cssi/SciSciGPT-SciSciNet huggingface dataset:
Low-Luminosity Companions to White Dwarfs

This paper presents results of a near-infrared imaging survey for low-mass stellar and substellar companions to white dwarfs. A wide-field proper-motion survey of 261 white dwarfs was capable of directly detecting companions at orbital separations between ~100 and 5000 AU with masses as low as 0.05 M?, while a deep near-field search of 86 white dwarfs was capable of directly detecting companions at separations between ~50 and 1100 AU with masses as low as 0.02 M?. Additionally, all white dwarf targets were examined for near-infrared excess emission, a technique capable of detecting companions at arbitrarily close separations down to masses of 0.05 M?. No brown dwarf candidates were detected, which implies a brown dwarf companion fraction of <0.5% for white dwarfs. In contrast, the stellar companion fraction of white dwarfs as measured by this survey is 22%, uncorrected for bias. Moreover, most of the known and suspected stellar companions to white dwarfs are low-mass stars whose masses are only slightly greater than the masses of brown dwarfs. Twenty previously unknown stellar companions were detected, five of which are confirmed or likely white dwarfs themselves, while 15 are confirmed or likely low-mass stars. Similar to the distribution of cool field dwarfs as a function of spectral type, the number of cool unevolved dwarf companions peaks at mid-M type. Based on the present work, relative to this peak, field L dwarfs appear to be roughly 2-3 times more abundant than companion L dwarfs. Additionally, there is no evidence that the initial companion masses have been altered by post-main-sequence binary interactions.
Intertwining operators of double affine Hecke algebras

A systematic study of the representation theory of double affine Hecke algebras and related harmonic analysis is started in this paper. Continuing the previous papers we use the technique of intertwining operators to create Macdonald polynomials, estimate their denominators, generalize the classical representations of p-adic affine Hecke algebras in the spaces of functions on affine Weyl groups, and to find out when induced representations are irreducible and co-spherical. The connection with recent results by Sahi and Knop on the integrality of the Macdonald polynomials is established.
Transient engine performance with water ingestion

The immediate effects on the transient performance of a generic, high bypass ratio jet engine on account of water ingestion are discussed. The air compression subsystem has been analyzed with respect to four aerothermodynamic and mechanical processes associated with two-phase fluid flow and the engine simulation has been carried out under three limiting cases of interest in practice, one pertaining to draining of water at the end of compression and the other two, to partial evaporation at two different locations in the burner. General observations are made on engine operability as a function of engine and control design under various engine and (control input) sensor operating conditions, with various mass fractions of water in the air-water mixture entering the engine, during various pilot-initiated power demand changes.
Entanglement measures as physical observables

We discuss why regular observables cannot be proper entanglement measures, and how observables in a generalized setting can be used to make an entanglement monotone a directly observable quantity for the case of pure states. For the case of mixed states, these generalized observables can be used to find valid lower bounds on entanglement monotones that can be measured in laboratory experiments in the same fashion as it can also be done for pure states.
Hierarchical Representation of Chain-Encoded Binary Image Contours

A hierarchical scheme for chain-encoded digital contours is introduced. If the contour represents the boundary of a binary image, a true digitization of the image is realized as the pyramid structure goes from the fine to coarser resolution levels. A progressive transmission system is designed to go from a coarse resolution level to finer levels which uses essentially the same number of bits as transmission of the contour at the finest resolution.
How to build programmable multi-core chips

The arrival of multi-core chips has heightened interest in the discipline of parallel programming, a topic that has received much attention for many years. Computer architects have much to learn from sound principles for structuring software and expressing parallel computation. This talk will cover principles for the design of computer systems to support composable parallel software - the idea that any parallel program is usable, without change, as a component of larger parallel programs. By following these principles, a revolution in the ease of building robust and high-performance parallel software can be achieved. The principles suggest interesting directions for computer architecture; the tools to experiment with new architecture concepts are ready and waiting for the savvy and ambitious researcher.
Decentralized computation procurement and computational robustness in a smart market

Several `smart market' mechanisms have recently appeared in the literature. These mechanisms combine a computer network that collects bids from agents with a central computer that selects a schedule of bids to fill based upon maximization of revenue or trading surplus. Potential problems exist when this optimization involves combinatorial difficulty sufficient to overwhelm the central computer. This paper explores the use of a computation procuring clock auction to induce human agents to approximate the solutions to discrete constrained optimization problems. Economic and computational properties of the auction are studied through a series of laboratory experiments. The experiments are designed around a potential application of the auction as a secondary institution that approximates the solution to difficult computational problems that occur within the primary `smart market', and show that the auction is effective and robust in eliciting and processing suggestions for improved schedules.
Selected design issues of some high-speed rotorcraft concepts

A study of vehicle concepts for High Speed Rotorcraft applications has been undertaken at Ames Research Center in cooperation with NASA Lewis and Langley Centers, with the objective of defining their technology needs. The design guidelines include a low downwash velocity in hover, good low speed maneuver capabilities and cruise speeds up to 450 knots. Four contractors and a systems analysis effort within NASA have defined promising configurations which may be capable of meeting these goals. This paper addresses challenging problems associated with some of the configurations in the areas of aerodynamics, propulsion, weights and aeroelastic stability.
On testing the adequacy of stable processes under conditional heteroscedasticity

Abstract We consider a recently proposed method of estimating the tail index and testing the goodness-of-fit of dependent stable processes. Through Monte Carlo simulations, we evaluate the ability of the procedure to distinguish between stable and non-stable processes in the presence of non-linear dependence and to estimate the tail index of the distribution. We then apply the test to black market East European exchange rates, whose distributional and tail behaviour has been analysed previously in the literature. After adjusting for seasonality, we conclude, unlike the earlier analysis, that a stable process cannot be rejected as a model for some of the currencies. Estimates of the tail index for these currencies are also obtained.
Centrally Condensed Collapse of Starless Cores

Models of self-gravitating gas in the early stages of pressure-free collapse are compared for initial states that are equilibrium layers, cylinders, and "Bonnor-Ebert" spheres. For each geometrical case the density profile has an inner region of shallow slope surrounded by an outer region of steep slope, and the profile shape during early collapse remains similar to the profile shape of the initial equilibrium. The two-slope density structure divides the spherical collapse history into a starless infall phase and a protostellar accretion phase. The similarity of density profiles implies that Bonnor-Ebert fits to observed column density maps may not distinguish spherical cores from oblate or prolate cores and may not distinguish static cores from collapsing cores. The velocity profiles discriminate better than the density profiles between initial geometries and between collapse ages. The infall velocity generally has a subsonic maximum value, which is approximately equal to the initial velocity dispersion times the ratio of collapse age to central free-fall time. Observations of starless-core line profiles constrain collapse models. Collapse from initial states that are strongly condensed and slightly prolate is consistent with "infall asymmetry" observed around starless cores and is more consistent than collapse from initial states that are weakly condensed and/or oblate. Spherical models match observed inward speeds of 0.05-0.09 km s-1 over 0.1-0.2 pc if the collapse has a typical age of 0.3-0.5 free-fall times and if it began from a centrally condensed state that was not in stable equilibrium. In a collapsing core, optically thin line profiles should broaden and develop a two-peak structure, as seen in L1544, once the typical infall velocity approaches the molecular velocity dispersion or when the collapse age exceeds ~0.4 free-fall times, for typical parameters, independent of depletion.
Haloes of k-essence

We study gravitationally bound static and spherically symmetric configurations of k-essence fields. In particular, we investigate whether these configurations can reproduce the properties of dark matter haloes. The classes of Lagrangians we consider lead to non-isotropic fluids with barotropic and polytropic equations of state. The latter include microscopic realizations of the often-considered Chaplygin gases, which we find can cluster into dark matter halo-like objects with flat rotation curves, while exhibiting a dark energy-like negative pressure on cosmological scales. We complement our studies with a series of formal general results about the stability and initial value formulation of non-canonical scalar field theories, and we also discuss a new class of de Sitter solutions with spacelike field gradients.
Resolution of Proliferation Issues for a Sodium Fast Reactor Blanket

Breeding blankets are of interest for a sodium fast reactor (SFR) as they allow for small cores to have positive breeding gains. However, because they breed very high-quality plutonium, core design...
Measurement of rocking curve wings at high x-ray energies

Abstract Measurements done recently at the NSLS have indicated that the level of intensity found in the wings of diffraction peaks from silicon at higher X-ray energies (> 20 keV) far exceeds the value which would be predicted based on the dynamical theory. We have measured Si(220) double crystal rocking curves at the 40 keV fundamental and harmonics with various crystal scattering geometries: Bragg-Bragg, Laue-Bragg, Laue-Laue. The comparison of the Bragg and Laue case diffraction geometries was done to determine scattering volume effects. Comparisons with dynamical theory calculations will be discussed. These measurements have been carried out in order to assess the level of harmonic contamination which will be present from a double crystal monochromator being designed for the X17 superconducting wiggler beamline.
Flexible Ag electrode for use in organic photovoltaics

High efficiency organic photovoltaic cells discussed in literature are normally restricted to devices fabricated on glass substrates. This is a consequence of the extreme brittleness and inflexibility of the commonly used transparent conductive oxide electrode, indium tin oxide (ITO). This shortcoming of ITO along with other concerns such as increasing scarcity of indium, migration of indium to organic layer, etc. makes it imperative to move away from ITO. Here we demonstrate a highly flexible Ag electrode that possesses low sheet resistances even in ultra-thin layers. It retains its conductivity under severe bending stresses where ITO fails completely. A P3HT:PCBM blend organic solar cell fabricated on this highly flexible electrode gives an efficiency of 2.3%.
Ethnic Diversity and Organizational Performance: Assessing Diversity Effects at the Managerial and Street Levels

ABSTRACT As the public sector workforce becomes more ethnically diverse and as government agencies make attempts to manage that diversity, the importance of understanding how diversity affects workplace interactions and work-related outcomes increases. Little public-sector research has examined the impact of diversity on performance outcomes. This article seeks to fill this gap by studying the effects of the ethnic diversity of managers and street level public officials on work-related outcomes. We use basic in-group/out-group theories from psychology to formulate research questions relating diversity and performance, along with empirical research on the effects of diversity on work-related outcomes. We then use data from schools to test the relationship between ethnic diversity and organizational performance, identifying different impacts for managerial diversity and diversity among teachers. Results are consistent across three different models: manager diversity is routinely non-significant in predictin...
Cardiovascular effects of topical 50% trichloroacetic acid and Baker's phenol solution.

. Phenol and trichloroacetic acid (TCA) are used for cosmetic face peeling. Deaths associated with phenol have been ascribed to the cardiotoxicity. Our purpose has been to study and compare the cardiovascular responses to these two agents in a rat model. Fifteen rats underwent abdominal epilation. Two to six days later a surface area comparable to the human face (16 cm2) was delineated on the abdomen. Baker's phenol or 50% TCA was applied to this area. Cardiac rate and rhythm and arterial pressure were monitored. Once stable, the same agent was applied to the entire abdomen for further study. TCA has been shown to be a safer agent than phenol in this rat model. Assuming that this model simulates the human response, monitoring would appear to be indicated during full-face Baker's phenol peeling.
An Indicator of Future Inflation Extracted from the Steepness of the Interest Rate Yield Curve Along Its Entire Length

The term-structure slope contains information about expected future inflation. Mishkin shows that the spread between the twelve-month and three-month interest rates helps predict the difference between twelve-month and three-month inflation. We apply a simple existing framework, which lets the real interest rate vary in the short run but converge to a constant in the long run, to this problem. The appropriate indicator of expected inflation uses the entire length of the yield curve, estimating the steepness of a specific nonlinear transformation, rather than being restricted to a spread between two points. The resulting indicator better predicts inflation, over 1960–1991.
An empirical evaluation of four variants of a universal species-area relationship.

The Maximum Entropy Theory of Ecology (METE) predicts a universal species–area relationship (SAR) that can be fully characterized using only the total abundance (N) and species richness (S) at a single spatial scale. This theory has shown promise for characterizing scale dependence in the SAR. However, there are currently four different approaches to applying METE to predict the SAR and it is unclear which approach should be used due to a lack of empirical comparison. Specifically, METE can be applied recursively or non-recursively and can use either a theoretical or observed species-abundance distribution (SAD). We compared the four different combinations of approaches using empirical data from 16 datasets containing over 1000 species and 300,000 individual trees and herbs. In general, METE accurately downscaled the SAR (R2 > 0.94), but the recursive approach consistently under-predicted richness. METE’s accuracy did not depend strongly on using the observed or predicted SAD. This suggests that the best approach to scaling diversity using METE is to use a combination of non-recursive scaling and the theoretical abundance distribution, which allows predictions to be made across a broad range of spatial scales with only knowledge of the species richness and total abundance at a single scale.
Durables, nondurables, down payments and consumption excesses ☆

Abstract We examine a model that generalizes the standard buffer-stock model of saving to accommodate durables, nondurables, down payment requirements, and adjustment costs in the durables market. We find that nondurable consumption becomes more volatile relative to income as down payments decrease at the individual and at the aggregate level. Moreover, for plausible parameter values, the model can explain the excess smoothness and excess sensitivity observed in U.S. aggregate data. The result follows from a gradual adjustment of consumption to permanent income shocks when agents attempt to spread out the burden of down payments over time, compounded by slow adjustment due to transaction costs.
On a Parametrization of Positive Semidefinite Matrices with Zeros

We study a class of parametrizations of convex cones of positive semidefinite matrices with prescribed zeros. Each such cone corresponds to a graph whose nonedges determine the prescribed zeros. Each parametrization in this class is a polynomial map associated with a simplicial complex supported on cliques of the graph. The images of the maps are convex cones, and the maps can only be surjective onto the cone of zero-constrained positive semidefinite matrices when the associated graph is chordal and the simplicial complex is the clique complex of the graph. Our main result gives a semialgebraic description of the images of the parametrizations for chordless cycles. The work is motivated by the fact that the considered maps correspond to Gaussian statistical models with hidden variables.
Gravity dual of dynamically broken supersymmetry

We study a renormalization group flow of ABJM theory embedded into the warped A 8 geometry and explore the dependence of the vacuum structure on the parameters of the theory. This model has a product group gauge structure U(N) k × U(N + l)−k and comes equipped with discrete parameters N, l, and k, a continuous parameter b ∞ related to the ratio of the Yang-Mills coupling for the two gauge groups, and one dimensionful parameter $ g_{YM}^2 $ setting the overall scale. A supersymmetric supergravity solution exists when Q = N − l(l − k)/2k − k/24 is positive and is interpretable as a RG flow from a Yang-Mills like UV fixed point to a superconformal IR fixed point with free energy of order Q 3/2. The fate of the theory when Q is taken to be negative is less clear. We explore the structure of the possible gravity solution for small negative Q by considering the linearized gravitational back reaction from adding a small number of anti-branes on the Q = 0 background. Following the work of Bena, Grana, and Halmagyi, we find that a sensible solution satisfying appropriate boundary conditions does not appear to exist. This leaves the status of the RG flow for the Q < 0 theories a mystery. We offer the following speculative resolution to the puzzle: the −k/24 unit of charge induced by the curvature correction to supergravity should be considered an allowed physical object, and one should be adding an anti brane not to the Q = 0 background but rather the Q = −k/24 background. Such a solution has a repulson singularity, and gives rise to a picture of the vacuum configuration where a cluster of anti-branes are floating around the repulson singularity, but are stabilized from being pushed off to infinity by other fluxes. Such a state is non-supersymmetric and appears to describe a vacuum with dynamical breaking of supersymmetry. Based on these considerations, we construct a phase diagram for this theory exhibiting various interesting regions.
Turbulent static pressure fluctuations away from flow boundaries

A technique for measuring static pressure fluctuations and the pressure-velocity correlation away from walls in interior and exterior turbulent flows is described. Direct response calibration using Fourier transform techniques enables the use of a microphone pitot probe and a hot-film sensor to derive the static pressure spectrum. Experiments verifying the assumptions made in using this technique are described. Theoretical computations are made that show excellent agreement with the measured values. The pressure fluctuations away from walls are seen to be much larger than those sensed by wall-mounted transducers.
Discriminative stimulus effects of nalbuphine in nontreated and morphine-treated pigeons.

In the present study, the stimulus effects of the low efficacy agonist nalbuphine were examined under two conditions: nontreated and morphine treated. In the first experiment, five pigeons were trained to discriminate among 3.2 mg/kg morphine, 5.6 mg/kg nalbuphine, and saline. Nalbuphine produced nalbuphine-like responding. Low doses of morphine produced nalbuphine-like responding, whereas high doses produced morphine-like responding. Naltrexone produced saline-like responding and reversed the stimulus effects produced by the training doses of morphine and nalbuphine. Five different pigeons were treated daily with 10 mg/kg morphine (IM) and trained 6 h later to discriminate among 10 mg/kg morphine, 1.0 mg/kg nalbuphine and saline. In these pigeons, morphine produced morphine-like responding and nalbuphine produced nalbuphine-like responding. Morphine abstinence produced nalbuphine-like responding that was reversed by morphine. Additionally, naltrexone produced nalbuphine-like responding. These data suggest that the discrimination between morphine and nalbuphine in the nontreated and morphine-treated pigeons may be based on the relative efficacy differences between morphine, a higher efficacy μ-agonist, and nalbuphine a lower efficacy μ-agonist.
BULK COMPTONIZATION OF THE COSMIC MICROWAVE BACKGROUND BY EXTRAGALACTIC JETS AS A PROBE OF THEIR MATTER CONTENT

We propose a method for estimating the composition, i.e. the relative amounts of leptons and protons, of extragalactic jets which exhibit Chandra - detected knots in their kpc scale jets. The method relies on measuring, or setting upper limits on, the component of the Cosmic Microwave Background (CMB) radiation that is bulk-Comptonized by the cold electrons in the relativistically flowing jet. These measurements, along with modeling of the broadband knot emission that constrain the bulk Lorentz factor GAMMA of the jets, can yield estimates of the jet power carried by protons and leptons. We provide an explicit calculation of the spectrum of the bulk-Comptonized (BC) CMB component and apply these results to PKS 0637 - 752 and 3C 273, two superluminal quasars with Chandra - detected large scale jets. What makes these sources particularly suited for such a procedure is the absence of significant non-thermal jet emission in the 'bridge', the region between the core and the first bright jet knot, which guarantees that most of the electrons are cold there, leaving the BC scattered CMB radiation as the only significant source of photons in this region. At lambda = 3.6 - 8.0 microns, the most likely band to observe the BC scattered CMB emission, the Spitzer angular resolution (approximately 1" - 3") is considerably smaller than the the 'bridges' of these jets (approximately 10"), making it possible to both measure and resolve this emission.
The Policy Function of a Discrete‐Choice Problem is a Random Number Generator

This paper studies a life-cycle model in which the consumption good is assumed to be indivisible. This assumption requires the number of units of the good purchased in each period to be an integer. It is shown that, if the discount factor (β) is sufficiently small, the policy function takes the form of a pseudo-random number generator or, more precisely, a linear congruential generator. It is also shown that optimal plans are almost always asymptotically non-periodic regardless of the discount factor. Various numerical examples of the value function and the policy function are provided. JEL Classification Numbers: C61, D91, E32.
Models and experiments on degradation of oxidized silicon

Abstract The concepts of electronic and protonic traps are introduced to delineate and classify the fundamental mechanisms of charging, generation, annealing and hydrogenation of electronic or electron and hole traps located in the interfacial (gate-conductor/oxide, oxide/nitride and oxide/silicon), insulator (oxide, nitride and oxynitride) and semiconductor surface layers of silicon MOS transistors and integrated circuits. Two matrix tables, one without tunneling (3 × 3) and one with tunneling (3 × 4) are used to classify the trap charging and electronic injection mechanisms according to the initial and final (band or bound) states of the electronic transition and the energy exchange mechanisms (thermal, optical and Auger-impact). The importance of tunneling to and from traps (TTT) as an oxide charge build-up mechanism is discussed. A theoretical tunneling rate to traps is given showing that traps shallower than about 2 eV from the oxide conduction band edge or 3 eV from the oxide valence band edge cannot be charged by the TTT transitions alone. Experimental examples illustrating the use of these mechanism tables as well as the importance of breaking hydrogen and strained intrinsic bonds by hot electron impact and by thermal hole capture are discussed, including: (i) annealing of the oxide/Si interface traps via hydrogenation during 380C chip bonding and during Fowler-Nordheim tunneling electron injection (FN-TEI) and avalanche electron injection (AEI) stresses, (ii) interface trap generation and positive oxide charge build-up during electron injection via FN-TEI or AEI, and (iii) electrical deactivation of boron and other group-III acceptors (Al, Ga, In) in the silicon surface layer during FNTEI or AEI stresses. Examples at three d.c. bias conditions to delineate the dominant degradation mechanisms in silicon MOS transistors are given showing that trap charging via tunneling (FNTEI, FNTHI and TTT) dominates below about 3.3 V in both n -MOS and p -MOS but trap generation via bond breaking by thermal hole capture may also occur in low voltage p -MOS. Higher than about 10 V, tunneling (FNTEI, FNTHI and TTT) and avalanche injection (AEI and AHI) as well as hydrogen and intrinsic bond-breaking may all be important degradation mechanisms.
Hex-dominant mesh generation using 3D constrained triangulation

A method for decomposing a volume with a prescribed quadrilateral surface mesh, into a hexahedral-dominated mesh is proposed. With this method, known as Hex-Morphing (H-Morph), an initial tetrahedral mesh is provided. Tetrahedral are transformed and combined starting from the boundary and working towards the interior of the volume. The quadrilateral faces of the hexahedra are treated as internal surfaces, which can be recovered using constrained triangulation techniques. Implementation details of the edge and face recovery process are included. Examples and performance of the H-Morph algorithm are also presented.
Coca and cocaine as medicines: An historical review

Coca has been used in folk medicine in South America for thousands of years both as a general stimulant and for more specific medical purposes. It remains one of the most commonly used medicines in some areas of Bolivia and Peru. The medical use of coca and cocaine in the industrial world has a more dramatic and varied history. Coca extract and cocaine were introduced as pancreas for a wide variety of complaints in the late 19th century. Cocaine was the first effective local anesthetic; prescription drugs, patent medicine, and soda drinks containing it were also popular. When its dangers became apparent and substitutes became available, its medical use went into decline, especially when, in the 1930s, amphetamine began to replace it for some purposes. Today its only generally accepted medical use is as a topical anesthetic in certain kinds of minor surgery and other clinical procedures. There are, however, some recent and so far uncertain signs of reviving interest in cocaine and even coca itself for other medical purposes, in research as well as in diagnosis and treatment.
Microwave‐Induced Rapid Access to Aromatic and Heteroaromatic Sulfonamides Under Solvent‐Free Conditions Without Using External Base

Abstract Microwave‐induced syntheses of sulfonamides, without using base under solvent‐free conditions, have been developed. The process finds its utility because of its simple operational procedure and high yields. Moreover, the process is fast and accommodative to different substituents on aromatic as well as heteroaromatic rings rendering sulfonamides (28 examples). #DRL‐Publication No. 327.
Ab initio study of the hydrogen-bonded complexes H2X⋯HY (X = O, S, Se: Y = F, Cl, Br)

Abstract Large basis set Gaussian orbital SCF-MO calculations are presented for the title molecules. Calculated equilibrium geometries, hydrogen bond dissociation energies and one-electron properties are presented to supplement available experimental data. Changes in electron distribution on complex formation are discussed in terms of Mulliken population analysis indices.
Effect of Stress on Water Diffusion in Silica Glass

The diffusion of water in silica glass was measured as a function of applied uniaxial stress and hydrostatic pressure at selected temperatures. It was found that the diffusion coefficient of water increased exponentially with increasing tensile stress and decreased with increasing compressive stress and increasing hydrostatic pressure. The activation volume for water diffusion in silica glass was found to be ∼170 cm3/mol at 192°C and ∼72 cm3/mol at 350°C. The solubility of water in glass showed a trend opposite to the diffusion coefficient, namely, it decreased exponentially with increasing tensile stress and increased with increasing compressive stress and hydrostatic pressure. These stress (or pressure) dependences were attributed to the shift of the glass-water reaction equilibrium.
Deuteron Magnetic Dipole Disintegration by 180° Electron Scattering

The magnetic dipole disintegration of the deuteron has been measured for excitation energies up to 16 MeV in the presence of relatively small electric multipole contributions by using a method of inelastic electron scattering at 180\ifmmode^\circ\else\textdegree\fi{}. Electrons of initial energy 41.5 MeV were magnetically deflected before and after scattering so that those scattered at 180\ifmmode^\circ\else\textdegree\fi{} entered a magnetic spectrometer set at 160\ifmmode^\circ\else\textdegree\fi{} with respect to the incident beam. The experimental cross sections measured relative to elastic scattering from the proton are higher than predicted by the electrodisintegration theory of Jankus. The discrepancy may be an indication of mesonic exchange currents which are not included in the Jankus theory.
Constraint coupling of force and motion between real and virtual mechanisms

In the approach presented in this research, a six DOF industrial manipulator is used as the master device to provide haptic feedback to the operator. In order develop effective constraints between the motion of the slave and master, a virtual manipulator concept is developed that couples the actual robotic kinematics with the constraints of the simulated slave manipulator. The position and velocity errors between the actual and virtual mechanisms are used to develop an optimal impedance controller that constrains the motion of the master in all directions that are orthogonal to the allowable motions of the slave. This approach allows the use of a conventional industrial manipulator as an effective haptic display device.
Archiving the relaxed consistency web

The historical, cultural, and intellectual importance of archiving the web has been widely recognized. Today, all countries with high Internet penetration rate have established high-profile archiving initiatives to crawl and archive the fast-disappearing web content for long-term use. As web technologies evolve, established web archiving techniques face challenges. This paper focuses on the potential impact of the relaxed consistency web design on crawler driven web archiving. Relaxed consistent websites may disseminate, albeit ephemerally, inaccurate and even contradictory information. If captured and preserved in the web archives as historical records, such information will degrade the overall archival quality. To assess the extent of such quality degradation, we build a simplified feed-following application and simulate its operation with synthetic workloads. The results indicate that a non-trivial portion of a relaxed consistency web archive may contain observable inconsistency, and the inconsistency window may extend significantly longer than that observed at the data store. We discuss the nature of such quality degradation and propose a few possible remedies.
In-Phase Error Estimation of Experimental Data and Optimal First Derivatives

The development of in-phase, a posteriori error estimates and the best functional representation for the solution and its derivative are examined. Several new and fundamental findings pertinent to both the experimentalist and analyst are presented. Applications requiring a high degree of precision such as associated with the defense, aerospace, and heat treatment arenas may benefit from these new findings. The basic framework involves the classical least-squares method, which is reexamined with the intent of 1) approximating local measurement errors necessary for estimating uncertainty and 2) predicting optimal solutions in both the primitive function and its derivative. With accurate local-error estimates, the initial data can be corrected by adding these estimates to the initial data to substantially reduce the root-mean-square error, that is, uncertainty. Additionally, the clarification between best curve fit and best prediction or solution is elucidated to provide insight into the meaning of a desirable resolution. The framework offered presents an elegant but practical method for approximating local measurement errors and for developing a functional representation of the desired function that best represents the solution in the presence of errorless data
Highly selective γ-lactone syntheses by intramolecular carbenoid carbon-hydrogen insertion in rhodium(II) carboxylate and rhodium(II) carboxamide catalyzed reactions of diazo esters

Abstract Rhodium(II) acetate and rhodium(II) acetamide catalyzed decomposition of diazo esters forms γ-lactones in high yield and with exceptionally high regio- and diastereoselectivity.
On the Solution of the Diffusion Equations by Numerical Methods

Finite difference method solution of diffusion equations, including analyses of stability and truncation errors
Moist convection in hydrogen atmospheres and the frequency of Saturn’s giant storms

A giant storm erupted on Saturn in December 2010. It produced intense lightning and cloud disturbances and encircled the planet in six months. Six giant storms—also called Great White Spots—have been observed on Saturn since 1876, recurring every 20 to 30 years and alternating between mid-latitudes and the equator. Here we use thermodynamic arguments to demonstrate that the quasi-periodic occurrence of Saturn’s giant storms can be explained by a water-loading mechanism, in which moist convection is suppressed for decades owing to the relatively large molecular weight of water in a hydrogen–helium atmosphere. We find that the interaction between moist convection and radiative cooling in the troposphere above the cloud base produces an oscillation that leads to giant storm generation with a period of approximately 60 years for either mid-latitudes or the equator, provided the mixing ratio of water vapour in the troposphere exceeds 1.0%. We use a two-dimensional axisymmetric dynamic model and a top-cooling convective adjustment scheme to apply our conceptual model to Saturn. For a water vapour mixing ratio of 1.1%, simulated storms show a recurrence interval, ammonia depletion and tropospheric warming that are consistent with 2010 observations. Jupiter’s atmosphere is more depleted in water than Saturn, which may explain its lack of planet-encircling storms.
Bandits with concave rewards and convex knapsacks

In this paper, we consider a very general model for exploration-exploitation tradeoff which allows arbitrary concave rewards and convex constraints on the decisions across time, in addition to the customary limitation on the time horizon. This model subsumes the classic multi-armed bandit (MAB) model, and the Bandits with Knapsacks (BwK) model of Badanidiyuru et al.[2013]. We also consider an extension of this model to allow linear contexts, similar to the linear contextual extension of the MAB model. We demonstrate that a natural and simple extension of the UCB family of algorithms for MAB provides a polynomial time algorithm that has near-optimal regret guarantees for this substantially more general model, and matches the bounds provided by Badanidiyuru et al.[2013] for the special case of BwK, which is quite surprising. We also provide computationally more efficient algorithms by establishing interesting connections between this problem and other well studied problems/algorithms such as the Blackwell approachability problem, online convex optimization, and the Frank-Wolfe technique for convex optimization. We give examples of several concrete applications, where this more general model of bandits allows for richer and/or more efficient formulations of the problem.
Synthesis of 2-alkylidenecyclopentanones via palladium-catalyzed carbopalladation/ring expansion of 1-(1-alkynyl)cyclobutanols.

The palladium-catalyzed cross-coupling of aryl halides or vinylic halides or triflates and 1-(1-alkynyl)cyclobutanols affords good yields of stereoisomerically pure 2-arylidene- or 2-(2-alkenylidene)cyclopentanones, respectively. The process involves (1) oxidative addition of the organic halide or triflate to Pd(0), (2) regioselective, intermolecular carbopalladation of the carbon−carbon triple bond of the 1-(1-alkynyl)cyclobutanol to produce a vinylic palladium intermediate, (3) regioselective ring expansion to a palladacycle, and (4) reductive elimination of the 2-alkylidenecyclopentanone with simultaneous regeneration of the Pd(0) catalyst. Generally, the best results are obtained by employing 10 mol % of Pd(OAc)2, 20 mol % of PPh3, 2 equiv of the aryl or vinylic iodide or vinylic triflate, 2 equiv of diisopropylethylamine, and n-Bu4NCl in DMF as the solvent.
Stimulus competition by inhibitory interference

When two stimuli are present in the receptive field of a V4 neuron, the firing rate response is between the weakest and strongest response elicited by each of the stimuli alone. When attention is directed towards the stimulus eliciting the strongest response (preferred stimulus), the response to the pair is increased, whereas the response decreases when attention is directed to the poor stimulus. We reproduced these results in a V4 model neuron. The model suggests that top-down attention biases the competition between V2 columns for control of V4 neurons by changing the relative timing of inhibition rather than by changes in synchrony of interneuron networks.
The phase transition in random horn satisfiability and its algorithmic implications

Let c > 0 be a constant, and Φ be a random Horn formula with n variables and m = c . 2n clauses, chosen uniformly at random (with repetition) from the set of all nonempty Horn clauses in the given variables. By analyzing PUR, a natural implementation of positive unit resolution, we show that limn→∞ Pr(Φ is satisfiable) = 1 - F(e-c), where F(x) = (1 - x)(1 - x2)(1 - x4) (1 - x8) .... Our method also yields as a byproduct an average-case analysis of this algorithm.
Stability Analysis of a Missile Control System with a Dynamic Inversion Controller

Examines the closed-loop stability of a bank-to-turn, air-to-air missile with a dynamic inversion controller using a two time-scale separation assumption. A state-space formulation for the /spl alpha/, /spl beta/, and /spl phi/ dynamics of the missile, assuming the inner-loop dynamic inversion is performed exactly, is presented. It is then shown that, under certain assumptions, the exponential stability of the /spl alpha/, /spl beta/, and /spl phi/ dynamics about the commanded values can be guaranteed if the inner loop design frequency is large enough. An example calculation of the required inner-loop frequency to guarantee stability is done for a particular bank-to-turn missile. Finally, nonlinear six degree-of-freedom simulation results of a maneuver performed with the dynamic inversion controller are presented.
The motivation to become an entrepreneur

Purpose – Since the 1950s, organizational psychology research investigating work‐related motivation has progressed from static content models to dynamic process models. Entrepreneurship research has evolved along a similar trajectory, adapting organizational psychology findings to better understand the motivation to become an entrepreneur. This paper reviews motivation research from both fields, explores some of the commonalities among current theories, and presents a new model of entrepreneurial motivation.Design/methodology/approach – In an exploratory study, the ability of tolerance for risk, perceived feasibility, and perceived net desirability to predict intentions for self‐employment is examined in a sample of 114 undergraduate business students at Florida Gulf Coast University.Findings – Results indicated that tolerance for risk, perceived feasibility and net desirability significantly predicted self‐employment intentions, with an adjusted R2 of 0.528.Research limitations/implications – Because the...
Comparative study of peptide-type antibiotics in reversed-phase thin-layer chromatography and reversed-phase high-performance liquid chromatography

Abstract Reversed-phase thin-layer chromatographic (RP-TLC) conditions were investigated for nineteen peptide-type antibiotics, with molecular weights between 102 and 25,000 and of different chemical characteristics, to find mobile phases giving RF values between 0.05 and 0.95. For this purpose, 27 different mobile phases were employed, representing three organic modifiers, three buffers and three pH values. The suitability of these RP-TLC mobile phases for reversed-phase high-performance liquid chromatography (RP-HPLC) was then investigated. With no or only slight modification of the RP-TLC mobile phases, reasonable tR values were obtained for the same antibiotics, using a Vydac C18 RP-HPLC column. It is suggested that these developed systems are applicable for other peptide antibiotics not tested in this study. However, no empirical correlations between molecular weights, RF, theoretical plate height or plate number could be detected.
General synthesis of 2-alkyn-1-ylboronates in excellent isomeric purity

Abstract 2-Alkyn-1-ylboronates have been synthesized successfully, in excellent isomeric purity, via the in situ homologation of alkyn-1-ylboronates with LiCH 2 I. The relative reactivities exhibited by various LiCH 2 X reagents (X=Cl; Br; I) are described.
Effects of large area liquid lithium limiters on spherical torus plasmas

Use of a large-area liquid lithium surface as a limiter has significantly improved the plasma performance in the Current Drive Experiment-Upgrade (CDX-U) at the Princeton Plasma Physics Laboratory. Previous CDX-U experiments with a partially-covered toroidal lithium limiter tray have shown a decrease in impurities and the recycling of hydrogenic species. Improvements in loading techniques have permitted nearly full coverage of the tray surface with liquid lithium. Under these conditions, there was a large drop in the loop voltage needed to sustain the plasma current. The data are consistent with simulations that indicate more stable plasmas having broader current profiles, higher temperatures, and lowered impurities with liquid lithium walls. As further evidence for reduced recycling with a liquid lithium limiter, the gas puffing had to be increased by up to a factor of eight for the same plasma density achieved with an empty toroidal tray limiter.
Symmetry Behavior at Finite Temperature

Spontaneous symmetry breaking at finite temperature is studied. We show that for the class of theories discussed, symmetry is restored above a critical temperature ${{\ensuremath{\beta}}_{c}}^{\ensuremath{-}1}$. We determine ${\ensuremath{\beta}}_{c}$ by a functional-diagrammatic evaluation of the effective potential and the effective mass. A formula for ${\ensuremath{\beta}}_{c}$ is obtained in terms of the renormalized parameters of the theory. By examining a large subset of graphs, we show that the formula is accurate for weak coupling. An approximate gap equation is derived whose solutions describe the theory near the critical point. For gauge theories, special attention is given to ensure gauge invariance of physical quantities. When symmetry is violated dynamically, it is argued that no critical point exists.
Formation of macrocycles via ring-closing olefin metathesis.

The enhanced metathesis activity of 1,3-dimesityl-4,5-dihydroimidazole-2-ylidene ruthenium carbene catalyst 3 significantly increases the feasibility of synthesizing macrocyclic compounds. Catalyst 3 exhibits sufficient activity in RCM to dimerize α,β-unsaturated ester substrates and afford the corresponding head-to-tail (E,E)-dimeric (and trimeric) macrocycles. The dimerization appears to be under thermodynamic control with the product mixture dependent not only on the electronic and steric nature of the substrate but also on concentration.
SQUARES OF CHARACTERS AND FINITE GROUPS

Abstract Let G be a finite group and χ be an irreducible complex character. We study the character χ 2 in the case that χ ( 1 ) is a prime power.
Feedback coupled resource allocation policies in the multiprogramming-multiprocessor computer system

Model studies of some integrated, feedback-driven scheduling systems for multiprogrammed-multiprocessor computer systems are presented. The basic control variables used are the data-flow rates for the processes executing on the CPU. The model systems feature simulated continuous-flow and preempt-resume scheduling of input-output activity. Attention is given to the amount of memory resource required for effective processing of the I/O activity (buffer space assignment). The model studies used both distribution-driven and trace-driven techniques. Even relatively simple dynamic schedulers are shown to improve system performance (as measured by user CPU time) over that given by optimal or near-optimal static schedulers imbedded in identical system structures and workload environments. The improvement is greatest under a heavy I/O demand workload.
Neutron diffraction studies on transition metal hydride complexes

Recent neutron diffraction investigations on terminal, bridging and triply-bridging metal-hydrogen bonds are reviewed.