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Data-driven stochastic model updating and damage detection with deep generative model
No full textIs there a calibration algorithm beyond the dominant Bayesian sampling approach and sensitivity-based optimisation in model updating? Can a neural network serve not only as a surrogate model but also possess its own calibration capacity, independent of the Bayesian or optimisation framework? This work aims to address these questions by developing a unique data-driven approach for stochastic model updating and damage detection. Among a variety of models in deep learning, the class of deep generative model shares a similar objective, to estimate an unknown or intractable probability distribution from a small number of samples, with model updating. As a powerful flow-based deep generative model, a recently developed conditional Invertible Neural Network (cINN) architecture has been adopted in the task of model updating. Unlike the conventional approaches that employ the neural networks solely as a forward surrogate, the cINN-based model updating is a framework that performs as a bidirectional network where the forward training and inverse calibration are integrated into a uniform structure. The cINN consists of two parts known as the conditional network and the invertible neural network (INN). Both networks are trained jointly in the forward direction and can operate inversely to offer rapid and accurate predictions by given observation data. The application of the cINN provides a more efficient and direct manner to solve model updating problems without calculating the likelihood function in Bayesian inference. The cINN is embedded into a multilevel stochastic updating framework. Rather than directly calibrating physical parameters, this multilevel framework focuses on their statistical moments, e.g. mean and variance, referred to as hyperparameters. The hyperparameters are then utilised to determine the probability of damage (PoD), which provides a confidence level about the structural condition, facilitating stochastic damage detection. Two case studies are proposed to demonstrate the multilevel cINN-based stochastic updating and damage detection approach. The first involves a 3-degree-of-freedom spring-mass simulation model, while the second case study employs an experimental rig testcase with practical measurements, each under various damage scenarios
Mechanistic understanding of the relationship between oxidative and electrophilic stress in allergic skin sensitisation
No full textAllergic skin sensitisation manifests clinically as allergic contact dermatitis (ACD), an inflammatory disease of the skin that affects roughly 20% of the European population. ACD is caused by a delayed immune response to skin proteins modified by small molecule electrophiles, sensitisers. Oxidative and electrophilic stress are series of complex cellular responses to normal physiological and pathophysiological processes. Accumulation of reactive oxygen species (ROS) causes the generation of reactive electrophiles that can bind proteins, lipids. Cells possess antioxidant mechanisms such as glutathione (GSH) that scavenge, bind, and render ROS and electrophiles inert.Antioxidant response element gene activation is a key event in allergic skin sensitisation. Additionally, GSH has been shown to bind and eliminate model skin sensitisers including 2,4-dinitrochlorobenzene (DNCB). The mechanisms of the role(s) of oxidative stress in sensitisation are incompletely characterised. Using proteomics methods with in vitro HaCaT human keratinocytes, this project aims to improve our understanding of the role(s) of oxidative stress in allergic skin sensitisation. Data suggests that ROS induced oxidative stress leads to increased activity of catalase, inhibition of superoxide dismutase, and depletion of GSH following exposure to the sensitiser DNCB. However, protein signalling pathways that could increase generation of ROS and potentially leave keratinocytes vulnerable to increased oxidative and electrophilic damage following DNCB exposure do not appear to be significantly altered by a pre-existing state of ROS induced oxidative stress
<i>S-</i>to<i>-P</i> receiver function imaging of lithospheric discontinuities in New Zealand at the Hikurangi subduction zone
No full textSubduction zones are important regions for understanding plate tectonic processes. New Zealand experiences slow slip, volcanism, and back-arc rifting, and has evidence of large megathrust events and tsunamis. We use S-to-P receiver functions to image lithospheric discontinuities beneath the North Island of New Zealand. A positive discontinuity interpreted as the Moho is imaged at 15–30 ± 3 km depth beneath the overriding Australian Plate. In some locations, near the interface of the Pacific and Australian Plates, we don't image the Pacific Plate Moho, and the Australian Plate Moho is faint or absent. The former could be related to the increasing dip or eclogitization of the Pacific Plate crust, and the latter is likely related to mantle wedge serpentinization. A negative velocity discontinuity associated with the lithosphere-asthenosphere boundary (LAB) of the Australian Plate is imaged at 63–80 ± 8 km depth across the northwestern side of the island. Negative discontinuities are imaged beneath the southern Pacific Plate at 85–105 ± 10 km and 130 ± 13 km depth, representing either a mid-lithospheric discontinuity (MLD) and a deeper LAB, or more likely a shallow LAB and a deeper artifact, given that the latter is better aligned with previous work. Beneath the Australian Plate, asthenospheric melt is inferred in the northwest beneath several regions of active volcanism. Beneath the Pacific Plate, asthenospheric melt is inferred near the trench, also corresponding to the transition to where the plates become locked; therefore, plate locking could be related to the buoyancy of the melt.</p
Evaluation of activity and function before and immediately after the provision of a microprocessor knee in individuals with transfemoral amputation
No full textBACKGROUND: In many cases, individuals with lower limb amputation become less active because of impaired balance and stability and increased risk of falling. Microprocessor knees (MPKs) have been shown to reduce the risk of falls, improve balance, and increase function, evaluated with self-reported scales and questionnaires. This study aims at investigating whether the patient-reported improvements are reflected in objective physical activity (PA) parameters estimated from actimetry sensors and assess the short-term provision of an MPK.STUDY DESIGN: Transfemoral amputee patients (n=29) undertaking an MPK trial at 2 prosthetic centers in the South of England were recruited for this study. Self-reported and functional test outcomes (Activities Balance Confidence, Reintegration of Normal Living Index, Prosthesis Evaluation Questionnaire scores, and 2-min walk test) were obtained before and after (4 weeks) the provision of the MPK. Activity levels were recorded over 7 consecutive days pre- and post-MPK.RESULTS: Self-reported scores and function test outcomes showed a general improvement in most of the patients after the provision of the MPK, with a statistically significant change ( p < 0.05) in Activities Balance Confidence, Reintegration of Normal Living Index, Prosthesis Evaluation Questionnaire scores, and 2-min walk test. By contrast, the activity-based parameters estimated from actimetry showed no statistically significant changes ( p > 0.05). Associations between self-reported and functional outcomes and actimetry parameters were limited.CONCLUSIONS: Perceived and in-clinic outcome measures improved after short-term provision of an MPK for transfemoral amputees. However, PA did not change in this cohort of patients over the study period. More longitudinal studies are needed to characterize the impact of MPK provision on PA and societal participation.</p
<i>Property in Contemporary Capitalism</i> By PaddyIreland, Bristol: Bristol University Press, 2024, 310 pp., £19.99
No full textPaddy Ireland’s masterly exploration of the nature of property in contemporary capitalism argues that property is a major– and undertheorized– constituent of capitalism’s current crisis. For Ireland, property is inextricably linked to rising indebtedness, recurring economic crises, increasing inequality, environmental degradation, and the accelerating climate crisis. Urgent and fundamental reform of the property–capitalism nexus is vital, but property theory, stuck in a ‘new essentialism’, misunderstands contemporary property. Ireland observes that most property scholarship works from within an analytical jurisprudential tradition seeking universal truths about the transhistorical and transcultural essence of property. This approach, so remote from empirical realities, is woefully inadequate for telling a different story of property. If a new story is to emerge– and for Ireland it must, because property ownership, and consequentially power, is destructively concentrated in the hands of extremely wealthy individuals and corporations– then that story must be interdisciplinary, historically informed, and sufficiently eclectic to facilitate conceptualizations of property that highlight its contingency and malleability. This review is structured as follows. It begins by sketching out the contents of the book, highlighting the breadth of Ireland’s scholarship. It then responds to the book’s stated goal– to widen the conversation about property– by considering how property’s contemporary significance might be further explored. Theoretically, we ask what a more developed Polanyian perspective might add to Ireland’s analysis. Methodologically, we consider what might be required of an empirical approach to contemporary property problems. Finally, we consider the implications for the teaching of property law
Improved precision calculation of the 0νββ contact term within chiral effective field theory
No full textNeutrinoless double-beta (0νββ) decay is an as-yet unobserved nuclear process, which stands to provide crucial insights for model building beyond the Standard Model of particle physics. Its detection would simultaneously confirm the hypothesis that neutrinos are Majorana fermions, thus violating lepton-number conservation, and provide the first measurement of the absolute neutrino mass scale. This work aims to improve the estimation within chiral effective field theory of the so-called "contact term"for 0νββ decay, a short-range two-nucleon effect that is unaccounted for in traditional nuclear approaches to the process. We conduct a thorough review of the justifications for this contact term and the most precise computation of its size to date [gνNN=1.3(6) at renormalization point μ=mπ], whose precision is limited by a truncation to elastic intermediate hadronic states. We then perform an extension of this analysis to a subleading class of inelastic intermediate states that we characterize, delivering an updated figure for the contact coefficient [gνNN=1.4(3) at μ=mπ] with uncertainty reduced by half. Such ab initio nuclear results, especially with enhanced precision, show promise for the resolution of disagreements between estimates of 0ννββ from different many-body methods.</p
High-resolution mapping of residential wood burning heat sources using Energy Performance Certificates: a case study of England and Wales
No full textBackground: particulate matter emissions from residential wood burning are rising in many countries. Long-term exposure to fine particulate matter is strongly linked with adverse health effects including cardiovascular and respiratory disease. Policymakers and scientists need accurate tools to identify residential wood burning hotspot sat fine scale. However, current methods rely on spatially-misaligned, out-of-date data sources,reducing their practical utility and portability to other contexts. Furthermore, the socio-economic characteristics of residential wood burning in high income countries are poorly understood. Methods: we used open data from 26 million Energy Performance Certificates (EPCs) for properties in England and Wales from January 2009 to February 2025 to map the concentration and prevalence of wood burners within small areas. We evaluated our method against the UK national wood burning emissions inventory using national air pollution monitoring networks. We used novel open data linkages to characterise associations between area-level prevalence of wood burners and socio-economic factors including deprivation, ethnicity, and age. Findings: we identified substantial spatial heterogeneity in the concentration of wood burners, with the highest concentrations in affluent urban areas. Our EPC-based concentration metric was more strongly correlated with peaks in winter PM2.5 at urban monitoring sites than estimates from the UK national emissions inventory. Prevalence of wood burners was positively correlated with age and percentage of residents identifying as ethnically white,and negatively correlated with measures of social deprivation. Prevalence of wood burners in EPCs has increased since 2009. Conclusions: EPCs are a valuable data source which policymakers can use to target local interventions or extend existing restrictionson solid fuel burning. Our method is transparent, up-to-date, and portable to other countries where similar EPC data is available. The relationship between social deprivation and prevalence of wood burning heat sources highlights important issues of environmental justice. Epidemiological analyses of wood smoke exposures and health should carefully account for the confounding effects of age, deprivation, and ethnicity
Brief psychological interventions for schizophrenia: a systematic review and meta-analysis
No full textBackground: although cognitive behavioral therapy for people diagnosed with schizophrenia (CBTp) is recommended in clinical guidelines internationally, rates of implementation are low. One consequence of this has been the development of brief individual psychological interventions, which are shorter than the recommended minimum of 16 sessions for CBTp. This article is the first to systematically identify the brief interventions that exist for people diagnosed with schizophrenia and to determine their effectiveness using meta-analysis.Methods: five electronic databases (PsycINFO, MEDLINE, CINAHL, EMBASE, and Web of Science) were searched for peer-reviewed randomized controlled trials or experimental studies of brief individual psychological interventions delivered in community settings. Random effects meta-analysis was used to integrate effect sizes, due to the heterogeneity of included studies.Results: fourteen studies were identified (n = 1,382) that measured thirty clinical outcomes and included six intervention types - brief CBT, memory training, digital motivation support, reasoning training, psychoeducation, and virtual reality. Collectively, brief psychological interventions were found to be effective for psychotic symptoms (SMD −0.285, p < 0.01), paranoia (SMD −0.277, p < 0.05), data gathering (SMD 0.38, p < 0.01), depression (SMD −0.906, p < 0.05) and wellbeing (SMD 0.405, p < 0.01). For intervention types, brief CBT was effective for psychotic symptoms (SMD −0.32, p < .001), and reasoning training was effective for data gathering (SMD 0.38, p < 0.01).Conclusions: overall, the evidence suggests that brief psychological interventions are effective for several key difficulties associated with schizophrenia, providing an opportunity to improve both access to, and choice of, treatment for individuals diagnosed with schizophrenia
Using gravitational waves to see the first second of the Universe
No full textGravitational waves are a unique probe of the early Universe, as the Universe is transparent to gravitational radiation right back to the end of inflation. This review summarizes detection prospects and the wide scope of primordial events that could lead to a detectable stochastic gravitational wave background. Any such background would shed light on what lies beyond the standard model, sometimes at remarkably high scales. The range of strategies for detecting a stochastic gravitational wave background is overviewed before the review delves into three major primordial events that can source such a background. Finally, the landscape of other sources of primordial backgrounds is summarized
Intolerance of uncertainty, paranoia, and prodromal symptoms: comparisons between a schizophrenia-spectrum disorder, anxiety disorder, and non-clinical sample
No full textBackground: Greater Intolerance of Uncertainty (IU: the tendency to find uncertainty negative) is associated with greater paranoia (mistrust of others) in clinical samples with schizophrenia spectrum disorders (SSDs). Questions remain on whether the relationship between IU and paranoia/prodromal symptoms is: (1) specific over other related negative affective traits and cognitive biases, and (2) specific to SSDs or is transdiagnostic.Methods: to examine these research questions, we conducted a survey in those with SSDs (n = 103), anxiety disorders (n = 102) a non-clinical sample (n = 102). Questionnaires included: IU, paranoia, prodromal symptoms of schizophrenia, neuroticism and jumping to conclusions bias.Results: IU, neuroticism and jumping to conclusions bias were elevated in those with SSDs and anxiety disorders, compared to the non-clinical group. Both paranoia and prodromal symptoms were highest in those with SSDs, then anxiety disorders and lowest in the non-clinical group. Greater IU was associated with greater paranoia and prodromal symptoms across SSDs, anxiety disorders and a non-clinical sample. The majority of the relationships between IU and paranoia/prodromal symptoms remained significant when controlling for neuroticism and the jumping to conclusions bias. However, the relationship between IU and paranoia in the SSD group was not specific over the jumping to conclusions bias.Discussion: these findings highlight the potentially transdiagnostic role of IU in paranoia/prodromal symptoms across SSDs and anxiety disorders, which has implications for the development of transdiagnostic treatment interventions for SSDs and anxiety disorders
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