bluuebunny/crossref_metadata_2025 huggingface dataset:
Breast cancer diagnosis using support vector machine optimized by improved quantum inspired grey wolf optimization
Authors: Bilal Anas , Imran Azhar , Baig Talha Imtiaz , Liu Xiaowen , Abouel Nasr Emad , Long Haixia
Published: May 2024

A prompt diagnosis of breast cancer in its earliest phases is necessary for effective treatment. While Computer-Aided Diagnosis systems play a crucial role in automated mammography image processing, interpretation, grading, and early detection of breast cancer, existing approaches face limitations in achieving optimal accuracy. This study addresses these limitations by hybridizing the improved quantum-inspired binary Grey Wolf Optimizer with the Support Vector Machines Radial Basis Function Kernel. This hybrid approach aims to enhance the accuracy of breast cancer classification by determining the optimal Support Vector Machine parameters. The motivation for this hybridization lies in the need for improved classification performance compared to existing optimizers such as Particle Swarm Optimization and Genetic Algorithm. Evaluate the efficacy of the proposed IQI-BGWO-SVM approach on the MIAS dataset, considering various metric parameters, including accuracy, sensitivity, and specificity. Furthermore, the application of IQI-BGWO-SVM for feature selection will be explored, and the results will be compared. Experimental findings demonstrate that the suggested IQI-BGWO-SVM technique outperforms state-of-the-art classification methods on the MIAS dataset, with a resulting mean accuracy, sensitivity, and specificity of 99.25%, 98.96%, and 100%, respectively, using a tenfold cross-validation datasets partition.
Classification performance assessment for imbalanced multiclass data
Authors: Aguilar-Ruiz Jesús S. , Michalak Marcin
Published: May 2024

The evaluation of diagnostic systems is pivotal for ensuring the deployment of high-quality solutions, especially given the pronounced context-sensitivity of certain systems, particularly in fields such as biomedicine. Of notable importance are predictive models where the target variable can encompass multiple values (multiclass), especially when these classes exhibit substantial frequency disparities (imbalance). In this study, we introduce the Imbalanced Multiclass Classification Performance (IMCP) curve, specifically designed for multiclass datasets (unlike the ROC curve), and characterized by its resilience to class distribution variations (in contrast to accuracy or F$$_\beta$$

β

-score). Moreover, the IMCP curve facilitates individual performance assessment for each class within the diagnostic system, shedding light on the confidence associated with each prediction—an aspect of particular significance in medical diagnosis. Empirical experiments conducted with real-world data in a multiclass context (involving 35 types of tumors) featuring a high level of imbalance demonstrate that both the IMCP curve and the area under the IMCP curve serve as excellent indicators of classification quality.
Superconductivity of thulium substituted clathrate hexahydrides at moderate pressure
Authors: Huang Hongyu , Deng Chao , Song Hao , Du Mingyang , Duan Defang , Liu Yanhui , Cui Tian
Published: May 2024

Due to the BCS theory, hydrogen, the lightest element, would be the prospect of room-temperature superconductor after metallization, but because of the difficulty of the hydrogen metallization, the theory about hydrogen pre-compression was proposed that the hydrogen-rich compounds could be a great option for the high Tc superconductors. The superior properties of TmH6, YbH6 and LuH6 indicated the magnificent potential of heavy rare earth elements for low-pressure stability. Here, we designed XTmH12 (X = Y, Yb, Lu, and La) to obtain higher Tc while maintaining low pressure stability. Most prominently, YbTmH12 can stabilize at a pressure of 60 GPa. Compared with binary TmH6 hydride, its Tc was increased to 48 K. The results provide an effective method for the rational design of moderate pressure stabilized hydride superconductors.
On-farm crop diversity, conservation, importance and value: a case study of landraces from Western Ghats of Karnataka, India
Authors: Puneeth G. M. , Gowthami Ravi , Katral Ashvinkumar , Laxmisha Kerekoppa Manjunatha , Vasudeva Ramesh , Singh Gyanendra Pratap , Archak Sunil
Published: May 2024

Landraces are important genetic resources that have a significant role in maintaining the long-term sustainability of traditional agro-ecosystems, food, nutrition, and livelihood security. In an effort to document landraces in the on-farm conservation context, Central Western Ghat region in India was surveyed. A total of 671 landraces belonging to 60 crops were recorded from 24 sites. The custodian farmers were found to conserve a variety of crops including vegetables, cereals and pulses, perennial fruits, spices, tuber and plantation crops. The survey indicated a difference in the prevalence of landraces across the sites. A significant difference with respect to the Shannon-diversity index, Gini-Simpson index, evenness, species richness, and abundance was observed among the different survey sites. Computation of a prevalence index indicated the need for immediate intervention in the form of collecting and ex situ conservation of landraces of some crops as a back-up to on-farm conservation. The study also identified the critical determinants of on-farm conservation, including (i) suitability to regional conditions, (ii) relevance in regional cuisine and local medicinal practices, (iii) cultural and traditional significance, and (iv) economic advantage. The information documented in this study is expected to promote the collection and conservation of landraces ex situ. The National Genebank housed at ICAR-NBPGR, New Delhi conserves around 550 accessions of landraces collected from the Central Western Ghats region surveyed in this report. Information collected from custodian farmers on specific uses will be helpful to enhance the utilization of these accessions.
The fibroid phenotype of biological naïve patients with rheumatoid arthritis are less likely to respond to anti-IL-6R treatment
Authors: Madsen Sofie Falkenløve , Sinkeviciute Dovile , Thudium Christian S. , Karsdal Morten A. , Bay-Jensen Anne-Christine
Published: May 2024

Type III collagen gene expression is upregulated in the synovium of patients with rheumatoid arthritis (RA) presenting the fibroid phenotype. The soluble type III collagen formation biomarker, PRO-C3, is known to measure fibrogenesis in fibrotic diseases. In this exploratory study, we aimed to investigate the association between fibrogenesis (PRO-C3) and the disease- and treatment response in patients with RA. We measured PRO-C3 in subsets of two clinical trials assessing the effect of the anti-interleukin-6 (IL-6) receptor treatment tocilizumab (TCZ) as monotherapy or polytherapy with methotrexate. PRO-C3 levels had weak or very weak correlations with the clinical parameters (Spearman’s). However, when the patients were divided into Disease Activity Score-28 groups characterized by the erythrocyte sedimentation rate (DAS28-ESR), there was a statistical difference between the PRO-C3 levels of the different groups (p < 0.05). To determine the response in relation to PRO-C3, a cut-off based on PRO-C3 levels and patients in remission (DAS28-ESR ≤ 2.6) was identified. This showed that a reduction in PRO-C3 after treatment initiation was associated with decreased DAS28-ESR and a higher response rate in patients with low PRO-C3 levels than in those with high PRO-C3 levels. This indicates that a fibrotic component affects the responsiveness of patients.
Multiphysics simulations of a cylindrical waveguide optical switch using phase change materials on silicon
Authors: Malek Mohammad Alireza , Nikoufard Mahmoud , Abdolghaderi Senour
Published: May 2024

This work presents the design and multiphysics simulation of a cylindrical waveguide-based optical switch using germanium-antimony-tellurium (GST) as an active phase change material. The innovative cylindrical architecture is theoretically analyzed and evaluated at 1550 nm wavelength for telecommunication applications. The dispersion relation is derived analytically for the first time to model the optical switch, while finite element method (FEM) and finite difference time domain (FDTD) techniques are utilized to simulate the optical modes, light propagation, and phase change dynamics. The fundamental TE01 and HE11 modes are studied in detail, enabling switching between low-loss amorphous and high-loss crystalline GST phases. Increasing the GST thickness is found to increase absorption loss in the crystalline state but also slows down phase transition kinetics, reducing switching speeds. A 10 nm GST layer results in competitive performance metrics of 0.79 dB insertion loss, 13.47 dB extinction ratio, 30 nJ average power consumption, and 3.5 Mb/s bit rate. The combined optical, thermal, and electrical simulation provides comprehensive insights towards developing integrated non-volatile photonic switches and modulators utilizing phase change materials.
Uncommon opsin’s retinal isomer is involved in mammalian sperm thermotaxis
Authors: Brandis Alexander , Roy Debarun , Das Ishita , Sheves Mordechai , Eisenbach Michael
Published: May 2024

In recent years it became apparent that, in mammals, rhodopsin and other opsins, known to act as photosensors in the visual system, are also present in spermatozoa, where they function as highly sensitive thermosensors for thermotaxis. The intriguing question how a well-conserved protein functions as a photosensor in one type of cells and as a thermosensor in another type of cells is unresolved. Since the moiety that confers photosensitivity on opsins is the chromophore retinal, we examined whether retinal is substituted in spermatozoa with a thermosensitive molecule. We found by both functional assays and mass spectrometry that retinal is present in spermatozoa and required for thermotaxis. Thus, starvation of mice for vitamin A (a precursor of retinal) resulted in loss of sperm thermotaxis, without affecting motility and the physiological state of the spermatozoa. Thermotaxis was restored after replenishment of vitamin A. Using reversed-phase ultra-performance liquid chromatography mass spectrometry, we detected the presence of retinal in extracts of mouse and human spermatozoa. By employing UltraPerformance convergence chromatography, we identified a unique retinal isomer in the sperm extracts—tri-cis retinal, different from the photosensitive 11-cis isomer in the visual system. The facts (a) that opsins are thermosensors for sperm thermotaxis, (b) that retinal is essential for thermotaxis, and (c) that tri-cis retinal isomer uniquely resides in spermatozoa and is relatively thermally unstable, suggest that tri-cis retinal is involved in the thermosensing activity of spermatozoa.
Magnetic nanoparticles in square-wave fields for breakthrough performance in hyperthermia and magnetic particle imaging
Authors: Barrera Gabriele , Allia Paolo , Tiberto Paola
Published: May 2024

Driving immobilized, single-domain magnetic nanoparticles at high frequency by square wave fields instead of sinusoidal waveforms leads to qualitative and quantitative improvements in their performance both as point-like heat sources for magnetic hyperthermia and as sensing elements in frequency-resolved techniques such as magnetic particle imaging and magnetic particle spectroscopy. The time evolution and the frequency spectrum of the cyclic magnetization of magnetite nanoparticles with random easy axes are obtained by means of a rate-equation method able to describe time-dependent effects for the particle sizes and frequencies of interest in most applications to biomedicine. In the presence of a high-frequency square-wave field, the rate equations are shown to admit an analytical solution and the periodic magnetization can be therefore described with accuracy, allowing one to single out effects which take place on different timescales. Magnetic hysteresis effects arising from the specific features of the square-wave driving field results in a breakthrough improvement of both the magnetic power released as heat to an environment in magnetic hyperthermia treatments and the magnitude of the third harmonic of the frequency spectrum of the magnetization, which plays a central role in magnetic particle imaging.
Generalized sleep decoding with basal ganglia signals in multiple movement disorders
Authors: Yin Zixiao , Yu Huiling , Yuan Tianshuo , Smyth Clay , Anjum Md Fahim , Zhu Guanyu , Ma Ruoyu , Xu Yichen , An Qi , Gan Yifei , Merk Timon , Qin Guofan , Xie Hutao , Zhang Ning , Wang Chunxue , Jiang Yin , Meng Fangang , Yang Anchao , Neumann Wolf-Julian , Starr Philip , Little Simon , Li Luming , Zhang Jianguo
Published: May 2024

Sleep disturbances profoundly affect the quality of life in individuals with neurological disorders. Closed-loop deep brain stimulation (DBS) holds promise for alleviating sleep symptoms, however, this technique necessitates automated sleep stage decoding from intracranial signals. We leveraged overnight data from 121 patients with movement disorders (Parkinson’s disease, Essential Tremor, Dystonia, Essential Tremor, Huntington’s disease, and Tourette’s syndrome) in whom synchronized polysomnograms and basal ganglia local field potentials were recorded, to develop a generalized, multi-class, sleep specific decoder – BGOOSE. This generalized model achieved 85% average accuracy across patients and across disease conditions, even in the presence of recordings from different basal ganglia targets. Furthermore, we also investigated the role of electrocorticography on decoding performances and proposed an optimal decoding map, which was shown to facilitate channel selection for optimal model performances. BGOOSE emerges as a powerful tool for generalized sleep decoding, offering exciting potentials for the precision stimulation delivery of DBS and better management of sleep disturbances in movement disorders.
Organic food has lower environmental impacts per area unit and similar climate impacts per mass unit compared to conventional
Authors: Hashemi Fatemeh , Mogensen Lisbeth , van der Werf Hayo M. G. , Cederberg Christel , Knudsen Marie Trydeman
Published: May 2024

In recent years, interest in studying the climate and environmental impact of organic food has grown. Here, we compared the environmental impacts of organic and conventional food using data from 100 life cycle assessment studies. Most studies focused on climate impacts, with fewer addressing biodiversity loss and ecotoxicity. Findings revealed no significant differences in global warming, eutrophication potential, and energy use per mass unit. However, organic food showed lower global warming, eutrophication potential, and energy use per area unit, with higher land use. Additionally, organic farming showed lower potential for biodiversity loss and ecotoxicity. Challenges in life cycle assessment include evaluating biodiversity, toxicity, soil quality, and carbon changes. The choice of functional units influences results, highlighting the importance of considering multiple units in assessing organic food’s environmental footprint. This study emphasizes the necessity for comprehensive assessments at both product and diet levels to support informed decisions.
A europium shuttle for launching perovskites to space: using Eu2+/Eu3+ redox chemistry to boost photostability and radiation hardness of complex lead halides
Authors: Ustinova Marina I. , Frolova Lyubov A. , Rasmetyeva Alexandra V. , Emelianov Nikita A. , Sarychev Maxim N. , Shilov Gennadii V. , Kushch Pavel P. , Dremova Nadezhda N. , Kichigina Galina A. , Kukharenko Andrey I. , Kiryukhin Dmitry P. , Kurmaev Ernst Z. , Zhidkov Ivan S. , Troshin Pavel A.
Published: May 2024

The incorporation of Eu2+ cations in lead-halide perovskites improves their photostability and radiation hardness with respect to γ-rays and high-energy electron fluences, which are the key prerequisites for aerospace applications of PSCs.
In situ synergistic reduced graphene oxide-boron carbon nitride nanosheet heterostructures for high-performance fabric-based supercapacitors
Authors: Zhang Yujiao , Huang Qitao , Zhou Liangliang , Liu Heng , Wang Cai-Feng , Zhu Liangliang , Chen Su
Published: May 2024

A high-performance fabric-based supercapacitor is developed by incorporating a 2D/2D heterostructure composite into PAN nanofibers.
In situ growth-etching synthesis of hierarchical SAPO-34 from recycled mother liquor for ethanol dehydration
Authors: Liu Shuhua , Zhang Hongxia , Zhang Jianxia , Bian Zhihao , Wang Fang , Han Dezhi , Wang Guangjian , Bing Liancheng
Published: May 2024

Hierarchical SAPO-34 zeolite catalysts were successfully synthesized via a one-step hydrothermal synthesis approach with the assistance of excess triethylamine (TEA).
Crystal-to-crystal polymerisation of monosubstituted [PW11O39Cu(H2O)]5− Keggin-type anions
Authors: Ruiz-Bilbao Estibaliz , Pache Aroa , Barrenechea Unai , Reinoso Santiago , San Felices Leire , Vivanco Maria dM. , Lezama Luis , Artetxe Beñat , Gutiérrez-Zorrilla Juan M.
Published: May 2024

Compound [C(NH2)3]10[{PW11O39Cu(H2O)}2{Cu(pic)2}]·10H2O (1, pic = picolinate) undergoes a thermally-triggered single-crystal-to-single-crystal transformation that involves an unprecedented solid-state polymerisation of monosubstituted Keggin anions.
Exploring the interaction between a fluorescent Ag(i)-biscarbene complex and non-canonical DNA structures: a multi-technique investigation
Authors: Binacchi Francesca , Giorgi Ester , Salvadori Giacomo , Cirri Damiano , Stifano Mariassunta , Donati Aurora , Garzella Linda , Busto Natalia , Garcia Begona , Pratesi Alessandro , Biver Tarita
Published: May 2024

The fluorescent [Ag(BIA)2]Cl complex is the first example of an Ag(i)-based complex that shows affinity for DNA G-quadruplexes and i-motifs.
A ratiometric substrate for rapid evaluation of transfer hydrogenation efficiency in solution
Authors: Young Yen-An , Nguyen Huong T. H. , Nguyen Hieu D. , Ganguly Tuhin , Nguyen Yennie H. , Do Loi H.
Published: May 2024

A method for the simultaneous monitoring of multiple transfer hydrogenation reactions using a microplate reader is reported.
Ruthenium confined within hollow spherical carbon nitride as an efficient catalyst for triggering peroxymonosulfate
Authors: Yin Yu , Tian Shuoyuan , Hu Bing , Asif Abdul Hannan , Cui Sheng , Wang Shaobin , Sun Hongqi
Published: May 2024

Ruthenium species were confined within hollow carbon nitride spheres to efficiently activate peroxymonosulfate to produce reactive radicals and singlet oxygen for decomposing a pharmaceutical contaminant in wastewater, i.e., acetaminophen.
Recent advances in asymmetric synthesis of chiral amides and peptides: racemization-free coupling reagents
Authors: Guo Yanyan , Wang Meiyu , Gao Yuan , Liu Guodu
Published: May 2024

Over past decades, chiral amides and peptides have emerged as powerful and versatile compounds due to their various biological activities and interesting molecular architectures.
Neuroprotective azaphilones from a deep-sea derived fungus Penicillium sp. SCSIO41030
Authors: Chen Weihao , Jiang Jiahui , Pang Xiaoyan , Song Yingying , Yang Zhiyou , Wang Junfeng , Liu Yonghong
Published: May 2024

Azaphilones 8 and 9 isolated from a deep-sea derived Penicillium sp. SCSl041030 dramatically promoted axonal regrowth against Aβ25–35 induced axonal atrophy, which is the first report of azaphilones with neuroprotective effects.
Doxorubicin-Polysorbate 80 conjugates: targeting effective and sustained delivery to the brain
Authors: Ram Prasad S. , Leena Sruthi Sudheendran , Deepthi Ani , Resmi A. N. , Jayasree Ramapurath S. , Sandhya K. S. , Jayakrishnan A.
Published: May 2024

Herein, doxorubicin (DOX) was conjugated to polysorbate 80 (PS 80). The DOX-PS 80 conjugate exhibited 3-fold higher blood brain barrier permeability than free DOX and released the DOX in a more sustained manner, highlighting the significance of polysorbate conjugates in addressing brain disorders.
Correction: DCID-mediated esterification of carboxylic acids with alcohols under mild conditions
Authors: Nasiri Farzaneh , Mokhtari Javad , Taheri Salman , Mirjafary Zohreh
Published: May 2024

Correction for ‘DCID-mediated esterification of carboxylic acids with alcohols under mild conditions’ by Farzaneh Nasiri et al., RSC Adv., 2023, 13, 27385–27390, https://doi.org/10.1039/d3ra04048h.
Anionic starch-based hybrid cryogel-embedded ZnO nanoparticles: tuning the elasticity and pH-functionality of biocomposites with dicarboxylic acid units
Authors: Ciftbudak Sena , Orakdogen Nermin
Published: May 2024

Weakly anionic semi-interpenetrating polymer network biocomposites based on starch-incorporated poly(acrylamide-co-itaconic acid)/ZnO were synthesized by a simple one-pot method via free radical polymerization.
Negative space charge modulated ion transport through PEDOT:PSS hydrogels integrating nanofluidic channels for highly efficient osmotic energy harvesting
Authors: Zhu Rui , Sun Peng , Cui Guofeng , Yu Yaoguang , Ke Shaojun , Zhao Jie
Published: May 2024

The exploitation of ion-selective membranes with high power density and low resistance is crucial for harvesting osmotic energy in natural environments.
Insights from experiment and machine learning for enhanced TiO2 coated glazing for photocatalytic NOx remediation
Authors: Lin Zhi-Peng , Li Yuankai , Haque Saif A. , Ganose Alex M. , Kafizas Andreas
Published: May 2024

TiO2-coated glass for photocatalytic NOx removal was optimised. Correlations between the synthesis parameters, coating properties, and photocatalytic activity was systematically studied through experimentation and machine learning tools for the first time.
Mapping current high-entropy materials for water electrolysis: from noble metal to transition metal
Authors: Ni Jing-Chang , Luan Yu-Xin , Wang Xiao-Feng , Tan Zhenquan , Song Xue-Zhi
Published: May 2024

This review gives a global map of HEMs on the basis of metal entities from noble metals to cheap transition metals and provide meaningful guidance to researchers for the exploration of advanced HEMs for water splitting.
Fundamental and technological aspects of thermochemical expansion of proton-conducting oxides: a case study of BaSn1−xScxO3−δ
Authors: Starostin G. N. , Tsvetkov D. S. , Starostina I. A. , Sereda V. V. , Akopian M. T. , Malyshkin D. A. , Ivanov I. L. , Murashkina A. A. , Zuev A. Yu , Medvedev D. A.
Published: May 2024

This work provides insight into the thermal and chemical expansion behaviors of proton-conducting oxides, using Sc-doped BaSnO3 materials as examples. Both fundamental and applied aspects related to thermo-chemical expansion are thoroughly discussed.
A controllable Y-shaped DNA structure assisted aptasensor for the simultaneous detection of AFB1 and OTA based on ARGET ATRP
Authors: Miao Mingsan , Guo Liang , Xue Jinyan , Jia Yuzhen , Cui Zhenzhen , Yang Huaixia
Published: May 2024

A fluorescent aptasensor was successfully constructed for sensitive AFB1 and OTA quantification based on a controllable Y-shaped DNA structure with ARGET ATRP.
Replacing Li+ in Li-TFSI with a benzene ring: constructing non-ionic p-dopants for stable and efficient perovskite solar cells
Authors: Wan Zhongquan , Jiang Shaoliang , Lu Hui , Zhu Jinqing , Wang Yuanxi , Zeng Huaibiao , Yin Haomiao , Wei Runmin , Luo Junsheng , Jia Chunyang
Published: May 2024

A novel non-ionic dopant Ph-TFSI for PSC was designed by replacing the Li+ in Li-TFSI with benzene ring, which exhibits many advantages, including non-ionic migration, non-hygroscopicity, good solubility, and the ability to directly dope HTMs.
In situ laser-assisted decoration of Au nanoparticles on 3D porous graphene for enhanced 2-CEES sensing
Authors: Zhang Ling , Yang Jie , Yang Junchao , Wei Jianan , Zhou Chuan , Zhao Jiang , Huang Qibin
Published: May 2024

In situ Au decorated laser-induced graphene (LIG/Au) behaves as an effective near-room-temperature 2-chloroethyl ethyl sulfide (2-CEES) sensor. It exhibits an enhanced response of 7.85‰ to 1.0 ppm 2-CEES, which is twice as that of pure LIG.
Enhanced electromagnetic wave absorption and mechanical performances of graphite nanosheet/PVDF foams via ice dissolution and normal pressure drying
Authors: Su Xiaogang , Zhang Yu , Wang Jun , Liu Yaqing
Published: May 2024

An ice dissolution-normal pressure drying strategy based on graphite nanosheet was proposed to prepare porous PVDF foams, which own exceptional microwave absorption (RLmax = −57.68 dB, EAB = 6.86 GHz) and compression strength (300.9 kPa).
Formation pathways of formic acid (HCOOH) in regions with methanol ices
Authors: Inostroza-Pino Natalia , Emmanuel Godwin Oko , Mardones Diego , Ge Jixing
Published: May 2024

We modeled the collisions between OH+ projectiles with kinetic energies ranging from 10 to 22 eV and an amorphous cold (CH3OH)10 substrate using Born-Oppenheimer molecular dynamics (BOMD) simulations. We conducted the simulations for a collision time of 400 femtoseconds (fs), during which we followed multiple bond-forming and breaking reactions. Here, we report four new pathways for the formation of formic acid HCOOH. We find new precursors such as CH3(OH)2+, HC(OH)2+, CH2OH+, and CH2(OH)2, which are essential in these pathways for the formation of formic acid. The methanodiol CH2(OH)2 and hydroxymethyl CH2OH+ cations have previously been identified as key precursors of formaldehyde. These pathways suggest new ways to form formic acid in methanol ice mantles on dust grains, offering alternative mechanisms leading to the formation of complex organic molecules (COMs) in space.
Metal-silicate mixing in planetesimal collisions
Authors: Shuai Kang , Schäfer Christoph M. , Burger Christoph , Hui Hejiu
Published: May 2024

Aims. Impacts between differentiated planetesimals are ubiquitous in protoplanetary discs and may mix materials from the core, mantle, and crust of planetesimals, thus forming stony-iron meteorites. The surface composition of the asteroid (16) Psyche represents a mixture of metal and non-metal components. However, the velocities, angles, and outcome regimes of impacts that mixed metal and silicate from different layers of planetesimals are debated. Our aim is to investigate the impacts between planetesimals that can mix large amounts of metal and silicate, and the mechanism of stony-iron meteorite formation.

Methods. We used smooth particle hydrodynamics to simulate the impacts between differentiated planetesimals with various initial conditions that span different outcome regimes. In our simulations, the material strength was included and the effects of the states of planetesimal cores were studied. Using a statistical approach, we quantitatively analysed the distributions of metal and silicate after impacts.

Results. Our simulations modelled the mass, depth, and sources of the metal–silicate mixture in different impact conditions. Our results suggest that the molten cores in planetesimals could facilitate mixing of metal and silicate. Large amounts of the metal–silicate mixture could be produced by low-energy accretional impacts and high-energy erosive impacts in the largest impact remnant, and by hit-and-run and erosive impacts in the second-largest impact remnant. After impact, most of the metal-silicate mixture was buried at depth, consistent with the low cooling rates of stony-iron meteorites. Our results indicate that mesosiderites potentially formed in an erosive impact, while pallasites potentially formed in an accretional or hit-and-run impact. The mixing of metal and non-metal components on Psyche may also be the result of impacts.
M3DIS – A grid of 3D radiation-hydrodynamics stellar atmosphere models for stellar surveys
Authors: Eitner Philipp , Bergemann Maria , Hoppe Richard , Nordlund Åke , Plez Bertrand , Klevas Jonas
Published: May 2024

Context. Large-scale stellar surveys, such as SDSS-V, 4MOST, WEAVE, and PLATO, require accurate atmospheric models and synthetic spectra of stars for accurate analyses of fundamental stellar parameters and chemical abundances.

Aims. The primary goal of our work is to develop a new approach to solve radiation-hydrodynamics (RHD) and generate model stellar spectra in a self-consistent and highly efficient framework.

Methods. We build upon the Copenhagen legacy RHD code, the MULTI3D non-local thermodynamic equilibrium (NLTE) code, and the DISPATCH high-performance framework. The new approach allows us to calculate 3D RHD models of stellar atmospheres on timescales of a few thousand CPU hours and to perform subsequent spectrum synthesis in local thermodynamic equilibrium (LTE) or NLTE for the desired physical conditions within the parameter space of FGK-type stars.

Results. We compare the 3D RHD solar model with other available models and validate its performance against solar observations, including the centre-to-limb variation of intensities and key solar diagnostic lines of H and Fe. We show that the performance of the new code allows to overcome the main bottleneck in 3D NLTE spectroscopy and enables calculations of multi-dimensional grids of synthetic stellar observables for comparison with modern astronomical observations.
Alternative statistical interpretation for the apparent plateaus in the duration distributions of gamma-ray bursts
Authors: Osborne Joshua Alexander , Bryant Christopher Michael , Bagheri Fatemeh , Shahmorad Amir
Published: May 2024

Context. The existence of a plateau in the short-duration tail of the observed distribution of cosmological long-soft gamma ray bursts (LGRBs) is posited to be the first direct evidence of collapsars. A similar plateau in the short-duration tail of the observed duration distribution of short-hard gamma ray bursts (SGRBs) has been suggested as evidence of compact binary mergers.

Aims. We present an equally plausible alternative interpretation for this evidence, based on a purely statistical approach.

Methods. Specifically, we show that the observed plateau in the short-duration tail of the duration distribution of LGRBs can naturally occur in the statistical distributions of strictly positive physical quantities, exacerbated by the effects of mixing with the duration distribution of SGRBs, observational selection effects, and data aggregation (e.g., binning) methodologies. The observed plateau in the short-duration tail of the observed distributions of SGRBs may likewise result from a combination of sample incompleteness and inhomogeneous binning of data. We further confirm the impact of these factors on the observation of a plateau in the duration distributions of GRBs through extensive numerical Monte Carlo simulations.

Results. This analysis corroborates and strengthens a purely statistical and sample-incompleteness interpretation of the observed plateau in the duration distribution of LGRBs and SGRBs, without invoking the physics of collapsars or jet-propagation through the stellar envelope.
Recent observations of the rotation of distant galaxies and the implication for dark matter
Authors: Nelson A. H. , Williams P. R.
Published: May 2024

Context. Recent measurements of gas velocity in the outer parts of high redshift galaxies suggest that steeply falling rotation curves may be common or even universal in these galaxies, in contrast to the near universal flat, non-declining rotation curves in nearby galaxies.

Aims. The aim was to investigate the implications of these postulated steeply falling rotation curves for the role of dark matter in galaxy formation.

Methods. Using an established computer code, the collapse of dark matter and baryonic matter together, starting with a variety of initial conditions, was simulated for comparison with the observed rotation curves. A simulation of collapsing baryonic matter on its own without dark matter was also carried out. The masses of the protogalaxies were chosen to produce a stellar disc in the same mass range as the observed galaxies at roughly the same redshift.

Results. As soon as a smooth stellar disc was formed in the baryonic matter, with properties similar to the observed high redshift galaxies, the computed rotation curves were without exception relatively flat to large radius in the gas disc. Only a simulation without a dark matter halo was able to reproduce the observed rotation curves.

Conclusions. This implies that if the high redshift steeply falling rotation curves turn out to be common, then the standard scenario of galaxy formation by baryonic matter falling into the potential well of a massive dark matter halo must be wrong, unless there is pressure support via velocity dispersion significantly higher than has so far been observed or resulted from our simulations. It would also imply that for these galaxies the flat rotation curves at low redshift must be due to dark matter which has subsequently fallen into the galactic potential well, or there must be some other explanation for their contemporary flat rotation curves other than dark matter.
Whistler-mode waves in the tail of Mercury’s magnetosphere: A numerical study
Authors: Ballerini Giulio , Lavorenti Federico , Califano Francesco , Henri Pierre
Published: May 2024

Context. Mercury presents a highly dynamic, small magnetosphere in which magnetic reconnection plays a fundamental role.

Aim. We aim to model the global characteristics of magnetic reconnection in the Hermean environment. In particular, we focus on waves observed during the third BepiColombo flyby.

Method. In this work, we used two fully kinetic three-dimensional (3D) simulations carried out with the iPIC3D code, which models the interaction of the solar wind with the Hermean magnetosphere. For the simulations, we used southward solar wind conditions that allow for a maximum magnetic coupling between the solar wind and the planet.

Results. Our simulations show that a significant wave activity, triggered by magnetic reconnection, develops near the diffusion region in the magnetotail and propagates at large scales in the night-side magnetosphere. We see an increase in electron temperature close to the diffusion region and we specifically observe narrowband whistler waves developing near the reconnection region. These waves propagate nearly parallel to the magnetic field at frequency f ∼ 0.5fce. In addition to the electromagnetic component, these waves also exhibit an electrostatic one. Furthermore, we observe a strong electron temperature anisotropy, suggesting it plays a role as the source of these waves.
Rapidly rotating Population III stellar models as a source of primary nitrogen
Authors: Tsiatsiou Sophie , Sibony Yves , Nandal Devesh , Sciarini Luca , Hirai Yutaka , Ekström Sylvia , Farrell Eoin , Murphy Laura , Choplin Arthur , Hirschi Raphael , Chiappini Cristina , Liu Boyuan , Bromm Volker , Groh Jose , Meynet Georges
Published: May 2024

Context. The first stars might have been fast rotators. This would have important consequences for their radiative, mechanical, and chemical feedback.

Aims. We discuss the impact of fast initial rotation on the evolution of massive Population III models and on their nitrogen and oxygen stellar yields.

Methods. We explore the evolution of Population III stars with initial masses in the range of 9 M⊙ ≤ Mini ≤ 120 M⊙, starting with an initial rotation on the zero-age main sequence equal to 70% of the critical one.

Results. We find that with the physics of rotation considered here, our rapidly rotating Population III stellar models do not follow a homogeneous evolution. They lose very little mass in the case in which mechanical winds are switched on when the surface rotation becomes equal to or larger than the critical velocity. The impact on the ionising flux appears to be modest when compared to moderately rotating models. Fast rotation favours, in models with initial masses above ∼20 M⊙, the appearance of a very extended intermediate convective zone around the H-burning shell during the core He-burning phase. This shell has important consequences for the sizes of the He- and CO-cores, and thus impacts the final fate of stars. Moreover, it has a strong impact on nucleosynthesis, boosting the production of primary 14N.

Conclusions. Fast initial rotation significantly impacts the chemical feedback of Population III stars. Observations of extremely metal-poor stars and/or starbursting regions are essential to provide constraints on the properties of the first stars.
Estimation of the lateral mis-registrations of the GRAVITY+adaptive optics system
Authors: Berdeu A. , Bonnet H. , Le Bouquin J.-B. , Édouard C. , Gomes T. , Shchekaturov P. , Dembet R. , Paumard T. , Oberti S. , Kolb J. , Millour F. , Berio P. , Lai O. , Eisenhauer F. , Garcia P. , Straubmeier C. , Kreidberg L. , Hönig S. F. , Defrère D.
Published: May 2024

Context.The GRAVITY+ upgrade implies a complete renewal of its adaptive optics (AO) systems. Its complex design, featuring moving components between the deformable mirrors and the wavefront sensors, requires the monitoring and auto-calibrating of the lateral mis-registrations of the system while in operation.

Aims.For preset and target acquisition, large lateral registration errors must be assessed in open loop to bring the system to a state where the AO loop closes. In closed loop, these errors must be monitored and corrected, without impacting the science.

Methods.With respect to the first requirement, our method is perturbative, with two-dimensional modes intentionally applied to the system and correlated to a reference interaction matrix. For the second requirement, we applied a non-perturbative approach that searches for specific patterns in temporal correlations in the closed loop telemetry. This signal is produced by the noise propagation through the AO loop.

Results.Our methods were validated through simulations and on the GRAVITY+ development bench. The first method robustly estimates the lateral mis-registrations, in a single fit and with a sub-subaperture resolution while in an open loop. The second method is not absolute, but it does successfully bring the system towards a negligible mis-registration error, with a limited turbulence bias. Both methods proved to robustly work on a system still under development and not fully characterised.

Conclusions.Tested with Shack-Hartmann wavefront sensors, the proposed methods are versatile and easily adaptable to other AO instruments, such as the pyramid, which stands as a baseline for all future AO systems. The non-perturbative method, not relying on an interaction matrix model and being sparse in the Fourier domain, is particularly suitable to the next generation of AO systems for extremely large telescopes that will present an unprecedented level of complexity and numbers of actuators.
Resolving high-z galaxy cluster properties through joint X-ray and millimeter analysis: Case study of SPT-CLJ0615-5746
Authors: Mastromarino C. , Oppizzi F. , De Luca F. , Bourdin H. , Mazzotta P.
Published: May 2024

We present a joint millimetric and X-ray analysis of hot gas properties in the distant galaxy cluster SPT-CLJ0615-5746 (z = 0.972). Combining Chandra observations with the South Pole Telescope (SPT) and Planck data, we performed radial measurements of thermodynamical quantities up to a characteristic radius of 1.2 R500. We exploited the high angular resolution of Chandra and SPT to map the innermost region of the cluster and the high sensitivity to the larger angular scales of Planck to constrain the outskirts and improve the estimation of the cosmic microwave background and the galactic thermal dust emissions. In addition to maximizing the accuracy of radial temperature measurements, our joint analysis allows us to test the consistency between X-ray and millimetric derivations of thermodynamic quantities via the introduction of a normalization parameter (ηT) between X-ray and millimetric temperature profiles. This approach reveals a substantial high value of the normalization parameter, ηT = 1.45−0.18+0.17, suggesting that the gas halo is aspherical. Assuming hot gas hydrostatic equilibrium within complementary angular sectors that intercept the major and minor elongation of the X-ray image, we infer a halo mass profile that results from an effective compensation of azimuthal variations of gas densities by variations in the ηT parameter. Consistent with earlier integrated X-ray and millimetric measurements, we infer a cluster mass of M500HE = 10.67−0.50+0.62 1014 M⊙.
The original composition of the gas forming first-generation stars in clusters: Insights from HST and JWST
Authors: Legnardi M. V. , Milone A. P. , Cordoni G. , Marino A. F. , Dondoglio E. , Jang S. , Lagioia E P. , Muratore F. , Ziliotto T. , Bortolan E. , Mohandasan A.
Published: May 2024

Globular cluster (GC) stars composed of pristine material, also known as first-generation (1G) stars, are not chemically homogeneous as they exhibit extended sequences in the chromosome map (ChM). Recent studies characterized 1G stars within the center of 55 Galactic GCs, revealing metallicity variations. Despite this progress, several unanswered questions persist, particularly concerning the link between the 1G metallicity spread and factors such as the radial distance from the cluster center or the host GC parameters. Additionally, it remains unclear whether the extended 1G sequence phenomenon is exclusive to old Galactic GCs with multiple populations. This work addresses these open issues, examining 1G stars in different environments. First, we combine Hubble Space Telescope (HST) and James Webb Space Telescope photometry of the GC 47 Tucanae to study 1G stars at increasing distances from the cluster center. We find that metal-rich 1G stars are more centrally concentrated than metal-poor ones, suggesting a metallicity radial gradient. Additionally, the two groups of 1G stars share similar kinematics. Since our analysis focuses on giant stars in the cluster center and M dwarfs in external fields, we discuss the possibility that the metallicity distribution depends on stellar mass. Subsequently, we analyze HST multi-band photometry of two simple-population clusters, NGC 6791 and NGC 1783, revealing elongated sequences in the ChM associated with metallicity variations. Finally, we investigate the 1G color distribution in 51 GCs, finding no connections with the host cluster parameters. These results shed light on the complex nature of 1G stars, providing insights into the GC formation environment.
Deep tomography for the three-dimensional atmospheric turbulence wavefront aberration
Authors: Zhang Lingxiao , Zhang Lanqiang , Zhong Libo , Rao Changhui
Published: May 2024

Context.Multiconjugate adaptive optics (MCAO) can overcome atmospheric anisoplanatism to achieve high-resolution imaging with a large field of view (FOV). Atmospheric tomography is the key technology for MCAO. The commonly used modal tomography approach reconstructs the three-dimensional atmospheric turbulence wavefront aberration based on the wavefront sensor (WFS) detection information from multiple guide star (GS) directions. However, the atmospheric tomography problem is severely ill-posed. The incomplete GS coverage in the FOV coupled with the WFS detection error significantly affects the reconstruction accuracy of the three-dimensional atmospheric turbulence wavefront aberration, leading to a nonuniform aberration detection precision over the whole FOV.

Aims.We propose an efficient approach for achieving accurate atmospheric tomography to overcome the limitations of the traditional modal tomography approach.

Methods.We employed a deep-learning-based approach to the tomographic reconstruction of the three-dimensional atmospheric turbulence wavefront aberration. We propose an atmospheric tomography residual network (AT-ResNet) that is specifically designed for this task, which can directly generate wavefronts of multiple turbulence layers based on the Shack-Hartmann (SH) WFS detection images from multiple GS directions. The AT-ResNet was trained under different turbulence intensity conditions to improve its generalization ability. We verified the performance of the proposed approach under different conditions and compared it with the traditional modal tomography approach.

Results.The well-trained AT-ResNet demonstrates a superior performance compared to the traditional modal tomography approach under different atmospheric turbulence intensities, various turbulence layer distributions, higher-order turbulence aberrations, detection noise, and reduced GSs conditions. The proposed approach effectively addresses the limitations of the modal tomography approach, leading to a notable improvement in the accuracy of atmospheric tomography. It achieves a highly uniform and high-precision wavefront reconstruction over the whole FOV. This study holds great significance for the development and application of the MCAO technology.
Long-term stellar activity of M dwarfs
Authors: Raetz St. , Stelzer B.
Published: May 2024

Studies of the rotation and activity of M type stars are essential in order to enhance our understanding of stellar dynamos and angular momentum evolution. Using the outstanding photometric capabilities of space telescopes, even those rotation signals with low amplitudes can now be investigated in previously unrivaled detail. By combining data of K2 and the TESS prime mission, the star spot activity of M dwarfs can be monitored over a timescale of half a decade. In the framework of our study on the rotation–activity relation for bright and nearby M dwarfs, we also aim to investigate their long-term activity. While K2 was observing fields distributed around the ecliptic plane, the TESS prime mission was oriented along a line of ecliptic longitude, with one camera centered on an ecliptic pole. Due to these different observing strategies, the overlap between K2 and the TESS prime mission is marginal. However, 45 stars from our sample were observed with both missions, and of these, two early M-type stars that fulfill our selection criteria, EPIC 202059229 and EPIC 245919787, were analyzed in more detail. We find that, for both stars, the rotation period did not change, while the rotational phase did change for EPIC 245919787 by ∼0.2. The amplitude of the spot-induced variability changed for both stars but more significantly for EPIC 245919787. By comparing the cumulative flare frequency distributions, we find that the flare activity for EPIC 202059229 is unchanged, while it slightly changes for EPIC 245919787 between the K2 and TESS epochs. Using a combination of light curves from K2 and TESS that span a baseline of up to 4.5 yr, we are able to measure significant differential rotation for EPIC 245919787. Furthermore, we show that combining missions like K2 and TESS is a promising method for detecting stellar activity cycles.
What drives the corpulence of galaxies?
Authors: de Almeida Abhner P. , Mamon Gary A. , Dekel Avishai , Lima Neto Gastão B.
Published: May 2024

Nearby dwarf galaxies display a variety of effective radii (sizes) at a given stellar mass, suggesting different evolution scenarios according to their final “stellar” size. The TNG hydrodynamical simulations present a bimodality in the z = 0 size–mass relation (SMRz0) of dwarf galaxies, at r1/2, ⋆ ∼ 450 pc. Using the TNG50 simulation, we explored the evolution of the most massive progenitors of dwarf galaxies (z = 0 log(M⋆/M⊙) between 8.4 and 9.2) that end up as central galaxies of their groups. We split these dwarfs into three classes of the SMRz0: “Normals” from the central spine of the main branch, and “Compacts” from the secondary branch as well as the lower envelope of the main branch. Both classes of Compacts see their stellar sizes decrease from z ∼ 1 onwards in contrast to Normals, while the sizes of the gas and dark matter (DM) components continue to increase (as for Normals). A detailed analysis reveals that Compacts live in poorer environments, and thus suffer fewer major mergers from z = 0.8 onwards, which otherwise would pump angular momentum into the gas, allowing strong gas inflows, producing inner star formation, and thus leading to the buildup of a stellar core. Compacts are predicted to be rounder and to have bluer cores. Compact dwarfs of similar sizes are observed in the GAMA survey, but the bimodality in size is less evident and the most compact dwarfs tend to be passive rather than star forming, as in TNG50. Our conclusions should therefore be confirmed with future cosmological hydrodynamical simulations.