4,983 research outputs found

    Track parameter propagation through the application of a new adaptive Runge-Kutta-Nystrom method in the ATLAS experiment

    Get PDF
    In this paper we study several fixed step and adaptive Runge-Kutta methods suitable for transporting track parameters through an inhomogeneous magnetic field. Moreover, we present a new adaptive Runge-Kutta-Nystrom method which estimates the local error of the extrapolation without introducing extra stages to the original Runge-Kutta-Nystrom method. Furthermore, these methods are compared for propagation accuracy and computing cost efficiency in the simultaneous track and error propagation (STEP) algorithm of the common ATLAS tracking software. The tests show the new adaptive Runge-Kutta-Nystrom method to be the most computing cost efficient

    Transport of covariance matrices in the inhomogeneous magnetic field of the ATLAS experiment by the application of a semi-analytical method

    Get PDF
    In this paper we study the transport of track parameter covariance matrices - the so-called error propagation - in the inhomogeneous magnetic field of the ATLAS experiment. The Jacobian elements are transported in parallel with the track parameters, avoiding the inherent need of any purely numerical scheme of propagating a set of auxiliary tracks. We evaluate the quality of the transported Jacobians by a very thorough, purely numerical approach of obtaining the same derivatives, providing a quantitative understanding of the effects of including gradients of energy loss and the magnetic field on the accuracy of the error propagation. Irrespective of the accuracy of the underlying track parameter propagation, the method of parallel integration of the derivatives is demonstrated to be significantly faster than even the simplest numerical scheme. The error propagation presented in this paper is part of the simultaneous track and error propagation (STEP) algorithm of the common ATLAS tracking software

    Passenger mutations and aberrant gene expression in congenic tissue plasminogen activator‐deficient mouse strains

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134273/1/jth13338_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134273/2/jth13338.pd

    Predicting NOx emissions from wood stoves using detailed chemistry and computational fluid dynamics

    Get PDF
    -The present paper addresses NOx emissions from wood stoves through a computational fluid dynamics (CFD) modeling approach. The most significant route for NOx formation in traditional biomass combustion applications is the fuel NOx mechanism. The formation of fuel NOx is very complex and sensitive to fuel composition and combustion conditions. Thus, accurate predictions of fuel NOx formation in wood stoves, which constitute a wide range of compositions and states, rely heavily on the use of chemical kinetics with sufficient level of details. In the present work we use CFD together with three gas phase reaction mechanisms; one detailed mechanism consisting of 81 species and 1401 reactions, and two skeletal mechanisms with 49 and 36 species respectively to predict NOx emissions from wood stoves. The results show that; using the detailed mechanism as reference the 49-specie reaction mechanism predict similar results whilst the 36-specie mechanism overpredicts the total amount of fixed nitrogen emissions (NO, NO2, N2O, HCN, NH3) whilst underpredicting NOx emissions. Furthermore, the results indicate that even in these small-scale applications, air staging can be used to reduce the NOx emissions

    Factors affecting continuation of clean intermittent catheterisation in people with multiple sclerosis: results of the COSMOS mixed-methods study

    Get PDF
    Background:  Clean intermittent catheterisation (CIC) is often recommended for people with multiple sclerosis (MS).  Objective:  To determine the variables that affect continuation or discontinuation of the use of CIC.  Methods:  A three-part mixed-method study (prospective longitudinal cohort (n = 56), longitudinal qualitative interviews (n = 20) and retrospective survey (n = 456)) was undertaken, which identified the variables that influenced CIC continuation/discontinuation. The potential explanatory variables investigated in each study were the individual’s age, gender, social circumstances, number of urinary tract infections, bladder symptoms, presence of co-morbidity, stage of multiple sclerosis and years since diagnosis, as well as CIC teaching method and intensity.  Results:  For some people with MS the prospect of undertaking CIC is difficult and may take a period of time to accept before beginning the process of using CIC. Ongoing support from clinicians, support at home and a perceived improvement in symptoms such as nocturia were positive predictors of continuation. In many cases, the development of a urinary tract infection during the early stages of CIC use had a significant detrimental impact on continuation.  Conclusion:  Procedures for reducing the incidence of urinary tract infection during the learning period (i.e. when being taught and becoming competent) should be considered, as well as the development of a tool to aid identification of a person’s readiness to try CIC

    Treatment of energy loss and multiple scattering in the context of track parameter and covariance matrix propagation in continuous material in the ATLAS experiment

    Get PDF
    In this paper we study the energy loss, its fluctuations, and the multiple scattering of particles passing through matter, with an emphasis on muons. In addition to the well-known Bethe-Bloch and Bethe-Heitler equations describing the mean energy loss from ionization and bremsstrahlung respectively, new parameterizations of the mean energy loss of muons from the direct e+e- pair production and photonuclear interactions are presented along with new estimates of the most probable energy loss and its fluctuations in the ATLAS calorimeters. Moreover, a new adaptive Highland/Moliere approach to finding the multiple scattering angle is taken to accomodate a wide range of scatterer thicknesses. Furthermore, tests of the muon energy loss, its fluctuations, and multiple scattering are done in the ATLAS calorimeters. The material effects described in this paper are all part of the simultaneous track and error propagation (STEP) algorithm of the common ATLAS tracking software

    Precision determination of band offsets in strained InGaAs/GaAs quantum wells by C-V-profiling and Schroedinger-Poisson self-consistent simulation

    Full text link
    The results of measurements and numerical simulation of charge carrier distribution and energy states in strained quantum wells In_xGa_{1-x}As/GaAs (0.06 < x < 0.29) by C-V-profiling are presented. Precise values of conduction band offsets for these pseudomorphic QWs have been obtained by means of self-consistent solution of Schroedinger and Poisson equations and following fitting to experimental data. For the conduction band offsets in strained In_xGa_{1-x}As/GaAs - QWs the expression DE_C(x) = 0.814x - 0.21x^2 has been obtained.Comment: 9 pages, 12 figures, RevTeX

    Effectiveness and cost-effectiveness of biofeedback-assisted pelvic floor muscle training for female urinary incontinence: a multicentre randomised controlled trial

    Get PDF
    This is the author accepted manuscript. The final version is available from Wiley via the DOI in this recordICS 2019: International Continence Society 49th Annual Meeting, 3-6 September 2019, Gothenburg, SwedenNational Institute for Health Research (NIHR
    corecore