260851 research outputs found
Sort by
On moments of the derivative of CUE characteristic polynomials and the Riemann zeta function
No full textWe study the derivative of the characteristic polynomial of Haar distributed unitary matrices. We obtain new explicit formulae for complex-valued moments when the spectral variable is inside the unit disc, in the limit . These formulae are expressed in terms of the confluent hypergeometric function of the first kind. We explore the connection between these moments and those of the derivative of the Riemann zeta function away from the critical line. Under the Lindel\"of hypothesis, we prove that all positive integer moments agree with our random matrix results up to a well-known arithmetic factor. Inspired by this finding, we propose a conjecture on the asymptotics of non-integer moments of the derivative of the Riemann zeta function off the critical line. Within random matrix theory, we also investigate the microscopic regime where the spectral variable satisfies for a fixed constant . We obtain an asymptotic formula for the moments in this regime as a determinant involving the finite temperature Bessel kernel, which reduces to the Bessel kernel when .</p
Second victim syndrome in surgeons: systematic review and meta-analysis of the impact of adverse events on surgeons
No full textBACKGROUND: Second victim syndrome (SVS) is characterized by negative psychological and psychosomatic effects on a healthcare provider after an adverse care event. The aim of this systematic review and meta-analysis was to characterize the symptoms of SVS experienced by surgeons and factors affecting their impact, as well as understand common coping strategies that surgeons employ to deal with them. METHODS: A systematic review of five electronic databases was conducted without restrictions on publication date or language in January 2025. Second victim syndrome, surgeon, and adverse event and their synonyms were used as search terms. Records were screened, quality assessed, and data extracted by two independent researchers. Both qualitative and quantitative studies were included and narratively synthesized. A meta-analysis was performed using a random effects model to calculate the overall prevalence rates of symptoms and coping methods. RESULTS: A total of 36 papers were included in the analysis from 6629 retrieved records. Anxiety (56.3% (95% c.i. 45.8% to 66.3%)), guilt (53.8% (95% c.i. 41.3% to 65.8%)), sadness (48.3% (95% c.i. 34.6% to 62.3%)), and sleep disturbance (50.5% (95% c.i. 38.4% to 62.5%)) were the most commonly reported symptoms. Talking to either colleagues (72.5% (95% c.i. 65.6% to 78.4%)) or family/friends (52.0% (95% c.i. 40.6% to 63.2%)) were the most commonly employed coping strategies. The sex and level of experience of the surgeon and the severity of the event were identified as potential predictors of deleterious impact. CONCLUSION: SVS significantly impacts surgeons' global well-being, leading to burnout and attrition. Effective interventions require a multifaceted approach, including peer support, resilience training, and institutional changes that normalize emotional responses, encourage disclosure, and address barriers to seeking help. Targeted support for at-risk groups may also be necessary.</p
Concreteness fading for primary school computing
No full textConcrete representations, such as visualisations or physical manipulatives, have a long history of use in the computing classroom. With the recent growth of interest in computational thinking, concrete representations have enabled children to understand concepts that, in abstract form, may otherwise be considered too advanced. Introducing children to computing concepts in a concrete way may be more engaging, and necessary at younger ages, but there is little evidence on effective methods for progressing from this towards abstract understanding. One approach, often used in mathematics, is Bruner’s Modes of Representation (Bruner, 1966), which suggests transitioning through enactive (concrete), iconic (pictorial), and symbolic (abstract) stages. Fyfe’s Theoretical Model of Concreteness Fading (TMCF) (Fyfe et al., 2014) extends the Modes of Representation to include more detailed design guidelines and hypotheses.This thesis empirically validates three of these hypotheses in the context of teaching introductory topics in computer networks and explores how the findings can be applied in the design of technology-enhanced learning environments. All experiments used a between-groups, pre-test / post-test design, and were conducted in a primary school in the South of England with children aged nine to ten.Experiment one (Trory et al., 2018) investigated the effect of representation type and sequence. Four groups were compared: Abstract, Concrete, Concreteness Fading (concrete → intermediate → abstract), and Concreteness Introduction (abstract → intermediate → concrete). The results showed a statistically significant main effect, with an ordering of groups that replicated Fyfe's findings. This supports the foundational guideline of the TMCF and demonstrates that it can be applied to primary computing education.Experiment two (Trory, Howland, Good, & D. du Boulay, 2024) investigated the effect of the physicality of the concrete representation. Two groups were compared: Physical Concrete and Virtual Concrete (implemented in an augmented reality tablet application). The results showed no statistically significant difference between the two groups, contrary to the guidelines of the TMCF. Given this lack of evidence regarding the benefit of physicality, and the potential practical and pedagogical benefits of a virtual environment, the final study focussed on investigating a third hypothesis in a virtual context.Experiment three (Trory, Howland, Good, & B. du Boulay, 2024) investigated the effect of a more gradual fade through an increased number of intermediate representations. Three groups were compared: Two-Step (concrete → concrete → abstract), Three-Step (concrete → intermediate → abstract), and Five-Step (concrete → concrete/intermediate → intermediate → intermediate/abstract → abstract). The results showed a statistically significant difference between the Two-Step and Three-Step groups in favour of the Three-Step, which confirms the value of explicitly linking mutual referents when moving from concrete to abstract representations. No statistically significant difference was found between the Three-Step and Five-Step groups.This thesis provides evidence that the TMCF guidelines regarding sequence order and the use of explicitly linking mutual reference apply in primary computing and demonstrate the potential for implementing fading in virtual environments, as well as highlighting further key questions for investigation.</p
Large-scale, mixed-precision brain simulations on heterogeneous accelerators
No full textIn order to maximise the performance of scientific computing applications on modern heterogeneous systems, it is necessary to embrace reduced-precision arithmetic. Simulations of large networks of neurons are a vital tool for neuroscience, but are constrained by memory capacity and bandwidth. Here, we explore the use of half-precision arithmetic for brain simulations. We find that half-precision is sufficient for weight storage but not for simulating the dynamics of highly-connected cortical neurons. Nonetheless, just using half-precision weights almost halves the memory requirements of models and allows us to simulate a large model of the macaque visual cortex on a single AMD Instinct MI300X GPU 1.4× faster than on a 32-node CPU cluster.</p
Beyond geography, destiny, and politics: exploring policy styles for industrial decarbonisation in Norway, the United Arab Emirates and the United States
No full textThis paper examines industrial decarbonisation in Norway, the United Arab Emirates (UAE), and the United States using sectoral policy styles as a theoretical lens. These countries are major fossil fuel producers with significant renewable energy resources, technical expertise, and financial capabilities to implement decarbonisation, each also representing distinct political systems. It asks: What are the most salient features and instruments mobilised by policymakers and regulators in designing industrial decarbonisation policies in these countries? The study goes beyond notions of geography, destiny, and politics to closely analyse the coalescence of actors, institutions, and policy instruments shaping industrial decarbonisation in each country. While all three countries share similar ambitious climate targets, their policy styles and implementation approaches differ considerably. Norway's approach emphasises technological neutrality, carbon pricing, and collaborative policy development. The UAE's policy style is characterised by centralised decision-making, a strong emphasis on international engagement, and the leading role of government-owned anchor industries. The United States exhibits a more complex multi-level governance system, with significant variations across states, a reliance on market-based incentives, and a historically limited role for industrial planning. The findings suggest that national policy styles and regime characteristics strongly influence the implementation of industrial decarbonisation policies, despite the increasing convergence of policy formulation due to international agreements and the exchange of best practices. Acknowledging the persistent divergence in implementation due to unique national contexts and institutional settings contributes to a better understanding of the factors driving industrial decarbonisation and offers insights for effective policy design and implementation in different political and economic contexts.</p
On the throughput of RSMA-ALOHA for vortex wave communications
No full textIn this letter, we propose an uplink rate splitting multiple access (RSMA)-assisted slotted ALOHA (RSMA-ALOHA) for vortex wave (VW) communications, referred to as VW-RSMA-ALOHA. In VW-RSMA-ALOHA, we perform cross-layer optimization of the physical (PHY) and medium access control (MAC) layers by integrating RSMA-based orbital angular momentum (OAM) mode transmission with the slotted ALOHA protocol. Machine-type devices transmit packet as OAM mode using a single uniform circular array (UCA) antenna, while the access point receives all OAM modes from multiple users using concentric UCAs. Theoretical bounds are derived from VW-RSMA-ALOHA throughput, and the results demonstrate that this proposed method enhances the RA throughput in uplink VW communications.</p
Board composition, independence and gender diversity in corporate governance: Saudi Arabia and international best practices
No full textBoard gender diversity and board independence are key elements in board composition which have long been considered important topics in academic literature. Women are significantly underrepresented in Saudi corporate boards and their progress has been very slow, primarily because the government has not yet implemented any regulatory approaches to promote their participation on corporate boards. Furthermore, the Saudi Corporate Governance Regulations 2017 (SCGRs 2017) contains two main challenges related to board independence: the definition of independent directors and the required number of independent directors, both of which undermine their ability to effectively perform their roles of oversight and objective decision-making. This thesis aims to offer improvements and reforms to SCGRs 2017 to address the challenges of women's participation and board independence in Saudi corporate boards. The study addresses two research questions: To what extent do gender diversity and independence on boards contribute to effective corporate governance? What regulatory measures would be most suitable for Saudi Arabia to tackle issues concerning board gender diversity and board independence? This thesis argues that appropriate levels of board independence and women's participation on corporate boards are crucial to promote the interests of various stakeholders' groups. The research employs a doctrinal legal approach, supported by documentary analysis of secondary sources and a comparative analysis of Norwegian, the UK, and Malaysian jurisdictions. Drawing on Dhir's factors and the theory of legal transplant, this research provides valuable insights from the countries under analysis that can effectively address the challenges of board gender diversity and board independence in Saudi Arabia. This research contributes to the existing literature by offering a unique analysis of these challenges, which have not been sufficiently examined or addressed before.</p
Assessing quality of life in individuals with hereditary cancer risk: results from phases 1-3a of the EORTC QLQ-HCR30 questionnaire
No full textBackground: The aim of this study is to develop a European Organisation of Research and Treatment of Cancer (EORTC) patient-reported outcome measure (PROM) to assess quality of life (QOL) in individuals diagnosed with a hereditary cancer predisposition syndrome (HCPS) with or without a previous cancer diagnosis. We report on content generation, questionnaire construction, and questionnaire evaluation of acceptability, comprehensiveness, and linguistic validity.Methods: Following phase 1 to 3a of the EORTC Quality of Life Group module development guidelines, QOL issues were identified through a literature review and interviews with health-care professionals and individuals undergoing HCPS genetic counseling or testing. Based upon the results, a preliminary questionnaire was developed and pre-tested internationally for relevance, clarity, and linguistic appropriateness. Revisions were guided by qualitative feedback and predefined criteria.Results: 63 issues were identified from the literature and expanded to a 73-item questionnaire through interviews. Pre-testing of the questionnaire in 119 individuals (79.8% female) across twelve centers in nine countries, including carriers of BRCA, Lynch syndrome, and Li-Fraumeni, showed limited applicability for those with negative or pending results. The target population was therefore refined to mutation carriers. Following item reduction, the final instrument comprised thirty validated and linguistically appropriate items.Conclusion: The EORTC QLQ-HCR30 is relevant and applicable for assessing QOL in individuals diagnosed with a HCPS and is now ready for preliminary psychometric evaluation (phase 3b and 4).</p
The nose knows: thermal responses to active psychological stressors
No full textStress is an essential component of our lives. It helps to us to keep alert, stay motivated, and adapt to new and challenging situations. However, it is also a leading cause of poor mental wellbeing. Investigating psychological stress is essential to improving both the physical and mental health of the general population. Current methods often rely on self-report and physically invasive (contact) measures which can lack objectivity and ecological validity. Thermal imaging is emerging as a powerful objective, continuous, and physically non-invasive (non-contact) tool to investigate psychological stress through changes in nasal skin temperature. Yet there remain gaps in our understanding of thermal ranges, thermal recovery, and thermal associations with perceived stress in the healthy population. We present a new protocol, employing continuous thermal video to measure nasal temperature fluctuations during stress induction in healthy adults. Results indicate that induced psychological stress significantly decreases nasal temperature compared with a white noise baseline, and a social stress task elicited a significantly stronger nasal temperature decrease from baseline compared with a cognitive stress task. Although perceived stress was not associated with nasal thermal fluctuations, perceived somatic anxiety symptoms did significantly relate with nasal temperature change. These findings reveal new insight into the psychological and physiological human stress experience. The continuous, non-contact and objective benefits of thermal imaging makes it uniquely placed to contribute to real-world health applications, including translation to clinical and nonverbal populations across the lifespan.</p
Prediction of joint moment in lower limbs based on deep learning and multimodal data
No full textThis study aimed to predict the moments at the hip, knee, and ankle joints in multiple planes during various movements. A deep learning model was developed using a bidirectional long short-term memory network (BiLSTM) combined with an agent attention mechanism (AA). Multimodal data were collected from 20 young subjects, including anthropometric data, joint angles, electromyographic signals, and ground reaction forces. The corresponding joint moments were calculated using Anybody motion simulation software. These data were used as input to the BiLSTM-AA model for joint moment prediction. Different input combinations and dimensionality reduction methods were compared. The best results were obtained by integrating anthropometric data, joint angles, and ground reaction forces. In cross-subject tests, the model showed high accuracy, with a mean absolute error of 0.0395 Nm/kg, root mean square error of 0.0579 Nm/kg, and a coefficient of determination of 0.9117. The model also performed well after reducing input dimensions. In summary, the BiLSTM-AA model predicts lower limb joint moments accurately across activities. This may simplify real-world data collection and help provide solid evidence for rehabilitation planning and assessment.</p