On random flights with non-uniformly distributed directions

This paper deals with a new class of random flights $\underline{\bf X}_d(t),t>0,$ defined in the real space $\mathbb{R}^d, d\geq 2,$ characterized by non-uniform probability distributions on the multidimensional sphere. These random motions differ from similar models appeared in literature which take directions according to the uniform law. The family of angular probability distributions introduced in this paper depends on a parameter $\nu\geq 0$ which gives the level of drift of the motion. Furthermore, we assume that the number of changes of direction performed by the random flight is fixed. The time lengths between two consecutive changes of orientation have joint probability distribution given by a Dirichlet density function. The analysis of $\underline{\bf X}_d(t),t>0,$ is not an easy task, because it involves the calculation of integrals which are not always solvable. Therefore, we analyze the random flight $\underline{\bf X}_m^d(t),t>0,$ obtained as projection onto the lower spaces $\mathbb{R}^m,m<d,$ of the original random motion in $\mathbb{R}^d$. Then we get the probability distribution of $\underline{\bf X}_m^d(t),t>0.$ Although, in its general framework, the analysis of $\underline{\bf X}_d(t),t>0,$ is very complicated, for some values of $\nu$, we can provide some results on the process. Indeed, for $\nu=1$, we obtain the characteristic function of the random flight moving in $\mathbb{R}^d$. Furthermore, by inverting the characteristic function, we are able to give the analytic form (up to some constants) of the probability distribution of $\underline{\bf X}_d(t),t>0.$Comment: 28 pages, 3 figure

Application of Molecular Typing Methods for Analysis of Strains of Rickettsiae of the Spotted Fever Group and Rabies Virus

50 strains of spotted fever group (SFG) rickettsiae and 36 lyssaviruses strains from the collection of Omsk Research Institute of Natural Focus Infections were identified and typed using the approaches of molecular biology, epidemiology and bioinformatics. The taxonomic status of the studied cultures of SFG rickettsiae was identified. Zonation of the Russian Federation territories according to the spread of SFG pathogenic rickettsiae in their hosts - ixodic ticks was carried out. Lyssaviruses distribution in the territory of Siberia was considered

Интенсивная терапия при муковисцидозе взрослых

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Radionuclide Diagnosis of Esophageal Dysmotility and Gastroesophageal Reflux in Patients with Systemic Sclerosis

Objective: to evaluate the possibilities of dynamic scintigraphy for the diagnosis of esophageal dysmotility (ED) and gastroesophageal reflux (GER) in patients with systemic sclerosis (SS).Material and methods. The study group included 77 patients with established SS of different disease duration (from several months to 30 years) who underwent Technephyt 99mTc dynamic esophageal scintigraphy using two-stage protocol. During the first stage, the esophageal transport function was evaluated; during the second stage, the presence and severity of GER were assessed. Scans were analyzed using visual assessment, quantitative estimation of time/activity curves, and a proposed three-point scale for evaluating ED and GER severity. The control group consisted of 19 practically healthy individuals who underwent a routine examination to exclude digestive system and gastrointestinal tract diseases, the algorithm of which included dynamic scintigraphy.Results. ED was found in 74 of 77 patients (96%). According to three-point scale, severe ED (3 points) was registrated in 41 (55%) patients, moderate ED (2 points) in 15 (21%), and mild ED in 18 (24%). GER was diagnosed in 35 of 77 cases (45%): mild GER in 13 (37%), moderate GER (2 points) in 22 (63%), and none of the patients was found to have severe GER (3 points). A significant relationship between the presence of GER and the severity of ED was not obtained, but a direct correlation was established between ED and GER severity.Conclusion. Most SS patients demonstrated ED of varying severity associated with mild and moderate GER in nearly 45% of the cases. The study results confirm the practical significance of dynamic scintigraphy for assessing the esophageal transport function and GER in SS patients

The Digitalization of Russian Politics and Political Participation

Peer reviewe

Structural and spatially-resolved studies on the hardening of a commercial resin-modified glass-ionomer cement

A commercial photopolymerizable resinmodified glass-ionomer (Fuji II LC) was studied using a variety of nuclear magnetic resonance (NMR) techniques. H and F stray-field imaging (STRAFI) enabled to follow the acid–base reaction kinetics in self-cured (SC) samples. Gelation and maturation processes with 25 min and 40 h average time constants, respectively, were distinguished. In self- & photo-cured (SPC) samples, two processes were also observed, which occurred with 2 s and 47 s average time constants. H, Al and Si magic angle spinning (MAS) NMR, C cross-polarization (CP)/MAS NMR and 27Al multiple quanta (MQ)MAS NMR spectroscopy were used to obtain structural information on the glass and cements that were either SC or SPC. The presence of methacrylate groups was identified in the solid component. Unreacted hydroxyl ethylmethacrylate (HEMA) was detected in self-cured cement. Al data showed that approximately 28% and 20% of Al is leached out from glass particles in SC and SPC samples, respectively. The upfield shift detected in 25Si MAS NMR spectra of the cements is consistent with a decrease in the number of Al species in the second coordination sphere of the silicon structures. Scanning electron microscopy (SEM) showed existence of 3D shrinkage of the cement matrix in photo-cured cements.(undefined