Direct numerical simulations are carried out to investigate the underlying mechanism of the low-frequency unsteadiness of a transitional shock reflection with separation at $M=1.5$. To clarify the nonlinear mechanisms, the incoming laminar boundary layer is forced with two different arrangements of oblique unstable modes. Each wave arrangement is given by a combination of two unstable waves such that their difference in frequency falls in a low-frequency range corresponding to a Strouhal number (based on the length of interaction) of 0.04. This deterministic forcing allows the introduction of nonlinearities, and high-order statistical tools are used to identify the properties of quadratic couplings. It is found that the low-frequency unsteadiness and the transition to turbulence are decoupled problems. On the one hand, the unstable modes of the boundary layer interact nonlinearly such that energy cascades to higher frequencies, initiating the turbulent cascade process, and to lower frequencies. On the other hand, the low-frequency quadratic coupling of the oblique modes is found to be responsible for low-frequency unsteadiness affecting the separation point. The direction of the quadratic interactions is extracted and it is shown that, in the presence of low-frequency unsteadiness, these interactions enter the separated zone just before reattachment and travel both downstream and upstream, extending beyond the separation point, hence feeding the low-frequency bubble response. In addition to the two main arrangements of oblique modes, two other combinations are analysed, including multiple oblique waves and streaks. Interestingly, their inclusion did not alter the low-frequency unsteadiness phenomenon. Furthermore, the effect of the forcing difference frequency is examined and it is shown that the breathing phenomenon is sensitive to the range of frequencies present in the system due to a low-pass filter effect.

Word age of acquisition (AoA) influences many aspects of language processing, including reading. However, reading studies of word AoA effects have almost exclusively focused on monolingual young adults, leaving their influence in other age and language groups little understood. Here, we investigated how age (childhood, young adulthood) and language background (monolingual, bilingual) influence word AoA effects during first-language (L1) and second-language (L2) reading. Using eye-tracking, we observed larger L1 word AoA effects in children versus adults (across both language backgrounds). Moreover, we observed larger L2 versus L1 word AoA effects in bilinguals (across both ages), with some evidence of heightened effects in bilingual adults (for late-stage reading only). Taken together, our findings suggest that word AoA exerts a stronger influence on reading during conditions of reduced lexical entrenchment, offering critical insights into how both developing and bilingual readers acquire and maintain word representations across their known languages.

Ionizing radiation is known to have a destructive effect on biology by causing damage to DNA, cells and the production of reactive oxygen species, among other things. While direct exposure to high-radiation dose is indeed not favorable for biological activity, ionizing radiation can and, in some cases, is known to produce a number of biologically useful products. One such mechanism is the production of biologically useful products via charged particle-induced radiolysis. Energetic charged particles interact with the surfaces of planetary objects such as Mars, Europa and Enceladus without much shielding from their rarefied atmospheres. Depending on the energy of said particles, they can penetrate several meters deep below the surface and initiate a number of chemical reactions along the way. Some of the byproducts are impossible to produce with lower-energy radiation (such as sunlight), opening up new avenues for life to utilize them. The main objective of the manuscript is to explore the concept of a Radiolytic Habitable Zone (RHZ), where the chemistry of galactic cosmic ray-induced radiolysis can be potentially utilized for metabolic activity. We first calculate the energy deposition and the electron production rate using the GEANT4 numerical model, then estimate the current production and possible chemical pathways which could be useful for supporting biological activity on Mars, Europa and Enceladus. The concept of RHZ provides a novel framework for understanding the potential for life in high-radiation environments. By combining energy deposition calculations with the energy requirements of microbial cells, we have defined the RHZ for Mars, Europa and Enceladus. These zones represent the regions where radiolysis-driven energy production is sufficient to sustain microbial metabolism. We find that bacterial cell density is highest in Enceladus, followed by Mars and Europa. We discuss the implications of these mechanisms for the habitability of such objects in the solar system and beyond.

In small-plot experiments, weed scientists have traditionally estimated herbicide efficacy through visual assessments or manual counts with wooden frames—methods that are time-consuming, labor-intensive, and error-prone. This study introduces a novel mobile application (app) powered by convolutional neural networks (CNNs) to automate the evaluation of weed coverage in turfgrass. The mobile app automatically segments input images into 10 by 10 grid cells. A comparative analysis of EfficientNet, MobileNetV3, MobileOne, ResNet, ResNeXt, ShuffleNetV1, and ShuffleNetV2 was conducted to identify weed-infested grid cells and calculate weed coverage in bahiagrass (Paspalum notatum Flueggé), dormant bermudagrass [Cynodon dactylon (L.) Pers.], and perennial ryegrass (Lolium perenne L.). Results showed that EfficientNet and MobileOne outperformed other models in detecting weeds growing in bahiagrass, achieving an F1 score of 0.988. For dormant bermudagrass, ResNet performed best, with an F1 score of 0.996. Additionally, app-based coverage estimates (11%) were highly consistent with manual assessments (11%), showing no significant difference (P = 0.3560). Similarly, ResNeXt achieved the highest F1 score of 0.996 for detecting weeds growing in perennial ryegrass, with app-based and manual coverage estimates also closely aligned at 10% (P = 0.1340). High F1 scores across all turfgrass types demonstrate the models’ ability to accurately replicate manual assessments, which is essential for herbicide efficacy trials requiring precise weed coverage data. Moreover, the time for weed assessment was compared, revealing that manual counting with 10 by 10 wooden frames took an average of 39.25, 37.25, and 42.25 s per instance for bahiagrass, dormant bermudagrass, and perennial ryegrass, respectively, whereas the app-based approach reduced the assessment times to 8.23, 7.75, and 14.96 s, respectively. These results highlight the potential of deep learning–based mobile tools for fast, accurate, scalable weed coverage assessments, enabling efficient herbicide trials and offering labor and cost savings for researchers and turfgrass managers.

We report the detection of a potential quasi-periodic signal with a period of $\sim$2 yr in the blazar ON 246, based on Fermi-LAT ($\gamma$-rays) and ASAS-SN (optical) observations spanning 11.5 yr (MJD 55932–60081). We applied various techniques to investigate periodic signatures in the light curves, including the Lomb-Scargle periodogram (LSP), weighted wavelet Z-transform (WWZ), and REDFIT. The significance of the signals detected in LSP and WWZ was assessed using two independent approaches: Monte Carlo simulations and red noise modelling. Our analysis revealed a dominant peak in the $\gamma$-ray and optical light curves, with a significance level exceeding 3$\sigma$ in both LSP and WWZ, consistently persisting throughout the observation period. Additionally, the REDFIT analysis confirmed the presence of a quasi-periodic signal at $\sim$0.00134 day$^{-1}$ with a 99$\%$ confidence threshold. To explain the observed quasi-periodic variations in $\gamma$-ray and optical emissions, we explored various potential physical mechanisms. Our analysis suggests that the detected periodicity could originate from a supermassive binary black hole (SMBBH) system or the jet-induced orbital motion within such a system. Based on variability characteristics, we estimated the black hole mass of ON 246. The study suggests that the mass lies within the range of approximately $(0.142 - 8.22) \times 10^9$ M$_{\odot}$.

The prominence and significance of research on specific learning differences (SpLDs) in language learning, teaching, assessment, and teacher education have substantially increased in the past ten years, which justifies the need to review the findings of studies conducted in recent years. The growth of the field also requires that the scope of the review is extended to research in the area of L2 assessment and teacher education. In our paper, we first offer a short discussion of different views of disability and inclusion and a succinct summary of the definitions of SpLDs. We then summarize recent research developments in five main areas: (1) the impact of SpLDs on L2 learning and achievement, (2) the identification of SpLDs in multilingual contexts, (3) teaching techniques and programmes in supporting language learners with SpLDs, (4) assessing the second language competence of test-takers with SpLDs, and (5) raising language teachers’ awareness and knowledge of SpLDs.

In our conclusion, we highlight the implications of recent scholarship in this field for language teaching and testing, teacher education, and suggest further research directions.

The 1960s in Czechoslovakia witnessed a remarkable political movement to foster what was then called “socialism with a human face” by merging the egalitarian-distributive vision of socialism with quasi-Western democratic values. This article investigates the social and emotional origins of Czechoslovak reformism and argues that the movement was rooted in the intersection between social class discontent and the collective emotional pain of a revolutionary intelligentsia that I call the “red-collars.” In doing this, the article explores how the post-revolutionary class structure and shared “melancholic” feelings of the red-collars (a mix of discontent with their material/social circumstances and regret for their part in Stalinist revolutionary excesses) shaped their ideological transformation from Stalinism to democratic socialism between 1948 and 1968. Throughout the 1960s, by declaring emotional pain over their past Stalinism, the red-collars voiced their desire to reform the system and reclaim what they considered the “humanistic core of socialism.”

This article critically examines the claim that the United Nations Security Council (UNSC) has acquired “legislative powers”, as suggested by the practices over the last two decades. This purported “legislative” role derives from Resolutions 1373, 1540, and 1422. However, an expansive interpretation of Chapter VII powers or viewing the UNSC as a legislative body within a “World Government” does not hold. Additionally, shifts in the international political landscape have made the expansion of UNSC’s legislative powers impossible, and the UNSC has largely refrained from adopting legislative resolutions in the past decade as they have learned the lessons from Resolution 1540. Finally, this article proposes a solution that although these resolutions do not qualify as a direct source of law under Article 38 of the Statute of the International Court of Justice (ICJ), their binding nature remains as acts détournement de pouvoir and shall not be regarded as ultra vires.

Since the 1980s, state capacity has been a major explanation for countries leaving the middle-income trap. However, this literature is unable to explain the failed experiences of countries with relatively high state capacity. This was the case of Chile after the unsuccessful enaction of a series of policies in the mid-2010s to upgrade the country’s position in the lithium value chain. To understand this failure, we combine the literature on developmental states and the literature on business power. We use the concept of institutional business power to understand how business actions erode state capacities leading to countries’ persistent inability to leave the middle-income trap. In the case of Chile, despite the relatively high levels of state capacity, previous processes of deregulation and privatization in the country configured a situation favorable to business’ monopolization of information and technical knowledge about lithium production and innovation processes that directly affected the capacity of the state to regulate the sector, let alone implement policies designed to upgrade the industry. The article highlights the need to investigate further the role of not just the state, but of the private sector in either facilitating or blocking value chain upgrading in countries caught in the middle-income trap.

This study, focused on the Czech Republic, examines the influence of ethnic nationalism on the public willingness to accept war refugees from countries with different cultural and religious backgrounds. We present evidence relating to forced migration from Ukraine (predominantly Christian) and from countries with predominantly Muslim populations. The theoretical-conceptual framework for our study encompasses the concepts of ethnicity and historical institutionalism, and the theory of social identity. Our theoretical analysis is strengthened by evidence from structured and semi-structured interviews. We find that ethnic nationalism does contribute in part to public rejection of migrants with different ethnic or religious backgrounds in the Czech Republic, as one of several factors that encourage a perceived ‘us’ versus ‘them’ dichotomy among certain sectors of the Czech population.

The growing reliance of militaries on artificial intelligence (AI) and machine learning (ML) technologies means that private software companies are assuming an increasingly central role in the conception and development of the tools of contemporary warfare. While most of the existing debate on algorithmic warfare has focused on autonomous weapons systems, the rise of AI-enabled software capabilities has largely been neglected. In this article, we examine how developers of AI- and ML-based military decision-support systems visually promote their software products. Building on insights from Critical Security Studies and Science and Technology Studies, we develop the argument that ‘virtual military demonstrations’, as we label this practice, facilitate technology companies’ claim of epistemic authority on the future of war. This allows commercial actors to represent algorithmic warfare as a strategic and moral imperative for the survival of Western democracies. Through detailed studies of virtual demonstrations by Palantir and Anduril, two US-based defence tech companies, we illustrate how algorithmic warfare is visually and discursively represented as a clean, controllable, and precise business, disconnected from the lived experiences of innocent victims and their environments. We conclude that the obfuscation of the realities of warfare in such a way has important implications which warrant further scrutiny.

Mass transport induced by group-forced subharmonic waves (infragravity waves) is investigated in the present study. A theoretical solution for subharmonic waves’ kinematic contributions to fourth-order mass transport and drift velocity has been proposed for any depth and bandwidth for the first time. This model is validated using particle-tracking simulations driven by the flow field generated by the SWASH. The subharmonic-induced mass transport solution is a weighted sum of the subharmonic velocity variance spectrum and velocity skewness bispectrum due to the triad-difference interaction among two primary and one subharmonic components. For narrow-banded waves with long wave group relative to depth, the weightings become independent of spectral components, and the solution is recovered in the time domain. Two mechanisms contributing to mass transport were identified: a forward drift resulting from self-interaction similar to Stokes drift, and a depth-decaying backward drift induced by negative subharmonic velocity skewness due to the anti-phase coupling between subharmonics and wave groups. For narrow-banded waves the forward transport surpasses the backward transport for kh< 0.72, where k is the short wave wavenumber and h is the water depth. For other waves, the critical kh for this phenomenon decreases with increasing wave period and bed slope and decreasing bandwidth. At greater depths or steeper bed slopes, near-surface backward transport predominates over forward transport; at shallower depths or gentler slopes, forward transport is dominant throughout the water column. Although smaller than Stokes transport by short waves, the subharmonic wave-induced mass transport can affect the long-term trajectory of a floating and suspended particle. This study provides the first evidence and insight for the influences of group-forced subharmonics on vertically varying mass transport from the ocean surface to seabed in coastal environments.

The superfamily Diplostomoidea Poirier, 1886 is a large, globally distributed group of digeneans characterized by the presence of a unique holdfast organ and parasitic in most major groups of vertebrates (birds, mammals, reptiles, fishes) as definitive hosts. A number of diplostomoideans are associated with diseases in their intermediate and, more rarely, definitive hosts. Prior to this work and upon the recent synonymization of the Brauninidae Wolf, 1903, the Diplostomoidea included 5 families: Bolbocephalodidae Strand, 1935; Cyathocotylidae Mühling, 1896; Diplostomidae Poirier, 1886; Proterodiplostomidae Dubois, 1936; and Strigeidae Railliet, 1919. The separation of these families was based primarily on the structure and shape of prosoma and holdfast organ as well as the presence/absence of cirrus sac and paraprostate. More rarely, distinguishing among families was based on life cycles and types of larval stages, excretory system or even host specificity. However, due to the inconsistent nature of most of morphological and biological characters across the Diplostomoidea and nearly universal lack of agreement on their relative value, the systematic history of the group has been extremely tumultuous, and none of many classification systems proposed over the last 140 years has become broadly accepted or supported by phylogenetic analyses. Extensive molecular phylogenetic studies of the Diplostomoidea in the last 15 years helped to partly improve the classification system and resolve multiple taxonomic questions. Notably, practically all molecular phylogenies have clearly demonstrated non-monophyly of the two largest families, the Diplostomidae and the Strigeidae and indicated it as systematic problem. We provide a brief overview of the history and current state of knowledge of diplostomoidean systematics and re-evaluate the classification system of the Diplostomoidea based on morphological and molecular evidence. We propose changes in the classification system that reconciles the traditional morphological and life cycle data with molecular phylogenies. The major element of the proposed classification system is the synonymization of the families Proterodiplostomidae and Strigeidae with the Diplostomidae as the only feasible way to resolve the problem of consistent non-monophyly of the latter two families and provide stability to the classification system.