679 research outputs found

    Modelling and simulation framework for reactive transport of organic contaminants in bed-sediments using a pure java object - oriented paradigm

    Get PDF
    Numerical modelling and simulation of organic contaminant reactive transport in the environment is being increasingly relied upon for a wide range of tasks associated with risk-based decision-making, such as prediction of contaminant profiles, optimisation of remediation methods, and monitoring of changes resulting from an implemented remediation scheme. The lack of integration of multiple mechanistic models to a single modelling framework, however, has prevented the field of reactive transport modelling in bed-sediments from developing a cohesive understanding of contaminant fate and behaviour in the aquatic sediment environment. This paper will investigate the problems involved in the model integration process, discuss modelling and software development approaches, and present preliminary results from use of CORETRANS, a predictive modelling framework that simulates 1-dimensional organic contaminant reaction and transport in bed-sediments

    Electrode positions, transformation coordinates for ECG reconstruction from S-ICD vectors.

    Get PDF
    The article contains data pertaining to the reconstruction of an 8-lead ECG from 2 subcutaneous implantable cardioverter defibrillator vectors. The location of electrodes on the precordium required for the data collection are detailed; the flow chart for patient selection and exclusion is shown; the summary data of the root mean square error (RMSE) (in microvolts) and Pearson r for the ECG transformation all cases and the pearson correlation for all the leads measured and reconstructed leads are also shown. Detailed background, methodology and discussion can be found in the linked research article

    Timing of cardiac resynchronization therapy implantation

    Get PDF
    Aims The optimum timing of cardiac resynchronization therapy (CRT) implantation is unknown. We explored long-term outcomes after CRT in relation to the time interval from a first heart failure hospitalization (HFH) to device implantation. .Methods A database covering the population of England (56.3 million in 2019) was used to quantify clinical outcomes after CRT im- and results plantation in relation to first HFHs. From 2010 to 2019, 64 968 patients [age: 71.4 ± 11.7 years; 48 606 (74.8%) male] underwent CRT implantation, 57% in the absence of a previous HFH, 12.9% during the first HFH, and 30.1% after ≥1 HFH. Over 4.54 (2.80–6.71) years [median (interquartile range); 272 989 person-years], the time in years from the first HFH to CRT implantation was associated with a higher risk of total mortality [hazard ratio (HR); 95% confidence intervals (95% CI)] (1.15; 95% CI 1.14–1.16, HFH (HR: 1.26; 95% CI 1.24–1.28), and the combined endpoint of total mortality or HFH (HR: 1.19; 95% CI 1.27–1.20) than CRT in patients with no previous HFHs, after co-variate adjustment. Total mortality (HR: 1.67), HFH (HR: 2.63), and total mortality or HFH (HR: 1.92) (all P < 0.001) were highest in patients undergoing CRT ≥2 years after the first HFH. Conclusion In this study of a healthcare system covering an entire nation, delays from a first HFH to CRT implantation were associated with progressively worse long-term clinical outcomes. The best clinical outcomes were observed in patients with no previous HFH and in those undergoing CRT implantation during the first HFH. Condensed The optimum timing of CRT implantation is unknown. In this study of 64 968 consecutive patients, delays from a first heart abstract failure hospitalization (HFH) to CRT implantation were associated with progressively worse long-term clinical outcomes. Each year from a first HFH to CRT implantation was associated with a 21% higher risk of total mortality and a 34% higher risk of HFH. The best outcomes after CRT were observed in patients with no previous HFHs and in those undergoing implantation during their first HFH. The left upper panel shows the timing (y-axis) and numbers (x-axis) of cardiac resynchronization therapy (CRT) implantations in relation to the timing of first heart failure hospitalizations (HFHs); the right upper panel shows CRT implantations undertaken during a first HFH as a percentage of all implantations, according to year. Patients were regarded as not having had a HFH if this had not occurred within 5 years prior to CRT implantation. The left lower panel shows the Kaplan–Meier survival curve for total mortality. Event rates (per 100 person-years) for the three endpoints according to the timing of CRT implantation in relation to a first HFH are shown in the right lower panel

    Symmetry-breaking transitions in networks of nonlinear circuit elements

    Full text link
    We investigate a nonlinear circuit consisting of N tunnel diodes in series, which shows close similarities to a semiconductor superlattice or to a neural network. Each tunnel diode is modeled by a three-variable FitzHugh-Nagumo-like system. The tunnel diodes are coupled globally through a load resistor. We find complex bifurcation scenarios with symmetry-breaking transitions that generate multiple fixed points off the synchronization manifold. We show that multiply degenerate zero-eigenvalue bifurcations occur, which lead to multistable current branches, and that these bifurcations are also degenerate with a Hopf bifurcation. These predicted scenarios of multiple branches and degenerate bifurcations are also found experimentally.Comment: 32 pages, 11 figures, 7 movies available as ancillary file

    Construction innovation: theory & practice

    Get PDF
    The challenges of reducing global output of greenhouse gases and the need for resource efficiency require a step-change in the way we construct buildings. However, the construction industry has a reputation for being conservative and slow to change. This lecture will present a case study of innovation and describe an emergent framework for describing innovation in construction

    Quantification of Spatial Parameters in 3D Cellular Constructs Using Graph Theory

    Get PDF
    Multispectral three-dimensional (3D) imaging provides spatial information for biological structures that cannot be measured by traditional methods. This work presents a method of tracking 3D biological structures to quantify changes over time using graph theory. Cell-graphs were generated based on the pairwise distances, in 3D-Euclidean space, between nuclei during collagen I gel compaction. From these graphs quantitative features are extracted that measure both the global topography and the frequently occurring local structures of the “tissue constructs.” The feature trends can be controlled by manipulating compaction through cell density and are significant when compared to random graphs. This work presents a novel methodology to track a simple 3D biological event and quantitatively analyze the underlying structural change. Further application of this method will allow for the study of complex biological problems that require the quantification of temporal-spatial information in 3D and establish a new paradigm in understanding structure-function relationships
    corecore