bluuebunny/crossref_metadata_2025_split huggingface dataset:
Magnetically driven winds from accretion disks in post-asymptotic giant branch binaries
Authors: Verhamme Olivier , Kluska Jacques , Ferreira Jonathan , Bollen Dylan , De Prins Toon , Kamath Devika , Van Winckel Hans 
Published: January 2024

Context. Jets are commonly detected in post-asymptotic giant branch (post-AGB) binaries and originate from an accretion process onto the companion of the post-AGB primary. These jets are revealed by high-resolution spectral time series.
Aims. This paper is part of a series. In this work, we move away from our previous parametric modelling and include a self-similar wind model that allows the physical properties of post-AGB binaries to be characterised. This model describes magnetically driven jets from a thin accretion disk threaded by a large-scale, near equipartition vertical field.
Methods. We expanded our methodology in order to simulate the high-resolution dynamic spectra coming from the obscuration of the primary by the jets launched by the companion. We present the framework to exploit the self-similar jet models for post-AGB binaries. We performed a parameter study to investigate the impact of different parameters (inclination, accretion rate, inner and outer launching radius) on the synthetic spectra.
Results. We successfully included the physical jet models into our framework. The synthetic spectra have a very similar orbital phase coverage and absorption strengths as the observational data. The magnetohydrodynamic (MHD) jet models provide a good representation of the actual jet creation process in these evolved binaries. Challenges remain, however, as the needed high-accretion rate would induce accretion disks that are too hot in comparison to the data. Moreover, the rotational signature of the models is not detected in the observations. In future research, we will explore models with a higher disk ejection efficiency and even lower magnetisation in order to solve some of the remaining discrepancies between the observed and synthetic dynamic spectra.
Formation of a streamer blob via the merger of multiple plasma clumps below 2 R⊙
Authors: Li Haiyi , Huang Zhenghua , Deng Kaiwen , Fu Hui , Xia Lidong , Song Hongqiang , Xiong Ming , Wei Hengyuan , Qi Youqian , Zhang Chao 
Published: January 2024

Context. Propagating streamer blobs could be an important source of disturbances in the solar wind. Direct observations of the formation of streamer blobs could be a proxy for understanding the formation of small-scale structures and disturbances in the solar wind.
Aims. We aim to investigate how a streamer blob is formed before it is observed in the outer corona.
Methods. Using special coordinated observations from SOHO/LASCO, GOES/SUVI, and SDO/AIA, we studied the precursors of a streamer blob seen in the corona below 2.0 solar radii (R⊙).
Results. We find that the streamer blob formed due to the gradual merging of three clumps of brightenings initiated from the lower corona at about 1.8 R⊙, which was likely driven by the expansion of the loop system at the base of the streamer. The acceleration of the blob starts at 1.9 R⊙ or lower. It propagates along the south flank of the streamer, where an expanding elongated brightening occurs coincidentally.
Conclusions. Our observations demonstrate that formation of a streamer blob is a complex process. We suggest that the expansion of the loop results in a pinching-off flux-rope-like blob at the loop apex below 2 R⊙. When the blob moves outward, it can be transferred across the overlying loops through interchange or component magnetic reconnection and is then released into the open field system. When the blob moves toward open field lines, interchange magnetic reconnection might also occur, and that can accelerate the plasma blob intermittently, while allowing it to transfer across the open field lines. Such dynamics in a streamer blob might further trigger small-scale disturbances in the solar wind such as switchbacks in the inner heliosphere.
The GAPS Programme at TNG
Authors: Ruggieri A. , Desidera S. , Biazzo K. , Pinamonti M. , Marzari F. , Mantovan G. , Sozzetti A. , Bonomo A. S. , Lanza A. F. , Malavolta L. , Claudi R. , Damasso M. , Gratton R. , Nardiello D. , Benatti S. , Bignamini A. , Andreuzzi G. , Borsa F. , Cabona L. , Knapic C. , Molinari E. , Pino L. , Zingales T. 
Published: January 2024

Context. Planets in binary systems are a fascinating and yet poorly understood phenomenon. Since there are only a few known large-separation systems in which both components host planets, characterizing them is a key target for planetary science.
Aims. In this paper, we aim to carry out an exhaustive analysis of the interesting XO-2 system, where one component (XO-2N) appears to be a system with only one planet, while the other (XO-2S) has at least three planets.
Methods. Over the last 9 yr, we have collected 39 spectra of XO-2N and 106 spectra of XO-2S with the High Accuracy Radial velocity Planet Searcher for the Northern emisphere (HARPS-N) in the framework of the Global Architecture of Planetary Systems (GAPS) project, from which we derived precise radial velocity (RV) and activity indicator measurements. Additional spectroscopic data from the High Resolution Echelle Spectrometer (HIRES) and from the High Dispersion Spectrograph (HDS), and the older HARPS-N data presented in previous papers, have also been used to increase the total time span. We also used photometric data from TESS to search for potential transits that have not been detected yet. For our analysis, we mainly used PyORBIT, an advanced Python tool for the Bayesian analysis of RVs, activity indicators, and light curves.
Results. We found evidence for an additional long-period planet around XO-2S and characterized the activity cycle likely responsible for the long-term RV trend noticed for XO-2N. The new candidate is an example of a Jovian analog with m sin i ~ 3.7 MJ, a ~ 5.5 au, and e = 0.09. We also analyzed the stability and detection limits to get some hints about the possible presence of additional planets. Our results show that the planetary system of XO-2S is at least one order of magnitude more massive than that of XO-2N. The implications of these findings for the interpretation of the previously known abundance difference between components are also discussed.
The globular cluster VVV CL002 falling down to the hazardous Galactic centre
Authors: Minniti Dante , Matsunaga Noriyuki , Fernández-Trincado José G. , Otsubo Shogo , Sarugaku Yuki , Takeuchi Tomomi , Katoh Haruki , Hamano Satoshi , Ikeda Yuji , Kawakita Hideyo , Lucas Philip W. , Smith Leigh C. , Petralia Ilaria , Rita Garro Elisa , Saito Roberto K. , Alonso-García Javier , Gómez Matías , Gabriela Navarro María 
Published: January 2024

Context. The Galactic centre is hazardous for stellar clusters because of the strong tidal force in action there. It is believed that many clusters were destroyed there and contributed stars to the crowded stellar field of the bulge and the nuclear stellar cluster. However, the development of a realistic model to predict the long-term evolution of the complex inner Galaxy has proven difficult, and observations of surviving clusters in the central region would provide crucial insights into destruction processes.
Aims. Among the known Galactic globular clusters, VVV CL002 is the closest to the centre, at 0.4 kpc, but has a very high transverse velocity of 400 km s−1. The nature of this cluster and its impact on Galactic astronomy need to be addressed with spectroscopic follow up.
Methods. Here we report the first measurements of its radial velocity and chemical abundance based on near-infrared high-resolution spectroscopy.
Results. We find that this cluster has a counter-rotating orbit constrained within 1.0 kpc of the centre, and as close as 0.2 kpc at the perigalacticon, confirming that the cluster is not a passerby from the halo but a genuine survivor enduring the harsh conditions of the tidal forces of the Galactic mill. In addition, its metallicity and α abundance ([α/Fe] ≃ +0.4 and [Fe/H] = −0.54) are similar to those of some globular clusters in the bulge. Recent studies suggest that stars with such α-enhanced stars were more common at 3–6 kpc from the centre around 10 Gyr ago.
Conclusions. We infer that VVV CL002 was formed outside but is currently falling down to the centre, showcasing a real-time event that must have occurred to many clusters a long time ago.
Analysis of the public HARPS/ESO spectroscopic archive
Authors: Perdelwitz V. , Trifonov T. , Teklu J. T. , Sreenivas K. R. , Tal-Or L. 
Published: January 2024

Context. Magnetic activity is currently the primary limiting factor in radial velocity (RV) exoplanet searches. Even inactive stars, such as the Sun, exhibit RV jitter of the order of a few m s−1 due to active regions on their surfaces. Time series of chromospheric activity indicators, such as the Ca II H&K lines, can be utilized to reduce the impact of such activity phenomena on exoplanet search programmes. In addition, the identification and correction of instrumental effects can improve the precision of RV exoplanet surveys.
Aims. We aim to update the HARPS -RVBANK RV database and include an additional 3.5 yr of time series and Ca II H&K lines (R′HK) chromospheric activity indicators. This additional data will aid in the analysis of the impact of stellar magnetic activity on the RV time series obtained with the HARPS instrument. Our updated database aims to provide a valuable resource for the exoplanet community in understanding and mitigating the effects of such stellar magnetic activity on RV measurements.
Methods. The new HARPS-RVBANK database includes all stellar spectra obtained with the HARPS instrument prior to January 2022. The RVs corrected for small but significant nightly zero-point variations were calculated using an established method. The R′HK estimates were determined from both individual spectra and co-added template spectra with the use of model atmospheres. As input for our derivation of R′HK, we derived stellar parameters from co-added, high signal-to-noise ratio templates for a total of 3230 stars using the stellar parameter code SPECIES.
Results. The new version of the HARPS RV database has a total of 252 615 RVs of 5239 stars. Of these, 195 387 have R′HK values, which corresponds to 77% of all publicly available HARPS spectra. Currently, this is the largest public database of high-precision (down to ~1 m s−1) RVs, and the largest compilation of R′HK measurements. We also derived lower limits for the RV jitter of F-, G-, and K-type stars as a function of R′HK.
The enigmatic dance of the HD 189733A system: A quest for accretion
Authors: Colombo S. , Pillitteri I. , Petralia A. , Orlando S. , Micela G. 
Published: January 2024

Context. Several studies suggest that the emission properties of a star can be significantly affected by its interaction with a nearby planet through magnetic fields or interaction between their respective winds. However, the actual observability of these effects remains a subject of debate. An illustrative example is the HD 189733A system: certain characteristics of its emissions have been interpreted as indicative of ongoing interactions between the star and its associated planet. Other studies attribute these characteristics to the coronal activity of the star.
Aims. In this study we aimed to investigate whether the observed stellar X-ray flare events, which appear to be in phase with the planetary period in the HD 189733A system, could be attributed to the accretion of the planetary wind onto the stellar surface or if they resulted from an interaction between the planetary and stellar winds.
Methods. We developed a 3D magnetohydrodynamic model with the PLUTO code that describes the system HD 189733A , including the central host star and its hot Jupiter along with their respective winds. The effects of gravity and the magnetic fields of both the star and the planet are taken into account.
Results. Our analysis reveals that, in the cases examined in this study, the accretion scenario is only viable when the stellar magnetic field strength is at 5 G and the planetary magnetic field strength is at 1 G. In this scenario, the Rayleigh-Taylor instabilities lead to the formation of an accretion column that connects the star to the planet. Once formed the accretion column remains stable for the duration of the simulation. The accretion column produces an accretion rate of the order of 1012 g s−1 and shows an average density of about 107 cm−3. In the other case explored, the accretion column does not form because the Rayleigh-Taylor instability is suppressed by the stronger magnetic field intensities assumed for both the star and the planet. We synthesized the emission resulting from the shocked planetary wind and found that the total X-ray emission ranges from 5 × 1023 to 1024 erg s−1.
Conclusions. In the case of accretion, the emission originating from the hotspot cannot be distinguished from the coronal activity. Also, the interaction between the planetary and stellar winds cannot be responsible for the X-ray emission, as the total emission produced is about four orders of magnitude lower than the average X-ray luminosity of the star.
Density discrepancy between transit-timing variations and radial velocity: Insights from the host star composition
Authors: Adibekyan V. , Sousa S. G. , Delgado Mena E. , Santos N. C. , Israelian G. , Barros S. C. C. , Martirosyan Zh. , Hakobyan A. A. 
Published: January 2024

Context. The determination of planetary densities from the masses derived with the radial velocity (RV) and transit-timing variation (TTV) methods reveals discrepancies. Specifically, planets detected through RV exhibit higher densities than those detected through TTV, even though their radii are similar. Understanding the origins of these discrepancies is crucial and timely, especially with upcoming ground- and space-based missions dedicated to exoplanet research.Aims. We explored the possibility that the discrepant mass/densities in the TTV and RV populations might be linked to the properties of the environments in which these planets are formed.Methods. For the largest currently available sample of FGK-type stars hosting low-mass TTV and RV planets, we determined the host star abundances. Then, by employing a simple stoichiometric model, we used these abundances to estimate the iron-to-silicate mass fraction (firon) and the water-mass fraction (wf) of the protoplanetary disks. We also calculated the kinematic properties of the host stars.Results. We observed an indication that the hosts of TTV planets have slightly higherfironand lowerwfvalues than their RV counterparts. This suggests that TTV planets (without considering their atmospheres) are denser than RV planets on average, which implies that larger atmospheres on TTV planets are required to account for their overall lower densities. However, we also note differences in the properties of the planets, such as their orbital periods, and variations in the quality of the spectroscopic data, which may have an impact on these results.Conclusions. Exploring the TTV-RV mass and/or density discrepancy through a chemical analysis of the host star holds promise for future research, particularly with larger sample sizes and higher-quality data. Meanwhile, the provided detailed host star abundances can be employed to study the composition of the planets within the current sample, thereby contributing to a better understanding of the aforementioned discrepancy.
Einfluss und Machbarkeit eines appbasierten Feedbacks im curricularen Szenariotraining der Notfallmedizin: eine prospektive, kontrollierte Observationsstudie
Authors: Landwehrt Jan , Van der Poel Daniela , Brause Verena , Wagner Nana , Ohlenburg Hendrik , Zarbock Alexander , Hessler Michael , Joos Gunther S. , Schnabel Alexander 
Published: January 2024

ZusammenfassungIm Rahmen der kompetenzbasierten Facharztausbildung wurden bereits Kernkompetenzen im Sinne von Entrustable Professional Activities (EPA) in der Anästhesiologie definiert. Appunterstützte formative Assessments und Feedbacks könnten die Umstellung zu einer kompetenzbasierten Lehre erleichtern.Die Studierenden der Humanmedizin des Wintersemesters 2022/23, die den curricularen Kurs Notfallmedizin 2 der Universitätsklinik Münster besuchten, erhielten entweder im Anschluss an ein Szenariotraining mithilfe einer App ein systematisches oder unsystematisches Feedback.Insgesamt wurden 104 Studierende (50 in der Experimental-, 54 in der Kontrollgruppe) eingeschlossen. Die Evaluationsergebnisse unterschieden sich nicht zwischen beiden Gruppen (p = 0,225). Die Experimental- (14,12 min [± 4,37]) im Vergleich zur Kontrollgruppe (11,15 min [± 3,32]) erhielt im Mittel ein 2,97 min längeres Feedback (p < 0,001). Der Vergleich der Ergebnisse der Selbsteinschätzung des Supervisionslevels zu den Zeitpunkten vor (p = 0,051) und nach dem Kurs (p = 0,134) zeigten keine signifikanten Unterschiede. Für den Vergleich zwischen der Selbst- (durch den Studierenden nach seiner Teamleiterrolle) und Fremdeinschätzung (durch den/die Dozent*in) nach dem Fallbeispiel bestanden keine signifikanten Unterschiede (p = 0,480).Die vorliegende Observationsstudie hat gezeigt, dass ein appbasiertes formatives Feedback implementiert werden kann. Allerdings hatte dies keine Auswirkungen auf die Evaluationsergebnisse der Studierenden bzw. Selbst- und Fremdeinschätzungen zum Supervisionsbedarf.
Vasorelaxant effects of ellagitannins isolated from Cuphea carthagenensis
Authors: Isla Kaori Katiuska Yamaguchi , Tanae Mirtes Midori , de Lima-Landman Maria Teresa Riggio , de Magalhães Pedro Melillo , Lapa Antônio José , Souccar Caden 
Published: January 2024

Abstract
Cuphea carthagenensis (Jacq.) J. F. Macbr. is a popular plant in Brazilian folk medicine owing to its hypotensive and central nervous system depressant effects. This study aimed to validate the hypotensive effect of the plantʼs aqueous extract (AE) in rats and examine the vascular actions of three hydrolyzable tannins, oenothein B, woodfordin C, and eucalbanin B, isolated from AE. Systolic blood pressure in unanesthetized rats was determined using the non-invasive tail-cuff method. Oral treatment of normotensive rats with 0.5 and 1.0 g/kg/day AE induced a dose-related hypotensive effect after 1 week. In rat aortic rings pre-contracted with noradrenaline, all ellagitannins (20 – 180 µM) induced a concentration-related vasorelaxation. This effect was blocked by either removing the endothelium or pre-incubating with NG-nitro-l-arginine methyl ester (10 µM), an inhibitor of nitric oxide (NO) synthase. In KCl-depolarized rat portal vein preparations,
the investigated compounds did not affect significantly the maximal contractile responses and pD2 values of the concentration-response curves to CaCl2. Our results demonstrated the hypotensive effect of C. carthagenensis AE in unanesthetized rats. All isolated ellagitannins induced vasorelaxation in vitro via activating NO synthesis/NO release from endothelial cells, without altering the Ca2+ influx in vascular smooth muscle preparations. Considering the low oral bioavailability of ellagitannins, the determined in vitro actions of these compounds are unlikely to account for the hypotensive effect of AE in vivo. It remains to be determined the role of the bioactive ellagitannin-derived metabolites in the hypotensive effect observed after oral treatment of unanesthetized rats with the plant extract.
Beabsichtigte und unbeabsichtigte Wirkungen von E-Zigaretten in klinischen Studien – ein Plädoyer für (mehr) Transparenz
Authors: Hanewinkel Reiner , Ulbricht Sabina 
Published: January 2024

ZusammenfassungE-Zigaretten werden in klinischen Studien zur Tabakentwöhnung eingesetzt. Aufgrund der Gesundheitsrisiken, die mit dem Gebrauch von E-Zigaretten verbunden sind, sollten die Ergebnisse klinischer Studien vollständig berichtet werden, einschließlich des fortgesetzten ausschließlichen Gebrauchs und des gemeinsamen Gebrauchs von Tabak und E-Zigaretten. Die Ergebnisse zur Nikotinentwöhnung sollten als primärer Endpunkt ebenso wie die Analyse der bloßen Beendigung des Tabakkonsums berichtet werden. Da es derzeit keine stichhaltigen Belege dafür gibt, dass die Reduzierung des Zigarettenkonsums wesentliche gesundheitliche Vorteile mit sich bringt, sollte die Reduzierung des Zigarettenkonsums nicht als Gesundheitsendpunkt in klinischen Studien verwendet werden. Die fortbestehende Nikotinabhängigkeit sollte als „unerwünschtes Ereignis“ in die Berichterstattung über die Studienergebnisse aufgenommen werden.
Difference of Knee Strength Recovery Between Revision and Primary ACL
Reconstruction
Authors: Dauty Marc , Combes Philippe , Gernigon Marie , Menu Pierre , Crenn Vincent , Daley Pauline , Fouasson-Chailloux Alban 
Published: January 2024

AbstractDifferent grafting procedures are available to restore knee stability after
revision anterior cruciate ligament (ACL) reconstruction. We compared knee
strength recovery between ACL revision surgery and primary reconstruction. One
hundred and ten patients with ACL revision surgery were matched with 110
patients with primary reconstruction based on the graft procedure. The
isokinetic knee strength had been assessed for the first 9 months post-surgery.
Knee laxity, function, and activity score were also evaluated. Limb symmetry
index for knee extensor and flexor strength was not different at 4-, 6- and
9-months post-surgery between revision surgery and primary reconstruction. These
results depended on ipsilateral or contralateral graft choice. Ipsilateral
hamstring tendon (HT) and contralateral bone-patellar-tendon-bone (BPTB) graft
procedures were similar for a revision of a BPTB graft failure. Contralateral HT
procedure was better than ipsilateral BPTB procedure for a revision of a HT
graft failure. The early recovery of isokinetic knee strength after ACL revision
surgery regardless of the HT or BPTB procedures, was similar to the recovery
after primary ACL reconstruction with the same graft technique. These results
apparently depended on a temporary quadriceps arthrogenic muscle inhibition and
on a persistent donor site morbidity, concerning the new and the previous
grafts, respectively.
N-Heterocyclic Carbene Catalysis for Facile Access to Pentasubstituted 4H-Pyran Derivatives
Authors: Jin Zhichao , Ren Shi-Chao , Peng Xiaolin , Wang Yulin , Huang Yixian , Zhang Sheng 
Published: January 2024

AbstractThe synthesis of polysubstituted 4H-pyran derivatives has attracted considerable attention due to its wide application in agrochemicals, pharmaceuticals, and other functional molecules. We report an N-heterocyclic carbene-catalyzed [3+3] annulation reaction of β-ketone esters with enynals for rapid access to pentasubstituted 4H-pyran derivatives through a regioselective activation of the ynal. A series of 4H-pyran derivatives bearing various substituents were obtained in moderate to excellent yields. This method could find further applications in the synthesis of structurally diverse 4H-pyran-derived functional molecules from readily available starting materials.