Generators and relations for wreath products

Generators and defining relations for wreath products of groups are given. Under some condition (conormality of the generators) they are minimal. In particular, it is just the case for the Sylow subgroups of the symmetric groups.Comment: 4 page

Lunar surface dynamics: Some general conclusions and new results from Apollo 16 and 17

Exposure ages of Apollo 17 rocks as measured by tracks and the Kr-Kr rare gas method are reported. Concordant ages of 22 - or + 1 million year (my) are obtained for the station 6 boulder sample 76315. This value is interpreted as the time when the station 6 boulder was emplaced in its present position. Reasonable agreement is also obtained by the two methods for another station 6 boulder, sample 76015. Discordant ages (respectively 5 and 28 my by the track and rare gas methods) are obtained for the station 7 boulder sample, 77135, indicating that the boulder was emplaced at least 5 my ago. The 72 my exposure age of 75035, in general agreement with previous measurements of approximately 85 my for another Camelot boulder, may well date the formation of Camelot. Rock 76015 was split and one surface exposed to the sky through a very small solid angle

MN Draconis - peculiar, active dwarf nova in the period gap

Context: We present results of an extensive world-wide observing campaign of MN Draconis. Aims: MN Draconis is a poorly known active dwarf nova in the period gap and is one of the only two known cases of period gap SU UMa objects showing the negative superhumps. Photometric behaviour of MN Draconis poses a challenge for existing models of the superhump and superoutburst mechanisms. Therefore, thorough investigation of peculiar systems, such as MN Draconis, is crucial for our understanding of evolution of the close binary stars. Methods: To measure fundamental parameters of the system, we collected photometric data in October 2009, June-September 2013 and June-December 2015. Analysis of the light curves, $O-C$ diagrams and power spectra was carried out. Results: During our three observational seasons we detected four superoutburts and several normal outbursts. Based on the two consecutive superoutbursts detected in 2015, the supercycle length was derived P_sc = 74 +/- 0.5 days and it has been increasing with a rate of P_dot = 3.3 x 10^(-3) during last twelve years. Based on the positive and negative superhumps we calculated the period excess epsilon = 5.6% +/- 0.1%, the period deficit epsilon_ = 2.5% +/- 0.6%, and in result, the orbital period P_orb = 0.0994(1) days (143.126 +/- 0.144 min). We updated the basic light curve parameters of MN Draconis. Conclusions: MN Draconis is the first discovered SU UMa system in the period gap with increasing supercycle length.Comment: 14 pages, 20 figures, 8 tables, accepted for publication in Astronomy and Astrophysic

Kinetika rekristalizacije tijekom vrućeg oblikovanja čelika

The theory of kinetics of static recrystallization of steel during hot forming links the phenomenon to certain critical strain, grain size, strain rate, activation energy and temperature. The basic description is provided by the Avrami equation. An overview of equations used was compiled and comments on selected parameters prepared.Teorija kinetike statičke rekristalizacije čelika tijekom vrućeg oblikovanja ovu pojavu povezuje s kritičnom deformacijom, veličinom zrna, brzinom deformacije, aktivacijskom energijom te s temperaturom. Osnovni opis pruža Avrami jednadžba. Rad pruža pregled korištenih jednadžbi i raspravu pojedinih parametara

Kinetika rekristalizacije tijekom vrućeg oblikovanja čelika

The theory of kinetics of static recrystallization of steel during hot forming links the phenomenon to certain critical strain, grain size, strain rate, activation energy and temperature. The basic description is provided by the Avrami equation. An overview of equations used was compiled and comments on selected parameters prepared.Teorija kinetike statičke rekristalizacije čelika tijekom vrućeg oblikovanja ovu pojavu povezuje s kritičnom deformacijom, veličinom zrna, brzinom deformacije, aktivacijskom energijom te s temperaturom. Osnovni opis pruža Avrami jednadžba. Rad pruža pregled korištenih jednadžbi i raspravu pojedinih parametara

Magnetostimulated inhomogeneity of electric field in aluminum

The results of low temperature experimental and theoretical study of potential distribution of stationary electric field in Al under the action of inhomogeneous magnetic field are presented

Bilateral coronary artery to pulmonary trunk fistulae detected by coronary angiography and evaluated by ECG-gated SPECT myocardial perfusion imaging: report of two cases

Coronary artery fistulae (CAF) are anomalies related to coronary artery abnormal termination. This is a very rare congenital malformation accounting for about 0.2–0.4% of congenital cardiac anomalies, but in some patients it can be haemodynamically important. Single-photon emission computed tomography or positron emission tomography myocardial perfusion imaging (MPI) using radioactive agents is widely used in clinical practice for cardiac ischaemia detection as a very sensitive and non-invasive tool. We are going to present 2 patients with bilateral CAFs to the pulmonary trunk without signs of the rest or stress ischaemia in MPI.

Lunar surface engineering properties experiment definition. Volume 3 - Borehole probes Final report, 20 Jun. 1968 - 19 Jul. 1969

Failure mechanisms associated with use of borehole jack in rock

Endoscopic diagnosis and treatment of esophageal diseases

LOCOD, St. Petersburg, Russia, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroduction: Non-neoplastic disorders of the esophagus amount 89-92% of all diseases of the esophagus, these include various esophagitis, diverticula of different localization, stricture of the esophagus and esophageal motility disorders (Mozheiko M.A. et al. 2018). Esophageal neoplasms are divided into benign (5%) and malignant (95%). Aim: Demonstrate the possibilities of endoscopy in the diagnosis and treatment of esophageal disorders. Materials and methods: Modern endoscopic diagnostics includes examination not only in white light, but also light and electronic filters that are used to improve the image and examine the vascular pattern (NBI, ISCAN). If necessary, the study can be supplemented with chromoscopy (Lugol's solution, 1% - acetic acid), which will allow to detailed assessment of the mucosal surface and identify pathological lesions. During the esophagoscopy, it is possible to take material for cytological or histological examination, which is necessary for making a diagnosis. Treatment options for Barrett's esophagus include: argon plasma ablation, resection of foci or radiofrequency ablation. Endoscopic antireflux mucosectomy of the cardiac mucosa is possible at cardiac insufficiency. Benign mucosal neoplasms are possible to remove using loop resection, cap resection of the formation or dissection in the submucosal layer. The first stage with malignant neoplasms is performed EUS to assess the degree of invasion, as well as the presence of regional lymphadenopathy. T1aN0M0 cancer is dissected in the submucosal layer, intraluminal photodynamic therapy is also possible. Neoplasms in the submucosal layer are used submucosal tunneling resection techniques. Achalasia cardia are treated with using dilatation or oral myotomy. Zenker's diverticulum are treated with using diverticuloesophagostomy, and also there is tunneling resection techniques that can be possible. Results: In Oncology Dispensary of Leningrad Regional since 2016 RFA was performed for 27 patients with Barrett's esophagus with dysplasia of various degrees. Endoscopic antireflux mucosectomy of the cardiac mucosa was performed in 4 patients. Conclusions: Endoscopic resection of the esophageal mucosa lesions are performed in 45-50 patients annually. Endoscopic submucosal dissection of esophageal cancer are performed 10-15 patients annually. Submucosal tunneling resection techniques performed 4-5 patients per year

Granular circulation in a cylindrical pan: simulations of reversing radial and tangential flows

Granular flows due to simultaneous vertical and horizontal excitations of a flat-bottomed cylindrical pan are investigated using event-driven molecular dynamics simulations. In agreement with recent experimental results, we observe a transition from a solid-like state, to a fluidized state in which circulatory flow occurs simultaneously in the radial and tangential directions. By going beyond the range of conditions explored experimentally, we find that each of these circulations reverse their direction as a function of the control parameters of the motion. We numerically evaluate the dynamical phase diagram for this system and show, using a simple model, that the solid-fluid transition can be understood in terms of a critical value of the radial acceleration of the pan bottom; and that the circulation reversals are controlled by the phase shift relating the horizontal and vertical components of the vibrations. We also discuss the crucial role played by the geometry of the boundary conditions, and point out a relationship of the circulation observed here and the flows generated in vibratory conveyors.Comment: 10 pages, 8 figure