cssi/SciSciGPT-SciSciNet huggingface dataset:
Supergravity resolution of the unification to Planck scale hierarchy

Abstract It is demonstrated how the hierarchy between the gauge coupling unification scale of minimal supersymmetry and the Planck (or string) scale, which resembles in order of magnitude a loop factor, can actually be explained as such in supergravity-coupled supersymmetry. A gauge and global singlet field acquires a linear potential term due to its one-loop supergravity interactions and slides to the desired scale. The singlet field can then provide the seed for the breaking of the unified theory at the appropriate scale via its couplings to fields in the adjoint representation.
Inapproximability for antiferromagnetic spin systems in the tree non-uniqueness region

A remarkable connection has been established for antiferromagnetic 2-spin systems, including the Ising and hard-core models, showing that the computational complexity of approximating the partition function for graphs with maximum degree Δ undergoes a phase transition that coincides with the statistical physics uniqueness/non-uniqueness phase transition on the infinite Δ-regular tree. Despite this clear picture for 2-spin systems, there is little known for multi-spin systems. We present the first analog of the above inapproximability results for multi-spin systems. The main difficulty in previous inapproximability results was analyzing the behavior of the model on random Δ-regular bipartite graphs, which served as the gadget in the reduction. To this end one needs to understand the moments of the partition function. Our key contribution is connecting: (i) induced matrix norms, (ii) maxima of the expectation of the partition function, and (iii) attractive fixed points of the associated tree recursions (belief propagation). The view through matrix norms allows a simple and generic analysis of the second moment for any spin system on random Δ-regular bipartite graphs. This yields concentration results for any spin system in which one can analyze the maxima of the first moment. The connection to fixed points of the tree recursions enables an analysis of the maxima of the first moment for specific models of interest. For k-colorings we prove that for even k, in the tree non-uniqueness region (specifically for semi-translation invariant measures which corresponds to k
Stability and transient motion of a vertical three-lobe bearing system

Stability characteristics and general transient motion of vertical finite width three lobe journal bearing, assuming incompressible fluid with cavitation
Comment: Compulsory Licensing of Patented Pharmaceutical Inventions: Evaluating the Options

In this Comment, the author traces the relevant legislative history pertaining to compulsory licensing of patented pharmaceuticals from the TRIPS Agreement of 1994 to the 2003 waiver to, and later proposed amendment of, article 31, which enables poor countries to obtain needed medicines from other countries that possess manufacturing capacity. The Comment then evaluates recent, controversial uses of the relevant legislative machinery as viewed from different critical perspectives. The Comment shows how developing countries seeking access to essential medicines can collaborate in ways that would avoid undermining incentives to innovation and other social costs attributed to compulsory licensing. It ends by defending the legality of recent measures taken to promote public health in developing countries, and by reminding developed countries that unilateral retaliation against such measures is demonstratably illegal under WTO foundational law and jurisprudence.
Reaction rates for nucleophiles with cyanogen chloride: Comparison with two other digonal carbon compounds

The hydrolysis kinetics of CICN have been reinvestigated from pH 0.0–10.5 and from 18–40°C. In the pH range from 1–5, the hydrolysis rate is invariant and the activation parameters (ΔH‡ = 84 kJ mol−1 and ΔS‡ = −84 J mol−1 K−1) are consistent with water attack. In basic solution the rate is first order each in CICN and OH− concentrations with parameters ΔH‡ and ΔS‡ equal to 82 kJ mol−1 and + 54 J mol−1 K−1, respectively. The rate constants with 20 other donors have been measured. Nitrogen nucleophiles are more reactive than oxygen donors, and an alpha-effect is seen. The constants follow a pattern indicative of attack at carbon. Cyanate in its acid form reacts with nucleophiles. Further points on the cyanate rate–pH profile have been obtained. A chromate-catalyzed hydrolysis can contribute between pH 5–10. Some studies were made of the reaction of cyanate with hydrogen peroxide. Free energy correlations are presented.
One Mill's Response to a Specific Type of Arc Flash Problem

It is sometimes a difficult concept to get across to those most affected, but the greatest arc flash hazards in a mill's electrical distribution system often do not occur at the highest voltages. In fact, they often occur at much lower voltages, such as 480 or 575 V, on the secondary bushings and bus of low-voltage unit substations. This paper describes one mill's response to this challenge.
FOUR DECADES IN THE MEGAGAUSS WORLD

Abstract This paper contains a short history of the generation and application of megagauss magnetic fields obtained by explosive flux compression at Los Alamos over the last four decades, a brief description of the high field systems most commonly used for solid state research, and a survey of results obtained from a Los Alamos shot series in which Russian built high field generators were also used, the forerunner of the later Dirac 1 and 2 shot series.
Tug-of-war with noise: A game-theoretic view of the $p$-Laplacian

Fix a bounded domain Ω⊂Rd, a continuous function F:∂Ω→R, and constants e>0 and 1<p,q<∞ with p−1+q−1=1. For each x∈Ω, let ue(x) be the value for player I of the following two-player, zero-sum game. The initial game position is x. At each stage, a fair coin is tossed, and the player who wins the toss chooses a vector v∈B(0,e) to add to the game position, after which a random noise vector with mean zero and variance (q/p)|v|2 in each orthogonal direction is also added. The game ends when the game position reaches some y∈∂Ω, and player I's payoff is F(y). We show that (for sufficiently regular Ω) as e tends to zero, the functions ue converge uniformly to the unique p-harmonic extension of F. Using a modified game (in which e gets smaller as the game position approaches ∂Ω), we prove similar statements for general bounded domains Ω and resolutive functions F. These games and their variants interpolate between the tug-of-war games studied by Peres, Schramm, Sheffield, and Wilson [15], [16] (p=∞) and the motion-by-curvature games introduced by Spencer [17] and studied by Kohn and Serfaty [9] (p=1). They generalize the relationship between Brownian motion and the ordinary Laplacian and yield new results about p-capacity and p-harmonic measure
Note on the off-shell equivalence between the linear and non-linear sigma models

Abstract As is well known, one can arrange the parameters of the O ( N ) non-linear sigma model to reproduce the low-energy S -matrix elements of the renormalizable O( N ) linear sigma model. In this note we provide details which are necessary in order to obtain the off-shell equivalence between the two theories.
Conformational isomers of 1-fluoro-2-propanol

Abstract The conformational energies of 1-fluoro-2-propanol have been studied using ab initio molecular orbital theory employing minimal (STO-3G) and extended (4-31G) basis sets. The calculations favor the internally H-bonded conformations (I and III). A recent microwave study of the molecule has only detected conformation I, suggesting that conformation III is at least 0.75 kcal/mol higher in energy. Partial geometry optimizations at both levels of theory suggest that the two gauche conformations (I and III) are rather similar energetically and should be experimentally detectable. The conformational energies are analyzed in terms of a Fourier-type expansion of the potential function. The barrier to rotation of the methyl group has also been computed.
Additional therapeutic effects of electroacupuncture in conjunction with conventional rehabilitation for patients with first-ever ischaemic stroke

Objective This study examined the additional therapeutic effects of electroacupuncture for patients with first-ever ischaemic stroke. Design Randomized controlled study. Subjects A total of 63 patients with first-ever ischaemic stroke. Methods The study and control groups underwent a conventional rehabilitation program, with the former receiving an additional 8 courses of electroacupuncture over a period of one month. Therapeutic effects were assessed by the Fugl-Meyer Assessment for motor performance and the Functional Independence Measure (FIM) for the independence of functional performance at t2o and four weeks after treatment, and three months and six months after stroke. Results For total Fugl-Meyer Assessment score, improvement was more significant for the study group relative to the control group at two weeks (16.2 vs 10.6; p = 0.047) and 4 weeks after treatment (27.4 vs 17.1; p = 0.005), and at three months after the stroke (34.7 vs 21.8; p = 0.009). The Fugl-Meyer Assessment scores improved significantly, especially in upper-limb motor function for the study group. There was no statistically significant between-group difference in total FIM score improvement. Conclusion Electroacupuncture can improve motor function, especially in upper-limb motor function, for patients with first-ever ischaemic stroke.
On The β-Decay of 187 Re: An Interface of Atomic And Nuclear Physics And of Cosmochronology

Publisher Summary This chapter discusses how a study of the ratios of various isotopes of Re and Os combined with a knowledge of the half-life T 1/2 of the β decay of 187 Re can be helpful in estimating the age of our galaxy. The chapter defines or expands on astrophysical terminology and concepts and which emphasizes the broad view of the problem rather than the details. The chapter explains the relative production rates of different isotopes of Re and of Os. Studies of the abundances of heavy elements in various stars of known ages suggest that the rate of production of Re has been constant or decreasing, but has not been increasing. The rate of production is linearly proportional to the density of the elements which produced 187 Re atoms.
Abnormal Superfluid Fraction of Harmonically Trapped Few-Fermion Systems

Superfluidity is a fascinating phenomenon that, at the macroscopic scale, leads to dissipationless flow and the emergence of vortices. While these macroscopic manifestations of superfluidity are well described by theories that have their origin in Landau's two-fluid model, our microscopic understanding of superfluidity is far from complete. Using analytical and numerical ab initio approaches, this Letter determines the superfluid fraction and local superfluid density of small harmonically trapped two-component Fermi gases as a function of the interaction strength and temperature. At low temperature, we find that the superfluid fraction is, in certain regions of the parameter space, negative. This counterintuitive finding is traced back to the symmetry of the system's ground state wave function, which gives rise to a diverging quantum moment of inertia ${I}_{q}$. Analogous abnormal behavior of ${I}_{q}$ has been observed in even-odd nuclei at low temperature. Our predictions can be tested in modern cold atom experiments.
How Very Massive Metal-Free Stars Start Cosmological Reionization

The initial conditions and relevant physics for the formation of the earliest galaxies are well specified in the concordance cosmology. Using ab initio cosmological Eulerian adaptive mesh refinement radiation hydrodynamical calculations, we discuss how very massive stars start the process of cosmological reionization. The models include nonequilibrium primordial gas chemistry and cooling processes and accurate radiation transport in the case B approximation using adaptively ray-traced photon packages, retaining the time derivative in the transport equation. Supernova feedback is modeled by thermal explosions triggered at parsec scales. All calculations resolve the local Jeans length by at least 16 grid cells at all times and as such cover a spatial dynamic range of approx.10(exp 6). These first sources of reionization are highly intermittent and anisotropic and first photoionize the small-scale voids surrounding the halos they form in, rather than the dense filaments they are embedded in. As the merging objects form larger, dwarf-sized galaxies, the escape fraction of UV radiation decreases and the H II regions only break out on some sides of the galaxies, making them even more anisotropic. In three cases, SN blast waves induce star formation in overdense regions that were formed earlier from ionization front instabilities. These stars form tens of parsecs away from the center of their parent DM halo. Approximately five ionizing photons are needed per sustained ionization when star formation in 10(exp 6) stellar Mass halos is dominant in the calculation. As the halos become larger than approx.10(exp 7) Stellar Mass, the ionizing photon escape fraction decreases, which in turn increases the number of photons per ionization to 15-50, in calculations with stellar feedback only. Radiative feedback decreases clumping factors by 25% when compared to simulations without star formation and increases the average temperature of ionized gas to values between 3000 and 10,000 K.
Tracking eigenvalues to the frontier of moduli space II: Limits for eigenvalue branches

We prove the existence of limits of real-analytic Laplace eigenvalue branches for real-analytic families of metrics that degenerate along a compact hypersurface.
Numerical Prediction of Wakes in Cascades and Compressor Rotors Including the Effects of Mixing: Part II—Rotor Passage Flow and Wakes Including the Effects of Spanwise Mixing

The results of a numerical investigatian to predict the flow field including wakes and mixing in axial flow compressor rotors has been presented in this paper. The wake behavior in a moderately loaded compressor rotor has been studied numerically using a three-dimensional incompressible Navier-Stokes solver with a high Reynolds number form of the k-∈ turbulence model. The equations are solved using a time- dependent implicit technique. The agreement between the measured data and the predictions is good, including the blade boundary layer profiles, wake mean velocity profiles, and decay
A “core + modules” approach to Fortran standardization

The ANSI FORTRAN standards committee X3J3 has adopted a “core + modules” approach to specifying the next revision of the standard. The motivation for and the projected benefits of this approach are discussed.
Turbulent Statistics from Time-Resolved Piv Measurements of a Jet Using Empirical Mode Decomposition

Empirical mode decomposition is an adaptive signal processing method that when applied to a broadband signal, such as that generated by turbulence, acts as a set of band-pass filters. This process was applied to data from time-resolved, particle image velocimetry measurements of subsonic jets prior to computing the second-order, two-point, space-time correlations from which turbulent phase velocities and length and time scales could be determined. The application of this method to large sets of simultaneous time histories is new. In this initial study, the results are relevant to acoustic analogy source models for jet noise prediction. The high frequency portion of the results could provide the turbulent values for subgrid scale models for noise that is missed in large-eddy simulations. The results are also used to infer that the cross-correlations between different components of the decomposed signals at two points in space, neglected in this initial study, are important.
Speckle Statistics of Localized Waves in Random Media

We discuss remarkably simple statistics of speckle patterns of localized waves. The speckles brightness and structure are associated, respectively, with coupling into and out of the sample, while the speckle statistics reveals the conductance distribution.
Dominating Scale-Free Networks Using Generalized Probabilistic Methods

We study ensemble-based graph-theoretical methods aiming to approximate the size of the minimum dominating set (MDS) in scale-free networks. We analyze both analytical upper bounds of dominating sets and numerical realizations for applications. We propose two novel probabilistic dominating set selection strategies that are applicable to heterogeneous networks. One of them obtains the smallest probabilistic dominating set and also outperforms the deterministic degree-ranked method. We show that a degree-dependent probabilistic selection method becomes optimal in its deterministic limit. In addition, we also find the precise limit where selecting high-degree nodes exclusively becomes inefficient for network domination. We validate our results on several real-world networks, and provide highly accurate analytical estimates for our methods.
The Disk-Magnetosphere Interaction in the Accretion-powered Millisecond Pulsar SAX J1808.4–3658

The recent discovery of the first known accretion-powered millisecond pulsar with the Rossi X-Ray Timing Explorer provides the first direct probe of the interaction of an accretion disk with the magnetic field of a weakly magnetic (B 1010 G) neutron star. We demonstrate that the presence of coherent pulsations from a weakly magnetic neutron star over a wide range of accretion rates places strong constraints on models of the disk-magnetosphere interaction. We argue that the simple 3/7 scaling law for the Keplerian frequency at the magnetic interaction radius, widely used to model disk accretion onto magnetic stars, is not consistent with observations of SAX J1808.4-3658 for most proposed equations of state for stable neutron stars. We show that the usually neglected effects of multipole magnetic moments, radiation drag forces, and general relativity must be considered when modeling such weakly magnetic systems. Using only very general assumptions, we obtain a robust estimate of μ (1-10) × 1026 G cm3 for the dipole magnetic moment of SAX J1808.4-3658, implying a surface dipole field of ~108-109 G at the stellar equator. We therefore infer that after the end of its accretion phase, this source will become a normal millisecond radio pulsar. Finally, we compare the physical properties of this pulsar with those of the nonpulsing, weakly magnetic neutron stars in low-mass X-ray binaries and argue that the absence of coherent pulsations from the latter does not necessarily imply that these neutron stars have significantly different magnetic field strengths from SAX J1808.4-3658.
EFFECTIVE FIELD THEORY FOR NUCLEAR PHYSICS

I summarize the motivation for the effective field theory approach to nuclear physics, and some of its recent accomplishments. 1 Why effective field theory, why nuclear physics? Low energy data is generally insensitive to the details of interactions at short distance. It is therefore difficult to learn about short rangeinteractions; yet by the same token, complete knowledge of the physics at short distances is not required for an accurate understanding of experiments. Effective field theory exploits this fact. The effects of nonlocal interactions at short distance may be represented in terms of local operators in a derivative expansion — the effective Lagrangian. The higher an operator’s dimension, the smaller the effect it has on low energy physics, and hence one can obtain a useful phenomenological theory by retaining operators only up to some dimension, fitting their coefficients to data. Some effective theories arequite useful, such as chiral perturbation theory; some are wildly successful, such as the standard model of particle physics. In this talk I will discuss a new application currently being developed, nuclear effective theory. The utility of effective field theory (EFT) depends on the existence of an energy gap so that “short” and “long” distance physics can be distinguished. It is probably not a useful technique for describing turbulence, or protein folding, for example. In 1990, Weinberg suggested that nuclear physics could be a subject that would benefit from an EFT treatment 1 . In nucleon-nucleon interactions, one can identify the low scales to be m� = 140 MeV, and the nucleon momentum (pF ≃ 280 MeV in nuclear matter), while the high scales
Bootstrap approximation to prediction MSE for state-space models with estimated parameters

We propose a simple but general bootstrap method for estimating the Prediction Mean Square Error (PMSE) of the state vector predictors when the unknown model parameters are estimated from the observed series. As is well known, substituting the model parameters by the sample estimates in the theoretical PMSE expression that assumes known parameter values results in under-estimation of the true PMSE. Methods proposed in the literature to deal with this problem in state-space modelling are inadequate and may not even be operational when fitting complex models, or when some of the parameters are close to their boundary values. The proposed method consists of generating a large number of series from the model fitted to the original observations, re-estimating the model parameters using the same method as used for the observed series and then estimating separately the component of PMSE resulting from filter uncertainty and the component resulting from parameter uncertainty. Application of the method to a model fitted to sample estimates of employment ratios in the U.S.A. that contains eighteen unknown parameters estimated by a three-step procedure yields accurate results. The procedure is applicable to mixed linear models that can be cast into state-space form. (Updated 6th October 2004)
A Unifying Framework for Longitudinal Flying Qualities Criteria

The objective of this paper is to interpret existing flying qualities criteria in a multivariable format based upon state vectors and matrices of stability and control derivatives. State-space methods are shown to be entirely compatible with conventional flying qualities analysis. Furthermore, they lead to a definition of the well-known control anticipation parameter that has potential utility in the evaluation of higher-order aircraft/control systems.
Synthesis of a bipolar phosphatidylethanolamine: A model compound for a membrane-spanning probe

Abstract A general strategy for the synthesis of membrane-spanning bipolar phospholipids equipped with a reactive functional group probe of the membrane environment is described. The strategy is exemplified by the synthesis of a bisphosphatidylethanolamine that is connected through a benzylidene thioacetal of the ω-hydroxy esters at the sn-2 position of the two phosphoglycerol termini.
Relativistic MHD with adaptive mesh refinement

This paper presents a new computer code to solve the general relativistic magnetohydrodynamics (GRMHD) equations using distributed parallel adaptive mesh refinement (AMR). The fluid equations are solved using a finite difference convex ENO method (CENO) in 3 + 1 dimensions, and the AMR is Berger–Oliger. Hyperbolic divergence cleaning is used to control the ∇ ⋅ B = 0 constraint. We present results from three flat space tests, and examine the accretion of a fluid onto a Schwarzschild black hole, reproducing the Michel solution. The AMR simulations substantially improve performance while reproducing the resolution equivalent unigrid simulation results. Finally, we discuss strong scaling results for parallel unigrid and AMR runs.
On Finiteness of Certain Vassiliev Invariants

The best known examples of Vassiliev invariants are the coefficients of a Jones-type polynomial expanded after exponential substitution. We show that for a given knot, the first N Vassiliev invariants in this family determine the rest for some integer N.
Geospatial Resource Description Framework (GRDF) and security constructs

The Semantic Web enables an automated, ontology based information aggregation mechanism. In geographic domain, automatic aggregation is a particularly important task in light of the over-abundance of data formats and types. Because the formats and types are not necessarily uniform or adhere to a particular information structure, aggregating geospatial data with differing formats is a challenging task. The aggregation is extremely useful in many areas such as business, academic, homeland security and public awareness. In this paper, we propose a set of geospatial constructs written in Web Ontology Language (OWL) and collectively referred to as Geographic Resource Description Framework (GRDF).Our goal is to propose a broad, semantics-aware and expressive language for geospatial domain. The most important advantage GRDF has over other geospatial languages is the ability to use logical inference and dynamic content aggregation. We also publish our work on security constructs for GRDF that allows domain experts and software developers to address the security concerns as part of the core development process instead of an ad-hoc course of action.
The Impact of Distance Uncertainties on Local Luminosity and Mass Functions

In order to investigate discrepancies between recent published estimates of the the HI mass function (HIMF), we explore the impact of distance uncertainties on the derivation of the faint end slope of mass and luminosity functions of galaxies in the local volume by deriving HIMFs from mock HI surveys. We consider various survey geometries and depths and compare the HIMFs measured when using ``real'' distances, distances derived by assuming pure Hubble flow and distances assigned from parametric models of the local velocity field. The effect is variable and dependent on the exact survey geometry, but can easily lead to incorrect estimates of the HIMF, particularly at the low mass end. We show that at least part of the discrepancies among recent derivations of the HIMF can be accounted for by the use of different methods to assign distances. We conclude that a better understanding of the local velocity field will be necessary for accurate determinations of the local galaxy luminosity and mass functions.
Modular Forms and Elliptic Curves over the Field of Fifth Roots of Unity

Let F be the cyclotomic field of fifth roots of unity. We computationally investigate modularity of elliptic curves over F.
Synthesis of a C4-epi-C1-C6 fragment of FR901464 using a novel bromolactolization.

A synthesis of a C4-epi-C1−C6 fragment of the antitumor agent FR901464 is reported. The advanced intermediate prepared in this study contains two of the three correct stereocenters found in the C1−C6 moiety of FR901464. For the preparation of this intermediate, we have developed a highly diastereoselective bromolactolization of a δ-alkenyl ketone.
Cultural economy and the creative field of the city

I begin with a rough sketch of the incidence of the cultural economy in US cities today. I then offer a brief review of some theoretical approaches to the question of creativity, with special reference to issues of social and geographic context. The city is a powerful fountainhead of creativity, and an attempt is made to show how this can be understood in terms of a series of localized field effects. The creative field of the city is broken down (relative to the cultural economy) into four major components, namely, (a) intra-urban webs of specialized and complementary producers, (b) the local labor market and the social networks that bind workers together in urban space, (c) the wider urban environment, including various sites of memory, leisure, and social reproduction, and (d) institutions of governance and collective action. I also briefly describe some of the path-dependent dynamics of the creative field. The paper ends with a reference to some issues of geographic scale. Here, I argue that the urban is but one (albeit important) spatial articulation of an overall creative field whose extent is ultimately nothing less than global.
An overlapping-generations model with search

Abstract Search is embedded in an overlapping-generations model. The young participate in a centralized market, and then are matched in pairs in a decentralized market. The old only participate in the centralized market. If the buyer's bargaining power in pairwise trade is close to unity and if the old are risk averse, then the golden-rule rate of money transfer is positive. Such risk aversion, the pairwise meetings, and dependence of the young's saving on the rate of return are necessary for this result.
3-D self-consistent Schrödinger-Poisson solver: the spectral element method

In this paper, we developed an efficient three-dimensional (3-D) nanoelectronic device simulator based on a self-consistent Schrodinger-Poisson solver to simulate quantum transport. An efficient and fast algorithm, the spectral element method (SEM), is developed in this simulator to achieve spectral accuracy where the error decreases exponentially with the increase in the sampling density and the order of the polynomial basis functions, thus significantly reducing the CPU time and memory usage. Perfectly matched layer (PML) boundary method, as an alternative to the open-boundary conditions in NEGF, is applied in this solver to simplify the numerical implementation. The validity of the Schrodinger and Poisson solvers are illustrated by a multiple-terminal device and a spherical charge example, respectively. The utility of the self-consistent Schrodinger-Poisson solver is illustrated by a nanotube example.
Modelling issues for tall reinforced concrete core wall buildings

Reinforced concrete walls are commonly used as the primary lateral force-resisting system for tall buildings. As the tools for conducting nonlinear response history analysis have improved and with the advent of performance-based seismic design, reinforced concrete walls and core walls are often employed as the only lateral force-resisting system. Proper modelling of the load versus deformation behaviour of reinforced concrete walls and link beams is essential to accurately predict important response quantities. Given this critical need, an overview of modelling approaches appropriate to capture the lateral load responses of both slender and stout reinforced concrete walls, as well as link beams, is presented. Modelling of both flexural and shear responses is addressed, as well as the potential impact of coupled flexure–shear behaviour. Model results are compared with experimental results to assess the ability of common modelling approaches to accurately predict both global and local experimental responses. Based on the findings, specific recommendations are made for general modelling issues, limiting material strains for combined bending and axial load, and shear backbone relations. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation of silyl enol ethers from acyloin derivatives using silyllithium reagents

A new method for the regioselective preparation of silyl enol ethers from acyloin derivatives using silyllithium reagents has been developed. Both dimethylphenyl- and methyldiphenylsilyllithium were found to be effective, the latter providing greater stereocontrol. The reaction is believed to proceed via Brook rearrangement assisted by expulsion of the adjacent leaving group. A number of acyclic acyloin derivatives were reacted to form the corresponding silyl enol ethers in good to excellent yield.
α,α-Difluoro-γ-iodo-γ-trimethylsilyl ketones as precursors for the synthesis of α-substituted β-fluoropyrroles☆

Abstract The reaction of α,α-difluoro-γ-iodo-γ-trimethylsilyl ketones with ammonium hydroxide at room temperature followed by treatment with fluoride anion affords α-substituted β-fluoropyrroles in high yields.
A Laser Gyro Evaluation Plan and Test Results

A test program to evaluate laser gyros for Air Force applications is described. The test plan development, facilities and actual test results obtained at the Charles Stark Draper Laboratory, Inc. on a mechancially dithered laser gyro are presented. The test plan addresses methods to evaluate a laser gyro's bias and scale factor under various environments and operational modes. The test techniques are designed for use with: a mini-computer for on-line data analysis and test control, a thermal chamber mounted on an air-bearing table which allows performance evaluation with temperature profile testing, and a data acquisition system for recording available analog voltages for subsequent correlation analyses. Future test plans and additional areas for evaluation are also discussed.© (1978) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
The Angular Two-Point Correlation Function for the FIRST Radio Survey

The FIRST (Faint Images of the Radio Sky at Twenty centimeters) survey now covers 1550 deg2 of sky, where 07h16 α 17h40 and 28°.3 δ 42°. This yields a catalog of 138,665 sources above the survey threshold of 1 mJy, about one-third of which are in double-lobed and multicomponent sources. We have used these data to obtain the first high-significance measurement of the two-point angular correlation for a deep radio sample. We find that the correlation function between 002 and 2° is well fitted by a power law of the form Aθγ, where A ≈ 3 × 10–3 and γ ≈ -1.1. On small scales (θ < 02), double and multicomponent sources are shown to have a larger clustering amplitude than that of the whole sample. Sources with flux densities below 2 mJy are found to have a shallower slope than that obtained for the whole sample, consistent with there being a significant contribution from starbursting galaxies at these faint fluxes. The cross-correlation of radio sources and Abell clusters is determined. A preliminary approach to inferring spatial information is outlined.
Recent advances in the isolation and reactivity of organogold complexes

Homogeneous gold catalysis has been one of the most active research fields in organic chemistry for more than a decade, and it has been also among the most efficient methodologies for forming carbon–carbon or carbon–heteroatom bonds. Recently, a number of organogold intermediates were isolated from stoichiometric reactions, which helps to better understand the mechanisms. Meanwhile, the reactivity of organogold compounds has been attracting the attention of organic chemists in the field. This tutorial review collects the most recent advances in the isolation and reactivity of organogold compounds that may help to open new directions in homogenous gold catalysis.
Evidence for a Young Stellar Population in NGC 5018

Two absorption line indices, Ca II and Hδ/λ4045, measured from high-resolution spectra are used with evolutionary synthesis models to verify the presence of a young stellar population in NGC 5018. The derived age of this population is ~2.8 Gyr with a metallicity roughly solar, and it completely dominates the integrated light of the galaxy near 4000 A.
Gravitational Signature of Jupiter's Deep Zonal Flows

Abstract Calculations predict that, if Jupiter's observed zonal flows persist to a depth ∼1000 km below the cloud layers (corresponding to a pressure ∼10 kbar), they will produce gravity anomalies on the order of a few mgal in high-degree zonal components of the gravitational field, referenced to the field expanded to tenth degree. This signature would be detectable by a low-periapse Jupiter orbiter with a sensitivity to accelerations at the same level as the Galileo orbiter.
Heat-Transfer Measurements in Hypersonic Flow Using Luminescent Coating Techniques

Thedevelopmentandapplicationofhigh-speedimagingandluminescentcoatingtechniquestomeasurefull-e eld surface heat-transfer rates in short-duration hypersonic e ow is presented. Tests were performed on an indented cone model at the 48-in. shock tunnel and the LENS I tunnel facilities at Calspan— University of Buffalo Research Center. Nominal test conditions ranged between Mach numbers of 9.5 and 11.1 and Reynolds numbers of 1:4 £ 10 5 and 3 £ 10 5 m ii 1 with run times of less than 10 ms. Processed submillisecond images show the threedimensional, time-dependent development of the embedded separated e ow and shock/boundary-layer interaction into a steady axisymmetric structure bounded by regions of laminar e ow. Conversion from processed image data to full-e eld heat-transfer measurements were performed using both an in situ calibration with thin-e lm platinum heat-transfer gauges as well as an a priori temperature calibration and transient heat-transfer theory. In situ calibrations displayed excellent correlation with surface-mounted gauges, whereas a priori calibrations showed a larger susceptibility to bias errors.
eDME architecture development and flight-test evaluation

• Enhanced DME capable of meeting the most stringent Navigation and Surveillance accuracy and integrity requirements (RNP 0.3, NACp-8, NIC-7) — Current performance provides a factor of 10 margin compared to requirements • Enhancements transparent to legacy DME/N user • DME transponders require better (stratum-1) frequency reference and beat signal broadcast Other APNT requirements: • Authentication, if desired, with encrypted data broadcast • Provision of time for advanced com by time-synchronizing DME transponder at — slevel
X-Ray and Infrared Observations of Embedded Young Stars in L1630

The HH 24-26 star-forming region in the Lynds 1630 (L1630) dark cloud in Orion contains a remarkable collection of rare Class 0 and Class I protostars, collimated molecular and ionized jets, and a luminous but spatially unresolved ASCA X-ray source. To study the X-ray properties of the embedded protostar population of that region, we have obtained a deep X-ray image with the ACIS-S camera on board the Chandra X-Ray Observatory. A number of Hα emission-line objects were detected in the areas surrounding HH 24-26, of which the weak-line T Tauri star SSV 61 was the brightest source, at a steady luminosity of LX(0.3-10 keV) = 1031.9 ergs s-1. Two Class I protostars aligned with optical jets in HH 24, SSV 63E, and SSV 63W, were also detected, as was the continuum radio source SSV 63NE, which is very likely an extreme Class I or Class 0 object. We observed no X rays from the Class 0 protostars HH 24-MMS and HH 25-MMS, nor any from regions of the cloud bounded by HH 25 and HH 26, at a 2 σ upper limit of LX ~ 1030.0 ergs s-1. HH 26-IR, the Class I object thought to be the origin of the HH 26 flow, was not detected. Near-infrared spectroscopy obtained at the NASA IRTF reveals 3 μm ice bands in the spectra of SSV 59, 63E, 63W, and HH 26-IR, and 2.3 μm CO overtone absorption bands for SSV 61. SSV 60, which lies astride one end of the great arc of nebulosity forming HH 25, exhibits a deep infrared ice band and CO absorption but is not an X-ray source and is most likely a distant background giant of late spectral type.
First-light SOFIA instruments

The Stratospheric Observatory For Infrared Astronomy SOFIA will become operational with the next two years. It will be the biggest astronomical airborne observatory ever build, comprising a 3m-class telescope onboard a Boeing 747SP. A suite of first-light instruments is under development striving for cutting edge technology to make SOFIA a milestone in infrared astronomy. Here we present an overview over the instrumentation and an update on the current status.
Channels of synthesis forty years on: Integrated analysis of spatial economic systems

Isard’s vision of integrated modeling that was laid out in the 1960s book Methods of Regional Science provided a road map for the development of more sophisticated analysis of spatial economic systems. Some forty years later, we look back at this vision and trace developments in a sample of three areas – demographic-econometric integrated modeling, spatial interaction modeling, and environmental-economic modeling. Attention will be focused on methodological advances and their motivation by new developments in theory as well as innovations in the applications of these models to address new policy challenges. Underlying the discussion will be an evaluation of the way in which spatial issues have been addressed, ranging from concerns with regionalization to issues of spillovers and spatial correlation.
On the generalized dining philosophers problem

We consider a generalization of the dining philosophers problem to arbitrary connection topologies. We focus on symmetric, fully distributed systems, and we address the problem of guaranteeing progress and lockout-freedom, even in presence of adversary schedulers, by using randomized algorithms. We show that the well-known algorithms of Lehmann and Rabin do not work in the generalized case, and we propose an alternative algorithm based on the idea of letting the philosophers assign a random priority to their adjacent forks.
Auditor Reputation, Auditor Independence, and the Stock-Market Impact of Andersen's Indictment on Its Client Firms*

In this paper, we study a broad sample of Arthur Andersen clients and investigate whether the decline in Andersen's reputation, due to its criminal indictment on March 14, 2002, adversely affected the stock market's perception of its audit quality. Because these reputa-tional concerns are more of an issue if an auditor's independence is impaired, we investigate the relationship between the abnormal market returns for Andersen clients around the time of the indictment announcement and several fee-based measures of auditor independence. Our results suggest that when news about Andersen's indictment was released, the market reacted negatively to Andersen clients. More importantly, we find that the indictment period abnormal return is significantly more negative when the market perceived the auditor's independence to be threatened. We also examine the abnormal returns when firms announced the dismissal of Andersen as an auditor. Consistent with the audit quality explanation, we document that when firms quickly dismissed Andersen, the announcement returns are significantly higher when firms switched to a Big 4 auditor than when they either switched to non-Big 4 auditors or did not announce the identity of the replacement auditor. Our empirical results support the notion that auditor reputation and independence have a material impact on perceived audit quality and the credibility of audited financial statements, and that the market prices this.
Non-redundant data clustering

Data clustering is a popular approach for automatically finding classes, concepts, or groups of patterns. In practice, this discovery process should avoid redundancies with existing knowledge about class structures or groupings, and reveal novel, previously unknown aspects of the data. In order to deal with this problem, we present an extension of the information bottleneck framework, called coordinated conditional information bottleneck, which takes negative relevance information into account by maximizing a conditional mutual information score subject to constraints. Algorithmically, one can apply an alternating optimization scheme that can be used in conjunction with different types of numeric and non-numeric attributes. We discuss extensions of the technique to the tasks of semi-supervised classification and enumeration of successive non-redundant clusterings. We present experimental results for applications in text mining and computer vision.
Has Latin America's post-reform growth been disappointing?

After years of poor economic performance, many Latin American countries undertook ambitious programs of macroeconomic stabilization and structural reform in recent years. This change in policy created high expectations for the region, and some observers have questioned whether actual growth outcomes have lived up to these expectations. The authors offer evidence that the response of economic growth to reforms in Latin America has not been disappointing. Because of their significant policy changes, and despite a global slowdown, Latin America did well to return to its historic growth rate of 2 percent per capita in 1990-93. Latin America has responded to changes in policy variables, as would have been predicted by the experience of other times and places. Those earlier experiences are summarized by a panel regression spanning many countries and multi-year periods from 1960 to 1993. To get consistent estimates of the parameters linking growth and policy variables, the authors use a dynamic panel methodology that both controls for unobserved time- and country-specific effects and accounts for the likely internal dynamism of the explanatory variables.
Optimal placement of tuning masses for vibration reduction in helicopter rotor blades

Described are methods for reducing vibration in helicopter rotor blades by determining optimum sizes and locations of tuning masses through formal mathematical optimization techniques. An optimization procedure is developed which employs the tuning masses and corresponding locations as design variables which are systematically changed to achieve low values of shear without a large mass penalty. The finite-element structural analysis of the blade and the optimization formulation require development of discretized expressions for two performance parameters: modal shaping parameter and modal shear amplitude. Matrix expressions for both quantities and their sensitivity derivatives are developed. Three optimization strategies are developed and tested. The first is based on minimizing the modal shaping parameter which indirectly reduces the modal shear amplitudes corresponding to each harmonic of airload. The second strategy reduces these amplitudes directly, and the third strategy reduces the shear as a function of time during a revolution of the blade. The first strategy works well for reducing the shear for one mode responding to a single harmonic of the airload, but has been found in some cases to be ineffective for more than one mode. The second and third strategies give similar results and show excellent reduction of the shear with a low mass penalty.
Flowering and inflorescence development of Lachenalia aloides ‘Pearsonii’ as influenced by bulb storage and forcing temperature

Abstract The effect of bulb storage and forcing temperatures on growth, flowering, and inflorescence development and blast of Lachenalia aloides Engl. ‘Pearsonii’ was investigated. Bulb temperature treatments began when about five florets were developed. Bulbs were stored at 10 °C, 12.5 °C, 15 °C, 20 °C, and 25 °C for 15, 30, or 45 days and forced in greenhouses at 17/15 °C and 21/19 °C, day (D)/night (N) temperature. Flowering was accelerated, and leaf length and floret number were reduced, when bulbs were stored at 10 °C, 12.5 °C, or 15 °C for 45 days compared with storing at 20 °C or 25 °C. Flowering was further accelerated by forcing at 17/15 °C compared with 21/19 °C (Experiments 1 and 2). When bulbs were stored at 10 °C, 15 °C, 20 °C, or 25 °C for 4 weeks and grown in greenhouses at 17/15 °C, 21/19 °C, 25/23 °C, and 29/27 °C, D/N temperature, the incidence of inflorescence blast was increased when bulbs were stored at 10° and 15 °C and forced at 25/23 °C compared with low temperatures (Experiment 3). Bulbs were stored at 10 °C, 15 °C, 20 °C, or 25 °C for 4 weeks and forced in greenhouses maintained at 18/16 °C, 22/20 °C, or 26/24 °C, D/N temperature, for 12 weeks. During forcing, plants were subjected to a constant 18/16 °C or temperatures were changed after 4 and 8 weeks (e.g., 18/16 °C–22/20 °C–18/16 °C) (Experiment 4). Inflorescence blast occurred when the temperature was 26/24 °C during the first 4 weeks after potting of bulbs that were stored at 15 °C (83%) and 10 °C (50%). Plants from bulbs stored at higher temperatures did not show inflorescence blast. To produce quality plants with short leaves, many florets, and short floral stems (scape plus inflorescence), it is recommended to store bulbs at 10–15 °C before potting for 30 days and to force at 17/15 °C to accelerate flowering. Inflorescence development during bulb storage at 10 °C and inflorescence blast that occurred after only 3 days of 30 °C was demonstrated using scanning electron microscopy and magnetic resonance imaging techniques.
Legislative history and government documents — Another step in legal research

Abstract This paper discusses the importance of legislative histories and provides techniques for tracing the historical processes of Federal legislation. Additionally, sources for legislative histories are noted.