Computing the Rank Profile Matrix

The row (resp. column) rank profile of a matrix describes the staircase shape of its row (resp. column) echelon form. In an ISSAC'13 paper, we proposed a recursive Gaussian elimination that can compute simultaneously the row and column rank profiles of a matrix as well as those of all of its leading sub-matrices, in the same time as state of the art Gaussian elimination algorithms. Here we first study the conditions making a Gaus-sian elimination algorithm reveal this information. Therefore, we propose the definition of a new matrix invariant, the rank profile matrix, summarizing all information on the row and column rank profiles of all the leading sub-matrices. We also explore the conditions for a Gaussian elimination algorithm to compute all or part of this invariant, through the corresponding PLUQ decomposition. As a consequence, we show that the classical iterative CUP decomposition algorithm can actually be adapted to compute the rank profile matrix. Used, in a Crout variant, as a base-case to our ISSAC'13 implementation, it delivers a significant improvement in efficiency. Second, the row (resp. column) echelon form of a matrix are usually computed via different dedicated triangular decompositions. We show here that, from some PLUQ decompositions, it is possible to recover the row and column echelon forms of a matrix and of any of its leading sub-matrices thanks to an elementary post-processing algorithm

Scientific, institutional and personal rivalries among Soviet geographers in the late Stalin era

Scientific, institutional and personal rivalries between three key centres of geographical research and scholarship (the Academy of Sciences Institute of Geography and the Faculties of Geography at Moscow and Leningrad State Universities) are surveyed for the period from 1945 to the early 1950s. It is argued that the debates and rivalries between members of the three institutions appear to have been motivated by a variety of scientific, ideological, institutional and personal factors, but that genuine scientific disagreements were at least as important as political and ideological factors in influencing the course of the debates and in determining their final outcome

Solid 4He and the Supersolid Phase: from Theoretical Speculation to the Discovery of a New State of Matter? A Review of the Past and Present Status of Research

The possibility of a supersolid state of matter, i.e., a crystalline solid exhibiting superfluid properties, first appeared in theoretical studies about forty years ago. After a long period of little interest due to the lack of experimental evidence, it has attracted strong experimental and theoretical attention in the last few years since Kim and Chan (Penn State, USA) reported evidence for nonclassical rotational inertia effects, a typical signature of superfluidity, in samples of solid 4He. Since this "first observation", other experimental groups have observed such effects in the response to the rotation of samples of crystalline helium, and it has become clear that the response of the solid is extremely sensitive to growth conditions, annealing processes, and 3He impurities. A peak in the specific heat in the same range of temperatures has been reported as well as anomalies in the elastic behaviour of solid 4He with a strong resemblance to the phenomena revealed by torsional oscillator experiments. Very recently, the observation of unusual mass transport in hcp solid 4He has also been reported, suggesting superflow. From the theoretical point of view, powerful simulation methods have been used to study solid 4He, but the interpretation of the data is still rather difficult; dealing with the question of supersolidity means that one has to face not only the problem of the coexistence of quantum coherence phenomena and crystalline order, exploring the realm of spontaneous symmetry breaking and quantum field theory, but also the problem of the role of disorder, i.e., how defects, such as vacancies, impurities, dislocations, and grain boundaries, participate in the phase transition mechanism.Comment: Published on J. Phys. Soc. Jpn., Vol.77, No.11, p.11101

Optimizing multi-inserts in routing problems with constraints

We consider a problem of sequential traversal of megalopolises (nonempty finite sets) with travel cost functions depending on the set of pending tasks and precedence constraints. Its formulation is aimed at engineering problems in fission power generation connected with minimizing the exposure of staff to radiation and in machine engineering (routing of a CNC sheet cutting machine's tool). This discrete optimization problem is assumed to be sufficiently large-scale to necessitate the use of heuristics. We consider a procedure of local improvement for heuristics through a successive application of optimizing multi-inserts-finite disjoint sets of inserts. Each insert is assumed to be optimized by means of a broadly understood dynamic programming procedure. We show that in an "additive" routing problem of this kind (with precedence constraints and complex travel cost functions) the result's improvements are also aggregated additively. The proposed construction admits a parallel implementation for multiprocessor systems; in this case, the inserts are distributed to computational nodes and formed in an independent way. © 2018 Udmurt State University.All Rights Reserved.Funding. This work was supported by the Russian Science Foundation (project no. 14–11–00109)

Osobennosti zhirovogo obmena pri bolezniItsenko-Kushinga

The reported clinical case represents an example of characteristic traits in lipid metabolism and fat tissue deposition in hypercorticosolism. Probable causes for fat mass expansion in glucocorticosteroid excess, its distinctive cushingoid distribution, role of 11β-HSD1 and glucocorticoid receptors and reversibility of specific abnormalities after correction of hypercortisolism are discussed in the context of physiological and pathological aspects of glucocorticosteroid action.</jats:p

Резистентность к антибактериальным препаратам и бактериофагам изолятов Klebsiella pneumoniae, выделенных от детей разного возраста с кишечными инфекциями

The aim is to study the antibiotic and phage resistance of K. pneumoniae strains isolated from children with acute intestinal infections. Materials and methods. 490 K. pneumoniae strains isolated by the bacteriological method from feces from patients with intestinal infections of various etiologies aged from 1 month to 18 years in the period 2019—2021 were studied. The diagnosis of intestinal infection caused by K. pneumoniae was established taking into account the detection of the pathogen at a concentration of at least 5 lg CFU/g (n = 283; 57.8%). Children with Klebsiella seeding, made up three age groups: from 1 to 12 months of life (n = 245; 50%); from 1 to 3 years (n = 131; 26.7%); from 3 to 18 years (n = 114; 23.3%). Results. A higher frequency of K. pneumoniae seeding in high concentrations from fecal samples of children with intestinal infections aged from 1 to 12 months was established (?2 = 14.24; p &lt; 0.001). Analysis of the frequency of K. pneumoniae resistance to antimicrobials revealed its increase to ampicillin/sulbactam from 4.2 ± 1.6% to 9.7 ± 1.9% and to gentamicin from 3.0 ± 1.3% to 7.6 ± 1.7% (p &lt; 0.05) with an increase in the concentration of the pathogen from 3—4 to 5—6 lg CFU/ml. In K. pneumoniae strains isolated in low concentrations, resistance to polyvalent anti-klebsiella bacteriophage was significantly higher than to monovalent bacteriophage. Conclusion. Children of the first year of life belong to the risk group for the development of klebsiella intestinal infection. An increase in the frequency of K. pneumoniae resistance to ampicillin/sulbactam and gentamicin correlates with an increase in the concentration of the pathogen in fecal samples.Цель — совершенствование этиотропной терапии бактериальных ОКИ у детей различных возрастных групп на основе определения резистентности штаммов Klebsiella рneumoniae внебольничного происхождения к антибиотикам и бактериофагам. Материалы и методы. Исследованы 490 штаммов K. pneumoniae, выделенных бактериологическим методом из фекалий от больных кишечными инфекциями различной этиологии в возрасте от 1 месяца до 18 лет в период 2019—2021 гг. Диагноз кишечной инфекции, вызванной K. pneumoniae, устанавливали при обнаружении возбудителя в концентрации не менее 5 lg КОЕ/г (n = 283; 57,8%). Дети с высевом клебсиелл составили три возрастные группы: от 1 до 12 месяцев (n = 245; 50%); от 1 до 3 лет (n = 131; 26,7%); от 3 до 18 лет (n = 114; 23,3%). Результаты. Установлена более высокая частота высевов K. pneumoniae в высоких концентрациях из фекальных проб детей с кишечными инфекциями в возрасте от 1 до 12 месяцев (χ2 = 14,24; p &lt; 0,001). Анализ частоты резистентности K. pneumoniae к антимикробным препаратам выявил ее нарастание к ампициллину/сульбактаму с 4,2 ± 1,6% до 9,7 ± 1,9% и к гентамицину с 3,0 ± 1,3% до 7,6 ± 1,7% (p &lt; 0,05) с повышением концентрации возбудителя от 3—4 до 5—6 lg КОЕ/мл. У штаммов K. pneumoniae, выделенных в низкой концентрации, резистентность к поливалентному антиклебсиеллезному бактериофагу, была значимо выше, чем к моновалентному бактериофагу. Заключение. Дети первого года жизни относятся к группе риска по развитию клебсиеллезной кишечной инфекции. Нарастание частоты резистентности K. pneumoniae к ампициллину/сульбактаму и к гентамицину коррелирует с повышением концентрации возбудителя в пробах фекалий

Mobile communication and health of population: estimation of danger, social and ethical problems

Population lives under new electromagnetic conditions: constant round-the-clock compulsory chronic exposure of all groups of population to modulated wide spectrum of EMF RF during the work of base stations of mobile communication; daily and lifelong (from childhood) exposure of the brain to EMF RF of the mobile phone. Effects of exposure to EMF RF of low levels are presented. Results of research into chronic EMF RF exposure are absent. International recommendations and domestic guidelines do not take into account the changing conditions of EMF RF influence on the population: the brain has become a critical body, and children have been included in the risk group. Population actively continues to use mobile communication. In this situation estimation of the risks from mobile communication has become a social and ethical problem