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An important category of microscale fluid–structure interactions concerns how flexible fibres deform and interact with flows. Many experimental and numerical studies have focused on the shape dynamics of fibres in linear shear flows. Here, instead, we consider a fully three-dimensional background flow with non-constant vorticity and study the shape evolution of fibres in a zero-Reynolds-number analogue of a Burgers vortex. This flow is created by the superposition of regularised singularities of the Stokes equations. Using a Kirchhoff rod model with regularised Stokeslet segments that track both curvature and torsion evolution along the fibre, we observe novel three-dimensional deformations. The shape dynamics depends on two non-dimensional parameters: an elastoviscous number and the ratio of vortex core diameter to fibre length. We focus on the special case of fibre excursions when the fibre is placed in the horizontal plane of symmetry, centred at the vortex core. We reveal robust orbits where fibres spin about the z axis as they deform, but ultimately straighten out and reach a vertical equilibrium state. Our model demonstrates that the fibre flexibility influences the time it takes to complete this orbit, with flexible fibres reaching equilibrium sooner than their stiffer counterparts. In addition, we demonstrate that fibres placed asymmetrically within this fully three-dimensional background flow exhibit a wide array of shape evolutions, including helical buckling.
This longitudinal study monitored Theory-of-Mind development in monolingually raised but bilingually educated Spanish children (age 5–6) with varied L2-English curricula (13%–83%) to assess whether higher L2-exposure resulted in advantages on seven ToM concepts (emotion, desires, belief, reference, moral-reasoning, lies, sarcasm). Attention (selective, switching, inhibition) and a full suite of individual-difference effects were also monitored. GLMMs linked greater L2-exposure to higher ToM accuracy, and although all three attention measures contributed to ToM scores, the effect of selective attention was the strongest. L1-vocabulary and NVR routinely predicted ToM scores, and girls surpassed boys on sarcasm. We conclude that bilingualism spurs ToM development quickly and is not linked to L2-vocabulary at this stage. In addition, the fact that L2-exposure and individual differences impacted cognitive, affective, and conative ToM differentially supports an approach that analyses these components separately.
Old Saxon shows sporadic vowel insertions, a phenomenon whereby a vowel is inserted into heterorganic post-nucleic liquid–consonant sequences. The process is highly variable, and differences occur within and across manuscripts and lemmas. Moreover, the phenomenon is under-researched and has hitherto been analyzed as a mechanism to dissolve challenging liquid–consonant clusters by causing resyllabification of the liquid. This article provides a corpus-based analysis of the Old Saxon vowel insertions to establish the most detailed investigation of the process thus far. The findings suggest that the Old Saxon phenomenon is an instance of vowel intrusion rather than phonological vowel epenthesis.*
When activists act as unelected representatives by voicing political demands on behalf of various constituencies, does this affect citizens’ satisfaction with democracy? We theorize that this may be the case if and when such individuals constitute an effective channel of representation, meaning that (1) activists substantively represent individuals and (2) they are included in politics. Furthermore, we theorize that marginalized individuals become more satisfied with the way democracy works when they witness activists with whom they agree. We test this through a preregistered vignette experiment in Sweden, Germany, Italy, and Romania (N = 8196). Our findings are mixed. Unelected representatives can sway citizens’ satisfaction with democracy in some instances. Specifically, the electoral winner–loser gap can be narrowed through substantive representation from unelected representatives. This presents an invitation for further research on the role activists play in shaping the legitimacy of liberal representative democracies.
In a posthumous publication in 1954, seven years after his death, Reuben Anywar became the second Acholi to publish a book. Acoli ki Ker Megi was released one year after Lacito Okech’s Tekwaro ki Ker Lobo Acholi. Unlike Okech, who received little education, Anywar was among the first northern Ugandan graduates of Makerere College. He became one of the first Black teachers at the prestigious Gulu High School and was the founder and original editor of Acholi Magazine. By the mid-1940s, Anywar was arguably the most towering intellectual in northern Uganda. Yet, existing works overlook his significance in knowledge production. This article seeks to rectify this oversight.
Over the past decade, interest, stakeholder engagement, and investment in the cultivation of intermediate wheatgrass (IWG) as a perennial grain crop have increased across the Upper Midwest, USA. IWG has been promoted as a multipurpose crop that provides both agricultural products and ecosystem services. Our objective in this study was to describe the current IWG landscape in the Midwest from the perspective of farmers growing the crop, including their objectives, management practices, and the challenges they face. We also examined the concept of multifunctionality within the context of integrating a minor crop into existing farming systems. Semi-structured interviews were conducted with IWG growers in the Upper Midwest. Results show that, beyond direct agronomic benefits, these growers were motivated by a broader vision of agriculture. Due to its distinctive traits, IWG served as a tool to accomplish various non-commercial dimensions of farming such as environmental conservation, education, and community building, and for fulfilling farmers’ roles as producers, environmental stewards, and citizens. At the same time, the regional socio-technical context imposed strong constraints on IWG production, particularly in terms of profitability and processing. Cropping practices reflected both the influence of uniform technical recommendations and the need for adaptation to individual farm systems and farmer expertise. Overall, this study provides insight into farmers’ perspectives, motivations, and concerns regarding IWG cultivation in the United States.
Digital interventions for promoting relaxation are increasingly popular, yet few combine multiple sensory modalities. This study evaluated the effectiveness of a fully digital relaxation program combining hypnotherapy with aromatherapy and explored whether the scent can induce a conditioned relaxation effect.
Methods
In this four-arm randomized controlled trial (N = 504), participants were assigned to one of four groups for a 4-week intervention: (a) combined (hypnotherapy + aromatherapy), (b) hypnotherapy-only, (c) aromatherapy-only, or (d) control (minimal intervention pause). Sessions were self-guided and delivered online every 2 days. The primary outcome was subjective calmness, assessed via the calmness–restlessness subscale of the Multidimensional Mood Questionnaire. Secondary outcomes included perceived stress (PSS-10) and well-being (WHO-5). A fifth week with aromatherapy-only exposure was conducted in the combined and aromatherapy-only groups to test for conditioning.
Results
At post-intervention, both hypnotherapy-involved groups reported significant greater calmness than controls. The combined group showed a mean difference of β = 2.08 (95% CI: 0.50–3.65, p = 0.010, d = 0.38), while the hypnotherapy-only group showed β = 1.80 (95% CI: 0.24–3.37, p = 0.024, d = 0.33). Both effects were consistent across intention-to-treat and per-protocol analyses. Within-group improvements in calmness were also observed across all groups. No significant differences emerged from the conditioning test in week 5.
Conclusions
Digital hypnotherapy improved relaxation, with modest added benefit from aromatherapy. The results support the use of multisensory digital tools to enhance subjective calmness. However, no evidence for conditioned effects of the scent was observed under the current conditions.
Richtmyer–Meshkov instability (RMI) at a single-mode interface separating an inert gas (N$_2$) and a reactive gas mixture (H$_2$/O$_2$/Xe) under reshock conditions is numerically investigated using a newly developed compressible reactive Navier–Stokes solver. The solver employs the Kéromnès mechanism (10 species, 21 reactions) for combustion modelling and a dual-flux algorithm to suppress numerical oscillations at material interfaces, demonstrating high accuracy across a wide range of benchmark tests. By systematically varying incident shock Mach numbers, we identify four distinct evolution regimes: an inert regime (${\textit{Ma}} \lt 1.80$), characterised by negligible combustion effects on interface evolution; a deflagration regime ($1.80 \lt Ma \lt 1.86$), marked by strong coupling between interface dynamics and combustion through sustained interactions; a detonation regime ($1.86 \lt Ma \lt 2.50$), where rapid transition to detonation leads to moderate coupling; and an immediate detonation regime (${\textit{Ma}} \gt 2.50$), where detonation occurs directly after incident shock impact, modifying interface evolution from the outset through intense heat release and pressure waves. Mixing width and mixing level are most significantly enhanced in the deflagration regime due to prolonged combustion-flow interactions, while cases with higher Mach numbers show reduced mixing due to rapid combustion completion. Heat release and enstrophy also display clear regime-dependent evolution behaviour: maximum heat release occurs in the detonation regime, while peak enstrophy is observed in the deflagration regime. A clear correlation is observed between the Damköhler number ($Da$), which represents the ratio of hydrodynamic to chemical time scales, and the flow regimes: for ${\textit{Ma}} \lt 1.80$, $Da \lt 1$ indicates negligible coupling; at ${\textit{Ma}} = 1.83$, $Da \approx 1$ reflects sustained coupling; and for ${\textit{Ma}} \gt 2.00$, $Da \gt 1$ denotes strong early coupling. This correlation provides a theoretical basis for interpreting the distinct regimes and guiding the modulation of reactive RMI.
Lizards represent a diverse group, adapted to a wide variety of environments, and interact with a wide range of parasites. The composition of a parasitic community can be influenced by several factors, including the host, the environment, and the parasite itself. This study evaluated the composition of the helminth community in three species of lizards of the genera Ameiva, Ameivula, and Tropidurus, from a Carrasco habitat in Chapada do Araripe, Brazil. Carrasco is a little-explored environment in which the diversity of hosts and parasites is still poorly understood. The composition of the helminth community associated with lizard species was evaluated by comparing richness, evenness, dominance, and diversity among component communities, including host sex and size as influencing factors, using different statistical comparison tools. The community consisted of 12 taxa from eight genera of parasitic helminths, seven of which were Nematoda and one Cestoda. The factors analysed had different influences on the different parasitic communities of each host species. It was possible to determine the dissimilarity between host populations based on their parasitic communities, and it was observed that the host species itself represented the most important factor in the structuring of helminth communities. The information recorded here converges with other results obtained in different studies with lizards, but points to patterns in the helminth community that differ from those observed in other areas of the Caatinga. The results obtained reveal complex patterns of association between parasites and hosts, demonstrating the existence of ecological relationships that can be shaped by specific factors.
Using a variation of Woodin’s $\mathbb {P}_{\mathrm {max}}$ forcing, we force over a model of the Axiom of Determinacy to produce a model of ZFC containing a very strongly increasing sequence of length $\omega _{2}$ consisting of functions from $\omega $ to $\omega $. We also show that there can be no such sequence of length $\omega _{4}$.