Miracle-dz/UniFAR-FTUs huggingface dataset:
Correlation of Bragg scattering from the sea surface at different polarizations

The phase interference fading in Bragg backscattering from the sea surface at moderate incidence angles is considered using both moment method calculation of the scattering from measured water profiles and an implementation of the slightly rough, tilted facet model. The fading of the instantaneous scattering cross-section is shown to be independent of the instantaneous phase of the illuminating signal. The vertical and horizontal polarization fading responses are therefore strongly correlated when identical carrier frequencies and modulations are used at both polarizations since the electromagnetic energy is Bragg resonant with the same small-scale roughness in both cases, independent of whether the polarization channels are phase locked. Instantaneous horizontally polarized Bragg backscattering (HH) exceeding that at vertical polarization (VV) is extremely unlikely in this case. Use of an offset in the frequencies of monochromatic signals used at the two polarizations can lead to reduced correlation between the fading if the illumination footprint length is sufficiently large so that the frequency shift introduces a significant additional phase shift between the scattering from the leading and trailing edges of the footprint. The fading shows only a very weak correlation when this phase shift exceeds 400°. HH Bragg backscattering exceeding VV will be much more common under these specialized conditions.
The detection of X-rays from the hot interstellar medium of the Large Magellanic Cloud

A comprehensive reanalysis is presented of the Einstein IPC data base on the LMC, and a number of new algorithms are used to improve the reliability of the point source detection in this crowded region and to produce the first large-scale map of diffuse emission free from the effects of solar scattered X-rays and cosmic-ray particles. Algorithms described in detail include a technique to decontaminate fields containing solar scattered flux, a mechanism for obtaining a spectrum-weighted vignetting function, and a source excision and smoothing algorithm which results in a diffuse map of uniform statistical quality. A catalog of discrete X-rays sources in the direction of the LMC is presented which contains 33 new sources and eliminates a number of spurious and/or marginal directions from previous lists. A possible detection of the long-sought shadowing effect on the cosmic X-ray background produced by cold LMC gas is reported. 61 refs.
Efficient High-Resolution Wake Modeling Using the Vorticity Transport Equation

Computational fluid dynamic models, through their fundamental treatment of the flow physics, present a unique and powerful tool for analyzing the aerodynamics of helicopter rotors. Their effectiveness is often limited though by difficulties in retaining the structure and form of the rotor wake that result from their tendency to dissipate vorticity. The vorticity transport model, developed some years ago, addresses the problem of vorticity diffusion by solving the fundamental fluid dynamic equations in vorticity conservation form. A development of the original model is described that results in a more efficient computational implementation. The new model uses an adaptive grid system to increase grid resolution significantly, with minimal impact on computational cost. The new grid system is effectively boundary free, thus eliminating the need for numerical boundary conditions at the edges of the computational domain. In addition, the new grid system allows very efficient evaluation of the velocity field using a technique based on the Cartesian fast multipole method. The implementation of both the grid system and the velocity calculation is described
A falling film on a porous medium

Abstract A gravity-driven falling film on a saturated porous inclined plane is studied via a continuum approach, where the liquid and porous layers are considered as a single composite layer. Using a weighted residual technique, a two-equation model is derived in terms of the local flow rate $q(x, t)$ and the entire layer thickness $H(x, t)$ . Its linear stability analysis has been satisfactorily compared to the results of the Orr–Sommerfeld problem. The principal effect of the porous substrate on the film flow is to displace the liquid–porous interface to an effective liquid–solid interface located at the lower boundary of the upper momentum boundary layer in the porous medium. The stability and dynamics of the film is thus only weakly affected by the presence of a permeable substrate. In both the linear and the nonlinear regimes, the spatial response of a falling film on a porous medium is not very different from that observed on an impermeable inclined wall. However, the wavy motion of the film triggers a significant exchange of mass at the liquid–porous interface.
On the impacts of the Indian summer monsoon on ENSO in a coupled GCM

This study explores the impacts of the Indian summer monsoon (ISM) on the El Niño–Southern Oscillation (ENSO) evolution by utilizing two coupled general‐circulation model simulations. The first simulation uses the Center for Ocean–Land–Atmosphere Studies anomaly‐coupled model and the second simulation employs a new coupling strategy, interactive ensembles, that is designed to increase the signal‐to‐noise ratio of boundary forcing. The effects of monsoon variability related and unrelated to ENSO are separated through composites in terms of both sea surface temperature (SST) over the Niño‐3.4 area (170°W–120°W,5°S–5°N) and Indian summer monsoon rainfall (IMR) anomalies. It is found that ENSO‐related monsoon variability has significant impacts on warm events. In the interactive‐ensemble simulation, a weak (strong) monsoon enhances (weakens) an ongoing warm event. The monsoon impacts are manifested in the surface zonal wind‐stress anomalies in the western central equatorial Pacific. In the anomaly‐coupled simulation, the monsoon–ENSO relationship is difficult to detect. The ongoing cold events are only weakly affected by monsoon variability. Monsoon variability that is unrelated to ENSO also induces noticeable SST anomalies in the equatorial central Pacific in the following winter. In the interactive‐ensemble model, a weak (strong) monsoon induces noticeable warm (cold) SST anomalies.
THE ARIZONA RADIO OBSERVATORY CO MAPPING SURVEY OF GALACTIC MOLECULAR CLOUDS. IV. THE NGC 1333 CLOUD IN PERSEUS IN CO J = 2–1 AND 13CO J = 2–1

We mapped the NGC 1333 section of the Perseus Molecular Cloud in the J = 2–1 emission lines of 12CO and 13CO over a 50′ × 60′ region (3.4 × 4.1 pc at the cloud distance of 235 pc), using the Arizona Radio Observatory Heinrich Hertz Submillimeter Telescope. The angular resolution is 38″ (0.04 pc) and velocity resolution is 0.3 km s−1. We compare our velocity moment maps with known positions of young stellar objects (YSOs) and (sub)millimeter dust continuum emission. The CO emission is brightest at the center of the cluster of YSOs, but is detected over the full extent of the mapped region at ⩾10 × rms. The morphology of the CO channel maps shows a kinematically complex structure, with many elongated features extending from the YSO cluster outward by ∼1 pc. One notable feature appears as a narrow serpentine structure that curves and doubles back, with a total length of ∼3 pc. The 13CO velocity channel maps show evidence for many low-density cavities surrounded by partial shell-like structures, consistent with previous studies. Maps of the velocity moments show localized effects of bipolar outflows from embedded YSOs, as well as a large-scale velocity gradient around the central core of YSOs, suggestive of large-scale turbulent cloud motions determining the location of current star formation. The CO/13CO intensity ratios show the distribution of the CO opacity, which exhibits a complex kinematic structure. Identified YSOs are located mainly at the positions of greatest CO opacity. The maps are available for download as FITS files.
When action is not least for orbits in general relativity

In Newtonian mechanics, the action for a true trajectory between two spacetime events A and B is a minimum if the final event B occurs before the kinetic focus of the initial event A; otherwise, the action is a saddle point. We give a simplified proof of an analogous theorem in differential geometry for worldlines in a curved spacetime. We locate the kinetic focus for orbits in a Schwarzschild field in the lowest-order post-Newtonian approximation and show that the kinetic focus is shifted beyond its Newtonian value of one angular cycle by a fractional amount of order O(v2/c2).
Stationary Random Processes Associated with Point Processes

1 Preliminaries. - 1 Introduction. - 2 Some notations and conventions. - 3 Ergodic theory - discrete parameter. - 4 Ergodic theory - continuous parameter. - 5 Stationary random elements. - 6 Loynes' lemma. - 7 Queues. - Notes. - 2 Discrete time r.p.@ p.p.- 1 Basic concepts. - 2 Construction of stationary processes. - 3 First and second type relations. - 4 Applications in queueing theory. - Notes. - 3 Continuous time r.p.@ m.p.p.- 1 Random process associated with marked point process. - 2 Construction of stationary r.p.@ m.p.p.'s. - 3 Ergodic theorems. - 4 Relations of the first and second type. - 5 A rate conservative principle approach. - Notes. - 4 Miscellaneous examples. - 1 Inequalities and identities. - 2 Kopoci? ska's model. - 3 Equivalence of distributions of embedded chains in the queue size process. - Notes. - 5 Application to single server queues. - 1 Introductory remarks. - 2 Single server queue with periodic input. - 3 Fagging queueing systems. - 4 $$\overrightarrow G /\overrightarrow G /1$$ queue with work-conserving normal discipline. - 5 Takacs relation in G/G/1 FIFO. queues. - 6 Takacs relation in GI/GI/1 FIFO queues. - Notes. - References.
Learning to Collocate Neural Modules for Image Captioning

We do not speak word by word from scratch; our brain quickly structures a pattern like \textsc{sth do sth at someplace} and then fill in the detailed description. To render existing encoder-decoder image captioners such human-like reasoning, we propose a novel framework: learning to Collocate Neural Modules (CNM), to generate the ``inner pattern'' connecting visual encoder and language decoder. Unlike the widely-used neural module networks in visual Q\&A, where the language (\ie, question) is fully observable, CNM for captioning is more challenging as the language is being generated and thus is partially observable. To this end, we make the following technical contributions for CNM training: 1) compact module design --- one for function words and three for visual content words (\eg, noun, adjective, and verb), 2) soft module fusion and multi-step module execution, robustifying the visual reasoning in partial observation, 3) a linguistic loss for module controller being faithful to part-of-speech collocations (\eg, adjective is before noun). Extensive experiments on the challenging MS-COCO image captioning benchmark validate the effectiveness of our CNM image captioner. In particular, CNM achieves a new state-of-the-art 127.9 CIDEr-D on Karpathy split and a single-model 126.0 c40 on the official server. CNM is also robust to few training samples, \eg, by training only one sentence per image, CNM can halve the performance loss compared to a strong baseline.
The 2001 US Naval Observatory Double Star CD-ROM. III. The Third Catalog of Interferometric Measurements of Binary Stars

The Third Catalog of Interferometric Measurements of Binary Stars includes all published measures of binary and multiple star systems obtained by high-resolution techniques (speckle interferometry, photoelectric occultation timings, etc.), as well as negative examinations for duplicity, as of 2001 January 1. This catalog is one of four USNO double star catalogs to be included on a new CD-ROM. A brief summary and statistical analysis of the contents of the catalog are presented.
Steady flow and evaporation of a volatile liquid in a wedge

We develop a lubrication-type model of a liquid flow in a wedge in the limit of small capillary numbers and negligible gravity. Liquid flows under the action of capillary pressure gradients and thermocapillary stresses, and evaporates due to heating from the solid walls on which a constant axial temperature gradient is imposed. Steady vapor-liquid interface shapes are found for different wedge angles and material properties of the liquid. In the limit of weak evaporation (e.g., in the adiabatic region of a heat pipe) and negligible Marangoni number, the flow rate is the same in all cross sections and can be controlled by changing the wedge angle. We find the wedge angle that results in the maximum value of the flow rate for a given contact angle. For finite evaporation rates, both the flow rate and the amount of liquid in each cross section along the wedge decrease until the point of dry-out is reached. The location of the dry-out point is studied as a function of evaporation conditions. Somewhat counterintuitively, we find that the dry-out point shifts toward the region of higher temperature as evaporation intensity is increased. The effect of thermocapillary stresses on the vapor-liquid interface shape is also investigated in the limit of negligible evaporation. Since thermocapillarity generally opposes the capillary flow, it leads to shorter wetted lengths. The implications of the results for design and optimization of micro heat pipes are discussed.
Quantum mechanical scattering calculations for charge exchange: O + H+ ↔ O+ + H

Thermal energy collisions of oxygen atoms with protons ( O+H + ) may lead to fine-structure excitation of the oxygen or to charge exchange (O + +H ). The reverse process, collisions of oxygen ions with hydrogen, may also lead to charge exchange. Detailed quantum mechanical calculations of these processes are presented here. The potential curves and coupling terms of 3 � − symmetry used are those recently calculated by Spirko et al (2000 J. Phys. B: At. Mol. Opt. Phys. 33 2395–407). The other necessary potentials, the A 3 � and 5 � curves, were taken from the literature. Cross sections for charge exchange and fine-structure excitation are reported. For several transitions, mechanisms based on curve crossings are proposed. The analysis indicates that the scattering cross sections are sensitive to the form of the molecular potentials for internuclear distances of 10–15 a0 . T he only point of comparison with experiment is for rate constants for charge exchange, averaged over fine-structure levels. The present results, as well as other recent calculations, lie within the large error bars of the limited experimental data.
Robust stability of uncertain time-delay systems

This paper presents several sufficient conditions, delay-independent or delay-dependent, that guarantee the robust stability of uncertain time-delay systems subjected to parametric perturbations. Both single and composite uncertain systems with one delayed state are considered and each of these results, expressed by a succinct scalar inequality, permits the assessment of the transient behaviour of uncertain systems. The robustness of the time-delay system with respect to delay uncertainty is also discussed. Furthermore, these results are extended to the perturbed systems with multiple non-commensurate time delays. It is shown that the parameter perturbations may destabilize the system; hence the nominal system should be sufficiently stable to ensure robust stability.
Metrically Un-knotted Corank 1 Singularities of Surfaces in R 4

The paper is devoted to relations between topological and metric properties of germs of real surfaces, obtained by analytic maps from R 2 to R 4 . We show that for a big class of such surfaces, the normal embedding property implies the triviality of the knot, presenting the link of the surfaces. We also present some criteria of normal embedding in terms of the polar curves.
Holomorphic Equivalence and Nonlinear Symmetries of Ruled Hypersurfaces in C 2

We solve the local equivalence problem for ruled hypersurfaces in C 2 at a point of inﬁnite type by giving a normal form. We describe all ruled hypersurfaces which admit nonlinear symmetries and give their complete characterization according to the dimension of their automorphism group. As an application, we give a bound for the dimension of the stability group for a family of nonminimal hypersurfaces.
Global W 1 , p estimates for solutions to the linearized Monge–Ampère equations

In this paper, we investigate regularity for solutions to the linearized Monge–Ampère equations when the nonhomogeneous term has low integrability. We establish global W 1 , p estimates for all p < nqn − q for solutions to the equations with right-hand side in L q where n / 2 < q ≤ n . These estimates hold under natural assumptions on the domain, Monge–Ampère measures, and boundary data. Our estimates are afﬁne invariant analogues of the global W 1 , p estimates of N . Winter for fully nonlinear, uniformly elliptic equations.
Computing the Waiting Time Distribution for the G/G/1 Queue by Signal Processing Methods

Two methods, based on signal processing techniques, are presented for obtaining numerical solutions for the general single server queue with first-come, first-served discipline. The first method is based on the use of the fast Fourier transform (FFT) for producing iterative solutions to a discrete version of Lindley's integral equation for both nonsteady state and equilibrium conditions. The second method makes use of the complex cepstrum, implemented with the FFT, for providing direct solutions with the queue in equilibrium.
Periodic Enhanced Frame Based Long-Short-Term Reference in HEVC for Conference and Surveillance Video Coding

The coding tools of the High Efficiency Video Coding (HEVC) standard were essentially designed for ordinary video contents. They have not fully exploited the long-term temporal dependence of surveillance videos and conference videos, in which the backgrounds are generally stationary. In this paper, a periodic-enhanced frame-based long-short-term reference scheme is presented for coding the videos with stationary backgrounds. First, periodic-enhanced frames are proposed based on global rate-distortion optimization, in which the background error propagation characteristic is introduced to reduce the long-term temporal redundancy. Second, two limitations, such as temporary occlusion and quantization error, are analyzed as applying the enhanced frame on a default HEVC hierarchical prediction structure. In order to reduce the limitations, a long-short-term reference scheme is presented based on the enhanced frames. In this scheme, the periodic-enhanced frames are employed as a long-term reference picture, and the adjacent frames are set as short-term reference pictures. The proposed method is verified by testing on the conference videos and surveillance videos.
Oligomeric Architecture of Mouse Activating Nkrp1 Receptors on Living Cells

Mouse activating Nkrp1 proteins are commonly described as type II transmembrane receptors with disulfide-linked homodimeric structure. Their function and the manner in which Nkrp1 proteins of mouse strain (C57BL/6) oligomerize are still poorly understood. To assess the oligomerization state of Nkrp1 proteins, mouse activating EGFP-Nkrp1s were expressed in mammalian lymphoid cells and their oligomerization evaluated by Förster resonance energy transfer (FRET). Alternatively, Nkrp1s oligomers were detected by Western blotting to specify the ratio between monomeric and dimeric forms. We also performed structural characterization of recombinant ectodomains of activating Nkrp1 receptors. Nkrp1 isoforms c1, c2 and f were expressed prevalently as homodimers, whereas the Nkrp1a displays larger proportion of monomers on the cell surface. Cysteine-to-serine mutants revealed the importance of all stalk cysteines for protein dimerization in living cells with a major influence of cysteine at position 74 in two Nkrp1 protein isoforms. Our results represent a new insight into the oligomerization of Nkrp1 receptors on lymphoid cells, which will help to determine their function.
UGC 4211: A Confirmed Dual Active Galactic Nucleus in the Local Universe at 230 pc Nuclear Separation

We present multiwavelength high-spatial resolution (∼0.″1, 70 pc) observations of UGC 4211 at z = 0.03474, a late-stage major galaxy merger at the closest nuclear separation yet found in near-IR imaging (0.″32, ∼230 pc projected separation). Using Hubble Space Telescope/Space Telescope Imaging Spectrograph, Very Large Telescope/MUSE+AO, Keck/OSIRIS+AO spectroscopy, and the Atacama Large Millimeter/submillimeter Array (ALMA) observations, we show that the spatial distribution, optical and near-infrared emission lines, and millimeter continuum emission are all consistent with both nuclei being powered by accreting supermassive black holes (SMBHs). Our data, combined with common black hole mass prescriptions, suggest that both SMBHs have similar masses, logMBH/M⊙ ∼ 8.1 (south) and logMBH/M⊙ ∼ 8.3 (north), respectively. The projected separation of 230 pc (∼6× the black hole sphere of influence) represents the closest-separation dual active galactic nuclei (AGN) studied to date with multiwavelength resolved spectroscopy and shows the potential of nuclear (<50 pc) continuum observations with ALMA to discover hidden growing SMBH pairs. While the exact occurrence rate of close-separation dual AGN is not yet known, it may be surprisingly high, given that UGC 4211 was found within a small, volume-limited sample of nearby hard X-ray detected AGN. Observations of dual SMBH binaries in the subkiloparsec regime at the final stages of dynamical friction provide important constraints for future gravitational wave observatories.
Singular spectrum analysis of storm surges and wave climates

The Singular Spectrum Analysis (SSA) was used to investigate different time scales within recordings of interest in coastal flooding research. The analysis was in particular applied to sea-level and wind wave measurements. Short time series of sea-level data collected during storm surge events by gauges located on offshore platforms in the Adriatic Sea were considered to demonstrate the actual efficiency of SSA in separating different components of recorded sea-level oscillation, and in detecting its main modal frequencies. This analysis also allowed for an investigation on energy decay of seiches, due, in particular, to the excitation of the first gravitational normal mode of the Adriatic Sea.Wind waves measurements were further used to test a simple procedure to apply SSA to records in presence of gaps. The procedure is shown to be effective, and it does not significantly affect the detection of the underlying annual cycle present in the data.