Evaluation of the Accident Rate of a Plant Equipped with an Aging Single Protective Channel by the Method of Supplementary Variables

This work calculates the reliability of protective systems of industrial facilities, such as nuclear, to analyze the case of equipment subject to aging, important in the extension of the qualified life of the facilities. By means of the method of supplementary variables, a system of partial and ordinary integral-differential equations was developed for the probabilities of a protective system of an aging channel. The system of equations was solved by finite differences. The method was validated by comparison with channel results with exponential failure times. The method of supplementary variables exhibits reasonable results for values of reliability attributes typical of industrial facilities.

Multiple correspondence analysis as a tool in sociological research

Multiple correspondence analysis is a form of a factorial multivariate data analysis which helps us summarize a large quantity of information with assistance of modern statistical programs. In this way, sociological correlations - which are then visually represented on a two-dimensional graph - are established between a certain number of active and supplementary variables, i.e. between the positions, dispositions and position-takings (French: prises de position) by the analyzed agents. It is a research tool initially introduced by a statistician Jean- Paul Benz?cri in the humanities and social sciences in the 1960s. Since the early 1970s, thanks to Pierre Burdieu, this methodological procedure has become an indispensable instrument in the empirical studies of sociologists who were familiar with structuralist approach in sociology. This paper consists of two main sections. The first one sets out the basic theoretical assumptions and methodological properties of multiple correspondence analysis. The aim of the second section is to give a brief recital of one particular research - i.e. its features and results - in order to get the interested sociological public aquaitned with it?s practicle potentials of this tool.

Bodies need yoga? No plastic surgery! Naturalistic versus instrumental bodies among professions in the Danish healthcare field

What characterises the similarities and differences in body investments among professions in the Danish healthcare field? This can be important when healthcare professionals relate to each other and to bodies of patients regarding differences in class, gender, age, and disease group. The study takes inspiration from Bourdieu’s sociology and the concept of health capital. We ask whether health capital can explain distinctions in the empirical data? We used the explorative–descriptive method multicorrespondence analysis (MCA) on data from 440 respondents gathered through an online survey. The respondents range from chief physicians to healthcare students. MCA makes it possible to condense frequency statistics and examine patterns of body investments through an examination of variables such as food intake, exercise, and medicine use that are then further related to supplementary variables such as social class and age. The analysis supports the concept of health capital and shows that some groups in the Danish healthcare field have a more instrumental body perception, such as the young age group (e.g. open to surgery, consume medicine, high exercise), while the upper-middle-class and older respondents have a more naturalistic perception of the body (e.g. read often, eat vegetables, practice yoga).

An alternative transient solution for semi-Markov queuing systems

By using a purely probabilistic argumentation, two theorems are proved. They simplify the existing methods of analysis for the {M/G/1} queuing system by means of the supplementary variables method.

Applications of Stochastic Semigroups to Queueing Models

Non-markovian queueing systems can be extended to piecewise-deterministic Markov processes by appending supplementary variables to the system. Then their analysis leads to an infinite system of partial differential equations with an infinite number of variables and non-local boundary conditions. We show how one can study such systems by using the theory of stochastic semigroups.

Modeling the Prediction of the Session Rating of Perceived Exertion in Soccer: Unraveling the Puzzle of Predictive Indicators

Purpose: To predict the session rating of perceived exertion (sRPE) in soccer and determine its main predictive indicators. Methods: A total of 70 external-load indicators (ELIs), internal-load indicators, individual characteristics, and supplementary variables were used to build a predictive model. Results: The analysis using gradient-boosting machines showed a mean absolute error of 0.67 (0.09) arbitrary units (AU) and a root-mean-square error of 0.93 (0.16) AU. ELIs were found to be the strongest predictors of the sRPE, accounting for 61.5% of the total normalized importance (NI), with total distance as the strongest predictor. The included internal-load indicators and individual characteristics accounted only for 1.0% and 4.5%, respectively, of the total NI. Predictive accuracy improved when including supplementary variables such as group-based sRPE predictions (10.5% of NI), individual deviation variables (5.8% of NI), and individual player markers (17.0% of NI). Conclusions: The results showed that the sRPE can be predicted quite accurately using only a relatively limited number of training observations. ELIs are the strongest predictors of the sRPE. However, it is useful to include a broad range of variables other than ELIs, because the accumulated importance of these variables accounts for a reasonable component of the total NI. Applications resulting from predictive modeling of the sRPE can help coaching staff plan, monitor, and evaluate both the external and internal training load.

The Genus Woronichinia (Cyanobacteria) in Natural Lakes of Drawa National Park (Poland)

Woronichinia Elenkin is a cyanobacteria genus characteristic of lentic ecosystems. The type species, W. naegeliana (Unger) Elenkin, often blooms in the plankton of eutrophic reservoirs but this genus also contains species sensitive to high nutrient concentrations. The study analyzed the diversity and biomass of Woronichinia in lakes in a national park, isolated from the direct impact of human activity. The lakes were in various trophic states resulting from gradual and natural changes of trophy. Trophy was assessed with the use of the trophic diatom index, according to the classification we proposed for natural lakes. The relationship between the biomass and the trophic state of lakes was investigated with the use of multivariate unconstrained analysis with supplementary variables. Five species of Woronichinia were identified in all trophic types of lakes except for two oligotrophic ones: W. compacta (Lemmerm.) Komárek & Hindák, W. delicatula (Skuja) Komárek & Hindák, W. karelica Komárek & Komárk.-Legn., W. obtusa Joosten and W. naegeliana (Unger) Elenkin. The occurrence and biomass of the species were related to the trophic state of the lakes. The absence of Woronichinia in two oligotrophic lakes could be due to the high concentration of humic compounds in the sediments. The low nitrogen-to-phosphorus ratio characteristic of the oligo-mesotrophic lakes resulted in increased species diversity. The lakes’ isolation from human activity fostered the development of rare and sensitive species such as W. delicatula and W. karelica.