Electronic origin of the incommensurate modulation in the structure of phosphorus IV

An incommensurate modulated structure was found recently in a light group V element phosphorous in the phase P-IV stable in the pressure range 107-137 GPa. We consider configurations of the Brillouin zone and Fermi sphere within a nearly-free-electron model in order to analyze the importance of these configurations for the crystal structure energy. For the phase P-IV with the base-centered orthorhombic structure, oC2, we consider a commensurate approximant with an 11-fold supercell along the c-axis and a modulation wave vector equal 3/11 which is close to the experimentally observed value of 0.267. Atomic shifts due to the modulation result in appearance of satellite reflections and hence in a formation of additional Brillouin zone planes. The stability of this structure is attributed to the lowering of the electronic band structure energy due to Brillouin zone - Fermi surface interactions

Structure stability in the simple element sodium under pressure

The simple alkali metal Na, that crystallizes in a body-centred cubic structure at ambient pressure, exhibits a wealth of complex phases at extreme conditions as found by experimental studies. The analysis of the mechanism of stabilization of some of these phases, namely, the low-temperature Sm-type phase and the high-pressure cI16 and oP8 phases, shows that they satisfy the criteria for the Hume-Rothery mechanism. These phases appear to be stabilized due to a formation of numerous planes in a Brillouin-Jones zone in the vicinity of the Fermi sphere of Na, which leads to the reduction of the overall electronic energy. For the oP8 phase, this mechanism seems to be working if one assumes that Na becomes divalent metal at this density. The oP8 phase of Na is analysed in comparison with the MnP-type oP8 phases known in binary compounds, as well as in relation to the hP4 structure of the NiAs-type

Numerical studies of steel channels with staggered slotted perforations subject to combined bending and shear actions

Cold-formed steel studs and purlins with staggered slotted perforations in webs are used in construction to improve thermal performance of the profiles and energy efficiency of structures. On the other hand, the web perforations adversely affect structural performance of the members, especially their shear, bending and combined bending and shear strengths. Relatively little research has been reported on this subject despite its importance. Many research studies have been carried out to evaluate the combined bending and shear behaviour of conventional cold-formed channel beams. To date, however, no investigation has been conducted into the strength of cold-formed steel channels with staggered slotted perforations under combined bending and shear actions. Finite element models of cold-formed steel channels with staggered slotted perforations were developed to simulate their combined bending and shear behaviour and strength. They were then validated by comparing the results with available experimental test results and used in a detailed parametric study. This paper presents the details of the numerical studies of cold-formed steel channels with staggered slotted perforations and the results

SOCIALIZAÇÃO DE FUTUROS ESPECIALISTAS NO CONTEXTO DA ABORDAGEM POR COMPETÊNCIAS

The solution of the problems facing the modern Russian society largely depends on the beliefs, expectations, values and attitudes of people that determine their attitude to innovation, content, effectiveness and efficiency of various activities. Social adaptation (active inclusion in the social environment) of the individual assumes as a necessary condition the achievement of a certain level of social competence. The modern social environment has a significant impact on the process of personality formation, causing certain contradictions: on the one hand, socio-cultural modernization necessitates a new approach to the problem of social self-realization of the individual, requiring increased human activity as a subject of social life, taking responsibility for their activities and behavior, but, on the other hand, the instability of modern society increases the natural difficulties of growing up; the situation of uncertainty leads to deformation of personal development, disadaptation in society. Modernization of the education system has led to changes in the content, forms, methods and technologies of education, in connection with which there was a need to assess the results of the functioning of the education system. Analyzing the quality of a modern specialist training, researchers increasingly began to turn to the competencies formed during studying, among which an important place is occupied by social competence, estimated as the most important indicator of professional competence of a specialist in general, and in particular, in the field of economic, labor, social relations.A solução dos problemas enfrentados pela sociedade russa moderna depende em grande parte das crenças, expectativas, valores e atitudes das pessoas que determinam sua atitude em relação à inovação, conteúdo, eficácia e eficiência de várias atividades. A adaptação social (inclusão ativa no ambiente social) do indivíduo assume como condição necessária a conquista de um certo nível de competência social. O ambiente social moderno tem um impacto significativo no processo de formação da personalidade, causando certas contradições: por um lado, a modernização sociocultural requer uma nova abordagem para o problema da auto- realização social do indivíduo, exigindo maior atividade humana como sujeito da vida social, assumindo a responsabilidade por suas atividades e comportamentos, mas, por outro lado, a instabilidade da sociedade moderna aumenta as dificuldades naturais de crescer; a situação de incerteza leva à deformação do desenvolvimento pessoal, à desadaptação na sociedade. A modernização do sistema educacional levou a mudanças no conteúdo, formas, métodos e tecnologias da educação, em relação às quais havia a necessidade de avaliar os resultados do funcionamento do sistema educacional. Analisando a qualidade de um treinamento especializado moderno, os pesquisadores começaram a recorrer cada vez mais às competências formadas durante o estudo, entre as quais um lugar importante é ocupado pela competência social, estimado como o indicador mais importante da competência profissional de um especialista em geral e, em particular, , no campo das relações econômicas, trabalhistas e sociais.La solución de los problemas que enfrenta la sociedad rusa moderna depende en gran medida de las creencias, expectativas, valores y actitudes de las personas que determinan su actitud hacia la innovación, el contenido, la efectividad y la eficiencia de diversas actividades. La adaptación social (inclusión activa en el entorno social) del individuo supone como condición necesaria el logro de un cierto nivel de competencia social. El entorno social moderno tiene un impacto significativo en el proceso de formación de la personalidad, causando ciertas contradicciones: por un lado, la modernización sociocultural requiere un nuevo enfoque del problema de la autorrealización social del individuo, que requiere una mayor actividad humana como un sujeto de la vida social, asumiendo la responsabilidad de sus actividades y comportamiento, pero, por otro lado, la inestabilidad de la sociedad moderna aumenta las dificultades naturales de crecer; La situación de incertidumbre conduce a la deformación del desarrollo personal, la desadaptación en la sociedad. La modernización del sistema educativo ha llevado a cambios en el contenido, las formas, los métodos y las tecnologías de la educación, en relación con lo cual era necesario evaluar los resultados del funcionamiento del sistema educativo. Analizando la calidad de una formación especializada moderna, los investigadores comenzaron a recurrir cada vez más a las competencias formadas durante el estudio, entre las cuales un lugar importante está ocupado por la competencia social, estimado como el indicador más importante de la competencia profesional de un especialista en general, y en particular , en el campo de las relaciones económicas, laborales, sociales

Approaches to the construction of simulation model of the process optimization of rare plants microclonal propagation

The authors present approaches to constructing an imitation model for the optimization of the process of rare plants microclonal reproduction (on the example of the Belgorod region), which allow to identify the most effective ways of explants sterilization, to define the optimal composition of nutrient media for regenerants growth (tube plants) and growth regulators (phytohormones) for propagation of mini-plant

Origin of complex crystal structures of elements at pressure

We present a unifying theory for the observed complex structures of the sp-bonded elements under pressure based on nearly free electron picture (NFE). In the intermediate pressure regime the dominant contribution to crystal structure arises from Fermi-surface Brillouin zone (FSBZ) interactions - structures which allow this are favoured. This simple theory explains the observed crystal structures, transport properties, the evolution of internal and unit cell parameters with pressure. We illustrate it with experimental data for these elements and ab initio calculation for Li.Comment: 4 pages 5 figure

Effect of pressure on the Raman modes of antimony

The effect of pressure on the zone-center optical phonon modes of antimony in the A7 structure has been investigated by Raman spectroscopy. The A_g and E_g frequencies exhibit a pronounced softening with increasing pressure, the effect being related to a gradual suppression of the Peierls-like distortion of the A7 phase relative to a cubic primitive lattice. Also, both Raman modes broaden significantly under pressure. Spectra taken at low temperature indicate that the broadening is at least partly caused by phonon-phonon interactions. We also report results of ab initio frozen-phonon calculations of the A_g and E_g mode frequencies. Presence of strong anharmonicity is clearly apparent in calculated total energy versus atom displacement relations. Pronounced nonlinearities in the force versus displacement relations are observed. Structural instabilities of the Sb-A7 phase are briefly addressed in the Appendix.Comment: 10 pages, 8 figure

Nanostructured water-phosphorite suspension is a new promising fertilizer

© Pleiades Publishing, Ltd., 2015. A rival import-substituting biosafe nanofertilizer, a nanostructured water-phosphorite suspension with a particle size of 60.0-120.0 nm, has been obtained for the first time from the natural raw phosphorite of Tatarstan’s Syundyukovskoe deposits by ultrasonic material dispersion. The nanofertilizer is shown to have no acute phytotoxicity against nine test plants at the rates of 0.25-10.0 kg per ton of seeds and no toxic or mutagenic properties against the microbiological test system at concentrations of 0.2-200.0 μg/mL. In greenhouse, field, and farm-scale trials of agricultural crops under open and protected ground conditions, different methods and rates of nanofertilizer application are studied to show the high efficiency of the nanostructrured water-phosphorite suspension upon soil fertilization at a rate of 1.0 t/ha and presowing treatment of seeds at a rate of 1.25 kg/t of seeds. It is established that the morphometric indices of plants increases from 8.3% to 3.5-fold, the fresh yield increases from 2.4% to 2.2-fold, and the fruit yield increases from 14.5 to 24.1%. The improvement in crop production quality by a set of indices from 0.3% to 2.6-fold was noted

Clinical and pharmacological basis of the use of testosterone drugs for hormonal replacement therapy for hypogonadism in men

Hypogonadism is a condition associated with a decrease in the functional activity of the testicles, accompanied by a decrease in the level of androgens and (or) a violation of the process of spermatogenesis. It is known that androgens and their main representative, testosterone, are of fundamental importance for the development and maintenance of the reproductive and sexual functions of the male reproductive system. At the same time, low testosterone levels are associated with both reproductive and metabolic disorders, including phosphorus-calcium, fat, carbohydrate, and protein metabolism. In addition, to date, data have been accumulated on the correlation of hypogonadism with cardiovascular diseases, which once again emphasizes the problem of testosterone deficiency, especially for patients of the middle and older age groups. However, carrying out testosterone replacement therapy always requires a strict and competent choice of a «target audience» among patients from a specialist. Today, on the pharmaceutical market, there is a wide arsenal of testosterone-containing drugs in various forms for use, which have an unequal «efficacy-safety» profile. In this review, we have analyzed modern approaches to the diagnosis and treatment of hypogonadism, the selection of a target group of patients to obtain the most effective and safe treatment outcome and described testosterone preparations and their dosage forms with potential advantages and disadvantages. Thus, the information presented in the article is aimed at optimizing the management of men with hypogonadism