Miracle-dz/UniFAR-FTUs huggingface dataset:
Relativistic dust accretion of charged particles in Kerr-Newman spacetime

We describe a new analytical model for the accretion of particles from a rotating and charged spherical shell of dilute collisionless plasma onto a rotating and charged black hole. By assuming a continuous injection of particles at the spherical shell and by treating the black hole and a featureless accretion disc located in the equatorial plane as passive sinks of particles we build a stationary accretion model. This may then serve as a toy model for plasma feeding an accretion disc around a charged and rotating black hole. Therefore, our new model is a direct generalization of the analytical accretion model introduced by E. Tejeda, P. A. Taylor, and J. C. Miller (2013). We use our generalized model to analyze the influence of a net charge of the black hole, which will in general be very small, on the accretion of plasma. Within the assumptions of our model we demonstrate that already a vanishingly small charge of the black hole may in general still have a non-negligible effect on the motion of the plasma, as long as the electromagnetic field of the plasma is still negligible. Furthermore, we argue that the inner and outer edges of the forming accretion disc strongly depend on the charge of the accreted plasma. The resulting possible configurations of accretion discs are analyzed in detail.
What Would We Learn by Detecting a Gravitational Wave Signal in the Cosmic Microwave Background Anisotropy

Inflation generates gravitational waves, which may be observable in the low multipoles of the cosmic microwave background anisotropy but only if the inflaton field variation is at least of order the Planck scale. Such a large variation would imply that the model of inflation cannot be part of an ordinary extension of the standard model, and combined with the detection of the waves it would also suggest that the inflaton field cannot be one of the superstring moduli. Another implication of observable gravitational waves would be a potential ${V}^{1/4}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2$ to $4\ifmmode\times\else\texttimes\fi{}{10}^{16}\phantom{\rule{0ex}{0ex}}\mathrm{GeV}$, which is orders of magnitude bigger than the prediction of most models.
B1359+154: A Six-Image Lens Produced by a z ≃ 1 Compact Group of Galaxies

Hubble Space Telescope (HST) V- and I-band observations show that the gravitational lens B1359+154 consists of six images of a single zs = 3.235 radio source and its star-forming host galaxy, produced by a compact group of galaxies at zl ≃ 1. Very Long Baseline Array (VLBA) observations at 1.7 GHz strongly support this conclusion, showing six compact cores with similar low-frequency radio spectra. B1359+154 is the first example of galaxy-scale gravitational lensing in which more than four images are observed of the same background source. The configuration is due to the unique lensing mass distribution: three primary lens galaxies lying on the vertices of a triangle separated by 0. ″7 ≃ 4 h-1 kpc, inside the 1. ″7 diameter Einstein ring defined by the radio images. The gravitational potential has additional extrema within this triangle, creating a pair of central images that supplement the "standard" four-image geometry of the outer components. Simple mass models, consisting of three lens galaxies constrained by HST and VLBA astrometry, naturally reproduce the observed image positions but must be finely tuned to fit the flux densities.
A search for transiting planets in the β Pictoris system

Context. Transiting exoplanets provide an opportunity for the characterization of their atmospheres, and finding the brightest star in the sky with a transiting planet enables high signal-to-noise ratio observations. The Kepler satellite has detected over 365 multiple transiting exoplanet systems, a large fraction of which have nearly coplanar orbits. If one planet is seen to transit the star, then it is likely that other planets in the system will transit the star too. The bright (V = 3.86) star β Pictoris is a nearby young star with a debris disk and gas giant exoplanet, β Pictoris b, in a multi-decade orbit around it. Both the planet’s orbit and disk are almost edge-on to our line of sight. Aims. We carry out a search for any transiting planets in the β Pictoris system with orbits of less than 30 days that are coplanar with the planet β Pictoris b. Methods. We search for a planetary transit using data from the BRITE-Constellation nanosatellite BRITE-Heweliusz, analyzing the photometry using the Box-Fitting Least Squares Algorithm (BLS). The sensitivity of the method is verified by injection of artificial planetary transit signals using the Bad-Ass Transit Model cAlculatioN (BATMAN) code. Results. No planet was found in the BRITE-Constellation data set. We rule out planets larger than 0.6 RJ for periods of less than 5 days, larger than 0.75 RJ for periods of less than 10 days, and larger than 1.05 RJ for periods of less than 20 days.
Deterministic model of electric arc furnace – a closed form solution

Purpose – Electric arc furnaces are usually modelled using combined models which divide the phenomenon taking place in real objects into a deterministic and a stochastic or chaotic parts. The former is expressed by a nonlinear differential equation. The goal of this paper was to obtain a closed form of the solution to one of the most popular nonlinear differential equations used for the AC electric arc modelling.Design/methodology/approach – The solution has been obtained in the time domain by a sequence of transformations of the original nonlinear equation which lead to a linear equation, for which a closed form solution is known.Findings – The paper provides a set of parameters for which the solution to the nonlinear differential equation describing electric arc can be obtained in a closed form.Research limitations/implications – There are still some parameter values for which the solution can be found only numerically. Moreover, due to the nature of the phenomena occurring in electric arc furnaces, in .
Modelling of dielectric hysteresis loops in ferroelectric semiconductors with charged defects

We have proposed the phenomenological description of dielectric hysteresis loops in ferroelectric semiconductors with charged defects and prevailing extrinsic conductivity. We have modified the Landau–Ginsburg approach and shown that the macroscopic state of the aforementioned inhomogeneous system can be described by three coupled equations for three order parameters. Both the experimentally observed coercive field values well below the thermodynamic values and the various hysteresis-loop deformations (constricted and double loops) have been obtained in the framework of our model. The obtained results quantitatively explain the ferroelectric switching in such ferroelectric materials as thick PZT films.
Constraints for hypothetical interactions from a recent demonstration of the Casimir force and some possible improvements

The Casimir force is calculated in the configuration of a spherical lens and a disc of finite radius covered by Cu and Au thin layers which was used in a recent experiment. The correction to the Casimir force due to finiteness of the disc radius is shown to be negligible. Also the corrections are discussed due to the finite conductivity, large-scale and short-scale deviations from the perfect shape of the bounding surfaces and the temperature correction. They were found to be essential when confronting the theoretical results with experimental data. Both Yukawa-type and power-law hypothetical forces are computed which may act in the configuration under consideration due to the exchange of light and/or massless elementary particles between the atoms of the lens and the disc. New constraints on the constants of these forces are determined which follow from the fact that they were not observed within the limits of experimental errors. For Yukawa-type forces the new constraints are up to 30 times stronger than the best ones known today. A possible improvement of experimental parameters is proposed which gives the possibility to strengthen constraints on Yukawa-type interactions up to ${10}^{4}$ times and on power-law interactions up to several hundred times.
miR-708-5p Regulates Myoblast Proliferation and Differentiation

Simple Summary Skeletal muscle is a crucial component of an animal’s body. Its growth and development process are modified by a variety of regulatory factors and signaling pathways. It is reported that miR-708-5p is closely related to cancer, osteoporosis, and muscle development. However, the molecular mechanism of miR-708-5p-mediated regulation of myoblast proliferation and differentiation remains unclear. This research aims to investigate the function of miR-708-5p in the proliferation and differentiation of C2C12 myoblasts and analyze its target genes. After interference or overexpression of miR-708-5p, we found that overexpression of miR-708-5p inhibited myoblast proliferation and promoted C2C12 myoblast differentiation. A total of 253 target genes of miR-708-5p were identified. GO and KEGG pathway analysis suggested that these target genes were significantly enriched in terms related to muscle growth and development. Pik3ca, Pik3r3, and Irs1 were identified as the key target genes of miR-708-5p. These results deepen our understanding of the molecular mechanism of skeletal muscle development and provide a theoretical foundation for further exploring the mechanism of miR-708-5p-mediated regulation of skeletal muscle development. Abstract MicroRNAs (miRNAs) are key regulators involved in the myogenic process in skeletal muscles. miR-708-5p plays an important role in various biochemical and physiological processes, but its function in skeletal myogenesis remain unclear. In this study, we first explored the effects of miR-708-5p on C2C12 proliferation and differentiation by overexpression and interference experiments. Then, we predicted the target genes of miR-708-5p and analyzed their function. We found that miR-708-5p was gradually increased during myoblast differentiation. Overexpression of miR-708-5p significantly inhibited cell proliferation and promoted the differentiation of myoblasts. A total of 253 target genes were predicted using a bioinformatics approach. These genes were significantly enriched in muscle growth-related GO terms and KEGG pathways, such as actin filament organization, actin cytoskeleton organization, PI3K-Akt pathway, insulin pathway, and Jak-STAT pathway. Among them, Pik3ca, Pik3r3, and Irs1 were considered to be the key target genes of miR-708-5p. To sum up, miR-708-5p inhibited C2C12 cells proliferation and promoted C2C12 cells differentiation. Its target genes significantly enriched in GO terms and KEGG pathways related to the development and growth of muscle. Our results provided a basis for studies on the function and mechanism of miR-708-5p regulating skeletal muscle growth and development.
Solid-state NMR reveals a comprehensive view of the dynamics of the flexible, disordered N-terminal domain of amyloid- (cid:2) fibrils

Amyloid fibril deposits observed in Alzheimer’s disease com-priseamyloid- (cid:2) (A (cid:2) )proteinpossessingastructuredhydropho-bic core and a disordered N-terminal domain (residues 1–16). The internal flexibility of the disordered domain is likely essen-tial for A (cid:2) aggregation. Here, we used 2 H static solid-state NMR methods to probe the dynamics of selected side chains of the N-terminal domain of A (cid:2) 1–40 fibrils. Line shape and relaxation data suggested a two-state model in which the domain’s free stateundergoesadiffusivemotionthatisquenchedinthebound state,likelybecauseoftransientinteractionswiththestructured C-terminal domain. At 37 °C, we observed freezing of the dynamicsprogressivelyalongtheA (cid:2) sequence,withthefraction of the bound state increasing and the rate of diffusion decreasing. We also found that without solvation, the diffusive motion is quenched. The solvent acted as a plasticizer reminiscent of its role in the onset of global dynamics in globular proteins. As the temperature was lowered, the fraction of the bound state exhib-ited sigmoidal behavior. The midpoint of the freezing curve coincided with the bulk solvent freezing for the N-terminal residues and increased further along the sequence. Using 2 H R 1 (cid:3) measurements, we
Spin and momentum of the light fields in inhomogeneous dispersive media with application to surface plasmon-polariton waves

Following to the recently published approach [Phys. Rev. Lett. 119, 073901 (2017); New J. Phys., 123014 (2017)], we refine and accomplish the general scheme for the unified description of the momentum and angular momentum in complex media. The equations for the canonical (orbital) and spin linear momenta, orbital and spin angular momenta in a lossless inhomogeneous dispersive medium are presented in the compact form analogous to the Brillouin's relation for the energy. The results are applied to the surface plasmon-polariton (SPP) field, and the microscopic calculations support the phenomenological expectations. The refined general scheme correctly describes the unusual SPP properties (transverse spin, magnetization momentum) and additionally predicts the singular momentum contribution sharply localized at the metal-dielectric interface, which is confirmed by the microscopic analysis. The results can be useful in optical systems employing the structured light, especially for microoptics, plasmophotonics, optical sorting and micromanipulation.
Figures of merit for digital multistep pseudorandom numbers

The statistical independence properties of s successive digital multistep pseudorandom numbers are governed by the figure of merit p(s) (I) which depends on s and the characteristic polynomial f of the recursion used in the generation procedure. We extend previous work for s = 2 and describe how to obtain large figures of merit for s > 2, thus arriving at digital multistep pseudorandom numbers with attractive statistical independence properties. Tables of figures of merit for s = 3, 4, 5 and degrees < 32 are included.
Innocent Bystanders: Orbital Dynamics of Exomoons During Planet–Planet Scattering

Planet–planet scattering is the leading mechanism to explain the broad eccentricity distribution of observed giant exoplanets. Here we study the orbital stability of primordial giant planet moons in this scenario. We use N-body simulations including realistic oblateness and evolving spin evolution for the giant planets. We find that the vast majority (∼80%–90% across all our simulations) of orbital parameter space for moons is destabilized. There is a strong radial dependence, as moons past are systematically removed. Closer-in moons on Galilean-moon-like orbits (<0.04 RHill) have a good (∼20%–40%) chance of survival. Destabilized moons may undergo a collision with the star or a planet, be ejected from the system, be captured by another planet, be ejected but still orbiting its free-floating host planet, or survive on heliocentric orbits as “planets. ” The survival rate of moons increases with the host planet mass but is independent of the planet’s final (post-scattering) orbits. Based on our simulations, we predict the existence of an abundant galactic population of free-floating (former) moons.
On the Davies-Unruh effect in a wide range of temperatures

The Debye model of the specific heat of solid at low temperatures is incorporate in the Entropic Gravity Theory (EGT). Rather of a smooth surface, the holographic screen is considered as an oscillating elastic membrane, with a continuous range of frequencies, that cuts off at a maximum (Debye) temperature, $T_D$. We show that at low temperatures $T < T_D$, the conservation of the equivalence principle in EGT requires a modification of the Davies-Unruh effect. While the maintenance of Davies-Unruh effect requires a violation of the equivalence principle. These two possibilities are equivalents, because both can emulate the same quantity of dark matter. However, in both cases, the central mechanism is the Davies-Unruh effect, this seems to indicate that the modification of the Davies-Unruh effect emulates dark matter which in turn can be see as a violation of the equivalence principle. This scenario is promising to explain why MOND theory works at very low temperatures (accelerations) regime, i. e. , the galaxies sector. We also show that in the intermediate region, for temperatures slightly lower or slightly higher than Debye temperature, EGT predicts the mass-temperature relation of hot X-ray galaxy clusters.
Stable interactions in higher derivative field theories of derived type

We consider the general higher derivative field theories of derived type. At free level, the wave operator of derived-type theory is a polynomial of the order $n\geq 2$ of another operator $W$ which is of the lower order. Every symmetry of $W$ gives rise to the series of independent higher order symmetries of the field equations of derived system. In its turn, these symmetries give rise to the series of independent conserved quantities. In particular, the translation invariance of operator $W$ results in the series of conserved tensors of the derived theory. The series involves $n$ independent conserved tensors including canonical energy-momentum. Even if the canonical energy is unbounded, the other conserved tensors in the series can be bounded, that will make the dynamics stable. The general procedure is worked out to switch on the interactions such that the stability persists beyond the free level. The stable interaction vertices are inevitably non-Lagrangian. The stable theory, however, can admit consistent quantization. The general construction is exemplified by the order $N$ extension of Chern-Simons coupled to the Pais-Uhlenbeck-type higher derivative complex scalar field.
Performance of cryogenic microbolometers and calorimeters with on-chip coolers

Astronomical observations of cosmic sources in the far-infrared and x-ray bands require extreme sensitivity. The most sensitive detectors are cryogenic bolometers and calorimeters operating typically at about 100 mK. The last stage of cooling (from 300 to 100 mK) often poses significant difficulties in space-borne experiments, both in system complexity and in reliability. We address the possibility of using refrigeration based on normal metal/insulator/superconductor (NIS) tunnel junctions as the last stage cooler for cryogenic thermal detectors. We compare two possible schemes: direct cooling of the electron gas of the detector with the aid of NIS tunnel junctions and the indirect cooling method, when the detector lattice is cooled by the refrigerating system, while the electron gas temperature is decreased by electron–phonon interaction. The latter method is found to allow at least an order of magnitude improvement in detector noise equivalent power compared to direct electron cooling.
Interaction of conical membrane inclusions: Effect of lateral tension

Considering two rigid conical inclusions embedded in a membrane subject to lateral tension, we study the membrane-mediated interaction between these inclusions that originates from the hat-shaped membrane deformations associated with the cones. At nonvanishing lateral tensions, the interaction is found to depend on the orientation of the cones with respect to the membrane plane. The interaction of inclusions of equal orientation is repulsive at all distances between them, while the inclusions of opposite orientation repel each other at small separations, but attract each other at larger ones. Both the repulsive and attractive forces become stronger with increasing lateral tension. This is different from what has been predicted on the basis of the same static model for the case of vanishing lateral tension. Without tension, the inclusions repel each other at all distances independently of their relative orientation. We conclude that lateral tension may induce the aggregation of conical membrane inclusions.
Isolated, slowly evolving, and dynamical trapping horizons: Geometry and mechanics from surface deformations

We study the geometry and dynamics of both isolated and dynamical trapping horizons by considering the allowed variations of their foliating two-surfaces. This provides a common framework that may be used to consider both their possible evolutions and their deformations as well as derive the well-known flux laws. Using this framework, we unify much of what is already known about these objects as well as derive some new results. In particular we characterize and study the ``almost isolated'' trapping horizons known as slowly evolving horizons. It is for these horizons that a dynamical first law holds and this is analogous and closely related to the Hawking-Hartle formula for event horizons.
Cosmic Microwave Background and Supernova Constraints on Quintessence: Concordance Regions and Target Models

We perform a detailed comparison of the Wilkinson Microwave Anisotropy Probe (WMAP) measurements of the cosmic microwave background (CMB) temperature and polarization anisotropy with the predictions of quintessence cosmological models of dark energy. We consider a wide range of quintessence models, including: a constant equation-of-state; a simply-parametrized, time-evolving equation-of-state; a class of models of early quintessence; scalar fields with an inverse-power law potential. We also provide a joint fit to the CBI and ACBAR CMB data, and the type 1a supernovae. Using these select constraints we identify viable, target models for further analysis.
Directed Ising type dynamic preroughening transition in one dimensional interfaces

We present a realization of directed Ising (DI) type dynamic absorbing state phase transitions in the context of one-dimensional interfaces, such as the relaxation of a step on a vicinal surface. Under the restriction that particle deposition and evaporation can only take place near existing kinks, the interface relaxes into one of three steady states: rough, perfectly ordered flat (OF) without kinks, or disordered flat (DOF) with randomly placed kinks but in perfect up-down alternating order. A DI type dynamic preroughening transition takes place between the OF and DOF phases. At this critical point the asymptotic time evolution is controlled not only by the DI exponents but also by the initial condition. Information about the correlations in the initial state persists and changes the critical exponents.
Stellar rotation at young ages: new results from Corot's monitoring NGC 2264

Stellar rotation at young ages: new results from Corot's Angular momentum is one of the driving forces in the early evolution of stars. Issues such as the coupling between the star and the accretion disk (the so-called disk regulation paradigm), are traced by the evolution of rotational momentum, but affect the star-forming process as a whole. One of the features observed in star-forming regions (e.g. ONC and NGC 2264) of age between 1 and few Myr, for masses above 0.25 solar masses, is a bimodality of the rotational period distribution, with a peak around 1 day and the other at around 4 to 7 days. This bimodality has been interpreted as the smoking gun of the disk-locking mechanism (with the fast rotators having lost their disk and the slow ones still being regulated by their disks).
Broadband slow-wave systems of subwavelength thickness excited by a metal wire

We propose a broadband slow-wave system based on metallic graded gratingstructures of subwavelength thickness. A metal wire is used to excite the slow waves propagating along the gratings. The analysis and full-wave simulations show that the electromagnetic waves could be stopped at designed positions under different frequencies. Experiments are conducted in the microwave frequencies to verify the proposed system. The measured results show very good agreements to the full-wave simulations. We have further modeled a broadband slow-wave system of subwavelength thickness in the terahertz (THz) frequencies to demonstrate its validity.