cssi/SciSciGPT-SciSciNet huggingface dataset:
On the hardness of approximate reasoning

Abstract Many AI problems, when formalized, reduce to evaluating the probability that a propositional expression is true. In this paper we show that this problem is computationally intractable even in surprisingly restricted cases and even if we settle for an approximation to this probability. We consider various methods used in approximate reasoning such as computing degree of belief and Bayesian belief networks, as well as reasoning techniques such as constraint satisfaction and knowledge compilation, that use approximation to avoid computational difficulties, and reduce them to model-counting problems over a propositional domain. We prove that counting satisfying assignments of propositional languages is intractable even for Horn and monotone formulae, and even when the size of clauses and number of occurrences of the variables are extremely limited. This should be contrasted with the case of deductive reasoning, where Horn theories and theories with binary clauses are distinguished by the existence of linear time satisfiability algorithms. What is even more surprising is that, as we show, even approximating the number of satisfying assignments (i.e., “approximating” approximate reasoning), is intractable for most of these restricted theories. We also identify some restricted classes of propositional formulae for which efficient algorithms for counting satisfying assignments can be given.
Direct, Redox-Neutral Prenylation and Geranylation of Secondary Carbinol C–H Bonds: C4-Regioselectivity in Ruthenium-Catalyzed C–C Couplings of Dienes to α-Hydroxy Esters

The ruthenium catalyst generated in situ from Ru3(CO)12 and tricyclohexylphosphine, PCy3, promotes the redox-neutral C–C coupling of aryl-substituted α-hydroxy esters to isoprene and myrcene at the diene C4-position, resulting in direct carbinol C–H prenylation and geranylation, respectively. This process enables direct conversion of secondary to tertiary alcohols in the absence of stoichiometric byproducts or premetalated reagents, and is the first example of C4-regioselectivity in catalytic C–C couplings of 2-substituted dienes to carbonyl partners. Mechanistic studies corroborate a catalytic cycle involving diene–carbonyl oxidative coupling.
Form factors of excited baryons at high Q2 and the transition to perturbative QCD

Abstract The relationship between the Q 2 dependence of transition form factors of excited baryons and perturbative QCD is discussed. New form factors have been extracted from existing exclusive electron scattering data up to Q 2 ∼ 10 GeV 2 /c 2 , and compared with pQCD expectations. It is concluded that exclusive experiments at high Q 2 will be essential for resolving outstanding issues, and the potential for these measurements with a new electron accelerator facility is discussed.
Pure-tone equal-loudness contours for standard tones of different frequencies

Six Ss made judgments of equal loudness by adjusting the intensity of comparison tones of 10 different frequencies. The comparison tones were presented diotically alternately with standaxd tones. Each standard tone remained fixed at one frequency (125, 1,000, or 8,000 Hz) and one intensity (10, 20, 40, or 70 dB sensation level)while collecting the data for any single equal-loudness contour. In this manner, families of equal-loudness contours were generated for each of the three standard frequencies. The contours for the 1,000-Hz standard were compared with those in the literature. The families of contours for the 125- and 8,000-Hz standards, determined by the same algorithm, differed in the spacing of the contours from the 1,000-Hz standard family as well as from each other. Implications for the reflexive, symmetric, and transitive properties of the equal-loudness relation axe discussed.
Asymmetry in the Presence of Migration Stabilizes Multistrain Disease Outbreaks

We study the effect of migration between coupled populations, or patches, on the stability properties of multistrain disease dynamics. The epidemic model used in this work displays a Hopf bifurcation to oscillations in a single, well-mixed population. It is shown numerically that migration between two non-identical patches stabilizes the endemic steady state, delaying the onset of large amplitude outbreaks and reducing the total number of infections. This result is motivated by analyzing generic Hopf bifurcations with different frequencies and with diffusive coupling between them. Stabilization of the steady state is again seen, indicating that our observation in the full multistrain model is based on qualitative characteristics of the dynamics rather than on details of the disease model.
Gorensteinness of Invariant Subrings of Quantum Algebras

Abstract We prove Auslander–Gorenstein and GKdim–Macaulay properties for certain invariant subrings of some quantum algebras, the Weyl algebras, and the universal enveloping algebras of finite-dimensional Lie algebras.
Fabrication of High-Performance LDDFET's with Oxide Sidewall-Spacer Technology

A fabrication process for the Lightly Doped Drain/Source Field-Effect Transistor, LDDFET, that utilizes RIE produced SiO/sub 2/ sidewall spacers is described. The process is compatible with most conventional polysilicon-gated FET processes and needs no additional photo-masking steps. Excellent control and reproducibility of the n/sup -/ region of the LDD device are obtained. Measurements from dynamic clock generators have shown that LDDFET's have as much as 1.9x performance advantage over conventional devices.
Electric polarizability of neutral hadrons from dynamical lattice QCD ensembles

We present a valence calculation of the electric polarizability of the neutron, neutral pion, and neutral kaon on two dynamically generated nHYP-clover ensembles. The pion masses for these ensembles are 227(2) MeV and 306(1) MeV, which are the lowest ones used in polarizability studies. This is part of a program geared towards determining these parameters at the physical point. We carry out a high statistics calculation that allows us to: (1) perform an extrapolation of the kaon polarizability to the physical point; we find $\alpha_K =0.269(43)\times10^{-4}$fm$^{3}$, (2) quantitatively compare our neutron polarizability results with predictions from $\chi$PT, and (3) analyze the dependence on both the valence and sea quark masses. The kaon polarizability varies slowly with the light quark mass and the extrapolation can be done with high confidence.
Structure and Magnetism of the Tetra-Copper(II)-Substituted Heteropolyanion [Cu4K2(H2O)8(α-AsW9O33)2]8-†

The novel heteropolyanion [Cu4K2(H2O)8(α-AsW9O33)2]8- (1) has been synthesized and characterized by IR spectroscopy, elemental analysis, and magnetic studies. Single-crystal X-ray analysis was carried out on {K7Na[Cu4K2(H2O)6(α-AsW9O33)2]·5.5H2O}n (K7Na-1), which crystallizes in the tetragonal system, space group P421m, with a = 16.705(4) A, b = 16.705(4) A, c = 13.956(5) A, and Z = 2. Interaction of the lacunary [α-AsW9O33]9- with Cu2+ ions in neutral, aqueous medium leads to the formation of the dimeric polyoxoanion 1 in high yield. Polyanion 1 consists of two α-AsW9O33 units joined by a cyclic arrangement of four Cu2+ and two K+ ions, resulting in a structure with C2v symmetry. All copper ions have one terminal water molecule, resulting in square-pyramidal coordination geometry. Three of the copper ions are adjacent to each other and connected via two μ3-oxo bridges. EPR studies on K7Na-1 and also on Na9[Cu3Na3(H2O)9(α-AsW9O33)2]·26H2O (Na9-2) over 2−300 K yielded g values that are consistent with a s...
Spectral Density on the Lattice

Abstract Spectral density in the pseudoscalar and vector channels is extracted from the SU(2) lattice quenched data. It is shown to consist of three sharp poles within the energy range accessible on the lattice.
A packetized direct load control mechanism for demand side management

Electricity peaks can be harmful to grid stability and result in additional generation costs to balance supply with demand. By developing a network of smart appliances together with a quasi-decentralized control protocol, direct load control (DLC) provides an opportunity to reduce peak consumption by directly controlling the on/off switch of the networked appliances. This paper proposes a packetized DLC (PDLC) solution that is illustrated by an application to air conditioning temperature control. Here the term packetized refers to a fixed time energy usage authorization. The consumers in each room choose their preferred set point, and then an operator of the local appliance pool will determine the comfort band around the set point. We use a thermal dynamic model to investigate the duty cycle of thermostatic appliances. Three theorems are proposed in this paper. The first two theorems evaluate the performance of the PDLC in both transient and steady state operation. The first theorem proves that the average room temperature would converge to the average room set point with fixed number of packets applied in each discrete interval. The second theorem proves that the PDLC solution guarantees to control the temperature of all the rooms within their individual comfort bands. The third theorem proposes an allocation method to link the results in theorem 1 and assumptions in theorem 2 such that the overall PDLC solution works. The direct result of the theorems is that we can reduce the consumption oscillation that occurs when no control is applied. Simulation is provided to verify theoretical results.
Ablative Thermal Response Analysis Using the Finite Element Method

*† A review of the classic techniques used to solve ablative thermal response problems is presented. The advantages and disadvantages of both the finite element and finite difference methods are described. As a first step in developing a three dimensional finite element based ablative thermal response capability, a one dimensional computer tool has been developed. The finite element method is used to discretize the governing differential equations and Galerkin’s method of weighted residuals is used to derive the element equations. A code to code comparison between the current 1-D finite element tool and the 1-D Fully Implicit Ablation and Thermal response program (FIAT), a NASA-standard finite difference tool, has been performed.
Microwave-assisted protocols for the expedited synthesis of pyrazolo[1,5-a] and [3,4-d]pyrimidines

General, high-yielding MAOS protocols for the expedited synthesis of functionalized pyrazolo[1,5-a]pyrimidines and pyrazolo[3,4-b]pyrimidines, as well as their pyrazole precursors, are described amenable to an iterative analogue library synthesis strategy for lead optimization.
Stability maps to predict anomalous ductility in B2 materials

While most B2 materials are brittle, a new class of B2 (rare-earth) intermetallic compounds is observed to have large ductility. We analytically derive a necessary condition for ductility (dislocation motion) involving $\ensuremath{\langle}111\ensuremath{\rangle}$ versus $\ensuremath{\langle}001\ensuremath{\rangle}$ slip and the relative stability of various planar defects that must form. We present a sufficient condition for antiphase boundary bistability on ${1\overline{1}0}$ and ${11\overline{2}}$ planes that allows multiple slip systems. From these energy-based criteria, we construct two stability maps for B2 ductility that use only dimensionless ratios of elastic constants and defect energies, calculated via density functional theory. These two conditions fully explain and predict enhanced ductility (or lack thereof) for B2 systems. In the 23 systems studied, the ductility of YAg, ScAg, ScAu, and ScPd, ductile-to-brittle crossover for other rare-earth B2 compounds, and brittleness of all classic B2 alloys and ionic compounds are correctly predicted.
Quasar Accretion Disks are Strongly Inhomogeneous

Active galactic nuclei have been observed to vary stochastically with 10%-20% rms amplitudes over a range of optical wavelengths where the emission arises in an accretion disk. Since the accretion disk is unlikely to vary coherently, local fluctuations may be significantly larger than the global rms variability. We investigate toy models of quasar accretion disks consisting of a number of regions, n, whose temperatures vary independently with an amplitude of {sigma}{sub T} in dex. Models with large fluctuations ({sigma}{sub T} = 0.35-0.50) in 10{sup 2}-10{sup 3} independently fluctuating zones for every factor of two in radius can explain the observed discrepancy between thin accretion disk sizes inferred from microlensing events and optical luminosity while matching the observed optical variability. For the same range of {sigma}{sub T}, inhomogeneous disk spectra provide excellent fits to the Hubble Space Telescope quasar composite without invoking global Compton scattering atmospheres to explain the high levels of observed UV emission. Simulated microlensing light curves for the Einstein cross from our time-varying toy models are well fit using a time-steady power-law temperature disk and produce magnification light curves that are consistent with current microlensing observations. Deviations due to the inhomogeneous, time-dependent disk structure should occur above themore » 1% level in the light curves, detectable in future microlensing observations with millimagnitude sensitivity.« less
Strongly coupled inorganic/nanocarbon hybrid materials for advanced electrocatalysis.

Electrochemical systems, such as fuel cell and water splitting devices, represent some of the most efficient and environmentally friendly technologies for energy conversion and storage. Electrocatalysts play key roles in the chemical processes but often limit the performance of the entire systems due to insufficient activity, lifetime, or high cost. It has been a long-standing challenge to develop efficient and durable electrocatalysts at low cost. In this Perspective, we present our recent efforts in developing strongly coupled inorganic/nanocarbon hybrid materials to improve the electrocatalytic activities and stability of inorganic metal oxides, hydroxides, sulfides, and metal–nitrogen complexes. The hybrid materials are synthesized by direct nucleation, growth, and anchoring of inorganic nanomaterials on the functional groups of oxidized nanocarbon substrates including graphene and carbon nanotubes. This approach affords strong chemical attachment and electrical coupling between the electrocatalytic n...
A novel protecting group for hindered phenols

Abstract Boc2O and DMAP were used to protect hindered phenols as their Boc derivatives under mild conditions. Deprotection conditions were developed to suppress loss of a tert-butyl group from the aromatic ring, or alkylation of an additional tert-butyl group at an unsubstituted ortho or para position.
Synthesis of Harmonic Motion Generating Linkages—Part I: Function Generation

Synthese d'un mecanisme generant un mouvement harmonique. Cas de la generation d'une fonction
Decoherence by Correlated Noise and Quantum Error Correction

We study the decoherence of a quantum computer in an environment which is inherently correlated in time and space. We first derive the nonunitary time evolution of the computer and environment in the presence of a stabilizer error correction code, providing a general way to quantify decoherence for a quantum computer. The general theory is then applied to the spin-boson model. Our results demonstrate that effects of long-range correlations can be systematically reduced by small changes in the error correction codes.
The selective functionalization of saturated hydrocarbons. Part 37. Utilization of a New Oxidant: Bis(trimethylsilyl) peroxide.

Abstract The selective oxidation of alkanes to ketones using FeIII(PA)3 and FeIII(PA)2Cl2, Pyr2H is performed with bis(trimethylsilyl) peroxided by a non radical mechanism. The FeIII-FeV manifold is responsible for the oxidation process. Without a suitable chelating ligand (PA), only formation of oxygen was observed.
Catalytic antibodies: hapten design strategies and screening methods

Catalytic antibodies have emerged as powerful tools for the efficient and specific catalysis of a wide range of chemical transformations. Generating antibody catalysts that achieve enzymatic efficiency remains a challenging task, which has long been the source of great interest both in the design of more effective haptens for immunization and in the development of more direct and efficient screening methods for the selection of antibodies with desired catalytic capacities. In this review, we describe the development of different hapten design strategies, including a transition state analog (TSA) approach, 'bait-and-switch' catalysis, and reactive immunization. We also comment on recent developments in the screening process that allow for a more efficient identification of antibody catalysts.
Public debt and full employment in a stock-flow consistent model of a corporate economy

This paper examines the fiscal requirements for continuous full employment. We find that (i) changes in the financial behavior of households and firms require adjustments in tax rates and public debt, (ii) the stability of the steady-growth solution for public debt depends on the fiscal instrument and the household consumption function, (iii) in stable cases, a fall in government consumption (or a decline in another component of autonomous demand) requires an increase in the steady-growth ratio of public debt to capital, and (iv) the steady-growth tax rate may be positively or negatively related to the level of debt.
Spectral bounds for the Hellmann potential

Abstract The method of potential envelopes is used to analyse the bound state spectrum of the Schrodinger Hamiltonian H=−Δ+V(r), where the Hellmann potential is given by V(r)=−A/r+Be−Cr/r, A and C are positive, and B can be positive or negative. We established simple formulas yielding upper and lower bounds for all the energy eigenvalues.
Cigarettes and addiction information: new evidence in support of the rational addiction model

Abstract A 1979 US Surgeon General’s report provided the first conclusive public information of nicotine’s addictive effects. We test the hypothesis that cigarette demand was of a ‘myopic’ nature prior to 1979, but forward-looking, or ‘rational’, thereafter.
Conformational statistics of the nitrogen linkage in glycopeptides using umbrella sampling

The conformational statistics of the glycosylated dipeptide N - acetyl - δ - N - (2 - acetamido - β - D - glucopyranosyl) - L - asparaginyl - N' - methyl amide (glcNAc-Asn), a model of N-linked glycopeptides, was determined using umbrella sampling. The use of umbrella sampling allowed the importance sampling algorithm to accept new conformations with probabilities exceeding 40%. The satisfactory acceptance rate generated a chain of conformations and a set of properties suitable for comparison with available experimental results. Comparison of calculated structures for glcNAc-Asn with those determined experimentally by NMR, circular dichroism spectroscopy, and X-ray crystallography showed that the Momany-Scheraga conformation energy (ECEPP) over-emphasized non-bonded repulsions. Based on the experimentally determined structures, an effective two-fold potential barrier was imposed on the anomeric linkage. Predictions based on conformational statistics were sensitive to the choice of a three-fold or two-fold torsional barrier at the anomeric linkage.
An interesting chloride ion effect in the Heck reaction

Abstract Addition of chloride ion is found to enhance the yields of cross-couplings between aryl iodides and selected olefin acceptors.
Detection of hepatocellular carcinoma in hepatitis C patients: Biomarker discovery by LC-MS

Hepatocellular carcinoma (HCC) accounts for most cases of liver cancer worldwide; contraction of hepatitis C (HCV) is considered a major risk factor for liver cancer even when individuals have not developed formal cirrhosis. Global, untargeted metabolic profiling methods were applied to serum samples from patients with either HCV alone or HCC (with underlying HCV). The main objective of the study was to identify metabolite based biomarkers associated with cancer risk, with the long term goal of ultimately improving early detection and prognosis. Serum global metabolite profiles from patients with HCC (n=37) and HCV (n=21) were obtained using high performance liquid chromatography-mass spectrometry (HPLC-MS) methods. The selection of statistically significant metabolites for partial least-squares discriminant analysis (PLS-DA) model creation based on biological and statistical significance was contrasted to that of a traditional approach utilizing p-values alone. A PLS-DA model created using the former approach resulted in a model with 92% sensitivity, 95% specificity, and an AUROC of 0.93. A series of PLS-DA models iteratively utilizing three to seven metabolites that were altered significantly (p<0.05) and sufficiently (FC≤0.7 or FC≥1.3) showed good performance using p-values alone; the best of these PLS-DA models was capable of generating 73% sensitivity, 95% specificity, and an AUROC of 0.92. Metabolic profiles derived from LC-MS readily distinguish patients with HCC and HCV from those with HCV only. Differences in the metabolic profiles between high-risk individuals and HCC indicate the possibility of identifying the early development of liver cancer in at risk patients. The use of biological significance as a selection process prior to PLS-DA modeling may offer improved probabilities for translation of newly discovered biomarkers to clinical application.
Current Status of the MiniBooNE Experiment

MiniBooNE is an experiment designed to refute or confirm the LSND oscillation result. MiniBooNE will look for oscillations of νμ → νe in a closed-box appearance analysis. MiniBooNE began collecting data in 2002, and is expected to continue data taking through 2005. Current MiniBooNE results are presented.
Contrast between Steady and Time-Averaged Unsteady Combustion Simulations

Time-averaged predictions from unsteady solutions of the two-dimensional Navier-Stokes equations are contrasted with Reynolds-averaged results for a reacting flow problem in a high pressure combustor. The goal is to determine whether the two-dimensional unsteady approximation can be useful as an engineering analysis in problems for which time-averaged quantities are of primary interest. The conditions are taken from an experiment in which non-premixed gaseous oxygen and hydrogen were injected into a combustion chamber through coaxial channels. The resulting flowfield is dominated by a large recirculation zone arising from the back-step created by the injector. The results of steady and time-averaged, unsteady solutions are strikingly different. The unsteady simulation produces strong unsteady structures whose time-averaged results lead to a much wider flame zone, a different recirculation zone structure, and a substantially different wall heat flux. The time-averaged calculations yield the correct combustor chamber pressure and compare considerably more favorably with heat flux measurements than do the RANS results. The two-dimensional approximation, however, overstates the unsteady vortex roll up and precludes large-scale mixing across the axis of symmetry, thereby giving deficient predictions near the centerline. Overall, the present results indicate that capturing large-scale unsteady characteristics can provide more accurate predictions of recirculation dominated reacting flows and suggest that two-dimensional, time-averaged solutions represent a potentially useful engineering tool for problems of this nature while also serving as a precursor for full three-dimensional simulations.
Simulation Reductions for the Ising Model

Abstract Polynomial time reductions between problems have long been used to delineate problem classes, where an oracle for solving one problem yields a solution to another. Simulation reductions also exist, where an oracle for simulation from a probability distribution is employed in order to obtain draws from another distribution. Here linear time simulation reductions are given for: The Ising spins world to the Ising subgraphs world and the Ising subgraphs world to the Ising spins world. This answers a long standing question of whether such a direct relationship between these two versions of the Ising model existed. Moreover, these reductions result in the first method for perfect simulation from the subgraphs world and a new Swendsen-Wang style Markov chain for the Ising model. The method used is to write the desired distribution with set parameters as a mixture of distributions where the parameters are at their extreme values.
Rapidity gaps and color evolution in QCD hard scattering

Abstract We discuss rapidity-gap events between two jets produced at high momentum transfer in ρ ρ scattering, from the point of view of the soft energy flow into the interjet region. We define a gap cross section and, in perturbative QCD (pQCD), resum all the leading logarithms in the soft intermediate energy. We show that the numerical result from our cross section reproduces the shape of the DO and CDF [1–3] experimental data.
Vortical flow control on a wing-body combination using tangential blowing

The objective of the experimental program reported here was to evaluate the possibility of using tangential blowing to create roll and yaw control on a delta wing-forebody combination at high angles of attack. It is found that the vortical flow over the model can be manipulated more efficiently by blowing on the nose section rather than fuselage. Large rolling moments and side forces are generated by blowing from forebody compared to wing blowing. For a wing-body combination, a model with a blunt nose is found to be less sensitive to flow asymmetry than a sharp-nosed configuration. Rolling moment changes sign from prestall to stall for all the configurations tested.
Spectral density and spectral distribution inference for long memory time series via fixed-b asymptotics

This paper studies taper-based estimates of the spectral density utilizing a fixed bandwidth ratio asymptotic framework, and makes several theoretical contributions: (i) we treat multiple frequencies jointly, (ii) we allow for long-range dependence or anti-persistence at differing frequencies, (iii) we allow for tapers that are only piecewise smooth or discontinuous, including flat-top and truncation tapers, (iv) we study higher-order accuracy through the limit distribution’s Laplace Transform, (v) we develop a taper-based estimation theory for the spectral distribution, and show how confidence bands can be constructed. Simulation results produce quantiles and document the finite-sample size properties of the estimators, and a few empirical applications demonstrate the utility of the new methods.
Methanesulfenyl triflate promoted iminosulfenylation of an allylic trichloroacetimidate. An efficient and stereospecific total synthesis of (+) mannostatin A

The stereospecific synthesis of glycoprotein processing enzyme inhibitor (+) mannostatin A 1 was achieved in ten steps from D-ribonolactone 9 (∼ 39% overall yield). The strategy featured methanesulfenyl triflate mediated intramolecular cyclization of allylic N-sufenylimidate 12.
Development of computer applications in emerging nations

The purpose of this paper is to explore a series of guidelines which will help identify attractive computer applications in emerging countries. We will examine areas of development from the standpoints of natural resources, labor intensive industries, public and private services. Then we shall explore levels of development in communications, education, high technology and the financial commitment of a nation. We shall examine the computer applications from a cost versus benefits viewpoint, and finally discuss a feasibility planning study.
The interest rate swap: Theory and evidence

Abstract Nonfinancial firms that use interest rate swaps are compared with nonusers for the years 1991, 1993, and 1995. Swap use grew from 6% of all firms in 1991 to 8% in 1995. Nonfinancial firms use fixed rate payer swaps more often than floating rate payer swaps. Firms that use swaps are significantly larger and have a higher debt to equity ratio relative to nonusers. Fixed rate payers receive a ratings' upgrade significantly more often than floating rate payers and experience a significantly higher percentage increase in net sales in the year of swap initiation relative to floating rate payers and the industry average. Floating rate payers have a significantly higher S&P bond rating relative to the industry average. The test results lend support to the information asymmetry theory of swap usage [Titman, S., 1992. Interest rate swaps and corporate financing choices, Journal of Finance 47, pp. 1503–1516] and lend some support to the asset substitution portion of the agency cost theory of swap usage [Wall, L.D., 1989. Interest rate swaps in an agency theoretic model with uncertain interest rates. Journal of Banking and Finance 13, pp. 261–270].
Thermal Expansion of Calcium Monoaluminate

The linear and the crystal-lattice thermal expansions of monoclinic CaO·Al2O3 were determined. The average coefficient α of linear thermal expansion between 22° and 1200°C is 7.7 × 10−6/°C. The crystal lattice expands anisotropically with expansion coefficients along the principal axes of the strain ellipsoid of 9.8, 7.3, and 5.9 × 10−6/°C for the same temperature interval.
High-fidelity simulations of unsteady flow through turbopumps and flowliners

High fidelity computations were carried out to analyze the orbiter LH2 feedline flowliner. Computations were performed on the Columbia platform which is a 10,240-processor supercluster consisting of 20 Altix nodes with 512 processors each. Various computational models were used to characterize the unsteady flow features in the turbopump, including the orbiter Low-Pressure-Fuel-Turbopump (LPFTP) inducer, the orbiter manifold and an experimental test article used to represent the manifold. Unsteady flow originating from the orbiter LPFTP inducer is one of the major contributors to the high frequency cyclic loading that results in high cycle fatigue damage to the gimbal flowliners just upstream of the LPFTP. The flow fields for the orbiter manifold and representative test article are computed and analyzed for similarities and differences. An incompressible Navier-Stokes flow solver INS3D, based on the artificial compressibility method, was used to compute the flow of liquid hydrogen in each test article.
On the leading coefficient of polynomials orthogonal over domains with corners

Let G be the interior domain of a piecewise analytic Jordan curve without cusps. Let {pn}n=0?$\{p_{n}\}_{n=0}^{\infty }$ be the sequence of polynomials that are orthonormal over G with respect to the area measure, with each pn having leading coefficient ?n>0. It has been proven in [9] that the asymptotic behavior of ?n as n??$n\to \infty $ is given by n+1??2n+2?n2=1??n,$$\frac{n+1}{\pi}\frac{\gamma^{2n+2}}{ {\lambda_{n}^{2}}}=1-\alpha_{n}, $$ where ?n=O(1/n) as n??$n\to \infty $ and ? is the reciprocal of the logarithmic capacity of the boundary ?G. In this paper, we prove that the O(1/n) estimate for the error term ?n is, in general, best possible, by exhibiting an example for which liminfn??n?n>0.$$\liminf_{n\to\infty}\,n\alpha_{n}>0. $$ The proof makes use of the Faber polynomials, about which a conjecture is formulated.
Quantum and classical tradeoffs

We initiate the study of quantifying the quantumness of a quantum circuit by the number of gates that do not preserve the computational basis, as a means to understand the nature of quantum algorithmic speedups. Intuitively, a reduction in the quantumness requires an increase in the amount of classical computation, thus giving a "quantum and classical tradeoff'.In this paper we present two results on this measure of quantumness. The first gives almost matching upper and lower bounds on the question: "what is the minimum number of non-basis-preserving gates required to generate a good approximation to a given state". This question is the quantum analogy of the following classical question, "how many fair coins are needed to generate a given probability distribution", which was studied and resolved by Knuth and Yao in 1976 [Algorithms and Complexity: New Directions and Recent Results, Academic Press, New York, 1976, pp. 357-428]. Our second result shows that any quantum algorithm that solves Grover's Problem of size n using k queries and l levels of non-basis-preserving gates must have kl = Ω(n).
A highly active palladium catalyst for intermolecular hydroamination. Factors that control reactivity and additions of functionalized anilines to dienes and vinylarenes.

We report a catalyst for intermolecular hydroamination of vinylarenes that is substantially more active for this process than catalysts published previously. With this more reactive catalyst, we demonstrate that additions of amines to vinylarenes and dienes occur in the presence of potentially reactive functional groups, such as ketones with enolizable hydrogens, free alcohols, free carboxylic acids, free amides, nitriles, and esters. The catalyst for these reactions is generated from [Pd(η3-allyl)Cl]2 (with or without added AgOTf) or [Pd(CH3CN)4](BF4)2 and Xantphos (9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene), which generates complexes with large P−Pd−P bite angles. Studies on the rate of the C−N bond-forming step that occurs by attack of amine on an η3-phenethyl and an η3-allyl complex were conducted to determine the effect of the bite angle on the rate of this nucleophilic attack. Studies on model η3-benzyl complexes containing various bisphosphines showed that the nucleophilic attack was faster f...
Extraordinary Responsive Intermetallic Compounds: the R5T4 Family (R = Rare Earth, T = Group 13–15 Element)

The R5T4 intermetallic compounds of rare earth elements (R) with the group 14 elements (T) adopt a number of layered crystal structures that reversibly transform into each other. The transformations proceed through massive shear displacements of their main structural units, i.e. slabs, which are pseudo two dimensional blocks of atoms stacked along a certain crystallographic direction. These transformations can be triggered by change in chemical composition of the compounds (including partial substitutions of the group 14 elements by the group 13 or 15 elements), temperature, applied pressure, or applied magnetic field. The physical properties of these compounds are usually intimately related to their crystallography, and especially the concomitant magnetic and crystallographic transitions. As a result, strong magnetocaloric, magnetostrictive, magnetoresistance, and other effects are commonly observed. Consequently, a large change of the materials' properties can be achieved by a relatively weak change of external thermodynamic conditions.
The future of economics: the appropriately educated in pursuit of the knowable

Thispaper arguesthat,currently,significant changeistakingplaceineconomics because (1) technological changes in analytic and computing methods are opening up new avenues of study, and (2) the ‘low hanging fruit’ from previous approaches and methods have already been picked. It offers a vision of the future of economics that sees economists focusing less on the study of infinitely bright agents operating in information rich environments and more on the study of reasonably bright individuals operating in information-poor environments. Agent-based models and computer analysis of data will increase in importance, and deductive analytics will decrease in importance.
Benzylic oxidation by the gifIV system

Oxidation of ethylbenzene, diphenylmethane and benzylcyclopropane affords, in each case, the corresponding ketone as unique product. There is no detectable attack on the aromatic rings and only traces of phenol are formed from benzene. The oxidation of cumene affords acetophenone and 2-phenyl-2-hydroxypropane in nearly the same proportions as in a GifIV oxidation of cumene hydroperoxide. An explanation is given.
Online weighted matching

Abstract We introduce and study online versions of weighted matching problems in metric spaces. We present a simple 2 k − 1 competitive algorithm for online minimum weighted bipartite matching where 2 k is the number of nodes. We show that this competitiveness is optimal. For online maximum matching, we prove that the greedy algorithm achieves an optimal competitive factor of 3. In contrast, we prove that the greedy algorithm performs exponentially poorly for online minimum matching.
An Iterative Procedure for Nonlinear Flutter Analysis

An iterative procedure in the frequency domain is presented for flutter analysis of large dynamic systems with multiple structural nonlinearities. The major components of the procedure are the describing function approach for system linearization, a structural dynamics modification method for shifting system mode shapes and frequencies, and a complex eigenvalue algorithm for solution of the flutter equation. The purpose of the procedure is to achieve alignment of the oscillatory amplitude in each nonlinear spring with the describing function prediction of stiffness before computing the final stability characteristics. The result is a system tuned to the flutter frequency at the time of instability. To support the development and validation of the procedure, several describing functions are formulated and a quantitative measure of the errors in each is presented. Validation of the iterative method is accomplished through examples involving dynamic systems of increasing complexity, coupled with various representations of the unsteady aerodynamic forces. Both numerical simulations and experimental data are used to compare with the iterative predictions. In the cases studied, the agreement is good to excellent, with the method accurately predicting the amplitude of a limit cycle flutter as well as the initial disturbance required to produce flutter.
Ten rules for writing readably

A readable style is created by proper handling of ideas, words, phrases, clauses, logic, syntax, and personality. Every word should be written for somebody. These rules tell how to create readable writing: (1) Read some great writing every day; (2) use genuinely familiar words; (3) break sentences into clearly defined units; (4) use signals in sentences (because, so, but); (5) make the subjects and verbs absolutely clear; (6) balance sentences with parallel structures; (7) use nouns sparingly, especially as modifiers; (8) make sentences answer Who does what?; (9) surprise the reader with variety; and (10) do not hesitate to break a rule or create a new one.
Management of supraglottic dysgenesis presenting as laryngomalacia.

Abstract Laryngomalacia is a common source of stridor and can lead to significant upper airway obstruction and feeding disturbances in infants. We describe a unique case of supraglottic dysgenesis presenting as laryngomalacia featuring a prominent “s-shaped” epiglottis with both posterior edges fused to the right aryepiglottic fold/arytenoid complex. Although this anomaly is not accounted for in any of the current laryngomalacia classification schemes, modified laser supraglottoplasty was a satisfactory approach leading to successful decannulation. Laryngeal embryology and possible timing of the pathogenesis of this rare occurrence are reviewed as well.
STAS: a code suite for space-time adaptive processing of IR images

This presentation describes STAS (space-time analysis stream), a suite of advanced signal processing codes for the detection of dim targets in 'look-down' IR clutter. STAS has been tested on several hundred thousand IR clutter scenes in the NAWC SkyBall Data Base, and has been shown to be very robust. Code modules in the STAS detection stream perform the following functions: (1) calibration, bad-pixel identification and editing; (2) image registration, clutter estimation and clutter subtraction; (3) velocity stacking and matched-filtering. Other code modules in STAS allow synthesis and rework of IR images, to emulate data from arbitrary IR sensors, with arbitrary trajectories over the clutter scene. THe theory and performance of various STAS modules will be described, with emphasis on registration method, fast methods for mapping from the focal plane to the ground, treatment of bad pixels, digital interpolator design/implementation, and matched filter design. Examples of processed IR images will be displayed.
An asymptotically least-favorable Chernoff bound for a large class of dependent data processes

It is desired to determine the worst-case asymptotic error probability performance of a given detector operating in an environment of uncertain data dependency. A class of Markov data process distributions is considered which satisfy a one-shift dependency bound and agree with a specified univariate distribution. Within this dependency contamination class the distribution structure which minimizes the exponential rate of decrease of detection error probabilities is identified. This is a uniform least-favorability principle, because the least-favorable dependency structure is the same for all bounded memoryless detectors. The error probability exponential rate criterion used is a device of large deviations theory. The results agree well with previous results obtained using Pitman's asymptotic relative efficiency (ARE), which is a more tractable small-signal performance criterion. In contrast to ARE, large deviations theory is closely related to finite-sample error probabilities via the finite-sample Chernoff bounds and other exponentially tight bounds and other approximations.
An efficient algorithm for constructing optimal design of computer experiments

The long computational time required in constructing optimal designs for computer experiments has limited their uses in practice. In this paper, a new algorithm for constructing optimal experimental designs is developed. There are two major developments involved in this work. One is on developing an efficient global optimal search algorithm, named as enhanced stochastic evolutionary (ESE) algorithm. The other is on developing efficient methods for evaluating optimality criteria. The proposed algorithm is compared to existing techniques and found to be much more efficient in terms of the computation time, the number of exchanges needed for generating new designs, and the achieved optimality criteria. The algorithm is also very flexible to construct various classes of optimal designs to retain certain desired structural properties.
RR flux on Calabi–Yau and partial supersymmetry breaking

Abstract We show how turning on Flux for RR (and NS-NS) field strengths on non-compact Calabi–Yau 3-folds can serve as a way to partially break supersymmetry from N=2 to N=1 by mass deformation. The freezing of the moduli of Calabi–Yau in the presence of the flux is the familiar phenomenon of freezing of fields in supersymmetric theories upon mass deformations.
Challenges and opportunities in academic hospital medicine: report from the Academic Hospital Medicine Summit.

BACKGROUND: The field of hospital medicine is growing rapidly in academic medical centers. However, few organizations have explicitly considered the opportunities for and barriers to hospital medicine's development as an academic field in internal medicine. OBJECTIVE: The objective was to develop consensus around key areas limiting or facilitating hospital medicine's development as an academic discipline. DESIGN: The design was a consensus format conference of key stakeholders in academic hospital medicine. RESULTS: The consensus group identified several issues impeding the development of academic hospital medicine as a recognized entity in academic settings, including extraordinarily rapid growth, increasingly preponderant nonteaching roles, and demands to perform nonclinical duties (such as quality improvement) not generally viewed as academic pursuits. The consensus group developed recommendations for addressing these concerns, specifically: 1) characterizing the optimal job description for an academic hospitalist, 2) developing better local and at-a-distance opportunities for training academic hospitalists in key aspects of early career success, and 3) advocating for the development of fellows and junior faculty researchers in hospital medicine. SUMMARY: Fostering academic hospital medicine will help address these issues more effectively and will help the field while also attracting the next generation of generalists needed to care for an increasingly complex inpatient population. Journal of Hospital Medicine 2009;4:240–246. © 2009 Society of Hospital Medicine.
String statistical mechanics

Abstract A review of the statistical mechanics of free string networks is given. This provides an interesting example of a system with canonical thermodynamics and in particular the notion of temperature break down. The results are applied to cosmic strings where they show good agreement with numerical results. They may also have important implications for the behaviour of fundamental strings at high density. Various erroneous recent claims regarding the statistical mechanics of fundamental strings are also discussed, in particular regarding duality, the role of winding modes, and the notion of negative specific heats.
American heart association guidelines for primary prevention of atherosclerotic cardiovascular disease beginning in childhood

Atherosclerotic cardiovascular disease remains the leading cause of both death and disability in North America. Evidence that most cardiovascular disease is preventable led to development of the American Heart Association’s initial “Guide to the Primary Prevention of Cardiovascular Disease” in 1996 and the updated version in 2002. Those guidelines do not address prevention in children, a group for whom primary prevention should hold the most promise. Emergence of multiple lines of evidence with regard to the importance of known risk factors for atherosclerotic disease in children and young adults has provided the impetus to develop guidelines for primary prevention in this young population. Pathological studies have shown that both the presence and extent of atherosclerotic lesions at autopsy after unexpected death of children and young adults correlate positively and significantly with established risk factors, namely low-density lipoprotein cholesterol, triglycerides, systolic and diastolic blood pressure, body mass index, and presence of cigarette smoking. Findings from the Bogalusa study indicate that as the number of cardiovascular risk factors increases, so does the pathological evidence for atherosclerosis in the aorta and coronary arteries beginning in early childhood. Electron beam computed tomography of coronary artery calcium and increased carotid artery intima-media thickness, an ultrasound measure of carotid artery atherosclerosis, have been evaluated in 29- to 39-year-olds monitored from 4 years of age. Significant risk predictors for coronary artery calcium were obesity and elevated blood pressure in childhood and increased body mass index and dyslipidemia as young adults. Multiple epidemiological studies have demonstrated a disturbing increase in the prevalence of obesity beginning in childhood, with at least 22% of 6- to 17-year-olds diagnosed as overweight. This is a cause for particular concern because of the strong association between obesity and hypertension, dyslipidemia, and type II diabetes mellitus beginning in childhood. Long-term follow-up studies have demonstrated …
Anomalous coherent backscattering of light from opal photonic crystals

We studied coherent backscattering (CBS) of light from opal photonic crystals with incomplete band gaps. We observed a dramatic broadening of the CBS cone for incident angles close to the Bragg condition in the crystals. We modify the conventional CBS theory to incorporate Bragg attenuation resulting from the photonic band structure. By fitting the CBS data with the modified theory, we extract both the disorder-induced light mean-free path and the Bragg attenuation length of the inherent opal photonic crystal.