Small unmanned aerial model accuracy for photogrammetrical fluvial bathymetric survey

Fluvial systems offer a challenging and varied environment for topographic survey, displaying a rapidly varying morphology, vegetation assemblage and degree of submergence. Traditionally theodolite or GPS based systems have been used to capture cross-section and breakline based topographic data which has subsequently been interpolated. Advances in survey technology has resulted in an improved ability to capture larger volumes of information with infrared terrestrial and aerial LiDAR systems capturing high density (<0.02 m) point data across terrestrial surfaces. The rise of Structure from Motion (SfM) photogrammetry, coupled with small unmanned aerial vehicles (sUAV), has potential to record elevation data at reach scale sub decimetre density. The approach has the additional advantage over LiDAR of seeing through clear water to capture bed detail, whilst also generating ortho-rectified photographic mosaics of the survey reach. However, data accuracy has yet to be comprehensively assessed. Here we present a survey protocol for sUAV deployment and provide a reach scale comparison between a theodolite and SfM sUAV survey on the River Sprint, Kendal, the River Ehen at Egremont, England and the Afon Elwy, at Llanfair Talhaiarn, Wales. Comparative analysis between theodolite survey and SfM suggest similar accuracy and precision across terrestrial surfaces with error lowest over solid surfaces, increasing with vegetation complexity. Submerged SfM data, captured bed levels generally to within ±0.25 m with only a weak relationship recorded between error and flow depth. Significantly, associated error when linked to channel D50 highlights the ability of unmanned aerial vehicles to capture accurate fluvial data across a range of river biotopes and depths to 2.4 m

Discovery of novel heart rate-associated loci using the Exome Chip

Resting heart rate is a heritable trait, and an increase in heart rate is associated with increased mortality risk. Genome-wide association study analyses have found loci associated with resting heart rate, at the time of our study these loci explained 0.9% of the variation. This study aims to discover new genetic loci associated with heart rate from Exome Chip meta-analyses. Heart rate was measured from either elecrtrocardiograms or pulse recordings. We meta-analysed heart rate association results from 104 452 European-ancestry individuals from 30 cohorts, genotyped using the Exome Chip. Twenty-four variants were selected for follow-up in an independent dataset (UK Biobank, N = 134 251). Conditional and gene-based testing was undertaken, and variants were investigated with bioinformatics methods. We discovered five novel heart rate loci, and one new independent low-frequency non-synonymous variant in an established heart rate locus (KIAA1755). Lead variants in four of the novel loci are non-synonymous variants in the genes C10orf71, DALDR3, TESK2 and SEC31B. The variant at SEC31B is significantly associated with SEC31B expression in heart and tibial nerve tissue. Further candidate genes were detected from long-range regulatory chromatin interactions in heart tissue (SCD, SLF2 and MAPK8). We observed significant enrichment in DNase I hypersensitive sites in fetal heart and lung. Moreover, enrichment was seen for the first time in human neuronal progenitor cells (derived from embryonic stem cells) and fetal muscle samples by including our novel variants. Our findings advance the knowledge of the genetic architecture of heart rate, and indicate new candidate genes for follow-up functional studies

Abstracts from the NIHR INVOLVE Conference 2017

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Geomorphological effectiveness and maintenance of a riffle-pool sequence

Riffle-pool sequences in gravel-bed rivers provide the template for a number ol fish and invertebrate habitats and their morphological complexities create spatial hydraulic variation over the flow regime that is logistically impossible to measure completely in the field. The mechanisms responsible for riffle-pool maintenance are unclear and despite contributions from many researchers, no conclusive explanation has been developed. There is much debate over the popular velocity reversal hypothesis, where it is generally acknowledged that at low flows the maximum bed shear stress in the channel occurs across the riffle, but at higher less frequent flows areas of maximum bed shear stress can switch to the pool. Sediment interactions control fluvial forms and processes, as such specific analysis of spatial hydraulic patterns in boundary shear stress are required to aid understanding of riffle-pool system behaviour and gain the insight in to the transport capacity that can scour sediment deposited in the predominandy low energy, lower competence pools and thereby provide a mechanism for maintenance ol riffle-pool morphology. Terrestrial LiDAR captures reach scale topographical data to yield a 0.02 m digital elevation model and provides input to three-dimensional computation fluid dynamics software (CFD), where the spatial distribution and area! extent of bed shear stress, surface flow velocities and potential sediment entrainment over the discharge range are investigated for a 188 m gravel-bed reach of Kingsdale Beck, UK. With increasing discharge, spatial distributions of shear stress are revealed, which, until now, have been largely overlooked using previous cross-sectional analysis, highlighting the influence of pool tails as discharge rises. Results show some agreement with past literature on reversal with higher shear stress zones associated with riffles. As discharge increases pools are shown to become more dominant, however the existence of multiple reversals shows that while reversals do occur, they may be short-lived and marginal in magnitude, providing inherent problems with current theory. The overall temporal maintenance of the riffle-pool sequence is more explicitly linked with the long term flow regime, with the flows responsible for moving pool sediment closely confined to near bankfull discharge. Results indicate that potential to entrain sediment from pools occurs only from 85% bankfull. Discharges less than 85% bankfull are suggested to be responsible for maintaining the riffle-pool morphology through flow routing and bed shear stress reversal, however, they are not capable of potentially entraining sediment from the deepest pools. Combined CFD simulations with temporal discharge dominance derived from triangulated rainfall and the Revitalised FSR/FEH rainfallrunoff methodology, highlight the role of rarer more extreme flows in terms of explaining sediment entrainment from pools. At high flow Kingsdale Beck creates a competent sub channel, where a continuous sinuous channel with higher levels of bed shear stress develop with embryonic lateral bars, increasing potential sediment entrainment following the line of thalweg. As flow velocity decreases conventional rifflepool hydromorphology re-establishes and provides a new proposal for the maintenance of a riffle-pool sequence.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Discovery of novel heart rate-associated loci using the Exome Chip

Resting heart rate is a heritable trait, and an increase in heart rate is associated with increased mortality risk. Genome-wide association study analyses have found loci associated with resting heart rate, at the time of our study these loci explained 0.9% of the variation. This study aims to discover new genetic loci associated with heart rate from Exome Chip meta-analyses. Heart rate was measured from either elecrtrocardiograms or pulse recordings. We meta-analysed heart rate association results from 104 452 European-ancestry individuals from 30 cohorts, genotyped using the Exome Chip. Twenty-four variants were selected for follow-up in an independent dataset (UK Biobank, N = 134 251). Conditional and gene-based testing was undertaken, and variants were investigated with bioinformatics methods.We discovered five novel heart rate loci, and one new independent low-frequency non-synonymous variant in an established heart rate locus (KIAA1755). Lead variants in four of the novel loci are non-synonymous variants in the genes C10orf71, DALDR3, TESK2 and SEC31B. The variant at SEC31B is significantly associated with SEC31B expression in heart and tibial nerve tissue. Further candidate genes were detected from long-range regulatory chromatin interactions in heart tissue (SCD, SLF2 and MAPK8). We observed significant enrichment in DNase I hypersensitive sites in fetal heart and lung. Moreover, enrichment was seen for the first time in human neuronal progenitor cells (derived from embryonic stem cells) and fetal muscle samples by including our novel variants.Our findings advance the knowledge of the genetic architecture of heart rate, and indicate new candidate genes for follow-up functional studies

Discovery of novel heart rate-associated loci using the Exome Chip

Resting heart rate is a heritable trait, and an increase in heart rate is associated with increased mortality risk. Genome-wide association study analyses have found loci associated with resting heart rate, at the time of our study these loci explained 0.9% of the variation. This study aims to discover new genetic loci associated with heart rate from Exome Chip meta-analyses. Heart rate was measured from either elecrtrocardiograms or pulse recordings. We meta-analysed heart rate association results from 104 452 European-ancestry individuals from 30 cohorts, genotyped using the Exome Chip. Twenty-four variants were selected for follow-up in an independent dataset (UK Biobank, N = 134 251). Conditional and gene-based testing was undertaken, and variants were investigated with bioinformatics methods.We discovered five novel heart rate loci, and one new independent low-frequency non-synonymous variant in an established heart rate locus (KIAA1755). Lead variants in four of the novel loci are non-synonymous variants in the genes C10orf71, DALDR3, TESK2 and SEC31B. The variant at SEC31B is significantly associated with SEC31B expression in heart and tibial nerve tissue. Further candidate genes were detected from long-range regulatory chromatin interactions in heart tissue (SCD, SLF2 and MAPK8). We observed significant enrichment in DNase I hypersensitive sites in fetal heart and lung. Moreover, enrichment was seen for the first time in human neuronal progenitor cells (derived from embryonic stem cells) and fetal muscle samples by including our novel variants.Our findings advance the knowledge of the genetic architecture of heart rate, and indicate new candidate genes for follow-up functional studies