Relativistic calculations of charge transfer probabilities in U92+ - U91+(1s) collisions using the basis set of cubic Hermite splines

A new approach for solving the time-dependent two-center Dirac equation is presented. The method is based on using the finite basis set of cubic Hermite splines on a two-dimensional lattice. The Dirac equation is treated in rotating reference frame. The collision of U92+ (as a projectile) and U91+ (as a target) is considered at energy E_lab=6 MeV/u. The charge transfer probabilities are calculated for different values of the impact parameter. The obtained results are compared with the previous calculations [I. I. Tupitsyn et al., Phys. Rev. A 82, 042701 (2010)], where a method based on atomic-like Dirac-Sturm orbitals was employed. This work can provide a new tool for investigation of quantum electrodynamics effects in heavy-ion collisions near the supercritical regime

Relativistic calculations of the U91+(1s)-U92+ collision using the finite basis set of cubic Hermite splines on a lattice in coordinate space

A new method for solving the time-dependent two-center Dirac equation is developed. The approach is based on the using of the finite basis of cubic Hermite splines on a three-dimensional lattice in the coordinate space. The relativistic calculations of the excitation and charge-transfer probabilities in the U91+(1s)-U92+ collisions in two and three dimensional approaches are performed. The obtained results are compared with our previous calculations employing the Dirac-Sturm basis sets [I.I. Tupitsyn et al., Phys. Rev. A 82, 042701 (2010)]. The role of the negative-energy Dirac spectrum is investigated within the monopole approximation

Model of ionic currents through microtubule nanopores and the lumen

It has been suggested that microtubules and other cytoskeletal filaments may act as electrical transmission lines. An electrical circuit model of the microtubule is constructed incorporating features of its cylindrical structure with nanopores in its walls. This model is used to study how ionic conductance along the lumen is affected by flux through the nanopores when an external potential is applied across its two ends. Based on the results of Brownian dynamics simulations, the nanopores were found to have asymmetric inner and outer conductances, manifested as nonlinear IV curves. Our simulations indicate that a combination of this asymmetry and an internal voltage source arising from the motion of the C-terminal tails causes a net current to be pumped across the microtubule wall and propagate down the microtubule through the lumen. This effect is demonstrated to enhance and add directly to the longitudinal current through the lumen resulting from an external voltage source, and could be significant in amplifying low-intensity endogenous currents within the cellular environment or as a nano-bioelectronic device.Comment: 43 pages, 6 figures, revised versio

Evaluation of siltation of rivers with intensive economic development of watersheds

In regions with a high degree of agricultural development with an active development of erosion processes and the critical level of degradation of the river network to which the Middle-Russian Upland belongs, the evaluation of sedimentation for various combinations of natural and economic conditions becomes an immediate proble

On the water-bag model of dispersionless KP hierarchy

We investigate the bi-Hamiltonian structure of the waterbag model of dKP for two component case. One can establish the third-order and first-order Hamiltonian operator associated with the waterbag model. Also, the dispersive corrections are discussed.Comment: 19 page

Anthropogenic transformation of the flora of urbanoecosystems of the Northern Pryazov territories

This paper provides a thorough analysis of the current state of biodiversity of a model city in the Northern Pre-Azov region ofUkraine– Henichesk (Khersonregion). The species composition of the urban flora of this city is presented here for the first time. There are 507 species, which belong to two divisions, 61 families and 233 genera. The urban flora was analyzed in its systematic, biomorphological and environmental aspects. The species richness of families of the studied urban flora is characterized by a predominance of families which include 1–2 species. The majority of the urban flora species are herbaceous plants – 80.1% (406 species), including herbaceous monocarpics – 236 species and herbaceous polycarpics – 170. It was found that the ecological category with the largest number of species was therophytes l – 36.1% of species in the urban flora of Henichesk, the second place taken by hemicryptophytes – 31.9%. Other biological types are represented in a small quantity – 32.0%. An important characteristic of flora is distribution of species according to the main vegetation types (rythmologic groups). Summer green plants – 430 species (84.8%) are the dominant group in the researched urban flora. The plant community includes differentiated rosette, semirosette and rosetteless plants. Species with rosetteless shoot dominate. Rhizomeless species dominate in the flora of Henichesk (51.1%) and species with caudex (23.6%), indicating the dominance of xerophytic habitats and increased soil density in cities. In terms of moisture requirements, the largest environmental group is that which requires moderate moisture, accounting for 349 species (68.8% of the total species number). Heliophyllous, shade-tolerant species, and mezotrophs dominate. The adventive component of the Henichesk flora includes 217 species (159 genera and 52 families). Most of them are kenophytes, xenophytes, epecophytes. It was found that Henichesk has a specific urban flora that combines elements of natural flora and typical urban components.The paper provides a thorough analysis of the current situation about biodiversity of model city in the Nothern Pryazov territories – Henichesk (Kherson region). The urban flora species composition of this city is represented at first time. There are 507 species, which belongs to two divisions, 61 families and 233 genera. Urban flora was analyzed in systematical, biomorphological and environmental aspects. The species richness of families of the studied urban flora is characterized by a predominance of families which include 1–2 species. The most part of urban flora species are herbaceous plants – 80.1% (406 species), including herbaceous monocarpics – 236 species and herbaceous policarpics – 170. It was found that terophytes have prevalence – 36.1% by the types of biological species in the urban flora of Henichesk, the second place takes hemicryptophytes – 31.9%. Other biological types are represented in a small quantity – 32%. An important characteristic of flora is species distribution for the main types of vegetation (rythmologic groups). The dominated status in the researched urban flora set the summer green plants – 430 species (84.8%). Analyzing the position of the aerial shoot for the leaves position we have differed rosette, semirosette and rosetteless plants. Species with rosetteless shoot are dominating. Rhizomeless species in the flora of Henichesk are dominating (51.1%) and species with caudex (23.6%), indicating the dominance of xerophytic habitats and increased soil density in cities. The largest environmental group is a group of moderate moisture, which consists of 349 species (68.8% of the total species number). There is predominance of heliophilous and shade-tolerant species, and mezotrophs. Adventive component of Henichesk flora has 217 species (159 genera and 52 families). The most part among them kenophytes, xenophytes, epecophytes. It was found that Henichesk have specific urban flora that combines elements of natural flora and typical urban components.&nbsp

Use of soil biota in the assessment of the ecological potential of urban soils

In assessing the ecological conditions and classification of urban soils, data about soil biota should be taken into account. The environment of urban territories is characterized by significant changes compared to their surrounding environments. It is established that the algal flora of urban soils lose their zonal features and features associated with the edification influence of higher plants. Specific biotopes with a definite species structure are formed in urboecosystems. Fifty 50 algae species have been recorded in the soils of the Henichesk urboecosystems (Kherson region, Ukraine): Cyanoprocaryota – 21, Chlorophyta – 13, Charophyta – 2, Eustigmatophyta – 1, Xanthophyta – 11, Bacillariophyta – 2. Among dominant and subdominant species were Cyanoprocaryota and Chlorophyta. The other phyla were represented by Klebsormidium dissectum, K. flaccidum, Hantzschia amphioxys, Eustigmatos magnus, Botrydiopsis eriensis. Compared with the surrounding environment, the urbanized flora of Henichesk has a low species richness, and is characterized by prevalence of Cyanoprocaryota and Chlorophyta species. The coefficient that takes into account the percentage of preservation of species richness in a particular urban area compared to the background indicators of species richness can be used to evaluate the urban transformation of soil biota. The degree of degradatory changes in the composition of living organisms and the direction of these changes depends on the specificity and intensity of exploitation of the territory of the urban ecosystem. The most diverse composition of algae species within the the city of Henichesk was noted in the recreational, residential, and transport zones, in comparison with the industrial zone and the zone of special use. Different functional areas of the city are distinguished not only by the algae species richness, but also by the composition of dominants. Among the dominants and subdominants of the recreational and transport zones were species of different phyla. The dominants and subdominants of the residential and industrial zones were Cyanoprocaryota species, in the zone of special use – representatives of Chlorophyta. The distribution of species richness of algae along the soil profile in the city acquires an atypical character. The species richness increases not in the most superficial layers of soil, but in the lower, aphotic parts of the soil profile. The soil biota, on the one hand, depends on the ecological conditions of soil, and on the other as a result of its life activity, changes the ecological functions of the soil, strengthening or weakening them. The reduction in the species richness of the soil algae of the urboecosystem Henichesk shows the limitations of ecological functions of urban soils. It is established that changes in the composition of algae in soils of urban ecosystems are one of the indicators of the presence and severity of transformation processes. These processes occur with the soil biota and soil as a whole under the conditions of urban ecosystems and can be used as indicators in the environmental assessment of urban soils, in the development and subsequent examination of ways to reduce negative expression of urbanization