cssi/SciSciGPT-SciSciNet huggingface dataset:
Setpoint regulation for stochastically interacting robots

We present an integral feedback controller that regulates the average copy number of an assembly in a system of stochastically interacting robots. The mathematical model for these robots is a tunable reaction network, which makes this approach applicable to a large class of other systems, including ones that exhibit stochastic self-assembly at various length scales. We prove that this controller works for a range of setpoints and how to compute this range both analytically and experimentally. Finally, we demonstrate these ideas on a physical testbed.
A new synthetic method for perfluorocycloimines

Abstract Pyrolysis of alkali salts of perfluoro(cycloamino-substituted acetic) acids provided perfluorocycloimines; a countercation effect was also studied.
Reactions of Per-O-Acetylated Carbohydrate Triflates With Halide Ions

Abstract The reactions of bromide, chloride, and iodide ions with 1,3,4, 6-tetra-O-acetyl-2-O-(trifluoromethylsulfonyl) -α-D-glucopyranose (2) and with 1, 3, 4, 6-tetra-O-acetyl-2-O-(trifluoromethylsulfonyl)-β-D-mannopyranose (3) gave good to excellent yields of the corresponding deoxyhalogeno sugars. In contrast, when the gluco triflate 2 and tetra-butylammonium fluoride were heated under reflux in benzene, only 5-(acetoxymethyl)-2-formylfuran (13) was formed. Reaction of the manno triflate 3 under similar conditions produced 1, 3,4, 6-tetra-O-acetyl-2-deoxy-2-fluoro-β-D-gluco-pyranose (17), 1. 3, 4. 6-tetra-O-acetyl-2-deoxy-β-D-erythro-hex-2-eno-pyranose (18), 4,6-di-O-acetyl-1, 5-anhydro-2-deoxy-D-erythro-hex-l-enitol-3-ulose (19), and 1, 2, 3, 4, 6-penta-O-acetyl-β-D-glucopyranose (20). The mechanisms of the reactions of The triflates 2 and 3 with fluoride ion are discussed.
Bootstrap Resampling as a Tool for Radio Interferometric Imaging Fidelity Assessment

We report on a numerical evaluation of the statistical bootstrap as a technique for radio interferometric imaging fidelity assessment. The development of a fidelity assessment technique is an important scientific prerequisite for automated pipeline reduction of data from modern radio interferometers. We evaluate the statistical performance of two bootstrap methods, the model-based bootstrap and subsample bootstrap, against a Monte Carlo parametric simulation, using interferometric polarization calibration and imaging as the representative problem under study. We find both statistical resampling techniques to be viable approaches to radio interferometric imaging fidelity assessment that merit further investigation. We also report on the development and implementation of a new self-calibration algorithm for radio interferometric polarimetry, which makes no approximations for the polarization source model.
Symmetries in Differential Geometry: a Computational Approach to Prolongations

The aim of this work is to develop a systematic manner to close overdetermined systems arising from conformal Killing tensors (CKT). The research performs this action for 1-tensor and 2-tensors. This research makes it possible to develop a new general method for any rank of CKT. This method can also be applied to other types of Killing equations, as well as to overdetermined systems constrained by some other conditions. The major methodological apparatus of the research is a decomposition of the section bundles where the covariant derivatives of the CKT land via generalized gradients. This decomposition generates a tree in which each row represents a higher derivative. After using the conformal Killing equation, just a few components (branches) survive, which means that most of them can be expressed in terms of lower order terms. This results in a finite number of independent jets. Thus, any higher covariant derivative can be written in terms of these jets. The findings of this work are significant methodologically and, more specifically, in the potential for the discovery of symmetries. First, this work has uncovered a new method that could be used to close overdetermined systems arising from conformal Killing tensors (CKT). Second, through an application of this method, this research finds higher symmetry operators of first and second degree, which are known by other means, for the Laplace operator. The findings also reveal the first order symmetry operators for the Yamabe case. Moreover, the research leads to conjectures about the second order symmetries of the Yamabe operator.
Solvated Electrons on Metal Oxide Surfaces

An electron added to a solvent polarizes its surrounding medium to minimize the free energy. Such an electron with its polarization cloud, which we refer to as the solvated electron, is one of the most fundamental chemical reagents of significant experimental and theoretical interest. The structure and dynamics of solvated electrons in protic solvents have been explored ever since the discovery of intense blue coloration in solutions of alkali metals in ammonia.1-3 Because solvated electrons are the most fundamental chemical reagents as well as carriers of negative charge, substantial experimental and theoretical efforts have focused on elucidating their equilibrium structure and solvation dynamics in a variety of neat liquids.4,5 One of the most important but least explored environments for solvated electrons, namely, the two-dimensional liquid/solid and liquid/vacuum interfaces, is the subject of this review.
Optimum data weighting and error calibration for estimation of gravitational parameters

A new approach has been developed for determining consistent satellite-tracking data weights in solutions for the satellite-only gravitational models. The method employs subset least-squares solutions of the satellite data contained within the complete solution and requires that the differences of the parameters of subset solutions and the complete solution to be in agreement with their error estimates by adjusting the data weights. GEM-T2 model was recently computed and adjusted through a direct application of this method. The estimated data weights are markedly smaller than the weights implied by the formal uncertainties of the measurements. Orbital arc tests as well as surface gravity comparisons show significant improvements for solutions when more realistic data weighting is achieved.
Using query mediators for distributed searching in federated digital libraries

We describe an architecture and investigate the characteristics of distributed searching in federated digital libraries. We introduce the notion of a query mediator as a digital library service responsible for selecting among available search engines, routing queries to those search engines, and aggregating results. We examine operational data from the NCSTRL distributed digital library that reveals a number of characteristics of distributed resource discovery. These include availability and response time of indexers and the distinction between the query mediator view of these characteristics and the indexer view.
Radio Sources from a 31 GHz Sky Survey with the Sunyaev-Zel'dovich Array

We present the rst sample of 31-GHz selected sources to ux levels of 1 mJy. From late 2005 to mid 2007, the Sunyaev-Zel’dovich Array (SZA) observed 7.7 square degrees of the sky at 31 GHz to a median rms of 0:18 mJy=beam. We identify 209 sources at greater than 5 signicance in the 31 GHz maps, ranging in ux from 0.7 mJy to 200 mJy. Archival NVSS data at 1.4 GHz and observations at 5 GHz with the Very Large Array are used to characterize the sources. We determine the maximumlikelihood integrated source count to be N (>S ) = (27:2 2:5 ) deg 2 (SmJy) 1:18 0:12 over the ux range 0 :7 15 mJy. This result is signicantly higher than predictions based on 1.4-GHz selected samples, a discrepancy which can be explained by a small shift in the spectral index distribution for faint 1.4 GHz sources. From comparison with previous measurements of sources within the central arcminute of massive clusters, we derive an overdensity of 6:8 4:4, relative to eld sources. Subject headings: techniques: interferometric, catalogs, surveys, cosmology: cosmic microwave background, cosmology: observations, radio continuum: general
First-Principles Modeling of Phase Equilibria

First-principles approaches to the modeling of phase equilibria rely on the integration of accurate quantum-mechanical total-energy calculations and statistical-mechanical modeling. This combination of methods makes possible parameter-free predictions of the finite-temperature thermodynamic properties governing a material’s phase stability. First-principles, computationalthermodynamic approaches have found increasing applications in phase diagram studies of a wide range of semiconductor, ceramic and metallic systems. These methods are particularly advantageous in the consideration of previously unexplored materials, where they can be used to ascertain the thermodynamic stability of new materials before they are synthesized, and in situations where direct experimental thermodynamic measurements are difficult due to constraints imposed by kinetics or metastability.
Measurement theory and the foundations of utilitarianism

This article reconsiders the Harsanyi–Sen debate concerning whether Harsanyi is justified in interpreting his Aggregation and Impartial Observer Theorems as providing axiomatizations of utilitarianism. Sen's criticism and its formalization by Weymark are based on the claim that von Neumann–Morgenstern utility theory is ordinal, whereas Harsanyi's utilitarian conclusions require cardinal utility. Proposals for overcoming Sen's objection that appeal to formal measurement theory are considered. It is argued that one of these proposals due to Broome and Risse rightly points to a feature of expected utility theory that was ignored by Sen and Weymark, but that this proposal does not provide a normatively compelling justification for cardinal utility. The other proposal due to Broome is shown to make use of a strength of preference relation in addition to the axioms of expected utility theory.
The Box graph in superstring theory

Abstract In theories of closed oriented superstrings, the one-loop amplitude is given by a single diagram, with the topology of a torus. Its interpretation had remained obscure, because it was formally real, converged only for purely imaginary values of the Mandelstam variables, and had to account for the singularities of both the box graph and the one-particle reducible graphs in field theories. We present in detail an analytic continuation method which resolves all these difficulties. It is based on a reduction to certain minimal amplitudes which can themselves be expressed in terms of double and single dispersion relations, with explicit spectral densities. The minimal amplitudes correspond formally to an infinite superposition of box graphs in φ3-like field theories, whose divergence is responsible for the poles in the string amplitudes. This paper is a considerable simplification and generalization of our earlier proposal published in Phys. Rev. Lett. 70 (1993) 3692.
Transition states and mechanisms of the hetero-Diels-Alder reactions of hyponitrous acid, nitrosoalkanes, nitrosoarenes, and nitrosocarbonyl compounds.

The transition states and energetics of Diels−Alder reactions for a variety of nitroso compounds with dienes were explored with density functional theory using the B3LYP functional and 6-31G* basis set. The reactions involve HNO, various nitrosoalkanes and arenes (RNO and ArNO), and nitrosoformaldehyde (CHONO) as dienophiles with butadiene and a series of 1- and 2-substituted dienes. The mechanisms, activation energies, energies of reaction, stereoselectivities, and regioselectivities are predicted for these reactions. These predictions are compared to available experimental data. The mechanism is found to be concerted but involves highly asynchronous transition states. Although it is not evident in the products, we find that the endo path is very strongly favored over the exo alternative due to repulsion between the diene and nitrogen's lone pair. A range of experimental regioselectivities are reproduced by calculations and are found to hinge on a very sensitive balance between FMO interactions, electros...
New skyrmions in the attractive Hubbard model with broken SO(4) symmetry

Abstract The coexistence of superconducting and charge-density-wave order in the half-filled attractive Hubbard model is interpreted as a consequence of the pseudospin SU(2) symmetry spontaneously broken to a `hidden' subgroup U(1). By topological arguments we show that there must exist new skyrmion textures associated with this symmetry breakdown. This fact is illustrated via a non-linear σ -model. Unlike the spin textures previously known in an antiferromagnetic background, doping the model away from half-filling leads the new skyrmions to unwrap.
Chrome-spinel in progressive metamorphism—a preliminary analysis

Progressive metamorphism of serpentinite and allied rocks causes systematic changes in the composition of the chrome-spinel phase, when the latter is in equilibrium with chlorite and two magnesium silicate minerals. The stable spinel in antigorite-serpentinites is Al-poor magnetite, Cr-magnetite, or ferrit-chromite, depending on the local CrFe3+ ratio in the rock. With increasing metamorphic grade up to middle amphibolite facies conditions (talc + olivine, or Ca-poor amphibole + olivine stable) more chromiferous spinels (chromites) are encountered, containing modest amounts of Al. Further increase in grade (enstatite + olivine stable) extends the range of possible spinel compositions to green MgAl2O4-rich spinel. The Al-content is governed by P-, T-, and ƒH2O-sensitive equilibria involving chlorite. MgFe2+ ratios in the spinel are a function of Cr, Al and Fe3+ in the spinel, and the ratio MgFe2+ in coexisting silicates. Solid solution in natural chromites on the magnetite-chromite join is complete at ≈500°C, and close to the join chromite-Al spinel (with variable Fe/Mg) it is complete at ≈700°C. The temperature dependence of KD, the olivine-spinel Fe-Mg partition coefficient, is greater than implied by the jackson (1969) geothermometer. A tentative, revised, graphical calibration is offered, based on microprobe-analyzed high-grade metamorphic pairs and pairs from basaltic pumice. This new plot gives results which are broadly consistent with relative temperatures of equilibration inferred from other geothermometers, for alpine peridotites, peridotite nodules and meteorites.
CONTROLLING ACTIVATED PROCESSES

The rates of activated processes, such as escape from a metastable state and nucleation, are exponentially sensitive to an externally applied field. We describe how this applies to modulation by high-frequency fields and illustrate it with experimental observations. The results may lead to selective control of diffusion in periodic potentials, novel control mechanisms for crystal growth, and new separation techniques.
The diffusivity of hydrogen in nickel at low temperatures

Previous experimental results are discussed to determine the mechanisms of hydrogen diffusion in Ni below 1000 K. The studies cover temperatures down to 273 K, and involved desorption and electrochemical techniques. Constant-current and potentiostatic depletion methods were used to measure diffusivity. The data reveal no hydrogen trapping in well-annealed Ni at temperatures as low as 273 K. The evidence therefore supports the concept of thermally activated diffusion. 14 references.
A One Pot Synthesis of 5,7-Diphenyl-2,3-dihydro-1H-pyrrolizine

Abstract 5,7-Dipheny1-2,3-dihydro-1H-pyrrolizidine was synthesized from dibenzoylmethane and pyrrolidine in one step in 60% yield.
L^P bounds for a maximal dyadic sum operator

The authors prove L p bounds in the range 1<p<∞ for a maximal dyadic sum operator on R n . This maximal operator provides a discrete multidimensional model of Carleson’s operator. Its boundedness is obtained by a simple twist of the proof of Carleson’s theorem given by Lacey and Thiele [7] adapted in higher dimensions [9]. In dimension one, the L p boundedness of this maximal dyadic sum implies in particular an alternative proof of Hunt’s extension [4] of Carleson’s theorem on almost everywhere convergence of Fourier integrals.
Hypernuclei and interactions of kaons with nuclei

Abstract Recent experimental and theoretical progress in hypernuclear physics is reviewed. Different models for hyperon-nucleus central and spin-orbit potentials are compared: several models yield a very small spin-orbit strength for the Λ, as experimentally observed, but differ considerably in their predictions for the Σ. The new data on the 13 Λ C hypernuclear spectrum, as obtained in the (K − ,π − ) strangeness exchange reaction at 800 MeV/c, are discussed. We show how one extracts constraints on the Λ-nucleus and effective Λ-nucleon interactions from the data. The new BNL data on the (K − ,π + ) reaction at 720 MeV c , leading to Σ-hypernuclear states, are examined. We elucidate the case of 6 Li(K − , π + ) 6 Σ H in some detail, and also present some speculations concerning the (K − ,π + ) reaction on other targets. We analyze the physical mechanisms which may lead to unusually narrow Σ excitations in some systems. Finally, we review the physics motivations for several future hyper-nuclear experiments which are already under development, such as (K − ,π − γ) and (π + − ,K + ) studies, or under preliminary consideration, for instance, the (K − ,K + ) reaction producing S = −2 hypernuclei.
Dynamic high pressure: Why it makes metallic fluid hydrogen

Abstract Metallic fluid H has been made by dynamic compression decades after Wigner and Huntington (WH) predicted its existence in 1935. The density at which it was made is within a few percent of the density predicted by WH. Metallic fluid H was achieved by multiple-shock compression of liquid H 2 , which is quasi-isentropic and thermally equilibrated. That is, the compressions were isentropic but for enough temperature and entropy to drive the crossover to completion from H 2 to H at 9-fold compression. The metallic fluid is highly degenerate: T / T F ≈0.014. The basic ideas of dynamic compression, also known as supersonic, adiabatic, nonlinear hydrodynamics, were developed in the last half of the Nineteenth Century in European universities. Today dynamic compression is generally unfamiliar to the scientific community, which impedes general understanding as to why fluid H becomes metallic at a pressure observable in a laboratory. The purposes of this paper are to (i) present a brief review of dynamic compression and its affects on materials, (ii) review considerations that led to the sample holder designed specifically to make metallic fluid H, and (iii) present a brief inter-comparison of dynamic and static methods to achieve high pressure relative to their prospects for making metallic H.
Photoelectric intensity measurements in the iron arc

Summary Techniques are described which permit the measurement of spectral intensities in general with an accuracy of better than one per cent, using multiplier phototubes and a recently developed electronic pen and ink ratio recorder. (The phototubes are linear and with a tungsten lamp sensitivity calibration accurate intensity measurement over wide wave length intervals are now possible.) The recorder measures the intensity ratio from two phototubes, so that a fixed tube may serve as a monitor for one which scans the spectrum, in this way cancelling out intensity fluctuations of the source. In this manner direct quantitative studies of light source properties are possible. As a particular application, relative intensities of over 1,000 Unes from a standard d.c. iron arc were measured. Quantitative data are also given for self-absorption and the variation of the intensities with excitation conditions. The iron arc may be used as an intensity standard for many applications.
Newton's Pen: A pen-based tutoring system for statics

We present Newton's Pen, a statics tutor implemented on a ''pentop computer,'' a writing instrument with an integrated digitizer and embedded processor. The tutor, intended for undergraduate education, scaffolds students in the construction of free body diagrams and equilibrium equations. This project entailed the development of sketch understanding techniques and user interface principles for creating pedagogically sound instructional tools for pentop computers. Development on the pentop platform presented novel challenges because of limited computational resources and a visually static, ink-on-paper display (the only dynamic output device is an audio speaker). We show that a system architecture based on a finite state machine serves as a convenient means for providing context-sensitive tutorial help. We also demonstrate the effectiveness of an instructional model based on a structured solution process with feedback provided at each problem-solving step. This model is designed to match the pentop's unusual user interface capabilities. Our three user studies suggest that Newton's Pen is an effective teaching tool.
Anisotropic etching of silicon in hydrazine

Abstract This paper contains a detailed discussion of the practical issues related to the anisotropic etching of single crystal silicon using a 5050 hydrazinewater solution. Characteristics of the etchant, etching reactor design, etch procedures, safety precautions, etch rate data for typical samples and appropriate etch-masks are among the topic discussed. The etching process is carried out in a atmospheric reflux reactor, continuously purged with nitrogen. The etch rate of (100) silicon at 115°C in this hydrazine solution is nearly 3 μm/min, which is much higher than that of ethylenediaminepyrocatecholwater (EDP) solutions. Silicon dioxide, silicon nitride and most metallic thin films, except aluminium, can be used to mask the etching process. The etch rate is reduced significantly in highly-boron-doped silicon; a boron concentration of 1.5 × 10 20 cm −3 practically stops the etch. The use of the hydrazine solution for micromachining thin silicon diaphragms, cantilevers and fibers is demonstrated.
Finland: increases in alcohol availability and consumption.

This article briefly describes the changes that Finland has undergone during the 1960–2012 period with regards to societal changes, alcohol control policies, alcohol-related harms, and alcohol consumption, after which the findings of the analyses made by Allamani and his colleagues in the AMPHORA project are discussed. It seems that despite the changes in the alcohol field, the strong and comprehensive control policy measures still have a solid footing in the Finnish society. It is also evident that the policy changes implemented over the course of the last decades have affected the development of the total alcohol consumption to a large degree in both positive and negative directions, depending on the kind of measure implemented.
DOCUMENT STRUCTURES: A SURVEY

Knowing the structure of a document is the key to successful processing of a document. There exist a variety of definitions of document structures. This paper is a survey of methods describing document structures. Several novel concepts and theoretical analyses are also presented. A document not only has a concrete two-dimensional image but also a conceptual structure which corresponds to human’s thinking. The process of publishing or writing corresponds to encoding the conceptual structure into a concrete structure. Conversely, the concrete structure of the document is decoded into its conceptual one in document processing. In this paper, conceptual and concrete structures are introduced. A complete system for treating both of the conceptual and concrete structures is probably still decades away. As the first stage, this study puts some emphasis on concrete structures, for which, geometric, logical, textual, information, textural, and other structures are described.
On the feasibility of using Smoothed Particle Hydrodynamics for underwater explosion calculations

SPH (Smoothed Particle Hydrodynamics) is a gridless Lagrangian technique which is appealing as a possible alternative to numerical techniques currently used to analyze high deformation impulsive loading events. In the present study, the SPH algorithm has been subjected to detailed testing and analysis to determine the feasibility of using PRONTO/SPH for the analysis of various types of underwater explosion problems involving fluid-structure and shock-structure interactions. Of particular interest are effects of bubble formation and collapse and the permanent deformation of thin walled structures due to these loadings. These are exceptionally difficult problems to model. Past attempts with various types of codes have not been satisfactory. Coupling SPH into the finite element code PRONTO represents a new approach to the problem. Results show that the method is well-suited for transmission of loads from underwater explosions to nearby structures, but the calculation of late time effects due to acceleration of gravity and bubble buoyancy will require additional development, and possibly coupling with implicit or incompressible methods.
Costs of Equity Capital and Model Mispricing

Costs of equity for individual firms are estimated in a Bayesian framework using several factor-based pricing models. Substantial prior uncertainty about mispricing often produces an estimated cost of equity close to that obtained with mispricing precluded, even for a stock whose average return departs significantly from the pricing model's prediction. Uncertainty about which pricing model to use is less important, on average, than within-model parameter uncertainty. In the absence of mispricing uncertainty, uncertainty about factor premiums is generally the largest source of overall uncertainty about a firm's cost of equity, although uncertainty about betas is nearly as important. Copyright The American Finance Association 1999.
Understanding the American Decline in Social Capital, 1952–1998

Social capital describes both the relations across and within families. Loury(1977) emphasized the importance of social capital within the home for the de-velopment of children. These relations between parents and children and organ-izations and individuals are valuable because they increase trust between indi-viduals and allow them to work together to achieve common economic andpolitical goals. Tocqueville (1840/1981, pp.137–141) argued that democraticcountries that lost the habit of association would ﬁnd their very civilizations inperil because they had no other substitutes for reciprocal action. His contentionthat voluntary associations help democracies function is supported by a largebody of empirical research. For example, Brady, Verba, and Schlozman (1995)argue that skills in political participation are acquired in such non-political in-
Motivation and Participation: An Integration

An integration of the rational model of expectancy theory and the “caring for people” philosophy of the participative approach to employee motivation is presented. The paper describes four ways in ...
Quantitative Analysis of Literary Styles

Writers are often viewed as having an inherent style that can serve as a literary fingerprint. By quantifying relevant features related to literary style, one may hope to classify written works and even attribute authorship to newly discovered texts. Beyond its intrinsic interest, the study of literary styles presents the opportunity to introduce and motivate many standard multivariate statistical techniques. Today the statistical analysis of literary styles is made much simpler by the wealth of real data readily available from the Internet. This article presents an overview and brief history of the analysis of literary styles. In addition we use canonical discriminant analyis and principal component analysis to identify structure in the data and distinguish authorship.
It'll Probably Work Out: Improved List-Decoding Through Random Operations

In this work, we introduce a framework to study the effect of random operations on the combinatorial list decodability of a code. The operations we consider correspond to row and column operations on the matrix obtained from the code by stacking the codewords together as columns. This captures many natural transformations on codes, such as puncturing, folding, and taking subcodes; we show that many such operations can improve the list-decoding properties of a code. There are two main points to this. First, our goal is to advance our (combinatorial) understanding of list-decodability, by understanding what structure (or lack thereof) is necessary to obtain it. Second, we use our more general results to obtain a few interesting corollaries for list decoding.
The total synthesis of (-)-SNF4435 C and (+)-SNF4435 D.

The size and positioning of substituents on a tetraene, along with the Woodward−Hoffmann rules, control the relative stereochemistry at the four adjacent chiral centers that are generated in the 8π/6π electrocyclization cascade. A biomimetic synthesis of (−)-SNF4435 C and (+)-SNF4435 D exploits these steric effects and allows confirmation of the predicted absolute stereochemistry of the natural products.
Combinatorial chemistry using polymer-supported reagents

During the past several years, the field of combinatorial chemistry has expanded to include not only solid- and solution-phase methods for expedited compound synthesis, but also hybrid approaches that span these two extremes. In particular, polymer-supported reagents have emerged as useful combinatorial chemistry tools for the discovery and optimization of new pharmaceutical leads.
Establishing vicinal proton‐proton connectivities using two‐dimensional proton zero quantum coherence NMR

Phenanthro[3,4:3′,4′]phenanthro[2,1-b]thiophene (1) served as the model system to evaluate two-dimensional proton zero quantum coherence nmr in order to establish the vicinal proton-proton connectivities. The utility of the two-dimensional proton zero quantum nmr experiment has been compared with the utility of the traditional autocorrelated proton-proton (COSY) experiment. In the case of a molecule such as 1, where the proton chemical shifts are so highly congested, the zero quantum coherence experiment provides data not obtainable from the COSY experiment.
Effects of a Hard Limiting Repeater on the Performance of a DPSK Data Transmission System

Although the effects of a hard-limiting repeater on coherent phase shift keying (CPSK) data transmission systems have been studied, corresponding effects pertaining to differential phase shift keying (DPSK) systems are yet to be examined. The present paper contains the results of a study on DPSK data detection performance when a hard-limiting repeater is part of the overall data link under consideration, and white Gaussian noise is introduced at the repeater and receiver front ends; the extension to the multi-link system, containing cascaded hard-limiting repeaters, is also included. The results obtained were found to be analogous to those of previous CPSK studies. Specifically, the inclusion of the hard-limiter was generally shown to improve probability of error performance when downlink noise is present. A comparison of present results with those of previous ones for corresponding CPSK systems shows that DPSK is degraded noticeably more by downlink noise than its CPSK counterpart.
A theoretical model for single-molecule incoherent scanning tunneling spectroscopy

Single-molecule scanning tunneling spectroscopy (STS), with dephasing due to elastic and inelastic scattering, is of some current interest. Motivated by this, we report an extended Huckel theory (EHT)-based mean-field non-equilibrium Green's function (NEGF) transport model with electron–phonon scattering treated within the self-consistent Born approximation (SCBA). Furthermore, a procedure based on EHT basis set modification is described. We use this model to study the effect of the temperature-dependent dephasing due to low lying modes in the far-infrared range for which , on the resonant conduction through the highest occupied molecular orbital (HOMO) level of a phenyl dithiol molecule bonded to fcc-Au(111) contact. We finally propose to include dephasing in room temperature molecular resonant conduction calculations.
An analysis of nondeductible IRA contributions and Roth IRA conversions

Abstract On average investors have an income replacement rate of 64% of their pre-retirement income, which in many cases results in a lower tax rate in retirement. We analyze the impact of declining withdrawal tax rates on the choice between taxable mutual fund investments and nondeductible IRAs. The relative attractiveness of the taxable mutual fund option declines significantly when withdrawal tax rates decline. Converting existing IRAs to Roth IRAs is generally beneficial for investors who remain in the same tax bracket upon withdrawal. For short (long) time horizons and low (high) expected returns, the marginal value of conversion in 1998 is greater (less) than the marginal value of optimal conversion. For investors dropping into the 15% tax bracket, conversion is generally not beneficial unless the conversion is done optimally, the time horizon is long, and the expected return is high. Investors in the 15% tax bracket should convert existing IRA assets.
Synthetic Efforts toward the Lycopodium Alkaloids Inspires a Hydrogen Iodide Mediated Method for the Hydroamination and Hydroetherification of Olefins

Progress toward the total syntheses of a diverse set of fawcettimine-type Lycopodium alkaloids via a "Heathcock-type" 6-5-9 tricycle is disclosed. This route features an intermolecular Diels-Alder cycloaddition to rapidly furnish the 6-5-fused bicycle and a highly chemoselective directed hydrogenation to build the azonane fragment. While conducting these synthetic studies, trimethylsilyl iodide was found to effect a hydroamination reaction to furnish the tetracyclic core of serratine and related natural products. This observation has been expanded into a general method for the room temperature hydroamination of unactivated olefins with tosylamides utilizing catalytic "anhydrous" HI (generated in situ from trimethylsilyl iodide and water). The presence of the iodide anion is critical to the success of this Bronsted acid catalyzed protocol, possibly due to its function as a weakly coordinating anion. These conditions also effect the analogous hydroetherification reaction of alcohols with unactivated olefins.
(2S, 3S, 5S)- and (2S, 3S, 5R)-5-carboxaldehyde-2,3-diphenyl-1,4-dioxane as surrogates for optically pure 2,3-O-isopropylideneglyceraldehyde in asymmetric synthesis

Abstract The title compounds were prepared from threo -hydrobenzoin, either enantiomer of which is readily available from trans -stilbene using the Sharpless asymmetric dihydroxylation reaction. Several organometallic reagents were added to the aldehydes and the resulting adducts treated with H 2 -Pd/C to give diastereomerically and enantiomerically enriched 1,2,3-triol-containing building blocks for asymmetric synthesis.
Neighborhood wealth distributions

Abstract This paper uses data from the neighborhood clusters sample of the 1989 American Housing Survey and the Panel Study of Income Dynamics and its 1989 wealth supplement to study the distribution of wealth within US residential neighborhoods. It uses the Bourguignon decomposable inequality index and finds that wealth is more unequally distributed than income, and income more than housing wealth, at all levels of aggregation, that is, neighborhoods, metropolitan areas, regions and the entire US.
Motor drive system EMI reduction by asymmetric interleaving

Parallel operation of PWM rectifiers and inverters has been used in UPS, motor drives, telecom power supply, and other applications to reduce system development cost and to provide easy power scalability as well as redundancy. Conventional symmetric interleaving can eliminate certain harmonics and their sideband components but is not necessarily optimal for EMI filter design if the filter attenuation requirements are determined by one of the remaining harmonics. This paper demonstrates the application of asymmetric interleaving in modular three-phase motor drives to minimize their output EMI filter size. Experimental measurements show that compared to symmetric interleaving, optimized asymmetric interleaving can reduce EMI attenuation requirements by an additional 6–8 dB, resulting in significant reduction in both CM and DM filter size and weight.
A Search for Intraday Variability in the Blazar PKS 2005−489

Rapid, multicolor optical monitoring carried out for a multiwavelength campaign during 2000 August 22–27 is presented for the bright and variable BL Lac object PKS 2005-489. Previous multiwavelength monitoring campaigns of PKS 2005-489 have found complex variability behavior both in flux density and in broadband spectrum, with different modes and timescales from days to hours. During this campaign PKS 2005-489 was observed to be in an unusual state, bright in the optical but faint in the X-ray, just prior to an X-ray flare that began on 2000 September 2. PKS 2005-489 was also observed to have a flatter optical spectrum than in prior epochs. A linear increase in optical flux density was observed during the first 5.2 days of the campaign. However, intraday and color variability were not detected. The large discrepancy between the ratio of X-ray to optical flux density observed during this campaign and that observed in prior epochs indicates a lack of long-term correlation between the two wave bands, and it illustrates that simple particle injection events in the jet are insufficient to explain the long-term variability behavior of this object. Twenty-three in-field standard stars are identified for future optical monitoring programs.
Spectral Models of Advection‐dominated Accretion Flows with Winds

We calculate spectral models of advection-dominated accretion flows, taking into account the possibility that significant mass may be lost to an outflow/wind. We apply the models to the soft X-ray transient V404 Cyg in quiescence, the Galactic center source Sgr A*, and the nucleus of NGC 4649. We show that there are qualitative degeneracies between the mass-loss rate in the wind and parameters characterizing the microphysics of the accretion flow; of particular importance is δ, the fraction of the turbulent energy which heats the electrons. For small δ, current observations suggest that at most 90% of the mass originating at large radii is lost to a wind, so that at least ~10% reaches the central object. For large δ ~ 0.3, however, models with significantly more mass loss are in agreement with the observations. We conclude by highlighting future observations which may clarify the importance of mass loss in sub-Eddington accretion flows.
SYNTHESIS OF HALOGEN-SUBSTITUTED 3-DEAZAADENOSINE AND 3-DEAZAGUANOSINE ANALOGUES AS POTENTIAL ANTITUMOR/ANTIVIRAL AGENTS

Various 2-halogen-substituted analogues (38, 39, 43 and 44), 3-halogen-substituted analogues (51 and 52), and 2',3'-dihalogen-substituted analogues (57-60) of 3-deazaadenosine and 3-halogen-substituted analogues (61 and 62) of 3-deazaguanosine have been synthesized as potential anticancer and/or antiviral agents. Among these compounds, 3-deaza-3-bromoguanosine (62) showed significant cytotoxicity against L1210, P388, CCRF-CEM and B16F10 cell lines in vitro, producing IC50 values of 3, 7, 9 and 7 microM, respectively. Several 3-deazaadenosine analogues (38, 51, 57 and 59) showed moderate to weak activity against hepatitis B virus.
Gauge invariance and mass gap in (2+1)-dimensional Yang-Mills theory

In terms of a gauge-invariant matrix parametrization of the fields, we give an analysis of how the mass gap could arise in non-Abelian gauge theories in two spatial dimensions.
Boronyls as key structural units in boron oxide clusters: B(BO)2- and B(BO)3-.

Even though BO- is isoelectronic with CN-, the chemistry of BO- is relatively unknown. Here we report the first combined photoelectron spectroscopy and computational evidence that BO is a robust inorganic ligand that governs structural and electronic properties in B3O2- and B4O3-. Both anions yield similar and simple vibrationally resolved photoelectron spectra. Theoretical calculations reveal that B3O2- possesses a linear OBBBO- structure (D∞h, 3Σg) and B4O3- is a triangular B(BO)3- cluster (D3h, 2A2‘ ‘), which can be viewed as two and three boronyls bonded to a single B atom, respectively. The current finding suggests that boronyls may be key structural units in boron-rich boron oxide cluster and they can be used to design novel boronyl compounds.
Using GIS to improve highway safety

In the United States the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991 has encouraged the development of information management systems. GIS, to promote safety and efficient expenditure of public resources, is an example. This paper therefore describes the development of a traffic safety GIS prototype for spatial analysis of traffic collisions in Honolulu, Hawaii. Various classes of spatial analyses, which involve points, segments, and zones, with special reference to the nature of motor vehicle collisions and traffic safety research, have been developed.
Tellurium tetrachloride: Addition to cyclohexene and preparation from tellurium dioxide and trimethylchlorosilane

Tellurium dioxide, trimethylchorosilane, acetyl chloride, or acetyl bromide in glacial acetic acid generated a homogeneous solution. Addition of cyclohexene produced trans-2-halocyclohexyl tellurium trihalides of excellent purity in 70% yield. With dichloromethane or ethanol-free chloroform the same compounds were obtained from heterogeneous reaction mixtures. trans-2-Methoxycyclohexyl tellurium trichloride was obtained quantitatively from tellurium dioxide, trimethylchlorosilane, and cyclohexene in absolute methanol. In the absence of cyclohexene, tellurium tetrachloride was obtained in 91% yield from tellurium dioxide and trimethylchlorosilane in chloroform, and tellurium tetrabromide in 98% yield from tellurium dioxide and acetyl bromide in glacial acetic acid.
Tension perturbations of black brane spacetimes

We consider black brane spacetimes that have at least one spatial translation Killing field that is tangent to the brane. A new parameter, the tension of a spacetime, is defined. The tension parameter is associated with spatial translations in much the same way that the ADM mass is associated with the time translation Killing field. In this work, we explore the implications of the spatial translation symmetry for small perturbations around a background black brane. For static-charged black branes we derive a law which relates the tension perturbation to the surface gravity times the change in the horizon area, plus terms that involve variations in the charges and currents. We find that as a black brane evaporates the tension decreases. We also give a simple derivation of a first law for black brane spacetimes. These constructions hold when the background stress–energy is governed by a Hamiltonian, and the results include arbitrary perturbative stress–energy sources.
The Changing Role of Higher Education in the United States

Abstract The role of higher education has changed in the United States. It has become a learning society where egalitarian pressures for equal opportunities led to the expansion of educational services to broader and more representative segments of society. Five propositions illustrate the current pressures for change. (1) Institutions of higher education no longer enjoy a monopoly on the provision of educational services. The learning society has given higher education new competition for the growing adult market. (2) The roles of education providers are increasingly blurred. (3) Higher education no longer has the full‐time commitment of students or of faculty. (4) Lifelong learning has become a lifelong necessity for almost everyone, which demands flexibility and responsiveness to change on the part of higher education. (5) A change is needed in the methods of teaching and learning to accommodate adult learners and to provide for the long‐ range needs of the learning society.
Adaptive Nonlinear Model-Based Fault Diagnosis of Li-Ion Batteries

In this paper, an adaptive fault diagnosis technique is used in Li-ion batteries. The diagnosis process consists of multiple nonlinear models representing signature faults, such as overcharge and overdischarge, causing significant model parameter variation. The impedance spectroscopy of a Li-ion $(\hbox{LiFePO}_{4})$ cell is used, along with the equivalent circuit methodology, to construct nonlinear battery signature-fault models. Extended Kalman filters are utilized to estimate the terminal voltage of each model and to generate residual signals. The residual signals are used in the multiple-model adaptive estimation technique to generate probabilities that determine the signature faults. It can be seen that, by using this method, signature faults can be detected accurately, thus providing an effective way of diagnosing Li-ion battery failure.
A Furstenberg-Katznelson-Weiss type theorem on (d+1) -point configurations in sets of positive density in finite field geometries

We show that if E@?F"q^d, the d-dimensional vector space over the finite field with q elements, and |E|>=@rq^d, where q^-^1^2@?@r@?1, then E contains an isometric copy of at least c@r^d^-^1q^d^+^1^2 distinct (d+1)-point configurations.
Preparation and Characterization of Tetraphenylborate Salts of 2-Aminopyrrole and 1-Alkyl-2-aminopyrroles

Tetraphenylborate salts of 2-aminopyrrole and 1-alkyl-2-aminopyrroles are prepared and found to be stable.
Threshold Level Photoablation Of Metals: Ejected Ion Energy Distributions

Laser sources can create plasmas at metallic surfaces when radiation fluxes are above 106 W/cm2. These plasmas grow rapidly, absorbing the incident laser radiation and strongly influencing the laser coupling to the surface.
Type II intramolecular annulations between vinylcarbenoids and furans

Abstract Rhodium(II) octanoate catalyzed intramolecular reactions between vinyldiazomethanes and furans result in the formation of polycyclic systems by a tandem cyclopropanation/Cope rearrangement.
Estimating projections of the playable set

The playable set in differential game theory is the set of points in state space where a pursuer can guarantee capture of an evader under all possible control actions of the evader to the contrary. For problems of low dimension (one, two, and, perhaps, three dimensions), the playable set usually can be constructed using the necessary conditions provided by the payability max-min principle. This principle provides controls for both the pursuer and the evader that will drive the system along the boundary of the playable set. We show here that, for a number of higher-dimensional problems, the playability max-min principle can still be used to estimate the projection of a higher-dimensional playable set onto a lower dimension (usually one or two dimensions). This is done by finding both an overestimate and an underestimate for such a projection. This procedure is used to re-examine some previously published results on aircraft collision avoidance.
Polarization and Extent of Maser Emission from Late-Type Stars: Support for a Plasma Turbulence Model of Maser Production

The integrated spectrum of OH emission from late-type stars is often circularly polarized, by as much as 50% in some cases. While the spectra are partially polarized, the individual maser components revealed by VLBI are much more so. Using VLBI observations of late-type stars from the literature, we show that the difference in circular polarization between main lines correlates with a difference in angular extent for a given object. This is a natural result if turbulent magnetic fields are causing the masers to be polarized via the Cook mechanism and might serve as a good diagnostic for determining which objects should be investigated in the search for magnetic fields around evolved stars.
Soft apertures for reducing damage in high-power laser-amplifier systems

Abstract Soft apertures have been constructed for tailoring the spatial profile of a light beam to minimize harmful diffraction effects that lead to self-focusing and consequent damage while still enabling substantial energy extraction from amplifiers.