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Simulation of X-ray projections on GPU: benchmarking gVirtualXray with clinically realistic phantoms
Get PDFThis study provides a quantitative comparison of images created using gVirtualXray (gVXR) to both Monte Carlo (MC) and real images of clinically realistic phantoms. gVirtualXray is an open-source framework that relies on the Beer-Lambert law to simulate X-ray images in realtime on a graphics processor unit (GPU) using triangular meshes. Images are generated with gVirtualXray and compared with a corresponding ground truth image of an anthropomorphic phantom: (i) an X-ray projection generated using a Monte Carlo simulation code, (ii) real digitally reconstructed radiographs (DRRs), (iii) computed tomography (CT) slices, and (iv) a real radiograph acquired with a clinical X-ray imaging system. When real images are involved, the simulations are used in an image registration framework so that the two images are aligned. The mean absolute percentage error (MAPE) between the images simulated with gVirtualXray and MC is 3.12%, the zero-mean normalised cross-correlation (ZNCC) is 99.96% and the structural similarity index (SSIM) is 0.99. The run-time is 10 days for MC and 23 ms with gVirtualXray. Images simulated using surface models segmented from a CT scan of the Lungman chest phantom were similar to (i) DRRs computed from the CT volume and (ii) an actual digital radiograph. CT slices reconstructed from images simulated with gVirtualXray were comparable to the corresponding slices of the original CT volume. When scattering can be ignored, accurate images that would take days using MC can be generated in milliseconds with gVirtualXray. This speed of execution enables the use of repetitive simulations with varying parameters, e.g. to generate training data for a deep-learning algorithm, and to minimise the objective function of an optimisation problem in image registration. The use of surface models enables the combination of X-ray simulation with real-time soft-tissue deformation and character animation, which can be deployed in virtual reality applications. [Abstract copyright: Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.
The ripple effect of sexual trauma: A qualitative exploration of direct effects on women survivors’ partner relationships and indirect effects on clinical psychologists
Get PDFOver 50 years of behavioural evidence on the magnetic sense in animals: what has been learnt and how?
Get PDFMagnetoreception is a key element in the sensory repertoire of many organisms, and it has been shown to play a particular role in animal navigation. While the first data to demonstrate a magnetic compass in songbirds through behavioural measures were presented decades ago, studies of behaviour are still the main source of information in learning about the magnetic senses. The behavioural evidence is, however, scattered with sometimes contradictory results. Partly, this is a consequence of a wide spectrum of methods used across multiple research groups studying different model organisms. This has limited the ability of researchers to pin down exactly how and why animals use the Earth’s magnetic field. Here, we lay out how a range of methods for testing behaviour spanning from field observations to laboratory manipulations can be used to test for a magnetic sense in animals. To this end, we discuss the principal limitations of behavioural testing in telling us how animals sense the magnetic field, and we argue that behaviour must go hand in hand with other fields to advance our understanding of the magnetic sense
Consistency and Variation in the Kelp Microbiota: Patterns of Bacterial Community Structure Across Spatial Scales
Get PDFKelp species are distributed along ~ 25% of the world’s coastlines and the forests they form represent some of the world’s most productive and diverse ecosystems. Like other marine habitat–formers, the associated microbial community is fundamental for host and, in turn, wider ecosystem functioning. Given there are thousands of bacteria-host associations, determining which relationships are important remains a major challenge. We characterised the associated bacteria of two habitat-forming kelp species, Laminaria hyperborea and Saccharina latissima, from eight sites across a range of spatial scales (10 s of metres to 100 s of km) in the northeast Atlantic. We found no difference in diversity or community structure between the two kelps, but there was evidence of regional structuring (across 100 s km) and considerable variation between individuals (10 s of metres). Within sites, individuals shared few amplicon sequence variants (ASVs) and supported a very small proportion of diversity found across the wider study area. However, consistent characteristics between individuals were observed with individual host communities containing a small conserved “core” (8–11 ASVs comprising 25 and 32% of sample abundances for L. hyperborea and S. latissima, respectively). At a coarser taxonomic resolution, communities were dominated by four classes (Planctomycetes, Gammaproteobacteria, Alphaproteobacteria and Bacteroidia) that made up ~ 84% of sample abundances. Remaining taxa (47 classes) made up very little contribution to overall abundance but the majority of taxonomic diversity. Overall, our study demonstrates the consistent features of kelp bacterial communities across large spatial scales and environmental gradients and provides an ecologically meaningful baseline to track environmental change
Replika in the Metaverse: the moral problem with empathy in ‘It from Bit’
Get PDFThis paper assesses claims of computational empathy in relation to existing social open-ended chatbots and intention that these chatbots will feature in emergent mixed reality contexts, recently given prominence due to interest in the Metaverse. Against the background of increasing loneliness within society and use of chatbots as a potential remedy for this, the paper considers two leading current social chatbots, Replika and Microsoft's Xiaoice, their technical underpinnings, empathetic claims and properties that have scope to scale into the Metaverse (if it coheres). Finding scope for human benefit from social chatbots, the paper highlights problematic reliance on self-disclosure to sustain the existence of chatbots. The paper progresses to situate Microsoft's empathetic computing framework in relation to philosophical ideas that inform Metaverse speculation and construction, including Wheeler's 'It from Bit' thesis that all aspects of existence may be computed, Chalmers' philosophical championing that virtual realities are genuine realities, Bostrom's proposal and provocation that we might already be living in a simulation, and longtermist belief that future complex simulations need to be protected from decisions made today. Given claims for current and nascent social chatbots, belief in bit-based possible and projected futures, and industrial buy-in to these philosophies, this paper answers whether computational empathy is real or not. The paper finds when diverse accounts of empathy are accounted for, whilst something is irrevocably lost in an 'It from Bit' account of empathy, the missing components are not accuracy or even human commonality of experience, but the moral dimension of empathy. </p
Feminising care pathways: Mixed-methods study of reproductive options, decision making, pregnancy, post-natal care and parenting amongst women with kidney disease.
Get PDFAimsTo identify the needs, experiences and preferences of women with kidney disease in relation to their reproductive health to inform development of shared decision-making interventions.DesignUK-wide mixed-methods convergent design (Sep 20–Aug 21).MethodsOnline questionnaire (n = 431) with validated components. Purposively sampled semi-structured interviews (n = 30). Patient and public input throughout.FindingsKidney disease was associated with defeminization, negatively affecting current (sexual) relationships and perceptions of future life goals. There was little evidence that shared decision making was taking place. Unplanned pregnancies were common, sometimes influenced by poor care and support and complicated systems. Reasons for (not) wanting children varied. Complicated pregnancies and miscarriages were common. Women often felt that it was more important to be a “good mother” than to address their health needs, which were often unmet and unrecognized. Impacts of pregnancy on disease and options for alternates to pregnancy were not well understood.ConclusionThe needs and reproductive priorities of women are frequently overshadowed by their kidney disease. High-quality shared decision-making interventions need to be embedded as routine in a feminized care pathway that includes reproductive health. Research is needed in parallel to examine the effectiveness of interventions and address inequalities
Hypoxia-induced endothelial dysfunction: Could targeting oxidative stress provide protection?
Get PDFResolving land tenure security is essential to deliver forest restoration
Get PDFTropical countries are making ambitious commitments to Forest Landscape Restoration with the aim of locking up carbon, conserving biodiversity and benefiting local livelihoods. However, global and national analyses of restoration potential frequently ignore socio-legal complexities which impact both the effectiveness and equitability of restoration. We show that areas with the highest restoration potential are disproportionately found in countries with weak rule of law and frequently in those with substantial areas of unrecognised land tenure. Focussing on Madagascar, at least 67% of the areas with highest restoration potential must be on untitled land, where tenure is often unclear or contested, and we show how unresolved tenure issues are one of the most important limitations on forest restoration. This is likely to be a bigger problem than currently recognized and without important efforts to resolve local tenure issues, opportunities to equitably scale up forest restoration globally are likely to be significantly over-estimated
"Talk and Chalk": an emotion regulation intervention for anger after acquired brain injury
Get PDFUncontrollable anger is a debilitating consequence of acquired brain injury (ABI). This proof-of-concept study investigated the preliminary efficacy of an emotion regulation intervention for managing post-ABI anger. A secondary objective was to determine which participant characteristics were related to intervention gains. With a pre-post intervention design and three-month follow-up, there were five individually administered meetings on Zoom, over a four-month period. 24 adults who had sustained an ABI were enrolled. Participants were mostly males, from 24 to 85 years old. A series of one-way repeated-measures ANOVAs were conducted to determine the intervention’s efficacy, and Spearman’s rho bivariate correlations for the association between participant characteristics and intervention gains. Significant differences were observed in external anger from baseline to post-treatment; there were no further changes from post-treatment to follow-up. Of the participant characteristics, only readiness to change and anxiety were correlated. The proposed intervention presents a brief, feasible, and preliminary efficacious alternative for regulating post-ABI anger. Intervention gains are associated with readiness to change and anxiety, which has important implications for clinical delivery