cssi/SciSciGPT-SciSciNet huggingface dataset:
On the Determination of N and O Abundances in Low Metallicity Systems

We show that in order to minimize the uncertainties in the N and O abundances of low-mass, low-metallicity (O/H ≤ 1/5 solar) emission-line galaxies, it is necessary to employ separate parameterizations for inferring Te(N+) and Te(O+) from Te(O+2). In addition, we show that for the above systems, the ionization correction factor (ICF) for obtaining N/O from N+/O+, where the latter is derived from optical emission-line flux ratios, is = 1.08 ± 0.09. These findings are based on state-of-the-art single-star H II region simulations, employing our own modeled stellar spectra as input. Our models offer the advantage of having matching stellar and nebular abundances. In addition, they have O/H as low as 1/50 solar (lower than any past work), as well as log(N/O) and log(C/O) fixed at characteristic values of -1.46 and -0.7, respectively. The above results were used to rederive N and O abundances for a sample of 68 systems with 12 + log(O/H) ≤ 8.1, whose dereddened emission-line strengths were collected from the literature. The analysis of the log(N/O) versus 12 + log(O/H) diagram of the above systems shows that (1) the largest group of objects forms the well-known N/O plateau with a value for the mean (and its statistical error) of -1.43, (2) the objects are distributed within a range in log(N/O) of -1.54 to -1.27 in Gaussian fashion around the mean with a standard deviation of σ = , and (3) a χ2 analysis suggests that only a small amount of the observed scatter in log(N/O) is intrinsic.
Weakly democratic regular tax equilibria in a local public goods economy with perfect consumer mobility

In this paper we study the existence of equilibria in a local public goods economy which has the following structure. There are a finite number of geographical regions. Each region has a government which provides public goods locally by buying private goods inputs on competitive markets and transforming these inputs into outputs of public goods by using a convex technology. The local public goods are pure in the sense that all the local residents consume the total produced, with no spillovers to other regions. Each regional government raises revenue from the residents of its region to cover the costs of the public goods it provides. The local governments are assumed to be weakly democratic in the sense that no public sector proposal (that is, a vector of public good provisions and a tax scheme to pay for it) will be enacted for which there exists an alternative proposal which is unanimously preferred by the local residents. (Note that it is not being assumed that unanimity is a necessary condition for a public sector proposal to be enacted.) Private goods are produced by price-taking, profit maximizing producers using convex technologies, and are traded across regions. A continuum of price-taking, utility maximizing consumers, who are perfectly mobile across regions, treat parametrically the public sector proposals of the various local governments in deciding where to live. There are a finite number of different types of consumers, with type defined by a consumer’s preferences, initial endowments, and share of private sector profits. A feasible allocation is a specification of a partition of the consumers among the regions, a vector of technically feasible public good provisions (and an associated vector of private good inputs used in its production) for
Bank holding company diversification and production efficiency

Bank Holding Companies (BHCs) have been diversifying their businesses increasingly among banking, securities and insurance activities in the recent decades through establishment of Section 20 subsidiaries in earlier years and through formation of financial holding companies after the Gramm–Leach–Bliley Act (GLBA, 1999). This study examines whether BHC diversification is associated with improvement or detriment in its production efficiency. We apply the Data Envelopment Analysis (DEA) to calculate the Malmquist index of productivity, and the total factor productivity change for a sample of BHCs over the period 1997–2007. Two main results are obtained. First, technical efficiency is negatively associated with activity diversification and the effect is primarily driven by BHCs that did not experience diversification through Section 20 subsidiaries. Second, the degree of change in diversification over time is not associated with total factor productivity change but it is negatively associated with technical e...
Mirror symmetry in three-dimensional gauge theories, quivers and D-branes

We construct and analyze dual N = 4 supersymmetric gauge theories in three dimensions with unitary and symplectic gauge groups. The gauge groups and the field content of the theories are encoded in quiver diagrams. The duality exchanges the Coulomb and Higgs branches and the Fayet-Iliopoulos and mass parameters. We analyze the classical and the quantum moduli spaces of the theories and construct an explicit mirror map between the mass parameters and the Fayet-Iliopoulos parameters of the dual. The results generalize the relation between ALE spaces and moduli spaces of SU(n) and SO(2n) instantons. We interpret some of these results from the string theory viewpoint, for SU(n) by analyzing T-duality and extremal transitions in type II string compactifications, for SO(2n) by using D-branes as probes. Finally, we make a proposal for the moduli space of vacua of these theories in the absence of matter.
Timing Analysis of the Light Curve of the Dipping-Bursting X-Ray Binary X1916–053

We present the timing analysis results for our observations of the X-ray dip source X1916-053 conducted with RXTE between February and October of 1996. Our goal was to finally measure the binary period—as either the X-ray dip period or the ~1% longer optical modulation period—thereby establishing whether the binary has a precessing disk (SU UMa model) or a third star (triple model). Combined with historical data (1979-1996), the X-ray dip period is measured to be 3000.6508 ± 0.0009 s with a 2 σ upper limit || ≤ 2.06 × 10-11. From our quasi-simultaneous optical observations (1996 May 14-23) and historical data (1987-1996), we measure the optical modulation period to be 3027.5510 ± 0.0052 s with a 2 σ upper limit || ≤ 2.28 × 10-10. The two periods are therefore each stable (over all recorded data) and require a 3.9087 ± 0.0008 day beat period. This beat period, and several of its harmonics, is also observed as variations in the dip shape. Phase modulation of X-ray dips, observed in a 10 consecutive day observation, is highly correlated with the ~3.9 day dip shape modulation. The 1987-1996 optical observations show that the optical phase fluctuations are a factor of 3 larger than those in the X-ray. We discuss SU UMa versus triple models to describe the X1916-053 light-curve behavior and conclude that the X-ray dip period, with smaller phase jitter, is probably the binary period, so that the required precession is most likely similar to that observed in SU UMa and X-ray nova systems. However, the "precession" period stability, and especially the fact that the times of X-ray bursts may partially cluster to occur just after X-ray dips, continues to suggest that this system may be a hierarchical triple.
Automated Cloud Tracking Using Precisely Aligned Digital ATS Pictures

The measurement of winds to an accuracy of at least 2 knots (1 m/s) is a major requirement of the global atmospheric research program (GARP) [1]. Such accurate wind measurements will be needed over large regions presently lacking ground or rawinsonde observations. A man-computer system called WINDCO has been developed to measure cloud motion from ATS pictures. This system is capable of providing cloud motion measurements that are repeatable to within 6 knots over two independent time intervals in the majority of cases.
Alcohol use trajectories after high school graduation among emerging adults with type 1 diabetes.

Abstract Objective To explore alcohol involvement trajectories and associated factors during the year post-high school (HS) graduation among emerging adults with type 1 diabetes. Methods Youth (N = 181) self-reported alcohol use at baseline and every 3 months for 1 year post-HS graduation. Data were also collected on parent–youth conflict, diabetes self-efficacy, major life events, living and educational situations, diabetes management, marijuana use, cigarette smoking, and glycemic control. Trajectories of alcohol use were modeled using latent class growth analysis. Associations between trajectory class and specific salient variables were examined using analysis of variance, chi square, or generalized linear mixed model, as appropriate. Results Identified alcohol involvement trajectory classes were labeled as (1) consistent involvement group (n = 25, 13.8%) with stable, high use relative to other groups over the 12 months; (2) growing involvement group (n = 55, 30.4%) with increasing use throughout the 12 months; and (3) minimal involvement group (n = 101, 55.8%) with essentially no involvement until the ninth month. Those with minimal involvement had the best diabetes management and better diabetes self-efficacy than those with consistent involvement. In comparison with those minimally involved, those with growing involvement were more likely to live independently of parents; those consistently involved had more major life events; and both the growing and consistent involvement groups were more likely to have tried marijuana and cigarettes. Conclusions This sample of emerging adults with type 1 diabetes has three unique patterns of alcohol use during the first year after HS.
Minimalist and universal peptidomimetics

Many “new generation” peptidomimetics are designed to present amino acid side chains only; they do not have structural features that resemble peptide main chains. These types of molecules have frequently been presented in the literature as mimics of specific secondary structures. However, many “side-chain only” peptidomimetics do notrest in single conformational states, but exist in a limited number of freely interconverting forms. These different conformations may resemble different secondary structures, so referring to them as, for instance, turn- or helical-mimics understates the ways they could adapt to various binding situations. Sets of scaffolds that can be used to mimic aspects of nearly every secondary structure, i.e. universal peptidomimetics, can be constructed. These may assume a privileged place in library design, particularly in high throughput screening for pharmacological probes for which binding conformations, or even the target itself, is unknown at the time the library is designed (critical review, 101 references).
Analysis of MDI High-Degree Mode Frequencies and their Rotational Splittings

We present a detailed analysis of solar acoustic mode frequencies and their rotational splittings for modes with degree up to 900. They were obtained by applying spherical harmonic decomposition to full-disk solar images observed by the Michelson Doppler Imager onboard the Solar and Heliospheric Observatory spacecraft. Global helioseismology analysis of high-degree modes is complicated by the fact that the individual modes cannot be isolated, which has limited so far the use of high-degree data for structure inversion of the near-surface layers (r>0.97R ⊙). In this work, we took great care to recover the actual mode characteristics using a physically motivated model which included a complete leakage matrix. We included in our analysis the following instrumental characteristics: the correct instantaneous image scale, the radial and non-radial image distortions, the effective position angle of the solar rotation axis, and a correction to the Carrington elements. We also present variations of the mode frequencies caused by the solar activity cycle. We have analyzed seven observational periods from 1999 to 2005 and correlated their frequency shift with four different solar indices. The frequency shift scaled by the relative mode inertia is a function of frequency alone and follows a simple power law, where the exponent obtained for the p modes is twice the value obtained for the f modes. The different solar indices present the same result.
Definability in dynamic logic

Abstract We study the expressive power of various versions of Dynamic Logic and compare them with each other as well as with standard languages in the logical literature. One version of Dynamic Logic is equivalent to the infinitary logic L ω 1, ω CK but regular Dynamic Logic is strictly less expressive. In particular, the ordinals ω ω and ω ω ·2 are indistinguishable by formulas of regular Dynamic Logic. We also study the effects of including array assignments and/or random assignments on the expressive power of Dynamic Logic.
Hot Ion Plasma Heating Experiments in SUMMA

Initial empirical results are presented for the hot-ion plasma heating experiments conducted in the new SUMMA (Superconducting Magnetic Mirror Apparatus) at NASA Lewis Research Center. A discharge was formed by applying a radially inward DC electric field near the mirror throats. Data were obtained at midplane magnetic flux densities from 1.0 to 3.5 tesla. Charge-exchange neutral particle energy analyzer data were reduced to ion temperatures using a plasma model that included a Maxwellian energy distribution super-imposed on an azimuthal drift, finite ion orbits, and radial variations in density and electric field. Using this plasma model, the highest ion temperatures computed were 5 keV, 1.2 keV, and 1 keV for He+, H2+, and H+, respectively. These were obtained at a mid-plane magnetic flux density of 1.6 T. Ion temperature was found to scale roughly as (P/B)n, where P/B is the ratio of power input to magnetic flux density and n is about 1 for hydrogen and 2 for helium. Optical spectroscopy line-broadening measurements yielded ion temperatures about 15 percent higher than the charge-exchange neutral particle analyzer results for hydrogen and about 50 percent higher for helium. Spectroscopically obtained electron temperatures ranged from 3 to 30 eV.
Asymmetric synthesis of the hydroxylamino sugar of calicheamicin

Abstract A stereochemically general procedure for the conversion of 2,3-epoxyalcohols to N -alkoxy oxazolidinones via the DBU promoted cyclizations of 2,3-epoxy- N -alkoxyurethanes has been developed and applied to the first asymmetric synthesis of the calicheamicin hydroxylamino sugar, 7 .
LABORATORY ASTROPHYSICS EXPERIMENTS IN X-RAY TRANSFER PHYSICS RELEVANT TO COSMIC ACCRETION-POWERED SOURCES

The interpretation of upcoming cosmic soft X-ray spectroscopic observations may require a vast improvement in the state of our knowledge of basic atomic physics and radiation transfer processes, particularly for the important class of accretion-powered systems such as cataclysmic variables, X-ray binaries, and active galactic nuclei. For these sources, short wavelength spectral features are formed in the transfer of X-radiation from a powerful central source outward through a cooler, surrounding medium. The line emitting gas is photoionized and the level populations are determined largely by recombination cascades and photoexcitation as opposed to collisional effects. These processes can be rather complex and many uncertainties remain. We are developing a new approach to this problem using time-resolved studies of laser produced plasmas. Experiments which are currently underway include the measurements of : (a) inner and outer shell photoabsorption cross-sections of intermediate ions of abundant elements, and (b) fluorescent excitation processes due to wavelength coincidences of resonant transitions from different ions. In connection with this program, we have developed a novel reflection grating spectrometer coupled to a streak camera which provides high resolution spectra at soft X-ray and EUV wavelengths at the sub-nanosecond level .We describe our laboratory facility and some of our preliminary experimental results.
Oxidative and nonoxidative formation of internucleotide linkages

Abstract Activation of nucleoside 3′-hydrogenphosphonodithioates with iodine in the presence of nucleosides and amines yields dinucleoside phosphorodithioates and nucleoside phosphorodithioamidates, respectively. Similar activation of nucleoside 3′-methylphosphonothioates yields dinucleoside methylphosphonothioates.
The effective pressure of a saturated gluon plasma

Abstract The evolution of the gluon plasma produced with saturation initial conditions is calculated via transport theory for nuclear collisions with 0.1 s TeV. The effective longitudinal pressure is found to remain significantly below the lattice QCD pressure with these initial conditions until the plasma cools to near the confinement scale. The absolute value of the transverse energy per unit of rapidity and its dependence on beam energy is shown to provide a sensitive test of gluon saturation models since the fractional transverse energy loss due to final state interactions is predicted to be much smaller and exhibit a weaker energy dependence than nondissipative hydrodynamics applied throughout the evolution.
Animal Magnetism and Curriculum History

This article elaborates the impact that crises of authority provoked by animal magnetism, mesmerism, and hypnosis in the 19th century had for field formation in American education. Four layers of analysis elucidate how curriculum history’s repetitive focus on public school policy and classroom practice became possible. First, the article surveys external conditions of possibility for the enactment of compulsory public schooling. Second, “internal” conditions of possibility for the formation of educational objects (e.g., types of children) are documented via the processes of differance that were generated from within the experiences of confinement. Third, the article maps how these were interpenetrated by animal magnetic debates that were lustered and planished in education’s emerging field, including impact upon behavior management practices, the contouring of expertise and authority, the role of Will in intelligence testing and child development theories, and the redefinition of public and private. Last, the article examines implications for curriculum history, whether policy- or practice-oriented, especially around the question of influence, the theorization of child mind, and philosophies of Being.
Neutron vibrational spectroscopy: The use of hydrogen as a structural and dynamical probe

The large incoherent scattering cross-section of hydrogen combined with an exact knowledge of the form of the scattering function can be utilized in neutron spectroscopic experiments to study local structural environments as well as interaction strengths. An important application of this technique is to focus on a particular hydrogen atom, or hydrogenous molecular group in the material, mainly by employing isotopic substition. Hydrogen is thereby used as a local probe of structure as well as dynamics. Examples include: site geometry and occupancy in metal hydrides, potential well geometry of hydrogen-metal complexes and hydrogen-bonded systems, and dynamical coupling in linear chain hydrogen-bonded materials.
Isotope Effect in Intermetallic Diffusion

Ten measurements of the isotope effict for diffusion of Fe/sup 55/ and Fe/sup 59/ in pure single cryatals of silver and copper were made over approximately a 300 deg C temperature interval below the melting point. The measured isotope effect was found to be about 2/3, significantly less than the value of unity expected from conventional reaction rate theory. It is shown from Vineyard's extension of reaction rate theory that the measured isotope effect is to a good approximation a product of the Bardeen-Herring correlation factor and the fraction of the total translational kinetic energy associated with the diffusing tracer in a tracervacancy exchange. It is shown that the ring, interstitialcy, crowdion, and relaxion mechanisms are not responsible for diffusion in the systems studied. The three-frequency theory of correlation for vacancy diffusion in fcc lattices is extended to show that the relative frequency factors are vacancy exchange. It is shown that the ring, interstitialcy, crowdion, and relaxion mechanisms are not responsible for diffusion in the systems studied. The three-frequency completely specified by a knowledge of the correlation factor and the diffusion coefficients. An expression for the difference in the Arrhenius Q and the activation energy due to the temperature dependencemore » of the correlation factor is derived. This theory is shown to be inconsistent with the observed isotope effect if many-body effects are neglected. It is shown that a "long-range" repulsive interaction between the vacancy and impurity would be necessary if the measured isotope effect is to be explained purely in terms of correlation. (auth)« less
Group transfer addition reactions of selenomalononitriles to chiral enol ethers. Asymmetric radical addition and selenium transfer reactions

Abstract Group transfer addition reactions of alkyl phenylselenomalononitriles to enol ethers derived from trans-2-phenylcyclohexanol and 8-phenylmenthol occur cleanly, and moderate to excellent stereoselection is observed in both the radical addition and phenylselenium transfer steps.
Hydrothermal Synthesis of Carbonate-Free Strontium Zirconate: Thermodynamic Modeling and Experimental Verification

A comprehensive thermodynamic model has been applied to predict the optimum conditions for the hydrothermal synthesis of phase-pure strontium zirconate. The model is based on the accurate knowledge of standard-state thermochemical properties of all species and a realistic activity coefficient model. The predictions are conveniently summarized in the form of phase stability and yield diagrams. Unlike our previous works, the diagrams are automatically generated using newly developed software, which makes it possible to analyze the effect of reactant identity and concentrations, contaminants, pH, and temperature as independent variables. The calculations revealed a high sensitivity of the synthesis to the identity of Sr precursors, Sr/Zr molar ratio of starting materials, and temperature as well as to the contamination with carbonates. The predictions have been confirmed experimentally at two temperatures (433 and 473 K) using strontium hydroxide or strontium nitrate as sources of Sr and a hydrous zirconium ...
Enantioselective addition of diethylzinc to aldehydes catalyzed by a β-amino alcohol derived from (+)-3-carene

A (+)-3-carene derived aminoalcohol was successfully used as a chiral ligand in the catalytic enantioselective diethylzinc addition to various aldehydes. Very high enantiomeric excess (up 98% in 1-(2-methoxyphenyl)-1-propanol) was obtained. A plausible mechanism has been suggested for the observed enantioselectivity.
A High-Eccentricity Low-Mass Companion to HD 89744.

HD 89744 is an F7 V star with a mass of 1.4 M middle dot in circle, an effective temperature of 6166 K, an age of 2.0 Gyr, and metallicity sFesHs=0.18. The radial velocity of the star has been monitored with the Advanced Fiber-Optic Echelle spectrograph at the Whipple Observatory since 1996, and evidence has been found for a low-mass companion. The data were complemented by additional data from the Hamilton spectrograph at Lick Observatory during the companion's periastron passage in the fall of 1999. As a result, we have determined the star's orbital wobble to have a period P=256 days, an orbital amplitude K=257 m s-1, and an eccentricity e=0.7. From the stellar mass, we infer that the companion has a minimum mass m2sini=7.2 MJ in an orbit with a semimajor axis a2=0.88 AU. The eccentricity of the orbit, among the highest known for extrasolar planets, continues the trend that extrasolar planets with semimajor axes greater than about 0.15 AU tend to have much higher eccentricities than are found in our solar system. The high metallicity of the parent star reinforces the trend that parent stars of extrasolar planets tend to have high metallicity.
A global map of Mars' crustal magnetic field based on electron reflectometry

[1] We present a global map of the amplitude of Mars' crustal magnetic field at 170-km altitude based on electron reflectometry, using data from the Magnetometer/Electron Reflectometer (MAG/ER) experiment on board Mars Global Surveyor. This new map contains features that are about seven times weaker than those in previously published maps obtained with the MAG alone from the 400-km-altitude mapping orbit. The increased sensitivity and nearly complete sampling reveal numerous weak magnetic sources in the northern lowlands. A group of these sources forms a nearly complete ring surrounding the Utopia basin, coinciding with a ridge of thickened crust. A larger 5800-km-diameter ring is defined by a ∼120° arc of magnetic sources that extend to the north pole, supporting the hypothesis that part of the dichotomy boundary was established or modified by the Utopia impact. We also map the magnetic signatures of the Hellas, Argyre, and Isidis impact basins with increased dynamic range, confirming the large contrast in magnetic field strength between the basin interior and surroundings. Magnetic sources surround most of the Tharsis rise, except in the north, suggesting that the construction of Tharsis thermally demagnetized a large region of the northern lowlands. Thermal demagnetization is also suggested in the Elysium region, which intersects the inner Utopia magnetic ring, and south of the Hellas basin in the vicinity of Peneus Patera and Amphitrites Patera.
Design and synthesis of metal-organic frameworks using metal-organic polyhedra as supermolecular building blocks.

This critical review highlights supermolecular building blocks (SBBs) in the context of their impact upon the design, synthesis, and structure of metal–organic materials (MOMs). MOMs, also known as coordination polymers, hybrid inorganic–organic materials, and metal–organic frameworks, represent an emerging class of materials that have attracted the imagination of solid-state chemists because MOMs combine unprecedented levels of porosity with a range of other functional properties that occur through the metal moiety and/or the organic ligand. First generation MOMs exploited the geometry of metal ions or secondary building units (SBUs), small metal clusters that mimic polygons, for the generation of MOMs. In this critical review we examine the recent (<5 years) adoption of much larger scale metal–organic polyhedra (MOPs) as SBBs for the construction of MOMs by highlighting how the large size and high symmetry of such SBBs can afford improved control over the topology of the resulting MOM and a new level of scale to the resulting framework (204 references).
PRESENT AND FUTURE OF CENTRAL PRODUCTION WITH STAR DETECTOR AT RHIC

The present status and future physics program of Central Production using the STAR detector at RHIC will be described. The program focuses on particle production resulting from the Double Pomeron Exchange (DPE) process. Forward protons from the DPE interaction are detected in the Roman Pot system installed at 55.5 m and 58.5 m on both sides of the STAR interaction point. The recoil system of charged particles from the DPE process is measured in the STAR Time Projection Chamber (TPC). The first data were taken in 2009 during the RHIC-Run 9 using polarized proton-proton collisions at . The preliminary spectra of two pion and four pion invariant mass reconstructed by STAR TPC in central region of pseudo-rapidity |η| < 1, are presented. Plans to take data with the current system at and plans to upgrade the forward proton tagging system, so that it can reach higher masses and obtain large data samples in searching for glueballs that could be produced in the DPE process, are also discussed.
Strategic Trading and Welfare in a Dynamic Market

This paper studies a dynamic model of a financial market with N strategic agents. Agents receive random stock endowments at each period and trade to share dividend risk. Endowments are the only private information in the model. We find that agents trade slowly even when the time between trades goes to 0. In fact, welfare loss due to strategic behaviour increases as the time between trades decreases. In the limit when the time between trades goes to 0, welfare loss is of order 1/N, and not 1/N2 as in the static models of the double auctions literature. The model is very tractable and closed-form solutions are obtained in a special case.
29 November 2011 stellar occultation by 2060 Chiron: Symmetric jet-like features

On 29 November 2011 UT, 2060 Chiron occulted a R = 14.9-mag star; data were successfully obtained at the 3-m NASA Infrared Telescope Facility (IRTF) on Mauna Kea and 2-m Las Cumbres Observatory Global Telescope Network (LCOGT) Faulkes Telescope North (FTN) at Haleakala. The MORIS lightcurve shows a solid-body detection of Chiron’s nucleus with a chord duration of 16.0±1.4 s, corresponding to a chord length of 158±14 km. Symmetric, dual extinction features in the FTN light curve indicate the presence of optically thick material roughly 300 km from the body midpoint. The duration of the features indicates a 3±2 km feature separated by 10–14 km from a second 7±2 km feature. The symmetry, optical thickness, and narrow size of these features allow for the intriguing possibility of a near-circular arc or shell of material.
The width of the Theta+ exotic baryon in the chiral soliton model

In 1997 Diakonov, Petrov, and Polyakov, calculated the width of the exotic baryon that they called $\Theta^{ + }$ . The prediction, $\Gamma(\Theta^{ + })\lesssim 15$ MeV, has received considerable attention, especially in light of the narrowness of the experimentally reported $\Theta^{ + }$ resonance. However, there is an arithmetic error in their work: when corrected, the width estimate quoted in that paper should have been $\lesssim 30$ MeV.
Formation, Reactivity, and Properties of Nondative Late Transition Metal–Oxygen and–Nitrogen Bonds

Complexes containing bonds between heteroatoms such as nitrogen and oxygen and "late" transition metals (i.e., those located on the right side of the transition series) have been implicated as reactive intermediates in numerous important catalytic systems. Despite this, Our understanding of such M-X linkages still lags behind that of their M-H and M-C analogues. New synthetic strategies have now made possible the isolation and study of a variety of monomeric late-metal alkoxide, aryloxide, and amide complexes, including parent hydroxide and amide species. The heteroatoms in these materials form surprisingly strong bonds to their metal centers, and their bond energies do not necessarily correlate with the energies of the corresponding H-X bonds. The M-X complexes typically exhibit nucleophilic reactivity, in some cases form strong hydrogen bonds to proton donors, and even deprotonate relatively weak acids. These observations, as well as thermodynamic investigations, suggest that late metal - heteroatom bonds are strongly polarized and possess significant ionic character, properties that play an important role in their interactions with organic compounds.
Discovery of the arsenic isotopes

Twenty-nine arsenic isotopes have been observed so far and the discovery of these isotopes is discussed here. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.
Locally Biased Galaxy Formation and Large-Scale Structure

We examine the influence of the morphology-density relation and a wide range of simple models for biased galaxy formation on statistical measures of large-scale structure. We contrast the behavior of local biasing models, in which the efficiency of galaxy formation is determined by the density, geometry, or velocity dispersion of the local mass distribution, with that of nonlocal biasing models, in which galaxy formation is modulated coherently over scales larger than the galaxy correlation length. If morphological segregation of galaxies is governed by a local morphology-density relation, then the correlation function of E/S0 galaxies should be steeper and stronger than that of spiral galaxies on small scales, as observed, while on large scales the E/S0 and spiral galaxies should have correlation functions with the same shape but different amplitudes. Similarly, all of our local bias models produce scale-independent amplification of the correlation function and power spectrum in the linear and mildly nonlinear regimes; only a nonlocal biasing mechanism can alter the shape of the power spectrum on large scales. Moments of the biased galaxy distribution retain the hierarchical pattern of the mass moments, but biasing alters the values and scale dependence of the hierarchical amplitudes S3 and S4. Pair-weighted moments of the galaxy velocity distribution are sensitive to the details of the bias prescription even if galaxies have the same local velocity distribution as the underlying dark matter. The nonlinearity of the relation between galaxy density and mass density depends on the biasing prescription and the smoothing scale, and the scatter in this relation is a useful diagnostic of the physical parameters that determine the bias. While the assumption that galaxy formation is governed by local physics leads to some important simplifications on large scales, even local biasing is a multifaceted phenomenon whose impact cannot be described by a single parameter or function. The sensitivity of galaxy clustering statistics to the details of galaxy biasing is an obstacle to testing cosmological models, but it is an equally significant asset for testing physical theories of galaxy formation against data from redshift and peculiar velocity surveys.
Observability, controllability and local reducibility of linear codes on graphs

This paper is concerned with the local reducibility properties of linear realizations of codes on finite graphs. Trimness and properness are dual properties of constraint codes. A linear realization is locally reducible if any constraint code is not both trim and proper. On a finite cycle-free graph, a linear realization is minimal if and only if every constraint code is both trim and proper. A linear realization is called observable if it is one-to-one, and controllable if all constraints are independent. Observability and controllability are dual properties. An unobservable or uncontrollable realization is locally reducible. A parity-check realization is uncontrollable if and only if it has redundant parity checks. A tail-biting trellis realization is uncontrollable if and only if its trajectories partition into disconnected subrealizations. General graphical realizations do not share this property.
The Relationship between Innovation and Market Share: Evidence from the Global LCD Industry

We investigate the impact of technological capability on firm market share using technology investment data in the global thin-film-transistor liquid-crystal-display panel industry from 1999 to 2007. The Arellano–Bond estimation of the dynamic panel model indicates that prior technological capability is positively correlated with current market share. The magnitude of this effect appears economically substantial: an improvement of technological capability by one standard deviation implied a permanent increase of 2.6 percent-point in quarterly market share, a return tantamount to $470 million in 2007 sales. The Granger test reveals that technological capability helps to predict future market share, but that the inverse is not true.
An Introduction to Modern Astrophysics

An Introduction to Modern Astrophysics is a comprehensive, well-organized and engaging text covering every major area of modern astrophysics, from the solar system and stellar astronomy to galactic and extragalactic astrophysics, and cosmology. Designed to provide students with a working knowledge of modern astrophysics, this textbook is suitable for astronomy and physics majors who have had a first-year introductory physics course with calculus. Featuring a brief summary of the main scientific discoveries that have led to our current understanding of the universe; worked examples to facilitate the understanding of the concepts presented in the book; end-of-chapter problems to practice the skills acquired; and computational exercises to numerically model astronomical systems, the second edition of An Introduction to Modern Astrophysics is the go-to textbook for learning the core astrophysics curriculum as well as the many advances in the field.
Preparation of novel azabicyclic amines and α7 nicotinic acetylcholine receptor activity of derived aryl amides

Three new azabicyclic amines, namely exo-3-amino-1-azabicyclo[3.2.1]octane, 3-amino-1-azabicyclo-[3.2.2]nonane and exo-6-amino-8-azabicyclo[3.2.1]octane, have been designed and prepared as isosteres of 3-aminoquinuclidine. Aryl amides derived from each series were prepared and tested in an α7 nicotinic acetylcholine receptor assay as part of a drug discovery program to treat the cognitive deficits in schizophrenia. All new amides showed significant α7 nAChR activity and one series displayed potent α7 activity equal to the quinuclidine series.
Enhancement of electron spin echo envelope modulation spectroscopic methods to investigate the secondary structure of membrane proteins.

This paper reports on a significant improvement of a new structural biology approach designed to probe the secondary structure of membrane proteins using the pulsed EPR technique of electron spin e...
Economic Incentives, Natural Resources and Conflict in Africa

This paper reviews how rebel leaders motivate followers to fight in wars in Sub-Saharan Africa. Almost all rebel leaders do use economic incentives, but they also avail themselves of other strategies to motivate their soldiers, including political indoctrination, ethnic mobilisation and coercion. The type of incentive employed will depend primarily on the nature of the state confronted. In particular, those movements that face competent national militaries will have to evolve into viable armies while rebels fighting states that are weak and corrupt can afford to lead movements that employ coercion and pursue economic agendas.
Enterprise integration in e-government

This paper investigates the e-government architecture issue as a means of addressing the interoperability gap. It will incorporate the new knowledge acquired in the e-government integration methodology of the interconnectivity of cross-layers. These layers include the vertical direction of strategy, business, process, service and information. Enterprise architecture mainly mediates between business and IT to minimise the gap by improving governance, agility and business integrity. All of these disciplines and principles should be applied to attain e-government transformation.
What is paratransit worth

Paratransit is a flexible demand-responsive form of public transportation intended for transporting mobility impaired individuals. This is the first study that estimates both demand and cost functions for publicly provided paratransit in the United States and the first to conduct a benefit-cost analysis for this mode. We find that the benefits of paratransit far exceed its associated costs. The results suggest that paratransit riders have few transportation alternatives available to them. We also find that the level of service matters in the demand for paratransit.
Spectral Geometry and Asymptotically Conic Convergence

In this paper we define asymptotically conic convergence in which a family of smooth Riemannian metrics degenerates to have an isolated conic singularity. For a conic metric (M0,g0) and an asymptotically conic (scattering) metric (Z,gz) we define a nonstandard blowup, the resolution blowup, in which the conic singularity in M0 is resolved by Z. Equivalently, the resolution blowup resolves the boundary of the scattering metric using the conic metric; the resolution space is a smooth compact manifold. This blowup induces a smooth family of metrics {g } on the compact resolution space M, and we say (M,g ) converges asymptotically conically to (M0,g0) as ! 0. Let and 0 be geometric Laplacians on (M,g ) and (M0,g0), respectively. Our first result is convergence of the spectrum of to the spectrum of 0 as ! 0. Note that this result implies spectral convergence for the k-form Laplacian under certain geometric hypotheses. This theorem is proven using rescaling arguments, standard elliptic techniques, and the b-calculus of [26]. Our second result is technical: we construct a parameter ( ) dependent heat operator calculus which contains, and hence describes precisely, the heat kernel for as ! 0. The consequences of this result include: the existence of a polyhomogeneous asymptotic expansion for H as ! 0, with uniform convergence down to t = 0. To prove this result we construct manifolds with corners (heat spaces) using both standard and non-standard blowups, on which we construct corresponding heat operator calculi. A parametrix construction modeled after the heat kernel construction of [26] and a maximum principle type argument complete this proof.
Theoretical study of the in-plane components of the 13C shielding tensors in condensed aromatic hydrocarbons

The Pople model for chemical shielding is applied to calculate the in-plane components of the 13C shielding tensors of condensed aromatic hydrocarbons. The wave functions are evaluated using the MNDO method and the calculated results are supported by the very good agreement with the experimental results in the few cases in which experimental information is available.
Video testing in modern television systems

The measurement of picture quality has been high on the list of television engineering priorities since video compression became a practical reality. This paper examines the modern television system outlining its elements and the appropriate levels of testing. The need for continuation of traditional analog and digital testing methods is emphasized as a prerequisite for both effective video compression and the measurement of resulting pictures. Proposed picture quality measurement methods and possible limitations of their application are discussed.
Quasi-particle re-summation and integral gap equation in thermal field theory

A new approach to quantum field theory at finite temperature and density in arbitrary space-time dimension D is developed. We focus mainly on relativistic theories, but the approach applies to non-relativistic ones as well. In this quasi-particle re-summation, the free energy takes the free-field form but with the one-particle energy ?() replaced by ?(), the latter satisfying a temperature-dependent integral equation with kernel related to a zero temperature form-factor of the trace of stress-energy tensor. For 2D integrable theories the approach reduces to the thermodynamic Bethe ansatz. For relativistic theories, a thermal c-function Cqs(T) is defined for any D based on the coefficient of the black body radiation formula. Thermodynamical constraints on it's flow are presented, showing that it can violate a ``c-theorem'' even in 2D. At a fixed point Cqs is a function of thermal gap parameters which generalizes Roger's dilogarithm to higher dimensions. This points to a strategy for classifying rational theories based on ``polylogarithmic ladders'' in mathematics, and many examples are worked out. Other applications are discussed, including the free energy of anyons in 2D and 3D, phase transitions with a chemical potential, and the equation of state for cosmological dark energy. For the latter we show that ?1 < w < ?1/3.
Impact of gate assignment on gate-holding departure control strategies

Gate holding reduces congestion by reducing the number of aircraft present on the airport surface at any time, while not starving the runway. Because some departing flights are held at gates, there is a possibility that arriving flights cannot access the gates and have to wait until the gates are cleared. This is called a gate conflict. Robust gate assignment is an assignment that minimizes gate conflicts by assigning gates to aircraft to maximize the time gap between two consecutive flights at the same gate; it makes gate assignment robust, but passengers may walk longer to transfer flights. In order to simulate the airport departure process, a queuing model is introduced. The model is calibrated and validated with actual data from New York La Guardia Airport (LGA). Then, the model simulates the airport departure process with the original gate assignment and a robust gate assignment to assess the impact of gate assignment on gate-holding departure control. The results show that the robust gate assignment reduces the number of gate conflicts caused by gate holding compared to the original gate assignment. Therefore, robust gate assignment can be combined with gate-holding departure control to improve operations at congested airports with limited gate resources.
Parameter estimation for fractional Ornstein–Uhlenbeck processes

Abstract We study a least squares estimator θ T for the Ornstein–Uhlenbeck process, d X t = θ X t d t + σ d B t H , driven by fractional Brownian motion B H with Hurst parameter H ≥ 1 2 . We prove the strong consistence of θ T (the almost surely convergence of θ T to the true parameter θ ). We also obtain the rate of this convergence when 1 / 2 ≤ H 3 / 4 , applying a central limit theorem for multiple Wiener integrals. This least squares estimator can be used to study other more simulation friendly estimators such as the estimator θ T obtained by a function of ∫ 0 T X t 2 d t .
NEW BASE-ALTERED ADENOSINE ANALOGUES: SYNTHESIS AND AFFINITY AT ADENOSINE A1 and A2A RECEPTORS.

N6-Substituted adenosine analogues containing cyclic hydrazines or chiral hydroxy (ar)alkyl groups, designed to interact with the S2 and S3 receptor subregions, have been synthesized and their binding to the adenosine A1 and A2A receptors have been investigated. Examples of both types of compounds were found to exhibit highly selective binding (Ki in low nM range) to the rat A1 receptor.
Dark excitons due to direct Coulomb interactions in silicon quantum dots

Electron-hole exchange interactions can lead to spin-forbidden ''dark'' excitons in direct-gap quantum dots. Here, we explore an alternative mechanism for creating optically forbidden excitons. In a large spherical quantum dot made of a diamond-structure semiconductor, the symmetry of the valence band maximum (VBM) is t{sub 2}. The symmetry of the conduction band minimum (CBM) in direct-gap material is a{sub 1}, but for indirect-gap systems the symmetry could be (depending on size) a{sub 1}, e, or t{sub 2}. In the latter cases, the resulting manifold of excitonic states contains several symmetries derived from the symmetries of the VBM and CBM (e.g., t{sub 2}xt{sub 2}=A{sub 1}+E+T{sub 1}+T{sub 2} or t{sub 2}xe=T{sub 1}+T{sub 2}). Only the T{sub 2} exciton is optically active or ''bright,'' while the others A{sub 1}, E, and T{sub 1} are ''dark.'' The question is which is lower in energy, the dark or bright. Using pseudopotential calculations of the single-particle states of Si quantum dots and a direct evaluation of the screened electron-hole Coulomb interaction, we find that, when the CBM symmetry is t{sub 2}, the direct electron-hole Coulomb interaction lowers the energy of the dark excitons relative to the bright T{sub 2} exciton. Thus, the lowest energy exciton ismore » forbidden, even without an electron-hole exchange interaction. We find that our dark-bright excitonic splitting agrees well with experimental data of Calcott et al., Kovalev et al., and Brongersma et al. Our excitonic transition energies agree well with the recent experiment of Wolkin et al. In addition, and contradicting simplified models, we find that Coulomb correlations are more important for small dots than for intermediate sized ones. We describe the full excitonic spectrum of Si quantum dots by using a many-body expansion that includes both Coulomb and exchange electron hole terms. We present the predicted excitonic spectra. (c) 2000 The American Physical Society.« less