Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae

We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of superhump period are found to be composed of three distinct stages: early evolutionary stage with a longer superhump period, middle stage with systematically varying periods, final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods less than 0.08 d show positive period derivatives. Contrary to the earlier claim, we found no clear evidence for variation of period derivatives between superoutburst of the same object. We present an interpretation that the lengthening of the superhump period is a result of outward propagation of the eccentricity wave and is limited by the radius near the tidal truncation. We interpret that late stage superhumps are rejuvenized excitation of 3:1 resonance when the superhumps in the outer disk is effectively quenched. Many of WZ Sge-type dwarf novae showed long-enduring superhumps during the post-superoutburst stage having periods longer than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently, mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives and are excellent candidate for the systems around or after the period minimum of evolution of cataclysmic variables (abridged).Comment: 239 pages, 225 figures, PASJ accepte

Development of Expert Assessment Methods in Planning Energy Supply of Buildings with Renewable Energy Sources

The object of research is the process of expert evaluation in planning the energy supply of buildings using renewable energy sources. The conducted research is based on the application of system analysis methods to formalize the process of expert evaluation in the planning of an energy system with renewable energy sources. Here were used methods of expert evaluation of characteristics of qualitative criteria, methods of the theory of fuzzy sets and fuzzy logic for the formation of the value of criteria, and methods of estimating the reliability of the expert evaluation. Methods of structural analysis and functional modelling of information systems are used to build structural and functional models of the expert evaluation process. The issue of creating an appropriate information system for planning a power system with renewable energy sources is considered. One of the components of the information system is the unit for evaluating candidate experts. A six-level algorithm of the hierarchical structure of expert selection is proposed. As a result of the algorithm, an expert group is formed. This paper shows the process of narrowing the circle of experts from twenty to three candidates. The list of criteria influencing the choice of experts is formed: length of service, availability of the certificate, the efficiency of decision-making, education. The process of assessing the stability of experts' opinions is shown. It is proposed to use the method of processing the opinions of experts to find the value of the membership functions of qualitative criteria. As a result of the study, a group of three experts was formed, whose opinions are taken into account when choosing alternatives to the energy system. In accordance with the proposed information technology of energy supply planning of buildings using renewable energy sources, an information system in the form of a web-oriented application is proposed. A separate part of the information system is a subsystem for working with experts. The diagram of sequence of actions of the expert and the interface of work with system is developed. The use of the information system allowed to increase the efficiency of questionnaires of experts and decision-making on the choice of the optimal structure of the power system as a whole

Genetic diversity of Escherichia coli in gut microbiota of patients with Crohn’s disease discovered using metagenomic and genomic analyses

Abstract Background Crohn’s disease is associated with gut dysbiosis. Independent studies have shown an increase in the abundance of certain bacterial species, particularly Escherichia coli with the adherent-invasive pathotype, in the gut. The role of these species in this disease needs to be elucidated. Methods We performed a metagenomic study investigating the gut microbiota of patients with Crohn’s disease. A metagenomic reconstruction of the consensus genome content of the species was used to assess the genetic variability. Results The abnormal shifts in the microbial community structures in Crohn’s disease were heterogeneous among the patients. The metagenomic data suggested the existence of multiple E. coli strains within individual patients. We discovered that the genetic diversity of the species was high and that only a few samples manifested similarity to the adherent-invasive varieties. The other species demonstrated genetic diversity comparable to that observed in the healthy subjects. Our results were supported by a comparison of the sequenced genomes of isolates from the same microbiota samples and a meta-analysis of published gut metagenomes. Conclusions The genomic diversity of Crohn’s disease-associated E. coli within and among the patients paves the way towards an understanding of the microbial mechanisms underlying the onset and progression of the Crohn’s disease and the development of new strategies for the prevention and treatment of this disease