cssi/SciSciGPT-SciSciNet huggingface dataset:
Reciprocity-enhanced optical communication through atmospheric turbulence - part I: reciprocity proofs and far-field power transfer optimization

Turbulence-induced scintillation is the principal impairment to Gbps laser communication over clear-weather atmospheric paths. This paper, plus its companion [A. Puryear, J. H. Shapiro, and R.R. Parenti, “Reciprocity- Enhanced Optical Communication through Atmospheric Turbulence—Part II: Communication Architectures and Performance”], introduce and analyze the exploitation of atmospheric reciprocity for combating turbulence. Part I presents reciprocity proofs that apply under rather general conditions and underlie the communication performance analysis in Part II.
Polarized lepton nucleon scattering — summary of the theory talks on spin physics at DIS 99

Abstract We summarize the theory talks given in Working Group 4 ‘Polarized Lepton Nucleon Scattering’ at the DIS 99 workshop. The significant progress made over the last year on many of the interesting topics in ‘spin physics’ is documented.
Globular Cluster Abundances from High-Resolution Integrated-Light Spectra. I. 47 Tuc

We describe the detailed chemical abundance analysis of a high-resolution ( -->R ~ 35,000), integrated-light (IL), spectrum of the core of the Galactic globular cluster 47 Tuc, obtained using the du Pont echelle at Las Campanas. We develop an abundance analysis strategy that can be applied to spatial unresolved extragalactic clusters. We have computed abundances for Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Ba, La, Nd, and Eu. For an analysis with the known color-magnitude diagram (CMD) for 47 Tuc we obtain a mean [Fe/H] value of -->-0.75 ? 0.026 ? 0.045 dex (random and systematic error), in good agreement with the mean of five recent high-resolution abundance studies, at ?0.70 dex. Typical random errors on our mean [X/Fe] ratios are 0.07-0.10 dex, similar to studies of individual stars in 47 Tuc. Na and Al appear enhanced, perhaps due to proton burning in the most luminous cluster stars. Our IL abundance analysis with an unknown CMD employed theoretical Teramo isochrones; however, we apply zero-point abundance corrections to account for the factor of 3 underprediction of stars at the AGB bump luminosity. While line diagnostics alone provide only mild constraints on the cluster age (ruling out ages younger than ~2 Gyr), when theoretical IL -->B ? V colors are combined with metallicity derived from the Fe I lines, the age is constrained to 10-15 Gyr and we obtain -->[ Fe/H ] = ? 0.70 ? 0.021 ? 0.052 dex. We find that Fe I line diagnostics may also be used to constrain the horizontal-branch morphology of an unresolved cluster. Lastly, our spectrum synthesis of 5.4 million TiO lines indicates that the 7300-7600 ? TiO window should be useful for estimating the effect of M giants on the IL abundances, and important for clusters more metal-rich than 47 Tuc.
InSb: A Key Material for IR Detector Applications

InSb has served as an important mid-wave IR (λ=3−5μm) detector material for several decades. In this presentation, we will briefly review General Electric’s InSb Charge Injection Device technology. Emphasis will be placed on device performance as a function of material parameters. A new InSb materials technology utilizing liquid phase epitaxy will be described. This epitaxial growth technology improves InSb material parameters and increases minority carrier lifetimes by more than two orders of magnitude to near the Auger limit. Comparisons will be made between available bulk material parameters and that of the epitaxial material.
Real Cubic Surfaces and Real Hyperbolic Geometry

Abstract The moduli space of stable real cubic surfaces is the quotient of real hyperbolic four-space by a discrete, nonarithmetic group. The volume of the moduli space is 37 π 2 /1080 in the metric of constant curvature −1. Each of the five connected components of the moduli space can be described as the quotient of real hyperbolic four-space by a specific arithmetic group. We compute the volumes of these components. To cite this article: D. Allcock et al., C. R. Acad. Sci. Paris, Ser. I 337 (2003).
2011--2012 Gary L. Lilien ISMS-MSI Practice Prize Competition---Special Section Introduction

I introduce the work of the finalists in the 2011--2012 Gary L. Lilien ISMS-MSI Practice Prize Competition, representing once again the best combinations of rigor and relevance produced by marketing scientists. The winning paper is by a team who developed an innovative approach to measuring the impact of a social media campaign for an Indian premium ice cream retailer, Hokey Pokey. The other two finalists are from a team that developed a category management tool for a leading wine brand, Beringer, and a team that developed a system called PROSAD, which determines optimal bids to maximize an advertiser's profit per search engine advertising keyword.
COLEMAN–DE LUCCIA TUNNELING AND THE GIBBONS–HAWKING TEMPERATURE

We study Coleman–de Luccia tunneling in some detail. We show that, for a single scalar field potential with a true and a false vacuum, there are four types of tunneling, depending on the properties of the potential. A general tunneling process involves a combination of thermal (Gibbons–Hawking temperature) fluctuation part way up the barrier followed by quantum tunneling. The thin-wall approximation is a special limit of the case (of only quantum tunneling) where inside the nucleation bubble is the true vacuum while the outside reaches the false vacuum. Hawking–Moss tunneling is the (only thermal fluctuation) limit of the case where the inside of the bubble does not reach the true vacuum at the moment of its creation, and the outside is cut off by the de Sitter horizon before it reaches the false vacuum. A typical tunneling process is a combination of thermal and quantum tunnelings. We estimate the tunneling rate for this case and find that the corrections to the Hawking–Moss formula can be large. In all cases, we see that the Euclidean action of the bounce decreases rapidly as the vacuum energy density increases, signaling that the tunneling is not exponentially suppressed. This phenomenon may be interpreted as a finite temperature effect due to the Gibbons–Hawking temperature of the de Sitter space. As an application, we discuss the implication of this tunneling property to the cosmic landscape.
Discovery of a New Dusty B[E] Star in the Small Magellanic Cloud

We present new optical spectroscopic and Spitzer IRAC photometric observations of a B-type star in the SMC cluster NGC 346, NGC 346:KWBBe 200. We detect numerous Fe II, [O I], [Fe II], as well as strong P-Cygni profile H I emission lines in its optical spectrum. The star's near-IR color and optical to IR SED clearly indicate the presence of an infrared excess, consistent with the presence of gas and warm, T -800 K, circumstellar dust. Based on a crude estimate of the star's luminosity and the observed spectroscopic line profile morphologies, we find that the star is likely to be a B-type supergiant. We suggest that NGC 346:KWBBe 200 is a newly discovered B[e] supergiant star, and represents the fifth such object to be identified in the SMC.
Synthesis of 2-[18F]Fluoroestradiol, a Potential Diagnostic Imaging Agent for Breast Cancer: Strategies to Achieve Nucleophilic Substitution of an Electron-Rich Aromatic Ring with [18F]F-

To improve the pharmacokinetics of fluorine-18 labeled estrogens to be used as receptor-based imaging agents for the identification and staging of estrogen-receptor-positive breast carcinoma, we wanted to synthesize 2-[(18)F]fluoroestradiol. This compound has high affinity for the estrogen receptor and also binds very well to sex hormone binding globulin, a protein thought to protect estrogens from metabolism and deliver them to target tissues. We anticipated that this compound might have increased tumor uptake and reduced uptake in the liver. The synthesis of a [(18)F]fluoroaryl estrogen at the high specific activity, no-carrier-added level requires the use of [(18)F]F(-) as a precursor. Several strategies were explored for the synthesis of a [(18)F]fluoroaryl estrogen. The synthesis of 2-[(18)F]fluoroestradiol was eventually achieved by [(18)F]fluoride ion displacement of a trimethylammonium leaving group at C-2 of an estrogen, with additional activation being provided by a 6-keto group which was subsequently removed by reduction. Incorporation yields of fluorine-18 were between 20% and 50%. The potential of this new radiopharmaceutical as an imaging agent is being evaluated in an appropriate animal model.
Maximizing the resonant displacement of piezoelectric beams

The paper presents a linear, lumped-parameter, one-degree- of-freedom model that describes the first mode dynamic response of a piezoelectrically-actuated cantilevered beam. The original system consists of two identical, symmetrically disposed piezoelectric patch actuators bonded to a uniform beam with a tip mass. Specifically, the first mode of the system is described by an equivalent mass-spring-damper system where the equivalent mass, stiffness, damping, and force are functions of the parameters defining the piezoelectrically-actuated system. Experimental data is used to verify model damping and displacement. The model is then utilized to demonstrate that the dynamic response of the system depends upon four independent non-dimensional geometric variables. Numerical simulations are performed to graphically demonstrate this dependence and to indicate an optimal configuration for achieving a maximum deflection at the beam's free end during resonant excitation.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
An Institutional Approach to Chinese NGOs: State Alliance versus State Avoidance Resource Strategies

This article uses an institutional approach to examine Chinese NGOs as an emerging organizational field. In mature organizational fields, the organizations are powerfully constrained to follow the institutional practices of that field. However, in an emerging organizational field, the institutionalized constraints are not yet established, so actors can try out a wide range of practices. Some of these practices will become the new “rules of the game” of the organizational field when it is established. The content of these rules will shape the relationship between NGOs and the Chinese party-state for future generations. We find that a Chinese NGO's resource strategy is shaped by two interacting factors. First, NGOs operate in an evolving ecology of opportunity. Second, the social entrepreneurs who lead Chinese NGOs perceive that ecology of opportunity through the lens of their personal experiences, beliefs and expertise. As a result, the initial strategies of the organizations in our sample were strongly influenced by the institutional experience of their founders. Former state bureaucrats built NGOs around alliances with party-state agencies. In contrast, NGO founders that had no party-state experience usually avoided the state and sought areas away from government control/attention, such as the internet or private business.
Securities Transaction Tax and Market Efficiency: Evidence from the Japanese Experience

This study examines the effect of transaction costs on the time series behavior of stock returns over a period surrounding the April 1989 changes in tax rates on securities transactions and capital gains in Japan. We find significant decreases in estimates of the first-order autocorrelation in returns for Japanese stocks listed in Japan, but no changes for Japanese stocks dually listed in the United States as American Depository Receipts (ADRs), which were not subject to the tax law change. We also find lower price basis between the ADRs and their underlying Japanese stocks. These results are consistent with the hypothesis that a reduction in transaction costs improves the efficiency of the price discovery process.
Spectra of the Expansion Stage of X-Ray Bursts

We present an analytical theory of thermonuclear X-ray burst atmosphere structure. Newtonian gravity and diffusion approximation are assumed. Hydrodynamic and thermodynamic profiles are obtained as a numerical solution of the Cauchy problem for the first-order ordinary differential equation. We further elaborate a combined approach to the radiative transfer problem that yields the spectrum of the expansion stage of X-ray bursts in an analytical form in which Comptonization and free-free absorption-emission processes are accounted for and τ ~ r-2 opacity dependence is assumed. A relaxation method on an energy opacity grid is used to simulate a radiative diffusion process in order to match the analytical form of the spectrum, which contains the free parameter, to the energy axis. Numerical and analytical results show high similarity. All spectra consist of a power-law soft component and a diluted blackbody hard tail. We derive simple approximation formulae usable for mass-radius determination by observational spectra fitting.
Synthesis of Enantiopure N-tert-Butoxycarbonyl-2-aminocycloalkanones

Abstract A route to enantiomerically pure N-tert-butoxycarbonyl-2-aminocycloalkanones (ring size: 5-8 membered) from the corresponding cycloalkene oxides is described. The procedure involves (1) aminolysis with (S)-α-methylbenzylamine/Me3A1 and chromatographic separation of diastereomers, (2) hydrogenolysis to afford the trans-2-aminocycloalkanols, (3) tert-butoxycarbonyl (Boc) protection, and (4) PCC oxidation.
Empowering patients and strengthening communities for real health workforce and funding targets.

The setting of ambitious targets for expanding the health work force and improving its quality, efficiency and equitable service delivery is a task long overdue. It has been nearly one decade since the minimum needed density of physicians, nurses and skilled midwives – 2.28 workers per 1000 inhabitants – was established, but without attention to other health worker cadres. Furthermore, the estimate was based on only two areas of health worker activity – skilled birth attendance and measles immunization – that represent a minuscule fraction of people’s health-care needs. 1 As a result, it grossly underestimated the health workforce needed in low- and middle-income countries to respond effectively to the pandemics of human immunode ficiency virus infection (HIV), tuberculosis and malaria; the burden of neglected tropical diseases; unmet needs in child, maternal and sexual and reproductive health; and the growing prevalence of noncommunicable diseases. In addition to being unsuitable for responding to epidemiological trends and other contextual variables, the established worker density target was minimalistic and non-dynamic, for it conveyed the impression that meeting only the most rudimentary needs of health systems would suffice to alleviate the crisis in the area of human resources for health. No aspirational goals were set for progressively expanding and strengthening a health workforce to meet a population’s broad-spectrum health needs. Cometto & Witter 2 are correct in asserting that much has been learnt about the value of properly trained mid-level 3 and community health workers 4 in improving health service coverage and efficiency. Work is still being conducted to determine the best skill mixes and workforce ratios for different countries and to establish good practice models for health workforce training, task sharing and teamwork. Although simplification, combined with equity and quality, is the overall goal, the path is laborious given the headwinds of bureaucratic intransigence, chronic underfunding and persistent brain drain. To overcome these headwinds, it is crucial that health workers be paid living wages and given incentives to work in neglected areas. 5
The coming revolutions in particle physics.

Wonderful opportunities await particle physics over the next decade, with new instruments and experiments poised to explore the frontiers of high energy, infinitesimal distances, and exquisite rarity. We look forward to the Large Hadron Collider at CERN to explore the 1-TeV scale (extending efforts at LEP and the Tevatron to unravel the nature of electroweak symmetry breaking) and many initiatives to develop our understanding of the problem of identity: what makes a neutrino a neutrino and a top quark a top quark. We suspect that the detection of proton decay is only a few orders of magnitude away in sensitivity. Astronomical observations should help to tell us what kinds of matter and energy make up the universe. We might even learn to read experiment for clues about the dimensionality of spacetime. If we are inventive enough, we may be able to follow this rich menu with the physics opportunities offered by a linear electron-positron collider and a (muon storage ring) neutrino factory. I expect a remarkable flowering of experimental particle physics, and of theoretical physics that engages with experiment.
Chandra data processing: lessons learned and challenges met

Six years into the mission, Chandra data processing operations has reached a stage of maturity that allows nearly complete automation as well as dynamic flexibility to accommodate future changes in mission and instrument status and constraints. We present a summary of the procedural and technical solutions that have been developed since the launch of Chandra to meet unanticipated challenges in the area of data processing. Lessons learned concerning data processing are discussed, including an explanation of the source of each problem and the Chandra team's response to the problem. Potential pitfalls that might affect future projects are also included. The user interface, data quality screening, and quicklook software developed specifically to address issues identified after launch have proved valuable in meeting the goals of low-cost, efficient, and flexible mission operations for the Chandra mission and can provide insight for future mission designs.
Finite-difference time-domain simulation of spacetime cloak

In this work, we present a numerical method that remedies the instabilities of the conventional FDTD approach for solving Maxwell's equations in a space-time dependent magneto-electric medium with direct application to the simulation of the recently proposed spacetime cloak. We utilize a dual grid FDTD method overlapped in the time domain to provide a stable approach for the simulation of a magneto-electric medium with time and space varying permittivity, permeability and coupling coefficient. The developed method can be applied to explore other new physical possibilities offered by spacetime cloaking, metamaterials, and transformation optics.
Deprotonation of benzylic ethers using a hindered phosphazene base. A synthesis of benzofurans from ortho-substituted benzaldehydes.

The hindered nonionic phosphazene base P4-t-Bu efficiently deprotonates o-arylmethoxy benzaldehydes, leading to a direct synthesis of benzofurans. Strong ionic bases such as LDA, LiTMP, and KH failed.
Maneuver load control using optimized feedforward commands

A maneuver load control system has been designed for the Active Flexible Wing windtunnel model using constrained minimization optimization. Objectives of the controller were to limit total wing loads while maintaining constant roll performance. The load control was performed as a feedforward control utilizing the optimization solutions as table lookups. The tables were a function of the commanded roll acceleration and the current roll rate and output surface deflections. Test results confirmed predicted behavior, with time-to-90 degrees meeting scaled MIL-SPEC roll requirements. The controller was also integrated with multiple flutter suppression controllers and successfully flown beyond the flutter boundary, maintaining roll and load control performance.
The Characteristic Polynomial and Determinant Are Not Ad Hoc Constructions

polynomial of a matrix a as det(x I - a). We work in the opposite direction here.) For n-by-n matrices, we derive Jacobi's alternating sum formula for the determinant. We also recover the known ad hoc formulas for the determinant for quaternions and finitedimensional field extensions. Moreover, the product formula det(aa') = det(a) det(a') always holds.
Boundedly pivotal structural change tests in continuous updating GMM with strong, weak identification and completely unidentified cases

Abstract This paper develops structural change tests in the continuous updating GMM framework that are robust to weak identification. We propose likelihood ratio-like, Anderson–Rubin [1949. Estimation of the parameters of a single equation in a complete system of stochastic equations. Annals of Mathematical Statistics 20, 46–63], and Kleinbergen [2005. Testing parameters in GMM without assuming that they are identified. Manuscript. Brown University] types of tests. Since the limits of the test statistics are not nuisance parameter free, bounds for the limit of the test statistics are derived. The bounds are nuisance parameter free and robust to identification problems. Simulations show that the Anderson–Rubin (1949) and Kleinbergen [2005. Testing parameters in GMM without assuming that they are identified. Manuscript. Brown University] type of tests have very good small sample properties. In the case of weak instruments, the sup LM test of Andrews [1993a. Tests for parameter instability and structural change with unknown change point. Econometrica 61, 821–856] rejects the true null of parameter stability more than the nominal level, and, also has low power in the weak instrument setup.
Ag(I)-promoted Suzuki–Miyaura cross-couplings of n-alkylboronic acids

Abstract Ag(I) salts significantly enhance palladium-catalyzed Suzuki–Miyaura cross-couplings of n-alkylboronic acids with a wide variety of aryl and alkenyl halides/triflates.
Double extension regular algebras of type (14641)

Abstract We construct several families of Artin–Schelter regular algebras of global dimension four using double Ore extension and then prove that all these algebras are strongly noetherian, Auslander regular, Koszul and Cohen–Macaulay domains. Many regular algebras constructed in the paper are new and are not isomorphic to either a normal extension or an Ore extension of an Artin–Schelter regular algebra of global dimension three.
Evaluating monetary policy of the euro area with cross-country heterogeneity: Evidence from a New Keynesian model

Abstract This paper empirically investigates the optimal monetary policy conduct for the euro area in the presence of heterogeneous economic conditions across member states. Based on the New Keynesian monetary framework, we compare welfare losses under the assumption that the central bank conducts monetary policy using area-wide aggregate data against the alternative assumption that the central bank exploits country-specific as opposed to area-wide data. Empirical results reveal a sizable gain in stabilization performance if the European Central Bank formulates monetary policy by explicitly taking into account cross-country heterogeneity within the euro area. The estimated gain is more pronounced in a hybrid variant than in the purely forward-looking version of the New Keynesian model.
Modern methods of nucleic acid synthesis on polymeric supports

Abstract Deoxyoligonucleotides can be synthesized rapidly and in high yield because of recent advances in nucleic acid chemistry. Key innovations include solid phase synthesis of silica-based support and the development of stable deoxynucleoside phosphoramidites as synthons. When incorporated into manual, semiautomatic, or automatic instruments, these new procedures can be used to prepare probes, mixed probes, deoxyoligonucleotides for priming DNA synthesis, analogues of deoxyoligonucleotides, and genes. Oligoribonucleotides have also been prepared. The most successful approach so far developed involves using 2′-protected nucleosides as synthons and bis(diisopropylamino)methoxyphosphine as a phosphitylating reagent. A regioselective condensation route leading to the exclusive synthesis of 3′–5′ internucleotide linkages is possible.
Construction of Zero Autocorrelation Stochastic Waveforms

Stochastic waveforms are constructed whose expected autocorrelation can be made arbitrarily small outside the origin. These waveforms are unimodular and complex-valued. Waveforms with such spike like autocorrelation are desirable in waveform design and are particularly useful in areas of radar and communications. Both discrete and continuous waveforms with low expected autocorrelation are constructed. Further, in the discrete case, frames for Cd are constructed from these waveforms and the frame properties of such frames are studied.
Preparation of Diphenyl Phosphide and Substituted Phosphines using Alkali Metal in Silica Gel (M−SG)

Alkali metals absorbed in silica gel (the M-SG reagents) efficiently cleave C-P bonds in triaryl- and diarylphosphines. The resulting alkali metal phosphides can serve as useful building blocks for a variety of phosphines. Alkyldiarylphosphines undergo exclusive aryl group cleavage.
Optical Hamiltonians and symplectic twist maps

Abstract This paper concentrates on optical Hamiltonian systems of T∗ T n, i.e., those for which Hpp is a positive definite matrix, and their relationship with symplectic twist maps. We present theorems of decomposition by symplectic twist maps and existence of periodic orbits for these systems. The novelty of these results resides in the fact that no explicit asymptotic condition is imposed on the system.
The dynamical evolution of massive black hole binaries — II. Self-consistent N-body integrations

Abstract We use a hybrid N-body program to study the evolution of massive black hole binaries in the centers of galaxies, mainly to understand the factors affecting the binary eccentricity, the response of the galaxy to the binary merger, and the effect of loss-cone depletion on the merger time. The scattering experiments from paper I (Quinlan, 1996)[NewA, 1, 35] showed that the merger time is not sensitive to the eccentricity growth unless a binary forms with at least a moderate eccentricity. We find here that the eccentricity can become large under some conditions if a binary forms in a galaxy with a flat core or with a radial bias in its velocity distribution, especially if the dynamical friction is enhanced by resonances as suggested by Rauch & Tremaine (1996)[NewA, 1, 149]. But the necessary conditions seem unlikely, and our prediction from paper I remains unchanged: in most cases the eccentricity will start and remain small. The ejection of stars caused by the hardening of a binary may explain why large elliptical galaxies have weaker density cusps than smaller galaxies. If so, the central velocity distributions in those galaxies should have strong tangential anisotropies. The wandering of a binary from the center of a galaxy counteracts the effects of loss-cone depletion and helps the binary merge.
Stability of solutions of generalized logistic difference equations

then it is easily seen t ha t when 0 I. (II) k = i. ( I I I ) 0 < k < i. In section 2 we shall es tabl ish and prove three theorems which encompass three cases. For some re la ted results see [2] and [4]. For the difference equat ions of the general form:
Twinkling Phenomena in Snap-Through Oscillators

Oscillatory behavior in a chain of masses connected by springs with continuous but nonmonotonic spring forces can be induced under quasistatic loading. An insight into the birth of this behavior is obtained from a single mass system. A bifurcation study shows the potential for equilibrium jumps between multiple equilibria. As such, the transients occurring under quasistatic loading do not converge to the static loading case. Transients during dynamic loading show sensitivity to the loading parameters.
Parity and ruin in a stochastic game

We study an elementary two-player card game where in each round players compare cards and the holder of the card with the smaller value wins. Using the rate equations approach, we treat the stochastic version of the game in which cards are drawn randomly. We obtain an exact solution for arbitrary initial conditions. In general, the game approaches a steady state where the card value densities of the two players are proportional to each other. The leading small value behavior of the initial densities determines the corresponding proportionality constant, while the next correction governs the asymptotic time dependence. The relaxation toward the steady state exhibits a rich behavior, e.g., it may be algebraically slow or exponentially fast. Moreover, in ruin situations where one player eventually wins all cards, the game may even end in a finite time.
Novel methodologies for the synthesis of functionalized pyroglutamates

Alkylation of amino-acid derived iminoesters with Baylis–Hillman (BH) template based allyl bromides furnished α-methylene-β-substituted-pyroglutamates, while the corresponding alkylation with BH derived allylic acetates provided α-alkylidene-pyroglutamates. These methodologies have been applied in the synthesis of fused [3.2.0]-γ-lactam-β-lactones.
Toroidal and boundary-reducing Dehn fillings

Abstract Let M be a simple 3-manifold with a toral boundary component ∂ 0 M . If Dehn filling M along ∂ 0 M one way produces a toroidal manifold, and Dehn filling M along ∂ 0 M another way produces a boundary-reducible manifold, then we show that the absolute value of the intersection number on ∂ 0 M of the two filling slopes is at most two. In the special case that the boundary-reducing filling is actually a solid torus and the intersection number between the filling slopes is two, more is said to describe the toroidal filling.
Multicomputer processing in laboratory automation

Widespread availability of minicomputers in the scientific laboratory has become a reality in recent years. With the price and size reductions which have taken place, it is now practical to use these machines as routine tools in the laboratory environment. However, in order to effectively implement this new research tool the scientist has had to learn its limitations as well as its capabilities. It is well-known by computer scientists that, in general, the trade-off made by programmers is memory size vs. speed of execution. In other words, the more memory the programmer has available, the faster running program he may write and, conversely, the less memory he has, the slower will be the execution times. While there are a great many qualifications to this broad generalization, it still represents a recognizable truth.
Rock–paper–scissors and cycle-based games

Abstract The present work characterizes the unique Nash equilibrium for games that are based on a cyclic preference relation. In the Nash equilibrium of these games, each player randomizes between three specific actions. In particular, an alternative way of deriving the unique Nash equilibrium of the rock–paper–scissors game is proposed.
Storage optimization for large-scale distributed stream-processing systems

We consider storage in an extremely large-scale distributed computer system designed for stream processing applications. In such systems, both incoming data and intermediate results may need to be stored to enable analyses at unknown future times. The quantity of data of potential use would dominate even the largest storage system. Thus, a mechanism is needed to keep the data most likely to be used. One recently introduced approach is to employ retention value functions, which effectively assign each data object a value that changes over time in a prespecified way lDouglis et al.2004r. Storage space for data entering the system is reclaimed automatically by deleting data of the lowest current value. In such large systems, there will naturally be multiple file systems available, each with different properties. Choosing the right file system for a given incoming stream of data presents a challenge. In this article we provide a novel and effective scheme for optimizing the placement of data within a distributed storage subsystem employing retention value functions. The goal is to keep the data of highest overall value, while simultaneously balancing the read load to the file system. The key aspects of such a scheme are quite different from those that arise in traditional file assignment problems. We further motivate this optimization problem and describe a solution, comparing its performance to other reasonable schemes via simulation experiments.
Magnetic and electric field-induced enhancements in laser-induced anion formation

Abstract We report the first observation of magnetic and electric field-induced enhancements in anion formation from a laser-irradiated molecule. Enhanced anion formation in laser-excited benzene in the presence of electric and magnetic fields is reported. These enhancements are primarily due to the field-induced stabilization of the Rydberg states involved in the anion formation. When compared with magnetic fields, electric fields were found to contribute to a much lesser extent due to concurrent field ionization of high-lying Rydberg states.
Descending from on high: Lyman-series cascades and spin-kinetic temperature coupling in the 21-cm line

We examine the effect of Lyman-continuum photons on the 21-cm background in the high-redshift Universe. The brightness temperature of this transition is determined by the spin temperature T s , which describes the relative populations of the singlet and triplet hyperfine states. Once the first luminous sources appear, T s is set by the Wouthuysen-Field effect, in which Lyman-series photons mix the hyperfine levels. Here we consider coupling through n > 2 Lyman photons. We first show that coupling (and heating) from scattering of Lyn photons is negligible, because they rapidly cascade to lower-energy photons. These cascades can result in either a Lya photon - which will then affect Ts according to the usual Wouthuysen-Field mechanism - or photons from the 2 s → 1 s continuum, which escape without scattering. We show that a proper treatment of the cascades delays the onset of strong Wouthuysen-Field coupling and affects the power spectrum of brightness fluctuations when the overall coupling is still relatively weak (i.e., around the time of the first stars). Cascades damp fluctuations on small scales because only ∼1/3 of Lyn photons cascade through Lya, but they do not affect the large-scale power because that arises from those photons that redshift directly into the Lyα transition. We also comment on the utility of Lyn transitions in providing 'standard rulers' with which to study the high-redshift unvierse.
Magnetic shielding of nuclei in molecules

Abstract An expression is developed for the magnetic field at a nucleus of a poly-atomic molecule with zero resultant orbital and spin angular momenta in an external magnetic field. The field at the nucleus is not the same as the externally applied field because of the field arising from the motion of the electrons in the molecule. The expression for the electron contribution to the magnetic field is shown to consist of two parts. The first is a simple term that is similar to the diamagnetic correction developed by Lamb for atoms. The second is a complicated one arising from second order paramagnetism and is analogous to the term dependent on the high frequency matrix elements in the theory of molecular diamagnetism. Under certain circumstances the second order paramagnetism term could become quite large. Since both of these terms are altered when the same nucleus is in different molecules, they at least partially and perhaps completely explain the chemical effect in nuclear moment measurements that has been reported by various observers. For linear molecules, the second order paramagnetism term is shown to be directly related to the experimentally measurable spin-rotational magnetic interaction constant of the molecule. This relation is particularly valuable in the important case of molecular hydrogen where it is shown that the correction for second order paramagnetism is −0.56 × 10−5. When this is added to the Lamb type term as calculated by Anderson, the total magnetic shielding constant for molecular H2 becomes 2.68 × 10−5
The role of solvent viscosity in the dynamics of protein conformational changes

Nanosecond lasers were used to measure the rate of conformational changes in myoglobin after ligand dissociation at ambient temperatures. At low solvent viscosities the rate is independent of viscosity, but at high viscosities it depends on approximately the inverse first power of the viscosity. Kramers theory for unimolecular rate processes can be used to explain this result if the friction term is modified to include protein as well as solvent friction. The theory and experiment suggest that the dominant factor in markedly reducing the rate of conformational changes in myoglobin at low temperatures (less than 200 K) is the very high viscosity (greater than 10(7) centipoise) of the glycerol-water solvent. That is, at low temperatures conformational substates may not be "frozen" so much as "stuck."
Survival benefit of extended D2 resection for proximal gastric cancer

Background The long-term survival of patients with adenocarcinoma of the proximal stomach remains dismal. Despite its increasing frequency and poor prognosis, a general consensus has not been reached on the extent of surgical resection. The significance of extended lymph node dissection (D2 gastrectomy) for the surgical treatment of patients with proximal gastric cancer was evaluated. Methods Sixty-two patients who underwent a potentially curative total or proximal gastric resection were retrospectively divided by extent of lymphadenectomy into two groups: the extended resection group (D2,D2.5) and limited resection group (D1,D1.5). Survival rates were estimated by the method of Kaplan and Meier [J Am Stat Assoc 53:457-486, 1958] and the differences compared by the log rank test. Multivariate analysis of prognostic parameters was performed using the Cox proportional hazard model. Results The median overall survival time for the extended resection group (D2,D2.5) was 34 months compared to 18 months for patients treated by a more limited resection (D1,D1.5). Patients treated with extended resection had an estimated 5-year overall survival rate of 37% compared to 21% for patients treated with limited resection. This difference was statistically significant with a P value of 0.04. The median disease-free interval for the extended resection group was 31 months compared to 17.6 months for patients in the limited resection group. The 5 year disease-free survival rate for both groups was 37% and 17%, respectively (P = 0.09). Extent of lymphadenectomy and stage of disease were found to be independent predictors of overall and cancer-free survival. Conclusions Patients treated with an extended lymph node dissection (D2 gastrectomy) were more likely to survive 5 years, had longer disease-free intervals, and prolonged median survival times (particularly patients with T1-3,N0-1,M0 cancers) as compared to those patients treated with a more limited lymph node dissection (D1,D1.5). These differences reached or approached statistical significance.
Theresa Marie Schiavo's Long Road to Peace

The death of Theresa Marie Schiavo came about only after almost 7 years of argument among her family members. Her husband, Michael Schiavo, was convinced that she would have refused the medically supplied nutrition and hydration maintaining her life. Her parents, Robert and Mary Schindler, and her siblings were equally convinced that her condition was not so hopeless that she would have chosen to refuse treatment. The result was a bitter battle reaching through state and federal court systems, legislatures, and chief executives' offices. This article provides introductory factual background for the articles that discuss the Schiavo case in this special issue of Death Studies.
Equity Impacts and Challenges of Highway Access Management in an Emerging Economy: South Africa at the Crossroads

As a middle-income country, South Africa realizes that it cannot build its way out of every transportation challenge that it faces. Alternative interventions have a role to play in optimizing the efficiency of the present transportation network while ensuring that the benefits from this optimization are distributed equitably. The implementation of the proposed Guidelines on Road Access Management in South Africa is one such intervention that may equitably improve the transportation environment. This paper describes the evolution and status quo of access management in South Africa, assesses the concept and purpose of access management from an equity perspective, considers the efficacy of implementing national access management guidelines while honoring the equity principles contained in the South African constitution and other civil laws and regulations, and assesses a selection of access management techniques with respect to their potential equity impacts. The paper identifies a selection of obstacles tha...
Near-Infrared Spectroscopy of TW Hya: A Revised Spectral Type and Comparison with Magnetospheric Accretion Models

We present high signal-to-noise ratio (S/N), moderate spectral resolution (R ~ 2000-2500) near-infrared (0.8-5.0 μm) spectroscopy of the nearby T Tauri star TW Hya. By comparing the spectrum and the equivalent widths of several atomic and molecular features with those for stars in the IRTF near-infrared library, we revise the spectral type to M2.5V, which is later than what is usually adopted (K7V). This implies a substantially cooler stellar temperature than previously assumed. Comparison with various pre-main-sequence models suggests that TW Hya is only ~3 Myr old, much younger than the usually adopted 8-10 Myr. Analysis of the relative strengths of the H lines seen in the spectrum yields estimates for the temperature and density of the emitting region of Te ≥ 7500 K and ne ~ 1012-1013 cm–3. The thickness of the emitting region is 102-104 km and the covering fraction is f * ~ 0.04. Our derived physical parameter values agree with the predictions of the magnetospheric accretion scenario. The highest S/N H lines have profiles that indicate multiple emission components. We derive an excess spectrum (above that of the M2.5V template) that peaks in the H band. Although our derived veiling values (~0.1) agree with previous estimates, the excess spectrum does not match that of current models in which this flux is generated by an inner optically thin disk. We suggest that the excess flux spectrum instead reflects the differences in atmospheric opacity, gravity, and age between TW Hya and older, higher gravity, field M2.5 dwarfs.
Globalization and Inequality: Explaining American Exceptionalism.

Globalization creates pressure for greater inequality throughout the world, but these pressures are expressed more fully in the United States than in other developed nations. Although the distribution of US income before taxes is no more unequal than other nations, after taxes it is considerably less egalitarian. This occurs because of specific institutional arrangements that fail to redistribute income effectively and allow the pressures of globalization to be fully realized. These arrangements represent a shift from the past and were deliberately enacted over the past two decades with divergent consequences for those at the top and bottom of the socioeconomic hierarchy. The realignment of the US political economy can ultimately be traced to America’s legacy of racism. Once leaders in the Democratic party sought to include African Americans in the benefits of Roosevelt’s New Deal, support for economic populism evaporated in the middle and working classes. The advantage of the wealth is further enhanced by a political system in which those with money are better able to have their interests served legislatively than the poor or working classes.
A limit to the X-ray luminosity of nearby normal galaxies

The hypothesis that normal galaxies are on the average more luminous in the X-ray region than the Milky Way galaxy or M31 and therefore are possible candidates for the low-luminosity sources of the 2 to 60 keV extragalactic diffuse background is tested. Data from the A-2 detectors on the HEAO-1 spacecraft were examined for emission from positions coincident with 76 selected normal galaxies, and upper limits to the average galactic luminosity for various luminosity distributions resulting in the observed count rate distribution were determined. For uniform and exponential galactic luminosity distributions, limits of 2.7 x 10 to the 38th erg/sec and 3.4 x 10 to the 38th erg/sec, respectively, at the 90% confidence level were obtained. It is shown that the Hubble-constant-independent upper limit to galactic emissivity is less than 1% of the diffuse background emissivity, indicating that normal galaxies are not responsible for the diffuse X-ray background and have luminosities comparable to that of the Galaxy.
Interaction of a spherical acoustic wave with an elastic spherical shell

Abstract The interaction of a spherical acoustic wave with an elastic spherical shell is treated analytically. The solution includes the coupling between the acoustic sound field and vibration of the shell with any degree of fluid loading. The formulation for the far-field acoustic pressure is derived in terms of natural spherical wave functions, the properties of the acoustic medium, and the material constants of the shell. The far acoustic field is computed for a thin aluminum shell and several sound source locations over a large range of ka, where k is the wavenumber, and a is the shell radius. It is shown that the acoustic pressure depends significantly on whether the shell is in air or is submerged in water, particularly when the sound source is very near the surface. In air, the sound field of the shell is nearly identical to that of a rigid sphere but, in water, the shell is more compliant, which results in a damped radiation field that is characterized by vibrational resonances throughout the range of frequencies considered. As the sound sources is moved further away from the surface, however, this resonance response decreases very rapidly, and the sound field corresponds more closely to that of the shell in air.
On the zone theorem for hyperplane arrangements

The zone theorem for an arrangement of n hyperplanes in d-dimensional real space says that the total number of faces bounding the cells intersected by another hyperplane is O(nd−1). This result is the basis of a time-optimal incremental algorithm that constructs a hyperplane arrangement and has a host of other algorithmic and combinatorial applications. Unfortunately, the original proof of the zone theorem, for d ≥ 3, turned out to contain a serious and irreparable error. This paper presents a new proof of the theorem. Our proof is based on an inductive argument, which also applies in the case of pseudo-hyperplane arrangements. We also briefly discuss the fallacies of the old proof along with some ways of partially saving that approach.
An overview of sugar-modified oligonucleotides for antisense therapeutics

Among the multitude of chemical modifications that have been described over the past two decades, oligonucleotide analogs that are modified at the 2'-position of the furanose sugar have been especially useful for improving the drug-like properties of antisense oligonucleotides (ASOs). These modifications bias the sugar pucker towards the 3'-endo-conformation and improve ASO affinity for its biological target (i.e., mRNA). In addition, antisense drugs incorporating 2'-modified nucleotides exhibit enhanced metabolic stability, and improved pharmacokinetic and toxicological properties. Further conformational restriction of the 2'-substituent to the 4'-position of the furanose ring yielded the 2',4'-bridged nucleic acid (BNA) analogs. ASOs containing BNA modifications showed unprecedented increase in binding affinity for target RNA, while also improved nuclease resistance, in vitro and in vivo potency. Several ASO drug candidates containing 2'-modified nucleotides have entered clinical trials and continue to make progress in the clinic for a variety of therapeutic indications.