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Modeling ice cliff stability using a new Mohr-Coulomb-based phase field fracture model
Get PDFIceberg calving at glacier termini results in mass loss from ice sheets, but the associated fracture mechanics is often poorly represented using simplistic (empirical or elementary mechanics-based) failure criteria. Here, we propose an advanced Mohr-Coulomb failure criterion that drives cracking based on the visco-elastic stress state in ice. This criterion is implemented in a phase field fracture framework, and finite element simulations are conducted to determine the critical conditions that can trigger ice cliff collapse. Results demonstrate that fast-moving glaciers with negligible basal friction are prone to tensile failure causing crevasse propagation far away from the ice front; whilst slow-moving glaciers with significant basal friction are likely to exhibit shear failure near the ice front. Results also indicate that seawater pressure plays a major role in modulating cliff failure. For land terminating glaciers, full thickness cliff failure is observed if the glacier exceeds a critical height, dependent on cohesive strength τc (H ≈ 120 m for τc = 0.5 MPa). For marineterminating glaciers, ice cliff failure occurs if a critical glacier free-board (H - hw) is exceeded, with ice slumping only observed above the ocean-water height; for τc = 0.5 MPa, the model-predicted critical free-board is H - hw ≈ 215 m, which is in good agreement with field observations. While the critical free-board height is larger than that predicted by some previous models, we cannot conclude that marine ice cliff instability is less likely because we do not include other failure processes such as hydrofracture of basal crevasses and plastic necking
Future Circular Collider Feasibility Study Report: Volume 3 Civil Engineering, Implementation and Sustainability
Get PDFVolume 3 of the FCC Feasibility Report presents studies related to civil engineering, the development of a project implementation scenario, and environmental and sustainability aspects. The report details the iterative improvements made to the civil engineering concepts since 2018, taking into account subsurface conditions, accelerator and experiment requirements, and territorial considerations. It outlines a technically feasible and economically viable civil engineering configuration that serves as the baseline for detailed subsurface investigations, construction design, cost estimation, and project implementation planning. Additionally, the report highlights ongoing subsurface investigations in key areas to support the development of an improved 3D subsurface model of the region. The report describes the development of the project scenario based on the ‘avoid-reduce-compensate’ iterative optimisation approach. The reference scenario balances optimal physics performance with territorial compatibility, implementation risks, and costs. Environmental field investigations covering almost 600 hectares of terrain—including numerous urban, economic, social, and technical aspects—confirmed the project’s technical feasibility and contributed to the preparation of essential input documents for the formal project authorisation phase. The summary also highlights the initiation of public dialogue as part of the authorisation process. The results of a comprehensive socio-economic impact assessment, which included significant environmental effects, are presented. Even under the most conservative and stringent conditions, a positive benefit-cost ratio for the FCC-ee is obtained. Finally, the report provides a summary of the studies conducted to document the current state of the environment
VolGAN: a generative model for arbitrage-free implied volatility surfaces
Get PDFWe introduce VolGAN, a generative model for arbitrage-free implied volatility surfaces. The model is trained on time series of implied volatility surfaces and underlying prices and is capable of generating realistic scenarios for joint dynamics of the implied volatility surface and the underlying asset. We illustrate the performance of the model by training it on SPX implied volatility time series and show that it is able to learn the covariance structure of the co-movements in implied volatilities and generate realistic dynamics for the (VIX) volatility index. In particular, the generative model is capable of simulating scenarios with non-Gaussian distributions of increments for state variables as well as time-varying correlations. Finally, we illustrate the use of VolGAN to construct data-driven hedging strategies for option portfolios, and show that these strategies can outperform Black–Scholes delta and delta-vega hedging
Exploring the use of machine learning to assess the respiratory function of preterm infants
Get PDFBackground: Preterm birth is associated with a number of pathologies that affect respiratory function. The identification of reduced lung function could aid with clinical diagnosis, earlier intervention and improved clinical outcomes for preterm infants. We explored the use of inter-breath intervals to predict the age at which healthy preterm infants’ lungs are functioning. This can provide the groundwork to build a clinical tool that can assess preterm lung function in clinical practice. Methods: Inter-breath intervals, measured through vital signs monitoring, were longitudinally recorded in healthy preterm infants with a post-menstrual age (PMA) < 37 weeks. Dataset 1, consisting of data from 32 infants, was analysed to compute 49 respiratory and statistical features. The relationship of these features with PMA was assessed through linear regression models. All features were used as inputs to train selected machine learning models to produce a predicted PMA. Mean Absolute Error (MAE) values were used to assess model accuracy. Machine learning models with higher levels of accuracy were selected for the next stage of analysis. Inter-breath interval data from dataset 2 were analysed, consisting of 66 infants across 161 recordings. 50 features were extracted and used as inputs to train the selected models to output a predicted PMA. The most accurate model was used for further analysis to assess whether performance is affected by sex (paired t-test), ventilation method (ANOVA), and post-natal age (linear regression). Results: 12 features from dataset 1 and 31 features from dataset 2 had a significant relationship with PMA (p < 0.05). The most accurate model was the bagged trees model trained on all 50 features, with a MAE of 1.30 weeks. Sex (p = 0.17), ventilation method (p = 0.79) and post-natal age (p = 0.99) did not affect model performance. Conclusion: Inter-breath interval data offers novel directions for assessing the respiratory function of preterm infants
Investigating the current implementation barriers and the potential social and ecological effects of a CITES reverse listing on the international exotic pet trade
No full textThe trade in exotic pets is a significant contributor to the unsustainable and sustainable trade of wildlife. The Convention on the International Trade in Endangered Species of Wild Fauna and Flora (CITES) aims to regulate sustainable wildlife trade.A reverse listing (RL) has previously been proposed, which bans trade of all species until trade is proven to be sustainable, when they are added to a positive list permitting trade. Since the 1980s, this concept's effectiveness has been debated.We identified zoonoses, invasive alien species (IAS), welfare, livelihoods, sustainable harvest and legal trade as six important themes in exotic pet trade literature. We used an adapted investigate, discuss, explain, aggregate (IDEA) protocol to collect expert estimates on the effects of a CITES RL on the identified socioecological themes and determined areas of uncertainty to guide future research.We find that experts differ in estimates on zoonoses, IAS, livelihoods, welfare, sustainable harvest and legal trade. Responses indicate that how RL would be implemented and what it would include generated the most uncertainty in effect estimates. Experts were particularly concerned with the effect of RL on the amount of legal trade and sustainable harvest. There was concern that the frequency of legal trade in exotic pets would decrease as species would be illegally trafficked to circumnavigate new restrictions causing a decrease in harvest sustainability. This shift was predicted to negatively affect livelihoods for those dependent on the legal trade of exotic pets.The results show that greater clarity on what the aims of a RL are, what would be included in the listing criteria and what would be expected by the signatories would improve the quality of research on RL. This would support more evidence-based decision-making for the future trajectory of CITES and the regulation of sustainable trade
Multiomic analyses direct hypotheses for Creutzfeldt-Jakob disease risk genes
Get PDFPrions are assemblies of misfolded prion protein that cause several fatal and transmissible neurodegenerative diseases, with the most common phenotype in humans being sporadic Creutzfeldt-Jakob disease (sCJD). Aside from variation of the prion protein itself, molecular risk factors are not well understood. Prion and prion-like mechanisms are thought to underpin common neurodegenerative disorders meaning that the elucidation of mechanisms could have broad relevance. Herein we sought to further develop our understanding of the factors that confer risk of sCJD using a systematic gene prioritization and functional interpretation pipeline based on multiomic integrative analyses.
We integrated the published sCJD genome-wide association study summary statistics with publicly available bulk brain and brain cell type gene and protein expression datasets. We performed multiple transcriptome and proteome-wide association studies and Bayesian genetic colocalization analyses between sCJD risk association signals and multiple brain molecular quantitative trait loci signals. We then applied our systematic gene prioritization pipeline to the obtained results and nominated prioritized sCJD risk genes with risk-associated molecular mechanisms in a transcriptome and proteome-wide manner.
Genetic upregulation of both gene and protein expression of syntaxin-6 (STX6) in the brain was associated with sCJD risk in multiple datasets, with a risk-associated gene expression regulation specific to oligodendrocytes. Similarly, increased gene and protein expression of protein disulfide isomerase family A member 4 (PDIA4), involved in the unfolded protein response, was linked to increased disease risk, particularly in excitatory neurons. Protein expression of mesencephalic astrocyte derived neurotrophic factor (MANF), involved in protection against endoplasmic reticulum stress and sulfatide binding (linking to the enzyme in the final step of sulfatide synthesis, encoded by sCJD risk gene GAL3ST1), was identified as protective against sCJD. In total 32 genes were prioritized into two tiers based on the level of evidence and confidence for further studies.
This study provides insights into the genetically-associated molecular mechanisms underlying sCJD susceptibility and prioritizes several specific hypotheses for exploration beyond the prion protein itself, as well as beyond the previously highlighted sCJD risk loci, through the newly prioritized sCJD risk genes and mechanisms. These findings highlight the importance of glial cells, sulfatides and the excitatory neuron unfolded protein response in sCJD pathogenesis
Non‐Invasive Monitoring of Hazel Dormouse ( Muscardinus avellanarius ): First Insights on Genetic Data Quality From the First Pilot Study
Get PDFGenetic non‐invasive sampling (gNIS) methods, which enable DNA extraction from naturally shed materials, offer a powerful, low‐impact tool for studying elusive species, minimising disturbance and ethical concerns. However, such approaches require careful assessment of sample quality and data accuracy to ensure reliable genetic results. The hazel dormouse ( Muscardinus avellanarius ) is an arboreal rodent that plays a crucial role in ecosystems. Despite conservation concerns arising from its low population densities, which are closely linked to habitat quality, it remains poorly understood due to monitoring challenges. This pilot study, conducted in the high Agri Valley (Basilicata, Italy), evaluates a non‐invasive genetic sampling protocol for the hazel dormouse using hair‐tubes. We investigated the genotyping efficiency, the reliability and informativeness of selected microsatellite markers and the impact of hair sample quantity and trap placement duration on genotyping success and error rates. We used 126 hair tube traps at 14 sampling sites, obtaining reliable genotypes for 14 individuals out of 32 hair samples collected, with a genotyping efficiency significantly affected by both the number of hairs collected and the collecting time interval. The microsatellite marker panel showed a high number of alleles and a low probability of identity, proving to be informative for population monitoring. The results underscore the potential of this non‐invasive approach for monitoring elusive and conservation‐priority species while highlighting the need to minimise field collection time and optimise trap design to improve DNA quality and genotyping reliability
Nitrogen deposition reveals global patterns in plant and animal stoichiometry
Get PDFThe elemental content of organisms links cellular biochemistry to ecological processes, from physiology to nutrient dynamics. While plant stoichiometry is thought to vary with climate and nutrient availability across latitudes, the consistency of these patterns across trophic groups and realms remains unclear. Using the StoichLife database, which includes nitrogen and phosphorus content data for 5443 species across 1390 sites, we examine how solar energy (temperature, radiation) and nutrients (nitrogen and phosphorus) influence stoichiometric variation. We find that plant stoichiometry in terrestrial and freshwater ecosystems is more strongly associated with environmental gradients, particularly nitrogen deposition, than animal stoichiometry. Contrary to expectations, temperature, radiation, and labile P show limited global effects. Latitudinal patterns in stoichiometry are more closely associated with species turnover rather than intraspecific variation. Given the strong links between stoichiometry and organismal performance, these findings underscore the need to predict the ecological consequences of anthropogenic disruption to global biogeochemical cycles
Platform trials to assess therapeutics in patients hospitalized with influenza
Get PDFEvidence-based effective treatments for hospitalized patients with influenza have yet to be identified. Traditional randomized controlled trials have struggled to provide definitive guidance due in part to small sample sizes and logistical challenges. Adaptive platform trials, such as REMAP-CAP (Randomised Embedded Multifactorial Adaptive Platform for Community-Acquired Pneumonia) and RECOVERY (Randomised Evaluation of COVID-19 Therapy), offer a transformative approach to evaluating influenza therapeutics. REMAP-CAP and RECOVERY utilize flexible, efficient designs that enable the simultaneous assessment of multiple interventions, adaptation to emerging data, and large-scale recruitment. Both platforms are currently evaluating antiviral and immunomodulatory therapies for severe influenza, building on their success in identifying effective treatments for COVID-19. Establishing global platform trials for influenza will facilitate the generation of high-quality evidence to guide seasonal influenza treatment and enhance pandemic preparedness. A coordinated international effort to sustain platform trials beyond pandemic periods is essential for improving clinical outcomes, optimizing resource utilization, and ensuring readiness for future pandemics
Infant Botulism: A Case Study in Integrated Clinical and Public Health Response
Get PDFEarly recognition of constipation, feeding difficulty, and descending weakness in infants is vital for prompt diagnosis of infant botulism. Bedside nerve studies support early treatment. Rapid public health notification and coordinated access to specific therapies, including timely use of BAT and BIG‐IV, are essential to optimize outcomes and safety