bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interplay between particle trapping and heterogeneity in anomalous diffusion
Authors: Ribeiro Haroldo V. , Tateishi Angel A. , Lenzi Ervin K. , Magin Richard L. , Perc Matjaž 
Published: September 2023

AbstractHeterogeneous media diffusion is often described using position-dependent diffusion coefficients and estimated indirectly through mean squared displacement in experiments. This approach may overlook other mechanisms and their interaction with position-dependent diffusion, potentially leading to erroneous conclusions. Here, we introduce a hybrid diffusion model that merges a position-dependent diffusion coefficient with the trapping mechanism of the comb model. We derive exact solutions for position distributions and mean squared displacements, validated through simulations of Langevin equations. Our model shows that the trapping mechanism attenuates the impact of media heterogeneity. Superdiffusion occurs when the position-dependent coefficient increases superlinearly, while subdiffusion occurs for sublinear and inverse power-law relations. This nontrivial interplay between heterogeneity and state-independent mechanisms also leads to anomalous yet Brownian, and non-Brownian yet Gaussian regimes. These findings emphasize the need for cautious interpretations of experiments and highlight the limitations of relying solely on mean squared displacements or position distributions for diffusion characterization.
Trends in atmospheric methane concentrations since 1990 were driven and modified by anthropogenic emissions
Authors: Skeie Ragnhild Bieltvedt , Hodnebrog Øivind , Myhre Gunnar 
Published: September 2023

AbstractThe atmospheric methane trend is not fully understood. Here we investigate the role of the main sink, the main natural source, and anthropogenic emissions on the methane growth rate over the last three decades using numerical models and emission inventories. We find that the long-term trend is driven by increased anthropogenic methane emissions, while wetland emissions show large variability and can modify the trend. The anthropogenic influence on hydroxyl radical, through nitrogen oxides and carbon monoxide emissions, has modified the trend over the last decades and contributed to the atmospheric methane stabilization from 2000 to 2007. The hydroxyl radical increase prior to this stabilization period might have contributed to the decline in the isotopic ratio after 2007 due to the time dependent isotopic response of hydroxyl radical. Emission reductions due to COVID-19 restrictions via the influence on hydroxyl radical, possibly contributed to approximately two thirds of the increase in methane growth from 2019 to 2020.
ChainKeeper: A cross‐chain scheme for governing the chain by chain
Authors: Xu Yuwei , He Ran , Dai Shengjiang , Zhang Yujian 
Published: September 2023

AbstractWith the rapid application of consortium chains, supervising these systems has become a challenge for governments. The centralized model fails to deliver supervision services that are both open and transparent. Given the benefits of decentralization, non‐tampering, and traceability offered by blockchains, researchers propose the concept of ‘governing the chain by chain’, which involves supervising multiple consortium chains by constructing a blockchain. Under this idea, the cross‐chain scheme becomes the key to achieving excellent supervision. Existing studies have shortcomings and cannot meet the requirements of universality, security, and efficiency in cross‐chain supervision scenarios. Aiming at the challenges, we propose ChainKeeper, a cross‐chain scheme for governing the chain by chain. The innovation of our work lies in three points. First, a modular node proxy program is designed to adapt to various implementations of consortium chains. Second, a verifiable node random selection method is put forward to improve the throughput of cross‐chain data transmission. Finally, a verifiable identity threshold signature method is proposed to prevent the cheating behavior of malicious nodes. To verify the universality of ChainKeeper, we built a prototype system on three types of consortium chains. The experimental results show that ChainKeeper can achieve high throughput, outperforming two state‐of‐the‐art cross‐chain schemes.
Robust beamforming for dual‐function radar‐communication with imperfect channel state information
Authors: Zhu Jinkun , Song Yongping , Jin Tian , Liu Wei 
Published: September 2023

AbstractDual‐function radar and communication (DFRC) have recently received significant attention as an effective way to alleviate spectrum congestion and reduce system costs. Joint transmit beamforming plays a critical role in DFRC systems, as it can effectively reduce mutual interference and improve the performance of both the radar and communication systems. This paper investigates the problem of robust beamforming design with imperfect channel state information (CSI) to ensure communication performance while optimizing radar performance. Considering elliptically bounded CSI errors, the objective function is designed to minimize the radar loss function, which is related to the radar transmit beam pattern, subject to worst‐case signal‐to‐interference‐plus‐noise ratio constraints at each user, which ensure fairness between users. An efficient algorithm based on semidefinite relaxation and the S‐procedure is proposed to solve the non‐convex problem. Simulation results are presented to illustrate the effectiveness of the proposed robust beamforming scheme, which can reduce the impact of channel errors.
Bi‐level multi‐agent system (MAS) to protect DC microgrids (DCMGs) in free renewable sources and uncertainties penetration
Authors: Bamshad Ali , Ghaffarzadeh Navid 
Published: September 2023

AbstractDC microgrids (DCMGs) have significant advantages, but their protection can be a challenge for DCMGs expansion expressly in distributed generation sources’ (DGS) tendance. This paper proposes a quick, and precise strategy to perceive and trip any fault in DCMGs in the free tendance of DGS. A bi‐level multi‐agent system (MAS) is proposed to protect the DCMG and DGs. The MAS first level perceives the fault in DCMG via a discrete wavelet transform (DWT). The multiply of two harvest levels’ summation of DWT is exerted to detect and distinguish DC lines faults. The MAS second level detects the fault in DGS and their switchers to the point of common connection (PCC) via a differential pole (DP) controller. A four bus DCMG containing solar PV and wind sources is implemented, and the results demonstrate that the proposed plan can recognize and trip the fault by 100% of reliability.
Microwave diagnostics of pulsed atmospheric discharge with electrolytic electrode and long‐lived luminous formation in its afterglow
Authors: Zhao Shixin , Lyu Xingbao , Astafiev Aleksandr , Yuan Chengxun , Miao Lin , Yao Jingfeng , Wang Ying , Kudryavtsev Anatoly , Chirtsov Aleksandr , Shabanov Gennadii , Zhou Zhongxiang 
Published: September 2023

AbstractThe Gatchina discharge phenomenon holds significant promise as a laboratory model for simulating ball lightning. However, crucial aspects concerning the plasma components of the resulting afterglow remain unresolved. Notably, the measurement of the electron density, a critical parameter, has not been fully achieved thus far. In this study, microwave diagnostics and video recording were employed during a pulsed Gatchina discharge, along with synchronous measurement of discharge current and voltage. Distinct antennas were positioned at different heights to enable separate diagnosis of the discharge and the ensuing long‐lived afterglow. The findings revealed that during the active phase of the Gatchina discharge, the plasma density was substantial enough to cause reflection of an electromagnetic wave with a frequency of 20 GHz from this highly conductive object. In the afterglow, the signal experienced only a moderate weakening of 10–20 percent, facilitating the determination of the time dependence of average electron density during the afterglow's passage between the two antennas. These measurements verified the unusually slow plasma decay in the afterglow of the Gatchina discharge, suggesting the potential significance of chemi‐ionisation processes involving long‐lived (metastable) particles.
Observation and verification of surface electrical explosion driven by radial‐distributed pulsed current in laboratory lightning strike test
Authors: Han Ruoyu , Cao Yuchen , Liu Yakun , Chen Xi , Li Ting , Li Chen , Li Pengfei 
Published: September 2023

AbstractThe laboratory lightning test is essential for assessing the effectiveness of lightning strike protection (LSP). Particularly, direct lightning strike damage can be performed with pulsed current injection into the specimen. This paper focuses on the dynamic process of arc plasma and shock wave behaviour in the vicinity of the ‘strike’ point. A rod‐plate discharge load is built for testing aluminium and coated plate under 40‐kA‐level pulsed current. The visualisation of the luminous discharge plasma and its flow field via high‐speed photography (from different angles) is meticulously designed and implemented, synchronised with electro‐physical diagnostics. The results indicate some new mechanisms for lightning strike damage, apart from the impulse heat loading from the thermal arc. The transient current injection through the arc root concentrates on a thin skin layer (skin‐depth effect), with the radial‐attenuated current density, driving asynchronously electrical explosions on the plate surface. The inhomogeneous Joule heating of the plate leads to outwardly propagating phase transition and shock wave along the conductive surface. In addition, the electro‐thermal instability is observed and regarded as the seed of irregular erosion region. Spectroscopic information reveals two different plasma states of main discharge arc channel and adjacent surface electrical explosion. The correspondence of the physical mechanism of electrical explosion and optical radiation is established. Microscopic images for different regions depict erosion characteristics and summarise influencing factors, further confirming the mechanism above. The research clarifies the role of skin‐depth effect in transaction arc erosion for electrode, complements the electrical explosion theory with unevenly distributed current and helps optimise strategies of LSP.
Fuzzy model predictive control for frequency regulation of temporary microgrids during load restoration
Authors: Wang Zhixian , Wang Ying , Wu Jiping , Zhang Kaifeng 
Published: September 2023

AbstractTemporary microgrids containing a high proportion of distributed renewable generations can offer great benefits during the recovery stage after large‐scale power system blackout, by picking up critical load and speeding up the entire grid recovery process. To solve the frequency security problem of temporary microgrids faced in the load restoration process, this paper proposes an adaptive fuzzy model predictive control (adaptive fuzzy‐MPC) strategy to obtain effective frequency regulation to suit the special characteristics of this process. First, the load restoration plan within a short time frame is regarded as the feedforward information and assists in the establishment of the MPC model. Then, considering the uncertainty of renewable distributed generations, the regulation resources are cooperated by an adaptive fuzzy controller which provides the weights of different regulation resources adopted in MPC. Specifically, the base weights of the energy storage system and renewable distributed generations are obtained from fuzzy rules, and then the weight for each regulation resource is modified by the designed adjustment rules. Simulation results illustrate that the proposed strategy can efficiently improve frequency performance while making various frequency regulation resources with different regulation capacities cooperate properly, which can further accelerate the load restoration progress and enhance system resilience.
Research on single target cognitive electronic reconnaissance strategy for unmanned aerial vehicle
Authors: Zhang Yun , Chen Zili , Yan Yunbin , Jiang Fangqing , Gao Xijun 
Published: September 2023

AbstractThe integration of electronic reconnaissance platforms and payloads in the electromagnetic and spatial domains of cognition is necessary for the successful execution of cognitive electronic reconnaissance missions. However, in partially observable environments, platforms and payloads interact in separate operational domains, making it a challenge for the model. The authors create a theoretical model of cognitive electronic reconnaissance, present an analysis method of model elements and derives adequate requirements for optimal radiation source sorting or recognition. Then, a 3D cognitive reconnaissance simulator ‘Scouter’ to simulate the dynamic interaction process of space electronic reconnaissance missions is developed and a deep reinforcement learning framework to optimise the electronic reconnaissance strategies of Unmanned Aerial Vehicle (UAV) is designed. For the first time, a method for judging reconnaissance area coverage using a behavioural angle is proposed. This method enables a deep reinforcement learning‐based UAV with better reconnaissance behaviours and to realise the stable targeting of the target by the receiving antenna beam during reconnaissance. Moreover, the fast convergence of UAV agent training is ensured through the normalisation of partially observable status and reward shaping. Verified by adequate numerical simulations, a trained UAV can complete a 100 reconnaissance cycles mission with a completion rate of 91.9%. Even after the reconnaissance cycles are prolonged to 600, the mission completion rate can still be maintained at 78.5%. The most satisfying aspect is that the UAV comprehends the idea of reconnaissance and behaves in a way that is typical of it, such as by reciprocating or circling the edge of the radar's detecting power.
X-ray luminosity-star formation rate scaling relation: Constraints from the eROSITA Final Equatorial Depth Survey (eFEDS)
Authors: Riccio G. , Yang G. , Małek K. , Boquien M. , Junais  , Pistis F. , Hamed M. , Grespan M. , Paolillo M. , Torbaniuk O. 
Published: September 2023

Aims.We present measurements of the relation between X-ray luminosity and star formation activity for a sample of normal galaxies spanning the redshift range between 0 and 0.25. We use data acquired by SRG/eROSITA for the performance and verification phase program called eROSITA Final Equatorial Depth Survey (eFEDS). The eFEDS galaxies are observed in the 0.2−2.3 keV band.Methods.Making use of a wide range of ancillary data, spanning from the ultraviolet (UV) to mid-infrared wavelengths (MIR), we estimated the star formation rate (SFR) and stellar mass (Mstar) of 888 galaxies, using Code Investigating GALaxy Emission (CIGALE). In order to study sources whose X-ray emission is dominated by X-ray binaries (XRBs), we classified these galaxies into normal galaxies and active galactic nuclei by making use of the observed fluxes in the X-ray, optical, and MIR ranges, as well as the results from the SED fitting. To isolate the contribution of XRBs, which scale with the SFR andMstar, we subtracted the contribution of hot gas, coronally active binaries, and cataclysmic variables to the total X-ray emission. We divided our sample of normal galaxies in star-forming (SFGs) and quiescent galaxies according to their position on the main sequence.Results.We confirm a linear correlation between the X-ray luminosity and the SFR for our sample of SFGs, shown previously in the literature. However, we find this relation to be strongly biased by the completeness limit of the eFEDS survey. Correcting for completeness, we find the fitted relation to be consistent with the literature. We also investigated the relation between X-ray emission from both LMXBs and HMXBs populations withMstarand SFR, respectively. Correcting for completeness, we find our fitted relation to considerably scatter from the literature relation at high specific SFR (SFR/Mstar). We conclude that without accounting for X-ray non-detections, it is not possible to employ eFEDS data to study the redshift evolution of the LMXBs and HMXBs contributions due to completeness issues. Furthermore, we find our sources to largely scatter from the expected Lx/SFR vs. specific SFR relation at high redshift. We discuss the dependence of the scatter on the stellar mass, metallicity, or the globular cluster content of the galaxy.
Interaction of H2S with H atoms on grain surfaces under molecular cloud conditions
Authors: Santos J. C. , Linnartz H. , Chuang K.-J. 
Published: September 2023

Context. Hydrogen sulfide (H2S) is thought to be efficiently formed on grain surfaces through the successive hydrogenation of sulfur atoms. Its non-detection so far in astronomical observations of icy dust mantles thus indicates that effective destruction pathways must play a significant role in its interstellar abundance. While chemical desorption has been shown to remove H2S very efficiently from the solid phase, in line with H2S gas-phase detections, possible ice chemistry triggered by the related HS radical have been largely disregarded so far, despite it being an essential intermediate in the H2S + H reaction scheme.
Aims. We aim to thoroughly investigate the fate of H2S upon H-atom impact under molecular cloud conditions, providing a comprehensive analysis combined with detailed quantification of both the chemical desorption and ice chemistry that ensues.
Methods. We performed experiments in an ultrahigh vacuum chamber at temperatures between 10 and 16 K in order to investigate the reactions between H2S molecules and H atoms on interstellar ice analogs. The changes in the solid phase during H-atom bombardment were monitored in situ by means of reflection absorption infrared spectroscopy (RAIRS), and desorbed species were complementarily measured with a quadrupole mass spectrometer (QMS).
Results. We confirmed the formation of H2S2 via reactions involving H2S + H and quantified its formation cross section under the employed experimental conditions. Additionally, we directly assessed the chemical desorption of H2S by measuring the gas-phase desorption signals with the QMS, providing unambiguous desorption cross sections. Chemical desorption of H2S2 was not observed. The relative decrease of H2S ices by chemical desorption changed from ~85% to ~74% between temperatures of 10 and 16 K, while the decrease as the result of H2S2 formation was enhanced from ~15% to ~26%, suggesting an increasingly relevant sulfur chemistry induced by HS radicals at warmer environments. The astronomical implications are further discussed.
Prediction of even and odd sunspot cycles
Authors: Asikainen Timo , Mantere Jani 
Published: September 2023

Here we study the prediction of even and odd numbered sunspot cycles separately, thereby taking into account the Hale cyclicity of solar magnetism. We first show that the temporal evolution and shape of all sunspot cycles are extremely well-described by a simple parameterized mathematical expression. We find that the parameters describing even sunspot cycles can be predicted quite accurately using the sunspot number 41 months prior to sunspot minimum as a precursor. We find that the parameters of the odd cycles can be best predicted with maximum geomagnetic aa index close to the fall equinox within a 3-year window preceding the sunspot minimum. We use the found precursors to predict all previous sunspot cycles and evaluate the performance with a cross-validation methodology, which indicates that each past cycle is very accurately predicted. For the coming sunspot cycle 25 we predict an amplitude of 171 ± 23 and the end of the cycle in September 2029 ± 1.9 years. We are also able to make a rough prediction for cycle 26 based on the predicted cycle 25. While the uncertainty for the cycle amplitude is large we estimate that the cycle 26 will most likely be stronger than cycle 25. These results suggest an increasing trend in solar activity for the next decades.
Systematic Review of WHO Grade 4 Astrocytoma in the Cerebellopontine Angle: The Impact of Anatomic Corridor on Treatment Options and Outcomes
Authors: Dang Danielle D. , Gong Andrew D. , Dang John V. , Mugge Luke A. , Mansinghani Seth , Ziu Mateo , Cohen Adam L. , Vyas Nilesh 
Published: September 2023

AbstractBackground Despite advances in multimodal oncologic therapies and molecular genetics, overall survival (OS) in patients with high-grade astrocytomas remains poor. We present an illustrative case and systematic review of rare, predominantly extra-axial World Health Organization (WHO) grade 4 astrocytomas located within the cerebellopontine angle (CPA) and explore the impact of anatomic location on diagnosis, management, and outcomes.Methods A systematic review of adult patients with predominantly extra-axial WHO grade 4 CPA astrocytomas was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines through December 2022.Results Eighteen articles were included comprising 21 astrocytomas: 13 exophytic tumors arising from the cerebellopontine parenchyma and 8 tumors originating from a cranial nerve root entry zone. The median OS was 15 months with one-third of cases demonstrating delayed diagnosis. Gross total resection, molecular genetic profiling, and use of ancillary treatment were low. We report the only patient with an integrated isocitrate dehydrogenase 1 (IDH-1) mutant diagnosis, who, after subtotal resection and chemoradiation, remains alive at 40 months without progression.Conclusion The deep conical-shaped corridor and abundance of eloquent tissue of the CPA significantly limits both surgical resection and utility of device-based therapies in this region. Prompt diagnosis, molecular characterization, and systemic therapeutic advances serve as the predominant means to optimize survival for patients with rare skull base astrocytomas.
The Effect of SARS-CoV-2 İnfection on Perinatal Outcomes in Hypertensive Disorders of Pregnancy
Authors: Farisoğulları Nihat , Denizli Ramazan , Sakcak Bedri , Tanaçan Atakan , Kara Özgür , Şahin Dilek 
Published: September 2023

Abstract
Objective To evaluate the fetal and maternal effects of the severe acute respiratory syndrome virus 2 (SARS-CoV-2) infection in women with hypertensive disorders of pregnancy.
Methods Patients with hypertensive disorders of pregnancy and SARS-CoV-2 polymerase chain reaction (PCR) positivity (n = 55) were compared with cases with similar characteristics and PCR negativity (n = 53). The study group was further divided into two groups as severe (n = 11) and nonsevere (n = 44) coronavirus disease 2019 (COVID-19). The groups were compared in terms of clinical characteristics and perinatal outcomes.
Results The study and control groups were similar in terms of maternal age, parity, gestational age at diagnosis, type of hypertensive disorders, magnesium sulfate administration rate, gestational age at birth, birth weight, Apgar scores, and maternal complications. However, all cases of fetal loss (n = 6) were observed in the SARS-CoV-2 positive group (p = 0.027). From the 6 cases, there were 5 in the nonsevere group and 1 patient in the severe SARS-CoV-2 positive group. Moreover, higher rates of maternal complications, lower oxygen saturation values, and intensive care unit admissions were observed in the severe COVID-19 group.
Conclusion Physicians should be cautious about the management of hypertensive disorders of pregnancy cases with SARS-CoV-2 positivity. Fetal loss seems to be more common in cases with SARS-CoV-2 positivity and severe COVID-19 seems to be associated with higher rates of maternal complications. Close follow-up for fetal wellbeing and active management of severe cases in terms of maternal complications seem to be favorable.