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Age of the Acraman impact ejecta layer in the adelaide superbasin and Implications on clay-mineral provenance from the Rb–Sr systematics of middle Ediacaran shales
No full textThe Acraman bolide hit the Gawler Craton of South Australia in the middle Ediacaran. Debris from this impact punctuates the Ediacaran sequences of the Adelaide Superbasin and the eastern Officer Basin. Here we date an argillaceous Acraman impactite layer sampled from Arkaba Creek, in the Bunyeroo Formation of the Adelaide Superbasin at 585 ± 15 Ma (MSWD = 1.8, 2 σ error) using the in-situ Rb–Sr ICP-MS/MS technique that we interpret to date the impact event. The analyses have a radiogenic 87 Sr/ 86 Sr initial ratio of 0.7210 ± 0.0028 and elevated light rare earth element values. Shales from both above and below the impact horizon yielded ages significantly pre-dating deposition and are interpreted to reflect detrital input into the Bunyeroo Formation, which is consistent with previous petrographic studies. Intriguingly, all 10 shales analysed yielded Rb–Sr ages within error of each other, with a Tonian weighted mean age of 778 ± 17 Ma (MSWD = 0.83). This is interpreted to reflect a very similar clay mineral age provenance for these shales despite being found in samples over 600 km apart. A similar mix of detrital mineral ages cannot be discounted. However, considering the spatial distribution, an alternative interpretation that the age similarity reflects Tonian pedogenic clay formation on the Gawler Craton, is thought more likely.Alan S. Collins, Morgan L. Blades, Darwinaji Subarkah, Holly Cooke, Leslie Edwards, Chelsea Forbister, Jake Jolly, Jarred C. Lloyd, Sarah E. Gilbert, Stefan Lohr, Juraj Farkas, Victor Gosti
Time-domain analysis of an ice shelf in a bounded domain
No full textA time-domain model of an ice shelf interacting with ocean water in a finite domain is developed, which combines Kirchhoff–Love plate theory with the shallow-water wave equations. In particular, the domain is divided into an open-water region and a region in which the ocean is covered by an ice shelf. Boundary conditions, together with continuity conditions at the ice–water interface, lead to a nonlinear matrix eigenvalue problem, which is solved numerically to obtain the natural modes and frequencies of the system. These form the basis for reconstructing the transient response to wave forcing using a spectral method. Simulations show how wave packets excite multiple modes and generate interference patterns through boundary reflections. Since the method solves the initial value problem in a geometry containing both an open-ocean region and an ice-shelfcovered region, it provides a foundation for simulating sequential break-up of ice shelves due to wave-induced mechanical stresses, and contributes to broader efforts to model ice shelf disintegration under ocean forcing.Faraj Alshahrani, Michael Meylan and Ben Wilk
The need to understand the underlying mechanisms associated with mitochondrial therapies in assisted reproduction before further clinical trials are performed
No full textOlinePublOver a number of years, there has been growing interest in the introduction of more invasive ARTs, such as nuclear transfer, otherwise referred to as mitochondrial donation, and mitochondrial supplementation/transfer into clinical medicine. They have been proposed to overcome repeated failed fertilization or developmental arrest or to prevent carriers of mitochondrial DNA disease from having affected children. These technologies require considerable manipulation of the oocyte, which can affect its epigenetic programming that was established as it grew and developed into a fertilizable oocyte. Consequently, when a nucleus is transferred into an enucleated oocyte or pronuclei are transferred into an enucleated zygote, the nucleus must adapt to its new cytoplasmic environment in readiness for the waves of DNA demethylation and methylation that take place during preimplantation development. As a result, some key developmental gene networks are affected. Additionally, these approaches also affect patterns of mitochondrial DNA inheritance, with some embryos and offspring possessing mitochondrial DNA carried over into the oocyte with the nucleus, as well as the mitochondrial DNA from the donor oocyte. Similar outcomes result from the addition of extra mitochondrial DNA into oocytes through mitochondrial supplementation. We provide a background as to how these technologies evolved and discuss recent outcomes associated with clinical work so far undertaken within these approaches and their consequences for the offspring. We conclude that these technologies are not simply replacing or replenishing defective ooplasms with new or extra mitochondria but rather induce a series of genomic and epigenomic events that we do not yet fully understand. To our minds, these issues should be first addressed before clinical trials are continued.Justin C. St John and Raymond J. Rodger
Real-time bulk-density monitoring for rotary air concentration used in alluvial gold mining
No full textLink to a related website: https://orcid.org/0000-0002-6871-6027, ORCID profile - Asamoah, Richmond KomlaAlluvial gold mining entails extracting gold from sedimentary deposits in current and ancient riverbeds. It is widely regarded as the most eco-friendly approach to gold mining due to its minimised environmental footprint compared to underground and open-pit mining. Rotary air concentration (RAC), a novel classification method seen in this field, physically separates dense gold-bearing particles from low-density gangue materials, where particle density is the dominant factor distinguishing concentrates from tails, rather than particle size. However, the dry-processing nature of air classification and high-intensity feature of the concentrates discharge impose significant challenges in gauging particle density in real-time and there is a lack of costeffective commercial equipment in this regard, specifically for optimal closed-loop feedback control. This study resolves the problem with a new technique on the basis of vibration measurement. A prototype consisting of a mechanical probe and an accelerometer has been designed and built for inline installation along the RAC concentrates stream. Procedures to process vibration data in frequency domain are proposed. Laboratory experiments using samples from an Australian alluvial gold deposit have proven the proposed approach effective in monitoring bulk-density variation of RAC-classified concentrates stream in real-time
Using an ecological model to guide transformative place-based pathways to regional business disaster recovery
No full textThe escalating frequency, severity and scale of disasters and predicted more frequent epidemics and pandemics threatens the economic and social fabric of regional communities in Australia. This article reports on findings from two case studies conducted in South Australia that explored regional business recovery pathways following the Black Summer fires (2019/2020) and the COVID-19 pandemic. We used Bronfenbrenner’s ecological systems theory of human development to analyse data from 18 interviews with small business owners. We found that the linkages between systems are where the most effective support occurs and yet these linkages are often missing, under-resourced and captured by unhelpful definitions of resilience and self-reliance. We explored the complex mix of supports that already exist in communities, as well as supports delivered by different levels of government, to provide insights regarding the types and timing of these supports. Our findings contribute to developing place-based approaches to navigate pathways for regional businesses to recover and thrive post-disaster. Our findings are relevant beyond this study, providing guidance to those working with communities to foster transformative place- based recovery
Experimental and numerical investigation of shield tunnel segments reinforced with grouted channel steel under diverse damage scenarios
No full textAvailable online 2 December 2025As a key component of urban rail system, shield tunnels are susceptible to cracking and stiffness degradation, from which an urgent need for effective reinforcement arises. In this study, grouted channel steel (GCS) with bolted connections was assessed as a reinforcement strategy for damaged tunnel segments. Full-scale tests integrated with finite element simulations verified the reliability of the proposed modelling approach, as strong agreement was observed between simulated and experimental load–displacement responses and crack development. The deformation of reinforced segments proceeded through three stages: elastic, strengthening, and failure. The effectiveness of reinforcement was governed by the level of prior damage. Elastic stiffness declined progressively with increasing damage, whereas strengthening-stage stiffness remained stable. Stiffness enhancement was concentrated in the strengthening stage, reaching values up to sixteen times those of the elastic stage. Under service limit conditions, balanced stiffness improvements of 95–120 % were achieved across stages, and recovery after unloading reached 140–160 %. These results indicate that GCS reinforcement provides a robust means of restoring and extending the service life of shield tunnel segments in urban rail systems.Xun Wu, Jun H, Kan Huang, Xiangsheng Chen, Sidong Feng, Bin Huan
Enhancing healthcare worker mental health via artificial intelligence-driven work process improvements: a scoping review
No full textBackgroundHealthcare workers (HCWs) are exposed to higher rates of mental health issues, such as burnout, anxiety, cognitive overload, and stress, compared to the general population. These may be exacerbated by administrative activities like extensive paperwork and disintegrated work processes. The implementation of artificial intelligence (AI) in healthcare holds the potential to combat these challenges by streamlining workflow processes, lowering administrative load, and increasing efficiency. The role of AI in supporting HCWs' mental health is yet to be fully explored. This scoping review mapped the current evidence on how AI can enhance HCWs' mental health through workflow optimisation.MethodsThis scoping review was informed by best practice in the conduct and reporting of scoping reviews. A comprehensive search of academic and grey literature was performed without date restrictions. A two-stage dual screening process was employed using Covidence. A customised data extraction tool was developed to systematically extract data, which was then summarised descriptively.ResultsTwenty articles were included in the review, most of which were published between 2020 and 2024. These comprised empirical studies, literature reviews, position papers, as well as selected grey literature. The studies explored various AI applications such as Natural Language Processing (NLP), AI-integrated Electronic Health Records (EHR), Machine Learning (ML), Clinical Decision Support Systems (CDSS), and Generative AI-driven tools such as ChatGPT. Burnout was the most frequently addressed mental health issue, followed by stress and cognitive load. Clinical documentation emerged as the most frequently addressed workflow, followed by clinical decision-making and diagnostics. Literature indicated that AI was capable of streamlining workflows, reducing administrative burden, and improving job satisfaction among HCWs. However, challenges such as data integration, algorithmic bias, and increased oversight demands were noted as potential barriers to effective implementation.ConclusionAI holds significant potential to improve HCWs' mental health and well-being by addressing workflow inefficiencies and reducing administrative burden. While available evidence highlights its benefits in enhancing job satisfaction and mitigating burnout, challenges such as data standardisation and user trust must be addressed for successful adoption. Future research should focus on evaluating the long-term impacts of AI on HCWs' mental well-being and developing strategies to mitigate unintended consequences
A Comparison of Diet and Exercise During Pregnancy in Women With and Without Type 1 Diabetes Followed in the Environmental Determinants of Islet Autoimmunity (ENDIA) Study
No full textOBJECTIVE: To compare diet and physical activity during pregnancy in women with and without type 1 diabetes and assess against national dietary guidelines. RESEARCH DESIGN AND METHODS: Diet and physical activity were measured prospectively in 1,124 pregnancies using validated questionnaires. RESULTS: Diets exceeded recommended intake for fat, saturated fat, discretionary foods, sodium, vitamin C, calcium, and zinc and were below recommendations for carbohydrate, fruit, dairy, vegetables, grain foods, and lean meats and alternatives. Differences in dietary intake between women with and without type 1 diabetes were modest. Total, moderate, and vigorous physical activity decreased in the third trimester. Women with type 1 diabetes performed less vigorous intensity activity than women without type 1 diabetes. CONCLUSIONS: Most pregnant women with and without type 1 diabetes did not meet dietary guidelines. Physical activity patterns were also mostly similar in women with and without type 1 diabetes.Rebecca L. Thomson, Guinevere Martin, James D. Brown, Helena Oakey, Pat Ashwood, Megan A.S. Penno, Kelly J. McGorm, Rachel Battersby, Peter G. Colman, Maria E. Craig, Elizabeth A. Davis, Tony Huynh, Aveni Haynes, Timothy Spelman, Georgia Soldatos, Peter J. Vuillermin, John M. Wentworth, Sarah A.L. Price, Jennifer J. Couper, ENDIA Study Grou
Update on First-in-Human Experience of High-Energy ElectroPulse Pulsed Field Ablation
No full textBACKGROUND The ElectroPulse system is a novel pulsed field ablation (PFA) platform integrating mapping and ablation in a small-diameter catheter with irrigation and wire-free design. OBJECTIVE The purpose of this study was to present mid-term outcomes from 2 sequential first-in-human cohorts for pulmonary vein isolation and posterior wall isolation (PVI and PWI). METHODS The ElectroPulse trial enrolled 60 patients with symptomatic atrial fibrillation undergoing de novo ablation. Cohort 1 (n 5 30) followed the standard protocol, while cohort 2 (n 5 30) used a modified protocol. The primary end point was time to first atrial arrhythmia ≥30 seconds; secondary end points included efficacy and safety, with exploratory analyses of pulmonary vein reconnection and lesion durability. Outcomes were assessed through clinic visits, electrocardiograms, and 4-day Holter monitoring every 3 months. RESULTS Compared with patients in cohort 1, those in cohort 2 were older (P 5 .005), had larger left atrial volumes (P 5 .009), and higher CHA 2 DS 2 -VA scores (P 5 .002). The modified protocol reduced PFA applications and procedure time (P < .001), with 100% (n 5 60) acute PVI/PWI in both cohorts. At 6 months, 16% (n 5 5) of cohort 1 and 13% (n 5 4) of cohort 2 had atrial fibrillation recurrence (P 5 .834). Redo ablation was required in 16.6% (n 5 5) of cohort 1 but only in 3.3% (n 5 1) of cohort 2 (P 5 .19). Durable PVI was seen in 27% (n 5 3) of repeat procedures in cohort 1 vs 100% (n 5 3) in cohort 2. Complication rates were low and similar. CONCLUSION ElectroPulse PFA enables safe and effective PVI and PWI. The updated high-energy protocol improves efficiency by reducing applications and procedure duration while increasing durability without compromising safety or efficacy.Saikiran Kakarla, Mehrdad Emami, Alexis Puvrez, Glenn D. Young, Jonathan Ariyaratnam, Suraya Kamsani, Melissa E. Middeldorp, Martin K. Stiles, Bradley Wilsmore, Peter M. Kistler, Rajeev K. Pathak, Jonathan M. Kalman, Prashanthan Sander
The nuclear and mitochondrial genomes need to tango. How is their dance synchronized during development?
No full textFor quite some time, knowledge about mitochondria and the mitochondrial genome has been primarily limited to energy production. However, there is now increasing evidence that they have many important roles in cell function and that synergy between the nuclear and mitochondrial genomes is an essential prerequisite to developmental outcome. This review describes the mitochondrial genome and its contribution to o v er- all cellular genomic content; and discusses mitochondrial DNA (mtDNA) inheritance. mtDNA homoplasmy and heteroplasmy are defined and distinctions between pathogenic and non-pathogenic rearrangements are drawn; how they are transmitted; and their effects on oocyte quality and developmental outcomes. This is followed by analysis of mtDNA replication and changes in mtDNA copy number during development; why they need to happen; and how they influence developmental outcomes. Changes to nuclear DNA methylation events are then discussed in the context of changes to mtDNA replication throughout development. This leads to the concept of ‘genomic balance’, which defines how cells at any stage of development require adjustments to both genomes to ensure successful cellular function and development; and how this process can be perturbed by some of the more invasive assisted reproductive technologies designed to treat infertility and mtDNA disease.Justin C. St. Joh