing constructions, and a surprising characterization of CMC surfaces via spinning spheres.
Solving parametric problems on trees

Abstract We consider optimization problems on weighted trees, including weighted versions of the minimum vertex cover and the minimum dominating set problems, where vertex and edge weights vary as linear functions of time. For each of the problems studied here, we derive bounds on the number of breakpoints of the piecewise linear functions describing the cost of the optimum solution and we present efficient methods for constructing these functions. We also consider the problem of determining optimum steady-state solutions and finding the time t∞ at which the steady state is reached.
Visualization of molecular interactions using bimolecular fluorescence complementation analysis: Characteristics of protein fragment complementation

Investigations of the molecular processes that sustain life must include studies of these processes in their normal cellular environment. The bimolecular fluorescence complementation (BiFC) assay provides an approach for the visualization of protein interactions and modifications in living cells. This assay is based on the facilitated association of complementary fragments of a fluorescent protein that are fused to interaction partners. Complex formation by the interaction partners tethers the fluorescent protein fragments in proximity to each other, which can facilitate their association. The BiFC assay enables sensitive visualization of protein complexes with high spatial resolution. The temporal resolution of BiFC analysis is limited by the time required for fluorophore formation, as well as the stabilization of complexes by association of the fluorescent protein fragments. Many modifications and enhancements to the BiFC assay have been developed. The multicolor BiFC assay enables simultaneous visualization of multiple protein complexes in the same cell, and can be used to investigate competition among mutually exclusive interaction partners for complex formation in cells. The ubiquitin-mediated fluorescence complementation (UbFC) assay enables visualization of covalent ubiquitin family peptide conjugation to substrate proteins in cells. The BiFC assay can also be used to visualize protein binding to specific chromatin domains, as well as other molecular scaffolds in cells. BiFC analysis therefore provides a powerful approach for the visualization of a variety of processes that affect molecular proximity in living cells. The visualization of macromolecular interactions and modifications is of great importance owing to the central roles of proteins, nucleic acids and other macromolecular complexes in the regulation of cellular functions. This tutorial review describes the BiFC assay, and discusses the advantages and disadvantages of this experimental approach. The review will be of interest to scientists interested in the investigation of macromolecular interactions or modifications who need exquisite sensitivity for the detection of their complexes or conjugates of interest.
Preparation of allylic alcohols by alkene transfer from zirconium to zinc

Abstract Transmetalation of alkenyl zirconocenes 2 to the corresponding organozinc compounds 3 occurs rapidly and at low temperature in the presence of stoichiometric amounts of commercially available dimethyl- or diethylzinc. Subsequent addition of aldehydes provides an in situ protocol for the conversion of alkynes 1 into allylic alcohols 5 in good to excellent yields.
Dependence of the Josephson coupling of unconventional superconductors on the properties of the tunneling barrier.

The Josephson coupling between a conventional and an unconventional superconductor is investigated as a function of the properties of the tunneling barrier. A simple model is adopted for the tunneling probability and it is shown that its variation dramatically affects the [ital I][sub [ital c]][ital R][sub [ital n]] product of an [ital s]-[ital d], as opposed to an [ital s]-[ital s] junction. Based on these conclusions, experiments are proposed to probe the symmetry of the order parameter in high-temperature superconductors.
Novel topoisomerase I-targeting antitumor agents synthesized from the N,N,N-trimethylammonium derivative of ARC-111, 5H-2,3-dimethoxy-8,9-methylenedioxy-5-[(2-N,N,N-trimethylammonium)ethyl]dibenzo[c,h][1,6]-naphthyridin-6-one iodide

Several new TOP1-targeting agents were prepared using as an intermediate the N,N,N-trimethyl quaternary ammonium salt 2 of ARC-111. Direct displacement of the quaternary ammonium group with hydroxide, cyclopropylamine, imidazole, 1H-1,2,3-triazole, alkylethylenediamines, ethanolamine, and polyhydroxylated alkylamines provides a convenient means for furthering insight into the structure–activity relationships within this series of non-camptothecin TOP1-targeting agents. The relative TOP1-targeting activities and cytotoxicities were evaluated in RPMI8402 and P388 cells and their camptothecin-resistant variants. Their potential to serve as substrates for the efflux transporters MDR1 and BCRP, which are associated with multidrug resistance, was also assessed.
Matrix models for supersymmetric Chern-Simons theories with an ADE classification

We consider $ \mathcal{N} $ = 3 supersymmetric Chern-Simons (CS) theories that contain product U(N ) gauge groups and bifundamental matter fields. Using the matrix model of Kapustin, Willett and Yaakov, we examine the Euclidean partition function of these theories on an S 3 in the large N limit. We show that the only such CS theories for which the long range forces between the eigenvalues cancel have quivers which are in one-to-one correspondence with the simply laced affine Dynkin diagrams. As the A n series was studied in detail before, in this paper we compute the partition function for the D 4 quiver. The D 4 example gives further evidence for a conjecture that the saddle point eigenvalue distribution is determined by the distribution of gauge invariant chiral operators. We also see that the partition function is invariant under a generalized Seiberg duality for CS theories.
Iridium catalyzed reversible dehydrogenation – Hydrogenation of quinoline derivatives under mild conditions

Abstract The potential of a hydrogen-based energy economy is limited by the fact that hydrogen gas is difficult to store and transport. Storing hydrogen in the form of liquid organic hydrogen-carriers (LOHCs) is a highly attractive alternative to current options but it requires the development of catalytic means of reversibly hydrogenating and dehydrogenating these carriers under mild conditions and ideally using a single catalyst for both processes. We report the optimization of two families of previously reported hydrogenation catalysts for the reverse reaction, dehydrogenation of N-heterocyclic substrates. These complexes are capable of catalyzing both dehydrogenation and hydrogenation reactions in alternation, giving high yields in both directions. Importantly, our complexes do not require high temperatures, high pressures of H 2 or strong base for the hydrogenation step.
Dosimetric evaluation of lead and tungsten eye shields in electron beam treatment

Abstract Purpose : The purpose of this study is to report that commercially available eye shields (designed for orthovoltage x-rays) are inadequate to protect the ocular structures from penetrating electrons for electron beam energies equal to or greater than 6 MeV. Therefore, a prototype medium size tungsten eye shield was designed and fabricated. The advantages of the tungsten eye shield over lead are discussed. Methods and Materials : Electron beams (6–9 MeV) are often used to irradiate eyelid tumors to curative doses. Eye shields can be placed under the eyelids to protect the globe. Film and thermoluminescent dosimeters (TLDs) were used within a specially constructed polystyrene eye phantom to determine the effectiveness of various commercially available internal eye shields (designed for orthovoltage x-rays). The same procedures were used to evaluate a prototype medium size tungsten eye shield (2.8 mm thick), which was designed and fabricated for protection of the globe from penetrating electrons for electron beam energy equal to 9 MeV. A mini-TLD was used to measure the dose enhancement due to electrons backscattered off the tungsten eye shield, both with or without a dental acrylic coating that is required to reduce discomfort, permit sterilization of the shield, and reduce the dose contribution from backscattered electrons. Results : Transmission of a 6 MeV electron beam through a 1.7 mm thick lead eye shield was found to be 50% on the surface (cornea) of the phantom and 27% at a depth of 6 mm (lens). The thickness of lead required to stop 6–9 MeV electron beams is impractical. In place of lead, a prototype medium size tungsten eye shield was made. For 6 to 9 MeV electrons, the doses measured on the surface (cornea) and at 6 mm (lens) and 21 mm (retina) depths were all less than 5 % of the maximum dose of the open field (4 × 4 cm). Electrons backscattered off a tungsten eye shield without acrylic coating increased the lid dose from 85 to 123 % at 6 MeV and 87 to 119 % at 9 MeV. For the tungsten eye shield coated with 2∼3 m of dental acrylic, the lid dose was increased from 85 to 98.5% at 6 MeV and 86 to 106% at 9 MeV. Conclusion : Commercially available eye shields were evaluated and found to be clearly inadequate to protect the ocular structures for electron beam energies equal to or greater than 6 MeV. A tungsten eye shield has been found to provide adequate protection for electrons up to 9 MeV. The increase in lid dose due to electrons backscattered off the tungsten eye shield should be considered in the dose prescription. A minimum thickness of 2 mm dental acrylic on the beam entrance surface of the tungsten eye shield was found to reduce the backscattered electron effect to acceptable levels.
Variational Splines and Paley–Wiener Spaces on Combinatorial Graphs

Notions of interpolating variational splines and Paley–Wiener spaces are introduced on a combinatorial graph G. Both of these definitions explore existence of a combinatorial Laplace operator on G. The existence and uniqueness of interpolating variational splines on a graph is shown. As an application of variational splines, the paper presents a reconstruction algorithm of Paley–Wiener functions on graphs from their uniqueness sets.
RADIALLY EXTENDED, STRATIFIED, LOCAL MODELS OF ISOTHERMAL DISKS

We consider local, stratified, numerical models of isothermal accretion disks. The novel feature of our treatment is that radial extent Lx and azimuthal extent Ly satisfy H Lx , Ly R, where H is the scale height and R is the local radius. This enables us to probe mesoscale structure in stratified thin disks. We evolve the model at several resolutions, sizes, and initial magnetic field strengths. Consistent with earlier work, we find that the saturated, turbulent state consists of a weakly magnetized disk midplane coupled to a strongly magnetized corona, with a transition at |z| ~ 2H. The saturated α 0.01-0.02. A two-point correlation function analysis reveals that the central 4H of the disk is dominated by small-scale turbulence that is statistically similar to unstratified disk models, while the coronal magnetic fields are correlated on scales ~10H. Nevertheless angular momentum transport through the corona is small. A study of magnetic field loops in the corona reveals few open field lines and predominantly toroidal loops with a characteristic distance between footpoints that is ~H. Finally, we find quasi-periodic oscillations with characteristic timescale ~30 Ω–1 in the magnetic field energy density. These oscillations are correlated with oscillations in the mean azimuthal field; we present a phenomenological, alpha-dynamo model that captures most aspects of the oscillations.
Slope lengths and generalized augmented links

In this paper, we determine geometric information on slope lengths of a large class of knots in the 3–sphere, based only on diagrammatical properties of the knots. In particular, we show such knots have meridian length strictly less than 4, and we find infinitely many families with meridian length approaching 4 from below. Finally, we present an example to show that, in contrast to the case of the regular augmented link, longitude lengths of these knots cannot be determined by a function of the number of twist regions alone.
Design, synthesis and biological evaluation of 7-azatricyclodecanes : Analogues of cocaine

The synthesis and biological activity of a series of azatricyclodecane analogues of cocaine are described. All compounds studied in this series exhibit nanomolar potency and good selectivity for the serotonin transporter versus the dopamine transporter.
ON FOUR-DIMENSIONAL COMPACTIFICATIONS OF F-THEORY

Abstract Branches of moduli space of F-theory in four dimensions are investigated. The transition between two branches is described as a 3-brane-instanton transition on a 7-brane. A dual heterotic picture of the transition is presented and the F-theory-heterotic theory map is given. The F-theory data, complex structure of the Calabi-Yau fourfold and the instanton bundle on the 7-brane is mapped to the heterotic bundle on the elliptic Calabi-Yau threefold CY3. The full moduli space has a web structure which is also found in the moduli space of semi-stable bundles on CY3. Matter content of the four-dimensional theory is discussed in both F-theory and heterotic theory descriptions.
R-axion detection at LHC

Supersymmetric models with spontaneously broken approximate R-symmetry contain a light spin 0 particle, the R-axion. The properties of the particle can be a powerful probe of the structure of the new physics. In this paper, we discuss the possibilities of the R-axion detection at the LHC experiments. It is challenge to observe this light particle in the LHC environment. However, for typical values in which the mass of the R-axion is a few hundred MeV, we show that those particles can be detected by searching for displaced vertices from R-axion decay.
Second-order torque components in the Schrage motor operating at synchronous speed

The operation of a Schrage motor at synchronous speed is considered, and on the assumption that the air-gap flux at this speed contains space harmonics, an expression for the torque in terms of flux-axis position is derived. This shows that the torque consists of the main component, which is constant for constant brush separation, and variable components depending on (a) unbalance in the secondary circuits owing to errors in brush-separation angles and/or unequal secondary resistances, and (b) the assumed space harmonics of flux. The variable torque components give rise to superimposed speed oscillations and primary-current hunting, when the average speed is just above or below synchronism. An experimental method of investigating the torque is then given, together with two methods of measuring the harmonic content of the air-gap flux. The latter measurements are used to predict the amount by which the total torque varies with the air-gap flux-axis position at synchronous speed. Possible errors are discussed, and an approximate correction for non-linearity due to the brush-contact effect is derived and applied. Experimental results given for a 2-phase machine show reasonable agreement with the theory.
Area-dependence of spin-triplet supercurrent in ferromagnetic Josephson junctions

Josephson junctions containing multiple ferromagnetic layers can carry spin-triplet supercurrent under certain conditions. Large-area junctions containing multiple domains are expected to have a random distribution of 0 or $\ensuremath{\pi}$ coupling across the junction surface, whereas magnetized samples should have uniquely $\ensuremath{\pi}$ coupling everywhere. We have measured the area-dependence of the critical current in such junctions, and confirm that the critical current scales linearly with area in magnetized junctions. For as-grown (multidomain) samples, the results are mixed. Samples grown on a thick Nb base exhibit critical currents that scale sublinearly with area, while samples grown on a smoother Nb/Al multilayer base exhibit critical currents that scale linearly with area. The latter results are consistent with a theoretical picture due to Zyuzin and Spivak that predicts that the as-grown samples should have global $\ensuremath{\pi}/2$ coupling.
Exponent bounds for a convolution inequality in Euclidean space with applications to the Navier-Stokes equations

This is the publisher’s final pdf. The published article is copyrighted by the American Mathematical Society and can be found at: http://www.ams.org/publications/journals/journalsframework/proc.
A superprocess involving both branching and coalescing

We consider a superprocess with coalescing Brownian spatial motion. We first point out a dual relationship between two systems of coalescing Brownian motions. In consequence we can express the Laplace functionals for the superprocess in terms of coalescing Brownian motions, which allows us to obtain some explicit results. We also point out several connections between such a superprocess and the Arratia flow. A more general model is discussed at the end of this paper.
Long term aging of selenide glasses: evidence of sub-Tg endotherms and pre-Tg exotherms.

Long term aging, extending from months to several years, is studied on several families of chalcogenide glasses including the Ge–Se, As–Se, and Ge–As–Se systems. Special attention is given to the As–Se binary, a system that displays a rich variety of aging behavior intimately tied to sample synthesis conditions and the ambient environment in which samples are aged. Calorimetric (modulated DSC) and Raman scattering experiments are undertaken. Our results show all samples display a sub-Tg endotherm typically 10–70 °C below Tg in glassy networks possessing a mean coordination number r in the 2.25 < r < 2.45 range. Two sets of AsxSe100−x samples aged for eight years were compared, set A consisted of slow cooled samples aged in the dark, and set B consisted of melt-quenched samples aged at laboratory environment. Samples of set B in the As concentration range, 35% < x < 60%, display a pre-Tg exotherm, but the feature is not observed in samples of set A. The aging behavior of set A presumably represents intrinsic aging in these glasses, while that of set B is extrinsic due to the presence of light. The reversibility window persists in both sets of samples, but is less well defined in set B. These findings contrast with a recent study by Golovchak et al (2008 Phys. Rev. B 78 014202), which finds the onset of the reversibility window moved up to the stoichiometric composition (x = 40%). Here we show that the up-shifted window is better understood as resulting due to demixing of As4Se4 and As4Se3 molecules from the backbone, i.e., nanoscale phase separation (NSPS). We attribute sub-Tg endotherms to compaction of the flexible part of the networks upon long term aging, while the pre-Tg exotherm is to NSPS. The narrowing and sharpening of the reversibility window upon aging is interpreted as the slow 'self-organizing' stress relaxation of the phases just outside the intermediate phase, which itself is stress free and displays little aging.
Chloromethylaluminum 2 (2-propenyl)anilide - a convenient reagent for the conversion of lactones into protected hydroxy acids

Abstract The title reagent reacts with γ and δ lactones to provide hydroxy amides which can be easily converted into protected N-acyl indoles. Mild saponification provides indole and the protected hydroxy acid.
Tight-binding calculation of radiation loss in photonic crystal CROW

We utilize the tight binding approximation within a light cone picture to relate the quality factor of CROWs with that of isolated cavity and to design CROWs with low intrinsic loss across the entire band.
An application of Bayesian variable selection to spatial concurrent linear models

Spatial concurrent linear models, in which the model coefficients are spatial processes varying at a local level, are flexible and useful tools for analyzing spatial data. One approach places stationary Gaussian process priors on the spatial processes, but in applications the data may display strong nonstationary patterns. In this article, we propose a Bayesian variable selection approach based on wavelet tools to address this problem. The proposed approach does not involve any stationarity assumptions on the priors, and instead we impose a mixture prior directly on each wavelet coefficient. We introduce an option to control the priors such that high resolution coefficients are more likely to be zero. Computationally efficient MCMC procedures are provided to address posterior sampling, and uncertainty in the estimation is assessed through posterior means and standard deviations. Examples based on simulated data demonstrate the estimation accuracy and advantages of the proposed method. We also illustrate the performance of the proposed method for real data obtained through remote sensing.
Significant variability in the mode of ventricular tachycardia induction and its implications for interpretation of acute drug testing

Abstract Fifty-four patients with previous myocardial infarction and sustained ventricular tachycardia on fibrillation underwent two electrophysiologic studies in the drug-free state within 72 hours. Although the concordance of overall ventricular tachycardia induction over the 2 days was good (87% of patients), there was variability in the number of extrastimuii needed to induce sustained ventricular tachycardia on each day in 60% of patients. Of those in whom ventricular tachycardia was inducible on both days, 40% required additional extrastimuli and 20% required fewer extrastimuli. A change by two or more extrastimuli was found in 12% of patients. There was no correlation between the variability observed and multiple clinical and laboratory parameters (including the aggressiveness of the stimulation protocol); however, the direction of the variability (easier or harder to induce) correlated with changes in ventricular refractoriness. Inherent day-to-day variability may affect the reproducibility of electrophysiologic studies and influence the results of serial drug testing.
Pion form factor and quark mass evolution in a light-front quark model

Abstract We discuss the soft contribution to the elastic pion form factor with the mass evolution from current to constituent quark being taken into account in a light-front quark model(LFQM).
Watchman routes in the presence of a pair of convex polygons

Abstract Given a set of polygonal obstacles in the plane, the shortest watchman route problem asks for a closed route from which each point in the exterior of the polygons is visible to some point along the route. This problem is known to be NP-hard and the development of an efficient approximation algorithm is still open. We present an O(n2) time algorithm for computing the shortest watchman route for a pair of convex polygons, where n is the total number of edges in the polygons. We also show that the algorithm can be easily extended, without increasing its complexity, to compute the shortest watchman route when the polygons are enclosed by a third convex polygon.
A cost benefit analysis of a V2G-capable electric school bus compared to a traditional diesel school bus

Abstract Fuel expenses, diesel exhaust health externalities, and climate change are concerns that encourage the use of electric vehicles. Vehicle-to-grid (V2G) policies provide additional economic incentives. This analysis evaluates the costs and benefits associated with the use of electric vehicles and determines the cost effectiveness of using a V2G-capable electric school bus compared to a traditional diesel school bus. Several factors were analyzed, including fuel expense, electricity and battery costs, health externalities, and frequency regulation market price. The V2G-capable electric bus provides the school savings of $6070 per seat in net present value and becomes a net present benefit after five years of operation. Without externalities, the net present benefit would be $5700 per seat. If the entire school district’s fleet switched to V2G-capable electric buses, the net present savings would be upwards of $38 million. A sensitivity analysis was conducted to determine how the factors influenced the costs and benefits. In all cases, purchasing an electric school bus is consistently a net present benefit. Policies could be set into place to incentivize public school adoption of electric buses, encourage more efficient batteries, and develop V2G capabilities.
Full Spark Frames

Finite frame theory has a number of real-world applications. In applications like sparse signal processing, data transmission with robustness to erasures, and reconstruction without phase, there is a pressing need for deterministic constructions of frames with the following property: every size-M subcollection of the M-dimensional frame elements is a spanning set. Such frames are called full spark frames, and this paper provides new constructions using the discrete Fourier transform. Later, we prove that full spark Parseval frames are dense in the entire set of Parseval frames, meaning full spark frames are abundant, even if one imposes an additional tightness constraint. Finally, we prove that testing whether a given matrix is full spark is hard for NP under randomized polynomial-time reductions, indicating that deterministic full spark constructions are particularly significant because they guarantee a property which is otherwise difficult to check.
Effects of Heavy Ions on Microcircuits in Space: Recently Investigated Upset Mechanisms

Upsets of microcircuits in space have been attributed to heavy ions. In recent studies of the failure mechanisms, we have employed a wide range of test methods. These studies and the application of the test results to space borne microcircuits are presented.
Photochemical Control of DNA Structure through Radical Disproportionation

Photolysis of an aryl sulfide-containing 5,6-dihydropyrimidine (1) at 350 nm produces high yields of thymidine and products resulting from trapping of a 5,6-dihydrothymidin-5-yl radical by O₂ or thiols. Thymidine is believed to result from disproportionation of the radical pair originally generated from C--S bond homolysis of 1 on the microsecond timescale, which is significantly shorter than other photochemical transformations of modified nucleotides into their native forms. Duplex DNA containing 1 is destabilized, presumably due to disruption of π-stacking. Incorporation of 1 within the binding site of the restriction endonuclease EcoRV provides a photochemical switch for turning on the enzyme's activity. In contrast, 1 is a substrate for endonuclease VIII and serves as a photochemical off switch for this base excision repair enzyme. Modification 1 also modulates the activity of the 10-23 DNAzyme, despite its incorporation into a nonduplex region. Overall, dihydropyrimidine 1 shows promise as a tool to provide spatiotemporal control over DNA structure on the miscrosecond timescale.
Charge Transport Dilemma of Solution-Processed Nanomaterials

A large variety of nanoparticles were synthesized during the last 25 years and are used now as “building blocks” for a variety of materials. Bottom-up solution processing of devices emerged as a promising direction of their technological applications because this method can (a) utilize intrinsic ability of nanocolloids to self-organize, (b) reduce high energy and equipment cost of device manufacturing, and (c) impart new functionalities to electronic devices. However the technological impact of solution processable semiconductor materials—although potentially considerable—has been so far limited because of the long-standing dilemma between the need for effective colloidal stabilization of nanoparticles and effective charge transport. Surfactants and other organic materials being used to synthesize and/or disperse nanocolloids introduce a barrier for charge transport between the particles. Although these barriers do make it impossible to use them in electronic devices, they certainly make it more difficult...
Acute Testicular Ischemia Results in Germ Cell-Specific Apoptosis in the Rat

Testis torsion-induced aspermatogenesis is not necessarily due to permanent loss of blood flow nor to dysfunctional Leydig cells or Sertoli cells. This investigation was undertaken to gain further insight into the mechanism underlying torsion-induced germ cell loss. Male rats were subjected to 1-h or 2-h ischemiainducing torsion, and testes were examined at either 1, 2, 4, 24, or 48 h after torsion, depending on the study. Testes were examined for evidence of 1) in situ apoptosis by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick-end labeling (TUNEL) technique, 2) apoptosis by the DNA "laddering" technique, 3) leukocyte margination and diapedesis in testicular vessels by immunocytochemical and histological techniques, and 4) testicular lipid peroxidation by the thiobarbituric acid reactive substances assay. The first TUNEL evidence for torsion-induced apoptosis was at 4 h after repair of 1-h torsion. Induction of apoptosis was confirmed by the electrophoretic laddering of DNA fragments. It was hypothesized that apoptosis was induced by reactive oxygen species arising from reperfusing leukocytes. A significant increase in both leukocyte margination and diapedesis occurred 4 h after torsion repair as did a significant increase in intratesticular lipid peroxidation products. These events were contemporaneous with the first appearance of apoptosis and consistent with the hypothesis that post-torsion, germ cell-specific apoptosis is induced by reactive oxygen species.
Asymmetric synthesis of unusual amino acids : An enantioselective synthesis of the four isomers of D- and L-O-Methyl-2′, β-Dimethyltyrosine

Abstract The four individual isomers of D- and L-O-methyl-2′, β-dimethyltyrosines have been synthesized in high optical purity. The evidence for asymmetric induction was cofirmed by the X-ray analysis of one of the key intermediates.
Attention, physics and teaching

A specific physics problem format has been successful in helping students to develop attentional strategies in solving standard physics problems. The basic structure of this format simultaneously presents alternative patterns of possible solutions/approaches with a correlated package of several related facts/criteria that can be utilized as a foundation to construct a formal analysis of the problem.
Degrees and Dimensions of Social Interaction in Tribal Groupings: A Sociometric Study

Abstract On a administre un inventaire de quinze questions sociometriques a onze groupes d'eleves d'ecoles primaires et secondaires, d'une ecole d'instituteurs, et d'une ecole pour jeunes mineurs de la region miniere (Copperbelt) de Zambie (N = 274). Les choix ont ete analyses en prenant l'origine tribale comme base de classification pour les groupements dans les classes et pour tous les repondants. L'origine tribale represente une categorie importante pour l'interaction sociale a l'interieur des groupes institutionnels quand la distance est grande. Les dimensions de l'inventaire, que fait appara[icaron]tre une analyse factorielle basee sur les groupements par tribu des repondants, suivent trois axes et pourraient correspondre a l'autorite (leadership) dans un systeme institutionnel, l'acceptation par les pairs et l'origine ethnique. L'A. discute de ces resultats en se referant a d'autres recherches sur la distance sociale et montre queues modifications de la theorie traditionnelle ils suggerent.
Public Investment in Resource-Abundant Developing Countries

Natural resource revenues provide a valuable source to finance public investment in developing countries, which frequently face borrowing constraints and tax mobilization problems. This paper develops a dynamic stochastic model to analyze the macroeconomic effects of investing resource revenues, making explicit the role of public investment inefficiency, absorptive capacity constraints, Dutch disease, and financing needs to sustain capital. Revenue exhaustibility raises medium-term issues of how to sustain capital built during a windfall, while revenue volatility raises short-term concerns about macroeconomic instability. Using the model, country applications show how combining public investment with a resource fund—a sustainable investing approach—can address the problems associated with exhaustibility and volatility. The applications also demonstrate how the model can be used to determine the appropriate magnitude of the investment scaling-up (accounting for the financing needs to sustain capital) and the adequate size of a stabilization fund (buffer).
Amplitudes of 3D and 6D maximal superconformal theories in supertwistor space

We use supertwistor space to construct scattering amplitudes of maximal superconformal theories in three and six dimensions. In both cases, the constraints of superconformal invariance and rationality imply that the three-point amplitude vanishes on-shell, which constrains the four-point amplitude to have vanishing residues in all channels. In three dimensions, we nd a unique solution for the four-point amplitude and demonstrate that it agrees with the component result in the BLG theory. This suggests that BLG is the unique three-dimensional theory with classical OSp(8|4) symmetry that admits a Lagrangian description. We also show that one can derive the four-point amplitude of the ABJM theory from our N = 8 result by reducing the supersymmetry, which implies that the tree-level Yangian symmetry recently found in ABJM is also present in BLG. In six dimensions, we find that the consistency conditions imply that all tree-level amplitudes vanish. This leads us to conjecture that an interacting six-dimensional theory with classical OSp(8|4) symmetry does not have a Lagrangian description, local or nonlocal, unless the (2, 0) tensor multiplets are supplemented by additional degrees of freedom.
Relaxation of Thermal Stress in Phase‐Separated Borosilicate Glasses

Although the “apparent” viscosity of borosilicate glasses is known to increase with the progress of phase separation, temperatures at which the thermal strain is relieved are seen to decrease by the increase of phase separation. This behavior is explained by the difference in the “real” viscosity of each phase in the phase-separated glass and by the very low thermal expansion of the higher viscosity SiO2-rich phase. The “annealing point” based on ASTM designations loses its meaning for phase-separated glasses of this type.
On the Eccentricity Distribution of Coalescing Black Hole Binaries Driven by the Kozai Mechanism in Globular Clusters

In a globular cluster, hierarchical triple black hole systems can be produced through binary-binary interaction. It has been proposed recently that the Kozai mechanism could drive the inner binary of the triple system to merge before it is interrupted by interactions with other field stars. We investigate qualitatively and numerically the evolution of the eccentricities in these binaries under gravitational radiation (GR) reaction. We predict that ~30% of the systems will possess eccentricities greater than 0.1 when their emitted gravitational waves pass through 10 Hz frequency. The implications for gravitational wave detection, especially the relevance to data analyses for broadband laser interferometer gravitational wave detectors, are discussed.
Enhancing the scope of the Diels-Alder reaction through isonitrile chemistry: emergence of a new class of acyl-activated dienophiles.

α,β-Unsaturated imides, formylated at the nitrogen atom, comprise a new and valuable family of dienophiles for servicing Diels–Alder reactions. These systems are assembled through extension of recently discovered isonitrile chemistry to the domain of α,β-unsaturated acids. Cycloadditions are facilitated by Et2AlCl, presumably via chelation between the two carbonyl groups of the N-formyl amide. Applications of the isonitrile/Diels–Alder logic to the IMDA reaction, as well as methodologies to modify the N-formyl amide of the resultant cycloaddition product, are described. It is expected that this easily executed chemistry will provide a significant enhancement for application of Diels–Alder reactions to many synthetic targets.
Electronic polarization at surfaces and thin films of organic molecular crystals: PTCDA

Abstract The electronic polarization energies, P = P + + P − , of a perylenetetracarboxylic acid dianhydride (PTCDA) cation and anion in a crystalline thin film on a metallic substrate are computed and compared with measurements of the PTCDA transport gap on gold and silver. Both experiments and theory show that P is 500 meV larger in a PTCDA monolayer than in 50 A films. Electronic polarization in systems with surfaces and interfaces are obtained self-consistently in terms of charge redistribution within molecules.
Upper limits on the X-ray emission of "uranium" stars

A paper by Qian & Wasserburg suggests the optical absorption lines of uranium observed in the spectra of ultra–metal-poor stars (defined as [Fe/H] < -3) arise from contamination from a supernova in a binary star system. Assuming the binary survived the explosion, a collapsed compact object may be present and implies potential accretion processes with accompanying X-ray emission. Upper limits on X-ray emission from an accreting compact object are described here.