2,506 research outputs found

    Streamwise forced oscillations of circular and square cylinders

    Get PDF
    The modification of a cylinder wake by streamwise oscillation of the cylinder at the vortex shedding frequency of the unperturbed cylinder is reported. Recent numerical simulations [J. S. Leontini, D. Lo Jacono, and M. C. Thompson, “A numerical study of an inline oscillating cylinder in a free stream,” J. Fluid Mech. 688, 551–568 (2011)] showed that this forcing results in the primary frequency decreasing proportionally to the square of the forcing amplitude, before locking to a subharmonic at higher amplitudes. The experimental results presented here show that this behavior continues at higher Reynolds numbers, although the flow is three-dimensional. In addition, it is shown that this behavior persists when the body is a square cross section, and when the frequency of forcing is detuned from the unperturbed cylinder shedding frequency. The similarity of the results across Reynolds number, geometry, and frequency suggests that the physical mechanism is applicable to periodic forcing of the classic von Ka ́rma ́n vortex street, regardless of the details of the body which forms the street

    ANI-1, A data set of 20 million calculated off-equilibrium conformations for organic molecules

    Get PDF
    One of the grand challenges in modern theoretical chemistry is designing and implementing approximations that expedite ab initio methods without loss of accuracy. Machine learning (ML) methods are emerging as a powerful approach to constructing various forms of transferable atomistic potentials. They have been successfully applied in a variety of applications in chemistry, biology, catalysis, and solid-state physics. However, these models are heavily dependent on the quality and quantity of data used in their fitting. Fitting highly flexible ML potentials, such as neural networks, comes at a cost: a vast amount of reference data is required to properly train these models. We address this need by providing access to a large computational DFT database, which consists of more than 20 M off equilibrium conformations for 57,462 small organic molecules. We believe it will become a new standard benchmark for comparison of current and future methods in the ML potential community

    Comparison of best versus worst clinical outcomes for adult cervical deformity surgery

    Get PDF
    Study Design: Retrospective cohort study. Objective: Factors that predict outcomes for adult cervical spine deformity (ACSD) have not been well defined. To compare ACSD patients with best versus worst outcomes. Methods: This study was based on a prospective, multicenter observational ACSD cohort. Best versus worst outcomes were compared based on Neck Disability Index (NDI), Neck Pain Numeric Rating Scale (NP-NRS), and modified Japanese Orthopaedic Association (mJOA) scores. Results: Of 111 patients, 80 (72%) had minimum 1-year follow-up. For NDI, compared with best outcome patients (n = 28), worst outcome patients (n = 32) were more likely to have had a major complication ( Conclusions: Factors distinguishing best and worst ACSD surgery outcomes included patient, surgical, and radiographic factors. These findings suggest areas that may warrant greater awareness to optimize patient counseling and outcomes

    Quality and patient safety in the diagnosis of breast cancer

    Get PDF
    AbstractThe media, medical legal, and safety science perspectives of a laboratory medical error differ and assign variable levels of responsibility on individuals and systems. We examine how the media identifies, communicates, and interprets information related to anatomic pathology breast diagnostic errors compared to groups using a safety science Lean-based quality improvement perspective. The media approach focuses on the outcome of error from the patient perspective and some errors have catastrophic consequences. The medical safety science perspective does not ignore the importance of patient outcome, but focuses on causes including the active events and latent factors that contribute to the error. Lean improvement methods deconstruct work into individual steps consisting of tasks, communications, and flow in order to understand the affect of system design on current state levels of quality. In the Lean model, system redesign to reduce errors depends on front-line staff knowledge and engagement to change the components of active work to develop best practices. In addition, Lean improvement methods require organizational and environmental alignment with the front-line change in order to improve the latent conditions affecting components such as regulation, education, and safety culture. Although we examine instances of laboratory error for a specific test in surgical pathology, the same model of change applies to all areas of the laboratory
    corecore