Showing papers by "University of Nottingham published in 2023"

Next generation neural population models

Abstract: Low-dimensional neural mass models are often invoked to model the coarse-grained activity of large populations of neurons and synapses and have been used to help understand the coordination of large scale brain rhythms. However, they are phenomenological in nature and, although motivated by neurobiological considerations, the absence of a direct link to an underlying biophysical reality is a weakness that means they may not be best suited to capturing some of the rich behaviors seen in real neuronal tissue. In this perspective article I discuss a simple spiking neuron network model that has recently been shown to admit to an exact mean-field description for synaptic interactions. This has many of the features of a neural mass model coupled to an additional dynamical equation that describes the evolution of population synchrony. This next generation neural mass model is ideally suited to understanding the patterns of brain activity that are ubiquitously seen in neuroimaging recordings. Here I review the mean-field equations, the way in which population synchrony, firing rate, and average voltage are intertwined, together with their application in large scale brain modeling. As well as natural extensions of this new approach to modeling the dynamics of neuronal populations I discuss some of the open mathematical challenges in developing a statistical neurodynamics that can generalize the one discussed here.

Inferring the basis of binaural detection with a modified autoencoder

Abstract: The binaural system utilizes interaural timing cues to improve the detection of auditory signals presented in noise. In humans, the binaural mechanisms underlying this phenomenon cannot be directly measured and hence remain contentious. As an alternative, we trained modified autoencoder networks to mimic human-like behavior in a binaural detection task. The autoencoder architecture emphasizes interpretability and, hence, we "opened it up" to see if it could infer latent mechanisms underlying binaural detection. We found that the optimal networks automatically developed artificial neurons with sensitivity to timing cues and with dynamics consistent with a cross-correlation mechanism. These computations were similar to neural dynamics reported in animal models. That these computations emerged to account for human hearing attests to their generality as a solution for binaural signal detection. This study examines the utility of explanatory-driven neural network models and how they may be used to infer mechanisms of audition.

A maturity model for the autonomy of manufacturing systems

Abstract: Abstract Modern manufacturing has to cope with dynamic and changing circumstances. Market fluctuations, the effects caused by unpredictable material shortages, highly variable product demand, and worker availability all require system robustness, flexibility, and resilience. To adapt to these new requirements, manufacturers should consider investigating, investing in, and implementing system autonomy. Autonomy is being adopted in multiple industrial contexts, but divergences arise when formalizing the concept of autonomous systems. To develop an implementation of autonomous manufacturing systems, it is essential to specify what autonomy means, how autonomous manufacturing systems are different from other autonomous systems, and how autonomous manufacturing systems are identified and achieved through the main features and enabling technologies. With a comprehensive literature review, this paper provides a definition of autonomy in the manufacturing context, infers the features of autonomy from different engineering domains, and presents a five-level model of autonomy — associated with maturity levels for the features — to ensure the complete identification and evaluation of autonomous manufacturing systems. The paper also presents the evaluation of a real autonomous system that serves as a use-case and a validation of the model.

“The many faces of sorrow”: An empirical exploration of the psychological plurality of sadness

Abstract: Sadness has typically been associated with failure, defeat and loss, but it has also been suggested that sadness facilitates positive and restructuring emotional changes. This suggests that sadness is a multi-faceted emotion. This supports the idea that there might in fact be different facets of sadness that can be distinguished psychologically and physiologically. In the current set of studies, we explored this hypothesis. In a first stage, participants were asked to select sad emotional faces and scene stimuli either characterized or not by a key suggested sadness-related characteristic: loneliness or melancholy or misery or bereavement or despair. In a second stage, another set of participants was presented with the selected emotional faces and scene stimuli. They were assessed for differences in emotional, physiological and facial-expressive responses. The results showed that sad faces involving melancholy, misery, bereavement and despair were experienced as conferring dissociable physiological characteristics. Critical findings, in a final exploratory design, in a third stage, showed that a new set of participants could match emotional scenes to emotional faces with the same sadness-related characteristic with close to perfect precision performance. These findings suggest that melancholy, misery, bereavement and despair can be distinguishable emotional states associated with sadness.

Helminth parasites of the wood mouse <i>Apodemus sylvaticus</i> in Southern England: levels of infection, species richness and interactions between species

Abstract: Helminth parasites of the wood mouse, Apodemus sylvaticus (n = 440), were surveyed in five localities, comprising woodland and grassland sites, in Southern England. Seven species of helminths were identified, among which Heligmosomoides polygyrus and Syphacia stroma were dominant (prevalence = 79.1% and 54.1%, respectively). Less common species were the trematode Corrigia vitta (14.8%), cestodes Catenotaenia pusilla (8.4%), Hydatigera taeniaeformis (4.1%) and Microsomacanthus crenata (3.4%) and the nematode Aonchotheca murissylvatici (0.2%). Differences in prevalences between localities were found for H. polygyrus, H. taeniaeformis and M. crenata and in abundances of H. polygyrus, S. stroma and C. vitta. Age-dependent increases in both parameters were identified among species and for helminth species richness. The only species to show significant host sex bias was S. stroma with prevalence values being higher in male mice. A number of different methods for exploiting raw data, and data corrected for significant confounding factors, were used to determine whether there were significant associations (prevalence) between species or quantitative interactions (abundance). The strongest evidence for a positive association was shown in concurrent infections with the trematode C. vitta and the cestode C. pusilla (significant in the whole dataset and evident in each locality, both sexes and both age classes). The abundance of C. pusilla was also higher in mice with C. vitta and vice versa. Overall, however, there was little support for associations or quantitative interactions between species, especially after data had been corrected for significant extrinsic/intrinsic factors, and we conclude that the helminths of wood mice in these communities are largely non-interactive and hence, perhaps better referred to as assemblages.

Resolution of sustained ventricular tachycardia in a horse presenting with colic with magnesium sulfate

Abstract: Case reports demonstrating a return to sinus rhythm from sustained ventricular tachycardia (VT) are limited. VT is uncommon in horses but can be life threatening and has been reported in horses with primary gastrointestinal disease. Treatment is recommended if there is poor perfusion, if heart rate exceeds 100 beats/min, if multiform/polymorphic complexes or torsades des pointes is present. Lidocaine or magnesium sulfate is the first-line medication. In this case, a 19-year-old Warmblood gelding with a history of exploratory laparotomy presented with an irregularly irregular cardiac rhythm and heart rate of 80 beats/min. ECG demonstrated VT with a heart rate of 75 beats/min. As the horse was already receiving a lidocaine bolus, the VT was treated with multiple boluses of intravenous magnesium sulfate over a period of several hours. This converted the VT to normal sinus rhythm (NSR) with heart rate of 44 beats/min and the horse remained in NSR until discharge 8 days later.

The impact of a revision arthroplasty network on patient outcomes

Abstract: Revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA) are complex procedures with higher rates of re-revision, complications, and mortality compared to primary TKA and THA. We report the effects of the establishment of a revision arthroplasty network (the East Midlands Specialist Orthopaedic Network; EMSON) on outcomes of rTKA and rTHA.The revision arthroplasty network was established in January 2015 and covered five hospitals in the Nottinghamshire and Lincolnshire areas of the East Midlands of England. This comprises a collaborative weekly multidisciplinary meeting where upcoming rTKA and rTHA procedures are discussed, and a plan agreed. Using the Hospital Episode Statistics database, revision procedures carried out between April 2011 and March 2018 (allowing two-year follow-up) from the five network hospitals were compared to all other hospitals in England. Age, sex, and mean Hospital Frailty Risk scores were used as covariates. The primary outcome was re-revision surgery within one year of the index revision. Secondary outcomes were re-revision surgery within two years, any complication within one and two years, and median length of hospital stay.A total of 57,621 rTHA and 33,828 rTKA procedures were performed across England, of which 1,485 (2.6%) and 1,028 (3.0%), respectively, were conducted within the network. Re-revision rates within one year for rTHA were 7.3% and 6.0%, and for rTKA were 11.6% and 7.4% pre- and postintervention, respectively, within the network. This compares to a pre-to-post change from 7.4% to 6.8% for rTHA and from 11.7% to 9.7% for rTKA for the rest of England. In comparative interrupted time-series analysis for rTKA there was a significant immediate improvement in one-year re-revision rates for the revision network compared to the rest of England (p = 0.024), but no significant change for rTHA (p = 0.504). For the secondary outcomes studied, there was a significant improvement in trend for one- and two-year complication rates for rTHA for the revision network compared to the rest of England.Re-revision rates for rTKA and complication rates for rTHA improved significantly at one and two years with the introduction of a revision arthroplasty network, when compared to the rest of England. Most of the outcomes studied improved to a greater extent in the network hospitals compared to the rest of England when comparing the pre- and postintervention periods.

A Qualitative Study on the Experiences of Therapists Delivering the Promoting Activity, Independence and Stability in Early Dementia (PrAISED) Intervention During the COVID-19 Pandemic

Abstract: The Promoting Activity, Independence and Stability in Early Dementia (PrAISED) intervention is a programme of physical activity and exercise designed to maintain participation in activities of daily living, mobility, and quality of life for people living with dementia. During the COVID-19 pandemic first national lockdown in England, the PrAISED physiotherapists, occupational therapists, and rehabilitation support workers adapted to delivering the intervention remotely via telephone or video conferencing.The aim of this study was to explore therapists' experience of delivering the PrAISED intervention during the COVID-19 pandemic and derive implications for clinical practice.Qualitative semi-structured interviews were conducted with 16 therapists using purposive sampling. Thematic analysis was used to analyze the transcripts.Therapists reported a change in the relationship between themselves, the person with dementia and the caregiver, with an increased reliance on the caregiver and a loss of autonomy for the person living with dementia. There was concern that this would increase the burden on the caregiver. The therapists reported using creativity to adapt to different modes of delivery. They felt their sessions were mostly focused on providing social and emotional support, and that assessing, progressing, and tailoring the intervention was difficult.It is possible to deliver some elements of a physical intervention using remote delivery, but a dual modal approach including remote and face-to-face delivery would optimize treatment efficacy. Educational support would be required to enable people living with dementia and their caregivers to overcome barriers relating to digital literacy.

The Use of Gendered Chatbots in Nigeria: Critical Perspectives

Abstract: Abstract In a bid to improve service delivery and efficiency in Nigeria, the use of conversational agents such as chatbots capable of providing round the clock responses is growing. This is gaining more traction in the financial sector, particularly in fintechs where there have been significant improvements in the last year. However, not enough research has been conducted on the impact of the gendering of these conversational agents. This is concerning, especially as findings from our research reveal that the majority of chatbots currently deployed in the country are deliberately gendered to appear female, reinforcing already existing gender stereotypes within African societies. With an increase in the deployment of these bots in many other sectors, it is crucial to evaluate the significance of the gendering of these bots to ascertain the effect on gender inequality in Nigeria.

Predicting bioactivity of antibiotic metabolites by molecular docking and dynamics

Abstract: Antibiotics enter the environment through waste streams, where they can exert selective pressure for antimicrobial resistance in bacteria. However, many antibiotics are excreted as partly metabolized forms, or can be subject to partial breakdown in wastewater treatment, soil, or through natural processes in the environment. If a metabolite is bioactive, even at sub-lethal levels, and also stable in the environment, then it could provide selection pressure for resistance. (5S)-penicilloic acid of piperacillin has previously been found complexed to the binding pocket of penicillin binding protein 3 (PBP3) of Pseudomonas aeruginosa. Here, we predicted the affinities of all potentially relevant antibiotic metabolites of ten different penicillins to that target protein, using molecular docking and molecular dynamics simulations. Docking predicts that, in addition to penicilloic acid, pseudopenicillin derivatives of these penicillins, as well as 6-aminopenicillanic acid (6APA), could also bind to this target. MD simulations further confirmed that (5R)-pseudopenicillin and 6APA bind the target protein, in addition to (5S)-penicilloic acid. Thus, it is possible that these metabolites are bioactive, and, if stable in the environment, could be contaminants selective for antibiotic resistance. This could have considerable significance for environmental surveillance for antibiotics as a means to reduce antimicrobial resistance, because targeted mass spectrometry could be required for relevant metabolites as well as the native antibiotics.

Gauss-Bonnet Curvature Corrections and the Absence of de Sitter Vacua

Abstract: In the previous chapter, we described a number of phenomenological impediments to quintessence model building. Many of the arguments we described rely on compactifications of string theory on Calabi-Yau manifolds, originally chosen to preserve some supersymmetry in the external space.

Association between serologically confirmed COVID-19 infection and cognitive functioning in community dwelling older adults

Abstract: COVID-19 infection can impact the central nervous system, and is often associated with cognitive decline. However, there are no studies linking serologically confirmed COVID-19 infection with objectively assessed cognitive functioning. We explored whether presence of SARS-CoV-2 antibodies account for variability in participants' scores on a neuropsychological assessment.In this cross-sectional study participants were 657 (mean age = 72.97; SD = 6.07 years; women = 47.7%) individuals randomly selected from the general population of the canton of Zurich and included in the Corona Immunitas study. We conducted serological tests between October 2020 and May 2021 to detect and quantify SARS-CoV-2 antibodies in peripheral venous blood samples. We assessed cognitive function, vaccination status (vaccinated; not vaccinated), number of health conditions, and demographic variables between January and August 2021. We studied the association between seropositivity and global cognitive function and five cognitive domains (language expression, language comprehension, temporal orientation, spatial orientation, and memory) with linear regression models. Based on SARS-CoV-2 antibodies and vaccination status, we stratified participants into three groups: No SARS-CoV-2 antibodies (N = 402); SARS-CoV-2 antibodies due to vaccination (N = 218); history of SARS-CoV-2 infection and no vaccination (N = 37).In the regression model adjusted for age, sex, educational level, and number of health conditions, compared to those without SARS-CoV-2 antibodies, those with SARS-CoV-2 antibodies due to vaccination had better global cognitive functioning (Standardized beta = 0.10; 95% CI = 0.02; 0.17), and those with SARS-CoV-2 antibodies due to infection had poorer cognitive functioning (Standardized beta = -0.10; 95% CI = -0.18; -0.03). Regarding cognitive domains, compared to those without SARS-CoV-2 antibodies, those with SARS-CoV-2 antibodies due to infection scored more poorly on language comprehension and temporal orientation, and those with SARS-CoV-2 antibodies due to vaccination scored better on memory.By linking serologically confirmed presence of SARS-CoV-2 antibodies to poorer global cognitive functioning in community dwelling older adults we strengthen existing evidence in support of cognitive decline related to COVID-19. Given the large number of infected older adults, and the endurance of the pandemic, our results highlight the need to address COVID-19 related cognitive decline in the clinical and public health areas of prevention, diagnosis, and treatment.

Teachers willingness and ability to teach to their best and well: the person in the professional

Abstract: Over the years, there has been a growing acknowledgment of the complex factors and contexts which teachers must navigate over a career if they are to learn, develop, and sustain “good” teaching. Researchers have focused variously upon the influence of biography, identity, policy, culture, organization, leadership, and moral purpose on teachers' beliefs, purposes and practices. This article will seek to bring these strands together in order to discuss their effects, and how the extent to which they are managed by teachers and their school leaders influences their willingness and ability to teach to their best and well.

Intermezzo: Supergravity and the Swampland

Abstract: AbstractIn the first half of this thesis, we have discussed stringy motivated models and EFTs without making explicit a UV completion. For a consistent EFT treatment, this has the benefit of allowing for concrete and analytical treatment of the four-dimensional low-energy effective field theory by decoupling the microphysics of gravity.

Incivility from the UK Prime Minister’s Dispatch Box: A Comparative Study of PM Question Time Attacks, 2010–2020

Abstract: Despite the widespread notion that political incivility is on the rise, including the British Parliament, there is scarce research that systematically examines political incivility over time within and outside of the British context. As such, this chapter presents a rare longitudinal study of adversarial communication in the British Parliament. We explore the extent to which Prime Ministers (PMs) and Members of Parliament (MPs) used trait attacks and uncivil attacks during Prime Minister Questions (PMQs) in the period between 2010 and 2020. Our results show that despite the official ban on unparliamentary language, PMQs are filled with adversarial communication, including uncivil discourse. While we do not identify a linear increase in political incivility, we do find that the use of uncivil attacks fluctuates and becomes more frequent when elections draw closer. Furthermore, we uncover vast differences among PMs. Former Prime Minister Boris Johnson used most trait and uncivil attacks, while former Prime Minster Theresa May employed the fewest uncivil attacks of all prime ministers. The results contribute to academic research on political incivility and the broader debate on the communication style of political leaders, especially in British politics and more particularly, during PMQs.

Introduction to power electronics

Abstract: This section introduces the article on power electronics. It firstly describes why power electronic convertors are required, and then provides a brief overview of what power electronic devices are and how they are used. It then describes the constraints associated with power electronic switches which determine the system design and operating conditions. The application areas for power converters are then presented, together with the challenges introduced by their use, and the opportunities for development and improvement of these systems. As such the introduction provides a brief overview of the more detailed discussions provided in the rest of the article.

Institutions and tax capacity in sub-Saharan Africa

Abstract: Abstract This paper contributes to research on the institutional determinants of tax capacity using annual data from 39 sub-Saharan African countries from 1985 to 2018 to construct a measure of tax capacity for each country based on the trend component of the ratio of actual to potential tax revenue. Potential revenue is estimated by a parsimonious tax performance specification, including only variables found to be robust determinants of the tax/GDP ratio. The results show that, on average, tax capacity is high (given potential) and has improved over time (especially for low-income countries). The final stage of analysis selects, from a wide variety of economic and institutional variables, the most important determinants of cross-country variation in tax capacity. Equal distribution of resources is the most important institutional factor associated with greater capacity, consistent with perceptions of equity supporting the fiscal bargain; corruption is associated with lower capacity, consistent with undermining trust in government. Private consumption and resource rents are associated with greater capacity. Other institutional factors are indirectly associated with greater capacity, such as accountability and elements of democracy associated with equity in the allocation and use of public resources.