bluuebunny/crossref_metadata_2025 huggingface dataset:
The spin rate properties of Galactic massive O-type stars
Authors: Holgado G. , Simón-Díaz S. , Herrero A. , Barbá R. H.
Published: August 2024

We present results from a recent study of the spin rate properties of a sample of more than 400 Galactic O-type stars surveyed by the IACOB and OWN projects. We combine vsini, Teff, and logg estimates with information about the spectroscopic binarity status for 285 of the stars in the sample, and provide a renewed overview about how the empirical distribution of projected rotational velocities in the O-star domain depends on mass, evolutionary and binary status. The obtained distributions are then compared with predictions of state-of-the-art population synthesis simulations including binary interaction, and used to provide hints about the initial velocity distribution of stars with masses in the range 15-80 M⊙.
Multiplicity of Northern bright O-type stars with optical long baseline interferometry. Results of the pilot survey
Authors: Lanthermann Cyprien
Published: August 2024

The study of the multiplicity of massive stars gives hints of their formation processes and their evolution path. Optical interferometry is mandatory to fulfill our knowledge of their multiplicity by probing the separation gap between 1 and 50 mas. We demonstrated the capability of the new interferometric instrument MIRC-X, located at the CHARA array, to study a large sample of more than 120 (H < 7.5) O-type stars. We observed 29 O-type star systems, including a couple of systems in average atmospheric conditions around a magnitude of H = 7.5. Out of these 29 systems, we detected 18 companions in 16 different systems, resulting in a multiplicity fraction fm = 16/29 = 0.55, and a companion fraction of fc = 18/29 = 0.62. We observed for the first time 11 of these detected companions. This study concludes that a large survey on more than 120 Northern O-type stars is possible with MIRC-X.
Asteroseismology reveals the near-core magnetic field strength in the early-B star HD 43317
Authors: Bowman D. M. , Lecoanet D. , Van Reeth T.
Published: August 2024

Spectropolarimetic campaigns have established that large-scale magnetic fields are present at the surfaces of approximately 10% of massive dwarf stars. However, there is a dearth of magnetic field measurements for their deep interiors. Asteroseismology of gravity-mode pulsations combined with rotating magneto-hydrodynamical calculations of the early-B main-sequence star HD 43317 constrain its magnetic field strength to be approximately 5 × 105 G just outside its convective core. This proof-of-concept study for magneto-asteroseismology opens a new window into the observational characterisation of magnetic fields inside massive stars.
X-ray emission characteristics of an O+O binary HD 93205
Authors: Arora Bharti , Pandey Jeewan C.
Published: August 2024

A detailed X-ray study of a massive binary called HD 93205 has been made using long-term XMM-Newton observations. The X-ray spectrum of HD 93205 displays negligible counts above 5 keV. The two thermal plasma emission models with average temperature values as ∼ 0.20 and ∼ 0.60 keV are required to explain the X-ray spectra. The X-ray flux variations in the binary are noticed to be in qualitative agreement with the wind-wind collision model but with a few deviations from the expected 1/D trend (D is the binary separation).
Constraining the behaviour of the young massive stars through interferometry
Authors: Bordier Emma , Frost Abigail J. , Sana Hugues , Mérand Antoine
Published: August 2024

The formation of multiples has seen some significant progress over the past years mainly due to the advent and the expansion of high-angular resolution facilities. Star-forming regions are the laboratories where massive stars can be caught right after their formation phase. Still, the observational constraints and the properties of young multiple systems are poorly documented. These proceedings contain recent results about the multiplicity properties of six young O-type stars in the M17 star-forming region, observed by the means of near-IR interferometric observations, which have provided insight into the origin of massive close binaries in a cluster environment.
Obliquely Rotating Massive Star Magnetospheres
Authors: ud-Doula Asif , Owocki Stanley P.
Published: August 2024

We present results from 3D MHD simulations of the magnetospheres from massive stars with a dipole magnetic axis that has an arbitrary obliquity angle (β) to the stars rotation axis. As an initial direct application, we examine the global structure of co-rotating disks for tilt angles β=0, 45 and 90 degrees using ζ Pup stellar parameters as a prototype. We find that for models with rapid stellar rotation (∼ 0.5 critical rotation), accumulation surfaces closely resemble the form predicted by the analytic Rigidly Rotating Magnetosphere (RRM) model, but with a mass distribution and outer disk termination set by centrifugal breakout processes. However, some significant differences are found including warping resulting from the dynamic nature of the MHD models in contrast to static RRM models. These MHD models can be used to synthesize rotational modulation of photometric absorption and H-alpha emission for a direct comparison with observations.
Next generation spectroscopic analysis for large samples of massive stars
Authors: Bestenlehner Joachim M.
Published: August 2024

Upcoming large-scale spectroscopic surveys such as WEAVE and 4MOST will provide thousands of spectra of massive stars, which need to be analysed in an efficient and homogeneous way. Studies on massive stars are usually based on samples of a few hundred objects which pushes current spectroscopic analysis tools to their limits because visual inspection is necessary to verify the spectroscopic fit.

The novel spectroscopic analysis pipeline takes advantage of the statistics that large samples provide, and determines the model error to account for imperfections in stellar atmosphere codes due to simplified, wrong or missing physics. Considering observational plus model uncertainties improve spectroscopic fits. The pipeline utilises the entire spectrum rather than selected diagnostic lines allowing a wider range of temperature from B to early O stars to be analysed. A small fraction of stars like peculiar, contaminated or spectroscopic binaries require visual inspection, which are identified through their larger uncertainties.
The Diversity of Massive Stellar Transients Found in Sky-surveys
Authors: Lyman Joe
Published: August 2024

The recent generation of dedicated wide-field, high-cadence sky-surveys have overwhelmed discovery statistics for all manner of extra-galactic transients, and uncovered new phenomena seemingly linked to the demise of massive stars. For the more established classes of transients, such as core-collapse supernovae, surges in discoveries are allowing true population studies to provide quantitative constraints not only on the explosion properties, but also on the progenitor populations. Crucially, such population insights are benefiting from creation of samples of transients constructed with largely unbiased methods for discovery and characterisation. Surrounding these discoveries are increasing samples of extreme transients that do not fit the standard core-collapse paradigm - requiring the invocation of exotic progenitor stars and placing demands on the stellar evolution of such systems. Here I will provide a high-level observationally-driven overview of recent results related to massive stellar transients.
Multiplicity of Galactic Luminous Blue Variable stars
Authors: Mahy Laurent , Lanthermann Cyprien , Gosset Eric , Hutsemékers Damien , Kluska Jacques , Lobel Alex , Reggiani Maddalena , Sana Hugues
Published: August 2024

Luminous Blue Variable stars (LBVs) are rare and enigmatic. Often cited as evolutionary stages in the single-star evolution, the idea that binary evolution produces the LBV state was already considered, 30 years ago.

It is now commonly accepted that a significant part of massive stars are born in multiple systems. One aspect that also emerged is that massive stars have on average at least two companions, i.e. they are triples. This immediately implies that a number of LBVs should have evolved as part of multiple systems.

While some LBVs are confirmed as binaries, different methods were used to derive their multiplicity, with different results. We report on a systematic search for multiplicity using spectroscopy, interferometry in a sample of 20 LBVs. Spectroscopy provides us with a bias-corrected binary fraction of

$\[62_{ - 24}^{ + 38}\]$

%, and a percentage of 50–70% is found from interferometry. This has a high impact on the way that these objects might be formed.
Two-dimensional models of fast rotating stars and mixing processes
Authors: Rieutord Michel , Gagnier Damien
Published: August 2024

In this short review we present the recent progresses in modelling fast rotating stars in two dimensions. We thus give a brief description of the features of the public domain code ESTER that can compute self-consistently the structure and the large-scale flows (differential rotation and meridional circulation) of an axisymmetric stellar model of a (fast) rotating early-type main sequence star. We illustrate these modelling with the recent results obtained on Altair, a nearby extremely fast rotator. We then discuss the various way mixing takes place in the stably stratified radiative envelope of early-type stars, and especially in massive ones where the radiative winds add a new source of large-scale flows, which are shown to be strongly anisotropic and very difficult to represent in one dimension.
The origin of massive stellar systems via disk fragmentation
Authors: Oliva G. André , Kuiper Rolf
Published: August 2024

In this contribution, we explore the question on the formation of multiple massive stellar systems via disk fragmentation with the help of the highest-resolution simulations to date of a fragmenting disk in the context of massive star formation. The simulations start from a collapsing cloud of 200 solar masses, followed by the formation of an accretion disk that develops spiral arms and fragments. Due to the high resolution of our grid, we are able to self-consistently form the fragments without the need for a subgrid module such as sink particles. We track the formed fragments into the first stages of companion formation, which allows us to give an estimate of the multiplicity of the final system due to disk fragmentation. We find in total around ∼6 fragments, some at orbits of ∼ 1000 au, and some close (possibly spectroscopic) companions.
Constraints on the stellar upper mass limit from simulations of UV disk ablation
Authors: Kee N. Dylan , Kuiper Rolf
Published: August 2024

This contribution presents recent advances in identifying the stellar upper mass limit using simulations of UV radiative feedback during the star formation process. Generally, due to computational costs and a focus on au to parsec scales, simulations of massive star formation do not trace the flow of material to distances closer than a few au from the forming star. However, UV line-acceleration acts directly on accreting material in the sub-au circumstellar region, thereby efficiently ablating the surface layers off the protostellar disk. For stars on the order of a few hundred solar masses, this disk destruction rate exceeds the accretion rate, destroying the disk faster than it is replenished, and setting a maximum stellar mass as a function of metallicity that can be attained by single star formation channels.
Metallicity distributions of core-collapse supernovae within 30Mpc: Evidence for a lack of single massive Ib progenitors at low metallicities.
Authors: Pledger Joanne L. , Ganss Rudi , Sansom Anne E. , James Philip A. , Puls Joachim , Habergham-Mawson Stacey M.
Published: August 2024

Local HII environment metallicities of 65 supernovae (SNe), obtained with INT/IDS, have been determined using the N2 and O3N2 strong emission line methods. Resulting cumulative distribution functions reveal a narrower distribution for Ib SNe (standard deviation σ ∼ 0.06 dex) compared to Ic and IIP distributions (σ ∼ 0.15 dex). This narrow distribution of Ib SNe is confirmed with an extended dataset using data from Galbany et al. (2018). Statistical tests confirm a statistically significant difference between the Ib and II-P metallicity distributions with < 5% probability that they result from the same progenitors. This narrow distribution suggests a lack of Type Ib SNe in low metallicity environments and points towards single star progenitors for these Type Ib SNe, rather than binaries. It also suggests that single massive stars at low metallicity are not commonly able to produce helium-rich Type Ib supernovae.
Constraining physical processes in pre-supernovae massive star evolution
Authors: Higgins Erin R. , Vink Jorick S. , Sander Andreas , Hirschi Raphael
Published: August 2024

While we have growing numbers of massive star observations, it remains unclear how efficient the key physical processes such as mass loss, convection and rotation are, or indeed how they impact each other. We reconcile this with detailed stellar evolution models, yet these models have their own drawbacks with necessary assumptions for 3-dimensional processes like rotation which need to be adapted into 1-dimensional models. The implementation of empirical mass-loss prescriptions in stellar evolution codes can lead to the extrapolation of base rates to unconstrained evolutionary stages leading to a range of uncertain fates. In short, there remain many free parameters and physical processes which need to be calibrated in order to align our theory better with upcoming observations. We have tested various processes such as mass loss and internal mixing, including rotational mixing and convective overshooting, against multiple observational constraints such as using eclipsing binaries, the Humphreys-Davidson limit, and the final masses of Wolf-Rayet stars, across a range of metallicities. In fact, we developed a method of disentangling the effects of mixing and mass loss in the ‘Mass-Luminosity Plane’ allowing direct calibration of these processes. In all cases, it is important to note that a combined appreciation for both stellar winds and internal mixing are important to reproduce observations.
Infrared studies of the massive stellar population at the Galactic Center and the inner disk
Authors: Najarro Francisco , Clark J. S. , Lohr Marcus , Patrick Lee R. , García Miriam , Castellanos Raúl , Muñoz-Sánchez Gonzalo , de la Fuente Diego
Published: August 2024

We present results from our ongoing infrared spectroscopic studies of the massive stellar content at the Center of the Milky Way (GC) and across the obscured Galactic disk. Together with the full characterization of these clusters, we seek to obtain a present day metallicity 2-D map of the inner Galaxy and characterize the influence on the bar in the chemical evolution. We will also constrain the clusters IMFs, infer the presence of possible top-heavy recent star formation histories and test massive star formation channels: clusters vs isolation.
Hunting for red supergiant binaries: UVIT photometry of the SMC
Authors: Patrick Lee R. , Thilker David , Lennon Danny , Bianchi Luciana , Schootemeijer Abel , Dorda Ricardo , Langer Norbert , Negueruela Ignacio
Published: August 2024

. We present UVIT/Astrosat UV photometry of the RSG population of the Small Cloud galaxy (SMC). As RSGs are extremely faint in the far-UV, these observations directly probe potential companion stars. From a sample of 861 SMC RSGs, we find 88 have detections at far-UV wavelengths: a clear signature of binarity. Stellar parameters are determined for both components, which allows us to study - for the first time - the mass-ratio (q) distribution of RSG binary systems. We find a flat mass-ratio distribution best describes the observations up to MRSG ∼15M⊙. We account for our main observing bias (i.e. the limiting magnitude of the UVIT survey) to determine the intrinsic RSG binary fraction of 18.8 ± 1.5 %, for mass-ratios in the range 0.3.<q<1.0 and orbital periods approximately in the range 3<log P[days]<8.
Observations of Very Low-Metallicity Massive Stars
Authors: Garcia Miriam
Published: August 2024

Very metal-poor massive stars hold the key to interpret high-redshift star-forming galaxies and the early reionization epoch, but also contemporary events such as gravitational waves. To study these objects in resolved environments, we need to resort to dwarf irregular galaxies far from the potential wells of M31 and the Milky Way, and therefore distant. While the archives, recently boosted by the ULLYSES and XSHOOTU programs, store a healthy dataset of massive stars in the Milky Way and the Magellanic Clouds, the number of observed targets with poorer metal content than the SMC (1/5 Zȯ) is dramatically small. This paper reviews the state of observations of very metal-poor massive stars, assessing what can be realistically learned about their physics and evolution with current instrumentation, and arguing whether or not near-future facilities can remedy the gaps in the knowledge that remain.
Stability analysis of radial oscillation modes in massive stars
Authors: Sánchez Arias J. P. , Guha S. , Kraus M.
Published: August 2024

During the evolution of massive stars, their properties change significantly. But stellar parameters of massive stars have the biggest uncertainties in stellar astrophysics, specifically in the post-main sequence stages where blue supergiant stars are located. These stars experience mass loss events during their evolution which are supposed to be related to strange-modes instabilities. In this work, we explore the stability of oscillation modes in massive stars for different masses, and a range of mass-loss rates, with the aim to provide clues about the connection between strange modes instabilities and mass-loss events.
Polstar : a FUV Spectropolarimetry Mission
Authors: St-Louis Nicole ,   the Polstar consortium
Published: August 2024

In this paper, we give a brief description of the Polstar instrument, an ultraviolet (UV) spectropolarimetric, Midex-class mission proposed to NASA to study the winds of massive stars as well as interstellar medium and protoplanetary discs topics.
Exploring a direct observational method to measure high-redshift cloud collapse timescales and GRB progenitor lifetimes
Authors: Cooke Jeff , Khetan Nandita , Savaglio Sandra , Zhang Jielai , Suhr Mark
Published: August 2024

Long gamma-ray bursts (LGRBs) and superluminous supernovae (SLSNe) are expected to result from massive star deaths. However to date, there has been no direct observational measurement of their cloud collapse timescales nor progenitor lifetimes to help constrain their mass. Our analyses of z 2 LGRB afterglow spectra and Hubble Space Telescope images find a higher fraction of host galaxies that are interacting, have a close companion, and/or may have experienced a recent galaxy ‘fly by’ as compared to the general z 2 galaxy population. A smaller set of z 2 SLSNe suggests a similar result. Under the hypothesis that galaxy interactions induce cloud collapse and star formation near their closest approach, we explore measurements of the host and companion galaxy velocities and separations at the time of the LRGB/SLSN event as a direct physical means to measure the timescale of cloud collapse plus progenitor star lifetime.
Evolution and final fate of massive post-common-envelope binaries
Authors: Wei Dandan , Schneider Fabian R. N. , Podsiadlowski Philipp , Laplace Eva , Henneco Jan , Röpke Friedrich K. , Vetter Marco
Published: August 2024

Mergers of neutron stars and black holes are nowadays observed routinely thanks to gravitational-wave astronomy. In the isolated, binary-evolution channel, a common-envelope phase of a red supergiant and a compact object is crucial to sufficiently shrink the orbit and thereby enable a merger via gravitational-wave emission. Here, we use the outcome of three-dimensional hydrodynamic common-envelope simulations of a 9.4 solar mass red supergiant and a 5 solar mass black-hole to explore the further evolution and final fate of the remnant binary. The binary system undergoes another phase of mass transfer during which it is visible as an X-ray binary. We find that the donor star does not explode as an ultra-stripped supernova because of the large remaining envelope mass, but as a Type Ib/c supernova. Supernova kicks are actually required to sufficiently perturb the orbit and thus facilitate a merger within a Hubble time via gravitational-wave emission.
New empirical mass-loss rates and clumping properties of massive stars
Authors: Hawcroft Calum , Sana Hugues , Mahy Laurent , Sundqvist J. O. , Abdul-Masih M. , Bouret J. C. , Brands S. A. , de Koter A. , Driessen F. A. , Puls J.
Published: August 2024

Hot, massive stars are known to host unstable, radiation-driven outflowing winds, giving rise to dense clumps of material which severely affect the diagnostic techniques used to derive wind properties of massive stars. Most of the current diagnostic models account for wind inhomogeneities by assuming a one-component medium consisting of optically thin clumps, and maintaining a smooth velocity-field. However, this neglects important light-leakage effects through porous channels in-between the clumps. These light-leakage effects have recently been incorporated in the stellar atmosphere modelling code FASTWIND, and here we will present quantitative mass-loss results from a combined Ultraviolet-Optical wind analysis of O-supergiants in the Galaxy. Using a genetic-algorithm fitting-approach, we systematically investigate the impact the wind physics has on derived stellar and wind parameters, and how this depends on metallicity and spectral type. We compare our findings with earlier results (which do not take into account such light-leakage effects), to standard mass-loss rates usually included in evolution model studies of massive stars, and with theoretical predictions of clumping properties. We will also present the first systematic empirical constraints on the new wind parameters, associated with light-leakage, and compare these with theoretical predictions.
Properties of Primitive Galaxies
Authors: Heap Sara R. , Hubeny I. , Bouret J.-C. , Lanz T. , Brinchmann J.
Published: August 2024

We report on a study of 9 nearby primitive galaxies observed by Hubble’s COS far-UV spectrograph that can serve as templates of high-z galaxies to be observed by JWST. By “primitive galaxies,” we mean galaxies having a low stellar mass, and low gas metallicity, , whether they are local or at high redshift. We find that far-UV spectra of these galaxies show evidence of hard radiation, including X-rays. Following Thuan et al. (2004), we identify these galaxies as massive X-ray binaries containing a massive accreting stellar black hole. We further find that the lower the metallicity, the higher the probability of extremely strong X-radiation. Following Heger et al. (2003), we suggest that the accreting black hold is produced by direct collapse of stars having initial masses greater than 50 . The X-radiation produced by black hole disk directly affects the surrounding interstellar medium, and many of these effects are observable in far-UV spectra.
Fundamental parameters for 222 B-type stars for the X-shooter Spectral Library
Authors: Larkin C. J. K. , Verro Kristiina , Gonneau Anaïs , Trager S. C.
Published: August 2024

We use the MIDE3700 code to find effective temperatures (Teff) and surface gravities (log g) via the Barbier Chalonge Divan (BCD) method for 222 B-type stars in the ESO archive in preparation for their inclusion as an extension to the X-shooter Spectral Library (XSL). We find agreement of Δ log Teff ∼0.1σ and Δ log g ∼0.25σ of our results with a sample of literature stars. We populate a previously bare region of the XSL Kiel diagram in the ranges 9000 ≤ Teff ≤ 23000 K and 2.8 ≤ log g ≤ 4.0 dex, and thereby extend the lower age limit of XSL stellar population models by up to a factor ∼10 at [Fe/H] = −1.2 dex, and by a factor ∼2 at Solar metallicity.
Upper Mass-Loss Limits and Clumping in the Intermediate and Outer Wind Regions of OB stars
Authors: Rubio-Díez M. M. , Sundqvist J. O. , Najarro F. , Traficante A. , Puls J. , Calzoletti L. , Figer D.
Published: August 2024

Mass-loss is a key parameter throughout the evolution of massive stars. In this work we probe the radial clumping stratification of OB stars in the intermediate and outer wind regions (r ≳ 2R*; r, radial distance to photosphere), derive upper limits for mass-loss rates, Ṁmax, and compare them to current theoretical mass-loss recipes implemented in evolutionary models. A key conclusion of our analysis regards the derived upper-limit mass-loss rates of B supergiants, independently of clumping, which calls for an urgent revision of the role recombination of iron-like elements plays in determining the mass-loss rates of objects that cross the bi-stability region, and a careful analysis of corresponding effects for stellar evolution models.
A comprehensive empirical investigation of Galactic fast-rotating O-type stars
Authors: Britavskiy N. , Holgado G. , Simón-Díaz S. , Maíz Apellániz J. , Pantaleoni González M. , Nazé Y. , Burssens S. , Eldridge J. J.
Published: August 2024

Rotation is one of the important parameters affecting the evolution and final fate of massive stars but the origin of fast rotators remains unclear (imprint of the star formation process, result of binary interactions). In this work, we aim at investigating the binary status, photometric variability, and runaway status of a statistically meaningful sample of Galactic fast-rotating O stars. We perform a comprehensive multi-epoch analysis of new high-quality spectroscopic observations gathered by the IACOB and OWN surveys. Notably, we find that the total percentage of spectroscopic binaries in the investigated sample range between 25 and 40%, in agreement with previous finding for the case of O-type stars with lower projected rotational velocities. On the contrary, the fraction of runaway stars among fast rotators (∼35–50%) is significantly higher than in the case of slow rotators (∼20–30%). By combining all these observational results we will evaluate each scenario about the origin of fast rotators.
Astro+: Design, construction, and scientific exploitation of a large-scale massive star spectroscopic database
Authors: Rübke Klaus , Marco Amparo , Negueruela Ignacio , Herrero Artemio , Simon-Diaz Sergio , Tabernero Hugo , Patrick Lee
Published: August 2024

Massive stars are the objects that condition the evolution of the interstellar medium by the amount of energy released during their lives and especially by their death as a supernova explosion. All the data provided by the previous and ongoing missions of ground and space telescopes have saturated us with the amount of information, which is no longer easy to process daily by human routines. To this end, we present the development of a massive star spectroscopic interactive database designed for scientific research.
Stellar Structure and Evolution of Massive Rotating Single Stars
Authors: Hirschi R. , Kaiser E. , Eggenberger P. , Ekström S. , Georgy C. , Maeder A. , Meynet G.
Published: August 2024

Rotation plays an important role in the structure and evolution of massive stars. It leads to deviation from spherical symmetry for very fast rotating stars, mixing in otherwise unmixed radiative regions and generally increased mass loss. In addition, magnetic fields interact with rotation and lead to significant transport of angular momentum. In this article, we review the various rotational and magnetic instabilities present in massive stars and their implementation in one-dimensional stellar evolution codes. We then focus on their impact on the evolution of single rotating stars. Finally, we compare rotating models to observations and discuss ways to disentangle between various uncertainties.
Massive Stars in Low-metallicity Galaxies in the CLASSY Survey
Authors: Berg Danielle A. , James Beth L. , King Teagan , McDonald Meaghan , Chen Zuyi , Chisholm John , Heckman Timothy , Martin Crystal L. , Stark Dan P. ,   The CLASSY Team
Published: August 2024

Rest-frame far-ultraviolet spectra are fundamental to our understanding of star-forming galaxies, providing a unique window on massive star populations (MSs), chemical evolution, feedback processes, and reionization. JWST is ushering in a new era, pushing the FUV frontier beyond z=10. The success of such endeavors hinges on a comprehensive understanding of the MSs and gas conditions that power the observed spectra. The COS Legacy Archive Spectroscopic SurveY (CLASSY) is a powerful and promising solution providing high-quality, high-resolution FUV spectra of 45 nearby star-forming galaxies. The spectra contain a suite of features that simultaneously characterize the MSs that populate metal-poor galaxies, physical properties of large-scale outflows, and chemical abundance patterns. The CLASSY sample is consistent with the z 0 mass-metallicity relationship and spans 1.5 dex in metallicity. These unique properties make CLASSY the benchmark training set for studies of MSs in star-forming galaxies both across cosmic time and connecting metal-poor to metal-rich populations.
CMD for atmospheres of massive stars created by using CMFGEN synthetic spectra
Authors: Arrieta Anabel , Payen-Sandoval Agustín , Arias Lorena , Zsargo Janos , Fierro-Santillán Celia , Klapp Jaime
Published: August 2024

We present Color Magnitude Diagrams (CMDs) created by using our database of 43,340 synthetic CMFGEN spectra. For each calculated spectra we measure the absolute flux by Johnson and Gaia photometry filters and build synthetic CMDs.
Digitale Fort- und Weiterbildung in der Pflege
Authors: Quernheim German
Published: August 2024

Zusammenfassung: Digitales Lernen hat sich in den letzten Jahren kreativ weiterentwickelt. Vergessen Sie bisherige Erfahrungen von E-Learnings – in den letzten vier Jahren gab es massive kreative Weiterentwicklungen der Tools, die hier im Beitrag vorgestellt werden. Damit werden digitale Lernformate spannend, fordernd, lustvoll, abwechslungsreich und ermöglichen Konnektivismus.
Integration of DDPM and ILUES for Simultaneous Identification of Contaminant Source Parameters and Non‐Gaussian Channelized Hydraulic Conductivity Field
Authors: Zhang Xun , Jiang Simin , Zheng Na , Xia Xuemin , Li Zhi , Zhang Ruicheng , Zhang Jiangjiang , Wang Xinshu
Published: August 2024

Identifying highly channelized hydraulic conductivity fields and contaminant source parameters remains a challenging task, primarily due to the non‐Gaussian nature and high dimensionality of the parameter space, as well as the computational burden caused by repeatedly running forward numerical models. This study proposes a novel deep learning parameterization method called AEdiffusion, which combines Diffusion Denoising Probabilistic Model (DDPM) with Variational Autoencoder (VAE) for dimensionality reduction. The method employs a generator‐refiner strategy to generate high‐dimensional aquifer properties from low‐dimensional latent representations. The inversion modeling was performed on a synthetic non‐Gaussian hydraulic conductivity field with line‐source contamination using the Iterative Local Updating Ensemble Smoother (ILUES) algorithm. The results demonstrate that the AEdiffusion‐ILUES framework can accurately identify model parameters. To reduce the computational burden, an AR‐Net‐WL (ARNW) surrogate model was introduced, resulting in an efficient inversion framework (AEdiffusion‐ILUES‐ARNW) with similar prediction accuracy and predictive uncertainty estimation as the AEdiffusion‐ILUES but at a lower computational cost.
Evaluation of Modeled Diurnal Warming Estimates for Application to Producing Sea Surface Temperature Analyses
Authors: Wick Gary A. , Castro Sandra L. , Harris Andrew , Mittaz Jonathan
Published: August 2024

Accurate knowledge of the amount of diurnal warming present in sea surface temperature (SST) observations at different times and effective depths is important for multiple applications including the production of blended SST analyses. This work explores the ability of a modified Kantha‐Clayson‐type one‐dimensional mixed layer ocean model with wave effects to accurately simulate the observed diurnal warming amplitude over a global grid when forced with coarse resolution numerical weather prediction (NWP) outputs. The sensitivity of the modeled diurnal amplitudes to multiple adjustable parameters and model configurations is evaluated to determine whether a preferred configuration can be identified that yields reliable predictions. The accuracy of the predictions is determined through comparison against estimates from operational SST retrievals from geostationary satellites. The results show that a single configuration can yield predictions that reproduce the observed range of diurnal warming amplitudes across a range of seasons and locations and an accurate occurrence frequency of the largest amplitude events. Simulated amplitudes fall along the one‐to‐one line with observations but with significant scatter due to factors including positioning of the NWP fluxes. The identified configuration is also shown to favorably reproduce diurnal warming observations from multiple research cruises. Overall uncertainty of the simulated diurnal warming amplitude across the different tests ranges between 0.4 K for all observations to ∼1 K for the largest warming events. While the focus is not on model comparisons, the results show improved performance relative to other models. Use of the model appears warranted but the associated uncertainty must be considered.
Nanomedicine-induced programmed cell death in cancer therapy: mechanisms and perspectives
Authors: Luobin Lin , Wanxin He , Yingxin Guo , Qinzhou Zheng , Zefeng Liang , Danyang Wu , Huaqin Li
Published: August 2024

The balance of programmed cell death (PCD) mechanisms, including apoptosis, autophagy, necroptosis and others, is pivotal in cancer progression and treatment. Dysregulation of these pathways results in uncontrolled cell growth and resistance to conventional therapies. Nanomedicine offers a promising solution in oncology through targeted drug delivery enabling precise targeting of cancer cells while preserving healthy tissues. This approach reduces the side effects of traditional chemotherapy and enhances treatment efficacy by engaging PCD pathways. We details each PCD pathway, their mechanisms, and innovative nanomedicine strategies to activate these pathways, thereby enhancing therapeutic specificity and minimizing harm to healthy tissues. The precision of nanotechnology in targeting PCD pathways promises significant improvements in cancer treatment outcomes. This synergy between nanotechnology and targeted PCD activation could lead to more effective and less toxic cancer therapies, heralding a new era in cancer treatment.
GRK2-mediated AKT activation controls cell cycle progression and G2 checkpoint in a p53-dependent manner
Authors: Rivas Verónica , González-Muñoz Teresa , Albitre Ángela , Lafarga Vanesa , Delgado-Arévalo Cristina , Mayor Federico , Penela Petronila
Published: August 2024

Cell cycle checkpoints, activated by stressful events, halt the cell cycle progression, and prevent the transmission of damaged DNA. These checkpoints prompt cell repair but also trigger cell death if damage persists. Decision-making between these responses is multifactorial and context-dependent, with the tumor suppressor p53 playing a central role. In many tumor cells, p53 alterations lead to G1/S checkpoint loss and the weakening of the G2 checkpoint, rendering cell viability dependent on the strength of the latter through mechanisms not fully characterized. Cells with a strong pro-survival drive can evade cell death despite substantial DNA lesions. Deciphering the integration of survival pathways with p53-dependent and -independent mechanisms governing the G2/M transition is crucial for understanding G2 arrest functionality and predicting tumor cell response to chemotherapy. The serine/threonine kinase GRK2 emerges as a signaling node in cell cycle modulation. In cycling cells, but not in G2 checkpoint-arrested cells, GRK2 protein levels decline during G2/M transition through a process triggered by CDK2-dependent phosphorylation of GRK2 at the S670 residue and Mdm2 ubiquitination. We report now that this downmodulation in G2 prevents the unscheduled activation of the PI3K/AKT pathway, allowing cells to progress into mitosis. Conversely, higher GRK2 levels lead to tyrosine phosphorylation by the kinase c-Abl, promoting the direct association of GRK2 with the p85 regulatory subunit of PI3K and AKT activation in a GRK2 catalytic-independent manner. Hyperactivation of AKT is conditioned by p53’s scaffolding function, triggering FOXO3a phosphorylation, impaired Cyclin B1 accumulation, and CDK1 activation, causing a G2/M transition delay. Upon G2 checkpoint activation, GRK2 potentiates early arrest independently of p53 through AKT activation. However, its ability to overcome the G2 checkpoint in viable conditions depends on p53. Our results suggest that integrating the GRK2/PI3K/AKT axis with non-canonical functions of p53 might confer a survival advantage to tumor cells.
Perspective: Clinical care of pedophilic individuals in Zurich, Switzerland
Authors: de Tribolet-Hardy Fanny , Veitz Simon , Dittli Laura , Habermeyer Elmar
Published: August 2024

Individuals with pedophilia are considered to have an elevated risk for child sexual abuse (CSA). Nevertheless, it is assumed that pedophilic sexual impulses can be controlled from acting out. To prevent CSA an outpatient treatment facility for people with pedophilia was founded in Zurich, Switzerland in 2021. The program focuses on the prevention of CSA and improvement of quality of life, incorporating empirically validated treatment principles, such as the Risk-Need-Responsivity (RNR) model and the Good Lives Model (GLM). Within the initial 24-month 142 individuals sought help, 46 individuals (mean age 36.0 ± 12.4 years) completed the assessment phase, two-thirds suffered from psychiatric comorbidities, and 67.4% reported sexual delinquency. The high drop-out rate was predominantly due to ongoing criminal proceedings, or other mental health conditions. Overall patients at this facility generally sought treatment voluntarily, leading to good treatment adherence, with severe self-harm being more prevalent than acute danger to others. A treatment approach focused solely on pedophilia is considered insufficient; psychiatric and psychosocial factors must also be addressed.
Optimising CNT-FET biosensor design through modelling of biomolecular electrostatic gating and its application to β-lactamase detection
Authors: Gwyther Rebecca E. A. , Côté Sébastien , Lee Chang-Seuk , Miao Haosen , Ramakrishnan Krithika , Palma Matteo , Dafydd Jones D.
Published: August 2024

Carbon nanotube field effect transistors (CNT-FET) hold great promise as next generation miniaturised biosensors. One bottleneck is modelling how proteins, with their distinctive electrostatic surfaces, interact with the CNT-FET to modulate conductance. Using advanced sampling molecular dynamics combined with non-canonical amino acid chemistry, we model protein electrostatic potential imparted on single walled CNTs (SWCNTs). We focus on using β-lactamase binding protein (BLIP2) as the receptor as it binds the antibiotic degrading enzymes, β-lactamases (BLs). BLIP2 is attached via the single selected residue to SWCNTs using genetically encoded phenyl azide photochemistry. Our devices detect two different BLs, TEM-1 and KPC-2, with each BL generating distinct conductance profiles due to their differing surface electrostatic profiles. Changes in conductance match the model electrostatic profile sampled by the SWCNTs on BL binding. Thus, our modelling approach combined with residue-specific receptor attachment could provide a general approach for systematic CNT-FET biosensor construction.
Spatially controllable and mechanically switchable isomorphous organoferroeleastic crystal optical waveguides and networks
Authors: Ranjan Subham , Kumar Avulu Vinod , Chandrasekar Rajadurai , Takamizawa Satoshi
Published: August 2024

The precise, reversible, and diffusionless shape-switching ability of organic ferroelastic crystals, while maintaining their structural integrity, positions them as promising materials for next-generation hybrid photonic devices. Herein, we present versatile bi-directional ferroelasticity and optical waveguide properties of three isomorphous, halogen-based, Schiff base organic crystals. These crystals exhibit sharp bending at multiple interfaces driven by molecular movement around the CH = N bond and subsequent 180° rotational twinning, offering controlled light path manipulation. The ferroelastic nature of these crystals allowed the construction of robust hybrid photonic structures, including Z-shaped configurations, closed-loop networks, and staircase-like hybrid optical waveguides. This study highlights the potential of shape-switchable organoferroelastic crystals as waveguides for applications in programmable photonic devices.
Tough double-bouligand architected concrete enabled by robotic additive manufacturing
Authors: Prihar Arjun , Gupta Shashank , Esmaeeli Hadi S. , Moini Reza
Published: August 2024

Nature has developed numerous design motifs by arranging modest materials into complex architectures. The damage-tolerant, double-bouligand architecture found in the coelacanth fish scale is comprised of collagen fibrils helically arranged in a bilayer manner. Here, we exploit the toughening mechanisms of double-bouligand designs by engineering architected concrete using a large-scale two-component robotic additive manufacturing process. The process enables intricate fabrication of the architected concrete components at large-scale. The double-bouligand designs are benchmarked against bouligand and conventional rectilinear counterparts and monolithic casts. In contrast to cast concrete, double-bouligand design demonstrates a non-brittle response and a rising R-curve, due to a hypothesized bilayer crack shielding mechanism. In addition, interlocking behind and crack deflection ahead of the crack tip in bilayer double-bouligand architected concrete elicits a 63% increase in fracture toughness compared to cast counterparts.
Adipocyte deletion of the oxygen-sensor PHD2 sustains elevated energy expenditure at thermoneutrality
Authors: Wang Rongling , Gomez Salazar Mario , Pruñonosa Cervera Iris , Coutts Amanda , French Karen , Pinto Marlene Magalhaes , Gohlke Sabrina , García-Martín Ruben , Blüher Matthias , Schofield Christopher J. , Kourtzelis Ioannis , Stimson Roland H. , Bénézech Cécile , Christian Mark , Schulz Tim J. , Gudmundsson Elias F. , Jennings Lori L. , Gudnason Vilmundur G. , Chavakis Triantafyllos , Morton Nicholas M. , Emilsson Valur , Michailidou Zoi
Published: August 2024

Enhancing thermogenic brown adipose tissue (BAT) function is a promising therapeutic strategy for metabolic disease. However, predominantly thermoneutral modern human living conditions deactivate BAT. We demonstrate that selective adipocyte deficiency of the oxygen-sensor HIF-prolyl hydroxylase (PHD2) gene overcomes BAT dormancy at thermoneutrality. Adipocyte-PHD2-deficient mice maintain higher energy expenditure having greater BAT thermogenic capacity. In human and murine adipocytes, a PHD inhibitor increases Ucp1 levels. In murine brown adipocytes, antagonising the major PHD2 target, hypoxia-inducible factor-(HIF)−2a abolishes Ucp1 that cannot be rescued by PHD inhibition. Mechanistically, PHD2 deficiency leads to HIF2 stabilisation and binding of HIF2 to the Ucp1 promoter, thus enhancing its expression in brown adipocytes. Serum proteomics analysis of 5457 participants in the deeply phenotyped Age, Gene and Environment Study reveal that serum PHD2 associates with increased risk of metabolic disease. Here we show that adipose-PHD2-inhibition is a therapeutic strategy for metabolic disease and identify serum PHD2 as a disease biomarker.
Variations of organic functional chemistry in carbonaceous matter from the asteroid 162173 Ryugu
Authors: De Gregorio Bradley , Cody George D. , Stroud Rhonda M. , David Kilcoyne A. L. , Sandford Scott , Le Guillou Corentin , Nittler Larry R. , Barosch Jens , Yabuta Hikaru , Martins Zita , Kebukawa Yoko , Okumura Taiga , Hashiguchi Minako , Yamashita Shohei , Takeichi Yasuo , Takahashi Yoshio , Wakabayashi Daisuke , Engrand Cécile , Bejach Laure , Bonal Lydie , Quirico Eric , Remusat Laurent , Duprat Jean , Verdier-Paoletti Maximilien , Mostefaoui Smail , Komatsu Mutsumi , Mathurin Jérémie , Dazzi Alexandre , Deniset-Besseau Ariane , Dartois Emmanuel , Tamenori Yusuke , Suga Hiroki , Montagnac Gilles , Kamide Kanami , Shigenaka Miho , Matsumoto Megumi , Enokido Yuma , Yoshikawa Makoto , Saiki Takanao , Tanaka Satoshi , Terui Fuyuto , Nakazawa Satoru , Usui Tomohiro , Abe Masanao , Okada Tatsuaki , Yada Toru , Nishimura Masahiro , Nakato Aiko , Miyazaki Akiko , Yogata Kasumi , Yurimoto Hisayoshi , Nakamura Tomoki , Noguchi Takaaki , Okazaki Ryuji , Naraoka Hiroshi , Sakamoto Kanako , Tachibana Shogo , Watanabe Sei-ichiro , Tsuda Yuichi
Published: August 2024

Primordial carbon delivered to the early earth by asteroids and meteorites provided a diverse source of extraterrestrial organics from pre-existing simple organic compounds, complex solar-irradiated macromolecules, and macromolecules from extended hydrothermal processing. Surface regolith collected by the Hayabusa2 spacecraft from the carbon-rich asteroid 162173 Ryugu present a unique opportunity to untangle the sources and processing history of carbonaceous matter. Here we show carbonaceous grains in Ryugu can be classified into three main populations defined by spectral shape: Highly aromatic (HA), Alkyl-Aromatic (AA), and IOM-like (IL). These carbon populations may be related to primordial chemistry, since C and N isotopic compositions vary between the three groups. Diffuse carbon is occasionally dominated by molecular carbonate preferentially associated with coarse-grained phyllosilicate minerals. Compared to related carbonaceous meteorites, the greater diversity of organic functional chemistry in Ryugu indicate the pristine condition of these asteroid samples.
Leveraging artificial intelligence to identify the psychological factors associated with conspiracy theory beliefs online
Authors: Kunst Jonas R. , Gundersen Aleksander B. , Krysińska Izabela , Piasecki Jan , Wójtowicz Tomi , Rygula Rafal , van der Linden Sander , Morzy Mikolaj
Published: August 2024

Given the profound societal impact of conspiracy theories, probing the psychological factors associated with their spread is paramount. Most research lacks large-scale behavioral outcomes, leaving factors related to actual online support for conspiracy theories uncertain. We bridge this gap by combining the psychological self-reports of 2506 Twitter (currently X) users with machine-learning classification of whether the textual data from their 7.7 million social media engagements throughout the pandemic supported six common COVID-19 conspiracy theories. We assess demographic factors, political alignment, factors derived from theory of reasoned action, and individual psychological differences. Here, we show that being older, self-identifying as very left or right on the political spectrum, and believing in false information constitute the most consistent risk factors; denialist tendencies, confidence in one’s ability to spot misinformation, and political conservativism are positively associated with support for one conspiracy theory. Combining artificial intelligence analyses of big behavioral data with self-report surveys can effectively identify and validate risk factors for phenomena evident in large-scale online behaviors.