1,094 research outputs found
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
Sun Protection Policy in Elementary Schools in Hawaii
INTRODUCTION: Childhood sun exposure is a major risk factor for skin cancer, the most common form of cancer in the United States. Schools in locations that receive high amounts of ultraviolet radiation have been identified as important sites for reducing excessive sun exposure. METHODS: The objective of this study was to determine the prevalence of sun protection policies, environmental features, and attitudes in public elementary schools in Hawaii. Surveys were sent to all (n = 177) public elementary school principals in Hawaii. Non-respondents were called three weeks after the initial mailing. The survey asked about sun protection policies, environmental features, and attitudes toward sun protection. The survey was designed to measure all seven components of Guidelines for School Programs to Prevent Skin Cancer, issued by the Centers for Disease Control and Prevention. RESULTS: Seventy-eight percent of schools responded to the survey. Only one school had a written school policy. Almost all schools (99.3%) scheduled outdoor activities during peak sun hours. School uniforms rarely included long pants (6.5%), long-sleeved shirts (5.1%), or hats (1.5%). Current policies did not support or restrict sun protection habits. Almost one third of those surveyed were in favor of a statewide policy (28.1%), and most believed excessive sun exposure was an important childhood risk (78.9%), even among non-white students (74.5%). CONCLUSION: Results of this study suggest the following: 1) school personnel in Hawaii are concerned about childhood sun exposure; 2) current school policies fail to address the issue; 3) most schools are receptive to developing sun protection policies and programs; and 4) students appear to be at high risk for sun exposure during school hours
Data-parallel agent-based microscopic road network simulation using graphics processing units
Road network microsimulation is computationally expensive, and existing state of the art commercial tools use task parallelism and coarse-grained data-parallelism for multi-core processors to achieve improved levels of performance. An alternative is to use Graphics Processing Units (GPUs) and fine-grained data parallelism. This paper describes a GPU accelerated agent based microsimulation model of a road network transport system. The performance for a procedurally generated grid network is evaluated against that of an equivalent multi-core CPU simulation. In order to utilise GPU architectures effectively the paper describes an approach for graph traversal of neighbouring information which is vital to providing high levels of computational performance. The graph traversal approach has been integrated within a GPU agent based simulation framework as a generalised message traversal technique for graph-based communication. Speed-ups of up to 43 × are demonstrated with increased performance scaling behaviour. Simulation of over half a million vehicles and nearly two million detectors at a rate of 25 × faster than real-time is obtained on a single GPU
On the deflection of asteroids with mirrors
This paper presents an analysis of an asteroid deflection method based on multiple solar concentrators. A model of the deflection through the sublimation of the surface material of an asteroid is presented, with simulation results showing the achievable orbital deflection with, and without, accounting for the effects of mirror contamination due to the ejected debris plume. A second model with simulation results is presented analyzing an enhancement of the Yarkovsky effect, which provides a significant deflection even when the surface temperature is not high enough to sublimate. Finally the dynamical model of solar concentrators in the proximity of an irregular celestial body are discussed, together with a Lyapunov-based controller to maintain the spacecraft concentrators at a required distance from the asteroid
Testing the Assumptions of Stage of Change for Fruit and Vegetable Consumption: A Naturalistic Study
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
Changes in the behavioural determinants of health during the COVID-19 pandemic: gender, socioeconomic and ethnic inequalities in five British cohort studies
BACKGROUND: The COVID-19 pandemic is expected to have far-reaching consequences on population health. We investigated whether these consequences included changes in health-impacting behaviours which are important drivers of health inequalities. METHODS: Using data from five representative British cohorts (born 2000-2002, 1989-1990, 1970, 1958 and 1946), we investigated sleep, physical activity (exercise), diet and alcohol intake (N=14 297). We investigated change in each behaviour (pre/during the May 2020 lockdown), and differences by age/cohort, gender, ethnicity and socioeconomic position (childhood social class, education attainment and adult financial difficulties). Logistic regression models were used, accounting for study design and non-response weights, and meta-analysis used to pool and test cohort differences in association. RESULTS: Change occurred in both directions-shifts from the middle part of the distribution to both declines and increases in sleep, exercise and alcohol use. Older cohorts were less likely to report changes in behaviours while the youngest reported more frequent increases in sleep, exercise, and fruit and vegetable intake, yet lower alcohol consumption. Widening inequalities in sleep during lockdown were more frequent among women, socioeconomically disadvantaged groups and ethnic minorities. For other outcomes, inequalities were largely unchanged, yet ethnic minorities were at higher risk of undertaking less exercise and consuming lower amounts of fruit and vegetables. CONCLUSIONS: Our findings provide new evidence on the multiple changes to behavioural outcomes linked to lockdown, and the differential impacts across generation, gender, socioeconomic circumstances across life, and ethnicity. Lockdown appeared to widen some (but not all) forms of health inequality
Childhood growth and development and DNA methylation age in mid-life
Background: In the first study of its kind, we examine the association between growth and development in early life and DNAm age biomarkers in mid-life. /
Methods: Participants were from the Medical Research Council National Survey of Health and Development (n = 1376). Four DNAm age acceleration (AgeAccel) biomarkers were measured when participants were aged 53 years: AgeAccelHannum; AgeAccelHorvath; AgeAccelLevine; and AgeAccelGrim. Exposure variables included: relative weight gain (standardised residuals from models of current weight z-score on current height, and previous weight and height z-scores); and linear growth (standardised residuals from models of current height z-score on previous height and weight z-scores) during infancy (0–2 years, weight gain only), early childhood (2–4 years), middle childhood (4–7 years) and late childhood to adolescence (7–15 years); age at menarche; and pubertal stage for men at 14–15 years. The relationship between relative weight gain and linear growth and AgeAccel was investigated using conditional growth models. We replicated analyses from the late childhood to adolescence period and pubertal timing among 240 participants from The National Child and Development Study (NCDS). /
Results: A 1SD increase in relative weight gain in late childhood to adolescence was associated with 0.50 years (95% CI 0.20, 0.79) higher AgeAccelGrim. Although the CI includes the null, the estimate was similar in NCDS [0.57 years (95% CI − 0.01, 1.16)] There was no strong evidence that relative weight gain and linear growth in childhood was associated with any other AgeAccel biomarker. There was no relationship between pubertal timing in men and AgeAccel biomarkers. Women who reached menarche ≥ 12 years had 1.20 years (95% CI 0.15, 2.24) higher AgeAccelGrim on average than women who reached menarche < 12 years; however, this was not replicated in NCDS and was not statistically significant after Bonferroni correction. /
Conclusions: Our findings generally do not support an association between growth and AgeAccel biomarkers in mid-life. However, we found rapid weight gain during pubertal development, previously related to higher cardiovascular disease risk, to be associated with older AgeAccelGrim. Given this is an exploratory study, this finding requires replication
Description of Dryocola gen. nov. and two novel species, Dryocola boscaweniae sp. nov. and Dryocola clanedunensis sp. nov. isolated from the rhizosphere of native British oaks
While investigating the role of the rhizosphere in the development of Acute Oak Decline, bacterial strains belonging to the family Enterobacteriaceae were isolated from rhizosphere soil following enrichment for the Enterobacterales. Partial sequencing of several housekeeping genes showed that these strains could not be assigned to an existing genus. Overall, 16 strains were investigated using a polyphasic approach to determine their taxonomic status. This involved phenotypic testing and fatty acid analysis paired with phylogenetic analyses of 16S rRNA and housekeeping gene sequences, as well as phylogenomic analysis of whole genome sequences. Phylogenomic and phylogenetic analyses consistently demonstrated that the 16 isolates could be separated into two distinct clusters in a monophyletic clade situated between the genera Cedecea and Buttiauxella. The two clusters could be genotypically and phenotypically differentiated from each other and from their closest neighbours. As such we propose the description of Dryocola boscaweniae gen. nov. sp. nov. (type strain H6W4T = CCUG 76177T = LMG 32610T) and Dryocola clanedunesis sp. nov. (type strain H11S18T = CCUG 76181T = LMG 32611T)
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