cssi/SciSciGPT-SciSciNet huggingface dataset:
Infimum Microlensing Amplification of the Maximum Number of Images of n-Point Lens Systems

The total amplification of a source inside a caustic curve of a binary lens is no less than 3. Here we show that the infimum amplification, 3, is satisfied by a family of binary lenses where the source position is at the midpoint of the lens positions, independent of the mass ratio that parameterizes the family. We present a new proof of an underlying constraint that the total amplification of the two positive images is larger than that of the three negative images by 1 inside a caustic. We show that a similar constraint holds for an arbitrary class of n-point lens systems for sources in the "maximal domains." We introduce the notions that a source plane consists of "graded caustic domains" and that the "maximal domain" is the area of the source plane where a source star produces the maximum number of images, n2 + 1. We show that the infimum amplification of a three-point lens is 7 and that the amplification is larger than n2 + 1 - n for n ≥ 4.
NASA breakthrough propulsion physics program

Abstract In 1996, NASA established the Breakthrough Propulsion Physics program to seek the ultimate breakthroughs in space transportation: propulsion that requires no propellant mass, propulsion that attains the maximum transit speeds physically possible, and breakthrough methods of energy production to power such devices. Topics of interest include experiments and theories regarding the coupling of gravity and electromagnetism, vacuum fluctuation energy, warp drives and wormholes, and superluminal quantum effects. Because these propulsion goals are presumably far from fruition, a special emphasis is to identify affordable, near-term, and credible research that could make measurable progress toward these propulsion goals. The methods of the program and the results of the 1997 workshop are presented. This Breakthrough Propulsion Physics program, managed by Lewis Research Center, is one part of a comprehensive, long range Advanced Space Transportation Plan managed by Marshall Space Flight Center.
PLASMA RECOMBINATION AND DIVERTOR DETACHMENT

Abstract We consider the influence on plasma recombination of the formation of negative and molecular ions in a divertor plasma. We take into account different atomic processes (vibrational excitation of molecular hydrogen, electron dissociative attachment, ion conversion, charge exchange and dissociative recombinations, dissociation and ionization, etc.) and find the expression for the effective plasma recombination rate constant from a suitably reduced set of coupled rate equations. We estimate the influence of the recombination process on divertor plasma behavior and find that for AlcatorC-MOD-like parameters plasma recombination due to negative and molecular ions becomes significant in the temperature range below a few eV. We conclude that plasma recombination is a strongly contributing mechanism for the explanation of divertor plasma detachment in low temperature plasmas.
EVALUATION OF STELLATE LESION DETECTION IN A STANDARD MAMMOGRAM DATA SET

We have previously reported on a method for the automatic detection of stellate lesions in digitized mammograms, and on our tests of that method on image data with known diagnoses. This earlier investigation was based on a limited set of 10 test images, each with a stellate lesion. As our approach is one of supervised training, half of the data was used as a training set, and so the performance results were necessarily coarse. Accordingly there is value in testing these algorithms on a larger data set that will not only provide more lesions but also truly undiseased tissue. A new mammogram data set addresses both of these concerns, as it contains examples of twelve stellate lesions, as well as fifty examples of entirely normal mammograms. Further, as this data set has been made widely available to all interested researchers, performance results for specific algorithms on this data set are of particular value, as they can be directly compared to the performance of other algorithms similarly applied. Thus the main contribution of the current paper is to exhaustively evaluate the performance of this stellate lesion detection algorithm on the new mammogram data set. A secondary aim is to present a revision of the spatial integration step which generates the final report of a lesion’s existence, one that facilitates the extraction of ROC performance statistics.
Equivalence and disintegration theorems for Fell bundles and their C*-algebras

We study the C*-algebras of Fell bundles. In particular, we prove the analogue of Renault's disintegration theorem for groupoids. As in the groupoid case, this result is the key step in proving a deep equivalence theorem for the C*-algebras of Fell bundles.
A generalized theorem of the maximum

This paper generalizes the Theorem of the Maximum (Berge [2]) to allow for discontinuous changes in the domain and the objective function. It also provides a geometrical version of the (generalized) theorem.
Seattle syndrome: comments on the reaction to Ashley X

Ashley X is a 9-year-old Seattle girl who has static encephalopathy. She is, and always will be, unable to sit up, roll over, grasp objects, or speak. She is able to experience the cognitive and emotional life of a typical 3–6-month-old child. Ashley’s case history was published in the October 2006 Archives of Pediatrics and Adolescent Medicine (Gunther & Dikema, 2006). The case history indicated that, for the past three years, Ashley has been receiving high doses of oestrogen, a growth attenuation treatment which will result in her remaining relatively small in stature, perhaps 4 feet 6 inches (1.37 m) tall and weighing about 65 or 70 pounds (29–32 kg). Ashley also underwent a hysterectomy, and breast tissue removal to assure the development of small breasts. Ashley's physicians have been subject to a good deal of criticism for performing these procedures, as have her parents for electing them. This brief comment summarizes many of the main objections to what was done to ‘the Ashley treatment’ (as it has become known), and suggests that they are unpersuasive.
Mechanism of the degradation of polyamides

Films of polyamides were exposed to heat, ultra-violet radiant energy, and different atmospheric conditions. The degradation products were collected in some cases and analysed by mass-spectrometric techniques. The unexposed and exposed specimens were examined by the following techniques to obtain information concerning the changes in chemical and physical structure of the polymer: infra-red absorption, ultra-violet absorption, viscosity of solutions, measurement of dielectric constant and dissipation factor, photomicrography, X-ray diffraction, electron microscopy, and effect of organic liquids. In addition, pyrolysis studies were made and some physical properties were determined. The results of the investigation show clearly that no single method gives a complete picture but that the results from several of the methods give an insight into the degradation mechanism. The general course of the degradation of polyamides may be described as follows : (I) splitting of the polymer chain at the C-N linkages; (2) changes in degree of crystallinity or local order; and (3) loss of dipole-associated plasticizers.
Conjecture on the interlacing of zeros in complex Sturm-Liouville problems

The zeros of the eigenfunctions of self-adjoint Sturm–Liouville eigenvalue problems interlace. For these problems interlacing is crucial for completeness. For the complex Sturm–Liouville problem associated with the Schrodinger equation for a non-Hermitian PT-symmetric Hamiltonian, completeness and interlacing of zeros have never been examined. This paper reports a numerical study of the Sturm–Liouville problems for three complex potentials, the large-N limit of a −(ix)N potential, a quasiexactly-solvable −x4 potential, and an ix3 potential. In all cases the complex zeros of the eigenfunctions exhibit a similar pattern of interlacing and it is conjectured that this pattern is universal. Understanding this pattern could provide insight into whether the eigenfunctions of complex Sturm–Liouville problems form a complete set.
Clinical knowledge-based inverse treatment planning

Clinical IMRT treatment plans are currently made using dose-based optimization algorithms, which do not consider the nonlinear dose-volume effects for tumours and normal structures. The choice of structure specific importance factors represents an additional degree of freedom of the system and makes rigorous optimization intractable. The purpose of this work is to circumvent the two problems by developing a biologically more sensible yet clinically practical inverse planning framework. To implement this, the dose-volume status of a structure was characterized by using the effective volume in the voxel domain. A new objective function was constructed with the incorporation of the volumetric information of the system so that the figure of merit of a given IMRT plan depends not only on the dose deviation from the desired distribution but also the dose-volume status of the involved organs. The conventional importance factor of an organ was written into a product of two components: (i) a generic importance that parametrizes the relative importance of the organs in the ideal situation when the goals for all the organs are met; (ii) a dose-dependent factor that quantifies our level of clinical/dosimetric satisfaction for a given plan. The generic importance can be determined a priori, and in most circumstances, does not need adjustment, whereas the second one, which is responsible for the intractable behaviour of the trade-off seen in conventional inverse planning, was determined automatically. An inverse planning module based on the proposed formalism was implemented and applied to a prostate case and a head-neck case. A comparison with the conventional inverse planning technique indicated that, for the same target dose coverage, the critical structure sparing was substantially improved for both cases. The incorporation of clinical knowledge allows us to obtain better IMRT plans and makes it possible to auto-select the importance factors, greatly facilitating the inverse planning process. The new formalism proposed also reveals the relationship between different inverse planning schemes and gives important insight into the problem of therapeutic plan optimization. In particular, we show that the EUD-based optimization is a special case of the general inverse planning formalism described in this paper.
POLYMERS AND PERCOLATION IN TWO DIMENSIONS AND TWISTED N=2 SUPERSYMMETRY

We show how a large class of geometrical critical systems including dilute polymers, polymers at the theta point, percolation and to some extent brownian motion, are described by a twisted N=2 supersymmetric theory with k = 1 (it is broken in the dense polymer phase that is described simply by a η, ξ system). This allows us to give for the first time a consistent conformal field theory description of these problems. The fields that were described so far by formally allowing half integer labels in the Kac table are built and their four point functions studied. Geometrical operators are organized in a few representations of the twisted N = 2 algebra. A noticeable feature is that in addition to Neveu Schwartz and Ramond, a sector with quarter twists has sometimes to be introduced. The algebra of geometrical operators is determined. Fermions boundary conditions are geometrically interpreted, and the partition functions that were so far defined formally as generating functions for the critical exponents are naturally understood, sector by sector. Twisted N = 2 provides moreover a very unified description of all these geometrical models, explaining for instance why the exponents of polymers and percolation coincide. It must be stressed that the physical states in these geometrical problems are not the physical states for string theory, which are usually extracted by the BRS cohomology. In polymers for instance, QBRS is precisely the operator that creates polymers out of the vacuum, such that the topological sector is the sector without any polymers. It seems that twisted N = 2 is the correct continuum limit (in two dimensions) for models with Parisi Sourlas supersymmetry. Some possible explanation of this fact is advanced. As an example of application of N = 2 supersymmetry we discuss in the first appendix the still unsolved problem of backbone of percolation. We conjecture in particular the value D = 25/16 for the fractal dimension of the backbone, in good agreement with numerical computations. Finally some of these ideas are extended to the off critical case in the second appendix where it is shown how to give a meaning to the n → 0 limit of the O(n) model S matrix recently introduced by Zamolodchikov by introducing fermions.
Dynamics and control of a large space antenna

Large space antennae will play an important role in space utilization in the coming decades. In this paper, a control design study of a large space-deployable antenna is presented. For comparative analysis, three controller-estimators were designed and optimized based on requirements of focused communications missions, disturbances, and hardware configurations. One of the major issues investigated is the effect of model error sensitivity. Stability margins, surface accuracy, and pointing errors have been obtained over a wide range of model parameter variations. The results show that structural uncertainties and model errors can cause serious control deterioration. Performance can be improved by strengthening certain structural elements. Flight experiments and in-flight system identification are imperative measures for reducing mission risk and enhancing performance. ARGE space antennae and other large space structures will play an important role in the coming decades as :ommercial applications of space become feasible, especially n the area of communication s. Structures of 10-120 m and arger have been considered by NASA and other government igencies for future missions.1 As the structural size and mass distribution change drastically from those of conventional spacecraft, many difficult control problems arise. The basic Droblem, however, comes in modeling highly flexible structures. Structures of this type are known to have a large lumber of packed modes at very low frequencies. Mode shapes and frequencies cannot be accurately predicted or measured for even a small number of modes at preflight time. This means model uncertainties. Model uncertainties in the :otnrol loop can cause serious consequences, including the Dossibility of making the system unstable. Model order is mother problem having great impact on control design. Using :oday's in-flight computer capability, one can expect to have Dnly a modest-order controller—which often means model ;runcation and which will further performance deterioration. Dynamics and control problems for specific configurations nust be characterized and evaluated in terms of incomplete knowledge of the system dynamics so that the required performance can be insured and the risk reduced. In this paper, the structural dynamics and the control properties for a 64-m-diam mesh deployable antenna are investigated. Some interesting results are presented on the effects of model parameter uncertainties to the system stability, surface accuracy, and pointing accuracy. Critical :ontrol problems are identified and potential solutions recommended. In Sec. II the antenna configuration and the structural dynamic properties are briefly described. The :ontrol design, disturbance assessment, hardware sizing, and instruction of weighting matrices are summarized in Sec. [II. Numerical results are presented in Sec. IV and control design issues relevant to rf (radio frequency) beam pointing in Sec. V. Conclusions are drawn in Sec. VI.
Surface Mesohighs and Mesolows

Abstract Through detailed and remarkably insightful analyses of surface data, Tetsuya Theodore Fujita pioneered modern mesoanalysis, unraveling many of the mysteries of severe storms. In this paper Fujita's contributions to the analysis and description of surface pressure features accompanying tornadic storms and squall lines are reviewed. On the scale of individual thunderstorm cells Fujita identified pressure couplets: a mesolow associated with the tornado cyclone and a mesohigh in the adjacent heavy precipitation area to the north. On larger scales, he found that squall lines contain mesohighs associated with the convective line and wake depressions (now generally called wake lows) to the rear of storms. Fujita documented the structure and life cycles of these phenomena using time–to–space conversion of barograph data. Subsequent investigations have borne out many of Fujita's findings of nearly 50 years ago. His analyses of the surface pressure field accompanying tornadic supercells have been validated...
Regularity lemmas for stable graphs

We develop a framework in which Szemeredi's celebrated Regularity Lemma for graphs interacts with core model-theoretic ideas and techniques. Our work relies on a coincidence of ideas from model theory and graph theory: arbitrarily large half-graphs coincide with model-theoretic instability, so in their absence, structure theorems and technology from stability theory apply. In one direction, we address a problem from the classical Szemeredi theory. It was known that the "irregular pairs" in the statement of Szemeredi's regularity lemma cannot be eliminated, due to the counterexample of half-graphs (i.e., the order property, corresponding to model-theoretic instability). We show that half-graphs are the only essential difficulty, by giving a much stronger version of Szemeredi's regularity lemma for models of stable theories of graphs (i.e. graphs with the non-k�-order property), in which there are no irregular pairs, the bounds are significantly improved, and each component satisfies an indivisibility condition. In the other direction, we take a more model-theoretic approach, and give several new Szemeredi-type partition theorems for models of stable theories of graphs. The first theorem gives a partition of any such graph into indiscernible components, meaning here that each component is either a complete or an empty graph, whose interaction is strongly uniform. This relies on a finitary version of the classic model-theoretic fact that stable theories admit large sets of indiscernibles, by showing that in models of stable theories of graphs one can extract much larger indiscernible sets than expected by Ramsey's theorem. The second and third theorems allow for a much smaller number of components at the cost of weakening the "indivisibility" condition on the components. We also discuss some extensions to graphs without the independence property. All graphs are finite and all partitions are equitable, i.e. the sizes of the components differ by at most 1. In the last three theorems, the number of components depends on the size of the graph; in the first theorem quoted, this number is a function ofonly as in the usual Szemeredi regularity lemma.
A family of Sobolev orthogonal polynomials on the unit ball

A family of orthonormal polynomials on the unit ball B^d of R^d with respect to the inner product[email protected]!"B"^"[email protected][([email protected][email protected]?^2)f(x)]@D[([email protected][email protected]?^2)g(x)]dx,where @D is the Laplace operator, is constructed explicitly.
Simulating the Cooling Flow of Cool-core Clusters

We carry out high-resolution adaptive mesh refinement simulations of a cool core cluster, resolving the flow from Mpc scales down to pc scales. We do not (yet) include any active galactic nucleus (AGN) heating, focusing instead on cooling in order to understand how gas reaches the supermassive black hole at the center of the cluster. We find that, as the gas cools, the cluster develops a very flat temperature profile, undergoing a cooling catastrophe only in the central 10-100 pc of the cluster. Outside of this region, the flow is smooth, with no local cooling instabilities, and naturally produces very little low-temperature gas (below a few keV), in agreement with observations. The gas cooling in the center of the cluster rapidly forms a thin accretion disk. The amount of cold gas produced at the very center grows rapidly until a reasonable estimate of the resulting AGN heating rate (assuming even a moderate accretion efficiency) would overwhelm cooling. We argue that this naturally produces a thermostat which links the cooling of gas out to 100 kpc with the cold gas accretion in the central 100 pc, potentially closing the loop between cooling and heating. Isotropic heat conduction does not affect themore » result significantly, but we show that including the potential well of the brightest cluster galaxy is necessary to obtain the correct result. Also, we found that the outcome is sensitive to resolution, requiring very high mass resolution to correctly reproduce the small transition radius.« less
Prospects for Antineutrino Running at MiniBooNE

We outline a program of antineutrino cross-section measurements necessary for the next generation of neutrino oscillation experiments, that can be performed with one year of data at MiniBooNE. We describe three independent methods of constraining wrong-sign (neutrino) backgrounds in an antineutrino beam, and their application to the MiniBooNE antineutrino cross section measurements.
Semi-empirical Study of a pH-switchable [2] rotaxane

Abstract Semi-empirical (AM1) electronic structure calculations are reported on a pH-switchable [2] rotaxane whose synthesis was reported in [Angew. Chem. Int. Ed. 36 (1997) 1904]. The [2] rotaxane possesses two cationic binding sites, with different affinities toward dibenzo [24] crown-8 (the ring component of the [2] rotaxane) depending upon the pH of the system. The computational results capture this pH-sensitive bistability, the key device-like characteristic of the rotaxane.
Calibration technique for SAR analog-to-digital converters

A self-calibration technique was developed for SAR analog-to-digital converters that employ binary-weighted capacitors. High-accuracy calibration is achieved by finding and correcting the mismatch of each capacitor independently. The mismatch errors are extracted at power-up, and corrected by individual calibration DACs during the conversion. Unlike in previous schemes, in the proposed method the residual error in the calibration of a capacitor does not affect the calibration of any other capacitor. Simulation results show that the proposed method is also insensitive to the non-idealities of the calibration DACs.
The Kinematics of Thick Disks in Nine External Galaxies

We present kinematic measurements of the thick and thin disks in two edge-on galaxies. We have derived stellar rotation curves at and above the galaxies' midplanes using Ca II triplet features measured with the GMOS spectrograph on Gemini North. In one galaxy, FGC 1415, the kinematics above the plane shows clear rotation that lags that of the midplane by ~20%-50%, similar to the behavior seen in the Milky Way. However, the kinematics of the second galaxy, FGC 227, is quite different. The rotation above the plane is extremely slow, showing 25% of the rotation speed of the stars at the midplane. We decompose the observed rotation curves into a superposition of thick- and thin-disk kinematics, using two-dimensional fits to the galaxy images to determine the fraction of thick-disk stars at each position. We find that the thick disk of FGC 1415 rotates at 30%-40% of the rotation speed of the thin disk. In contrast, the thick disk of FGC 227 is very likely counterrotating if it is rotating at all. These observations are consistent with the velocity dispersion profiles that we measure for each galaxy. The detection of counterrotating thick disks conclusively rules out models in which the thick disk forms either during monolithic collapse or from vertical heating of an earlier thin disk. Instead, the data strongly support models in which the thick disk forms from direct accretion of stars from infalling satellites.
Auroral kilometric radiation - A theoretical review

A number of theories have been proposed in recent years to explain auroral kilometric radiation. These include an anisotropic velocity distribution instability, mode conversion of electron cyclotron waves to ordinary mode radiation, soliton radiation, beam-driven instability of electromagnetic waves via low-frequency turbulence, a loss cone instability, beating of coherent electrostatic waves, and beam amplification of electromagnetic waves via coherent density fluctuations. These will all be reviewed, and comparisons of prediction made with observations. Emphasis will be placed on the three recent proposals.
Rh-catalyzed alkene oxidation: a highly efficient and selective process for preparing N-alkoxysulfonyl aziridines

Abstract Unique alkoxysulfonyl aziridine heterocycles were prepared through selective intra- and intermolecular alkene oxidation reactions. These methods are general and perform efficiently at low Rh-catalyst loadings (1–2 mol %) with only a slight excess of an inexpensive commercial oxidant, PhI(OAc)2. For intermolecular processes, trichloroethylsulfamate was identified as a novel and markedly effective N-atom source, allowing reactions to be conducted with limiting amounts of the olefin substrate. The aziridine products submit to facile, nucleophilic ring opening; these processes are regioselective and can be used to prepare polyfunctionalized amines, including α-aminoketones via the direct addition of Me2SO.
Spin-dependent macroscopic forces from new particle exchange

Long-range forces between macroscopic objects are mediated by light particles that interact with the electrons or nucleons, and include spin-dependent static components as well as spin- and velocity-dependent components. We parametrize the long-range potential between two fermions assuming rotational invariance, and find 16 different components. Applying this result to electrically neutral objects, we show that the macroscopic potential depends on 72 measurable parameters. We then derive the potential induced by the exchange of a new gauge boson or spinless particle, and compare the limits set by measurements of macroscopic forces to the astrophysical limits on the couplings of these particles.
Simulation of Plasma Fluxes to Material Surfaces with Self-consistent Edge Turbulence and Transport for Tokamaks

The edge-plasma profiles and fluxes to the divertor and walls of a tokamak with a magnetic X-point are simulated by coupling a 2D transport code (UEDGE) and a 3D turbulence code (BOUT). A relaxed iterative coupling scheme is used where each code is run on its characteristic time scale, resulting in a statistical steady state. Plasma variables of density, parallel velocity, and separate ion and electron temperatures are included, together with a fluid neutral model for recycling neutrals at material surfaces. Results for the DIII-D tokamak parameters show that the turbulence is preferentially excited in the outer radial region of the edge where magnetic curvature is destabilizing, yielding substantial plasma particle flux to the main chamber walls. The coupled transport/turbulence simulation technique provides a strategy to achieve physics-based predictions for future device performance.
R2 around the world: New theory and new tests

Abstract Morck, Yeung and Yu show that R2 is higher in countries with less developed financial systems and poorer corporate governance. We show how control rights and information affect the division of risk bearing between managers and investors. Lack of transparency increases R2 by shifting firm-specific risk to managers. Opaque stocks with high R2s are also more likely to crash, that is, to deliver large negative returns. Using stock returns from 40 stock markets from 1990 to 2001, we find strong positive relations between R2 and several measures of opaqueness. These measures also explain the frequency of crashes.
Geometric proofs of horn and saturation conjectures

We provide a geometric proof of the Schubert calculus interpretation of the Horn conjecture, and show how the saturation conjecture follows from it. The geometric proof gives a strengthening of Horn and saturation conjectures. We also establish transversality theorems for Schubert calculus in non-zero characteristic. Some parts of the version posted in Nov 2002 (concerning explicit invariants constructed from Schubert calculus) have been removed from this version. They have appeared separately in IMRN 2004, no. 69, pages 3709--3721 " Invariant theory of GL(n) and Intersection theory of Grassmannians"
Non-Gaussian Statistical Timing Analysis Using Second-Order Polynomial Fitting

For nanometer manufacturing, process variation causes significant uncertainty for circuit performance verification. Statistical static timing analysis (SSTA) is thus developed to estimate timing distribution under process variation. Most existing SSTA techniques have difficulty in handling the non-Gaussian variation distribution and nonlinear dependence of delay on variation sources. To address this problem, we first propose a new method to approximate the max operation of two non-Gaussian random variables through second-order polynomial fitting. With such approximation, we then present new non-Gaussian SSTA algorithms for three delay models: quadratic model, quadratic model without crossing terms (semiquadratic model), and linear model. All the atomic operations (max and sum) of our algorithms are performed by closed-form formulas; hence, they scale well for large designs. Experimental results show that compared to the Monte Carlo simulation, our approach predicts the mean, standard deviation, skewness, and 95% percentile point within 1%, 1%, 6%, and 1% error, respectively.
Finite element procedures for large strain elastic-plastic theories

Abstract In a unified approach, the virtual work equations in rate form and in incremental forms are derived rigorously for elastic-plastic continuum subjected to large strains. The finite element procedures for the analyses of elastic-plastic solid based on Lee's theory and the Green-Naghdi theory are presented. Also, it is shown that transformations can be performed among the Eulerian, the Total-Lagrangian, and the Updated-Lagrangian formulations, and among different forms of constitutive relations, without any approximation.
An empirical Bayesian approach to stein-optimal covariance matrix estimation

This paper proposes a conjugate Bayesian regression model to estimate the covariance matrix of a large number of securities. Characterizing the return generating process with an unrestricted factor model, prior beliefs impose structure while preserving estimator consistency. This framework accommodates economically-motivated prior beliefs and nests shrinkage covariance matrix estimators, providing a common model for their interpretation. Minimizing posterior finite-sample square error delivers a fully-automated covariance matrix estimator with beliefs that become diffuse as the sample grows relative to the dimension of the problem. In application, this Stein-optimal posterior covariance matrix performs well in a large set of simulation experiments.
Scaling Law for the Cosmological Constant from Quantum Cosmology with Seven Extra Dimensions

According to a model of quantum cosmology the maximum number of degrees of freedom allowed in our three dimensions was determined by the size of seven extra dimensions in an initial excited state before inflation. The size of the extra dimensions can be inferred from a simple scheme for unifying the strong force and gravity. Coupled with the Bekenstein-Hawking entropy bound, these considerations lead to a scaling law for the cosmological constant that has been proposed independently by several authors.
Alkoxy and cyclic ether oxygens exhibit disparate capabilities for directing ortho lithiation

Abstract Metalation of 4a and 4b with n-butyllithium under kinetically controlled conditions (C6H6, 20 °C or Et2O, TMEDA (2 equiv), 20 °C) leads to preferred deprotonation α to the heterocyclic ring.
Langlands duality for Hitchin systems

We show that the Hitchin integrable system for a simple complex Lie group $G$ is dual to the Hitchin system for the Langlands dual group $\lan{G}$. In particular, the general fiber of the connected component $\Higgs_0$ of the Hitchin system for $G$ is an abelian variety which is dual to the corresponding fiber of the connected component of the Hitchin system for $\lan{G}$. The non-neutral connected components $\Higgs_{\alpha}$ form torsors over $\Higgs_0$. We show that their duals are gerbes over $\Higgs_0$ which are induced by the gerbe of $G$-Higgs bundles $\gHiggs$. More generally, we establish a duality between the gerbe $\gHiggs$ of $G$-Higgs bundles and the gerbe $\lan{\gHiggs}$ of $\lan{G}$-Higgs bundles, which incorporates all the previous dualities. All these results extend immediately to an arbirtary connected complex reductive group $\mathbb{G}$.
CHANDRA OBSERVATIONS OF X-RAY-WEAK NARROW-LINE SEYFERT 1 GALAXIES

We present Chandra observations of 17 optically selected, X-ray-weak narrow-line Seyfert 1 (NLS1) galaxies. These objects were optically identified by Williams et al. in the Sloan Digital Sky Survey Early Data Release but were not found in the ROSAT All-Sky Survey (RASS) despite having optical properties similar to RASS-detected NLS1s. All objects in this sample were detected by Chandra and exhibit a range of 0.5-2 keV photon indices Γ = 1.1-3.4. One object was not detected in the soft band but has a best-fit Γ = 0.25 over the full 0.5-8 keV range. These photon indices extend to values far below those normally observed in NLS1s. A composite X-ray spectrum of the hardest objects in this sample does not show any signs of absorption, although the data do not prohibit one or two of the objects from being highly absorbed. We also find a strong correlation between Γ and L1 keV; this may be due to differences in Lbol/LEdd among the NLS1s in this sample. Such variations are seemingly in conflict with the current paradigm that NLS1s accrete near the Eddington limit. Most importantly, this sample shows that strong, ultrasoft X-ray emission is not a universal characteristic of NLS1s; in fact, a substantial number may exhibit weak and/or low-Γ X-ray emission.
Everyday translation: health practitioners’ perspectives on obesity and metabolic disorders in Samoa

Research in Samoa and the diaspora has documented the nutrition transition and related rising metabolic disorders. Research suggests cultural influences, including large body size preference, sedentarism, and dietary patterns, as well as political and economic influences, including changed labor patterns and food dependence, contribute to rising metabolic disorders. This article documents how Samoan health practitioners understand barriers to lifestyle change as primarily cultural rather than structural. They highlight differences between health, framed as individually oriented, and well-being, framed as socially oriented. Drawing from participant observation and semi-structured interviews, this article shows how health practitioners engage in ‘everyday translation’ by aiming to change the meaning of food, body, and wealth. Attention to everyday translation provides insights into the ambivalent ways interviewees identify culture as a barrier to health care. They avoid blaming patients, which has the parad...
The solution structure of the bis-(1,5-diazacyclooctane)nickel(II) ion: an NMR study

Abstract The 300 MHz proton NMR spectrum of bis-(1,5- diazacyclooctane) nickel(II) [Ni(DACO)22+] perchlorate in D2O has been analysed. The vicinal coupling constants indicate that the C3N2Ni six- membered chelate rings exist as rapidly-inverting chair and boat conformations, rather than the completely planar C3N2Ni chelate rings suggested by an earlier crystal structure. The spectrum shows no significant change at low temperature (down to ca. −90 °C), indicating a low barrier for the ring inversion process.
Staggered chiral perturbation theory

Abstract We discuss how to formulate a staggered chiral perturbation theory (SXPT). This amounts to a generalization of the Lee-Sharpe Lagrangian to include more than one flavor ( i. e. , multiple staggered fields), which turns out to be nontrivial. One loop corrections to pion and kaon masses and decay constants are computed as examples in three cases: the quenched, partially quenched, and full (unquenched) case. The results for the one loop mass and decay constant corrections have already been presented in Ref. [1].
The management of a multi-level non-paged memory system

There is a clear tendency for large-scale and, especially time-sharing computer systems to have several levels of random access memory with gradations in access time, degree of addressability, and functional capability. In our configuration at The University of Texas at Austin these are a high-speed magnetic core memory, an extended core memory of magnitude 4 times the size of the main memory, and 4 large, fast disks. An extensive literature has already developed on the management of multi-level systems where the main memory is structured in pages, usually with an extended logical addressing space.
Mars synthetic topographic mapping

Abstract Topographic contour maps of Mars are compiled by the synthesis of data acquired from various scientific experiments of the Mariner 9 mission, including S-band radio-occulation, the ultraviolet spectrometer (UVS), the infrared radiometer (IRR), the infrared interferometer spectrometer (IRIS) and television imagery, as well as Earth-based radar information collected at Goldstone, Haystack, and Arecibo Observatories. The entire planet is mapped at scales of 1:25,000,000 and 1:25,000,000 using Mercator, Lambert, and polar stereographic map projections. For the computation of map projections, a biaxial spheroid figure is adopted. The semimajor and semiminor axes are 3393.4 and 3375.7 km, respectively, with a polar flattening of 0.0052. For the computation of elevations, a topographic datum is defined by a gravity field described in terms of spherical harmonics of fourth order and fourth degree combined with a 6.1-mbar occulation pressure surface. This areoid can be approximated by a triaxial ellipsoid with semimajor axes of A = 3394.6 km and B = 3393.3 km and a semiminor axis of C = 3376.3 km. The semimajor axis A intersects the Martian surface at longitude 105°W. The dynamic flattening of Mars is 0.00525. The contour intercal of the maps is 1 km. For some prominent features where overlapping pictures from Mariner 9 are available, local contour maps at relatively larger scales were also compiled by photogrammetric methods on stereo plotters.
Understanding the benefits and burdens of tube feedings

Tube feedings for patients with severe dementia, metastatic cancer, or stroke present controversial management decisions. Artificial feedings might benefit patients by reversing malnutrition or dehySee also p 1937. dration and prolonging life in patients who are unable to take adequate nutrition by mouth. But Quill's1careful empirical study shows that feeding tubes may not accomplish these goals and may impose significant burdens on patients with severe, irreversible illness. TECHNOLOGY SHOULD BENEFIT THE PATIENT Philosophers have asserted that medicine should benefit the patient, according to the patient's definition of benefit.2Feeding tubes can benefit patients when they provide time to treat underlying medical problems or clarify prognosis or when prolongation of life is feasible and desirable. But Quill found that feeding tubes seldom gained time for underlying reversible conditions to be successfully treated. In only two cases were feeding tubes removed because patients improved. It is questionable whether feeding
The choice between unilateral and multilateral trade liberalization strategies

This paper develops a framework for analyzing the economic costs and benefits of unilateral and multilateral trade liberalization strategies. The interest in this topic is sparked by the apparent dilemma faced by some developing countries in the ongoing Uruguay Round of multilateral trade negotiations (MTNs). An active participation in the MTNs implies that what developing countries have to bargain away is worth something there. If so, it might pay to delay the introduction of unilateral measures in the hope of securing increased access to foreign markets. Deciding on the merits of unilateral and multilateral trade liberalization strategies should involve economic and political factors. This report addresses the economics of this decision and applies the framework to the case of Argentina.
Component cost analysis of large scale systems

Abstract A brief summary of component cost analysis (CCA) is given. CCA provides a means to determine the contribution of each dynamical element of the system in the overall performance metric. Using CCA a theory of cost-equivalent realizations is developed. Cost-equivalent realizations are realizations that have the same value of the performance metric as the original system, and they can be of lower order than Kalman's minimal realization.
Numerical solutions to singular reaction-diffusion equation over elliptical domains

Solid fuel ignition models, for which the dynamics of the temperature is independent of the single-species mass fraction, attempt to follow the dynamics of an explosive event. Such models may take the form of singular, degenerate, reaction-diffusion equations of the quenching type, that is, the temporal derivative blows up in finite time while the solution remains bounded. Theoretical and numerical investigations have proved difficult for even the simplest of geometries and mathematical degeneracies. Quenching domains are known to exist for piecewise smooth boundaries, but often lack theoretical estimates. Rectangular geometries have been primarily studied. Here, this acquired knowledge is utilized to determine new theoretical estimates to quenching domains for arbitrary piecewise, smooth, connected geometries. Elliptical domains are of primary interest and a Peaceman-Rachford splitting algorithm is then developed that employs temporal adaptation and nonuniform grids. Rigorous numerical analysis ensures numerical solution monotonicity, positivity, and linear stability of the proposed algorithm. Simulation experiments are provided to illustrate the accomplishments.
Simple Iron Catalyst for Terminal Alkene Epoxidation

[reaction: see text] A mu-oxo-iron(III) dimer, [((phen)(2)(H(2)O)Fe(III))(2)(mu-O)](ClO(4))(4), is an efficient epoxidation catalyst for a wide range of alkenes, including terminal alkenes, using peracetic acid as the oxidant. Low catalyst loadings, in situ catalyst preparation from common reagents, fast reaction times (<5 min at 0 degrees C), and enhanced reaction performance at high substrate concentrations combine to create a temporally and synthetically efficient procedure for alkene epoxidation.
A flexible nurse scheduling support system

Salaries paid to nursing personnel constitute the largest chunk of a hospital's budget. Therefore, this human resource must be utilized efficiently. Hospitals provide continuous service without the exception of holidays and personal preferences. This causes the nurses' discontent in shift scheduling. And the consequence of this discontent is the nurse shortage. This and the pressures on hospitals to limit costs increase the importance of the nurse scheduling problem. Scheduling nursing personnel in hospitals is very complex due to the variety of conflicting interests or objectives between hospitals and nurses. Also, the demand, which varies widely 24-h a day 7-day a week is skill specific and hard to forecast. In the face of this complexity, the present nurse scheduling models have met with little success. In this paper, we propose a more flexible decision support system that will satisfy the interests of both hospitals and nurses through alternative models that attempt to accommodate flexible work patterns as it integrates time of the day (TOD) and day of the week (DOW) scheduling problems.
Kudzu root: An ancient chinese source of modern antidipsotropic agents

Kudzu (Pueraria lobata) is one of the earliest medicinal plants used in traditional Chinese medicine. It has many profound pharmacological actions including antidipsotropic (antialcohol abuse) activity. Although both the roots and flowers of kudzu, Radix and Flos puerariae, respectively, have been used to treat alcohol abuse safely and effectively in China for more than a millennium, their true efficacy, active constituents, sites and mechanisms of action have never been critically examined. Recently, we have demonstrated that a crude extract of Radix puerariae suppresses the free-choice ethanol intake of ethanol-preferring golden Syrian hamsters and have identified two of its isoflavones, daidzin and daidzein, that account for this effect. Since then, we and other investigators have confirmed these findings in rats that were either trained or genetically bred to prefer and consume large amounts of ethanol. This article summarizes recent progress on the pharmacological and biochemical studies of the antidipsotropic isoflavones isolated from Radix puerariae.
Recent Progress in Enzymatic Synthesis of Sugar Nucleotides

Glycosylation is one of the most important reactions in nature as it results in the formation of glycoconjugates with diverse biological functions. Sugar nucleotides serve as the natural donor molecules for the biosynthesis of such glycoconjugates and other carbohydrates. Furthermore, these donor molecules are also indispensable building blocks for the enzymatic synthesis of carbohydrates in vitro using Leloir-type glycosyltransferases. Given such importance, the biosynthetic pathways of sugar nucleotides have been exploited, enabling the development of both chemical and enzymatic approaches to produce these molecules. A survey of recent progress in enzymatic synthesis of common mammalian sugar nucleotides as well as their derivatives is thus presented. As a popular strategy, conjugation of sugar nucleotide synthesis with glycosyltransfer reactions and in vivo production of sugar nucleotides are also included.
Ion Induced Changes in Phosphoinositide Monolayers at Phisiological Concentrations

Phosphoinositides (PIPs) play a crucial role in many cellular process that occur at the plasma membrane such as calcium release, exocytosis or endocytosis. In order to specifically regulate these functions PIPs must segregate in pools at the plasma membrane. A possible mechanism that could induce and regulate such organization of phosphoinositides is their interaction with bivalent cations. Understanding the physicochemical mechanism that can regulate membrane structure is a crucial step in the development of adaptive biomimetic membrane systems. Using Langmuir monolayers, we investigated the effect of calcium and magnesium on the surface pressure-area/lipid isotherm of monolayer of phosphatidylinositol (PI), phosphatidylinositol bisphosphate (PIP2), dioleoylphosphatidylglycerol (DOPG) and palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). It is found that the decrease of area per lipid, i.e. the increase in aggregation, is mostly dependent on the lipid's head group charge but ion specific. In addition, we discuss changes in free energy and compressibility these monolayer-ion systems.
OEDGE modeling of outer wall erosion in NSTX and the effect of changes in neutral pressure

Abstract Gross erosion from the outer wall is expected to be a major source of impurities for high power fusion devices due to the low redeposition fraction. Scaling studies of sputtering from the all-carbon outer wall of NSTX are reported. It is found that wall erosion decreases with divertor plasma pressure in low/mid temperature regimes, due to increasing divertor neutral opacity. Wall erosion is found to consistently decrease with reduced recycling coefficient, with outer target recycling providing the largest contribution. Upper and lower bounds are calculated for the increase in wall erosion due to a low-field-side gas puff.