q-Karamatine funkcije i asimptotska svojstva rešenja nelinearnih q-diferencnih jednačina

The purpose of the doctoral dissertation is to determine the conditions for the existence and to examine in detail the asymptotic properties of solutions of the second order nonlinear q-difference equations, with an application of the theory of q-regular variation. The half-linear q-difference equation was analyzed in the framework of q-regular variation. Necessary and sufficient conditions for the existence of q-regularly varying solutions of the half-linear q- difference equation were obtained. Moreover, sufficient conditions for all eventually positive solutions to be q-regularly varying were examined. In cases where this is possible, the application of q-Karamata’s integration theorem and properties of q-regularly varying functions have been used to determine the precise asymptotic formula of different types of solutions, which accurately describes the behavior of these solutions in long time intervals, which is of special importance from the point of view of application. The obtained results in the q-calculus were compared with the known results in the continuous and the discrete case, but also, they were used to obtain new results in the discrete asymptotic theory. The sublinear second order q-difference equation of Emden-Fowler type was also analyzed in the framework of q-regularly varying functions. Assuming that the coefficients of this equation are q-regularly varying functions, necessary and sufficient conditions for the existence of strongly increasing and strongly decreasing solutions, as well as their asymptotic representations at infinity, have been determined. Moreover, it was shown that all q-regularly varying solutions of the same regularity index have the same asymptotic representation at infinity. The obtained results enabled the complete structure of the set of q-regularly varying solutions to be presented

Sintering of fly ash based composites with zeolite and bentonite addition for application in construction materials

Due to pozzolanic characteristics, fly ash is commonly used as a cement replacement in construction composites. Addition of natural clays with sorption ability (i.e. zeolite and bentonite) in to the fly ash based construction materials is of both scientific and industrial interest. Namely, due to the application of sorptive clay minerals, it is possible to immobilize toxic heavy metals from the composite structure. The thermal compatibility of fly ash and zeolite, as well as fly ash and bentonite, within the composite was observed during sintering procedure. The starting components were used in 1:1 ratio and they were applied without additional mechanical treatment. The used compaction pressure for the tablets was 2 t•cm-2. The sintering process was conducted at 1000ºC and 1200ºC for two hours in the air atmosphere. The mineralogical phase composition of the non-treated and sintered samples was analyzed using X-ray diffraction method. Scanning electron microscopy was applied in the analysis of the microstructure of starting and sintered samples. The thermal behavior was observed via DTA method. The influence of temperature on the properties of fly ash-zeolite and fly ash-bentonite composites was investigate

Education for democratic citizenship in Europe

U članku se analiziraju primeri dobre prakse u oblasti obrazovanja za demokratiju i građansko društvo (u tekstu: demokratsko građanstvo) u Evropi. Socijalni i politički život Evropljana je sve kompleksniji. Intenzivne političke promene formiraju specifične društvene okolnosti u kojima stari obrasci ponašanja više nisu adekvatni, pa je potrebno usvajati nova znanja kako bi se razumeli novi društveno-politički procesi i uzelo aktivno učešće u njima. Obrazovanje odraslih u ovom kontekstu dobija širi smisao i značenje. Javlja se potreba za novim područjima obrazovanja, poput obrazovanja za demokratsko građanstvo, koje ima za cilj da doprinese razvoju kritičkog mišljenja i građanske odgovornosti kod odraslih i da podstakne na participaciju u rešavanju problema u svom okruženju i šire.The article analyzes the examples of good practice in the field of education for democratic citizenship in Europe. The social and political life of Europeans is increasingly complex. Intensive political changes shape specific social circumstances and the old models of behavior are no longer adequate. Consequently, it is necessary to acquire new knowledge in order to understand new political processes and take active part in them. In this context, the adult education assumes broader sense and meaning. A need for new fields of education arises, such as education for democratic citizenship which has as its goal to contribute to developing of critical thinking and citizen responsibility among adults and to encourage them to participate in solving of the problems in their community and broader environment

HAAR WAVELET OPERATIONAL MATRIX BASED NUMERICAL INVERSION OF LAPLACE TRANSFORM FOR IRRATIONAL AND TRANSCENDENTAL TRANSFER FUNCTIONS

Irrational and transcendental functions can often be seen in signal processing or physical phenomena analysis as consequences of fractional-order and distributed-order models that result in fractional or partial differential equations. In cases when finding solution in analytical form tends to be difficult or impossible, numerical calculations such as Haar wavelet operational matrix method can be used.  Haar wavelet establishes a direct procedure for transfer function inversion using the wavelet operational matrix for orthogonal function set integration. In this paper an inverse Laplace transform of irrational and transcendental transfer functions using Haar wavelet operational matrix is proposed. Results for a number inverse Laplace transforms are numerically solved and compared with the analytical solutions and solutions provided by commonly used Invlap and NILT algorithms. This approach is useful when the original cannot be represented by an analytical formula and validity of the obtained result needs to be crosschecked and error estimated

Hranidbeno ponašanje pasa lutalica u javnom prihvatilištu

Feeding time of stray dogs on the first, second, third, fifth and seventh day of captivity in a municipal shelter was studied. The average value of the feeding time of dogs decreased from the first day (429.07±107.08 seconds) to the third day in captivity when it reached the lowest average value (229.53±95.18 seconds). The feeding time of dogs on the third day in captivity differs significantly from the same parameter on the first (429.07±107.08 seconds) and second day (372.73±100.58 seconds) in captivity (p lt 0.01). The highest average value of feeding time of stray dogs in the shelter was recorded on the first day. On the fifth and seventh day the feeding time of dogs increased compared to the third day. However, there were no significant differences of the average value of feeding time on the third day comparing with the fifth day (260.8±111.06 seconds) or the seventh day (301.33±119.89 seconds). Dogs ate their food more slowly on the fifth and the seventh day than on the third day, but more quickly than on the first and the second day (372.73±100.58 seconds). Significant differences were estimated comparing the feeding time of dogs on the first day with the third (p lt 0.01), fifth (p lt 0.01), and seventh day (p lt 0.05) of housing in the municipal shelter. Also, the feeding time of dogs on the second day differed significantly from the third (p lt 0.01) and the fifth day (p lt 0.05).U radu su prikazani rezultati proučavanja brzine unošenja hrane kod pasa lutalica u javnom prihvatilištu u Beogradu prvog, drugog, trećeg, petog i sedmog dana boravka. Prosečna brzina unošenja hrane je opadala počev od prvog dana (429,07±107,08 sekundi) do trećeg dana boravka pasa u zatočeništvu kada je ovaj pokazatelj dostigao najnižu vrednost (229,53±95,18 sec). Brzina unošenja hrane trećeg dana se statistički značajno razlikovala u poređenju sa prvim danom (429,07±107,08 sec) i drugim danom (372,73±100,58 sec) boravka pasa u prihvatilištu (p lt 0,01). Najveća prosečna vrednost brzine unošenja hrane zabeležena je prvog dana boravka u prihvatilištu. Petog i sedmog dana boravka u prihvatilištu brzina unošenja hrane se povećala u poređenju sa trećim danom. Međutim, nisu uočene statistički značajne razlike u poređenju brzine unošenja hrane između trećeg i petog (260,8±111,06 sec) i trećeg I sedmog dana (301,33±119,89 sec). Psi su mnogo sporije unosili hranu petog i sedmog dana nego trećeg dana, ali brže nego prvog i drugog dana boravka u prihvatilištu (372,73±100,58 seconds). Značajne razlike su utvrđene u brzini unošenja hrane između prvog i trećeg (p lt 0,01), petog (p lt 0,01), sedmog dana (p lt 0,05) boravka pasa u prihvatilištu. Takođe, brzina unošenja hrane se značajno razlikovala i drugog dana u poređenju sa trećim (p lt 0,01) i petim danom (p lt 0,05)

Numerical analysis of stress distribution in total hip replacement implant

Total hip replacement implants represent permanent implants and require large bone and cartilage removal during implantation. Revision would affect joint capability to sustain load, which makes this procedure irreversible. During exploitation, i.e. everyday activities, implants are subjected to dynamic loading. Thereby, these structures are prone to failure by fatigue. Highest stress states on total hip replacement implants are present in the neck area of the implant, which is a position of crack initiation. Under loading the implant neck exhibits tension and compression zones. Crack initiation in the neck side under tension would lead to crack opening and certain fracture. Implants are examined by experimental and numerical methods. The most common numerical method is finite element method (FEM) used to simulate different loading conditions. In this paper numerical analysis of stress distribution in the neck area is performed on a specific implant. Four numerical models are created in order to show how certain design solutions influence the stress distribution in the neck area

Numerical analysis of stress distribution in total hip replacement implant

Total hip replacement implants represent permanent implants and require large bone and cartilage removal during implantation. Revision would affect joint capability to sustain load, which makes this procedure irreversible. During exploitation, i.e. everyday activities, implants are subjected to dynamic loading. Thereby, these structures are prone to failure by fatigue. Highest stress states on total hip replacement implants are present in the neck area of the implant, which is a position of crack initiation. Under loading the implant neck exhibits tension and compression zones. Crack initiation in the neck side under tension would lead to crack opening and certain fracture. Implants are examined by experimental and numerical methods. The most common numerical method is finite element method (FEM) used to simulate different loading conditions. In this paper numerical analysis of stress distribution in the neck area is performed on a specific implant. Four numerical models are created in order to show how certain design solutions influence the stress distribution in the neck area

Potential genomic biomarkers of obesity and its comorbidities for phthalates and bisphenol A mixture: In silico toxicogenomic approach

This in silico toxicogenomic study aims to explore the relationship between phthalates and bisphenol A (BPA) co-exposure and obesity, as well as its comorbid conditions, in order to construct a possible set of genomic biomarkers. The Comparative Toxicogenomics Database (CTD; http://ctd.mdibl.org) was used as the main data mining tool, along with GeneMania (https://genemania.org), ToppGene Suite (https://toppgene.cchmc.org) and DisGeNET (http://www. disgenet.org). Among the phthalates, bis(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) were chosen as the most frequently curated phthalates in CTD, which also share similar mechanisms of toxicity. DEHP, DBP and BPA interacted with 84, 90 and 194 obesity-related genes/proteins, involved in 67, 65 and 116 pathways, respectively. Among these, 53 genes/proteins and 42 pathways were common to all three substances. 31 genes/proteins had matching interactions for all three investigated substances, while more than half of these genes/proteins (56.49%) were in co-expression. 7 of the common genes/proteins (6 relevant to humans: CCL2, IL6, LPL, PPARG, SERPINE1, and TNF) were identified in all the investigated obesity comorbidities, while PPARG and LPL were most closely linked to obesity. These genes/proteins could serve as a target for further in vitro and in vivo studies of molecular mechanisms of DEHP, DBP and BPA mixture obesogenic properties. Analysis reported here should be applicable to any mixture of environmental chemicals and any disease present in CTD

Značaj pojedinih nutrijenata u prevenciji i tretmanu hipertenzije

Oxidative stress, which develops due to imbalance of free radicals and antioxidant factors, has an important role in oxidative stress. The combination of different antioxidants can act sinergistically in the neutralization of free radicals, nitric oxide increase, improvement of vasodilatation and lowering blood pressure. This paper reviews the impact of certain food ingredients (vitamins, oligoelements, proteins) on prevention of hypertension and blood pressure lowering. Literature was found by searching the Medline database from 1995 to 2010 by using the following keywords: hypertension, prevention of hypertension, antioxidants, electrolytes, and nutrients. Excesive natrium intake as well as insufficiency of microelements in nutrition such as calcium, magnesium, zink and selenium contributes to the development of hypertension. A numerous nutritients used in prevention and treatment of hypertension (hydrolisates of soy proteins, whey, sardines, wheat germs, ω-3 and ω-6 unsaturated fatty acids, green and black tea, mushrooms, vitamin B6, L-arginine, flavonoids, taurine, allicin from garlic, active principles of hawtorn) have effects similar to certain groups of antihipertensive drugs (diuretics, beta blockers, calcium channel blockers, ACE inhibitors, angiotensin receptors blockers, central α-agonists, direct vasodilatators). Natural components are of importance in the prevention of hypertension but their potency is not sufficient to lower high blood pressure. However, certain individual components of natural food in combination with antihypertensive drugs may act synergistically, and with proper diet drug therapy can achieve a better effect.Hipertenzija je masovno oboljenje sa visokom stopom smrtnosti od komplikacija koje nastaju. Promena stila života, posebno načina ishrane ima značajnu ulogu u prevenciji nastanka hipertenzije i u odlaganju pojave komplikacija. Ovaj rad razmatra uticaj pojedinih sastojaka hrane (vitamina, oligoelemenata, proteina) na prevenciju i smanjenje povišenog krvnog pritiska. Literatura je pronađena pretraživanjem Medline baze u periodu od 1995. do 2010. godine korišćenjem sledećih ključnih reči: hipertenzija, prevencija hipertenzije, antioksidansi, elektroliti, nutrijenti. Razvoju hipertenzije doprinosi i prekomeran unos natrijuma, kao i nedostatak elektrolita i mikroelemenata u ishrani, kao što su: kalijum, magnezijum, kalcijum, cink i selen. Brojni nutrijenti koji se koriste u prevenciji i tretmanu hipertenzije (hidrolizati proteina soje, surutke, sardine i pšeničnih klica, ω-3 i ω-6 polinezasićene masne kiseline, zeleni i crni čaj, pečurke, vitamin B6, L-arginin, flavonoidi, taurin, alicin iz belog luka, aktivni sastojci gloga) imaju dejstvo slično pojedinim grupama antihipertenzivnih lekova (diuretici, β-blokatori, blokatori kalcijumskih kanala, ACE inhibitori i blokatori angiotenzinskih receptora, centralni α-agonisti, direktni vazodilatatori). Prirodne komponente su od značaja u prevenciji hipertenzije, ali njihova potentnost nije dovoljna da smanji povećani krvni pritisak. Međutim, pojedine prirodne komponente hrane u kombinaciji sa antihipertenzivnim lekovima mogu delovati sinergistički, te se uz odgovarajuću ishranu medikamentoznom terapijom može postići bolji efekat

Uticaj ponavljanog livenja na biokompatibilnost dentalnih legura zlata

Although highly noble Au alloys have been considered as biocompatible dental materials, little is known about whether recasting affects their biocompatibility. The aim of this work was to study the effect of repeated casting procedures on the microstructure and biocompatibilty of a noble Au dental alloy. The prepared samples of one- four- and eight times melted/cast Dentor S were used to study primary cutaneous irritation and sensibilization on experimental animals. The extract of the alloy prepared by conditioning the Dentor S samples in a cell culture medium was used to study the cytotoxicity on L929 cells. The elemental composition and surface changes of the alloy were examined by Energy Dispersive X-ray (EDX) analysis and optical microscopy, respectively. Our results showed that repeated casting decreased the biocompatibility of Dentor S, manifested as decreased metabolic and proliferative activities of L929 cells and that the effect correlated with the number of melting/casting procedures. However, neither sample of Dentor S caused irritation and sensibilization on experimental animals. EDX showed that recasting slightly increased the content of Au and Cu and slightly decreased the content of Pt, Pd and Zn. These changes correlated with the observations by optical microscopy. In conclusion, our results show that repeated casting of noble Au alloy changes its microstructure and decreases the biocompatibilty, suggesting that this procedure should be avoided in dental practice.Visoko plemenite legure su biokompatibilni materijali, ali je malo poznato da li ponovljena livenja legura utiču na njihovu biokompatibilnost. Cilj ovog rada je bio da se utvrdi efekat ponovljenog topljenja i livenja na mikrostrukturu i biokompatibilnost visoko plemenitih dentalnih legura zlata. Pripremjena je serija uzoraka od jednom, četiri i osam puta topljene i livene Dentor S legure za ispitivanje primarne iritacije kože i senzibilizacije na eksperimentalnim životinjama, kao i in vitro ispitivanje citotoksičnosti na L929 ćelijama. Hemijski sastav i promena površine legure ispitivana je EDX analizom i optičkim mikroskopom. Naši rezultati su ukazali da ponavljana livenja smanjuju biokompatibilnost Dentor S legure, koja se manifestuje smanjenjem metabolitičke i proliferativne aktivnosti L929 ćelija i da je efekat u korelaciji s brojem topljenja i livenja. Ni jedan uzorak Dentor S legure ne uzrokuje iritaciju i senzibilizaciju eksperimentalnih životinja. EDX analiza dokazuje da ponovna livenja blago povećavaju procenat Au i Cu i blago smanjuju procenat Pt, Pd i Zn. Ove promene su u korelaciji sa zapažanjima na optičkom mikroskopu. Autori zaključuju da ponovljena livenja visoko plemenitih legura zlata menjaju mikrostrukturu i smanjuju biokompatibilnost i preporučuju da se ova procedura izbegava u svakodnevnoj praksi