cssi/SciSciGPT-SciSciNet huggingface dataset:
HST/STIS UV Spectroscopy of Two Quiescent X-Ray Novae: A0620–00 and Centaurus X-4

In 1998 we made UV spectroscopic observations with HST/STIS of A0620-00 and Cen X-4, which are two X-ray novae (also known as soft X-ray transients). These binary systems are similar in all respects except that the former contains a black hole and the latter contains a neutron star. A UV spectrum (1700-3100 A) is presented for the quiescent state of each system in the context of previously published UV/optical and X-ray data. The nonstellar, continuum spectrum of black hole A0620-00 has a prominent UV/optical peak centered at ~3500 A. In contrast the spectrum of neutron star Cen X-4 lacks a peak and rises steadily with frequency over the entire UV/optical band. In the optical, the two systems are comparably luminous. However, black hole A0620-00 is ~6 times less luminous at 1700 A, and ~40 times less luminous in the X-ray band. The broadband spectrum of A0620-00 is discussed in terms of the advection-dominated accretion flow model.
The ethics of play, leisure, and recreation in the twentieth century, 1900–1983

Abstract The association between play, leisure, recreation, value, and free choice leads to the problem of ethics. The purpose of this study was to describe the absolute ultimate end (the highest good) and its relation to play, leisure, and recreation in the twentieth century. This problem was approached by perusing literature from the period 1900 through 1983. Writers were organized by category and period, accompanied by explanation of how play, leisure, and recreation were related to the highest good. Eighty writers considered the question of the absolute ultimate end. Nine categories were discerned, dominated by divine ends and happiness. Play, leisure, and recreation were variously connected with the ultimate ends as both ends and means. Additionally, the practical implications of ethics are discussed using several examples. A partnership between science and philosophy is recommended for further study of ethics. Philosophy of leisure, however, must be revived for this alliance to
Analogs of the m -function in the theory of orthogonal polynomials on the unit circle

We show that the multitude of applications of the Weyl-Titchmarsh m-function leads to a multitude of different functions in the theory of orthogonal polynomials on the unit circle that serve as analogs of the m-function.
Averages of Characteristic Polynomials in Random Matrix Theory

We compute averages of products and ratios of characteristic polynomials associated with orthogonal, unitary, and symplectic ensembles of random matrix theory. The Pfaffian/determinantal formulae for these averages are obtained, and the bulk scaling asymptotic limits are found for ensembles with Gaussian weights. Classical results for the correlation functions of the random matrix ensembles and their bulk scaling limits are deduced from these formulae by a simple computation. We employ a discrete approximation method: the problem is solved for discrete analogues of random matrix ensembles originating from representation theory, and then a limit transition is performed. Exact Pfaffian/determinantal formulae for the discrete averages are proven using standard tools of linear algebra; no application of orthogonal or skew-orthogonal polynomials is needed. © 2005 Wiley Periodicals, Inc.
Non-local symmetries for Yang-Mills theories and their massive counterparts in two and three dimensions

We identify a non-local symmetry for Yang-Mills theories in 1 + 1 and 2 + 1 spacetime dimensions. The symmetry mixes a vector current constructed out of the gauge field with the gauge field itself. We specify the current through a set of defining equations. The explicit solution for the current is obtained in two spacetime dimensions and in the abelian case in three dimensions. The current can be viewed as arising from a non-local, gauge and Lorentz invariant mass term in three dimensions. We also construct a conserved current associated with the symmetry generators and derive some of its properties. In the Abelian case, we compute the symmetry algebra and show that additional symmetry generators have to be included for the algebra to close. The algebra contains an SO(2,1) subalgebra. We comment on the implications of this symmetry for $ \mathcal{N} = 1 $ supersymmetry.
Managerial Performance and Income Variability for a Sample of Illinois Cash Grain Producers

Managerial ability generally is considered a key determinant of success in farming. This analysis evaluates managerial performance over the period 1976–1983 for a sample of 179 Illinois cash grain producers. Characteristics of the superior and inferior performing groups are presented and the variability of performance is assessed.
Buried impact basin distribution on Mars: Contributions from crustal thickness data

[1] Crustal thickness data (derived from Mars Global Surveyor (MGS) gravity field and topographic data) exposes a number of circular thin areas (CTAs) that may represent deeply buried impact basins, which are often not visible in topography alone. A data set which combines quasi-circular depressions (QCDs) revealed by the Mars Orbiter Laser Altimeter (MOLA) on the MGS spacecraft with a population of non-QCD CTAs is a better estimate of the true crater retention ages of the buried surfaces of Mars. This study finds that all regions have older crater retention ages than previously thought based on QCDs alone. The highlands and lowlands appear to have the same basement crater retention age, but Tharsis is younger.
Fayalitic olivine in CV3 chondrite matrix and dark inclusions: A nebular origin

— Fayalitic olivine (Fa32) is the major component of the matrices and dark inclusions of CV3 and other unequilibrated chondrites. It occurs most commonly as rims, veins and halos in and around chondrule silicates in the Allende-type (CV3OXA) chondrites and, to a much lesser extent, in the reduced (CV3R) and Bali-type (CV3OXB) chondrites. The olivines have distinctive platy, tabular and lath- or irregular-shaped crystals, with the ratio of the two types varying widely. In CV3OXB chondrites, matrix fayalitic olivines range up to Fag99.9; whereas, in the other CV3 chondrites, the range is much smaller. The platy and tabular anisotropic forms of the fayalitic olivines strongly suggest growth from a vapor, and the nature of the occurrences suggests that CV3 matrices are unequilibrated mixtures of nebular materials. We argue that the parent body hydration/dehydration model has numerous inconsistencies that make this hypothesis highly unlikely. These include: (1) There is no direct evidence linking fayalitic olivine to precursor phyllosilicates. (2) Dehydration of phyllosilicates cannot explain the wide range of morphologies of the fayalitic olivines. (3) Fayalitic olivine clearly predates the formation of the hydrous phases in CV3 chondrites and is one of the phases that breaks down to form phyllosilicates (Keller et al., 1994). (4) The unequilibrated nature of the matrix, including fine-scale zoning in 10 μm sized fayalitic olivine crystals, would not survive the parent body metamorphism required in the dehydration model. (5) A dark inclusion in the Ningqiang chondrite contains fayalitic olivine rimmed by glassy and microcrystalline material (Zolensky et al., 1997), which probably formed by radiation damage. This indicates that the fayalitic olivine was exposed to solar radiation in a nebular setting. (6) Some Allende chondrules contain unaltered primary, anhydrous glassy mesostasis in contact with the host matrix (e.g., Ikeda and Kimura, 1995). Chondrule mesostases would not have survived parent body hydration without becoming hydrated and would probably not survive the metamorphic heating required in the dehydration scenario. (7) Single platy and barrel-shaped crystals of fayalitic olivine are present in accretionary rims in calcium-aluminum-rich inclusions (CAIs) (MacPherson and Davis, 1997), which developed in the nebula. (8) Matrix lumps completely encased in chondrules in ordinary chondrites contain mainly fayalitic olivine (Scott et al., 1984), which indicates a nebular origin. (9) Oxygen isotopic compositions of Allende matrix and dark inclusions strongly indicate little or no hydration for Allende and its components (Clayton, 1997). We favor a nebular vaporization/recondensation model in which vaporization of chondritic dust produced a fayalite-rich vapor, followed by formation of the fayalitic olivine by direct recondensation from the vapor, epitactic growth on surfaces of existing forsterite and enstatite in chondrules, and replacement of existing forsterite and enstatite by gas-solid exchange.
Low-valent titanium-mediated cyclopropanation of vinylogous esters.

Inter- and intramolecular titanium-mediated cyclopropanation reactions of vinylogous esters are reported. Comparison between the Kulinkovich cyclopropanation of esters and vinylogous esters provides mechanistic insight regarding reaction variables such as reaction temperature, solvents, and a Lewis acid additive.
Mixed-state penetration depths in s-wave and d-wave superconductors

We report on a microscopic calculation of the current and magnetic field distribution in the mixed state of model s-wave and d-wave superconductors. For the d-wave case, we find that corrections to London theory are important at fields small compared to Hc2. The field distribution is influenced by both superfluid-velocity dependence and non-locality in the current response function of the mixed state. We compare our calculations with recent muon spin rotation measurements in high temperature superconductors.
Performance Analysis of Design Process Using Timed Petri Nets

Design in a concurrent engineering environment attempts to minimize the total design time subject to variety of constraints. A limited number of available human resources constrain the simultaneous execution of design activities. In this paper, a timed Petri-net model is built to represent the design process as a discrete event process. The state equations for the timed Petri-net model are established by dioid algebra. When the durations of design activities are deterministic, the allocation of human resources is analyzed by this model by determining the start times of the succeeding activities The discussion on the behavior of the system is further extended to the case when the occurrences of events are probabilistic.
Control of shock-wave/boundary-layer interactions by bleed

This numerical study investigates the effectiveness of bleed in controlling shock-wave/boundary-layer interactions on a flat plate with a focus on understanding how bleed-hole angle, presence of upstream and downstream bleed holes, and pressure ratio across bleed holes affect structure of barrier shock, surface pressure distribution, and bleed rate (in terms of flow coefficient). The bleed-hole angles investigated are 30 deg slanted and 90 deg normal, which give rise to two different types of barrier shocks. The influence of upstream and downstream bleed holes were investigated by studying the bleed process through an isolated hole and through three holes arranged in tandem along the streamwise direction. The plenum/freestream pressure ratios investigated range from 0.3 to 1.7, which produced choked and unchoked flows in the bleed holes. This study is based on the ensemble-averaged, full compressible Navier-Stokes equations closed by the Baldwin-Lomax model with solutions obtained by an implicit finite volume method on an overlapping Chimera grid.
Estimating the Risk of Technology Development

Abstract:A case study is presented on risk management as applied to the development of advanced technologies. The success of complex projects depends on the parallel development and integration of diverse technologies. Prior to investing large sums of money in these technologies, stakeholders want to know the risk in technology investment that includes the probability of technology development success and the impact the technology would have on the system. The risk identification process consists of developing the functional and technology needs of the system; collecting data on potential technology solutions; assessing the technology development probability of success for performance, cost, and schedule; determining the impact of the technology on the programs; and developing decision analysis presentations for the stakeholders. Based on a modified analytical hierarchical process, the Internet-Accessible Technology Risk Assessment Collaborative System (ITRACS©) was developed to solicit opinions from expe...
Electro-Optic Polymer/TiO2 Multilayer Slot Waveguide Modulators for Optical Interconnections

We propose and demonstrate a novel electro-optic (EO) polymer/TiO2 multilayer slot waveguide modulator for optical interconnections.
Cu(I)-catalyzed diamination of conjugated olefins with tunable anionic counterions. A possible approach to asymmetric diamination.

Various achiral and chiral Cu(I) salts have been prepared from mesitylcopper(I) and investigated for the diamination of conjugated olefins with 1,3-di-tert-butyldiaziridinone as nitrogen source. It has been found that copper(I) phosphate has high catalytic activity for the diamination, and encouraging ee’s have also been achieved with chiral phosphates as anionic counterions.
Performance Assessment of Public Sector Scientists

Publicly-funded scientific research establishments are complex organizations requiring considerable management skills to optimize performance. This article identifies the performance indicators (PIs) used in the appraisal of public sector science in the UK and assesses their relevance in relation to the Balanced Score Card (BSC) management tool. The author found that current PIs in UK science relate primarily to scientific peer-group interests and are unlikely, on their own, to facilitate the optimization of organizational management. The article also suggests how concentration on these PIs could hinder the implementation of government science policies, for example public understanding of science, and wealth creation.
Postoperative Delirium: A 76-Year-Old Woman With Delirium Following Surgery

Delirium (acute confusion) complicates 15% to 50% of major operations in older adults and is associated with other major postoperative complications, prolonged length of stay, poor functional recovery, institutionalization, dementia, and death. Importantly, delirium may be predictable and preventable through proactive intervention. Yet clinicians fail to recognize and address postoperative delirium in up to 80% of cases. Using the case of Ms R, a 76-year-old woman who developed delirium first after colectomy with complications and again after routine surgery, the diagnosis, prevention, and treatment of delirium in the postoperative setting is reviewed. The risk of postoperative delirium can be quantified by the sum of predisposing and precipitating factors. Successful strategies for prevention and treatment of delirium include proactive multifactorial intervention targeted to reversible risk factors, limiting use of sedating medications (especially benzodiazepines), effective management of postoperative pain, and, perhaps, judicious use of antipsychotics.
Airfoil wake and linear theory gust response including sub- and superresonant flow conditions

The unsteady aerodynamic gust response of a high solidity stator vane row is examined in terms of the fundamental gust modeling assumptions with particular attention given to the effects near an acoustic resonance. A series of experiments was performed with gusts generated by rotors comprised of perforated plates and airfoils. It is concluded that, for both the perforated plate and airfoil wake generated gusts, the unsteady pressure responses do not agree with the linear-theory gust predictions near an acoustic resonance. The effects of the acoustic resonance phenomena are clearly evident on the airfoil surface unsteady pressure responses. The transition of the measured lift coefficients across the acoustic resonance from the subresonant regime to the superresonant regime occurs in a simple linear fashion.
The Progression of Renal Disease

IN the past two decades, clinical and experimental studies have markedly expanded our understanding of the causes of renal disease. Enhanced understanding of the diverse pathogenetic mechanisms (vascular, metabolic, or immunologic disorders) involving the glomeruli, the interstitium, or both has not, however, resulted in commensurate therapeutic advances. Chronic renal insufficiency, once established, tends to progress to end-stage renal failure. Although there are some exceptions, efforts to halt or even slow the progression of chronic renal disease have been unsuccessful. The mechanisms underlying the progression of renal disease have remained obscure for at least two reasons. First, the glomerulus and the . . .
Intermolecular Effects in the Center-of-Mass Dynamics of Unentangled Polymer Fluids

The generalized Langevin equation for the cooperative dynamics of interacting polymer chains is implemented to investigate the anomalous dynamics of unentangled polymer melts. The proposed equation of motion formally relates the anomalous center-of-mass diffusion, as observed in computer simulations and experiments, to the nature of the effective intermolecular mean-force potential. An analytical Gaussian-core form of the potential between the centers of mass of two polymers is derived, which agrees with computer simulations and allows the analytical solution of the equation of motion. The calculated center-of-mass dynamics is characterized by an initial subdiffusive regime that persists for the spatial range of the intermolecular mean-force potential and for time intervals shorter than the first intramolecular relaxation time, in agreement with experiments and computer simulations of unentangled polymer melt dynamics.
An interdisciplinary research agenda for the study of ecological-economic systems in the American West

Abstract Increased public awareness of resource management issues and new attitudes toward resource conservation have led to great interest in the subject of the apposite use and management of natural and environmental resources in the American West. This paper analyzes this subject from an interdisciplinary ecological-economic perspective. Four salient issues concerning the study of the West's ecological-economic systems that remain inadequately understood are identified and then discussed. A research agenda is proposed to answer some key questions concerning the functioning, health, and management of the West's ecological-economic systems.
Spatial-temporal imaging in the strong-field limit

Abstract form only given. An approach is discussed for producing molecular images with sub-Angstrom atomic precision with few femtosecond exposures. The laser-induced electron diffraction procedure extracts a diffraction pattern from the photoelectron momentum distribution produced by strong-field mid-infrared ionization.
A Strong Test of the von Liebig Hypothesis

DEPARTMENT OF AGRICULTURAL AND RESOURCE ECONOMICS AND POLIJ;Y1 DIVISION OF AGRICULTURE AND NATURAL RESOURCES ~IVERSITY OF CALIFORNIA AT BERKELEY, WORKING PAPER No. 860 A STRONG TEST OF THE V ON LIEBIG HYPOTHESIS by Peter Berek, Jacqueline Geoghegan, and Stephen Stobs California Agricultural Experiment Station Giannini Foundation of Agricultural Economics October 1998
SIGNAL PROCESSING ALGORITHMS FOR STARING SINGLE PIXEL HYPERSPECTRAL SENSORS

Remote sensing of chemical warfare agents (CWA) with stand-off hyperspectral sensors has a wide range of civilian and military applications. These sensors exploit the spectral changes in the ambient photon flux produced thermal emission or absorption after passage through a region containing the CWA cloud. In this work we focus on (a) staring single-pixel sensors that sample their field of view at regular intervals of time to produce a time series of spectra and (b) scanning single or multiple pixel sensors that sample their FOV as they scan. The main objective of signal processing algorithms is to determine if and when a CWA enters the FOV of the sensor. We shall first develop and evaluate algorithms for staring sensors following two different approaches. First, we will assume that no threat information is available and we design an adaptive anomaly detection algorithm to detect a statistically-significant change in the observed spectrum. The algorithm processes the observed spectra sequentially-in-time, estimates adaptively the background, and checks whether the next spectrum differs significantly from the background based on the Mahalanobis distance or the distance from the background subspace. In the second approach, we will assume that we know the spectral signature of the CWA and develop sequential-in-time adaptive matched filter detectors. In both cases, we assume that the sensor starts its operation before the release of the CWA; otherwise, staring at a nearby CWA-free area is required for background estimation. Experimental evaluation and comparison of the proposed algorithms is accomplished using data from a long-wave infrared (LWIR) Fourier transform spectrometer.
Puzzle geometry and rigidity: The Fibonacci cycle is hyperbolic

We describe a new and robust method to prove rigidity results in complex dynamics. The new ingredient is the geometry of the critical puzzle pieces: under control of geometry and ``complex bounds'', two generalized polynomial-like maps which admit a topological conjugacy, quasiconformal outside the filled-in Julia set, are indeed quasiconformally conjugate. The proof uses a new abstract removability-type result for quasiconformal maps, following ideas of Heinonen and Koskela and of Kallunki and Koskela, optimized for applications in complex dynamics. We prove, as the first application of this new method, that, for even criticalities distinct from two, the period two cycle of the Fibonacci renormalization operator is hyperbolic with -dimensional unstable manifold.
The Weak-Field Limit of the Magnetorotational Instability

We investigate the behavior of the magnetorotational instability in the limit of extremely weak magnetic field, i.e., as the ratio of ion cyclotron frequency to orbital frequency (X) becomes small. Considered only in terms of cold two-fluid theory, instability persists to arbitrarily small values of X, and the maximum growth rate is of the order of the orbital frequency except for the range me/mi 0) produces slower growth than antialigned field (X < 0). The maximum growth rate is generally achieved at smaller and smaller wavelengths as |X| diminishes. When |X| < me/mi, new unstable "electromagnetic-rotational" modes appear that do not depend on the equilibrium magnetic field. Because the most rapidly growing modes have extremely short wavelengths when |X| is small, they are often subject to viscous or resistive damping, which can result in suppressing all but the longest wavelengths, for which growth is much slower. We find that this sort of damping is likely to severely curtail the frequently invoked mechanism for cosmological magnetic field growth in which a magnetic field seeded by the Biermann battery is then amplified by the magnetorotational instability. On the other hand, the small-|X| case may introduce interesting effects in weakly ionized disks in which dust grains carry most of the electric charge.
Allylic C−H Acetoxylation with a 4,5-Diazafluorenone-Ligated Palladium Catalyst: A Ligand-Based Strategy To Achieve Aerobic Catalytic Turnover

Pd-catalyzed C−H oxidation reactions often require the use of oxidants other than O2. Here we demonstrate a ligand-based strategy to replace benzoquinone with O2 as the stoichiometric oxidant in Pd-catalyzed allylic C−H acetoxylation. Use of 4,5-diazafluorenone (1) as an ancillary ligand for Pd(OAc)2 enables terminal alkenes to be converted to linear allylic acetoxylation products in good yields and selectivity under 1 atm O2. Mechanistic studies have revealed that 1 facilitates C−O reductive elimination from a π-allyl−PdII intermediate, thereby eliminating the requirement for benzoquinone in this key catalytic step.
Transport phenomena in heterogeneous media based on volume averaging theory

Models are developed to describe transport phenomena in a porous medium that take into account the scales and other characteristics of the medium morphology. Equation sets allowing for turbulence and two-temperature or two-concentration diffusion are obtained for non-isotropic porous media with interface exchange. The equations differ from known equations and were developed using an advanced averaging technique, hierarchical modeling methodology, and fully turbulent models with Reynolds stresses and fluxes in the space of every pore. The transport equations are shown to have additional integral and differential terms. The description of the structural morphology determines the importance of these terms and the range of application of the closure schemes. A natural way to transfer from transport equations in a porous media with integral terms to differential equations with coefficients that could be experimentally evaluated and determined is described.Some numerical results that illustrate what occurs when the porosity approaches unity or the porosity approaches zero show that solutions smoothly converge to the transport characteristics of a plane channel. A simple heat sink is modeled as a two-temperature process allowing solution of the conjugate problem to be accomplished and is optimized using design of experiment (DOE) methods. As a final example, acoustic energy absorption in a porous media is addressed.
Numerical Ricci-flat metrics on K3

We develop numerical algorithms for solving the Einstein equation on Calabi?Yau manifolds at arbitrary values of their complex structure and K?hler parameters. We show that K?hler geometry can be exploited for significant gains in computational efficiency. As a proof of principle, we apply our methods to a one-parameter family of K3 surfaces constructed as blow-ups of the T4/Z2 orbifold with many discrete symmetries. High-resolution metrics may be obtained on a time scale of days using a desktop computer. We compute various geometric and spectral quantities from our numerical metrics. Using similar resources, we expect our methods to practically extend to Calabi?Yau three-folds with a high degree of discrete symmetry, although we expect the general three-fold to remain a challenge due to memory requirements.
Penetration landing guidance trajectories in the presence of windshear

Flight trajectory guidance in the presence of windshear is considered with reference to flight in a vertical plane. Both horizontal shear and the presence of a downdraft are assumed. The optimal trajectory is first determined by minimizing a performance index which is subject to touchdown constraints, under the assumption of control via angle of attack and power setting. It is shown that the coupling relation between the angle of attack and the power setting can be ignored. A guidance scheme is constructed in which the angle of attack is determined by the windshear intensity, the absolute path inclination, and the glide slope angle, while the power setting is determined by the windshear intensity and the velocity. Particular attention is given to low-altitude penetration landing.
Optimal Control of a Rigid Body using Geometrically Exact Computations on SE(3)

Optimal control problems are formulated and efficient computational procedures are proposed for combined orbital and rotational maneuvers of a rigid body in three dimensions. The rigid body is assumed to act under the influence of forces and moments that arise from a potential and from control forces and moments. The key features of this paper are its use of computational procedures that are guaranteed to preserve the geometry of the optimal solutions. The theoretical basis for the computational procedures is summarized, and examples of optimal spacecraft maneuvers are presented.
Excitons and Plasmons in Superconductors

The Anderson-Rickayzen equations of motion for a superconductor derived within the random-phase approximation (RPA) are used to investigate the collective excitations of superconductors. A spherical harmonic expansion is made of the two-body interaction potential $V(\mathrm{k}, {\mathrm{k}}^{\ensuremath{'}})$ and a spectrum of excitations whose energies lie within the energy gap $2\ensuremath{\Delta}$ is obtained. These excitations may be characterized by the quantum numbers $L$ and $M$ involved in the potential expansion. For an $L$-state exciton to exist, the $L$-wave part of the potential must be attractive at the Fermi surface. Odd-$L$ excitons have unit spin and may be considered as spin waves. For $s$-state pairing in the superconducting ground state, the plasmon mode corresponds to the $L=0$ exciton whose energy is strongly modified by the long-range Coulomb interaction. For a general potential several bound states may exist for given $L$ and $M$. If the $L$-wave potential is stronger than the $s$-wave part of the potential, the system is unstable with respect to formation of $L$-state excitons. In this case, the ground state is formed with $L$-state pairing, special cases of which are the $p$-state pairing considered by Fisher and the $d$-state pairing proposed recently by several authors for the ground state of ${\mathrm{He}}^{3}$ and nuclear matter. Corrections to the Anderson-Rickayzen equations are discussed which lead to a new set of exciton states if the $L$-wave potential is repulsive. These excitons are interpreted as bound electron-hole pairs, as opposed to the particle-particle excitons present with an attractive $L$-wave potential.
Fabrication of high-performance MSM photodetectors on SOI with nanometer-scale scattering buried backside reflectors

We present the fabrication and performance of a metal- semiconductor -metal (MSM) photodetector with high efficiency and high speed. The MSM photodetector is fabricated on a SOI substrate with a 170-nm-thick Si active layer. A scattering backside reflector, consisting of inverted pyramids with 193- nm-long sides and 54.7 degree slopes, is buried underneath the active layer. This scattering buried backside reflector (SBBR) causes the trapping of light inside the active layer, resulting in an MSM photodetector with a response time of 5.4 ps and responsivity comparable with those on bulk Si at both the visible and infrared.
Cluster algebras II: Finite type classification

This paper continues the study of cluster algebras initiated in math.RT/0104151. Its main result is the complete classification of the cluster algebras of finite type, i.e., those with finitely many clusters. This classification turns out to be identical to the Cartan-Killing classification of semisimple Lie algebras and finite root systems, which is intriguing since in most cases, the symmetry exhibited by the Cartan-Killing type of a cluster algebra is not at all apparent from its geometric origin. The combinatorial structure behind a cluster algebra of finite type is captured by its cluster complex. We identify this complex as the normal fan of a generalized associahedron introduced and studied in hep-th/0111053 and math.CO/0202004. Another essential combinatorial ingredient of our arguments is a new characterization of the Dynkin diagrams.
A stochastic approach to estimating earliest start times of nodes for scheduling DAGs on heterogeneous distributed computing systems

Previously, DAG scheduling schemes used the mean (average) of computation or communication time in dealing with temporal heterogeneity. However, it is not optimal to consider only the means of computation and communication times in DAG scheduling on a temporally (and spatially) heterogeneous distributed computing system. In this paper, it is proposed that the second order moments of computation and communication times, such as the standard deviations, be taken into account in addition to their means, in scheduling “stochastic” DAGs. An effective scheduling approach which accurately estimates the earliest start time of each node and derives a schedule leading to a shorter average parallel execution time has been developed. Through an extensive computer simulation, it has been shown that a significant improvement (reduction) in the average parallel execution times of stochastic DAGs can be achieved by the proposed approach.
Changes in blood viscosity and plasma proteins in carcinoma.

Blood viscosity and plasma protein concentrations were measured in 31 patients with a variety of visceral carcinomas. The mean whole blood viscosity was not elevated over normal controls because of a significantly lowered mean hematocrit. However, when hematocrit was eliminated as a variable by adjusting the hematocrit to 45%, the mean whole blood viscosity was significantly elevated in the group with carcinoma. Both the plasma viscosity and the tendency for red cell aggregation were significantly elevated in the group with carcinoma. The fibrinogen and globulin fractions were also significantly elevated Since blood is a non-Newtonian fluid, and its viscosity increases markedly at low shear rates, these rheological abnormalities would be most important at the low shear rates characteristic of the venous circulation. It is suggested that these abnormalities in blood viscosity and red cell aggregation may be contributing to the high incidence of venous thromboembolism seen in patients with neoplastic disease.
Multiresolutional visualization of evolving distributed simulations using wavelets and MPI

This paper presents a technique to losslessly compress and progressively transmit floating point data using wavelets. MPI is employed in the implementation of this technique so that the parallelized solver which runs on a remote computer and the visualization tool which runs on a local graphics workstation can be combined.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Proof of the Boltzmann-Sinai ergodic hypothesis for typical hard disk systems

We consider the system of N (≥2) hard disks of masses m 1,...,m N and radius r in the flat unit torus 𝕋2. We prove the ergodicity (actually, the B-mixing property) of such systems for almost every selection (m 1,...,m N ;r) of the outer geometric parameters.
Gold Catalyzed Intermolecular Markovnikov Hydroamination of Allenes with Secondary Amines

A cationic (CAAC)gold(I) complex promotes the addition of all types of nontertiary amines to a variety of allenes, affording allylic amines in good to excellent yields; the amino fragment always adds to the less substituted terminus of the CCC skeleton.
Languages for expert system building: a comparison

A study of some languages which may be used for expert system building is conducted. The characteristics necessary in an expert system building language are detailed. Languages that are unable to provide for many different types of expert systems to be built are not given much weight. Six relatively standard high level languages are studied, which include FORTRAN, Modula-2, Ada**, Pascal, LISP and Prolog. Some of the newly developed expert system building languages are also studied. The study was done in conjunction with the development of the expert system known as Fess and a discussion of the reasons for the choice of its development language are given. The construction of the system has provided further insights for the language study. It is found that a best expert system building language may yet be developed.** Ada is a trademark of the DoD (Ada Joint Program Office)
Utilization of Control Effort Constraints in Linear Controller Design

Constraints on control effort, although important in control system performance, are difficult to incorporate into standard procedures for controller design. A design procedure which accounts for such constraints is developed by requiring that the control system utilize the maximum energy delivering capability of the final control elements under some specified test conditions (e.g., maximum step reference input). Results using this approach are available for low-order single-input single-output controlled systems from previous studies. This paper presents additional results for certain classes of multi-input multi-output systems where the number of inputs is equal to the number of states. Both state variable feedback control for regulation, and integral plus state variable feedback control for tracking are considered and illustrated with an example problem.
Chiral symmetry restoration in the instanton liquid at finite density

Abstract The properties of the QCD partition function at finite chemical potential are studied within the instanton liquid model. It is shown that the density dependence of the quark-induced instanton-antiinstanton (I-A) interaction leads to the formation of topologically neutral I-A pairs (‘molecules’), resulting in a first order chiral phase transition at a critical chemical potential μ c q ⋍ 310 MeV . At somewhat higher densities (μq ≥ 360 MeV), the quark Fermi surface becomes instable with respect to diquark condensation (Cooper pairs) generating BCS-type energy gaps of order 50 MeV.
Kink Collisions in Curved Field Space

We study bubble universe collisions in the ultrarelativistic limit with the new feature of allowing for nontrivial curvature ineld space. We establish a simple geometrical interpretation of such collisions in terms of a double family ofeld proles whose tangent vectorelds stand in mutual parallel transport. This provides a generalization of the well- known ateld space limit of the free passage approximation. We investigate the limits of this approximation and illustrate our analytical results with numerical simulations.
A Separation Principle for Gyroscopic Conservative Systems

Closed-form solutions to differential eigenvalue problems associated with natural conservative systems, albeit self-adjoint, can be obtained in only a limited number of cases. Approximate solutions generally require spatial discretization, which amounts to approximating the differential eigenvalue problem by an algebraic eigenvalue problem. If the discretization process is carried out by the Rayleigh-Ritz method in conjunction with the variational approach, then the approximate eigenvalues can be characterized by means of the Courant and Fischer maximin theorem and the separation theorem. The latter theorem can be used to demonstrate the convergence of the approximate eigenvalues thus derived to the actual eigenvalues. This paper develops a maximin theorem and a separation theorem for discretized gyroscopic conservative systems, and provides a numerical illustration.
Applying the cluster method to count occurrences of generalized permutation patterns

We apply ideas from the cluster method to q-count the permutations of a multiset according to the number of occurrences of certain generalized patterns, as defined by Babson and Steingrimsson. In particular, we consider those patterns with three letters and one internal dash, as well as permutation statistics composed of counting the number of occurrences of multisets of such patterns. Counting is done via recurrences which simplify in the case of permutations. A collection of Maple procedures implementing these recurrences accompanies the article.
An Experimental Evaluation of the Stresses in Drilled Balls

Stresses in dimensionally similar large models of 40-, 50- and 60-percent mass reduction cylindrically hollow 'drilled' bearing balls were experimentally evaluated with flat strain gage rosettes. Dimensionless principal stress coefficients were calculated and were applied to estimate the bending stresses in the drilled balls of three series of full-scale bearing experiments. Stresses were highest when the applied load approached the edge of the hole, and ranged up to almost 620 million Newtons per sq m at the bore.
Neutralino-sbottom coannihilation in SU(5)

We identify within the SU(5) framework the minimum number of soft supersymmetry breaking parameters which can yield a bottom squark (sbottom) as the next to lightest supersymmetric particle. We focus in particular on the neutralino-sbottom coannihilation scenario which gives rise to the desired neutralino dark matter relic density. We find solutions in which the sbottom mass is greater than or of order 210 GeV, while the gluino and the first two family squarks are heavier than 1 TeV. Some benchmark points which can be tested at the LHC are presented.
Synthesis, characterization and catalytic properties of manganese(III) schiff base complexes

Abstract The syntheses and spectral and electrochemical characterization of five manganese(III) complexes with Schiff base ligands are described. The crystal structure of the complex [Mn(SALENCY)(H2O)(CH3CH2OH)]ClO4 where SALENCY, C20H20N2O22-−, is the dianion of the product formed from the condensation of two moles of salicylaldehyde with one mole of 1,2-diaminocyclohexane, has been established by X-ray diffraction techniques. The complex crystallizes in the space group P21/n of the monoclinic system with four molecules in a cell of dimensions a=11.678(3), b=15.654(3), c= 13.356(2) A, and β=93.00(2)°. The structure was solved by direct methods and refined by least-squares techniques to a final value of the weighted R factor of 0.0437 based on 1484 independent observed reflections. The complex is roughly octahedral, the Schiff base ligand occupying four basal sites while the axial sites are occupied by one water molecule and one ethanol molecule. The complex [Mn(TETRAMESALEN)Cl], where TETRAMESALEN, C20H22N2O22−, is the dianion of the product formed from the condensation of two moles of 2′-hydroxy- 5′-methylacetophenone with one mole of 1,2- diaminoethane, crystallizes in the monoclinic space group P21/c with four molecules in a cell of dimensions a=11.009(4), b=12.459(3), c=13.967(4) A, β=97.25(3)°. The structure was solved by direct methods and refined to a final R factor of 0.0535 based on 2342 observed independent intensities. The complex is tetragonal pyramidal, the Schiff base ligand occupying the basal sites while the chloride is axial. The complex [Mn(MEPHSALEN)(C2H5OH)2]- ClO4, where MEPHSALEN, C30H26N2O22-−, is the dianion of the product formed from the condensation of two moles of 2′-hydroxy- 5′-methylbenzophenone with one mole of 1,2-diaminoethane, crystallizes in the triclinic space group P 1 with four molecules in a cell of dimensions a=9.492(3), b=17.404(6), c= 21.265(9) A, α=86.60(3), β=88.57(3), γ= 86.34(3)°. The data for this complex are of lower quality than those obtained for the other two complexes, but the structure has been refined to a final value of 0.090 based on 1263 independent intensities. There are two crystallographically independent molecules in the cell, but the geometry of each is substantially similar. In each case, the manganese atom is six-coordinate, the base of the pseudo-octahedron being occupied by the Schiff base ligand while the axial sites are occupied by ethanol ligands. The two six-coordinate complexes (SALENCY and MEPHSALEN) are very effective at catalyzing the epoxidation of cyclohexene by iodosobenzene, while the five-coordinate complex yields both epoxide and cyclohexenol.
Hepatic Cysts in Autosomal Dominant Polycystic Kidney Disease

Hepatic cysts are one of several extrarenal manifestations of the ADPKD gene. Several factors, including age, gender, pregnancy, the degree of renal cystic disease, and the extent of renal functional impairment, may modify the expression of hepatic cystic disease. With advances in medical care, such as improvement in the management of end-stage renal disease, hemodialysis, and renal transplantation, patients with ADPKD will experience an increased life expectancy. As a result, complications associated with hepatic cysts may become more common, and physicians may encounter an increasing number of patients with ADPKD who have infected hepatic cysts. Several issues in the management of this complication remain unresolved, but the article by Telenti and associates in this issue of the Proceedings addresses some of the critical issues that physicians who are responsible for the care of these patients will certainly confront in future years.
On the Loss of Continuity for Super-Critical Drift-Diffusion Equations

We show that there exist solutions of drift-diffusion equations in two dimensions with divergence-free super-critical drifts that become discontinuous in finite time. We consider classical as well as fractional diffusion. However, in the case of classical diffusion and time-independent drifts, we prove that solutions satisfy a modulus of continuity depending only on the local L 1 norm of the drift, which is a super-critical quantity.
On-line extraction of SCSI disk drive parameters

Sophisticated disk scheduling algorithms require accurate, detailed disk drive specifications, including data about mechanical delays, on-board caching and prefetching algorithms, command and protocol overheads, and logical-to-physical block mappings. Comprehensive disk models used in storage subsystem design require similar levels of detail. We describe a suite of general-purpose algorithms and techniques for acquiring the necessary information from a SCSI disk drive. Using only the ANSI-standard interface, we demonstrate how the important parameter values of a modern SCSI drive can be determined accurately and efficiently.
Contingent planning under uncertainty via stochastic satisfiability

We describe a new planning technique that efficiently solves probabilistic propositional contingent planning problems by converting them into instances of stochastic satisfiability (SSAT) and solving these problems instead. We make fundamental contributions in two areas: the solution of SSAT problems and the solution of stochastic planning problems. This is the first work extending the planning-as-satisfiability paradigm to stochastic domains. Our planner, ZANDER, can solve arbitrary, goal-oriented, finite-horizon partially observable Markov decision processes (POMDPS). An empirical study comparing ZANDER to seven other leading planners shows that its performance is competitive on a range of problems.
Statistical Significance of Clustering Using Soft Thresholding

Clustering methods have led to a number of important discoveries in bioinformatics and beyond. A major challenge in their use is determining which clusters represent important underlying structure, as opposed to spurious sampling artifacts. This challenge is especially serious, and very few methods are available, when the data are very high in dimension. Statistical significance of clustering (SigClust) is a recently developed cluster evaluation tool for high-dimensional low sample size (HDLSS) data. An important component of the SigClust approach is the very definition of a single cluster as a subset of data sampled from a multivariate Gaussian distribution. The implementation of SigClust requires the estimation of the eigenvalues of the covariance matrix for the null multivariate Gaussian distribution. We show that the original eigenvalue estimation can lead to a test that suffers from severe inflation of Type I error, in the important case where there are a few very large eigenvalues. This article addr...
Optimal serial distributed decision fusion

The problem of distributed detection involving N sensors is considered. The configuration of sensors is serial in the sense that the Jth sensor decides using the decision it receives along with its own observation. When each sensor uses the Neyman-Pearson test, the probability of detection is maximized for a given probability of false alarm, at the Nth stage. With two sensors, the serial scheme has a performance better than or equal to the parallel fusion scheme analyzed in the literature. Numerical examples illustrate the global optimization by the selection of operating thresholds at the sensors. >