cssi/SciSciGPT-SciSciNet huggingface dataset:
Dual of a Complete Graph as an Interconnection Network

A new class of interconnection networks, the hypernetworks, has been proposed recently. Hypernetworks are characterized by hypergraphs. Compared with point-to-point networks, they allow for increased resource-sharing and communication bandwidth utilization, and they are especially suitable for optical interconnects. In this paper, we propose a scheme for deriving new hypernetworks using hypergraph duals. As an example, we investigate the dual, K*n, of the n-vertex complete graph Kn and show that it has many desirable properties. We also present a set of fundamental data communication algorithms for K*n. Our results indicate that the K*n hypernetwork is a useful and promising interconnection structure for high-performance parallel and distributed computing systems.
Segmentation of Retail Food Store Formats in Qingdao, China

This study empirically estimates a multivariate binary choice model for four categories of food shopping store formats. The results indicate that in the Qingdao market, traditional counter parts such as wet markets and small grocery stores have been dominated by supermarkets and hypermarkets. At the same time, the rapid growth of hypermarkets in Qingdao is significantly challenging current supermarkets in this city, but they do not compete extensively with wet markets and small grocery stores. Further development of various categories of the food shopping store format is linked to store owned characteristics, potential interrelations among existing retail formats, as well as consumers' demographics and shopping habits.
The complexity of perfect zero-knowledge

A Perfect Zero-Knowledge interactive proof system convinces a verifier that a string is in a language without revealing any additional knowledge in an information-theoretic sense. We show that for any language that has a perfect zero-knowledge proof system, its complement has a short interactive protocol. This result implies that there are not any perfect zero-knowledge protocols for NP-complete languages unless the polynomial time hierarchy collapses. This paper demonstrates that knowledge complexity can be used to show that a language is easy to prove.
A porous-wavemaker theory

A porous-wavemaker theory is developed to analyse small-amplitude surface waves on water of finite depth, produced by horizontal oscillations of a porous vertical plate. Analytical solutions in closed forms are obtained for the surface-wave profile, the hydrodynamic-pressure distribution and the total force on the wavemaker. The influence of the wave-effect parameter C and the porous-effect parameter G, both being dimensionless, on the surface waves and on the hydrodynamic pressures is discussed in detail.
Reaction of zirconium fluoride monohydrate and ammonium bifluoride: its effect on fluoride glass preparation and quality

The products obtained from the room-temperature reaction of ammonium bifluoride and zirconium fluoride monohydrate are ammonium heptafluorozirconate ((NH/sub 4/)/sub 3/ZrF/sub 7/), liquid water, and hydrogen fluoride. This paper discusses ammonium bifluoride and zirconium fluoride monohydrate reacted prior to glass batching, producing dry ammonium heptafluorozirconate which was used to prepare a high-quality ZBLAN fluoride glass.
RETHINKING THE RESOURCE CURSE: Ownership Structure, Institutional Capacity, and Domestic Constraints*

▪ Abstract Most political scientists and economists unequivocally accept the proposition that abundant mineral resources are more often a curse than a blessing, particularly for developing countries. We argue that the widely accepted contention that an abundance of mineral resources and the influx of external rents generated from these resources during boom periods are to blame for the so-called “resource curse” should be revisited. Instead, we offer a new research agenda for studying the problem of resource-rich states that shifts the locus of study away from the “paradox of plenty” to a more appropriate paradox—that the concentration of wealth impoverishes the state whereas the dispersion of wealth enriches the state. This agenda focuses on three interrelated issues: the structure of ownership over mineral resources, the importance of strong institutions, and the relative influence of domestic versus international factors.
OptIPuter--A High Performance SOA LambdaGrid Enabling Scientific Applications

Summary form only given. During the last few years, a radical restructuring of optical networks supporting e-Science projects is beginning to occur around the world. U.S. universities are beginning to acquire access to private, high bandwidth light pipes (termed "lambdas") through the National LambdaRail and the Global Lambda Integrated Facility, providing direct access to global data repositories, scientific instruments, and computational resources from Linux clusters in individual user laboratories. These dedicated connections have a number of significant advantages over shared internet connections, including high bandwidth (10Gbps+), controlled performance (no jitter), lower cost per unit bandwidth, and security. These lambdas enable the Grid program to be completed, in that they add the network elements to the compute and storage elements which can be discovered, reserved, and integrated by the Grid middleware to form global LambdaGrids
A complete solution to the harmonic elimination problem

The problem of eliminating harmonics in a switching converter is considered. That is, given a desired fundamental output voltage, the problem is to find the switching times (angles) that produce the fundamental while not generating specifically chosen harmonics. In contrast to the well known work of Patel and Hoft and others, here all possible solutions to the problem are found. This is done by first converting the transcendental equations that specify the harmonic elimination problem into an equivalent set of polynomial equations. Then, using the mathematical theory of resultants, all solutions to this equivalent problem can be found. In particular, it is shown that there are new solutions that have not been previously reported in the literature. The complete solutions for both unipolar and bipolar switching patterns to eliminate the fifth and seventh harmonics are given. Finally, the unipolar case is again considered where the fifth, seventh, 11th, and 13th harmonics are eliminated along with corroborative experimental results.
Loss and recovery of genetic diversity in adapting populations of HIV

The evolution of drug resistance in HIV occurs by the fixation of specific, well-known, drug-resistance mutations, but the underlying population genetic processes are not well understood. By analyzing within-patient longitudinal sequence data, we make four observations that shed a light on the underlying processes and allow us to infer the short-term effective population size of the viral population in a patient. Our first observation is that the evolution of drug resistance usually occurs by the fixation of one drug-resistance mutation at a time, as opposed to several changes simultaneously. Second, we find that these fixation events are accompanied by a reduction in genetic diversity in the region surrounding the fixed drug-resistance mutation, due to the hitchhiking effect. Third, we observe that the fixation of drug-resistance mutations involves both hard and soft selective sweeps. In a hard sweep, a resistance mutation arises in a single viral particle and drives all linked mutations with it when it spreads in the viral population, which dramatically reduces genetic diversity. On the other hand, in a soft sweep, a resistance mutation occurs multiple times on different genetic backgrounds, and the reduction of diversity is weak. Using the frequency of occurrence of hard and soft sweeps we estimate the effective population size of HIV to be ( confidence interval ). This number is much lower than the actual number of infected cells, but much larger than previous population size estimates based on synonymous diversity. We propose several explanations for the observed discrepancies. Finally, our fourth observation is that genetic diversity at non-synonymous sites recovers to its pre-fixation value within 18 months, whereas diversity at synonymous sites remains depressed after this time period. These results improve our understanding of HIV evolution and have potential implications for treatment strategies.
Experimental Validation of a Four-Way Outphasing Combiner for Microwave Power Amplification

This letter presents a 2.14 GHz, four-way power combining and outphasing system for high-power amplifiers such as those in radio basestations (RBS). The combiner is ideally lossless, and enables power control through load modulation of the power amplifiers (PAs). A discrete-component power combiner is designed and characterized, and combined with inverse Class-F PAs using GaN HEMT devices to develop a complete PA system. We demonstrate the effectiveness of the system over a range of outphasing control angles. This first-ever microwave implementation of the outphasing system has a peak CW drain efficiency of 68.9%, with efficiency greater than 55% over a 5.5 dB power range. It provides an average modulated efficiency of 57% for a W-CDMA signal with 3.47 dB peak to average power ratio (PAPR) at 42 dBm output power.
Computational methods for efficient structural reliability and reliability sensitivity analysis

This paper presents recent developments in efficient structural reliability analysis methods. The paper proposes an efficient, adaptive importance sampling (AIS) method that can be used to compute reliability and reliability sensitivities. The AIS approach uses a sampling density that is proportional to the joint PDF of the random variables. Starting from an initial approximate failure domain, sampling proceeds adaptively and incrementally with the goal of reaching a sampling domain that is slightly greater than the failure domain to minimize over-sampling in the safe region. Several reliability sensitivity coefficients are proposed that can be computed directly and easily from the above AIS-based failure points. These probability sensitivities can be used for identifying key random variables and for adjusting design to achieve reliability-based objectives. The proposed AIS methodology is demonstrated using a turbine blade reliability analysis problem.
Language, Agglomeration and Hispanic Homeownership

As of the fourth quarter of 2007, 74.9% of white non-Hispanic families but only 48.5% of Hispanic families owned homes. We argue that low rates of homeownership in Hispanic communities create a self-reinforcing mechanism that contributes to this large disparity. In part, this occurs because proximity to other homeowners belonging to a family's social network improves access to information about how to become a homeowner. Role model effects may also be relevant. We investigate these issues using household-level data on out-of-state movers from the 2000 Decennial Census. Three especially important results are obtained. First, proximity to Hispanic homeowners in the 1995 place of residence increases the propensity of a Hispanic family to own a home in 2000. Second, that effect is especially strong with respect to proximity to weak English-speaking Hispanic homeowners. Third, these patterns hold regardless of the Hispanic family's own ability to speak English. From a policy perspective, these results suggest that local programs designed to promote homeownership among weak English-speaking Hispanic families likely increase Hispanic homeownership beyond just the immediate program participants.
An Exploratory Study of Silylated Amino Boronic Ester Chemistry

Diisopropyl [bis(trimethylsilylamino)methyl]-boronate, the analogous pinacol boronic ester (3), andpinacol [(2,2,5,5-tetramethyl-2,5,1-disilazol-1-yl)-methyl]boronate (8) were prepared from the corresponding (bromomethyl)boronic ester 1 or 2 and silylated lithium amide. Reaction of 3 or 8 with (dichloromethyl)lithium yielded the corresponding [1-chloro-2-(silylated amino)ethyl]boronate 4 or 9. Further transformations of 4 to methylthio derivative 5 and dimethylamino derivative 7 as well as conversion of 5 to ureido derivatives 6 are described. (S,S)-1,2-Dicyclohexylethanediol [1-chloro-2-(trityloxy)-ethyl]boronate (13) has been converted to bis(tri-methylsilyl)amino derivative 14 and formamido derivative 15 as well as to N-benzyl analogs 18 and 19. Attempted chain extensions of 14, silylated 15, or 19 with (dichloromethyl)lithium indicated that the alkyl migration from boron to carbon is slow and incomplete. © 1997 John Wiley & Sons, Inc. Heteroatom Chem 8:487–494, 1997
The State of American Federalism 2007–2008: Resurgent State Influence in the National Policy Process and Continued State Policy Innovation

States played a prominent role in policy-making in 2007-2008 in several respects. States were more successful in securing relief from federal directives regarding the National Guard, homeland security, education, and welfare than in any prior year in the Bush presidency; they were unable to fend off several new mandates, however, particularly concerning the State Children's Health Insurance Program. States also continued to be the primary innovators in areas such as immigration, environmental protection, and health care, although they encountered new constraints in the form of federal court challenges and agency rulings. The Supreme Court made no notable contributions to the post-1992 decisions that initially curbed and recently deferred to federal power; however, several rulings interpreting federal statutes and reviewing state acts had important federalism implications.
QUADRATIC SERENDIPITY FINITE ELEMENTS ON POLYGONS USING GENERALIZED BARYCENTRIC COORDINATES.

We introduce a nite element construction for use on the class of convex, planar polygons and show it obtains a quadratic error convergence estimate. On a convex n-gon satisfying simple geometric criteria, our construction produces 2n basis functions, associated in a Lagrange-like fashion to each vertex and each edge midpoint, by transforming and combining a set of n(n + 1)=2 basis functions known to obtain quadratic convergence. The technique broadens the scope of the so-called ‘serendipity’ elements, previously studied only for quadrilateral and regular hexahedral meshes, by employing the theory of generalized barycentric coordinates. Uniform a priori error estimates are established over the class of convex quadrilaterals with bounded aspect ratio as well as over the class of generic convex planar polygons satisfying additional shape regularity conditions to exclude large interior angles and short edges. Numerical evidence is provided on a trapezoidal quadrilateral mesh, previously not amenable to serendipity constructions, and applications to adaptive meshing are discussed.
Regional patterns of U.S. household carbon emissions

Market-based policies to address fossil fuel-related externalities including climate change typically operate by raising the price of those fuels. Increases in energy prices have important consequences for a typical U.S. household that spent almost $4,000 per year on electricity, fuel oil, natural gas, and gasoline in 2005. A key question for policymakers is how these consequences vary over different regions and subpopulations across the country—especially as adjustment and compensation programs are designed to protect more vulnerable regions. To answer this question, we use non-publicly available data from the U.S. Consumer Expenditure Survey over the period 1984–2000 to estimate long-run geographic variation in household use of electricity, fuel oil, natural gas, and gasoline, as well as the associated incidence of a $10 per ton tax on carbon dioxide (ignoring behavioral response). We find substantial variation: incidence from the tax range from $97 dollars per year per household in New York County, New York to $235 per year per household in Tensas Parish, Louisiana. This variation can be explained by differences in energy use, carbon intensity of electricity generation, and electricity regulation.
An Economic Model of Fair Use

The doctrine of fair use allows limited copying of creative works based on the rationale that copyright holders would consent to such uses if bargaining were possible. This paper develops a formal model of fair use in an effort to derive the efficient legal standard for applying the doctrine. The model interprets copies and originals as differentiated products and defines fair use as a threshold separating permissible copying from infringement. The analysis highlights the role of technology in shaping the efficient standard. Discussion of several key cases illustrates the applicability of the model.
A Recovery Algorithm of Linear Complexity in the Time-Domain Layered Finite Element Reduction Recovery (LAFE-RR) Method for Large-Scale Electromagnetic Analysis of High-Speed ICs

Time-domain layered finite element reduction recovery (LAFE-RR) method was recently developed for large-scale electromagnetic analysis of high-speed integrated circuits (ICs). This method is capable of analytically and rigorously reducing the system matrix of a 3-D multilayer circuit to that of a single-layer one regardless of the original problem size. In addition, the reduced system matrix preserves the sparsity of the original system matrix. In this paper, an efficient algorithm is proposed to recover the volume unknowns in the time-domain LAFE-RR method. This algorithm constitutes a direct solution of the matrix formed by volume unknowns in each layer. This direct solution possesses a linear complexity in both central processing unit (CPU) time and memory consumption. The cost of matrix inversion is negligible. The cost of matrix solution scales linearly with the matrix size. Numerical and experimental results have demonstrated the accuracy and efficiency of the proposed algorithm.
Optimizing precision overhead for x86 processors

It is a major challenge for a Java JIT compiler to perform single-precision floating-point operations efficiently for the x86 processors. In previous research, the double-precision mode is set as the default precision mode when methods are invoked. Sophisticated approaches then use heuristic approaches to optimization by considering the trade-offs between roundings and mode switches. However, this convention introduces redundant mode switches across method boundaries. Furthermore, methods that include both single- and double-precision operations cannot switch the mode, even if single-precision operations are dominant. We propose a new approach to these problems. We eliminate redundant mode switches by ignoring the default precision mode and calling a method in the same precision mode as the caller. For methods that include both single- and double-precision methods, we reduce the overhead of rounding by isolating code segments of a given method that should be executed in the single-precision mode. We implemented our approach in IBM's Just-in-Time compiler, and obtained experimental results demonstrating that, in SPECjvm98, it consistently shows the best performance in any configuration of benchmark programs, inline policies, and processor architectures compared with previous research approaches. Copyright © 2004 John Wiley & Sons, Ltd.
Advances in the Catalytic, Asymmetric Synthesis of β-Lactams

In this Account, we illustrate our contribution to the catalytic, asymmetric synthesis of β-lactams through a flexible [2 + 2] cycloaddition strategy. We also explore the scope of our methodology and comment on future directions.
Accurate Subgrid Models for Two-Phase Flow in Heterogeneous Reservoirs

Subgrid effects can have a strong influence on flow and transport in oil reservoirs. In this work, a new model for the representation of subgrid terms is introduced and applied to two-phase reservoir flows. The model entails a generalized convection-diffusion treatment of the saturation equation as well as an extended representation for total mobility in the pressure equation. Motivation for the form of the model is provided through a consideration of volume averaging and homogenization results. The numerical computation of the subgrid terms and the implementation of the overall method are described. The accuracy of the new subgrid representation is compared to that of coarse-scale models with no subgrid treatment and to coarse models based on pseudorelative permeabilities. The new model consistently provides more accurate overall coarsescale predictions, relative to reference fine-scale results, than the other coarse-scale models, particularly in cases when the global boundary conditions vary in time.
The curious case of Confession Bear: the reappropriation of online macro-image memes

‘Advice animals’ are popular user-created, image-based, and online meme formats. The memes include a humorous image of an animal juxtaposed with text offering advice and/or making a joke. One such example is known as ‘Confession Bear’, which features a sad looking Malayan sun bear ‘confessing’ to something silly, shameful, taboo, or embarrassing. Confession Bear was first circulated through the online community Reddit and was intended to be humorous. However, users unexpectedly started creating and sharing more serious confessions involving topics such as rape, abuse, and addiction. These more serious confessions juxtaposed with the Confession Bear image spurred lengthy in-depth conversations on the Reddit message boards about the validity, authenticity, and appropriateness of such confessions. Some users argued advice animals were not ‘supposed’ to be serious, claiming these confessions were an inappropriate use of the form; as such, some users attempted to regulate the participatory culture created by t...
Carbon Ignition in Type Ia Supernovae. II. A Three-dimensional Numerical Model

The thermonuclear runaway that culminates in the explosion of a Chandrasekhar mass white dwarf as a Type Ia supernova begins centuries before the star actually explodes. Here, using a three-dimensional anelastic code, we examine numerically the convective flow during the last minute of that runaway, a time that is crucial in determining just where and how often the supernova ignites. We find that the overall convective flow is dipolar, with the higher temperature fluctuations in an outbound flow preferentially on one side of the star. Taken at face value, this suggests an asymmetric ignition that may well persist in the geometry of the final explosion. However, we also find that even a moderate amount of rotation tends to fracture this dipole flow, making ignition over a broader region more likely. Although our calculations lack the resolution to study the flow at astrophysically relevant Rayleigh numbers, we also speculate that the observed dipolar flow would become less organized as the viscosity becomes very small. Motion within the dipole flow shows evidence of turbulence, suggesting that only geometrically large fluctuations (~1 km) would persist to ignite the runaway. We also examine the probability density function for the temperature fluctuations, finding evidence for a Gaussian rather than exponential distribution, which suggests that ignition sparks may be strongly spatially clustered.
Asymmetric synthesis of chiral cycloalkenone derivatives via palladium catalysis

The palladium-catalyzed oxidative desymmetrization of meso-dibenzoates yields γ-benzoyloxy cycloalkenones in good yields and with excellent levels of enantioselectivity. These compounds serve as precursors to a broad range of substituted cycloalkenones, including well-established synthetic building blocks and elaborated cycloalkanone derivatives. The ability to prepare both enantiomers of the oxidative desymmetrization products enables a unified strategy toward stereochemically diverse epoxyquinoid natural products.
Complementarity, Integration, and Responsiveness: Making E-Government Work in Developing Nations

This is a review of: Nagy K. Hanna, Transforming Government and Building the Information Society: Challenges and Opportunities for the Developing World (New York: Springer, 2010).
Value-function approximations for partially observable Markov decision processes

Partially observable Markov decision processes (POMDPs) provide an elegant mathematical framework for modeling complex decision and planning problems in stochastic domains in which states of the system are observable only indirectly, via a set of imperfect or noisy observations. The modeling advantage of POMDPs, however, comes at a price -- exact methods for solving them are computationally very expensive and thus applicable in practice only to very simple problems. We focus on efficient approximation (heuristic) methods that attempt to alleviate the computational problem and trade off accuracy for speed. We have two objectives here. First, we survey various approximation methods, analyze their properties and relations and provide some new insights into their differences. Second, we present a number of new approximation methods and novel refinements of existing techniques. The theoretical results are supported by experiments on a problem from the agent navigation domain.
On the classification of 6D SCFTs and generalized ADE orbifolds

We study (1; 0) and (2; 0) 6D superconformal eld theories (SCFTs) that can be constructed in F-theory. Quite surprisingly, all of them involve an orbifold singularity C 2 = with a discrete subgroup of U(2). When is a subgroup of SU(2), all discrete subgroups are allowed, and this leads to the familiar ADE classication of (2 ; 0) SCFTs. For more general U(2) subgroups, the allowed possibilities for are not arbitrary and are given by certain generalizations of the A- and D-series. These theories should be viewed as the minimal 6D SCFTs. We obtain all other SCFTs by bringing in a number of E-string theories and/or decorating curves in the base by non-minimal gauge algebras. In this way we obtain a vast number of new 6D SCFTs, and we conjecture that our construction provides a full list.
Predicate Privacy in Encryption Systems

Predicate encryption is a new encryption paradigm which gives a master secret key owner fine-grained control over access to encrypted data. The master secret key owner can generate secret key tokens corresponding to predicates. An encryption of data x can be evaluated using a secret token corresponding to a predicate f ; the user learns whether the data satisfies the predicate, i.e., whether f (x ) = 1. Prior work on public-key predicate encryption has focused on the notion of data or plaintext privacy, the property that ciphertexts reveal no information about the encrypted data to an attacker other than what is inherently revealed by the tokens the attacker possesses. In this paper, we consider a new notion called predicate privacy , the property that tokens reveal no information about the encoded query predicate. Predicate privacy is inherently impossible to achieve in the public-key setting and has therefore received little attention in prior work. In this work, we consider predicate encryption in the symmetric-key setting and present a symmetric-key predicate encryption scheme which supports inner product queries. We prove that our scheme achieves both plaintext privacy and predicate privacy.
The Fas System is a Key Regulator of Germ Cell Apoptosis in the Testis

Apoptosis occurs in the testis as an important physiological mechanism to limit the number of germ cells in the seminiferous epithelium. Sertoli cells, which tightly regulate germ cell proliferation and differentiation, are implicated in the control of germ cell apoptosis. Fas (APO-1, CD95), a transmembrane receptor protein, transmits an apoptotic signal within cells when bound by Fas ligand (FasL). The Fas system has been implicated in immune regulation, including cytotoxic T cell-mediated cytotoxicity, activation-induced suicide of T cells, and control of immune-privileged sites. Here we propose the Fas system as a key regulator of spermatogenesis. In this model, FasL expressed by Sertoli cells initiates the apoptotic death of germ cells expressing Fas. Using immunohistochemistry, we localized Fas to germ cells and FasL to Sertoli cells. The expression of these genes was dramatically up-regulated after exposure to mono-(2-ethylhexyl) phthalate and 2,5-hexanedione, two widely studied Sertoli cell toxicants known to induce germ cell apoptosis. Mouse germ cells in vitro were susceptible to anti-Fas antibody-induced death, and the survival of rat germ cells was increased after disruption of FasL by antisense oligonucleotide treatment. Unlike its expression in other tissues, testicular expression of Fas in the lpr mouse, a spontaneous mutant of the Fas gene, is similar to that in the normal mouse, arguing for the importance of the Fas system in maintaining testicular homeostasis. These data implicate the Sertoli cell in the paracrine control of germ cell output during spermatogenesis by a Fas-mediated pathway.
The effects of welfare and tax reform: the material well-being of single mothers in the 1980s and 1990s

Abstract The tax and welfare programs that provide income and in-kind benefits to single mothers have changed dramatically in recent years. These changes began as far back as the mid-1980s and culminated with the 1996 welfare law that ‘ended welfare as we knew it.’ These tax and welfare changes have sharply increased the employment of single mothers and cut welfare rolls. However, little is know about the effects of these policy changes on the material well-being of single mothers and their children. Studies of those leaving welfare have found that a substantial percentage have problems paying rent, purchasing enough food, and paying utility bills. Other studies found a decline in income among the worst-off single mothers after 1994 or 1995. The goal of this paper is to examine the material well-being of single mothers and their families before and after recent welfare and tax reforms. Using data from two nationally representative household surveys we examine the consumption patterns of single mothers and their families from 1984–2000. We find that the material conditions of single mothers did not decline in recent years, either in absolute terms or relative to single childless women or married mothers. This pattern holds for the average single mother as well as for low-educated single mothers at both the 15th and 25th percentiles of the consumption distribution. In most cases, our evidence suggests that the material conditions of single mothers have improved slightly.
Liouvillian Solutions of Linear Differential Equations with Liouvillian Coefficients

Let L(y) = b be a linear differential equation with coefficients in a differential field K. We discuss the problem of deciding if such an equation has a non-zero solution in K and give a decision procedure in case K is an elementary extension of the field of rational functions or is an algebraic extension of a transcendental liouvillian extension of the field of rational functions. We show how one can use this result to give a procedure to find a basis for the space of solutions, liouvillian over K, of L(y) = 0 where K is such a field and L(y) has coefficients in K.
Cluster Magnetic Fields

▪ Abstract Magnetic fields in the intercluster medium have been measured using a variety of techniques, including studies of synchrotron relic and halo radio sources within clusters, studies of inv...
Selective lithiation of 2,3-dibromo-1-methylindole. A synthesis of 2,3-disubstituted indoles

Abstract Indole ( 1 ) can be converted to 2,3-dibromo-1-methylindole ( 3 ) in two operations (92% yield). Treatment of 3 with tert -butyllithium effects clean monolithiation to 3-bromo-2-lithio-1-methylindole ( 4 ), which can be trapped with various electrophiles to afford the 3-bromo-2-substituted indoles ( 5 – 8 ) in 85–99% yield. A second bromine–lithium exchange reaction and quenching with electrophiles yields the 2,3-disubstituted indoles ( 9 – 10 ) in 88–95% yield.
Meso-Substituted [34]Octaphyrin(1.1.1.0.1.1.1.0) and Corrole Formation in Reactions of a Dipyrromethanedicarbinol with 2,2‘-Bipyrrole

The reaction of a dipyrromethanedicarbinol with 2,2'-bipyrrole leading to meso-substituted [34]octaphyrin(1.1.1.0.1.1.1.0) and/or corrole was investigated to determine the effect of key reaction parameters on the distribution of the two macrocycles. Solvent, acid catalyst, acid quantity, oxidant, oxidant quantity, and reaction time were surveyed for a model reaction affording 5,10,19,24,29,38-hexaphenyl[34]octaphyrin(1.1.1.0.1.1.1.0) (HPO) and/or meso-triphenylcorrole (TPC). HPO was found to be a fairly ubiquitous product, produced in yields as high as 23% (UV-vis), while TPC was observed infrequently, in yields up to 10% (UV-vis). A preparative-scale reaction provided HPO in an isolated yield of 25%. The methodology was extended to the synthesis of an octaphyrin bearing two different substituents in defined locations and to an octaphyrin possessing electron-withdrawing pentafluorophenyl substituents. Preferential formation of octaphyrin instead of corrole suggests that the anti conformation of 2,2'-bipyrrole is the relevant form under the reaction conditions surveyed. The spectral properties of the novel meso-substituted [34]octaphyrin(1.1.1.0.1.1.1.0) species are similar to those of the known beta-substituted analogue, including spectra consistent with the absence of macrocycle aromaticity despite a main conjugation path of 34 pi-electrons. Key to the overall study was the development of a refined synthesis of 2,2'-bipyrrole.
The perils of debt deflation in the Euro area: a multi regime model

Academic research and policy makers in the Euro area are currently concerned with the threat of debt deflation and secular stagnation in Europe. Empirical evidence seems to suggest that secular stagnation and debt deflation in the Euro area may be rather slowly developing. Yet what appears as major peril is that debt deflation with a lack of economic growth, rising real interest rates and further rising debt may trigger household defaults, defaults of firms and banks, rise of risk premia, and default risk of certain sectors of the economy or sovereign defaults. It is this rising default and financial risk then that may lead to a regime change to a slowly moving debt crisis with high financial risk and high financial stress. In order to explore those issues, a macro policy model of Svensson type is introduced, exhibiting a regime of low and high financial stress. Then, a four dimensional multi-regime VAR is employed to an Euro area data set to support the theoretical model and the claim that in particular Southern Euro area countries are affected by debt deflation and financial market stress.
Elastic Instability of the Orthorhombic Antiferromagnetic Phase of 122-Pnictides Under Pressure

A-122 pnictides (A an alkaline earth element) possess striped antiferromagnetic states of orthorhombic (OR) symmetry and nonmagnetic states of tetragonal (T) symmetry. Based on total energy calculations, we show that the T = 0 K pressure-driven transition from OR to T states occurs at a pressure, PH, where the tetragonal enthalpy drops below the orthorhombic. The OR state remains metastable up to a higher pressure, PM > PH. We find anomalies in magnetism and orthorhombicity as P → PM and a trend towards elastic instability.
Back to the Basics: In Defense of Achievement (and Achievement Tests) in College Admissions

Summarizing a decade of research at the University of California, this paper concludes that admissions criteria that tap student mastery of curriculum content, such as high-school grades and performance on achievement tests, are stronger predictors of success in college and are fairer to
Economic Incentives and the Defense Procurement Process

This paper describes some of the insights that the economic theory of incentives can contribute to defense procurement policy analysis. It describes the underlying incentive problems that shape the defense procurement problem, the nature of current institutions and how they affect actors' behavior, and possible directions for improving the procurement process suggested by viewing it as a solution to a complex set of incentive problems. Incentive problems between government and defense firms and incentive problems within government are both considered.
Restoring Pure Equilibria to Weighted Congestion Games

Congestion games model several interesting applications, including routing and network formation games, and also possess attractive theoretical properties, including the existence of and convergence of natural dynamics to a pure Nash equilibrium. Weighted variants of congestion games that rely on sharing costs proportional to players' weights do not generally have pure-strategy Nash equilibria. We propose a new way of assigning costs to players with weights in congestion games that recovers the important properties of the unweighted model. This method is derived from the Shapley value, and it always induces a game with a (weighted) potential function. For the special cases of weighted network cost-sharing and weighted routing games with Shapley value-based cost shares, we prove tight bounds on the worst-case inefficiency of equilibria. For weighted network cost-sharing games, we precisely calculate the price of stability for any given player weight vector, while for weighted routing games, we precisely calculate the price of anarchy, as a parameter of the set of allowable cost functions.
Using cadaver simulation to improve communication and economy of movement as evidence of progress with the trans-catheter aortic valve implantation (TAVI) learning curve

Trans-catheter Aortic Valve Implantation (TAVI) is an endovascular treatment for critical aortic stenosis. An early "learning curve" is important drawback of TAVI that can dramatically alter patient safety and hospital costs. There is paucity of data regarding the quantification of learning experience associated with the technique. The aim of this study was to assess learning curve in clinical staff involved in the implementation of TAVI. We hypothesize that training sessions will improve economy of movement (EoM) as characterized by measuring jerkiness of trunk movement in medial-lateral direction. Using wearable technology based on tri-axial accelerometer, the EoM of a scrub technician, who was naive to TAVI procedure, was assessed during 6 consecutive TAVI procedures, including 4 cadaver TAVI simulations and 2 clinical cases. In addition, communication errors between the surgery team were monitored. During the cadaver simulation training, the communication error was reduced by 46.2%. Similarly, the EoM was enhanced by 17.3% (p=0.04) with a non-significant reduction rate of 4.99±4.26% per practice. Interestingly, both communication errors and EoM were reduced during real cases compared to the first simulated case, suggesting that cadaver simulation translated into real cases. This proof of concept study suggests that EoM could be used as an alternative method to objectively evaluate the learning curve during surgical procedures. Results should be confirmed in a larger sample size in both physicians and support staff assisting with TAVI procedure.
Topological electronic structure in half-Heusler topological insulators

We have investigated band structures of a series of 28 ternary half-Heusler compounds $M{M}^{\ensuremath{'}}X$ of MgAgAs type, where $M=(\text{Lu},\text{La},\text{Sc},\text{Y})$ and ${M}^{\ensuremath{'}}X=(\text{PtBi},\text{AuPb},\text{PdBi},\text{PtSb},\text{AuSn},\text{NiBi},\text{PdSb})$. Our results show that the ${Z}_{2}$ topological order is due to a single band inversion at the $\ensuremath{\Gamma}$ point. In native states, these half-Heusler compounds are identified as being topologically nontrivial semimetals, or nontrivial metals, or trivial insulators, which can be turned into insulating thin films on suitable substrates. Our analysis reveals a straightforward relationship which connects the band inversion strength (extent of deviation from the critical point) to the atomic charge of constituents and the lattice parameter. Our findings suggest a general method for identifying ${Z}_{2}$ topological insulators in nonmagnetic ternary compounds.
Stability and scalability of piezoelectric flags

We investigate the effect of piezoelectric material on the flutter speed, vibration mode and frequency, and energy harvesting power and efficiency of a flexible flag in various fluids. We develop a fully coupled fluid-solid-electric model by combining the inviscid vortex sheet model with a linear electro-mechanical coupling model. A resistance only circuit and a resonant resistance-inductance (RL) circuit are considered. For a purely resistive circuit, an increased electro-mechanical coupling factor results in an increased flutter speed, vibration frequency, averaged electric power, and efficiency. A consistent optimal resistance is found that maximizes the flutter speed and the energy harvesting power. For a resonant RL circuit, by tuning the inductance to match the circuit frequency to the flag’s vibration frequency, the flutter speed can be greatly decreased, and a larger averaged power and efficiency are obtained. We also consider a model scale setup with several commonly used commercial materials for...
Copula Methods for Forecasting Multivariate Time Series

Abstract Copula-based models provide a great deal of flexibility in modeling multivariate distributions, allowing the researcher to specify the models for the marginal distributions separately from the dependence structure (copula) that links them to form a joint distribution. In addition to flexibility, this often also facilitates estimation of the model in stages, reducing the computational burden. This chapter reviews the growing literature on copula-based models for economic and financial time series data, and discusses in detail methods for estimation, inference, goodness-of-fit testing, and model selection that are useful when working with these models. A representative data set of two daily equity index returns is used to illustrate all of the main results.
Considering Student Voices: Examining the Experiences of Underrepresented Students in Intervention Programs

Qualitative studies that examine the experiences of underrepresented minority students in science, technology, engineering, and mathematics fields are comparatively few. This study explores the self-reported experiences of underrepresented graduate students in the biomedical sciences of a large, midwestern, urban university. Document analysis of interview transcripts from program evaluations capture firsthand accounts of student experiences and reveal the need for a critical examination of current intervention programs designed to reverse the trend of underrepresentation in the biomedical sciences. Findings point to themes aligned around the benefits and challenges of program components, issues of social adjustment, the utility of supportive relationships, and environmental impacts.
Synthesis of Bis‐1,2,4‐triazines via Telescoped Condensation of [1,10]‐Phenanthroline‐2,9‐dicarbonitrile with Aromatic 1,2‐Dicarbonyls

Efficient separation of minor actinides from spent nuclear fuel remains a formidable challenge. As part of ongoing efforts to identify effective ligands for separation of toxic radionuclides, a series of bis-1,2,4-triazines, three novel, have been prepared from [1,10]-phenanthroline-2,9-dicarbonitrile in two-telescoped steps without additives, complicated workups, prolonged reaction times, or additional purification.
Linking Risk Models to Microeconomic Indicators

Catastrophe risk models are quantitative models used to estimate probabilistic loss distributions for a specified range of assets subject to a baseline level of disaster risk. While cat risk models are used extensively by the insurance and reinsurance industry to estimate expected losses to insured assets, their ability to estimate damages outside of a narrow range of physical assets such as buildings or infrastructure is still limited. This paper first provides a brief outline of cat risk models as they currently exist, and then outlines the major econometric issues involved in incorporating research from the growing literature on the microeconomic impacts of disasters into a cat model framework. Attention is specifically drawn to issues arising from the generally low recurrence frequencies of disasters, the likely role of difficult-to-document indirect damages in influencing total disaster costs, and issues related to generalizing disaster response functions across different domains. The paper ends by noting the large discrepancy between the current state of the literature on disaster impacts on microeconomic indicators and the level needed for adequate cat risk model performance, and suggests means of closing that gap as well as potential areas for future research.
Kagomé lattices as cathode: Effect of particle size and fluoride substitution on electrochemical lithium insertion in sodium- and ammonium Jarosites

Abstract Highly crystalline sodium and ammonium Jarosites, NaFe3(SO4)2(OH)6 and NH4Fe3(SO4)2(OH)6, have been synthesized employing hydrothermal synthesis routes. The structures consist of anionic layers of vertex-sharing FeO6 octahedra and SO4 tetrahedral units with interlayer space occupied by Na and ammonium ions, respectively. The corner-sharing FeO6 octahedral units form six and three rings similar to hexagonal tungsten bronze sheets also known as kagome lattice. These sodium and ammonium Jarosites are thermally stable up to 400 °C and undergo facile electrochemical lithium insertion through the reduction of Fe3+ to Fe2+. Galvanostatic charge–discharge indicates that up to 2.25 and 2 lithium ions per formula unit can be inserted at an average voltage of 2.49 and 2.26 V to the sodium and the ammonium Jarosites, respectively, under slow discharge rate of C/50. The cycle-life and experimental achievable capacity show strong dependence on particle sizes and synthesis conditions. A small amount of fluoride substitution improves both achievable capacity and average voltage.
Carlstrom and Fuerst meets Epstein and Zin: The Asset Pricing Implications of Contracting Frictions

Models with financial frictions have been shown to create amplification and persistence effects in macroeconomic fluctuations. We test the ability that Costly State Verification (CSV) has to generate empirically plausible risk exposures in asset markets, when Epstein and Zin (1989) preferences are implemented. Under the setup of Carlstrom and Fuerst (1997) alongside recursive preferences, we find that the CSV friction is negligible in augmenting the aggregate equity premium, explaining roughly thirty basis points when monitoring costs are increased. Additionally we find that the separation between the elasticity of intertemporal substitution and risk aversion plays a key role in explaining financial market dynamics. We are only able to generate sizable equity premium when the elasticity is greater than one.
Suppression of collisionless magnetic reconnection in asymmetric current sheets

Using fully kinetic simulations, we study the suppression of asymmetric reconnection in the limit where the diamagnetic drift speed ≫ Alfven speed and the magnetic shear angle is moderate. We demonstrate that the slippage between electrons and the magnetic flux mitigates the suppression and can even result in fast reconnection that lacks one of the outflow jets. Through comparing a case where the diamagnetic drift is supported by the temperature gradient with a companion case that has a density gradient instead, we identify a robust suppression mechanism. The drift of the x-line is slowed down locally by the asymmetric nature of the x-line, and then the x-line is run over and swallowed by the faster-moving following flux.