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Mid-crustal strain localisation triggered by localised fluid influx and activation of dissolution–precipitation creep
Get PDFUnderstanding mid-crustal deformation is vital for determining the spatial and temporal distribution of strain localisation, with implications for upper-crust deformation including seismic hazard. Here, we conduct fieldwork and microstructural and minerochemical analyses on the amphibolite-facies, 100-m-wide Upper Badcall shear zone in northwest Scotland, which deforms initially anhydrous quartzofeldspathic gneiss and a mafic dyke. We show that with increasing strain, m-scale strain distribution and mineral chemistry become increasingly homogeneous, while hydrous phases and syntectonic quartz veins become more abundant. With increasing strain there is an overall increase in grain size, grain boundary alignment and shape preferred orientation in amphibole, plagioclase and quartz. Only amphibole and large grained quartz exhibit crystallographic preferred orientation in strained areas. Subtle microstructures that may be overlooked elsewhere, particularly in felsic gneiss, indicate dominant activity of dissolution–precipitation creep and equivalent rheological weakening in both mafic and felsic rocks. We propose that brittle fractures, now preserved as syntectonic quartz veins, allowed localised fluid-infiltration in previously anhydrous crust. This triggered local retrogressive reactions and introduced sufficient grain boundary fluid for deformation to favour dissolution–precipitation creep over dislocation creep. Our study suggests that dissolution–precipitation creep may be more dominant in mid- to lower-crustal localised zones of deformation than previously thought
High Q-contrast terahertz quantum cascade laser via bandgap-confined bound state in the continuum
No full textPhotonic bound states in the continuum (BICs) are optical modes that remain highly localized despite co-existing with radiating waves in the continuum, attracting considerable attention for both fundamental studies and technological innovations. Conventional single-mode BIC lasers predominantly focus on maximizing the Q-factor of a specific mode, often overlooking the critical role of Q-contrast – the difference in Q-factors between the highest-Q BIC mode and competing modes – which is crucial for achieving stable single-mode lasing. In this study, we present a compact, high Q-contrast BIC laser, enabled by strategically optimizing the alignment of the TM1 band of the core domain with the shell domain to confine the high Q-factor mode within the core. Using a quantum cascade laser chip operating in the terahertz (THz) regime, this design achieves a Q-contrast ratio of approximately 2.3, resulting in stable single mode lasing across the dynamic region with a side-mode suppression ratio of ∼20 dB. These findings underscore the pivotal role of Q-contrast in photonic lasers, with promising implications for applications in THz lasers, sensors, harmonic signal generators and modulators
Pore-scale prediction of transport properties in lithium-ion battery cathodes during calendering using DEM and CFD simulations
Get PDFCalendering is a crucial step in the production of lithium-ion batteries (LIBs), due to its significant effect on key parameters of porous electrode structure and resultant performance. This study investigates the influence of calendering degree (compression) on porosity, tortuosity and permeability for different particle configurations. With this motivation, the mechanical behaviour of electrode structures was conducted with Discrete Element Method (DEM), and the electrolyte flow as a continuous phase was described using pore-scale computational fluid dynamics (CFD) simulations. Three different electrode microstructures were generated comprising mono-disperse and polydisperse spherical particles, as well as mono-disperse ellipsoidal particles. The predicted pore-scale properties are used in validated electrochemical–thermal models to correlate calendering process to the overall LIB performance. The results revealed that using the ellipsoidal particles, an anisotropy in tortuosity and permeability appeared with the beginning of the compression process. As the compression degree increased to 30%, the level of anisotropy decreased, and as a consequence, the discrepancy of diagonal components of tortuosity and permeability decreased. The electrochemical–thermal models show that it is best to keep the calendering rate around 20% with smaller particle sizes (for both spherical and ellipsoidal cases)
Beyond national identity: The positive role of local identity in shaping attitudes to international and internal migration
No full textResearch on the link between social identification and attitudes toward immigration has primarily focused on national identification and international migrants, often overlooking the local level. Combining social identity theory and a place identity perspective on intergroup dynamics, we examine national and local identification, as well as their interplay, as determinants of attitudes toward international and internal migration. Our analysis is based on nationally representative samples from Austria, Czechia, Germany, Hungary, Poland, and Slovakia (N = 10,765) from the Central European Social Survey (2021–2022). We found that national identity was associated with more negative attitudes toward international migration, but not internal migration. In contrast, local identity was linked to more welcoming attitudes toward both international and internal migration, and it neutralized the negative effect of national identity on attitudes toward international migration. Overall, our findings highlight the inclusive role of local identity in shaping immigration attitudes, particularly in contexts characterized by high anti-immigrant sentiment
Decentralised construction of a global coordinate system in a large swarm of minimalistic robots
Get PDFCollective intelligence and autonomy of robot swarms can be improved by enabling individual robots to become aware that they are the constituent parts of a larger whole and to identify their role within the swarm. In this study, we present an algorithm to enable positional self-awareness in a swarm of minimalistic, error-prone, stationary robots which can only locally broadcast messages and estimate the distance from their neighbours. Despite being unable to measure the bearing of incoming messages, the robots running our algorithm can calculate their position within a swarm deployed in a regular formation. We show through experiments with up to 200 Kilobot robots that such positional self-awareness can be employed by the robots to create a shared coordinate system and dynamically self-assign location-dependent tasks. Our solution has fewer requirements than state-of-the-art algorithms and includes collective noise-filtering mechanisms. Therefore, it has an extended range of robotic platforms on which it can run. All robots are interchangeable, run the same code, and do not need any prior knowledge. Through our algorithm, robots reach collective synchronisation and autonomously become aware of the swarm’s spatial configuration and their position within it
Diagnostic performance of morning serum cortisol for glucocorticoid weaning in children and adults
Get PDFDesign
Morning cortisol predicts the outcome of the short synacthen test (SST). There is a paucity of studies examining this in a dedicated cohort of children and adults weaning off glucocorticoids and using a modern immunoassay. This study aimed to identify early morning serum cortisol (EMC) cut-offs which predict the SST outcome in children and adults during glucocorticoid weaning.
Methods
A retrospective cohort study of pediatric and adult patients on long-term glucocorticoids with suspected glucocorticoid-induced adrenal insufficiency (GIAI) undergoing an SST. Our main outcomes were cut offs with 95% and 99% sensitivity and specificity for EMC analysed on modern immunoassays, determined via receiver operating characteristic (ROC) curve analysis. A pass on SST was defined as 30-min cortisol of ≥430 nmol/L (15.6 µg/dL).
Results
151 and 372 SSTs were included in the pediatric and adult cohorts, respectively, of which 32% and 37% were passed. ROC curve analysis demonstrated that EMC performed well in both cohorts with area under curve (AUC) of 0.79 (95% CI, 0.71, 0.87) and 0.88 (95% CI, 0.84, 0.91), respectively. EMC cut offs to predict a pass on SST were 278 (10.1 µg/dL) and 290 nmol/L (10.5 µg/dL) at 95% sensitivity, and 316 (11.5 µg/dL) and 349 nmol/L (12.7 µg/dL) at 99% sensitivity, respectively. Further analysis in adults showed that using a 95% cut off in clinical practice was effective as 48/51 patients with EMC between 290 and 349 nmol/L (10.5-12.7 µg/dL), were weaned off without adverse events.
Conclusion
Morning serum cortisol can predict the SST outcome in children and adults weaning from glucocorticoids. An EMC > 290 nmol/L in adults predicts a patient can stop glucocorticoid therapy and will recover adrenal function
Representing pollution at the agrarian-urban frontier: participatory documentary film‐making in Bar Elias, Lebanon
Get PDFThe Beqaa Valley in Lebanon has become increasingly polluted, and residents are attributing illness to improper waste disposal and dumping. This article explores local epistemologies of pollution’s causes and effects in three films, which were researched and produced by local residents of Bar Elias, a small town in the Beqaa, which has rapidly urbanized as a consequence of mass forced migration to the area. We approach pollution in Bar Elias as a form of slow violence whose causes and effects become more available to understanding through local epistemologies. The films speak through visuals of dirt, waste and discolouration, as well as inter‐generational and cross‐community storytelling. We suggest that the filmmakers are thus able to reign in the complex and dissipating connections between polluters and pollutants that challenge slow violence by adopting a spatial lens on broad struggles impacting Syrian, Lebanese and Palestinian residents. This spatial lens foregrounds pollution as an outcome of Bar Elias’ location at the agrarian‐urban frontier—a distinct political geography from which we analyze power relations that create pollution and expose communities to harm. We argue that this political geography lens on the films offers a promising epistemology of slow violence
Global optimal estimation retrievals of atmospheric carbonyl sulfide over water from IASI measurement spectra for 2018
Get PDFCarbonyl sulfide (OCS) is consumed by vegetation during photosynthesis in a one-way hydrolysis reaction, making measuring OCS vegetative uptake a means of inferring and quantifying global gross primary production. Recent studies highlight that uncertainties in OCS surface fluxes remain high and OCS datasets with better spatial coverage are required, particularly from satellite. Here OCS profiles are retrieved using measured radiances from the Infrared Atmospheric Sounding Interferometer (IASI) instruments. We estimate total column amounts over oceanic and inland water regions for the example year 2018, using an optimal estimation scheme, using the University of Leicester IASI retrieval scheme (ULIRS) for selected microwindows in the 2000–2100 cm−1 wavenumber range. Information content exceeds one between ±50° latitude and a peak in vertical sensitivity around 6–10 km (500–300 hPa) in the troposphere. Diurnal variations are limited to ±2 %, showing larger total column amounts at the daytime overpass. The IASI OCS observations show a correlation of at least 0.74 at half the ground-based flask measurement sites compared. Results also agree with the University of Leeds TOMCAT 3-D chemical transport model simulations within ±5 % throughout most tropical regions. This study demonstrates the ability of the IASI instrument to detect OCS in the troposphere and observe a reasonable seasonal cycle indicative of being driven by photosynthesis. Further data acquisition is recommended to gain insight into inter-annual variability in OCS. This novel work will also help improve our understanding of the role of vegetation in the carbon cycle, particularly when utilised in inversion methods
Automatic detection and sub-typing of primary progressive aphasia from speech: integrating task-specific features and spatio-semantic graphs
Get PDFPrimary progressive aphasia (PPA) describes a group of neurodegenerative diseases that predominantly affect language abilities. Its diagnostic process typically requires experienced clinicians, often available only in specialised hospital departments. Patients with PPA frequently display changes in speech and language early in the disease progression. In this study, we extracted acoustic, linguistic, and task-specific features from audio recordings and evaluated their utility for PPA classification. Using a subset of task-specific features, we detected PPA with 97% accuracy. For sub-typing, models trained on the full feature set achieved 74% accuracy in a three-way classification of PPA variants. Our results highlight the added value of task-specific features, which complement traditional approaches. Additionally, their visualisation offers an intuitive representation of task execution, improving clinical interpretability and potential diagnostic utility
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