cssi/SciSciGPT-SciSciNet huggingface dataset:
Computational Study of Stall Flutter in Linear Cascades

Aeroelastic interaction in turbomachinery is of prime interest to operators, designers, and aeroelasticans. Operation at off-design conditions may promote blade stall; eventually the stall pattern will propagate around the blade annulus. The unsteady periodic nature of propagating stall will force blade vibration and blade flutter may occur if the stall propagation frequency is entrained by the blade natural frequency. In this work a computational scheme based on the vortex method is used to simulate the flow over a linear cascade of airfoils. The viscous effect is confined to a thin layer, which determines the separation points on the airfoil surfaces. The preliminary structural model is a two-dimensional characteristic section with a single degree of freedom in either bending or torsion. A study of the relationship between the stall propagation frequency and the blade natural frequency has been conducted. The study shows that entrainment, or frequency synchronization, occurs, resulting in pure torsional flutter over a certain interval of reduced frequency. A severe blade torsional amplitude (of order 20 deg) has been computed in the entrainment region, reaching its largest value in the center of the interval. However, in practice, compressor blades will not sustain this vibration and blade failure may occurmore » before reaching such a large amplitude. Outside the entrainment interval the stall propagation is shown to be independent of the blade natural frequency. In addition, computational results show that there is no entrainment in the pure bending mode. Rather, de-entrainment occurs with similar flow conditions and similar stall frequencies, resulting in blade buffeting in pure bending.« less
Elastoviscous Properties of Amorphous Polymers in the Transition Region. I

Abstract Experimental data on the stress-relaxation modulus Er,T(t) of a GR-S gum vulcanizate at a series of temperatures in the transition region are presented, and a “master curve” of log Q(t/K) vs. log (t/K) is thereby constructed. The characteristic relaxation time, K, for each temperature is defined and tabulated. A distinctive temperature, Td, is observed at which the activation energy for K is a maximum. Analytical expressions are given which describe the GR-S master-curve with great accuracy. The same analytical procedure can be successfully applied to data previously obtained for polymethyl methacrylate. A reduced equation is proposed which describes the time and temperature dependence of Q(t/K) in the transition region for both polymers.
Risk stratification for survival and leukemic transformation in essential thrombocythemia: a single institutional study of 605 patients.

Unlike the case with thrombosis, prognostic models for survival and leukemic transformation (LT) in essential thrombocythemia (ET) are not available. Among 605 patients with ET seen at our institution and followed for a median of 84 months, 155 died and LT was documented in 20 patients (3.3%). In a multivariable analysis, hemoglobin level below normal (females or =60 years, leukocyte count> or =15 x 10(9)/l, smoking, diabetes mellitus and thrombosis. For LT, platelet count> or =1000 x 10(9)/l but not cytoreductive therapy was flagged as an additional independent risk factor. In fact, four of the 20 patients (20%) with LT were untreated previously. We used the above information to construct prognostic models that effectively discriminated among low-, intermediate- and high-risk groups with respective median survivals of 278, 200 and 111 months (P<0.0001), and LT rates of 0.4, 4.8 and 6.5% (P=0.0009) respectively. Presence of JAK2V617F did not impact either survival or LT and mutational frequency was similar among the different risk groups.
Theory of two-photon Lamb dips

A semiclassical theory of two-photon Lamb dips is presented, when one of the radiations is in the radio-frequency region and the other is in the optical region. Perturbation solutions as well as an exact recurrence formula are discussed. For the latter case numerical results are given. The resonance line shape of the two-photon Lamb dip shows a variety of changes according to the experimental conditions. When both the optical and the rf fields are weak a line is of a dispersion form. When the rf field is increased, the line changes to a Lorentzian form. When the optical field is increased, the line is shifted and broadened. If the radio frequency is close to or less than the Doppler width of the gas, a two-photon Lamb dip is accompanied with satellite dips which correspond to molecules with nonzero velocity components along the propagation of the laser radiation. The intensity of a two-photon Lamb dip is expected to decrease rapidly with increasing radio frequency. Additional effects when the sample cell is placed inside the laser cavity are also discussed. Those results agree qualitatively with recent observations by Fruend, R\"omheld, and Oka.
Plasticity and diffusion creep of dolomite

Abstract Natural and synthetic dolomites have been shortened in triaxial compression experiments at temperatures of 400–850 °C, equilibrium CO2 pore pressures, effective confining pressures of 50–400 MPa, and strain rates of 10− 4 to 10− 7 s− 1. At low temperatures (T 600 MPa), both for coarse-grained (240 μm) and fine-grained (2 μm and 12 μm) samples; differential stresses vary little with strain rate or temperature and microstructures of coarse-grained samples are dominated by f-twins and undulatory extinction. An exponential relation (ɛ˙ = ɛ˙o exp[α(σ1 − σ3)] between strain rate ɛ˙ and differential stress (σ1 − σ3) describes the crystal plasticity of dolomite at a fixed Pe and T, with α = 0.079 (± 0.01) MPa− 1 and 0.023 (± 07.03) MPa− 1 for coarse- and fine-grained materials, respectively. However, measured values of (σ1 − σ3) increase with increasing temperature, a trend that has been observed for dolomite single crystals but cannot be described by an Arrhenius relation. At high temperatures (T ≥ 800 °C for coarse, T ≥ 700 °C for fine), dolomite strengths are reduced with increasing temperature and decreasing strain rate, but the mechanisms of deformation differ depending on grain size. High temperature flow strengths of coarse-grained dolomite can be described by a power law ɛ˙ = ɛ˙o[(σ1 − σ3) / μ]nexp(− H⁎ / RT) with a large value of n (> 5) and a ratio of parameters H⁎ / n = 60 (± 6) kJ/mol. Microstructures of coarse-grained samples deformed at T ≥ 800 °C show evidence of dislocation creep with little mechanical twinning. High temperature flow strengths of fine-grained synthetic dolomite fit a thermally activated Newtonian law, where the effective n = 1.28 (± 0.15) and H⁎ = 280 (± 45 kJ/mol), consistent with diffusion creep. The change in mechanical response of coarse-grained natural dolomite with increasing temperature represents a transition from twinning and slip with little or no recovery to dislocation creep, while the change in response of fine-grained synthetic dolomite represents a transition from crystal plasticity to diffusion creep. The combined results for coarse- and fine-grained dolomites define a deformation mechanism map with fields of crystal plasticity, dislocation creep, and diffusion creep. Strengths of coarse-grained dolomite in the crystal plastic and dislocation creep fields are much larger than strengths of calcite rocks deformed by similar mechanisms. In contrast, strengths of fine-grained dolomite deformed by diffusion creep are more comparable to those of fine-grained calcite, suggesting little contrast in rheology.
Sulfur oxygenation in biomimetic non-heme iron-thiolate complexes.

The S-oxygenation of cysteine with dioxygen to give cysteine sulfinic acid occurs at the non-heme iron active site of cysteine dioxygenase. Similar S-oxygenation events occur in other non-heme iron enzymes, including nitrile hydratase and isopenicillin N synthase, and these enzymes have inspired the development of a class of [NxSy]–Fe model complexes. Certain members of this class have provided some intriguing examples of S-oxygenation, and this article summarizes these results, focusing on the non-heme iron(II/III)–thiolate model complexes that are known to react with O2 or other O-atom transfer oxidants to yield sulfur oxygenates. Key aspects of the synthesis, structure, and reactivity of these systems are presented, along with any mechanistic information available on the oxygenation reactions. A number of iron(III)–thiolate complexes react with O2 to give S-oxygenates, and the degree to which the thiolate sulfur donors are oxidized varies among the different complexes, depending upon the nature of the ligand, metal geometry, and spin state. The first examples of iron(II)–thiolate complexes that react with O2 to give selective S-oxygenation are just emerging. Mechanistic information on these transformations is limited, with isotope labeling studies providing much of the current mechanistic data. The many questions that remain unanswered for both models and enzymes provide strong motivation for future work in this area.
Fixity and free group actions on products of spheres

A representation G ⊂ U(n) of degree n has fixity equal to the smallest integer f such that the induced action of G on U(n) /U(n-f-1) is free. Using bundle theory we show that if G admits a representation of fixity one, then it acts freely and smoothly on \(\mathbb S^{2n-1}\times\mathbb S^{4n-5}.\) We use this to prove that a finite p-group (for p > 3) acts freely and smoothly on a product of two spheres if and only if it does not contain (ℤ /p)3 as a subgroup.
A four-year comparison between the utilization and use-effectiveness of sequential and combined oral contraceptives

Abstract A comparison of the utilization and effectiveness of the pill between comparable groups of women on sequential and combined doses was based on data gathered for 2,000 women from the Buffalo Planned Parenthood Center. The type of pill prescribed for women in this study was randomly selected. Synthetic cohort life tables, following procedures developed by Tietze, were compiled for women using each type of pill. The finding indicate that combined oral contraceptives are superior to sequentials. Not only was the rate of accidental pregnancy less than half as great for combined users, but the continuation rate was 14 percent higher for women on combined pills. In addition, significantly fewer women on combined pills terminated for medical reasons. These findings, combined with data from Sartwell, et al. , which indicated that women on sequential pills are at higher risk to thromboembolism, provide persuasive evidence to limit the use of sequential contraceptives.
Second hand smoke, age of exposure and lung cancer risk.

Summary Background Exposure to second hand smoke (SHS) has been identified as a risk factor for lung cancer for three decades. It is also known that the lung continues to grow from birth to adulthood, when lung growth stops. We hypothesize that after adjusting for active cigarette smoking, if SHS exposure took place during the period of growth, i.e. in the earlier part of life (0–25 years of age) the risk of lung cancer is greater compared to an exposure occurring after age 25. Method Second hand smoke exposure was self-reported for three different activities (leisure, work and at home) for this study population of 1669 cases and 1263 controls. We created variables that captured location of exposure and timing of first exposure with respect to a study participant's age (0–25, >25 years of age). Multiple logistic regressions were used to study the association between SHS exposure and lung cancer, adjusting for age, gender and active smoking variables. Result For study participants that were exposed to SHS at both activities (work and leisure) and compared to one or no activity, the adjusted odds ratio (AOR) for lung cancer was 1.30 (1.08–1.57) when exposure occurred between birth and age 25 and 0.66 (0.21–1.57) if exposure occurred after age 25 years. Respective results for non-smokers were 1.29 (0.82–2.02) and 0.87 (0.22–3.38), and current and ex-smokers combined 1.28 (1.04–1.58) and 0.66 (0.15–2.85). Conclusion All individuals exposed to SHS have a higher risk of lung cancer. Furthermore, this study suggests that subjects first exposed before age 25 have a higher lung cancer risk compared to those for whom first exposure occurred after age 25 years.
Synthesis of substituted malonic acids from carbon radicals generated from carboxylic acids

Abstract The reaction of various olefins with carbon radicals generated by photolysis of Barton-esters finishes adducts suitable for transformation into the corresponding malonic acids.
Expectations, learning, and the changing relationship between oil prices and the macroeconomy☆

This paper estimates a structural general equilibrium model to investigate the changing relationship between the oil price and macroeconomic variables. The oil price, through the role of oil in production and consumption, affects aggregate demand and supply in the model. The assumption of rational expectations is relaxed in favor of learning. Oil prices, therefore, affect the economy through an additional channel, i.e. through their effect on the formation of agents' beliefs. The estimated learning dynamics indicates that economic agents' perceptions about the effects of oil prices on the economy have changed over time: oil prices were perceived to have large effects on output and inflation in the 1970s, but only milder effects after the mid-1980s. Since expectations play a large role in the determination of output and inflation, the effects of oil price increases on expectations can magnify the response of macroeconomic variables to oil price shocks. In the estimated model, in fact, the implied responses of output and inflation to oil price shocks were much more pronounced in the 1970s than in 2008. Therefore, through the time variation in the impact of oil prices on beliefs, the paper can successfully explain the observed weakening of the effects of oil price shocks on real activity and inflation.
A Brief review of 'little string theories'

This is a brief review of the current state of knowledge on `little string theories', which are non-gravitational theories having several string-like properties. We focus on the six-dimensional maximally supersymmetric `little string theories' and describe their definition, some of their simple properties, the motivations for studying them, the discrete lightcone quantization and holographic constructions of these theories and their behaviour at finite energy density.
Emission Spectra from Internal Shocks in Gamma-Ray Burst Sources

Unsteady activity of γ-ray burst sources leads to internal shocks in their emergent relativistic wind. We study the emission spectra from such shocks, assuming that they produce a power-law distribution of relativistic electrons and possess strong magnetic fields. The synchrotron radiation emitted by the accelerated electrons is Compton upscattered multiple times by the same electrons. A substantial fraction of the scattered photons acquire high energies and produce e -->+e -->− pairs. The pairs transfer back their kinetic energy to the radiation through Compton scattering. The generic spectral signature from pair creation and multiple Compton scattering is highly sensitive to the radius at which the shock dissipation takes place and to the Lorentz factor of the wind. The entire emission spectrum extends over a wide range of photon energies, from the optical regime up to TeV energies. For reasonable values of the wind parameters, the calculated spectrum is found to be in good qualitative agreement with the observed burst spectra.
Connections on the state-space over conformal field theories

Abstract Motivated by the problem of background independence of closed string field theory we study geometry on the infinite vector bundle of local fields over the space of conformal field theories (CFTs). With any connection we can associate an excluded domain D for the integral of marginal operators, and an operator one-form ωμ. The pair (D, ωμ) determines the covariant derivative of any correlator of local fields. We obtain interesting classes of connections in which ωμ's can be written in terms of CFT data. For these connections we compute their curvatures in terms of four-point correlators, D, and ωμ. Among these connections three are of particular interest. A flat, metric compatible connection Γ , and connections c and c with non-vanishing curvature, with the latter metric compatible. The flat connection cannot be used to do parallel transport over a finite distance. Parallel transport with either c or c , however, allows us to construct a CFT in the state-space of another CFT a finite distance away. The construction is given in the form of perturbation theory manifestly free of divergences.
Banks and Payday Lenders: Friends or Foes?

This paper investigates the geographic distribution of payday lenders and banks that operate throughout the United States. State-level data are used to indicate differences in the regulatory environment across the states. Given the different constrains on interest rates and other aspects of the payday loan products, we empirically examine the relationship between the number of payday lender stores and various demographic and economic characteristics. Our results indicate that number of stores is positively related to the percentage of African American population, the percentage of population that is aged 15 and under and the poverty rate. The number of stores is also negatively related to income per capita and educational levels.
Principles of Economics Without the Prince of Denmark

In most introductory textbooks on principles of economics, discussion of the theory or practice of entrepreneurship is almost entirely absent. This omission is striking, given the important role in economic growth that economists assign to the entrepreneur. While there are plausible explanations for this omission, new research suggests the beginnings of a body of formal microtheory on innovative entrepreneurship. In this article, the authors first review treatment of the entrepreneur in the latest editions of three commonly used introductory economics textbooks, each of which includes a substantive discussion of entrepreneurship. Second, the authors present brief overviews of new microtheories of entrepreneurship (Parker 2009; Spulber 2009; and Baumol 2010), each of which has potential to serve as inspiration and to provide a framework for inclusion of entrepreneurship in introductory microtheory.
Sampling and recovery of multidimensional bandlimited functions via frames

Abstract In this paper, we investigate frames for L 2 [ − π , π ] d consisting of exponential functions in connection to oversampling and nonuniform sampling of bandlimited functions. We derive a multidimensional nonuniform oversampling formula for bandlimited functions with a fairly general frequency domain. The stability of said formula under various perturbations in the sampled data is investigated, and a computationally manageable simplification of the main oversampling theorem is given. Also, a generalization of Kadec's 1/4 theorem to higher dimensions is considered. Finally, the developed techniques are used to approximate biorthogonal functions of particular exponential Riesz bases for L 2 [ − π , π ] , and a well-known theorem of Levinson is recovered as a corollary.
Practical Results with CADSYS

CADSYS is an interactive computer-aided decision support system which interfaces a designer with a mathematical, rather than graphic, model of a design problem. Multiple design goals can be imposed in the form of equality and inequality constraints, whose levels can be manipulated. A numerical search is used to find designs which meet the constraints. CADSYS has now been applied to two real and current design problems: the hydraulic system of a novel inertial navigation unit and the financial, technical, and logistical problem of liquified natural gas tanker design and operation. Both of these studies returned new understanding of the problems themselves and of the capabilities of CADSYS.
Effects of large field cutoffs in scalar and gauge models

We discuss the notion of a large field cutoff for LGT with compact groups. We propose and compare gauge invariant and gauge dependent (in the Landau gauge) criteria to sort the configurations into “large-field” and “small-field” configurations. We show that the correlations between volume average of field size indicators and the behavior of the tail of the distribution are very different in the gauge and scalar cases. We show that the effect of discarding the large field configurations on the plaquette average is very different above, below and near β = 5.6 for a pure SU(3) LGT.
Estriol conjugates in body fluids in late human pregnancy.

Abstract A new method was developed for the assay of estriol (E 3 ) conjugates in amniotic fluid, urine and plasma of third trimester human pregnancy. Tritiated estriol-3-sulfate (E 3 -3S), estriol-16-glucosiduronate (E 3 -16G) estriol-3-glucosiduronate (E 3 -3G) and estriol-3-sulfate-16-glucosiduronate (E 3 -3S-16G) are added to the fluid. The conjugates are separated as their triethylammonium salts on Sephadex LH-20. Each conjugate is hydrolyzed enzymatically and the estriol is purified by solvent extractions. The estriol is quantitated by radioimmunoassay. In the amniotic fluid E 3 -16G and E 3 -3S-16G comprised about 75% of the total E 3 conjugates. In normal pregnancy the E 3 -16G/E 3 -3S-16G ratio increased markedly with gestational age. In Rh-isoimmunization disease the ratio increased less dramatically and the patterns were erratic. In the urine E 3 -16G predominated (70–80%) whereas in the plasma E 3 -3S-16G comprised about 45% and E 3 -16G about 25% of the total. The concentrations of E 3 -3S and E 3 -16G were variable. The renal clearances in ml/min of the E 3 conjugates measured in 2 subjects are as follows: E 3 -16G, 343–508 (similar to that of p-aminohippuric acid); E 3 -3G, 64—149; E 3 -3S, 13–34; and E 3 -3S-16G, 21—29. These methods appear applicable to the study of a variety of conditions in pregnancy in which pathology may be reflected in abnormal profiles of E 3 conjugates.
Are simple tests of son preference useful? An evaluation using data from Vietnam

Son preference is widespread although not universal. Where it occurs it may lead to higher fertility rates. Ideally son preference should be measured in the context of a hazards or parity progression model of fertility, or a logistic model of contraceptive use. Such models require large amounts of survey data, particularly to measure the covariates. Can son preference be discerned reliably using tests which rely on more limited information? The answer is yes, based on applying eight simple tests to data from the Vietnam Living Standards Survey of 1992–93 and comparing the outcomes with the benchmark results from fuller models. Some, but not all, of the simpler tests accurately measure son preference, including estimating a simple hazards or progression parity model, the unisex sibship test, and the sibling differentials test.
An alternative scenario for non-abelian quantum hair

Abstract Topologically charged black holes in the theory with a 2-form coupled to a non-abelian gauge field are investigated. It is found that the ground states of black holes are classified by a coset space O (N 2 −1) SU (N) when the gauge group is SU(N).
Heavy quark fragmentation to polarised quarkonium

Abstract We calculate the polarisation of Ψ's and γ's produced by the fragmentation to transversely aligned quarkonium is slightly enhanced relative to longitudinally polarised quarkonium. This net alignment corresponds to a ∼ 5% asymmetry in the angular distribution of leptons produced in the subsequent decay of the quarkonium. We point out that the leading gluon contribution to Ψ and γ production arises from the evolution of the charm quark fragmentation function, rather than from direct gluon fragmentation.
Magellan radio occultation measurements of atmospheric waves on Venus

Radio occultation experiments were conducted at Venus on three consecutive orbits of the Magellan spacecraft in October 1991. Each occultation occurred over the same topography (67 deg N, 127 deg E) and at the same local time (22 hr 5 min), but the data are sensitive to zonal variations because the atmosphere rotates significantly during one orbit. Through comparisons between observations and predictions of standard wave theory, we have demonstrated that small-scale oscillations in retrieved temperature profiles as well as scintillations in received signal intensity are caused by a spectrum of vertically propagating internal gravity waves. There is a strong similarity between the intensity scintillations observed here and previous measurements, which pertain to a wide range of locations and experiment dates. This implies that the same basic phenomenon underlies all the observations and hence that gravity waves are a persistent, global feature of Venus' atmosphere. We obtained a fairly complete characterization of a gravity wave that appears above the middle cloud in temperature measurements on all three orbits. The amplitude and vertical wavelength are about 4 K and 2.5 km respectively, at 65 km. A model for radiative damping implies that the wave intrinsic frequency is approximately 2 x 10(exp 4) rad/sec, the corresponding ratio between horizontal and vertical wavelengths is approximately 100. The wave is nearly stationary relative to the surface or the Sun. Radiative attenuation limits the wave amplitude at altitudes above approximately 65 km, leading to wave drag on the mean zonal winds of about +0.4 m/sec per day (eastward). The sign, magnitude, and location of this forcing suggest a possible role in explaining the decrease with height in the zonal wind speed that is believed to occur above the cloud tops. Temperature oscillations with larger vertical wavelengths (5-10 km) were also observed on all three orbits, but we are able unable to interpret these unambiguously.
A numerical resolution study of high order essentially non-oscillatory schemes applied to incompressible flow

High order essentially non-oscillatory (ENO) schemes, originally designed for compressible flow and in general for hyperbolic conservation laws, are applied to incompressible Euler and Navier-Stokes equations with periodic boundary conditions. The projection to divergence-free velocity fields is achieved by fourth-order central differences through fast Fourier transforms (FFT) and a mild high-order filtering. The objective of this work is to assess the resolution of ENO schemes for large scale features of the flow when a coarse grid is used and small scale features of the flow, such as shears and roll-ups, are not fully resolved. It is found that high-order ENO schemes remain stable under such situations and quantities related to large scale features, such as the total circulation around the roll-up region, are adequately resolved.
Proposal for a simple model of dynamical SUSY breaking

Abstract We discuss supersymmetric SU (2) gauge theory with a single matter field in the I = 3 2 representation. This theory has a moduli space of exactly degenerate vacua. Classically it is the complex plane with an orbifold singularity at the origin. There seem to be two possible candidates for the quantum theory at the origin. In both the global chiral symmetry is unbroken. The first is interacting quarks and gluons at a non-trivial infrared fixed point — a non-Abelian Coulomb phase. The second, which we consider more likely, is a confining phase where the singularity is simply smoothed out. If this second, more likely, possibility is realized, supersymmetry will dynamically break when a tree level superpotential is added. This would be the simplest known gauge theory which dynamically breaks supersymmetry.
Comparing Teacher Education and Finance Majors' Agreement with Financial Morality Topics.

This article describes findings from a research survey that measured agreement with items that concerned financial morality. The authors analyzed the responses of 382 teacher education majors and finance majors at a Midwestern institution of higher learning in the USA. The study found highest agreement with items measuring business responsibilities, and lowest agreement with items related to wealth distribution. It noted significant differences and varying effect sizes among education and finance majors' interpretation of items concerning business responsibility and wealth distribution. The authors recommend additional research to interpret the concept of financial morality and provide suggestions for related study. Financial literacy represents a topic of interest to the social studies education community, however, recent literature (e.g. Arthur, 2012; Lucey, 2012; Pinto, 2012) suggests that existent approaches to financial literacy education lack moral impetus and reinforce antidemocratic principles. If financial literacy contains moral elements, then one's social perspective may relate to his or her interpretation of them. Among college students, this view may relate to the patterns of thinking espoused within their professional preparations. In a twenty-first century climate of diminishing global resources and increasing capitalist tendencies, how young adults interpret their financial 'moralness' greatly relates to the human outcomes associated with long-term acquisition and distribution of goods and services. Interpreting patterns of agreement with elements of financial morality and how they may differ among college-aged young adults may prompt dialogues about the influences on agreement patterns with appropriate education responses to the concept. This article offers a conceptualization of financial morality, describing the results of a related research study, and providing direction for future moral education and research. It provides a basis for scholarly dialogue about reconceptualizing financial morality and its ties to social education.
Dimensions, nodes and phases in quantum numbers

Students of quantum mechanics encounter discrete quantum numbers in a somewhat incoherent and bewildering number of ways. For each physical system studied, quantum numbers seem to be introduced in their own specific way, some enumerating from 1 and others from 0, without a common uniting thread. This essay presents a point of view that builds on dimensions, boundary conditions and various inputs that, while known, are often not brought together to present a simple, consistent picture. At the same time, some surprisingly sophisticated connections are also made.
Versatile Pd(OTf)2·2H2O-Catalyzed ortho-Fluorination Using NMP as a Promoter

Pd(OTf)2·2H2O-catalyzed ortho-fluorination of triflamide-protected benzylamines is reported. The use of N-fluoro-2,4,6-trimethylpyridinium triflate as the F+ source and NMP as a promoter is crucial for this reaction. The conversion of triflamide into a wide range of synthetically useful functional groups makes this fluorination protocol broadly applicable in medicinal chemistry and synthesis.
Semi-active TMD with piezoelectric friction dampers in floor vibration control

This paper analyzes the application of semi-active variable damping TMD (SAVDTMD) with piezoelectric friction dampers as an alternative to existing methods to control floor vibrations, especially walking-induced vibrations. The use of a MDOF floor model in the analysis provides some insight on the effect of modes not targeted in the design of the controller. An optimal semi-active control law originally developed for vehicle suspension control was incorporated into the analytical models. Two floor system examples, typical of those that would have a floor vibration problem, are evaluated and shown to be controlled successfully by the SAVDTMD at both the targeted and untargeted modes. Problems of spillover of the control force to untargeted modes was analyzed and determined to be stabilizing.
Inverse problems for parabolic equations 2

Abstract Let u t − u xx = h ( t ) in 0 ⩽ x ⩽ π, t ⩾ 0. Assume that u (0, t ) = v ( t ), u (π, t ) = 0, and u ( x , 0) = g ( t ). The problem is: what extra data determine the three unknown functions {h, v, g } uniquely? This question is answered and an analytical method for recovery of the above three functions is proposed.
Unobservable Investment and the Hold‐Up Problem

We study a two-person bargaining problem in which the buyer may invest and increase his valuation of the object before bargaining. We show that if all offers are made by the seller and the time between offers is small, then the buyer invests efficiently and the seller extracts all of the surplus. Hence, bargaining with frequently repeated offers remedies the hold-up problem even when the agent who makes the relation-specific investment has no bargaining power and contracting is not possible. We consider alternative formulations with uncertain gains from trade or two-sided investment.
Searching for an invisible A ′ vector boson with DarkLight

High-luminosity experiments are able to search for new physics at low energies, which could have evaded detection thus far due to very weak couplings to the Standard Model. The DarkLight experiment at Jefferson Lab is designed to search for a new U(1) vector boson ${A}^{\ensuremath{'}}$ in the mass range 10--100 MeV through its decay ${A}^{\ensuremath{'}}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}$. In this paper, we demonstrate that DarkLight is also sensitive to an ${A}^{\ensuremath{'}}$ decaying to invisible final states. We analyze the DarkLight reach for invisible ${A}^{\ensuremath{'}}$ bosons assuming a nominal two month running time, including the possibility of augmenting the DarkLight design to include photon detection. We also propose two new analysis techniques that might prove useful for other high-luminosity searches: a cut on missing energy to improve the invariant mass resolution, and a cut on the sign of the missing invariant mass-squared to mitigate pileup. We compare the DarkLight reach to existing experimental proposals, including a complementary search using the VEPP-3 positron beam.
QR-Based Algorithm for Eigenvalue Derivatives

Many engineering optimization problems require the calculation of eigenvalue sensitivities. Several straightforward methods have been developed for calculating partial derivatives of distinct complex eigenvalues. Recent work has expanded these methods to include systems with repeated real eigenvalues. A new method is presented that embeds eigenvalue derivative computation into an established numerical eigenvalue algorithm, namely, QR decomposition. The technique is shown to have computational advantages for high-order systems.
THE EFFECT OF PAYMENT DELAYS ON STOCK PRICES

In this paper stock returns are modeled as a function of payment delays. Three hypotheses are tested: (1) that buyers compensate sellers for a six-business-day payment delay; (2) that the rate of compensation is the riskless rate; and (3) that this delay is solely responsible for day-of-the-week effects. Results support the first and second hypotheses, but not the third. The coefficient on the variable that controls for payment delays is correctly signed and statistically significant. It is the correct size in all periods but one. However, the estimated rate of compensation probably differs across days of the week. Finally, controlling for a six-business-day payment delay fails to eliminate the weekly pricing pattern.
Localized polynomial frames on the ball

Almost exponentially localized polynomial kernels are constructed on the unit ball \(B^d\) in \(\mbox{\bf R}^d\) with weights \(w_\mu(x)= (1-|x|^2)^{\mu-1/2}, \mu \ge 0\), by smoothing out the coefficients of the corresponding orthogonal projectors. These kernels are utilized to the design of cubature formulas on \(B^d\) with respect to \(w_\mu(x)\) and to the construction of polynomial tight frames in \(L^2(B^d, w_\mu)\) (called needlets) whose elements have nearly exponential localization.
Reciprocally Interlocking Boards of Directors and Executive Compensation

Is executive compensation influenced by the composition ofthe board of directors? About 8% of chief executive officers (CEOs) are reciprocally interlocked with another CEO?the current CEO of firm A serves as a director of firm B and the current CEO of firm B serves as a director of firm A. Roughly 20% of firms have at least one current or retired employee sitting on the board of another firm and vice versa. I investigate how these and other features of board composition affect CEO pay by using a sample of 9,804 director positions in America's largest companies. CEOs who lead interlocked firms earn significantly higher compensation. Also, interlocked CEOs tend to head larger firms. After controlling for firm and CEO characteristics, the pay gap is reduced dramatically. However, when firms that are interlocked due to documented business relationships are considered not interlocked, the measured return to interlock is as high as 17%. There also is evidence that the return to interlock was higher in the 1970s than in the early 1990s.
The Effects of Managed Care on Medical Referrals and the Quality of Specialty Care

This paper analyzes the role of referrals in the provision of surgical services. Primary physicians in managed care control patient access to specialists, while referrals in traditional insurance plans are less constrained. The traditional, fee-for-service insurance market is shown to achieve appropriate incentives for high quality care. In contrast, physicians with bad reputations may not lose HMO’s referrals, owing to diierences in incentives to cut costs. Empirically, we ¢nd that managed care may protect a physician whose reputation has been damaged by providing a source of referrals when shunning occurs in the FFS sector following a malpractice claim. i. introduction Primary physicians typically act as gatekeepers in the medical care of patients, referring them to surgeons and other medical specialists for advanced treatment. This paper analyzes the role of referrals as a quality assurance mechanism in the provision of surgical services. Although patients value high quality in health care, they may not be able to assess the quality oiered by individual surgeons. Nonetheless, the intermediation performed by referring practitioners may sustain high quality in the same way that reputations work for branded consumer durables [Klein and Le¥er, 1981]. Physicians pay a cost for increasing quality, but are rewarded with an increase in referrals and a higher volume practice. The ¢nancial penalties for substandard quality, on the other hand, accrue from the loss of patient volume due to shunning. Ideally, referrals serve as a shunning device to protect against negligent providers and to reduce the risk of adverse outcomes from medical care. We expect that physicians with bad reputations will be shunned by patients with traditional, fee-for-service (FFS) insurance, but it is not clear that
Submillijansky Transients in Archival Radio Observations

We report the results of a 944 epoch survey for transient sources with archival data from the Very Large Array spanning 22 years with a typical epoch separation of 7 days. Observations were obtained at 5 or 8.4 GHz for a single field of view and achieved a typical point-source detection threshold at the beam center of 300 μJy per epoch. Ten transient sources were detected with a significance threshold such that only one false positive would be expected. Of these transients, eight were detected in only a single epoch. Two transients were too faint to be detected in individual epochs but were detected in 2 month averages. None of the 10 transients was detected in longer term averages or associated with persistent emission in the deep image produced from the combination of all epochs. The cumulative rate for the short-timescale radio transients above 370 μJy at 5 and 8.4 GHz is 0.07 deg-2 yr -1 ≲ R ≲ 40 deg-2 yr-1, where the uncertainty is due to the unknown duration of the transients, 20 minutes < tchar < 7 days. A two-epoch survey for transients will detect 1.5 ± 0.4 transients per square degree above a flux density of 3 70 μJy. Two transients are associated with galaxies at z = 0.040 and z = 0.249. These may be similar to the peculiar Type Ib/c radio supernova SN 1998bw associated with GRB 980428. We detect no counterparts for six transients in deep optical and infrared imaging. The hosts and progenitors of these transients are unknown. © 2007. The American Astronomical Society. All rights reserved.
Adaptive Control of Nonlinear Attitude Motions Realizing Linear Closed Loop Dynamics

An adaptive attitude control law is presented that realizes linear closed-loop dynamics in the attitude error vector. The modified Rodrigues parameters (MRPs) are used as the kinematic variables since they are nonsingular for all possible rotations. The desired linear closed-loop dynamics can be of either PD or PID form. Only a crude estimate of the moment of inertia matrix is assumed to be known. An open-loop nonlinear control law is presented which yields linear closed-loop dynamics in terms of the MRPs. An adaptive control law is developed which asymptotically enforces these desired linear closed-loop dynamics in the presence of large inertia and external disturbance model errors. Since the unforced closed-loop dynamics are nominally linear, standard linear control methodologies can be employed to satisfy design requirements. The adaptive control law is shown to track the desired linear performance asymptotically without requiring a priori knowledge of either the inertia matrix or external disturbance.
A dynamical history of the inner Neptunian satellites

The dynamical history of Neptune's satellite system is presently inferred on the basis of a Triton capture-origin scenario in which that moon's elongated postcapture orbit generated chaotic perturbations of the original satellites' eccentricities; this, in turn, led to mutual collisions among the inner satellites until a ring of debris was formed. Neptune's inner satellite system thereby reformed on equatorial orbits after the orbtal circularization of Triton. Attention is given to the 4.7-deg inclination of 1989N6, which may be due to a temporary inclination-resonance capture.
Bootstrap confidence intervals for estimating audit value from skewed populations and small samples

Classical estimation procedures that are often used in estimating the population audit value rely on the assumption of normality. Empirical evidence suggests however, that this may not be a valid assumption. Consequently, the use of normal theory methods may lead to errone ous or misleading conclusions. The boot strap method is an effective alternative in many cases where the classical assumptions are in question. The bootstrap method replaces complex analytical techniques by computer intensive, simulation based, empirical analysis. This study illustrates the use of the bootstrap method in estimating the audit value from skewed populations and small samples. The results of Monte-Carlo simulations indicate that the bootstrap is more effective and efficient than the normal theory method.
Mammaglobin and CRxA-01 in pleural effusion cytology: potential utility of distinguishing metastatic breast carcinomas from other cytokeratin 7-positive/cytokeratin 20-negative carcinomas.

BACKGROUND The most common causes of malignant pleural effusions in women are metastatic lung carcinomas and breast carcinomas. It is often very difficult to distinguish between breast carcinomas and other metastatic carcinomas when they share a similar morphology and a similar cytokeratin profile (CK7-positive/CK20-negative [CK7+/CK20−]). To better differentiate between metastatic mammary carcinomas and other metastatic carcinomas in pleural effusion cytology, the authors studied the potential use of a novel antibody, CRxA-01, which was identified by a cDNA subtraction library, together with a well characterized antibody against mammaglobin. METHODS A computer search for patients with malignant pleural effusion specimens between January 1992 and November 2002 generated 228 patients, 71 of whom had cell block material and a known clinical history. Primary malignancies among these patients included 20 breast carcinomas, 32 lung carcinomas, 4 endometrial carcinomas, 9 ovarian carcinomas, 4 gastrointestinal carcinomas, and 2 genitourinary carcinomas. All specimens were immunostained with anti-CK7, CK20, CRxA-01, and mammaglobin antibodies. Only CK7-positive/CK20-negative (CK7+/CK20−) specimens were included in the current study, and only definitive membranous staining for CRxA-01 and cytoplasmic staining for mammaglobin were considered to be positive. RESULTS For patients with metastatic breast carcinomas, mammaglobin was positive in 11 of 20 (55%) tissue specimens and CRxA-01 was positive in 12 of 20 (60%) tissue specimens. When CRxA-01 and mammaglobin were used together, 16 of 20 (80%) tissue specimens were positive for mammaglobin or/and CRxA-01 antibodies. This staining pattern was not seen for tissue specimens from patients with other metastatic carcinomas. Two of 4 (50%) uterine carcinoma specimens and 6 of 9 (67%) ovarian carcinoma specimens were positive for CRxA-01 only. CONCLUSIONS CRxA-01 and mammaglobin were expressed in most metastatic breast carcinoma specimens. Other CK7+/CK20− carcinoma specimens did not express mammaglobin and showed weak or negative staining for CRxA-01. When used together, CRxA-01 and mammaglobin greatly improved the sensitivity and specificity for the detection of metastatic breast carcinoma in pleural effusion specimens. Cancer (Cancer Cytopathol) 2004. © 2004 American Cancer Society.