922017 research outputs found
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Model order reduction of layered waveguides via rational Krylov fitting
No full textRational approximation recently emerged as an efficient numerical tool for the solution of exterior wave propagation problems. Currently, this technique is limited to wave media which are invariant along the main propagation direction. We propose a new model order reduction-based approach for compressing unbounded waveguides with layered inclusions. It is based on the solution of a nonlinear rational least squares problem using the RKFIT method. We show that approximants can be converted into an accurate finite difference representation within a rational Krylov framework. Numerical experiments indicate that RKFIT computes more accurate grids than previous analytic approaches and even works in the presence of pronounced scattering resonances. Spectral adaptation effects allow for finite difference grids with dimensions near or even below the Nyquist limit
‘Ways of being’ in the domestic garden for people living with dementia: doing, sensing and playing
No full textDomestic gardens represent a site for enacting embodied identity and social relationships in later life, and negotiating tensions between continuity and change. In the context of dementia, domestic gardens have significant implications for ‘living well’ at home, and for wider discussions around embodiment, relational selfhood and agency. Yet previous studies exploring dementia and gardens have predominantly focused on care home or community contexts. In light of this, the paper explores the role of domestic gardens in the everyday lives of people living with dementia and their households, using qualitative, creative methods. This includes filmed walking interviews and garden tours, diaries and sketch methods, involving repeat visits with six households in England. Findings are organised thematically in relation to different ‘ways of being’ in the garden: working in and doing the garden; being in and sensing; and playing, empowerment and agency. These different ‘ways of being’ are situated within relationships with household members, neighbours, and non-human actors including pets, wildlife and the materiality of the garden. Garden practices illustrate continuity, situated within embodied biographies and habitus. However, identities, practices and gardens are also subject to ongoing readjustment and reconstruction. The conclusion discusses implications for extending literature on gardens and later life, describing how social and material relationships in domestic gardens are renegotiated in the context of dementia, while highlighting opportunities for ‘play’, active sensing and agency. We also explore contributions to understandings of dementia, home and place, and implications for garden design and care practice
Potentials and Limits of Using Preconfigured Spatial Beams as Bandwidth Resources: Beam Selection vs Beam Aggregation
No full textThis letter studies how to use spatial beams preconfigured in a legacy spatial division multiple access (SDMA) network as bandwidth resources via the implementation of nonorthogonal multiple access (NOMA). Two different beam management schemes, namely beam selection and beam aggregation, are developed to improve the overall system throughput without consuming extra spectrum or changing the performance of the legacy network. Analytical and simulation results are presented to show that the two schemes realize different tradeoffs between system performance and complexity
Angiotensin receptor blockade is associated with increased risk of giant cell arteritis
No full textBackground. Angiotensin II is implicated in giant cell arteritis (GCA) pathology. We examined whether the use of angiotensin receptor blockers (ARB) is associated with GCA risk, compared with ACE inhibitors (ACEi) or other antihypertensives.Methods. We performed a matched cohort study including adults who were initiators of antihypertensives in UK primary care data between 1995 and 2019. Treatment naïve individuals without prior GCA or polymyalgia rheumatica (PMR) were categorised into three groups – ARB initiators, ACEi initiators, or other antihypertensive initiators (beta-blockers, calcium channel blockers, diuretics or alpha-adrenoceptor blockers) – and followed for up to 5 years. Incident GCA was defined using validated Read codes, with age of onset ≥50 years and ≥2 glucocorticoid prescriptions. Inverse-probability-weighted Cox models were used to model outcome risk, adjusting for lifestyle parameters, comorbidities, and comedications.Results. Among over a million new starters of antihypertensives (81,780 ARB, 422,940 ACEi, and 873,066 other antihypertensives), the incidence rate of GCA per 10,000 patient-years was 2.73 (95%CI 2.12-3.50) in the ARB group, 1.76 (95%CI 1.25-2.39) in the ACEi group, and 1.90 (95%CI 1.37-2.56) in other antihypertensive group. The hazard of GCA was higher in ARB initiators (HR 1.55; 95%CI 1.16-2.06) than initiators of ACEi, but similar between initiators of other antihypertensives and ACEi (HR 1.08; 95%CI 0.87-1.35).Conclusions. Initiation of ARB is associated with higher risk of GCA compared to ACEi or other antihypertensives. Mechanistic studies of angiotensin receptor biology will provide further clarity for our findings
Two-stage Classification for Detecting Murmurs from Phonocardiograms Using Deep and Expert Features
No full textDetection of heart murmurs from stethoscope sounds is a key clinical technique used to identify cardiac abnormalities. We describe the creation of an ensemble classifier using both deep and hand-crafted features to screen for heart murmurs and clinical abnormality from phonocardiogram recordings over multiple auscultation locations. The model was created by the team Murmur Mia! for the George B. Moody PhysioNet Challenge 2022.Methods: Recordings were first filtered through a gradient boosting algorithm to detect Unknown. We assume that these are related to poor quality recordings, and hence we use input features commonly used to assess audio quality. Two further models, a gradient boosting model and ensemble of convolutional neural networks, were trained using time-frequency features and the mel-frequency cepstral coefficients (MFCC) as inputs, respectively. The models were combined using logistic regression, with bespoke rules toconvert individual recording outputs to patient predictions.Results: On the hidden challenge test set, our classifier scored 0.755 for the weighted accuracy and 14228 for clinical outcome challenge metric. This placed 9/40 and 28/39 on the challenge leaderboard, for each scoring metric, respectively.<br/
A genome-wide association study with tissue transcriptomics identifies genetic drivers for classic bladder exstrophy
No full textClassic bladder exstrophy represents the most severe end of all human congenital anomalies of the kidney and urinary tract and is associated with bladder cancer susceptibility. Previous genetic studies identified one locus to be involved in classic bladder exstrophy, but were limited to a restrict number of cohort. Here we show the largest classic bladder exstrophy genome-wide association analysis to date where we identify eight genome-wide significant loci, seven of which are novel. In these regions reside ten coding and four non-coding genes. Among the coding genes is EFNA1, strongly expressed in mouse embryonic genital tubercle, urethra, and primitive bladder. Re-sequence of EFNA1 in the investigated classic bladder exstrophy cohort of our study displays an enrichment of rare protein altering variants. We show that all coding genes are expressed and/or significantly regulated in both mouse and human embryonic developmental bladder stages. Furthermore, nine of the coding genes residing in the regions of genome-wide significance are differentially expressed in bladder cancers. Our data suggest genetic drivers for classic bladder exstrophy, as well as a possible role for these drivers to relevant bladder cancer susceptibility
Approach to the Patient with Short Stature: Genetic Testing
No full textThe first step in the evaluation of the short child is to decide whether growth parameters in the context of the history are abnormal or a variant of normal. If growth is considered abnormal, system and hormonal tests are likely to be required, followed by more directed testing, such as skeletal survey and/or genetic screening with karyotype or microarray. In a small percentage of short children in whom a diagnosis has not been reached, this will need to be followed by detailed genetic analysis; currently exome sequencing using targeted panels relevant to the phenotype is the commonly used test. Clinical scenarios are presented that illustrate how such genetic testing can be used to establish a molecular diagnosis, and how that diagnosis contributes to the management of the short child. New genetic causes for short stature are being recognised on a frequent basis, while the clinical spectrum for known genes is being extended. We recommend that an international repository for short stature conditions is established for new findings to aid dissemination of knowledge, but also to help in the definition of the clinical spectrum both for new and established conditions