Nonlinear acoustic waves in channels with variable cross sections

The point symmetry group is studied for the generalized Webster-type equation describing non-linear acoustic waves in lossy channels with variable cross sections. It is shown that, for certain types of cross section profiles, the admitted symmetry group is extended and the invariant solutions corresponding to these profiles are obtained. Approximate analytic solutions to the generalized Webster equation are derived for channels with smoothly varying cross sections and arbitrary initial conditions.Comment: Revtex4, 10 pages, 2 figure. This is an enlarged contribution to Acoustical Physics, 2012, v.58, No.3, p.269-276 with modest stylistic corrections introduced mainly in the Introduction and References. Several typos were also correcte

Characteristics of a 1-year outpatient management of patients after myocardial infarction: data from a Russian multicenter study

Aim. To evaluate a 1-year outpatient management of patients after myocardial infarction (MI) aged <75 years according to a Russian multicenter study, as well as to assess compliance with recommendations on the frequency of visiting specialists and the performance of diagnostic examinations.Material and methods. This observational study includes a representative sample of MI patients admitted to 16 clinics in 13 Russian regions. Patients with MI who were alive the next day after hospitalization aged <75 years were included in the study according to a special randomization scheme. When writing this article, the data from questionnaires of 6 and 12 months after hospitalization were analyzed: the number of visits to doctors of various specialties, hospitalizations, the number of diagnostic procedures performed (electrocardiography (ECG), echocardiography and surgical interventions (percutaneous coronary intervention, coronary artery bypass grafting (CABG)). The study included a cohort of 723 patients who participated in the survey both 6 and 12 months after hospitalization (67% — patients discharged from the hospital), of which 562 (77,7%) were men and 161 (22,3%) — women. Statistical processing was performed using IBM SPSS Statistics v.25 software for Windows.Results. In the first 6 months after MI, 218 (38,8%) men and 62 (38,5%) women visited the cardiologist the recommended number of times. However, 151 (20,9%) people were not monitored by a cardiologist in the first six months. There was a significant increase in the number of people not observed during the second 6 months up to 209 (28,9%) people (p<0,01). Of the 689 interviewed patients, 210 (30,5%) people visited the therapist the recommended number of times in the first six months, while in the second 6 months — 402 (58,4%) patients. It is also reasonable to single out patients who were not monitored by either a cardiologist or a general practitioner into a separate group. In the first 6 months, the total number of unobserved patients was 68 (7,5%), while in the second six months this number increased to 189 (25,9%). The recommended number of ECGs (4 or more times) was performed in 316 (40,4%) patients, while ECG was not performed in 35 (4,5%) patients. Echocardiography 2 or more times was performed in 194 (25,4%) patients. The procedure was not performed in 167 (21,9%) patients. During the first 6 months, 170 (22%) people were hospitalized, while 156 (20,2%) — during the second half of the year. Angioplasty during the first 12 months after discharge from the hospital was performed in 183 (23,1%) patients, CABG — in 41 (5,2%) patients without age and sex differences.Conclusion. Outpatient management of patients aged <75 years 12 months after MI characterized by low compliance with recommendations on the number of cardiologist consultations and diagnostic procedures, which may adversely affect adherence to the recommended drug treatment and lead to a worse prognosis

Baikal-GVD: status and prospects

Baikal-GVD is a next generation, kilometer-scale neutrino telescope under construction in Lake Baikal. It is designed to detect astrophysical neutrino fluxes at energies from a few TeV up to 100 PeV. GVD is formed by multi-megaton subarrays (clusters). The array construction started in 2015 by deployment of a reduced-size demonstration cluster named "Dubna". The first cluster in its baseline configuration was deployed in 2016, the second in 2017 and the third in 2018. The full scale GVD will be an array of ~10000 light sensors with an instrumented volume of about 2 cubic km. The first phase (GVD-1) is planned to be completed by 2020-2021. It will comprise 8 clusters with 2304 light sensors in total. We describe the design of Baikal-GVD and present selected results obtained in 2015-2017.Comment: 9 pages, 8 figures. Conference proceedings for QUARKS201