Miracle-dz/UniFAR-FTUs huggingface dataset:
The chemical compositions of solar twins in the open cluster M67

Stars in open clusters are expected to share an identical abundance pattern. Establishing the level of chemical homogeneity in a given open cluster deserves further study as it is the basis of the concept of chemical tagging to unravel the history of theMilkyWay.M67 is particularly interesting given its solar metallicity and age as well as being a dense cluster environment.We conducted a strictly line-by-line differential chemical abundance analysis of two solar twins in M67: M67-1194 and M67-1315. Stellar atmospheric parameters and elemental abundances were obtained with high precision using Keck/High Resolution Echelle Spectrometer spectra. M67-1194 is essentially identical to the Sun in terms of its stellar parameters. M67-1315 is warmer than M67-1194 by ≈150 K as well as slightly more metal-poor than M67-1194 by ≈0.05 dex. M67-1194 is also found to have identical chemical composition to the Sun, confirming its solar-twin nature. The abundance ratios [X/Fe] of M67-1315 are similar to the solar abundances for elements with atomic number Z ≤ 30, while most neutron-capture elements are enriched by ≈0.05 dex, which might be attributed to enrichment from a mixture of asymptotic giant branch ejecta and r-process material. The distinct chemical abundances for the neutron-capture elements in M67-1315 and the lower metallicity of this star compared to M67-1194, indicate that the stars in M67 are likely not chemically homogeneous. This poses a challenge for the concept of chemical tagging since it is based on the assumption of stars forming in the same star-forming aggregate. (Less)
THE GLOBULAR CLUSTER M15. I. IDENTIFICATION, DISCOVERY, AND PERIOD DETERMINATION OF VARIABLE STARS

We present new BVI CCD photometry for variables in the globular cluster M15. Our photometry was obtained using both the image subtraction package ISIS and DAOPHOT/ALLFRAME. The data were acquired in 2001 on two observing runs on 11 observing nights using the 2 m telescope of the Bulgarian National Astronomical Observatory “Rozhen” with a Photometrics CCD camera. For 39 previously known variables, we present a period for the first time, and improved periods were obtained for many previously known variables. Fourteen new variables are reported. We present updated Bailey diagrams for the cluster, and discuss its Oosterhoff classification. Although many of M15's RRab pulsators fall at an intermediate locus between Oosterhoff types I and II (OoII) in the Bailey diagram, we argue that M15 is indeed a bona fide OoII globular cluster.
Laticifer growth pattern is guided by cytoskeleton organization

Laticifers are secretory structures that produce latex, forming a specialized defense system against herbivory. Studies using anatomical approaches to investigate laticifer growth patterns have described their origin; however, their mode of growth, i.e., whether growth is intrusive or diffuse, remains unclear. Studies investigating how cytoskeleton filaments may influence laticifer shape establishment and growth patterns are lacking. In this study, we combined microtubule immunostaining and developmental anatomy to investigate the growth patterns in different types of laticifers. Standard anatomical methods were used to study laticifer development. Microtubules were labelled through immunolocalization of α-tubulin in three types of laticifers from three different plant species: nonanastomosing (Urvillea ulmacea), anastomosing unbranched with partial degradation of terminal cell walls (Ipomoea nil), and anastomosing branched laticifers with early and complete degradation of terminal cell walls (Asclepias curassavica). In both nonanastomosing and anastomosing laticifers, as well as in differentiating meristematic cells, parenchyma cells and idioblasts, microtubules were perpendicularly aligned to the cell growth axis. The analyses of laticifer microtubule orientation revealed an arrangement that corresponds to those cells that grow diffusely within the plant body. Nonanastomosing and anastomosing laticifers, branched or not, have a pattern which indicates diffuse growth. This innovative study on secretory structures represents a major advance in the knowledge of laticifers and their growth mode.
Ionospheric Radio Propagation

From Preface: "The purpose of this book is to replace, in part, a previous publication of the National Bureau of Standards (Circular 462) with the same title. The scope of the present work has therefore been broadened to include aspects of ionospheric radio propagation which were not treated in earlier publication. "
ON THE ORIGIN OF THE SUB-JOVIAN DESERT IN THE ORBITAL-PERIOD–PLANETARY-MASS PLANE

Transit and radial velocity observations indicate a dearth of sub-Jupiter-mass planets on short-period orbits, outlined roughly by two oppositely sloped lines in the period–mass plane. We interpret this feature in terms of high-eccentricity migration of planets that arrive in the vicinity of the Roche limit, where their orbits are tidally circularized, long after the dispersal of their natal disk. We demonstrate that the two distinct segments of the boundary are a direct consequence of the different slopes of the empirical mass–radius relation for small and large planets, and show that this relation also fixes the mass coordinate of the intersection point. The period coordinate of this point, as well as the detailed shape of the lower boundary, can be reproduced with a plausible choice of a key parameter in the underlying migration model. The detailed shape of the upper boundary, on the other hand, is determined by the post-circularization tidal exchange of angular momentum with the star and can be reproduced with a stellar tidal quality factor Q * ′ ∼ 10 6 ? > .
KINEMATICS IN THE GALACTIC BULGE WITH APOGEE. II. HIGH-ORDER KINEMATIC MOMENTS AND COMPARISON TO EXTRAGALACTIC BAR DIAGNOSTICS

Much of the inner Milky Way’s (MW) global rotation and velocity dispersion patterns can be reproduced by models of secularly evolved, bar-dominated bulges. More sophisticated constraints, including the higher moments of the line-of-sight velocity distributions (LOSVDs) and limits on the chemodynamical substructure, are critical for interpreting observations of the unresolved inner regions of extragalactic systems and for placing the MW in context with other galaxies. Here, we use SDSS-APOGEE data to develop these constraints, by presenting the first maps of the skewness and kurtosis of the LOSVDs of metal-rich and metal-poor inner MW stars (divided at [Fe/H] = −0.4), and comparing the observed patterns to those that are seen both in N-body models and in extragalactic bars. Despite closely matching the mean velocity and dispersion, the models do not reproduce the observed skewness patterns of the LOSVDs in different ways, which demonstrates that our understanding of the detailed orbital structure of the inner MW remains an important regime for improvement. We find evidence in the MW of the skewness–velocity correlation that is used as a diagnostic of extragalactic bars/bulges. This correlation appears in metal-rich stars only, providing further evidence for different evolutionary histories of chemically differentiated populations. We connect these skewness measurements to previous work on high-velocity “peaks” in the inner Galaxy, confirming the presence of that phenomenon, and we quantify the cylindrical rotation of the inner Galaxy, finding that the latitude-independent rotation vanishes outside l ∼ 7°. Finally, we evaluate the MW data in the light of selected extragalactic bar diagnostics and discuss the progress and challenges in using the MW as a resolved analog of unresolved stellar populations.
Powerful Outflows and Feedback from Active Galactic Nuclei

Active Galactic Nuclei (AGN) represent the growth phases of the supermassive black holes in the center of almost every galaxy. Powerful, highly ionized winds, with velocities $\sim 0.1- 0.2c$ are a common feature in X--ray spectra of luminous AGN, offering a plausible physical origin for the well known connections between the hole and properties of its host. Observability constraints suggest that the winds must be episodic, and detectable only for a few percent of their lifetimes. The most powerful wind feedback, establishing the $M -\sigma$ relation, is probably not directly observable at all. The $M - \sigma$ relation signals a global change in the nature of AGN feedback. At black hole masses below $M-\sigma$ feedback is confined to the immediate vicinity of the hole. At the $M-\sigma$ mass it becomes much more energetic and widespread, and can drive away much of the bulge gas as a fast molecular outflow.
Setup and Operation of a Spectroscopic Imaging STM for the Study of Iron-Based Superconductors

Keywords: scanning tunneling microscopy ; spectroscopic imaging ; sapphire ; low temperature ; high magnetic field ; unconventional superconductivity ; iron-based superconductors These Ecole polytechnique federale de Lausanne EPFL, n° 5948 (2014)Programme doctoral PhysiqueFaculte des sciences de baseInstitut de physique de la matiere condenseeLaboratoire de science a l'echelle nanometriqueJury: Prof. N. Grandjean (president); Prof. K. Kern (directeur); Prof. F. Baumberger, Prof. D. Pavuna, Prof. W. Wulfhekel (rapporteurs) Public defense: 2014-2-12 Reference doi:10.5075/epfl-thesis-5948Print copy in library catalog Record created on 2014-02-05, modified on 2017-05-12
The astrochemical evolution of turbulent giant molecular clouds: physical processes and method of solution for hydrodynamic, embedded starless clouds

Contemporary galactic star formation occurs predominantly within gravitationally unstable, cold, dense molecular gas within supersonic, turbulent, magnetized giant molecular clouds (GMCs). Significantly, because the chemical evolution timescale and the turbulent eddy-turnover timescale are comparable at typical GMC conditions, molecules evolve via inherently non-equilibrium chemistry which is strongly coupled to the dynamical evolution of the cloud. Current numerical simulation techniques, which include at most three decades in length scale, can just begin to bridge the divide between the global dynamical time of supersonic turbulent GMCs, and the thermal and chemical evolution within the thin post-shock cooling layers of their background turbulence. We address this GMC astrochemical scales problem using a solution methodology, which permits both complex three-dimensional turbulent dynamics as well as accurate treatment of non-equilibrium post-shock thermodynamics and chemistry. We present the current methodology in the context of the larger scope of physical processes important in understanding the chemical evolution of GMCs, including gas-phase chemistry, dust grains and surface chemistry, and turbulent heating. We present results of a new Lagrangian verification test for supersonic turbulence. We characterize the evolution of these species according to the dimensionless local post-shock Damk\"{o}hler number, which quantifies the ratio of the dynamical time in the post-shock cooling flow to the chemical reaction time of a given species. Lastly, we discuss implications of this work to the selection of GMC molecular tracers, and the zeroing of chemical clocks of GMC cores.
The universal Hopf operads of the bar construction

The goal of this memoir is to prove that the bar complex B(A) of an E-infinity algebra A is equipped with the structure of a Hopf E-infinity algebra, functorially in A. We observe in addition that such a structure is homotopically unique provided that we consider unital operads which come equipped with a distinguished 0-ary operation that represents the natural unit of the bar complex. Our constructions rely on a Reedy model category for unital Hopf operads. For our purpose we define a unital Hopf endomorphism operad which operates functorially on the bar complex and which is universal with this property. Then we deduce our structure results from operadic lifting properties. To conclude this memoir we hint how to make our constructions effective and explicit.
Efficient time splitting schemes for the monodomain equation in cardiac electrophysiology

Approximating the fast dynamics of depolarization waves in the human heart described by the monodomain model is numerically challenging. Splitting methods for the PDE‐ODE coupling enable the computation with very fine space and time discretizations. Here, we compare different splitting approaches regarding convergence, accuracy, and efficiency. Simulations were performed for a benchmark problem with the Beeler–Reuter cell model on a truncated ellipsoid approximating the left ventricle including a localized stimulation. For this configuration, we provide a reference solution for the transmembrane potential. We found a semi‐implicit approach with state variable interpolation to be the most efficient scheme. The results are transferred to a more physiological setup using a bi‐ventricular domain with a complex external stimulation pattern to evaluate the accuracy of the activation time for different resolutions in space and time.
Integrative CUT&Tag/RNA-Seq analysis of histone variant macroH2A1-dependent orchestration of human iPSCs reprogramming

Human-induced pluripotent stem cells (iPSCs) can be derived from adult stem cells by forced expression of defined transcription factors. This paves the way for autologous iPSC-derived therapies, which, however, are not yet considered safe. Moreover, reprogramming of somatic cells into iPSCs is an inefficient process, in the range of 0.1%–1%. The epigenetic mechanisms implicated in iPSCs reprogramming are not well understood. The substitution of canonical histone H2A with macroH2A1 histone variant exon-spliced isoforms (macroH2A1.1 and macroH2A1.2) appears as an emerging regulator of iPSCs identity. In particular, we have previously shown that overexpression of macroH2A1.1 led to a more efficient iPSCs reprogramming, by not fully defined mechanisms. Cleavage under targets and tagmentation (CUT&Tag) is a recent methodology used for robust epigenomic profiling of a limited amount of cells. Here, we performed the first integrative CUT&Tag/RNA-Seq analysis of the histone variant macroH2A1-dependent orchestration of iPSCs reprogramming using human umbilical vein endothelial cells (HUVEC) during their reprogramming into iPSC over-expressing tagged macroH2A1.1 or macroH2A1.2. Our results demonstrate a higher and more widespread genome occupancy and a greater number of differentially expressed genes orchestrated by macroH2A1.1 in HUVEC undergoing reprogramming as compared to macroH2A1.2, which involved pervasive functions related to the three embryonic germ layers and increased overlap with CTCF, FOS, GATA2, and POLR2A transcription factor binding sites. In particular, all predicted macroH2A1.1 activating pathways were related to ectoderm/neural processes. As macroH2A1 isoforms have been previously associated with pathologies of the nervous system, our findings may provide relevant molecular insights for modeling neurodegenerative diseases using iPSCs.
Classical and Relativistic Conservation of Momentum Flux in Radio-Galaxies

A new set of laws of motion for turbulent jets propagating in an intergalactic medium characterized by a decreasing density is derived by applying conservation of momentum flux both in the classical and relativistic framework. Two characteristic features of radio-galaxies, such as oscillations and curvature, are modeled by a classical helicoidal jet. A third feature of a radio-galaxy, the appearance of knots, is explained as an effect due to the theory of images.
ON THE STELLAR POPULATIONS AND EVOLUTION OF STAR-FORMING GALAXIES AT 6.3 < z ⩽ 8.6

Observations of very distant galaxies probe both the formation and evolution of galaxies, and also the nature of the sources responsible for reionizing the intergalactic medium (IGM). Here, we study the physical characteristics of galaxies at 6.3 < z ⩽ 8.6, selected from deep near-infrared imaging with the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. We investigate the rest-frame ultraviolet (UV) colors, stellar masses, ages, metallicities, and dust extinction of this galaxy sample. Accounting for the photometric scatter using simulations, galaxies at z∼ 7 have bluer UV colors compared to typical local starburst galaxies at >4σ confidence. Although the blue colors of galaxies at these redshifts necessitate young ages (<100 Myr), low or zero dust attenuation, and low metallicities, these are explicable by normal (albeit unreddened) stellar populations, with no evidence for near-zero metallicities and/or top-heavy initial mass functions. Most of these galaxies are undetected in deep Spitzer Infrared Array Camera imaging. However, the age of the universe at these redshifts limits the amount of stellar mass in late-type populations, and the WFC3 photometry implies galaxy stellar masses ∼108–109 M☉ for Salpeter initial mass functions to a limiting magnitude of M1500 ∼ −18. The masses of “characteristic” (L*) z > 7 galaxies are smaller than those of L* Lyman break galaxies at lower redshifts, and are comparable to less evolved galaxies selected on the basis of their Lyα emission at 3 < z < 6, implying that the 6.3 < z ⩽ 8.6 galaxies are the progenitors of more evolved galaxies at lower redshifts. We estimate that Lyα emission is able to contribute to the observed WFC3 colors of galaxies at these redshifts, with an estimated typical line flux of ≈ 10−18 erg s−1 cm−2, roughly a factor of 4 below currently planned surveys. The integrated UV specific luminosity for the detected galaxies at z ∼ 7 and z ∼ 8 is within factors of a few of that required to reionize the IGM assuming low clumping factors, even with no correction for luminosity incompleteness. This implies that in order to reionize the universe, galaxies at these redshifts have a high (∼50%) escape fraction of Lyman continuum photons, possibly substantiated by the very blue colors of this population.
Recent Seasonal Spatiotemporal Variations in Alpine Glacier Surface Elevation in the Pamir

Climate change can lead to seasonal surface elevation variations in alpine glaciers. This study first uses DEM (Digital Elevation Model) of Pamir glaciers to develop a denoising model for laser altimetry of ICESat-2 footprints, which reduces the standard deviation of the differences between ICESat-2 footprints and corresponding datum DEM from 13.9 to 3.6 m. Second, the study constructs a calibration processing model for solving the problem that laser footprints obtained at different times have inconsistent plane positions. We calculates plane position and elevation differences between the two laser footprints in the local area of 0.05 × 0.05° from 2018 to 2021. The elevations constructed by laser footprints shows a strong correlation with the datum elevation over the different periods, and effectively preserve the time-series variation information of glacier surface elevation (GSE). Based on these two models, the spatiotemporal variations of the surface elevation of the Pamir glaciers is established as a function of seasons. There are three main conclusions: (1) The GSE in the Pamir increased slightly from 2018 to 2021 at an average rate of +0.02 ± 0.01 m/year. The time series with elevation increase was located exactly on the glacial ablation zone, and the time series with elevation decrease occurred on the glacial accumulation zone. Both observations demonstrate the surge state of the glacier. (2) The Pamir eastern (Zone I) and northwestern (Zone III) regions had large glacier accumulation areas. GSE in these two regions has increased in recent years at yearly rates of +0.25 ± 0.13 and +0.06 ± 0.04 m/year, respectively. In contrast, the GSE of small glaciers in Zones II and IV has decreased at a yearly rate of −0.96 ± 0.37 and −0.24 ± 0.18 m/year, respectively. Climate was the primary factor influencing the increase in GSE in Zones I and III. The westerly circulation had been reinforced in recent years, and precipitation had increased dramatically at a rate of +0.99 mm/year in the northwestern section of the Pamir; this was the primary cause of the increase in GSE. (3) The increased precipitation and decreased temperature were both important factors causing an overall +0.02 ± 0.01 m/year variation of GSE in this region. The GSE in the four sub-regions showed different variation trends because of variations in temperature and precipitation. The external causes that affected the increase in GSE in the region included an average yearly temperature decrease at the rate of 0.54 ± 0.36 °C/year and a total yearly precipitation increase of 0.46 ± 0.29 mm/year in the study area from 2018 to 2021.
Collective Coordinates in One-Dimensional Soliton Models Revisited

We compare numerical solutions to the full field equations to simplified approaches based on implementing three collective coordinates for kink-antikink interactions within the $\varphi^4$ and $\phi^6$ models in one time and one space dimensions. We particularly pursue the question whether the collective coordinate approximation substantiates the conjecture that vibrational modes are important for resonance structures to occur in kink-antikink scattering.
InvBERT: Reconstructing Text from Contextualized Word Embeddings by inverting the BERT pipeline

Digital Humanities and Computational Literary Studies apply text mining methods to investigate literature. Such automated approaches enable quantitative studies on large corpora which would not be feasible by manual inspection alone. However, due to copyright restrictions, the availability of relevant digitized literary works is limited. Derived Text Formats (DTFs) have been proposed as a solution. Here, textual materials are transformed in such a way that copyright-critical features are removed, but that the use of certain analytical methods remains possible. Contextualized word embeddings produced by transformer-encoders (like BERT) are promising candidates for DTFs because they allow for state-of-the-art performance on various analytical tasks and, at first sight, do not disclose the original text. However, in this paper we demonstrate that under certain conditions the reconstruction of the original copyrighted text becomes feasible and its publication in the form of contextualized token representations is not safe. Our attempts to invert BERT suggest, that publishing the encoder as a black box together with the contextualized embeddings is critical, since it allows to generate data to train a decoder with a reconstruction accuracy sufficient to violate copyright laws.