Miracle-dz/UniFAR-FTUs huggingface dataset:
Generalized hydrodynamics of active polar suspensions

We utilize a generalized Irving-Kirkwood procedure to derive the hydrodynamic equations of an active matter suspension with internal structure and driven by internal torque. The internal structure and torque of the active Brownian particles give rise to a balance law for internal angular momentum density, making the hydrodynamic description a polar theory of continuum mechanics. We derive exact microscopic expressions for the stress tensor, couple stress tensor, internal energy density, and heat flux vector. Unlike passive matter, the symmetry of the stress tensor is broken explicitly due to active internal torque and the antisymmetric component drives the internal angular momentum density. These results provide a molecular basis to understand the transport characteristics and collectively provide a strategy to develop the theory of linear irreversible thermodynamics of active matter.
Dependence of convective boundary mixing on boundary properties and turbulence strength

EU-FP7-ERC-2012-St Grant [306901]; World Premier International Research Centre Initiative (WPI Initiative), MEXT, Japan; COST (European Cooperation in Science and Technology) [CA16117]; NASA [NNX17AG24G]; Office of Science of the U.S. Department of Energy [DE-AC02-05CH11231]; National Science Foundation [OCI-1053575]; NSF at the University of Arizona [1107445]; BIS National E-infrastructure capital grant [ST/K00042X/1]; STFC capital grants [ST/H008519/1, ST/K00087X/1]; STFCDiRAC Operations grant [ST/K003267/1]; Durham University; PRACE; Barcelona Supercomputing Center, Spain
An HLLC Riemann solver for relativistic flows ¿ I. Hydrodynamics

We present an extension of the HLLC approximate Riemann solver by Toro, Spruce and Speares to the relativistic equations of fluid dynamics. The solver retains the simplicity of the original two-wave formulation proposed by Harten, Lax and van Leer (HLL) but it restores the missing contact wave in the solution of the Riemann problem. The resulting numerical scheme is computationally efficient, robust and positively conservative. The performance of the new solver is evaluated through numerical testing in one and two dimensions.
Is cosmic expansion of the universe accelerating

Currently available Type Ia distant supernovae observed data seem to support evidence that the cosmic expansion of the universe is accelerating. This unexpected result is beyond any standard model of modern cosmology. The new concept advanced to account for the acceleration is dark energy or quintessence with negative pressure. Most analyses using this new form of energy describe the observed data with great accuracy, although there has been no laboratory confirmation of it. The present work analyzes the consequences of Thomson scattering on Type Ia supernovae data for two significant reasons; (i) recently observed data reveal the existence of sufficient amount of ionized baryonic (hydrogen) dark matter in the intergalactic medium, a necessary ingredient for Thomson scattering, and (ii) its effects have not been considered previously in determining distances to the supernovae from their observed distance moduli. Quantitative results of the present investigation based on observed data and corrected for Thomson scattering are consistent with the prediction of Hubble expansion of the universe. Subject headings: cosmology: theory - distances and redshifts - supernovae, Hubble expansion: constituents of universe - missing dark matter
Spin-gap spectroscopy in a bosonic flux ladder

Ultracold bosonic atoms trapped in a two-leg ladder pierced by a magnetic field provide a minimal and quasi-one-dimensional instance to study the interplay between orbital magnetism and interactions. Using time-dependent matrix-product-state simulations, we investigate the properties of the so-called ‘Meissner’ and ‘vortex’ phases which appear in such a system, focusing on the experimentally accessible observables. We discuss how to experimentally monitor the phase transition, and show that the response to the modulation of the density imbalance between the two legs of the ladder is qualitatively different in the two phases. We argue that this technique can be used as a tool for many-body spectroscopy, allowing us to quantitatively measure the spin gap in the Meissner phase. We finally discuss its experimental implementation.
Energy in Dilaton Gravity in Canonical Approach

An expression for energy in string-inspired dilaton gravity is obtained in canonical approach. The problem of deﬁnition of energy in general relativity has a long history and was repeatedly dis-cussed in diﬀerent aspects [1-6]. In standard gravity interacting with matter, it was shown that for ﬁeld conﬁgurations with asymptotically ﬂat metric with components suﬃciently rapidly decreasing at spacial inﬁnity one can deﬁne a nonnegative expression which is naturally interpreted as energy. In canonical approach, energy is deﬁned as the value of the standard hamiltonian taken on the shell of zero constraints [2, 4, 5].
DEVELOPMENT OF REGIONAL LANDSLIDE SUSCEPTIBILITY MODELS: A FIRST STEP TOWARDS MODEL TRANSFERABILITY

Landslides are a globally pervasive problem with the potential to cause significant fatalities and economic losses. Although landslides are widespread, many at-risk regions may not have the high-quality data or resources used in most landslide susceptibility analyses. This study aims to develop regional susceptibility relationships that are versatile and use publicly available data and open-sourced software. Logistic Regression and Frequency Ratio susceptibility relationships were developed in 23 regions in Washington, Utah, North Carolina, and Kentucky, with a region referring to a unique area and data combination. Regions were diverse in their geology, morphology, climate, and nature and quality of their landslide data. The transferability of select models to regions uninvolved in model development was also tested. The transferred models were trained using data from a single region (single-region cross-validation) or a combination of regions (multi-region cross-validation). Potential landslide contributing factors were all derived from a globally available digital surface model while landslide inventories were publicly available from state geological surveys. The contributing factors considered were elevation, slope, aspect, planform curvature, profile curvature, and topographic position index. Models developed using high-quality landslide data delineating scarps, flanks, and individual slope movements performed very well (AUC 0.764 0.895; AUC = area under relative operating characteristics curve). Models developed using landslide data dominated by deposits performed less well, but at or near an acceptable level (AUC 0.67 – 0.81). Models developed using older, lower quality landslide data did not perform at an acceptable level (AUC 0.63 – 0.64). The results of testing model transferability had acceptable results for some but not all regions (AUC 0.563 0.844). This study is a promising first step in developing generalized landslide susceptibility relationships that can be used in areas that share similar regional scale attributes.
Fluctuation theorems for stochastic dynamics

Fluctuation theorems make use of time reversal to make predictions about entropy production in many-body systems far from thermal equilibrium. Here we review the wide variety of distinct, but interconnected, relations that have been derived and investigated theoretically and experimentally. Significantly, we demonstrate, in the context of Markovian stochastic dynamics, how these different fluctuation theorems arise from a simple fundamental time-reversal symmetry of a certain class of observables. Appealing to the notion of Gibbs entropy allows for a microscopic definition of entropy production in terms of these observables. We work with the master equation approach, which leads to a mathematically straightforward proof and provides direct insight into the probabilistic meaning of the quantities involved. Finally, we point to some experiments that elucidate the practical significance of fluctuation relations.
Collimated radiation in SS 433

Context. The microquasar SS 433 is well known for its precessing, relativistic, and highly collimated baryonic jets, which manifest in its optical spectrum as pairs of hydrogen and helium emission lines moving with large Doppler shifts. Depending on their heating mechanism, the optical jet bullets may serve as a probe of the collimated radiation coming from the inner region close to the compact object, and which is not directly visible to observers on Earth. Aims. We aim to better understand the baryonic jet phenomenon in SS 433, in particular the properties of the optical bullets and their interaction with the ionizing collimated radiation. Methods. The optical interferometer VLTI/GRAVITY has allowed us to spatially resolve the optical jets in SS 433 for the first time. We present here the second such observation taken over three nights in July 2017. In addition, we used the X-shooter spectrograph at VLT to study the optical bullets in SS 433 in detail. Over the full wavelength range 0.3−2.5 μm, we identified up to twenty pairs of jet lines observed simultaneously, which we modeled with the spectral synthesis code Cloudy. Results. GRAVITY reveals elongated exponential-like radial spatial profiles for the optical jets on scales ≲1−10 mas, suggestive of a heating mechanism acting throughout a long portion of the jet and naturally explained by photoionization by the collimated radiation. We also spatially resolve the movement of the optical bullets for the first time, detecting more extended jet components corresponding to previous ejections. Cloudy photoionization models can explain the spatial intensity profiles measured with GRAVITY and the emission line ratios from X-shooter, and constrain the properties of the optical bullets and the ionizing radiation. We find that the latter must peak in the UV with an isotropic luminosity (as inferred by a face-on observer) ∼1041 erg s−1. Provided that the X-ray spectral energy distribution is sufficiently hard, the collimated X-ray luminosity could still be high enough so that the face-on observer would see SS 433 as ultraluminous X-ray source and it would still be compatible with the H/He/He+ ionization balance of the optical bullets. The kinetic power in the optical jets is constrained to 2−20 × 1038 erg s−1, and the extinction in the optical jets to AV = 6.7 ± 0.1. We suggest there may be substantial AV ≳ 1 and structured circumstellar extinction in SS 433, likely arising from dust formed in equatorial outflows.
Orbital and spectral analysis of the benchmark brown dwarf HD 4747B

Context. The study of high-contrast imaged brown dwarfs and exoplanets depends strongly on evolutionary models. To estimate the mass of a directly imaged substellar object, its extracted photometry or spectrum is used and adjusted with model spectra together with the estimated age of the system. These models still need to be properly tested and constrained. HD 4747B is a brown dwarf close to the H burning mass limit, orbiting a nearby (d = 19.25 ± 0.58 pc), solar-type star (G9V); it has been observed with the radial velocity method for over almost two decades. Its companion was also recently detected by direct imaging, allowing a complete study of this particular object. Aims. We aim to fully characterize HD 4747B by combining a well-constrained dynamical mass and a study of its observed spectral features in order to test evolutionary models for substellar objects and to characterize its atmosphere. Methods. We combined the radial velocity measurements of High Resolution Echelle Spectrometer (HIRES) and CORALIE taken over two decades and high-contrast imaging of several epochs from NACO, NIRC2, and SPHERE to obtain a dynamical mass. From the SPHERE data we obtained a low-resolution spectrum of the companion from Y to H band, and two narrow band-width photometric measurements in the K band. A study of the primary star also allowed us to constrain the age of the system and its distance. Results. Thanks to the new SPHERE epoch and NACO archival data combined with previous imaging data and high-precision radial velocity measurements, we were able to derive a well-constrained orbit. The high eccentricity (e = 0.7362 ± 0.0025) of HD 4747B is confirmed, and the inclination and the semi-major axis are derived (i = 47.3 ± 1.6°, a = 10.01 ± 0.21 au). We derive a dynamical mass of mB = 70.0 ± 1.6 MJup, which is higher than a previous study but in better agreement with the models. By comparing the object with known brown dwarfs spectra, we derive a spectral type of L9 and an effective temperature of 1350 ± 50 K. With a retrieval analysis we constrain the oxygen and carbon abundances and compare them with the values from the HR 8799 planets.
The hybrid disks: a search and study to better understand evolution of disks

The increased sensitivity of millimeter-wave facilities now makes possible the detection of low amounts of gas in debris disks. Some of the gas-rich debris disks harbor peculiar properties, with possible pristine gas and secondary generated dust. The origin of the gas in these hybrid disks is strongly debated and the current sample is too sparse to understand this phenomenon. More detections are necessary to increase the statistics on this population. Lying at the final stages of evolution of proto-planetary disks and at the beginning of the debris disk phase, these objects could provide new insight into the processes involved in the making of planetary systems. We carried out a deep survey of the 12CO(2-1) and 12CO(3-2) lines with the APEX and IRAM radiotelescopes in young debris disks selected according to hybrid disk properties. The survey is complemented with a bibliographic study of the ratio between the emission of the gas and the continuum (S_CO/F_cont) in CTTS, Herbig Ae, WTTS, hybrid, and debris disks. Our sub-mm survey comprises 25 stars, including 17 new targets, and we increase the sensitivity limit by a factor 2 on eight sources compared to similar published studies. We report a 4sigma tentative detection of a double-peaked 12CO(2-1) line around HD23642; an eclipsing binary located in the Pleiades. We also reveal a correlation between the emission of the CO gas and the dust continuum from CTTS, Herbig Ae and few debris disks. The observed trend of the gas to dust flux ratio suggests a concurrent dissipation of the dust and gas components. Hybrid disks systematically lie above this trend, suggesting that these systems may witness a transient phase, when the dust has evolved more rapidly than the gas, with a flux ratio S_CO/F_cont enhanced by a factor of between 10 and 100 compared to standard (proto-)planetary disks.
A comparative study of the effects of multimedia training materials on mini CEX scores of internal medicine residents in Isfahan University of Medical Sciences

BACKGROUND: Role of multimedia training materials on Mini-CEX scores of internal medicine residents. We aimed to assess the effect of multi multimedia training materials on Mini-CEX scores of internal medicine residents of Isfahan University of Medical Sciences. SETTINGS AND DESIGN: A quasi-experimental action research study on 1st, 2nd, and 3rd-year internal medicine residents were implemented. MATERIALS AND METHODS: The Mini-CEX test measures students' performance in six core skills necessary for medical practice. Mini-CEX scores of 135 internal medicine residents in 2017–2018 were compared before and after the training with prepared multimedia materials. We used repeated measured ANOVA and Mann–Whitney U test to compare the distribution of Mini-CEX scores across corresponding groups. Analysis was done using the SPSS software version 23 (IBM SPSS Statistics for Windows. Armonk, NY, USA: IBM Corp). RESULTS: The median Mini-CEX score (IQR) of students in preintervention and postintervention groups were 16.14 (5.19) and 19.62 (3.13), respectively. Findings of this study showed a significant increase in mini-CEX scores of the groups who used the multimedia learning material compared to those who did not use it (P < 0.001). CONCLUSIONS: Multimedia learning resources demonstrated a promising influence on internal residents' mini-CEX scores in this study. They demonstrate significantly greater performance after using multimedia learning materials compared to their same-year residents who did not benefit from it. This demonstrates the favorable effect of multimedia on the acquisition of practical skills such as obtaining a history or performing a physical examination.
Modelling of Different On-chip Inductors for Radio Frequency Integrated Circuits

This paper presents a typical frequency-dependent modelling of different on-chip inductors for RFICs design problems. Modern RF circuits often feature on-chip inductors required by modern circuit design. A comparison of different inductor geometrics includes a planar spiral inductor and novel multilayer inductors are analyzed. An electromagnetic model with fewer assumptions than empirical equations and higher efficiency than full-field solvers would be welcome. So would facile comparisons of different inductor structures. This paper describes recent work on the electromagnetic modelling of on-chip inductor structures, applied to the comparison of inductor geometries, including the traditional spiral inductor and a novel multilayer inductor. The electromagnetic modelling of the investigative model is also presented.
Computational modeling of multiphase viscoelastic and elastoviscoplastic flows

In this paper, a three‐dimensional numerical solver is developed for suspensions of rigid and soft particles and droplets in viscoelastic and elastoviscoplastic (EVP) fluids. The presented algorithm is designed to allow for the first time three‐dimensional simulations of inertial and turbulent EVP fluids with a large number particles and droplets. This is achieved by combining fast and highly scalable methods such as an FFT‐based pressure solver, with the evolution equation for non‐Newtonian (including EVP) stresses. In this flexible computational framework, the fluid can be modeled by either Oldroyd‐B, neo‐Hookean, FENE‐P, or Saramito EVP models, and the additional equations for the non‐Newtonian stresses are fully coupled with the flow. The rigid particles are discretized on a moving Lagrangian grid, whereas the flow equations are solved on a fixed Eulerian grid. The solid particles are represented by an immersed boundary method with a computationally efficient direct forcing method, allowing simulations of a large numbers of particles. The immersed boundary force is computed at the particle surface and then included in the momentum equations as a body force. The droplets and soft particles on the other hand are simulated in a fully Eulerian framework, the former with a level‐set method to capture the moving interface and the latter with an indicator function. The solver is first validated for various benchmark single‐phase and two‐phase EVP flow problems through comparison with data from the literature. Finally, we present new results on the dynamics of a buoyancy‐driven drop in an EVP fluid.
Calculation of momentum distribution function of a non-thermal fermionic dark matter

The most widely studied scenario in dark matter phenomenology is the thermal WIMP scenario. Inspite of numerous efforts to detect WIMP, till now we have no direct evidence for it. A possible explanation for this non-observation of dark matter could be because of its very feeble interaction strength and hence, failing to thermalise with the rest of the cosmic soup. In other words, the dark matter might be of non-thermal origin where the relic density is obtained by the so-called freeze-in mechanism. Furthermore, if this non-thermal dark matter is itself produced substantially from the decay of another non-thermal mother particle, then their distribution functions may differ in both size and shape from the usual equilibrium distribution function. In this work, we have studied such a non-thermal (fermionic) dark matter scenario in the light of a new type of U(1)B−L model. The U(1)B−L model is interesting, since, besides being anomaly free, it can give rise to neutrino mass by Type II see-saw mechanism. Moreover, as we will show, it can accommodate a non-thermal fermionic dark matter as well. Starting from the collision terms, we have calculated the momentum distribution function for the dark matter by solving a coupled system of Boltzmann equations. We then used it to calculate the final relic abundance, as well as other relevant physical quantities. We have also compared our result with that obtained from solving the usual Boltzmann (or rate) equations directly in terms of comoving number density, Y. Our findings suggest that the latter approximation is valid only in cases where the system under study is close to equilibrium, and hence should be used with caution.
TMCrack-Net: A U-Shaped Network with a Feature Pyramid and Transformer for Mural Crack Segmentation

The detection of crack information is very important in mural conservation. In practice, the number of ancient murals is scarce, and the difficulty of collecting digital information about murals leads to minimal data being collected. Crack information appears in pictures of paintings, which resembles painting traces and is easy to misidentify. However, the current mainstream semantic segmentation networks directly use the features of the backbone network for prediction, which do not fully use the features at different scales and ignore the differences between the decoder and encoder features. This paper proposes a new U-shaped convolutional neural network with feature pyramids and a transformer called TMCrack-net. Instead of U-Net’s jump-join, an AG-BiFPN network is used, which consists of two modules: a channel cross-fusion (CCT) module with a transformer and a bidirectional feature pyramid network. While fully using the information in different network dimensions, the channel cross-fusion module optimizes the final features of each layer to reduce the confounding effect caused by the fusion of features. For the fusion of multi-scale channel information with decoder features, we designed a fusion module based on a channel attention (called FCA) to guide the fusion of enhanced encoder features with decoder features and reduce the ambiguity between the two feature sets. To demonstrate the effectiveness and generalization of the model, TMCrack-Net was evaluated on the Tang Dynasty tomb chamber mural dataset and Crack500. MIoU values of 0.7731 and 0.7944 were achieved, respectively, which are better than those of other advanced crack detection methods. The method yields accurate segmentation performance and is advantageous for mural painting crack segmentation tasks.
Size effects on generation-recombination noise

We carry out an analytical theory of generation-recombination noise for a two-level resistor model which goes beyond those presently available by including the effects of both space charge fluctuations and diffusion current. Finite size effects are found responsible for the saturation of the low frequency current spectral density at high enough applied voltages. The saturation behavior is controlled essentially by the correlations coming from the long range Coulomb interaction. It is suggested that the saturation of the current fluctuations for high voltage bias constitutes a general feature of generation-recombination noise.