No abstract

The Gruenberg--Kegel graph $\Gamma(G)$ of a finite group $G$ is the graph whose vertex set is the set of prime divisors of $|G|$ and in which two distinct vertices $r$ and $s$ are adjacent if and only if there exists an element of order $rs$ in $G$. A finite group $G$ is called {\it almost recognizable} (by Gruenberg--Kegel graph) ifthere is only finite number of pairwise non-isomorphic finite groups havingGruenberg--Kegel graph as $G$. If $G$ is not almost recognizable, then it is called {\it unrecognizable}(by Gruenberg--Kegel graph). Recently P.~J.~Cameron and the first author have proved that if a finite group is almost recognizable, then the group is almost simple. Thus, the question of which almost simple groups (in particular, finite simple groups) are almost recognizable is of prime interest. We prove that every finite simple exceptional group of Lie type,which is isomorphic to neither ${^2}B_2(2^{2n+1})$ with $n\geq1$ nor $G_2(3)$ and whose Gruenberg--Kegel graph has at least three connected components, is almost recognizable. Moreover, groups $ {^2}B_2(2^{2n+1})$, where $n\geq1$, and $G_2(3)$ are unrecognizable.

unrecognizable by spectrum (Gruenberg-Kegel graph, respectively), if there are infinitely many pairwise non-isomorphic groups with the same spectrum (Gruenberg-Kegel graph, respectively) as G.

In connection with the intensive mineral resource development, it is now topically relevant to 3cinserve the gene pool of plant rare species, whose populations find themselves within the exclusion zones (quarry mining, disposal of overburden and waste rocks, etc.). However, methods for moving plants from such zones to safe places in order to create artificial populations are still poorly developed. In Bashkortostan, tests are being undertaken to develop the methods for creating rare species artificial populations, including tick trefoils, such as Hedysarum grandiflorum Pall. and H. razoumovianum Fisch. et Helm. These species are included into the Red Data Books of the Republic of Bashkortostan and the Russian Federation. The works are being performed in the Natural Botanical Garden (natural protected area “Gurovskaya Gora” near Ufa). The aim of the research is to develop the methods for evacuating rare species and to create artificial populations and source nurseries for obtaining seeds and planting materials in order to conduct reintroduction works in the crucially endangered populations. In the test with H. grandiflorum we used 15 specimens from different places of Bashkortostan, among them from two sites where mining works are planned to be launched. The number of testing plots created since 2006 is 53. Seedlings are recorded during the first 4-6 years of observation. A massive loss of young plants is observed. Generative plants and self-seeding occur in the majority of the tests. Six specimens of H. razoumovianum are under investigation. Starting in 2005, 17 tests have been undertaken. Seedlings are recorded during 4-6 years. Generative plants emerge in the fourth or fifth year of observation. These plants bloom, produce fruits and self-seed every year. By 2014, two self-reproducing micropopulations have been formed. In 2017, 487 plants were recorde4d in one of them, with 24 maternal plants. The tests suggest the possibility to create artificial populations of these species and to conserve them under eco-phytocoenotic conditions comparable to those in nature. Even now they can serve as the seed source for the reintroduction works.

The paper presents an original method for the template synthesis of biomimetic porous composites using polyferrophenylsiloxane (PFPS) and the skeleton of the sea urchin Strongylocentrotus intermedius as a structuring template. The study aimed to form an organosilicon base of a composite with an inverted structure relative to the original structure of the sea urchin shell with a period of structure movement of about 20 µm and ceramic composites fabrication with the silicate base with an average pore size distribution of about 10 μm obtained by the reaction of PFPS with the inorganic base of the sea urchin test under conditions of calcination at 1000 °C followed by acid etching. The composition and morphology of the obtained composites were investigated by IR, XRD, XPS, EDX, and SEM techniques and by mercury porosimetry; the parameters of the porous structures depend on the selected methods of their synthesis. The proposed method is of fundamental importance for developing methods for the chemical synthesis of new biomimetics with a unique porosity architecture based on environmentally friendly natural raw materials for a vast practical application.