Variational principles of micromagnetics revisited

We revisit the basic variational formulation of the minimization problem associated with the micromagnetic energy, with an emphasis on the treatment of the stray field contribution to the energy, which is intrinsically non-local. Under minimal assumptions, we establish three distinct variational principles for the stray field energy: a minimax principle involving magnetic scalar potential and two minimization principles involving magnetic vector potential. We then apply our formulations to the dimension reduction problem for thin ferromagnetic shells of arbitrary shapes

2-[2-(1H-Imidazol-1-yl)-2-adamant­yl]phenol

In the title mol­ecule, C19H22N2O, the imidazole and benzene rings form a dihedral angle of 84.53 (5)°. In the crystal, classical inter­molecular O—H⋯N hydrogen bonds pair the mol­ecules into centrosymmetric dimers, and C—H⋯π inter­actions further link these dimers into columns propagated in [100]

The Effects of Institutional Transformations on the Russian Doctoral Education Performance

Currently, enhancement of doctoral education performance is becoming one of the central tasks for state policy in the field of science and education. In 2013–2015 Russian doctoral education experienced radical transformations aimed to increase the performance of doctoral programs and enhance the quality of dissertations. First, doctoral education moved towards the structured (educational) model. Second, norms and rules of the work of dissertation boards changed significantly. The purpose of this study is to explore how these reforms affected the performance of doctoral education. The empirical base for the study comprises the data on dissertations defense of graduates of 2018 at 12 Russian universities (N=1022), which were collected by the authors using the web scraping technique. The main findings obtained from the analysis of these data are threefold. First, time-to-degree has increased with most of the dissertations now being defended only after the completion of the programs. Second, in social sciences, this delay of defense has intensified abnormally (80% of dissertation in this field are defended after the program completion). Third, the actual performance, i.e., one that takes into account dissertations defended after the program completion, has decreased significantly in social sciences and humanities. These results show that the traditional practice to evaluate performance based on the proportion of graduates who defend their dissertations during the normative period of time does not reflect the reality. To made adequate managerial decisions regarding doctoral education, it is necessary to arrange the monitoring of dynamics of dissertations that are defended after the program completion both on institution and state levels

Exact Self-consistent Particle-like Solutions to the Equations of Nonlinear Scalar Electrodynamics in General Relativity

Exact self-consistent particle-like solutions with spherical and/or cylindrical symmetry to the equations governing the interacting system of scalar, electromagnetic and gravitational fields have been obtained. As a particular case it is shown that the equations of motion admit a special kind of solutions with sharp boundary known as droplets. For these solutions, the physical fields vanish and the space-time is flat outside of the critical sphere or cylinder. Therefore, the mass and the electric charge of these configurations are zero.Comment: 17 pages, Submitted to the International Journal of Theoretical Physic

4-Allyl-3-(2-methyl-4-quinol­yl)-1H-1,2,4-triazole-5(4H)-thione

In the title compound, C15H14N4S, the quinoline and triazole rings form a dihedral angle of 41.48 (7)°. In the crystal, adjacent mol­ecules are linked by N—H⋯N hydrogen bonds, forming chains along [100]

Methyl 4-methyl-2-oxo-1,2,5,6-tetra­hydro-4H-pyrrolo[3,2,1-ij]quinoline-6-carboxyl­ate

In the title mol­ecule, C14H15NO3, the six-membered heterocyclic ring exhibits an envelope conformation. In the crystal, C—H⋯π inter­actions link the mol­ecules into centrosymmetric dimers, and weak inter­molecular C—H⋯O hydrogen bonds link these dimers into columns propagated along [100]

Finitely generated free Heyting algebras via Birkhoff duality and coalgebra

Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and thus the free algebras can be obtained by a direct limit process. Dually, the final coalgebras can be obtained by an inverse limit process. In order to explore the limits of this method we look at Heyting algebras which have mixed rank 0-1 axiomatizations. We will see that Heyting algebras are special in that they are almost rank 1 axiomatized and can be handled by a slight variant of the rank 1 coalgebraic methods

Development of the potato cryocollection preserved in the VIR cryobank

Background. The article presents the results of the studies carried out within the framework of a complex program for the long-term conservation of genotyped accessions of advanced potato cultivars in the cryobank of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR). These accessions are genetically identical to the nomenclature standards of the corresponding cultivars.Materials and methods. The research material included 24 accessions from the in vitro collection of VIR, corresponding to the nomenclature standards of Russian potato cultivars developed in different breeding centers of the Russian Federation. Cryopreservation was carried out using the droplet vitrification method, several stages of which were modified in the Department of Biotechnology of VIR.Results and discussion. The frequency of post-cryogenic regeneration for the analyzed 24 cultivars in control variants with short-term immersion of explants in liquid nitrogen varied from 20 to 47.3%, and in 9 accessions it exceeded 39% – the current level of reliable long-term preservation of samples in cryobanks. The data of the statistical analysis failed to reveal a significant effect of the genotype or the calendar dates of different experiment replications on the regeneration ability. These 24 accessions were added to the potato cryocollection stored in the VIR cryobank. An analysis of the composition and structure of VIR’s potato cryocollection, which currently includes 140 accessions, is presented

Professional Doctorates: International Experience and Russian Context

The diversification of forms and types of doctoral programs is currently a global trend. Universities across the globe offer programs that differ in the modes of training, characteristics of the target audience, and possible labor markets after graduation. In Russia, doctoral education exists in a unified format, focusing primarily on the academic labor market. Recently, there have been discussions about the need to expand the range of programs and the types of academic degrees in Russia. In this article, we present the analysis of professional doctoral programs: in response to what challenges and needs they appeared, how they are implemented, in what forms they exist. In addition, we consider the Russian experience of implementing professional doctoral programs; analyze the existing opportunities and barriers for their development. Based on the analysis, we came to a conclusion about the relevance of the professional doctoral programs’ development in Russia, the expediency of simplifying the conditions for their implementation and legitimizing special requirements for the design of dissertations with an applied orientation

Scalar field in cosmology: Potential for isotropization and inflation

The important role of scalar field in cosmology was noticed by a number of authors. Due to the fact that the scalar field possesses zero spin, it was basically considered in isotropic cosmological models. If considered in an anisotropic model, the linear scalar field does not lead to isotropization of expansion process. One needs to introduce scalar field with nonlinear potential for the isotropization process to take place. In this paper the general form of scalar field potentials leading to the asymptotic isotropization in case of Bianchi type-I cosmological model, and inflationary regime in case of isotropic space-time is obtained. In doing so we solved both direct and inverse problem, where by direct problem we mean to find metric functions and scalar field for the given potential, whereas, the inverse problem means to find the potential and scalar field for the given metric function. The scalar field potentials leading to the inflation and isotropization were found both for harmonic and proper synchronic time.Comment: 10 page