bluuebunny/crossref_metadata_2025_split huggingface dataset:
The enigma of Li-rich giants and its relation with temporal variations observed in radial velocity and stellar activity signals
Authors: Rolo Inês , Delgado Mena Elisa , Tsantaki Maria , Gomes da Silva João 
Published: July 2024

Context. Despite the large number of studies focused on the characterisation of Li-rich stars and understanding the mechanisms leading to such enrichment, their origin remains a mystery.
Aims. Magnetic activity, particularly the phenomena usually associated with it (e.g. spots and plages), and the Li abundance (A(Li)) of stars, are in general thought to be connected. As of today, however, just how they are connected is unclear. In this work, we study a sample of young but evolved intermediate-mass red giants that are inhabitants of open clusters where planets have been searched for. Our aim is to use radial velocity (RV) and stellar activity indicator signals to look for relations between Li abundances and stellar activity or variability.
Methods. We explored how the standard deviation (STD), peak-to-peak amplitude (PTP), mean, and median of typical stellar activity indicators (BIS, FWHM, Teff, and Hα index) change as a function of the Li content of 82 red giants. Furthermore, we computed weighted Pearson correlation coefficients (ρw) between time series of RV measurements and the stellar activity indicators for the stars in our sample. To aid our results, we also studied generalized Lomb–Scargle periodograms (GLSP) to capture possible significant periodic temporal variations in our data.
Results. Our analysis indicates that the STD and PTP of BIS and FWHM, the mean and median of the Hα index, and υ sin(i) increase exponentially with A(Li) in our sample of red giants. Significant temporal variations and correlations between RVs and activity indicators also tend to be found preferentially for stars where high A(Li) is observed. Most of the Li-rich stars in our sample either show strong correlations of RV with at least one of the stellar activity indicators or reveal significant periodic temporal variations in their GLSPs of stellar activity indicators that are consistent with those found for RV.
Dynamical evolution timescales for the triple supermassive black hole system in NGC 6240
Authors: Berczik P. , Sobolenko M. , Ishchenko M. 
Published: July 2024

Aims. Based on the available observational data from the literature, we analysed the dynamics of the NGC 6240 galaxy central supermassive black hole (SMBH) system.
Methods. For the dynamical modelling of this triple SBMH system, we used the massively parallel and GPU accelerated φ-GPU direct summation N-body code. Following a long-timescale modelling of the triple system, we carried out a very detailed time output analysis of the von Zeipel–Lidov–Kozai (ZLK) oscillations for the black holes.
Results. According to our Newtonian simulation results, for all models and randomisations, the bound system from S1+S2 components formed at ≈3.6 Myr. The formation of the bound hierarchical triple system S+N occurred at ≈18 Myr. Over the course of these Newtonian simulations of the evolution of the triple SMBH system and the surrounding environment in NGC 6240, ZLK oscillations were detected (in most cases) for the binary components. The inclination angle between the orbital angular momentum of binary components aptly coincides with the theoretical calculations of the ZLK mechanism.
Conclusions. In our set of randomised 15 Newtonian N-body dynamical galaxy models in 13 systems, we were able to detect a ZLK mechanism. In contrast, our extra few-body post-Newtonian runs (for one randomisation case) show it is only for the large inner binary initial eccentricity (in our case ≳0.9) that we are able to observe the possibility of the inner binary merging, due to the post-Newtonian energy radiation effects. For the lower eccentricity cases, the test runs show no sign of possible merging or any ZLK oscillations in the system.
The Solar System could have formed in a low-viscosity disc: A dynamical study from giant planet migration to the Nice model
Authors: Griveaud P. , Crida A. , Petit A. C. , Lega E. , Morbidelli A. 
Published: July 2024

Context. In the context of low-viscosity protoplanetary discs (PPDs), the formation scenarios of the Solar System should be revisited. In particular, the Jupiter-Saturn pair has been shown to lock in the 2:1 mean motion resonance while migrating generally inwards, making the Grand Tack scenario impossible.
Aims. We explore what resonant chains of multiple giant planets can form in a low-viscosity disc, and whether these configurations can evolve into forming the Solar System in the post gas disc phase.
Methods. We used hydrodynamical simulations with the code FARGOCA to study the migration of the giant planets in a disc with viscosity parameter of α = 10−4. After a transition phase to a gas-less configuration, we studied the stability of the obtained resonant chains through their interactions with a disc of leftover planetesimals by performing N-body simulations using rebound.
Results. The gaps opened by giant planets are wider and deeper for lower viscosity, reducing the damping effect of the disc. Thus, when planets enter a resonance, the resonant angle remains closer to circulation, making the chain weaker. Exploring numerous configurations, we found five stable resonant chains of four or five planets. In a thin (cold) PPD, the four giant planets revert their migration and migrate outwards. After disc dispersal, under the influence of a belt of planetesimals, some resonant chains undergo an instability phase while others migrate smoothly over a billion years. For three of our resonant chains, about ~1% of the final configurations pass the four criteria to fit the Solar System. The most successful runs are obtained for systems formed in a cold PPD with a massive planetesimal disc.
Conclusions. This work provides a fully consistent study of the dynamical history of the Solar System’s giant planets, from the protoplanetary disc phase up to the giant planet instability. Although building resonant configurations is difficult in low-viscosity discs, we find it possible to reproduce the Solar System from a cold, low-viscosity protoplanetary disc.
Timing irregularities and glitches from the pulsar monitoring campaign at IAR
Authors: Zubieta E. , García F. , del Palacio S. , Araujo Furlan S. B. , Gancio G. , Lousto C. O. , Combi J. A. , Espinoza C. M. 
Published: July 2024

Context. Pulsars have a very stable rotation overall. However, sudden increases in their rotation frequency, known as glitches, perturb their evolution. While many observatories commonly detect large glitches, small glitches are harder to detect because of the lack of daily cadence observations over long periods of time (years).
Aims. We aim to explore and characterise the timing behaviour of young pulsars on daily timescales, looking for small glitches and other irregularities, in order to further our comprehension of the real distribution of glitch sizes. Our findings have consequences for the theoretical modelling of the glitch mechanism.
Methods. We observed six pulsars with up to daily cadence between December 2019 and January 2024 with the two antennas of the Argentine Institute of Radio Astronomy (IAR). We used standard pulsar timing tools to obtain the times of arrival of the pulses and to characterise the pulsar’s rotation. We developed an algorithm to look for small timing events in the data and calculate the changes in the frequency (ν) and its derivative (ν̇) at those epochs.
Results. We find that the rotation of all pulsars in this dataset is affected by small step changes in ν and ν̇. Among them, we find three new glitches that have not been reported before: two glitches in PSR J1048−5832 with relative sizes of Δν/ν = 9.1(4)×10−10 and Δν/ν = 4.5(1)×10−9, and one glitch in the Vela pulsar with a size of Δν/ν = 2.0(2)×10−10. We also report new decay terms on the 2021 Vela giant glitch, and on the 2022 giant glitches in PSR J0742−2822 and PSR J1740−3015, respectively. In addition, we find that the red noise contribution significantly diminished in PSR J0742−2822 after its giant glitch in 2022.
Conclusions. Our results highlight the importance of high-cadence monitoring with an exhaustive analysis of the residuals to better characterise the distribution of glitch sizes and to deepen our understanding of the mechanisms behind glitches, red noise, and timing irregularities.
A Markovian description of the multi-level source function and its application to the Lyman series in the Sun
Authors: Krikova K. , Pereira T. M. D. 
Published: July 2024

Aims. We introduce a new method to calculate and interpret indirect transition rates populating atomic levels using Markov chain theory. Indirect transition rates are essential to evaluate interlocking in a multi-level source function, which quantifies all the processes that add and remove photons from a spectral line. A better understanding of the multi-level source function is central to interpret optically thick spectral line formation in stellar atmospheres, especially outside local thermodynamical equilibrium (LTE).
Methods. We compute the level populations from a hydrogen model atom in statistical equilibrium, using the solar FALC model, a 1D static atmosphere. From the transition rates, we reconstruct the multi-level source function using our new method and compare it with existing methods to build the source function. We focus on the Lyman series lines and analyze the different contributions to the source functions and synthetic spectra.
Results. Absorbing Markov chains can represent the level-ratio solution of the statistical equilibrium equation and can therefore be used to calculate the indirect transition rates between the upper and lower levels of an atomic transition. Our description of the multi-level source function allows a more physical interpretation of its individual terms, particularly a quantitative view of interlocking. For the Lyman lines in the FALC atmosphere, we find that interlocking becomes increasingly important with order in the series, with Ly-α showing very little, but Ly-β nearly 50% and Ly-γ about 60% contribution coming from interlocking. In some cases, this view seems opposed to the conventional wisdom that these lines are mostly scattering, and we discuss the reasons why.
Conclusions. Our formalism to describe the multi-level source function is general and can provide more physical insight into the processes that set the line source function in a multi-level atom. The effects of interlocking for lines formed in the solar chromosphere can be more important than previously thought, and our method provides the basis for further exploration.
Periodic variable A-F spectral type stars in the southern TESS continuous viewing zone
Authors: Skarka M. , Henzl Z. 
Published: July 2024

Aims. Our primary objective is to accurately identify and classify the variability of A-F stars in the southern continuous viewing zone of the TESS satellite. The brightness limit was set to 10 mag to ensure the utmost reliability of our results and allow for spectroscopic follow-up observations using small telescopes. We aim to compare our findings with existing catalogues of variable stars.
Methods. The light curves from TESS and their Fourier transform were used to manually classify stars in our sample. Cross-matching with other catalogues was performed to identify contaminants and false positives.
Results. We have identified 1171 variable stars (51% of the sample). Among these variable stars, 67% have clear classifications, which includes δ Sct and γ Dor pulsating stars and their hybrids, rotationally variables, and eclipsing binaries. We have provided examples of the typical representatives of variable stars and discussed the ambiguous cases. We found 20 pairs of stars with the same frequencies and identified the correct source of the variations. Additionally, we found that the variations in 12 other stars are caused by contamination from the light of faint nearby large-amplitude variable stars. To compare our sample with other variable star catalogues, we have defined two parameters reflecting the agreement in identification of variable stars and their classification. This comparison reveals intriguing disagreements in classification ranging from 52 to 100%. However, if we assume that stars without specific types are only marked as variable, then the agreement is relatively good, ranging from 57 to 85% (disagreement 15–43%). We have demonstrated that the TESS classification is superior to the classification based on other photometric surveys.
Conclusions. The classification of stellar variability is complex and requires careful consideration. Caution should be exercised when using catalogue classifications.
Ethik der künstlichen Intelligenz in der Medizin
Authors: Maio Giovanni 
Published: July 2024

ZusammenfassungDie künstliche Intelligenz (KI) hält zunehmend Einzug in die Medizin, und es ist noch nicht absehbar, wie sie die Praxis der Medizin und auch das Selbstverständnis der Ärztinnen und Ärzte verändern wird. In dem Beitrag werden die ethischen Grenzen der KI erarbeitet, indem (1.) der in der KI schon enthaltende Reduktionismus des Zugangs auf die Welt erörtert wird, (2.) die problematischen Implikationen einer Algorithmisierung herausgearbeitet werden und (3.) die mangelnde menschliche Kontrolle als ethische Grenze markiert wird. Als Schlussfolgerung ergibt sich daraus, dass die KI zwar ein nützliches Werkzeug zur Unterstützung ärztlicher Beurteilung darstellt, dass sie aber unabdingbar auf menschliche Entscheidungshoheit angewiesen ist, um sich tatsächlich als segensreich für die Medizin zu erweisen.
Utility of Global Hemostatic Assays in Patients with Bleeding Disorders of Unknown Cause
Authors: Mehic Dino , Assinger Alice , Gebhart Johanna 
Published: July 2024

AbstractBleeding disorder of unknown cause (BDUC) is a diagnosis of exclusion after exhaustive evaluation of plasmatic coagulation and platelet function. This review explores the utility of global hemostatic assays as confirmatory tests and in elucidating the pathophysiology of BDUC. Unlike traditional hemostatic tests that focus on coagulation factors, global assays are conducted both in plasma and also whole blood. These assays provide a more comprehensive understanding of the cell-based model of coagulation, aid in the identification of plasmatic factor abnormalities that may reduce hemostatic capacity, and allow for the assessment of impaired platelet–endothelial interactions under shear stress, as well as hyperfibrinolytic states. While clinical tests such as skin bleeding time and global assays such as PFA-100 exhibit limited diagnostic capacity, the role of viscoelastic testing in identifying hemostatic dysfunction in patients with BDUC remains unclear. Thrombin generation assays have shown variable results in BDUC patients; some studies demonstrate differences compared with healthy controls or reference values, whereas others question its clinical utility. Fibrinolysis assessment in vitro remains challenging, with studies employing euglobulin clot lysis time, plasma clot lysis time, and fluorogenic plasmin generation yielding inconclusive or conflicting results. Notably, recent studies suggest that microfluidic analysis unveils shear-dependent platelet function defects in BDUC patients, undetected by conventional platelet function assays. Overall, global assays might be helpful for exploring underlying hemostatic impairments, when conventional hemostatic laboratory tests yield no results. However, due to limited data and/or discrepant results, further research is needed to evaluate the utility of global assays as screening tools.
An Interprofessional Graduate Student and Family Coaching Program in Naturalistic Communication Techniques
Authors: Gallegos Erin , Gevarter Cindy , Binger Cathy , Hartley Mary 
Published: July 2024

AbstractResearchers implemented a short-term cascading coaching model focusing on naturalistic developmental behavioral intervention with three participant triads. Triads consisted of a graduate student clinician, a minimally verbal child with autism spectrum disorder, and the child's parent. Coaching and intervention occurred during an interprofessional summer clinic that included graduate student clinicians from special education and speech and hearing sciences departments. The efficacy of short-term instruction, researcher coaching for student clinicians, and student clinician coaching of parents was evaluated using a multiple baseline across participants' design. The dependent variables were student clinician's and parent's use of elicitation techniques (creating communication temptations, waiting, and prompting) and response techniques (naturally reinforcing children's communication and providing spoken language models). Following coaching, parents and student clinicians from all triads increased their use of elicitation and response techniques, with very large effect sizes across all variables. Visual analysis findings suggest individualized differences and variability across triads. Implications for graduate education and parent coaching programs are discussed.
An Applied Model of Interprofessional Collaboration—Assessment (AMIC–A): A Process-Based Approach to Augmentative and Alternative Communication
Authors: Reuter-Yuill Lilith M. , Slim Lina M. , Kasper Tamara S. , Castaño Leslie , Dower Nikia R. , Gevarter Cindy B. 
Published: July 2024

AbstractSpeech-language pathologists and board-certified behavior analysts both provide important support services to children who are candidates for augmentative and alternative communication. Current assessment practices neglect critical socioecological factors that are necessary to inform communication-based interventions. By leveraging the unique knowledge, research, and expertise of both disciplines, an interprofessional approach to assessment may help realize individualized or precision interventions and personalized supports that address the unique communication needs of each person. The purpose of this article is to introduce a process-based approach to assessment called the “Applied Model of Interprofessional Collaboration—Assessment (AMIC–A).” The AMIC–A will be defined and detailed including the rationale for development, a description of the approach, and recommendations for implementation. A case study example is provided to illustrate implementation of the AMIC–A.
Pharmacotherapy for Venous Thromboprophylaxis following Total Hip or Knee Arthroplasty: A Systematic Review and Network Meta-analysis
Authors: Yong Bryan Song Jun , Ling Ryan Ruiyang , Ramanathan Kollengode , Fan Bingwen Eugene , Li Ruiqi , Poh Jane Wenjin , Tan Chuen Seng , Ho Sean Wei Loong , Rochwerg Bram , Arya Roopen 
Published: July 2024

AbstractThe optimal pharmacological prophylaxis for venous thromboembolism (VTE) after hip or knee arthroplasty is uncertain. We conducted a systematic review and network meta-analysis to compare the efficacy and safety of various medications. We searched multiple databases for randomized clinical trials (RCTs) comparing medications (including factor Xa inhibitors, factor IIa inhibitor, warfarin, unfractionated heparin [UFH], low-molecular-weight heparin [LMWH], aspirin, pentasaccharide) for VTE prophylaxis post-arthroplasty. Outcomes included any postoperative VTE identified with screening, major bleeding, and death. We used LMWH as the main comparator for analysis and performed trial sequential analysis (TSA) for each pairwise comparison. Certainty of evidence was assessed using GRADE (Grading of Recommendations, Assessments, Developments and Evaluations). We analyzed 70 RCTs (55,841 participants). Factor Xa inhibitors decreased postoperative VTE significantly compared with LMWH (odds ratio [OR]: 0.55, 95% confidence interval [CI]: 0.44–0.68, high certainty). Pentasaccharides probably reduce VTE (OR: 0.61, 95% CI: 0.36–1.02, moderate certainty), while the factor IIa inhibitor dabigatran may reduce VTE (OR: 0.75, 95% CI: 0.40–1.42, low certainty). UFH probably increases VTE compared with LMWH (OR: 1.31, 95% CI: 0.91–1.89, moderate certainty), and other agents like warfarin, aspirin, placebo, and usual care without thromboprophylaxis increase VTE (high certainty). Factor Xa inhibitors may not significantly affect major bleeding compared with LMWH (OR: 1.06, 95% CI: 0.81–1.39, low certainty). No medications had a notable effect on mortality compared with LMWH (very low certainty). TSA suggests sufficient evidence for the benefit of factor Xa inhibitors over LMWH for VTE prevention. Compared with LMWH and aspirin, factor Xa inhibitors are associated with reduced VTE after hip or knee arthroplasty, without an increase in bleeding and likely no impact on mortality.
Evolution of MNE strategies amid China’s changing institutions: a thematic review
Authors: Tse Caleb H. , Meyer Klaus E. , Pan Yigang , Chi Tailan 
Published: July 2024

AbstractAs China’s economy rose to become the second largest in the world, its institutions did not converge with those of other advanced economies as predicted by many Western observers; instead, China developed a distinct form of state-led capitalism. As a result, how multinational enterprises (MNEs) engage with China’s changing institutional context needs to be revisited. To this end, we review 331 papers on MNE strategies and operations in China published in top international business and management journals between 2001 and 2022. We first introduce the path of institutional change and the opportunities and challenges it created for MNEs in China. We focus on six aspects of MNE strategies and operations: market entry, strategic alliances, innovation and knowledge sharing, global value chain strategies, guanxi and relationship management, and non-market strategies. Our analysis of China’s institutional trajectory and of MNE strategies and operations points to three persistent institutional mechanisms of concern for MNEs: challenges to organizational legitimacy, protection of property rights, and the enabling and directing aspect of institutions created by industrial policies. Insights from this analysis point to future research needs on institutional nonlinearities and discontinuities, linkages between inward and outward investments, and geopolitical influences on national institutions.
Exploring loyalty drivers for smartphone and mobile carriers
Authors: Jo Hyeon , Park Do-Hyung 
Published: July 2024

AbstractSmartphones have permeated daily human life and play a role in various areas. Loyalty to smartphones holds significant implications for both businesses and customers. This study constructed a research model that considers smartphones as parallel to telecom services. The model comprises devices and mobile carriers as the main axes. The study designates exogenous variables as symmetric factors and common factors. The research collected empirical questionnaire responses from 357 smartphone users. Data analysis was conducted using partial least squares structural equation modeling. The findings revealed that brand image and apps are significantly related to device satisfaction. The results demonstrated that apps, corporate image, and perceived fees are crucial determinants of carrier satisfaction. The analysis also showed that both device satisfaction and mobile carrier satisfaction influence loyalty.