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Three-dimensional solar magnetic field extrapolation using analytical magnetohydrostatic equilibrium solutions
No full textThe majority of coronal magnetic field extrapolation methods use photospheric observations as boundary conditions together with the assumption of a force-free or even potential corona. However, observations suggest that the photosphere and chromosphere are not force-free and that, therefore, currents perpendicular to the magnetic field should be present in the lower layers of the solar atmosphere. As a result, to properly model these non-force-free regions, extrapolation methods based on magnetohydrostatic (MHS) equilibria are needed. Compared to force-free equilibria, MHS equilibria include the pressure gradient force and the gravitational force in addition to the Lorentz force. This thesis primarily investigates the potential of linear MHS extrapolation to become a practical, efficient and convenient tool for local coronal field modelling.
A detailed investigation is carried out into asymptotic solutions of a specific family of MHS equilibrium equations. This is important because these asymptotic solutions can help to increase the numerical efficiency of MHS models. In addition, theoretical and practical techniques are explored to enable the application of the analytical model presented in this thesis to observational data and to further reduce its computation time.
Using specialised codes which were written during the course of the work for this thesis, we demonstrate the capabilities of this new magnetic field extrapolation method. Furthermore, we test the results based on our method by comparing them to "ground-truth" data from other extrapolation methods and from MHD simulations. Furthermore, we present the very first applications of the newly developed tool to observational data. For these applications we use data by the Helioseismic Magnetic Imager onboard the Solar Dynamics Observatory, and by the Polarimetric and Helioseismic Imager onboard Solar Orbiter. Advantages and disadvantages of the model are discussed together with opportunities to further increase its efficiency. Although the code developed is not yet ready for public release, it has the potential to be developed into a publicly available tool for 3D MHS extrapolation for use by the broader scientific community
Type systems and maximal subgroups of Thompson's group V
Get PDFFunding: The first and second authors were partially supported by EPSRC grant EP/R032866/1 during the creation of this paper. The first author was also supported by the National Science Foundation under Grant No. DMS-185436. The fourth author was partially supported by the GIF grant I-198-304.1-2015, “Geometric exponents of random walks and intermediate growth groups,” LMS Grant 21806, NSF DMS–2005297 “Group Actions on Trees and Boundaries of Trees,” and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. 725773).We introduce the concept of a type system P, that is, a partition on the set of finite words over the alphabet {0, 1} compatible with the partial action of Thompson’s group V, and associate a subgroup StabV(P) of V. We classify the finite simple type systems and show that the stabilizers of various simple type systems, including all finite simple type systems, are maximal subgroups of V. We also find an uncountable family of pairwise nonisomorphic maximal subgroups of V. These maximal subgroups occur as stabilizers of infinite simple type systems and have not been described in previous literature: specifically, they do not arise as stabilizers in V of finite sets of points in Cantor space. Finally, we show that two natural conditions on subgroups of V (both related to primitivity) are each satisfied only by V itself, giving new ways to recognise when a subgroup of V is not actually proper.Peer reviewe
Improving the quality of weekend medical handover on non-receiving medical hospital wards
Get PDFIntroduction Handover is the system by which the responsibility for immediate and ongoing care is transferred between healthcare professionals and can be an area of risk. The Royal College of Physicians (RCP) has recommended improvement and standardisation of handover. Locally, national training surveys have reported poor feedback regarding handover at Glasgow Royal Infirmary. Aim To improve and standardise handover from weekday to weekend teams. Methods The Plan–Do–Study–Act (PDSA) quality improvement framework was used. Interventions were derived from a driver diagram after consultation with relevant stakeholders. Four PDSA cycles were completed over a 4-month period: PDSA cycle 1—Introduction of standardised paper form on three wards. PDSA cycle 2—Introduction of electronic handover system on three wards. PDSA cycle 3—Expansion of electronic handover to seven wards. PDSA cycle 4—Expansion of electronic handover to all non-receiving medical wards. The outcome of interest was the percentage of patients with full information handed over based on a six-point scale derived from the RCP. Data were collected weekly throughout the study period. Results 18 data collection exercises were performed including 525 patients. During the initial phase there was an improvement in handover quality with 0/28 (0%) at baseline having all six points completed compared with 13/48 (27%) with standardised paper form and 21/42 (50%) with the electronic system (p<0.001). When the electronic handover form was expanded to all wards, the increased quality was maintained, however, to a lesser extent compared with the initial wards. Conclusion A standardised electronic handover system was successfully introduced to downstream medical wards over a short time period. This led to an in improvement in the quality of handover in the initial wards involved. When expanded to a greater number of wards there was still an improvement in quality but to a lesser degree.Peer reviewe
Time-dependent nonlinear gravity–capillary surface waves with viscous dissipation and wind forcing
Get PDFFunding: J.S. and P.H.T. acknowledge support by the Engineering and Physical Sciences Research Council (EPSRC grant no. EP/V012479/1). J.S. was additionally supported by the Engineering and Physical Sciences Research Council (EPSRC grant no. EP/W522491/1).We develop a time-dependent conformal method to study the effect of viscosity on steep surface waves. When the effect of surface tension is included, numerical solutions are found that contain highly oscillatory parasitic capillary ripples. These small-amplitude ripples are associated with the high curvature at the crest of the underlying viscous-gravity wave, and display asymmetry about the wave crest. Previous inviscid studies of steep surface waves have calculated intricate bifurcation structures that appear for small surface tension. We show numerically that viscosity suppresses these. While the discrete solution branches still appear, they collapse to form a single smooth branch in the limit of small surface tension. These solutions are shown to be temporally stable, both to small superharmonic perturbations in a linear stability analysis, and to some larger amplitude perturbations in different initial-value problems. Our work provides a convenient method for the numerical computation and analysis of water waves with viscosity, without evaluating the free-boundary problem for the full Navier–Stokes equations, which becomes increasingly challenging at larger Reynolds numbers.Peer reviewe
Advances in tuberculosis biomarkers : unravelling risk factors, active disease and treatment success
Get PDFFunding: This project has received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement number 101007873. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and EFPIA, Deutsches Zentrum für Infektionsforschung e. V. (DZIF), and Ludwig-Maximilians-Universität München (LMU). EFPIA/AP contribute to 50% of funding, whereas the contribution of DZIF and the LMU University Hospital Munich has been granted by the German Federal Ministry of Education and Research.Tuberculosis (TB) is a major global health threat and demands improved diagnostic and treatment monitoring methods. Conventional diagnostics, such as sputum smear microscopy and culture, are limited by slow results and low sensitivity, particularly in certain patient groups. Recent advances in biomarker research offer promising solutions in three key areas: risk of disease, diagnosis of active disease and monitoring of treatment response. For risk assessment, novel genetic signatures and metabolites show potential in predicting the progression from TB infection to active TB. A 16-gene signature, for example, predicts this progression with significant accuracy. In diagnosing active TB, RNA-based transcriptomic signatures provide higher diagnostic accuracy than traditional methods. These signatures, such as a three-gene RNA sequence, effectively differentiate active TB from other diseases and infections, addressing issues of specificity and sensitivity. Monitoring treatment response is crucial, given the varying response rates in treating TB. Emerging biomarkers focus on bacterial burden and host response. They offer more precise and timely assessments of treatment efficacy, enhance personalised treatment approaches and potentially improve patient outcomes. These advancements in biomarkers for TB risk, diagnosis and treatment response represent significant steps towards more effective TB management and control, aligning with global efforts to decrease the burden of TB. Here we aim to highlight several promising biomarkers used to predict risk of disease progression, active TB disease and treatment success.Peer reviewe
The partnership context of childbearing
Get PDFWith non-marital cohabitation, union dissolution, and repartnering becoming increasingly common in the last few decades, partnership dynamics have become more complex than in the past. This implies that the share of children born to married parents has declined and, conversely, the share of children born to single, cohabiting, or repartnered parents has increased. This chapter begins with a description of the trends in non-marital childbearing across European and other Western societies. I briefly discuss the potential reasons for cross-national differences in these patterns and the main competing explanations underlying the observed patterns. This is followed by an overview of empirical research on the partnership context in which children are born in contemporary European and Western societies and potential socio-economic inequalities in these trends. The concluding section highlights gaps and directions for future research
Dancing with multiple sclerosis : a multidimensional and multiple case study
Get PDFDance health is a fast-developing field of practice and research focused on understanding the role of dance in enhancing physical, mental, and social well-being, both for general populations and individuals with specific health conditions. While the evidence base around dance for people with Parkinson’s is well-established, research on dance for other health conditions, such as multiple sclerosis (MS), is limited. As is known, this is the first thesis to focus on understanding the phenomenon of dancing with MS.
Unlike most prior dance for MS studies that have adopted medically-oriented, positivist, quantitative designs, the current research employs an interdisciplinary, critical realist, primarily qualitative methodology to 1) explore the health and well-being experiences of participant dancers with MS and 2) examine the factors affecting the impact and implementation of dance for MS programmes in different contexts. Using a case study approach, the research examines Scottish Ballet’s dance for MS programme, SB Elevate®, in two distinct contexts: Glasgow and Orkney. Data collection in both cases primarily involved semi-structured interviews, with the Glasgow case also drawing on observations, questionnaires, and a co-designed dance-based method of inquiry, movement interviews.
The findings indicate dance provides a valuable well-being resource for dancers with MS by fostering a sense of joy, purpose, and community. The study also illustrates the relational nature of the well-being experience, being shaped by people, place, and their interconnections within SB Elevate®. Proactive participants, interpersonal supports, responsive programming dynamics, and supportive community infrastructure emerged as key factors for enabling effective implementation, aligning the programme with participants’ preferences and local contexts. This research highlights the health-promoting potential of SB Elevate®, fostered by the interplay between the programme’s supportive environment and the dancers’ active commitment to well-being."This work was supported by the Thouron Award [2021 Award Cohort], and the final year of study [2023/2024] was supported in part by an RCS PhD Studentship."--Fundin
Common threads : clothing the body in post-9/11 political violence
No full textThis thesis examines the relationship between clothing and political violence through an interdisciplinary approach to five case studies situated within the War on Terror. Starting with the attacks of 11 September 2001, it analyses their occurrence within New York Fashion Week and consequent mediation by fashion writers and designers. After demonstrating how US citizens were militarised through clothing consumerism in 9/11’s aftermath, Chapter II discusses the early years of the US invasion into Iraq, critiquing the cultural conceptualisation of a ‘civilising force’. The failures of this concept are explored in analysis of the abuses enacted at Abu Ghraib prison, which establish the conditions for the political violence of the so-called Islamic State, the aesthetics of which, particularly those which were US-derived, are examined in Chapter III. The thesis then examines the repercussions of the War on Terror on domestic soil in the US Opioid Crisis. The disenfranchisement of identities discussed in Chapter IV — military, veteran and civilian — culminates in the rise of the militarised far- and alt-right through Donald Trump’s political ascendency, and the political violence enacted at the US Capitol on 6 January 2021, analysed in Chapter V. Power, and how it is aestheticised, granted, and denied through clothing, is fundamental to this thesis, which draws upon Giorgio Agamben’s interpretations of a ‘state of exception’, ‘sovereign’, and homo sacer. In studying the War on Terror through these five case studies, analysed through clothing and encompassing media, literature and images to discuss the political, cultural and aesthetic representations of the events, I argue that whilst clothing is commonly perceived as either marking individuality or informing group identity, it highlights the commonalities as well as demarcations between opposing identities within the War on Terror, and the precarious conditionality that underpins these identities and the power they wield
Silicon isotopic signatures of granitoids support increased weathering of subaerial land 3.7 billion years ago
Get PDFFunding: This project was founded by the Swiss National Science Foundation grant 181172 to N.D.G. The Neptune MC-ICP-MS at the University of Bern was acquired with funds from the National Centre for Competence in Research PlanetS, also supported by the Swiss National Science Foundation (SNSF). M.E.M. was supported by the University of St Andrews School of Earth and Environmental Sciences and the Handsel scheme, in addition to NERC grant NE/R002134/1 to P.S.S.The weathering and erosion of emerged land profoundly influences the Earth system, including the composition of the atmosphere and the type of nutrients delivered to the oceans. The emergence of land allowed for the formation of lakes and continental shelves, important habitats for the origin and evolution of life. Recent studies indicate a difference in silicon isotopes between Archean granitoids and their modern counterparts, which is explained by the incorporation of seawater-derived silica in the melting sources of the former. We show that this signature changed rapidly around 3.6 billion years ago, and that this shift is likely linked to an increase in the dissolved silicon flux from terrestrial weathering. Modeling suggests that the amount of oceanic silicon derived from terrigenous sources increased from near zero to around 32 ± 15% between 3.8 and 3.6 billion years ago. This indicates that, from this point onward, continental weathering feedbacks were established, and mass flux from land became an important source in the chemical budget of seawater, changes that likely exerted positive effects on the evolution of life.Peer reviewe
BioTIME 2.0 : expanding and improving a database of biodiversity time series
Get PDFFunding: H2020 European Research Council (Grant Number(s): GA 101044975, GA 101098020).Motivation: Here, we make available a second version of the BioTIME database, which compiles records of abundance estimates for species in sample events of ecological assemblages through time. The updated version expands version 1.0 of the database by doubling the number of studies and includes substantial additional curation to the taxonomic accuracy of the records, as well as the metadata. Moreover, we now provide an R package (BioTIMEr) to facilitate use of the database. Main Types of Variables: Included The database is composed of one main data table containing the abundance records and 11 metadata tables. The data are organised in a hierarchy of scales where 11,989,233 records are nested in 1,603,067 sample events, from 553,253 sampling locations, which are nested in 708 studies. A study is defined as a sampling methodology applied to an assemblage for a minimum of 2 years. Spatial Location and Grain: Sampling locations in BioTIME are distributed across the planet, including marine, terrestrial and freshwater realms. Spatial grain size and extent vary across studies depending on sampling methodology. We recommend gridding of sampling locations into areas of consistent size. Time Period and Grain: The earliest time series in BioTIME start in 1874, and the most recent records are from 2023. Temporal grain and duration vary across studies. We recommend doing sample-level rarefaction to ensure consistent sampling effort through time before calculating any diversity metric. Major Taxa and Level of Measurement: The database includes any eukaryotic taxa, with a combined total of 56,400 taxa. Software Format: csv and. SQL.Peer reviewe
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