Speeding Strings

There is a class of single trace operators in ${\cal N}=4$ Yang-Mills theory which are related by the AdS/CFT correspondence to classical string solutions. Interesting examples of such solutions corresponding to periodic trajectories of the Neumann system were studied recently. In our paper we study a generalization of these solutions. We consider strings moving with large velocities. We show that the worldsheet of the fast moving string can be considered as a perturbation of the degenerate worldsheet, with the small parameter being the relativistic factor $\sqrt{1-v^2}$. The series expansion in this relativistic factor should correspond to the perturbative expansion in the dual Yang-Mills theory. The operators minimizing the anomalous dimension in the sector with given charges correspond to periodic trajectories in the mechanical system which is closely related to the product of two Neumann systems.Comment: v3: added a reference to the earlier wor

Entrepreneurship in national economics: significance and potential of development

The purpose of the study was to develop proposals for the use of two comprehensive indexes to assess the social significance and the existing potential for entrepreneurship development in different countries. The study used information provided in the report on the Global entrepreneurship monitoring project. At the same time, the opinions of residents of 48 countries for 2018 were considered. The first index included four indicators, and the second index included five indicators. Mathematical models were developed and the values of these two complex indexes were calculated. The average values of the indexes and their ranges of change for most countries are determined. Lists of countries with high and low index values are given. A comparative analysis of the values of complex indexes typical for Russia and other countries is presented. The results of research are new and original, have scientific and practical significance

Phase transitions and phase diagram of the ferroelectric perovskite NBT-BT by anelastic and dielectric measurements

The complex elastic compliance and dielectric susceptibility of (Na_{0.5}Bi_{0.5})_{1-x}Ba_{x}TiO_{3} (NBT-BT) have been measured in the composition range between pure NBT and the morphotropic phase boundary included, 0 <= x <= 0.08. The compliance of NBT presents sharp peaks at the rhombohedral/tetragonal and tetragonal/cubic transitions, allowing the determination of the tetragonal region of the phase diagram, up to now impossible due to the strong lattice disorder and small distortions and polarizations involved. In spite of ample evidence of disorder and structural heterogeneity, the R-T transition remains sharp up to x = 0.06, whereas the T-C transition merges into the diffuse and relaxor-like transition associated with broad maxima of the dielectric and elastic susceptibilities. An attempt is made at relating the different features in the anelastic and dielectric curves to different modes of octahedral rotations and polar cation shifts. The possibility is also considered that the cation displacements locally have monoclinic symmetry, as for PZT near the morphotropic phase boundary.Comment: 11 pages, 9 figures, submitted to Phys. Rev.

Technological Developments and the Role of L2 Motivation in University English Language Teaching Education

The 21st century is the era of technology and digitalization in teaching and learning dynamics., The present study explores the function of L2 motivation in university-based English language teaching (ELT) education. It also seeks to comprehend how technological developments are changing L2 motivation and examines teachers coping mechanisms in this changing educational environment. This study employs a qualitative research approach to explore the university teachers choices of technology instruments and pedagogical choices for enhancing students’ L2 motivation. Thus, the study uses semi-structured interviews to collect data from the 15 university teachers, (8 from Pakistan and 7 from Russia). Moreover, the secondary aim of the study is to comprehend the variables influencing L2 teacher motivation, and pedagogical approaches. This study adds to the body of information on language teaching by emphasizing the necessity for university teachers to adapt to changes in L2 motivation by utilizing technology, developing cutting-edge resources, and creating motivating learning settings

Understanding the Complexity of Motivational Orientations towards Learning English among Pakistani Female University Students

The present study goal is to investigate female university students’ motivation toward learning English as Second Language (ESL) studying at the University of Sindh, Pakistan. Two main objectives of the study were to evaluate the motivational orientation of the female learners in terms of integrativeness or instrumentality. Second, to study the factors that affect the learners motivation towards learning English. A mixed-method approach was employed with descriptive and inferential statistics were performed on the data to evaluate the data. A number of 158 female students from both the Science and Arts faculties at the English and Chemistry departments filled the structured questionnaire. Additionally, to gain a deeper understanding of the researched phenomenon, the semi-structured interviews were conducted with 20 students. The findings revealed a complex portrait of the target population, with the most prominent motivational factors being integrative motive, classroom environment, and instrumental motive. Besides, the influence of teachers was found to induce behavioral changes, while gender did not appear to significantly impact the learning process

On stress/strain state in a rotating disk

In the framework of mechanics of continuum bodies, the problem of stress/strain state in a high-speed rotating disk of constant thickness has been considered. The material of the disk is assumed to be homogeneous, elastic/perfectly-plastic. In the plastic zone, the stresses and plastic strains are related by some associated law similar to the one employed in deformation theory of plasticity. The general algorithm of the solution covers any smooth plasticity function. At some steps of the algorithm, it is possible to get analytical expressions, particularly, for the quadratic Mises yield criterion. For the given model, the notion of control parameters (external and internal) has been introduced. The allowable boundaries of external parameters have been defined as well. For some states of the disk, the coherent values of external parameters have been obtained. The results are represented graphically to show various states of the disk. The usage of piecewise plasticity functions has been briefly discussed. The results obtained can be used in preliminary engineering design and related numerical codes.info:eu-repo/semantics/publishedVersio

Рабочая смена: восполнит ли молодежь кадровый дефицит в промышленности и аграрно-промышленном комплексе?

Дефицит квалифицированных рабочих кадров остается острой проблемой со времен кризиса 2008—2009 гг. В статье обсуждаются результаты двух социологических исследований, проведенных в регионах России с отчетливой отраслевой специализацией и предусматривавших анкетный опрос учащихся учреждений профтехобразования, а также экспертные интервью с руководством предприятий, отраслевых ассоциаций, торгово-промышленных палат и руко-водителями учреждений профтехобразования. Собранный материал дает информацию о том, какой контингент и почему приходит учиться рабочим профессиям; каким видит молодежь свое трудоустройство по окончании обучения; почему предприятиям по-прежнему сложно восполнять кадровый дефицит; появилась ли у бизнеса возможность долгосрочно планировать свои кадровые потребности, а у системы профтехобразования — эффективно на них отвечать. Показано, что выбор рабочей профессии определяется надеждой на достойно оплачиваемую работу, возможностью в короткий срок получить профессию и легкостью поступления в образовательное учреждение. Больше половины учащихся согласны практически со всеми позитивными утверждениями относительно рабочих профессий, но в то же время две трети понимают, что они связаны с тяжелыми либо опасными условиями труда. Хотя по окончании производственной практики большинство респондентов убедились в верности выбора профессии, в цеха и на поля идут далеко не все, что связано с невысокой зарплатой молодых кадров и/ или местом локализации предприятия при наличии альтернативы в виде работы в торговле или сервисе. Короткий горизонт планирования и низкий уровень рентабельности не позволяют предприятиям просчитывать свои кадровые потребности и формировать кадровый резерв, что дезориентирует систему профобразования и консервирует дисбалансы на рынке труда. Улучшению ситуации, по мнению как молодежи, так и экспертов, способствовало бы проведение государством более последовательной и эффективной политики поддержки промышленности и аграрно-промышленном ком-плексе (АПК)

Structure of Erm-modified 70S ribosome reveals the mechanism of macrolide resistance

Many antibiotics inhibit bacterial growth by binding to the ribosome and interfering with protein biosynthesis. Macrolides represent one of the most successful classes of ribosome-targeting antibiotics. The main clinically relevant mechanism of resistance to macrolides is dimethylation of the 23S rRNA nucleotide A2058, located in the drug-binding site, a reaction catalyzed by Erm-type rRNA methyltransferases. Here, we present the crystal structure of the Erm-dimethylated 70S ribosome at 2.4 Å resolution, together with the structures of unmethylated 70S ribosome functional complexes alone or in combination with macrolides. Altogether, our structural data do not support previous models and, instead, suggest a principally new explanation of how A2058 dimethylation confers resistance to macrolides. Moreover, high-resolution structures of two macrolide antibiotics bound to the unmodified ribosome reveal a previously unknown role of the desosamine moiety in drug binding, laying a foundation for the rational knowledge-based design of macrolides that can overcome Erm-mediated resistance