cssi/SciSciGPT-SciSciNet huggingface dataset:
Equality of opportunity in educational achievement in the Middle East and North Africa

This paper is an empirical investigation of inequality of education opportunities in the Middle East and North Africa (MENA). We use student scores from tests administered by the international consortium Trends in Mathematics and Science Study (TIMSS) for a number of MENA countries and over time since 1999 to estimate the effect of circumstances children are born into on their academic achievement in science and mathematics. We find that inequality of opportunities explains a significant part of the inequality in educational achievements in most MENA countries, but there is ample heterogeneity. Family background variables are the most important determinants of inequality in achievement, followed by community characteristics. The results show that, despite great efforts in past decades to invest in free public education, most MENA countries are less opportunity equal in educational achievement than European countries, and several are less so than Latin America and the United States. From the variation in inequality of education opportunities across countries and over time we draw lessons on the influence of different education systems or changes in policy on equality of opportunity.
Effects of viscosity on transonic-aerodynamic and aeroelastic characteristics of oscillating airfoils

Studies were made to investigate the effects of viscosity on aerodynamic and aeroelastic characteristics of oscillating airfoils. The computer code LTRAN2 (viscous), which is based on a small disturbance aerodynamic theory, was used to make aerodynamic computations. Two viscous models, the viscous-ramp model and the lag-entrainment model were considered. The unsteady viscous effects were obtained by use of the quasi-steady assumptions. Two cases, a conventional airfoil, NACA 64A010, and a supercritical airfoil, MBB-A3, were studied at Mach numbers 0.796 and 0.7557, respectively. For both the airfoils, steady and unsteady aerodynamic computations were made by using inviscid and viscous theories. The steady and the unsteady results for the NACA 64A010 airfoil and the steady results for the MBB-A3 airfoil were compared with the available wind-tunnel results. Flutter speeds were computed for both airfoils by using the U-g method and the effects of viscosity on the airfoils were studied. Results from the viscous methods show improvements over the inviscid method.
Deposition, Structure, and Properties of Cermet Thin Films Composed of Ag and Y‐Stabilized Zirconia

This paper reports that Ag{sub 1{minus}x}((Y{sub 2}O{sub 3}){sub 0.1}(ZrO{sub 2}){sub 0.9}){sub x} (YSZ) cermet thin films have been deposited by reactive magnetron cosputtering from Ag and Zr/Y targets in Ar-O{sub 2} mixtures. The deposition conditions were such that the YSZ component in the films was fully oxidized. The film densities varied from {approx}75% to {gt}85% as the total pressure was decreased from 20 to 5 mTorr. Film resistivities {rho} varied with Ag volume fraction f{sub Ag} from 5 {times} 10{sup {minus}6} {Omega}-cm to {gt}10{sup 9} {Omega}-cm. For f{sub Ag} {lt} 0.4, {rho} decreased rapidly with increasing f{sub Ag}. For f{sub Ag} {gt} 0.4, {rho} decreased more gradually with increasing f{sub Ag}. {rho} in annealed films ranged from 4 {times} 10{sup {minus}4} {Omega}-cm for f{sub Ag} = 0.4 to 5 {times} 10{sup {minus}6} {Omega}-cm for pure Ag. Long term ({gt}100 h) annealing at {ge}700{degrees} C resulted in a gradual increase in cermet resistivity due to Ag evaporation and Ag segregation to surface islands. Both decomposition mechanisms were effectively suppressed due to Ag evaporation and Ag segregation to surface islands. Both decomposition mechanisms were effectively suppressed at up to 750{degrees} C by depositing a 1 {mu}m thick porous perovskite cap layer onmore » the cermet. Complex impedance spectroscopy measurements in air of cermet electrodes on YSZ electrolytes gave interfacial resistances that were a factor of {approx}6 lower than those of pure AG electrodes, e.g., 1.4 {Omega}-cm{sup 2} at 750{degrees} C. Ag-YSZ cermets thus have potential as high-conductivity, low-overpotential air electrode materials for solid-oxide electrochemical devices operating at temperatures {le}750{degrees}C.« less
Development of a quasi-monoenergetic 6 MeV Gamma Facility at NASA Goddard Space Flight Center

Abstract The 6 MeV Gamma Facility has been developed at NASA Goddard Space Flight Center (GSFC) to allow in-house characterization and testing of a wide range of gamma-ray instruments such as pixelated CdZnTe detectors for planetary science and Compton and pair-production imaging telescopes for astrophysics. The 6 MeV Gamma Facility utilizes a circulating flow of water irradiated by 14 MeV neutrons to produce gamma rays via neutron capture on oxygen ( 16 O(n,p) 16 N→ 16 O⁎→ 16 O+γ). The facility provides a low cost, in-house source of 2.742, 6.129 and 7.117 MeV gamma rays, near the lower energy range of most accelerators and well above the 2.614 MeV line from the 228 Th decay chain, the highest energy gamma ray available from a natural radionuclide. The 7.13 s half-life of the 16 N decay allows the water to be irradiated on one side of a large granite block and pumped to the opposite side to decay. Separating the irradiation and decay regions allows for shielding material, the granite block, to be placed between them, thus reducing the low-energy gamma-ray continuum. Comparison between high purity germanium (HPGe) spectra from the facility and a manufactured source, 238 Pu/ 13 C, shows that the low-energy continuum from the facility is reduced by a factor ∼30 and the gamma-ray rate is ∼100 times higher at 6.129 MeV.
Curvature Coordinates in Cosmology

We develop cosmological theory from first principles starting with curvature coordinates ($R$,$T$) in terms of which the metric has the form $d{s}^{2}(R,T)=\frac{d{R}^{2}}{A(R,T)}+{R}^{2}d{\ensuremath{\Omega}}^{2}\ensuremath{-}B(R,T)d{T}^{2}$. The Einstein field equations, including cosmological constant, are given for arbitrary ${T}_{\ensuremath{\nu}}^{\ensuremath{\mu}}$, and the timelike geodesic equations are solved for radial motion. We then show how to replace $T$ with a new time coordinate $\ensuremath{\tau}$ that is equal to the time measured by radially moving geodesic clocks. Cosmology is brought into the picture by setting ${T}_{\ensuremath{\nu}}^{\ensuremath{\mu}}$ equal to the stress-energy tensor for a perfect fluid composed of geodesic particles, and letting $\ensuremath{\tau}$ be the time measured by clocks coincident with the fluid particles. We solve the field equations in terms of ($R$,$\ensuremath{\tau}$) coordinates to get the metric coefficients in terms of the pressure and density of the fluid. The metric on the subspace $\ensuremath{\tau}=\mathrm{const}$ is equal to $d{R}^{2}+{R}^{2}d{\ensuremath{\Omega}}^{2}$, and so is flat, with $R$ having the physical significance that it is a measure of proper distance in this subspace. As specific examples, we consider the de Sitter and Einstein---de Sitter universes. On an ($R$,$\ensuremath{\tau}$) spacetime diagram, all trajectories in an Einstein---de Sitter universe are emitted from $R=0$ at the "big bang" at $\ensuremath{\tau}=0$. Further, a light signal coming toward $R=0$ at some time $\ensuremath{\tau}g0$ will, in its past history, have started from $R=0$ at $\ensuremath{\tau}=0$, and have turned around on the line $2R=3\ensuremath{\tau}$. A consequence of this is a "tilting" of the null cones along the trajectory of a cosmological particle. The turnaround line $2R=3\ensuremath{\tau}$ marks the transition where an $R=\mathrm{const}$ line changes from spacelike to timelike in character. We show how to apply the techniques developed here to the inhomogeneous problem of a Schwarzschild mass imbedded in a given universe in the paper immediately following this one.
System of systems engineering

The purpose of this article is to develop the concept, foundations, research directions, and practice implications for System of Systems Engineering (SoSE). First, we introduce the nature of the co...
An alternative route for the preparation of α,α-difluoropropargylphosphonates

Abstract The organometallic reagent, (EtO) 2 P(O)CF 2 ZnBr, reacts with 1-bromoalkynes in the presence of CuBr to give good yields (50–61%) of α,α-difluoropropargylphosphonates.
An updated cost study for enhanced sludge washing of radioactive waste

This article updates previous cost savings studies conducted to evaluate the use of enhanced sludge washing (ESW) of high-level radioactive waste at the United States Department of Energy Hanford Site. The cost savings estimate was updated using stochastic analysis based on new information from the Independent Review of Hanford High Level Waste Volume and the more recent Tank Waste Remediation System Operation and Utilization Plan. It is estimated that implementation of ESW in the tank waste remediation system (TWRS) at the Hanford Site can save approximately $4.8 billion compared to the use of an alternative, simpler water wash. The simpler water wash dissolution was found to be 85 percent as effective as the ESW dissolution. Further, the updated remediation cost estimate of $4.8 billion savings is uncertain only within ±$1.6 billion at the 95 percent confidence interval. © 2003 Wiley Periodicals, Inc. Reprinted from Remediation Volume 12, Number 2.
MCRs reshaped into a switchable microwave-assisted protocol toward 5-aminoimidazoles and dihydrotriazines.

A tunable microwave-assisted protocol for the synthesis of two biologically relevant families of heterocycles has been designed. Via a simple switch of reaction conditions, the same starting materials can be engaged in either an improved synthesis of the dihydrotriazine scaffold or a novel, first-in-class MCR to render the challenging 5-aminoimidazole nucleus in a single step. An additional first-in-class MCR is also reported utilizing guanidines to afford 2,5-aminoimidazoles.
A memoryless, stochastic mechanism of timing of phases of behavior by a neural network controller

For a sensorimotor network to generate adaptive behavior in the environment, the phases of the behavior must be appropriately timed. When the behavior is driven simply by the sensory stimuli from the environment, these can supply the timing. But when the behavior is driven by an internal "goal" that ignores and perhaps even opposes the immediate sensory stimuli, the timing must be generated internally by the network. We have modeled a realistic behavioral scenario that requires such internal timing.
ALGEBRAIC APPROACH TO THE 1=N EXPANSION IN QUANTUM FIELD THEORY

The 1/N expansion in quantum field theory is formulated within an algebraic framework. For a scalar field taking values in the N by N hermitian matrices, we rigorously construct the gauge invariant interacting quantum field operators in the sense of power series in 1/N and the 't Hooft coupling parameter as members of an abstract *-algebra. The key advantages of our algebraic formulation over the usual formulation of the 1/N expansion in terms of Green's functions are (i) that it is completely local so that infrared divergencies in massless theories are avoided on the algebraic level and (ii) that it admits a generalization to quantum field theories on globally hypberbolic Lorentzian curved spacetimes. We expect that our constructions are also applicable in models possessing local gauge invariance such as Yang–Mills theories. The 1/N expansion of the renormalization group flow is constructed on the algebraic level via a family of *-isomorphisms between the algebras of interacting field observables corresponding to different scales. We also consider k-parameter deformations of the interacting field algebras that arise from reducing the symmetry group of the model to a diagonal subgroup with k factors. These parameters smoothly interpolate between situations of different symmetry.
A Solution for Lightly Loaded Adhesive Rough Surfaces With Application to MEMS

The stiction forces that exist in microelectromechanical systems (MEMS) are characterized by surface energy and surface roughness. To simulate this contact condition, a three-dimensional fractal surface geometry and an adhesive contact model for a single asperity are used together to create a numerical adhesive rough surface solution methodology. This novel method of solution determines the characteristic adhesive contact type for each individual asperity uniquely at the time of load and area integration. Such a simulation more accurately represents the physics of the asperity-based contact. Numerical results for the adherence force are presented as a function of surface topography, interface compliance, and the work of adhesion for a MEMS interface. The magnitude of the force required to separate an adhesive rough surface interface is given in relation to a polysilicon system.
Instantons and fixed-point actions in SU(2) gauge theory

Abstract We describe the properties of instantons in lattice gauge theory when the action is a fixed-point action of some renormalization group transformation. We present a theoretically consistent method for measuring topological charge using an inverse renormalization group transformation. We show that, using a fixed-point action, the action of smooth configurations with non-zero topological charge is greater than or equal to its continuum value 8π2/π2.
ULTRA-HIGH ENERGY COSMIC RAYS

We describe the current status of the High Resolution Fly's Eye detector. Recent results indicate that the UHE cosmic ray spectrum exhibits significant structure near 1019 eV. A few events are seen beyond 1020 eV in contradiction to the AGASA ground array claim of no cut-off. The composition of the cosmic rays is found to change from a predominantly heavy to a predominantly light mixture between and 1017 and 1018 eV. No evidence for anisotropy, on either small scales or large scales is found, in contradiction to AGASA. Systematic errors and absolute energy scale issues are now being carefully considered to see how to partially resolve this discrepancy. A new experiment(FLASH) at the Stanford Linear Accelerator Center (SLAC) to measure the Nitrogen fluorescence efficiency more precisely is described.
Connectivity of h -complexes

This paper verifies a conjecture of Edelman and Reiner regarding the homology of the h-complex of a Boolean algebra. A discrete Morse function with no low-dimensional critical cells is constructed, implying a lower bound on connectivity. This together with an Alexander duality result of Edelman and Reiner implies homology vanishing also in high dimensions. Finally, possible generalizations to certain classes of supersolvable lattices are suggested.
Compatibility of the Thioamide Functional Group with β-Sheet Secondary Structure: Incorporation of a Thioamide Linkage into a β-Hairpin Peptide

We report the incorporation of a thioamide linkage between the i + 2 and i + 3 residues of the type II‘ β-turn of a peptide known to fold into a β-hairpin conformation. Two-dimensional NMR spectroscopy and circular dichroism spectroscopy indicate that the thioxo peptide adopts a hairpin conformation similar to that of the oxo peptide and that the hairpin conformation persists at elevated temperatures. The results show that a thioamide linkage is compatible with β-sheet secondary structure.
Generation of Pure Phase NMR Subspectra for Measurement of Homonuclear Coupling Constants

Recently it has been demonstrated that dramatic spectral simplification can be obtained by editing a regular ‘H NMR spectrum into a set of subspectra by means of the one-dimensional HOHAHA experiment (I). As pointed out earlier, scalar couplings are difficult to measure from such a spectrum because of phase and intensity distortions of the muhiplet components in the various subspectra. Here, it is demonstrated that pure phase subspectra can be obtained readily by combination of the 1D HOHAHA experiment with the z-filtering technique (2). Guidelines for minimizing the number of T averages, needed for the z filter, are also presented. If the Zeeman term from the Hamiltonian is eliminated, the spin system will evolve solely under the influence of scalar couplings. Braunschweiler and Ernst (3) lirst utilized this concept in isotropic liquids for generating total coherence transfer (TOCSY) 2D spectra of spin systems of coupled protons. A number of more efficient mixing schemes based on the same mechanism have since been reported (1, 4, 5). We prefer to use the so-called MLEV- 17 sequence (4) for mixing because it covers a substantial bandwidth (kO.3~) and because it is relatively insensitive to exact phase shifting or pulse width adjustment. Moreover, this mixing scheme lengthens the apparent Tip (4, 5) so that less signal is lost during this mixing period relative to other mixing schemes. To record pure phase spectra, Braunschweiler and Ernst proposed cc&ding a number of spectra, recorded with different mixing times. This procedure works satisfactorily when few spins are involved in a J-coupled network. For larger spin systems however, this procedure is not perfect because the magnetization transfer appears to lose its oscillatory character, i.e., the oscillation is overdamped. Consequently, the spectra obtained are not 100% absorptive and measurement of scalar couplings may lead to errors. Moreover, in a large network of coupled spins (alkaloids, steroids, etc.) averaging over a number of mixing times, some of which would have to be quite long, gives a subspectrum of nearly the entire molecule and therefore defeats the purpose of the experiment. As demonstrated here, the z-filtering technique, proposed by Slarensen
Robustness analysis of digital feedback control systems with time-varying sampling periods

In the present paper, we study robustness properties of a class of digital feedback control systems with time-varying sampling periods consisting of an interconnection of a continuous-time nonlinear plant (described by systems of first-order ordinary differential equations), a nonlinear digital controller (described by systems of first-order ordinary difference equations), and appropriate interface elements between the plant and controller (A/D and D/A converters). For such systems, we establish results for exponential stability of an equilibrium (in the Lyapunov sense) in the presence of vanishing perturbations and for the boundedness of solutions (i.e., Lagrange stability) under the influence of nonvanishing perturbations. We apply these results in the study of quantization effects.
The Role of Galactic Winds on Molecular Gas Emission from Galaxy Mergers

Galactic winds from starbursts and active galactic nuclei (AGNs) are thought to play an important role in driving galaxies along the starburst-AGN sequence. Here, we assess the impact of these winds on the CO emission from galaxy mergers and, in particular, search for signatures of starburst and AGN-feedback-driven winds in the simulated CO morphologies and emission-line profiles. We do so by combining a three-dimensional non-LTE molecular line radiative transfer code with smoothed particle hydrodynamic (SPH) simulations of galaxy mergers that include prescriptions for star formation, black hole growth, a multiphase interstellar medium (ISM), and the winds associated with star formation and black hole growth. Our main results are (1) Galactic winds can drive outflows of masses ~108-109 M☉ which may be imaged via CO emission-line mapping. (2) AGN-feedback-driven winds are able to drive detectable CO outflows for longer periods of time than starburst-driven winds owing to the greater amount of energy imparted to the ISM by AGN feedback compared to star formation. (3) Galactic winds can control the spatial extent of the CO emission in postmerger galaxies, and may serve as a physical motivation for the subkiloparsec scale CO emission radii observed in local advanced mergers. (4) Secondary emission peaks at velocities greater than the circular velocity are seen in the CO emission lines in all models, regardless of the associated wind model. In models with winds, however, these high-velocity peaks are seen to preferentially correspond to outflowing gas entrained in winds, which is not the case in the model without winds. The high-velocity peaks seen in models without winds are typically confined to velocity offsets (from the systemic) 1.7 times the circular velocity, whereas the models with AGN-feedback-driven winds can drive high-velocity peaks to ~2.5 times the circular velocity.
Modal content of noise generated by a coaxial jet in a pipe

Noise generated by air flow through a coaxial obstruction in a long, straight pipe was investigated with concentration on the modal characteristics of the noise field inside the pipe and downstream of the restriction. Two measurement techniques were developed for separation of the noise into the acoustic duct modes. The instantaneous mode separation technique uses four microphones, equally spaced in the circumferential direction, at the same axial location. The time-averaged mode separation technique uses three microphones mounted at the same axial location. A matrix operation on time-averaged data produces the modal pressure levels. This technique requires the restrictive assumption that the acoustic modes are uncorrelated with each other. The measured modal pressure spectra were converted to modal power spectra and integrated over the frequency range 200-6000 Hz. The acoustic efficiency levels (acoustic power normalized by jet kinetic energy flow), when plotted vs. jet Mach number, showed a strong dependence on the ratio of restriction diameter to pipe diameter. The acoustic energy flow analyses based on the thermodynamic energy equation and on the results of Mohring both resulted in orthogonality properties for the eigenfunctions of the radial mode shape equation. These orthogonality relationships involve the eigenvalues and derivatives of the radial mode shape functions.
Reasoning with geometric information in digital space

Concurrency requires consistency and correctness. Isothetic rectangles can be used as a geometrical technique to verify a safe and deadlock free schedule for concurrent nodes. However, the known algorithms for concurrency using isothetic rectangles require the prior knowledge of the system behavior. We provide a new mechanism to use isothetic rectangles without this limitation. The discrete nature of isothetic rectangles provides an opportunity for inter-diagrammatic reasoning. Inter-Diagrammatic Reasoning (IDR) can be easily computed on a parallel machine, and has a complexity of O(n) for most of the iso-rectangles problems where the best known algorithm was O(nlogn) in Euclidean geometry. This new framework will also allow dynamic mode of operation in calculating the closure of a set of iso-rectangles; rather than restricting the solution to static systems where all required resources must be reserved in advance.
Mass Segregation and the Initial Mass Function of Super Star Cluster M82-F

We investigate the initial mass function and mass segregation in super star cluster M82-F with high-resolution Keck NIRSPEC echelle spectroscopy. Cross-correlation with template supergiant spectra provides the velocity dispersion of the cluster, enabling measurement of the kinematic (virial) mass of the cluster when combined with sizes from NICMOS and Advanced Camera for Surveys (ACS) images. We find a mass of 6.6 ± 0.9 × 105 M☉ based on near-IR light and 7.0 ± 1.2 × 105 M☉ based on optical light. Using PSF-fitting photometry, we derive the cluster's light-to-mass (L/M) ratio in both near-IR and optical light and compare to population-synthesis models. The ratios are inconsistent with a normal stellar initial mass function for the adopted age of 40-60 Myr, suggesting a deficiency of low-mass stars within the volume sampled. King model light profile fits to new Hubble Space Telescope ACS images of M82-F, in combination with fits to archival near-IR images, indicate mass segregation in the cluster. As a result, the virial mass represents a lower limit on the mass of the cluster.
Theory of electronic Raman scattering in nearly antiferromagnetic Fermi liquids

A theory of electronic Raman scattering in nearly antiferromagnetic Fermi liquids is constructed using the phenomenological electron-electron interaction introduced by Millis, Monien, and Pines. The role of ``hot spots'' and their resulting signatures in the channel dependent Raman spectra is highlighted, and different scaling regimes are addressed. The effects of self-consistency and vertex corrections are compared to a perturbative treatment of the interaction. The theory is then compared to Raman spectra taken in the normal state of cuprate superconductors, and it is shown that many features of the symmetry-dependent spectra can be explained by the theory. Remaining questions are addressed.
Structure, spectroscopy and kinetics of the methylene amidogen (H2CN) radical

The physical and chemical properties of methylene amidogen have been reviewed. In general only limited quantatative information is available about the radical and furhher work, both theoretical and experimental, is required. Theoretical studies have met with success but there is much to be done concerning the electron distribution in the ground state of the radical and the structure and energetics of the excited states. While the ground-state geometry seems well defined theoretically, there is still no experimental confirmation of the calculations. A high resolution IR study shoudd provide this confrrmation and may also lead to the development of more sensitive detection techniques such as IR laser absorption spectroscopy and laser magnetic resonance. Should there techniques prove feasible, then coupling of them to the discharge-flow and flash-photolysis methods will allow us to greatly increase our knowledge of the reactivity of H2CN. We have also reviewed several laboratory and atmospheric systems in which H2CN plays a promintnt role. A better understanging of the kinetics of H2CN will lead to improved models of theee complex systems and additional spectroscopic data makes more feasible the in situ detection of thss important chemical intermediate.
Sampling, splines and frames on compact manifolds

Analysis on the unit sphere \(\mathbb {S}^{2}\) found many applications in seismology, weather prediction, astrophysics, signal analysis, crystallography, computer vision, computerized tomography, neuroscience, and statistics. In the last two decades, the importance of these and other applications triggered the development of various tools such as splines and wavelet bases suitable for the unit spheres \(\mathbb {S}^{2}\), \(\>\>\mathbb {S}^{3}\) and the rotation group \(SO(3)\). Present paper is a summary of some of results of the author and his collaborators on the Shannon-type sampling, generalized (average) variational splines and localized frames (wavelets) on compact Riemannian manifolds. The results are illustrated by applications to Radon-type transforms on \(\mathbb {S}^{d}\) and \(SO(3)\).
Group 12 Thiolates: Syntheses, Characterization and Decomposition Pathways

Zinc- and cadmium bis(alkylthiolate) compounds have been prepared and converted into the appropriate binary metal sulfides by thermal treatment. Several mercury chlorothiolates have been synthesized and characterized by single crystal X-ray diffraction. Their decomposition pathways are discussed. The prepared binary metal sulfides have been studied by XRPD and - in selected cases - by particle size determination. The volatile co-products have been isolated and characterized by GC/MS.
Electrostatic potentials for metal-oxide surfaces and interfaces.

As most technologically important metals will form oxides readily, any complete study of adhesion at real metal surfaces must include the metal-oxide interface. The role of this ubiquitous oxide layer cannot be overlooked, as the adhesive properties of the oxide or oxide-metal system can be expected to differ profoundly from the adhesive properties of a bare metal surface. We report on the development of a computational method for molecular-dynamics simulations, which explicitly includes variable charge transfer between anions and cations. This method is found to be capable of describing the elastic properties, surface energies, and surface relaxation of crystalline metal oxides accurately. We discuss in detail results using this method for \ensuremath{\alpha}-alumina and several of its low-index faces.
Multistability and perceptual inference

Ambiguous images present a challenge to the visual system: How can uncertainty about the causes of visual inputs be represented when there are multiple equally plausible causes? A Bayesian ideal observer should represent uncertainty in the form of a posterior probability distribution over causes. However, in many real-world situations, computing this distribution is intractable and requires some form of approximation. We argue that the visual system approximates the posterior over underlying causes with a set of samples and that this approximation strategy produces perceptual multistability-stochastic alternation between percepts in consciousness. Under our analysis, multistability arises from a dynamic sample-generating process that explores the posterior through stochastic diffusion, implementing a rational form of approximate Bayesian inference known as Markov chain Monte Carlo (MCMC). We examine in detail the most extensively studied form of multistability, binocular rivalry, showing how a variety of experimental phenomena-gamma-like stochastic switching, patchy percepts, fusion, and traveling waves-can be understood in terms of MCMC sampling over simple graphical models of the underlying perceptual tasks. We conjecture that the stochastic nature of spiking neurons may lend itself to implementing sample-based posterior approximations in the brain.
Platinum(II)-catalyzed intermolecular hydroamination of monosubstituted allenes with secondary alkylamines.

A 1 ∶ 1 mixture of (dppf)PtCl2 and AgOTf (5 mol%) catalyzed the intermolecular hydroamination of monosubstituted allenes with secondary alkylamines at 80 °C to form allylic amines in good yield with selective formation of the E-diastereomer.
The Politics of Liberalizing Zambia's Maize Markets

Abstract This paper discusses the process of agricultural liberalization in Zambia. The central argument is that maize markets have been more quickly and fully liberalized than maize input markets because the perceived political risks of liberalizing input markets are greater than those of liberalizing maize markets, and because economic interest groups benefited from maize liberalization while similar interests benefited from continued government interventions in input markets. These finding imply that in order to understand the prospects for economic liberalization in new democracies we must disaggregate both civil society and markets.
Suzuki–Miyaura Cross-Coupling Reactions of Potassium Boc-Protected Aminomethyltrifluoroborate with Aryl- and Hetaryl Mesylates

Palladium-catalyzed Suzuki–Miyaura cross-coupling reactions were studied with potassium Boc-protected aminomethyltrifluoroborate through C–O activation of various mesylate derivatives to afford the corresponding products in moderate to good yields.
Electrophilic and nucleophilic reactions of complexes formed from 2,5-dithiahex-3-yne (MeSCCSMe) and tungsten carbonyls

Abstract The alkyne, MeSCCSMe, reacts with tungsten(II) carbonyl complexes to yield π-alkyne products, CpW(η2-MeSCCSMe)2Cl (1), W(CO)(η2-MeSCCSMe)(S2CNR2)2 (R = Me (2a) and Et (2b)), and W(η2-MeSCCSMe)2(S2CNR2)2 (R = Me (3a) and Et (3b)). The sulfonium complex [CpClW(η2-MeSCCSMe)(η2-MeSCCSMe2)]BF4 (4), whose structure was established by an X-ray diffraction study, was prepared by the reaction of 1 with Me3O+. The Cp(PMe3)2Ru+ group also adds to a sulfur in 1 to give {CpClW(η2-MeSCCSMe)[η2-MeSCCS(Me)Ru(PMe3)2Cp]}BF4 (5). Nucleophilic attack by H− donors and RS− on 4 displaces Me2S to yield CpW(η2-MeSCCSMe)(η2-MeSCCX)Cl (X = H (6), SC6H5 (7a), and 4-SC6H4Me (7b)) and Me2S.
New similarity solutions for hypersonic boundary layers with applications to inlet flows

A re-examination of self-similar solution possibilities for steady laminar boundary layers is given for nonadiabatic strongly hypersonic flows of an ideal gas. Two apparently new solutions are found, pertaining to adverse pressure gradients, both of which involve no separation with distance into the pressure rise. The first involves an exponential pressure rise on a cooled similarly shaped body, whereas the second involves a modified ramp type pressure rise. The skin friction, heat transfer, displacement thickness, and weak viscous interaction-induced pressure change properties of these two solution families are analyzed in detail, including their application to high-speed inlet type of flows.
Biomimetic Synthesis and Structure Elucidation of Rubicordifolin, a Cytotoxic Natural Product from Rubia cordifolia

The biomimetic synthesis and full structural elucidation of rubicordifolin, a cytotoxic natural product isolated from Rubia cordifolia, is described.
ALKYLTHIOETHER SYNTHESIS VIA IMIDAZOLE MEDIATED MITSUNOBU CONDENSATION

Abstract Unsymmetric alkylthioethers can be prepared from aliphatic thiols and unhindered alcohols under modified Mitsunobu conditions using trimethylphosphine/1,1′-(azodicarbonyl)dipiperdine (ADDP) in the presence of imidazole (2 equivalents).
DC electrification supply system design

Railway electrification has in the past been dominated by overhead contact wire and DC third/ fourth conductor rail electrification systems. The historical reasons for this have been the success of the DC traction motor and the necessity of a DC supply. Mercury arc rectifiers were originally used to provide rectification at substations with the DC power being transmitted to the traction equipment by the conductor rail or overhead wire. Success in producing mercury arc rectifiers capable of being operated on board the railway vehicle, enabled railway AC electrification systems to become a reality in the 1950/60's. It should be noted that DC is still the most common form of railway electrification system in the world.
The Long‐run Performance Following Dividend Initiations and Resumptions: Underreaction or Product of Chance?

We examine the long-term stock performance following dividend initiations and resumptions from 1927 to 1998. We show that postannouncement abnormal returns are significantly positive for equally weighted calendar time portfolios, but become insignificant when the portfolios are value weighted. Moreover, the equally weighted results are not robust across subsamples. We also document postannouncement reductions in the risk factor loadings of underlying stocks. Crosssectionally, these reductions are negatively related to the contemporaneous price drifts, suggesting the price drifts may be a sample-specific result of chance. Our results underscore the importance of testing for changes in risk loadings in future long-term event studies. AN INCREASINGLY IMPORTANT ISSUE in the study of financial markets is to understand the causes of the apparent abnormal equity price drifts or anomalies that are shown to follow various types of corporate events. In this paper, we address this issue within the context of dividend policy. We examine the longterm stock performance following the initiation and resumption of cash dividends during the period from 1927 to 1998. Although Michaely, Thaler, and Womack ~1995! document a positive price drift for firms that initiate dividends during the 1964 to 1988 period, we can replicate their findings only for equally weighted portfolios and only for dividend events that occurred during the post-1964 period. This lack of intertemporal and methodological robustness suggests that the results of Michaely et al. may simply be due to chance. We find no evidence of any abnormal price drift for the period prior to 1964. In addition, when portfolios are value weighted by market capitalization, the price drift of the post-1964 period disappears. The discrepancy between equal and value weighting is due to the absence of any long-term abnormal returns for the largest size decile. When this decile is excluded from the value-weighted analysis, the abnormal returns are again signifi* Boehme and Sorescu are from the C.T. Bauer College of Business, University of Houston. This paper has benefited from the comments of Richard Green, an anonymous referee, Tom Berglund, Bartley Danielsen, Mark Flannery, Peter Hogfeldt, Jan Jindra, and Praveen Kumar. We thank Wanhai Liu for excellent research assistance. We also thank program participants at the 2000 meetings of the European Finance Association and the Financial Management Association, and seminar participants at the Stockholm School of Economics and the Swedish School of Economics and Business Administration.
Structural Issues in Conjugated Hydrocarbons: High-Resolution Infrared Slit-Jet Spectroscopy of trans -1,3-Butadiene

First high-resolution spectroscopic and structural data for jet-cooled trans-1,3-butadiene have been obtained using sub-Doppler, direct absorption tunable difference frequency infrared laser methods in a pulsed slit supersonic expansion. With reduced spectral congestion at T r o v i b = 15 K, high-resolution vibration-rotation spectra around 3100 cm - 1 reveal two hybrid a/b type bands, both of which have been successfully rotationally analyzed and yield first experimental structural information on the ground state of trans-1,3-butadiene. The strong band v 1 7 (b u ) at 3100.63 cm - 1 is predominantly due to "bright" state excitation of the in-phase asymmetric CH 2 stretch, with the weaker band at 3096.14 cm - 1 probably arising from a "dark" state anharmonic mixing with v 1 7 . Furthermore, there are many local perturbations in the spectrum that can be successfully explained via anharmonic and Coriolis type coupling between v 1 7 and an additional dark state centered at 3100.65 cm - 1 . Intensity analysis for the strong and weak bands permits a- and b-type transition moment ratios to be extracted and compared with results from electronic structure calculations.
Note on a problem with Reed and Long's FBR results

This short note discusses a problem we found in a recent article in Operating Systems Review [1]. The problem is related to apparent inconsistencies in results presented for a data cache algorithm, known as FBR (frequency based replacement), which we first described in [2]. A property of this algorithm is that cache miss ratios obtained using FBR can be related to LRU cache miss ratios for any given trace. Application of this property to the results in [1] reveals apparent inconsistencies. These inconsistencies could be the result of errors either in implementing the algorithm or in recording the results. This note also highlights this property of FBR, which should help contribute to its understanding.
Epidemiology of Osteoarthritis

Osteoarthritis (OA) is the most common joint disorder in the United States. Symptomatic knee OA occurs in 10% men and 13% in women aged 60 years or older. The number of people affected with symptomatic OA is likely to increase due to the aging of the population and the obesity epidemic. OA has a multifactorial etiology, and can be considered the product of an interplay between systemic and local factors. Old age, female gender, overweight and obesity, knee injury, repetitive use of joints, bone density, muscle weakness, and joint laxity all play roles in the development of joint OA, particularly in the weight-bearing joints. Modifying these factors may reduce the risk of OA and prevent subsequent pain and disability.
Estimation of AR(1) models with unequally spaced pseudo-panels

This paper provides for the estimation of dynamic pseudo-panel models with such data. Non linear least squares, minimum distance, and one-step estimators are used to impose the non linear parameter restrictions which occur in dynamic models over unequally spaced periods. Consistency and asymptotic normality of the estimators is established. A small-scale Monte Carlo simulation study corroborates the results. The paper also shows how these methods can be applied to allow estimation of dynamic models with irregularly spaced genuine panel data.
Prosocial lies: When deception breeds trust

Philosophers, psychologists, and economists have long asserted that deception harms trust. We challenge this claim. Across four studies, we demonstrate that deception can increase trust. Specifically, prosocial lies increase the willingness to pass money in the trust game, a behavioral measure of benevolence-based trust. In Studies 1a and 1b, we find that altruistic lies increase trust when deception is directly experienced and when it is merely observed. In Study 2, we demonstrate that mutually beneficial lies also increase trust. In Study 3, we disentangle the effects of intentions and deception; intentions are far more important than deception for building benevolence-based trust. In Study 4, we examine how prosocial lies influence integrity-based trust. We introduce a new economic game, the Rely-or-Verify game, to measure integrity-based trust. Prosocial lies increase benevolence-based trust, but harm integrity-based trust. Our findings expand our understanding of deception and deepen our insight into the mechanics of trust.
The Altered Mononuclear Cell-Derived Cytokine Response to Glucose Ingestion Is Not Regulated by Excess Adiposity in Polycystic Ovary Syndrome

Context: Excess adipose tissue is a source of inflammation. Polycystic ovary syndrome (PCOS) is a proinflammatory state and is often associated with excess abdominal adiposity (AA) alone and/or frank obesity. Objective: To determine the effect of glucose ingestion on cytokine release from mononuclear cells (MNC) in women with PCOS with and without excess AA and/or obesity. Design: A cross-sectional study. Setting: Academic medical center. Patients: Twenty-three women with PCOS (seven normal weight with normal AA, eight normal weight with excess AA, eight obese) and 24 ovulatory controls (eight normal weight with normal AA, eight normal weight with excess AA, eight obese). Intervention: Three-hour 75-g oral glucose tolerance test (OGTT). Main Outcome Measures: Body composition was measured by dual energy x-ray absorptiometry. Insulin sensitivity was derived from the OGTT (ISOGTT). TNFα, IL-6, and IL-1β release was measured in supernatants of cultured MNC isolated from blood samples drawn while fasting and ...
Models of Chemistry, Thermal Balance, and Infrared Spectra from Intermediate-Aged Disks around G and K Stars

We model gas and dust emission from regions 0.3-20 AU from a central low-mass star in intermediate-aged (~107 yr) disks whose dust is fairly optically thin to stellar radiation. The models treat thermal balance and chemistry self-consistently and calculate the vertical density and temperature structure of the gas in a disk. The gas and dust temperatures are calculated separately. The models cover gas masses 10-3 to 1 MJ and dust masses 10-7 to 10-4 MJ and treat solar-type (G and K) stars. We focus on mid-infrared and far-infrared emission lines from various gas species such as the rotational lines of H2, OH, H2O, and CO molecules and the fine-structure lines of carbon, oxygen, sulfur, iron, and silicon atoms and ions. These lines and the dust continuum are observable by the Spitzer Space Telescope and future missions including SOFIA and the Herschel Space Observatory. We find that the [S I] 25.23 μm line is the strongest emission line for a wide range of disk and stellar parameters, followed by emission from [Si II] 34.8 μm, [Fe II] 26 μm, and [O I] 63 μm. [Fe I] 24 μm and rotational lines of OH and H2O are strong when gas masses are high (0.1 MJ). Emission from the rotational lines of H2 is more difficult to detect unless disk gas masses are substantial (0.1 MJ). For emission from H2 lines to be observable and yet for the dust to be optically thin in stellar light, the ratio of gas to small submillimeter-sized dust particle mass in the disk needs to be 1000, or at least an order of magnitude higher than that in the interstellar medium. This may be possible at intermediate stages in disk evolution, such as in the gas-gathering stage of the core accretion scenario for giant planet formation, in which most of the dust has coagulated into larger objects (1 mm) but the gas has not yet fully dispersed. Whereas the absolute fluxes observed in some lines such as [Fe I] 24 μm and H2 S(0) 28 μm primarily measure the gas mass in the disks, various line ratios diagnose the inner radius of the gas and the radial temperature and surface density distribution of the gas. Many lines become optically thick and/or suffer chemical or thermal effects such that the line luminosities do not increase appreciably with increasing gas mass. We predict that it may be difficult for the Spitzer Space Telescope to detect 1 MJ of gas in optically thin (in dust) disks at distances 150 pc. The models presented here will be useful in future infrared studies of the timescale for the dispersion of gas in a planet-forming disk and tests of core accretion models of giant planet formation.
From International Relations to Global Governance Theory: Conceptualizing NGOs after the Rio Breakthrough of 1992

Abstract This essay systematizes the ontology of non-governmental organizations (NGOs) and the processes of their inclusion in world politics. It tracks conceptualizations of NGOs, their integration into IR theory, and the resultant move toward global governance (GG) theory. First, I provide an interdisciplinary ontological evolution of NGOs in international relations (IR): as international interest groups, then transnational social movement organizations, then transnational advocacy networks, and most recently as global civil society. All stress different features of NGO activism, but none have successfully replaced the term ‘NGO.’ Second, this new ontology requires a new process for participation in world politics—GG. GG theory expands on IR theory to include NGOs in multi-actor, issue-driven relationships.
Offshore Ekman transport and Ekman pumping off Peru during the 1997–1998 El Niño

[1] Satellite ocean vector wind measurements are used to describe onshore-offshore Ekman transport and Ekman pumping/suction (i.e., downward/upward velocity) in the coastal ocean at 15°S off Peru, where upwelling is the dominant physical process. Normal and El Nino conditions are defined for May 1992 – April 1997 and May 1997 – May 1998, respectively. During normal conditions, both Ekman suction and offshore Ekman transport produced upwelling. During the El Nino, the May–August speed of Ekman pumping (−9 × 10−6 m s−1) was nearly 4 times larger than the normal speed of Ekman suction and offshore Ekman transport nearly doubled. The strong Ekman pumping may be the source for the deepened coastal thermocline during El Nino, although the evidence is not conclusive because of the absence of in situ observations.
Synthesis of Seven-Membered Carbocyclic Rings via a Microwave-Assisted Tandem Oxyanionic 5-Exo Dig Cyclization-Claisen Rearrangement Process

Appropriately substituted 1-alkenyl-4-pentyn-1-ol systems, readily prepared from simple starting materials, serve as useful precursors to a number of substituted cyclohept-4-enone derivatives via a microwave-assisted tandem oxyanionic 5-exo cyclization/Claisen rearrangement sequence. The reactions involving terminally substituted 4-pentyn-1-ols were found to be highly stereoselective, with the α and β groups in the final product showing a strong preference for the trans orientation.