Aritmetičke funkcije teorije brojeva

U ovom radu opisujemo aritmetičke funkcije teorije brojeva. Rad je podijeljen na četiri poglavlja. U prvom poglavlju donosimo definicije i pregled multiplikativnih funkcija, te aditivnih funkcija uz neka njihova svojstva. Funkcije koje obrađujemo su: Eulerova funkcija, zbroj djelitelja, broj djelitelja, Liouvilleova funkcija, Möbiusova funkcija, broj različitih prostih faktora, von Mangoldtova funkcija. U drugom poglavlju donosimo definiciju i tvrdnje vezane za Dirichletov produkt aritmetičkih funkcija, dok se u trećem poglavlju bavimo generalizacijom konvolucije. U posljednjem poglavlju definiramo derivaciju aritmetičke funkcije te opisujemo njezina svojstava i dokazujemo Selbergov identitet.In this thesis, we describe some arithmetic functions of the theory of numbers. Thesis is divided into four chapters. In the first chapter, we provide basic definitions and properties of multiplicative functions and additive functions. We also describe particular functions such as: Euler function, sum of divisor function, divisor function, Liouville function, Möbius function, the number of distinct prime factors and the von Mangoldt function. In the second chapter, we provide an overview of basic definition and claims related to the Dirichlet product of arithmetic functions, while in the third chapter we define the generalized convolutions. In the last chapter, we define the derivation of arithmetic functions, describe its properties, and prove the Selberg identity

Aritmetičke funkcije teorije brojeva

U ovom radu opisujemo aritmetičke funkcije teorije brojeva. Rad je podijeljen na četiri poglavlja. U prvom poglavlju donosimo definicije i pregled multiplikativnih funkcija, te aditivnih funkcija uz neka njihova svojstva. Funkcije koje obrađujemo su: Eulerova funkcija, zbroj djelitelja, broj djelitelja, Liouvilleova funkcija, Möbiusova funkcija, broj različitih prostih faktora, von Mangoldtova funkcija. U drugom poglavlju donosimo definiciju i tvrdnje vezane za Dirichletov produkt aritmetičkih funkcija, dok se u trećem poglavlju bavimo generalizacijom konvolucije. U posljednjem poglavlju definiramo derivaciju aritmetičke funkcije te opisujemo njezina svojstava i dokazujemo Selbergov identitet.In this thesis, we describe some arithmetic functions of the theory of numbers. Thesis is divided into four chapters. In the first chapter, we provide basic definitions and properties of multiplicative functions and additive functions. We also describe particular functions such as: Euler function, sum of divisor function, divisor function, Liouville function, Möbius function, the number of distinct prime factors and the von Mangoldt function. In the second chapter, we provide an overview of basic definition and claims related to the Dirichlet product of arithmetic functions, while in the third chapter we define the generalized convolutions. In the last chapter, we define the derivation of arithmetic functions, describe its properties, and prove the Selberg identity

Mining industry in the knowledge economy

With the appearance of the knowledge economy, it is of the utmost importance for the mining industry to be involved in the global world trends and to develop its activity field in the areas which have knowledge as a resource in their base, such as development of new and advancement of old exploitation technologies, mining equipment and technology development, introduction of knowledge management in mining corporations, development the new technologies for environmental protection, implementation the new technologies in research works for faster, more reliable and cheaper finding of mine deposits and development of workers' knowledge, as a human resource in the mining industry. The aim of this work is to show that, although the added value of the companies in the mining industry in the last decade was created by the increase in the raw material prices in the world market, the knowledge economy is the path which the mining industry must negotiate in order to enter the XXI century

The effect of low-dose spermidine supplementation on polyamine content and antioxidative defence mechanisms in honey bees

Summary. The honey bee, a widespread pollinator, contributes to the conservation of biodiversity. In recent decades, a trend of declining colony numbers has emerged. The unsustainable exploitation of the environment may be the cause of this phenomenon. One protective strategy of organisms is to strengthen their antioxidative capacity. A class of positively charged molecules, polyamines, plays important roles in various cellular processes. They exert a regulatory effect on gene expression, have antioxidative properties, and promote longevity in model organisms. The three main representatives are putrescine, spermidine and spermine. The aim of this study was to determine whether supplementation of bees with low-dose spermidine leads to an increased level of the mentioned polyamines and whether this could strengthen the antioxidative defence system. Two experimental groups were established: C group (control), fed with a 50% (w/v) sucrose solution, and S0.01 group, whose diet was supplemented with 0.01 mM spermidine. The experiment lasted for 10 and 17 days. A significant increase in putrescine, spermidine and spermine content was noted in the supplemented group after 17 days, compared to its control. These results show a positive impact of spermidine supplementation on maintaining polyamine levels throughout aging. FRAP and MDA biochemical assays were used for the assessment of oxidative status. FRAP assay showed increased antioxidative capacity in the S0.01 group. These results are in accordance with the results obtained from the MDA assay, which showed a decreased level of lipid peroxidation in the supplemented group, in comparison to the control. The potential practical outcome of this study could be the use of spermidine in beekeeping practice to promote overall honey bee health

Seasonal changes of naturally occurring radionuclides and fallout 137-Cs in the samples of leaves of deciduous trees

Specifična aktivnost prirodnih radionuklida 238U, 235U, 226Ra, 210Pb, 232Th i 40K i proizvedenog 137Cs je merena u uzorcima lišća dve vrste listopadnog drveća, kestena (Aesculus hippocastanum) i lipe (Tilia spp) koji potiču iz tri gradska parka na užem području Beograda. Uzorci su sakupljani u vreme prolećne (n=7), letnje (n=2) i jesenje (n=8) sezone u periodu od 2002-2012. godine. Iz svake pojedinačne sezone uzorci lišća su spojeni po vrstama pri čemu je dobijen jedan integralni (sezonski) uzorak za svaki ispitivani park čime je postignuta veća efikasnost detekcije niskog nivoa gama zračenja. Za određivanje aktivnosti primenjen je metod spektrometrije gama emitera. U svim pojedinačnim uzorcima suve materije lišća detekcija radionuklida 210Pb i 40K je bila moguća i njihova specifična aktivnost se nalazila intervalu 15-52 Bq/kg i 310-650 Bq/kg, respektivno. Iako je aktivnost 226Ra bila veoma niska, u intervalu 0,5-5,6 Bq/kg, ovaj radionuklid je bio izmeren u svim uzorcima (osim u dva) i svim sezonama. Aktivnost 210Pb i 226Ra se povećavala tokom godine, pri čemu su njihove najveće vrednosti izmerene u lišću kestena u letnjoj sezoni. Suprotno, aktivnost 40K u lišću lipe i kestena je opadala tokom godine. Za razliku od prethodno navedenih, radionuklidi 238U, 235U i 232Th su retko detektovani samo u letnjem i/ili jesenjem periodu i po četiri uzorka lišća su sadržali 238U (2,7-11,7 Bq/kg) i 235U (0,13-1,0 Bq/kg), a tri 232Th (1,8-3,3 Bq/kg). Proizvedeni radionuklid 137Cs detektovan je u svim uzorcima lišća (osim u dva), a bez jasnog trenda ponašanja po sezonama i nalazio se u intervalu 0,3-1,2 Bq/kg. Cilj rada bio je ispitivanje akumulacije prirodnih radionuklida i njihovog potencijalnog variranja tokom godine u lišću listopadnog drveća.The specific activity of naturally occurring radionuclides 238U, 235U, 226Ra, 210Pb, 232Th, and 40K and fallout 137Cs was measured in the samples of leaves of two deciduous tree species, chestnut (Aesculus hippocastanum) and linden (Tilia spp.) common for the Belgrade urban area. Samples were collected in the spring (n = 7), summer (n = 2) and autumn (n = 8) during the vegetation period from 2002 to 2012. From each season, samples of leaves were combined according to two species and one single integral (seasonal) sample was obtained in order to improve detection efficiency of low gamma radiation level. Specific activities were determined using the gamma-ray spectrometry method. 210Pb and 40K radionuclides were detected in all the samples of leaves and their specific activity was in the range (Bq/kg dry weight): 15 - 52 and 310 - 650, respectively. Although the 226Ra level was very low and in the range from 0.5 - 5.6 Bq/kg, this radionuclide has been measured in all samples (except in the two) and each season. 210Pb and 226Ra activity increased during the vegetation period and their highest values were found in the leaves of chestnut trees in the summer season. In contrast, the activity of 40K in the leaves of linden and chestnut has decreased. Detection 238U, 235U and 232Th radionuclides was scarce and only in the summer and/or autumn. Four samples of leaves contained 238U (2.7 - 11.7 Bq/kg dry wt) and 235U (0,13 - 1.0 Bq/kg dry wt) and three of them 232Th (1.8 - 3.3 Bq/kg dry wt). Man-made radionuclide 137Cs (0.3-1.2 Bq/kg dry wt) was detected in all samples of leaves (except in two) and no clear trend according to seasons was found. The aim was to investigate the accumulation of naturally occurring radionuclides and fallout 137Cs in the leaves of deciduous trees and their potential variations during the vegetation period

Seasonal variations of naturally occurring radionuclides and 137cs in the leaves of deciduous tree species at sites of background radioactivity levels

Activity concentration of natural radionuclides and 137Cs were studied in leaves of the deciduous trees. In the spring and autumn season, leaves were collected in the area of normal background radiation levels represented by city parks in a multi-year period (2002-2012). Measurements by means of gamma-ray spectrometry showed 226Ra and 210Pb seasonal accumulation in leaves, while 238U and 235U could be detected only in autumn. Difference between seasons was not found significant for 40K and 137Cs. The study of radionuclides transfer factors was conducted by analyzing its relationships with basic soil properties at the beginning and the end of the vegetation period. © 2019, Editura Academiei Romane. All rights reserved

Seasonal changes of naturally occurring radionuclides and fallout 137-Cs in the samples of leaves of deciduous trees

Specifična aktivnost prirodnih radionuklida 238U, 235U, 226Ra, 210Pb, 232Th i 40K i proizvedenog 137Cs je merena u uzorcima lišća dve vrste listopadnog drveća, kestena (Aesculus hippocastanum) i lipe (Tilia spp) koji potiču iz tri gradska parka na užem području Beograda. Uzorci su sakupljani u vreme prolećne (n=7), letnje (n=2) i jesenje (n=8) sezone u periodu od 2002-2012. godine. Iz svake pojedinačne sezone uzorci lišća su spojeni po vrstama pri čemu je dobijen jedan integralni (sezonski) uzorak za svaki ispitivani park čime je postignuta veća efikasnost detekcije niskog nivoa gama zračenja. Za određivanje aktivnosti primenjen je metod spektrometrije gama emitera. U svim pojedinačnim uzorcima suve materije lišća detekcija radionuklida 210Pb i 40K je bila moguća i njihova specifična aktivnost se nalazila intervalu 15-52 Bq/kg i 310-650 Bq/kg, respektivno. Iako je aktivnost 226Ra bila veoma niska, u intervalu 0,5-5,6 Bq/kg, ovaj radionuklid je bio izmeren u svim uzorcima (osim u dva) i svim sezonama. Aktivnost 210Pb i 226Ra se povećavala tokom godine, pri čemu su njihove najveće vrednosti izmerene u lišću kestena u letnjoj sezoni. Suprotno, aktivnost 40K u lišću lipe i kestena je opadala tokom godine. Za razliku od prethodno navedenih, radionuklidi 238U, 235U i 232Th su retko detektovani samo u letnjem i/ili jesenjem periodu i po četiri uzorka lišća su sadržali 238U (2,7-11,7 Bq/kg) i 235U (0,13-1,0 Bq/kg), a tri 232Th (1,8-3,3 Bq/kg). Proizvedeni radionuklid 137Cs detektovan je u svim uzorcima lišća (osim u dva), a bez jasnog trenda ponašanja po sezonama i nalazio se u intervalu 0,3-1,2 Bq/kg. Cilj rada bio je ispitivanje akumulacije prirodnih radionuklida i njihovog potencijalnog variranja tokom godine u lišću listopadnog drveća.The specific activity of naturally occurring radionuclides 238U, 235U, 226Ra, 210Pb, 232Th, and 40K and fallout 137Cs was measured in the samples of leaves of two deciduous tree species, chestnut (Aesculus hippocastanum) and linden (Tilia spp.) common for the Belgrade urban area. Samples were collected in the spring (n = 7), summer (n = 2) and autumn (n = 8) during the vegetation period from 2002 to 2012. From each season, samples of leaves were combined according to two species and one single integral (seasonal) sample was obtained in order to improve detection efficiency of low gamma radiation level. Specific activities were determined using the gamma-ray spectrometry method. 210Pb and 40K radionuclides were detected in all the samples of leaves and their specific activity was in the range (Bq/kg dry weight): 15 - 52 and 310 - 650, respectively. Although the 226Ra level was very low and in the range from 0.5 - 5.6 Bq/kg, this radionuclide has been measured in all samples (except in the two) and each season. 210Pb and 226Ra activity increased during the vegetation period and their highest values were found in the leaves of chestnut trees in the summer season. In contrast, the activity of 40K in the leaves of linden and chestnut has decreased. Detection 238U, 235U and 232Th radionuclides was scarce and only in the summer and/or autumn. Four samples of leaves contained 238U (2.7 - 11.7 Bq/kg dry wt) and 235U (0,13 - 1.0 Bq/kg dry wt) and three of them 232Th (1.8 - 3.3 Bq/kg dry wt). Man-made radionuclide 137Cs (0.3-1.2 Bq/kg dry wt) was detected in all samples of leaves (except in two) and no clear trend according to seasons was found. The aim was to investigate the accumulation of naturally occurring radionuclides and fallout 137Cs in the leaves of deciduous trees and their potential variations during the vegetation period

Seasonal variations of naturally occurring radionuclides and 137cs in the leaves of deciduous tree species at sites of background radioactivity levels

Activity concentration of natural radionuclides and 137Cs were studied in leaves of the deciduous trees. In the spring and autumn season, leaves were collected in the area of normal background radiation levels represented by city parks in a multi-year period (2002-2012). Measurements by means of gamma-ray spectrometry showed 226Ra and 210Pb seasonal accumulation in leaves, while 238U and 235U could be detected only in autumn. Difference between seasons was not found significant for 40K and 137Cs. The study of radionuclides transfer factors was conducted by analyzing its relationships with basic soil properties at the beginning and the end of the vegetation period. © 2019, Editura Academiei Romane. All rights reserved

Synthesis, characterization and biological activity of platinum(II) and palladium(II) complexes with quinoline derivatives of thiosemicarbazones

The aim of this study was to elucidate the structure, geometry and biological activity of platinum(II) and palladium(II) complexes with different quinoline derivatives of thiosemicar-bazones. Four novel platinum(II) and palladium(II) complexes with 2-quinolinecarboxaldehyde thiosemikarbazone (H2QATSC) and 8-quinolinecarboxaldehyde thiosemikarbazone (H8QATSC) were synthesized. The complexes of platinum(II) and palladium(II) with H2QATSC ligand, [PtCl(2QATSC)] (1) and [PdCl(2QATSC)] (2), were synthesized by direct reaction and charac-terized by single crystal X-ray analysis. The complexes of platinum(II) and palladium(II) with H8QATSC ligand, [PtCl(8QATSC)] (3) and [PdCl(8QATSC)] (4), were characterized by NMR spectroscopy. In the complexes 1–4 ligands are coordinated tridentately via the quinoline and imine nitrogen atoms and thiosemicarbazone sulfur atom, forming two five-membered rings with metal ion. The geometry around metal ions is square-planar, where chloride ion occupies fourth coordination site. Antitumor activity of the complexes 1–4 was investigated and com-pared with the activity of cisplatin

Progress in the production of bioethanol on starch-based feedstocks

Bioethanol produced from renewable biomass, such as sugar, starch, or lignocellulosic materials, is one of the alternative energy resources, which is both renewable and environmentally friendly. Although, the priority in global future ethanol production is put on lignocellulosic processing, which is considered as one of the most promising second-generation biofuel technologies, the utilizetion of lignocellulosic material for fuel ethanol is still under improvement. Sugar- based (molasses, sugar cane, sugar beet) and starch-based (corn, wheat, triticale, potato, rice, etc.) feedstock are still currently predominant at the industrial level and they are, so far, economically favorable compared to lingocelluloses. Currently, approx. 80 % of total world ethanol production is obtained from the fermentation of simple sugars by yeast. In Serbia, one of the most suitable and available agricultural raw material for the industrial ethanol production are cereals such as corn, wheat and triticale. In addition, surpluses of this feedstock are being produced in our country constantly. In this paper, a brief review of the state of the art in bioethanol production and biomass availability is given, pointing out the progress possibilities on starch-based production. The progress possibilities are discussed in the domain of feedstock choice and pretreatment, optimization of fermentation, process integration and utilization of the process byproducts