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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
A General Theoretical Framework for Learning Smallest Interpretable Models
No full textWe develop a general algorithmic framework that allows us to obtain fixed-parameter tractability for computing smallest symbolic models that represent given data. Our framework applies to all ML model types that admit a certain extension property. By establishing this extension property for decision trees, decision sets, decision lists, and binary decision diagrams, we obtain that minimizing these fundamental model types is fixed-parameter tractable. Our framework even applies to ensembles, which combine individual models by majority decision
Placement of dedicated lanes for autonomous vehicles considering the changes of urban spatial structure
No full textThis paper investigates the placement schemes of dedicated lanes for autonomous vehicles (AVs) considering the changes of urban spatial structure in a closed city, where AVs and regular vehicles (RVs) coexist. An urban spatial equilibrium model for a monocentric and circular city is formulated, in which the travel and residential location choice are interdependent, considering the variable road capacity and reduced value of travel time brought by AVs. The theoretical boundary for the AV proportion in flow with the positive and negative influence of dedicated AV lanes on traffic efficiency are given. Then, the optimized placement of dedicated lanes for AVs, with and without consideration of residential relocation, are examined. First, the short-term effects of a dedicated AV lane are examined under a fixed residential distribution, with the objective of minimizing total travel time. The results indicate that a dedicated AV lane improves traffic efficiency only when the market penetration rate (MPR) of AVs is at a moderate level. Second, the long-term effects of a dedicated AV lane are considered, allowing for changes in residential location choices. In this case, the design objective is to maximize social welfare, and the optimal solution requires a shorter dedicated AV lane compared to the short-term scenario. The findings reveal the opposite spatial changes, that is, dedicated AV lanes encourage AV users to relocate farther from the city center, while RV users tend to move closer. Furthermore, neglecting the long-term relocation behavior of residents leads to inaccurate travel time estimates and excessive infrastructure investments
Curriculum development for Postgraduate UK Veterinary General Practice Training:A rapid review and documentary analysis
No full textPatient and center factors in home dialysis therapy uptake: analysis of a UK renal registry cohort and a National Dialysis Center survey
No full textRATIONALE & OBJECTIVE: Variation in home dialysis therapy (HT) use across centers and geography may reflect the interplay between dialysis center services and patient characteristics. We examined direct and indirect associations between these factors and HT uptake in England.
STUDY DESIGN: UK Renal Registry (UKRR) cohort linked to a national survey of renal centers.
SETTING & PARTICIPANTS: Adults who initiated kidney replacement therapy (KRT) between 2015 and 2019 at 51 English renal centers, totalling 32,400 individuals identified through the UKRR, with center practices captured from a 2022 national survey of dialysis centers.
EXPOSURES: Patient- (demographics and clinical characteristics) and center-level (including availability of assisted peritoneal dialysis, quality improvement initiatives, and fostering staff engagement in research) factors. OUTCOMES: Use of HT (home haemodialysis or peritoneal dialysis) within one year of starting KRT.
ANALYTICAL APPROACH: Sequences of regressions, an extension of path analysis, used to examine direct and indirect associations between patient- and center-level factors and the probability of HT uptake. RESULTS: Both center- and patient-level factors were significantly associated with the probability of HT uptake. Patients at centers conducting quality improvement projects, (OR [95% CI]) 1.94, [1.36-2.76]), offering assisted PD (1.89, [1.39-2.57]), fostering staff research engagement (1.35, [1.03-1.77]) or hosting HT roadshows (1.22, [1.05-1.41]) had higher odds of HT uptake. Centers with greater stress on staff capacity to deliver HT had lower uptake (0.60, [0.45-0.81]). Patients on transplant lists at KRT start (2.55, [2.35-2.77]) or who lived farther from a treatment center (1.10, [1.08-1.12] per 10km) had higher odds of HT uptake. Patients living in areas of higher deprivation or members of minority ethnic groups had lower HT uptake overall. However, some of these associations may have been indirectly mitigated in centers serving more diverse populations, as these centers were more likely to implement practices associated with higher HT uptake.
LIMITATIONS: Healthcare professional-reported and aggregated survey data.
CONCLUSIONS: This study identified modifiable center-level factors associated with HT uptake, informing potential opportunities to reduce ethnic and area-level disparities
Nurse-Led Hospital Violence Intervention Programmes Improve Emergency Department Identification of Violence-Related Visits
No full textLeveraging structural complexity to enable a lean supply base
No full textThe Zero Carbon Humber (ZCH) project, formed to create the UK’s largest decarbonised industrial cluster, requires a robust and lean supply base, which must meet the complex requirements for building a blue hydrogen production plant, including Carbon Capture & Storage (CCS). This study addresses the theoretical challenges of optimising supplier selection within a complex, dependency-prone network. The research examines the structural complexity of the supply base network, to assess dependency risks and inform decision makers of the ideal configuration of suppliers. Findings reveal areas of high dependency on certain suppliers for critical components, highlighting the need to expand the supply base. Furthermore, the study suggests that a carefully managed supplier network can balance lean efficiency with robustness, supporting the scalability required for the ZCH project’s long-term sustainability. The insights offer practical implications for policymakers and supply chain managers aiming to mitigate risks within complex industrial ecosystems
The index in d-exact categories
No full textStarting from its original definition in module categories with respect to projective modules, the index has played an important role in various aspects of homological algebra, categorification of cluster algebras and K-theory. In the last few years, the notion of index has been generalised to several different contexts in (higher) homological algebra, typically with respect to a (higher) cluster-tilting subcategory X of the relevant ambient category C. The recent tools of extriangulated and higher-exangulated categories have permitted some conditions on the subcategory X to be relaxed. In this paper, we introduce the index with respect to a generating, contravariantly finite subcategory of a d-exact category that has d-kernels. We show that our index has the important property of being additive on d-exact sequences up to an error term
The 3d Mixed BF Lagrangian 1-Form: A Variational Formulation of Hitchin’s Integrable System
No full textWe introduce the concept of gauged Lagrangian 1-forms, extending the notion of Lagrangian 1-forms to the setting of gauge theories. This general formalism is applied to a natural geometric Lagrangian 1-form on the cotangent bundle of the space of holomorphic structures on a smooth principal G-bundle P over a compact Riemann surface C of arbitrary genus g, with or without marked points, in order to gauge the symmetry group of smooth bundle automorphisms of P. The resulting construction yields a multiform version of the 3d mixed BF action with so-called type A and B defects, providing a variational formulation of Hitchin’s completely integrable system over C. By passing to holomorphic local trivialisations and going partially on-shell, we obtain a unifying action for a hierarchy of Lax equations describing the Hitchin system in terms of meromorphic Lax matrices. The cases of genus 0 and 1 with marked points are treated in greater detail, producing explicit Lagrangian 1-forms for the rational Gaudin hierarchy and the elliptic Gaudin hierarchy, respectively, with the elliptic spin Calogero–Moser hierarchy arising as a special subcase