cssi/SciSciGPT-SciSciNet huggingface dataset:
The ICF Status and Plans in the United States

The United States continues to maintain its leadership in ICF as it moves toward the goal of ignition. The flagship of the program is the National Ignition Facility (NIF) presently under construction at LLNL. Experiments had begun on the first four beams of the National Ignition Facility just at the time of the last IFSA Conference. Several new successful campaigns have been conducted since then in planar hydrodynamics and hohlraums as well as activating the VISAR diagnostic for equation of state experiments. Highlights of these results will be reviewed. Presently, the four beam experimental capability has been suspended while the first eight beams are being installed as the first step in building out the project. Meanwhile, much progress has been made in developing ignition designs for using NIF. An array of designs having several ablator materials have been shown computationally to ignite with energies ranging from the design energy to as low as 1 MJ of laser energy. Alternative direct drive designs in the NIF indirect drive configuration have been developed by LLE. This wide array of design choices has increased the chance of achieving ignition sooner on the facility. Plans are now being developed to begin an ignition experimental campaign on NIF in 2010, a little over a year after completion of the facility. Other US facilities are also implementing improved capabilities. Petawatt lasers are now under construction at the University of Rochester and Sandia National Laboratory. The Z pulsed power machine at Sandia National Laboratory is being refurbished to improve its performance. The ongoing research program at the OMEGA laser at the University of Rochester and the Z machine at Sandia National Laboratory as well as at the Nike, Trident and Janus lasers remain strong, performing experiments supporting the NIF ignition plan and direct drive ignition. There also is an active program in the broader field of high energy density science on these facilities. These activities will be reviewed here as well as presented in talks throughout the conference.
Existence of a Weak Solution to a Nonlinear Fluid–Structure Interaction Problem Modeling the Flow of an Incompressible, Viscous Fluid in a Cylinder with Deformable Walls

We study a nonlinear, unsteady, moving boundary, fluid–structure interaction (FSI) problem arising in modeling blood flow through elastic and viscoelastic arteries. The fluid flow, which is driven by the time-dependent pressure data, is governed by two-dimensional incompressible Navier–Stokes equations, while the elastodynamics of the cylindrical wall is modeled by the one-dimensional cylindrical Koiter shell model. Two cases are considered: the linearly viscoelastic and the linearly elastic Koiter shell. The fluid and structure are fully coupled (two-way coupling) via the kinematic and dynamic lateral boundary conditions describing continuity of velocity (the no-slip condition), and the balance of contact forces at the fluid–structure interface. We prove the existence of weak solutions to the two FSI problems (the viscoelastic and the elastic case) as long as the cylinder radius is greater than zero. The proof is based on a novel semi-discrete, operator splitting numerical scheme, known as the kinematically coupled scheme, introduced in Guidoboni et al. (J Comput Phys 228(18):6916–6937, 2009) to numerically solve the underlying FSI problems. The backbone of the kinematically coupled scheme is the well-known Marchuk–Yanenko scheme, also known as the Lie splitting scheme. We effectively prove convergence of that numerical scheme to a solution of the corresponding FSI problem.
Evolutionary Algorithm for Artificial Immune System Based Failure Detector Generation and Optimization

The development of an evolutionary algorithm and accompanying software for the generation and optimization of artificial-immune-system-based failure detectors using the negative-selection strategy is presented in this paper. A detector is defined as a subregion of the hyperspace formed by relevant system parameters at abnormal conditions. The utility is a part of an integrated set of methodologies for the detection, identification, and evaluation of a wide variety of aircraft subsystem abnormal conditions. The process of generating and optimizing detectors has several phases. A preliminary phase consists of processing data from flight tests for self definition, including normalization, duplicate removal, and clustering. A first phase of the evolutionary algorithm produces, through an iterative process, a set of detectors that do not overlap with the self and achieve a prescribed level of coverage of the nonself. A second phase consists of a classic genetic algorithm that attempts to optimize the number of detectors, overlapping between detectors, and coverage of the nonself while maintaining no overlap with the self. For this second phase, an initial individual is a set of detectors obtained in the first phase. Specific genetic operators have been defined to accommodate different detector shapes, such as hyperrectangles, hyperspheres, and hyperellipsoids. An interactive design environment has been developed in MATLAB that relies on an advanced user-friendly graphical interface and on a substantial library of alternative algorithms to allow maximum flexibility and effectiveness in the design of detector sets for artificial-immune-system-based abnormal-condition detection. The desirable performance of the proposed methodology is demonstrated by comparing the detection results for aircraft actuator failures of two unoptimized detector sets with the detection results of an optimized detector set. These results show that the algorithm can determine equal or better detection performance while using fewer detectors to cover the nonself.
The effect of anisotropic surface energy on the Rayleigh instability

We determine the linear stability of a rod or wire subject to capillary forces arising from an anisotropic surface energy. The rod is assumed to be smooth with a uniform cross–section given by a two–dimensional equilibrium shape. The stability analysis is based on computing the sign of the second variation of the total energy, which is examined by solving an associated eigenvalue problem. The eigenproblem is a coupled pair of second–order ordinary differential equations with periodic coefficients that depend on the second derivatives of the surface energy with respect to orientation variables. We apply the analysis to examples with uniaxial or cubic anisotropy, which illustrate that anisotropic surface energy plays a significant role in establishing the stability of the rod. Both the magnitude and sign of the anisotropy determine whether the contribution stabilizes or destabilizes the system relative to the case of isotropic surface energy, which reproduces the classical Rayleigh instability.
Symplectic biextensions and a generalization of the Fourier-Mukai transform

A generalization of the Fourier-Mukai transform is proposed. The construction is based on analogy with the classical picture of representations of the Heisenberg group.
Time Evolution in Macroscopic Systems. II. The Entropy

The concept of entropy in nonequilibrium macroscopic systems is investigated in the light of an extended equation of motion for the density matrix obtained in a previous study. It is found that a time-dependent information entropy can be defined unambiguously, but it is the time derivative or entropy production that governs ongoing processes in these systems. The differences in physical interpretation and thermodynamic role of entropy in equilibrium and nonequilibrium systems is emphasized and the observable aspects of entropy production are noted. A basis for nonequilibrium thermodynamics is also outlined.
Synthetic Applications of Nitrenium Ions

Review: [electronic structure and the reactivity of alkyl, aryl, alkylaryl and heteroatm-stabilized nitrenium ions; 225 refs.
Gadolinium-Enhanced Excretory MR Urography After Low-Dose Diuretic Injection: Comparison With Conventional Excretory Urography

PURPOSE: To evaluate the clinical utility and morphologic accuracy of gadolinium-enhanced excretory magnetic resonance (MR) urography after low-dose diuretic injection and to correlate the results with those of conventional urography. MATERIALS AND METHODS: In 71 patients with urologic symptoms, excretory MR urography was performed after intravenous injection of 5-10 mg furosemide and, 30-60 seconds later, 0.1 mmol of gadopentetate dimeglumine per kilogram of body weight. The MR urograms were interpreted by three radiologists, who were blinded to the clinical outcome, and subsequently compared with conventional urograms. RESULTS: Injection of furosemide before contrast material led to rapid, uniform gadolinium distribution inside a sufficiently distended collecting system such that there was no excessive concentration of gadolinium in the urine. In patients with normal or moderately reduced excretory function, this effect allowed complete visualization of the urinary tract within 5-20 minutes of contrast ...
Reynolds-number dependency in homogeneous, stationary two-dimensional turbulence

Turbulent solutions of the two-dimensional Navier-Stokes equations are a paradigm for the chaotic space-time patterns and equilibrium distributions of turbulent geophysical and astrophysical 'thin' flows on large horizontal scales. Here we investigate how homogeneous, stationary two-dimensional turbulence varies with the Reynolds number (Re) in stationary solutions with large-scale, random forcing and viscous diffusion, also including hypoviscous diffusion to limit the inverse energy cascade. This survey is made over the computationally feasible range in Re » 1, approximately between 1.5 × 10 3 and 5.6 × 10 6 . For increasing Re, we witness the emergence of vorticity fine structure within the filaments and vortex cores. The energy spectrum shape approaches the forward-enstrophy inertial-range form k -3 at large Re, and the velocity structure function is independent of Re. All other statistical measures investigated in this study exhibit power-law scaling with Re, including energy, enstrophy, dissipation rates and the vorticity structure function. The scaling exponents depend on the forcing properties through their influences on large-scale coherent structures, whose particular distributions are non-universal. A striking result is the Re independence of the intermittency measures of the flow, in contrast with the known behaviour for three-dimensional homogeneous turbulence of asymptotically increasing intermittency. This is a consequence of the control of the tails of the distribution functions by large-scale coherent vortices. Our analysis allows extrapolation towards the asymptotic limit of Re → ∞, fundamental to geophysical and astrophysical regimes and their large-scale simulation models where turbulent transport and dissipation must be parameterized.
Multifunctional in vivo vascular imaging using near-infrared II fluorescence

In vivo real-time epifluorescence imaging of mouse hind limb vasculatures in the second near-infrared region (NIR-II) is performed using single-walled carbon nanotubes as fluorophores. Both high spatial (∼30 μm) and temporal (<200 ms per frame) resolution for small-vessel imaging are achieved at 1-3 mm deep in the hind limb owing to the beneficial NIR-II optical window that affords deep anatomical penetration and low scattering. This spatial resolution is unattainable by traditional NIR imaging (NIR-I) or microscopic computed tomography, and the temporal resolution far exceeds scanning microscopic imaging techniques. Arterial and venous vessels are unambiguously differentiated using a dynamic contrast-enhanced NIR-II imaging technique on the basis of their distinct hemodynamics. Further, the deep tissue penetration and high spatial and temporal resolution of NIR-II imaging allow for precise quantifications of blood velocity in both normal and ischemic femoral arteries, which are beyond the capabilities of ultrasonography at lower blood velocities.
Improved conservation properties for particle-in-cell simulations with kinetic electrons

It is shown that a simple algorithm which exactly segregates between adiabatic and nonadiabatic electrons in particle-in-cell simulations of drift modes yields excellent conservation properties (e.g. particle number, energy) compared to the conventional δf scheme. The removal of the free streaming term in the evolution of the marker weight is shown to be responsible for the improved linear and nonlinear properties of the simulated plasma.
Synthesis of Barium Hexaferrite by the Oxidation of a Metallic Barium–Iron Precursor

Tapes of the hard magnetic ferrite, BaFe12O19, were synthesized by the oxidation of metallic barium and iron precursors. Milled mixtures of barium flakes and iron powder (Ba:Fe atomic ratio = 1:12) were sealed within fugitive silver tubes and then compacted and formed into tapes by rolling at room temperature. Oxidation and postoxidation heat treatments were conducted over the temperature range 300°–1250°C (the silver was removed after heat treatment at 900°C). Phase-pure BaFe12O19 tapes were produced after heat treatments at peak temperatures of is greater than or equal to $1080°C. Such tapes exhibited room-temperature magnetization values of is greater than or equal to $65.0 emu/g in an applied field of 16.5 kOe (1.32 × 106 A/m). A coercivity of 3.44 kOe (2.75 × 105 A/m) was achieved in a fine-grained (submicrometer) BaFe12O19 tape that had been annealed for 24 h at a peak temperature of 1080°C.
Board Independence and CEO Turnover

This paper analyzes how board independence affects the CEO's ability to extract rents from the firm. The CEO is assumed to possess private information about his ability, which the board needs in order to decide whether to replace him. If the board is more active in removing low quality CEOs, the incumbent is better able to use his information advantage to extract rents. Since the board cannot commit not to renegotiate the contract, a board that is fully independent from the CEO is more active than is efficient ex ante. For this reason, shareholders are better off if the board of directors lacks some independence. The model predicts that a trend toward greater board independence is associated with subsequent trends toward higher CEO turnover, more generous severance packages, and larger stock option grants.
AN INVESTIGATION OF FACTORS ASSOCIATED WITH VARIATIONS IN THE RELATIVE IMPORTANCE OF COMMERCIAL‐BANK RESIDENTIAL REAL‐ESTATE LOANS*

SIGNIFICANT INTERSTATE VARIATIONS in the residential real-estate loan holdings of commercial banks are revealed through an examination of commercial-bank balance sheets. Commercial-bank residential real-estate loans, as a percentage of total bank earning assets (defined as loans plus investments), varied from 2.49 to 24.44 per cent during the 12-year period, June 30, 1953 through June 30, 1965. This dissertation undertakes to investigate factors associated with the observed interstate variations in commercial-bank residential real-estate loans. The sample covers the period June 30, 1953 through June 30, 1965 and includes all banks insured by the Federal Deposit Insurance Corporation. The method used in this study is both analytical and empirical. First, the study identifies factors which might account for the observed variations; i.e., an "explanatory" model is developed based upon previous research and discussion in the areas of residential-housing activity and commercial banking. Second, after suggesting quantitative measurements for the factors included in the explanatory model, the study explores statistically the relationship of these factors to commercial-bank residential real-estate loans. Multiple-correlation analysis is used to estimate the relationship between commercialbank residential real-estate loans, expressed as a percentage of total bank earning assets, and seven explanatory variables. The explanatory variables, which relate to the demand for and supply of residential real-estate credit, include: (1) growth in adult population, (2) current disposable personal income, (3) the cost of mortgage credit, (4) business loans at commercial banks, (5) competition from nonbank, residential real-estate-oriented financial institutions, (6) state banking structures (branch banking versus unit banking) and (7) the liability structure of commercial banks. The statistical procedure consists in computing coefficients of gross determination and coefficients of partial determination for the "explanatory" variables. Regressions are fitted to data for each of the 48 contiguous states and the District of Columbia for each year: a total of 637 observations. The explanatory model accounts for 69.31 per cent of the variation in commercialbank residential real-estate loans. However, four of the explanatory variables-liability structures, state banking structures, current disposable personal income, and the cost of mortgage credit-account for 92 per cent of the explained variation. Thus, the additional "explanatory" variables, as measured for the implicit regression equation, have only nominal explanatory value. The statistical inferences drawn from the significant relationships were: (1) Liability structures of commercial banks. The relationship of commercial-bank liability structure (measured by the ratio of time deposits to total deposits) to residential real-estate loans suggests that commercial bankers may have employed an asset-allocation approach to their investments during the period investigated. Basically,
Global-Local Observer Markov Parameter Identification for System Realization

The observer/Kalman filter identification method uses general input/output data to compute the Markov parameters of an asymptotically stable observer. A state space realization is subsequently obtained from these estimated Markov parameters. However, numerical ill-conditioning, data acquisition, and computer memory constraints may limit the number of measurements that can be processed for Markov parameter estimation. Use of limited measurements then will reduce spatial information. A global-local version of the observer/Kalman filter identification was therefore developed to overcome this dilemma. This method obtains a local state space realization from a reduced set of measurements. A global state space realization is subsequently obtained from a least squares process on the remaining measurements. A six-degree-of-freedom numerical simulation and experimental data from a frame structure are presented to validate the proposed method.
A new system for catalytic enantioselective reduction of achiral ketones to chiral alcohols. Synthesis of chiral α-hydroxy acids

Abstract The reduction of a variety of achiral ketones with catecholborane as stoichiometric reductant and 0.1 equiv of oxazaborolidine 2 as catalyst in toluene at −78°C proceeds in > 95% yield and with enantioselectivities in the range 30:1 to 9: 1, depending on substrate. This reduction procedure is especially advantageous for α,β-enones, thereby providing chiral precursors for a great variety of compounds, for example, α-hydroxy acids.
Determination of the Hubble Constant Using a Two-Parameter Luminosity Correction for Type Ia Supernovae

In this paper, we make a comprehensive determination of the Hubble constant H{sub 0} by using two parameters--the B-V color and the rate of decline {delta}m{sub 15}--to simultaneously standardize the luminosities of all nearby Cepheid-calibrated Type Ia supernovae (SNe Ia) and those of a larger, more distant sample of 29 SNe Ia. Each group is treated in as similar a manner as possible in order to avoid systematic effects. A simultaneous {chi}{sup 2} minimization yields a standardized absolute luminosity of the Cepheid-calibrated supernovae as well as the Hubble constant obtained from the more distant sample. With an adopted LMC distance modulus of 18.50, we find H{sub 0} =62 km s{sup -1} Mpc{sup -1} and a standardized absolute magnitude of -19.46. The sensitivity of H{sub 0} to a metallicity dependence of the Cepheid-determined distances is investigated. The total uncertainty {delta}H{sub 0}, dominated by uncertainties in the primary distance indicators, is estimated to be 5 km s{sup -1} Mpc{sup -1}. (c) (c) 1999. The American Astronomical Society.
Surface tension and viscosity from damped free oscillations of viscous droplets

Damped oscillations of a viscous droplet in vacuum or in an inert gas of negligible density are considered. The dependence of the complex decay factor on the properties of the liquid is investigated for the first time, and numerical results are compared with earlier studies for special cases. A new method is developed to determine both surface tension and viscosity from a single experiment in which the damping rate and frequency of oscillations are measured. The procedure to determine surface tension and viscosity from oscillating levitated liquids is outlined, and results are presented for various modes of shape oscillations.
The sink for outer belt electrons and the electrodynamics of the middle atmosphere

Abstract The middle atmosphere at the foot of the geomagnetic field lines of the outer belt of trapped radiation (about L =4) is a region of dramatically variable electron precipitation. Consequently, electrodynamic phenomena in the atmosphere of this region exhibit significant variation. Typically, the electron population of the outer belt increases by several orders of magnitude during geomagnetic activity associated with the passage of a solar sector boundary; then, over the course of the following week or so, this enormous quantity of trapped electrons precipitates into the atmosphere. However, due to the geometry of the geomagnetic field, this electron precipitation is not distributed evenly: it is concentrated in the sink for outer belt electrons in Antarctica above the Weddell Sea. This “sink” occurs because trapped electrons are scattered to lower equatorial pitch angles by wave–particle interactions. Individual scattering events are smaller than the longitudinal, or hemispheric, variations in the equatorial pitch angle at which electrons are lost into the atmosphere, thus precipitation occurs around 0° longitude in the southern hemisphere for eastward drifting trapped electrons. West of this location, electrons can be temporarily trapped at smaller equatorial pitch angles, but eastward drift transports these particles into the atmosphere, a phenomenon referred to as the drift loss cone. The diurnal modulation of electron precipitation induced by the effect of the dawn-to-dusk geoelectric field is discussed, as well. Experimental data that support this model of electron precipitation are presented. Also, the effect of the outer belt electron sink on the chemistry of the middle atmosphere is introduced.
Could dark energy be vector-like?

In this paper I explore whether a vector field can be the origin of the present stage of cosmic acceleration. In order to avoid violations of isotropy, the vector has be part of a 'cosmic triad', that is, a set of three identical vectors pointing in mutually orthogonal spatial directions. A triad is indeed able to drive a stage of late accelerated expansion in the universe, and there exist tracking attractors that render cosmic evolution insensitive to initial conditions. However, as in most other models, the onset of cosmic acceleration is determined by a parameter that has to be tuned to reproduce current observations. The triad equation of state can be sufficiently close to minus one today, and for tachyonic models it might be even less than that. I briefly analyse linear cosmological perturbation theory in the presence of a triad. It turns out that the existence of non-vanishing spatial vectors invalidates the decomposition theorem, i.e. scalar, vector and tensor perturbations do not decouple from each other. In a simplified case it is possible to analytically study the stability of the triad along the different cosmological attractors. The triad is classically stable during inflation, radiation and matter domination, but it is unstable during (late time) cosmic acceleration. I argue that this instability is not likely to have a significant impact at present.
Facile Synthesis of Functionalized Bis(arylethynyl)benzene Derivatives via Sila–Sonogashira Reaction

Abstract This article describes a facile synthesis of a new series of symmetrical bis(arylethynyl)benzene derivatives via a one-pot coupling reaction between trialkylsilyl protected arylalkynyes and aryldihalides bearing both electron-withdrawing (EW) and electron-donating groups (ED) in the presence of PdCl2(PPh3)2(5%) / CuI/tetrabutylammonium fluoride / triethylamine / tetrahydrofuran (sila–Sonogashira reaction) at room temperature.
Synthesis of Anthranilonitriles by Fragmentation of Isatin Oxime Triflates

Abstract Isatin oxime triflates undergo a facile fragmentation which is promoted by DBU, to form anthranilonitriles after hydrolytic work-up.
The spherical part of the local and global Springer actions

The affine Weyl group acts on the cohomology (with compact support) of affine Springer fibers (local Springer theory) and of parabolic Hitchin fibers (global Springer theory). In this paper, we show that in both situations, the action of the center of the group algebra of the affine Weyl group (the spherical part) factors through the action of the component group of the relevant centralizers. In the situation of affine Springer fibers, this partially verifies a conjecture of Goresky–Kottwitz–MacPherson and Bezrukavnikov–Varshavsky. We first prove this result for the global Springer action, and then deduce from it the result for the local Springer action. This gives an application of global Springer theory to more classical problems.
Does the Mass Accretion Rate Depend on the Radius of the Accreting Star

In some circumstances, the mass accretion rate * onto a compact star may depend not only on external boundary conditions but also on the radius R* of the accreting star. Writing the dependence as * ∝ R, we estimate p for transient binary systems in a quiescent state. We use the observed luminosities L of binary accreting white dwarfs (R* ~ 109 cm) and neutron stars (R* ~ 106 cm) under similar quiescent conditions and estimate * in each system through the relation L ≈ GM**/R*, where M* is the mass of the star. From the limited data available, we infer that p ~ 0.9 ± 0.5 for quiescent binaries. This radial dependence is consistent with radiatively inefficient accretion flows that either are convective or lose mass via a wind.
Gravity-Gradient Stabilization Studies with the Dodge Satellite

ABSTRACT The DODGE satellite was launched on July 1, 1967 into a near-synchronous orbit to demonstrate gravity-gradient stabilization at that high altitude and to experiment with various design parameters and damping techniques. This satellite was the first to be three-axis stabilized at high altitude using gravity-gradient techniques. It continues to function satisfactorily to the present date. Stabilization in pitch and roll to better than ±;10 degrees has been obtained. The yaw stabilization of ±45 degrees has been fairly consistent; with the assistance of a small angular momentum flywheel, yaw accuracy of ±20 degrees was achieved. Magnetic damping of the sample-and-hold type and simulated hysteresis were both successful in damping librations. Efforts with the torsion wire suspended damper boom scheme were not successful, probably due to a mechanical bias in the device. A TV camera system permitted observation of the boom bending under the influence of solar heating. Mechanical hysteresis in the boom bending was observed.
Observations of the Extended Distribution of Ionized Hydrogen in the Plane of M31

We have used the Wisconsin H-Alpha Mapper to observe the spatially extended distribution of ionized hydrogen in M31 beyond the stellar disk. We obtained five sets of observations, centered near the photometric major axis of M31, that extend from the center of the galaxy to just off the edge of the southwestern H I disk. Beyond the bright stellar disk, but within the H I disk, weak Hα is detected with an intensity IHα = 0.05 R. Since M31 is inclined 77° with respect to the line of sight, this implies that the ambient intergalactic ionizing flux on each side of M31 is Φ0 ≤ 1.6 × 104 photons cm-2 s-1. Just beyond the outer boundary of the H I disk, we find no significant detection of Hα and place an upper limit IHα ≤ 0.019 R.
A highly stereoselective synthesis of the octahydronaphthalene subunit of kijanolide and tetronolide

Abstract A highly stereoselective synthesis of the octahydronaphthalene subunit 4 of kijanolide and tetronolide featuring the intramolecular Diels-Alder reaction of tetraenoate 5 is described.
AN ECONOMIC ANALYSIS OF HOUSING CONSTRUCTION EVIDENCE FROM HONG KONG

The often volatile behavior of the Hong Kong housing construction activity is analysed using an annual econometric model for 1975 through 1999. Theory suggests that an increase in house prices leads to a rise in the housing stock, whereas an increase in interest rates leads to a decrease in the housing stock. However, the DiPasquale and Wheaton (1996) model does not seem to work for Hong Kong. Therefore, this study develops and uses an alternative model to show that the long-run equilibrium housing construction is constrained by total space absorption.
Managing difficult patients.

Excerpt Patients who are hostile, too aggressive, too dependent, uncooperative, hysterical, suspicious, and so on can be difficult and frustrating to the physician. All of us erect some defenses ag...
Relative Weighting of Common and Unique Balanced Scorecard Measures by Knowledgeable Decision Makers

Prior research has found that decision makers with limited experience in using the Balanced Scorecard (BSC) ignored measures that reflect the unique strategy of a business unit and based their performance evaluations solely on measures common across units. The purpose of this study is to investigate whether decision makers who have had training and experience in designing BSCs exhibit the same behavior. Results of an experiment show that decision makers who are knowledgeable about the BSC attended to both common and unique measures, but placed greater emphasis on the former. These results hold in both a performance evaluation judgment and in a bonus allocation decision. We attribute these results to the knowledge participants acquired through classroom training on the design of the BSC, but cannot rule out an alternative explanation that our results differ from previous research because participants in our study were undergraduate accounting and information systems majors, rather than M.B.A. students.
Measurements in a Transitional Boundary Layer With Görtler Vortices

The laminar-turbulent transition process has been documented in a concave-wall boundary layer subject to low (0.6 percent) free-stream turbulence intensity. Transition began at a Reynolds number, Rex (based on distance from the leading edge of the test wall), of 3.5 × 105 and was completed by 4.7 × 105 . The transition was strongly influenced by the presence of stationary, streamwise, Gortler vortices. Transition under similar conditions has been documented in previous studies, but because concave-wall transition tends to be rapid, measurements within the transition zone were sparse. In this study, emphasis is on measurements within the zone of intermittent flow. Twenty-five profiles of mean streamwise velocity, fluctuating streamwise velocity, and intermittency have been acquired at five values of Rex , and five spanwise locations relative to a Gortler vortex. The mean velocity profiles acquired near the vortex downwash sites exhibit inflection points and local minima. These minima, located in the outer part of the boundary layer, provide evidence of a “tilting” of the vortices in the spanwise direction. Profiles of fluctuating velocity and intermittency exhibit peaks near the locations of the minima in the mean velocity profiles. These peaks indicate that turbulence is generated in regions of high shear, which are relatively far from the wall. The transition mechanism in this flow is different from that on flat walls, where turbulence is produced in the near-wall region. The peak intermittency values in the profiles increase with Rex , but do not follow the “universal” distribution observed in most flat-wall, transitional boundary layers. The results have applications whenever strong concave curvature may result in the formation of Gortler vortices in otherwise 2-D flows.
Film Boiling Heat Transfer on an Isothermal Vertical Surface

Etudes experimentale et theorique du transfert de chaleur a l'ebullition pelliculaire en convection naturelle de liquides satures sur une surface verticale isotherme
Abscesses in Crohn's disease: outcome of medical versus surgical treatment.

Goals To compare the long-term outcome of medical, percutaneous, and surgical treatment of abdominal and pelvic abscesses complicating Crohn's disease. Study All patients with Crohn's disease and an abdominal abscess treated at one institution during a 10-year period were retrospectively identified. We reviewed hospital and outpatient records and contacted patients for telephone interviews. Outcome measures included abscess recurrence, subsequent surgery for Crohn's disease, and medications used at the time of most recent follow-up. Results Fifty-one subjects were identified, with a mean follow-up of 3.75 years. Fewer patients developed recurrent abscesses after initial surgical drainage and bowel resection (12%) than patients treated with medical therapy only or percutaneous drainage (56%) (p = 0.016). One half of the patients treated nonoperatively ultimately required surgery, whereas only 12% of those treated with initial surgery required reoperation during the follow-up period (p = 0.010). Most failures of nonoperative therapy occurred within 3 months. Medication use was similar between the treatment groups at the time of most recent follow-up. Conclusions In this series, surgical management of abscesses in Crohn's disease was more effective than medical treatment or percutaneous drainage for prevention of abscess recurrence. However, nonoperative therapy prevented subsequent surgery in half of the patients and may be a reasonable treatment option for some patients.
Ab Initio Bond Strengths in Ethylene and Acetylene

Accurate determinations of bond dissociation energies (BDEs) are essential or quantifying the thermodynamics of chemical reactions. The sequential C-H and C-C bond strengths in simple unsaturated hydrocarbons are very poorly known. Up to this point, no high-level ab initio calculations for other BDEs in C{sub 2}H{sub 4} and C{sub 2}H{sub 2} have been performed. Herein the authors report the first systematic study of all of the BDEs in C{sub 2}H{sub 4} and C{sub 2}H{sub 2}, using ab initio generalized valence bond (GVB) and correlation-consistent configuration interaction (CCCI) theory within a DZP basis set, a method developed for calculating accurate (within 1-5 kcal/mol) dissociation energies for single and double bonds.
Magnetotransport near a quantum critical point in a simple metal

We use geometric considerations to study transport properties, such as the conductivity and Hall coefficient, near the onset of a nesting-driven spin-density wave in a simple metal. In particular, motivated by recent experiments on vanadium-doped chromium, we study the variation of transport coefficients with the onset of magnetism within a mean-field treatment of a model that contains nearly nested electron and hole Fermi surfaces. We show that most transport coefficients display a leading dependence that is linear in the energy gap. The coefficient of the linear term, though, can be small. In particular, we find that the Hall conductivity σ x y is essentially unchanged, due to electron-hole compensation, as the system goes through the quantum critical point. This conclusion extends a similar observation we made earlier for the case of completely flat Fermi surfaces to the immediate vicinity of the quantum critical point where nesting is present but not perfect.
Momentum lattice for CHL string

Abstract We propose some analogue of the Narain lattice for CHL string. The symmetries of this lattice are the symmetries of the perturbative spectrum. We explain in this language the known results about the possible gauge groups in compactified theory. For the four-dimensional theory, we explicitly describe the action of S -duality on the background fields. We show that the moduli spaces of the six-, seven- and eight-dimensional compactifications coincide with the moduli spaces of the conjectured type IIA, M-theory and F-theory duals. We classify the rational components of the boundary of the moduli space in seven, eight and nine dimensions.
Enantioselective Total Synthesis of (−)-Citrinadin A and Revision of Its Stereochemical Structure

The first enantioselective total synthesis of (−)-citrinadin A has been accomplished in 20 steps from commercially available materials via an approach that minimizes refunctionalization and protection/deprotection operations. The cornerstone of this synthesis features an asymmetric vinylogous Mannich addition of a dienolate to a chiral pyridinium salt to set the initial chiral center. A sequence of substrate-controlled reactions, including a highly stereoselective epoxidation/ring-opening sequence and an oxidative rearrangement of an indole to furnish a spirooxindole, are then used to establish the remaining stereocenters in the pentacyclic core of (−)-citrinadin A. The successful synthesis of citrinadin A led to a revision of the stereochemical structure of the core substructure of the citrinadins.
Structural Failures in Light-weight Solar Cell Arrays under Thermal Cycling

Several different types of small silicon solar cell arrays mounted on lightweight honeycomb panels and on flexible substrates were subjected to long-term thermal cycling tests between -160 and 600C in dry nitrogen. Other tests included immersion in liquid nitrogen and vibration fatigue tests in excess of one million cycles. The arrays experienced a reduction in output caused by contact failure, fracture in the silicon and cover slide, and disintegration of the honeycomb. Failure modes caused by different cell and interconnect constructions are compared.
Screening for breast cancer with MRI

Breast MRI has emerged as an extremely powerful tool in breast imaging. The use of breast MRI for cancer detection has the potential to change our current algorithms in the detection of breast cancer. By being able to detect cancer that is occult on conventional imaging, such as mammography and sonography, MRI can detect early breast cancer that was previously unseen by conventional imaging. This article reviews the experience of screening breast MRI in the high-risk population. It also reviews the limitations associated with its use. Before breast MRI can be used in the clinical setting, an ability to localize or biopsy MRI detected lesions that are occult on mammography and ultrasound is needed and must be available for these patients. Although the robustness of this technique has generated considerable enthusiasm, our perspective should be tempered by the fact that many questions remain unanswered regarding the use of breast MRI for screening in the nonhigh risk population as well as integration of breast MRI into clinical practice.
Convenient One‐Pot Preparation of Dimethyl Bicyclo[2.2.2]octane‐1,4‐dicarbolylate, a Key Intermediate for a Novel Adenosine A1 Receptor Antagonist

Abstract Dimethyl bicyclo[2.2.2]octane‐1,4‐dicarboxylate (4), a key starting material for a novel adenosine A1 receptor antagonist, was prepared in a one‐pot reaction with convenient workup and improved yield.
Diffuse X-Rays from the Inner 3 Parsecs of the Galaxy

Recent observations with the Chandra X-Ray Observatory have provided us with the capability to discriminate point sources, such as the supermassive black hole Sgr A*, from the diffuse emission within the inner 10'' of the Galaxy. The hot plasma producing the diffuse X-radiation, estimated at ≈7.6 × 1031 ergs s-1 arcsec-2 in the 2-10 keV band, has an rms electron density ≈26 cm-3 and a temperature kT ≈ 1.3 keV, with a total inferred mass of ≈0.1 M☉. At least some of this gas must be injected into the interstellar medium via stellar winds. In the most recent census, about 25 bright, young stars have been identified as the dominant sources of the overall mass efflux from the Galactic center. In this paper we use detailed three-dimensional smoothed particle hydrodynamics (SPH) simulations to study the wind-wind interactions occurring in the inner 3 pc of the Galaxy, with a goal of understanding what fraction, if any, of the diffuse X-ray flux measured by Chandra results from the ensuing shock heating of the ambient medium. We conclude that this process alone can account for the entire X-ray flux observed by Chandra in the inner 10'' of the Galaxy. Understanding the X-ray morphology of the environment surrounding Sgr A* will ultimately provide us with a greater precision in modeling the accretion of gas onto this object, which appears to be relatively underluminous compared to its brethren in the nuclei of other galaxies.
Late light curves of type ia supernovae

We extend earlier efforts to determine whether the late (t$\geq$60d) light-curves of type Ia SNe are better explained by the escape of positrons from the ejecta or by the complete deposition of positron kinetic energy in a trapping magnetic field We find that applying a filter efficiency correction, derived from measured spectra, to B, V, R, and I light-curves after day 50 can produce a consistent bolometric light-curve. The V band is an accurate indicator of total emission in the 3500$\AA$ - 9700$\AA$ range, with a constant fraction ($\sim$25%) appearing in the V band after day 50. This suggests that the V band scales with the bolometric luminosity, and that the deposited energy is instantaneously recycled into optical emission during this epoch. Varying bolometric corrections for the other bands are derived. We see significant evolution of the colors of SNe Ia between day 50 and day 170. We suggest that this may be due to the transition from spectra dominated by emission lines from the radioactive nucleus, $^{56}$Co, to those from the stable daughter nucleus, $^{56}$Fe. We show that the B, V, R, and I band light-curves of SNe Ia after t$\geq$60d can be completely explained with energy deposition from $^{56}$Co decay photons and positrons if substantial positron escape occurs.
THE CHEMICAL AND DYNAMICAL EVOLUTION OF THE GALAXY

Theoretical models of the chemical and dynamical evolution of galaxies are developed and a Galactic structure survey is presented -- both are invaluable tools for uncovering the history of the formation of our Galaxy. Important advances in my theoretical models are non-instantaneous recycling of newly synthesized elements such as iron from Type Ia supernovae (mergers of white dwarf binaries). For the first time, Type Ia supernovae are incorporated in models of stellar remnants as baryonic dark matter. If dark halos consist mainly of white dwarfs, as has been proposed, then an excessive Type Ia supernovae rate is predicted unless the binary fraction of precursor stars is virtually zero. The observed constancy of chemical abundance ratios in halo stars e.g., [O/Fe] ~/= +0.5, signifies enrichment from only Type II supernovae. I explore the timescale for the onset of Type Ia supernovae as an upper limit to the timescale of halo formation. The apparent inconsistency between age differences of 2-3 Gyr in halo stars and the timescale inferred from the onset of Type Ia supernovae (~<0.1 Gyr for a range of models) suggests galaxies formed hierarchically from substructures in which star formation was disrupted before the onset of Type Ia supernovae. Chemical and dynamical evolution models of viscous disks with non-instantaneous recycling are also explored. The patterns of chemical element ratios and scatter in the age-metallicity relationship are calculated. Characterized by radial flow of gas, these models are ideal for exploring new ideas on the formation of galactic bulges from inflow of disk gas. The observed high metallicity of bulge stars may not require an ad hoc variation of the stellar initial mass function, if the bulge is an extension of the disk metallicity gradient. In addition, I present data from an unbiased spectroscopic survey of F-G stars in Selected Areas 51, 57 and 68. Radial velocities accurate to ~<10 km/s are derived. Comparison of the velocity distributions with predictions of Galactic structure models suggests Vrot ~/= 170, sigmaV ~/= 50, sigmaU ~/= 80 km/s for the thick disk. Preliminary distances are derived by photometric parallax, and 3-dimensional velocities calculated using published proper motions. Stellar metallicities can be derived by analysis of spectral line indices composed of weak iron features. Calibration against metallicity standard stars is presented. Evaluation of metallicities of program stars are forthcoming. These data are useful for constraining the existence of a metallicity gradient in the Galactic halo, and determining the correlation of kinematics and chemistry in the disk/halo transition.
Liquid-Phase Bonding of Silicon Nitride Ceramics

Mg-Si-O-N glasses were used to bond dense Si3N4 ceramic pieces by a liquid-phase diffusion bonding mechanism. In this case, it was difficult to achieve defect-free bonding because, at low nitrogen content in the glass, a large mismatch in thermal expansion coefficient produced cracks perpendicular to the bonding glass layer. With an increase in nitrogen content, the glass layer became frothy and contained “bubbles.” However, when a small amount of elemental silicon was added to the glass, volatile reaction was suppressed and intimate bonding was achieved without thermal cracks.
Towards the continuum limit with quenched staggered quarks

We extend previous work on finite-size effects with dynamical staggered quarks to the quenched approximation. We again emphasize the large volume limit that is of interest for spectrum calculations which may hope to approach the experimental values. Relying on new calculations at 6/g2 = 5.7 and recent work with weaker couplings, we extrapolate to the continuum limit and find a nucleon to rho mass ratio in close agreement with the experimental value and the value obtained by extrapolations from calculations with Wilson quarks. Additional calculations that should be done to improve the reliability of the extrapolation are discussed.
A co-volume scheme for the rotating shallow water equations on conforming non-orthogonal grids

A co-volume scheme is introduced for the rotating shallow water equations, in which both velocity components are specified on cell edges, and the thickness variables evolve on both the primary and the dual cell centers. The scheme applies to generic, conforming and non-orthogonal staggered grids, including the widely used lat-lon quadrilateral grids and the Delaunay-Voronoi tessellations. It can be viewed either as coupled C-grid schemes on the primary and dual meshes, or as an generalization of the traditional E-grid scheme on a new non-overlapping grid. Linear dispersive wave analysis shows that, the dispersive relations resolved by either the primary or the dual mesh of a uniform quadrilateral staggered grid is the same as those of the Z-grid scheme. The total wavenumber space resolved by the staggered grid is twice as large, on which the co-volume behaves exactly like the E-grid scheme. On a uniform hexagon-triangular staggered grid, the co-volume has two steady modes and two inertial-gravity modes on the hexagonal mesh, and one steady mode, two inertial gravity modes, and two spurious modes on the triangular mesh. On the wavenumber space resolved by either the hexagonal or the triangular mesh, the inertial-gravity wave modes remain positive and largely monotone. For the nonlinear shallow water equations, the co-volume scheme is shown to preserve the potential vorticity dynamics and the total energy exactly. Numerical results are presented to corroborate and supplement the analyses.