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International survey showed that supraglottic airway devices were not often used for surfactant administration
Get PDFAim: Surfactant can be administered by an endotracheal tube or by a catheter through the vocal cords, but both techniques need laryngoscopy skills and can be associated with complications. Supraglottic airway devices have also been used for surfactant administration, and we conducted an international survey to understand how much this is done in current practice.
Methods: This online survey was conducted from September 2023 to June 2024. Questions broadly addressed unit structure, practices around surfactant, and the role of supraglottic airway device in their unit.
Results: There were a total of 75 responses, 73% from the United Kingdom. Most of the responses were from intensive care (55%). Fifty-three units reported the use of a supraglottic airway device only in cases of unsuccessful intubation. Only 12 units report the use of a supraglottic airway device for surfactant administration. Twenty-two units reported that they are likely to use this device in the near future, and five of the special care units reported that this technique would be useful for units with limited intubation skills.
Conclusion: There is limited uptake of using supraglottic airway device for surfactant administration. Lack of training, guidelines, and evidence are the most common reasons limiting this practice
Sanctions and currencies in global credit
Get PDFThis paper studies the effect of financial sanctions on the dominance of the US dollar in global credit markets. In the aftermath of the invasion of Crimea in 2014, sanctions imposed by both the US and the EU restricted the provision of financial services to Russian firms. We document how, between 2014 and 2021, the share of global cross-border credit to Russia denominated in US dollars declined from 65% to 25%, while the share denominated in euros rose from 20% to 45%. Relying on confidential bank-level data covering the universe of global banks located in the UK, we show that this shift was driven by banks previously lending to Russia in US dollars, and that banks shifted to euro lending to Russia regardless of whether their ultimate owner was based in a sanctioning jurisdiction or not. We argue that this euroisation relates to an increase in the relative “settlement risk” of US dollar claims, in the context of US extra-territorial sanctions targeting the dollar payment system. We rationalise our findings in a three-country model with financial intermediaries, where sanctions are introduced as both jurisdiction and currency-circuit specific frictions
Confidence and insight into working memories are shaped by attention and recent performance
Get PDFWorking memory is capacity limited, and our ability to access information from working memory is variable, but selective attention to working memory contents can improve performance. People are able to make introspective judgments regarding the quality of their memories, and these judgments are linked to objective memory performance. However, it remains unknown whether benefits of internally directed attention on memory performance occur alongside commensurate changes in introspective judgments. Across two experiments, we used retrospective cues (retrocues) during working-memory maintenance to direct attention to items in memory. We then examined their consequence on introspective judgments. In the second experiment, we provided trial-wise feedback on performance. We found that selective attention improved confidence judgments and not just performance of the probed item. We were also able to judge participants' genuine insight into working-memory contents through the correlation between confidence judgments and memory quality. Neurophysiologically, alpha desynchronization correlated first with memory error and then confidence during retrocueing, suggesting a sequential process of attentional enhancement of memory contents and introspective insight. Furthermore, we showed that participants can use feedback on the accuracy of confidence judgments to update their beliefs across time, according to performance. Our results emphasize flexibility in working memory by showing we can selectively modulate our confidence about its contents based on internally directed attention or objective feedback
Unravelling giant molecular clouds
Get PDFGiant molecular clouds (GMCs) provide the fuel for star formation and bear various feedbacks. Thus, they are key to our understanding of galaxy evolution and the baryon cycle. In this thesis, I study the cold molecular gas content in the nearby universe, including three megamaser-host galaxies, one early-type galaxy, and the central molecular zone (CMZ) of the Milky Way (MW). The spatial scales probed by the analyses range from kpc-scale gas discs (i.e. the environment GMCs reside in) to sub-pc clumps within GMCs.
I start with analysing the distribution and kinematics of the molecular gas of three megamaser galaxies: NGC 1194, NGC 3393, and NGC 5765B. I present Atacama Large Millimeter/sub-millimeter Array (ALMA) 12CO(2-1) observations with resolutions of about 100 pc. Every galaxy has an extended rotating molecular gas disc but all also have non-axisymmetric features. I explore the tentative correlation between the existence of megamasers and these features in the gas discs. I also examine the potential for using 12CO(2-1) as a dynamical tracer in these galaxies to measure the supermassive blackhole masses.
Next, I investigate resolved GMCs of the lenticular galaxy NGC 1387, exploiting high-resolution (14 pc) 12CO(2-1) observations from ALMA. I analysed the fundamental properties of 1285 individual GMCs. Unusually for an ETG, the GMCs of NGC 1387 follow scaling relations very similar to those of the MW disc, and most are virialised. A subset of GMCs have their angular momenta aligned with the large-scale galactic rotation.
Finally, in the MW CMZ, I study the gas-structure dendrogram across a large dynamical range (1–100 pc), primarily with ALMA HNCO(4-3) observations at 0.7 pc resolution. I discuss the dynamical state of the gas structures and identify galactic shear and magnetic fields as potential physical drivers of their morphologies.
Overall, this thesis has studied cold molecular gas (clouds) in special systems (megamaser hosts, the ETG, and the MW centre) with unprecedented physical resolutions. It enriches our understanding of molecular gas properties in the context of galaxy evolution
Seroepidemiology and mathematical modelling of non-polio enteroviruses
Get PDFEnteroviruses are spread fecal–orally or via respiratory transmission and cause a wide range of diseases. They generally cause mild and self-limited illness but have emerged to cause outbreaks with more severe disease manifestations than previously known. The principal public health needs for enterovirus surveillance include outbreak detection, response and monitoring of enteroviruses associated with severe disease. However, the burden of enterovirus infections is not adequately described due to inadequate systemic surveillance. Here, serum neutralizing antibodies to EV-D68, EV-A71, CVA6 and EV-D111 were measured in samples collected in the UK and four African countries to estimate population-level exposure.
Overall, the serology data showed high antibody levels and seroprevalence that reached 100% in adults indicating extensive exposure and ubiquitous virus circulation. Clinical detection of enteroviruses in the UK showed biennial and annual occurrence of EV-A71 and CVA6, respectively. CVA6 detections were marked by an increasing trend from 2006 to 2017. Model fitting of the seroprevalence data showed possible existence of age-specific transmission or relative risk of infection. The increase in virus detection or clinical occurrence without parallel increase in FOI could be attributed to a change in virus characteristics or pathogenicity leading to pronounced clinical disease even without a change in virus transmissibility. This thesis demonstrates the application of serology and mathematical modelling to estimate pathogen prevalence. The data and inferences will be beneficial for guiding future policies focused on enterovirus epidemiology and disease burden. Certainly, better documentation of enterovirus true prevalence and collective impact on human health is warranted
Modelling wave breaking in envelope type models
Get PDFWave breaking in the ocean is a phenomenon crucial for understanding energy transfer, erosion processes, and climate modelling, and has an essential role in marine and coastal dynamics.
This thesis seeks to build surrogate models to enable fast breaking-wave prediction in non-linear Schrödinger-type (i.e., envelope-based) equations. We begin by revisiting four established models in the field, providing an evaluation of their methodologies, strengths, and limitations. Building on this foundation, we introduce the Modified Kato & Oikawa model, a novel approach that integrates key aspects of the existing Kato & Oikawa (1995, Journal of the Physical Society of Japan, 64(12), pp. 4660--4669) model while incorporating innovative mechanisms to more accurately represent the complexities of wave breaking.
To further advance the study of wave breaking dynamics, this thesis develops a machine learning (ML) model to capture the inherent nonlinearity of the process. Our early ML experiments---based on a synthetic dataset that is created using the Modified Kato & Oikawa model---suggest that the ML model can capture the dissipation from breaking waves.
In the next milestone, this thesis applies RANS (Reynolds-Averaged Navier--Stokes) simulations to generate a dataset that encompasses a wide range of wave breaking scenarios. This large dataset provides the foundation for training our ML model, ensuring that it is robust and capable of generalising across different conditions. Training of the ML model with the RANS dataset is the key contribution of this thesis, demonstrating the synergy between high-fidelity simulations and the ML model. The trained model demonstrates excellent agreement with the simulations and experiments, offering a performance that surpasses existing models
Approaches to supporting and measuring mathematical problem posing: a systematic review of interventions in mathematics education
Get PDFMathematical problem posing, a form of authentic mathematical inquiry and creation, has been
acknowledged as important by educators and curriculum frameworks internationally and has been
the focus of several intervention studies with students and teachers. However, the intervention
components and measured outcomes of these prior studies varied, highlighting the diverse
approaches researchers have taken to support and measure mathematical problem-posing
competence. In this systematic review, we examined 39 intervention studies published over the
past three decades, all aimed at developing mathematical problem-posing competence, and we
identified nine common intervention components suggested or utilized within these studies. Also,
we derived clusters of measured outcomes related to mathematical problem-posing competence
used in the interventions. Our findings deepen understanding of approaches to supporting and
measuring mathematical problem-posing competence, thus casting light on what works, including
methods for measuring progress, in problem-posing interventions. We discuss implications of our
findings for future research and practice
Complex mosaic landscapes: novel methodologies to understand dynamics of cocoa farming in Ghana
Get PDFComplex mosaic landscapes are some of the most prolific and important in the tropics. Often consisting of a mixture of small scale agriculture, natural vegetation and settlements, these areas support the livelihoods of hundreds of thousands of people and are the backbone of some globally important crops, such as cocoa. These landscapes are inherently complex due to the presence and interaction of numerous social and environmental factors across multiple spatial and temporal scales. Given the importance and abundance of these landscapes, disproportionately little is known about the patterns and processes which sustain or disrupt them.
This thesis aims to advance the understanding of complex mosaic landscapes by using novel methodologies to capture and analyse the patterns and processes of these systems. Cocoa farming landscapes surrounding Kakum National Park in southern Ghana are used as a case study. Data were acquired in three distinct regions surrounding the park, namely the area surrounding the villages of Aboabo , Ahomaho and Kwameamoabeng.
This thesis first presents detailed methods for undertaking Unmanned Aerial Vehicle surveys using commercially available equipment with RGB cameras. Next a detailed account of how to processes this imagery using commercially available softwares is outlined. The first data chapter of this thesis examines using machine learning approaches to classify land use within complex mosaic landscapes only using RGB drone imagery. These first chapters highlight the significant insights generated by this thesis towards capturing the patterns of complex mosaic landscapes in the tropics. The later part of the thesis focuses on the dynamics and processes which govern complex mosaic landscapes by framing them as social-ecological systems. The second data chapter provides a detailed summary of land use in the area of study while also quantifying the impact of humans on the environment by calculating and comparing the Human Appropriated Net Primary Productivity between the three study regions. The final data chapter presents a study of the dynamics between humans and the environment during a climatic shock perturbation. Using combination of social, environmental and spatial data the resilience of households is assessed. Indicators of resilience are then compared at a regional scale to understand some of the multi-scale dynamics of resilience to the climate shock. The thesis is then concluded and future research directions are identified
Specific ion effects enhance local structure in zwitterionic osmolyte solutions (data)
No full textSupporting data and simulation files for the neutron and X-ray scattering measurements analysed and discussed in the associated manuscript