Miracle-dz/UniFAR-FTUs huggingface dataset:
High filling fraction gallium phosphide inverse opals by atomic layer deposition

High filling fraction gallium phosphide (GaP) inverse opals were fabricated by atomic layer deposition within the void spaces of silica colloidal crystal templates. Depositions were performed from 400to500°C using trimethylgallium and tris(dimethylamino)phosphine precursors. The resulting films were characterized by optical reflectance, which indicated infiltration as high as 100% of the conformal film growth maximum, corresponding to a volume filling fraction of 0.224. X-ray diffraction measurements confirmed the crystallinity of the film. These results indicate the fabrication of three-dimensional photonic crystals using a III-V optoelectronic material with sufficient dielectric contrast to form a full photonic band gap in the visible.
B/T-ratios in the Hubble sequence

Abstract We discuss bulges in the Hubble sequence, based on the analysis of deep near-IR images for a sample of 216 nearby galaxies. Using a 2D multicomponent decomposition code, we find that the average bulge-to-total (B/T) flux ratio is less than 0.25 across all morphological types. Even 50% of the early-type galaxies (S0-S0/a) are found to have nuclear bars, inner disks or nuclear rings inside the bulge. Also, the shape parameter of the bulge is on average ≤2 for all Hubble types. Our results are consistent with the picture in which bulges even in many early-type galaxies were formed by secular evolutionary processes. We find two galaxies that might be stripped spirals, belonging to the so far empty S0c morphological class introduced by van den Bergh (1979).
On Gelfand pairs associated to transitive groupoids

Let \(G\) be a topological locally compact, Hausdorff and second countable groupoid with a Haar system and \(K\) a compact subgroupoid of \(G\) with a Haar system too. \((G,K)\) is a Gelfand pair if the algebra of bi-\(K\)-invariant functions is commutative under convolution. In this paper, we give a characterization of Gelfand pairs associated to transitive groupoids which generalize a well-known result in the groups case. Using this result, we prove that the study of Gelfand pairs associated to transitive groupoids is equivalent to that of Gelfand pairs associated to its isotropy groups.
Modelling long-term investment returns via Bayesian infinite mixture time series models

This paper introduces the class of Bayesian infinite mixture time series models first proposed in Lau & So (2004) for modelling long-term investment returns. It is a flexible class of time series models and provides a flexible way to incorporate full information contained in all autoregressive components with various orders by utilizing the idea of Bayesian averaging or mixing. We adopt a Bayesian sampling scheme based on a weighted Chinese restaurant process for generating partitions of investment returns to estimate the Bayesian infinite mixture time series models. Instead of using the point estimates, as in the classical or non-Bayesian approach, the estimation in this paper is performed by the full Bayesian approach, utilizing the idea of Bayesian averaging to incorporate all information contained in the posterior distributions of the random parameters. This provides a natural way to incorporate model risk or uncertainty. The proposed models can also be used to perform clustering of investment returns and detect outliers of returns. We employ the monthly data from the Toronto Stock Exchange 300 (TSE 300) indices to illustrate the implementation of our models and compare the simulated results from the estimated models with the empirical characteristics of the TSE 300 data. We apply the Bayesian predictive distribution of the logarithmic returns obtained by the Bayesian averaging or mixing to evaluate the quantile-based and conditional tail expectation risk measures for segregated fund contracts via stochastic simulation. We compare the risk measures evaluated from our models with those from some well-known and important models in the literature, and highlight some features that can be obtained from our models.
EFFECT OF MUSCLE TENSION ON NON-LINEARITIES IN THE APPARENT MASSES OF SEATED SUBJECTS EXPOSED TO VERTICAL WHOLE-BODY VIBRATION

In subjects exposed to whole-body vibration, the cause of non-linear dynamic characteristics with changes in vibration magnitude is not understood. The effect of muscle tension on the non-linearity in apparent mass has been investigated in this study. Eight seated male subjects were exposed to random and sinusoidal vertical vibration at five magnitudes (0·35–1·4 m/s2 r.m.s.). The random vibration was presented for 60 s over the frequency range 2·0–20 Hz; the sinusoidal vibration was presented for 10 s at five frequencies (3·15, 4·0, 5·0, 6·3 and 8·0 Hz). Three sitting conditions were adopted such that, in two conditions, muscle tension in the buttocks and the abdomen was controlled. It was assumed that, in these two conditions, involuntary changes in muscle tension would be minimized. The force and acceleration at the seat surface were used to obtain apparent masses of subjects. With both sinusoidal and random vibration, there was statistical support for the hypothesis that non-linear characteristics were less clear when muscle tension in the buttocks and the abdomen was controlled. With increases in the magnitude of random vibration from 0·35 to 1·4 m/s2 r.m.s., the apparent mass resonance frequency decreased from 5·25 to 4·25 Hz with normal muscle tension, from 5·0 to 4·38 Hz with the buttocks muscles tensed, and from 5·13 to 4·5 Hz with the abdominal muscles tensed. Involuntary changes in muscle tension during whole-body vibration may be partly responsible for non-linear biodynamic responses.
Fusion of intensity and inter-component chromatic difference for effective and robust colour edge detection

Edge detection, especially from colour images, plays very important roles in many applications for image analysis, segmentation and recognition. Most existing methods extract colour edges via fusing edges detected from each colour components or detecting from the intensity image where inter-component information is ignored. In this study, an improved method on colour edge detection is proposed in which the significant advantage is the use of inter-component difference information for effective colour edge detection. For any given colour image C, a grey D-image is defined as the accumulative differences between each of its two colour components, and another grey R-image is then obtained by weighting of D-image and the grey intensity image G. The final edges are determined through fusion of edges extracted from R-image and G-image. Quantitative evaluations under various levels of Gaussian noise are achieved for further comparisons. Comprehensive results from different test images have proved that this approach outperforms edges detected from traditional colour spaces like RGB, YCbCr and HSV in terms of effectiveness and robustness.
Mixotrophic trade‐off under warming and UVR in a marine and a freshwater alga

Mixotrophic protists combine phagotrophy and phototrophy within a single cell. Greater phagotrophic activity could reinforce the bypass of carbon (C) flux through the bacteria‐mixotroph link and thus lead to a more efficient transfer of C and other nutrients to the top of the trophic web. Determining how foreseeable changes in temperature and UVR affect mixotrophic trade‐offs in favor of one or the other nutritional strategy, along the mixotrophic gradient, is key to understanding the fate of carbon and mineral nutrients in the aquatic ecosystem. Our two main hypotheses were: (i) that increased warming and UVR will divert metabolism toward phagotrophy, and (ii) that the magnitude of this shift will vary according to the organism's position along the mixotrophic gradient. To test these hypotheses, we used two protists (Isochrysis galbana and Chromulina sp.) located in different positions on the mixotrophic gradient, subjecting them to the action of temperature and of UVR and their interaction. Our results showed that the joint action of these two factors increased the primary production:bacterivory ratio and stoichiometric values (N:P ratio) close to Redfield's ratio. Therefore, temperature and UVR shifted the metabolism of both organisms toward greater phototrophy regardless of the original position of the organism on the mixotrophic gradient. Weaker phagotrophic activity could cause a less efficient transfer of C to the top of trophic webs.
The effect of the GARCH(1, 1) on autocorrelation tests in dynamic systems of equations

Using Monte Carlo methods, the properties of systemwise generalizations of the Breusch–Godfrey test for autocorrelated errors are studied when there are some kinds of GARCH effects among the errors. The analysis, regarding the size of the test, reveals that the GARCH have considerable effects of the properties of the test regarding the size, especially in large systems of equations. The corrected LR tests, however, have been shown to perform satisfactorily in small systems when the errors are white noise or they have low GARCH effects, whilst the commonly used TR2 test behaves badly even in single equations. All tests perform badly, however, when the number of equations increases and the GARCH effect is strong. As regards the power of the test, the GARCH was not found to have any significant effects on the power properties of the test.
Wave propagation in pulsar magnetospheres - Refraction of rays in the open flux zone

The propagation of waves through a relativistically outflowing electron-positron plasma in a very strong dipolar magnetic field, conditions expected in pulsar magnetospheres, is investigated. Halmilton's equations is derived for the propagation of rays through a plasma which is inhomogeneous in density, magnetic field directions, and Lorentz factor. These equations are solved for rays propagating through the plasmas outflowing along the 'open' dipolar field lines in which the density decreases inversely as the radius cubed and in the case where gradients transverse to the radial direction exist. In the radial case, the effects of refraction on pulse profiles, spectrum, and polarization are examined, and the effects of a transverse gradient are indicated. Attention is given to models in which the observed broad bandwidth in the radio emission has its origin in a radius to frequency map. Models with broad-band emission at a single radius are also studied. These are compared to observations of pulse width and pulse component separation as a function of frequency. The origin of 'orthogonal modes' is discussed.
Early type galaxies, dark halos, and gravitational lensing statistics

We present calculations of the expected statistics of gravitational lensing of quasars in the Hubble Space Telescope snapshot survey. We first model early-type (elliptical and S0) galaxies using their observed surface brightness profiles and dynamically inferred mass-to-light ratios. Our work improves upon previous calculations, which have generally approximated the galaxy potentials by isothermal spheres. For standard cosmologies, the predicted number of lensed quasars in the survey is 1.1-2.8, 98% of which have image separations less than 2″, compared to the four lenses observed, two of which have separations greater than 2″. These constant mass-to-light ratio models are rejected
Improving signal capture of CMA adaptive array using weight norm control

The CMA (constant modulus algorithm) adaptive array was developed to capture the desired signal possessing constant envelope properties. The CMA is an algorithm that is suitable for mobile communications because it has the great advantage of requiring no prior knowledge about the transmitted signal. We propose an alternative norm-constrained CMA. It features putting a hard or rigid constraint on the weight norm. We examine, via computer simulation, the directional patterns after convergence and the output power characteristics versus the iteration number of weight update. In addition, we analyse the capture performance of the proposed system using a 2-wave radio model. The results show that the proposed norm-constrained CMA yields lower sidelobes, resulting in higher SINR, and better signal capture performance than the original CMA and conventional norm-constrained CMA.
Diffeomorphism groups and nonlinear quantum mechanics

This talk is dedicated to my friend and collaborator, Prof. Dr. Heinz-Dietrich Doebner, on the occasion of his 80th birthday. I shall review some highlights of the approach we have taken in deriving and interpreting an interesting class of nonlinear time-evolution equations for quantum-mechanical wave functions, with few equations; more detail may be found in the references. Then I shall comment on the corresponding hydrodynamical description.
Local Sensitivity Analysis in Estimation Problems

This article deals with the problem of local sensitivity analysis, that is, how sensitive are the results of a statistical analysis to changes in the data? A general methodology of sensitivity analysis is applied to some statistical problems. The proposed methods are applicable to any statistical problem that can be expressed as an optimization problem or that involves solving a system of equations. As some particular examples, the methodology is applied to the maximum likelihood method, the standard and constrained methods of moments and the standard and constrained probability weighted moments methods. Unlike the standard method of moments, the constrained method of moments ensures that the obtained estimates are always consistent with the data. Closed analytical formulas for the calculation of these local sensitivities are derived. The obtained sensitivities include: (a) the objective function sensitivities to data points and (b) the sensitivities of the estimated parameters to data points. The derived formulas for the sensitivities are based on recent results in the area of mathematical programming. Several examples of parameter estimation problems are used to illustrate the methodology.
Vibrational imaging and microspectroscopies based on coherent anti-Stokes Raman scattering microscopy

For noninvasive characterization of chemical species or biological components within a complex heterogeneous system, their intrinsic molecular vibrational properties can be used in contrast mechanisms in optical microscopy. A series of recent advances have made coherent anti-Stokes Raman scattering (CARS) microscopy a powerful technique that allows vibrational imaging with high sensitivity, high spectral resolution and three-dimensional sectioning capability. In this review, we discuss theoretical and experimental aspects of CARS microscopy in a collinear excitation beam geometry. Particular attention is given to the underlying physical principles behind the new features of CARS signal generation under tight focusing conditions. We provide a brief overview of the instrumentation of CARS microscopy and its experimental characterization by means of imaging of model systems and live unstained cells. CARS microscopy offers the possibility of spatially resolved vibrational spectroscopy, providing chemical and physical structure information of molecular specimens on the sub-micrometre length scale. We review multiplex CARS microspectroscopy allowing fast acquisition of frequency-resolved CARS spectra, time-resolved CARS microspectroscopy recording ultrafast Raman free induction decays and CARS correlation spectroscopy probing dynamical processes with chemical selectivity.
Stochastic modelling and estimation for cyclic pressure variations in spark ignition engines

A new method of fitting linearised, parametric stochastic models of cycle-by-cycle variations of pressure, during the combustion region of a spark ignition petrol engine, is described. The technique is based on stochastically fitting the combustion models to the covariance function of the measured pressure fluctuations, obtained by averaging over the entire ensemble of measured cycles. Comparisons, for two specific combustion models, with corresponding results obtained by deterministic fitting on a cycle-by-cycle basis, show that the new method gives a similar degree of fit, but with much improved computational efficiency. It is also demonstrated that the degree of fit to the data can be further improved by modelling the residual error between the data and the combustion models in terms of Chebyshev polynomials: the parameters in these polynomials may be determined by stochastic fitting. The technique has wider applications in the condition monitoring of rotating machinery.
The large-scale structure of the Universe in the frame of the model equation of non-linear diffusion

L'evolution des heterogeneites de densite et du champ de vitesse est etudiee dans un milieu continu en expansion sur la base de l'equation de Burgers (equation de diffusion non lineaire) qui, avec l'equation de continuite incorporant la densite de masse, donne une description approchee de la croissance des heterogeneites de densite a l'etape avancee non lineaire de l'instabilite gravitationnelle
Near-wake structure of an oscillating cylinder: effect of controlled shear-layer vortices

The instantaneous structure of the near wake of a cylinder subjected to small-amplitude perturbations is characterized using high-image-density particle image velocimetry. Emphasis is on control of the small-scale shear-layer vortices, which feed into the Kármán vortices. Modifications of the Kármán vortex formation are classified according to patterns of modulated and locked-on shear-layer vortices. The formation length of the Kármán vortices can be dramatically shortened and, in the limiting case, occur adjacent to the base of the cylinder when it is perturbed at the inherent instability frequency of the shear layer and its subharmonics. Moreover, the induced shear-layer vortices can lead to large-amplitude transverse undulations of the entire near-wake region during formation of the Kármán vortices. These variations of the near-wake structure are further elucidated by considering the transient response of the wake, induced by abrupt cessation and onset of periodic motion of the cylinder. Distinctive intermediate states of the wake arise during relaxation to its asymptotic state; such relaxation requires a very large number of periods of the inherent instability of the shear layer.
A novel FBG en-/decoding scheme for wavelength-time optical CDMA

Two schemes of linear combinatorial code (LCC) coding scheme with different and multiple wavelength bandwidth were proposed using fiber grating cascades in series and parallel, respectively. The system model and probability density function are investigated. Numerical simulation confirmed that bit error ratio (BER) performance largely improved due to that of sub-codeword system. Moreover, the preference of LCC with different wavelength bandwidth is better than that of multiple wavelength bandwidth.
The determination of convex bodies from the mean of random sections

Random sectioning of particles (compact sets in ℝ3 with interior points) is a familiar procedure in stereology where it is used to estimate particle quantities like volume or surface area from planar or linear sections (see, for example, the survey [23] or the book [20]). In the following, we study the problem whether the whole shape of a convex particle K can be estimated from random sections. If E is an IUR (isotropic, uniform, random) line or plane intersecting K then the intersection Xk = K ∩ E is a (k-dimensional, k = 1 or 2) random set. It is clear that the distribution of Xk determines K uniquely and that if E1,…, En are such flats, the most natural estimator for K would be the convex hull
On the sensitivity of solutions of parameterized equations

The sensitivity of a solution of a parameterized equation $F(z,\lambda ) = 0$ with respect to the parameter vector $\lambda $ is usually defined as the change of the state z in dependence of $\lambda $. In other words, for any solution expressible in the form $(z(\lambda ),\lambda )$ with some smooth function $z = z(\lambda )$, the sensitivity is the derivative $Dz(\lambda )$. Typically the solutions form a manifold M in the product of 1the state space and the parameter space and this sensitivity is available only at those points of M where the parameters can be used to define a local coordinate system. This paper introduces a general sensitivity concept which applies at all solutions on M and which includes the earlier definition. Some general geometric interpretations of the new measure are presented and it is shown that the sensitivity analysis can be easily integrated into the solution process. The theory also suggests the introduction of a readily computable second-order sensitivity measure reflectin.
Investigation of flame structures in turbulent partially premixed counter-flow flames using planar laser-induced fluorescence

This paper reports on investigations of structural turbulent flame characteristics using planar laser-induced fluorescence (PLIF) of hydroxyl (OH) radicals. Turbulent, counter-flowing methane/air flames with different equivalence ratios spanning from premixed to partially premixed are investigated. Additionally, Reynolds numbers of these configurations are varied and reach from stable to extinguishing flames. The main objective of this study is to extract topological quantities from spatial OH distributions such as area and local thickness of the OH layer, flame brush, or contours approximating the profile of the stoichiometric mixture fraction. The post-processing procedure applied to extract these quantities from single-shot OH PLIF images is described. It is shown that OH areas shrink with increasing Reynolds number whereas lengths of stoichiometric contour lines are nearly unaffected. This indicates that flame extinction is driven by large scale eddies rather than small scale wrinkling. In addition to also performed quantitative laser Doppler anemometry and Raman/Rayleigh measurements of the same flames, topological studies are helpful in viewing complex turbulent-chemistry interaction. Latter data are essential for validation purposes of large eddy simulations (LES) that predict transient flame movement and thereby spatial OH distributions.
Generation and control of field-aligned flow velocity shear in a fully ionized collisionless plasma

A modified plasma-synthesis method is developed in order to actively control an ion flow energy along magnetic-field lines, where ion and electron emitters of the same diameter are oppositely set at cylindrical machine ends and the ion emitter is concentrically segmented into three sections. The field-aligned ion flows with radially different energies, or ion flow velocity shears, are generated in a radially uniform plasma potential when each section of the segmented ion emitter is individually biased at a positive value above the plasma potential.
Narrow-line Seyfert galaxies with permitted Fe II emission Markarian 507, 5C 3.100, and I Zw 1

Optical, X-ray and and/or IR spectra of Mrk 507, 5C 3.100 and I Zw 1 are compared in a discussion of the bases for classifications of Seyfert 1 and 2 galaxies. Einstein Observatory X ray data indicate that the Seyfert designation requires a continuum extending to X-rays in order to account for permitted Fe II lines observed in Seyfert galaxies. It is suggested that the IR luminosity of I Zw 1, which exceeds the X-ray luminosity by two orders of magnitude, may be accounted for by interaction between companion galaxies. The presence or absence of dense clouds such as those in I Zw 1 is identified as the factor which separates Seyfert galaxies into two mutually exclusive ranges in X-ray luminosity.