bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unified neutron star equations of state calibrated to nuclear properties
Authors: Malik Tuhin , Pais Helena , Providência Constança 
Published: June 2024

Context. Recently, a dataset of several equations of state (EOSs) for purely nucleonic stellar matter based on a nonlinear relativistic mean-field model prescription and constrained to properties of nuclear matter, state-of-the-art chiral effective-field theory calculations for low-density neutron matter, and astrophysical data were proposed.
Aims. In this work, 21 unified neutron star EOSs were chosen from that dataset in such a way that a large range of values of the slope of the symmetry energy at saturation is covered. Several quantities are calculated and discussed, such as the proton fraction and the direct Urca behavior, the density dependence of the speed of sound and the trace anomaly, the crust-core transition properties, the compatibility with astrophysical observations, and the neutron matter properties from chiral effective-field theory calculations and pQCD constraints.
Methods. We construct unified EOSs where the outer crust is given by the BSk22 functional and the inner crust is calculated from a compressible liquid drop approximation. The core is purely nucleonic; made of protons, neutrons, electrons, and muons; under charge neutrality; and in β-equilibrium conditions.
Results. The correlation of the slope of the symmetry energy at saturation with the crust-core transition density and proton fraction is analyzed, and equations that translate these relations are proposed. Moreover, the spectral representation for all the EOSs is given, which is a convenient representation to study quasi-periodic oscillations with realistic EOSs. We show that several of these EOSs have in the center of the most massive neutron star a speed of sound squared on the order of ≲0.5. Most of the EOSs predict a maximum central density on the order of about six times the nuclear saturation density. Three of the EOSs satisfy all of the constraints imposed. The 21 unified EOSs are available in the zenodo platform.
A quantitative explanation of the cyclotron-line variation in accreting magnetic neutron stars of super-critical luminosity
Authors: Loudas Nick , Kylafis Nikolaos D. , Trümper Joachim 
Published: June 2024

Context. Magnetic neutron stars (NSs) often exhibit a cyclotron resonant scattering feature (CRSF) in their X-ray spectra. Cyclotron lines are believed to be generated in the radiative shock in the accretion column. High-luminosity NSs show a smooth anti-correlation between the cyclotron-line centroid (ECRSF) and X-ray luminosity (LX).
Aims. It has been pointed out that the observed ECRSF − LX smooth anti-correlation in high-luminosity NSs is in tension with the theoretically predicted one, if the radiative shock is the site of cyclotron-line formation. The shock height increases approximately linearly with luminosity, while the dipolar magnetic field drops as the cubic power of distance, thereby implying that the cyclotron-line energy ought to decrease significantly when the luminosity increases by, say, an order of magnitude, which is contrary to observations. Since there is no other candidate site for the cyclotron-line formation, we re-examine the predicted rate of change of the cyclotron-line energy with luminosity at the radiative shock, taking a closer look at the Physics involved.
Methods. We developed a purely analytical model describing the overall dependence of the observed cyclotron energy centroid on the shock front’s height, including both the relativistic boosting and the gravitational redshift effects in our considerations. The relativistic boosting effect is due to the mildly relativistic motion of the accreting plasma upstream with respect to the shock’s reference frame.
Reults. We find that the cyclotron-line energy varies with (a) the shock height due to the dipolar magnetic field, (b) the Doppler boosting between the shock and bulk-motion frames, and (c) the gravitational redshift. We show that the relativistic effects noticeably weaken the predicted ECRSF − LX anti-correlation. We use our model to fit the data of the X-ray source V0332+53 that exhibits a weak negative correlation and demonstrate that the model fits the data impressively well, thereby alleviating the tension between observations and theory.
Conclusions. The reported weak anti-correlation between cyclotron-line centroid and X-ray luminosity in the supercritical accretion regime may be explained by the combination of the variation of the magnetic-field strength along the accretion column, the effect of Doppler boosting, and the gravitational redshift. As a result of these effects, the actual magnetic field on the surface of the neutron star may be a factor of ∼2 larger than the naively inferred value from the observed CRSF.
Expected evolution of the binary system PTF J2238+743015.1
Authors: Piersanti L. , Yungelson L. R. , Bravo E. 
Published: June 2024

Context. Binary systems harboring a low-mass CO WD and a He-rich donor are considered to be the possible progenitors of explosive events via He detonation, producing low-luminosity thermonuclear supernovae with a peculiar nucleosynthetic pattern. Recently, the binary system PTF J223857.11+743015.1 was proposed as a candidate for this kind of stars.
Aims. We investigate the evolution of the PTF J223857.11+743015.1 system, which is composed of a 0.75 M⊙ CO WD and a 0.390 M⊙ subdwarf. We consider the rotation of the WD component.
Methods. Using the FuNS code, we computed the evolution of the two stars simultaneously, taking into account the possible evolution of the orbital parameters, as determined by mass transfer between the components and by mass ejection from the system during episodes of Roche lobe overflow. We consider that the WD gains angular momentum due to accretion and we followed the evolution of the angular velocity profile as determined by angular momentum transport via convection and rotation-induced instabilities.
Results. As the donor H-rich envelope is transferred, the WD experiences recurrent very strong H-flashes triggering Roche lobe overflow episodes during which the entirety of the accreted matter is lost from the system. Due to mixing of chemicals by rotation-induced instabilities during the accretion phase, H-flashes occur inside the original WD. Hence, pulse by pulse, the mass of the accretor is reduced down to 0.7453 M⊙. Afterwards, when He-rich matter is transferred, He detonation does not occur in the rotating WD, which undergoes six very strong He-flashes and subsequent mass-loss episodes. Also in this case, due to rotation-induced mixing of the accreted layers with the underlying core, the WD is eroded. Later, as the mass-transfer rate from the donor decreases, a massive He buffer is piled up onto the accretor, which ends its life as a cooling WD.
Conclusions. The binary system PTF J2238+743015.1 and all other binary systems with components of similar masses and similar orbital parameters are not good candidates as thermonuclear explosion progenitors.
Relationship between TIGRE solar S-index and USET Ca II K full disk images
Authors: Vanden Broeck G. , Bechet S. , Clette F. , Rauw G. , Schröder K.-P. , Mittag M. 
Published: June 2024

Context. Full disk observations of the solar chromosphere in the Ca II K line represent a valuable dataset for studies of solar magnetic activity. The well known S-index is widely used to investigate the magnetic activity of stars, however, its connection to the coverage of stellar magnetic structure is still poorly understood.
Aims. We use the archives of full disk Ca II K images taken by the Royal Observatory of Belgium with the Uccle Solar Equatorial Table (USET) to derive the area fraction of the brightest chromospheric structures over the last decade. These data have allowed us to study the end of the solar cycle 24 and the beginning of the solar cycle 25. Our aim is to compare this dataset with the solar S-index from the Telescopio Internacional de Guanajuato Robotico Espectroscopico (TIGRE) lunar spectroscopy to analyze the relationship between a disk coverage index and an integrated spectrum. We also searched for periodic modulations in our two datasets to detect the solar rotation period.
Methods. We used more than 2700 days of observations since the beginning of the Ca II K observations with USET in July 2012. We performed a calibration of the images (re-centering and center-to-limb variation correction). The brightest regions of the solar surface (plages and enhanced network) were then segmented using an algorithm based on an intensity threshold. We computed the area fraction over the solar disk and compared it with the S-index from TIGRE. For the detection of periodic modulations, we applied a discrete Fourier power spectrum method to both datasets.
Results. A tight linear relationship was found between the USET area fraction and the TIGRE S-index, with an improved correlation obtained in the low-activity regime by considering the enhanced network. In both time series, we detected the modulation caused by the rotation of bright structures on the solar disk. However, this detection is constrained in the case of TIGRE due to its observation strategy.
Conclusions. We studied the correlation between the disk coverage with chromospheric structures and the variability of the S-index on an overlapping period of ten years. We concluded that the disk coverage index is a good proxy for the S-index and will be useful in future studies of the magnetic activity of solar-type stars. The USET area fraction dataset is most appropriate for evaluating the solar rotation period and will be used in future works to analyze the impact of the inclination of the stellar rotation axis on the detectability of such periodic modulations in solar-type stars.
Coronal energy release by MHD avalanches
Authors: Cozzo G. , Reid J. , Pagano P. , Reale F. , Testa P. , Hood A. W. , Argiroffi C. , Petralia A. , Alaimo E. , D’Anca F. , Sciortino L. , Todaro M. , Lo Cicero U. , Barbera M. , de Pontieu B. , Martinez-Sykora J. 
Published: June 2024

Context. Magnetohydrodynamic (MHD) instabilities, such as the kink instability, can trigger the chaotic fragmentation of a twisted magnetic flux tube into small-scale current sheets that dissipate as aperiodic impulsive heating events. In turn, the instability could propagate as an avalanche to nearby flux tubes and lead to a nanoflare storm. Our previous work was devoted to related 3D MHD numerical modeling, which included a stratified atmosphere from the solar chromosphere to the corona, tapering magnetic field, and solar gravity for curved loops with the thermal structure modelled by plasma thermal conduction, along with optically thin radiation and anomalous resistivity for 50 Mm flux tubes.
Aims. Using 3D MHD modeling, this work addresses predictions for the extreme-ultraviolet (EUV) imaging spectroscopy of such structure and evolution of a loop, with an average temperature of 2–2.5 MK in the solar corona. We set a particular focus on the forthcoming MUSE mission, as derived from the 3D MHD modeling.
Methods. From the output of the numerical simulations, we synthesized the intensities, Doppler shifts, and non-thermal line broadening in 3 EUV spectral lines in the MUSE passbands: Fe IX 171 Å, Fe XV 284 Å, and Fe XIX 108 Å, emitted by ∼1 MK, ∼2 MK, and ∼10 MK plasma, respectively. These data were detectable by MUSE, according to the MUSE expected pixel size, temporal resolution, and temperature response functions. We provide maps showing different view angles (front and top) and realistic spectra. Finally, we discuss the relevant evolutionary processes from the perspective of possible observations.
Reults. We find that the MUSE observations might be able to detect the fine structure determined by tube fragmentation. In particular, the Fe IX line is mostly emitted at the loop footpoints, where we might be able to track the motions that drive the magnetic stressing and detect the upward motion of evaporating plasma from the chromosphere. In Fe XV, we might see the bulk of the loop with increasing intensity, with alternating filamentary Doppler and non-thermal components in the front view, along with more defined spots in the topward view. The Fe XIX line is very faint within the chosen simulation parameters; thus, any transient brightening around the loop apex may possibly be emphasized by the folding of sheet-like structures, mainly at the boundary of unstable tubes.
Conclusions. In conclusion, we show that coronal loop observations with MUSE can pinpoint some crucial features of MHD-modeled ignition processes, such as the related dynamics, helping to identify the heating processes.
57Co-Flächenquellen und 99mTc-Flächenphantome für die Qualitätssicherung in der Nuklearmedizin
Authors: Kühnel Christian , Seifert Philipp , Freesmeyer Martin 
Published: June 2024

Zusammenfassung
Ziel Die wöchentliche Qualitätssicherung in der nuklearmedizinischen Diagnostik umfasst die Verwendung von radioaktiven Quellen und Phantomen, um eine gleichbleibende Leistung von Gammakameras, insbesondere im Hinblick auf die Homogenitätsüberprüfung, zu gewährleisten. Faktoren wie Quellenauswahl, physikalische Bedingungen, Strahlenbelastung und wirtschaftliche Überlegungen beeinflussen diesen Prozess. Diese Studie berichtet über die Verwendung von Flächenquellen und -phantomen zur Qualitätssicherung und erörtert die Vor- und Nachteile im klinischen Kontext, wobei die Notwendigkeit aktualisierter Untersuchungen aufgrund der seit den 1980er-Jahren veränderten Bedingungen hervorgehoben wird.
Methoden Eine 57Co-Floodquelle (ca. 740 MBq) und ein
mit 99mTc (ca. 600 MBq) befüllbares Flächenphantom wurden 1 Jahr lang wöchentlich
mit einer Doppelkopf-SPECT-Gammakamera auf Ausbeute/Empfindlichkeit gemessen. Für
Dosisleistungsmessungen in µSv/h H*(10) wurde ein kalibriertes Dosisleistungsmessgerät für
Messungen in 0, 1 und 2 m Entfernung verwendet.
Ergebnisse Die Kosten für die untersuchte 57Co-Quelle betrugen 3226,00 ± 1151,00 € (Median: 3310,00 €; Bereich: 2979,00–5996,00 €) über die letzten 10 Jahre je nach Lieferant. Ein zweijähriger Austauschzyklus war erforderlich. Die Kosten für die Flächenphantome einschließlich Ausrüstung liegen zwischen 3810,00 € und 8965,00 €. Die durchschnittlichen Kosten für einen Molybdän-Generator betrugen in den letzten 10 Jahren 1197,00 ± 144,00 € (Median: 1195,00 €; Spanne: 981,00–1547,00 €), mit einer durchschnittlichen jährlichen Wachstumsrate von 4 %. Die Handhabungszeit für die Homogenitätsüberprüfung mit einer 57Co-Flächenquelle betrug 60 ± 12 s (Median: 62 s; Bereich: 48–97 s). Die mittleren Dosisleistungen lagen dabei bei 282,3 µSv, 7,4 µSv und 2,7 µSv in 0, 1 bzw. 2 m Entfernung. Die Handhabungszeit für 99mTc-Flächenphantome lag im Mittel bei 451 ± 67 s (Median: 448 s; Bereich: 395–657 s), was zu 2,7 mSv, 91,8 µSv bzw. 37,5 µSv im Jahr führte.
Diskussion
57Co-Flächenquellen bieten eine schnellere Handhabung, eine geringere Dosisleistung im Zeitverlauf und einen geringeren Platzbedarf. Sie erfordern jedoch höhere Anschaffungs- und Entsorgungskosten, zusätzliches Zubehör und können Verunreinigungen aufweisen. Die Ergebnisse von Homogenitätsüberprüfungen oder der Bestimmung der Ausbeute sind dabei nicht auf andere Nuklide übertragbar. 99mTc-Flächenphantome hingegen sind lange verwendbar, verursachen kaum Folgekosten und entsprechen dem Leitnuklid der Mehrzahl der klinischen Untersuchungen. Die Messzeiten sind aufgrund der gleichbleibenden Aktivität vergleichbar und die optionale Verwendung von Umwälzpumpen sorgt für eine verbesserte Arbeitssicherheit. Demgegenüber bestehen jedoch potenziell höhere Expositionen des Personals, Herausforderungen bei der Reinigung und dem größeren Platzbedarf.
Management of Ruptured Intracranial Aneurysm with Deep Vein Thrombosis
Authors: Pandit Sneha , Dube Surya K. , Sokhal Suman , Chaturvedi Arvind 
Published: June 2024

AbstractDeep vein thrombosis (DVT) is a known complication of aneurysmal subarachnoid hemorrhage (aSAH), and anticoagulant therapy is crucial for its management. However, in case of a ruptured intracranial aneurysm in a patient of DVT, anticoagulant administration may lead to rebleeding. Anticoagulants are also associated with a risk of hematoma expansion. A systematic approach is required to weigh the risk and benefit ratio while managing such cases. We report the successful management of a 61-year-old female presenting with aSAH and associated DVT who had an intracranial vessel injury during intraoperative clipping of an aneurysm.
Neurological Effects of Stimulants and Hallucinogens
Authors: Hass Reece M. , Stitt Derek 
Published: June 2024

AbstractIn this article, we will discuss the history, pharmacodynamics, and neurotoxicity of psychostimulants and hallucinogens. The drugs discussed are widely used and have characteristic toxidromes and potential for neurological injuries with which the practicing clinician should be familiar. Psychostimulants are a class of drugs that includes cocaine, methamphetamine/amphetamines, and cathinones, among others, which produce a crescendoing euphoric high. Seizures, ischemic and hemorrhagic strokes, rhabdomyolysis, and a variety of movement disorders are commonly encountered in this class. Hallucinogens encompass a broad class of drugs, in which the user experiences hallucinations, altered sensorium, distorted perception, and cognitive dysfunction. The experience can be unpredictable and dysphoric, creating a profound sense of anxiety and panic in some cases. Recognizing the associated neurotoxicities and understanding the appropriate management is critical in caring for these patient populations. Several of these agents are not detectable by standard clinical laboratory analysis, making identification and diagnosis an even greater challenge.
Substance Use Disorder Treatment: Opportunities for Interdisciplinary Collaboration in Neurology and Beyond
Authors: Stoller Kenneth B. 
Published: June 2024

AbstractDriving the overdose epidemic, a significant proportion of adult and adolescent patients seen in neurology practice and hospital settings has substance use disorder. Fortunately, there are effective treatments available, in particular for opioid addiction. Some elements of treatment can be delivered directly in medical office-based settings, while others are best provided from within specialized addiction treatment facilities. In this article, we review the nature of substance use disorders, and the various treatment approaches that can be utilized to stabilize patients and facilitate their building a strong recovery foundation. Some interventions discussed may be directly provided by a physician identifying the disorder, while others involve collaboration with specialized addiction treatment centers and recovery support entities.
Idiopathic Hemiconvulsion Hemiplegia Epilepsy in an Eight-Year-Old Boy! Is It the Time to Revisit the HHE Definition?
Authors: Kamate Mahesh , Hattiholi Virupaxi 
Published: June 2024

AbstractIdiopathic hemiconvulsion hemiplegia epilepsy (IHHE) syndrome is characterized by the combination of unilateral convulsive status epilepticus, mainly clonic, followed by transient or permanent ipsilateral hemiplegia. It occurs in infants during the course of a nonspecific febrile illness, mainly in the first 2 years of life and in any case before the age of 4 years. Most studies have mentioned that disease occurs in children younger than 4 years. The exact cause of unilateral involvement is not clear. Occurrence of this condition beyond 4 years of age has rarely been described. We report here a previously healthy 8-year-old boy who presented with right hemiclonic seizures for almost 2 weeks occurring along with nonspecific viral illness. He had residual right hemiparesis and his magnetic resonance imaging (MRI) of the brain showed left hemispheric cortical edema with diffusion restriction. The workup for neuroinfections, mitochondriopathy, and MR angiography was negative. The child improved with injection methyl prednisolone pulse therapy along with multiple intravenous and oral antiseizure medications. This case report suggests that IHHE can also occur beyond 4 years of age, and there is a need to revise the diagnostic criteria of IHHE.
The reduction of Netspeak in Mandarin computer-mediated communication: a least effort motivation at the utterance level
Authors: Zhou Yong , Wu Yicheng 
Published: June 2024

AbstractThis article addresses the phenomenon of Netspeak reductions with special reference to Mandarin computer-mediated communication. A tentative classification of Chinese Netspeak reductions is first provided, namely, two-, three-, or four-character reductions occurring at both the lexical and the syntactic levels and other atypical reductions. It is then proposed that Zipf’s Principle of Least Effort, which usually works at the lexical level, can work as well at the utterance level and can account for the increasing number of Netspeak reductions in daily communication, that is, the frequency of using Netspeak reduction determines its vitality and distribution.
Navigating the uncertainty: the impact of a student-centered final year project allocation mechanism on student performance
Authors: Yuan Hang , Yuan Wenwen , Duan Sixuan , Yong Ruiqi , Jiao Keran , Wei Yan , Leach Mark , Li Na , Zhang Xiaojun , Lim Eng Gee , Song Pengfei 
Published: June 2024

AbstractThe Final Year Project (FYP) is one of the most important courses for every undergraduate student, and the effective operation of the FYPs in higher education still faces challenges, such as uneven resource distribution and limited efficiency. This study reports a mixed-methods approach to study the impact of a student-centered FYP allocation mechanism on student performance. This research aims to investigate how aligning students’ FYP choices with their interests can inspire motivation and enhance academic performance. More importantly, this mechanism improves students’ academic resilience, enabling them to navigate unexpected contextual factors. The study’s findings take into account various aspects, including student satisfaction with the allocation process, future improvement methods, and the relationship between interest and context. The outcomes observed in this study support our hypotheses, indicating the improvements in students’ academic performance as well as the pass and completion rates. Moreover, this research contributes to ‘resilience theory’ by exploring students’ adaptability to contextual changes and their enhancement of academic resilience. This study proposes recommendations for cultivating a dynamic student-centered classroom environment. Future work could pay attention to addressing the limitations of this study, exploring other factors influencing FYP allocation, and integrating more quantitative measures for a comprehensive assessment of its impact.
Violent conflict and multinational enterprises: identifying key frontiers in international business policy research
Authors: Liu Chang , Eden Lorraine , Li Dan 
Published: June 2024

AbstractViolent conflicts are events that involve the purposeful use of violence by state and/or non-state actor(s) to achieve political objectives, which result in disruptions to the institutional environment where actors such as civil society and multinational enterprises (MNEs) are situated. Examples of violent conflicts include civil and interstate wars and terrorist attacks. Violent conflicts typically have multiple, often devastating consequences that pose difficult policy challenges for governments and MNEs. This perspective offers an international business (IB) research and policy agenda to advance our understanding of the linkages between violent conflict and MNEs, focusing on three IB research and policy frontiers: the mechanisms through which MNEs are exposed to violent conflicts globally, MNE strategies and violent conflicts, and the interplay between MNEs and violent conflict environments. We also discuss appropriate datasets and research methods for studying MNEs and violent conflict.