This paper presents numerical results for Rayleigh–Bénard convection with suspended particles at Rayleigh numbers $Ra=10^7$ and $10^8$, and unit Prandtl number. Accounting for their finite size makes it possible to investigate in detail the mechanism by which the particles, which are 10 % heavier than the fluid, get resuspended after settling, thus maintaining a two-phase circulating flow. It is shown that an essential component of this mechanism is the formation of particle accumulations, or ‘dunes’, on the bottom of the Rayleigh–Bénard cell. Ascending plumes become localised on these dunes. Particles are dragged up the dune slopes, and when they reach the top, are entrained into the rising plumes. Direct resuspension of particles from the cell bottom, if it happens at all, is very rare. For $Ra=10^7$, aspect ratios (width/height) $\Gamma =1,2,4$ are considered. It is found that in these and in the other cases simulated, at steady state, a single dune evolves, the largest linear dimension of which is comparable to the cell size. A remarkable consequence is that even at the low volume fraction considered here, 3.27 %, the particles are able to structure the flow and to determine the size and position of the largest ascending plumes. Their effect on the Nusselt number, however, remains small. This and other results are explained on the basis of the ratio of the cell-bottom viscous boundary-layer thickness to the particle diameter.

We formulate Guo–Jacquet type fundamental lemma conjectures and arithmetic transfer conjectures for inner forms of $GL_{2n}$. Our main results confirm these conjectures for division algebras of invariant $1/4$ and $3/4$.

Microbial O2 production via oxygenic photosynthesis was vital in oxygenating the Earth’s surface environment during the Great Oxygenation Event (GOE) ca. 2.5 to 2.3 billion years ago. However, geochemical, paleontological and genomic data suggest the emergence of oxygenic photosynthesis precedes the GOE by at least 500 million years. This demonstrates that the first appearance of microbial O2 in the environment cannot explain the timing of atmospheric oxygenation. Instead, the GOE was facilitated by Earth’s geodynamic evolution, expanding cyanobacterial habitats and the changing redox state of the mantle, decreasing the abundance of reduced surface rocks, volcanic gases and aqueous solutes. These trends ultimately resulted in magnified O2 production rates and diminished O2 consumption rates. Thus, the GOE can be understood as a misbalance between O2 sources and sinks. One of the most critical O2 sinks on modern Earth is microbial O2 consumption via aerobic respiration, and accumulating evidence suggests its emergence well before the GOE. However, the role of aerobic microorganisms as an O2 sink delaying the GOE remains poorly explored. Here, we review the redox evolution of Earth’s mantle and surface environments, as well as the Archean evolution of aerobic microbial metabolisms. Oxygenic photosynthesis released O2 to the environment, but the secular oxidation of the solid Earth was critical in allowing O2 accumulation. Aerobic respiration expanded in response to the GOE, but our survey suggests it could have been a critical O2 sink even earlier. Hence, aerobic respiration can be seen as geobiological feedback to changes in the Earth system from deep in the mantle up to the surface. However, the timing and rate of O2 consumption by aerobic respiration before the GOE remain poorly constrained. We conclude by highlighting open questions and future research directions to understand the role of the aerobic O2 sink in delaying the GOE.

Many young people feel distressed about climate change, and pessimistic about what the future holds. Gaps in education about climate change contribute to limited understanding of opportunities for climate mitigation and adaptation, and to a pervasive “discourse of doom.” Here we describe a “game for change” co-designed by climate and education researchers and young people, that aims to shift narratives about climate changed futures toward an active, adaptation-oriented focus.

The Heat Is On is designed to be played by high school classes. Set in 2050, the game takes place on a fictional island called “Adaptania.” Teams of students play the role of town councillors in communities facing the same challenges that Australian towns are experiencing as the climate heats up, including flooding, heatwaves, bushfires, inequality, health issues and economic challenges. By focussing on decision-making for adaptation and resilience, The Heat Is On enables participants to envision climate-changed futures in which communities can thrive. Students learn how to plan and collaborate to prepare for diverse and cascading impacts of climate hazards. We explore the potential for games in climate education, focussing on The Heat Is On as a case study, and share initial learnings from its development and implementation in schools.

We present a versatile framework that employs Physics-Informed Neural Networks (PINNs) to discover the entropic contribution that leads to the constitutive equation for the extra-stress in rheological models of dilute polymer solutions. In this framework the training of the neural network is guided by an evolution equation for the conformation tensor, which is GENERIC-compliant. We compare two training methodologies for the data-driven PINN constitutive models: one trained on data from the analytical solution of the Oldroyd-B (OB) model under steady-state rheometric flows (PINN-rheometric), and another trained on in silico data generated from computational fluid dynamics (CFD) simulations of complex flow around a cylinder that use the OB model (PINN-complex). The capacity of the PINN models to provide good predictions is evaluated by comparison with CFD simulations using the underlying OB model as a reference. Both models are capable of predicting flow behaviour in transient and complex conditions; however, the PINN-complex model, trained on a broader range of mixed-flow data, outperforms the PINN-rheometric model in complex flow scenarios. The geometry agnostic character of our methodology allows us to apply the learned PINN models to flows with topologies different from those used for training.

The next-generation radio astronomy instruments are providing a massive increase in sensitivity and coverage, largely through increasing the number of stations in the array and the frequency span sampled. The two primary problems encountered when processing the resultant avalanche of data are the need for abundant storage and the constraints imposed by I/O, as I/O bandwidths drop significantly on cold storage. An example of this is the data deluge expected from the SKA Telescopes of more than 60 PB per day, all to be stored on the buffer filesystem. While compressing the data is an obvious solution, the impacts on the final data products are hard to predict. In this paper, we chose an error-controlled compressor – MGARD – and applied it to simulated SKA-Mid and real pathfinder visibility data, in noise-free and noise-dominated regimes. As the data have an implicit error level in the system temperature, using an error bound in compression provides a natural metric for compression. MGARD ensures the compression incurred errors adhere to the user-prescribed tolerance. To measure the degradation of images reconstructed using the lossy compressed data, we proposed a list of diagnostic measures, exploring the trade-off between these error bounds and the corresponding compression ratios, as well as the impact on science quality derived from the lossy compressed data products through a series of experiments. We studied the global and local impacts on the output images for continuum and spectral line examples. We found relative error bounds of as much as 10%, which provide compression ratios of about 20, have a limited impact on the continuum imaging as the increased noise is less than the image RMS, whereas a 1% error bound (compression ratio of 8) introduces an increase in noise of about an order of magnitude less than the image RMS. For extremely sensitive observations and for very precious data, we would recommend a $0.1\%$ error bound with compression ratios of about 4. These have noise impacts two orders of magnitude less than the image RMS levels. At these levels, the limits are due to instabilities in the deconvolution methods. We compared the results to the alternative compression tool DYSCO, in both the impacts on the images and in the relative flexibility. MGARD provides better compression for similar error bounds and has a host of potentially powerful additional features.

An effective and just Financial Mechanism will be crucial to the success of the Global Plastic Treaty. The content in the latest Chair’s Text from INC-5.1 on finance (primarily in Article 11) could be strengthened to avoid replicating shortcomings in existing financing models, which have often been insufficient and have not always provided the necessary resources for global sustainable development. Experiences with climate finance mechanisms reveal a pattern of misdesign that needs to be addressed. The current Article 11 reflects the deep divisions evident in the two main proposals tabled at INC-5.1 in November 2024. In the light of past precedents and tensions, we argue that several core design principles related to scope, scale and social and health considerations could ensure that the Global Plastics Treaty’s Financial Mechanism supports just, ambitious and transformative global action on plastic pollution. Furthermore, we argue that several elements in the current treaty text may undermine the design and implementation of an effective and just Financial Mechanism for the future Global Plastics Treaty. These risks include overemphasizing waste management; missing connections between finance and other measures in the treaty; risks of not addressing the most effective responses; not adequately addressing plastic leakage, releases and emissions; sustaining financial investments in techno-economic lock-ins lacking sufficient safety and sustainability criteria, standards and monitoring requirements and the prospect of plastic credits, which risks repeating past false solutions. There is an opportunity for the treaty to overcome these challenges with a financial mechanism that addresses overproduction and incentivizes safer, more sustainable, accessible and cost-effective upstream solutions.

What does it mean to be a public Catholic institution in Canada? How does this Catholic identity evolve with the secularisation and diversification of society, and with the rising awareness of the complicated legacy of Catholicism and colonisation in Canada? This article explores those questions drawing on document analysis and interviews with staff working in Catholic health care. Taking a legal pluralist approach, it documents how Catholic health-care institutions navigate between transnational canon laws and ethics, and human rights law. Catholic health care is situated in a web of national and transnational legal regimes. We argue that this navigation takes different forms to adapt to societal changes, such as the authorization of Medical Assistance in Dying (MAiD). This article speaks directly to how Christianity continues to play a subtle, but still constant presence in Canadian Catholic hospitals, and debunks tropes that construct relationships between state and religion as one of clear separation.

The integration of computational methods into psychiatry presents profound ethical challenges that extend beyond existing guidelines for AI and healthcare. While precision medicine and digital mental health tools offer transformative potential, they also raise concerns about privacy, algorithmic bias, transparency, and the erosion of clinical judgment. This article introduces the Integrated Ethical Approach for Computational Psychiatry (IEACP) framework, developed through a conceptual synthesis of 83 studies. The framework comprises five procedural stages – Identification, Analysis, Decision-making, Implementation, and Review – each informed by six core ethical values – beneficence, autonomy, justice, privacy, transparency, and scientific integrity. By systematically addressing ethical dilemmas inherent in computational psychiatry, the IEACP provides clinicians, researchers, and policymakers with structured decision-making processes that support patient-centered, culturally sensitive, and equitable AI implementation. Through case studies, we demonstrate framework adaptability to real-world applications, underscoring the necessity of ethical innovation alongside technological progress in psychiatric care.