cssi/SciSciGPT-SciSciNet huggingface dataset:
Prospective randomized comparison of human chorionic gonadotropin versus intramuscular progesterone for luteal-phase support in assisted reproduction

The purpose of the study was to determine the impact of two forms of luteal-phase supplementation, human chorionic gonadotropin (hCG) and progesterone (P), during gonadotropin releasing hormone agonist (GnRha)/controlled ovarian hyperstimulation (COH) cycles. The study was a prospective, randomized evaluation of 77 patients. Group 1 patients (n=38) received 2000 IU of hCG, injected subcutaneously, on days 3, 6, 9, and 12 after transvaginal aspiration of the oocytes (TVA=day 0). Group 2 patients (n=39) received 50-mg daily injections of intramuscular (i.m.) P from days 2 to 14 after TVA. Blood tests were performed on days 0, 5, 8, and 12 after TVA. The in vitro fertilization program of a tertiary care institution was the study setting. The main outcome measures were (1) pregnancy and implantation rates; (2) serum estradiol (E), P, and hCG levels; and (3) occurrence of side effects. Clinical pregnancy and implantation rates in group 1 versus group 2 were similar (36.7 vs 35.3 and 12 vs 14%, respectively). Regardless of pregnancy occurrence, on days 8 and 12 after TVA, serum E and P levels were higher in group 1 than group 2 but the resulting E/P ratios were similar. Five of 38 patients (group 1) developed moderate to severe ovarian hyperstimulation syndrome (OHSS) right after the first or second supplementary hCG injection. In these patients, the mean serum E level on the day of hCG trigger injection was about 3250 pg/ml and the number of follicles was between 9 and 17. In 6 of 39 patients (group 2) allergic reactions were observed at the P injection sites. Based on our data, hCG administration as a form of luteal supplementation did not translate, in comparison to P, into significant benefits for the patients. At the same time, it significantly increased the risk of ovarian hyperstimulation. We suggest that whenever, during COH cycles, serum E levels are over 2500 pg/ml and the number of follicles exceeds 10, luteal support with hCG should be excluded.
Extendible characters and monomial groups of odd order

Abstract Let G be a finite p-solvable group, where p is an odd prime. We establish a connection between extendible irreducible characters of subgroups of G that lie under monomial characters of G and nilpotent subgroups of G. We also provide a way to get “good” extendible irreducible characters inside subgroups of G. As an application, we show that every normal subgroup N of a finite monomial odd p , q -group G, that has nilpotent length less than or equal to 3, is monomial.
LiPbSb3S6: A semiconducting sulfosalt with very low thermal conductivity

The new semiconductor LiPbSb3S6 crystallizes in the space group P21/c. The structure is a member of the lillianite homologous series and is composed of layers of PbS archetype Sb/Li–S separated by trigonal-prismatic-coordinated Pb/Li. Electronic band structure calculations indicate an indirect band gap, with direct gaps lying very close in energy. LiPbSb3S6 has one of the lowest thermal conductivities seen in a crystalline material, ∼0.24 W m–1 K–1 at room temperature, and a high resistivity, ∼4 × 109 Ω·cm, and exhibits strong light absorption with a nearly direct band gap of 1.6 eV.
The Cross-Sectional Determinants of Corporate Capital Expenditures: A Multinational Comparison

This study predicts cross-sectional investment (asset-normalized capital expenditures) innovations within the United States, Canada, Great Britain, (mainland) Europe, and Japan. We find that lagged stock returns are the most important cross-sectional predictors of investment increases — except in mainland Europe. American firms tend to react more than Japanese firms but less than Canadian and British firms. However, the differences between Japanese firms and U.S. firms are small. In contrast, European firms appear to conduct their investment policy without much regard for their own lagged stock performance.
Genetic implications for long‐term survivors of childhood cancer

The author reviews current findings regarding inherited cancer predisposition and childhood cancer and proposes development of genetic services for long-term survivors of childhood cancer. Overall, it is suggested that relatively rare germline mutations in the tumor suppressor genes, Rb, p53, and WT1, may have important implications for long-term survivors relevant to familial cancer, second malignant neoplasms, and developmental disorders. Although continued research clearly is needed, planning for genetic services for long-term survivors should begin now.
Networked computing in wireless sensor networks for structural health monitoring

This paper studies the problem of distributed computation over a network of wireless sensors. While this problem applies to many emerging applications, to keep our discussion concrete, we will focus on sensor networks used for structural health monitoring. Within this context, the heaviest computation is to determine the singular value decomposition (SVD) to extract mode shapes (eigenvectors) of a structure. Compared to collecting raw vibration data and performing SVD at a central location, computing SVD within the network can result in significantly lower energy consumption and delay. Using recent results on decomposing SVD, a well-known centralized operation, we seek to determine a near-optimal communication structure that enables the distribution of this computation and the reassembly of the final results, with the objective of minimizing energy consumption subject to a computational delay constraint. We show that this reduces to a generalized clustering problem and establish that it is NP-hard. By relaxing the delay constraint, we derive a lower bound. We then propose an integer linear program (ILP) to solve the constrained problem exactly as well as an approximate algorithm with a proven approximation ratio. We further present a distributed version of the approximate algorithm. We present both simulation and experimentation results to demonstrate the effectiveness of these algorithms .
Pricing for shipping services of online retailers: Analytical and empirical approaches

We develop an analytical model and conduct subsequent empirical analyses using data collected from the online retailers of digital cameras and video games. We find that (1) Internet retailers' base prices are positively associated with on-time delivery probability but shipping charges are negatively associated with on-time delivery probability; (2) Internet retailers will increase base prices when they offer free shipping; and (3) Internet retailers' shipping price difference between the standard and expedited shipping modes increases with the shipping time of standard shipping, but decreases with the shipping time of expedited shipping and also the Internet retailer's on-time probability. Our findings suggest that Internet retailers, to maximize profits, can strategically determine base price and shipping prices, and they can also strategically pace menu pricing for different shipping options.
Making Oxygen with Ruthenium Complexes

Mastering the production of solar fuels by artificial photosynthesis would be a considerable feat, either by water splitting into hydrogen and oxygen or reduction of CO2 to methanol or hydrocarbons: 2H2O + 4hν → O2 + 2H2; 2H2O + CO2 + 8hν → 2O2 + CH4. It is notable that water oxidation to dioxygen is a key half-reaction in both. In principle, these solar fuel reactions can be coupled to light absorption in molecular assemblies, nanostructured arrays, or photoelectrochemical cells (PECs) by a modular approach. The modular approach uses light absorption, electron transfer in excited states, directed long range electron transfer and proton transfer, both driven by free energy gradients, combined with proton coupled electron transfer (PCET) and single electron activation of multielectron catalysis. Until recently, a lack of molecular catalysts, especially for water oxidation, has limited progress in this area. Analysis of water oxidation mechanism for the “blue” Ru dimer cis,cis-[(bpy)2(H2O)RuIIIORuIII(OH2)(b...
Estimates of the Deterrent Effect of Alternative Execution Methods in the United States: 1978–2000

Using a panel of state-level data over the years 1978-2000, this article examines whether the method by which death penalty states conduct their executions affects the per capita incidence of murder in a differential manner. Several measures of the subjective probability of being executed are developed, taking into account the timing of individual executions. The empirical estimates suggest that the deterrent effect of capital punishment is driven primarily by executions conducted by electrocution. None of the other four methods of execution (lethal injection, gas chamber asphyxiation, hanging, and/or firing squad) are found to have a statistically significant impact on the per capita incidence of murder. These results are robust with respect to the manner in which the subjective probabilities of being executed are defined, whether or not a state has a death penalty law on the books, the removal of state and year fixed effects, controls for state-specific time trends, simultaneous control of all execution methods, and controls for other forms of public deterrence. In addition, it is shown that the negative and statistically significant impact of electrocutions is not driven by the occurrence of a "botched" electrocution during the relevant time period.
Meander properties of Venusian channels

Venusian channels, which probably are lava channels, have meander properties that relate to their mode of formation. Their channel meanders probably formed in response to flow dynamics, as in the case of terrestrial rivers, but low sinuosity indicates less developed morphology. The meanders generally follow terrestrial river trends for wavelength ( L ) to width ( W ) ratios, suggesting an equilibrium adjustment of channel form. Slightly higher L/W , in comparison to terrestrial rivers, occurs for Venusian channel types other than sinuous rilles. The unusually low L/W values for some Venusian and lunar sinuous rifles probably indicate modification of original meander patterns by erosional channel widening by lavas. The slightly larger radius of curvature to wavelength ratios of Venusian channels may be attributed to the short time during which the lava channels formed, and/or they may represent a quasi-equilibrium state for the system. Multiple wavelength meanders of specific Venusian channels may have resulted from changes in discharge or from structural control.
Sampling in paley-wiener spaces on combinatorial graphs

A notion of Paley-Wiener spaces on combinatorial graphs is introduced. It is shown that functions from some of these spaces are uniquely determined by their values on some sets of vertices which are called the uniqueness sets. Such uniqueness sets are described in terms of Poincare-Wirtinger-type inequalities. A reconstruction algorithm of Paley-Wiener functions from uniqueness sets which uses the idea of frames in Hilbert spaces is developed. Special consideration is given to the n-dimensional lattice, homogeneous trees, and eigenvalue and eigenfunction problems on finite graphs.
New Modeling of the Lensing Galaxy and Cluster of Q0957+561: Implications for the Global Value of the Hubble Constant

The gravitational lens 0957+561 is modeled utilizing recent observations of the galaxy and the cluster as well as previous VLBI radio data that have been reanalyzed recently. The galaxy is modeled by a power-law elliptical mass density with a small core, while the cluster is modeled by a nonsingular power-law sphere, as indicated by recent observations. Using all of the currently available data, the best-fit model has χ/Ndof ≈ 6, where the χ2 value is dominated by a small portion of the observational constraints used; this value of the reduced χ2 is similar to that of the recent FGSE (Falco, Gorenstein, & Shapiro elliptical) best-fit model of Barkana et al. However, the derived value of the Hubble constant is significantly different from the value derived from the FGSE model. We find that the value of the Hubble constant is given by H0 = 69(1 - κ) and 74(1 - κ) km s-1 Mpc-1 with and without a constraint on the cluster's mass, respectively, where κ is the convergence of the cluster at the position of the galaxy and the range for each value is defined by Δχ2 = χ/Ndof. At present, the best achievable fit for this system is not as good as for PG 1115+080, which has also recently been used to constrain the Hubble constant, and the degeneracy is large. Possibilities for improving the fit and reducing the degeneracy are discussed.
In Situ Active Noise Cancellation Applied to Magnetic Resonance Imaging

Magnetic Resonance Imaging (MRI) is a powerful medical diagnostic tool. Unfortunately, the loud noise produced during scanning is unpleasant and potentially harmful to patients and may limit imaging protocol. A variety of approaches have been proposed to reduce noise exposure. Prior studies have been conducted in a sound quality chamber to aid in the development and implementation of hardware, algorithms, and procedures, which resulted in an active noise cancellation system tailored to conditions present during MRI. The active noise control system generates a secondary sound signal fed into a set of headphones worn by the patient. This system performs well during physical simulation of scanning conditions. In this study, the headphones are worn by a dummy during in-situ MRI scanning. Our specific effort is to take a selected successful experiment under simulated conditions and repeat it during live scanning to evaluate the real time performance of the system conducted in-situ. Evaluation of a common scanning sequence was conducted and the procedure adjusted to maximize the performance of the system. The sound pressure levels (SPLs) at the patient’s ear were measured with and without active control operational, and the results are compared to evaluate the active noise cancellation system’s performance during live scans.Copyright © 2009 by ASME
The Government Deficit and the Exchange Rate

As government deficit spending declines, the question of its impact on the exchange rate is clearly relevant. Recent empirical work has been contradictory. This paper presents a two-country cash-in-advance model to calculate explicitly the long- and short-term effects of government deficit spending on the exchange rate. It is shown that increases in deficit spending result in a short-term appreciation of the currency. The currency will eventually depreciate, to what degree and for how long depending on the method used to finance the deficit.
High-speed logic and memory: past, present and future

By 1950 the logic and memory functions required in data processing were successfully implemented by vacuum-tube technology to demonstrate the feasibility of electronic computers. In the decade of 1950--1960 a large variety of solid-state switching and storage elements and associated circuit schemes were proposed, and pursued to various extent through the research, development and production phases. The present decade, 1960--1970, has witnessed the consolidation of hardware technology to semiconductor logic circuits and magnetic random-access memories to achieve cost and performance advantages in practical systems. The overwhelming success of the semiconductors and the magnetics appears to deter the development of other technologies. Whether or not this trend will continue in the next decade, 1970--1980, depends on the magnitude of the demand and the advancement of science and technology.
Cobalt-Catalyzed Cyclotrimerization of Alkynes in Aqueous Solution

Department of Chemistry, Washington State UniVersityP.O. Box 644630, Pullman, Washington 99164-4630NeXstar Pharmaceuticals, 2860 Wilderness PlaceBoulder, Colorado 80301ReceiVed March 5, 1998Many of the most useful methods for the assembly of cyclicorganic molecules involve transition-metal-catalyzed cycloaddi-tion. Because aromatic rings are central to many biological,pharmaceutical, and polymer molecules, alkyne cyclotrimerizationis an important methodology. Vollhardt was first to realize thepotential of cobalt-catalyzed cyclotrimerization in organic syn-thesis.
Near-degeneracy of several pairing channels in multiorbital models for the Fe pnictides

Weak-coupling approaches to the pairing problem in the iron pnictide superconductors have predicted a wide variety of superconducting ground states. We argue here that this is due both to the inadequacy of certain approximations to the effective low-energy band structure, and to the natural near degeneracy of different pairing channels in superconductors with many distinct Fermi surface sheets. In particular, we review attempts to construct two-orbital effective band models, the argument for their fundamental inconsistency with the symmetry of these materials, and compare the dynamical susceptibilities of two- and five-orbital tight-binding models. We then present results for the magnetic properties, pairing interactions and pairing instabilities within a five-orbital tight-binding random phase approximation model. We discuss the robustness of these results for different dopings, interaction strengths and variations in band structures. Within the parameter space explored, an anisotropic, sign-changing s-wave (A1g) state and a (B1g) state are nearly degenerate, due to the near nesting of Fermi surface sheets.
Finite-time stabilization of nonlinear impulsive dynamical systems☆

Finite-time stability involves dynamical systems whose trajectories converge to a Lyapunov stable equilibrium state in finite time. For continuous-time dynamical systems finite-time convergence implies nonuniqueness of system solutions in reverse time, and hence, such systems possess non-Lipschitzian dynamics. For impulsive dynamical systems, however, it may be possible to reset the system states to an equilibrium state achieving finite-time convergence without requiring non-Lipschitzian system dynamics. In this paper, we develop sufficient conditions for finite-time stability of impulsive dynamical systems using both scalar and vector Lyapunov functions. Furthermore, we design hybrid finite-time stabilizing controllers for impulsive dynamical systems that are robust against full modelling uncertainty. Finally, we present a numerical example for finite-time stabilization of large-scale impulsive dynamical systems.
MacWilliams identity for codes with the rank metric

The MacWilliams identity, which relates the weight distribution of a code to the weight distribution of its dual code, is useful in determining the weight distribution of codes. In this paper, we derive the MacWilliams identity for linear codes with the rank metric, and our identity has a different form than that by Delsarte. Using our MacWilliams identity, we also derive related identities for rank metric codes. These identities parallel the binomial and power moment identities derived for codes with the Hamming metric.
Unbounded fan-in circuits and associative functions

Abstract The computation of finite semigroups using unbounded fan-in circuits are considered. There are constant-depth, polynomial size circuits for semigroup product iff the semigroup does not contain a nontrivial group as a subset. In the case that the semigroup in fact does not contain a group, then for any primitive recursive function f circuits of size O ( nf −1 ( n )) and constant depth exist for the semigroup product of n elements. The depth depends upon the choice of the primitive recursive function f . The circuits not only compute the semigroup product, but every prefix of the semigroup product. A consequence is that the same bounds apply for circuits computing the sum of two n-bit numbers.
Noise trading and stock market volatility

Abstract We investigate the relative effects of fundamental and noise trading on the formation of conditional volatility. We find significant positive (negative) effects of investor sentiments on stock returns (volatilities) for both individual and institutional investors. There are greater positive effects of rational sentiments on stock returns than irrational sentiments. Conversely, there are significant (insignificant) negative effects of irrational (rational) sentiments on volatility. Also, we find asymmetric (symmetric) spillover effects of irrational (rational) bullish and bearish sentiments on the stock market. Evidence in favor of irrational sentiments is consistent with the view that investor error is a significant determinant of stock volatilities.
Time course of perceptual grouping by color

Does perceptual grouping operate early or late in visual processing? One position is that the elements in perceptual layouts are grouped early in vision, by properties of the retinal image, before perceptual constancies have been determined. A second position is that perceptual grouping operates on a postconstancy representation, one that is available only after stereoscopic depth perception, light- ness constancy, and amodal completion have occurred. The present experiments indicate that grouping can operate on both a precon- stancy representation and a postconstancy representation. Perceptual grouping was based on retinal color similarity at short exposure dura- tions and based on surface color similarity at long durations. These results permit an integration of the preconstancy and postconstancy positions with regard to grouping by color.
CHANDRA OBSERVATION OF THE COOLING FLOW CLUSTER ABELL 2052

We present an analysis of the Chandra X-ray observation of A2052, including large-scale properties of the cluster as well as the central region, which includes the bright radio source 3C 317. We present temperature and abundance profiles using both projected and deprojected spectral analyses. The cluster shows the cooling flow signatures of excess surface brightness above a ?-model at the cluster center and a temperature decline into the center of the cluster. For A2052, the temperature drops by a factor of 3 from approximately 3 to 1 keV. The heavy-element abundances initially increase into the center, but decline within 30''. Temperature and abundance maps show that the X-ray-bright shells surrounding the radio source are the coolest and least abundant regions in the cluster. The mass deposition rate in the cooling flow is 26 M? yr-1 < < 42 M? yr-1. This rate is approximately a factor of 3 lower than the rates found with previous X-ray observatories. Based on a stellar population analysis using imaging and spectra at wavelengths spanning the far-ultraviolet to the near-infrared, we find a star formation rate of 0.6 M? yr-1 within a 3'' radius of the nucleus of the central cluster galaxy. Total and gas mass profiles for the cluster are also determined. We investigate additional sources of pressure in the X-ray holes formed by the radio source and limit the temperature of any hot, diffuse, thermal component that provides the bulk of the pressure in the holes to kT 20 keV. We calculate the magnetic field in the bright-shell region and find B ? 11 ?G. The magnetic pressure in the cluster center is significantly lower than the gas pressure. The current luminosity of the central AGN is LX = 7.9 ? 1041 ergs s-1, and its spectrum is well fitted by a power-law model with no excess absorption above the Galactic value. The energy output from several radio outbursts, occurring episodically over the lifetime of the cluster, may be sufficient to offset the cooling flow near the center.
Inversion-Based Feedforward Approach to Broadband Acoustic Noise Reduction

In this article, an inversion-based feedforward control approach to achieve broadband active-noise control is investigated. Broadband active-noise control is needed in many areas, from heating, ventilation and air conditioning (HVAC) ducts to aircraft cabins. Achieving broadband active-noise control, however, is very challenging due to issues such as the complexity of acoustic dynamics (which has no natural roll-off at high frequency, and is often nonminimum phase), the wide frequency spectrum of the acoustic noise, and the critical requirement to overcome the delay of the control input relative to the noise signal. These issues have limited the success of existing feedforward control techniques to the low-frequency range of [0,1] kHz. The modeling issues in capturing the complex acoustic dynamics coupled with its nonminimum-phase characteristic also prevent the use of high-gain feedback methods, making the design of an effective controller to combat broadband noises challenging. In this article, we explore, through experiments, the potential of inversion-based feedforward control approach for noise control over the 1 kHz low-frequency range limit. Then we account for the effect of modeling errors on the feedforward input by a recently developed inversion-based iterative control technique. Experimental results presented show that noise reduction of over 10-15 dB can be achieved in a broad frequency range of 5 kHz by using the inversion-based feedforward control technique.
The conversion of alcohols to halides using a filterable phosphine source

Abstract The conversion of primary and secondary alcohols to chlorides and bromides using 1,2-bis(diphenylphosphino)ethane (diphos) is described. Use of this reagent in lieu of the typical triphenylphosphine–carbontetrahalide complex provides a facile means of purifying the desired halide from the phosphine–oxide byproduct.
The Origin of Radio Emission in Low-Luminosity Active Galactic Nuclei: Jets, Accretion Flows, or Both?

The low-luminosity active galactic nuclei in NGC 3147, NGC 4203, and NGC 4579 have been imaged at four frequencies with the Very Long Baseline Array. The galaxies are unresolved at all frequencies, with size upper limits of 103-104 times the Schwarzschild radii of their central massive black holes. The spectral indices between 1.7 and 5.0 GHz range from 0.2 to 0.4; one and possibly two of the galaxies show spectral turnovers between 5.0 and 8.4 GHz. The high brightness temperatures (Tb 109 K) and relatively straight spectra imply that free-free emission and/or absorption cannot account for the slightly inverted spectra. Although the radio properties of the cores superficially resemble predictions for advection-dominated accretion flows, the radio luminosities are too high compared with the X-ray luminosities. We suggest that the bulk of the radio emission is generated by a compact radio jet, which may coexist with a low radiative efficiency accretion flow.
Sterically demanding, water-soluble alkylphosphines as ligands for high activity Suzuki coupling of aryl bromides in aqueous solvents.

Sterically demanding, water-soluble alkylphosphines have been found to give highly active catalysts for Suzuki coupling of aryl bromides in aqueous solvents. A variety of aryl bromides and boronic acids were coupled in excellent yield. Turnover numbers up to 734 000 mmol/mmol Pd have been achieved under mild conditions.
The blocks of the Brauer algebra in characteristic zero

We determine the blocks of the Brauer algebra in characteristic zero. We also give information on the submodule structure of standard modules for this algebra.
New Approach to Solving Crack Tip Stress Fields for Piezoelectric Materials

A new technique has been developed which solves the anisotropic stress fields in piezoelectric materials. The technique utilizes orthotropic rescaling by rescaling the coordinate axes in terms of certain elastic, piezoelectric, and dielectric material coefficients to obtain the biharmonic equation. The steps which lead to the biharmonic equation require decoupling the stress and electric field components. It is shown that for a certain ratio of dielectric and piezoelectric coefficients, an applied electric field does not change the stress field near a crack tip. The new technique is compared to Stroh’s formalism and finite element modeling.
Well-posedness for the motion of an incompressible liquid with free surface boundary

We study the motion of an incompressible perfect liquid body in vacuum. This can be thought of as a model for the motion of the ocean or a star. The free surface moves with the velocity of the liquid and the pressure vanishes on the free surface. This leads to a free boundary problem for Euler?s equations, where the regularity of the boundary enters to highest order. We prove local existence in Sobolev spaces assuming a ?physical condition?, related to the fact that the pressure of a fluid has to be positive.
Supernova 1987A did not test the neutrino mass hierarchy

Abstract We dispel the misconception that data from SN 1987A favor the normal neutrino mass hierarchy over the inverted hierarchy for sin 2 θ 13 ≳10 −4 . We find comparable fits for the two hierarchies. No bound can be placed on the mixing angle θ 13 even at the 1 σ level.
One- and two-dimensional dyadic Green's functions in chiral media

The one-dimensional and two-dimensional dyadic Green's functions are calculated for 1D and 2D electric sources in an unbounded, lossless, reciprocal chiral medium which is electromagnetically described by a set of symmetric constitutive relations. It is shown that in two- and one-dimensional cases, similar to the three-dimensional case, the medium supports two eigenmodes of propagation with two different wavenumbers. One of them corresponds to the right-circularly polarized wave and the other one to the left-circularly polarized wave. The eigenmode amplitudes a and b are similar to those of the three-dimensional case. >
The physics of flames in Type Ia supernovae

We extend a low Mach number hydrodynamics method developed for terrestrial combustion, to the study of thermonuclear flames in Type Ia supernovae. We discuss the differences between 2-D and 3-D Rayleigh-Taylor unstable flame simulations, and give detailed diagnostics on the turbulence, showing that the kinetic energy power spectrum obeys Bolgiano-Obukhov statistics in 2-D, but Kolmogorov statistics in 3-D. Preliminary results from 3-D reacting bubble calculations are shown, and their implications for ignition are discussed.
Coupling and absorption phenomena in semiconductor-clad dielectric optical waveguides

Unique propagation characteristics arise from the coupling of light between the lossless modes of a dielectric waveguide and the lossy modes supported by an absorptive cladding layer such as a semiconductor. These effects occur because the propagating lightwave couples into a variety of modes that exist in the semiconductor-clad waveguide. Properties such as cladding thickness, refractive index, and absorption level greatly affect modes of the clad waveguide. Such mode effects are due to periodic coupling between the dielectric layer and the semiconductor cladding. The resulting characteristics suggest use in various device applications. Here, we characterize the periodic coupling effect and how it creates unique modes in the clad waveguide structure. We also describe how the refractive index and absorption of the cladding work together to influence the properties of those modes.
Optical pulse-shaping for internal cooling of molecules.

We consider the use of pulse-shaped broadband femtosecond lasers to optically cool rotational and vibrational degrees of freedom of molecules. Since this approach relies on cooling rotational and vibrational quanta by exciting an electronic transition, it is most easily applicable to molecules with similar ground and excited potential energy surfaces, such that the vibrational state is usually unchanged during electronic relaxation. Compared with schemes that cool rotations by exciting vibrations, this approach achieves internal cooling on the orders-of-magnitude faster electronic decay timescale and is potentially applicable to apolar molecules. For AlH+, a candidate species, a rate-equation simulation indicates that rovibrational equilibrium should be achievable in 8 μs. In addition, we report laboratory demonstration of optical pulse shaping with sufficient resolution and power for rotational cooling of AlH+.
Catalytic and Highly Regioselective Cross-Coupling of Aromatic C−H Substrates

This communication describes a new Pd-catalyzed reaction for the highly chemo- and regioselective oxidative cross-coupling of aromatic C−H bonds. This transformation is proposed to proceed via two discrete C−H activation steps whose selectivities are predominantly controlled by proximity to a ligand (first C−H activation) or by the steric environment around the arene C−H bond (second C−H activation). Furthermore, the selectivity of the second C−H activation reaction can be controlled by tuning the ligand environment around the Pd center.
Solving Olin Wilson’s Mystery

ABSTRACT Wilson showed that G8–M1 dwarfs have a range of 0.30 mag in P−V color whereas the color range for earlier stars is 0.12 mag. He attributed the increased range for the later stars to differing hydrogen‐to‐metal ratios in the temperature region where most of the electrons come from the metals. I explored those stars using Hipparcos parallaxes and photometry and with MK types. His effect can be explained without resorting to abundance differences, which are not confirmed elsewhere, by poorer spectral classification from unwidened spectra for the fainter stars and the use of maximum color ranges, rather than dispersions. I also considered, with negative results, the possibility that the Ca ii H and K emission lines or chromospheric activity could cause the large ranges in colors. Different amounts of chromospheric activity do not affect the colors significantly.
Homogeneous, anaerobic (N-heterocyclic carbene)-Pd or -Ni catalyzed oxidation of secondary alcohols at mild temperatures.

The use of aryl chlorides as oxidants for the selective oxidation of a variety of secondary alcohols in anaerobic conditions with (NHC)−Pd and −Ni systems (NHC = N-heterocyclic carbene) at very mild temperatures is presented.
Investigating the effectiveness of the tutorials in introductory physics in multiple instructional settings

This paper examines the educational impact of the implementation of the tutorial activity ``Changes in Energy and Momentum'' from The Tutorials in Introductory Physics in five different instructional settings. These settings include (1) a completely computer-based learning environment and (2) use of cooperative learning groups with varying levels of instructor support. Pre- and post-tests provide evidence that a computer-based implementation falls significantly short of classroom implementations which involve both collaborative learning groups and interactions with a teaching assistance. Other findings provide insight into the importance of certain elements of instructor training and the appropriate use of the tutorial as an initial introduction to a new concept.
High-power-density approaches to magnetic fusion energy: problems and promise of compact Reversed-Field Pinch Reactors (CRFPR)

Abstract If the costing assumptions upon which the positive assessment of conventional large superconducting fusion reactors are based proves overly optimistic, approaches that promise considerably increased system power density and reduced mass utilization will be required. These more compact reactor embodiments generally must operate with reduced shield thickness and resistive magnets. Because of the unique magnetic topology associated with the Reversed-Field Pinch (RFP), the compact reactor embodiment for this approach is particularly attractive from the viewpoint of low-field resistive coils operating with ohmic losses that can be made small relative to the fusion power. The RFP, therefore, is used as one example of a high-power-density (HPD) approach to magnetic fusion energy. A comprehensive system model is described and applied to select a unique, cost-optimized design point that will be used for a subsequent conceptual engineering design of the compact RFP Reactor (CRFPR). This cost-optimized CRFPR design serves as an example of a HPD fusion reactor that would operate with system power densities and mass utilizations that are comparable to fission power plants, these measures of system performance being an order of magnitude more favorable than the conventional approaches to magnetic fusion energy (MFE).
Medical computers from the manufacturer's viewpoint.

The recent surge in the scope of computer applications in medical care has brought with it great strides in patient care, but it has also created a variety of concerns to manufacturers of medical software. The spate of product liability suits, with its potentially crippling effects in terms of product development, makes it increasingly vital that manufacturers engage in prospective planning, to anticipate problems and take steps before legal action ensues, so that all parties--the manufacturer, the hospital, and ultimately, the patient--benefit from the availability of new technology. The Food and Drug Administration (FDA) and Congress are similarly grappling with the implications of this new technology, to assure that patient care is not compromised by products that have not yet been fully tested. The tension between the desire to make technology available to the public and the realities of the present regulatory and litigious climate is the key dilemma facing manufacturers of medical software. Medical software; FDA regulation; Product liability; Legal; Medical devices
Approximation algorithms for combinatorial problems

Simple, polynomial-time, heuristic algorithms for finding approximate solutions to various polynomial complete optimization problems are analyzed with respect to their worst case behavior, measured by the ratio of the worst solution value that can be chosen by the algorithm to the optimal value. For certain problems, such as a simple form of the kanpsack problem and an optimization problem based on satisfiability testing, there are algorithms for which this ratio is bounded by a constant, independent of the problem size. For a number of set covering problems, simple algorithms yield worst case ratios which can grow with the log of the problem size. And for the problem of finding the maximum clique in a graph, no algorithm has been found for which the ratio does not grow at least as fast as n^@e, where n is the problem size and @e>0 depends on the algorithm.
Photocatalytic Reduction and Immobilization of Hexavalent Chromium at Titanium Dioxide in Aqueous Basic Media

The thermodynamic aspects of the photocatalytic reduction of Cr(VI) at TiO[sub 2] are first discussed and contrasted for pH 0 and pH 10 aqueous media. The photocorrosion of TiO[sub 2] is shown to be thermodynamically less favorable in basic media. A scheme for the one-step removal of Cr(VI) at TiO[sub 2] via its reduction and subsequent immobilization [as Cr(OH)[sub 3]] is demonstrated for pH 10 chromate solutions. Dissolved oxygen is shown to inhibit the reduction of Cr(VI). A preliminary kinetics analysis reveals adherence of the initial rate of Cr(VI) reduction to the simple Langmuir model.
Cosmic microwave background radiation of black hole universe

Modifying slightly the big bang theory, the author has recently developed a new cosmological model called black hole universe. This new cosmological model is consistent with the Mach principle, Einsteinian general theory of relativity, and observations of the universe. The origin, structure, evolution, and expansion of the black hole universe have been presented in the recent sequence of American Astronomical Society (AAS) meetings and published recently in a scientific journal: Progress in Physics. This paper explains the observed 2.725 K cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present universe with hundred billion-trillions of solar masses. According to the black hole universe model, the observed cosmic microwave background radiation can be explained as the black body radiation of the black hole universe, which can be considered as an ideal black body. When a hot and dense star-like black hole accretes its ambient materials and merges with other black holes, it expands and cools down. A governing equation that expresses the possible thermal history of the black hole universe is derived from the Planck law of black body radiation and radiation energy conservation. The result obtained by solving the governing equation indicates that the radiation temperature of the present universe can be ∼2.725 K if the universe originated from a hot star-like black hole, and is therefore consistent with the observation of the cosmic microwave background radiation. A smaller or younger black hole universe usually cools down faster. The characteristics of the original star-like or supermassive black hole are not critical to the physical properties of the black hole universe at present, because matter and radiation are mainly from the outside space, i.e., the mother universe.
Fully relativistic B -spline R -matrix calculations for electron collisions with mercury

Results from a fully relativistic 36-state Dirac $B$-spline $R$-matrix (close-coupling) calculation for $e$-Hg collisions are reported. Angle-integrated and angle-differential cross sections for elastic scattering and excitation of the $(6s6p)\phantom{\rule{0.2em}{0ex}}{^{3}P}_{0,1,2}^{o}$ and $(6s6p)\phantom{\rule{0.2em}{0ex}}{^{1}P}_{1}^{o}$ states are compared to experimental data and predictions from other theories. We generally obtain a significant improvement in the agreement between experiment and theory compared to previous distorted-wave and close-coupling attempts, in particular, for the near-threshold region that is dominated by various $6s6{p}^{2}$ negative-ion resonances.
A versatile synthesis of 2-methoxyestradiol, an endogenous metabolite of estradiol which inhibits tubulin polymerization by binding to the colchicine binding site

Abstract A versatile synthesis of 2-methoxyestradiol (7) is described. Formylation of estradiol (1) with hexamethylenetetramine gave 2-formylestradiol (3). Benzylation of the two hydroxyl groups of 3 under basic conditions with benzyl bromide afforded the dibenzyl ether 4. 2-Methoxyestradiol (7) was then obtained from 4 by Baeyer-Villiger oxidation, methylation of the phenol, and debenzylaion.
Optical Measurements And Tests Performed In A Low-Gravity Environment

Shadowgraph and schlieren techniques have been used on board the NASA KC-1 35 low-gravity simulation aircraft to measure gravity-related fluid flow occurring in various experimental configurations. These configurations included cooled and solidified ammonium chloride and water, electrodeposited cobalt in CoSO4 solution, and immiscible and crystal melt solutions. Hardware tests have also been performed for such critical optical system components as lasers and spatial filters to determine their performance and operation under low-gravity conditions. These test results will be used in the design of the various future Shuttle experiments which will utilize advanced optical mea-surement techniques. The design and configuration of the optical systems used to make these measurements and tests are presented, and the performance and operation of these systems and their components under low-gravity conditions are discussed. Some preliminary results are included.
Effects of inductance on the propagation delay and repeater insertion in VLSI circuits

A closed-form expression for the propagation delay of a CMOS gate driving a distributed RLC line is introduced that is within 5% of dynamic circuit simulations for a wide range of RLC loads. It is shown that the error in the propagation delay if inductance is neglected and the interconnect is treated as a distributed RC line can be over 35% for current on-chip interconnect. It is also shown that the traditional quadratic dependence of the propagation delay on the length of the interconnect for RC lines approaches a linear dependence as inductance effects increase. On-chip inductance is therefore expected to have a profound effect on traditional high-performance integrated circuit (IC) design methodologies. The closed-form delay model is applied to the problem of repeater insertion in RLC interconnect. Closed-form solutions are presented for inserting repeaters into RLC lines that are highly accurate with respect to numerical solutions. RC models can create errors of up to 30% in the total propagation delay of a repeater system as compared to the optimal delay if inductance is considered. The error between the RC and RLC models increases as the gate parasitic impedances decrease with technology scaling. Thus, the importance of inductance in high-performance very large scale integration (VLSI) design methodologies will increase as technologies scale.
Properties of baryons containing a heavy quark in the Skyrme model

Abstract The properties of baryons containing one heavy quark are studied in the Skyrme model, where they are treated as bound states of a heavy meson with an SU(2) chiral soliton. In the large-Nc limit, the baryon spectrum is an infinite tower of degenerate states with isospin and spin of the light degrees of freedom I = sl = 0, 1, 2,…, and total spin s = |s l ± 1 2 | . Exotic states with no quark model analogues in the large-Nc limit are found to beunbound. The Σc−Λc mass difference is computed and found to be in good agreement with experiment. The ΣcΣcπ and ΣcΛcπ coupling constants are calculated to leading order in Nc in terms of gA, the axial coupling constant of the nucleon. We discuss the extension of our results to SU(3) chiral solitons.
The Design of Distributed Service Systems

A variety of practical situations involve supplying a particular commodity by some locations to satisfy the demand at others. If the demands and the costs of producing varying amounts of commodity at each location are known, then the question is how much commodity should be supplied by each location in order to minimize the total system cost. Under some relatively general conditions, there will be an optimal solution with the property that the vector of amounts supplied by the various locations is one of a distinguished set of points. In the case of star networks, this combinatorial nature may be exploited to give a very efficient algorithm for finding an optimal solution. A numerical example illustrates the results.
The potential role of the computer in intuition and self development

From 1966--69, several colleagues and I had opportunity to design and implement a prototypical ISVD (Information System for Vocational Decisions). Dr. JoAnn Harris has been good enough to record that the ISVD and several sister computer guidance systems forecast and piloted the following advances in uniting the capabilities of computers and the purposes of guidance:1. "Increased use of visuals to supplement words.2. "Development of programs which will allow counselees to simulate vocational, educational, and personal-social experiences....4. "Development of languages which allow the student to respond to the computer in his own language.5. "Development of programs which will allow the counselee to prepare his own instructions to the computer and thus alter the pre-designed processes."
Total synthesis of +-superstolide A.

A convergent and highly stereocontrolled total synthesis of the cytotoxic macrolide (+)-superstolide A is described. Key features of this synthesis include the use of bimetallic linchpin 36b for uniting the C(1)−C(15) (43) and the C(20)−C(27) (38) fragments of the natural product, a late-stage Suzuki macrocyclization of 49, and a highly diastereoselective transannular Diels−Alder reaction of macrocyclic octaene 4. In contrast, the intramolecular Diels−Alder reaction of pentaenal 5 provided the desired cycloadduct with lower stereoselectivity (6:1:1).