Cluster policy in agrarian sphere in implementation of concept of economic growth

The purpose of the article is to substantiate the necessity and compile recommendations for improvement of the process of development and conduct of cluster policy in agrarian sphere during realization of the concept of economic growth by the example of modern Russia. As methodological provision, the research uses the proprietary methodology of analysis of development of agrarian sphere of economy. As a result of the use of this methodology and analysis of development of agrarian sphere of modern Russian, the authors come to the conclusion that it has a lot of negative tendencies, which causes necessity for improvement of policy in this sphere. For this, the authors offer to use clustering. The authors develop the Pyramid of optimal economic growth and the Model of realization of the concept of economic growth on the basis of conduct of cluster policy in agrarian sphere.peer-reviewe

Polystyrene-based nanocomposites with different fillers: fabrication and mechanical properties

The paper presents a comprehensive analysis of elastic properties of polystyrene-based nanocomposites filled with different types of inclusions: small spherical particles (SiO2 and Al2O3), alumosilicates (montmorillonite, halloysite natural tubules and Mica) and carbon nanofillers (carbon black and multi-walled carbon nanotubes). Composites were fabricated by melt technology. The analysis of composite melts showed that the introduction of Montmorillonite, Multi-walled carbon nanotubes, and Al2O3 particles provided an increase in melt viscosity by an average of 2 to 5 orders of magnitude over the pure polystyrene. Block samples of composites with different filler concentrations were prepared, and their linear and nonlinear elastic properties were studied. The introduction of more rigid particles led to a more profound increase in the elastic modulus of the composite, with the highest rise of about 80% obtained with carbon fillers. Carbon black particles provided also an enhanced strength at break of about 20% higher than that of pure polystyrene. The nonlinear elastic moduli of composites were shown to be more sensitive to addition of filler particles to the polymer matrix than the linear ones. The nonlinearity coefficient $\beta$ comprising the combination of linear and nonlinear elastic moduli of a material demonstrated considerable changes correlating with changes of the Young's modulus. The absolute value of $\beta$ showed rise in 1.5-1.6 times in the CB- and HNT-containing composites as compared to that of pure PS. The changes in nonlinear elasticity of fabricated composites were compared with measurements of the parameters of bulk nonlinear strain waves in them. Variations of wave velocity and decay decrement correlated with observed enhancement of materials nonlinearity

Subsquares Approach - Simple Scheme for Solving Overdetermined Interval Linear Systems

In this work we present a new simple but efficient scheme - Subsquares approach - for development of algorithms for enclosing the solution set of overdetermined interval linear systems. We are going to show two algorithms based on this scheme and discuss their features. We start with a simple algorithm as a motivation, then we continue with a sequential algorithm. Both algorithms can be easily parallelized. The features of both algorithms will be discussed and numerically tested.Comment: submitted to PPAM 201

Unusual Presentation Of Self-Limiting Chorioretinopathy Possibly Associated With COVID-19

The paper reports on an unusual presentation of self-limiting chorioretinopathy possibly associated with COVID-19 in a 47-year-old woman previously tested positive for SARS-COV-2 by PCR, who presented with decreased VA in her right eye on day 15 after testing. The only symptom she had was anosmia and аgeusia. No therapy was taken during the 14-days quarantine period. The anterior segment was unremarkable on slit lamp examination in both eyes. Fundus examination of the left eye showed no significant findings. On the other hand, the examination of the right eye revealed yellowish creamy deep chorioretinal lesion in central retina. Two weeks later the patient came back for follow-up and it was found that the lesion was decreased in size, with VA improvement. Ocular signs in COVID-19 cases are rarely reported, and most of the ophthalmological changes have been associated usually with viral conjunctivitis. Researchers report also finding such as cotton wool spots, microhemorrhages and some OCT-changes. This case illustrates the possible association between COVID-19 and retinopathy despite the almost asymptomatic presentation

Risk factors for the preservation of morphological changes in the gastric mucosa after eradication therapy for Helicobacter pylori infection in children with chronic gastritis

We conducted a clinical, morphofunctional examination and standard treatment of 155 children with chronic gastroduodenitis associated with Helicobacter pylori (HP) infection. It was кevealed that after 6 months lymphoplasmacytic infiltration of the gastric mucosa (GM) preserved in 37% of cases, and unspecified atrophy - in 9%, increased C3 and C4 components of the compliment - in 19% of children, antroduodenal discoordination on the background of postprandial secretin and cholecystokinin level - in 25%, as well as disorders of the intestinal microbiot