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

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

Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

No abstract available

In Situ Observations during Chemical Vapor Deposition of Hexagonal Boron Nitride on Polycrystalline Copper.

Using a combination of complementary in situ X-ray photoelectron spectroscopy and X-ray diffraction, we study the fundamental mechanisms underlying the chemical vapor deposition (CVD) of hexagonal boron nitride (h-BN) on polycrystalline Cu. The nucleation and growth of h-BN layers is found to occur isothermally, i.e., at constant elevated temperature, on the Cu surface during exposure to borazine. A Cu lattice expansion during borazine exposure and B precipitation from Cu upon cooling highlight that B is incorporated into the Cu bulk, i.e., that growth is not just surface-mediated. On this basis we suggest that B is taken up in the Cu catalyst while N is not (by relative amounts), indicating element-specific feeding mechanisms including the bulk of the catalyst. We further show that oxygen intercalation readily occurs under as-grown h-BN during ambient air exposure, as is common in further processing, and that this negatively affects the stability of h-BN on the catalyst. For extended air exposure Cu oxidation is observed, and upon re-heating in vacuum an oxygen-mediated disintegration of the h-BN film via volatile boron oxides occurs. Importantly, this disintegration is catalyst mediated, i.e., occurs at the catalyst/h-BN interface and depends on the level of oxygen fed to this interface. In turn, however, deliberate feeding of oxygen during h-BN deposition can positively affect control over film morphology. We discuss the implications of these observations in the context of corrosion protection and relate them to challenges in process integration and heterostructure CVD.P.R.K. acknowledges funding from the Cambridge Commonwealth Trust and the Lindemann Trust Fellowship. R.S.W. acknowledges a research fellowship from St. John’s College, Cambridge. S.H. acknowledges funding from ERC grant InsituNANO (no. 279342), EPSRC under grant GRAPHTED (project reference EP/K016636/1), Grant EP/H047565/1 and EU FP7 Work Programme under grant GRAFOL (project reference 285275). The European Synchrotron Radiation Facility (ESRF) is acknowledged for provision of synchrotron radiation and assistance in using beamline BM20/ROBL. We acknowledge Helmholtz-Zentrum-Berlin Electron storage ring BESSY II for synchrotron radiation at the ISISS beamline and continuous support of our experiments.This is the final version. It was first published by ACS at http://pubs.acs.org/doi/abs/10.1021/cm502603

Выбор оптимального объема хирургического лечения при аноректальной меланоме: ретроспективный анализ реестра Российского общества специалистов по колоректальному раку

Background. Anorectal melanoma is a rare malignancy without established standard treatment.Aim. To analyse the Russian Colorectal Cancer Society melanoma registry and to assess optimal surgery with regard to the extent of the disease.Materials and methods. A retrospective analysis of the Russian Colorectal Cancer Society registry was carried out during 2000–2020. Patients with cutaneous melanoma colonic metastases as well as patients with less than 6 months follow-up were excluded. Basic patient group characteristics, overall and disease-free survival (were analyzed depending on disease stage (by A. Stefanou) and surgery type.Results. 16 patients had stage I–IIA, 24 – stage IIB, 29 patients – stage III and 24 patients – stage IV disease. Wide local excision was performed in 15 (93.8 %) patients with stage I–IIA, 15 (62.5 %) patients with stage IIB, 2 (6.9 %) patients with stage III, and 8 (33.3 %) patients with stage IV disease. Abdomino-perineal excision (APE) was performed in 0 patients with stage I–IIA, 7 (29.2 %) patients with stage IIB, 22 (75.9 %) patients with stage III, and 7 (29.2 %) patients with stage IV disease. 2-year overall survival was 74.5 % in stage I–IIA, 49.4 % in stage IIB, 64.3 % in stage III, and 10.4 % in stage IV disease; 2-year disease-free survival was 67 %, 23,4 %, 34,1 % in stage I–IIA, IIB, III disease accordingly. Median overall survival was 17.8 months, 38.3 months and 27.9 months for non-surgical treatment, wide local excision and APR in non-metastatic patients accordingly. Median disease-free survival was 6.0 months, 14.1 months and 12.0 months for non-surgical treatment, wide local excision and APR in non-metastatic patients accordingly.Conclusions. APR should be considered in patients with stage IIB and stage III (by A. Stefanou) anorectal melanoma. Wide local excision is the preferred treatment in other patients.Введение. Аноректальная меланома – редкое злокачественное новообразование, для которого отсутствуют общепринятые стандарты лечения.Цель исследования – анализ данных реестра редких заболеваний Российского общества специалистов по колоректальному раку по аноректальной меланоме и оценка оптимальной тактики лечения при различной степени распространенности заболевания.Материалы и методы. Проведен ретроспективный анализ реестра аноректальных меланом Российского общества специалистов по колоректальному раку за 2000–2020 гг. Из анализа исключали пациентов с метастазами меланомы кожи в толстую кишку, пациентов, прослеженных <6 мес. Анализировали основные клинические характеристики, характер метастазирования при различных стадиях, общую и безрецидивную выживаемость в зависимости от стадии по A. Stefanou и вида хирургического лечения.Результаты. В исследуемой группе было 16 пациентов с I–IIA стадией, 24 пациента с IIB стадией, 29 пациентов с III стадией и 24 пациента с IV стадией. Трансанальное иссечение было выполнено 15 (93,8 %) пациентам с I–IIA стадией, 15 (62,5 %) пациентам с IIB стадией, 2 (6,9 %) пациентам с III стадией и 8 (33,3 %) пациентам с IV стадией. Брюшно-промежностная экстирпация (БПЭ) прямой кишки была выполнена 7 (29,2 %) пациентам с IIB стадией, 22 (75,9 %) пациентам с III стадией, 7 (29,2 %) пациентам с IV стадией и не была выполнена ни одному из пациентов с I–IIA стадией. Двухлетняя общая выживаемость составила 74,5; 49,4; 64,3 и 10,4 % при I–IIA, IIB, III и IV стадии соответственно, 2-летняя БРВ – 67,0; 23,4 и 34,1 % при I–IIA, IIB и III стадии соответственно. Медиана общей выживаемости при неметастатических случаях составила 17,8; 38,3 и 27,9 мес для нехирургического лечения, трансанального иссечения и БПЭ прямой кишки соответственно, медиана безрецидивной выживаемости – 6,0; 14,1 и 12,0 мес.Выводы. Выполнение БПЭ прямой кишки следует рассматривать у пациентов с IIB и III стадиями аноректальной меланомы по A. Stefanou. У остальных пациентов при технической возможности следует выполнять трансанальное иссечение

A cyclic universe with colour fields

The topology of the universe is discussed in relation to the singularity problem. We explore the possibility that the initial state of the universe might have had a structure with 3-Klein bottle topology, which would lead to a model of a nonsingular oscillating (cyclic) universe with a well-defined boundary condition. The same topology is assumed to be intrinsic to the nature of the hypothetical primitive constituents of matter (usually called preons) giving rise to the observed variety of elementary particles. Some phenomenological implications of this approach are also discussed.Comment: 21 pages, 9 figures; v.4: final versio

Remarkable convergent evolution in specialized parasitic Thecostraca (Crustacea)

<p>Abstract</p> <p>Background</p> <p>The Thecostraca are arguably the most morphologically and biologically variable group within the Crustacea, including both suspension feeders (Cirripedia: Thoracica and Acrothoracica) and parasitic forms (Cirripedia: Rhizocephala, Ascothoracida and Facetotecta). Similarities between the metamorphosis found in the Facetotecta and Rhizocephala suggests a common evolutionary origin, but until now no comprehensive study has looked at the basic evolution of these thecostracan groups.</p> <p>Results</p> <p>To this end, we collected DNA sequences from three nuclear genes [18S rRNA (2,305), 28S rRNA (2,402), Histone H3 (328)] and 41 larval characters in seven facetotectans, five ascothoracidans, three acrothoracicans, 25 rhizocephalans and 39 thoracicans (ingroup) and 12 Malacostraca and 10 Copepoda (outgroup). Maximum parsimony, maximum likelihood and Bayesian analyses showed the Facetotecta, Ascothoracida and Cirripedia each as monophyletic. The better resolved and highly supported DNA maximum likelihood and morphological-DNA Bayesian analysis trees depicted the main phylogenetic relationships within the Thecostraca as (Facetotecta, (Ascothoracida, (Acrothoracica, (Rhizocephala, Thoracica)))).</p> <p>Conclusion</p> <p>Our analyses indicate a convergent evolution of the very similar and highly reduced slug-shaped stages found during metamorphosis of both the Rhizocephala and the Facetotecta. This provides a remarkable case of convergent evolution and implies that the advanced endoparasitic mode of life known from the Rhizocephala and strongly indicated for the Facetotecta had no common origin. Future analyses are needed to determine whether the most recent common ancestor of the Thecostraca was free-living or some primitive form of ectoparasite.</p