cssi/SciSciGPT-SciSciNet huggingface dataset:
Achieving the Capacity of the $N$ -Relay Gaussian Diamond Network Within log $N$ Bits

We consider the $N$ -relay Gaussian diamond network where a source node communicates to a destination node via $N$ parallel relays through a cascade of a Gaussian broadcast (BC) and a multiple access (MAC) channel. Introduced in 2000 by Schein and Gallager, the capacity of this relay network is unknown in general. The best currently available capacity approximation, independent of the coefficients and the SNRs of the constituent channels, is within an additive gap of $1.3 N$ bits, which follows from the recent capacity approximations for general Gaussian relay networks with arbitrary topology. In this paper, we approximate the capacity of this network within 2 log $N$ bits. We show that two strategies can be used to achieve the information-theoretic cut-set upper bound on the capacity of the network up to an additive gap of $O(\log N)$ bits, independent of the channel configurations and the SNRs. The first of these strategies is simple partial decode-and-forward. Here, the source node uses a superposition codebook to broadcast independent messages to the relays at appropriately chosen rates; each relay decodes its intended message and then forwards it to the destination over the MAC channel. A similar performance can be also achieved with compress-and-forward type strategies (such as quantize-map-and-forward and noisy network coding) that provide the $1.3 N$ -bit approximation for general Gaussian networks, but only if the relays quantize their observed signals at a resolution inversely proportional to the number of relay nodes $N$ . This suggests that the rule-of-thumb to quantize the received signals at the noise level in the current literature can be highly suboptimal.
Bounding Fastest Mixing

In a recent work, Boyd, Diaconis and Xiao introduced a semidefinite programming approach for computing the fastest mixing Markov chain on a graph of allowed transitions, given a target stationary distribution. In this paper, we show that standard mixing time analysis techniques---variational characterizations, conductance, canonical paths---can be used to give simple, nontrivial lower and upper bounds on the fastest mixing time. To test the applicability of this idea, we consider several detailed examples including the Glauber dynamics of the Ising model.
Diels–Alder Reactions of β-Acylacrylic Acids

The Diels–Alder reaction of β-acylacrylic acids with dienes gave good yields and good regio- or stereoselectivity of the corresponding cycloaddition products with the use of Lewis acids.
Malleable coding with fixed segment reuse

In cloud computing, storage area networks, and remote backup storage, stored data is modified with updates from new versions. It is desirable for the data to not only be compressed but to also be easily modified during updates, since representing information and modifying the representation are both expensive. A malleable coding scheme considers both compression efficiency and ease of alteration, promoting codeword reuse. We examine the trade-off between compression efficiency and malleability cost—the difficulty of synchronizing compressed versions—measured as the length of a reused prefix portion. Through a coding theorem, the region of achievable rates and malleability is expressed as a single-letter optimization. Relationships to common information problems are also described.
X-Ray Emission from Clusters of Galaxies

1. Introduction 2. Optical observations 3. Radio observations 4. X-ray observations 5. Theoretical progress 6. Prospects for the future and AXAF References.
Tumor-Derived Hyaluronidase: A Diagnostic Urine Marker for High-Grade Bladder Cancer

The detection of high-grade bladder tumors prior to invasion is crucial for a good prognosis. We recently found that the levels of hyaluronic acid (HA), a glycosaminoglycan, are elevated in the urine of bladder cancer patients, and small angiogenic HA fragments are present in the urine of high-grade bladder cancer patients. Hyaluronidase is an enzyme that degrades HA into small angiogenic fragments. We compared the urinary hyaluronidase levels of normal individuals and patients with bladder cancer or other genitourinary conditions, using a substrate (HA)-gel technique and an ELISA-like assay. Among the 139 specimens analyzed, the urinary hyaluronidase levels in patients with G2/G3 tumors (33.4 +/- 4.5 milliunits/mg protein) are 5-8-fold higher than those in normal individuals (4.2 +/- 1.2 milliunits/mg protein) and those in patients with G1 tumors (6.5 +/- 1.7 milliunits/mg protein) or other genitourinary conditions (7.4 +/- 1.4 milliunits/mg protein; P < 0.001). Urinary hyaluronidase measurement shows a sensitivity of 100% and a specificity of 88.8% to detect high-grade bladder (G2/G3) tumors. Thus urinary hyaluronidase measurement is a simple, noninvasive yet highly specific and sensitive method for high-grade bladder cancer detection. The increase in urinary hyaluronidase levels is due to the secretion of a tumor-associated hyaluronidase into the urine because the hyaluronidase levels in G2/G3 tumor tissues are also higher (6-7-fold) than those in normal bladder and G1 tumor tissues (P < 0.001). The bladder tumor-associated hyaluronidase activity is distinct from other hyaluronidases, has a pH optimum of 4.3, and is attributed to two proteins with molecular masses of 65 kD (p65) and 55 kD (p55).
Radiative interactions in nonequilibrium flows

The influence of vibrational and chemical nonequilibrium upon infrared radiative energy transfer in nonisothermal gases is investigated. Essential information is provided on rate equations, relaxation times, transfer equations, band absorption, and radiative flux equations. The methodology developed is applied to three specific cases. These are, absorbing-emitting species between isothermal parallel plates, radiating gases in the earth's atmosphere, and supersonic flow of premixed hydrogen and air in an expanding nozzle. The results obtained for different cases reveal that the extent of radiative interactions is reduced significantly under nonequilibrium conditions. The method developed can be easily extended to investigate radiative interactions in complex nonequilibrium flows.
Theory for the polarization of the four cosmic OH 18-cm lines

Abstract The results of a theoretical study of the states of polarization in an OH maser amplifier are used to predict the anomalous polarization of the four cosmic OH 18-cm lines.
Monte Carlo simulation of magnetization reversal via domain-wall motion in Fe sesquilayers on W(110)

Iron sesquilayers are ultrathin films with coverages between one and two atomic mono-layers. They consist of an almost defect-free monolayer with compact islands of a second atomic layer on top. This variation of the film thickness results in a strong interaction between domain walls and the island structure. It makes these systems an ideal laboratory to study the dynamics of domain walls driven by weak external fields. We present computer simulations which provide insight into the role of the thermally activated nucleation processes by which a driven domain wall overcomes the obstacles created by the islands.
Trade-Policy Issues and Policy Options for Japan and the United States: Introduction and Overview

This symposium includes papers that analyse a number of issues that are likely to play a key role in the Doha Development Agenda (DDA) negotiations. These issues are analysed from the perspective of US-Japanese economic relations. In these papers, the economic effects of the WTO negotiating options available to both countries are explored. A final paper examines the important issues raised by the free trade agreements (FTAs) that have or will soon be negotiated by the United States and Japan. Brief summaries of the papers are provided. With all the advantages that have accrued to Japan from the multilateral trading system, it is not surprising that for many years Japan, alone among the world's major economies, stayed aloof from regional trading arrangements. The very past success of the multilateral trading system has made further progress at this level far more complex and has pushed many countries, Japan included, to look to new and deeper regional trading agreements as a more productive path. But it should not be forgotten that while FTAs may be easier to conclude, their benefits are modest compared with what can be gained from a successful Doha Round, and the costs from new distortions imposed on regional trade can be very significant for some of the world's poorer economies. Every good reason remains for Japan to continue to wish to be a pillar of the WTO and of the new Doha Round.
A microsimulated model of inventories in interfirm competition

Abstract Producers' management of inventories of finished goods are studied with a computer simulation that depicts the interactions of a group of firms with their customers. Customers give orders that have a random component to their current customary suppliers, and will attempt to switch to another firm if stockouts cause bad service. The firms are shown experimenting to find rules of inventory management that avoid loss of customers, yet incur low costs. Average inventories and costs under the rules that firms arrive at, rise non-linearly with the variance of customer orders. The simulated firms respond to higher interest rates by substantial cuts in average inventories held. The costs firms incur when changing the level of production also affects the rule that firms select. Unless firms are able to take advantage of each others' experience, wide variation in behavior among firms is likely under such a scenario.
The (In)stability of Planetary Systems

We present results of numerical simulations that examine the dynamical stability of known planetary systems, a star with two or more planets. First we vary the initial conditions of each system on the basis of observational data. We then determine regions of phase space that produce stable planetary configurations. For each system we perform 1000 ~ 106 yr integrations. We examine υ And, HD 83443, GJ 876, HD 82943, 47 UMa, HD 168443, and the solar system. We find that the resonant systems, two planets in a first-order mean motion resonance (HD 82943 and GJ 876) have very narrow zones of stability. The interacting systems, not in first-order resonance, but able to perturb each other (υ And, 47 UMa, and the solar system), have broad stable regions. The separated systems, two planets beyond 10 : 1 resonance (we examine only HD 83443 and HD 168443) are fully stable. We find that the best fits to the interacting and resonant systems place them very close to unstable regions. The boundary in phase space between stability and instability depends strongly on the eccentricities and (if applicable) the proximity of the system to perfect resonance. Furthermore, we also find that the longitudes of periastron circulate in chaotic systems but librate in regular systems. In addition to 106 yr integrations, we also examined stability on ~108 yr timescales. For each system we ran ~10 long-term simulations, and find that the Keplerian fits to these systems all contain configurations that are regular on this timescale.
Targeted Agricultural Export Subsidies and Social Welfare

Global export subsidies are known to be welfare reducing. This paper demonstrates that a small targeted subsidy can increase the welfare of the subsidizing country by exploiting differences in excess demand elasticities. Targeted export subsidies can also increase the subsidizing country's welfare by exploiting transportation cost differences, excess supply elasticities of competitors, or excess demand elasticities of markets supplied by competitors when markets are shared. An empirical model of the world wheat market illustrates the theoretical conclusions. An optimal targeted subsidy scheme causes a small increase in U.S. welfare but with major disruptions in world trade flows.
Testing lorenz curves with non-simple random samples

Simple random sampling has been assumed in most statistical inference procedures developed to test Lorenz dominance and other partial ordering conditions. This note, using the Bahadur representation, derives the (asymptotic) covariance structures of the Lorenz and generalized Lorenz ordinates for stratified, cluster and multistage samples. The comparison of these covariance structures illustrates the necessity of taking the sampling method into account in inference testing.
Characteristics of assaultive psychiatric inpatients: Updated review of findings, 1995-2000:

The present paper reviewed the studies of the characteristics of assaultive psychiatric inpatients from 1994 to the present. These studies partially confirmed earlier findings that assaultive patients are older persons with a diagnosis of active psychosis or other neurological abnormality and histories of violence toward others and substance-use disorder. However, the recent studies also document the profile of a second group of assaultive patients: younger females with personality disorders and histories of violence toward others, substance-use disorder, and personal victimization. Since there is a paucity of published empirical research on Alzheimer's and dementia patients for this topic, the implications from the present findings for long-term care and clinical intervention are examined.
A manifold calculus approach to link maps and the linking number

We study the space of link maps Link(P1,...Pk;N), which is the space of maps P1 ` � � � ` Pk → N such that the images of the Pi are pairwise disjoint. We apply the manifold calculus of functors developed by Goodwillie and Weiss to study the difference between it and its linear and quadratic approximations. We identify an appropriate generalization of the linking number as the geometric object which measures the difference between the space of link maps and its linear approximation. Our analysis of the difference between link maps and its quadratic approximation connects with recent work of the author, and is used to show that the Borromean rings are linked.
A photo-digital mass storage system

The photo-digital mass storage system does not impinge upon present day direct-access storage devices. Rather, it complements them and becomes another member in a hierarchy of files, each with its own specific capabilities and restrictions.
Cross-effects of fundamental state variables

This research is concerned with the transmission of shocks among fundamental state variables such as the stance of monetary policy, risk premia, and real output, as well as the SP Pesaran and Shin 1998), a method that is particularly well-suited to examine these interrelations because it does not impose a priori restrictions as to the relative importance each of these variables may play in the transmission process. The results identify important cross-effects among these factors as measured by their responses to unanticipated changes to each of the variables within the system.
A gold-catalyzed [4+3]-cycloaddition of functionalized dioxines

Abstract Treatment of 5-silyloxydioxins with 5 mol % AuCl3/AgSbF6 in the presence of cyclopentadiene or furan results in the rapid formation of [4+3]-cycloadducts at room temperature.
RG flows in the D-series of minimal CFTs

Using results of the thermodynamic Bethe ansatz approach and conformal perturbation theory we argue that the φ1,3 perturbation of a unitary minimal (1+1)-dimensional conformal field theory (CFT) in the D-series of modular invariant partition functions induces a renormalization group (RG) flow to the next-lower model in the D-series. An exception is the first model in the series, the three-state Potts CFT, which under the Z2-even φ1,3-perturbation flows to the tricritical Ising CFT, the second model in the A-series. We present arguments that in the A-series flow corresponding to this exceptional case, interpolating between the tetracritical and the tricritical Ising CFT, the IR fixed points is approached from “ exactly the opposite direction” Our results indicate how (most of) the relevant conformal fields evolve from the UV to the IR CFT.
Geometric Quantization and Two Dimensional QCD

In this article, we will discuss geometric quantization of two dimensional Quantum Chromodynamics with fermionic or bosonic matter fields. We identify the respective large-Nc phase spaces as the infinite dimensional Grassmannian and the infinite dimensional Disc. The Hamiltonians are quadratic functions, and the resulting equations of motion for these classical systems are nonlinear. In [33], it was shown that the linearization of the equations of motion for the Grassmannian gave the 't Hooft equation. We will see that the linearization in the bosonic case leads to the scalar analog of the 't Hooft equation found in [36].
2,4,6‐trichloropyrimidine. Reaction with anilines

The reaction of 2,4,6-trichloropyrimidine 1 with a variety of 4-substituted anilines 2 has been investigated. Monosubstitution occurs readily for all anilines except those containing strongly electron-withdrawing groups. The yields of the isomeric products 3 and 4 parallel the Hammet constants of the ring substituents. The main product when ethanol was used as the solvent was the 4-substituted-2,6-dichloropyrimidine 3. Spectral and X-ray data confirmed this assignment. However, a solvent dependence on the 3:4 ratio was demonstrated. In some cases, excess aniline under forcing conditions led to 2,4-disubstituted products.
Preparation of a fluorinated shikimic acid

Abstract The reaction of dialkylaminosulfur trifluoride with shikimic acid (1) gives a single isomer of a product 2 in which two hydroxy groups have been replaced by fluorine.
Radiochemical measurements of tritium during heavy water electrolysis at palladium cathodes in closed cells

Abstract Closed cell electrolysis of heavy water at palladium cathodes was maintained for 100 days by the catalytic recombination of evolved gases. Closed cell operation eliminated several experimental complications including electrolytic isotope separation effects. This allowed for the detection of tritium accumulation at a level two orders of magnitude below that cited by Fleischmann, Pons, and Hawkins as evidence for cold fusion. Closed cell electrolysis of alkaline heavy water was performed in six cells with several variations in palladium cathode pretreatment, anode type, cell vessel material, electrolyte preparation, and current density. In each case, light water control cells were operated under otherwise identical conditions. Under conditions close to those under which cold fusion phenomena have been reported, radiochemical measurements have indicated no accumulation of tritium.
Hierarchical Star Formation in the Spiral Galaxy NGC 628

The distributions of size and luminosity for star-forming regions in the nearby spiral galaxy NGC 628 are studied over a wide range of scales using progressively blurred versions of an image from the Hubble Space Telescope Advanced Camera for Surveys. Four optical filters are considered for the central region, including H?. Two filters are used for an outer region. The features in each blurred image are counted and measured using SExtractor. The cumulative size distribution is found to be a power law in all passbands, with a slope of approximately -1.5 over 1.8 orders of magnitude. The luminosity distribution is approximately a power law as well, with a slope of approximately -1 for logarithmic intervals of luminosity. The results suggest a scale-free nature for stellar aggregates in a galaxy disk. Fractal models of thin disks reproduce the projected size distribution and suggest a projected mass distribution slope of approximately -0.5 for these extended regions. This mass slope converts to the observed luminosity slope if we account for luminosity evolution and longer lifetimes in larger regions.
Limits to List Decoding Reed&#8211;Solomon Codes

In this paper, we prove the following two results that expose some combinatorial limitations to list decoding Reed-Solomon codes. 1) Given n distinct elements alpha1,...,alphan from a field F, and n subsets S1,...,Sn of F, each of size at most l, the list decoding algorithm of Guruswami and Sudan can in polynomial time output all polynomials p of degree at most k that satisfy p(alphai)isinSi for every i, as long as l 0 (agreement of k is trivial to achieve). Such a bound was known earlier only for a nonexplicit center. Finding explicit bad list decoding configurations is of significant interest-for example, the best known rate versus distance tradeoff, due to Xing, is based on a bad list decoding configuration for algebraic-geometric codes, which is unfortunately not explicitly known
Asymptotic linearity of the mapping class group and a homological version of the Nielsen–Thurston classification

We study the action of the mapping class group on the integral homology of finite covers of a topological surface. We use the homological representation of the mapping class to construct a faithful infinite-dimensional representation of the mapping class group. We show that this representation detects the Nielsen–Thurston classification of each mapping class. We then discuss some examples that occur in the theory of braid groups and develop an analogous theory for automorphisms of free groups. We close with some open problems.
Acoustic Emissions Applications on the Nasa Space Station

The space station is an internally pressurized container carrying inside it everything necessary to support human life in space. Since the shell of the space station contains numerous penetrations it will always be susceptible to seal failure, and when in orbit it will also be exposed to impacts from meteoroids and debris. Although designed to minimize the effects of impacts, damage which breaches the shell threatens the lives of the astronauts. Even small penetrations may require an unacceptable amount of time and effort to locate if a manual scan is necessary. Monitoring under these conditions is best done with acoustic emission (AE), which can be configured as a continuous, remote, and operator-independent monitoring system capable of detecting and locating large and small damage sources.
Diastereoselective synthesis of multisubstituted thiacyclohexanes via cation–olefin cyclizations

Abstract Thiacyclohexane derivatives were synthesized in high yields with excellent diastereoselectivity via an indium trichloride-mediated cationic cyclization.
Optimal trading ratios for pollution permit markets

Abstract We demonstrate a novel method for improving the efficiency of pollution permit markets by optimizing the exchange of emissions through trade. Under full-information, it is optimal for emissions to exchange according to the ratio of marginal damages. Under asymmetric information, we derive necessary conditions for the marginal damage trading ratios to be optimal, illustrate that the marginal damage trading ratios are generally not optimal, and show how to improve efficiency using optimal trading ratios. We calculate the optimal trading ratios for a global carbon market. The gains from using optimal trading ratios rather than marginal damage trading ratios range from substantial to trivial, which suggests the need for careful consideration of asymmetric information when designing permit markets.
α-amino carbanions. A competition study to assess relative acidities in various formamidines

Abstract Various N-groups on formamidines have been examined to see which enhance proton removal adjacent to nitrogen.
Obesity, Weight Gain, and Risk of Biochemical Failure Among Prostate Cancer Patients Following Prostatectomy

Purpose: Several lines of evidence suggest that diet and weight gain may be important environmental factors implicated in prostate carcinogenesis, especially in tumor progression. The purpose of this study was to evaluate obesity at different ages in a well-characterized cohort of prostate cancer patients treated with prostatectomy and to develop a prognostic model that incorporates body mass index (BMI) as a measure of obesity. Experimental Design: We carried out a prospective study of 526 patients registered at the M.D. Anderson Cancer Center from 1992 to 2001. Kaplan-Meier and Cox proportional hazard analyses were done. Results: During an average follow-up of 54 months, 97 (18%) post-prostatectomy patients experienced biochemical failure. Patients who were obese (BMI ≥ 30 kg/m 2 ) at diagnosis had a higher rate of biochemical failure than nonobese men ( P = 0.07). Those obese at 40 years had an even greater rate of biochemical failure ( P = 0.001). Higher BMI at diagnosis [hazard ratio (HR), 1.07; P = 0.01] and Gleason score = 7(4 + 3) and ≥8 (HR, 3.9; P = 0.03 and HR, 10.0; P ≤ 0.001, respectively) remained significant independent predictors of biochemical failure in multivariate analysis. Men who gained weight at the greatest rate (>1.5 kg/y) between 25 years and diagnosis progressed significantly sooner (mean time, 17 months) than those who exhibited a slower weight gain (mean time, 39 months; P trend = 0.005). The inclusion of obesity to the clinical nomogram improved performance. Conclusions: Our findings validate the importance for a role of obesity in prostate cancer progression and suggest a link to the biological basis of prostate cancer progression that can be therapeutically exploited.
Quantum Spins and Quantum Links: The D-Theory Approach to Field Theory

Abstract A new non-perturbative approach to quantum field theory is proposed. Instead of performing a path integral over configurations of classical fields, D-theory works with discrete quantized variables. Classical spin fields are replaced by quantum spins, and classical gauge fields are replaced by quantum links. The classical fields of a d -dimensional quantum field theory reappear as low-energy effective degrees of freedom of the discrete variables, provided the ( d +1)-dimensional D-theory is massless. When the extent of the extra Euclidean dimension becomes small in units of the correlation length, an ordinary d -dimensional quantum field theory emerges by dimensional reduction. The D-theory formulation of some spin models and gauge theories is constructed explicitly. In particular, QCD emerges as a quantum link model.
Formation of six- versus five-membered cyclic sulfones by C–H insertion

Selectivity of six- vs. five- membered ring formation in C-H insertion on alkylsulfonyl diazoacetates is sensitive to the substrate structure and catalyst used.
Oxidative carbon-carbon bond formation via silyl bis-enol ethers: controlled cross-coupling for the synthesis of quaternary centers.

Unsymmetrical silyl bis-enol ethers have been developed as effective substrates for synthesizing quaternary centers from tetralone derivatives through oxidative carbon−carbon bond formation. The derived products are shown to be highly versatile intermediates that may be used to generate diverse structures such as cyclopentenones, 2H-pyrroles, and spirocyclic pyrrolidines.
Exploring Alternative Measures of Welfare in the Absence of Expenditure Data

We consider an asset-based alternative to the standard use of expenditures in defining well-being and poverty. Our motivation is to see if there exist simpler and less demanding ways to collect data to measure economic welfare and rank households. This is particularly important in poor regions where there is limited capacity to collect consumption, expenditure and price data. We evaluate an index derived from a factor analysis on household assets using multipurpose surveys from several countries. We find that the asset index is a valid predictor of a crucial manifestation of poverty—child health and nutrition. Indicators of relative measurement error show that the asset index is measured as a proxy for long-term wealth with less error than expenditures. Analysts may thus prefer to use the asset index as an explanatory variable or as a means of mapping economic welfare to other living standards and capabilities such as health and nutrition.
The Higgs Bridge

The particle recently discovered at the Large Hadron Collider near Geneva is almost certainly a Higgs boson, the long-sought completion of the Standard Model of particle physics. But this discovery, an achievement by more than 6000 scientists (including students), is actually much more than a mere capstone of the Standard Model. It instead represents a bridge from the Standard Model to exciting discoveries of the future, at higher energies or in other experiments, and to the properties of matter at very low temperatures. The mere existence of a particle with zero spin implies a need for new physics, with the most likely candidate being supersymmetry, which requires that every known particle has a superpartner yet to be discovered. And phenomena similar to the Higgs are seen in superconducting metals and superfluid gases at low temperatures, which extend down to a millionth or even a billionth of a degree Kelvin. So the discovery of a Higgs boson has a central place in our attempts both to achieve a true understanding of Nature and to harness Nature in practical applications.
Distinctive Meta-Directing Group Effect for Iridium-Catalyzed 1,1-Diarylalkene Enantioselective Hydrogenation

An iridium-catalyzed asymmetric hydrogenation of 1,1-diarylkenes is described. Employing a novel, modular phosphoramidite ligand, PhosPrOx, in this transformation affords biologically relevant 1,1-diarylmethine products in good enantiomeric ratios (96.5:3.5 to 71:29). We propose that a meta-directing group, 3,5-dimethoxyphenyl, is responsible for the observed enantioselection, the highest reported, to date, for iridium-catalyzed hydrogenation of 1,1-diarylalkenes lacking ortho-directing groups.
Improving the performance guarantee for approximate graph coloring

The performance guarantee of a graph coloring algorithm is the worst case ratio between the number of colors it uses on the input graph and the chromauc number of this graph. The previous best known polynomial-time algorithm had a performance guarantee O(n/logn) for graphs on n vertices. This result stood unchallenged for eight years. This paper presents an efficient algorithm with performance guarantee of O(n(loglog n)2/(logn)2).
An Improved Strichartz Estimate for Systems with Divergence Free Data

Using the div-curl inequalities of Bourgain and Brezis [1] and van Schaftingen [9], we prove an improved Strichartz estimate for systems of inhomogeneous wave and Schrodinger equations, for which the inhomogeneity is a divergence-free vector field at each given time. The novelty of the result is that one can allow norms of the inhomogeneity in the right hand side of the estimate.
Ground-state wave-function “representation”☆

Abstract Starting from a general quantum mechanical system: H= − 1 2 ∂ 2 ∂x 2 +U(x) , we show how its vacuum-vacuum correlation functions can be derived from a supersymmetric hamiltonian with superpotential V=−ln Ψ0, where Ψ0 is the ground-state wave function of H.
Taxes, efficiency, and redistribution: Discriminatory taxation of villages in Ottoman Palestine, Southern Syria, and Transjordan in the sixteenth century☆

Abstract Governments can tax productive activities with either uniform or discriminatory rates among taxpayers. Although discriminatory rates can cause productive inefficiency and require high cost of administration, they can be preferred because of their advantage in distributional flexibility. This paper studies the discriminatory taxation of production in the Fertile Crescent. Using information from the Ottoman tax registers, it examines the basis, distortionary effects, and distributional consequences of discriminatory rates quantitatively. The results challenge widely held beliefs about the basis for discriminatory rates in this region and the Ottoman government’s motivation in adapting systems of taxation in newly conquered lands.
Two-dimensional mixed convection along a flat plate

For a horizontal plate, the axial pressure gradient induced by the buoyancy force is 0(Gr/Re{sup 5/2}). Numerous solutions have been developed by considering the free-convection effect as a perturbation quantity. Again, forced convection exists as a limit for small Gr/Re{sup 5/2} and the free-convection limit can be reached as the parameter approaches infinity. The critical difference between the flow over a horizontal plate and a vertical plate has been pointed out by Cheng and his co-workers. The buoyancy force normal to the plate can induce a vortex instability. The governing parameter for the development of this instability is Gr/Re{sup 3/2}. In this paper, the authors re-examine this problem. For a vertical plate, they show that two limits can exists for {xi} {yields} {infinity}, depending on whether Re {yields} O, or Gr {yields} {infinity}. The mixed-convection, boundary-layer solution is valid for the limit Re {yields} {theta}. The solution for the limit, Re {yields} O, is the free-convection solution, but the forced-convection effect cannot be obtained by solving mixed-convection, boundary-layer equations alone. Also, they demonstrate by order-of-magnitude arguments that Cr/Re{sup 5/2} is not the governing parameter for mixed convection along a horizontal plate. For an inclined plate, as long as no vortexmore » instability develops, Gr/Re{sup 2} is the sole parameter for mixed-convection flows. This conclusion is confirmed by recent measurements (24). The physical model of the analysis is kept simple in order to point out the important physics; thus, the forced flow is assumed along the same direction as the free convection (assisting flow), and the value of the Prandtl number is set to one (Pr = 1).« less
Delay-based network utility maximization

It is well known that max-weight policies based on a queue backlog index can be used to stabilize stochastic networks, and that similar stability results hold if a delay index is used. Using Lyapunov optimization, we extend this analysis to design a utility maximizing algorithm that uses explicit delay information from the head-of-line packet at each user. The resulting policy is shown to ensure deterministic worst-case delay guarantees and to yield a throughput utility that differs from the optimally fair value by an amount that is inversely proportional to the delay guarantee. Our results hold for a general class of 1-hop networks, including packet switches and multiuser wireless systems with time-varying reliability .
Numerical results for spin glass ground states on Bethe lattices:Gaussian bonds

The average ground state energies for spin glasses on Bethe lattices of connectivities r = 3,...,15 are studied numerically for a Gaussian bond distribution. The Extremal Optimization heuristic is employed which provides high-quality approximations to ground states. The energies obtained from extrapolation to the thermodynamic limit smoothly approach the ground-state energy of the Sherrington-Kirkpatrick model for r ↦ ∞. Consistently for all values of r in this study, finite-size corrections are found to decay approximately with ~N-4/5. The possibility of ~N-2/3 corrections, found previously for Bethe lattices with a bimodal ± J bond distribution and also for the Sherrington-Kirkpatrick model, are constrained to the additional assumption of very specific higher-order terms. Instance-to-instance fluctuations in the ground state energy appear to be asymmetric up to the limit of the accuracy of our heuristic. The data analysis provides insights into the origin of trivial fluctuations when using continuous bonds and/or sparse networks.
Improved understanding of physical defect mechanisms using fault simulation

Failure mechanisms in highly integrated designs are becoming more subtle, making them difficult to locate and understand. Successful analysis requires the precise location of the anomaly in three dimensions, prior to physical analysis, when strip and inspect techniques do not yield a failure mechanism. This paper presents a technique whereby simulations of hypothesized defects, in combination with I-V curves obtained by electrical microprobing, aid in locating physical defects. Given the exact location, techniques requiring that the physical and chemical sample integrity be maintained, such as TEM and AES, can be employed to give insight into the failure mechanism.
Localization of matter and cosmological constant on a brane in anti de Sitter space

Abstract We study two issues, the localization of various spin fields, and the problem of the cosmological constant on a brane in five-dimensional anti de Sitter space. We find that spin-zero fields are localized on a positive-tension brane. In addition to the localized zero-mode there is a continuous tower of states with no mass gap. Spin one-half and three-half states can be localized on a brane with “negative tension”. Their localization can be achieved on the positive-tension brane as well, if additional interactions are introduced. The necessary ingredient of the scenario with localized gravity is the relation between the bulk cosmological constant and the brane tension. In the absence of supersymmetry this implies fine-tuning between the parameters of the theory. To deal with this issue we introduce a four-form gauge field. This gives an additional arbitrary contribution to the bulk cosmological constant. As a result, the model gives rise to a continuous family of brane Universe solutions for generic values of the bulk cosmological constant and the brane tension. Among these solutions there is one with a zero four-dimensional cosmological constant.
Impact of mode of delivery on markers of perinatal hemodynamics in infants with hypoplastic left heart syndrome.

Objective To determine whether the mode of delivery of infants prenatally diagnosed with hypoplastic left heart syndrome (HLHS) affects markers of perinatal hemodynamics. Study design A retrospective review of patients diagnosed prenatally with HLHS and delivered within our institution was undertaken. Arterial blood gases, echocardiographic data, and markers of end organ function were compared based on route of delivery. Results A total of 79 infants with HLHS were enrolled between January 2002 and December 2008. The infants delivered by elective cesarian delivery (CD) had younger gestational age compared with those delivered by vaginal delivery (VD) or by urgent CD/operative VD. Those delivered by elective CD had lower pH and higher partial pressure of CO2 on arterial cord blood gas analysis. There were no differences in partial pressure of O2 and base deficit among the 3 study groups. One-minute and 5-minute Apgar scores, markers of end organ function, echocardiographic parameters, length of hospitalization, and survival to discharge were similar among the groups. Conclusions Overall, newborns with a prenatal diagnosis of HLHS transitioned well to extrauterine life without significant acidosis regardless of the mode of delivery. Delivery of newborns with HLHS by elective CD did not demonstrate any hemodynamic advantage over VD in our cohort of patients.
System Parameters for the Eclipsing B-Star Binary HD 42401

I present results from an optical spectroscopic investigation of the binary system HD 42401 (V1388 Ori; B2.5 IV-V + B3 V). A combined analysis of V-band photometry and radial velocities indicates that the system has an orbital period of 2.18706 ? 0.00005 days and an inclination of 755 ? 02. This solution yields masses and radii of M 1 = 7.42 ? 0.08 M ? and R 1 = 5.60 ? 0.04 R ? for the primary and M 2 = 5.16 ? 0.03 M ? and R 2 = 3.76 ? 0.03 R ? for the secondary. Based on the position of the two stars plotted on a theoretical Hertzsprung-Russell diagram, I find that the age of the system is 25 Myr and that both stars appear overluminous for their masses compared to single-star evolutionary tracks. A fit of the spectral energy distribution based on photometry from the literature yields a distance of 832 ? 89 pc to HD 42401.
Using wait-free synchronization in the design of distributed applications

Wait-free synchronization has been recognized in the literature as an effective concurrent programming technique. The concurrent programming community, however, has been slow to adopt this technique. This paper addresses the practical application of wait-free synchronization in the design of distributed applications. In this paper, we present an implementation of a server that uses wait-free synchronization. The resulting code is more easily seen to be fault tolerant. The performance analysis of the wait-free synchronization server outperformed a server that uses traditional locking techniques. This practical demonstration of the benefits of wait-free synchronization should help foster its adoption in the development of distributed applications.
Reidemeister torsion, the Alexander polynomial and U (1,1) Chern-Simons theory

Abstract We show that the U (1,1) (super) Chern-Simons theory is one-loop exact. This provides a direct proof of the relation between the Alexander polynomial and analytic and Reidemeister torsions. We then compute explicitly the torsions of Lens spaces and Seifert manifolds using surgery and the S and T matrices of the U (1,1) Wess-Zumino-Witten model recently determined, with complete agreement with known results. U (1,1) quantum field theories and the Alexander polynomial thus provide “toy” models with a non-trivial topological content, where all ideas put forward by Witten for SU (2) and the Jones polynomial can be explicitly checked, at finite k . Some simple but presumably generic aspects of non-compact groups, like the modified relation between Chern-Simons and Wess-Zumino-Witten theories, are also illustrated. We comment on the closely related case of GL (1,1).
Quantum interference with beamlike type-II spontaneous parametric down-conversion

We implement experimentally a method to generate photon-number-path and polarization entangled photon pairs using "beamlike" type-II spontaneous parametric down-conversion (SPDC), in which the signal-idler photon pairs are emitted as two separate circular beams with small emission angles rather than as two diverging cones
Finite element structural redesign by large admissible perturbations

Abstract In structural redesign, two structural states are involved: the baseline (known) state S1 with unacceptable performance, and the objective (unknown) state S2 with given performance specifications. The difference between the two states in design variables and performance may be as high as 100% or more depending on the scale of the structure and the design problem considered. A perturbation approach to redesign (PAR) is presented to relate any two structural states S1 and S2 that are modeled by the same finite element model but represented by different values of the design variables. General perturbation equations are derived expressing implicitly the natural frequencies, dynamic modes, static deflections, static stresses, Euler buckling loads and buckling modes of the objective state S2 in terms of its performance specifications, and only state S1 data and FEA results. Large admissible perturbations (LEAP) algorithms are implemented in code RESTRUCT to define the objective state S2 incrementally without trial and error by postprocessing FEA results of state S1 with no additional FEAs. Systematic numerical applications in redesign of a 10-element 48-d.o.f. beam, a 104-element 192-d.o.f. offshore tower, a 64-element, 216-d.o.f. plate, and a 144-element 896-d.o.f. cylindrical shell show the accuracy, efficiency, and potential of PAR to find an objective state that may differ 100% or more from the baseline design.
Expatriate adjustment: considerations for selection and training

Purpose – The purpose of this paper is to first, synthesize employee characteristics that have been shown to help expatriate adjustment into best practices that can aid in expatriate selection. Second, the authors aim to identify training design variables that can be implemented to not only increase learning and expatriate adjustment, but also to maximize the benefits of employee characteristics. Finally, the authors point out environmental factors that are often overlooked, but yet important influencing forces of expatriate adjustment. Design/methodology/approach – PsychINFO was searched using variations of the following terms: expatriate selection and expatriate training. For the selection criteria, the authors selected articles in which cross-cultural adjustment, expatriate performance, or learning was the dependent variable. Reference sections of these articles were then cross-referenced for additional support. Authors then double-coded every article independently to record variables, study methodolog...
High-resolution, coupled thermosphere–ionosphere models for space weather applications

Abstract Current first-principles global models of the coupled thermosphere–ionosphere (T–I) system use grids that are too coarse to simulate the mesoscale and small-scale structures that occur in this complex system. These small-scale and mesoscale structures have a great effect on global-scale neutral and plasma distributions and have important consequences for daily space weather. In this paper, we present a new first-principles, high-resolution, T–I nested grid (TING) polar cap model that incorporates multiple nesting levels and two-way interaction. The TING model simulation of the electron densities and temperatures demonstrates the importance of high spatial resolution. It is found that both the mid-latitude electron density trough and its associated dawn electron temperature peak are more pronounced and structured in the nested grid than in the coarse grid. Using the TING model to simulate ionospheric F 2 region electron density variations with geomagnetic activity and universal time (UT) is also discussed.
Bricks and mortar self-assembly of nanoparticles

Abstract The use of nanoparticles and polymers bearing complementary recognition elements provides a versatile method for the formation of nanoparticle aggregates. This assembly process is highly dependent upon the primary and secondary recognition elements attached to the polymer and nanoparticle; we have observed variations in aggregate morphology that are directly correlated to supramolecular events at the colloid–polymer interface.
Turbulent boundary layers at very large Reynolds numbers

Andrei Nikolaevich Kolmogorov firmly believed that in the absence of a rigorous self-contained theory of turbulent fluids and gases one must use hypotheses obtained by processing experimental data. This paper begins with a discussion of the hypothesis of complete self-similarity used in the proof of the widely known (Reynolds-number independent) von Karman-Prandtl logarithmic law for the distribution of velocity in a turbulent shear flow. It is shown that this hypothesis has not been confirmed experimentally. Instead, a hypothesis of incomplete self-similarity is proposed which leads to a power-law dependence on the Reynolds number. It is shown that this law agrees well with experiments for the most important classes of turbulent shear flows (for flows in pipes and boundary layers).
Enantioselective Synthesis of 3,4-Chromanediones via Asymmetric Rearrangement of 3-Allyloxyflavones

Asymmetric scandium(III)-catalyzed rearrangement of 3-allyloxyflavones was utilized to prepare chiral, nonracemic 3,4-chromanediones in high yields and enantioselectivities. These synthetic intermediates have been further elaborated to novel heterocyclic frameworks including angular pyrazines and dihydropyrazines. The absolute configuration of rearrangement products was initially determined by a nonempirical analysis of circular dichroism (CD) using time-dependent density functional theory (TDDFT) calculations and verified by X-ray crystallography of a hydrazone derivative. Initial studies of the mechanism support an intramolecular rearrangement pathway that may proceed through a benzopyrylium intermediate.