cssi/SciSciGPT-SciSciNet huggingface dataset:
Wilson Loops in 2d Yang-Mills Euler Characters and Loop Equations

We give a simple diagrammatic algorithm for writing the chiral large N expansion of intersecting Wilson loops in 2D SU(N) and U(N) Yang-Mills theory in terms of symmetric groups, generalizing the result of Gross and Taylor for partition functions. We prove that these expansions compute Euler characters of a space of branched covering maps from string worldsheets with boundaries. We prove that the Migdal-Makeenko equations hold for the chiral theory and show that they can be expressed as linear constraints on perturbations of the chiral YM2 partition functions. We briefly discuss finite N, the nonchiral expansion, and higher-dimensional lattice models.
Synthesis of indolizine-5,8-diones and [3.2.2]cyclazines

Abstract The thermally induced ring expansion of 4-(1-pyrrolyl)-4-trimethylsiloxycyclobutenones to 5-hydroxy-8-trimethylsiloxyindolizines and their subsequent oxidation to the rare indolizine-5,8-diones is described. When the rearrangement is carried out in the presence of DMAD the indolizines are trapped in an 8+2 cycloaddition to give [3.2.2]cyclazines.
Throughput-smoothness tradeoff in preventing competing TCP from starvation

In this paper, we systematically study and demonstrate a fundamental tradeoff for TCP friendliness: in order for a congestion control protocol to maintain a certain degree of TCP friendliness, the longer its smoothness timescale is, the lower its average rate should be. Specifically, we derive the TCP-friendly rate requirements for three different smoothness timescales (i.e., milliseconds, seconds, and minutes) with flow-level queueing models, and verify the analytical results with extensive packet-level simulation results. Our flow-level queueing models indicate that the fundamental reason of the throughput-smoothness tradeoff is that TCP arrivals have different characteristics on different timescales. Finally, we propose a new TCP-friendly congestion control protocol for applications that prefer a smooth predictable rate on a multi-minute timescale, called Long-Time-Scale TCP-Friendly CBR-Like Rate Control (L-TFCBR).
Syria Contextualized: The Numbers Game

The popular discourse on the Syrian conflict has largely taken for granted that Bashar al-Asad and his regime are unpopular in Syria, the revolution is widely supported domestically, the rebels are “winning” the war, and the fall of the regime is inevitable and imminent. To justify their interpretation of the conflict, opposition activists, Western policy makers and media outlets make frequent reference to a number of “facts,” often statistical in nature. However, should we contextualize this data more rigorously, it becomes apparent that a radically different dynamic may be at work “on the ground” in Syria. This becomes important, as a more nuanced understanding of what is happening will have implications for what strategy the United States should pursue.
The Moduli of reducible vector bundles

A procedure for computing the dimensions of the moduli spaces of reducible, holomorphic vector bundles on elliptically fibered Calabi-Yau threefolds X is presented. This procedure is applied to poly-stable rank n+m bundles of the form V + pi* M, where V is a stable vector bundle with structure group SU(n) on X and M is a stable vector bundle with structure group SU(m) on the base surface B of X. Such bundles arise from small instanton transitions involving five-branes wrapped on fibers of the elliptic fibration. The structure and physical meaning of these transitions are discussed.
A comparison of some methodologies for the factor analysis of non‐normal Likert variables: A note on the size of the model

This paper expands on a recent study by Muthen & Kaplan (1985) by examining the impact of non-normal Likert variables on testing and estimation in factor analysis for models of various size. Normal theory GLS and the recently developed ADF estimator are compared for six cases of non-normality, two sample sizes, and four models of increasing size in a Monte Carlo framework with a large number of replications. Results show that GLS and ADF chi-square tests are increasingly sensitive to non-normality when the size of the model increases. No parameter estimate bias was observed for GLS and only slight parameter bias was found for ADF. A downward bias in estimated standard errors was found for GLS which remains constant across model size. For ADF, a downward bias in estimated standard errors was also found which became increasingly worse with the size of the model.
Electromagnetic response of a pinned Wigner crystal

A microscopic model for analyzing the microwave absorption properties of a pinned, two-dimensional Wigner crystal in a strong perpendicular magnetic field is developed. The method focuses on excitations within the lowest Landau level, and corresponds to a quantum version of the harmonic approximation. For pure systems (no disorder), the method reproduces known results for the collective mode density of states of this system, and clearly identifies the origin of previously unexplained structure in this quantity. The application of the method to a simple diagonal disorder model uncovers a surprising result: a sharp (\ensuremath{\delta}-function) response at zero temperature that is consistent with recent experiments. A simple spin lattice model is developed that reproduces the results of the quantum harmonic approximation, and shows that the sharp response is possible because the size scale ${L}_{c}$ of patches moving together in the lowest-frequency collective mode is extremely large compared to the sample size for physically relevant parameters. This result is found to be a direct repercussion of the long-range nature of the Coulomb interaction. Finally, the model is used to analyze different disorder potentials that may pin the Wigner crystal, and it is argued that interface disorder is likely to represent the dominant pinning source for the system. A simple model of the interface is shown to reproduce some of the experimental trends for the magnetic field dependence of the pinning resonance.
Synergy in parallel algorithms

A property of algorithms called synergy is introduced, and a quantity s, of synergy is defined. When synergized, both parallel and serial algorithms run faster, the parallel algorithms benefiting from a cooperation between processors. Examples show that synergy is a useful concept in the design of parallel algorithms.
A Lattice Boltzmann Scheme for Incompressible Multiphase Flow and Its Application in Simulation of Rayleigh-Taylor Instability

In this paper, we propose a new lattice Boltzmann scheme for simulation of multiphase flow in the nearly incompressible limit. The new scheme simulates fluid flows based on distribution functions. The interfacial dynamics, such as phase segregation and surface tension, are modeled by incorporating molecular interactions. The lattice Boltzmann equations are derived from the continuous Boltzmann equation with appropriate approximations suitable for incompressible flow. The numerical stability is improved by reducing the effect of numerical errors in calculation of molecular interactions. An index function is used to track interfaces between different phases. Simulations of the two-dimensional Rayleigh?Taylor instability yield satisfactory results. The interface thickness is maintained at 3?4 grid spacings throughout simulations without artificial reconstruction steps.
Farm Business-Owning Couples: Interrelationships among Business Tensions, Relationship Conflict Quality, and Spousal Satisfaction

The purpose of this study was to investigate the relationships among business tensions, relationship conflict quality, and satisfaction with spouse for 206 farm business-owning couples. The Sustainable Family Business Model and the Family FIRO (Fundamental Interpersonal Relations Orientation) model guided the path analysis. For both husbands and wives, locus of control was negatively related to business tensions; decision involvement discrepancy was positively related to relationship conflict quality; and business tensions were negatively related to relationship conflict quality. For husbands, relationship conflict quality was positively related to satisfaction with spouse; for wives, business tensions were negatively related to satisfaction with business-owning spouse.
Simulations of glitches in isolated pulsars

Many radio pulsars exhibit glitches wherein the star's spin rate increases fractionally by ∼10 - 1 0 -10 - 6 . Glitches are ascribed to variable coupling between the neutron star crust and its superfluid interior. With the aim of distinguishing among different theoretical explanations for the glitch phenomenon, we study the response of a neutron star to two types of perturbations to the vortex array that exists in the superfluid interior: (1) thermal motion of vortices pinned to inner crust nuclei, initiated by sudden heating of the crust, (e.g., a starquake), and (2) mechanical motion of vortices (e.g., from crust cracking by superfluid stresses). Both mechanisms produce acceptable fits to glitch observations in four pulsars, with the exception of the 1989 glitch in the Crab pulsar, which is best fitted by the thermal excitation model. The two models make different predictions for the generation of internal heat and subsequent enhancement of surface emission. The mechanical glitch model predicts a negligible temperature increase. For a pure and highly conductive crust, the thermal glitch model predicts a surface temperature increase of as much as ∼2 per cent, occurring several weeks after the glitch. If the thermal conductivity of the crust is lowered by a high concentration of impurities, however, the surface temperature increases by ∼10 per cent about a decade after a thermal glitch. A thermal glitch in an impure crust is consistent with the surface emission limits following the 2000 January glitch in the Vela pulsar. Future surface emission measurements coordinated with radio observations will constrain glitch mechanisms and the conductivity of the crust.
Model systems for flavoenzyme activity. A versatile synthesis of N(3)-alkylated flavins

Abstract Reaction of isoalloxazines (flavins) with primary and secondary alcohols using Mitsunobu conditions provides flavins alkylated at the N(3) position. This method provides a versatile and divergent synthesis of both primary alkyl flavins, and the difficult to synthesize secondary alkyl flavins.
Higher order properties of the wild bootstrap under misspecification

Abstract We examine the higher order properties of the wild bootstrap ( Wu, 1986 ) in a linear regression model with stochastic regressors. We find that the ability of the wild bootstrap to provide a higher order refinement is contingent upon whether the errors are mean independent of the regressors or merely uncorrelated with them. In the latter case, the wild bootstrap may fail to match some of the terms in an Edgeworth expansion of the full sample test statistic. Nonetheless, we show that the wild bootstrap still has a lower maximal asymptotic risk as an estimator of the true distribution than a normal approximation, in shrinking neighborhoods of properly specified models. To assess the practical implications of this result we conduct a Monte Carlo study contrasting the performance of the wild bootstrap with a normal approximation and the traditional nonparametric bootstrap.
Self-splicing and enzymatic activity of an intervening sequence RNA from Tetrahymena

A living cell requires thousands of different chemical reactions to utilize energy, move, grow, respond to external stimuli and reproduce itself. While these reactions take place spontaneously, they rarely proceed at a rate fast enough for life. Enzymes, biological catalysts found in all cells, greatly accelerate the rates of these chemical reactions and impart on them extraordinary specificity. In 1926, James B. Summer crystallized the enzyme urease and found that it was a protein. Skeptics argued that the enzymatic activity might reside in a trace component of the preparation rather than in the protein (Haldane, 1930), and it took another decade for the generality of Sumner's finding to be established. As more and more examples of protein enzymes were found, it began to appear that b~iological catalysis would be exclusively the realm of proteins. In 1981 and 1982, my research group and I found a case in which RNA, a form of genetic material, was able to cleave and rejoin its own nucleotide linkages. This self-splicing RNA provided the first example of a catalytic active site formed of ribonucleic acid. This lecture gives a personal view of the events that led to our realization of RNA self-splicing and the catalytic potential of RNA. It provides yet another illustration of the circuitous path by which scientific inquiry often proceeds. The decision to expend so many words describing the early experiments means that much of our current knowledge about the system will not be mentioned. For a more comprehensive view of the mechanism and structure of the Tetrahymena
Artin relations in the mapping class group

For every integer l ≥ 2, we find elements x and y in the mapping class group of an appropriate orientable surface S, satisfying the Artin relation of length l. That is, xyx ... = yxy ..., where each side of the equality contains l terms. By direct computations, we first find elements x and y in Mod(S) satisfying Artin relations of every even length ≥ 8, and every odd length ≥ 3. Then using the theory of Artin groups, we give two more alternative ways for finding Artin relations in Mod(S). The first provides Artin relations of every length ≥ 3, while the second produces Artin relations of every even length ≥ 6.
Toward a perception-based theory of probabilistic reasoning with imprecise probabilities

The perception-based theory of probabilistic reasoning which is outlined in this paper is not in the traditional spirit. Its principal aim is to lay the groundwork for a radical enlargement of the role of natural languages in probability theory and its applications, especially in the realm of decision analysis. To this end, probability theory is generalized by adding to the theory the capability to operate on perception-based information, e.g., “Usually Robert returns from work at about 6 p.m”, or “It is very unlikely that there will be a significant increase in the price of oil in the near future”. A key idea on which perception-based theory is based is that the meaning of a proposition, p, which describes a perception, may be expressed as a generalized constraint of the form X isγ R, where X is the constrained variable, R is the constraining relation and isγ is a copula in which γ is a discrete variable whose value defines the way in which R constrains X. In the theory, generalized constraints serve to define imprecise probabilities, utilities and other constructs, and generalized constraint propagation is employed as a mechanism for reasoning with imprecise probabilities as well as for computation with perception-based information.
3-butenyl esters as convenient protecting groups for carboxylic acids

Abstract Carboxylic acids were protected as their corresponding 3-butenyl esters. Deprotection was carried out via ozonolysis and β-elimination of the resultant 3-acyloxypropanal.
ZEROS OF WEAKLY HOLOMORPHIC MODULAR FORMS OF LEVEL 4

Let be the space of weakly holomorphic modular forms of weight k and level 4 that are holomorphic away from the cusp at ∞. We define a canonical basis for this space and show that for almost all of the basis elements, the majority of their zeros in a fundamental domain for Γ0(4) lie on the lower boundary of the fundamental domain. Additionally, we show that the Fourier coefficients of the basis elements satisfy an interesting duality property.
Synthesis of homoallylic alcohols via palladium-catalyzed coupling of organomercurials and vinylic oxetanes

Abstract The reaction of aryl- and vinylmercurials, cupric chloride, 5% aqueous NH4Cl, oxygen, catalytic amounts of Li2pPdCl4 and vinylic oxetanes affords an excellent route to functionally-substituted homoallylic alcohols.
Frequent recent origination of brain genes shaped the evolution of foraging behavior in Drosophila.

SUMMARY The evolution of the brain and behavior are coupled puzzles. The genetic bases for brain evolution are widely debated, yet whether newly evolved genes impact the evolution of the brain and behavior is vaguely understood. Here, we show that during recent evolution in Drosophila, new genes have frequently acquired neuronal expression, particularly in the mushroom bodies. Evolutionary signatures combined with expression profiling showed that natural selection influenced the evolution of young genes expressed in the brain, notably in mushroom bodies. Case analyses showed that two young retrogenes are expressed in the olfactory circuit and facilitate foraging behavior. Comparative behavioral analysis revealed divergence in foraging behavior between species. Our data suggest that during adaptive evolution, new genes gain expression in specific brain structures and evolve new functions in neural circuits, which might contribute to the phenotypic evolution of animal behavior.
Warp factors and extended sources in two transverse dimensions

Abstract We study the solutions of the Einstein equations in ( d +2)-dimensions, describing parallel p -branes ( p = d −1) in a space with two transverse dimensions of positive gaussian curvature. These solutions generalize the solutions of Deser and Jackiw of point particle sources in (2+1)-dimensional gravity with cosmological constant. Determination of the metric is reduced to finding the roots of a simple algebraic equation. These roots also determine the nontrivial “warp factors” of the metric at the positions of the branes. We discuss the possible role of these solutions and the importance of “warp factors” in the context of the large extra dimensions scenario.
Non-LTE treatment of FE II in astrophysical plasmas

Abstract We describe our implementation of an extremely detailed model atom of singly ionized iron for NLTE computations in static and moving astrophysical plasmas. Our model atom includes 617 levels, 13,675 primary permitted transitions and up to 1.2 million secondary transitions. Our approach guarantees that the total iron opacity is included at the correct wavelength with reasonable memory and CPU requirements. We find that the lines saturate the wavelength space, such that special wavelength points inserted along the detailed profile functions may be replaced with a statistical sampling method. We describe the results of various test calculations for novae and supernovae.
Partitioned estimation algorithms, II: Linear estimation

Abstract In a radically new approach to linear estimation, Lainiotis [33, 36–37, 52–53], using the “partition theorem”-an explicit Bayes theorem-obtained fundamentally new linear filtering and smoothing algorithms both for continuous as well as discrete data. The new algorithms are given in explicit, integral expressions of a “partitioned” form, and in terms of decoupled forward filters. The “partitioned” algorithms were shown to be especially advantageous from a computational as well as from an analysis standpoint. They are essentially based on the decomposition of the innovations into partial or conditional innovations and residuals. In this paper, the “partitioned” algorithms are shown to be the natural framework in which to study such important concepts as observability, controllability, unbiasedness, and the solution of Riccati equations. Specifically, in this paper, the “partitioned” algorithms are re-examined yielding further insight as well as several significant new results on: 1. (a) unbiased estimation and filter initialization procedures; 2. (b) stochastic observability and stochastic controllability; 3. (c) the interconnection between stochastic observability, Fisher information matrix, and the Cramer-Rao bound; 4. (d) estimation error-bounds; and most importantly 5. (e) computationally effective “partitioned” solutions of time-varying matrix Riccati equations. In fact, all of the above results have been obtained for general, time-varying, lumped, linear systems. In addition, it is shown that previously established smoothing algorithms, such as the Meditch differential algorithm and the Kailath-Frost total innovation algorithm, are readily obtained from the “partitioned” algorithms. The properties of the “partitioned” algorithms are obtained, thoroughly examined, and compared to those of other algorithms.
Prime to p extensions of the generic abelian crossed product

In this paper we prove that the non-cyclic generic abelian crossed product p-algebras constructed by Amitsur and Saltman in [S.A. Amitsur, D. Saltman, Generic Abelian crossed products and p-algebras, J. Algebra 51 (1) (1978) 76–87] remain non-cyclic after tensoring by any prime to p extension of their centers. We also prove that an example due to Saltman of an indecomposable generic abelian crossed product with exponent p and degree p2 remains indecomposable after any prime to p extension.
Decarboxylative Isomerization of N-Acyl-2-oxazolidinones to 2-Oxazolines

N-Acyl-2-oxazolidinones are ring-opened by lithium iodide and decarboxylated in the presence of a mild proton source. Further reaction with an amine base provides 2-oxazolines. The transformation is general for oxazolidinones unsubstituted in the 5 position and occurs under mild conditions (25−50 °C). These results complement the existing methods for this transformation by allowing lower temperatures and/or avoiding metal catalysts.
Curves vs. skeletons in object recognition

The type of representation used in describing shape can have a significant impact on the effectiveness and efficiency of a recognition strategy. Shape has been represented by a point set, outline curve and shock-graph (medial axis). The curve-based representation can be viewed as point-based representation with additional organization, namely, order along a contour; shock-based representation, in turn, Can be viewed as curve-based representation with additional organization, namely, pairing of contours. This additional complexity in organization leads to greater computational effort in deriving and matching these representations. However, it leads to an increase in robustness in the presence of variations. In This paper, we examine the tradeoff between robustness and computational complexity for curve-and shock-based representations. Our results indicate that the additional computational effort required in shock-graph matching is worthwhile in the presence of large amount variations, in particular those involving the presence of articulation or rearrangement of parts. However, when the space of variations is smaller, curve matching is a better strategy due to its lower complexity and roughly equivalent recognition rate.
Tris(trimethylsilyl) titanacyclobutene: A new mild reagent for the conversion of carbonyls to alkenyl silanes

Abstract Thermolysis of Cp 2 Ti(CH 2 SiMe 3 ) 2 in the presence of Me 3 SiCCSiMe 3 forms tris(trimethylsilyl) titanacyclobutene. Unlike other titanacyclobutenes which undergo insertion with carbonyl compounds, this reagent serves as a precursor to Cp 2 TiCHSiMe 3 , converting carbonyl compounds to the corresponding alkenyl silanes. This olefination takes place under mild conditions even at room temperature and works with aldehydes, ketones, esters, thioesters and lactones.
Learning Boolean Functions in an Infinite Attribute Space

This paper presents a theoretical model for learning Boolean functions in domains having a large, potentially infinite number of attributes. The model allows an algorithm to employ a rich vocabulary to describe the objects it encounters in the world without necessarily incurring time and space penalties so long as each individual object is relatively simple. We show that many of the basic Boolean functions learnable in standard theoretical models, such as conjunctions, disjunctions, K-CNF, and K-DNF, are still learnable in the new model, though by algorithms no longer quite so trivial as before. The new model forces algorithms for such classes to act in a manner that appears more natural for many learning scenarios.
Illustrative risks to the public in the use of computer systems and related technology

Copyright 2004, Peter G. Neumann, SRI International EL243, Menlo Park CA 94025-3493 (e-mail Neumann@csl.sri.com; http://www.CSL.sri.com/neumann; telephone 1-650-859-2375; fax 1-650-859-2844): Editor, ACM SIGSOFT Software Engineering Notes, 1976–93, Assoc.Ed., 1994–; Chairman, ACM Committee on Computers and Public Policy (CCPP); Moderator of the Risks Forum (comp.risks); cofounder with Lauren Weinstein of People For Internet Responsibility (http://www.pfir.org).
Saturating the bound on the scale of fermion mass generation

Abstract Recently, Jager and Willenbrock have shown that the Appelquist and Chanowitz bound on the scale of top-quark mass generation can formally be saturated at tree-level in a particular limit of a two-Higgs doublet model. In this note I present an alternate derivation of their result. I perform a coupled channel analysis for f f →V L V L and V L V L → V L V L scattering and derive the conditions on the parameters required for f f →V L V L scattering to be relevant to unitarity. I also show that it is not possible to saturate the bound on fermion mass generation in a two-Higgs model while maintaining tree-level unitarity in Higgs scattering at high energies.
A fault and seismicity based composite simulation in northern California

Abstract. We generate synthetic catalogs of seismicity in northern California using a composite simulation. The basis of the simulation is the fault based "Virtual California" (VC) earthquake simulator. Back-slip velocities and mean recurrence intervals are specified on model strike-slip faults. A catalog of characteristic earthquakes is generated for a period of 100 000 yr. These earthquakes are predominantly in the range M = 6 to M = 8, but do not follow Gutenberg-Richter (GR) scaling at lower magnitudes. In order to model seismicity on unmapped faults we introduce background seismicity which occurs randomly in time with GR scaling and is spatially associated with the VC model faults. These earthquakes fill in the GR scaling down to M = 4 (the smallest earthquakes modeled). The rate of background seismicity is constrained by the observed rate of occurrence of M > 4 earthquakes in northern California. These earthquakes are then used to drive the BASS (branching aftershock sequence) model of aftershock occurrence. The BASS model is the self-similar limit of the ETAS (epidemic type aftershock sequence) model. Families of aftershocks are generated following each Virtual California and background main shock. In the simulations the rate of occurrence of aftershocks is essentially equal to the rate of occurrence of main shocks in the magnitude range 4
syn Additions to 4α-Epoxypyranosides: Synthesis of l-Idopyranosides

The syn-selective addition of organozinc compounds to 4α-epoxypyranosides (4α-EPs), generated from methyl β-d-glucoside or aminoglucoside, provides an efficient route to pyranosides with α-l-ido configurations, including l-iduronic acid, neosamine B, and higher monosaccharide derivatives.
Hydrodimerization of unsaturated alcohols, esters, nitriles, ketones, amines, silanes, epoxides and fluorocarbons by mercury-photosensitization

Abstract Substituted alkenes are efficiently hydrodimerized on a preparative scale in an H 2 atmosphere by Hg(vapor) and 254 nm light.
Sparks and prairie fires: A theory of unanticipated political revolution

A feature shared by certain major revolutions is that they were not anticipated. Here is an explanation, which hinges on the observation that people who come to dislike their government are apt to hide their desire for change as long as the opposition seems weak. Because of this prefer- ence falsification, a government that appears unshakeable might see its support crumble following a slight surge in the opposition's apparent size, caused by events insignificant in and of them- selves. Unlikely though the revolution may have appeared in foresight, it will in hindsight appear inevitable because its occurrence exposes a panoply of previously hidden conflicts.
Structural insights into nonribosomal peptide enzymatic assembly lines

Nonribosomal peptides have a variety of medicinal activities including activity as antibiotics, antitumor drugs, immunosuppressives, and toxins. Their biosynthesis on multimodular assembly lines as a series of covalently tethered thioesters, in turn covalently attached on pantetheinyl arms on carrier protein way stations, reflects similar chemical logic and protein machinery to fatty acid and polyketide biosynthesis. While structural information on excised or isolated catalytic adenylation (A), condensation (C), peptidyl carrier protein (PCP) and thioesterase (TE) domains had been gathered over the past decade, little was known about how the NRPS catalytic and carrier domains interact with each other both within and across elongation or termination modules. This Highlight reviews recent breakthrough achievements in both X-ray and NMR spectroscopic studies that illuminate the architecture of NRPS PCP domains, PCP-containing didomain-fragments and of a full termination module (C-A-PCP-TE).
A Names-and-Faces Approach to Stakeholder Management How Focusing on Stakeholders as Individuals Can Bring Ethics and Entrepreneurial Strategy Together

Just as the ideas of stakeholder theory, stakeholder management, or stakeholder capitalism approach acceptance as a mainstream core idea in management theory, the authors want to suggest a somewhat...
Highly active oligomeric (salen)co catalysts for asymmetric epoxide ring-opening reactions.

Cooperative bimetallic catalysis has been documented in several recently reported asymmetric epoxide opening reactions that display second-order kinetic dependence on catalyst, specific requirements for multiple metal ions, and/or pronounced catalyst nonlinear effects.1 In such systems, one metal is proposed to serve as Lewis acid for epoxide activation and another as counterion for the nucleophile. In this mechanistic context, complexes that contain multiple metal centers in appropriate relative proximity and orientation can provide improved reactivity relative to monometallic catalysts. For example, chiral metal salen complexes such as 1 are effective catalysts for asymmetric epoxide ringopening reactions, and operate by a second-order mechanism.2 Linking these catalysts as dimers3 or to polymeric4 or dendrimeric5 frameworks leads to catalytic systems with similar enantioselectivity and substantially enhanced reactivity relative to 1. The synthetic utility of multimeric catalysts prepared in this manner is limited, however, by the inefficiency of their syntheses.6 We report here new, easily synthesized oligomeric analogues of 1 that exhibit not only remarkably enhanced reactivity, but also significantly higher enantioselectivity relative to 1.
Solid-phase peptide synthesis: a silver anniversary report

It has been a quarter of a century since Merrifield's initial report on solid-phase peptide synthesis. The field has matured significantly in recent years with a better understanding of the underlying chemistry. This is reflected by new, milder orthogonal protection schemes and more efficient coupling methods, some of which have been incorporated into automated systems. Advances in purification, especially high performance liquid chromatography, have had a major impact. The efficacy of these improvements has been demonstrated by an impressive litany of applications to biological problems.
The social consequences of automation

A comprehensive analysis of the impact of automation upon society would consider every sector of the social process. In the process of social interaction man pursues "value outcomes" through institutional practices utilizing resources. He pursues knowledge (enlightenment), political power, and various other value outcomes.
Dynamic superimposition of synthetic objects on rigid and simple-deformable real objects

Abstract A current challenge in augmented reality applications is the accurate superimposition of synthetic objects on real objects within the environment. This challenge is heightened when the real objects are in motion and/or are non-rigid. In this article, we present a robust method for real-time, optical superimposition of synthetic objects on dynamic, rigid and simple-deformable real objects. Moreover, we illustrate this general method with the VRDA Tool, a medical education application enabling the visualization of internal human knee joint anatomy on a real human knee.
Operationally Simple and Highly (E)-Styrenyl-Selective Heck Reactions of Electronically Nonbiased Olefins

Simple, mild, and efficient conditions are reported for a Pd0-catalyzed Heck reaction that delivers high yields and selectivity for (E)-styrenyl products using electronically nonbiased olefin substrates bearing a range of useful functionality. Preliminary mechanistic studies demonstrate that the σ-donating DMA solvent is crucial for high selectivity. Further studies suggest that the catalyst distinguishes between β-hydrogens on the basis of their relative hydridic character, in contrast to previously reported PdII-catalyzed oxidative reaction conditions.
Recent Progress of Phase Change Memory (PCM) and Resistive Switching Random Access Memory (RRAM)

The increasing demand for high-capacity non volatile memories in the electronic portable and media applications has required continuous scaling of the conventional FLASH memory technology beyond perceived limits. At the same time, system designers envision the use of novel memory technology may revolutionalize the organization of the memory hierarchy of processors and the design of SoC and SiP. This has resulted in the exploration of many alternate memory technologies like PCM, RRAM, STTRAM. In this paper we discuss some of our recent works on understanding the various aspects of PCM and RRAM.
An alkoxide-directed carbometalation of internal alkynes.

A mild and efficient alkoxide-directed carbometalation is described. Regioselective carbon−carbon bond formation occurs in all cases at the site distal to the tethered alkoxide. This reaction provides a convenient means to prepare differentially functionalized tetrasubstituted 1,3-dienes in a regio- and stereoselective manner.
Nuclear gluon distributions in a parton model

Abstract Gluon distributions in carbon and tin nuclei are investigated by using a Q2 rescaling model with parton recombination effects. We obtain strong shadowings in the small x region due to the recombinations. The ratio G A (x) G N (x) in the medium x region is typically 0.9 for medium size nuclei. At large x, the ratio becomes large due to gluon fusions from different nucleons. Comparisons with recent New Muon Collaboration data for G Sn (x) G C (x) indicate that more accurate experimental data are needed for testing the model.
Nonlocal density functionals and the linear response of the homogeneous electron gas

The known and usable truly nonlocal functionals for exchange-correlation energy of the inhomogeneous electron gas are the ADA (average density approximation) and the WDA (weighted density approximation). ADA, by design, yields the correct linear response function of the uniform electron gas. WDA is constructed so that it is exact in the limit of one-electron systems. We derive an expression for the linear response of the uniform gas in the WDA, and calculate it for several flavors of WDA. We then compare the results with the Monte-Carlo data on the exchange-correlation local field correction, and identify the weak points of conventional WDA in the homogeneous limit. We suggest how the WDA can be modified to improve the response function. The resulting approximation is a good one in both opposite limits, and should be useful for practical nonlocal density functional calculations.
Damping measurements using operational data

The authors have measured modal damping using strain-gauge data from an operating wind turbine. This new technique for measuring modal damping is easier and less expensive than previously used methods. Auto-correlation and cross-correlation functions of the strain-gauge data have been shown to consist of decaying sinusoids which correspond to the modal frequencies and damping ratios of the wind turbine. The authors have verified the method by extracting damping values from an analytically generated data set. Actual operating response data from the DOE/Sandia 34-m Test Bed has been used to calculate modal damping ratios as a function of rotor rotation rate. This capability will allow more accurate fatigue life prediction and control.
Radiative heat exchange and equilibrium surface temperature in a space environment.

An analysis is presented for evaluating radiant heat transfer and temperature of surfaces in a typical space environment. A semigray spectral subdivision of surface properties is employed to account for differences in property values for solar and surface radiation. In each spectral interval, a reflectance model with both diffuse and specular components is used to approximate the nondiffuse character of surface reflectance. An engineering formulation is given for a system of surfaces, some of which have prescribed temperature and the remainder prescribed radiant heat flux. The solution for flux or temperature, whichever is unknown, is given in terms of known temperatures, known fluxes, and certain ratios of determinants involving surface properties and geometry. The formulation is extended to include variation of flux and temperature on the surfaces. The analysis is applied to the adjoint plate system and results are presented for heat transfer and equilibrium temperature. Significant differences in heat transfer and equilibrium temperature occur between semigray analysis with the specular-diffuse reflectance model and that determined on the basis of gray diffuse theory.
Sequential hydrocarbon functionalization: allylic C-H oxidation/vinylic C-H arylation.

A Pd(II)/sulfoxide-catalyzed sequential allylic C−H oxidation/vinylic C−H arylation of α-olefins to furnish E-arylated allylic esters in high regio- and E:Z selectivities (>20:1) is reported. The broad scope of this method with respect to the α-olefin, carboxylic acid, and aryl boronic acid enables the rapid assembly of densely functionalized fragments for complex molecule synthesis from cheap, abundant hydrocarbon starting materials. The Pd(II)/sulfoxide-catalyzed vinylic C−H arylation of electronically unbiased olefins with aryl boronic acids proceeds under oxidative, acidic conditions and mild temperatures (room temperature to 45 °C).
An Introduction to the Theory of Dual Models and Strings

The theory of a free string is first presented classically and quantum mechanically both in a covariant and a nonexplicitly covariant treatment. Then the concepts and techniques obtained from the free string are used to build the operator formalism of dual models. Both the conventional Veneziano model and the Neveu-Schwarz-Ramond model are presented. The self-consistency of these models at the tree and loop levels is investigated, and the interpretation of the results obtained is given in terms of the string picture.
Gas of D-branes and Hagedorn density of BPS states

Abstract We test the prediction of a Hagedorn density of BPS states which carry RR charge in type II compactifications. We find that in certain cases they correspond to the supersymmetric ground states for a gas of identical 0-branes.
Does financial liberalization really improve private investment in developing countries

Assuming that liquidity constraints exist in most developing countries, the majority of analysts believe that increasing real interest rates will raise the volume of lending and hence private investment. The author, focusing on the demand for capital goods, argues that the positive effect on the domestic credit market may be offset by the negative effect of a portfolio shift from capital goods and public bonds into monetary assets. The author also demonstrates that a policy of financial liberalization could increase the public sector's demand for domestic credit, thus limiting the funds available to the private sector. This crowding out does not result from a change in the government's behavior but from a shift in the portfolio of private agents. Higher demand for bank deposits reduces the private sector's willingness to hold government bonds, so the public sector must finance a given budget deficit with more domestic credit. Simulations for Argentina for 1961 - 1982 suggest that the low response of private investors to changes in interest rate policy in those 20 years was attributable not to the low values of interest elasticities but to the interaction of the mechanisms allowed for in the model, which tends to neutralize the impact of such policies. The author concludes that the effect of changes in interest rate policy on the demand for capital goods is weak in Argentina and might affect the quality of private investment more than its quantity.
The Properties of Long-Period Variables in the Large Magellanic Cloud from MACHO

We present a new analysis of the long-period variables in the Large Magellanic Cloud (LMC) from the MACHO Variable Star Catalog. Three-quarters of our sample of evolved, variable stars have periodic light curves. We characterize the stars in our sample using the multiple periods found in their frequency spectra. Additionally, we use single-epoch Two Micron All Sky Survey measurements to construct the average infrared light curves for different groups of these stars. Comparison with evolutionary models shows that stars on the red giant branch (RGB) or the early asymptotic giant branch (AGB) often show non-periodic variability, but begin to pulsate with periods on the two shortest period-luminosity (P-L) sequences (3 & 4) when they brighten to K s ≈ 13. The stars on the thermally pulsing AGB are more likely to pulsate with longer periods that lie on the next two P-L sequences (1 & 2), including the sequence associated with the Miras in the LMC. The Petersen diagram and its variants show that multi-periodic stars on each pair of these sequences (3 & 4, and 1 & 2) typically pulsate with periods associated only with that pair. The periods in these multi-periodic stars become longer and stronger as the star evolves. We further constrain the mechanism behind the long secondary periods (LSPs) seen in half of our sample, and find that there is a close match between the luminosity functions of the LSP stars and all of the stars in our sample, and that these star's pulsation amplitudes are relatively wavelength independent. Although this is characteristic of stellar multiplicity, the large number of these variables is problematic for that explanation.
FORM FACTORS APPROACH TO CURRENT CORRELATIONS IN ONE-DIMENSIONAL SYSTEMS WITH IMPURITIES

Abstract We show how to compute analytically time and space dependent correlations in one-dimensional quantum integrable systems with an impurity. Our approach is based on a description of these systems in terms of massless scattering of quasi-particles. Correlators follow then from matrix elements of local operators between multiparticle states, the “massless form factors”. Although an infinite sum of these form factors has to be considered in principle, we find that for current, spin, and energy operators, only a few (typically two or three) are necessary to obtain an accuracy of more than 1%, for arbitrary coupling strength , that is all the way from short to large distances. As examples we compute, at zero temperature, the frequency-dependent conductance in a Luttinger liquid with impurity, the spectral function in the double-well problem of dissipative quantum mechanics and part of the space-dependent susceptibility in the Kondo model.
Formation of ArF from LPdAr(F): Catalytic Conversion of Aryl Triflates to Aryl Fluorides

Despite increasing pharmaceutical importance, fluorinated aromatic organic molecules remain difficult to synthesize. Present methods require either harsh reaction conditions or highly specialized reagents, making the preparation of complex fluoroarenes challenging. Thus, the development of general methods for their preparation that overcome the limitations of those techniques currently in use is of great interest. We have prepared [LPd(II)Ar(F)] complexes, where L is a biaryl monophosphine ligand and Ar is an aryl group, and identified conditions under which reductive elimination occurs to form an Ar-F bond. On the basis of these results, we have developed a catalytic process that converts aryl bromides and aryl triflates into the corresponding fluorinated arenes by using simple fluoride salts. We expect this method to allow the introduction of fluorine atoms into advanced, highly functionalized intermediates.
Del Pezzo Singularities and SUSY Breaking

An analytic construction of compact Calabi-Yau manifolds with del Pezzo singularities is found. We present complete intersection CY manifolds for all del Pezzo singularities and study the complex deformations of these singularities. An example of the quintic CY manifold with del Pezzo 6 singularity and some number of conifold singularities is studied in detail. The possibilities for the ‘‘geometric’’ and ISS mechanisms of dynamical SUSY breaking are discussed. As an example, we construct the ISS vacuum for the del Pezzo 6 singularity.
Optimal routing of energy-aware vehicles in networks with inhomogeneous charging nodes

We study the routing problem for vehicles with limited energy through a network of inhomogeneous charging nodes. This is substantially more complicated than the homogeneous node case studied in [1]. We seek to minimize the total elapsed time for vehicles to reach their destinations considering both traveling and recharging times at nodes when the vehicles do not have adequate energy for the entire journey. We study two versions of the problem. In the single vehicle routing problem, we formulate a mixed-integer nonlinear programming (MINLP) problem and show that it can be reduced to a lower dimensionality problem by exploiting properties of an optimal solution. We also obtain a Linear Programming (LP) formulation allowing us to decompose it into two simpler problems yielding near-optimal solutions. For a multi-vehicle problem, where traffic congestion effects are included, we use a similar approach by grouping vehicles into “subflows”. We also provide an alternative flow optimization formulation leading to a computationally simpler problem solution with minimal loss in accuracy.
Newton's method with deflation for isolated singularities of polynomial systems

We present a modification of Newton's method to restore quadratic convergence for isolated singular solutions of polynomial systems. Our method is symbolic-numeric: we produce a new polynomial system which has the original multiple solution as a regular root. Using standard bases, a tool for the symbolic computation of multiplicities, we show that the number of deflation stages is bounded by the multiplicity of the isolated root. Our implementation performs well on a large class of applications.
Towards highly improved quark actions

We describe two ideas useful in the construction of highly improved quark actions for simulations on coarse lattices: (i) Field transformations solve the doubler problem without destroying tree-level improvement for on- or off-shell quantities. The simplest example is the Sheikholeslami-Wohlert (clover) action. Going to the next order of improvement yields the class of D234 actions. (ii) Anisotropic lattices with at < as useful because they push up the energy of unphysical branches of the dispersion relation (which are generic to highly improved actions), allow accurate mass determinations for particles with bad signal/noise properties (glueballs, P-state mesons), and enable one to simulate heavy quarks within a relativistic framework. We present first simulation results for the quenched light hadron and charmonium spectra obtained with a D234 action on anisotropic lattices.