cssi/SciSciGPT-SciSciNet huggingface dataset:
Corporate Reorganizations and Non-Cash Auctions

This paper extends the theory of non-cash auctions by considering the revenue and efficiency of using different securities. Research on bankruptcy and privatization suggests using non-cash auctions to increase cash-constrained bidder participation. We examine this proposal and demonstrate that securities may lead to higher revenue. However, bidders pool unless bids include debt, which results in possible repossession by the seller. This suggests all-equity outcomes are unlikely and explains the high debt of reorganized firms. Securities also inefficiently determine bidders' incentive contracts and the firm's capital structure. Therefore, we recommend a new cash auction for an incentive contract.
The Half-Life of Policy Rationales: How New Technology Affects Old Policy Issues

part i Metering, Excluding, and Charging1 Technology, Marine Conservation, and Fisheries Management2 The Lighthouse as a Private-Sector Collective Good3 Motorway Financing and Provision: Technology Favors a New Approach4 Buying Time at the Curb5 Fencing the Airshed: Using Remote Sensing to Police Auto Emissionspart ii Quality Assurance and Consumer Protection6 Technology and the Case for Free Banking7 Consumer Protection Regulation and Information on the Internet8 Medical Licensing: Existing Public Policy and Technological Changepart iii Natural Monopoly?9 Technology and Electricity: Overcoming the Umbilical Mentality10 Avoiding the Grid: Technology and the Decentralization of Water11 Technological Change and the Case for Government Intervention in Postal Servicespart iv Other Areas of Policy12 The Entrepreneurial Community in Light of Advancing Business Practices and Technologies13 Technology and the Protection of Endangered Species
Kinetics of particle nucleation and growth in the emulsion polymerization of acrylic monomers

The rates of particle formation and growth during the earliest stages of the emulsion polymerization of several acrylic monomers have been studied as a function of surfactant concentration by means of the time-dependence of light scattering from the reaction mixtures. Investigated were methyl methacrylate, and methyl, ethyl, and butyl acrylates at concentrations of SDS surfactant from zero to several times the CMC. Under continuous photoinitiation, the Rayleigh scattering intensities rose rapidly with slopes that increased with decreasing SDS concentration. The more water-soluble the monomer, the more slowly was the rate of increase in scattering intensity.
Physics design of the high brightness linac for the advanced free-electron laser initiative at Los Alamos

Abstract Free-electron lasers and high energy physics accelerators have increased the demand for very high brightness electron-beam sources. This paper describes the design of an accelerator that can produce beams of greater than 7×10 11 A/m 2 (brightness equal to 21/ϵ 2 , with ϵ = 90% normalized emittance, equivalent to four times the rms emittance). The beam emittance growth in the accelerator is minimized by: producing a short electron bunch in a high gradient rf cavity, using a focusing solenoid to correct the emittance growth caused by space charge, and designing the coupling slots between accelerator cavities to minimize quadrupole effects. The simulation code PARMELA was modified for this design effort. This modified version uses SUPERFISH output files for the accelerator cavity fields, MAFIA output files for the 3-D perturbation fields caused by the coupling slots in the accelerator cells, and POISSON output files for the solenoid field in the gun region. The results from simulations are, at 2.3 nC, a peak current of 180 A and a 90% emittance of 6.4π mm mrad, and, at 4 nC a peak current of 300 A and a 90% emittance of 9.4π mrad. The exit energy from the linac is 20 MeV for both cases. A magnetic pulse compressor can be used to further increase the peak current.
Simulating confidence for the Ellison–Glaeser index☆☆☆

Abstract The Ellison and Glaeser (1997) index is an unbiased statistic of industrial localization. Though the expected value of the index is known, ad hoc thresholds are used to interpret the extent of localization. We improve the interpretation of the index by simulating confidence intervals that a practitioner may use for a statistical test. In the data, we find cases whose index value is above the ad hoc threshold that are not statistically significant. We find many cases below the ad hoc threshold that are statistically significant. Our simulation program is freely available and is customizable for specific applications.
Why countries are fiscally decentralizing

This paper models and empirically investigates underlying forces that promote governmental decentralization, or effective federalism, in the world over the last 25 years. A move to a federal system is based on the demand by hinterland regions for local autonomy, which increases with national income growth, greater relative hinterland population, and increasing national population. It is influenced as well by the degree of democratization nationally and locally. Decentralization is measured by both institutional indices indicating greater devolution of power to local governments and the share of local governments in national government consumption. Empirically, the paper finds that decentralization changes in ways predicted, in particular it increases with economic growth, country size, and population. Institutional structures based on colonial experience and initial constitutional provisions also matter.
A note on effective lagrangians in matrix theory

Abstract We study the relation between the effective Lagrangian in Matrix Theory and eleven dimensional supergravity. In particular, we provide a relationship between supergravity operators and the corresponding terms in the post-Newtonian approximation of Matrix Theory.
Examining the “CSI-effect” in the cases of circumstantial evidence and eyewitness testimony: Multivariate and path analyses.

As part of a larger investigation of the changing nature of juror behavior in the context of technology development, this study examined important questions unanswered by previous studies on the “CSI-effect.” In answering such questions, the present study applied multivariate and path analyses for the first time. The results showed that (a) watching CSI dramas had no independent effect on jurors' verdicts, (b) the exposure to CSI dramas did not interact with individual characteristics, (c) different individual characteristics were significantly associated with different types of evidence, and (d) CSI watching had no direct effect on jurors' decisions, and it had an indirect effect on conviction in the case of circumstantial evidence only as it raised expectations about scientific evidence, but it produced no indirect effect in the case of eyewitness testimony only. Finally, implications of the present study as well as for future research on the “CSI-effect” on jurors are discussed.
Probing decisive answers to dark energy questions from cosmic complementarity and lensing tomography

We study future constraints on dark energy parameters determined from several combinations of cosmic microwave background experiments, supernova data, and cosmic-shear surveys with and without tomography. In this analysis, we look in particular for combinations of experiments that will bring the uncertainties to a level of precision tight enough (a few per cent) to answer decisively some of the questions regarding dark energy. In view of the parametrization dependence problems, we probe the dark energy using two variants of its equation of state w(z), and its energy density ρ de(z). For the latter, we model ρ de(z )a s acontinuous function interpolated using dimensionless parameters Ei (zi ) ≡ ρde(zi )/ρde(0). We consider a large set of 13 cosmological and systematic parameters, and assume reasonable priors on the lensing and supernova systematics. For the CMB, we consider future constraints from eight years of data from WMAP, one year of data from Planck, and one year of data from the Atacama Cosmology Telescope (ACT). We use two sets of 2000 supernovae with z max = 0.8 and 1.5 respectively, and consider various cosmic-shear reference surveys: a wide ground-based-like survey, covering 70 per cent of the sky, and with successively two and five tomographic bins; and a deep-space-based-like survey with 10 tomographic bins and various sky coverages. The 1σ constraints found are {σ (w0) = 0.086, σ (w1) = 0.069}, {σ (w0) = 0.088, σ (wa) = 0.11}, and {σ (E1) = 0.029 ,σ (E2) = 0.065} from Planck, supernovae and the ground-basedlike lensing survey with two bins. When five bins are used within the same combination the constraints reduce to {σ (w 0) = 0.04, σ (w1) = 0.034}, {σ (w0) = 0.041, σ (wa) = 0.056}, and {σ (E1) = 0.012 ,σ (E2) = 0.049}. Finally, when the deep lensing survey with 10 per cent coverage of the sky and 10 tomographic bins is used along with Planck and the deep supernova survey, the constraints reduce to {σ (w 0) = 0.032, σ (w1) = 0.027}, {σ (w0) = 0.033, σ (wa) = 0.04}, and {σ (E1) = 0.01 ,σ (E2) = 0.04}. Other coverages of the sky and other combinations of experiments are explored as well. Although some worries remain about other systematics, our study shows that, after the combination of the three probes, lensing tomography with many redshift bins and large coverages of the sky has the potential to add key improvements to the dark energy parameter constraints. However, the fact that very ambitious and sophisticated surveys are required in order to achieve some of these constraints or to improve them suggests the need for new tests to probe the nature of dark energy in addition to constraining its equation of state. Ke yw ords: gravitational lensing ‐ cosmology: theory ‐ dark matter ‐ large-scale structure of Universe.
First examples of stable arenium ions from large methylene-bridged polycyclic aromatic hydrocarbons (PAHs). Directive effects and charge delocalization mode.

In connection to a growing interest in developing structure/activity trends in nonalternant polyarenes, we report on the generation and NMR studies of the first series of persistent arenium ions from large methylene-bridged PAHs (mostly 22π six-fused ring systems). Low-temperature protonation (FSO3H/SO2ClF) and model nitration (with HNO3/HOAc or NO2+ BF4-) were used as mimic reactions for generation of biological electrophiles. The site(s) of protonation (and nitration) were determined as a function of PAH structure. Charge delocalization mode in the resulting arenium ions of protonation are assessed based on detailed low-temperature NMR studies at 500 MHz. Systems studied were 1-methylcyclopenta[def]phenanthrene 2, 11H-benz[bc]aceanthrylene 8, 5H-benzo[b]cyclopenta[def]chrysene 9, 13H-dibenzo-[bc,l]aceanthrylene 10, 13H-cyclopenta[rst]pentaphene 11, 4H-benzo[b]cyclopenta[mno]chrysene 12, 6H-cyclopenta[ghi]picene 13, 4H-cyclopenta[pqr]picene 14, 4H-cyclopenta[def]dibenz[a,c]anthracene 15. For comparison, ...
Hypoelliptic heat kernel inequalities on Lie groups

Abstract This paper discusses the existence of gradient estimates for the heat kernel of a second order hypoelliptic operator on a manifold. For elliptic operators, it is now standard that such estimates (satisfying certain conditions on coefficients) are equivalent to a lower bound on the Ricci tensor of the Riemannian metric. For hypoelliptic operators, the associated “Ricci curvature” takes on the value − ∞ at points of degeneracy of the semi-Riemannian metric. For this reason, the standard proofs for the elliptic theory fail in the hypoelliptic setting. This paper presents recent results for hypoelliptic operators. Malliavin calculus methods transfer the problem to one of determining certain infinite dimensional estimates. Here, the underlying manifold is a Lie group, and the hypoelliptic operators are given by the sum of squares of left invariant vector fields. In particular, “ L p -type” gradient estimates hold for p ∈ ( 1 , ∞ ) , and the p = 2 gradient estimate implies a Poincare estimate in this context.
Inverse Bremsstrahlung in Shocked Astrophysical Plasmas

There has recently been interest in the role of inverse bremsstrahlung, the emission of photons by fast suprathermal ions in collisions with ambient electrons possessing relatively low velocities, in tenuous plasmas in various astrophysical contexts. This follows a long hiatus in the application of suprathermal ion bremsstrahlung to astrophysical models since the early 1970s. The potential importance of inverse bremsstrahlung relative to normal bremsstrahlung, i.e. where ions are at rest, hinges upon the underlying velocity distributions of the interacting species. In this paper, we identify the conditions under which the inverse bremsstrahlung emissivity is significant relative to that for normal bremsstrahlung in shocked astrophysical plasmas. We determine that, since both observational and theoretical evidence favors electron temperatures almost comparable to, and certainly not very deficient relative to proton temperatures in shocked plasmas, these environments generally render inverse bremsstrahlung at best a minor contributor to the overall emission. Hence inverse bremsstrahlung can be safely neglected in most models invoking shock acceleration in discrete sources such as supernova remnants. However, on scales approximately > 100 pc distant from these sources, Coulomb collisional losses can deplete the cosmic ray electrons, rendering inverse bremsstrahlung, and perhaps bremsstrahlung from knock-on electrons, possibly detectable.
Analytic model for galaxy and dark matter clustering

We investigate an analytic model to compute the non-linear power spectrum of dark matter, galaxies and their cross-correlation. The model is based on Press–Schechter haloes, which cluster and have realistic dark matter profiles. The total power spectrum is a sum of two contributions, one from correlations between the haloes and one from correlations within the same halo. We show that such a model can give dark matter power spectra which match well with the results of N-body simulations, provided that the concentration parameter decreases with the halo mass. The galaxy power spectrum differs from the dark matter power spectrum because the pair-weighted number of galaxies does not scale with the halo mass and because most haloes harbour a central galaxy. If the pair-weighted number of galaxies increases less rapidly than the halo mass, as predicted by theoretical models and observed in clusters, then the resulting power spectrum becomes a power law with a slope close to the observed over several orders of magnitude in scale. Such a model also predicts a later onset of non-linear clustering in comparison with dark matter, which is needed to reconcile the cold dark matter (CDM) models with the data. A generic prediction of this model is that bias is scale-dependent and non-monotonic. This is particularly important for red or elliptical galaxies, which are preferentially found in larger mass haloes and for which the bias in the power spectrum may be scale-dependent even on large scales. Our predictions for galaxy–dark matter correlations, which can be observed through galaxy–galaxy lensing, show that these cannot be interpreted simply as an average halo profile of a typical galaxy, because different halo masses dominate at different scales and because larger haloes host more than one galaxy. We compute predictions for the cross-correlation coefficient as a function of scale and discuss the prospects of using cross-correlations in combination with galaxy clustering to determine the dark matter power spectrum.
A technique for analytical calculation of observables in lattice gauge theories

Abstract It is shown that the partition function for a finite lattice factorizes into terms that can be associated with each vertex in the finite lattice. This factorization property forms the basis of a well-defined and efficient technique developed to calculate partition functions to high accuracy, on finite lattices for gauge theories. This technique, along with an expansion in finite lattices, provides a powerful means for calculating observables in lattice gauge theories. This is applied to SU(2) lattice gauge theory in four dimensions. The free energy, expectation value of a plaquette and specific heat are calculated. The results are very good both in the strong coupling and the weak coupling region and describe the crossover region quite well, agreeing all the way with the Monte Carlo data.
Cosmological searches for photon velocity oscillations

Abstract We posit a second massless photon, uncoupled to known forms of matter but undergoing Lorentz non-invariant velocity mixing with ordinary photons. Our speculation within a speculation suffers from the sin of implausibility but enjoys the virtue of verifiability. To avoid unacceptable distortion of the well-measured microwave background spectrum, the velocity difference of the photons cannot exceed ∼10 −32 c . Stronger constraints (or observable effects!) can arise from optical measurements of distant sources.
A no‐net‐rotation model of present‐day surface motions

A significant portion of the Earth's surface consists of zones of diffuse deformation. The interior regions of these diffuse zones of deformation move at distinctly different velocities from that of adjacent plates, and, because of their complexities, have been ignored in previous no-net-rotation (NNR) models. We have calculated a new NNR model from a continuous velocity field that incorporates both rigid plate motion and velocity gradients within plate boundary zones. When compared with earlier NNR models we find significantly different angular velocities for many plates. Differences between the NNR model presented here and earlier NNR models can be attributed to the effect of including velocity gradients in diffuse plate boundary zones as well as to the actual differences between geodetically derived surface motions and geologic estimates.
The work disincentive effects of the disability insurance program in the 1990s

Abstract In this paper we evaluate the work disincentive effects of the disability insurance (DI) program during the 1990s using comparison group and regression-discontinuity methods. The latter approach exploits a particular feature of the DI eligibility determination process to estimate the program's impact on labor supply for an important subset of DI applicants. Using merged survey-administrative data, we find that during the 1990s the labor force participation rate of DI beneficiaries would have been at most 20 percentage points higher had none received benefits. In addition, we find even smaller labor supply responses for the subset of ‘marginal’ applicants whose disability determination is based on vocational factors.
Strict p -negative type of a metric space

Doust and Weston (J Funct Anal 254:2336–2364, 2008) have introduced a new method called enhanced negative type for calculating a non-trivial lower bound $${\wp_{T}}$$ on the supremal strict p-negative type of any given finite metric tree (T, d). In the context of finite metric trees any such lower bound $${\wp_{T} >1 }$$ is deemed to be non-trivial. In this paper we refine the technique of enhanced negative type and show how it may be applied more generally to any finite metric space (X, d) that is known to have strict p-negative type for some p ≥ 0. This allows us to significantly improve the lower bounds on the supremal strict p-negative type of finite metric trees that were given in Doust and Weston (J Funct Anal 254:2336–2364, 2008, Corollary 5.5) and, moreover, leads in to one of our main results: the supremal p-negative type of a finite metric space cannot be strict. By way of application we are then able to exhibit large classes of finite metric spaces (such as finite isometric subspaces of Hadamard manifolds) that must have strict p-negative type for some p > 1. We also show that if a metric space (finite or otherwise) has p-negative type for some p > 0, then it must have strict q-negative type for all $${q \in [0, p)}$$ . This generalizes Schoenberg (Ann Math 38:787–793, 1937, Theorem 2) and leads to a complete classification of the intervals on which a metric space may have strict p-negative type.
Long-term testing of advanced ceramics : Concerns, insights, and recommendations

Advanced ceramics have reached a level of material development to warrant serious consideration for use in advanced heat engine designs. Typically, design requirements based on service conditions may include 25,000 h lifetimes under stresses and temperatures of up to 250 MPa and 1370°C, respectively, with probabilities of failure of 10,000 h) and load control (gravity-controlled, dead load), and responsive data acquisition systems (12-bit, digital collection). Data thus obtained can be used as input into design codes such as NASA CARES/LIFE to predict and confirm reliability/durability.
Spectral Consequences of Deviation from Spherical Composition Symmetry in Type Ia Supernovae

We investigate the prospects for constraining the maximum scale of clumping in composition that is consistent with observed Type Ia supernova flux spectra. Synthetic spectra generated without purely spherical composition symmetry indicate that gross asymmetries make prominent changes to absorption features. Motivated by this, we consider the case of a single unblended line forming in an atmosphere with perturbations of different scales and spatial distributions. Perturbations of about 1% of the area of the photodisk simply weaken the absorption feature by the same amount independent of the line of sight. Conversely, perturbations of about 10% of the area of the photodisk introduce variation in the absorption depth that does depend on the line of sight. Thus, 1% photodisk area perturbations may be consistent with observed profile homogeneity, but 10% photodisk area perturbations cannot. Based on this, we suggest that the absence of significant variation in the depths of Si II λ6355 absorption features in normal Type Ia spectra near maximum light indicates that any composition perturbations in these events are quite small. This also constrains future three-dimensional explosion models to produce ejecta profiles with only small-scale inhomogeneities.
Endogenous opioid regulation of gonadotropin-releasing hormone release from the human fetal hypothalamus in vitro

Endogenous opioid regulation of GnRH release from the human fetal (21–23 weeks gestation) mediobasal hypothalamus was investigated in an in vitro perifusion system. Pulse injection of an opiate receptor antagonist, naloxone, reproducibly elicited an acute increase in GnRH release within 30 min. Constant infusion of naloxone (60 min) induced a sustained increase in GnRH release, which was promptly inhibited by a pulse of β-endorphin administered halfway during the naloxone infusion. These studies unequivocally demonstrate that endogenous opiates exert an inhibitory effect on GnRH release from the human fetal mediobasal hypothalamus in vitro.
Renormalization of Entanglement Entropy and the Gravitational Effective Action

The entanglement entropy of quantum fields across a spatial boundary is UV divergent, its leading contribution proportional to the area of this boundary. We demonstrate that the Callan-Wilczek formula provides a renormalized geometrical definition of this entanglement entropy for a class of quantum states defined by a path integral over quantum fields propagating on a curved background spacetime. In particular, UV divergences localized on the spatial boundary do not contribute to the entanglement entropy, the leading contribution to the renormalized entanglement entropy is given by the Bekenstein-Hawking formula, and subleading UV-sensitive contributions are given in terms of renormalized couplings of the gravitational effective action. These results hold even if the UV-divergent contribution to the entanglement entropy is negative, for example, in theories with non-minimal scalar couplings to gravity. We show that subleading UV-sensitive contributions to the renormalized entanglement entropy depend nontrivially on the quantum state. We compute new subleading UV-sensitive contributions to the renormalized entanglement entropy, finding agreement with the Wald entropy formula in all cases. We speculate that the entanglement entropy of an arbitrary spatial boundary may be a well-defined observable in quantum gravity.
Intermolecular C−O Addition of Carboxylic Acids to Arynes

A novel, efficient, and expedient route to biologically and pharmaceutically important o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones has been developed starting from readily available carboxylic acids and commercially available o-(trimethylsilyl)aryl triflates.
Oxidative carbonylation of amines to formamides using NaIO4

Carbonylation of amines in methanol in the presence of NaIO4 produces formamide derivatives in good to excellent yields without a transition metal catalyst.
A new approach to optimum sizing and in-orbit utilization of spacecraft photovoltaic power systems

Abstract This paper presents a systems approach to optimization of the size and orbital life of photovoltaic systems via minimizing the nighttime energy demand while maximizing the daytime energy consumption. The Day-Night Management of Load (DANMOE) strategy calls for sizing the system to a pre-selected day/night average load power ratio and operating the spacecraft in orbit within the day and night capacity capability, rather than the conventional single orbital average power capability. Examples for the Space Station and the telecommunication satellites show that the reduction in their specific masses can be substantial using any of the photovoltaic system technologies. The DANMOE scheme may also be used effectively to extend the life of batteries on currently orbiting satellites, and hence prolong their lifetime. The paper also discusses other benefits at the spacecraft level and the method of implementing the DANMOE approach.
Dynamic Retrospective Regression for Functional Data

Samples of curves, or functional data, usually present phase variability in addition to amplitude variability. Existing functional regression methods do not handle phase variability in an efficient way. In this article we propose a functional regression method that incorporates phase synchronization as an intrinsic part of the model, and then attains better predictive power than ordinary linear regression in a simple and parsimonious way. The finite-sample properties of the estimators are studied by simulation. As an example of application, we analyze neuromotor data arising from a study of human lip movement. This article has supplementary materials online.
Bladder cancer in spinal cord injury patients

Retrospective review. Spinal cord injury is a known risk factor for bladder cancer. The risk of bladder cancer has been reported at 16–28 times higher than the general population. Earlier studies have identified indwelling catheters as risk factors. We examined the characteristics of bladder cancers in a spinal cord injury (SCI) population. Long Beach VA Hospital Spinal Cord Injury Unit, Long Beach, California We reviewed SCI patients seen and diagnosed with bladder tumors between January 1983 and January 2007. Data collected included time since diagnosis, method of diagnosis, form of bladder management, pathologic type, treatment of the tumor, and outcome. A total of 32 patients with bladder cancer were identified out of 1319 seen. Tumors found were 46.9% squamous cell carcinoma (SCC), 31.3% transitional cell carcinoma (TCC), 9.4% adenocarcinoma, and 12.5% mixed TCC and SCC. The primary form of bladder management was 44% urethral catheter for a mean of 33.3 years, 48% external catheter for a mean of 37.4 years, and 8% intermittent catheterization for a mean of 24.5 years. Nineteen patients had a known method of cancer detection with 42% found on screening cystoscopy. The pathologic makeup of the tumors is similar to that reported earlier. Over 50% of patients diagnosed with bladder cancer in our population did not have an indwelling catheter. This suggests that the neurogenic bladder, not the indwelling catheter, may be the risk factor for bladder cancer. Urologists should consider diligent, long-term screening of all patients with SCI for bladder cancer and not just those with indwelling catheters.
Fundamentals on the Noncommutative Plane

We consider the addition of charged matter (``fundametals'') to noncommutative Yang-Mills theory and noncommutative QED, derive Feynman rules and tree-level potentials for them, and study the divergence structure of the theory. These particles behave very much as they do in the commutative theory, except that (1) they occupy bound-state wavefunctions which are essentially those of charged particles in magnetic fields, and (2) there is slight momentum nonconservation at vertices. There is no reduction in the degree of divergence of charged fermion loops like that which affects nonplanar noncommutative Yang-Mills diagrams.
Synthesis and tautomerism of ethyl 2‐(2‐benzothiazolyl)‐2‐(6‐purinyl)acetate and related compounds

Reaction of 6-chloro-9H-(2-tetrahydropyranyl)purine (2d) with the sodium salt of ethyl benzothiazole-2-ace-tate (1) in dimethylformamide effects condensation of the two compounds (with loss of sodium chloride) to give the corresponding ethyl diarylacetate 4 (35%), present largely as an enol chelate tautomer. Isolated as a by-product is 6-(2-aminophenyl-1-thio)-9H-(2-tetrahydropyranyl)-purine (4%), formed via opening of the thiazole ring. Removal of the tetrahydropyranyl protective group from 4 occurs by treatment with p-toluenesulfonic acid in aqueous ethanol to produce ethyl benzothiazole-2-(6-purinyl)acetate (80%), existent largely as two enol chelate isomers. Spectral data for the various products are presented. An attempt to use 6-chloro-9-acetyl-9H-purine in place of 2d in the first reaction gives acetylation of 1 instead of condensation.
Re-Engineering the Design Process Through Computation

This paper reviews the use of computational flow simulation for aircraft design. While computational simulation has already yielded great benefits, its impact continues to be restricted by computational and human costs. The requirements of the design process are examined in detail. In current practice there are bottlenecks in geometry modelling, data handling and mesh generation. To exploit computational simulation more effectively there is also a need to combine it with automatic optimization procedures. A case study is presented of a recent industrial experience with optimization. Finally it is suggested that developments in information technology now offer the opportunity to produce an integrated numerical design environment, and to re-engineer the design process.
Linear relations among Poincaré series via harmonic weak Maass forms

We discuss the problem of the vanishing of Poincare series. This problem is known to be related to the existence of weakly holomorphic forms with prescribed principal part. The obstruction to the existence is related to the pseudomodularity of Ramanujan’s mock theta functions. We embed the space of weakly holomorphic modular forms into the larger space of harmonic weak Maass forms. From this perspective we discuss the linear relations between Poincare series.
Convenient Route to Di- and Triorganosilyl Ethyl Ethers and the Corresponding Di- and Triorganosilanes

Abstract Tetraetboxysilane was treated with alkyl- and aryllithium reagents for the preparation of organosilyl ethyl ethers of the type R 3 SiOEt, R 2 R′SiOEt, and R 2 Si(OEt) 2 , that can be reduced to the organosilanes R 3 SiH, R 2 R′SiH, and R 2 SiH 2 , respectively. Compounds of the type RR′R′SiOEt cannot be cleanly formed. The reduction procedure involves treatment of the silyl alkoxy ethers with diisobutylaluminium hydride (DIBALH) and hydrolysis of the remaining alkylaluminium compounds with Na 2 SO 4 ·10H 2 O. This hydrolysis provides a convenient method for the isolation of R 3 SiH, R 2 R′SiH, and R 2 SiH 2 compounds without hydrolysis of the SiH moiety that often occurs in standard aqueous work-up procedures of unhindered silanes.
Electromagnetic Levitation with Acoustic Modulation for Property Measurement

Nomenclature a = characteristic length of levitated material, m B,B = magnetic flux density, Wb/m2 cp = specific heat of levitated material (J/kg K) E = ohmic heating rate, W g ,g = gravitational acceleration 7 = moment of inertia, / = 2/5 ma2 /,/ = induced eddy current density (A/m2), /= 1/juV xB k = wave number of sound waves in the medium K = radius of curvature of deformed droplet, m m = mass of droplet, kg P = pressure, N/m2 Pm = mean magnetic pressure on the droplet surface, N/m2 Ps = pressure amplitude of acoustic standing wave P2o = quadrupole radial projection of acoustic radiation pressure
THE NATURE OF MAN

Understanding human behavior is fundamental to understanding how organizations function, whether they are profit-making firms, non-profit enterprises, or government agencies. Much disagreement among managers, scientists, policy makers, and citizens arises from substantial differences in the way we think about human nature—about their strengths, frailties, intelligence, ignorance, honesty, selfishness, and generosity. In this paper we discuss five alternative models of human behavior that are commonly used (though usually implicitly). They are the Resourceful, Evaluative, Maximizing Model (REMM), Economic (or Money Maximizing) Model, Psychological (or Hierarchy of Needs) Model, Sociological (or Social Victim) Model, and the Political (or Perfect Agent) Model. We argue that REMM best describes the systematically rational part of human behavior. It serves as the foundation for the agency model of financial, organizational, and governance structure of firms. The growing body of social science research on human behavior has a common message: Whether they are politicians, managers, academics, professionals, philanthropists, or factory workers, individuals are resourceful, evaluative maximizers. They respond creatively to the opportunities the environment presents, and they work to loosen constraints that prevent them from doing what they wish. They care about not only money, but about almost everything—respect, honor, power, love, and the welfare of others. The challenge for our society, and for all organizations in it, is to establish rules of the game that tap and direct human energy in ways that increase rather than reduce the effective use of our scarce resources.
Challenges and Opportunities for Applications of Unconventional Superconductors

Since the discovery of high-Tc cuprates, the quest for new superconductors has shifted toward more anisotropic, strongly correlated materials with lower carrier densities and competing magnetic and charge-density wave orders. Although these materials’ features enhance superconducting correlations, they also result in serious problems for applications at liquid nitrogen (and higher) temperatures and strong magnetic fields so that such conventional characteristics as the critical temperature Tc and the upper critical field Hc2 are no longer the main parameters of merit. This happens because of strong fluctuations of the order parameter, thermally activated hopping of pinned vortices, and electromagnetic granularity, as has been established after extensive investigations of cuprates and Fe-based superconductors (FBSs). In this paper, I give an overview of those mechanisms crucial for power and magnet applications and discuss the materials’ restrictions that must be satisfied to make superconductors useful at...
FAST SOFTWARE FOR BOX INTERSECTIONS

We present fast implementations of a hybrid algorithm for reporting box and cube intersections. Our algorithm initially takes a divide-and-conquer approach and switches to simpler algorithms for low numbers of boxes. We use our implementations as engines to solve problems about geometric primitives. We look at two such problems in the category of quality analysis of surface triangulations.
Retrospective analysis of the incidence of epidural haematoma in patients with epidural catheters and abnormal coagulation parameters

Background Epidural haematoma is a rare but potentially catastrophic complication associated with epidural catheterization. The times of insertion and removal of epidural catheters are high-risk periods for epidural haematoma formation, especially with abnormal coagulation parameters. There is a lack of data on the incidence of epidural haematoma in patients with abnormal coagulation parameters. Methods A retrospective analysis was undertaken from 2002 to 2009 on patients with an epidural catheter. Queries were performed on the coagulation parameters for the dates of placement and removal of the catheters and on all documented epidural haematoma cases. Results During the study period, 11 600 epidural catheters were placed. In the setting of abnormal coagulation parameters, 278 (2.4%) epidural catheters were placed and 351 (3%) were removed. Two epidural haematomas occurred; both patients had epidural catheters and spinal drains placed for vascular procedures with abnormal coagulation parameters after operatation. The haematomas occurred after removal of the catheters. Based on our study, the incidence of epidural haematoma in patients with abnormal coagulation parameters is 1 in 315 patients, with the lower limit of the 95% confidence interval at 87 and the upper limit at 2597. Conclusions The risk of epidural haematoma is clearly elevated with abnormal coagulation parameters. Our data suggest that as the incidence of epidural haematoma with neuraxial access in patients with abnormal coagulation is not 100%, individual risk–benefit evaluations are warranted.
Nonlinear resonances in the solar system

Orbital resonances are ubiquitous in the Solar system. They play a decisive role in the long term dynamics, and in some cases the physical evolution, of the planets and of their natural satellites, as well as the evolution of small bodies (including dust) in the planetary system. The few-body gravitational problem of hierarchical planetary-type systems allows for a complex range of dynamical timescales, from the fast orbital periods to the very slow orbit precession rates. The interaction of fast and slow degrees of freedom produces a rich diversity of resonance phenomena. Weak dissipative effects - such as tides or radiation drag forces - also produce unexpectedly rich dynamical behaviors. This paper provides a mostly qualitative discussion of simple dynamical models for the commonly encountered orbital resonance phenomena in the Solar system.
Opportunistic Scheduling with Reliability Guarantees in Cognitive Radio Networks

We develop opportunistic scheduling policies for cognitive radio networks that maximize the throughput utility of the secondary (unlicensed) users subject to maximum collision constraints with the primary (licensed) users. We consider a cognitive network with static primary users and potentially mobile secondary users. We use the technique of Lyapunov optimization to design an online flow control, scheduling, and resource allocation algorithm that meets the desired objectives and provides explicit performance guarantees.
Optimizing queries over multimedia repositories

Repositories of multimedia objects having multiple types of attributes (e.g., image, text) are becoming increasingly common. A selection on these attributes will typically produce not just a set of objects, as in the traditional relational query model (filtering), but also a grade of match associated with each object, indicating how well the object matches the selection condition (ranking). Also, multimedia repositories may allow access to the attributes of each object only through indexes. We investigate how to optimize the processing of queries over multimedia repositories. A key issue is the choice of the indexes used to search the repository. We define an execution space that is search-minimal, i.e., the set of indexes searched is minimal. Although the general problem of picking an optimal plan in the search-minimal execution space is NP-hard, we solve the problem efficiently when the predicates in the query are independent. We also show that the problem of optimizing queries that ask for a few top-ranked objects can be viewed, in many cases, as that of evaluating selection conditions. Thus, both problems can be viewed together as an extended filtering problem.
Requirements for the development of computer-based urban information systems

Since early in this decade urban planners and systems analysts have advocated the development of computer-based urban information systems. Such systems would store detailed data about the environment in which planning agencies and governments operate. They would be organized to lend integration to data from diverse sources, to provide quick preparation of reports and to simplify and automate numerous clerical functions. Many attempts have been made to develop urban information systems with the characteristics mentioned above. Most have been unsuccessful for a combination of technical and organizational reasons. This paper considers some technical requirements for planning information systems which deal with data associated with urban locations. The requirements are developed on the basis of experience in providing a prototype urban information system to the Boston Model Cities program. The next section describes briefly the experience of providing an infoimation system to the Boston Model Cities program. Succeeding sections draw on this experience to develop general technical requirements for urban information systems. A technique for aggregating data by geographic area is presented and its implications for system file structure and utilization are explored.
Active Disturbance Rejection Control for MEMS Gyroscopes

A new control method is presented to drive the drive axis of a Micro-Electro-Mechanical Systems (MEMS) gyroscope to resonance and to regulate the output amplitude of the axis to a fixed level. It is based on a unique active disturbance rejection control (ADRC) strategy, which actively estimates and compensates for internal dynamic changes of the drive axis and external disturbances in real time. The stability analysis shows that both the estimation error and the tracking error of the drive axis output are bounded and that the upper bounds of the errors monotonously decrease with the increase of the controller bandwidth. The control system is simulated and tested using a field-programmable-gate-array-based digital implementation on a piezoelectric vibrational gyroscope. Both simulation and experimental results demonstrate that the proposed controller not only drives the drive axis to vibrate along the desired trajectory but also compensates for manufacture imperfections in a robust fashion that makes the performance of the gyroscope insensitive to parameter variations and noises. Such robustness, the fact that the control design does not require an accurate plant model, and the ease of implementation make the proposed solution practical and economic for industrial applications.
Interface recombination velocity measurement by a contactless microwave technique

The interface or surface recombination velocity is a critical and important, parameter in many device applications. In this work. we have developed and applied a contactless microwave technique. which in combination with a continuously tunable pulsed light source. is able to probe the excess carrier life-time in the surface and bulk regions of it semiconductor wafer. The technique is called resonant coupled photoconductive decay (RCPCD) and has been described by the authors in the literature. For strongly absorbed light, the initial (t = 0) decay time is a strong function of the absorption coefficient, α, as well as the bulk lifetime. The effective bulk lifetime is a well-known function of the two surfaces (interfaces) and the true bulk lifetime. The effective bulk lifetime is measured by using very weakly absorbed light, or by measuring the asymptotic decay rate of strongly absorbed light. The latter occurs after diffusion has produced a quasi-equilibrium condition in the wafer. For asymmetric surfaces (such as a wafer polished on one surface only), the measurement with strongly absorbed light is made at both wafer surfaces. We have solved simultaneuously three nonlinear equations and the solutions provide values for the three unknowns S 1 , S 2 and τ(bulk). Several examples of the technique will he demonstrated for silicon wafers.
Hole Detection and Shape-Free Representation and Double Landmarks Based Geographic Routing in Wireless Sensor Networks

In wireless sensor networks, an important issue of geographic routing is “local minimum” problem, which is caused by a “hole” that blocks the greedy forwarding process. Existing geographic routing algorithms use perimeter routing strategies to find a long detour path when such a situation occurs. To avoid the long detour path, recent research focuses on detecting the hole in advance, then the nodes located on the boundary of the hole advertise the hole information to the nodes near the hole. Hence the long detour path can be avoided in future routing. We propose a heuristic hole detecting algorithm which identifies the hole easily and quickly and then propose a representation of hole no matter what the shape of the hole is. In addition, we quantitatively figure out the areas in the vicinity of the hole that need to be announced the hole information. With such information, a new routing scheme with two landmarks was developed. Simulation results illustrate that our approach can achieve better performance in terms of the average length and number of hops in routing paths. Simulation also shows that our approach introduces very small computational complexity.
The Economics of IPR Protection Policies

In this paper, I model competition between legal and pirate products. In this framework, the government affects competition through police spending and taxes on the legal products. Therefore, the government can choose the optimal combination of spending and taxes that fit better its goals. I show that governments focusing on eradicating piracy will use lower level of taxes and police spending than governments focused on maximizing consumption, consumer surplus, and welfare or government size. This result highlights the importance of demand side policies in the fight against piracy and challenges the traditional solo approach of supply side policies.
Ni(II) Salts and 2-Propanol Effect Catalytic Reductive Coupling of Epoxides and Alkynes

A Ni-catalyzed reductive coupling of alkynes and epoxides using Ni(II) salts and simple alcohol reducing agents is described. Whereas previously reported conditions relied on Ni(cod)2 and Et3B, this system has several advantages including the use of air-stable and inexpensive Ni(II) precatalysts (e.g., NiBr2·3H2O) as the source of Ni(0) and simple alcohols (e.g., 2-propanol) as the reducing agent. Deuterium-labeling experiments are consistent with oxidative addition of an epoxide C–O bond that occurs with inversion of configuration.
Round-Based Public Transit Routing

We study the problem of computing all Pareto-optimal journeys in a dynamic public transit network for multiple criteria, such as arrival time and number of transfers. Existing algorithms consider this as a graph problem and solve it using various graph search algorithms. Unfortunately, this leads to either high query times or suboptimal solutions. We take a different approach. We introduce RAPTOR, our novel round-based public transit router. Unlike previous algorithms, it is not Dijkstra-based, looks at each route such as a bus line in the network at most once per round, and can be made even faster with simple pruning rules and parallelization using multiple cores. Because it does not rely on preprocessing, RAPTOR works in fully dynamic scenarios. Starting from arrival time and number of transfers as criteria, it can be easily extended to handle flexible departure times or arbitrary additional criteria. As practical examples we consider fare zones and reliability of transfers. When run on complex public transportation networks such as London, RAPTOR computes all Pareto-optimal journeys between two random locations an order of magnitude faster than previous approaches, which easily enables interactive applications.