Miracle-dz/UniFAR-FTUs huggingface dataset:
Relationships among transforms, convolutions, and first variations

In this paper, we establish several interesting relationships involving the Fourier-Feynman transform, the convolution product, and the first variation for functionals F on Wiener space of the form F(x)=f(〈α1,x〉,…,〈αn,x〉), (*) where 〈αj,x〉 denotes the Paley-Wiener-Zygmund stochastic integral ∫0Tαj(t)dx(t).
Dificultades para Codificar, Relacionar y Categorizar Problemas Verbales Algebraicos: dos estudios con estudiantes de secundaria y profesores en formación

Solving verbal problems by transfer implies the activation of other, previously solved problems by means of the analogies perceived between these and the ‘target problems’. Two related studies are conducted to analyse what features students focus on to codify problems and to build analogies among them when sorting tasks are proposed. Quantitative and qualitative techniques were used in the analysis. First, we analysed how different science problem characteristics influence secondary students’ task performance. A high proportion of participants were not able to perceive suitable analogies and differences among problems. The second study tried to look for explanations. The Academic level and the Familiarity with the problems topic were significant factors. However, our grade participants, in a pre-service post-grade course to be mathematics teachers, found more difficulties than expected, indicating that some usual instructional assumptions should be reconsidered.
Midinfrared intersubband absorption in wide band gap II-VI ZnxCd1−xSe multiple quantum wells with metastable zincblende MgSe barriers

The authors report the observation of midinfrared intersubband (ISB) absorption in MgSe∕ZnxCd1−xSe multiple quantum wells (MQWs) grown on (001) InP substrates by molecular beam epitaxy. The in situ reflection high energy electron diffraction shows that zincblende MgSe∕ZnxCd1−xSe MQWs can be grown with the introduction of ZnxCd1−xSe spacer layers. For quantum wells with the nominal well width of 11–15 ML (3.2–4.4nm) ISB absorption in the wavelength range of 3.3–4. 9μm is observed. The conduction band offset (CBO) of the MgSe∕ZnxCd1−xSe heterostructure is estimated to be 1.2eV. Using the estimated CBO, the theoretically calculated interband and ISB transition energies agree well with photoluminescence and Fourier-transform infrared spectroscopy measurements. With such a large CBO, ISB transitions in this material system could be extended to the near infrared region.
Piano string modeling: From partial differential equations to digital wave‐guide model

A new class of partial differential equations (PDE) is proposed for transverse vibration in stiff, lossy strings, such as piano strings. While only second‐order in time, it models both frequency‐dependent losses and dispersion effects. By restricting the time‐order to 2, valuable advantages are achieved: First, the frequency‐domain analysis is simplified, making it easy to obtain explicit formulas for dispersion and loss versus frequency; for the same reason, exact bounds on sampling in associated finite‐difference‐schemes (FDS) can be derived. Second, it can be shown that the associated FDS is ‘‘well posed’’ in the sense that it is stable, in the limit, as the sampling period goes to zero. Finally, the new PDE class can be used as a starting point for digital wave‐guide modeling [a digital wave‐guide factors one‐dimensional wave propagation as purely lossless throughout the length of the string, with losses and dispersion lumped in a low‐order digital filter at the string endpoint(s)]. We perform numeric.
Relations Between Spatial Correlations of Rich Clusters of Galaxies

The authors express the N-point rich cluster correlation function in terms of the two-point rich cluster correlation function in a model where rich clusters formed wherever suitably averaged primordial energy density fluctuations are unusually large. The validity of the results is not restricted to regions where the connected (reduced) N-point correlation functions are small compared with unity.
The effective polytropic index in a magnetized plasma

The effective polytropic index γeƒƒ in a magnetized anisotropic plasma is obtained in the frame of one-fluid, double-adiabatic magnetohydrodynamics. The value of γeƒƒ is found to depend on the characteristics of the plasma flow, and on the temperature anisotropy. It is shown that the most probable value of γeƒƒ is 1.4–1.9 at the bow shock, and it may be less than unity in the magnetopause region.
Testing Treatment-Covariate Interaction in a Nonparametric Analysis of Covariance Model

We consider a recently introduced nonparametric model for Analysis of Covariance and derive an asymptotic test for interaction between covariate and treatment. Furthermore, we suggest data depth techniques to obtain joint confidence regions for the covariate effects in this model. The finite sample behavior of the asymptotic method is evaluated in simulations. Application of the procedures is illustrated using an epileptic seizures and chemotherapy data set.
Contralateral cueing effects in the perception of aspirated stop consonants

Backward making has been conjectured to be one possible acoustic factor determining the category boundary for voiceless stop consonants in CV syllables. Recent research from our laboratory has shown that contralateral cues providing timing information about the signal to be detected improved the detectability of monaural tonal signals in backward masking situations, but not in either simultaneous or forward masking situations [Puleo and Pastore, J. Acoust. Soc. Am. 62, S25(A) (1977)]. We therefore employed this technique to investigate the perception of the aspirated stop consonant‐vowel syllable /pa/. Both tonal and noise cues providing timing information to the earphone contralateral to the signal earphone altered performance in the predicted manner. Under certain conditions the Gaussian noise cue also altered the perceived phonetic category from /pa/ to /ta/. [This research was conducted while the author was visiting Haskins Laboratories and was supported by BRS Grant RR‐05596 to Haskins Laboratories. ]
Linear Parameter-varying Control for Active Vibration Isolation Systems with Stiffness Hysteresis

We consider the use of linear parameter-varying methods for the control of stiffness hysteresis in vibration isolation systems. We assume that the hysteresis model is known, and we describe it using a stiffness parameter that takes values in a compact convex set. The proposed parameter-dependent controller is continuously scheduled based on real-time measurements or estimates of the stiffness, and provides guaranteed stability and performance for the full range of stiffness variability. The method is applied to a simplified model of a microgravity vibration isolation system with an umbilical stiffness hysteresis non-linearity. Simulations show that the parameter-varying design is stable in the presence of hysteresis and that the desired isolation performance is achieved over the full range of displacements considered. The results are compared with those obtained with a fixed robust H∞ controller that considers the stiffness variability as uncertainty. We discuss robustness issues and demonstrate the effect of hysteresis model uncertainty in the implementation of the proposed control scheme.
Effects of Very High Pressures on Glass

In contrast to other inorganic solids, glasses may be permanently compacted by application of pressures of the order of 104 to 105 atmospheres. This effect was studied on two simple oxide glasses (SiO2 and B2O3) and several silicate glasses. The effect of compacting was studied by measuring the densities, dimensions, and x‐ray diffraction patterns. A definite threshold pressure is observed in vitreous silica and silicate glasses, under which no effect takes place and above which the collapse takes place readily. Vitreous boric oxide behaves in a different manner, collapsing gradually, starting at the lowest pressures. Vitreous boric oxide exhibits also plastic flow with subsequent strain hardening. X‐ray diffraction measurements performed on vitreous silica and boric oxide indicate that the compacting proceeds on the atomic scale, leaving, however, the short‐range order of the basic structural units unchanged. The density of compacted glass can be restored to the original value by annealing to sufficiently high temperatures. Activation energy of this process was determined in the case of vitreous boric oxide.
The dissociation of diatomic molecules at surfaces

We present an exposition of the various theoretical models currently in use for describing the dynamics of molecular dissociation at surfaces. We begin by outlining the representations of the nuclear and electronic dynamics and how these define the potential energy surfaces for the interactions. Strategies for solving the nuclear motion follow with particular emphasis being paid to a quantum description on the electronic ground state which is in line with experiments employing hyperthermal molecular beams. These can be performed in either a time-dependent or time-independent fashion and both approaches are considered. Following this, the methods that have been developed for treating the dissipative motion as the molecule nears the surface are presented. This is divided into energy loss to the electronic subsystem and to the substrate atomic vibrations. The final part of the review shows how the results of theoretical simulations have been usefully applied to rationalize data obtained from molecular beam scattering experiments.
Bifurcations in Kolmogorov and Taylor-vortex flows

The bifurcation structure of Kolmogorov and Taylor-Vortex flows was computed with the aid of the Recursive Projection Method; see Schroff and Keller [32]. It was shown that RPM significantly improves the convergence of our numerical method while calculating steady state solutions. Moreover we use RPM to detect bifurcation points while continuing along solution branches, and to provide the required augmentation when continuing around a fold, or along a traveling wave branch. The bifurcations to two and three-dimensional solutions from the shear flow solution of Kolmogorov flow are calculated both numerically, by solving an ordinary differential equation, and analytically, using an approximation method. Our results for the two-dimensional bifurcations agree with the work of Meshalkin and Sinai [26]. We also explain how the branches of Kolmogorov flows observed by Platt and Sirovich [29] are connected together, and observe that our solutions have worm like structures even at relatively low Reynolds numbers. Various statistics of our flows are calculated and compare with those from isotropic turbulence calculations. Additionally various solution branches of the Taylor Vortex flow were computed, including spiral vortices. Furthermore, it was discovered that the Wavy Taylor Vortex branches arise from sub-critical Hopf bifurcations, and they undergo a fold close to their bifurcation point.
Threshold Cointegration and the PPP Hypothesis

Self-Exciting Threshold Autoregressive (SETAR) models are a non-linear variant of conventional linear Autoregressive (AR) models. One advantage of SETAR models over conventional AR models lies in its flexible nature in dealing with possible asymmetric behaviour of economic variables. The concept of threshold cointegration implies that the Error Correction Mechanism (ECM) at a particular interval is inactive as a result of adjustment costs, and active when deviations from equilibrium exceed certain thresholds. For instance, the presence of adjustment costs can, in many circumstances, justify the fact that economic agents intervene to recalibrate back to a tolerable limit, as in the case when the benefits of adjustment are superior to its costs. We introduce an approach that accounts for potential asymmetry and we investigate the presence of the relative version of the purchasing power parity (PPP) hypothesis for 14 countries. Based on a threshold cointegration adaptation of the unit root test procedure suggested by Caner & Hansen (2001), we find evidence of an asymmetric adjustment for the relative version of PPP for eight pairs of countries.
Fabrication of a microelectromechanical directional sound sensor with electronic readout using comb fingers

By emulating the hearing organ of the Ormia ochracea fly, a microelectromechanical sound sensor was fabricated which is able to determine the direction of incident sound despite an overall size much smaller than the wavelength of interest. The sensor consists of two wings that are coupled in the middle and attached to the surrounding substrate by two legs. The design incorporated interdigitated comb fingers on the wings and the substrate which enables electrostatic (capacitive) readout. Measured electrical response showed a strong dependence on the direction of incident sound.
Sources and sinks of travelling waves in a single-mode laser

Using the perturbative reduction method, we derive evolution equations for the envelope of the travelling wave solutions of the Maxwell–Bloch equations, immediately above the threshold. Nonlinear transport equations are obtained, the stationary solutions of which are determined analytically. This shows the existence of sink points where two travelling waves merge together, and of light–shadow fronts where a travelling wave is created, coming from the off-state. Two such fronts can yield a very large source structure, especially in periodic patterns, in which the total intensity oscillates. Finally, we show that similar behaviours occur when the density of resonant atoms is so high that local field correction must be taken into account.
Discriminant function between composite hypotheses and related problems

The paper deals with the problem of constructing discriminant functions when the alternative hypotheses are not simple but composite. Such a problem arises when it is intended to identify an individual as belonging to one of two sets, each set consisting of several populations mixed in unknown proportions. A general approach to this problem, using the concepts of decision theory, sufficient statistics and ancillary statistics is given. In particular, when the means of the alternative popublations within a given set are linearly related and the distributions are p variate normal, the discriminant function comes out in a simpler form. It is linear when the dispersion matrices are the same for all the populations and quadratic when the dispersion matrices within sets differ. Methods of estimating the discriminant function from sample date are fully disussed. The fact that in the situations considered one has observations from a mixture of populations within a set does not create any difficulty.
High‐gain observers and linear output regulation for hybrid exosystems

We consider the hybrid output regulation problem for minimum phase linear systems with relative degree greater than one. In the hybrid output regulation problem, an exosystem provides a disturbance or tracking signal that must be matched via an internal model in order to asymptotically regulate the error. This hybrid exosystem is a linear system that experiences periodic jumps. In this context, we build upon previous works in hybrid output regulation by showing how high‐gain observers can successfully overcome the obstacle of high relative degree. In certain scenarios, they can also be used to stabilize the hybrid internal model dynamics through jumps. Copyright © 2013 John Wiley & Sons, Ltd.
Embedding reverse links in a blockchain

Blockchains provide extremely simple certainty looking backward in time because of the way each block contains a hash of its prede-cessor. This is not possible in the same way looking forward in time for various reasons, not the least of which is that when block 𝑁 is created, block 𝑁 + 1, and thus its hash, are unknown. Therefore blockchains rely on more complex mechanisms to establish what the successor of any given block is, and to ensure that alternatives - known as forks - cannot be introduced either close to the time of its creation or long after. These typically rely on chains of dependency and PKIs. In this paper we show how the concept of hooks can create something closely analogous to the usual hash links, only in the other direction. These represent a powerful mechanism to counteract attempts to insert forks from relatively old blocks, and are entirely internal to the blockchain. In understanding hooks we do some detailed combinatorial analysis of the game that good and bad agents play in blockchains, introducing criteria for relatively small collections of agents to make decisions, up to stochastic certainty.
Temporal and Spatial Behavior of Large-Scale Disturbances in Tropical Cloudiness Deduced from Satellite Brightness Data

Abstract The large-scale cloud field in the latitude belt 35°S–35°N is studied using satellite brightness data for the periods May 1967 to October 1967, and November 1967 to Apfil 1968. Time and space-time spectrum and longitude-time section analyses are employed. The cloud field is found to be highly transient and localized, with marked seasonal and regional variations. The variance of cloud activity is remarkably asymmetric about the equator during northern summon. Throughout the year the predominant time scale near 10°N is 5 days. It is associated with two major spatial scales (wavenumbers 10 and 5–6) similar to those of tropospheric easterly waves and the stratospheric Yanai-Maruyama waves, respectively. During the northern winter, pronounced activity near 15°S is associated with wavenumbers 7–15 and a period of 7–12 days. Over the equatorial Indian Ocean eastward-moving disturbances of wavenumber 2 (formally) and period 40 days, and wavenumber 5 and period 9 days, prevail. Well defined space and time.
Information Acquisition and Disclosure in Forecasting Contests

We study price efficiency of analyst forecasts when competing analysts strategically acquire and disclose information in forecasting contests. In acquiring information, analysts face a tradeoff—while more precise information improves their forecast accuracy and the likelihood of winning the contest, it also increases their conditional signal correlation making differentiation to win the contest harder. In equilibrium, analysts cannot make truthful forecasts if contest rewards are sufficiently high. Increasing contest competitiveness, by scaling up contest rewards: generally, encourages information production, but can discourage information acquisition by the weaker analyst to the point of not acquiring information at all; and reduces price efficiency at higher reward levels. Two ex-ante identical analysts can become differently informed and use opposing forecasting strategies. JEL: D82, D83, M41,
Experimental Verification of Inferred Regulatory Interactions of EARLY FLOWERING 3 ( GmELF3-1 ) in Glycine max

Understanding the roles of evening complex (EC) genes in the circadian clock of plants can inform how diurnal transcriptional loops in the clock gene network function to regulate key physiological and developmental events, including flowering transition. Gene regulatory interactions among soybean’s circadian clock and flowering genes were inferred using time-series RNA-seq data and the network inference algorithmic package CausNet. In this study, we seek to clarify the inferred regulatory interactions of the EC gene GmELF3-1. A gene expression analysis using soybean protoplasts as a transient model indicated regulatory roles of GmELF3-1 in expression of selected flowering genes.
A CFD Simulation Study of the Effect of Thermal Conductivity of the Catalyst Bed on Fischer-Tropsch Synthesis

One of the most challenging technical barriers for fixed bed Fischer-Tropsch (FT) reactors is the formation of a hot spot in the catalyst bed because of the tremendous release of reaction heat. Increasing the thermal conductivity of the catalyst bed is a direct and efficient solution to solve this problem. In this work, Computational Fluid Dynamics (CFD) simulations were carried out to study the effect of the thermal conductivity of a catalyst bed on the Fischer-Tropsch synthesis (FTS) fixed bed reactor. A reasonable constraint was defined for the temperature rise in the catalyst bed, in order to ensure system safety and stability of the catalyst for long-term operation. The catalyst activity and space velocity (SV) were modified in each simulation experiment to ensure the maximum temperature in the catalyst bed did not exceed the temperature rise constraint. The potential maximum productivity of the specific catalyst bed was then predicted and the optimized catalyst activity and SV were obtained, which provided valuable guidance for practical FTS applications. The results showed that by applying a catalyst bed with higher thermal conductivity, better temperature control of the system was achieved, and a higher FTS reaction rate in the catalyst was ensured, which resulted in higher
Sdobnov LASER SPECKLE CONTRAST IMAGING FOR FUNCTIONAL VISUALIZATION

Laser speckle contrast imaging is a modern technique uniquely suited for the full-field, noninvasive measurement of the motion of particles within randomly inhomogeneous highly scattering and absorbing media, including biological tissues. This technique is based on illuminating the medium with a coherent laser light, detecting the arising speckle pattern and further statistical analysis of the speckle pattern fluctuations caused by the motion of the scattering particles in the observed medium. Despite the active use of laser speckle contrast imaging for biomedical applications, this technique suffers from several issues complicating the understanding of obtained speckle contrast data. The present work is aimed at the investigation of limitations, improving, and discovering new potentials of currently existing methods of laser speckle contrast imaging. In particular, the influence of effects of non-ergodicity on the results of speckle contrast analysis was investigated using the phantom and animal models. It was shown that the presence of a thin static layer above the dynamic layer does not introduce significant errors in speckle contrast calculation. The simple approach for the adjustment of speckle contrast values in different types of brain vasculature during transcranial visualisation was introduced. For the first time, the protocol for the monitoring of skin acute vascular permeability reaction in response to simultaneous application of tree different chemical substances has been described. Moreover, in a new approach, the optical setup combining a hyperspectral camera and multi-wavelength light source was implemented for the depth-resolved blood flow and perfusion assessment. The proposed technique was applied for skin perfusion monitoring. Finally, the unprecedented use of laser speckle contrast imaging was introduced for handwriting pressure and kinematics evaluation.
Water in Olive Oil Surfactantless Microemulsions as Medium for CdS Nanoparticles Synthesis

A simple chemical route using ternary 1-butanol/olive/water microemulsion systems without surfactant has been developed to synthesize spherical CdS nanoparticles with an average diameter of ca. 45 nm. The CdS nanoparticles were investigated by transmission electron microscopy (TEM), UV-VIS optical absorption spectrum and Fourier transform infrared (FTIR) spectroscopy measurements. By comparision with previous work, the present work confirmed the effective role of the surfactant in formation nanoparticles.
Accurate and efﬁcient LDU decomposition of almost diagonally dominant Z-matrices

For a class of n × n nonsingular almost row diagonally dominant Z -matrices and given adequate parameters, an efﬁcient method to compute its LDU decomposition with high relative accuracy is provided. It adds an additional cost of O ( n 2 ) elementary operations over the computational cost of Gaussian elimination. Numerical examples illustrate that the obtained LDU decompositions are rank revealing, and comparisons with alternative procedures are included