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Brief announcement : exploring word-representable temporal graphs
Get PDFWord-representable graphs are a subset of graphs that may be represented by a word w over an alphabet composed of the vertices in the graph. In such graphs, an edge exists if and only if the occurrences of the corresponding vertices alternate in the word w. We generalise this notion to temporal graphs, constructing timesteps by partitioning the word into factors (contiguous subwords) such that no factor contains more than one copy of any given symbol. With this definition, we study the problem of exploration, asking for the fastest schedule such that a given agent may explore all n vertices of the graph. We show that if the corresponding temporal graph is connected in every timestep, we may explore the graph in 2δ n timesteps, where δ is the lowest degree of any vertex in the graph. In general, we show that, for any temporal graph represented by a word of length at least n(2dn + d), with a connected underlying graph, the full graph can be explored in 2 d n timesteps, where d is the diameter of the graph
The diffusion of cooperative and solo bubble net feeding in Canadian Pacific humpback whales
Get PDFFunding: Carol Newell with the Endswell Foundation - 2018-2024; Donner Canadian Foundation - 2018-2024; Government of Canada Habitat Stewardship Program for Species at Risk - HSP-PAC, 2012-2024; Leslie & Charles Hilton Brown PhD Scholarship Fund - 2022-2025; Liz Haan - 2017-2024; Save Our Seas Foundation - 217, 2010-2024; The Makeway Foundation; Willow Grove Foundation - 2010-2024; World Wildlife Fund Canada - 2010-2020; Zumwalt Family - 2010-2020.Animal culture, information and behaviours acquired and shared by social learning are a form of biodiversity with intrinsic and practical value. Cooperative foraging, a mutualistic resource acquisition behaviour observed across diverse taxa, is strongly connected to social networks via behavioural states, cues and often social learning, as it typically involves high interaction rates. Understanding the distribution, diffusion and learning mechanisms of such cooperative behaviours is an important but understudied aspect of nonhuman culture. Bubble net feeding (‘bubble netting’) is a specialized foraging technique practised by certain humpback whale (Megaptera novaeangliae) populations globally. Over 20 years in the northern Canadian Pacific, we observed the diffusion of two forms: cooperative group and independent (or ‘solo’) bubble netting. Network-based diffusion analysis—a tool to test for social learning—finds strong evidence for social learning of bubble netting when the overall social network is used, even after accounting for traits such as site fidelity and sex (10.6 × 103 to 35.4 × 103 times more support for social versus asocial learning; p < 0.0001). A homophily check using pre-acquisition association data returned ambiguous results, likely due to the inherent sociality of this cooperative foraging behaviour. Nonetheless, the rapid diffusion of bubble netting is clearly important for population viability and should inform conservation planning for this threatened population.Peer reviewe
A millimeter methanol maser ring tracing the deceleration of the heat wave powered by the massive protostellar accretion outburst in G358.93–0.03 MM1
Get PDFFunding: C.J.C. acknowledges support from the STFC (grant ST/Y002229/1). R.A.B acknowledges support from the Latvian Council of Science project “A single-baseline radio interferometer in a new age of transient astrophysics (IVARS)” (grant No. lzp-2022/1-0083).We present multiepoch, multiband Atacama Large Millimeter/submillimeter Array imaging of the new Class II millimeter methanol masers excited during the accretion outburst of the massive protostar G358.93−0.03 MM1. The highest angular resolution image (24 mas ≈160 au) reveals a nearly complete, circular ring of strong maser spots in the 217.2992 GHz (vt = 1) maser line that closely circumscribes the dust continuum emission from MM1. Weaker maser emission lies inside the eastern and southern halves of the maser ring, generally coincident with the centimeter masers excited during the outburst but avoiding the densest parts of the hot core gas traced by high excitation lines of CH3CN. Using a variety of fitting techniques on the image cubes of the two strongest maser lines, each observed over three to four epochs, we find the diameter of the ring increased by ≳60% (from ≈1100 to ≈1800 au in the 217 GHz line) over 200 days, consistent with an average radial propagation rate of ≈0.01c, while the maser intensity declined exponentially. Fitting the angular extent of the millimeter masers versus time yields a power law of index 0.39 ± 0.06, which also reproduces the observed extent of the 6.7 GHz masers in the first very long baseline interferometry epoch of R. A. Burns et al. 2020 This exponent is consistent with the prediction of radius versus time in the Taylor–von Neumann–Sedov self-similar solution for an intense spherical explosion from a point source (R ∝ t2/5). These results demonstrate the explosive nature of accretion outbursts in massive protostars and their ability to generate subluminal heat waves traceable by centimeter and millimeter masers for several months as the energy traverses the surrounding molecular material.Peer reviewe
Federal alternative to the unitary British state, 1850-1950
No full textThis thesis investigates a federal tradition in British political and constitutional thought from 1850 to 1950. It uses four major figures as case studies: Lord Acton, James Bryce, John Neville Figgis, and Harold Laski. From them a brand of liberal federalism emerges that is subsequently developed within socialist thought. These figures are concerned with challenging the ascendant unitary theory of the British state articulated by A. V. Dicey and transformed into a dominant orthodoxy within the mainstream of British Conservative-Unionist and Labour politics.
Two major themes run through the thesis. Firstly, it aims to show how the federal tradition is more closely related to subsequent pluralist ideas than has previously been appreciated. Secondly, it examines challenges to British unitarism before, during, and after the publication of Dicey’s seminal Introduction to the Study of the Law of the Constitution in 1885.
Emphasis is placed on a continuous tradition of thought that develops between the eras of Acton and Laski. Concern with federalism emerges in the late 1850s as a reaction to European nationalism. Interest grew as the American Civil War placed a disputed federal constitution at the forefront of political discourse; in the 1870s and 1880s the Irish question raised similar debates in Britain. The political pluralism of Figgis and Laski was shaped by a non-territorial brand of federalism with its genealogical roots in Acton.
Read as an examination of unitarism, Acton offers a pre-Diceyan interpretation of the British constitution that was looser, historicist, and, as such, less narrowly constricted. Bryce provides insight into the immediate context of Diceyan unitarism as it emerged. His jurisprudence illustrates an attempt to reconcile federal institutions with indivisible sovereignty via scientific analogy. Figgis and Laski reflect a post-Diceyan perspective that moves the debate away from formality and towards a pragmatic analysis of real life
Dominating experiences : psychic and symbolic violence against Romani women in Hungary
Get PDFThis chapter explores violence against Romani women in Hungary, not as individual discrimination or institutional racism, but as unconscious aggression that socializes and legitimizes violence. The chapter builds on the theoretical work of Pierre Bourdieu, who argued that there are forms of violence beyond the physical, including symbolic violence, which normalizes structural and physical violence in the repetitions of everyday speech. Through an application of theoretical contributions of the Hungarian psychoanalyst Sándor Ferenczi, the chapter introduces an additional form of violence: psychic violence, which is the unconscious denial of the subjective experiences of those imagined to be targets, imagined to be “other”. The chapter concludes with Ferenczi’s argument that in order to overcome such violence, each of us must reflect on the ways in which we might act out aggression on others, not only in terms of physical violence, but also the in ways that we speak and think
Exsolution of nanoparticles from doped LaAlO₃ perovskite at low temperature for reversible solid oxide cell electrode applications
No full textThe need to meet rising worldwide energy demand has accelerated the creation and implementation of new technologies and renewable energy sources to progressively replace fossil fuels as the dominant energy providers. Unfortunately, the full replacement of these conventional sources is still far from becoming a reality due to multidimensional factors that are economic, environmental, geopolitical, strategic, and technical in nature. Although not all of the problems can be solved at once, much remains to be done with regards to the technical aspect.
There is always a need to develop creative ways to surpass specific challenges, and in the case of current renewable sources, one outstanding obstacle is energy storage. The production of green hydrogen through use of reversible solid oxide cells could offer an alternative solution to conventional battery systems. However, like any other technology, solid oxide cells have their own limitations. This is especially true with the fuel-side electrode, where NiO continues to dominate as the material of choice. Continuous development of a new generation of electrodes with reduced content of critical raw materials and improved electrochemical performance is essential to find an alternative to NiO based electrodes. One promising approach is the combination of exsolution and defects introduced via doping in perovskite oxides. In this work, the operating conditions of the reversible solid oxide cells was taken advantage of to exsolve metallic nanoparticles on the perovskite electrode material surface. It has been proven that well-anchored and dispersed exsolved metallic nanoparticles exhibit both higher electrocatalytic activity as well as better stability via agglomeration resistance when compared to NiO. However, one drawback with exsolution is that it typically requires high temperatures and highly reducing environments to be triggered. In this work, the material properties of LaAlO₃ were enhanced to achieve exsolution at 500°C as well as improving electrochemical performance.
This research explores the implementation of doped-LaAlO₃ perovskite oxide, a material with excellent capabilities for exsolution, for Reversible Solid Oxide Cell (r-SOC) electrode applications at temperatures below 600°C. This work follows a pathway that starts with synthesis optimisation and continues to the final application of the material as a fuel-side electrode in a device operating below 600°C. Various complications were encountered along the way and solved in turn, ultimately leading to remarkable results in exsolution."This work was supported by the the University of St Andrews, the EPISTORE EU H2020 project (101017709), the EPSRC Light Element Analysis Facility Grant (EP/T019298/1), and the EPSRC Strategic Equipment Resource Grant (EP/R023751/1)."--Fundin
Biocompatible TADF probes for highly multiplexed fluorescence lifetime imaging
Get PDFFunding: The authors thank the EPSRC (EP/X525819/1, EP/Z535291/1, EP/W007517/1, EP/W015137/1) for financial support. P. S. C thanks the Xunta de Galicia for her predoctoral contract (ED481A-2023-140). J. H. acknowledges funding from the Studienstiftung des deutschen Volkes. C. G. B. acknowledges the financial support from the Axencia Galega de Innovación (GAIN) [ED431C 2025/05 and Centro Singular de Investigación de Galicia accreditation 2024–2027 (ED431G 2023/03)] and the European Regional Development Fund. M. V. acknowledges funding from an ERC Consolidator Grant (DYNAFLUORS, 771443).Fluorescence lifetime imaging microscopy (FLIM) is an optical imaging modality that can provide multiplexed readouts with remarkable sensitivity to cellular microenvironments. Even though fluorescence lifetimes can distinguish fluorophores having overlapping spectral profiles, conventional fluorophores possess a narrow range of emission lifetimes (typically shorter than 5 ns) that limits their potential for multiplexed imaging. In this work, we have systematically designed and evaluated a combination of thermally activated delayed fluorescence (TADF) nanoprobes for multiplexed FLIM. We have synthesized a collection of 36 TADF biocompatible nanoprobes with long and diverse fluorescence lifetimes in aqueous media (up to 15 ns) and employed selected probes for live-cell imaging of bacterial cells under physiological conditions. By leveraging the exceptionally broad range of fluorescence lifetimes of these TADF emitters, we have achieved unprecedented simultaneous imaging of five nanoprobes within a single spectral window using a FLIM-phasor strategy. These findings demonstrate that TADF emitters are excellent scaffolds to unlock the capabilities of fluorescence lifetime imaging for multi-color biological studies.Peer reviewe
Cervical whole-slide images dataset for multiclass classification
Get PDFFunding: This work is supported by the Industrial Centre for AI Research in digital Diagnostics (iCAIRD), which is funded by Innovate UK on behalf of UK Research and Innovation (UKRI) [project number: 104690] and in part by Chief Scientist Office, Scotland.Background: The clinical pathway for the prevention and treatment of cervical cancer depends on cytology and then the assessment of biopsy specimens, fragments of tissue removed for histological examination. This can be a significant workload and is an obvious exemplar to explore triage based on machine learning analysis of slides. Limited access to large annotated datasets of human diseased tissue is a major obstacle to developing standards and algorithms that can assist diagnosis. Results: We present a dataset comprising 2,539 whole-slide images of cervical biopsy specimens, each annotated by several pathologists and consensus on diagnosis and individual features agreed. Each whole-slide image represents 1 slide per patient in iSyntax format, with manual annotations by pathologists in Jason format. Each whole-slide image is assigned a category label, which is the final diagnosis of the image, and a subcategory label, which declares in which subcategory the image is found. Conclusion: This dataset has been used to build a model that accurately predicts diagnosis, allowing the possibility of automatically triaging biopsy specimens, so that the most significant pathologies can be identified rapidly and those patients selected for immediate treatment. The level of annotation, at the subslide level, and the number of cases are unique in public databases and should allow investigators to explore multiple aspects of computer vision relevant to human tissue diagnosis, with no limitation placed on access to the whole-slide images.Peer reviewe
The accordion’s evolution within the classical music canon : aesthetic innovation and philosophical perspectives
Get PDFThe accordion's role in classical music expanded substantially during the twentieth century. Technical advancements enabled an instrument with folk origins to accommodate new levels of tonal and polyphonic structure, facilitating integration into classical repertoire. The accordion is now an established instrument in solo, chamber and orchestral genres, with a growing presence in contemporary composition and academic curricula.
This research portfolio aims to advance the accordion's place in classical music in the process of critically examining its evolving role. The portfolio comprises three connected projects, each contributing to improved understanding of the accordion’s capabilities and its integration into the broader classical repertoire. These projects collectively contribute to the scholarly resources available for composers, performers and educators.
Project 1 focuses on transcriptions of varied repertoire originally composed for other instruments. It exemplifies the process of adaptation, the idiom of the original works meticulously reinterpreted for the accordion. Through this careful emulation, the project promotes reimagining basic musical ideas in a new sonic framework.
Project 2 investigates approaches to the accordion by composers either of Scottish heritage or residing in Scotland. They embody varied compositional styles and techniques, notably in new works specifically commissioned for the classical accordion. These compositions provide critical insights into the pedagogy, performance practices and contemporary compositional techniques associated with the instrument.
Project 3 covers the development of a comprehensive manual for scales, arpeggios and broken chords specifically designed for the classical accordion, including a free-bass supplement for each scale. It addresses a major gap in the teaching literature, particularly given the increasing prominence of free-bass systems in contemporary accordion repertoire. In offering a cohesive, rigorously researched educational resource, this project fills a vital pedagogical need.
The commentary outlines the practical and theoretical concepts that underlie the accompanying portfolio and provide a framework for understanding its contents
Improved abundance trajectories with Bayesian population dynamics models : case study with a Hawaiian honeycreeper
Get PDFFunding: Funding for R.J.C. was partially provided by the U.S. Geological Survey and partially through a studentship from Centre for Research into Ecological & Environmental Modelling, University of St Andrews.Many wildlife monitoring programmes collect annual data on population abundance. The resulting abundance estimates fluctuate over time partly because of true population change and partly because of observation error. These two components of variation can be separated by fitting the estimates to a population dynamics model within a Bayesian state-space modelling framework. By constraining the population trajectory to be biologically realistic, more precise estimates can be obtained. Independent biological knowledge can be incorporated through choice of model structure and by specifying informative prior distributions on demographic parameters. We illustrate the approach using a 31-year point transect study of the Hawai’i ’ākepa (Loxops coccineus). We fitted five models, each making different assumptions about how population change, recruitment and/or adult survival varied over time. Overall, the ’ākepa geometric mean growth rate was 1.02, indicating an increasing population over the 31-year time series, although there were periods of slow decline potentially associated with low recruitment and more rapid recovery associated with pulses of high recruitment. Abundance estimates derived from the population models were substantially more precise than the ‘raw’ point transect estimates: 95% credible interval (CrI) was on average 51.7% (s.d. = 14.1%) narrower.Peer reviewe
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