Dynamic Data Structures for Document Collections and Graphs

In the dynamic indexing problem, we must maintain a changing collection of text documents so that we can efficiently support insertions, deletions, and pattern matching queries. We are especially interested in developing efficient data structures that store and query the documents in compressed form. All previous compressed solutions to this problem rely on answering rank and select queries on a dynamic sequence of symbols. Because of the lower bound in [Fredman and Saks, 1989], answering rank queries presents a bottleneck in compressed dynamic indexing. In this paper we show how this lower bound can be circumvented using our new framework. We demonstrate that the gap between static and dynamic variants of the indexing problem can be almost closed. Our method is based on a novel framework for adding dynamism to static compressed data structures. Our framework also applies more generally to dynamizing other problems. We show, for example, how our framework can be applied to develop compressed representations of dynamic graphs and binary relations

A novel method of non-clinical dispatch is associated with a higher rate of critical Helicopter Emergency Medical Service intervention

Background - Helicopter Emergency Medical Services (HEMS) are a scarce resource that can provide advanced emergency medical care to unwell or injured patients. Accurate tasking of HEMS is required to incidents where advanced pre-hospital clinical care is needed. We sought to evaluate any association between non-clinically trained dispatchers, following a bespoke algorithm, compared with HEMS paramedic dispatchers with respect to incidents requiring a critical HEMS intervention. Methods - Retrospective analysis of prospectively collected data from two 12-month periods was performed (Period one: 1st April 2014 – 1st April 2015; Period two: 1st April 2016 – 1st April 2017). Period 1 was a Paramedic-led dispatch process. Period 2 was a non-clinical HEMS dispatcher assisted by a bespoke algorithm. Kent, Surrey & Sussex HEMS (KSS HEMS) is tasked to approximately 2500 cases annually and operates 24/7 across south-east England. The primary outcome measure was incidence of a HEMS intervention.Results - A total of 4703 incidents were included; 2510 in period one and 2184 in period two. Variation in tasking was reduced by introducing non-clinical dispatchers. There was no difference in median time from 999 call to HEMS activation between period one and two (period one; median 7 min (IQR 4–17) vs period two; median 7 min (IQR 4–18). Non-clinical dispatch improved accuracy of HEMS tasking to a mission where a critical care intervention was required (OR 1.25, 95% CI 1.04–1.51, p = 0.02).Conclusion - The introduction of non-clinical, HEMS-specific dispatch, aided by a bespoke algorithm improved accuracy of HEMS tasking. Further research is warranted to explore where this model could be effective in other HEMS services.Peer reviewedFinal Published versio

Electrophysiological indices of information processing in psychopathy

Psychopathy is a severe personality disorder associated with a range of affective, interpersonal, and behavioural abnormalities. Evidence suggests that psychopaths show marked deficits in processing emotional information, although it is unclear whether they also show more general deficits in error monitoring, attention allocation and response control. It is also unclear whether any variation in neurophysiological performance is also reflected in subclinical populations. In this thesis, event-related potentials (ERPs) were used to examine these issues and involved two separate samples. The first included incarcerated offenders with a range of scores on the Hare Psychopathy Checklist –Revised (PCL-R) and non-offender (staff) controls. The second included a large group of healthy undergraduate males with a full range on scores on the Self-Report Psychopathy Scale (SRP-III). Error monitoring was examined in both samples using a standard letter-flanker task and a modified version of the task in which faces with angry or fearful expressions were used instead of the usual letter stimuli. In general, psychopathy in both samples was associated with attenuated ERN amplitudes on the face flanker task only. Source modeling of the ERN indicated that, while the ERN is generally modeled as having a dipole in the ACC, the psychopath group showed no evidence of ACC activity in this region in conjunction with face-flanker errors. These data suggest that the affect-based neurophysiological deficits associated with psychopathy in the clinical range are observed in a graduated fashion among subclinical samples. Inhibitory control processes were also examined in the incarcerated group using the inhibitory N2 and anteriorized P3 as indices of inhibitory processes evident in correctly withholding prepotent response tendencies on a Go-NoGo task. Despite the common assumption that poor inhibitory control is a central aspect of psychopathy, there was no sign that those at higher levels of psychopathy showed any inhibitory control problems and they produced a robust NoGo N2 and P3. In fact, there were signs that the incarcerated offenders who were low on psychopathy were more likely to produce diminished inhibitory-related components. Finally, years of controversy regarding attention allocation deficits in psychopathy was addressed by collecting standard P3 components during a traditional visual oddball task in the university sample. Behavioural response and P3 amplitudes were unrelated to psychopathy. However, consistent with data from incarcerated samples, higher scores on psychopathy were associated with larger amplitude P2 and N5 responses to target relative to nontarget stimuli, again suggesting some continuity with respect to a distinct, although not necessarily deficient, attentional style at subclinical levels of psychopathy. In general, across these four data sets, the only clear evidence of impaired processing involved a reduced error-monitoring response during the face-flanker task when emotional stimuli formed the basis of the required discrimination and this reduced response was found to vary with the degree of psychopathy even within a subclinical range. These findings support a model of psychopathy involving limbic and paralimbic structures rather than a general reduction in neural function affecting error monitoring, attention allocation and response control

Joint Impact Assessment of CTA's support to CaFAN (2004-2012)

The Caribbean Farmers Network Inc. (CaFAN) is a registered not-for-profit organisation representing about 500,000 small-scale farmers in 15 Caribbean countries. The organisation’s secretariat is located in Kingstown, St. Vincent and the Grenadines. CaFAN conducted this joint impact study, commissioned by the Technical Centre for Agricultural and Rural Cooperation (CTA), to examine in-depth the impact of CTA funding and programme support to CaFAN. The findings are to contribute to learning for development impact within CTA and its ACP partner organisations and networks

Noise Reduction Through Circulation Control

Circulation control technology uses tangential blowing around a rounded trailing edge or a leading edge to change the force and moment characteristics of an aerodynamic body. This technology has been applied to circular cylinders, wings, helicopter rotors, and even to automobiles for improved aerodynamic performance. Only limited research has been conducted on the acoustic of this technology. Since wing flaps contribute to the environmental noise of an aircraft, an alternate blown high lift system without complex mechanical flaps could prove beneficial in reducing the noise of an approaching aircraft. Thus, in this study, a direct comparison of the acoustic characteristics of high lift systems employing a circulation control wing configuration and a conventional wing flapped configuration has been made. These results indicate that acoustically, a circulation control wing high lift system could be considerably more acceptable than a wing with conventional mechanical flaps

The use and impact of 12-lead electrocardiograms in acute stroke patients : a systematic review

BACKGROUND: Stroke is a leading cause of mortality and disability across the globe. Emergency Medical Services assess and transport a large number of these patients in the prehospital setting. Guidelines for UK ambulance services recommend recording a 12-lead electrocardiogram in the prehospital environment, providing this does not add to significant delay in transporting the patient to hospital; however, this recommendation is not based on any evidence. METHODS: A systematic review was conducted to search and synthesise the literature surrounding the use of prehospital electrocardiograms in acute stroke patients, focusing on the prevalence of abnormalities and their association with prognosis and outcome. Online databases, references from selected articles and hand searches were made to identify eligible studies. Two authors independently reviewed the studies to ensure eligibility criteria were met. Main outcomes were presence of abnormality on electrocardiogram, mortality and disability. No studies set in the prehospital environment were found by the search; therefore the eligibility criteria were widened to include hospital-based studies. A total of 18 studies were subsequently included in the review. RESULTS: Although the prevalence of electrocardiogram abnormalities appears common in hospitalised patients, their prognostic impact on mortality, disability and other adverse outcomes is conflicting amongst the literature. There is a lack of research surrounding the use of prehospital electrocardiogram in acute stroke patients. CONCLUSION: Future studies should be based in the prehospital environment and should investigate whether undertaking an electrocardiogram in the prehospital setting affects clinical management decisions or has an association with mortality or morbidity

First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates : An Analysis of the Microbiota

Acknowledgments The authors would like to thank the parents who consented to provide samples with limited notice at an emotional and stressful time. This work was supported entirely from personal donations to the neonatal endowments fund at Aberdeen Maternity Hospital and we thank families for their continued generosity, year-on-year. The Rowett Institute of Nutrition and Health receives funding from the Scottish Government (SG-RESAS). Funding: This work was funded from NHS Grampian Neonatal Endowments. The Rowett Institute receives funding from the Rural and Environmental Science and Analytical Services programme of the Scottish Government. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Using mixtures of biological samples as process controls for RNA-sequencing experiments

Bland-Altman log-ratio(M) - log average (A) plots comparing gene expression in BLM-1 to BLM-2, which were mixed with a designed ratio of 1:1 brain RNA, 2:1 muscle RNA and 1:2 liver RNA. Points representing gene expression values for genes expressed at 5-fold greater levels in a specific tissue are colored based on the tissue in which they are selectively expressed. Non-tissue selective RNA are omitted for clarity. Library size normalization scales all libraries to a common total number of counts, while upper quartile normalization scales to the 75th percentile of the counts for each library. None of these normalizations accurately reflects the designed ratio of transcripts between samples. (PNG 473 kb

Caffeine and attentional control:improved and impaired performance in healthy older adults and Parkinson’s disease according to task demands

INTRODUCTION: Caffeine is frequently consumed to boost goal-directed attention. These procognitive effects may occur due to the adenosine-mediated enhancement of monoamines, such as dopamine, after caffeine administration. As such, caffeine’s beneficial effects may be altered in conditions such as Parkinson’s disease (PD). However, whether caffeine improves cognition, and at what cost, has not been experimentally established in patients with neurodegenerative disease. METHODS: Single-dose trials to probe cognitive effects of caffeine are often confounded by short-term caffeine abstinence which conflates caffeine’s effects with treatment of withdrawal. Using a placebo controlled, blinded, randomised trial design, we assessed the effect of 100 mg of caffeine across well-established tasks (Choice reaction time, Stroop Task and Rapid Serial Visual Presentation Task; RSVP) that probe different aspects of attention in PD patients (n = 24) and controls (n = 44). Critically, participants withdrew from caffeine for a week prior to testing to eliminate the possibility that withdrawal reversal explained any cognitive benefit. RESULTS: Caffeine administration was found to reduce the overall number of errors in patients and controls on the Stroop (p = .018, η(2)(p) = .086) and Choice reaction time (p < . 0001, η(2)(p) = .588) tasks, but there was no specific effect of caffeine on ignoring irrelevant information in the Stroop task. On the RSVP task, caffeine improved dual item accuracy (p = .037) but impaired single item accuracy (p = .044). Across all tasks, there was little evidence that caffeine has different effects in PD participants and controls. CONCLUSION: When removing withdrawal effects as a factor, we demonstrate caffeine has beneficial effects on selective attention but is a double-edge sword for visual temporal attention and would need careful targeting to be clinically useful. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00213-021-06054-9