143174 research outputs found
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Large, fast and accurate HI intensity maps with latent overlap diffusion
No full textThe distribution of 21 cm emission from neutral hydrogen is a powerful cosmological and astrophysical probe, as it traces the underlying dark matter and cold gas distributions throughout cosmic times. However, the prediction of observable signals is hindered by the large computational costs of the required hydrodynamic simulations. We introduce a novel machine learning pipeline that, once trained on a hydrodynamical simulation, is able to generate both halo mass density maps and the three-dimensional 21 cm brightness temperature signal, starting from a dark matter-only simulation. We use an attention-based ResUNet (HALOgen) to predict dark matter halo maps, which are then processed through a trained conditional variational diffusion model (LODI) to produce 21 cm brightness temperature maps. LODI is trained on smaller sub-volumes that are then seamlessly combined in 512-times larger volume using a new method, called ‘latent overlap’. We demonstrate that, once trained on 253 (Mpc/h)3 volume simulations, we are able to predict the 21 cm power spectrum on an unseen dark matter map (with the same cosmology) to within 10% for wavenumbers k ≤ 10 h Mpc−1, deep inside the non-linear regime, with a computational effort of the order of two minutes. While demonstrated on this specific volume, our approach is designed to be scalable to arbitrarily large simulations
A whole population-based cohort study of the trajectory of the prevalence and the incidence of mental illness, challenging behaviour, and psychotropic medication prescribing in adults with intellectual disabilities in the Czech Republic between 2010 and 2022
No full textBackground
It is essential to understand the complex interaction among mental illness, challenging behaviour and psychotropic medication prescribing among adults with intellectual disabilities to help reduce overmedication of psychotropics.
Methods
We analysed data from the Institute of Health Information and Statistics of the Czech Republic to estimate the prevalence of mental illness, challenging behaviour and psychotropic prescribing between 2010 and 2022 and incidence between 2015 and 2022.
Results
62,636 (54% males) adults with intellectual disabilities contributed 704,503 person-years of data. In 2010, the prevalence of concomitant mental illness (ICD-10, F20-48) was 15·7%, challenging behaviour 29% and any psychotropic prescription 55%, increasing in 2022 to 17·3%, 30·5% and 59%, respectively. The prevalence of most individual mental illness categories either remained the same or marginally increased between 2010 and 2022, except anxiety disorders, the neurodevelopmental disorders like autism and attention-deficit hyperactivity disorder (ADHD), which showed a significant increase. The incidence of new diagnoses of mental illnesses and challenging behaviour decreased between 2015 and 2022, except for the neurodevelopmental disorders, which increased significantly. The incidence of challenging behaviour correlated significantly with psychoses, bipolar disorder, and anxiety disorder. The overall prevalence of most psychotropic prescribing correlated significantly with the prevalence of mental illnesses and challenging behaviour. Among those receiving antipsychotics, only 18% in 2010 and 19% in 2022 had severe mental illness (psychoses and/or bipolar disorder), which are the licensed indications for long-term antipsychotic prescriptions. In 2010, among those with challenging behaviour, 82% received psychotropics, 62% antipsychotics, 20% antidepressants, 17% anxiolytics, 30% mood stabilisers, and 0·4% hypnotics and sedatives. The incidence rates of new prescriptions among participants who displayed challenging behaviour fell for any psychotropics, antipsychotics, antidepressants and anxiolytics. However, the incidence of new prescriptions increased for mood stabilisers, and significantly for hypnotics/sedatives (Incidence Rate Ratio: 0.61; 95% Confidence Interval: 0.45–0.81; p < 0.001).
Conclusions
Challenging behaviour was significantly associated with some mental illnesses. Both mental illness and challenging behaviour were significantly associated with psychotropic medication prescribing. The prevalence of psychotropic medication prescribing overall and especially among those displaying challenging behaviour was high and showed a significant increase in antidepressants and hypnotics/sedatives prescriptions over 12 years
Serpentinisation-driven remagnetisation in ophiolites: insights from the troodos ophiolite, Cyprus
No full textSerpentinisation of ultramafic rocks occurs in various tectonic settings, from seafloor hydration to subduction dehydration and ophiolite emplacement. It is known to promote magnetite formation, leading to remagnetisation events; however, serpentinisation-driven remagnetisation is often temporally and spatially complex due to the overprinting and mixing of multiple episodes of serpentinisation. This is particularly true in ophiolites that undergo prolonged alteration from ridge-axis formation to subduction-zone emplacement. To quantify serpentinisation-driven remagnetisation in ophiolites, I undertook a magnetic study in the Troodos ophiolite, Cyprus where the serpentinisation history was poorly constrained. A multi-scale magnetic approach was applied to resolve this, including mineral-scale magnetic imaging, bulk-sample-scale rock magnetic measurements, palaeomagnetic directional analysis and kilometre-scale magnetic modelling based on aeromagnetic data. My results highlight three stages of serpentinisation-driven remagnetisation events, from ridge-axis serpentinisation during seafloor spreading, through mantle-wedge serpentinisation in the subduction zone, to meteoric-associated serpentinisation after surface exposure of ultramafic rocks. Ridge-axis serpentinisation occurs in the high-temperature (> 200 °C), leading to highly magnetic serpentinite; mantle wedge and meteoric water-related serpentinisation processes are low-temperature (< 180-200 °C), giving rise to weakly magnetic serpentinite. These new insights support a serpentinite diapir emplacement of the Troodos mantle sections in the subduction zone, despite ridge-axis serpentinisation occurring in the lower-crust cumulate zone. This study also addresses how the rock magnetic properties of serpentinite respond to increasing deformation within an oceanic transform fault zone as preserved in the Troodos ophiolite. During deformation, the dominant serpentine mineral changes from lizardite to chrysotile and magnetite forms from iron released during this recrystallisation. Increasing deformation facilitates seawater circulation, which increases the water–rock ratio and promotes the growth of coarse magnetite grains. This work highlights the remagnetisation process that occurs during the progressive shearing of a transform fault, with a 90° rotation of palaeomagnetic directions preserved in variably deformed serpentinites.Open Acces
Cannabis use and analgesic prescribing in UK primary care: a retrospective cohort study of patients with osteoarthritis
No full textObjectives: This study aims to assess differences in analgesia prescribing in UK primary care between individuals with osteoarthritis who have a recorded exposure to cannabis use and those who do not. Methods: This population-based retrospective cohort study included opioid-naïve patients with osteoarthritis (aged 25–85 years) who were active in Clinical Practice Research Datalink Aurum between 1 January 1995 and 15 December 2023. Patients with osteoarthritis who had current or historic cannabis use recorded were matched to two unexposed individuals by age, sex, smoking status, and health authority. Patients were followed up to assess prescriptions of analgesia. Cox regression was performed adjusted for age, sex, and ethnicity. Results: 662 exposed patients were matched to 1319 unexposed patients. Cannabis-exposed individuals were more likely to be prescribed opioids (adjusted hazard ratio (HR): 2.06; 95% confidence interval (CI): 1.74–2.43; p < 0.001), gabapentinoids (HR: 3.31; 95% CI: 2.34–4.67; p < 0.001), non-steroidal anti-inflammatory drugs (HR: 1.99; 95% CI: 1.72–2.31; p < 0.001), tricyclic antidepressants (HR: 2.64; 95% CI: 2.03–3.44; p < 0.001), other antidepressants (HR: 7.22; 95% CI: 5.24–9.94; p < 0.001), and paracetamol (HR: 3.30; 95% CI: 2.43–4.48; p < 0.001). Conclusions: This study suggests there is an association between coded exposure to cannabis in UK primary care records and increased prescribing of analgesia. Given the relative scarcity of recorded cannabis use relative to its prevalence in the general population, these findings must be interpreted cautiously. The increased hazard of using analgesia and mortality within the cannabis-exposed cohort may be confounded by socioeconomic status and a higher likelihood of coding cannabis use in those experiencing adverse effects after consumption or cannabis misuse disorder
Prescription refill adherence before and after patient portal registration in among General Practice patients in England using the Clinical Practice Research Datalink: longitudinal observational study
No full textBackground: Patient portal use has been associated with improved patient health and improved adherence to medications, including statins. However, there is limited research on the association between patient portal registration and outcomes such as statin prescription refill adherence in the context of the National Health Service of England, where patient portals have been widely available since 2015.
Objective: We aimed to explore statin prescription refill adherence among general practice patients in England.
Methods: This study was approved by the Clinical Practice Research Datalink Independent Scientific Advisory Committee (ID: 21_000411). We used patient-level general practice data from the Clinical Practice Research Datalink in England. The data included patients with cardiovascular disease, diabetes, and chronic kidney disease, who were registered on the patient portal. The primary aim was to investigate whether statin prescription refill adherence, defined as ≥80% adherence based on the medication possession ratio, improved after patient portal registration. We used a multilevel logistic regression model to compare aggregate adherence 12 months before and 12 months after patient portal registration.
Results: We included 44,141 patients in the study. The analysis revealed a 16% reduction in the odds of prescription refill adherence 12 months after patient portal registration (odds ratio [OR]: 0.84, 95% CI 0.81-0.86) compared to 12 months before registration in the fully adjusted model for patient- and practice-level variables.
Conclusions:
This study evaluated prescription refill adherence after patient portal registration. Registering to the portal does not fully explain the mechanisms underlying the relationship between patient portal use and health-related outcomes such as medication adherence. Although a small reduction in prescription refill adherence was observed, this reduction disappeared when the follow up time was reduced to 6 months. Given the limitations of the study, reduction in prescription refill adherence cannot be entirely attributable to patient portal registration. However, there may be potential confounding factors influencing this association which should be explored through future research
Flash thermal racemization of chiral amine in continuous flow: an exploration of reaction space using doe and multivariate transient flow
No full textThe robustness of the flash thermal racemization of optically active 1-phenylethylamine over Pd/γ-Al2O3 was studied by applying split-plot design-of-experiments (DoE), where the effects of temperature, flow rate, and concentration (3-factors) on the e.e. and selectivity (2-responses) were examined and quantified. The same effects were also interrogated using multivariate ramps in transient flow to produce response surfaces for the reaction space. The same set of optimal conditions for the process was identified by both approaches, and the same relationships between the variables were observed: while the extent of racemization (e.e.) can be directly correlated to temperature, a more complex relationship between temperature and flow rate on the selectivity was uncovered
The utility of spirometry and single breath gas transfer measurements to identify low total lung capacity
No full textBackground
Measurement of total lung capacity (TLC) requires large and expensive equipment. We aimed to investigate whether spirometric restriction and low alveolar volume measured by single breath gas transfer (VA) can be used to identify those with a low TLC.
Methods
We retrospectively analysed data from adults referred to Cambridge University Hospitals between January 2016 and December 2023. We investigated the utility of spirometric restriction (FVC <LLN with FEV1/FVC ≥LLN) and reduced VA (<LLN), to discriminate low TLC measured by plethysmography (TLCpleth <LLN). We assessed agreement between definitions using the Cohen's Kappa coefficient and the discriminative ability of spirometric restriction and reduced VA to identify TLCpleth <LLN.
Results
Data from 7923 patients were included. The majority (94%) of patients were of European ancestry, 51% were female. Mean age was 58 years. 11% of patients had a TLCpleth <LLN, of which 27% also had spirometric restriction, and 95% had a VA <LLN. Agreement between spirometric restriction and TLCpleth <LLN was fair (kappa =0.37). Spirometric restriction had low sensitivity (27%) but high specificity (99%) for discriminating TLCpleth <LLN. Agreement between VA <LLN and TLCpleth <LLN was substantial (kappa=0.63). VA <LLN had good sensitivity (95%) and specificity (89%) for discriminating TLCpleth <LLN, except for in patients with the most severe airflow obstruction.
Conclusions
A FVC in the healthy range is an effective tool for ruling out restriction. Low VA can be used to accurately identify those with a low TLC, negating the need for formal measurement of static lung volumes when identifying restrictive lung disease
Cost-effectiveness of total shoulder arthroplasty compared to hemiarthroplasty. A study using data from the National Joint Registry
No full textObjectives The aim of this study was to compare the cost-effectiveness of total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) and explore variation by age and gender.
Design Cost-effectiveness analysis using a lifetime cohort Markov model.
Setting National population registry data.
Participants Model parameters were informed by propensity score-matched comparisons of TSA and HA in patients with osteoarthritis and an intact rotator cuff using data from the National Joint Registry.
Interventions TSA and HA.
Primary outcome measures Quality-adjusted life years (QALYs) and healthcare costs for age and gender subgroups. A probabilistic sensitivity analysis was performed.
Results In all subgroups, TSA was more cost-effective, with the probability of being cost-effective about 70% for TSA versus 30% for HA at any willingness-to-pay threshold above £1100 per QALY. TSA was dominant in young patients (≤60 years) with a mean cost saving of £463 in men and £658 in women, and a mean QALY gain of 2 in both men and women. In patients aged 61–75 years, there was a mean cost saving following HA of £395 in men and £181 in women, while QALYs remained superior following TSA with a 1.3 gain in men and 1.4 in women. In the older cohort (> 75 years), the cost difference was highest and the QALY difference was lowest; there was a cost-saving following HA of £905 in men and £966 in women. The mean QALY gain remained larger after TSA: 0.7 in men and 0.9 in women.
Conclusion TSA was more cost-effective than HA in patients with osteoarthritis. QALYs were superior following TSA in all patient groups. Cost differences varied by age and TSA was dominant in young patients
Identification of barriers and needs in the discontinuation of benzodiazepine receptor agonists in elderly patients of a rural community—a qualitative study
No full textBackground/Objectives: The predictors of successful discontinuation of benzodiazepine agonist receptors (BZRA) in elderly patients are not well known due to lack of research on the subject, and there is a need for further investigation, with more focus from the patients’ point of view. No previous studies were identified that have been conducted in Portugal on this subject. We proposed to identify the barriers and facilitators in the discontinuation of BZRA from the perceptions of elderly patients under prolonged prescription of BZRA, belonging to the same rural community. The contributions for further research are intended to be the identification of potential intervention targets directed at patients to reduce the prevalence of elderly patients under prolonged prescription of BZRA. Methods: A set of 15 semi-structured interviews with patients under prolonged prescription of BZRA was conducted. Content analysis was done by the main researcher and a reviewer to identify original emerging themes for the two underlying domains. Results: Four themes were identified as barriers to the discontinuation of BZRA: (1) patient characteristics, (2) clinical factors, (3) medication-related factors, and (4) context and external factors. Seven themes were identified as facilitators to the discontinuation of BZRA: (1) motivation, (2) patients’ knowledge, (3) perception of BZRA insufficiency, (4) access to written information, (5) access to alternatives, (6) time for decision-making, and (7) attitudes of health professionals. Conclusions: The findings highlight the challenging nature of BZRA discontinuation and the range of barriers and facilitators that impact patients’ behaviour towards this purpose. We subdivided the elements identified in two areas, therefore aiming at producing significant knowledge to outline potential intervention targets
Heterogeneous graph neural networks with post-hoc explanations for multi-modal and explainable land use inference
No full textRecently, the increased use of sensor and location technologies has facilitated the collection of multi-modal mobility data, offering valuable insights into daily activity patterns. Many studies have adopted advanced data-driven techniques to explore the potential of these multi-modal mobility data in land use inference. However, existing studies often process samples independently, ignoring the spatial correlations among neighbouring objects and heterogeneity among different services. Furthermore, the inherently low interpretability of complex deep learning methods poses a significant barrier in urban planning, where transparency and extrapolability are crucial for making long-term policy decisions. To overcome these challenges, we introduce an explainable framework for inferring land use that synergises heterogeneous graph neural networks (HGNs) with Explainable AI techniques, enhancing both accuracy and explainability. We evaluate the proposed approach on three cities with different urban layout and mobility combinations: London (with tube, bus and bike sharing data sources), San Francisco (parking and bike sharing), and New York City (metro and bike sharing). The empirical experiments demonstrate that the proposed HGNs significantly outperform baseline graph neural networks for all six land use indicators, especially in terms of ‘office’ and ‘sustenance’. We then deploy feature attribution (at both temporal and spacial levels) and counterfactual explanations, which shed light on several important findings. The node-based feature attribution explanations show that the symmetrical nature of the ‘residence’ and ‘work’ categories predicted by the framework aligns well with the commuters’ ‘work’ and ‘recreation’ activities. Meanwhile, the spatial feature attribution explanations indicates that the heightened central importance of commercial categories and the dominance of residential influences in outer zones align closely with typical urban structures. Finally, the counterfactual explanations reveal that variations in node features and types are primarily responsible for the differences observed between the predicted land use distribution and the ideal mixed state. These analyses demonstrate that the proposed HGNs can suitably support urban stakeholders in their urban planning and policy-making. The source code is available at https://github.com/xuehao0806/GNN-land-use