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Canonization of a random circulant graph by counting walks
Get PDFIt is well known that almost all graphs are canonizable by a simple combinatorial routine known as colour refinement, also referred to as the 1-dimensional WeisfeilerβLeman algorithm. With high probability, this method assigns a unique label to each vertex of a random input graph and, hence, it is applicable only to asymmetric graphs. The strength of combinatorial refinement techniques becomes a subtle issue if the input graphs are highly symmetric. We prove that the combination of colour refinement and vertex individualization yields a canonical labelling for almost all circulant digraphs (i.e., Cayley digraphs of a cyclic group). This result provides first evidence of good average-case performance of combinatorial refinement within the class of vertex-transitive graphs. Remarkably, we do not even need the full power of the colour refinement algorithm. We show that the canonical label of a vertex v can be obtained just by counting walks of each length from v to an individualized vertex. Our analysis also implies that almost all circulant graphs are compact in the sense of Tinhofer, that is, their polytops of fractional automorphisms are integral. Finally, we show that a canonical Cayley representation can be constructed for almost all circulant graphs by the more powerful 2-dimensional WeisfeilerβLeman algorithm
Suicide prevention in Latin American prisons:a multiple case study with meta-matrix of policies, programmes and protocols in 17 countries
Get PDFBACKGROUND: Suicide is one of the most common causes of death in correctional settings. This study aimed to analyse prison suicide prevention policies and procedures across Latin America. METHODS: For this multiple case study, we collected data on prison suicide prevention in policies (laws), programmes (institutional framework) and protocols (procedures) from 17 Latin American countries, from (1) the public domain and (2) archival records held by prison administrations. The search was conducted using Google, through hand search on prison administration websites and requests to public information departments and prison administrations. Theory-driven thematic analysis was conducted based on 11 key components of suicide prevention in prison. Presence and quality of policies, programmes and protocols were assessed using tailored instruments. Between-country comparisons were made by cross-case analysis. RESULTS: Data were retrieved from 17 Latin American jurisdictions. Nine cases had a policy or law, 6 had an institutional plan or programme and 13 had suicide prevention protocols. In 6 of the 17 cases (Argentina, Chile, Colombia, Ecuador, Mexico and Panama), the three elements were present. Among the 13 cases with protocols, 7 (Argentina, Brazil, Chile, Colombia, Mexico, Paraguay and Uruguay) had high, 2 had medium and 4 cases had low quantity and quality of key components. In the composite quality assessment of policies, programmes and protocols, three cases (Argentina, Colombia and Mexico) had high quality, four cases had medium quality and the other seven cases had low quality of suicide prevention in place. CONCLUSION: Many Latin American countries still need to draft policies and develop institutional frameworks for suicide prevention in prison. Most countries may review their suicide prevention protocols in prisons to cover all key components with clear procedures. Prison administrations in Latin America should publish internal plans and protocols for prison suicide prevention to facilitate cross-country policy evaluations and research
Cueing autobiographical memory in young and older adults: an exploration of the effect of cue type on retrieval rates and memory characteristics
Get PDFCurrent theories of autobiographical memory (AM) emphasise the involvement of several non-memory auxiliary processes, such as executive function and mental imagery. However, the contribution of these processes to AM retrieval under different circumstances remains poorly understood, particularly in the context of ageing. The extent to which different AM tasks rely on auxiliary processing could explain variability in age-related AM deficits across different contexts. The current study explores the effect of cues varying in format (words, questions, sentences, photos, and videos) and content (e.g., event cues, evaluative cues, imagery cues) on AM retrieval rates in young and older adults. In Experiment 1, young and older adults (nΒ =Β 101) retrieved AMs in response to a set of 208 cues; dependent variables were the proportion of cues that produced a memory, and ratings of the characteristics of the retrieved memories. Results showed that retrieval rates were influenced by both cue format and cue content, with cues that most closely mapped the task requirements producing the largest proportion of memories, regardless of other cue features (e.g., detail, imagery). Study 2 collected data from a separate group of 106 adults concerning their interpretation of the same cues, and analysed the responses in relation to the data from Experiment 1. Both retrieval rates and memory characteristics were related to features of the cues, such as specificity, theme, and emotional content. Data suggested that less easily accessed memories tended to be more autobiographically important. All materials and data - including 2500 brief descriptions of participants' autobiographical memories - are freely available for further exploration
Autonomous recognition of erroneous raw key bit bias in quantum key distribution
Get PDFAs quantum key distribution technologies mature, it is pertinent to consider these systems in contexts beyond lab settings, and how these systems may have to operate autonomously. To begin, an abstract definition of a type of error that can occur with regard to the ratio of bit values in the raw key is presented, and how this has an impact on the security and key rate of QKD protocols. A mechanism by which errors of this type can be autonomously recognised is given, along with simulated results. A two part countermeasure that can be autonomously put in place to mitigate against errors of this type is also given. Finally some motivating examples where this type of error could appear in practice are presented to add context, and to illustrate the importance of this work to the development of quantum key distribution technologies
A comprehensive empirical and theoretical analysis of batching algorithms for efficient, safe, parallel mutation analysis in rust
No full textThere is a lack of serious tooling for mutation analysis for Rust, a safety-focused systems programming language seeing increased adoption across the industry. As such, the testing technique has not been widely used on programs written in the language as of yet. Without robust mutation analysis, Rust developers cannot determine test thoroughness. In response to this challenge, we designed a mutation analysis pipeline for Rust, which overcomes the challenges of generating valid mutants caused by the strictness of the language. Our approach accounts for Rustβs distinction between safe and unsafe operations, ensuring that safe mutations of valid Rust programs Γ those with only valid unsafe code sections Γ can be safely evaluated within the same process, without the potential for crashes or other undefined behavior invalidating the mutation analysis. We introduce mutation batching, our novel technique for efficiently evaluating multiple mutations simultaneously, while guaranteeing they do not interact. Batching maximizes thread usage, by executing significantly more test cases in parallel. As batching is NP-hard, we present multiple fast approximation algorithms for grouping mutations. We implemented our techniques into a mutation analysis tool, mutest-rs, which we used in our empirical evaluation on a diverse set of 22 Rust libraries and programs. We found that mutation batching reduces the overall runtime of mutation analysis by up to 52.3% and also saving 73.8 seconds in one case, and that unsafe mutations are detected at a lower rate, of up to 53.4%. Our mutation analysis tool is available at https://mutest.rs
Re-evaluating Boundary Conditions of the Concept of Life
Get PDFIt is argued that a central challenge to the task of developing a foundational model for life lies within the implicit propositions of the Western scientific view. These propositions constrain thinking about the concept of life. Three implicit boundary conditions in particular - life as a property of a system, life as a purely biological phenomenon, and life as a binary concept - are identified, and it is suggested to replace them with three operational principles - synonymity of βlifeβ with βprocesses of changeβ; the foundation of change upon interaction; the recursion and integration of change over boundary conditions
Informality in architectural heritage: A conceptual framework for inclusive conservation practice
Get PDFThe role of informality in architectural heritage conservation has remained underexplored despite its increasing significance in urban governance and community-led preservation. This study develops a conceptual framework to define and analyse informality within the context of tangible cultural heritage. Drawing on interdisciplinary insights from architecture, urban planning, and anthropology, the paper addresses the lack of theoretical clarity and empirical grounding in existing conservation literature. Using a systematic literature review of 24 peer-reviewed articles published between 2000 and 2025, the research identifies key attributes, such as adaptability, non-regulation, political negotiation, and community agency. It maps these across four dimensions: informal actors, practices, spaces, and governance. The findings underscore that the informal practices, often excluded from formal frameworks, play a crucial role in sustaining architectural heritage, especially in regions with limited institutional capacity. These practices include grassroots-led maintenance, vernacular adaptation, and public participation in decision-making. The study proposes an inclusive, bottom-up model integrating informal actors and practices with formal conservation policies. It advocates for institutional recognition of community contributions, development of capacity-building initiatives, and flexible policy design to accommodate informal dynamics. The proposed framework aims to support more sustainable, inclusive, and locally grounded approaches to heritage conservation, particularly relevant in urban areas of the Global South
Development of calcium sulfoaluminate-belite cements for the encapsulation of radioactive waste
No full textTo demonstrate and evaluate the potential of calcium sulfoaluminate-belite (CSA) cements for the enhanced encapsulation of future higher activity waste treatment processes, a commercially available clinker was trialled on a 3 L scale, before being scaled up to 500 L scale, using a typical In-Drum mixing (IDM) methodology and equipment employed for the encapsulation of radioactive slurry wastes in the UK. The formulation envelope varied the gypsum addition, water to solid ratio, and mixing shear regime. Mixes were conducted neat, with no addition of waste material, additives, supplementary cementitious materials, or fillers. Conducting IDM standard mixes allowed for the trial of formulations in absence of waste loading during operations, subjecting products to hydration exotherm temperatures based upon the scale of the products cast in excess of normal operations, where waste incorporation would be expected to dilute the peak hydration exotherm obtained. This scenario allows for the behaviour of the main CSA strength giving phase ettringite to be evaluated, establishing a bounding case. Following a curing duration of 28 and 90 d, the phase assemblage between products subjected to different curing exotherms were indistinguishable, despite being subjected to a range of different temperature profiles and the structure of the 500 L products being compromised. Processing properties were consistent between mixing scales, with physical properties producing desirable results when not impacted by the high exotherm temperatures experienced by 500 L products
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