Miracle-dz/UniFAR-FTUs huggingface dataset:
Do symmetrical letter pairs affect readability? A cross-linguistic examination of writing systems with specific reference to the runes

Our everyday experience shows that we have problems in recognizing objects which only differ in their symmetry properties (street signs with two arrows in different directions or mathematical signs such as 〈 and 〉). Perception is closely correlated with an inner comparison: the perceived object with its surrounding, the perceived object with former experience and so on. The brain has evolved different constancy abilities (e.g. colour constancy) and one of them is object constancy. This object constancy makes it possible to perceive an object regardless of its orientation in space. Symmetric letter pairs with different sound representations (such as 〈b〉 and 〈d〉) are, due to object constancy, typically identified as one object. This deficiency of distinctiveness should affect their readability. The above hypothesis was examined in many scripts. The result was that mature scripts (which usually developed for a long time) avoid these symmetric letter pairs (called extrinsic symmetry) by adding distinctive features such as serifs or different stroke thickness. On the other hand, if a writer is allowed to invent letter shapes freely, he makes use of extrinsic symmetrical letter pairs. This is supposed to have aesthetic reasons — letters are often perceived as a standing object or even as a “body” on a plane. It is therefore possible to statistically separate mature scripts which show up no extrinsic symmetry from invented scripts full of extrinsic symmetry. The runes are a writing system which does not quite fit in this widely proved distinction. They have developed from the Latin writing system (or a close relative of it) and have therefore inherited the avoidance of extrinsic symmetry. The reduction of the character set from 24 signs in the Old Futhark to 16 characters in the Younger Futhark is accompanied by a simplification of runic signs. During this period the runes develop a high degree of extrinsic symmetry. Moreover, the letter shapes are often related to different sound representations. These irregularities in usage may be caused by interference from the Latin writing system. The resulting lesser readability could have been one reason for the decline of the runes. This paper shows in many figures and graphs how symmetry emerges and under what circumstances it is used to create new letter shapes.
A study on biological effects of low-intensity millimeter waves

Resonance-like biological effects of millimeter-wave radiation at frequencies of approximately 42 GHz on the growth rate of E. coli and on DNA have been reported in several scientific publications. In order to explore these nonthermal effects, we have measured the growth rate and the absorption spectrum of E. coli, irradiated by millimeter waves in the frequency range from 41 to 43 GHz. In addition, the effect of this radiation on DNA was studied by measuring plasmid transformation efficiency. Both the growth rate variations with varying frequency and the variations in the result of the plasmid transformation efficiency experiments were found to be statistically insignificant. Resonance-like absorption features observed in the absorption spectrum of E. coli were identified as modes generated in the millimeter-wave system, when the sample was inserted. The experimental results indicate that resonance effects are unlikely in this particular frequency range.
Asteroseismology of the β Cephei star 12 (DD) Lacertae : photometric observations, pulsational frequency analysis and mode identification

We report a multisite photometric campaign for the beta Cephei star 12 Lacertae. 750 h of high-quality differential photoelectric Str�mgren, Johnson and Geneva time-series photometry were obtained with nine telescopes during 190 nights. Our frequency analysis results in the detection of 23 sinusoidal signals in the light curves. Ten of those correspond to independent pulsation modes, and the remainder are combination frequencies. We find some slow aperiodic variability such as that seemingly present in several beta Cephei stars. We perform mode identification from our colour photometry, derive the spherical degree l for the five strongest modes unambiguously and provide constraints on l for the weaker modes. We find a mixture of modes of 0 <=l<= 4. In particular, we prove that the previously suspected rotationally split triplet within the modes of 12 Lac consists of modes of different l their equal frequency splitting must thus be accidental. One of the periodic signals we detected in the light curves is argued to be a linearly stable mode excited to visible amplitude by non-linear mode coupling via a 2:1 resonance. We also find a low-frequency signal in the light variations whose physical nature is unclear; it could be a parent or daughter mode resonantly coupled. The remaining combination frequencies are consistent with simple light-curve distortions. The range of excited pulsation frequencies of 12 Lac may be sufficiently large that it cannot be reproduced by standard models. We suspect that the star has a larger metal abundance in the pulsational driving zone, a hypothesis also capable of explaining the presence of beta Cephei stars in the Large Magellanic Cloud.
The reflection of a plane shock wave over a double wedge

An analysis is presented of the shock-wave configurations which will occur when a plane shock is incident on a double wedge for which the second wedge may have a greater (concave case) or a smaller (convex case) inclination than the first wedge. It is shown that seven different reflection processes may be expected depending on the Mach number of the incidnet shock Mi and the two wedge angles θ1w and θ2w. These processes may be defined by seven regiouns in the (θ1w,θ2w)-plane, for a given value of Mi. Each of the seven processes has been verified by sequences of shadowgraph and schlieren photographs. A shock-polar analysis of each of the seven processes has provided infomation about the pressure changes and the wave structures which develop immediately behind the main reflections along the wedge surfaces. These wave structures have been verified experimentally, and two types have been observed; one normal to the reflecting surface, and the other in the form of a regular reflection. The criteria to determine which of thses configurations will occur have not yet been established. It is believed that the present study will be of value in predicting the loading of shock waves on structures, and may lead to a better understanding of shock reflections form concave and convex cylindrical surfaces.
Triggered star formation in Orion cometary clouds? I. The case of L1616

We present new 1.2 mm continuum maps and near- and mid-infrared images of the cometary cloud L1616 located to the west of the Orion OB associations and apparently shaped by the winds and radiation coming from the massive, hot stars in the OB association. The new data reveal evidence for ongoing star formation in the cloud in addition to the known cluster of somewhat more evolved stars illuminating the NGC 1788 reflection nebula in the head of the cometary cloud. The 1.2 mm survey reveals a tight group of dust continuum sources, the brightest of which is seen to drive a powerful near-infrared H2 jet, apparently a very young protostar of Class 0 type. The location of the newly discovered protostar with respect to the older cluster and the direction towards the OB association suggests an age sequence due to a wave of star formation driven through the cloud and triggered by the impact of the nearby OB association: the older generation of stars is located on the side of the cloud directly facing the OB association, whereas a new generation of star formation takes place deeper within the cloud.
The Livsic Cocycle Equation for Compact Lie Group Extensions of Hyperbolic Systems

In this article we extend well‐known results of Livsic on the regularity of measurable solutions to the cocycle equation. Livsic proved a regularity result for real valued cocycles, but for compact Lie group valued cocycles his result was restricted to coboundaries (that is, trivial or constant cocycles). In this article we prove the complete result.
Faraday chiral media revisited. I. Fields and sources

Faraday chiral media, previously conceptualized as chiroplasmas or chiroferrites, are envisioned to combine the effects of Faraday rotation and chirality. Electromagnetic field representations for arbitrary sources are derived after the previous correct characterization of the constitutive relations of such media. The scalar Hertz potential (SHP) technique is employed and its applicability is thoroughly investigated. In particular, it is shown that all field components can be derived from one scalar Green function (plus so-called auxiliary source potentials) in source problems, whereas one scalar superpotential suffices for source-free problems. Expressions pertaining to radiation from electric and magnetic dipole sources are presented in a simple and compact form. Further generalizations of the results and the actual realizability of Faraday chiral media are discussed.
Improved many-electron wavefunctions from plasmon normal modes

We investigate an alternative approach to the connection between plasmons and the ground-state wavefunction of many-electron systems, starting with a classical plasmon Hamiltonian. We obtain a prescription for the part of the wavefunction which determines the long-ranged electron–electron correlations; we then show how this prescription can be used to construct improved trial wavefunctions for use in quantum Monte Carlo simulations. Using the quasi-2D electron gas as a test system, we construct a trial wavefunction of the Slater–Jastrow form, combining mean-field single-electron orbitals with short-ranged and plasmon-derived long-ranged correlations. Variational quantum Monte Carlo calculations show that the new wavefunction reduces the expectation value of the energy, but the short-ranged correlations are more important than the plasmon-derived ones. Finally, we present a computationally efficient Jastrow factor, which we recommend for future simulations.
The effects of horizontal diffusion on baroclinic development in a spectral model

Linear and non-linear effects on baroclinic development of linear horizontal diffusion of the form K▽2q, where q is an integer and k, in general, a constant, are investigated using a spectral model and a climatological wintertime northern hemisphere basic state. An eigenvalue approach shows the greatest linear sensitivity to the diffusion to be in the high zonal wavenumbers (m > 12) which, in the absence of diffusion or with the more scale-selective formulations (large q), are more unstable than the intermediate wavenumbers (m = 7–9). The ▽4 diffusion with a decay time scale of 6 h on the shortest retained scale, which has traditionally been used in our model, is shown to affect significantly the linear stability of almost all wavenumbers, whereas the more scale-selective formulations have only a very small effect on m < 12. Without dissipation, integrations exhibit grossly physically unrealistic features after about nine days even with very high resolution, indicating the crucial role played by dissipation in non-linear baroclinic development. Non-linear integrations with dissipation show great sensitivity to the formulation used. Typically about three times more energy is converted from potential to kinetic with a ▽6 than with a ▽4 diffusion having a similar decay time scale on the smallest retained spatial scale. It appears that as the dissipation time scale on the large spatial scales is increased while retaining sufficiently short time scales near the truncation limit to prevent the accumulation of energy there, so the amount of potential to kinetic energy conversion approaches a limiting value equal to about five times the energy conversion with the ▽4 diffusion. In the limiting case the amount of energy lost to dissipation is equivalent to about 45% of that converted from potential to kinetic energy, again emphasizing the crucial role played by dissipation. It is found that if the decay time scale on the short spatial scales is too long then the integrations exhibit large truncation dependency. This provides a criterion for judging the suitability of a particular choice of dissipation, which might have quite general applicability.
FINANCIAL CALCULUS: AN INTRODUCTION TO DERIVATIVE PRICING

“Notoriously, works on mathematical finance can be precise, and they can be comprehensible. Sadly, as Dr. Johnson might have put it, the ones which are precise are not necessarily comprehensible, and those comprehensible are not necessarily precise. ” So starts the preface to Baxter and Rennie's recent treatise on financial calculus. The book attempts to give an introduction to modern continuous time finance in a precise and comprehensible fashion. Does it succeed? Yes, it is a very clear and precise little (233 pages) book, although the claim that the book is accessible to a reader with only “some knowledge of (classical) differential calculus and experience with symbolic notation” is exaggerated. Such a reader would find the material hard going indeed.
Comparative analysis of SPOT, Landsat, MODIS, and AVHRR normalized difference vegetation index data on the estimation of leaf area index in a mixed grassland ecosystem

Abstract Many grassland studies have depended on or are currently depending on the Landsat series of satellite sensors for monitoring work. However, given the identified gaps in Landsat data, alternatives to Landsat imagery need to be tested in an operational environment. In this study, normalized difference vegetation index (NDVI) values are derived from a Système Pour l'Observation de la Terre (SPOT), Moderate Resolution Imaging Spectroradiometer (MODIS), and Advanced Very High Resolution Radiometer (AVHRR) image and compared to the NDVI values from a Landsat image for LAI estimation in a semi-arid heterogeneous grassland. Results indicate a high agreement between Landsat and SPOT data with R 2 over 85% at all buffer levels (100, 250, and 1000 m), and a significant but lower agreement between MODIS and Landsat with R 2 around 28% at 250 m buffer level to 37% at 100 m buffer level. Based on in situ measurements of LAI in 22 homogeneous sites, the relationships established between LAI and NDVI show that SPOT and Landsat could predict LAI with acceptable accuracy, but MODIS and AVHRR cannot quantify the spatial variation in LAI measurements. Data fusion or blending techniques that combine the spectral information of high spatial/low temporal resolution data with low spatial/high temporal resolution data may be considered to study semi-arid heterogeneous grasslands.
A simple formula for dynamic spherical cavity expansion in a compressible elastic perfectly plastic material with large deformations

Simple analytical expressions are obtained for the contact pressure applied to a spherical cavity that is expanding with constant velocity in an infinite compressible elastic perfectly plastic material with large deformations. The solution is obtained by using the kinematics of isochoric flow with a modified value of the shear modulus and with a physical boundary condition on the radial stress at the location of the precursor wave associated with compressible response. Comparison of the predictions with those of full numerical simulations and non-linear similarity solutions indicates that this modified incompressible solution predicts reasonably accurate results for the transient decay of the contact pressure from its shocked value to its asymptotic value.
The instability and breakdown of a round variable-density jet

A study has been made of the instability and the subsequent breakdown of axisymmetric jets of helium/air mixtures emerging into ambient air. Although the density of the nozzle gas is less than that of the ambient fluid, the jet is essentially non-buoyant. Two kinds of instability are observed in the near field, depending upon the mean flow parameters. When the ratio of the exiting nozzle fluid density to ambient fluid density is ρe/ρ∞ > 0.6, shear-layer fluctuations evolve in a fashion similar to that observed in constant-density jets: the power spectrum near the nozzle is determined by weak background disturbances whose subsequent spatial amplification agrees closely with the spatial stability theory. When the density ratio is less than 0.6, an intense oscillatory instability may also arise. The overall behaviour of this latter mode (to be called the ‘oscillating’ mode) is shown to depend solely upon the density ratio and upon D/θ, where D is the nozzle diameter and θ is the momentum thickness of the boundary layer at the nozzle exit. The behaviour of this mode is found to be independent of the Reynolds number, within the range covered by the present experiments. This is even true in the immediate vicinity of the nozzle where, unlike in the case of shear-layer modes, the intensity of the oscillating mode is independent of background disturbances. The streamwise growth rate associated with the oscillating mode is not abnormally large, however. The frequency of the oscillating mode compares well with predictions based on a spatio-temporal theory, but not with those of the standard spatial theory. From high-speed films it is found that the overall structure of the oscillating mode repeats itself with extreme regularity. The high degree of repeatability of the oscillating mode, in association with a strong pairing process, leads to abnormally large centreline velocity fluctuation, with its root-mean-square value being about 30 % of the nozzle exit velocity. Energetic and highly regular pairing is found also to lead to the early and abrupt breakdown of the potential core. The regularity often extends even to the finer structure immediately downstream of the breakdown. An attempt is made to explain these special features both in terms of the large-amplitude vorticity field, and in terms of the theoretically predicted space–time evolution of wave packets.
Unsteady RANS simulation of oscillating mould flows

Mould flow oscillations are of major importance for the performance of the continuous casting process. They are suspected to promote entrainment of slag and other unwanted secondary phases into the melt pool. These oscillating turbulent flows are investigated by means of numerical simulations. The numerical model is based on the equation of continuity and the unsteady Reynolds averaged Navier–Stokes equations. The system of flow equations is closed by a Reynolds stress turbulence model in combination with non‐equilibrium wall functions.
Description of Creep in Inherently Anisotropic Frictional Materials

This paper presents a mathematical framework for modeling the creep phenomenon in frictional materials exhibiting a strong inherent anisotropy. The instantaneous time-independent response is described by invoking a plasticity framework which incorporates a scalar anisotropy parameter. The latter is a function of mixed invariants of the stress and microstructure tensors. The creep is assumed to be associated with progressive rearrangement of material structure. The evolution of the elastic compliance is established based on a homogenization procedure for periodic media. In the plastic range, the problem is formulated in terms of evolution of the eigenvalues of the microstructure tensor, while the eigenvectors are preserved. The framework is applied to investigate the creep characteristics of sedimentary rocks, which exhibit a transverse isotropy. In particular, a numerical analysis is carried out to examine the basic trends in the mechanical response of Tournemire shale.
Short-wave and wave group scattering by submerged porous plate

An analytical solution for waves propagating through a horizontal porous plate of finite thickness is obtained. The objective of the plate is to reduce the incident short-wave energy and the long-wave energy as well. Consequently, in this study the plate is analyzed in a global perspective [i.e., considering its response to obliquely incident short waves (both regular and irregular) and wave groups (with the consequent generation of free and locked long waves)]. To solve the propagation of regular and irregular waves, an eigenfunction expansion is used and the results are verified with experimental data showing good agreement. The propagation of a wave group past a horizontal porous plate is studied using a multiple-scale perturbation method, and an analytical solution is presented. The results show that the generated long waves are present on both sides of the plate and that maximum short-wave reflection is associated with maximum long-wave transmission.
Wavenumber-based filtering of marine point-source data

In seismic processing, plane‐wave decomposition has played a fundamental role, serving as a basis for developing sophisticated processing techniques valid for depth‐dependent models. By comparing analytical expressions for the decomposed wavefields, we review several processing algorithms of interest for the geophysicist. The algorithms may be applied to marine point‐source data acquired over a horizontally layered viscoelastic and anisotropic medium. The plane‐wave decomposition is based on the Fourier transform integral for line‐source data and the Hankel transform integral for point‐source data. The involved wavenumber integrals of the cosine or Bessel‐function type are difficult to evaluate accurately and efficiently. However, a number of the processing techniques can easily be run as a filtering operation in the spatial domain without transforming to the wavenumber domain. The mathematical expressions for the spatial filters are derived using plane wave analysis. With numerical examples, we demonstra.
The Large‐Time Solution of Burgers' Equation with Time‐Dependent Coefficients. I. The Coefficients Are Exponential Functions

In this paper, we consider an initial‐value problem for Burgers' equation with variable coefficients ut+Φ(t)uux=Ψ(t)uxx,−∞0,where x and t represent dimensionless distance and time, respectively, and Ψ(t) , Φ(t) are given functions of t. In particular, we consider the case when the initial data have algebraic decay as |x|→∞ , with u(x,t)→u+ as x→∞ and u(x,t)→u− as x→−∞ . The constant states u+ and u−(≠u+) are problem parameters. Two specific initial‐value problems are considered. In initial‐value problem 1 we consider the case when Φ(t)=et and Ψ(t)=1 , while in initial‐value problem 2 we consider the case when Φ(t)=1 and Ψ(t)=et . The method of matched asymptotic coordinate expansions is used to obtain the large‐t asymptotic structure of the solution to both initial‐value problems over all parameter values.
Modeling of photonic crystal fibers from the scalar wave equation with a purely transverse linearly polarized vector potential

In this work, we propose a new technique for modeling light propagation in photonic crystal fibers where the electric field is evaluated from a purely transverse linearly polarized vector potential. The vector potential in a nonuniform dielectric obeys a wave equation coupled to the scalar potential, but it can be reduced to a scalar wave equation when the coupling term is ignored to the lowest order approximation. We show that this method gives reliable results for photonic crystal fibers when the scalar analysis is improved by a perturbational correction.
Spectroscopic Study of Quantized Breakdown Voltage States of the Quantum Hall Effect

Quantized breakdown voltage states are observed in a second, wide, high-quality GaAs/AlGaAs sample made from another wafer, demonstrating that quantization of the longitudinal voltage drop along the sample is a general feature of the quantum Hall effect in the breakdown regime. The voltage states are interpreted in a simple energy conservation model as occurring when electrons are excited to higher Landau levels and then return to the original level. A spectroscopic study of these dissipative voltage states reveals how well they are quantized. The statistical variations of the quantized voltages increase linearly with quantum number.