cssi/SciSciGPT-SciSciNet huggingface dataset:
New Thermal Routes to ortho-Benzyne

There is experimental evidence that intermediate ortho-benzynes can be made by intramolecular [2 + 4] cycloaddition of a 1,3-diyne with an alkyne. Computations by several groups support a concerted mechanism for the cycloaddition of butadiyne with acetylene. High temperature benzyne cycloreversion has also been demonstrated experimentally; this may in fact be a common reaction in hydrocarbon fuel combustion. Following leads from earlier pyrolysis experiments, herein we predict that cycloaddition of benzyne with butadiyne can proceed by a stepwise mechanism to 2,3-naphthyne. However, a slightly lower energy path leads to a benzocyclobutadiene. ortho-Benzyne can be generated by solution-phase and solid-phase reaction in a microwave reactor. We have developed the method of microwave flash pyrolysis (MFP) for high temperature solid-phase microwave reactions. MFP reaction of phthalic anhydride, a classic benzyne precursor, results in a typical suite of products expected from a relatively high concentration of benzyne.
Is Double Reionization Physically Plausible

Recent observations of z ~ 6 quasars and the cosmic microwave background imply a complex history of cosmic reionization. Such a history requires some form of feedback to extend reionization over a long time interval, but the nature of the feedback and how rapidly it operates remain highly uncertain. Here we focus on one aspect of this complexity: which physical processes can cause the global ionized fraction to evolve nonmonotonically with cosmic time? We consider a range of mechanisms and conclude that double reionization is much less likely than a long, but still monotonic, ionization history. We first examine how galactic winds affect the transition from metal-free to normal star formation. Because the transition is actually spatially inhomogeneous and temporally extended, this mechanism cannot be responsible for double reionization, given plausible parameters for the winds. We next consider photoheating, which causes the cosmological Jeans mass to increase in ionized regions and hence suppresses galaxy formation there. In this case, double reionization requires that small halos form stars efficiently, that the suppression from photoheating is strong relative to current expectations, and that ionizing photons are preferentially produced outside previously ionized regions. Finally, we consider H2 photodissociation, in which the buildup of a soft ultraviolet background suppresses star formation in small halos. This can in principle cause the ionized fraction to temporarily decrease, but only during the earliest stages of reionization. Finally, we briefly consider the effects of some of these feedback mechanisms on the topology of reionization.
Optimal choice of monetary policy instruments under velocity and fiscal shocks

Abstract This paper, in the spirit of Poole [Poole, William, 1970. The Optimal Choice of Monetary Policy Instruments in a Simple Macro Model. Quarterly Journal of Economics, 84, 192–216.], studies how differently monetary and fiscal shocks influence the appropriate choice of the monetary policy regime. Velocity shocks are introduced by embedding a stochastic cash-in-advance constraint within the New Keynesian framework. In addition to optimal policy under discretion, three classic rules, interest rate targeting, monetary targeting, and the Taylor rule are ranked under both fiscal and velocity shocks. The non-stationarity of prices under the Taylor rule makes it inferior to the other rules under which prices are stationary. Monetary targeting, by stabilizing aggregate demand under fiscal shocks, outperforms interest rate targeting, while the latter provides a better insulation against velocity shocks. Monetary targeting (under fiscal shocks) and interest rate targeting (under velocity shocks) even outperform the optimal policy under discretion for sufficiently high intertemporal elasticities of consumption substitution.
The significance of transient ischemic dilation in the setting of otherwise normal SPECT radionuclide myocardial perfusion images

Transient ischemic dilation (TID) in the setting of an abnormal SPECT radionuclide myocardial perfusion imaging (MPI) study is considered a marker of severe and extensive coronary artery disease (CAD). However, the clinical significance of TID and its association with CAD in patients with an otherwise normal MPI study is unclear. From a database of patients who underwent MPI over a 9-year period, 96 without known cardiac history who had normal image perfusion patterns, and who underwent coronary angiography within 6 months, were identified. TID quantitative values were derived. To adjust for varying stress and image protocols, a TID index based on published threshold values was derived for each patient, with >1 considered as TID. We examined the relationship of TID to the presence/extent of CAD, and to a CAD prognostic index. TID was also correlated with patient survival. To address referral bias, survival in a separate cohort of 3,691 patients with a normal perfusion MPI who did not undergo angiography in the 6-month interval was correlated with the presence and severity of TID. For 28 (29.2%) patients with normal MPI perfusion patterns but with TID, there was no increased incidence of CAD, multivessel or left main disease, or a higher prognostic index compared with no TID. In addition, there was no increased mortality associated with TID in both the angiography cohort and in the patients who did not undergo immediate angiography. TID in patients with an otherwise normal SPECT MPI study does not increase the likelihood of CAD, its extent or severity, and is not associated with worsened patient survival.
Inductive learning of relational productions

Relational productions provide a mathematically tractable formal model for operators in discrete systems. Two paradigms for the inductive learning of such operators are considered: before-and-after situation pairs and situation sequences. An operational theory for the generalization of productions for these paradigms is then developed, based on previous work in concept induction. This theory has been computer implemented. In examples three "blocks world" operators are learned from six before-and-after pairs and also from a sequence of fifteen blocks world situations. A transformational grammar learning example of Hayes-Roth is repeated with an improvement in speed of two orders of magnitude.
Development of the CoMac Adherence Descriptor™: a linguistically-based survey for segmenting patients on their worldviews.

Nonadherence to prescribed medication and healthy behaviors is a pressing health care issue. Much research has been conducted in this area under a variety of labels, such as compliance, disease management and, most recently, adherence. However, the complex factors related to predicting and, more importantly, understanding and explaining adherence, have nevertheless remained elusive. However, through an in-depth linguistic analysis of patient talk, the International Center for Intercultural Communication (ICIC) at Indiana University has produced a psycholinguistic coding system that uses patients’ own language to cluster them into distinct groups based on their worldviews. ICIC’s studies have shown, for example, that patients reveal their fundamental perceptions about themselves and their environment in their life narratives; clustering of individual patients based on these different perceptions is possible via the use of differential language in survey questions, and differential language can be used to tailor messages for individual patients in a manner that these individuals prefer over generically worded communication. In grant-funded research, an interdisciplinary team of researchers at the ICIC reviewed the literature and identified three basic psychosocial tenets related to adherence: control orientation, based on locus of control research; agency, based on self-efficacy; and affect or attitude and emotion. These three constructs were selected because, in the published literature, they have been consistently found to be connected to patient adherence. Based on this research, a survey, the CoMac Descriptor™ was developed. This report shows that The Descriptor™ questions and responses are valid and reliable in segmenting patients across psychosocial constructs, which will have positive implications for health care providers and patients.
The lefthanded local lemma characterizes chordal dependency graphs

Shearer gave a general theorem characterizing the family \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\mathcal{L}$\end{document} **image** of dependency graphs labeled with probabilities pv which have the property that for any family of events with a dependency graph from \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\mathcal{L}$\end{document} **image** (whose vertex-labels are upper bounds on the probabilities of the events), there is a positive probability that none of the events from the family occur. We show that, unlike the standard Lovasz Local Lemma—which is less powerful than Shearer's condition on every nonempty graph—a recently proved ‘Lefthanded’ version of the Local Lemma is equivalent to Shearer's condition for all chordal graphs. This also leads to a simple and efficient algorithm to check whether a given labeled chordal graph is in \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$\mathcal{L}$\end{document} **image** . © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2012 © 2012 Wiley Periodicals, Inc.
Dynamic Stress Behavior in Catalytic Combustors

Dynamic stress behavior during catalytic combustion of methane has been simulated under transient warm-up, cool-down, and cyclic conditions. The numerical model combines a two-dimensional solution to the transport equations, solution of an energy balance on the monolith wall, and the NIKE3D structural analysis code to predict thermal stresses. The model also includes a detailed heterogeneous kinetics model for a proprietary palladium oxide (PdO) catalyst, but the model ignores gas-phase reactions. Results illustrate that thermal stresses as high as 630 MPa can form during transient operating modes, which risks structural failure of the ceramic monolith. The maximum computed thermal stress concentrations occur near the inlet of the monolith. Peak transverse stresses (which act to form axial cracks) typically form near the inlet and centerline of the monolith structure, while peak axial stresses form near the edges of the flat plate that represents the monolith structure. Increasing the preheat temperature of the incoming fuel and air mixture lessens the peak thermal stress. To a first approximation, the magnitude of the peak transverse stress during any transient cycle considered with our model can be estimated from the maximum value of the gradient in the computed temperature profiles.
Separation of time scales in aircraft trajectory optimization

Two methods for analyzing the time-scale properties of aircraft trajectory optimization problems are presented. Time-scale properties must be identified before solutions can be obtained by using singular perturbation methods. Both methods only require a knowledge of the state equations, the aircraft characteristics, and the bounds on the state and control variables. Although these methods give only rough estimates of time-scale separation, they do not require that an 'exact' optimal trajectory be known, as do the more rigorous methods, and they are an improvement on the ad hoc methods currently in use. The two methods are applied to an example problem for a high performance aircraft.
Strong Aharonov-Bohm oscillations in GaAs two-dimensional holes

The authors measured Aharonov-Bohm resistance oscillations [Phys. Rev. 115, 485 (1959)] in a shallow two-dimensional GaAs hole ring structure, defined by local anodic surface oxidation. The amplitude of the oscillations is about 10% of the ring resistance, the strongest seen in a hole system. In addition the authors observe resistance oscillations as a function of front gate bias at zero magnetic field. They authors discuss the results in light of spin interference in the ring and possible applications to spintronics.
General and Expedient Synthesis of 1,4-Dioxygenated Xanthones

A facile entry to 1,4-dioxygenated xanthones having a variety of substitution patterns and substituents was developed that features a novel application of the Moore cyclization using substrates that were readily assembled in a highly convergent fashion by an acetylide stitching process. The practical utility of the methodology was demonstrated by an efficient synthesis of a naturally occurring xanthone and correction of the structure of dulcisxanthone C.
Determining growth and yield limiting factors in potato from canopy spectral reflectance

Irrigated potato production in sandy soils can be impacted by low nitrogen (N) and water retention in the soil. A field study was conducted to use canopy spectral reflectance as a primary means to characterize N fertilizer rates and soil texture variations as growth and yield limiting factors in potato. A hand-held 16-band spectral radiometer was used to obtain reflectance readings of the potato canopies. Reflectance measurements were made in field plots that received four rates of N or in four areas where the soil textures were different. At later stages of plant growth, canopy reflectance in the 760 to 1000 nm spectral range was consistently higher in plots that received higher rates of N or in areas where the soil contained higher clay and silt fractions. Russet Burbank potatoes, with increasing rate of N fertilizer, showed a decreasing trend in total tuber yield and an increasing trend in percent of tubers with weight exceeding 170 g. Canopy reflectance was inversely related to tuber yield or size for Russet Burbank potatoes when soil texture was the only variable.
On the singularity index and the unfolding of the diffraction catastrophes

Abstract The caustics of high-frequency wave propagation may be classified using catastrophe theory. The wavefield in the vicinity of any caustic is described by the corresponding diffraction catastrophe. The singularity index, β, is a measure of the rate at which such a wavefield diverges as ω→∞ at the point where all control parameters and moduli are set equal to zero. It is shown that away from this point β also describes a balance between two different measures of the unfolding of the wavefield in each control direction, β = σnϱn. The indices σn and ϱn describe, respectively, the rate at which individual ray arrivals separate in time and decay as a function of control parameter.
Evidence for Accretion: High-Resolution X-Ray Spectroscopy of the Classical T Tauri Star TW Hydrae

We present high-resolution X-ray spectra of the X-ray-bright classical T Tauri star, TW Hydrae, covering the wavelength range of 1.5-25 A. The differential emission measure derived from fluxes of temperature-sensitive emission lines shows a plasma with a sharply peaked temperature distribution, peaking at log T = 6.5. Abundance anomalies are apparent, with iron very deficient relative to oxygen, while neon is enhanced relative to oxygen. Density-sensitive line ratios of Ne IX and O VII indicate densities near log ne = 13. A flare with rapid (~1 ks) rise time was detected during our 48 ks observation; however, based on analysis of the emission-line spectrum during quiescent and flaring states, the derived plasma parameters do not seem strongly time-dependent. The inferred plasma temperature distribution and densities are consistent with a model in which the bulk of the X-ray emission from TW Hya is generated via mass accretion from its circumstellar disk. Assuming that accretion powers the X-ray emission, our results for log ne suggest an accretion rate of ~10-8 M☉ yr-1.
Regulatory Dissonance and Challenges to Globalization: A Comparative Study of the United States and Indian Non-life Insurance Regulatory Frameworks

Regulatory dissonance not only poses serious challenges to insurance companies seeking global expansion, but also reiterates the fact that business models cannot be exported in their entirety from one country to another. This paper presents the regulatory dissonance that exists between the non-life insurance industry in the U.S. and India. It attempts to highlight the regulatory dissonance that exists in the business line definition area, accounting treatment of acquisition expenses, treatment of unearned premiums, creation of a catastrophe reserve, reinsurance cession, investment regulation, obligations to the rural and social sector, rate and form regulation and solvency margin computation. While the paper attempts to compare most of the dissonance that exists between the two regulatory frameworks, it does not purport to be an exhaustive study of all the discrepancies that exist between the two systems.
The genus of a random chord diagram is asymptotically normal

Let G"n be the genus of a two-dimensional surface obtained by gluing, uniformly at random, the sides of an n-gon. Recently Linial and Nowik proved, via an enumerational formula due to Harer and Zagier, that the expected value of G"n is asymptotic to (n-logn)/2 for n->~. We prove a local limit theorem for the distribution of G"n, which implies that G"n is asymptotically Gaussian, with mean (n-logn)/2 and variance (logn)/4.
Symmetrization of Bernoulli

We show that an asymmetric Bernoulli random variable is symmetry resistant in the sense that any independent random variable, which when added to it produces a symmetric sum, must have a variance at least as much as itself. The main instrument is to use Skorokhod embedding to transfer the discrete problem to the realm of stochastic calculus.
Seniority and anti-competitive restrictions on the legislative common pool: tenure’s impact on the overall production of legislation and the concentration of political benefits

It is well established that geographic areas benefit, in terms of the share of government spending they capture, from having a legislator with longer tenure, holding constant the tenure of other legislators. However, the implications of this literature for how the total production of legislation changes if all members gained seniority is less clear. Increased levels and dispersion of seniority within Congress generate a cartel-like effect, whereby legislators restrict the quantity of legislation enacted and increase the average price of each passed bill. The analysis provides a natural experiment to gauge the impacts of the emergence of the congressional committee system.
Control Allocation and Zero Dynamics

Closed-loop stability for dynamic inversion controllers depends on the stability of the zero dynamics. The zero dynamics, however, depend on a generally nonlinear control allocation function that optimally distributes redundant controls. Therefore, closed-loop stability depends on the control allocation function. A sufe cient condition is provided for globally asymptotically stable zero dynamics with a class of admissible nonlinear control allocation functions. It is shown that many common control allocation functions belong to the class of functions that are covered by the aforementioned zero dynamics stability condition. Aircraft e ight control examples are given to demonstrate the utility of the results.
Modeling self-deception within a decision-theoretic framework

Computational modeling of human belief maintenance and decision-making processes has become increasingly important for a wide range of applications. In this paper, we present a framework for modeling the human capacity for self-deception from a decision-theoretic perspective in which we describe an integrated process of wishful thinking which includes the determination of a desired belief state, the biasing of internal beliefs towards or away from this desired belief state, and the final decision-making process. Finally, we show that in certain situations self-deception can be beneficial.
The Advantage of Increased Resolution in the Study of Quasar Absorption Systems

We compare a new R = 120,000 spectrum of PG 1634+706 (zQSO = 1.337 and mV = 14.9) obtained with the HDS instrument on Subaru to a R = 45,000 spectrum obtained previously with the Keck HIRES. In the strong Mg II system at z = 0.9902 and the multiple-cloud, weak Mg II system at z = 1.0414, we find that at the higher resolution, additional components are resolved in a blended profile. We find that two single-cloud, weak Mg II absorbers were already resolved at R = 45,000, with b = 2-4 km s-1. The narrowest line that we measure in the R = 120,000 spectrum is a component of the Galactic Na I absorption, with b = 0.90 ± 0.20 km s-1. We discuss expectations of similarly narrow lines in various applications, including studies of damped Lyα absorbers, the Mg I phases of strong Mg II absorbers, and high-velocity clouds. By applying Voigt profile fitting to synthetic lines, we compare the consistency with which line profile parameters can be accurately recovered at R = 45,000 and 120,000. We estimate the improvement gained from superhigh resolution in resolving narrowly separated velocity components in absorption profiles. We also explore the influence of isotope line shifts and hyperfine splitting in measurements of line profile parameters, and the spectral resolution needed to identify these effects. Superhigh-resolution spectra of quasars, which will be routinely possible with 20 m class telescopes, will lead to greater sensitivity for absorption-line surveys, and to the determination of more accurate physical conditions for cold phases of gas in various environments.
Synthesis of Electronically Diverse Tetraarylimidazolylidene Carbenes via Catalytic Aldimine Coupling

A new method for synthesizing symmetrical N-heterocyclic imidazolium salts is described. Catalytic coupling of aldimines with cyanide followed by oxidation gives alpha-diketimines, which can then be cyclized with formaldehyde in acidic media. This two-step procedure requires no chromatography and allows the synthesis of electronically diverse 1,3,4,5-tetraarylimidazolylidene carbenes.
Real-time 3D visualization of volumetric video motion sensor data

This paper addresses the problem of improving detection, assessment, and response capabilities of security systems. Our approach combines two state-of-the-art technologies: volumetric video motion detection (VVMD) and virtual reality (VR). This work capitalizes on the ability of VVMD technology to provide 3D information about the position, shape, and size of intruders within a protected volume. The 3D information is obtained by fusing motion detection data from multiple video sensors. Other benefits include low nuisance alarm rates, increased resistance to tampering, low-bandwidth requirements for sending detection data to a remote monitoring site, and the ability to perform well in a dynamic environment where human activity and motion clutter are commonplace. The second component of this work involves the application of VR technology to display information relating to the sensors and the sensor environment. VR technology enables an operator, or security guard, to be immersed in a 3D graphical representation of the remote site containing the video sensors. VVMD data is transmitted from the remote site via ordinary telephone lines and displayed in real-time within the virtual environment. There are several benefits to displaying VVMD information in this way. Often, raw sensor information is not in a form that can be easily interpreted and understood--especially when taken out of the context of the sensor environment. Because the VVMD system provides 3D information and because the sensor environment is a physical 3D space, it seems natural to display this information in 3D. Also, the 3D graphical representation depicts essential details within and around the protected volume in a natural way for human perception. Sensor information can also be more easily interpreted when the operator can `move' through the virtual environment and explore the relationships between the sensor data, objects and other visual cues present in the visual environment. By exploiting the powerful ability of humans to understand and interpret 3D information, we expect to (1) improve the means for visualizing and interpreting sensor information, (2) allow a human operator to assess a potential threat more quickly and accurately, and (3) enable a more effective response. This paper will detail both the VVMD and VR technologies and will discuss a prototype system based upon their integration.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Triangular matrix coalgebras and applications

We formally introduce and study generalized comatrix coalgebras and upper triangular comatrix coalgebras, which are not only a dualization but also an extension of classical generalized matrix algebras. We use these to answer several open questions on Noetherian and Artinian type notions in the theory of coalgebras, and to give complete connections between these. We also solve completely the so called finite splitting problem for coalgebras: we show that is a coalgebra such that the rational part of every left finitely generated -module splits off if and only if is an upper triangular matrix coalgebra, for a serial coalgebra whose Ext-quiver is a finite union of cycles, a finite dimensional coalgebra and a finite dimensional bicomodule .
Government’s credible commitment in economic policy-making: Evidence from Singapore

Studies of participatory policy-making show citizens’ participation in policy-making yield better solutions and more successful policy performance. But studies of the Asian Newly Industrialized Countries (NICs) of South Korea, Singapore and Taiwan attribute the successful economic policies and performance of these NICs to strong governments that limit citizens’ participation or ignore their policy preferences. Are the Asian-NICs unique? This paper examines Singapore between the 1960s and 1990s to show empirically that, contrary to findings in Asian studies, the government bargains by credibly committing to include and realize private sector input. This government bargaining through credible commitment alleviates production investors’ concerns that government may arbitrarily set policies or even seize property. The government’s bargaining conforms to the following pattern: When the economy performs optimally, the government does nothing; however, when it is less-than-optimal, the government compensates production investors or demotes or replaces its representatives or agents, and increases private sector participation in monitoring, evaluation or modification of the government’s policies. This evidence of government bargaining advances existing scholarship in important ways. First, it provides a theoretical framework to understand if, how, and when government bargains with resource owners in the less-democratic NICs. In particular, the framework reveals how government bargaining may be credible despite the lack of formal constraints in these countries. Second, it shows that policy success in the Asian-NICs is the result of government bargaining with resource owners and not the result of limiting participation. This credible commitments argument, then, provides a new perspective on policy success in the NICs.
Single feed beam-steering of short pulses via time-reversal

In this presentation, we introduce a new approach to beam-steering of short, ultrawideband (UWB) pulses using a single-feed radiating structure. With a radiator consisting of small apertures backed by a reverberating cavity (Fig.1), a time-reversal (TR) technique is applied to generate a short pulse at each aperture with the corresponding time-delay for beamforming at a desired steering angle.
Guaranteed-Quality All-Quadrilateral Mesh Generation with Feature Preservation

In this paper, a quadtree-based mesh generation method is described to create guaranteed-quality, geometry-adapted all-quadrilateral meshes with feature preservation for arbitrary planar domains. Given point cloud, our method generates all-quad meshes with these points as vertices and all the angles are within [45°, 135°]. For given planar curves, quadtree-based spatial decomposition is governed by the curvature of the boundaries and narrow regions. 2-refinement templates are chosen for local mesh refinement without creating any hanging nodes. A buffer zone is created by removing elements around the boundary. To guarantee the mesh quality, the angles facing the boundary are improved via template implementation, and two buffer layers are inserted in the buffer zone. It is proved that all the elements of the final mesh are quads with angles between 45°±e and 135°±e (e ≤ 5°) with the exception of badly shaped elements that may be required by the specified geometry. Sharp features and narrow regions are detected and preserved. Furthermore, boundary layer meshes are generated by splitting elements of the second buffer layer. We have applied our algorithm to a set of complicated geometries, including the Lake Superior map and the air foil with multiple components.
Enantioselective Alkynylation of Aldehydes with 1-Haloalkynes Catalyzed by Tethered Bis(8-quinolinato) Chromium Complex

The first example of Cr-catalyzed asymmetric alkynylation of aldehydes with 1-iodo- and 1-bromoalkynes was developed. The use of tethered bis(8-quinolinato) chromium catalyst (3 mol %) allowed preparation of enantioenriched propargyl alcohols with good yields and enantioselectivities up to 92% ee. 1-Bromoalkynes can be activated by the introduction of a cobalt porphine co-catalyst, which enables shorter reaction times without any loss of enantiocontrol.
Characteristics of the crop-paulownia system in China

Abstract This paper reviews the crop-paulownia ( Paulownia elongata ) system in China. We focus on the system's characteristics and the impact of government policies on its development. When paulownia is intercropped with winter wheat, their different growth periods and root distributions result in more efficient use of water and other limited resources. In addition to timber production, paulownia trees on cropland enhance the microclimate and therefore improve wheat yield and quality. Intercropping also stabilizes farm income and reduces farm risk by diversifying agricultural activities and providing windbreaks and shelters that stabilize crop production over time. China's rural reform initiated in 1978 is a major source of the rapid development of the system in the past decade. Reports of the good performance of the crop-paulownia system, along with its high tolerance to natural conditions, are likely to make it attractive to other countries.
The San Andreas fault experiment

Abstract Two NASA laser satellite tracking systems on opposite sides of the San Andreas fault will be used in an experiment to measure the gross relative motion of the tectonic plates of North America and the Pacific during the next several years. Initial sites at San Diego on the Pacific Plate and Quincy, California, on the North American Plate, nearly 900 km apart, have already been selected and occupied, and other sites further south are proposed. Each site is occupied for two or three months per year and simultaneous precision laser distance measurements to the Beacon Explorer-C satellite from these sites will be used to determine the relative position of one site with respect to the other. Results of a simulation of this experiment in which a pair of sites are reoccupied annually for about eight years indicate an eventual accuracy of about 0.5 cm/yr in the average plate motion. The results of a preliminary three-month observing period in 1972 indicate a precision of about 15 cm in the chord distance between the San Diego and Quincy sites.
Solvability of the Generalized Possio Equation in 2D Subsonic Aeroelasticity

We study solvability of the generalized Possio integral equation which is a tool in the analysis of a boundary value problem in 2D subsonic aeroelasticity with the Kutta-Joukowski condition — “zero pressure discontinuity” — ψ(x, 0, t) = 0 on the complement of a finite interval in the entire real line ℝ. The corresponding problem with boundary condition on finite intervals adjacent to the “chord” was considered in [16].
Straight time and overtime in equilibrium

Abstract We formulate an equilibrium model of straight time and overtime wages by imposing restrictions on agents' consumption sets and using a commodity space that includes employment lotteries. We extract some time series implications from a linear-quadratic approximation to our model evaluated at particular parameter values. We use our model informally to interpret some features of observed time series for wages and employment.
Total Synthesis of Gambierol: The Generation of the A-C and F-H Subunits by Using a C-Glycoside Centered Strategy

Gambierol, a representative of the marine ladder toxin family, consists of eight ether rings, 18 stereocenters, and two challenging pyranyl rings having methyl groups that are in a 1,3-diaxial orientation to one another. Herein we describe the generation of gambierol's A-C and F-H ring systems and demonstrate the versatility of the glycosyl anhydride, enol ether-olefin RCM strategy to fused polycyclic ethers. This work has both enabled us to generate sufficient quantities of the gambierol precursors and has enabled us to better understand the chemical transformations that were key to these efforts. Fundamental work included efforts to C-glycosides and C-ketosides, Claisen rearrangements, and enol ether-olefin RCM reactions.
Compression of SAR imagery using adaptive residual vector quantization

Compression of SAR imagery for battlefield digitization is discussed in this paper. THe images are first processed to separate out possible target areas. These target areas are compressed losslessly to avoid any degradation of the images. The background information which is usually necessary to establish context, is compressed using a hybrid vector quantization algorithm. An adaptive variable rate residual vector quantizer is use to compress the residual signal generated by a neural network predictor. The vector quantizer codebooks are optimized for entropy coding using an entropy-constrained algorithm to further improve the coding performance. This constrained vector-quantizer combination performs extremely well as suggested by the experimental results.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Exact-image method for Gaussian-beam problems involving a planar interface

The exact-image method, recently introduced for the solution of electromagnetic field problems involving sources above a planar interface between two homogeneous media, is shown to be valid also for sources located in complex space, which makes its application possible for Gaussian-beam analysis. It is demonstrated that the Goos-Hanchen shift and the angular shift of a TE-polarized beam are correctly given as asymptotic results by the exact-reflection-image theory. Also, the apparent-image location giving the correct Gaussian beam transmitted through the interface is obtained as another asymptotic check. The theory described here makes it possible to calculate the exact coupling from the Gaussian beam to the reflected and refracted beams as well as to the surface wave.
Total synthesis of (-)-ascochlorin via a cyclobutenone-based benzannulation strategy.

The application of a convergent benzannulation strategy in an efficient synthesis of (−)-ascochlorin is described.
Synthetic Studies of the Cororubicin Oligosaccharide: Glycosylation of Branched Amino and Nitro Sugars

Abstract Derivatives of the branched amino sugar methyl 3-amino-2,3,6-trideoxy-3-C-methyl-α-L-ribo-hexopyranoside and its 3-nitro analog were coupled with glycosyl donors of 3,4-di-O-acetyl-2,6-dideoxy-L-fucopyranose. Successful glycosylations were developed using the fucosyl bromide, activated with silver triflate, and the fucosyl oxysilane, activated with trimethylsilyl triflate. High stereoselectivities for the desired α-1,4 linkage were observed in both cases. The N-trifluoroacetamido disaccharide was deacylated and the amino group oxidized to nitro with dimethyldioxirane. An alternate route based on coupling of the fucosyl bromide with the nitro sugar methyl α-L-decilonitroside also gave the α-linked disaccharide, which is related to oligosaccharides found in the antibiotics cororubicin and arugomycin.
Indirect probes of the MSSM after the Higgs discovery

We study the minimal supersymmetric standard model (MSSM) with minimal flavor violation (MFV), imposing constraints from flavor physics observables and MSSM Higgs searches, in light of the recent discovery of a 125 GeV Higgs boson by ATLAS and CMS. We analyze the electroweak vacuum stability conditions to further restrict the MSSM parameter space. In addition, a connection to ultraviolet physics is shown via an implementation of renormalization group running, which determines the TeV-scale spectrum from a small set of minimal supergravity parameters. Finally, we investigate the impact from dark matter direct detection searches. Our work highlights the complementarity of collider, flavor and dark matter probes in exploring the MSSM, and shows that even in a MFV framework, flavor observables constrain the MSSM parameter space well beyond the current reach of direct SUSY particle searches.
Complementary regioselective cyclopropyl ring openings of 6-formyl-spirobicyclo[5.2]octane mediated by TMSCl and TBAI

Abstract Absolute control over the regioselectivity of trimethylsilyl halide-induced cyclopropane fragmentation of a spirofused cyclopropyl carboxaldehyde has been achieved by simply varying the reaction stoichiometry and the nature of the halide. Treatment of 6-formyl-spirobicyclo[5.2]octane with a large excess of TMSCl gave 3-(1-chlorocyclohexyl)propanal (84% yield), whereas 2-(1-iodomethylcyclohexyl)ethanal (86% yield) was obtained using 10 equivalents each TMSCl and n -Bu 4 NI (TBAI). Use of only a moderate excess of TMSCl or TMSCl and TBAI gave the rearranged product 3-(1-cyclohexenyl)-propanal.
The abundance of interstellar nitrogen

Using the Hubble Space Telescope Goddard High Resolution Spectrograph (GHRS), we have obtained high S/N echelle observations of the weak interstellar N I λλ1160, 1161 absorption doublet toward the stars γ Cas, λ Ori, ι Ori, κ Ori, δ Sco, and κ Sco. In combination with a previous GHRS measurement of N I toward ζ Oph, these new observations yield a mean interstellar gas-phase nitrogen abundance (per 106 H atoms) of 106 N/H = 75 ± 4 (±1 σ). There are no statistically significant variations in the measured N abundances from sight line to sight line and no evidence of density-dependent nitrogen depletion from the gas phase. Since N is not expected to be depleted much into dust grains in these diffuse sight lines, its gas-phase abundance should reflect the total interstellar abundance. Consequently, the GHRS observations imply that the abundance of interstellar nitrogen (gas plus grains) in the local Milky Way is about 80% of the solar system value of 106 N/H = 93 ± 16. Although this interstellar abundance deficit is somewhat less than that recently found for oxygen and krypton with GHRS, the solar N abundance and the N I oscillator strengths are too uncertain to rule out definitively either a solar ISM N abundance or a solar ISM N abundance similar to that of O and Kr.
On combating the abuse of state secrecy

THERE is a cartoon by Herbert Block, the legendary cartoonist of The Washington Post, which features two worried-looking officials seated at a desk. Holding up a file, one official says to the other: “Well, we certainly botched this job. What’ll we stamp it—secret or top secret?” If Block’s cartoon summarizes the concern that state secrecy can be used to hide evidence of wrongdoing, past and present events remind us that state secrecy can also be used to justify the scope and substance of controversial policies. As Daniel Ellsberg, the main protagonist in the Pentagon Papers episode, has recently reminded us, history shows that:
Equivariant differential characters and symplectic reduction

We describe equivariant differential characters (classifying equivariant circle bundles with connections), their prequantization, and reduction.
Evaluation of a world wide web-based graduate social work research methods course

SUMMARY This paper reports on the evaluation of a world-wide-web-based social work research methods course in experimental design. The course was taught entirely on the Internet, with no meetings on campus. The same instructor taught another section of the same course during the same semester on campus. Descriptive process data and comparative student outcome data (grades and satisfaction) are presented. Recommendations are made for others considering such courses.
Recent results from measurements of the energy spectrum of cosmic-ray induced neutrons aboard an ER-2 airplane and on the ground

Abstract Crews of future high-altitude commercial aircraft may be significantly exposed to atmospheric cosmic radiation from galactic cosmic rays (GCR). To help determine such exposures, the Atmospheric Ionizing Radiation Project, an international collaboration of 15 laboratories, made simultaneous radiation measurements with 14 instruments on a NASA ER-2 high-altitude aircraft. The primary instrument was a sensitive extended-energy multisphere neutron spectrometer, which was also used to make measurements on the ground. Its detector responses were calculated for neutrons and charged hadrons at energies up to 100 GeV using the radiation transport code MCNPX. We have now recalculated the detector responses including the effects of the airplane structure. We are also using new FLUKA calculations of GCR-induced hadron spectra in the atmosphere to correct for spectrometer counts produced by charged hadrons. Neutron spectra are unfolded from the corrected measured count rates. using the MAXED code. Results for the measured cosmic-ray neutron spectrum (thermal to >10 GeV), total neutron fluence rate, and neutron dose equivalent and effective dose rates, and their dependence on altitude and geomagnetic cutoff generally agree well with results from recent calculations of GCR-induced neutron spectra.
Physical Conditions in the Inner Narrow-Line Region of the Seyfert 2 Galaxy NGC 1068

The physical conditions in the inner narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068 are examined using ultraviolet and optical spectra and photoionization models. The spectra are Hubble Space Telescope archive data obtained with the Faint Object Spectrograph (FOS). We selected spectra of four regions, taken through the 03 FOS aperture covering the full FOS 1200-6800 A wave band. Each region is approximately 20 pc in extent, and all are within 100 pc of the apparent nucleus of NGC 1068. The spectra show similar emission-line ratios from a wide range of ionization states for the most abundant elements. After extensive photoionization modeling, we interpret this result as an indication that each region includes a range of gas densities, which we included in the models as separate components. Supersolar abundances were required for several elements to fit the observed emission-line ratios. Dust was included in the models, but apparently dust-to-gas fraction varies within these regions. The low-ionization lines in these spectra can be best explained as arising in gas that is partially shielded from the ionizing continuum. Although the predicted line ratios from the photoionization models provide a good fit to the observed ratios, it is apparent that the model predictions of electron temperatures in the ionized gas are too low. We interpret this as an indication of additional collisional heating due to shocks and/or energetic particles associated with the radio jet that traverses the NLR of NGC 1068. The density structure within each region may also be the result of compression by the jet.
Lock release lithography for 3D and composite microparticles

We present a method called “Lock Release Lithography (LRL)” that utilizes a combination of channel topography, mask design, and pressure-induced channel deformation to form and release particles in a cycled fashion. This technique provides a means for the high-throughput production of particles with complex 3D morphologies and composite particles with spatially configurable chemistries. In this work, we demonstrate a diverse set of functional particles including those displaying heterogeneous swelling characteristics and containing functional entities such as nucleic acids, proteins and beads.
Iterative estimation of constrained rank-one matrices in noise

We consider the problem of estimating a rank-one matrix in Gaussian noise under a probabilistic model for the left and right factors of the matrix. The probabilistic model can impose constraints on the factors including sparsity and positivity that arise commonly in learning problems. We propose a simple iterative procedure that reduces the problem to a sequence of scalar estimation computations. The method is similar to approximate message passing techniques based on Gaussian approximations of loopy belief propagation that have been used recently in compressed sensing. Leveraging analysis methods by Bayati and Montanari, we show that the asymptotic behavior of the estimates from the proposed iterative procedure is described by a simple scalar equivalent model, where the distribution of the estimates is identical to certain scalar estimates of the variables in Gaussian noise. Moreover, the effective Gaussian noise level is described by a set of state evolution equations. The proposed method thus provides a computationally simple and general method for rank-one estimation problems with a precise analysis in certain high-dimensional settings.
Three-Dimensional Image Reconstruction from Longwave Holograms A Feasibility Study

This paper concerns itself with the investigation of a method for solving the longstanding problem of longitudinal image distortion encountered in longwave (microwave or acoustic) holography that has so far prevented the exploitation of the three-dimensional imaging capability of holography. A scheme for real-time, distortionless image reconstruction from longwave holograms that has the potential of yielding three-dimensional images which can be viewed with the unaided eye is described. The scheme is based on combining the operations of a semiconductor spatial microwave modulator with that of a plasma chamber in which visualization is due to light emission caused by microwave-induced enhanced ionization and luminosity in a weakly ionized r.f. plasma. The scheme has the potential advantage of being implementable in real time when a light value is added. Relatively reasonable level millimeter microwave reconstruction power of .6 watts average is shown to be sufficient for the reconstruction of a three-dimensional image consisting of 1000 resolvable points using commercially available millimeter wave sources, assuming that the local enhanced luminosity is caused by a doubling of the ionization rate in a low frequency r.f. discharge plasma.
Material Balances Under Uncertainty

I. Introduction, 262. — II. The economic environment, 263. — III. Mechanics of planning, 265. — IV. Material reserves, 266. — V. Plan formulation and material balances. 267. — VI. Effects of uncertainty, 268. — VII. Plan execution and the costs of incorrect planning, 270. — VIII. Short- and long-term plans, 272. — IX. Optimal planning and dynamics programming, 273. — X. Sensitivity analysis, 276. — XI. Concluding remarks, 278. — Appendix: Proof of the form of an optimal policy, 278.