Feller property and infinitesimal generator of the exploration process

We consider the exploration process associated to the continuous random tree (CRT) built using a Levy process with no negative jumps. This process has been studied by Duquesne, Le Gall and Le Jan. This measure-valued Markov process is a useful tool to study CRT as well as super-Brownian motion with general branching mechanism. In this paper we prove this process is Feller, and we compute its infinitesimal generator on exponential functionals and give the corresponding martingale

Homogenization of a stochastic nonlinear reaction-diffusion equation with a large reaction term: the almost periodic framework

Homogenization of a stochastic nonlinear reaction-diffusion equation with a large non- linear term is considered. Under a general Besicovitch almost periodicity assumption on the coefficients of the equation we prove that the sequence of solutions of the said problem converges in probability towards the solution of a rather different type of equation, namely, the stochastic non- linear convection-diffusion equation which we explicitly derive in terms of appropriated functionals. We study some particular cases such as the periodic framework, and many others. This is achieved under a suitable generalized concept of sigma-convergence for stochastic processes.Comment: 34 page

Descent algorithm for nonsmooth stochastic multiobjective optimization

International audienceAn algorithm for solving the expectation formulation of stochastic nonsmooth multiobjective optimization problems is proposed. The proposed method is an extension of the classical stochastic gradient algorithm to multi-objective optimization using the properties of a common descent vector defined 10 in the deterministic context. The mean square and the almost sure convergence of the algorithm are proven. The algorithm efficiency is illustrated and assessed on an academic example

Medical management of neurofibromatosis 1: A cross-sectional study of 383 patients

Background: The morbidity and mortality caused by neurofibromatosis 1 are a result of complications that may involve any of the body systems. Two models of management have been proposed for the detection of various complications in specialized neurofibromatosis clinics: investigation protocols (including extensive imaging and analysis of 24-hour urinary catecholamine levels); or clinical follow-up without imaging. Objective: Our purpose was to validate the strategy of clinical follow-up (without routine imaging and 24-hour urinary catecholamine levels). Methods: We retrospectively compared the number of treated complications during 2 successive periods from our database: screening investigations from November 1988 to June 1995 and clinical examination from July 1995 to June 2000.Results: The number of treated complications during the 2 periods was not statistically different (27/166 vs 28/217; Fisher’s exact test, P = .39). Conclusion: Screening investigations added little to clinical follow-up. Indeed, routine clinical examination can easily identify complications that require treatment in adult patients with neurofibromatosis 1

Performance of the SCORTEN During the First Five Days of Hospitalization to Predict the Prognosis of Epidermal Necrolysis

The SCORTEN, calculated within 24hours of admission, is a severity-of-illness score validated for toxic epidermal necrolysis and Stevens–Johnson syndrome. Our purpose was to assess the performance of successive SCORTEN during the first 5 days of hospitalization and to determine the influence of admission delay. Charts of 144 patients aged 46.8 years (±19.7), admitted to our department (1993–2003) with Stevens–Johnson syndrome or toxic epidermal necrolysis, were reviewed. Successive SCORTEN were compared between deceased patients (n=28, 19.4%) and survivors (n=116). The performance of the score (calibration, discrimination) was assessed on days 1–5. All seven SCORTEN variables, on days 1–5, were associated with a higher mortality rate. The SCORTEN rose slightly during hospitalization, with a significant difference between days 1 and 4 (<0.05). Performance of the SCORTEN was good on each day, but slightly better on day 3. The areas under the receiver-operating characteristic curves were above 80%. The admission delay did not differ between deceased patients and survivors. Delay-adjusted SCORTEN was close to the crude SCORTEN. The SCORTEN performance during the first 5 days of hospitalization was excellent, and at its best on day 3. We recommend to compute again the SCORTEN on day 3. The admission delay did not influence prognosis or SCORTEN

Clinical risk factors for mortality in patients with neurofibromatosis 1: a cohort study of 378 patients

Objective: To identify the main clinical features associated with mortality in patients with neurofibromatosis 1. Design: Cohort study. Setting: Referral center for neurofibromatosis. Patients: Three hundred seventy-eight patients with neurofibromatosis 1 who had more than 1 year of follow-up in the center. Main Outcome Measures: Mortality. Clinical features, especially dermatological, were evaluated as potential factors associated with mortality. Results: Factors associated independently with mortality were the presence of subcutaneous neurofibromas (odds ratio, 10.8; 95% confidence interval, 2.1-56.7;

Sneddon syndrome revealing dysfibrinogenemia

Sneddon syndrome (SS) is the association of cerebral ischemic events and livedo and is caused by vascular thrombosis. It is often associated with a primitive antiphospholipid syndrome (PAPS). In other cases, several thrombophilic conditions have been implicated. Dysfibrinogenemia is a qualitative defect of fibrinogen. Some families with dysfibrinogenemia have been reported to present thrombotic events. We describe here the first reported case of SS with dysfibrinogenemia