How sulfur is transferred from subducting slabs to the mantle and returned to the surface is central to understanding sulfur cycling in subduction zones. Arc magmas and volcanic gasses are commonly enriched in 34S relative to the mantle, a signature widely attributed to slab-derived sulfur inputs. Sulfide saturation and segregation are widespread during magma generation and differentiation, yet their effects on sulfur isotope fractionation remain poorly constrained. Here we use high-pressure experiments at 0.7–1.5 GPa and 1050–1400 °C to quantify sulfur isotope fractionation between sulfide liquid, monosulfide-solid-solution (MSS), and silicate melts over oxygen fugacities ranging from ∼FMQ−2 to FMQ+1.5. We find that sulfide–silicate melt fractionation is strongly controlled by temperature and oxygen fugacity. Sulfide liquid–silicate melt fractionation (∆34SSul‒Sil) ranges from −1.8 to +0.07‰, whereas MSS–silicate melt fractionation (∆34SMSS‒Sil) ranges from −2.8 to −0.03‰, with the largest fractionation occurring under oxidized conditions. Fractionation approaches zero at high temperatures and reduced conditions typical of mid-ocean ridge basalts, consistent with the near-mantle δ34S values of natural MORBs. In contrast, under oxidized arc conditions, sulfide segregation preferentially removes isotopically light sulfur and progressively enriches residual melts in 34S. Applying our experimentally determined fractionation factors to arc magma differentiation shows that residual melt δ34S can increase by up to ∼8‰, demonstrating that sulfide segregation can make a substantial contribution to the positive δ34S signatures observed in arc magmas, volcanic gasses, and continental crust. Our results demonstrate that magmatic sulfide segregation can substantially modify primary sulfur isotope signatures and therefore needs to be considered when using sulfur isotopes to quantify slab-derived sulfur fluxes. This mechanism can generate elevated δ34S in arc systems without necessarily requiring isotopically heavy sulfur inputs from subducting slabs.
Background Climate change places increasing pressure on health systems. They must both reduce their negative impact on the environment and strengthen resilience to climate-related risks. Objective To synthesize and map the evidence from systematic reviews on the scope and effectiveness of climate change mitigation and adaptation actions in health systems. Methods An umbrella review of systematic reviews examining health system responses to climate change was conducted. The review followed the Joanna Briggs Institute methodological guidelines and adhered to the PRISMA checklist. The included systematic reviews had to meet two overarching criteria: at least two databases were searched, and a predefined instrument was used to assess the quality or risk of bias of the included studies. Results Forty-six systematic reviews published between 2020 and 2026 were included, covering 1,175 individual studies. Most reviews (41/46) focused exclusively on mitigation strategies, with evidence concentrated around major greenhouse gas emission hotspots: surgical procedures; radiology; pharmaceuticals; solid waste; and transportation of patients and staff. Across these areas, some mitigation strategies were associated with environmental and economic co-benefits, although the underlying evidence was heterogeneous and often of low to moderate quality. In contrast, only a small number of reviews addressed climate adaptation and health system resilience. Conclusions Existing evidence provides practical guidance on effective climate mitigation actions. The limited number of systematic reviews on climate adaptation highlights a gap in the evidence base. Translating mitigation evidence into clinical guidelines and policies and strengthening research on adaptation could support more systematic climate action in health systems.
The evaluation of explainable AI (XAI) approaches often relies on three families of methods: subjective measures (e.g., questionnaires on trust or satisfaction), objective measures (e.g., task performance metrics), and mathematical metrics (e.g., for faithfulness). Yet, it remains unclear how these families align or diverge in practice. In a preregistered between-subjects study (N =166), we use three established saliency map techniques (LIME, Grad-CAM, Guided Backpropagation) as a testbed to examine this issue. We find that each family of methods leads to different conclusions: participants reported no differences in trust or satisfaction, Grad-CAM improved user performance, while mathematical metrics favored Guided Backpropagation. At the same time, mathematical metrics were only partially related to user performance, and these relationships were sometimes counterintuitive. Our findings highlight the methodological importance of comparing subjective, objective, and mathematical approaches when evaluating XAI, illustrating both tensions and aspects that are aligned. We discuss implications for XAI evaluation frameworks.
Research indicates that the fashion industry can be made more environmentally friendly by introducing a closedloop economy - also known as a circular economy - and implementing sustainable business models in areas such as clothing resale, rental, repair, and remake. Secondhand clothing is the sector to which research attributes the greatest potential for success in introducing new sustainable business models. This study examines the secondhand subscription box and eleven potential determinants from the secondhand fashion consumption literature. It complements a constraint-based approach (Necessary Condition Analysis - NCA) with an effect-based approach (regression analysis) to identify the necessary-but-not-sufficient conditions and the key (regression) factors shaping purchase intention. Using a sample of 215 German participants, we found that most determinants are necessity-based bottlenecks. They must be present and reach a certain threshold. Some are also key factors that drive purchase intention. The relevance of the determinants varies across sub-groups. This has implications for both academia and practice in designing secondhand subscription boxes. However, the study reveals that the determinants are context-dependent and no general principle can be transferred to other circular economy or sustainable consumption contexts.
During the energy crisis in 2022, electricity prices in Germany soared to unprecedented levels. To explore the drivers of the high electricity prices, we develop an electricity dispatch model that simulates hourly equilibrium prices under the assumption of perfect competition. We then extend this model to account for firms exercising market power. By comparing the outcomes of the perfect competition and Cournot competition models with actual market data, we demonstrate that market power may have contributed to higher prices during the crisis, elevating them beyond what rising input costs alone would justify.
