Izbor atributa integracijom znanja o domenu primenom metoda odlučivanja kod prediktivnog modelovanja vremenskih serija nadgledanim mašinskim učenjem

The aim of the research presented within this doctoral dissertation is to develop a feature selection methodology through integrating domain-specific knowledge by applying mathematical methods of decision-making, to improve the feature selection process and the precision of supervised machine learning methods for predictive modeling of time series. To integrate domain-specific knowledge, a multi-criteria decision making method is used, i.e. an analytical hierarchical process proven to be successful in numerous studies carried out to date. This approach was selected because it allows the selection of a set of factors based on their relevance, even in the case of mutually opposite criteria. In predicting the movement of time series, the possibility of integrating feature relevance into support vector machines to improve their prediction accuracy was studied. The proposed methodology was applied as a feature-selection method for the predictive modelling of movement of financial time series. Unlike existing approaches, where the feature selection method is based on a quantitative analysis of the input values, the proposed methodology carries out a qualitative evaluation of the attributes in relation to the prediction domain and represents a means of integrating a priori knowledge of the prediction domain

Izbor atributa integracijom znanja o domenu primenom metoda odlučivanja kod prediktivnog modelovanja vremenskih serija nadgledanim mašinskim učenjem

The aim of the research presented within this doctoral dissertation is to develop a feature selection methodology through integrating domain-specific knowledge by applying mathematical methods of decision-making, to improve the feature selection process and the precision of supervised machine learning methods for predictive modeling of time series. To integrate domain-specific knowledge, a multi-criteria decision making method is used, i.e. an analytical hierarchical process proven to be successful in numerous studies carried out to date. This approach was selected because it allows the selection of a set of factors based on their relevance, even in the case of mutually opposite criteria. In predicting the movement of time series, the possibility of integrating feature relevance into support vector machines to improve their prediction accuracy was studied. The proposed methodology was applied as a feature-selection method for the predictive modelling of movement of financial time series. Unlike existing approaches, where the feature selection method is based on a quantitative analysis of the input values, the proposed methodology carries out a qualitative evaluation of the attributes in relation to the prediction domain and represents a means of integrating a priori knowledge of the prediction domain

Analysis of factors influencing Cu(II) sorption by clinoptiolite

The effects of initial metal concentration and pH, as well as the sorbent mass and particle size, on Cu(II) sorption by natural clinoptilolite were evaluated and compared. Full factorial experimental design at two levels was applied. Statistically significant factors were determined considering residual Cu(II) concentrations as a system response.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

STOCK MARKET TREND PREDICTION USING SUPPORT VECTOR MACHINES

The aim of the paper was to outline a trend prediction model for the BELEX15 stock market index of the Belgrade stock exchange based on Support Vector Machines (SVMs). The feature selection was carried out through the analysis of technical and macroeconomics indicators. In addition, the SVM method was compared with a "similar" one, the least squares support vector machines - LS-SVMs to analyze their classification precisions and complexity. The test results indicate that the SVMs outperform benchmarking models and are suitable for short-term stock market trend predictions

Effects of cisplatin on lipid peroxidation and the glutathione redox status in the liver of male rats: The protective role of selenium

The role of oxidative stress in cisplatin (CP) toxicity and its prevention by pretreatment with selenium (Se) was investigated. Male Wistar albino rats were injected with a single dose of cisplatin (7.5 mg CP/kg b.m., i.p.) and selenium (6 mg Se/kg b.m, as Na2SeO3, i.p.) alone or in combination. The results suggest that CP intoxication induces oxidative stress and alters the glutathione redox status: reduced glutathione (GSH), oxidized glutathione (GSSG) and the GSH/GSSG ratio (GSH RI), resulting in increased lipid peroxidation (LPO) in rat liver. The pretreatment with selenium prior to CP treatment showed a protective effect against the toxic influence of CP on peroxidation of the membrane lipids and an altering of the glutathione redox status in the liver of rats. From our results we conclude that selenium functions as a potent antioxidant and suggest that it can control CP-induced hepatotoxicity in rats

Immobilization of Co-60 and Sr-90 Ions Using Red Mud from Aluminum Industry

The removal of Co-60 and Sr-90 from the aqueous phase was tested using red mud - the fine grained residue from bauxite ore processing. This industrial waste represents a mixture of numerous minerals, mainly oxides and hydroxides of Fe, Al, Si, and Ti. Experiments were conducted as a function of contact time, pH, and pollutant concentrations. Kinetic data were well fitted with a pseudo-second order equation. The calculated rate constants and initial sorption rates indicated faster sorption of Sr2+ ions. Removal of both cations rapidly increased with the initial pH increase from 2.5 to 3.5. With the further increase of pH, Co2+ sorption was nearly constant (98%-100%), whereas Sr2+ removal remained at the same level to initial pH similar to 8 and gradually increased to 100% at pH 12. Equilibrium sorption data followed the Langmuir model, with the maximum sorption capacities of 0.52 mmol/g for Co2+ and 0.31 mmol/g for Sr2+. Sorbed cations exhibited high stability in distilled water. Desorption of Co2+ was also negligible in the presence of the competing Ca2+ cation, while 42%-25% of Sr2+ ions were desorbed depending on the previously sorbed amount. The results indicate that red mud is of potential significance as Co2+ and Sr2+ immobilization agent due to its high efficiency, abundance, and low-cost

Health-related quality of life in elderly patients hospitalized with chronic heart failure

Background: Chronic heart failure is a very common condition in the elderly, characterized not only by high mortality rates, but also by a strong impact on health-related quality of life (HRQOL). Previous studies of HRQOL in elderly heart failure subjects have included mostly outpatients, and little is known about determinants of HRQOL in hospitalized elderly population, especially in Serbia. In this study, we tried to identify factors that influence HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Methods: The study population consisted of 136 patients aged 65 years or older hospitalized for chronic heart failure. HRQOL was assessed using the Minnesota Living with Heart Failure questionnaire. Predictors of HRQOL were identified by multiple linear regression analysis. Results: Univariate analysis showed that patients with lower income, a longer history of chronic heart failure, and longer length of hospital stay, as well as those receiving aldosterone antagonists and digoxin, taking multiple medications, in a higher NYHA class, and showing signs of depression and cognitive impairment had significantly worse HRQOL. Presence of depressive symptoms (P lt 0.001), higher NYHA class (P=0.021), lower income (P=0.029), and longer duration of heart failure (P=0.049) were independent predictors of poor HRQOL. Conclusion: Depressive symptoms, higher NYHA class, lower income, and longer duration of chronic heart failure are independent predictors of poor HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Further, there is an association between multiple medication usage and poor HRQOL, as well as a negative impact of cognitive impairment on HRQOL. Hence, measures should be implemented to identify such patients, especially those with depressive symptoms, and appropriate interventions undertaken in order to improve their HRQOL

The first isolation and molecular characterization of Toxoplasma gondii from horses in Serbia

Background: Consumption of undercooked or insufficiently cured meat is a major risk factor for human infection with Toxoplasma gondii. Although horsemeat is typically consumed rare or undercooked, information on the risk of T. gondii from infected horse meat to humans is scarce. Here, we present the results of a study to determine the presence of T. gondii infection in slaughter horses in Serbia, and to attempt to isolate viable parasites. Methods: The study included horses from all regions of Serbia slaughtered at two abattoirs between June 2013 and June 2015. Blood sera were tested for the presence of specific IgG T. gondii antibodies by the modified agglutination test (MAT), and samples of trypsin-digested heart tissue were bioassayed in mice. Cyst-positive mouse brain homogenates were subjected to DNA extraction and T. gondii strains were genotyped using 15 microsatellite markers (MS). Results: A total of 105 slaughter horses were sampled. At the 1: 6 cut-off 48.6% of the examined horses were seropositive, with the highest titre being 1: 400. Viable parasites were isolated from two grade type mares; both parasite isolates (RS-Eq39 and RS-Eq40) were T. gondii type III, and both displayed an increased lethality for mice with successive passages. These are the first cases of isolation of T. gondii from horses in Serbia. When compared with a worldwide collection of 61 type III and type III-like strains, isolate RS-Eq39 showed a combination of MS lengths similar to a strain isolated from a duck in Iran, and isolate RS-Eq40 was identical in all markers to three strains isolated from a goat from Gabon, a sheep from France and a pig from Portugal. Interestingly, the source horses were one seronegative and one weakly seropositive. Conclusions: The isolation of viable T. gondii parasites from slaughter horses points to horsemeat as a potential source of human infection, but the fact that viable parasites were isolated from horses with only a serological trace of T. gondii infection presents further evidence that serology may not be adequate to assess the risk of toxoplasmosis from horsemeat consumption. Presence of T. gondii type III in Serbia sheds more light into the potential origin of this archetypal lineage in Europe

Immobilization of 60Co and 90Sr ions using red mud from aluminum industry

The removal of 60Co and 90Sr from the aqueous phase was tested using red mud - the fine grained residue from bauxite ore processing. This industrial waste represents a mixture of numerous minerals, mainly oxides and hydroxides of Fe, Al, Si, and Ti. Experiments were conducted as a function of contact time, pH, and pollutant concentrations. Kinetic data were well fitted with a pseudo-second order equation. The calculated rate constants and initial sorption rates indicated faster sorption of Sr2+ ions. Removal of both cations rapidly increased with the initial pH increase from 2.5 to 3.5. With the further increase of pH, Co2+ sorption was nearly constant (98%-100%), whereas Sr2+ removal remained at the same level to initial pH ~8 and gradually increased to 100% at pH 12. Equilibrium sorption data followed the Langmuir model, with the maximum sorption capacities of 0.52 mmol/g for Co2+ and 0.31 mmol/g for Sr2+. Sorbed cations exhibited high stability in distilled water. Desorption of Co2+ was also negligible in the presence of the competing Ca2+ cation, while 42%-25% of Sr2+ ions were desorbed depending on the previously sorbed amount. The results indicate that red mud is of potential significance as Co2+ and Sr2+ immobilization agent due to its high efficiency, abundance, and low-cost. [Projekat Ministarstva nauke Republike Srbije, br. 43009

Sorption and mobility of Co(II) in relation to soil properties

The kinetic and equilibrium sorption data of Co(II) ions were obtained from batch sorption experiments, using soils samples with a wide range of texture, carbonate and organic content. Sequential extraction protocol was applied to evaluate Co(II) interactions with soil fractions. The parameters, obtained from kinetic and isotherm data modeling, as well as the results of Co(II) distribution and desorption studies, were correlated with soil properties. Kinetics of Co(II) sorption was fast and obeyed the pseudo-second order kinetic model at the contact time ranged from 30 min to 30 days, using Co(II) concentration of 1.5 x 10(-3) mol L-1. Maximum sorption capacities were highly correlated with soil pH. The sorbed Co(II) was associated with Fe,Mn-oxide and carbonate phase of calcareous soil, whereas in other soil types ion-exchangeable fraction was dominant. The effect of aging on Co (II) stabilization in soil was more pronounced for lower contamination levels and soils with higher pH. For non calcareous soils, the desorption of Co(II) could be achieved by EDTA and HCI solutions. (C) 2017 Elsevier B.V. All rights reserved