cssi/SciSciGPT-SciSciNet huggingface dataset:
Time scales for quenching single-bubble sonoluminescence in the presence of alcohols

The rate at which single-bubble sonoluminescence is quenched in the presence of alcohol is examined. Single-bubble sonoluminescence bubbles are generated in a partially degassed argon-water/alcohol mixture. Quenching rates are measured by recording the instantaneous bubble response and corresponding light emission during a sudden increase in driving pressure. The light emission intensity initially grows as the bubble settles into a steady-state. The intensity then decreases as endothermic processes begin to dominate. Quenching rates increase with the carbon chain length (C 1 -C 4 ). Complete quenching in the presence of methanol requires over 8000 acoustic cycles, while quenching with butanol occurs in about 50 acoustic cycles (driving frequency = 22.5 kHz). These observations are consistent with the view that quenching requires the repetitive injection of alcohol molecules leading to the accumulation of (hydrocarbon) gaseous products within the bubbles.
Two-loop four-gluon amplitudes in N = 4 super-Yang-Mills

Abstract Using cutting techniques we obtain the two-loop N = 4 super-Yang-Mills helicity amplitudes for four-gluon scattering in terms of scalar integral functions. The N = 4 amplitudes are considerably simpler than corresponding QCD amplitudes and therefore provide a testing ground for exploring two-loop amplitudes. The amplitudes are constructed directly in terms of gauge invariant quantities and therefore remain relatively compact throughout the calculation. We also present a conjecture for the leading color four-gluon amplitudes to all orders in the perturbative expansion.
Better Binary List Decodable Codes Via Multilevel Concatenation

A polynomial time construction of binary codes with the currently best known tradeoff between rate and error-correction radius is given. Specifically, linear codes over fixed alphabets are constructed that can be list decoded in polynomial time up to the so-called Blokh-Zyablov bound. The work builds upon earlier work by the authors where codes list decodable up to the Zyablov bound (the standard product bound on distance of concatenated codes) were constructed. The new codes are constructed via a (known) generalization of code concatenation called multilevel code concatenation. A probabilistic argument, which is also derandomized via conditional expectations, is used to show the existence of inner codes with a certain nested list decodability property that is appropriate for use in multilevel concatenated codes. A ldquolevel-by-levelrdquo decoding algorithm, which crucially uses the list recovery algorithm for the outer folded Reed-Solomon codes, enables list decoding up to the designed distance bound, aka the Blokh-Zyablov bound, for multilevel concatenated codes.
The Free Electron Laser

We review the status of our research on the Free Electron Laser© (1978) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Renormalization of polygon exchange maps arising from corner percolation

We describe a family {Ψα,β} of polygon exchange transformations parameterized by points (α,β) in the square \([0, {\frac{1}{2}}]\times[0, {\frac{1}{2}}]\). Whenever α and β are irrational, Ψα,β has periodic orbits of arbitrarily large period. We show that for almost all parameters, the polygon exchange map has the property that almost every point is periodic. However, there is a dense set of irrational parameters for which this fails. By choosing parameters carefully, the measure of non-periodic points can be made arbitrarily close to full measure. These results are powered by a notion of renormalization which holds in a more general setting. Namely, we consider a renormalization of tilings arising from the Corner Percolation Model.
Strong Room-Temperature Ferromagnetism in Co2+-Doped TiO2 Made from Colloidal Nanocrystals

Colloidal cobalt-doped TiO2 (anatase) nanocrystals were synthesized and studied by electronic absorption, magnetic circular dichroism, transmission electron microscopy, magnetic susceptibility, cobalt K-shell X-ray absorption spectroscopy, and extended X-ray absorption fine structure measurements. The nanocrystals were paramagnetic when isolated by surface-passivating ligands, weakly ferromagnetic (Ms ≈ 1.5 × 10-3 μB/Co2+ at 300 K) when aggregated, and strongly ferromagnetic (up to Ms = 1.9 μB/Co2+ at 300 K) when spin-coated into nanocrystalline films. X-ray absorption data reveal that cobalt is in the Co2+ oxidation state in all samples. In addition to providing strong experimental support for the existence of intrinsic ferromagnetism in cobalt-doped TiO2, these results demonstrate the possibility of using colloidal TiO2 diluted magnetic semiconductor nanocrystals as building blocks for assembly of ferromagnetic semiconductor nanostructures with potential spintronics applications.
One-step, three-component synthesis of highly substituted pyridines using silica nanoparticle as reusable catalyst

Abstract One-step synthesis of ‘privileged medicinal scaffolds’, 2-amino-3,5-dicarbonitrile- 6-sulfanylpyridines, has been demonstrated via a multicomponent reaction of aldehydes, malononitrile, and thiols using silica nanoparticle (NP) as catalysts. The silica NP catalysts are very mild (nearly neutral in nature), effective, environmentally benign, and retain most of their activities after being reused for three times.
Migration velocity analysis in factorized VTI media

One of the main challenges in anisotropic velocity analysis and imaging is simultaneous estimation of velocity gradients and anisotropic parameters from reflection data. Approximating the subsurface by a factorized VTI (transversely isotropic with a vertical symmetry axis) medium provides a convenient way of building vertically and laterally heterogeneous anisotropic models for prestack depthmigration.The algorithm for P‐wave migration velocity analysis (MVA) introduced here is designed for models composed of factorized VTI layers or blocks with constant vertical and lateral gradients in the vertical velocity VP0. The anisotropic MVA method is implemented as an iterative two‐step procedure that includes prestack depth migration (imaging step) followed by an update of the medium parameters (velocity‐analysis step). The residual moveout of the migrated events, which is minimized during the parameter updates, is described by a nonhyperbolic equation whose coefficients are determined by 2D semblance scanning....
Risk Spillovers and Required Returns in Capital Budgeting

This article integrates strategic product market analysis with price-taking asset pricing theory. We demonstrate that a firm's market power can lead to scale-dependent and potentially infinite required returns. Scale dependency, which we relate to risk spillovers between expansionary and existing cash flows, reflects the divergence of incremental from existing required returns. The firm-specific nature of risk spillovers potentially destroys the concept of a common industry 'risk class'. Our analysis raises important questions regarding the validity of widely used 'comparables' methods for determining risk-adjusted discount rates. Article published by Oxford University Press on behalf of the Society for Financial Studies in its journal, The Review of Financial Studies.
The Status of Hebrew in American Colleges and Universities

12:30 P.m.: Luncheon Meeting. "General Language in the Small High School." Miss Lilly Lindquist. Maison Frangaise 2:15 P.m.: Section Meetings. I. Miss Lindquist-informal discussion of problems in general language. II. "Teaching High School Pupils to Read a Foreign Language." Panel discussion led by Dr. Roy E. Mosher. III. "How Can the Languages Integrate with Other Areas in the Curriculum?" Discussion, specific examples and suggestions. Led by Mr. Rice. 3:30 P.m.: Section Meetings. I. "The Position of Grammar Study in the Modern French Course." Its importance, relative time allotment in elementary, intermediate and advanced courses. Discussion led by Mr. MacCoon. II. "Free Composition in the Second-Year French Course." Discussion led by Miss Huckans.
Stormy weather in galaxy clusters

Recent x-ray, optical, and radio observations coupled with particle and gas dynamics numerical simulations reveal an unexpectedly complex environment within clusters of galaxies, driven by ongoing accretion of matter from large-scale supercluster filaments. Mergers between clusters and continuous infall of dark matter and baryons from the cluster periphery produce long-lived “stormy weather” within the gaseous cluster atmosphere—shocks, turbulence, and winds of more than 1000 kilometers per second. This weather may be responsible for shaping a rich variety of extended radio sources, which in turn act as “barometers” and “anemometers” of cluster weather.
Three-dimensional reconstruction of skeletal muscle from MRI☆

Three-dimensional (3D) reconstructions of medical images can provide useful information to the radiologist, enabling delineation and spatial correlation of anatomic structures in one image rather than consecutive two-dimensional (2D) images. Magnetic resonance imaging (MRI) is known to be a powerful technique for evaluation of skeletal muscle pathology and physiology. We investigated the role of 3D reconstruction from MRI images of pathological and healthy muscle, using volume rendering. The ability to easily delineate and recognize normal and injured muscle in the 3D images were dependent upon the original contrast between normal and injured muscle, spatial resolution, and anatomic complexity in the original slices, and also on imaging parameters such as volume averaging.
Spurious deadweight gains

Abstract Marshallian consumer surplus (MCS) is generally an inaccurate measure of welfare change because it neglects income effects. Suppose these effects overturn the usual demand response to a price change. Then, the deadweight loss from a distortionary tax or subsidy has the wrong sign, that is, there is a spurious deadweight gain.
Altered Regulation Of β-Like Globin Genes By A Redesigned Erythroid Transcription Factor

Objective Targeted regulation of β-like globin genes was studied using designer zinc finger transcription factors containing the DNA binding domain of the red cell specific transcription factor erythroid Kruppel-like factor (EKLF) fused to repression domains. Methods Globin gene expression was analyzed after introduction of the modified transcription factors into cell lines, embryonic stem cells and transgenic mice. Results As would be predicted, when introduced transiently into cells these transcription factors were effective in repressing the adult β-globin promoter CACCC element, which is the natural target for EKLF. In murine erythroleukemia cells repression of the adult β-globin gene was accompanied by a reactivation of the endogenous embryonic βH1-globin gene. Studies in differentiated embryonic stem cells and transgenic mice confirmed the reactivation of embryonic gene expression during development. Conclusion Our studies support a competition model for β-globin gene expression and underscore the importance of EKLF in the embryonic/fetal-to-adult globin switch. They also demonstrate the feasibility of designer zinc finger transcription factors in the study of transcriptional control mechanisms at the β-globin locus and as potential gene therapy agents for sickle cell disease and related hemoglobinopathies.
Reverse orthogonal strategy for oligosaccharide synthesis

Herein, we report the invention of a novel expeditious concept for oligosaccharide synthesis. Unlike the classic orthogonal strategy based on leaving groups, the reverse approach is based on orthogonal protecting groups, herein p-methoxybenzyl and 4-pentenoyl, which allows for efficient oligosaccharide assembly in the reverse direction.
Sensitivity analysis of discrete Kalman filters.

This paper investigates the sensitivity of discrete Kalman filters to erroneous models. Both parameter and structure (state dimensionality) sensitivity are considered, as well as deterministic and random parameter errors. Iterative algorithms are derived for the calculation of the actual filter error covariance matrix for the case of known (deterministic) modelling errors. For the case of random statistical and dynamical modelling errors, an optimal mean-square error estimate of the actual system performance is derived.
Correlation analysis of the synchronizing-CA landscape

Abstract A correlation analysis will be applied to subspaces of the fitness landscape generated by the synchronization task for one-dimensional cellular automata. This results in a stochastic model that can be used to characterize the correlation structure of those subspaces. The results show that both subspaces can be characterized by an AR(2) model, both for point mutation and crossover.
Cardio-PACs: a new opportunity

It is now possible to replace film-based image management in the cardiac catheterization laboratory with a Cardiology Picture Archiving and Communication System (Cardio-PACS) based on digital imaging technology. The first step in the conversion process is installation of a digital image acquisition system that is capable of generating high-quality DICOM-compatible images. The next three steps, which are the subject of this presentation, involve image display, distribution, and storage. Clinical requirements and associated cost considerations for these three steps are listed below: Image display: (1) Image quality equal to film, with DICOM format, lossless compression, image processing, desktop PC-based with color monitor, and physician-friendly imaging software; (2) Performance specifications include: acquire 30 frames/sec; replay 15 frames/sec; access to file server 5 seconds, and to archive 5 minutes; (3) Compatibility of image file, transmission, and processing formats; (4) Image manipulation: brightness, contrast, gray scale, zoom, biplane display, and quantification; (5) User-friendly control of image review. Image distribution: (1) Standard IP-based network between cardiac catheterization laboratories, file server, long-term archive, review stations, and remote sites; (2) Non-proprietary formats; (3) Bidirectional distribution. Image storage: (1) CD-ROM vs disk vs tape; (2) Verification of data integrity; (3) User-designated storage capacity for catheterization laboratory, file server, long-term archive. Costs: (1) Image acquisition equipment, file server, long-term archive; (2) Network infrastructure; (3) Review stations and software; (4) Maintenance and administration; (5) Future upgrades and expansion; (6) Personnel.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Identification and Characterization of Faint Emission Lines in the Spectrum of the Planetary Nebula IC 418

We present high signal-to-noise ratio echelle spectra of the compact high surface brightness, low-ionization planetary nebula (PN) IC 418. These reveal 807 emission lines down to intensities less than 10-5 that of Hβ for which we determine widths and relative intensities. We show that line profiles are a valuable parameter for making line identifications and in constraining the excitation mechanism of the lines. We present evidence that indicates that many supposed high-level recombination lines may in fact be excited by a process other than recombination. We contend from the detection of dielectronic recombination lines that their relatively low intensities argue against their making a significant contribution to level populations of the heavy ions in this object. Following similar analyses of other PNe we find that IC 418 shows a small discrepancy in ion abundances derived from forbidden versus recombination lines of the heavy elements.
DEUTERON-STRIPPING REACTIONS AT HIGH ENERGY.

Abstract The bootstrap principle suggests that nuclei (B ⩾ 2) should be granted equal status in the nuclear democracy, along with the ordinary (B ⩽ 1) hadrons, simply because they interact strongly. Naively, one might expect nuclei to lie on Regge trajectories, and nuclear reactions to be dual, with resonances in the direct channel building up Regge poles in the crossed channel. With these concepts in mind, we examine in detail the simplest deuteron-stripping reactions, viz., p + p → d + π+, p + p → d + ϱ+, and p + d → d + p. Overall, the most satisfactory model is the One-Pion-Exchange (OPE) model of Yao. We present a revised version of the Yao model, and demonstrate that it gives a good description of the experimental pp → dπ forward differential cross section from threshold up to the highest energies measured. Furthermore, the model quantitatively accounts for the high-energy behaviors of the p + p → d + π and p + p → d + ϱ forward differential cross sections, which were recently found to have very puzzling high-energy behaviors. Canonical Regge behavior should set in only at much higher energies. The bumps in the resonance region of the pp → dπ cross section do not represent genuine dibaryon resonances, but are merely manifestations of Δ-isobar excitation of one of the nucleons in the deuteron. These results suggest that nuclei do not lie on Regge trajectories, although they do couple to nonexotic trajectories. The OPE mechanism can account for the pp → dπ cross section even at threshold, where the one-nucleon-exchange contribution is greatly suppressed by the p-d-n vertex form factor. To test the general validity of the OPE model, we apply it to p + d → d + p at high energy. The model gives an excellent (one-parameter) fit to the experimental differential cross section over a wide range of energies and backward angles. The excited-deuteron model of Kerman and Kisslinger is in principle equivalent to the OPE model. The OPE approximation corresponds to writing for the amplitude an unsubtracted dispersion relation in u, and then assuming that the π-N anomalous cut saturates the dispersion integral. In this approach, the absolute scale of the amplitude is calculable, whereas before it was left as a free parameter. The calculated normalization turns out to be somewhat larger than the experimental value, and to improve on this would require a much deeper understanding of the deuteron structure. Since nuclei apparently lie outside of the hadron bootstrap, we offer the speculation that nuclei may not be hadrons (strongly interacting particles) after all. Their exotic quantum numbers may render them “inert” to the SU(3)-symmetric strong force, leaving only the SU(3)-breaking medium-strong force through which they can bind together.
A Torsional Alfvén Wave Embedded Within a Small Magnetic Flux Rope in the Solar Wind

We describe and use novel techniques to analyze a striking and distinct solar wind event observed by two spacecraft. We show that the event is consistent with an interpretation as a torsional Alfven wave embedded within a small, nearly radially aligned, magnetic flux rope of total width ~106 km. It seems likely that the torsional wave was generated by distortions produced within a pre-existing flux rope that erupted from the Sun. Our examination of many events previously identified as flux ropes in the solar wind indicates that torsional Alfven waves are extremely rare in such events.
A fully four-dimensional, iterative motion estimation and compensation method for cardiac CT

Purpose: To develop a new fully four-dimensional (4D), iterative image reconstruction algorithm for cardiacCT that alternates the following two methods: estimation of a time-dependent motion vector field (MVF) of the heart from image data and reconstruction of images using the estimated MVF and projection data. Methods: Volumetric image data at different cardiac phase points were obtained using electrocardiogram-gated CT. Motion estimation (ME) and motion-compensated image reconstruction (MCR) were performed alternately until convergence was achieved. The ME method estimated the cardiac MVF using 4D nonrigid image registration between a cardiac reference phase and all the other phases. The nonrigid deformation of the heart was modeled using cubic B-splines. The cost function consisted of a sum of squared weighted differences and spatial and temporal regularization terms. A nested conjugate gradient optimization algorithm was applied to minimize the cost function and estimate the MVFs. Cardiacimages were reconstructed using a motion-tracking algorithm that utilized the MVFs estimated by the ME method. The reconstructed images supplied the input to the ME of the next iteration. The performance of the proposed method was evaluated using four patient data sets acquired with a 64-slice CT scanner. The heart rates of the patients ranged from 52 to 71 beats/min. Results: Motion artifacts were significantly reduced, and the image quality increased with the number of iterations. Without MCR, the right coronary artery (RCA) was deformed into an arc in axial images of rapid phases. With the proposed method the RCA appeared sharper and was reconstructed similar in shape to the reconstruction at the quiescent phase at mid-diastole. The boundary between the interventricular septum and the right ventricle was also clearer and sharper using the proposed algorithm. The steepness of the transition range at a rapid phase (35% R-R) was increased from 6.8 HU/pixel to 11.5 HU/pixel. The ME-MCR algorithm converged in just four iterations. Conclusion: We developed a fully 4D image reconstruction method that alternates ME and MCR algorithms in an iterative fashion. Performance tests using clinical patient data resulted in reduced motion artifacts.
The Role of Coworker and Supervisor Social Support in Alleviating the Experience of Burnout for Caregivers in the Human-Services Industry

This study focused on empathic communication and burnout (Miller, Stiff, & Ellis, 1988). Specifically, it explored the role of social support in reducing the likelihood of burnout among 112 caregivers from a human-services organization. The results revealed that social support helps caregivers provide better treatment to clients and reduces symptoms of burnout. Specifically, coworker support enhanced caregiver communicative responsiveness and supervisor support reduced caregiver perceptions of depersonalization. In addition, caregivers who reported high levels of emotional exhaustion indicated a desire to leave the organization.
Enantioselective Tsuji Allylations

The family of allylation reactions developed by Tsuji in the 1980s are capable of generating tertiary and quaternary carbon stereocenters from several synthetic precursors. Despite the utility of these transformations, they have seen little use in the synthesis of natural products. Recently, the power of these reactions was significantly enhanced by the development of enantioselective versions of these transformations. Applications of these methods to the enantioselective syntheses of natural products and pharmaceutical compounds highlight the importance of these developments.
QWalk: A quantum Monte Carlo program for electronic structure

We describe QWalk, a new computational package capable of performing quantum Monte Carlo electronic structure calculations for molecules and solids with many electrons. We describe the structure of the program and its implementation of quantum Monte Carlo methods. It is open-source, licensed under the GPL, and available at the web site http://www.qwalk.org.
THE DENSE GAS MASS FRACTION OF MOLECULAR CLOUDS IN THE MILKY WAY

The mass fraction of dense gas within giant molecular clouds (GMCs) of the Milky Way is investigated using {sup 13}CO data from the Five College Radio Astronomy Observatory Galactic Plane Surveys and the Bolocam Galactic Plane Survey (BGPS) of 1.1 mm dust continuum emission. A sample of 860 compact dust sources are selected from the BGPS catalog and kinematically linked to 344 clouds of extended (>3') {sup 13}CO J = 1-0 emission. Gas masses are tabulated for the full dust source and subregions within the dust sources with mass surface densities greater than 200 M {sub ☉} pc{sup –2}, which are assumed to be regions of enhanced volume density. Masses of the parent GMCs are calculated assuming optically thin {sup 13}CO J = 1-0 emission and local thermodynamic equilibrium conditions. The mean fractional mass of dust sources to host GMC mass is 0.11{sub −0.06}{sup +0.12}. The high column density subregions comprise 0.07{sub −0.05}{sup +0.13} of the mass of the cloud. Owing to our assumptions, these values are upper limits to the true mass fractions. The fractional mass of dense gas is independent of GMC mass and gas surface density. The low dense gas mass fraction suggests that the formation ofmore » dense structures within GMCs is the primary bottleneck for star formation. The distribution of velocity differences between the dense gas and the low density material along the line of sight is also examined. We find a strong, centrally peaked distribution centered on zero velocity displacement. This distribution of velocity differences is modeled with radially converging flows toward the dense gas position that are randomly oriented with respect to the observed line of sight. These models constrain the infall velocities to be 2-4 km s{sup –1} for various flow configurations.« less
The conjugate heat equation and Ancient solutions of the Ricci flow

Abstract We prove Gaussian type bounds for the fundamental solution of the conjugate heat equation evolving under the Ricci flow. As a consequence, for dimension 4 and higher, we show that the backward limit of Type I κ -solutions of the Ricci flow must be a non-flat gradient shrinking Ricci soliton. This extends Perelmanʼs previous result on backward limits of κ -solutions in dimension 3, in which case the curvature operator is nonnegative (it follows from Hamilton–Ivey curvature pinching estimate). As an application, this also addresses an issue left in Naber (2010) [23] , where Naber proves the interesting result that there exists a Type I dilation limit that converges to a gradient shrinking Ricci soliton, but that soliton might be flat. The Gaussian bounds that we obtain on the fundamental solution of the conjugate heat equation under evolving metric might be of independent interest.
Ergodicity of the adic transformation on the Euler graph

The Euler graph has vertices labelled (n, k) for n = 0, 1, 2, ... and k = 0, 1, ..., n, with k + 1 edges from (n, k) to (n + 1, k) and n − k + 1 edges from (n, k) to (n + 1, k + 1). The number of paths from (0,0) to (n, k) is the Eulerian number A(n, k), the number of permutations of 1,2,...,n+ 1 with exactly n− k falls and k rises. We prove that the adic (Bratteli-Vershik) transformation on the space of infinite paths in this graph is ergodic with respect to the symmetric measure. 1. The Euler Graph The Euler graph is an infinite directed graph such that at level n there are n + 1 vertices labelled (n, 0) through (n, n). The vertex (n, k) has n+ 2 total edges leaving it, with k + 1 edges connecting it to vertex (n+ 1, k) and n− k + 1 edges connecting it to vertex (n+ 1, k + 1). Define X to be the space of infinite edge paths on the Euler graph. X is a compact metric space in a natural way: if two paths x = x0x1x2... and y = y0y1y2... agree for all n less than j and xj 6= yj , then define d(x, y) = 2 −j . The number of paths from the root vertex (0,0) to the vertex (n, k) is the Eulerian number, A(n, k), which is the number of 2 S. Bailey, M. Keane, K. Petersen, and I. Salama
Measurement of the positron--electron ratio in the primary cosmic rays from 5 to 50 GeV

We report the first measurement of primary-cosmic-ray positrons above 5 GeV. Both ${e}^{+}$ and ${e}^{\ensuremath{-}}$ fluxes were measured, using a balloon-borne magnetic spectrometer. Background was suppressed using a new technique which combines both selective trigger and identification of bremsstrahlung photons created by ${e}^{\ifmmode\pm\else\textpm\fi{}}$ upon entering the instrument. If no positrons originate at cosmic-ray sources, our observed ratio $\frac{{e}^{+}}{({e}^{+}+{e}^{\ensuremath{-}})}=0.08\ifmmode\pm\else\textpm\fi{}0.02$ requires source protons to traverse 3.5\ifmmode\pm\else\textpm\fi{}1.5 g/${\mathrm{cm}}^{2}$ of interstellar material.
Wobble Board Rehabilitation for Improving Balance in Ankles With Chronic Instability.

Objective:To quantify improvements in clinical impairments using a wobble board rehabilitation protocol for chronic ankle instability (CAI).Design:Prospective randomized controlled trial.Setting:Laboratory.Patients:Thirty-four participants with “giving way” and history of ankle sprains were randomly
How Anti-Juvenile Hormones Work

Synopsis. Two compounds which possess anti-juvenile hormone activity in insects have been isolated and identified from the plant Ageratum houstonianum. These compounds, called precocenes, have been shown to inhibit the development ofthe insect corpus allatum (CA) and/or destroy the CA in sensitive species. The action of the precocenes can be seen to affect only those CA which are actively synthesizing and secreting the juvenile hormone. Structure-optimization studies of the precocenes reveal that the 3,4-double bond must be present and unsubstituted for biological activity to occur. In vivo and in vitro studies reveal that the precocenes are very probably converted into reactive epoxides which undergo facile reaction with nucleophiles since histological examination of precocene-inactivated CAs indicate a direct cytotoxic action of the precocenes on the parenchymal cells of the CA. The most likely mode of action would appear to involve the alkylation of macromolecular cellular elements by a reactive epoxide or similar activated precocene inter? mediate.
Cameron–Liebler line classes

New examples of Cameron–Liebler line classes in PG(3, q) are given with parameter \({\frac{1}{2}(q^2 -1)}\) . These examples have been constructed for many odd values of q using a computer search, by forming a union of line orbits from a cyclic collineation group acting on the space. While there are many equivalent characterizations of these objects, perhaps the most significant is that a set of lines \({\fancyscript{L}}\) in PG(3, q) is a Cameron–Liebler line class with parameter x if and only if every spread \({\fancyscript{S}}\) of the space shares precisely x lines with \({\fancyscript{L}}\) . These objects are related to generalizations of symmetric tactical decompositions of PG(3, q), as well as to subgroups of PΓL(4, q) having equally many orbits on points and lines of PG(3, q). Furthermore, in some cases the line classes we construct are related to two-intersection sets in AG(2, q). Since there are very few known examples of these sets for q odd, any new results in this direction are of particular interest.
Regio- and Stereoselective Synthesis of Fluoroalkenes by Directed Au(I) Catalysis

Au-catalyzed hydrofluorination reactions of a range of functionalized alkynes are reported. In the presence of an appropriate directing group, localized with particular spacing from the pendant alkyne, regioselective and predictable conversion of the alkyne to the Z-vinyl fluoride may be achieved. In selected cases, yields and selectivities are excellent. Additional experiments with two directing groups installed have established some initial principles with respect to a hierarchy of directing groups and their capacity for influencing hydrofluorination regioselectivity.
Analysis and design of minimax-optimal interpolators

We consider a class of interpolation algorithms, including the least-squares optimal Yen (1956) interpolator, and we derive a closed-form expression for the interpolation error for interpolators of this type. The error depends on the eigenvalue distribution of a matrix that is specified for each set of sampling points. The error expression can be used to prove that the Yen interpolator is optimal. The implementation of the Yen algorithm suffers from numerical ill conditioning, forcing the use of a regularized, approximate solution. We suggest a new, approximate solution consisting of a sinc-kernel interpolator with specially chosen weighting coefficients. The newly designed sinc-kernel interpolator is compared with the usual sinc interpolator using Jacobian (area) weighting through numerical simulations. We show that the sinc interpolator with Jacobian weighting works well only when the sampling is nearly uniform. The newly designed sinc-kernel interpolator is shown to perform better than the sinc interpolator with Jacobian weighting.
A design procedure for solar air heating systems

A natural extension of the design procedure for liquid-based solar space and water heating systems is a similar analysis for solar heating systems using air as the heat transfer fluid. In this paper, a solar air heating system incorporating a flat-plate air heater and packed bed thermal storage is described and a simulation model for the system is developed. The results of many simulations of the air heating system are used to establish the relationship between system performance and the system design and meteorological variables. The results are presented in analytic and graphical form, referred to as an f-chart for solar air heating systems. The results of simulations in several widely different climates suggest that the information presented in the f-chart is location independent. Methods of estimating the performance of air heating systems having a collector air capacitance rate and a storage capacity other than those used to generate the f-chart are included. A comparison of the performance of air and liquid based systems is afforded by a comparison of their respective f-charts. The air system is shown to perform better at high load fractions supplied by solar energy than a liquid-based system with the same collector thermal performance parameters.
Vibration Analysis of Bladed Disc Assemblies

Abstract The dynamic behavior of a bladed disc assembly is examined by developing a finite element model (FEM). The object of this work is to develop an understanding of the dynamic behavior of the system with respect to the various boundary conditions. The analysis includes variation of the boundary conditions at the blade-disc interface, between adjacent blades, and at the shroud. It is clearly shown that only certain mode patterns are affected with respect to a particular boundary condition, leaving the remaining modes unchanged. The quantitative effect of the various boundary conditions is calculated by finite element analysis of a cyclic symmetric model. A methodology is also presented where the associated modes of the higher harmonics resonant frequencies of the assembly are identified in a systematic and automated way without being plotted and viewed. This methodology, which uses the cross-orthogonality equations, is valuable in analyzing systems with a large number of nodal diameters, where the co...
Performance of algebraic multigrid methods for non-symmetric matrices arising in particle methods

Large linear systems with sparse, non-symmetric matrices are known to arise in the modeling of Markov chains or in the discretization of convection–diffusion problems. Due to their potential of solving sparse linear systems with an effort that is linear in the number of unknowns, algebraic multigrid (AMG) methods are of fundamental interest for such systems. For symmetric positive definite matrices, fundamental theoretical convergence results are established, and efficient AMG solvers have been developed. In contrast, for non-symmetric matrices, theoretical convergence results have been provided only recently. A property that is sufficient for convergence is that the matrix be an M-matrix. In this paper, we present how the simulation of incompressible fluid flows with particle methods leads to large linear systems with sparse, non-symmetric matrices. In each time step, the Poisson equation is approximated by meshfree finite differences. While traditional least squares approaches do not guarantee an M-matrix structure, an approach based on linear optimization yields optimally sparse M-matrices. For both types of discretization approaches, we investigate the performance of a classical AMG method, as well as an algebraic multilevel iteration (AMLI) type method. While in the considered test problems, the M-matrix structure turns out not to be necessary for the convergence of AMG, problems can occur when it is violated. In addition, the matrices obtained by the linear optimization approach result in fast solution times due to their optimal sparsity. Copyright © 2010 John Wiley & Sons, Ltd.
Tannakian duality for Anderson–Drinfeld motives and algebraic independence of Carlitz logarithms

We develop a theory of Tannakian Galois groups for t-motives and relate this to the theory of Frobenius semilinear difference equations. We show that the transcendence degree of the period matrix associated to a given t-motive is equal to the dimension of its Galois group. Using this result we prove that Carlitz logarithms of algebraic functions that are linearly independent over the rational function field are algebraically independent.
Star Formation Relations in Nearby Molecular Clouds

We test some ideas for star formation relations against data on local molecular clouds. On a cloud by cloud basis, the relation between the surface density of star formation rate and surface density of gas divided by a free-fall time, calculated from the mean cloud density, shows no significant correlation. If a crossing time is substituted for the free-fall time, there is even less correlation. Within a cloud, the star formation rate volume and surface densities increase rapidly with the corresponding gas densities, faster than predicted by models using the free-fall time defined from the local density. A model in which the star formation rate depends linearly on the mass of gas above a visual extinction of 8 mag describes the data on these clouds, with very low dispersion. The data on regions of very massive star formation, with improved star formation rates based on free-free emission from ionized gas, also agree with this linear relation.
Addressing the unmet need for visualizing conditional random fields in biological data

The biological world is replete with phenomena that appear to be ideally modeled and analyzed by one archetypal statistical framework - the Graphical Probabilistic Model (GPM). The structure of GPMs is a uniquely good match for biological problems that range from aligning sequences to modeling the genome-to-phenome relationship. The fundamental questions that GPMs address involve making decisions based on a complex web of interacting factors. Unfortunately, while GPMs ideally fit many questions in biology, they are not an easy solution to apply. Building a GPM is not a simple task for an end user. Moreover, applying GPMs is also impeded by the insidious fact that the “complex web of interacting factors” inherent to a problem might be easy to define and also intractable to compute upon. We propose that the visualization sciences can contribute to many domains of the bio-sciences, by developing tools to address archetypal representation and user interaction issues in GPMs, and in particular a variety of GPM called a Conditional Random Field(CRF). CRFs bring additional power, and additional complexity, because the CRF dependency network can be conditioned on the query data. In this manuscript we examine the shared features of several biological problems that are amenable to modeling with CRFs, highlight the challenges that existing visualization and visual analytics paradigms induce for these data, and document an experimental solution called StickWRLD which, while leaving room for improvement, has been successfully applied in several biological research projects. Software and tutorials are available at http://www.stickwrld.org/
Conformal Edge Currents in Chern-Simons Theories

We develop elementary canonical methods for the quantization of Abelian and non-Abelian Chern-Simons actions, using well-known ideas in gauge theories and quantum gravity. Our approach does not involve choice of gauge or clever manipulations of functional integrals. When the spatial slice is a disc, it yields Witten’s edge states carrying a representation of the Kac-Moody algebra. The canonical expressions for the generators of diffeomorphisms on the boundary of the disc are also found, and it is established that they are the Chern-Simons version of the Sugawara construction. This paper is a prelude to our future publications on edge states, sources, vertex operators, and their spin and statistics in 3D and 4D topological field theories.
Group actions on Banach spaces and a geometric characterization of a-T-menability

Abstract We prove a geometric characterization of a-T-menability through proper, affine, isometric actions on the Banach spaces L p [ 0 , 1 ] for 1 p 2 . This answers a question of A. Valette.
Balanced‐Budget Rules, Distortionary Taxes, and Aggregate Instability

A traditional argument against a balanced‐budget fiscal policy rule is that it amplifies business cycles by stimulating aggregate demand during booms via tax cuts and higher public expenditures and by reducing demand during recessions through a corresponding fiscal contraction. This paper suggests an additional source of instability that may arise from this type of fiscal policy rule. It shows that, within the standard neoclassical growth model, a balanced‐budget rule can make expectations of higher tax rates self‐fulfilling if the fiscal authority relies heavily on changes in labor income taxes to eliminate short‐run fiscal imbalances. Calibrated versions of the model show that indeterminacy occurs for income tax rates that are empirically plausible for the U.S. economy and other Group of Seven countries.
Interfacial Structure of In/Pt/GaAs Heterojunction Ohmic Contacts

Graded heterojunction InGaAs ohmic contacts to n-GaAs have been prepared which show improved electrical and morphological properties compared with other diffused contacts. The improvements result primarily from the use of a thin 400 A Pt layer between the 4000 A In layer and the substrate to control the reaction of the In and the GaAs. A study of chemically etched samples using energy dispersive x-ray (EDX) analysis has revealed the formation of a smooth InxGa1−xAs heterojunction interface. Evidence is also presented that the heterojunction regions are epitaxial. A smooth, uniform interface of this type is not formed in other diffused contact systems, such as In/GaAs and Ni/Au-Ge/GaAs.
An Approach to Organizing a Management Accounting Curriculum

In recent years, numerous tools such as activity‐based costing, the balanced scorecard, and target costing have gained prominence within business organizations (Kaplan and Cooper 1998; Kaplan and Norton 1996; Ansari et al. 1997). Nonetheless, traditional management accounting practices such as standard costing and contribution margin analysis continue to be prevalent (Szendi and Elmore 1993). The traditional topics, when coupled with all the recent advancements, create a sizable body of knowledge that presents a challenge to management accounting educators, who bear the responsibility of organizing this subject matter into a coherent whole. In an effort to aid professors wrestling with this challenge, this article presents a new framework for organizing an entire management accounting curriculum. The article also includes one possible application of the framework that is being used at Miami University. The benefits of adopting the framework include: (1) less redundancy within the curriculum, (2) logical d...
X-Ray and Optical Microlensing in the Lensed Quasar PG 1115+080

We analyzed the microlensing of the X-ray and optical emission of the lensed quasar PG 1115+080. We find that the effective radius of the X-ray emission is -->1.3+ 1.1−0.5 dex smaller than that of the optical emission. Viewed as a thin disk observed at inclination angle i, the optical accretion disk has a scale length, defined by the point where the disk temperature matches the rest-frame energy of the monitoring band ( -->kT = hc/λrest with -->λrest = 0.3 μm), of log{(rs, opt/cm)[cos(i)/0.5]½} = 16.6 ± 0.4$log b\{ (rs,opt/cm) [cos (i)/0.5]1/2b\} = 16.6 ± 0.4$ -->. The X-ray emission region (1.4-21.8 keV in the rest frame) has an effective half-light radius of -->log (r1/2,X/cm) = 15.6+ 0.6−0.9. Given an estimated black hole mass of -->1.2 × 109 M☉, corresponding to a gravitational radius of -->log (rg/cm) = 14.3, the X-ray emission is generated near the inner edge of the disk, while the optical emission comes from scales slightly larger than those expected for an Eddington-limited thin disk. We find a weak trend supporting models with low stellar mass fractions near the lensed images, in mild contradiction to inferences from the stellar velocity dispersion and the time delays.
Nonlinear Pricing to Produce Information

We investigate the firm's dynamic nonlinear pricing problem when facing consumers whose tastes vary according to a scalar index. We relax the standard assumption that the firm knows the distribution of this index. In general the firm should determine its marginal price schedule as if it were myopic, and produce information by lowering the price schedule; "bunching" consumers at positive purchase levels should be avoided. As a special case we also consider a market characterized by homogeneous consumers with a static, but unknown, demand curve. We show that when there are repeat purchases the forward-looking firm should tend towards penetration pricing; otherwise its strategy should tend towards skimming. We extend our insights to more general settings and discuss implications for pricing product lines.
New monotonicity formulas for Ricci curvature and applications. I

We prove three new monotonicity formulas for manifolds with a lower Ricci curvature bound and show that they are connected to rate of convergence to tangent cones. In fact, we show that the derivative of each of these three monotone quantities is bounded from below in terms of the Gromov–Hausdorff distance to the nearest cone. The monotonicity formulas are related to the classical Bishop–Gromov volume comparison theorem and Perelman’s celebrated monotonicity formula for the Ricci flow. We will explain the connection between all of these. Moreover, we show that these new monotonicity formulas are linked to a new sharp gradient estimate for the Green function that we prove. This is parallel to the fact that Perelman’s monotonicity is closely related to the sharp gradient estimate for the heat kernel of Li–Yau. In [CM4] one of the monotonicity formulas is used to show uniqueness of tangent cones with smooth cross-sections of Einstein manifolds. Finally, there are obvious parallelisms between our monotonicity and the positive mass theorem of Schoen–Yau and Witten.
State Attorneys General, Entrepreneurship, and Consumer Protection in the New Federalism

Although many scholars have acknowledged the important role of states in regulatory enforcement, few have studied the decisions of the state attorneys general to pursue particular multi-state litigation actions. State attorneys general act as political entrepreneurs because they aggressively seek out market failures in society to justify stronger regulation. Their motivation to serve the public comes from the fact that they are elected in 43 states and the office is often used as a springboard into higher political office. A probit model analyzing the decision to join seven high-profile multi-state enforcement actions that look place between 1996 and 1998 reveals that state citizen ideology and the institutional structure of the office have the strongest effects on the decision to join a case. Copyright 2003, Oxford University Press.