Feynman Diagrams and Differential Equations

We review in a pedagogical way the method of differential equations for the evaluation of D-dimensionally regulated Feynman integrals. After dealing with the general features of the technique, we discuss its application in the context of one- and two-loop corrections to the photon propagator in QED, by computing the Vacuum Polarization tensor exactly in D. Finally, we treat two cases of less trivial differential equations, respectively associated to a two-loop three-point, and a four-loop two-point integral. These two examples are the playgrounds for showing more technical aspects about: Laurent expansion of the differential equations in D (around D=4); the choice of the boundary conditions; and the link among differential and difference equations for Feynman integrals.Comment: invited review article from Int. J. Mod. Phys.

Working Students: Educational Success and Subjective Well-being

Recently, there has been an increase in the number of students who combine study with work. This requires special attention of universities to such students and updates the study of educational success factors. The study is relevant as considers working students as subjects of learning and life, from the standpoint of personal and professional development experience acquired at the university, involvement in the educational process, satisfaction with learning, and well-being.The purpose of the empirical study is to identify the features of educational experience, subjective well-being and self-change potential among working students. The study involves 290 students of bachelor and specialist programs from five universities. The sample includes students who work for more than half a year (N=95), work from time to time (N=90) and study only (N=105). The results showed that the educational experience is most formed among those students who combine their studies with work in the specialty which is being received at the university. Long-term and occasionally working students differ from non-working students by a higher desire to participate in developmental activities, confidence in their ability to successfully solve the problems of learning and social interaction, self-directed learning skills, tendency to analyze and self-control their learning.Also, working students are superior to those who are just studying in the self-change potential and the subjective well-being level. It is concluded that the success and well-being of working students are largely determined by their resources of subjectness and aspiration for development. This allows them to function successfully, combining educational and labor activities as two areas of experience accumulation. Directions for improving university practice in terms of creating conditions for the educational success of working students are proposed

Исследования микроспоридий рода Nosema в Томской области (Сибирь): ко-инвазия широко распространена в пчелиных семьях

Microsporidian protozoans Nosema are gut parasites that infect European honeybees (Apis mellifera) worldwide. In the Tomsk region, two species of microsporidia were registered in honeybees (A. mellifera): N. apis and N. ceranae. During the last 6 years, an increase in infections by Nosema in honeybees has been detected in the Tomsk region, while cases of mass bee colony deaths were rare (in 2016, two cases of winter losses of bee colonies in the northern districts of the Tomsk region have been reported by beekeepers). The infestation of bee colonies and apiaries have changed from 0% in 2012 to about 80% in 2016-2017. In 2013-2014, 60.0% of all infected apiaries were infected only with N. apis. In 2015-2017, most of the infected apiaries (52.2%) were infected with both species of microsporidia. Despite the predominance of co-infection in honeybees, replacement of N. apis by N. ceranae is not observed

Original Russian Text © A

384 Copper(II) chloride complexes are used as precursors of catalysts for transformations of chlorinated hydrocarbons. Earlier it was shown The stability of a number of {Cu II R} complexes, such as [ Cu II RCl 3 ] 2-, where R = CH 3 or i -C 3 H 7 , was confirmed by quantum-chemical calculations with the unrestricted DFT method (exchange-correlation functional PBE

The semantic and etymological peculiarities of the verbs of blame

The article deals with the semantic analysis of the verbs of blame (brawl, castigate, condemn, curse, damn, lecture, rate, rebuke, reprehend, reprimand, reproach, reprobate, reprove, row, strafe, swear, trounce) in the perspective of semantics, as well as etymology. In accordance with the dominant cross-disciplinary approach to the linguistic research, the semantics of the verbs under study is analyzed in correlation with the relevant extra-linguistic data. It reveals the necessity of using some data of cognitive linguistics together with etymological methods of semantic analysi

Оценка устойчивости состояния мерзлоты на шельфе Восточной Арктики при экстремальном сценарии потепления в XXI в.

A state of permafrost in the Arctic is the key to understanding whether methane, stored in the permafrost related gas hydrate, can release into the atmosphere. The global warming can lead to destabilization of the submarine permafrost and, thus, cause the methane releasing into the water. The near-bottom water temperature plays a significant role in the current state of the submarine permafrost, because it specifies a depth of thawing of the permafrost. We have numerically simulated evolution of the submarine permafrost on the East Siberia Arctic shelf for the last glacial cycle. In order to estimate a possible state and stability of the submarine permafrost we did carry out a numerical run based on the ICMMG SB RAS the coupled ocean-ice and submarine permafrost model. For the atmosphere forcing, the GFDL CM3 coupled climate model output, simulated under the scenario RCP8.5, was used. The scenario RCP8.5 was used since it predicted the strongest warming by the end of the 21-st century. The GFDL СM3 model, predicting the most pronounced Arctic warming, was also used in order to put the tentative upper boundary on the submarine permafrost degradation in this century.The results obtained show that the offshore permafrost exists across the vast East Siberia shelf. This permafrost occurs continuously but its thickness changes. Thickness of the permafrost within the most part of the East Siberia shelf is estimated 470–590 m when the value of 60 W/m2 was used for the geothermal flux. Our results reveal a certain rising of the bottom layer temperature on the shelf and subsequent penetration of a heat flux into the sediments. However, our results show that even the extreme warming is not sufficient to destabilize the submarine permafrost on the shelf of both, the Laptev Sea and the East Siberian Sea. By the end of the 21st century, upper boundary of the permafrost deepens by value from 1 to 11 m only due to the thermal effects, and by 5–10 m in addition if we take into account the salinity of sediments. However, the depth of the permafrost upper boundary is still smaller than that of the hydrate stability zone. The thickness of the methane hydrate stability zone on the shelf is estimated 770–870 m. Moreover, upper boundary of this zone occurs at a depth of 120–220 m below the sea bottom, which makes the gas hydrates be isolated from the seabed surface by the permafrost layer. The submarine permafrost functions as an impermeable lid and prevents the methane from destroyed gas hydrates.Приведены результаты расчётов динамики субаквальной мерзлоты на шельфе морей Восточной Арктики до 2100  г. с учётом атмосферного воздействия, соответствующего наиболее экстремальному сценарию потепления RCP8.5. Получены пространственные изменения в состоянии подводной мерзлоты и выделены области шельфа, наиболее чувствительные к возможным климатическим изменениям. Понижение границы мёрзлых пород при заданном сценарном потеплении до конца XXI в. в зависимости от области шельфа может составить 1–11 м только в результате теплового воздействия и дополнительно 5–10 м за счёт учёта засоления порового пространства донных отложений. Расчётная мощность зоны стабильности газогидратов метана на шельфе составила около 770–870  м. При этом её верхняя граница находится на глубине 120–220  м ниже дна, что делает газогидратный слой изолированным от поверхности морского дна слоем мёрзлого грунта

Стратегия профессионального взаимодействия в подготовке специалистов библиотечно-информационной сферы

Training of library professionals in the circumstances of transforming modern society is examined. The reasons for deteriorating librarian image are discussed, along the ways to preserve and prospects for the profession. The resources for library profession and libraries modernization within the context of developing library higher school based on sciences convergence, interdisciplinarity and transdisciplinarity are specified. The relevance and prospects for library profession, social and economic efficiency of library activities are examined with consideration of triad functional relations between libraries — higher professional schools — science. The transition to the new educational paradigm in the library and information sphere is examined against the background of the developing library innovative activity and the National Project “The culture” (2019–2024). The focus is also made on educating bachelors and masters in the discipline “Library and information work” (federal education standard FGOS 3++). The project activities are seen as a means of sociocultural design with the library and information instruments. The professional interaction in education is developing within the subject scope reflection contradictions between the sociocultural paradigm of the higher education and the pragmatic intellectual labor market, and between the higher school’s assessment scale and the market.Рассмотрена проблема подготовки специалистов библиотек в условиях трансформации современного общества. Названы причины падения имиджа профессии библиотекаря, способы ее сохранения и перспективы развития. Раскрыты предпосылки модернизации библиотечной профессии и современной библиотеки в контексте развития библиотечной высшей школы на основе конвергенции наук, междисциплинарности и трансдисциплинарности. Проблемы востребованности и перспективности библиотечной профессии, социально-экономической эффективности библиотечной деятельности изучены с учетом функциональных связей триады «библиотека–вуз–наука». Переход к новой образовательной парадигме в библиотечно-информационной сфере рассмотрен на фоне развития инновационной деятельности библиотеки, реализации национального проекта «Культура» (2019–2024 гг.). Особое внимание в характеристике взаимодействия вуза и библиотеки уделено подготовке к проектной деятельности бакалавров и магистров по направлению «Библиотечно-информационная деятельность» (ФГОС 3++). Проектная деятельность раскрыта как инструмент социокультурного проектирования с помощью инновационных библиотечно-информационных средств. Подчеркнуто: стратегия профессионального взаимодействия в подготовке специалистов библиотечно-информационной сферы развивается в рамках проблемного поля, отражающего противоречия между социокультурной парадигмой высшего образования и прагматикой рынка интеллектуального труда, между шкалой оценок профессионального труда вузом и рынком

Threshold J/ψ−J/\psi- production in nucleon-nucleon collisions

We analyze $J/\psi-$ production in nucleon-nucleon collisions near threshold in the framework of a general model independent formalism, which can be applied to any reaction $N+N\to N+N+V^0$, where $V^0=\omega$, $\phi$, or $J/\psi$. Such reactions show large isotopic effects: a large difference for $pp$- and $pn$-collisions, which is due to the different spin structure of the corresponding matrix elements. The analysis of the spin structure and of the polarization observables is based on symmetry properties of the strong interaction. Using existing experimental data on the different decays of $J/\psi-$meson, we suggest a model for $N+N\to N+N+J/\psi$, based on $t-$channel $\eta+\pi$-exchanges. We predict polarization phenomena for the $n+p\to n+p+J/\psi$-reaction and the ratio of cross sections for $np$ and $pp$-collisions. For the processes $\eta(\pi)+N\to N+J/\psi$ we apply two different approaches: vector meson exchange and local four-particle interaction. In both cases we find larger $J/\psi$-production in $np$-collisions, with respect to $pp$-collisions.Comment: 17 pages, 6 figure

New Indicators of Myocardial Work in Healthy Individuals

Aim. To study in healthy individuals the gender and age characteristics of left ventricular (LV) myocardial work indicators, their correlations with global LV deformity indicators and echocardiographic parameters characterizing LV systolic and diastolic functions.Materials and methods. 70 Healthy individuals (n=70; 34 men and 36 women; aged 39.3±8.9 years) were included in the study. The echocardiographic examination determined the standard parameters and indicators of myocardial work: global work efficiency (GWE), global constructive work (GCW), global wasted work (GWW), global myocardial work index (GWI); as well as the myocardium deformation characteristics: global longitudinal deformation (GLS), global radial deformation (GRS) and global circular deformation (GCS). Spearman's correlation coefficient was used to investigate the relationship between parameters. A correlation was considered weak at r≤0.3, moderate at 0.3<r<0.7, and strong at r≥0.7.Results. The average value of global work efficiency (GWE) in men was 97% (96; 98), in women – 98% (97; 98). Global constructive work (GCW) in men was 2343.8±350.4 mm Hg%, in women – 2362.2±343.8 mm Hg%. The average value of global wasted work (GWW) in men was 46 mm Hg% (27; 75), in women – 44 mm Hg% (33; 55.5). The global myocardial work index (GWI) in men was 2069.9±356.4 mm Hg%, in women – 2055.7±339.9 mm Hg%. No significant differences were found in the comparative analysis of performance indicators. The analysis of correlations found that the myocardial work indicators didn't have significant correlations with age. Ejection fraction was moderately correlated with GWI (r=0.45) and GCW (r=0.49). Global longitudinal strain was strongly correlated with GWI (r=0.77) and GCW (r=0.77). Global radial strain correlated moderately directly with GWI (r=0.4) and GCW (r=0.4). Global circular strain was moderately correlated with GCW (r=0.35). A strong negative correlation was found between the GWE indicator and the post systolic contraction index (PSI) (r=-0.85). At the same time, PSI and GWW had a strong positive correlation (r=0.85).Conclusion. Indicators of LV myocardial work in healthy individuals do not have gender differences. The efficiency of the work of the myocardium depends primarily on the deformation of the LV, while the constructive work is determined by the volume characteristics. The wasted work indicator depends on the number of segments that peak in the post-systolic period