Statistička teorija uzročnosti u neprekidnom slučaju

Finding the cause or determining what is the cause and what is the consequence are probably one of the eldest problems of science. Philosophy from the beginning deals with these issues in the most general way, but other sciences also try to solve this kind of problems within their object of interest. Based on the results of Probability theory, Theory of random processes and Statistics, Statistical theory of causality originated as one of mathematical answers to the problem of determining causality in an arbitrary system. After the seminal papers of Granger (1969) and Sims (1972) many authors considered different types of stochastically defined causality. These researches mainly belong to predicting theory. Namely, the question of interest is: whether we can predict with the same accuracy in case of reduction of available information. At first, the researches were focused on discrete time stochastic processes (time series). However, as it is pointed out, there is a need for defining causality for continuous time stochastic processes, because many processes of interest have continuous time parameter. Namely, for financial time series is explained that even though the agents have only perceptions in discrete time, the underlying stochastic process of interest is in continuous time. Thus, the development of continuous time modeling in finance is important motivation for considering causality in continuous time. Also, the observed causality in a discrete time model may depend on the length of interval between each two successive samplings. Mykland (1986) and Florens and Fougères (1996) were the authors of first papers in which we can find definitions of causality in continuous time, given in terms of σ-algebras, i.e. natural filtrations of stochastic processes. Also, in Gill and Petrović (1987) and in Petrović (1996) definition of causality was given in continuous time, but in term of Hilbert spaces, i.e. L2-framework. Recently, there have been several papers which deal with these themes. The field of research in this dissertation is consideration of some causality concepts that are generalizations of Granger causality adopted for stochastic processes with continuous time. Also, same relationships of developed concept of causality and already existed related theories (adopted distributions) are considered. This dissertation, beside Preface and References with 86 items, consists of four chapters 1. Theory of random processes - basic notions; 2. Theory of causality - review of known results; 3. Generalization of Granger causality for stochastic processes with continuous time; 4. Causality and adopted distribution of stochastic processes. Chapter 1 is a brief overview of notions of theory of probability and stochastic processes that will be use later. Some known concepts of causality, both in discrete and in continuous case, are presented in Chapter 2. We followed the chronological development of the Statistical theory of causality, and special attention is given to the concepts that have contributed to our researches. Chapter 3 presents some generalizations of Granger causality adopted for stochastic processes with continuous time. Our original results, related to properties of developed concepts of causality, are given there. Specially we focused our attention to integration of stoping times into considered concept of causality, to invariance of causality under convergence and to relationship between causality and markovianity. Finally, in Chapter 4, we give connections between considered concept of causality and concept of adapted distribution of stochastic processes (specific concept of equivalence of stochastic processes), which introduced mathematicians from Model theory, Kiesler and Hoove

ENTREPRENEURIAL PEDAGOGY – ENTREPRENEURIAL KIDS

U Europskoj Uniji uvidjeli su kako je poticanje poduzetnosti, inovativnosti i kreativnosti cje¬lokupnog stanovništva ključni faktor povećanja gospodarske konkurentnosti s ostatkom svijeta. Ključni dio sveukupne strategije održivog rasta i razvoja Europske Unije nazvane „Europa 2020“, sadrži akcijski plan čiji cilj je oslobađanje poduzetničkog potencijala i ukla¬njanje postojećih prepreka razvoju poduzetništva i osnaživanje poduzetničke kulture Euro¬pe. Cjeloživotno učenje podrazumijeva unapređivanje znanja i vještine unutar naše osobne, društvene i poslovne perspektive. Poduzetništvo je jedna od ključnih kompetencija cjeloži¬votnog učenja koju je potrebno sustavno razvijati i kroz osnovnoškolski odgoj i obrazovanje. S obzirom da pedagogija kao znanost podrazumijeva skup znanja o metodama, sredstvima i principima odgoja i obrazovanja, ona treba uključiti poduzetnički aspekt pedagogije i de¬finira je, po mogućnosti, kao zasebnu disciplinu koja bi se bavila primjenom odgojno-obra¬zovnih metoda usmjerene razvijanju poduzetničkog duha od najranijeg uzrasta: „Poduzet¬nička pedagogija trebala bi biti znanstvena disciplina/grana unutar područja pedagogijske znanosti koja bi se bavila istraživanjem i implementacijom didaktičko-metodičkih modela u odgojno-obrazovne procese. Nacionalna strategija obrazovnog sustava Srbije prepoznala je poduzetništvo kao jednu od ključnih kompetencija cjeloživotnog učenja. Kroz različite projektne aktivnosti koje se odnose na razvoj vještina i unapređivanja znanja učenika pre¬poznat je značaj neophodne sustavne implementacije poduzetništva u školske programe na svim obrazovnim nivoima. Sustavno uključivanje poduzetničke kompetencije učenika osnovnih škola u školske kurikulume važan je faktor njegove implementacije. U Europskom projektu: „Poduzetnička pedagogija – poduzetna djeca” istražujemo mogući pristup k rea¬lizaciji ovog izazova.Encouraging entrepreneurship, innovation, and creativity of the entire population have come to be seen, in the European Union, as a key factor in boosting economic competi¬tiveness with the rest of the world. The key part of the overall strategy for sustainable growth and development of the European Union called ‘’Europe 2020’’, contains an action plan which aims to release the entrepreneurial potential and removal of existing obstac¬les to the development of the entrepreneurial culture in Europe. Lifelong learning implies improving the knowledge and skills within our personal, social, and business perspective. Entrepreneurship is one of the key competences of lifelong learning that needs to be sys¬tematically developed through primary school education. Given that pedagogy as a scien¬ce implies knowledge about methods, means, and principles of education and training, it should include the entrepreneurial aspect of pedagogy and defines it, preferably, as a separate discipline which would deal with the application of educational methods that aim to develop the entrepreneurial spirit from an early age: ‘’Entrepreneurial pedagogy should be a scientific discipline/branch within the field of pedagogical science which would research and implement didactic-methodical models into educational processes. National strategy of educational system in Serbia has recognized entrepreneurship as one of the key competences of lifelong learning. It has been recognized, through various project activities related to the development of skills and advancing knowledge of students, the importance of essential systematic implementation of entrepreneurship into curricula at all educatio¬nal levels. The systematic inclusion of entrepreneurial competence of elementary school students into school curricula is an essential factor of its implementation. In the European project ‘’Entrepreneurial pedagogy - entrepreneurial children’’ a possible approach towar¬ds the realization of this challenge is being researched

The use of nanoemulsion-based edible coatings to prolong the shelflife of cheese

In this work, the pectin/oregano oil nanoemulsion coatings were investigated, in order to prolong the shelf-life of cheese. The water vapor barrier, mechanical and antimicrobial activity of prepared nanoemulsion coatings were examined. In addition, the textural properties of uncoated and pectin/oregano oil coated cheeses were followed for 2 weeks. The results showed that obtained coatings possessed high antimicrobial activity toward E. coli, S. aureus and C. albicans and satisfied mechanical and water vapor barrier resistance. The coatings were also effective on reducing losses of weight and firmness of cheeses. Overall, antimicrobial nanoemulsion/edible films from renewable sources were successfully produced and showed high potential to be applicable in food industry to prolong the shelf-life of cheeses

Doppler ultrasound study of portal hemodynamics in patients with Gaucher disease

Gaucher disease is a lysosomal storage disorder caused by a deficiency of the enzyme glucocerebrosidase and characterized by the presence of pathological macrophages laden with glucosylceramide. Hepatosplenomegaly is a common manifestation of Gaucher disease, but symptomatic portal hypertension is rarely seen. The study included 20 untreated adult patients with Gaucher disease (non-neuronopathic type 1) diagnosed with the presence of Gaucher cells in the bone marrow, and 20 healthy subjects as controls. The examination of patients included color Doppler ultrasonography (pulsed Doppler mode), resistive index (RI) and Doppler perfusion index (DPI) using a Toshiba Xario ultrasound machine and a convex array probe PVT-375AX (1.9-6 MHz) with the objective of analyzing portal hemodynamics. Results showed that all patients had enlarged liver and spleen, and their average sizes were significantly larger than those in the healthy controls (liver: 17.04 vs.14.02 cm; spleen: 22.2 vs. 10.74 cm). DPI values were significantly different between patients and controls (0.15 vs. 0.21). Considering DPI <0.15 indicates arterial liver hypoperfusion and hypoxia, it can be concluded that a number of patients had a problem with liver oxygenation, which may be linked to the high angiotensin-converting enzyme (ACE) levels obtained in the patients (339.42 U/L), 10 times greater than in control subjects. Since ACE is a potent vasoconstrictor produced by spleen macrophages in Gaucher disease, we can suppose that elevated ACE is associated with effects on the blood vessels of the liver and spleen

Green Extraction Strategy Using Bio-Based Aqueous Biphasic Systems for Polyphenol Valorization from Grape By-Product

Polyphenols are natural compounds with enhanced antioxidant properties. They are present in relatively high concentrations in fruit/vegetable by-products. Therefore, there is a need for the development of efficient and cost-effective methods for the separation and purification of these valuable compounds. Traditional extraction with organic solvents needs to be switched to novel methods that are more efficient, with reduced extraction times and low consumption of organic solvents. Aiming at developing sustainable processes for the separation and purification of phenolic compounds, we used three model compounds, namely resveratrol, quercetin, and gallic acid, to investigate ionic liquid-based aqueous biphasic systems (IL-ABSs) formed by choliniumbased IL in combination with polypropylene glycol with a molecular mass of 400 g/mol (PPG400). The ABS composition in the two-phase region was selected according to a previously determined phase diagram. Extraction studies indicated the preferential partition of resveratrol and quercetin toward the hydrophobic PPG-rich phase that is mainly dominated by its hydrophobic nature and the strong salting-out effect of ILs. On the other hand, due to its considerably hydrophilic nature, gallic acid preferentially migrates toward the IL phase. The achieved results from grape stem extract demonstrated high extraction efficiencies of cholinium dihydrogen phosphate (~99% for resveratrol for the PPG phase and 78% for gallic acid for the IL phase), with considerable selectivity, demonstrating promising outcomes for potential applications

Binomial coefficients and their visualization

In this paper, the authors present some of the results achieved by mathematicians who belonged to different cultures and lived in different time periods, but were engaged in determining (formula for determining) binomial coefficients. Also, the authors present a geometric interpretation of the binomial coefficients of the binomial expansion , for and present an idea for the visualization of both binomial and polynomial coefficients that they plan to experimentally test in the upcoming period.Publishe

CHARACTERIZATION OF THE GOLD MERCAPTOTRIAZOLE COMPLEX USING THE TANDEM QUADRUPOLE MASS SPECTROMETRY (TQD)

This work is aimed to characterize the gold complexes using the electron spray ionization (ESI), and atmospheric solids analysis probe (ASAP), tandem quadrupole mass spectrometer (TQD). It is demonstrated here that the use of the ASAP is more suitable than the ESI for a rapid analysis of the gold coatings in the solid and liquid state. The mass spectra indicate that mercaptotriazole and glycine can coordinate with the gold ion and to build complexes such as [Au-2MT-Gly] and [Au-2MT-2Gly]

Developing Teaching Competencies for Implementing Blended Learning in Higher Education: Experiences of Faculty of Science, University of Kragujevac

Part of this work was supported by ERASMUS+ funds (Strengthening Teaching Competencies in Higher Education in Natural and Mathematical Sciences, grant contract 2018-2467/001-001).Publishe

MASS SPECTROMETRY FOR STRUCTURAL CHARACTERIZATION OF NON-CYANIDE GOLD COMPLEX

In this work, the possibilities of a mass spectrometry approach towards the characterizations of the electrolyte for decorative gold plating based on mercaptotriazole were studied. All mass spectra were obtained using laser desorption ionization (LDI) method on a commercial matrix assisted laser desorption ionization – time of flight (MALDI-TOF) mass spectrometer. The LDI MS spectra of chloroauric acid gave evidence of the presence of a variety of monomeric and polymeric complexes. LDI MS spectra of the electrolyte obtained from chloroauric acid, glycine and mercaptotriazole revealed existence of the ion at m/z 472 which indicated that the complex [Au(NH2CH2COOH)(C2H2N3S)2]- has been formed

The evaluation of the antioxidant potential during the oxidative polymerization of polyphenol compounds induced by laccase enzyme

The polymerization and crosslinking of various phenolic compounds induced by the laccase enzyme have been in recent years increasingly used in food industry, due to the emergence of products with improved properties, especially with increased antioxidant activity. In this regard, this study has explored the laccase-induced structural changes of two types of naturally occurring polyphenols, named gallic acid and epigallocatechin gallate, and their antioxidant activity. In the first part, the effect of the laccase of different origin - laccase of white rot fungi (Ganoderma spp.), previously grown on waste cereals and commercial laccase from Novozym® 51003, were investigated. Based on the results obtained after incubation (24 h, 50ºC), the sample containing a mixture of polyphenols, rather than individually, gave visible changes in the reading of the UV-Vis spectrum and increased antioxidant activity with small differences between commercial laccase and laccase of white rot fungi, which indicates that laccase obtained by growing fungi on waste cereals may be competitive for such a purpose. Moreover, the use of such an obtained laccase is more environmentally friendly and economically viable than use of commercial one. Further process optimization of polyphenols polymerization was performed within the method of multifactor statistical analysis (Design Expert), by using of commercial laccase, where by the effect of enzyme concentrations (0.1, 0.3 and 0.5 U/ml) and incubation time (4, 14 and 24 h) were monitored. The maximal antioxidant activity, measured by both DPPH (inhibition of 58.58% of radicals) and FRAP (176.57 mmol Fe2+/ml) was achieved by a sample containing a mixture of polyphenols and 0.3 U/ml laccase enzymes, after 14 h, at 50˚C. The results of this study revealed that careful optimization of process variables during polyphenols polymerization is extremely important for obtaining the product with desirable value added properties, which may be implemented in food and pharmaceutical industry