Evaluation of the weighted least squares method for the analysis of categorical data.

Hypotheses about the relationship among variables in a multiway contingency table may be tested by analysis of the probability distribution of observed frequencies or transformation of these frequencies. Two model-based approaches for the testing of structural hypotheses are the log-linear model, using iterative maximum-likelihood (ML) estimation procedures and the weighted least squares (WLS) linear model method of Grizzle, Starmer and Koch (GSK), a general noniterative procedure. Both methods asymptotically provide the same estimates and test statistics. This study compared the GSK and log-linear approaches for testing hypotheses in r x c contingency tables. Tables were simulated under various conditions of table, sample, row-, and column-effect sizes. Test statistics for row and column effects, and interaction were calculated using: (i) GSK linear model, untransformed proportion (p); (ii) GSK linear model, logarithm of the proportion (log p); (iii) GSK linear model, log-odds (log p/(1-p)); and (iv) log-linear model. Type I error rates were examined, and the relative power of the procedures was studied. The log-linear model yielded Type I error rates close to the expected values; all GSK models yielded error rates higher than expected, with smallest error rates associated with logarithmic transformations. Sample size and table size had no effect on Type I error rates. All GSK procedures were uniformly more powerful than the log-linear procedure. Differences were most noticeable with medium effect sizes and diminished as sample and effect sizes increased. There were no systematic differences due to table size. Findings from this study are pertinent to applied researchers who wish to test hypotheses other than those of independence with categorical data. Hypothesis testing and interpretation of results are straightforward with a model-based approach and are thus encouraged. The results indicate that GSK methods provide the most powerful tests. Since the GSK method is easily implemented and can be understood by researchers familiar with linear regression analysis, it is recommended that the GSK method be used to analyze categorical data

Haloaerosoltherapy and complex recovery treatment based on it as methods of physical rehabilitation for patients with chronic obstructive pulmonary disease

Rehabilitation programs for patients with COPD are based on physical exercises usage, but accounting low tolerance to physical activity, this is not always a real task. The aim is to study the effect of haloaerosoltherapy (HAT) and complex rehabilitation treatment based on it on functional recovery of COPD patients. Materials and methods: 133 patients with COPD (GOLD II-III) beyond acute period were examined. Bronchial obstruction, intensity of clinical manifestations, disturbances of cardiovascular system were investigated. The 6-minute walk test was conducted. Results: Before treatment, it has been shown that exercise tolerance significantly depended on severity of bronchial obstruction, intensity of clinical manifestations and degree of cardiovascular risk. Treatment was carried out according to three treatment complexes (TC). TC-1 was based on HAT usage with certain concentration and dispersion of aerosol, 18-20 seances per course. In TC-2, singlet oxygen therapy was included, in TC-3 mineral water was administered as drinking use and inhalation. After course of treatment, walking distance covered in 6 minutes has been increased in patients of all groups. When using complex treatment, these changes were more pronounced. Con-clusions: HAT with appropriate dispersion and concentration of haloaerosol promotes in-creasing tolerance to physical activity and may be used as a stage of physical rehabilitation with possible subsequent therapeutic physical exercises. Notably pronounced positive dy-namics of studied data was noted in COPD patients convalescents after COVID-19

Assessing and managing operational risk with a special emphasis on terrorism risk

The objective of this thesis is to consider different risk management issues in relation to operational risk with a special emphasis on terrorism risk. Our motivation to implement research in this particularly challenging area of risk management is due to the increasing magnitude of operational losses over the last decade and their negative effect on financial industry. This thesis contributes to the existing research on operational risk in several ways. First, our research suggests a model that addresses the issue of dependence between operational losses and how it can be accounted for in the value of capital charge for operational risk. Second, we provide a better understanding of the impact of a particular type of operational risk event, specifically of terrorist attacks . As evidenced by the 9/11 attacks, this risk can be catastrophic and can have negative consequences on the behavior of financial markets. We implement empirical analysis of the impact of terrorist attacks on stock, bond and commodity markets and suggest possible diversification strategies of terrorism risk. Finally, we contribute to the area of operational risk transfer, by developing a model for pricing of a multiple-event coupon paying CAT bond. The bond that we consider covers exposure to catastrophic risk such as natural and man-made disasters, including terrorist events

Indices of the Oxidant andAntioxidant System and Endogenous Intoxication in the Convalescents After Community-Acquired Pneumonia

The objective was to study the peculiarities of metabolic processes in the system of lipid peroxidation - antioxidant defense and the manifestations of endogenous intoxication in patients with community acquired pneumonia in the acute stage of the disease and after antibiotic therapy in their interrelation with bronchial obstruction.Materials and methods. 81 patients with non-severe community acquired pneumonia at the age of 21 to 65 years were examined on the 2nd day of the hospitalization and after completing antibiotic therapy. The levels of lipid peroxidation products, activity of the antioxidant defense and levels of middle-mass molecules in the blood were determined by conventional methods.Results. Excessive accumulation of mainly final lipid peroxidation products in combination with insufficient activation of antioxidant defense was observed in patients with community acquired pneumonia at the acute stage of the disease. It manifested in the decrease in activity of superoxide dismutase by 1.2 times and the activity of catalase by 1.6 times causing statistically significant increase (by 2.8 times) in the level of oxidative stress coefficient. The level of middle-mass molecules, the markers of endogenous intoxication, also significantly increased.In comparison with the acute stage, increase in the levels of primary and intermediate products of lipid peroxidation was observed after antibacterial therapy while maintaining the high levels of Schiff’s base and middle-mass molecules.Conclusions. The acute period of non-severe community-acquired pneumonia is characterized by imbalance in the oxidant and antioxidant system with the activation of lipid peroxidation processes mainly at the final stages of the reaction on the background of decreased activity of superoxide dismutase and catalase. It is associated with severe endogenous intoxication.The conventional therapy in case of the community-acquired pneumonia does not significantly influence the studied processes. Increase in the levels of the primary and intermediate products of the lipid peroxidation on the background of high level of Schiff’s base, preservation of low activity of superoxide dismutase and catalase were determined. Moreover, metabolic disorders were more significant in patients with symptoms of bronchial obstruction.