Miracle-dz/UniFAR-FTUs huggingface dataset:
Bayesian analysis of the multivariate geographical distribution of the socio‐economic environment in England

In this paper we analyse the geographical distribution of the Indices of Deprivation 2004, a set of seven area‐based indices measuring multiple dimensions of socio‐economic status (SES) related to income, employment, education, health, access to services and housing, crime, and living environment in England at district level. We first study all the seven SES ‘domains’ separately using spatial hierarchical models to assess the level of underlying geographical structure in each of them. We then explore their joint relationships using a spatial factor model that extracts the information common and specific to the income, employment and education domains and regress the other domains on the extracted components. We use Bayesian inference throughout. Results show that all seven domains present strong spatial structure. The income, employment, education and health domains largely share the same information, which moderately overlaps with the crime and environment domains. The domain on access to services and housing is quite different from the others. The geographical patterns found in the latent common and specific factors are however difficult to interpret without further complementary information. Further investigation is required to identify plausible causal processes related to current economic and regional policies, and also to historic factors and their long‐lasting socio‐economic legacy. Copyright © 2007 John Wiley & Sons, Ltd.
Hubble Space Telescope WFPC2 Imaging of M16: Photoevaporation and Emerging Young Stellar Objects

We present Hubble Space Telescope WFPC2 images of elephant trunks in the H II region M16. There are three principle results of this study. First, the morphology and stratified ionization structure of the interface between the dense molecular material and the interior of the H II region is well understood in terms of photoionization of a photoevaporative flow. Photoionization models of an empirical density profile capture the essential features of the observations, including the extremely localized region of [S II] emission at the interface and the observed offset between emission peaks in lower and higher ionization lines. The details of this structure are found to be a sensitive function both of the density profile of the interface and of the shape of the ionizing continuum. Interpretation of the interaction of the photoevaporative flow with gas in the interior of the nebula supports the view that much of the emission from H II regions may arise in such flows. Photoionization of photoevaporative flows may provide a useful paradigm for interpreting a wide range of observations of H II regions. Second, we report the discovery of a population of small cometary globules that are being uncovered as the main bodies of the elephant trunks are dispersed. Several lines of evidence connect these globules to ongoing star formation, including the association of a number of globules with stellar objects seen in IR images of M16 or in the continuum HST images themselves. We refer to these structures as evaporating gaseous globules, or "EGGs. " These appear to be the same type of object as the nebular condensations seen previously in M42. The primary difference between the two cases is that in M16 we are seeing the objects from the side, while in M42 the objects are seen more nearly face-on against the backdrop of the ionized face of the molecular cloud. We find that the "evaporating globule" interpretation naturally accounts for the properties of objects in both nebulae, while avoiding serious difficulties with the competing "evaporating disk" model previously applied to the objects in M42. More generally, we find that disk-like structures are relatively rare in either nebula. Third, the data indicate that photoevaporation may have uncovered many EGGs while the stellar objects in them were still accreting mass, thereby freezing the mass distribution of the protostars at an early stage in their evolution. We conclude that the masses of stars in the cluster environment in M16 are generally determined not by the onset of stellar winds, as in more isolated regions of star formation, but rather by disruption of the star forming environment by the nearby O stars.
Meta-typological distributions

Abstract The paper is the first attempt to study the quantitative representation of language type in the world′s languages as a random variable, that is, to describe the a priori probability p(x) of a randomly selected language type being represented by x languages. The major goal of this approach is to understand the general properties of cross-linguistic distributions, which might then be used as the standard of comparison for specific typological studies. Using the WALS database of language types, I show that the number of representatives of a language type can be approximated by a Pareto (power-law) distribution.
Isometric Embedding of Riemannian Manifolds into Euclidean Spaces

This is a review of differential geometry results pertaining to the problem of embedding curved space-time in a pseudo-Euclidean space. DOI: https://doi.org/10.1103/RevModPhys.37. 201.2  ©1965 American Physical Society AUTHORS & AFFILIATIONS AVNER FRIEDMAN Department of Mathematics, Northwestern University, Evanston, Illinois  REFERENCES (SUBSCRIPTION REQUIRED) CLICK TO EXPAND  Issue Vol. 37, Iss. 1 — January March 1965 Reuse & Permissions Isometric embedding of Riemannian manifolds into Euclidean spaces This site uses cookies. To find out more, read our Privacy Policy. I Agree Access Options Buy Article » Get access through a U.S. public or high school library » Log in with a username/password provided by your institution » Enter your email Sign up to receive regular email alerts from Reviews of Modern Physics Sign Up More Links AUTHORS REFEREES LIBRARIANS STUDENTS APS MEMBERS Privacy Policies Contact Information Feedback Global isometric embedding of a Riemannian 2-manifold with nonnegative curvature into a Euclidean 3-space. Kazuo Amano. More by Kazuo Amano. Global isometric embedding of a Riemannian 2-manifold with nonnegative curvature into a Euclidean 3-space. J. Differential Geom. 34 (1991), no. 1, 49--83. doi:10.4310/jdg/1214446990. https://projecteuclid.org/euclid.jdg/1214446990. On critical Riemannian metrics for a curvature functional on 3-manifolds Katagiri, Minyo, Proceedings of the Japan Academy, Series A, Mathematical Sciences, 2002. Topology of Riemannian submanifolds with prescribed boundary Alexander, Stephanie, Ghomi, Mohammad, and Wong, Jeremy, Duke Mathematical Journal, 2010. + See more. More like this. The Nash embedding theorems (or imbedding theorems), named after John Forbes Nash, state that every Riemannian manifold can be isometrically embedded into some Euclidean space. Isometric means preserving the length of every path. For instance, bending without stretching or tearing a page of paper gives an isometric embedding of the page into Euclidean space because curves drawn on the page retain the same arclength however the page is bent. 53C15, 53C20 VOL. 46 (1992) [177178] ISOMETRIC IMMERSION OF A COMPACT RIEMANNIAN MANIFOLD INTO A EUCLIDEAN SPACE SHARIEF DESHMUKH We show that an isometric immersion of an n-dimensional compact Riemannian manifold of non-negative Ricci curvature with scalar curvature always less than n(n — 1)A~* into a Euclidean space of dimension n + 1 can never be. [2] H. Jacobowitz, 'Isometric embedding of a compact Riemannian manifold into Euclidean space', PTOC. Amer. Math. ISSN 1539-0756 (online), 0034-6861 (print). ©2019 American Physical Society. All rights reserved. Reviews of Modern PhysicsTM is a trademark of the American Physical Society, registered in the United States, Canada, European Union, and Japan. The APS Physics logo and Physics logo are trademarks of the American Physical Society. Information about registration may be found here. Use of the American Physical Society websites and journals implies that the user has read and agrees to our Terms and Conditions and any applicable Subscription Agreement.
Statistical-band-model analysis and integrated intensity for the 21.8 micrometer bands of HNO3 vapor

The 21.8 μm absorption bands of HNO3 vapor were measured at 40°C. Statistical-band-model analysis of the data resulted in spectral-band-model parameters and yielded an integrated intensity of 393 ± 15% (cm−2 atm−1) at 40°C between 390 and 502 cm−1.
Parameter estimation of piecewise Hammerstein systems

The system is often described as a series of blocks linked together in non-linear system identification. Such block-oriented models are built with static non-linear subsystems and linear dynamic systems. This paper deals with the parameter estimation of Hammerstein systems with piecewise non-linearities, which is a blocked-oriented model where a static non-linear blocking is followed by a linear dynamic system. The basic idea is as follows. The key term separation technique is applied initially, and then a corresponding auxiliary model is constructed. Hence, the identification problem of the system is converted to a non-linear function optimization problem over parameter space. Once again, the estimates of all the parameters are obtained by a proposed particle swarm optimization algorithm. Finally, compared with the existing methods, the simulation results confirm that the presented method is valid. Moreover, the presented method is further extended to estimate Hammerstein systems with discontinuity non-linearities.
Wavelet and FFT Based Image Denoising Using Non-Linear Filters

We propose a stationary and discrete wavelet based image denoising scheme and an FFTbased image denoising scheme to remove Gaussian noise. In the first approach, high subbands are added with each other and then soft thresholding is performed. The sum of low subbands is filtered with either piecewise linear (PWL) or Lagrange or spline interpolated PWL filter. In the second approach, FFT is employed on the noisy image and then low frequency and high frequency coefficients are separated with a specified cutoff frequency.Then the inverse of low frequency components is filtered with one of the PWL filters and the inverse of high frequency components is filtered with soft thresholding. The experimental results are compared with Liu and Liu's tensor-based diffusion model (TDM) approach.
Diffusion in a dilute polydisperse system of interacting spheres

When m different species of small particles are dispersed in fluid the existence of a (small) spatial gradient of concentration of particles of type j is accompanied, as a consequence of Brownian motion of the particles, by a flux of particles of type i. The flux and the gradient are linearly related, and the tensor diffusivity Dij is the proportionality constant. When the total volume fraction of the particles is small, Dij is approximately a linear function of the volume fractions ϕ1, ϕ2, …s, ϕm, with coefficients which depend on the interactions between pairs of particles. The complete analytical expressions for these coefficients given here for the case of spherical particles are a linear combination of the second virial coefficient for the osmotic pressure of the dispersion (measuring the effective force acting on particles when there is a unit concentration gradient) and an analogous virial coefficient for the bulk mobility of the particles. Extensive calculations of the average velocities of the different species of spherical particles in a sedimenting polydisperse system have recently been published (Batchelor & Wen 1982) and some of the results given there (viz. those for small Péclet number of the relative motion of particles) refer in effect to the bulk mobilities wanted for the diffusion problem. It is thus possible to obtain numerical values of the coefficient of ϕk in the expression for Dij, as a function of the ratios of the radii of the spherical particles of types i, j and k. The numerical values for ‘hard’ spheres are found to be fitted closely by simple analytical expressions for the diffusivity; see (4.6) and (4.7). The dependence of the diffusivity on an interparticle force representing the combined action of van der Waals attraction and Coulomb repulsion in a simplified way is also investigated numerically for two species of particles of the same size. The diffusivity of a tracer particle in a dispersion of different particles is one of the many special cases for which numerical results are given; and the result for a tracer ‘hard’ sphere of the same size as the other particles is compared with that found by Jones & Burfield (1982) using a quite different approach.
Identification and Verification of Hierarchy of DFIG Converter Controls for Power System Damping

Abstract This article employs two decomposition techniques and the residue principles to determine the order of the converter controls of a doubly fed induction generator (DFIG) in terms of providing system damping. The dynamic model of the various components of the DFIG system—the wind turbine, induction generator, converter system, the load and transmission network are derived and 4 converter controls identified. The hierarchy analysis demonstrates that out of 4 converter controls the magnitude of the rotor applied voltage is the most effective one. The finding was verified by simulating the system through both lead-lag as well as proportional-integral (PI) controller designs, the controller parameters being found through the residue principle. Simulation studies on the doubly fed generator system show that both the controller designs provide good damping to the system, the PI control being slightly superior. The controlled rotor voltage was observed to be able to avert voltage collapse in the system arising in the event of severe disturbance conditions.
Pair-production discharges above pulsar polar caps.

It is shown that an electron-positron pair plasma will generally be created above a positively charged polar cap, in various models for ion flow and pair production. A potential drop above a polar cap may arise either from (A) the inertia of freely released ions in a space-charge-limited flow, or from (B) surface binding of ions leading to gap formation. Pair-production discharges which limit this potential drop may arise from (1) Sturrock-type pair-production discharges with pair creation in the stellar magnetic field, or (2) pair production by thermal X-rays from the polar cap surface in the Coulomb field of relativistic ions or electrons and positrons accelerated through the discharge region. In all cases the properties of the outward moving electron-positron pair plasma are similar.
Breath figures: Self-organizing masks for the fabrication of photonic crystals and dichroic filters

Controlled condensation of water vapor on a nonpolar liquid polymer film leads to the formation of submicrometer arrays of water droplets. Dissolution of a small amount of a polymer surfactant in the volatile liquid prevents the drops from coalescing and stabilizes their hexagonal arrangement. When subsequently the solvent and the water evaporate a solid polymer film patterned with hexagonally ordered holes remains—similar in shape to a honeycomb pattern. The hole size and the polydispersity are controlled by the solvent type, the flow rate of the condensing vapor, and the polymer concentration. The pattern is used as a lithographic mask to structure semiconductor surfaces. To this end, metal is deposited on the prestructured surface and subsequently lifted off to create two complementary structures: an array of metal disks on the semiconductor and a metal network. The lateral periodicity of the patterns can be varied between 300nm and several micrometers covering macroscopic areas (∼1cm2). Employing the metallic disk pattern as a mask in a plasma dry-etching process we have fabricated two-dimensional photonic crystals with small lattice constants in silicon. We have also used the complementary metal net for the production of metallic dichroic filters. The thin metal net acts as an optical short-pass in the infrared region of the spectrum due to its small lateral structure dimensions. The optical transmission of the dichroic filters is measured and simulated by a model calculation.Controlled condensation of water vapor on a nonpolar liquid polymer film leads to the formation of submicrometer arrays of water droplets. Dissolution of a small amount of a polymer surfactant in the volatile liquid prevents the drops from coalescing and stabilizes their hexagonal arrangement. When subsequently the solvent and the water evaporate a solid polymer film patterned with hexagonally ordered holes remains—similar in shape to a honeycomb pattern. The hole size and the polydispersity are controlled by the solvent type, the flow rate of the condensing vapor, and the polymer concentration. The pattern is used as a lithographic mask to structure semiconductor surfaces. To this end, metal is deposited on the prestructured surface and subsequently lifted off to create two complementary structures: an array of metal disks on the semiconductor and a metal network. The lateral periodicity of the patterns can be varied between 300nm and several micrometers covering macroscopic areas (∼1cm2). Employing the .
Hydrodynamic excitations in a Bose-Einstein condensate

The field of Bose-Einstein condensation (BEC) in dilute atomic gases provides a fruitful playground to test well-developed theories of quantum fluids. Research using BECs can address open questions relating to the many-body aspects of two-component quantum liquids, namely the interaction between the hydrodynamic normal and the superfluid component at finite temperatures. After the first realization of BEC some pilot experiments have been carried out, but detailed experiments are missing. This has to be compared to the case of liquid helium II, where many experiments since the 1950s have added to our understanding of novel phenomena in quantum liquids, like collective excitations, first and second sound, and others. One of the drawbacks of liquid helium is that the interactions are so strong that a clear distinction between the two components is difficult and the interpretation of the phenomena remains ambiguous. Most experimental studies of dilute Bose-Einstein condensed gases use clouds, which are in the collisionless regime. The reason for the lack of detailed experiments in BECs to study quantum liquids and in particular the hydrodynamical aspects of it, is the limited number of atoms (typically 1--10 million) in the experiments leaving the thermal atoms virtually collisionless. Efforts to decrease the mean free path by increasing the confinement limits the lifetime of the sample, since the density is limited by three-body decay. Experiments on dilute clouds of cold atoms are generally conducted in highly asymmetric traps. In these elongated, cigar-shaped geometries the mean free path of the atoms can become much shorter than the size of the cloud in the long, axial direction, but at the same time exceeds the size in the other, radial directions. In this so-called hydrodynamic-collisionless regime the system can be considered radially collisionless and axially hydrodynamic. In our setup we have created BECs containing up to 300 million sodium atoms by evaporation of atoms in an axially strongly decompressed trap with an aspect ratio of 1:65. Hot atoms created in three-body collisions are able to leave the sample in this highly asymmetric trap, before they can heat other atoms in an avalanche. The sample is axially hydrodynamic, but due to the large aspect ratio collisionless in the radial direction. Such samples are ideal for the observation of the interaction between the superfluid and normal fluid component of the cloud. In this thesis we describe the setup which is used to reach the hydrodynamic regime and we describe a novel implementation of the well-known phase contrast imaging technique. Next, we study collective excitations in the crossover from the collisionless toward the hydrodynamic regime, we determine the heat conduction in a cold, hydrodynamic thermal cloud and observe the propagation of a thermal wave in the two-fluid regime. Furthermore, we study the friction between the superfluid and normal fluid component of the cloud. In the final chapters of this thesis we study the propagation of second sound, as well as the formation and propagation of shock waves.
A nonlinear normalization method for handprinted kanji character recognition-line density equalization

A nonlinear normalization method called the line density equalization is proposed in which a resampling is done so as to equate the product of a local line density and a (variable) sampling pitch. Consequently, the line density in the space is homogenized, the efficiency of utilization of the space is increased, and a stable normalization is obtained for partially irregular shape variations. The method was applied to handprinted kanji character recognition, and its effectiveness was demonstrated. <<ETX>>
X-ray pinhole camera resolution and emittance measurement

Third generation synchrotron light sources are characterized by a low emittance and a low emittance coupling. Some light sources are already operating with extremely low coupling close to 0.1%. Measurement of the transverse beam size is generally used to measure the emittance and the coupling. To this end, several systems are currently used and an x-ray pinhole camera is one of them. In this paper we derive the point spread function of the x-ray pinhole camera both analytically and numerically using the Fresnel diffraction integral and taking into account the broadband spectrum of the bending magnet source, and we show that an optimized design allows the measurement of extremely small vertical beam sizes below $5\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. The point spread function of several scintillator screens is also measured, and it shows that the contribution of the diffraction and the screen point spread functions have to be taken into account for an accurate measurement of a low coupling. Finally, we show measurements of the vertical beam sizes as small as $6\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ for our nonoptimized setup.
Mixed convection along a vertical cone for fluids of any Prandtl number: case of constant wall temperature

An analysis of steady laminar mixed convection boundary layer flow along a vertical cone of constant wall temperature is presented. A mixed convection parameter ξ, as proposed by Lin and Chen, is used to serve as a controlling parameter that determines the relative importance of the forced and the free convection flows. New coordinates and dependent variables are then defined in terms of ξ, so that the transformed non‐similar boundary layer equations give computationally efficient numerical solutions which are valid over the entire range of mixed convection flow from the forced convection limit to the free convection limit for fluids of any Prandtl number. The effects of the mixed convection parameter ξ and the Prandtl number Pr on the velocity and temperature profiles as well as on the skin friction and heat transfer coefficients are shown for both cases of buoyancy assisting and buoyancy opposing flow conditions.
Serially correlated variables in dynamic, discrete choice models

This paper discusses the problems that are encountered when dynamic, discrete choice models are specified with continuous, serially correlated state variables. A variety of approximation methods that can deal with these problems is examined, and an empirical example that allows continuous variables to be serially correlated is presented. Copyright © 2000 John Wiley & Sons, Ltd.