The atmosphere as a lens

The advent of manned satellites has made it possible for man to observe Earth from great distances. Many new phenomena have been discovered in the atmosphere. These are evidently caused by reflection, scattering or refraction of light on crystals and drops of water. It is possible to see small objects on the surface of Earth because of these anomalies

On finite groups with disconnected prime graph

All finite simple nonabelian groups that have the same prime graph as a Frobenius group or a 2-Frobenius group are found. © 2013 Pleiades Publishing, Ltd

Interpretation of contradictory images by means of systems of linear inequalities

We consider the problem of interpretation of three-dimensional images from their flat projections up to the set of visible faces. For projections of convex polyhedra, we present an interpretation algorithm based on maximal feasible subsystems of a certain infeasible system of linear inequalities modeling the visibility requirement for faces. A number of model examples are given; in particular, the algorithm is applied to the interpretation of the Necker cube. © 2013 Pleiades Publishing, Ltd

Unsolved Problems in Group Theory. The Kourovka Notebook

This is a collection of open problems in group theory proposed by hundreds of mathematicians from all over the world. It has been published every 2-4 years in Novosibirsk since 1965. This is the 19th edition, which contains 111 new problems and a number of comments on about 1000 problems from the previous editions.Comment: A few new solutions and references have been added or update

Minimal Committee Problem for Inconsistent Systems of Linear Inequalities on the Plane

A representation of an arbitrary system of strict linear inequalities in R^n as a system of points is proposed. The representation is obtained by using a so-called polarity. Based on this representation an algorithm for constructing a committee solution of an inconsistent plane system of linear inequalities is given. A solution of two problems on minimal committee of a plane system is proposed. The obtained solutions to these problems can be found by means of the proposed algorithm.Comment: 29 pages, 2 figure

Finite groups isospectral to simple groups

The spectrum of a finite group is the set of element orders of this group. The main goal of this paper is to survey results concerning recognition of finite simple groups by spectrum, in particular, to list all finite simple groups for which the recognition problem is solved

ОБОРОТ ТРОМБОЦИТОВ И АТЕРОТРОМБОЗ

Platelets play an important role in initiating atherothrombosis, i.e. the formation of blood clots inside a blood vessel at areas of atherosclerotic vascular injury. The functional (prothrombotic) activity of platelets significantly varies both in healthy individuals and in patients with cardiovascular diseases. The increased platelet production and turnover may be one of the reasons for promoting platelet activity. Stimulating thrombocytopoiesis results in large and reticular (with an increased amount of RNA) "young" platelets in the bloodstream. These platelets contain more adhesive receptors, more secretory granules and have an increased aggregation capacity. The review provides data indicating that large and reticular platelets are not only markers, but also predictors of atherothrombotic events, and primarily of acute coronary syndrome. An increase in such platelet count in patients receiving antiplatelet drugs is associated with a decrease in effectiveness of their antiplatelet action. It is assumed that the appearance of large and reticular platelets in the blood of patients with atherosclerosis and atherothrombosis may be a consequence of an increase in the thrombopoietic activity of megakaryocytes in these pathological conditions.Тромбоциты играют ведущую роль в инициации атеротромбоза – образования внутрисосудистых тромбов в участках атеросклеротическом повреждении сосудов. Функциональная (протромботическая) активность тромбоцитов существенным образом варьирует как у здоровых лиц, так и у пациентов с сердечно-сосудистыми заболеваниями. Одной из причин повышения активности тромбоцитов может быть ускорение их продукции и оборота. При стимуляции тромбоцитопоэза в кровотоке появляются крупные и ретикулярные (с повышенным количеством РНК) «молодые» тромбоциты. Эти тромбоциты содержат больше адгезивных рецепторов, больше секреторных гранул и обладают повышенной способностью к агрегации. В обзоре приводятся данные, указывающие на то, что крупные и ретикулярные тромбоциты являются не только маркерами, но и предикторами атеротромботических событий, и в первую очередь острого коронарного синдрома. Увеличение количества таких тромбоцитов у больных, получающих антитромбоцитарные препараты, ассоциировано со снижением эффективности их антиагрегантного действия. Предполагается, что появление крупных и ретикулярных тромбоцитов в крови больных с атеросклерозом и атеротромбозом может быть следствием повышения тромбопоэтической активности мегакариоцитов при этих патологических состояниях

Cold-seep carbonates of the Laptev Sea continental slope: Constraints from fluid sources and environment of formation

This study presents results of the petrographic, mineralogical, stable isotopes of oxygen and carbon, and trace element investigation of authigenic carbonates collected at newly discovered active cold seeps on the Laptev Sea continental slope at ∼300 m water depth. These carbonates are mainly represented by Mg-calcite with MgCO3 content from 9.1 mol% to 14.0 mol%. The low δ13C values of carbonates ranging from −50.6 ‰ to −32.4 ‰ (V-PDB) indicate that they were formed from anaerobic oxidation of biogenic methane and minor participation of other carbon sources. The difference between measured (from 4.7 ‰ to 5.5 ‰) and calculated (4.0 ‰) δ18Ocarb values might be inherited from fluids enriched in 18O due to dissociation of gas hydrates, which could be the source of methane. The carbonates exhibit weak enrichment in Co, moderate and strong enrichments in As, Mo, and Sb, and strong enrichment in U. Interestingly, As, Sb, and Co correlate with the pyrite content. This indicates that authigenic iron sulfides promote the immobilization of these redox-sensitive elements in seep sediments. The (Mo/U)EF values and anomalies of concentration of Mo and U probably indicate variations in the redox conditions during carbonate formation due to episodically seepage activity changes. Ascending methane-bearing fluids were the main contributor to the enrichment of cold-seep carbonates in As, Mo, Sb, and U at the Laptev Sea continental slope. However additional input from the particulate shuttle process can not be ruled out

Stimulation of platelet glycoprotein IIb-IIIa (αIIbβ3-integrin) functional activity by a monoclonal antibody to the N-terminal region of glycoprotein IIIa

AbstractPlatelet glycoprotein (GP) IIb-IIIa complex (αIIbβ3-integrin) changes its conformation upon platelet activation that results in binding of RGD-containing ligands and expression of ligand-induced binding site (LIBS) neoepitopes. Anti-GIIb-IIIa monoclonal antibody (monAB) CRC54 bound to ≤10% of GPIIb-IIIa on resting platelets but binding was enhanced by the occupation of GPIIb-IIIa with RGDS peptide and by platelet activation indicating that CRC54 is directed against LIBS epitope. The epitope was located within the first 100 N-terminal residues of GPIIIa and differed from other LIBS epitopes. CRC54 as well as its Fab fragments were able to induce platelet aggregation. CRC54 also stimulated interaction of GPIIb-IIIa with its ligands (fibrinogen and fibronectin) and conformation-dependent antibodies. The results indicated that changes of GPIIb-IIIa conformation, binding of ligands and platelet aggregation could be stimulated via interaction of anti-LIBS antibody with the N-terminal part of GPIIIa