On critical behaviour in systems of Hamiltonian partial differential equations

We study the critical behaviour of solutions to weakly dispersive Hamiltonian systems considered as perturbations of elliptic and hyperbolic systems of hydrodynamic type with two components. We argue that near the critical point of gradient catastrophe of the dispersionless system, the solutions to a suitable initial value problem for the perturbed equations are approximately described by particular solutions to the Painlev\ue9-I (PI) equation or its fourth-order analogue P2I. As concrete examples, we discuss nonlinear Schr\uf6dinger equations in the semiclassical limit. A numerical study of these cases provides strong evidence in support of the conjecture

Chronic respiratory diseases and risk factors in 12 regions of the Russian Federation

Alexander G Chuchalin,1 Nikolai Khaltaev,2 Nikolay S Antonov,1 Dmitry V Galkin,3 Leonid G Manakov,4 Paola Antonini,5 Michael Murphy,5 Alexander G Solodovnikov,6 Jean Bousquet,7 Marcelo HS Pereira,8 Irina V Demko9 1Institute of Pulmonology, Federal Medical and Biological Agency, Moscow, Russia; 2Global Alliance Against Chronic Respiratory Diseases (GARD), Genève, Switzerland; 3GlaxoSmithKline, Moscow, Russia; 4Far Eastern Scientific Center of Physiology and Pathology of Respiration RAS (Russian Academy of Sciences), Blagoveshchensk, Russia; 5Worldwide Clinical Trials, King of Prussia, PA, USA; 6Worldwide Clinical Trials, Ekaterinburg, Russia; 7Institut National de la Santé et de la Recherche Médicale, Montpellier, France; 8Research and Development Chief Medical Office, International Medical, GlaxoSmithKline, London, United Kingdom; 9Krasnoyarsk State Medical University, Krasnoyarsk, Russia Background: Estimation suggests that at least 4 million people die, annually, as a result of chronic respiratory disease (CRD). The Global Alliance against Chronic Respiratory Diseases (GARD) was formed following a mandate from the World Health Assembly to address this serious and growing health problem. Objectives: To investigate the prevalence of CRD in Russian symptomatic patients and to evaluate the frequency of major risk factors for CRD in Russia. Methods: A cross-sectional, population-based epidemiological study using the GARD questionnaire on adults from 12 regions of the Russian Federation. Common respiratory symptoms and risk factors were recorded. Spirometry was performed in respondents with suspected CRD. Allergic rhinitis (AR) and chronic bronchitis (CB) were defined by the presence of related symptoms according to the Allergic Rhinitis and its Impact on Asthma and the Global Initiative for Obstructive Lung Disease guidelines; asthma was defined based on disease symptoms; chronic obstructive pulmonary disease (COPD) was defined as a post-bronchodilator forced expiratory volume per 1 second/forced vital capacity ratio <0.7 in symptomatic patients, following the Global Initiative for Obstructive Lung Disease guidelines. Results: The number of questionnaires completed was 7,164 (mean age 43.4 years; 57.2% female). The prevalence of asthma symptoms was 25.7%, AR 18.2%, and CB 8.6%. Based on patient self-reported diagnosis, 6.9% had asthma, 6.5% AR, and 22.2% CB. The prevalence of COPD based on spirometry in patients with respiratory symptoms was estimated as 21.8%. Conclusion: The prevalence of respiratory diseases and risk factors was high in Russia when compared to available data. For bronchial asthma and AR, the prevalence for related symptoms was higher than self-reported previous diagnosis. Keywords: chronic respiratory diseases, GARD, Russia, prevalenc