cssi/SciSciGPT-SciSciNet huggingface dataset:
A relative version of Connes' $\chi(M)$ invariant and existence of orbit inequivalent actions

We consider a new orbit equivalence invariant for measure-preserving actions of groups on the probability space, $\sigma:G\rightarrow {\rm Aut}(X,\mu)$, denoted by $\chi_0(\sigma;G)$ and defined as the 'intersection' of the 1-cohomology group, H$^1(\sigma,G)$, with Connes' invariant, $\chi(M)$, of the cross product von Neumann algebra, $M=L^\infty(X,\mu)\rtimes_\sigma G$. We calculate $\chi_0(\sigma;G)$ for certain actions of groups of the form $G=H\times K$ with $H$ non-amenable and $K$ infinite amenable and we deduce that any such group has uncountably many orbit inequivalent actions.
Do competition and managed care improve quality

In recent years, the US health care industry has experienced a rapid growth of managed care, formation of networks, and an integration of hospitals. This paper provides new insights about the quality consequences of this dynamic in US hospital markets. I empirically investigate the impact of managed care and hospital competition on quality using in-hospital complications as quality measures. I use random and fixed effects, and instrumental variable fixed effect models using hospital panel data from up to 16 states in the 1992-1997 period. The paper has two important findings: First, higher managed care penetration increases the quality, when inappropriate utilization, wound infections and adverse/iatrogenic complications are used as quality indicators. For other complication categories, coefficient estimates are statistically insignificant. These findings do not support the straightforward view that increases in managed care penetration are associated with decreases in quality. Second, both higher hospital market share and market concentration are associated with lower quality of care. Hospital mergers have undesirable quality consequences. Appropriate antitrust policies towards mergers should consider not only price and cost but also quality impacts.
Acquired and Inherited Lipodystrophies

Lipodystrophies, heterogeneous acquired or inherited disorders characterized by the selective loss of adipose tissue, predispose affected patients to insulin resistance and its attendant complications. This review focuses on the clinical features, underlying pathogenetic mechanisms, and management of various types of acquired and inherited lipodystrophies.
Trade Integration, Market Size, and Industrialization: Evidence from China's National Trunk Highway System

Large-scale transport infrastructure investments connect both large metropolitan centres of production as well as small peripheral regions. Are the resulting trade cost reductions a force for the diffusion of industrial and total economic activity to peripheral regions, or do they reinforce the concentration of production in space? This article exploits China's National Trunk Highway System as a large-scale natural experiment to contribute to our understanding of this question. The network was designed to connect provincial capitals and cities with an urban population above 500,000. As a side effect, a large number of small peripheral counties were connected to large metropolitan agglomerations. To address non-random route placements on the way between targeted city nodes, I propose an instrumental variable strategy based on the construction of least cost path spanning tree networks. The estimation results suggest that network connections have led to a reduction in GDP growth among non-targeted peripheral counties. This effect appears to be driven by a significant reduction in industrial output growth. Additional results present evidence in support of a trade-based channel in the light of falling trade costs between peripheral and metropolitan regions.
Magnetic Reconnection and Turbulent Mixing: From ISM to Clusters of Galaxies

Magnetic reconnection, or the ability of the magnetic field lines that are frozen in plasma to change their topology, is a fundamental problem of magnetohydrodynamics (MHD). We briefly examine the problem starting with the well-known Sweet-Parker scheme, discuss effects of tearing modes, anomalous resistivity and the concept of hyperresistivity. We show that the field stochasticity by itself provides a way to enable fast reconnection even if, at the scale of individual turbulent wiggles, the reconnection happens at the slow Sweet-Parker rate. We show that fast reconnection allows efficient mixing of magnetic field in the direction perpendicular to the local direction of magnetic field. While the idea of stochastic reconnection still requires numerical confirmation, our numerical simulations testify that mixing motions perpendicular to the local magnetic field are up to high degree hydrodynamical. This suggests that the turbulent heat transport should be similar to that in non-magnetized turbulent fluid, namely, should have a diffusion coefficient ∼ V L L, where V L is the amplitude of the turbulent velocity and L is the scale of the turbulent motions. We present numerical simulations which support this conclusion. The application of this idea to thermal conductivity in clusters of galaxies shows that this mechanism may dominate the diffusion of heat and may be efficient enough to prevent cooling flow formation.
Vision and navigation for the Carnegie-Mellon Navlab

A distributed architecture articulated around the CODGER (communication database with geometric reasoning) knowledge database is described for a mobile robot system that includes both perception and navigation tools. Results are described for vision and navigation tests using a mobile testbed that integrates perception and navigation capabilities that are based on two types of vision algorithms: color vision for road following, and 3-D vision for obstacle detection and avoidance. The perception modules are integrated into a system that allows the vehicle to drive continuously in an actual outdoor environment. The resulting system is able to navigate continuously on roads while avoiding obstacles. >
Mechanistic, crystallographic, and computational studies on the catalytic, enantioselective sulfenofunctionalization of alkenes

The stereocontrolled introduction of vicinal heteroatomic substituents into organic molecules is one of the most powerful ways of adding value and function. Although many methods exist for the introduction of oxygen- and nitrogen-containing substituents, the number of stereocontrolled methods for the introduction of sulfur-containing substituents pales by comparison. Previous reports from our laboratories have described sulfenofunctionalizations of alkenes that construct carbon-sulfur bonds vicinal to carbon-oxygen, carbon-nitrogen or carbon-carbon bonds with high levels of diastereospecificity and enantioselectivity. This process is enabled by the concept of Lewis-base activation of Lewis acids, which provides activation of Group 16 electrophiles. To provide a foundation for the expansion of substrate scope and improved selectivities, we have undertaken a comprehensive study of the catalytically active species. Insights gleaned from kinetic, crystallographic and computational methods have led to the introduction of a new family of sulfenylating agents that provide significantly enhanced selectivities.
New Hedonic Estimates of Regional Constant Quality House Prices

Abstract This paper employs a new national data set to estimate constant quality dwelling prices for four regions of the country. The data set, collected by the National Association of Realtors, provides sale prices, locations, and characteristics of 5581 dwellings sold during the years 1986–1992 inclusive. The paper provides the first national hedonic analysis based upon transaction prices of sample dwellings. The estimated equation implies that more than half of dwelling price increases during the period resulted from quality improvements in dwellings.
Boron–Heck Reaction of Cyclic Enaminones: Regioselective Direct Arylation via Oxidative Palladium(II) Catalysis

An oxidative boron–Heck reaction of cyclic enaminones with arylboronic acids is reported. This protocol provides a regioselective arylation at the C6 position of cyclic enaminones. When an N-carbamylated cyclic enaminone was employed, a switch to a conjugate addition reaction occurred in the presence of acid.
SOME GEOMETRIC GROUPS WITH RAPID DECAY

We explain simple methods to establish the property of Rapid Decay for a number of groups arising geometrically. Those lead to new examples of groups with the property of Rapid Decay, notably including non-cocompact lattices in rank one Lie groups.
Packet Chaining: Efficient Single-Cycle Allocation for On-Chip Networks

This paper introduces packet chaining, a simple and effective method to increase allocator matching efficiency and hence network performance, particularly suited to networks with short packets and short cycle times. Packet chaining operates by chaining packets destined to the same output together, to reuse the switch connection of a departing packet. This allows an allocator to build up an efficient matching over a number of cycles, like incremental allocation, but not limited by packet length. For a 64-node 2D mesh at maximum injection rate and with single-flit packets, packet chaining increases network throughput by 15% compared to a conventional single-iteration separable iSLIP allocator, outperforms a wavefront allocator, and gives comparable throughput with an augmenting paths allocator. Packet chaining achieves this performance with a cycle time comparable to a single-iteration separable allocator. Packet chaining also reduces average network latency by 22.5%. Finally, packet chaining increases IPC up to 46% (16% average) for application benchmarks because short packets are critical in a typical cache-coherent CMP. These are considerable improvements given the maturity of network-on-chip routers and allocators.
THE MECHANISM OF OXYGEN REDUCTION ON ZINC

Abstract A systematic investigation of the products of oxygen reduction and their possible effects on the failure of coated systems which was initiated for model steel systems is here continued for the zinc/alkaline electrolyte interface. The analysis of the experimental rotating ring-Zn disc electrode data allowed the pathways of oxygen reduction to be determined as a function of the state of metal surface. Peroxyl ions were found to be stable products of oxygen reduction at oxide covered zinc surfaces, both in the passive and prepassive potential regions. Only at bare metal surfaces, does oxygen reduction lead exclusively to hydroxyl ions.
Hypermultiplet moduli space and string compactification to three dimensions

Abstract We study the hypermultiplet moduli space of the type II string compactified on a Calabi-Yau space X . We do this by using IIA/IIB duality in a compactification of the same theory on X × S 1 and by using recent results on three dimensional field theory.
Genetic variation, climate models and the ecological genetics of Larix occidentalis

Abstract Provenance tests of 143 populations of Larix occidentalis revealed genetic differentiation for eight variables describing growth, phenology, tolerance to spring frosts, effects of Meria laricis needle cast, and survival. Geographic variables accounted for as much as 34% of the variance among Rocky Mountain populations. Patterns of genetic variation were dominated by the effects of latitude and elevation, with populations from the north and from high elevations having the lowest growth potential, the least tolerance to the needle cast, and the lowest survival. However, the slope of the geographic clines was relatively flat. Populations in the same geographic area, for instance, need to be separated by about 500 m in elevation before genetic differentiation can be expected. Regression models using geographic predictors were developed to describe variation in ten climatic variables from 192 weather stations that best represented the Rocky Mountain distribution of L. occidentalis . Values of R 2 ranged from 0.42 to 0.92 and were higher for temperature than for precipitation variables. Using climatic effects predicted for each provenance to describe genetic variation produced values of R 2 between 0.15 and 0.27 which accounted for nearly as much (68–100%) of the genetic variance as had geographic variables. The analyses suggested that genetic differentiation was controlled primarily by the relative mildness of the climate. Secondary effects of precipitation were implicated for variables measuring the impact of Meria needle cast and survival.
Adaptive Optics Observations of Vega: Eight Detected Sources and Upper Limits to Planetary‐Mass Companions

From adaptive optics observations with the Palomar 5 m telescope we place upper limits on the masses of any planetary companions located between ~30 and 230 AU away from Vega, where our data are sensitive to depths ranging from H = 12.5-19.0 mag fainter than Vega itself. Our observations cover a plus-shaped area with two 25″ × 57″ elements, excluding 7″ × 7″ centered on the star. We have identified two double and four single point sources. These projected companions are 14.9-18.9 mag fainter than Vega and, if physically associated, would have masses ranging from 4 to 35 M_J and orbital radii of 170-260 AU. Recent simulations of dusty rings around Vega predict the presence of a perturbing body with a mass of less than 2-3 M_J and an orbital radius of ~40-100 AU, and more massive (≾10 M_J) planets cannot be excluded. None of the detected objects are this predicted planet. Based on a color-magnitude, spectroscopic, and proper motion analysis, all objects are consistent with being background sources. Given the glare of Vega, a 2 M_J object near the expected orbital radii would not have been visible at the 5 σ level in our data, though any brown dwarf with mass greater than 10 M_J could have been seen at a separation greater than 80 AU.
Can hadronic rescattering explain the large elliptic flow and small HBT radii seen at RHIC

Results from the data obtained in the first physics run of the Relativistic Heavy Ion Collider (RHIC) have shown surprisingly large elliptic flow and surprisingly small HBT radii. The present work shows that a thermal model + hadronic rescattering calculation can explain both elliptic flow and HBT results from RHIC. The calculation requires a very early hadronization time of about 1 fm/c after the initial collision of the nuclei.
Optimized loading for particle-in-cell gyrokinetic simulations

The problem of particle loading in particle-in-cell gyrokinetic simulations is addressed using a quadratic optimization algorithm. Optimized loading in configuration space dramatically reduces the short-wavelength modes in the electrostatic potential that are partly responsible for the nonconservation of total energy; further, the long-wavelength modes are resolved with good accuracy. As a result, the conservation of energy for the optimized loading is much better that the conservation of energy for the random loading. The method is valid for any geometry and can be coupled to optimization algorithms in velocity space. PACS Nos.: 52.35.Py, 52.30.Jb, 52.55.Fa
Electrophilic Cyclizations of 2-Fluoroalk-3-yn-1-ones: Room-Temperature Synthesis of Diversely 2,5-Disubstituted 3,4-Fluorohalofurans

A 5-endo-dig halocyclization of 2-fluoroalk-3-yn-1-ones with the use of N-iodo- and N-bromosuccinimide, in the presence of gold chloride/zinc bromide (5:20 mol-%, dichloromethane), under ambient conditions, provides a facile method for the synthesis of 2,5-disubstituted 3-bromo-4-fluoro- and 3-fluoro-4-iodofurans. The sequential procedure starts at monofluorination of the alk-1-en-3-yn-1-yl silyl ethers with Selectfluor and proceeds with good overall yields (62-78%).
The Monte Carlo technique applied to radiative transfer.

Abstract A general review is given of the application of the Monte Carlo method to the numerical calculations of non-equilibrium radiation transport. With the aid of a general flow chart, the various steps required in such Monte Carlo calculations are detailed. Advanced techniques which improve efficiency of calculations such as weighting and biasing are also discussed. Although specific results are not given in the text, references to recent Monte Carlo calculations of radiation transport are included.
The dependence of hurricane intensity on climate

Tropical cyclones rank with earthquakes as the major geophysical causes of loss of life and property1. It is therefore of practical as well as scientific interest to estimate the changes in tropical cyclone frequency and intensity that might result from short-term man-induced alterations of the climate2. In this spirit we use a simple Carnot cycle model to estimate the maximum intensity of tropical cyclones under the somewhat warmer conditions expected to result from increased atmospheric CO2 content. Estimates based on August mean conditions over the tropical oceans predicted by a general circulation model with twice the present CO2 content yield a 40–50% increase in the destructive potential of hurricanes.
Concise Synthesis of (−)-Nakadomarin A†

The beautiful orchestration of new methods and synthesis design was instrumental to the very efficient synthesis of the manzamine alkaloid (-)-nakadomarin A. In only six operations, the two relatively simple compounds shown were converted into the hexacyclic natural product.
Kähler manifolds with Ricci curvature lower bound

On Kahler manifolds with Ricci curvature bounded from below, we establish some theorems which are counterparts of some classical theorems in Riemannian geometry, for example, Bishop-Gromov’s relative volume comparison, Bonnet-Meyers theorem, and Yau’s gradient estimate for positive harmonic functions. The tool is a Bochner type formula reflecting the Kahler structure.
Multistage investment, systematic risk premium and CAPM beta: empirical evidence from product development

Recent theoretical literature suggests that the magnitude of the systematic risk premium for a multistage investment project is subject to various forces that may cause the premium to change across stages. To test this hypothesis, I investigate whether Capital Asset Pricing Model (CAPM) beta differs by product development stage in the biotechnology industry. To this end I estimate CAPM beta for various stages of drug development using Full-Information Beta (FIB) technique. Findings indicate that early stage drug development projects have higher CAPM beta than drugs in later stages of development or in production and marketing. The beta appears to decrease monotonically as a project approaches completion.
A Thermal Dehydrogenative Diels–Alder Reaction of Styrenes for the Concise Synthesis of Functionalized Naphthalenes

Functionalized naphthalenes are valuable building blocks in many important areas. A microwave-assisted, intramolecular dehydrogenative Diels–Alder reaction of styrenyl derivatives to provide cyclopenta[b]naphthalene substructures not previously accessible using existing synthetic methods is described. The synthetic utility of these uniquely functionalized naphthalenes was demonstrated by a single-step conversion of one of these cycloadducts to a fluorophore bearing a structural resemblance to Prodan.
A Combined Surface Science and Electrochemical Study of Tungsten Carbides as Anode Electrocatalysts

An effective anode electrocatalyst in direct methanol fuel cell (DMFC) should have high activity for the oxidation of methanol and the decomposition of water, while remaining stable under the relatively harsh anode environment. Although the Pt/Ru bimetallic alloy is currently the most effective anode electrocatalyst, both Pt and Ru are expensive due to limited supplies and both are susceptible to CO poisoning. Consequently, the discovery of less expensive and more CO tolerant alternatives to the Pt/Ru catalysts would help facilitate the commercialization of DMFC. In this paper we will discuss the possibility of using tungsten carbides (WC) and Pt-modified WC as potential anode electrocatalysts in DMFC. We will provide an overview of our recent work, using a combined approach of fundamental surface science studies and in-situ electrochemical evaluation of the activity and stability of tungsten carbides. We will demonstrate the feasibility to bridge fundamental surface science studies on single crystals with the electrochemical evaluation on polycrystalline WC films. We will also discuss the synergistic effect by supporting low coverages of Pt on the WC substrate to further enhance the electrochemical performance of WC.
Pulsed Laser Polymerization at Low Conversions: Broadening and Chain Transfer Effects

Pulsed laser polymerization (PLP) is widely employed to masure propagation rate coefficients k p in free radical polymerization. Various properties of PLP have been established in previous works, mainly using numberical methods. The objective of this paper is to obtain analytical results. We obtain the most general analytical solution for the dead chain molecular weight distribution (MWD) under low conversion conditions which has been hitherto obtained Simultaneous disproportionation and combination termination processes are treated. The hallmarks of PLP are the dead MWD discontinuities located at integer multiples of n 0 =k p t 0 C M , where t 0 is the laser period and C M is the monomer concentration. We show that chain transfer reduces thier amplitude by factors e -C u Ln 0, consistent with numerical results obtained by other workers. Here c tr is the chain transfer coefficient and Ln 0 (L = integer) are the discontinuity locations. Additionally, transfer generates a small amplitude continuous contribution to the MWD, These results generalize earlier analytical results which were obtained for the case of disproportionation only. We also considered two classes of and (ii) intrinsic broadening by the MWD measuring equipment (typically gel permeation chromatography, GPC). Broadening smoothes the MWD discontinuities. Under typical PLP experimental conditions, the associated inflection points are very close to the discontinuities of the unbroadened MWD Previous numerical works have indicated that the optimal procedure is to use the inflection point to infer k p . We prove that this is a correct procedure provided the GPC resolution σ is better than n 1/2 0. Otherwise this underestimates Ln 0 by an amount of order σ 2 /n 0 .
Some cyclic covers of complements of arrangements

Motivated by the Milnor fiber of a central arrangement, we study the cohomology of a family of cyclic covers of the complement of an arbitrary arrangement. We give an explicit proof of the polynomial periodicity of the Betti numbers of the members of this family of cyclic covers.
DISSIPATION AND HEATING IN SUPERSONIC HYDRODYNAMIC AND MHD TURBULENCE

We study energy dissipation and heating by supersonic MHD turbulence in molecular clouds using Athena, a new higher order Godunov code. We analyze the dependence of the saturation amplitude, energy dissipation characteristics, power spectra, sonic scaling, and indicators of intermittency in the turbulence on factors such as the magnetic field strength, driving scale, energy injection rate, and numerical resolution. While convergence in the energies is reached at moderate resolutions, we find that the power spectra require much higher resolutions that are difficult to obtain. In a 10243 hydro run, we find a power law relationship between the velocity dispersion and the spatial scale on which it is measured, while for an MHD run at the same resolution, we find no such power law. The time variability and temperature intermittency in the turbulence both show a dependence on the driving scale, indicating that numerically driving turbulence by an arbitrary mechanism may not allow a realistic representation of these properties. We also note similar features in the power spectrum of the compressive component of velocity for supersonic MHD turbulence as in the velocity spectrum of an initially spherical MHD blast wave, implying that the power law form does not rule out shocks, rather than a turbulent cascade, playing a significant role in the regulation of energy transfer between spatial scales.
Ge–GaAs(110) interface formation

The heterojunction chemistry for Ge grown by molecular beam epitaxy (MBE) on in situ cleaved GaAs exhibits significant interdiffusion in short times at growth temperatures T G of 430°C (significantly lower critical T G than that reported for moderate-vacuum physical vapor deposition). This results in profound changes in the electronic properties of the interface as probed by synchrotron-radiation-excited 3d core electron photoemission. Even when there is significant alloying of the two lattice-matched semiconductors, there is nearly equal probability for Ge to bond to either a Ga or an As atom at the initial stage. As Ge becomes the dominant species, we find As preferentially diffusing toward the Ge side of the junction. This As is distributed throughout the overlayer in contrast to metal-semiconductor interface formation where the diffusing constituent resides only on the free, growing surface. We show that these behaviors are consistent with the kinetic and thermodynamic properties of the atomic species. The valence band discontinuity is negligible over atomic dimensions, while for an abrupt interface (T G = 350°C) we measure ΔE v = 0.7± 0.3 0.05 eV. The photoemission changes character rapidly with temperature, indicating an activation barrier for the diffusion below which simple expressions for attenuation of the photoelectrons by electron—electron scattering are applicable. In that case we deduce an escape depth of 7.0 ±0.5 A, indicating uniform growth of Ge, with composition changing abruptly from GaAs over ~1 bond length in the (110) direction. A negligible (<0.2 eV) localized interface dipole layer is formed in the process.
Intelligent Flight Trajectory Generation to Maximize Safe Outcome Probability after a Distress Event

A flight trajectory generation method called the distressed-aircraft-recovery technique for maximum safe-outcome probability (DART_MSOP), based on integration of three new algorithms, is developed that maximizes safe-outcome probability after a distress event by incorporating an abort airport together with a model of current aircraft dynamics. Several abort-probability models are studied under various constraints. The first new algorithm, a statistical-based initial-turn-determination algorithm, is developed to advise pilots to a reachable best landing site immediately after the distress event and before using the second new algorithm, a high-fidelity flight trajectory generation algorithm. A third new algorithm determines the flight maneuver for guidance of a perpetual-turning-attitude aircraft to fly the trajectory generated by the second algorithm. The third algorithm is only used if the aircraft has stuck controls or a similar malfunction that generates a nonzero amount of bank angle and causes the aircraft to turn only in one direction. As a three-dimensional high-fidelity algorithm, the second algorithm considers the probability of an abort to increase overall survivability by minimizing expected flight-path length as it shapes the trajectory. The performance of this new intelligent flight trajectory determination method DART_MSOP is evaluated using a case study based on a hypothetical in-flight distressed transport aircraft in northern California. Numerical simulations include variable failure rates to simulate different in-flight distress conditions, and multiple fixes along the path to accommodate realistic trajectories. DART_MSOP intelligent flight trajectory determination method should increase aviation safety if these algorithms are implemented in aircraft avionics systems.
From 0-branes to torons

Abstract The moduli space of 0-branes on T 4 gives a prediction for the moduli space of torons in U ( n ) super-Yang-Mills theory which preserve 16 supersymmetries. The 0-brane number corresponds to the greatest common denominator of the rank n , magnetic fluxes and the instanton number. This prediction is derived using U -duality. We explicitly check this prediction by analyzing U ( n ) bundles with non-zero first as well as second Chern classes. The argument is extended to deduce the moduli space of torons which preserve 8 supersymmetries. Parts of the discussion extend naturally to T 2 and T 3 . Some of the U -dualities involved are related to Lorentz boosts along the eleventh direction in M-theory.
Intramolecular additions of allylsilanes in triquinane synthesis. Studies directed toward the total synthesis of (±)-hirsutene

Abstract The straightforward construction of the cis , anti , cis -cyclopenta[ a ]pentalene skeleton characteristic of (±)-hirsutene was achieved via the intramolecular addition of two functionalized cyclopentane rings linked by a one-carbon tether.
Facile Preparation of the Methyl Acetal of Methyl Phenylglyoxylate

Abstract The methyl acetal of methyl phenylglyoxylate has been prepared from halophenylethynes, N-iodosuccinimide and catalytic amounts of (hydroxy(p-tosyloxy)iodo)benzene or p-toluenesulfcnic acid in methanol at room temperature.
On the Structure of Eigenfunctions Corresponding to Embedded Eigenvalues of Locally Perturbed Periodic Graph Operators

The article is devoted to the following question. Consider a periodic self-adjoint difference (differential) operator on a graph (quantum graph) G with a co- compact free action of the integer lattice \(\mathbb{Z}^{n}\). It is known that a local perturbation of the operator might embed an eigenvalue into the continuous spectrum (a feature uncommon for periodic elliptic operators of second order). In all known constructions of such examples, the corresponding eigenfunction is compactly supported. One wonders whether this must always be the case. The paper answers this question affirmatively. What is more surprising, one can estimate that the eigenmode must be localized not far away from the perturbation (in a neighborhood of the perturbation’s support, the width of the neighborhood dependent upon the unperturbed operator only). The validity of this result requires the condition of irreducibility of the Fermi (Floquet) surface of the periodic operator, which is known in some cases and is expected to be satisfied for periodic Schrodinger operators.
Human Carcinogenesis, the New Genetics, and the Practicing Pathologist

The current explosion in medical information has broadened the range of op portunities for anatomic pathologists while threatening their identity as medical consultants. As the complexities of processes such as human carcinogenesis are clarified, the temptation to bypass traditional methods of transferring informa tion from the research bench to the bedside should be resisted. Patients continue to expect wisdom, perspective, and judgment from their doctors and these func tions have not been abrogated by molecular technology in the information age. Int J Surg Pathol 10(1):1-5, 2002
Open spin chains in super Yang-Mills at higher loops: some potential problems with integrability

The super Yang-Mills duals of open strings attached to maximal giant gravitons are studied in perturbation theory. It is shown that non-BPS baryonic excitations of the gauge theory can be studied within the paradigm of open quantum spin chains even beyond the leading order in perturbation theory. The open spin chain describing the two loop mixing of non-BPS giant gravitons charged under an su(2) of the so(6) R symmetry group is explicitly constructed. It is also shown that although the corresponding open spin chain is integrable at the one loop order, there is a potential breakdown of integrability at two and higher loops. The study of integrability is performed using coordinate Bethe ansatz techniques.
DIFFUSIVE COSMIC-RAY ACCELERATION IN SAGITTARIUS A*

Together, Fermi-LAT and HESS have revealed the presence of an unusual GeV-TeV source coincident with Sgr A* at the Galactic center. Its high-energy emission appears to be bimodal, hinting at an energizing process more sophisticated than mere shock acceleration. It has been suggested that this may be evidence of strong, rapid variability, as required if Sgr A*'s emission were responsible for the fluorescent X-ray echoes detected in nearby molecular clouds. In this Letter, however, we show that stochastic acceleration in a more realistic two-phase environment surrounding the central black hole can accommodate Sgr A*'s high-energy spectrum quite well. We therefore suggest that the Fermi-HESS data alone do not necessarily provide evidence for strong variability in Sgr A*.
On lubrication flows in geometries with zero local curvature

The familiar examples of lubrication theory for the approximate analysis of the motion of cylindrical and spherical particles near boundaries takes advantage of the local parabolic shape near contact. We generalize these studies to particles and boundaries of more general shape, which have the feature that the curvature is zero at the point of minimum separation in the gap. Order-of-magnitude estimates and detailed solutions are given. The translation of such a close-fitting object in a circular tube, and the pressure-driven flows between two surfaces with zero curvature at minimum separation and in a saddle-shaped channel, are considered in a similar fashion.
Reputation and the control of pollution

This paper investigates the effectiveness of reputation in inducing a polluting firm to self-regulate its emissions when consumers have imperfect information. In particular, we ask to what extent must consumers reward and punish the firm before it chooses self-regulation as its dominant strategy? We find that if payoffs in the stage game are such that both the consumer and the polluting firm have beliefs that are consistent with each others' behaviors, then the firm has a positive probability of playing clean in each period of a finite game. Further, we find that a weak reward/punishment scheme may have an adverse effect on the environment, and that there are both environmental and welfare gains associated with strengthening the scheme.
Asymmetric synthesis of homopropargylic alcohols from aldehydes and allenyltri-n-butylstannane

Abstract The reaction of allenyltri- n -butylstannane with aldehydes and a chiral Lewis acid prepared from (R)-BINOL and Ti(O- i -Pr) 4 gives homopropargylic alcohols with 82 ->99% ee.
Size and Shape Control of Metal Nanoparticles for Reaction Selectivity in Catalysis

A nanoparticle with well-defined surfaces, prepared through colloidal chemistry, enables it to be studied as a model heterogeneous catalyst. The colloidal synthetic approach provides versatile tools to control the size and shape of nanoparticles. Traditional nucleation and growth mechanisms have been utilized to understand how nanoparticles can be uniformly synthesized and unprecedented shapes can be controlled. Now, the size of metal particles can be controlled to cluster regimes by using dendrimers. By using seeds and foreign atoms, specific synthetic environments such as seeded growth and crystal overgrowth can be induced to generate various shaped mono- or bi-metallic, core/shell, or branched nanostructures. For green chemistry, catalysis in 21st century is aiming for 100 % selectivity to produce only one desired product at high turnover rates. Recent studies on nanoparticle catalysts clearly demonstrate size and shape dependent selectivity in many catalytic reactions. By combining in situ surface characterization techniques, real-time monitoring of nanoparticles can be performed under reaction environments, thus identifying several molecular factors affecting catalytic activity and selectivity.
Harmonic Functions, Entropy, and a Characterization of the Hyperbolic Space

Let (Mn,g) be a compact Riemannian manifold with Ric ≥−(n−1). It is well known that the bottom of spectrum λ0 of its universal covering satisfies λ0≤(n−1)2/4. We prove that equality holds iff M is hyperbolic. This follows from a sharp estimate for the Kaimanovich entropy.
Hybrid concurrency control for abstract data types

Abstract Databases and other transaction-processing systems use concurrency control and recovery algorithms to ensure that transactions are atomic (i.e., serializable and recoverable). We present a new algorithm based on locking that permits more concurrency than existing commutativity-based algorithms. The algorithm exploits type-specific properties of objects; necessary and sufficient constraints on lock conflicts are derived directly from a data type specification. In addition, the algorithm permits operations to be both partial and non-deterministic, and it permits the lock mode for an operation to be determined by its results as well as its name and arguments. We give a complete formal description of the algorithm, encompassing both concurrency control and recovery, and prove that the algorithm satisfies hybrid atomicity, a local atomicity property that combines aspects of static and dynamic atomic algorithms. We also show that the algorithm is optimal in the sense that no hybrid atomic locking scheme can permit more concurrency.
Kinetics of drug action in disease states. XXI. Relationship between drug infusion rate and dose required to produce a pharmacologic effect

Computer simulations were performed to determine if the threshold dose of an infused drug (rather than the drug concentration in the biophase at onset of action) can be a suitable index for pharmacodynamic investigations as proposed by others. A two-compartment pharmacokinetic model with drug elimination from the central compartment was used for the simulations. Drug was administered into the central compartment by a constant-rate infusion, and concentrations in the central and peripheral compartments were calculated as a function of time. The pharmacologic effect was assumed to be reversible and to occur at a defined concentration (the effective concentration) in one or the other compartment. The dose required to produce an effective concentration (threshold dose) was determined as a function of infusion rate. The relationship between infusion rate and the dose required to produce an effective concentration in the peripheral compartment was found to be affected by drug distribution and elimination kinetics and by the effective concentration. The infusion rate-dose relationship showed a dose minimum at an infusion rate which others have designated as the "optimal dose rate" and have used for pharmacodynamic studies. No such minimum occurred for pharmacologic effects associated directly with drug concentrations in the central compartment. Since optimum dose rate and threshold dose are affected by both pharmacokinetic and pharmacodynamic alterations, it is concluded that this method (which avoids determination of drug concentrations) is not generally suitable for quantitative pharmacodynamic investigations.
Efficient broadcast and multicast on multistage interconnection networks using multiport encoding

This paper proposes anew approach for implementing fast multicast and broadcast in unidirectional and bidirectional multistage interconnection networks (MINs) with multiport encoded multidestination worms. For a MIN with n stages, such worms use n header flits each. One flit is used for each stage of the network and it indicates the output ports to which a multicast message needs to be replicated. A multiport encoded worm with (d/sub 1/, d/sub 2/..., d/sub n/, 1/spl les/d/sub i//spl les/k) degrees of replication for the respective stages is capable of covering (d/sub 1//spl times/d/sub x//spl times/.../spl times/d/sub n/) destinations with a single communication start-up. In this paper, a switch architecture is proposed for implementing multidestination worms without deadlock. Three grouping algorithms of varying complexity are presented to derive the associated multiport encoded worms for a multicast to an arbitrary set of destinations. Using these worms, a multinomial tree-based scheme is proposed to implement the multicast. This scheme significantly reduces broadcast/multicast latency compared to schemes using unicast messages. Simulation studies for both unidirectional and bidirectional MIN systems indicate that improvement in broadcast/multicast latency up to a factor of four is feasible using the new approach. Interestingly, this approach is able to implement multicast with reduced latency as the number of destinations increases beyond a certain number. Compared to implementing unicast messages, this approach requires little additional logic at the switches. Thus, the scheme demonstrates significant potential for implementing efficient collective communication operations on current and future MIN-based systems.
Macromodular computer systems

The amount of logically irrelevent engineering detail inherent in the design and construction of a computer system is great. As a result, the task of creating a system based on the use of present techniques is so difficult and time-consuming that the number of different systems that can be put into use for evaluation and study by any one group of workers is small. This is unfortunate as we are thereby denied the opportunity to develop that insight into logical organization which can grow out of a working familiarity with many diverse forms. What is needed is a set of relatively simple, easily inter-connected modules from which working systems can be readily assembled for evaluation and study. With such a set, both the designer and user would be able to try out potentially powerful and novel structures on a very large scale, adjusting and improving the systems as needed. Once a design has been realized and its value established, it could then be reworked into tighter engineering form for maximum efficiency and for production by automatic wiring and fabrication techniques, and the experimental units made available for further studies or returned to "inventory" in the manner proposed by Estrin.
Non-Einstein geometries in chiral gravity

We analyze the asymptotic solutions of Chiral Gravity (Topologically Massive Gravity at μl= 1 with Brown-Henneaux boundary conditions) focusing on non-Einstein metrics. A class of such solutions admits curvature singularities in the interior which are reflected as singularities of the corresponding linear solutions. A non-linear solution is found exactly. The back-reaction induces a repulsion of geodesics and a shielding of the singularity by an event horizon but also introduces closed timelike curves.
An oblique end-tab design for testing off-axis composite specimens

Abstract A new oblique-shaped end-tab was investigated for use in testing off-axis coupon specimens. This tab is able to ensure the axial displacement that is necessary in off-axis specimens under uniaxial loading. The explicit expression of the oblique angle was obtained as a function of the off-axis angle and composite properties. Finite element analysis and experiments were performed to evaluate the effectiveness of the oblique tab. Both results indicated that the oblique tab is more suitable than the conventional rectangular tab for uniaxial off-axis testing.
Sandwich-type germanotungstates: structure and magnetic properties of the dimeric polyoxoanions [M4(H2O)2(GeW9O34)2]12 - (M = Mn2+, Cu2+, Zn2+, Cd2+).

The novel dimeric germanotungstates [M4(H2O)2(GeW9O34)2]12- (M = Mn2+, Cu2+, Zn2+, Cd2+) have been synthesized and characterized by IR spectroscopy, elemental analysis, magnetic measurements, and 183W-NMR spectroscopy. X-ray single-crystal analyses were carried out on Na12[Mn4(H2O)2(GeW9O34)2]·38H2O (Na12-1), which crystallizes in the monoclinic system, space group P21/n, with a = 13.0419(8) A, b = 17.8422(10) A, c = 21.1626(12) A, β = 93.3120(10)°, and Z = 2; Na11Cs2[Cu4(H2O)2(GeW9O34)2]Cl·31H2O (Na11Cs-2) crystallizes in the triclinic system, space group P1, with a = 12.2338(17) A, b = 12.3833(17) A, c = 15.449(2) A, α = 100.041(2)°, β = 97.034(2)°, γ = 101.153(2)°, and Z = 1; Na12[Zn4(H2O)2(GeW9O34)2]·32H2O (Na12-3) crystallizes in the triclinic system, space group P1, with a = 11.589(3) A, b = 12.811(3) A, c = 17.221(4) A, α = 97.828(6)°, β = 106.169(6)°, γ = 112.113(5)°, and Z = 1; Na12[Cd4(H2O)2(GeW9O34)2]·32.2H2O (Na12-4) crystallizes also in the triclinic system, space group P1, with a = 11.692...
AdS3 black holes and a stringy exclusion principle

The duality relating near-horizon microstates of black holes obtained as orbifolds of a subset of AdS3 to the states of a conformal field theory is analyzed in detail. The SL(2,R)L?SL(2,R)R invariant vacuum on AdS3 corresponds to the NS-NS vacuum of the conformal field theory. The effect of the orbifolding is to produce a density matrix, the temperature and entropy of which coincide with the black hole. For string theory examples the spectrum of chiral primaries agrees with the spectrum of multi-particle BPS states for particle numbers less than of order the central charge. An upper bound on the BPS particle number follows from the upper bound on the U(1) charge of chiral primaries. This is a stringy exclusion principle which cannot be seen in perturbation theory about AdS3.
Projection and assembly method for multibody component model reduction

The problem addressed is that of obtaining reduced-order component models for use in simulating the dynamics of a multibody system. In certain cases, nonlinear system models may be constructed using linear dynamic models for each component, but allowing large angle motion between components. Without some form of model reduction, system models constructed in this manner may be too large for use in control system design and simulation trades. This paper analyzes one method of component model reduction that allows systems level requirements (e.g., capturing the effect of body 1 reaction wheel noise on body 2 camera pointing) to aid in the selection of the reduced-order component models. Briefly stated, important modes are selected at the system level and projected onto the components, and reduced-order components are then assembled into a reduced-order system model that retains the projected modes.
Structure and physical properties of CeSbTe

Abstract The structure of CeSbTe was determined by the Rietveld refinement method using powder X-ray diffraction ( R p =6.22% and wR p =8.74%). CeSbTe adopts the PbFCl structure type and crystallizes in the space group Pnma (No. 62) of the orthorhombic system with Z =4 and a =19.0404(6) A, b =4.3520(1) A, c =4.3660(2) A, V =361.78(2) A 3 . It can be viewed as a layered compound which contains an Sb −1 layer distorted from a perfect square net into zig-zag chains. Both its crystallographic and electronic structure indicate a 2-D character. Based on transport properties and band structure calculations, CeSbTe is a metal with a low carrier concentration. Additionally, it exhibits paramagnetic behavior typical of Ce 3+ .
Wind tunnel testing of a novel wingsuit design

Abstract A wingsuit is a special suit that is worn to allow the user to fly after jumping off of a high cliff. The wingsuit creates an airfoil shape by adding wings of material between the arms and the sides as well as a tail consisting of material between the legs. The wingsuit allows for the creation of lift and thus human flying. A new and novel wingsuit design is proposed based on the design of a delta wing aircraft. This new wingsuit has material leading from the side of the head and connecting to the top of the arms, extending the area of the forward wing. Using a mannequin in a wind tunnel, the aerodynamic performance of the new wingsuit will be measured and compared to that of the current wingsuit design. The results show that the redesigned wingsuit had a lower lift-to-drag ratio in most testing scenarios. The decrease in lift-to-drag ratio was due to the combination of an increased lift and a higher increased drag.
Earnings Forecasts and the Information Contained in Spinoff Announcements

This study examines spinoff announcements in conjunction with financial analysts’ forecasts of earnings. The analysis shows that spinoff announcement abnormal returns are significantly related to the firm's information environment as proxieci by financial analysts’ earnings prediction errors. The findings also indicate that analysts significantly increase their short-term earnings forecasts in response to spinoffs, but do not significantly revise their long-term earnings forecasts. However, the earnings revisions are not significantly different across prediction error groups, which confirms that spinoff-related abnormal returns cannot be attributed solely to expected performance gains.