Conservation laws, exact travelling waves and modulation instability for an extended nonlinear Schr\"odinger equation

We study various properties of solutions of an extended nonlinear Schr\"{o}dinger (ENLS) equation, which arises in the context of geometric evolution problems -- including vortex filament dynamics -- and governs propagation of short pulses in optical fibers and nonlinear metamaterials. For the periodic initial-boundary value problem, we derive conservation laws satisfied by local in time, weak $H^2$ (distributional) solutions, and establish global existence of such weak solutions. The derivation is obtained by a regularization scheme under a balance condition on the coefficients of the linear and nonlinear terms -- namely, the Hirota limit of the considered ENLS model. Next, we investigate conditions for the existence of traveling wave solutions, focusing on the case of bright and dark solitons. The balance condition on the coefficients is found to be essential for the existence of exact analytical soliton solutions; furthermore, we obtain conditions which define parameter regimes for the existence of traveling solitons for various linear dispersion strengths. Finally, we study the modulational instability of plane waves of the ENLS equation, and identify important differences between the ENLS case and the corresponding NLS counterpart. The analytical results are corroborated by numerical simulations, which reveal notable differences between the bright and the dark soliton propagation dynamics, and are in excellent agreement with the analytical predictions of the modulation instability analysis.Comment: 27 pages, 5 figures. To be published in Journal of Physics A: Mathematical and Theoretica

On the Acceptable Risk for Structures Subjected to Geohazards

Geohazards such as earthquakes or landslides represent a major risk to structures. In this contribution risk acceptance criteria for structures subjected to geohazards are reviewed. Especially the implementation of human safety and cost benefit considerations are discussed. Current trends in the definition of target safety criteria for structures subjected to earthquakes and landslides are presented and conclusions regarding codified criteria are drawn

Perils and Pitfalls Regarding Differential Diagnosis and Treatment of Primary Cutaneous Anaplastic Large-Cell Lymphoma

Primary cutaneous anaplastic large-cell lymphoma (PC-ALCL), belonging to the CD30+ T-cell lymphoproliferative disorders (PCLPDs), is a rare T-cell lymphoma, presenting on the skin and characterized by very good prognosis and response to treatment in the majority of cases. Nevertheless, PC-ALCL must be distinguished from secondary skin lesions in systemic ALCL, which confer a poor prognosis, and other CD30+ PCLPDs, reactive conditions, or borderline cases. Given their rarity and heterogeneity, these entities represent diagnostic and therapeutic challenges, thus requiring a multidisciplinary approach and expertise to ensure appropriate diagnosis and management. There are several perils and pitfalls that exist regarding the differential diagnosis, the possible progression, and the treatment of PC-ALCL. Careful staging, correlation of clinical findings with histopathology and immunopathology, and thorough follow-up are essential in order to achieve a correct diagnosis and proper treatment of the disease

Long-term exposure to ambient air pollution and renal function in African Americans: the Jackson Heart Study

Renal dysfunction is prevalent in the US among African Americans. Air pollution is associated with renal dysfunction in mostly white American populations, but has not been studied among African Americans. We evaluated cross-sectional associations between 1-year and 3-year fine particulate matter (PM2.5) and ozone (O3) concentrations, and renal function among 5090 African American participants in the Jackson Heart Study. We used mixed-effect linear regression to estimate associations between 1-year and 3-year PM2.5 and O3 and estimated glomerular filtration rate (eGFR), urine albumin/creatinine ratio (UACR), serum creatinine, and serum cystatin C, adjusting for: sociodemographic factors, health behaviors, and medical history and accounting for clustering by census tract. At baseline, JHS participants had mean age 55.4 years, and 63.8% were female; mean 1-year and 3-year PM2.5 concentrations were 12.2 and 12.4 µg/m3, and mean 1-year and 3-year O3 concentrations were 40.2 and 40.7 ppb, respectively. Approximately 6.5% of participants had reduced eGFR ( 30 mg/g), both indicating impaired renal function. Annual and 3-year O3 concentrations were inversely associated with eGFR and positively associated with serum creatinine; annual and 3-year PM2.5 concentrations were inversely associated with UACR. We observed impaired renal function associated with increased O3 but not PM2.5 exposure among African Americans

Corynebacterium jeikeium bacteremia in a hemodialyzed patient

SummaryCorynebacterium jeikeium, frequently encountered in clinical specimens, is part of the normal skin flora. Nevertheless, a few cases of C. jeikeium bacteremia followed by severe clinical manifestations have been reported. C. jeikeium has been reported to cause endocarditis, septicemia, meningitis, pneumonia and osteomyelitis, along with soft tissue and trauma infections. Herein we describe a case of C. jeikeium bacteremia in Greece. The isolation of a coryneform bacterium from a clinical specimen should not immediately be considered a superinfection by the skin flora. Clinical and laboratory investigations are essential in order to evaluate such cases before applying appropriate treatment. On the other hand, the association of coryneform bacteria and disease should be critically investigated, with a thorough identification of the strain, ideally beyond the classical methods, at a specialized center

Nonlinear analysis of magnetospheric data Part II. Dynamical characteristics of the AE index time series and comparison with nonlinear surrogate data

International audienceIn this study we have used dynamical characteristies such as Lyapunov exponents, nonlinear dynamic models and mutual information for the nonlinear analysis of the magnetospheric AE index time series. Similarly with the geometrical characteristic studied in Pavlos et al. (1999b), we have found significant differences between the original time series and its surrogate data. These results also suggest the rejection of the null hypothesis that the AE index belongs to the family of stochastic linear signals undergoing a static nonlinear distortion. Finally, we believe that these results support the hypothesis of nonlinearity and chaos for the magnetospheric dynamics

Comments and new results about the magnetospheric chaos hypothesis

International audienceIn this study we present theoretical concepts and results concerning the hypothesis test of the magnetospheric chaos. For this reason we compare the observational behavior of the magnetospheric system with results obtained by analysing different types of stochastic and deterministic input-output systems. The results of this comparison indicate that the hypothesis of lowdimensional chaos for the magnetospheric dynamics remains a possible and fruitful concept which must be developed further