Miracle-dz/UniFAR-FTUs huggingface dataset:
Competition between shock and turbulent heating in coronal loop system

2.5-dimensional magnetohydrodynamic (MHD) simulations are performed with high spatial resolution in order to distinguish between competing models of the coronal heating problem. A single coronal loop powered by Alfven waves excited in the photosphere is the target of the present study. The coronal structure is reproduced in our simulations as a natural consequence of the transportation and dissipation of Alfven waves. Further, the coronal structure is maintained as the spatial resolution is changed from 25 to 3 km, although the temperature at the loop top increases with the spatial resolution. The heating mechanisms change gradually across the magnetic canopy at a height of 4 Mm. Below the magnetic canopy, both the shock and the MHD turbulence are dominant heating processes. Above the magnetic canopy, the shock heating rate reduces to less than 10 % of the total heating rate while the MHD turbulence provides significant energy to balance the radiative cooling and thermal conduction loss or gain. The importance of compressibility shown in the present study would significantly impact on the prospects of successful MHD turbulence theory in the solar chromosphere.
High-resolution spectroscopic observations of the new CEMP-s star CD −50°776

Carbon enhanced metal poor (CEMP) stars are a particular class of low metalicity halo stars whose chemical analysis may provide important constrains to the chemistry evolution of the Galaxy and to the models of mass transfer and evolution of components in binary systems. Here, we present a detailed analysis of the CEMP star CD-50$^\circ$776, using high resolution optical spectroscopy. We found that CD-50$^\circ$776 has a metalicity [Fe/H]=-2.31 and a carbon abundance [C/Fe]=+1.21. Analyzing the s-process elements and the europium abundances, we show that this star is actually a CEMP-s star, based on the criteria set in the literature to classify these chemically peculiar objects. We also show that CD-50$^\circ$776 is a lead star, since it has a ratio [Pb/Ce]=+0.97. In addition, we show that CD-50$^\circ$776 develops radial velocity variations that may be attributed to the orbital motion in a binary system. The abundance pattern of CD-50$^\circ$776 is discussed and compared to other CEMP-s stars already reported in the literature to show that this star is a quite exceptional object among the CEMP stars, particularly due to its low nitrogen abundance. Explaining this pattern may require to improve the nucleosynthesis models, and the evolutionary models of mass transfer and binary interaction.
Classifying CP transformations according to their texture zeros: theory and implications

We provide a classification of generalized CP symmetries preserved by the neutrino mass matrix according to the number of zero entries in the associated transformation matrix. We determine the corresponding constrained form of the lepton mixing matrix, characterized by correlations between the mixing angles and the CP violating phases. We compare with the corresponding restrictions from current neutrino oscillation global fits and show that, in some cases, the Dirac CP phase characterizing oscillations is highly constrained. Implications for current and upcoming long baseline neutrino oscillation experiments T2K, NO$\nu$A and DUNE, as well as neutrinoless double beta decay experiments are discussed. We also study the cosmological implications of such schemes for leptogenesis.
Common origin for Hercules-Aquila and Virgo Clouds inGaiaDR2

We use a sample of ~350 RR Lyrae stars with radial velocities and Gaia DR2 proper motions to study orbital properties of the Hercules-Aquila Cloud (HAC) and Virgo Over-density (VOD). We demonstrate that both structures are dominated by stars on highly eccentric orbits, with peri-centres around ~1 kpc and apo-centres between 15 and 25 kpc from the Galactic centre. Given that the stars in the HAC and the VOD occupy very similar regions in the space spanned by integrals of motion, we conclude that these diffuse debris clouds are part of the same accretion event. More precisely, these inner halo sub-structures likely represent two complementary not-fully-mixed portions of an ancient massive merger, also known as the "sausage" event.
The site conditions of the Guo Shou Jing Telescope

The weather at the Xinglong Observing Station, where the Guo Shou Jing Telescope (GSJT) is located, is strongly affected by the monsoon climate in northeast China. The LAMOST survey strategy is constrained by these weather patterns. We present statistics on observing hours from 2004 to 2007, and the sky brightness, seeing, and sky transparency from 1995 to 2011 at the site. We investigate effects of the site conditions on the survey plan. Operable hours each month show a strong correlation with season: on average there are eight operable hours per night available in December, but only one—two hours in July and August. The seeing and the sky transparency also vary with season. Although the seeing is worse in windy winters, and the atmospheric extinction is worse in the spring and summer, the site is adequate for the proposed scientific program of the LAMOST survey. With a Monte Carlo simulation using historical data on the site condition, we find that the available observation hours constrain the survey footprint from 22h to 16h in right ascension; the sky brightness allows LAMOST to obtain a limiting magnitude of V = 19.5 mag with S/N=10.
Enhancing Active Learning with Weak Supervision and Transfer Learning by Leveraging Information and Knowledge Sources

One of the major limitations of deploying a machine learning model is the availability of labeled training data and the resulting expensive annotation process. Although active learning (AL) methods may reduce the annotation cost by actively selecting the most-useful instances, a costly human annotator usually provides the labels. Therefore, even with AL, we still consider the annotation process to be time-consuming and expensive. Besides human annotators, though, companies often have a vast amount of information and knowledge sources available that can generate low-cost labels (e.g., a black-box model) or improve the learning process (e.g., a pre-trained model). We present a novel approach that enhances AL with weak supervision (WS) and transfer learning (TL) to reduce the annotation cost by leveraging these sources. Specifically, we consider a black-box model like a rule-based system as an error-prone and weakly-supervised annotator that inexpensively provides labels. We estimate its performance with an annotator model to decide whether a human annotation is required. Additionally, we utilize unlabeled internal and external data by transferring knowledge from a pre-trained model to the AL cycle. We sequentially investigate the impact of WS and TL on annotation cost and model performance in an AL cycle through a use case. Our evaluation shows that our approach can reduce annotation cost by 51% while achieving nearly identical model performance compared to a traditional AL approach.
Periodic Exponential Shear of Complex Fluids

We define a class of flows with exponential kinematics termed P eriodic Exponential Shear (PES) flow which involve periodic exponential stretching of fluid elements along wit h their rotation. We exhibit analytical and numerical resul ts for PES flow by using the Oldroyd-B model for viscoelastic flui ds. We calculate the growth in the shear and the normal stresses analytically as well as demonstrate that repeated application of the flow leads to stable oscillatory shear and normal stresses. We define a material function applicable to a periodic, unsteady shear flow and show numerically that this material function exhibits deformation-rate thi ckening behavior for viscoelastic fluids subject to PES flow. We demonstrate the feasibility of PES flow by presenting prel iminary experimental results from a controlled-strain rate rheometer, using a Newtonian mineral oil.
Polarization of the changing-look quasar J1011+5442

If the disappearance of the broad emission lines observed in changing-look quasars were caused by the obscuration of the quasar core through moving dust clouds in the torus, high linear polarization typical of type 2 quasars would be expected. We measured the polarization of the changing-look quasar J1011+5442 in which the broad emission lines have disappeared between 2003 and 2015. We found a polarization degree compatible with null polarization. This measurement suggests that the observed change of look is not due to a change of obscuration hiding the continuum source and the broad line region, and that the quasar is seen close to the system axis. Our results thus support the idea that the vanishing of the broad emission lines in J1011+5442 is due to an intrinsic dimming of the ionizing continuum source that is most likely caused by a rapid decrease in the rate of accretion onto the supermassive black hole.
Results from the first heavy ion run at the LHC

Early November 2010, the LHC collided for the first time heavy ions, Pb on Pb, at a centre-of-mass energy of 2.76 TeV/nucleon. This date marked both the end of almost 20 years of preparing for nuclear collisions at the LHC, as well as the start of a new era in ultra-relativistic heavy ion physics at energies exceeding previous machines by more than an order of magnitude. This contribution summarizes some of the early results from all three experiments participating in the LHC heavy ion program (ALICE, ATLAS, and CMS), which show that the high density matter created at the LHC, while much hotter and larger, still behaves like the very strongly interacting, almost perfect liquid discovered at RHIC. Some surprising and even puzzling results are seen in particle ratios, jet-quenching, and Quarkonia suppression observables. The overall experimental conditions at the LHC, together with its set of powerful and state-of-the-art detectors, should allow for precision measurements of quark-gluon-plasma parameters like viscosity and opacity.
The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters – XVII. Public Catalogue Release

In this paper we present the astro-photometric catalogues of 56 globular clusters and one open cluster. Astrometry and photometry are mainly based on images collected within the "HST Legacy Survey of Galactic Globular Clusters: Shedding UV Light on Their Populations and Formation" (GO-13297, PI:~Piotto), and the "ACS Survey of Galactic Globular Clusters" (GO-10775, PI:~Sarajedini). For each source in the catalogues for which we have reliable proper motion we also publish a membership probability for separation of field and cluster stars. These new catalogues, which we make public in Mikulski Archive for Space Telescopes, replace previous catalogues by Paper VIII of this series.
THE ACS NEARBY GALAXY SURVEY TREASURY. VIII. THE GLOBAL STAR FORMATION HISTORIES OF 60 DWARF GALAXIES IN THE LOCAL VOLUME

We present uniformly measured star formation histories (SFHs) of 60 nearby (D ≲ 4 Mpc) dwarf galaxies based on color–magnitude diagrams of resolved stellar populations from images taken with the Hubble Space Telescope and analyzed as part of the ACS Nearby Galaxy Survey Treasury program (ANGST). This volume-limited sample contains 12 dwarf spheroidal (dSph)/dwarf elliptical (dE), 5 dwarf spiral, 28 dwarf irregular (dI), 12 dSph/dI (transition), and 3 tidal dwarf galaxies. The sample spans a range of ∼10 mag in MB and covers a wide range of environments, from highly interacting to truly isolated. From the best-fit SFHs, we find three significant results for dwarf galaxies in the ANGST volume: (1) the majority of dwarf galaxies formed the bulk of their mass prior to z ∼ 1, regardless of current morphological type; (2) the mean SFHs of dIs, transition dwarf galaxies (dTrans), and dSphs are similar over most of cosmic time, and only begin to diverge a few Gyr ago, with the clearest differences between the three appearing during the most recent 1 Gyr; and (3) the SFHs are complex and the mean values are inconsistent with simple SFH models, e.g., single bursts, constant star formation rates (SFRs), or smooth, exponentially declining SFRs. The mean SFHs show clear divergence from the cosmic SFH at z ≲ 0.7, which could be evidence that low-mass systems have experienced delayed star formation relative to more massive galaxies. The sample shows a strong density–morphology relationship, such that the dSphs in the sample are less isolated than the dIs. We find that the transition from a gas-rich to gas-poor galaxy cannot be solely due to internal mechanisms such as stellar feedback, and instead is likely the result of external mechanisms, e.g., ram pressure and tidal stripping and tidal forces. In terms of their environments, SFHs, and gas fractions, the majority of the dTrans appear to be low-mass dIs that simply lack Hα emission, similar to Local Group (LG) dTrans DDO 210. However, a handful of dTrans have remarkably low gas fractions, suggesting that they have nearly exhausted their gas supply, analogous to LG dTrans such as Phoenix. Finally, we have also included extensive exploration of uncertainties in the SFH recovery method, including the optimization of time resolution, the effects of photometric depth, and impact of systematic uncertainties due to the limitations in current stellar evolution models.
UNVEILING THE NEW GENERATION OF STARS IN NGC 604 WITH GEMINI-NIRI

We present a near-infrared study focused on the detection and characterization of the youngest stellar component of the NGC 604 giant star-forming region in the Triangulum galaxy (M 33). By means of color–color diagrams derived from the photometry of JHKs images taken with the Gemini Near Infrared Imaging and Spectrometer (NIRI), we have found 68 candidate massive young stellar objects. The spatial distribution of these sources matches the areas where previous studies suggested that star formation might be taking place, and the high spatial resolution of our deep NIRI imaging allows us to pinpoint the star-forming knots. An analysis of the fraction of objects that show infrared excess suggests that the star formation is still active, supporting the presence of a second generation of stars being born, although the evidence for or against sequential star formation does not seem to be conclusive.
Searching for primordial non-Gaussianity in Planck CMB maps using a combined estimator

The extensive search for deviations from Gaussianity in cosmic microwave background radiation (CMB) data is very important due to the information about the very early moments of the universe encoded there. Recent analyses from Planck CMB data do not exclude the presence of non-Gaussianity of small amplitude, although they are consistent with the Gaussian hypothesis. The use of different techniques is essential to provide information about types and amplitudes of non-Gaussianities in the CMB data. In particular, we find interesting to construct an estimator based upon the combination of two powerful statistical tools that appears to be sensitive enough to detect tiny deviations from Gaussianity in CMB maps. This estimator combines the Minkowski functionals with a Neural Network, maximizing a tool widely used to study non-Gaussian signals with a reinforcement of another tool designed to identify patterns in a data set. We test our estimator by analyzing simulated CMB maps contaminated with different amounts of local primordial non-Gaussianity quantified by the dimensionless parameter f NL. We apply it to these sets of CMB maps and find ≳ 98% of chance of positive detection, even for small intensity local non-Gaussianity like f NL = 38±18, the current limit from Planck data for large angular scales. Additionally, we test the suitability to distinguish between primary and secondary non-Gaussianities: first we train the Neural Network with two sets, one of nearly Gaussian CMB maps (|f NL| ⩽ 10) but contaminated with realistic inhomogeneous Planck noise (i.e., secondary non-Gaussianity) and the other of non-Gaussian CMB maps, that is, maps endowed with weak primordial non-Gaussianity (28 ⩽ f NL ⩽ 48); after that we test an ensemble composed of CMB maps either with one of these non-Gaussian contaminations, and find out that our method successfully classifies ∼ 95% of the tested maps as being CMB maps containing primordial or secondary non-Gaussianity. Furthermore, we analyze the foreground-cleaned Planck maps obtaining constraints for non-Gaussianity at large-angles that are in good agreement with recent constraints. Finally, we also test the robustness of our estimator including cut-sky masks and realistic noise maps measured by Planck, obtaining successful results as well.
Threshold singularities in the one-dimensional Hubbard model

We consider excitations with the quantum numbers of a hole in the one-dimensional Hubbard model below half-filling. We calculate the finite-size corrections to the energy. The results are then used to determine threshold singularities in the single-particle Green's function for commensurate fillings. We present the analogous results for the Yang-Gaudin model (electron gas with $\ensuremath{\delta}$-function interactions).
Extracting Structured Knowledge from Dutch Legal Texts: A Rule-based Approach

Legal texts are difficult to interpret, and its interpretation depends on the knowledge and experience of the legal expert. Formalising interpretations can improve transparency. However, creating formalisations of legal texts is labour-intensive, and automatically creating them is still a challenge. Previous work showed that rule-based systems have mixed success on Dutch legal texts. They use complex rule systems for specific cases, making them hard to compare. Because of the lack of analysis, the success of these methods is also unclear. In this paper, we propose a new rule-based architecture for detecting the different roles of Flint frames, a knowledge representation language which aims to be a generic and less task-dependent language. The rules in this architecture are based on Part-of-Speech tags and universal dependency tags. Our analysis shows that this combination yields more precise extraction of the roles of Flint frames than previous methods, and the use of universal dependency tags allows this method to also be applied to other languages. For further improvement we suggest extending the rules for extracting the recipient role, add rules for recognising complex relative clauses, and testing this framework on English legal texts.
Parameter Selection in Gaussian Process Interpolation: An Empirical Study of Selection Criteria

This article revisits the fundamental problem of parameter selection for Gaussian process interpolation. By choosing the mean and the covariance functions of a Gaussian process within parametric families, the user obtains a family of Bayesian procedures to perform predictions about the unknown function, and must choose a member of the family that will hopefully provide good predictive performances. We base our study on the general concept of scoring rules, which provides an effective framework for building leave-one-out selection and validation criteria, and a notion of extended likelihood criteria based on an idea proposed by Fasshauer and co-authors in 2009, which makes it possible to recover standard selection criteria such as, for instance, the generalized cross-validation criterion. Under this setting, we empirically show on several test problems of the literature that the choice of an appropriate family of models is often more important than the choice of a particular selection criterion (e.g., the likelihood versus a leave-one-out selection criterion). Moreover, our numerical results show that the regularity parameter of a Mat{\'e}rn covariance can be selected effectively by most selection criteria.
Universality of Dzyaloshinskii-Moriya interaction effect over domain-wall creep and flow regimes

Chirality causes diverse phenomena in nature such as the formation of biological molecules, antimatters, non-collinear spin structures, and magnetic skyrmions. The chirality in magnetic materials is often caused by the noncollinear exchange interaction, called the Dzyaloshinskii-Moriya interaction (DMI). The DMI produces topological spin alignments such as the magnetic skyrmions and chiral domain walls (DWs). In the chiral DWs, the DMI generates an effective magnetic field $H_{DMI}$, resulting in a peculiar DW speed variation in the DW creep regime. However, the role of $H_{DMI}$ over the different DW-dynamics regimes remains elusive, particularly due to recent observation of distinct behaviors between the creep and flow regimes. We hereby demonstrate experimentally that the role of $H_{DMI}$ is invariant over the creep and flow regimes. In the experiments, the pure DMI effect is quantified by decomposing the symmetric and antisymmetric contributions of the DW motion. The results manifest that the antisymmetric contribution vanishes gradually across the creep and flow regimes, revealing that the symmetric contribution from $H_{DMI}$ is unchanged. Though the DW dynamics is governed by distinct mechanisms, the present observation demonstrates the uniqueness of the DMI effect on the DWs over the creep and flow regimes.
Exposure Doesn’t Pay the Bills Artistic Production on Streaming Platforms Under Algorithmically-Induced Audience Uncertainty

ContentstreamingplatformslikeYouTubeandTikTokplayanimportantpartinthelivesofmany. This papercontributestoexistingliteraturebyexploringtheoptimalquality-quantitytradeoffofacontentcre-atoronastreamingplatform.Thispapercreatesamodelofhowacreator’srevenueevolveswhenaudi-encesizeisdeterminedbyanunpredictablealgorithm.Solvingthismodelusingdynamicprogramming predictstheemergenceofathree-phasequalitystrategy.Smallcreatorswhoareunlikelytobediscovered choosehighquality,buddingcreatorschooselowqualitytoquicklygrowafollowing,andestablished creatorsreturntohighquality.Thispapercontributestothegrowingstreamingliteraturebyfocusingon whatdrivesthecontentcreator’sdecisionsovertimeunderaudienceuncertainty.
Signatures of nonlocal Cooper-pair transport and of a singlet-triplet transition in the critical current of a double-quantum-dot Josephson junction

We study the critical Josephson current flowing through a double quantum dot weakly coupled to two superconducting leads. We use analytical as well as numerical methods to investigate this setup in the limit of small and large bandwidth leads in all possible charging states, where we account for on-site interactions exactly. Our results provide clear signatures of nonlocal spin-entangled pairs, which support interpretations of recent experiments [R. S. Deacon, A. Oiwa, J. Sailer, S. Baba, Y. Kanai, K. Shibata, K. Hirakawa, and S. Tarucha, Nat. Commun. 6, 7446 (2015)]. In addition, we find that the ground state with one electron on each quantum dot can undergo a tunable singlet-triplet phase transition in the regime where the superconducting gap in the leads is not too large, which gives rise to an additional new signature of nonlocal Cooper-pair transport.
Constraining the evolution of stellar rotation using solar twins

The stellar Rotation $vs.$ Age relation is commonly considered as a useful tool to derive reliable ages for Sun-like stars. However, in the light of \kepler\ data, the presence of apparently old and fast rotators that do not obey the usual gyrochronology relations led to the hypothesis of weakened magnetic breaking in some stars. In this letter, we constrain the solar rotation evolutionary track using solar twins. Predicted rotational periods as a function of mass, age, [Fe/H] and given critical Rossby number ($Ro_{\rm crit}$) were estimated for the entire rotational sample. Our analysis favors the smooth rotational evolution scenario and suggests that, if the magnetic weakened breaking scenario takes place at all, it should arise after $Ro_{\rm crit}\gtrsim2.29$ or ages $\gtrsim$5.3 Gyr (at 95$\%$ confidence level).