Frequency Of Exchanges Research Articles

Le développement des interactions sociales d’enfants avec trouble du spectre de l’autisme dans une unité d’enseignement en maternelle

ObjectivesInclusive preschool classrooms have been recently created (since 2014) in France for children with Autism Spectrum Disorder, giving them access to regular schools while adjusting to their specific needs. In these preschool small units, educative and mental health staff work together to support children's communicative and learning skills in order to help them to progressively attend regular classes in the same school. International research has reported the benefits of inclusive education on children with ASD, but studies mainly concerned children in full inclusion in regular classrooms, whose constraints, even with adapted programs, may not be suitable for all of them, especially young children. Moreover, studies conducted in specialized as well as in regular classrooms showed that the frequency and functional quality of the children's communicative exchanges may greatly vary, depending on the interlocutor and on the requirements of school situations (structured or unstructured). In this paper, we present a longitudinal study about communication development from age three to six in children with ASD attending an inclusive preschool program. On the basis of direct observations of situations filmed in class, variations of social communication were systematically examined as a function of partners (adults vs. peers), degree of structuration (work vs. free play), and over time. MethodsParticipants were seven children with ASD, aged 3 at the beginning of the study and attending the same preschool inclusive unit. They were regularly videotaped (twice a year during three years) in two types of classroom situations: structured (working) and unstructured (free play), interacting with adults and peers. Data reported here are for the comparison between the first and the last collection point (three years vs. six years). Videos were coded using a structured microanalysis grid to capture the quality (forms and functions) of social and communicative behaviors of children and of their partners. In parallel, standardized evaluations were conducted on children's clinical and developmental characteristics. ResultsData analysis showed a differentiated progression in quantity and quality of communication observed in preschool inclusive classrooms according to contextual parameters. Children's social-communicative engagement was generally more frequent in structured than unstructured activities, but initiations progressed over time in unstructured activities. Children interacted much more often with adults than with peers, with no significant increase in this gap over the years. The quality of children's communication improved both in forms and functions, but to varying degrees depending on the context. During structured activities, children became more able to use multimodal coordination (e.g., verbal/nonverbal) within the same communicative act while during unstructured activities they more often use one modality communicative acts. Concerning the purpose of interactions, children most often communicate for instrumental purposes than for social sharing purposes, a difference that persisted over time. A single subject analysis revealed important variations in pace and extent of developmental change between three and six years, with an increased progression observed in children with initial higher social and cognitive developmental levels. ConclusionsFindings are discussed in the perspective of optimizing the implementation of inclusive preschool educative settings for children with ASD. In particular, three points seem to deserve reinforced support: (a) to promote opportunities for children's initiatives in addition to soliciting responses; (b) to enhance the opportunities for social sharing; (c) to support peer-to-peer interactions during play or work co-activities.

Manifestations of static and dynamic heterogeneity in single molecule translational measurements in glassy systems.

Rotational-translational decoupling in systems near Tg, in which translational diffusion is apparently enhanced relative to rotation, has been observed in ensemble and single molecule experiments and has been linked to dynamic heterogeneity. Here, simulations of single molecules experiencing homogeneous diffusion and static and dynamic heterogeneous diffusion are performed to clarify the contributions of heterogeneity to such enhanced translational diffusion. Results show that time-limited trajectories broaden the distribution of diffusion coefficients in the presence of homogeneous diffusion but not when physically reasonable degrees of static heterogeneity are present. When dynamic heterogeneity is introduced, measured diffusion coefficients uniformly increase relative to input diffusion coefficients, and the widths of output distributions decrease, providing support for the idea that dynamic heterogeneity can drive apparent translational enhancement. Among simulations with dynamic heterogeneity, when the frequency of dynamic exchange is correlated with the initial diffusion coefficient, the measured diffusion coefficient behavior as a function of observation time matches that seen experimentally, the only set of simulations explored in which this occurs. Taken together with experimental results, this suggests that enhanced translational diffusion in glassy systems occurs through dynamic exchange consistent with wide underlying distributions of diffusion coefficients and exchange coupled to local spatiotemporal dynamics.

Evaluation of sister chromatid exchange in patients with breast cancer in relation to clinical stage

High levels of sister chromtid exchanges (SCE) in patients with breast caner reflects a genomic instability that may be operative in carcinogenesis.The frequency of sister chromatid exchanges in peripheral blood lymphocytes was analyzed in patients with breast cancer in relation to clinical stage in 12 stage II and 5 Stage IV untreated breast cancer patients.Moreover,SCE baseline values in patients were compared with a control group of 12 healthy women. A significant difference emerged between patients and control (P<0.01).SCE increased significantly in stage IV breast cancer patients compared with those patients of stage II (P<0.05).The results reveal that SCE frequency increases with the progression of clinical stage of breast cancer.

Understanding the transport networks complex between South Asia, Southeast Asia and China during the late Neolithic and Bronze Age

The emergence and intensification of transcontinental exchange during both the Late Neolithic and Bronze Age profoundly influenced the social history of Eurasia. While scholars have intensively discussed east-west long-distance communication along the proto-Silk Road, the north-south transport networks that connected China to South and Southeast Asia during the Late Neolithic and Bronze Age have attracted much less attention in the scholarly literature based on archeological science data. In this paper, we find new radiocarbon dates from 11 Neolithic and Bronze Age sites in northwestern and central Yunnan in Southwest China, a key entrance into South and Southeast Asia from China. Combined with previously published archeological records and radiocarbon dates, we attempt to disentangle and understand the timing and routes of the networks linking China to South and Southeast Asia during the Late Neolithic and Bronze Age. We propose three north-south land routes that played essential roles in the cultural exchanges in addition to the proto-Silk Road and maritime routes. This includes the trans-Himalayan routes, trans-Hengduan Mountain routes, and the trans-Yunnan–Guizhou Plateau routes. The north-south exchange between China and South and Southeast Asia probably emerged in the fifth millennium BP (before the present) mainly through a low-frequency trans-Yunnan–Guizhou Plateau and trans-Himalayan routes. The exchange frequency significantly increased after the fourth millennium BP, with the synchronous development of the three primary north-south passageways. Trans-Hengduan routes might have been the most crucial artery connecting China and South and Southeast Asia during 3000–2200 BP, but more archeological records are needed to understand the detailed evolution of these transport networks.

Ordered mesoporous TiO2 framework confined CeSn catalyst exhibiting excellent high activity for selective catalytic reduction of NO with NH3 at low temperature

Synthesis of the cerium-based catalyst with excellent activity, selectivity, and toxicity resistance is one of the difficult problems for the selective reduction of NO by NH3 (NH3-SCR) at low temperature. Herein, we synthesize a novel and rational framework-confined ordered mesoporous CeSnOx/TiO2-E catalyst. Through a classical evaporation-induced self-assembly (EISA) strategy, the active components participate in the formation process of ordered mesoporous, which confines the catalytic active species into the interior of the overall structure. Via an array of microscopic characterizations and spectroscopic analysis, we have discovered that the presence of the ordered mesoporous structure makes the catalyst have a prominent confined effect on the framework. The high dispersion of nanoparticles in the system is realized here. Meanwhile, the cerium-based with Sn-doped catalyst system achieves the change of electronic structure and increases the charge exchange frequency, which enables the catalyst to acquire outstanding redox ability and abundant acidic sites. In addition, the ordered mesoporous structure of the catalyst guided the active components to produce a synergistic effect, and the uniform pore structure and metal doping enhanced the anti-poisoning ability. This strategy not only improves the low-temperature catalytic performance of the catalyst but also protects the nanoparticles from poisoning, which is beneficial to the long-time stability of the NH3-SCR reaction.

Total supply capability model for distribution network with electric trading market

The electricity trading market promotes the frequency and scale of power exchange in the distribution network, the uncertainty of trading volume, trading duration, and trading partners affect the total supply capability (TSC) of the distribution network (DN). The paper proposed a TSC model of DN with electric trading market. Firstly, the load clearing model of electricity trading is established. Then, the least square method is used to fit the growth curve functions of conventional load and power trading load. TSC model of DN is developed based on the growth functions of two loads. Finally, the TSC model is solved by the improved repetitive power flow algorithm (RPA). The simulation results of the improved IEEE 54-bus test system verify the feasibility and applicability of the proposed TSC model.

Problems and countermeasures associated with intercultural adaptation in international education according to the communication action theory model.

Due to the development of the Chinese economy, the consolidation of national power worldwide, and the increasing frequency of economic and cultural exchanges with foreign countries, the number of people from various countries who travel to China to engage in exchanges has increased significantly. Given the development of economic globalization, the acceleration of the process of educational internationalization represents a general trend in higher education development and a common requirement for universities. In addition to education, international students also experience cross-cultural adaptation, that is, behavioral adaptation or changes that occur in people in response to changes in their home country, whether in the form of external or internal cultural adaptation. For international students, the problem of cross-cultural adaptation not only hinders their learning progress but also affects their psychology and living conditions. This article explains the construction of Habermas’s theory of communication action. According to this theory, the purpose of communication is to coordinate the common actions of actors, and this coordination is achieved through mutual communication, which is mediated by language. The article also discusses the cross-cultural adaptation experienced by international students in Chinese universities and highlights the importance of developing educational services for international students in the context of international education. Studies have shown that female students exhibit slightly worse psychological adaptation than male students and female students have a slightly higher rate of depression rate than male students. An interpersonal study of 120 international students traveling to China found that most of these students (60%) were able to adapt in terms of their interpersonal relationships. To solve the problems associated with cross-cultural adaptation of international students in China, some countermeasures have been proposed, mainly including active participation in interpersonal communication, an enhanced understanding of the new culture, and the amplification of cultural identity.

Comprehensive Assessment of Indian Variations in the Druggable Kinome Landscape Highlights Distinct Insights at the Sequence, Structure and Pharmacogenomic Stratum.

India confines more than 17% of the world’s population and has a diverse genetic makeup with several clinically relevant rare mutations belonging to many sub-group which are undervalued in global sequencing datasets like the 1000 Genome data (1KG) containing limited samples for Indian ethnicity. Such databases are critical for the pharmaceutical and drug development industry where diversity plays a crucial role in identifying genetic disposition towards adverse drug reactions. A qualitative and comparative sequence and structural study utilizing variant information present in the recently published, largest curated Indian genome database (IndiGen) and the 1000 Genome data was performed for variants belonging to the kinase coding genes, the second most targeted group of drug targets. The sequence-level analysis identified similarities and differences among different populations based on the nsSNVs and amino acid exchange frequencies whereas a comparative structural analysis of IndiGen variants was performed with pathogenic variants reported in UniProtKB Humsavar data. The influence of these variations on structural features of the protein, such as structural stability, solvent accessibility, hydrophobicity, and the hydrogen-bond network was investigated. In-silico screening of the known drugs to these Indian variation-containing proteins reveals critical differences imparted in the strength of binding due to the variations present in the Indian population. In conclusion, this study constitutes a comprehensive investigation into the understanding of common variations present in the second largest population in the world and investigating its implications in the sequence, structural and pharmacogenomic landscape. The preliminary investigation reported in this paper, supporting the screening and detection of ADRs specific to the Indian population could aid in the development of techniques for pre-clinical and post-market screening of drug-related adverse events in the Indian population.

Spectral gap of replica exchange Langevin diffusion on mixture distributions

Langevin diffusion (LD) is one of the main workhorses for sampling problems. However, its convergence rate can be significantly reduced if the target distribution is a mixture of multiple densities, especially when each component density concentrates around a different mode. Replica exchange Langevin diffusion (ReLD) is a sampling method that can circumvent this issue. This approach can be further extended to multiple replica exchange Langevin diffusion (mReLD). While ReLD and mReLD have been used extensively in statistics, molecular dynamics, and other applications, there is limited existing analysis on its convergence rate and choices of the temperatures. This paper addresses these problems assuming the target distribution is a mixture of log-concave densities. We show ReLD can obtain constant or better convergence rates. We also show mReLD with K additional LDs can achieve the same results while the exchange frequency only needs to be (1/K)-th power of the one in ReLD.

An Automatic Pronunciation Error Detection and Correction Mechanism in English Teaching Based on an Improved Random Forest Model

Teachers in traditional English classes focus more on writing and grammar instruction, while oral language instruction is neglected. In exam-oriented education, most Chinese students can master English written test skills, but only a few students can communicate effectively in English daily. People are progressively realizing that language is a tool for communication and communication in recent years, as the frequency of international exchanges has increased and that language learning should focus on oral language education. However, there are numerous issues with teaching oral English. When students perform individual oral practice after class, for example, they are unable to determine whether their pronunciation is correct. As a result, a computer-assisted study into automatic pronunciation of spoken English has become a viable solution to these issues. However, the present spoken English pronunciation mistake correction model’s accuracy and stability have not yet reached an optimal level. Based on this background, this work provides an enhanced random forest model and uses it to detect and correct automatic pronunciation errors in English classes. The improved random forest (RF) algorithm is used to classify and detect whether the learner’s pronunciation is correct. Mel cepstral coefficient (MFCC) is used for feature extraction, and principal component analysis (PCA) is used for dimensionality reduction of feature data. The experimental structure demonstrates that by using a combination classification framework based on MFCC, PCA, and RF, the learner’s pronunciation difficulty may be resolved. This allows for different error categories to receive feedback corrections.

Analysis of the Effectiveness of Green Waste Composting under Hyperbaric Conditions

Increasing global population growth has a significant impact on waste production. The European Union (EU) focuses on waste recycling, biological treatment, and reuse. In the case of biodegradable waste, a significant problem is the long process of material decomposition so that the product meets the requirements of national regulations and EU directives. The search for a way to accelerate this process is still ongoing. This study presents the composting process of green waste under hyperbaric conditions. Eight experiments, four with air exchange frequency tAE = 4 h and four experiments with tAE = 8 h were established. The experiments were conducted in four variants: 0 (atmospheric pressure) and overpressures 50, 100, and 200 kPa. They were carried out on the same input material characterized by the initial moisture content of 60% and a mass of 2000 g. During the composting of green waste, all parameters of the obtained product (moisture content, pH, loss on ignition (LOI), C:N ratio, nutrient content (P, K), and the respiratory activity of microorganisms (AT4)) were also evaluated. The most significant weight loss of the composted material was observed in the variant of an overpressure of 200 kPa (tAE = 4 h). The compost weight in relation to the original material decreased by 23.7%. The highest organic matter removal efficiency was obtained for the overpressure variants of 50 and 100 kPa (tAE = 4 h).

The non-ideal finite Larmor radius effect in the solar atmosphere

ABSTRACT The dynamics of the partially ionized solar atmosphere is controlled by the frequent collisions and charge exchange between the predominant neutral hydrogen atoms and charged ions. At signal frequencies below or of the order of either of the collision or charge exchange frequencies, the magnetic stress is felt by both the charged and neutral particles simultaneously. The resulting neutral-mass loading of the ions leads to the rescaling of the effective ion-cyclotron frequency (it becomes the Hall frequency), and the resultant effective Larmor radius becomes of the order of few kms. Thus, the finite Larmor radius effect that manifests as the ion and neutral pressure stress tensors operates over macroscopic scales. Whereas parallel and perpendicular (with respect to the magnetic field) viscous momentum transport competes with the Ohm and Hall diffusion of the magnetic field in the photosphere–chromosphere, the gyroviscous effect becomes important only in the transition region between the chromosphere and corona, where it competes with the ambipolar diffusion. The wave propagation in the gyroviscous effect-dominated medium depends on the plasma β (a ratio of the thermal and magnetic energies). The abundance of free energy makes gyro waves unstable with the onset condition exactly opposite of the Hall instability. However, the maximum growth rate is identical to the Hall instability. For a flow gradient of ${\sim} 0.1 \, \mbox{s}^{-1}$, the instability growth time is 1 min. Thus, the transition region may become subject to this fast-growing gyroviscous instability.

English Pronunciation Calibration Model Based on Multimodal Acoustic Sensor

In recent years, with the increasing frequency of international exchanges, people have gradually realized that language is a tool of communication and communication, and language learning should attach importance to oral teaching. However, in traditional classrooms, one of the problems faced by oral teaching is the mismatch of the teacher-student ratio: a teacher has to deal with dozens of students, one-on-one oral teaching and pronunciation guidance is impossible, and it is also affected by the teachers and the environment constraints. Therefore, the research on how to efficiently automate pronunciation training is becoming more and more popular. Many phonemes in English have different facial visual features, especially vowels. Almost all of them can be distinguished by the roundness and tightness of the lips in appearance. In order to give full play to the role of lip features in oral pronunciation error detection, this paper proposes a multimodal feature fusion model based on lip angle features. The model interpolates the lip features constructed based on the opening and closing angles and combines audio and video in time series. Feature alignment and fusion and feature learning and classification are realized through the two-way LSTM SOFTMAX layer, and finally, end-to-end pronunciation error detection is realized through CTC. It is verified on the GRID audio and video corpus after phoneme conversion and the self-built multimodal test set. The experimental results show that the model has a higher false pronunciation recognition rate than the traditional single-modal acoustic error detection model. The increase in error detection rate is more obvious. Verification by the audio and video corpus with white noise was added, and the proposed model has better noise immunity than the traditional acoustic model.

Allied male dolphins use vocal exchanges to “bond at a distance”

Vocal interactions are intrinsic features of social groups and can play a pivotal role in social bonding.1,2 Dunbar's social bonding hypothesis posits that vocal exchanges evolved to "groom at a distance" when social groups became too large or complex for individuals to devote time to physical bonding activities.1,3 Tests of this hypothesis in non-human primates, however, suggest that vocal exchanges occur between more strongly bonded individuals that engage in higher grooming rates4-7 and thus do not provide evidence for replacement of physical bonding. Here, we combine data on social bond strength, whistle exchange frequency, and affiliative contact behavior rates to test this hypothesis in wild male Indo-Pacific bottlenose dolphins, who form multi-level alliances that cooperate over access to females.8-10 We show that, although whistle exchanges are more likely to occur within the core alliance, they occur more frequently between those males that share weaker social bonds, i.e., between core allies that spend less time together, while the opposite occurs for affiliative physical contact behavior. This suggests that vocal exchanges function as a low-cost mechanism for male dolphins that spend less time in close proximity and engage in fewer affiliative contact behaviors to reinforce and maintain their valuable alliance relationships. Our findings provide new evidence outside of the primate lineage that vocal exchanges serve a bonding function and reveal that, as the social bonding hypothesis originally suggested, vocal exchanges can function as a replacement of physical bonding activities for individuals to maintain their important social relationships.

An Event-Triggered Approach for Gradient Tracking in Consensus-Based Distributed Optimization

This paper is concerned with a communication-efficient algorithm update scheme for solving distributed convex optimization problems by introducing a distributed event-triggered approach. Compared with real-time consensus-based distributed optimization algorithms in the literature, this paper focuses on extending the real-time gradient tracking scheme and proposes a novel distributed event-triggering condition to reduce the frequency of information exchange between agents in a network. The proposed event-triggered approach for consensus-based distributed optimization algorithms not only avoids the real-time consecutive communication and the coordinated computation between agents but reduces the computation load of algorithm execution. Furthermore, the proposed event-triggering condition depends on only local states from neighbors at only their event times and does not require a global and homogeneous sampling period. In addition, this paper analytically shows that the proposed consensus-based distributed optimization algorithm based on an event-triggered approach can also converge to the exact optimal solution with a linear convergence rate even if the real-time consecutive communication between agents is replaced with sporadic communication.

Genotoxicity of Glyphosate on Cultured Human Lymphocytes.

Glyphosate-based herbicides are the most used herbicides in the world. Despite being widely used, a dispute exists whether glyphosate-based herbicides have a negative effect on human health, particularly genotoxic effects. Therefore, the aim of this study was to investigate glyphosate genotoxicity on cultured human lymphocytes. Cultured human lymphocytes were treated with different concentrations of glyphosate (20, 40, and 200µmol/L). Four toxicity measures were examined: frequency of chromosomal aberrations (CAs), frequency of sister-chromatid exchange (SCE), production of 8-OHdG, and cell kinetics analysis. The results show that glyphosate induced significant (P < 0.05) increases in the levels of SCE at the highest used concentration (200μmol/L). However, no significant elevation in SCE levels was observed at the lower examined concentrations (20 and 40μmol/L). No significant changes in CA were detected at all examined concentrations (P = 0.86). Also, glyphosate did not induce changes to the normal level of 8-OHdG at all examined concentrations (P = 0.98). Last, no significant changes in either mitotic index or proliferative index were observed at any examined concentrations (P > 0.05). The results collectively indicate a lack of genotoxicity and cytotoxicity of glyphosate in cultured human lymphocytes when dealing with environmentally relevant concentrations (20 and 40μmol/L). However, being exposed to higher concentrations (200μmol/L) led to slightly higher level of SCE. Therefore, we recommend cautionary measures when dealing with glyphosate-based herbicides for individuals, such as farmers, who may be extensively exposed to high concentrations of these herbicides.

Fruitful exchanges: social networks and food resources amidst change

BackgroundThe Amazon region of Brazil is known both for its significant biological and cultural diversity. It is also a region, like many parts of the country, marked by food insecurity, even amongst its rural agricultural populations. In a novel approach, this paper addresses the networks of exchanges of local food and their relationship to the agrobiodiversity of traditional riverine peoples’ (ribeirinho) households in the Central Amazon. Methodologically, it involves mapping the social networks and affinities between households, inventories of known species, and, finally, statistical tests of the relationships between network and subsequent agrobiodiversity.ResultsThe diversity per area of each land type where food cultivation or management takes place shows how home gardens, fields and orchards are areas of higher diversity and intense cultivation compared to fallow areas. Our findings, however, indicate that a household’s income does appear to be strongly associated with the total agrobiodiversity across cultivation areas. In addition, a household’s agrobiodiversity is significantly associated with the frequency and intensity of food exchanges between households.ConclusionsAgrobiodiversity cannot be considered separate from the breadth of activities focused on sustenance and yields from the cash economy, which riverine people engage in daily. It seems to be connected to quotidian social interactions and exchanges in both predictable and occasionally subtler ways. Those brokers who serve as prominent actors in rural communities may not always be the most productive or in possession of the largest landholdings, although in some cases they are. Their proclivity for cultivating and harvesting a wide diversity of produce may be equally important if not more so.

Regularized lattice Boltzmann method parallel model on heterogeneous platforms

AbstractAs an improved method of lattice Boltzmann method (LBM), regularized lattice Boltzmann method (RLBM) has been applied to simulate fluid flow. Nevertheless, the performance of RLBM needs to be considered when simulating actual problems. The rise of multicore platforms, especially the popularity of graphics processor units (GPUs), has provided possible implementation solutions for parallel computing. In this article, an RLBM parallel model on the CPU/GPU heterogeneous platforms is proposed. To solve the problem of possible GPU memory shortage, the CPU controls the startup of the kernel function in the RLBM algorithm and participates in the calculation. Due to the characteristics of the algorithm, the entire flow field is divided into CPU computing areas and GPU computing areas according to the given flow field division rules. OpenMP and CUDA are, respectively, applied to CPU and GPU for parallel computing. The startup of the kernel function takes a short time, and the CPU and GPU can be approximately regarded as performing calculations simultaneously. Since the data exchange between the CPU and GPU has a significant impact on performance, a buffer is set at the boundary of the CPU and GPU to reduce the frequency of data exchange. The buffer size determines the number of program iterations before exchanging data. The performance of the algorithm is measured by MFLUPS, and the algorithm is applied to the 3D lid‐driven cavity flow. The obtained results show that the MFLUPS of the algorithm is 25 times that of CPU MFLUPS, and it adds an increment equivalent to CPU MFLUPS compared with GPU MFLUPS. And the algorithm is extended to a multi‐GPU version, which is also applied to the 3D lid‐driven cavity flow. The results obtained show that the MFLUPS of the multi‐GPU version is 1.8 times that of the single GPU.

The association between social ties and changes in depressive symptoms among veterans enrolled in a collaborative depression care management program.

A greater understanding of factors that are associated with successful outcomes among patients receiving collaborative depression care services is needed. This study sought to examine the unique associations between 3 indices of social ties and changes in depressive symptoms among veterans receiving collaborative depression care management. Data on sociodemographics, behavioral health indices, perceived general health, perceived social support, frequency of negative social exchanges, and degree of social contact were extracted from the electronic health records of 868 veterans meeting criteria for at least moderate depressive symptom severity and enrolled in a Primary Care-Mental Health Integration (PCMHI) program. Veterans were on average 51.3 (SD = 15.9) years old and primarily male. Higher depressive symptoms at baseline were significantly correlated with less perceived social support, less frequent contact with family and friends, and greater frequency of negative social exchanges. Adjusted regression analyses revealed that only social contact was significantly related to changes in depressive symptoms over the course of care management, once controlling for covariates. The results highlight the value of taking multiple indices of social ties into account when providing depression care management services. Routinely assessing patients' level of social contact can potentially help tailor and inform intervention efforts aimed at reducing depressive symptoms. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

He-enhanced heterogeneity of radiation-induced segregation in FeNiCoCr high-entropy alloy

• Atom probe tomography reveals radiation-induced segregation around He bubbles • Electron energy-loss spectroscopy measures He density and pressure inside bubbles • The inverse Kirkendall effect dominates RIS around over-pressurized He bubbles • He atoms retard Co diffusion via the vacancy mechanism and enhance Co segregation • Local chemical order of medium-/high-entropy alloys can be tailored via He bubbles Radiation-induced segregation (RIS) is a typical non-equilibrium process that can dramatically alter the behavior of defect sinks and material properties under irradiation. However, RIS mechanisms have been rarely studied around small He bubbles owing to the technical challenges involved in direct measurements of local chemistry. Here, using state-of-the-art atom probe tomography, we report the RIS behavior near He bubbles in the FeNiCoCr high-entropy alloy that indicates Co segregates most strongly, followed by weaker Ni segregation, whereas Fe and Cr are depleted almost to the same degree. Exceptionally, the magnitude of Co segregation around He bubbles is higher than previously measured values at voids and dislocation loops. Electron energy-loss spectroscopy was used to measure the He density and pressure inside individual bubbles. We demonstrate that He bubbles are over-pressurized at the irradiation temperature that could result in the vacancy bias and the subsequent vacancy-dominated RIS mechanism. First-principles calculations further reveal that there are repulsive interactions between He and Co atoms that may reduce the frequency of Co-vacancy exchange. As a result, He atoms likely retard Co diffusion via the vacancy mechanism and enhance the heterogeneity of RIS in Co-containing multicomponent alloys. These insights could provide the basis for understanding He effects in nuclear materials and open an avenue for tailoring the local chemical order of medium-and high-entropy alloys.