In the context of the ongoing war in Ukraine, it is striking that there have been many references to resilience, including by Western and Ukrainian leaders. This article is precisely about their use of resilience discourse, and it makes two important contributions to existing scholarship on resilience in conflict settings. First, drawing on Ish-Shalom’s idea of ‘concepts at work’ and analysing a selection of speeches and policy statements (by Western leaders and President Volodymyr Zelensky) that specifically refer to resilience, it demonstrates that resilience is a significant ‘concept at work’ in the war, making certain forms of international and domestic politics possible. Second, while research on resilience frequently discusses different ways that the concept has been defined and approached in fields such as engineering, ecology, and psychology, this article highlights that diverse framings of resilience have become entangled as the concept is ‘at work’ in the war in Ukraine. More specifically, its analysis makes prominent the fusion of different resiliences at different levels – from the individual to the systemic – discursively working together for particular political ends. In this way, it offers a novel way of thinking multi-systemically about resilience and, by extension, about resilience and complexity.

Motivated by the work initiated by Chapman [‘Determinants of Legendre symbol matrices’, Acta Arith. 115 (2004), 231–244], we investigate some arithmetical properties of generalised Legendre matrices over finite fields. For example, letting $a_1,\ldots ,a_{(q-1)/2}$ be all the nonzero squares in the finite field $\mathbb {F}_q$ containing q elements with $2\nmid q$, we give the explicit value of the determinant $D_{(q-1)/2}=\det [(a_i+a_j)^{(q-3)/2}]_{1\le i,j\le (q-1)/2}$. In particular, if $q=p$ is a prime greater than $3$, then

$$ \begin{align*}\bigg(\frac{\det D_{(p-1)/2}}{p}\bigg)= \begin{cases} 1 & \mbox{if}\ p\equiv1\pmod4,\\ (-1)^{(h(-p)+1)/2} & \mbox{if}\ p\equiv 3\pmod4\ \text{and}\ p>3, \end{cases}\end{align*} $$

where $(\frac {\cdot }{p})$ is the Legendre symbol and $h(-p)$ is the class number of $\mathbb {Q}(\sqrt {-p})$.

The $d$-process generates a graph at random by starting with an empty graph with $n$ vertices, then adding edges one at a time uniformly at random among all pairs of vertices which have degrees at most $d-1$ and are not mutually joined. We show that, in the evolution of a random graph with $n$ vertices under the $d$-process with $d$ fixed, with high probability, for each $j \in \{0,1,\dots,d-2\}$, the minimum degree jumps from $j$ to $j+1$ when the number of steps left is on the order of $\ln (n)^{d-j-1}$. This answers a question of Ruciński and Wormald. More specifically, we show that, when the last vertex of degree $j$ disappears, the number of steps left divided by $\ln (n)^{d-j-1}$ converges in distribution to the exponential random variable of mean $\frac{j!}{2(d-1)!}$; furthermore, these $d-1$ distributions are independent.

While the origins and consequences of populist attitudes in adults are being studied extensively, it is still unknown when populist attitudes might emerge in a person’s life. Drawing on the existing literature on political socialization, we focus on populist attitudes during adolescence and explore the contributing role of negative relationships with parents, peers, and teachers. We provide the first comprehensive analysis of populist attitudes among a representative sample of children aged 12 to 18 (mean: 14.66 years) using a unique dataset gathered through interviews conducted in schools in Austria, Germany, and Switzerland (n=3,123). Our findings reveal a strong association between perceived unjust teacher behavior and the level of populist attitudes in adolescents, while the connection of peers and parents with populist attitudes appears to be limited. Further analyses using panel data from the UK support these findings.

We find that division managers who are connected to the CEO are substantially less likely than others to depart from the firm and are more likely to be promoted. Connected managers are protected when performance is poor, and they display no special ability to improve performance given this protection. Connections matter more in weak governance/incentive environments, and the external labor market and stock market appear skeptical of connected managers’ talents. While much of the evidence suggests inefficient favoritism, connected managers are protected more in peripheral segments, suggesting a possible efficiency benefit in helping to resolve intrafirm information problems.

Singularly perturbed ordinary differential equations often exhibit Stokes’ phenomenon, which describes the appearance and disappearance of oscillating exponentially small terms across curves in the complex plane known as Stokes lines. These curves originate at singular points in the leading-order solution to the differential equation. In many important problems, it is impossible to obtain a closed-form expression for these leading-order solutions, and it is therefore challenging to locate these singular points. We present evidence that the analytic leading-order solution of a linear differential equation can be replaced with a numerical rational approximation using the adaptive Antoulas–Anderson (AAA) method. Despite such an approximation having completely different singularity types and locations, we show that the subsequent exponential asymptotic analysis accurately predicts the exponentially small behaviour present in the solution. For sufficiently small values of the asymptotic parameter, this approach breaks down; however, the range of validity may be extended by increasing the number of poles in the rational approximation. We present a related nonlinear problem and discuss the challenges that arise due to nonlinear effects. Overall, our approach allows for the study of exponentially small asymptotic effects without requiring an exact analytic form for the leading-order solution; this permits exponential asymptotic methods to be used in a much wider range of applications.

This is a case of a 13-year-old male with frequent premature ventricular contractions with QRS configurations of the left superior axis and left bundle branch block, which originated from the posterior–superior process of the left ventricle. Premature ventricular contractions were successfully eliminated by delivering radiofrequency energy to the inferior wall of the right atrium without causing either junctional rhythm or atrioventricular block. Ventricular arrhythmias originating from this site have been sporadically reported in adults; however, this is the first report in a child.

We show that for $n \neq 1,4$, the simplicial volume of an inward tame triangulable open $n$-manifold $M$ with amenable fundamental group at infinity at each end is finite; moreover, we show that if also $\pi _1(M)$ is amenable, then the simplicial volume of $M$ vanishes. We show that the same result holds for finitely-many-ended triangulable manifolds which are simply connected at infinity.

The evaluation of the effects of early starvation and feeding on survival and growth in the early stages of the life cycle of ornamental marine caridean shrimp species is fundamental to establish adequate feeding protocols in their culture. In this study, we determine the nutritional vulnerability in the early larval stages of ornamental shrimp Lysmata ankeri exposed to different periods of starvation or feeding. The larvae were separated into three groups (zoea I-ZI, zoea II with ZI fed, and zoea II with ZI unfed) and subjected to two experiments: (1) point-of-no-return (PNR), comprising one or two days of initial starvation followed by feeding; and (2) point-of-reserve-saturation (PRS), comprising one or two days of initial feeding followed by starvation. Each experiment was still composed of two control groups: continuous feeding and continuous starvation. Larvae tolerated some periods of starvation, with a high PNR value (2.00) and low PRS (0.50). Longer periods of starvation influenced both growth and survival rates in zoea II stages. The nutritional vulnerability index for zoea I was 0.25, which represents a low dependence on food supply. In this study, it was observed that ornamental shrimp L. ankeri larvae hatch with energy reserves, presenting facultative primary lecithotrophy, in which they are able to moult from zoea I to zoea II using such reserves in the absence of food. In this sense, the early larvae stages (zoeas I and II) can tolerate a certain period of starvation, indicating the great potential of this species for aquaculture.

This study examined the effects of distributed practice on second language (L2) speech fluency development. A total of 116 Japanese L2 learners of English were randomly divided into experimental or control conditions. Learners assigned to the experimental groups engaged in four fluency training sessions either in a short-spaced (1-day interval) or long-spaced (7-day interval) condition. Although different learning trajectories were observed during the training phase, the posttests conducted 7 and 28 days after the training showed similar fluency gains for the two groups, indicating that short- and long-spaced conditions were equally effective for developing L2 fluency. The current study extends the line of research in distributed practice and task repetition for L2 fluency development.