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Peter Hujar : speed of life
Peter Hujar was a leading figure of the downtown New York scene of the 1970s and '80s. He is most well-known for his portraits of New York City's artists, musicians, writers, and performers, which feature characters such as Susan Sontag, William S. Burroughs, David Wojnarowicz, and Andy Warhol, and was admired for his completely uncompromising attitude toward work and life. Hujar was a consummate technician, and his portraits of people, animals, and landscapes, with their exquisite black-and-white tonalities, were extremely influential. Underappreciated during his lifetime, Hujar is now a revered icon of the lost downtown art scene, and his photographs are held in permanent collections around the world. Over 160 photographs are gathered in Peter Hujar: Speed of Life. Published alongside a major touring exhibition, this collection presents Hujar's famous portraiture as well as his lesser-known projects.
Book
Analysis of plasmon modes in Bi2Se3/graphene heterostructures via electron energy loss spectroscopy
Topological Insulators (TIs) are promising platforms for Quantum Technology due to their topologically protected surface states (TSS). Plasmonic excitations in TIs are especially interesting both as a method of characterisation for TI heterostructures, and as potential routes to couple optical and spin signals in low-loss devices. Since the electrical properties of the TI surface are critical, tuning TI surfaces is a vital step in developing TI structures that can be applied in real world plasmonic devices. Here, we present a study of Bi
2
Se
3
/graphene heterostructures, prepared using a low-cost transfer method that reliably produces mono-layer graphene coatings on Bi
2
Se
3
flakes. Using both Raman spectroscopy and electron energy loss spectroscopy (EELS), we show that the graphene layer redshifts the energy of the
plasmon mode in Bi
2
Se
3
, creating a distinct surface plasmon that differs significantly from the behaviour of a TI-trivial insulator boundary. We demonstrate that this is likely due to band-bending and electron transfer between the TI surface and the graphene layer. Based on these results, we outline how graphene overlayers can be used to create tuneable, stable plasmonic materials based on topological insulators.
Journal Article
Investigation of hybrid plasmons in a highly crystalline Bi2Se3/C60 heterostructure using low-loss electron energy loss spectroscopy
Topological Insulators (TIs) present an interesting materials platform for nanoscale, high frequency devices because they support high mobility, low scattering electronic transport within confined surface states. However, a robust methodology to control the properties of surface plasmons in TIs has yet to be developed. Surface doping of TIs with molecules may provide tunable control of the two-dimensional plasmons in Bi
2
Se
3
, but exploration of such heterostructures is still at an early stage and usually confined to monolayers. We have grown heterostructures of Bi
2
Se
3
/C
60
with exceptional crystallinity. Electron energy loss spectroscopy (EELS) reveals significant hybridisation of
π
states at the interface, despite the expectation for only weak van der Waals interactions, including quenching of 2D plasmons. Momentum-resolved EELS measurements are used to probe the plasmon dispersion, with Density Functional Theory predictions providing an interpretation of results based on interfacial charge dipoles. This work provides growth methodology and characterization of highly crystalline TI/molecular interfaces that can be engineered for plasmonic applications in energy, communications and sensing.
Topological insulators offer promising potential for nanoscale, high-frequency devices, yet controlling surface plasmon properties remains challenging. Here, the authors grow Bi
2
Se
3
/C
60
heterostructures with exceptional crystallinity, using electron energy loss spectroscopy and density functional theory to reveal significant
π
state hybridization and quenching of 2D plasmons.
Journal Article
Comparison of the International Crowding Measure in Emergency Departments (ICMED) and the National Emergency Department Overcrowding Score (NEDOCS) to measure emergency department crowding: pilot study
IntroductionThere is uncertainty about the best way to measure emergency department crowding. We have previously developed a consensus-based measure of crowding, the International Crowding Measure in Emergency Departments (ICMED). We aimed to obtain pilot data to evaluate the ability of a shortened form of the ICMED, the sICMED, to predict senior emergency department clinicians’ concerns about crowding and danger compared with a very well-studied measure of emergency department crowding, the National Emergency Department Overcrowding Score (NEDOCS).MethodsWe collected real-time observations of the sICMED and NEDOCS and compared these with clinicians’ perceptions of crowding and danger on a visual analogue scale. Data were collected in four emergency departments in the East of England. Associations were explored using simple regression, random intercept models and models accounting for correlation between adjacent time points.ResultsWe conducted 82 h of observation in 10 observation sets. Naive modelling suggested strong associations between sICMED and NEDOCS and clinician perceptions of crowding and danger. Further modelling showed that, due to clustering, the association between sICMED and danger persisted, but the association between these two measures and perception of crowding was no longer statistically significant.ConclusionsBoth sICMED and NEDOCS can be collected easily in a variety of English hospitals. Further studies are required but initial results suggest both scores may have potential use for assessing crowding variation at long timescales, but are less sensitive to hour-by-hour variation. Correlation in time is an important methodological consideration which, if ignored, may lead to erroneous conclusions. Future studies should account for such correlation in both design and analysis.
Journal Article
Investigation of hybrid plasmons in a highly crystalline Bi 2 Se 3 /C 60 heterostructure using low-loss electron energy loss spectroscopy
Topological Insulators (TIs) present an interesting materials platform for nanoscale, high frequency devices because they support high mobility, low scattering electronic transport within confined surface states. However, a robust methodology to control the properties of surface plasmons in TIs has yet to be developed. Surface doping of TIs with molecules may provide tunable control of the two-dimensional plasmons in Bi
Se
, but exploration of such heterostructures is still at an early stage and usually confined to monolayers. We have grown heterostructures of Bi
Se
/C
with exceptional crystallinity. Electron energy loss spectroscopy (EELS) reveals significant hybridisation of
states at the interface, despite the expectation for only weak van der Waals interactions, including quenching of 2D plasmons. Momentum-resolved EELS measurements are used to probe the plasmon dispersion, with Density Functional Theory predictions providing an interpretation of results based on interfacial charge dipoles. This work provides growth methodology and characterization of highly crystalline TI/molecular interfaces that can be engineered for plasmonic applications in energy, communications and sensing.
Journal Article
Analysis of plasmon modes in Bi 2 Se 3 /graphene heterostructures via electron energy loss spectroscopy
Topological Insulators (TIs) are promising platforms for Quantum Technology due to their topologically protected surface states (TSS). Plasmonic excitations in TIs are especially interesting both as a method of characterisation for TI heterostructures, and as potential routes to couple optical and spin signals in low-loss devices. Since the electrical properties of the TI surface are critical, tuning TI surfaces is a vital step in developing TI structures that can be applied in real world plasmonic devices. Here, we present a study of Bi
Se
/graphene heterostructures, prepared using a low-cost transfer method that reliably produces mono-layer graphene coatings on Bi
Se
flakes. Using both Raman spectroscopy and electron energy loss spectroscopy (EELS), we show that the graphene layer redshifts the energy of the π plasmon mode in Bi
Se
, creating a distinct surface plasmon that differs significantly from the behaviour of a TI-trivial insulator boundary. We demonstrate that this is likely due to band-bending and electron transfer between the TI surface and the graphene layer. Based on these results, we outline how graphene overlayers can be used to create tuneable, stable plasmonic materials based on topological insulators.
Journal Article
Service provision for Frailty in European Emergency Departments (FEED): a survey of operational characteristics
Background
The observational Frailty in European Emergency Departments (FEED) study found 40% of older people attending for care to be living with frailty. Older people with frailty have poorer outcomes from emergency care. Current best practice calls for early identification of frailty and holistic multidisciplinary assessment. This survey of FEED sites explores variations in frailty-attuned service definitions and provision.
Methods
This cross-sectional survey included study sites across Europe identified through snowball recruitment. Site co-ordinators (healthcare professionals in emergency and geriatric care) were surveyed online using Microsoft Forms. Items covered department and hospital capacity, frailty and delirium identification methods, staffing, and frailty-focused healthcare services in the ED. Descriptive statistics were reported.
Results
A total of 68 sites from 17 countries participated. Emergency departments had median 30 (IQR 21–53) trolley spaces. Most defined \"older people\" by age 65+ (64%) or 75+ (25%). Frailty screening was used at 69% of sites and mandated at 38%. Night-time staffing was lower compared to day-time for nursing (10 [IQR 8–14] vs. 14 [IQR 10–18]) and physicians (5 [IQR 3–8] vs. 10 [IQR 7–15]). Most sites had provision for ED frailty specialist services by day, but these services were rarely available at night. Sites mostly had accessible facilities; however, hot meals were rarely available at night (18%).
Conclusion
This survey demonstrated variability in case definitions, screening practices, and frailty-attuned service provision. There is no unanimous definition for older age, and while the Clinical Frailty Scale was commonly used, this was rarely mandated or captured in electronic records. Frailty services were often unavailable overnight. Appreciation of the variation in frailty service models could inform operational configuration and workforce development.
Journal Article
Linkages between auditory perception and action: acoustical facilitation of motor responses
In our everyday lives we often have to respond quickly to events in the world around us. This thesis examined whether task-irrelevant, moving auditory stimuli facilitated context-appropriate motor responses. The experiments followed the same general methodology: participants responded to a visual target (a box on the screen) which was sometimes accompanied, or preceded, by a moving broadband auditory stimulus. For the experiments in Chapter 2 the auditory stimulus started in one hemifield and moved to the other. The results indicated motor responses were facilitated when the auditory stimulus was moving azimuthally, to a greater degree than when it was static, but only when the direction of the auditory stimulus was opposite to that of the response (incongruent) and only for Experiment 2. Chapter 3 further examined this facilitation, whilst restricting the movement of the auditory stimuli to either the left or right hemifield. The results indicated facilitation from bi-modal presentations, particularly when responses were towards the hemifield the auditory stimulus was presented in. Experiments 3 - 6 indicated responses were facilitated when the auditory stimulus and the required motor response moved in the same direction. Finally, Chapter 4 utilised looming auditory stimuli to test whether they led to greater facilitation than that observed in Chapter 3. The results indicated looming auditory stimuli facilitated responses relative to receding or static stimuli. There was also facilitation from bimodal presentations over their uni-modal counterparts, particularly when the responses were towards the hemifield the auditory stimulus was presented in. There was facilitation when the auditory stimulus moved in the opposite direction to the required response, compared to static, though only in Experiments 7 and 11. This thesis suggests that motor responses can be facilitated by task-irrelevant, moving, particularly looming, auditory stimuli and may be of benefit in tasks that require quick responses.
Dissertation
Control of 2D plasmons in the topological insulator Bi2Se3 with highly crystalline C60 overlayers
Topological Insulators (TIs) present an interesting materials platform for nanoscale, high frequency devices because they support high mobility, low scattering electronic transport within confined surface states. However, a robust methodology to control the properties of surface plasmons in TIs has yet to be developed. We propose that charge transfer between Bi\\(_2\\)Se\\(_3\\) and crystalline C\\(_{60}\\) films may provide tunable control of the two-dimensional plasmons in Bi\\(_2\\)Se\\(_3\\). We have grown heterostructures of Bi\\(_2\\)Se\\(_3\\)/C\\(_{60}\\) with exceptional crystallinity. Electron energy loss spectroscopy (EELS) reveals significant hybridisation of \\(\\pi\\) states at the interface, despite the expectation for only weak van der Waals interactions, including quenching of 2D plasmons. Momentum-resolved EELS measurements are used to probe the plasmon dispersion, with Density Functional Theory predictions providing an interpretation of results based on interfacial charge dipoles. Our measurements suggest a robust methodology for tuneable TI interfaces that can be engineered for plasmonic applications in computing, communications and sensing.
Paper