72 research outputs found

    Optimization of charging strategies for electric vehicles in PowerMatcher-driven smart energy grids

    Get PDF
    A crucial challenge in future smart energy grids is the large-scale coordination of distributed energy demand and generation. The well-known PowerMatcher is a promising approach that integrates demand and supply exibility in the operation of the electricity system through dynamic pricing and a hierarchical bidding coordination scheme. However, as the PowerMatcher focuses on short-term coordination of demand and supply, it cannot fully exploit the exibility of e.g. electric vehicles over longer periods of time. In this paper, we propose an extension of the PowerMatcher comprising a planning module, which provides coordinated predictions of demand/price over longer times as input to the users for determining their short-term bids. The optimal short-term bidding strategy minimizing a user's costs is then formulated as a Stochastic Dynamic Programming (SDP) problem. We derive an analytic solution for this SDP problem leading to a simple short-term bidding strategy. Numerical results using real-world data show a substantial performance improvement compared to the standard PowerMatcher, without significant additional complexity

    Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

    Get PDF
    The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∼8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD

    The effect of cataract on early stage glaucoma detection using spatial and temporal contrast sensitivity tests

    Get PDF
    Background: To investigate the effect of cataract on the ability of spatial and temporal contrast sensitivity tests used to detect early glaucoma. Methods: Twenty-seven glaucoma subjects with early cataract (mean age 60 ±10.2 years) which constituted the test group were recruited together with twenty-seven controls (cataract only) matched for age and cataract type from a primary eye care setting. Contrast sensitivity to flickering gratings at 20 Hz and stationary gratings with and without glare, were measured for 0.5, 1.5 and 3 cycles per degree (cpd) in central vision. Perimetry and structural measurements with the Heidelberg Retinal Tomograph (HRT) were also performed. Results: After considering the effect of cataract, contrast sensitivity to stationary gratings was reduced in the test group compared with controls with a statistically significant mean difference of 0.2 log units independent of spatial frequency. The flicker test showed a significant difference between test and control group at 1.5 and 3 cpd (p = 0.019 and p = 0.011 respectively). The percentage of glaucoma patients who could not see the temporal modulation was much higher compared with their cataract only counterparts. A significant correlation was found between the reduction of contrast sensitivity caused by glare and the Glaucoma Probability Score (GPS) as measured with the HRT (p<0.005). Conclusions: These findings indicate that both spatial and temporal contrast sensitivity tests are suitable for distinguishing between vision loss as a consequence of glaucoma and vision loss caused by cataract only. The correlation between glare factor and GPS suggests that there may be an increase in intraocular stray light in glaucoma

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

    No full text
    Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

    Studies on yield losses caused by the stem borers Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) and Busseola fusca (Fuller) (Lepidoptera: Noctuidae) in grain sorghum

    No full text
    Thesis (M. Sc. Agric.) -- University of Stellenbosch, 1989.Full text to be digitised and attached to bibliographic record

    The effect of the adjuvant, Break-Thru S240, on whorl penetration and efficacy of foliar insecticide applications against Chilo partellus

    No full text
    Insecticide sprays registered for the control of maize stem borers are all intended for whorl application. Chemical control of these pests is complicated by their cryptic feeding habit inside plant whorls. The aim of this study was to investigate whether addition of the organosilicone adjuvant, Break-Thru S240, to insecticide sprays would result in improved stem borer control. In one experiment the position of stem borer feeding damage inside plant whorls was quantified to have a standard for comparison and evaluation of the effective distances of downwards movement of spray applications into whorls. The distance of movement of spray applications at five adjuvant rates (50, 100, 200, 400 & 600 ml ha-1) into whorl leaves was determined. A colorant was added to spray applications to facilitate measuring the distances of downwards movement of water into each whorl leaf. A 14% increase in downwards movement of sprays into the target zone was observed with addition of the adjuvant. Efficacy of insecticide sprays for control of C. partellus with and without the adjuvant was evaluated under field conditions. Increased levels of efficacy were observed with addition of the adjuvant but not with all the insecticideshttp://search.sabinet.co.za/WebZ/Authorize?sessionid=0&next=ej/ej_content_plantsoil.html&bad=error/authofail.htm
    corecore