Asymptotic models for the generation of internal waves by a moving ship, and the dead-water phenomenon

This paper deals with the dead-water phenomenon, which occurs when a ship sails in a stratified fluid, and experiences an important drag due to waves below the surface. More generally, we study the generation of internal waves by a disturbance moving at constant speed on top of two layers of fluids of different densities. Starting from the full Euler equations, we present several nonlinear asymptotic models, in the long wave regime. These models are rigorously justified by consistency or convergence results. A careful theoretical and numerical analysis is then provided, in order to predict the behavior of the flow and in which situations the dead-water effect appears.Comment: To appear in Nonlinearit

Quality of life of adults with cerebral palsy living in britanny

IntroductionJust a few studies have been published about health related quality of life of adults with cerebral palsy and no at our knowledge in the French population. The objective of this study is to obtain an image of health related quality of life of BreizhPC network users.MethodsA questionnaire was sent to all network users. This questionnaire concerned the people living: work, leisure, clinical complaints, as well as a self SF36 quality of life questionnaire. The SF-36 quality of life give information in different fields: physical activity, emotional life, vitality, general health. The questionnaires were analyzed according to the disability, the influence of social status, level of disability and major clinical disorders. The statistical analysis used the Student test.ResultsEight-hundred questionnaires were sent out, 173 users responded, 81 women and 92 men, with a mean age of 42. That represents 22% of the contacted population. The data from 115 people have been exploited. The average age of the population is 42 years. The level of motor disability, travel difficulties, sleep disorders, pain, urinary and transit disorders negatively influence the quality of life. On the other side, sex, employment, epilepsy, communication and swallowing disorders, active sexuality had no influence.Discussion/conclusionOur results are closed to the literature with some variations, they emphasize the decrease in quality of life in adults with cerebral palsy. Some factors appear more important and require definitely more attention to improve the quality of life experienced by patients: travel difficulties, pain, urinary and transit disorders and sleep disorders