bluuebunny/crossref_metadata_2025_split huggingface dataset:
KRATOS: A large suite of N-body simulations to interpret the stellar kinematics of LMC-like discs
Authors: Jiménez-Arranz Ó , Roca-Fàbrega S. , Romero-Gómez M. , Luri X. , Bernet M. , McMillan P. J. , Chemin L. 
Published: April 2024

Context. The Large and Small Magellanic Clouds (LMC and SMC, respectively) are the brightest satellites of the Milky Way (MW), and for the last thousand million years they have been interacting with one another. As observations only provide a static picture of the entire process, numerical simulations are used to interpret the present-day observational properties of these kinds of systems, and most of them have been focused on attempting to recreate the neutral gas distribution and characteristics through hydrodynamical simulations.
Aims. We present KRATOS, a comprehensive suite of 28 open-access pure N-body simulations of isolated and interacting LMC-like galaxies designed for studying the formation of substructures in their discs after interaction with an SMC-mass galaxy. The primary objective of this paper is to provide theoretical models that help us to interpret the formation of general structures in an LMC-like galaxy under various tidal interaction scenarios. This is the first paper of a series dedicated to the analysis of this complex interaction.
Methods. Simulations are grouped into 11 sets of up to three configurations, with each set containing (1) a control model of an isolated LMC-like galaxy; (2) a model that contains the interaction with an SMC-mass galaxy, and (3) a model where both an SMC-mass and a MW-mass galaxy may interact with the LMC-like galaxy (the most realistic model). In each simulation, we analysed the orbital history between the three galaxies and examined the morphological and kinematic features of the LMC-like disc galaxy throughout the interaction. This includes investigating the disc scale height and velocity maps. When a bar was found to develop, we characterised its strength, length, off-centredness, and pattern speed.
Results. The diverse outcomes found in the KRATOS simulations, including the presence of bars, warped discs, and various spiral arm shapes, demonstrate the opportunities they offer to explore a range of LMC-like galaxy morphologies. These morphologies directly correspond to distinct disc kinematic maps, making them well-suited for a first-order interpretation of the LMC’s kinematic maps. From the simulations, we note that tidal interactions can: boost the disc scale height; both destroy and create bars; and naturally explain the off-centre stellar bars. The bar length and pattern speed of long-lived bars are not appreciably altered by the interaction.
Conclusions. The high spatial, temporal, and mass resolution used in the KRATOS simulations has been shown to be appropriate for the purpose of interpreting the internal kinematics of LMC-like discs, as evidenced by the first scientific results presented in this work.
MINDS: JWST/NIRCam imaging of the protoplanetary disk PDS 70
Authors: Christiaens V. , Samland M. , Henning Th. , Portilla-Revelo B. , Perotti G. , Matthews E. , Absil O. , Decin L. , Kamp I. , Boccaletti A. , Tabone B. , Marleau G.-D. , van Dishoeck E. F. , Güdel M. , Lagage P.-O. , Barrado D. , Caratti o Garatti A. , Glauser A. M. , Olofsson G. , Ray T. P. , Scheithauer S. , Vandenbussche B. , Waters L. B. F. M. , Arabhavi A. M. , Grant S. L. , Jang H. , Kanwar J. , Schreiber J. , Schwarz K. , Temmink M. , Östlin G. 
Published: April 2024

Context. Two protoplanets have recently been discovered within the PDS 70 protoplanetary disk. JWST/NIRCam offers a unique opportunity to characterize them and their birth environment at wavelengths that are difficult to access from the ground.
Aims. We image the circumstellar environment of PDS 70 at 1.87 μm and 4.83 μm, assess the presence of Pa-α emission due to accretion onto the protoplanets, and probe any IR excess indicative of heated circumplanetary material.
Methods. We obtained noncoronagraphic JWST/NIRCam images of PDS 70 within the MIRI mid-INfrared Disk Survey (MINDS) program. We leveraged the Vortex Image Processing (VIP) package for data reduction, and we developed dedicated routines for optimal stellar point spread function subtraction, unbiased imaging of the disk, and protoplanet flux measurement in this type of dataset. A radiative transfer model of the disk was used to separate the contributions from the disk and the protoplanets.
Results. We redetect both protoplanets and identify extended emission after subtracting a disk model, including a large-scale spiral-like feature. We interpret its signal in the direct vicinity of planet c as tracing the accretion stream that feeds its circumplanetary disk, while the outer part of the feature may rather reflect asymmetric illumination of the outer disk. We also report a bright signal that is consistent with a previously proposed protoplanet candidate enshrouded in dust near the 1:2:4 mean-motion resonance with planets b and c. The 1.87 μm flux of planet b is consistent with atmospheric model predictions, but the flux of planet c is not. We discuss potential origins for this discrepancy, including significant Pa-α line emission. The 4.83 μm fluxes of planets b and c suggest enshrouding dust or heated CO emission from their circumplanetary environment.
Conclusions. The use of image-processing methods that are optimized for extended disk signals on high-sensitivity and high-stability from JWST can uniquely identify signatures of planet–disk interactions and enable accurate photometry of protoplanets at wavelengths that are difficult to probe from the ground. Our results indicate that more protoplanets can be identified and characterized in other JWST datasets.
Cepheids with giant companions
Authors: Pilecki Bogumił , Thompson Ian B. , Espinoza-Arancibia Felipe , Hajdu Gergely , Gieren Wolfgang , Taormina Mónica , Pietrzyński Grzegorz , Narloch Weronika , Bono Giuseppe , Gallenne Alexandre , Kervella Pierre , Wielgórski Piotr , Zgirski Bartłomiej , Graczyk Dariusz , Karczmarek Paulina , Evans Nancy R. 
Published: April 2024

Context. Binary Cepheids with giant companions are crucial for studying the physical properties of Cepheid variables, in particular providing the best means to measure their masses. Systems composed of two Cepheids are even more important, but to date, only one such system has been identified, in the Large Magellanic Cloud (LMC).
Aims. Our current aim is to increase the number of these systems known tenfold and to provide their basic characteristics. The final goal is to obtain the physical properties of the component Cepheids, including their masses and radii, and to learn about their evolution in the multiple systems, also revealing their origin.
Methods. We started a spectroscopic monitoring campaign of nine unresolved pairs of Cepheids from the OGLE catalog to check if they are gravitationally bound. Two of these so-called double Cepheids are located in the LMC, five are in the Small Magellanic Cloud (SMC), and two are in the Milky Way (MW).
Results. We report a spectroscopic detection of the binarity of all nine of these double Cepheids with orbital periods ranging from 2 to 18 years. This increases the number of known binary double (BIND) Cepheids from 1 to 10 and triples the number of all confirmed double-lined binary (SB2) Cepheids. For five BIND Cepheids, the disentangled pulsational light curves of the components show anti-correlated phase shifts due to orbital motion. We show the first empirical evidence that typical period–luminosity relations (PLRs) are rather binary Cepheid PLRs, as they include light of the companion.
Conclusions. The statistics of pulsation period ratios of BIND Cepheids do not agree with those expected for pairs of Cepheids of the same age. These ratios together with the determined mass ratios far from unity suggest a merger origin of at least one component for about half of the systems. The SMC and MW objects are the first found in SB2 systems composed of giants in their host galaxies. The Milky Way BIND Cepheids are also the closest such systems, being located at about 11 and 26 kpc.
Ensemble power spectral density of SDSS quasars in UV/optical bands
Authors: Petrecca V. , Papadakis I. E. , Paolillo M. , De Cicco D. , Bauer F. E. 
Published: April 2024

Context. Quasar variability has proven to be a powerful tool to constrain the properties of their inner engine and the accretion process onto supermassive black holes. Correlations between UV/optical variability and physical properties have been long studied with a plethora of different approaches and time-domain surveys, although the detailed picture is not yet clear.
Aims. We analysed archival data from the SDSS Stripe-82 region to study how the quasar power spectral density (PSD) depends on the black hole mass, bolometric luminosity, accretion rate, redshift, and rest-frame wavelength. We developed a model-independent analysis framework that could be easily applied to upcoming large surveys such as the Legacy Survey of Space and Time (LSST).
Methods. We used light curves of 8042 spectroscopically confirmed quasars, observed in at least six yearly seasons in five filters ugriz. We split the sample into bins of similar physical properties containing at least 50 sources, and we measured the ensemble PSD in each of them.
Results. We find that a simple power law is a good fit to the power spectra in the frequency range explored. Variability does not depend on the redshift at a fixed wavelength. Instead, both PSD amplitude and slope depend on the black hole mass, accretion rate, and rest-frame wavelength. We provide scaling relations to model the observed variability as a function of the physical properties, and discuss the possibility of a universal PSD shape for all quasars, where frequencies scale with the black hole mass, while normalization and slope(s) are fixed (at any given wavelength and accretion rate).
Superdiffusion of energetic particles at shocks: A fractional diffusion and Lévy flight model of spatial transport
Authors: Effenberger Frederic , Aerdker Sophie , Merten Lukas , Fichtner Horst 
Published: April 2024

Context. The observed power laws in space and time profiles of energetic particles in the heliosphere can be the result of an underlying superdiffusive transport behavior. Such anomalous, non-Gaussian transport regimes can arise, for example, as a consequence of intermittent structures in the solar wind. Non-diffusive transport regimes may also play a critical role in other astrophysical environments such as supernova remnant shocks.
Aims. To clarify the role of superdiffusion in the transport of particles near shocks, we study the solutions of a fractional diffusion-advection equation to investigate this issue. A fractional generalization of the Laplace operator, the Riesz derivative, provides a model of superdiffusive propagation.
Methods. We obtained numerical solutions to the fractional transport equation by means of pseudo-particle trajectories solving the associated stochastic differential equation driven by a symmetric, stable Lévy motion.
Results. The expected power law profiles of particles upstream of the plasma shock, where particles are injected, can be reproduced with this approach. The method provides a full, time-dependent solution of the fractional diffusion-advection equation.
Conclusions. The developed models enable a quantitative comparison to energetic particle properties based on a comprehensive, superdiffusive transport equation and allow for an application in a number of scenarios in astrophysics and space science.
Unveiling very young O stars
Authors: Roman-Lopes A. 
Published: April 2024

Context. O-type stars are known to significantly contribute to both the dynamics and evolution of galaxies. Massive and luminous, they probably control and regulate the galaxies star formation rates. The stellar feedback generated by such cosmic beasts can strongly affect the local star formation rate, with effects in the current (and future) generations of low and intermediate mass stars, and possibly also in the disruption process of the galaxies’ giant gas reservoirs.
Aims. For this work I performed a redetermination of the spectral types and effective temperatures of the Galactic O-type stars MSP182, MSP183, MSP199, VPHAS-01338, and VPHAS-01273.
Methods. From a careful examination of the spectral features present in the blue optical spectral region, it was possible to identify several nitrogen lines usually only seen in the blue optical spectra of O2–O3 stars. From the nitrogen ionic equivalent width ratios measured in the spectra of MSP182, MSP183, MSP199, VPHAS-01338, and VPHAS-01273, and in those of standard stars of the O2–O4 spectral types, earlier spectral types and hotter effective temperature values were derived.
Results. Two O2V((f*))z, together with three new O3 V stars are now firmly identified in the Westerlund 2 region. Besides RFS1 in NGC 3603, the O2 V stars found in Westerlund 2 are the only other exemplars known to date in the Milky Way. From the nitrogen equivalent width line ratios measured in the spectra of standard stars of the O2–O4 spectral types, linear relations between the N IVλ4058/N IIIλ4640 ratio and the effective temperature in the 47 000–51 000 K range were derived. Based on my spectroscopic analysis of the science targets and the use of a HRD, a mean heliocentric distance of 5 kpc to Westerlund 2 was computed, a result that is in line with the mean heliocentric distance of 5.3 ± 1.5 kpc obtained from the associated Gaia DR3 parallaxes and distances.
Conclusions. The Westerlund 2 massive stars studied in this work probably share a common evolutionary process that might be representative of the evolutionary ages of a large fraction of the cluster’s O-type stellar population, which seems to be much younger than 1 Myr.
Liability-driven investment for pension funds: stochastic optimization with real assets
Authors: Jang Chul , Clare Andrew , Owadally Iqbal 
Published: April 2024

AbstractUsing a multi-stage stochastic programming method, we suggest an optimal liability-driven investment (LDI) strategy for a closed defined-benefit pension fund including real assets. The objective is to jointly optimize contribution, funding ratio, and buyout cost, subject to a constraint on downside risk in terms of expected shortfall of assets relative to liabilities. Over a 10-year planning horizon, the optimal LDI strategy with a key-rate duration-matching bond portfolio outperforms the corresponding strategy with a duration-convexity matching bond portfolio as well as a strategy with an aggregate bond index-tracking portfolio. When real assets are introduced, the optimal LDI strategy includes significant investment in infrastructure and real estate, illiquidity notwithstanding. Nevertheless, delays in sales of real assets induced by illiquidity can increase downside risk.
In the fourth person singular: pragmatism, anarchism, and the earth
Authors: Savransky Martin 
Published: April 2024

AbstractNothing has done more to cement William James’s reputation than his unrepentant individualism. In a present marked by the challenge of imagining modes of transformative action worthy of our planetary travails, James’s individualism appears dated, unworthy of the present. Yet such judgement neglects its pragmatic dimension, as well as its political connections to James’s anarchistic pluralism. Situating anarchism at the centre of James’s vision, this article argues that his defence of individuals constitutes no ontological postulate but forms part of a speculative theory of change. Rather than apologia for individual heroism, James’s individualism is better understood in the impersonal voice of the “fourth person singular:” individual lives matter not as originary sources of heroic action but as zones of divergence through which terrestrial forces of mutation and metamorphosis pass. Revisiting connections between James’s individualism, pragmatism, and anarchism, the article offers a radical reappraisal of James’s thought as a vital method for intensifying unruly forces of transformation on an earth unstable and unsafe.
Magnetic anisotropy driven by ligand in 4d transition-metal oxide SrRuO3
Authors: Wakabayashi Yuki K. , Kobayashi Masaki , Seki Yuichi , Kotani Yoshinori , Ohkochi Takuo , Yamagami Kohei , Kitamura Miho , Taniyasu Yoshitaka , Krockenberger Yoshiharu , Yamamoto Hideki 
Published: April 2024

The origin of magnetic anisotropy in magnetic compounds is a longstanding issue in materials science, and nonmagnetic ligand ions are considered to contribute little to magnetic anisotropy. Here, we introduce the concept of ligand-driven magnetic anisotropy in a complex transition-metal oxide. We conducted x-ray magnetic circular dichroism spectroscopies at the Ru and O edges in the 4d ferromagnetic metal SrRuO3. Systematic variation of the sample thickness in the range of ≤10 nm allowed us to control the localization of Ru 4d t2g states, which affects the magnetic coupling between the Ru and O ions. We observe that the orbital magnetic moment of the ligand O 2p orbitals induced through the charge transfer to the Ru 4d t2g states becomes anisotropic first, and the anisotropic magnetic moment of Ru and, therefore, the entire system is induced via magnetic coupling between Ru 4d and O 2p orbitals.
Bacterial vaginosis after menopause: factors associated and women’s experiences: a cross-sectional study of Australian postmenopausal women
Authors: Stewart Linde L. , Vodstrcil Lenka A. , Coombe Jacqueline , Bradshaw Catriona S. , Hocking Jane S. 
Published: April 2024

Background Bacterial vaginosis (BV) is the most common cause of vaginal discharge in reproductive age women; however, little is known about it after menopause. We aimed to learn more about BV in Australian postmenopausal women. Methods We conducted an online survey (July–September 2021). Participants were recruited via social media and professional networks and asked about demographic characteristics, sexual history and BV experiences. Outcomes of interest were the proportion who had heard of BV, had BV ever, or had BV after menopause. Factors associated with these outcomes were assessed using logistic regression. Results Of 906 participants, 83% were included in the analysis. Overall, 37.9% had heard of BV, 11.0% reported having a BV diagnosis ever, 6.3% reported having a BV diagnosis after menopause and 4.4% reported having a BV diagnosis only after menopause. Multivariable analysis found that among all women the odds of having a BV diagnosis after menopause were increased for those who had BV before menopause, had douched in the past 12 months, or had a previous STI diagnosis. Among those in a sexual relationship, a BV diagnosis after menopause was associated with a BV diagnosis before menopause, or being in a sexual relationship of 5 years or less in duration. About half who reported BV after menopause described recurrences, distress, and a detrimental effect on sexual relationships. Conclusions BV in postmenopausal women is associated with sexual activity, and impacts negatively on their lives. Research into BV should not be limited to reproductive age women.
An estimate of the marginal annual economic contribution of wild-pig hunting in Texas
Authors: McKee Sophie C. , Carlisle Keith M. , Tomeček John , Shwiff Stephanie A. , Connally Rachael , Frank Maureen , Bodenchuk Mike , Didero Nicole 
Published: April 2024

Context Wild-pig hunting is a culturally significant recreational and commercial activity in Texas, but the overall impacts are contested. Except for one 1980s study, there has been no research to formally quantify any economic benefits of wild-pig hunting in Texas, which is an important component for weighing the costs and benefits of wild-pig presence in the state. Aims and methods To fill that research gap, we surveyed a sample of resident and non-resident 2018–2019 hunting-license holders in Texas about various topics related to their wild-pig hunting activities, including expenditures. Key results On the basis of the 37,317 responses received, we estimated that the marginal annual direct economic benefit of wild-pig hunting to the Texas economy ranges between US$68.5 million and US$188.0 million (2022 dollar values). Given that we were not able to distinguish whether purchases were made in or out of state for expenses provided, we believe this range is an upper estimate. Conclusion and implications Although hunting is an important consideration in the discussion of wild-pig management, this estimate is dwarfed by the estimated total damage costs associated with wild pigs in Texas.
Quantitative study of random walk parameters in node2vec model
Authors: Li Yuanbiao , Yang Bo 
Published: April 2024

Abstract
In this paper, the Monte Carlo simulation method is used to investigate a generalized random walk model based on node2vec which is a popular algorithm in network embedding and has been widely applied in various domains such as link prediction, node classification, recommendation systems, etc. The aim is to quantitatively study the impact of the random walk parameters(including the number of walks per initial node r, the length of each walk l, the return parameter α, the common neighbor parameter β, and the outgoing parameter γ) on the embedding results. Specifically, the cross entropy is utilized as an observation to compare the difference between the frequency of nodes after random walks and the normalized degree sequence of nodes. The results show that the clustering coefficient significantly impacts the cross entropy. For networks with high clustering coefficient, the value of β should closely approximate that of γ, whereas for networks with low clustering coefficient, the value of β should be significantly smaller than that of γ. The value of α should be less than or equal to the minimum values between β and γ. Finally, the embedding effects of different random walk parameters are tested using node classification and link prediction tasks in real-world networks, and the results indicate that cross entropy can provide guidance for obtaining high-quality node embedding.
Influence of cladding tube structure on transmission characteristics of negative curvature terahertz fiber
Authors: Yan Dexian , Yuan Ziwei , Qiu Jianzhong , Li Xiangjun 
Published: April 2024

Abstract
A novel type of polarization negative curvature terahertz fiber has been designed, which has a cladding region composed of two long semi-circular cladding tubes in the horizontal direction and four long semi-elliptical cladding tubes in the oblique direction. The optimal fiber dimensions are determined to investigate the internal relationship between polarization characteristics and fiber cladding structure. The transmission performances of the negative curvature fiber are investigated by varying the thickness of fiber cladding tubes and adjusting the structural characteristics of cladding tubes in different directions. Relatively good transmission performances can be obtained with a cladding tube thickness of 80 μm. The birefringence can be stably maintained at the order of 10−4, and the confinement loss of the x-polarized mode at 2.55 THz is 0.036 dB cm−1. Moreover, the dispersion coefficient of the two polarized modes is stable between ±0.6 ps (THz·cm)−1 in the 2.3–2.6 THz band. The bent performance of the designed fiber at 2.52 THz is also discussed. The results show that the fiber has low bending sensitivity, and can still maintain excellent birefringence and low confinement loss in the bending state. For the y polarization, the birefringence can be basically stabilized at the order of 10−4 within a bending radius of 10–60 cm.
New quantum LDPC codes based on Euclidean Geometry
Authors: Feng Ya’nan , Tang Chuchen , Bai Chenming 
Published: April 2024

Abstract
With the advancements in quantum error correction technique, quantum low density parity check (QLDPC) codes have emerged as a promising area in the field of quantum error correction. This paper focuses on the requirement of QLDPC codes based on points excluding the origin, and lines that do not pass through the origin of Euclidean Geometry. It also explores QLDPC codes based on all the points and lines. Finally, a series of simulation analyses are presented.