cssi/SciSciGPT-SciSciNet huggingface dataset:
Development of test facility and optical instrumentation for turbulent combustion research

Practical combustion systems as complex as a gas turbine combustor, a ramjet, or an afterburner pose many design and modeling difficulties. This has created an urgent need for well conceived turbulent combustion experiments to validate the models and to improve their potential design capabilities. With that broad goal in mind, the U.S. Air Force Wright Aeronautical Laboratories, Aero Propulsion Laboratory initiated a major program with the University of Dayton Research Institute to 1) develop a sophisticated combustion test facility, 2) develop state-of-the-art optical instrumentation capable of measurements in nonreactiye and reactive turbulent flows, and 3) carry out well conceived turbulent combustion experiments. This paper describes the development of the combustion test facility and the optical instrumentation. A turbulent flame burner provides low exit turbulence (<0.25%), predictable velocity profile; and it is capable of producing a variety of flame configurations. A two-component LDA system, capable of measuring velocity fluctuations over three orders of magnitude, has been designed. A three-channel laser Raman/Rayleigh spectroscopy (LRS) system, which can simultaneously measure temperature, density, and species concentration, has been constructed. Integration pf the LDA-LRS systems is carried out to measure complex correlations between velocity, temperature, concentration, and density in a turbulent flame. Design and development of auxiliary systems and equipment such as fuel and airflow networks, LDA seeders, and the flow visualization system are described in detail.
The continuous spectrum of the Orr-Sommerfeld equation. Part 1. The spectrum and the eigenfunctions

It is shown that the Orr-Sommerfeld equation, which governs the stability of any mean shear flow in an unbounded domain which approaches a constant velocity in the far field, has a continuous spectrum. This result applies to both the temporal and the spatial stability problem. Formulae for the location of this continuum in the complex wave-speed plane are given. The temporal continuum eigenfunctions are calculated for two sample problems: the Blasius boundary layer and the two-dimensional laminar jet. The nature of the eigenfunctions, which are very different from the Tollmien-Schlichting waves, is discussed. Three mechanisms are proposed by which these continuum modes could cause transition in a shear flow while bypassing the usual linear Tollmien-Schlichting stage.
Married and cohabiting parents' relationship stability: A focus on race and ethnicity.

We draw on three waves of the Fragile Families Study (N =2,249) to examine family stability among a recent birth cohort of children. We find that children born to cohabiting versus married parents have over five times the risk of experiencing their parents’ separation. This difference in union stability is greatest for White children, as compared with Black or Mexican American children. For White children, differences in parents’ education levels, paternal substance abuse, and prior marriage and children account for the higher instability faced by those born to cohabiting parents, whereas differences in union stability are not fully explained among Black and Mexican American children. These findings have implications for policies aimed at promoting family stability and reducing inequality.
Risk dominance and coordination failures in static games

Abstract This article presents: (1) arguments comparing the use of Harsanyi and Selten's risk dominance (a measure of the ‘risk’ associated with choosing an action which supports an equilibrium) and payoff dominance as equilibrium selection criteria; (2) new experimental evidence which suggests the existence of a payoff dominated risk dominant equilibrium is a necessary (but not sufficient) condition for coordination failure and the existence of a tradeoff between risk dominance and payoff dominance; and (3) new experimental evidence which links risk dominance and payoff dominance to the speed of convergence to equilibrium.
TERMINAL CHALCOGENIDO COMPLEXES OF GROUP 13 AND 14 ELEMENTS

Abstract The syntheses, structures and reactivity of multiply bonded terminal chalcogenido complexes of the Group 13 and 14 elements is reviewed. In particular, specific attention is given to complexes that can be generated under ambient conditions and retain the terminal chalcogenido moiety in the solid state.
An Analysis of Default Correlations and Multiple Defaults

Evaluating default correlations or the probabilities of default by more than one firm is an important task in credit analysis, derivatives pricing, and risk management. However, default correlations cannot be measured directly, multiple-default modeling is technically difficult, and most existing credit models cannot be applied to analyze multiple defaults. This article develops a first-passage-time model, providing an analytical formula for calculating default correlations that is easily implemented and conveniently used for a variety of financial applications. The model also provides a theoretical justification for several empirical regularities in the credit risk literature. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
Waveguide integrated low noise NbTiN nanowire single-photon detectors with milli-Hz dark count rate

Superconducting nanowire single-photon detectors are an ideal match for integrated quantum photonic circuits due to their high detection efficiency for telecom wavelength photons. Quantum optical technology also requires single-photon detection with low dark count rate and high timing accuracy. Here we present very low noise superconducting nanowire single-photon detectors based on NbTiN thin films patterned directly on top of Si3N4 waveguides. We systematically investigate a large variety of detector designs and characterize their detection noise performance. Milli-Hz dark count rates are demonstrated over the entire operating range of the nanowire detectors which also feature low timing jitter. The ultra-low dark count rate, in combination with the high detection efficiency inherent to our travelling wave detector geometry, gives rise to a measured noise equivalent power at the 10−20 W/Hz1/2 level.
Computed tomographic anatomy of the temporal bone

With the recent development of high-resolution computed tomography (CT), there is a growing need to explore the full potential of this new method in demonstrating the detailed anatomy of the temporal bone. For this purpose, dry skulls with intact ossicles were scanned in axial and coronal projections. The detailed CT anatomy of the temporal bone was documented, complemented by images from live patients. Because of its superior contrast resolution, CT was able to demonstrate numerous structures, such as the tympanic membrane, ossicles, and supporting structures, hitherto never or poorly visualized by any other method. In addition, the ease by which axial sections of the temporal bone could be obtained is of great benefit in displaying several structures previously difficult to evaluate.
Folding versus self-assembling

Model foldable polymers with sequences of rigid hydrophobic chromophores and flexible hydrophilic tetra(ethylene glycol) were synthesized and used as a paradigm for studying molecular-folding and self-assembly phenomena. Our results demonstrate that intramolecular association or folding prevails over intermolecular interaction or self-assembling in the concentration region from 1 microM to 0.1 M. Importantly, folded polymeric nanostructures have absorption and fluorescence properties that are distinct from those of unfolded polymers or free monomers. We hypothesize that the origins of folding and self-assembly come from interactions between molecular units, and that the key parameter that regulates the on-and-off of such interactions is the distance R separating the two molecular units. Each molecular unit produces a characteristic force field, and when another molecular unit enters this field, the probability that the two units will interact increases significantly. A preliminary estimate of the radius of such a force field for the perylene tetracarboxylic diimide chromophore is about 90-120 A. As a result, phenomena associated with folding or self-assembly of molecular species are observed when these conditions are met in solution.
Is revenue sharing right for your supply chain

Many firms have enjoyed remarkable success using revenue-sharing contracts to improve supply chain performance. The video rental industry and its pioneering deal with movie studios is one such example. At the same time, other firms have struggled to make it work. What accounts for this difference? When can revenue sharing create significant value and what are the implementation costs? By comparing and contrasting several case examples, this article develops a general framework that helps answer these questions, which is based on the fundamental sources of added value and added costs.
An agency theory of unionism

Abstract An agency theory of unionism is developed to explain the diversity of union accomplishments by the diversity of principals, the diversity of costs of providing union benefits, and the potential for agent malfeasance. The theory produces a number of testable hypotheses, including: larger plants will unionize before smaller plants; the scope of union representation will grow as members go from untrained to specifically trained to generally trained; employers will pay for union representation of unskilled employees, but not for others; and the slope of earnings with respect to seniority will be flatter in union firms than in non-union firms
The Galactic Center Magnetosphere

The magnetic field within a few hundred parsecs of the center of the Galaxy is an essential component of any description of that region. The field has several pronounced observational manifestations: 1) morphological structures such as nonthermal radio filaments (NTFs) - magnetic flux tubes illuminated by synchrotron emission from relativistic electrons - and a remarkable, large-scale, helically wound structure, 2) relatively strong polarization of thermal dust emission from molecular clouds, presumably resulting from magnetic alignment of the rotating dust grains, and 3) synchrotron emission from cosmic rays. Because most of the NTFs are roughly perpendicular to the Galactic plane, the implied large-scale geometry of the magnetic field is dipolar. Estimates of the mean field strength vary from tens of microgauss to ~ a milligauss. The merits and weaknesses of the various estimations are discussed here. If the field strength is comparable to a milligauss, then the magnetic field is able to exert a strong infiience on the dynamics of molecular clouds, on the collimation of a Galactic wind, and on the lifetimes and bulk motions of relativistic particles. Related to the question of field strength is the question of whether the field is pervasive throughout the central zone of the Galaxy, or whether its manifestations are predominantly localized phenomena. Current evidence favors the pervasive model.
Synthesis and Anticancer Activity of 5-(Propargyloxymethyl)-2-oxazolidinones

Abstract: To determine the feasibility of producing a tissue-specific anticancer agent, a series of 2-oxazolidinones bearing an alkynoxymethyl side chain in the 5-position was prepared. These compounds were submitted to the National Cancer Institute for testing against L-1210 and/or P-388 tumor test systems. None of the compounds showed significant anticancer activity. The synthetic procedures and NMR spectral properties of the title compounds are described.
Architecture, design, and development of an HTML/JavaScript web-based group support system

This article describes the need for virtual workspaces and then discusses the architecture, design, and development of GroupSystems for the World Wide Web (Web) (GSWeb), an HTML/JavaScript Web-based Group Support System (GSS). To design and develop GSWeb, a user-driven approach was employed which drew on feedback from users and teams working with a GSWeb prototype, interviews with GSS users and facilitators, and over 10 years of experience with face-to-face group support research, development, and design. GSWeb was built using HTML 3.0 and JavaScript for client interface rendering. The result is an application interface that is like the familiar Graphical User Interface (GUI) interfaces that are today a defacto standard. GSWeb is currently being used by teams from all over the world, and continuing design and development still relies on feedback and requests from actual users to refine and extend the features that will enable virtual teams to be productive and accomplish real work. © 1998 John Wiley & Sons, Inc.
Mechanism of Material Removal from Silicon Carbide by Carbon Dioxide Laser Heating

The mechanism of material removal from SiC by CO2 laser heating was studied using sintered and single-crystal α-SiC. Removal rate and width of the groove showed maxima when plotted as a function of translation speeds. Groove depth decreased as the translation speed of samples increased. Similar results were obtained if argon or air was used as gas assist, which indicated that the material removal mechanism is induced dissociation of SiC. Microstructure of the material deposited in and outside of the groove was studied by SEM. At low scanning speeds, columnar grains 10 to 50 μm long appeared. As the scanning speed increased, columnar grains became smaller and finally only irregular polycrystalline particles were observed. By using Raman spectroscopy, Auger analysis, and X-ray diffraction, phases inside and outside the groove were identified as Si, β-SiC, C, and SiO2. Columnar grains were identified as β-SiC covered with thin layers of C, Si, and SiO2. Slow scanning speeds enhanced the growth of β-SiC. At slow scanning speed, free silicon was always found in the grooves of lased single crystals but not in the grooves of lased sintered SiC. It can be concluded that the mechanism of material removal from silicon carbide by CO2 laser heating is a vaporization process, and material found in the groove and on the surface near the groove is formed by condensation from the vapor.
Regularity of area-minimizing surfaces in 3D polytopes and of invariant hypersurfaces in R n

In (the surface of) a convex polytope P 3 inR 4,an areaminimizing surface avoids the vertices of P and crosses the edges orthogonally. In a smooth Riemannian manifold M with a group of isometries G, an areaminimizing G-invariant oriented hypersurface is smooth (except for a very small singular set in high dimensions). Already in 3D, area-minimizing G-invariant unoriented surfaces can have certain singularities, such as three orthogonal sheets meeting at a point. We also treat other categories of surfaces such as rectifiable currents modulo v and soap films.
Transonic drag prediction on a DLR-F6 transport configuration using unstructured grid solvers

Abstract A second international AIAA Drag Prediction Workshop (DPW-II) was organized and held in Orlando Florida on June 21–22, 2003. The primary purpose was to investigate the code-to-code uncertainty, address the sensitivity of the drag prediction to grid size and quantify the uncertainty in predicting nacelle/pylon drag increments at a transonic cruise condition. This paper presents an in-depth analysis of the DPW-II computational results from three state-of-the-art unstructured grid Navier-Stokes flow solvers exercised on similar families of tetrahedral grids. The flow solvers are USM3D – a tetrahedral cell-centered upwind solver, FUN3D – a tetrahedral node-centered upwind solver, and NSU3D – a general element node-centered central-differenced solver. Overall, grid refinement did not consistently improve the correlation with experimental data for either the wing/body or the wing/body/nacelle pylon configuration. Although, the range in total drag for the wing/body fine grids was only 5 counts, a code-to-code comparison of surface pressures and surface restricted streamlines indicated that the three solvers were not all converging to the same flow solutions– different shock locations and separation patterns were evident. Similarly, the wing/body/nacelle/pylon solutions did not appear to be converging to the same flow solutions. Although the absolute values of total drag predicted by two of the solvers for the medium and fine grids did not compare well with the experiment, the incremental drag predictions were within ±3 counts of the experimental data. Although, the sources of code-to-code variation in force and moment predictions for the three unstructured grid codes have not yet been identified, the current study reinforces the necessity of applying multiple codes to the same application to assess uncertainty.
An analytical model for thermal stress analysis of multi-layered microelectronic packaging

Compared to numerical methods, analytical solutions can offer a faster and more accurate procedure for obtaining the interfacial stresses in laminated structures. An analytical model for thermal stress analysis of multi-layered thin stacks on a thick substrate under isothermal loading is proposed in this paper. This analytical approach considers each layer as a beam-type plate with orthotropic material properties. Highly sensitive Moire interferometry is used to validate the model. The strain field in the bi-material interfaces is obtained experimentally. The test data is in good agreement with the proposed analytical solution. Finite element analysis results are also compared with the analytical solution and the test data.
Ratio vectors of fourth degree polynomials

Abstract Let p ( x ) be a polynomial of degree 4 with four distinct real roots r 1 r 2 r 3 r 4 . Let x 1 x 2 x 3 be the critical points of p, and define the ratios σ k = x k − r k r k + 1 − r k , k = 1 , 2 , 3 . For notational convenience, let σ 1 = u , σ 2 = v , and σ 3 = w . ( u , v , w ) is called the ratio vector of p. We prove necessary and sufficient conditions for ( u , v , w ) to be a ratio vector of a polynomial of degree 4 with all real roots. Most of the necessary conditions were proven in an earlier paper. The main results of this paper involve using the theory of Groebner bases to prove that those conditions are also sufficient.
Reduction of Ordering Effect in Reliability-Based Design Optimization Using Dimension Reduction Method

In reliability-based design optimization problems with correlated input variables, a joint cumulative distribution function needs to be used to transform the correlated input variables into independent standard Gaussian variables for the inverse reliability analysis. To obtain a true joint cumulative distribution function, a very large number of data (if not infinite) needs to be used, which is impractical in industry applications. In this paper, a copula is proposed to model the joint cumulative distribution function using marginal cumulative distribution functions and correlation parameters obtained from samples. Using the joint cumulative distribution function modeled by the copula, the transformation and the first-order reliability method can be carried out. However, the first-order reliability method may yield different reliability analysis results for different transformation ordering of input variables. Thus, the most probable-point-based dimension reduction method, which is more accurate than the first-order reliability method and more efficient than the second-order reliability method, is proposed for the inverse reliability analysis to reduce the effect of transformation ordering.
Speed estimation and length based vehicle classification from freeway single-loop detectors

Roadway usage, particularly by large vehicles, is one of the fundamental factors determining the lifespan of highway infrastructure. Operating agencies typically employ expensive classification stations to monitor large vehicle usage. Meanwhile, single-loop detectors are the most common vehicle detector and many new, out-of-pavement detectors seek to replace loop detectors by emulating the operation of single-loop detectors. In either case, collecting reliable length data from these detectors has been considered impossible due to the noisy speed estimates provided by conventional data aggregation at single-loop detectors. This research refines non-conventional techniques for estimating speed at single-loop detectors, yielding estimates that approach the accuracy of a dual-loop detector's measurements. Employing these speed estimation advances, this research brings length based vehicle classification to single-loop detectors (and by extension, many of the emerging out-of-pavement detectors). The classification methodology is evaluated against concurrent measurements from video and dual-loop detectors. To capture higher truck volumes than empirically observed, a process of generating synthetic detector actuations is developed. By extending vehicle classification to single-loop detectors, this work leverages the existing investment deployed in single-loop detector count stations and real-time traffic management stations. The work also offers a viable treatment in the event that one of the loops in a dual-loop detector classification station fails and thus, also promises to improve the reliability of existing classification stations.
The pebbling threshold of the square of cliques

Given an initial configuration of pebbles on a graph, one can move pebbles in pairs along edges, at the cost of one of the pebbles moved, with the objective of reaching a specified target vertex. The pebbling number of a graph is the minimum number of pebbles so that every configuration of that many pebbles can reach any chosen target. The pebbling threshold of a sequence of graphs is roughly the number of pebbles so that almost every (resp. almost no) configuration of asymptotically more (resp. fewer) pebbles can reach any chosen target. In this paper we find the pebbling threshold of the sequence of squares of cliques, improving upon an earlier result of Boyle and verifying an important instance of a probabilistic version of Graham's product conjecture.
Against a proposed alternative explanation of the Aharonov-Bohm effect.

The Aharonov-Bohm (AB) effect is understood to demonstrate that the Maxwell fields can act nonlocally in some situations. However it has been suggested from time to time that the AB effect is somehow a consequence of a local classical electromagnetic field phenomenon involving energy that is temporarily stored in the overlap between the external field and the field of which the beam particle is the source. That idea was shown in the past not to work for some models of the source of the external field. Here a more general proof is presented for the magnetic AB effect to show that the overlap energy is always compensated by another contribution to the energy of the magnetic field in such a way that the sum of the two is independent of the external flux. Therefore no such mechanism can underlie the AB effect.
Improved total synthesis of the potent HDAC inhibitor FK228 (FR-901228).

A scaleable synthesis of the potent histone deacetylase (HDAC) inhibitor FK228 is described. A reliable strategy for preparing the key β-hydroxy mercapto heptenoic acid partner was accomplished in nine steps and 13% overall yield. A Noyori asymmetric hydrogen-transfer reaction established the hydroxyl stereochemistry in >99:1 er via the reduction of a propargylic ketone.
Tracing Compressed Curves in Triangulated Surfaces

A simple path or cycle in a triangulated surface is normal if it intersects any triangle in a finite set of arcs, each crossing from one edge of the triangle to another. A normal curve is a finite set of disjoint normal paths and normal cycles. We describe an algorithm to “trace” a normal curve in $$O(\min \{ X, n^2\log X \})$$ time, where $$n$$ is the complexity of the surface triangulation and $$X$$ is the number of times the curve crosses edges of the triangulation. In particular, our algorithm runs in polynomial time even when the number of crossings is exponential in $$n$$ . Our tracing algorithm computes a new cellular decomposition of the surface with complexity $$O(n)$$ ; the traced curve appears in the 1-skeleton of the new decomposition as a set of simple disjoint paths and cycles. We apply our abstract tracing strategy to two different classes of normal curves: abstract curves represented by normal coordinates, which record the number of intersections with each edge of the surface triangulation, and simple geodesics, represented by a starting point and direction in the local coordinate system of some triangle. Our normal-coordinate algorithms are competitive with and conceptually simpler than earlier algorithms by Schaefer et al. (Proceedings of 8th International Conference Computing and Combinatorics. Lecture Notes in Computer Science, vol. 2387, pp. 370–380. Springer, Berlin 2002; Proceedings of 20th Canadian Conference on Computational Geometry, pp. 111–114, 2008) and by Agol et al. (Trans Am Math Soc 358(9): 3821–3850, 2006).
Palladium-catalyzed synthesis of cis-2-[4-(9H-Purin-9-yl)-2-cyclopenten-1-yl]ethanol analogues

A concise 6–7 step synthesis of the carbocyclic nucleosides cis-2-[4-(9H-Purin-9-yl)-2-cyclopenten-1-yl]ethanol analogues utilizing palladium chemistry has been described.
A Mössbauer study of ferromagnetic domain orientation in amorphous Fe75P15C10 foils

Abstract Mossbauer studies of splat cooled amorphous Fe75P15C10 foils show that in “as prepared” samples, the magnetization is essentially in the plane of the foil. However, by annealing at 600 K for 1 h, the magnetization becomes predominantly perpendicular to the surface (85%). Thus, splat cooled materials may support the fomation of bubble domains.
Thiourea-catalyzed aminolysis of N-acyl homoserine lactones.

Thiourea catalysts accelerate aminolysis of N-acyl homoserine lactones (AHLs), molecules integral to bacterial quorum sensing. The catalysts afford rate enhancement of up to 10 times the control in CD3CN. Mild catalysis in other polar aprotic solvents is still observed, while the activity is attenuated in polar protic solvents.
1, 2-Asymmetric cis induction and its application to the asymmetric synthesis of precursors of β-branched unusual amino acids

Abstract A new method for the asymmetric synthesis of key intermediates of unusual amino acids has been established by utilizing β-carbon chirality for asymmetric induction in allylic-strained boron enolates.
Experiences with Binary Periodic Signals for Dynamic Testing at the HFIR

The power-to-reactivity frequency response of the High-Flux Isotope Reactor (HFIR) was measured over the range 0.01 to 5 Hz using periodic binary input signals introduced with normal system control rods. These results served to validate the theoretical model used in the HFIR control and safety studies and to aid in assessing this testing procedure for use in large power reactors where special test equipment or interference with normal operation cannot be tolerated.
SrRietveld: a program for automating Rietveld refinements for high-throughput powder diffraction studies

SrRietveld is a highly automated software toolkit for Rietveld refinement. Compared to traditional refinement programs, it is more efficient to use and easier to learn. It is designed for modern high-throughput diffractometers and is capable of processing large numbers of data sets with minimal effort. The software currently uses conventional Rietveld refinement engines, automating GSAS and FullProf refinements. However, as well as automating and extending many tasks associated with these programs, it is designed in a flexible and extensible way so that in the future these engines can be replaced with new refinement engines as they become available. SrRietveld is an open-source software package developed in Python.
Multiplicative Attribute Graph Model of Real-World Networks

Large scale real-world network data such as social and information networks are ubiquitous. The study of such networks seeks to find patterns and explain their emergence through tractable models. In most networks, and especially in social networks, nodes have a rich set of attributes associated with them. We present the Multiplicative Attribute Graphs (MAG) model, which naturally captures the interactions between the network structure and the node attributes. We consider a model where each node has a vector of categorical latent attributes associated with it. The probability of an edge between a pair of nodes depends on the product of individual attribute-attribute similarities. The model yields itself to mathematical analysis. We derive thresholds for the connectivity and the emergence of the giant connected component, and show that the model gives rise to networks with a constant diameter. We also show that MAG model can produce networks with either log-normal or power-law degree distributions.
Accountability Myopia: Losing Sight of Organizational Learning:

This article challenges a normative assumption about accountability in organizations: that more accountability is necessarily better. More specifically, it examines two forms of “myopia” that chara...
How Haptic Size Sensations Improve Distance Perception

Determining distances to objects is one of the most ubiquitous perceptual tasks in everyday life. Nevertheless, it is challenging because the information from a single image confounds object size and distance. Though our brains frequently judge distances accurately, the underlying computations employed by the brain are not well understood. Our work illuminates these computions by formulating a family of probabilistic models that encompass a variety of distinct hypotheses about distance and size perception. We compare these models' predictions to a set of human distance judgments in an interception experiment and use Bayesian analysis tools to quantitatively select the best hypothesis on the basis of its explanatory power and robustness over experimental data. The central question is: whether, and how, human distance perception incorporates size cues to improve accuracy. Our conclusions are: 1) humans incorporate haptic object size sensations for distance perception, 2) the incorporation of haptic sensations is suboptimal given their reliability, 3) humans use environmentally accurate size and distance priors, 4) distance judgments are produced by perceptual “posterior sampling”. In addition, we compared our model's estimated sensory and motor noise parameters with previously reported measurements in the perceptual literature and found good correspondence between them. Taken together, these results represent a major step forward in establishing the computational underpinnings of human distance perception and the role of size information.
Physician Organization In California: Crisis And Opportunity

Many of the 250 physician organizations that provide care to California’s sixteen million health maintenance organization enrollees are in a state of crisis, squeezed between constrained revenues, rising practice costs, and consumer sentiment that favors unconstrained choice over integrated delivery. Medical groups and independent practice associations are retrenching to their core geographic areas, reducing capitation for drug benefits and hospital services, and abandoning dreams of displacing health plans. Consolidation is accelerating in some areas, as medical groups join with hospitals to extract higher payment rates from insurers and employers. The conjunction of consumerism and premium inflation creates new opportunities for organizations that truly can manage health care, but the challenges roiling California’s medical groups may preclude meaningful efforts to seize the initiative.
Going-concern initial public offerings

Abstract We study the relation between audit reports and the capital-raising activities of small business by studying the role of going-concern (GC) audit opinions in IPOs. After controlling for other effects, we find that the presence of a GC opinion is positively related to whether a stock delists (for deleterious reasons) within two years of IPO. We also find that GC IPOs suffer less first-day underpricing. Based on Rock (1986), this implies that firms with GCs have less ex ante uncertainty in the sense that the information conveyed by a GC helps uninformed investors estimate the dispersion of secondary market values.
SUSY Simplified Models at 14, 33, and 100 TeV Proton Colliders

Results are presented for a variety of SUSY Simplified Models at the 14 TeV LHC as well as a 33 and 100 TeV proton collider. Our focus is on models whose signals are driven by colored production. We present projections of the upper limit and discovery reach in the gluino-neutralino (for both light and heavy flavor decays), squark-neutralino, and gluino-squark Simplified Model planes. Depending on the model a jets + $ E_T^{\mathrm{miss}} $ , mono-jet, or same-sign di-lepton search is applied. The impact of pileup is explored. This study utilizes the Snowmass backgrounds and combined detector. Assuming 3000 fb−1 of integrated luminosity, a gluino that decays to light flavor quarks can be discovered below 2.3 TeV at the 14 TeV LHC and below 11 TeV at a 100 TeV machine.
Recent developments in the computational aspects of MHD stability

Abstract In recent years variational methods have been applied successfully to the numerical determination of the spectra for simple linearized ideal magnetohydrodynamic models. Currently, several extensive efforts have been undertaken to implement these approaches to determine the normal modes for general axisymmetric toroidal equilibria, especially those applicable to the Tokamak experimental program. This paper reviews the motivation, the difficulties, and the various numerical approaches employed. Several simple illustrative results are given.
Phenomenological theory of superfluidity and superconductivity

Quantum condensation is used here as the basis for a phenomenological theory of superfluidity and superconductivity. It leads to remarkably good calculations of the transition temperaturesT c of superfluid3He and4He, as well as a large number of cuprate, heavy fermion, organic, dichalcogenide, and bismuth oxide superconductors. Although this approach may apply least to the long-coherence-length metallics, reasonably good estimates are made for them and chevral superconductors.T c for atomic H is estimated.T c can be calculated as a function of number density or density of states and effective mass of normal carriers; or alternatively with the Fermi energy as the only input parameter. Predictions are made for a total of 26 superconductors and four superfluids. An estimate is also made for coherence lengths.
Adaptive coordinate, real-space electronic structure calculations on parallel computers☆

Abstract We present a method for electronic structure calculations that retains all of the advantages of real space, but addresses the major weakness of a regular grid, i.e., its inability to treat some regions of space with more resolution than others. The computations are carried out on a regular mesh in curvilinear space, which allows natural and efficient decomposition on parallel computers, and effective use of iterative numerical methods. A novel feature is the use of error analysis to optimize the curvilinear grid for highly inhomogeneous electronic distributions. We report accurate all-electron calculations for H2, O, and O2.
The Lack of Halo Ultraluminous X-Ray Sources

The premise that ultraluminous X-ray sources (ULXs) exist beyond the optical extent of nearby galaxies is investigated. A published catalog containing 41 ULX candidates located between 1 and ~3 times the standard D25 isophotal radius of their putative host galaxies is examined. Of these sources, 21 have spectroscopically confirmed distances. All 21 are background objects, giving a 95% probability that at least 37 of the 41 candidates are background sources. In addition, 39 of the 41 sources have X-ray-to-optical flux ratios in the range -1.6 < log(FX/FO) < +1.3, consistent with those of background active galactic nuclei. [The remaining two are not detected in the optical to a weak limit of mB ~ 21.5 mag, corresponding to log(FX/FO) 1.6.] The uniform spatial distribution of the sample is also consistent with a background population. This evidence suggests that ULXs rarely, if at all, exist beyond the distribution of luminous matter in nearby galaxies and, as a consequence, there is no correlation between the population of ULXs and halo objects, such as old globular clusters or Population III remnants.
The 2-(allyloxy) phenyl acetyl ester as a new relay protecting group for oligosaccharide synthesis

Abstract The 2-(allyloxy) phenyl acetyl group can be removed by a relay approach using Pd(PPh 3 ) 4 in combination with proton sponge, conditions that do not affect acetyl, benzoyl and levulinoyl esters. On the other hand, the acetyl and levulinoyl ester could be cleaved without removal of the 2-(allyloxy) phenyl acetyl group. The new protecting group is compatible with glycosylations and can perform efficiently neighboring group participation leading to the exclusive formation of 1,2- trans glycosides.
Initial Margin Requirements, Volatility, and the Individual Investor: Insights from Japan

Initial margin requirements represent: (1) a cost impediment to the wealth constrained investor and (2) a potential way of mitigating excessive volatility. However, prior empirical research finds that margins are not an effective tool in reducing volatility. We consider the possibility that margins primarily affect certain stocks and investors. Specifically, we test whether margins affect individuals who, as a group, we believe to be the investors most affected when margin requirements change. Our initial empirical tests, however, do not support this contention.
Molten Salt Synthesis of a Complex Perovskite, Pb(Fe0.5Nb0.5)O3

Pure, single-phase stoichiometric Pb(Fe0.5Nb0.5)O3 (PFN) powders were successfully formed by molten salt synthesis using mixtures of NaCl and KCl salts. Lower temperatures and shorter times (1/2 h at 800°C) were needed for singlephase PFN formation from molten salts relative to those required for solid-phase methods (4 h at 1000°C). A systematic study indicating the effects of process parameters, such as temperature, time, and amount of flux with respect to starting oxides, on the PFN formation mechanism and its resulting powder characteristics is reported. The particle size increased with increasing synthesis temperature; the rate of increase was greatest above 900°C, which is close to the melting point of PbO. PFN powders formed by molten salt synthesis are spheroidal, free from aggregates, and sintered to good densities at temperatures as low as 1000°C.
The Development of the First Catalyzed Reaction of Ketenes and Imines: Catalytic, Asymmetric Synthesis of β-Lactams

We report practical methodology for the catalytic, asymmetric synthesis of β-lactams resulting from the development of a catalyzed reaction of ketenes (or their derived zwitterionic enolates) and imines. The products of these asymmetric reactions can serve as precursors to a number of enzyme inhibitors and drug candidates as well as valuable synthetic intermediates. We present a detailed study of the mechanism of the β-lactam forming reaction with proton sponge as the stoichiometric base, including kinetics and isotopic labeling studies. Stereochemical models based on molecular mechanics (MM) calculations are also presented to account for the observed stereoregular sense of induction in our reactions and to provide a guidepost for the design of other catalyst systems.
The Ice-Water Test in the Diagnosis and Treatment of the Neurogenic Bladder

Objective To determine the usefulness of the ice-water test (IWT) in the diagnosis and treatment of neurological bladder disease. Patients and methods The IWT was carried out in 148 patients with neuropathic bladder dysfunction resulting from a traumatic lesion, to assist in their diagnosis and treatment, and in 130 patients with neuropathic bladder dysfunction and multiple pathogenic disorders; the results of the IWT were used to classify those patients with hyperactive bladders. Results The IWT was positive in 95% of patients affected by complete and in 86% of patients with incomplete medullary lesions. The IWT in patients with lower motor neuron medullary lesions was always negative. The test was used diagnostically in all patients with lower and in 43% of those with upper motor neuron lesions. In the latter, it was used in 48% of patients as a rehabilitation method during the medullary-shock phase to accelerate the appearance of the micturition reflex. In 9% of patients it was used to induce micturition during cystography. Conclusion Because it is simple to perform, the IWT is a useful complement to urodynamic examinations in patients with neurological bladder disease and in patients with micturitional disorders that are otherwise difficult to interpret.
Natural curvature for manifest T-duality

We reformulate the manifestly T-dual description of the massless sector of the closed bosonic string, directly from the geometry associated with the (left and right) affine Lie algebra of the coset space Poincare/Lorentz. This construction initially doubles not only the (spacetime) coordinates for translations but also those for Lorentz transformations (and their “dual”). As a result, the Lorentz connection couples directly to the string (as does the vielbein), rather than being introduced ad hoc to the covariant derivative as previously. This not only reproduces the old definition of T-dual torsion, but automatically gives a general, covariant definition of T-dual curvature (but still with some undetermined connections).
Common asset pricing factors in volatilities and returns in futures markets

Abstract Factor-based asset pricing models have been used to explain the common predictable variation in excess asset returns. This paper combines means with volatilities of returns in several futures markets to explain their common predictable variation. Using a latent variables methodology, tests do not reject a single factor model with a common time-varying factor loading. The single common factor accounts for up to 53% of the predictable variation in the volatilities and up to 14% of the predictable variation in the means. S&P500 futures volatility predicted by the factor model is highly correlated with volatility implied in S&P500 futures options. But both the factor and implied volatilities are significant in predicting future volatility. In derivatives pricing, both implied volatility from options and factors extracted from asset pricing models should be employed.
The first voyage around the world: From Pigafetta to García Márquez

(1985). The first voyage around the world: From Pigafetta to Garcia Marquez. History of European Ideas: Vol. 6, No. 4, pp. 385-404.
Vertical oxide etching without inducing change in critical dimensions

In order to reactive ion etch (in a commercially available hex system) a feature in silicon dioxide leaving a vertical sidewall profile with no change in the resultant linewidth relative to the photoresist mask, it was found necessary to utilize a bilevel masking structure with polysilicon acting as the nonerodable hard mask. This hard mask prevents tapering and linewidth changes due to lateral photoresist erosion during the oxide etch. In addition, the etch was performed under conditions producing very little fluorocarbon polymer deposition to prevent lateral mask growth during the etch, and at very low pressure (≈5 mTorr) to reduce off-angle ion scatter-induced etching due to collisions in the plasma sheath. In a nonpolymer-depositing mode, the lack of sidewall passivation was found to promote lateral etching of the oxide at pressures where this scattering occurs. The same phenomena were found to be present when etching nonphotomasked oxide sidewall spacers. Etching spacers in a very nonpolymerizing chemistry at normal operating pressures (≈50 mTorr) caused significant lateral erosion of the spacers. Use of a low pressure, nonpolymerizing chemistry, or a higher pressure, polymerizing process gave spacer widths consistent with the deposited thickness of the spacer material.
Non-strange chaotic attractors equivalent to their templates

We construct systems of three autonomous first-order differential equations with bounded two-dimensional attracting sets M. The semi-flows on M are chaotic and have one-dimensional Poincare sections whose Poincare maps project to chaotic maps of the interval. The attractors are two-dimensional rather than fractal, and when ‘unzipped’ they are topologically equivalent to the templates of suspended horseshoes.
Impact of acamprosate on plasma amyloid-β precursor protein in youth: a pilot analysis in fragile X syndrome-associated and idiopathic autism spectrum disorder suggests a pharmacodynamic protein marker.

Background Understanding of the pathophysiology of autism spectrum disorder (ASD) remains limited. Brain overgrowth has been hypothesized to be associated with the development of ASD. A derivative of amyloid-β precursor protein (APP), secreted APPα (sAPPα), has neuroproliferative effects and has been shown to be elevated in the plasma of persons with ASD compared to control subjects. Reduction in sAPPα holds promise as a novel molecular target of treatment in ASD. Research into the neurochemistry of ASD has repeatedly implicated excessive glutamatergic and deficient GABAergic neurotransmission in the disorder. With this in mind, acamprosate, a novel modulator of glutamate and GABA function, has been studied in ASD. No data is available on the impact of glutamate or GABA modulation on sAPPα function.
EVIDENCE ON THE EXISTENCE OF COMMON STOCK INFLATION HEDGES

Previous researchers have been unable to identify (on an ex ante basis) inflation hedge portfolios consisting of common stocks. This study demonstrates a procedure for forming common stock portfolios that offer returns that vary positively with unexpected inflation. The strategy could have been used to hedge against purchasing power risk during the 1974-1979 period. In addition to its practical value, the research has important implications for capital asset pricing theory since the existence of hedge portfolios is a necessary condition for the superiority of the multi-period CAPM over the single-period models.
A trace inequality with a subtracted term

Abstract For fixed real or complex matrices A and B , the well-known von Neumann trace inequality identifies the maximum of |tr( UAVB )z.sfnc;, as U and V range over the unitary group, the maximum being a bilinear expression in the singular values of A and B . This paper establishes the analogue of this inequality for real matrices A and B when U and V range over the proper (real) orthogonal group. The maximum is again a bilinear expression in the singular values, but there is a subtracted term when A and B have determinants of opposite sign.
Free and very free morphisms into a Fermat hypersurface

This paper studies the existence of free and very free curves on the degree 5 Fermat hypersurface in P^5 over a field of characteristic 2. We find that such curves exist in degrees 8 and 9 and not in lower degrees.
Persistent exciton-type many-body interactions in GaAs quantum wells measured using two-dimensional optical spectroscopy

Studies have shown that many-body interactions among semiconductor excitons can produce distinct features in two-dimensional optical spectra. However, to the best of our knowledge, the dynamics of many-body interactions have not been measured in two-dimensional (2D) spectroscopy studies. Here we measure 2D spectra of GaAs quantum wells at many different ``waiting'' times and study the time dependence of the spectral features. Characteristic signatures of exciton polarization correlations manifest in the diagonal peaks decay at the exciton dephasing rate, consistent with theoretical predictions. Other many-body interactions manifest in off-diagonal features decay much more slowly. These persistent off-diagonal features must be due to many-body interactions involving exciton populations, and their persistence cannot be predicted by theoretical descriptions restricted to the coherent limit.