Assessing the Viability of Complex Electrical Impedance Tomography (EIT) with a Spatially Distributed Sensor Array for Imaging of River Bed Morphology: a Proof of Concept (Study)

This report was produced as part of a NERC funded ‘Connect A’ project to establish a new collaborative partnership between the University of Worcester (UW) and Q-par Angus Ltd. The project aim was to assess the potential of using complex Electrical Impedance Tomography (EIT) to image river bed morphology. An assessment of the viability of sensors inserted vertically into the channel margins to provide real-time or near real-time monitoring of bed morphology is reported. Funding has enabled UW to carry out a literature review of the use of EIT and existing methods used for river bed surveys, and outline the requirements of potential end-users. Q-par Angus has led technical developments and assessed the viability of EIT for this purpose. EIT is one of a suite of tomographic imaging techniques and has already been used as an imaging tool for medical analysis, industrial processing and geophysical site survey work. The method uses electrodes placed on the margins or boundary of the entity being imaged, and a current is applied to some and measured on the remaining ones. Tomographic reconstruction uses algorithms to estimate the distribution of conductivity within the object and produce an image of this distribution from impedance measurements. The advantages of the use of EIT lie with the inherent simplicity, low cost and portability of the hardware, the high speed of data acquisition for real-time or near real-time monitoring, robust sensors, and the object being monitored is done so in a non-invasive manner. The need for sophisticated image reconstruction algorithms, and providing images with adequate spatial resolution are key challenges. A literature review of the use of EIT suggests that to date, despite its many other applications, to the best of our knowledge only one study has utilised EIT for river survey work (Sambuelli et al 2002). The Sambuelli (2002) study supported the notion that EIT may provide an innovative way of describing river bed morphology in a cost effective way. However this study used an invasive sensor array, and therefore the potential for using EIT in a non-invasive way in a river environment is still to be tested. A review of existing methods to monitor river bed morphology indicates that a plethora of techniques have been applied by a range of disciplines including fluvial geomorphology, ecology and engineering. However, none provide non-invasive, low costs assessments in real-time or near real-time. Therefore, EIT has the potential to meet the requirements of end users that no existing technique can accomplish. Work led by Q-par Angus Ltd. has assessed the technical requirements of the proposed approach, including probe design and deployment, sensor array parameters, data acquisition, image reconstruction and test procedure. Consequently, the success of this collaboration, literature review, identification of the proposed approach and potential applications of this technique have encouraged the authors to seek further funding to test, develop and market this approach through the development of a new environmental sensor

Predictivity of in vitro non-clinical cardiac contractility assays for inotropic effects in humans – A Literature Search

Adverse drug effects on the cardiovascular system is a major cause of compound attrition throughout compound discovery and development. There are many ways by which drugs can affect the cardiovascular system, including effects on the electrocardiogram, vascular resistance, heart rate and the force of contraction of the heart (inotropy). Compounds that increase the force of contraction of the heart can be harmful in patients with ischemic heart disease, whilst negative inotropes can induce symptoms of heart failure. There is a range of non-clinical in vitro and in vivo assays used to detect inotropic effects of drugs. We have conducted a literature review of the in vitro assays and compared the findings from these with known effects on cardiac contractility in man. There was a wide variety of assays used, ranging from perfuse whole hearts to isolated regions of the heart (papillary muscle, ventricle and atria), which were removed from a number of species (cat, guinea pig, rabbit and rat). We conducted two analyses. The first was investigating the concordance of the findings from the in vitro assays at any concentration with those observed in man (an assessment of hazard identification) and the second was the concordance of the in vitro findings at concentrations tested up to 10-fold higher than those tested in the clinic. We found that when used as a hazard identification tool, the available assays had good sensitivity (88%), although the specificity was not so good (60%), but when used as a risk management tool the sensitivity was considerable reduced (sensitivity 58 -70% and specificity 60%).These data would suggest that the available in vitro assays can be used as hazard identification tools for adverse drug effects on cardiac contractility, but there is a need for new assays to better predict the exposures in man that may cause a change in cardiac contractility and therefore better predict the likely therapeutic index of compounds prior to nomination of compounds for clinical development

Prehospital critical care is associated with increased survival in adult trauma patients in Scotland

Background Scotland has three prehospital critical care teams (PHCCTs) providing enhanced care support to a usually paramedic-delivered ambulance service. The effect of the PHCCTs on patient survival following trauma in Scotland is not currently known nationally. Methods National registry-based retrospective cohort study using 2011-2016 data from the Scottish Trauma Audit Group. 30-day mortality was compared between groups after multivariate analysis to account for confounding variables. Results Our data set comprised 17 157 patients, with a mean age of 54.7 years and 8206 (57.5%) of male gender. 2877 patients in the registry were excluded due to incomplete data on their level of prehospital care, leaving an eligible group of 14 280. 13 504 injured adults who received care from ambulance clinicians (paramedics or technicians) were compared with 776 whose care included input from a PHCCT. The median Injury Severity Score (ISS) across all eligible patients was 9; 3076 patients (21.5%) met the ISS>15 criterion for major trauma. Patients in the PHCCT cohort were statistically significantly (all p < 0.01) more likely to be male; be transported to a prospective Major Trauma Centre; have suffered major trauma; have suffered a severe head injury; be transported by air and be intubated prior to arrival in hospital. Following multivariate analysis, the OR for 30-day mortality for patients seen by a PHCCT was 0.56 (95% CI 0.36 to 0.86, p=0.01). Conclusion Prehospital care provided by a physician-led critical care team was associated with an increased chance of survival at 30 days when compared with care provided by ambulance clinicians

Impact of body size, nutrition and socioeconomic position in early life on the epigenome: a systematic review protocol

BACKGROUND: Body size, nutrition and socioeconomic position (SEP) in early life have been associated with a range of later life health outcomes. Epigenetic regulation is one mechanism through which these early life factors may impact later life health. The aim of this review protocol is to outline procedures to document the influence of body size, nutrition and SEP in early life on the epigenome. METHODS: MEDLINE, Embase and BIOSIS will be systematically searched using pre-defined keywords. Additional studies will be identified through manual searching of reference lists. Two independent researchers will assess the eligibility and quality of each study, with disagreements being resolved through discussion or a third reviewer. Studies will be included if they have epigenetic markers measured either at the same time as, or after, the early life exposure and, have a measure of body size, nutrition or SEP in early life (up to 12 years), are in the English language and are from a sample of community-dwelling participants. DISCUSSION: This protocol will be used to collate the evidence for the effect of early life factors on the epigenome. Findings will form a component of a wider research study examining epigenetic responses to exposures in early life and over the life course and its impact on healthy ageing using data from population-based cohort studies. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42016050193

A Standardised Benchmark for Assessing the Performance of Fixed Radius Near Neighbours

Many agent based models require agents to have an awareness of their local peers. The handling of these fixed radius near neighbours (FRNNs) is often a limiting factor of performance. However without a standardised metric to assess the handling of FRNNs, contributions to the field lack the rigorous appraisal necessary to expose their relative benefits. This paper presents a standardised specification of a multi agent based benchmark model. The benchmark model provides a means for the objective assessment of FRNNs performance, through the comparison of implementations. Results collected from implementations of the benchmark model under three agent based modelling frameworks show the 64-bit floating point performance of each framework to scale linearly with agent population, in contrast the GPU accelerated framework’s 32- bit floating point performance only became linear after maximal device utilisation around 100,000 agent

Mirror formation control in the vicinity of an asteroid

Two strategies are presented for the positioning and control of a spacecraft formation designed to focus sunlight onto a point on the surface of asteroid, thereby sublimating the material and ejecting debris creating thrust. In the first approach, the formation is located at artficial equilibrium points around the asteroid and controlled using the force from the solar radiation pressure. The second approach determines the optimal periodic formation orbits, subject to the gravitational perturbations from the asteroid, the solar radiation pressure and the control acceleration derived from a control law

The impact of the Lombard effect on audio and visual speech recognition systems

When producing speech in noisy backgrounds talkers reflexively adapt their speaking style in ways that increase speech-in-noise intelligibility. This adaptation, known as the Lombard effect, is likely to have an adverse effect on the performance of automatic speech recognition systems that have not been designed to anticipate it. However, previous studies of this impact have used very small amounts of data and recognition systems that lack modern adaptation strategies. This paper aims to rectify this by using a new audio-visual Lombard corpus containing speech from 54 different speakers – significantly larger than any previously available – and modern state-of-the-art speech recognition techniques. The paper is organised as three speech-in-noise recognition studies. The first examines the case in which a system is presented with Lombard speech having been exclusively trained on normal speech. It was found that the Lombard mismatch caused a significant decrease in performance even if the level of the Lombard speech was normalised to match the level of normal speech. However, the size of the mismatch was highly speaker-dependent thus explaining conflicting results presented in previous smaller studies. The second study compares systems trained in matched conditions (i.e., training and testing with the same speaking style). Here the Lombard speech affords a large increase in recognition performance. Part of this is due to the greater energy leading to a reduction in noise masking, but performance improvements persist even after the effect of signal-to-noise level difference is compensated. An analysis across speakers shows that the Lombard speech energy is spectro-temporally distributed in a way that reduces energetic masking, and this reduction in masking is associated with an increase in recognition performance. The final study repeats the first two using a recognition system training on visual speech. In the visual domain, performance differences are not confounded by differences in noise masking. It was found that in matched-conditions Lombard speech supports better recognition performance than normal speech. The benefit was consistently present across all speakers but to a varying degree. Surprisingly, the Lombard benefit was observed to a small degree even when training on mismatched non-Lombard visual speech, i.e., the increased clarity of the Lombard speech outweighed the impact of the mismatch. The paper presents two generally applicable conclusions: i) systems that are designed to operate in noise will benefit from being trained on well-matched Lombard speech data, ii) the results of speech recognition evaluations that employ artificial speech and noise mixing need to be treated with caution: they are overly-optimistic to the extent that they ignore a significant source of mismatch but at the same time overly-pessimistic in that they do not anticipate the potential increased intelligibility of the Lombard speaking style

Accessing Sodium Ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands : structural, synthetic, and magnetic insights

This study reports the synthesis and single-crystal X-ray crystallographic, NMR spectroscopic, and magnetic characterization of a series of sodium ferrates using bis(amide) Fe(HMDS)2 as a precursor (HMDS = 1,1,1,3,3,3-hexamethyldisilazide). Reaction with sodium reagents NaHMDS and NaCH2SiMe3 in hexane afforded donor-solvent-free sodium ferrates [{NaFe(HMDS)3}∞] (1) and [{NaFe(HMDS)2(CH2SiMe3)}∞] (2), respectively, which exhibit contacted ion pair structures, giving rise to new polymeric chain arrangements made up of a combination of inter- and intramolecular Na···Me(HMDS) electrostatic interactions. Addition of the unsaturated NHC IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) to 1 and 2 caused deaggregation of their polymeric structures to form discrete NHC-stabilized solvent-separated ion pairs [Na(IPr)2]+[Fe(HMDS)3]- (3) and [(THF)3·NaIPr]+[Fe(HMDS)2CH2SiMe3]- (4), where in both cases, the NHC ligand coordinates preferentially to Na. In contrast, when IPr is sequentially reacted with the single-metal reagents NaCH2SiMe3 and Fe(HMDS)2, the novel heteroleptic ferrate (THF)3Na[:C{[N(2,6-iPr2C6H3)]2CHCFe(HMDS)2}] (5) is obtained. This contains an anionic NHC ligand acting as an unsymmetrical bridge between the two metals, coordinating through its abnormal C4 position to Fe and its normal C2 position to Na. The formation of 5 can be described as an indirect ferration process where IPr is first metalated at the C4 position by the polar sodium alkyl reagent, which in turn undergoes transmetalation to the more electronegative Fe(HMDS)2 fragment. Treatment of 5 with 1 molar equiv of methyl triflate (MeOTf) led to the isolation and structural elucidation of the neutral abnormal NHC (aNHC) tricoordinate iron complex [CH3C{[N(2,6-iPr2C6H3)]2CHCFe(HMDS)2}] (6) with the subsequent elimination of NaOTf, disclosing the selectivity of complex 5 to react with this electrophile via its C2 position, leaving its Fe-C4 and Fe-N bonds intact. The magnetic susceptibility properties of compounds 1-6 have been examined. This study revealed a drastic change of magnetic susceptibility in replacing a pure σ donor from an idealized trigonal coordination environment by an NHC π donating character

Level Sets of the Takagi Function: Local Level Sets

The Takagi function \tau : [0, 1] \to [0, 1] is a continuous non-differentiable function constructed by Takagi in 1903. The level sets L(y) = {x : \tau(x) = y} of the Takagi function \tau(x) are studied by introducing a notion of local level set into which level sets are partitioned. Local level sets are simple to analyze, reducing questions to understanding the relation of level sets to local level sets, which is more complicated. It is known that for a "generic" full Lebesgue measure set of ordinates y, the level sets are finite sets. Here it is shown for a "generic" full Lebesgue measure set of abscissas x, the level set L(\tau(x)) is uncountable. An interesting singular monotone function is constructed, associated to local level sets, and is used to show the expected number of local level sets at a random level y is exactly 3/2.Comment: 32 pages, 2 figures, 1 table. Latest version has updated equation numbering. The final publication will soon be available at springerlink.co