University of St Andrews Research Portal
Not a member yet
81329 research outputs found
Sort by
Type systems and maximal subgroups of Thompson's group <i>V</i>
No full textWe 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
Indian women, refugees, and decolonisation across India, British Malaya, and China, 1940-1953
No full textThis article studies two refugee political communities, the Indian National Army (INA) and Faridabad, during the 1940s. It follows two Indian women who supported the refugees: the captain of the INA’s women’s regiment, Lakshmi Sahgal (née Swaminadhan, 1914–2012), and the socialist freedom fighter Kamaladevi Chattopadhyay (1903–88). Indian and Chinese anti-colonialism and working-class protests in Malaya inspired the INA’s war against British rule in India and Southeast Asia. This article conceptualizes the INA as a refugee polis, comprising Indians displaced by Japanese and British imperialism. Uprooted by the Partition of India, the refugees in Faridabad brought practices of state evasion from the Indo/Pak-Afghan borderlands. Kamaladevi and the Indian Cooperative Union helped organize them into a refugee polis. Thus, the INA and Faridabad, shaped by imperial crises and decolonization, emerged as two refugee poleis. They embodied political alternatives to the nation-state as an outcome of decolonization. The refugees advocated direct democracy, egalitarian redistribution of land, and co-operative economic management. The postcolonial Indian state saw this as a challenge. It transformed refugees into workers, whose labour would generate profits for the state. Although the refugees protested through unionization, strikes, and civil disobedience, ultimately, the Nehruvian state brutally suppressed these refugee poleis
Quantitative proteomics identifies plasma protein alterations that associate with metabolic and thrombotic profile changes after bariatric surgery
No full textObjective Roux-en-Y gastric bypass (RYGB) surgery has been shown to lead to favourable health outcomes in obese patients. However, the molecular changes that occur and how they relate to clinical measures are poorly understood. Here we characterise the proteomic alterations that occur in plasma of RYGB patients before and 9 months after surgery using quantitative proteomics.Methods Plasma proteomics was performed by sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) to identify and quantify differentially abundant proteins. Relationships between significantly altered proteins and clinical markers were examined. A gene set enrichment analysis was also conducted to identify altered pathways.ResultsFrom the proteomic analysis, 27 proteins increased, and 43 proteins decreased in abundance 9 months after surgery, providing insights into the physiological changes that accompany weight loss. Proteins including sex hormone binding globulin (SHBG), inter-alpha-trypsin inhibitor heavy chain 3 (ITIH3), and apolipoprotein D (APOD), which increased in abundance post-surgery, highlight improvements in lipid regulation, insulin sensitivity, and inflammation. Proteins involved in coagulation, including α2-macroglobulin, kallikrein-B1, prothrombin, factor (FX, FXI, and FXII), exhibited reduced levels, aligning with a decreased in thrombotic potential.Conclusions These findings provide a mechanistic understanding of how bariatric surgery leads to systemic changes in metabolic and haemostatic pathways, thus favourably modulating the risk of developing cardiovascular disease.<br/
A character theoretic formula for base size
No full textA base for a permutation group G acting on a set Ω is a sequence B of points of Ω such that the pointwise stabiliser GB is trivial. The base size of G is the size of a smallest base for G. We derive a character theoretic formula for the base size of a class of groups admitting a certain kind of irreducible character. Moreover, we prove a formula for enumerating the non-equivalent bases for G of size l ∈ ℕ. As a consequence of our results, we present a very short, entirely algebraic proof of the formula of Mecenero and Spiga for the base size of the symmetric group Sn acting on the k-element subsets of {1, 2, 3,...,n}. Our methods also provide a formula for the base size of many product type permutation groups
Leveraging an epidemic to establish vaccine clinical trial capacity in a low resource setting:the Ugandan experience
No full textBackground Pandemics have increasingly become more frequent. Globally, between 1970 and 2016, a total of over 1770 disease outbreaks of 38 known and two unknown causes were reported. Vaccines are a key medical countermeasure for most of these outbreaks, however, most of these are developed and tested outside Sub-Saharan Africa. There is underrepresentation of Africa in vaccine clinical trials. This is attributed to poor visibility of existing sites, limited infrastructure and unpredictable regulatory timelines, and lack of capacity and infrastructure for basic science research.Main text We draw on lessons from an Ebola outbreak in Uganda to suggest key factors to establishing a vaccine trial site in a low resource setting. The factors are trained clinical trial staff, availability and adaptation of generic trial protocols, establishment of vaccine cold chain storage facilities, south-south collaborations, in-country stewardship, and close collaboration with ethical and regulatory bodies.Conclusion African institutions could capitalise on the epidemics and the accompanying responses to build capacity for vaccine trials and position themselves to take part in global vaccine trials
CRB2 depletion induces YAP signaling and disrupts mechanosensing in podocytes
No full textFocal segmental glomerulosclerosis (FSGS) is a histologic lesion caused by a variety of injurious stimuli that lead to dysfunction/loss of glomerular visceral epithelial cells (i.e., podocytes). Pathogenic mutations in crumbs homolog-2 (CRB2), encoding the type 1 transmembrane protein crumbs homolog-2, have been shown to cause early-onset corticosteroid-resistant nephrotic syndrome (SRNS)/FSGS. Here, we identified a two-generation Indian kindred (DUK40595) with biopsy-proven SRNS/FSGS caused by a compound heterozygous mutation in CRB2 comprised of the previously described truncating mutation p.Gly1036_Alafs*43 and a rare 9-bp deletion mutation p.Leu1074_Asp1076del. Because compound heterozygous mutations involving the truncating p.Gly1036_Alafs*43 variant have been associated with reduced CRB2 expression in podocytes and autosomal recessive SRNS/FSGS, we sought to define the pathogenic effects of CRB2 deficiency in podocytes. We show that CRB2 knockdown induces yes-associated protein (YAP) activity and target gene expression in podocytes. It upregulates YAP-mediated mechanosignaling and increases the density of focal adhesion and F-actin. Using elastic resonator interference stress microscopy (ERISM), we demonstrate that CRB2 knockdown also enhances podocyte contractility in a substrate stiffness-dependent manner. The knockdown effect decreases with increasing substrate stiffness, indicating impaired mechanosensing in CRB2 knockdown cells at low substrate stiffness. Although the mechanical activation of CRB2 knockdown cells is associated with increased YAP activity, the enhanced cell contractility is not significantly reduced by the selective YAP inhibitors K-975 and verteporfin, suggesting that multiple pathways may be involved in mechanosignaling downstream of CRB2. Taken together, these studies provide the first evidence that CRB2 deficiency may impair podocyte mechanotransduction via disruption of YAP signaling in podocytes
Counter-radicalisation case management interventions:findings from a Campbell systematic review
No full textThis article sets out the findings of a Campbell systematic review examining the effectiveness and implementation of case management tools and approaches used to counter radicalisation to violence. This review found that the effectiveness of these tools and approaches remains poorly understood owing to the continued absence of robust impact evaluations. However, by breaking the case management process down into its constituent parts, from client identification to client assessment; case planning, implementation and delivery; monitoring and evaluation; through to exit and transition, this review was able to uncover a robust body of evidence relating to the implementation of different stages of the case management process, and programmes as-a-whole. Based on an analysis of 47 studies, the systematic review identified a range of factors that support the effective implementation of case management interventions. These include the availability of relevant tools; strong multi-agency working arrangements; intervention teams holding relevant knowledge and expertise; and adequate resourcing. In contrast, the absence of these factors can inhibit implementation, as can reliance on overly risk-oriented logics; public and political pressure; and the features of the legislative context within which programmes are delivered. The paper concludes by outlining the implications of the review, and discusses avenues for future research
Trends in indicators of violence among adolescents in Europe and North America 1994-2022
No full textObjectives: To describe age and gender specific time trends in adolescent violence across 19 countries over 28 years.Methods: The paper presents analysis of eight cycles of the Health Behaviour in School-aged Children (HBSC) Study from 1994–2022, involving 789,531 children aged 11, 13, and 15. Indicators of violence included physical fighting, school bullying and cyberbullying (from 2018). Log-binomial regression models were used to test for linear temporal trends, with Generalized Estimating Equations used to account for clustering by country.Results: School bullying perpetration and victimization declined over time in each age/gender group in most countries. Similar declines were reported for frequent physical fighting among boys (all ages) and girls (age 15 only). The prevalence of violent behaviour was almost universally higher in boys in the early cycles than in girls, but this gender difference attenuated over time. For cyberbullying, significant increases were observed since 2018 in all groups except age 15 girls in most countries.Conclusion: This analysis of a large cross-national dataset suggests a decline in traditional forms of adolescent violence. However, the increases in cyberbullying warrant further monitoring
Problems and solutions when quantifying nitrogen in silicate and oxide minerals and glasses using electron probe microanalysis
No full textWith growing interest in the Earth's deep nitrogen cycle, electron probe microanalysis is increasingly used to quantify nitrogen in minerals and glasses. However, measuring nitrogen by electron microprobe comes with challenges, including beam sensitivity and differences in peak and background shapes between sample and reference materials. This study provides a robust analytical protocol to addresses these issues. We gathered mineral and glass reference materials with known nitrogen mass fractions from previous work, and synthesised additional glasses with nitrogen quantified independently by gas-source mass spectrometry. Our method uses nitrides as calibration materials because of their beam stability and high nitrogen mass fraction. We assess peak shapes to implement an area-peak factor correction, and account for curved backgrounds using a four-point background correction. Importantly, we describe how to estimate uncertainties on both background and area-peak factor corrections, which is required to assess detection limits but has been largely overlooked in previous studies. Our method yields nitrogen mass fractions within uncertainty for five out of seven reference materials, with two exceptions highlighting the need for further refinement. We provide Python code for applying the corrections and calculating uncertainties, allowing our method to be implemented by any researcher with access to an electron microprobe laboratory