A penalty approach to the numerical simulation of a constrained wave motion

The main goal of this article is to investigate the numerical solution of a vector-valued nonlinear wave equation, the nonlinearity being of the Ginzburg-Landau type, namely (|u|2-1)u. This equation is obtained when treating by penalty a constrained wave-motion, where the displacement vector is of constant length (1 here, after rescaling). An important step of the approximation process is the construction of a time discretization scheme preserving-in some sense-the energy conservation property of the continuous model. The stability properties of the above scheme are discussed. The authors discuss also the finite element approximation and the quasi-Newton solution of the nonlinear elliptic system obtained at each time step from the time discretization. The results of numerical experiments are presented; they show that for the constraint of the original wave problem to be accurately verified we need to use a small value of the penalty parameter

The feasibility and physiological aspects of anesthesia and surgery without homologous blood transfusion

The modern practice of medicine has an ever-increasing dependency on the blood bank industry. Indeed, on many occasions there is an unwarranted and inappropriate use of hemotherapy. The first recorded blood transfusion was given to Pope Innocent VIII in 1492 (Narengo-Rowe, 1982). three blood donors This treatment was unsuccessful, and the patient and all died as a result of the experiment. Since then physicians have been mesmerized by the "0mnipotent" powers of extraneous blood in reversing disease processes, regardless of the inherent complications or the logical indications for such blood transfusions. It has been estimated that 12 million units of blood are transfused yearly into patients in the United States. This blood comes primarily from volunteer sources, but paid donors must necessarily be used, in order to make up for shortages created by the ever increasing demand. In addition, the cost of whole blood has risen steadily to $100.00 per unit in some hospitals and frozen blood is double this price. On average 2.5 units of blood are used for each transfusion and retrospective data analyses of the need for individual blood transfusions have unifonnly demonstrated that at least half of all blood transfusions were unnecessary. The risks of using homologous blood include isosensitization- disseminated intravascular coagulopathy, febrile reactions, bacterial contamimation, thrombophlebitis, hepatit

Investigation of Lagrange–Galerkin Method for an Obstacle Parabolic Problem

© 2018, Pleiades Publishing, Ltd. The convergence and accuracy estimates are proved for Lagrange–Galerkin method, used for approximating the parabolic obstacle problem. The convergence analysis is based on the comparison of the solutions of Lagrange–Galerkin and backward Euler approximation schemes. First order in time step estimate for the difference of the solutions for above schemes in energy norm is proved under sufficiently weak requirements for the smoothness of the initial data. First order in time and space steps accuracy estimate for Lagrange–Galerkin method is derived in the case of discontinuous time derivative of the exact solution

Finite element approximation and iterative method solution of elliptic control problem with constraints to gradient of state

© 2015, Pleiades Publishing, Ltd. An optimal control problem with distributed control in the right-hand side of Poisson equation is considered. Pointwise constraints on the gradient of state and control are imposed in this problem. The convergence of finite element approximation for this problem is proved. Discrete saddle point problem is constructed and preconditioned Uzawa-type iterative algorithm for its solution is investigated

Clinical and Demographic Predictors of Interdisciplinary Chronic Pain Rehabilitation Program Treatment Response

© 2019 the American Pain Society Patients treated in interdisciplinary chronic pain rehabilitation programs show long-term improvements in symptoms; however, outcomes may vary across heterogenous patient subpopulations. This longitudinal retrospective study characterizes the influence of opioids, mood, patient characteristics, and baseline symptoms on pain and functional impairment (FI) in 1,681 patients 6-months to 12-months post-treatment in an interdisciplinary chronic pain rehabilitation program incorporating opioid weaning. Linear mixed models showed immediate and durable treatment benefits with nonuniform worsening at follow up which slowed over time. Latent class growth analysis identified three post-treatment trajectories of pain and FI: mild symptoms and durable benefits, moderate symptoms and durable benefits, and intractable symptoms. A fourth pain trajectory showed immediate post-treatment improvement and worsening at follow up. Whether a patient was weaned from opioids was not predictive of treatment trajectory. Racial ethnic minority status, higher levels of post-treatment depression, and lower perceived treatment response were associated with less resolution (moderate symptoms) or intractable symptoms. Not having a college education was predictive of intractable or worsening pain and a moderate course of FI. Older age and male gender was associated with intractable FI. Treatment outcomes may be improved by the development of targeted interventions for patients at risk of poor recovery and/or deteriorating long-term course. Perspective: This study examined predictors of treatment response in 1,681 patients treated in an interdisciplinary chronic pain rehabilitation program incorporating opioid weaning. Opioid weaning did not predict outcome. Higher levels of symptoms, lower levels of education, and being a racial-ethnic minority were associated with a less salubrious long-term treatment response

Dynamics of B-Cell Populations in CSF and Blood in Patients Treated with a Combination of Rituximab and Mitoxantrone.

Background. Mitoxantrone (MTX) and Rituximab (RTX) are successfully used for treatment of multiple sclerosis (MS) and can be combined to increase efficacy. Objective. We used MTX, RTX, and methylprednisolone in a single combined regiment and observed patients prospectively. Methods. We present results of observational pilot study of combined therapy of RTX and MTX in 28 patients with active MS. Therapeutic protocol consisted of two infusions within 14 days. First infusion was 1000 mg methylprednisolone (MP) IV, 1000 mg RTX IV, and 20 mg MTX IV. On day 14, 1000 mg MP IV and 1000 mg RTX IV were given. Patients were followed prospectively from 12 to 48 months. Results and Conclusion. There were no relapses among all 28 patients during the observation period. B-cell depletion of CD19+ and CD19+/CD27+ memory B-cell subpopulation in both compartments was confirmed in all patients at 6 months. We found a more rapid reconstitution of B cells in the CSF than in the peripheral blood and longstanding depression of CD19+CD27+ memory B-cell. Conclusion. Effectiveness of combined regimen of RTX and MTX could be related to longstanding depletion of CD19+CD27+ memory B-cell subset

On 3D dynamic control of secondary cooling in continuous casting process

In this paper a 3D-model for simulation and dynamic control of the continuous casting process is presented. The diffusion convection equation with multiphase transition is used as a simulation model. The developed model is discretized by finite element method and the algebraic equations are solved using pointwise relaxation method. Two different type of methods are used to control the secondary cooling, namely PID and optimal control method. The numerical results are presented and analyzed

Fast flowing populations are not well mixed

In evolutionary dynamics, well-mixed populations are almost always associated with all-to-all interactions; mathematical models are based on complete graphs. In most cases, these models do not predict fixation probabilities in groups of individuals mixed by flows. We propose an analytical description in the fast-flow limit. This approach is valid for processes with global and local selection, and accurately predicts the suppression of selection as competition becomes more local. It provides a modelling tool for biological or social systems with individuals in motion.Comment: 19 pages, 8 figure