cssi/SciSciGPT-SciSciNet huggingface dataset:
T parity and the littlest Higgs

We construct T-parity invariant extensions of the littlest Higgs model, in which only linear representations of the full symmetry group are employed, without recourse to the non-linear representations introduced by Coleman, Callan, Wess, and Zumino (CCWZ). These models are based on the symmetry breaking pattern SU(5)l × Hr/SO(5), where Hr can be SO(5) or other larger symmetry groups. The structure of the models in the SU(5)l sector is identical to the littlest Higgs model based on SU(5)/SO(5). Since the full symmetry group is realized linearly, these models can be thought of as possible UV extensions of the T-invariant model using non-linear representations via CCWZ, with whom they share similar low energy phenomenology. We also comment on how to avoid constraints from four-fermion operators on T-invariant models with or without CCWZ construction. The electroweak data therefore place a very weak bound on the symmetry breaking scale, f ≥ 450 GeV.
The Reduction of Azides with Borohydride Supported on an Ion Exchange Resin

Abstract Borohydride supported on an ion exchange resin in methanol reduced aryl azides and arylsulfonyl azides to the corresponding aromatic amines and aryl sulfonamides in excellent yields. The isolation of pure products by simple filtration and evaporation is an important feature of this method.
Biological denitrification in a continuous flow membrane reactor

Abstract Biological denitrification in a bench-scale continuous flow membrane reactor has been investigated. The nitrate-laden water treated was separated from the suspended denitrifying culture by a 0.02 μ m average pore diameter membrane. Equal pressure was maintained across the membrane and nitrate was removed by molecular diffusion through the membrane and into the denitrifying culture. A nitrate removal efficiency of approximately 90% or a flux of 4 g NO 3 − –N/m 2 /d of membrane area was achieved with an influent concentration of 20 mg/l NO 3 − –N. A mathematical model was developed to approximate system performance. Predicted effluent concentrations for the experiments conducted were 5.7, 9.5, 11.7 and 17.6 mg/l NO 3 − –N. The respective measured effluent concentrations were 2.3, 6.0, 9.0 and 16.0 mg/l NO 3 − –N.
K-user interference channels: Achievable secrecy rate and degrees of freedom

In this work, we consider achievable secrecy rates for symmetric K-user (K ≥ 3) interference channels with confidential messages. We find that nested lattice codes and layered coding are useful in providing secrecy for these channels. Achievable secrecy rates are derived for very strong interference. In addition, we derive the secure degrees of freedom for a range of channel parameters. As a by-product of our approach, we also demonstrate that nested lattice codes are useful for K-user symmetric interference channels without secrecy constraints in that they yield higher degrees of freedom than previous results.
Polarizing Gas at Small Optical Depths around Algols

The origins of visible-band linear polarimetry of Algols and objects related to them are reviewed. It is pointed out, not for the first time, that the polarization signals of these systems can vary sporadically by significant amounts. The difficulty of evaluating the interstellar component of the observed polarization is discussed and these components are evaluated anew for each object studied in this paper. With one possible exception, the polarization signals intrinsic to these binaries derive from electron scattering. A well-defined model is applied to the constant and variable (but phase-locked) polarization signals. Limits to the mass associated with a scattering disk in each binary are derived. Within broad limits, concentrations of scattering mass within and above or below the orbital plane are also developed as are the centroid longitudes of these concentrations within the system. It is pointed out that very few measures of visible-band, circular polarization have been made but that cm-wavelength measures of Algol itself have been very informative.
Reversibility of Whole-Plane SLE

The main result of this paper is that, for $$\kappa \in (0,4]$$ , whole-plane SLE $$_\kappa $$ satisfies reversibility, which means that the time-reversal of a whole-plane SLE $$_\kappa $$ trace is still a whole-plane SLE $$_\kappa $$ trace. In addition, we find that the time-reversal of a radial SLE $$_\kappa $$ trace for $$\kappa \in (0,4]$$ is a disc SLE $$_\kappa $$ trace with a marked boundary point. The main tool used in this paper is a stochastic coupling technique, which is used to couple two whole-plane SLE $$_\kappa $$ traces so that they overlap. Another tool used is the Feynman–Kac formula, which is used to solve a PDE. The solution of this PDE is then used to construct the above coupling.
Valuing Ecosystem Services with Fishery Rents: A Lumped-Parameter Approach to Hypoxia in the Neuse River Estuary

Valuing ecosystem services with microeconomic underpinnings presents challenges because these services typically constitute nonmarket values and contribute to human welfare indirectly through a series of ecological pathways that are dynamic, nonlinear, and difficult to quantify and link to appropriate economic spatial and temporal scales. This paper develops and demonstrates a method to value a portion of ecosystem services when a commercial fishery is dependent on the quality of estuarine habitat. Using a lumped-parameter, dynamic open access bioeconomic model that is spatially explicit and includes predator-prey interactions, this paper quantifies part of the value of improved ecosystem function in the Neuse River Estuary when nutrient pollution is reduced. Specifically, it traces the effects of nitrogen loading on the North Carolina commercial blue crab fishery by modeling the response of primary production and the subsequent impact on hypoxia (low dissolved oxygen). Hypoxia, in turn, affects blue crabs and their preferred prey. The discounted present value fishery rent increase from a 30% reduction in nitrogen loadings in the Neuse is $2.56 million, though this welfare estimate is fairly sensitive to some parameter values. Surprisingly, this number is not sensitive to initial conditions.
Incentive compatibility constraints as an explanation for the use of prison sentences instead of fines

In standard models of optimal deterrence, which assume perfect information on the part of the social planner, fines dominate jail sentences as an instrument for punishing crime. In the real world, however, punishment using prisons is quite common. This paper provides an explanation for that empirical observation. If criminals either have private information about their own wealth, or have a substantial portion of their wealth in the form of human capital, the social planner cannot simply impose a fine on a criminal, who can always claim to have insufficient wealth to pay the fine. Rather, because of the need for incentive compatibility, it is as if the social planner offers the criminal a choice: either pay the fine or go to jail. That additional constraint on the social planner dramatically reduces the effectiveness of fines vis-a-vis a perfect information world. Mandatory sentencing guidelines exacerbate the problems associated with incentive compatibility by restricting a judge's ability to tailor penalties to individual criminals.
A threat–response multi-criteria funding model for homeland security grant programs

The Department of Homeland Security (DHS) provides funding to 50 states, the District of Columbia, and seven US territories through a consolidated program called the Homeland Security Grant Program (HSGP). There has been much controversy about the lack of structure in HSGP and the method it employs to allocate funds to the states and territories. Slice is a threat–response multi-criteria decision model that systematically evaluates the threats and responses of securing the states and territories. The Analytic Hierarchy Process (AHP) and probability elicitation methods are used to capture the objective and subjective judgments used in Slice. The probability calibration and entropy methods are used along with the utility theory to obtain a composite weighted score for each state and territory. These weighted scores are combined with the population scores in a structured framework to determine the amount of funding for the states and territories.
Error-Covariance Analysis of the Total Least-Squares Problem

This paper derives and analyzes the estimate error covariances associated with both the nonstationary and stationary noise process cases with uncorrelated elementwise components for the total least-squares problem. The nonstationary case is derived directly from the associated unconstrained total least-squares loss function. The stationary case is derived by using a linear expansion of the total least-squares estimate equation, which involves a first-order expansion of the associated singular value decomposition matrices. The actual solution for the error covariance is evaluated at the true variables, which are unknown in practice. Two common approaches to overcome this difficulty are used; the first involves using the measurements directly and the second involves using the estimates, which are more accurate than the measurements. This paper shows that using the latter greatly simplifies the error-covariance solution for the stationary case. Simulation results using bearings-only point estimation are show...
Interaction of Sound from Supersonic Jets with Nearby Structures

We numerically solve a model of sound generated in an ideally expanded two-dimensional supersonic (Mach 2) jet. Two configurations are considered: 1) a free jet and 2) an installed jet with a nearby array of flexible aircraft type panels. In the later case the panels vibrate in response to loading by sound from the jet, and the full coupling between the panels and the jet is simulated, accounting for panel response and radiation as well as the jet acoustics. We consider the long time behavior of the jet/panel system and present results for the flowfield and far-field pressure and the vibration of, and radiatlon from, the panels. The pressure within the jet changes from a nearly discrete spectrum peaked at a preferred frequency f * , which depends on properties of the jet, to a continuous spectrum as downstream distance increases. The far-field pressure is characterized by a highly directional beaming of sound with a spectral peak at f * within the Mach line and a lower-level breakup into small-scale structures away from the Mach line. We show that the location of the panels relative to the Mach line is critical in determining panel response. Panels located upstream of the Mach line are subject to a low-level continuous spectrum loading and exhibit a comparable response. In contrast, panels located within the Mach line are subject to a high-level loading due to the intense Mach wave radiation of sound peaked at f * and exhibit a comparable response. The panels radiate in a simil ion to the sound in the particular, the is a strong beaming of sound waves at frequency f * from the ex ted panels Mach-angle-from the bounding wall, indicating a significant effect of Mach wave radiation both interior spectral content in the supersonic regime.
Using the Two-Branch Tournament Genetic Algorithm for Multiobjective Design

The two-branch tournament genetic algorithm is presented as an approach to determine a set of Pareto-optimal solutions to multiobjective design problems. Because the genetic algorithm searches using a population of points rather than using a point-to-point search, it is possible to generate a large numher of solutions to multiobjective problems in a single run of the algorithm. The two-branch tournament and its implementation in a genetic algorithm (GA) to provide these solutions are discussed. This approach differs from most traditional methods for GA-based multiobjective design ; it does not require the nondominated ranking approach nor does it require additional fitness manipulations. A multiobjective mathematical benchmark problem and a 10-bar truss problem were solved to illustrate how this approach works for typical multiobjective problems. These problems also allowed comparison to published solutions. The two-branch GA was also applied to a problem combining discrete and continuous variables to illustrate an additional advantage of this approach for multiobjective design problems. Results of all three problems were compared to those of single-objective approaches providing a measure of how closely the Pareto-optimal set is estimated by the two-branch GA. Finally, conclusions were made about the benefits and potential for improvement of this approach.
Mean field kinetic theory for a lattice gas model of fluids confined in porous materials

We consider the mean field kinetic equations describing the relaxation dynamics of a lattice model of a fluid confined in a porous material. The dynamical theory embodied in these equations can be viewed as a mean field approximation to a Kawasaki dynamics Monte Carlo simulation of the system, as a theory of diffusion, or as a dynamical density functional theory. The solutions of the kinetic equations for long times coincide with the solutions of the static mean field equations for the inhomogeneous lattice gas. The approach is applied to a lattice gas model of a fluid confined in a finite length slit pore open at both ends and is in contact with the bulk fluid at a temperature where capillary condensation and hysteresis occur. The states emerging dynamically during irreversible changes in the chemical potential are compared with those obtained from the static mean field equations for states associated with a quasistatic progression up and down the adsorption/desorption isotherm. In the capillary transition region, the dynamics involves the appearance of undulates (adsorption) and liquid bridges (adsorption and desorption) which are unstable in the static mean field theory in the grand ensemble for the open pore but which are stable in the static mean field theory in the canonical ensemble for an infinite pore.
Separating the Hawks from the Doves: Evidence from continuous time laboratory games ☆

Human players in our laboratory experiment received ow payos over 120 seconds each period from a standard Hawk-Dove bimatrix game played in continuous time. Play converged closely to the symmetric mixed Nash equilibrium under a one-population matching protocol. When the same players were matched in a two-population protocol with the same bimatrix, they showed clear movement towards an asymmetric (and very inequitable) pure Nash equilibrium of the game. These ndings support distinctive predictions of evolutionary game theory.
Electromagnetic structure of the deuteron

Recent high energy measurements of elastic ed scattering support the use of a relativistic theory based on an accurate description of the NN channel, but theory needed for an understanding of the high energy deuteron photodisintegration cross sections and polarized observables is not yet mature.
Hyperbolic localization of intersection cohomology

For a normal variety X defined over an algebraically closed field with an action of the multiplicative group T = Gm, we consider the "hyperbolic localization" functor Db(X) → Db(XT), which localizes using closed supports in the directions flowing into the fixed points, and compact supports in the directions flowing out. We show that the hyperbolic localization of the intersection cohomology sheaf is a direct sum of intersection cohomology sheaves.
Knowledge Transfer Under Subcontracting: Evidence from Czech Firms

Abstract We investigate the significance of subcontracting arrangements as a source of knowledge transfer and increased efficiency for Czech firms during 1993–96. We draw on detailed enterprise surveys and interviews with the managers of 373 manufacturing firms in the Prague region. The results suggest a positive correlation between employee training and subcontracting. Subcontracting is also associated with a reduction in variable costs and a price premium on the stock market. The effect of subcontracting on other firms in the same industry is weak. A high share of subcontracting activity in a particular industry is associated with increased valuation of firms without foreign partners as investors anticipate more subcontracting arrangements.
Experimental demonstration of static shape control

Results of a microprocessor-controlled implementation of static shape control using a specially constructed flexible beam facility are presented. The discussion covers the development of shape control algorithms, adaptation of the algorithms for use with finite element models, construction of a flexible beam, characterization and calibration of the facility, development of a finite element model for the beam, and the development of computer hardware and software. It is shown that feedback control yields better results than open-loop control, and that the use of more than two sensors in the control loop has little effect on the system performance.
Raman laser amplification in preformed and ionizing plasmas

The recently proposed backward Raman laser amplification scheme utilizes the stimulated Raman backscattering in plasma of a long pumping laser pulse to amplify a short, and frequency downshifted seed pulse. The output intensity for this scheme is limited by the development of forward Raman scattering ~FRS! or modulational instabilities of the highly amplified seed. Theoretically, focused output intensities as high as 10 25 W0cm 2 , and pulse lengths of less than 100 fs, could be accessible by this technique for 1 mm lasers—an improvement of 10 4 ‐10 5 in focused intensity over current techniques. Simulations with the particle-in-cell ~PIC! code Zohar are presented, which investigate the effects of FRS and modulational instabilities, and of Langmuir wave breaking on the output intensity for Raman amplification. Using the intense seed pulse to photoionize the plasma simultaneous with its amplification ~and hence avoid plasmas-based instabilities of the pump! is also investigated by PIC simulations. It is shown that both approaches can access focused intensities in the 10 25 W0cm 2 range.
Subjectivity and cultural critique

In the many works that try to bring back ‘the actor’ in some sense, there is a tendency to avoid questions of subjectivity, that is, complex ‘structures of feeling’ (in Raymond Williams’s phrase). This article returns to the work of Max Weber and Clifford Geertz to consider various issues of subjectivity, including both fundamental existential anxieties, and specific cultural and historical constructions of ‘consciousness’. The article concludes with a rereading of several recent texts on postmodern consciousness as a specific configuration of anxieties, tied in turn to formations of ‘late capitalism’.
Promoter CpG Hypomethylation and Transcription Factor EGR1 Hyperactivate Heparanase Expression in Bladder Cancer

Heparanase plays a critical role in the degradation of extracellular matrix and cell membrane and is frequently upregulated in malignant tumors. Transcription factor, early growth response 1 (EGR1), is closely associated with inducible transcription of the heparanase gene. We hypothesized that promoter CpG hypomethylation with increased EGR1 expression could determine heparanase expression during the pathogenesis of bladder cancer. Bladder cancer cell lines (J82, T24 and transitional cell carcinoma) significantly restored heparanase expression after 5-Aza-dC treatment. Transfection of EGR1 siRNA with T24 bladder cancer cell line significantly downregulated heparanase expression compared to the control siRNA transfection. In 54 bladder cancer and paired normal bladder samples, heparanase expression was significantly higher in bladder cancer than in normal bladder (P<0.01). We performed methylation-specific PCR targeting the CpG sites within the core-binding consensus motifs of EGR1 (GGCG) and Sp1 (GGGCGG). Methylation prevalence was significantly higher in normal bladder than in bladder cancer (P<0.05) and inversely correlated with heparanase expression (P=0.055). In the total series of bladder cancer and normal bladder samples, the combination of promoter CpG methylation and EGR1 expression regulated heparanase expression in a stepwise manner, where heparanase expression was the lowest in methylation-positive and EGR1-negative samples and the highest in methylation-negative and EGR1-positive samples. To our knowledge, this is the first study demonstrating that increased heparanase expression during the pathogenesis of bladder cancer is due to promoter hypomethylation and transcription factor EGR1.
Practising ‘Democracy’ in Nigerian Films

This article discusses the response of ‘Nollywood’ to the transformation of Nigeria's social structure through the economic and political regimes of global neo-liberalism and Nigeria's military rule, and the aesthetic possibilities enabled by video and digital technologies. Approaching Nollywood as a new cinematic form which results from the collapse of the middle classes due to radical economic reforms, the article looks at two films, Akobi Gomina (‘The Governor's Heir’, 2002) and Agogo Eewo (‘The Sacred Gong’, 2002) to demonstrate the implications of this phenomenon in the changing socio-political structure crystallized with the advent of the Fourth Republic in 1999. In these works of explicit and oblique political commentary, which present us with intimations of the genre of ‘democracy films’, the idea of a public receptive to mutually recognized cultural or personal symbols is used to develop new aesthetic modes in films. But these film-making practices also circumscribe the possibilities of an ideologically progressive cinematic practice. Thus, a form originating partly from an economic context appears caught in an aesthetic impasse, but the article suggests that the tendency in Nollywood toward generic proliferation might represent one path out of the impasse.
Search for the H particle: Its production and weak decay

Jaffe has suggested that a six-quark state with the flavor content of two-lambda hyperons with all spins coupled to zero, the H particle, may be bound against strong decay. This particle has become the object of extensive discussion in the literature and of several experimental searches. We report here the present status of an investigation of the reaction: ({Xi}{minus},d){sub atom}{yields} H + n in experiment E-813 at the BNL-AGS and describe plans for future running in 1992.
Synthesis of Fused-Ring and Attached-Ring bis-Tetrahydrofurans via Pd-Catalyzed Carboetherification

A five step-synthesis of fused bis-tetrahydrofurans and attached bis-tetrahydrofurans from butadiene diepoxide is described. Two sequential Pd-catalyzed carboetherification reactions between protected 1,2-diols and aryl/alkenyl bromides, each of which form both a C−O bond and a C−C bond, are used to generate the heterocyclic rings with >20:1 dr. Installation of different R1 and R2 groups is achieved in a straightforward fashion through use of different aryl or alkenyl bromide coupling partners.
New Generation Atmospheric Cherenkov Detectors

Abstract High energy γ-ray astronomy has been established during the last decade through the launch of the Compton Gamma Ray Observatory (CGRO) and the success of its ground-based counterpart, the imaging atmospheric Cherenkov technique. In the aftermath of their important and surprising scientific results a worldwide effort developing and designing new generation atmospheric Cherenkov detectors is underway. These novel instruments will have higher sensitivity at E > 250 GeV, but most importantly, will be able to close the unexplored energy gap between 20 GeV and 250 GeV. Several ground-based detectors are proposed or under construction. Aspects of the techniques used and sensitivity are discussed in this overview paper. The instruments cover largely complementary energy ranges and together are expected to explore the γ-ray sky between 20 GeV and 100 TeV with unprecedented sensitivity.
Lyapunov stability, semistability, and asymptotic stability of matrix second-order systems

Necessary and sufficient conditions for Lyapunov stability, semistability and asymptotic stability of matrix second-order systems are given in terms of the coefficient matrices. Necessary and sufficient conditions for Lyapunov stability and instability in the absence of viscous damping are also given. These are used to derive several known stability and instability criteria as well as a few new ones. In addition, examples are given to illustrate the stability conditions.
An Analysis Framework for Distributed Hierarchical Directories

We provide a novel analysis framework for distributed hierarchical directories for an arbitrary set of dynamic (online) requests. We first present a generic algorithm for implementing a distributed directory that can support dynamic requests and prove an upper bound on the competitive ratio for communication cost experienced by this algorithm using the analysis framework. We then give bounds for the dynamic performance of several known distributed directory protocols. For the protocols that work in general network topologies, we obtain $\mathcal {O}(\log^{2} n\cdot\log D)$ competitive ratio, where n and D are the number of nodes and the diameter, respectively, of the network. Moreover, for the protocols that work in specific network topologies, we obtain $\mathcal {O}(\log D)$ competitive ratio. Our analysis framework captures both the time and the distance restrictions in ordering dynamic requests through a notion of time windows, which may be of independent interest. To the best of our knowledge, this is the first competitive dynamic analysis for distributed hierarchical directories.
Respite use in dementia patients

Caregivers of dementia patients often find themselves physically and emotionally exhausted. Respite care can lend the primary caregiver support. However, utilization of such service has been low. This prospective study explored patterns of institutional respite utilization over a one year time period. Fifty-eight caregivers of dementia patients treated in an outpatient memory loss clinic participated. Forty percent used respite care during the study period. Data were collected using the Burden Interview, Functional Dementia Scale, Community Service Attitude Inventory, MMSE and self-report questionnaires. Respite users were significantly more cognitively and functionally Impaired than non-users and their caregivers experienced greater burden. These same factors also predicted time to respite care use. Caregiver attitudes were not predictive of respite request or usage.
clMAGMA: high performance dense linear algebra with OpenCL

This paper presents the design and implementation of several fundamental dense linear algebra (DLA) algorithms in OpenCL. In particular, these are linear system solvers and eigenvalue problem solvers. Further, we give an overview of the clMAGMA library, an open source, high performance OpenCL library that incorporates various optimizations, and in general provides the DLA functionality of the popular LAPACK library on heterogeneous architectures. The LAPACK compliance and use of OpenCL simplify the use of clMAGMA in applications, while providing them with portable performance. High performance is obtained through the use of the high-performance OpenCL BLAS, hardware- and OpenCL-specific tuning, and a hybridization methodology, where we split the algorithm into computational tasks of various granularities. Execution of those tasks is efficiently scheduled over the heterogeneous hardware components by minimizing data movements and mapping algorithmic requirements to the architectural strengths of the various heterogeneous hardware components.
Roots of Dehn twists

Margalit and Schleimer found examples of roots of the Dehn twist t C about a nonseparating curve C in a closed orientable surface, that is, homeomorphisms h such that h n = t C in the mapping class group. Our main theorem gives elementary number-theoretic conditions that describe the n for which an n th root of t C exists, given the genus of the surface. Among its applications, we show that n must be odd, that the Margalit-Schleimer roots achieve the maximum value of n among the roots for a given genus, and that for a given odd n, n th roots exist for all genera greater than (n − 2)(n − 1)/2. We also describe all n th roots having n greater than or equal to the genus.
Evidence for Expanding Superbubbles in a Galaxy at z = 0.7443*

The intervening z = 0.7443 Mg II absorption system in the spectrum of MC 1331+170 shows an unusual series of line pairs, each with Δv ~ 30 km s-1. These lines could be explained as the shells of expanding superbubbles residing in the outer regions of an edge-on spiral galaxy visible in the optical image of the MC 1331+170 field. The color and brightness of this galaxy make it the most likely candidate z = 0.7443 absorber, though two other galaxies in the quasar field could also be contributing to the Mg II absorption profile. Kinematic models of absorption from compact groups and galaxy pairs produce profiles largely inconsistent with the observed Mg II spectrum. Superbubbles would naturally generate more regular structures, such as those observed. Photoionization models of the superbubble shell are consistent with the observed profile for many realistic physical conditions. In a pure superbubble model, the large velocity spread of the Mg II absorption system is inconsistent with the expected spread of a quiescent, rotating disk. This requires unusual kinematics within the host galaxy, perhaps due to a recent interaction.
α-(N-Carbamoyl)alkylcuprate Chemistry in the Synthesis of Nitrogen Heterocycles

The conjugate adducts obtained via coupling of α-(N-carbamoyl)alkylcuprates with α,β-ynoates, α-allenyl esters, or α,β-enoates or enimides undergo N-Boc deprotection and cyclization onto the ester functionality upon treatment with PhOH/TMSCl, catecholboron bromide, or trimethylsilyl triflate. This two-pot sequence provides synthetic routes to 4-alkylidinepyrrolidine-2-ones, 4-alkylidinepyrrolizidin-2-ones, and 4-alkylidineindolizidin-2-ones via allenyl esters; pyrrolin-2-ones, tetrahydropyrrolizin-2-ones, and tetrahydroindolizin-2-ones via α,β-ynoates; pyrrolidin-2-ones, pyrrolizidin-2-ones, and indolizidin-2-ones via α,β-enoates or α,β-enimides. The reluctance of γ-carbamoyl-α,β-enoates to undergo E/Z isomerization requires the use of (Z)-β-iodo-α,β-enoates readily prepared by the addition of HI to the alkynyl esters for the efficient preparation of pyrrolinones, tetrahydropyrrolizinones, and tetrahydroindolizinones. Utilization of ω-functionalized α,β-ynoates or β-iodo-α,β-enoates allows for cyclization...
Enterprise Productivity and Efficiency: When Is Up Really Down?☆☆☆

Abstract A substantial body of literature has documented impressive total factor productivity (TFP) growth in China's state-owned enterprises (SOEs) during the period of China's enterprise reform. Such growth rates have been used to support the view that China's reforms of SOEs have been highly successful. In this paper, we question the validity of using TFP growth rates as a “bottom line” measure of performance. In the spirit of a counterexample, we use a simple model to show that when firms are not profit maximizers for whatever reason, higher productivity may actually lead to greater allocative distortion, lower profits, and lower economic efficiency. On the basis of existing evidence, we argue that these conditions held for many Chinese state enterprises during the reform.J. Comp. Econom.,June 1997,24(3), pp. 265–280. Boston College, Chestnut Hill, Massachusetts 02167; University of Michigan, Ann Arbor, Michigan 48109-1220; and Industrial Relations Center, Carlson School of Management, University of Minnesota, 271 19th Ave. S., Minneapolis, Minnesota 55455.
Hardness Hypotheses, Derandomization, and Circuit Complexity

We consider hypotheses about nondeterministic computation that have been studied in different contexts and shown to have interesting consequences: We show that the NP-machine hypothesis is implied by each of the first two. Previously, no relationships were known among these three hypotheses. Moreover, we unify previous work by showing that several derandomizations and circuit-size lower bounds that are known to follow from the first two hypotheses also follow from the NP-machine hypothesis. In particular, the NP-machine hypothesis becomes the weakest known uniform hardness hypothesis that derandomizes AM. We also consider UP versions of the above hypotheses as well as related immunity and scaled dimension hypotheses.
Preparation of Nonsymmetrically Substituted Stilbenes in a One-Pot Two-Step Heck Strategy Using Ethene As a Reagent

We present here a strategy for the preparation of nonsymmetrically substituted stilbenes using a one-pot two-step double Heck strategy. First a protocol is developed for the selective preparation of a range of styrenes using ethene as the alkene coupling partner. Then conditions are found for the effective coupling of the styrenes with aryl halides using a 1:1 stoichiometric ratio of the two components. The use of the microwave apparatus to perform the reactions offers a convenient method for synthesis as well as for safely, easily, and accurately loading vessels with gaseous reagents.
Enhancement of pool-boiling heat transfer using nanostructured surfaces on aluminum and copper

Abstract Enhanced pool-boiling critical heat fluxes (CHF) at reduced wall superheat on nanostructured substrates are reported. Nanostructured surfaces were realized using a low temperature process, microreactor-assisted-nanomaterial-deposition. Using this technique we deposited ZnO nanostructures on Al and Cu substrates. We observed pool-boiling CHF of 82.5 W/cm 2 with water as fluid for ZnO on Al versus a CHF of 23.2 W/cm 2 on bare Al surface with a wall superheat reduction of 25–38 °C. These CHF values on ZnO surfaces correspond to a heat transfer coefficient of ∼23,000 W/m 2 K. We discuss our data and compare the behavior with conventional boiling theory.
Information content in the halo-model dark-matter power spectrum

Using the halo model, we investigate the cosmological Fisher information in the non-linear dark-matter power spectrum about the initial amplitude of linear power. We find that there is little information on ‘translinear’ scales (where the one- and two-halo terms are both significant) beyond what is on linear scales, but that additional information is present on small scales, where the one-halo term dominates. This behaviour agrees with the surprising results that Rimes & Hamilton found using N-body simulations. We argue that the translinear plateau in cumulative information arises largely from fluctuations in the numbers of large haloes in a finite volume. This implies that more information could be extracted on non-linear scales if the masses of the largest haloes in a survey are known.
COMPLEX ORGANIC MATERIALS IN THE CIRCUMSTELLAR DISK OF HR 4796A

We combine HST NICMOS imaging photometry of the HR 4796A disk at previously unobserved wavelengths between 1.71-2.22 μm with reprocessed archival observations to produce a measure of the dust's scattering efficiency as a function of wavelength. The spectrum of the dust, synthesized from the seven photometric measures, is characterized by a steep red slope increasing from 0.5 to 1.6 μm followed by a flattening of the spectrum at wavelengths >1.6 μm. We fit the spectrum with a model population of dust grains made of tholins, materials composed of complex organic materials seen throughout the outer parts of our solar system. The presence of organic material around a star that may be in the later stages of giant planet formation implies that the basic building blocks for life may be common in planetary systems.
Enhancing Hydrogen Evolution Activity in Water Splitting by Tailoring Li+-Ni(OH)2-Pt Interfaces

Improving the sluggish kinetics for the electrochemical reduction of water to molecular hydrogen in alkaline environments is one key to reducing the high overpotentials and associated energy losses in water-alkali and chlor-alkali electrolyzers. We found that a controlled arrangement of nanometer-scale Ni(OH)(2) clusters on platinum electrode surfaces manifests a factor of 8 activity increase in catalyzing the hydrogen evolution reaction relative to state-of-the-art metal and metal-oxide catalysts. In a bifunctional effect, the edges of the Ni(OH)(2) clusters promoted the dissociation of water and the production of hydrogen intermediates that then adsorbed on the nearby Pt surfaces and recombined into molecular hydrogen. The generation of these hydrogen intermediates could be further enhanced via Li(+)-induced destabilization of the HO-H bond, resulting in a factor of 10 total increase in activity.
A faster distributed protocol for constructing a minimum spanning tree

Abstract This paper studies the problem of constructing a minimum-weight spanning tree (MST) in a distributed network. This is one of the most important problems in the area of distributed computing. There is a long line of gradually improving protocols for this problem, and the state of the art today is a protocol with running time O ( Λ ( G ) + n ⋅ log ∗ n ) due to Kutten and Peleg [S. Kutten, D. Peleg, Fast distributed construction of k-dominating sets and applications, J. Algorithms 28 (1998) 40–66; preliminary version appeared in: Proc. of 14th ACM Symp. on Principles of Distributed Computing, Ottawa, Canada, August 1995, pp. 20–27], where Λ ( G ) denotes the diameter of the graph G. Peleg and Rubinovich [D. Peleg, V. Rubinovich, A near-tight lower bound on the time complexity of distributed MST construction, in: Proc. 40th IEEE Symp. on Foundations of Computer Science, 1999, pp. 253–261] have shown that Ω ˜ ( n ) time is required for constructing MST even on graphs of small diameter, and claimed that their result “establishes the asymptotic near-optimality” of the protocol of [S. Kutten, D. Peleg, Fast distributed construction of k-dominating sets and applications, J. Algorithms 28 (1998) 40–66; preliminary version appeared in: Proc. of 14th ACM Symp. on Principles of Distributed Computing, Ottawa, Canada, August 1995, pp. 20–27]. In this paper we refine this claim, and devise a protocol that constructs the MST in Ω ˜ ( μ ( G , ω ) + n ) rounds, where μ ( G , ω ) is the MST-radius of the graph. The ratio between the diameter and the MST-radius may be as large as Θ ( n ) , and, consequently, on some inputs our protocol is faster than the protocol of [S. Kutten, D. Peleg, Fast distributed construction of k-dominating sets and applications, J. Algorithms 28 (1998) 40–66; preliminary version appeared in: Proc. of 14th ACM Symp. on Principles of Distributed Computing, Ottawa, Canada, August 1995, pp. 20–27] by a factor of Ω ˜ ( n ) . Also, on every input, the running time of our protocol is never greater than twice the running time of the protocol of [S. Kutten, D. Peleg, Fast distributed construction of k-dominating sets and applications, J. Algorithms 28 (1998) 40–66; preliminary version appeared in: Proc. of 14th ACM Symp. on Principles of Distributed Computing, Ottawa, Canada, August 1995, pp. 20–27]. As part of our protocol for constructing an MST, we develop a protocol for constructing neighborhood covers with a drastically improved running time. The latter result may be of independent interest.
Characterization of Zn-promoted Rh/SiO2 catalysts by chemisorption, infrared spectroscopy, and temperature-programmed desorption

Rh/SiO{sub 2} samples with various atomic ratios of Zn to Rh were prepared by impregnation of the chlorides, followed by reduction in hydrogen. X-ray photoelectron spectra indicate that for low Zn/Rh ratios, the Zn ions are preferentially located on the surface of the Rh particles, whereas the Cl ions are efficiently removed. For high Zn/Rh ratios, ZnCl{sub 2} is deposited on the surface of the SiO{sub 2} support. The chemisorption of CO and H{sub 2} decreases with increasing Zn loading. Fourier transform infrared spectroscopy reveals that added Zn leads to a decrease in the proportion of bridging CO. Temperature-programmed desorption (TPD) shows that reactive desorption of CO to form methane is strongly depressed by Zn. These results are consistent with a model that assumes that Zn blocks the rhodium ensembles for CO dissociation and subsequent methane formation. 48 refs.
The Growth of Luminous Red Galaxies by Merging

We study the role of major and minor mergers in the mass growth of luminous red galaxies. We present small-scale (0.01 h−1 Mpc < r < 8 h−1 Mpc ) projected cross-correlation functions of 23,043 luminous early-type galaxies from the Sloan Digital Sky Survey (SDSS) luminous red galaxy (LRG) sample (0.16 < z < 0.30, M0.3 i − 5log h ≈ − 22.75 mag) with all their companions in the SDSS imaging sample, split into color and luminosity subsamples with M0.3 i − 5log h < − 18 mag. We deproject the two-dimensional functions to obtain three-dimensional real-space LRG-galaxy cross-correlation functions for each companion subsample. We find that the cross-correlation functions are not pure power laws and that there is a clear "one-halo" to "two-halo" transition near 1 h−1 Mpc. We convert these results into close pair statistics and estimate the LRG accretion rate from each companion galaxy subsample using timescales from dynamical friction arguments for each subsample of the companions. We find that the accretion onto LRGs is dominated by dry mergers of galaxies that are more luminous than L*. We integrate the luminosity accretion rate from mergers over all companion galaxy subsamples and find that LRGs are growing by 1.7 ± 0.1 h percent per Gyr, on average, from merger activity at redshift z ~ 0.25. This rate is almost certainly an overestimate, because we have assumed that all close pairs are merging as quickly as dynamical friction allows; nonetheless, it is on the low side of the panoply of measurements in the literature, and it is lower than any rate predicted from theory.
Insuring confidentiality of individual records in data storage and retrieval for statistical purposes

Much has been written about the question of privacy and the need for the protection of confidentiality of individual records in data storage and retrieval systems. The ability to insure confidentiality is a prime tool in the protection of privacy. The goal of this paper is to summarize from the point of view of a statistician some of the aspects and principles of confidentiality and some of the implications of these principles for computer-based storage and retrieval systems for statistical purposes. The remarks will have special relevance to open retrieval systems, that is, retrieval systems in which customers for information retrieval are the general public, or perhaps specified agencies or groups or individuals, and these customers can retrieve any desired statistics from the confidential records in the files subject to a review to insure that the output conforms to prescribed rules designed to avoid disclosure of individual information. These rules may be concerned with the minimum number of cases on which an individual statistics or frequency count is based or with other aspects, as is discussed later. The access to the data may be restricted to certain authorized types of data through control passwords or keys.
Reduction of arsenite-enhanced ultraviolet radiation-induced DNA damage by supplemental zinc

Arsenic is a recognized human carcinogen and there is evidence that arsenic augments the carcinogenicity of DNA damaging agents such as ultraviolet radiation (UVR) thereby acting as a co-carcinogen. Inhibition of DNA repair is one proposed mechanism to account for the co-carcinogenic actions of arsenic. We and others find that arsenite interferes with the function of certain zinc finger DNA repair proteins. Furthermore, we reported that zinc reverses the effects of arsenite in cultured cells and a DNA repair target protein, poly (ADP-ribose) polymerase-1. In order to determine whether zinc ameliorates the effects of arsenite on UVR-induced DNA damage in human keratinocytes and in an in vivo model, normal human epidermal keratinocytes and SKH-1 hairless mice were exposed to arsenite, zinc or both before solar-simulated (ss) UVR exposure. Poly (ADP-ribose) polymerase activity, DNA damage and mutation frequencies at the Hprt locus were measured in each treatment group in normal human keratinocytes. DNA damage was assessed in vivo by immunohistochemical staining of skin sections isolated from SKH-1 hairless mice. Cell-based findings demonstrate that ssUVR-induced DNA damage and mutagenesis are enhanced by arsenite, and supplemental zinc partially reverses the arsenite effect. In vivo studies confirm that zinc supplementation decreases arsenite-enhanced DNA damage in response to ssUVR exposure. From these data we can conclude that zinc offsets the impact of arsenic on ssUVR-stimulated DNA damage in cells and in vivo suggesting that zinc supplementation may provide a strategy to improve DNA repair capacity in arsenic exposed human populations.
Nonlinear Inverse and Predictive End Point Trajectory Control of Flexible Macro-Micro Manipulators

This paper presents a new approach to end-point trajectory control of flexible macro-micro manipulator based on nonlinear inversion and predictive control techniques. In this approach, precise control of the end-effector trajectory is accomplished by the inverse controller of the rigid micro manipulator, and the predictive controller steers the end point of the flexible macro manipulator with limited elastic oscillation. The predictive control law is obtained by minimizing a quadratic function of the tip tracking error, the elastic deflection, and the input torque of the flexible macro manipulator. The feedback parameters of the predictive controller are chosen such that zero dynamics are asymptotically stable. The combination of the inverse and the predictive controllers accomplishes precise end-effector trajectory tracking and elastic mode stabilization. These results are applied to a planar macro-micro manipulator system consisting of one flexible link and two micro rigid links. Simulation results are presented to show that in the closed-loop system time varying end point trajectory control and elastic mode stabilization are accomplished.
Synthesis of 9-(2-Hydroxyethoxymethyl)guanine (Acyclovir) from Guanosine

Abstract A convenient synthesis of 9-(2-hydroxyethoxymethyl)guanine (acyclovir) from guanosine by chemical transpurination was developed. The isomerization of the 7-isomer to the desired 9-isomer and the purification of the 9-isomer was achieved simply by concentration, heating and further crystallization.
Solution to beam vibrations problems with mixed response-excitation input information.

Vibration problems are considered in which one of the exciting forces is unknown but one of the response motions is known. Although the paper uses beam vibrations as a vehicle for illustrating the method of analysis, the method is valid for any remote coupled system. The basic method of solution involves recasting the equations of motion into a form in which the unknown exciting force does not appear and in which the known response motion appears as an exciting force. Since the coefficient matrices of these reduced equations are not symmetric, the usual methods of uncoupling equations are not applicable. After the equations are transformed to new coordinates based upon the eigenvectors of the reduced equations, they are uncoupled through the use of the eigenvectors of a related set of equations, called the adjoint equations. The uncoupled equations are easily solved by conventional methods.
Rank-down method for automatic lens design

A new automatic lens design method using singular value decomposition (SVD) is proposed. This method enables the designer to reflect his own intention in optimization via the Rank Down Constant introduced in this paper. This characteristic also makes it possible to accelerate the optimization. An example showing the high performance of this method is demonsirated. Some useful applications of S. V. D. are also proposed. 1 .
The synthesis of cyclobutanol-containing dipeptide analogues

The dipeptide analogue methyl trans-2-[(t-butoxycarbonyl)amino]-trans-3-hydroxycyclobutanecarboxylate (5a) and its cis,cis-isomer (5b) have been synthesized, and each has been incorporated into a longer peptide sequence.