Let $G \leqslant \mathrm {Sym}(\Omega )$ be a finite transitive permutation group and recall that an element in G is a derangement if it has no fixed points on $\Omega $. Let $\Delta (G)$ be the set of derangements in G and define $\delta (G) = |\Delta (G)|/|G|$ and $\Delta (G)^2 = \{ xy \,:\, x,y \in \Delta (G)\}$. In recent years, there has been a focus on studying derangements in simple groups, leading to several remarkable results. For example, by combining a theorem of Fulman and Guralnick with recent work by Larsen, Shalev and Tiep, it follows that $\delta (G) \geqslant 0.016$ and $G = \Delta (G)^2$ for all sufficiently large simple transitive groups G. In this paper, we extend these results in several directions. For example, we prove that $\delta (G) \geqslant 89/325$ and $G = \Delta (G)^2$ for all finite simple primitive groups with soluble point stabilisers, without any order assumptions, and we show that the given lower bound on $\delta (G)$ is best possible. We also prove that every finite simple transitive group can be generated by two conjugate derangements, and we present several new results on derangements in arbitrary primitive permutation groups.

Actuaries must model mortality to understand, manage and price risk. Continuous-time methods offer considerable practical benefits to actuaries analysing portfolio mortality experience. This paper discusses six categories of advantage: (i) reflecting the reality of data produced by everyday business practices, (ii) modelling rapid changes in risk, (iii) modelling time- and duration-varying risk, (iv) competing risks, (v) data-quality checking and (vi) management information. Specific examples are given where continuous-time models are more useful in practice than discrete-time models.

Competing and complementary risk (CCR) problems are often modelled using a class of distributions of the maximum, or minimum, of a random number of independent and identically distributed random variables, called the CCR class of distributions. While CCR distributions generally do not have an easy-to-calculate density or probability mass function, two special cases, namely the Poisson–exponential and exponential–geometric distributions, can easily be calculated. Hence, it is of interest to approximate CCR distributions with these simpler distributions. In this paper, we develop Stein’s method for the CCR class of distributions to provide a general comparison method for bounding the distance between two CCR distributions, and we contrast this approach with bounds obtained using a Lindeberg argument. We detail the comparisons for Poisson–exponential, and exponential–geometric distributions.

We prove a functional transcendence theorem for the integrals of algebraic forms in families of algebraic varieties. This allows us to prove a geometric version of André’s generalization of the Grothendieck period conjecture, which we state using the formalism of Nori motives.

More precisely, we prove a version of the Ax–Schanuel conjecture for the comparison between the flat and algebraic coordinates of an arbitrary admissible graded polarizable variation of integral mixed Hodge structures. This can be seen as a generalization of the recent Ax–Schanuel theorems of [13, 18] for mixed period maps.

This special issue focuses on the many roles that context plays in neural machine translation and the evaluation of machine translation. It includes a survey of the current state of research related to context in machine translation and machine translation evaluation, along with three papers that focus on a variety of topics related to evaluation. Together, these highlight the wide range of topics in this area, and its increasing relevance as high-quality machine translation becomes increasingly common in a variety of settings.

In this paper, frontal variations and surface area changes for each of the years 2017–2023 are assessed for 277 Swedish glaciers, of which the majority is contained within the Randolph Glacier Inventory 7.0. Mapping of all Swedish glaciers became possible by combining Sentinel-2 imagery, semi-automated mapping procedures and the open-source Margin Change Quantification Tool (MaQiT). In addition, manual mapping was performed at a subset of 22 glaciers historically associated with the Swedish Front Variation Program. At four of those, mapping accuracy was assessed by contrasting Sentinel-2 mapped fronts to fronts mapped in situ using Global Navigation Satellite System (GNSS), a total station and an uncrewed aerial vehicle. Results show widespread retreat of all Swedish glaciers, with cumulative frontal variation amounting on average to −55.6 m during 2017–2023 or −9.3 m a−1. Swedish glaciers had a total area of ∼237 km2 in 2017 and of 210 km2 in 2023. The reduction by ∼27 km2 corresponds to a loss of 11% with respect to the areal extent in the year 2017 but varies across regions. It is also almost as large as the combined area loss of Swedish glaciers in the preceding 15 years (∼31 km2, 2002–2017).

Cognitive therapy for post-traumatic stress disorder (PTSD) is recommended in a range of national and international guidelines. This clinical guidance paper specifically focuses on cognitive therapy for PTSD (CT-PTSD) where racism has been part of the index trauma event(s). It aims to support CBT therapists to maintain fidelity to the CT-PTSD model but also ensure that racism is integrated into the formulation and interventions in ways that are sensitive and validating. It explores barriers to this occurring ranging from societal factors (e.g. ongoing racism, discouragement from discussing racism), to therapist factors (e.g. lack of understanding of racism, lack of own understanding of racialised identity, anxiety, lack of knowledge, skills and confidence) and patient factors (e.g. shame, fear of therapist response). The paper aims to provide guidance on how these can be addressed alongside case illustrations and practical considerations for therapists and supervisors.

In this catalogue, we present the results of a systematic study of 199 short gamma-ray bursts (GRBs) detected by Konus-Wind between 1 January 2011 and 31 August 2021. The catalogue extends the Second Catalogue of short GRBs covering the period 1994–2010 by ten years of data. The resulting Konus-Wind short GRB sample includes 494 bursts. From temporal and spectral analyses of the sample, we provide the burst durations, spectral lags, estimates of the minimum variability timescales, rise and decay times, the results of spectral fits with three model functions, the total energy fluences, and the peak energy fluxes of the bursts. We present statistical distributions of these parameters for the complete set of 494 short GRBs detected in 1994–2021. We discuss in detail the properties of the bursts with extended emission in the context of the whole short GRB population. Finally, we consider the results in the context of the Type I (merger-origin)/Type II (collapsar-origin) classification and discuss the extragalactic magnetar giant flare subsample.

This article extends recent insights from new institutional economics to explore the relevance of the concept of meso-institutions. It does so through the exploration of the case of the Brazilian Forest Code, pointing out how and why meso-institutions play a key role in making public policies effective. More specifically, our study shows how crucial is the complete fulfilling of the functions characterising meso-institutions – namely translation, monitoring, and enforcement, to implement regulations and determine their effectiveness. Lessons are drawn regarding the complexities inherent in the creation, implementation, and operationalisation of rules across a multilayered institutional environment.

Language mixing is a common phenomenon in the language input of bilingual children. However, the relation between the frequency of parental language mixing and children’s language development remains unclear. The present study investigates the relation between language mixing as observed in daylong audio recordings (LENA) and as reported by parents in the questionnaire for Quantifying Bilingual Experience (Q-BEx) and children’s language outcomes in the majority and minority language. Participants were 52 3-to-5-year-old Polish-Dutch and Turkish-Dutch children in the Netherlands and Bayesian informative hypothesis evaluations were applied. In 14 out of 15 regression analyses, the LENA and Q-BEx measures yielded similar associations with children’s language outcomes. Parental language mixing was not related to majority language outcomes, but a negative relation was found with expressive vocabulary in the minority language. Longitudinal studies are needed to pinpoint the directionality of this negative relation.

This paper presents a pedagogical experiment in the form of a fictional podcast episode that “aired” in January 2025, featuring Tim Winton’s climate fiction novel Juice (2024). Emerging from a dialogical reading collaboration between three interdisciplinary “scholars, resisters and ordinary grafters” (Winton, 2024, p.116) — Rumen Rachev, Jo Pollitt, and Emma Nicoletti — the paper and podcast operate together through a method we term papercast, centring on three key themes: clouds, atmospheric frictions, and the significance of critically engaging with climate fiction, specifically Juice, amid ongoing climate instability. Simultaneously paper and podcast (papercast), we invite the reader to “listen” visually to the printed material that follows. Through discussion and excerpts from Clouds Running Out of Juice, a creative non-fiction episode of the fictional Ecosophic Generator podcast, the work incorporates AI-generated responses from “listeners” who inhabit the liminal space between present imaginings and future realities. This papercast emerged through asynchronous reading practices and collaborative dialogue, culminating in a three-way conversation that traverses multiple theoretical terrains. Rachev’s investigation as an atmospheric economist into the future-proofing of clouds, Pollitt’s choreographic exploration of everyday weather and experiences of weathering instability, and Nicoletti’s examination of human-atmospheric binaries collectively generate productive tensions between scientific knowledge and creative uncertainty.

As governments prepare for the decisive round of negotiations for the global plastics treaty in August 2025, trade remains a largely overlooked yet indispensable element in shaping an effective and equitable agreement. We argue that trade, spanning plastic feedstocks, resins, products, and waste, forms the connective tissue of the plastics economy and that it must be embedded in the treaty’s architecture. Drawing on global trade data, country cases, and precedent from multilateral environmental agreements, we demonstrate how trade both drives plastic pollution and can serve as a lever for circularity and sustainability. We outline the asymmetries in global plastics trade and their implications for equity and implementation, especially for small and import-dependent states. The article proposes a suite of actionable recommendations for INC-5.2, including trade-related transparency, WTO-aligned treaty provisions, and dedicated capacity-building support. By integrating trade governance into the plastics treaty, negotiators can build an agreement that is both environmentally ambitious and structurally sound.

Are political activists driven by instrumental motives such as making a career in politics or mobilizing voters? We implement two natural field experiments in which party activists are randomly informed that canvassing is i) effective at mobilizing voters, or ii) effective for enhancing activists’ political careers. We find no effect of the treatments on activists’ intended and actual canvassing behaviour. The null finding holds despite a successful manipulation check and replication study, high statistical power, a natural field setting, and an unobtrusive measurement strategy. Using an expert survey, we show that the null finding shifted Bayesian posterior beliefs about the treatment’s effectiveness toward zero. The evidence thus casts doubt on two popular hypothesized instrumental drivers of political activism – voter persuasion and career concerns – and points toward expressive benefits as more plausible motives.

Plastics and climate change are inseparable issues, both materially and geopolitically. Plastics are derived almost entirely from fossil fuels and have an enormous greenhouse gas footprint. Aligning with the Paris Agreement requires rapid, dramatic decreases in plastic production, contravening the industry’s plans to continue expanding production. The oil, gas and petrochemical industry wields substantial power in both the climate and plastics treaty negotiations and has used that power to stymie progress in both. Rather than repeat the failures of the climate negotiations, plastics negotiators should seek to create a “plastics club” for ambitious action.