cssi/SciSciGPT-SciSciNet huggingface dataset:
Randomness-efficient sampling within NC 1

We construct a randomness-efficient averaging sampler that is computable by uniform constant-depth circuits with parity gates (i.e., in uniform AC0[⊕]). Our sampler matches the parameters achieved by random walks on constant-degree expander graphs, allowing us to apply a variety expander-based techniques within NC1. For example, we obtain the following results: Randomness-efficient error-reduction for uniform probabilistic NC1, TC0, AC0[⊕] and AC0: Any function computable by uniform probabilistic circuits with error 1/3 using r random bits is computable by uniform probabilistic circuits with error δ using r + O(log(1/δ)) random bits. Optimal explicit e-biased generator in AC0[⊕]: There is a 1/2Ω( n)-biased generator $G:{0, 1}^{O(n)} \to {0, 1}^{2^n}$ for which poly(n)-size uniform AC0[⊕] circuits can compute G(s)i given (s, i) ∈0, 1O( n) ×0, 1n. This resolves a question raised by Gutfreund & Viola (Random 2004). uniform BP ·AC0⊆ uniform AC0/O(n). Our sampler is based on the zig-zag graph product of Reingold, Vadhan and Wigderson (Annals of Math 2002) and as part of our analysis we give an elementary proof of a generalization of Gillman's Chernoff Bound for Expander Walks (FOCS 1994).
Welfare effects of improving end-use efficiency: Theory and application to residential electricity demand

Abstract This paper applies the money metric approximation to the Hicksian equivalent variation and the generalized logit model of consumer demand to the analysis of the welfare effects of end-use efficiency improvements in various electricity conservation options. The results are compared with the standard cost-effectiveness criterion based on the net present value of energy conservation investments. If the assumptions implicit in the use of this criterion hold, namely, zero end-use price and income elasticities, the net present value of an investment will be the same as the money equivalent of the net welfare change calculated by the money metric. However, the standard net present value becomes less accurate as a measure of welfare change as the end-use price and income elasticities differ significantly from zero. The money metric welfare change measure is theoretically more accurate. It is also more general since it encompasses cases where the above assumptions of the net present value criterion do not hold, i.e, net present value is a special case of the money metric.
Dendrimer-encapsulated metal nanoparticles and their applications to catalysis

Abstract This account describes the synthesis, characterization, and applications to catalysis of dendrimer-encapsulated metal nanoparticles (DEMNs). These materials are synthesized by a template approach in which metal ions are sorbed into the interior of dendrimers and then subsequently chemically reduced to yield nearly size-monodisperse, zero-valent metal particles having dimensions of less than 4 nm. The dendrimer component of these composites serve not only as a template for preparing the nanoparticle replica, but they also stabilize the nanoparticle, make it possible to tune solubility, and enhance catalytic selectivity. These materials have been used for a broad range of catalytic reactions, including hydrogenations, Heck coupling, and Suzuki reactions, in water, organic solvents, biphasic fluorous/organic solvents, and supercritical CO 2 . In many cases it is very simple to recycle the dendrimer-encapsulated catalysts. In addition to monometallic DEMNs, bimetallic materials have also recently been prepared and their catalytic properties are reported. To cite this article: Y. Niu et al., C. R. Chimie 6 (2003).
On-line learning neural-network controllers for autopilot systems

This paper proposes the implementation of on-line learning neural controllers in the autopilot control laws of a modern high-performance aircraft. A first advantage of this design philosophy consists in avoiding the precomputation, storing, and interpolation between thousands of feedback gains of a typical flight control system. Another advantage is the ability to compensate for nonlinearities and model uncertainties. In addition, an on-line learning time-varying neural architecture will avoid the time-consuming gain recalculation following any modification to the aircraft or to its control system during its operative life. The implementation of these types of alternative controllers is made possible by the recent simultaneous advances in neural-network technology with regard to the availability of efficient and fast learning algorithms, along with progress in digital microprocessors. The approach is shown using a six-degree-of-freedom nonlinear simulation code. The traditional gain-scheduling-based control laws for typical autopilot functions are replaced by on-line learning neural architectures trained with the extended back-propagation algorithm. This algorithm has shown substantial improvements over the conventional back-propagation method in learning speed and accuracy. The results of the simulation with and without a man in the loop are presented and discussed.
On the hodge metric of the universal deformation space of Calabi-Yau threefolds

In this paper, we represent the Hodge metric in terms of the Weil-Petersson metric and its Ricci curvature on the moduli spaces of polarized Calabi-Yau threefolds.
Alternative Income Determination Rules and Earnings Usefulness: The Case of R&D Costs*

Abstract. Accounting procedures have been suggested as a factor affecting the usefulness of reported earnings for the users of financial statements. However, little evidence exists to confirm the ways in which mandatory changes in income determination rules influence the way the market responds to accounting information. This study expands the existing literature by testing the notion that accounting method choice can affect earnings usefulness for firms engaged in research and development (RD and (2) differences in earnings usefulness between similar firms using different R&D accounting methods prior to the rule change. We find that for our sample of R&D firms, there is a statistically significant decline in earnings usefulness for firms forced to switch from capitalizing to expensing R&D outlays, and that the decline appears to persist over time. In addition, the comparison of earnings usefulness between firms using different R&D accounting methods before SFAS No. 2 indicates that capitalizing firms had significantly higher earnings usefulness than expensing firms. Resume. L'on a dit des methodes comptables qu'elles avaient une incidence sur l'utilite des benefices declares pour les utilisateurs des etats financiers. Peu de travaux etablissent cependant de quelles facons les modifications obligatoires des regles regissant le calcul des benefices influent sur la reaction du marche a l'information comptable. Les auteurs enrichissent la documentation existante en testant la notion voulant que le choix de la methode comptable puisse influer sur l'utilite des benefices dans le cas des entreprises qui poursuivent des activites de recherche et developpement (R&D). Ils testent des hypotheses qui ont trat 1) a la variation de l'utilite de l'information relative aux benefices dans le cas d'entreprises ayant change de methode de comptabilisation des frais de R&D par suite de la publication du SFAS no 2 et 2) aux differences dans l'utilite de l'information relative aux benefices entre entreprises similaires recourant a des methodes de comptabilisation des frais de R&D qui sont differentes, avant la modification des regles. Dans leur echantillon d'entreprises qui se consacrent a des activites de R&D, les auteurs observent un declin statistiquement significatif dans l'utilite de l'information relative aux benefices chez les entreprises obligees de passer de la capitalisation a la passation en charges des frais de R&D et notent que ce declin semble persister dans le temps. En outre, la comparaison des donnees observees chez des entreprises appliquant differentes methodes de comptabilisation des frais de R&D avant la publication du SFAS no 2 revele que l'utilite de l'information relative aux benefices des entreprises qui capitalisent leurs frais de R&D est beaucoup plus grande que celle de l'information relative aux benefices des entreprises qui imputent ces frais a l'exercice.
A Correlation between Pre-Main-Sequence Stellar Rotation Rates and IRAC Excesses in Orion

Early observations of T Tauri stars suggested that stars with evidence of circumstellar accretion disks rotated slower than stars without such evidence, but more recent results are not as clear. Near-IR circumstellar disk indicators, although the most widely available, are subject to uncertainties that can result from inner disk holes and/or the system inclination. Mid-infrared observations are less sensitive to such effects, but until now, these observations have been difficult to obtain. The Spitzer Space Telescope now easily enables mid-infrared measurements of large samples of PMS stars covering a broad mass range in nearby star-forming regions. Megeath and collaborators surveyed the Orion Molecular Clouds (~1 Myr) with the IRAC instrument (3.6, 4.5, 5.8, 8μm) as part of a joint IRAC and MIPS GTO program. We examine the relationship between rotation and Spitzer mid-IR fluxes for ~900 stars in Orion for stars between 3 and 0.1 M(.). We find in these Spitzer data the clearest indication to date that stars with longer periods are more likely than those with short periods to have IR excesses suggestive of disks.
QUANTUM SINGULARITIES IN STATIC AND CONFORMALLY STATIC SPACE-TIMES

The definition of quantum singularity is extended from static space-times to conformally static space-times. After the usual definitions of classical and quantum singularities are reviewed, examples of quantum singularities in static space-times are given. These include asymptotically power-law space-times, space-times with diverging higher-order differential invariants, and a space-time with a 2-sphere singularity. The theory behind quantum singularities in conformally static space-times is followed by an example, a Friedmann-Robertson-Walker space-time with cosmic string. The paper concludes by discussing areas of future research.
N = 2 supersymmetric gauge theories, branes and orientifolds

Abstract Starting with configurations of fourbranes, fivebranes, sixbranes and orientifolds in type 11A string theory we derive via M-theory the curves solving N = 2 supersymmetric gauge theories with gauge groups SO ( N ) and Sp (2 N ). We also obtain new curves describing theories with product gauge groups. A crucial role in the discussion is played by the interaction of the orientifolds with the NS-fivebranes.
Hierarchical clustering with topology databases

Abstract Dynamic routing in networks helps to provide efficient utilization of network resources. However, when networks are too large, the overhead introduced by dynamic routing consumes too much of network resources (processing, transmission capacity, and storage). To overcome this, researchers have investigated techniques to hierarchically organize networks and thereby reduce overhead. This paper introduces a new technique to organize routing information in large networks. A “radius database” provides optimal routing between frequent communicators. The combination of a “cluster database”, and a backbone, allows reasonable routing to all nodes. The paper details the information maintained at each node, describes distributed update algorithms to allow dynamic maintenance of the information, and indicates how to cluster networks to take advantage of this techniques. Simulation results support the efficacy of the technique.
On Angular Momentum Transport in Convection-dominated Accretion Flows

Convection-dominated accretion flow (CDAF) is a promising model to explain underluminous accreting black holes in X-ray binaries and galactic nuclei. I discuss the effects of angular momentum transport in viscous hydrodynamical and MHD CDAFs. In hydrodynamical CDAFs, convection transports angular momentum inward, and this, together with the outward convection transport of thermal energy, determine the radial structure of the flow. In MHD CDAFs, convection can transport angular momentum either inward or outward, depending on the properties of turbulence in rotating magnetized plasma, which are not fully understood yet. The direction of convection angular momentum transport can affect the law of rotation of MHD CDAFs.
Piezoresistive geometry for maximizing microcantilever array sensitivity

Our group has focused on the development of piezoresistive cantilevers for gas detection using a nonreaction-based method - viscous damping. This work represents a continuation of this effort by reporting on the development, fabrication and testing of a second generation device consisting of asymmetric piezoresistive cantilevers to maximize device sensitivity. The first mode of resonance, static & dynamic sensitivities, and Q-factors ranged from 40 kHz - 63 kHz, 1-6 Omega/mum & 3-17 Omega/mum, and 1700 - 4200, respectively, depending on piezoresistor geometry and beam length. The redesigned piezoresistive microcantilevers were 15 - 200 times more sensitive than the best symmetric design previously reported by our group.
Aircraft Turbine Engine Control Research at NASA Glenn Research Center

This paper provides an overview of the aircraft turbine engine control research at the NASA Glenn Research Center (GRC). A brief introduction to the engine control problem is first provided with a description of the state-of-the-art control law structure. A historical aspect of engine control development since the 1940s is then provided with a special emphasis on the contributions of GRC. With the increased emphasis on aircraft safety, enhanced performance, and affordability, as well as the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at GRC is leading and participating in various projects to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA Aeronautics Research Mission programs. The rest of the paper provides an overview of the various CDB technology development activities in aircraft engine control and diagnostics, both current and some accomplished in the recent past. The motivation for each of the research efforts, the research approach, technical challenges, and the key progress to date are summarized.
Edge Currents and Vertex Operators for Chern-Simons Gravity

We apply elementary canonical methods for the quantization of 2+1 dimensional gravity, where the dynamics is given by E. Witten’s ISO(2, 1) Chern-Simons action. As in a previous work, our approach does not involve choice of gauge or clever manipulations of functional integrals. Instead, we just require the Gauss law constraint for gravity to be first class and also to be everywhere differentiable. When the spatial slice is a disc, the gravitational fields can either be unconstrained or constrained at the boundary of the disc. The unconstrained fields correspond to edge currents which carry a representation of the ISO(2, 1) Kac-Moody algebra. Unitary representations for such an algebra have been found using the method of induced representations. In the case of constrained fields, we can classify all possible boundary conditions. For several different boundary conditions, the field content of the theory reduces precisely to that of 1+1 dimensional gravity theories. We extend the above formalism to include sources. The sources take into account self-interactions. This is done by punching holes in the disc, and erecting an ISO(2, 1) Kac–Moody algebra on the boundary of each hole. If the hole is originally sourceless, a source can be created via the action of a vertex operator V. We give an explicit expression for V. We shall show that when acting on the vacuum state, it creates particles with a discrete mass spectrum. The lowest mass particle induces a cylindrical space-time geometry, while higher mass particles give an n fold covering of the cylinder. The vertex operator therefore creates cylindrical space-time geometries from the vacuum.
Tentative Detection of Quasar Feedback from WMAP and SDSS Cross-correlation

We perform a cross-correlation analysis of microwave data from Wilkinson Microwave Anisotropy Probe and photometric quasars from the Sloan Digital Sky Survey, testing for Sunyaev-Zeldovich (SZ) effect from quasars. A statistically significant (2.5 σ) temperature decrement exists in the 41 GHz microwave band. A two-component fit to the cross-correlation spectrum incorp orating both dust emission and SZ yields a best-fit y parameter of (7.0± 3.4)× 10 −7 . A similar cross-correlation analysis with the Luminous Red Galaxy sample from Sloan gives a best-fit y parameter of (5.3± 2.5)× 10 −7 . We discuss the possible physical origin of these signals, which is likely a combination of SZ effects from quasars and from galaxy clusters. Both the Planck Surveyor satellite and current ground-based arcminute-re solution microwave experiments will detect this signal with a higher statistical significance. Subject headings:Cosmology:cosmic microwave background-galaxies:active-submillimeter: general
Synthesizing optimal waste blends

Vitrification of tank wastes to form glass is a technique that will be used for the disposal of high-level waste at Hanford. Process and storage economics show that minimizing the total number of glass logs produced is the key to keeping cost as low as possible. The amount of glass produced can be reduced by blending of the wastes. The optimal way to combine the tanks to minimize the volume of glass can be determined from a discrete blend calculation. However, this problem results in a combinatorial explosion as the number of tanks increases. Moreover, the property constraints make this problem highly nonconvex where many algorithms get trapped in local minima. In this paper we examine the use of different combinatorial optimization approaches to solve this problem. A two-stage approach using a combination of simulated annealing and nonlinear programming (NLP) is developed. The results of different methods such as the heuristics approach based on human knowledge and judgment, the mixed integer nonlinear programming (MINLP) approach with GAMS, and branch and bound with lower bound derived from the structure of the given blending problem are compared with this coupled simulated annealing and NLP approach.
Unfoldable cardinals and the GCH

Unfoldable cardinals are preserved by fast function forcing and the Laver-like preparations that fast functions support. These iterations show, by set-forcing over any model of ZFC, that any given unfoldable cardinal κ can be made indestructible by the forcing to add any number of Cohen subsets to κ.
Convolutional codes from group rings

Convolutional codes have been widely used and studied. Many of the best current convolutional codes have been found through computer search. However, constructing these codes by algebraic means will allow bigger codes to be found while maintaining high speed and low memory. Units in the group ring have been used to construct convolutional codes. These have been used to construct several known codes and several new codes. These known constructions are extended to a new construction. This new construction allows for calculations of lower bounds of the free distances produced by some types of generators. It is shown that all (2, 1) systematic convolutional codes may be constructed using group rings with the new construction. The new construction is hoped be used to find new convolutional codes that would allow for less storage requirements for larger codes. This may be extended to consider LDPC convolutional codes and turbo codes.
Darwinian Dynamics Implies Developmental Ascendency

A tendency in biological theorizing is to formulate principles above or equal to Evolution by Variation and Selection of Darwin and Wallace. In this letter I analyze one such recent proposal which did so for the developmental ascendency. I show that though the idea of developmental ascendency is brilliant, this is in wrong order in the hierarchical structure of biological theories and can easily generate confusing. Several other examples are also briefly discussed in the note added.
A Statistical Method for Estimating Luminosity Functions Using Truncated Data

The observational limitations of astronomical surveys lead to significant statistical inference challenges. One such challenge is the estimation of luminosity functions given redshift (z) and absolute magnitude (M) measurements from an irregularly truncated sample of objects. This is a bivariate density estimation problem; we develop here a statistically rigorous method which (1) does not assume a strict parametric form for the bivariate density; (2) does not assume independence between redshift and absolute magnitude (and hence allows evolution of the luminosity function with redshift); (3) does not require dividing the data into arbitrary bins; and (4) naturally incorporates a varying selection function. We accomplish this by decomposing the bivariate density (z,M) via log (z,M) = f(z) + g(M) + h(z,M,θ), where f and g are estimated nonparametrically and h takes an assumed parametric form. There is a simple way of estimating the integrated mean squared error of the estimator; smoothing parameters are selected to minimize this quantity. Results are presented from the analysis of a sample of quasars.
Ground-Based Response of a Spinning, Cyclic Symmetric Rotor Assembled to a Flexible Stationary Housing Via Multiple Bearings

This paper is to study free response of a spinning, cyclic symmetric rotor assembled to a flexible housing via multiple bearings. In particular, the rotor spins at a constant speed ω3, and the housing is excited via a set of initial displacements. The focus is to study ground-based response of the rotor through theoretical and numerical analyses. The paper consists of three parts. The first part is to briefly summarize an equation of motion of the coupled rotor-bearing-housing systems for the subsequent analyses. The equation of motion, obtained from prior research [1], employs a ground-based and a rotor-based coordinate system to the housing and the rotor, respectively. As a result, the equation of motion takes the form of a set of ordinary differential equations with periodic coefficients of frequency ω3. To better understand its solutions, a numerical model is introduced as an example. In this example, the rotor is a disk with four radial slots and the housing is a square plate with a central shaft. The rotor and housing are connected via two ball bearings. The second part of the paper is to analyze the rotor’s response in the rotor-based coordinate system theoretically. When the rotor is at rest, let ωH be the natural frequency of a coupled rotor-bearing-housing mode whose response is dominated by the housing. The theoretical analysis then indicates that response of the spinning rotor will possess frequency components ωH ± ω3 demonstrating the interaction of the spinning rotor and the housing. The theoretical analysis further shows that this splitting phenomenon results from the periodic coefficients in the equation of motion. The numerical example also confirms this splitting phenomenon. The last part of the paper is to analyze the rotor’s response in the ground-based coordinate system. A coordinate transformation shows that the ground-based response of the spinning rotor consists of two major frequency branches ωH − (k + 1) ω3 and ωH − (k − 1) ω3, where k is an integer determined by the cyclic symmetry and vibration modes of interest. The numerical example also confirms this derivation.Copyright © 2013 by ASME
Development of an Effective Rent (Lease) Index for the Chicago CBD

Abstract This paper estimates changes in effective rental rates for the period 1985 to 1991 for office space in the Chicago central business district (CBD) using information from individual leases provided by the Koll/Rubloff Company. This is the first study to use detailed lease-level data to estimate a price index for changes in effective rents for a metropolitan area. Effective rents are estimated from the perspective of the property owners and are defined as the annual-equivalent cash flows of the present value of all cash flows that are explicitly identified in the lease contracts; including the contract rental rate, graduations in the contract rate, tenant improvements, moving allowances, buyout allowances, expense stops, broker commissions, and any other conditions of the lease that generate specific dollar receipts or expenditures for the owner. A real estate index based on changes in effective rents rather than property values is unaffected by changes in market capitalization rates and therefore provides a measure of changes in the market for space that is independent of changes in the market for capital. The results suggest that effective rents in the Chicago CBD declined almost 50% from 1985 to 1988 and increased only slightly from 1988 to 1991. Asking rents, on the other hand, were fairly constant over the same time interval. The average of the base (contract) rents from the sample of leases in this study was lower than the average asking rents (as might be expected) and were more volatile through time. Base rents were greater (and had less volatility) than effective rents, however, due to the use of free rent and other concessions which appear to increase when the market weakens and decrease when the market strengthens. As a result, effective rents have much more volatility and provide a more accurate and timely representation of trends in the price of space than either asking rents or contract rents.
Reduction of Delay between Particle Passage and Spark Chamber Spark

The delay time between the passage of an ionizing particle and the spark-chamber spark is one of the limiting factors in the time resolution of spark-chamber systems. The usual resolving time is of the order of 0.5 ?sec. The delay time in photomultipliers, cables, coincidence mixers, high voltage pulse generators, spark gaps, spark chamber voltage rise, and spark formation is investigated. Elements of a system are described which result in a total delay of about 33 nsec, including the photomultiplier. This may permit a reduction in spark chamber memory time and time resolution by about one order of magnitude. The reduction in delays and rise times also decreases the displacement of tracks in spark chambers operating in a magnetic field.
Robust controller designs for second-order dynamic systems - A virtual passive approach

This paper presents a robust controller design for second-order dynamic systems. The controller is model independent and is a virtual second-order dynamic system. The conditions for actuator and sensor placements are identified for controller designs that guarantee overall closed-loop stability. The dynamic controller can be viewed as a virtual passive damping system that serves to stabilize the actual dynamic system. The control gains are interpreted as virtual mass, spring, and dashpot elements that play the same roles as actual physical elements in stability analysis. Position, velocity, and acceleration feedback are considered. Simple examples are provided to illustrate the controller design. From this illustration the physical meaning of the controller design is apparent.
Diastereoselectivities in the diels-alder reactions of cyclopentadiene with optically active dimenthyl fumarate and menthyl methyl fumarate in LiClO4/ether and on Al2O3

Abstract Reactions of cyclopentadiene with (−)-dimenthyl fumarate, which yield adducts 1 and 2 , and with (−)-menthyl methyl fumarate, which yield adducts 3 through 6 , were carried out on alumina activated at different temperatures, in LiClO 4 /ether solutions, and in other media. Various diastereoselectivities - 2:1,3:4, 6:5 , endo:exo [( 3 + 4 ): ( 5 + 6 )], and % de [( 3 + 6 ) - ( 4 + 5 )]/[ 3 + 4 + 5 + 6 ] × 100] - were determined for these reactions. The LiClO 4 data were analyzed using a model in which LiClO 4 reversibly binds to the dienophile, resulting in competing catalyzed and uncatalyzed Diels-Alder reactions. Even in approximately 5 M LiClO 4 , there are sizable contributions from uncatalyzed reactions in all cases. Extrapolation of the data to infinite LiClO 4 concentration yields data for the catalyzed reactions alone; only modest diastereoselectivities are seen for the catalyzed reactions. The alumina results were unusual because the endo:exo ratios of adducts were large but % de's were small. The selectivities on alumina could not be correlated to the activity of the solid. This behavior will occur when varying numbers and types of catalytic sites are exposed to the surface on activation.
A direct absorber reactor/receiver for solar thermal applications

Abstract A novel catalytic reactor concept is described in which concentrated radiant (solar) energy is directly absorbed at the catalytic reaction sites, thereby avoiding the heat-transfer limitations of conventional tubular reactors for high-flux conditions. Results from a detailed numerical model of a direct catalytic adsorption reactor illustrate unique features of the reactor and critical design requirements of the volumetric absorber. Numerical predictions compare well with preliminary experimental data for carbon dioxide reforming of methane to synthesis gas. Thermal and chemical conditions of the absorber for a large-scale reactor under typical high-flux operation are shown.
Groups with a character of large degree

Let G be a finite group of order n and V a simple C[G]-module of dimension d. For some nonnegative number e, we have n = d(d +e). If e is small, then the character of V has unusually large degree. We fix e and attempt to classify such groups. For e < 3 we give a complete classification. For any other fixed e we show that there are only finitely many examples.
Lower bound on the propagation speed of gravity from gravitational Cherenkov radiation

Recently, interesting 4-D Lorentz violating models have been proposed, in which all particles have a common maximum velocity c, but gravity propagates (in the preferred frame) with a different maximum velocity cg≠c. We show that the case cg < c is very tightly constrained by the observation of the highest energy cosmic rays. Assuming a galactic origin for the cosmic rays gives a conservative bound of c−cg <2 × 10−15c; if the cosmic rays have an extragalactic origin the bound is orders of magnitude tighter, of order c−cg < 2 × 10−19c.
Production of low- and high-energy radioactive-ion beams by fragmentation

The physics opportunities made possible by beams of rare isotopes are among the richest available in nuclear science. The rare-isotope accelerator (RIA) now under development is an innovative accelerator that will define the state of the art for all such facilities. A novel aspect of the RIA project is the conversion of the most intense high-energy heavy-ion beams into both fast and reaccelerated exotic beams. Along with target fragmentation in next-generation high-power ISOL targets, RIA will use projectile fragmentation in a high-energy separator/gas-filled ion collector system to provide an extensive range of thermalized ions for reacceleration. In addition, a second high-energy separator will provide the same or larger range of ions for high-energy experiments. A brief overview of the RIA accelerator concept, the layout of the facility, and production techniques will be given along with information on the present R&D efforts in gaseous-ion collection.
Buying a house and the decision to use a real estate broker

This study examines the factors that affect the decision by home buyers to use real estate brokers and the subsequent effect this decision has on home prices. Buyers with high opportunity costs and the least amount of information about local market conditions are the most likely to use brokers; a finding consistent with the role of the real estate broker as a market intermediary. Not surprisingly, these were some of the same factors that also have a positive impact on selling price. An important finding of this study is that when selection bias is adequately controlled, the real estate broker has no appreciable, independent impact on selling price. This, in turn, suggests a nonsegmented, highly competitive housing market.
Beyond the Sunan Model: Trajectory and Underlying Factors of Development in Kunshan, China:

Since the launch of economic reforms in the late 1970s, some cities and regions in China have been growing much faster than others, stimulating scholarly research on the forces underlying uneven development. This paper, through a case study of the emergence of Kunshan in southern Jiangsu (Sunan), shows that the orthodox Sunan model centered on the development of township and village enterprises (TVEs) has become inadequate to account for the recent development and restructuring in Sunan. I argue that spatial development in China is a complicated process incorporating the role of the state, local development conditions, and foreign investment. Moreover, there are strong geographical foundations for the functioning of local states. The arguments are particularly relevant to the transitional nature of provincial China, where the state still plays a significant role in development while local and global forces have emerged as equally important forces.
Modern energy density functional for nuclei and the nuclear matter equation of state

We discuss a method of determining a modern energy density functional (EDF) in nuclei. We adopt a Skyrme type EDF and fit the Skyrme parameters to an extensive set of experimental data on the ground-state binding energies, radii, and the breathing mode energies of a wide range of nuclei. We further constrain the values of the Skyrme parameters by requiring positive values for the slope of the symmetry energy S, the enhancement factor κ, associated with the isovector giant dipole resonance, and the Landau parameter G 0 ′ . This is done within the approaches of Hartree-Fock (HF) and HF with the inclusion of correlation effects, using a simulated-annealing based algorithm forminimizing χ 2.We also present results of HF based random phase approximation for the excitation strength function of the breathing mode and discuss the current status of the nuclear matter incompressibility coefficient.
A Solar System Survey of Forced Librations in Longitude

Forced librations are periodic rotational rate variations due to gravitational interactions with an orbital partner. We have developed an analytic theory capable of calculating expected amplitudes of forced librations for nonresonant rotators as well as for bodies existing in a spin-orbit resonance. The theory has been applied to 34 solar system bodies, including terrestrial planets, planetary satellites, and the asteroid Eros. Parameters governing libration amplitude are the body s orbital eccentricity, moment difference, and the ratio of its spin rate to its orbital rate. In each case the largest libration amplitude is associated with the forcing frequency 2 (p - 1) n, where n is the orbital mean motion and p is the spin/orbit rate ratio. This dominant frequency is simply semidiurnal as seen from the position of the torquing body. The maximum libration angular amplitude is 1.3 x 10(exp -2) radians for Thebe, and the maximum mean equatorial displacement is 1.4 km for Mimas.
A Nearly-Four-Pi Liquid Scintillation Counter for Bursts of Fast Neutrons

This liquid scintillation counter detects 14 mev neutrons by both proton-recoil and neutron-proton capture processes. It is designed to measure fast neutrons which occur in a single burst of a few microseconds duration, a burst which may contain anywhere from 100 to 100,000 neutrons. The counter is 36 inches in diameter, 36 inches long, and has an axial access cylinder 12 inches in diameter. It contains 475 liters of triethylbenzene, 2.5 grams per liter of p-terphenyl and 0.02 grams per liter of POPOP. Scintillations are detected by 20 Dumont Type 6364 multiplier phototubes. Four tubes are used as proton-recoil detectors and 16 are used as neutron-proton capture detectors. The counter was completed in January 1959, and has shown high reliability and only a relatively small change in sensitivity since it was first calibrated.
Two-photon three-dimensional memory hierarchy

The computational power of current high-performance computers is increasingly limited by data storage and recall rates. In existing sequential-access electronic memories, a hierarchy of devices from cache memory to secondary storage provides a performance continuum, allowing a balanced system design. Here we discuss the use of 3-D volume storage based on two photon materials to bridge the gaps in the storage hierarchy of parallel-access memories.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Macroscopic Flow Potentials in Swelling Porous Media

In swelling porous media, the potential for flow is much more than pressure, and derivations for flow equations have yielded a variety of equations. In this article, we show that the macroscopic flow potentials are the electro-chemical potentials of the components of the fluid and that other forms of flow equations, such as those derived through mixture theory or homogenization, are a result of particular forms of the chemical potentials of the species. It is also shown that depending upon whether one is considering the pressure of a liquid in a reservoir in electro-chemical equilibrium with the swelling porous media, or the pressure of the vicinal liquid within the swelling porous media, a critical pressure gradient threshold exists or does not.
THE HIGGS SECTOR ON A TWO-SHEETED SPACE–TIME

We present a general formalism based on the framework of noncommutative geometry, suitable to the study of the standard model of electroweak interactions, as well as that of more general gauge theories. Left- and right-handed chiral fields are assigned to two different sheets of space–time (a discretized version of Kaluza–Klein theory). Scalar Higgs fields find themselves treated on the same footing as the gauge fields, resulting in spontaneous symmetry breaking in a natural and predictable way. As a first test, we apply the formalism to the Standard Model, where one can predict the Higgs mass and the top Yukawa coupling. The results obtained for this case are similar with results obtained in alternate formulations. We then study the left–right symmetric model, where we show that this framework imposes interesting constraints on the type and coefficients of terms appearing in the Higgs potential.
Magnetism of V, Mo, and Co surface impurities on Pb measured by their pair-breaking effect

Thin films of Pb are covered in situ with submonolayers of V, Mo, and Co in the range between 0.01 and 1 monolayers. If the surface impurities are magnetic they will reduce the superconducting transition temperature of the Pb film. From the reduction of ${T}_{c}$ the magnetic dephasing rate of the surface impurities $1/{\ensuremath{\tau}}_{s}$ and their magnetic cross section ${\ensuremath{\sigma}}_{s}$ are calculated. We find that single V surface impurities are magnetic, while single Mo and Co impurities are nonmagnetic. Co surface clusters are magnetic.
Strategic HR configurations and organizational performance

Over time organizations form stable operating configurations that influence their actions in the marketplace. These configurations are shaped by interactions among variables in four areas: operating environment, business strategy, HRM practices, and senior managers' values and behaviors regarding employees. More often than not they emerge in a piecemeal rather than planned fashion. However, once established, the configurations or patterns guide employee behavior, are resistant to change, and are associated with different levels of organization effectiveness. HR managers may use these configurations to diagnose their organizations' present state and orchestrate changes to increase competitive advantage. © 2000 John Wiley & Sons, Inc.
Advances in High-Power RF Amplifiers

Several powerful accelerators and storage rings are being considered that will require tens or even hundreds of megawatts of continuous rf power. The economics of such large machines can be dictated by the cost and efficiency of the rf amplifiers. The overall design and performance of such narrow-band amplifiers, operating in the 50- to 1500-MHz region, are being theoretically studied as a function of frequency to determine the optimum rf amplifier output power, gain, efficiency, and dc power requirements. The state of the art for three types of amplifiers (gridded tubes, klystrons, and gyrocons) is considered and the development work necessary to improve each is discussed. The gyrocon is a new device, hence its various embodiments are discussed in detail. The Soviet designs are reviewed and the gyrocon's strengths and weaknesses are compared to other types of microwave amplifiers. The primary advantages of the gyrocon are the very large amount of power available from a single device and the excellent efficiency and stable operation. The klystron however, has much greater gain and is simpler mechanically. At very low frequencies, the small size of the gridded tube makes it the optimum choice for all but the most powerful systems.
COMMUTATION CLASSES OF DOUBLE WIRING DIAGRAMS

We describe a new method for computing the graph of commuta- tion classes of double wiring diagrams. Using these methods we compute the graph for ve strings or less which allows us to conrm a positivity conjecture of Fomin and Zelevinsky when n 4 .
Binding Energy and the Fundamental Plane of Globular Clusters

This paper develops a physical description of the fundamental plane of Galactic globular clusters that explains all empirical trends and correlations in a large number of cluster observables and provides a small but complete set of truly independent constraints on theories of cluster formation and evolution in the Milky Way. In a very good first approximation, the internal structures and dynamics of Galactic globulars are described by single-mass, isotropic King models and are thus characterized by four nominally independent physical parameters. Within this theoretical framework, it is shown that (1) 39 regular (non-core-collapsed) globulars with measured central velocity dispersions all share a common core mass-to-light ratio, V,0 = 1.45 M☉ L, and (2) 109 regular globulars both with and without direct observations of V,0 show a very strong correlation between global binding energy and total luminosity, regulated by Galactocentric position: Eb = 7.2 × 1039 ergs(L/L☉)2.05(rgc/8 kpc)-0.4. The observational scatter about either of these two constraints can be attributed fully to random measurement errors, making them the defining equations of a fundamental plane (FP) to which real clusters are confined in the larger, four-dimensional parameter space of general King models. They are shown to underlie a pair of bivariate correlations first found, and used to argue for the existence of a globular cluster FP, by Djorgovski. A third, weaker correlation, between clusters' total luminosities and King-model concentration parameters, is related to the (nonrandom) distribution of globulars on the FP. With L, V,0, Eb, and the central concentration c thus chosen as the four physical quantities that define any single globular cluster, the FP equations for V,0 and Eb(L,rgc) are used to derive expressions for any other observable in terms of only L, rgc, and c. Results are obtained for generic King models and applied specifically to the globular cluster system of the Milky Way.
Rectourethral Fistulae: The Perineal Approach

Editorial Comment: Rectourethral fistulas are usually iatrogenic, occurring after treatment of prostatic disease. Fecal diversion is essential in complex cases and controversial in others. While an initial trial of fecal and urinary diversion alone may promote spontaneous closure, many patients will require open surgery. The authors describe excellent outcomes using a perineal approach via a prone jackknife position, conducted by a colorectal and urological surgeon. This transsphincteric approach allows repair of the rectal and urethral aspects of the fistula, including any complex membranoprostatic urethral damage. It is interesting that in several patients subsequent artificial sphincter implantation was successful despite extensive bulbar urethral mobilization during fistula repair.
A Valid and Fast Spatial Bootstrap for Correlation Functions

In this paper we examine the validity of nonparametric spatial bootstrap as a procedure to quantify errors in estimates of N-point correlation functions. We do this by means of a small simulation study with simple point process models and estimating the two-point correlation functions and their errors. The coverage of confidence intervals obtained using bootstrap is compared with those obtained from assuming Poisson errors. The bootstrap procedure considered here is adapted for use with spatial (i.e., dependent) data. In particular, we describe a marked point bootstrap where, instead of resampling points or blocks of points, we resample marks assigned to the data points. These marks are numerical values that are based on the statistic of interest. We describe how the marks are defined for the two- and three-point correlation functions. By resampling marks, the bootstrap samples retain more of the dependence structure present in the data. Furthermore, this method of bootstrap can be performed much quicker than some other bootstrap methods for spatial data, making it a more practical method with large data sets. We find that with clustered point data sets, confidence intervals obtained using the marked point bootstrap has empirical coverage closer to the nominal level than the confidence intervals obtained using Poisson errors. The bootstrap errors were also found to be closer to the true errors for the clustered point data sets.
Protecting public pension funds from divestment-related lawsuits: Exploring the state laws of the United States

Imagine: You are a public pension fund trustee, employee or investment advisor. The legislature of your state passes a law that requires you to divest some or all of your stock holdings in companies that do business with a specific country. You seek the advice of an outside research firm that specializes in the identification of such companies. You also seek advice from an in-house or contracted counsel to determine the lawful course of action. You then proceed with the state-mandated divestments and sell your holdings. As a result, the fund's performance suffers. Should you, and those who helped you make the divestment decision, be held liable by the pensioners and other beneficiaries claiming that you have breached your fiduciary duty? This article argues not. The article finds that while most states that have divestment laws against companies that do business in Cuba, Iran, Sudan and Syria do provide some level of lawsuit protection for public fund employees, the degree of protection varies significantly. The study ranks the states’ protection levels and proposes that the higher-ranked jurisdictions serve as models for the others.
Querying multimedia presentations

We examine the querying requirements of large libraries of multimedia presentations. Given these requirements, we examine work on querying temporal and sequence data, and identify the similarities and dissimilarities between presentations and these other forms of data. From this analysis, we propose an integrated composition and query capability to permit the reuse of multimedia objects, presentations and presentation segments. The query facility permits content and attribute based queries along with queries over temporal synchronisation characteristics. The main contributions of our work are: it addresses both determinant and indeterminant intervals; it permits querying over presentation libraries with heterogeneous structure; it builds on work from temporal and sequence database to address the unique semantics of presentations.