bluuebunny/crossref_metadata_2025 huggingface dataset:
On the theory of superconducting superstructures
Authors: Gogadze G. A.
Published: January 2025

A model structure of the Josephson type formed by periodically alternating layers of superconducting and normal metals (superconducting superlattice) is considered. The influence of phase fluctuations of the order parameter of the superconducting layers on the spectral structure of quasiparticle excitations is investigated. The conditions of applicability of the model under investigation are formulated.
Solitons in low-dimensional antiferromagnets
Authors: Ivanov B. A. , Kolezhuk A. K.
Published: January 2025

The structure, dynamics, and thermodynamics of magnetic solitons in low-dimensional antiferromagnets (AFMs) are reviewed from a unified point of view. Primary attention is given to problems for which experimental data are available. The analysis is based on simple phenomenological equations describing the dynamics of AFMs in terms of a single antiferromagnetism vector, which have the form of a Lorentz-invariant σ model (with the magnon phase velocity selected as the working velocity) in the simplest model of an AFM. The reduction in symmetry of an AFM in the presence of an external magnetic field or with allowance for Dzyaloshinskiĭ interaction violates Lorentz invariance. The restructuring of one-dimensional solitons of the kink type at a finite velocity is discussed, along with its influence on the soliton thermodynamics of quasi-one-dimensional magnetic media. The soliton solutions are subjected to quasiclassical quantization. It is shown that the dynamics of the internal degrees of freedom of a kink in a homogeneous AFM has a quantum nature, which becomes conspicuous in the investigation of two-parameter solitons of the bion type in almost-easy-axis AFMs. Two-dimensional topological solitons such as localized and nonlocalized magnetic vortices are discussed together with their contribution to the thermodynamics of two-dimensional AFMs. The current status of the problem of observing magnetic solitons experimentally in quasi-two-dimensional AFMs is reviewed, and various possible directions of future research are considered.
Magnetoplasmons in a system of surface electrons in helium at a boundary between regions with different charge densities
Authors: Kirichek O. I. , Berkutov I. B.
Published: January 2025

Plasma waves in the form of edge magnetoplasmons at a boundary between two regions with different densities of surface electrons localized above superfluid helium are investigated experimentally. Measurements are performed at a temperature of 1.1 K in magnetic fields up to 0.2 T. The experimental results are in good agreement with the theoretical prediction that the velocity of edge magnetoplasmons depends linearly on the difference between the electron densities, whereas the Q of magnetoplasmon resonance depends nonlinearly on this difference.
Quantum topological effects in a metallic ring with an Anderson impurity
Authors: Zvyagin A. A.
Published: January 2025

Spin and charge persistent currents in a metallic ring with an Anderson impurity are studied. It is shown that the impurity changes are caused by the external magnetic and electric fluxes — the Aharonov–Bohm and Aharonov–Casher type oscillations (the magnitudes and the periods) — in contrast with the normal metallic case. For instance, the Aharonov–Bohm oscillations look like the type II superconductor situation. These effects are a manifestation of the Luttinger liquid nature of the considered system.
On the possible role of nonlinear magnetic excitations in high-temperature superconductors
Authors: Loktev V. M. , Stefanovich V. A.
Published: January 2025

The formation of vortexons (bound states of holes and vortices), whose pairing is ensured by the attraction between vortices with opposite topological charges, is predicted.
On the possibility of superfluidity in a system of surface electrons paired with substrate holes
Authors: Shevchenko S. I. , Terent’ev S. V. , Kovdrya Yu. Z.
Published: January 2025

A new two-dimensional Bose system consisting of surface electrons over a film of superfluid helium (or solidified hydrogen or neon), which are paired with holes from the substrate, is proposed. In the case under consideration, the concentration is low and the size of electron–hole pairs is much smaller than their average separation. The coupling energy of an electron–hole pair and its size are determined. The temperature Tc of transition to the superfluid state is estimated. The conditions under which the crystallization temperature Tm is lower than Tc and crystallization is absent down to zero temperature are determined. The localization of pairs by impurities and irregularities of the substrate is considered. The density of impurities below which the localization of pairs does not affect significantly the phase state of the system is calculated. Experiments for detecting these effects are proposed.
Influence of magnetic field on ferroelastic and ferroelectric properties of rare-earth molybdates
Authors: Chupis I. E.
Published: January 2025

A thermodynamic description is proposed for the influence of a magnetic field on ferroelectric and ferroelastic properties of rare-earth molybdates for the field orientation along and at right angles to the spontaneous polarization. In the case of transverse orientation, the description is in accord with experimentally observed variations of electric polarization and deformation in terbium molybdate. Various types of dependence of strain, electric polarization, and magnetic moment on the magnetic field parallel to spontaneous polarization are obtained, and a first-order phase transition in magnetic field, which is induced by magnetoelectric interaction in the ferroelastic, ferroelectric, and magnetic subsystems, is predicted. An expression is obtained for the shift of transition temperature in a magnetic field.
Low-frequency charge density excitations and high T
c superconductivity in cuprate metal-oxide compounds. II. The HTS problem after discovery of high-temperature superconductors: achievements and outlooks (A review)
Authors: Pashitskiĭ È. A.
Published: January 2025

In the second part of the review, the theoretical concept concerning the leading role of low-frequency collective charge density excitations in the HTS mechanism and in manifestations of various anomalies in physical properties of metal-oxide compounds (MOC) both in the superconducting and in the normal (metallic) state is developed, proceeding from an analysis of a large body of experimental data.
Significant improvement of energy storage density and efficiency of 0.72Bi0.5Na0.5TiO3-0.28SrTiO3 ceramics and study of the mechanism of high temperature energy storage performance
Authors: Shi Peng , Liu Jin , Song Yuechan , Liu Lina , Wu Wenwen , Zhou Xiaobin , Chen Xiaoming , Jia Yanmin , Lou Xiaojie , Liu Peng
Published: January 2025

The energy storage properties of the 0.72Bi0.5Na0.5TiO3-0.28SrTiO3 system have been heavily investigated; however, achieving both high recoverable energy storage density (Wr) and large energy efficiency (η) remains a challenge. In this study, relaxor ferroelectric ceramics exhibiting high Wr and η were prepared by introducing BaSnO3 into 0.9(Bi0.5Na0.5)0.72Sr0.28TiO3-0.1Bi(Mg0.5Ti0.5)O3 relaxor ceramics. A remarkable Wr of 7.5 J/cm3 and η of 91.2% were achieved in the 0.94[0.9(Bi0.5Na0.5)0.72Sr0.28TiO3-0.1Bi(Mg0.5Ti0.5)O3]-0.06BaSnO3 ceramic at an electric field of 460 kV/cm. The η and the energy storage potential (Wr/Eb), respectively, surpass those reported for most ceramics in recent years. The introduction of high-temperature-stable BaSnO3 imparted excellent temperature and frequency stability to the ceramic. The ceramic exhibited a Wr of 3.6 J/cm3 and an η of 79.6% at 160 °C and 265 kV/cm. The sample has a power density of 202.8 MW/cm3, an energy density of 2.2 J/cm3 at an electric field of 260 kV/cm, and a fast charge–discharge capability.
Analytical study of steady state axisymmetric stagnation-point gold–blood Casson nanofluid through a rotating stretchable disk
Authors: Ali Usman , Khan Hamid , Khan Waris , Mahmoud Emad E. , Kouki Marouan , Aljedani Jabr , Garalleh Hakim AL
Published: January 2025

Nanofluids find extensive applications in enhancing the thermodynamic efficiency of thermal systems across various domains of engineering and scientific disciplines. This study aims to explore the complex relationship between the varying thermal conductivity and viscosity impact in nanofluid dynamics. The main objective of this study is to examine the three-dimensional stagnation flow of Casson nanofluid across a stretching and spinning disk, influenced by a magnetic source. The Navier–Stokes model for flow systems includes Brownian diffusion and thermophoresis. By using scaling variables, the complex system of partial differential equations is simplified into a set of coupled high degree nonlinear ordinary differential equations with convective boundary conditions. The homotopy technique is applied for analytic solutions. The optimization analysis is conducted on heat transfer rate and surface drag force coefficient using response parameters. The influence of the different parameters for the flow problem has been discussed and is shown through graphs. The finding of our study is that the velocity profiles increase in both radial directions as well as in the azimuthal direction by varying the rotation parameter strength, while the temperature gradient profile dwindles. Finally, the precision of the presented model is reaffirmed by means of a graphical juxtaposition with published data under a specific limiting scenario.
Cavity-enhanced high-order harmonic generation for high-performance time-resolved photoemission experiments
Authors: Allison Thomas K. , Kunin Alice , Schönhense Gerd
Published: January 2025

Recent breakthroughs in high repetition-rate extreme ultraviolet (XUV) light sources and photoelectron analyzers have led to dramatic advances in the performance of time-resolved photoemission experiments. In this perspective article, we discuss the application of cavity-enhanced high-order harmonic generation, with repetition rates exceeding 10 MHz, to photoemission experiments using advanced endstations incorporating time-of-flight photoelectron analyzers. We discuss recent results, perspective on future areas for further technological improvement, and the wide array of science enabled by ultrafast XUV photoemission experiments, now in a qualitatively new regime.
Tunable qubit quantum battery with delta-pulse driving
Authors: Ukhtary M. Shoufie , Rangkuti Choirun Nisaa
Published: January 2025

A quantum battery consisting of two coupled qubits driven by a delta-pulse is investigated. By using the framework of open quantum system, we obtain analytically several quantities describing the performance of the quantum battery. In particular, we are interested in the stored energy and the extractable energy known as ergotropy. We discover that by tuning the driving strength and the coupling strength, we can isolate the origin of the ergotropy: quantum coherences, population inversion, or combination of them. Furthermore, increasing the coupling strength not only enhances the stored energy, the ergotropy and charging power, but also reducing the charging time, which boosts the performance of the quantum battery.
Robust hybrid perovskite self-rectifying memristor for brain-inspired computing and data storage
Authors: Khemnani Manish , Jain Muskan , Hirpara Denish , Kumar Manoj , Tripathi Brijesh , Solanki Ankur
Published: January 2025

Conventional computing architectures are not suited to meet the unique workload requirements of artificial intelligence and deep learning, which has sparked a growing interest in memory-centric computing. One primary challenge in this field is sneak path current in memory devices, which degrades data storage and reliability. Another critical issue is ensuring device performance stability over time and under varying environmental conditions. To overcome these challenges, in this work, we introduce a Dion–Jacobson perovskite-based self-rectifying memory cell that not only reduces the sneak path current but also demonstrates remarkable stability in electrical parameters. The fabricated device maintains consistent performance, including rectification ratio (∼103), on/off ratio (∼103), and set voltage (∼0.52 V), for over 200+ days within a temperature range of 25–70 °C and relative humidity conditions up to 70%RH. Importantly, our work represents an innovative step forward in the observation of self-rectification and stable performance in perovskite-based devices, showing the way for their widespread application in memory-centric computing architectures. Furthermore, to understand the electrical behavior across its different states, i.e., high resistance state and low resistance state, electrochemical impedance spectroscopy is performed, which gives insight into the individual contribution of resistance, capacitance, and inductance.
Does the fluid-static equilibrium of a self-gravitating isothermal sphere of van der Waals' gas present multiple solutions?
Authors: Giordano Domenico , Amodio Pierluigi , Iavernaro Felice , Mazzia Francesca
Published: January 2025

We take up the investigation we left in the future-work stack in Giordano et al. [“Fluid statics of a self-gravitating isothermal sphere of van der Waals' gas,” Phys. Fluids 36, 056127 (2024)], in which we pointed out the obvious necessity to inquire about the existence or absence of values of the characteristic numbers α and β in correspondence to which the perfect-gas model's self-gravitational effects, namely, upper boundedness of the gravitational number, spiraling behavior of peripheral density, oscillating behavior of central density, and the existence of multiple solutions corresponding to the same value of the gravitational number, appear also for the van der Waals' model. The development of our investigation brings to the conversion of our M2 scheme based on a second-order differential equation into an equivalent system of two first-order differential equations that incorporates Milne's homology invariant variables. The converted scheme 1oM2 turns out to be much more efficacious than the M2 scheme in terms of numerical calculations' easiness and richness of results. We use the perfect-gas model as benchmark to test the 1oM2 scheme; we re-derive familiar results and put them in a more general and rational perspective that paves the way to deal with the van der Waals' gas model. We introduce variable transformations that turn out to be the key to study (almost) analytically the monotonicity of the peripheral density with respect to variations of the gravitational number. The study brings to the proof that the gravitational number is not constrained by upper boundedness, the peripheral density does not spiral, and the central density does not oscillate for any couple of values assumed by the characteristic numbers α and β; however, multiple solutions corresponding to the same value of the gravitational number can exist but their genesis is completely different from that of the perfect-gas model's multiple solutions. We provide the boundary in the α, β plane between the two regions of solution's uniqueness and multiplicity. Finally, by the application of the 1oM2 scheme, we resolve the mystery of the steep curve corresponding to the “60 km” case considered by Aronson and Hansen [“Thermal equilibrium states of a classical system with gravitation,” Astrophys. J. 177, 145 (1972)] and we even detect another solution that had somehow escaped the attention of those authors.
Experimental and numerical analysis of hydraulic performance in an axial-flow pump under diverse inflow conditions
Authors: Wang Dongsheng , Mu Tong , Feng Jiangang , Zhang Rui , Fei Zhaodan , Xu Hui , Zhang Peipei
Published: January 2025

Axial-flow pumps have complex hydraulic performance under diverse conditions, especially under low-flow conditions, which may occur rotational stall and brings serious system vibration. By combining experiments and numerical simulation analysis, the fine features of the local internal flow field in multi-flow rate conditions are accurately reflected, revealing the mechanism of changes in the internal flow field and hydraulic performance of axial-flow pumps under different flow conditions, especially at low-flow conditions. As the flow rate decreased, the backflow velocity in near wall area of the inlet pipe and circumferential swirl velocity increased gradually, and the tip leakage vortex (TLV) and pressure surface vortex also increased gradually. Based on the average axial velocity V0 under the design flow rate, the axial backflow velocity was −1.18 V0 and the circumferential velocity was −3.53 V0 under the deep stall condition. The maximum vorticity of TLV, secondary vortex and pressure surface vortex was 5 × 106 S−2, and the area of maximum intensity was the largest. The interaction between the secondary vortices and the mainstream intensifies the formation and development of passage vortex and blocks the inlet pipe. Under the influence of comprehensive factors, the entropy production in the inlet channel and impeller region reached the maximum under the deep stall condition, both of which were above 22 × 10−2 kg m2 s−3 K−1, more than twice that outside the saddle zone. This study analyzed the flow instability under biased conditions from multiple levels and perspectives, providing a basis for improving the hydraulic performance under diverse flow conditions in the future.
GaN-based shallow-trench vertical Hall devices
Authors: Ma Kaiming , Huang Huolin , Sun Nan , Ding Nannan , Zuo Qingyuan , Shan Wenchao , Zhang Li , Lv Guohao , Dai Jianxun , Fu Deyi
Published: January 2025

In this Letter, a GaN-based vertical Hall device is designed and experimentally fabricated, offering an effective solution for in-plane magnetic field detection. By introducing a shallow trench structure between the excitation and sensing electrodes, the short-circuit current flowing into sensing contacts in GaN-based vertical Hall devices was strongly suppressed. Through TCAD simulation analysis, the optimal range of the shallow trench depth was determined, which was then confirmed by the experimental data. From the experimental results, the sensitivity was found to be improved by 4674.7%, from 3.8 to 177.6 mV/AT, while nonlinearity was reduced by 95.5%, from 19.17% to 0.87%. The effects of device width and sensing electrode length on the device performance were also investigated in detail. Finally, this work experimentally validated the device's angle detection capability, indicating that the GaN-based vertical Hall sensor could be combined with the currently well-established horizontal Hall sensors to create high-performance monolithic integrated three-dimensional Hall sensors.
High linearity and low hysteresis LMPs/MXene/AgNWs strain sensor for human motion detection
Authors: Zhang Jia-Rui , Li Ang , Sun Zhi-Juan , Wang Qiang , Zhang Yong-Lai , Han Dong-Dong
Published: January 2025

Resistive strain sensors show great potential in motion detection, medicine and healthcare, and human–machine interaction owing to their ease of fabrication, simple structure, and adjustable electrical performance. However, developing high-performance flexible resistive strain sensors with high sensitivity, high linearity, and low hysteresis remains a challenge. In this work, we report an LMPs (liquid metal particles)/MXene/AgNWs strain sensor (LMA strain sensor) with high sensitivity (GF = 6.339), high linearity (R2 = 0.982 24), and low hysteresis (0.452%). In this process, AgNWs act as a bridge between the MXene nanosheets, and the change in contact area of the MXene nanosheets under stretching endows the sensor with high sensitivity. The aggregated LMPs function as a structural framework, capitalizing on their intrinsic fluidic characteristics to serve as an adhesive between silver nanowires (AgNWs) and MXene nanosheets. This approach effectively minimizes the interstitial spaces between AgNWs and MXene. The formation of Ti-O → Ga3+ coordination bonds between MXene nanosheets and LMPs has strengthened the interfacial interactions. Consequently, the sensor demonstrates superior linearity and low hysteresis. In addition, a sensitive layer with a buckled structure is obtained by stretch-release. The buckled structure inhibits inhomogeneous and irreversible connection losses of the sensitive material, further improving the sensor's mechanical durability. LMA strain sensors can accurately detect various human activities such as breathing detection, motion detection, and expression detection. This work will provide an avenue for developing high-performance strain sensors.
Multiple and transforming vibrational identities of atoms in amorphous solids
Authors: Duan J. , Ding G. , Cai S. L. , Dai L. H. , Ma E. , Jiang M. Q.
Published: January 2025

Identifying the diverse roles of disorderly packed atoms inside an amorphous solid has been a highly pursued but daunting task in glass physics. By analyzing the full-frequency vibrational modes of a model Cu50Zr50 glass, here, we classify the internal atoms into low-, subhigh-, and high-frequency ones that have different tendencies for rearrangements upon excitations. We find that low-frequency atoms are structurally unfavored and tend to aggregate. High-frequency atoms originating from compressed atomic pairs are also mechanically unstable. As yield approaches, shear-transformation rearrangements shift from low-frequency to high-frequency atoms. Subhigh-frequency atoms play the role of stable backbones. Given that atoms can have different identities, multiple identities are observed to overlap in space. Atoms with one vibrational identity often transform to another one, showing different preferences in transformation routes. Our results deepen the understanding of atomic structures for amorphous plasticity beyond the simplified picture of soft vs hard spots.
Dynamic fracture toughness and fractal characteristics of crack in pressurized acidified Qinshui coal under impact loading
Authors: Gong Shuang , Sun Shiyi , Zhang Hansong , Zhang Yang , Wang Wen , Hao Xianjie
Published: January 2025

To investigate the effect of acid fracturing fluid on the fracture toughness and fractal properties of crack propagation in Qinshui coal under impact load, the 50 mm diameter split Hopkinson pressure bar device was employed to carry out mode I dynamic fracture toughness tests on Qinshui anthracite samples treated with acid fracturing fluid and water-based fracturing fluid under different impact pressures. Coal samples were subjected to force saturation and acidity treatment using an innovative apparatus. The fracture propagation phase of the specimen was acquired by a high-speed camera sensor. Combined with Image J analysis software and PCAS image recognition system, the macroscopic crack propagation trajectory and probability entropy of micro pores in coal samples were quantitatively analyzed. These findings revealed that dynamic fracture toughness endowed a strong rate-response relationship. When the impact pressure is 0.3, 0.4, and 0.5 MPa, the average fracture toughness of the water-based fracturing fluid group coal specimens was respectively 0.64, 1.20, and 1.31 times better that of the acidic fracturing fluid group. The rate of crack propagation and the dynamic fracture toughness of coal were reduced after acidification of the specimens. The crack growth rate initially surged, then decreased rapidly until it reached a stable state under impact load, while the variation in crack growth length and opening breadth showed a time-dependent increase. Crack propagation resistance and dynamic fracture toughness of coal are reduced by the acidification of the specimens. The fractal dimension of cracks in specimen increased under the impact of pressure growth. The fractal dimensions of crack in coal samples under the action of acidic fracturing fluid at 0.30, 0.40, and 0.50 MPa are 1.066, 1.078, and 1.087 times that of water-based fracturing fluid, as well as 1.119, 1.136, and 1.157 times that of natural state coal samples. With the increase in impact pressure, the entropy magnitude of the pore probability on the fracture surface of the coal sample also increased. The fracture surface morphology of coal sample transformed from compact and neat to loose and porous with the action of acidification. The dual mechanism of weakening and enhancing the fracture behavior of anthracite coal by fracturing fluid under different loading rates was explored, and a microscopic fracture mechanics model incorporating loading rate was developed based on the dual nature of the fracturing fluid and linear elastic fracture mechanics theory. The study results offer empirical evidence to investigate the process of fracture initiation and propagation in acid fracturing in Qinshui coal, and provide theoretical direction for designing acid fracturing in coal seams and controlling complicated fracture network.
Development of a displacement–kinetic hybrid vacuum pump
Authors: Xian Dongting , Li Xin
Published: January 2025

Rough vacuum is widely used in various fields such as industry, health care, and scientific research. Typically, rough vacuum pumps are mainly displacement pumps and kinetic pumps (also known as momentum transfer pumps). Due to their different working principles, the former generally suffers from severe issues like vibration and wear. Recently developed screw-type positive displacement pumps address these problems by utilizing high-precision meshing components. In contrast, kinetic pumps are less effective at achieving high vacuum levels. This paper introduces the design concept of a hybrid vacuum pump that combines both positive displacement and kinetic mechanisms. The hybrid vacuum pump generates pressure differences and fluid flow by driving high-speed rotating liquid, while variable volume is induced by changes in the liquid level, resulting in reduced pressure leading to gas suction. A theoretical model for the maximum suction pressure of the hybrid pump is developed in this paper, and the Δp–q characteristic curve of the hybrid pump is experimentally measured. The influence of low-pressure boiling phenomenon on the performance of the pump is also thoroughly examined.
Hanle spin precession induced inverted magnetoresistance in chiral/semiconductor systems
Authors: Tirion S. H. , van Wees B. J.
Published: January 2025

In the past decade, chiral materials have drawn significant attention because it is widely claimed that they can act as spin injectors/detectors due to the chirality-induced spin selectivity effect. Nevertheless, the microscopic origin of this effect is not understood, which generates the need for transport experiments that confirm the spin-dependent transport in chiral materials. Hanle spin precession measurements can unambiguously prove the injection and detection of a spin accumulation in a non-magnetic material, as was shown with traditional ferromagnetic injectors/detectors. Here, we model and analyze in detail the Hanle spin precession-induced magnetoresistance for chiral/semiconductor systems and find that the signal is inverted as compared to the ferromagnetic case. We explicitly model the spin injection and detection by both a chiral system and a ferromagnetic system, as well as the spin transport in a semiconductor, for a general set of (spin) transport parameters that cover the relevant experimental regime. For all sets of parameters, we find that the Hanle signals for a chiral system and ferromagnet are each other's opposites. We also discuss the implications for four terminal nonlocal spin transport experiments with separate chiral spin injector and detectors.
Microplastic presence in dried and fresh fish from seafood markets in Sri Lanka
Authors: Wootton Nina , Silva Vinuri , Giuretis Danielle , Reis-Santos Patrick , Gillanders Bronwyn M.
Published: January 2025

Context Microplastics have been found in aquatic ecosystems globally, including in many marine organisms. Despite this, understanding the occurrence of microplastics in seafood products prepared for human consumption has received less attention. Aims This study aims to determine the abundance and type of microplastic in dried and fresh fish purchased from seafood markets. Methods Four locally harvested species of anchovies and sardines were sampled from seafood markets across Sri Lanka. These pelagic species are popular seafood items and are commonly consumed whole. We analysed fresh (gastrointestinal tracts and whole body) and dried fish (whole body) under the microscope for microplastic presence (>38 μm, <5 mm), followed by polymer validation. Key results Across all fish sampled (N = 215), 82.3% had microplastic (3.64 ± 0.26 microplastics per individual), with fibre-shaped pieces making up more than 95% of all microplastic particles. Overall, contamination was higher in fresh fish than in whole dried fish. And, acrylic resin was the most common polymer. Conclusions Microplastics were found in nearly all fresh fish and almost half the dry fish from Sri Lanka, confirming the pervasive nature of microplastic contamination. Implications Differences in contamination levels in popular seafood products demonstrate how preparation and consumption habits can influence microplastic intake.
Expert navigators deploy rational complexity–based decision precaching for large-scale real-world planning
Authors: Fernandez Velasco Pablo , Griesbauer Eva-Maria , Brunec Iva K. , Morley Jeremy , Manley Ed , McNamee Daniel C. , Spiers Hugo J.
Published: January 2025

Efficient planning is a distinctive hallmark of intelligence in humans, who routinely make rapid inferences over complex world contexts. However, studies investigating how humans accomplish this tend to focus on naive participants engaged in simplistic tasks with small state spaces, which do not reflect the intricacy, ecological validity, and human specialization in real-world planning. In this study, we examine the street-by-street route planning of London taxi drivers navigating across more than 26,000 streets in London (United Kingdom). We explore how planning unfolded dynamically over different phases of journey construction and identify theoretic principles by which these expert human planners rationally precache decisions at prioritized environment states in an early phase of the planning process. In particular, we find that measures of path complexity predict human mental sampling prioritization dynamics independent of alternative measures derived from the real spatial context being navigated. Our data provide real-world evidence for complexity-driven remote state access within internal models and precaching during human expert route planning in very large structured spaces.
Spreading dynamics of information on online social networks
Authors: Meng Fanhui , Xie Jiarong , Sun Jiachen , Xu Cong , Zeng Yutian , Wang Xiangrong , Jia Tao , Huang Shuhong , Deng Youjin , Hu Yanqing
Published: January 2025

Social media is profoundly changing our society with its unprecedented spreading power. Due to the complexity of human behaviors and the diversity of massive messages, the information-spreading dynamics are complicated, and the reported mechanisms are different and even controversial. Based on data from mainstream social media platforms, including WeChat, Weibo, and Twitter, cumulatively encompassing a total of 7.45 billion users, we uncover a ubiquitous mechanism that the information-spreading dynamics are basically driven by the interplay of social reinforcement and social weakening effects. Accordingly, we propose a concise equation, which, surprisingly, can well describe all the empirical large-scale spreading trajectories. Our theory resolves a number of controversial claims and satisfactorily explains many phenomena previously observed. It also reveals that the highly clustered nature of social networks can lead to rapid and high-frequency information bursts with relatively small coverage per burst. This vital feature enables social media to have a high capacity and diversity for information dissemination, beneficial for its ecological development.
The functional role of oscillatory dynamics in neocortical circuits: A computational perspective
Authors: Effenberger Felix , Carvalho Pedro , Dubinin Igor , Singer Wolf
Published: January 2025

The dynamics of neuronal systems are characterized by hallmark features such as oscillations and synchrony. However, it has remained unclear whether these characteristics are epiphenomena or are exploited for computation. Due to the challenge of selectively interfering with oscillatory network dynamics in neuronal systems, we simulated recurrent networks of damped harmonic oscillators in which oscillatory activity is enforced in each node, a choice well supported by experimental findings. When trained on standard pattern recognition tasks, these harmonic oscillator recurrent networks (HORNs) outperformed nonoscillatory architectures with respect to learning speed, noise tolerance, and parameter efficiency. HORNs also reproduced a many characteristic features of neuronal systems, such as the cerebral cortex and the hippocampus. In trained HORNs, stimulus-induced interference patterns holistically represent the result of comparing sensory evidence with priors stored in recurrent connection weights, and learning-induced weight changes are compatible with Hebbian principles. Implementing additional features characteristic of natural networks, such as heterogeneous oscillation frequencies, inhomogeneous conduction delays, and network modularity, further enhanced HORN performance without requiring additional parameters. Taken together, our model allows us to give plausible a posteriori explanations for features of natural networks whose computational role has remained elusive. We conclude that neuronal systems are likely to exploit the unique dynamics of recurrent oscillator networks whose computational superiority critically depends on the oscillatory patterning of their nodal dynamics. Implementing the proposed computational principles in analog hardware is expected to enable the design of highly energy-efficient and self-adapting devices that could ideally complement existing digital technologies.
Symmetry facilitated the evolution of heterospecificity and high-order stoichiometry in vertebrate hemoglobin
Authors: Cortez-Romero Carlos R. , Lyu Jixing , Pillai Arvind S. , Laganowsky Arthur , Thornton Joseph W.
Published: January 2025

Many proteins form paralogous multimers—molecular complexes in which evolutionarily related proteins are arranged into specific quaternary structures. Little is known about the mechanisms by which they acquired their stoichiometry (the number of total subunits in the complex) and heterospecificity (the preference of subunits for their paralogs rather than other copies of the same protein). Here, we use ancestral protein reconstruction and biochemical experiments to study historical increases in stoichiometry and specificity during the evolution of vertebrate hemoglobin (Hb), an α
2
β
2
heterotetramer that evolved from a homodimeric ancestor after a gene duplication. We show that the mechanisms for this evolutionary transition were simple. One hydrophobic substitution in subunit β after the gene duplication was sufficient to cause the ancestral dimer to homotetramerize with high affinity across a new interface. During this same interval, a single-residue deletion in subunit α at the older interface conferred specificity for the heterotetrameric form and the
trans
-orientation of subunits within it. These sudden transitions in stoichiometry and specificity were possible because the interfaces in Hb are isologous, binding via the same surface patch on interacting subunits, but rotated 180° relative to each other. This architecture amplifies the impacts of individual mutations on stoichiometry and specificity, especially in higher-order complexes, and allows single substitutions to differentially affect heteromeric and homomeric interactions. Our findings suggest that elaborate and specific symmetrical molecular complexes may often evolve via simple genetic and physical mechanisms.
Behavioral nudges prevent loan delinquencies at scale: A 13-million-person field experiment
Authors: Kuan Robert , Blagg Kristin , Castleman Benjamin L. , Darolia Rajeev , Matsudaira Jordan D. , Milkman Katherine L. , Turner Lesley J.
Published: January 2025

Americans collectively hold over $1.6 trillion in student loan debt, and over the last decade millions of borrowers have defaulted on loans, with serious consequences for their financial health. In a 13-million-person field experiment with the U.S. Department of Education, we tested the effectiveness of different email interventions to inform borrowers about alternative repayment options after a missed loan payment. Our interventions tested whether sending monthly behaviorally-informed emails, providing follow-up reminders, framing benefits in percentage (vs. dollar) terms, and providing just one recommended action step at a time (vs. two) affected borrower outcomes. We find that i) behaviorally-informed emails reduce estimated 60-d delinquencies by 0.42 pp, ii) reminders boost the efficacy of such emails by 0.57 pp, iii) describing potential savings in percentage terms is more effective than describing these benefits in dollar terms, reducing estimated delinquencies by 0.14 pp, and iv) encouraging two actions (i.e., enrollment in income-driven repayment plans and auto debit programs) repeatedly across two emails is marginally more effective than encouraging one action at-a-time across two emails, reducing estimated delinquencies by 0.05 pp. Overall, if scaled to all 13-million borrowers in our experiment, we estimate that our best-performing intervention would have averted approximately 79,800 60-d delinquencies. Our findings i) highlight the benefits of describing potential savings in percentage terms, which may magnify perceived savings for recipients, ii) underscore the risks of oversimplification, and iii) demonstrate that nudges can be an effective, low-cost complement to other policies for reducing delinquencies and supporting borrowers with student loan debt.
Microfluidic purification of genomic DNA
Authors: Wang Jiayi , Butler Jason E. , Ladd Anthony J. C.
Published: January 2025

We describe a microfluidic device to extract DNA from a cell lysate, without the need for centrifuges, magnetic beads, or gels. Instead, separation is driven by transverse migration of DNA, which occurs when a polyelectrolyte solution flowing through a microfluidic channel is subjected to an electric field. The coupling of the weak shearing with the axial electric field is highly selective for long, flexible, charged molecules, of which DNA is the sole example in a typical cell lysate. As a result of migration to the walls, DNA is held near the channel inlet by electrophoresis (there is no flow near the channel walls), while the remaining components are eluted by the much larger (at least 10-fold) convective flow. We have demonstrated the feasibility of the device by recovering up to 40 ng of purified DNA in less than 30 min from 10
μ
L of
Escherichia coli
lysate. Gel electrophoresis indicates minimal additional fragmentation during purification, up to the maximum length recorded by the gel (60 kbp). Electropherograms were also obtained for purified mammalian DNA, using a Femto Pulse system (fragment lengths up to 165 kbp). Extracted samples show strong amplification by PCR, while the original lysate does not. Mixtures of
λ
-DNA and BSA were used to determine the extent of the separation of DNA from a physiological concentration of proteins (30 mg/mL). The protein concentration in the extract (0.3 to 0.5 ng/µL) was reduced by five orders of magnitude from the initial mixture.
Story alteration in oral history retellings
Authors: Mlynář Jakub , Kocián Jiří , Maliukov Hryhorii , Roginer Hofmeister Karin
Published: January 2025

The digitalization of oral history (OH) has resulted in the availability of multiple interviews conducted with the
same narrator under different circumstances. To explore the comparability of such materials, we analyze interviews with a
Holocaust survivor from the Fortunoff Video Archive (1979) and the Visual History Archive (1997), focusing on instances in which
she tells the “same” episode. We demonstrate that life-story segments before and after the episode provide clues for sense-making
and reflexively constitute the narrative environment. The specific interactional features of OH as a situated practice contribute
to the story’s recognizability and discursive alteration. Similarities and differences are detectable due to the coherence
established by the social setting of OH, including its availability in a digital archive, which guarantees comparability and
incorporates a broader chronology. The main contribution of our paper is methodological, as it outlines an apparatus for the
comparative analysis of OH across multiple databases.
‘Only’ a translator?
Authors: Svahn Elin
Published: January 2025

This article adopts a microhistorical approach, zooming in on the Swedish literary translator Lily Vallquist’s
(1897–1986) working life in the 1950s in relation to the professionalization of literary translators in Sweden during the same
period. Combining a microhistorical and translation sociological perspective, the article showcases how literary translators in
1950s Sweden engaged with different forms of boundary work to establish the literary profession as a profession in its own right
and how this is reflected in the everyday work by an individual translator. The correspondence with publishing house
representatives reveals that Lily Vallquist assumed a high degree of responsibility for different aspects of the translation
event; although she was “only” a translator, she was not “only translating”. In sum, the article challenges assumptions regarding
the multi-professionality of (literary) translators that are often presented as a universal truth and presents a case where the
translators rather strived for mono-professionalism.
An S-acylated N-terminus and a conserved loop regulate the activity of the ABHD17 deacylase
Authors: Holme Sydney , Sapia Jennifer , Davey Michael , Vanni Stefano , Conibear Elizabeth
Published: January 2025

The dynamic addition and removal of long-chain fatty acids modulate protein function and localization. The α/β hydrolase domain–containing (ABHD) 17 enzymes remove acyl chains from membrane-localized proteins such as the oncoprotein NRas, but how the ABHD17 proteins are regulated is unknown. Here, we used cell-based studies and molecular dynamics simulations to show that ABHD17 activity is controlled by two mobile elements—an S-acylated N-terminal helix and a loop—that flank the putative substrate-binding pocket. Multiple S-acylation events anchor the N-terminal helix in the membrane, enabling hydrophobic residues in the loop to engage with the bilayer. This stabilizes the conformation of both helix and loop, alters the conformation of the binding pocket, and optimally positions the enzyme for substrate engagement. S-acylation may be a general feature of acyl-protein thioesterases. By providing a mechanistic understanding of how the lipid modification of a lipid-removing enzyme promotes its enzymatic activity, this work contributes to our understanding of cellular S-acylation cycles.
Spacetime surgery for black hole fireworks
Authors: Lin Wei-Chen , Yeom Dong-han , Stojkovic Dejan
Published: January 2025

We construct an explicit model for the black hole to white hole transition (known as the black hole fireworks scenario) using the cut-and-paste technique. We model a black hole collapse using the evolution of a time-like shell in the background of the loop quantum gravity inspired metric and then the space-like shell analysis to construct the firework geometry. Our simple and well-defined analysis removes some subtle issues that were present in the previous literature [1] and makes the examination of the junction conditions easier. We further point out that the infalling and asymptotic observers, both in ours and the original scenario in ref. [1], encounter quite different physics. While the proper time of the bounce for an infalling observer can be determined without ambiguity, the bouncing time interval for the asymptotic observer can be chosen arbitrarily by changing how one cuts and pastes the spacetimes outside the event horizons. It is puzzling that the proper time of a distant (rather than infalling) observer is subject to randomness since the infalling observer is supposed to experience a stronger quantum gravity effect. This result might suggest that a black hole firework scenario does not allow for the existence of an effectively classical spacetime inside the horizon. The main message is therefore that even if we strictly follow the thin shell formalism to cut and paste spacetimes, this does not guarantee that the resulting spacetime offers a physically reasonable background.
Distinct photon-ALP propagation modes
Authors: Cao Qing-Hong , Liu Zuowei , Wang Jun-Chen
Published: January 2025

Measurement of cosmic photons may reveal their propagation in the interstellar
environment, thereby offering a promising way to probe axions and axion-like particles (ALPs).
Numerical methods are usually used to compute the propagation of the photon-ALP beam due to the
complexity of both the interstellar magnetic field and the evolution equation. However, under
certain conditions, the evolution equation can be greatly simplified so that the photon-ALP
propagation can be analytically solved. By using analytic methods, we find two distinct
photon-ALP propagation modes, determined by the relative magnitude of the photon-ALP mixing term
in comparison to the photon attenuation term. In one mode, the intensity of photons decreases
with the increasing distance; in the other mode, it also exhibits oscillatory behavior. To
distinguish the two propagation modes, we compute the observable quantities such as the photon
survival probability and the degree of polarization. We also determine through analytic methods
the conditions under which maximum polarization can be observed and the corresponding upper bound
of the survival probability.