An alternative index to ESP to explain dispersion occurring in Australian soils when Na content is low

Re-use of industrial and agricultural wastewater for irrigation can increase the concentration of potassium in soil and affect soil structure. However, investigations of clay dispersion have traditionally focused on soils with high exchangeable sodium, therefore exchangeable sodium percentage (ESP) has been used to assess soil structural stability. Currently, Australian soils have been considered non-sodic or non-dispersive when the soil ESP <6. However, a few studies have demonstrated that potassium (K) ions in the exchange complex of soil can also assist clay dispersion even when the exchangeable sodium (Na) levels are minimal. The dispersion (as turbidity) and ESP were measured on 74 Australian soils. 17 of those soils showed a considerable level of dispersion, despite ESP <4.5. In all of these soils the Na to K ratio was <1. The relationships between ESP and turbidity were poor (R2= 0.23) indicating limitations of using the ESP for identifying potentially dispersive soils when K is present on the soil exchange sites. Therefore, we used exchangeable cation ratio (ECR), as an index alternative to ESP, but which takes into account effects of exchangeable K on clay dispersion. The good correlation obtained between ECR and the parameters like turbidity and zeta potential support its use in assessing soil structural stability when the appreciable amount of K present on exchange sites

Solving the difference initial-boundary value problems by the operator exponential method

We suggest a modification of the operator exponential method for the numerical solving the difference linear initial boundary value problems. The scheme is based on the representation of the difference operator for given boundary conditions as the perturbation of the same operator for periodic ones. We analyze the error, stability and efficiency of the scheme for a model example of the one-dimensional operator of second difference

ANALYSIS OF THE CHEMICAL COMPOSITION OF CHAROITE ROCKS

The unique charoite mineralization, established on the Murun alkaline massif in the northwestern part of the Aldan shield on the border of the Irkutsk region and Yakutia, is still of great interest to some of researchers (geologists, crystallographers, geochemists, etc.). The outcrops of charoite-bearing rocks at the “Sirenevyi Kamen” deposit are noted both in the indigenous outcrops and in eluvial clatters [Bondarenko, 2009].The unique charoite mineralization, established on the Murun alkaline massif in the northwestern part of the Aldan shield on the border of the Irkutsk region and Yakutia, is still of great interest to some of researchers (geologists, crystallographers, geochemists, etc.). The outcrops of charoite-bearing rocks at the “Sirenevyi Kamen” deposit are noted both in the indigenous outcrops and in eluvial clatters [Bondarenko, 2009]

The possible evolution of pitch angles of spiral galaxies

The origin and maintenance of spiral structure in galaxies, the correlation between different types of spiral structure and several proposed mechanisms for their generation, and the evolution of spiral arms of galaxies with time are questions that are still controversial. In this note we study the spiral structure in a sample of distant galaxies in order to infer the evolution of spiral arm characteristics with redshift. We considered a sample of 171 face-on spiral galaxies in the Hubble Space Telescope COSMOS (The Cosmic Evolution Survey) field. The galaxies are distributed up to $z \approx 1$ with a mean value of 0.44. For all galaxies, we determined the pitch angles of the spiral arms and analysed their dependence on redshift; a total of 359 arms were measured. Analyses of our measurements combined with the literature data suggest a possible evolution of the pitch angles of spiral galaxies: by the modern epoch the spiral pattern, on average, becomes more tightly wound. This may be a consequence of the general evolution of the structure of galaxies as galaxies become more massive over time and their bulges grow. In addition, the distribution of the cotangent of pitch angle of galaxies indicates the possibility that the dominant mechanism of spiral pattern generation changes over time.Comment: 5 pages, accepted for publication on Astronomy & Astrophysics Letter

Modern information technologies in formation of physical education of the students

The use of information technologies in the study of discipline "Physical culture" will allow to raise interest of students to acquire knowledge and to activate cognitive activity, will contribute to the formation of physical education and cultural competencesИспользование информационных технологий при изучении дисциплины «Физическая культура» позволит повысить интерес у студентов к получению знаний, активизировать познавательную деятельность, будет способствовать формированию физкультурной образованности и общекультурных компетенци

Influence of Physical Education on Mental Activity of Students

Изучение влияния физической активности на психические процессы студентов, имеет актуальное значение, так как связано с их механизмом влияния на успешность учебной деятельности в период обучения в вузе. Целью работы явилось изучение особенностей влияния физкультуры на мыслительные процессы студентов. Рассмотрены факторы, оказывающие прямое и косвенное влияние на мыслительную деятельность студента. Выявленные особенности позволили предложить рекомендации повышения уровня познавательных процессов у молодых людей.The study of the influence of physical activity on the mental processes of students is of current importance, as it is associated with their mechanism of influence on the success of educational activities during their studies at the university. The purpose of the work was to study the features of the influence of physical education on the thought processes of students. The factors that have a direct and indirect influence on the student’s mental activity are considered. The identified features made it possible to propose recommendations for increasing the level of cognitive processes in young people