Miracle-dz/UniFAR-FTUs huggingface dataset:
Missing mass or missing light

Disney et al. (1989) have argued that the observational data are consistent with disk galaxies being optically thick, particularly in their inner regions. Here, these results are used to reinterpret the radial surface-brightness distributions of spiral galaxies. It is found that the fitting of a profile with an absorbed disk plus bulge leads to both disk and bulge masses (mass in luminous material) that are larger than previously assumed. In addition, it is shown how the rotation velocity, as determined from optical data in the central regions, may systematically underestimate the true rotational velocity in an optically thick disk. If the bulges of late-type galaxies are as large as is hypothesized, then this has important implications in models of galaxy evolution and galaxy dynamics. The model greatly reduces or even eliminates the need for dark matter within the optical radius; it removes a major argument against S0 evolution from later-type galaxies; it accounts for the similarity of rotation curve forms among galaxies of different morphological types; and it leads to a further reappraisal of the observed constancy of the extrapolated central surface brightness of galactic disks.
A scaling equation with only non-measurable orthogonal solutions

In this paper we construct a non-measurable scaling function for the scaling equation φ(x) = φ(3x) + φ(3x− 2) + φ(3x− 4), using the Axiom of Choice. We prove that –apart from being non-measurable– it satisfies the classical conditions for a scaling function to lead to orthonormal wavelets. While non-measurable functions are not directly useful for numerical calculations, the example given here explains the possible anomalous behaviour of numerical methods. Indeed the origin of this paper lies in the solution of the scaling equation above, calculated on a finite grid consisting of the points i/3k , 0 ≤ i < 2.3k. The result is φ ( i 3k ) = { 0 i odd, 1 i even. This finite approximation seemingly satisfies the conditions for a scaling equation but, as we show here, any extension is either non-measurable or not orthogonal. While in this case, and for the chosen grid, the strange behaviour is apparent from the graph of the approximating function which looks like a comb, there is of course no guarantee that this will be clear in different situations. Introduction In the sequel, any finite sequence of scalars is supposed to be padded at left and at right with zeros. If e.g. the sequence (a0, . . . , ak) is given, this implies that ai = 0 for i < 0, as well as for i > k. If no boundaries for a summation are, implicitly or explicitly, given the index range is Z. Let m, an integer greater than 1, be the so-called scaling factor . A sequence (a0, . . . , an) of complex numbers is called a set of scaling coefficients iff it satisfies ∑
Linear theory of momentum fluxes in 3-D flows with turning of the mean wind with height

Current orographically forced gravity-wave-drag parametrization schemes in numerical weather-prediction models are based on two-dimensional linear momentum-flux theory. the vertical flux of horizontal-momentum vector is considered parallel to the surface-stress vector and independent of height unless the Richardson number falls below a quarter, or a critical level exists where the mean wind becomes zero in the direction of the flux vector. Non-zero gravity-wave drag is then taken to be parallel and opposite to the flux vector. Consideration of the full three-dimensional linear problem reveals a number of fundamental differences: (i) the drag force is perpendicular to the mean wind where there is no wavebreaking, and (ii) the variation of the stress vector with height is dependent on the wave-number decomposition of the underlying orography. For a general orographic profile having a continuous Fourier spectrum spanning an azimuthal angle of 180°: (a) critical levels exist at every height in the atmosphere for any wind profile, and (b) the momentum-flux vector decreases in magnitude and turns with height.
Electrical conductivity and equation-of-state study of warm dense copper: Measurements and quantum molecular dynamics calculations

Absolute measurements of the pressure and the electrical conductivity of expanded copper in the warm dense matter regime ({rho}=0.5-0.3 g/cm{sup 3} and 6000 K<T<30 000 K) are obtained in an isochoric plasma closed-vessel (EPI). Quantum molecular dynamics simulations are found to be in excellent agreement with the experimental results, allowing for a detailed interpretation of the optical conductivities. A shift in energy of the 4s{yields}4p atomic line is explained by the rise of ionization with temperature.
Computed tomography of refractive index by low-coherence interferometry

We present a 3D imaging system for simultaneously imaging the distributions of refractive index and optical absorption using a transmission Fourier-domain low-coherence interferometer. The forward-scattering light travelling through a sample interferes with a reference light beam. The projections of refractive index and optical absorption within the sample are calculated from measured interference fringes. We acquire the projections at sufficient angular views and reconstruct the distributions of refractive index and optical absorption using the filter back-projection algorithm. The proposed method is experimentally verified by using a plastic tube phantom.
Spectral hole burnings at high energy tails in spontaneous emission and hot carrier relaxation in InGaAsP lasers

Spectral hole burnings in spontaneous emission spectra from 1.3 μm InGaAsP lasers were found. The results are understood on the basis of population burnings of holes associated with the saturation of intervalence-band absorption. Theoretical results on hot carrier relaxation are shown to explain the population burnings, pointing out an importance of nonequilibrium optical phonon populations in the active layers of long wavelength InGaAsP lasers and light emitting diodes (LED's).
Superfluid Hydrodynamics in Rotating Neutron Stars. II. Dissipative Effects

The Newtonian superfluid hydrodynamic equations describing the outer-core regions of neutron stars are generalized to include dissipation. The effects of viscosity, thermal conductivity, and mutual friction (due to the scattering of electrons off the neutron and proton vortices) are included. The low-frequency-long-wavelength limit is taken to obtain a set of equations suitable for studies of p-modes in rapidly rotating neutron stars. An energy functional is constructed which determines the damping times due to the various forms of dissipation.
On the anelastic approximation for a compressible atmosphere

Abstract The equations of motion for a compressible atmosphere under the influence of gravity are reexamined to determine the necessary conditions for which the anelastic approximation holds. These conditions are that (i) the buoyancy force has an O (1) effect in the vertical momentum equation, (ii) the characteristic Vertical displacement of an air parcel is comparable to the density scale height, and (iii) the horizontal variations of the thermodynamic state variables at any height are small compared to the static reference value at that height. It is shown that, as a consequence of these assumptions, two additional conditions hold for adiabatic flow. These ancillary conditions are that (iv) the spatial variation of the base-state entropy is small, and (v) the Lagrangian time scale of the motions must be lager than the inverse of the buoyancy frequency of the base state. It is argued that condition (iii) is more fundamental than (iv) and that a flow can be anelastic even if condition (iv) is violated pr.
A detailed view of a molecular cloud in the far outer disk of M 33. Molecular cloud formation in M 33

The amount of H2 present in spiral galaxies remains uncertain, particularly in the dim outer regions and in low-metallicity environments. We present high-resolution CO(1-0) observations with the Plateau de Bure interferometer of the most distant molecular cloud in the local group galaxy M 33. The cloud is a single entity rather than a set of smaller clouds within the broad beam of the original single-dish observations. The interferometer and single-dish fluxes are very similar and the line widths are indistinguishable, despite the difference in beamsize. At a spatial resolution of 10 pc, beyond the optical radius of the M 33, the CO brightness temperature reaches 2.4 Kelvins. A virial mass estimate for the cloud yields a mass of 4.3 × 104 Ms and a ratio N(H2)/ICO(1-0) ≃ 3.5 × 1020 cm-2/(K km s-1). While no velocity gradient is seen where the emission is strong, the velocity is redshifted to the extreme SW and blue-shifted to the far NE. If the orientation of the cloud is along the plane of the disk (i.e. not perpendicular), then these velocities correspond to slow infall or accretion. The rather modest infall rate would be about 2 × 10-4 Ms yr-1. Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). Data cube in FITS files is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat? J/A+A/548/A52
Atomic and ionized hydrogen near IC 5146 (S125)

We report synthesis observations in continuum and H I line emission at 21 cm of a 2/sup 0/ field containing the emission nebula IC 5146. The resolution is 2'. 0 x 2'. 7 by 0.66 km s/sup -1/ in radial velocity. Low-order spatial components from a single telescope have been added to the line maps.
Observational signatures of rapidly rotating, pulsating B stars

The effects of the geometric distortion of a rapidly rotating star on the relative amplitudes of radial velocity and luminosity variations are modelled. The possibility of determining the inclination angle of the rotation axis of a rapidly rotating star, from observations of its radial velocity and luminosity variations, is then explored and the nature of these effects for a model of an early B main-sequence star are presented. It is found that this approach holds sufficient promise that more detailed calculations should be embarked upon.
Order Reduction of Discrete-Time System Via Bilinear Routh Approximation

On presente une methode melant la methode d'approximation de Routh avec la transformation bilineaire et permettant de reduire les systemes discrets. Cette methode d'approximation bilineaire de Routh a tous les avantages de la methode d'approximation de Routh, sans le probleme de valeur initiale cause par la transformation bilineaire. Un exemple numerique est propose pour illustrer la procedure
Hypothetical hard structures of carbon with cubic symmetry

In this work we performed ab initio pseudopotential, density functional calculations of the structure and electronic properties of two hypothetical carbon structures with cubic symmetry: C6 bcc, body centered with 12 atoms per cubic unit cell, and C20 sc, simple cubic with 20 atoms per unit cell. The former is semiconducting with an indirect gap of 2.5 eV—within the local density approximation to the exchange and correlation energy functional—while the latter is metallic. Both have similar zero-pressure densities of about one atom per 6.9 A 3 , which is intermediate between graphite and diamond, and similar bulk moduli of about 350 GPa at ambient conditions. Both are metastable with respect to graphite and diamond, and no phase transition is expected in the range of pressures studied.
Gaussian beams in elastic 2-D laterally varying layered structures

Summary. In a paper by Cervený & Psencik, high-frequency Gaussian beams in elastic 2-D, laterally inhomogeneous, smooth media were investigated as asymptotic high-frequency solutions of elastodynamic equations, concentrated close to rays of P- and S-waves. This paper generalizes the above results for 2-D, laterally inhomogeneous, layered structures. Gaussian beams concentrated close to any multiply-reflected, possibly converted, ray are investigated. Gaussian beams are regular everywhere, including caustic regions. The paraxial ray approximation, which allows the wavefield in the zero-order ray approximation to be evaluated not only directly on the ray, but also in its vicinity, is derived as a limiting case of the Gaussian beams.
Vortex Pattern Comparison for Periodic and Harmonic Combined Cross-Flow and In-Line Forced Oscillations

For prediction of vortex-induced vibrations (VIV) the empirical models apply hydrodynamic coefficients to represent the fluid forces on the slender structures. The coefficients are in most cases found by measuring forces on a rigid cylinder under harmonic pure in-line (IL) or pure cross-flow (CF) forced motions, and are generally presented as functions of non-dimensional motion amplitude and frequency. The objective of the present work has been to find hydrodynamic coefficients for realistic combinations of CF and IL motions. Such trajectories were found from measured VIV of a flexible beam, and then used as forced motions of a rigid cylinder in uniform flow. Hydrodynamic forces were measured and used for calculation of hydrodynamic coefficients. The diameter of the rigid cylinder was larger than for the flexible beam in order to obtain optimum conditions for both experiments. However, both Reynolds number and non-dimensional frequency were identical for the two test types. The flexible beam oscillations were not perfectly periodic, but close to. More than one periodic trajectory could hence be identified as representative for the observed response, and these were used as forced motions in order to study the variability of the hydrodynamic coefficients. Alternative harmonic loops were also constructed in order to investigate the potential for using coefficients from harmonic tests as basis for empirical models. The vortex shedding process behind the cylinder has been mapped using Particle Image Velocimetry (PIV). PIV planes can picture the difference in cylinder wake for these trajectories and thus help to understand the process. The vorticity patterns at instantaneous positions for both periodic and harmonic trajectories are obtained. The vortices were mapped and the forces were measured simultaneously. Higher order harmonic components of the force are seen for all types of trajectories, and a correlation between these components and the vortex shedding pattern is observed.Copyright © 2009 by ASME
Radiation Pattern Synthesis for Conformal Antenna Arrays

The synthesis of conformal antenna arrays is complicated by the impossibility factorizing the analytical expression for the power pattern into an element factor and an array factor. This article describes a general method of pattern synthesis that, given a well-defined single-element power pattern, is applicable to arrays of arbitrary geometry. Essentially, the method uses simulated annealing to optimize the excitation distribution so as to minimize the difference between the power pattern it generates and the desired power pattern.
CSVD: approximate similarity searches in high-dimensional spaces using clustering and singular value decomposition

Many data-intensive applications, such as content-based retrieval of images or video from multimedia databases and similarity retrieval of patterns in data mining, require the ability of efficiently performing similarity queries. Unfortunately, the performance of nearest neighbor (NN) algorithms, the basis for similarity search, quickly deteriorates with the number of dimensions. In this paper we propose a method called Clustering with Singular Value Decomposition (CSVD), combining clustering and singular value decomposition (SVD) to reduce the number of index dimensions. With CSVD, points are grouped into clusters that are more amenable to dimensionally reduction than the original dataset. Experiments with texture vectors extracted from satellite images show that CSVD achieves significantly higher dimensionality reduction than SVD along for the same fraction of total variance preserved. Conversely, for the same compression ratio CSVD results in an increase in preserved total variance with respect to SVD (e.g., at 70% increase for a 20:1 compression ratio). Then, approximate NN queries are more efficiently processed, as quantified through experimental results.
A Fractal Approach to Identifying Urban Boundaries. 城市边界识别的分形方法

Fractal geometry can be used for determining the morphological boundaries of metropolitan areas. A two-step method is proposed here: (1) Minkowski's dilation is applied to detect any multiscale spatial discontinuity and (2) a distance threshold is located on the dilation curve corresponding to a major change in its behavior. We therefore measure the maximum curvature of the dilation curve. The method is tested on theoretical urban patterns and on several European cities to identify their morphological boundaries and to track boundary changes over space and time. Results obtained show that cities characterized by comparable global densities may exhibit different distance thresholds. The less the distances separating buildings differ between an urban agglomeration and its surrounding built landscape, the greater the distance threshold. The fewer the buildings that are connected across scales, the greater the distance threshold.
Transport in superconductor/ferromagnet/superconductor junctions dominated by interface resistance

We report on high-sensitivity measurements performed on weakly resistive Nb/Al/Gd/Al/Nb ferromagnetic rare-earth-based junctions. High interface barriers in such junctions can strongly modify interplay between ferromagnetism and superconductivity. We show in the present paper that for such ferromagnetic/superconductor junctions that the main contribution to the resistance comes from interface scattering. On the other hand, measurements on identical nonmagnetic rare-earth-based junctions such as Nb/Al/Y/Al/Nb exhibit opposite behavior; hence most resistance comes from the bulk. A theoretical description of the temperature dependence of the superconductor/ferromagnet/superconductor $(S/F/S)$ junction resistance is given through a temperature dependent Blonder-Tinkham-Klapwick theory for an energy range well below the superconducting gap scale of the Al/Nb bilayer. Such a theoretical description proves that interfacial scattering is of crucial importance when experimenting in $S/F$ systems using gadolinium.
Radio imaging of head-tailed galaxies from an in-falling filament of the Horologium-Reticulum supercluster

We present a multi-wavelength study of a pair of head-tailed radio galaxies in an in-falling filament of the A3125/A3128 cluster complex which is located at the centre of the massive Horologium Reticulum Supercluster (HRS). We compare the large-scale structure evident from extensive optical observations of the region with the dynamical information gleaned from the morphology of the radio jets. We argue that in addition to the acceleration produced by in-fall toward the centre of A3125, the closest galaxy cluster, the radio jets show some evidence of bulk motion along the major filament of the HRS.To search for other articles by the author(s) go to: http://adsabs.harvard. edu/abstract_service. html
ADI FD schemes for the numerical solution of the three-dimensional Heston–Cox–Ingersoll–Ross PDE

This paper deals with the numerical solution of the time-dependent, three-dimensional Heston–Cox–Ingersoll– Ross PDE, with all correlations nonzero, for the fair pricing of European call options. We apply a finite difference dis-cretization on non-uniform spatial grids and then numerically solve the semi-discrete system in time by using an Alternating Direction Implicit scheme. We show that this leads to a highly efficient and stable numerical solution method.
SHORT-TIME EXPANSION OF CHARACTERISTIC FUNCTIONS IN A ROUGH VOLATILITY SETTING WITH APPLICATIONS

We derive a higher-order asymptotic expansion of the conditional characteristic function of the increment of an Itô semimartingale over a shrinking time interval. The spot characteristics of the Itô semimartingale are allowed to have dynamics of general form. In particular, their paths can be rough, that is, exhibit local behavior like that of a fractional Brownian motion, while at the same time have jumps with arbitrary degree of activity. The expansion result shows the distinct roles played by the different features of the spot characteristics dynamics. As an application of our result, we construct a nonparametric estimator of the Hurst parameter of the diffusive volatility process from portfolios of short-dated options written on an underlying asset.
Tax Incentives, Digital Transformation and Enterprise Innovation

Taking China's A-share manufacturing listed companies from 2013 to 2020 as samples, this paper discusses and tests the impact of tax incentives and digital transformation on enterprise innovation, and further explores the moderating effect of digital transformation on the relationship between tax incentives and enterprise innovation. The research results show that tax incentives play a significant positive role in promoting enterprise innovation, and digital transformation can effectively promote enterprise innovation and positively regulate the innovation incentive effect of tax incentive policies, indicating that enterprise digital transformation is conducive to the play of tax incentive policies, so that enterprise innovation can be better promoted and promoted. The results of heterogeneity test show that the promoting effect of tax incentives and digital transformation on enterprise innovation is more obvious in state-owned enterprises and non-high-tech enterprises, while the moderating effect of digital transformation on the incentive effect of tax incentives is more prominent in high-tech enterprises.
On the prediction of ENSO: a study with a low-order Markov model

A linear model best fit to the Zebiak and Cane (1987) ENSO forecast model (ZC) is used to study the model's prediction skill. Multivariate empirical orthogonal functions (MEOFs) obtained from the sea surface temperature anomaly, sea level and wind stress anomaly fields in a suite of 3-year forecast runs of ZC starting from the monthly initial conditions in the period January 1970 to December 1991, are used to construct a series of seasonally varying linear Markov models. It is found that the model with 18 MEOFs fits the original nonlinear model reasonably well and has comparable or better forecast skill. Assimilating the observed SST into the initial conditions further improves forecast skill at short lead times (< 9 months). The transient initial error growth in the model's prediction is attributed to the non-self-adjoint property as in Farrell and Blumenthal. Initial error grows fastest starting from spring and slowest starting from late summer and is sensitive to the initial error structures. Two singular vectors (SVs) of the linear evolution operator have significant transient growth dominating the total error growth. Since the optimal perturbation (fastest SV) has mostly high MEOF components, the error growth tends to be larger when there are more high mode components in the initial error fields. This result suggests a way to filter the initial condition fields: the MEOFs higher than the 18th in the initial fields are mostly noise and removing them improves prediction skill. The forecasts starting from late summer have the best predictability because the fastest growth season (summer) is just avoided. The well known, very rapid decline in forecast skill in the boreal spring (the “spring barrier”) is here attributed to the smallness of the signal to be forecast: the standard deviation of the NIN03 SST anomaly is smallest in spring. DOI: 10.1034/j.1600-0870.1994. 00013.x