cssi/SciSciGPT-SciSciNet huggingface dataset:
Experimental Analysis of the Turbulent Shear Stresses for Distorted Supersonic Boundary Layers

An experimental analysis of the turbulent shear stresses for a supersonic boundary layer distorted by streamline curvature-induced pressure gradients was performed using laser Doppler velocimetry. Four pressure-gradient  ows were examined: a nominally zero-pressure-gradient case (M = 2.8, Reu = 1.1 3 10, b = 0.02); a favorable-pressure gradient (M = 2.9, Reu = 1.5 3 10, b = 20.5); an adverse-pressure gradient (M = 2.7, Reu = 1.2 3 10, b = 0.9); and a successive-pressure gradient (M = 2.5, Reu = 1.2 3 10, b = 21.0, following a region of b = 0.9). For the favorable-pressure gradient, the turbulent shearstress levels across the boundary layer decreased by 70 – 100%, as compared to the zero-pressure-gradient boundary layer. For the adverse-pressure gradient, a 70 – 100% increase was observed. For the combinedpressure gradient, the shear stresses returned to values similar to the zero-pressure-gradient  ow. A new pressure gradient parameter was found to correlate well with the peak shear-stress ampli cation. It was also postulated that the shear-stress ampli cations were in part the result of the nonuniform bulk dilatation/compression and streamline divergence/convergence, implying a forcing phenomena that in uenced the statistical correlation. The combined-pressure-gradient  ow demonstrated that the turu9v9 bulent structure adjusts relatively rapidly to the distortion. Numerical simulations of the mean velocity obtained with a k-v turbulence model were found to agree very well with the present data. With the exception of the zero-pressure-gradient  ow, the magnitudes of the turbulent shear stresses were not accurately reproduced; however, correct trends were predicted.
Silica nanoparticles as a reusable catalyst: a straightforward route for the synthesis of thioethers, thioesters, vinyl thioethers and thio-Michael adducts under neutral reaction conditions

A simple and straightforward route for the synthesis of thioethers, thioesters, vinyl thioethers and thio-Michael adducts has been demonstrated using silica nanoparticles (NPs) as a reusable catalyst via the 1,2-addition of thiols to alkenes, alkynes and alkyl/acyl halides, and the 1,4-addition of thiols to conjugated alkenes at room temperature.
Effects of Solution Composition and pH on the Reductive Dechlorination of Hexachloroethane by Iron Sulfide

Transition metal sulfide minerals are under investigation as potentially important abiotic reductants for chlorinated organic pollutants in anaerobic environments. This paper describes parametric rate studies done to evaluate the influence of environmental variables such as pH and ionic and organic solution composition on the reductive dechlorination of hexachloroethane (HCA) by FeS (poorly crystalline mackinawite). Results indicate that the reaction takes place at the mineral surface and is strongly pH-dependent. The influence of pH was explained by an acid/base equilibrium between two FeS surface species with different reactivities. Tetrachloroethylene was the principal reaction product, with pentachloroethane (PCA) as a minor intermediate and trichloroethylene, cis-1,2-dichloroethylene, and acetylene as minor products. Detection of PCA and the insensitivity of the reaction to numerous inorganic and organic solution species is consistent with an outersphere HCA dechlorination pathway involving two successive one-electron transfers. 2,2′-Bipyridine and 1,10-phenanthrolene significantly increased the rate of HCA dechlorination by FeS, which was explained by the participation of delocalized ﷿* molecular orbitals in the electron-transfer reaction. Cysteine and methionine were found to slow, but not stop, the reaction rate, and this was attributed to adsorption of thiol and sulfide functional groups to FeS surface iron atoms, causing an energetic or steric barrier to electron transfer. Rapid dechlorination rates and the insensitivity of the dechlorination reaction to numerous ionic and organic species suggest that FeS-mediated reductive dechlorination may be an important transformation pathway in natural systems.
Enhancing Social Interactions and Activity Among the Elderly Through Stimulus Control

The present study investigated the effectiveness of a stimulus control procedure (access to free coffee and cookies) in increasing attendance and interactions among elderly in a lounge area of a nursing home. Following a baseline period, residents were provided access to coffee and cookies. The results showed that the refreshments were effective in increasing attendance and interactions and in decreasing television watching. In addition, attendance and participation during a subsequent activity session increased. Attendance, interactions, and participation decreased during a return to baseline period, and increased again with reimplementation of treatment.
An Improved Procedure for the Epoxidation of Methyl Cinnamate Derivatives and Production of Acid Sensitive Epoxides

Abstract By using a biphasic epoxidation system, unreactive methyl cinnamate derivatives were epoxidized at higher rates, and epoxides that decomposed in the presence of m-chlorobenzoic acid (mCBA) to diol ester opening products under standard conditions were obtained in fair to excellent yields.
Acute Lung Injury with Endotoxin or NO2 Does Not Enhance Development of Airway Epithelium from Bone Marrow

Abstract Adult marrow-derived stem cells can localize to lung and acquire immunophenotypic characteristics of lung epithelial cells. Lung injury increases recruitment of the marrow-derived cells. We speculated that comparing patterns of lung engraftment following different lung injuries would provide insight into potential mechanisms by which marrow-derived cells were recruited to lung. To evaluate this, adult female C57Bl/6 mice irradiated and engrafted with marrow from adult male transgenic GFP mice were exposed to either intranasal inhalation of endotoxin (25 μg/mouse) or 3 days of 25 ppm NO 2 and then compared 1 or 3 months later to transplanted but otherwise uninjured mice. In all cases, the majority of marrow-derived cells recruited to lung were CD45 + leukocytes. In lungs of transplanted but otherwise uninjured mice, small numbers of CD45 − donor-derived cells in alveolar septae stained positively for pro-surfactant protein C. Rare donor-derived cells located in the airway epithelium stained positively with cytokeratin. Subsequent exposure of engrafted mice to NO 2 or endotoxin did not significantly increase the number or pattern of donor-derived CD45 − cells found in recipient lungs. These results suggest that NO 2 or endotoxin lung injury does not result in significant engraftment of marrow-derived cells in lung.
Asymmetric Eschenmoser–Claisen Rearrangement for Anti-β-Substituted γ,δ-Unsaturated Amino Acids

Optically active anti-beta-substituted gamma,delta-unsaturated amino acids are important synthetic building blocks in organic synthesis and for peptidomimetics. A novel asymmetric Eschenmoser-Claisen rearrangement with use of a C2-symmetric chiral auxiliary was developed to generate this type of amino acid. Excellent diastereoselectivities and high enantioselectivities (87-93% ee) were obtained after the chiral auxiliary was removed via iodolactonization/zinc reduction.
Beyond bonus or bomb: upholding the sexual and reproductive health of young people

Abstract Described as a blessing or a curse, a bonus or a bomb, the youthful population boom in the global South is thought to be the catalyst of present and future social change on a massive scale. These binary understandings of youth are popular among proponents of development programs aimed at young people, including for family planning. But dualistic, numbers-based theories oversimplify a much more complex picture. They narrow our perceptions of young populations and, when lacking more detailed understanding based in youth experience, have the potential to constrict sexual and reproductive health and rights. Instead, youth-friendly, inclusive sexual and reproductive health policy should build from young peoples’ visions and diverse realities. Resume Decrite comme une benediction ou une malediction, un cadeau ou une bombe, l’explosion de la population jeune dans les pays du Sud est consideree comme le catalyseur du changement social present et futur sur une echelle massive. Ces conceptions binaires de la jeunesse sont populaires parmi les promoteurs de programmes de developpement destines aux jeunes, notamment la planification familiale. Mais les theories dualistes, fondees sur des chiffres, simplifient excessivement un tableau beaucoup plus complexe. Elles reduisent nos interpretations des populations jeunes et, lorsqu’il leur manque une comprehension plus detaillee fondee sur l’experience des jeunes, elles ont le potentiel d’inhiber la sante et les droits sexuels et genesiques. Au contraire, une politique de sante sexuelle et genesique integratrice et axee sur les jeunes devrait etre fondee sur les idees des jeunes et leurs realites diverses.
Competition For Order Flow, Market Quality, And Price Discovery In The Nasdaq 100 Index Tracking Stock

We investigate competition for order flow, market quality, and price discovery in the Nasdaq 100 Index Tracking Stock (QQQ). The QQQ, an AMEX-listed, exchange-traded fund, is the most actively traded security in the U.S. equities market. On July 31, 2001, the NYSE began trading the QQQ, marking the first time it traded securities of companies it does not list. The greatest volume of trading takes place on electronic communication networks (ECNs), following by trading on the AMEX and the NYSE. Most of the block trades are executed on the AMEX, where the bid-ask spreads are narrower. We find that ECNs contribute the most to the price-discovery process. The spreads on all trading platforms have decreased and market quality and price discovery have improved since QQQ shares have traded on the NYSE.
The Revitalization of Older Industrial Cities: A Review Essay of Retooling for Growth

This review essay debates the policy issues raised by the book Retooling for Growth: Building a 21 st Century Economy in America’s Older Industrial Areas, edited by Richard M.
The Sum of a Finite Group of Weights of a Hopf Algebra

Motivated by the orthogonality relations for irreducible characters of a finite group, we evaluate the sum of a finite group of linear characters of a Hopf algebra, at all grouplike and skew-primitive elements. We then discuss results for products of skew-primitive elements. Examples include groups, (quantum groups over) Lie algebras, the small quantum groups of Lusztig, and their variations (by Andruskiewitsch and Schneider).
A Hybrid Least Squares and Principal Component Analysis Algorithm for Raman Spectroscopy

Raman spectroscopy is a powerful technique for detecting and quantifying analytes in chemical mixtures. A critical part of Raman spectroscopy is the use of a computer algorithm to analyze the measured Raman spectra. The most commonly used algorithm is the classical least squares method, which is popular due to its speed and ease of implementation. However, it is sensitive to inaccuracies or variations in the reference spectra of the analytes (compounds of interest) and the background. Many algorithms, primarily multivariate calibration methods, have been proposed that increase robustness to such variations. In this study, we propose a novel method that improves robustness even further by explicitly modeling variations in both the background and analyte signals. More specifically, it extends the classical least squares model by allowing the declared reference spectra to vary in accordance with the principal components obtained from training sets of spectra measured in prior characterization experiments. The amount of variation allowed is constrained by the eigenvalues of this principal component analysis. We compare the novel algorithm to the least squares method with a low-order polynomial residual model, as well as a state-of-the-art hybrid linear analysis method. The latter is a multivariate calibration method designed specifically to improve robustness to background variability in cases where training spectra of the background, as well as the mean spectrum of the analyte, are available. We demonstrate the novel algorithm’s superior performance by comparing quantitative error metrics generated by each method. The experiments consider both simulated data and experimental data acquired from in vitro solutions of Raman-enhanced gold-silica nanoparticles.
Formal [3+3]- and [3+2]-cycloadditions of allylsilanes with benzylic cations

Abstract Allylsilanes serve as three-carbon dipole equivalents for the formation of tetrahydronaphthalenes via Lewis-acid promoted formal [3+3]-cycloadditions with benzylic cations. A competing [3+2]-pathway resulted in the formation of dihydro(1 H )indenes. Both quinone methides and benzylic alcohols were used as precursors to the benzylic cations.
Heegaard Floer homology of certain mapping tori

We calculate the Heegaard Floer homologies HF + (M, s) for mapping tori M associated to certain surface diffeomorphisms, where s is any Spin c structure on M whose first Chern class is non-torsion. Let γ and δ be a pair of geometrically dual nonseparating curves on a genus g Riemann surfaceg, and let σ be a curve separatingg into components of genus 1 and g −1. Write t, t�, and tfor the right-handed Dehn twists about each of these curves. The examples we consider are the mapping tori of the diffeomorphisms t m ◦ t n for m, n ∈ Z and that of t ±1 � . AMS Classification 57R58; 53D40
On presentations of integer polynomial points of simple groups over number fields

Let K be a number field and let A be its ring of integers. Let G be a connected, noncommutative, absolutely almost simple algebraic K-group. If the K-rank of G equals 2, then G(A[t]) is not finitely presented.
Physical activity and mortality in postmenopausal women.

Objective. —To evaluate the association between physical activity and all-cause mortality in postmenopausal women. Design. —Prospective cohort study with 7 years of follow-up through December 31, 1992. Setting and Participants. —Subjects were 40 417 postmenopausal Iowa women, aged 55 to 69 years at baseline in 1986. Physical activity was assessed by mailed questionnaire. Main Outcome Measure. —All-cause mortality (n=2260). Results. —After adjustment for potential confounders and excluding women who reported having cancer or heart disease and those who died in the first 3 years of follow-up, women who reported regular physical activity were at significantly reduced risk of death during follow-up compared with women who did not (relative risk [RR], 0.77; 95% confidence interval [CI], 0.66-0.90). Increasing frequency of moderate physical activity was associated with reduced risk of death during follow-up (from rarely or never engaging in activity to activity at least 4 times per week, RRs, 1.0 [referent], 0.76, 0.70, and 0.62; P value for trend P value for trend=.06). Reduced risks of death with increased physical activity were evident for cardiovascular diseases (n=729) and respiratory illnesses (n=147). Women who engaged only in moderate but not vigorous physical activity also benefited, with moderate activity as infrequently as once per week demonstrating a reduced mortality risk of 0.78 (95% CI, 0.64-0.96). Conclusions. —These results demonstrate a graded, inverse association between physical activity and all-cause mortality in postmenopausal women. These findings strengthen the confidence that population recommendations to engage in regular physical activity are applicable to postmenopausal women.
Carbonyldiimidazole-mediated Lossen rearrangement

Carbonyldiimidazole (CDI) was found to mediate the Lossen rearrangement of various hydroxamic acids to isocyanates. This process is experimentally simple and mild, with imidazole and CO(2) being the sole stoichiometric byproduct. Significant for large-scale application, the method avoids the use of hazardous reagents and thus represents a green alternative to standard processing conditions for the Curtius and Hofmann rearrangements.
Interior Optima and the Inada Conditions

Abstract We present a new proof of the interiority of the policy function based on the Inada conditions. It is based on supporting properties of concave functions.
Cure-rate estimation under Case-1 interval censoring

Abstract We consider nonparametric estimation of cure-rate based on mixture model under Case-1 interval censoring. We show that the nonparametric maximum-likelihood estimator (NPMLE) of cure-rate is non-unique as well as inconsistent, and propose two estimators based on the NPMLE of the distribution function under this censoring model. We present a cross-validation method for choosing a ‘cut-off’ point needed for the estimators. The limiting distributions of the latter are obtained using extreme-value theory. Graphical illustration of the procedures based on simulated data is provided.
Genetic basis for phenotypic differences between different Toxoplasma gondii type I strains

Toxoplasma gondii has a largely clonal population in North America and Europe, with types I, II and III clonal lineages accounting for the majority of strains isolated from patients. RH, a particular type I strain, is most frequently used to characterize Toxoplasma biology. However, compared to other type I strains, RH has unique characteristics such as faster growth, increased extracellular survival rate and inability to form orally infectious cysts. Thus, to identify candidate genes that could account for these parasite phenotypic differences, we determined genetic differences and differential parasite gene expression between RH and another type I strain, GT1. Moreover, as differences in host cell modulation could affect Toxoplasma replication in the host, we determined differentially modulated host processes among the type I strains through host transcriptional profiling. Through whole genome sequencing, we identified 1,394 single nucleotide polymorphisms (SNPs) and insertions/deletions (indels) between RH and GT1. These SNPs/indels together with parasite gene expression differences between RH and GT1 were used to identify candidate genes that could account for type I phenotypic differences. A polymorphism in dense granule protein, GRA2, determined RH and GT1 differences in the evasion of the interferon gamma response. In addition, host transcriptional profiling identified that genes regulated by NF-ĸB, such as interleukin (IL)-12p40, were differentially modulated by the different type I strains. We subsequently showed that this difference in NF-ĸB activation was due to polymorphisms in GRA15. Furthermore, we observed that RH, but not other type I strains, recruited phosphorylated IĸBα (a component of the NF-ĸB complex) to the parasitophorous vacuole membrane and this recruitment of p- IĸBα was partially dependent on GRA2. We identified candidate parasite genes that could be responsible for phenotypic variation among the type I strains through comparative genomics and transcriptomics. We also identified differentially modulated host pathways among the type I strains, and these can serve as a guideline for future studies in examining the phenotypic differences among type I strains.
A Linear Synthesis of Branched High-Mannose Oligosaccharides from the HIV-1 Viral Surface Envelope Glycoprotein gp120

Described is a linear solution-phase synthesis of the HIV-1 viral surface envelope glycoprotein gp120 high-mannose nonasaccharide pentyl glycoside. Envisioning the automated solid-phase assembly of complex carbohydrates, the synthesis of the nonasaccharide and the related tri- and hexamannosides demonstrates the facile assembly of highly branched structures in a stepwise fashion incorporating monosaccharide building blocks. A differentially protected core trisaccharide was prepared and further elongated in two high-yielding tri-mannosylations to furnish the triantennary structure. The tri-, hexa-, and nonamannoside n-pentyl glycosides obtained via the described synthesis are currently being used for detailed study of the carbohydrate protein interactions responsible for binding of the anti-HIV protein cyanovirin-N to the glycoprotein gp120. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)
An inverse source problem in optical molecular imaging

We study the direct and an inverse source problem for the radiative transfer equation arising in optical molecular imaging. We show that for generic absorption and scattering coefficients, the direct problem is well-posed and the inverse one is uniquely solvable, with a stability estimate.
The Mishnah and Jewish dirigisme

Presents evidence from the literature that Jews are generally to be found on the left side of the political economic spectrum. Various thories have been put foward to explain this phenomenon: historical accident, reaction to stereotypes, intellectualism, and the Mishnah. Concludes that Jews, even orthodox ones, are liberals and leftists.
Dynamical tide in solar-type binaries

Circularization of late-type main-sequence binaries is usually attributed to turbulent convection, while that of early-type binaries is explained by resonant excitation of g-modes. We show that the latter mechanism also operates in solar-type stars and is at least as effective as convection despite inefficient damping of g-modes in the radiative core. The maximum period at which this mechanism can circularize a binary composed of solar-type stars in 1010 yr is as low as 3 days, if the modes are damped by radiative diffusion only and g-mode resonances are fixed, or as high as 6 days if one allows for evolution of the resonances and for nonlinear damping near inner turning points. Even the larger theoretical period falls short of the observed transition period by a factor of 2.
Relativistic effects in homogeneous gold catalysis

Transition-metal catalysts containing gold present new opportunities for chemical synthesis, and it is therefore not surprising that these complexes are beginning to capture the attention of the chemical community. Cationic phosphine-gold(i) complexes are especially versatile and selective catalysts for a growing number of synthetic transformations. The reactivity of these species can be understood in the context of theoretical studies on gold; relativistic effects are especially helpful in rationalizing the reaction manifolds available to gold catalysts. This Review draws on experimental and computational data to present our current understanding of homogeneous gold catalysis, focusing on previously unexplored reactivity and its application to the development of new methodology.
Modeling and Experimental Testing of a Smart Composite Bridge

An all composite bridge with integral sensor network has been designed and built at the University of Missouri-Rolla (UMR). An extensive experimental study and finite element analysis were carried out to obtain and compare properties (stiffness, strength, failure modes) of 76 mm (3 in) square hollow pultruded Fiber Reinforced Polymer (FRP) tubes and their assemblies. Tube assemblies were used in the fabrication of bridge deck designed for H-20 truckloads as specified by the American Association of State Highway and Transportation Officials (AASHTO). The bridge is 9.14 m (30 ft) long and is 2.74 m (9 ft) wide. All the coupons were tested under three- or four-point bending. Experimental results show excellent linear elastic behavior up to failure and are in good agreement with finite element solutions. A quarter portion of the full-sized bridge deck was then tested for its structural performance under design and fatigue loading and also for ultimate load capacity to evaluate the bridge response. The characteristics of the full-size bridge deck were determined by analyzing the performed tests. The test sample showed almost no reduction in stiffness or strength after 2 million cycles of fatigue loading in excess of the design load. The bridge was installed at the UMR campus in July 2000. The bridge is equipped with fiber optic sensors, and the response of the bridge will be remotely monitored.
Highly Selective Formation of tert‐Butyl Hydroperoxide from the Reaction of Isobutane and O2 in a Zeolite under Visible Light

Isobutane and oxygen gas loaded into zeolite BaY react upon irradiation with green or blue light to yield tert-butyl hydroperoxide in a single-photon process. This was discovered when monitoring the reaction at room temperature in situ by FT-infrared spectroscopy. Selectivity was 98%, even upon conversion of more than half of the reactants loaded into the zeolite. Diffuse reflectance spectra revealed a visible absorption tail which originates from an isobutane · O2 collision complex. It is attributed to the isobutane · O2 contact charge-transfer absorption, whose onset is shifted from the UV into the visible region by the high electrostatic field of the zeolite.
Retention of configuration in the desilylative hydroxyalkylation of α-silyl sulfides

Abstract The C-Si bond α to sulfur is replaced with retention of configuration when an α-silyl sulfide is treated with tetrabutylammonium fluoride in the presence of benzaldehyde.
Market structure, pigouvian taxation, and welfare

Using a short-run partial equilibrium model of social welfare, this paper examines the social welfare implications of changing Pigouvian taxes under three markets: perfect competition, monopoly, and Cournot oligopoly. The result for perfect competition supports the earlier finding that Pigouvian taxation increases social welfare [Buchanan, 1969]. However, in contrast to the previous result that Pigouvian taxes lower welfare under monopoly, the authors show that if the noncompetitive distortion is small, these taxes might still be useful in correcting monopoly-generated externalities and in improving social welfare. Cournot firms react to the tax depending upon their individual perceptions of the gain in post-tax marginal revenue. Policy implications of the study's results are discussed.
Fuel Molecular Structure and Flame Temperature Effects on Soot Formation in Gas Turbine Combustors

A systematic study of soot formation along the centerlines of axisymmetric laminar diffusion flames of a large number of liquid hydrocarbons, hydrocarbon blends, and aviation turbine and diesel fuels was made. The developed empirical relationship between soot volume fractions and fuel smoke point and hydrogen-to-carbon ratio was applied to five different combustor radiation data, and good agreement was obtained
The Orbit and Occultations of KH 15D

The unusual flux variations of the pre-main-sequence binary star KH 15D have been attributed to occultations by a circumbinary disk. We test whether or not this theory is compatible with newly available data, including recent radial velocity measurements, CCD photometry over the past decade, and photographic photometry over the past 50 years. We find the model to be successful, after two refinements: a more realistic motion of the occulting feature and a halo around each star that probably represents scattering by the disk. The occulting feature is exceptionally sharp edged, raising the possibility that the dust in the disk has settled into a thin layer and providing a tool for fine-scale mapping of the immediate environment of a T Tauri star. However, the window of opportunity is closing, as the currently visible star may be hidden at all orbital phases by as early as 2008.
A Search for Water Ice at the Lunar Poles with Clementine Images

Abstract Optical and near-IR signatures of water ice on the Moon's surface were sought in the permanently shadowed regions near its poles. Significant amounts of multiply-scattered radiation partly illuminate primary shadows cast by craters and other features. If there is water ice in the permanently shadowed regions of the Moon's surface, its spectral signature should appear in this multiply-scattered light. This investigation can be done most effectively with observations obtained by spacecraft, because most selenocentric positions occupied by the Earth will also be occupied by the Sun at some point in time, and because the lunar poles are seen only obliquely to a terrestrial observer. Images obtained by Clementine are particularly well-suited to this task, because the spacecraft's polar orbit allowed images of the poles to be acquired on nearly every orbit, resulting in literally thousands of images taken within a few degrees of each pole, and because the filters on the ultraviolet-visual camera (UVVIS) and the near infrared camera (NIR) occur at major absorption bands or within important continuum features of water ice. Approximately 5800 images obtained by the UVVIS camera and 1800 images obtained by the NIR camera were calibrated and combined into coadded mosaics to create multispectral maps of the lunar poles with the highest possible signal-to-noise. Unfortunately, analysis of our UVVIS mosaics indicates that any possible signal from multiply-scattered light in primary shadows was overwhelmed by instrumental stray light. For the NIR camera, we were able to determine the normalized reflectance of several regions that were identified by Margot et al. (1999, Science284, 1658–1660) as permanent shadows. We have identified one permanently shadowed crater with a 1.5-μm band spectral signature indicative of between 2.5 and 21% fractional coverage of H2O frost. However, the same region shows a 2.0 μm spectral signature that is inconsistent with the presence of any water.
Implications for the technology of high voltage solar arrays: The possibility of an arc resistant cell

Abstract All solar arrays have biased surfaces which can be exposed to the space environment. It has been observed that when the array bias is less than a few hundred volts negative then the exposed conductive surfaces may undergo arcing in the space plasma. A theory for arcing has been developed on these high voltage solar arrays which ascribes the arcing to electric field runaway at the interface of the plasma, conductor and solar cell dielectric. The theory was compared in detail to the experimental data and shown to give a reasonable explanation for the data. The theory suggests that overhanging the coverglass over the triple junction will modify the field runaway. It is shown that there is a critical overhang beyond which field runaway is unlikely to occur in space and therefore arcing will be suppressed.
Regioselective Reductive Cross-Coupling Reactions of Unsymmetrical Alkynes

The present microreview summarizes our progress over the last few years in defining regioselective reductive cross-coupling reactions of unsymmetrical alkynes with terminal- and internal alkynes, aldehydes, and imines. We begin with a brief historical perspective of metal-mediated reductive dimerization reactions of aromatic alkynes and discuss the challenges associated with “crossed” versions of this mode of reactivity. Next, a collection of available methods that allow for regioselective reductive cross-coupling of internal alkynes with terminal and internal alkynes, aldehydes, and imines is summarized. After an examination of the requirements for regioselectivity in these cases, the logic behind our design of alkoxide-directed titanium-mediated reductive cross-coupling reactions is presented. A nomenclature is introduced to delineate the presumed mechanistic origin of regioselection associated with each reaction design, and a presentation of alkoxide-directed regioselective reductive cross-coupling reactions of alkynes follows. Throughout, principal issues related to reactivity and selectivity are discussed to assess scope and limitations of available methods and to describe the broad challenges that exist for defining complex fragment union reactions based on reductive cross-coupling chemistry.
Analysis of Turbulent Flow Past a Class of Semi-Infinite Bodies

This study was undertaken with the primary purpose of developing an analysis for flow past a class of two-dimensional and axisymmetric semi-infinite bodies. The time-averaged Navier-Stokes equations for these flows are derived in surface-oriented conformal coordinates (ξ, η) in terms of similarity-type vorticity and stream-function variables. Turbulence closure is achieved by means of a two-equation turbulence model utilizing the kinetic energy k and its dissipation rate e which enable determination of the isotropic eddy viscosity. The coupled vorticity and stream-function equations are solved simultaneously using an incremental formulation of the factored alternating-direction implicit scheme. The turbulence equations for k and e are solved by the standard ADI method. Numerical solutions are obtained for the thin flat plate and compared with available experimental and analytical data. Also, results are obtained for flow over a parabola and compared with the flat-plate results in order to assess the effects of longitudinal curvature on the flow results. Finally, solutions are obtained for flow past a two-dimensional semi-infinite body with a shoulder, at Red = 24,000. The computed results have the same general trend as the experimental data; possible causes for the differences within the separated-flow region are cited.
Potentials with Two Shifted Sets of Equally Spaced Eigenvalues and Their Calogero Spectrum

Abstract Motivated by the concept of shape invariance in supersymmetric quantum mechanics, we obtain potentials whose spectrum consists of two shifted sets of equally spaced energy levels. These potentials are similar to the Calogero-Sutherland model except that the singular term αx −2 always falls in the transition region −1 4 3 4 and there is a δ-function singularity at x = 0.
Decomposition of NH3 on Ir(100): A Temperature Programmed Desorption Study

Ammonia adsorption has been studied on an Ir(100) surface in the temperature range 100−410 K. In contrast to previous studies on Ir(111), approximately 12% of the chemisorbed ammonia undergoes stepwise decomposition at 200 K. However, decomposition has been found to be an activated process wherein a difference in the activation energy of dissociation and desorption is estimated to be 21 kJ/mol. Recombinative nitrogen desorption, occurring at temperature as low as 500 K, has been found to be the crucial step for having continuous and efficient ammonia decomposition with an activation energy of 64 kJ/mol. Coadsorption of hydrogen and ammonia have been carried out to understand the partial pressure dependences for ammonia decomposition---0.9 ± 0.1 with respect to ammonia and −0.7 ± 0.1 with respect to hydrogen. Coadsorption data indicate that the negative order with respect to hydrogen is due to enhancement of the reverse reaction (NHx + H → NHx+1, x = 0−2) as well as reduction in the desorption temperature ...
Space-efficient simulation of quantum computers

Traditional algorithms for simulating quantum computers on classical ones require an exponentially large amount of memory, and so typically cannot simulate general quantum circuits with more than about 30 or so qubits on a typical PC-scale platform with only a few gigabytes of main memory. However, more memory-efficient simulations are possible, requiring only polynomial or even linear space in the size of the quantum circuit being simulated. In this paper, we describe one such technique, which was recently implemented at FSU in the form of a C++ program called SEQCSim, which we releasing publicly. We also discuss the potential benefits of this simulation in quantum computing research and education, and outline some possible directions for further progress.
Urban Protest in Burkina Faso

Burkina Faso has embarked on a course of decentralization in which elected local governments are assuming a share of decision making over a range of services and activities previously under central authority. But many of these municipalities have also become sites and targets of popular contestation, a reality that has rarely been acknowledged in the official discourses of decentralized governance. By employing social movement research methods, this article examines more than 200 public demonstrations, marches, sit-ins, strikes, riots, and other forms of protest over local issues in 31 of Burkina's urban municipalities, from 1995 to 2007. It finds that both local government reactions and the protests themselves are strongly influenced by the national political context. The analysis highlights some of the main grievances raised by protesters, from opposition to police violence and merchants’ frustrations over the management of marketplaces, to residents’ concerns about municipal corruption and resistance to neighbourhood displacement resulting from urban ‘modernization’ schemes. By challenging the performance of Burkina's municipal councils and mayors, ordinary residents are exercising ‘voice’ and seeking to give some real substance to notions of participatory decentralization.
Recent Advances in III‐Nitride Devices Grown on Lithium Gallate

Recent advances in the growth of III-nitride materials and devices include: (i) The reduction of the near-surface threading dislocation density in GaN on lithium gallate (LGO) to 2 × 10 7 cm -2 . (ii) The demonstration of GaN, 50 × 130 μm, metal-semiconductor-metal (MSM) photodiodes with extremely low leakage current, 0.11 pA at 2 V and 7.9 pA at 60 V, and UV photoresponse at 308 nm and 20 V of 0.105 A/W. (iii) State of the art MSM devices have been successfully removed from the LGO substrate and attached to silicon wafers with no degradation in current characteristics. (iv) Demonstration of very thin, 0.7 μm HFET structures, grown at a rapid rate of 0.9 μm/h, with near state of the art room temperature 2DEG mobilities of 1365 cm 2 /Vs at a sheet charge of 9 x 10 12 cm -2 . (v) The elimination of substrate impurity diffusion by inclusion of gettering buffers has also been demonstrated.
Dynamic generators of topologically embedded graphs

We provide a data structure for maintaining an embedding of a graph on a surface (represented combinatorially by a permutation of edges around each vertex) and computing generators of the fundamental group of the surface, in amortized time O(log n + log g(log log g)3) per update on a surface of genus g; we can also test orientability of the surface in the same time, and maintain the minimum and maximum spanning tree of the graph in time O(log n + log4g) per update. Our data structure allows edge insertion and deletion as well as the dual operations; these operations may implicitly change the genus of the embedding surface. We apply similar ideas to improve the constant factor in a separator theorem for low-genus graphs, and to find in linear time a tree-decomposition of low-genus low-diameter graphs.
A Two-Dimensional Cylindrical Transient Conduction Solution Using Green's Functions

There are many applications for problems involving thermal conduction in two-dimensional cylindrical objects. Experiments involving thermal parameter estimation are a prime example, including cylindrical objects suddenly placed in hot or cold environments. In a parameter estimation application, the direct solution must be run iteratively in order to obtain convergence with the measured temperature history by changing the thermal parameters. For this reason, commercial conduction codes are often inconvenient to use. It is often practical to generate numerical solutions for such a test, but verification of custom-made numerical solutions is important in order to assure accuracy. The present work involves the generation of an exact solution using Green’s functions where the principle of superposition is employed in combining a one-dimensional cylindrical case with a one-dimensional Cartesian case to provide a temperature solution for a two-dimensional cylindrical. Green’s functions are employed in this solution in order to simplify the process, taking advantage of the modular nature of these superimposed components. The exact solutions involve infinite series of Bessel functions and trigonometric functions but these series sometimes converge using only a few terms. Eigenvalues must be determined using Bessel functions and trigonometric functions. The accuracy of the solutions generated using these series is extremely high, being verifiable to eight or ten significant digits. Two examples of the solutions are shown as part of this work for a family of thermal parameters. The first case involves a uniform initial condition and homogeneous convective boundary conditions on all of the surfaces of the cylinder. The second case involves a nonhomogeneous convective boundary condition on a part of one of the planar faces of the cylinder and homogeneous convective boundary conditions elsewhere with zero initial conditions.Copyright © 2013 by ASME
Expedient synthesis and solvent dependent oxidation behavior of a water-soluble IBX derivative

IBX derivative 6, synthesized in two steps from 2-aminoterephthalic acid, 8, is soluble in both DMF and water. A variety of alcohols are oxidized using 6 in DMF with ease and selectivity identical to that of parent IBX. However, oxidations carried out in water and other aqueous solvent mixtures using 6 exhibit unique selectivities toward different substrates and provide products different from reactions carried out in DMF. A mechanistic rationale is provided for this solvent dependent behavior of 6.
A Novel Synthesis of 1-Aminoalkylphosphonates

Abstract A nover route has been devised ofr the preparation of a series of 1-aminoalkylphosphonate deisters, precursors to analogues of a-amino acids. The route involves a ficile bromine subsititution at the 1-position of alkylphonate diesters using N-bromisuccinimide, followed by azide ion displacement and catalytic hydrogenolysis.
On the Low-SNR Capacity of Phase-Shift Keying with Hard-Decision Detection

The low-SNR capacity of M-ary PSK transmission over both the additive white Gaussian noise (AWGN) and fading channels is analyzed when hard-decision detection is employed at the receiver. Closed-form expressions for the first and second derivatives of the capacity at zero SNR are obtained. The spectral-efficiency/bit-energy tradeoff in the low-SNR regime is analyzed by finding the wideband slope and the bit energy required at zero spectral efficiency. Practical design guidelines are drawn from the information-theoretic analysis. The fading channel analysis is conducted for both coherent and noncoherent cases, and the performance penalty in the low-power regime for not knowing the channel is identified.
Long-term relationships as safeguards

We analyze a repeated prisoners’ dilemma game played in a community setting with heterogeneous types. The setting is such that individuals choose whether to continue interacting with their present partner, or separate and seek a new partner. Players’ types are not directly observed, but may be imperfectly inferred from observed behavior. We focus on a class of equilibria that satisfy zero tolerance and fresh start. We find that the punishment for defecting and the reward for cooperating are driven by the formation and the dissolution of long-term, high-paying relationships: an individual who defects, aborts a long-term relationship that he is in, or that he might have entered into, is thrown into short-term interactions with individuals who are likely to defect and, consequently, receives low payoffs. On the flip side, an individual who cooperates, enters into or prolongs a long-term interaction with a partner who cooperates and, consequently, receives high payoffs.
Multicomponent reactions in alkaloid-based drug discovery

Multicomponent reactions are emerging as a powerful tool in alkaloid-based drug discovery. This Highlight describes several recent (all published in 2011) examples of the employment of multicomponent reactions for the synthesis of biologically active alkaloids and their medicinally relevant analogues.
Bifunctional Catalyst Promotes Highly Enantioselective Bromolactonizations To Generate Stereogenic C–Br Bonds

A novel bifunctional catalyst derived from BINOL has been developed that promotes the highly enantioselective bromolactonizations of a number of structurally distinct unsaturated acids. Like some known catalysts, this catalyst promotes highly enantioselective bromolactonizations of 4- and 5-aryl-4-pentenoic acids, but it also catalyzes the highly enantioselective bromolactonizations of 5-alkyl-4(Z)-pentenoic acids. These reactions represent the first catalytic bromolactonizations of alkyl-substituted olefinic acids that proceed via 5-exo mode cyclizations to give lactones in which new carbon–bromine bonds are formed at a stereogenic center with high enantioselectivity. We also disclose the first catalytic desymmetrization of a prochiral dienoic acid by enantioselective bromolactonization.
The Baryon Fractions and Mass-to-Light Ratios of Early-Type Galaxies

We jointly model 22 early-type gravitational lens galaxies with stellar dynamical measurements using standard CDM halo models. The sample is inhomogeneous in both its mass distributions and the evolution of its stellar populations unless the true uncertainties are significantly larger than the reported measurement errors. In general, an individual system cannot constrain halo models, in the sense that the data poorly constrain the stellar mass fraction of the halo. An ensemble of systems, however, strongly constrains the average stellar mass represented by the visible galaxies to -->0.026 ± 0.006 of the halo mass if we neglect adiabatic compression, rising to -->0.056 ± 0.011 of the halo mass if we include adiabatic compression. Both estimates are significantly smaller than the global baryon fraction, corresponding to a star formation efficiency for early-type galaxies of 10%-30%. In the adiabatically compressed models, we find an average local B-band stellar mass-to-light ratio of -->(M/L)0 = 7.2 ± 0.5 M☉/L☉ that evolves as -->dlog (M/L)/dz = − 0.72 ± 0.08 per unit redshift. Adjusting the isotropy of the stellar orbits has little effect on the results. The adiabatically compressed models are strongly favored if we impose either local estimates of the mass-to-light ratios of early-type galaxies or weak-lensing measurements for the lens galaxies on 100 kpc scales as model constraints.
Radial Gas Flows in Colliding Galaxies: Connecting Simulations and Observations

We investigate the detailed response of gas to the formation of transient and long-lived dynamical structures induced in the early stages of a disk-disk collision, and identify observational signatures of radial gas inflow through a detailed examination of the collision simulation of an equal mass bulge dominated galaxy. Our analysis and discussion mainly focuses around the evolution of the diffuse and dense gas in the early stages of the collision, when the two disks are interacting but have not yet merged. Stars respond to the tidal interaction by forming both transient arms and long lived m = 2 bars, but the gas response is more transient, flowing directly toward the central regions within about 10 years after the initial collision. The rate of inflow declines when more than half of the total gas supply reaches the inner few kpc, where the gas forms a dense nuclear ring inside the stellar bar. The average gas inflow rate to the central 1.8 kpc is ∼ 7M⊙ yr −1 with a peak rate of 17M⊙ yr . Gas with high volume density is found in the inner parts of the post-collision disks at size scales close to the spatial resolution of the simulations, and this may be a direct result of shocks traced by the discontinuity in the gas velocity field. The evolution of gas in a bulgeless progenitor galaxy is also discussed, and a possible link to the “chain galaxy” population observed at high redshifts is inferred. The evolution of the structural parameters such as asymmetry and concentration of both stars and gas are studied in detail. Further, a new structure parameter (the compactness parameter K) that traces the evolution of the size scale of the gas relative to the stellar disk is introduced, and this may be a useful tracer to determine the merger chronology of colliding systems. Non-circular gas kinematics driven by the perturbation of the non-axisymmetric structure can produce distinct emission Department of Astronomy, University of Massachusetts, Amherst, MA 01002 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 Research Corporation Cottrell Scholar and NSF CAREER Fellow