cssi/SciSciGPT-SciSciNet huggingface dataset:
On linear electromagnetic constitutive laws that define almost-complex structures

It is shown that not all linear electromagnetic constitutive laws will define almost-complex structures on the bundle of 2-forms on the spacetime manifold when composed with the Poincare duality isomorphism, but only a restricted class of them that includes linear spatially isotropic and some bi-isotropic constitutive laws. Although this result does not trivialize the formulation of the basic equations of pre-metric electromagnetism, it does affect their reduction to metric electromagnetism by its effect on the types of media that are reducible, and possibly its effect on the way that such media support the propagation of electromagnetic waves.
SDVS: a system for verifying microcode correctness

This paper is a progress report on an experimental system, the state delta verification system (SDVS), for verifying microcode correctness. The goal of this project is to solve some of the problems, both theoretical and engineering, obstructing the realization of a usable and applicable program for checking proofs of microcode correctness. The ideal result would be a system that could be naturally incorporated into the specification-implementation cycle of, for example, microcoded machine instruction sets.
Surface composition of fluorinated poly(amide urethane) block copolymers by electron spectroscopy for chemical analysis

Abstract : The surface composition and near surface depth profiles of solution-cast films of poly(amide urethane) block copolymers were measured using angle-dependent electron spectroscopy for chemical analysis (ESCA). Segregation of fluorinated polyamide soft segment to the surface was detected and quantified. The poly(amide urethane)s were made from amine-terminated polyamides with N-alkylated fluorinated side chains as well as fluorinated backbones, methylenebis(cyclohexane diisocyanate) H12MDI, and butanediol. The resulting copolymers display extremely low surface energy. Annealing of the solution-cast films drives the fluorinated side chains to the surface. A deconvolution program was utilized to obtain composition depth profiles and to confirm phase segregation. (AN)
A nonenzymatic acid/peracid catalytic cycle for the Baeyer-Villiger oxidation.

The combined action of carbodiimide and hydrogen peroxide upon exposure to carboxylic acid catalysts serves to generate transient peracids that can be engaged in the Baeyer−Villiger rearrangement of ketones to lactones. Up to 35 turnovers of the catalytic cycle may be achieved. The conditions are especially useful in the context of reactive cyclohexanones, and allow the use of H2O2 as the terminal oxidant. A singular example of a chiral catalyst demonstrates, in principle, that enantioselective catalysis will be possible with this strategy for catalyst turnover.
Observations from a prototype implementation of the common APSE interface set (CAIS)

This paper presents an overview of the Common Ada Programming Support Environment (APSE) Interface Set (CAIS), its purpose, and its history. The paper describes an internal research and development effort at the Mitre Corporation to implement a prototype version of the current CAIS specification and to rehost existing Ada software development tools onto the CAIS prototype. Based on this effort, observations are made on the maturity and functionality of the CAIS. These observations support the government's current policy of publicizing the CAIS specification as a baseline for public review in support of its evolution into a standard which can be mandated for use as Ada is today.
On the Absolutely Continuous Spectrum of Dirac Operator

We prove that the massless Dirac operator in ℝ3 with long-range potential has an a.c. spectrum which fills the whole real line. The Dirac operators with matrix-valued potentials are considered as well.
Liquid–Metal Vertical Interconnects for Flip Chip Assembly of GaAs C-Band Power Amplifiers Onto Micro-Rectangular Coaxial Transmission Lines

Prior work has demonstrated a new process utilizing room-temperature liquid metal, Galinstan, as an interconnect material for flip-chip bonding. This interconnect forms a flexible bond between chips and carriers, and, therefore, a flip-chip assembly using this technology is much less susceptible to thermomechanical stresses. This paper applies this concept to interconnect GaAs MMIC chips to 3-D Polystrata transmission-line structures. Passive assemblies are utilized to model, test, and verify liquid-metal interconnections, giving average losses per liquid-metal transition of about 0.11 dB out to 26.5 GHz, low parasitics per transition, and demonstrated reliability after temperature cycling. A prefabricated GaAs MMIC chip is postprocessed for liquid-metal assembly. Measured results show, over the MMIC's 4.9-8.5-GHz frequency range, the system's overall reduction in gain of the MMIC is 1.4 dB or 0.7 dB per RF transition as compared with direct probing of the MMIC chip.
Synthesis, 1H‐ and 13C‐NMR spectra, crystal structure and ring openings of 1‐methyl‐6,9‐epoxy‐9‐aryl‐5,6,9,10‐tetrahydro‐1H‐imidazo [3,2‐e] [2H‐1,5] oxazocinium methanesulfonate

The methanesulfonic acid catalyzed reaction of 1-(4-chloro- and 2,4-dichlorophenyl)-2-(1-methyl-2-imida-zolyl)ethanones 1a and 1b with glycerol produced cis- and trans-{2-haloaryl-2-[(1-methyl-2-imidazolyl)methyl]-4-hydroxymethyl}-1,3-dioxolanes 2a and 2b with a 2:1 cis/trans ratio. Besides these five-membered ketals, the reaction of 1a with glycerol afforded a small amount of trans-{2-(4-chlorophenyl)-2-[(1-methyl-2-imidazolyl)methyl]-5-hydroxy}-1,3-dioxane (3a, 7%). The reaction of methanesulfonyl chloride with cis-1 formed the corresponding methanesulfonates, cis-4, which rapidly cyclized to the title compounds 5. Base-catalyzed ring opening of 5 furnished 1-methyl-5,6-dihydro-6-hydroxymethyl-8-(4-chloro- and 2,4-dichlorophenyl)-1H-imidazo[3,2-d][1,4]oxazepinium methanesulfonates 7. Acid-catalyzed hydrolyses of 5 or 7 provided 1-methyl-2-[(4-chloro- and 2,4-dichloro)phenacyl]-3-[(2,3-dihydroxy)-1-propyl]imidazolium salts 12. Structure proofs were based on extensive 1H and 13C chemical shifts and coupling constants and structures of 3a and 5a were confirmed by single crystal X-ray crystallography.
Thermal analysis and design of polarizer mirrors for waveguides in the DIII-D tokamak

A new high power electron cyclotron heating (ECH) system designed to operate at 110 GHz with a power output of 2 MW has been introduced on DIII-D. All components of the system are capable of handling a 10 second pulse at an interval of 10 minutes. Transmission of ECH power from the source (a millimeter-wave gyrotron) to the plasma through waveguide miter bends may change the polarization and rotate the polarization major axis. Polarizing elements are therefore required to correct for the effect of transmission lines and also to generate proper polarization for coupling into the plasma. Rotating mirrors with different rectangular grooved gratings in two successive miter bends can generate the required wide range of elliptical polarizations. Peak heat fluxes due to ohmic losses in these mirrors are several MW/m2 for a 0.5 MW gyrotron power. The complex distribution of losses in the grooves requires a detailed thermal stress analysis to ensure that temperature and stress limits are not exceeded. The desired pulse length is 10 sec, with a cooling time of 10 min between pulses. The temperature rise in the polarizing mirrors must be limited to less than 300 degree(s)C to prevent thermal fatigue and outgassing in the vacuum lines. This paper presents an analysis for the polarizing mirrors for the DIII-D ECH system.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Chiral N-heterocyclic carbene-transition metal complexes in asymmetric catalysis

Syntheses and applications of chiral N-heterocyclic carbenes are reviewed. The common features of successful enantioselective catalysts are identified, and the outlook for further investigations is discussed.
The Direct Diels-Alder Synthesis of Derivatives of 7-Oxo-5-Norbornene-2-Carboxylic Acid

Abstract The synthesis of 7,7-di-(1′-propyloxy)-5-norbornene-2-carbonitrile and the corresponding ethyl ester by direct Diels-Alder methods is described. The synthesis of 5,5-di-(1′-propoxy)-1,3-cyclopentadiene affords practical advantages over the diethyl and dimethyl analogs which make it simpler to prepare.
Synthesis of Highly Substituted Indolines and Indoles via Intramolecular [4 + 2] Cycloaddition of Ynamides and Conjugated Enynes

Ynamides react with conjugated enynes in intramolecular [4 + 2] cycloadditions to afford substituted indolines that undergo oxidation with o-chloranil to furnish the corresponding indoles. The cycloaddition substrates are easily assembled from derivatives of 3-butynylamine by Sonogashira coupling with alkenyl halides followed by copper-catalyzed N-alkynylation with acetylenic bromides. Diynamides participate as particularly reactive 2π components in the cycloaddition, providing access to indolines with carbon substituents at the C-7 position. Enynamides serve as 4π components in a complementary version of the cycloaddition strategy which provides access to indoles and indolines substituted with carbon substituents at C-4. These enyne cycloadditions take place upon heating the substrates at 110−210 °C in toluene or 2,2,2-trifluoroethanol and in some cases can be achieved at 0 °C to room temperature in the presence of Lewis acids such as Me2AlCl.
Enantioselective Synthesis of Angularly Substituted 1-Azabicyclic Ring Systems: Dynamic Kinetic Resolution Using Aza-Cope Rearrangements

A useful enantioselective synthesis of angularly substituted 1-azabicyclic molecules that delivers the bicyclic amine products in good yield and 99% ee is reported. Angularly substituted cis-octahydrocyclopenta[b]pyrroles, cis-octahydroindoles, cis-decahydrocyclohepta[b]pyrroles, and cis-octahydrocyclopenta[b]pyridine are formed in good yields and 99% ee exclusively as the cis stereoisomers. Decahydroquinolines are generated as mixtures of cis and trans stereoisomers in similarly high ee. The starting materials for this cascade transformation are assembled in five steps from cycloalkanones and enantiomerically pure (R)-2-phenyl-3-butenamine. This enantioselective synthesis introduces a new strategy for dynamic kinetic resolution in which a rapid tautomeric equilibration of diastereomeric iminium cations is combined with a diastereoselective sigmatropic rearrangement.
Feature Augmentation via Nonparametrics and Selection (FANS) in High-Dimensional Classification

We propose a high-dimensional classification method that involves nonparametric feature augmentation. Knowing that marginal density ratios are the most powerful univariate classifiers, we use the ratio estimates to transform the original feature measurements. Subsequently, penalized logistic regression is invoked, taking as input the newly transformed or augmented features. This procedure trains models equipped with local complexity and global simplicity, thereby avoiding the curse of dimensionality while creating a flexible nonlinear decision boundary. The resulting method is called feature augmentation via nonparametrics and selection (FANS). We motivate FANS by generalizing the naive Bayes model, writing the log ratio of joint densities as a linear combination of those of marginal densities. It is related to generalized additive models, but has better interpretability and computability. Risk bounds are developed for FANS. In numerical analysis, FANS is compared with competing methods, so as to provide ...
What Is the Highest Plausible Redshift of Luminous Quasars

The recent discoveries of luminous quasars at high redshifts imply that black holes more massive than a few billion solar masses were already assembled when the universe was less than a billion years old. We show that the existence of these black holes is not surprising in popular hierarchical models of structure formation. For example, the black hole needed to power the quasar SDSS 1044-0125 at z = 5.8 could arise naturally from the growth of stellar-mass seeds forming at z > 10, when typical values are assumed for the radiative accretion efficiency (~0.1) and the bolometric accretion luminosity in Eddington units (~1). Nevertheless, SDSS 1044-0125 yields a nontrivial constraint on a combination of these parameters. Extrapolating our model to future surveys, we derive the highest plausible redshift for quasars that are not lensed or beamed, as a function of their apparent magnitude. We find that at a limiting magnitude of K ~ 20, quasar surveys can yield strong constraints on the growth of supermassive black holes out to z ~ 10.
Three-dimensional Prestack Inversion, Lobo Trend, South Texas

A-14 THREE-DIMENSIONAL PRESTACK INVERSION LOBO TREND SOUTH TEXAS Summary 1 We demonstrate the difficulty with mapping a Lobo (Paleocene) hydrocarbon reservoir directly from stacked seismic data. A strong response in the stacked volume is ambiguous indicating either a large impedance contrast or a contrast in Poisson’s ratio. That is stacking of reflection amplitudes over offset (or reflection angle) incorporates reflections from impedance perturbations with those due to a change in Poisson’s ratio. Dipole sonic log data indicate Poisson’s ratio but not impedance distinguishes this particular Lobo reservoir from shale. The hydrocarbon reservoir impedance is similar to that of encasing shales.
Large-Scale Structure Effects on the Gravitational Lens Image Positions and Time Delay

We compute the fluctuations in gravitational lens image positions and time delay caused by large-scale structure correlations. We show that these fluctuations can be expressed as a simple integral over the density power spectrum. Using the Cosmic Background Explorer (COBE) normalization we find that positions of objects at cosmological distances are expected to deviate from their true positions by few arcminutes. These deflections are not directly observable. The positions of the images relative to one another fluctuate by a few percent of the relative separation, implying that one does not expect multiple images to be produced by large-scale structure. Nevertheless, the fluctuations are larger than the observational errors on the positions and affect reconstructions of the lens potential. The time delay fluctuations have a geometrical and a gravitational contribution. Both are much larger than the expected time delay from the primary lens, but partially cancel each other. We find that large-scale structure weakly affects the time delay and time delay measurements can be used as a probe of the distance scale in the universe.
The value relevance of a non‐GAAP performance metric to the capital markets

Purpose – The study is driven by concerns raised by standard setters and others about the usefulness of performance reporting under generally accepted accounting principles (GAAP). Of primary interest is whether explicitly defining what information should be included in earnings results in an earnings measure that is more relevant than operating earnings computed according to current GAAP. The purpose of this paper is to explore whether reducing management discretion in the reporting of performance adds to the value relevance of the performance measures reported to capital markets.Design/methodology/approach – The value relevance of this non‐GAAP earnings measure is examined by estimating market valuation and returns models for 518 US firms included in the Standard & Poor's 500 Index over the time period 2002‐2007.Findings – Results show that the explicitly defined non‐GAAP measure used is significantly associated with equity market values and returns and is significantly more value‐relevant than the GAAP...
Who Killed Biafra

Stanley Diamond opens his essay with a euphoric statement by C.O. Ojukwu, the leader of Biafra, who defined Biafra’s endeavour and its relevance to pan-Africanism as the “potential of the black man ... the breaking of the chains” that would demonstrate that the “basis of neo–colonialism has been removed; which is continued economic dominance,” in 1969. This historic milestone still has not been achieved as we concur with the author who in 1970 went on to analyze the reasons for this failure within the context of the larger global frame of reference as applied to the local scene in Nigeria. Diamond’s analysis is still valid and even increasingly relevant in view of globalization, ongoing wars, and current geo-strategic and oil interests confronting our world today. The Igbo people in general and their intellectuals—including the honourees of this special issue—were all affected by the struggle over Biafra in one way or the other.
Tropical hyperplane arrangements and oriented matroids

We study the combinatorial properties of a tropical hyperplane arrangement. We define tropical oriented matroids, and prove that they share many of the properties of ordinary oriented matroids. We show that a tropical oriented matroid determines a subdivision of a product of two simplices, and conjecture that this correspondence is a bijection.
XMM-Newton Observations of Ultraluminous X-Ray Sources in Nearby Galaxies

We examined X-ray spectral and timing properties of ultraluminous X-ray sources (ULXs) in nearby galaxies in XMM-Newton archival data. There appear to be three distinct classes of spectra. One class shows emission from hot, diffuse plasma. This thermal emission is similar to that seen from recent supernovae; the temperatures are in the range 0.6-0.8 keV, and the luminosities are the lowest in our sample, near 1039 ergs s-1. Three sources have spectra that are strongly curved at high energies and have the highest temperatures in our sample, 1.0-1.4 keV. These spectra are well fitted with a power-law plus multicolor disk blackbody model with the power law dominant at low energies or a Comptonization model. The remainder of the sources are best fitted with a power-law plus multicolor disk blackbody model, as is commonly used to describe the spectra of accreting black holes. These sources have the lowest thermal component temperatures, 0.1-0.4 keV, and extend to the highest luminosities, above 1040 ergs s-1. The temperature of the thermal component is in three distinct ranges for the three source classes. This diversity of spectral shapes and the fact that the sources lie in three distinct temperature ranges suggests that the ULXs are a diverse population. Two ULXs that show state transitions stay within a single class over the course of the transition. However, we cannot conclude with certainty that the classes represent distinct types of objects rather than spectral states of a single population of objects. More monitoring observations of ULXs with XMM-Newton are required. We also searched for timing noise from the sources and report detection of noise above the Poisson level from five sources. In three of the sources, the power density spectrum increases with decreasing frequency as a power law down to the lowest frequencies observed, below 10-4 Hz.
Chlorodimethylsulfonium Chloride–Mediated Formation of Phenyl-α-chloroazoalkanes

Phenylhydrazones (1) are efficiently converted into phenyl-α-chloroazoalkanes (2) upon treatment with chlorodimethylsulfonium chloride. Pendent olefins, silyl ethers, and the phenyl ring of the hydrazone are stable to these reaction conditions.
Generation and thermal polymerization of 1-fluoro-2-phenylacetylene

Abstract Some routes to the synthesis of 1-fluoro-2-phenylacetylene were attempted. Although the halogen exchange of chloro- and bromophenylacetylenes and dehydrobromination of dibromofluorophenylacetylene were unsuccessful, defluorosilylation of 1,1- difluoro-2-phenyl-2-trimethylsilylethene (which was prepared by lithiation of bromodifluorovinylbenzene followed by silylation with chlorotrimethylsilane) with CsF gave an oligomer of fluorophenylacetylene. The reaction of the phenyldifluorovinylsilane with CsF in DMF in the presence of phenylazide afforded a 1,3-dipolar cycloadduct, fluorodiphenyl-1,2,3-triazole. Vapor phase vacuum pyrolysis of the phenyldifluorovinylsilane yielded the acetylene, which spontaneously polymerized.
A game theoretic investigation of deception in network security

We perform a game theoretic investigation of the effects of deception on the interactions between an attacker and a defender of a computer network. The defender can employ camouflage by either disguising a normal system as a honeypot or by disguising a honeypot as a normal system. We model the interactions between defender and attacker using a signaling game, a non-cooperative two player dynamic game of incomplete information. For this model, we determine which strategies admit perfect Bayesian equilibria. These equilibria are refined Nash equilibria in which neither the defender nor the attacker will unilaterally choose to deviate from their strategies. We discuss the benefits of employing deceptive equilibrium strategies in the defense of a computer network. Copyright © 2010 John Wiley & Sons, Ltd.
Efficient estimation of the mean time between failures in non-regenerative dependability models

In this paper we discuss fast simulation techniques for estimating the steady-state mean time between failures (MTBF) in non-Markovian models of highly dependable systems. The key is to use a ratio representation of the MTBF, in which the denominator is closely related to the probability of a rare event and is therefore amenable to estimation using importance sampling. A simulation methodology based on splitting and batch means, used for steady-state estimation in non-regenerative systems, can then be employed. Experiments using this methodology yield good results.
HETEROTIC MATRIX THEORY WITH WILSON LINES ON THE LIGHTLIKE CIRCLE

We develop a matrix model for the SO(32) heterotic string with certain Wilson lines on the lightlike circle. This is done by using appropriate T-dualities. The method works for an infinite number of Wilson lines, but not for all. The matrix model is the theory on the D-string of type I wrapped on a circle with a SO(32) Wilson line on the circle. The radius of the circle depends on the Wilson line. This is a 1 + 1-dimensional O(N) theory on a circle. N depends not only on the momentum around the lightlike circle but also on the winding and SO(32) quantum numbers of the state. Perspectives for obtaining a matrix model for all Wilson lines are discussed.
The Laspeyres-Paradox: tax overshifting in nineteenth century Prussia

Following the seminal work of the late nineteenth century economist Etienne Laspeyres I analyse the incidence of the Prussian milling and slaughter tax shortly before its repeal in 1875. A comparison of flour prices in cities which levied this tax with those that did not reveals unusually strong tax overshifting. Modern theories explain overshifting of a specific tax with quality improvements or imperfect competition. In pursuing these ideas I find that it was rather large surplus costs induced by tax collection and monitoring that caused unusually large excess burdens. The reason why the tax remained basically unchanged for more than half a century is that the urban bourgeoisie successfully prevented its repeal, as the alternative would have been the introduction of municipal direct taxes (rent-seeking behaviour).
Blissful Insularity: When Brands are Judged in Isolation from Competitors

The need to evaluate a single brand in isolation, without explicit comparisons to competitors, is ubiquitous in consumer judgment because competitors are often not readily apparent. Although consumers routinely make such judgments, in this paper we show that when a brand is judged in isolation, the judgment is often overly favorable. Moreover, we explore when and why this tendency occurs. Data from 259 participants across 3 experiments that considered very different product categories, and that were conducted with student and adult consumer samples, converge to show that; (1) isolated brand evaluations on average are characterized by a favorableness bias, (2) this bias results from consumers' selective processing of information about the focal brand, (3) favorableness bias is attenuated if context leads consumers to consider alternatives to a salient focal brand, and (4) the isolated brand judgments of experts are much better calibrated than are those of novices.
Data Type Specification: Parameterization and the Power of Specification Techniques

This paper extends our earlier work on abstract data types by providing an algebraic treatment of parametrized data types (e.g., sets-of-(), stacks-of-(), etc.), as well as answering a number of questions on the power and limitations of algebraic specification techniques. In brief: we investigate the “hidden function” problem (the need to include operations in specifications which we want to be hidden from the user); we prove that conditional specifications are inherently more powerful than equational specifications; we show that parameterized specifications must contain “side conditions” (e.g., that finite-sets-of-d requires an equality predicate on d), and we compare the power of the algebraic approach taken here with the more categorical approach of Lehman and Smyth.
Analysis of molecular gas radiation : Real gas property effects

Molecular gas radiation calculations have been performed for CO 2 and H 2 O with a line-by-line high-resolution transmission molecular absorption database, with and without particle scattering. Both line-by-line (Monte Carlo) and K-distribution calculations were conducted. The results confirmed that, if the absorption-coefficient distribution function is sufficiently resolved, essentially line-by-line accuracy can be achieved. In addition, comparison was made between line-by-line results and an exponential wideband model combined with Elsasser narrowband model predictions to assess real gas property effects on radiative heat transfer
THE RELATIONSHIP BETWEEN THE DENSE NEUTRAL AND DIFFUSE IONIZED GAS IN THE THICK DISKS OF TWO EDGE-ON SPIRAL GALAXIES*

We present high-resolution, optical images (BVI + H{alpha}) of the multiphase interstellar medium (ISM) in the thick disks of the edge-on spiral galaxies NGC 4013 and NGC 4302. Our images from the Hubble Space Telescope (HST), Large Binocular Telescope, and WIYN 3.5 m telescope reveal an extensive population of filamentary dust absorption seen to z {approx}2-2.5 kpc. Many of these dusty thick disk structures have characteristics reminiscent of molecular clouds found in the Milky Way disk. Our H{alpha} images show that the extraplanar diffuse ionized gas (DIG) in these galaxies is dominated by a smooth, diffuse component. The strongly filamentary morphologies of the dust absorption have no counterpart in the smoothly distributed H{alpha} emission. We argue that the thick disk DIG and dust-bearing filaments trace physically distinct phases of the thick disk ISM, the latter tracing a dense, warm or cold neutral medium. The dense, dusty matter in the thick disks of spiral galaxies is largely tracing matter ejected from the thin disk via energetic feedback from massive stars. The high densities of the gas may be a result of converging gas flows. This dense material fuels some thick disk star formation, as evidenced by the presence of thick diskmore » H II regions.« less
Evidence for solar wind control of saturn radio emission

Using data collected by the Voyager 1 and 2 spacecraft in 1980 and 1981, strong evidence is presented for a direct correlation between variations in the solar wind at Saturn and the level of activity of Saturn's nonthermal radio emission. Correlation coefficients of 57 to 58% are reached at lag times of 0 to 1 days between the arrival at Saturn of high pressure solar wind streams and the onset of increased radio emission. The radio emission exhibits a long-term periodicity of 25 days, identical to the periodicity seen in the solar wind at this time and consistent with the solar rotation period. The energy coupling efficiency between the solar wind with the Saturn radio emission is estimated and compared with that for Earth.
Demonstration of the zero-crossing phasemeter with a LISA test-bed interferometer

The laser interferometer space antenna (LISA) is being designed to detect and study in detail gravitational waves from sources throughout the Universe such as massive black hole binaries. The conceptual formulation of the LISA space-borne gravitational wave detector is now well developed. The interferometric measurements between the sciencecraft remain one of the most important technological and scientific design areas for the mission. Our work has concentrated on developing the interferometric technologies to create a LISA-like optical signal and to measure the phase of that signal using commercially available instruments. One of the most important goals of this research is to demonstrate the LISA phase timing and phase reconstruction for a LISA-like fringe signal, in the case of a high fringe rate and a low signal level. We present current results of a test-bed interferometer designed to produce an optical LISA-like fringe signal previously discussed in Jennrich O, Stebbins R T, Bender P L and Pollack S (2001 Class. Quantum Grav. 18 4159–64) and Pollack S E, Jennrich O, Stebbins R T and Bender P (2003 Class. Quantum Grav. 20 S291–00).
Linkages among Latin American foreign exchange markets: a long-run perspective in the presence of structural breaks

This article examines stationarity properties, linkages and market efficiency of the Latin American foreign exchange markets over the 1994 to 2005 period. By using daily data for 14 countries we apply bivariate and multivariate cointegration estimations and we further account for the presence of structural breaks or changes in regime. Bivariate cointegration tests revealed that most currencies have a long-run equilibrium relationship with the Brazilian real. Moreover, approximately between 1999 and 2001, there was a shift to a new ‘long-run’ equilibrium relationship.
THE MARKED LENGTH SPECTRUM OF A PROJECTIVE MANIFOLD OR ORBIFOLD

A strictly convex real projective orbifold is equipped with a natural Finsler metric called a Hilbert metric. In the case that the projective structure is hyperbolic, the Hilbert metric and the hyperbolic metric coincide. We prove that the marked Hilbert length spectrum determines the projective structure only up to projective duality. A corollary is the existence of non-isometric diffeomorphic strictly convex projective manifolds (and orbifolds) that are isospectral. This corollary follows from work of Goldman and Choi, and Benoist.
Peer-to-Peer multimedia sharing based on social norms

Designing incentive schemes for Peer-to-Peer (P2P) multimedia sharing applications, where the participating peers find it in their self-interest to contribute resources rather than to ''free-ride'', is challenging due to the unique features exhibited by such networks: large populations of anonymous peers interacting infrequently, asymmetric interests of peers, network errors, multiple concurrent transactions, low-cost implementation requirements, etc. In this paper, to address these challenges, we design and rigorously analyze a new family of incentive protocols that utilizes social norms. In the proposed protocols, each peer maintains a reputation reflecting its past behaviors in the P2P system (i.e. whether the peers have followed or not the social strategy prescribed by the social norm), and the social norm rewards and punishes peers depending on their reputations. We first define the concept of a sustainable social norm, under which no peer has an incentive to deviate from the social strategy prescribed by the protocol. We then formulate the problem of designing optimal social norms, which selects the social norm that maximizes the network performance among all sustainable social norms. In particular, we prove that, given the P2P network and peers' characteristics, social norms can be designed such that it becomes in the self-interest of peers to contribute their contents to the network rather than to free-ride. We also investigate the impact of various punishment schemes on the social welfare as well as how should the optimal social norms be designed if altruistic and malicious peers are active in the network. Our results show that optimal social norms are capable of deterring free-riding behaviors and providing significant improvements in the sharing efficiency of multimedia P2P networks.
The entrepreneurial puzzle: explaining the gender gap

We document the substantial gender gap that exists among university scientists with regard to entrepreneurial activity using a variety of measures and explore factors leading to the disparity. We focus particularly on the biomedical sciences. The contextual explanation that women are under-represented in the types of positions from which faculty typically launch entrepreneurial activity is the most obvious. But the data suggest that for the biomedical sciences context is not sufficient in explaining the entrepreneurial gap. We look elsewhere to factors affecting supply and factors affecting demand. The former include gender differences in attitudes towards risk, competition, “selling” of “science,” type of research and geographic location. The latter include the role of networks, preferences of venture capitalists and “gender discounting.” We explore the associated hypotheses. We provide few tests and conclude that the research agenda is wide open and interesting.
Searching for Circumplanetary Disks around LkCa 15

We present Karl G. Jansky Very Large Array (VLA) observations of the 7 mm continuum emission from the disk surrounding the young star LkCa 15. The observations achieve an angular resolution of 70 mas and spatially resolve the circumstellar emission on a spatial scale of 9 AU. The continuum emission traces a dusty annulus of 45 AU in radius that is consistent with the dust morphology observed at shorter wavelengths. The VLA observations also reveal a compact source at the center of the disk, possibly due to thermal emission from hot dust or ionized gas located within a few AU from the central star. No emission is observed between the star and the dusty ring and, in particular, at the position of the candidate protoplanet LkCa 15 b. By comparing the observations with theoretical models for circumplanetary disk emission, we find that if LkCa 15 b is a massive planet (>5 M_J ) accreting at a rate greater than 10^(–6) M_J yr^(–1), then its circumplanetary disk is less massive than 0.1 M_J , or smaller than 0.4 Hill radii. Similar constraints are derived for any possible circumplanetary disk orbiting within 45 AU from the central star. The mass estimates are uncertain by at least one order of magnitude due to the uncertainties on the mass opacity. Future ALMA observations of this system might be able to detect circumplanetary disks down to a mass of 5 × 10^(–4) M_J and as small as 0.2 AU, providing crucial constraints on the presence of giant planets in the act of forming around this young star.
Ehrenfest theorems and charge antiscreening in Abelian projected gauge theories

Abstract We derive exact relations for SU(2) lattice gauge theory in 3+1 dimensions. In terms of Abelian projection, these are the expectation values of Maxwell equations that define a new field strength operator and conserved, dynamic electric currents formed from the charged matter and ghost fields. The effect of gauge fixing is calculated, and in the maximally Abelian gauge we find antiscreening of U(1) Wilson loop source charges. We discuss the importance of these quantities in the dual superconducting vacuum mechanism of confinement.
Kinetic and metabolic evaluation of new PET ligands for peripheral benzodiazepine receptors

1829 Objectives: Peripheral benzodiazepine receptors (PBRs) are upregulated on activated microglia. The PBR ligand [11C]PK11195 has been used to detect in vivo neuroinflammatory changes but has a high percentage of nonspecific binding. We recently developed three PET ligands based on aryloxyanilides to image PBRs. Our aim was to determine kinetics and metabolism of new PET ligands in monkey and rat brain. Methods: Following studies were performed, 2 baseline (2.5-3 h) and 2 blocking studies (1.5 h) for [11C]PBR01, 5 baseline (2-3 h) and 1 blocking studies (2 h) for [11C]PBR28, and 3 baseline (2-5 h) and 1 blocking studies (2 h) for [18F]PBR06 in rhesus monkeys. Unlabeled PBR01 (1 mg/kg), PBR28 (3 mg/kg) and an aryloxyanilide DAA1106 (3 mg/kg) were used as blocking agents. Arterial input function was obtained in all experiments, and total distribution volumes (VT9s) were calculated using one- (1C) and two-compartment (2C) models. The composition of radioactivity was analyzed in rat brain by HPLC 30 min after injecting radioligands. Results: All PBR ligands showed high brain uptake of 300-400 SUV% and greater specific/nondisplaceable ratio than [11C]PK11195 (Values of VT9s are shown in table). [11C]PBR01: 1C converged but the fitting was poor in all studies. In one of 2 baseline studies, 2C did not converge. [11C]PBR28: Both 1C and 2C converged, and the 2C did not provide significantly better fitting than 1C in all baseline studies. The kinetics was described well by 1C with COV values of VT9≦10%. However, in one of two animals, 120-150 min of scanning was required to obtain apparently stable values of VT9. [18F]PBR06: Both 1C and 2C converged with 5 h data, and 2C provided significantly better fitting than 1C. After 200 min, VT9 by 2C became independent of scan length. In the pre-blocking study, 2C did not converge with poor K4 identifiability. Profiles of plasma radiochromatograms were similar in monkey and rat. Rat brain activity detected as [11C]PBR01, [11C]PBR28 and [18F]PBR06 at 30 min was 83%, 94% and 90%, respectively. Conclusions: Among the three tested PET ligands, [18F]PBR06 and [11C]PBR28 are promising for future use in human. The ratio of specific to nonspecific uptake was unusually high for both tracers (50:1). Based on the current studies, a critical factor for human use will be whether the tracer has adequately fast wash out from brain (relative to the half life of the radionuclide) to obtain stable values of VT9.
Skin Contamination and Absorption of Chemicals from Water and Soil

Contamination of soil and water (ground and surface water) and the transfer of hazardous chemicals is a major concern. When the large surface area of skin is exposed to contaminated soil and water ...
Quinine Synthesis Studies: A Radical−Ionic Annulation via Mn-Mediated Addition to Chiral N-Acylhydrazones

A radical−ionic annulation approach to functionalized perhydroisoquinolines involving Mn-mediated coupling of alkyl iodides and chiral N-acylhydrazones was achieved using only 1.25 equiv of the alkyl iodide. Application of this reaction to alkene-containing substrates en route to quinine offered modest yields, decreasing on scaleup. Control experiments revealed that the alkene interfered with the coupling reaction. A revised approach involving prior oxidation of the alkene offered 93% yield in the Mn-mediated coupling, with the adduct obtained as a single diastereomer.
Laser-induced dispersion control

We present pump-probe measurements that reveal significant changes in the group delay dispersion of a femtosecond laser pulse being controlled by the relative delay between two pulses. We suggest applications for this time-domain shaping approach.
Group testing for image compression

This paper presents group testing for wavelets (GTW), a novel embedded-wavelet-based image compression algorithm based on the concept of group testing. We explain how group testing is a generalization of the zerotree coding technique for wavelet-transformed images. We also show that Golomb coding is equivalent to Hwang's group testing algorithm (Du and Hwang 1993). GTW is similar to SPIHT (Said and Pearlman 1996) but replaces SPIHT's significance pass with a new group testing based method. Although no arithmetic coding is implemented, GTW performs competitively with SPIHT's arithmetic coding variant in terms of rate-distortion performance.
Predicting infant outcome in families of employed and nonemployed mothers

Differences in infant outcome, predictor variables, and their relationships were explored as a function of maternal employment. Thirty 18-month-olds and their mothers were studied. Child intelligence, attachment security, and dependency were measured, as well as frequency of stressful events in the mother's life, quality of the parents' marital relationship, frequency of the mother's social contacts, and extent of the mother's emotional and parenting supports. Also included were the mother's ability to cope; satisfaction with emotional, parenting, and child care supports; and role satisfaction. For children of employed mothers, attachment and dependency were negatively correlated; securely attached children showed less dependency behavior. For employed mothers, satisfaction with child care and frequent social contacts predicted secure child attachment. Satisfaction with child care, role satisfaction, and ability to cope were strongly interrelated. For nonemployed mothers, maternal coping predicted attachment security, while frequent social contacts predicted greater child dependency. Predictors of child outcome were highly interrelated for nonemployed mothers, with satisfaction with emotional supports playing a pivotal role. These differences suggest that different models to predict infant outcome in employed and nonemployed mother families may be appropriate.
New Developments in Deformation Experiments at High Pressure

Although the importance of rheological properties in controlling the dynamics and evolution of the whole mantle of Earth is well-recognized, experimental studies of rheological properties and deformation-induced microstructures have mostly been limited to low-pressure conditions. This is mainly a result of technical limitations in conducting quantitative rheological experiments under high-pressure conditions. A combination of factors is changing this situation. Increased resolution of composition and configuration of Earth’s interior has created a greater demand for well-resolved laboratory measurement of the effects of pressure on the behavior of materials. Higher-strength materials have become readily available for containing high-pressure research devices, and new analytical capabilities—in particular very bright synchrotron X-ray sources—are now readily available to high-pressure researchers. One of the biggest issues in global geodynamics is the style of mantle convection and the nature of chemical differentiation associated with convectional mass transport. Although evidence for deep mantle circulation has recently been found through seismic tomography (e.g., van der Hilst et al. (1997)), complications in convection style have also been noted. They include (1) significant modifications of flow geometry across the mantle transition zone as seen from high resolution tomographic studies (Fukao et al. 1992; Masters et al. 2000; van der Hilst et al. 1991) and (2) complicated patterns of flow in the deep lower mantle (~1500–2500 km), perhaps caused by chemical heterogeneity (Kellogg et al. 1999; van der Hilst and Karason 1999). These studies indicate that while large-scale circulation involving the whole mantle no doubt occurs, significant deviations from simple flow geometry are also present. Two mineral properties have strong influence on convection: (1) density and (2) viscosity (rheology) contrasts. In the past, the effects of density contrast have been emphasized (Honda et al. 1993; Kellogg et al. 1999; Tackley et al. 1993), and the influence of …
Remarks on the Extension of the Ricci Flow

We present two new conditions to extend the Ricci flow on a compact manifold over a finite time, which are improvements of some known extension theorems.
MATRIX THEORY ON ALE SPACES AND WRAPPED MEMBRANES

Abstract We study the properties of wrapped membranes in matrix theory on ALE spaces. We show that the only BPS bound states of wrapped membranes that can form are roots of the A-D-E group. We determine a bound on the energy of a bound state and find the correct dependence on the blow-up parameters and longitudinal momentum expected from M-theory. For the An−1 series, we construct explicit classical solutions for the wrapped membrane bound states. These states have a very rich structure and have a natural interpretation in terms of non-commutative geometry. In the A1 case, we examine the spectrum of excitations around the wrapped membrane solution and provide an explicit calculation of their energies. The results agree exactly with supergravity calculations.
Dynamics of particles with “key-lock” interactions

The dynamics of particles interacting by key-lock binding of attached biomolecules are studied theoretically. Examples of such systems include DNA-functionalized colloids as well as nanoparticles grafted with antibodies to cell membrane proteins. Depending on the coverage of the functional groups, we predict two distinct regimes. In the localized regime at low coverage, the system exhibits an exponential distribution of particle departure times. At higher coverage, there is an interplay between departure dynamics and particle diffusion. This interplay leads to a sharp increase of the departure times, a phenomenon qualitatively similar to aging in glassy systems. This diffusive regime is analogous to dispersive transport in disordered semiconductors: depending on the interaction parameters, the diffusion behavior ranges from standard diffusion to anomalous, subdiffusivebehavior. The connection to recent experiments and implications for future studies are discussed.
Twelve points on the projective line, branched covers, and rational elliptic fibrations

The following divisors in the space \({\rm Sym}^{12}{\mathbb P}^1\) of twelve points on \({\mathbb P}^1\) are actually the same: \(({\mathcal A})\) the possible locus of the twelve nodal fibers in a rational elliptic fibration (i.e. a pencil of plane cubic curves); \(({\mathcal B})\) degree 12 binary forms that can be expressed as a cube plus a square; \(({\mathcal C})\) the locus of the twelve tangents to a smooth plane quartic from a general point of the plane; \(({\mathcal D})\) the branch locus of a degree 4 map from a hyperelliptic genus 3 curve to \({\mathbb P}^1\); \(({\mathcal E})\) the branch locus of a degree 3 map from a genus 4 curve to \({\mathbb P}^1\) induced by a theta-characteristic; and several more. The corresponding moduli spaces are smooth, but they are not all isomorphic; some are finite etale covers of others. We describe the web of interconnections among these spaces, and give monodromy, rationality, and Prym-related consequences. Enumerative consequences include: (i) the degree of this locus is 3762 (e.g. there are 3762 rational elliptic fibrations with nodes above 11 given general points of the base); (ii) if \(C \rightarrow{\mathbb P}^1\) is a cover as in \(({\mathcal D})\), then there are 135 different such covers branched at the same points; (iii) the general set of 12 tangent lines that arise in \(({\mathcal C})\) turn up in 120 essentially different ways. Some parts of this story are well known, and some other parts were known classically (to Zeuthen, Zariski, Coble, Mumford, and others). The unified picture is surprisingly intricate and connects many beautiful constructions, including Recillas' trigonal construction and Shioda's \(E_8\)-Mordell-Weil lattice.
Music and the computer in the sixties

A glance at the cumulative bibliographies published in Computers and the Humanities each year provides ample evidence that there is a striking amount of interest in computer applications for both the art of music and the discipline of musicology. Allen Forte, reporting to the 1967 Fall Joint Computer Conference, noted that connections between music and computing are by no means unique to our time, but extend all the way back into antiquity, when the mathematical ratios of musical intervals were believed to mirror and explain the order of the universe. He then outlined the areas within music using computers and summarized the types of application involved, stressing, however, that much of the work being done was experimental: "It is necessary to say, once and for all, that we are still in a pioneer stage".