Floristic Phenomena of the Samara Bend: The Fractal Organization of Taxonomic Diversity

Considering the problem of taxonomic diversity as a fractal object is the aim of this article. The prerequisites for such an approach were articles with varying degrees of detail and argumentation that substantiate taxonomic diversity from the standpoint of fractal geometry. Common to these papers is that the authors in their theoretical constructs start from the Willis rule (law) describing the rank distribution of the relationship between the number of taxa and their volume. The flora of the Samara Bend (the bend of the Volga River in its middle reaches) has become an object of the research. The authors distinguish seven basic floristic areas on the Samara Bend, the boundaries of which coincide with the respective landscapes. The authors discuss the efficiency of the Willis rule (law), which approximates the relationship between the number of taxa and their volume by rank distribution. The multifractal spectrum (a generalized geometric image of generic structure) of the taxonomic diversity of vascular plants of the Samara Bend is presented. Keywords: taxonomic diversity, fractal organization, Samara Ben

Weak splittings of quotients of Drinfeld and Heisenberg doubles

We investigate the fine structure of the simplectic foliations of Poisson homogeneous spaces. Two general results are proved for weak splittings of surjective Poisson submersions from Heisenberg and Drinfeld doubles. The implications of these results are that the torus orbits of symplectic leaves of the quotients can be explicitly realized as Poisson-Dirac submanifolds of the torus orbits of the doubles. The results have a wide range of applications to many families of real and complex Poisson structures on flag varieties. Their torus orbits of leaves recover important families of varieties such as the open Richardson varieties.Comment: 20 pages, AMS Late

Accelerated synthesis of Sn-BEA in fluoride media:effect of H₂O content in the gel

Sn-BEA synthesis in concentrated gels results in 2.5–4 fold reduction of crystallization time and formation of smaller zeolite crystals.</p

Effects of gama irradiation on nucellar callus production of lhe 'Valência' sweet orange (Citrus sinsensis) Osb. in vitro.

Os métodos convencionais pouco têm contribuído para o melhoramento das espécies cítricas. A utilização das técnicas de cultura in vitro associadas à indução de mutações deverão trazer inestimável contribuição. Nucelos extraídos de frutos em desenvolvimento, doze semanas após a polinização, foram cultivados in vitro em meio "MS" adicionado (em mg/ 1) de: tiamina HCQ - 0,2; piridoxina HCQ - 1,0; ácido nicotínico - 1,0; mesoinositol - 100; extrato de malte - 500; sacarose - 50.000; ágar - 8.000, com pH ajustado para 5,7. Procedeu-se à irradiação, apenas do meio ou do nucelo, ou de ambos, nas doses de 0,0, 0,5, 1,0, 2,0, 4,0, 8.0 e 12,0 kR. A irradiação apenas do nucelo mostrou um efeito similar ao obtido pela irradiação tanto do nucelo como do meio. Doses baixas de radiação (até 2 kR) reduzem o número de embrióides diferenciados. A irradiação do meio de cultura aumenta a proliferação de calos, principalmente em doses mais elevadas.The conventional methods of plant breeding have not given a significative contribution for the citrus breeding. A precious iniprovement by the techniques of tissues culture in vitro, associated with induced mutations, is expected. Nucelli extracted from developping fruits with twelve weeks after pollination were cultured in vitro, on medium supplemented (in mg/ 1) by: thiamine HCQ 0.2; piridoxine HCL 1.0;  icotinic acid 1.0; mesoinositol 100; malt extract; sucrose 50.000; and agar 8.000 with pi-! = 5.7. The irradiation at 0.0; 0.5; 1.0; 2.0; 4.0; 8.0 and 12.0 kR doses was applied on, only medium, only nucellus, and medium and nucellus together. Irradiation of only nucellus and both nucellus and medium, at the same time, showed similar effects. Low doses of irradiation (until 2 kR) decrease the number of differential embryoids. The irradiation of culture medium, mainly at high doses, increases callus proliferatio

Chiral Salts of Phosphorus Dithioacids Based on Quinine

© 2018, Pleiades Publishing, Ltd. Reactions of quinine with dithioacids based on (1R)-endo-(+)-fenchol, (1S)-endo-(–)-borneol, and (S)-(–)-menthol have afforded optically active quinine salts. Chiral diquinine salts have been obtained in the reactions of quinine with bisthiophosphonic acids based on triethylene glycol and resorcinol

Nonregular structure-property relationships for inclusion parameters of tert-butylcalix[5]arene

The effect of macrocycle size on the structure-property relationships was studied for inclusion compounds of tert-butylcalix[n]arenes (n = 4,5) with volatile organic guests having various molecular size and group composition. Vapor-sorption isotherms, guest-inclusion stoichiometry and Gibbs energy, thermostability parameters and decomposition enthalpies were determined for host-guest compounds (clathrates) obtained using saturation of solid calixarene powder with guest vapor. The increase of the host macrocycle in the studied calixarene pair changes the observed structure-property relationship from the guest-binding selectivity mostly seen in inclusion Gibbs energy to the high sensitivity for guest structure in inclusion stoichiometry. The host with the larger macrocycle has more clathrates with stepwise formation and decomposition. Specific types of guest binding with solid hosts are discussed. © The Royal Society of Chemistry

1/f Noise and Extreme Value Statistics

We study the finite-size scaling of the roughness of signals in systems displaying Gaussian 1/f power spectra. It is found that one of the extreme value distributions (Gumbel distribution) emerges as the scaling function when the boundary conditions are periodic. We provide a realistic example of periodic 1/f noise, and demonstrate by simulations that the Gumbel distribution is a good approximation for the case of nonperiodic boundary conditions as well. Experiments on voltage fluctuations in GaAs films are analyzed and excellent agreement is found with the theory.Comment: 4 pages, 4 postscript figures, RevTe

Absorption of Terahertz Radiation in Ge/Si(001) Heterostructures with Quantum Dots

The terahertz spectra of the dynamic conductivity and radiation absorption coefficient in germanium-silicon heterostructures with arrays of Ge hut clusters (quantum dots) have been measured for the first time in the frequency range of 0.3-1.2 THz at room temperature. It has been found that the effective dynamic conductivity and effective radiation absorption coefficient in the heterostructure due to the presence of germanium quantum dots in it are much larger than the respective quantities of both the bulk Ge single crystal and Ge/Si(001) without arrays of quantum dots. The possible microscopic mechanisms of the detected increase in the absorption in arrays of quantum dots have been discussed.Comment: 9 pages, 4 figures; typos correcte

Ferrous iron- and ammonium-rich diffuse vents support habitat-specific communities in a shallow hydrothermal field off the Basiluzzo Islet (Aeolian Volcanic Archipelago)

Ammonium- and Fe(II)-rich fluid flows, known from deep-sea hydrothermal systems, have been extensively studied in the last decades and are considered as sites with high microbial diversity and activity. Their shallow-submarine counterparts, despite their easier accessibility, have so far been under-investigated, and as a consequence, much less is known about microbial communities inhabiting these ecosystems. A field of shallow expulsion of hydrothermal fluids has been discovered at depths of 170-400 meters off the base of the Basiluzzo Islet (Aeolian Volcanic Archipelago, Southern Tyrrhenian Sea). This area consists predominantly of both actively diffusing and inactive 1-3 meters-high structures in the form of vertical pinnacles, steeples and mounds covered by a thick orange to brown crust deposits hosting rich benthic fauna. Integrated morphological, mineralogical, and geochemical analyses revealed that, above all, these crusts are formed by ferrihydrite-type Fe3+ oxyhydroxides. Two cruises in 2013 allowed us to monitor and sampled this novel ecosystem, certainly interesting in terms of shallow-water iron-rich site. The main objective of this work was to characterize the composition of extant communities of iron microbial mats in relation to the environmental setting and the observed patterns of macrofaunal colonization. We demonstrated that iron-rich deposits contain complex and stratified microbial communities with a high proportion of prokaryotes akin to ammonium- and iron-oxidizing chemoautotrophs, belonging to Thaumarchaeota, Nitrospira, and Zetaproteobacteria. Colonizers of iron-rich mounds, while composed of the common macrobenthic grazers, predators, filter-feeders, and tube-dwellers with no representatives of vent endemic fauna, differed from the surrounding populations. Thus, it is very likely that reduced electron donors (Fe2+ and NH4+) are important energy sources in supporting primary production in microbial mats, which form a habitat-specific trophic base of the whole Basiluzzo hydrothermal ecosystem, including macrobenthic fauna