cssi/SciSciGPT-SciSciNet huggingface dataset:
Andreev reflection measurements of spin polarization

We discuss aspects of Andreev reflection (AR) measurements in normal metal-superconductor (N-S) and ferromagnet-superconductor (F-S) devices. We describe the analytical model used to quantify spin polarization from the conductance measurements and discuss the validity of this simple model using parabolic bands as simple surrogates for real band structures. We present (AR) measurements of spin polarization in a $\mathrm{Cu}\text{\ensuremath{-}}\mathrm{Pt}\text{\ensuremath{-}}\mathrm{Pb}$ and $\mathrm{Co}\text{\ensuremath{-}}\mathrm{Pt}\text{\ensuremath{-}}\mathrm{Pb}$ lithographically fabricated nanocontact systems where a scattering layer of has been deliberately added to the interface to enable the study of the effect of pair-breaking scattering on AR conductance and spin polarization. We compare these results to the previously published results from clean $\mathrm{Cu}\text{\ensuremath{-}}\mathrm{Pb}$ and $\mathrm{Co}\text{\ensuremath{-}}\mathrm{Pb}$ devices and argue that the measurements in devices with the Pt layer can be explained by the presence of inelastic-scattering-induced pair-breaking effects. We modify the analytical model to include this effect and show that in some instances, it may be impossible to distinguish between the effects of a finite spin polarization and inelastic scattering. This has implications for AR measurements of spin polarization at disordered or poorly formed F-S interfaces.
Bayesian Inference in Trust Networks

Trust has emerged as a major impediment to the success of electronic markets and communities where interaction with the strangers is the norm. Social Networks and Online Communities enable interaction with complete strangers, and open up new commercial, political, and social possibilities. But those promises are rarely achieved because it is difficult to trust the online contacts. A common approach to remedy this problem is to compute trust values for the new contacts from the existing trust values in the network. There are two main methods: aggregation and transitivity. Yet, neither method provides satisfactory results because trust networks are sparse and transitivity may not hold. This article develops a Bayesian formulation of the problem, where trust is defined as a conditional probability, and a Bayesian Network analysis is employed to compute the unknown trust values in terms of the known trust values. The algorithms used to propagate conditional probabilities through the network are theoretically sound and based on a long-standing literature on probability propagation in Bayesian networks. Moreover, the context information that is typically ignored in trust literature is included here as a major factor in computing new trust values. These changes have led to significant improvements over existing approaches in the accuracy of computed trust, and with some modifications to the algorithm, in its reach. Real data acquired from Advogato network is used to do extensive testing, and the results confirm the practical value of a theoretically sound Bayesian approach.
In Pursuit of Balance: Randomization in Practice in Development Field Experiments

Randomized experiments are increasingly used in development economics, with researchers now facing the question of not just whether to randomize, but how to do so. Pure random assignment guarantees that the treatment and control groups will have identical characteristics on average, but in any particular random allocation, the two groups will differ along some dimensions. Methods used to pursue greater balance include stratification, pair-wise matching, and re-randomization. This paper presents new evidence on the randomization methods used in existing randomized experiments, and carries out simulations in order to provide guidance for researchers. Three main results emerge. First, many researchers are not controlling for the method of randomization in their analysis. The authors show this leads to tests with incorrect size, and can result in lower power than if a pure random draw was used. Second, they find that in samples of 300 or more, the different randomization methods perform similarly in terms of achieving balance on many future outcomes of interest. However, for very persistent outcome variables and in smaller sample sizes, pair-wise matching and stratification perform best. Third, the analysis suggests that on balance the re-randomization methods common in practice are less desirable than other methods, such as matching.
Lagrangian with off-shell vertices and field redefinitions

Meson exchange diagrams following from a lagrangian with off-shell meson-nucleon couplings are compared with those generated from conventional dynamics. The off-shell interactions can be transformed away with the help of a nucleon field redefinition. Contributions to the NN- and 3N-potentials and nonminimal contact e.m. meson-exchange currents are discussed, mostly for an important case of scalar meson exchange.
Diffusion in LanCoIn3n+2 Phases Studied by Perturbed Angular Correlation

Jump frequencies of 111In/Cd tracer atoms were measured for a series of layered phases LanCoIn3n+2 using the technique of perturbed angular correlation of gamma rays (PAC). The frequencies were determined by analysis of nuclear quadrupole relaxation produced by fluctuating electric field gradients. Samples were synthesized having nominal values n= 1, 2, 3, 5 and , with n= corresponding to the L12 phase LaIn3. The phases form heuristically from LaIn3 by replacing every (n+1)th (100) mixed plane of La and In atoms with a plane of Co-atoms. For the n=1 phase, LaCoIn5, jump frequencies were too small to detect. Two signals were observed, one for indium atoms next to the Co-planes and the other for more distant indium atoms. No relaxation was observed for atoms next to the Co-planes, indicating that there is no diffusion across the Co-planes. With increasing n, jump rates for the other In-atoms increased toward values observed for LaIn3. Jump frequency activation enthalpies for n= 3 and 5 were observed to be the same as for n=, suggesting the same diffusion mechanism. However, the jump-frequency prefactors were found to be smaller for small n, which is attributed to reductions in the connectivity of the diffusion sublattice. We conclude that diffusion in the layered phases is remarkably similar to diffusion in LaIn3 once the reduced connectivity is taken into account.
Liquidity Provision with Limit Orders and a Strategic Specialist

This article presents a microstructure model of liquidity provision in which a specialist with market power competes against a competitive limit order book. General solutions, comparative statics and examples are provided first with uninformative orders and then when order flows are informative. The model is also used to address two optimal market design issues. The first is the effect of "tick" size--for example, eighths versus decimal pricing--on market liquidity. Institutions trading large blocks have a larger optimal tick size than small retail investors, but both prefer a tick size strictly greater than zero. Second, a hybrid specialist/limit order market (like the NYSE) provides better liquidity to small retail and institutional trades, but a pure limit order market (like the Paris Bourse) may offer better liquidity on mid-size orders. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Vector transform and image coding

A vector transform is introduced. The application of the vector transform to image coding is discussed. The development of a vector transform coding technique consists of two parts. One part is to find a vector transform that has the decorrelation and energy-packing properties. The other part is to find a coding algorithm in the vector transform domain. A vector transform, originally developed for digital filtering, is used. It is shown that this vector transform does have the decorrelation and energy-packing properties. Codebook design algorithms for the transform domain vectors are discussed. An implementation scheme for the vector transform is presented. >
CONSISTENCY VIA TYPE 2 INEQUALITIES: A GENERALIZATION OF WU'S THEOREM

Wu introduced a new technique for proving consistency of least-squares estimators in nonlinear regression. This paper extends his results in three directions. First, we consider the minimization of arbitrary functions (M-estimators instead of least squares). Second, we use an improved type 2 inequality. Third, an extension of Kronecker's lemma yields a more powerful result.
Two-graviton interaction in pp-wave background in Matrix theory and Supergravity

Abstract We compute the two-body one-loop effective action for the Matrix theory in the pp-wave background, and compare it to the effective action on the Supergravity side in the same background. Agreement is found for the effective actions on both sides. This points to the existence of a supersymmetric nonrenormalization theorem in the pp-wave background.
Oxidation of magnesium single crystals and evaporated films

Abstract The oxidation of (001) and (100) faces of pure magnesium single crystals at 2.5 mm Hg oxygen pressure was measured at 400°C and 440°C by means of an all-quartz, high vacuum microbalance. In a first approximation a parabolic oxidation law is observed. The oxidation rate on the basal plane is initially higher than on the prismatic plane. Electron diffraction patterns and photomicrographs indicate that the oxide has a preferred orientation on the basal plane, even for a thickness of about 1000 A. The oxidation of evaporated magnesium films at room temperature was also investigated. After an induction period a logarithmic oxidation law is observed, where the limiting thickness is dependent on the oxygen pressure.
MAGNETICALLY REGULATED GAS ACCRETION IN HIGH-REDSHIFT GALACTIC DISKS

Disk galaxies are in hydrostatic equilibrium along their vertical axis. The pressure allowing for this configuration consists of thermal, turbulent, magnetic, and cosmic-ray components. For the Milky Way the thermal pressure contributes ~10% of the total pressure near the plane, with this fraction dropping toward higher altitudes. Out of the rest, magnetic fields contribute ~1/3 of the pressure to distances of ~3 kpc above the disk plane. In this Letter, we attempt to extrapolate these local values to high-redshift, rapidly accreting, rapidly star-forming disk galaxies and study the effect of the extra pressure sources on the accretion of gas onto the galaxies. In particular, magnetic field tension may convert a smooth cold-flow accretion to clumpy, irregular star formation regions and rates. The infalling gas accumulates on the edge of the magnetic fields, supported by magnetic tension. When the mass of the infalling gas exceeds some threshold mass, its gravitational force cannot be balanced by magnetic tension anymore, and it falls toward the disk's plane, rapidly making stars. Simplified estimations of this threshold mass are consistent with clumpy star formation observed in SINS, UDF, GOODS, and GEMS surveys. We discuss the shortcomings of pure hydrodynamic codes in simulating the accretion of cold flows into galaxies, and emphasize the need for magnetohydrodynamic simulations.
The space of embedded minimal surfaces of fixed genus in a 3-manifold III; Planar domains

This paper is the third in a series where we describe the space of all embedded minimal surfaces of fixed genus in a fixed (but arbitrary) closed 3-manifold. In [CM3]–[CM5] we describe the case where the surfaces are topologically disks on any fixed small scale. Although the focus of this paper, general planar domains, is more in line with [CM6], we will prove a result here (namely, Corollary III.3.5 below) which is needed in [CM5] even for the case of disks. Roughly speaking, there are two main themes in this paper. The first is that stability leads to improved curvature estimates. This allows us to find large graphical regions. These graphical regions lead to two possibilities:
An unequivocal synthesis of the ring-A,B dihydropyrromethenone of phytochrome

Abstract Dihydropyrromethenone 1b (R = p -methoxybenzyl), a potential precursor for the synthesis of phytochrome ( 3 ), has been prepared in enantiomerically pure form beginning with the homochiral acetylenic lactone 18 .
Common Mathematical Foundations of Expected Utility and Dual Utility Theories

We show that the main results of the expected utility and dual utility theories can be derived in a unified way from two fundamental mathematical ideas: the separation principle of convex analysis, and integral representations of continuous linear functionals from functional analysis. Our analysis reveals the dual character of utility functions. We also derive new integral representations of dual utility models.
Supercritical fluid chromatography-mass spectrometry: A potentially useful technique for porphyrin analysis

Abstract Supercritical fluid chromatography-mass spectrometry (SFC-MS) and related analytical techniques offer the potential of making significant contributions to the analysis and characterization of geoporphyrins in complex matrices. The combination of a chromatographic separation method with mass spectrometric detection provides a powerful tool as evidenced by the dominance of gas chromatography-mass spectrometry (GC-MS) for the characterization of amenable compounds. The favorable physical properties and high solvating powers of supercritical fluids allow separation of less-volatile and higher-molecular-weight compounds generally restricted to liquid chromatography with separation efficiency per unit time and chromatographic resolution approaching that of gas chromatography. Furthermore, mild operating temperatures (determined by the choice of mobile phase) allow application to thermally labile compounds that cannot generally be addressed by GC. The potential advantages of SFC-MS for porphyrin analysis and the results from preliminary porphyrin analyses are described in this paper.
Intersection local times for interlacements

Abstract We define renormalized intersection local times for random interlacements of Levy processes in R d and prove an isomorphism theorem relating renormalized intersection local times with associated Wick polynomials.
Transient analysis of volatile organic compound concentrations for estimating emission rates

Abstract While emission rates of volatile organic compounds (VOCs) have been obtained for building materials, furnishings and processes in chambers, field measurements are more difficult. Procedures to estimate emission rates using transient analysis of VOC concentrations are described and applied in a two-story classroom/office building. The analysis employs semi-real-time VOC concentrations determined with a portable GC/FID and simultaneous air change rate measurements using tracer gas decay. The results of the analysis yield consistent values of emission rates for building materials ranging from 0.20 to 0.40 mg m −2 h −1 when normalized by floor area. Occupancy-related emissions were more difficult to estimate and covered a wider range from roughly 0.1 to 1.5 mg m −2 h −1 . The test data were also analyzed in an attempt to determine sink parameters, but these efforts were not particularly successful. Furthermore, in these tests, the inclusion of sink effects did not significantly impact the estimated emission rates. While this paper offers a transient analysis approach that may lead to improved field estimates of VOC emission rates, it is not presented as a definitive methodology. Nevertheless, transient analysis has potential for use in other buildings, but simultaneous air change rate measurements are critical in its application in estimating VOC emission rates in the field.
Lyapunov redesign of analog phase-lock loops

The second method of Lyapunov is proposed as a method for analyzing the stability and tracking of the nonlinear phase-lock loop model. It is shown that a fairly regular procedure, known as Lyapunov design, which is quite well known in the area nonlinear control theory, is applicable to solving this class of problems. The ability of loops designed using these techniques to track a phase step is also proven. >
The role of energy in real business cycle models

Abstract This paper modifies Hansen's (1985) analysis of a real business cycle mode] with indivisible labor by explicitly including energy as a productive input and modelling the relative price of energy as an exogenous random process. One goal is to determine the extent to which the introduction of energy price shocks reduces the reliance of the real business cycle model on unobserved technology shocks. The other goal, following Christiano and Eichenbaum (1991), is to compare the correlation between real wages and hours predicted by the energy-inclusive model to that predicted by Hansen's model.
Statistical mechanics of adiabatic processes

Abstract The thermodynamic equivalence of an Ehrenfest adiabatic process and an isentropic process is investigated by examining the difference between the susceptibilities calculated under isentropic and Ehrenfest adiabatic conditions. It is found that except under quite restrictive conditions this difference does not vanish. However, it is usually too small to be of thermodynamic significance. The necessary conditions that these processes be thermodynamically equivalent are that the system be able to maintain thermal equilibrium during the process and that the fluctuations of the energy in the canonical ensemble be small.
A novel cardioport for beating-heart, image-guided intracardiac surgery

Objective Intracardiac beating-heart procedures require the introduction and exchange of complex instruments and devices. To prevent potential complications such as air embolism and bleeding, a universal cardioport was designed and tested. Methods The design consists of a port body and a series of interchangeable sleeves. The port uses a fluid purging system to remove air from the instrument before insertion into the heart, and a valve system minimizes blood loss during instrument changes. Results The cardioport was tested ex vivo and in vivo in pigs (n = 5). Beating-heart procedures, such as septal defect closure and mitral valve repair, were modeled. Ex vivo trials (n = 150) were performed, and no air emboli were introduced using the port. In comparison, air emboli were detected in 40% to 85% of the cases without the use of the port-based purging system. Port operation revealed excellent ergonomics and minimal blood loss. Conclusions A novel cardioport system designed to prevent air entry and blood loss from transcardiac instrument introduction was shown to be an enabling platform for intracardiac beating-heart surgery. The port system improves safety and facilitates further development of complex instruments and devices for transcardiac beating-heart surgery.
Characteristics of the earth radiation budget experiment solar monitors.

The earth radiation budget experiment solar monitors, active cavity pyrheliometers, have been developed to measure every two weeks the total optical solar irradiance from the earth radiation budget satellite (ERBS) and the National Oceanic and Atmospheric Administration NOAA-9 spacecraft platforms. In the unfiltered 0.2-50-micron wavelength broadband region, the monitors were used to obtain 1365 W/sq m as the mean value for the solar irradiance, with measurement precisions and accuracies approaching 0.1 and 0.2 percent, respectively. The design and characteristics of the solar monitors are presented along with the data reduction model. For the October 1984 through July 1985 period, the resulting ERBS and NOAA-9 solar irradiance values are intercompared.
X-ray observations of the North Polar Spur

The X-ray enhancement associated with the North Polar Spur (Radio Loop I) was observed by a soft X-ray instrument on OSO 8 during August 1975. This paper presents image-processed maps of the region scanned, a detailed analysis of the X-ray data, and interpretations of the data in terms of supernova remnant models. If the neutral hydrogen ridge, radio continuum ridge, and X-ray emission ridge are all associated, then they cannot all be fitted by a single supernova remnant model because they require different energies of explosion. A reheated supernova remnant model does appear compatible with all the available observations.
Space-based orbital transfer vehicle

Abstract The objectives of the Orbital Transfer Vehicle (OTV) Concept Definition and Systems Analysis study, conducted by General Dynamics Space Systems Division under company funds with data provided to NASA-MSFC, were to define the requirements, concepts, and evolutionary approaches for development of an OTV for reusable operations to GEO and beyond, including manned access; assess the requirements of space basing; and define the interaction between the OTV and Space Station. The study focused primarily on answering fundamental OTV questions: whether the OTV should be reusable or expendable; ground-based or space-based; cryogenic or storable; delivered in the STS cargo bay or the ACC; single-stage, two-stage, or with modular tanks; aeroassisted or all-propulsive; and whether it should use a new advanced engine or an RL-10 derivative. Major effort centered on concept generation, evaluation, and selection; operations and Space Station accommodations; system analysis and evaluation; and program definition. Study findings show that mission requirements and substantial economic benefits justify a reusable, cryogenic H 2 O 2 ), space-based OTV. The success of the Space Shuttle has demonstrated the effectiveness of reusable launch vehicles to Low Earth Orbit. With reusability extended to OTVs and with the coming of the Space Station, a new era in orbital transfer operations will offer lower cost for payload users and open the way for manned exploration of the solar system.
Approximating the smallest k-edge connected spanning subgraph by LP-rounding

The smallest k-ECSS problem is, given a graph along with an integer k, find a spanning subgraph that is k-edge connected and contains the fewest possible number of edges. We examine a natural approximation algorithm based on rounding an LP solution. A tight bound on the approximation ratio is 1 + 3-k for undirected graphs with k > 1 odd, 1 + 2-k for undirected graphs with k even, and 1 + 2-k for directed graphs with k arbitrary. Using iterated rounding improves the first upper bound to 1 + 2-k. On the hardness side we show that for some absolute constant c > 0, for any integer k ≥ 2 (k ≥ 1), a polynomial-time algorithm approximating the smallest k-ECSS on undirected (directed) multigraphs to within ratio 1 + c-k would imply P = NP. © 2008 Wiley Periodicals, Inc. NETWORKS, 2009
Dynamics of a Compact Operator

Let 𝑇∶𝑋→𝑋 be a compact linear (or more generally affine) operator from a Banach space into itself. For each 𝑥∈𝑋, the sequence of iterates 𝑇𝑛𝑥, 𝑛=0, 1, … and its averages ∑(1/𝑘)𝑛𝑘=0𝑇𝑘−1𝑥,𝑛=0, 1, … are either bounded or approach infinity.
Supermassive Black Hole Binaries as Galactic Blenders

This paper focuses on the dynamical implications of close supermassive black hole binaries both as an example of resonant phase mixing and as a potential explanation of inversions and other anomalous features observed in the luminosity profiles of some elliptical galaxies. The presence of a binary comprised of black holes executing nearly periodic orbits leads to the possibility of a broad resonant coupling between the black holes and various stars in the galaxy. This can result in efficient chaotic phase mixing and, in many cases, systematic increases in the energies of stars and their consequent transport toward larger radii. Allowing for a supermassive black hole binary with plausible parameter values near the center of a spherical, or nearly spherical, galaxy characterized initially by a Nuker density profile enables one to reproduce in considerable detail the central surface brightness distributions of such galaxies as NGC 3706.
APPLICATION OF SUPPORT VECTOR MACHINES TO GLOBAL PREDICTION OF NUCLEAR PROPERTIES

Advances in statistical learning theory present the opportunity to develop statistical models of quantum many-body systems exhibiting remarkable predictive power. The potential of such "theory-thin" approaches is illustrated with the application of Support Vector Machines (SVMs) to global prediction of nuclear properties as functions of proton and neutron numbers Z and N across the nuclidic chart. Based on the principle of structural-risk minimization, SVMs learn from examples in the existing database of a given property Y, automatically and optimally identify a set of "support vectors" corresponding to representative nuclei in the training set, and approximate the mapping (Z, N) → Y in terms of these nuclei. Results are reported for nuclear masses, beta-decay lifetimes, and spins/parities of nuclear ground states. These results indicate that SVM models can match or even surpass the predictive performance of the best conventional "theory-thick" global models based on nuclear phenomenology.
Experiments on N − P Scattering with 260-Mev Neutrons

Neutrons produced by 350 Mev protons impinging on beryllium are scattered by hydrogen. We measure the differential scattering cross section as a function of the scattering angle. Results are summarized in Fig. 3 of the paper.
From Columbia to Discovery: Understanding the impact threat to the space shuttle

Abstract The loss of the space shuttle Columbia in 2003 was caused by the impact of foam insulation on the leading edge of the wing. The foam strike created a hole in reinforced carbon–carbon panel 8 that led to excessive heating during re-entry, loss of the integrity of the left wing, and subsequent loss of the vehicle and crew. In the 2.5 years following the accident, there was a concerted effort to understand the impact threat to the space shuttle system. The effort was a large one, and was comprised of five integrated parts: (1) identifying the debris that can be shed by the External Tank and Solid Rocket Boosters; (2) determining the impact speeds and angles that debris can strike the Orbiter; (3) quantifying the amount of damage to the thermal protection system caused by those strikes; (4) estimating the temperature rise in the damaged regions during re-entry; and (5) deciding whether the temperature rise is sufficient to affect structural integrity. Each of these parts was addressed through experimentation and the development of what are called within the space shuttle program Critical Math Models. These models are extensively verified and validated to give high confidence in their results and are baselined by the shuttle program. This paper overviews the extensive experimental and modeling efforts of the return-to-flight program, emphasizing the impact testing and modeling.
Crystal Shapes and Phase Equilibria: A Common Mathematical Basis

Geometrical constructions, such as the tangent construction on the molar free energy for determining whether a particular composition of a solution is stable, are related to similar tangent constructions on the orientation-dependent interfacial energy for determining stable interface orientations and on the orientation dependence of the crystal growth rate which tests whether a particular orientation appears on a growing crystal. Subtle differences in the geometric constructions for the three fields arise from the choice of a metric (unit of measure). Using results from studies of extensive and convex functions, we demonstrate that there is a common mathematical structure for these three disparate topics and use this to find new uses for well-known graphical methods for all three topics. Thus, the use of chemical potentials for solution thermodynamics is very similar to known vector formulations for surface thermodynamics and the method of characteristics which tracks the interfaces of growing crystals; the Gibbs-Duhem equation is analogous to the Cahn-Hoffman equation. The Wulff construction for equilibrium crystal shapes can be modified to construct a “phase shape” from solution free energies that is a potentially useful method of numerical calculations of phase diagrams from known thermodynamical data.
Gauge-Mediated Supersymmetry Breaking : Introduction, Review and Update

Abstract Recent progress inthhe gauge-mediated supersymmetry breaking is reviewed, with emphasis on the theoretical problems which gauge-mediated models are so successful at solving, as well as the problems which are endemic to the models themselves and still beguile theorists today.
Joint Characteristic Function of Stock Log-Price and Squared Volatility in the Bates Model and Its Asset Pricing Applications

The model of Bates specifies a rich, flexible structure of stock dynamics suitable for applications in finance and economics, including valuation of derivative securities. This paper analytically derives a closed-form expression for the joint conditional characteristic function of a stock’s log-price and squared volatility under the model dynamics. The use of the function, based on inverting it, is illustrated on examples of pricing European-, Bermudan-, and American-style options. The discussed approach for European-style derivatives improves on the option formula of Bates. The suggested approach for American-style derivatives, based on a compound-option technique, offers an alternative solution to existing finite-difference methods.
Race and the Construction of Evidence in Homicide Cases

Research that attempts to document racial or gender disparities in the criminal justice system inevitably paints a distorted picture if only one point in the criminal justice process is examined. For example, studies that look at who is sentenced to death among a group convicted of first-degree murder will miss exposure of biases that occur at earlier stages of the criminal justice process. In this paper, we looked at prosecutorial files on over 400 homicide cases from Caddo Parish, Louisiana (the Shreveport area). Results indicate that even after controlling for aggravating factors, cases with White female victims result in thicker files than other homicides, indicating more prosecutorial effort in attempting to secure convictions in such cases. This, in turn, was related to more severe sentencing of offenders convicted of killing whites and women. On the other hand, cases with black victims resulted in the thinnest case files and the least severe sentences.
Effect of Treatment of Diabetic Rats with Dehydroepiandrosterone on Vascular and Neural Function

Nutritional supplementation with dehydroepiandrosterone (DHEA) may be a candidate for treating diabetes-induced vascular and neural dysfunction. DHEA is a naturally occurring adrenal androgen that has antioxidant properties and is reportedly reduced in diabetes. Using a prevention protocol, we found that dietary supplementation of streptozotocin-induced diabetic rats with 0.1, 0.25, or 0.5% DHEA caused a concentration-dependent prevention in the development of motor nerve conduction velocity and endoneurial blood flow impairment, which are decreased in diabetes. At 0.25%, DHEA significantly prevented the diabetes-induced increase in serum thiobarbituric acid-reactive substances and sciatic nerve conjugated diene levels. This treatment also reduced the production of superoxide by epineurial arterioles of the sciatic nerve. DHEA treatment (0.25%) significantly improved vascular relaxation mediated by acetylcholine in epineurial vessels of diabetic rats. Sciatic nerve Na+−K+−ATPase activity and myoinositol content was also improved by DHEA treatment, whereas sorbitol and fructose content remained elevated. These studies suggest that DHEA, by preventing oxidative stress and perhaps improving sciatic nerve Na+−K+−ATPase activity, may improve vascular and neural dysfunction in diabetes.
Passive control of flow-induced vibrations by splitter blades

Splitter blades as a passive control technique for flow-induced vibrations are investigated by developing an unsteady aerodynamic model to predict the effect of incorporating splitter blades into the design of an axial flow blade row operating in an incompressible flow field. The splitter blades, positioned circumferentially in the flow passage between two principal blades, introduce aerodynamic and/or combined aerodynamic-structural detuning into the rotor. The unsteady aerodynamic gust response and resulting oscillating cascade unsteady aerodynamics, including steady loading effects, are determined by developed a complete first-order unsteady aerodynamic analysis together with an unsteady aerodynamic influence coefficient technique. The torsion mode flow induced vibrational response of both uniformly spaced tuned rotors and detuned rotors are then predicted by incorporating the unsteady aerodynamic influence coefficients into a single-degree-of-freedom aeroelastic model. This model is then utilized to demonstrate that incorporating splitters into axial flow rotor designs is beneficial with regard to flow induced vibrations.
A Polarimetric Search for Hidden Quasars in Three Radio-selected Ultraluminous Infrared Galaxies

We have carried out a spectropolarimetric search for hidden broad-line quasars in three ultraluminous infrared galaxies (ULIRGs) discovered in the positional correlations between sources detected in deep radio surveys and the IRAS Faint Source Catalog. Only the high-ionization Seyfert 2 galaxy TF J1736+1122 is highly polarized, displaying a broad-line spectrum visible in polarized light. The other two objects, TF J1020+6436 and FF J1614+3234, display spectra dominated by a population of young (A type) stars similar to those of E+A galaxies. They are unpolarized, showing no sign of hidden broad-line regions. The presence of young starburst components in all three galaxies indicates that the ULIRG phenomenon encompasses both active galactic nuclei (AGNs) and starburst activity, but the most energetic ULIRGs do not necessarily harbor buried quasars. We find that a luminous infrared galaxy is most likely to host an obscured quasar if it exhibits a high-ionization ([O III] λ5007/Hβ 5) spectrum typical of a classic Seyfert 2 galaxy with little or no Balmer absorption lines, is ultraluminous (LIR1012 L☉), and has a warm IR color (f25/f600.25). The detection of hidden quasars in this group but not in the low-ionization, starburst-dominated ULIRGs (classified as LINERs or H II galaxies) may indicate an evolutionary connection, with the latter being found in younger systems.
A Cost Comparison of Nephron-Sparing Surgical Techniques for Renal Tumour

Objective: To compare costs associated with open partial nephrectomy (OPN), laparoscopic PN (LPN) and percutaneous radiofrequency ablation (PRF) in consecutive patients undergoing nephron-sparing surgery. Patients and Methods: The charts and costs were reviewed for all 46 patients undergoing nephron-sparing PN at our institution from March 2003 to March 2004. Clinical characteristics, operative techniques, radiographic and pathological information were recorded. Detailed cost information for room and board, laboratory, pharmacy, radiology, operating room, surgical supplies, anaesthesia, recovery room, electrocardiography and respiratory services were obtained from our institution. Results: The hospital stay was significantly shorter for PRF (0.5 days) than either LPN (1.86) and OPN (4.94). PRF was statistically less costly than LPN and OPN, with mean (SD) costs of (US$) 4454 (938) 7013(934) and 7767 (1605). There was no significant difference in cost between LPN and OPN. Surgical supply costs were significantly higher for LPN and PRF than OPN. LPN had less than a third of the room and board costs of OPN (P 0.001). Decreases in room and board were also associated with lower pharmacy and laboratory costs. Conclusions: PRF is significantly less costly than LPN and OPN; LPN is cost-equivalent to OPN as the shorter stay compensates for significantly higher surgical supply costs. In those patients with tumours of appropriate size and location, minimally invasive approaches can decrease the morbidity, with cost benefits.
Recent developments in D = 2 string field theory

We review the recent developments in the construction of string field theory in two dimensions. We analyze the bewildering number of string field theories that have been proposed, all of which correctly reproduce the correlation functions of two-dimensional string theory. These include (1) free fermion field theory, (2) collective string field theory, (3) temporal gauge string field theory and (4) nonpolynomial string field theory. We will analyze discrete states, the ω(∞) symmetry, and correlation functions in terms of these different string field theories. We will also comment on the relationship between these field theories, which is still not well understood.
The Variance of Two Game Tree Algorithms

This article studies the variance of two game tree algorithms, ?-s search and SCOUT, in the stochastic i.i.d. model. The problem of determining the variance of the classic ?-s search algorithm in the i.i.d. model was long open. This article resolves this problem partially. It is shown, by the martingale method, that the standard deviation of the weaker ?-s search without deep cutoffs is of the same order as the expected number of leaves evaluated. A nearly optimal upper bound on the variance of the general ?-s search is obtained. A thorough treatment of the two-pass SCOUT algorithm is presented. The variance of the SCOUT algorithm is determined.
SOLAR FAST-WIND REGIONS AS SOURCES OF SHOCK ENERGETIC PARTICLE PRODUCTION

If the production of solar energetic particles (SEPs) near the Sun is due to shocks driven by coronal mass ejections (CMEs), then two factors might favor SEP acceleration in slow rather than fast solar wind streams. The first is that both the MHD fast-mode and solar wind flow speeds are higher in the fast-wind streams. The second is that shock seed populations in the fast-wind streams consist of weak suprathermal ion tails with soft spectra. An earlier study used observed fast west-limb or halo CMEs and solar wind O+7/O+6 ratios to compare associated SEP events and fast CMEs in fast wind with those in slow wind. Properties of the few fast CMEs in fast-wind regions suggested a bias in terms of associated SEP event size and/or CME speed against shock production of SEPs in fast-wind regions. Here the previous 1998-2000 study is expanded through 2002. The results of the much larger event sample now show no significant bias against SEP production in fast-wind regions. We discuss the implications of this result for shock seed populations and for shock propagation in coronal fast-wind regions.
Feature Screening for Ultrahigh Dimensional Categorical Data With Applications

Ultrahigh dimensional data with both categorical responses and categorical covariates are frequently encountered in the analysis of big data, for which feature screening has become an indispensable statistical tool. We propose a Pearson chi-square based feature screening procedure for categorical response with ultrahigh dimensional categorical covariates. The proposed procedure can be directly applied for detection of important interaction effects. We further show that the proposed procedure possesses screening consistency property in the terminology of Fan and Lv (2008). We investigate the finite sample performance of the proposed procedure by Monte Carlo simulation studies and illustrate the proposed method by two empirical datasets.
NICMOS Imaging of Infrared-Luminous Galaxies

We present near-infrared images obtained with the Hubble Space Telescope NICMOS camera for a sample of nine luminous [LIGs: LIR(8?1000 ?m) ? 1011 L?] and 15 ultraluminous (ULIGS: LIR ? 1012 L?) infrared galaxies. The sample includes representative systems classified as warm (f25 ?m/f60 ?m > 0.2) and cold (f25 ?m/f60 ?m ? 0.2) based on the mid-infrared colors and systems with nuclear emission lines classified as H II (i.e., starburst), QSO, Seyfert, and LINER. The morphologies of the sample galaxies are diverse and provide further support for the idea that they are created by the collision or interactions of spiral galaxies. Although no new nuclei are seen in the NICMOS images, the NICMOS images do reveal new spiral structures, bridges, and circumnuclear star clusters. The colors and the luminosities of the observed clusters are consistent with them being young (107?108 yr), formed as a result of galactic interactions, and having masses much greater than those of Galactic globular clusters. In NGC 6090 and VV 114, they are preferentially situated along the area of overlap of the two galactic disks. With the exception of IR 17208-0018, all of the ULIGs have at least one compact (2.2??m FWHM ? 200 pc) nucleus. Analysis of the near-infrared colors (i.e., m1.1?1.6 vs. m1.6?2.2) derived from 11 diameter apertures suggests that the warm galaxies have near-infrared colors consistent with QSO+hot dust emission and the cold galaxies, as a group, have near-infrared colors consistent with reddened starlight. In addition, the cold ULIG UGC 5101 (and possibly three others) have near-infrared colors suggesting additional active galactic nucleus?like near-infrared components in their nuclei. In a 2 kpc diameter aperture measurement, the global colors of all of the cold galaxies except UGC 5101 are consistent with starlight with a few magnitudes of visual extinction. The general dichotomy of the near-infrared properties of the warm and the cold galaxies are further supported by the light distributions: seven of the eight warm galaxies have unresolved nuclear emission that contributes significantly (i.e., ?30%?40%) to the total near-infrared luminosity. The smooth, more extended light observed in all of the galaxies is most likely composed of giant and supergiant stars, but evidence at longer wavelengths suggests that these stars contribute little to the high 8?1000 ?m luminosity of these galaxies. Finally, light profiles of nine of the 24 systems were fitted well by an r1/4 law (and not so well by an exponential disk profile). Whether these star systems eventually become massive central bulges or giant elliptical galaxies will depend on how efficiently the present ISM is converted into stars.
Antibiotic-Associated Diarrhea

A 53-year-old woman reports severe watery diarrhea with cramps. She is in her 7th day of a 10-day course of cefixime, prescribed for bronchitis. How should she be evaluated and treated?
Energy dissipating hybrid control for impulsive dynamical systems

Abstract A novel class of fixed-order, energy-based hybrid controllers is proposed as a means for achieving enhanced energy dissipation in nonsmooth Euler–Lagrange, hybrid port-controlled Hamiltonian, and lossless impulsive dynamical systems. These dynamic controllers combine a logical switching architecture with hybrid dynamics to guarantee that the system plant energy is strictly decreasing across switchings. The general framework leads to hybrid closed-loop systems described by impulsive differential equations. Special cases of energy-based hybrid controllers involving state-dependent switching are described, and an illustrative numerical example is given to demonstrate the efficacy of the proposed approach.
Tight Bounds for Averaging Multi-Frequency Differential Inclusions, Applied to Control Systems

We present new tight bounds for averaging differential inclusions, which we apply to multi-frequency inclusions consisting of a sum of time periodic set-valued mappings. For this family of inclusions we establish a tight estimate of order O (𝜖) on the approximation error. These results are then applied to control systems consisting of a sum of time-periodic functions.
Multi-atoms and Monotonicity of Generalized Kostka Polynomials

There is a certain family of Poincare polynomials that arise naturally in geometry. They satisfy a monotonicity property and admit a combinatorial description in terms of a graded poset whose elements are called Littlewood?Richardson tableaux. The purpose of this article is to give a combinatorial explanation of the monotonicity by exhibiting embeddings of these graded posets. In particular, these posets embed into the cyclage poset of Lascoux and Schutzenberger, which was introduced to explain the monotonicity of the Kostka?Foulkes polynomials. The image of the embedding into the cyclage poset is characterized, giving another combinatorial description of the Poincare polynomials in terms of the catabolizable tableaux defined by the author and J. Weyman.
Antitumor agents. Part 209: Pheophorbide-a derivatives as photo-Independent cytotoxic agents

Abstract A methanolic crude extract of the plant Garuga pinnata Roxb. (Burseraceae) showed promising cytotoxic activity against a panel of human tumor cell lines in vitro, including KB and its drug-resistant sublines (Ferguson et al. Cancer Res. 1988, 48 , 5956). Pheophorbide- a and- b methyl esters ( 3 , 4 ) were isolated as active principles with broad photo-dependent cytotoxic activities in the micromolar range. These findings prompted SAR studies of known and novel pheophorbide- a derivatives as photo-dependent and photo-independent cytotoxic agents. The results showed that zinc-protoporphyrin IX ( 10 ), zinc 13 2 ( R )-hydroxypheophorbide- a methyl ester ( 22 ), and zinc chlorin- e 6 trimethyl ester ( 13 ) possessed photo-independent cytotoxic activity. Compounds 13 and 22 were the most active cytotoxic agents of the series (mean ED 50 4.6±1.0 μM and 5.7±0.7 μM, respectively) against KB cells incubated in the dark.
Choosing the Number of Instruments

Properties of instrumental variable estimators are sensitive to the choice of valid instruments, even in large cross-section applications. In this paper we address this problem by deriving simple mean-square error criteria that can be minimized to choose the instrument set. We develop these criteria for two-stage least squares (2SLS), limited information maximum likelihood (LIML), and a bias adjusted version of 2SLS (B2SLS). We give a theoretical derivation of the mean-square error and show optimality. In Monte Carlo experiments we find that the instrument choice generally yields an improvement in performance. Also, in the Angrist and Krueger (1991) returns to education application, when the instrument set is chosen in the way we consider, it turns out that both 2SLS and LIML give similar (large) returns to education.
Parallel sphere rendering

Sphere rendering is an important method for visualizing molecular dynamics data. This paper presents a parallel algorithm that is almost 90 times faster than current graphics workstations. To render extremely large data sets and large images, the algorithm uses the MIMD features of the supercomputers to divide up the data, render independent partial images, and then finally composite the multiple partial images using an optimal method. The algorithm and performance results are presented for the CM-5 and the T3D.
The impact of SFAS No. 141 on earnings predictability of merging firms: Evidence from the initial year of implementation

Abstract This study examines the impact of SFAS 141 on earnings predictability of merging firms. I expect a relative improvement in analysts’ earnings forecast accuracy for merging firms versus non-merging peers after SFAS 141 adoption. I restrict the post-SFAS 141 sample to the initial year of SFAS 141 implementation. This research design disentangles effects of SFAS No. 141 from those of SFAS No. 142. The evidence from analysis of 48 pairs of merging and matched non-merging firms is consistent with expectations and confirms the increase in earnings predictability for merging firms versus their non-merging peers post-SFAS 141. Results of additional tests suggest that earnings predictability improvement more likely follows from extended disclosure requirements and the other changes in the Purchase Method (“better purchase” issue) than from the elimination of Poolings-of-Interest (“purchase vs. pooling” issue).