cssi/SciSciGPT-SciSciNet huggingface dataset:
Three-point current correlation functions as probes of effective conformal theories

The first sub-leading, order $ {1 \left/ {{\sqrt{\lambda }}} \right.} $ correction to the three-point current correlation function $ \left\langle {J_i^a(x)J_j^b(y)J_k^c(z)} \right\rangle $ of a strongly coupled conformal system with non-Abelian global symmetry is shown to come uniquely from the non-renormalizable bulk operator $ {{\left( {{F_{{\mu \nu }}}} \right)}^3} $ . The non-renormalizable correction is suppressed by powers of the cutoff scale Λ of the bulk effective theory, which corresponds to a dimension cutoff Δ = R AdSΛ in the boundary effective conformal theory. The contribution of the non-renormalizable term to the three-point function is calculated from the weakly coupled AdS dual in the large N limit. It is shown to have a polarization structure different from the leading contribution, which comes from the renormalizable $ {{\left( {{F_{{\mu \nu }}}} \right)}^2} $ operator. This suggests a possible experimental probe of the effective conformal description through a measurement of the cutoff dimension Δ in strongly coupled condensed matter systems.
Performance analysis of a noncoherently combined large aperture optical heterodyne receiver

The performance of a noncoherently combined, multiple-mirror heterodyne receiver is analyzed. In the absence of atmospheric turbulence, the performance of the noncoherently combined receiver is shown to be inferior to that of a monolithic, diffraction-limited receiver with equivalent aperture area. when atmospheric turbulence is taken into consideration, however, the efficiency of a monolithic aperture heterodyne receiver, is limited by the phase coherence length of the atmosphere, and generally does not improve with increasing aperture size. In contrast, the performance of a noncoherently combined system improves with an increasing number of receivers. Consequently, given a fixed collecting area, the noncoherently combined system can offer a superior performance. The performance of the noncoherently combined heterodyne receiver is studied by analyzing the combining loss of the receiver SNR (signal-to-noise ratio). It is shown that, given a constant collecting area, the performance of the combined receiver is optimized when the diameter of each of the individual receivers is on the order of the phase coherence length r/sub 0/ of the atmospheric turbulence. >
The Timeliness and Cost-Effectiveness of the Local and Regional Procurement of Food Aid

Summary Local and regional procurement (LRP) of food aid is often claimed to lead to quicker and more cost-effective response. We generate timeliness and cost-effectiveness estimates by comparing US-funded LRP activities in nine countries against in-kind, transoceanic food aid shipments from the US to the same countries during the same timeframe. Procuring food locally or distributing cash or vouchers results in a time savings of nearly 14 weeks, a 62 percent gain. Cost-effectiveness varies significantly by commodity type. Procuring grains locally saved over 50 percent, on average, while local procurement of processed commodities was not always cost-effective.
Analysis of Multiple-Antenna Systems With Finite-Rate Feedback Using High-Resolution Quantization Theory

This paper considers the development of a general framework for the analysis of transmit beamforming methods in multiple-antenna systems with finite-rate feedback. Inspired by the results of classical high-resolution quantization theory, the problem of finite-rate quantized communication system is formulated as a general fixed-rate vector quantization problem with side information available at the encoder (or the quantizer) but unavailable at the decoder. The framework of the quantization problem is sufficiently general to include quantization schemes with general non-mean-squared distortion functions and constrained source vectors. Asymptotic distortion analysis of the proposed general quantization problem is provided by extending the vector version of the Bennett's integral. Specifically, tight lower and upper bounds of the average asymptotic distortion are proposed. Sufficient conditions for the achievability of the distortion bounds are also provided and related to corresponding classical fixed-rate quantization problems. The proposed general methodology provides a powerful analytical tool to study a wide range of finite-rate feedback systems. To illustrate the utility of the framework, we consider the analysis of a finite-rate feedback multiple-input single-output (MISO) beamforming system over independent and identically distributed (i.i.d.) Rayleigh flat-fading channels. Numerical and simulation results are presented that further confirm the accuracy of the analytical results
Chandra/HETGS Observations of the Capella System: The Primary as a Dominating X-Ray Source

Using the Chandra/High Energy Transmission Grating Spectrometer (HETGS), we have detected the Doppler motion of Capella's X-ray emission lines in the 6-25 A wave band. The observed motion follows the expected orbital motion of Capella's primary. This finding implies that the primary G8 III star, not the secondary G1 III star in the Hertzsprung gap, has been the dominant source of hot 106.8-107 K plasma at least in the last 6 years. In addition, the results demonstrate the long-term stability of the HETGS, and they demonstrate small uncertainties of 25 and 33 km s-1 in the velocity determination with the High and Medium Energy Gratings (HEG and MEG), respectively.
Blade Three-Dimensional Dynamic Stall Response to Wind Turbine Operating Condition

To further reduce the cost of wind energy, future turbine designs will continue to migrate toward lighter and more flexible structures. Thus, the accuracy and reliability of aerodynamic load prediction has become a primary consideration in turbine design codes. Dynamically stalled flows routinely generated during yawed operation are powerful and potentially destructive, as well as complex and difficult to model. As a prerequisite to aerodynamics model improvements, wind turbine dynamic stall must be characterized in detail and thoroughly understood. The current study analyzed turbine blade surface pressure data and local inflow data acquired by the NREL Unsteady Aerodynamics Experiment during the NASA Ames wind tunnel experiment. Analyses identified and characterized two key dynamic stall processes, vortex initiation and vortex convection, across a broad parameter range. Results showed that both initiation and convection exhibited pronounced three-dimensional kinematics, which responded in systematic fashion to variations in wind speed, turbine yaw angle, and radial location.
Nonclassical 2,4-diamino-8-deazafolate analogues as inhibitors of dihydrofolate reductases from rat liver, Pneumocystis carinii, and Toxoplasma gondii.

The synthesis and biological activity of 42 6-substituted-2,4-diaminopyrido[3,2-d]pyrimidines (2,4-diamino-8-deazafolate analogues) are reported. The compounds were synthesized in improved yields c...
A Bioinspired Ugi/Michael/Aza‐Michael Cascade Reaction in Aqueous Media: Natural‐Product‐like Molecular Diversity

The two-stage microwave irradiation yields polycyclic N-heterocycles as skeletons of natural substances.
Three-dimensional subband coding of video using the zero-tree method

In this paper, a simple yet highly effective video compression technique is presented. The zerotree method by Said, which is an improved version of Shapiro's original one, is applied and expanded to three-dimension to encode image sequences. A three-dimensional subband transformation on the image sequences is first performed, and the transformed information is then encoded using the zerotree coding scheme. The algorithm achieves results comparable to MPEG-2, without the complexity of motion compensation. The reconstructed image sequences have no blocking effects at very low rates, and the transmission is progressive.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Dark Energy Constraints from Weak-Lensing Cross-Correlation Cosmography

We present a method for implementing the idea of Jain & Taylor for constraining cosmological parameters with weak gravitational lensing. Photometric redshift information on foreground galaxies is used to produce templates of the mass structure at foreground slices zl, and the predicted distortion field is cross-correlated with the measured shapes of sources at redshift zs. The variation of the cross-correlation with zs depends purely on ratios of angular diameter distances. We propose a formalism for such an analysis that makes use of all foreground-background redshift pairs and derive the Fisher uncertainties on the dark energy parameters that would result from such a survey. Surveys from the proposed Supernova/Acceleration Probe (SNAP) satellite or the Large Synoptic Survey Telescope (LSST) observatory could constrain the dark energy equation of state to σ ≈ 0.01f and σ ≈ 0.035f after application of a practical prior on Ωm. Advantages of this method over power-spectrum measurements are that it is unaffected by residual point-spread function distortions, is not limited by sample variance, and can use nonlinear mass structures to constrain the cosmology. The signal is, however, very small, amounting to a change of a few parts in 103 of the lensing distortion. In order to realize the full sensitivity to cosmological parameters, the calibration of lensing distortion must be independent of redshift to comparable levels, and photometric redshifts must be similarly free of bias. Both of these tasks require substantial advances over the present state of the art, but we discuss how such accurate calibrations might be achieved using internal consistency tests. Elimination of redshift bias would require the spectroscopic redshifts of ~104-105 high-redshift galaxies—fewer for lensing surveys less ambitious than SNAP or LSST.
Angle-Resolved XPS Studies of Interfacial Bonding States in Silicon oxynitrides Fabricated Using Different Thermal Methodologies

Silicon oxynitride films, fabricated by direct thermal growth and annealing in N2O or NO, were analyzed by Angle-Resolved X-ray Photoelectron Spectroscopy (ARXPS). It is seen that for the samples processed in N2O, N is bonded as Si3N4 only, irrespective of whether the fabrication was done on bare Si or on an oxide pre-grown in O2. But the films processed in NO depict additional bonding arrangements, namely, non-stoichiometric SiOxNy, (Si-)2-N-O, and Si-N(-O)2. These bonding states are found to be concentrated in a higher proportion above the oxynitride/substrate interface. Further, it is seen that annealing of a pre-grown oxide in NO for 30 min incorporates the same bonding states as by direct growth in NO for as long as 120 min. Also, a critical N concentration (between 1.9% and 2.3%) is required for the incorporation of the Si-N(-O)2 structure, observed at 400.7 eV. Besides enhancing the overall understanding of the progress of silicon oxynitridation process in N2O and NO, these findings can help significantly towards developing process-property relationships for incorporation of N with the desired bonding state(s) at specific positions within an oxynitride film.
Unequal dimensional small balls and quantization on Grassmann Manifolds

The Grassmann manifold Gn,p (L) is the set of all p-dimensional planes (through the origin) in the n-dimensional Euclidean space Ln, where L is either R or C. This paper considers an unequal dimensional quantization in which a source in Gn,p (L) is quantized through a code in Gn,q (L), where p and q are not necessarily the same. It is different from most works in literature where p = q. The analysis for unequal dimensional quantization is based on the volume of a metric ball in Gn,p (L) whose center is in Gn,q (L). Our chief result is a closed-form formula for the volume of a metric ball when the radius is sufficiently small. This volume formula holds for Grassmann manifolds with arbitrary n, p, q and L, while previous results pertained only to some special cases. Based on this volume formula, several bounds are derived for the rate distortion tradeoff assuming the quantization rate is sufficiently high. The lower and upper bounds on the distortion rate function are asymptotically identical, and so precisely quantify the asymptotic rate distortion tradeoff. We also show that random codes are asymptotically optimal in the sense that they achieve the minimum achievable distortion with probability one as n and the code rate approach infinity linearly. Finally, we discuss some applications of the derived results to communication theory. A geometric interpretation in the Grassmann manifold is developed for capacity calculation of additive white Gaussian noise channel. Further, the derived distortion rate function is beneficial to characterizing the effect of beamforming matrix selection in multi-antenna communications.
Selective catalytic reduction of nitric oxide by propane in oxidizing atmosphere over copper-exchanged zeolites

Abstract Selective catalytic reduction of nitric oxide with propane and oxygen was investigated on Cu-exchanged ZSM-5, mordenite, X-type and Y-type zeolites at temperatures in the range of 200 to 600°C. Catalytic activities of Cu-X and Cu-Y are negligible, activity of Cu-mordenite moderate, and that of Cu-ZSM-5 very high, converting > 90% of nitric oxide to nitrogen at 400°C and at a space velocity of 102 000 h −1 . Effects of space velocity, nitric oxide concentration, C 3 H 8 /NO ratio, oxygen concentration, and water vapor on the activities of Cu-ZSM-5 and Cu-mordenite were investigated. Nitric oxide conversion decreases with increasing space velocity, decreasing propane and nitric oxide concentrations, and decreasing propane/NO ratio. Water vapor decreases the activity significantly at all temperatures. At temperatures above 400°C, propane oxidation by oxygen is a significant competing reaction in decreasing the selectivity for nitric oxide reduction. The results indicate that Cu-ZSM-5 is a promising catalyst for selective catalytic reduction of nitric oxide by hydrocarbons.
Enhanced look-ahead load margin estimation for voltage security assessment

An enhanced method for estimating look-ahead load margin to voltage collapse, due to either saddle-node bifurcation or the limit-induced bifurcation, is proposed. The enhanced method contains improved schemes for accurately estimating the look-ahead load margins to bifurcation points. In addition, the enhanced method proposed in this paper can resolve the difficulty associated with the missing alarm problem. Two new strategies, sensitivity-based selection scheme and the reselection scheme are developed and incorporated into the enhanced method. The enhanced method is applied to a practical 3000-bus power system with promising results.
Measurements of the thermal characteristics of heated offset jets

Abstract A study is presented of the thermal characteristics of a turbulent offset jet impinging onto an adiabatic wall. Detailed temperature distributions are used to draw several conclusions concerning the flow characteristics of the jets. Results are also compared with a heated wall jet flow. The three regions studied are the recirculation, impingement and developing wall jet zones. A scaling of the downstream position is presented which collapses much of the thermal details of the jets. However, it is concluded that variation of the flow curvature coupled with entrainment for different offset ratios restrict the scaling. A local similarity of the temperature profiles is substantiated just downstream of impingement.
Shades of Brown and Green: Party Effects in Proportional Election Systems

Small parties play an important role in proportional election systems. For example, the emergence and electoral success of environmental and anti-immigration parties have constituted one of the central changes in the political landscape in Europe over the last three decades. But we do not know if this has actually had any implications for policy, since no methods exist for credibly estimating the effect of legislative representation in proportional election systems. Because party representation is not randomly assigned, both observable and unobservable factors influence policy outcomes as well as party representation. Using a part of the legislative seat allocation that is as good as random, I estimate the causal effect of party representation on immigration policy, environmental policy and tax policy in Swedish municipalities. The results show that party representation has a large effect on the first two policies, but not on the tax policy.
Synthesis of a 2-aminoimidazole library for antibiofilm screening utilizing the Sonogashira reaction.

The divergent synthesis of a 21-member library composed of 2-aminoimidazole compounds for evaluation as novel antibiofilm molecules is presented. The Sonogashira reaction was employed with three regioisomeric aryl iodides and 11 different alkynes to generate variously substituted diverse ring systems. Good to excellent yields (80−97%) for the reaction were obtained, and the products provide adequate handles for further manipulation into more advanced analogues.
Separation of Core Noise and Jet Noise

A method of identificatio n and measurement of c*re W\«» and let noise separately has been developed based on cross-correlation of signals from microphones located at yi<<My sep 4?ated angles in the far field of a jet. The different coherent properties of core noise and jet! v\o»<*? Aft *&&L fa ^H^ method to achieve this separation. Experimental data obtained in a small scale facility ara 3v&tyt& t$ ^e$tanstrate that this method can be used successfully to separate the mean-square pressures of ccnre «0ise and jet fx/jf^ Nomenclature A = autocorrelation function C = cross-correlation function or Doppler factor in Eq. (3) M = Mach number TV = index in Eq. (10) p = sound pressure q = source fluctuation, Eq. (10) r = radius 5 = spectral density t =time t' = retarded time U,V = velocity W - speed of tape recording a = ratio defined in Eq. (4) /3 = ratio defined in Eq. (5) 6 - density exponent A = difference 6 = angle with respect to the downstream jet axis 0 = angle to the direction of motion (Fig .13) p - density T = time delay \l/ = autocorrelation of moving source w = ciruclar frequency Subscripts and Superscripts
Profits and politics: Coordinating technology adoption in agriculture

Abstract This paper examines the political economy of government-led coordination of economic activity in a simple two-sector model in which individuals' choice of agricultural technology affects industrialization. We demonstrate the existence of multiple equilibria; the economy is either characterized by the use of a traditional agricultural technology and a low level of industrialization or the use of a mechanized technology and a high level of industrialization. Relative to the traditional technology, use of the mechanized technology increases output but leaves some population groups worse off. We show that the distributional implications of choosing the mechanized technology restrict the possibility of Pareto-improving coordination by an elected policy-maker, even when we allow for income redistribution.
Rounding the Corners of the Policy Trilemma: Sources of Monetary Policy Autonomy

A central result in international macroeconomics is that a government cannot simultaneously opt for open financial markets, fixed exchange rates, and monetary autonomy; rather, it is constrained to choosing no more than two of these three. This paper considers whether partial capital controls and limited exchange rate flexibility allow for full monetary policy autonomy. We find partial capital controls do not generally allow for greater monetary control than with open capital accounts, unless they are quite extensive, but a moderate amount of exchange rate flexibility does allow for some degree of monetary autonomy, especially in emerging and developing economies. (JEL E52, F32, F33)
Persistent Monitoring of Events With Stochastic Arrivals at Multiple Stations

This paper introduces a new mobile sensor scheduling problem involving a single robot tasked to monitor several events of interest that are occurring at different locations (stations). Of particular interest is the monitoring of transient events of a stochastic nature, with applications ranging from natural phenomena (e.g., monitoring abnormal seismic activity around a volcano using a ground robot) to urban activities (e.g., monitoring early formations of traffic congestion using an aerial robot). Motivated by examples like these, this paper focuses on problems in which the precise occurrence times of the events are unknown a priori , but statistics for their interarrival times are available. In monitoring such events, the robot seeks to: 1) maximize the number of events observed and 2) minimize the delay between two consecutive observations of events occurring at the same location. This paper considers the case when a robot is tasked with optimizing the event observations in a balanced manner, following a cyclic patrolling route. To tackle this problem, first, assuming that the cyclic ordering of stations is known, we prove the existence and uniqueness of the optimal solution and show that the solution has desirable convergence rate and robustness. Our constructive proof also yields an efficient algorithm for computing the unique optimal solution with $O(n)$ time complexity, in which $n$ is the number of stations, with $O(\log n)$ time complexity for incrementally adding or removing stations. Except for the algorithm, our analysis remains valid when the cyclic order is unknown. We then provide a polynomial-time approximation scheme that computes for any $\epsilon > 0$ a $(1+\epsilon)$ -optimal solution for this more general, NP-hard problem.
The RAND Health Insurance Experiment, Three Decades Later

We re-present and re-examine the analysis from the famous RAND Health Insurance Experiment from the 1970s on the impact of consumer cost sharing in health insurance on medical spending. We begin by summarizing the experiment and its core findings in a manner that would be standard in the current age. We then examine potential threats to the validity of a causal interpretation of the experimental treatment effects stemming from different study participation and differential reporting of outcomes across treatment arms. Finally, we re-consider the famous RAND estimate that the elasticity of medical spending with respect to its out-of-pocket price is −0.2, emphasizing the challenges associated with summarizing the experimental treatment effects from non-linear health insurance contracts using a single price elasticity.
Privacy and Truthful Equilibrium Selection for Aggregative Games

We study a very general class of games -- multi-dimensional aggregative games -- which in particular generalize both anonymous games and weighted congestion games. For any such game that is also large, we solve the equilibrium selection problem in a strong sense. In particular, we give an efficient weak mediator: a mechanism which has only the power to listen to reported types and provide non-binding suggested actions, such that a it is an asymptotic Nash equilibrium for every player to truthfully report their type to the mediator, and then follow its suggested action; and b that when players do so, they end up coordinating on a particular asymptotic pure strategy Nash equilibrium of the induced complete information game. In fact, truthful reporting is an ex-post Nash equilibrium of the mediated game, so our solution applies even in settings of incomplete information, and even when player types are arbitrary or worst-case i.e. not drawn from a common prior. We achieve this by giving an efficient differentially private algorithm for computing a Nash equilibrium in such games. The rates of convergence to equilibrium in all of our results are inverse polynomial in the number of players n. We also apply our main results to a multi-dimensional market game. Our results can be viewed as giving, for a rich class of games, a more robust version of the Revelation Principle, in that we work with weaker informational assumptions no common prior, yet provide a stronger solution concept ex-post Nash versus Bayes Nash equilibrium. In comparison to previous work, our main conceptual contribution is showing that weak mediators are a game theoretic object that exist in a wide variety of games --- previously, they were only known to exist in traffic routing games. We also give the first weak mediator that can implement an equilibrium optimizing a linear objective function, rather than implementing a possibly worst-case Nash equilibrium.
Adaptive Parallel Computation of a Grand-Challenge Problem: Prediction of the Path of a Solar-Corona Mass Ejection

One of the ways that the Sun interacts with the Earth is through the solar wind, which is an ionized multi-component fluid that emanates from the Sun and travels radially outward at hundreds of kilometers per second. Solar-wind transients, such as Coronal Mass Ejections (CME's), can be particularly important. In rare cases, CME's have affected the lower atmosphere of the Earth, causing regional power-grid failures. More regularly, CME's pose threats to satellites and spacecraft. Due to the extreme range of temporal and spatial scales involved in solar-wind phenomena, it had previously been impossible to predict CME propagation to Earth with faster-than-real-time, well-resolved calculations. Our team has now developed a highly scalable solution-adaptive scheme for predicting CME propagation. The solution-adaptive technique is an adaptive mesh refinement (AMR) scheme for magneto- hydrodynamic (MHD) calculations. The physical domain is decomposed into three- dimensional blocks, where each block forms a regular grid. In regions of relatively high gradients, blocks are successively refined. Blocks are distributed to processors, with communication between neighboring blocks is handled by asynchronous message passing. The benchmark calculation achieved 212 Gflops on a 1024-processor Cray T3E-1200, with the grid adapting over the course of the calculation from 2048 blocks to 11,729 blocks, where each block was composed of 10x10x10 cells. On a 512-processor Cray T3E-600, our benchmark simulations were performed 16 times faster than real time.
On the Mean-Variance Tradeoff in Option Replication with Transactions Costs

This paper analyzes the tradeoff between cost and risk of discretely rebalanced option hedges in the presence of transactions costs. I present closed form solutions for expected hedging error, transactions costs, and variance of the cash flow from a time-based hedging strategy similar to that analyzed by Leland (1985). Furthermore, I characterize the cost and risk of a move-based hedging strategy without resorting to Monte Carlo simulations. All results are sufficiently general to accommodate the use of a transactions costs adjusted hedging volatility and an asset rate of return that differs from the risk-free rate of return.
Variational ansatz for PT-symmetric quantum mechanics

Abstract A variational calculation of the energy levels of the class of PT -invariant quantum mechanical models described by the non-Hermitian Hamiltonian H=p2−(ix)N with N positive and x complex is presented. The energy levels are determined by finding the stationary points of the functional 〈H〉(a,b,c)≡( ∫ C dx ψ(x)Hψ(x))/( ∫ C dx ψ 2 (x)) , where ψ(x)=(ix) c exp a(ix) b is a three-parameter class of PT -invariant trial wave functions. The integration contour C used to define 〈H〉(a,b,c) lies inside a wedge in the complex-x plane in which the wave function falls off exponentially at infinity. Rather than having a local minimum the functional has a saddle point in the three-parameter (a,b,c)-space. At this saddle point the numerical prediction for the ground-state energy is extremely accurate for a wide range of N. The methods of supersymmetric quantum mechanics are used to determine approximate wave functions and energy eigenvalues of the excited states of this class of non-Hermitian Hamiltonians.
Wage rigidity and disinflation in emerging countries

This paper examines the consequences of rapid disinflation for downward wage rigidities in two emerging countries, Brazil and Uruguay. Although wage rigidities are altered by disinflation, in neither of the two countries does price stability eliminate frictions in wage-setting mechanisms. In a context of individual wage negotiations and weak unions, disinflation in Uruguay puts an end to its history of indexation, but strong resistance to nominal wage cuts emerges. In strongly unionized Brazil, wage indexation is highly persistent, but the introduction of inflation targeting by the Central Bank in 1999 moves the focal point of wage negotiations to expected inflation.
Lattice filters for RLS estimation of a delta operator-based model

A lattice filter algorithm is derived for the recursive least-squares (RLS) estimation of the parameters of the input-output model of a plant, based on the delta-operator formulation. The lattice derivation presented allows a numerically efficient implementation, particularly for large orders. The order-recursive property of the lattices is ideally suited for order determination techniques and applications where the order of the plant may change during operation. An example concerning parameter identification for a fourth-order plant with measurement noise is given. >
Revisiting the incentive to tolerate illegal distribution of software products

Motivated by the recent strategy switch of a large software producer, this paper revisits the trade-offs associated with tolerating illegal distribution of software products. Conventional wisdom is that a higher level of positive network effects justifies a tolerant approach on the part of software producers-because illegal distribution leads to more users, amplifies positive network effects, and creates a greater demand for the legal version. I show that this wisdom does not hold in the context of supporting illegal versions with patches. Patches are used for plugging security vulnerabilities as well as for distributing functionality changes. Software producers have the option of supporting illegal versions with either or both kinds of patches. I find that, even in the presence of strong positive network effects, the least tolerant approach of denying illegal versions both kinds of patches can be optimal.
Flavored Dark Matter: A Review

The current status of flavored dark matter (DM) is reviewed. We discuss the main experimental constraints on models of flavored DM and survey some possible considerations which are relevant for the constructions of models. We then review the application of existing flavor principles to DM, with an emphasis on minimal flavor violation, and discuss implications of flavored DM on collider phenomenology.
Detecting abnormal operating performance: The empirical power and specification of test statistics

This research evaluates methods used in event studies that employ accounting-based measures of operating performance. We examine the choice of an accounting-based performance measure, a statistical test, and a model of expected operating performance. We document the impact of these choices on the test statistics designed to detect abnormal operating performance. We find that commonly used research designs yield test statistics that are misspecified in cases where sample firms have performed either unusually well or poorly. In this sampling situation, the test statistics are only well specified when sample firms are matched to control firms of similar pre-event performance.
Multiframe image point matching and 3-D surface reconstruction

This paper presents two new methods, the Joint Moment Method (JMM) and the Window Variance Method (WVM), for image matching and 3-D object surface reconstruction using multiple perspective views. Like the conventional two-frame correlation method, the JMM and WVM require finding the extrema of 1-D curves, which are proved to theoretically approach a delta function exponentially as the number of frames increases for the JMM and are much sharper than the two-frame correlation function for both the JMM and the WVM. The theoretical findings have been supported by simulations.
Fixed-order compensator design based on frequency-shaped cost functionals

This paper treats the design of fixed order compensators using frequency shaped cost functionals. The formulation is done in an output feedback setting which exploits an observer canonical form to represent the compensator dynamics. The major advantages of the design approach are that the order of the compensator is fixed by the design process, and it is not necessary to realize the frequency shaping dynamics as an integral part of the compensator design. This avoids the two-step approach of full state feedback design followed by the design of an observer, which in the case of a full order observer requires a compensator of order n + nf where n is the order of the plant and nf is the order of the frequency shaping realization. The formulation also precludes the use of direct feedback of the plant output, thus reducing the effect of sensor noise and improving the robustness to high frequency unmodeled dynamics. A structural vibration model describing the fast dynamics of a lightweight flexible arm is used as an example to illustrate the design procedure.
Generalized queries on probabilistic context-free grammars

Probabilistic context-free grammars (PCFGs) provide a simple way to represent a particular class of distributions over sentences in a context-free language. Efficient parsing algorithms for answering particular queries about a PCFG (i.e., calculating the probability of a given sentence, or finding the most likely parse) have been developed and applied to a variety of pattern-recognition problems. We extend the class of queries that can be answered in several ways: (1) allowing missing tokens in a sentence or sentence fragment, (2) supporting queries about intermediate structure, such as the presence of particular nonterminals, and (3) flexible conditioning on a variety of types of evidence. Our method works by constructing a Bayesian network to represent the distribution of parse trees induced by a given PCFG. The network structure mirrors that of the chart in a standard parser, and is generated using a similar dynamic programming approach. We present an algorithm for constructing Bayesian networks from PCFGs, and show how queries or patterns of queries on the network correspond to interesting queries on PCFGs. The network formalism also supports extensions to encode various context sensitivities within the probabilistic dependency structure.
Nonlinear Dynamics and Its Applications in Micro- and Nanoresonators

This review provides a summary of the work completed to date on the nonlinear dynamics of resonant micro- and nanoelectromechanical systems (MEMS/NEMS). This research area, which has been active for approximately a decade, involves the study of nonlinear behaviors arising in small scale, vibratory, mechanical devices that are typically integrated with electronics for use in signal processing, actuation, and sensing applications. The inherent nature of these devices, which includes low damping, desired resonant operation, and the presence of nonlinear potential fields, sets an ideal stage for the appearance of nonlinear behavior, and this allows engineers to beneficially leverage nonlinear dynamics in the course of device design. This work provides an overview of the fundamental research on nonlinear behaviors arising in micro/nanoresonators, including direct and parametric resonances, parametric amplification, impacts, selfexcited oscillations, and collective behaviors, such as localization and synchronization, which arise in coupled resonator arrays. In addition, the work describes the active exploitation of nonlinear dynamics in the development of resonant mass sensors, inertial sensors, and electromechanical signal processing systems. The paper closes with some brief remarks about important ongoing developments in the field.
Bad and worse: neural systems underlying reappraisal of high- and low-intensity negative emotions

One of the most effective strategies for regulating emotional responses is cognitive reappraisal. While prior work has made great strides in characteriz- ing reappraisals neural mechanisms and behavioral outcomes, the key issue of how regulation varies as a function of emotional intensity remains unaddressed. We compared the behavioral and neural correlates of reappraisal of high- and low-intensity emotional responses using functional magnetic resonance imaging (fMRI). We found that successful reappraisal of both high- and low-intensity emotions depends upon recruitment of dorsomedial (dmPFC) as well as left dorsolateral (dlPFC) and ventrolateral (vlPFC) prefrontal cortex. However, reappraisal of high-intensity emotions more strongly activated left dlPFC, and in addition, activated right lateral and dorsomedial PFC regions not recruited by low-intensity reappraisal. No brain regions were more strongly recruited during reappraisal of low when compared with high-intensity emotions. Taken together, these results suggest that reappraisal of high-intensity emotion requires greater cognitive resources as evidenced by quantitative and qualitative differences in prefrontal recruitment. These data have implications for understanding how and when specific PFC systems are needed to regulate different types of emotional responses.
Observational Determinations of the Proton to Electron Mass Ratio in the Early Universe

The values of the fundamental physical constants determine the nature of our universe from the height of mountains on earth to the evolution of the universe over its history. One of these constants is μ = M P / M e the ratio of the proton to electron mass. Astronomical observations provide a determination of this ratio in the early universe through observations of molecular absorption and emission lines in distant objects. Observations of molecular hydrogen in distant damped Lyman Alpha clouds provide a measurement of μ at a time when the universe was only 20% of its present age. To date there is no evidence for a change in μ at the level of 1 part in 10 5 . This limit produces an observational constraint on quintessence theories for the evolution of the universe and Super Symmetric theories of elementary particles.
A Meet in the Middle Attack on Reduced Round Kuznyechik

Kuznyechik is an SPN block cipher that has been recently chosen to be standardized by the Russian federation as a new GOST cipher. The algorithm updates a 128-bit state for nine rounds using a 256-bit key. In this paper, we present a meet-in-the-middle attack on the 5-round reduced cipher. Our attack is based on the differential enumeration approach, where we propose a distinguisher for the middle rounds and match a sequence of state differences at its output. However, the application of the exact approach is not successful on Kuznyechik due to its optimal round diffusion properties. Accordingly, we adopt an equivalent representation for the last round where we can efficiently filter ciphertext pairs and launch the attack in the chosen ciphertext setting. We also utilize partial sequence matching which further reduces the memory and time complexities through relaxing the error probability. The adopted partial sequence matching approach enables successful key recovery by matching parts of the generated sequence instead of the full sequence matching used in the traditional settings of this attack. For the 5-round reduced cipher, the 256-bit master key is recovered with a time complexity of 2, a memory complexity of 2, and a data complexity of 2.
Why Is the Developed World Obese

Obesity has risen dramatically in the past few decades. However, the relative contribution of energy intake and energy expenditure to rising obesity is not known. Moreover, the extent to which social and economic factors tip the energy balance is not well understood. This exploratory study estimates the relative contribution of increased caloric intake and reduced physical activity to obesity in developed countries using two methods of energy accounting. Results show that rising obesity is primarily the result of consuming more calories. We estimate multivariate regression models and use simulation analysis to explore technological and sociodemographic determinants of this dietary excess. Results indicate that the increase in caloric intake is associated with technological innovations as well as changing sociodemographic factors. This review offers useful insights to future research concerned with the etiology of obesity and suggests that obesity-related policies should focus on encouraging lower caloric intake.
Wireless in-building network architecture and protocols

The authors highlight the topology, architecture, and protocols developed for a wireless in-building network based on 18-GHz radio technology. They introduce the requirements of an in-building office environment that involves desktop computing applications and describe a microcellular topology with store-and-forward radio modules that uses time division duplex techniques to organize transmitting and receiving. Unique to the architecture and protocols are methods for coordinating devices with sectorized antennas, for providing high performance in terms of high throughput and low delay, and for compatibility with networking standards. >
Presentations of Rings with Non-Trivial Semidualizing Modules

Let R be a commutative noetherian local ring. A finitely generated R-module C is semidualizing if it is self-orthogonal and \({{\rm Hom}_R(C,C)\cong R}\) . We prove that a Cohen–Macaulay ring R with dualizing module D admits a semidualizing module C satisfying \({R\ncong C \ncong D}\) if and only if it is a homomorphic image of a Gorenstein ring in which the defining ideal decomposes in a cohomologically independent way. This expands on a well-known result of Foxby, Reiten and Sharp saying that R admits a dualizing module if and only if R is Cohen–Macaulay and a homomorphic image of a local Gorenstein ring.
Quantifying the deep convective temperature signal within the tropical tropopause layer (TTL)

Abstract. Dynamics on a vast range of spatial and temporal scales, from individual convective plumes to planetary-scale circulations, play a role in driving the temperature variability in the tropical tropopause layer (TTL). Here, we aim to better quantify the deep convective temperature signal within the TTL using multiple datasets. First, we investigate the link between ozone and temperature in the TTL using the Southern Hemisphere Additional Ozonesondes (SHADOZ) dataset. Low ozone concentrations in the TTL are indicative of deep convective transport from the boundary layer. We confirm the usefulness of ozone as an indicator of deep convection by identifying a typical temperature signal associated with reduced ozone events: an anomalously warm mid to upper troposphere and an anomalously cold upper TTL. We quantify these temperature signals using two diagnostics: (1) the "ozone minimum" diagnostic, which has been used in previous studies and identifies the upper tropospheric minimum ozone concentration as a proxy for the level of main convective outflow; and (2) the "ozone mixing height", which we introduce in order to identify the maximum altitude in a vertical ozone profile up to which reduced ozone concentrations, typical of transport from the boundary layer are observed. Results indicate that the ozone mixing height diagnostic better separates profiles with convective influence than the ozone minimum diagnostic. Next, we collocate deep convective clouds identified by CloudSat 2B-CLDCLASS with temperature profiles based on Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Position System (GPS) radio occultations. We find a robust large-scale deep convective TTL temperature signal, that is persistent in time. However, it is only the convective events that penetrate into the upper half of the TTL that have a significant impact on TTL temperature. A distinct seasonal difference in the spatial scale and the persistence of the temperature signal is identified. Deep-convective cloud top heights are on average found to be well described by the level of neutral buoyancy.
Digital reconstruction of nonlinear beam propagation

We extend the technique of digital holography to the case of propagation through nonlinear media. We experimentally verify the technique by reconstructing nonlinear wave dynamics within a self-defocusing medium and nonlinearly imaging through it.
Hyponormality and subnormality for powers of commuting pairs of subnormal operators

Let H0 (respectively H∞) denote the class of commuting pairs of subnormal operators on Hilbert space (respectively subnormal pairs), and for an integer k⩾1 let Hk denote the class of k-hyponormal pairs in H0. We study the hyponormality and subnormality of powers of pairs in Hk. We first show that if (T1,T2)∈H1, the pair (T12,T2) may fail to be in H1. Conversely, we find a pair (T1,T2)∈H0 such that (T12,T2)∈H1 but (T1,T2)∉H1. Next, we show that there exists a pair (T1,T2)∈H1 such that T1mT2n is subnormal (for all m,n⩾1), but (T1,T2) is not in H∞; this further stretches the gap between the classes H1 and H∞. Finally, we prove that there exists a large class of 2-variable weighted shifts (T1,T2) (namely those pairs in H0 whose cores are of tensor form (cf. Definition 3.4)), for which the subnormality of (T12,T2) and (T1,T22) does imply the subnormality of (T1,T2).
Curve shortening and the topology of closed geodesics on surfaces

We study ?flat knot types? of geodesics on compact surfaces M2. For every flat knot type and any Riemannian metric g we introduce a Conley index associated with the curve shortening flow on the space of immersed curves on M2. We conclude existence of closed geodesics with prescribed flat knot types, provided the associated Conley index is nontrivial.
Students choosing colleges: Understanding the matriculation decision at a highly selective private institution

Abstract This paper provides an econometric analysis of the matriculation decisions made by students accepted to Williams College, one of the nation's most highly selective colleges and universities. Using data for the Williams classes of 2008 through 2012 to estimate a yield model, we find that—conditional on the student applying to and being accepted by Williams—applicant quality as measured by standardized tests, high school GPA and the like, the net price a particular student faces (the sticker price minus institutional financial aid), the applicant's race and geographic origin, plus the student's artistic, athletic and academic interests, are strong predictors of whether or not the student will matriculate.
Something in the water: contaminated drinking water and infant health

This paper provides estimates of the effects of in utero exposure to contaminated drinking water on fetal health. To do this, we examine the universe of birth records and drinking water testing results for the state of New Jersey from 1997 to 2007. Our data enable us to compare outcomes across siblings who were potentially exposed to differing levels of harmful contaminants from drinking water while in utero. We find small effects of drinking water contamination on all children, but large and statistically significant effects on birth weight and gestation of infants born to less educated mothers. We also show that those mothers who were most affected by contamination were the least likely to move between births in response to contamination.