Miracle-dz/UniFAR-FTUs huggingface dataset:
Large R-charge operators in N =4 super Yang-Mills and their gravity duals

Operators in N = 4 super Yang-Mills theory with an R-charge of O(N) are dual to backgrounds which are asymtotically AdS5×S. In this thesis we develop efficient techniques that allow the computation of correlation functions in these backgrounds. We find that (i) contractions between fields in the string words and fields in the operator creating the background are the field theory accounting of the new geometry, (ii) correlation functions of probes in these backgrounds are given by the free field theory contractions but with rescaled propagators and (iii) in these backgrounds there are no open string excitations with their special end point interactions; we have only closed string excitations. Furthermore, these correlation functions are not well approximated by the planar limit. The non-planar diagrams, which in the bulk spacetime correspond to string loop corrections, are enhanced by huge combinatorial factors. We show how these loop corrections can be resummed. As a typical example of our results, in the half-BPS background of M maximal giant gravitons we find the usual 1/N expansion is replaced by a 1/(M +N) expansion. Further, we find that there is a simple exact relationship between amplitudes computed in the trivial background and amplitudes computed in the background of M maximal giant gravitons. We also find strong evidence for the BMN-type sectors suggested in arXiv:0801.4457. The problem of computing the anomalous dimensions of (nearly) half-BPS operators with a large R-charge is reduced to the problem of diagonalizing a Cuntz oscillator chain. Due to the large dimension of the operators we consider, non-planar corrections must be summed to correctly construct the Cuntz oscillator dynamics. These non-planar corrections do not represent quantum corrections in the dual gravitational theory, but rather, they account for the backreaction from the heavy operator whose dimension we study. Non-planar corrections accounting for quantum corrections seem to spoil integrability, in general. It is interesting to ask if non-planar corrections that account for the backreaction also spoil integrability. We find a limit in which our Cuntz chain continues to admit extra conserved charges suggesting that integrability might survive.
Electron Properties and Coulomb Collisions in the Solar Wind at 1 AU: Wind Observations

The question of what controls the electron properties in the solar wind has been the subject of several extensive analyses over the past 20 years. We analyze here the electron properties of the solar wind observed by the Wind satellite at 1 AU in the ecliptic plane, during 50 days close to the last minimum of solar activity. The electron temperature anisotropy Te∥/Te⊥, which seems to depend on the wind speed Vsw, the density Np, the heliomagnetic latitude λm, or the time, actually depends mainly on the Coulomb collisions. The collisional age Ae is the number of transverse collisions suffered by a thermal electron during the expansion of the wind over the scale of the density gradient. The Ae depends on Vsw, on Np, and thus on λm; it also depends on the time because it changes strongly at the crossing of a stream interface. We show that Te∥/Te⊥ is strongly correlated with 1/Ae. The effect of Coulomb collisions on the electron heat flux are also investigated. We find that the total electron heat flux Qe displays an upper bound that is inversely proportional to the collisional age, in favor of a regulation of the heat flux by Coulomb collisions. The observed heat flux is then compared to the collisional heat flux of the classical Spitzer-Härm (SH) theory. Although earlier observations have shown that the electron heat flux in the solar wind at 1 AU is well below the values given by the SH theory, we find that the observed heat flux reaches the SH limit for the lowest values of the electron mean free paths. The Coulomb collisions thus seem to play a part in the regulation of the electron heat flux in the solar wind.
D-stability bound analysis for discrete multiparameter singularly perturbed systems

The D-stability (i.e., the stability in the sense that all the poles of a system are lying inside the disk D(/spl alpha/,r)) problem for discrete multiparameter singularly perturbed systems is considered in this brief. A two-stage method is first developed to analyze the stability relationship between the discrete multiparameter singularly perturbed systems and their corresponding reduced systems. An upper bound of the singular perturbation parameters is then derived such that the D-stability of the reduced systems implies that of the original systems, provided that the singular perturbation parameters are small enough to be within this bound. This fact enables us to investigate D-stability of the original systems by establishing that of their corresponding reduced systems.
Measuring Differentials in Communication Research: Issues With Multicollinearity in Three Methods

Models of communication processes sometimes require the computation of the difference between two variables. For example, information insufficiency is the difference between what people know and what they think they need to know about an issue, and it can motivate information seeking and processing. Common methods that compute this differential may bias model estimates as a function of the correlation between the differentiated variables and other variables in the model. This article describes the general form of Cohen and Cohen's (1983) analysis of partial variance for computing differentials and analyzes simulated data to contrast that method with two alternative methods. The discussion recommends the use of the general form of the Cohen and Cohen method in other areas of communication research, such as studies of third-person perception.
Resonant interactions between two trains of gravity waves

In a previous paper, Phillips (1960) showed that two or three trains of gravity waves may interact so as to produce a fourth (tertiary) wave whose wave-number is different from any of three primary wave-numbers k1, k2, k3, and whose amplitude grows in time. Such resonant interactions may produce an appreciable modification of the spectrum of ocean waves within a few hours. In this paper, by a slightly different method, the interaction is calculated in detail for the simplest possible case: when two of the three primary wave-numbers are equal (k3 = k1). It is found that, when k1 and k2 are parallel or antiparallel, the interaction vanishes unless k1 = k2. Generally, if θ denotes the angle between k1 and k2, the rate of growth of the tertiary wave with time is a maximum when θ [eDot ] 17°; the rate of growth with horizontal distance is a maximum when θ [eDot ] 24°. The calculations show that it should be possible to detect the tertiary wave in the laboratory.
Competing Species Superprocesses with Infinite Variance

We study pairs of interacting measure-valued branching processes (superprocesses) with alpha-stable migration and $(1+\beta)$-branching mechanism. The interaction is realized via some killing procedure. The collision local time for such processes is constructed as a limit of approximating collision local times. For certain dimensions this convergence holds uniformly over all pairs of such interacting superprocesses. We use this uniformity to prove existence of a solution to a competing species martingale problem under a natural dimension restriction. The competing species model describes the evolution of two populations where individuals of different types may kill each other if they collide. In the case of Brownian migration and finite variance branching, the model was introduced by Evans and Perkins (1994). The fact that now the branching mechanism does not have finite variance requires the development of new methods for handling the collision local time which we believe are of some independent interest.
Modeling Heterogeneity of Latent Growth Depending on Initial Status

In this article, a heterogeneous latent growth curve model for modeling heterogeneity of growth rates is proposed. The suggested model is an extension of a conventional growth curve model and a complementary tool to mixed growth modeling. It allows the modeling of heterogeneity of growth rates as a continuous function of latent initial status and time-invariant covariates. A quasi-ML parameter estimation method and a likelihood-ratio test for heterogeneity of growth is developed, and the new methodology is applied to an empirical example on math achievement data. The example illustrates that the proposed model gives more accurate confidence intervals for the prediction of future math achievement than a conventional growth curve model and identifies the subgroup of subjects which show the most homogeneous growth.
Spectral Analysis and Time Series

Preface. Preface to Volume 2. Contents of Volume 2. List of Main Notation. Basic Concepts. Elements of Probability Theory. Stationary Random Processes. Spectral Analysis. Estimation in the Time Domain. Estimation in the Frequency Domain. Spectral Analysis in Practice. Analysis of Processes with Mixed Spectra.
Equivalence relations between learnability, output-dissipativity and strict positive realness

This paper was originally motivated by aiming at explicating why a simple iterative learning control scheme for complicated robot dynamics with strong non-linearities works well in acquiring any given desired motion over a finite or infinite time duration or any periodic motion. To gain a physical insight into the problem, a class of linear dynamical systems with specified input and output of the same dimension is treated by defining two properties: output-dissipativity and learnability. It is then shown that the former implies the latter and furthermore, for a class of linear systems with single input and single output, they are equivalent to each other and each of them is also equivalent to strict positive realness of input-output transfer function. For a class of MIMO (multiple inputs and multiple outputs) systems, it is possible to prove that each of these properties is equivalent to strict positive realness of the input-output transfer function matrix if it is strictly proper or otherwise its direct term from input to output satisfies an extra condtion.
Parallel Computational Algorithms for the Kinematics and Dynamics of Planar and Spatial Parallel Manipulators

This paper introduces a novel approach for the computation of the inverse dynamics of parallel manipulators. It is shown that, for this type of manipulator, the inverse kinematics and the inverse dynamics procedures can be easily parallelized. The result is a closed-form efficient algorithm using n processors, where n is the number of kinematic chains connecting the base to the end-effector. The dynamics computations are based on the Newton-Euler formalism. The parallel algorithm arises from a judicious choice of the coordinate frames attached to each of the legs, which allows the exploitation of the parallel nature of the mechanism itself. Examples of the application of the algorithm to a planar three-degree-of-freedom parallel manipulator and to a spatial six-degree-of-freedom parallel manipulator are presented.
Phonon backscattering and thermal conductivity suppression in sawtooth nanowires

The effect of surface roughness on phonon transport in a nanowire has often been described by treating the surface as flat with a specularity parameter (p) in the range between 0 and 1. A lower thermal conductivity limit is approached at p=0 for diffuse surface. It is demonstrated here by Monte Carlo simulation that sawtooth roughness on a nanowire can cause phonon backscattering and suppress the thermal conductivity below the diffuse surface limit. The backscattering effect can be accounted for only by a negative p if the detail of the surface roughness is ignored.
System characterization of positive real conditions

Necessary and sufficient conditions for positive realness in terms of state space matrices are presented under the assumption of complete controllability and complete observability of square systems with independent inputs. As an alternative to the positive real lemma and to the s-domain inequalities, these conditions provide a recursive algorithm for testing positive realness which results in a set of simple algebraic conditions. By relating the positive real property to the associated variational problem, the authors outline a unified derivation of necessary and sufficient conditions for optimality of both singular and nonsingular problems. <<ETX>>
New view of quark and lepton mass hierarchy

The hierarchical structure of realistic quark and lepton masses is investigated on the basis of a three-family model, where masses and mixings of the first- and second-generation quarks are successfully described by lepton masses only. An excellent prediction m/sub tau/ = 1.7866 GeV is obtained from the input data m/sub e/ and m/sub . mu. / only.
Longitudinal waves in a perpendicular collisionless plasma shock: I. Cold ions

This paper considers electrostatic waves in a Vlasov plasma of unmagnetized ions and magnetized, Maxwellian electrons. The linear dispersion relation is derived for waves in a perpendicular shock such that the most important sources of instability are the E × B and ∇B electron drifts. For the case of cold ions, propagation perpendicular to the applied magnetic field, and the E × B drift alone, a numerical analysis of frequency vs. wave-number is presented. The effects of the ∇B drift are also considered, and it is shown that the maximum growth rate can be larger than the maximum growth rate for the zero magnetic field ion acoustic instabifity under comparable conditions.
A Laboratory Model of Urban Street-Canyon Flows

Abstract A circulating water channel is constructed to examine urban street-canyon flow. In the cases of an even-notch street canyon in which model buildings on both sides of the street have equal heights, one vortex is observed in model canyons with aspect ratios of 1 and 1.5, and two counterrotating vortices are observed in canyons with aspect ratios of 2, 2.4, and 3. In all of the even-notch cases, the center of the vortex (or the upper vortex) is located slightly downstream of the canyon center, and the downward motion downstream is stronger than the upward motion upstream. The magnitudes of the maximum updraft and downdraft are almost independent of the aspect ratio. In the case of a stepup notch, one vortex is observed in the canyon. In the case of a stepdown notch, two counterrotating vortices are observed. The upper vortex resembles to some extent an isolated roughness flow, and the lower vortex is characterized by a skimming flow. It is shown that the results of the water-channel experiments are .
Asymmetric magnetospheric compressions and expansions in response to impact of inclined interplanetary shock

We use global MHD simulations to model the magnetospheric response to an inclined shock that first strikes the duskside magnetosphere. The simulations predict several phenomena related specifically to the inclined shocks. The magnetospheric compression on the duskside exceeds that on the dawnside, and the geocentric distance to the dusk magnetopause varies in a simple step‐like form. The compression on the dawnside is preceded and followed by expansions. For a moderately strong shock, the expansion magnitude reaches several RE behind the terminator plane. The magnetopause and cross‐tail currents in the magnetotail are significantly deformed during and after the shock passage. The position of the magnetotail magnetopause moves by more than 10 RE. This asymmetric magnetopause deformation is mainly related to a strong |Vy| downstream from the inclined shock. The magnetospheric expansion results in a decrease in the horizontal magnetic field at low‐latitude stations, as confirmed by observations.
Symmetric quantile averages and related estimators

SUMMARY The average of two complementary order statistics is termed a symmetric quantile average. In addition to having quite good efficiency, robustness and computational properties, exact nonparametric confidence intervals for location can be derived from it. A related type of estimator called a combined quantile average is introduced; it is slightly more difficult to compute than the symmetric quantile average, but can have better efficiency and robustness properties. In fact the recommended form of combined quantile average is comparable for robustness and normal efficiency with the 15% trimmed mean, but in addition it leads, like symmetric quantile averages, to the definition of exact nonparametric confidence intervals.
A study of mathematical programmingmethods for structural optimization. Part II: Numerical results

Various mathematical programming methods for structural optimization are studied. In a companion paper, these methods have been studied based on certain theoretical considerations. In this paper, the methods are studied based on solving a set of test problems. The methods that are studied include recursive QP, feasible directions, gradient projection, SUMT and multiplier methods. Various computer codes have been developed, and are studied together with some existing programs such as CONMIN and OPTDYN. The test problems considered have 3–47 design variables and 3–252 constraints. The evaluation criteria consist of studying the accuracy, reliability and efficiency of a code. It turns out that globally convergent algorithms (multiplier methods, in particular) are very reliable but not efficient. Primal algorithms (like CONMIN), which are not proved to be globally convergent, are efficient but not reliable.
On transition to chaos in two-dimensional channel flow symmetrically driven by accelerating walls

We study theoretically the flow of a viscous incompressible fluid in a parallel-walled channel: the flow is driven by uniform steady suction through the porous and accelerating walls of the channel. Previous authors have discussed special cases of such flows, confining attention to flows which are symmetric, steady and two-dimensional; a similarity form of solution is assumed, as used by Berman and originally due to Hiemenz, to reduce the Navier–Stokes equations to a nonlinear ordinary differential equation. We generalize their work by considering asymmetric flows, unsteady flows and three-dimensional perturbations. By use of numerical calculations, matched asymptotic expansions for large values of the Reynolds number, both positive and negative, and the theory of dynamical systems we find many more exact solutions of the Navier–Stokes equations, examine their stability and interpret them; although much of the theory is for the general case, most of the numerical calculations are for the case of zero suction. In particular we show that most of the previously found steady solutions are unstable to antisymmetric two-dimensional disturbances. This leads to a pitchfork bifurcation, stable asymmetric steady solutions, a Hopf bifurcation, stable time-periodic solutions, stable quasi-periodic solutions and chaos in succession as the Reynolds number increases from zero, and a pitchfork bifurcation, stable asymmetric steady solutions, a Hopf bifurcation, periodic solutions, chaos via period doubling, other periodic solutions and chaos in succession as the Reynolds number decreases from zero.
Boiling Augmentation with Micro/Nanostructured Surfaces: Current Status and Research Outlook

Advances in the development of micro- and nanostructured surfaces have enabled tremendous progress in delineation of mechanisms in boiling heat transfer and have propelled the rapid enhancement of heat transfer rates. This area of research is poised to make great strides toward tailoring surface features to produce dramatically improved thermal performance. A workshop was held in April 2013 to provide a review of the current state-of-the-art and to develop near-term and long-term goals for the boiling augmentation community. A brief historical perspective and primary findings are presented in this article. Though impressive gains have been made in enhancement of boiling heat transport, there still remain several unknowns such as the mechanisms that affect critical heat flux and optimization of surfaces for boiling heat transport. The promise of improved spatial resolution of optical techniques should improve knowledge of near-surface mechanisms. Standardization of experimental test sections and procedures has emerged as a critical issue that needs to be addressed immediately.
Does chaos work better than noise

Chaos and random signals share the property of long term unpredictable irregular behavior and broad band spectrum. The aim of this paper is not to distinguish between random and chaotic dynamics, nor to show the use of chaos, but to focus attention on how chaos and noise help order to arise from disorder It means to investigate the effect of the introduction of either deterministic chaotic or random sequences in different types of phenomena. In particular the results related to different applications, self-organization in arrays of locally coupled systems in which a chaotic dissymmetry is present, chaos driven optimization strategies, pattern formation in Drosophila embryos and some new topics on game theory are treated with the aim to investigate the subject: "does chaos work better than noise? ".
Test results of SeCRETS, a stability experiment about segregated copper in CICC

Two Nb/sub 3/Sn cable-in-conduit conductors have been manufactured with identical non-Cu cross sections and the stabilizer either included in the Nb/sub 3/Sn composite or partly segregated as copper wires. The two conductors are series connected and wound as a bifilar, single layer solenoid, assembled in the high field bore (11 T) of the SULTAN test facility. Beside the DC and AC losses characterization, the key tests include stability under pulsed transversal field (dB/dt up to 180 T/s), at DC operating current up to 12 kA. The results show that strong, transverse field transients can be withstood by both conductors with small temperature margin. Cost reduction measures for fusion conductors are discussed.
A Multivariate Variance Gamma Model for Financial Applications

In this paper we subordinate a multivariate Brownian motion with independent components by a multivariate gamma subordinator. The resulting process is a generalization of the bivariate variance gamma process proposed by Madan and Seneta [7], mentioned in Cont and Tankov [4] and calibrated in Luciano and Schoutens [5] as a price process. Our main contribution here is to introduce a multivariate subordinator with gamma margins. We investigate the process, determine its Levy triplet and analyze its dependence structure. At the end we propose an exponential Levy price model.
Off‐Axis Particles in Coulter Type Counters

The resistance increase due to a centered sphere in a tube traversed by an ideal fluid or electric current is tabulated in Phys. Fluids 7, 633 (1964). A lower limit for off‐axis spheres is also known. This note gives an off‐axis upper limit theory and a numerical table which should be useful in sizing particles by the Coulter counter method.
Towards an emerging understanding of non-locality phenomena and non-local transport

In this paper, recent progress on experimental analysis and theoretical models for non-local transport (non-Fickian fluxes in real space) is reviewed. The non-locality in the heat and momentum transport observed in the plasma, the departures from linear flux-gradient proportionality, and externally triggered non-local transport phenomena are described in both L-mode and improved-mode plasmas. Ongoing evaluation of ‘fast front’ and ‘intrinsically non-local’ models, and their success in comparisons with experimental data, are discussed