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  • Author: Aleksandra Rutkowska x
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Portfolio optimization, one of the most rapidly growing field of modern finance, is selection process, by which investor chooses the proportion of different securities and other assets to held. This paper studies the influence of membership function’s shape on the result of fuzzy portfolio optimization and focused on portfolio selection problem based on credibility measure. Four different shapes of the membership function are examined in the context of the most popular optimization problems: mean-variance, mean-semivariance, entropy minimization, value-at-risk minimization. The analysis takes into account both: the study of necessary and sufficient conditions for the existence of extremes, as well as the statistical inference about the differences based on simulation.

Differences in semantic clustering and switching were examined in men with frontal lobe lesions, men with schizophrenia and healthy men. Men with frontal lobe lesions and men with schizophrenia generated fewer words than healthy men and presented intact clustering, but decreased switching during the semantic fluency task. However, after controlling for the number of words produced, between-group differences in switching disappeared. These findings suggest that all three groups used similar strategies of clustering and switching during the semantic fluency task, although men with frontal lobe lesions and men with schizophrenia did it less efficiently than healthy men.

Degradability of organic-inorganic cellulose acetate butyrate hybrids in sea water

Environmental degradability of novel organic-inorganic cellulose acetate butyrate hybrids obtained via solgel process was investigated. The degradation of hybrids was studied under marine exposure conditions in the Baltic Sea for a period of 25 weeks. The influence of characteristic parameters of sea water on the degree of degradation monitored by changes of weight and optical microscopy was discussed. The degraded samples were also examined by FT-IR spectroscopy. It has been established that the CAB/silica hybrids are more susceptible to biodegradation in sea water environment than pure cellulose acetate butyrate.


The aim of this study was to evaluate the influence of exercises on a stabilometric platform on the physical fitness and mobility of patients with lung cancer after thoracic surgery. The Experimental Group included 22, and the Control Group consisted of 21 patients. All included patients were enrolled after thoracic surgery due to lung cancer. The Experimental and Control Groups were enrolled in a 3-week in-hospital pulmonary rehabilitation program. The Experimental Group additionally performed daily 20-min training sessions on a stabilometric platform. Agility and flexibility were assessed with the Fullerton test before and after rehabilitation in both groups, and quality of life was assessed with the SF-36 questionnaire. Exercise performance stated as a distance in a 6 min walking test (6MWT) significantly improved in both groups with a medium effect size. The results of the Fullerton test indicated improvements in flexibility in both groups after the completion of the program without a significant difference between the groups and with a small effect size. In the Experimental Group, the best results were observed in the Arm curl (p = 0.0001), Chair stand (p = 0.04), Up and go (p = 0.001) and Chair sit and reach (p = 0.0001) tasks. No deterioration in the quality of life was observed in the Experimental or the Control Group after the completion of the program. Between-group analyses revealed significant differences in the Role-Physical (RP) (p = 0.020) and Mental-Health (MH) (p = 0.025) domains of the SF-36. The rehabilitation program with a stabilometric platform improved agility and flexibility of patients after thoracic surgery without an effect size or significant differences between the Experimental and Control Groups.