Mutual Interaction Research Articles

Russian-Croatian trade relations in current environment of sanctions

Aim. To assess the impact of Western European sanctions on Russian-Croatian trade relations in 2020-2023 and Croatian tourism sector.Objectives. To analyze the dynamics of key indicators of trade between the Russian Federation (RF) and Croatia under sanctions; to identify the main commodity groups in the structure of their trade; to determine the importance of Russia for the tourism sector of the Republic of Croatia.Methods. The author used such research methods as statistical analysis, generalization, description and graphical modeling.Results. The results obtained in the process of the analysis indicate a sharp decline in the volume of mutual trade of the Russian Federation with Croatia in the conditions of numerous trade restrictions from the European Union. In 2023, the commodity structure of Russian exports to the Republic of Croatia has changed significantly, the basis of Russian exports is now made up of finished goods and goods of the chemical industry. The flow of tourists from Russia occupies an insignificant share in the total tourist flow of Croatia and has little impact on the tourism sector of the Republic. Under the conditions of the sanctions regime, Croatian companies have begun to cease economic activities in the territory of the Russian Federation.Conclusions. The current situation on the world stage has determined the dynamism of mutual trade interaction between Russia and Croatia. Thus, the sanctions imposed by the countries of the collective West have a negative impact on Russian-Croatian relations both in trade and tourism. The tendencies of reduction of mutual trade and tourist flows have a long-term character and negative dynamics of interaction between the two countries. Normalization of trade relations between Russia and Croatia in the geopolitical situation today seems unlikely.

Impurity convection reversal caused by edge localized turbulence for generating a stationary edge radiative layer in the HL-2A tokamak

Abstract Effect of impurity on edge turbulence was investigated on the HL-2A tokamak by using Neon supersonic molecular beam injection (SMBI). For the first time, a stationary radiative layer accompanied by edge localized turbulence lasting more than 100ms is observed at the edge region ρ=0.7-0.9. This duration is much longer than the SMBI pulse length (1.2ms), indicating that the impurity diffusion is on the whole cancelled out by the impurity convection without spreading of the localized turbulence during this period. This implies that the impurity convection is reversed from positive to negative impurity density gradient region. This reversal could be explained by the parallel impurity compression mechanism. The observed turbulence is a broadband electrostatic turbulence (25-70 kHz) propagating in the electron diamagnetic drift direction with normalized poloidal wavenumber of 0.1≤ kθρs≤0.4. It has been found that the excitation of the edge localized turbulence strongly depends on the local collisionality. This feature is qualitatively predicted by the spectral multiscale gyrokinetic turbulence simulation, which suggests that the turbulence could be a dissipative trapped electron mode (DTEM). This experiment demonstrates that mutual interaction between externally injected impurity ions and edge turbulence can generate a stationary edge radiative layer and avoid impurity core accumulation. These results could provide a potential approach for the formation of a stable impurity radiative layer by impurity injection in tokamaks.

Intraspecific plant chemodiversity at the individual and plot levels influences flower visitor groups with consequences for germination success

Abstract Chemodiversity, the diversity of specialised (secondary) metabolites, plays a crucial role in mediating interactions between plants and animals, including insect herbivores and mutualists. Chemodiversity can be observed at both the individual and the population level. However, the impacts of chemodiversity at these two levels on interactions between plants and floral visitors, mainly pollinators and floral herbivores (florivores), are only poorly understood. This study aimed to investigate the effects of chemodiversity at both individual (chemotype) and plot level on pollinators and florivores, examining their mutual interactions. To investigate these questions, we used individuals of the perennial Tanacetum vulgare differing in their terpenoid composition, representing different chemotypes. We planted individuals of five distinct chemotypes in a common garden design with homogeneous (five plants of the same chemotype) and heterogeneous (five different chemotypes) plots and observed flower visits in dependence of individual chemotype and plot type. Seeds were collected from a subset of plants and germination rates determined. Our findings revealed that chemodiversity at the plot level significantly influenced pollinator visitation, with more visits on plants of heterogeneous plots. We also observed marginally more pollinators on one of the chemotypes grown in homogeneous plots. In contrast, chemotype but not plot type had a significant effect on florivore visits. Pollinator and florivore species richness did not vary with plot type. Furthermore, a negative correlation was observed between pollinator and florivore visits in 1 year. Germination rates were positively correlated with pollinator visits and affected by chemotype but not by florivore visits or plot type. Synthesis. Our study emphasises the significance of the spatial level at which plant chemistry is perceived by flower visitors, potentially influencing the germination success of plants. Exploring the ecology of these visitors and the varying selection pressures they exert on floral chemistry can help to elucidate the evolutionary processes that maintain chemodiversity in natural environments. Read the free Plain Language Summary for this article on the Journal blog.

Distribution of quantum gravity induced entanglement in many-body systems

Abstract Recently, it was shown that if two distant test masses, each in a spatially superposed quantum state, become entangled due to their mutual gravitational interaction, then this entanglement could serve as evidence of the quantum nature of gravity We extend this treatment to a many-body system in a general setup and study the entanglement properties of the time-evolved state. We exactly compute the time-dependent I-concurrence for every bipartition and obtain the necessary and sufficient condition for the creation of genuine many-body entanglement. We further show that this entanglement is of generalised GHZ type when certain conditions are met. We also evaluate the amount of multipartite entanglement in the system using a set of generalised Meyer-Wallach measures.

On-Demand Coalescence of Ferromagnetic Droplets in Microchannels Using an Oscillating Magnetic Field.

Droplet-based microfluidics exhibit remarkable potential in achieving high-throughput chemical reactions with minimal reagent consumption. However, a pivotal challenge lies in the selective coalescence of droplets for precise process control, particularly when dealing with droplets of varying amounts and volumes, which are difficult to trap and coalesce due to their tiny dimensions and incessant movement. Hence, we proposed a method for on-demand coalescence of ferromagnetic droplets using an oscillating magnetic field. Experimental results show that the ferromagnetic droplets can be trapped in different positions in the microchannels according to the applied magnetic field intensity. A high-intensity pulsed amplitude of the magnetic field enables the migration of trapped droplets toward the same position, facilitating their mutual contact and interaction. By programmable modulation of the oscillating magnetic field, a controllable reciprocation of droplets in microchannels was successfully realized, which enabled us to dynamically capture, coalesce, and release two or more (≥3) droplets on demand. The integrated ferromagnetic droplet-based microfluidic platform allows contact-free, easily monitored, and on-demand coalescence of ferromagnetic droplets in microchannels, which holds promise for a wide range of applications, such as microfluidic-based drug synthesis, biosensing, reaction kinetics, and paracrine signaling, particularly.

How relevant is the relationship between ostiole size and wasp head shape in the Ficus-Agaonidae mutualistic interaction?

The mutualism between Ficus species (Moraceae) and their pollinating wasps (Agaonidae) is a widely recognized coevolutionary model. In Ficus species from the Paleotropic, it has been determined that the ostiole acts as a morphological filter that affects the head dimensions of pollinating female wasps. Here, for the first time, the allometric relationship between ostiole size (diameter and length) and the shape of the head (length/width) of pollinating wasps is quantitatively explored in 6 Neotropical Ficus species (3 sect. Americanae and 3 sect. Pharmacosycea). In the case of sect. Americanae, wasp head shape was significantly correlated only with ostiole length, while in sect. Pharmacosycea both ostiole variables were correlated with head shape. The ordination analysis (NMDS) clearly reflected associations of these traits in species for both sections. The results support what has been interpreted in previous studies as reciprocal evolution between the analyzed traits, which contribute, along with other morphological and ecological traits, to the specificity between Ficus species and their pollinating wasps.

Urbanization drives partner switching and loss of mutualism in an ant-plant symbiosis.

Mutualistic interactions between species underpin biodiversity and ecosystem function, but may be lost when partners respond differently to abiotic conditions. Except for a few prominent examples, effects of global anthropogenic change on mutualisms are poorly understood. Here we assess the effects of urbanization on a symbiosis in which the plant Cordia nodosa house ants in hollow structures (domatia) in exchange for defense against herbivores. We expected to find that mutualist ants would be replaced in the city by heat-tolerant opportunists, leaving urban plants vulnerable to herbivory. In five protected forest sites and five urban forest fragments in southeast Perú, we recorded the identity and heat tolerance (CTmax) of ant residents of C. nodosa. We also assayed their plant-defensive behaviors and their effects on herbivory. We characterized the urban heat-island effect in ambient temperatures and within domatia. Forest plants housed a consistent ant community dominated by three specialized plant ants, whereas urban plants housed a suite of 10 opportunistic taxa that were, collectively, about 13 times less likely than forest ants to respond defensively to plant disturbance. In the forest, ant exclusion had the expected effect of increasing herbivory, but in urban sites, exclusion reduced herbivory. Despite poor ant defense in urban sites, we detected no difference in total standing herbivory, perhaps because herbivores themselves also declined in the city. Urban sites were warmer than forest sites (daily maxima in urban domatia averaged 1.6°C hotter), and the urban ant community as a whole was slightly more heat tolerant. These results illustrate a case of mutualism loss associated with anthropogenic disturbance. If urbanization is representative of increasing anthropogenic stressors more broadly, we might expect to see destabilization of myrmecophytic mutualisms in forest ecosystems in the future.

Understanding delusions to improve our mutual interactions: A précis of <i>"Why Delusions Matter"</i>

Why Delusions Matter is a reflection on the importance of the study of delusions for better understanding and reshaping our mutual interactions. The study of delusions has transformed the philosophy of mind and psychology in the last thirty years, helping redefine the relationship between rationality and intentionality. It has still a lot to offer to emerging areas at the intersection of ethics and epistemology. These are areas where the focus of the investigation of beliefs is moving from a painstaking assessment of the individual’s cognitive achievements and failures to a broader examination of the environmental and social pressures on the adoption, revisions, and maintenance of beliefs at individual and collective levels. In the book, there is an exploration of the notion of delusionality across clinical and non-clinical contexts which shows how delusions are meaningful beliefs that matter to the speaker's identity but are received by the interpreter as implausible and unshakeable. Delusions are not pathological by default, but they can bring epistemic and psychological costs as well as temporary benefits. Although a speaker's delusions can make collaboration difficult, this should not discourage interpreters from attempts at genuine engagement. Delusions are not a sign of a breakdown in the speaker's capacity for agency and thus understanding them can help interpreters appreciate the speaker's perspective.

Vegetative traits, floral biology, and mutualistic interactions in the tropical mountain shrub Ribes ciliatum (Grossulariaceae)

Plant species in tropical mountain ecosystems experience significant environmental variation across short spatial distances. These systems offer an opportunity to assess geographic variation in plant traits in relation to biotic and abiotic environments. We examined plant vegetative and reproductive traits in the shrub R. ciliatum across two native conifer forests in central Mexico. We measured plant height, number of branches, leaf size, flower production, floral morphology, floral longevity, and plant reproductive success in R. ciliatum populations found in fir forests (3100 m) and Hartweg's pine forests (subalpine habitat, 3700 m). We also quantified the level of pollinator dependence, pollinator visitation rates, and fruit consumption rates by frugivorous birds in both populations. Plants were shorter and had smaller leaves in the subalpine forest than in the fir forest. Floral longevity decreased in the subalpine forest, but flower production, flower size, and fruit weight remained similar across populations. Fruit set and pollinator visitation rates were higher in the subalpine forest; however, seed weight and fruit consumption rates did not differ between sites. Hummingbirds and bumblebees were the primary pollinators of R. ciliatum, and the bird Ptiliogonys cinereus was the most important fruit consumer at both sites. Fruit set was entirely dependent on pollinators. Reduced plant size in the subalpine forest coincides with a general pattern associated with high mountain environments. In contrast, reproductive characters had a closer relationship to the pollination environment. The absence of variation in flower size and shape was consistent with the similarity in the composition of the pollinator community. Meanwhile, compared to lower-elevation forests, the subalpine forest exhibited shorter-lived flowers and increased fruit set, associated with higher pollinator visitation rates. Ribes ciliatum is a key resource for pollinators and frugivores at a time of year when few other floral resources are available in these high-elevation mountain forests.

Bose Metals, from Prediction to Realization.

Bose metals are metals made of Cooper pairs, which form at very low temperatures in superconducting films and Josephson junction arrays as an intermediate phase between superconductivity and superinsulation. We predicted the existence of this 2D metallic phase of bosons in the mid 1990s, showing that they arise due to topological quantum effects. The observation of Bose metals in perfectly regular Josephson junction arrays fully confirms our prediction and rules out alternative models based on disorder. Here, we review the basic mechanism leading to Bose metals. The key points are that the relevant vortices in granular superconductors are core-less, mobile XY vortices which can tunnel through the system due to quantum phase slips, that there is no charge-phase commutation relation preventing such vortices from being simultaneously out of condensate with charges, and that out-of-condensate charges and vortices are subject to topological mutual statistics interactions, a quantum effect that dominates at low temperatures. These repulsive mutual statistics interactions are sufficient to increase the energy of the Cooper pairs and lift them out of condensate. The result is a topological ground state in which charge conduction along edges and vortex movement across them organize themselves so as to generate the observed metallic saturation at low temperatures. This state is known today as a bosonic topological insulator.

Attachment Anxiety, Marital Adjustment and Psycho-Social Support of Love and Arranged Marriages Among Meranao Women

This study aims to explore the level of attachment anxiety, marital adjustment, pyscho-social support of love and arranged marriages among Meranao women specifically, it sought to answer the following questions: 1.What is the demographic profile of the respondents in love marriage and arranged marriages in terms of present age, age at the time of marriage, family monthly income, number of children and sibling rank? 2. What is the level of attachment related anxiety, the marital adjustment of the respondents in love and arranged marriages among the following aspects psychological, social, emotional and spiritual? 3. What are the marital adjustment of the respondents in love and arranged marriages when classified as social, physical, financial and spiritual? 4. What is the level of marital quality of the respondents in love and arranged marriages on the following aspects; commitment, trust and mutual interaction? 5. What are the forms of marital support of the respondents in love and arrange marriages receive in terms of psychological, confidant, affective and social support? 6. How do love marriages differ from arranged marriages along the following along the following aspects; level of attachment anxiety, marital adjustment, level of marital quality and marital support? 7. What marriage counseling program has been developed on the basis of the findings of the study. This study was conducted at Tuca, Pindolonan and Dawayan, Marawi City with the total number of 327 married Meranao women, with a breakdown of 132 for love marriage and 195 for arranged marriage. The researcher utilized the descriptive–correlation design. Part of study was done through describing the demographic profile of the respondents and personal profile in terms of age, gender, socio economic status, educational attainment, monthly income and occupation. Their perceptions on their marriage particularly on attachment anxiety, marital adjustment, marital quality and marital support were also given descriptions. On the other hand, these two important variables were then correlated so as to establish a conclusion that a wife’s profile can affect her perception on her marriage life.

Stability of slender GFRP tube-confined UHPC-filled steel-encased column under axial compression: Experiment and mesoscale modeling

The stability of GFRP tube-confined UHPC-filled steel-encased columns (FUSCs) is critical for optimal utilization of its superior cross-sectional load-bearing capacity that guarantees overall structural safety. This study conducted an experimental investigation on 14 slender FUSC specimens under uniaxial compression for different aspect ratios and aggregate contents. The pressure-sensing films were applied to measure the contact pressure between the GFRP tube and UHPC, and a mesoscale finite element model was developed to uncover the role of randomly distributed fibers and aggregates in the UHPC during the failure process. Accordingly, the stability performance of slender FUSC was analyzed, and specific discussions were held on the mutual interaction mechanism between GFRP and UHPC during the loading process. The results showed that the stability of FUSCs decreased faster with an aspect ratio of l0/D > 8 (λ>30.77), resulting in the decrease of load-carrying capacity for up to 25 %. By including coarse aggregate, the distribution of steel fibers was densified, and Young's Modulus of UHPC was increased, considerably improving the stability of FUSCs. Moreover, the GFRP tube with a fixed winding angle of 50° remarkably enhanced the stability of the specimen due to the sharing of bending moment instead of providing confinement. This research outcome offers a basis for the stability control of slender FUSCs.

A comprehensive propulsion system analysis: an integrated approach utilising engine simulation and free-running model experiments

Regulations concerning the environmental impact and energy efficiency of ships are becoming increasingly stringent. To meet these demanding criteria, new technologies are actively being developed to achieve emission reductions while maintaining efficient fuel energy conversion into propulsion power. However, the propulsion system behaviour in a dynamic environment of the actual sea is highly nonlinear and complex, and a profound understanding of the mutual interactions is still lacking. This paper proposes an integrated approach for comprehensive propulsion system analysis. The key feature of this technique is the utilisation of an intelligent propeller drive controlled by a marine diesel engine simulator (MDES) to drive the free-running model of a ship, providing real-like behaviour of the engine model in real-time in response to actual measured values. The core of the MDES consists of a continuous cycle-mean value dynamic engine model supplemented with a detailed combustion cycle evaluation. The developed fast calculation algorithm of crank-angle resolved thermodynamic equations of the gas state in the engine cylinder enables the complete engine model to be integrated into the real-time environment of a physical model ship. Thus, the propulsion system's performance can be analysed under conditions that closely mimic those of the actual sea environment.

Rethinking science diplomacy and global biosecurity: challenges, emerging practices and the way forward

Abstract The changing organization and nature of biotechnology and bio-innovations have led to the global phenomenon of ‘science at large’. This has given rise to two key trends in global biosecurity governance: the growing role of science diplomacy in addressing biosecurity concerns and the rise of distributed agencies, particularly involving young practitioners from the global South, who are participating in a decentralization of western-dominated biosecurity discourse through Track II science diplomacy. These trends require updated and inclusive regulatory innovations that acknowledge biosecurity and related regulatory-ethical discussions as crucial elements of public diplomacy. There is a particular need to align these efforts with emerging forms of societal funding and to foster novel public–private partnerships in advanced bioscience research. They also call for promoting multitrack science diplomacy by bolstering institutional support for science diplomacy and biosecurity. This could be in the form of dedicated funding, or the establishment of sustained platforms to enable regular mutual learning and interactions between an international group of scientists and policy-makers. These efforts should be complemented by investment to normalize cross-disciplinary and cross-sectoral dialogues, which are essential for building communities among both established and new stakeholders. These dialogues can foster mutual learning, cultural harmonization and the development of joint initiatives to address shared biosecurity concerns. This policy paper advocates for the formal integration of science diplomacy training into university science curriculums, especially at the postgraduate level. This training will equip the next generation of scientists to align scientific visions and enhance biosecurity compliance in an increasingly connected yet ideologically diverse world.

Facilitators or predators? The role of seed-feeding beetles in the germination of an ornamental and invasive plant in an urban environment

Leucaena leucocephala is a forage legume that provides cellulose, firewood, and shade in cities, although it presents a dangerous allelopathic and invasive potential. Its main natural enemy is the endophytic beetle Acanthoscelides macrophthalmus (Chrysomelidae: Bruchinae), whose larvae penetrate seeds and can consume the entire endosperm and embryos. However, there is much to explore on how the abundance of larvae inside the seed affects the plant germination, resulting in an antagonistic (predation) or mutualistic (facilitation) interaction. Our goal was to test how these beetles affect the germination of L. leucocephala seeds from an urban environment in Uberlândia, MG. We hypothesized that a single larva inside the seed facilitates germination since the exit holes left break the physical dormancy and enable water imbibition. On the other hand, two or more larvae inside the same seed result in predation, as the amount of endosperm is not enough for beetle satiation before they attack the seed embryo. We collected 100 pods, dissected them, and quantified and qualified the seeds. In the germination experiment, we used healthy seeds (control), scarified healthy seeds (physical treatment), and attacked seeds (one, two, or more larvae). We found that beetles infested 74% of the sampled seeds. Independently of the abundance of larvae inside the seed, attacked seeds did not germinate. The scarified seeds germinate faster and in greater quantity. Therefore, our hypothesis was rejected for the studied plant population. Acanthoscelides macrophthalmus acts only as a predator in an antagonistic interaction that decreases the germination rate of L. leucocephala.

Attached and suspended biomass kinetics in an IFAS-MBR system operated under intermittent aeration: Long-term monitoring under SRT variation

This study thoroughly investigates a Membrane BioReactor – Integrated Fixed Film Activated Sludge – Intermittent Aeration (MBR-IFAS-IA) pilot plant operated from a biokinetic point of view. Specifically, respirometric techniques were applied on suspended and attached biomass to evaluate kinetic and stoichiometric parameters. The main aim was to investigate how the simultaneous presence of biofilm and activated sludge could affect the kinetic behaviour and the role of the Sludge Retention Time (SRT) variation in the kinetic behaviour of the system. The results highlighted a mutual interaction between suspended biomass and biofilm in the IFAS-MBR configuration. In Period I both the heterotrophic yield and growth rate of suspended biomass were higher compared to that of biofilm, thus highlighting higher affinity with organic matter; in contrast, the biofilm showed high affinity with nitrification, with increased nitrification rates with decreasing SRT and sustaining nitrification in the activated sludge due to “seeding” effect. Therefore, the suggestion is that it is possible to operate IFAS-MBR systems at low SRT without hampering the nitrification ability due to the growth of nitrifiers in the biofilm. Respirometry has been confirmed to be an effective tool for evaluating biomass kinetic and stoichiometric parameters. The results of this study highlighted the effect of IFAS configuration and can help apply mathematical models in the design phase and monitor biomass viability during plant operations.

Exploring chemical reactivity through a combined conceptual DFT and ELF topology approach.

In a proof-of-concept study, we explore how a combined approach using the topology of the electron localization function (ELF) and the condensed dual descriptor (DD) function can guide the optimal orientation between reactants and mimic the potential energy surfaces of molecular systems at the beginning of the chemical pathway. The DD has been chosen for its ability to evaluate the regioselectivity of neutral and soft species and to potentially mimic the interaction energy obtained from the mutual interactions between nucleophilic and electrophilic regions of the building blocks under perturbative theory. Our method has been illustrated with examples in which the optimal orientation of several systems can be successfully identified. The limitations of the presented model in predicting chemical reactivity are outlined in particular the influence of the selected condensation scheme.

Effects of foundation pit excavation on adjacent metro stations and shield tunnel structures: a study on horizontal displacement

PurposeThe aim of this study is to investigate the horizontal displacement effects of foundation pit excavation on adjacent metro stations and shield tunnel composite structures. It seeks to develop a theoretical calculation method capable of accurately assessing these engineering impacts, aiming to provide practical assistance for engineering applications.Design/methodology/approachThis study introduces a model for shield tunnel segments incorporating rotation and misalignment, considering the constraints of metro stations. It establishes a displacement model for tunnel-station combinations during foundation pit excavation, deriving a formula for calculating station-proximal tunnel horizontal displacements. The method's accuracy is validated against field data from three engineering cases. The research also explores variations in tunnel displacement, inter-ring shear force, misalignment and rotation angle under different spatial relationships between pits, tunnels and stations.FindingsThis study models uneven deformation between stations and tunnels due to bending stiffness and shear constraints. It enhances the misalignment model with station-induced shear effects and introduces coefficients for their mutual interaction. Results show varied responses based on pit-station-tunnel positioning: minimal displacement near pit edges (coefficients around 0.1) and significant effects near pit centers (coefficients from 0.4 to 0.5). “Whip effect” from station constraints affects tunnel displacement, shear force, misalignment and rotation, with fluctuations decreasing with distance from excavation areas.Originality/valueThis study demonstrates significant originality and value. It introduces a novel displacement model for tunnel-station combinations considering station constraints, addressing theoretical calculations of horizontal displacement effects from foundation pit excavation on metro stations and shield tunnel structures. Through validation with field data and parameter studies, the concept of influence coefficients is proposed, offering insights into variations in structural responses under different spatial relationships. This research provides crucial technical support and decision-making guidance for optimizing designs and facilitating practical construction in similar engineering projects.

Numerical Simulation of Fixed-Free End Beam’s Modal Behaviour using Two-Way Coupled Fluid-Structure Interaction Approach

The fluid flow velocity stands as a pivotal parameter with a great influence on the mutual interaction between the fluid domain and structure. This paper focuses on structural deformation, structural velocity, von-Mises stress and frequency response of a fixed-free end beam using two-way coupled fluid-structure interaction within ANSYS Workbench. The parameters such as deformed fluid pressure and velocity were analysed across three diverse flow regimes: laminar, transitional and turbulent – each aligned with distinct fluid velocities. The outcomes show that the total deformation, velocity and von-Mises stress distribution of the fixed-free end beam increase as the inlet fluid velocity increases. As a result, the pressure and velocity distribution in the fluid flow which receiving the resultant or leftover structure deflection also increases as the incoming fluid velocity increases. Furthermore, the analysis probes the frequency response in turbulent flow conditions reveals higher values compared to laminar and transitional flows, albeit within the same natural frequency domain. This observation marks significant vibrational characteristics found in the presence of turbulent flow dynamics.

Decoding the temporal structures and interactions of multiple face dimensions using optically pumped magnetometer magnetoencephalography (OPM-MEG).

Humans possess a remarkable ability to rapidly access diverse information from others' faces with just a brief glance, which is crucial for intricate social interactions. While previous studies using event-related potentials/fields have explored various face dimensions during this process, the interplay between these dimensions remains unclear. Here, by applying multivariate decoding analysis to neural signals recorded with optically pumped magnetometer magnetoencephalography (OPM-MEG), we systematically investigated the temporal interactions between invariant and variable aspects of face stimuli, including race, gender, age and expression. First, our analysis revealed unique temporal structures for each face dimension with high test-retest reliability. Notably, expression and race exhibited a dominant and stably maintained temporal structure according to temporal generalization analysis. Further exploration into the mutual interactions among face dimensions uncovered age effects on gender and race, as well as expression effects on race, during the early stage (around 200-300 ms post face presentation). Additionally, we observed a relatively late effect of race on gender representation, peaking around 350 ms after stimulus onset. Taken together, our findings provide novel insights into the neural dynamics underlying the multi-dimensional aspects of face perception and illuminate the promising future of utilizing OPM-MEG for exploring higher-level human cognition.Significance statement In everyday social activities, people can quickly interpret a wide range of information from others' faces. Although converging evidence has shed light upon the neural substrates underpinning the perception of invariant and variable aspects of faces, such as race, gender, age and expression, it is still not fully understood how the information of one face dimension alters the perception of another. In this study, we utilized multivariate decoding analysis on neural activity captured through OPM-MEG during face perception. Our approach enabled a comprehensive exploration of the temporal interactions among different face dimensions, providing an improved understanding of the temporally structured neural dynamics that support the multi-dimensional face perception in the human brain.