bluuebunny/crossref_metadata_2025_split huggingface dataset:
TT Arietis: New approach to the analysis of quasi-periodic oscillations
Authors: Vega-Manubens I. , Vogt N. , Lopera-Mejía A. , Aravena-Rojas G. , Rojas Lobos P. A. 
Published: October 2024

Context. TT Arietis (TT Ari) is a nova-like cataclysmic variable of the VY Scl subtype with light-curve variations on multiple timescales. In addition to the superhump modulation, quasi-periodic oscillations (QPOs) have been found.
Aims. Our aim is to determine the occurrence, strength, and variability of QPOs in TT Ari based on more complete data than in previous works.
Methods. The data were obtained during the high state of TT Ari in October 2012 by the MOST space telescope, covering a total of 361.2 hours of continuous observation. We searched for frequencies over subsets of time using a Fourier-like power spectrum and then added the frequencies together, forming groups.
Results. Our method has revealed QPOs that occur in ‘frequency groups’, which are events with a continuous oscillation of similar, constant or slowly variable frequency. We report a total of 160 frequency groups in the period range between 14 and 53 minutes (27 and 98 days−1), with two peaks in the power spectrum at 18.5 and 33.8 minutes (42.5 and 77.5 days−1). The duration of these frequency groups varies between 0.72 and 7.5 hours (average 2.8 hours) revealing between 3 and 18 complete cycles in the light curve. Most of them show significant frequency variations over the course of their duration. Sometimes two frequency groups occur simultaneously. An analysis with randomised data confirms that stochastic processes can only explain a fraction of the QPOs found. The occurrence of QPOs appears not to be related to the superhump phase.
Origin of the type III radiation observed near the Sun
Authors: Mozer F. S. , Agapitov O. , Bale S. D. , Goetz K. , Krasnoselskikh V. , Pulupa M. , Sauer K. , Voshchepynets A. 
Published: October 2024

Aims. We investigate processes associated with the generation of type III radiation using Parker Solar Probe measurements.
Methods. We measured the amplitudes and phase velocities of electric and magnetic fields and their associated plasma density fluctuations.
Results. 1. There are slow electrostatic waves near the Langmuir frequency and at as many as six harmonics, the number of which increases with the amplitude of the Langmuir wave. Their electrostatic nature is shown by measurements of the plasma density fluctuations. From these density fluctuations and the electric field magnitude, the k-value of the Langmuir wave is estimated to be 0.14 and kλd = 0.4. Even with the large uncertainty in this quantity (more than a factor of two), the phase velocity of the Langmuir wave was < 10 000 km/s. 2. The electromagnetic wave near the Langmuir frequency has a phase velocity lower than 50 000 km/s. 3. We cannot determine whether there are electromagnetic waves at the harmonics of the Langmuir frequency. If they existed, their magnetic field components would be below the noise level of the measurement. 4. The rapid (less than one millisecond) amplitude variations typical of the Langmuir wave and its harmonics are artifacts resulting from the addition of two waves, one of which has small frequency variations that arise because the wave travels through density irregularities. None of these results are expected in or consistent with the conventional model of the three-wave interaction of two counter-streaming Langmuir waves that coalesce to produce the type III wave. They are consistent with a new model in which electrostatic antenna waves are produced at the harmonics by radiation of the Langmuir wave, after which at least the first harmonic wave evolved through density irregularities such that its wave number decreased and it became the type III radiation.
AGN feeding along a one-armed spiral in NGC 4593
Authors: Kianfar K. , Andreani P. , Fernández-Ontiveros J. A. , Combes F. , Spinoglio L. , Hatziminaoglou E. , Ricci C. , Bewketu-Belete A. , Imanishi M. , Pereira-Santaella M. , Slater R. , Malheiro M. 
Published: October 2024

Context. We investigate active galactic nuclei (AGN) feeding through the molecular gas (CO(2−1) emission) properties of the local Seyfert 1 galaxy NGC 4593, using Atacama Large Millimeter Array (ALMA) observations and other multi-wavelength data.
Aims. Our study aims to understand the interplay between the AGN and the interstellar medium (ISM) in this galaxy, examining the role of the AGN in steering gas dynamics within its host galaxy, evaluating the energy injected into the ISM, and determining whether gas is inflowing or outflowing from the galaxy.
Methods. After reducing the ALMA CO(2−1) images, we employed two models, 3D-BAROLO and DISCFIT, to construct a disc model and fit its emission to the ALMA data. Additionally, we used photometric data to build a spectral energy distribution (SED) and apply the CIGALE code to derive key physical properties of the AGN and its host.
Results. Our analysis reveals a complex interplay within NGC 4593, including a clear rotational pattern, the influence of a non-axisymmetric bar potential, and a central molecular zone (CMZ)-like ring. We observe an outflow of CO(2−1) gas along the minor axis, at a distance of ∼220 pc from the nucleus. The total molecular gas mass is estimated to be 1 − 5 × 108 M⊙, with non-circular motions contributing 10%. Our SED analysis indicates an AGN fraction of 0.88 and a star formation rate (SFR) of 0.42 M⊙ yr−1.
Conclusions. These findings highlight the complex dynamics in the centre of NGC 4593, which are significantly influenced by the presence of the AGN. The overall physical properties of this system suggest that the AGN has a substantial impact on the evolution of NGC 4593.
Advanced classification of hot subdwarf binaries using artificial intelligence techniques and Gaia DR3 data
Authors: Viscasillas Vázquez C. , Solano E. , Ulla A. , Ambrosch M. , Álvarez M. A. , Manteiga M. , Magrini L. , Santoveña-Gómez R. , Dafonte C. , Pérez-Fernández E. , Aller A. , Drazdauskas A. , Mikolaitis Š. , Rodrigo C. 
Published: October 2024

Context. Hot subdwarf stars are compact blue evolved objects, burning helium in their cores surrounded by a tiny hydrogen envelope. In the Hertzsprung-Russell Diagram they are located by the blue end of the Horizontal Branch. Most models agree on a quite probable common envelope binary evolution scenario in the Red Giant phase. However, the current binarity rate for these objects is yet unsolved, but key, question in this field.
Aims. This study aims to develop a novel classification method for identifying hot subdwarf binaries within large datasets using Artificial Intelligence techniques and data from the third Gaia data release (GDR3). The results will be compared with those obtained previously using Virtual Observatory techniques on coincident samples.
Methods. The methods used for hot subdwarf binary classification include supervised and unsupervised machine learning techniques. Specifically, we have used Support Vector Machines (SVM) to classify 3084 hot subdwarf stars based on their colour-magnitude properties. Among these, 2815 objects have Gaia DR3 BP/RP spectra, which were classified using Self-Organizing Maps (SOM) and Convolutional Neural Networks (CNN). In order to ensure spectral quality, previously to SOM and CNN classification, our 2815 BP/RP set were pre-analysed with two different approaches: the cosine similarity technique and the Uniform Manifold Approximation and Projection (UMAP) technique. Additional analysis onto a golden sample of 88 well-defined objects, is also presented.
Results. The findings demonstrate a high agreement level (∼70–90%) with the classifications from the Virtual Observatory Sed Analyzer (VOSA) tool. This shows that the SVM, SOM, and CNN methods effectively classify sources with an accuracy comparable to human inspection or non-AI techniques. Notably, SVM in a radial basis function achieves 70.97% reproducibility for binary targets using photometry, and CNN reaches 84.94% for binary detection using spectroscopy. We also found that the single–binary differences are especially observable on the infrared flux in our Gaia DR3 BP/BR spectra, at wavelengths larger than ∼700 nm.
Conclusions. We find that all the methods used are in fairly good agreement and are particularly effective to discern between single and binary systems. The agreement is also consistent with the results previously obtained with VOSA. In global terms, considering all quality metrics, CNN is the method that provides the best accuracy. The methods also appear effective for detecting peculiarities in the spectra. While promising, challenges in dealing with uncertain compositions highlight the need for caution, suggesting further research is needed to refine techniques and enhance automated classification reliability, particularly for large-scale surveys.
Photometric properties of classical bulge and pseudo-bulge galaxies at 0.5 ≤ z < 1.0
Authors: Hu Jia , Cui Qifan , Wang Lan , Pei Wenxiang , Ge Junqiang 
Published: October 2024

Context. We compare the photometric properties and specific star formation rate (sSFR) of classical- and pseudo-bulge galaxies with M∗ ≥ 109.5 M⊙ at 0.5 ≤ z < 1.0, selected from all five CANDELS fields. We also compare these properties of bulge galaxies at lower redshift selected from MaNGA survey in previous work.
Aims. This paper aims to study the properties of galaxies with classical and pseudo-bulges at intermediate redshift, to compare the differences between different bulge types, and to understand the evolution of bulges with redshift.
Methods. Galaxies are classified into classical bulge and pseudo-bulge samples according to the Sérsic index n of the bulge component based on results of two-component decomposition of galaxies, as well as the position of bulges on the Kormendy diagram. For the 105 classical bulge and 86 pseudo-bulge galaxies selected, we compare their size, luminosity, and sSFR of various components.
Results. At a given stellar mass, most classical bulge galaxies have smaller effective radii, larger B/T, brighter and relatively larger bulges, and less active star formation than pseudo-bulge galaxies. In addition, the two types of galaxies have larger differences in sSFR at large radii than at the central region at both low- and mid-redshifts.
Conclusions. The differences between the properties of the two types of bulge galaxies are generally smaller at mid-redshift than at low-redshift, indicating that they are evolving to more distinct populations towards the local universe. Bulge type is correlated with the properties of their outer disks, and the correlation is already present at redshifts as high as 0.5 < z < 1.
Nuclear energy and international relations: the external strategy of Russia’s Rosatom
Authors: Siddi Marco , Silvan Kristiina 
Published: October 2024

AbstractThis article analyses the role of nuclear energy in global politics today through the perspective of three International Relations theories: realism, liberalism and dependency theory. It contends that concepts developed to investigate oil and gas geopolitics do not always apply to the nuclear sector due to its greater complexity. The supply chain for nuclear power involves different, interrelated stages—notably the provision of natural uranium, of enriched uranium, and the construction and servicing of nuclear reactors—which have distinct leading suppliers and relationships of dependence. We illustrate this through a case study of Russia’s state nuclear company Rosatom. Rosatom leads in the provision of enriched uranium and reactor construction. This enables Russia to deepen economic and political relations with Rosatom’s clients. Even after its attack on Ukraine, Russia has not ‘weaponized’ Rosatom’s international business. Its strategy focuses on consolidating its reputation as a trustworthy partner, especially in the Global South and China.
The temporalities of cultural transfer
Authors: Sandrock Kirsten 
Published: October 2024

Abstract
This chapter analyses forms and functions of cultural transfer in Robert Louis Stevenson’s Pacific travel
writings with a particular focus on the temporalities of cultural exchanges. It examines the multiple timeframes of cultural
transfer so as to open up a perspective on Stevenson’s works as negotiating not only the ambiguities of geographical but also
of time-based contact zones, where past, present and future meet. Such an exploration adds a temporal perspective to Mary
Louis Pratt’s term of the ‘contact zone’ insofar as it suggests that asymmetrical relationships cannot only arise out of
intercultural geographical spaces but can also result from inner-cultural encounters with different periods and times. Ghost
imagery and the narration of loss are part of the aesthetic repertoire Stevenson uses in his work to mediate the temporalities
of cultural contact zones. Together with other forms of cultural transfer, such as linguistic translation, the construal of
the traveller-narrator as intermediary figure and anthropological depictions of Pacific cultures, ghost images and tropes of
loss illustrate the complex chronotopical entanglements of cultural encounters that Stevenson negotiates in his Pacific
writings. Stevenson’s A Footnote to History (1892) and In
the South Seas (1896) offer rich resources for understanding the
temporal complexities of cultural transfer because, during his time in the Pacific, Stevenson was deeply occupied with the
multiple temporalities of cultures and cultural contact zones.
The narrative skills of Russian-Cypriot Greek children
Authors: Karpava Sviatlana 
Published: October 2024

Abstract
This study investigates the narrative skills of Russian-Cypriot Greek bilingual children, with a
focus on macro- and micro-structure, grammaticality, and disfluencies. The results show a correlation between the
rates of macro- and micro-structure measures, grammaticality, and disfluencies in the heritage language, Russian. Mode
of narration, age, and language proficiency affect the narrative production. The most prominent disfluency types are
repetitions, filled pauses, and lexical and grammatical revisions, which can be due to the activation of both
languages and cross-linguistic interference. The grammaticality analysis revealed that the most vulnerable domain for
bilingual children was in the functional categories. This research provides further evidence to Russian heritage
language research for early-stage language development, with a new societal majority language, Cypriot Greek.
EURAMET.EM.RF-S46 (EURAMET Project No 1538) EURAMET supplementary comparison on magnetic field strength measurements for frequencies up to 30 MHz
Authors: Şen Osman , Aslan Çaǧlar , Ulvr Michal , Pavlíček Tomáš , Baaske Kai , Weickert Franziska , Crotti Gabriella , Osiński Mateusz , AlMojaewel Saleh , Cedheim Mats , Pythoud Frédéric , Harmon Stuart 
Published: October 2024

Main text
The results of the supplementary comparison in the area of magnetic field probe calibration of the field strength are presented. This supplementary comparison has been discussed to organize a comparison on magnetic field strength measurements during the EURAMET TC-EM Subcommittee Radiofrequency and Microwave (SC-MW) meeting, including an EMC meeting, organized as a virtual (online) meeting on 20-21 April 2021. The comparison was conducted in accordance with the Technical Protocol of "Comparison of Magnetic Field Strength Measurements for Frequencies up to 30 MHz, EURAMET Project No 1538, EURAMET.EM.RF-S46", which was prepared by the TÜBİTAK UME and approved by the participants. The measurements started in January 2022 and were completed in May 2023. Measurement results reported by nine participants for magnetic field strength values were compared and degrees of equivalence are reported.
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
A simulation study for enhancing the performance of luminescent organic transistor using reduced voltage and hole blocking layer
Authors: Kumar Vijay , Madhu Charu 
Published: October 2024

Abstract
Eco-friendly and biodegradable technology forms the basis of organic electronics. A luminescent organic transistor (LOT) is a device created using this technology, which is capable of emission of light and acting as switch functions in a single unit. This research seeks to develop and model a nonplanar contact heterostructure-based LOT by employing the defect density of states (DOS) to accurately simulate the amorphous nature of organic semiconductors. This study evaluates two high-k dielectric materials, hafnium oxide (HfO2) and poly(vinylidene fluoride-trifluoroethylene)P(VDF-TrFe), to achieve low-voltage operation at (−10 V). Furthermore, this study investigated the influence of a hole blocking material, 1, 3, 5-Tris(3-pyridyl-3-phenyl)benzene(TmPyPB), on device performance. Simulations revealed p-channel transistor characteristics with a maximum source-drain current of (−1.6 mA) and an on–off current ratio exceeding 104 for HfO2, compared to (−0.75 mA) and approximately 104 for P(VDF-TrFe). The model also demonstrated exceptional electrical properties, including a peak hole mobility of (1.96 cm2 v−1 s−1), a threshold voltage

V

T

of (−0.85 V), and a sub-threshold voltage of 492 mV/dec in saturation. The recombination zone exhibited an electron concentration of 18.0 cm−3, a hole concentration of 19
.
3cm−3, and a Langevin recombination rate of 24.7 cm−3 s−1 near the drain electrode. This model serves as an ideal platform for testing newly developed molecules to enhance the performance of luminescent transistor.
Effects of Al doping on structural, optical, morphological, and low-concentration CO2 gas sensing properties of ZnO nanoparticles synthesized by sol-gel method
Authors: Mishra Manmohan , Kumar Mahendra 
Published: October 2024

Abstract
This work examines the morphological, structural, optical, and gas-sensing characteristics of ZnO thin films doped with Al that were created by the sol-gel spin coating technique. The thin films, doped with varying aluminum concentrations (0%, 2%, and 5%), were characterized using XRD, UV-visible spectroscopy, and FE-SEM to assess their crystallinity, band gap, and surface morphology. XRD analysis confirmed the incorporation of Al into the ZnO lattice without forming secondary phases, while UV-visible spectroscopy revealed an increase in transmittance and band gap with higher Al doping. FE-SEM images showed a transition from agglomerated grains to smoother surfaces with increased Al content. Gas sensing performance was evaluated using low-concentration CO2 as the target gas. The results demonstrated that Al doping significantly enhances the CO2 sensing response, with the 5% Al-doped ZnO exhibiting the optimal sensitivity due to increased carrier concentration and improved surface interaction. These findings suggest that Al-doped ZnO thin films are promising candidates for efficient CO2 gas sensors, combining enhanced structural and optical properties with superior gas sensing capabilities.
Photocatalysis, wettability and optical properties of N-doped Cu2O/CuO thin films for smart coating applications
Authors: Hassaballa S , Aljabri A , Mohamed S H , Bakry A M , El-Rahman A M Abd , Awad M A 
Published: October 2024

Abstract
Undoped and nitrogen (N)_doped Cu2O/CuO thin films were deposited via reactive DC magnetron sputtering. The deposition was carried out by sputtering the Cu targets under various Ar/N2/O2 gas flow ratios. The structural, optical, wettability, and photocatalytic performance of the deposited films were investigated. A simple cubic Cu2O crystallographic phase is observed for the undoped film, whereas mixed cubic Cu2O and monoclinic CuO phases (Cu2O/CuO) are observed for the N_doped films. EDAX revealed that as the N2 flow rate increased the amount of nitrogen incorporated into the film increased. The transmittance and reflectance are affected by the incorporation of nitrogen into the films. The transmittance values decreased with increasing N2 flow rate, whereas the reflectance values increased. Both the refractive index and extinction coefficient almost increased with increasing N2 flow rate. A noticeable optical band gap narrowing from 2.55 eV to 2.39 eV was detected upon increasing the N2 flow from 0.0 to 190 sccm. The photoluminescence spectrum of the undoped sample contains five distinct bands at 518, 612, 654, 714 and 825 nm. These five maxima are attributed to the radiative decay of bound and free excitons, and oxygen vacancies (VO) After nitrogen incorporation, the photoluminescence intensity decreases and then increases again with increasing N2 flow rate. A reduction in the water contact angle was observed with increasing N2 flow rate. Upon Vis-light illumination, the N_doped Cu2O/CuO films reached superhydrophilicity faster than the undoped film did. The photocatalytic performance of the deposited Cu2O/CuO films was strongly enhanced with a small amount of N doping. The deposited films are promising for self-cleaning and photocatalytic degradation of organic wastes.
Thermally-induced diffusion and structural phase transitions in Pt/Mn and Pt/Mn/Pt thin films
Authors: Voloshko Svitlana , Kruhlov Ivan , Pedan Roman , Garrido-Segovia María , Orlov Andrii , Dubikovskyi Oleksandr , García-Martín José Miguel , Kaidatzis Andreas , Vladymyrskyi Igor 
Published: October 2024

Abstract
We demonstrate the possibility of diffusion formation of the chemically ordered L1
0-MnPt phase through the vacuum annealing of Pt(24 nm)/Mn(20 nm) and Pt(12 nm)/Mn(20 nm)/Pt(12 nm) layered stacks at 400 °C for 30 min. For the bi-layered stack annealed at 400 °C, the effect of Pt atoms segregation at the film/substrate interface was detected, which remained after annealing even at higher temperatures (500 °C and 600 °C) and prevented the whole homogenization of the chemical composition through the film depth. By contrast, for the tri-layered stack annealed at 400 °C, the presence of the additional Pt bottom layer enabled to change the rate and mechanism of reactive diffusion, leading to homogeneous distribution of components and enhanced crystallinity of the ordered L1
0-MnPt phase compared to the bi-layered sample. An explanation of the obtained experimental data is provided based on the fundamentals of mass transfer theory and its quantitative parameters (e.g. activation energy and diffusion coefficients).
Exploring the inverse line-source scattering problem in dielectric cylinders with deep neural networks
Authors: Pallikarakis Nikolaos , Kalogeropoulos Andreas , Tsitsas Nikolaos L 
Published: October 2024

Abstract
This study presents a novel approach utilizing deep neural networks to address the inverse line-source scattering problem in dielectric cylinders. By employing Multi-layer Perceptron models, we intend to identify the number, positions, and strengths of hidden internal sources. This is performed by using single-frequency phased data, from limited measurements of real electric and real magnetic surface fields. Training data are generated by solving corresponding direct problems, using an exact solution representation. Through extended numerical experiments, we demonstrate the efficiency of our approach, including scenarios involving noise, reduced sample sizes, and fewer measurements. Additionally, we examine the empirical scaling laws governing model performance and conduct a local analysis to explore how our neural networks handle the inherent ill-posedness of the considered inverse problems.