cssi/SciSciGPT-SciSciNet huggingface dataset:
Antenna Selection for MIMO-OFDM Systems With Channel Estimation Error

We study space-time-frequency coded multiple-input-multiple-output (MIMO) orthogonal frequency-division multiplexed (OFDM) systems employing receiver antenna selection (AS), where training has been utilized to perform linear minimum mean square error (LMMSE)-based channel estimation. To minimize the mean square error (MSE) of this estimator, equispaced and equipowered training symbols are used, with the number of training symbols per OFDM symbol equal to the channel length. The maximum received signal power AS rule is proposed, which decouples the AS process from the channel estimation process. By upper bounding the pairwise error probability (PEP) expression, we show that the system with a channel-estimation error (CEE) still achieves maximum spatial and multipath diversity. The performance of the system for the special case of square unitary and orthogonal codes has been analyzed. For the case of orthogonal codes using constant modulus symbols, we also derive the exact bit-error-rate (BER) expression. The degradation in performance, due to the presence of the CEE, is captured by the loss-in-coding-gain (LCG) and loss-in-performance (LP) expressions. To minimize the loss due to the CEE, an optimal power-allocation scheme that distributes the total available power between training symbols and data symbols is defined. Compared with the perfect channel knowledge case, equal power training for the CEE case performs at least 3 dB worse, whereas optimal power training for the CEE case suffers a loss less than 3 dB always. Analytical and simulation results are presented to validate our analysis and results.
Ion‐Selective Electrodes for Measurements in Biological Fluids

The sections in this article are Zero-current Electrochemical Cells Incorporating Ion-selective Membranes Selectivity of Potentiometric Membrane Electrodes Glass Electrodes Solid-state Electrodes Liquid Membrane Electrodes Ion-exchangers Neutral Ionophores Charged Ionophores Gas-sensing Probes Ion-selective Electrode-based Biosensors
Interaction of a Stream of Dielectric Spheres in an Electric Field in a High Vacuum

The interaction of a stream of dielectric spheres in an electric field in a high vacuum is investigated both theoretically and experimentally. This investigation is motivated by an attempt to detect fractional electric charges which might exist in matter, namely, a search for isolated quarks in matter. The theoretical analysis is intended to pinpoint the basic interaction mechanism by which a stream of dielectric spheres becomes destabilized in an electric field. One important result of this analysis is a suggested method by which the destabilizing forces can be eliminated. The experiments performed are intended to study the behavior of a stream of uniform liquid drops in an electric field in a high vacuum. It is seen from these experiments that the deflections of any two drops in the stream with charges differing by one electronic charge is the same except for the effects of some destabilizing forces.
Stability of rank-3 Lazarsfeld-Mukai bundles on K3 surfaces

Given an ample line bundle L on a K3 surface S, we study the slope stability with respect to L of rank-3 Lazarsfeld-Mukai bundles associated with complete, base point free nets of type g^2_d on curves C in the linear system |L|. When d is large enough and C is general, we obtain a dimensional statement for the variety W^2_d(C). If the Brill-Noether number is negative, we prove that any g^2_d on any smooth, irreducible curve in |L| is contained in a g^r_e which is induced from a line bundle on S, thus answering a conjecture of Donagi and Morrison. Applications towards transversality of Brill-Noether loci and higher rank Brill-Noether theory are then discussed.
Mild and efficient formation of symmetric biaryls via Pd(II) catalysts and Cu(II) oxidants

Described herein is a mild and efficient palladium-catalyzed synthesis of symmetric biaryls from organostannanes. This methodology offers products rapidly in very high yields.
Total Synthesis of (+)‐Halichlorine: An Inhibitor of VCAM‐1 Expression

The diastereoselective addition of the highly functionalized organozinc compound 1 to the aldehyde 2 in the presence of the chiral amino alcohol 3 (-->4) is a key step in the first total synthesis of (+)-halichlorine. A series of protections/deprotections and a macrolaconization complete the synthesis. Halichlorine selectively inhibits the expression of the cell adhesion molecule VCAM-1. TBS=tert-butyldimethylsilyl.
Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model.

For the first time, a physics based computational model has been used to provide a direct description of the effects of the traveling wave tube (TWT) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion, gain and phase ripple, drive-induced oscillations, harmonic generation, intermodulation products, and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry of the high-power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept-amplitude and/or swept-frequency data. The fully three-dimensional (3-D) time-dependent, TWT interaction model using the electromagnetic code MAFIA is presented. This model is used to investigate assumptions made in conventional TWT black-box models used in communication system level simulations. To quantitatively demonstrate the effects these approximations have on digital signal performance predictions, including intersymbol interference, direct digital data input into the MAFIA model is compared to the system level analysis tool, SPW, which incorporates these approximations.
Extensions, Levi subgroups and character formulas ✩

Abstract This paper consists of three interconnected parts. Parts I, III study the relationship between the cohomology of a reductive group G and that of a Levi subgroup H. For example, we provide a sufficient condition, arising from Kazhdan–Lusztig theory, for a natural map Ext G • ( L , L ′ ) → Ext H • ( L H , L H ′ ) to be surjective, given irreducible G-modules L , L ′ and corresponding irreducible H-modules L H , L H ′ . In cohomological degree n = 1 , the map is always an isomorphism, under our hypothesis. These results were inspired by recent work of Hemmer [D. Hemmer, A row removal theorem for the Ext 1 quiver of symmetric groups and Schur algebras, Proc. Amer. Math. Soc. 133 (2) (2005) 403–414 (electronic)] for G = GL n , and both extend and improve upon the latter when our condition is met. Part II obtains results on Lusztig character formulas (LCFs) for reductive groups, obtaining new necessary and sufficient conditions for such formulas to hold. In the special case of G = GL n , these conditions can be recast in a striking way completely in terms of explicit representation theoretic properties of the symmetric group. This work on GL n improves upon [B. Parshall, L. Scott, Quantum Weyl reciprocity for cohomology, Proc. London Math. Soc. 90 (3) (2005) 655–688], which established only sufficient, rather than necessary and sufficient, conditions for the validity of the LCF in terms of the symmetric group.
Investigation of acoustical shielding by a wedge-shaped airframe

Experiments on a scale model of an advanced unconventional subsonic transport concept, the Blended Wing Body (BWB), have demonstrated significant shielding of inlet-radiated noise. A computational model of the shielding mechanism has been developed using a combination of boundary integral equation method (BIEM) and equivalent source method (ESM). The computation models the incident sound from a point source in a nacelle and determines the scattered sound field. In this way the sound fields with and without the airfoil can be estimated for comparison to experiment. An experimental test bed using a simplified wedge-shape airfoil and a broadband point noise source in a simulated nacelle has been developed for the purposes of verifying the analytical model and also to study the effect of engine nacelle placement on shielding. The experimental study is conducted in the Anechoic Noise Research Facility at NASA Langley Research Center. The analytic and experimental results are compared at 6300 and 8000 Hz. These frequencies correspond to approximately 150 Hz on the full scale aircraft. Comparison between the experimental and analytic results is quite good, not only for the noise scattering by the airframe, but also for the total sound pressure in the far field. Many of the details of the sound field that the analytic model predicts are seen or indicated in the experiment, within the spatial resolution limitations of the experiment. Changing nacelle location produces comparable changes in noise shielding contours evaluated analytically and experimentally. Future work in the project will be enhancement of the analytic model to extend the analysis to higher frequencies corresponding to the blade passage frequency of the high bypass ratio ducted fan engines that are expected to power the BWB.
La9RbIr4O24: A Rubidium-Containing Oxide with a New Structure Type

Single crystals of La9RbIr4O24, grown from a molten rubidium hydroxide flux, crystallize in the space group I4/m with lattice parameters a = 7.7422(3) A and c = 17.7979(11) A. The oxide forms in a new complex structure type.
Visual Object Recognition: Do We Know More Now Than We Did 20 Years Ago?

We review the progress made in the field of object recognition over the past two decades. Structural-description models, making their appearance in the early 1980s, inspired a wealth of empirical research. Moving to the 1990s, psychophysical evidence for view-based accounts of recognition challenged some of the fundamental assumptions of structural-description theories. The 1990s also saw increased interest in the neurophysiological study of high-level visual cortex, the results of which provide some constraints on how objects may be represented. By 2000, neuroimaging arose as a viable means for connecting neurons to behavior. One of the most striking fMRI results has been category selectivity, which provided further constraints for models of object recognition. Despite this progress, the field is still faced with the challenge of developing a comprehensive theory that integrates this ever-increasing body of results and explains how we perceive and recognize objects.
Real-time crowd control of existing interfaces

Crowdsourcing has been shown to be an effective approach for solving difficult problems, but current crowdsourcing systems suffer two main limitations: (i) tasks must be repackaged for proper display to crowd workers, which generally requires substantial one-off programming effort and support infrastructure, and (ii) crowd workers generally lack a tight feedback loop with their task. In this paper, we introduce Legion, a system that allows end users to easily capture existing GUIs and outsource them for collaborative, real-time control by the crowd. We present mediation strategies for integrating the input of multiple crowd workers in real-time, evaluate these mediation strategies across several applications, and further validate Legion by exploring the space of novel applications that it enables.
Modeling, control, and optimization: Critical technologies in semiconductor manufacturing

Summary form only given. The paper begins by reviewing the design and manufacturing flow for modern integrated circuits. We then describe the vital role played by modeling, control, and optimization technologies in this design/manufacturing flow. Next, we present our efforts in developing metrology for lithography and plasma etching applications. These include temperature, etch-rate, and thermal flux sensors. Our sensors are fully self-contained with on board power, communications, and signal processing electronics. They externally resemble standard silicon wafers compatible with standard cassette-to-cassette robotics, and thus require no equipment modification for deployment. The sensors we have developed offer very fine spatial and time resolution, making them suitable for process optimization and control. We describe our efforts in using these sensors for feedback control of the photolithography process. We then discuss our efforts at commercializing this technology. We close with an overview of our most recent work on modeling, optimization, and control for a variety of problems including inverse lithography, proximity correction, double patterning, and design rule checking.
Multiparty computation with faulty majority

We address the problem of performing a multiparty computation when more than half of the processors are cooperating Byzantine faults. We show how to compute any boolean function of n inputs distributively, preserving the privacy of inputs held by nonfaulty processors, and ensuring that faulty processors obtain the function value "if and only if" the nonfaulty processors do. If the nonfaulty processors do not obtain the correct function value, they detect cheating with high probabihty. Our solution is based on a new type of verifiable secret sharing in which the secret is revealed not all at once but in small increments. This slow-revealing process ensures that all processors discover the secret at roughly the same time. Our solution assumes the existence of an oblivious transfer protocol and uses broadcast channels. We do not require that the processors have equal computing power.
CC-1065 AND THE DUOCARMYCINS : UNDERSTANDING THEIR BIOLOGICAL FUNCTION THROUGH MECHANISTIC STUDIES

We review here studies defining the DNA alkylation properties of a class of potent antitumor antibiotics that includes CC-1065 and the duocarmycins, as well as investigations that delineate fundamental relationships between their structure, functional reactivity, and biological properties. In conjunction with the study of the natural products themselves, the examination of synthetic agents containing deep-seated structural changes, the unnatural enantiomers of the natural products, and related analogs has defined the structural basis for the sequence selective alkylation of duplex DNA and proved to be the key to understanding the fundamental relationships between chemical structure, functional reactivity, and biological properties. The characteristic DNA alkylation proceeds by reversible, stereoelectronically controlled adenine-N3 addition to the least substituted carbon of the activated cyclopropane within AT-rich minor groove sites. Both the natural and unnatural enantiomers alkylate DNA, and the sequence selectivity of both is controlled and dominated by the preferential noncovalent binding of the agents within the narrower, deeper, AT-rich minor groove and the steric accessibility to the alkylation site on penetration of this groove. Among the fundamental relationships between structure and properties, the most striking is the direct relationship between chemical or functional stability and biological potency. Within a short time, simplified and readily accessible synthetic agents rationally based on the natural product leads have been developed, which exhibit comparable and exceptional biological potency (IC50 = 50 to 51 pM) and improved efficacy. The fundamental relationships that have been defined to date can be expected to provide the foundation for future developments and advances.
Unconstrained receding-horizon control of nonlinear systems

It is well known that unconstrained infinite-horizon optimal control may be used to construct a stabilizing controller for a nonlinear system. We show that similar stabilization results may be achieved using unconstrained finite horizon optimal control. The key idea is to approximate the tail of the infinite horizon cost-to-go using, as terminal cost, an appropriate control Lyapunov function. Roughly speaking, the terminal control Lyapunov function (CLF) should provide an (incremental) upper bound on the cost. In this fashion, important stability characteristics may be retained without the use of terminal constraints such as those employed by a number of other researchers. The absence of constraints allows a significant speedup in computation. Furthermore, it is shown that in order to guarantee stability, it suffices to satisfy an improvement property, thereby relaxing the requirement that truly optimal trajectories be found. We provide a complete analysis of the stability and region of attraction/operation properties of receding horizon control strategies that utilize finite horizon approximations in the proposed class. It is shown that the guaranteed region of operation contains that of the CLF controller and may be made as large as desired by increasing the optimization horizon (restricted, of course, to the infinite horizon domain). Moreover, it is easily seen that both CLF and infinite-horizon optimal control approaches are limiting cases of our receding horizon strategy. The key results are illustrated using a familiar example, the inverted pendulum, where significant improvements in guaranteed region of operation and cost are noted.
Synthesis of Complex and Diverse Compounds through Ring Distortion of Abietic Acid

Many compound screening collections are populated by members that possess a low degree of structural complexity. In an effort to generate compounds that are both complex and diverse, we have developed a strategy that uses natural products as a starting point for complex molecule synthesis. Herein we apply this complexity-to-diversity approach to abietic acid, an abundant natural product used commercially in paints, varnishes, and lacquers. From abietic acid we synthesize a collection of complex (as assessed by fraction of sp(3) -hybridized carbons and number of stereogenic centers) and diverse (as assessed by Tanimoto analysis) small molecules. The 84 compounds constructed herein, and those created through similar efforts, should find utility in a variety of biological screens.
Kinetic energy density functionals for non-periodic systems

Abstract Kinetic energy functionals of the electronic density are used to model large systems in the context of density functional theory, without the need to obtain electronic wavefunctions. We discuss the problems associated with the application of widely used kinetic energy functionals to non-periodic systems. We develop a method that circumvents this difficulty and allows the kinetic energy to be evaluated entirely in real space. We demonstrate that the method is efficient [ O ( N )] and accurate by comparing the results of our real-space formulation to calculations performed in reciprocal space, and to calculations using traditional approaches based on electronic states.
A Geometrically Nonlinear Theory of Elastic Plates

A set of kinematical and intrinsic equilibrium equations are derived for plates undergoing large deflection and rotation but with small strain
Radio galaxies and the acceleration of the universe beyond a redshift of one

Radio galaxies provide a means to determine the coordinate distance, the luminosity distance, the dimension-less luminosity distance, or the angular size distance to sources with redshifts as large as two. Dimensionless coordinate distances for 55 supernovae and 20 radio galaxies are presented and discussed here. The radio galaxy results are consistent with those obtained using supernovae, suggesting that neither method is plagued by unknown systematic errors. The acceleration parameter q(z) and the expansion rate H(z) or dimensionless expansion rate E(z) can be determined directly from the data without having to make assumptions regarding the nature or evolution of the ‘‘dark energy’’. The expansion rate E(z) can be determined from the first derivative of the dimensionless coordinate distance, (dy/dz) � 1 , and the acceleration parameter can be determined from a combination of the first and second derivatives of the dimensionless coordinate distance. A model-independent determination of E(z) will allow the properties and redshift evolution of the ‘‘dark energy’’ to be determined, and a model-independent determination of q(z) will allow the redshift at which the universe transitions from acceleration to deceleration to be determined directly. Determination of E(z) and q(z) may also elucidate possible systematic errors in the determinations of the dimensionless coordinate distances. � 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
BIARYL FORMATION USING THE SUZUKI PROTOCOL : CONSIDERATIONS OF BASE, HALIDE, AND PROTECTING GROUP

Abstract The generation of aryl anions prior to quenching with a trialkyl borate has been shown to be sensitive to the composition of the aryl substrate. Aryl iodides containing remote benzyl ether substituants undergo trans -metallation with sec -BuLi to cleanly give the desired aryl anions whereas the corresponding bromides afford appreciable quantities of dianionic intermediates. The aryl boronic acids derived from alkylation of these anions subsequently undergo a palladium mediated coupling with aryl halides to provide good yields of the desired biaryls.
Static Analysis of Object References in RMI-Based Java Software

Distributed applications provide numerous advantages related to software performance, reliability, interoperability, and extensibility. This paper focuses on distributed Java programs built with the help of the remote method invocation (RMI) mechanism. We consider points-to analysis for such applications. Points-to analysis determines the objects pointed to by a reference variable or a reference object field. Such information plays a fundamental role as a prerequisite for many other static analyses. We present the first theoretical definition of points-to analysis for RMI-based Java applications, and we present an algorithm for implementing a flow- and context-insensitive points-to analysis for such applications. We also discuss the use of points-to information for corrupting call graph information, for understanding data dependencies due to remote memory locations, and for identifying opportunities for improving the performance of object serialization at remote calls. The work described in this paper solves one key problem for static analysis of RMI programs and provides a starting point for future work on improving the understanding, testing, verification, and performance of RMI-based software
Scheduling bulk file transfers with start and end times

The advancement of optical networking technologies has enabled e-science applications that often require transport of large volumes of scientific data. In support of such data-intensive applications, we develop and evaluate control plane algorithms for scheduling bulk file transfers, where each transfer has a start time and an end time. We formulate the scheduling problem as a special type of the multi-commodity flow problem. To cope with the start and end time constraints of the file-transfer jobs, we divide time into uniform time slices. Bandwidth is allocated to each job on every time slice and is allowed to vary from slice to slice. This enables periodical adjustment of the bandwidth assignment to the jobs so as to improve a chosen performance objective: throughput of the concurrent transfers. In this paper, we study the effectiveness of using multiple time slices, the performance criterion being the tradeoff between achievable throughput and the required computation time. Furthermore, we investigate using multiple paths for each file transfer to improve the throughput. We show that using a small number of paths per job is generally sufficient to achieve near optimal throughput with a practical execution time, and this is significantly higher than the throughput of a simple scheme that uses single shortest path for each job.
Agency Costs, Risk Management, and Capital Structure

The joint determination of capital structure and investment risk is examined. Optimal capital structure reflects both the tax advantages of debt less default costs (Modigliani and Miller (1958, 1963)), and the agency costs resulting from asset substitution (Jensen and Meckling (1976)). Agency costs restrict leverage and debt maturity and increase yield spreads, but their importance is small for the range of environments considered. Risk management is also examined. Hedging permits greater leverage. Even when a firm cannot precommit to hedging, it will still do so. Surprisingly, hedging benefits often are greater when agency costs are low. THE CHOICE OF INVESTMENT FINANCING, and its link with optimal risk exposure, is central to the economic performance of corporations. Financial economics has a rich literature analyzing the capital structure decision in qualitative terms. But it has provided relatively little specific guidance. In contrast with the precision offered by the Black and Scholes (1973) option pricing model and its extensions, the theory addressing capital structure remains distressingly imprecise. This has limited its application to corporate decision making. Two insights have profoundly shaped the development of capital structure theory. The arbitrage argument of Modigliani and Miller (M-M) (1958, 1963) shows that, with fixed investment decisions, nonfirm claimants must be present for capital structure to affect firm value. The optimal amount of debt balances the tax deductions provided by interest payments against the external costs of potential default. Jensen and Meckling (J-M) (1976) challenge the M-M assumption that investment decisions are independent of capital structure. Equityholders of a levered firm, for example, can potentially extract value from debtholders by increasing investment risk after debt is in place: the "asset substitution" problem. Such predatory behavior creates agency costs that the choice of capital structure must recognize and control.
Small-signal analysis and control design of isolated power supplies with optocoupler feedback

Optocouplers are widely used in isolated power supplies to transfer the feedback signal from the secondary to the primary side. In many power supplies, the feedback amplifier is supplied from the output voltage that creates additional feedback path which should be taken into account in the control design. The paper presents a detailed analysis and control design for each of the two possible feedback loops that can be identified. In addition, dynamic limitations of the TL431 shunt regulator and of the optocoupler are discussed. Practical guidelines for the error amplifier design and a design example are presented for both voltage-mode and current-mode controls.
Going Through Rough Times: from Non-Equilibrium Surface Growth to Algorithmic Scalability

Efficient and faithful parallel simulation of large asynchronous systems is a challenging computational problem. It requires using the concept of local simulated times and a synchronization scheme. We study the scalability of massively parallel algorithms for discrete-event simulations which employ conservative synchronization to enforce causality. We do this by looking at the simulated time horizon as a complex evolving system, and we identify its universal characteristics. We find that the time horizon for the conservative parallel discrete-event simulation scheme exhibits Kardar-Parisi-Zhang-like kinetic roughening. This implies that the algorithm is asymptotically scalable in the sense that the average progress rate of the simulation approaches a non-zero constant. It also implies, however, that there are diverging memory requirements associated with such schemes.
Interlacing families II: Mixed characteristic polynomials and the Kadison{Singer problem

We use the method of interlacing polynomials introduced in our previous article to prove two theorems known to imply a positive solution to the Kadison{Singer problem. The rst is Weaver’s conjecture KS 2, which is known to imply Kadison{Singer via a projection paving conjecture of Akemann and Anderson. The second is a formulation due to Casazza et al. of Anderson’s original paving conjecture(s), for which we are able to compute explicit paving bounds. The proof involves an analysis of the largest roots of a family of polynomials that we call the \mixed characteristic polynomials" of a collection of matrices.
Children of Lesbian and Gay Parents

What kinds of home environments are best able to support children’s psychological adjustment and growth? This question has long held a central place in the field of research on child development. Researchers in the United States have often assumed that the most favorable home environments are provided by white, middle-class, two-parent families, in which the father is paid to work outside the home but the mother is not. Although rarely stated explicitly, it has most often been assumed that both parents in such families are heterosexual.
Joint Monitoring and Routing in Wireless Sensor Networks Using Robust Identifying Codes

Wireless Sensor Networks (WSNs) provide an important means of monitoring the physical world, but their limitations present challenges to fundamental network services such as routing. In this work we utilize an abstraction of WSNs based on the theory of identifying codes. This abstraction has been useful in recent literature for a number of important monitoring problems, such as localization and contamination detection. In our case, we use it to provide a joint infrastructure for efficient and robust monitoring and routing in WSNs. Specifically, we make use of efficient and distributed algorithm for generating robust identifying codes, an NP-hard problem, with a logarithmic performance guarantee based on a reduction to the set k-multicover problem. We also show how this same identifying-code infrastructure provides a natural labeling that can be used for near-optimal routing with very small routing tables. We provide experimental results for various topologies that illustrate the superior performance of our approximation algorithms over previous identifying code heuristics.
Vesicoureteral Reflux in Older Children: Concordance of US and Voiding Cystourethrographic Findings

PURPOSE: To determine if a negative renal sonogram is reliably predictive of the absence of vesicoureteral reflux at voiding cystourethrography (VCUG) in children aged 5 years or older. MATERIALS AND METHODS: Imaging studies in 70 children aged 5 years or older who underwent renal ultrasound (US) and VCUG on the same day were reviewed. These children had initially undergone evaluation because of a urinary tract infection. RESULTS: Five of 70 children had abnormal sonograms; two (40%) of the five had reflux at VCUG. One had mild pelvicalyceal dilatation, and one had a small kidney. The other three (without reflux) had a pelvic kidney, a calyceal diverticulum, or a renal stone. Of 65 children with a negative sonogram, 19 (29%) had reflux at VCUG; 46 (71%) did not. Altogether, of the 70 children, 21 had reflux, 19 (90%) of whom had no sonographic abnormality. CONCLUSION: Children with abnormal screening renal sonograms often have vesicoureteral reflux, but a normal sonogram does not reliably exclude the cond...
Investigation of Initial Lithiation of Silicon (100) Using Solid-State 7Li NMR

Structural changes in amorphous LixSi during the initial lithiation of single crystal Si to amorphous LixSi were investigated as a function of Li flux and total charge using solid-state 7 Li nuclear magnetic resonance (NMR) spectroscopy. Single crystal (100) Si wafers were used as a model system in this study, as the Li flux could be precisely controlled and uniformly distributed across the surface of the wafer. It was observed that peak shifts in solid-state 7 Li NMR spectra varied as a function of the Li flux during the initial lithiation and stayed constant for samples of the same Li flux regardless of the total charge applied to the electrodes. We conclude from these results that the Li concentration in LixSi stays constant for a given flux regardless of the total coulombic charge applied to the electrode. The results from this study help better understand the kinetics, the reaction mechanisms, and the kinetic modeling of chemical reactions at the reaction front during the initial lithiation of Si (100).
Particulate damping in solid propellant combustion instability

The effect of aluminum powder in damping high-frequency solid-propellant instability has been investigated in a vortex burner developed previously. The combustor was composed of a main chamber having a shallow center-perforated grain and a hot gas generator. The generator fed combustion gases tangentially into the main chamber causing transverse mode combustion instability. Aluminum powder was added either to the main propellant or to the gas generator charge. Measurement of the amplitude of the pressure oscillations indicated the effectiveness of the metal acting 1) as an ingredient at the solid surface and in the gas phase and 2) in the gas phase only. In the absence of aluminum the combustor was unstable, exhibiting an oscillation frequency of ^3800 cps with a peak-to-peak amplitude of 55%. The addition of fine aluminum powder to the propellant in the main chamber was sufficient to damp out the high-frequency instability. Addition of aluminum to the gas generator propellant only was also effective in eliminating instability provided that an equivalent concentration of metal particles was added. It was concluded that the addition of aluminum powder to composite solid propellants suppresses instability by acting as an attenuator of sound in the gas phase rather than altering the driving or response of the propellants. Viscous damping is inferred to be the principal damping mechanism. Addition of the aluminum produced a nonacoustic disturbance which appeared to be eliminated at higher operating pressures.
Materials Requirements for IR Detectors and Imagers

The requirements of infrared systems have increased significantly over the years, from the simple linear, low resolution, photoconductive array to the present-day, large area, high-density, photodiode (MIS and metalurgical) arrays, with on-focal-plane signal processing of considerable complexity. The success that has been achieved in meeting the performance goals appropriate for these systems has been due, to a large degree, to significant advances in the relevant materials technologies. The technologies of importance over the last twenty years are briefly reviewed, and the current state of the art, with its dominance by intrinsic alloy materials, is addressed in detail. The limitations of current bulk and epitaxial intrinsic materials technologies are considerable, both from a performance and a producibility point of view, when compared to the quality and quantity of material required by future infrared systems. These limitations are considered together with possible ways to overcome them.
Neutron Star Mass Measurements. I. Radio Pulsars

There are now about 50 known radio pulsars in binary systems, including at least five in double neutron star binaries. In some cases, the stellar masses can be directly determined from measurements of relativistic orbital effects. In others, only an indirect or statistical estimate of the masses is possible. We review the general problem of mass measurement in radio pulsar binaries and critically discuss all current estimates of the masses of radio pulsars and their companions. We find that significant constraints exist on the masses of 21 radio pulsars and on five neutron star companions of radio pulsars. All the measurements are consistent with a remarkably narrow underlying Gaussian mass distribution, m=1.35?0.04 M. There is no evidence that extensive mass accretion (?m0.1 M) has occurred in these systems. We also show that the observed inclinations of millisecond pulsar binaries are consistent with a random distribution, and thus find no evidence for either alignment or counteralignment of millisecond pulsar magnetic fields.
Local government policies and migration: Reply and extension

This study empirically investigates the impact of higher property taxation on net in-migration to SMSAs over the 1965-70 time period. Using two stage least squares, the estimation reveals that net migration is a decreasing function of the per capita level of property taxes. This provides additional support for the theory of voting with one's feet.
calclens: weak lensing simulations for large-area sky surveys and second-order effects in cosmic shear power spectra

I present a new algorithm, CALCLENS, for efficiently computing weak gravitational lensing shear signals from large N-body light cone simulations over a curved sky. This new algorithm properly accounts for the sky curvature and boundary conditions, is able to produce redshift-dependent shear signals including corrections to the Born approximation by using multiple-plane ray tracing, and properly computes the lensed images of source galaxies in the light cone. The key feature of this algorithm is a new, computationally efficient Poisson solver for the sphere that combines spherical harmonic transform and multgrid methods. As a result, large areas of sky (~10, 000 square degrees) can be ray traced efficiently at high-resolution using only a few hundred cores on widely available machines. Using this new algorithm and curved-sky calculations that only use a slower but more accurate spherical harmonic transform Poisson solver, I study the shear B-mode and rotation mode power spectra. Employing full-sky E/B-mode decompositions, I confirm that the shear B-mode and rotation mode power spectra are equal at high accuracy (~1%), as expected from perturbation theory up to second order. Coupled with realistic galaxy populations placed in large N-body light cone simulations, this new algorithm is ideally suited for the construction of synthetic weak lensing shear catalogs to be used to test for systematic effects in data analysis procedures for upcoming large-area sky surveys. The implementation presented in this work, written in C and employing widely available software libraries to maintain portability, is publicly available at this http URL
From judicial comity to legal comity: A judicial solution to global disorder?

Multifarious definitions and different practices are associated with the notion of “judicial comity.” Nevertheless, this paper seeks to demonstrate the existence of a key feature of the phenomenon. The analysis of cases illustrates that the implementation of certain judicial techniques expresses a court's “regulating function,” which is aimed at governing the relations between different legal systems within the global legal space, specifically when the codified criteria regulating those relations are lacking or insufficient. It is an original approach, which allows us to identify the new boundaries of the phenomenon—distinguishing between the techniques that are effectively an expression of judicial comity and those which are not—and, consequently, to depart from the definitions elaborated by a certain jurisprudence and the pertinent literature. From this standpoint, judicial comity produces the interesting effect of “legal comity,” which can lead to a mitigation of the disorder characterizing the global legal space. At the same time, this perspective gives rise to some questions, for example, related to the real value of the phenomenon and the existence of extrajudicial interests behind the application of the techniques.
Scan predictive vector quantization of multispectral images

Conventional vector quantization (VQ)-based techniques partition an image into nonoverlapping blocks that are then raster scanned and quantized. Image blocks that contain an edge result in high-frequency vectors. The coarse representation of such vectors leads to visually annoying degradations in the reconstructed image. The authors present a solution to the edge-degradation problem based on some earlier work on scan models. The approach reduces the number of vectors with abrupt intensity variations by using an appropriate scan to partition an image into vectors. They show how their techniques can be used to enhance the performance of VQ of multispectral data sets. Comparisons with standard techniques are presented and shown to give substantial improvements.
Elite Influence? Religion, Economics, and the Rise of the Nazis

Adolf Hitler's seizure of power was one of the most consequential events of the twentieth century. Yet, our understanding of which factors fueled the astonishing rise of the Nazis remains highly incomplete. This paper shows that religion played an important role in the Nazi party's electoral success -- dwarfing all available socioeconomic variables. To obtain the first causal estimates we exploit plausibly exogenous variation in the geographic distribution of Catholics and Protestants due to a peace treaty in the sixteenth century. Even after allowing for sizeable violations of the exclusion restriction, the evidence indicates that Catholics were significantly less likely to vote for the Nazi Party than Protestants. Consistent with the historical record, our results are most naturally rationalized by a model in which the Catholic Church leaned on believers to vote for the democratic Zentrum Party, whereas the Protestant Church remained politically neutral.
Three‐dimensional, randomized, network model for two‐phase flow through porous media

A structural model for a porous medium in the form of a randomized, three-dimensional network is developed that can be used to calculate permeability, capillary pressure as measured under static conditions and during steady-state flows, and relative permeabilities as measured during steady-state flows. This randomized network model, expressed in terms of seven free parameters, can be employed to correlate for a given system the single-phase permeability, the drainage and imbibition capillary pressure curves, and the two drainage relative permeability curves. The subsequent portions of the hysteresis loops for capillary pressure and for the relative permeabilities then can be predicted. The limited data available from the literature for unconsolidated packed beds have been successfully correlated: 100 to 200 mesh sand and uniform 181 μm glass spheres. Data for a bed of sintered 200 μm glass beads also has been successfully described.
Parallel breadth-first search on distributed memory systems

Data-intensive, graph-based computations are pervasive in several scientific applications, and are known to to be quite challenging to implement on distributed memory systems. In this work, we explore the design space of parallel algorithms for Breadth-First Search (BFS), a key subroutine in several graph algorithms. We present two highly-tuned parallel approaches for BFS on large parallel systems: a level-synchronous strategy that relies on a simple vertex-based partitioning of the graph, and a two-dimensional sparse matrix partitioning-based approach that mitigates parallel communication overhead. For both approaches, we also present hybrid versions with intra-node multithreading. Our novel hybrid two-dimensional algorithm reduces communication times by up to a factor of 3.5, relative to a common vertex based approach. Our experimental study identifies execution regimes in which these approaches will be competitive, and we demonstrate extremely high performance on leading distributed-memory parallel systems. For instance, for a 40,000-core parallel execution on Hopper, an AMD Magny-Cours based system, we achieve a BFS performance rate of 17.8 billion edge visits per second on an undirected graph of 4.3 billion vertices and 68.7 billion edges with skewed degree distribution.
FT-MPI, fault-tolerant metacomputing and generic name services: a case study

There is a growing interest in deploying MPI over very large numbers of heterogenous, geographically distributed resources. FT-MPI provides the fault-tolerance necessary at this scale, but presents some issues when crossing multiple administrative domains. Using the H2O metacomputing framework, we add cross-administrative domain interoperability and “pluggability” to FT-MPI. The latter feature allows us, using proxies, to transparently replace one vulnerable module – its name service – with fault-tolerant replacements. We present an algorithm for improving performance of operations over the proxies. We evaluate its performance in a comparison using the original name service, OpenLDAP and current Emory research project HDNS.
Debt Relief and the Current Account: An Analysis of the HIPC Initiative

In this paper I develop a model to investigate the connection between debt relief and current account sustainability. This model can be used as a key input in assessing whether a HIPC country’s real exchange rate is ‘overvalued,’ and will thus need to go through devaluation. The working of the model is illustrated for the case of Nicaragua, a country that in 2002 had one of the highest external debt to GDP ratios: almost 300 per cent. Nicaragua is the second poorest country in the Western Hemisphere (after Haiti), and for the last decade has relied very heavily on foreign assistance and aid. Moreover, in the last few years Nicaragua has run extremely large current account deficits in excess of 37 per cent of GDP during 1997-2001 largely financed by grants, donations and migrant remittances.
Efficient fluoride-mediated synthesis of 5-alkyl amino- and ether-substituted pyrazoles

Abstract Fluoride-mediated nucleophilic substitution reactions of 1-(4-methylsulfonyl (or sulfonamido)-2-pyridyl)-5-chloro-4-cyano pyrazoles with various amines and alcohols occur under mild conditions to provide the 5-alkyl amino and ether pyrazoles in moderate to high yields.
Propagation of Data Error and Parametric Sensitivity in Computable General Equilibrium Models

While computable general equilibrium (CGE) models are a well-established tool in economic analyses, it is often difficult to disentangle the effects of policies of interest from that of the assumptions made regarding the underlying calibration data and model parameters. To characterize the behavior of a CGE model of carbon output with respect to two of these assumptions, we perform a large-scale Monte Carlo experiment to examine its sensitivity to base year calibration data and elasticity of substitution parameters in the absence of a policy change. By examining a variety of output variables at different levels of economic and geographic aggregation, we assess how these forms of uncertainty impact the conclusions that can be drawn from the model simulations. We find greater sensitivity to uncertainty in the elasticity of substitution parameters than to uncertainty in the base-year data as the projection period increases. While many model simulations were conducted to generate large output samples, we find that few are required to capture the mean model response of the variables tested. However, characterizing standard errors and empirical probability distribution functions is not possible without a large number of simulations.
Strongly Hyperbolic Extensions of the ADM Hamiltonian

The ADM Hamiltonian formulation of general relativity with prescribed lapse and shift is a weakly hyperbolic system of partial differential equations. In general weakly hyperbolic systems are not mathematically well posed. For well posedness, the theory should be reformulated so that the complete system, evolution equations plus gauge conditions, is (at least) strongly hyperbolic. Traditionally, reformulation has been carried out at the level of equations of motion. This typically destroys the variational and Hamiltonian structures of the theory. Here I show that one can extend the ADM formalism to (a) incorporate the gauge conditions as dynamical equations and (b) affect the hyperbolicity of the complete system, all while maintaining a Hamiltonian description. The extended ADM formulation is used to obtain a strongly hyperbolic Hamiltonian description of Einstein’s theory that is generally covariant under spatial diffeomorphisms and time reparametrizations, and has physical characteristics. The extended Hamiltonian formulation with 1+ log slicing and gamma-driver shift conditions is weakly hyperbolic.