cssi/SciSciGPT-SciSciNet huggingface dataset:
Synthesis and alkaline hydrolysis of (pentafluoroethyl)imidazoles

Abstract Photochemical ring substitution of the N-trifluoroacetyl derivatives of histamine and of L-histidine methyl ester by pentafluoroethyl radical provides the corresponding 2- and 4-pentafluoroethylated products in yields of 19% and 27%, respectively. Alkaline hydrolysis converts the 2-pentafluoroethyl group to trifluoroacetyl. The reaction mechanism, involving a diazafulvene intermediate, is analogous to that elucidated for (trifluoromethyl)imidazoles; however, the pentafluoroethyl group is markedly more reactive to hydrolysis than the trifluoromethyl group. For imidazole derivatives, the ratio of reactivities is 75 at C-2 and 40 at C-4. The hydrolysis of 4-(pentafluoroethyl)histamine affords the bicyclic product, 4-(trifluoromethyl)-6,7-dihydro-1H-imidazo[4,5-c]-pyridine in 65.4% yield.
Interval arithmetic determinant evaluation and its use in testing for a Chebyshev system

Two recent papers, one by Hansen and one by Hansen and R. R. Smith, have shown how Interval Arithmetic (I.A.) can be used effectively to bound errors in matrix computations. In the present paper a method proposed by Hansen and R. R. Smith is compared with straightforward use of I.A. in determinant evaluation. Computational results show the accuracy and running times that can be expected when using I.A. for determinant evaluation. An application using I.A. determinants in a program to test a set of functions to see if they form a Chebyshev system is then presented.
The interaction between public and private R&D expenditure and national productivity

Starting from the epistemological position of the positive interaction between public and private R&D expenditures at country level for maintaining productivity growth, the purpose of this paper is to provide empiricist–positivist arguments of this stance in order to design R&D policy that supports national competitiveness in fast-changing and turbulent markets
Asymmetric synthesis of camptothecin alkaloids: A nine-step synthesis of (S)-camptothecin

Abstract DE Ring camptothecin intermediate II was prepared enantioselectively from 2-chloro-6-hydroxypyridine in six steps and used in a nine-step synthesis of (S)-camptothecin.
All-Fiber Acousto-Optic Frequency Shifter Using Two-Mode Fiber

An all fiber single-sideband frequency shifter using acousto-optic interaction in a double-moded fiber has been developed. Conversion efficiency of 100% with 35 dB suppression of the carrier and image sideband has been achieved at a frequency of 8 MHz using an input electrical power of 100mW.© (1987) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Scheduling sales force training: Theory and evidence

To have a productive sales force, firms must provide their salespeople with sales training. But from a profit-maximizing perspective, there are also reasons to limit training: training is expensive, it has diminishing returns, and trained salespeople need to be compensated at a higher level since their value in the outside labor market has increased. Due to these reasons, the following inter-related questions are not straightforward to answer: (1) How much training should be provided and how should training be scheduled over time? (2) How should compensation vary with training? (3) Should salespeople be asked to pay for some or all of their training? An analytical model is developed and analyzed using optimal control theory to provide answers to these questions. Thereafter, an empirical investigation is undertaken that broadly corroborates the analytical findings.
Improved Noisy Population Recovery, and Reverse Bonami-Beckner Inequality for Sparse Functions

The noisy population recovery problem is a basic statistical inference problem. Given an unknown distribution in {0,1}n with support of size k, and given access only to noisy samples from it, where each bit is flipped independently with probability (1-μ)/2, estimate the original probability up to an additive error of e. We give an algorithm which solves this problem in time polynomial in (klog log k, n, 1/e). This improves on the previous algorithm of Wigderson and Yehudayoff [FOCS 2012] which solves the problem in time polynomial in (klog k, n, 1/e). Our main technical contribution, which facilitates the algorithm, is a new reverse Bonami-Beckner inequality for the L1 norm of sparse functions.
Frailty and Age-related Macular Degeneration: The Beaver Dam Eye Study

Purpose To investigate the associations of measures of frailty to prevalent age-related maculopathy (ARM). Design Cross-sectional population-based study. Methods Time to walk a measured course (gait-time), handgrip strength, peak expiratory flow rate, ability to stand from a sitting position without using arms, self-reported co-morbidities, and ARM were assessed at the third examination of the Beaver Dam Eye Study (n = 2,962). ARM was determined by grading stereoscopic color fundus photographs. Results While controlling for age, smoking, and the number of co-morbid conditions, weaker handgrip strength was associated with early ARM (odds ratio [OR]/10 kg decrease 1.28, confidence interval [CI] 1.08, 1.52, P = .004) and late ARM (OR 1.55, 95% CI 1.02, 2.36) in men but not women. Other measures of frailty were not related to ARM. Conclusions A weak cross-sectional association of handgrip strength with ARM (in men) was found after controlling for co-morbid conditions. These data suggest that ARM is due to a specific disease process, albeit age-related, rather than to biologic aging, as reflected by measures of frailty.
Synthesis, Characterization, and Reactions of Mono and Bicyclic Phostones

Abstract Improved methods for the synthesis of 5- and 6-membered ring phostones 2 and 1 as well as original preparations of bicyclic phostones 4 (n=1,2) have been successfully executed. The preparation of the 4-membered ring 3 was more elusive, but the observed products indicated its presence as an intermediate which underwent further transformations. Reaction of 1 with 2,2,6,6-tetramethylpiperidide at low temperature, followed by treatment with a variety of alkyl halides gave the expected alkylation products whose cis/trans stereochemistry was dependent on the reaction conditions. Subsequent ring closure of the cis or trans alkylated product 10, gave only the cis fused bicyclic product 4. In fact, other synthetic routes to 4 produced only the cis isomer. The mechanisms and stereochemistry of these various conversions will be discussed.
Predetermined Prices and the Allocation of Social Risks

We propose a Walrasian explanation for the existence of fixed prices, i.e., of trades in which either the price or the quantity exchanged does not reflect all publicly available information. Such trades result in a rigid price system that facilitates the sharing of social risks; they may also cause allocative distortions that increase the equilibrium price of insurance above its actuarially fair level. We demonstrate that the market for noncontingent claims is active only when this insurance "gain" outweighs the "cost" of allocative distortions. Fixed price equilibria are constrained optima, i.e., they cannot be dominated by an appropriately constrained central planner.
Combining knowledge sources to reorder N-best speech hypothesis lists

A simple and general method is described that can combine different knowledge sources to reorder N-best lists of hypotheses produced by a speech recognizer. The method is automatically trainable, acquiring information from both positive and negative examples. In experiments, the method was tested on a 1000-utterance sample of unseen ATIS data.
A Different Short Proof of Brooks’ Theorem

Lov\'asz gave a short proof of Brooks' theorem by coloring greedily in a good order. We give a different short proof by reducing to the cubic case. Then we show how to extend the result to (online) list coloring via the Kernel Lemma.
The language-of-thought relation and its implications

L'A. definit ce qu'il appelle la relation du langage de la pensee qui designe la relation d'une personne a un langage, de telle sorte que ce langage soit celui de la pensee de la personne, c'est-a-dire de son systeme interne de representation mentale. L'A. traite en particulier de la semantique compositionnelle et de la nature des propositions. Dans l'article suivant intitule «Thinking in Neurons: Comments on S. Schiffer's The Language-of-Thought», T. Yagisawa critique l'emploi des theories de la survenance compositionnelle. Dans l'article suivant intitule «Reply to Yagisawa», l'A. repond point par point a la critique qui lui a ete faite
The Physical Conditions of the X-Ray Emission Line Regions in the Circinus Galaxy

We present a detailed X-ray spectral analysis of the Circinus galaxy using archival data obtained with the ASCA satellite. The spectrum shows numerous emission lines in the soft X-ray band from highly ionized ions, as well as Compton reflection and fluorescent lines from neutral or near-neutral matter. We analyze the spectrum in the context of a self-consistent recombination cascade model and find that a nearly flat differential emission measure (DEM) distribution in ionization parameter fits the data. For a fixed solid angle distribution of matter surrounding a point source, this corresponds to a run of electron density of the form n(r) ~ r-3/2, which is suggestive of Bondi accretion onto a central compact mass. Using this density profile and comparing the resulting emission spectra with the ASCA data, the size of the X-ray emission line region is estimated to be 1 kpc. We also show that the derived density as a function of radius is compatible with the X-ray recombination line emission region being the confining medium of the coronal line regions.
Dusty Rings: Signposts of Recent Planet Formation

Many nearby stars are surrounded by a bright ring or disk of cold dust. Our calculations show that these disks and rings of dust are signposts of recent planet formation. Bright rings appear because dust associated with the formation of a planet absorbs and scatters light from the central star. The calculations explain the rings observed so far and predict that all nascent solar systems have dusty rings.
Ground-Coupled Heat and Moisture Transfer from Buildings Part 1–Analysis and Modeling*

Ground-heat transfer is tightly coupled with soil-moisture transfer. The coupling is threefold: heat is transferred by thermal conduction and by moisture transfer; the thermal properties of soil are strong functions of the moisture content; and moisture phase change includes latent heat effects and changes in thermal and hydraulic properties. A heat and moisture transfer model was developed to study the ground-coupled heat and moisture transfer from buildings. The model also includes detailed considerations of the atmospheric boundary conditions, including precipitation. Solutions for the soil temperature distribution are obtained using a finite element procedure. The model compared well with the seasonal variation of measured ground temperatures.
Efficacy of Tadalafil in the Treatment of Erectile Dysfunction in Hypertensive Men on Concomitant Thiazide Diuretic Therapy

Many men with erectile dysfunction (ED) have hypertension as a comorbid condition. Recent guidelines recommend thiazide diuretics as first-line therapy for hypertension. We analyzed data from 14 randomized, double-blind, placebo-controlled trials (N=2501) to evaluate the efficacy of tadalafil 20 mg for the treatment of ED in men on thiazides. Of the 2501 patients, 163 were on concomitant thiazides (116 tadalafil/47 placebo) and 159 (98%) were reported to have hypertension. The primary efficacy measures were mean change from baseline in the international index of erectile function (IIEF) erectile function (EF) domain and the proportion of 'yes' responses to sexual encounter profile (SEP) Questions 2 and 3. The tadalafil group showed a significantly (P 0.05).
Percutaneous paravalvular leak closure.

Paravalvular leak (PVL) is a known complication of surgical and transcatheter valve replacement procedures. Patients most commonly present with congestive heart failure and/or hemolysis, and repeat surgical procedures to correct the PVL carries increased risk with reduced likelihood of success. As a result, percutaneous approaches to PVL closure have been developed, with a considerable emphasis on multimodality imaging for both diagnosis and procedural guidance in the cardiac catheterization laboratory. Large series’ of percutaneous PVL closure have been recently published, with encouraging results with respect to both procedural success and clinical outcomes. In this paper, we provide a comprehensive review of imaging and procedural techniques for percutaneous PVL closure and present the data supporting this novel treatment strategy.
On the distances of planetary nebulae

Reconsidering calibration of statistical distance scales for planetary nebulae leads naturally to examining precision and especially the systematic errors of other methods. Here we present a different calibration strategy based on the precise trigonometric parallaxes for sixteen central stars published by Harris et al. (2007) of USNO, with four improved by Benedict et al. using the Hubble Space Telescope. We tested various other methods against those and each other. The statistical scales tested – Cahn et al. (1992), Zhang (1995), Frew (2008), and Stanghellini et al. (2008) – all show signs of radius dependence (i.e. distance ratio [scale/true] depends on nebular radius). Almost all have overall systematic error; Frew’s mean statistical scale seems free of that and also perhaps a scale of Zhang’s based on brightness temperature. Systematic errors were introduced by choices of data sets for calibration, by methodologies used, and by assumptions made about the nebulae. Some spectroscopic parallaxes published by Ciardullo et al. (1999) seem consistent with the trigonometric ones where the objects overlap in nebular radius. Pottasch’s (1996) earlier spectroscopic parallaxes, on the other hand, underestimate distance consistently by a factor of two, probably because of a calibration difference. ‘Gravity’ distances seem to be overestimated by 40-50 per cent for nearby objects but may be underestimated for distant objects. Angular expansion distances appear to be suitable for calibration after correction for astrophysical effects (e.g. Mellema 2004). In particular the measurements by Hajian and collaborators using the VLA seem to yield fairly accurate distances after correction by Frew. Extinction distances appear to be often unreliable individually though sometimes approximately correct overall. Comparison of the Hipparcos parallaxes (van Leeuwen 2007) for large planetaries with our ‘best estimate’ distances confirms that those parallaxes are overestimated by a factor 2.5, as suggested by Harris et al.’s result for PHL 932. The ultimate goal is an accurate and internally consistent set of distances for planetaries. However, some of our tools and analysis can also be applied in distance scale comparisons utilizing parallaxes and/or distances for other objects as well.
On the origin of the mass gap for non-Abelian gauge theories in (2+1) dimensions

Abstract An analysis of how the mass gap could arise in pure Yang-Mills theories in two spatial dimensions is given.
Fast Tides in Slow Stars: The Efficiency of Eddy Viscosity

Turbulent viscosity is believed to circularize and synchronize binary orbits and to damp stellar oscillations. Older binaries appear to be circular out to longer periods, which indicates that circularization proceeds during the main-sequence phase. It is also believed that when the tidal period is shorter than the turnover time of the largest eddies, turbulent viscosity is partially suppressed. The degree of suppression, however, is disputed. We reexamine both of these beliefs via (1) direct perturbative calculations, linearizing the fluid equations on a turbulent background; and (2) numerical integration of a chaotic dynamical system subject to periodic forcing. We find that dissipation of rapid tides is severely suppressed. Even when we disregard this suppression, we conclude that some mechanism other than turbulent convection circularizes solar-type binaries.
Guiding Cooperative Stakeholders to Compromise Solutions Using an Interactive Tradespace Exploration Process

Engineering projects frequently involve the cooperation of multiple stakeholders with varying objectives and preferences for the resulting system. Finding a mutually agreeable solution is of paramount importance in order to assure the successful completion of these projects, particularly when different stakeholders are splitting the costs because none can afford to finance the project on their own. This paper proposes a process for uncovering potential mutually agreeable solutions between conflicting stakeholders, without relying on hypothetical aggregate or super-stakeholder preferences, by using guided individual preference compromises and efficiency tradeoffs. Opportunities for experimentally testing the process, with results investigating its usability and solution quality, are discussed. Further directions to improve and expand the process are also discussed, with attention paid to the design of the process as it relates to promoting an implied concept of “goodness” or “fairness” of compromise along with the ability of the process to incorporate advanced interactive technology to improve knowledge retention and understanding of the participating stakeholders.
The optical and ultraviolet spectral energy distributions of short-period black hole X-ray transients in outburst

We compile optical and UV spectra of a sample of "typical" short-period black hole X-ray transients in outburst. We also survey determinations of interstellar extinction and distance to deredden spectra and compare absolute fluxes. Hence, we perform a comparative study of the broadband spectral energy distributions (SEDs). We find that, given such a homogeneous sample of typical sources, the optical SEDs form a relatively uniform set, all exhibiting quasi-power-law spectra with Fν ∝ να, where 0.5 α 1.5 (steeper than the canonical ν1/3 disk spectrum). All become flatter in the UV, although there is more diversity here. The SEDs studied can be broadly divided into two optical-UV spectral states. The UV-hard spectra, e.g., A0620-00 and GS 1124-684, continue to rise in the far-UV. The UV-soft spectra, e.g., GRO J0422+32, drop off. XTE J1859+226 evolved from UV-soft to UV-hard as it decayed, indicating that this effect is a real difference, not a dereddening artifact. All the spectra can be fitted by a generalized blackbody disk model with two forms of heating, resulting in the two states. The UV-soft state is consistent with a disk illuminated by a central point source, with irradiative heating dominating over viscous. The UV-hard state is well described by a viscously heated disk, although this requires very high mass flow rates in the case of GS 1124-684. Alternatively, a UV-hard spectrum can be produced if the disk is illuminated by a vertically extended X-ray source such as a central scattering corona or jet. Since scattering is assumed by some numerical simulations, it is worth emphasizing that when illumination comes from (nonlocal) scattering high above the disk, we generically expect a steeper radial dependence of X-ray heating (F ∝ R-3) than is usually assumed; it is this steep dependence that leads to the UV-hard spectrum.
Poincare recurrences and topological diversity

Finite entropy thermal systems undergo Poincare recurrences. In the context of field theory, this implies that at finite temperature, timelike two-point functions will be quasi-periodic. In this note we attempt to reproduce this behavior using the AdS/CFT correspondence by studying the correlator of a massive scalar field in the bulk. We evaluate the correlator by summing over all the SL(2,) images of the BTZ spacetime. We show that all the terms in this sum receive large corrections after at certain critical time, and that the result, even if convergent, is not quasi-periodic. We present several arguments indicating that the periodicity will be very difficult to recover without an exact re-summation, and discuss several toy models which illustrate this. Finally, we consider the consequences for the information paradox.
Palladium-Catalyzed Coupling Reactions of Aryl Chlorides

Collectively, palladium-catalyzed coupling reactions represent some of the most powerful and versatile tools available to synthetic organic chemists. Their widespread popularity stems in part from the fact that they are generally tolerant to a large number of functional groups, which allows them to be employed in a wide range of applications. However, for many years a major limitation of palladium-catalyzed coupling processes has been the poor reactivity of aryl chlorides, which from the standpoints of cost and availability are more attractive substrates than the corresponding bromides, iodides, and triflates. Traditional palladium/triarylphosphane catalysts are only effective for the coupling of certain activated aryl chlorides (for example, heteroaryl chlorides and substrates that bear electron-withdrawing groups), but not for aryl chlorides in general. Since 1998, major advances have been described by a number of research groups addressing this challenge; catalysts based on bulky, electron-rich phosphanes and carbenes have proved to be particularly mild and versatile. This review summarizes both the seminal early work and the exciting recent developments in the area of palladium-catalyzed couplings of aryl chlorides.
Ratio of Tensions from Vacuum String Field Theory

We show analytically that the ratio of the norm of sliver states agrees with the ratio of D-brane tensions. We find that the correct ratio appears as a twist anomaly.
Ion broadening of dense-plasma spectral lines including field-dependent atomic physics and the ion quadrupole interaction

We examine the theoretical line spectra from hydrogenlike argon in the electron-number-density range of ${10}^{24--}$${10}^{25}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$ and at a temperature corresponding to kT=800 eV. At these high densities it is important to address the relevance of higher-order plasma-ion microfield effects on the spectral line shape. We begin by calculating spectral line shapes using electric-field-dependent matrix elements that are constructed from wave functions which are solutions of Schr\"odinger's equation for hydrogenic ions in a uniform field. This provides a suitable basis for including microfield spatial nonuniformities by considering the quadrupole term in the radiator-perturbing ion interaction. Field gradients are calculated in an approximation that takes ion-ion correlations into account. We examine the consequences of these effects as well as of mixing between the adjacent Stark manifold on the Lyman-\ensuremath{\alpha} and Lyman-\ensuremath{\beta} lines of hydrogenlike argon.
Feedback from the First Supernovae in Protogalaxies: The Fate of the Generated Metals

We investigate the chemodynamic effects of multiple supernova (SN) explosions in the central region of primordial galaxies (e.g., M ~ 108 M☉ halo at z ~ 10) using three-dimensional hydrodynamic simulations of the inhomogenous interstellar medium down to parsec scales. We find that the final protogalactic structure and metal distribution depend strongly on the number of SNe. Specifically, 1000 SNe after an instantaneous burst of star formation are sufficient to almost completely blow away the gas in these systems, whereas 100 SN explosions trigger the collapse of the protogalactic cloud, leading to the formation of a cold, dense clumpy disk (n > 300 cm-3) with metallicity Z = 4 × 10-4 Z☉. These results imply that the metallicity of the "second generation" of stars could be Z ~ 10-4 Z☉, and that the environment to form metal-free stars in protogalaxies may be lost relatively quickly (107 yr) after the first burst of Z = 0 star formation. The recently discovered ultra-metal-poor star (Christlieb et al.) may represent surviving members of such second-generation star formation.
Chaos in turbulence driven by the magnetorotational instability

Chaotic flow is studied in a series of numerical magnetohydrodynamical simulations that use the shearing box formalism. This mimics important features of local accretion disc dynamics. The magnetorotational instability gives rise to flow turbulence, and quantitative chaos parameters, such as the largest Lyapunov exponent, can be measured. Linear growth rates appear in these exponents even when the flow is fully turbulent. The extreme sensitivity to initial conditions associated with chaotic flows has practical implications, the most important of which is that hundreds of orbital times are needed to extract a meaningful average for the stress. If the evolution time in a disc is less than this, the classical α formalism will break down.
Topological density and instantons on a lattice

We present an update on the study of topological structure of QCD. Issues addressed include a comparison between the plaquette and the geometric methods of calculating the topological density. We show that the improved gauge action based on 3 blocking transformation suppresses the formation of topologically charged dislocations with low action. Using a cooling method we identify the instantons' location, estimate their size and density, and calculate the renormalization constant ZQ for the plaquette method.
Time-dependent wave envelope finite difference analysis of sound propagation

A transient finite difference wave envelope formulation is presented for sound propagation, without steady flow. Before the finite difference equations are formulated, the governing wave equation is first transformed to a form whose solution tends not to oscillate along the propagation direction. This transformation reduces the required number of grid points by an order of magnitude. Physically, the transformed pressure represents the amplitude of the conventional sound wave. The derivation for the wave envelope transient wave equation and appropriate boundary conditions are presented as well as the difference equations and stability requirements. To illustrate the method, example solutions are presented for sound propagation in a straight hard wall duct and in a two dimensional straight soft wall duct. The numerical results are in good agreement with exact analytical results.
Low temperature deposition of tribological coatings

The results of microstructural and tribological studies performed on sputterdeposited coatings of ZrO2 20Y2O3, TiB2, and B18 wt pct Si are reported. In each case, deposition parameters were identified that offered good tribological properties while maintaining low deposition temperatures (< 400 °C) to avoid distortion and softening of prior heattreated substrates. Zirconia deposits were prepared with a pronounced columnar microstructure that provided excellent thermal fatigue and wear resistance, making them candidates for heat engine applications. The TiB2 coatings were the hardest coatings prepared. These provided good wear resistance on steel substrates. The BSi coating displayed excellent wear resistance and good adherence to Cu and Al alloys.
Hawaii Volcano Observatory 75th anniversary

The 75th anniversary of the founding of the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) was celebrated during January 1987. The festivities began on January 9 with the opening in Hilo of a major exhibit at the Wailoa Center on the current work of HVO, its history, and its special relationship to Hawaii Volcanoes National Park. In addition to spectacular photographs of volcanic activity and HVO field work, the exhibit featured continuous showings of underwater footage taken during the recent eruptive activity (December 1986) and a computer monitor that displayed the activity of HVO seismic net in real time. The exhibit, which was coordinated by HVO librarian/photo archivist Taeko Jane Takahashi and which featured the professional work of HVO photographer J . D. Griggs, was well received and will probably form the core of a future traveling exhibit.
The Elusive Safeguards of Federalism

The Supreme Court has issued a series of opinions that turn on the Constitution's inherent principles of federalism, decisions that have alarmed many a legal scholar. The Court has been attacked for overstepping its bounds and, by some, on the grounds that the federalism-state balance should be maintained through the political process rather than judicial review. This criticism of the judicial enforcement of federalism fails as a matter of constitutional history and on empirical grounds. The Supreme Court in this era deserves praise, not criticism, for its recent federalism jurisprudence.
Numerical optimization for symmetric tensor decomposition

We consider the problem of decomposing a real-valued symmetric tensor as the sum of outer products of real-valued vectors. Algebraic methods exist for computing complex-valued decompositions of symmetric tensors, but here we focus on real-valued decompositions, both unconstrained and nonnegative, for problems with low-rank structure. We discuss when solutions exist and how to formulate the mathematical program. Numerical results show the properties of the proposed formulations (including one that ignores symmetry) on a set of test problems and illustrate that these straightforward formulations can be effective even though the problem is nonconvex.
Nanostructured electrodes for high-performance pseudocapacitors.

The depletion of traditional energy resources as well as the desire to reduce high CO(2) emissions associated with energy production means that energy storage is now becoming more important than ever. New functional electrode materials are urgently needed for next-generation energy storage systems, such as supercapacitors or batteries, to meet the ever increasing demand for higher energy and power densities. Advances in nanotechnology are essential to meet those future challenges. It is critical to develop ways of synthesizing new nanomaterials with enhanced properties or combinations of properties to meet future challenges. In this Minireview we discuss several important recent studies in developing nanostructured pseudocapacitor electrodes, and summarize three major parameters that are the most important in determining the performance of electrode materials. A technique to optimize these parameters simultaneously and to achieve both high energy and power densities is also introduced.
Precise Structural Development and its Correlation to Function in Conjugated Polymer: Fullerene Thin Films by Controlled Solvent Annealing

The impact of controlled solvent vapor exposure on the morphology, structural evolution, and function of solvent-processed poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) bilayers is presented. Grazing incident wide angle X-ray scattering (GIWAXS) shows that the crystallization of P3HT increases with solvent exposure, while neutron reflectivity shows that P3HT simultaneously diffuses into PCBM, indicating that an initial bilayer structure evolves into a bulk heterojunction structure. Small angle neutron scattering (SANS) shows the agglomeration of PCBM and the formation of a PCBM pure phase when solvent annealing for 90 min. The structural evolution can be described as occurring in two stages: the first stage combines the enhanced crystallization of P3HT and diffusion of PCBM into P3HT, while the second stage entails the agglomeration of PCBM and formation of a PCBM pure phase. The phase separation of PCBM from P3HT is not driven by P3HT crystallinity, but is due to the concentration of PCBM exceeding the miscibility limit of PCBM in P3HT. Correlation of the morphology to photovoltaic activity shows that device performance significantly improves with solvent annealing for 90 min, indicating that both sufficient P3HT crystallization and formation of a PCBM pure phase are crucial in the optimization of the morphology of the active layer.
An information systems-centric curriculum, ISCC '99

Abstract This article describes a curriculum designed to prepare students to work with large systems, to take a systems view from the very beginning, and to develop collaborative and communications skills. The curriculum is a result of a mutually beneficial collaboration between university professors and representatives from business and industry. The curriculum builds an academically sound conceptual technical base for the student and focuses on the needs of the workplace. Student learning and faculty teaching paradigms were explored and were incorporated into the curriculum design. The resulting curriculum provides an educational experience that produces students prepared to meet the increasing needs of industry to create and use complex information systems and forms the basis for life-long learning.
Hyperbolic trapped rays and global existence of quasilinear wave equations

We prove global existence for quasilinear wave equations outside of a wide class of obstacles. The obstacles may contain trapped hyperbolic rays as long as there is local exponential energy decay for the associated linear wave equation. Thus, we can handle all non-trapping obstacles. We are also able to handle non-diagonal systems satisfying the appropriate null condition.
Peptide-targeted diagnostics and radiotherapeutics.

Radiotherapeutic drugs and medical imaging agents, although used for different purposes, both benefit from precise targeting. When systemically administered, either would be most useful if designed to find and bind only a tumor, single type of cell, or unique molecular assembly thereon. In this Account, we examine the use of small peptides, natural and synthetic, to create biochemically specific molecular imaging agents and radiotherapeutic pharmaceuticals, discussing three distinct examples. In one project, a small natural peptide known to target members of the bombesin family of receptors was chemically attached to a strong, versatile metal chelator, DO3A, through a series of small-molecule linkers. The linkers powerfully affected not only binding strength for the bombesin receptors, tissue distribution, and tumor uptake in vivo but also receptor subtype specificity. When the assembly is combined with an active metal ion for human trials, the versatility of the DO3A (dodecanetriacetate) chelate affords ...
Forecast combination and encompassing: Reconciling two divergent literatures

Abstract The relationship of forecast combination to recent developments in the theory and practice of model selection (in particular, the encompassing literature) is explored, the pragmatic virtues of forecast combination are argued, and a synthesis is attempted. Promising areas for future research, particularly exploration and development of forecast combination methodologies that facilitate ‘shrinkage’ of estimated combining weights toward a measure of central tendency, are also discussed.
Synthesis of Chiral Nitroxides and an Unusual Racemization Reaction.

Lai's protocol for the synthesis of nitroxides has been extended to the synthesis of several new chiral piperazine and morpholine nitroxides. This strategy utilizes the Bargellini reaction as the key bond-forming step. Several optically pure nitroxides incorporating α-aromatic and α-spiro centers were prepared by this route. These chiral nitroxides will be of interest as enantioselective oxidants, as traps for prochiral radicals, and in the preparation of new materials. One of these nitroxides, compound 43, was found to racemize under mild oxidizing conditions. The mechanism for this unusual racemization reaction was investigated.
Financing the emerging firm

This study explores the financing choices of 1,214 nascent entrepreneurs in the PSED II dataset. Funding sources are divided into two broad categories: personal and external. We develop a set of hypotheses about the kinds of firm and nascent entrepreneur characteristics that would likely influence which categories of financial resources are used, and the amounts acquired. The majority of financing (57% of all financing) for emerging ventures comes from the personal contributions of its founders, who contributed a median amount of $5,500 per respondent. Firms that more likely to acquire external funding were projected to have higher levels of revenue, were incorporated, and were legally registered. Nascent entrepreneurs with higher levels of education and net worth were significantly more likely to acquire external funding. Results from analyses are presented and discussed. Implications of our findings are provided and suggestions for future research are offered.
Inferring the Sign of Kinase-Substrate Interactions by Combining Quantitative Phosphoproteomics with a Literature-Based Mammalian Kinome Network

Protein phosphorylation is a reversible post-translational modification commonly used by cell signaling networks to transmit information about the extracellular environment into intracellular organelles for the regulation of the activity and sorting of proteins within the cell. For this study we reconstructed a literature-based mammalian kinase-substrate network from several online resources. The interactions within this directed graph network connect kinases to their substrates, through specific phosphosites including kinasekinase regulatory interactions. However, the “signs” of links, activation or inhibition of the substrate upon phosphorylation, within this network are mostly unknown. Here we show how we can infer the “signs” indirectly using data from quantitative phosphoproteomics experiments applied to mammalian cells combined with the literature-based kinase-substrate network. Our inference method was able to predict the sign for 321 links and 153 phosphosites on 120 kinases, resulting in signed and directed subnetwork of mammalian kinase-kinase interactions. Such an approach can rapidly advance the reconstruction of cell signaling pathways and networks regulating mammalian cells.
Hybrid unsupervised-supervised approach for computerized classification of malignant and benign masses on mammograms

A hybrid classifier which combines an unsupervised adaptive resonance network (ARTs) and a supervised linear discriminant classifier (LDA) was developed for analysis of mammographic masses. Initially the ART2 network separates the masses into different classes based on the similarity of the input feature vectors. The resulting classes are subsequently divided into two groups: (1) classes containing only malignant masses and (2) classes containing both malignant and benign or only benign masses. All masses belonging to the second group are used to formulate a single LDA model to classify them as malignant and benign. In this approach, the ART2 network identifies the highly suspicious malignant cases and removes them from a training set, thereby facilitating the formulation of the LDA model. In order to examine the utility of this approach, a data set of 348 regions of interest (ROIs) containing biopsy-proven masses (169 benign and 179 malignant) were used. Ten different partitions of training and test groups were randomly generated using 73% of ROIs for training and 27% for testing. Classifier design including feature selection and weight optimization was performed with the training group. The test group was kept independent of the training group. The performance of the hybrid classifier was compared to that of an LDA classifier alone. Receiver Operating Characteristics (ROC) analysis was used to evaluate the accuracy of the classifier. The average area under the ROC curve (Az) for the hybrid classifier was 0.81 as compared to 0.78 for LDA. The Az values for the partial areas above a true positive fraction of 0.9 were 0.34 and 0.27 for the hybrid and the LDA classifier, respectively. These results indicate that the hybrid classifier is a promising approach for improving the accuracy of classification in CAD applications.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Low-Luminosity Accretion in Black Hole X-Ray Binaries and Active Galactic Nuclei

At luminosities below a few percent of Eddington, accreting black holes switch to a hard spectral state which is very different from the soft blackbody-like spectral state that is found at higher luminosities. The hard state is well-described by a two-temperature, optically thin, geometrically thick, advection-dominated accretion flow (ADAF) in which the ions are extremely hot (up to 1012 K near the black hole), the electrons are also hot (∼109–10.5 K), and thermal Comptonization dominates the X-ray emission. The radiative efficiency of an ADAF decreases rapidly with decreasing mass accretion rate, becoming extremely low when a source reaches quiescence. ADAFs are expected to have strong outflows, which may explain why relativistic jets are often inferred from the radio emission of these sources. It has been suggested that most of the X-ray emission also comes from a jet, but this is less well established.
Q-Systems, Factorization Dynamics, and the Twist Automorphism

We provide a concrete realization of the cluster algebras associated with Q-systems as amalgamations of cluster structures on double Bruhat cells in simple algebraic groups. For nonsimply-laced groups, this provides a cluster-algebraic formulation of Q-systems of twisted type. It also yields a uniform proof of the discrete integrability of these Q-systems by identifying them with the dynamics of factorization mappings on quotients of double Bruhat cells. On the double Bruhat cell itself, we find these dynamics are closely related to those of the Fomin-Zelevinsky twist map. This leads to an explicit formula expressing twisted cluster variables as Laurent monomials in the untwisted cluster variables obtained from the corresponding mutation sequence. This holds for Coxeter double Bruhat cells in any symmetrizable Kac-Moody group, and we show that in affine type the analogous factorization mapping is also integrable.
A study of hydroboration of alkenes and alkynes with pinacolborane catalyzed by transition metals

Pinacolborane (PBH) is an excellent stoichiometric hydroboration reagent for alkenes and alkynes in the presence of catalytic amounts of transition metals. While Wilkinson's catalyst causes isomerization of internal alkenes, Rh(CO)(PPh3)2Cl gives the internal alkyl pinacolboronates in excellent regioselectivity. Rhodium and also nickel are extremely effective catalysts for the hydroboration of alkynes with PBH.
Gravitational Lensing of the Microwave Background by Galaxy Clusters

Galaxy clusters will distort the pattern of temperature anisotropies in the microwave background via gravitational lensing. We create lensed microwave background maps using clusters drawn from numerical cosmological simulations. A distinctive dipole-like temperature fluctuation pattern is formed aligned with the underlying microwave temperature gradient. For a massive cluster, the characteristic angular size of the temperature distortion is a few arcminutes, and the characteristic amplitude a few microkelvins. We demonstrate a simple technique for estimating the lensing deflection induced by the cluster; microwave background lensing measurements have the potential to determine the mass distribution for some clusters with good accuracy on angular scales up to a few arcminutes. Future high-resolution, high-sensitivity microwave background maps will have the capability of detecting lensing by clusters; we discuss various systematic limitations on probing cluster masses using this technique.
Nanoscale Stabilization of New Phases in the PbTe-Sb2Te3 System: PbmSb2nTem+3n Nanocrystals

A series of novel rock-salt-type PbmSb2nTem+3n nanocrystals (m = 2, 3, 4, 6, 8, and 10; n = 1 and 2) were successfully prepared using a colloidal synthesis route. These materials are stable only on the nanoscale and have no bulk analogues. Elemental compositions were determined using scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy (STEM/EDS) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The nanocrystals exhibit well-defined band energies in the mid-IR region that are nearly independent of their atomic compositions. PbmSb2nTem+3n nanocrystals behave as metastable homogeneous solid solutions at room temperature and tend to phase separate into the respective binary PbTe + Sb2Te3 at 300 °C. Furthermore, pair distribution function (PDF) analysis suggests that the local structure of these PbmSb2nTem+3n nanocrystals is distorted with respect to the rock-salt structure.
Tobramycin-EDTA conjugate : A noninnocent affinity-cleaving reagent

The design, synthesis, and ribozyme inhibitory activity of a novel EDTA-aminoglycoside conjugate are reported. This affinity cleaving reagent is a noninnocent RNA binder: its RNA affinity, judged by its ability to inhibit the hammerhead ribozyme HH16, is different than the parent natural product and is markedly dependent on the oxidation state of the chelated metal ion.
Causal geometry of Einstein-Vacuum spacetimes with finite curvature flux

One of the central difficulties of settling the L2-bounded curvature conjecture for the Einstein-Vacuum equations is to be able to control the causal structure of spacetimes with such limited regularity. In this paper we show how to circumvent this difficulty by showing that the geometry of null hypersurfaces of Enstein-Vacuum spacetimes can be controlled in terms of initial data and the total curvature flux through the hypersurface.
Cylindrical vector beam generation from a multi elliptical core optical fiber

A method for the generation of cylindrical vector beams based on the design of a multicore optical fiber is presented. This design consists of N elliptical cores symmetrically arranged in a circular array about the fiber axis, where the orientation of each core's major axes has an azimuthally varying distribution. A cylindrically symmetric amplitude and polarization state is produced in the far field of the fiber output by the coherent superposition of the individual core outputs. Such a fiber with N=6 cores is fabricated and experimentally investigated. Numerical simulations show the dependence of the far field intensity of an array of Gaussian beamlets on the number of beamlets and their spacing in the array.
Existence and blow up of small-amplitude nonlinear waves with a sign-changing potential

Abstract We study the nonlinear wave equation with a sign-changing potential in any space dimension. If the potential is small and rapidly decaying, then the existence of small-amplitude solutions is driven by the nonlinear term. If the potential induces growth in the linearized problem, however, solutions that start out small may blow-up in finite time.
Bounds for Kakeya-type maximal operators associated with $k$-planes

A $(d,k)$ set is a subset of $\rea^d$ containing a translate of every $k$-dimensional plane. Bourgain showed that for $k \geq \kcrit(d)$, where $\kcrit(d)$ solves $2^{\kcrit-1}+\kcrit = d$, every $(d,k)$ set has positive Lebesgue measure. We give a short proof of this result which allows for an improved $L^p$ estimate of the corresponding maximal operator, and which demonstrates that a lower value of $\kcrit$ could be obtained if improved mixed-norm estimates for the $x$-ray transform were known.
Lariat Ether Carboxylic Acids, O-Benzylhydroxamates and Hydroxamic Acids with Fluorinated Substituents: Synthesis, Metal Ion Complexation and Solubility in Supercritical Carbon Dioxide

Abstract A series of lariat ether carboxylic acids, O-benzylhydroxamates, and hydroxamic acids with fluorine-containing substituents is prepared. In general, the presence of fluorine-containing substituents is found to increase the solubility of the lariat ethers in supercritical carbon dioxide. Efficiencies of the fluorine-containing lariat ether carboxylic and hydroxamic acids are compared with those for non-fluorinated analogs in solvent extraction of lanthanide ions from aqueous solutions into chloroform. Responses of the fluorine-containing lariat ether O-benzylhydroxamates towards alkali metal cations in solvent polymeric membrane electrodes are compared with those analogous non-fluorinated compounds.