32151 research outputs found
Sort by
Sample size considerations for species co-occurrence models
Get PDFFunding: Natural Environment Research Council (Grant Number(s): NE/S007342/1).Multispecies occupancy models are widely applied to infer interactions in the occurrence of different species, but convergence and estimation issues under realistic sample sizes are common. We conducted a simulation study to evaluate the ability of a recently developed model to recover co-occurrence estimates under varying sample size and interaction scenarios while increasing model complexity in two dimensions: the number of interacting species and the number of covariates. Using both standard and penalized likelihood, we demonstrate that the ability to quantify interactions in species occupancy using this model is highly sensitive to sample size, detection probability, and interaction strength. In the simplest scenario, there is high bias in the interaction parameter (used for co-occurrence inference) with less than 100 sites at high detection, and 400–1000 sites at low detection, depending on interaction strength. Strong co-occurrence is detected consistently above 200 sites with high detection probabilities, but weak co-occurrence is never consistently detected even with 2980 sites. We demonstrate that the mean predictive ability of the co-occurrence model is less affected by sample size, with low bias in derived probabilities at 50 sites. Our results highlight that while occupancy patterns are often robust to sample size limitations, reliable inference about co-occurrence demands substantially larger datasets than many studies currently achieve. We caution the interpretation of model output in small datasets or when co-occurrence is expected to be weak, but show methods are suitable to quantify strong co-occurrence in larger datasets and generate predictions of site occupancy states.Peer reviewe
C. D. Broad on precognitions and John William Dunne
Get PDFC. D. Broad developed three different accounts of time over the course of his career. Emily Thomas (2019) has recently argued that the shift from the first to the second of these was motivated by his engagement with the philosophy of Samuel Alexander. In this paper, I argue that the shift from the second to the third was instigated by Broad’s engagement with precognitive dreams and with the thought of John William Dunne. Furthermore, I argue that fully appreciating Broad’s interest in psychic research in general, and precognitions in particular, is required for understanding the theory of time he defended in the second volume of Examination of McTaggart’s Philosophy. I also argue that interpreting the Examination in light of Broad’s engagement with Dunne can help remove the inconsistencies in Broad’s third account.Peer reviewe
Optimizing ExoMars rover remote sensing multispectral science II : choosing and using multispectral filters for dynamic planetary surface exploration with linear discriminant analysis
Get PDFFunding: RBS, PMG, CRC, and EJA thank the UK Space Agency for support (Grants ST/T001747/1 and ST/Y005910/1). SM acknowledges a UK Science and Technology Facilities Council (STFC) PhD studentship (Grant ST/R504961/1).In this paper we address two problems associated with data-limited dynamic spacecraft exploration: data-prioritization for transmission, and data-reduction for interpretation, in the context of ESA ExoMars rover multispectral imaging. We present and explore a strategy for selecting and combining subsets of spectral channels captured from the ExoMars Panoramic Camera, and attempt to seek hematite against a background of phyllosilicates and basalts as a test case scenario, anticipated from orbital studies of the rover landing site. We compute all available dimension reductions on the material reflectance spectra afforded by 4 spectral parameter types, and consider all possible paired combinations of these. We then find the optimal linear combination of each pair whilst evaluating the resultant target-vs.-background separation in terms of the Fisher Ratio and classification accuracy, using Linear Discriminant Analysis. We find ∼50,000 spectral parameter combinations with a classification accuracy >95% that use 6-or-less filters, and that the highest accuracy score is 99.6% using 6 filters, but that an accuracy of >99% can still be achieved with 2 filters. We find that when the more computationally efficient Fisher Ratio is used to rank the combinations, the highest accuracy is 99.1% using 4 filters, and 95.1% when limited to 2 filters. These findings are applicable to the task of time-constrained planning of multispectral observations, and to the evaluation and cross-comparison of multispectral imaging systems at specific material discrimination tasks.Peer reviewe
Five year mortality in an RCT of a lung cancer biomarker to select people for low dose CT screening
Get PDFFunding: The Scottish Government Health and Social Care Directorate and Oncimmune.The role of biomarkers in risk-based early detection of lung cancer may enable screening to become cost effective and widely accessible. EarlyCDT-Lung is an example of such a blood-based autoantibody biomarker which may improve accessibility to Low dose Computed Tomography (LDCT) screening for those at highest risk. We randomized 12 208 individuals aged 50–75 at high risk of developing lung cancer to either the test or to standard clinical care. Outcomes were ascertained from Register of Deaths and Cancer Registry. Cox proportional hazards models were used to estimate the hazard ratio of the rate of deaths from all causes and lung cancer. Additional analyses were performed for cases of lung cancer diagnosed within two years of the initial test. After 5 years 326 lung cancers were detected (2.7% of those enrolled). The total number of deaths reported from all causes in the intervention group was 344 compared to 388 in the control group. There were 73 lung cancer deaths in the intervention arm and 90 in the controls (Adjusted HR 0.789 (0.636, 0.978). An analysis of cases of lung cancer detected within 2 years of randomization in the intervention group showed that there were 34 deaths from all causes and 29 from lung cancer. In the control group there were 56 deaths with 49 from lung cancer. In those diagnosed with lung cancer within 2 years of randomization the hazard ratio for all cause mortality was 0.615 (0.401,0.942) and for lung cancer 0.598 (0.378, 0.946). Further large-scale studies of the role of biomarkers to target lung cancer screening, in addition to LDCT, are likely to provide additional value.Peer reviewe
The messy art of conversation in practical theology : explorations and reflections
Get PDFUsing autoethnography, the authors (a Muslim woman and a Christian man) reflect on their co-creation of a podcast series, ‘Conversations in Practical Theology’, which they commenced in 2017. Locating the precipitating factors in their experiences of the British and Irish Association for Practical Theology (BIAPT) conference that year, and their respective faith contexts of Islam and Christianity, they test Stephen Pattison’s 2020 proposal that practical theology is fundamentally a practice of conversation. They argue that through encountering one another (and themselves) in podcasting, it is the eclecticism and haphazardness of their intellectual engagement, crucially as representatives of no-one but themselves, that Pattison’s contention of the messiness of good practical theological conversation is upheld.Peer reviewe
The user-centered design of a clinical dashboard and patient-facing app for gestational diabetes
Get PDFFunding: JRK is funded by Medical Research Scotland (PHD-50224-2020). RMR acknowledges the support of the British Heart Foundation (RE/18/5/34216).Background: The number of pregnancies affected by gestational diabetes mellitus (GDM) is growing. With the increased use of smartphones and predictive modeling, a mobile health (mHealth) solution could be developed to improve care and management of GDM while streamlining care through risk stratification. Methods: A user-centered mHealth tool was designed from ethnographic observations and 11 semi-structured interviews (six health care professionals [HCPs] and five women with GDM), followed by iterative changes and evaluation from three feedback groups with 31 participants (17 HCPs, 14 researchers) and 13 questionnaires with women with GDM. Results: “MyGDM” includes a clinical dashboard that centralizes the clinic’s patients, highlighting off-target blood glucose and predicting the need for pharmacological intervention. It is linked with a patient-facing app that includes structured education, culturally inclusive language options, and meal ideas. Through the feedback sessions, iterative changes were made around visualization and patient safety, and participants were positive toward the potential user experience. In the 13 questionnaires with women with GDM, 100% said it would fit into their lifestyle and help them manage GDM. Educational resources and the “request a call” functions were well received with 61.5% (8/13) and 69.2% (9/13) saying they were very likely or likely to use these, respectively. Conclusion: A user-centered mHealth tool consisting of a clinical dashboard linked with a patient-facing app for GDM care and management has been designed. Evaluation of the interactive design by end users was positive and showed that it met their needs.Peer reviewe
Early medieval cremation burials in Atlantic northern Britain
No full textThis discussion outlines the evidence for cremation burials in Atlantic northern Britain, c. 400–1100 CE. It works through the variety of evidence (absolute dating, artefacts, stratigraphy) and touches on the issues associated with each, before moving onto topics such as the selection and deposition of cremated human remains, monument reuse, and the role of trans- and interdisciplinary research. The evidence is more extensive than usually realised, representing a significant portion of the overall dated cremation burials in northern Britain across all periods, demonstrating that what is often regarded as a Bronze Age practice continued down to the end of the first millennium CE. This, in turn raises questions regarding the use of cremation evidence alone to identify intrusive practices associated with settlement from Scandinavia or from among the Scandinavian diaspora in the period c. 800–1000 CE.Peer reviewe
Enhancing the performance of metal-supported solid oxide fuel cells via infiltration with an aqueous solution of metal nitrate salts
Get PDFFunding: The Natural Sciences and Engineering Research Council of Canada (NSERC) have supported this work through Alliance grants to one of us (Venkataraman Thangadurai). This work was also financially supported by the Nissan Motor Corporation Limited via Nissan Technical Centre North America.The infiltration technique is a cost-effective method to develop nanostructured electrodes that can accelerate sluggish oxygen reduction reaction (ORR) and enhance the electrochemical performance of solid oxide fuel cells (SOFCs) at intermediate temperatures (600–800 °C). For metal-supported SOFCs, identifying a highly efficient ORR catalyst is an ongoing challenge due to lower temperature operation. In this work, nanostructured praseodymium oxide (PrOx) and multiphase heterostructures containing perovskites with the nominal composition of Nd0.6Sr0.4CoO3−δ (NSC), SrCO3, and CoO have been developed via infiltration into the symmetric metal-supported backbone as binary layer composite, and their electrochemical performance has been investigated. The composite demonstrates enhanced electrochemical performance at various temperatures achieving the lowest polarization resistance (Rp) of 0.05 Ω cm2 at 700 °C compared to multiphase NSC alone (0.1 Ω cm2) under similar conditions. A distribution function of relaxation time (DFRT) analysis using impedance spectroscopy genetic program (ISGP) was carried out to study different electrochemical processes. PrOx significantly improves the processes involved in the ORR. The full cell performance of the composite electrode achieves a peak power density (PPD) of 329 mW·cm–2 at 700 °C in 3%H2O/H2 as fuel.Peer reviewe
Planetary waves drive horizontal variations in trace species in the Venus deep atmosphere
Get PDFFunding: The authors are deeply grateful to the UK Science and Technology Facilities Council for funding support in the form of STFC grant ST/X001180/1.The deep atmosphere of Venus remains mysterious because of the planet's high, optically thick cloud decks. While phenomena such as the observed decadal fluctuations in sulfur dioxide abundance above the clouds could shed light on conditions below, poor understanding of vertical and horizontal transport limits such an approach. Nightside spectral windows permit observation of trace gas species in the lower atmosphere, but incomplete understanding of the circulation makes the distribution of these species challenging to interpret. We performed two simulations with the Venus Planetary Climate Model including an age of air calculation to investigate tracer transport (a) between the surface and the stagnant lower haze layer and (b) between the cloud deck and the observable upper atmosphere. We find a timescale on the order of many decades for surface-to-lower haze layer transport and ∼1.4 yr from the lowest cloud deck to 101 km. The extreme slowness of transport from the surface to the clouds makes it unlikely that compositional variability at the surface could affect the upper atmosphere sulfur dioxide abundance on observed timescales. Planetary-scale Rossby waves with a zonal wavenumber of 1 in both hemispheres are found to circumnavigate the planet in the deep atmosphere in 36 Earth days. These waves are associated with gyres that collect tracers and areas of upwelling that transport them to higher altitudes, leading to significantly younger air at polar latitudes in the altitude range of 25–45 km. The existence of chemically enhanced traveling Rossby gyres could explain the observed deep atmosphere carbon monoxide variability.Peer reviewe
In-operando investigation of Purcell effect on efficiency roll-off in top-emitting phosphorescent organic light emitting diodes
Get PDFFunding: The authors are grateful to the Engineering and Physical Sciences Research Council for support from grants EP/R035164 and EP/Y037243/01.Efficiency roll-off is a major issue for applications of organic light emitting diodes (OLEDs) that require high brightness. The underlying processes leading to efficiency roll-off in phosphorescent OLEDs include triplet-polaron (TPA) and triplet-triplet annihilation (TTA). Hence, decreasing the triplet exciton lifetime by enhancing radiative decay rates can be an effective method to manage efficiency roll-off in phosphorescent OLEDs. Here we use in-operando measurement to study the Purcell effect and engineer efficiency roll-off. By changing the cavity parameters and measuring electroluminescence (EL) and photoluminescence (PL) on operating devices, we find that devices with higher Purcell factor have a smaller efficiency roll-off, suggesting a route to improve the performance of OLEDs in high brightness applications.Peer reviewe
Access Repository Dashboard
Do you manage St Andrews Research Repository? Access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard!