Miracle-dz/UniFAR-FTUs huggingface dataset:
Asymptotic skewness and the distribution of maximum likelihood esimators

The maximum likelihood procedure to estimate paraneters of a model has scveral attractive properties including the existence of the covariance matrix which yield asymptotic covariances: for a sample size N the asymptotics are in general of order 1/N. Here we give an asymptotic for the skewness of the distribution of the maximum likelihood estimator of a parameter; this is of order 1/ n2 and this expression is new. Applications relate to the parameters of (i) the Poisson, binomial, and normal density. (ii) the gamna density and (iii) the Beta debsity. Other application are being considered. The expression for the asymptotic skowness at one phase of the study tured out to be unusually complicated involving the asymptotic expressions for variance and bias. When these were identified a much simpler compact expression appeared which we now describe. The work is a much improved treatment of the subject described in Shenton and Bowman (Mariunm likelihood estimation in small samples, Griffin. 1977).
The turbulent/non-turbulent interface in an inclined dense gravity current

Abstract We present an experimental investigation of entrainment and the dynamics near the turbulent/non-turbulent interface in a dense gravity current. The main goal of the study is to investigate changes in the interfacial physics due to the presence of stratification and to examine their impact on the entrainment rate. To this end, three-dimensional data sets of the density and the velocity fields are obtained through a combined scanning particle tracking velocimetry/laser-induced fluorescence approach for two different stratification levels with inflow Richardson numbers of $\mathit{Ri}_{0}=0.23$ and $\mathit{Ri}_{0}=0.46$ , respectively, at a Reynolds number around $\mathit{Re}_{0}=3700$ . An analysis conditioned on the instantaneous position of the turbulent/non-turbulent interface as defined by a threshold on enstrophy reveals an interfacial region that is in many aspects independent of the initial level of stratification. This is reflected most prominently in matching peaks of the gradient Richardson number $\mathit{Ri}_{g}\approx 0.1$ located approximately $10{\it\eta}$ from the position of the interface inside the turbulent region, where ${\it\eta}=({\it\nu}^{3}/{\it\epsilon})^{1/4}$ is the Kolmogorov scale, and ${\it\nu}$ and ${\it\epsilon}$ denote the kinematic viscosity and the rate of turbulent dissipation, respectively. A possible explanation for this finding is offered in terms of a cyclic evolution in the interaction of stratification and shear involving the buildup of density and velocity gradients through inviscid amplification and their subsequent depletion through molecular effects and pressure. In accordance with the close agreement of the interfacial properties for the two cases, no significant differences were found for the local entrainment velocity, $v_{n}$ (defined as the propagation velocity of an enstrophy isosurface relative to the fluid), at different initial stratification levels. Moreover, we find that the baroclinic torque does not contribute significantly to the local entrainment velocity. Comparing results for the surface area of the convoluted interface to estimates from fractal scaling theory, we identify differences in the interface geometry as the major factor in the reduction of the entrainment rate due to density stratification.
Haze and Fog Aerosol Distributions

Abstract Spectral attenuation measurements through haze and fogs are used to synthesize aerosol distributions characteristic of the attenuating medium. Twelve fog drop-size distributions have been averaged into two general types of fogs for comparison with measured fog drop-size distributions and with a distribution predicted by theory. Seven time-phased fog drop-size distributions are used to illustrate the phenomena of droplet growth and fog degeneration. Finally, an empirical relationship between liquid water content and visual range is presented.
Robustness analysis of the Zhang neural network for online time-varying quadratic optimization

A general type of recurrent neural network (termed as Zhang neural network, ZNN) has recently been proposed by Zhang et al for the online solution of time-varying quadratic-minimization (QM) and quadratic-programming (QP) problems. Global exponential convergence of the ZNN could be achieved theoretically in an ideal error-free situation. In this paper, with the normal differentiation and dynamics-implementation errors considered, the robustness properties of the ZNN model are investigated for solving these time-varying problems. In addition, linear activation functions and power-sigmoid activation functions could be applied to such a perturbed ZNN model. Both theoretical-analysis and computer-simulation results demonstrate the good ZNN robustness and superior performance for online time-varying QM and QP problem solving, especially when using power-sigmoid activation functions.
Spectropolarimetry of 'narrow-line' Seyfert 1 galaxies

Spectropolarimetry is used here to investigate the properties of 'narrow-line' Seyfert 1 galaxies. In general, continuum polarization arising to the blue and/or the lack of significant broadening of the polarized emission lines points to dust reflection as the primary polarigenic mechanism. There is some evidence that the dust is associated with the forbidden O III-emitting region. Where line polarizations can be compared, H-beta is found to be more highly polarized than the forbidden O III 4959, 5007 A lines A, demonstrating that these lines come from spatially distinct within the nucleus. Simultaneous spectrophotometry obtained by the spectropolarimetry is used to demonstrate that X-ray selected Seyfert 1s show significantly smaller H-beta equivalent widths than a sample of optically selected narrow-line 1s and Seyfert 2s. 51 refs.
Monotone Approximation by Polynomials

We prove Jackson type estimates for the approximation of monotone functions by monotone polynomials. The results are given in terms of the modulus of continuity of $f^{(k)} $ , for any $k \geqq 0$. The estimates are of the same order as for the unconstrained approximation by polynomials.
Oﬀ-shell N = 2 linear multiplets in ﬁve dimensions

: We present a superconformal tensor calculus for an arbitrary number of ﬁve dimensional N = 2 linear multiplets. We also demonstrate how to construct higher derivative invariants, and produce higher order supersymmetric oﬀ-diagonal models. Finally, we show the procedure required for the derivation of the supersymmetric completion of the non-Abelian F 4 action.
Observational Evidence for Asymmetric Inertial Instability

Abstract We present a detailed analysis of a mesoscale circulation phenomenon that appeared on satellite images as a group of propagating cloud wavelets. These wavelets developed on the anticyclonic side of a strong, upper-level subtropical jet in a region of negative potential vorticity (P). During their lifetime, the wavelets were located over the North American synoptic sounding network; the meteorological conditions surrounding their occurrence are examined. We investigate the various physical mechanisms that may have been responsible for generating the observed cloud wavelets. In consideration of the time scale of the wavelets and their proximity to the region where P < 0, inertial instability appears to be the most likely dynamical mechanism for explaining their existence. Using hourly satellite images, we determined that the wavelets propagated downstream at a phase speed 25 m s−1 slower than the maximum wind speed of the jet with life cycles of 4–5 h, horizontal wavelengths of ∼400 km, and periods.
Evidence for pulsed 1000 GeV gamma-rays from the Crab pulsar

On a detecte une emission faible periodique et persistante de Rγ≤1000 GeV provenant de PSR 0531, en 1982-83. La courbe de lumiere de l'emission Rγ de 100 a 1000 GeV montre un pic etroit en coincidence avec la pulsation principale aux autres longueurs d'onde
Approximate Analysis of Simply Supported Composite Beams with Partial Interaction

An approximate analysis method was presented for the analysis and design of a simply supported composite beam with partial interaction. To solve the governing differential equation in linear elastic partial interaction theory, the internal axial force was approximated by Fourier series. In case studies, the internal axial force, slip and displacement of the beam were obtained for some load cases such as temperature load, end moment, point load and uniformly distributed load. From the study for convergence of the approximate solution, the relative error for the displacement was converged below about 0.1% at more than the fifth order of Fourier series. This method can be applied to arbitrary loading conditions. Also, the results are sufficiently accurate for determining the behavior of the composite beam with partial interaction for the design purpose.
Evolution of galaxies in clusters. I. ISIT photometry of Cl 0024 + 1654 and 3C 295

First results are presented of a program of two-color photometry of very distant (z greater than or equal to 0.4) clusters of galaxies, using the KPNO ISIT vidicon. It is demonstrated that the ISIT system is capable of accurate photometry of faint (V approx. 23.5) galaxies in exposure times of about 1 hour on a 2.1-m telescope. Photometry is presented for two clusters, Cl 0024 + 1654 (z = 0.39) and the cluster around 3C 295 (z = 0.46). Both clusters are rich, centrally condensed systems similar to the Coma cluster. However, in contrast to nearby clusters of this type, which contain only elliptical and S0 galaxies, between one-third and one-half of the galaxies in these two distant clusters have the colors of spiral galaxies. The possible implications of this result for the evolutionary history of S0 galaxies are discussed. 17 figures, 3 tables.
Fluoride-added Pr–Fe–B die-upset magnets with increased electrical resistivity

This work reports the effect of NdF3, DyF3, and CaF2 additions on the electrical resistivity and magnetic properties of Pr–Fe–B hot-pressed and die-upset permanent magnets. Composite magnets were synthesized from ground Pr14.5Fe79. 5B6 melt-spun ribbons blended with 5wt% of fluoride fine powders and consolidated by hot pressing at 650°C, followed by die upsetting at 800°C. While CaF2 is stable at the processing temperatures, the rare earth atoms separate from their fluorides to a certain degree with the assistance of the Pr-rich phase from the magnet matrix. Addition of fluorides increased the resistivity of the hot-pressed specimens by more than 200%. The resistivity of the die-upset specimens measured perpendicularly to the direction of the applied pressure, which is also the direction of magnetization, is, however, only slightly increased compared to the magnet counterparts without the fluoride addition. The intrinsic coercivity of Pr14.5Fe79. 5B6 die-upset specimens is increased from 14.5kOe to 15.3, 17.
The Eyewall-Penetration Reconnaissance Observation of Typhoon Longwang (2005) with Unmanned Aerial Vehicle, Aerosonde

Abstract In this paper, a successful eye-penetration reconnaissance flight by an unmanned aerial vehicle, Aerosonde, into Typhoon Longwang (2005) and the preliminary analyses of the collected data are presented. The 10-h flight is diagnosed through four flight legs. The wind field measured along flight leg 1 provides the tangential and radial wind profiles from the outer perimeter into the eye of the typhoon at the 700-hPa layer. A vertical sounding was taken in the eye along flight leg 2 and the derived surface pressure in the eyewall is close to the estimates made by the local weather agencies. Along flight leg 3, the strongest winds during the whole flight mission were measured. These in situ wind measurements by Aerosonde are consistent with the winds observed by the Hua-lien Doppler weather radar. The maximum 10-min (1 min) wind along flight leg 3 when Aerosonde was flying around the eyewall region is 58.6 m s−1 (62 m s−1). The maximum sustained surface wind derived from this maximum wind speed is al.
Health Service Utilization and Insurance Coverage: A Multivariate Probit Analysis

Abstract A computationally practical form of probit analysis for multiple response variables was applied to data on health service utilization as it relates to type of supplemental insurance coverage and other demographic covariates in a sample of 4,658 individuals over age 65 on Medicare. The quantal response variables comprised use of five health services: Medical provider visit, hospital outpatient visit, emergency room visit, hospital inpatient stay, and home health care visit. An individual could use any or all of these services. Supplemental insurance coverage was categorized as Medicaid, employer-related private insurance, and privately purchased insurance, and any combination of these insurance coverages was possible. Covariates included health status, education, urban location, race, sex, marital status, employment status, age, and income. The multivariate probit model estimates association between insurance coverage variables and health service utilization patterns jointly for the five health se.
Elastic constants of nonmetamict zirconium silicate

Two independent reports in the literature for the elastic constants of zircon (zirconium silicate) are in disagreement by an order of magnitude and are reported without specifying the conditions of the mineralogical specimens. However, natural zircon crystals frequently contain uranium and thorium atoms as an impurity so that zircon can exist in a metamict (radiation damaged) condition. A redetermination of the elastic constants has been carried out on small synthetic crystals and on high‐purity natural single crystals of nonmetamict zircon of lattice parameters ao = 6.606(2) A, co = 5.980(2) A by ultrasonic pulse superposition and also by phase comparison methods. The values in 1012 dyn/cm2 are c11 = 4.237, c33 = 4.900, c44 = 1.136, c66 = 0.485, c12 = 0.703, and c13 = 1.495. The estimated uncertainty in the measurements are 0.4% for c11, c33, c44, and c66, and 3% for c12 and c13. Wave velocity measurements have also been carried out on a metamict zircon crystal (density 4.531 g/cm3) and it is shown that .
X-ray and gamma-ray emission from millisecond pulsars

We present a self-consistent model to describe X-ray and γ -ray emission from millisecond pulsars (MSPs). The X-rays of MSPs are produced by the backflow of primary charged particles from the outer gap and most likely consist of three components, two thermal components and one power law component if there is a strong multipole magnetic field on the stellar surface. The backflow of ultra-relativistic particles emits photons with energies about several tens of GeV via curvature radiation. These photons cause an electromagnetic cascade about 2–3 stellar radii above the polar cap. The synchrotron radiation of these cascade e$^\pm$ pairs produces hard X-rays with a power law index ~$ 1.5$. Near 10 5 cm above the stellar surface, the primary charged particles encounter the strong surface magnetic field, which alters the local radius of curvature greatly, and they quickly loose more than half of their remaining energies to curvature radiation. These curvature photons heat up the polar cap area with a radius ~ 10 5 cm, which produce the softer thermal X-ray component. Finally, the primary charged particles deposit their remaining energies in a much smaller polar cap area, which corresponds to the footprints of outer gap and produce the medium hard X-ray component. γ -rays are produced in the outer gap through synchro-curvature radiation. We have applied this model to the MSPs which emit pulsed X-rays and likely γ -rays such as PSR J0437-4715, PSR J2124-3358, PSR J0218+4232 and PSR B1821-24. Our results give an agreement between predicted spectrum and the observed spectrum of MSP emission.
The luminosity scale of RR Lyrae stars with the Baade-Wesselink method. II. The absolute magnitudes of 13 field RR Lyrae stars

The surface brightness version of the Baade-Wesselink method has been applied to 13 field RR Lyrae stars to derive their absolute magnitudes from the photometry and radial velocities presented in a previous paper. Using static model atmospheres to provide metallicity- and gravity-dependent color-temperature transformations, it is found that the RR Lyrae temperature scale can be relatively well defined using the infrared color index V-K except for a small phase interval where strong atmospheric acceleration and shock waves are present, while the temperatures determined from bluer color indices are systematically overestimated. The results show a clear correlation between the luminosities of the RR Lyraes and their metallicities. 99 refs.
Stability of Conjugate Gradient and Lanczos Methods for Linear Least Squares Problems

{The conjugate gradient method applied to the normal equations ATAx=ATb (CGLS) is often used for solving large sparse linear least squares problems. The mathematically equivalent algorithm LSQR based on the Lanczos bidiagonalization process is an often recommended alternative. In this paper, the achievable accuracy of different conjgate gradient and Lanczos methods in finite precision is studied. It is shown that an implementation of algorithm CGLS in which the residual sk=AT(b-Axk) of the normal equations is recurred will not in general achieve accurate solutions. The same conclusion holds for the method based on Lanczos bidiagonalization with starting vector ATb. For the preferred implementation of CGLS we bound the error ||r-rk|| of the computed residual rk. Numerical tests are given that confirm a conjecture of backward stability. The achievable accuracy of LSQR is shown to be similar. The analysis essentially also covers the preconditioned case.
√n-CONSISTENT ESTIMATION IN A RANDOM COEFFICIENT AUTOREGRESSIVE MODEL

Summary This paper deals with √n-consistent estimation of the parameter μ in the RCAR(l) model defined by the difference equation Xj=(μ+Uj)Xj-l+ej (je Z), where {ej: je Z} and {Uj: je Z} are two independent sets of i.i. d. random variables with zero means, positive finite variances and E[(μ+U1)2] < 1. A class of asymptotically normal estimators of μ indexed by a family of bounded measurable functions is introduced. Then an estimator is constructed which is asymptotically equivalent to the best estimator in that class. This estimator, asymptotically equivalent to the quasi-maximum likelihood estimator derived in Nicholls & Quinn (1982), is much simpler to calculate and is asymptotically normal without the additional moment conditions those authors impose.
State-of-polarization Encoding for Optical Code-Division Multiple-Access Networks

In this paper we propose the use of the State of Polarization (SOP) encoding in order to realize an optical CDMA system. The SOP of the optical beam is alternately switched between two orthogonal SOPs according to a given codeword. Multiple users can use the network simultaneously each with a distinct codeword. Gold and Hadamard codes can be applied with minimal interference in the latter case. The optical beam power is constant in such case, therefore, self-phase and cross-phase effects can be eliminated.
SINGULAR QUADRATIC FUNCTIONALS OF n DEPENDENT VARIABLES(

Introduction. In this paper singular quadratic functionals of n dependent variables are systematically studied. Necessary and sufficient conditions for the existence of a minimum are given, generalizing the results of Morse and Leighton [6]. The study of principal quadratic functionals of n dependent variables is undertaken. A necessary condition is proved and sufficient conditions are obtained for certain cases. Finally, an oscillation theorem is given for systems of second-order linear differential equations. We shall make the usual conventions regarding notation. A repeated subscript indicates summation. We shall use the symbol (*) to indicate the transpose of a matrix or vector. In general capital letters indicate matrices, and we shall employ the notation A = || a,j || for a matrix when necessary. The determinant of a matrix A will be written det A. The notation I a I will be reserved to indicate the absolute value of a number a. I. The functional. Let f(x,y,y') = y*'(x)R(x)y'(x) + 2y*'(x)Q(x)y(x) (1.1) + y*(x)P(x)y(x), where R(x), Q'(x), and P(x) are symmetric matrices continuous in the real variable x on [a, oo), and R(x) is positive definite for any fixed x on [a, oo). We consider the functional
Modeling the role of inherent spectral change in vowel identification

Statistical analysis of F1 and F2 measurements from nucleus and offglide sections of isolated Canadian English vowels shows significant formant frequency change not only for the ‘‘phonetic diphthongs’’ /e/ and /o/, but also for the ‘‘monophthongs’’ /ι/, /q/, and /1/. In a perceptual experiment, brief sections were extracted from ‘‘nucleus’’ and ‘‘offglide’’ portions of naturally produced vowels. Two sections from each vowel were presented to listeners in each of three conditions: (1) natural order (nucleus followed by offglide); (2) repeated nucleus (nucleus followed by itself); and (3) reverse (offglide followed by nucleus). Listeners’ error rates for the natural order condition were comparable to those for unmodified full vowels (averaging 14% and 13%, respectively). Significantly higher error rates were found for the repeated nucleus (32%) and reverse (38%) conditions. Observed confusion matrices were strongly correlated with predictions from a pattern recognition model incorporating the formant measur.
Diffuse Cosmic Gamma Radiation Measured by HEAO 1

The High Energy Astronomical Observatory 1 (HEAO 1) contained as one of its instruments the UCSD/MIT hard X-ray and gamma-ray instrument, a complex of actively shielded scintillation counters that operated over the nominal 10 keV to 10 MeV range. The two medium-energy detectors (MEDs) employed in this investigation covered the range 80 keV-2 MeV, had a geometrical area of 43 cm2, and were collimated to a circular field of view of 17° FWHM. During a period of operation starting in 1978 April, these detectors were operated in a manner designed to provide a precise measure of the diffuse cosmic background gamma-ray flux. Previous measurements of the spectrum in this range were not of sufficient precision to distinguish between various models explaining the hard X-ray background either as an ensemble of discrete sources or due to a global effect at cosmological distances. The detectors could be alternately blocked or unblocked with a moveable shutter of CsI, which could be operated in an active anticoincidence mode or as a passive shield. Data taken in these various modes and analyzed with respect to the varying radiation environment of the 23° inclination 400 km circular orbit permitted separation of various background effects that have plagued previous measurements of this radiation using scintillation spectrometers. Over the ~80-400 keV band, systematic errors were small and correctable, with a resulting spectrum fitted by a power law of dN/dE = (2.62 ± 0.05) × 10-3(E/100 keV)-(2.75±0.08 photons cm-2 s-1 keV-1 sr-1. This fit, in general agreement with previous results in this energy range, joins smoothly with measurements at lower energies, and when extrapolated to higher energies, it agrees with the recently reported COMPTEL results at energies above 2 MeV obtained on the Compton Gamma Ray Observatory. The accompanying demonstration of the experimental difficulties associated with scintillation spectrometer measurements of the diffuse cosmic background provides significant clarification of the observational status of this important measurement. When account is taken of measurements with possible local background estimation uncertainties, the spectrum between ~200 keV and ~50 MeV appears more simplified than previous estimates.