Yaw control can effectively enhance wind farm power output, but the vorticity distribution and coherent structures in yawed turbine wakes remain poorly understood. We propose a physical model capable of accurately predicting tip vortex dynamics from their generation to destabilisation. This model integrates a point vortex framework with advanced blade element momentum theory and vortex cylinder theory for yawed turbines. Comparisons with large eddy simulations demonstrate that the model effectively predicts the vorticity distribution of tip vortices and the wake profile of yawed turbines. Finally, we employ sparsity-promoting dynamic mode decomposition to analyse the dynamics of the far wake. Our analysis reveals four primary mode types: (i) the averaged mode; (ii) shear modes; (iii) harmonic modes; and (iv) merging modes. Under yawed conditions, these modes become asymmetric, leading to interactions between the tip and root vortex modes. This direct interaction plays a critical role during the formation process of the counter-rotating vortex pair observed in yawed wakes.

Past research alerts to the increasingly unpleasant climate surrounding public debate on social media. Female politicians, in particular, are reporting serious attacks targeted at them. Yet, research offers inconclusive insights regarding the gender gap in online incivility. This paper aims to address this gap by comparing politicians with varying levels of prominence and public status in different institutional contexts. Using a machine learning approach for analyzing over 23 million tweets addressed to politicians in Germany, Spain, the United Kingdom, and the United States, we find little consistent evidence of a gender gap in the proportion of incivility. However, more prominent politicians are considerably and consistently more likely than others to receive uncivil attacks. While prominence influences US male and female politicians’ probability to receive uncivil tweets the same way, women in our European sample receive incivility regardless of their status. Most importantly, the incivility varies in quality and across contexts, with women, especially in more plurality contexts, receiving more identity-based attacks than other politicians.

Exchangeable partitions of the integers and their corresponding mass partitions on $\mathcal{P}_{\infty} = \{\mathbf{s} = (s_{1},s_{2},\ldots)\colon s_{1} \geq s_{2} \geq \cdots \geq 0$ and $\sum_{k=1}^{\infty}s_{k} = 1\}$ play a vital role in combinatorial stochastic processes and their applications. In this work, we continue our focus on the class of Gibbs partitions of the integers and the corresponding stable Poisson–Kingman-distributed mass partitions generated by the normalized jumps of a stable subordinator with an index $\alpha \in (0,1)$, subject to further mixing. This remarkable class of infinitely exchangeable random partitions is characterized by probabilities that have Gibbs (product) form. These partitions have practical applications in combinatorial stochastic processes, random tree/graph growth models, and Bayesian statistics. The most notable class consists of random partitions generated from the two-parameter Poisson–Dirichlet distribution $\mathrm{PD}(\alpha,\theta)$. While the utility of Gibbs partitions is recognized, there is limited understanding of the broader class. Here, as a continuation of our work, we address this gap by extending the dual coagulation/fragmentation results of Pitman (1999), developed for the Poisson–Dirichlet family, to all Gibbs models and their corresponding Poisson–Kingman mass partitions, creating nested families of Gibbs partitions and mass partitions. We focus primarily on fragmentation operations, identifying which classes correspond to these operations and providing significant calculations for the resulting Gibbs partitions. Furthermore, for completion, we provide definitive results for dual coagulation operations using dependent processes. We demonstrate the applicability of our results by establishing new findings for Brownian excursion partitions, Mittag-Leffler, and size-biased generalized gamma models.

Linear hydroelastic waves propagating in a frozen channel are investigated. The channel has a rectangular cross-section, finite depth and infinite length. The liquid in the channel is an inviscid, incompressible liquid and covered with ice. The ice is modelled as a thin elastic plate of variable thickness clamped to the channel walls. The thickness is constant along the channel length and varying across it. The flow induced by ice deflections is potential. The problem reduced to a problem of wave profiles across the channel and was solved using a piecewise linear approximation of a shape of the thickness. Normal modes are calculated to ensure continuous deflections, slopes, bending stresses and shear forces in the ice plate. Two thickness distributions are studied: in Case I, the thickness is constant at a middle segment and linearly increases at edge segments over the channel’s width; in Case II, the thickness linearly decreases at the edge segments. In Case I, there is one segment with the thin part of the ice cover where, as expected, the oscillations of the ice plate will be concentrated. In Case II, there are two such areas, separated by the middle segment with the thick part of the ice cover. Dispersion relations, phase and group velocities, wave profiles and strain distributions in the ice plate are studied. Results show that the properties of periodic hydroelastic waves are significantly influenced by the ice thickness distribution across the channel.

Take two positions, both of which we take to be popular ways of thinking about law. First, some norm N is part of the law only if, and in virtue of, N being ultimately recognized or validated by the rule of recognition. Call this Hartian Orthodoxy. Second, statements about legal rights are best understood as claims about the existence of moral rights according to law. Call this legal perspectivalism. Here we show that the two are incompatible. Our argument is that, to account for certain arguments that mix legal and factual claims, perspectivalism must close the legal perspective according to some inference rule. As it happens, however, the only defensible candidates render perspectivalism incompatible with Hartian Orthodoxy.

We investigate the effect of streamwise and transverse rotation on the wake behind an elastically mounted sphere. Simulations are performed at a Reynolds number $Re=500$ over a range of reduced velocity $2\le U^{\ast }\le 12$, considering a low and high rotational speed (0.2 and 1), keeping the mass ratio $m^{\ast }=2$. Streamwise rotation yields a structural response akin to the non-rotating case, while transverse rotation triggers induced vibration at lower $U^{\ast }$ and sustains it across a wider range. Like the non-rotating case, the streamwise rotating sphere exhibits synchronous, high-amplitude vibration across the entire $U^\ast$ range, whereas for low transverse rotation, it is confined to $5\le U^{\ast }\le 6$. Cross-stream displacement of the sphere remains unaffected by streamwise rotation with increasing $U^{\ast }$. In contrast, it monotonically increases due to transverse rotation, driven by the Magnus force, as supported by our theoretical and numerical estimations. While the spiral shedding mode dominates at $\Omega _{x}=0.2$, twisted hairpin and twisted spiral modes emerge as the rotation rate is increased. On the other hand, we observe the hairpin (HP) mode, as seen in the non-rotating case, for low transverse rotation. The HP mode gives rise to the ring vortical mode at the far wake, and with an increase in $U^\ast$, the wake shows small-scale stretched threads and reconnected bridgelets. Wake fluctuations increase with a streamwise rotation that saturates at higher $U^{\ast }$ during synchronisation, while desynchronisation at dimensionless transverse rotation rate $\Omega _{z}=1$ induces intermittent low-amplitude vibration via the Magnus effect. Space–time reconstruction at the near wake shows an undisturbed helical vortex core at $\Omega _{x}=0.2$ and $U^{\ast }=5$, which bifurcates at $\Omega _{x}=1$ owing to the centrifugal-induced distortion. At $\Omega _{x}=1$ and $U^{\ast }=5$, the phase difference between $(y, C_{y})$ and $(z, C_{z})$ exhibits in-phase synchrony with occasional phase slips. The wake vortex remains unaffected by the transverse rotation of the sphere; however, a streamwise rotating sphere couples the wake, leading to a rotational lock-in. The wake rotation shifts from anti-clockwise to clockwise sense earlier (in $U^\ast$) at a lower rotation rate. The reduced velocity is seen to have a favourable effect on the transfer of the sphere’s rotational inertia onto the wake as the measured penetration depth increases with $U^{\ast }$. Insights from the present research will aid in understanding complex flow interactions in rotational systems, improving efficiency, stability and control in modern engineering applications.

Only months after starting as KPFA’s music director, Charles Amirkhanian launched the radio show Ode to Gravity in March 1970. The evocative name referred to his 1968 experimental theatre piece that involved dropping objects such as a marble and car fender into a circle of spectators. The radio programme similarly released a range of avant-garde music and sound objects over the airwaves, reflecting Amirkhanian’s preferred title as KPFA’s ‘Sound Sensitivity Information Director’. Informed by analyses of archival broadcasts and other primary sources, this article frames Ode to Gravity as a conceptual extension of the 1968 piece and long-running ‘sound sensitivity’ experiment that sought to make sense of the contemporary musical landscape by collecting and propagating sonic data. Ode to Gravity’s consciousness-raising mission broadly, and the changes in content and presentation style over its twenty-five-year history specifically, add further texture to our understanding of post-war avant-garde impulses in music and sound.

Why and how does Russia engage in the arms trade? Scholars have largely focused on why Russia participates in the arms trade, often neglecting the equally crucial question of how it conducts this trade. Yet understanding the mechanisms by which Russia promotes arms sales provides deeper insights into why it does so. While many portray Russia’s arms trade as driven by economic or strategic motivations, few examine the specific tools it employs, particularly defence counter-trade, which includes non-monetary barter, counter-purchase obligations, and industrial or technological investments (offsets). This paper fills that gap by offering an eight-decade perspective on Russian arms trade practices, drawing on data and case studies to uncover a more nuanced set of motives. Russia integrates economic and political objectives in its arms trade, seeking not only to out-compete Western suppliers but also to expand or regain influence in various regions, circumvent Western-imposed sanctions, secure access to valuable resources, and sustain its military capabilities. Although barter and technological cooperation have long been part of its trade practices, Russia has only recently adopted offset practices in a systematic way. By leveraging defence counter-trade, Moscow aims to stabilise, and potentially grow, its arms exports as global conditions shift.

Recent studies showed contradictory results with regard to the implementation of proactive language control during bilingual sentence production. To add novel evidence to this debate, the current study investigated the blocked language order effect, a measure of proactive language control that has previously only been examined in single-word production. More specifically, bilingual participants completed a network description task, using their L1 in Blocks 1 and 3 and their L2 in Block 2. Results showed increased language intrusions in Block 3 compared to Block 1. This pattern indicates that proactive language control can be implemented during bilingual sentence production.

Following [1], given cardinals $\kappa <\lambda $, we say $\kappa $ is a club $\lambda $-Berkeley cardinal if for every transitive set N of size $<\lambda $ such that $\kappa \subseteq N$, there is a club $C\subseteq \kappa $ with the property that for every $\eta \in C$, there is an elementary embedding $j: N\rightarrow N$ with $\mathrm {crit }(j)=\eta $. We say $\kappa $ is $\nu $-club $\lambda $-Berkeley if $C\subseteq \kappa $ as above is a $\nu $-club. We say $\kappa $ is $\lambda $-Berkeley if C is unbounded in $\kappa $. We show that under $\textsf {AD}^{+}$, (1) every regular Suslin cardinal is $\omega $-club $\Theta $-Berkeley (see Theorem 7.1), (2) $\omega _1$ is club $\Theta $-Berkeley (see Theorem 3.1 and Theorem 7.1), and (3) the ’s are $\Theta $-Berkeley – in particular, $\omega _2$ is $\Theta $-Berkeley (see Remark 7.5).

Along the way, we represent regular Suslin cardinals in direct limits as cutpoint cardinals (see Theorem 5.1). This topic has been studied in [31] and [4], albeit from a different point of view. We also show that, assuming $V=L({\mathbb {R}})+{\textsf {AD}}$, $\omega _1$ is not $\Theta ^+$-Berkeley, so the result stated in the title is optimal (see Theorem 9.14 and Theorem 9.19).

The present study relied on internet memes as a tool to possibly fight ageism and shape public views in a positive manner. Data collection took place between May and June 2024, recruiting 160 Israeli Arabs, aged 13 to 16, from 3 different schools. In total, 105 memes addressed ageism towards older people. Visual and written contents were described, followed by more interpretative analysis. The memes were classified into two main themes. The first concerned negative ageist stereotypes of older persons (n = 66). The second theme concerned attempts to combat ageism (n = 39). Even though students received explicit instructions to fight ageism via their meme production, most students produced memes which depicted older age and ageing in a negative stereotypical light. The study highlights the relatively high levels of ageism in this group of participants and points to areas needing further attention in future interventions to alleviate ageism. The present findings are important as they question the current thinking of the Arab population as characterized by familistic values of high levels of respect towards older persons.