Miracle-dz/UniFAR-FTUs huggingface dataset:
Threaded-field-line Model for the Low Solar Corona Powered by the Alfvén Wave Turbulence

We present an updated global model of the solar corona, including the transition region. We simulate the realistic three-dimensional (3D) magnetic field using the data from the photospheric magnetic field measurements and assume the magnetohydrodynamic (MHD) Alfvén wave turbulence and its nonlinear dissipation to be the only source for heating the coronal plasma and driving the solar wind. In closed-field regions, the dissipation efficiency in a balanced turbulence is enhanced. In the coronal holes, we account for a reflection of the outward-propagating waves, which is accompanied by the generation of weaker counterpropagating waves. The nonlinear cascade rate degrades in strongly imbalanced turbulence, thus resulting in colder coronal holes. The distinctive feature of the presented model is the description of the low corona as almost-steady-state low-beta plasma motion and heat flux transfer along the magnetic field lines. We trace the magnetic field lines through each grid point of the lower boundary of the global corona model, chosen at some heliocentric distance, R = Rb ∼ 1.1R⊙, well above the transition region. One can readily solve the plasma parameters along the magnetic field line from 1D equations for the plasma motion and heat transport together with the Alfvén wave propagation, which adequately describe the physics within the heliocentric distance range R⊙ < R < Rb, in the low solar corona. By interfacing this threaded-field-line model with the full MHD global corona model at r = Rb, we find the global solution and achieve a faster-than-real-time performance of the model on ∼200 cores.
The envelope theory as a pedagogical tool

The envelope theory (ET) is a reliable and easy to implement method to solve time independent Schrödinger-like equations (eigenvalues and eigenvectors). It is particularly useful to solve many-body systems since the computational cost is independent from the number of particles. The purpose of this paper is twofold. First, we want to make known a method that is probably too little used. Second, we also want to show that this method can be used as a pedagogical tool, thanks to its simplicity and the reliable results that can be obtained. To reach these goals, the ET is applied to a simple problem in one dimension, the soft-Coulomb potential −k/x2+d2 , characterised by a bias distance d. Such interaction is used for the study of excitons, electron–hole bound pairs where the two charges are kept separated in two different one-dimensional regions (quantum wires). In addition to its physical interest, this system has never been treated with the ET.
Serendipitous detection of an overdensity of Herschel-SPIRE 250 μm sources south of MRC 1138−26

We report the serendipitous detection of a significant overdensity of Herschel-SPIRE 250 micron sources in the vicinity of MRC1138-26. We use an adaptive kernel density estimate to quantify the significance, including a comparison with other fields. The overdensity has a size of ~3.5-4' and stands out at ~5sigma with respect to the background estimate. No features with similar significance were found in four extragalactic control fields: GOODS-North, Lockman, COSMOS and UDS. The chance of having a similar overdensity in a field with the same number but randomly distributed sources is less than 2%. The clump is also visible as a low surface brightness feature in the Planck 857 GHz map. We detect 76 sources at 250 micron (with a signal-to-noise ratio greater than 3), in a region of 4' radius; 43 of those are above a flux density limit of 20 mJy. This is a factor of 3.6 in excess over the average in the four control fields, considering only the sources above 20 mJy. We also find an excess in the number counts of sources with 250 micron flux densities between 30 and 40 mJy, compared to deep extragalactic blank-field number counts. Assuming a fixed dust temperature (30 K) and emissivity (beta=1.5) a crude, blackbody-derived redshift distribution, zBB, of the detected sources is significantly different from the distributions in the control fields and exhibits a significant peak at zBB ~ 1.5, although the actual peak redshift is highly degenerate with the temperature. We tentatively suggest, based on zBB and the similar S250/S350 colours of the sources within the peak, that a significant fraction of the sources in the clump may be at a similar redshift. Since the overdensity lies ~7' south of the z=2.16 Spiderweb protocluster MRC1138-26, an intriguing possibility (that is presently unverifiable given the data in hand) is that it lies within the same large-scale structure. (abridged)
Theoretical and semiempirical correction to the long-range dispersion power law of stretched graphite

In recent years, intercalated and pillared graphitic systems have come under increasing scrutiny because of their potential for modern energy technologies. While traditional ab initio methods such as the local density approximation give accurate geometries for graphite, they are poorer at predicting physical properties such as cohesive energies and elastic constants perpendicular to the layers because of the strong dependence on long-range dispersion forces. ``Stretching'' the layers via pillars or intercalation further highlights these weaknesses. We use the ideas developed by Dobson et al. [Phys. Rev. Lett. 96, 073201 (2006)] as a starting point to show that the asymptotic ${C}_{3}{D}^{\ensuremath{-}3}$ dependence of the cohesive energy on layer spacing $D$ in bigraphene is universal to all graphitic systems with evenly spaced layers. At spacings appropriate to intercalates, this differs from and begins to dominate the ${C}_{4}{D}^{\ensuremath{-}4}$ power law for dispersion that has been widely used previously. The corrected power law (and a calculated ${C}_{3}$ coefficient) is then applied to the semiempirical approach of Hasegawa and Nishidate (HN) [Phys. Rev. B 70, 205431 (2004)]; however, a meaningful result cannot be obtained in this approach. A modified, physically motivated semiempirical method adding some ${C}_{4}{D}^{\ensuremath{-}4}$ effects allows the HN method to be employed and gives an absolute increase of about 2%\char21{}3% to the predicted cohesive energy, while still maintaining the correct ${C}_{3}{D}^{\ensuremath{-}3}$ asymptotics.
Evidence of diamagnetic fluctuations above Tc in BaFe2-xCoxAs2 single crystals

Increasing doping concentration (x) in Pnictide superconductors results in the suppression of long range magnetic order and the emergence of superconductivity. While doping destroys long range magnetic order however the effect if any of the surviving magnetic fluctuations on superconductivity in Pnictides is currently not well understood. In optimally doped BaFe2-xCoxAs2 single crystals, below Tc we observe local regions with positive magnetization coexisting along with superconductivity at low applied magnetic fields (H). With increasing H the positive magnetization response gets weaker and the robust superconducting diamagnetic response appears. The normal state is found to be inhomogeneous with regions having local diamagnetic response embedded in a positive magnetization background. Estimates of the superconducting fraction in the normal state shows it maximizes for the optimally doped crystal. We construct a doping dependent H - T diagram identifying different fluctuation regimes and our data suggests a close correlation between magnetic and superconducting fluctuations in BaFe2-xCoxAs2.
Indications of a sub-linear and non-universal Kennicutt-Schmidt relationship

We estimate the parameters of the Kennicutt–Schmidt (KS) relationship, linking the star formation rate (ΣSFR) to the molecular gas surface density (Σmol), in the Survey Toward Infrared-Bright Nearby Galaxies sample of nearby disc galaxies using a hierarchical Bayesian method. This method rigorously treats measurement uncertainties, and provides accurate parameter estimates for both individual galaxies and the entire population. Assuming standard conversion factors to estimate ΣSFR and Σmol from the observations, we find that the KS parameters vary between galaxies, indicating that no universal relationship holds for all galaxies. The KS slope of the whole population is 0.76, with the 2σ range extending from 0.58 to 0.94. These results imply that the molecular gas depletion time is not constant, but varies from galaxy-to-galaxy, and increases with the molecular gas surface density. Therefore, other galactic properties besides just Σmol affect ΣSFR, such as the gas fraction or stellar mass. The non-universality of the KS relationship indicates that a comprehensive theory of star formation must take into account additional physical processes that may vary from galaxy to galaxy.
Weighing votes in human-machine collaboration for hazard recognition: Inferring hazard perceptual threshold and decision confidence from electroencephalogram wavelets

Purpose: Human-machine collaboration is a promising strategy to improve hazard inspection. However, research on the effective integration of opinions from humans with machines for optimal group decision making is lacking. Hence, considering the benefits of a brain-computer interface (BCI) to enable intuitive commutation, this study proposes a novel method to predict human hazard response choices and decision confidence from brain activities for a superior confidence-weighted voting strategy. Methodology: First, we developed a Bayesian inference-based algorithm to ascertain the decision threshold above which a hazard is reported from human brain signals. This method was tested empirically with electroencephalogram (EEG) data collected in a laboratory setting and cross-validated using behavioral indices of the signal detection theory. Subsequently, based on numerical simulations, the decision criteria for low-, medium-, and high-confidence level differentiations characterized by parietal alpha-band EEG power were determined. Findings : The investigated hazard recognition task was described as a process of probabilistic inference involving a decision uncertainty evaluation. The results demonstrated the feasibility of EEG measurements in observing human internal representations of hazard discrimination. Moreover, the optimal criteria to differentiate between low-, medium-, and high-confidence levels were obtained by benchmarking against an optimal Bayesian observer. Originality: This research demonstrates the potential of a BCI as an effective channel for telecommunication, laying the foundation for the design of future hazard detection techniques in the collaborative human-machine systems research field.
Optimal Designs of Two-Phase Case-Control Studies for General Predictor Effects

Under two-phase designs, the outcome and several covariates and confounders are measured in the first phase, and a new predictor of interest, which may be costly to collect, can be measured on a subsample in the second phase, without incurring the costs of recruiting subjects. Information in the first phase can be used to select the second-phase subsample with the goal of improving the efficiency in testing and estimating the effect of the new predictor on the outcome. Past studies have focused on optimal two-phase sampling schemes for statistical inference on local ($\beta = o(1)$) effects of the predictor of interest. Here we extend the two-phase designs with an optimal sampling scheme in case-control studies for estimation predictor effects with pseudo conditional likelihood estimators. The proposed approach is applicable to both local and non-local effects. We demonstrate that the proposed sampling scheme can lead to a substantive improvement in the estimation of the parameter of interest simulation studies and an analysis of data from 170 patients hospitalized for COVID-19.
S0 galaxies in the Coma cluster: environmental dependence of the S0 offset from the Tully–Fisher relation

We present deep Gemini Multi-Object Spectrograph long-slit spectroscopy of 15 Coma cluster S0 galaxies, and extract kinematic properties along the major axis to several times the disc scalelength. Supplementing our data set with previously published data, we create a combined sample of 29 Coma S0s, as well as a comparison sample of 38 Coma spirals. Using photometry from the Sloan Digital Sky Survey and Two Micron All Sky Survey, we construct the Tully–Fisher relation (TFR; luminosity versus maximum rotational velocity) for S0 galaxies. At fixed rotational velocity, the Coma S0 galaxies are on average fainter than Coma spirals by 1.10 ± 0.18, 0.86 ± 0.19 and 0.83 ± 0.19 mag in the g, i and Ks bands, respectively. The typical S0 offsets remain unchanged when calculated relative to large field-galaxy spiral samples. The observed offsets are consistent with a simple star formation model in which S0s are identical to spirals until abrupt quenching occurs at some intermediate redshift. The offsets form a continuous distribution tracing the time since the cessation of star formation, and exhibit a strong correlation (>6σ) with residuals from the optical colour–magnitude relation. Typically, S0s which are fainter than average for their rotational velocity are also redder than average for their luminosity. The S0 TFR offset is also correlated with both the projected cluster-centric radius and the Σ (projected) local density parameter. Since current local environment is correlated with time of accretion into the cluster, our results support a scenario in which transformation of spirals to S0s is triggered by cluster infall.
ANALYTIC APPROXIMATE SEISMOLOGY OF PROPAGATING MAGNETOHYDRODYNAMIC WAVES IN THE SOLAR CORONA

Observations show that propagating magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. The technique of MHD seismology uses the wave observations combined with MHD wave theory to indirectly infer physical parameters of the solar atmospheric plasma and magnetic field. Here, we present an analytical seismological inversion scheme for propagating MHD waves. This scheme uses the observational information on wavelengths and damping lengths in a consistent manner, along with observed values of periods or phase velocities, and is based on approximate asymptotic expressions for the theoretical values of wavelengths and damping lengths. The applicability of the inversion scheme is discussed and an example is given.
Counterfactual inference for sequential experiments

We consider after-study statistical inference for sequentially designed experiments wherein multiple units are assigned treatments for multiple time points using treatment policies that adapt over time. Our goal is to provide inference guarantees for the counterfactual mean at the smallest possible scale -- mean outcome under different treatments for each unit and each time -- with minimal assumptions on the adaptive treatment policy. Without any structural assumptions on the counterfactual means, this challenging task is infeasible due to more unknowns than observed data points. To make progress, we introduce a latent factor model over the counterfactual means that serves as a non-parametric generalization of the non-linear mixed effects model and the bilinear latent factor model considered in prior works. For estimation, we use a non-parametric method, namely a variant of nearest neighbors, and establish a non-asymptotic high probability error bound for the counterfactual mean for each unit and each time. Under regularity conditions, this bound leads to asymptotically valid confidence intervals for the counterfactual mean as the number of units and time points grows to $\infty$ together at suitable rates. We illustrate our theory via several simulations and a case study involving data from a mobile health clinical trial HeartSteps.
Characterizing a cluster’s dynamic state using a single epoch of radial velocities

Context. Radial velocity measurements can be used to constrain the dynamical state of a stellar cluster. However, for clusters with velocity dispersions smaller than a few kms −1 the observed radial velocity distribution tends to be dominated by the orbital motions of binaries rather than the stellar motions through the potential well of the cluster. Aims. Our goal is to characterize the intrinsic velocity distribution of a cluster from a single epoch of radial velocity data even for a cluster with a velocity dispersion of a fraction of a kms −1 . Methods. We investigate a maximum likelihood procedure, which has been pioneered in the literature about ten years ago. Assuming a period, mass ratio, and eccentricity distribution for the binaries in the observed cluster this procedure fitsa dynamical model describing the velocity distribution for the single stars and center of masses of the binaries, simultaneously with the radial velocities caused by binary orbital motions, using all the information available in the observed velocity distribution. We test the capability of this procedure to reproduce the velocity dispersion of an observed cluster, using radial velocity data of an open cluster and Monte Carlo simulations. Results. We find that the fits to the intrinsic velocity distribution depend only weakly on the binary properties assumed, so the uncertainty in thefittedparameters tends to be dominated by statisticaluncertainties. Based on a largesuite of Monte Carlo simulations we provide an estimate of how these statistical uncertainties vary with the velocity dispersion, binary fraction, and the number of observed stars, which can be used to estimate the sample size needed to reach a specific accuracy. Finally we test the method on the well-studied open cluster NGC 188, showing that it can successfully reproduce a velocity dispersion of only 0.5kms −1 using a single epoch of the multi-epoch radial velocity data. Conclusions. If the binary period, mass ratio, and eccentricity distribution of the observed stars are roughly known, this procedure can be used to correct for the effect of binary orbital motions on an observed velocity distribution. This allows for the study of the dynamical state of a stellar cluster with a small velocity dispersion from a single epoch of radial velocity data.
The Age Distribution of Potential Intelligent Life in the Milky Way

We investigated the habitability of the Milky Way, making use of recent observational analysis on the prevalence of Earth-sized planets, in order to estimate where and when potentially habitable star systems may have formed over the course of the Galaxy's history. We were then able to estimate the age distribution of potential intelligent life in our Galaxy using our own evolution and the age of the Sun as a proxy. To do this we created a galactic chemical evolution model and applied the following habitability constraints to the Sun-like (G-type) stars formed in our model: an environment free from life-extinguishing supernovae, a high enough metallicity for Earth-sized planet formation and sufficient time for the evolution of complex life. We determined a galactic habitable zone as the region containing all the potentially habitable star systems in our model. Our galactic habitable zone contains stars formed between 11 and 3.8 billion years ago at radial distances of between 7 and 14 kiloparsecs. We found that most potentially habitable star systems are much older than the Sun and located farther from the galactic centre. By comparing the ages of these systems we estimated that 77% of potentially habitable star systems are on average 3.13 billion years older than the Sun. This suggests that any intelligent life in the Galaxy is likely to be incredibly more advanced than we are assuming that they have evolved under similar timescales than we have. Implications and limitations of our study are discussed.
Some models of geometric noncommutative general relativity

Using Fedosov theory of deformation quantization of endomorphism bundle we construct several models of pure geometric, deformed vacuum gravity, corresponding to arbitrary symplectic noncommutativity tensor. Deformations of Einstein-Hilbert and Palatini actions are investigated. Coordinate covariant field equations are derived up to the second order of the deformation parameter. For some models they are solved and explicit corrections to an arbitrary Ricci-flat metric are pointed out. The relation to the theory of Seiberg-Witten map is also studied and the correspondence to the spacetime noncommutativity described by Fedosov *-product of functions is explained.
SHELS: OPTICAL SPECTRAL PROPERTIES OF WISE 22 μm SELECTED GALAXIES

We use a dense, complete redshift survey, the Smithsonian Hectospec Lensing Survey (SHELS), covering a 4 deg2 region of a deep imaging survey, the Deep Lens Survey (DLS), to study the optical spectral properties of Wide-field Infrared Survey Explorer (WISE) 22 μm selected galaxies. Among 507 WISE 22 μm selected sources with (S/N)22 μm ⩾ 3 (≈S22 μm ≳ 2.5 mJy), we identify the optical counterparts of 481 sources (∼98%) at R < 25.2 in the very deep, DLS R-band source catalog. Among them, 337 galaxies at R < 21 have SHELS spectroscopic data. Most of these objects are at z < 0.8. The infrared (IR) luminosities are in the range 4.5 × 108(L☉) ≲ LIR ≲ 5.4 × 1012(L☉). Most 22 μm selected galaxies are dusty star-forming galaxies with a small (<1.5) 4000 Å break. The stacked spectra of the 22 μm selected galaxies binned in IR luminosity show that the strength of the [O iii] line relative to Hβ grows with increasing IR luminosity. The optical spectra of the 22 μm selected galaxies also show that there are some (∼2.8%) unusual galaxies with very strong [Ne iii] λ3869, 3968 emission lines that require hard ionizing radiation such as active galactic nuclei (AGNs) or extremely young massive stars. The specific star formation rates (sSFRs) derived from the 3.6 and 22 μm flux densities are enhanced if the 22 μm selected galaxies have close late-type neighbors. The sSFR distribution of the 22 μm selected galaxies containing AGNs is similar to the distribution for star-forming galaxies without AGNs. We identify 48 dust-obscured galaxy candidates with large (≳ 1000) mid-IR to optical flux density ratio. The combination of deep photometric and spectroscopic data with WISE data suggests that WISE can probe the universe to z ∼ 2.
Fast spectral variability from Cygnus X-1

We have developed an algorithm that, starting with the observed properties of the X-ray spectrum and fast variability of an X-ray binary, allows the production of synthetic data reproducing observables such as power density spectra and time lags as well as their energy dependence. This further allows us to reconstruct the variability of the parameters of the energy spectrum and to reduce substantially the effects of Poisson noise, helping in studying fast spectral variations. We have applied the algorithm to the Rossi X-ray Timing Explorer data of the black hole binary Cygnus X-1, fitting the energy spectrum with a simplified power-law model. We found that the distribution of the power-law spectral indices on time-scales as low as 62 ms is limited between 1.6 and 1.8. The spectra index is positively correlated with the flux even on such time-scales.