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The Holocene evolution of a sinkhole on the Southeast Red Sea Shelf:From saline palaeolake to stratified marine setting
No full textThe submerged coastal landscapes of the southern Red Sea preserve key archives of postglacial environmental change, shaped by sea-level rise and shifting hydroclimatic regimes. On the southeast shelf, the Farasan Deep—a deep, morphologically isolated sinkhole—records a rare transition from a saline palaeolake to a stratified marine setting. We present a new multiproxy record from sediment core FA24, integrating lipid biomarkers (branched and isoprenoid glycerol dialkyl glycerol tetraethers [GDGTs]), XRF-core scanning, LOI, sedimentology, and micropalaeontology to reconstruct water-column structure, redox dynamics, and microbial and faunal shifts over the past 11.8 kyr. Results reveal three distinct phases. Phase I (11.8–8.7 ka) reflects hydrographic isolation, strong stratification, and sustained bottom-water anoxia. Laminated organic-rich sediments, diatom mats, low foraminiferal counts, and biomarker evidence indicate persistent oxygen depletion and a distinct microbial ecology. Phase II (8.7–6.7 ka) captures transitional dynamics, marked by episodic marine incursions, fluctuating redox conditions, rising GDGT inputs, and sporadic foraminiferal reappearances. Phase III (post-6.7 ka) signals full marine reconnection with stable stratification, persistent bottom-water anoxia, increased microbial lipid production, and benthic foraminiferal assemblages dominated by infaunal taxa. The Farasan Deep record sheds light on the timing and feedbacks of postglacial marine reconnection in marginal basins. Beyond its regional context, it provides a globally relevant analogue for redox-sensitive carbon cycling, stratification feedbacks, and GDGT proxy behavior in semi-enclosed systems. These findings further underscore the geoarchaeological significance of submerged landscapes and support improved palaeoclimate reconstructions in hydroclimatically sensitive marine settings
Age and QMP exposure affect the nutritional preferences of caged Apis mellifera worker honeybees
Get PDFEusocial insect queens often use pheromones to prevent reproduction in the worker caste, enforcing the reproductive constraint that is central to eusociality. In A. mellifera honeybees, the queen emits several pheromones that affect worker reproduction, the most important being QMP. Although the effects of QMP have been studied in some detail, the mechanisms by which it brings about reproductive constraint in workers are still unclear. Remarkably, QMP is also able to repress reproduction in other insects, including the fruit fly Drosophila melanogaster, in which QMP has been shown to induce a starvation-like response. Here we use caged newly eclosed workers with an ad libitum choice of protein and sugar food sources to investigate whether QMP alters dietary intake in the honeybee. We show that initially, irrespective of QMP exposure, workers only consume protein, before shifting to carbohydrate after 4 days. We also show that QMP exposure results in an increased preference and intake of carbohydrates in worker bees, raising the possibility that QMP also induces a starvation-like response in honeybees
Assessment of fluid ingress into the graft-host interface of osteochondral grafts and synthetic scaffolds under cyclic axial loading in a tibio-femoral model
Get PDFThis study developed an in vitro method to evaluate fluid ingress into the graft-host interface of osteochondral grafts and mimetic constructs and the risk of graft subsidence, using porcine and ovine tibio-femoral models, to investigate mechanisms associated with cyst development. Distal femurs were implanted with two osteochondral grafts or mimetic constructs. One was implanted axially with the loading direction at the point of initial contact of the femur and tibia (“loaded graft”); another on an unloaded portion of the opposite condyle (“unloaded graft”). During testing under a uniaxial cyclic loading regime, the specimens were housed in a contrast medium. Micro-CT scans taken before and after testing allowed the movement of the contrast fluid to be visualized. Fluid ingress was quantified by comparing the greyscale distribution across line profiles between the μCT scans. Ingress was calculated at six sites of interest: two at each graft site (“graft-host interface”, “graft centre”), one through “loaded host bone”, and one through “unloaded host bone”. Graft presence and loading were key factors to promote fluid ingress (p = 0.001). Fluid ingress at loaded graft-host interfaces relative to the unloaded host bone of porcine-in-porcine was 2.4 ± 8.9 mm, porcine-in-ovine was 9.9 ± 3.1 mm, and mimetic constructs-inporcine was 3.6 ± 3.8 mm. A mismatch in material properties between the graft and host bone promoted ingress, driven by host bone quality. Subchondral bone damage and fluid pooling below grafts was detectable from μCT images. Results indicate host bone quality should be considered when assessing a patient’s suitability for surgery
A Class of Fluid-Structure Interaction Problems with Analytical Solutions for the Validation of Numerical Methods
Get PDFAnalytical solutions to Fluid-Structure Interaction (FSI) problems are almost absent in the literature. However, they are crucial for validation and convergence analysis of numerical methods, as well as for providing insight into the complex coupling dynamics between fluids and solids. In this paper, we derive two analytical and one semi-analytical solutions for three FSI problems, spanning a class of solutions by varying their geometrical and physical parameters. All solutions exhibit complex nonlinear behaviours, which we compare with numerical simulations using a monolithic method. These three FSI problems are described in the cylindrical coordinates, drawing inspiration from Couette flow, with two of them featuring a moving fluid-solid interface and the third incorporating a nonlinear constitutive solid model. To the best of our knowledge, for the first time, we present FSI problems with analytical solutions that include a moving interface
Multi-perspective machine learning MPML: A high-performance and interpretable ensemble method for heart disease prediction
Get PDFMachine Learning (ML) has demonstrated strong predictive capabilities in healthcare, often surpassing human performance in pattern recognition and decision-making. However, many high-performing models lack interpretability, which is critical in clinical settings where understanding and trusting predictions is essential. To achieve our objective, we proposed a Multi-Perspective machine learning framework (MPML) that combines established base classifiers with structured perspective-based design and interpretability pipeline. MPML organises features into meaningful subsets, or perspectives, enabling both global and instance-level interpretability. Unlike traditional ensemble methods such as Bagging, Boosting, and Random Forest, MPML delivers significantly higher-quality predictions across all evaluation metrics while maintaining a transparent structure. Applied to a heart disease dataset, MPML not only improves predictive accuracy but also provides detailed, accessible explanations for individual patient outcomes, advancing the potential for practical and ethical deployment of ML in healthcare
Methodological assumptions and limitations of life expectancy estimates for minoritised ethnic groups in the UK:implications for validity, practice, and policy
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Fibre-optic sensor design and strain-response analysis to wall pressure fluctuations in turbulent partially-filled pipe flows
No full textMany studies exist analysing dynamics of pressure-driven flows, yet the number of studies quantifying hydrodynamic relations in partially-filled gravity-driven pipe flows remains limited. This work presents strain data for two uniform, steady flow regimes from a novel streamwise, flush-mounted fibre-optic sensor embedded in the interior wall of a partially-filled pipe. The sensor responds to turbulence-induced pressure fluctuations at the wall, transducing them into measurable strain via a custom plate-gel structure. This sensor represents the first of its kind for non-invasive response to wall pressure fluctuations in partially-filled pipes. Cross-correlation analysis recovered bulk flow velocity estimates within 5% of the true velocity. A Metropolis–Hastings-based automated filtering process identified the frequency range retaining bulk flow properties while removing noisy measurements, further refining velocity estimates. The identified streamwise correlation pattern agreed with experimentally observed wall pressure correlations. Results suggest streamwise correlations decay at a rate proportional to the hydraulic radius in each regime, with only a 7% discrepancy between regimes. Furthermore, spectral analysis indicates the sensor’s sensitivity to coherent large-scale turbulent structures from wall data alone, a capability not previously demonstrated experimentally, suggesting potential for monitoring flow structures beyond bulk conditions. Out-of-water tests produced uninformative results, confirming that in-flow placement captures genuine flow dynamics. These findings demonstrate a novel sensing approach to monitoring partially-filled pipe flows, providing both bulk property estimation and insights into multi-scale flow structures from data collection at the wall, making way for a new form of sensor to be deployed for monitoring these flows in varying industrial contexts
Strategies to support safe wandering in care homes for older adults – what works, for whom, and in which circumstances?: A realist synthesis
No full textObjectives
Wandering is a common behaviour among people with dementia living in care homes, driven by various factors such as enjoyment, a sense of purpose, lifelong habits, and social interaction. These elements can bring both physical and mental benefits, highlighting the need for strategies that enable safe wandering while respecting individual autonomy. This realist synthesis aimed to explore these strategies and the conditions under which they lead to successful outcomes.
Methods
This realist synthesis involved scoping the literature to develop initial theoretical explanations for how different strategies could support safe wandering. From this literature, we developed context-mechanism-outcome configurations, which we combined into initial programme theories. Systematic searches were then used to test and refine these programme theories. Studies were prioritised for inclusion based on criteria of relevance and richness. We extracted data pertinent to the initial programme theories and documented relevance, richness, and rigour. We synthesised data into five refined programme theories. At each stage of the process, we collaborated with stakeholders to develop and validate the strategies.
Results
The review included 79 evidence sources, leading to five refined programme theories. 1) Personalised Care: Emphasising the importance of staff practicing person-centred care by understanding residents, their reasons for wandering, and their life histories. 2) Monitoring: Effective monitoring requires good visual access or technological solutions that enable staff to observe residents, and detect when residents need support to walk while also enabling resident freedom and independence. 3) Navigation: Navigation is facilitated by dementia-friendly design features and environmental cues, which help minimise the challenges residents face due to diminished orientation and wayfinding abilities. 4) Managing access: Involving balancing residents' safety and autonomy. Strategies may include restricting access to unsafe areas by locking doors or using technology and camouflage, while ensuring access to safe spaces. 5) Hydration and nutrition: Hydration and nutrition (e.g., suitable snacks) is provided to prevent weight loss for residents who wander and may not stay seated during meals. These theories provide insight into supporting safe wandering, leading to improved wellbeing for both residents and staff, enhanced safety and autonomy for residents, and reduced staff anxiety.
Discussion
Strategies that create a supportive environment, provide physical assistance, and support hydration and nutrition enabled residents to wander safely. Identified strategies improved wellbeing for both residents and staff. However, the same strategies also led to ethical concerns around digital monitoring, deception, and access restrictions
Men’s preferences for exiting abdominal aortic aneurysm surveillance: a deliberative engagement session study
Get PDFThe national screening programme guidance for Abdominal Aortic Aneurysm (AAA) in England states that men with small AAAs will exit surveillance after 15 years. This study explored the informed preferences of men for AAA surveillance. A Deliberative Engagement Session was conducted in two workshops comprising 30 men in AAA surveillance and six of their family members. The workshops consisted of measurement of men’s knowledge and preferences pre- and post-deliberation, presentations by experts, and deliberation by men and their family members, in terms of knowledge sharing and discussion. Before deliberation, only two of the 30 men in the session were aware of the existence of an exit strategy from AAA surveillance, and their knowledge levels about AAA were poor. Post-deliberation, knowledge levels increased from a median score of 6 (IQR 4 to 7) to a median score of 8 (IQR 8 to 9) correct answers to 11 multiple-choice questions about AAA and AAA screening (p < 0.001). Men in the session identified rate of growth of AAA, size of AAA, health issues that may make surgery risky, and the views of healthcare professionals as important factors to consider in any exit strategy. Most men in the session preferred a strategy whereby they were not discharged from surveillance but had longer intervals between scans (two yearly rather than yearly). Discussion revealed the importance to men and family members of the reassurance surveillance offered to them. In terms of how decisions should be made regarding exit, men in this session wanted to have estimates of the risks of different options, to discuss exit with a Nurse Specialist, and that the patient should decide. Based on informed preferences, men in this Deliberative Engagement Session preferred longer intervals between scans rather than exiting surveillance because of the reassurance offered by surveillance
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