Miracle-dz/UniFAR-FTUs huggingface dataset:
Observation of aerodynamic instability in the flow of a particle stream in a dilute gas

Forming macroscopic solid bodies in circumstellar discs requires local dust concentration levels significantly higher than the mean. Interactions of the dust particles with the gas must serve to augment local particle densities, and facilitate growth past barriers in the metre size range. Amongst a number of mechanisms that can amplify the local density of solids, aerodynamic streaming instability (SI) is one of the most promising. This work tests the physical assumptions of models that lead to SI in protoplanetary discs (PPDs). We conduct laboratory experiments in which we track the three-dimensional motion of spherical solid particles fluidised in a low-pressure, laminar, incompressible, gas stream. The particle sizes span the Stokes–Epstein drag regime transition and the overall dust-to-gas mass density ratio,ϵ, is close to unity. A recently published study establishes the similarity of the laboratory flow to a simplified PPD model flow. We study velocity statistics and perform time-series analysis of the advected flow to obtain experimental results suggesting an instability due to particle-gas interaction: (i) there exist variations in particle concentration in the direction of the mean relative motion between the gas and the particles, that is the direction of the mean drag forces; (ii) the particles have a tendency to “catch up” to one another when they are in proximity; (iii) particle clumping occurs on very small scales, which implies local enhancements above the backgroundϵby factors of several tens; (iv) the presence of these density enhancements occurs for a meanϵapproaching or greater than 1; (v) we find evidence for collective particle drag reduction when the local particle number density becomes high and when the background gas pressure is high so that the drag is in the continuum regime. The experiments presented here are precedent-setting for observing SI under controlled conditions and may lead to a deeper understanding of how it operates in nature.
A new non-convex model of the binary asteroid 90 Antiope obtained with the SAGE modelling technique

We present a new non-convex model of the 90 Antiope binary asteroid, derived with a modified version of the SAGE (Shaping Asteroids with Genetic Evolution) method using disk-integrated photometry only. A new variant of the SAGE algorithm capable of deriving models of binary systems is described. The model of 90 Antiope confirms the system's pole solution ($\lambda=199^{\circ}$, $\beta=38^{\circ}$, $\sigma=\pm5^{\circ}$) and the orbital period ($16.505046 \pm 0.000005$ h). A comparison between the stellar occultation chords obtained during the 2011 occultation and the projected shape solution has been used to scale the model. The resulting scaled model allowed us to obtain the equivalent radii ($R_{1}=40.4\pm0.9$ km and $R_{2}=40.2\pm0.9$ km) and the distance between the two system components ($176\pm4$ km), leading to a total system mass of ($9.14\pm0.62$)$\cdot10^{17}$ kg. The non-convex shape description of the components permitted a refined calculation of the components' volumes, leading to a density estimation of $1.67\pm0.23$ g cm$^{-3}$. The intermediate-scale features of the model may also offer new clues on the components' origin and evolution.
Ultraviolet-Optical Observations of the Seyfert 2 Galaxies NGC 7130, NGC 5135, and IC 3639: Implications for the Starburst-Active Galactic Nucleus Connection

We present and discuss Hubble Space Telescope (HST) (WFPC2 and FOC) images and ultraviolet (GHRS) spectra plus ground-based optical spectra of three Seyfert 2 nuclei (NGC 7130, NGC 5135 and IC 3639). These galaxies, together with Mrk 477 (Heckman et al.), were selected on the basis of ultraviolet brightness from a bigger sample that comprises the 20 brightest Seyfert 2 nuclei, with the goal of studying the starburst-active galactic nucleus (AGN) connection and the origin of the so-called "featureless continuum" in Seyfert 2 nuclei. The data provide direct evidence of the existence of nuclear starbursts that dominate the ultraviolet light and that are responsible for the featureless continuum in these type 2 Seyfert nuclei. The GHRS spectra show absorption features formed in the photospheres (S V λ1501, C III λλ1426, 1428, Si III λ1417, and Si III + P III λ1341-1344) and in the stellar winds (C IV λ1550, Si IV λ1400, and N V λ1240) of massive stars. Signatures of massive stars are also clearly detected in their optical and near-UV spectra where the high-order Balmer series and He I lines are observed in absorption. These lines are formed in the photospheres of O and B stars, and thus they also provide strong independent evidence of the presence of massive stars in the nuclei of these Seyfert 2 nuclei. Interstellar absorption lines similar to those formed in the interstellar medium of starbursts are also observed. They are blueshifted by a few hundred km s-1 with respect to the systemic velocity, indicating that the interstellar gas is outflowing. These outflows are most likely driven by the nuclear starburst. These starbursts are dusty, compact, and powerful. They have sizes ranging from less than 100 pc to a few hundred parsecs (much smaller than that seen in the prototype Seyfert 2 galaxy NGC 1068). Their UV colors imply that they are heavily reddened (by 2 to 3 mag in the UV), and the implied bolometric luminosities are of order 1010 L☉. The bolometric luminosities of these starbursts are similar to the estimated bolometric luminosities of their obscured Seyfert 1 nuclei. The data on this small sample suggest that more powerful AGNs may be related to more powerful central starbursts. Comparing the HST spectra to IUE spectra obtained through apertures with projected sizes of 3-11 kpc (and to IRAS far-IR data) we estimate that the nuclear starbursts account for 6%-25% of the total intrinsic UV luminosity of the entire galaxy.
Evaluation of the traditional dimensions of residential segregation by educational level in Chile

RESUMEN La segregación residencial es parte del camino causal de diferentes resultados de salud y se estudia principalmente ligada a la raza. En 1988, Massey y Denton propusieron 5 dimensiones teóricas de la segregación residencial: desigualdad, exposición, agrupamiento, concentración y centralización, que confirmaron utilizando índices de las proporciones de razas de EEUU. Estos índices son ampliamente utilizados, sin embargo, en Chile la segregación es determinada por niveles socioeconómicos y educacionales. Este estudio pretende evaluar si las dimensiones tradicionales de la segregación residencial se mantienen cuando se utilizan variables de segregación y poblaciones diferentes, tales como el nivel educacional en Chile. Replicamos la evaluación de Massey y Denton construyendo 20 índices de segregación educacional en 247 comunas chilenas. Construimos la matriz de correlaciones de los índices y realizamos un análisis factorial de ejes principales y comparamos nuestros resultados con los de esos autores. No hay una alta intercorrelación entre los índices asociados con las 5 dimensiones teóricas excepto por la dimensión de desigualdad y parcialmente, exposición. Esto se reafirma por el análisis factorial exploratorio, en que no es posible verificar de manera empírica las mismas dimensiones. Este estudio demuestra la necesidad de caracterizar localmente no solo los índices de segregación residencial, sino también las dimensiones teóricas a las que se refieren con el propósito de mejorar las interpretaciones de los efectos de la segregación residencial sobre la salud.
Many-body Anderson localization in one-dimensional systems

We show, using quasi-exact numerical simulations, that Anderson localization in a disordered one-dimensional potential survives in the presence of attractive interaction between particles. The localization length of the particles' center of mass—computed analytically for weak disorder—is in good agreement with the quasi-exact numerical observations using the time evolving block decimation algorithm. Our approach allows for simulation of the entire experiment including the final measurement of all atom positions.
Graphene under the influence of Aharonov-Bohm flux and constant magnetic field

Investigation of real two-dimensional systems with Dirac-like electronic behavior under the influence of magnetic field is challenging and leads to many interesting physical results. In this paper we study 2D graphene model with a particular form of magnetic field as a superposition of a homogeneous field and an Aharonov-Bohm vortex. For this configuration, electronic wave functions and energy spectrum were obtained and it was shown that the magnetic Aharonov-Bohm vortex plays the role of a charge impurity. As a demonstration of vacuum properties of the system, vacuum current, as well as an electric current, is calculated and their representation for particular limiting cases of magnetic field is obtained.
Starch and Cellulose Degradation in the Rumen and Applications of Metagenomics on Ruminal Microorganisms

Simple Summary Starch and cellulose are the principal components in diets for dairy cows worldwide, providing the primary energy to the rumen microorganisms as well as the host. Starch and cellulose degradation in the rumen have always been of key importance for dairy cows to obtain high production performance. To improve the starch- and cellulose-degrading activities in the rumen, the amylolytic and cellulolytic microbes and the related enzymes need to be well understood. As the rapid development of sequencing technologies, bioinformatic tools and reference databases, the rumen metagenomics have made great progress in mining the rumen microbial community for novel enzymes, such as the carbohydrate active enzymes (CAZymes). This review will summarize the ruminal microbes and enzymes involved in starch and cellulose degradation. Recent studies with metagenomics techniques on CAZymes related to starch and cellulose degradation will be discussed. Abstract Carbohydrates (e.g., starch and cellulose) are the main energy source in the diets of dairy cows. The ruminal digestion of starch and cellulose is achieved by microorganisms and digestive enzymes. In order to improve their digestibility, the microbes and enzymes involved in starch and cellulose degradation should be identified and their role(s) and activity known. As existing and new analytical techniques are continuously being developed, our knowledge of the amylolytic and cellulolytic microbial community in the rumen of dairy cows has been evolving rapidly. Using traditional culture-based methods, the main amylolytic and cellulolytic bacteria, fungi and protozoa in the rumen of dairy cows have been isolated. These culturable microbes have been found to only account for a small fraction of the total population of microorganisms present in the rumen. A more recent application of the culture-independent approach of metagenomics has acquired a more complete genetic structure and functional composition of the rumen microbial community. Metagenomics can be divided into functional metagenomics and sequencing-based computational metagenomics. Both approaches have been applied in determining the microbial composition and function in the rumen. With these approaches, novel microbial species as well as enzymes, especially glycosyl hydrolases, have been discovered. This review summarizes the current state of knowledge regarding the major amylolytic and cellulolytic microorganisms present in the rumen of dairy cows. The ruminal amylases and cellulases are briefly discussed. The application of metagenomics technology in investigating glycosyl hydrolases is provided and the novel enzymes are compared in terms of glycosyl hydrolase families related to amylolytic and cellulolytic activities.
Plasmon-polaritons on the surface of a pseudosphere

Plasmon-polariton behavior on the surfaces of constant negative curvature is considered. Analytical solutions for the eigenfrequencies and eigenfunctions are found, which describe resonant behavior of metal nanotips and nanoholes. These resonances may be used to improve performance of metal tips and nanoapertures in various scanning probe microscopy and surface-enhanced spectroscopy techniques.
Electron Correlation and Pairing States in Superconductors without Inversion Symmetry

This article is a pedagogical review of theoretical studies of noncentrosymmetric superconductors with particular emphasis on the role played by electron correlation, which is important for heavy fermion systems. We survey unique properties of parity-violated superconductivity such as the admixture of spin singlet and triplet states, unusual paramagnetism, large Pauli limiting fields, magnetoelectric effects, the helical vortex phase, and the anomalous Hall effect. It is pointed out that these remarkable features are strengthened by a strong electron correlation effect, and thus are prominent in heavy fermion superconductors without inversion symmetry. We also discuss possible pairing states realized in the heavy fermion system CePt3Si.
From statistics of regular tree-like graphs to distribution function and gyration radius of branched polymers

We consider flexible branched polymer, with quenched branch structure, and show that its conformational entropy as a function of its gyration radius R, at large R, obeys, in the scaling sense, Δ S ∼ R 2 / ( a 2 L ) ? > , with a bond length (or Kuhn segment) and L defined as an average spanning distance. We show that this estimate is valid up to at most the logarithmic correction for any tree. We do so by explicitly computing the largest eigenvalues of Kramers matrices for both regular and ‘sparse’ three-branched trees, uncovering on the way their peculiar mathematical properties.
Two-dimensional hyperferroelectric metals: A different route to ferromagnetic-ferroelectric multiferroics

Recently, two-dimensional (2D) multiferroics have attracted a lot of attention due to their fascinating properties and promising applications. Although the ferroelectric (FE)-ferroelastic and ferromagnetic (FM)-ferroelastic multiferroics have been observed/predicted in 2D systems, 2D ferromagnetic-ferroelectric (FM-FE) multiferroics remain to be discovered since FM insulators are very rare. Here we proposed the concept of 2D hyperferroelectric metals, with which the insulating prerequisite for the FM-FE multiferroic is no longer required in 2D systems. We validate the concept of 2D hyperferroelectric metals and 2D metallic FM-FE multiferroics by performing first-principle calculations on 2D CrN and $\mathrm{Cr}{\mathrm{B}}_{2}$ systems. The 2D buckled monolayer CrN is found to be a hyperferroelectic metal with the FM ground state, i.e., a 2D FM-FE multiferroic. With the global optimization approach, we find the 2D $\mathrm{Cr}{\mathrm{B}}_{2}$ system has an antiferromagnetic (AFM)/planar ground state and a FM/FE metastable state, suggesting that it can be used to realize electric field control of magnetism. Our analysis demonstrates that the spin-phonon coupling and metal-metal interaction are two mechanisms for stabilizing the out-of-plane electric polarization in 2D systems. Our work not only extends the concept of FE to metallic systems, but also paves a way to search the long-sought high temperature FM-FE multiferroics.
Electrical observation of a tunable band gap in bilayer graphene nanoribbons at room temperature

We investigate the transport properties of double-gated bilayer graphene nanoribbons at room temperature. The devices were fabricated using complementary metal-oxide semiconductor (CMOS)-compatible processes. By analyzing the dependence of the resistance at the charge neutrality point as a function of the electric field applied perpendicular to the graphene surface, we show that a band gap in the density of states opens, reaching an effective value of ∼50 meV. This demonstrates the potential of bilayer graphene as channel material for a field-effect transistor in a conventional CMOS environment.
Chemically peculiar stars as seen with 2MASS

The chemically peculiar (CP) stars of the upper main sequence are well suited for investigating the impact of magnetic fields and diffusion on the surface layers of slowly rotating stars. They can even be traced in the Magellanic Clouds and are important to the understanding of the stellar formation and evolution. A systematic investigation of the near-infrared (NIR), 2MASS JHKs, photometry for the group of CP stars has never been performed. Nowadays, there is a great deal of data available in the NIR that reach very large distances. It is therefore very important for CP stars to be unambiguously detected in the NIR region and for these detections to be used to derive astrophysical parameters (age and mass) by applying isochrone fitting. Furthermore, we investigated whether the CP stars behave in a different way to normal-type stars in the various photometric diagrams. For our analysis, we carefully compiled a sample of CP and apparently normal (non-peculiar) type stars. Only stars for which high-quality (i.e. with low error levels), astrometric, and photometric data are available were chosen. In total, 639 normal and 622 CP stars were selected and further analysed. All stars were dereddened and calibrated in terms of the effective temperature and absolute magnitude (luminosity). Finally, isochrone fitting was applied. No differences in the astrophysical parameters derived from 2MASS and Johnson UBV photometry were found. Furthermore, no statistical significant deviations from the normal type stars within several colour-colour and colour-magnitude diagrams were discovered. Therefore, it is not possible to detect new CP stars with the help of the photometric 2MASS colours only. A new effective temperature calibration, valid for all CP stars, using the (V-Ks)0 colour was derived.
Technology Innovation Continues to Drive Aerospace Electronic Systems Development

The IEEE Aerospace & Electronics Systems Society (AESS) is turning 50 years old in January 2023. The Society emerged in 1973 from several Institute of Radar Engineers groups during a period of significant research in space systems, avionics, and integrated electronics. The history of these technology innovations is significant in AESS's early influences on system designs and its continued importance on the evolution of system and digital signal processing. Because of continued industry development of space and airborne architectures and highly integrated electronics, the applications are available for worldwide commercial systems development.
3d supersymmetric gauge theories and Hilbert
 series

The Hilbert series is a generating function that enumerates gauge invariant chiral operators of a supersymmetric field theory with four supercharges and an R-symmetry. In this article I review how counting dressed 't Hooft monopole operators leads to a formula for the Hilbert series of a 3d $\mathcal{N}\geq 2$ gauge theory, which captures precious information about the chiral ring and the moduli space of supersymmetric vacua of the theory.
A LEPTONIC MODEL OF STEADY HIGH-ENERGY GAMMA-RAY EMISSION FROM Sgr A*

Recent observations of Sgr A* by Fermi and HESS have detected steady γ-ray emission in the GeV and TeV bands. We present a new model to explain the GeV γ-ray emission by inverse Compton scattering by nonthermal electrons supplied by the NIR/X-ray flares of Sgr A*. The escaping electrons from the flare regions accumulate in a region with a size of ∼1018 cm and magnetic fields of ≲ 10−4 G. Those electrons produce γ-rays by inverse Compton scattering off soft photons emitted by stars and dust around the central black hole. By fitting the GeV spectrum, we find constraints on the magnetic field and the energy density of optical-UV radiation in the central 1 pc region around the supermassive black hole. While the GeV spectrum is well fitted by our model, the TeV γ-rays, whose spectral index is different from that of the GeV emission, may be from different sources such as pulsar wind nebulae.
Dynamic Skill Learning From Human Demonstration Based on the Human Arm Stiffness Estimation Model and Riemannian DMP

Traditional skill transfer frameworks mainly focus on kinematics, while there has been a lack of studies on dynamics. This article develops a Riemannian-based dynamic movement primitive (DMP) framework for learning and generalizing multispace data, including position, orientation, and stiffness from human demonstration. A simplified geometric configuration of the human arm skeleton is adopted to extract its endpoint stiffness. The dynamic skills of a variable stiffness are obtained in real time and then transferred to robots. The effectiveness of the presented approach is verified by two experiments in real scenarios on the Franka Emika Panda robot. The experimental results indicate that both kinematic and dynamic skills can be learned and generalized by the extended DMP framework with high accuracy and strong correlation. The human-like variable impedance control of a robot can be successfully realized by using the proposed approach. Thus, the proposed approach, including the stiffness estimation model and the skill learning and generalization framework, is suitable for applications of human–robot collaboration, contact operation, and teleoperation, where the position, orientation, and stiffness need to be considered simultaneously.
Phase Transitions in Liquid Crystals With Disk-Like and Graphene Molecules

The research of possible types of phase diagrams in liquid crystals with discotic mesogens and “graphene molecules” was carried out within the framework of the Landau theory of phase transitions. The possible types of ordering of mesogens in such systems are considered. Keywords—liquid crystals, discotic, nematics, mesophases
Progress and Perspectives in the Management of Wound Infections

The progress in nanotechnology and the medical application of novel generations of nanomaterials have opened new horizons in the definition of non-conventional approaches against multiple diseases. Biomaterials coated with antimicrobial metal nanoparticles, along with the topical applications of zinc, silver or copper-based formulations have demonstrated huge potential in prevention from infections associated with implantable medical devices and in biofilm eradication. In wound healing, in particular, the increasing healthcare costs and the antibiotic resistance demonstrated by several microorganisms have encouraged researchers and companies in the development of innovative wound dressings with antibacterial properties and capability to promote and enhance the healing process. Supported by scientific evidence, many formulations have been proposed and a large number of works involves the use of hybrid metal nanoparticles/polymer products, which have demonstrated encouraging results both in vitro and in vivo. In this chapter, recent progress in the development of novel wound dressings based on antibacterial metal nanoparticles is presented, along with the most interesting results achieved by the authors, mainly devoted to the application of silver nanocoatings in wound management.