cssi/SciSciGPT-SciSciNet huggingface dataset:
Hall normalization constants for the Bures volumes of the n-state quantum systems

We report the results of certain integrations of quantum-theoretic interest, relying, in this regard, upon recently developed parametrizations of Boya et al (1998 Preprint quant-ph/9810084) of the n × n density matrices, in terms of squared components of the unit (n - 1)-sphere and the n × n unitary matrices. Firstly, we express the normalized volume elements of the Bures (minimal monotone) metric for n = 2 and 3, thereby obtaining `Bures prior probability distributions' over the two- and three-state systems. Then, as a first step in extending these results to n>3, we determine that the `Hall normalization constant' (Cn) for the marginal Bures prior probablity distribution over the (n - 1)-dimensional simplex of the n eigenvalues of the n × n density matrices is, for n = 4, equal to 71 680/2. Since we also find that C3 = 35/, it follows that C4 is simply equal to 211C3/. (C2 itself is known to equal 2/.) The constant C5 is also found. It too is associated with a remarkably simple decomposition, involving the product of the eight consecutive prime numbers from 3 to 23. We also preliminarily investigate several cases n>5, with the use of quasi-Monte Carlo integration. We hope that the various analyses reported will prove useful in deriving a general formula (which evidence suggests will involve the Bernoulli numbers) for the Hall normalization constant for arbitrary n. This would have diverse applications, including quantum inference and universal quantum coding.
Estimating Bias Error Distributions

In this article we formulate a general methodology for estimating the bias error distribution of a device in a measurement domain from less accurate measurements when a minimal number of standard values (typically no more than two values) are available. A new perspective is that the bias error distribution can be found as a solution of an intrinsic functional equation in a domain. Based on this theory, the scaling- and translation-based methods for determining the bias error distribution are developed. These methods are applicable to virtually any device as long as the bias error distribution of the device can be sufficiently described by a power series (a polynomial) or a Fourier series in a domain. These methods were validated through computational simulations and laboratory calibration experiments for a number of different devices.
Optimally Directed Truss Topology Generation Using Shape Annealing

Abstract: "This paper presents a technique for the generation and optimization of truss structure topologies based on the shape annealing algorithm. Feasible topologies for the truss are generated through a shape grammar, in an optimally directed manner, using simulated annealing. The algorithm can incorporate stress and buckling constraints as well as assembly and manufacturing constraints, during design topology generation."
Ricardian comparative advantage with intermediate inputs

Abstract This paper examines the role of comparative advantage in a Ricardian trade model with intermediate inputs. The main issue is how to define comparative advantage when there are intermediate inputs. Several definitions are suggested, differing in whether they are based on the total costs of producing goods, on the one hand, or on the labor requirements per dollar of value added, on the other; and differing also – since both approaches require prices of intermediate inputs – in the choice of prices for making these comparisons. Standard “predictions” of trade patterns in terms of comparative advantage are easily derived, but using the value-added definition and actual prices that prevail with trade. These have the usual implications for patterns of specialization based on rankings, or “chains,” of comparative advantage. However, because these prices are not given and may depend on barriers to trade, these comparisons are less informative than in Ricardian models with only final goods. In fact, trade patterns here can be so sensitive to trade costs that any such comparison predicting the trade in particular goods fails to be robust. In spite of this, the gains from trade are unambiguous in these Ricardian models, with imported inputs actually providing an additional source of gain from trade. Also, a weaker statement of the Law of Comparative Advantage, using only a correlation or average relationship between relative autarky prices and trade, is valid under weaker assumptions than in more general models.
A case study in intelligent vs. conventional control for a process control experiment

Abstract While intelligent control methods such as direct, adaptive, and supervisory fuzzy control have shown some success, there is a significant need to evaluate their performance relative to conventional control approaches, particularly in an experimental setting. Such evaluations help to determine the value of the new intelligent control methods, and provide the engineer with general guidelines on how to apply them to more complex real-world applications. In this work a case study is conducted where comparisons are made between conventional and intelligent controllers for a process control experiment in our laboratory. Nominal, disturbance, and plant failure conditions are studied and the advantages and disadvantages of each of the approaches is highlighted.
Fitting variogram models by weighted least squares

The method of weighted least squares is shown to be an appropriate way of fitting variogram models. The weighting scheme automatically gives most weight to early lags and down-weights those lags with a small number of pairs. Although weights are derived assuming the data are Gaussian (normal), they are shown to be still appropriate in the setting where data are a (smooth) transform of the Gaussian case. The method of (iterated) generalized least squares, which takes into account correlation between variogram estimators at different lags, offer more statistical efficiency at the price of more complexity. Weighted least squares for the robust estimator, based on square root differences, is less of a compromise.
Tolerating faults in a mesh with a row of spare nodes

We present an efficient method for tolerating faults in a two-dimensional mesh architecture. Our approach is based on adding spare components (nodes) and extra links (edges) such that the resulting architecture can be reconfigured as a mesh in the presence of faults. We optimize the cost of the fault-tolerant mesh architecture by adding about one row of redundant nodes in addition to a set of k spare nodes (while tolerating up to k node faults) and minimizing the number of links per node. Our results are surprisingly efficient and seem to practical for small values of k. The degree of the fault-tolerant architecture is k + 5 for odd k, and k+6 for even k. Our results can be generalized to d-dimensional meshes.
Wave Engine Aerothermodynamic Design

A method for aerothermodynamic preliminary design of a wave engine is presented. The engine has a centrifugal precompressor for the wave rotor which feeds high and low pressure turbines. Three specific wave engine designs are presented. Wave rotor blades are naturally cooled by the ingested air; thus combustion temperatures can be as high as 1900°K. Engine pressure ratios of over 25 are obtained in compact designs. It is shown that no nozzles at the end of the rotor blade passages yield the highest cycle efficiencies which can be over 50%. Rotor blades are straight and easily milled, cast or fabricated.Copyright © 1991 by ASME
Single-call mechanisms

Truthfulness is fragile and demanding. It is oftentimes harder to guarantee truthfulness when solving a problem than it is to solve the problem itself. Even worse, truthfulness can be utterly destroyed by small uncertainties in a mechanism’s outcome. One obstacle is that truthful payments depend on outcomes other than the one realized, such as the lengths of non-shortest-paths in a shortest-path auction. Single-call mechanisms are a powerful tool that circumvents this obstacle: they implicitly charge truthful payments, guaranteeing truthfulness in expectation using only the outcome realized by the mechanism. The cost of such truthfulness is a trade-off between the expected quality of the outcome and the risk of large payments. We study two of the most general domains for truthful mechanisms and largely settle when and to what extent single-call mechanisms are possible. The first single-call construction was discovered by Babaioff et al. [2010] in single-parameter domains. They give a transformation that turns any monotone, single-parameter allocation rule into a truthful-in-expectation single-call mechanism. Our first result is a natural complement to Babaioff et al. [2010]: we give a new transformation that produces a single-call VCG mechanism from any allocation rule for which VCG payments are truthful. Second, in both the single-parameter and VCG settings, we precisely characterize the possible transformations, showing that a wide variety of transformations are possible but that all take a very simple form. Finally, we study the inherent trade-off between the expected quality of the outcome and the risk of large payments. We show that our construction and that of Babaioff et al. [2010] simultaneously optimize a variety of metrics in their respective domains. Our study is motivated by settings where uncertainty in a mechanism renders other known techniques untruthful, and we offer a variety of examples where such uncertainty can arise. In particular, we analyze pay-per-click advertising auctions, where the truthfulness of the standard VCG-based auction is easily broken when the auctioneer’s estimated click-through-rates are imprecise.
Redefining the survival of the fittest: communication disorders in the 21st century.

Objectives: To determine the economic effect on the US economy of the cost of caring for people with communication disorders as well as the cost of lost or degraded employment opportunities for people with such disorders, including disorders of hearing, voice, speech, and language. Study Design: Survey of available historical and contemporary governmental and scholarly data concerning work force distribution and the epidemiology of disorders of hearing, voice, speech, and language. Method: Analysis of epidemiological and economic data for industrialized countries, North America, and the United States. Results: Communication disorders are estimated to have a prevalence of 5% to 10%. People with communication disorders may be more economically disadvantaged than those with less severe disabilities. The data suggest that people with severe speech disabilities are more often found to be unemployed or in a lower economic class than people with hearing loss or other disabilities. Communication disorders may cost the United States from $154 billion to $186 billion per year, which is equal to 2.5% to 3% of the Gross National Product. Conclusions: Communication disorders reduce the economic output of the United States, whose economy has become dependent on communication-based employment. This trend will increase during the next century. The economic cost and the prevalence rates of communication disorders in the United States indicate that they will be a major public health challenge for the 21st century.
ALEXANDER QUANDLES OF ORDER 16

Isomorphism classes of Alexander quandles of order 16 are determined, and classes of connected quandles are identified. This paper extends the list of distinct connected finite Alexander quandles.
Nonlinear aerodynamic modeling of flap oscillations in transonic flow - A numerical validation

The regime of validity of a nonlinear aerodynamic force and moment formulation, based on concepts from nonlinear functional analysis and applicable to a transonic airfoil with a deflecting flap, is investigated. A time-dependent finite difference technique is used to evaluate the aerodynamic data of the formulation in terms of specified, characteristic motions. Flap-motion histories are generated from the flap inertial equations of motion, with aerodynamic reactions specified by the moment formulation. The motion histories depicting the cases of decaying and growing flap oscillations are compared with histories generated through simultaneous, coupled solution of the fluid-dynamic equations and flap inertial equations of motion. The range of applicability of the formulation is discussed.
Rises, Trenches, Great Faults and Crustal Blocks

The transform fault concept is extended to a spherical surface. The earth's surface is considered to be made of a number of rigid crustal blocks. It is assumed that each block is bounded by rises (where new surface is formed), trenches or young fold mountains (where surface is being destroyed), and great faults, and that there is no stretching, folding, or distortion of any kind within a given block. On a spherical surface, the motion of one block (over the mantle) relative to another block may then be described by a rotation of one block relative to the other block. This rotation requires three parameters, two to locate the pole of relative rotation and one to specify the magnitude of the angular velocity. If two adjacent blocks have as common boundaries a number of great faults, all of these faults must lie on ‘circles of latitude’ about the pole of relative rotation. The velocity of one block relative to the other must vary along their common boundary; this velocity would have a maximum at the ‘equator’ and would vanish at a pole of relative rotation. The motion of Africa relative to South America is a case for which enough data are available to critically test this hypothesis. The many offsets on the mid-Atlantic ridge appear to be compatible with a pole of relative rotation at 62°N (±5°), 36°W (±2°). The velocity pattern predicted by this choice of pole roughly agrees with the spreading velocities determined from magnetic anomalies. The motion of the Pacific block relative to North America is also examined. The strike of faults from the Gulf of California to Alaska and the angles inferred from earthquake mechanism solutions both imply a pole of relative rotation at 53°N (±3°), 53°W (±5°). The spreading of the Pacific-Antarctic ridge shows the best agreement with this hypothesis. The Antarctic block is found to be moving relative to the Pacific block about a pole at 71°S (±2°), 118°E (±5°) with a maximum spreading rate of 5.7 (±0.2) cm/yr. An estimate of the motion of the Antarctic block relative to Africa is made by assuming closure of the Africa-America-Pacific-Antarctica-Africa circuit and summing the three angular velocity vectors for the cases above.
Growth and instability of the liquid rim in the crown splash regime

We study the formation, growth and disintegration of jets following the impact of a drop on a thin film of the same liquid for and using a combination of numerical simulations and linear stability theory (Agbaglah, Josserand & Zaleski, Phys. Fluids, vol. 25, 2013, 022103). Our simulations faithfully capture this phenomena and are in good agreement with experimental profiles obtained from high-speed X-ray imaging. We obtain scaling relations from our simulations and use these as inputs to our stability analysis. The resulting predictions for the most unstable wavelength are in excellent agreement with experimental data. Our calculations show that the dominant destabilizing mechanism is a competition between capillarity and inertia but that deceleration of the rim provides an additional boost to growth. We also predict over the entire parameter range of our study the number and timescale for formation of secondary droplets formed during a splash, based on the assumption that the most unstable mode sets the droplet number.
Scattering theory of nonlinear thermoelectricity in quantum coherent conductors

We construct a scattering theory of weakly nonlinear thermoelectric transport through sub-micron scale conductors. The theory incorporates the leading nonlinear contributions in temperature and voltage biases to the charge and heat currents. Because of the finite capacitances of sub-micron scale conducting circuits, fundamental conservation laws such as gauge invariance and current conservation require special care to be preserved. We do this by extending the approach of Christen and Buttiker (1996 Europhys. Lett. 35 523) to coupled charge and heat transport. In this way we write relations connecting nonlinear transport coefficients in a manner similar to Mott’s relation between the linear thermopower and the linear conductance. We derive sum rules that nonlinear transport coefficients must satisfy to preserve gauge invariance and current conservation. We illustrate our theory by calculating the efficiency of heat engines and the coefficient of performance of thermoelectric refrigerators based on quantum point contacts and resonant tunneling barriers. We identify, in particular, rectification effects that increase device performance.
Improving the electrical conductivity of composites comprised of short conducting fibers in a nonconducting matrix: the addition of a nonconducting particulate filler

The addition of a second discontinuous filler (silica fume) that is essentially nonconducting to a composite with a comparably nonconducting matrix (cement) and a conducting discontinuous filler (carbon fibers) was found to increase the electrical conductivity of the composite when the conducting filler volume fraction was less than 3.2%. The maximum conducting filler volume fraction for the second filler to be effective was only 0.5% when the second filler was sand, which was much coarser than silica fume. The improved conductivity due to the presence of the second filler is due to the improved dispersion of the conducting filler. The silica fume addition did not affect the percolation threshold, but the sand addition increased the threshold.
High performance robust linear controller synthesis for an induction motor using a multi-objective hybrid control strategy

Abstract A robust induction motor control should provide the desired performance in the face of both plant model and controller model uncertainty. In a recent work, Bottura and co-workers, using the field orientation principle, introduced a representation of a nonlinear time-varying induction motor model that admits robust induction motor controller synthesis in the linear H ∞ framework. The present work considers the use of the approach of Bottura et al. for attaining robust performance of the main operating modes–tracking and disturbance rejection–of an induction motor control system under implementation constraints on the control signal magnitude. This approach requires two distinct mode-specific controllers with gains that cannot be bridged without considerable performance degradation. To address this problem, a multi-objective hybrid control design methodology is developed that employs the corresponding mode-specific controller in each mode, and organizes a rapid and smooth steady-state switching, or transfer, between these controllers to permit sequencing of the operating modes, as necessary. Simulation shows that the technique proposed yields controllers with performance minimally affected by an imprecise modeling of an induction motor, as well as a reduced cost controller implementation throughout the entire induction motor operating sequence.
Isometries of Hilbert space valued function spaces

Let $X$ be a (real or complex) rearrangement-in\-va\-riant function space on $\Om$ (where $\Om = [0,1]$ or $\Om \subseteq \bbN$) whose norm is not proportional to the $L_2$-norm. Let $H$ be a separable Hilbert space. We characterize surjective isometries of $X(H).$ We prove that if $T$ is such an isometry then there exist Borel maps $a:\Om\to\bbK$ and $\sigma:\Om\lra\Om$ and a strongly measurable operator map $S$ of $\Om$ into $\calB(H)$ so that for almost all $\om$ $S(\om)$ is a surjective isometry of $H$ and for any $f\in X(H)$ $$Tf(\om)=a(\om)S(\om)(f(\sigma(\om))) \text{ a.e.}$$ As a consequence we obtain a new proof of characterization of surjective isometries in complex rearrangement-invariant function spaces.
ROSAT X-Ray Colors and Emission Mechanisms in Early-Type Galaxies

The X-ray colors and X-ray-to-optical luminosity ratios (LX/LB) of 61 early-type galaxies observed with the ROSAT PSPC are determined. The colors indicate that the X-ray spectral properties of galaxies vary as a function of LX/LB. The brightest X-ray galaxies have colors that are consistent with thermal emission from hot gas with roughly the same metallicity of 50% solar. The spatial variation of the colors indicates that the gas temperature in these galaxies increases radially. Galaxies with medium LX/LB also have spectral properties consistent with emission from hot gas. If a simple one-component thermal model is assumed to describe the 0.1-2.0 keV X-ray emission in these galaxies, then one possible explanation for the progressive decrease in LX/LB among galaxies of this class could be the progressive decrease in metal abundance of the X-ray-emitting gas contained by the galaxies. However, stellar X-ray emission may become a complicating factor for the fainter galaxies in this medium-LX/LB class. Galaxies with the lowest LX/LB values appear to be lacking a hot interstellar component. Their X-ray colors are consistent with those derived from the bulges of the spiral galaxies M31 and NGC 1291. In M31, the X-ray emission is resolved into discrete sources and is apparently due primarily to low-mass X-ray binaries (LMXBs). We therefore suggest that the bulk of the X-ray emission in the faintest elliptical galaxies is also due to LMXBs. Previously, the X-ray spectra of X-ray-faint galaxies had been found to be described by a hard component, which was attributed to LMXB emission, and a very soft component of unknown origin. We show that the very soft component also likely results from LMXBs, as a very soft component is seen in the X-ray spectra of the nearby LMXB Her X-1 and LMXBs in the bulge of M31. If the X-ray emission in X-ray-faint galaxies is primarily from stellar sources, then a range in LX/LB among these galaxies suggests that the stellar X-ray luminosity does not scale with optical luminosity, at least for galaxies of low optical luminosities. This could be the result of a decrease in the proportion of LMXBs with decreasing optical luminosity and/or the effects of fluctuations in the small number of LMXBs expected.
An Unusual Radio Galaxy in Abell 428: A Large, Powerful FR I Source in a Disk-dominated Host

We report the discovery of a powerful (~1024 h−275 WHz−1 at 20 cm) FR I radio source in a highly flattened disk-dominated galaxy. Half the radio flux from this source is concentrated within the host galaxy, with the remainder in a pair of nearly symmetrical lobes of total extent ~200 kpc nearly perpendicular to the disk. Traditional wisdom maintains that powerful, extended radio sources are found only in ellipticals or recent merger events. We report B, R, J, and K imaging, optical spectroscopy, a rotation curve, an IRAS detection, and a VLA 20 cm image for this galaxy, 0313-192. The optical and near-infrared images clearly show a disk. We detect apparent spiral arms in a deep B-band exposure, and a dust lane from a higher resolution B-band image. The reddened nucleus is consistent with extinction by a similar dust lane. The optical spectrum suggests a central AGN and shows some evidence of a starburst, with both the AGN and central starlight appearing substantially reddened (perhaps by the optical dust lane). From analysis of the extended line emission in [O III] and Hα, we derive a rotation curve consistent with an early-type, dusty spiral seen edge-on. From the IRAS detection at 60 and 100 μm, we find that the ratio of far-infrared to radio flux places this object firmly as a radio galaxy (i.e., the radio emission is not powered by star formation). The radio structure suggests that the radio source in this galaxy is related to the same physical mechanisms that are present in jet-fed powerful radio sources, and that such powerful, extended sources can (albeit extremely rarely) occur in a disk-dominated host.
A THREE-DIMENSIONAL INTEGRAL METHOD FOR CALCULATING INCOMPRESSIBLE TURBULENT SKIN FRICTION.

A new integral method is proposed for the analysis of three-dimensional incompressible turbulent boundary layers. The method utilizes velocity profile expressions in wall-law form to derive two coupled partial differential equations for the two components of surface skin friction. No shape factors or emprical shear stress correlations are needed in the method. The only requirements are a knowledge of the external velocity and streamline distribution and initial values of skin friction along a starting crossflow line of the flow. The method is insensitive to sidewall conditions and may be continued downstream until the complete three-dimensional separation line of the flow has been computed. Two comparisons with experiment are shown a curved-duct unseparated flow and a T-shaped-box separated flow. The calculations are very straightforward and agree reasonable well with the data for friction, crossflow angle, and separation line.
Managerial motivation and timing of open market share repurchases

There are two major mechanisms by which managers distribute cash to shareholders: through dividends and share repurchases. Historically, dividends have been the preferred method, but in recent years, share repurchases have become more popular, with more firms using repurchases than dividends to distribute cash. During the sample period of 2004–2006, 6.5 billion shares were repurchased for a total dollar volume amount of $222 billion. Using a unique dataset on actual monthly share repurchases, this paper investigates when and why managers repurchase shares in the open market. The paper finds evidence that firms which make repurchases are jointly timing their repurchases to perceived undervaluation and the presence of discretionary cash flow. In addition, the paper finds evidence which supports that (1) firms in competitive industries tend to repurchase less, (2) firms tend to substitute repurchases for anti-takeover provision adoption, and (3) firms attempt to manage earnings upward through the use of repurchases.
Inhibition of Isolation-Induced Attack behavior of Mice by Drugs

Three dose-response experiments indicated that psilocybin, mescaline, and 2-brom-lysergic acid diethylamide (BOL-148) inhibited isolation-induced attack behavior of 11-week-old Swiss-Webster mice, tested at the time of peak effect. The 3 dose-response curves show that the per cent inhibitory effects of these compounds are increasing monotonic functions of dose. The ED 50 and confidence limits for psilocybin, mescaline, and BOL-148 are 2.096 mg./Kg. (1.334–3.291), 5.413 mg./Kg. (2.904–10.090), and 1.183 mg./Kg. (0.676–2.069), respectively.
Vanadium-catalyzed oxidative Strecker reaction: α-C–H cyanation of para-methoxyphenyl (PMP)-protected primary amines

We describe an oxidative Strecker reaction that allows for direct cyanation of para-methoxyphenyl (PMP)-protected primary amines. A vanadium(V) complex was used as the catalyst and TBHP as the oxidant. The cyanation occurs at the α-C position bearing either an alkyl or an aromatic group. This method provides a direct access to α-aminonitrile from amines with one-carbon extension.
Detection of Substructure in the Gravitationally Lensed Quasar MG0414+0534 Using Mid-infrared and Radio VLBI Observations

We present 11.2 {mu}m observations of the gravitationally lensed, radio-loud z{sub s} = 2.64 quasar MG0414+0534, obtained using the Michelle camera on Gemini North. We find a flux ratio anomaly of A2/A1 = 0.93 {+-} 0.02 for the quasar images A1 and A2. When combined with the 11.7 {mu}m measurements from Minezaki et al., the A2/A1 flux ratio is nearly 5{sigma} from the expected ratio for a model based on the two visible lens galaxies. The mid-IR flux ratio anomaly can be explained by a satellite (substructure), 0.''3 northeast of image A2, as can the detailed very long baseline interferometry (VLBI) structures of the jet produced by the quasar. When we combine the mid-IR flux ratios with high-resolution VLBI measurements, we find a best-fit mass between 10{sup 6.2} and 10{sup 7.5} M{sub Sun} inside the Einstein radius for a satellite substructure modeled as a singular isothermal sphere at the redshift of the main lens (z{sub l} = 0.96). We are unable to set an interesting limit on the mass to light ratio due to its proximity to the quasar image A2. While the observations used here were technically difficult, surveys of flux anomalies in gravitational lenses with the James Webbmore » Space Telescope will be simple, fast, and should well constrain the abundance of substructure in dark matter halos.« less
Osmotic and ionic regulation in polar fishes

Abstract Serum ion concentrations increase in marine fishes and decrease in freshwater species as environmental temperature is lowered. Measurements from Antarctic fishes at temperatures near the freezing point of sea water show some of the highest serum ion concentrations and osmolarities found in anisosmotic fishes. Three species of Antarctic fishes were subjected to hyperosmotic and hypoosmotic conditions to determine to what extent these fish osmoregulate, and if intracellular isosmotic regulation serves as a means of compensation for the high serum osmolarities and ion concentrations observed in Antarctic fishes. The results indicate that Trematomus borchgrevinki Boulenger, T. nicolai Boulenger, and T. bernacchii Boulenger can effectively osmoregulate over a range of 500 to 1750 mOsm. Although these fish experience little change in environmental salinity under normal conditions, this finding indicates that the mechanisms responsible for anisosmotic regulation are intact in these fish. Intracellular ion concentrations and free amino acid determinations show that free amino acids do not serve as intracellular osmotic effectors within the muscles of T. borchgrevinki or T. bernacchii. It appears that osmotic balance is achieved by higher intracellular sodium and potassium concentrations in comparison with temperate water marine fishes.
This is SPIRAL-TAP: Sparse Poisson Intensity Reconstruction ALgorithms—Theory and Practice

Observations in many applications consist of counts of discrete events, such as photons hitting a detector, which cannot be effectively modeled using an additive bounded or Gaussian noise model, and instead require a Poisson noise model. As a result, accurate reconstruction of a spatially or temporally distributed phenomenon (f*) from Poisson data (y) cannot be effectively accomplished by minimizing a conventional penalized least-squares objective function. The problem addressed in this paper is the estimation of f* from y in an inverse problem setting, where the number of unknowns may potentially be larger than the number of observations and f* admits sparse approximation. The optimization formulation considered in this paper uses a penalized negative Poisson log-likelihood objective function with nonnegativity constraints (since Poisson intensities are naturally nonnegative). In particular, the proposed approach incorporates key ideas of using separable quadratic approximations to the objective function at each iteration and penalization terms related to l1 norms of coefficient vectors, total variation seminorms, and partition-based multiscale estimation methods.
Analysis of low Reynolds number airfoil flows

Compressible steady and unsteady flowfields over a NACA 0012 airfoil at transitional Reynolds numbers are investigated. Comparisons with recently obtained experimental data are used to evaluate the ability of a numerical solution based on the compressible thin layer Navier-Stokes approximation, augmented with a transition model, to simulate transitional flow features. The discretization is obtained with an upwind-biased, factorized, iterative scheme. Transition onset is estimated using an empirical criterion based on the computed mean flow boundary- layer quantities. The transition length is computed from an empirical formula. The incorporation of transition modeling enables the prediction of the experimentally observed leading-edge separation bubbles. Results for steady airfoil flows at fixed angles of attack and for oscillating airfoils are presented. HE prediction of steady, inviscid flows over aerodynamic configurations is performed routinely nowadays. The computation of flows with separation bubbles or of fully sep- arated flows, on the other hand, is still a very challenging problem. For many practical applications, the assumption of fully developed turbulent flow yields good predictions of the flowfield. In other circumstances, such as the leading-edge dynamic stall flow, this assumption is not valid and compu- tations of such flows need improved methods. A characteristic feature of the dynamic stall flow is the onset of compressibility effects at a very low freestream Mach num- ber of O.2. 1-2 In addition, at transitional Reynolds numbers, it has been shown3-4 that the dynamic stall events are closely governed by the formation of a laminar separation bubble and its subsequent bursting. In fact, the above-cited studies demonstrate that the failure of the separated shear layer to reattach initiates dynamic stall, leading to the formation of the dynamic stall vortex. Further complications arise when the locally supersonic flow forms shocks that interact with the local boundary layer. It is important to recognize that the scales of the flow are very small here and the flow physics is not very clear. It is obvious that an accurate computational study of the problem demands a proper modeling of the phys- ics of the local compressible flow. In an effort to reach this eventual goal, it is necessary to include the transition physics that plays a key role in the dynamic stall process. The study to be reported represents a step in this direction. It is well known that prediction of the transition point and the transition length in such strongly adverse pressure gradient driven flows with current methods is difficult and involves uncertainties. Although several methods are available, the engineering prediction of transition relies on empirical for- mulation for boundary-layer flows. Whereas these methods have been moderately successful in steady and subsonic flows,
Global existence of weak solutions to the FENE dumbbell model of polymeric flows

Systems coupling fluids and polymers are of great interest in many branches of sciences. One of the most classical models to describe them is the FENE (Finite Extensible Nonlinear Elastic) dumbbell model. We prove global existence of weak solutions to the FENE dumbbell model of polymeric flows. The main difficulty is the passage to the limit in a nonlinear term that has no obvious compactness properties. The proof uses many weak convergence techniques. In particular it is based on the control of the propagation of strong convergence of some well chosen quantity by studying a transport equation for its defect measure. In addition, this quantity controls a rescaled defect measure of the gradient of the velocity.
The synthesis of functional polyphosphazenes and their surfaces

The macromolecular substitution approach for the synthesis of polyphosphazenes provides access to many different polymers. However, it precludes the use of reagents that contain two or more functional groups because such compounds would cause extensive crosslinking of the chains. This presents a problem because many of the uses for which polyphosphazenes seem ideally suited require the presence of -OH, -COOH, -NH2, -SO3H, -PR2 and other functional units in the side-chain structure. We have developed two approaches to introduce such active sites: (1) protection‐deprotection reactions; and (2) direct reactions of active reagents with the organic side-groups of non-functional poly(organophosphazenes). These methods have been applied both at the molecular level and in the form of reactions carried out only at polymer surfaces. The resultant polymers have special properties that are valuable in the microencapsulation of sensitive biological agents; in the formation of hydrophobic, hydrophilic, or adhesive surfaces; in crosslinking reactions; and in the development of solid polymer electrolytes, bio-erodible polymers, pH-triggered hydrogels, polymer blends and interpenetrating polymer networks. Overall, more than 700 different polyphosphazenes are now known, and a large number of these are functional macromolecules targeted for specific property combinations and uses. # 1998 John Wiley & Sons, Ltd.
Limitations of the boundary-layer equations for predicting laminar symmetric sudden expansion flows

A finite-difference solution scheme is used to study the limitations and capabilities of the boundary-layer equation model for flow through abrupt, symmetric expansions. Solutions of the boundary-layer equations are compared with previous numerical predictions and experimental measurements. Some flow parameters are not well predicted for Reynolds numbers below 200. Global iteration over the flow field to include upstream effects does not significantly influence the predictions. Axisymmetric and two-dimensional flows are investigated. The effect of initial conditions is discussed.
Local stochastic non-Gaussianity and N-body simulations

Large-scale clustering of highly biased tracers of large-scale structure has emerged as one of the best observational probes of primordial non-Gaussianity of the local type (i.e. f{sub NL}{sup local}). This type of non-Gaussianity can be generated in multifield models of inflation such as the curvaton model. Recently, Tseliakhovich, Hirata, and Slosar showed that the clustering statistics depend qualitatively on the ratio of inflaton to curvaton power ξ after reheating, a free parameter of the model. If ξ is significantly different from zero, so that the inflaton makes a non-negligible contribution to the primordial adiabatic curvature, then the peak-background split ansatz predicts that the halo bias will be stochastic on large scales. In this paper, we test this prediction in N-body simulations. We find that large-scale stochasticity is generated, in qualitative agreement with the prediction, but that the level of stochasticity is overpredicted by ≈ 30%. Other predictions, such as ξ independence of the halo bias, are confirmed by the simulations. Surprisingly, even in the Gaussian case we do not find that halo model predictions for stochasticity agree consistently with simulations, suggesting that semi-analytic modeling of stochasticity is generally more difficult than modeling halo bias.
Physical database design: A DSS approach

Abstract This paper presents a working decision support system for use in the physical design of a database. Physical database design, a structured decision problem, lends itself to a decision support approach because closed form algorithms are computationally infeasible. The paper describes the physical database design problem, presents an overview of a software system for use in solving this problem, and evaluates the use of the system in solving a sample problem.
(2+2+1) Cycloadditions of ynol ethers. The synthesis of iron complexes of 3-alkoxycyclopentadienones

Abstract This Letter reports the synthesis of iron complexes of 3-oxocyclopentadienones from ynol ether–alkyne [2+2+1] cycloaddition reactions as well as the use of 3-alkoxycyclopentadienones in subsequent cycloaddition reactions.
Regulation of retinal inflammation by rhythmic expression of MiR-146a in diabetic retina.

Purpose Chronic inflammation and dysregulation of circadian rhythmicity are involved in the pathogenesis of diabetic retinopathy. MicroRNAs (miRNAs) can regulate inflammation and circadian clock machinery. We tested the hypothesis that altered daily rhythm of miR-146a expression in diabetes contributes to retinal inflammation. Methods Nondiabetic and STZ-induced diabetic rats kept in 12/12 light/dark cycle were killed every 2 hours over a 72-hour period. Human retinal endothelial cells (HRECs) were synchronized with dexamethasone. Expression of miR-146a, IL-1 receptor-associated kinase 1 (IRAK1), IL-1β, VEGF and ICAM-1, as well as clock genes was examined by real-time PCR and Western blot. To modulate expression levels of miR-146a, mimics and inhibitors were used. Results Diabetes inhibited amplitude of negative arm (per1) and enhanced amplitude of the positive arm (bmal1) of clock machinery in retina. In addition to clock genes, miR-146a and its target gene IRAK1 also exhibited daily oscillations in antiphase; however, these patterns were lost in diabetic retina. This loss of rhythmic pattern was associated with an increase in ICAM-1, IL-β, and VEGF expression. Human retinal endothelial cells had robust miR-146a expression that followed circadian oscillation pattern; however, HRECs isolated from diabetic donors had reduced miR-146a amplitude but increased amplitude of IRAK1 and ICAM-1. In HRECs, miR-146a mimic or inhibitor caused 1.6- and 1.7-fold decrease or 1.5- and 1.6-fold increase, respectively, in mRNA and protein expression levels of ICAM-1 after 48 hours. Conclusions Diabetes-induced dysregulation of daily rhythms of miR-146a and inflammatory pathways under miR-146a control have potential implications for the development of diabetic retinopathy.
Aircraft Trajectory Optimization and Contrails Avoidance in the Presence of Winds

There are indications that persistent contrails can lead to adverse climate change, although the complete effect on climate forcing is still uncertain. A flight trajectory optimization algorithm with fuel and contrails models, which develops alternative flight paths, provides policy makers the necessary data to make tradeoffs between persistent contrails mitigation and aircraft fuel consumption. This study develops an algorithm that calculates wind-optimal trajectories for cruising aircraft while avoiding the regions of airspace prone to persistent contrails formation. The optimal trajectories are developed by solving a non-linear optimal control problem with path constraints. The regions of airspace favorable to persistent contrails formation are modeled as penalty areas that aircraft should avoid and are adjustable. The tradeoff between persistent contrails formation and additional fuel consumption is investigated, with and without altitude optimization, for 12 city-pairs in the continental United States. Without altitude optimization, the reduction in contrail travel times is gradual with increase in total fuel consumption. When altitude is optimized, a two percent increase in total fuel consumption can reduce the total travel times through contrail regions by more than six times. Allowing further increase in fuel consumption does not seem to result in proportionate decrease in contrail travel times.
Tunneling in quantum field theory with spontaneous symmetry breaking

Abstract Tunneling in quantum field theory is well understood in the case of a single scalar field. However, in theories with spontaneous symmetry breaking, one has to take into account the additional zero modes which appear due to the Goldstone phenomenon. We calculate the false vacuum decay rate in this case. The result may differ significantly from the tunneling rates in the absence of symmetry breaking.
Gate Leakage Suppression and Contact Engineering in Nitride Heterostructures

We present a self-consistent approach to examine current flow in a general metal-polar heterostructure junction. The approach is applied to examine properties of two classes of junctions that are important in devices: (i) GaN/AlGaN/high- κ insulator structures for potential applications in very small gate devices to suppress gate tunneling current; (ii) GaN/AlGaN/LiNbO 3 junctions for both n-type and p-type semiconductors with practical application for low source resistance regions. The physical parameters used for high- κ dielectrics and polarization charges reflect values typically found in ferroelectric materials. Our studies indicate that tailoring of junction properties is possible if polar oxides as thin as ∼ 20A can be achieved.
Excited-state relaxations and Franck-Condon shift in Si quantum dots

Excited-state relaxations in molecules are responsible for a redshift of the absorption peak with respect to the emission peak (Franck-Condon shift). The magnitude of this shift in semiconductor quantum dots is still unknown. Here we report first-principle calculations of excited-state relaxations in small (diameter $l~2.2\mathrm{nm})$ Si nanocrystals, showing that the Franck-Condon shift is surprisingly large $(\ensuremath{\sim}60\mathrm{meV}$ for a 2.2-nm-diameter nanocrystal). The physical mechanism responsible for the Stokes shift changes abruptly around $\ensuremath{\sim}1$ nanometer in size, providing a clear demarcation between ``molecules'' and ``nanocrystals.''
Algorithms for Boolean Function Query Properties

We investigate efficient algorithms for computing Boolean function properties relevant to query complexity. Such properties include, for example, deterministic, randomized, and quantum query complexities; block sensitivity; certificate complexity; and degree as a real polynomial. The algorithms compute the properties, given an n-variable function's truth table (of size N=2n) as input. Our main results are the following: O(N log2 3 log N) algorithms for many common properties, an O(N log2 5 log N) algorithm for block sensitivity, an O(N) algorithm for testing "quasi symmetry," a notion of a "tree decomposition" of a Boolean function, proof that the decomposition is unique, and an O(Nlog2 3 log N) algorithm for finding it, a subexponential-time approximation algorithm for space-bounded quantum query complexity. To develop this algorithm, we give a new way to search systematically through unitary matrices using finite-precision arithmetic. The algorithms discussed have been implemented in a linkable library.
High Spatial Resolution Mid-IR Imaging of V838 Monocerotis: Evidence of New Circumstellar Dust Creation

The eruptive variable V838 Monocerotis experienced three dramatic outbursts in early 2002. Its unexpectedly erratic photometric behavior wes matched by strong spectroscopic variability, in which the srar transitioned through the F, K, G spectral type s in 2002 February, reseabled a M5 supergiant by 2002 Aprll, and had a L-type super qiant spectram in 2002 October. The star is also infamous for producisg e spectacu lar light echo whose evolction has beer traced by HST/ACS. We report high sFatial resolution 11.2 and 18.1 micron imagicq of V838 Nonoceroris obrained with Genini Ob servatory's Klchelle in 2007 March. The 2007 flux density of the unresclved stellar core of is rouqhly 2 tixes brighter than zhaz observed in 2C04. We interpret tkese aata as evidecce t-at V838 Mon has experienced a new circums~ellar dust creatioc evezt. We suggest that this newly c reated dust is Likely clumpy, and speculate that one (or ore) of Ekese clumps migh t have passed through the line-cf-sight in late 2036, prodccing the brief rnalti-wav elength pkotonetric event reported by Bond (2006) and Yunari ez a1 (2007). A gap o f spatially exzended therrrzl (18 micron) emission is present over radial distances of 1860 - 93000 AU from che central source. Assuming ejecta material expands at a constant velocity of 300-500 km/s, this gap suggests that no prior significanz circ unstellar dust production events have occurred withiin the past approx. 900-1500 years.
Uniaxial, shear, and poisson relaxation and their conversion to bulk relaxation: Studies on poly(methyl methacrylate)

Multiple viscoelastic properties were determined for poly(methyl methacrylate) in the context of examining experimental limitations on deriving other properties from these measurements, specifically time dependent bulk modulus behavior. By means of master curves for uniaxial extension on plate and cylinder specimens, as well as shear (torsion) and Poisson behavior from measurements in the temperature range from -40°C to 125°C, it is established that excessive precision is needed for reliable interconversion of some properties to others. While normal inverse relations (modulus-compliance) are readily obtained from one set of measurements, bulk (relaxation or creep) properties cannot be derived reliably from other functions and must be determined directly.