Miracle-dz/UniFAR-FTUs huggingface dataset:
The Wigner angle as an anholonomy in rapidity space

A product of two non-collinear boosts (i.e., pure Lorentz transformations) can be written as the product of a boost and a rotation, the angle of rotation being known as Wigner’s angle. This paper demonstrates how the Wigner angle and final boost parameters can be calculated simply in terms of the initial boost parameters using hyperbolic trigonometry. It also demonstrates that the Wigner angle is the (negative) area of a rapidity triangle composed of the two non-collinear boosts and their resultant.
Analysis of swimming three-dimensional waving plates

The three-dimensional waving plate theory is developed to investigate the swimming performance of fish undulatory motion. In particular, the propulsive effectiveness is discussed. The unsteady potential flow over model rectangular and triangular flexible plates performing a motion which consists of a progressing wave with variable amplitudes is calculated by the vortex ring panel method. It is found that the undulatory motion can reduce three-dimensional effects. It is this important hydrodynamic phenomenon that may be one of the main reasons why such undulation is widely used as the swimming method by a large number of aquatic animals. When the span of the undulating plate is nearly unchanged and the wave amplitude is constant or increases slightly along the chord, and the wavelength is close to the body length, theoretical results show that the swimming performance is best and the flow around the plate has a quasi-two-dimensional property. This swimming method may be observed in many fishes, especially those with an anguilliform mode of propulsion. The modification of the anguilliform mode of propulsion to the carangiform mode is also discussed. It is confirmed that the pronounced necking of the body anterior to the tail, which acts to improve the propulsive performance, is a major morphological adaptation of fishes using the carangiform mode, in which the characteristic nature of flexural movement confined to the rear part of the body is that the amplitude of undulation increases posteriorly and no complete wavelength is at any time apparent.
A Bayesian Analysis of Autoregressive Models with Exogenous Variables and Power-Transformed and Threshold GARCH Errors

Consider a class of autoregressive models with exogenous variables and power transformed and threshold GARCH (ARX-PTTGARCH) errors, which is a natural generalization of the standard and special GARCH model. We propose a Bayesian method to show that combining Gibbs sampler and Metropolis-Hastings algorithm to give a Bayesian analysis can be applied to estimate parameters of ARX-PTTGARCH models with success.
Temporal evolution of the HF-enhanced plasma line in the Arecibo F region

The temporal development of the so-called HF-enhanced plasma line (HFPL) has been studied in detail using the high-power high-frequency (HF) facility located near Arecibo, Puerto Rico. Observations were made with the Arecibo 430-MHz radar. In the current work, attention is focused on the evolution of the HFPL spectrum subsequent to the onset of the HF wave in the F region plasma. The development of the HFPL spectrum is examined for several different HF pulse lengths and HF duty cycles. In this regard, low duty cycles with long HF-off periods tend to consistently produce a different spectral evolution than high duty cycles with short HF-off periods. Broad, diffuse HFPL spectra are observed with low HF duty cycles, whereas sharply defined nonlinear Landau damping cascades develop at high duty cycles. Under a variety of observing conditions, the Arecibo HFPLs are found to develop dominant decay line peaks within a few milliseconds of HF turn-on in the plasma. In addition, at early times during periods of slow HFPL growth, and also for very low HF power levels, weak flat-top and/or double-humped spectral features are observed that can be attributed to radio wave scattering off ion acoustic waves. During periods of strong HFPL excitation, weak spectral signatures are occasionally observed in the band 430 MHz ± (fHF + Δ), where fHF is the HF frequency and Δ = 10–100 kHz. The origin of this structure is currently not known. Finally, the temporal development of the 430-MHz spectra is closely examined during the so-called main plasma line overshoot. A diffuse spectral cascade is evident within a few milliseconds of the onset of the HF wave in the plasma, and dominant decay line peaks quickly develop thereafter. Processes involving direct conversion of the HF wave into Langmuir waves and/or soliton formation do not appear to be the dominant processes responsible for the 430-MHz HFPLs observed in the Arecibo F region. However, the formation of solitons may influence the development of the HFPLs. The measured HFPL spectra are in qualitative agreement with the predictions of nonlinear Landau damping theory, but the experimental observations do not match the theoretical predictions in every detail. It is likely that HF-induced small-scale cavities and/or HF-induced geomagnetic field-aligned irregularities play a central role in determining the amplitude, spectral signature, and temporal development of strongly excited HFPLs at Arecibo.
Distilling Causal Metaknowledge from Knowledge Graphs

In recent years, the explosive increase of information facilitates the massive knowledge graphs, which in turn increase burden of people to understand and leverage the regularity behind these superficial facts. Therefore, the metaknowledge, defined as the knowledge about knowledge, is proposed to identify complex processes of knowledge production and consumption. Unfortunately, even though the current correlation-based rule mining methods in knowledge graph distill the rule-formed metaknowledge, they can not explain the processes of knowledge production. In this paper, we focus on capturing the metaknowledge with causality which is generally regarded as one of the most promising techniques to reveal the interactions between components in the complex system. To the best of our knowledge, this is the first attempt to interpret the knowledge graph from the causal perspective. For this purpose, we propose a causal metaknowledge method for link prediction, which achieves entity-level link prediction by discovering concept-level topological causality. Specifically, we first formalize causal metaknowledge as causal rule, following the form of logical rule. Then, we transform the relational data into propositional data to learn the causal relationships between topological structures. And an efficient algorithm for discovering local causal relationships is proposed using the d -seperation criterion. Eventually, the causal rules generated based on the mined relationships are used for link prediction. Both simulation-based and real data-based experiments demonstrate the effectiveness of the proposed approach, especially under the Out-of-Distribution(OoD) settings.
Optimal extension of the Hausdorff-Young inequality

Abstract Given 1 < p < 2, we construct a Banach function space with σ-order continuous norm which contains and has the property that the Fourier transform map has a continuous ℓ p′ (ℤ)-valued extension to . Moreover, is maximal with these properties and satisfies with both containments proper. Each turns out to be a weakly sequentially complete, translation invariant, homogeneous Banach space and consists precisely of those functions such that for every Borel set . This answers a question of R. E. Edwards posed some 40 years ago.
A study of the infrared characteristics of host IRAS sources with OH megamasers

OH megamasers are the most luminous cosmic maser sources known. So far powerful OH maser emission has been discovered from 90 extragalactic objects. An important observational characteristic of the OH megamaser sources is their relationship between L(OH) and L(IR). We study the relationship between log L(OH) and log L(IR) for the 67 OH megamaser sources for which there are data on L(OH) and L(IR). Accounting for Malmquist bias, the relationship L(OH) ∼L(IR) 1 . 4 1 is obtained. We use the largest sample currently available to study the relationship between L(OH) and L(IR) for OH megamaser sources. Our results agree with Kandalian's results within the uncertainties. The infrared properties of the host IRAS sources with OH megamasers are also studied. The most striking features are the anticorrelation of S(12 μm)/S(25 μm) versus S(60 μm)/ S(100 μm) and the correlation of S(12 μm)/S(25 μm) versus S(25 μm)/S(60 μm). They are consistent with Henkel, Wouterlooy & Bally's finding that S(12 μm)/S(25 μm) is anticorrelated with S(60 μm)/S(100 μm), but are the opposite of Henkel et al.'s result that S(12 μm)/ S(25 μm) is correlated with S(25 μm)/S(60 μm). This is an interesting difference. Our colour-colour plots suggest that the peak of the infrared spectra of our sample of OH sources is at a longer wavelength than the peak in the sample of Henkel et al. This suggests that infrared radiation from our sample is dominated by emission from material at greater separations from the central source.
Consistent symmetric axis method for robust detection of ellipses

Ellipse detection is an interesting issue in machine vision researches and many approaches have been suggested to determine the parameters. Recently, a symmetric axis method has been proposed to determine the centre of an ellipse, but other parameters are determined otherwise. A consistent symmetric axis method is proposed that utilises the information inherent in the symmetric axes throughout the entire process to compute all of the parameters. A closed-form solution is obtained, hence the calculation of the parameters is fast. In addition, since the determination of the symmetric axes involves a set of points on the ellipse, the procedure is robust. Experiments with disjoint ellipses, interacting ellipses, defective ellipses and real objects indicate the effectiveness of the proposed method both theoretically and practically.
‘My Ideal First Day’: Implications for induction from a three (London) university project

This study sets out the initial findings from a mixed methodology approach which aims to research the experiences of first year, first semester students in three UK inner city Universities. Goodenow’s (1993) Psychological Sense of School Membership instrument was utilised to collect quantitative data (n=1300), and Wengraf’s (2001) Biographic Narrative Interpretive Method (BNIM) was employed as a guide to gather the qualitative interview data. Below we report on one strand of the data collected, that of how the students would construct their own ‘ideal first day’.
Direct numerical simulation of turbulent channel flow with permeable walls

The main objectives of this study are to suggest a proper boundary condition at the interface between a permeable block and turbulent channel flow and to investigate the characteristics of turbulent channel flow with permeable walls. The boundary condition suggested is an extended version of that applied to laminar channel flow by Beavers & Joseph (1967) and describes the behaviour of slip velocities in the streamwise and spanwise directions at the interface between the permeable block and turbulent channel flow. With the proposed boundary condition, direct numerical simulations of turbulent channel flow that is bounded by the permeable wall are performed and significant skin-friction reductions at the permeable wall are obtained with modification of overall flow structures. The viscous sublayer thickness is decreased and the near-wall vortical structures are significantly weakened by the permeable wall. The permeable wall also reduces the turbulence intensities, Reynolds shear stress, and pressure and vorticity fluctuations throughout the channel except very near the wall. The increase of some turbulence quantities there is due to the slip-velocity fluctuations at the wall. The boundary condition proposed for the permeable wall is validated by comparing solutions with those obtained from a separate direct numerical simulation using both the Brinkman equation for the interior of a permeable block and the Navier–Stokes equation for the main channel bounded by a permeable block.
Electron and neutron radiation damage effects on a two-phase CCD

Surface and bulk radiation damage effects on a two-phase charge-coupled device (CCD), operated in a multipinned phase (MPP) mode have been evaluated. Two-phase CCD's are one of the candidates for application in the vertex detector of a future linear collider. Flat-band voltage shifts, dark current, dark current spikes, and charge transfer efficiency (CTE) were studied on devices subjected to irradiation with fluences reaching 4.3/spl times/10/sup 12/ electrons/cm/sup 2/ and 8.9/spl times/10/sup 9/ neutrons/cm/sup 2/. An additional source of dark signal in electron irradiated devices was observed and explained by impact ionization by holes, released by tunneling from defect states near the Si-SiO/sub 2/ interface. A model for the CTE in a two-phase CCD as a function of temperature, background charges, and clock timing is described. Calculations based on the model are in good agreement with the experimentally determined values of CTE in electron and neutron irradiated CCD's.
M32: Is there an Ancient and Metal-poor Stellar Population?

Abstract We observed two fields near M32 with the ACS/HRC (Program GO-10572, PI: T. Lauer) on board the Hubble Space Telescope, located at distances of about 1.8' and 5.4' (hereafter F1 and F2, respectively) from the center of M32. To obtain a very detailed and deep color-magnitude diagram (CMD) and to look for short period variability, we obtained time-series imaging of each field in 32-orbit-long exposures using the F435W (B) and F555W (V) filters, spanning a temporal range of 2 days per filter. We focus on our detection of variability on RR Lyrae variable stars, which represents the only way to obtain information about the presence of a very old population (larger than 10 Gyr) in M32 from optical data. Here we present results obtained from the detection of 31 RR Lyrae in these fields: 17 in F1 and 14 in F2. We claim we detected 7+4−3 RR Lyrae variables belonging to M32 in F1 thus indicating the presence of a metal-poor ancient population in M32.
The development of photosensitized pulsed and continuous ultraviolet decontamination techniques for surfaces and solutions

The experimental results of a decontamination process that uses an ultraviolet (UV) light and a chemical photosensitizer for disinfecting surfaces and solutions are reported. Reduction in the microbial viability as a function of applied UV fluence and initial photosensitizer concentration is presented for the inactivation of both the vegetative and spore forms of Bacillus subtilis niger. Encouraging results have been obtained with both aqueous solutions and surfaces; and with both continuous and pulsed UV light sources. Extrapolation of the results and an estimate of the process speed and efficiency permit a comparison with other decontamination methods.
Electromagnetically coupled circular-patch antenna consisting of multilayered configuration

A new multilayered circular-patch antenna fed by an electromagnetic coupling method is proposed. This antenna realizes good impedance matching to a feed line. From experimental results, one observes that the bandwidth is 3.05%, which is 1.4 times wider than that of a conventional circular-patch antenna of the same parameters. The resonant frequency of the proposed circular-patch antenna fed by the proximity method was 1.13 times higher than that of the conventionally fed patch. The bandwidth of the proposed circular-patch antenna fed by the aperture-coupled method was 1.98%, and this bandwidth was 1.2 times wider than that of a conventional circular-patch antenna.
A Hybrid Approximation Bayesian Test of Variance Components for Longitudinal Data

The test of variance components of possibly correlated random effects in generalized linear mixed models (GLMMs) can be used to examine if there exists heterogeneous effects. The Bayesian test with Bayes factors offers a flexible method. In this article, we focus on the performance of Bayesian tests under three reference priors and a conjugate prior: an approximate uniform shrinkage prior, modified approximate Jeffreys' prior, half-normal unit information prior and Wishart prior. To compute Bayes factors, we propose a hybrid approximation approach combining a simulated version of Laplace's method and importance sampling techniques to test the variance components in GLMMs.
Retrieving Aerosols from the Atmospheric Emitted Radiance Interferometer: Can it be Done?

The Atmospheric Emitted Radiance Interferometer observes downwelling infrared radiance from 3-19 μm that may enable better retrievals of aerosol optical and physical properties. Theoretical study suggests that the Atmospheric Emitted Radiance Interferometer’s infrared aerosol signal is strong enough to overcome instrument noise constraints and uncertainties in the water vapor, especially in the 3-4 μm band where scattering dominates the observed signal during the daytime. Unlike other aerosol retrieval methods that generally use wavelengths below 1 μm, the Atmospheric Emitted Radiance Interferometer’s signal is dominated by the contribution from larger aerosols in the size distribution. We have retrieved aerosol optical depth for a range of assumptions of the number of giant particles in the size distribution; these retrievals together with aerosol optical depth retrieved from the multi-filter rotating shadowband radiometer can be used to determine the relative number of giant mode aerosols. Furthermore, different aerosol compositions have unique spectral signatures, which can be exploited in the retrievals.
An Evaluation of James Et Al.'s (1992) Vg Estimation Procedure When Artifacts and True Validity are Correlated

James, Demaree, Muliak, and Ladd (1992) outlined a procedure for estimating the mean (Mp) and variance (Vp) of true validities (p's). This procedure was designed to take into account the potential nonzeo intercorrelations among the three artifacts (predictor reliability, criterion reliability, and range restriction) and p. The accuracy of this new validity generalization procedure was compared with the accuracy of the Model 2-based (in which correlations are individually corrected for artifacts) procedure because this latter procedure does not require the assumption of uncorrelated artifacts. The current study included two different p distributions, three sample sizes, and six different levels of intercorrelations among the three artifacts and p. Both procedures yielded relatively accurate estimates of Mp and Vp even when the intercorrelations among the three artifacts and p were nonzero. The Model 2-based estimates were slightly more accurate than the James et al. estimates, and the accuracy of the Model 2-based estimates was much more stable across sample sizes and different levels of intercorrelatedness. Sample-based artifact data were used in this investigation.
Novel polarization atmosphere Michelson interferometer

Abstract. A novel polarization atmosphere Michelson interferometer (NPAMI) based on PAMI was designed. We explain the method of NPAMI for atmosphere detecting and then analyze the NPAMI by Jones matrix; the equations of retrieval atmospheric wind velocity and temperature are also derived. In contrast to PAMI, the NPAMI decreases the number of times for the polarizer’s rotation and processing data size, thus, highly increasing the speed of detection. This work has great significance on theoretical research, capability improvement, and would be useful for the application on the passive measurement of the wind field of the upper atmosphere.
Design of corrugated waveguide filters by the Gel’fand–Levitan–Marchenko inverse-scattering method

A rigorous design rule of corrugated waveguide filters is developed by employing the Gel’fand–Levitan–Marchenko inverse-scattering method for the two-component coupled-wave equations of the Zakharov–Shabat type. In the course of developing the design method, the coupled Gel’fand–Levitan–Marchenko integral equations for the Zakharov–Shabat system having no discrete spectrum are shown to be reducible to a set of linear simultaneous equations amenable to simple numerical calculations when the reflection coefficient is a rational function.
Inferring Directional Migration Propensities from the Migration Propensities of Infants in the United States

Beginning with the 2010 decennial census, the U.S. Census Bureau plans to drop its long-form questionnaire and to replace it with the American Community Survey (ACS). The resulting absence of the larger sample provided by the census count will complicate the measurement and analysis of internal migration flows. In addition, the strategy of averaging accumulated samples over time will mix changing migration patterns. The migration question will refer to a one-year time interval instead of the five-year interval used in the censuses between 1960 and 2000, complicating historical comparisons and the production of multiregional projections based on five-year age groups. Consequently, students of territorial mobility increasingly will find it necessary to complement or augment possibly inadequate data collected on migration with estimates obtained by means of “indirect estimation. ” A method is presented that allows one to infer age-specific directional migration propensities at the regional level from birthplace-specific infant population data, which approximates infant migration propensities, and from these infers the migration propensities of all other ages. The method is applied to at the nine-division spatial scale.
On the Horizontal Scale of Elevation Dependence of Australian Monthly Precipitation

Abstract Determination of the scale of the interaction between precipitation and topography is important for the accurate interpolation of rainfall in mountainous areas and also provides insight into the physical processes involved. In this paper, trivariate thin-plate smoothing splines are used to investigate the scale of interaction between monthly precipitation and topography by interpolating monthly rainfall over three subregions of the Australian continent, incorporating different climatic conditions and rainfall types. The interpolations are based upon elevations derived from digital elevation models (DEMs) of various resolutions. All of the DEMs are local averages of version 2.0 of the 9-s-resolution DEM of Australia. The results suggest that the optimal scale of the interaction between precipitation and topography, as it pertains to the elevation-dependent interpolation of monthly precipitation in Australia, is between 5 and 10 km. This is in agreement with results of similar studies that addresse.
Social vulnerability shapes the experiences of climate migrants displaced by Hurricane Maria

ABSTRACT Climate change-related shocks and stresses are prompting the movement of hundreds of thousands. The purpose of this study is to understand the experiences of climate change migrants, people displaced from these crises from the initial impacts of the hazard to their recent arrivals in a new location. To do so we draw on focus group discussions with Puerto Ricans in South and Central Florida displaced by 2017 Hurricane Maria. We document the factors leading up to the hurricane that shaped their preparedness, their relocation decisions, and their post-relocation experiences in the initial seven months following the hurricane. We find that for these Puerto Ricans, underlying neglect, discrimination, and other social processes transformed Maria from a hazard to a disaster with devastating economic, social, and physical and mental health effects, while also creating challenges in early recovery. However, migrants were also able to draw on their faith, community and educational institutions, and new neighbours as sources of strength and coping. We argue that since these factors are socially produced, a vulnerability perspective is critical to understanding the experiences of climate migrants. We draw on this perspective to conclude with research and policy implications.