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Srpska Crna Gora - savremene geografske promene u funkciji regionalnog razvoja

Srpska Crna Gora - contemporary geographical changes in the function of regional development

Predmet proučavanja doktorske disertacije je Srpska Crna Gora (Užička Crna Go- ra), regionalna celina u slivu Skrapeža, sa središtem u Kosjeriću. Tokom druge polovi- ne 20. i početkom 21. veka proučavana teritorija je zahvaćena demografskim, fizionom- skim i funkcionalnim promenama koje su uticale na njenu geografsku transformaciju. Osnovni cilj istraživanja je naučno utemeljeno saznanje o izvršenim geografskim pro- menama i njihovom uticaju na regionalni razvoj, tj. uočavanje, definisanje i hronološko praćenje preobražaja geografskog prostora radi planiranja budućeg razvoja. To podrazu- meva objektivno i kompleksno sagledavanje promena fizionomskih i funkcionalnih obeležja, ukazivanje na glavne nosioce tih promena, i utvrđivanje prioriteta budućeg regionalnog razvoja. Kako bi se došlo do relevantnih naučnih saznanja i zaključaka, sav- remene geografske promene praćene su kroz uzročno-posledično delovanje prirodnih i socioekonomskih procesa, prostorno i vremenski. Intenzitet izvršenih promena je de- terminisan interakcijom unutrašnjih i spoljnih socioekonomskih faktora, dok je uti- caj prirodnih procesa slabije izražen. Promene fizičkogeografskih elemenata u istraživanom periodu bile su mini- malne i nisu ispoljile značajniji uticaj na regionalni razvoj. Najveće promene prirod- nih elemenata geografske sredine odnose se na promene intenziteta erozije i širenje šumskog pokrivača usled depopulacije i pošumljavanja, kao i zagađivanje vazduha u Kos- jerićkoj kotlini usled razvoja industrije cementa. Težište istraživanja se odnosi na uzroke i posledice znatno dinamičnijih demo- grafskih, ekonomskih i naseobinskih promena, koje su u najvećoj meri uticale na trans- formaciju prostora i dinamiku ukupnog regionalnog razvoja. Ove promene su u prostor- nom smislu bile polarizovane, stvarajući razvojni jaz između Kosjerića i ruralnog dela Srpske Crne Gore. Demografske promene su bile izrazito negativne i odvijale su se u pravcu depopu- lacije i konstantnog pogoršanja osnovnih vitalnih elemenata stanovništva. Ove pro- mene su analizirane u kontekstu savremenih socioekonomskih procesa, koji su uslovili depopulaciju regije, ali i prerazmeštaj stanovništva unutar njenih granica. Kao rezul- tat tih procesa, u drugoj deceniji 21. veka stanje ljudskih resursa u regiji je loše. Sve manji broj stanovnika, izrazito stara populacija, nizak socijalni kapital i nedostatak radne snage u poljoprivredi u većini seoskih naselja predstavljaju glavne limitirajuće faktore u planiranju budućeg razvoja. Ekonomsko-geografske promene su se odvijale pod uticajem dominantne industri- jalizacije i deagrarizacije. To je dovelo do temeljnih promena u privrednoj strukturi regije i socioekonomskog transfera stanovništva iz primarnog sektora u neagrarne delatnosti. Naglasak na razvoju industrije, uz istovremenu opštu nebrigu za probleme sela i poljoprivrede, bio je glavni pokretač negativnih demografskih promena u većem delu regije. Ekonomsko-geografski procesi su bili praćeni i promenama u demografskoj, fizionomskoj i funkcionalnoj strukturi naselja, pri čemu je najveći uticaj na njihovu transformaciju u drugoj polovini 20. veka imao proces urbanizacije. Kosjerić se razvio u regionalno središte, koje u hijerarhijskoj mreži naselja zauzima centralno mesto. Tako formiran monocentrični naseobinski sistem, bez postojanja funkcionalno jačih seoskih naselja, javlja se kao ograničavajući faktor ravnomernog regionalnog razvoja jer neprekidno pojačava procese koncentracije stanovništva i aktivnosti u centralnom naselju. Analizom izvršenih promena i njihovog uticaja na stanovništvo i privredu, nas- tojali smo da utvrdimo realne razvojne mogućnosti i ograničenja. To podrazumeva i utvrđivanje postojećih razvojnih neravnomernosti i mogućnosti revitalizacije, u cilju dostizanja ravnomernog prostorno-funkcionalnog razvoja i očuvanja geografskog iden- titeta regije. Regionalni razvoj u Srpskoj Crnoj Gori je do sredine 20. veka bio ravnome- ran, jer u homogenom agrarnom prostoru nisu bile ispoljene veće razlike u stepenu raz- vijenosti između pojedinih naselja. Procesi prostorne polarizacije stanovništva i funkcija počinju 50–ih i 60–ih godina 20. veka, a dobijaju na punom intenzitetu sa in- dustrijalizacijom Kosjerića posle 1970. godine. Iako je u socijalističkom društvenom sistemu ekonomski razvoj planski usmeravan, odvijao se u uslovima favorizovanja indus- trije i negativnog stava prema poljoprivredi i selu. Na taj način, izvršene geografske promene dovele su do narušavanja ravnomernosti u razvoju i stvaranja izrazito polari- zovane prostorne strukture demografskih, socioekonomskih i naseobinskih elemenata. Iako je u posmatranom periodu došlo do značajnog ukupnog ekonomskog napretka, geo- grafske promene u Srpskoj Crnoj Gori su negativno delovale na stanje ljudskih resursa i stepen iskorišćavanja lokalnih potencijala, izazivajući sve veće zaostajanje seoskih naselja u odnosu na urbani centar regije. Neravnomeran ekonomski i demografski razvoj između Kosjerićke kotline i planinskog oboda jedan je od osnovnih razvojnih problema regije. Rešavanje tog problema, u cilju ravnomernijeg regionalnog razvoja, predstavlja- lo je poseban naučni izazov. Proučavanje geografskih promena u regiji omogućilo je izvođenje zaključaka, na os- novu kojih je moguće predložiti konkretne mere za njenu demografsku i socioekonomsku revitalizaciju. Uočene prostorne neravnomernosti ukazuju da pravci budućeg regional- nog razvoja Srpske Crne Gore treba da imaju za cilj ublažavanje nesklada između grad- skog i seoskih naselja, Kosjerićke kotline i planinskog prostora. Osnovni cilj uspora- vanja negativnih tendencija i smanjivanja regionalnih razlika je revitalizacija seos- kih naselja i stvaranje povoljnijih uslova za život na selu. Pravci regionalnog razvoja Srpske Crne Gore u budućnosti vezani su za: održivi razvoj poljoprivrede i seoskog tu- rizma, decentralizaciju industrije i modernizaciju seoske infrastrukture, što zahte- va veće angažovanje predstavnika lokalne samouprave i značajna materijalna ulaganja. I pored preduzimanja određenih mera u cilju razvoja ruralnog dela Srpske Crne Go- re, postojeće stanje jasno ukazuje da će se i u budućnosti nastaviti negativni demograf- ski i socioekonomski procesi. Prilikom planiranja razvoja treba uvažiti realnost na terenu, tj. prihvatiti činjenicu da je većina ruralnih naselja u regiji već toliko devas- tirana da revitalizacija nije moguća, ili zahteva velika ulaganja, zbog čega nije eko- nomski opravdana. U sadašnjim demografskim, ekonomskim i društveno-političkim okolnostima, razvojna ravnoteža u regiji je teško ostvariva. Stoga će i u narednom pe- riodu Kosjerić ostati demografski i ekonomski pol regije, ali će njegov funkcionalni kapacitet slabiti kao rezultat depopulacije. Na drugoj strani, razvoj većine seoskih naselja će se u uslovima totalne depopulacije, nedostatka radne snage i slabih neagrar- nih funkcija, kretati u pravcu biološkog i socioekonomskog gašenja.

Subject of the doctoral dissertation is Srpska Crna Gora (Užička Crna Gora), region that is located in the basin of river Skrapež, with the center in Kosjerić. From the mid-20th century to the present, the territory being studied are identified demographic, physiognomic and functional changes that affect its geographic transformation. The main objective of the research is scientifically based knowledge of the executed geographical changes and their impact on regional development, ie. identification, defining and chronological monitoring of transfor- mation of geographical space in order to plan future development. This includes objective and complex consideration of changes physiognomic and functional characteristics, pointing to the main holders of these changes, and setting priorities for future regional development. In order to reach the relevant scientific findings and conclusions of contemporary geographical changes were monitored through causal and spatio-temporal connection of natural and socio-economic processes. The intensity of such changes is determined by the interaction of internal and external socio-economic factors. The impact of natural processes was less pronounced. Changes to the natural elements in the study period were minimal and did not have a significant impact on regional development. The biggest changes are related to changes in the intensity of erosion and the spread of forest cover due to depopulation and reforestation, as well as air pollution in Kosjeric basin due to the development of the cement industry. Focus of research is relating to the causes and consequences of significantly more dynamic demographic, economic and settlement changes, which are largely influenced the transfor- mation of space and dynamics of the overall regional development. These changes in spatial terms were polarized, creating a development gap between Kosjerić and rural areas of Srpska Crna Gora. Demographic changes were extremely negative. They relate to the population reduction and the constant deterioration of basic vital elements of the population. These changes are analyzed in the context of contemporary socio-economic processes, which have caused depopulation of the region, but also the relocation of the population within its borders. As a result of these processes, in the second decade of the 21st century, the state of human resources in the region is poor. Fewer and fewer people, very old population, low social capital and labor shortages in agriculture in most rural settlements are the main limiting factors in planning future development. Changes in the economy have taken place under the dominant influence of industrialization and deagrarization. This has led to fundamental changes in the economic structure of the region and socioeconomic transfers of population from the primary sector in non-agrarian activities. The emphasis on the development of the industry, at the same time the general neglect of the problem of agriculture and rural areas, was the main driver of negative demographic changes in most part of the region. Economic processes were followed and changes in the demographic, physiognomic and functional structure of the settlements. The greatest impact on their transformation in the second half of the 20th century was the process of urbanization. Kosjerić has developed into a regional center, which has a central place in the hierarchical network of settlements. Thus formed monocentric settlement system without functional strengths of rural settlements, is the limiting factor of balanced regional development. The concentration of population and activities in a central place is continuously increasing. By analyzing the geographical changes and their impact on the population and economy, we have tried to determine the real development possibilities and limitations. This includes the identification of existing development imbalances and the possibility of revitalization, in order to achieve a balanced spatial and functional development and preservation of geographical identity of the region. Regional development in Serbian Montenegro until the mid-20th century was balanced, because in a homogeneous agricultural space there were no major differences in levels of development between the individual settlements. The processes of spatial polarization of population and economy are beginning the 50s and 60s of the 20th century, and receive the full intensity of industrialization Kosjerić after 1970. Although the socialist society economic development was influenced by the state, took place in conditions favoring the industry and negative attitudes towards agriculture and rural areas. In this way, the enforced geographical changes have led to a disruption of uniformity in the development and creation of highly polarized spatial structure of demographic, socioeconomic and settlement elements. Although in the research period there was a significant overall economic development, geographical changes in Srpska Crna Gora are adversely affect human resources and level of use of local resources, causing increasing backwardness of rural settlements in relation to the urban center of the region. Different economic and demographic development between Kosjerić valley and the mountain area is one of the basic development problems of the region. Solving this problem in order to balanced regional development, was a special scientific challenge. The study of geographical changes in the region allow to draw conclusions on the basis of which it is possible to propose concrete actions for its demographic and socio-economic revitalization. The observed spatial disparities indicate that the directions of future regional development of Srpska Crna Gora should aim to narrow the gap between urban and rural settlements, Kosjerić valley and the mountain area. The main objective of slowing down the negative trends and to reduce regional disparities is the revitalization of rural settlements and the creation of favorable conditions for life in the village. Directions of regional development of Srpska Crna Gora in the future are related to: sustainable development of agriculture and rural tourism, industry decentralization and modernization of rural infrastructure. This requires greater involvement of representatives of local government and significant financial investment. Despite taking certain actions in order to develop the rural part of Srpska Crna Gora, the current situation clearly indicates that the negative demographic and socioeconomic processes continue in the future. In planning future development, should take into account the demographic reality, and accept the fact that most of the rural settlements in the region already so devastated that revitalization is not possible or requires a big investment, which is not economically viable. In the current demographic, economic and socio-political circumstances, balanced development in the region is difficult to achieve. Therefore, in the following period Kosjerić stay demographic and economic pole in the region, but its functional capacity impairment as a result of depopulation. On the other hand, in terms of total depopulation, labor shortages and weak non-agrarian functions, development of most rural settlements will move in the direction of a gradual biological and socio-economic shutdowns.

Genetička i epigenetička studija pleomorfnih adenoma pljuvačnih žlezda čoveka mutacioni status HER-2, C-MYC, H-RAS I TP53 gena i metilacioni status P14 i P16 gena

mutational status of HER-2, C-MYC, H-RAS and TP53 genes and methylation status of P14 and P16 genes

Uvod: Pleomorfni adenom (PA) je spororastući benigni tumor koji se obično javlja u petoj deceniji života i mnogo se češće razvija kod žena. Najčešće pogađa velike pljuvačne žlezde, a čak u preko 70% slučajeva lokalizovan je u zaušnoj (parotidnoj) pljuvačnoj žlezdi. Uglavnom se uspešno leči hirurški, ali je ipak to jedini benigni tumor pljuvačnih žlezda koji pokazuje sklonost ka malignoj transformaciji u karcinom u pleomorfnom adenomu (CXPA). U prvim, citogenetičkim studijama, analizom kariotipa pokazano je u najvećem broju slučajeva prisustvo karakteristične hromozomske translokacije koja uključuje PLAG1 ili HMGA2 gene. Međutim, kod ovih, kao i kod tumora sa neizmenjenim kariotipom, u nastanak i progresiju tumora su uključeni i drugi mehanizmi. Narušena mitogena signalna kaskada, koja u normalnim fiziološkim uslovima započinje na receptorima za faktore rasta (HER-2 npr.), jedan je od ključnih mehanizama odgovornih za rast tumorske mase. Aberantni mitogeni signal može takođe biti generisan i endogeno kao rezultat mutacione aktivacije onko-proteina iz familije Ras. Jedan od mogućih mehanizama prenosa mitogenog signala realizuje se preko ciklin zavisnih kinaza, čiji je snažni regulator protein p16. Mitogeni signal prenosi se dalje u nukleus gde, između ostalih c-myc, stimuliše transkripciju gena uključenih u ćelijsku deobu. Ukoliko se u genomu dogode oštećenja, jedan od ključnih tumor supresorskih gena – TP53, zaustaviće ćelijski ciklus i/ili ćeliju uvesti u apoptozu. Jedan od pozitivnih regulatora p53 funkcije je p14, koji vezuje Mdm2, čime onemogućava formiranje Mdm2/p53 inhibitornog kompleksa. Na funkciju i stabilnost ovih proteina mogu da utiču različite mutacije, a na nivo ekspresije različiti epigenetički mehanizmi, u prvom redu metilacija promotora. Cilj: Cilj ove doktorske disertacije je ispitivanje povezanosti mutacija u genima HER-2, c-myc, H-ras i TP53, kao i metilacionog statusa promotora p16 i p14 gena sa nastankom, progresijom i malignom transformacijom pleomorfnih adenoma parotidnih pljuvačnih žlezda. Materijal i metode: Eksperimentalna grupa je obuhvatala 60 pacijenata sa dijagnostikovanim PA i 12 sa CXPA. Genomska DNK je izolovana iz isečaka tumorskog tkiva ukalupljenog u parafinu. Metodom lančane reakcije polimeraze u realnom vremenu (real time PCR) analizirane su amplifikacije gena HER-2 i c-myc; metodom konformacijskog polimorfizma jednolančanih segmenata DNK, uz potvrdu sekvenciranjem, analizirani su mutacioni statusi H-ras i TP53 gena; metil specifičnim PCR-om utvrđen je metilacioni status promotora p16 i p14 gena. Hi kvadrat test i Fišerov test egzaktne verovatnoće korišćeni su za utvrđivanje razlika u distribuciji učestalosti mutacija i epimutacija u grupama (podela prema uzrastu, kliničkom ili patohistološkom nalazu, kao i među grupama - adenomi i karcinomi). Logističkom regresionom analizom ispitivani su genetički ili epigenetički prediktori maligne transformacije. Dobijeni rezultati su obrađeni statističkim programom SPSS 17.0. Rezultati: Amplifikacija HER-2 onkogena utvrđena je kod 18% pacijenata sa PA i kod 42% pacijenata sa CXPA, dok je amplifikacija c-myc utvrđena kod svega 8% pacijenata sa PA i kod 33% pacijenata sa CXPA. Prisustvo mutacije u H-ras genu utvrđeno je u 15% PA i u 33% CXPA. U kodirajućim egzonima TP53 gena mutaciju je imalo 25% pacijenata sa PA, i čak 75% pacijenata sa CXPA. Metilacija promotora p16 gena utvrđena je u 67% adenoma i 67% karcinoma, a p14 gena u 70% adenoma i 83% karcinoma. Nije uočeno postojanje asocijacije između mutacija ili epigenetičkih promena sa polom, uzrastom ili lošim navikama (pušenje i konzumacija alkohola), kao ni sa kliničkim ili patohistološkim parametrima. Poređenjem učestalosti mutacija i epigenetičkih promena u grupi pleomorfnih adenoma i karcinoma u pleomorfnom adenomu pokazano je da postoji statistički značajna razlika u učestalosti mutacija c-myc gena (p=0,037, Fišer) i TP53 gena (p=0,002, Fišer) između ispitivanih grupa. Zaključak: Ovim istraživanjem pokazana je visoka zastupljenost mutacija i epigenetičkih promena u ispitivanim genima. Epienetičke promene u regionu CDKN2A lokusa predstavljaju izuzetno značajan molekularni mehanizam u patogenezi pleomorfnog adenoma. Pokazano je da prisustvo genske amplifikacije c-myc 5,5 puta povećava šanse za malignu transformaciju pleomorfnog adenoma, dok prisustvo TP53 mutacija čak 9 puta povećava šanse za malignu transformaciju.

Introduction: Pleomorphic adenoma (PA) is a slow-growing benign tumor that usually develops in the fourth or fifth decade of life, more often in women. It is mostly found in the major salivary glands, and over 70% are localized in the parotid salivary gland. Surgical removal is usually successful and the patient is cured. However it is the only benign salivary gland tumor with a tendency toward malignant transformation into carcinoma ex pleomorphic adenoma (CXPA). PAs have been extensively studied from a cytogenetic point of view and indeed the presence of specific chromosomal translocations involving PLAG1 or HMGA2 gene loci have been reported in many instances. There has been much less studies on other molecular events potentially involved in tumor development and progression. Disruption of the mitotic signaling cascade is one of the key mechanisms responsible for tumor growth. The aberrant signaling does not necessarily start from growth factors and their receptors. It may be generated endogenously, for instance from the mutated Ras protein. One possible transmission of the mitogen signal is through cyclin dependent kinases that are strongly regulated by the p16 protein. The signal is transmitted to the nucleus where c-myc, among others, stimulates the transcription of the cell cycle regulatory genes. Accumulation of DNA damage leads to cell cycle arrest and programmed cell death under the control of p53. p14 interactions with Mdm2 initiate p53-dependant cell cycle arrest and apoptosis. Lack of p14 results in higher levels of Mdm2 and p53 inhibition. Expression, function and stability of these cancer gene products may be considerably affected by mutations, and epimutations – primarly gene promoter methylation. Aim: The aim of this doctoral dissertation was to assess the frequency and thus the relevance of mutations in HER-2, c-myc, H-ras and TP53 genes, as well as methylation status of p16 and p14 gene promoters in the development, progression and malignant transformation of pleomorphic adenoma of parotid salivary glands. Material and Methods: The study group included 60 patients diagnosed with PA and 12 diagnosed with CXPA. Genomic DNA was extracted from paraffin embedded tumor tissue. Gene amplifications of HER-2 and c-myc genes was analyzed by real time polymerase chain reaction (real time PCR); the presence of mutations in the coding regions of H-ras and TP53 genes was analyzed by single strand conformation polymorphism analysis and validated by sequencing; gene promoter methylation status of p16 and p14 genes was assessed by methylation specific PCR. Chi square test and Fisher exact test were used to analyze the differences in the distribution of mutations and epigenetic lesions among specific groups (according to age, clinical or pathohistological findings, as well as between groups – adenomas and carcinomas). Logistic regression analysis was used to assess genetic and/or epigenetic predictors of malignant transformation. Calculations were performed using SPSS 17.0 statistical software. Results: Gene amplification of HER-2 oncogene was found in 18% of PA patients and in 42% of CXPA patients, whilst gene amplification of c-myc oncogene was found in only 8% of PA patients and in 33% of CXPA patients. The presence of H- ras gene mutation was found in 15% of PA and in 33% of CXPA. Mutations in the coding regions of TP53 gene were detected in 25% of PA patients, and as high as 75% of CXPA patients. The prevalence of p16 gene promoter methylation was 67% in both adenoma and carcinoma groups, and p14 gene promoter methylation was 70% in the adenoma group and 83% in the carcinoma group. No association was found between mutations and/or epigenetic changes with gender, age or bad habits (smoking and alcohol consumption), nor with clinical and pathohistological findings. Comparison of mutation prevalence and epigenetic changes between PA and CXPA group showed the presence of statistically significant difference in the distribution of c-myc (p=0.037, Fisher) and TP53 mutations (p=0.002, Fisher). Conclusion: This research showed a relatively high prevalence of mutations in the HER/ras/myc signaling cascade genes and also established the importance of p14 and p16 gene promoter methylation. Epigenetic changes in the CDKN2A locus represent a critical event in pleomorphic adenoma pathogenesis. It was also demonstrated that the presence of c-myc oncogene amplification increases the chance for malignant transformation 5.5 times, whilst the presence of TP53 mutations leads to a 9-fold increase in chance for malignant transformation.

Model ćelija C6 glioma pacova kao oruđe za pronalaženje novih terapeutskih strategija: karakterizacija rezistentnog fenotipa in vitro i in vivo

Rat C6 glioma model as a tool for discovering new ttherapeutic strategies: characterization of the resistant phenotype in vitro and in vivo

Uspešnost terapije glioblastoma, najĉešćeg i najagresivnijeg malignog tumora centralnog nervnog sistema, je osujećena usled visokog stepena invazivnosti, kao i pojave rezistencije na hemioterapiju. Cilj ove doktorske disertacije je bio da se uspostavi i okarakteriše rezistentni gliomski model koji bi imao primenu u ispitivanju novih terapeutskih strategija u leĉenju ove teške bolesti. Kao poĉetni materijal korišćena je pacovska C6 ćelijska linija glioma, fenotipski sliĉna humanim glioblastomima. Za uspostavljanje rezistencije korišćen je prvi odobreni antigliomski lek 1,3-bis(2-hloroetil)-1-nitrozoureom (BCNU, karmustin), alkilirajući agens koji se koristi u terapiji primarnih i rekurentnih glioblastoma. Kontinuirana primena BCNU je dovela do razvoja rezistencije C6 ćelija ne samo na ovaj hemioterapeutik, već i na druge DNK oštećujuće agense, cisplatin (CPt) i temozolomid (TMZ). Novouspostavljena rezistentna ćelijska linija je oznaĉena kao RC6. Ispitivanje mehanizama rezistencije je obuhvatilo analizu promena na nivou apoptotske mašinerije i oštećenja DNK lanaca, kao i analizu promena u antioksidativnom kapacitetu izmeĊu C6 i RC6 ćelija. Rezistentna RC6 linija pokazuje smanjenu osetljivost na indukciju ćelijske smrti koja je praćena smanjenjem ekspresije antiapoptotskog faktora Bcl-2, proapoptotskog faktora Bad i efektorske kaspaze 3 na nivou iRNK i proteina. TakoĊe je pokazano smanjenje ekspresije iRNK antiapoptoskog Bcl-Xl i proapoptotskog Bax-a. Razvoj rezistencije je doveo i do znaĉajnog povećanja produkcije reaktivnih kiseoniĉnih vrsta (ROS) i smanjenja odnosa koncentracije oksidovanog i redukovanog glutationa. Zapaţeno je povećanje ekspresije iRNK komponenti antioksidativnog sistema (MnSOD, iNOS, GPx i MRP1) i smanjenje ekspresije iRNK za HIF-1α kod RC6 ćelija u odnosu na C6 ćelije. RC6 ćelije pokazuju povećanu osetljivost na delovanje doksorubicina (DOX). UtvrĊeno je da RC6 ćelije akumuliraju više DOX-a od C6 ćelija ĉemu doprinosi znaĉajno smanjenje ekspresije iRNK za ABCB1 membranski transporter, kao i smanjenje unutarćelijskog pH. Pored toga, RC6 ćelije proliferišu znatno sporije u odnosu na C6 ćelije što je karakteristiĉno za rezistentne ćelije, ali i za ćelije sa većim invazivnim sposobnostima. Rezultati potvrĊuju da invazivnosti RC6 ćelija doprinosi povišena ekspresija iRNK za metaloproteinazu MMP9...

The most common and aggressive malignant tumor of the central nervous system is glioblastoma which successful treatment is compromised due to its high invasiveness, and resistance to chemotherapy. This study aimed to establish and characterize resistant glioma model for testing new therapeutic strategies for treatment of this serious disease. Rat C6 glioma cell line, which is phenotypically similar to human glioblastoma, was chosen as starting material. The first approved antiglioma drug, 1,3-bis (2-chloroethyl) -1-nitrosourea (BCNU, carmustine), an alkylating agent for treatment of primary and recurrent glioblastoma was used for establishing the resistant phenotype. Continuous treatment with BCNU led to the development of resistance not only to this chemotherapeutic, but also to other DNA damaging agents, cisplatin (CPt) and temozolomide (TMZ). The newly established drug resistant cell line was labeled as RC6. Resistance mechanisms analysis adressed the changes in apoptotic machinery and DNA damage, as well as the changes in antioxidant capacity between C6 and RC6 cells. Resistant RC6 line showed reduced sensitivity to cell death induction which was accompanied by a significant decrease in mRNA and protein expression of antiapoptotic factor Bcl-2, proapoptotic factor Bad and effector caspase 3. The mRNA expression of antiapoptotic factor Bcl-Xl and proapoptotic factor Bax was also decreased. The development of resistance was accompanied by significantly increased reactive oxygen species (ROS) production and decreased oxidized to reduced glutathione ratio. mRNA expression of antioxidant system components (MnSOD, iNOS, GPx and MRP1) was significantly increased in RC6 compared to C6 cells, while HIF-1α mRNA expression was decreased. RC6 cells exibited increased sensitivity to doxorubicin (DOX). It was determined that RC6 cells accumulated more DOX than C6 cells as a result of decreased mRNA expression of ABCB1 membrane transporter, as well as lower intracellular pH. In addition, RC6 cells proliferated significantly slower compared to C6 cells which is characteristic for drug resistant cells and cells with greater invasive capacity. The results confirmed that increased mRNA expression of metalloprotease MMP9 contributed to RC6 cells invasiveness...

Primena akvatičnih oligoheta (Tubificidae) u in situ i ex situ ekogenotoksikološkim istraživanjima

Application of aquatic oligochaetes (Tubificidae) in ecogenotoxicological in situ and ex situ studies

Familija Tubificidae (Oligochaeta), po brojnosti jedinki i po biomasi, je jedna od najznačajnijih grupa u zajednicama akvatičnih makroinvertebrata. Ovi organizmi su prepoznati kao pouzdani bioindikatorski organizmi koji se koriste u proceni ekološkog potencijala akvatičnih ekosistema. U ovoj studiji akvatične oligohete su korišćene kao eksperimentalni organizmi u ekogenotoksikološkim istraživanjima. Uticaj različitih stresora in situ, kao i odabranih grupa zagađivača ex situ na integritet DNK molekula celomocita i hemocita, praćen je komet testom, a za procenu nivoa oštećenja korišćen je parametar TI (eng. Tail intensity). In situ istraživanje rađeno je tokom 2014. i 2015. godine na lokalitetu Duboko (Sava), i tokom 2014. godine na lokalitetu Višnjica (Dunav) na vrsti Branchiura sowerbyi, i mešovitom uzorku tubificidnih vrsta (Mix uzorak). Rezultati ukazuju na osetljivost celomocita i hemocita u detekciji sredinskog stresa. Nivo oštećenja DNK molekula kod različitih vrsta imao je sličan trend pri odgovoru na sredinske uslove i pokazao je značajne korelacije sa praćenim mikrobiološkim i fizičko-hemijskim parametrima kvaliteta vode. Vodostaj je izdvojen kao bitan stresor koji je tokom istraživanja znatno uticao na ostale praćene parametre. Brojnost jedinki i divezitet populacija akvatičnih oligoheta se nije menjala sa promenom stresora (poplave, ispuštanje otpadnih voda, spiranje zemljišta), s druge strane, uticaj stresora bio je evidentan na oštećenje DNK molekula. U ex situ istraživanu praćen je uticaj citostatika 5–fluorouracila i etopozida, kao i model mutagena kadmijum hlorida, na nivo oštećenja DNK molekula vrste Limnodrilus udekemianus. Sve supstance su značajno povećale nivo oštećenja DNK molekula.

According to the number of individuals and their biomass, family Tubificidae (Oligochaeta) is one of the most important groups in the communities of aquatic macroinvertebrates. As bioindicators these organisms are used in the assessment of the ecological potential of aquatic ecosystems. In this study aquatic oligochaetes are used as experimental organisms in ecogenotoxicological assessment. For in situ studies impact of different stressors on the integrity of the DNA molecule of coelomocytes and haemocytes was evaluated, while the impact of a selected group of pollutants was studied ex situ. The comet assay was used for the evaluation of the genotoxic potential and parameter TI (Tail intensity) for the assessment of the level of DNA damage. In situ research was conducted on the species Branchiura sowerby and in the mixed sampled of tubificid species from the sampling sites Duboko (Sava) and Višnjica (Danube). Coelomocytes and haemocytes have shown to be sensitive to environmental stress. The level of DNA damage in different species showed a similar trend in response to environmental conditions and significantly correlated with microbial, physical and chemical water quality parameters. Water level was recognized as an important stressor that had significant impact on the other environmental parameters. Different stressors (floods, wastewater discharge, and runoffs) did not affect the number of individuals and the diversity of aquatic oligochaetes populations. On the other hand, the impact of stressors was evident on the level of DNA damage. The effects of cytostatic, 5-fluorouracil and etoposide and of model mutagen CdCl2, on the level of DNA damage of Limnodrilus udekemianus was examined ex situ. All tested substances significantly increased the level of DNA damage.

Ekoklimatske i balneološke karakteristike banjskih naselja sliva Južne Morave u funkciji održivog razvoja

Ecoclimatic and balneological features of spa settlements in Juzna Morava basin as function of sustainable development

Poznavanje klimatskih, bioklimatskih i balneoloških referenci značajno je za poznavanje lečilišnih i rekreativno-terapeutskih vrednosti banjskih i klimatskih mesta. U tom kontekstu smatramo važnim istaći i uticaj planetarnih klimatskih promena na ekoklimatske i bioklimatske vrednosti banjsko-klimatskih mesta, kao važnih lečilišnih, rekreativnih i ekoloških destinacija. U području sliva Južne Morave nalazi se 10 afirmisanih banjskih naselja: Bujanovačka Banja, Vranjska Banja, Sijerinska Banja, Prolom Banja, Kuršumlijska Banja, Lukovska Banja, Ribarska Banja, Sokobanja, Niška Banja i Zvonačka Banja. Ni jedna od ovih banja nema kvalitetno obrađene i kompletne bio-klimatske analize, te je bilo neophodno pristupiti izradi ozbiljnih klimatsko-bioklimatskih analiza u kojima bi se, pored balneološke slike, prezentirala lečilišno-terapeutsko- rekreativna mogućnost navedenih banjskih mesta. Istraživanja fizičko-geografskih karakteristika imaju zadatak da odgovore na osnovne prirodne predispozicije koje su uslovile termomineralne pojave, što je bila polazna osnova za formiranje banjskih mesta koja su se s vremenom razvila u banjska naselja. U pitanju je utvrđivanje prirodnih potencijala, njihove valorizacije, vodeći računa o pravilnom upravljanju i zaštiti čovekove životne sredine. Postojeće informacije u prospektima o banjama su neodređene i nestručne, pa se o pojedinim banjama govori kao o mestima koja imaju ,,zdrav planinski vazduh", ,,specifičnu ružu vetrova U cilju komletiranja slike potencijalnosti navedenih banjaskih mesta izneće se analiza ekoklimatskih i balneoloških karakteristika i staviti u funkciju i planiranja i razvoja datih mesta, koja su se vremenom transformisala u naselja. To podrazumeva i analizu klimatskih elemenata i kompleksnih klimatskih veza. U radu su analizirati klimatski elementi: temperatura vazduha, vlažnost vazduha, vazdušni pritisak, vetar, oblačnost i trajanje sunčevog sjaja, kako bi se shvatile osnovne karakteristike klime ovih mesta...

An insight into climatic, bioclimatic and balneological references is crucial to understanding healing and recreationally therapeutic spa and climatic place values. In the context given, it is important to emphasise the influence of global climatic changes on the eco climatic and bioclimatic values of spa climatic places as important healing, recreational and ecological destinations. There are ten formed spa settlements within the Juzna Morava Basin, which includes Bujanovacka Banja, Vranska Banja, Sijerinska Banja, Prolom Banja, Kursumlijska Banja, Lukovska Banja, Ribarska Banja, Sokobanja, Niska Banja and Zvonacka Banja. None of the spas has completely viewed bioclimatic analyses; therefore, it was of crucial importance to initiate the foundation of relevant bioclimatic analyses, in which, apart from a balneological image, the healing and therapeutaically recreational capacity of the places would be presented. The exploration of physically geographical features aims at answering the basic natural prerequisites that have caused thermo mineral phenomena, which has formed the basis for the formation of spas ,which over time have grown into settlements. This determines natural potentials, including their valorization, minding the course of correct management and environmental protection. The current information concerning spa prospects has been imprecise and unprofessional. Therefore, particular spas have been referred to as having healthy mountainous air or a specific wind source. In an attempt to complete the picture of the given spas potential, what is being exposed is the analysis of eco climatic and balneological features, its planning function, as well as the development of the places, which in time have become settlements. This entails a climatic element analysis and complex climatic relations. The work has analysed climatic elements : air temperature, air humidity, air pressure, winds , cloudiness and the permanance of sun rays in order to realise the basic climatic features of the places. What follows is the analysis of a complex climatic relation as to determine the basic climatic types, bio types and classes...

Ekonomsko-geografske i demografske promene agrarnog prostora Srbije

Changes of agrarian space in Serbia: economical-geographycal and demographycal aspects

Imajući na umu dinamiku poljoprivrednog i seoskog stanovništva, proces demografske tranzicije u Republici Srbiji (u daljem tekstu Srbiji) i tranziciju srpske ekonomije od primarnog sektora ka sektoru usluga, sa jedne strane, i od centralno-planske ka tržišnoj ekonomiji sa druge, ova teza nastoji da empirijski dokaže zaokret u izboru primarnog zanimanja seoskog stanovništva. U uslovima kada su direktne investicije u seosku ekonomiju veoma ograničene, a za razliku od perioda industrijalizacije šanse za nepoljoprivredno zapošljavanje seoskog stanovništva značajno redukovane, izbor primarnog zanimanja seoske populacije i diverzifikacija seoske ekonomije i prihoda oslonjena je na lične i lokalne resurse, materijalne ili ljudske, čije je puno angažovanje vezano za praksu samozapoljavanja i preduzetništva. U startegijama razvoja poljoprivrede a posebno u novijim strategijama ruralnog razvoja, netradicionalne poljoprivredne aktivnosti i novostvoreni nepoljoprivredni poslovi smatraju se ključnim faktorima održivog razvoja sela. Zato se u ovoj tezi savremene ekonomsko-geografske i demografske promene agrarnog prostora Srbije, istražuju sa stanovišta diverzifikacije ekonomskih aktivnosti i načina na koji diverzifikacija aktivnosti i prihoda može uticati na održiv demografski razvoj. Pretpostavlja se da je stanovništvo slabo urbanizovanog prostora Srbije, prepoznavši problem kontinuiranog slabljenje poljoprivrede, neizvesnih izvora prihoda i snažne emigracije, na izazove ekonomske globalizacije odgovorilo razvojem novih formi privređivanja. Takođe se pretpostavlja da diverzifikacija poljoprivrednih aktivnosti, multifunkcionalnost poljoprivrede i pluriaktivnost poljoprivrednog stanovništva doprinose usporavanju emigracije seoskog stanovništva. Više kvalitetnijih nepoljoprivrednih poslova u seoskim sredinama moglo bi usporiti po polu selektivno iseljavanje radno i reproduktivno sposobnog stanovništva, što je posebno važno u kontekstu redukovanja polnog debalansa u srpskim selima i kontekstu bračnosti i fertiliteta seoske populacije. Empirijsko istraživanje u ovoj tezi je utemeljeno na pretpostavci da više stope aktivnosti u nepoljoprivrednim delatnostima doprinose generisanju prihoda i unapređenju standarda života seoskog stanovništva, što je osnovna pretpostavka održivog ekonomskog i demografskog razvoja domaćinstava i seoskih naselja. Sa stanovništa delatnosti, istraživanje diverzifikacije poljoprivrede i nepoljoprivrednih aktivnosti seoskog stanovništva, fokusirano je na samozaposlene pojedince i domaćinstva uključene u preradu i trgovinu poljoprivrednim proizvodima, zatim na aktivne u prerađivačkoj industriji i posebno, na radnosposobno seosko stanovništvo koje je šansu za zaposlenje potražilo u sektoru usluga. Kako je najširi kontekst istraživanja ekonomskih i demografskih promena agrarnog prostora u Srbiji utemeljen na konceptu nove ekonomije i nove ruralne ekonomije, u tezi je, saglasno savremenim tendencijama opadanja uticaja distance na osnovu razvoja informaciono-komunikacionih tehnologija, sugerisana potreba redefinisanja mesta stanovnanja i mesta rada. Zato su istraživanjem obuhvaćeni samozaposleni preduzetnici koji posao obavljaju u okviru sopstvenog doma, gazdinstva ili domaćinstva, što je saglasno podsticajima samozapošljavanja i razvoja kućnih mikro preduzeća. Upravo ova dva fenomena nove ruralne ekonomije, samozapošljavanje i rast kućnog mikro-biznisa, dominantne su mera razvoja, revitalizacije i održivosti sela koje se predlažu u najvažnijim dokumentima ruralnog i lokalnog ekonomskog razvoja razvijenih zemalja. Stoga je bilo interesantno istražiti u kojoj su meri ove nove forme rada i netradicionalni poljoprivredni poslovi zastupljeni u selima Srbije, na koji način su uslovljeni sastavom seoskog stanovništva, i u kojoj meri doprinose održivom razvoju seoskih zajednica. Opšti cilj istraživanja je da na naučnim osnovama istraži uticaj koji na održiv ekonomski i demografski razvoj sela u Srbiji ima diverzifikacija seoske privrede i sa njom povezana praksa samozapošljavanja i kućnog preduzetništva. Poseban cilj disertacije je da objasni prirodu i opseg veza koje se novostvorenim nepoljoprivrednim poslovima ostvaruju između ruralnih i urbanih zajednica, posebno implikacije tih veza na ekonomsku i demografsku održivost seoskih domaćinstava. Teorijski okvir empirijskog istraživanja u ovoj tezi omogućila je kombinacija tri teorije: teorije održivog razvoja, fon Tinenova (von Thunen) teorija prostorne ekonomije (korišćenja poljoprivrednog zemljišta) i Porterova (Porter) teorija generičkih strategija konkurentnosti. Anketnim istraživanjem na stratifikovanom uzorku dobijeni su primarni izvori podataka koji su analizirani uz pomoć kvantitativnih i kvalitativnih tehnika. Glavni rezultati ove disertacije obuhvataju: veze koje diverzifikacija seoske privrede kreira u prostoru, posebno netradicionalne selo-grad veze gde su urbani rezidenti potrošači ruralnih usluga; prostorne varijacije demografskih karakteristika ruralnih preduzetnika i uticaj sastava seoskog stanovništva na izbor i održivost nepoljoprivrednih i netradicionalnih poljoprivrednih poslova; prostorne varijacije delatnosti i faktora koji utiču na izbor primarnog zanimanja; uticaj demografskih obeležja preduzetnika na selektivan izbor strategija kojima se jača konkurentnosti proizvoda i usluga i prostorne varijacije u doprinosu netradicionalnih seoskih poslova demografskoj i ekonomskoj održivosti domaćinstava i zajednica.

Having in mind the dynamics of agricultural and rural population, the process of demographic transition in Serbia, and the transition of Serbian economy from primary to service sector, on one side, and from central-planned to market economy on the other side, the aim of this thesis is to prove the shift in the primary occupation of rural population. In circumstances where direct investments in the rural economy are very limited, and unlike the period of industrialization the chances of non-agricultural employment of the rural population are significantly reduced, the choice of primary occupation of the rural population and the diversification of rural economy and incomes rely on personal and local resources, technical or human, whose full engagement is linked to practice of self- employment and entrepreneurship. In the strategies of agricultural development, especially newer strategies of rural development, untraditional agricultural activities and newly non-agricultural jobs are considered to be the main factors of sustainable development in villages. That is why this thesis studies modern economic-geographical and demographical changes of agrarian space in Serbia from the economy activities and incomes diversification standpoint. It is thought that the population of rural parts of Serbia recognized the problems that are decrease of agriculture, insecure income sources and strong emigrations towards urban parts of the country, and reacted to these globalization challenges by developing new forms of activity. It is also thought that the diversification of agricultural activities, the multi-functionality of agriculture and pluriactivity of agricultural population slow down the rural population emigrations. More non-agricultural jobs of higher quality in rural regions could slow down the gender-selective emigrations of the population capable of work and reproduction, which is especially important in the context of reducing gender gap in Serbian villages and in the context of marriage and fertility of rural population. Empirical research in this thesis is based on the hypothesis that higher rates of activity in the non-agricultural sectors can improve life standards and generate incomes in rural areas, which is the main hypothesis of sustainable development in households and rural villages. From the occupation standpoint, researches on the agricultural diversification and non-agricultural activities of the rural population focus on self-employed individuals and households involved in the proccesing and trading of agricultural goods, and especially on the work-capable rural population that searched their chance of employment in the service sector. This is why the research includes self-employed entrepreneurs that work in their own households. These two phenomenons of the new rural economy, self-employment and home micro-business expansion, are a sign of development, revitalization and rural sustainable development, that are suggested in the most important acts about rural and local economic development of developed countries. It was interesting to explore how these new forms of work and non-traditional agricultural jobs are spread in Serbian villages and does the structure of rural population set the conditions. The aim of the research is to explore the influence that rural economy diversification and the practice of self-employment have over the sustainability development. A special aim of this thesis is to explain the relations new non- agricultural jobs create between rural and urban communities, especially how these relations implicate on the economic and demographic sustainability of rural households. The theoretical point of the research in this thesis is based on the combination of three theories: theory of the sustainability development, theory of space economy (use of agricultural land) and theory of competitive strategy. Through questionnaire surveys, primary data were obtained and both qualitative andquantitative techniques were employed to analyze the data. The main result of the thesis included the relations that rural economy diversification creates in space, especially the non-traditional village-city relations where the urban residents are rural service spenders; space variations of demographic characteristics of rural entrepreneurs and the influence rural population structure has over the choice and sustainability of the non-agricultural and non-traditional agricultural jobs; space variations of occupations and factors that effect the choice of primary occupation; the influence gender has over the selective choice of competitive strategies; space variations of non-traditional rural jobs to demographic and economic sustainability of households and communities. The results have shown that entrepreneurship helps of rural communities in Serbia sustain, that non-agricultural jobs generate incomes and chances of employment of the local population, and that agricultural activities diversification supports the local community economy and effects the demographic development of rural population.

Modeli predikcije ishoda borbi vrhunskih takmičara u rvanju grčko-rimskim i slobodnim stilom

Models of fight outcome prediction for top athletes in greco-roman and freestyle wrestling

U retrospektivnoj eksplorativnoj studiji sa paralelnim grupama, na uzorku borbi rvača grčko-rimskim i slobodnim stilom (n=268), koji su nastupili na završnom olimpijskom turniru (OI London 2012.), ispitana je struktura prostora u kojem se odvija takmičarska aktivnost i utvrdjene su razlike izmedju subuzoraka formiranih pod kriterijumima stila, težinske kategorije i ishoda borbe. Svaki nastup takmičara bio je opisan sa 40 varijabli, u kojima su rezultati prikupljeni faktografskom metodom i analizom video zapisa borbe. Rezultati ukazuju da se takmičarska aktivnost u rvanju, bez obzira na disciplinu u kojoj rvači nastupaju, može posmatrati u jedinstvenom prostoru tehničko-taktičke aktivnosti, kojeg definiše pet latentnih dimenzija interpretiranih kao: takmičarska efikasnost, morfološke dimenzionalnosti, trajanje meča, sporne tehničko-taktičke aktivnosti tokom meča i povrede sportskih pravila u takmičarskoj aktivnosti. Upoređivanje subuzoraka prema težinskim kategorijama kod rvača grčko-rimskim stilom su konstatovane razlike u sedam, a kod rvača slobodnim stilom, u trinaest varijabli. Pobednici i poraženi u grčko-rimskom stilu razlikovali su se u osamnaest varijabli, dok su u slobodnom stilu ove razlike su bile značajne u četrnaest varijabli. Rezultati ukazuju da pobednike u grčko-rimskom stilu karakteriše takmičarska efikasnost u elementima odbrane i napada u parteru, dok pobednike u slobodnom stilu karakterišu elementi kojima se osvajaju bodovi u stojećem stavu, kao i u klinču. Uporedjivanje stilova u multivarijatnom modelu ukazuje da slobodni stil obiluje većom dinamikom i brojem izvedenih tehničko-taktičkih elemenata tokom borbe, u odnosu na grčko-rimski stil, u kojem više do izražaja dolaze morfološki pokazatelji. Metodom binarne logističke regresione analize formirani su modeli predikcije ishoda mečeva, koji su prikazali zavidne prediktivne sposobnosti. Od analiziranih varijabli najznačajniji doprinos pozitivnom ishodu meča u grčko-rimskom stilu, imalo su pokazatelji takmičarske efikasnosti u odbrani i napadu u parteru. Kod rvača slobodnim stilom najznačajniji doprinos je imala efikasnost izvodjenja tehnika u stojećem stavu, zatim osvajanje poena u klinču i na kraju efikasnost izvodjenja tehnika u parteru. mr Mladen Kecman - doktorska disertacija iii

In a retrospective exploratory study with parallel groups, on a fight sample of Greco-Roman and Freestyle wrestlers (n = 268), performing at the final Olympic tournament (London, 2012), the structure of the space in which the competitive activity occurred was examined and the differences between subsamples formed under the criteria of style, weight category and the fight outcome were determined. Each contestant's performance was described trough 40 variables, in which the results were collected using factographic method and analyzing the fight video records. The results indicate that the competitive activity in wrestling, regardless of the discipline in which the wrestlers perform, can be observed in the unique space of technical and tactical actions, which defines five latent dimensions interpreted as: competitive efficiency, morphological dimensionality, the duration of the match, disputed technical and tactical actions during the match and competition rules violations in sports activities. Comparing subsamples according to weight categories in Greco-Roman wrestlers differences were noted in seven, and in Freestyle wrestlers in thirteen variables. Winners and defeated in the Greco-Roman style differed in eighteen variables, while in Free style these differences were significant in fourteen variables. The results indicate that the winners in Greco-Roman style are characterized by competitive efficiency in the defense and the attack elements on the ground, while the winners in Free style are characterized by elements awarding points in the standing position, as well as in the clinch. Comparison of styles in the multivariate model indicates that the Freestyle abounds the greater dynamics and the number of implemented technical and tactical elements during the fight, in relation to the Greco-Roman style, in which morphological indicators are more manifested. Using binary logistic regression analysis method the match outcome predicting models were established showing remarkable predictive ability. Of the analyzed variables the most significant contribution to the positive outcome of the match in the Greco-Roman style had indicators of competitive efficiency in defense and attack on mr Mladen Kecman - doktorska disertacija v the ground. In Freestyle wrestlers the most significant contribution had the efficiency in performance techniques in a standing position, then conquer points in the clinch and eventually the effectiveness of performance techniques on the ground.

Regionalizacija kao determinanta prostornog razvoja Republike Srpske

Regionalization as a determinant of spatial development of Republic of Srpska

Predmet istraživanja ove doktorske disertacije jeste detrminisanje prostorne i funkcionalne organizacije u Republici Srpskoj...

The subject matter of this doctoral dissertation was the determination of spatial and functional organization in Republic of Srpska. The specificity of Republic of Srpska space, territorial forms, historical factors, and modern processes decided on the course of the research. Studies were conducted in order to set the level of development of spatial-functional connections and relations within the settlement network in Republic of Srpska, all in order to define the best-suitable model of future territorial development. Having used the principles of functional regionalization and all the relevant theoretical and methodological schemes of modern spatial planning, we set the sustainable model of the future development of Republic of Srpska. The primary goal of the study was the identification of all the significant indicators of space and their intensity and role within the total development process. Having analyzed the historical assumptions, physicalgeographical and social-economic foundations, and validity of settlement network development, we offered a scientific framework for potential future analyses, research, and approach to regionalization. Theoretical-methodological roots of the regional system study were based upon the paradigms of spatial organization focusing on nodal regionalism. The urban settlements are the bearers of development within a space, in which they either integrate or disintegrate one heterogeneous space. Hence, nodal and functional regions are formed. In time, there were four such regions formed completely naturally in Republic of Srpska and they were determined by the population distribution, function of public services, infrastructure, etc. The space targeted in this study is a newly-formed state, which originated under specific circumstances. In addition, it is one of the two entities within a joint state of Bosnia and Herzegovina. Apart from the two entities, there is the Brcko District that was given a special status by the Decision of International Court of Arbitration. Bosnia and Herzegovina Constitution defines certain domains but territorial organization is under the jurisdiction of the entities. One such multi-layer jurisdiction division determined the division of BiH Federation into ten cantons and seventy-nine municipalities. On the other hand, Republic of Srpska organization is characterized by both central and local authorities over sixty-four municipalities. The timeline covered by the analyticalstatistical research dates from 1992 onwards. It took twenty-two years to conduct a new official population census in Bosnia and Herzegovina the results of which are still unofficial. Hence, the analyses are based upon the data from the Republic of Srpska Institute of Statistics, i.e. upon our estimations. The following work hypotheses were reached upon the subject matter, goals, and tasks of the study: 1. Regionalization is the foundation of a high-quality spatial planning and a successful regional politics of Republic of Srpska. 2. Regionalization politics is of an utmost relevance for Republic of Srpska due to the country’s specific position of a BiH entity and the fore-coming process of EU accession. 3. The lack of regional organization and development at RS level imposes the necessity of an extensive and thorough study of the process that might offer adequate solutions.. Taking into account the available data and bibliography, our study focused on the analytic and synthetic methods. Firstly, a theoretical-methodological framework was set within which the research was conducted. Having analyzed the diachronic system development, we determined specific patterns of the analyzed space. The regional research was performed via the application of different science-based methods and models and EU-practiced methods and models on regional politics. The whole study targeted a coherent and sustainable regional development, and the total development of Republic of Srpska. This doctoral dissertation comprises several causal parts: the introduction, four chapters, and final reflections. There are personal conclusions and reflections provided after each part, and the following research was based upon the previous hypothesis. The conducted study undoubtedly confirmed the fact that over time there have been four nodal-functional regions formed in Republic of Srpska. In addition, we determined a range of shortcomings of the State-Municipality/City system, especially when it comes to a territory of a specific form. Thus, the development initiated from a single center (Banjaluka) under the given circumstances – especially with reference to bordering and distant municipalities – is virtually impossible. Furthermore, a conclusion was reached that the least developed municipalities were those that inherited the smallest portion of former BiH municipalities’ territory and lost the municipal centers. All the conducted research indicated a constant degradation and negative trends in the east Republic of Srpska, which was not the case with the western part of the country that has far better conditions for future development. To sum up, Republic of Srpska is a space within which there are four nodal-functional regions, i.e. Banjaluka, Doboj-Bijeljina, Sarajevo-Zvornik, and Trebinje-Foca. Banjaluka region is mono-polar with the city of Banjaluka as the dominant center. Other three regions are dominantly bipolar and have their centers in towns of Doboj, Bijeljina, Zvornik, East Sarajevo, Foca, and Trebinje. If the future development of Republic of Srpska is based upon the regional politics included in these four regions, we may expect positive effects within the total area.

Polno specifičan efekat fluoksetina na signalizaciju posredovanu glukokortikoidnim receptorom u hipokampusu pacova izlaganih hroničnom stresu izolacije

The gender-specific effect of fluoexetine on glucocorticoid receptor mediated signalization in the hippocampus of rats exposed to chronic isolation stress

Smatra se da je hronični stres jedan od glavnih etioloških faktora povezanih sa patofiziologijom mnogih psihijatrijskih poremećaja, uključujući depresiju. Iako je odgovor na stres ključan u odrţavanju homeostaze, maladaptivni odgovor moţe dovesti do povećanja faktora rizika koji dovode do razvoja bolesti. Tokom proteklih decenija brojne studije izvedene na depresivnim pacijentima kao i istraţivanja na ţivotinjskim modelima predloţile su nekoliko bioloških teorija koje su pokušale da objasne patogenezu depresivnih poremećaja uzrokovanih stresom. Jedan od najkonzistentnijih nalaza u ovim istraţivanjima jeste narušena aktivnost hipotalamo-hipofizno-adrenalne (HPA) ose, koja se odlikuje narušenom funkcijom glukokortikoidnog receptora (GR) pogotovu u hipokampusu, moţdanoj strukturi koja je najosetlijivija na stres. Kao posledica gore pomenutih činjenica sasvim je logično sto je GR isplivao kao meta novih antidepresivnih lekova. Osim pitanja molekularne osnove u patogenezi depresije, poslednjih godina sve veću paţnju privlači pitanje polnog dimorfizma u odgovoru na stres i adekvatnu terapiju, s obzirom to da epidemiološke studije ukazuju da su ţene podloţnije depresiji i da dva puta češće oboljevaju od iste. TakoĎe, brojne studije pokazuju i da ţene slabije odgovaraju na terapiju tricikličnim antidepresivima i da znatno bolji učinak kod ovog pola imaju antidepresivi iz klase selektivnih inhibitora ponovnog unosa serotonina (SSRI). Ipak, pored svih prikupljenih podataka molekularni mehanizmi koji leţe u osnovi ovih kliničkih nalaza, kao i molekularne osnove polnog dimorfizma u odgovoru na stres, uključujući glukokortikoide i signalizaciju posredovanu GR-om, još uvek nisu u potpunosti razjašnjeni. Pored glukokortikoida, vaţnu ulogu u regulaciji funkcije GR-a ima i njegova fosforilacija na specifičnim aminokiselinskim ostacima koja utiče na stabilnost samog receptora i njegovu translokaciju iz citoplazme u jedro, što dovodi do pojačane ili smanjene transkripcione aktivnosti samog GR-a, što sve zajedno utiče na vaţne ćelijske procese. Imajući u vidu vaţnost fosforilacije u regulaciji funkcije GR-a, kao i rezultate prethodno dobijene u našoj laboratoriji, u ovoj doktorskoj disertaciji ispitivan je polno-specifičan efekat hroničnog tretmana fluoksetina, antidepresiva iz klase SSRI, na ponašanje nalik depresivnom, na koncentraciju kortikosterona (KORT) u serumu, unutar ćelijsku distribuciju GR-a, kao i na fosfo-forme receptora na serinu 232 (pGR232), serinu 246 (pGR246) i treoninu 171 (pGR171) u hipokampusu ţenki i muţjaka pacova Wistar soja prethodno izloţenih stresu hronične socijalne izolacije...

Exposure to chronic stress has been associated with the pathophysiology of many psychiatric disorders including depression. Although, the stress response is essential for maintenance of homeostasis, maladaptive response to stress can elevate risk factors that lead to the disease. Several theories have been proposed to explain stress-related pathogenesis of depression, including impaired activity of hypothalamo-pituitary-adrenal (HPA) axis, which is one of the most consistent findings in assessing the depressive state in years of research. Notably, studies carried out in depressed patients, as well as studies on animal models of depression showed consistently dysfunctional limbic LHPA axis activity, leading to altered levels of circulating glucocorticoids. The activity of LHPA axis is controlled through inhibitory feedback mechanisms involving different brain structures with main research focus on hippocampus. At the molecular level, glucocorticoids exert their effects by activating the glucocorticoid receptor (GR), a key regulator of the negative feedback of the LHPA axis activity. Therefore taking into account above mentioned facts it is quite logical that GR emerged as a potential candidate for antidepressant action. Aside from investigating the molecular mechanisms that lie in the basis of depression, in recent years the question of gender-dimorphism is becoming more appealing and attracts more attention. Epidemiological studies demonstrate that women are more vulnerable to stress related psychopathologies than men, since depression occurs twice as frequently in women. Furthermore, women tend to show poorer response rates and slower clinical improvement with tricyclic antidepressants (TCAs) and appear to respond better to selective serotonin reuptake inhibitors (SSRIs). However the mechanisms underlying these clinical facts, as well as molecular specificities that underlie possible sex differences, including the GCs and GR signaling are not well defined. Besides glucocorticoids, the GR activity could be also controlled by specific modification via phosphorylation of GR on specific aminoacide residues that influence the stability of receptor and its translocation from cytoplasm to the nucleus which may lead to enhanced or diminished transcriptional activity of the GR, all together to affect multiple cellular processes...

Istorijskodemografske i etnodemografske osnove razvitka stanovništva Istočne Srbije

Historical demographic and ethno-demographic basics for the development of population of Eastern Serbia

Specifičnosti demografskog razvitka Istočne Srbije proizilaze iz jedinstvenosti depopulacionih procesa započetih još u drugoj polovini XIX veka, a rezultat su istorijskih zbivanja, autentičnog kulturno-istorijskog nasleđa i mentaliteta stanovništva koje ga naseljava. Današnji razmeštaj i etnička struktura stanovništva Istočne Srbije su rezultat snažnog delovanja migracionih kretanja u prošlosti, odnosno doseljavanja novih etničkih masa koje su u procesima adaptacije i asimilacije sa starosedelačkim stanovništvom dale nova socio-kulturna obeležja ovom delu Srbije. Istočna Srbija već više od jednog veka neprekidno gubi populacionu snagu. Uzroci depopulacije Istočne Srbije nisu jednostavni i jednoobrazni, i kreću se u širokom rasponu, između specifičnosti demografskog razvitka sa jedne strane, i činioca, intenziteta i pravaca društveno-istorijskog i socio- ekonomskog razvoja sa druge strane, kao i njihove međuzavisnosti i veza. Nepovoljni demografski procesi u Istočnoj Srbiji imaju svoju predistoriju i počeli su da se javljaju ranije nego što su evidentirani kao demografski problem, dok neki njihovi uzroci sežu u daleku prošlost, pa je neophodno i naučno opravdano da ih danas posmatramo dugoročno u onoj meri koliko nam to omogućavaju izvori podataka. Zato je cilj ovog rada utvrđivanje i naučno argumentovano objašnjenje etnodemografskih karakteristika i specifičnosti demografskog razvitka Istočne Srbije. U tom smislu, glavni zadaci istraživanja su razmatranje istorijskog nasleđa i savremenih problema demografskog razvitka, naučno sagledavanje demografskih i nedemografskih uticaja na uspostavljanje i formiranje demografskih trendova i tokova demografske tranzicije, vremensko datiranje i prostorno determinisanje pojava i posledica biološke depopulacije, ustanovljavanje faza, stadijuma i posledica demografskog starenja, kao i naučna analiza međuzavisnosti razvitka stanovništva i prostora na kome je ono nastanjeno. Značajno mesto u etnodemografskim istraživanjima Istočne Srbije zauzima proučavanje porekla, brojnosti, razmeštaja, i opšte uloge vlaškog stanovništva u procesu ukupnog demografskog razvitka. U popisima stanovništva Srbije se prati broj Vlaha još od 1866. godine, kada su činili oko 10% od ukunnog stanovništva, ali etnostatistički podaci potvrđuju da su Vlasi etnička zajednica izrazito flotantnog ponašanja pri nacionalnom deklarisanju što uzrokuje otežano dobijanje kvalitetnih statističkih podataka koji su neophodni za praćenje demografskih pojava i procesa, ne samo vlaškog, nego i ukupnog stanovništva Istočne Srbije. Etnička simbioza Srba i Vlaha u Istočnoj Srbiji koja se odvijala prema potrebama i shvatanjima stanovništva je neraskidivo povezana sa zajedničkom prošlošću, a međusobno povezivanje stanovništva nije samo potvrđivano rodbinskim vezama već i kroz sve druge oblike svakodnevnog života što je doprinelo stvaranju posebnog osećanja pripadništva Vlaha većinskoj srpskoj etničkoj zajednici na koje ukazuju i statistički podaci. Nepoklapanje stvarnog i deklarisanog etničkog identiteta predstavlja ključni problem u etnodemografskim istraživanjima, međutim zvanična etnostatistička slika se mora prihvatiti kao istorijska, politička i demografska realnost, prema kojoj smo se u našim opservacijama i analizama odnosili kao prema zvanično utvrđenoj činjenici. Proces demografskog razvitka Istočne Srbije tokom XIX i XX veka obeležen je pojavom biološke depopulacije još od druge polovine XIX veka, što je označilo i početak demografske tranzicije, odnosno tranzicije reprodukcije i prihvatanja kontrole rađanja. Objašnjenje za ranu pojavu biološke depopulacije u Istočnoj Srbiji je moguće pronaći u određenim socio-kulturnim pojavama koje su se manifestovale kontrolom rađanja i uvođenjem tzv. ''sistema jednog deteta'', a pad nataliteta i prirodnog priraštaja u XIX veku najpre je otpočeo u okruzima u kojima je koncetrisano vlaško stanovništvo. Tokom druge polovine HH i početkom XXI veka prirodni priraštaj stanovništva Istočne Srbije je imao opadajući trend, a negativna vrednost je prvi put zabeležena 1978. godine, znatno ranije u odnosu na druge delove Srbije. Etnička struktura opština u kojima je najranije zabeležen negativan prirodni priraštaj ukazuje na etnodemografski karakter biološke depopulacije, a izrazito nepovoljna starosna struktura, kao i odmakli proces demografskog starenja predstavljaju osnovne odlike najvećeg broja opština, a posebno onih u kojima je koncentrisano vlaško stanovništvo. Istočnu Srbiju karakteriše izrazito nizak nivo urbanizacije, koji je naročito izražen u opštinama u kojima je zastupljeno vlaško stanovništvo, a sva naselja u Istočnoj Srbiji u kojima Vlasi čine apsolutnu ili relativnu većinu spadaju u kategoriju ''ostala'', odnosno seoska. Iako je zahvaljujući svom geografskom položaju stanovništvo Istočne Srbije tokom svoje istorije najvećim delom ostalo izvan glavnih tokova modernizacije i društvene transformacije, ono je bilo suočeno sa važnim demografskim i drugim promenama koje su već s kraja XIX veka formirale okvir i postavile osnove za izlazak iz tradicionalne, i ulazak u savremenu fazu demografskog razvitka koja je karakteristična za današnja razvijena društva. Promene koje su registrovane u komponentama populacione dinamike nisu bile iste po intenzitetu i smeru u svim delovima posmatrane geografske oblasti, i direktno su zavisile od više neposrednih i posrednih faktora koji su bili rezultat dinamičnih istorijskih okolnosti, ali i specifičnog kulturno- civilizacijskog nasleđa koje se i danas ispoljava nizom autentičnih socio- kulturnih fenomena.

Specifics of the demographic development of Eastern Serbia arise from the uniqueness of the depopulation process that began in the second half of the 19th century, and are the result of historical events, authentic cultural and historical heritage and mentality of the population that inhabits it. Today distribution and ethnic structure of Eastern Serbia are the result of strong effects of the migratory movements in the past, as well as immigrations of new ethnic groups, that in the process of adaptation and assimilation with indigenous population, were gave the new anthropological and socio- cultural features of this part of Serbia. The Eastern Serbia steadily losing population power more than a century. The causes of the depopulation in Eastern Serbia are not simple and uniform, ranging over a wide range, between specific demographic development on the one hand, and the factors, the intensity and directions of socio-historical and socio-economic development on the other hand, as well as their interdependencies and relationships. Unfavourable demographics in Eastern Serbia have a prehistory and began to appear, before they were recognized as a demographic problem. Some of the causes date back into the past, so it is necessary and scientifically justifiable long term observation, to the extent that we are allowed by the data sources. Therefore, the aim of this paper is to determine and scientific explain ethno-demographic characteristics and specific of demographic development of Eastern Serbia. In this context, the main objectives of the study were: review of historical heritage and contemporary problems of demographic development, scientific analysis of demographic and non-demographic impact on demographic trends and the establishment of demographic transition, temporal and the spatial determination of phenomena and consequences of biological depopulation, the establishment phases and the consequences of demographic aging, and scientific analysis of the interdependence of population development and the area that inhabits it. Ethno-demographic research of Eastern Serbian include and the study of the origin, number, disposition, and general role of the Vlach population in the overall population development. Although the Vlach population was included in censuses since 1866, when accounted for 10% of the total population, the ethno-statistical data confirm the highly floating behaviour of Vlach population in censuses, causing difficulty obtaining the quality statistical data necessary for monitoring demographic phenomena and processes, not just Vlach population, but the total population of Eastern Serbia. The ethnic symbiosis of Serbs and Vlach population in Eastern Serbia, which took place according to the needs and beliefs of the population, is unbreakable linked to the common past. Interconnection of population was created, not only by family ties but all the other forms of everyday life, contributing to the creation of a special feeling of belonging Vlach population to majority Serbian ethnic community, as reflected in statistics. Discrepancy between real and the declared ethnic identity is a key problem in ethno- demographic research. However, the official ethnic structure should be accepted as historical, political, and demographic reality, which we will treat as formally established state of facts in our further observations and analyzes. During the 19th and 20th century the process of demographic development of Eastern Serbia was marked by the advent of biological depopulation since the second half of the nineteenth century, which marked the beginning of the demographic transition, and transition of reproduction and acceptance of birth control. The explanation for the early appearance of biological depopulation of Eastern Serbia can be found in certain socio- cultural phenomena manifested by birth control and application of ''one child system''. Declining of birth rate and natural growth in the nineteenth century began early in the districts where the Vlach population was most concentrated. During the second half of XX and beginning of XXI century, natural growth of Eeastern Serbia declined, a negative value was recorded in 1978, much earlier than in other parts of Serbia. The ethnic structure of the municipalities with the earliest negative natural growth indicates to the ethno-demographic character of biological depopulation, and the extremely unfavourable age structure and faster process of demographic aging are the main features of the municipalities where the Vlach population was most concentrated. Eastern Serbia is characterized by extremely low level of urbanization, which is particularly announced in municipalities where the present Vlach population. All villages in eastern Serbia where Vlachs are an absolute or relative majority belong to the category of ''other'' (rural). Although, due to its geographical location, the population of Eastern Serbia largest part of their history was beyond most important trends of modernization and social transformation, it was exposed to the important demographic and other changes, which formed the framework in the late 19th century, and establish the basis for getting out of traditional and entry into the contemporary stage of demographic development, which is characteristic of today developed societies. The changes that have been registered in the components of population dynamics were not the same in intensity and direction in all parts of the observed geographic areas; they were directly dependent on several direct and indirect factors that are the result of dynamic historical context, and the specific cultural and civilization heritage, whose are also manifesting today by series of authentic socio- cultural phenomena.

Dejstvo oksitocina na simpatoadrenomedularni sistem i srce pacova hronično izlaganih stresu izolacije

Effects of oxytocin on sympathoadrenomedullary system and heart of chronically isolated rats

Uvod: Simpatoadrenomedularni sistem predstavlja jedan od glavnih sistema uključenih u odgovor organizma na stres, reagujući na stres povećanim oslobađanjem kateholamina. Odsustvo interakcije između jedinki iste vrste, kao izvor stresa, dovodi do aktivacije simpatoadrenomedularnog sistema. Stoga je hronična socijalna izolacija već duže vreme prepoznata kao faktor rizika koji povećava stopu srčanih oboljenja. Oksitocin (OXT) predstavlja deo sistema koji koordinira odgovor organizma na stres a njegova kardioprotektivna uloga je predmet sve većeg broja studija. Materijal i metode: Mužjaci Wistar soja pacova su podvrgnuti hroničnoj socijalnoj izolaciji u trajanju od 12 nedelja. Poslednje dve nedelje životinje su tretirane OXT (3.6µg/100g s.c). Parametri ponašanja životinja su praćeni u testu otvorenog polja. Radioenzimskom metodom je utvrđivana koncentracija adrenalina (ADR) i noradrenalina (NA) u plazmi i ispitivanim tkivima. HE bojenjem i diferencijalnim tkivnim bojenjem su praćene histološke promene na nivou komora. Real-time PCR i/ili Wester blot metodom su praćene promene u nivou ekspresije gena za tirozin hidroksilazu (TH), noradrenalinski transporter (NET) i vezikularno monoaminski transporter 2 (VMAT2) kao i za beta3-adrenalinski (β3-AR) i muskarinski M2 receptor (M2 MR) i inducibilnu azot-oksid sintetazu (iNOS) u ispitivanim tkivima. Rezultati: Stres socijalne izolacije je doveo do povećane količine ADR i NA u plazmi, dok u srži nadbubrežne žlezde deluje na sintezu i skladištenje kateholamina, povećavajući nivo TH enzima i VMAT2. Hronična socijalna izolacija je dovela i do asimetrije u aktivnosti leve i desne stelatne ganglije povećavajući nivo ekspresije gena za TH i NET u desnoj stelatnoj gangliji. U levoj pretkomori i levoj komori je pokazano povećanje nivoa NA a utvđeno je i povećanje nivoa M2 MR u levoj i desnoj pretkomori kod socijalno izolovanih životinja. Stres je doveo i do povećanja iNOS proteina i veličine kardiomiocita u levoj komori. Tretman OXT u trajanju od 14 dana je pokazao anksiolitičko dejstvo u testu otvorenog polja, a doveo je i do smanjenja količine ADR i NA u plazmi socijalno izolovanih životinja. Oksitocin je uticao na povećanje preuzimanja i skladištenja kateholamina u srži nadbubrežne žlezde, dok je doveo do smanjene sinteze u desnoj stelatnoj gangliji. U levoj pretkomori je došlo do povećanja nivoa NET proteina usled tretmana OXT. U obe pretkomore tretman OXT je povećao nivo β3-AR, dok je u levoj komori doveo do povećanja nivoa M2 MR receptora. Oksitocin utiče na smanjenje veličine kardiomiocita u levoj komori socijalno izolovanih životinja. Zaključak: OXT u uslovima stresa pospešuje procese preuzimanja i skladištenja kateholamina u srži nadbubrežne žlezde, dok je u desnoj stelatnoj gangliji smanjio povećanu simpatičku aktivnost u uslovima stresa. Svoju glavnu kardioprotektivnu ulogu u srcu ispoljava delovanjem na kardioinhibitorne receptore, a ima i izraženo dejstvo u smanjenju hipertrofije nastale usled hronične izloženosti socijalnoj izolaciji. Sve ovo navodi na zaključak da je OXT deo sistema koji u uslovima stresa pomaže u uspostavljenu narušene homeostaze.

Introduction: The sympathoadrenomedullary system represents one of the major mechanisms involved in the body's response to stress, reacting to stress by increasing the release of catecholamines. The absence of interaction between individuals of the same species, as the source of stress, leading to the activation of symphatoadrenomedullary system. For this reason the chronic social isolation has long been recognized as a risk factor that increases the rate of heart disease. Oxytocin (OXT) is part of a system that coordinates the body's response to stress and its cardioprotective role remains the subject of a growing number of studies. Material and methods: Male Wistar rats were subjected to chronic social isolation for a period of 12 weeks. The animals were treated with OXT (3.6μg /100 g s.c.) for the last two weeks of social isolation. The behavioral parameters of animals were monitored by application of an open field test. The radioenzymatic method was used to determine the concentration of adrenaline (ADR) and noradrenaline (NA) in the plasma and tissue samples. HE staining and differential tissue staining were used to observe histologically changes in the ventricles. Real-time PCR and / or Wester blot methods were used for monitoring the level of gene expression of tyrosine hydroxylase (TH), noradrenaline transporter (NET) and the vesicular monoamine transporter 2 (VMAT2) and the beta3-adrenergic (β3-AR), the muscarinic M2 receptor (M2 MR) and inducible nitric oxide synthase (iNOS) in the examined tissues. Results: The social isolation has led to an increase in ADR and NA plasma levels, while in the adrenal medulla enhanced synthesis and storage of catecholamines, by increasing the level of TH enzymes and VMAT2. The chronic social isolation has led to the asymmetry in activities of the left and right stellate ganglia by increasing the level of gene expression of TH and NET in the right stellate ganglia. In the left atrium and the left ventricle social isolation has been shown to increase NA content and increase the level of M2 MR in the left and right atrium. The stress led to an increase in iNOS protein and size of cardiomyocytes in the left ventricle. The treatment with OXT for a period of 14 days showed anxiolytic effects in the open field test, and led to a decline of ADR and NA plasma levels of socially isolated animals. The oxytocin treatment led to an increased capacity of catecholamine uptake and storage in the adrenal medulla, while at the same time resulting in reduced synthesis in the right stellate ganglia. There was an increase in the left atrium in the level of the NET protein due to the OXT treatment. In both, atria OXT treatment has increased the level of β3-AR, while in the left ventricle has led to increased levels in M2 MR receptors. The oxytocin has affected the reduction in size of cardiomyocytes in the left ventricle of socially isolated animals. Conclusion: The OXT treatment under stress enchaces the uptake and storage of catecholamines in the adrenal medulla, while in the right stellate ganglia reduces the increased sympathetic activity under stress. The main cardioprotective role of OXT in heart is to exert action on cardioinhibotory receptors and OXT has a pronounced effect in reducing hypertrophy caused by chronic exposure to social isolation. All this suggests that the OXT is a part of the system which helps maintaining homeostasis under stress.

Ponašanja centrično pritisnutih elemenata složenog poprečnog preseka od nerđajućih čelika

Behaviour of built-up stainless steel members subjected to axial compression

Iako je 2013. godine obeležena stogodišnjica pronalaska nerđajućeg čelika, njegova značajnija primena u građevinarstvu započinje tek početkom ovog veka. Austenitni nerđajući čelik odlikuje niz specifičnosti koje opravdavaju njegovu primenu u konstrukcijama posebne namene: postojanost i visoka otpornost na dejstvo korozije, značajan kapacitet plastifikacije i izražena duktilnost, poboljšanje svojstava materijala uticajem hladne deformacije, postojanost na visokim i niskim temperaturama, superiornost površinskog izgleda bez zaštitnih premaza, neškodljivost po okolinu. Najveći ograničavajući faktor za njegovu masovniju primenu je visoka jedinična cena, ali i nepotpunost tehničke regulative koja, još uvek, ne sagledava na odgovarajući način specifičnosti ovog materijala. Cilj istraživanja koje je prikazano u ovoj doktorskoj disertaciji je omogućavanje šire primene nerđajućeg čelika u konvencionalnim konstrukcijama kroz detaljnu analizu ponašanja centrično pritisnutih, hladnooblikovanih elemenata višedelnog preseka. Osnovni materijal primenjen u okviru istraživanja je nerđajući čelik austenitne mikrostrukture sa oznakom 1.4301. Predmet istraživanja su višedelni elementi formirani od dva C profila koji su međusobno direktno povezani šavovima ili zavrtnjevima. Eksperimentalnim ispitivanjem su obuhvaćene skoro sve osobenosti u ponašanju pritisnutih elemenata: ispitana su mehanička svojstva materijala, sagledan nivo asimetrije i anizotropije materijala, sagledan uticaj hladnog oblikovanja na poboljšanje mehaničkih svojstava materijala, utvrđen kapacitet nosivosti poprečnog preseka, izmerene početne geometrijske imperfekcije i određena nosivost elemenata na fleksiono izvijanje oko nematerijalne ose. Napredni numerički modeli na bazi metode konačnih elemenata su napravljeni da simuliraju ispitivanje pri fleksionom izvijanju a kalibrisani su na osnovu eksperimentalnih rezultata. Korištena je kvazi-statička analiza primenom eksplicitnog dinamičkog solvera softverskog paketa Abaqus. Ovako kalibrisani modeli na bazi MKE korišćeni su dalje za parametarsku analizu. Cilj parametarske iii analize je da identifikuje uticaj pojedinih parametara na graničnu nosivost elementa. Razmatrani su parametri: vitkost elementa višedelnog preseka oko slabije, nematerijalne ose, vitkost samostalnog elementa u ravni višedelnog preseka, vrsta spoja između samostalnih elemenata, oblik i veličina početne geometrijske imperfekcije elementa. Na osnovu rezultata eksperimenata i numeričke analize, polazeći od preporuka datih u postojećim evropskim propisima za nerđajući i ugljenični čelik, definisane su preporuke za proračun nosivosti elemenata višedelnog poprečnog preseka sa blisko postavljenim samostalnim elementima. Preporuke su definisane u zavisnosti od vrste spoja između samosatalnih elemenata, po analogiji sa rezultatima sličnih istraživanja na ekvivalentnim elementima od ugljeničnog čelika. Obzirom, da ne postoje dostupni rezultati sličnih eksperimentalnih istraživanja gde je za materijal primenjen nerđajući čelik, preporuke su potvrđene poređenjem sa rezultatima sopstvenog eksperimentalnog ispitivanja.

Although the centenary of the invention of stainless steel was celebrated in 2013, its more significant implementation in construction industry was not established until the beginning of this century. Austenitic stainless steel is characterized by a number of features which justify its use in construction for special purposes: durability and corrosion endurance, high plastification capacity and ductility, improved characteristics of materials when subjected to deformation, resistance to high and low temperatures, superior surface appearance without protective coating, environmental safety. The main limiting factor for its wider application is the high unit price, as well as the incompleteness of technical regulations which are not taking into account properly all the specifics of this material. The purpose of the research presented in this doctoral dissertation is to enable wider application of stainless steel in conventional structures through detailed analysis of the behaviour of cold-formed built-up compression members. The base material used in this research is austenitic stainless steel grade 1.4301. Object research are built-up members composed of two C sections in contact, connected by weld or bolts. Experimental works included all the major behaviour characteristics of the compression member: mechanical properties of the material were measured, the level of asymmetry and material anisotropy was assessed, as well as the effects of the process of cold forming on improvement of the mechanical properties of the materials. Initial geometric imperfections, ultimate resistance of cross-section, ultimate resistance members to the flexural buckling around intangible axis, were also considered in experimental works. Advanced numerical models based on the finite element method were built to simulate behaviour under flexural buckling and they were calibrated with respect to the experiment data. Quasi-static analysis with the explicit dynamic solver software package Abaqus was engaged for the buckling analysis. Previously calibrated FEA models were further used for the parametric study. Purpose of the v parametric study was to identify the impact of parameters relevant to the ultimate resistance of the compression members. The considered parametres were: slenderness of the chord around intangible axis, slenderness of single member in the plane of built-up section, type of connection between the single member, initial geometric imperfections. Based on the experiments, as well as the numeric results and recommendations of the existing Eurocodes for stainless and carbon steel, the recommendations for calculation of the buckling resistance of bulit-up cross- section elements with chords in contact were defined. The recommendations were defined depending on the type of connection between the chords, according to the analogy with results of similar studies performed on the equivalent carbon steel members. Since there are no available experimental results of similar studies with stainless steel members, recommendations were verifed by comparing to the results of our own experimental works.

Održivi razvoj zaštićenog ruralnog prostora Srbije

Sustainаble development of protected rural area of Serbia

Održivi razvoj zaštićenog ruralnog prostora Srbije, odnosno administrativnih teritorija naselja koje pripadaju njihovom geoprostornom obuhvatu, podrazumeva integraciju niza fundamentalnih i aplikativnih problema i ciljeva, karakterističnih kako po naučnoj složenosti i značaju, tako i po rastućoj društvenoj aktuelnosti. Geoprostorni okvir istraživanja odnosi se na naučno i empirijski zahtevnu, integralnu, nešematizovanu, izazovnu i društveno korisnu problematiku. Fundamentalne (životna sredina, geoekologija, antropogeografija i dr.) i aplikativne (zaštita prirode, održivi razvoj, prostorno planiranje, praksa društvenog razvoja, GIS i dr.) discipline savremene nauke o životnoj sredini odredile su multidisciplinarni karakter teme disertacije. Izradu disertacije je pratio kontinuitet transformacije i ekspanzije epistemiološko/ontoloških i teorijsko/aplikativnih svojstava nauke o životnoj sredini i njenih temeljnih disciplina, ali i normativno planske prakse zaštite prostora. Primenjeni pristup percepcije sistema „zaštićeni predeli – ruralni prostor – održivi razvoj“ je proširen i na pozicije antropocentrizma (paradigma ljudske izuzetnosti) kao determinante vrednosti geoprostora. Antropocentrični pristup pored značaja izvorne prirode, podrazumeva i vrednost tradicionalnih i ekološki prihvatljivih privrednih, naseobinskih, demografskih i drugih potencijala. Zato su umesto zaštite u duhu ekologizacije i konzervacije, predloženi poželjni oblici i mehanizmi održivog, odnosno usmeravanog i kontrolisanog, razvoja sa zadržavanjem principa konsekventnosti – težišta na specifičnim vrednostima pojedinačnih zaštićenih teritorija. Ovakvo shvatanje održivosti po prirodi je blisko geografima, geografima zaštite životne sredine, socijalnim ekolozima, turizmolozima, prostornim planerima, demografima, ekonomistima i drugo. Polazeći od hipoteze da ekološka ograničenja koja su usmerena na ruralna naselja ne remete mogućnosti za njihov razvoj i ne ugrožavaju egzistencijalnu sigurnost stanovništva, u radu je predložen ekološko-geografski pristup upravljanja životnom sredinom u ruralnim naseljima čiji atari delimično ili u celini pripadaju zaštićenim prostorima u Republici Srbiji. Istraživanja su dokazala da zaštićeni prostor Srbije karakteriše predimenzionirana formalna, odnosno normativno-planska, a istovremeno de facto nefunkcionalna ekološka zaštita. Dugotrajni efekti ovakvog stanja su često degradirali retke i vredne elemente prirode, kao motive zaštite i uvećali razvojne disproporcije na teritoriji Srbije. Empirijska istraživanja ukazuju da su proteklih decenija opstali brojni nasleđeni i generisani novi problemi ekološkog i socioekonomskog statusa zaštićenog ruralnog prostora Srbije. Kumulativni efekti ovih procesa na lokalnom nivou su poodmakla ekološka degradacija i negativni naseobinsko-demografski trendovi, čime se na regionalnom i nacionalnom nivou produbljuju i usložnjavaju razvojni problemi. Nasuprot tome, predloženi model održivog razvoja zaštićenih II ruralnih prostora Srbije daje doprinos uvećanju racionalnog i ekološki opravdanog valorizovanja nacionalne teritorije i ukupnih razvojnih potencijala. Takvim postupanjem, njihov održivi razvoj, bi odgovarajućim upravljačkim mehanizmima smanjio dosadašnje razvojno zaostajanje, a povećao sposobnost lokalnih zajednica u pravcu racionalnog i svrsishodnog korišćenja resursa sa krajnjim ciljem njihovog očuvanja. Do sada usvojeni planski dokumenti u Srbiji ne bave se eksplicitno održivim razvojem ruralnih naselja u prostornom obuhvatu zaštićenih područja. U tom smislu neophodnost izrade novih dokumenata predstavljala bi osnov za adekvatno upravljanje zaštićenim teritorijama. Time bi se omogućilo pronalaženje rešenja za opstanak i revitalizaciju naselja i veće razvojne mogućnosti. Efekti tranzicije društva, a pre svega tržišno privređivanje kao decen- tralizovan i privatizujući model razvoja, manifestovali su se u nerealnom vrednovanju ekoloških usluga i zaštite prostora. Zbog toga je bilo neophodno istražiti mehanizme i pokrenuti inicijativu za redefinisanje međusobnog od- nosa i ukupne ekološke i socijalne uloge zaštićenog ruralnog prostora Srbije. Ovakva polazišta su u daljim razmatranjima implicirala da ruralne prostore ne treba posmatrati i tretirati samo kao delove (elemente) posebno vrednih i značajnih teritorija koje su u funkciji zaštite, što je često potenciran pristup, već kao njihov razvojni potencijal. Predstavljena polazišta, analize, rezultati i predloženi modeli ukazuju da je disertacija imala dva prostorna i problemska opsega – da dâ rešenja za empirijske probleme lokalnog i teorijske regionalnog karaktera. Dobijeni rezultati mogu poslužiti kao osnova za buduće istraživačke radove, sa ciljem kompleksnije analize i provere pravaca i mogućnosti održivog razvoja zaštićenih ruralnih prostora Srbije. Takođe, dat je pokušaj da rezultati rada budu i praktično korisni. Navedeno dobija na značaju time što su ova pitanja uzeta u razmatranje u, po njih, kriznom vremenu u kome se kriza ne manifestuje samo nagomilanim problemima, već i akutnom oskudicom ideja i sredstava za njihovo istraživanje i rešavanje.

Sustainable development of the protected rural area of Serbia, or belonging settlements and administrative territories, implies the integration of a range of fundamental and applied problems and objectives, characteristic as per scientific complexity and social importance, so the growing topicality as well. Problem-solving and spatial framework of the research is motivated by the perception of this issue as a scientifically and empirically demanding, integrated, non-schematic, challenging and socially useful. Also, with the conviction that the theoretical and methodological assumptions of modern science on the environment – its fundamental (environment, geoecology, anthropogeography and others), and applicational (nature protection, sustainable development, urban planning, practice of social development, GIS and others) disciplines, it is possible to solve this multi-disciplinary oriented subject. Writing of the thesis is followed by the continuity of transformation and expansion of the epistemological/ontological and theoretical/applicational properties as the environmental science and its core disciplines, so as the normative planning practice of the protection of space. The applied approach of the perception of system „protected landscape areas – rural areas – sustainable development“ has been extended to the position of anthropocentrism (the paradigm of human excellence) as a determinant value of geospace. The anthropocentric approach, in addition to the importance of original nature, also implies the value of traditional and environmentally friendly economic, settlement, demographic and other potentials. That is why, instead of protection in the spirit of ecology and conservation, the preferred forms and mechanisms of sustainable, that is channeled and controlled, development have been proposed with holding the consistency principle – focus on specific values of individual protected territories. This view of the sustainability, by nature, is close to geographers, environmental geographers, social ecologists, tourism experts, spatial planners, demographers, economists and others. Starting from the hypothesis that environmental restrictions aimed at rural areas do not harm the opportunities for their development and do not threaten existential security of the population, an ecological-geographic approach of environmental management in rural areas whose territories partially or completely belong to the protected areas in the Republic of Serbia, was proposed in dissertation. The researches have shown that current models of the protected rural areas management are characterized by exaggerated formal, or normative-planning, and at the same time de facto dysfunctional environmental protection. Long-term effects of this situation have often degraded rare and valuable elements of nature as motives of protection and enlarged developmental disproportions in the territory of Serbia. The empirical researches of diverse and representative model systems clearly show that, in the past, the numerous inherited and generated new negative effects of the importance for the environmental and socio-economic status of the protected rural areas of Serbia have survived. IV The cumulative effects of the above mentioned processes (at the local level) are well advanced environmental degradation and economic and settlement-demographic devastation of these areas, which at the regional and national level encourage the deepening and complexity of development issues. In contrast, the proposed model of sustainable development of the protected rural areas of Serbia contributes to enlargement of rational and environmentally justified valorization of the national territory and the total development potentials. By a such practice, their sustainable development, would, by the mechanisms of the desired direction and control (by type and intensity), reduce current developmental delay and poverty level, and increase the ability of local communities towards a rational and purposeful use of resources with the ultimate objective of their preservation. So far adopted planning documents in Serbia do not explicitly deal with sustainable development of the rural areas in spatial coverage of the protected areas. In this sense, the necessity of making this type of documents would represent the starting point for the proper management of these territories in the direction of finding a solution that would allow the survival of the settlements, and which revitalization would contribute to major development opportunities of the protected area. The market economy as decentralized and privatizing model of development and other effects of the transition of society, were reflected in unrealistic valuation of environmental services and protection of space. Therefore, it was necessary to investigate the mechanisms and move the initiative in the direction of redefition of the mutual relation and total ecological and social role of the protected rural areas of Serbia. Such starting points in further considerations imply that these areas should not be observed and treated only as parts (elements) of particularly valuable and important territories in the function of protection, which is often accentuated approach, but as potentially significant development projects. The presented starting points, analyses, results and proposed models suggest that the thesis had two spatial and problem solutions – in order to give the solution for the empirical issues of the local scope and theoretical issues of regional and global scope. The results can serve as a basis for future research papers, with the aim of a more complex analysis and verification of directions and opportunities for sustainable development of the protected rural areas of Serbia. This paper presents an attempt to answer another request – basic axiological assumption that its results are practically useful as well. The above mentioned gains importance in the way that these issues are taken into consideration in, for them, time of crisis, in which the crisis is not only manifested by accumulated problems, but also acute shortage of ideas and resources for their research and solving.

Povezanost fosforilacionog statusa glukokortikoidnog receptora i ponašanja pacova oba pola u neuroinflamatornom modelu depresije

The association of glucocorticoid receptor phosphorylation status and behavior of rats of both sexes in neuroinflammatory model of depression

Medijatori inflamacije imaju značajnu ulogu u patogenezi depresije. Jedan od načina na koje inflamacija utiče na nastanak ovog oboljenja jeste putem uticaja na hipotalamo-hipofizno-nadbubrežnu (HPA) osu i krajnje produkate aktivnosti ove ose, glukokortikoide. Glukokortikoidi se u ćelijama vezuju za glukokortikoidni receptor (GR), ligand-zavisan transkripcioni faktor, koji nakon vezivanja glukokortikoida prelazi iz citoplazme u jedro i mitohondrije, gde reguliše ekspresiju velikog broja gena. Aktivnost GR-a je regulisana i kompleksnim obrascem fosforilacija koje mogu da utiču na transkripcionu aktivnost ovog receptora. Pored toga što modulišu ekspresiju jedarnih gena, GR i njegove fosfoforme utiču i na mitohondrijske procese, i na taj način mogu da budu uključeni u proces apoptoze. Značajnu ulogu u nastanku ovog oboljenja ima i pol – kod žena se depresija javlja duplo češće nego kod muškaraca. Uzimajući u obzir navedene podatke, u ovoj tezi je ispitan uticaj sedmodnevnog tretmana inflamatornim agensom, lipopolisaharidom (LPS), na nivoe i fosforilacioni status GR-a u citosolu, jedru i mitohondrijama prefrontalnog korteksa (PFC) i hipokampusa mužjaka i ženki pacova Wistar soja koji pokazuju depresivno ponašanje. Takođe, u citosolu i jedru su praćeni i nivoi košaperona GR-a i kinaza uključenih u njegovu forforilaciju, dok su u citosolu i mitohondrijama praćeni nivoi nekoliko kaspaza i članova BCL-2 proteinske porodice uključenih u regulaciju apoptoze. Dalje, kako bi se utvrdili efekti promena u fosforilaciji na gensku ekspresiju, praćeni su i nivoi iRNK nekoliko jedarnih i mitohondrijskih gena koji su regulisani ovim receptorom i koji su uključeni u parofiziologiju depresije. Rezultati ove studije su pokazali da promene uočene u glukokortikoidnoj signalizaciji izazvane LPS-om utiču na procese uključene u nastanak depresije na tkivno- i polno- specifičan način. Kod mužjaka, poremećaji u glukokortikoidnoj signalizaciji su bili praćeni promenama koje ukazuju na smanjenu neuroplastičnost i neuroinflamaciju i povišenu oksidativnu fosforilaciju u PFC-u. Sa druge strane, promene u glukokortikoidnoj signalizaciji u hipokampusu su bile praćene promenama koje ukazuju na poremećenu serotoninsku neurotransmisiju i narušene neuroendokrine 7 precese. Kada su u pitanju ženke, rezultati ove studije su pokazali da je LPS poremetio glukokortikoidnu signalizaciju samo u hipokampusu, gde je doveo do smanjene transkripcije gena uključenih u neuroinflamaciju, neuroendokrinu funkciju, serotononsku neurotransmisiju, neuroplastičnost i oksidativnu fosforilaciju.

of the ways in which inflammation can influence the onset of this disease is by affecting the activity od hypothalamic-pituitary-adrenal (HPA) axis, and the levels of glucocorticoids, the end-products of the activity of this axis. Glucocorticoids bind to the glucocorticoid receptor (GR), a ligand-dependent transcription factor that, upon glucocorticoid binding, translocates from the cytoplasm to the nucleus, where it regulates the expression of a large number of genes. GR activity is also regulated by a complex pattern of phosphorylations that affect the transcriptional activity of the receptor. In addition to modulating the expression of nuclear genes, GR and its phosphoforms also affect mitochondrial processes, and may be involved in the process of apoptosis. Sex also plays a significant role in the onset of the disease - in women, depression occurs twice as often as in men. Considering these data, in this study we investigated the effect of the seven-day treatment with an inflammatory agent, lipopolysaccharide (LPS), on the levels and phosphorylation status of GR in the cytosol, nucleus and mitochondria of the prefrontal cortex (PFC) and hippocampus of male and female Wistar rats with depressive-like behavior. We also measured the levels of GR co-chaperones and kinases involved in its phosphorylation in cytosol and nucleus, together with the levels of several caspases and members of the BCL-2 protein family involved in the regulation of apoptosis in the cytosol and mitochondria. In order to determine the effects of changes in phosphorylation on gene expression, the mRNA levels of several nuclear and mitochondrial genes regulated by this receptor and involved in the patophysiology of depression were also measured. The results of this study showed that changes observed in glucocorticoid signaling induced by LPS were associated with processes involved in the onset of depression in a tissue- and sex-specific manner. In males, alterations in glucocorticoid signaling were followed by alterations that suggest decreased neuroplasticity and 9 neuroinflammation, increased oxidative phosphorylation in PFC. On the other hand, alterations in glucocorticoid signalling detected in hippocamous were followed by changes that imply disrupted serotonin neurotransmission and neuroendocrine processes. As for females, the results of this study indicate that LPS disrupted glucocorticoid signaling only in the hippocampus, where it reduced transcription of genes involved in neuroinflammation, neuroendocrine function, serotonin neurotransmission, neuroplasticity and oxidative phosphorylation.

Varijabilnost sadržaja odabranih fenolnih jedinjenja u ekstraktima plodova pet šumskih drvenastih vrsta sa različitih staništa u Srbiji

The variability of selected phenolics contents in fruit extracts of five woody forest species from different habitats in Serbia

Šumske drvenaste vrste (potencijalno) jestivih i/ili korisnih plodova, označene kao samoniklo voće, predstavljaju važan deo specijskog diverztiteta u šumskim ekosistemima Srbije. Vrste Rosa canina L. (Rosaceae), Crataegus monogyna Jacq. (Rosaceae), Prunus spinosa L. (Rosaceae), Cornus mas L. (Cornaceae) i Cornus sanguinea L. (Cornaceae), iako relativno česte u flori Srbije, još uvek nisu dovoljno proučene sa fitohemijskog, kao ni sa ekološko-hemijskog aspekta. Kvalitativna i kvantitativna LC/MS-MS analiza sadržaja određenih hemijskih jedinjenja u populacijama sa međusobno udaljenih staništa, kao i u pojedinačnim jedinkama na mikrostaništu, kao osnovni cilj ovog rada, pružila je informacije o sintezi specifičnih sekundarnih metabolita kao odgovoru na kompleks ekoloških faktora na staništu. Hemijska karakterizacija odabranih vrsta urađena je identifikacijom i kvatifikacijom fenolne kiseline (neohlorogena kiselina [5-O- kafeoilhinska kiselina]) i pet flavonoida (kvercituron [kvercetin-3-O-glukuronid], hiperozid [kvercetin-3-O-galaktozid], rutin [kvercetin-3-O-rutinozid], izokvercetin [kvercetin-3-O- glukozid] i kvercitrin [kvercetin-3-O- ramnozid]) u metanolnim ekstraktima svežih plodova uzorkovanih iz tri prirodne populacije svake vrste. Geografska udaljenost istraživanih populacija (Avala, Zlatarsko jezero i Ozren) omogućila je analizu povezanosti sadržaja ispitivanih fenolnih jedinjenja sa različitim sredinskim uslovima. U metanolnim ekstraktima svežih plodova vrsta R.canina, C. mas i C. sanguinea detektovano je prisustvo svih šest analiziranih fenolnih jedinjenja: neohlorogene kiseline, kvercetin-glukuronida, -galaktozida, -rutinozida, -glukozida i -ramnozida, dok kod vrsta C. monogyna i P. spinosa prisustvo kvercetin-glukuronida nije utvrđeno. U poređenju sa literaturnim podacima ispitivanja plodova kultivisanih i divljih vrsta koje se smatraju bogatim izvorima analiziranih fenolnih jedinjenja (prirodnih antioksidanata), predstavljeni rezultati pokazuju da se prirodne populacije pet šumskih vrsta sa teritorije Srbije odlikuju veoma visokim sadržajem ovih jedinjenja. Ispitivane vrste se značajno razlikuju kako po sadržaju analiziranih fenolnih jedinjenja u ukupnom uzorku, tako i po njihovom procentualnom učešću i varijabilnosti sadržaja. Kod svih ispitivanih vrsta je utvrđen manji ili veći stepen interpopulacione varijabilnosti, a hemometrijskom analizom je utvrđeno koja od ispitivanih jedinjenja najviše doprinose razlikama između populacija. Pokazano je da su sva ispitivana fenolna jedinjenja dobri hemijski markeri za utvrđivanje razlika između vrsta, između populacija i jedinki. Ipak, prema njihovom visokom doprinosu varijabilnosti unutar ukupnog uzorka kod svake od ispitivanih vrsta, izdvajaju se jedinjenja kvercetin-glukozid, - galaktozid i -glukuronid. Analiza korelisanosti sadržaja ispitivanih fenolnih jedinjenja sa sredinskim faktorima pokazala je velike razlike između vrsta, jedinjenja i uticaja pojedinih faktora okruženja, ukazujući na specifičnosti svake vrste u pogledu adaptiranosti na uslove staništa. Na osnovu analize stepena linearne zavisnosti između sadržaja ispitivanih hemijskih parametara i najvažnijih faktora sredine u staništima, pokazano je da najveći uticaj ima prosečna insolacija tokom vegetacijske sezone, zatim nadmorska visina, prosečna temperatura u sezoni rasta i pokrovnost vegetacije, dok prosečna količina padavina u sezoni rasta pokazuje najmani stepen korelisanosti sa sadržajem ispitivanih jedinjenja. Hemijska karakterizacija i kvantifikacija pojedinih biološki aktivnih jedinjenja i povezanost njihovog sadržaja sa pojedinim staništima prirodnih populacija predstavlja značajan pomak u dosadašnjim fitohemijskim istraživanjima, i opravdava potrebu da se prirodne populacije smatraju značajnim genetičkim i hemijskim resursom u sklopu očuvanja biodiverziteta šumskih ekosistema.

Forest woody species with edible and/or useful fruits, known as wild fruit species, are important part of the species diversity in Serbian forest ecosystems. Species Rosa canina L. (Rosaceae), Crataegus monogyna Jacq. (Rosaceae), Prunus spinosa L. (Rosaceae), Cornus mas L. (Cornaceae) i Cornus sanguinea L. (Cornaceae), although relatively frequent in Serbian flora, are still not sufficiently investigated from the phytochemical and chemoecological aspect. Qualitative and quantitative LC/MS-MS analysis of the content of certain phenolic compounds in populations from distant habitats as well as in the individual plants on each habitat, being the objective of this study, provided information of the synthesis of specific secondary metabolites in response to the complex of environmental factors. Chemical characterization of selected plant species was performed through identification and quantification of phenolic acid (neochlorogenic acid [5-O-cafeoilquinic acid]) and five flavonoids (quercituron [quercetin-3-O-glucuronide], hyperoside [quercetin-3-O- galactoside], rutin [ quercetin-3-O-rutinoside], isoquercetin [quercetin-3-O-glucoside] and quercitrin [quercetin-3-O-ramnoside]) in methanol extracts of fresh fruits sampled form three natural populations of each species. The geographical distance of the investigated populations (Mt. Avala, Lake Zlatar, Mt. Ozren) enabled analysis of the relationship between the content of selected phenolic compounds and different environmental factors. The presence of all six analyzed phenolic compounds: neochlorogenic acid, quercetin-glucuronide, -galactoside, -rutinozide, -glucoside and -ramnozide were detected in methanol extracts of the fresh fruits of the species R. canina, C. monogyna, P. spinosa, while in species C. mas and C. sanguinea quecetin-glucuronide was not detected. The results presented in this study showed that populations of wild fruit species from the territory of Serbia are characterized by very high content of analyzed phenolic compounds, in comparison to the literature data regarding wild or cultivated species considered to be a rich sources of the same compounds – validated as powerful natural antioxidants. Studied species significantly differed by the content and showed a great variability of the analyzed phenolic compounds in the total sample, as well as by the share of each compound in total amount of analyzed compounds. All species had lower or higher degree of interpopulation variability, and hemometric analyses revealed which of the studied compounds contributed to the differences between populations. It has been shown that all selected phenolic compounds are good chemical makers for evaluation of intra- and inter-species differentiation. However, the highest contribution to the variability within the total sample in each species is attributed to quercetin- glucoside, -galactoside and -glucuronide. Analysis of the correlations between the content of the phenolic compounds and the environmental conditions showed great differences between the species, the compounds and the influence of certain environmental factors, pointing to the species- specific adaptations to the habitat-specific conditions. Based on the analysis of the degree of linear dependence between the content of the studied chemical parameters and the most important ecological conditions/factors, it has been shown that the greatest impact on the compound’s content has average insolation during the vegetation season, then altitude, average temperature during the vegetation season and vegetation land coverage, while the correlation with the average precipitation during the vegetation season is very low. The chemical characterization and quantification of certain biologically active compounds in natural populations and the connections of their content with specific habitats represents a significant shift in the current phytochemical research, and justifies the need for natural populations to be considered as significant genetic and chemical resources in the biodiversity conservation of forest ecosystem.

Povezanost demografskih i socijalno-ekonomskih determinanti sa nejednakostima u zdravlju žena u Vojvodini

The association of demographic and socioeconomic determinants with inequalities in women's health in Vojvodina

Socijalno-ekonomske nejednakosti u zdravlju jesu važan i stalan javnozdravstveni problem u svim evropskim zemljama. Nejednakost u zdravlju u većini društava podrazumeva da žene imaju manji pristup i kontrolu nad resursima za zaštitu svog zdravlja, kao i manje mogućnosti da budu uključene u odlučivanje o sopstvenom zdravlju. Svi navedeni aspekti u značajnoj meri utiču na zdravlje žena. Cilj ovog rada bio je da se proceni vulnerabilnost u zdravlju žena, korišćenje i razlike u korišćenju zdravstvene zaštite žena, kao i da se identifikuju najznačajnije determinante povezane sa nejednakostima u zdravlju žena. Doktorska disertacija predstavlja deo Istraživanja zdravlja stanovništva Srbije iz 2013. godine koje je sprovedeno od strane Ministarstva zdravlja Republike Srbije. Istraživanjem je obuhvaćeno 1.840 žena uzrasta 20 i više godina sa područja Vojvodine. Instrument istraživanja su bili upitnici konstruisani u skladu sa upitnikom Evropskog istraživanja zdravlja, a podaci o telesnoj masi, telesnoj visini i krvnom pritisku su dobijeni merenjem. Rezultati istraživanja su pokazali da je su najstarije žene u strukturi uzorka, (OR=9,64; 95%CI = [5,79-16,04]; p<0,001), žene nižeg nivoa obrazovanja (OR=2,96; 95%CI = [1,66-5,27]; p<0,001) i materijalnog stanja (OR=2,11; 95%CI = [1,40-3,17]; p<0,001) češće procenile svoje zdravlje kao loše. Kao prediktori lošeg zdravlja izdvojili su se i prisustvo depresije, hroničnih bolesti, izloženost stresu, pušenje, arterijska hipertenzija i slaba socijalna podrška. Istraživanje je potvrdilo postojanje značajnih nejednakosti u zdravlju žena u Vojvodini i identifikovalo najugroženiju kategoriju žena čime daje osnov za unapređenje postojećih i kreiranje novih javnozdravstvenih programa namenjenih ovoj vulnerabilnoj kategoriji.

Socio-economic inequalities in health are an important and constant public health problem in all European countries. Inequality in health in most societies means that women have less access to and control over resources to protect their health, as well as fewer opportunities to be involved in deciding on their health. All of these aspects significantly affect women's health. This study aimed to assess the vulnerability in women's health, the use and differences in the use of women's health care, as well as to identify the most important determinants associated with inequalities in women's health. The doctoral dissertation is a part of the Health Survey of the Population of Serbia from 2013, which was conducted by the Ministry of Health of the Republic of Serbia. The research included 1,840 women aged 20 and over from the area of Vojvodina. The research instrument was questionnaires constructed following the European Health Research Questionnaire, and data on body weight, body height and blood pressure were obtained by measurement. The results of the research showed that the oldest women in the sample structure, (OR = 9.64; 95% CI = [5.79-16.04]; p <0.001) had a lower level of education (OR = 2.96; 95%). CI = [1.66-5.27]; p <0.001) and material condition (OR = 2.11; 95% CI = [1.40-3.17]; p <0.001) had greater odds to perceived their health as poor. The presence of depression, chronic diseases, exposure to stress, smoking, arterial hypertension and weak social support also stood out as predictors of poor self-assessment of health. The research confirmed the existence of significant inequalities in women's health in Vojvodina and identified the most vulnerable category of women, thus providing a basis for improving existing and creating new public health programs for this vulnerable category.

Infrastrukturni koridori i njihov uticaj na prostorni razvoj - primer koridora VII u Srbiji

Infrastructural corridors and their influence on spatial development - example of corridor VII in Serbia

Efikasnije korišćenje geostrateške pozicije Srbije na širem području ukrštanja Panevropskih koridora, Dunavskog (vodnog) VII i (drumsko-železničkog) X, treba da bude jedan od osnovnih principa prostornog razvoja, u domenu transporta...

More effective utilisation of Serbia's geostrategic position on the wider area of "crossing" of Pan/European corridors/danube (water) VII and (road-railroad) X-schould be one of the basic principles of spatial development in transport domain...

Socijalni aspekti u prostornom razvoju rudarskih regiona - mogućnost unapređenja na primeru Srbije

Social aspects in the spatial development of mining regions - Possibility of improvement using the example of Serbia

Predmet istraživanja doktorske disertacije predstavljaju analiza i procena uticaja na društveni (socijalni) razvoj do kojih može doći prilikom različitih procesa prostornog razvoja na području rudarskih regiona, kao i mogućnost unapređenja ove osetljive problematike generalno, a posebno u slučaju Srbije. Na osnovu dosadašnjih relevantnih teorijskih i empirijskih izučavanja, istraživanje je imalo za cilj da utvrdi socijalne (društvene) aspekte uticaja do kojih dolazi u procesu prostornog planiranja razvoja rudarskih regiona, kao i najprikladnije mere usmeravanja, kompenzacije i ublažavanja negativnih uticaja indukovanih razvojem rudarstva i komplementarnih aktivnosti, kako bi se planirane promene što bolje uskladile sa aktuelnim izazovima održivog razvoja. U tom kontekstu je bilo neophodno analizirati i sistematizovati teorijske aspekte i kontekste sagledavanja socijalnih uticaja rudarskih aktivnosti, sa posebnim osvrtom na novije tendencije; analizirati i unaprediti postojeće metodologije, kriterijume i varijable za procenu uticaja rudarskih i pratećih aktivnosti; proučiti pravne okvire: međunarodnu obavezujuću i fakultativnu regulativu, propise međunarodnih organizacija, nacionalno zakonodavstvo, fakultativne smernice i principe i sl.; ispitati i proveriti mehanizme procenjivanja i ublažavanja negativnih uticaja prostornog razvoja rudarskih regiona u Srbiji na društveni razvoj. Na ovim osnovama, u disertaciji je ukazano na nedostatke koji postoje u teoriji i praksi razmatranja socijalnih aspekata u praksi prostornog planiranja u Srbiji, pre svega rudarskih regiona, i koristeći naučna saznanja i iskustva zemalja koje imaju dužu tradiciju u analiziranju ovih pitanja i prilagođavajući ih našim uslovima i mogućnostima, predložena su neka optimalna rešenja ovog problema. ii Teorijsko-metodološka polazišta istraživanja uticaja rudarskih radova na društveni razvoj zasnovana su na paradigmi održivog razvoja, naročito socijalnom aspektu održivosti (koji je potrebno izbalansirati sa, često naglašenijim, ekonomskim i ekološkim aspektima) i u skladu sa tim, novim trendovima i konceptima zaštite ljudskih prava, aktivne participacije javnosti, društveno odgovornog poslovanja, transparentnosti, i dr. Na osnovu prikazanog teorijsko-metodološkog koncepta, istraživanje sprovedeno za potrebe doktorske disertacije razvijeno je u nekoliko međusobno uslovljenih i povezanih celina: uvod, šest poglavlja i zaključna razmatranja. Primereno problemu, predmetu, cilju i postavljenim zadacima istraživanja, analizi referentne literature i obavljenim prethodnim istraživanjima, postavljena je sledeća polazna hipoteza: eksploatacija i prerada mineralnih sirovina imaju značajne uticaje na socijalni razvoj u rudarskim regionima, i njihovo rešavanje predstavlja osnovnu pretpostavku za ukupan održivi razvoj regiona. Pod-hipoteze uključuju: 1) preduslov uspešnog planiranja razvoja rudarskih basena predstavlja procena socijalnih uticaja; 2) prostorno planiranje ima ključnu ulogu u implementaciji mera za ublažavanje negativnih efekata rudarstva; 3) razvoj metodologije za utvrđivanje obima i značaja socijalnih uticaja doprinosi održivom razvoju; 4) dosadašnji političko- društveno-ekonomski razvoj u Srbiji izazvao je značajne probleme i nedostatke u ovoj oblasti; i 5) rezultati ovog istraživanja predstavljaće osnov za poboljšanje kvaliteta života stanovništva u rudarskim regionima u Srbiji. Sprovedeno istraživanje je u potpunosti ili delimično potvrdilo postavljene hipoteze. U skladu sa savremenim saznanjima, kao i potrebama i zadacima istraživanja, uticaj rudarskih aktivnosti analiziran je u istorijskom i savremenom kontekstu, naročito sa aspekta: 1) razvoja rudarskih naselja; 2) prinudnog preseljenja i gubitka zemljišta; 3) ugroženosti starosedelačkog stanovništva; 4) migracije radne snage; kao i 5) uticaja na žensko stanovništvo; 6) podrške rudarskih kompanija zdravstvenoj zaštiti i obrazovanju; 7) korišćenja prinudnog i dečijeg rada; i 8) primene sile. iii Na osnovu sprovedenog istraživanja formirana je teorijsko-metodološka osnova za razumevanje društvenih aspekata i uticaja razvoja u prostornom planiranju rudarskih regiona u Srbiji (Kolubarski, Kostolački, Borski i ostali). Od sredine 1960-ih, rudari u Srbiji su imali relativno visoke prosečne zarade (naročito u proizvodnji uglja, nafte i gasa), a sličan trend je prisutan i danas. Istovremeno, interesi lokalne zajednice su najčešće bili podređeni nacionalnim prioritetima, pa se nije poklanjalo previše pažnje ublažavanju negativnih uticaja do kojih je dolazilo naročito zbog eksprporijacije i raseljavanja stanovništva. Utvrđeno je da su se najznačajniji dosadašnji problemi i nedostaci odnosili na: 1) skroman obim poštovanja imovinskih prava ugroženog stanovništva i prava na zdravu životnu sredinu i kvalitet življenja (slabi mehanizmi za zaštitu prava i interesa građana i lokalnih zajednica); 2) netransparentnost procesa planiranja i donošenja odluka, manipulisanje informacijama o kvalitetu životne sredine i zdravlju stanovništva; 3) površne i retke konsultacije sa zainteresovanim i ugroženim stranama (naročito kada je reč o prinudnom preseljenju); 4) neusaglašenost sa međunarodnim standardima i prihvaćenim obavezama (usvojenim konvencijama, direktivama, i sl.); 5) nedostatak državnog pritiska (zakonodavna uređenost) i podrške (npr. poreskih olakšica) kompanijama da primenjuju društveno odgovorno poslovanje; 6) nedostatak odgovarajuće pravne regulative u oblasti uticaja razvojnih aktivnosti na stanovništvo; 7) monofunkcionalne zajednice; i 8) indukovanje deagrarizacije (često i osiromašenja poljoprivrednog stanovništva) i neravnomernog prostornog razvoja (uz bespravnu izgradnju). Sumarno, na osnovu prethodno izloženog, mogući pravci planiranja razvoja u rudarskim regionima u Srbiji moraju se zasnivati na obaveznosti sprovođenja ex-ante i ex-post facto analize/evaluacije i monitoringa uticaja na stanovništvo i društveni razvoj, i primeniti pristup široke participacije zainteresovane i ugrožene javnosti u svim fazama planiranja. U tom procesu odlučujuća je uloga države koja treba da formira određene legislativne i društveno-političke preduslove. Ovi uslovi obuhvataju: izmene i dopune ključnih zakona i podzakonskih akata u ovoj oblasti (ili usvajanje posebnog integralnog akta koji bi regulisao oblast planiranja rudarskih regiona) i uvođenje obaveze iv sprovođenja posebne procene socijalnih uticaja u slučaju mogućih značajnih uticaja planiranog razvoja, kada instrumenti procene uticaja i strateške procene uticaja nisu dovoljni, razvoj nacionalne politike upravljanja mineralnim resursima; podršku usvajanju i primeni novijih inicijativa u rudarstvu (transparentnost, borba protiv korupcije, društveno odgovorno poslovanje i dr.), uključivanje građana u pripremanje i donošenje plansko- razvojnih odluka, podršku diverzifikaciji privrednih aktivnosti u rudarskim zajednicama, ublažavanje negativnih posledica zatvaranja rudnika (programi za razvoj zajednica nakon završetka rudarskih radova, prekvalifikacija radnika i dr.), posebnu zaštitu osetljivih grupa (dece, starih, žena), regulisanje prava starosedelaca, usmeravanje planiranja i korišćenja zemljišta, analizu i upravljanje uticajima na životnu sredinu i stanovništvo, poresku politiku, inostrane investicije i razmene.

The research topic in doctoral dissertation is the analysis and assessment of the social impact that can occur during the various spatial development processes of mining regions, and the possibility for improving this sensitive topic generally, and especially in the example of Serbia. Based on the existing relevant theoretical and empirical research, this research study aims to establish the social impact during the spatial planning of mining regions, as well as to determine the most suitable measures to direct, compensate and mitigate the negative impact induced by mining and complementary activities, in order to synchronize the planned changes with current challenges of sustainable development. In this context, it was necessary to analyze and systemize the theoretical aspects and contexts when evaluating the social impacts of mining activities, with a special emphasis on recent trends; to analyze and improve existing methodologies, criteria and variables for assessing the impact of mining and related activities; to study the legal framework, including internationally binding and voluntary regulations, the regulations of international organizations, national legislation, voluntary guidelines and principles, etc.; and to examine and verify the mechanisms of assessment and mitigation of negative impacts of spatial development of mining regions in Serbia on social development. On this basis, the thesis points out the flaws that exist in the theory and practice of evaluating the social aspects in planning practice in Serbia, primarily mining regions, and using the scientific knowledge and the experience of countries that have a long tradition in analyzing these issues in order to adapt them to our conditions and opportunities and propose an optimal solution to this problem. The theoretical and methodological starting points for researching the impact of mining activities on social development are based on the sustainable development paradigm, particularly on the social aspect of sustainability (that has to be balanced with, often more emphasized economic and environmental aspects), and are in accordance with vi these new trends and concepts of human rights protection, active public participation, corporate social responsibility, transparency, and related concerns. Based on these theoretical and methodological concepts, the research conducted for this doctoral dissertation is developed in several interrelated parts: an introduction, six chapters, and concluding remarks. In order to frame to this issue, subject, purpose and research tasks, analysis of reference literature and previously conducted research, the following initial hypothesis is set: the exploitation and processing of mineral resources have a significant impact on social development in mining regions, and their solution is a basic prerequisite for overall sustainable regional development. Sub-hypotheses include: 1) a precondition for successful planning of any mining basin is a social impact assessment; 2) spatial planning has a key role in the implementation of measures to mitigate the negative effects of mining; 3) development of a methodology for determining the scope and importance of social impacts contributes to sustainable development; 4) the current political and socio-economic development in Serbia has caused significant problems and deficiencies in this area; and 5) the results of this research will form the basis for improving the quality of life in the mining regions in Serbia. The conducted research has confirmed the hypotheses completely or partially. In accordance with current knowledge and research needs and objectives, the impact of mining activities is analyzed in the historical and contemporary context, particularly in terms of: 1) the development of mining settlements; 2) the forced resettlement and loss of land; 3) The vulnerability of indigenous peoples; 4) labor migration; 5) the impact on the female population; 6) support of mining companies to health care and education; 7) the use of forced and child labor; and 8) the use of force. A theoretical and methodological basis for understanding the social aspects and impact of development in spatial planning of mining regions in Serbia (Kolubara, Kostolac, Bor region and others) is formed based on research. From the mid-1960s, miners in Serbia have had relatively high average wages (especially in the production of coal, oil and gas), аnd similar trend continued today. At the same time, the interests of local community have often been subordinated to national priorities, and there has not been much attention to the mitigation of those negative impacts which were especially induced by expropriation and population displacement. vii It was found that the most important current problems and deficiencies are related to: 1) modest respect for the property rights of affected populations and rights to a healthy environment and quality of life (weak mechanisms for protecting the rights and interests of citizens and communities); 2) lack of transparency within the planning and decision- making process, manipulation of information about the quality of the environment and the health of the population; 3) superficial and rare consultation with the interested and affected population (especially in the case of forced relocation); 4) non-compliance with the international standards and accepted obligations (adopted conventions and directives) 5) lack of government pressure (legislative arrangement) and support (e.g. tax incentives) to companies to implement CSR; 6) lack of an appropriate legal framework in the area of the social impact of development activities; 7) mono- functional community; and 8) the induced deagrarization (often also the impoverishment of rural population), and uneven spatial development (with illegal construction). In summary, based on these issues, the possible directions of development planning in the mining regions of Serbia must be based on the mandatory implementation of ex-ante and ex-post facto social impact analysis/evaluation (and monitoring), and the application of the approach of broad participation of the interested and affected public in all stages of the planning process. In this process, the state has a key role as it has to create specific legislative and socio-political conditions. They include - amendments to key legislation and regulations in this area (or the adoption of a special integrated act to regulate the area of planning mining regions) and obligatory implementation of special social impact assessment in the case of potential significant impacts of the planned development, when instruments of impact assessment and strategic impact assessment is not sufficient; the development of national policy management of mineral resources; support for the adoption and implementation of recent initiatives in the mining industry (transparency, anti-corruption, corporate social responsibility, etc.), the involvement of citizens in decision-making, support for the diversification of economic activities in mining communities, mitigation of the negative effects of mine closure (programs for community development after the end of mining operations, retraining workers etc.), special protection of vulnerable groups (like children, the elderly, women), the directing of planning and land use, the analysis and management of environmental and social viii impacts, tax policy, foreign investment and exchange, and regulation of the rights of the indigenous.

Uticaj promenljivog magnetnog polja (50 Hz, 0,5 mT) na lokomotornu aktivnost i komponente adaptivne vrednosti Drosophila subobscura (Collin, 1936)

Influence of alternating magnetic field (50 Hz, 0,5 mT) on locomotor activity and fitness components of Drosophila subobscura (Collin, 1936)

Pored prirodnog magnetnog polja Zemlje, kome je izložen celokupni živi svet, tehnološkim napretkom i svakodnevnom upotrebom različitih aparata u domaćinstvima i radnim prostorijama povećava se učestalost „veštačkih“ magnetnih polja različitih frekvencija. Promenljiva magnetna polja, koja obuhvataju raspon frekvencija od 0 do 300 Hz se svrstavaju u grupu ekstremno niskofrekventnih magnetnih polja i sve su više prisutna u životnoj sredini. Imajući u vidu njihov uticaj na žive organizme, ova magnetna polja se smatraju važnim ekološkim faktorom. Zbog toga se poslednjih godina ulažu veliki napori u izučavanje njihove interakcije sa biološkim sistemima u okviru discipline magnetobiologija. U brojnim studijama je pokazana osetljivost bioloških sistema na promenljiva magnetna polja na različitim nivoima organizacije, od molekularnog do odgovora na nivou ponašanja jedinki. Lokomotorna aktivnost i komponente adaptivne vrednosti (dužina razvića, dinamika izleganja, preživljavanje i odnos polova) su podložne uticaju spoljašnje sredine, te je od posebnog značaja ispitivanje uticaja promenljivih magnetih polja na pomenute adaptivne karakteristike bioloških sistema. Jedinke Drosophila predstavljaju pogodan model organizam za analizu lokomotorne aktivnosti i komponenti adaptivne vrednosti, čiji se odgovor u nekoj meri može ekstrapolirati i na humanu populaciju. Predmet ove doktorske disertacije je bio da se pokaže postoji li i kakav je uticaj izlaganja različitih stadijuma razvića isofemale (IF) linija Drosophila subobscura promenljivom magnetnom polju (50 Hz, 0,5 mT) u trajanju od 48 sati. Upotreba genetički različitih IF linija D. subobscura omogućila je da se uticaj magnetnog polja ne pripisuje individualnom odgovoru jedinki, već odgovoru pojedinačne linije. Nakon izlaganja različitih stadijuma razvića D. subobscura (jaje-prvi stupanj larve i adulti starosti jedan dan) praćene su lokomotorna aktivnost (pređeni put i pokretljivost) adulata tri dana starosti u open field testu i komponente adaptivne vrednosti (dužina razvića, dinamika izleganja, preživljavanje i odnos polova). Pokazano je da nezavisno od stadijuma razvića koji je izlagan promenljivom magnetnom polju, lokomotorna aktivnost adulata starosti tri dana je značajno smanjena. Smanjena lokomotorna aktivnost adulata, koji su neposredno pre praćenja bili izloženi promenljivom magnetnom polju tokom 48 sati, je bila zabeležena tokom celokupnog vremena praćenja od 30 min. Sa druge strane, kod adulata, koji su izlagani magnetnom polju u stadijumu jaje-prvi stupanj larve, ova promena je utvrđena samo u prvih 10 minuta praćenja. Promenljivo magnetno polje (50 Hz, 0,5 mT) skraćuje vreme potrebno za razviće, povećava preživljavanje i ne utiče na odnos polova D. subobscura. Takođe, između odabranih IF linija, koje su bile različite genetičke strukture, uočena je razlika u odgovoru na primenjeno magnetno polje. Dobijeni rezultati ukazuju na izvestan stepen osetljivosti različitih stadijuma razvića odabranih IF linija D. subobscura na delovanje promenljivog magnetnog polja, kao ekološkog, ali i stresogenog faktora. Uočeni uticaji na lokomotornu aktivnost i komponente adaptivne vrednosti se mogu pripisati uticaju primenjenog magnetnog polja na hormonski i nervni sistem, obzirom da isti imaju važnu ulogu u kontroli ispitivanih parametara.

While all living beings are constantly exposed to the natural magnetic field, they are also exposed to various “artificial” magnetic fields of different frequencies coming from household and office devices. Extremely low-frequency magnetic fields are those ranging from 0 to 300 Hz and they are becoming more present in our environment. These magnetic fields are considered to be an important ecological factor due to their impact on living organisms. In recent years, tremendous efforts are invested in understanding their influence on biological systems within magnetobiology discipline. Number of studies showed biological systems' sensitivity on alternating magnetic fields at different levels, from molecular to behavioural. Locomotor activity and fitness components (developmental time, dynamic of hatching, viability and sex ratio) are subjected to environmental influences. Therefore, it is important to examine the influence of alternating magnetic fields on those adaptive characteristics of biological systems. Drosophila is suitable model organism for analysis of locomotor activity and fitness components, since results can be extrapolated to some degree to human population. Besides investigating the existence of alternating magnetic fields’ impact, the subject of this doctoral thesis is also to reveal consequences of exposing various developmental stages of isofemale (IF) lines of Drosophila subobscura to an alternating magnetic field (50 Hz, 0.5 mT) in duration of 48 hours. Genetically different D. subobscura IF lines were used in order to acquire response of particular line and exclude individual response to the magnetic field. After exposing different developmental stages of D. subobscura (egg-first instar larvae and one day old adult), locomotor activity (distance travelled and mobility) of three-day old adults was observed in an open field test, as well as fitness components (developmental time, hatching dynamic, viability and sex ratio). Locomotor activity of three-day old adults was significantly reduced, regardless of developmental stages and exposure to alternating magnetic field. Decrease in a locomotor activity of adults, exposed to alternating magnetic field in a time frame of 48 hours, was recorded during a 30 minute observation. However, adults exposed to an alternating magnetic field during egg-first instar larvae stadium showed decrease in locomotor activity only during the first 10 minutes. Effects of the alternating magnetic field (50 Hz, 0.5 mT) showed decreased developmental time, viability increase rate and no influence on sex ratio. In addition, different response was recorded in relation to applied magnetic field exposure among selected IF lines with different genetic structure. The obtained results indicate various sensibility among different developmental stages of selected IF lines of D. subobscura after exposure to alternating magnetic field as ecological and stress factor. These effects on locomotor activity and fitness components can be attributed to the influence of alternating magnetic field on hormonal and nervous systems, which have significant role in controlling investigated parameters.

Regulacija genske ekspresije i diverzitet CarO i Omp33-36 porina roda Acinetobacter spp.

Regulation of gene expression and diversity of CarO i Omp33-36 porins in Acinetobacter spp.

Vrste roda Acinetobacter, pre svih Acinetobacter baumannii, su u poslednjih nekoliko decenija od komensalnih stanovnika zdravstvenih ustanova evoluirale u jednu od najozbiljnijih pretnji savremenog zdravstvenog sistema. Globalno rasprostranjenje i konstantan porast izolata Acinetobacter spp. rezistentnih na karbapeneme, antibiotike poslednjeg izbora u leĉenju infekcija izazvanih Gram-negativnim bakterijama, pozicionira ovu grupu bakterija na sam vrh liste patogena za koje je neophodan urgentan pronalazak novih efikasnih antimikrobnih terapeutika. Kontinuirani nadzor nad Acinetobacter spp. rezistenim na karbapeneme, koji podrazumeva praćenje klonalnog širenja i utvrĊivanje molekularnih mehanizama odgovornih za rezistenciju na ovu grupu antibiotika, je prvi korak u uspešnom ograniĉavanju diseminacije navedenih patogenih bakterija. Saznanja o prirodi signala iz spoljašnje sredine, koji mogu uticati na nivo rezistencije na antibiotike i virulencije, ukazuju na uslove pogodne za opstanak A. baumannii i idejno usmeravaju ka pronalasku novih terapeutika. Pored toga, formulacija efikasne vakcine, kao izuzetno znaĉajnog antiinfektivnog agensa, predstavlja jedan od imperativa u eliminaciji infekcija izazvanih višestruko rezistentnim sojevima A. baumannii. U skladu sa prethodno navedenim, ova teza je imala za cilj da molekularno okarakteriše izolate A. baumannii rezistentne na karbapeneme uzorkovane u periodu od 2012. do 2014. godine na Instituta za zdravstvenu zaštitu majke i deteta Srbije „Dr Vukan Ĉupić” (Beograd, Srbija) (n=28). Analizirani izolati A. baumannii su pripadali trima klonalnim grupama karakteristiĉnim za Evropu (Evropski klonovi I-III) sa izuzetkom jednog izolata (8778), koji nije pripadao nijednoj od ove tri grupe. Evropski klon II, najuspešniji bolniĉki Evropski klon, je takoĊe bio najzastupljeniji i meĊu izolatima iz Srbije (67,86%). PFGE metodom izolati A. baumannii rezistenti na karbapeneme su grupisani u dva klastera (I i II), koja su obuhvatala ĉetiri pulsotipa (A-D). Sliĉnost izolata se kretala od 85% do skoro 100%. Budući da je metodom zasnovanom na sekvencama tri gena i PFGE ustanovljena raznovrsnost izolata A. baumannii, može se zakljuĉiti da nije došlo do klonalnog širenja datih izolata unutar bolniĉke ustanove u kojoj su uzorkovani. PCR metodom je detektovano prisustvo gena za uroĊene -laktamaze (AmpC cefalosporinazu i OXA-51 oksacilinazu) kod svih izolata A. baumannii rezistentnih na karbapeneme. TakoĊe, odreĊeni testirani izolati su posedovali gene za steĉene karbapenemaze klase D OXA-23 (57,14%), OXA-24 (82,14%) i OXA-58 (39,29%), kao i ISAba1 sekvencu pozicioniranu uzvodno od blaAmpC (46,43%), blaOXA-51 (3,57%) i blaOXA-23 (35,71%) gena. Kod dva izolata rezistenciji na karbapeneme je doprinosio i porin CarO usled insercione inaktivacije gena koji ga kodira. Steĉene karbapenemaze klase A (KPC), B (IMP, VIM i NDM-1) i D (OXA- 143 i OXA-235), i porin Omp33-36 nisu bili ukljuĉeni u rezistenciju na karbapeneme kod izolata A. baumannii poreklom iz Srbije. Drugi cilj ove teze se odnosio na ispitivanje uticaja razliĉitih signala (faze rasta, subinhibitorne koncentracije karbapenema, hipoksije, kontakta sa keratinocitama i imunskim ćelijama) na transkripciju gena za porine CarO i Omp33-36 kliniĉkih sojeva A. baumannii. Dobijeni rezultati ukazuju da ekspresija carO i omp33-36 gena zavisi od faze rasta bakterija, ali i da je ta zavisnost specifiĉna za pojedinaĉne sojeve A. baumannii. Generalno, subinhibitorne koncentracije karbapenema dovode do smanjenja transkripcije carO i omp33-36 gena kod kliniĉkih sojeva A. baumannii, i to u izraženijoj meri kod soja osetljivog na karbapeneme u odnosu na sojeve koji su rezistentni na ovu grupu antibiotika. TakoĊe, uoĉeno je da subinhibitorna koncentracija meropenema, za razliku od imipenema, u stacionarnoj fazi rasta stimuliše transkripciju carO gena. Ovo zapažanje je u skladu sa ĉinjenicom da je u okviru porina CarO pronaĊeno mesto za vezivanje imipenema, ali ne i meropenema. Uslovi snižene koncentracije kiseonika (hipoksija) ne utiĉu na transkripciju carO gena, ali dovode do smanjenja transkripcije omp33-36 gena. Kontakt A. baumannii sa keratinocitama ĉoveka i imunskim ćelijama pacova znaĉajno stimuliše transkripciju carO i omp33-36 gena. Budući da citotoksiĉni efekat pojedinaĉnih sojeva A. baumannii na keratinocite i imunske ćelije ne koreliše sa transkripcijom carO i omp33-36 gena, pretpostavljeno je da sojevi ukljuĉeni u ovu analizu poseduju faktore virulencije koji imaju razliĉit citotoksiĉni efekat, kao i da postoji mogućnost regulacije ekspresije carO i omp33-36 gena na posttranskripcionom nivou. Sumarno, transkripcija carO i omp33-36 gena regulisana signalima iz spoljašnje sredine može uticati na znaĉaj ovih porina u rezistenciji na antibiotike (subinhibitorna koncentracija karbapenema i hipoksija) ili u virulenciji (kontakt sa ćelijama domaćina) A. baumannii. Analizom nukleotidnih sekvenci carO gena izolata A. baumannii ukljuĉenih u ovu studiju ustanovljeno je prisustvo 5 razliĉitih tipova alela carO gena (prvi tip alela je posedovalo 12 izolata, drugi 14, dok je treći, ĉetvrti i peti tip alela posedovao po jedan izolat). Za razliku od prva tri, ĉetvrti i peti tip alela carO gena su bili inaktivirani ugradnjom razliĉitih insercionih sekvenci. Pored toga, kod analiziranih izolati A. baumannii je ustanovljeno prisustvo dva tipa alela omp33-36 gena (prvi tip omp33-36 alela je posedovalo 16 izolata, a drugi 13 izolata). ML filogenetska analiza je predstavnike roda Acinetobacter (poreklom iz NCBI baze podataka i kolekcije A. baumannii rezistentnih na karbapeneme iz Srbije) prema aminokiselinskoj sekvenci CarO porina podelila u tri osnovne grupe (I-III), koje su obuhvatale šest varijanti (I grupa ĉetiri, a II i III po jednu varijantu). Izolati A. baumannii ukljuĉeni u ovu analizu su bili podeljeni na varijantu I i varijantu III grupe I. Predstavnici roda Acinetobacter su prema aminokiselinskoj sekvenci Omp33-36 porina bili podeljeni u tri grupe (I-III), dok su izolati A. baumannii grupisani u ĉetiri varijante (1-4; varijante 1 i 2 pripadaju grupi III, varijanta 3 grupi II, a varijanta 4 grupi I). Izolati A. baumannii poreklom iz Srbije su bili klasifikovani u varijantu 1 i varijantu 2 grupe III. PRED-TMBB predikcijom transmembranske topologije CarO porina je ustanovljeno da ovaj porin ĉine 10 transmembranskih regiona sastavljenih od -lanaca (-10) i 5 petlji usmerenih ka vanćelijskoj sredini (L1-L5) kod svih opisanih varijanata, dok se organizacija Omp33-36 razlikovala meĊu varijantama od 11 (1-) do 14 transmembranskih regiona sastavljenih od -lanaca (-) i od pet (L1-L5) do sedam petlji usmerenih ka vanćelijskoj sredini (L1-L7). Analiza varijabilnosti pojedinaĉnih pozicija aminokiselina CarO i Omp33-36 porina je ukazala na izuzetnu polimorfnost datih porina (64% i 86%, redom). Broj varijabilnih i hipervarijabilnih regiona je iznosio po 2, a konzervisanih 4 kod sve tri CarO grupe. Razliĉite grupe Omp33-36 su posedovale od 4 do 6 varijabilnih regiona, kao i 4 ili 5 konzervisanih regiona. N-terminalno pozicioniran konzervisani motiv za sve tri CarO grupe je bio AEVGTTGYG, a za sve tri Omp33-36 grupe PLAEAAFL. Navedene osobine porina CarO i Omp33-36, kao i ĉinjenica da njihovi konzervisani motivi imaju unutarćelijsku ili transmembransku lokalizaciju, dovode do zakljuĉka da se ovi proteini spoljašnje membrane ne mogu smatrati adekvatnim kandidatima za profilaktiĉku i terapeutsku imunizaciju. Jedini potencijalni antigen, koji bi mogao biti iskorišćen za proizvodnju vakcine, je PLAEAAFL motiv Omp33-36 grupe II, budući da je samo u ovoj grupi bio lokalizovan u petlji okrenutoj ka spoljašnjoj sredini (L2). PROVEAN analizom je utvrĊeno da većina aminokiselinskih razlika meĊu CarO, kao i Omp33-36 porinima, ne bi trebalo da ispoljava efekat na biološku funkciju datih proteina.

The species of the genus Acinetobacter, primarily Acinetobacter baumannii, have evolved from the commensal residents of health care institutions into the most serious threats of the modern health care system during the last few decades. Global distribution and constant increase of Acinetobacter spp. resistant to carbapenems, antibiotics of the last choice in the treatment of Gram-negative bacterial infections, have positioned this group of bacteria at the top of the list of pathogens that require urgent discovery of novel effective antimicrobial therapeutics. Continuous surveillance of Acinetobacter spp. resistant to carbapenems, which involves clonal spread monitoring and determining the molecular mechanisms responsible for resistance to this group of antibiotics, is the first step in a successful dissemination limitation of these pathogenic bacteria. Knowing the nature of the environmental signals that can affect the level of antibiotic resistance and virulence indicates conditions suitable for the survival of A. baumannii and can direct the invention of new therapeutics. In addition, the formulation of an effective vaccine, as an important anti-infective agent, is one of the imperatives in the elimination of infections caused by a multidrug-resistant A. baumannii strains. In accordance with the aforementioned, the aim of this thesis was molecular characterization of carbapenem-resistant A. baumannii isolates sampled in the period from 2012 to 2014 at the Institute for Health Care of Mother and Child of Serbia "Dr Vukan Cupic" (Belgrade, Serbia). The analyzed A. baumannii isolates belonged to three clonal groups characteristic for Europe (European clones I-III) with the exception of one isolate (8778), which could not be classified to any of these three groups. European clone II, the most successful nosocomial European clone, was also the most frequent among isolates from Serbia (67.86%). Using PFGE method carbapenem-resistant A. baumannii isolates have been classified into two clusters (I and II), which included four pulsotypes (A-D). The similarity of the isolates ranged from 85% to almost 100%. Since the trilocus sequence-based typing and PFGE revealed high diversity of the A. baumannii isolates, it can be concluded that there was no clonal spreading of the analyzed isolates within the hospital institution in which they were sampled. The presence of the genes encoding for intrinsic-lactamases (AmpC cephalosporinase and OXA-51 oxacillinase) was detected in all carbapenem-resistant A. baumanni isolates by the PCR method. Also, some of tested isolates possessed the genes encoding acquired carbapenemases of the class D OXA-23 (57,14%), OXA-24 (82,14%) and OXA-58 (39,29%), as well as ISAba1 sequence positioned upstream of blaAmpC (46,43%), blaOXA-51 (3,57%) and blaOXA-23 (35,71%) genes. In two isolates, CarO porin also contributed to the carbapenem resistance due to insertional inactivation of the gene encoding it. The acquired carbapenemases of class A (KPC), B (IMP, VIM and NDM-1) and D (OXA-143 and OXA-235) and Omp33-36 porin were not involved in carbapenem resistance in Serbian A. baumannii isolates. The second goal of this thesis was to examine the influence of various signals (growth phase, subinhibitory carbapenem concentration, hypoxia, contact with keratinocytes and immune cells) on the transcription of genes encoding for porins CarO and Omp33-36 in clinical A. baumannii strains. The results obtained indicate that the carO and omp33-36 expression depends on the bacterial growth phase, but also that this dependence is specific for each A. baumannii strain. In general, subinhibitory carbapenem concentrations lead to the decrease of the carO and omp33-36 transcription in clinical A. baumannii strains, but in a greater extent in carbapenem- susceptible strain compared to isolates that are resistant to this group of antibiotics. It has also been observed that subinhibitory meropenem concentration, unlike imipenem, at the stationary growth phase stimulates the carO transcription. This observation is in line with the fact that within the CarO porin was found a impenem binding site, but not site specific for meropenem. Conditions of reduced oxygen concentration (hypoxia) have no influence on the carO transription, but lead to a decrease of the omp33-36 transcription. Contact of A. baumannii with human keratinocytes and rat immune cells significantly stimulates the carO and omp33-36 transcription. Since the cytotoxic effect of each A. baumannii strain on keratinocytes and immune cells was not in correlation with the carO and omp33-36 transcription, it is assumed that the strains analyzed in this assay could possess various virulence factors that exibit different cytotoxic effects, and there is also possibility that the carO and omp33-36 expression is post- transcriptionally regulated. In summary, the transcription of the carO and omp33-36 genes regulated by external signals can stimulate the role of these porins in antibiotic resistance (subinhibitory carbapenem concentration and hypoxia) or in virulence (contact with host cells) in A. baumannii. The carO gene nucleotide sequences analysis of A. baumannii isolates included in this study has revealed the presence of 5 different carO gene allel types (12 isolates possessed the first allele type, 14 the second, while the third, fourth and fifth allele type possessed one isolate). Unlike the first three, the fourth and fifth carO gene allel types were inactivated by different insertional sequences. Further, in analyzed A. baumannii isolates has been established the presence of two omp33-36 gene allele types (the first omp33-36 allele type possessed 16 isolates and the second 13 isolates). ML phylogenetic analysis divided the genus Acinetobacter representatives (originating from the NCBI database and A. baumannii from Serbia), according to the CarO porin amino acid sequences, into three basic groups (I-III), which included six variants (I group included four, and in II and III groups was included one variant). A. baumannii isolates involved in this study were divided into variant I and variant III of group I. Representatives of the genus Acinetobacter were classified into three groups (I-III) according to the Omp33-36 amino acid sequences, while A. baumannii isolates were grouped in four variants (1-4; variants 1 and 2 belong to group III, variant 3 to group II and variant 4 to group I). A. baumannii isolates originating from Serbia were classified in variant 1 and variant 2 of group III. The PRED-TMBB prediction of the CarO porin transmembrane topology has revealed that this porin contains 10 transmembrane regions composed of the β-chains (β1-β10) and 5 extracellular loops (L1-L5) in all described variants, while Omp33-36 distinguished between variants from 11 (β1- β11) to 14 transmembrane regions composed of the β-chains (β1- β14) and from five (L1- L5) to seven extracellular loops (L1-L7). The individual amino acid positions variability analysis of the CarO and Omp33-36 indicated that these porins were significantly polimorphic (64% and 86%, respectively). The number of variable and hypervariable regions was 2, and conserved 4 in all three CarO groups. Different groups of Omp33-36 possessed from 4 to 6 variable regions, as well as 4 or 5 conserved regions. The N-terminally positioned conserved motif in all three CarO groups was AEVGTTGYG, and in all three Omp33-36 groups PLAEAAFL. Aforementioned characteristics of CarO and Omp33-36, as well as the fact that their conserved motifs have intracellular or transmembrane localization, lead to the conclusion that these outer membrane proteins could not be considered as adequate candidates for prophylactic and therapeutic immunization. The only potential antigen that could be used for the vaccine production is the PLAEAAFL motif of Omp33-36 group II, since only in this group is localized in a extracellular loop (L2). The PROVEAN analysis showed that most of the amino acid differences between CarO, as well as Omp33-36 porins, should not affect the biological function of these proteins.

Geografski faktori kao determinante intenziteta erozije na primeru sliva Nišave

Geographical factors as erosion intensity determinants of the example of the Nišava river basin

Erozija zemljišta zauzima sve značajnije mesto u sistemu savremenih geografskih, geomorfoloških i interdisciplinarnih istraživanja vezanih za probleme životne sredine. Kao globalni fenomen erozija zemljišta postaje važan faktor kauzalnosti izmeñu prirodne sredine s jedne strane i demografskih, ekonomskih i ekoloških aspekata razvoja odreñenog prostora s druge strane. Glavni karakter ovog procesa je isti u celom svetu, ali je intenzitet procesa različit i zavisi od karakteristika navedenih faktora koji na datom prostoru deluju. Shodno tome, nameće se potreba proučavanja interaktivnog i multikolinearnog delovanja prirodne sredine i ljudske aktivnosti na sam proces. Geografska proučavanja ove problematike predstavljaju polaznu osnovu konkretizacije kauzalnih odnosa sredine u kojoj procesi erozije u većoj ili manjoj meri deluju. Na taj način geografski pristup definiše determinaciju uzroka stanja, ali i potencijalnih posledica koje proces erozije zemljišta, izazvan prirodnim i antropogenim faktorima, implicira na stanje i kvalitet životne sredine. S obzirom na složenost problematike, u disertaciji je interakcija izmeñu dominantnih fizičko-geografskih i antropogenih faktora, koji su uticali na promenu intenziteta erozivnih procesa tokom vremena, utvrdjena na primeru sliva Nišave U tom smislu osnovni ciljevi istraživanja su: kvantifikacija intenziteta mehaničke i hemijske vodne erozije; prostorno-vremenska distribucija intenziteta erozije; utvrdjivanje trenda promene intenziteta erozivnog procesa; utvrdjivanje odnosa izmedju hemijske i mehaničke vodne erozije; determinisanje dominantnih geografskih faktora koji utiču na intenzitet erozije zemljišta. Kako zadaci istraživanja proizilaze iz definisanog cilja istraživanja, mogu se podeliti u više kategorija: ocena postojeće metodologije istraživanja i koncepcijski pristup proučavanja erozije; optimizacija veličine jediničnih polja u cilju ekonomičnog i egzaktnog utvrñivanja intenziteta erozije; numerička diferencijacija fizičkogeografskih i antropogenih faktora; formiranje baze podataka i njene inplementacije u GIS; statistička analiza raspoloživih podataka i formiranje matematičkih modela koji definišu stanje intenziteta erozivnih procesa. Imajući u vidu činjenicu da se erozijom zemljišta bave stručnjaci različitih profila, svaka u domenu svog istraživanja koristi odgovarajuće modele i metode, postavlja odgovarajuće ciljeve i ukazuje na složenost samog procesa. Iz tog razloga u naučnoj i stručnoj literaturi figurira veliki broj različitih metoda i modela. Njihova primena u prvom redu mora biti bazirana na usklañenosti samog metoda ili modela sa stvarnim stanjem na terenu. U metodološkom kontekstu okosnicu rada čini primena tri grupe metoda: empirijski metod, hidrotehnički i hidrohemijski metad. Primenom empirijskog i hidrotehnički metoda utvrdjen je intenzitet promene erozivnog procesa i promene u pronosu nanosa za višegodišnji period osmatranja; a kombinaciija hidrotehničkog i hidrohemijskog metada omogućila je utvrdjivanje pronosa suspendovanog i hemijski rastvorenog nanosa u periodu neposrednih terenskih opservacija za period 2009-2010. godina. Kako intenzitet erozije zavisi od više faktora, u cilju diferencijacija faktora, kao i utvrdjivanja koliki je njihov samostalni i interaktivan uticaj na promene intenziteta erozije, u disertaciji su primenjene i druge naučne metode: metod geomorfološkog kartiranja, metode daljinske detekcije i statističke metode. Uočavanje suštine proučavane pojave, njenog trenda, kao i značaja diferenciranih faktora koji na nju utiču, obradjeno je primenom korelacione analize, regresione analize, trend analize vremenskih serija i faktorske analize. U tu svrhu korišćen je komercijalni program Statistica 10.0, kao i Mann-Kendall test, koji pripada grupi neparametarskih statističkih testova. Za prostorno sagledavanje stanja erozivnog procesa podaci su implementirani u odgovarajući Geografski informacioni sistem. Izbor programskog paketa Geomedia Intergraf omogućio je kompleksnu komparativnu analiza prostora, što je pružilo mogućnost višestrukog modelovanja u smislu davanja različitih vrsta prospekcija, koje mogu da odslikavaju mehaniku samog procesa erozije, ali i svih pratećih faktora koji imaju veće ili manje dejstvo na isti. Dalji rad podrazumeva uspostavljanje faznog postupka u cilju identifikacije promena koje su nastale na prostoru predmetnog sliva. U prvoj fazi sagledan je opšti trend promene intenziteta erozivnih procesa. U drugoj fazi su utvrdjeni dominantni faktori koji su na date promene uticali. U sledećoj fazi pristupilo se analizi faktora koji pod odredjenim uslovima mogu biti dominantni, odnosno u uslovima kada je njihov uticaj vremenski i prostorno ograničen. Izabrani metodološki i koncepcijski pristup i naglasak istraživanja na posmatranje dinamike procesa erozije zemljišta u okviru prostorno-vremenske dimenzije, rezultirao je sledećim zaključkom. Analiza fizičko-geografskih karakteristika terena pokazala je da je prostor sliva Nišave predisponiran za pojavu intenzivne erozije. Medjutim, uporedna analiza stanja erozivih procesa 1970. i 2010. godine pokazala je da je došlo do smanjenja intenziteta i produkcije nanosa na prostoru čitavog sliva, dok je trend analiza vremenskih serija, takodje, pokazala uzastopno smanjenje pronosa suspendovanog u poredjenju sa prethodnim periodom. Kontinuirano smanjenje produkcije i pronosa suspendovanog nanosa bilo je pod snažnim uticajem antropogenog faktora, a delimično i klimatskih promena. Uticaj klimatskih promena najviše se odrazio na pojavu faznog pomeranja koncentracija i pronosa suspendovanog nanosa. Konstatovane sezonske promene u količini i intenzitetu padavina, odrazile su se na promene u trendu proticaja, koje su ostavile posledice na erozivni proces - došlo je do faznog pomeranja koncentracija suspendovanog nanosa od početka leta ka početku proleća. Rezultati analize odnosa izmedju padavinskih uslova, oticanja, koncentracija i pronosa suspendovanog materijala ukazuju na složenu transportnu dinamiku sedimentnog nanosa od njihovog izvora do rečnog toka. Unutargodišnja raspodela datih varijabli pokazala je postojanje dugoročnog histerezis efekta, koji je prostorno diferenciran kroz pojavu tri različite vrste petlji, što znači da u slivu ne postoji jedinstven obrazac preko koga je moguće utvrditi njihovo medjusobno delovanje. Pronos suspendovanog i hemijski rastvorenog nanosa u najvećoj meri definiše promena u količini oticajne vode. Oba tipa rečnog nanosa posmatrana kroz hidrološku komponentu imaju snažno izraženo sezonsko obeležje. Sliv u celini, zapravo, karakteriše postojanje dve sezone u pronosu nanosa. Sezone su polarizovane na zimskoprolećnu i letnje-jesenju sezonu, koje po svojim karakteristikama predstavljaju ekstremne varijante. Definisanje odnosa izmedju suspendovanog i hemijski rastvorenog nanosa prema količini oticajne vode pokazalo je da u periodu malih i srednjih voda hemijska erozija dominantna, dok je u uslovima povećane vodnosti mehanička vodna erozija ta koja dominira u sumarnom pronosu. Vremenska raspodela količine oticajne vode pokazala je da velike vode vremenski traju znatno kraće, ali se za vreme njihovog trajanja trasportuje najveći deo suspendovanog nanosa, što ovaj tip rečnog nanosa definiše kao ekscesivnu kategoriju.

Soil erosion occupies more and more prominent place in the system of modern geographical, geomorphological and interdisciplinary researches related to environmental problems. As a global phenomenon, the soil erosion is becoming an important factor of causality between the environment on the one hand and the demographic, economic and environmental aspects of development of a particular area on the other side. The main character of this process is the same all over the world, but the intensity of the process varies and depends on the characteristics of the specified factors acting on the given area. Consequently, there is a need to study the interactive and multicollinear influence of the environment and human activities on the process itself. Geographical studies of this problem represent the basis of specifying causal relations of the environment where erosion processes are more or less active. In this way, the geographical approach defines determination of the condition causes, but also the potential consequences which the soil erosion process, caused by natural and anthropogenic factors, implies on the condition and quality of the environment. Considering the complexity of the problem, in the thesis the interaction between the dominant physical-geographic and anthropogenic factors, which have contributed to the transformation of the erosion process intensity over time, is established on the example of the Nišava Basin. In this respect, the main objectives of the research are the following: quantification of the mechanical and chemical water erosion intensity; spatio-temporal distribution of the erosion intensity; trend determination of changes in the erosion process intensity; establishment of relations between the chemical and mechanical water erosion; determination of dominant geographical factors that affect the soil erosion intensity. As research assignments arise from the defined research objective, they can be divided into several categories: evaluation of the existing research methodology and conceptual approach to the erosion study; optimization of the unit field size in order to determine a cost-effective and exact erosion intensity; numerical differentiation of physical-geographic and anthropogenic factors; establishment of a database and its implementation in the GIS; statistical analysis of the data available and formation of mathematical models that define the condition of the erosion process intensity. Having in mind the fact that experts of various profiles deal with soil erosion, each in the domain of his research uses the corresponding models and methods, sets the appropriate objectives and points to the complexity of the process itself. For this reason, in the scientific and expert literature figures a large number of different methods and models. Their use in the first place must be based on compliance of the method or model itself with the actual condition in the field. In the methodological context, the framework is made by application of three method groups: the empirical method, hydro-technical and hydro-chemical method. By applying empirical and hydro-tecnical methods, changes of the erosion process intensity and changes in deposit transport for the multi-year period of observation were determined; and the combination of the hydro-technical and hydro-chemical methods enabled the determination of silt and chemically dissolved deposit transport in the period of direct field observations for the period 2009-2010. As the erosion intensity depends on many factors, and in order to differentiate the factors, as well as to determine what is their independent and interactive effect on changes in the erosion intensity, other scientific methods were also applied in the thesis: geomorphological mapping method, remote sensing methods and statistical methods. Realizing the essence of the studied phenomenon, its trend, and also the importance of differentiated factors that influence on it, was done by application of the correlation analysis, regression analysis, trend analysis of time series and factor analysis. For this purpose, a commercial program Statistica 10.0, and also the Mann-Kendall test, which belongs to the group of non-parametric statistical tests, were used. For the spatial assessment of the erosion process condition, the data were implemented in an appropriate Geographical Information System. The choice of a software package Geomedia Intergraph enabled a complex comparative analysis of space, offering the possibility of multiple modeling in terms of providing various types of screening, which may reflect the mechanics of the erosion process itself, as well as all supporting factors that are more or less of the same effect. Further work involves the establishment of the phase procedure in order to identify changes that occurred in the area of the subjected basin. In the first stage the general trend of changes in the erosion processes intensity was considered. In the second phase, the dominant factors that influenced the mentioned changes were defined. In the next phase, we started with the analysis of the factors which under certain conditions could be dominant, that is, at a time when their influence was limited by time and space. Selected methodological and conceptual approach and research emphasis on observations of dynamics of the soil erosion processes in the scope of a space-time dimension, resulted in the following conclusions. Analysis of the physical-geographical characteristics of the terrain showed that the area of the Nišava Basin was predisposed for the intense erosion occurrence. However, the comparative analysis of the erosion processes condition in 1970 and 2010, showed that there was a decrease in the intensity and deposit production in the area of the entire basin, while the trend analysis of time series also showed a consecutive reduction in the silt deposit transport compared with the previous period. Continuous reduction of the silt deposit production and transport was strongly influenced by the anthropogenic factor, and partly by the climate changes. Impact of the climate changes affected mostly the occurrence of phase shifts of the silt deposit concentrations and transport. The identified seasonal changes in the amount and intensity of precipitation, reflected in changes of the discharge trend, which left the effects on the erosion process - there was a phase shift of silt deposit concentration from the beginning of summer to the beginning of spring. The analysis results of the relations between precipitation conditions, runoffs, concentrations and silt deposit transport show a complex transport dynamics of sediment deposit from their spring to the river course. Distribution within the year of the given variables showed a long-term hysteresis effect, which was spatially differentiated by the appearance of three different kinds of loops, which meant that there was no single form through which it was possible to determine their interaction in the basin. Transport of the silt and chemically dissolved deposit is largely defined by a change in the runoff water quantity. Both types of the river deposit observed through the hydrological component have strongly expressed seasonal characteristic. Basin as a whole, in fact, is characterized by the existence of two seasons in the deposit transport. Seasons are polarized in the winter-spring and summer-autumn season, which by their performance represent extreme scenarios. Definition of the relations between the silt and chemically dissolved deposit by the amount of runoff water showed that the chemical erosion was dominant in the period of low and medium-sized water, while in terms of increased water level the mechanical water erosion was the one that dominated the summary transport. Temporal distribution of the runoff water quantity showed that increased water level periods last much shorter, but within the course of their duration, they transported most of the silt deposit, which this type of the river deposit defined as the excessive category.

Geonasleđe srpskog Podunavlja u funkciji orživog razvoja turizma

Geoheritage Serbian Danube region in terms of sustainable tourism development

Geonasleđe čine sve geološke, geomorfološke, hidrološke, pedološke i posebne arheološke vrednosti koje su nastale u toku formiranja litosfere i njenog morfološkog uobličavanja i međuzavisnosti prirode i ljudskih kultura. Iz tog razloga ih treba štiti kao prirodna dobra. Od svih objekta geonasleđa izdvojenog na teritoriji Srbije, 13,2% se nalazi u srpskom Podunavlju. Osnovni ciljevi istraživanja ovog doktorskog rada su: utvrđivanje objekata geonasleđa srpskog Podunavlja i procenjivanje kako oni utiču na uspostavljanje, razvoj i održanje turizma; utvrđivanje prostorno-vremenskog razvoja turizma u srpskom Podunavlju; diferenciranje uticaja pojedinih faktora u fazi formiranja turističkog kretanja i mogućnost kvantificiranja njihovog dejstva u narednom periodu (prognoze i projekcije). Da bi se realizovali postavljeni ciljevi prilikom ovog istraživanja biće korišćeni različiti metodološki pristupi: analitički i sintetički metod, metod korelacije, komparativni metod, kartografske metode, statističke metode, empirijske, terenske metode u kombinaciji sa foto- metodom, anketom i intervjuom, teledetekcione metode, izrada i primena GIS-a. Analizirajući elemente turističke valorizacije geonasleđa srpskog Podunavlja, zaključujemo da se opšta turistička vrednost kreće oko ocene 2, što znači da većina objekata geonasleđa srpskog Podunavlja ima zadovoljavajući kvalitet i lokalni turistički značaj. Najveću turističku vrednost ima Đerdapska klisura koja ima ocenu 4, znači vrlo dobar kvalitet i nacionalni turistički značaj. Ocenu 3, osnosno, dobar kvalitet i regionalni turistički značaj imaju: bigar kod manastira Tumane, kanjon Boljetinske reke, Carska bara, Mačkov sprud, pećina Gradašnica i Rudna glava. Iz tog razloga u srpskom Podunavlju postoje velike mogućnosti objedinjavanja objekata geonasleđa u jedinstvenu turističku turu - Geonasleđe srpskog Podunavlja koja bi verovatno imala velikog uspeha na turističkom tržištu. Oblici geonasleđa bi se kao komplementarne turističke vrednosti mogli uklopiti u već postojeću turističku ponudu ovog dela Srbije. Prilikom izrade ovog rada napravljena je baza podataka sa prostornim podacima i svim dodatnim informacijama koje ih bliže označavaju. Ona predstavlja otvorenu strukturu koja će biti u mogućnosti da se menja i proširuje. Ukoliko bi bila povezana sa internet aplikacijama na savremenim mobilnim telefonima i sl. i obogaćena audio-vizuelnim sadržajima vezanim za svaki objekat geonsaleđa pojedinačno, može da posluži u promociji i realizaciji turističke rute Geonasleđe srpskog Podunavlja. Konkretna uloga GIS-a ovog prostora treba da bude prezentacija i afirmacija njegovih prirodnih i turističkih vrednosti. Na osnovu analize indikatora održivosti turizma u Đerdapu, a koji su propisani od strane eksperata EU, zaključujemo da su kriterijumi uglavnom zadovoljeni. Jedino odstupanje se javlja u slučaju ekonomskih indikatora i to sezonskog karaktera turističkog prometa. Produžavanjem turističke sezone na prolećne i jesenje mesece, organizovanjem različitih manifestacija, odnosno preduzimanjem različitih mera i aktivnosti u smislu turističke ponude i propagande, ovaj se problem može otkloniti. Da bi se razvoj turizma u objektima geonasleđa uskladio sa njegovim kapacitetom i mogućnostima, neophodno je da svi turisti i ostali učesnici u turizmu čuvaju prirodnu sredinu, kao i da se među njima razvijaju norme ponašanja i svest o potrebama budućih generacija za prirodnim, odnosno turističkim resursima. Planovi za uređenje turističke delatnosti u objektima geonasleđa trebalo bi da budu kompromis između razvoja turizma i zaštite prirode. To bi obuhvatalo: analizu resursa, usklađenost resursa i turističkih aktivnosti, usklađenost turističkih aktivnosti sa aktivnostima zaštite sredine i predviđanje negativnih aktivnosti po životnu sredinu.

Geoheritage is made of all the geological, geomorphological, hydrological, pedological and special arhaeological values that occurred during the formation of the lithosphere and its morphological shaping and interdependence of nature and human cultures. Out of all objects of geoheritage isolated on the territory of Serbia, 13,2% are located in the Serbian Danube region. The main objectives of the dissertation are: determining what are the objects of geological heritage of the Serbian Danube region and assessing how they affect the establishment, development and maintenance of tourism; determining the spatio-temporal development of tourism in the Serbian Danube region; differentiating the impact of certain factors in the formation phase of the tourist movement and the possibility of quantifying their effect in the next period (forecasts and projections). In order to achieve the set targets within this study will be used different methodological approaches: analytical and synthetic methods, the correlation method, comparative method, cartographic methods, statistical methods, empirical, field methods in combination with photo-method, surveys and interviews, teledetection methods, design and implementation of GIS. By analyzing the elements of their tourist valorization we can conclude that the general tourist value is about grade 2, what means that most of the geoheritage objects of the Serbian Danube region have satisfactory quality and local tourist importance. The highest tourist value has Djerdap gorge, which has grade 4, what means very good quality and national tourist importance. Grade 3, i.e. good quality and regional tourist importance have Bigar near the monastery Tumane, canyon of the Boljetin River, Carska bara, Mačkov sprud, cave Gradašnica and Rudna glava. For that reason in the Serbian sub-Danube region there are great possibilities for consolidating objects of geological heritage into a unique tourist tour - Geoheritage of the Serbian sub-Danube region, which would probably have great success in the tourist market. The forms of geological heritage as complementary tourist values could fit into already existing tourist offer in this part of Serbia. During the execution of this work the database was created with spatial data and all additional information that indicate them closer. It is an open structure that will be able to be changed and expanded. If it were connected with internet applications on modern mobile phones and alike, and enhanced with audio- visual contents related to each geoheritage object individually it could serve for promotion and realization of tourist route Geoheritage of the Serbian Danube region. The specific role of GIS of this area should be the presentation and promotion of its natural and tourist values. Based on the analysis of indicators of sustainability of tourism, prescribed by EU experts, we conclude that in Djerdap the criteria are generally met. The only exception occurs in the case of economic indicators and seasonal character of tourism turnover. By extending the tourist season in spring and autumn months, organizing different events, i.e. by taking various measures and activities in terms of tourist offer and propaganda, this problem can be eliminated. In order to bring in accordance the development of tourism in geoheritage objects with its capacity and capabilities, it is necessary that all the tourists and other participants in tourism safeguard the natural environment as well as to mutually develop standards of behavior and awareness about the needs of future generations for natural and tourist resources. The plans for the regulation of tourist activity in the geological heritage objects should be a compromise between tourism development and environmental protection. This would include: the analysis of the resources, compliance of resources and tourist activities, compliance of tourist activities with the protection of the environment and prediction of negative actions for the environment.

Nodalni centri - determinanta održivog razvoja sistema naselja Zlatiborskog okruga

The nodal centres - determinant of sustainable development of system settlement in Zlatibor district

Celokupna struktura rada usmerena je na prostor urbane geografije odnosno mreže funkcionalno najznačajnijih naselja kao nosilaca održivog razvoja Zlatiborskog okruga. U osnovi rada zastupljen je funkcionalno-procesni pristup i nodalni regionalizam baziran na skupu prostornih odnosa i veza između hijerarhijski i demografski heterogenih naselja. Primenom ovih principa stvoren je uslov egzaktnog determinisanja prostorne i funkcijske organizacije održivog razvoja sistema naselja Zlatiborskog okruga. Kao osnovni očekivani rezultat i doprinos istraživanja može se označiti celovito sagledavanje funkcijskog razvoja nodalnih centara i njihovog uticaja na socio-ekonomsku transformaciju ostalih naselja. Ideja samog rada je da se geografski složen prostor prikaže u svetlu društveno-ekonomskog razvoja, a kao osnova daljeg privrednog razvoja ovog dela Republike Srbije. Vremenski okvir rada obuhvatio je vremenski period od 1991. godine do poslednjeg popisa 2011. godine, obzirom da su se u ovom periodu desile značajne promene u ukupnom društveno-ekonomskom poretku zemlje. U manjim segmentima korišćeni su podaci ranijih popisa u cilju kvantitativnog poređenja različitih segmenata društvene sfere. Na osnovu postavljenog predmeta, cilja i zadataka istraživanja postavljene su hipoteze objedinjene u: dominantnoj ulozi nodalnih centara kao geoprostornog faktora na održivi razvoj sistema naselja Zlatiborskog okruga; zavisnosti razvoja funkcionalnih centara od strukturnih i demografskih promena unutar socio-ekonomskog prostora; komplementarnosti naseobinskih specifičnosti i razvojnih potreba funkcionalnih centara sublimiranih u održivom razvoju socio-ekonomske sfere naselja Zlatiborskog okruga; perspektivnom razvoju funcijskih centara i integracije u prostorni sistem nodalnih naselja Srbije; izraženosti diferenciranog planiranja i istraživanja održivog razvoja komleksnih geprostornih celina značajnih za sistem naselja Zlatiborskog okruga. Generalnom postavkom rada kroz pet poglavlja analitičkim pristupom izvršena je analiza prostorne organizacije nodalnih i ostalih naselja valorizovanjem složenih interakcija unutar naseobinskih struktura, a preko vrednosti, razmeštaja i funkcijskih parametara. Na osnovu izloženog problemskog pristupa formulisan je zaključak da je održiv razvoj sistema naselja zasnovan na sledećim osnovama: glavna područja koncentracije stanovništva su urbana okruženja; velika uslovljenost društveno-ekonomskog razvoja sistema naselja zasnovan na gravitaciono- podsticajnim i polarizacionim efektima uticaja nodalnih naselja; iz procesa redistribucije u okviru aktivnog stanovništva proističe naseobinsko- funkcijska koncentracija i razvoj ostalih naselja.

The overall structure of this study is focused on the area of urban geography or the network of the most important settlements as the bearers of the sustainable development in the Zlatibor District. The basic part of the study includes the functional - process approach and nodal regionalism based on a set of spatial relationships and connections between hierarchical and demographic heterogeneous settlements. By applying these principals, the condition for the exact determination of the special and functional organization of the sustainable development, in the system of settlements in the Zlatibor District has been created. A comprehensive overview of the functional development of nodal centers and their impact on the socio-economic transformation of other settlements can represent the basic expected result and contribution of this research. The idea behind the study is for the geographically complex area to be displayed in the light of socio-economic development, and as a basis for further economic development of this part of the Republic of Serbia. The time frame of the study includes the period from 1991 to the last census in 2011, given that significant changes in the overall socio-economic order of the country occurred in this period. In smaller segments, the data from previous censuses has been used in order to conduct quantitative comparison between different segments of the social sphere. Based on the set subject, objective and tasks of the research, the hypotheses that were set unified in: the dominant role of the nodal centers as geospatial factors on the sustainable development of the system of settlements in the Zlatibor District; dependency of the development of functional centers from the structural and demographic changes in the socio-economic environment; complementarity of settlements specifities and development needs of the functional centers , sublimated in the sustainable development of the socio-economic sphere of the settlements in the Zlatibor District; promising development of functional centers and the integration into spatial system of nodal settlements in Serbia; expressions of differentiated planning and research of Sustainable Development of complex geospatial units, significant for the system of settlements in the Zlatibor District. By generally organizing the study within five chapters, using analytic approach, an analysis of the spatial organization of nodal and other settlements by valorization of complex interactions within the settlements structures has been performed and through the values ,deployment and functional parameters. According to the previously stated problem-oriented approach, a conclusion is formulated, that the sustainable development of the system of settlements is based on the following grounds: main areas of concentration of the population are urban environments; high conditionality of the socio-economic development of the system of settlements based on the gravity-motivative and polarization effects of nodal settlements′ influence; the settlement- functional concentration and the development of other settlements stems from the process of redistribution within the active population.

Intestinalni i sistemski imunski efekti oralnog unosa kadmijuma kod pacova

Intestinal and systematic immune effects of oral cadmium intake in rats

Kadmijum (Cd) je teški metal koji se nalazi u svim delovima životne sredine, nema poznatu biološku funkciju i ima štetno dejstvo na žive sisteme. Najčešći put izloženosti Cd je oralni, preko kontaminirane vode i hrane, kada je primarna meta toksičnosti ovog metala gastrointestinalni trakt. Poznato je da Cd oštećuje tkivo creva i remeti funkciju epitelne barijere koja je neophodna za održavanje imunske homeostaze, međutim mehanizmi imunotoksičnosti u ovoj regiji nisu dovoljno ispitani. Dodatno, poznato je da toksični efekti Cd mogu da zavise i od genetske osnove / soja eksperimentalnih životinja, ali sojne razlike u intestinalnoj toksičnosti oralnog unosa Cd do sada nisu ispitane. Ova disertacija je imala za cilj karakterizaciju efekta subhronične oralne primene Cd na imunski sistem creva pacova. Pacovi su bili 30 dana oralno (u vodi za piće) izloženi Cd u obliku kadmijum hlorida (CdCl2) u koncentraciji 5 ppm (5 mg Cd/l) i 50 ppm (50 mg Cd/l) Cd, što odgovara dozama prisutnim u životnoj sredini. U okviru lokalnog imunomodulatornog efekta Cd ispitivani su osnovni parametri imunskog odgovora u duodenumu (kao mestu najveće apsorpcije Cd) i mezenteričnim limfnim čvorovima (MLČ) koji dreniraju intestinum. U duodenumu su ispitani pokazatelji tkivnog oštećenja, oksidativnog stresa i zapaljenskih promena, a u MLČ su ispitane osnovne fenotpiske karakteristike i parametri aktivnosti ćelija ovog limfnog tkiva (celularnost, proliferacija, citokinski odgovor, urođeno-imunska aktivnost ćelija). Pored lokalnog, ispitan je i sistemski odgovor na oralni unos Cd uključujući humoralne i ćelijske parametre zapaljenske reakcije u krvi (promene hematoloških parametara, prisustvo medijatora inflamacije i oksidativnog stresa), kao i oksidativni stres i osnovne karakteristike urođenog i adaptivnog imunskog odgovora u slezini, limfnom organu u kome se uspostavlja imunski odgovor na antigene iz krvi. U cilju ispitivanja uticaja genetske osnove na intestinalnu i sistemsku imunotoksičnost oralne izloženosti Cd, lokalni i sistemski efekti su analizirani kod dva soja pacova, Dark Agouti (DA) i Albino Oxford (AO), koji uspostavljaju kvalitativno i / ili kvantitativno različit imunski odgovor na iste stimuluse. Studija je pokazala da oralni tretman Cd dovodi do dozno zavisne akumulacije metala u crevu, MLČ i slezini, slično kod DA i AO pacova, što pokazuje da genetska osnova ne utiče na nivoe deponovanog metala. I pored sličnih koncentracija Cd u crevu oba soja, izraženiji infiltrat mononuklearnih leukocita u tkivu creva, veći stepen nekroze enterocita [meren povećanjem markera nekroze HMGB1 (engl., High Mobility Group Box 1) molekula] i povećana produkcija proinflamatornih citokina (faktora nekroze tumora/TNF, interferona-gama/IFN-γ, interleukina-17/IL-17) pokazani su u tkivu creva DA pacova u odnosu na pacove AO soja. Promena aktivnosti osnovnih enzima antioksidativne odbrane (superoksid dismutaze/SOD i katalaze/CAT), u crevu DA pacova i SOD kod AO pacova, koja predstavlja pokušaj domaćina da ukloni reaktivne kiseonične vrste (engl., Reactive Oxygen Species/ROS) i ograniči oštećenje tkiva, kao i glutation-s-transferaze/GST (enzima odgovornog za vezivanje elektrofilnih supstanci kao što je Cd za redukovani glutation, GSH) bila je takođe izraženija kod pacova DA soja. Ovakav tip promena je verovatno u osnovi povećanja nivoa lipidnih peroksida (mereno promenama malondialdehida/MDA) kod AO pacova. Oralni tretman Cd dovodi do smanjene zastupljenosti laktobacila u crevu DA pacova što može doprineti razvoju proinflamatornog citokinskog odgovora na Cd, dok relativno očuvanje komensalne flore kod AO pacova (uz značajan porast zastupljenosti L. johnsonii i L. murinus) može biti od značaja za očuvanje integriteta crevne barijere i izostanak lokalnog inflamatornog citokinskog odgovora kod ovog soja pacova. Oralni tretman Cd je uticao na aktivnost MLČ kod oba soja pacova (porast mase i celularnosti MLČ, produkcija ROS). Ipak, Cd je indukovao ekspresiju gena za metalotioneine/MT kao i proinflamatorni imunski odgovor (proliferativna aktivnost ćelija MLČ, oksidativne aktivnosti, Th1/Tip1 i Th17/tip17 odgovor) i inhibirao anti- inflamatorni odgovor (ekspresija gena i produkcija interleukina-10/IL-10) samo u MLČ DA pacova. Veći stepen oštećenja i nekroze epitela creva koji je zapažen kod tretiranih DA (u odnosu na AO pacove) je najverovatniji faktor koji je doveo do stimulacije proinflamatornog odgovora u MLČ kod DA pacova. Promene u MLČ DA pacova ukazuju da Cd remeti tolerogenu imunsku sredinu u crevu indukcijom kako urođenog tako i stečenog imunskog odgovora. Iako je ispitivanjem sistemskog efekta oralno unetog Cd ukazano, generalno, na slab uticaj metala na osnovne hematološke i biohemijske parametare u perifernoj krvi, zapažen je efekat na antioksidativne aktivnosti eritrocita kod oba soja pacova. Povećani nivoi HMGB1 molekula u krvi samo DA pacova sugerišu veći stepen oštećenja organa i inflamatorni karakter imunskog odgovora na Cd kod ovog soja pacova. Iako se ista količina Cd deponuje u MLČ i slezini, odgovor u ova dva imunska organa se razlikuje čime je pokazano da je za praćenje efekata Cd od velike važnosti i mikrosredina ispitivanog tkiva. Za razliku od MLČ, u slezini oralni tretman Cd nije uticao na masu i celularnost ali je doveo do smanjene vijabilnosti i smanjene proliferativne aktivnosti ćelija slezine, dok je slično kao i u MLČ, zabeležena povećana oksidativna aktivnost ćelija slezine (aktivnost mijeloperoksidaze/MPO, produkcija azot- oksida/NO) i povećana nestimulisana produkcija proinflamatornih citokina (interleukina-1 beta/IL-1ß, IFN-γ, IL-17) i to samo kod DA pacova. Ovaj proinflamatorni citokinski odgovor ćelija slezine kod DA pacova može se dovesti u vezu sa povećanim nivoom HMGB1 molekula u slezini. Izraženiji proinflamatorni odgovor na oralni tretman Cd u crevu kao i u MLČ i slezini DA u odnosu na AO pacove (kod kojih su nađene slične koncentracije deponovanog Cd) pokazuju da su DA pacovi podložniji oralnom subhroničnom tretmanu ovim metalom. Rezultati ove studije doprinose razumevanju mehanizama koji leže u osnovi toksičnih efekata Cd na imunski odgovor u crevu, pokazujući po prvi put uticaj ovog metala na homeostazu urođenih i adaptivnih komponenti imunskog odgovora u MLČ. Ona je istovremeno pokazala i značaj tkiva u ispoljavanju imunotoksičnosti Cd. Takođe, ova studija je po prvi put ukazala na uticaj genetske osnove na efekte oralno unešenog Cd, sugerišući na značaj pažljivog odabira soja eksperimentalnih životinja koji će se koristiti za analizu imunotoksičnih efekata ovog metala.

Cadmium (Cd) is a heavy metal which is found in every part of the environment, it does not have any known biological function and has an adverse effect upon the living systems. The most common way of Cd exposure is orally, through contaminated water and food, where the prime target of this metal toxicity is the gastrointestinal tract. It is known that Cd causes damage to intestinal tissue and disrupts the epithelial barrier function which is necessary for maintaining immune homeostasis, however, the immunotoxicity mechanisms in this region have not been examined sufficiently. Additionally, it is known that Cd toxic effects may depend also on genetic background / strain of experimental animals, but the strain-dependent differences in intestinal toxicity of oral Cd intake have not been examined to date. This dissertation was aimed at characterization of the effect of subchronic oral Cd administration on rat’s intestinal immune system. Rats were, for 30 days, orally (in drinking water) exposed to Cd in the form of cadmium chloride (CdCl2) at concentration of 5 ppm (5 mg Cd/l) and 50 ppm and (50 mg Cd/l) of Cd, which corresponds to the doses present in the environment. Within the local immunomodulatory Cd effect, basic parameters of immune response in duodenum (region of greatest Cd absorption) and in mesenteric lymph nodes (MLN) which drain intestine, were investigated. The indicators of tissue damage, oxidative stress and inflammatory changes were tested in duodenum, whereas in the MLN basic phenotype characteristics and parameters of this lymph tissue cells' activities (cellularity, proliferation, cytokine responses, and innate-immune cell activity) were tested. Besides the local, the systemic response to oral Cd intake was tested as well, including humoral and cellular parameters of the inflammatory reaction in blood (changes in hematological parameters, presence of inflammatory mediators and oxidative stress), as well as oxidative stress and basic characteristics of the innate and adaptive immune response in the spleen, a lymph organ in which immune response to blood borne antigens are generated. Aiming to test the contribution of genetic background to intestinal and systemic immunotoxicity of oral Cd exposure, local and systemic effects were analyzed in two rat strains, Dark Agouti (DA) and Albino Oxford (AO), which establish qualitatively and/or quantitative different immune response to the same stimuli. The study has shown that oral Cd treatment leads to dose-dependent accumulation of this metal in intestine, MLN and spleen, similarly in DA and AO rats, which demonstrates that genetic background has no effect on the metal deposition levels. Despite similar Cd concentrations in the intestine of both rat strains, more pronounced mononuclear leukocytes infiltrates in intestinal tissue, higher degree of enterocytes necrosis [measured by increased necrosis marker HMGB1 (High mobility group box 1) molecule] and the increased production of proinflammatory cytokines (tumor necrosis factor/TNF, interferone-gamma/IFN-γ, interleukin-17/IL-17) were shown in intestinal tissue of DA rats compared to rats of AO strain. The change in activity of basic enzymes of anti-oxidative defense (superoxide dismutase/SOD and catalase/CAT), in intestine of DA rats and SOD in AO rats, which depicts host tissue attempt to counterattack reactive oxygen species (ROS) and limit tissue damage, as well as glutathione-s-transferase/GST (the enzyme responsible for electrophilic substances binding, such as Cd, to the reduced form of glutathione, GSH), was also more expressed in rats of DA strain. Such type of changes is probably in the background of the increased level of lipid peroxides (measured by the changes of malondialdehyde/MDA) in AO rats. Oral Cd treatment results in reduced prevalence of lactobacilli in DA rats' intestine which may contribute to the development of proinflammatory cytokine response to Cd, whereas relative preservation of commensal flora in AO rats (along with significant increase in prevalence of L. johnsonii and L. Murinus) might be of significance for preservation of gut barrier integrity and absence of the local inflammatory cytokine response in this strain of rats. Oral Cd treatment affected the MLN activity in both strains of rats (increase of MLN mass and cellularity, ROS production). Nevertheless, Cd induced metalotioneinas/MT gene expression as well as proinflammatory immune response (MLN cells' proliferative activity, oxidative activities, Th1/Type1 and Th17/Type17 response) and inhibited anti-inflammatory response (interleukine-10/IL-10 gene expression and production) only in MLN of DA rats. Higher degree of intestinal epithelium damage and necrosis observed in DA treated rats (compared to AO rats) is the most likely factor which stimulated proinflammatory response in MLN of DA rats. The changes in MLN of DA rats indicate that Cd disrupts the tolerogenic immune environment in the gut by induction of both innate and the acquired immune responses. Although the investigation of the systemic effect of orally administered Cd indicated, in general, slight effect of the metal on the basic hematological and biochemical parameters in the peripheral blood, the effect on anti-oxidative activities of erythrocytes in both strains of rats was noticed. The increased levels of HMGB1 molecule in blood of DA rats only, suggests higher degree of organs damage and inflammatory character of immune response to Cd in this strain of rats. Although the same quantity of Cd is deposited in MLN and spleen, the response in these two immune organs differs, showing that the micro environment of the examined tissue is also of great importance in observing Cd effects. Unlike MLN, the oral Cd administration did not affect spleen mass and cellularity but it resulted in reduced viability and reduced proliferative activity of spleen cells, whereas, similar as in MLN, the increased oxidative activity of spleen cells (activity of myeloperoxidase/MPO, nitrogen-oxide/NO production) was noted and the increase of non-stimulated production of proinflammatory cytokines (interleukine-1 beta/ IL-1ß, IFN-γ, IL-17) was noted, only in DA rats. This proinflammatory cytokine response of spleen cells in DA rats may be associated with increased level of HMBG1 molecule in the spleen. More pronounced proinflammatory response to oral Cd administration in gut as well as in MLN and spleen of DA rats in comparison to AO rats (in which similar concentrations of deposited Cd were found) show that DA rats are more susceptible to oral subchronic administration of this metal. The results of this study contribute to the understanding of the mechanisms which underlie the toxic Cd effects on immune response in intestine, for the first time showing the effect of this metal on homeostasis of innate and adaptive components of immune response in MLN. At the same time, this study has also shown the significance of tissue in expressing Cd toxicity. Also, for the first time, this study has indicated the effect of genetic background on orally administered Cd effects, suggesting the significance of careful selection of experimental animals to be used in the analysis of immunotoxic effects of this metal.

Distribucija, status i ishrana vuka (Canis lupus L., 1758) na teritoriji Bosne i Hercegovine

Distribution, status and diet of the wolf (Canis lupus L., 1758) in the territory of Bosnia and Herzegovina

Nažalost, usljed nepostojanja sistematskih ekoloških istraživanja, gotovo se ništa ne zna o njegovoj ekologiji, prostornoj distribuciji i gustinama populacija. Vuk ima različit status zaštite u Bosni i Hercegovini, i uslovljen je različitim entitetskim zakonima. Kako do sada na prostoru Bosne i Hercegovine nije bilo sveobuhvatnih, sintetičkih istraživanja ekologije, genetike, ili bilo koje vrste idioekoloških istraživanja ove krupne karnivore, to definisani ciljevi ove disertacije treba da daju doprinos poznavanju ekologije vuka i populacionog statusa vuka u BiH kao osnove za dalje održivo upravljanje, zaštitu i izradu nacionalnog akcionog plana. Ciljevi disertacije su: definisanje distribucije vuka na području BiH; definisanje prostora sa najvećim gustinama populacija; analiziranje prirode ishrane vuka u BiH; analiziranje sezonske varijabilnost ishrane vuka; analiziranje obima napada na domaće životinje i njihov prostorni i vremenski aspekt; da na osnovu genetičkih i morfometrijskih analiza odredi populacioni status u odnosu na susjedne dinarske populacije i prijedlože mjere za održivo upravljanje i očuvanje vuka u BiH. Analiza distribucije vuka u Bosni i Hercegovini je bazirana na prikupljenim statističkim podacima o odstrelu, anketama, evidenciji šteta, pregledom lovačke periodike i dnevnih novina za period 2003-2013. godine. Distribucija vuka u BiH je prikazana na UTM (MGS) koordinatnom sistemu sa veličinom kvadrata od 10x10 km. Analiza ishrane vuka na prostoru Bosne i Hercegovine je bazirana na analizi fecesa. Feces je prikupljan tokom perioda 2009- 2013. godine na dva transekta (Tisovac i Manjača) u dužini od po 10 km. Sastav ishrane vuka je izražen preko relativne učestalosti pronalaženja neke kategorije/tipa hrane (%O, broj nalaza neke kategorije hrane / ukupan broj nalaza svih kategorija x 100) i procenta konzumirane biomase (%B, masa određene kategorije hrane / ukupna masa svih kategorija x 100). Podaci o štetama su prikupljani za period od 2003 do 2014 godine. Za analizu šteta prikupljani su samo podaci zasnovani na direktinim opservacijama šteta na domaćim životinjama (vuk ili čopor viđeni na licu mjesta, odstreljena/e jedinka/e na mjestu štete i sl.). Štete su obrađene i prikazane prema vrsti stradale stoke (ovce, koze, goveda, svinje, konji, lovački psi, ostali psi) i godine u kojoj je šteta načinjena.

Regarding Bosnia and Herzegovina territory, the wolf is an autochthonous and widely distributed species. Unfortunately, due to lack of systematic ecological studies, the knowledge of its ecology, spatial distribution, and population density is poor. The level of protection of wolves in Bosnia and Herzegovina varies as a result of different entity laws. Up to now, there have been no extensive and synthetic studies on the ecology, genetics, or any other idio-ecological studies on these large carnivores. Therefore, the defined aims of this dissertation should further account for the knowledge of the ecology of wolves and their population status in B&H as a background for future sustainable management, protection, and a national action plan. The aims of the dissertation are as follows: to define the wolf distribution in B&H territory; to define the area with the highest wolf population density; to analyze the wolf natural diet in B&H; to analyze the seasonal variability of wolf’s diet; to analyze the frequency of attacks on livestock, and their spatial and time framework; to determine the population status in comparison with the neighbouring populations based on the genetic and morphometric analyses and suggest measures of sustainable management and preservation of the wolf in Bosnia and Herzegovina. The analysis of the wolf distribution in Bosnia and Herzegovina is based upon the collected statistical data on wolf cull, questionnaires, damage records, and hunter journals and daily papers for 2003-2013 period. The wolf distribution in B&H is displayed on the UTM (MGS) coordinate system with the 10x10 km plot size. The wolf diet analysis in B&H was run on the faecal matter data. The feacal matter had been collected in 2009-2013 period at two transections (Tisovac and Manjača) each having been 10 kilometres long. The food content was expressed via the relative frequency of detection of the food type/category (%O, number of detections of a food category/the sum of all detections for all categories x 100) and percentage of the consumed biomass (%B, mass of a specific food category/ the total mass of all categories x 100). The damage records had been collected for 2003-2014 period. For the purpose of damage analysis, only data on direct observations from damages on domestic animals were used (a wolf or a pack of wolves seen on site, one or more individuals killed at site, etc.)...

Uticaj modifikatora na polimorfiju dolina u krasu Karpato-balkanida Srbije

The influence of modifiers on the polimorphy of valley in karst of the serbian carpatho-balkanides.

Analizom osnovnih morfoloških karakteristika dolina u krasu Karpato-balkanida Srbije utvrđeno je postojanje njihove morfološke raznolikosti (polimorfije). Polimorfija dolina u krasu se javlja kao posledica uticaja pojedinih modifikatora tokom procesa nastanka dolina. Cilj disertacije je objašnjavanje uzročnosti i zakonitosti uticaja modifikatora na pojavu polimorfije dolina u krasu Karpato- balkanida Srbije i određivanje dominantnih modifikatora polimorfije dolina u krasu. Istraživanje je sprovedeno na 2717 dolina (kvalitativna analiza), odnosno, na odabranom uzorku od 910 dolina (kvantitativna analiza). Komparativnom analizom svih dobijenih rezultata tokom istraživanja zaključeno je da u objašnjenju morfološke raznolikosti dolina u krasu Karpato-balkanida Srbije dominira nekoliko modifikatora. Ni jedan od ovih modifikatora ne deluje samostalno, već je evidentan zajednički uticaj više dominantnih modifikatora. Dominantni modifikatori koji utiču na polimorfiju dolina u krasu Karpato-balkanida Srbije su: kontakt karbonata sa nekarbonatnim stenama, padavine, hidrološka funkcija dolina, nagib dna doline i nagib reljefa u koji je dolina usečena, debljina karbonatne mase, pukotinska poroznost i intenzitet kraškog procesa.

The analysis of basic morphological characteristics of the valleys in karst of the Serbian Carpatho-Balkanides showed the noticeable morphological differences (polymorphism). Polymorphism is a consequence of the influence of modifiers during the process of valley origin. The aim of the dissertation is to explain the causality of this influence within the case study of valleys in karst of the Serbian Carpatho-Balkanides, as well as to determine the dominant modifiers. The qualitative analyses are conducted on 2717 valleys and quantitative analyses on selected samples of 910 valleys. The comparative analysis of all the obtained results showed that several modifiers are dominant. None of these modifiers operates independently, but the combined effect of several dominant modifiers is evident. Dominant modifiers which lead to the polymorphism of valleys in karst of the Serbian Carpatho-Balkanides are: the contact of carbonate and non-carbonate rocks, precipitation, hydrological function of the valleys, inclinations of the valley floor and of the terrain in which the valley is incised, the thickness of carbonate rocks, fissure permeability and the intensity of karst process.

Konvergentne i divergentne dnevne migracije stanovništva Pančeva

Convergent and Divergent Commuting Flows of Pančevo Population

U ovoj disertaciji težište je na proučavanju migracionih tokova stanovništva u dnevnom urbanom sistemu Pančeva. Analiza dnevnih migracija stanovništva na nacionalnom nivou, koja je izvršena nakon diskusije teoretskih saznanja iz ove oblasti, omogućava poređenje razvoja i savremenih tendencija odvijanja dnevnih migracija u Srbiji i šire. Faktori koji utiču na odluke vezane za proces dnevnih migracija u Srbiji i prostornu razdaljinu putovanja ispitani su na primeru dnevnih migranata Pančeva. Za potrebe ovog istraživanja dodatno su obrađeni podaci Popisa stanovništva iz 2002. godine, kako bi se povezale popisnice za lice i domaćinstvo. Na osnovu toga su ispitane karakteristike porodice i domaćinstva dnevnog migranta i uticaj faze životnog ciklusa na dnevnu migraciju. Specifičnost Pančeva koja se ogleda u širem nacionalnom i regionalnom značaju pančevačke industrije, kao i neposrednoj blizini Beograda, bila je važna polazna osnova prilikom proučavanja. Definisano je funkcionalno područje Pančeva i određen demografski profil dnevnog migranta urbanog sistema Pančeva. Dodeljivanjem varijable “dužina puta” dnevnom migrantu izvršeno je testiranje uticaja demografskih i socio-ekonomskih faktora na prosečnu dužinu putovanja dnevnog migranta u jednom smeru, a što je omogućilo potvrdu različitog delovanja demografskih i socio-ekonomskih faktora na prostornu razdaljinu dnevne migracije za muškarce i žene. Pomoću softverskog programa SAS ispitana je statistička značajnost razlika u prostornoj razdaljini dnevne migracije prema polu. Bračni status i prisustvo dece, kao najčešće korišćeni indikatori za ispitivanje hipoteze o odgovornosti u domaćinstvu, pokazali su se značajni i za varijacije u prostornoj razdaljini dnevne migracije prema polu na primeru dnevnih migranata Pančeva. Takođe je analiziran uticaj broja zaposlenih u domaćinstvu i porodične strukture na prostornu razdaljinu dnevne migracije, kao i veza između dnevne migracije i migracije sa promenom mesta prebivališta.

This dissertation deals with convergent and divergent commuting flows of population in daily urban system of City of Pančevo (Serbia). Analysis of commuting on national level, gained after discussion of theoretical cognitions in this field, enables comparison between development and modern tendencies of commuting in Serbia and other countries. Determinants that affect commuting decisions and mean travel distance of commuters in Serbia were examined on example of City of Pančevo commuters. For this group of commuters data from 2002 Census have been additionally processed that enabled linkage of commuters and their household members. Based on this data, family types of commuters and effect of life cycle on commuting have been analyzed. The research started from discussion of national and regional importance of Pančevo as industrial town and its favorable location near Belgrade. Funcional area of Pančevo has been defined together with demographic profile of commuter of daily urban system of Pančevo. By allocating of the variable “mean travel distance” to commuter, we have tested influence of demographic and socioeconomic determinants on the mean travel distance of commuter in one way. That enabled us to confirm different acting of demographic and socioeconomic factors on mean travel distance for men and women. The SAS program has been used to explore statistical significance of differences in everyday spatial distance of commuters by sex. Marital status and presence of children, as often used indicators for examining hypothesis of household responsibility, proved to be important for variations in mean travel distance of commuters on example of daily urban system of Pančevo. Mean travel distance differences between dual and single earner households, effects of family and household structure and relations between commuting and migration have also been analyzed.

Expression and activity of antioxidant enzymes in the liver of male and fimale fructose-fed rats

Експресија и активност ензима антиоксидативне заштите у јетри мужјака и женки пацова након исхране обогаћене фруктозом

Prekomerno konzumiranje fruktoze povezuje se sa metaboličkim sindromom i njegovim posledicama, a oksidativni stres je jedan od pretpostavljenih mehanizama na kojima se zasnivaju štetni efekti fruktoze. Cilj ove studije bio je da se ispita da li ishrana bogata fruktozom indukuje oksidativni stres u jetri i na taj način doprinosi pogoršanju metaboličkih poremećaja na polno specifičan način. U tom cilju, izložili smo mužjake i ženke pacova umereno- i visoko-fruktoznoj ishrani tokom perioda od odvajanja od majke do polne zrelosti i potom izmerili: dnevni unos hrane, tečnosti i energije; fiziološke i biohemijske parametre; ekspresiju i aktivnost antioksidativnih enzima, markera lipidne peroksidacije i oštećenja proteina u jetri. Kod svih pacova hranjenih fruktozom, bez obzira na pol i režim ishrane, zapaženo je smanjenje unosa hrane; povećanje unosa tečnosti i energije, i trigliceridemije; kao i nepromenjena telesna masa, insulinemija i nivo triglicerida u jetri. Ženke na umerenoj i mužjaci na visoko-fruktoznoj ishrani imali su povećan indeks adipoznosti. Nivo masnih kiselina u plazmi bio je povećan samo kod mužjaka na umerenoj dijeti. Aktivnost i nivo antioksidativnih enzima, kao i markera lipidne peroksidacije i proteinskih oštećenja nisu bili promenjeni u jetri pacova oba pola hranjenih fruktozom. Jedini izuzetak bio je mitohondrijski enzim SOD2 kod mužjaka. U zaključku, umereno-fruktozna ishrana dovela je do polno specifičnih metaboličkih poremećaja kod mladih pacova, što je rezultat aktivacije lipolize u masnom tkivu mužjaka i lipogeneze u masnom tkivu ženki. Prekomerni unos fruktoze ishranom nije izazvao oksidativni stres u jetri pacova oba pola. Ipak, potrebno je dalje ispitati moguću medijatornu ulogu mitohondrijske SOD2 u razvoju insulinske rezistencije.

Fructose overconsumption has been related to metabolic syndrome and its sequels. Oxidative stress has been proposed as a mechanism underlying adverse metabolic effects of fructose. The aim of this study was to learn whether fructose-rich diet induces hepatic oxidative stress, thus contributing to aggravation of metabolic disturbances in a gender-dependent manner. Toward that aim, we exposed male and female rats to moderate and high fructose diet over a period from weaning to adulthood, and subsequently evaluated: daily food, liquid and energy intake; physiological and biochemical parameters; expression and/or activity of hepatic antioxidant enzymes, and markers of lipid peroxidation and protein damage. A decrease in food intake; an increase in liquid intake, energy intake and triglyceridemia; and no changes in body mass, insulinemia and the level of hepatic triglycerides were observed in all fructose-fed rats as compared to controls, irrespectively of the gender and the diet regime. Females on moderate and males on high fructose diet displayed increased adiposity. Plasma levels of NEFA were increased only in males on moderate diet. The activity and level of hepatic antioxidant enzymes, and markers of lipid peroxidation and protein damage were not altered in rats of both genders in response to both diets, the only exception being mitochondrial SOD2 function in males. In conclusion, moderate fructose diet led to gender-specific metabolic disturbances in young rats, resulting from activation of adipose tissue lipolysis in males and lipogenesis in females. Fructose overconsumption did not provoke hepatic oxidative stress in the rats of any gender. Nevertheless, a possible mediatory role of mitochondrial SOD2 in development of insulin resistance needs further investigation.

Teorijsko-metodološke osnove definisanja kriterijuma i indikatora prostornog razvoja Srbije

Teorethical and methodological basis for defining criteria and indicators for spatial development of Serbia

Kriterijumi i indikatori se koriste kao standardno sredstvo u gotovo svim segmentima prostorno-planerskog procesa. Kriterijumi, kao odraz društvenih vrednosti, sagledavaju se prvenstveno kroz pravila, standarde i norme u organizaciji, korišćenju, uređenju i zaštiti prostora. Indikatori predstavljaju merljiva obeležja prostornih fenomena, kojima se mogu pratiti i kontrolisati procesi i pojave u prostoru i ocenjivati ostvarivanje planskih ciljeva i utvrđenih kriterijuma. Primenjeni kriterijumi i indikatori u prostornim planovima, njihova objektivnost, ažurnost i pouzdanost, zapravo odražavaju razvoj prostornog planiranja kao društvene prakse i kao discipline utemeljene na naučnim osnovama. Kao društvena praksa, prostorno planiranje podleže društvenim i političkim promenama koje znače promene u sistemu vrednosti i ciljevima, pa tako i u kriterijumima vrednovanja prostora. S druge strane, prostorno planiranje nalazi svoju naučnu zasnovanost u prirodnim i humanističkim naukama uvažavajući metode i rezultate istraživanja složenih i brojnih pojava i procesa u prostoru. U istraživanjima prostornog razvoja, a posebno u praktičnom radu - u izradi prostornih planova, teme o kriterijumima i indikatorima uvek su aktuelne i predmet su stalnog preispitivanja. Stanovište da 'vrednujemo ono što merimo, a merimo onako kako vrednujemo' pokazuje dinamičnost i neraskidivost ovih tema, što je za planiranje i uređenje prostora poseban izazov. Promene u sistemu vrednosti zapravo označavaju promene u modelu planiranja ili čak ii promene odnosa prema prostoru, kroz nove planske paradigme u izboru ciljeva, prioriteta i uloge aktera koji su uključeni u proces planiranja. Potreba za kriterijumima proizlazi iz normativne snage prostornog plana, koji neposredno obavezuje korisnike prostora i nosioce razvoja da poštuju pravila, precizirajući šta se sme, a šta ne sme činiti u prostoru. Norme su neophodne jer ova zakonodavna oblast obuhvata i niz pravnih konsekvenci (eksproprijacija zemljišta, koncesije, režimi korišćenja prostora, uslovi izgradnje, inspekcija, sankcije i dr.), kojima se utiče na obezbeđivanje privatnog i javnog prava, odnosno ostvarivanje privatnih i javnih interesa. Cilj istraživanja je da se utvrde osnovni skupovi usaglašenih kriterijuma i indikatora za prostorne planove, tako da ovi planovi budu primenljivi i dovoljno koordinirajući za planske odluke o izgradnji i korišćenju prostora. Teorijsko uporište koncepta kriterijuma i idikatora za prostorno planiranje istražuje se u okviru uzročno-posledičnih odnosa i procesa, traganjem za osnovnim univerzalnim vrednostima prostornog razvoja. U radu se izdvaja nekoliko aspekata prirodnih zakonitosti, ekonomskih uslovljenosti i društvenih uslovljenosti, iz kojih se mogu sagledati ishodišta za pravila i kriterijume u korišćenju i organizaciji prostora. Ispituje se univerzalnost postojanja nekih pravila, u vremenu i prostoru, kao i različitost pravila u različitom društvenom kontekstu. Jedna od glavnih odrednica istraživanja je prevashodna povezanost kriterijuma i indikatora sa ciljevima prostornog razvoja. Problem prepoznavanja ciljeva je posebna tema istraživanja i obuhvata razradu više nivoa ciljeva prostornog razvoja iz kojih treba da se identifikuju kriterijumi kao vrednosne kategorije i indikatori praćenja ostvarivanja ciljeva. U svetlu novijih promena u pristupu planiranju koje obeležavaju procesi globalizacije, uključivanja u evropske integracione procese, tranzicione promene institucionalnog i normativnog sistema, kao i suštinska primena koncepta održivog razvoja, ističe se zahtev za preispitivanje kriterijuma i indikatora u prostornom planiranju i prilagođavanje novim potrebama. iii U ovom radu, analizirani su kriterijumi u planiranju na osnovu fundamentalnih principa koji podupiru legitiman okvir prostornog razvoja u Srbiji. To su kriterijumi: prostorne integracije, demokratskih prava i javnog interesa, supsidijarnosti, participacije, optimizacije, prioritetnosti, nosećeg kapaciteta i predostrožnosti. Polazeći od toga da nacionalna, regionalna i lokalna zajednica dele zajedničku odgovornost za organizaciju, korišćenje, uređenje i zaštitu prostora, potrebno je da se utvrdi jedinstvo kriterijuma za usaglašavanje i koordinaciju prostornih planova. Na nacionalnom nivou definisani osnovni principi i instrumenti prenose glavnu obavezu na regionalnu i lokalnu zajednicu da uključe svoje posebne ciljeve i odrede specifična pravila upravljanja prostornim razvojem uz usklađivanje svih aktivnosti koje imaju prostorne implikacije. Ovaj zadatak podrazumeva koordinaciju različitih planskih nivoa, vertikalnu i horizontalnu povezanost prostornih i urbanističkih planova, po osnovu sadržaja, stepena razrade, uloge pojednih aktera i tretmana različitih prostorno relevantnih aktivnosti. Prvi korak za razvoj sistema indikatora je osmišljavanje ili izbor logične strukture/šeme po kojoj će indikatori biti organizovani. Traženje optimalnog načina kombinovanja indikatora, koji će biti referentan za sve ključne aspekte istraživačkog procesa, često je veći izazov od identifikovanja samih indikatora. U radu se opisuju tri pristupa za organizovanje indikatora, koja se obično koriste u prostornom planiranju i prostornim istraživanjima (problemski pristup, ciljni pristup i pristup održivosti), kao i osnovni postupak selekcije i ocenjivanja potencijalnih indikatora. Kada se govori o indikatorima, jedna od kritika prakse prostornog planiranja je da nema dovoljno planskih indikatora koji ukazuju na prostorne posledice i opravdanost investicionih poduhvata i njihovih ukupnih efekata na kvalitet življenja i razvoj društvene zajednice. Konvencionalni indikatori uglavnom se fokusiraju na jedan aspekt i prikazuju prostor kao nepovezane segmente (životna sredina, saobraćaj, zdravstvo, ekonomija i dr.). Uvažavajući iv podjednaku važnost svih ovih komponenti za razvoj zajednice, dobri indikatori su oni koji odražavaju povezanost prostornog, ekonomskog, envajromentalnog i socijalnog razvoja, odnosno odraz su preplitanja ovih oblasti a ne njihovog parcijalnog sagledavanja. Sledeći osnovne principe za uključivanje u evropske integracione procese, posebno je kod regionalnog nivoa planiranja bitno da se postigne usklađenost sa evropskim planskim dokumentima prostorne integracije. Pored toga, predlog sistema osnovnih indikatora predstavljao bi okvir za sistematizaciju i uključivanje posebnih indikatora, prema regionalnim ili lokalnim specifičnostima. Prihvatanje koncepta održivosti označilo je izvestan pomak u metodologiji planiranja, posebno na polju istraživanja instrumentarija za merenje napretka u pravcu održivosti. Potencira se potreba razvoja novih indikatora za ključne komponente na kojima se bazira koncept održivosti kao što su noseći kapacitet i potencijal zajednice - prirodni, humani i stvoreni (izgrađeni i finansijski). Na kraju rada daju se pravci poboljšanja indikatora prostornog razvoja, pri čemu se vidi korist u primeni dinamičkih sistema, za razumevanje povezanosti između elemenata sistema, merenja intenziteta uticaja, kao i prirodu uticaja koji su signal promena ili reakcija/odgovor na promene u načinu korišćenja, uređenja i zaštite prostora.

Criteria and indicators are used as a common means in almost all segments of spatial planning process and actions. Criteria, as reflections of social values, are primarily considered based on rules, standards and norms in organization, use, protection and development of space. Indicators are measurable features of spatial phenomena through which it is possible to monitor and control the processes and phenomena in space, as well as to assess the realization of the planning objectives and established criteria. The criteria and indicators applied in spatial plans, their objectivity, updateness and reliability actually reflect the development of spatial planning as a social practice, as well as discipline conceptually grounded on the scientific basis. As a social practice, spatial planning is prone to social and political changes, thus to the evaluation criteria for space. On the other hand, spatial planning is scientifically grounded in natural and humanistic sciences taking into account research methods and results of complex and numerous processes in space. Thus, in investigation of spatial development, and particularly in practical work – elaboration of spatial plans, themes of criteria and indicators are always topical and subject to re-examination. The attitude that 'we valuate what we measure and measuring what we value' shows dynamism of and inextricable link between these themes, which is a particular challenge in spatial planning. Changes in the system of values mark the changes in the planning model or even changes in relationship towards space through new planning paradigm in choosing the goals, priorities and roles of actors included in the planning process. The need for criteria derives from a normative power of spatial plan, which indirectly binds users of space and developers to observe the rules, specifying what can and what vi cannot be done in space. Norms are necessary because this legislative area and plenty of legal consequences (land expropriation, concessions, regime for space-use, construction requirements, inspection, sanctions, etc.) affect the private property and public rights, i.e. the realization of private and public interests. The objective of the research is to establish basic sets of harmonized criteria and indicators for spatial plans, so that these plans could be applicable and sufficiently coordinated for making planning decisions on the development and use of space. Theoretical starting point for the concept of criteria and indicators for spatial planning is explored within cause-and-effect relationships and processes through searching the universal values of spatial development. The paper singles out several aspects of natural, economic and social conditionality, from which the starting point for rules and criteria can be considered. The existence of some universal rules in time and space is explored, as well as diversity of rules in different social contexts. The link between criteria and indicators, on the one hand, and goals of planned development, on the other hand, is one of the major determinants in research. The issue of linking the goals is a specific theme of research and it includes the elaboration of several goals of spatial development from which criteria as value categories should be identified. In light of recent changes in the approach to planning marked by globalization processes, inclusion into integration processes, transitional changes of institutional and normative systems, as well as substantial implementation of the concept of sustainable development, the demand to re-examine criteria and indictors in spatial planning and to adapt them to new needs is highlighted. This paper analyzes criteria in planning based on fundamental principles supporting the legislative framework for and policy of spatial development in Serbia. These criteria include: spatial integrations, democratic rights and public interest, subsidiarity, participation, optimization, priorities, carrying capacity, as well as precaution. Starting from the fact that national, regional and local communities share common responsibility for organization, use, development and protection of space, it is necessary to determine the uniformity of criteria for harmonization and coordination of vii spatial plans. The main principles and instruments defined at the national level transfer to regional and local communities the main obligation to include specific goals and establish specific rules for managing the spatial development along with the harmonization of activities having spatial implications. This task implies the coordination between different levels of planning, vertical and horizontal link between spatial and urban plans on the basis of contents, the degree of elaboration, rule of certain actors and consideration of different spatially relevant activities. The first step in developing the system of indicators is to conceive or select logical structures/schemes according to which the indicators will be organized. Searching for an optimal way of combining the indicators that would be a referent way for all key aspects of research process, is often more challenging than the identification of indicators themselves. This paper describes three approaches to organizing the indicators usually used in spatial planning and spatial research (problem-based approach, target-based approach and sustainability approach), as well as the main method in selecting and assessing the potential indicators. As for indicators, one of criticism of the practice of spatial planning is that there are no enough indicators for planning which indicate spatial effects and justifiability of investment undertakings and their overall effects on the quality of life and development of local and/or regional communities. Conventional indicators are mainly focused on one aspect only and show the space as unconnected segments (the environment, traffic, health , economy, etc.). Taking into account the importance of all of these components for the development of community, the good indicators are those reflecting the connectivity between spatial, economic, environmental and social development, i.e. those reflecting the overlapping of these fields, as well as their partial consideration. Following the main principles of inclusion in European integration processes, it is particularly important for regional level of planning to achieve harmonization with European spatial planning documents. In addition, the proposal of the system of main indicators would provide a framework for systematization and inclusion of specific indicators according to regional or local specificities. The acceptance of the concept of sustainability has marked a certain step forward in the planning methodology, especially in the field of exploration of instruments for viii measuring progress towards the sustainability. This paper emphasizes the need for developing new indicators for key components on which the concept of sustainability is based, such as carrying capacity and community capital - the natural, human and created (built and financial) capital. Finally, the present paper gives directions for improvement of indicators for spatial development, whereby the benefit of implementing dynamic systems is made obvious, as well as the benefit for understanding the relationship between elements of the system, measuring the impact intensity, as well as nature of impacts that are signal of changes or reactions/response to changes in the way in which space is used, developed and protected.

Uloga i značaj planiranja infrastrukture u razvoju planinskog turizma u Srbiji

The role and importance of infrastructure planning in mountain tourism development in Serbia

Osnovni cilj disertacije je ispitivanje i definisanje međusobnih uslovljenosti, veza, značaja i uticaja planiranja infrastrukture i razvoja planinskog turizma, što bi omogućilo da se razviju metode za uspešnije sagledavanje procesa promena u prostoru i načini njihovog usmeravanja u željenom pravcu...

The main purpose of this dissertation is to examine and define the interrelated causation, connections, importance and influences of infrastructure planning and mountain tourism development, which would enable the development of methods for a more successful consideration of the process of changes in space and ways of directing them towards a desired course. By parallel analyses of the experiences in Serbia, the world and Europe, as well as of the similar experiences of the neighbouring countries, the proposed solutions tend to help the further work of experts, and of regional and local authorities and other stakeholders directly or indirectly involved in this field, with the aim of mountain tourism development in Serbia. The research covered several successively related parts: defining the basic theoretical grounds of the problem – general considerations of mountain areas, tourism, mountain tourism in particular, infrastructure systems and their planning, as well as development planning of tourist areas; an analysis of the most significant characteristics and interrelated similarities and differences of mountain tourism development in the world, in Europe, in neighbouring countries, starting from its history proceeding to the current situation and ending with the development trends, with a detailed consideration of the mountain areas of Kopaonik and Tara; an analysis of infrastructure capacity of the mountain areas of Serbia, with a detailed consideration of the areas of Kopaonik and Tara, on basis of which the conclusions were defined about the relationship between mountain tourism development and infrastructure capacity of mountain areas. Next, infrastructure planning was analysed with a view to mountain tourism development in strategic and planning documents in Serbia at the national level, including those covering the areas of Kopaonik and Tara; subsequently, the applied norms and standards for infrastructure capacity of mountain tourist areas were separately considered. The final part of the thesis considered the possibilities of defining the steps towards a directed and coordinated improvement of the situation in the examined area through specific suggestions within the planning process of sustainable mountain tourism and infrastructure planning with a view to mountain tourism development. The use of integral and comparative scientific method, as well as the analysis and synthesis methods and integral approach to problem solving throughout the research have confirmed the basic hypothesis that the directed, coordinated and efficient infrastructure planning is a powerful tool, which contributes to mountain tourism development, i.e. that the stated interrelations evidently confirm the possibility to promote and direct both mountain tourism development and spatial development as a whole by way of thoughtful planning and programming of infrastructure systems development. The research determined that the infrastructure capacity of mountain areas in Serbia is not at an adequate level, that the institutional coordination in directing the development of mountain tourist areas has been neglected, and that mountain tourism development in Serbia has not so far functioned as an integrating factor or driving force of local government development. The research has led to the following conclusions that have confirmed the secondary hypotheses: equipping areas with appropriate infrastructure is the prerequisite for sustainable mountain tourism development, i.e. appropriate planning and development of infrastructure systems has to be solely considered as an assumption and not as a consequence of the development of mountain tourist areas; the management of infrastructure systems needs to reflect a holistic consideration of planning and designing spaces without partial considerations of individual components or their planning as artificially separated parts and so infrastructure planning is one of the instruments of directing mountain tourism development and its cooperation with other development measures and instruments is necessary; infrastructure planning itself is not a sufficient condition for mountain tourism development, as it requires appropriate implementation and monitoring of the implementation of planning and programming solutions – consequences of an adequately and efficiently completed infrastructure planning and programming process, i.e. a successful implementation of plans and programmes is a specific realization of individual infrastructural objects, which involves the procedure of designing and building physical structures in space within a certain time period.

Analiza ponašanja grupe elastičnih moždanika kod spregnutih nosača od čelika i betona

The analysis of headed studs group behavior in composite steel-concrete beam

Diskontinualni podužni smičući spoj ostvaren grupama moždanika je jednostavno i široko rasprostranjeno rešenje za sprezanje čeličnih nosača i montažnih armiranobetonskih ploča. Ovaj rad analizira mogućnost primene grupa moždanika sa redukovanim rastojanjima između susednih moždanika u grupi. Osnovni cilj rada je da se istraži mogućnost smanjenja rastojanja između susednih moždanika u grupi u odnosu na minimalno propisana rastojanja. Smanjenje rastojanja između moždanika u grupi i dimenzija grupe, omogućava izvođenje manjeg otvora u armiranobetonskoj montažnoj ploči potrebnog za smeštaj moždanika. Prikazano je sopstveno eksperimentalno istraživanje nosivosti grupa moždanika, sprovedeno na Građevinskom fakultetu Univerziteta u Beogradu. Eksperimentalnim istraživanjem analizirana je mogućnost primene grupe moždanika kod spregnutih greda u zgradarstvu. Ispitana je nosivost, deformabilnost i ponašanje, podužnog smičućeg spoja ostvarenog grupama moždanika. Glavni parametri analizirani u radu su: raspored moždanika u grupi, orijentacija grupe moždanika u odnosu na pravac podužne sile smicanja i međusobno rastojanje moždanika. Istraživanjem je obuhvaćeno pet različitih dispozicija grupa od četiri elastična moždanika sa glavom, kod kojih su međusobna rastojanja manja od minimalno propisanih rastojanja u Evrokodu 4. Cilj istraživanja je i da se utvrdi kako smanjenje minimalnih propisanih rastojanja između moždanika utiče na ponašanje, odnosno nosivost, duktilnost i ukupne deformacije podužnog smičućeg spoja. Korišćeni materijali, polazne pretpostavke i postupak ispitivanja su u skladu sa Evrokodom 4. Metodom konačnih elemenata simulirano je eksperimentalno istraživanje a kalibrisan numerički model sa eksperimentom je poslužio za izvođenje zaključaka o ponašanju veze ostvarene grupom moždanika sa glavom. Uočeni su i definisani modeli loma koji se mogu javiti u podužnim smičućim spojevima, formiranim grupama moždanika. Na uočenim modelima loma definisana su granična stanja nosivosti grupe moždanika. iv Pomoću numeričkih modela urađena je i parametarska analiza koja je obuhvatila različite prečnike i grupe moždanika. Na osnovu dobijenih rezultata izvedene su preporuke za određivanje nosivosti grupe moždanika kada su rastojanja između susednih moždanika manja od propisanih. Predložen je redukcioni koeficijent za određivanje nosivosti grupe moždanika. Izvedene preporuke važe za smičuće spojeve spregnutih greda od čelika i betona u objekatima visokogradnje.

Discontinuous shear connection with groups of headed studs is simple and widespread solution for connection between steel beam and precast concrete element. This thesis analyzes the possible applications of headed studs group with reduced distances between adjacent headed studs in the group. The main objective of this study was to investigate the possibility of reducing the spacing between adjacent headed studs in the group compared to the minimum required in Eurocode 4. Reducing the distance between the headed studs in the group and the dimensions of the group, would allow construction of a smaller hole in the reinforced concrete precast plate needed to accommodate the headed studs. The paper presents the results of the experimental research conducted on push-out tests at the Faculty of Civil Engineering at the University of Belgrade. Throughout the experiment there has been analyzed the possibility of using the headed studs group in composite beams for buildings. The capacity, deformability and behavior of shear connection with grouped headed studs was investigated (analyzed). A shape of group arrangement along with its orientation to the applied load and distance between the studs were variables considered. The study includes five different groups of four headed studs, with the distance between headed studs less than the minimum distances required in Eurocode 4. The aim of the research is to determine how the reduce of the minimum required distance between the headed studs affects to the behavior, shear capacity, ductility and total longitudinal shear deformation of the shear connection. The materials, initial assumptions and test set up are in accordance with Eurocode 4. The FEM model is used to simulate the experiment. Calibrated FEM models with push-out tests were used to draw conclusions about the behavior of shear connection with group of headed studs. The fracture models which can occur in longitudinal shear connection with headed studs group were identified and defined in the paper. Ultimate limit state for headed stud group based on the fracture models is defined. Parametric analysis, which included a models with different diameters of headed studs and layout of groups were performed by numerical models. vi Based on the results, the recommendations were derived for determining the shear capacity of the headed studs group, when the distance between studs is less than required by Code. The reduction coefficient was suggested to determine the shear capacity of the headed studs group. Derived recommendations can be applied to shear connections in composite steel-concrete beams applied in buildings.

Vodni potencijal i hidrogeografska rejonizacija Valjevskih planina

Valjevske planine su deo jedinstvenog venca Podrinjsko–valjevskih planina, koji predstavlja istaknutu crtu reljefa zapadne Srbije. Prostiru se u smeru zapad–severozapad – istok–jugoistok, od prevoja Proslop, koji odvaja Sokolske planine (podrinjski niz) od Medvednika (valjevski niz) do Prostruge, na krajnjim severoistočnim obroncima Rajca iznad Boljkovačkog raseda. Valjevske planine čine: Medvednik, Jablanik, Povlen, Maglješ, Maljen, Suvobor i Rajac. Prirodna raznolikost Valjevskih planina od litološke građe, preko klimatskih odlika do biljnog pokrivača rezultirala je raznovrsnošću voda i njihovih pojava. Time je inicirano ovo istraživanje, sa ciljem detaljnog upoznavanja osobenosti – bogatstva i raznovrsnosti površinskih voda ovog kraja i njihovih odnosa, kao i prirodno–geografskih uslova koji su ih oblikovali. Hidrogeografska granica istraživanog područja je obuhvatila 11 glavnih slivova koji nastaju na vencu Valjevskih planina: Ljuboviđu, Trešnjicu i Rogačicu – pritoke Drine; Skrapež, Kamenicu i Čemernicu sa Dičinom – pritoke Zapadne Morave; Ribnicu, Lepenicu, Gradac, Jablanicu i Obnicu – pritoke Kolubare. U radu je izdvojena i oblast Valjevskih planina – kao uža granica, koja je određena na osnovu tektonskih, litoloških i hipsometrijskih pokazatelja. U cilju upoznavanja prirodnog okvira Valjevskih planina analizirana je odgovarajuća literatura o najvažnijim fizičko–geografskim činiocima. Periodično su vršeni i obilasci terena – određenih lokaliteta za koje se pretpostavljalo da mogu prikazati bitne elemente prirodne sredine, u njihovim relacijama sa glavnim pojavama površinskih voda. Na osnovu topografskih karata (1:25000) digitalizovana je kompletna hidrografska mreža slivova koji nastaju na Valjevskim planinama (rečna mreža i izvori); sa osnovnih geoloških karata (1:100000) iscrtani su svi litološki poligoni (kasnije grupisani u 6 klasa); sa pedoloških karata (1:50000) preneseni su svi zemljišni poligoni1. Potom je iz postojećeg digitalnog modela reljefa (DEM100) izdvojen prostor slivova Valjevskih planina, a za istu površinu i podaci o biljnom pokrivaču na osnovu CORINE Land Cover baze podataka. Hidrološki i klimatološki podaci su sabirani i uređivani za pedesetogodišnji period 1961–2010. godina. Osnovu hidroloških podataka činili su nizovi srednjih mesečnih i godišnjih proticaja, kao i minimalnih i maksimalnih godišnjih vrednosti. Padavine su jedan od osnovnih elemenata potreban u svim hidrološkim analizama. U cilju obezebeđivanja svrsishodnijih podataka, izvršena je regresiona analiza – zavisnosti padavina od nadmorske visine, koja je poslužila za podelu istraživanog prostora na četiri celine, nakon čega je izvršena interpolacija padavina. Time je dobijena srednja vrednost padavina za svako jedinično polje ili bilo koji izdvojeni poligon na istraživanom području. Ti podaci su poslužili i za određivanje vrednosti specifičnog oticaja za četiri neizučena sliva: sva tri drinska – Ljuboviđu, Trešnjicu i Rogačicu i za kolubarsku Lepenicu. Specifični oticaj je izračunat na osnovu modela, u čijoj formuli su tri nezavisne varijable: godišnje vrednosti temperatura i padavina, kao i udeo metamorfnih i magmatskih stena. Time je bilo moguće izračunati vrednosti srednjeg specifičnog oticaja za spomenute slivove, ali i za svaki izabrani poligon na istraživanoj oblasti. Podaci su poslužili za utvrđivanje hidrometrijskih karakteristika glavnih tokova i morfometrijskih pokazatelja njihovih slivova, od najmanjih po površini – Trešnjice i Ribnice do najvećih Skrapeža i Čemernice. Od pokazatelja je izdvojena gustina rečne mreže. Ubedljivo najmanju gustinu rečne mreže ima reka Lepenica sa 0,65 km/km2, a najveću reka Kamenica sa 2,71 km/km2. Izvršena je kompleksna hidrološka analiza svih 11 tokova, koja je pokazala da najveću vodnost ima sliv Gradca sa specifičnim oticajem od 18,28 l/s/km2, a najmanju Čemernica sa 6,45 l/s/km2. Gradac ima i najveći koeficijent oticaja od 0,52, a slede ga Drinine pritoke. Najmanje koeficijente oticaja imaju Čemernica sa 0,26, a potom Lepenica i Skrapež sa 0,27. S obzirom 1 Digitalizacija je vršena u programu ARC GIS. na to da sve posmatrane reke Valjevskih planina imaju maksimalne proticaje u martu, a minimalne u septembru i avgustu, pojednostavljeno je konstatovano da je njihov režim, prema klasifikaciji S. Ilešiča (1947), najbliži rekama pluvio– nivalnog režima balkanske – umereno–kontinentalne varijante. Hidrološka analiza je pokazala da vodni potencijal – količina površinske vode koja godišnje otekne slivovima Valjevskih planina iznosi 0,782 km3 vode. Od toga sama oblast Valjevskih planina – ima 0,334 km3 površinske vode. Gledano po visinskim zonama – najviše površinske vode na ovom prostoru otekne iz zone 500–600 m – 0,1451 km3. Vodni potencijal Valjevskih planina upotpunjen je objektima hidrološkog nasleđa Srbije. Njihova brojnost (21), ali još više raznolikost, svedoče o izuzetnom vodnom bogatstvu ovog kraja: izuzetna kraška vrela koja odlikuju osim vrednosti kao resursa pijaće vode i istaknute naučne i ekološke vrednosti; vodni rezervati koji potvrđuju izuzetnu važnost očuvanja voda i prirodnog okruženja delova Valjevskih planina u kojima su razvijeni; vodopadi, slapovi i reke ponornice – jedinstveni su ukrasi i fenomeni Valjevskog krasa. Njima treba pridodati izuzetne vodne pojave – potencijalne objekte hidrološkog nasleđa: Crvenbreško vrelo, vodopad na Ikonića reci, potopljenu vrtaču u selu Brežđe, Ključka vrela, vodopade i slapove u dolini Tribuće... kao i mnoge neotkrivene. Slivovi Valjevskih planina su analizirani i sa aspekta uticaja fizičko–geografskih činilaca na njihovu vodnost i hidrometrijske (morfometrijske) odlike – gustinu rečne mreže. Osim poznatih veza, nekih pozitivnih i negativnih relacija, konstatovano je da su uticaji složeni te da je veoma teško izdvojiti uticaj i meru jednog od njih. Hidrogeografska rejonizacija je bila sintezni cilj istraživanja, kojoj je prethodilo upoznavanje teorijsko–metodoloških osnova fizičko–geografskog rejoniranja. Sliv se logično nametnuo kao osnovna jedinica i element u rejoniranju, a kao glavni zadatak – izbor odgovarajućih pokazatelja ili kriterijuma rejonizacije. Iz formirane baze podataka (osnova GIS–a) podaci su grupisani – po slivovima kao hidrološki (specifični oticaj, padavine, visina oticaja, koeficijent oticaja i isparavanje), fizičko–geografski i hidrometrijski. Tako su izabrani i odgovarajući pokazatelji kao i tri vida hidrogeografske rejonizacije. Primenjena je klasterska analiza, koja je trebalo da ukaže na (statističke) sličnosti i različitosti između slivova na osnovu čega bi bilo izvršeno njihovo grupisanje. Rezultati su uređeni i podvrgnuti teorijskoj analizi. Prostor Valjevskih planina je hidrografski izdeljen – površinske vode prirodno otiču u tri veća sliva: kolubarski, zapadnomoravski i drinski. Detaljnim istraživanjem vodnih odlika i fizičko–geografskih uslova, nastojalo se utvrditi da li i kakve hidrogeografske veze u prirodi postoje van ovih očiglednih. Neki slivovi su pokazivali znatnu sličnost i pravilnost pojavljivanja u većini analiza, poput Lepenice–Obnice i Jablanice–Ribnice. Neki su se samostalno izdvajali – Gradac po svojoj vodnosti ili Kamenica i Trešnjica po hidrometrijskim pokazateljima. Drinski slivovi su pokazivali znatnu međusobnu sličnost, a u nekim analizama su prilazili grupama kolubarskih... Ipak, ovo istraživanje je nagovestilo da „prirodna hidrogeografska rejonizacija“ Valjevskih planina nije slučajna. Istraživane hidrogeografske i hidrološke odlike najsličnije su između slivova u okviru prirodno izdvojenih grupa: drinske, zapadnomoravske i kolubarske. Ukoliko ovaj rad posluži kao jedan od putokaza ka dubljem upoznavanju zakonitosti u hidrogeografskim relacijama Valjevskih planina, moglo bi se reći i da je njegov cilj ostvaren.

The Valjevo mountain range is part of a unique range of Podrinje–Valjevo Mountains, which at the same time represents a prominent characteristic of western Serbia relief. Valjevo mountains stretch in the west–northwest – east–southeast direction, from Proslop mountain pass, which separates Sokolske mountains (Podrinje range) from Medvednik (Valjevo range), all the way to Prostruga at the farthest northeast slopes of Rajac mountain above Boljkovački fault. Valjevo mountains include Medvednik, Jablanik, Povlen, Maglješ, Maljen, Suvobor and Rajac. The natural diversity of Valjevo mountains including their lithological composition, climatic features and plant cover has resulted in a variety of waters and their phenomena. This fact initiated a detailed research of the richness and diversity of surface waters in this area and their relationships, as well as of natural and geographical conditions that formed these phenomena. Hydrogeographic boundaries of the research area included 11 major basins in the Valjevo mountain range: Ljuboviđa, Trešnjica and Rogačica – tributaries of the Drina river; Skrapež, Kamenica and Čemernica with Dičina – tributaries of the Western Morava; and Ribnica, Lepenica, Gradac, Jablanica and Obnica – tributaries of Kolubara. This paper also presents the area of Valjevo mountains as a rather narrow belt identified on the basis of tectonic, lithological and hypsometrical indicators. In order to introduce the physical–geographical framework of Valjevo mountains this paper analyzes the relevant literature on the most important physical– geographical factors. Periodic field surveys have also been carried out including the visits to specific sites that are supposed to evidence the essential elements of environment in their relations with the major phenomena of surface waters. Based on topographic maps (1: 25000), a complete hydrographic network of basins originating in Valjevo mountains (river network and sources) was digitalized, the basic geological maps (1: 100000) were used to plot all the lithological polygons (later grouped into 6 classes), and the paedological maps (1: 50000) were used to plot all soil polygons. After that the existing digital model of relief (DEM100) was used to mark the area of Valjevo mountains basins, along with data on the plant cover according to the CORINE Land Cover database. Hydrological and climatological data have been collected and edited for the period of fifty years 1961–2010. The basis of hydrological data consisted of the series of average monthly and annual flow rates, as well as the minimum and maximum annual values. Precipitation is one of the basic elements required in all hydrological analyses, and in order to obtain the most meaningful data, the regression analysis has been carried out, which showed the relation between the precipitation and altitude, and served the purpose of dividing the research area into four units, after which the interpolation of precipitation was performed. This provided the average value of precipitation for each unit field or any separate polygon of the researched area. Those data were used to determine the value of specific runoff for the four unresearched basins: all three Drina basins – Ljuboviđa, Trešnjica and Rogačica, and Lepenica in the Kolubara basin. The specific runoff was calculated according to the model with the formula including three independent variables: annual values of temperature and precipitation, as well as the ratio of metamorphic and igneous rocks. This enabled the calculation of the average specific runoff for these basins, but also for each selected polygon of the researched area. Data were used to determine the hydrometric characteristics of major water flows and morphometric indicators of their basins, from the smallest on the surface – Trešnjica and Ribnica, to the largest Skrapež and Čemernica. The singled out indicator was density of the river network. By far the lowest density of the river network was in Lepenica river with 0.65 km/km2, and the highest in Kamenica river with 2.71 km/km2. The complex hydrological analysis of all 11 water courses has shown the maximum water level in Gradac basin with its specific runoff of 18.28 l/s/km2, and the smallest in Čemernica with only 6.45 l/s/ km2. Gradac has the highest runoff coefficient of 0.52, followed by the tributaries of the Drina river. The lowest runoff coefficient is in Čemernica with 0.26, followed by Lepenica and Skrapež with 0.27. Given the fact that all researched Valjevo mountains rivers had maximum flow rates in March, and minimum in September and August, it was simply noted that their regime, according to the classification by S. Ilešič (1947), was the nearest to the regimes of the rivers in the pluvio–nival regime of the Balkans moderate continental variable. The hydrological analysis has shown the water potential of 0.782 km3, that is, the amount of surface water annually flowing in the basins of Valjevo mountains,whereas the area of Valjevo mountains alone has 0.334 km3 of surface water. Judged by the altitudinal belts, the most surface water in this area, precisely 0.1451 km3, runs off from the zone at 500–600 m of altitude. Water potential of Valjevo mountains is complemented by the hydrological heritage sites of Serbia. Their number (21), but even more variety, evidence the extraordinary water resources of the region: exceptional karst springs, which are not only the source of drinking water, but also the prominent values in terms of science and ecology; water reserves which confirm the exceptional importance of water and natural environment conservation of the parts of Valjevo mountains where these resources had developed; waterfalls and subterranean rivers (lost rivers), and the unique characteristics and phenomena of Valjevo karst region. They should be added by the outstanding water phenomena – potential sites of hydrological heritage: Crvenbreško spring, waterfall on the Ikonića river, flooded sinkhole in the village Brežđe, Ključka springs, waterfalls in the valley of Tribuća, and many other yet undiscovered. The basins of Valjevo mountains were analyzed from the aspect of physical and geographical factors influencing their water resources and hydrometric (morphometric) qualities – density of the river network. In addition to the known relations, some positive and some negative, it was determined that the impacts were rather complex and that was very difficult to isolate the impact and measure one of them. Hydrographic zoning was the synthesizing aim of the research, which was preceded by exploring the theoretical and methodological bases of physical– geographical zoning. The basin logically emerged as the basic unit and an element of the zoning, and the main task was the selection of appropriate indicators or zoning criteria. The GIS based data were further grouped according to the basins as hydrological (specific runoff, precipitation, the amount of runoff, runoff coefficient and evaporation), physical–geographical and hydrometric. In this way the appropriate indicators and three types of hydrogeographical zoning were chosen. The cluster analysis was applied, which was supposed to show the (statistical) similarities and differences between the basins, on the basis of which the basins grouping should be done. The results were obtained and subjected to theoretical analysis. The area of Valjevo mountains is hydrographically fragmented, and the surface waters naturally flow into three major basins: Kolubara, West Morava and Drina basins. A detailed research of water characteristics and physical–geographical conditions of the area was conducted in order to determine whether and what hydrogeographic relations existed in nature besides the obvious ones. Some basins showed significant similarity and regularity of occurrence in most analyses, such as Lepenicа–Obnica and Jablanica–Ribnica basins. Other basins showed unique characteristics, such as Gradac with its flows, or Kamenica and Trešnjica according to their hydrometrical indicators. Drina river basins showed considerable similarity, and in some analyses were similar to the groups of Kolubara basins. However, the research indicated that "natural hydrographic zoning" of Valjevo mountains was not merely accidental. The researched hydrogeographic and hydrological characteristics proved the most similar in the basins within the naturally distinguished groups: Drina, West Morava and Kolubara basins. If this paper served as one of the guidelines towards a deeper understanding of the hydrogeographical relations in the Valjevo mountains, it should be said that the main intention has been achieved.

Geoekološka evaluacija prirodnih potencijala Ravne planine i Paljanske kotline u funkciji održivog razvoja

Geoecological evaluation of natural potentials of the Ravna mountain and Pale valley in the function of sustainable development

U radu je izvršena identifikacija i determinacija pogodnosti prirodnih potencijala za razvoj pojedinih grana privrede na prostoru Ravne planine i Paljanske kotline. Upotrebom metoda geoekološke evaluacije, među kojim izdvajamo integraciju modela analitičkog hijerarhijskog procesa (AHP) i geografskog informacionog sistema (GIS), dobijeni su postojani rezultati i potvrđeno je da prirodni potencijali imaju dominantan uticaj na razvoj privrednih djelatnosti kao što su poljoprivreda, šumarstvo i turizam. Za provjeru tačnosti težinskih koeficijenata dobijenih AHP metodom korišćen je stepen konzistentnosti matrice (CR). Osnovni kriterijumi na osnovu kojih je izvršena evaluacija su: reljef, klima, hidrološke, pedološke i biogeografske karakteristike. Na osnovu ovih kriterijuma izveden je veći broj podkriterijuma korišćenih u postupku evaluacije, a njihov broj je varirao ovisno o namjeni evaluacije. Najviše podkriterijuma izdvojeno je u postupku evaluacije prirodnih potencijala za potrebe poljoprivrede (petnaest), a najmanje za potrebe šumarstva (osam). Za potrebe turizma korišćeno je deset podkriterijuma, od kojih dva socioekonomska. Sve fizičkogeografske komponente u radu analizirane su pojedinačno i kompletno. U osnovi evaluacija je podrazumijevala analizu fizičkogeografskih elemenata, odnosa i veza, pri čemu su geokomponente, procesi i pojave tretirani u razvijenom obliku. Za racionalno korišćenje prostora u svrhu poljoprivrede, šumarstva, i turizma izvršena je funkcionalna evaluacija, a potom i sinteza dobijenih rezultata. Nakon provedbe funkcionalne evaluacije urađena je analiza stabilnosti rješenja na promjene pojedinih ulaznih podataka pomoću metode numeričke inkrementalne analize koja je pokazala visoku stabilnost dobijenih rezultata, naročito u pogledu turizma. Kreirane su karte pogodnosti proučavanog prostora za potrebe poljoprivrede, šumarstva i turizma, a u konačnici i sintezna karta kojom su kvalitativno identifikovane površine najboljih fizičkogeografskih potencijala svih analiziranih djelatnosti. Evaluacija je pokazala različit stepen pogodnosti za pojedine privredne djelatnosti, pri čemu su zone šumarstva i rekreativnog turizma dobile najviše ocjene i najveći prostorni obuhvat, dok su zone povoljne za poljoprivredu zastupljene sa najmanjim udjelom. Korišćena metodologija pokazala je da se najpogodnije prostorne cjeline za šumarstvo i rekreativni turizam teritorijalno poklapaju sa zaštićenim zonama šuma planinskog javora i atraktivnim rekreativnim površinama na Ravnoj planini, dok se poljoprivredno najvredniji prostori nalaze na hipsometrijski nižim terenima, uz riječne doline. U postupku evaluacije izdvojene su i eliminatorne površine kojima su pojedini dijelovi prostora izuzeti iz upotrebe zbog: naseljenosti i primarne funkcije stanovanja, infrastrukturnog korišćenja prostora, miniranih površina, ali i usljed specifičnosti fizičkogeografskih odlika prostora...

The research carried out in this thesis offers an identification and evaluation of the Ravna Mountain and Pale Valley natural potentials, for the purpose of development of certain economic sectors. Applying relevant geoecological evaluation methods, i.e. Analytic Hierarchy Process (AHP) and Geographical Information System (GIS) integratively provided reliable results, and it has been shown that natural potentials predominantly influence the development of such economic sectors as agriculture, forestry and tourism. The matrix Consistency Ratio (CR) was used for checking the validity of parameters obtained by AHP methodology. The evaluation in the research has been carried out on the basis of several criteria: relief, climate, hydrological, pedological and biogeographical characteristics. The research also implied certain sub-criteria derived out of the above-mentioned basic ones, while their application varied depending on the evaluative purpose. Most sub-criteria were derived for the evaluation of agricultural natural potentials (15), the least for forestry evaluation (8). Ten sub-criteria, two of them being socioeconomic, were used for evaluation of tourism. All physical-geographical parameters in the thesis were first analyzed separately and then as a whole. Basically, the evaluation implied analysis of physical-geographical elements and their interrelatedness, the relevant geocomponents, processes and phenomena being treated in their developed form. For the purpose of efficient use of the land in agriculture, forestry and tourism, the research first relied on functional evaluation and then synthesis of obtained results. After functional evaluation, the research focused on the analysis of reliability of methods related to changes of some input parameters, such as Numerical Incremental Analysis which have shown that obtained results are highly reliable, especially in domain of tourism evaluation. Finally, the thesis provides the maps offering the evaluation of the researched area sustainability in domains of agriculture, forestry and tourism, along with the overall map offering qualitative identification of areas most suitable in the context of physical-geographical potentials for all analyzed economic sectors. The evaluation has shown the difference in degree of suitability of the relevant economic sectors: while sectors of forestry and recreational tourism have proved to be most suitable and encompass wildest area, agricultural sector has proved to be the least suitable. The methodology used has shown that the most suitable areas in domain of forestry and recreational tourism territorially match with protected areas of Hildreich’s Maple and attractive recreational areas on Ravna planina, while agriculturally most suitable areas are located in lower areas, mostly along riversides. The process of evaluation also singled out certain areas unsuitable for the purpose of sustainable development, primarily due to residential character, infrastructure, mined areas but also due to physical-geographical specificities of the area itself...

Geografske determinante regionalnog razvoja Vojvodine

Geographical determinants of the regional development of Vojvodina

Problem regionalnog razvoja i regionalnih neravnomernosti u Srbiji je veoma izražen, i najveći je u Evropi. Konceptu regionalnog razvoja se tokom prethodnih decenija nije pridavao dovoljan značaj, i ova vrsta razvoja se nije po- smatrala kao integralni deo ukupnog društveno-ekonomskog razvoja. Proces tranzicije u Republici Srbiji samo je pogoršao već ionako teško stanje u poje- dinim područjima, još više produbio regionalne nejednakosti i usporio ceo proces regionalnog razvoja određenih područja Srbije. Koncentracija ekonomske aktivnosti u prostoru sve je izraženija pojava. Bilo da se posmatra globalni ni- vo, bilo da je predmet analize prostor unutar pojedinačnih nacionalnih privre- da, uočava se da određeni delovi teritorija mnogo brže napreduju u odnosu na druge. Ruralna područja, nekada osnovni nosioci razvoja, danas predstavljaju naj- siromašnije oblasti Republike Srbije sa izraženim depopulacionim kretanji- ma. Veoma izražene migracije selo-grad ostavljaju ruralna područja bez prisu- stva radno aktivnog stanovništva pa samim tim bez ikakvih mogućnosti za po- boljšanje postojeće situacije i celovitijeg regionalnog razvoja tih područja. Sa druge strane, devastirana područja nastala tokom tranzicionog perioda predsta- vljaju nekadašnje razvijene industrijske centre, u kojim je usled propadanja pri- vrede došlo do naglog pogoršanja celokupne društveno-ekonomske situacije. Tako danas u Republici Srbiji imamo grad Beograd i Autonomnu Pokrajinu Voj- vodinu, koji se prema svim pokazateljima razvijenosti nalaze visoko iznad osta- lih regiona, pa je i priliv stanovništva u njima najveći, dok se situacija u ostalim delovima Srbije neprekidno pogoršava, prevashodno usled demograf- skog pražnjenja. Negativne stope prirodnog priraštaja u čitavoj Srbiji predsta- vljaju veliki problem koji preti da ugrozi budućnost razvoja Srbije. Zakonom o regionalizaciji Republika Srbija podeljena je na pet stati- stičkih, makroregiona: region Vojvodina, region Grad Beograd, region Šumadija i Zapadna Srbija, region Južna i Istočna Srbija, i region Kosovo i Metohija. Ovom podelom omogućuje se korišćenje predpristupnih fondova Evropske Unije, u kojoj se regionalnom razvoju posvećuje veoma veliki značaj i na kome se odvija veći deo saradnje, ali što je još bitnije efikasnije sagledavanje geoekonomskog položaja pojedinih regiona i upravljanje regionalnim razvojem u cilju smanjenja regionalnih neravnomernosti. Postojeće regionalne nejednakosti imaju određeni uticaj na ukupne dru- štveno ekonomske performanse nacionalne privrede. Proces regionalnog razvo- ja i privrednog rasta, koji se odvija u uslovima globalne ekonomije nije jednako raspoređen na sve regione unutar nacionalne ekonomije te kao takav utiče na ni- vo postojećih regionalnih nejednakosti. U radu će se analizirati koncept regio- nalne konvergencije/divergencije unutar nacionalne ekonomije, a istovremeno će se istražiti dinamika rasta regiona koji se nalaze na različitim nivoima ekonomske i prostorne razvijenosti. Cilj predviđenog istraživanja u doktorskoj disertaciji je da se u skladu sa savremenim potrebama i zadacima istraživanja geoekonomskog položaja i geo- prostora, koji se svodi na analizu prostora (istraživanje zakonitosti u razvoju regionalnih struktura), ocenu prostora s društveno korisnog gledišta (uklju- čujući i budući razvoj) i ukazivanje na alternativne smerove regionalnog razvoja kao osnove za svrsishodnu razvojnu nacionalnu politiku i prostorno planiranje, izvrši identifikovanje, sagledavanje i pruži naučno objašnjenje problema veza- nih za regionalni razvoj, prostorno-funkcionalne odnose u Vojvodini, odnosno da se determiniše njihov model. Pod tim se podrazumeva strateško opredeljenje Srbije da razvije privredu zasnovanu na znanju, konkurentnosti i socijalnoj od- govornosti države. Naučnim objašnjenjem relevantnih faktora i definisanjem ge- oekonomskog položaja Vojvodine nameće se zadatak provere mogućnosti predviđa- nja budućeg regionalnog razvoja ove srpske pokrajine, i uticaja regionalnog razvo- ja Vojvodine na celokupni privredni rast i regionalni razvoj Republike Srbije. Rezultati rada treba da daju odgovor na pitanje u kojoj meri su Vojvodina i njeni subsistemi razvijeni da bi u skoroj budućnosti participirali u procesima regionalne i transgranične saradnje u Jugoistočnoj Evropi. Ovim radom će se ste- ći nova saznanja i izvući odgovarajuće pouke za Srbiju, koja kasni u procesu tran- zicije, i sagledati mogućnosti unapređenja obrazovne, naučne, političke i eko- nomske saradnje između naše zemlje i sveta, koja može doprineti efikasnijem i bez- bolnijem sprovođenju preostalih reformi u regionalnom razvoju Republike Srbije.

The problem of regional development and regional imbalances occurs very frequently in Serbia and is the biggest one in Europe. The concept of regional development has been underestimated over the past few decades and this kind of development hasn’t been considered as the integral part of the whole socio-economic development. The process of transition in the Republic of Serbia only made the already difficult situation worse in certain areas, intensified regional imbalances even more, and also slowed down the whole process of regional development of those areas in Serbia. The concentration of economic activities in space is becoming higher. Whether global level is regarded, or whether the object of the analysis is the area inside individual national economies, it is noticed that certain parts of territories make much more progress in regard to the others. Rural areas, which were the main driving forces of development long time ago, are nowadays the poorest regions of the Republic of Serbia with intensified depopulation movements. Extremely frequent migrations from villages to cities result in the absence of gainfully employed population and therefore without any possibilities for improving the current situation as well as the whole regional development of those areas. On the other hand, devastated areas as a consequence of transitional period are former developed industrial centers, where due to the decline of economy the whole socio-economic situation suddenly became worse. Therefore, Belgrade and the Autonomous Province of Vojvodina in the Republic of Serbia are nowadays far above the other regions considering all indicators of development, as a result of which their population influx is the highest one, while situation in other parts of Serbia is constantly becoming worse, primarily due to demographic abandonment. Negative rates of population growth all over Serbia are a big problem which may jeopardize the future of its development. According to the Law on Regional Development of the Republic of Serbia, the country is divided into five statistical macro regions: the region of Vojvodina, the region of Belgrade, the region of Šumadija and Western Serbia, the region of Southern and Eastern Serbia, and the region of Kosovo and Metohija. This division enables the use of pre-accession funds of European Union where regional development is really significant and where the greater part of cooperation takes place, but the more important fact is that it enables effective consideration of geo-economic position of certain regions and the management of regional development aiming at decrease in regional imbalances. Current regional imbalances have a certain impact on the whole socio-economic performances of national economy. The process of regional development and economic growth which occurs in conditions of global economy is not evenly disposed in all regions inside national economy, and as such it influences the level of current regional imbalances. This paper will analyse the concept of regional convergence/divergence inside national economy and at the same time investigate dynamics of the growth of regions which are on different levels of economic and spatial development. Considering contemporary needs and tasks of investigating geo-economic position and geo-space which embraces the analysis of space (investigating regularities within development of regional structures), estimation of space from the point of social aspect (including future development as well) and emphasizing alternative directions of regional development as the basis for appropriate development national politics and spatial planning, the aim of this research in doctoral dissertation is to identify, consider and scientifically explain problems concerning regional development, spatio-functional relations in Vojvodina, namely the aim is to determine their model. It implies strategic determination of Serbia to develop economy on the basis of knowledge, competitiveness and social responsibility of the country. Scientific explanation of relevant factors and defining geo-economic position of Vojvodina imposes the task of examining the possibilities of predicting future regional development of this Serbian province, and the influences of the regional development of Vojvodina on the whole economic growth and regional development of the Republic of Serbia. The results should answer the question to which extent Vojvodina and its subsystems are developed in order to participate in the processes of regional and transboundary cooperation in South-Eastern Europe in the near future. This paper will provide new findings and appropriate morals for Serbia which is late in the process of transition, and also consider possibilities for improving educational, scientific, political and economic cooperation between our country and the world which can contribute to more effective and painless conduction of remaining reforms in the regional development of the Republic of Serbia.

Niskociklični zamor kod jednoaksijalnog naprezanja dampera-apsorbera seizmičke energije sistema DC 90

Low-cycling fatigue of a damper-seismic energy absorber of DC-90 system under uni-axial stress

Cilj istraživanja je da se na osnovu teorije mehanike loma kod niskocikličnog naprezanja, fizičko-hemijske strukture čelika od kojih se izrađuje konstrukcija dampera-apsorbera seizmičke energije i mnogobrojnih rezultata modelskih istraživanja i ispitivanja na modelima i objektima, razume ponašanje, otkriju zavisnosti bitne za definisanje matematičkog modela za praktičnu primenu i dalje inoviranje uređaja za kontrolu histerezisnog ponašanja. Osim toga neophodno je iznaći stvarnu zavisnost akumulirane dilatacije u funkciji broja ciklusa kod dampera DC 90 i drugih elemenata konstrukcije, jer ovu oblast malog broja ciklusa ne pokrivaju dovoljno tačno postojeće relacije i poznate istražene zavisnosti. Ponašanje materijala u plastičnom stanju je definisano sa tri osobine: uslov tečenja (yelding condition), zakon tečenja (a flow rule) i zakon ojačanja (a hardening rule) materijala. Glavni cilj ove disertacije je da utvrdi uticaj broja cilusa i akumuliranih dilatacija, zamora u polju malog broja ciklusa, na konstruisanje dampera Sistema DC 90. Ova zavisnost se pre svega utvrđuje eksperimentalnim istraživanjima na osnovu kojih se formira numerički model ili se koriguju postojeće teoretske pretpostavke. Predmet istraživanja Usled cikličnog opterećenja, pri dejstvu zemljotresa, kod ugrađenih dampera sistema DC 90 dolazi do naprezanja u uslovima niskocikličnog zamora materijala. Naponi prelaze granicu tečenja, materijal može da izdrži mali broj ciklusa, i vrlo je važno odrediti broj ciklusa koji dovodi do konačnog kolapsa dampera. Pored toga, potrebno je definisati model za projektovanje željenog histerezisnog dijagrama dampera- apsorbera seizmičke energije sistema DC 90 pod niskocikličnim jednoaksijalnim naprezanjem. b. Naučne metode istraživanja Osnovna metoda istraživanja je analitička, bazirana na principima mehanike loma i mehanike oštećenja materijala. Urađen je odgovarajući broj eksperimenata kako u laboratoriji, tako i na terenu. Primenjene su i metode statističke obrade eksperimentalnih rezultata istraživanja, a korišćene su i numeričke metode proračuna. Eksperimentalna istraživanja običnih uzoraka od čelika S235, u polju malog broja ciklusa (LCF-Low Cycling Fatigue), kao i dinamička testiranja dampera tipa Canada HQl, Canada HQ Royal, Mionica i drugih izvršena su u laboratorijama Građevinskog fakulteta u Ljubljani, Laboratoriji Instituta za seizmičko inženjerstvo i inženjersku seizmologiju IZIIS u Skoplju, Laboratoriji Vojnotehničkog Instituta VTI u Beogradu i Inovacionoj laboratoriji za seizmičko inženjerstvo Sitem DC 90 u Beogradu. Eksperimentalna istraživanja u polju maksimalnih amplituda dilatacija u opsegu od 0.5% do 5%, upoređena su sa sračunatim parametrima materijala ��, �, Manson-Coffin zakona �� � �∆� �� ⁄ ��. Numerička simulacija ove zavisnosti pokazuje vrlo dobro poklapanje sa eksperimentalnim podacima sa odstupanjima u granicama od 0.9% do 1.9%. Radne hipoteze Sve hipoteze bazirane su na pretpostavkama mehanike loma i propagacije prslina u postelastičnom niskocikličnom aksijalnom naprezanju, hipoteze o strukturi materijala, prirodi veze atoma rešetke materijala kao i uticaja legirajućih hemijskih elemenata, kao i same konstrukcije apsorbera, tehnologije izrade i tolerancija u geometriji i površinskoj obradi, kao i tehnologiji izrade konstrukcije apsorbera-dampera. v. Rezultati istraživanja Može se razumeti da dobijeni rezultati ispitivanja i numeričke analize bolje objašnjavaju fenomen ponašanja rada konstrukcija u polju malog broja ciklusa jer uvode elemente akumulirane dilatacije i broja ciklusa. Razjašnjen je fenomen ojačanja i omekšavanja i definisani su dijagrami zavisnosti granice elastičnosti i drugih parametara histerezisnog ponašanja u polju malog broja ciklusa u zavisnosti od prosečne maksimalne amplitude dilatacije (0.5% do 5%) i broja ciklusa naprezanja (20 do 1000). Potpuno je jasno da samo dovoljan broj eksperimenata može dati odgovor na pitanje ponašanja konstrukcije u polju malog broja ciklusa (LCF). Obavljeno je testiranje 36 modela sa preko 50 programa testiranja. Postojeće teorije plastičnosti, posebno sa aspekta spoznaje zakona ojačanja mogu se osloniti na rezultate istraživanja (zavisnosti ��, ∆���, �, �) i na dobijene eksperimentalne dijagrame. Za potrebe definisanja histerezisnog ponašanja dobijeni dijagrami definišu fenomen ojačanja, omekšavanja i promena nagiba uzlazne i krive ojačanja. Posebno je značajna osobenost histerezisnog ponašanja u polju malog broja ciklusa, gde broj ciklusa �� i ukupno akumulirana plastična dilatacija (∆����, determinišu osnovne parametre histerezisnog dijagrama, kao što je promena granice elastičnosti (�) i promena nagiba krive ojačanja i omekšavanja (�). g. Zaključci Literatura o zamoru materijala na ciklična naprezanja je brojna. Ali, relativno mali broj istraživača se bavi zamorom materijala pod vrlo malim brojem ciklusa naprezanja, kao što je slučaj u zemljotresnim uslovima. Još je manji broj istraživanja, uređaja i opreme koji kontrolišu niskocilični zamor, kao što su histerezisni metalni damperi-zemljotresni amortizeri. U tom pravcu je zaštićen patentima jedan broj novih uređaja čije se konstruisanje oslanja ili je potvrđeno ovim istraživanjima. To su patenti zaštićeni u SAD, Australiji i Srbiji (Patent in USA No.10/555,131 from 31.10.2005, patent in Australia No. AU 2003254327A1 from 2004.11.23., P 2010/0227, P 2010/0228, P 2010/0229). Dobijeni rezultati mogu biti od koristi za uvođenje novih parametara u definisanju plastičnog ponašanja u polju malog broja ciklusa (LCF), posebno kod kompleksnih programskih sistema kao što je ANSYS i drugi. Potrebno je izvršiti veliki broj eksperimentalnih istraživanja (za raznovrsne materijale) i sačiniti grafičke i numeričke podloge (zavisnosti ��, ∆�, �, �) koje realno definišu histerezisno ponašanje. Na osnovu dosadašnjih istraživanja utvrđeni su parametri koji definišu niskociklični zamor uređaja DC 90 koji su definisani krivama (��, ∆���) a u zavisnosti od konstrukcijskog oblikovanja uređaja. Parametri kojima se definiše ponašanje dampera na zamor u domenu velikih plastičnih deformacija pri cikličnom naprezanju sa kontrolom deformacije (plastičnosti) su: Prečnik Ø (odnosno procenat redukcije osnovnog poprečnog preseka, iskustveno i eksperimentalno to je minimum 20% redukcije površine poprečnog preseka), Dužina dela sa redukovanim poprečnim presekom “pasja kost״ (odgovara maksimalno dopuštenoj dilataciji od 5% do 10%, što je iskustveno i eksperimentalno određeno i potvrđeno za određene vrste konstrukcijskog čelika-materijala koji se koriste za te potrebe), Površinska obrada elementa “pasja kost״, Elementi za obezbeđenje lokalne i globalne stabilnosti i klizanja, posebno za fazu pritiska (betonsko jezgro, aluminijumski limovi, olovni prstenovi), � i �–konstante materijala i konstrukcije dampera i Brzina promena deformacija. Od značaja je performansa da običan uzorak od konstrukcijskog čelika S235 opterećen ciklično na zamor sa maksimalnom poluamplitudom dilatacije od 5% izdrži 12 ciklusa, a damper tipa Canada HQ Royal izdrži 200 ciklusa, takođe opterećen na isti način (Patent in USA No.10/555).

Goal of this research, based on theory of fracture mechanics at low-cycle fatigue, physical-chemical structure of the steel material from which the structure of damper-absorber is made, as well as on numerous results of investigation and testing of models and structures, is to understand behaviour and discover the relationships important for definition of the mathematical model for practical use as well as for further innovation of the devices for control of hysteretic behaviour. In addition, it is necessary to find the realistic dependency of the accumulated strain in function of number of the cycles of a Damper DC 90 and other elements of the structure, because the existing relationships and knowledge in the area of low number of cycles are not covered enough. Material behaviour in plastic range is defined by three characteristics: yielding condition, flow rule and hardening rule of the material. The main goal of this dissertation is to determine the influence of number of the cycles, accumulated strains as well as the low- cycling fatigue to design of the damper of the DC 90 system. First of all, this dependency could be defined by experimental testing, based on which, a numerical model could be formulated or the theoretical bases could be modified. In case of an earthquake action, the damper DC-90 is subjected to low-cycling fatigue of material. The stress exceeds the yielding level, the material can sustain small number of cycles and it is very important to define the number of cycles which leads to final collapse of the damper. Besides that, it is necessary to define the model for design of desirable hysteretic diagram of the damper- absorber of System DC 90 seismic energy under low-cycle uniaxial strain. b. Scientific method of research Basic method of research is analytical one, based on principals of fractural mechanics. A considerable number of experiments have been done in laboratory as well as in the field conditions. Statistical methods for processing of experimental data as well as numerical calculation methods were applied. Experimental testing of plain samples of steel S235, in field of low cycles’ number (LCF), as well as dynamic testing of dampers, type Canada HQl, Canada HQ Royal, Mionica and others, has been done at the laboratories of Civil Engineering Faculty in Ljubljana, at the laboratory of Military-Technical Institute VTI in Belgrade and at the Innovation Laboratory for Seismic Engineering System DC 90 in Belgrade. Experimental testing in the field of maximum strain amplitudes in the range of 0.5% to 5%, was compared with the calculated parameters C1, γ, of Manson-Coffin law:�� � �∆� �� ⁄ ��. Numerical simulation of this relationship shows very good correlation with the experimental data with the deviation of 0.9% tо 1.9%. The working hypotheses include the basic hypotheses of fractural mechanics and cracks propagation in the post-elastic low-cycle axial stress, hypotheses on material structure, nature of atoms connection of material grid, as well as influence of alloying chemical elements and the absorber structure itself, production technology and geometry and surface processing tolerance, as well as hypotheses of technology of damper-absorber structure production. c. Research results It can be understood that gained results of research and numerical analysis better explain the phenomenon of structure behaviour in field of low number of cycles because they introduce the elements of accumulated strain and number of cycles. The phenomenon of hardening and softening was explained and diagrams of relationship between elasticity limits and other parameters of hysteretic behaviour in the range of low number of cycles, depending on average maximum strain amplitude, (0.5% tо 5%) and number of strain cycles (20 tо 1000), were defined. It is completely clear that only sufficient number of experiments can give an answer to the question about structural behaviour in field of low number of cycles (LCF). Testing of 36 models with over 50 testing programs was conducted. The existing plasticity theories, especially from the aspect of hardening low, are based on research results (dependence ��, ∆�, �, �) and the gained experimental diagrams. For the needs of defining the hysteretic behaviour, the gained diagrams define the phenomenon of hardening, softening and change of the slope of the hardening curve (�, ��), by which new parameters in hysteretic response of the structure are introduced. d. Conclusions Literature related to cyclic strain fatigue is numerous one. But relatively little number of researchers study the fatigue of material under very low number of strain cycles, as in the case of an earthquake excitation. Even more, very few information about devices and equipment which control the low-cycle fatigue, like metal hysteretic dampers - earthquake absorbers exist. In that direction, several new devices related to above research have been patent-registered by the author of this theses. These are the patents protected in USA, Australia and Serbia (Patent in USA No.10/555,131 from 31.10.2005, patent in Australia No. AU 2003254327A1 from 2004.11.23., П 2010/0227, П 2010/0228, П 2010/0229). The gained results can be used for introduction of new parameters defining plastic behaviour in field of low cycle number (LCF), especially at complex software like ANSYS and others. It is necessary to perform a large number of experimental researches (for different materials) and to make graphical and numerical bases (dependences: ��, ∆�, �, �), which realistically define the hysteretic behaviour. Based on previous research, the parameters defining low-cycle fatigue of DC90 device were defined by curves (Nf, ∆���), and in dependence of structural shaping of the devices. The parameters which define the fatigue behaviour of dampers in high-plastic cycling range with deformation control (of plasticity) are: Radius Ø (of percent reduction of basic cross section, experimentally is minimum 20% ). Length of reduced dog-bone cross-section(corresponds to the maximum allowed strain from 5% to 10%, which is experimentally proved and confirmed for certain kinds of structural steel – the material used for that purpose) Surface processing of ’’dog-bone’’ element. Elements for ensuring local and global stability and sliding, especially for pressure phase (concrete core, sheet-aluminium, lead rings) C and γ –constants of dampers material and structure Strain rate (velocity of strain changing in time) The capability of ordinary sample made of structural steel S235, subjected to cycling fatigue with maximum semi-amplitude of strain of 5%, to hold 12 cycles, as well as the capability of the damper type Canada HQ Royal to hold 200 cycles loaded on the same way (Patent in USA No.10/555) is of particular importance.

Starost kao demografska odrednica potrošnje domaćinstava u Srbiji

Age as demographic determinant of household consumption in Serbia

Predmet istraživanja jeste potrošnja domaćinstava na čiji nivo i strukturu, između ostalog, utiču starost nosioca domaćinstva i demografske karakteristike članova domaćinstva. Opšte prihvaćen način uvođenja starosti u razmatranje potrošnje domaćinstava jeste preko starosti nosioca domaćinstva, koji se inače koristi u ekonometrijskim istraživanjima potrošnje stanovništva. Sa druge strane, cilj ovog istraživanja je da na primeru domaćinstava u Srbiji utvrdi uticaj starosti kao demografske odrednice na strukturu lične potrošnje, kao i da objasni smer i intenzitet uticaja posmatranih demografskih karakteristika domaćinstava. Promene u demografskim strukturama neminovno vode i do promena u strukturi lične potrošnje. Otuda bi objašnjenje uticaja starosne strukture na strukturu lične potrošnje vodilo potpunijem razumevanju promena u obimu i strukturi lične potrošnje...

The main objective of this research is identification and explanation of changes in the structure of private consumption as a function of the age of an individual. However, it is not possible to isolate and measure the consumption of individual which is being realized within the household. Yet, it is possible to make a compromise and instead of an individual, as an observation unit to take the household. The reason why in this type of research individual can not be the subject of research, lies in the definition of the household. Generally accepted way of introducing age into household consumption research is through the age of the household head, which is used in econometric studies of household consumption. On the other hand, the aim of this study is to, in the case of households in Serbia, determine the influence of age as the demographic characteristics of the structure of private consumption, as well as to explain the direction and intensity of the impact of the observed demographic characteristics of households. Changes in the demographic structure will inevitably lead to changes in the structure of private consumption. Hence, the explanation of the impact of the population age structure on the structure of private consumption would led to a more complete understanding of changes in the scope and structure of household consumption...

Inovativni modeli upravljanja zaštićenim prirodnim dobrima kao podrška uspostavljanju i funkcionisanju ekološke mreže Srbije

Innovative protected areas management models in support of the establishment and operation of the ecological network of Serbia

Uspostavljanje zaštićenih područja predstavlja jedan od najefikasnijih načina zaštite predela u kojima je priroda ostala sačuvana, pa samim tim ova područja čine jedan od najvažnijih prirodnih resursa jedne zemlje. Dobro upravljanje podrazumeva postojanje jasnih i preciznih upravljačkih ciljeva, a realizuje se preko planova upravljanja, koji predstavljaju propise kojima se jasno planiraju mere i aktivnosti zaštite nekog područja, kao i razvojne smernice, uz uvažavanje potreba lokalnog stanovništva koje na tom prostoru živi ili koristi njegove resurse. Efikasno upravljanje zaštićenim područjima je od ključne važnosti, da bi svrha njihovog uspostavljanja bila opravdana, a postavljeni ciljevi ostvareni. Cilj ovog rada je analiza stanja zaštite prirode u Srbiji u oblasti zaštićenih područja, ukazivanje na nedostatke i probleme, preporuke i moguća rešenja, kako bi se kapaciteti upravljača povećali, a upravljanje postalo efikasnije. Radi upoznavanja sa konkretnom situacijom i stavovima samih upravljača pripremljena je anketa, odnosno upitnik, a radi ispitivanja institucionalnog okruženja urađen je ekspertski intervju, koji je omogućio sagledavanje međusobnih odnosa i budućih planova. Odabrana pitanja bila su otvorenog, zatvorenog i mešovitog tipa, a anketiranje upravljača i intervju su realizovani u periodu od decembra 2014. do marta 2015. Upitnike je dostavilo 50 upravljača, koji upravljaju na 100 zaštićenih područja, a na osnovu njihovih odgovora analizirani su kapaciteti upravljača, vii njihov odnos sa lokalnom zajednicom, turizam u zaštićenim područjima, realizacija projekata, postojanje baza podataka i vršenje monitoringa, faktori ugrožavanja dobra, kao i mere zaštite koje se u odnosu na njih preduzimaju. Ekspertski intervju je urađen sa dva predstavnika Ministarstva poljoprivrede i zaštite životne sredine. Radom je obuhvaćen nacionalni i IUCN međunarodni sistem kategorizacije upravljanja zaštićenim područjima, savremeni modeli upravljanja zaštićenim područjima, Natura 2000 mreža zaštićenih područja unutar granica Evropske unije, Zaštita prirode u Srbiji – strateški, pravni i institucionalni okvir. Na kraju, kada sagledamo kompletnu situaciju u ovoj oblasti, možemo konstatovati da je najveći izazov za zaštićena područja u Srbiji, ali i uopšte, da se razvije sistem održivog upravljanja koji podržava zaštitu prirode i omogućava dugoročnu korist za lokalno stanovništvo.

The establishment of protected areas is one of the most effective ways to protect the areas with preserved nature, which are, as such, among the most important natural resources of a country. Proper management implies clear and precise management objectives, implemented through management plans, that is, clear procedures for planning measures and activities to protect certain area, as well as development guidelines, while observing the needs of the local population living in the area or using its resources. Effective management of protected areas is essential in justifying the purpose of their establishment and meeting their objectives. The aim of this paper is to assess the state of nature conservation in Serbia in the field of protected areas, to point out the shortcomings and problems, as well as recommendations and possible solutions, in order to increase the management efficiency and capabilities. In order to assess the actual situation and positions of the managers themselves, a questionnaire - survey was developed, and an expert interview was conducted in order to examine the institutional environment, which enabled consideration of the mutual relations and future plans. Selected questions were of open, closed and mixed types; the survey and the interview were conducted in the period from December 2014 to March 2015. The questionnaires were submitted by 50 managers operating in 100 protected areas. On the basis of their responses, the capabilities of the managers were analyzed, as well as their relationship with the local community, tourism in protected areas, ix implementation of projects, existence of databases and monitoring, factors threatening the environment, and appropriate protection measures. The expert interview was conducted with two representatives of the Ministry of Agriculture and Environmental Protection. This paper covers the national and international IUCN categorization systems of protected areas management, contemporary protected area management models, Natura 2000 network of protected areas within the European Union, as well as the environmental protection in Serbia - strategic, legal and institutional framework. Finally, considering the overall situation in this area, we can conclude that the greatest challenge regarding the protected areas in Serbia, but also in general, is to develop a sustainable management system supporting the environmental protection and providing long-term benefits for the local population.

Atmosferska cirkulacija kao faktor prostorne raspodele temperatura vazduha i padavina u Srbiji

Atmospheric circulation as a factor of spatial distribution of air temperaure and precipitation in Serbia.

U radu je analiziran uticaj cirkulacije atmosfere na temperature vazduha i padavine na prostoru Srbije. Cirkulacija atmosfere je veoma složen kompleks fizičkih mehanizama kojima se obavlja razmena vazdušnih masa na Zemlji i kao takva predstavlja značajan faktor raspodele vrednosti klimatskih elemenata na određenom prostoru. Tipologije cirkulacije atmosfere omogućavaju sagledavanje njenih osobina i analizu uticaja na vreme i klimu. Poznavanje odlika učestalosti i postojanosti cirkulacionih tipova je veoma važno u studijama klimatske varijabilnosti. Postoji veliki broj različitih tipologija i zadatak ovog istraživanja je odabir najpogodnijih za analizu temperaturnih i padavinskih uslova u Srbiji. Standardizacija različitih tipologija sa istim klasifikovanim podacima, na istom prostoru i sa istim brojem tipova omogućava uporedivost različitih kataloga cirkulacionih tipova čime je olakšan njihov odabir u daljem istraživanju. U ovom radu katalozi cirkulacionih tipova su izvedeni primenom klasifikacionog softvera Sost733class-1.2 i deo su baze kataloga Cost733cat v2.0. Klasifikovane su dnevne vrednosti vazdušnog pritiska na nivou mora (MSLP) posebno i zajedno sa visinom geopotencijalnog polja od 500 hPa (Z500) za Severno-atlantsko-evropski sektor (domen Evropa) i za prostor Jugoistočne Evrope sa Balkanskim poluostrvom u središtu (domen JI Evropa), pri čemu je broj tipova 9, 18 i 27. Izvor podataka za vazdušni pritisak je ERA-40 Re-analysis, dok su za prostor Srbije korišćeni podaci sa 30 stanica za dnevne vrednosti temperatura vazduha i padavina. Analiziran je period 1961-2000. godina. Odabir kataloga čiji tipovi najbolje stratifikuju dnevne temperaturne i padavinske događaje na prostoru Srbije je izvršen primenom statističkih indeksa kako bi se izdvojili oni kod kojih je varijansa događaja unutar tipova najmanja moguća, dok je između tipova najveća moguća. Najbolji rezultati su dobijeni za tipologije kod kojih su tipovi proizvod primene metode analiza glavnih komponenti, pri čemu je klasifikacija obavljena primenom nehijerarhijske k-means klaster metode. Prednost imaju katalozi kod kojih su tipovi nastali klasifikovanjem MSLP i Z500 u odnosu na to kada se klasifikuje samo MSLP. I domen Evropa i domen JI Evropa pružaju dovoljno informacija za analizu prostorno-vremenske varijabilnosti temperatura vazduha i padavina u Srbiji. U pogledu broja tipova najoptimalniji rezultati se dobijaju za kataloge sa 18 tipova. Prepoznati su cirkulacioni uslovi koji su u vezi sa dnevnim vrednostima temperatura vazduha i padavina iznad ili ispod proseka, odnosno „umerenimˮ uslovima. Takođe, izdvojeni su tipovi sa najvećom efektivnošću za ekstremne događaje. Prostorna raspodela temperatura vazduha i padavina u Srbiji je analizirana primenom geostatističke metode interpolacije ̶ regresioni kriging. Problematika klimatske „spacijalizacijeˮ sa cirkulacijom atmosfere kao glavnom eksplanatornom varijablom značajno doprinosi u analizi prostorne raspodele klimatskih elemenata, o čemu svedoče i rezultati ove studije. Pored cirkulacije atmosfere, razmatran je i uticaj geografske širine i dužine, nadmorske visine, kao i udaljenost od izvora vlage u slučaju padavina. Za temperature vazduha, u najvećem broju cirkulacionih tipova, nadmorska visina ima dominantan uticaj na prostornu raspodelu, dok u slučaju padavina, prostorna raspodela je u velikoj meri određena pravcem iz koga dolaze vazdušne mase, odnosno udaljenošću od izvora vlage. Pored prostorne, razmatrana je i vremenska komponenta varijabilnosti ̶ trend posmatranih varijabli. Utvrđeno je da se promene u temperaturama vazduha i padavinama na prostoru Srbije mogu dovesti u vezu sa promenama u učestalosti i postojanosti cirkulacionih tipova. Značajnost trenda vremenskih serija je testirana primenom Man-Kendal testa sa Senovom ocenom nagiba linearnog trenda. Na osnovu svih dobijenih rezultata zaključuje se da: a) cirkulacija atmosfere je značajan faktor prostorno-vremenske varijabilnosti temperatura vazduha i padavina na teritoriji Srbije, b) u Srbiji postoji regionalni aspekt klimatskih promena uslovljen odlikama cirkulacije atmosfere i v) primena kataloga cirkulacionih tipova omogućava proširenje saznanja o prostorno- vremenskoj dimenziji kolebanja klime na određenom prostoru.

This study explores the impact of atmospheric circulation on air temperatures and precipitation on the territory of Serbia. Atmospheric circulation represents the complex of physical mechanisms by which exchange of air masses on the Earth is done and it is a factor of spatial distributions of climate parameters in certain area. Typologies of atmospheric circulation patterns are very useful tools in climate studies for analysis the features of atmospheric circulation and for evaluation of its impact on weather and climate. The study of the changes in frequency and persistency of circulation types is very important for understanding of climate variability. There is a large number of typologies and the aim of this research is to select the most suitable for the analysis of temperatures and precipitation conditions in Serbia. In order to choose the best typology it is necessary to standardize various classification methods with the same classified data, for the same spatial domains, and with uniform number of types. In this study, catalogues of circulation types are produced using the classification software Сost733class-1.2 and they are contained in Cost733cat v2.0 database of catalogues. Daily values of mean see level pressure (MSLP) are classified separately and together with 500 hPa geopotential high (Z500) for North-Atlantic-European region (domain Europe) and for Southeastern Europe with Balkan Peninsula in central part (domain SE Europe). The number of types is 9, 18, and 27 and the source for air pressure data is ERA-40 Re-analysis. Daily air temperatures and precipitation from 30 stations in Serbia are used. The research period is 1961-2000. Selection of catalogs of circulation types which have the best ability to stratify daily temperature and precipitation events on the territory of Serbia was carried out using the statistical indices in order to select those with lowest values of variance within types, while the highest possible between types. The best scores have typologies in which types are produced by Principal Component Analysis and classification is done by non-hierarchical k-means cluster analysis. Better results are when the types are based on MSLP and Z500 data compared to MSLP data only. Both classified spatial domains (Europe and SE Europe) provide enough information for exploring spatio-temporal variability of temperature and precipitation in Serbia. The catalogs with 18 types show better results compared to those with 9 and 27 types. Circulation types which represent synoptic conditions related to moderate, under or over average temperature and precipitation conditions are recognized. Also, types with high efficiency for extreme events are isolated. Spatial distribution of air temperatures and precipitation in Serbia is analyzed using geostatistical interpolation method ̶ Regression Kriging. It is shown that climate ˮspatialisationˮ with atmospheric circulation as a leading predictor improves the understanding of spatial variability of climate paremeters. Beside the atmospheric circulation, a few additional predictors are explored: latitude and longitude, altitude and distance from the water sources, especially for precipitations. According to results, in case of many circulation types, the most dominant factor in spatial distribution of air temperatures is altitude, and the trajectories of air masses and distances from water sources are the most significant in spatial distribution of precipitation in Serbia. The variability of time series (trend) was also subject of this study. The results show that changes in temperatures and precipitation are related to changes in frequencies and persistency of circulation types. The Mann-Kendal test is used to determine significance of trend and Sen's estimator for linear slope rate. According to the all obtained results in this research, it could be concluded: a) atmospheric circulation is significant factor of spatio-temporal variability of air temperatures and precipitation on the territory of Serbia, b) there is regional aspect of climate change on the territory of Serbia under the influence of atmospheric circulation, and c) application of catalogs of circulation types extends the knowledge about spatio- temporal dimensions of climate fluctuations in a particular area.

Transformacija banja Srbije u savremene centre spa i wellness turizma

Transformation of spas in Serbia into modern centers of spa and wellness tourism

Imajući u vidu visoke stope rasta spa i wellness turizma na globalnom nivou, kvantitet i kvalitet konkurentskih ponuda beleži kontinuirani rast, te je u takvim uslovima vrlo zahtevan zadatak izboriti se za adekvatnu poziciju na tržištu. Budući da se Srbija, uprkos izuzetno povoljnim prirodnim resursima za razvoj banjskog turizma, još uvek ubraja u nedovoljno razvijene destinacije, od posebnog značaja za buduće unapređenje ovog vida turizma i pozicioniranje banja kao turističkih destinacija na međunarodnom turističkom tržištu, jeste upravo njihova transformacija od tradicionalnih lečilišta u moderne centre spa i wellness turizma. Osnovni cilj istraživanja u okviru ove disertacije je postavljanje naučno relevantnih osnova tumačenja procesa transformacije tradicionalnih banja Srbije u savremene centre spa i wellness turizma, koje će biti aplikativno prihvatljive i potkrepljene adekvatnim teorijskim okvirom. Zadaci istraživanja odnosili su se na razradu problematike turizma u banjama Srbije, s jedne strane analizom motivacije turista koji posećuju banje, a sa druge analizom atributa atraktivnosti banja. U disertaciji se pokušao razviti model koji bi obuhvatio sve faktore koji utiču na proces donošenja odluke turista kada je reč o izboru banje kao mesta za odmor. Dosadašnje studije ili su obuhvatale samo motivaciju (push i pull motive) ili samo ograničenja, dok je u ovoj studiji predstavljen integralan model koji uključuje sva tri faktora. Razumevanje i prilagođavanje motivaciji i ponašanju turista je jedini način da banje budu konkurentne na turističkom tržištu. Anketno istraživanje sprovedeno je na uzorcima turista u više banja u Srbiji. Analiza svih faktora koji utiču na proces donošenja odluke o izboru banja kao turističkih destinacija u Srbiji urađena je uz pomoć analitičko - hijerarhijskog procesa (AHP metod). Kao rezultat toga izdvojili su se vodeći ii faktori na lestvici hijerarhije, kao i oni najmanje bitni kod turista koji posećuju banje. Istraživanje atraktivnosti banja u Srbiji, sprovedeno među ekspertima iz ove oblasti, imalo je za cilj određivanje značaja predloženih faktora (atributa), a zatim i rangiranje analiziranih banja prema atraktivnosti wellness ponude. Eksperti su ocenjivali dvadeset banja u Srbiji i analiziranjem dobijenih podataka AHP metodom, kao najatraktivnije izdvojile su se Vrnjačka Banja, Vrdnik u Bukovička banja. Kako bi zadovoljile zahteve savremenih turista, banje u Srbiji treba da ponude integralni turistički proizvod koji obuhvata: raznovrsnu ponudu zdravstvenih tretmana zasnovanu na prirodnim resursima, medicinski program, wellness program, kozmetičke tretmane, sportske aktivnosti, u kombinaciji sa kvalitetnim smeštajnim kapacitetima, autentičnom gastronomskom ponudom i kulturno-zabavnim sadržajem.

Bearing in mind the high growth rates of spa and wellness tourism on a global level, the quantity and quality of competitive bidding has continuous growth, and in these conditions it is extremely difficult for everyone to get adequate market position. Since Serbia, despite the extremely favorable natural resources for the development of spa tourism, is still among the underdeveloped destinations, of particular importance for the future improvement of this type of tourism and positioning of spas as a tourist destination on the international tourist market is the transformation of the traditional spas in modern spa centers and wellness tourism. The main aim of the research part of this thesis is to set up a relevant scientific basis for interpretation of the transformation process of traditional spas Serbia into modern centers spa and wellness tourism; this basis must be applicable, relevant and supported by adequate theoretical framework. The task of this research was to identify the problems of development of tourism in Serbian spas, on the one hand through the analysis of the motivation of tourists who visit spas, and on the other by analyzing attributes of attractiveness spas. This thesis aims to develop a model that would encompass all the factors that influence the decision-making process of tourists when it comes to choosing the spa as a place to rest. Previous studies either included only motivation (push and pull motives) or constraints, while this study presents an integrated model that includes all three factors. Understanding and adapting to the motivation and behavior of tourists is the only way to be competitive at the spa tourism market. The survey was conducted on samples of several tourists in spas in Serbia. Analysis of all the factors that influence the decision-making process on the selection of spas as tourist destinations in Serbia was carried out with the help of Analytical - Hierarchy Process (AHP method). As the result, the leading factors on a scale of hierarchy were identified, as well as the factors least important to the tourists who visit spas. iv Research of attractiveness of spas in Serbia, conducted among experts in this field, was aimed at determining the nature of the proposed factors (attributes), and then at analyzing and ranking the spas according to the attractiveness of wellness spas offers. The experts evaluated the twenty spas in Serbia and by analyzing the data obtained AHP method as the most attractive they proclaimed the following spas: Vrnjačka Banja, Bukovička Banja, and Vrdnik. In order to meet the demands of modern tourists, spas in Serbia should offer an integrated tourism product that includes: a diverse selection of medical treatments based on natural resources, medical program, wellness program, cosmetic treatments, sporting activities, combined with quality accommodation, authentic cuisine cultural and entertainment content.

Tranzicija feriliteta i kontrola rađanja stanovništva Timočke krajine

Transition of fertility and birth control population of the Timocka krajina

Demografska tranzicija uslovljena nedovoljnim rađanjem karakteriše savremene negativne demografske procese koji su započeti u zemljama Evrope, a tokom druge polovine 20.veka postaju odlika razvijenih zemalja i zemalja u razvoju usvajanjem niskih reproduktivnih normi. Ovaj period odlikuje Druga demografska tranzicija sa promenama u sistemu vrednosti, porodičnim odnosima i fertilitetnim odlikama stanovništva, kao i sa usvajanjem metoda kontrole rađanja. Prostor Timočke krajine se odlikuje demografskom tranzicijom plodnosti ženskog stanovništva već krajem 19.veka, uslovljavajući negativni trend demografskog razvoja koji predstavlja preteču ekstremno niskog fertiliteta Srbije. Ovi procesi su determinisani istorijskim procesima na ovom prostoru, kultrološkim, etničkim, istorijskim nasleđem i ukorenjenim oblicima reproduktivnog ponašanja stanovništva, tako da je pored društvenog, privrednog i ekonomskog razvoja, značajna i specifičnost demografskog razvitka prostora. Transformacija proširene u prostu reprodukciju, i dostizanje nivoa fertiliteta ženskog stanovništva nedovoljnog za prostu zamenu generacija determiniše na samom početku 21.veka, da se ovaj prostor Srije, nalazi u odmakloj fazi demografske tranzicije sa dubokom biološkom depopulacijom. Dostignuti nivo tranzicije fertiliteta i tranzicije kontrole rađanja na prostoru Timočke krajine praćen je i intenzivnim prostornim kretanjima kroz istorijske etape, naglašavajući gubitak populacione snage kojim se odlikuje ovaj prostor više od jednog veka, kao i drugim odlikama stanovništva i društva određenih istorijskih etapa. Zato je značajno i naučno opravdano sagledati ove fenomene i kroz dostupne izvore naučne i stručne literature sa podacima o ovom prostoru. Cilj u ovoj doktorskoj disertaciji je utvrditi i naučno argumentovati osnovne karakteristike i specifičnosti demografskog razvitka, tranzicije fertiliteta i 5 tranzicije kontrole rađanja Timočke krajine...

The demographic transition caused by insufficient birth rate is characteristic for modern negative demographic processes which started in European countries, and during the second half of the 20th century became a distinctive feature of developed and developing countries by accepting low reproductive norms. This period is marked as Second demographic transition with changes in value system, family relations and fertility features of the population, as well as accepting the methods of birth control. The Timocka krajina region started having a demographic transition of the fertility of female population at the end of the 19th century, which caused a negative trend of demographic development leading to an extremely low fertility rate in Serbia. These processes are determined by historical events in this region and by cultural, ethnical and historical legacy and forms of reproductive behavior of the population, so that beside social, industrial and economical factors, another important factor is the specific demographic development of the region. The transformation from expanded to simple reproduction rate and reaching the fertility level of female population which is inadequate for the plain replacement of generations determines that this region of Serbia is in the late phase of a demographic transition towards deep biological depopulation. The reached level of fertility transition and birth control transition in Timocka krajina region is accompanied by intensive migration through historical times, which marks the loss of work force which was characteristic for this area for more than a century like other features of the population and societies at different historical times. Thus it is important and scientifically justified to observe these phenomena through available sources of scientific and technical publications about this region. The aim of this dissertation is determining and scientifically argumenting the basic characteristics and specificity of demographic development of fertility transition and transition of birth control in Timocka krajina region. The task of this research is a scientific exploration of the influence of traditional and historical legacy and modern demographic development, migrational components and non-demographic influence on the establishment and formation of demographic flows and levels of transition of fertility and birth control, temporal and spatial characterisation of demographic processes and the consequences of 8 biological depopulation, with establishing phases, stages and the consequences of demographic aging, disturbing of relations of age contigents of female population, as well a scientific analysis of mutual dependency of the development of population and the area it inhabits...

Institut odobrenja plana u Srbiji

Legal institute of spatial and urban plans endorsement in Serbia

Rezime: Tema doktorske disertacije "Institut odobrenja plana u Srbiji: primena i perspektiva razvoja" do sada nije bila predmet kompleksnijih istraživačkih interesovanja prostornih i urbanih planera profesionalno posvećenih izučavanju srpskog planiranja i zakonodavstva. Tome ne protivureči činjenica da je radova na bliske teme bilo i da su ih sporadično ispisivali pravnici, politikolozi, istoričari, arhitekte, kulturolozi, sa svog, osobenog i tematski i usmerenog aspekta. Ipak, zapaženijih istraživanja okvira i komponenti ove regule, njenih korena, mesta, uloge i značaja u razvoju srpskog prostora i naselja nije bilo. Sto trideset godina dugo prisustvo instituta odobrenja plana u srpskom zakonodavstvu i praksi otvara širok tematski krug pitanja vezanih za njegovu pojavu, pravce razvoja/evolutivnost, sadržaj, ulogu, značaj, potencijal i sl., vrednih pažnje. Istraživanje na osoben način dotiče i proučavanje specifičnih odnosa u politici i društvu koji su omogućili prihvatanje/uvođenje i razvoj ovog instituta i njegovo, još uvek, aktivno prisustvo. Stojanović kaže da autor bira svoju temu na osnovu na razne načine formiranih afiniteta i interesovanja, ali i emocija, i da izborom svog predmeta istraživanja on pokušava sebi da objasni fenomene koji njega lično intrigiraju, opsedaju, koji ga teraju na neprekidno preispitivanje (Stojanović, D., 2012), što u ovom slučaju sasvim odgovara istini. No, razlozi i podsticaji za ovaj rad sadržani su i u činjenicama koje se javno iznose, a vezane su za stanje u prostoru Srbije, institucionalne slabosti i profesionalne propuste. Sve pomenuto navodi na razmišljanje, preispitivanje i otvara prostor za traženje novih, boljih i efikasnijih modela i rešenja. Disertacija, suštinski, ima dva velika dela – prvi obuhvata globalni, nacionalni i lokalni ambijent upravljanja prostornim razvojem, kao i njihov međuodnos (koegzistenciju), dok drugi čini analiza institucionalnog okvira i prakse instituta odobrenja plana/saglasnosti na plan. U okviru prvog dela analiziran je smisao i značaj planiranja prostornog/urbanog razvoja u savremenom globalizovanom svetu, u velikim integracijama i savremenim nacionalnim državama, sa posebnim osvrtom na lokalne vlasti, odnosno na hijerarhijski niže nivoe vlasti. Drugi deo se bavi analizom instituta odobrenja plana u Srbiji, uz osvrt na važnije reformske sadržaje koji moraju da budu sprovodeni, kako bi državne i lokalne vlasti imale potreban kapacitet da koriste ovaj institut u upravljanju prostornim razvojem. Odobrenje plana, kao međuodnos države i lokalne samouprave u materiji planiranja prostornog razvoja je prevashodno proces. Ta njegova suštinska, a često zanemarivana karakteristika predstavlja element koji ga razlikuje od drugih pravnih instituta od kojih je ovaj međuodnos sačinjen. Zato, može se reći da je odobrenje plana razvoj određenih pravnih instituta posmatranih u nekom vremenskom periodu, odnosno trenutna slika trajnije promenljivog stanja u materiji planiranja prostornog razvoja. U skladu sa tim, u fokus istraživanja je stavljen proces, odnosno kinetička, dinamička strana ovog instituta, ali bez zanemarivanja njegovih statičkih karakteristika - te karakteristike nisu vezane samo za državu kao instituciju, planski sistem, planski proces kao formalnost i dr, već za prostor kao javno dobro i kao javni interes, za demokratiju, prava, moral i dr, kao opšte vrednosti. U dinamičkom smislu, ovaj institut je sagledan i kao vrsta upravne reforme, kako bi se dao odgovor na pitanje o njegovoj mogućoj anahronosti u aktuelnom urbanističkom zakonodavstvu. U radu su obrađeni osnovni pojmovi u vezi sa odobrenjem plana i sumirana su (domaća i uporedna) iskustva o ovom institutu, a posebno iskustva njegove primene u Srbiji u različitim periodima razvoja. Sagledan je i analiziran i širi pravni i institucionalni okvir prostornog i urbanističkog planiranja u nas. Osnovne hipoteze, postavljene u prijavi rada, na osnovu docnijih teorijskih i empirijskih uvida unekoliko su korigovane i dopunjene, a rezultati njihove provere izloženi su u radu. Neki od tih nalaza, mogu se iskoristiti kao polazišta za dalja istraživanja. Važno je, takođe, istaći, i da su u periodu nakon započinjanja rada (prijave rada), izmenjeni zakonski okviri ovog instituta što je zahtevalo i blagu promenu kursa. U Zakon o planiranju i izgradnji Republike Srbije je, posle višegodišnjeg "odsustva", ponovo uvedena komisija za kontrolu usklađenosti planskih dokumenata kao posebno telo koje formira ministar, a po prvi put je donet i poseban tehnički pravilnik o njenom radu. Važna promena je i da se posle gotovo 130 godina kontinuiteta, na urbanističke planove gradova i naselja - sedišta jedinice lokalne samouprave, više ne pribavlja "odobrenje"/"mišljenje"/"saglasnost" višeg upravnog nivoa. Zona "međe" se, dakle, pokrenula i, kako stvari stoje, jedina konstanta u budućnosti je - promena. Vrata ka promenama, zonama novih polja, odškrinuta su kroz zaključna razmatranja ovog rada. Nedovoljna vidljivost, stanje titraja, dok se slika nije umirila – tu leži snaga (trajnost) instituta odobrenja plana.

Abstract: Until present, the topic of this doctoral dissertation "Legal Institute of Spatial and Urban Plans Endorsement in Serbia: Its Application and Development Perspectives" has not been in the focus of more complex research efforts of spatial and urban planners who are professionally dedicated to studying the Serbian spatial and urban development planning and relevant legislation. This is not in contravention with the fact that research papers on similar topics have been sporadically published by lawyers, political scientists, historians, architects and culturologists who were driven by their particular and thematic approaches. Still, we have not witnessed any significant research studies related to the framework and components of this regulation, its origins, place, role and its importance for the Serbian spatial and urban development. The 130-year long history of the legal institute of spatial and urban plans endorsement in Serbian legislation and practice opens up a wide range of topical issues related to its existence, directions of development/evolutivity, contents, role, significance, potential, etc. which are worth exploring. In its own way, the present research also touches upon specific political and social relationships, which made the acceptance/incorporation and development of this legal institute and it’s, still active presence, possible. According to Stojanović, each author chooses a research topic based not only on its own affinities and interests formed in different ways, but on emotions, as well, and that with its choice of research topic the author endeavours to explain the phenomena he/she is personally intrigued by, obsessed with, and which call for permanent re- examination (Stojanović, D, 2012), which in this particular case fully corresponds to the truth. However, the reasons and a true impulse for this dissertation can also be traced back to facts in public domain regarding the territory of Serbia, institutional weaknesses and professional failures. All of the above mentioned call for reflection, re-examination and opening a new leeway in search of fresh, improved and more efficient models and solutions. In fact, the dissertation consists of two large parts – the first one covers global, national and local environments for spatial development management, and their interrelations (coexistence), while the second part presents an analysis of the institutional framework and the practice of the legal institute of spatial and urban plans endorsement/consent. The first part deals with analysis of the meaning and importance of spatial/urban development in contemporary globalized world, within huge integrations and modern national states, with a particular emphasis on local authorities and/or hierarchically lower government levels. The second part deals with analysis of the legal institute of endorsement of spatial and urban plans in Serbia, with a retrospect of major reform systems which have to be implemented so that the national and local- government authorities would build the necessary capacity to use this legal institute in spatial development management. The endorsement of plans, as a correlation between the state and local self- governments in the planning of spatial development is primarily a process. This crucial and its often neglected characteristic represents an element which distinguishes it from other legal institutes constituting this correlation. Therefore, one might say that the endorsement of the plans means development of certain legal institutes studied over a defined time period and/or the current picture of a constantly changing situation on the topic of development of spatial planning. Consequently, the focus of the present research was on the process itself i.e. the kinetic, dynamic side of this legal institute, while not disregarding its static characteristics – these characteristics are not only linked to the state, as an institution, the system of planning, the planning process as a formality, but are also linked to the environment as public good and public interest; to democracy, rights, moral, etc. as general values. In a dynamic sense of the meaning, this legal institute was studied as a type of an administrative reform, in order to offer an answer to the issue of possible anachronism within the current urban development legislation. The dissertation considers basic terms related to endorsement of spatial and urban plans and sums up (local and comparative) experiences on this legal institute, especially the experiences related to its application in Serbia over different periods of development. Wider legal and institutional frameworks of spatial and city planning in our country were also considered and analyzed. The original hypotheses, posed in the dissertation application were thereafter corrected and supplemented to some extent, due to new theoretical and empirical insights, and the results of their verification are presented in the dissertation. Some of these findings could be used as starting points for further research. It is also important to underline that, after commencement on the research work (dissertation application), the legal frameworks of this legal institute were changed, which called for a slight change of the course. After a long-time “absence”, the Commission for the Oversight of Compliance of Planning Documents, as a special body formed by the minister was re-incorporated into the Law on Planning and Construction of the Republic of Serbia and for the first time a separate technical rulebook on its work was introduced, too. An important novelty is also that, after almost uninterrupted period of 130 years, the seats of local self-government units no longer need to obtain “approval”/”opinion”/”consent” from higher administrative levels for urban development of their own cities and settlements. “The boundary” zone has been extended and, the way the things are, the only constant one may count on in the future shall be – the change itself. The door leading to the change, some new field’s zones have been put ajar in the closing arguments of the present dissertation. Insufficient visibility, a state of “vibration” before the picture finally stabilizes is exactly where the strength (durability) of the legal institute of spatial and urban plans endorsement lies.

Promene načina korišćenja zemljišta i vlasništva nad zemljištem sa aspekta prostornog planiranja

Land use changes and land ownership changes from the spatial planning aspect

Polazeći od složenosti i multidisciplinarnosti oblasti korišćenja zemljišta, predmet istraživanja u ovoj doktorskoj disertaciji ograničen je na promene načina korišćenja zemljišta i vlasništva nad zemljištem sa aspekta prostornog planiranja, a obuhvatio je i komponente zemljišne politike koje se na ova pitanja odnose (pravo držanja i korišćenja zemljišta, zemljišna administracija, pribavljanje zemljišta i dr.). Prostorno planiranje ima fundamentalne uticaje na kontrolisanje zemljišta, kao legalnog instrumenta države za ostvarivanje javnog interesa. Pri tome, ima zadatak da pronađe balans između prava vlasnika da koristi svoje zemljište i javnih interesa, te je, u ovom smislu, ključna spona između planiranja, zakonskih okvira i vlasničkih prava i interesa na zemljištu. U disertaciji se naročita pažnja daje oblicima ograničavanja prava vlasništva nad zemljištem koji proizilaze iz intervencije države u cilju sprovođenja javnog interesa. Planiranjem se uspostavljaju obaveze i ograničenja na zemljištu u pogledu načina korišćenja, te, po pravilu, podrazumeva restrikciju prava vlasništva (npr. promenama vlasničkih odnosa, obavezom sprovođenja zaštite, pravilima uređenja i sl.) ili potpuno izuzimanje kod promene načina korišćenja za javne namene, što zahteva i sprovođenje kroz evidencije o zemljištu (katastar nepokretnosti i dr.). ii Istovremeno, u disertaciji su istraživane metode i postupci novijih pristupa strateškog i integralnog planiranja, svojstveni održivom planiranju i upravljanju poljoprivrednim zemljištem. U tom pogledu, sve više je naglašena potreba za evaluacijom zemljišnih resursa u procesu planiranja korišćenja zemljišta, kao i integrisanjem novijih pristupa sprečavanja degradacije zemljišta u ovaj proces, kako bi se na adekvatan način angažovali planski instrumenti za pažljivo kontrolisanje zauzimanja poljoprivrednog zemljišta. Doktorska disertacija urađena je u formi naučne studije, a istraživanje se temelji na teorijskim saznanjima, ali i praktičnim modelima, odnosno specifičnim praksama planiranja, strategijama i pristupima, kao i širim institucionalnim i strukturnim analizama. Jedan od primarnih ciljeva disertacije jeste da obezbedi platformu osnovnog znanja o nedovoljno istraživanim uticajima planiranja načina korišćenja zemljišta na vlasništvo nad zemljištem u Srbiji, prevashodno se fokusirajući na promene koje obuhvataju poljoprivredno zemljište. Strateška i normativna regulativa o korišćenju i zaštiti poljoprivrednog zemljišta kao dobra od opšteg interesa, ukazuje na potrebu njegove prioritetne zaštite. S obzirom na primarni zadatak istraživanja, promene u načinu korišćenja zemljišta nisu kvantitativno izražavane, već je fokus na okviru u kojem se ove promene dešavaju. Uzevši u obzir društveno-istorijski i savremeni društveni kontekst u Srbiji, sa aspekta činjeničnog stanja, sagledane su promene u režimima vlasničkih prava nad poljoprivrednim i građevinskim zemljištem i njihovi efekti. Ove promene odnose se na reatribuciju/redefinisanje vlasničkih prava, restituciju i privatizaciju. Pri tome, daje se kritička analiza kompleksnog regulatornog okvira u ovom domenu, uz naglašenu regulatornu ulogu prostornog planiranja u Srbiji. Najzad, istraživane veze između planiranja načina korišćenja zemljišta i vlasništva nad zemljištem konkretno su sagledane i stavljene u kontekst iii specifičnog prostora – područja obimne površinske eksploatacije Kolubarskog lignitskog basena u kojem se, u smislu prostornog obuhvata, dešavaju obimne i intenzivne promene uz višestruke konflikte u prostoru. Pošto planiranje ovog područja najpre treba da obezbedi zaštitu i ostvarivanje javnih interesa, na način na koji omogućuje i ostvarivanje najvećeg broja grupnih i individualnih interesa, s jedne strane, principi u planiranju odnose se na racionalno korišćenje poljoprivrednog zemljišta i što kraće vreme njegovog zauzimanja za rudarske aktivnosti, uz efikasnu sanaciju i rekultivaciju po završetku eksploatacije, pri čemu, s druge strane, planiranje nužno utiče na imovinsko-pravne odnose na zemljištu. Sumirajući prethodna pitanja, a na osnovu analize regulatornog okvira i podataka iz obimne planske, studijske i dokumentacione građe, došlo se do zaključka da je smanjena efikasnost u rešavanju problema vlasničkih interesa u postupku pribavljanja poljoprivrednog zemljišta za potrebe rudarskih aktivnosti, te da su otvorena pitanja daljeg upravljanja rekultivisanim zemljištem i otežan mehanizam (re)uspostavljanja vlasničkih odnosa nad njim. Mada promene namene poljoprivrednog zemljišta jesu neminovne, one se moraju pažljivo planirati i usmeravati. Istaknuta potreba da se odgovarajuće mere za ograničavanje degradacije zemljišta moraju sprovoditi na svim nivoima podrazumeva da su za njihovo efektivno delovanje na lokalnom nivou, uz regulatornu politiku poput prostornog planiranja, neophodni i drugi instrumenti uređenja i upravljanja. Pregled literature, kao i sagledavanje regulativnog okvira još jednom su proverili polaznu konstataciju o tome da, iako su vlasnička prava veoma zaštićena, planiranje korišćenja zemljišta, odnosno planirani način korišćenja zemljišta, može ograničiti ova prava i interese. Na osnovu svega prethodno iznetog, ocenjuje se da je ovo istraživanje ukazalo na neka otvorena pitanja u oblasti regulative o korišćenju zemljišta u domaćoj praksi, dok je razmotrilo mogućnost uspostavljanja mehanizama za kontrolu iv i prevenciju negativnih ishoda promene načina korišćenja zemljišta i vlasništva nad njime.

Taking into consideration the complexity and multidisciplinarity of the land use issues, the subject of this doctoral dissertation is limited to land use changes and land ownership changes from the spatial planning aspect. The research has also comprised the components of the land policy related to this issues (land tenure, land administration, land acquisition, etc.). Spatial planning has fundamental impacts on land control as a legal instrument of the state for the realisation of the public interest. In this regard, the task of spatial planning is to find a balance between the owner’s right to use his/her land and the public interest, thus, in this sense, a link between the planning, legal framework and owner's rights to and interest in the land is crucial. A special attention in the doctoral dissertation is paid to the forms of limitation of the land ownership stemming from the state’s intervention aiming at the implementation of the public interest. The planning establishes the obligations and limitations on the land in respect of land use, thus, as a rule, it implies the limitations of the land ownership (e.g. through the change in ownership relations, obligation of protection, rules for land development, etc.) or full exemption in land use change for the public purposes, which also requires entry in land registry (real estate cadastre, etc.). At the same time, the doctoral dissertation investigates the methods and procedures of the recent approaches of strategic and integrated planning typical for sustainable planning and management of agricultural land. In this respect, there is an increasing need for evaluation of land resources in the process of vi planning, as well as for integration of recent approaches in the prevention of land degradation into this process, in order to adequately use the planning instruments for careful control of agricultural land use change. The doctoral dissertation is written in the form of scientific study, while the research is based on theoretical knowledge, but also on practical models, i.e. specific planning practices, strategies and approaches, as well as on wider institutional and structural analyses. One of the primary aims of the doctoral dissertation is to provide a platform of basic knowledge about the insufficiently investigated impacts of land use planning on land ownership in Serbia, primarily focusing on the agricultural land use changes. The strategic and normative regulations on the use and protection of agricultural land as a resource of common interest indicate the need for its priority protection. Given the primary research task, the land use changes have not been just expressed quantitatively, but the focus is on the framework in which the changes occur. Taking into consideration the socio-historical and contemporary social contexts in Serbia, the land ownership change over agricultural and urban land and their effects have been considered from the aspect of factual situation. These changes relate to the reattribution/redefinition of property rights, restitution and privatisation. In this regard, a critical analysis of the complex regulatory framework in this domain is given along with an emphasized regulatory role of spatial planning in Serbia. Finally, the investigated links between land use planning and land ownership have been specifically considered and placed into the context of a specific area – the large open-pit exploitation area in the Kolubara lignite basin in which, in terms of spatial coverage, large and intense changes take place along with multiple conflicts in space. Given that the planning of this area should first provide the protection and realisation of the public interest in a way that also enables the realisation of the greatest number of group and individual interests, on the one hand, the vii principles in planning relate to the rational agricultural land use and the shortest possible time for its occupation for the purpose of mining activities, along with an efficient land sanation and recultivation after the exploitation completion, whereby, on the other hand, the planning necessarily affects the property and legal relations with respect to the land. Recapitulating the previously - mentioned issues, and based on the analysis of the regulatory framework and data from a extensively planning, study and documentation material, it was concluded that there is a decreased efficiency in solving the problems of ownership interests in the process of the agricultural land acquisition for the purpose of mining activities, and that issues of further of recultivated land management and more difficult mechanism of (re)establishing the property rights relations over land have been opened. Although the changes in the agricultural land use are unavoidable, they must be carefully planned and directed. The highlighted need for implementing the appropriate measures for the limitation of land degradation at all levels implies that other instruments of development and management are also necessary for their efficiency at the local level, along with regulatory policy like spatial planning. An overview of the literature, as well as consideration of regulatory framework, have once again confirmed the initial observation that, although the property rights are very protected, the land use planning, i.e. the land use, can limit these rights and interests. Based on all above mentioned, it is estimated that this research has pointed out some open issues in the field of regulations on the land use in local practice, while it has considered the possibility for establishing the mechanisms for control and prevention of negative effects of land use changes and land ownership.

Mogućnosti GIS-a u upravljanju zaštićenim prirodnim dobrima

The possibilitis of GIS in management of natural protected areas:example of Vrsac mountains

Mogućnosti geografsko-infomacionih sistema su brojne i nedovoljno primenjivane u Srbiji. U ovoj disertaciji razmatrana je primena GIS-a u simuliranju stepena širenja šumskog požara i proceni erozije i taloženja zemljišta na Vršačkim planinama. Za izradu tematskih karata korišćen je terenutno najrazvijeniji besplatni programski paket GRASS GIS. Karte stepena širenja vatre dobijene su pomoću Rothermel-ove jednačine komandom r.ros. Kategorije ugroženosti od erozije kao i količine nanosa izračunate su pomoću revidirane univerzalne jednačine gubitka zemljišta (RUSLE) i metodom S. Gavrilovića a zatim su rezultati upoređeni sa iskazom kubatura geodetski snimljenih profila na lolakitetu brane “Široko bilo”. Predhodno su pripremljeni ulazni parametri u vidu rasterskih mapa: multispektralni satelitski snimak WorldView-2 , digitalni model visina, pedološka i geološka karta i karte vegetacijskih indeksa (vegetacijski indeks normalizovanih razlika – NDVI, indeks vlage WBI i indeks „starenja“- PSRI). Za određivanje faktora erodibilnosti zemljišta laboratorijski su obrađeni uzorci zemljišta, predhodno pozicionirani GPS uređajem kinematičkom metodom u realnom vremenu (RTK), dok su za faktor erozivnosti kiše korišćeni podaci o kišnim epizodama registrovanim na pluviografskim trakama u periodu od 1954. do 1983. godine na meteorološkoj stanici u Vršcu. Rezultati istraživanja potvrdili su pretpostavku da se besplatnim GIS-alatima mogu dobiti interoperabilne karte simulacije šumskih požara. Prosečne godišnje vrednosti gubitka zemljišta dobijene primenom obe metodologije svrstavaju istraživani lokalitet u istu kategoriju ugroženosti od erozije dok metoda S. Gavrilovića daje preciznije rezultate ukoliko se kao referentna vrednost uzme srednja godišnja vrednost nanosa na osnovu proračuna kubatura iskopa akumulacije na brani “Široko bilo”.

The possibilities of GIS are numerous but they not enough applied in Serbia. In this dissertation the implementation of GIS was considered in modelling of forest fires rate of spread and prediction of soil erosion and deposition in Vrsac Mountains. Thematic maps were created by the biggest open source software GRASS GIS. The maps of forest fires rate of spread were generated by command r.ros which applying the Rothermels equation. The categories of erosion and sediment amounts are calculated using the revised universal soil loss equation (RUSLE) and the method of S. Gavrilović and then the results were compared with the amount of excavated soil from the accumulation on place called “Široko bilo“. The multispectral satellite imagery WorldView-2, a digital elevation model, soil and geological map and maps of vegetation indices (Normalized Difference Vegetation Index - NDVI, WBI- Water Band Index and the Plant Senescence Reflectance Index - PSRI) were prepared as inputs in the form of raster maps. For the determination of soil erodibility, the soil samples were collected by GPS in real kinematic mode (RTK), and then were processed in laboratory while the coefficient of the erosivity of rainfall was calculated from rain gauges measurements from 1954. to 1983. at meteorological station in Vrsac. The assumption that the free GIS tools can provides interoperable maps of forest fires models was confirmed by this research. The average annual soil loss obtained from both methodologies are classified into same category of erosion but method of S. Gavrilović gives more accurate results if we take the average annual value from amount of excavated soil from the accumulation at place called “Široko bilo“ as reference value.

Didaktička transformacija geografskih sadržaja od I do IV razreda osnovne škole

Didactic transformation of geographical contents from 1st to 4th grade of primary education

Nova naučna otkrića u geografiji i njena transdisciplinarnost učinili su je značajnijom i zahtevaju preispitivanje i prevrednovanje geografije kao nastavnog predmeta čiji sadržaji se izučavaju na svim nivoima školovanja. Posebnu pažnju zaslužuju geografski sadržaji u osnovnoj školi, u kojoj se postavljaju temelji svemu što će se izučavati na kasnijim uzrastima. Njihov kvalitet zavisi od mnogih činilaca, a pre svega od nastavnog programa, materijalnih uslova, a najviše od stručnosti učiteljâ. Što se programa tiče, zahtevi se odnose na dobro odmerene i naučno utemeljene sadržaje koji se konstituišu transformacijom naučnih sadržaja u nastavne, a razlikuju se od njih po mnogim karakteristikama. Ove razlike nastaju zahvaljujući didaktičkom prilagođavanju geografskih naučnih sadržaja u sadržaje nastavnih predmeta Svet oko nas i Priroda i društvo, koji se izučavaju tokom prvog ciklusa osnovnog obrazovanja i vaspitanja. Prilikom sačinjavanja novih nastavnih programa, naučne sadržaje su u nastavne transformisale, po pravilu, komisije koje su imenovale prosvetne vlasti. Didaktičari su, kao i učitelji praktičari, na njih manje uticali. Vrednost ovako sačinjenih programa bila je u tome što su naučno zasnovani, ali su najčešće bili neodređeni i nedovoljno prilagođeni potrebama, interesovanjima i mogućnostima učenika. To je postajalo naročito vidljivo u mlađim razredima osnovne škole. Zato se ispostavilo da je potrebno naučno preispitati čitav proces transformacije naučnih sadržaja geografije u nastavne, uzimajući u obzir što više činilaca i aspekata ove složene problematike, kao što su vaspitni i obrazovni aspekt, didaktički aspekt, istorijski aspekt, sagledavanje do sada stečenih iskustava, poređenje sa iskustvima i postignućima razvijenih zemalja, kao i prikupljanje mišljenja i predloga učitelja, koji ostvaruju nastavni program, i učenika, sa kojima se on realizuje. Za potrebe ovog istraživanja, koje podrazumeva istorijsku, komparativnu i deskriptivnu metodu, konstruisani su posebni istraživački instrumenti (navedeni na str. 77) potrebni za svestrano sagledavanje problematike o kojoj je reč. Oni su ukršteni sa mišljenjima učenika i nastavnika o geografskim sadržajima sa kojima se upoznaju i procenjeni na osnovu didaktičkih kriterijuma koje definiše savremena pedagogija. Najvažniji nalazi istraživanja o kome je reč jesu:  Da bi geografski sadržaji koji se izučavaju u mlađim razredima osnovne škole realizovali svoje značajne obrazovne i vaspitne kapacitete, potrebno ih je na odgovarajući način didaktički transformisati, što u predmetima Svet oko nas i Priroda i društvo, koji se izučavaju u prva četiri razreda osnovne škole, nije učinjeno na najbolji način.  Da bi se poboljšalo stanje u tom pogledu proučen je istorijat nastave geografskih sadržaja u Srbiji, upoređena ova nastava sa odgovarajućom nastavom u razvijenim evropskim zemljama, opisani i vrednovani uslovi u kojima se odvija nastava, analizirani udžbenici i prikupljena mišljenja učitelja koji drže nastavu pomenutih predmeta. Posebno je ispitano i mišljenje učenika o njihovom aktuelnom programu.  U nastavnim predmetima Svet oko nas i Priroda i društvo nedovoljno se koriste vaspitni potencijali geografskih sadržaja, naročito kad je reč o ekologiji, razvoju patriotizma i formiranju naučnog pogleda na svet. Sadržaji, osim toga, nedovoljno prate nova otkrića u geografiji kao nauci i pri tome se nedovoljno koriste savremene metode, sredstva i oblici rada, iako ima pokušaja da se u nastavi više koriste informatičke tehnologije karakteristične za savremenu školu.  Učitelji su uglavnom dobro pripremljeni za svoj posao, posebno oni sa bar nekoliko godina iskustva, koji su spremni za prihvatanje novina u nastavi, naročito za aktivnu ulogu učenika u nastavi. Drugi deo nastavnog trougla, koji, pored nastavnika i nastavnog programa, čine učenici, pokazao je potrebnu motivaciju za upoznavanje geografskih sadržaja i interesovanje za određene teme proistekle iz njih. Istovremeno se u nastavnom programu javljaju neki sadržaji koji su im teški za razumevanje (npr. orijentacija u prostoru), a još više - primenu u praksi.  Uz podatke o najvažnijim faktorima koji utiču na uspešnu transformaciju naučnih sadržaja geografije u nastavne, prikupljeno je mnoštvo podataka i mišljenja o načinima ove transformacije na osnovu kojih se može unaprediti nastava geografskih sadržaja u osnovnoj školi, što je važno učiniti s obzirom na sve veći značaj geografske kulture u skoro svim domenima ljudskog života i rada.

New scientific discoveries in Geography and its transdisciplinarity have made this subject more significant, requiring a reconsideration and reassessment of Geography as a school subject whose contents are taught and learned at all levels of school education. The geographic contents in primary school deserve special attention, given that primary education creates foundations for all subjects to be taught in higher grades. Their quality depends on various factors, such as the syllabus and the material conditions, and most of all on the teachers’ competence. With regard to the syllabus, the requirements refer to well balanced and scientifically based contents constituted by the transformation of scientific contents into educational ones, which differ in a number of characteristics. Such differences are the product of a didactic adjustment of geographic scientific contents to the contents of the school subjects The World Around Us and Social, Environmental and Scientific Education, which are taught during the first cycle of primary school education. As a rule, in the process of creating new syllabi, it is the commissions nominated by educational authorities that transform the scientific contents into educational ones. Didactic and teaching practitioners have far less influence on the choice of these contents. The value of syllabi created in this way lies in the fact that they are scientifically based. However, in most cases such syllabi have proved to be indefinite and insufficiently adapted to students’ needs, interests and capacities. This has been particularly noticeable in the lower grades of primary education. There fore, a scientific reconsideration of the complete process of transformation of geographical scientific contents into educational ones proved to be necessary. Various factors and aspects of this complex issue need to be taken into account during the process, such as the pedagogical, didactic and historical aspects, empirical results, comparisons with the experience and achievements in developed countries, including collecting the opinions and suggestions of the teachers in charge of implementing the syllabus, and the target groups of students. For the purpose of this research, which combines the historical, comparative and descriptive methods, special research instruments were designed (described on page 77) in order to thoroughly consider the topic in question. These instruments have been used to study the opinions of pupils and teachers regarding the geographical contents they have learnt, and analyzed according to the didactic criteria defined by modern pedagogy. The most important results of the research are the following:  In order to yield full educational and pedagogical effectiveness, geographical contents taught in lower grades of primary education need to be transformed in an adequate didactic way, which has not been best done within the school subjects The World Around Us and Social, Environmental and Scientific Education, taught in the first four grades of primary education.  With the aim of improving the current status of the subject, the history of teaching geographical contents in Serbia was examined, this teaching subject was compared with those in the developed European countries, the conditions for teaching this subject were described and evaluated, text books were analyzed, and the opinions of teachers who teach the subjects in question were collected. Pupils’ opinions on their current syllabus were given special care.  The school subjects The World Around Us and Social, Environmental and Scientific Education insufficiently use the pedagogical potentials of geographical contents, especially regarding ecology, developing of patriotism and forming a scientific view of the world. Additionally, the contents insufficiently follow the latest discoveries in Geography as a science, and often fail to include modern teaching methods, resources and interaction patterns, despite sporadic attempts of using the information technologies characteristic of contemporary school.  Teachers are mainly well-prepared for their work, especially those who have had at least several years of experience, and who readily accept teaching innovations, especially regarding the active role of students. Students, as another side of the educational triangle besides the teachers and the syllabus, have shown the necessary motivation for learning geographical contents and a specific interest in certain accompanying topics. At the same time, they find certain contents of the syllabus hard to understand (e.g. spatial orientation), and even harder to practically apply.  Along with the data on the most important factors for a successful transformation of geographical scientific contents into educational ones, numerous data and opinions about the possible ways of such a transformation have been collected, based on which the teaching of geographical contents in primary schools can be improved. This is an important thing to do, having in mind the growing importance of geographical culture in almost all domains of human life and work.

Nastanak, karakteristike i mogućnosti revitalizacije braunfilda velike površine u Republici Srpskoj

Genesis, characteristics and revitalization possibilities of large-scale brownfield sites in the Republic of Srpska

Braunfildi (eng. brownfields) predstavljaju jedan od globalnih prostornih fenomena današnjice, prvenstveno povezan sa promjenama u privrednoj strukturi u razvijenim zemljama Zapadne Evrope i Sjeverne Amerike, te tranzicionim zemljama Centralne i Jugoistočne Evrope. Pod njima se generalno podrazumjevaju površine (zemljište) i objekti u urbanizovanim područjima koji su izgubili svoj prvobitni način korišćenja ili su značajno potkorišćeni. Kao prostorno najistaknutiji oblik braunfilda ističu se braunfildi velike površine. Geneza braunfilda velike površine Republike Srpske (RS) se ne razlikuje od nastanka ostalih tipova braunfilda u Republici Srpskoj. Pored uobičajenih genetskih faktora (prestruktuiranje svjetske privrede) na nastanak braunfilda u cjelini veliki uticaj su imali ratni sukobi i ekonomske sankcije Ujedinjenih nacija tokom 1990 – ih godina protiv tadašnje Savezne Republike Jugoslavije (Srbije i Crne Gore) i Republike Srpske. Za potrebe ovog rada urađeno je praktično istraživanje čiji je rezultat identifikacija braunfilda sa površinom iznad 4 ha (braunfildi velike površine) u Republici Srpskoj na dan 31.12.2013. godine. Ukupno je identifikovano 49 braunfilda velike površine na teritoriji Republike Srpske koji su analizirani sa aspekta njihovih prostornih, imovinsko - pravnih, ekonomskih, ekoloških i socio - psiholoških karakteristika. Najveća koncentracija braunfilda velike površine RS je prisutna u mezoregiji Istočno Sarajevo, gdje se nalazi 38.78 % ovih braunfilda, odnosno 19 lokacija. Klasifikacije braunfilda velike površine RS prema namjeni i dužini trajanja statusa su pokazale da su najzastupljeniji industrijski braunfildi velike površine sa 57.14 %, odnosno braunfildi velike površine sa dužinom trajanja statusa 5 - 10 godina sa 44.9 %. Proces revitalizacije ili reaktiviranja braunfilda velike površine na teritoriji RS je objašnjen na osnovu studije slučaja koja je obuhvatila VI primjere industrijske zone "Maglić" Brod na Drini u opštini Foča i privrednog pogona "Udarnik" Bjelajce u opštini Mrkonjić Grad...

Brownfield sites or brownfields represent a global spatial phenomenon owing their origin primarily to changes in economic structure of the developed countries in Western Europe and North America as well as the transition countries of Central and Southeastern countries. Generally speaking, a brownfield sites can be defined as urbanized zone areas and facilities which have lost their original use or become significantly underused. In terms of their spatial relevance, large-scale brownfield sites are found to be the most relevant ones. The genesis of large-scale brownfields i n t he Republic o f Srpska ( RS) i s by no means a ny d ifferent f rom t he genesis o f o ther b rownfield t ypes i n R S. I n p art due the most common factors (worldwide economic restructuring processes), the origin of brownfield sites is also related to armed conflicts and UN imposed sanction against the Federal Republic of Yugoslavia (Serbia and Montenegro) and the Republic of Srpska in the 1990s. A research, conducted for this paper on 31 December 2013, has resulted in the identification of brownfield sites with area over 4 ha (large-scale brownfields). The total of 49 large-scale brownfields has been identified in the Republic of Srpska; they have been analyzed in terms of their spatial relevance, real estate legal status, economic, ecological and socio-psychological characteristics. The largest proportion of such sites has been distinguished in the mesoregion of Istočno Sarajevo (Eastern Sarajevo), i.e. 38.78 % of the total number or 19 largescale brownfield sites. The RS large-scale brownfield classification, tailored alongside their utilization and the length of status, has revealed that the most common brownfields are industrial brownfield sites (57.14 %); in terms of the length of status, the most common sites are brownfields existing 5 – 10 years (44.9 %). The process of revitalization or reactivation of large-scale brownfield sites in the Republic of Srpska has been exemplified by the case studies of industrial zone "Maglić" Brod na Drini, Foča municipality and plant "Udarnik" Bjelajce, Mrkonjić Grad municipality. The most recent data treating the issue of increase of the number in brownfield formation compared to the number of revitalized brownfield sites (1 January – VIII 30 June 2014) have shown that, after years of progression, the total number of new sites formation has stagnated, i.e. the increment of large-scale brownfields formation is equal to the number of brownfield sites revitalization...

Polne razlike u regulaciji ekspresije i aktivnosti inducibilne azot-monoksid-sintaze i natrijum-kalijumove pumpe u jetri gojaznih pacova

Sex differences in regulation of expression and activity of inducible nitric oxid synthase and sodium-potassium pump in liver of obese rats.

Gojaznost i posledično poremećen metabolizam lipida i glukoze u jetri su glavni faktori rizika za razvoj bolesti jetre. Polne razlike u gojaznosti i razvoju rezistencije na insulin (IR) i nealkoholne bolesti masne jetre (NAFLD) pripisuju se estrogenima, ali mehanizmi kojima ovi hormoni ostvaruju pomenute efekte nisu dovoljno istraženi. Pored toga što ostvaruju genomske efekte, estrogeni aktiviraju i signalne molekule u citoplazmi: fosfatidilinozitol 3-kinazu (PI3K), protein kinazu B (Akt), Rho familiju malih GTP vezujućih proteina (Rho), kao i njihove nishodne efektore, Rho-vezane protein kinaze (ROCK), zatim AMP-aktivirajuće protein kinaze (AMPK) i kinaze regulisane ekstraćelijskim signalima (ERK1/2). Dosadašnja istraživanja su pokazala da, pored protektivne uloge koju inducibilna azot-monoksid-sintaza (iNOS) ima u jetri tokom različitih procesa (sepsa i ishemija), poremećaj u regulaciji njene ekspresije i aktivnosti mogu biti uključeni u razvoj IR u gojaznosti. Jedna od pratećih komplikacija IR je i poremećaj u regulaciji ekspresije i aktivnosti natrijum-kalijum adenozin trifosfataze (Na+/K+-ATP-aza), koja učestvuje u realizaciji brojnih procesa u jetri. Poznato je da estradiol reguliše ekspresiju iNOS i Na+/K+-ATPaze, ali podaci koji ukazuju na polne razlike u regulaciji ekspresije i aktivnosti ovih enzima u jetri gojaznih životinja nedostaju u literaturi. U eksperimentima ove doktorske disertacije korišćeni su adultne ženke i mužjaci pacova Wistar soja. Jedna grupa pacova je hranjena standardnom laboratorijskom hranom (kontrolni pacovi), a druga standardnom laboratorijskom hranom obogaćenom sa 42% masti (gojazni pacovi). Nakon 10 nedelja životinje su žrtvovane, izolovane su jetre, a iz pune krvi su izdvajani serum i plazma. U serumu pacova određivane su koncentracije: glukoze, insulina, ukupnog holesterola, dok je u plazmi određivana koncentracija slobodnih masnih kiselina (SMK) i koncentracija nitrita (NO2 -) i nitrata (NO3 -), kao krajnjih produkata NO. U lizatu jetre pacova određivana je koncentracija glukoze, holesterola i SMK, kao i aktivnost Rho proteina. Aktivnost Na+/K+-ATPaze je određivana u frakciji plazma membrana ćelija jetre. Nivo iRNK za iNOS i α1 subjedinicu Na+/K+-ATPaze određivan je metodom qPCR. Western blot metodom određivana je količina α1 subjedinice Na+/K+-ATPaze, GLUT2 i FAT/CD36 u frakciji plazma membrana, dok je nivo ekspresije iNOS, NFκB IRS-1, PI3K-p85 i PI3K-p110, RhoA, ROCK1 i ROCK2, ERα i ERβ, kao i nivo fosforilacije mTOR, PDK1, Akt, ERK1/2 i AMPKα1 kinaza određivan u lizatima ćelija jetre. Asocijacija IRS-1 proteina sa PI3K-p85 u lizatu jetre određivana je metodom koimunoprecipitacije. Rezultati ove doktorske disertacije pokazuju da, za razliku od mužjaka, kod ženki pacova nema promena u koncentraciji insulina u serumu i vrednosti HOMA indeksa, dok je koncentracija glukoze u serumu smanjena. U membranskoj frakciji proteina jetre nivo GLUT2 proteina je smanjen kod gojaznih pacova oba pola, dok je nivo FAT/CD36 proteina smanjen kod gojaznih ženki, a povećan kod gojaznih mužjaka pacova. Nivo iRNK za iNOS i koncentracija NO2 -/NO3 - je povećana, a nivoa iNOS proteina smanjen samo kod gojaznih mužjaka pacova. Nivo proteina α1-Na+/K+-ATPaze i aktivnost Na+/K+-ATPaze su smanjeni kod gojaznih pacova oba pola, dok je relativna ekspresija gena za α1 subjedinicu Na+/K+-ATPaze smanjenja samo kod gojaznih mužjaka pacova. Nivo fosforilacije PDK1 i Akt na Thr308 smanjen je u jetri pacova oba pola, dok je nivo fosforilacije mTOR i Akt na Ser473 smanjen samo u jetri gojaznih mužjaka pacova. Nivo fosforilacije ERK1/2 i AMPKα1 je povećan u jetri gojaznih ženki, a smanjen u jetri gojaznih mužjaka. Takođe, povećanje aktivnosti Rho proteina uočeno je samo u jetri gojaznih mužjaka, dok je nivo RhoA proteina smanjen samo u jetri gojaznih ženki pacova. Rezultati u okviru ove doktorske disertacije pokazuju da HF ishrana dovodi do razvoja sistemske IR i poremećaja metabolizma glukoze i lipida samo u jetri mužjaka pacova. Takođe, pokazane su polne razlike u regulaciji ekspresije i aktivnosti iNOS i Na+/K+-ATP-aze, koja je posredovana učešćem signalnih molekula mTOR, Akt, ERK1/2, AMPKα i RhoA. Rezultati ove doktorske disertacije doprinose razumevanju polnih razlika u razvoju IR i mogu imati primenu u razvoju novih terapijskih pristupa u lečenju komplikacija u gojaznosti.

Obesity and altered hepatic lipid and glucose metabolism are main risk factors for the development of liver diseases. Sex differences in obesity and development of insulin resistance (IR) and non-alcoholic fatty liver disease (NAFLD) are attributed to estrogens, but the exact mechanisms of their effects have not been fully understood. In addition to genomic effects, estrogens also activate signaling molecules in the cytoplasm: phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt), Rho family of small GTP binding proteins (Rho), as well as their effectors, Rho-associated protein kinases (ROCK), AMP-activating protein kinase (AMPK) and extracellular signal- regulated kinases 1 and 2 (ERK1/2). Besides the protective role of inducible nitric oxide synthase (iNOS) in the liver during various processes (sepsis and ischemia), the altered expression and activity of this enzyme may be involved in the development of IR in obesity. One of the common comorbidities of obesity-induced IR is altered expression and activity of sodium/potassium-adenosine triphosphatase (Na+/K+-ATPase), which participates in numerous processes in the liver. It is known that estradiol regulates the expression of iNOS and Na+/K+-ATPase, but there is no evidence on sex-specific differences in hepatic iNOS and Na+/K+-ATPase expression/activity in obese animals. For the experiments of this doctoral dissertation adult female and male Wistar rats were used. Control groups of rats were fed standard laboratory diets (control rats) and the other two groups were fed standard laboratory food enriched with 42% fat (obese rats). After 10 weeks, the animals were sacrificed, and livers, serum and plasma were isolated. Serum glucose, insulin and total cholesterol concentrations were determined, as well as plasma free fatty acids (FFA) and nitrite (NO2 -) and nitrate (NO3 - ) concentrations. The concentrations of glucose, cholesterol and FFA, as well as the activity of Rho proteins, were determined in liver lysates. The hepatic Na+/K+-ATPase activity was determined in the plasma membrane fraction. The iNOS and α1 subunit of Na+/K+-ATPase mRNA levels were determined by qRT-PCR. Western blot method was used to determine protein levels of α1-Na+/K+-ATPase, GLUT2 and FAT/CD36 in the plasma membrane fraction, while protein levels of iNOS, NFκB IRS-1, PI3K-p85 and PI3K-p110, RhoA, ROCK1 and ROCK2, ERα and ERβ, as well as phosphorylation levels of mTOR, PDK1, Akt, ERK1/2 and AMPKα1 were determined in liver lysates. The association of IRS-1/PI3K-p85 in liver lysates was determined by co- immunoprecipitation. The results of this doctoral dissertation show that, unlike males, there are no changes in serum insulin levels and HOMA indices in female rats, while serum glucose levels are reduced. GLUT2 protein level in the plasma membrane fraction in liver was decraesed in obese rats of both sexes, while FAT/CD36 protein level was decreased in obese females, and increased in obese male rats. The iNOS mRNA level in liver and plasma NO2 -/NO3 - concentration were increased, and iNOS protein level was decreased only in obese male rats. The hepatic α1-Na+/K+-ATPase protein level and Na+/K+- ATPase activity were decreased in obese rats of both sexes, while α1-Na+/K+-ATPase mRNA level was decreased only in livers of obese male rats. The phosphorylation levels of PDK1 and Akt (Thr308) were reduced in livers both female and male obese rats, while the phosphorylation levels of mTOR and Akt (Ser473) were reduced only in livers of obese male rats. The phosphorylation level of ERK1/2 and AMPKα1 was increased in livers of obese females and decreased in livers of obese males. Also, the increase of hepatic Rho activity was observed only in obese male rats, while the hepatic RhoA protein level was decreased only in obese female rats. The results of this doctoral dissertation show that HF diet leads to the development of systemic IR and disturbance of hepatic glucose and lipid metabolism only in male rats. Also, obtained results show sex specific differences in the regulation of iNOS and Na+/K+-ATPase expression/activity which are mediated by the participation of mTOR, Akt, ERK1 / 2, AMPKα and RhoA signaling molecules. These results contribute to better understanding of pathogenesis and sex differences in obesity- induced IR in the liver and may lead to discovering new therapeutic approaches in the treatment of obesity complications.

Kontraciklična ekonomska politika u prevazilaženju privrednih fluktuacija

Countercyclical economic policy in overcoming economic fluctuations

Predmet doktorske disertacije pod nazivom „Kontraciklična ekonomska politika u prevazilaženju privrednih fluktuacija“ je teorijska i empirijska analiza kontraciklične makroekonomske politike i njene primene u prevazilaženju cikličnih fluktuacija ekonomske aktivnosti u razvijenim tržišnim ekonomijama s jedne, i u ekonomijama u razvoju i ekonomijama sa nastajućim tržištima, sa druge strane. Tema disertacije je obrađena na celovit način koji je istovremeno uključio i predstavljanje teorijsko – metodološke osnove kontraciklične makroekonomske politike i rezultate empirijskih istraživanja koji ilustruju njenu primenu u razvijenim tržišnim ekonomijama, ekonomijama u razvoju te ekonomijama sa nastajućim tržištima, kao i empirijsko istraživanje o cikličnom karakteru ekonomske politike u Srbiji. Teorijske osnove kontraciklične ekonomske politike obuhvatile su instrumente i mere kontraciklične ekonomske politike i načine i mehanizme njihovog delovanja u prevazilaženju cikličnih privrednih fluktuacija koji su definisani u okviru teorije ekonomske politike. Pored toga, teorijske osnove su obuhvatile i stavove o uzrocima, transmisionim mehanizmima, načinima manifestacije i posledicama ciklične makroekonomske nestabilnosti koji su formulisani u savremenim makroekonomskim teorijama i njihove preporuke za vođenje kontraciklične ekonomske politike. Metodološke osnove kontraciklične politike obuhvatile su predstavljanje metoda statistike i ekonometrije koje se koriste u savremenim istraživanjima poslovnih ciklusa i cikličnoj analizi ekonomske aktivnosti. Nakon predstavljanja teorijsko – metodološke osnove kontraciklične ekonomske politike, disertacija se fokusirala na primenu kontraciklične ekonomske politike u savremenim tržišnim ekonomijama i ekonomijama u razvoju te ekonomijama sa nastajućim tržištima i na rezultate empirijskih istraživanja o karakteristikama poslovnih ciklusa i ekonomske politike u ovim ekonomijama. Rezultati ovih istraživanja prikazani su u disertaciji, pri čemu je izvršena njihova komparativna analiza sa posebnim naglaskom na uspešnost primene i efekte pojedinih mera kontraciklične ekonomske politike u različitim ekonomijama, uz zaključak da se iskustva ekonomija sa nastajućim tržištima u pogledu primene mera kontraciklične ekonomske politike mogu koristiti u procesima formulisanja i implementacije kontraciklične ekonomske politike u Srbiji. U nastavku disertacije predstavljeno je empirijsko istraživanje čiji je cilj bio da se ispita ciklični karakter ekonomske politike u Srbiji u periodu 2001-2011. godine. Istraživanje se sastojalo iz dva dela. U prvom delu istraživanja identifikovane su tačke prekretnice i ciklusi rasta u ekonomskoj aktivnosti Srbije u periodu 2001-2011. i izvršena je ciklična analiza ekonomske aktivnosti. Zatim je izvršeno poređenje sa cikličnim kretanjem ekonomske aktivnosti zemalja Evropske unije (Zone evra) kako bi se ispitalo odakle potiču ekonomske fluktuacije i da li su ciklusi u Srbiji posledica specifičnih okolnosti i događaja u ekonomskom, društvenom i političkom životu Srbije ili su posledica transmisije ciklusa iz inostranstva. Rezultati su pokazali da tačke prekretnice ciklusa Zone evra prethode tačkama prekretnicama srpske privrede i da je ovo prethođenje vrlo kratko, tako da se ekonomske fluktuacije iz zemalja Zone evra prenose na Srbiju vrlo brzo, praktično u okviru istog kvartala. Zaključak prvog dela empirijskog istraživanja bio je da postoji povezanost između poslovnih ciklusa zemalja Evropske unije i Srbije i IV da postoji potreba za aktivnom kontracikličnom makroekonomskom politikom u Srbiji koja proizilazi iz ove povezanosti i podložnosti Srbije kao male, otvorene ekonomije uticajima iz međunarodnog okruženja. U drugom delu empirijskog istraživanja izvršeno je ispitivanje cikličnog karaktera ekonomske politike u Srbiji. Ispitivanje cikličnog karaktera ekonomske politike sastojalo se od analize cikličnog kretanja značajnih makroekonomskih varijabli – indikatora monetarne i fiskalne politike koje odražavaju mere ekonomske politike u Srbiji. Na osnovu analize cikličnog kretanja ovih varijabli i korelacije sa agregatnim ciklusom, ispitano je da li je ekonomska politika od 2001 – 2011. godine bila kontraciklična ili prociklična i u kojim svojim segmentima. U istraživanju su korišćene sledeće varijable: novčana masa M2, indeks cena na malo i realan efektivni devizni kurs na strani monetarne i serije javnih prihoda i javnih rashoda – primanja i izdavanja budžeta Republike Srbije, na strani fiskalne politike. Sezonska komponenta iz serija eliminisana je primenom X11 ARIMA metoda, dok je kao metod za ocenu trenda korišćen Hodrick – Prescott – ov (HP) filter. Ciklična komponenta serija dobijena je deljenjem vrednosti serija trendom i množenjem sa 100. U oceni cikličnog karaktera varijabli i ekonomske politike koju varijabla reprezentuje korišćen je uporedni grafički prikaz ciklične komponente varijabli i bruto domaćeg proizvoda i posmatrana je kros-korelacija između ciklične komponente varijabli i bruto domaćeg proizvoda na različitim pomacima. Rezultati empirijskog istraživanja su pokazali da je fiskalna politika u posmatranom periodu delovala kontraciklično. Fiskalna izdavanja deluju kontraciklično i sa pomakom, nakon šest kvartala, dok su primanja budžeta prociklična. Fiskalni impuls, konstruisan kao odnos izdavanja i primanja budžeta, takođe pokazuje kontracikličan karakter i vodi. Rezultat odgovara predviđanjima u okviru IS-LM modela sa nesavršenom mobilnošću kapitala gde je fiskalna ekspanzija u uslovima priliva kapitala praćena apresijacijom valute što vremenom dovodi do usporavanja rasta. Ciklično dejstvo novčane mase M2 u sprskoj privredi je unekoliko protivrečno, ali sudeći po rezultatima kros-korelacione analize i Grejndžerovog testa uzročnosti, novčana masa je prociklična i zaostaje za promenama u ekonomskoj aktivnosti. Realan efektivni devizni kurs deluje kontraciklično, nakon osam kvartala, a rezultat takođe odgovara predviđanjima u okviru IS-LM modela sa nesavršenom mobilnošću kapitala gde apresijacija kursa u uslovima priliva kapitala vremenom dovodi do pada u autputu. Posebna pažnja u istraživanju posvećena je cikličnom kretanju cena i korelaciji cena sa agregatnim ciklusom. Naime, ukoliko je koeficijent korelacije cena i agregatnog ciklusa negativan, cene su kontraciklične a uzroci ekonomskih fluktuacija su na strani agregatne ponude; u suprotnom, ukoliko je korelacija pozitivna, uzroci fluktuacija su na strani agregatne tražnje. Ovo je teorijska postavka, a cilj istraživanja je bio da se utvrdi da li bi se ova postavka mogla koristiti prilikom utvrđivanja uzroka cikličnih fluktuacija i za Srbiju. Rezultati emprijskog istraživanja su pokazali da su cene su prociklične i kasne za ciklusima u agregatnoj ekonomskoj aktivnosti, što ukazuje da su uzroci cikličnih fluktuacija u periodu od 2001- 2011. godine u Srbiji bili na strani agregatne tražnje. S obzirom na rezultate empirijskog istraživanja, opažene cikluse u ekonomskoj aktivnosti Srbije i posledice transmisije međunarodnih ciklusa a naročito poslednje svetske finansijske i ekonomske krize, u disertaciji je ukazano da postoji potreba za aktivnom kontracikličnom politikom u Srbiji. Predložene mere u oblasti kontraciklične ekonomske politike obuhvataju mere spoljnotrgovinske politike kojima bi se izvršila diversifikacija spoljnotrgovinske razmene i ublažila podložnost ekonomije inostranim ciklusima. S obzirom na to da su uzroci cikličnih fluktuacija na strani agregatne tražnje, mere kontraciklične ekonomske V politike treba da budu usmerene na upravljanje agregatnom tražnjom, ublažavanje fluktuacija i produžavanje faza ekspanzije. Neophodno je definisati opšti pristup, principe i strategiju vođenja kontraciklične politike. Pristup bi trebao da bude proaktivan i zasnovan na makroekonomskoj analizi i predviđanju i na primeni savremenih, inovativnih pristupa poslovnim ciklusima koji obuhvataju: iznalaženje pojedinačnih rešenja za izlazak iz krize za svaku zemlju, istraživanje i pronalaženje novih izvora rasta, analizu pojedinačnog ciklusa, njegovih uzroka, karakteristika i transmisije i konstantno vrednovanje makroekonomske politike u svetlu novih okolnosti, specifičnih uzroka i mehanizama transmisije svakog pojedinačnog ciklusa.

The subject of a doctoral dissertation entitled “Countercyclical economic policy in overcoming economic fluctuations” is a theoretical and empirical analysis of countercyclical macroeconomic policy and its use in overcoming cyclical fluctuations in economic activity in developed economies on the one hand, and developing economies and economies in emerging markets, on the other hand. The dissertation is addressed in a comprehensive manner that involves both the presentation of the theoretical and methodological foundations of countercyclical macroeconomic policies, and the presentation of the results of empirical studies that illustrate the use of the countercyclical economic policy in developed market economies, developing economies and economies in emerging markets, together with the empirical study on cyclical properties of economic policy in Serbia. Theoretical foundations of countercyclical economic policy have encompassed an overview of counter-cyclical economic policy instruments and measures as they are defined in the theory of economic policy and how they affect the economy in overcoming cyclical economic fluctuations. In addition, theoretical foundations have included different opinions of modern macroeconomic theories concerning what causes cyclical fluctuations, how they manifest, what the mechanisms of their propagations are, as well as economic policy suggestions. Methodological foundations have included the presentation of statistical and econometric methods used in contemporary studies of business cycles and in the cyclical analysis. After presenting the theoretical and methodological foundations of countercyclical economic policies, dissertation focuses on the use of counter-cyclical economic policy in developed economies, developing economies and economies in emerging markets and on the results of empirical researches on cyclical features of business cycles and economic policy in these economies. The results of these researches are presented and have been analyzed with special emphasis on the efficiency of measures of counter-cyclical economic policy and their effects on different types of economies. The conclusion is that the experience of emerging market economies with respect to the implementation of countercyclical economic policy can be used in the process of formulation and implementation of counter-cyclical economic policy in Serbia. Furthermore, the results of an empirical study whose aim was to examine the cyclical properties of economic policy in Serbia in the period 2001-2011 are also presented. Research consists of two parts. In the first part of the study the turning points and growth cycles in economic activity in Serbia in the period 2001-2011 were identified and the cyclic analysis of economic activity was performed. Then, the cyclical fluctuations in economic activity of the European Union (euro zone) were compared with those in Serbia in order to examine whether the cycles in Serbia are the result of specific circumstances and developments in the economic, social and political environment or the consequence of the transmission cycle from abroad. The empirical study has shown that the turning points in cycles of euro area precede the turning points of the Serbian economy and that this precedence is very short, so that economic fluctuations of the euro zone are transmitted on Serbia very fast, that is, within the same quarter. The conclusions of the first part of the empirical study are that there is a link VII between the business cycles of the European Union and that there is a need for counter- cyclical macroeconomic policies in Serbia stemming from this relationship and vulnerability of Serbia as a small economy open to influences from abroad. In the second part of the empirical study the cyclical features of economic policy in Serbia have been explored. The study involved an analysis of cyclical properties of important macroeconomic variables, that is, of monetary and fiscal policy indicators which are representative of the economic policy in Serbia. Based on the analysis of cyclical properties of these variables and their correlations with aggregate cycle, we examined whether the economic policy from 2001 - 2011 was pro-cyclical or counter-cyclical and in which areas (monetary policy, fiscal policy, etc.). The following variables have been examined: money supply M2, the retail price index and the real effective exchange rate as the monetary policy variables, and a series of public revenue and public expenditure – government income and government expenditure, as the fiscal policy variables. The series are seasonally adjusted using the X11 ARIMA method, while the Hodrick- Prescott (HP) filter has been used as a method for assessing the trend. The cyclical component of the series is obtained by dividing the value of the series by trend and then multiplying them by 100. In assessing the cyclical properties of variables and economic policy a comparative graphical representation of variables and cyclical components of GDP have been used and a cross-correlation between the cyclical component of the variables and the gross domestic product in different shifts has been analyzed. The results of empirical studies have shown that fiscal policy in this period was counter- cyclical. Government spending affects the economy with some lag, after six quarters, while the government revenues are pro-cyclical. A fiscal impulse, constructed as the ratio of government income and government expenditure, also shows countercyclical properties and leads the aggregate cycle. The result corresponds to the predictions of the IS-LM model with imperfect capital mobility, where fiscal expansion accompanied by the capital inflows is followed by the currency appreciation, which eventually leads to slowdown in growth. Cyclical effect of M2 in the Serbian economy is somewhat contradictory, but judging by the results of cross-correlation analysis and Granger causality test, the money supply is pro-cyclical, lagging behind the changes in economic activity. Real effective exchange rate is acting in a counter manner after eight quarters. This result also corresponds to the predictions of the IS-LM model with imperfect capital mobility where the appreciation of the exchange rate accompanied by the capital inflows eventually leads to the fall in output. Special attention in the study has been paid to the cyclical properties of prices and their correlation with the aggregate cycle. Namely, if prices are negatively correlated with the aggregate cycle, they are countercyclical and the causes of economic fluctuations are on the supply side, otherwise, if the correlation is positive, the causes of the fluctuations are on the demand side. This is a theoretical postulate, and the goal was to determine whether this postulate can be used in determining the causes of cyclical fluctuations in Serbia. The study has shown that prices are pro-cyclical and lag behind the cycles, which is the indicator that the causes of cyclical fluctuations in Serbia in the period from 2001 to 2011 were on the demand side. Given the results obtained in the empirical study, the perceived cycles in economic activity in Serbia and the consequences of international transmission cycle, especially the last global financial and economic crisis, the doctoral thesis points out the need for active countercyclical policy in Serbia. The proposed measures of counter- cyclical economic policies include measures of trade policy that would enable diversification of foreign trade and mitigate vulnerability to international economic VIII cycles. Given that the causes of cyclical fluctuations are on the demand side, countercyclical economic policy should be focused on aggregate demand management, reducing fluctuations and extending the phase of expansions. It is necessary to define a general approach, the principles and strategy for management of counter-cyclical policies. The general approach should be proactive and based on macroeconomic analysis and forecasting, and the application of modern, innovative approaches to business cycles, which include: finding an individual solution to overcome the crisis in each country, exploring and finding new sources of growth, analyzing a particular cycle, its causes, characteristics and transmission and constant evaluation of macroeconomic policy in the light of new circumstances, specific causes and mechanisms of transmission of each cycle.

Demografski i socijalni aspekti rodne neravnopravnosti u Srbiji, od polovine 20. veka

Demographic and social aspects of gender inequality in Serbia from second half of 20th century

UNIVERZITET U BEOGRADU EKONOMSKI FAKULTET BEOGRAD ANKICA S. ŠOBOT DEMOGRAFSKI I SOCIJALNI ASPEKTI RODNE NERAVNOPRAVNOSTI U SRBIJI, OD POLOVINE 20. VEKA DOKTORSKA DISERTACIJA BEOGRAD, 2012. I Mentor: prof. dr Biljana Radivojević, Ekonomski fakultet Univerziteta u Beogradu, Beograd Članovi komisije: Doktorat demografskih nauka II DEMOGRAFSKI I SOCIJALNI ASPEKTI RODNE NERAVNOPRAVNOSTI U SRBIJI, OD POLOVINE 20. VEKA Apstrakt Mada rodna neravnopravnost više decenija pobuđuje pažnju istraživača, još uvek je relevantno polje istraživanja i aktuelna društvena tema. Krajem dvadesetog veka pojačava se angažovanje različitih političkih subjekata u cilju prevazilaženja rodnog jaza u svim sferama, ali društvena nejednakost žena i muškaraca je složena i duboko strukturalno uronjena. Brojna rodna pitanja su važna i sa stanovišta demografskog razvoja, pa demografija ne sme da zanemari ovaj socijalni fenomen. Najveći deo disertacije čini socio-demografska analiza muškog i ženskog stanovništva Srbije bazirana na relevantnim popisnim podacima. Mlađe sredovečne žene češće od muškaraca su u braku i češće imaju tercijarni nivo obrazovanja, ali one su češće i ekonomski zavisne. Stariji sredovečni muškarci i stari 65 i više godina imaju povoljnije socio- demografske karakteristike. Među starijim ženama značajno je rasprostranjeno udovištvo, nivo obrazovanja je niži u poređenju sa muškarcima i jasno je vidljiva ekonomska zavisnost. U pogledu ekonomske aktivnosti postoje rodne razlike u socio-profesionalnoj strukturi, relevantne za postojeće društvene nejednakosti. Žene i muškarci se razlikuju u bračnom ponašanju i u pogledu ponašanja kada je u pitanju obrazovanje. Međutim, razlike u ekonomskoj aktivnosti ne mogu se ograničiti na efekte ponašanja. Zaposlenost žena predstavlja često razmatranu varijablu odlučivanja o materinstvu i reproduktivnog ponašanja. Suprotno od toga, kreiranje uslova za optimalno usklađivanje porodice i posla u slučaju oba pola nalazi se u osnovi rešavanja pitanja rodne neravnopravnosti. Prema većini pokazatelja uočene su nepovoljnosti ženskog stanovništva centralne Srbije bez Beograda, u odnosu na žene u gradu Beogradu i u Vojvodini. Isto je i sa ženama u ruralnim naseljima u odnosu na one koje žive u gradovima. Stoga, životne situacije i društveni položaj žena zavise od ekonomskih i kulturnih okolnosti svakog od područja, ali ne treba zanemarivati njihov ekonomski, bračni i obrazovni status. Nekoliko indikatora ukazuje na nepogodnosti muške populacije, u poređenju sa ženama. Jedan od njih je očekivano trajanje života, koji produkuje nepovoljne socio-demografske karakteristike ženskog stanovništva. Udeo visoko obrazovanih među mlađe sredovečnim muškarcima manji je ne samo u odnosu na žene, već i u odnosu na starije generacije muškaraca. Uočeni su negativni efekti društvene tranzicije koja se odvijala tokom poslednje decenije 20. veka u pogledu ekonomske aktivnosti oba pola, ali je ipak ženska populacija nešto intenzivnije pogođena. Rodna perspektiva je neophodna pri razumevanju demografske stvarnosti. Rodne razlike je potrebno rasvetljavati i iz ženskog i iz muškog ugla, istražujući različite demografske procese i pojave.

Although gender inequality has drawn researchers’ attention for many decades, it still is a relevant research topic and a current social issue. At the end of 20th century, various political subjects’ engagement is reinforced, aiming to resolve gender gap in all spheres. However, social inequality between women and men is complex and deeply immerged in the social structure. Many gender issues are relevant for the demographic development and demography must not neglect this social phenomenon. The biggest part of this dissertation consists of the social-demographic analysis of male and female population in Serbia, based on the relevant census data. Younger middle-aged women are married and have high level of education more often than men, but they are also dependent more often. There are favorable socio- demographic characteristics of older middle-aged men and male population over 65 years. Among elder women there is a significantly widespread widowhood, the level of education is more disadvantageous compared with men and their economic dependence is distinctly visible. Regarding economic activity, there are gender differences connected with the social-professional stucture relevant to present social inequality. There are differences between women and men regarding marital behavior as well as the education. However, the differences in economic activity are not to be limited to the effects of the conduct. Women`s employment is frequently regarded as a variable to decision-making about motherhoood and the reproductive behavior. In contrast, creating the conditions for optimal reconciliation of family and work requirements for both sexes goes beoyond resolving gender inequality. Majority of indicators witness the disadvantages of Central Serbia’s (Belgrade excluded) female population compared to women in Belgrade and in Vojvodina. The same is true for women in rural areas compared to women living in the cities. Hence, women’s overall standing and social position is dependent on economic and cultural conditions of a particular region, not disregarding their economic, marital and education status. Several indicators show the disadvantages of the male population compared with female. One of the indicators is life expectation, which affects disadvantageous socio-demographic characteristics of female population. The share of highly educated among younger middle-aged men is less not only related to women but also elder men. Negative effects of social transitions during the last decade of 20th century are noticed regarding economic activity of both sexes, but female population has suffered a more significant setback. Gender perspective is indispensable for understanding the demographic reality. Gender differences should be highlighted from both female and male standpoint, while carrying out research of various demographic processes and phenomena.

Uvođenje prostorne dimenzije u proučavanju kolebanja klime u Srbiji u instrumentalnom periodu

Spatial pattern of climate change in Serbia in the instrumental period

Poslednjih godina, u stručnoj literaturi iz oblasti klimatologije sve više je radova u kojima se analizira prostorni raspored temperature vazduha i/ili padavina na određenoj teritoriji. U tom smislu, sve češća je primena GIS-a i, u okviru njih, upotreba metoda interpolacije. Korišćenje GIS-a u klimatologiji pre svega ima primenu u izradi klimatoloških karata, na kojima je prikazan prostorni raspored nekog klimatskog elementa Kako je osnovni cilj teze uvođenje prostorne dimenzije u proučavanje promena klime u Srbiji u instrumentalnom periodu, to je akcenat bio na prostornoj analizi klimatskih elemenata i vrednosti njihovih trendova. Razmatran je prostorni raspored padavina, temperature vazduha, insolacije, oblačnosti i relativne vlažnosti vazduha u Srbiji u periodu od 1949. do 2010. godine. Analiziran je raspored trenda padavina i temperature vazduha u Srbiji na godišnjem, mesečnom i sezonskom nivou, prostorni raspored trendova uz pomoć tematskih mapa napravljenih primenom web kartiranja. U cilju detaljnije analize režima i njegove nesigurnosti padavina izvršen je analiza dnevnih padavina po kišnim epizodama, njihovim karakteristikama i uticaju na godišnju sumu padavina. Rezultati trenda padavina ne pokazuju statističku značajnost, kao i prostornu koherentnost. Uočena je, međutim, veoma blaga tendencija ka snižavanju padavina na sezonskom nivou, tokom zime i proleća, kao i ka povećanju tokom jeseni. Značajan porast temperature vazduha prisutan je na većini analiziranih stanica tokom poslednje dve decenije. Rezultati dobijeni za Srbiju u skladu sa onim za Evropu. Na mnogim stanicama u Srbiji uočen je trend otopljavanja počev od kraja 1970-ih godina. Negativan trend karakterističan je za insolaciju, oblačnost i relativnu vlažnost vazduha. 6 Rezultati istraživanja generalno ne ukazuju na značajnu promenu klime na teritoriji Srbije, ali ističu značajne razlike u prostornom rasporedu trendova.

Recently, there are many papers analyzing the spatial pattern of air temperature and / or precipitation over the particular area. In this sense, there is very often use of GIS tools and interpolation methods. The use of GIS in climatology is primarily used in climatological maps, depicting the spatial distribution of certain climatic elements. Since the main objective of the thesis is introduction of the spatial approach in the study of climate change in Serbia in the instrumental period, the focus was on the spatial analysis of climatic elements (rainfall, temperature, solar radiation, cloud cover and humidity) and their trends in Serbia in the period 1949-2010. Precipitation and air temperature trend an annual, monthly and seasonal level has been analyzed, applying thematic maps made using web mapping tools. In order to get insight the analysis of the rainfall regime and its uncertainty, rain-spell analysis was performed. General results are showing absence of statistically significant rainfall trends and their spatial coherence. There is, however, slight tendency towards drier conditions during the winter and spring, and the opposite one in the autumn. A significant increase in temperature is detected during the last two decades. The results obtained for Serbia are in line with those obtained for Europe. At many stations in Serbia, there has been a warming trend from 1970s. The negative trend is also calculated for number of sunshine hours, cloud cover and relative humidity. Results generally suggest very weak trends all over the Serbia at annual scale, but show significant spatial patterns.

Integralni koncept zaštite sliva i hidrografske mreže u cilju pretvaranja retenzija u akumulacije za vodosnabdevanje

An Integrated concept of the river basin and hydrographic network protection in the process of transformation the retentions in reservoirs for water supply

Osnovni cilj ove teze je ispitivanje mogućnosti pretvaranja retenzija u akumulacije, na bazi izučavanja slivnog područja, hidrografske mreže, analiza rečne vode i prognoze promena kvaliteta ujezerene vode. Vodosnabdevanje iz otvorenog rečnog toka je promenljivo u pogledu količina i kvaliteta vode. Za racionalno korišćenje površinskih voda, potrebno je izgraditi odgovarajuće akumulacije. Izgradnjom brane i formiranjem akumulacije dolazi do promene dinamike, bilansa i kvaliteta vode, što utiče na stabilnije prilike za vodosnabdevanje. Negativni uticaji izgradnje brane ogledaju se u narušavanju ambijentalnih karakteristika oblasti, poremećaju biljnog i životinjskog sveta, promeni strukture i funkcije vodenog ekosistema i ekosistema obodnog područja. Usled promene tipa ekosistema, tokom vremena, dodatno može doći do pogoršanja kvaliteta vode, ubrzanog „starenja“ vodnog tela i intenzivnog procesa eutrofikacije. Stepen eutrofikacije i intenzitet „starenja“ akumulacije može se predvideti upotrebom matematičkih modela. Negativne posledice pregrađivanja vodotoka, inženjerskim i biološkim merama mogu se ublažiti. Integralni koncept zaštite i korišćenja voda podrazumeva precizno planiranje i realizaciju administrativnih, tehničkih i socioekonomskih mera, istražnih radova, merenja, izrade projektne dokumentacije, eksproprijacije zemljišta, uređenja i zaštite sliva. Ove mere su u skladu sa Okvirnom Direktivom o vodama EU (Directive 2000/60/EC) u domenu dugoročne zaštite od degradacije i zagađenja i upravljanja kvalitetom resursa planinskog sliva na principima održivog razvoja. Glavni cilj Direktive je obezbeđenje dobrog hidrološkog, hemijskog i ekološkog statusa svih prirodnih voda do 2015. godine. Prognozu kvaliteta vode u budućem veštačkom jezeru i integralne mere zaštite slivnog područja, moguće je uraditi modeliranjem na osnovu baze podataka o kvalitetu rečne vode i karakteristika slivnog područja. Najčešće se koriste fizičko-geografski, klimatski, geološki, pedološki, hidrološko-hidraulički, fitocenološki, podaci o načinu korišćenja zemljišta, proticaju i kvalitetu vodotoka na kome se planira izgradnja akumulacije. Za modeliranje su, osim navedenih parametara, neophodne i geometrijske karakteristike buduće akumulacije. Izrada baze podataka za potrebe izgradnje akumulacije za vodosnabdevanje zahteva višego- dišnje multidisciplinarne istražne radove, kompleksne analize i obradu podataka o slivnom području, produkciji i transportu nanosa, proticaju i kvalitetu rečne vode. Za proračune i modeliranje u ovom radu je korišćena baza podataka eksperimentalnog sliva reke Velika Dičina, koja se od 1984. godine koristi za vodosnabdevanje Gornjeg Milanovca. Voda se zahvata iz otvorenog rečnog toka ispod postojeće retenzione pregrade, čija je rekonstrukcija (izgradnja brane Banjani) planirana u narednom periodu. Slivno područje pripada kategoriji veoma slabe erozivnosti površinskog tipa, sa koeficijentom erozije Zsr=0,17. Površina sliva do profila postojeće retenzije iznosi 22,5 km2, a srednji godišnji proticaj 274 l/s. Za eksploataciju i upravljanje sistemom je važno da se još u fazi planiranja sagledaju i prognoziraju dinamički procesi koji će se odvijati u akumulacijama, u vidu promena abiotičkih i biotičkih stanja akvatorija – ekološka stabilnost. U ovom radu je korišćen matematički model UNEP-PAMOLARE 3, koji simulira sve značajne pokazatelje kvaliteta vode, a posebno eutrofikaciju (Jorgensen S., et al. 2003). To je model sa dva sloja, srednje složenosti (a medium complex 2-layer model). Dva sloja predstavljaju epilimnion (gornji sloj) i hipolimnion (donji sloj) jezera koje je termički stratifikovano u vertikalnom pravcu, a razmena materije između njih se odvija kroz termoklinu difuzionim transportom. Modeliranje je urađeno za proticaje izmerene 2007. godine i geometrijske karakteristike predviđene akumulacije. Zapremina akumulacije do kote krune preliva iznosi 2,93x106 m3, dužina jezera 1850 m, prosečna širina 145 m i prosečna dubina 13,5 m. Rezultati modela prikazani su grafički, kao sezonske promene osnovnih eutrofikacionih pokazatelja: rastvorenog kiseonika, hlorofila-a (u diatomama), ukupnog azota i ukupnog fosfora. Uočljivo je smanjenje koncentracije ukupnog azota (sa 1,8 mg N/l u martu na 0,2 mg N/l u julu) i ukupnog fosfora (sa 0,020 na 0,001 mg P/l) u epilimnionu u toku leta, kada ove nutrijente konzumira fitoplankton u periodu intenzivnog rasta. Koncentracije rastvorenog kiseonika vode u jezeru na početku godine, pri niskim temperaturama vode, su bliske saturisanim. U toku leta, usled rasta temperature vode, opada koncentracija kiseonika u oba sloja. U epilimnionu koncentracija kiseonika pada sa 15 na 7 mg O2/l, a u hipolimnionu pad je još izraženiji, sa 15 na 3 mg O2/l. Termoklina, u ovom periodu, otežava prodor kiseonika iz epilimniona i stvaraju se uslovi za anaerobno raspadanje organske materije. Početkom jeseni dolazi do obnavljanja rezervi rastvorenog kiseonika zbog hlađenja vode i njenog mešanja usled dejstva vetra. Rezultate modeliranja kvaliteta vode u budućoj akumulaciji Banjani treba prihvatiti sa izvesnom rezervom, obzirom da su određeni parametri usvojeni na bazi iskustava stečenih u analizama kvaliteta vode na sličnim akumulacijama. Model je moguće kalibrisati samo na osnovu neke postojeće, a jako slične akumulacije. Sličnost se definiše na osnovu kriterijuma vezanih za: nadmorsku visinu i karakteristike reljefa područja; karakteristike erozije u slivu akumulacije; površinu, zapreminu, dužinu, širinu i dubinu jezera; parametre kvaliteta vode i sedimenta; podatke o zagađenju vodotoka, itd. Stepen trofije akumulacije može se predvideti na osnovu analize procesa u sistemima koji su, prema navedenim karakteristikama, slični budućoj akumulaciji. Analize trofičkog statusa akumulacija u Srbiji i Sloveniji pokazale su da nema oligotrofnih akumulacija. Eutrofnih akumulacija ima više od mezotrofnih. Ekološki potencijal većine akumulacija nije zadovoljavajući. Akumulacije Grošnica u Srbiji i Klivnik u Sloveniji su veoma slične akumulaciji Banjani. Obe su mezotrofne sa pojedinim parametrima koji povremeno prelaze granicu između mezotrofnog i eutrofnog stepena. Nisu uočljivi tragovi „starenja“ jezera, koja i nakon višedecenijske eksploatacije imaju stabilne ekosisteme. Trofički status buduće akumulacije Banjani, na osnovu rezultata modeliranja i podataka za akumulacije Grošnica (TSI = 44) i Klivnik (ekološko stanje „umereno“), očekuje se u granicama mezotrofije, bez pojave anaerobnih uslova i u najdubljim delovima akumulacije. Ovakvo stanje rezultat je dobrog kvaliteta vode u reci Velika Dičina, koji se prema većem broju parametara nalazi u I klasi, a određen broj parametara prelazi u više klase kvaliteta. Pored toga, projektovana akumulacija Banjani je kanjonskog tipa, relativno duboka i bez većih plitkih zona u kojima bi moglo doći do bržeg procesa eutroflkacije. Kvalitet vode u jezeru može se održavati u dobrom stanju, selektivnim vodozahvatom i korišćenjem pokazatelja monitoringa kvaliteta vode u upravljanju vodoprivrednim sistemom. Pre izgradnje brane i punjenja jezera neophodno je uraditi protiverozionu zaštitu sliva, sanitarno uređenje prostora do kote maksimalnog uspora i uspostavljanje administrativnih zabrana i zona sanitarne zaštite akumulacije. Zaštita zemljišta od erozije zasniva se na primeni koncepta integralnih melioracija, koje sadrže biotehničke i tehničke radove. Biotehnički radovi obuhvataju pošumljavanje i melioracije degradiranih površina, podizanje ilofilterskih sistema i terasa za usporavanje površinskog oticaja i spiranja zemljišta. Tehnički radovi se odnose na izgradnju poprečnih pregrada, pragova i pojaseva za stabilizaciju korita i zadržavanje nanosa. Težište antierozionih mera je na biotehničkim radovima i uvećanju pošumljenosti sliva, jer se pored zaštitne funkcije stvaruju uslovi za očuvanje biološke raznovrsnosti. Efekti pošumljavanja i uvećanja površina pod vegetacijom se ogledaju na stvaranju povoljnijih hidroloških uslova u slivu, razvoju zemljišta i kapaciteta infiltracije, ublažavanju procesa erozije, smanjenju maksimalnog proticaja i zapremine poplavnog talasa, smanjenju taloženja nanosa u akumulaciji i rizika od bujičnih poplava (Ristić R., et al., 2013). Antierozione radove na slivu treba početi 10-15 godina pre formiranja akumulacije. Pošumljavanje goleti može dati pozitivne efekte osam godina posle sadnje, melioracije degradiranih livadsko-pašnjačkih površina, setvom travnih smeša, posle dve godine. Tehničke radove u hidrografskoj mreži treba završiti godinu dana pre početka formiranja akumulacije, zbog stabilnosti korita, smanjenja transporta nanosa i zasipanja akumulacije.

The main objective of this dissertation is to examine the possibility of converting retention basins to reservoirs, on the basis of the study of the catchment area, hydrographic network, and forecasts of river water quality changes of the accumulated water. Water supply from running waters is variable in terms of quantity and quality of the resource. Therefore, for the effective use of surface water, it is necessary to build appropriate reservoirs. The construction of the dam and reservoir formation results in a change of the dynamics, balance and quality of water, which makes the conditions for water supply more stable. Negative impacts of dam construction are reflected in disturbance of environmental conditions of the area, disruption of longitudinal connectivity, and change of the structure and function of aquatic and riparian ecosystems etc.. Additionally, the deterioration of water quality and eutrophication can occur, as well as intensive „aging“ of the reservoir. The degree of eutrophication and the rate of the “aging” of accumulations can be predicted using mathematical simulation models. Furthermore, the intensity of the negative consequences of watercourses partitioning can be decreased using mitigation (engineering and biological) measures. An integrated concept of water protection and use involves precise planning and implementation of administrative, technical and socio-economic measures, research works, measurements, preparation of project documentation, land acquisition, and protection of the catchment area. These measures should be consistent with the EU Water Framework Directive (WFD) in the domain of long-term protection from degradation and pollution, in order to manage quality resources of mountainous river basins along with principles of sustainable development. The main objective of the WFD is to provide a good status of all water bodiesby the year 2015. Forecasting of water quality in the future reservoir and design of integrated measures to protect the catchment area can be fulfilled by modeling. The most commonly used databases are: physical-geographical, climatic, geologic, pedological, hydrologic-hydraulic, phytocenological, information on land use, water flows and quality of the stream relating to the location planned for the construction of reservoirs. To use established mathematical simulation models, besides given parameters, certain geometric characteristics of projected reservoirs are necessary. The design and construction of reservoirs for water supply demands many years of multidisciplinary investigations, which comprise data processing of the catchment area, generation and transport of sediment, flow and water quality. In this study, calculations and modeling were based on the data collected during long term study of the Velika Dicina River. This river has supplied water to the City of Gornji Milanovac since 1984. The water abstraction take place below the retention of the existing bulkhead, which reconstruction (dam construction Banjani) is planned in the future. The catchment area belongs to the category of very low surface erosion (top layer), the coefficient of erosion being Zsr = 0.17. The catchment area (to the profile of the existing retention) is 22.5 km2, and average yearly flow is 274 l/s. It is important to effectively manage this water abstraction system. All dynamic processes that will take place in this reservoir, including changes in abiotic and biotic conditions, should be foreseen during the planning stage. In this dissertation, the mathematical model PAMOLARE UNEP-3 was used, which simulates significant indicators of water quality with a focus on eutrophication. This model has two layers of medium complexity (a 2- complex medium layer model) - the epilimnion (upper layer) and hypolimnion (lower layer) of the lake that is thermally stratified in the vertical direction and the exchange of substance between them takes place by diffusion through the thermocline transport. The modeling was done using flow data for 2007, as well as geometric characteristics of the planned accumulations. The accumulation volume, up to the level of the crown overflowing is 2.93 x 106 m3. The length of the lake is 1850 m, the average width is 145 m and the average depth is 13.5 m. Model results are shown graphically, as seasonal changes in eutrophication basic indicators: dissolved oxygen, chlorophyll-a (in diatoms), total nitrogen and total phosphorus. It is very noticable decrease the concentration of total nitrogen (0.2 to 1.8 mg N/l) and total phosphorus (0.001 to 0.020 mg P/l) in the epilimnion during the summer when the phytoplankton consumes nutrients during the period of its intensive growth. Concentrations of dissolved oxygen in both layers are at the beginning of the calendar year close to saturated, because the water is homogeneously mixed in the lake. During the summer, due to rising water temperatures, concentration of oxygen decrease (3-15 mg O2/l) in both layers, especially in the hypolimnion where conditions are created for the decomposition of organic matter becouse thermocline hinders the penetration of oxygen from the epilimnion. In early autumn, there is a renewal reserve of dissolved oxygen due to cooling water and its mixing by the wind. The results of water quality modeling for the future reservoir Banjani should be taken with some caution, considering that certain parameters, relations and functions are assumed, drawing on the results of the analyses of water quality in similar reservoirs. The model can be calibrated on the basis of an existingreservoirs that are similar in regard to overall characteristics. The similarity is defined based on criteria related to: altitude and areas relief characteristics, characteristics of erosion in the basin of the reservoir, surface, volume, length, width and depth of the lake, water and sediment quality parameters; data on watercourses pollution, etc. The trophic levels can be predicted on the basis of what take place in systems similar to the future reservoir, according to the above characteristics. The analyses of the trophic status of reservoirs in Serbia and Slovenia have shown that there are no oligotrophic reservoirs. There are more eutrophic reservoirs than mesotrophic. The ecological potential of the most reservoirs in both countries is not satisfactory. The Grošnica and Klivnik are similar reservoirs in compare with the Banjani. Both reservoirs are mesotrophic, but some parameters occasionally cross the limit between mesotrophic and eutrophic. They are not visible signs of „aging“ of the lake, and ecosystem is stable in spite of decades of exploitation. Trophic status of future reservoir Banjani, based on modeling results and data for Grošnica (TSI = 44) and Klivnik (ecological status „moderate“), it is expected to be within the mesotrophic limits, without the appearance of anaerobic conditions in the deepest parts of the reservoir. This is due to relatively good water quality in the river Velika Dicina, classified as Class I, according to value of numerous parameters. Some parameters exceed the upper-class quality. In addition, the projected accumulation Banjani is a canyon-type, relatively deep and with no significant shallow areas with conditions suitable for faster eutrophication process. Good water quality in the lake can be maintained by good managing of water supply systems primarily using selective water-intake and monitoring of all indicators of water quality. Before the construction of the dam and filling with water it is necessary to do the erosion control basin protection, sanitary and landscaping below the level of maximum deceleration and the establishment of administrative restrictions and sanitary protection zone of accumulations. Protection of soil erosion based on the application of the concept of integrated land reclamation, which include biotechnology and technical works. Biotechnical works include afforestation and reclamation of degraded areas, raising ilofilters systems and terraces to slow surface runoff and soil erosion. Technical works related to the construction of cross sections, sills and belt to stabilize the bed and sediment retention. Anti-erosion measures are focused on biotechnical works and increasing forest coverage of the basin that create conditions, in addition to the protective function, to preserve and enhance biodiversity. The effects of afforestation and increasing the area under vegetation reflect on the creation of favorable hydrological conditions in the basin, development of land and the infiltration capacity, easing the process of erosion, reducing the maximum volume flow and flood wave, reducing sediment deposition in the reservoir and the risk of extensive floods (R. Ristic, et al., 2013). Erosion protection in the basin should begin 10-15 years before the forming of accumulations. Afforestation can yield positive effects after eight years after planting, but reclamation of degraded meadow-pastures, grass seeding mixtures, after two years. Engineering works in the hydrographic network should be completed one year before the reservoir formation because it affects the stability of the riverbed, reduce sediment transport and reservoir siltation.

Efekti privatizacije preduzeća od strateškog interesa u privredi Srbije

Effects of privatization of companies of strategic importance for Serbian economy

Privatizacija označava transfer sredstava koja su nekada bila u državnom i društvenom vlasništvu u ruke privatnog sektora. Državna i društvena vlasnička struktura bila je uobičajena i imala je daleko veći broj oblika u bivšim socijalističkim zemljama nego što je to slučaj sa zemljama zapada. Ciljevi privatizacije su raznovrsni i brojni, tako da se razlikuju pre svega ekonomski, politički i socijalni, a zatim ciljevi na makro i mikro nivou. Novi Zakon o privatizaciji usvojila je Skupština Srbije 2001. godine i time postavila temelj svoje strategije svojinskih promena. U radu se govori o konceptima privatizacije u skladu sa zakonom, tenderskoj prodaji i postupcima restrukturiranja, kao modelima za privatizaciju preduzeća od strateškog interesa u Republici Srbiji. Efekti privatizacije su sagledani u širem i užem smislu, kako uticaja na opšti privredni razvoj, tako i posledica posmatranih na grupi privatizovanih preduzeća od strateškog interesa u domenu njihove operativnosti i realizacije, socijalnog aspekta (zaposlenih) i modernizacije (priliv investicija). Jedan od ciljeva rada je da kroz sveobuhvatno sagledavanje dosadašnjih rezultata privatizacije preduzeća od strateškog interesa i uticaja istih na strukturne promene, da smernice za nastavak i odabir daljih aktivnosti u funkciji uspešnog završetka privatizacionog procesa u Republici Srbiji. Poseban osvrt u radu dat je na privatizaciji javnih preduzeća, koja je tek u inicijalnoj fazi u Srbiji, uz prethodno sagledavanje sličnih primera iz drugih zemalja u tranziciji i prakse razvijenih zemalja zapada.

Privatization determines transfer of funds, that were once state-owned or socially-owned, into the private ownership. State- and socially-owned company structures used to be more common and more diverse in former socialist countries than it was the case in western countries. Privatization targets are various and numerous, differing primarily in terms of economic, political and social aspects, but also on macro and micro levels. New Privatization Law was adopted by the Assembly of Serbia in 2001 which thus laid foundations for change strategy of companies' ownership structure. This thesis is about privatization concepts which are in accordance with the law, tender sale and restructuring procedures, and are used as models for company privatization of strategic importance for the Republic of Serbia. Privatization effects are put into broad and narrow prospective of both impact on the overall economic development and the consequences observed on a group of privatized companies of strategic importance within their effectiveness and realization, social aspect (employees) and modernization (investment inflow). One of the above mentioned targets is to provide directions for continuation and selection of further activities regarding successful completion of the privatization process in the Republic Serbia, and that by means of comprehensive observation of the existing results of the privatization of companies of strategic importance and their impact on the structural changes. This thesis puts special emphasis on privatization of public companies, the process which is in initial phase in Serbia, with previous consideration of similar examples from other countries in transition and best practice of the developed western countries.

Razmeštaj stanovništva Srbije u kontekstu teorija o populacionom optimumu

Spatial distribution of population in Serbia considering optimum population theories

Razmeštaj stanovništva odražava celovitost prirodnih, društvenih, ekonomskih i istorijskih činilaca geoprostora, relevantnih kako za fundamentalna, tako i za aplikativna istraživanja. Složenu prostornu strukturu savremenog razmeštaja populacije u svetu, kao i u Srbiji, tokom istorije su determinisale ljudske migracije, složenog obima i determinanti. U naučnim raspravama u dužem vremenskom periodu stariji modeli razmeštaja su uglavnom tretirali disperziju, a noviji modeli, pre svega od 70- ih godina XX veka, polarizaciju, odnosno grupisanje stanovništva kroz prostornu koncentraciju. Ova pitanja su srž geografskog pristupa stanju i razvoju populacionih sistema, koji se sagledava kroz prostorno-analitički pristup. Cilj je prevashodno ispitivanje prostornih aspekata populacionih fenomena kroz osobine razmeštaja, oblika prostornih struktura, veza i odnosa elemenata demografskih i ostalih prostornih sistema kao dinamičnih i vremenski promenljivih kategorija. Razmeštaj je rezultat promena do kojih se došlo u prethodnim i prelaznim stanjima demografskog i ukupnog razvoja. Razvoj analitičko-prostornog pristupa u populacionoj nauci u korelaciji je sa korišćenjem savremenih kvantitativnih metoda i tehnika istraživanja, jer matematičke i statističke metode olakšavaju razmatranje toka i determinanti populacionih fenomena. Optimalan broj stanovnika se najčešće razmatra u odnosu na kompleks veza između resursa, prostora, nivoa tehnološkog i poljoprivrednog razvoja, migracionih kretanja, kao i sve značajnijeg odnosa između starog i mladog stanovništva na određenoj teritoriji. Jedno od osnovnih pitanja jeste gde je ravnoteža (ili kompromis) između kvantiteta stanovništva i kvaliteta života? Najčešći odgovor je da se ona može naći u razmeštaju stanovništva, jer se najoptimalnija distribucija stanovništva danas nameće kao apsolutna potreba. 5 Cilj istraživanja u ovoj doktorskoj disertaciji je sagledavanje razvoja teorije populacionog optimuma u dužem istorijskom periodu, da bi se definisao pravac u savremenim teorijskim raspravama, kao i da se dođe do osnove teorijskog modela koji je mogao biti primenjen na statističkom empirijskom materijalu za Srbiju. To se postiglo praćenjem stavova o optimalnom broju stanovnika od najstarijih vremena do danas, uz njihovo apstrahovanje i naglašavanje najznačajnijih modela, kako bi se bolje izvršila njihova evaluacija. U svetu postoji brojna literatura koja tretira teorijske aspekte populacionog optimuma, održano je mnogo naučnih skupova na tu temu, a poslednjih decenija osnovan je i značajan broj organizacija koje izučavaju ovu problematiku. Urađen je i veliki broj empirijskih analiza kako na globalnom, tako i na nacionalnom nivou, što je u vezi sa intenziviranjem istraživanja ovog fenomena naročito od 70-ih godina XX veka, kada dolazi do reafirmacije teorije populacionog optimuma. U Srbiji je literatura koja tretira problematiku populacionog optimuma skromna, a ovim pitanjem su se pored demografa bavili i stručnjaci drugih naučnih orjantacija. U ovoj disertaciji analiza razmeštaja i prerazmeštaja stanovništva je izvršena na različitim nivoima teritorijalne strukture Srbije po kojima su demografski procesi i njima stvoreni populacioni potencijali neravnomerno prostorno distribuirani. Korišćeni statistički materijal se odnosi na period 1961-2011. godine, sa posebnim težištem na podacima popisa stanovništva 2002. godine, a u cilju analize razmeštaja po svim elementima demografskog sistema i utvrđivanja dostignutog stepena koncentracije populacije na prostoru Srbije na početku XXI veka. Stanje i razvoj demografskih sistema u Srbiji u kontekstu optimalnog rasta, strukturnog balansa i prostornog razmeštaja, sagledano je pomoću izabranih mera, metoda i tehnika razmeštaja, a na osnovu empirijske građe vitalne i popisne statistike prevashodno u periodu nakon Drugog svetskog rata. Analizirani su trendovi u razmeštaju stanovništva Srbije preko: popululacione dinamike, populacione veličine opština, opštih i 6 specifičnih gustina naseljenosti, koeficijenta kretanja; centrografskih i mera disperzije; mera, indeksa i tipova koncentracije. Većina analiziranih mera i pokazatelja dostignutog nivoa koncentracije, potvrđuju odmaklost ovog procesa u Srbiji do početka XXI veka. Presek po različitim demografskim obeležjima za popisnu 2002. godinu pokazuje najveću koncentraciju u etnodemografskoj sferi, tj. Albanci, Vlasi, Muslimani i Bošnjaci naseljavaju kompaktne teritorije Srbije. Evidentna je i visoka koncentracija stanovništva gradskih naselja, opštinskih centara, stanovništva sa završenom srednjom, višom školom i fakultetom i stanovništva koje obavlja zanimanje u sekundarnom i kvartarnom sektoru delatnosti. Stanovništvo po svim ostalim posmatranim obeležjima je ravnomernije raspoređeno u prostoru Srbije, a to se posebno odnosi na poljoprivredno stanovništvo, stanovništvo u seoskim naseljima, stanovništvo koje obavlja zanimanje u primarnom sektoru delatnosti i lica bez školske spreme. Navedene razlike u dostignutom nivou koncentracije po pojedinim demografskim obeležjima u Srbiji u korelaciji su sa istorijskim razvojem naseljenosti, tranzicijom agrarnog u industrijsko društvo i procesom urbanizacije Srbije u poslednjih pola veka. Preko određenih sinteznih pokazatelja teritorijalnih demografskih sistema ukazano je na pogodnosti, ali i na limitirajuće faktore koje dostignuti nivo i stepen koncentracije prema kvantitativnim i kvalitativnim obeležjima stanovništva ima danas, a što je rezultat vremenski i teritorijalno specifično utemeljenih determinanti demografskih procesa na makro, mezo i mikro nivou Srbije. Sagledavanje savremenog demografskog potencijala pokazalo je da su na većem delu teritorije Centralne Srbije i Vojvodine ugroženi populacioni resursi, izuzev u gradovima različitog funkcionalnog nivoa. Ohrabruje činjenica da su populacioni potencijali malih gradova (do 20.000 stanovnika) još uvek očuvani, te mogu biti polovi demografskog preobražaja depopulacionih prostora u budućnosti. Indeks humanog razvoja (HDI) pokazuje da treba poboljšati komponenete koje se odnose na obrazovanje i očekivano trajanje života. Populacioni potencijali u Centralnoj Srbiji i Vojvodini mogu se u budućnosti obnoviti ulaganjem u obrazovanje stanovništva, stručno usavršavanje, u zdravstveni sistem, a sve u cilju ravnomernijeg prostornog 7 razmeštaja stanovništva. Tipovi kretanja ilustruju svu složenost i ugroženost demografskog razvitka na znatnom delu teritorije Centralne Srbije i Vojvodine (seoska naselja, brdsko-planinski prostori, pogranični prostori). Zato se mora studiozno pristupiti pravcima rešavanja pitanja i problema prostorno – demografske polarizacije Srbije, sa aspekta kvantitativnih i kvalitativnih odlika populacionih potencijala. To znači prerazmeštaj ukupnog i gradskog stanovništva, ostvarenje rehabilitacije prirodne reprodukcije stanovništva, preusmeravanje migracionih tokova i dostizanje demografskog balansa u strukturnim obeležjima stanovništva na svim regionalnim nivoima. Ova pitanja zahtevaju poseban pristup u politici razmeštaja i prerazmeštaja stanovništva Srbije u XXI veku kroz mere populacione, ali i ostalih razvojnih politika. Ova pitanja prepoznata su i u usvojenoj zakonskoj regulativi u Srbiji. Međutim ostaje i dalje potreba za širim naučnim razmatranjima na temu poželjnih stopa rasta stanovništva i optimalnih gustina naseljenosti uz određena, za demografski i ukupni razvoj važna kvalitativna (strukturna) svojstva stanovništva. To se generalno podvodi pod pojam populacionog optimuma, sagledanog u domenu demografije kroz populacionu politiku.

Distribution of the population reflects the integrity of the natural, social, economic and historical factors of the geospace, relevant both for fundamental and for applied researches. Complex spatial structure of the contemporary distribution of population in the world, and in Serbia as well, during history were specified by human migrations of complex scope and determinants. In the scientific debates over the long term, the older models of distribution generally treated dispersion, and the newer models, mainly from the 70s of XX century, polarization, that is, clustering of the population through spatial concentration. These questions are the core of geographic access to the condition and development of population systems, that can be viewed through spatial-analytical approach. The aim is primarily a test of spatial aspects of population phenomena through distribution characteristics, forms of spatial structures, connections and relationships between demographic elements and other spatial systems as dynamic and temporally variable categories. Distribution is a result of the changes that have occurred in the past and transitional conditions of demographic and overall development. Development of the spatial-analytical approach in population science is correlated with the use of modern quantitative methods and technical researches, as mathematical and statistical methods facilitate consideration of the flow and the determinants of population phenomena. The optimal population number is most often discussed in relation to the complex relationship between resources, space, level of technological and agricultural development, migrations, as well as any significant relationship between the old and the young population in a given territory. One of the main questions is where is the balance (or compromise) between the quantity and the quality of life? The most common answer is that it can be found in the distribution of population, as the most optimal distribution of population today imposes as an absolute necessity. The aim of research in this PhD thesis is to assess the development of the theory of population optimum over a longer period of history, to define the direction in 9 contemporary theoretical debates, as well as to get to the base of the theoretical model that could be applied to the statistical empirical material for Serbia. This has been achieved by monitoring the attitudes of the optimal population number from ancient times to the present, with its abstraction and emphasis on the most significant models in order to better perform their evaluation. In the world there is a numerous literature that treats the theoretical aspects of the population optimum, many conferences on the subject were held, and in recent decades a significant number of organizations studying this issue had been also established. A large number of empirical analyses on both the global and the national level have been done, which is associated with the intensification of research of this phenomenon especially since the 70-ies of XX century, when there was a reaffirmation of the population optimum theory. In Serbia, the literature that addresses the issue of the population optimum is modest, and the issue, in addition to demographers, was dealt by experts of other scientific orientations as well. In this dissertation, an analysis of the population distribution and redistribution was performed at different levels of the territorial structure of Serbia by which demographic processes and population potentials created by them were unevenly spatially distributed. Used statistical material covers the period from 1961 to 2011, with a particular focus on the Census 2002 , and in order to analyse the distribution by all elements of the demographic system and determination of the achieved degree of population concentration in Serbia at the beginning of the XXI century. Condition and development of the demographic systems in Serbia in the context of optimal growth, structural balance and spatial distribution, was examined by the use of selected measures, methods and techniques of distribution, based on the empirical data of vital and census statistics primarily in the period after the Second World War. We analysed the trends in the population distribution of Serbia through the following: population dynamics, population size of the municipalities, general and specific density, coefficient of movement; centrographic and measures of dispersion; measures, indices and types of concentration. Most of the analysed measures and indicators of the achieved level of concentration confirm the progress of this process in Serbia until the beginning of the XXI century. Breakdown by various demographic characteristics of the 10 year 2002 Census shows the highest concentration in the ethnodemographic sphere, i.e. Albanians, Vlachs, Muslims and Bosnians inhabiting the compact territories of Serbia. Also evident is the high concentration of population in the urban areas, municipal centers of population with secondary, college and university degree, and the population working in the secondary and quaternary sector of activity. Population by all other observed characteristics is more evenly distributed across the area of Serbia, and this is especially true for the agricultural population, the population in rural areas, population working in the primary sector of activity and people without any qualifications. These differences in the achieved level of concentration in certain demographic characteristics in Serbia are correlated with the historical development of population, transition from an agrarian into industrial society and process of urbanization of Serbia in the last half century. By the use of certain synthesis indicators of the territorial demographic systems it has been pointed to the benefits, but also the limiting factors which achieved level and degree of concentration according to the quantitative and qualitative characteristics of the population has today, and which is a result of a temporally and territorially specifically established determinants of the demographic processes at macro, meso and micro level of Serbia. Consideration of the contemporary demographic potential showed that the greater part of the territory of Central Serbia and Vojvodina the population resources were vulnerable, except in the cities of different functional levels. Encouragingly, the population potentials of small towns (up to 20,000 inhabitants) are still preserved and can be poles of the demographic transformation of depopulated areas in the future. The Human Development Index (HDI) shows that the components that relate to education and life expectancy should be improved. Population potentials in Central Serbia and Vojvodina can be renewed in the future by investing in the education of the population, professional development, health system, and all that in the aim of more even spatial distribution of the population. Types of movement illustrate the complexity and vulnerability of demographic development on a substantial part of the territory of Central Serbia and Vojvodina (villages, mountainous areas, border areas). Therefore, it must be studiously access to the directions of resolving the issues and problems of the spatial-demographic polarization of Serbia, in terms of quantitative and qualitative characteristics of the population potentials. That means a redistribution of 11 the total and urban population, realization of rehabilitation of the population natural reproduction, redirection of migration flows and achievement of demographic balance in the structural characteristics of the population at all regional levels. These issues require a special approach to the policy of distribution and redistribution of the Serbian population in the XXI century, through measures of population, but also other development policies. These issues have been recognized as well in the adopted legislation of Serbia. However remains a need for a broader scientific considerations on the desirable rate of population growth and optimal density with the determined, for demographic and overall development of important qualitative (structural) characteristics of the population. It is generally subsumed under the concept of the population optimum, presented in the field of demography through the population policy.

Strategijski brend menadžment kao faktor konkurentnosti kompanija

Strategic brand management as the factor of company competitiveness

Intenzivna konkurencija na tržištu i promenljivi uslovi poslovanja navode kompanije da kontinuirano tragaju za novim izvorima konkurentne prednosti. Globalizacija tržišta ujedinila je potrošače u zahtevima koje postavljaju pred kompanije i doprinela je razvoju novih marketing strategija koje omogućavaju porast satisfakcije i lojalnosti potrošača prema brendu, direktno implicirajući i poboljšanje finansijskih perfomansi u poslovanju. Kreiranje i razvoj brenda predstavlja dugoročnu investiciju kompanije. U doktorskoj disertaciji pokušali smo da ukažemo da primena koncepta brend menadžmenta doprinosi celokupnom učinku brenda na tržištu i ukupnim finansijskim rezultatima. Orijentacija prema brendu kompanije jeste polazna determinanta strategijskog brend menadžmenta. U cilju merenja doprinosa SBM-a poslovnim rezultatima sproveli smo empirijsko istraživanje u 300 prvorangiranih kompanija u 2010. godini, prema kriterijumu - obim prometa u 2009. godini. Prikupljeno je 66 upitnika, od toga 63 validna upitnika, na osnovu kojih smo smo izvršili analizu i izneli rezultate. Rezultati su pokazali da je korelacija statistički značajna i pozitivna između inovacije, informacione tehnologije, orijentacije prema brendu, jedinstvenosti brenda, učinka brenda i finansijskih rezultata, dok između brend barijere i finansijskog rezultata postoji negativna korelacija, potpuno opravdano. Poseban predmet analize je poređenje rezultata implementacije brend menadžmenta u domaćim i inostranim kompanijama na teritoriji Republike Srbije, gde signifikantne vrednosti ukazuju na značajnu razliku tretmana strategijskog brend menadžmenta u domaćim i inostranim kompanijama, u korist inostranih kompanija. Ograničenja sprovedenog terenskog istraživanja ne mogu se ignorisati, međutim rezultati se veoma značajni za sagledavanje doprinosa brend menadžmenta u poslovanju kako za naučnu i stručnu javnost, tako i za privredne subjekte.

Intensive competition in the market and changing business conditions make companies continuously search for new sources of competitive advantage. The market globalization has united consumers in setting their requirements before the companies and contributed to development of new marketing strategies which enable the growth of satisfaction and loyalty of consumers toward a brand, directly implying the improvment of financial performances in business. Creation and development of a brand represents a long-term investment of a company. In this doctorial dissertation, we have tried to point out that the implementation of the brand management concept contributes to the brand's market performance and overall financial performance. Orientation towards the company brand is a starting determinant of the strategic brand management. In order to measure the SBM's contribution to business results,we have conducted an empirical research in 300 companies ranked first in 2010, according to the criteria – turnover in 2009. Finaly, 66 questionnaires were collected, out of which 63 valid ones, based on which we conducted an analysis and presented our results. The results have shown that the correlation is statistically significant and positive between innovation, information technology, orientation towards a brand, brand uniqueness, brand performance and financial performance, while there is a negative correlation between the brand barrier and financial performance, fully justified. Special subject of the analysis is the comparison of the results of the implementation of brand management in domestic and foreign companies in the Republic of Serbia, where significant values point out to important difference in strategic brand management treatment in domestic and foreign companies, in the favor of foreign companies. Limitations to the conducted field research cannot be ignored, however, the results are very significant for understanding the contribution of brand management to business, both for scientific and professional public and for businesses.

Vibracije i izbočavanje ploča i ljuski primenom metode dinamičke krutosti

Vibration and buckling of plates and shells using dynamic stiffness method

Metod dinamičke krutosti (MDK) predstavlja alternativu metodu konačnih elemenata (MKE) u analizi vibracija i izbočavanja konstrukcija. Osnovni element u MDK je kontinualni element, odnosno njegova matrica krutosti, koja je formulisana na osnovu tačnog rešenja diferencijalne jednačine problema, pa je samim tim izbegnuta potreba za diskretizacijom domena. Da bi MDK mogao da nađe širu primenu, potrebna je odgovarajuća baza kontinualnih elemenata. U okviru disertacije su po prvi put formulisani kontinualni elementi za analizu vibracija Mindlin-ove pravougaone ploče i segmenta kružne cilindrične ljuske po Donnell-Mushtari-evoj i Flügge-ovoj teoriji. Za rešenje problema slobodnih vibracija korišćen je Gorman-ov metod superpozicije, dok je dinamika matrica krutosti formulisana pomoću metoda projekcije. Takođe, na osnovu rešenja u zatvorenom obliku formulisani su sledeći kontinualni elementi, odnosno odgovarajuće matrice krutosti, za analizu vibracija i izbočavanja: Maurice Lévy-eve ploče po Mindlin-ovoj teoriji, kružne cilindrične ljuske i segmenta kružne cilindrične ljuske sa specijalnim graničnim uslovima po Donnell-Mushtari-evoj i Flügge-ovoj teoriji. Izvedene matrice krutosti su implementirane u za tu svrhu napisani Matlab program za analizu vibracija i izbočavanja sistema ploča i ljuski. Rezultati mnogobrojnih numeričkih primera su upoređeni sa dostupnim rezultatima iz literature, kao i rezultatima MKE, čime je izvršena verifikacija u radu formulisanih kontinualnih elemenata.

Dynamic stiffness method (DSM) is an alternative to the Finite element method (FEM) in the vibration and buckling analysis. The essential element in the DSM is a continuous element and the corresponding stiffness matrix. The stiffness matrix is formulated based on the exact solution of the governing equations. Consequently, the discretization of the domain is minimized. For a wider application of the DSM, a suitable base of the continuous elements is necessary. Within this thesis, the continuous elements and the corresponding dynamic stiffness matrices for vibration analysis of the Mindlin plate and segment of circular cylindrical shells based on the Donnell-Mushtari and Flügge theory are formulated for the first time. Gorman's method of superposition has been used for solution of the free vibrations problem, while the dynamic stiffness matrix is formulated by using the Projection method. In addition, based on the closed-form solutions of the of free vibration and buckling problem, the following continuous elements are formulated: Maurice Lévy plate element based on the Mindlin theory, circular cylindrical shell and segmented circular cylindrical shell with special boundary conditions element based on the Donnell-Mushtari and Flügge theory. The developed stiffness matrices are implemented in the Matlab program for the vibration and buckling analysis of plates and shells assemblies. The results of numerous numerical examples are compared with the available results in the literature, as well as with the results obtained using the FEM , and, in such way, the formulated continuous elements are verified.

Istraživanje svojstva svežeg i očvrslog samozbijajućeg betona sa mineralnim dodacima na bazi industrijskih nusprodukata

Investigation of properties of fresh and hardened self-compacting concrete with mineral additions based on industrial by-products

Beton, kao jedan od najčešće upotrebljavanih materijala u građevinskoj industriji evoluirao je sa razvojem građevinarstva, od početaka primene do današnjih dana. Konvencionalni beton se ugrađuje pomoću vibrirajuće opreme kako bi se u njemu redukovao sadržaj zaostalog vazduha, eliminisala mogućnost pojave kaverni i drugih šupljina na kontaktima sa armaturom i oplatom (takozvani normalno vibrirani beton, Normal Vibrated Concrete – NVC). Na taj način beton postaje kompaktniji, gušći i homogeniji, što je osnov za njegovo prihvatljivo ponašanje u konstrukciji. Tehnološka operacija kompaktiranja tradicionalno igra ključnu ulogu u proizvodnji kvalitetnog betona sa optimalnom čvrstoćom i trajnošću. Razvoj hemijskih dodataka tipa superplastifikatora omogućio je lakše ugrađivanje betona, pošto se malim doziranjem ovakvog hemijskog dodatka mogu smanjiti sile trenja između čvrstih čestica, što za rezultat daje pokretljivije i obradljivije betone (betone tečnijih konzistencija) koje je lakše ugraditi, uz zadržavanje iste količine vode. Ekstrapolacijom koncepta upotrebe superplastifikatora u pravcu dobijanja betona tečnijih konzistencija došlo se do koncepta samozbijajućeg betona (Self-compacting Concrete - skraćeno SCC). Samozbijajući beton se može definisati kao beton, koji će bez primene mehaničkih sredstava za ugrađivanje popunjavati sve uglove oplate i uzane prostore između gusto raspoređenih šipki armature, samo pod dejstvom sopstvene težine, tako da se u završnoj fazi dobije kompaktan beton veće trajnosti. U sastav samozbijajućeg betona, po pravilu, ulaze veoma fini mineralni dodaci, od kojih su najčešće primenjivani krečnjačko i dolomitno brašno, kao i leteći pepeo. U okviru eksperimentalnog rada u ovoj disertaciji je, osim letećeg pepela (poreklom iz dve termoelektrane, TE "Kolubara" i TE "Kostolac") upotrebljen i sprašeni reciklirani beton (dobijen rušenjem dotrajalih armiranobetonskih konstrukcija, odnosno drobljenjem kontrolnih laboratorijskih kocki) i sprašeni elementarni sumpor (koji se dobija kao nusprodukt u naftnoj industriji, u Rafineriji nafte Pančevo). U okviru eksperimentalnog rada spravljeno je i detaljno ispitivano 11 mešavina SCC: dve referentne SCC mešavine sa krečnjačkim brašnom kao mineralnim dodatkom, pet mešavina sa letećim pepelom, tri mešavine sa sprašenim recikliranim betonom i četiri mešavine sa sprašenim sumporom. Prethodno je prilikom definisanja recepture za SCC mešavine spravljeno i ispitano 12 probnih (pilot) mešavina. Sve navedene mešavine, osim dve probne (pilot) mešavine, imale su svojstva koja karakterišu samozbijajuće betone. Podaci o doktorskoj disertaciji iv Primenjena opsežna ispitivanja svežeg i očvrslog SCC su (u skladu sa projektovanim svojstvima u svežem stanju, istraživanim svojstvima u aktuelnim studijama iz konkretne oblasti, kao i raspoloživim količinama komponentnih materijala) uključila veliki broj metoda, sa ciljem detaljnog utvrđivanja svojstava predmetnih SCC. U svežem stanju ispitivani su zapreminska masa, rasprostiranje sleganjem, vremena t500 (kod metode rasprostiranja) i tv (kod metode V-levka), vrednosti merene na L-boksu, U- boksu, sadržaj uvučenog vazduha, a merena je i ambijentalna temperatura kao važan parametar za analizu svojstava svežeg betona. U očvrslom stanju ispitivani su: čvrstoća pri pritisku, čvrstoća pri zatezanju savijanjem, čvrstoća pri zatezanju cepanjem, athezija čeličnih pečata za betonsku podlogu ("pull-off" metoda), statički modul elastičnosti, otpornost prema dejstvu mraza, vodonepropustljivost, otpornost prema dejstvu mraza i soli, nedestruktivna ispitivanja (dinamički modul elastičnosti, rezonantna frekvencija, brzina ultrazvučnog impulsa) sa praćenjem odgovarajućih svojstava do starosti od 180 dana. U cilju bolje karakterizacije strukture betona vršena je i analiza pomoću SEM (Scanning Electron Microscope) metode, praćena odgovarajućim EDS (Enegry Dispersive X-ray Spectrometer) analizama komponentnih materijala i betona sa različitim dodacima. Kada je reč o rezultatima ispitivanja sprovedenih u okviru ovog rada, kod razmatranih SCC mešavina sa letećim pepelom je rasprostiranje sleganjem iznosilo 66.4 cm do 73.8 cm, a vremena merena metodom V-levka bila su u granicama od 15.9 s do 27.2 s. Čvrstoća pri pritisku pri starosti od 28 dana kod ovih SCC mešavina kretala se u granicama od 68.8 MPa do 72.4 MPa, a pri istoj starosti čvrstoće pri zatezanju cepanjem i pri savijanju u granicama 4.2-4.4 MPa i 10.1-11.5 MPa, respektivno. Statički modul elastičnosti pri starosti od 28 dana kretao se u granicama 35.1-37.3 GPa, a dinamički 43.9-45.6 GPa, dok je brzina ultrazvučnog impulsa kroz beton pri istoj starosti bila u granicama od 4668-4720 m/s. Sve SCC mešavine sa letećim pepelom bile su otporne na dejstvo vode pod pritiskom, na simultano dejstvo mraza i soli, a postigle su marku otpornosti na dejstvo mraza M200. Do starosti od 180 dana deformacija skupljanja ovih betona dostigla je vrednosti u granicama 0.487-0.513‰. Što se tiče rezultata ispitivanja SCC mešavina sa sprašenim recikliranim betonom, rasprostiranje sleganjem kod ovih mešavina kretalo se u granicama od 69.5 cm do 73.0 cm, a vremena merena metodom V-levka bila su u granicama od 11.4 s do 13.2 s. Čvrstoća pri pritisku pri starosti od 28 dana kod ovih SCC mešavina kretala se u granicama od 59.2 MPa do 61.6 MPa. Čvrstoća pri zatezanju cepanjem i pri savijanju kod ovih serija kretala se u granicama 3.4-3.6 MPa (pri starosti od 63 dana) i 8.9-9.4 MPa (pri starosti od 180 dana), respektivno. Pri starosti od 28 dana dinamički modul elastičnosti SCC mešavina sa sprašenim recikliranim betonom kretao se u granicama 44.2-44.9 GPa, dok je brzina ultrazvučnog impulsa kroz beton pri istoj starosti bila u granicama od 4669-4681 m/s. Sve SCC Podaci o doktorskoj disertaciji v mešavine sa sprašenim recikliranim betonom bile su otporne na dejstvo vode pod pritiskom. Kada je reč o SCC mešavinama sa sprašenim sumporom, rasprostiranje sleganjem kod ovih mešavina iznosilo je 77.5 cm do 82.0 cm, a vremena merena metodom V-levka bila su u granicama od 8.2 s do 10.5 s. Čvrstoća pri pritisku pri starosti od 28 dana kod ovih SCC mešavina kretala se u granicama od 54.6 MPa do 62.2 MPa. Čvrstoća pri savijanju kod ovih serija kretala se u granicama 6.9-8.6 MPa (pri starosti od 180 dana). Pri starosti od 28 dana dinamički modul elastičnosti SCC mešavina sa sprašenim sumporom kretao se u granicama 41.5-43.4 GPa, dok je brzina ultrazvučnog impulsa kroz beton pri istoj starosti bila u granicama od 4589-4636 m/s. Na osnovu rezultata ispitivanja u radu su izvedeni odgovarajući zaključci u vezi sa promenom razmatranih fizičko-mehaničkih svojstava različitih SCC mešavina u zavisnosti od količine, porekla i vrste upotrebljenog mineralnog dodatka. Izvršeno je i poređenje razmatranih fizičko-mehaničkih svojstava SCC mešavina sa različitim mineralnim dodacima i izvedeni su odgovarajući zaključci. Rezultati ispitivanja obavljenih u okviru ove disertacije upoređeni su sa rezultatima dostupnim iz literature, te je data odgovarajuća diskusija u vezi sa time. U slučajevima kada je to bilo moguće, metodom regresione analize izvedeni su i izrazi za analitičke zavisnosti razmatranih svojstava SCC mešavina, sa odgovarajućim koeficijentima korelacije. Primena principa održivog razvoja u graditeljstvu osnovni je motiv za usvojenu koncepciju istraživanja iz ovog rada. Upotreba industrijskih nusprodukata u svojstvu mineralnog dodatka (filera) kritički je procenjena sa aspekta njihovog uticaja na svojstva SCC betona u svežem i očvrslom stanju. Povećanje količine raspoloživih resursa za spravljanje SCC mešavina sa jedne i pozitivan uticaj na životnu sredinu putem smanjenja količine ovih materijala na deponijama, sa druge strane, dva su osnovna pozitivna efekta koja bi trebalo da proizađu iz predmetnog istraživanja.

Concrete, as one of the most commonly used materials in the construction industry, has evolved with the development of construction, from the beginning to the present day. Placing of conventional concrete is usually done with the use of vibrating equipment to help in reduction of entrained air content, eliminating the possibility of cavities occurrence in contact with reinforcement and formwork (the so-called Normal Vibrated Concrete, NVC). Concrete becomes more compact, denser and more homogeneous, which are the basic aspects for an acceptable behavior in the structure. This operation, compaction, traditionally plays a key role in the production of high quality concrete, with optimum strength and durability. Development of superplasticizers (chemical admixtures for concrete) allowed easier placing of concrete with stiffer consistency; a small dosage of this type of chemical admixtures can reduce the friction between the particles, which results in more mobile and workable concrete (concrete with fluid consistency) that is easier to place in formwork, while maintaining the same amount of water. Extrapolation of the concept of the superplasticizers use towards obtaining concrete with fluid consistency led to the concept of Self-compacting Concrete - SCC for short. Self- compacting concrete, is defined as a concrete mix that can be placed purely by means of its own weight, with little or no vibration and is a highly flowable concrete that spreads into place, fills formwork, and wraps even the most congested reinforcement, and showing no signs of segregation. Typically, SCC contains certain quantities of very fine mineral additions; the most commonly applied are limestone and dolomite powder and fly ash. Within the experimental work in this thesis, besides fly ash (originating from two power plants, "Kolubara" and "Kostolac"), recycled pulverized concrete (obtained by demolition of old concrete structures) and powdered elemental sulfur (which is obtained as a by-product of the petrol industry, in Pancevo Oil Refinery). Within this experimental work, 11 mixtures of SCC were prepared, two reference SCC mixtures with limestone powder as mineral addition, five mixtures with fly ash, three mixtures with ground recycled concrete and four mixtures with ground elemental sulfur. Also, during the proces of defining the composition of SCC mixtures, 12 test (pilot) mixutures were made and investigated. All mixtures, except two test mixtures, could be characterized as self-compacting concrete, based on their fresh properties. The applied extensive testing of fresh and hardened SCC (with respect to the designed properties of fresh SCC, the research findings of the recent Data on doctoral dissertation vii studies in the world, and also with respect to the available quantities of component materials) included a number of methods, with the aim of determining the detailed properties of these SCC mixtures. Fresh SCC investigations included: density, slump flow, t500 and V-funnel (tV) times, the values measured in the L-box, U-box, entrained air content, and also measuring the ambient temperature, as an important parameter for the analysis of the properties of fresh concrete. Hardened SCC properties testing included: compressive strength, tensile flexural strength, tensile splitting strength, adhesion of the steel seals to the concrete surface ("pull- off" method), static modulus of elasticity, water tightness, resistance to the effects of freeze and thaw, resistance to the combined effects of frost and salt, non-destructive testing (dynamic elastic modulus, the resonance frequency, the ultrasonic pulse velocity), with the properties monitoring during period of 180 days. In order to better characterize the structure of concrete, the analysis using the SEM microscope was performed, with the corresponding EDS (Enegry Dispersive X-ray Spectrometer) analysis of the component materials of concrete with different mineral additions. As for the results of experimenal investigations, slump flow for all SCC mixtures with fly ash was 66.4-73.8 cm, while V-funnel measured times were 15.9-27.2 s. Compressive strength of 28 days old samples was in a range of 68.8-72.4 MPa for all SCC mixtures, while, at the same age of samples, splitting tensile strength and flexural strength ranged 4.2-4.4 MPa and 10.1-11.5 MPa, respectively. Modulus of elasticity (static) was 35.1- 37.3 GPa and dynamic modulus of elasticity was 43.9-45.6 GPa, while ultrasonic pulse velocity through investigated SCC mixtures amounted to 4668-4720 m/s, all at 28 days. The investigated SCC mixtures proved to be watertight, resistant to combined effects of frost and salt, freeze and thaw, and reached freeze and thaw grade of M200 (200 cycles of freeze and thaw). Shrinkage deformations reached values in a range of 0.487-0.513‰, through the period of 180 days. Regarding SCC mixtures with ground recycled concrete, slump flow for all SCC mixtures was 69.5-73.0 cm, while V-funnel measured times were 11.4-13.2 s. Compressive strength at the age of 28 days ranged from 59.2 MPa to 61.6 MPa. Splitting tensile strength and flexural strength ranged 3.4-3.6 MPa (at 63 days) and 8.9-9.4 MPa (at 180 days), respectively. At the age of 28 days, dynamic modulus of elasticity of SCC mixtures with ground recycled concrete ranged 44.2-44.9 GPa, while ultrasonic pulse velocity through concrete at the same age reached 4669-4681 m/s. Investigation showed that these SCC mixtures proved to be water resistant. As for the SCC mixtures with ground sulfur, slump flow of these mixtures was 77.5-82.0 cm, and V-funnel times were measured within 8.2 s and 10.5 s interval. Compressive strength at 28 days was 54.6-62.2 MPa. Flexural strength at the age of 180 days was in the range of 6.9-8.6 MPa. At the age of 28 days, dynamic modulus of elasticity of SCC mixtures with ground sulfur was 41.5-43.4 GPa and ultrasonic pulse velocity through concrete at the same age was 4589-4636 m/s. Data on doctoral dissertation viii Based on the results presented in this work, conclusions have been drawn regarding the change of monitored physical and mechanical properties of different SCC mixtures, as a function of quantities, origin and type of used mineral additions. Comparison of monitored physical and mechanical properties of different SCC mixtures with different mineral additions was also performed, leading to adequate conclusions. Results of investigations performed in this work have been compared with the results of other researchers, with related discussion. Whenever it was possible, analytical correlations were calculated with suitable correlation coefficients, using method of regression analysis. Application of the principles of sustainable development in building industry was the motive for the adopted concept of research in this paper. The use of industrial by-products as a mineral supplement (filler) was critically evaluated in terms of their influence on the properties of SCC in the fresh and hardened state. Increase of the amount of available resources for making SCC mixtures, with a positive impact on the environment by reducing the amount of these materials in landfills, on the other hand, present two main positive effects that should arise from this research.

Unapređenje metodologije kontrole ugiba armiranobetonskih konstrukcija

Improved method for deflection control of reinforced concrete structures

Napredak u razvoju alata za projektovanje građevinskih konstrukcija nije pratila odgovarajuća podrška u oblasti provere deformacija armirano- betonskih elemenata. Većina softvera, koji su danas u upotrebi, koristi metod konačnih elemenata. Standardni tipovi konačnih elemenata u komercijalnim softverima ne podržavaju prikladno izračunavanje ugiba betonskih konstrukcija sa uključivanjem efekata nastanka prslina i skupljanja i tečenja betona. S druge strane, upotreba konstrukcionih materijala visokih čvrstoća omogućava smanjivanje dimenzija nosećih elemenata. Zbog povećane deformabilnosti, provera ugiba postaje neophodna, a sam uslov ograničenja deformacija često merodavan za projektovanje. Većina propisa i preporuka za projektovanje daje dva načina za proveru ugiba. Pojednostavljeni načini omogućavaju brz i jednostavan proračun. Uobičajeno su na strani sigurnosti i, stoga, zahtevaju veće dimenzije konstrukcijskih elemenata. Za razliku od njih, složeniji načini zahtevaju obimniji proračun koji uključuje relevantne osobine betonskih konstrukcija, uslova sredine i procesa gradnje, ali često omogućavaju manje dimenzije elemenata. Ovakvi proračuni, osim što nisu brzi, zahtevaju i dodatna znanja. Evrokod 2 (EN 1992-1-1:2004) za proračun betonskih konstrukcija takođe daje dva načina za kontrolu ugiba. Pojednostavljeni način dat je u obliku graničnog odnosa raspon/statička visina. Ovaj postupak nije dobro pripremljen za praktičnu upotrebu i ima ozbiljna ograničenja: kriterijum je izveden za neodgovarajući odnos kvazi-stalnog i graničnog opterećenja. Osim toga, nije obuhvaćena pritisnuta armatura koja nije neophodna prema graničnom stanju nosivosti. Drugi način je zasnovan na opštem postupku izračunavanja ugiba – integraljenju krivine duž elementa. Za proračun dugotrajnih efekata usled skupljanja i tečenja betona koristi se metoda efektivnog modula. Uticaj nastanka prslina na krutost nosača modelira se interpolacionim koeficijentom prema CEB-FIP Model kodu 1990. Ni ovaj način nije naročito prikladan za praktične proračune: u slučaju statički neodređenih konstrukcija, momentni dijagram koji se dobija standardnim inženjerskim proračunom, metodom konačnih elemenata sa krutostima bruto preseka, nije odgovarajući za izračunavanje krivina. Usled nastanka prslina i skupljanja i tečenja betona dolazi do preraspodele momenata savijanja koja može imati i velikog uticaja na izračunati ugib. Opcija preraspodele uglavnom nije podržana softverima koji se koriste za projektovanje što izračunavanje ugiba čini veoma složenim. U tezi je prezentiran unapređeni metod za kontrolu ugiba zasnovan na integraljenju krivina. Metod sledi postupak Evrokoda 2 za proračun efektivnih krivina i uključuje potrebne preraspodele momenta savijanja. Razvijen je za linijske elemente i ploče koje nose u jednom pravcu, za jednakopodeljeno dugotrajno (kvazi-stalno) opterećenje. Izvedeni su algebarski izrazi za izračunavanje ugiba korišćenjem originalnog sistema bezdimenzionih parametara. Vrednosti svih bitnih činilaca za proračun ugiba (koeficijent tečenja, dilatacija skupljanja, čvrstoća na zatezanje i modul elastičnosti betona, dimezije preseka, količina i raspored zategnute i pritisnute armature, raspon nosača i nivo opterećenja) mogu se slobodno birati u granicama uobičajenih vrednosti. Izračunati algebarski rezultat je blizak onom koji se dobija numeričkim integraljenjem krivine za nekoliko osnovnih statičkih sistema (prosto i kontinualno oslanjanje). Razvijeni metod je podesan za praktične inženjerske proračune. Kao nezavisna studija, poređeni su rezultati proračuna ugiba rigoroznim metodom Evrokoda 2 sa merenim vrednostima na armiranobetonskim gredama i pločama. Mereni ugibi iz 6 eksperimentalnih programa iz literature (4 na prostim gredama, sa 29 rezultata, i 2 na kontinualnim gredama, sa 10 rezultata – ukupno 66 eksperimentalnih nosača) pokazali su dobro slaganje sa izračunatim vrednostima. Sprovedeni su i nelinearni proračuni ugiba konačnim elementima, metodom korak-po-korak, korišćenjem DIANA softvera. Rezultati proračuna nekoliko nosača takođe su upoređeni sa rezultatima dobijenim prema Evrokodu 2. Na osnovu ovih analiza formulisano je nekoliko smernica za kalibraciju modela Evrokoda 2.

Development of design tools for reinforced concrete is not followed with convenient procedures for the deflection check. Most of the software using finite element calculation does not support proper evaluation (including effects of cracking, creep and shrinkage) of the deflection of concrete structures. Use of high strength materials enables reduction of the size of structural elements. As a result, structures become more deformable and it is necessary to check deflection. Simplified and refined methods are usually presented by most of design codes or recommendations for the deflection check. The simplified methods provide faster and easier calculation. They are generally on the safe side and require enlarged dimensions of structural elements. The refined methods involve relevant properties of concrete, environmental conditions and construction schedule, allowing for optimization of the size of structural elements. Apart from not being suitable for hand calculation, they often require some additional knowledge. Eurocode 2 (EN 1992-1-1:2004) also provides two methods for the deflection check. Simplified criterion is in a form of span-to-depth ratio limit. This tool has serious limits. It is not well prepared for practical use (it is derived for an unsuitable ratio of the quasi-permanent to the ultimate load; it also does not include the compressive reinforcement other then required for ULS). The second, rigorous method is based on general approach for deflection calculation - integration of the curvatures along the element. The effective modulus method is used for calculation of long-term effects due to creep and shrinkage of concrete. Influence of concrete cracking to the stiffness is introduced by interpolation coefficient according to CEB-FIP Model code 1990. This more refined method seems to be easy applicable due to lack of the very important instruction: bending moment diagram of the statically indeterminate structures, resulting from an ordinary ULS analysis based on concrete gross sections, should be redistributed to account for effects of cracking, creep and shrinkage. This option is not usually supported by common engineering software and task becomes heavy. Evaluation of the redistributed diagram requires a time-dependant stiffness matrix and an iterative calculation following appearance of cracks. An improved method for deflection calculation of reinforced concrete elements based on the integration of curvatures is presented in Thesis. It follows Eurocode 2 instructions for calculation of the curvatures and includes the necessary redistribution of bending moments. The method is developed for beam elements of rectangular section and one-way slabs for the long-term (quasi-permanent) uniform load. The algebraic expressions for calculation of the deflection are derived using original system of dimensionless parameters. All relevant design parameters for the deflection calculation (creep coefficient, shrinkage strain, tensile strength and modulus of concrete, cross section dimensions, area and arrangement of tensile and compressive reinforcement, span and load level) are left open for an arbitrary choice within common limits. Calculated result is close to the result obtained by integration of curvatures for several basic structural systems (simple and continuous beams). Developed method is suitable for engineering purposes, including hand calculation. As an independent study, results of deflection calculation obtained by rigorous method of Eurocode 2 are compared with experimentally measured deflections of reinforced concrete beams and slabs. Results provided from six experimental programs available from literature (4 on simple beams, with 29 results, and 2 on continuous beams, with 10 results – total of 66 experimental girders) were in good compliance with the calculated deflections. DIANA software was also used for nonlinear finite element step-by-step analysis. Calculated deflections for several examples are compared with results obtained by numerical integration of curvatures according to Eurocode 2. Comparisons with experimental results and refined non-linear analysis are summarized into some guidelines for calibration of the method.

Turizam Šumadijskog okruga u kontekstu održivog razvoja

Tourism in Šumadija county in the context of sustainable development

Mnoge zemlje u razvoju, suočene sa teretom dugova i pogoršanjem trgovinskih uslova, su se okrenule promociji turizma u nadi da će im razvoj turizma obezbediti prihode i nove investicije. Sposobnost turizma da generiše devizne prihode, da omogući otvaranje novih radnih mesta, i apsorbuje nezaposlenost obezbeđuje mu politički i društveni legitimitet. Potencijal turizma za stvaranje novih radnih mesta je takođe važan, jer je nezaposlenost glavni društveni i ekonomski izazov sa kojima se suočavaju mnoge zemlje u razvoju. Održivi razvoj turizma je razvoj turizma koji obezbeđuje dugoročan stabilan rast u kojem turistički promet ne ugrožava ravnotežu ekološke odgovornosti, ekonomske efikasnosti i društveno odgovornog turizma. WTO je definisao održivi razvoj turizma kao zadovoljavanje potreba prisutnih turista i lokalnog stanovništva, uz istovremenu zaštitu i podsticanje mogućnosti za budućnost. Održivi razvoj turizma zahteva menadžment svih sredstava da bi se ispunile ekonomske i socijalne potrebe uz održavanje kulturnog integriteta i osnovnih ekoloških procesa i biološkog diverziteta. Masovnost turističkih poseta koja nastaje kao posledica globalizacije vrši pritisak na osnovne resurse na kojima turizma počiva, pre svega kroz degradaciju životne sredine, zbog čega se javlja potreba primene koncepta održivog razvoja u turističkoj delatnosti. Utvrđivanjem trenutnog stanja i analizom postojećih potencijala stvaraju se preduslovi za usmeravanje budućeg turističkog razvoja u pravcu održivosti. Šumadijski okrug poseduje značajne potencijale za razvoj turizma zahvaljujući brojnim prirodnim i antropogenim turističkim vrednostima. Vidovi turizma na koje bi trebalo obratiti posebnu pažnju su poslovni, seoski, tranzitni, gradski, vinski, sportsko-rekreativni, lovni, ekskurzioni, banjski, kulturno-manifestacioni i ekoturizam. Raznovrsnost turističkih sadržaja garantuje vredno turističko iskustvo i konkurentan turistički proizvod u nacionalnim i međunarodnim okvirima. Razvoj pomenutih vidova turizma zavisi od odnosa koji prema njemu imaju sve zainteresovane strane za njegov razvoj, a pre svega turističke organizacije i lokalne vlasti, ali zavisi i od stava lokalnog stanovništva. Ako se turistički razvoj bazira na principima održivog razvoja ostvaruje se dugoročna korist za lokalnu zajednicu. Naučno istraživanje obuhvata ispitivanje stavova koje imaju zaposleni u turističkim organizacijama u Šumadijskom okrugu koji su važan faktor u usvajanju koncepta održivog turističkog razvoja, kao i ispitivanje odnosa koji lokalno stanovništvo ima prema održivom razvoju turizma. Bez institucionalne podrške, kao i bez podrške lokalnog stanovništva održivi razvoj turizma je skoro nemoguće realizovati.

Facing the burden of debt and negative trends in trading environment, many developing countries have turned to the promotion of tourism in the hope that the development of tourism would provide income and new investments. Tourism’s ability to generate income in foreign currencies, to provide new jobs and thus absorb unemployment gives it political and social legitimacy. Tourism’s potential for providing new jobs is also significant, since unemployment is a major social and economic challenge faced by many developing countries. Sustainable development of tourism is the kind of tourism development that allows a stable long-term development without jeopardizing the balance between ecological responsibility, economic efficacy, and socially responsible tourism. Sustainable development of tourism is defined by WTO as the fulfillment of the needs of the tourists as well as of the local population, which is at the same time protecting and stimulating future possibilities. Sustainable development of tourism requires proper management of all resources in order to satisfy economic and social needs, and to preserve cultural integrity, basic ecological processes and biological diversity. Massive scale tourism, a consequence of globalization, puts fundamental tourist resources under pressure, most significantly by degrading the environment, which brings about the need for sustainable development in tourism. By ascertaining the present situation, and by analyzing existing potential, conditions are being met for establishing the guidelines that will help lead future tourist development towards sustainability. Due to a large number of natural and anthropogenic tourist qualities, Šumadija county has significant potential for tourism development. Business, country, transit, city tourism, wine, sports, hunting tourism, as well as excursion, spa, cultural, and ecotourism, are especially note- worthy in this context. Diversified tourist content guarantees valuable tourist experiences and competitive tourist product both in national and international contexts. The development of the aforementioned types of tourism depends on the attitudes of all interested parties, but primarily on the attitudes of the tourist organization local authorities, and local population. Development of tourism based on the principles of sustainable development results in long-term benefits for the local community. The research conducted covers an analysis of the attitudes and opinions of the Šumadija county tourist organization employees (since they are an important factor in the process of acceptance of the concept of sustainable development of tourism) as well as an analysis of the attitudes of local population towards sustainable development of tourism. Sustainable development of tourism is almost impossible to realize without institutional support and without the support of local population.

Neparametarsko generisanje stohastičkih hidroloških vremenskih serija

Non-parametric generation of stochastic hydrologic time series

Predmet istraživanja u ovoj disertaciji je neparametarska metodologija za stohastičko generisanje dugačkih hidrometeoroloških serija podataka...

This dissertation deals with the development of non-parametric methodology for stohasticgeneration of hydrometeorological series..

Šumski ekosistemi Srbije u funkciji zaštite životne sredine od negativnog uticaja klimatskih promena

Forest ecosystems of Serbia in the function of environmental protection from negative climate changes impact

Doktorska disertacija pod nazivom „Šumski ekosistemi Srbije u funkciji zaštite životne sredine od negativnog uticaja klimatskih promena“ ima za cilj da teorijskim istraživanjima ukaže na značaj šumskih ekosistema u zaštiti životne sredine, posebno sa aspekta ublažavanja uticaja negativnih klimatskih promena i potrebu primene tzv. prilagodljivog (adaptibilnog) gazdovanja u šumarskoj praksi, a u cilju uspostavljanja održivog razvoja šuma i šumskih ekosistema u Srbiji. Neposredni zadaci istraživanja bili su: - da se na osnovu elemenata vezanih za globalne i regionalne promene klime vrednuje njihov uticaj na šumske ekosisteme i životnu sredinu; - da se formiranjem elektronske baze klimatoloških parametara za period 1949-2010. godina za 32 meteorološke stanice u Srbiji i obradom dobijenih podataka sagledaju klimatski elementi u Srbiji; - da se na osnovu sprovedenih komparativnih analiza daju smernice koje bi služile pri planiranju radova na pošumljavanju i gajenju šuma, u cilju adaptacije šumskih ekosistema na novonastale klimatske uslove i što boljeg odabira otpornijih vrsta i odgovarajućih tehnika sadnje; - da se definišu potencijalne strateške i operacione metode u cilju adaptacije šumskih ekosistema na izmenjene klimatske uslove i realizacije adaptibilnog gazdovanja šumama u Srbiji zasnovanog na principima održivog razvoja; - sagledavanje mogućih promena u šumskim ekosistemima (prema različitim scenarijima globalnih promena klime) i predlog dugoročnih mera zaštite i održivog korišćenja; - utvrđivanje efekata klimatskih promena na raspoloživost šumskih i drugih ekosistema i biodiverziteta u cilju planiranja održivog razvoja i ekološki prihvatljivih delatnosti na područjima osetljivim na klimatske promene...

Doctoral dissertation "Forest ecosystems of Serbia in the function of environmental protection from negative climate changes impact" with theoretical researches tends to indicate the importance of forest ecosystems in environmental protection, particularly in terms of mitigation of adverse effects of climate change, and the need to use so-called flexible (adaptive) management in forest practice, with the aim to establish a sustainable development of forests and forest ecosystems in Serbia. The immediate objectives of the research were: - to evaluate impact of elements related to global and regional climate change on forest ecosystems and the environment; - to observe climate elements in Serbia by creating an electronic database of climatological parameters for the period 1949-2010 for 32 meteorological stations in Serbia and by processing of the obtained data; - on the basis of conducted comparative analyses to provide guidelines for planning activities on afforestation and silviculture in order to adapt forest ecosystems to the new climate conditions and to make better selection of more resistant species and appropriate planting techniques; - to define potential strategic and operational methods in order to adapt forest ecosystems to changed climate conditions and realization of adaptive forest management in Serbia based on the principles of sustainable development; - to perceive possible changes in forest ecosystems (due to the different scenarios of global climate change) and propose a long-term protection measures and sustainable use of forest ecosystems; - to determine the effects of climate change on the availability of forest and other ecosystems and biodiversity in order to plan sustainable development and environmentally friendly activities in areas vulnerable to climate change...

Ekonometrijska analiza premije zarada javnog sektora u Srbiji u uslovima fiskalne konsolidacije / Marko D. Vladisavljević.

Univerzitet u Beogradu, Ekonomski fakultet., 2018, doktor nauka, Ekonomija.

U 2014. godini, fiskalni deficit u Republici Srbiji iznosio je 6,6% bruto društvenog proizvoda (BDP) i bio je među najvišim u Evropi. Reagujući na deficit, Vlada Srbije je, krajem 2014. godine donela mere fiskalne konsolidacije koje su, između ostalog, uključivale i smanjivanje zarada u javnom sektoru u iznosu od 10% za zarade više od 25.000 dinara. Osnovni cilj ove disertacije bio je da se detaljno ispitaju efekti fiskalne konsolidacije na premiju zarada javnog sektora (razliku u zaradama između javnog i privatnog sektora kada statistički kontrolišemo efekte ostalih relevantnih varijabli), ali i efekti koje je fiskalna konsolidacija imala na ostale ishode na tržištu rada. S tim u vezi, u ovoj disertaciji detaljno su prikazani ekonometrijski metodi kojima se ocenjuje premija zarada javnog sektora, ali i metode koje možemo da koristimo da ocenimo efekte fiskalne konsolidacije na promenu premije. Korišćena je najpre Minserova jednačina zarada, u kojoj se premija zarada javnog sektora računa kao koeficijent uz veštačku promenljivu koja označava rad u javnom sektoru. Nakon toga, premija zarada javnog sektora ocenjena je uz pomoć Blajnder-Ohaka dekompozicije, u okviru koje se ukupna razlika u zaradama između sektora razdvaja na objašnjeni i neobjašnjeni deo. Objašnjeni deo se duguje različitim karakteristikama radnika u javnom i privatnom sektoru (različiti nivoi obrazovanja, radno iskustvo itd.), dok se neobjašnjeni deo duguje razlikama u uslovnim zaradama za te karakteristike na tržištu rada i kao takav predstavlja još jednu ocenu premije zarada javnog sektora. Premija zarada javnog sektora zatim je ocenjena i drugim metodama dekompozicije. Kod JMP dekompozicije, ukupna razlika u zaradama deli se na tri komponente: razliku u karakteristikama (Q), razliku u cenama (P), koja predstavlja ocenu premije zarada javnog sektora, i razliku u neopaženim karakteristikama i cenama (U), a koja se procenjuje na osnovu razlika u distribuciji reziduala dva sektora. U okviru Nopo dekompozicije, najpre se određuje deo uzorka u kojem su radnici u dva sektora uporedivi iz perspektive karakteristika na tržištu rada, a zatim se u okviru uporedivog dela uzorka razlika u zaradama deli na deo koji se duguje razlikama u karakteristikama i deo koji predstavlja premiju zarada javnog sektora. Konačno, Njuman-Ohaka dekompozicija uzima u obzir Hekmanovu ideju da radnici ne biraju (nisu izabrani u) javni ili privatni sektor na slučaj, usled čega su ocene koeficijenata u Minserovoj iv regresiji i Blajnder-Ohaka dekompoziciji pristrasne. Ocenjujući selekciju u javni sektor zajedno sa jednačinom zarada ocene koeficijenta postaju nepristrasne. Da bismo ocenili premiju zarada javnog sektora na različitim nivoima distribucije zarada korišćene su i metode uslovne kvantilne regresije. Dodatno, koristimo strukturu rotirajućeg panela Ankete o radnoj snazi da 1) direktno proverimo hipotezu o tome da je fiskalna konsolidacija uticala na smanjivanje zarada javnog sektora i 2) da ocenimo efekte fiskalne konsolidacije na tranzicije na tržištu rada. Konačno, koristimo metode kointegracione analize i vektorskog autoregresionog modela da ispitamo dugoročnu povezanost zarada u dva sektora. Istraživanje u okviru disertacije pokušava da potvrdi ili opovrgne četiri hipoteze. Prvom hipotezom ispitujemo da li je fiskalna konsolidacija u Srbiji izazvala smanjenje premije zarada javnog sektora u Srbiji 2015. i 2016. godine, u odnosu na 2014. godinu. Prva hipoteza je, prema očekivanjima, potvrđena, jer je premija smanjena sa 17,3% u 2014. godini na 11,3% (11,1%) u 2015. (2016.) godini, a slični rezultati i zaključci dobijaju se primenom različitih metoda dekompozicije zarada. Direktno modeliranje predloženih mera smanjenja zarada kroz panel analizu pokazalo je da se fiskalna konsolidacija, u proseku, odvijala prema planu koji je donela Vlada Srbije i da je upravo fiskalna konsolidacija dovela do smanjenja premije zarada javnog sektora. Dodatno, u okviru ove hipoteze, posebna pažnja posvećena je podeli na sektor države (koji obuhvata sektore državne administracije, obrazovanja i zdravstva) i sektor javnih preduzeća. Pokazano je da je premija za rad u javnim preduzećima u Srbiji u 2014. godini bila značajno viša nego u sektoru države, za oko 3 procentna poena; i da je konsolidacija dodatno doprinela povećanju razlika u uslovnim prosečnim zaradama u dva sektora, (6,7% u 2015.; i 9,8% 2016. godini). Modeliranje predloženih mera smanjenja zarada u okviru panel analize ukazuje da je na povećanje razlika u zaradama između podsektora javnog sektora uticala različita saglasnost predloženih i realnih promena zarada u dva podsektora: dok je u sektoru države saglasnost bila potpuna, u sektoru javnih preduzeća ona je bila samo delimična. Primena metoda dekompozicije ukazuje na to da su nekorigovane razlike u zaradama između sektora izraženije od premije zarada, zbog toga što radnici u javnom sektoru imaju bolje karakteristike na tržištu rada (više nivoe obrazovanja, bolju strukturu v zanimanja itd.), a slično važi i za radnike sektora države u odnosu na radnike javnih preduzeća. Metode dekompozicije ukazuju i da su osnovni uzroci premija zarada javnog sektora više uslovne zarade za više nivoe obrazovanja, duže radno iskustvo i za pojedina zanimanja, dok su više ceteris paribus zarade u javnim preduzećima, u odnosu na sektor države, posledica faktora koje ne možemo da opazimo u podacima. Rezultati kvantilne regresije ukazuju da je premija zarada javnog sektora u Srbiji u 2014. godini bila različita na različitim nivoima distribucije zarada. Premija je bila najviša na najnižim zaradama (21% na 10. percentilu), statistički značajno niža na nivou medijane (16,9%), i najniža na najvišim zaradama (12,4%). Usled ovih razlika i izuzimanja zarada nižih od 25.000 dinara iz fiskalne konsolidacije, u okviru druge hipoteze ispitujemo da li je smanjivanje premije javnog sektora 2015. i 2016. godine bilo je različito na različitim nivoima distribucije zarada. I ova hipoteza je potvrđena: rezultati kvantilne regresije ukazuju na to da na niskim nivoima zarada promene premije nisu bile statistički značajne, dok su promene od 30. percentila pa do kraja distribucije zarada, značajne i pri tome više izražene na vrhu nego na sredini distribucije zarada. I u okviru ove hipoteze razmatrali smo različite efekte na podsektore javnog sektora: sektor države i sektor javnih preduzeća. Analiza ukazuje na dva važna nalaza. Prvo, rezultati iz 2014. godine ukazuju da u sektoru države, u odnosu na privatni sektor, postoji teorijski očekivan obrazac premije zarada: visoka premija na dnu i niska premija na vrhu distribucije zarada, dok se kod javnih preduzeća premija zarada u odnosu na privatni sektor ne razlikuje u zavisnosti od nivoa u distribuciji zarada. Usled ovog trenda, počevši od medijane pa do najviših zarada, premija je viša za sektor javnih preduzeća nego za sektor države. Drugo, između 2014. i 2015 godine smanjenje premije zarada u sektoru države bilo je značajno na svim nivoima distribucije zarada (osim na 10. percentilu), dok je u sektoru javnih preduzeća smanjenje premije bilo značajno samo kod visokih zarada. Uz to, intenzitet promena bio je značajno viši u sektoru države nego u sektoru javnih preduzeća na svim nivoima distribucije zarada. Ovi rezultati, zajedno sa rezultatima u okviru prethodne hipoteze ukazuju na to da su mehanizmi i faktori koji utiču na formiranje zarada i mogućnosti reagovanja u situaciji fiskalne konsolidacije javnih preduzeća i sektora države različiti. vi U okviru treće hipoteze pretpostavili smo da će fiskalna konsolidacija izazvati i strukturne efekte na tržištu rada. Prema ovoj hipotezi, javni sektor, usled smanjivanja zarada, postaje manje korisna opcija radnicima, koji mogu da odluče da, umesto rada u javnom sektoru, rade u privatnom sektoru, ili da se povuku u neaktivnost. Direktno ispitivanje efekata smanjivanja zarada kroz panel analizu ukazalo je na to da ova hipoteza nije potvrđena, te da efekti fiskalne konsolidacije nisu povećali verovatnoću tranzicije radnika u privatni sektor ili neaktivnost. Konačno, u okviru četvrte hipoteze ispitivali smo da li je smanjivanje zarada u javnom sektoru, kao posledica fiskalne konsolidacije, uticalo je i na smanjivanje zarada u privatnom sektoru. Ispitivanje dugoročne povezanosti između zarada u sektoru države i sektoru prerađivačke industrije, kao reprezentativnih sektora javnog i privatnog sektora ukazalo je na to da su zarade u dva sektora kointegrisane, tj. da između njih postoji dugoročna ravnotežna veza. Ipak, ispitivanje u okviru VAR modela i modela sa korekcijom ravnotežne greške ukazuje na to da zarade u sektoru prerađivačke industrije utiču na zarade u sektoru države, dok obrnuto ne važi. Drugim rečima, četvrta hipoteza nije potvrđena: fiskalna konsolidacija nije uticala na zarade u privatnom sektoru, jer one nisu pod uticajem niti kratkoročnih niti dugoročnih promena zarada u javnom sektoru.

In 2014, the fiscal deficit in the Republic of Serbia amounted to 6.6% of GDP and was among the highest in Europe. In response to the deficit, the Government of Serbia adopted a set of fiscal consolidation measures at the end of 2014, which included a 10% reduction of public sector wages for wages higher than 25,000 RSD. The main objective of this dissertation was to examine the effects of fiscal consolidation on the public sector wage premium (defined as the difference between public and private sector wages, when statistically controlling for the effects of other relevant variables); as well as the effects that fiscal consolidation had on other labour market outcomes. The dissertation presents econometric methods used to assess the public sector wage premium, and the effects of fiscal consolidation on the change of premium. Firstly, we used Mincer earnings equation, in which public sector wage premium is estimated as a coefficient next to the dummy variable for the public sector job. Subsequently, the public sector wage premium was estimated via Blinder-Oaxaca decomposition, in which the total difference in wages between the sectors is divided to explained and unexplained part. While the explained part is attributed to different labour market characteristics of the workers from public and private sectors (different levels of education, work experience, etc.), the unexplained part is due to different constants and returns to characteristics, and represents an estimate of the public sector wage premium. The public sector wage premium was then estimated by other decomposition methods. Within JMP decomposition, total wage difference is divided to: the difference in characteristics (Q), the difference in prices (P), which represents an estimate of the public sector wage premium, and the difference in unobserved characteristics and prices (U), estimated based on the differences in the distributions of the wage equation residuals. Nopo decomposition suggests that labour market characteristics of the workers from two sectors are not fully comparable. Therefore, after determining the comparable sample, the difference in earnings within the comparable part of the sample is divided to two parts: first – due to differences in characteristics and second which represents the public sector wage premium. Finally, the Neuman-Oaxaca decomposition takes into account Heckman's notion that workers do not choose (are not selected to) public or private sector randomly, therefore causing a bias in Mincer's regression and viii Blinder-Oaxaca decomposition estimates. Joint estimate of the selection into the public sector and of the wage equation corrects for this bias. In order to estimate the public sector wage premium at different parts of the wage distribution we used the conditional quantile regression. In addition, we used the Labour Force Survey rotating panel structure to 1) directly examine the hypothesis that fiscal consolidation has influenced the reduction of the public sector wages and 2) to assess the effects of fiscal consolidation on labour market transitions. Finally, we use the methods of cointegration analysis and vector autoregression model to examine the long- term relationship of wages in the public administration and the manufacturing sector. The research within the dissertation is organised around four hypotheses. The first hypothesis investigates whether fiscal consolidation in Serbia has caused a reduction in the public sector wage premium in Serbia in 2015 and 2016, compared to 2014. The first hypothesis was, expectedly, confirmed, since the premium was reduced from 17.3% in 2014 to 11.3% (11.1%) in 2015 (2016). Similar results and conclusions are obtained by applying different methods of wage decomposition. Direct modelling of proposed measures of wage reduction through panel analysis showed that wage reduction, on average, was in line with the plan adopted by the Government of Serbia and that wage reduction indeed led to reduction of the public sector wage premium. Additionally, within this hypothesis, we investigated the differences between the state sector and state-owned enterprises within the public sector. The results indicate that the conditional wages in the state-owned enterprises in Serbia in 2014 were significantly higher than in the state sector, by about 3%, while the effects of fiscal consolidation further contributed to the increase of the conditional wage differences between the sectors (6.7% in 2015, and 9.8% in 2016). The modelling of the proposed measures within the panel analysis suggests that the increase in wage differentials between the public sector subsectors was influenced by the different compliance of proposed and real changes: while in the state sector we observe full compliance, in the state-owned enterprises the compliance was partial. Decomposition methods further suggest that unadjusted wage differences between the sectors are even more pronounced than the wage premiums, due to better labour market characteristics of the public sector workers (higher levels of education, better ix occupation, etc.). Similar applies to the state sector workers when compared to workers in the state-owned enterprises. Results also reveal that the main reasons behind the public sector wage premium are higher returns for education, work experience and some occupations, while higher ceteris paribus wages in state-owned enterprises, compared to the state sector, are the consequence of the factors that we cannot observe in the data. The results of the quantile regression indicate that the public sector wage premium in Serbia in 2014 was different at different levels of wage distribution. The premium at the bottom of the wage distribution (21% on the 10th percentile) was higher than at the median (16.9%), or at the highest wages (12.4%). Due to these differences, and exempt of the wages lower than 25,000 RSD were from the reduction, the second hypothesis examined whether the reduction in the public sector wage premium in 2015 and 2016 was different at different levels of wage distribution. This hypothesis was also confirmed: the results of quantile regression indicate that premium changes were not significant at low wages, while the reduction of the premium was significant from the 30 percentile onwards, being most pronounced at the top of the wage distribution. Within this hypothesis, we also analysed different effects of the fiscal consolidation on the public sector subsectors. The analysis indicates two important findings. Firstly, the in 2014 state sector wage premium (compared to the private sector) had a theoretically expected pattern: high premium at the bottom and low premium at the top of the wage distribution, while in state-owned enterprises the wage premium was constant across the wage distribution. Due to this trend, from median to the highest wages, the premium is higher for the state-owned enterprises than for the state sector. Secondly, the comparison of the results between 2014 and 2015 indicates that the reduction in the wage premium in the state sector was significant at all levels of the wage distribution (except at the very bottom), while in the state-owned enterprises, the reduction of the premium was significant only for high wages. Additionally, the premium drop was significantly higher in the state sector than in the state-owned enterprises at all parts of the wage distribution. These results, together with the results within the previous hypothesis, indicate that the mechanisms and factors that influence the wage setting, as well as the responses to fiscal consolidation are different in the public sector subsectors. x The third hypothesis investigated whether the fiscal consolidation also caused structural effects on the labour market. According to this hypothesis, the public sector, due to the wage reduction, becomes a less attractive option for workers, who can decide to move to the private sector, or to withdraw to inactivity. Direct examination of the effects of wage cut through panel analysis indicated that this hypothesis was not confirmed, and that the effects of fiscal consolidation did not increase the likelihood of workers' transition to the private sector or inactivity. Finally, within the fourth hypothesis, we examined whether the reduction in public sector wages, as a result of fiscal consolidation, also affected the wages in the private sector. Investigation of the relationship between wages in the public administration and the manufacturing sectors, as representatives of public and private sector respectively, indicated that the wages in the two sectors are cointegrated, i.e. that they have a long- term equilibrium. However, the results of the VAR and error correction model indicate that wages in the manufacturing sector affect earnings in the government sector, while the causal relationship in the opposite direction cannot be identified. In other words, the fourth hypothesis was not confirmed: the fiscal consolidation had no effect on the private sector wages, since they are not affected by either short-term or long-term changes of the public sector wages.

Upravljanje ljudskim resursima u međunarodnom poslovanju i marketingu : strateški pristup

Human resources management in international business and marketing : strategic approach

Značaj upravljanja ljudskim resursima u međunarodnom menadžmentu i marketingu je signifikantno povećan tokom poslednje dve dekade XX veka. Sa globalizacijom i ekspanzijom kvaliteta, kao i težnjom ka ostvarivanju maksimalne produktivnosti uz minimalne troškove, ljudski resursi su zauzeli centralno mesto u strateškom poslovanju. Obrazovanje i obuka, veštine, stil, performanse i osposobljenost zaposlenih, usklađeni sa potrebama kompanije, predstavljaju značajne faktore obezbeđivanja konkurentne prednosti na tržištu. Samo lojalni zaposleni mogu da utiču na stvaranje kritične mase lojalnih potrošača. Termin "ljudski resursi" je nastao u vremenu između dva svetska rata. Popularisan je posle 1945. u Americi i potisnuo je "industrijske odnose", "organizaciono ponašanje" i druge, ranije korišćene termine. Iz njega su kasnije izvedeni i drugi pojmovi, kao što su "orijentacija ka ljudima", ili "osposobljavanje ljudi". Osnovna pretpostavka savremene teorije koja privlači veliki broj istraživača i praktičara ljudskih resursa, je postulat da su ljudi i organizacija potrebni jedni drugima. Organizaciji su potrebne ideje, energija i talenat, dok su pojedincima neophodni mogućnost rada, karijera i primanja. Drugim rečima, organizacija treba da služi ljudskim potrebama. Dobra sprega pojedinaca i organizacije koristi obema stranama: ljudi ostvaruju potrebu za radom, što vodi satisfakciji zaposlenih, a organizacija dobija ljudski talenat i znanje koji su joj neophodni. U uslovima timskog rada, strateških alijansi, partnerskih aranžmana i mrežnih organizacija, formiran je novi model ljudskih resursa sa globalnim atributima, zasnovan na novim tehnologijama i naprednim principima dizajna rada. U tom kontekstu definisani su osnovni ciljevi strateškog međunarodnog menadžmenta ljudskih resursa: konkurentnost, profitabilnost, efikasnost i fleksibilnost radne snage u globalnom okruženju.

The importance of human resources management in international management and marketing has increased significantly during the last two decades of 20th century. Along with the processes of globalization and quality expansion, as well as tendency towards achieving the highest productivity with lowest costs, the role of human potentials took the central position in strategic business. Education and training of employees, their skills, style, performances and qualifications, harmonized with company needs, are one of the most important factors of competitive advantage assurance at the market. Only loyal employees can induce the critical mass of loyal customers. The term "human resources" was created in the period between World War I and II. Its main diffusion came in USA after 1945, replacing the "organizational behaviour", "industrial relationships" and other frequently used terms. Under the name of human resources management, disciplines like "people empowerment" and "orientation towards people" evolved later. A basic assumption of the current theory that intrigues both researchers and practitioners of human resources, is a postulate that people and organization need each other an organization requires ideas, energy and talents, but individuals need their work possibilities, careers and earnings. In other terms, organization should serve individual needs. A good association of individuals and organization benefits both sides: people can achieve work, which leads to satisfaction of employees; in turn, organization gains human talents and knowledge it needs. With teamwork, strategic alliances, partner arrangements and network organizations in background, a new model of human resources with global attributes emerged, based on new technologies and advanced principles of work design. In that framework, the principal objectives of strategic international human resources management are defined as competitiveness, profitability, efficiency and flexibility of workforce in global environment.

Detection and localization of damage of civil structures based on ambient vibraton measurements

Detekcija i lokalizacija oštećenja građevinskih konstrukcija na osnovu registrovanih ambijentalnih vibracija

Općenito, u radu je razmatrana detekcija oštećenja različitih tipova čeličnih konstrukcija. Oštećenje se moţe otkriti na različite načine, koji zavise od različitih postupaka navedenih u literaturi. Detekcija oštećenja zavisi od postupka poredjenja između aţuriranih modalnih parametara (prirodnih frekvencija i oblika) modela KE s odgovarajućim eksperimentalnim vrednostima. Procenjuju se modalni strukturni parametari, eksperimentalno i numerički. Na osnovu merenja ambijentalnih vibracija (MAV), na različitim vrstama čeličnih konstrukcija, eksperimentalni modalni parametri se određuju pomoću ARTeMIS softvera u skladu s tehnikom frekvencijskog razlaganja (FR). S druge strane, primenom ANSYS softvera, izračunavaju se numeričke vrednosti modalnih parametara potrebnih u postupku otkrivanja oštećenja. Detekcija oštećenja vrši se uz pomoć predloţene Tabu (TS) optimizacije za otkrivanje lokacije i ozbiljnost oštećenja. Tehnika TS optimizacije je relativno nova i nije ranije korišćena u detekciji oštećenja gradjevinsk ih konstrukcija. Predloţene procedure TS optimizacije su napisane i izvedene u MATLAB okruţenju. MATLAB ima sposobnost za istovremeno razmatranje eksperimentalno dobijenih parametara modela, i odgovarajućih numeričkih vrednosti koje se kontunualno aţuriraju uz pomoć ANSYS softvera. Poređenje između procenjenih eksperimentalnih i numeričkih parametara modela se vrši u skladu s vrednostima dobijenih predloţenom "objektivnom funkcijom" (treba "funkcija kriterijuma" ili "funkcija cilja") koja određuju vrednost greške. Minimalna vrednost greške odraţava optimalnu vrednost koja ukazuje na najbliţi rezultat ciljne (stvarne) vrednosti. U cilju detekcije oštećenja usvojen je još jedan vaţan korak, tj. kalibracija s aţuriranjem FE modela. Iz više razloga, neslaganje između modalnih parametara eksperimentalnog i numeričkog modela je obično dovodi do pogrešnih rezultata u postupku otkrivanja oštećenja. Stoga, proces kalibracije ima za cilj da proizvede (aţurira) numeričke vrednosti strukturnih parametara modela, što je moguće bliţe , odgovarajućim eksperimentalnim vrednostima. Na ovaj način je ostvarena konvergencija između odnosa modalnih parametara, što omogućava postupak detekcije oštećenja. Modelirane su četiri vrste čeličnih konstrukcija kako bi se proučavalo ponašanje 1D, 2D i 3D konstruktivnih modela u toku procesa kalibracije i detekcije oštećenja . Model slobodno oslonjene grede s prepustima je usvojen za proučavanje ponašanja 1D modela, dok model rešetke se koristi za predstavljanje 2D modela. Za 3D model, usvojena su dva modela: Vierendeel model mosta i model 10-spratne zgrade. Ovo potvrđuje sposobnost primene predloţene procedure , kalibracije FE modela aţuriranja i detekcije oštećenja na sloţene konstrukcije. Predstavljena studija otkrila je da je predloţeni postupak TS optimizacije efikasna i snaţna tehnika za korišćenje u obe oblasti kalibracije FE modela aţuriranja i detekcije oštećenja sloţenih građevinskih objekata.

Generally, damage detection of different types of steel structures is the main aspect that has been studied in the present work. Damage could be detected by different ways which depend on different procedures existed in literature. In the present work, the adopted concept of damage detection depends on the procedure of comparison between the updated modal parameters (natural frequencies and mode shapes) of the FE model with their corresponding experimental values. Hence, estimating of structural modal parameters experimentally and numerically are another aspects that are adopted in the present work. Based on ambient vibration measurements (AVM) that implemented upon different types of steel structures, experimental modal parameters are extracted using ARTeMIS software according to the frequency domain decomposition (FDD) technique. On the other hand, modal analysis by ANSYS software is implemented to compute the numerical values of modal parameters which required during the procedure of damage detection. The process of damage detection is executed with the aid of proposed Tabu Search (TS) optimization procedure to detect the location and severity of damage. This technique is relatively new and was not used before in the field of civil structure damage detection which satisfies the state of the art in the present work. The proposed procedures of TS optimization are written and performed in MATLAB environment. MATLAB has the ability of simultaneously handling the experimentally extracted modal parameters with their corresponding numerical values which are continuously updated by ANSYS software. The comparison between the estimated experimental and numerical modal parameters is executed according to values obtained by a certain proposed form called "objective function" which produces the value of error that used in the comparison. Minimum value of error reflects the optimum value that indicates the closest result to the target (actual) value. For the sake of damage detection, another important aspect had been adopted in the present work which is the calibration process by updating of FE model. Due to several reasons, mismatch between modal parameters of the experimental and numerical model is usually exist leading to erroneous results in the procedure of damage detection. Hence, calibration process is aimed to produce numerical (updated) values of structural modal parameters as close as possible to their corresponding experimental values. In this way, the convergence between the compared modal parameters is achieved which allows the procedure of damage detection to be implemented with more accurate results. Four types of steel structures are modeled in the present work to study the behavior of 1D, 2D and 3D structural models during the procedures of calibration process and damage detection . A simply supported overhang beam model is adopted to study the behavior of 1D structural model while a grid-bridge model has plate action is used to represent 2D structural model in the proposed procedures. For the 3D structural model, two models are adopted: Vierendeel bridge model and 10-storey building model which represent the most complex structural models in the present work. This verifies the ability of applying the proposed procedures, calibration by FE model updating and damage detection, upon the complex structures. Present study discovered that the proposed TS optimization procedure is an efficient and robust technique for using in the both fields of calibration by FE model updating and damage detection of complex civil structures.

Nodalni centri Topličkog okruga

The nodal centres of Toplica district

Istraživanje u ovom radu fokusirano je na prostorno-funkcijski uticaj centralnih naselja, kao nosilaca održivog razvoja Topličkog okruga na transformaciju prostora u njihovom okruženju. Savremeni procesi industrijalizacije, urbanizacije, deagrarizacije, polarizacije i globalizacije doprinose pored socio-ekonomskog preobražaja posmatranog prostora i stvaranju novih nosilaca funkcionalnih odnosa u prostoru. U prvom delu rada prikazan je teorijsko-metodološki pristup i objašnjenja vezana za nastanak, evoluciju i genezu naseljenih mesta, kao i istorijat proučavanja posmatranog problema. Stvaranje prvih gradova i različite teorije o njihovom poreklu možemo sagledati kroz različite periode u prošlosti. Evolucija gradova prvobitno zasnovana na duhovnim funkcijama uz veliki uticaj ekonomsko-socijalnih delatnosti, preko mnogobrojnih neagrarnih funkcija koji čine osnovni sadržaj urbanih centara, doprinosi razvoju gravitacionih i centralnih funkcija naseljenih mesta. Gradovi svojim uticajem „oplemenjuju“ mrežu okolnih naselja, jačaju međusobne odnose naselja i centara i stvaraju tako čitav funkcionalni sistem naselja jednog područja, odnosno gravitacionog urbanog jezgra. Podelom funkcija na primarne, sekundarne i tercijarno-kvartarne, stvara se osnova i tipologija naselja po funkcionalnom kriterijumu prema vrsti delatnosti i osnovnih privrednih i vanprivrednih sadržaja u njima. Geografski položaj Topličkog okruga, kao i opština u Topličkom okrugu sa opštinskim gravitacionim centrima predstavljaju vrlo interesantan prostor za istraživanje. Međusobni uticaji raznovrsnih funkcija, prirodnih potencijala i osobenosti, vertikalne i horizontalne raščlanjenosti geomorfoloških oblika, vrlo složene i heterogene demografske slike i stvorene mreže naselja, predstavljaju vrlo kompleksan prostor, odnosno sistem naselja kao model i metodološku osnovu za dalja proučavanja ili planiranja budućeg razvoja mreže naselja Topličkog okruga. U radu se kroz prizmu teorijsko-metodoloških postavki ogleda stvaranje jednog vrlo osobenog sistema naselja u konkretnim uslovima. Analizom dostignuća i rezultata o posmatranom problemu kroz rad se vrlo jasno ističu razvojni potencijali naselja, kako bi se odredili budući pravci daljeg razvoja opština i mreže naselja Topličkog okruga. Očekivani rezultat i doprinos ovih istraživanja može se označiti jedino kroz celovito sagledavanje funkcijskog razvoja nodalnih centara i njihovog uticaja na socio- ekonomsku transformaciju ostalih naselja. Zamisao rada je da se prostor Toplice, kao složena naseljska celina, prikaže u svetlu društveno-ekonomskog razvoja i kao osnova daljeg privrednog razvoja ovog dela Republike Srbije. Posmatrani vremenski period obuhvaćen radom je od 1981. godine do poslednjeg popisa 2011. godine, s obzirom na to da su se baš u ovom periodu desile veoma značajne promene u ukupnom društveno-ekonomskom poretku zemlje. U pojedinim delovima rada korišćeni su podaci ranijih popisa u cilju što potpunijeg kvantitativnog poređenja različitih segmenata društvene sfere. Analitičkim pristupom izvršena je analiza prostorne strukture i organizacije nodalnih i ostalih naselja, valorizacijom složenih međusobnih odnosa unutar naseobinskih struktura, a primenom kvantitativnih i kvalitativnih metoda potvrđeni su polarizacioni i podsticajni efekti centara u transformaciji naselja u gravitacionom okruženju. Shodno postavljenom problemskom zadatku može se izvesti zaključak da je prostorni razvoj sistema naselja zasnovan na gravitaciono-podsticajnim i polarizacionim odnosima i uticaju nodalnih centara, što predstavlja temelj za njihovo geoprostorno planiranje, uređenje i održivi razvoj. Dobra funkcionalna povezanost i integracija primarnog i ostalih nodalnih centara i njihovog okruženja, doprinosi formiranju i razvoju svih naselja Topličkog okruga.

Research in this study is focused on spatial-functional impact of central settlements as the carrier of sustainable development of the Toplica District, on the transformation of the space in their environment. Contemporary processes of industralization, urbanization, deagrarianization, the polarization and globalization contribute socio-economic transformation of the observed space as well as the creation of new carrier of functional relationships in space. The basic part of the study includes the theoretical and methodological approach and explanations of the origin, evolution and genesis of settlements, as well as the history of studying the observed problems. The creation of the first cities and the different theories about their origins go back very far into the past. The evolution of cities originally designed to function with great spiritual impact of economic and social activities through a number of non-agrarian functions that constitute the main content of the urban centers of gravity, contributes to the development of the central functions of settlements. Towns with its own influences enrich the network of surrounding settlements, strengthen their mutual relations and create a whole functional settlement system of one area , or the gravity of the urban core. By dividing the functions of the primary, secondary and tertiary, the basis and types of settlements are created by functional criteria according to the type of economic activity and the primary content in them. Geographic location of the Toplica District, and municipalities in Toplica with municipal centers of gravity are very interesting area to explore. Interaction of various functions, and characteristics of natural resources, vertical and horizontal separations of geomorphological forms, is very complex and heterogeneous demographic picture and created a network of settlements, represents a space, or settlement system as a model and methodological basis for further studies and perspectives, or planning the future development of the network of settlements in the municipalities of Toplica region. The study, through the prism of theoretical and methodological principles, reflects the creation of a very distinctive system of settlements in the concrete conditions. The analysis of the achievements and results of the observed problem through the work very clearly point out development potentials of the settlements, in order to determine future directions for further development of the municipality and future network of settlements of the Toplica District. A comprehensive overview of the functional development of nodal centers and their impact on the socio-economic transformation of other settlements can represent the basic expected result and contribution of this research. The idea behind the study is for the geographically complex area to be displayed in the light of socio-economic development, and as a basis for further economic development of this part of the Republic of Serbia. The observed time frame of the study indicates the period from 1981 to the last census in 2011, considering that in this period very significant changes in the overall socio-economic order of the country occurred in this period. In some parts of the study, the data of previous census have been used in order to provide fuller quantitative comparison between different segments of the social sphere. An analysis of the spatial organization of nodal and other settlements has been made using analytical approach, by valorization of complex mutual relations within the settlement structure and the application of quantitative and qualitative functional connections in the monitored area. According to the previously stated problem-oriented approach, it can be concluded that the sustainable development of the system of settlements based on the gravity-motivative and polarization effects of nodal settlements′ influence; the settlement- functional concentration and the development of other settlements stems from the process of redistribution within the active population. An excellent functional connectivity and integration of nodal center and the environment, contributes to the formation and development of all settlements of Toplica.

Modeliranje gustine zemljine kore pri rešavanju problema graničnih vrednosti potencijala zemljine teže

Modeling of the earth crust density in solving the boundary value problems of the gravity potential

Doktorska disertacija posvećena je modeliranju gustina Zemljine kore u postupku određivanja gravitacionog uticaja topografskih masa na anomalijski potencijal i njegove funkcionale na teritoriji Republike Srbije. Gravitacioni uticaji topografskih masa određeni su na osnovu podataka digitalnog modela terena na teritoriji Srbije i globalnog modela terena SRTM (Shuttle Radar Topography Mission) za uticaje topografskih masa van granica Srbije. Saglasno raspoloživim i relevantnim podacima kreiran je digitalni model gustina do geoida, dok je topografskim masama van granica Srbije dodenjena vrednost konstantne gustine   .2 67 g/cm 3 . Sve topografske mase podeljene su na prave prizme pravougaone osnove, a za modeliranje njihovog gravitacionog uticaja primenjena su dva postupka: klasična terenska korekcija i rezidualni model terena. Modeliranje uticaja topografskih masa urađeno je sa:  gustinama iz digitalnog modela gustina i  konstantnom gustinom,   .2 67 g/cm 3 . Analizom dobijenih rezultata, pokazano je da uticaj gustina topografskih masa nije zanemarljiv u postupku rešavanja graničnih problema potencijala Zemljine teže, a posebno pri određivanju geoida centimetarske tačnosti.

The doctoral dissertation is dedicated to density modelling of the Earth crust while determining the gravity effects of topographic masses to the anomaly potential and its functionals at the territory of Republic of Serbia. The gravity effects of topographic masses are determined on the basis of the digital terrain model data at the territory of Republic of Serbia and the global terrain model SRTM (Shuttle Radar Topography Mission) for topography masses influences out of Serbia borders. In concordance with available and relevant data a digital terrain model with the density down to the geoid was created, whilst the topographic masses out of Serbia borders were given the value of a constant density   .2 67 g/cm 3 . All topographic masses were divided in right prisms with rectangular base and for modelling their gravity effects there were two methods that were applied: classic terrain correction and residual terrain model. Topographic masses influence modelling was done with:  densities out of digital model and  constant density,   .2 67 g/cm 3 . By analyzing of gained results, it was shown that the effects of topographic masses densities is not irrelevant in the procedure of solving the boundary value problems of gravity potential, especially while determining geoid of centimeters precision.

Metodologija izbora optimalne veličine osnovne zone bilansiranja (OZB) u vodovodnim sistemima

Methodology for the selection of optimum size of district metered areas (DMA) in water distribution systems

Prethodnih decenija je prepoznata opasnost od ugrožavanja vodnog resursa. Paralelno sa tim, gotovo u svim evropskim zemljama, specifiĉna potrošnja vode je imala trend porasta. Povećanje potrošnje vode po glavi stanovnika, je najprije posljedica povećanja gubitaka u vodovodnim sistemima. Poznato je da se gubici vode iz sistema za snabdijevanje ne mogu potpuno eliminisati, ali se mogu kontrolisati. Podjelom vodovodnog sistema na zone znatno se olakšava posao kontrole gubitaka. Opšte prihvaćen naziv za te zone je "District Metered Areas" (DMA), tj osnovne zone bilansiranja (OZB). Osnovna zona bilansiranja je definisana kao zasebna oblast vodovodnog sistema, obiĉno kreirana zatvaranjem zatvaraĉa ili potpunim prekidom cjevovoda, koja ima svoj ulaz i izlaz. U zoni se mjeri koliĉina vode koja ulazi i izlazi iz te oblasti. Dekompozija vodovodnog sistema na osnovne zone bilansiranja nije ni malo jednostavan zadatak, jer zavisi od više faktora. Faktori koji utiĉu na veliĉinu osnovne zone bilansiranja su tehniĉke i ekonomske prirode. Kontrola pritiska je važan tehniĉki faktor u procesu smanjenja gubitaka. Upravljanje pritiskom je danas priznato kao jedna od najisplativijih metoda za smanjenje gubitaka vodovodnih sistema. Ekonomski faktori su najĉešće odluĉujući u procesu formiranja OZB. Pravilna analiza ekonomskih faktora, koji prate dekompoziciju sistema na OZB je presudni ĉinilac, na osnovu kojeg se preduzeća koja upravljaju vodovodnim sistemima odluĉuju na korak zoniranja sistema. Osim faktora tehniĉke i ekonomske prirode, sociološki faktori su prepoznati kao važni u procesu podjele sistema na zone. Pod sociološkim faktorima se podrazumjeva uticaj društvene zajednice na važnost rada na smanjenju gubitaka u vodovodnim sistemima. Obzirom na dosadašnju praksu, pojavila se potreba da se uticaji navedenih faktora objedine u jedinstvenu metodologiju, koja će preciznije definisati postupak odreĊivanja optimalne veliĉine OZB. Predmet istraživanja, koje je sprovedeno u ovom radu, je analiza faktora koji utiĉu na izbor optimalne veliĉine OZB u vodovodnim sistemima. Analizirani su faktori tehniĉke i ekonomske prirode. Shodno toj analizi, definisana je metodologija izbora optimalne veliĉine OZB.

Drinking water supplies have been seriously endangered over the recent decades. In parallel, specific water consumption per capita has grown in almost every country. The significant increase of water consumption per capita predominantly occurs as a result of the increase of water loss in distribution systems. It is well known that water losses from the supply systems cannot be eliminated. However, they can be controlled. Decomposition of water distribution networks into areas enables better water loss management. The generally accepted term for the areas is “District Metered Areas“ (DMAs). District Metered Area is defined as a separate part of the water supply system, normally created by closing the valve or by a complete break of the pipeline, which has its entry and exit point. In the area the quantity of water coming in and out is measured. Decomposition of water supply systems into district metered areas is not a simple task as it depends on a number of factors. The factors influencing the size of district metered areas are grouped into technical and economic ones. Pressure control represents a relevant technical component in the process of water loss reduction. Nowadays pressure management has been recognized as one of the most economical methods for water loss reduction in distribution systems. Economic factors usually play the most crucial role in creating DMAs. The proper analysis of economic factors, associated with the decomposition of the system into DMAs, is of high importance, depending on which water companies decide upon the district metering. Apart from the technical and economic factors, social factors have been emphasized as significant in the process of dividing the distribution system into areas. The social factors refer to the influence of social community on the very water loss reduction in the distribution systems. According to the former practice, a need to consolidate the impacts of the stated factors into a unique methodology has emerged. The aim of the methodology would be to define more precisely the procedure of determining the optimum size of DMAs. The subject of the research, conducted in this paper, is the analysis of the factors influencing the selection of the optimum size of DMAs in water supply systems. The technical and economic factors are examined. According to the analysis, the methodology concerning the selection of the optimum size of DMAs is defined.

Modeliranje emisije zagađenja kišnog oticaja sa urbanih slivova

Modeling of pollution emissions from urban cathments

U cilju istraživanja procesa emisije zagađenja sa urbanih slivova u okviru ove disertacije izvršena je teorijska i eksperimetalna analiza i modeliranje kišnog oticaja sa eksperimentalnog sliva koji je formiran u dvorištu Građevinskog fakulteta Univerziteta u Beogradu. Sliv pokriva preko 3300 m2, od čega skoro dve trećine su nepropusne površine. Metodom mokrog usisavanja su izvršene serije zahvatanja uzoraka sa nepropusnih površina sliva, u cilju određivanja akumulisanja i priraštaja zagađenja na površinama od asfalta (saobraćajne površine), betona (trotoar namenjen pešacima) i kamena (nije u direktnom kontaktu sa bilo kojim vidom saobraćaja). U zahvaćenim uzorcima su određivani pH, elektroprovodljivost, suvi ostatak, suspendovane materije, hemijska potrošnja kiseonika, mutnoća, ukupni azot i fosfor, katjoni i teški metali, a u nekim uzorcima i organska jedinjenja. Deo uzoraka je podvrgnut separaciji čvrste i tečne faze, određen je granulometrijski sastav izdvojene čvrste faze i sadržaj zagađenja u svakoj granulometrijskoj frakciji. Zatim su frakcije čvrstih čestica ispitivane savremenim analitičkim metodama karakterizacije u cilju definisanja njihove specifične površine, veličine i zapremine pora, karakteristika i sastava površina čestica i mineraloškog sastava. Ispitivanja akumulisanja zagađenja su ukazala da postoji trend usporavanja akumulisanja zagađenja tokom vremena, odnosno da masa zagađenja po jedinici nepropusne površine teži zasićenju. Najveća masa zagađenja je izmerena na asfaltnim površinama, zatim na betonu a najmanja na kamenu. Ovo ukazuje na to da je akumulisanje zagađenja veće na površinama sa većom hrapavošću. Od ispitivanih povšina, površine pod direktnim uticajem motornog saobraćaja imaju najveću akumulaciju zagađenja. Izvršena je detaljna analiza merenih podataka u cilju modeliranja akumulisanja i priraštaja zagađenja na nepropusnim površinama. Pored već poznatih i korišćenih funkcija, ispitani su i novi oblici funkcija koje su pokazale dobro prilagođavanje mernim rezultatima. Poredeći dobijene rezultate u pogledu mase akumulisanih materija po jedinici površine sa rezultatima drugih istraživanja datih u literaturi, može se zaključiti da je akumulisanje zagađenja na ispitanom eksperimentalnom slivu znatno veće nego na drugim lokacijama, što je posledica odsustva redovnog održavanja i čišćenja. Rezultati ispitivanja ukazuju da su dnevni priraštaji zagađenja na površinama ispitanog sliva znatno veće u letnjim meseima nego u jesen. Pri tome su dnevni priraštaji zagađenja na asfaltu znatno veći nego na betonu, a najmanji su na kamenu, što je u skladu sa načinom korišćenja ovih površina. ii Utvrđena je veoma dobra korelacija između pojedinih parametara kvaliteta: mutnoća, suvi ostatak i supendovane materije su u dobroj korelaciji. Mutnoća i suspendovane materije su takođe dobro korelisani sa hemijskom potrošnjom kiseonika, ukupnim fosforom, sadržajem teških metala i sulfatima. S obzirom na jednostavan način merenja suspendovanih materija i mutnoće, oni su predloženi za parametre preko kojih bi se procenjivalo zagađenje kišnog oticaja sa eksperimentalnog sliva u realnom vremenu. Takođe u diseraciji je pokazano da se preko suspendovanih materija može uspešno modelirati emisija niza drugih parametara zagađenja sa sliva. Analiza glavnih komponenti (PCM) ukazuje na to da se rezultati merenja grupišu u odnosu na tip povšine, što ukazuje na specifičnosti zagađenja izdvojenih na pojedinim površinama. Ispitivanja su ukazala na znatno više koncentracije svih zagađenja u sitnijim frakcijama čvrstih čestica, uz veoma dobro razdvajanje čvrste i tečne (rastvorene) faze teških metala u uzorcima. Ispitivane čvrste čestice su makroporozni prirodni materijali niske specifične površine, pa je zaključeno da bi glavni uzrok dobrog razdvajanja čvrste i rastvorene faze teških metala u ispitivanim uzorcima mogao biti proces taloženja. Za potrebe modeliranja procesa padavine-oticaj, akumulisanja, pokretanja i transporta zagađenja sa eksperimetalnog sliva, razvijena su dva modela: (a) 1,5D model površinskog tečenja sa detaljnom mrežom površinskih kanala i nizom slivnih površina u skladu sa digitalnim modelom terena sliva, i (b) uprošćeni model sliva gde je površinsko tečenje sa sliva shematizovano preko osam slivnih povšina i isto toliko površinskih kanala. Modeliranje je urađeno u okruženju programskog paketa EPA SWMM. Modeliranje akumulisanja i spiranja zagađenja izvršeno je korišćenjem zavisnosti dobijenih eksperimentalnim ispitivanjima, a transport zagađenja po površini terena, do ulaska u kanalizaciju, je modeliran metodom dinamičkog talasa. Rezultati ukazuju da je 1,5D modelom moguće uspešno modelirati površinski oticaj i spiranje zagađenja, uključujući procese transporta dominantnim pravcima i lokalna zadržavanja vode i zagađenja na površini terena. Uprošćeni model može sa prihvatljivom tačnošću modelirati ukupnu emisiju zagađenja, uz znatno kraće trajanje proračuna u odnosu na 1,5D model.

An experimental catchment was established on the grounds of the University of Belgrade - Faculty of Civil Engineering. Theoretical and experimental rainfall-runoff analysis and modelling were performed in an experimental catchment within the framework of this thesis for the purpose of conducting research on pollution emissions from urban catchments. The experimental catchment covers an area of over 3300 m2, of which almost two thirds are comprised of impervious surfaces. Using the wet vacuum sweeping method, a series of samples were taken from the impervious catchment surfaces in order to determine pollution build-up and accumulation rates on asphalt (road surfaces), concrete (pedestrian walkways) and stone (not in direct contact with any type of traffic) surfaces. The samples were analysed for pH, conductivity, total solids, total suspended solids, chemical oxygen demand, turbidity, total nitrogen, total phosphorus, cations and heavy metals, while some samples were analysed for specific organic compounds. A portion of the samples was subjected to liquid-solid phase separation where the grain size distribution of the separated solids and pollutant content in each particle size fraction were determined. Solid particle fractions were then tested using advanced analytical characterization techniques to determine their composition, specific surface area, pore volume and size, surface characteristics and composition, and mineralogical composition. Pollution build-up analysis has shown that there is a gradual decrease in pollution build-up on impervious surfaces over time, when the mass of pollution per unit of surface area approaches saturation point. The greatest amount of accumulated pollution was measured on asphalt, followed by concrete and finally, the lowest amount was detected on stone surfaces. This indicates that accumulation was greater on surfaces with higher roughness. Among the investigated surfaces, the highest contaminant accumulation was detected on surfaces directly exposed to motor vehicle traffic. A detailed analysis of the measured data was conducted for the purpose of modelling of pollution build-up on impervious surfaces using previously known and tested equations alongside new equations, which have shown a good fit to the measured results. By comparing the surface results of contaminant accumulation with the results of other studies presented in the literature, it can be concluded that pollution accumulation in the investigated experimental catchment in Belgrade is significantly greater than at other locations, which may be attributed to a lack of regular maintenance and cleaning. Investigation results indicate that the daily pollution build-up rate on the examined catchment surface is significantly higher in summer than in autumn. In addition, the daily pollution build-up rate on asphalt is significantly higher than on concrete, while stone had the lowest rate, which is consistent with the type of surface use. iv A good correlation was found between turbidity, total solids and total suspended solids. Turbidity and suspended solids are also well correlated with chemical oxygen demand, total phosphorus, heavy metal content and sulphates. Therefore these parameters have been proposed as surrogate parameters for the assessment of runoff pollution loads from the experimental catchment in real time. Additionally, the conducted research has proven that suspended solids can be used as a surrogate parameter for modelling of emissions of other pollutants from the catchment with reasonable accuracy. Principal component analysis (PCA) reveals the grouping of the measurement results according to the surface type, indicating the specificity of pollution on certain types of surfaces, which should be further explored. Tests have determined significantly higher concentrations of pollution in finer particle size fractions, with a strong partition between the solid and liquid phases of heavy metals in all samples. The examined solid particles were macro porous natural materials with a low specific surface area, and it was concluded that precipitation was the phenomenon responsible for good partitioning of the solid and liquid phase of heavy metals in the analyzed samples. For analyses of rainfall-runoff, build-up, wash-off and pollution transport on the experimental catchment, two models have been developed: (a) 1.5D surface runoff flow model with a detailed surface channel network and a number of catchment areas in accordance with a digital terrain model of the catchment, and (b) a simplified model of the catchment with a total of eight subcatchments and surface channels as conduits. The modelling was done in the EPA SWMM software package environment. Modelling of pollution build-up and wash-off was performed using the build-up and wash-off functions obtained in the investigation of the samples taken from impervious surfaces within the catchment. Surface runoff flow was modelled using the dynamic wave method. The results indicated that the 1.5D model can successfully predict surface runoff and pollutant wash- off, including surface flow along routes with the highest slopes and local surface retention of water and pollutants. The simplified model can, with reasonable accuracy, assess the total emission of pollution from the catchment, in a much shorter computational time compared to the 1.5D model.

Nelinearna statička i dinamička seizmička analiza okvirnih zgrada prema performansama

Performance -based nonlinear static and dynamic seismic analysis of framework buildings

U ovoj doktorskoj disertaciji su sprovedena istraživanja 2D i 3D modela okvirnih sistema zgrada prema performansama za uslove seizmičkog dejstva, a u skladu sa PBEE (Performance-Based Earthquake Engineering) metodologijom. Istraživanja se mogu klasifikovati u četiri bitno različite celine: istraživanja na polju akcelerograma i spektara odgovora, istraživanja na polju nelinearnog odgovora 2D modela okvirnih sistema koji participiranju u konstruktivnom sistemu okvirnih zgrada (dekomponovani ili tretirani kao nezavisne celine), istraživanja na polju nelinearnog odgovora 3D modela okvirnih zgrada i istraživanja na polju odnosa kapacitet konstrukcije/seizmički zahtev 2D i 3D modela okvirnih zgrada. Istraživanja na polju akcelerograma zasnivaju se na primeni akcelerograma realnih zemljotresa i akcelerograma veštačkih zemljotresa. Prethodno su dvokomponentalni akcelerogrami realnih zemljotresa selektovani i preuzeti iz PEER GMDB baze. Veštački akcelerogrami su razmatrani kao nepotpuni i potpuni nestacionarni veštački akcelerogrami, pri čemu je pri kreiranju potpunih nestacionarnih veštačkih akcelerograma uzeta u obzir i analiza seizmičkog hazarda. Procesiranje akcelerograma je sprovedeno po teoriji signala kroz analize: formatiranje, konvertovanje, skaliranje, kalkulacija, procesiranje, kompatibilizacija, filtriranje, generisanje i transformacija. Postupak generisanja međukomponenata akcelerograma po uglovima je sproveden rotacijom komponenata akcelerograma u pravcu raseda i upravno na pravac raseda. Integracijom međukomponenata akcelerograma kreirana je površ akcelerograma (ground motion record surface). Na osnovu generisanih međukomponenata akcelerograma razvijeni su spektri odgovora i integrisani u površ spektra odgovora (response spectra surface). Za sve akcelerograme i spektre odgovora su analizirane mere intenziteta i kreirane anvelope mere intenziteta (intensity measure envelope). Istraživanjem su razmatrani aspekti skaliranja i kompatibilizacije akcelerograma i njihov uticaj na formu površi spektra odgovora. Istraživanja na polju nelinearnog odgovora 2D modela okvirnih sistema zasnivaju se na primeni linijskih konačnih elemenata, čiji je poprečni presek diskretizovan na vlakna i kod kojih se uzimaju u obzir razvoj neelastičnih deformacija. Definisani su opšti modeli pushover krivih koji su poslužili kao podloga za dalja razmatranja u doktorskoj disertaciji: visoko duktilno, visoko ili srednje duktilno, nisko ili neduktilno ponašanje zgrada i prelazna kategorija. Takođe, sprovedena je i klasifikacija pushover krivih varijacijom duktilnosti, duktilnosti u zoni ojačanja/omekšanja i koeficijenta odnosa krutosti u nelinearnom i linearnom domenu. Primenom ova tri parametra generisan je set tipoloških modela pushover krivih kod okvirnih 2D i 3D modela zgrada. Istraživanje tipa raspodele lateralnog seizmičkog opterećenja kod NSPA pushover analize sprovedeno je razmatranjem rešenja dobijenih iz INDA analiza zemljotresa. Predložena je parabolična raspodela kao alternativa ravnomernoj i ekvivalentnoj. Prednost ovakve raspodele je dokazana upoređujući sa rešenjem dobijenim iz regresione analize za grupu zemljotresa, odnosno diskretne vrednosti INDA analiza. Takođe, istraživanjem je utvrđeno da se primenom pushover krive za ravnomernu raspodelu lateralnog seizmičkog opterećenja postiže dosta dobro pokrivanje INDA anvelope u kapacitativnom domenu. Istraživanje uticaja TU (total updating), IU (incremental updating) i HU (hybrid updating) korekcije je razmatrano na 2D modelu okvira, pri čemu se najkvalitetnija rešenja dobijaju primenom NSAPA-DBA analize, u odnosu na INDA analizu. U cilju određivanja potrebnog broja NDA analiza u okviru jedne INDA analize, razvijena je metoda koja se bazira na rešenju dobijenom iz NSPA analize. Sa druge strane, u cilju predikcije rešenja koje se dobija iz INDA analize 2D i 3D modela okvirnih zgrada sa mogućnošću razmatranja odgovora sistema u kapacitativnom domenu, a pri tome ne povećavajući znatnije vreme potrebno za procesiranje, razvijena je hibridna inkrementalna nelinearna statička-dinamička analiza (HINSDA - Hybrid Incremental Nonlinear Static-Dynamic Analysis). Istraživanjem su dobijene veće vrednosti driftova u slučaju primene PGA-IDRmax parametara, nego kod primene PGA-DR parametara. Najmanje odstupanje HINSDA krive od INDA krive dobija se primenom trećeg UBEPKHS konstitutivnog modela, dok se najveće odstupanje dobija primenom prvog UBEPKHS konstitutivnog modela. Istraživanja na polju nelinearnog odgovora 3D modela okvirnih sistema zasnivaju se na primeni linijskih konačnih elemenata, dok se na krajevima štapova apliciraju plastični zglobovi u kojima se omogućava razvoj nelinearnih deformacija. Efekti egzistencije tavanica modelirani su primenom elemenata veze. S obzirom da se kod 3D modela zgrada nelinearan odgovor razmatra primenom pushover krivih za različite uglove dejstva zemljotresa, to je integracijom istih dobijena pushover površ (pushover surface) za NSPA i za INDA (IDA) analizu. Razmatranjem je prikazan opšti model pushover površi i ukazano je na neke specifične modele pushover površi. Tipološki modeli NSPA pushover površi su definisani u funkciji varijacije duktilnosti, duktilnosti u zoni ojačanja/omekšanja i koeficijenta odnosa krutosti u nelinearnom i linearnom domenu za jedan i dva glavna pravca. Generalno razmatrajući identifikovane su četiri grupe pushover površi: rotaciono polisimetrične u osnovi, monosimetrične u osnovi, bisimetrične u osnovi i asimetrične u osnovi. Uvedenim koeficijentom površi duktilnosti (ductility area coefficient) moguće je analizirati performanse 3D modela zgrada uzimajući u obzir duktilnost za sve pravce, odnosno uglove dejstva zemljotresa. Istraživanjem je pokazano da INDA (IDA) pushover površ ima drugačiji oblik, u odnosu na NSPA pushover površi, s obzirom da je primenjena druga mera intenziteta i inženjerski parametar zahteva. U cilju analize performansi 4x6x3, 4x6x5-13, 15x4x4, 15x4x4-6 i 9x6x5-12 3D modela zgrada sproveden je monitoring razvoja plastičnih zglobova po inkrementalnim fazama, a koji je prezentovan preko izopovrši u polarnim koordinatama. Takođe, razmatrane su realizovane krive u polarnim koordinatama za driftove, relativnu vrednost ukupne smičuće sile u osnovi zgrade i duktilnost. Istraživanjem je utvrđeno da su kod svih modela zgrada realizovani manji ili nešto veći maksimalni globalni driftovi DRmax od globalnog drifta DRIO, za IO performansni nivo prema FEMA propisima. Kod zgrada veće spratnosti se lakše realizuje viša klasa duktilnosti, a da se povećanjem neregularnosti u osnovi ova duktilnost redukuje. Razmatrajući realizovane NSPA pushover površi u prostornim koordinatama utvrđeno je da je kod svih 3D modela zgrada krutost u nelinearnom domenu gotovo horizontalna Kn≈0 ili blago pozitivna, osim u pojedinim slučajevima, gde sa povećanjem nelinearnih deformacija krutost postaje negativna Kn<0. Kod 9x6x5-12 3D modela zgrade su realizovane znatno manje maksimalne relativne vrednosti ukupne smičuće sile, u odnosu na relativne vrednosti ukupne smičuće sile kod 4x6x3, 4x6x5-13, 15x4x4 i 15x4x4-6 3D modela zgrada, a što je direktna posledica proračuna seizmičkog dejstva prema SRP propisima. U odnosu na krive relativne vrednosti ukupne smičuće sile u osnovi zgrade (V/W)adeq za maksimalni globalni drift DRmax određene NSPA analizama koje su kružnog ili približno kružnog oblika, krive relativnog spektralnog ubrzanja Sa/Sa,y određene IDA analizama su elipsoidnog oblika ili složenije forme. U početnom delu istraživanja odnosa kapacitet konstrukcije/seizmički zahtev 2D i 3D modela okvirnih zgrada definisani su opšti modeli odnosa pushover krivih i krivih zahteva (BR/SD), a koji su poslužili kao podloga za dalja razmatranja ciljnih pomeranja. U drugom delu je razvijena iterativna metoda koeficijenata pomeranja (IDCM - Iterative Displacement Coefficient Method) kojom su određeni nivoi ciljnih pomeranja. Na osnovu IDCM metode i sprovedenih numeričkih testova na pushover krivama standardizovanih modela odgovora i random funkcija odgovora, utvrđeno je da se postiže veoma zadovoljavajuće slaganje vrednosti driftova realizovanih prema IDCM i NDA analizi. Takođe, minimalna su odstupanja relativne vrednosti ukupne smičuće sile u osnovi objekta realizovana IDCM metodom, u odnosu na rešenja dobijena NDA metodom pri nivoima ciljnih pomeranja (V/W)t. U trećem delu je sprovedeno istraživanje za nivo seizmičkog zahteva 3D modela zgrada, a prezentovano je preko anvelope ciljnog pomeranja (target displacement envelope) i driftova za: performansne nivoe, srednju vrednost, medijanu ciljnog pomeranja i maksimalno pomeranje. Takođe, prikazane su i relativne vrednosti ukupnih smičućih sila u osnovi zgrade za ciljna pomeranja i za maksimalni globalni drift. Na osnovu definisane anvelope ciljnog pomeranja razvijen je niz koeficijenata kojima se ocenjuju performanse 3D modela zgrada. Takođe, performanse zgrada su analizirane i primenom razvijene površi globalnog drifta (drift surface) i površi međuspratnog drifta (interstorey drift surface). U četvrtom delu je, na osnovu razvijene NSPA analize zasnovane na principu projektovanja zgrada prema mehanizmima loma (NSPA-DMBD - Nonlinear Static Pushover Analysis - Damage Mechanisms-Based Design) i istraživanjem na modelu okvirnog sistema, ukazano da je čak kod inicijalne NSPA analize indikator nepovoljnog mehanizma loma bio preko graničnih dilatacija betona. Kod nižih spratova, prema NSPA-DMBD metodi, vrednosti međuspratnih driftova se redukuju, dok se kod viših spratova povećavaju uravnotežujući na taj način odgovor konstrukcije.

Research of 2D and 3D models of frame building system according to the performances for the seismic action, and in accordance with the Performance-Based Earthquake Engineering (PBEE) methodology is presented in this doctoral dissertation. Research can be classified into four distinctly different areas: research in the field of ground motion record and response spectra, research in the field of nonlinear response of 2D model system frameworks that participate in building structural system framework (decomposed or treated as independent entities), research in the field of nonlinear response of 3D model frameworks and research in the field of the relationship of building capacity/seismic demand of 2D and 3D model frameworks. Research in the field of ground motion record is based on the application of natural earthquakes and artificial earthquakes. Previously, the two-componential ground motion records of natural earthquakes are selected and downloaded from the PEER GMDB database. Artificial ground motion records were considered as incomplete and complete non-stationary artificial accelerograms, whereby when creating complete non-stationary artificial accelerograms the analysis of seismic hazard is taken into consideration. The signal processing theory is used for analysis of accelerograms: formatting, converting, scaling, calculation, processing, spectral matching, filtering, generating and transformation. The process of generating inter-components of accelerograms by angles is carried out by rotating components of accelerograms in the fault parallel and fault normal direction. The ground motion record surface is created integrating inter-components of accelerograms. Based on the generated inter-components of the accelerograms the response spectra are developed and integrated into the response spectra surface. For all accelerograms and response spectra intensity measures were analyzed and the intensity measure envelopes were created. The research examined the aspects of scaling and spectral matching of accelerograms and their impact on the form of the response spectra surface. Research in the field of nonlinear response of 2D model system frameworks is based on the application of the beam finite elements, whose cross-section is discretized into fibers and which take into account the development of inelastic deformations. The general models of the pushover curves are defined, which served as a basis for a further consideration in this doctoral dissertation: highly ductile, highly or medium ductile, low or brittle behavior of buildings and transitional category. Also the classification of the pushover curves is implemented by variation of ductility, ductility in the field of stiffening/softening and coefficient of the relation of stiffness in nonlinear and linear domain. By applying these three parameters the set of typological model of the pushover curves is generated for 2D and 3D models of framework buildings. Research the type of distribution of lateral seismic loads for the NSPA pushover analysis was conducted considering the solutions obtained from the INDA analysis of earthquakes. The parabolic distribution is proposed as an alternative to the uniform and equivalent. The advantage of this distribution is demonstrated by comparing with the solution obtained from the regression analysis for a group of earthquakes or discrete values of the INDA analysis. Also, research has found that the application of the pushover curve for the uniform distribution of the lateral seismic loads is achieved quite good coverage of the INDA envelope in the capacity domain. Exploring the impact of the TU (total updating), IU (incremental updating) and HU (hybrid updating) is discussed for 2D model system frameworks, where the highest quality solutions are obtained for the NSPA-DBA analysis, compared to the INDA analysis. In order to determine the required number of the NDA analysis within one INDA analysis, a method is developed based on the solution obtained from the NSPA analysis. On the other hand, in order to predict a solution that is obtained from the INDA analysis of 2D and 3D models of framework buildings with the possibility of considering the response of the system in the capacity domain, but not significantly increasing the time required to process, the Hybrid Incremental Nonlinear Static-Dynamic Analysis (HINSDA) is developed. Higher values of drifts are obtained in a case of application of PGA-IDRmax parameters, than in a case of application of PGA-DR parameters. The least deviation of the HINSDA curve to the INDA curve is obtained using the third UBEPKHS constitutive model, while the maximum deviation is obtained using the first UBEPKHS constitutive model. Research in the field of non-linear response of 3D models of framework buildings is based on the application of the beam finite elements, while at the ends of the beams and columns are applied plastic hinges which enable the development of inelastic deformations. Effects of existence of interstorey plates were modeled using the link elements. Given that in 3D models of framework buildings nonlinear response is considering using the pushover curves for different angles of seismic actions, the pushover surface is obtained by integrating the pushover curves for the NSPA and the INDA (IDA) analysis. The general model of the pushover surface is shown and some specific models of the pushover surfaces are pointed. The typological models of NSPA pushover surfaces are defined as a function of variations in ductility, ductility in the field of stiffening/softening and coefficient of the relation of stiffness in nonlinear and linear domain for one and two main directions. Generally considering, the four groups of pushover surfaces are identified: rotationally polysymmetrice at a base, monosymmetric at a base, bisymmetric at a base and asymmetric at a base. Introducing the ductility area coefficient it is possible to analyze the performance of 3D models of framework buildings taking into account the ductility in all directions or angles of seismic actions. Research has shown that the INDA (IDA) pushover surface has a different shape, compared to the NSPA pushover surface, since the different intensity measure and engineering demand parameter are applied. In order to analyze the performance of 4x6x3, 4x6x5-13, 15x4x4, 15x4x4-6 and 9x6x5-12 3D models of framework buildings, monitoring of the plastic hinges development at incremental stages was conducted, which is presented as isosurfaces in polar coordinates. Also, the implemented curves are discussed in polar coordinates for a drift, the relative value of the total base shear force of building and ductility. Research found that in all models of buildings are realized smaller or something larger maximum global drifts DRmax from global drifts DRIO, for the IO performance level according to the FEMA regulations. The higher ductility class is easier to realize for buildings with a larger number of storeys, and increase in irregularities at a base reduces ductility. Considering the realized NSPA pushover surface in spatial coordinates, for all 3D models of framework buildings, was found that stiffness in the nonlinear domain Kn≈0 is almost horizontal or slightly positive, except in certain cases where with increasing nonlinear deformations stiffness becomes negative Kn<0. For 9x6x5-12 3D model of framework building was realized significantly lower maximum relative value of the total base shear force of building in relation to the relative value of the total base shear force of building for 4x6x3, 4x6x5-13, 15x4x4 and 15x4x4-6 3D models of framework buildings. It is a direct consequence of calculation of the seismic action according to the SRP regulations. In relation to the curve of the relative value of the total base shear force of building (V/W)adeq for maximum global drift DRmax calculated by the NSPA analyses that are circular or nearly circular in shape, curve of the relative spectral acceleration Sa/Sa,y calculated by the IDA analyses are ellipsoidal or more complex forms. In the initial part of research of the relationship of building capacity/seismic demand of 2D and 3D model frameworks the general models of relations for the pushover curves and the demand curves (BR/SD) were defined, which served as a basis for further consideration of target displacements. In the second part of research the Iterative Displacement Coefficient Method (IDCM) was developed, which was used for analyses of the target displacements. Based on the IDCM method and numerical tests conducted on the pushover curves for standardized models of responses and the random response function, it is found that the values of drifts are in very satisfactory agreement according to the IDCM and the NDA analyses. Also, the minimum deviation of the relative value of the total base shear force of building realized by the IDCM method, compared to the solutions obtained by the NDA method at levels of target displacements (V/W)t. In the third part of research the level of seismic demands of 3D models of framework buildings were conducted, and is presented through the target displacement envelope and drifts: for performance levels, mean, median of target displacement and maximum displacement. Relative values of the total base shear force of building for target displacements and maximum global drift are also shown. Based on the defined target displacement envelope a series of coefficients were developed which are used to assess the performance of 3D models of framework buildings. The performances of buildings are analyzed also using the developed global drift surface and interstorey drift surface. In the fourth part, based on the Nonlinear Static Pushover Analysis - Damage Mechanisms-Based Design (NSPA-DMBD) and research on the model of framework system, indicated that even at the initial NSPA analysis unfavorable fracture mechanism was through the ultimate concrete strain. At lower storeys, according to the NSPA-DMBD method, the values of interstorey drifts are reduced, while at the higher storeys are increased thus balancing the response of the structure.

Sinteza nanoprahova i dobijanje kompozitne keramike sa magnetnom i dielektričnom fazom za primenu u mikroelektronici

Synthesis of nanopowders and obtaining of composite ceramics with magnetic and dielectric phase for microelectronic application

U ovom radu sintetisani su kompozitni nanoprahovi i nanoprahovi tipa jezgro– omotač sa dielektričnom i magnetnom fazom, kao pogodan polazni materijal za procesiranje kompozitne keramike za primenu u mikroelektronici. Osnovni cilj ove doktorske disertacije je bio utvrđivanje veza između uslova sinteze, morfologije čestica, uslova procesiranja i mikrostrukture kompozitne keramike. Nanoprahovi su sintetisani hemijskim metodama sinteze u tečnoj fazi (sol-gel i koprecipitacija) i gasnoj fazi (CVS), pri čemu je vršena optimizacija procesnih uslova u cilju sinteze čestica željene strukture i hemijskog sastava. Istraživanja su vršena na nekoliko modelnih sistema sa feritima kao magnetnom fazom i titanatima ili silikom kao dielektričnom fazom: NiFe2O4SiO2, Fe3O4SiO2, SrTiO3NiFe2O4, BaTiO3NiFe2O4 i BaTiO3Fe3O4. Hemijska sinteza u tečnoj fazi se pokazala pogodnom zato što pruža mogućnost kontrolisanja morfologije kompozitnih čestica ne samo podešavanjem procesnih parametara sinteze već i funkcionalizacijom faza kojom se uzrokuje njihovo elektrostatičko privlačenje i formiranje strukture jezgro–omotač. Ipak, zbog velikog stepena aglomeracije prisutnog tokom sinteze u tečnoj fazi, dobijanje omotača uniformne debljine i izbegavanje homogene nukleacije faza se pokazalo teško. Hemijskom sintezom u gasnoj fazi (CVS) je po prvi put sintetisan kompozitni nanoprah na bazi kompleksnih oksida titanata i ferita. Utvrđeno je da i pored velikog potencijala CVS metode u smislu sinteze ultrafinih prahova na bazi titanata i ferita u jednom koraku, ova metoda nudi relativno slabu kontrolu morfologije kompozitnih čestica pri visokim procesnim temperaturama koje su neophodne za kristalizaciju dve faze. Sintetisani nanoprahovi na bazi titanata i ferita (SrTiO3NiFe2O4 i BaTiO3NiFe2O4) procesirani su u gustu kompozitnu keramiku visokotemperaturnim sinterovanjem, u cilju ispitivanja veze morfologije čestica i mikrostrukture kompozita, optimizacije režima sinterovanja i funkcionalne karakterizacije dobijene keramike sa različitim masenim odnosom faza. Prahovi su sinterovani putem konvencionalnog sinterovanja u atmosferi vazduha, spark plazma sinterovanja (SPS) ili kombinacijom ove dve metode. Utvrđeno je da prahovi strukture jezgro–omotač densifikuju u značajno gušću i homogeniju keramiku u odnosu na kompozitne prahove istog sastava na istim procesnim temperaturama. Pored toga, pH vrednost sinteze čestica i atmosfera visokotemperaturnog sinterovanja su se pokazali veoma značajnim u smislu održavanja željenog faznog sastava dobijenih kompozita. U pogledu režima sinterovanja dobijenih prahova, kombinacija niskotemperaturnog konvencionalnog i SPS sinterovanja (1000 °C) je dala najbolje rezultate u smislu postizanja zadovoljavajuće gustine kompozita (>95% teorijske gustine), održavanja željenog faznog sastava i homogene distribucije faza. Funkcionalna karakterizacija sinterovane keramike sa različitim masenim odnosom faza (BaTiO3 : NiFe2O4 = 1,2,8) potvrdila je očekivano dielektrično, feroelektrično i ferimagnetno ponašanje dobijenih kompozita.

Composite and core–shell nanopowders with dielectric and magnetic phase have been synthesized in this work, as a suitable starting material for processing of composite ceramics for microelectronic application. The main goal of this doctoral dissertation was the determination of the link between synthesis conditions, particle morphology, processing conditions and microstructure of composite ceramics. Nanopowders have been synthesized by chemical synthesis methods in wet phase (sol–gel and coprecipitation) and gas phase (CVS), whereas the optimization of processing parameters was conducted with the goal to synthesize particles of desired structure and chemical composition. Studies were conducted on the few model systems with ferrites as a magnetic and titanates as a dielectric phase: NiFe2O4SiO2, Fe3O4SiO2, SrTiO3NiFe2O4, BaTiO3NiFe2O4 and BaTiO3Fe3O4. Chemical wet synthesis has proven suitable because it offers composite particle morphology control not only by adjustment of synthesis parameters but also by phase functionalization causing their mutual electrostatic attraction and thus core–shell structure formation. However, due to the high degree of agglomeration present during the wet phase synthesis, formation of the shell with uniform thickness and avoidance of homogeneous nucleation has proven difficult. For the first time, composite ferrite and titanate-based nanopowder has been synthesized by means of Chemical Vapor Synthesis (CVS). It has been found that beside high potential of CVS method for one-step synthesis of ultrafine titanate and ferrite-based nanopowders, this method offers relatively low control of composite particle morphology at high processing temperatures which are necessary for crystallization of both phases. Synthesized titanate and ferrite-based nanopowders (SrTiO3NiFe2O4 and BaTiO3NiFe2O4) were processed into dense ceramics by high-temperature sintering, in order to find the link between particle morphology and composite microstructure, optimize the sintering regime and conduct the functional characterization of obtained ceramics with different phase mass ratio. The powders were sintered by conventional sintering in air, spark plasma sintering (SPS) or combination of these two methods. It was found that core–shell powders densify in ceramics with considerably higher density and homogeneity at the same processing temperature, than the composite powders with the same composition. Moreover, synthesis pH value and sintering temperature was found to be very important in terms of phase composition preservation of obtained composites. Regarding the sintering regime of obtained powders, combination of low-temperature conventional and SPS sintering (1000 °C) has given the best results in terms of achieving adequate composite density (>95% theoretical density), phase preservation and homogeneous phase distribution. Functional characterization of sintered ceramics with different phase mass ratio (BaTiO3 : NiFe2O4 = 1,2,8) confirmed the expected dielectric, ferroelectric and ferromagnetic behaviour of obtained composites.

Ocena kvaliteta digitalnih topografskih karata

Quality evaluation of digital topographic maps

Kvalitet prostornih podataka predstavlja skup njihovih karakteristika koje odražavaju sposobnost prostornih podataka da ispune određene, unapred formulisane zahteve i/ili zahteve koji se podrazumevaju. Svrha opisivanja kvaliteta prostornih podataka je da omogući poređenje i izbor podataka koji najbolje odgovara potrebama, primeni ili zahtevima korisnika. Kompletan opis kvaliteta jednog podatka će podsticati deljenje, razmenu i korišćenje odgovarajućih skupova prostornih podataka. U ovom radu se, na osnovu teorijskih razmatranja i sprovedenog eksperimenta, ocenjuje kvalitet digitalnih topografskih karata i definiše optimalna metodologija njenog ispitivanja i ocenjivanja, koja se može primeniti na celokupan razmerni niz digitalnih topografskih, preglednotopografskih i geografskih karata izdanja Vojnogeografskog instituta. Pored definisanja optimalnog metodološkog postupka za ocenu kvaliteta prostornih podataka digitalnih topografskih karata razrađeni su oblici i obim ocene kvaliteta u različitim etapama proizvodnog procesa izrade digitalnih topografskih karata. Teorijska razmatranja uključuju, analizu savremenih dostignuća u oblasti kontrole kvaliteta i njene standardizacije, pregled najzačajnijih standarda dizajniranih za ocenu kvaliteta prostornih podataka digitalnih karata. Disertacijom se predlaže korišćenje metodologije, koja se zasniva na međunarodnom standardu ISO 19157. Prostorni podaci koji se izrađuju u Vojnogeografskom institutu (VGI), organizovani su u Centralnoj Geoprostornoj bazi podataka. Ona predstavlja osnovu za generisanje svih digitalnih topografskih karata celokupnog razmernog niza topografskih karata koji se proizvode u VGI-u. Zbog toga jedan deo disertacije sadrži kratak opis modela i organizacije prostornih podataka u okviru Centralne Geoprostorne baze podataka, gde su opisani konceptualni, logički i fizički modeli prostornih podataka. Eksperiment ocene kvaliteta digitalnih topografskih karata sproveden je na celokupnim prostornim podacima koji su sadržaj Centralne Geoprostorne baze podataka u trenutku testiranja. Ocena kvaliteta realizovana je prema definisanim elementima kvaliteta, uz korišćenje odgovarajućih mera kvaliteta prostornih podataka, na osnovu navedenog međunarodnog standarda ISO 19157. Rezultati ocene prikazani su, takođe, na standardizovan način pomoću metapodataka i samostalnih izveštaja o kvalitetu prostornih podataka digitalnih topografskih karata.

The quality of spatial data represent a set of characteristics that reflect to their ability to spatial data to fulfill certain, pre-formulated requirements and/or requirements are considered. The purpose of describing the quality of spatial data is to facilitate the comparison and selection of dataset best suited to application needs or user requirements. A complete description of the data quality shall encourage the sharing, exchange and use of appropriate spatial datasets. This paper, based on theoretical considerations and completing the experiment, analyze the quality of digital topographic maps and define the optimal methodology for its testing and evaluation, which can be applied to the entire range of digital topographic, overview-topographic and geographic maps of Military Geographical Institute. In addition, to defining the optimal methodological procedure for analyzing spatial data quality digital topographic maps were developed forms and scope of the analysis of quality in the various stages of the production process of making digital topographic maps. Theoretical considerations include analysis of contemporary developments in the field of quality control and its standardization, the most significant review of standards designed to analyze the quality of spatial data in digital maps. Dissertation proposes the use of the methodology, which is based on the International standard ISO 19157. Spatial data that are produced in the Military Geographical Institute, organized in Central geospatial database. It is the basis for the generation of digital topographic maps of the entire scale series of topographic maps produced in MGI. Therefore, one chapter of the dissertation contains a brief description of the model and organization of spatial data within the Central Geospatial database, where they described the conceptual, logical and physical models of spatial data. Experiment analysis of the quality of digital topographic maps was carried out on the entire spatial data content of the Central Geospatial database at the time of testing. Quality evaluation was carried out according to defined quality elements, using appropriate measure of the quality of spatial data, on the basis of the above International standards ISO 19157. The results of quality evaluation are also shown, in a standardized manner using metadata and standalone reports on the quality of spatial data digital topographic maps.

Geografske osnove turističke valorizacije Srbije : pozicioniranje urbanih, banjskih i ruralnih naselja Gornje Toplice

The geographical foundations of the touristic valorization of Serbia - the positioning of urban, spa and rural settlements in Upper Toplica

Jedno od najznačajnijih i najkompleksnijih pitanja teoretsko-metodoloških osnova turizma i razvoja istog na konkretnom prostoru je turistička valorizacija. Ona se odnosi na postupak procene pojedinačnih turističkih vrednosti i svih zajedno u određenoj regiji. Svetska organizacija za turizam (WTO) svojim predlozima, koji imaju široku primenu u turističkoj receptivi ukazuje na značaj turističke valorizacije. Bitno je istaći shvatanje da se turistička valorizacija prirodnih i antropogenih vrednosti ne sme izjednačavati sa ekonomskom valorizacijom, jer ni jedna ni druga ne podležu zakonima klasičnog ekonomskog tržišta. U proučavanjima i posmatranjima turističkog prostora Srbije, kroz određene kriterijume uočavaju se pet prioriteta u koje spadaju: Beograd, manastiri, Đerdapski Dunav, Kopaonik i pogranična područja. Kopaonička turistička regija pripada središnjoj turističkoj zoni Srbije. Ima centralni položaj u Srbiji, ali nepovoljniji i slabije saobraćajne povezanosti u odnosu na Zlatibor, Šumadiju i Pomoravlje. Turističku ponudu Kopaonika moguće je proširiti, pri čemu se izdvajaju dva pojasa okruženja primarne ponude Kopaonika; uži potkopaonički i širi korelacioni. Kao subregija Kopaoničke turističke regije može se izdvojiti prostor Gornje Toplice, od izvorišta ove reke do uliva njene veće pritoke reke Kosanice. Uži potkopaonički pojas obuhvata sliv Lukovske i Blaževačke reke, gde se kao turistički lokalitet ističe Lukovska Banja. U širem korelacionom pojasu je reka Toplica koja obuhvata jezero „Selova“, gradsko naselje Kuršumlija i Kuršumlijsku Banju. Prostor koji ne pripada Kopaoničkoj turističkoj regiji, a pripada regiji Gornje Toplice je Prolom Banja, Đavolja Varoš i Radan planina koja pripada slivu reke Kosanice. Ovaj prostor se u odnosu na ostale delove Kopaoničke regije izdvaja po svojim specifičnostima, broju i raznovrsnosti prirodnih potencijala. Banjska, ruralna i urbana naselja sa svojim specifičnostima su osnova za analizu turističkih vrednosti na prostoru Gornje Toplice. Pored, prirodnih i antropogenih motiva kao temeljnih turističkih resursa, uključuje elemente opšte i turističke infra i suprastrukture, kao i plansko-organizacione elemente, instuticionalne činioce i ljudske resurse neophodne za turističko privređivanje, kao i njihova uloga u turističkoj valorizaciji Srbije. Prirodne i antropogene vrednosti tretiranog prostora, kroz kompleksan postupak turističke valorizacije, mogu dobiti adekvatno mesto i izraz u turističkoj ponudi koja se plasira na tržištu. Atraktivni atributi turističkih motiva datog prostora su neosporni, ali je neophodno da se kroz kompleksnu evaluaciju njihovih upotrebnih i tržišnih vrednosti adekvatno i celovito sagleda resursna osnova za razvoj turizma Gornje Toplice. Adekvatnim sagledavanjem ukupnih turističkih mogućnosti i dosadašnjih turističkih rezultata u naseljima Gornje Toplice, mogu se projektovati validni i realni ciljevi i zadaci razvoja ove delatnosti u narednom periodu. Na taj način se, uz postojeće izvore privređivanja i obezbeđenja materijalne egzistencije lokalnim zajednicama, na ovom prostoru može stvoriti nova i šira tržišno orijentisana razvojna osnova, koja bi podigla kvalitet života domicilnog stanovništva i poboljšala socio-kulturno i ekonomsko stanje u naseljima Gornje Toplice. Metodologija rada je usklađena sa predmetom, ciljevima i zadacima istraživanja. Struktura predviđenog istraživanja, u naseljima Gornje Toplice, zahteva korišćenje rezultata geografskih, istorijskih i drugih nauka, kao i upotrebu brojnih naučnih metoda. Primarnu ulogu će imati sledeće metode: prostorna (geografska) metoda, terenska istraživanja, istorijska metoda, statistička obrada istražene literature i drugog materijala, kvantitativna i kvalitativna analiza sadržaja, kartografska metoda, komparativna metoda, metode turističke valorizacije Svetske turističke valorizacije, PESTEL analiza i SWOT analiza. Prostorna metoda ukazuje na predeone razlike i turističko geografsku homogenost prostora u kome se nalaze brojne turističke vrednosti. Terenska istraživanja su nezaobilazni deo ove disertacije i ona se iskazuju kroz neposredno i sistemsko posmatranje, kao i sprovođenje anketa i intervjua. Istorijska metoda pomoću korišćenja literature, pisanih dokumenata i druge arhivske građe pruža nam saznanja o prošlosti turističkih vrednosti ovog prostora, objašnjava postojeće stanje i omogućava izvođenje prognoza i projekcija budućeg turističkog razvoja. Kartografska metoda omogućiće prikaz prostornog razmeštaja turističkih lokaliteta u Gornjoj Toplici, osnovnih i komplementarnih motivskih vrednosti, kao i njihovog položaja u odnosu na saobraćajno-turističke pravce i emitivna područja tražnje, na temelju čege se mogu izvući relevantni i jasni zaključci. PESTEL analizom će se razmatriti pojedinačni i zajednički uticaji političkih, ekonomskih, socijalnih, tehničko-tehnoloških, ekoloških i pravnih faktora na razvoj turizma u naseljima Gornje Toplice; dok će SWOT analiza poslužiti za identifikovanje ključnih prednosti i nedostataka vezanih za resurse za razvoj turizma, kao i sagledavanje šansi koje se mogu iskoristiti ali i rizika koji ugrožavaju (limitiraju) mogućnosti za budući razvoj turizma na datom prostoru.

Touristic valorization is of the most important and most complex questions of the theoretically – methodological foundations of tourism and its development in a given area. It’s related to the procedure of estimating particular and altogether touristic values and in a specific region. The World Tourism Organization (WTO), by its proposals having broad use in the touristic reception services, indicates the importance of the touristic valorization. It is important to emphasize an understanding that the tourist valorization of natural and anthropogenic values must not be equated with economic valorization, since none of these is the subject of the laws of the classical economic market. In explorations and observations of the touristic area in Serbia, five priorities can be noticed through certain criteria and the priorities are the following: Belgrade, monasteries, The Djerdap part of the Danube River, Kopaonik and borderland. The Kopaonik tourist region belongs to the central tourist zone of Serbia. It has a central position in Serbia but substantial disadvantage in traffic links in relation to Zlatibor, Sumadija and Pomoravlje. The tourist offers of Kopaonik can be expanded, wherein two zones of the surroundings of the Kopaonik’s primary offer are separated: the sub – Kopaonik area (the narrower one) and the correlating (the broader one). The Upper Toplica area can be distinguished as the sub-region of the Kopaonik touristic region, the area stretched up from the spring of the Toplica river up to the confluence with its larger feeder, the Kosanica River. The narrower sub-Kopaonik area contains the basin of Lukovska and Blazevacka Rivers, where the Lukovska Spa represents a touristic site. In the broader correlating zone which includes the “Selova” lake, there’s the urban settlement of Kursumlija and Kursumlijska Spa. The area which does not belong to the Kopaonik touristic region but situated in Upper Toplica region is Prolom Spa, Devil’s Town and Radan Mountain which belongs to the Kosanica river basin. This area is distinguished from the other parts of Kopaonik region by its specificities, the number and diversity of natural potentials. The spa, urban and rural settlements with their specificities stand for the corner-stone for the analysis of touristic values in the Upper Toplica area. Beside the natural and anthropogenic motifs as foundational touristic resources, it includes some elements of general and touristic infra and supra structure, as well as the planned- organizational structure, institutional factors and human resources necessary for a touristic economic activities, as well as their role in touristic valorization of Serbia. The natural and anthropogenic values of the given region, through a complex procedure of touristic valorization, can get an adequate place and expression in touristic offer placed in the market. Attractive attributes of touristic motifs of the actual zone are indisputable but, it’s necessary to observe the basis of resources for the Upper Toplica’s touristic development, through complex evaluation of their value in use and current value and via adequate observance of a summary of touristic possibilities. Via adequate observance of a summary of possibilities and up-to-date touristic results in settlements in Gornja Toplica, some valid and real goals and tasks for development of this activity in the forthcoming period may be projected. That way, including the existing resources of economic activities and providing material existence to local communities, this area can be the place for enabling the new and broader market-oriented base for development, which may raise the quality of living to domicile population and improve the social-cultural and economic position in the Upper Toplica settlements. The methodology of work is harmonized with the subject, goals and tasks of researches. The structure of the provided research in the Upper Toplica settlements necessitates usage of the results of geographical, historical and other disciplines, as well as using a number of scientific methods. The following methods will get the leading role: spatial (geographic) method, field researches, historical method, statistical processing of the read literature and other materials, quantitative and qualitative content analysis, , cartographic method, comparative method, the method of touristic valorization of the World Tourism Organization, PESTEL analysis and SWOT analysis. The spatial method indicates the differences in landscapes and the touristic – geographical homogeneity of the area in which many touristic values are situated. The field researches are an unavoidable part of this dissertation and can be expressed through first-hand and system observation, as well as making interviews and inquiries. The historical method explains present state and allows making prognoses and projections of the future touristic development. The cartographic method will facilitate an illustration of special layout of touristic places in Upper Toplica, basic and complementary motif values, as well as their position in relation to the traffic and touristic directions and generating tourism areas, on the basis of which some relevant and clear conclusions can be made. By PESTEL analysis particular and common influences of political, economical, social, technically – technological, ecological and legal factors impacting the Upper Toplica area will be considered, while SWOT analysis will serve for identifying the key advantages and disadvantages related to the resources for tourism development, as well as perceiving the chances that can possibly be used and the risks which jeopardize (constrain) the options for future touristic development in the given area.

Predicting land use change with data-driven models

Predviđanje promena u korišćenju zemljišta primenom modela vođenih podacima (DATA-DRIVEN MODELS)

Jedan od glavnih zadataka modeliranja metoda vođenih podacima (Data-driven methods) je pronalaženje reprezentativnog modela ispitivnog prostorno vremenskog procesa, primenom podataka iz prošlosti i Data Mining i Machine Learning pristupa...

One of the main tasks of data-driven modelling methods is to induce a representative model of underlying spatial - temporal processes using past data and data mining and machine learning approach. As relatively new methods, known to be capable of solving complex nonlinear problems, data-driven methods are insufficiently researched in the field of land use. The main objective of this dissertation is to develop a methodology for predictive urban land use change models using data-driven approach together with evaluation of the performance of different data-driven methods, which in the stage of finding patterns of land use changes use three different machine learning techniques: Decision Trees, Neural Networks and Support Vector Machines. The proposed methodology of data-driven methods was presented and special attention was paid to different data representation, data sampling and the selection of attributes by four methods (χ2, Info Gain, Gain Ratio and Correlation-based Feature Subset) that best describe the process of land use change. Additionally, a sensitivity analysis of the Support Vector Machines -based models was performed with regards to attribute selection and parameter changes. Development and evaluation of the methodology was performed using data on three Belgrade municipalities (Zemun, New Belgrade and Surčin), which are represented as 10×10 m grid cells in four different moments in time (2001, 2003, 2007 and 2010). The obtained results indicate that the proposed data-driven methodology provides predictive models which could be successfully used for creation of possible scenarios of urban land use changes in the future. All three examined machine learning techniques are suitable for modeling land use change. Accuracy and performance of models can be improved using proposed balanced data sampling, including the information about neighbourhood and history in data representations and relevant attribute selections. Additionally, using selected subset of attributes resulted in a simple model and with less possibility to be overfitted with higher values of Support Vector Machines parameters.

Modeliranje regionalnih deformacija zemljine kore i stabilnosti referentnog sistema

Ova disertacija je urađena u kontekstu nastavka geodetskih istraživanja realizacije i stabilnosti odnosno vremenske evolucije Terestričkog Referentnog Sistema i savremenih pomeranja Zemljine kore regionalnog karaktera koja se izvode u okviru uže naučne oblasti Referentne geodetske mreže za koju je matičan Građevinski fakultet Univerziteta u Beogradu. Zemljina kora kao najviši deo u strukturnoj građi Zemlje trpi promene pod istovremenim i suprostavljenim dejstvom endogenih i egzogenih procesa. Prema modelu tektonike ploča Zemljina kora je podeljena u određen broj tankih, krutih ploča koje se kreću jedna u odnosu na drugu i čije su granice definisane seizmičkom aktivnošću. Visoka preciznost pozicioniranja ostvarena danas pomoću prostornih geodetskih tehnika VLBI, SLR, GPS i DORIS omogućila je dobijanje informacija o kinematici tektonskih ploča na osnovu ponovljenih ili kontinuiranih opažanja. Satelitski sistemi kao što je GPS sistem omogućuju opažanja pomoću kojih se dobijaju vremenske serije koordinata stanica na fizičkoj površi Zemlje sa milimetarskom tačnošću. Globalne mreže permanentnih stanica predstavljaju standarde za geodetsko pozicioniranje kao i za kvantifikovanje kretanja velikih litosfernih kontinentalnih ploča. Regionalne i lokalne mreže permanentnih GNSS stanica predstavljaju polaznu osnovu kod zadataka geodetskog pozicioniranja i geodetskog doprinosa geodinamičkim istraživanjima. Za interpretaciju geodetskih merenja, za izvođenje studija o deformacijama kao i da bi izvršena opažanja imala fizički smisao, primenjuje se odgovarajući globalni referentni sistem. Za istraživanja deformacije Zemljine površine potreban je referentni okvir fiksiran za Zemlju poznat pod nazivom Terestrički Referentni Okvir, koji ima ključni značaj u geodeziji i drugim geonaukama i predstavlja univerzalni standard. Međunarodni Terestrički Referentni Sistem, ITRS prema IERS Konvenciji, 2010 podrazumeva sledeće: 1) početak ITRS se nalazi u geocentru i predstavlja zajednički centar mase čvrste Zemlje, okeana i atmosfere, 2) sistem rotira zajedno sa Zemljom u njenom dnevnom kretanju u prostoru i 3) orijentacija sistema je ekvatorijalna pri čemu je Z osa u pravacu pola i ima za jedinicu dužine SI metar. Istraživanja u ovom radu su izvršena sa ciljem realizacije i ocene stabilnosti Terestričkog Referentnog Sistema, postizanja reprezentativnosti kinematike regionalne oblasti Republike Srbije i dobijanja ocena geodetskih kvantiteta deformacija ove oblasti. Osnovu za dobijanje ocena čini mreža permanentnih GPS stanica Srbije koje obezbeđuju kontinuirana merenja tokom više godina. Na osnovu dobijenih vrednosti brzina stanica izvršena je ocena kvantiteta ekstenzionih i kompresionih deformacija Zemljine površine. Da bi ove ocene bile tačne, od ključne važnosti je da su osnovna (i buduća) merenja deformacija i brzina deformacija na najvišem nivou tačnosti i preciznosti. Iz tog razloga trebalo bi ostvariti visoku stabilnost i dugoročnost Referentnog sistema. Pored toga, upoređenje i korelacija sa geološkim modelima doprinosi razumevanju geodinamičkih procesa ove oblasti i rezultati istraživanja se mogu koristiti za uključivanje u više međunarodnih projekata kao što je na primer projekat European Dense Velocity Field Rroject.

This PhD. thesis is done in the context of continuing geodetic research and realization of stability and temporal evolution of the Terrestrial Reference System and recent displacement of the Earth's crust which have a regional character that are perform within the scientific geodetic field the Geodetic Reference Network for which is academically competent the Faculty of Civil Engineering of the University of Belgrade. As the highest part of the structural composition of the Earth, the Earth's crust suffer changes under the simultaneous and opposed effects of endogenous and exogenous processes. According to the model of plate tectonics, the Earth's crust is divided into a some number of thin, rigid plates that have a relative motion, i.e. the one in relation to another plate, and have boundaries that are defined by seismic activity. High precision of positioning achieved today with the spatial geodetic techniques VLBI, SLR, GPS and DORIS, enabled to obtain the information on kinematics of tectonic plates on the basis of repeated or continuous observations. Satellite systems such as the GPS system, allow observations which are the basis for obtaining the coordinate time series of the stations on the physical surface of the Earth with a millimeter accuracy level. A global network of permanent stations provide the standards for geodetic positioning as well as for quantifying the movements of large continental plates of lithosphere. Regional and Local permanent GNSS networks represent a basis in the geodetic positioning tasks and also for geodetic contribution to geodynamic research. Appropriate global reference system is used for the interpretation of geodetic measurements, for the study of the deformation Earth's crust and, also in order to have the observations with physical meaning. Investigations of the deformation of the Earth's surface requires a Earth-fixed Reference Frame known as the Terrestrial Reference Frame, which is a universal standard frame and crucial in geodesy and other geosciences. In accordance with the recommendations provided by IERS Convention, 2010, International Terrestrial Reference System, ITRS include the following: 1) ITRS origin is in the geocenter and represents a common center of mass of the solid Earth, the ocean and the atmosphere, 2) system rotates together with the Earth in its daily movement in space and 3) the orientation of system is equatorial wherein Z axis is in direction of pole and unit length is SI meter. In this thesis researches were conducted with the aim to realize and evaluate the stability of the Terrestrial Reference System, in order to achieve a representativeness kinematics of regional area of the Republic of Serbia and derivation the estimates of geodetic deformation quantity of this area. The basis for derivation the estimates represents the network of permanent GPS stations of Serbia, through which are realized the continuous measurements over several years. Based on the estimated station velocity is carried out the assess of quantity of extensional and compressive deformation of the Earth's surface. To make these estimates were correct, it is crucial that the basic (and future) strain measurement and strain rate are on the highest level of accuracy and precision. For this reasons, we should realize the high stability and long-term reference system. In addition, comparison and correlation with geological models contributes to the understanding of the geodynamic processes in this area and the results of the research can be used to engage in international projects, such as for example the European Dense Velocity Field Project.

Marketing strategije najvećih izvoznika : međunarodna komparativna analiza relevantna za Srbiju

Marketing strategies of the largest exporters : the international comparative analysis relevant for Serbia

Predmet ove disertacije su marketing strategije najvećih izvoznika iz Srbije. U istraživanje su uključeni i izvoznici iz Belorusije, Grčke i Češke da bi se predmet istraživanja detaljnije ispitao primenom komparativne metode. Teorijsku osnovu su činili kontingentni pristup objašnjenju izvoznih marketing strategija i sistematska analiza prethodnih studija. Četiri grupe hipoteza su obrazovane. Empirijsko istraživanje je bilo utemeljeno na pozitivističkoj naučnoj paradigmi i kvantitativnom istraživačkom dizajnu. Njegov međunarodni karakter je zahtevao ekvivalenciju na nivou teorijskog konstrukta, prikupljenih podataka i merenja. U istraživanju je učestvovalo 474 preduzeća. Ostvarena je prosečna nominalna stopa odziva od 39,5 odsto. Dobijeni rezultati su potvrdili da se za proizvod primenjuje najviši nivo ujednačavanja uprkos različitostima poslovnih okruženja u zemljama uključenim u istraživanje. U slučaju Srbije odlike preduzeća koje utiču na izvoznu marketing strategiju su vlasništvo nad kapitalom i izvozno iskustvo. U slučaju Belorusije pored vlasništva nad kapitalom, uticaj imaju i veličina preduzeća, i tehnologija procesa proizvodnje. Grčki i češki slučaj dokumentuju uticaj svih istraživanih odlika preduzeća. Potvrđeno je i postojanje paradoksa psihološke udaljenosti, i potreba da se taj koncept posmatra u širem smislu. U slučajevima Srbije i Belorusije on utiče na izvoznu marketing strategiju, a u slučajevima Grčke i Češke ne utiče. Nije potvrđeno postojanje uticaja ni strategije ujednačavanja, niti strategije prilagođavanja na zadovoljstvo učinkom u izvozu. Osnovni doprinosi disertacije su obogaćivanje postojećeg fonda znanja o izvoznim marketing strategijama podacima iz četiri skromno istražena slučaja izvoznika iz Srbije, Belorusije, Grčke i Češke, sistematski pristup istraživanim pojavama, komparativni karakter datih objašnjenja, i replikativna priroda procesa istraživanja.

The topic of this dissertation is the marketing strategies of the largest exporters from Serbia. The research included exporters from Belarus, Greece and the Czech Republic, as well, in order to explore the topic in more details using the comparative method. The theoretical framework was founded on contingency theory in explanation of the export marketing strategies and in systematic analysis of previous studies. The four groups of hypotheses are setted. Empirical research was based on the positivistic scientific paradigm and a quantitative research design. International character of survey required equivalence in set of the level of the theoretical construct, data collection and the measurements. The survey involved 474 firms. Аn average nominal response rate of 39.5 percent was reached. The obtained results confirmed that in spite of the differences in business environment in reserach related countries, all firms use the highest level of standardization strategy for product. Capital ownership and export experience are firms' characteristics that influence export marketing strategy in Serbia. Beside capital ownership, firm size and technological level of production process influence export marketing strategy in the case of firms from Belarus.The Greek and Czech cases document the impact of all of the researched firms' characteristics. Results confirmed existence of psychic distance paradox and need for exploration of this phenomenon in wider sense, because in cases of Serbia and Belarus it does affect the export marketing strategy, but in cases of Greece and Czech Republic it does not. Nor standardization, neither adaptation strategy implementation by itself can ensure satisfaction with the export performance. It is necessary to check strategic roots of export marketing strategies and to tie them with a number of qualitative, macro and micro level indicators. The main contributions of the dissertation are the expansion of the existing knowledge on export marketing strategies with data from four modest examined cases of exporters from Serbia, Belarus, Greece and Czech Republic, systematic approach to investigated phenomena, comparative character of explanations, as well as the replicative nature of the entire research process.

Tačnost modeliranja objekata tehnologijom terestričkog laserskog skeniranja

Accuracy of the objects modelling using terrestrial laser scanning technology

Skorašnja unapređenja performansi sistema terestričkog laserskog skeniranja (TLS) i trend opadanja cene ukazuju na značajan potencijal ove tehnologije i u zahtevnim inženjerskim zadacima. Pored činjenice da pojedini TLS poseduju frekvenciju skeniranja i preko 1.000.000 Hz, aspekt tačnosti ove metode geodetskog merenja igra presudnu ulogu u inženjerstvu. Postizanje adekvatne tačnosti modeliranja objekata tehnologijom TLS se osigurava projektovanjem geodetskog eksperimenta. To podrazumeva optimizaciju relevantnih parametara merenja i metodologije obrade podataka, kroz analizu uticaja različitih izvora grešaka u procesu merenja, instrumentalne preciznosti i performansi TLS, sagledavanja prostorne konfiguracije objekta i analize grešaka modela registracije i georeferenciranja. U radu su date osnove tehnologije TLS, matematički modeli opažanja, registracije i georeferenciranja. Predstavljeni su i analizirani različiti izvori grešaka merenja TLS koje potiču od instrumenta, sredine, objekta skeniranja i metodologije registracije i georeferenciranja. Predstavljena su trenutna dostignuća i ograničenja kalibracije TLS. Date su osnovne postavke 3D modeliranja oblaka tačaka tehnikama MNK uklapanja površi i zapreminskog modeliranja. Predložena je pojednostavljena procedura ispitivanja TLS po kriterijumima standarda ISO17123. Ona obuhvata ispitivanje, analizu i ocenu tačnosti TLS u laboratorijskim uslovima, po ugledu na postupke kalibracije sistema i mreže skenerskih signala. Metrološka laboratorija Građevinskog fakulteta u Beogradu je prilagođena za postupke ispitivanja TLS i izvršeno je ispitivanje jednog modela TLS. Najvažniji rezultati disertacije odnose se na: formiranje proširenog stohastičkog modela direktnog georeferenciranja, ustanovljavanje metodologije projektovanja merenja TLS na inženjerskim objektima i metodologiju indirektnog georeferenciranja linijskih objekata. Modifikovan je kompletan teorijski model grešaka direktnog georeferenciranja, korišćenjem procedure poznate stanice i orijentacije, i to u formi kovarijacione matrice vi koordinata tačaka. Ona sadrži sve relevantne uticaje, i to: deklarisanu preciznost rezultata TLS merenja, uticaje datih veličina kontrolne geodetske mreže, greške centrisanja, horizontiranja i merenja visine TLS i greške centrisanja i viziranja signala. Model je formiran na osnovu uticaja pojedinačnih izvora grešaka na vektor translacije i rotacije sistema oko z-ose. U metodologiji optimizacije parametara skeniranja polazi se od analize uticaja različitih izvora grešaka na tačnost skeniranja objekta, odnosno od definisanja dominantnih uticaja na rezultate opažanja. Projektovanje eksperimenta TLS koje uključuje i optimizaciju parametara skeniranja izvršeno je na osnovu geometrijskih karakteristika test objekta u vidu 12 železničkih tunela. Izvršeno je projektovanje lokacija stanica TLS, dozvoljene dužine vizure i uglovne rezolucije skeniranja. Optimizacija je izvršena na osnovu ključnih ograničavajućih faktora: veličine upadnog ugla laserskog zraka na površ objekta, teorijskog doprinosa upadnog ugla intenzitetu povratnog zračenja i principa zanemarljivosti komponenti varijansi rezultata merenja rastojanja. Predložena metodologija projektovanja se odnosi na skeniranje objekata izduženog oblika (cevovodi, tuneli, podzemni hodnici, putevi itd.), koji generalno predstavljaju nepovoljan slučaj u smislu ostvarivanja potrebne tačnosti i pouzdanosti geodetskog eksperimenta. Maksimalna dozvoljena vrednost upadnog ugla laserskog zraka pri datim gabaritima test tunela iznosi 78º, maksimalna dozvoljena dužina vizure 13 m, rastojanje između susednih stanica TLS 26 m i optimalna vrednost uglovne rezolucije skeniranja iznosi 60". Predložen je metod kontrolisanja multiplikacije grešaka registracije scena, uvođenjem arbitrarnog pristupa pri indirektnom georeferenciranju oblaka tačaka u dva koraka. Na osnovu podataka skeniranja tunela dugačkog 1260 m, pokazana je efikasnost arbitrarnog pristupa u postizanju zahtevane tačnosti modela prostorne transformacije u odnosu na klasičan pristup. Time je ostvarena mogućnost postizanja visoke apsolutne tačnosti modela inženjerskog objekta i u uslovima nepovoljne geometrije za sprovođenje geodetskog eksperimenta. Standardna greška arbitrarnog georeferenciranja, odnosno 3D apsolutna standardna greška konačnog oblaka tačaka u najdužem tunelu iznosi 10.6 mm, dok standardnom metodologijom indirektnog georeferenciranja te greške dostižu i vrednost od 1 m. vii

In high-demanding engineering applications, the latest performance improvements of the terrestrial lasers scanning (TLS) system and price decreasing trend shows the significant potential of this technology. Beside the fact that some scanners have the scanning frequency of over 1.000.000 Hz, in the engineering applications the accuracy of this survey method plays the key role. Achievement of the satisfactory accuracy of the object modelling using TLS has to be done by experiment designing. This implies the optimization process of the relevant measurements parameters and of the methodology of measurement processing through analysis of the different sources of measurement errors, instrumental precision and performance of the specific TLS, spatial configuration of the object and analysis of the models of registration and georeferencing errors. This work presents the fundamentals of TLS technology, mathematical models of measurements, registration and georeferencing. The different types of errors and their influences on the measurement quality are presented and analyzed. The sources of these errors are discussed in detail and treated as instrumental, environmental, object related and registration and georeferencing methodology dependent. The present TLS calibration achievements and existing operational limits are also analyzed. The basics of the point cloud 3D modelling techniques based on the least square fitting and volumetric approaches are given. The simplified test procedure of the TLS accuracy investigation in accordance with the ISO17123 standard is proposed. The proposed procedure covers investigation, analysis and accuracy estimation of the TLS system in laboratory conditions. This procedure is developed based on the model of the system calibration and the network design procedures. Metrological laboratory of the Faculty of Civil Engineering in Belgrade is customized for TLS testing. The accuracy investigation of a commercial TLS has been performed. ix The most important thesis results are related to the establishment of the outspread stochastic model of the direct georeferencing, methodology of the TLS measurements design and indirect georeferencing approach for the elongated engineering objects. The complete theoretical error model is modified for the case of the direct point cloud georeferencing using procedures of the TLS centering and orienting. The model is given in the form of a variance-covariance matrix of the point coordinates in the control network coordinate system. The variance-covariance matrix contains all significant influence factors, such are: instrumental precision of the TLS linear and angular measurements, the uncertainty of the geodetic control network, TLS centering, levelling and height measuring errors and errors of the signal centering and pointing. The error model is developed based on the influence of individual factors/error sources on the translation vector and rotation vector around z-axis. The proposed methodology of the optimization of the scanning parameters starts from the analysis of the different error sources on the scanning accuracy, segregation of the significant influences in the present object configuration conditions. TLS experiment design that includes the optimization of the scanning parameters is conducted based on the case geometry of the 12 railway single-track tunnels. On this test example, the location of the TLS stations, allowed scanning distance and angular scanning resolution are designed. The optimization is performed by taking into account the essential limiting factor such as the incidence angle of the laser beam to the object surface, theoretical contribution of the incidence angle to the signal deterioration and the neglectivity principle of the variance components of the measured range. The proposed methodology is related to the scanning of elongated objects (tunnels, corridors, pipelines, underground passages etc), which generally represent unfavourable cases in providing geodetic measurements of sufficient accuracy and reliability. The maximal favourable incidence angle of the laser beam in the case tunnels is 78ﾟ, maximal scanning distance is 13 m, and consequently the optimal size of the scanner shifting along the tunnel alignment is 26 m and optimal scanning angular resolution is 60". The methodology of the arbitrary georeferencing in two steps is also proposed. This approach holds the final point cloud geometric distortion, due to scans registration x errors multiplication, to the given limits. For the 1260 m long tunnel example, efficiency of the arbitrary georeferencing approach is shown as opposed to the classical indirect approach. This creates the possibility of achieving the high geometric accuracy of the engineering object model, even in the environment unfavourable for the geodetic measurements. Standard error of the arbitrary georeferencing method in the longest example tunnel is 10.6 mm, while residuals of the standard indirect georeferencing approach goes up to 1 m.

Teorijska i eksperimentalna analiza nosača od lepljenog lameliranog drveta ojačanih karbonskim trakama

Theoretical and experimental analysis of glulam beams reinforced with CFRP plates

Ideja o ojačanju nosača od lepljenog lameliranog drveta došla je kao odgovor na potrebu poboljšanja mehaničkih karakteristika, kao i obezbeđivanja veće pouzdanosti ovih konstrukcijskih elemenata. Tokom prethodnih desetak godina primena polimera ojačanih vlaknima (FRP) za ojačanje i sanaciju konstrukcija je značajno povećana. Karakteristike kao što su mala težina, visoka krutost i čvrstoća na zatezanje, koroziona otpornost i širok spektar raspoloživih veličina i oblika su neki od razloga koji opravdavaju rastuću upotrebu ove vrste materijala. Mada su intezivna istraživanja primene FRP kompozita sprovedena za armiranobetonske i zidane elemente, vrlo ograničene informacije su dostupne vezano za primenu u drvenim konstrukcijama. U okviru ove teze se istražuju mogućnosti primene karbonskih (CFRP) traka kao ojačanja lepljenih lameliranih drvenih nosača. Eksperimentalni, analitički i numerički pristupi su korišćeni u cilju procene efekta ojačanja na ponašanje nosača pri savijanju. Posebna pažnja je usmerena ka utvrđivanju optimalnog položaja ojačanja koji će omogućiti maksimalno poboljšanje nosivosti i krutosti u odnosu na neojačani nosač. Eksperimentalni program je obuhvatio izradu i ispitivanje na savijanje neojačanih i ojačanih nosača. Svi nosači su ispitani do loma. Mehaničke karakteristike ojačanih nosača su upoređene sa karakteristikama neojačanih nosača sa aspekta veze opterećenje-ugib, oblika loma, nosivosti, krutosti i raspodele dilatacija u preseku. Ostvarivanje spoja lepljenjem je široko prihvaćeno kao efikasan metod za ravnomerno prenošenje opterećenja između konstrukcijskih materijala i generalno se smatra kao najpogodnija tehnika povezivanja FRP materijala i drveta. Kvalitativna procena karakteristika spoja između drveta, epoksidnog lepka i karbonske trake sprovedena je posebnim ispitivanjem. Program ispitivanja materijala je, takođe, sproveden, sa ciljem određivanja mehaničkih karakteristika drveta i CFRP materijala, koje mogu biti korišćene kao ulazni podaci za analitičku i numeričku analizu. Analitički model za predviđanje nosivosti i krutosti ojačanih nosača je predložen. Model je kalibrisan na osnovu dobijenih rezultata ispitivanja neojačanih nosača, a zatim modifikovan kako bi se uzeo u obzir efekat karbonskog ojačanja. Trodimenzionalni nelinearni numerički model je razvijen da simulira ponašanje neojačanih i ojačanih nosača. Simuliranje je izvršeno primenom metode konačnih elemenata, korišćenjem programa ABAQUS. Model se može lako prilagoditi različitim geometrijama i karakteristikama materijala i kao takav predstavlja koristan alat za optimalizaciju projektovanja ojačanih nosača. Na osnovu rezultata istraživanja, moguće je zaključiti da primena karbonskih traka predstavlja povoljno rešenje za ojačanje (sanaciju) lepljenih lameliranih drvenih nosača. Strateško postavljanje karbonskog ojačanja u zonu najvećih napona zatezanja nosača može dovesti do značajnog poboljšanja nosivosti i krutosti, kao i duktilnosti.

The idea of reinforcing glued laminated timber (glulam) beams came in response to the need to improve the mechanical properties, as well as to ensure higher reliability of this type of structural elements. In the last decade the use of fiber reinforced polymers (FRPs) in the context of strengthening and repairing structures has been significantly increased. Properties such as light weight, high stiffness and tensile strength, corrosion resistance and wide variety of available sizes and shapes are some of the reasons that justify the growing use of this type of materials. Although extensive research has been conducted for concrete and masonry members reinforced with FRP composites, very limited information is available for timber applications. This thesis investigated the possibility of using carbon fiber reinforced polymer (CFRP) plates as reinforcement of glulam beams. Experimental, analytical and numerical approaches are employed in order to assess the effect of the reinforcement on flexural behavior of beams. The main focus of this thesis had been on identifying an optimum reinforcement arrangement which maximizes the stiffness/strength properties. The experimental test program involved the fabrication and testing in flexure of unreinforced beams and reinforced beams. All of the beams were tested to failure to examine their behavior and determine the effect of various reinforcing schemes. The mechanical performance of the reinforced beams is compared with that of the unreinforced glulam beams with regard to the load-deflection behavior, failure mode, ultimate load capacity, stiffness and strain profile distribution. Adhesive bonding is widely recognized as an effective method for uniformly transferring the shear stresses between structural materials and is generally considered the most effective technique for connecting reinforcing FRP material and timber. Characterization of the bond performance between the timber, epoxy adhesive and CFRP plates was undertaken. A program of material characterization studies was, also, undertaken to determine mechanical properties for the timber and CFRP which could be used as input data for the analytical and numerical models. An analytical model is proposed to predict the flexural capacity and stiffness of reinforced glulam beams. The model is calibrated using the results of the unreinforced timber beam tests and modified to account for the effect of the CFRP reinforcement. A 3D non-linear numerical model was developed to simulate the behavior of unreinforced and reinforced beams. The finite element package ABAQUS was employed for the simulations. The model can readily accommodate different geometries and material properties, and is therefore a useful tool to optimize the design of the CFRP reinforced glulam beams. Based on the results of the study, it is possible to conclude that the application of CFRP plates is a promising solution to reinforce (repair) the glulam beams. Strategically positioned the CFRP reinforcement in the more highly stressed tension region at of the glulam beam may produce significant improvements in strength and stiffness, as well as ductility.

Podzemni vodonosni sloj kao sezonski termički rezervoar toplotne pumpe

Aquifer as seasonal thermal reservoir of the ground source heat pump

Istraživanja u okviru ove doktorske disertacije posvećena su izučavanju problema prostiranja toplote u podzemnom vodonosnom sloju, tokom jednogodišnjeg rada otvorenog sistema geotermalne toplotne pumpe (GTP), kako pri kontinualnom, tako i pri cikličnom, radnom režimu, kao i njihovoj uporednoj analizi. Istraživanja su sprovedena pomoću numeričkog modeliranja. Novoformiranim numeričko-matematičkim modelom obuhvaćena su dejstava čiji uticaj na temperaturno polje u podzemnom vodonosnom sloju do sada nije detaljno proučavan: trodimenzionalnost razvoja temperaturnog polja, brzina strujanja podzemnih voda, kao i uticaj slojevite heterogenosti vodonosnog sloja. Istovremeno, numeričkim modelom obuhvaćen je i uticaj rastojanja između bunara, kao i položaj povratnog bunara u odnosu na crpni bunar - nizvodan ili uzvodan. Provera tačnosti numeričkog modela izvršena je sa dva aspekta. Prvi, sopstvenim eksperimentalnim ispitivanjima - merenjem temperaturnog polja koje se formira u podzemnom vodonosnom sloju laboratorijskog modela otvorenog sistema GTP i poređenjem sa odgovarajućim vrednostima temperature dobijenim na osnovu numeričkih simulacija. Drugi aspekt predstavljaju eksperimentalni podaci drugih autora. Uz zadržavanje nepromenjenog sistema modeliranih jednačina, koji definišu neustaljeno strujanje nestišljivog fluida kroz homogenu i izotropnu zasićenu poroznu sredinu, numerički model je korigovan u delu graničnih uslova, tako da bude usklađen za simulaciju rada sistema geotermalne toplotne pumpe sa 2 crpna i 3 povratna bunara, kao i za slučaj određivanja dvodimenzionalnog ustaljenog temperaturnog polja pri prinudnom horizontalnom strujanju vode u zasićenoj poroznoj sredini sa vertikalnom temperaturskom razlikom. Iz uporednog prikaza i analize eksperimentalnih i rezultata dobijenih numeričkom simulacijom, uočen je ii visok stepen njihovog slaganja, čime je potvrđena pouzdanost i primenljivost formiranog numeričkog modela. Analizom dobijenih rezultata pokazano je da mnogo značajniji uticaj na pouzdanost predviđanja numeričkog modela ima poznavanje tačnih vrednosti termofizičkih karakteristika čvrste faze podzemnog vodonosnog sloja, nego uvedene ograničavajuće pretpostavke pod kojima je numerički model izveden: laminarnost toka podzemne vode, pretpostavka homogene, izotropne i potpuno zasićene porozne sredine za podzemni vodonosni sloj, trenutno ujednačavanje temperature podzemnih voda i čvrstih čestica, zanemarivanje uticaja efekata disperzije, kao i konduktivnih toplotnih gubitaka u slojevima iznad i ispod vodonosnog sloja.

Research in the framework of the doctoral dissertation is devoted to the study of the heat transfer in the underground aquifer during the one-year operation of the open- loop ground source heat pump system (GSHP), both in the continuous and cyclical working regime, as well as in their comparative analysis. The research was carried out using numerical modelling. The newly formed numerical-mathematical model includes effects whose influence on the aquifer temperature field has not been studied in detail until now: three-dimensional development of the temperature field, the velocity of underground water flows, and the influence of the layered aquifer heterogeneity. At the same time, the numerical model also includes the influence of the distance between the wells, as well as the position of the return well relative to the pumping well - downstream or upstream. The verification of the accuracy of the numerical model was done in two aspects. First, by its own experimental tests - by measuring the temperature field formed in the aquifer оf the open-loop GSHP laboratory model and by their comparison with the corresponding temperature values obtained on the basis of numerical simulations. The second aspect is the experimental data of the other authors. With the retaining of the unchanged system of modelled equations, that define the unsteady flow of incompressible fluid through a homogeneous and isotropic saturated porous medium, the numerical model has been corrected in part of the boundary conditions, so that it is coordinated for the simulation of the geothermal heat pump system operation with 2 pumping and 3 injection wells, as well as in the case of determining two-dimensional steady state temperature field during forced horizontal flow of water in saturated porous medium with vertical temperature difference. According to comparative presentation and analysis of experimental results and results obtained by numerical simulation, a high degree of their agreement was observed, which confirmed the reliability and applicability of the formed numerical model. iv The analysis of the obtained results showed that a much more significant influence on the reliability of the numerical model prediction has the knowledge of the exact values of the aquifer solid phase thermophysical characteristics, than the introduced limiting assumptions under which the numerical model is derived: laminar flow of groundwater, the assumption of a homogeneous, isotropic and fully saturated porous medium for the aquifer, the current equilibrium of the groundwater and solid particles, neglecting the dispersion effects, as well as the conductive heat losses in layers above and below the aquifer.

Demografska heterogenost pograničnog prostora Srbije - polazište javnih politika

Demographic heterogeneity of Serbian border region - origin of public policy

Ispitivanje pograničnog prostora ima dugu tradiciju. Na osnovu bogate naučne literature uočava se evolucija u istraživanju ovog prostora, a težište proučavanja se tokom vremena premešta sa geografskog, geostrateškog i geopolitičkog aspekta na demografske, ekonomske, socijalne, etničko-političke i ostale sfere istraživanja. Pogranične opštine u istočnom delu Srbije najpre su se suočile sa problemom depopulacije početkom šezdesetih godina prošlog veka, a naredne decenije su se suočile sa problemom emigracije stanovništva. Iako su se ovi procesi kasnije proširili na ostale opštine Srbije, pogranični prostor je prvi apostrofiran kao prostor koji se suočava sa demografskim problemima. Tome je u velikoj meri doprineo i pogranični položaj, jer je tokom prošlog veka, usled centralističkog modela države, blizina granice uticala na povećanje barijernosti i izolacije pograničnih opština, što je u kombinaciji sa često nepovoljnim geografskim, i time uslovljenim saobraćajnim položajem, imalo negativnih uticaja na razvoj ovog strateški značajnog područja. Ovi faktori i demografski trendovi uticali su na stvaranje stereotipa da su pogranične opštine periferne, nerazvijene, zaostale u ekonomskom razvoju i suočene sa brojnim demografskim problemima. Neophodnost detaljnog demografskog istraživanja pograničnog prostora Srbije proistekla je iz činjenice da su se tokom druge polovine 20. veka i početkom 21. veka odigrale krupne društvene promene. Politička dešavanja tokom devedesetih godina uticala su na promene granica, čime je promenjen pogranični prostor Srbije. Opštine koje su nekada bile centralne dobile su pogranični status. Otuda možemo reći da postoje stare i nove granice, što je u velikoj meri uticalo na diferenciranost pograničnog prostora Srbije. Za razliku od starih pograničnih opština, koje su se sa demografskim problemima počele suočavati šezdesetih godina prošlog veka, period sticanja pograničnog položaja je značio početak demografskih problema za većinu novih pograničnih opština. Polazeći od pretpostavke da je vreme formiranja granice uticalo na razvoj pograničnih opština pošli smo od činjenice da su pogranične opštine međusobno heterogene. Ovaj rad nudi širok metodološki aparat za utvrđivanje demografske heterogenosti pograničnih krajeva. Analizom su poljuljane pretpostavke da su sve pogranične opštine izolovane, i donekle osporena uvrežena shvatanja da je celokupan pogranični prostor nerazvijen i demografski devastiran. Obilje materijala o regionalnim razlikama, diferencijalnom prirodnom i migracionom kretanju stanovništva, i demografskim strukturama otkriva da su pogranične opštine međusobno značajno heterogene, što je uslovljeno brojnim faktorima. To nas dovodi do pitanja da li su sve pogranične opštine periferne, ili se među njima izdvajaju opštine sa povoljnijim razvojnim mogućnostima, kao i opštine koje se nalaze na margini društva. Ovaj rad nudi teorijska razmatranja problema perifernosti, inspirisana teorijama polarizovanog razvoja, a sve u cilju analize heterogenosti pograničnih opština i utvrđivanja nivoa perifernosti pograničnih opština. Krajnji cilj ove analize jeste istraživanje demografske heterogenosti pograničnih opština u funkciji javnih politika i ukazivanje na moguće pravce razvoja ovih opština. Možemo reći da ovo istraživanje ima teorijski doprinos teorijama o perifernosti i marginalnosti, definisanjem ovih pojmova i odabirom kriterijuma za njihovo određivanje i stepenovanje. A demografske smernice do kojih smo došli su značajne za kreiranje populacione politike pograničnih opština, te možemo reći da ovo istraživanje ima i aplikativan, društveno primenljiv značaj.

Examination of the Serbian border area has a long tradition. Based on a rich scientific literature it can be seen evolution in the exploration of this space, and the focus of study over time is shifted from geographical, geostrategic and geopolitical aspects to demographic, economic, social, ethnic-political and other spheres of research. Border municipalities in the eastern part of Serbia first faced the problem of depopulation in the early sixties, and in the following decade, they faced the problem of emigration of the population. Although these processes later expanded to other municipalities of Serbia, the frontier area is the first apostrophe as a space that faces demographic problems. This was also greatly influenced by the border position, because over the past century, due to the centralist model of the state, the proximity of the border influenced the increase in the barrier and isolation of border municipalities, which is combined with often unfavorable geographical and traffic situation, had a negative impact on the development of this strategically important area. These factors and demographic trends have influenced the creation of stereotypes that border municipalities are peripheral, underdeveloped, lagging behind in economic development and facing numerous demographic problems. The necessity for a detailed demographic survey of the border area of Serbia stemmed from the fact that during the second half of the 20th century and the beginning of the 21st century major social changes took place. Political developments during the 1990s influenced the change of borders, which changed the border area of Serbia. Municipalities that were central received a border status. Hence we can say that there are old and new borders, which greatly influenced the differentiation of the border area of Serbia. Unlike the old border municipalities, which faced demographic problems in the sixties of the last century, the period of acquisition of the border position was the beginning of demographic problems for most of the new border municipalities. Starting from the assumption that the timing of border formation has influenced the development of border municipalities, we have come from the fact that border municipalities are heterogeneous. This paper offers a wide methodological apparatus for determining the demographic heterogeneity of the border regions. The analysis has shaken the assumptions that all border municipalities are isolated, and the insights that border area is underdeveloped and demographically devastated are disputed. The abundance of materials on regional differences, differential natural and migration flows of the population, and demographic structures reveal that border municipalities are mutually significant heterogeneous, which is conditioned by numerous factors. This leads us to the question of whether all border municipalities are peripheral, or among them are the municipalities with more favorable development opportunities, as well as the municipalities that are at the margin of the society. This paper offers theoretical considerations of the problem of peripherality, inspired by theories of polarized development, with the aim of analyzing the heterogeneity of border municipalities and determining the level of peripherality of border municipalities. The ultimate goal of this analysis is investigation the demographic heterogeneity of border municipalities in the function of public policies and point to the possible directions for the development of these municipalities. We can say that this research has a theoretical contribution to the theories of peripherality and marginality, defining these terms and select the criteria for their determination and staging. And the demographic guidelines that we have come up with are important for creating a population policy of border municipalities, and we can say that this research has an applied, socially applicable character.

Teorijsko i eksperimentalno istraživanje gubitaka sile prednaprezanja u visokovrednim zavrtnjevima

Theoretical and experimental research of losses of pretension force in high strength bolts

Tarni spojevi sa prednapregnutim zavrtnjevima imaju veliki značaj u oblasti čeličnih konstrukcija, posebno u slučajevima konstrukcija izloženenih dejstvu dinamičkog opterećenja, kao što su mostovi, kranski nosači, stubovi vetro generatora, itd. Dva parametra koji imaju najveći uticaj na nosivost ovakvih spojeva su koeficijent trenja na tarnim površima i ostvarena sila prednaprezanja u visokovrednim zavrtnjevima. Potreba da se prate savremeni trendovi u građevinarstvu, posebno sa aspekta novih materijala, rezultovala je ispitivanjem spojeva, u okviru ovog istraživanja, koji su antikoroziono zaštićeni savremenim cink-silikatnim premazima. Korišćen je komercijalni premaz „Resist 86“, proizvođača „Jotun“ iz Norveške. Veze su ostvarene uz pomoć klasičnih HV visokovrednih zavrtnjeva, ali i uz pomoć, u građevinarstvu sve češće primenjivanih, zavrtnjeva sa zaključavanjem tipa „Huck BobTail (HBT)“, proizvođača „Alcoa Fastening Systems“ iz Engleske. Na ovaj način, klasičan postupak zaštite tarnih površina metalizacijom zamenjuje se jeftinijim, jednostavnijim i bržim postupkom nanošenja premaza. Takođe, ispitivana je i opravdanost primene zavrtnjeva sa zaključavanjem u poređenju sa klasičnim pregnapregnutim zavrtnjevima. Međutim, primena novog materijala kao antikorozione zaštite tarnih površina otvara pitanje gubitaka sile prednaprezanja u zavrtnjevima jer je opšte poznato da dominantan deo ovih gubitaka potiče od promene debljine sloja antikorozione zaštite kroz vreme. Sprovedeno istraživanje ima dva osnovna cilja: da proveri opravdanost primene predmetnog premaza u tarnim spojevima, sa stanovišta ostvarenog koeficijenta trenja i sa stanovišta gubitaka sile prednaprezanja. Sprovedena su sopstvena eksperimentalna istraživanja i ispitano je 126 zavrtnjeva u okviru 42 uzorka spojeva sa dvostrukim preklopom. Eksperimentalno istraživanje je zbog svog obima i raznolikosti podeljeno u nekoliko faza: - Određivanje fizičko-mehaničkih svojstava primenjenih materijala. Ova faza podrazumeva određivanje koeficijenta trenja koji se ostvaruje primenom predmetnog cink silikatnog premaza kao i fizičko mehaničkih svojstava (granice razvlačenja i zatezne čvrstoće) materijala od kog su izrađeni primenjeni HV i HBT zavrtnjevi; - Određivanje debljine nanetog premaza na svaku od čeličnih ploča od kojih su formirani uzorci; - Kalibracija sile u zavrtnjeva. Kao najracionalniji ali i najefikasniji način za merenje sile u zavrtnju izabran je postupak ugradnje mernih traka u telo zavrtnjeva. Nakon ugradnje mernih traka, a pre ugradnje zavrtnjeva u uzorke, izvršena je njihova kalibracija i tako uspostavljena veza između promene dužine zavrtnja (merne trake) i sile u zavrtnju. Neki dragoceni zaključci o raspodeli sile unutar zavrnjeva su izvedeni na bazi ovih rezultata. - Centralni deo istraživanja u kojem je izvršeno kontinuirano praćenje promene sile u zavrtnjevima i to 60 nedelja za prvo ugrađenih 36 zavrtnjeva, odnosno 24 nedelje za preostalih 72 zavrtnja i - Ispitivanje 6 uzoraka (18 zavrtnjeva) na dejstvo dinamičkog opterećenja tokom 2x106 ciklusa. Uzorci su formirani na način da se obezbedi variranje: vrste zavrtnja (HV i HBT), dužine zavrtnja preko različite debljine steznog paketa (18 mm, 35 mm i 55 mm), debljine premaza (uzorci sa i bez premaza) i vrste opterećenja uzorka (bez spoljašnjeg opterećenja na uzorke i uzorci izloženi dejstvu dinamičkog opterećenja). Dobijeni rezultati potvrđuju opravdanost primene predmetnog premaza u tarnim spojevima, sa obzirom da su određeni koeficijenti trenja u intervalu 0,40-0,50. Takođe, za svaku grupu zavrtnjeva određeni su inicijalni, kratkoročni i dugoročni gubici sile prednaprezanja. Ekstrapolacijom rezultata sakupljenih u prve 24 nedelje na period od 20 godina, za svaki tip i dužinu zavrtnja, definisana je kriva koja opisuje promenu sile prednaprezanja u zavrtnju u posmatranom periodu. Od svih ispitivanih zavrtnjeva jedino kod najkraćih HBT zavrtnjeva (dužine 55 mm) uočen je problem ostvarivanja proračunske sile prednaprezanja. Kod zavrtnjeva ugrađenih u uzorke sa antikorozionom zaštitom gubici sile prednaprezanja značajno su veći od onih koji su ugrađeni u uzorke bez antikorozione zaštite. Uticaj dinamičkog opterećenja, definisanog tako da ne dovede do proklizavanja veze niti plastifikacije bilo kog njenog dela, može se zanemariti sa aspekta gubitaka sile prednaprezanja. Takođe, može se zaključiti da je gubitak sile prednaprezanja najveći kod najkraćih zavrtnjeva i da opada sa povećanjem dužine zavrtnjeva. Primenom metode konačnih elemenata (MKE) modifikovani su postojeći izrazi za fleksibilnost HV zavrtnjeva i definisani novi za HBT zavrtnjeve. Takođe, primenom rezultata MKE i sopstvenog eksperimentalnog istraživanja, određena su reološka svojstva primenjenog cink-silikatnog premaza. Na osnovu rezultata sprovedenog istraživanja zaključuje se da je primena predmetnih premaza kao i upotreba ispitivanih HBT zavrtnjeva u tarnim spojevima moguća. Takođe, izvršena kvantifikacija gubitaka sile prednaprezanja omogućava projektantima da ih u postupku projektovanja uzmu u obzir i tako spreče gubitak nosivosti usled proklizavanja.

Friction connections with high-strength pretension bolts are greatly important in the field of steel structures, especially in structures imposed to dynamic loads, such as bridges, cranes and wind turbine towers. Two parameters mostly influencing the load- bearing capacity of such connections are the friction coefficient on friction surfaces and the achieved pretension force in high-strength bolts. In an effort to meet contemporary trends in the field of structural engineering, especially by usage of new materials, connections with state-of-the-art zinc-rich silicate based coating as an anti-corrosive primer have been investigated in the scope of this research. Such a commercial coating „Resist 86“, manufacturer by „Jotun“ in Norway, is used. Friction connections are formed using classical HV high-strength bolts but also the lock-bolts „Huck BobTail (HBT)“, manufactured by „Alcoa Fastening Systems“ in England, which are more and more frequently used in the field of structural engineering. In this way a classical procedure of providing metalized friction surfaces is replaced with much cheaper, more simple and quicker coating process. At the same time lock- bolts are analysed in terms of their applicability when compared to the classical pretension bolts in use. On the other hand, application of the new material, which acts as anti-corrosion protection over friction surfaces, stirs debate with regards to pretension force loss in bolts as it is a commonly known fact that the dominant portion of these losses stems from a change in anti-corrosion layer thickness which may emerge in time. The research in question strives at two principle goals: whether usage the coating in question in tension connections is justified from the standpoint of achieved friction coefficient and from the standpoint of loss of the pretension force. Related experimental research has been conducted in which 126 bolts were tested within 42 double-lap joint specimens. The experimental works are divided into several phases due to their large extent and variety: - Determination of physical and mechanical properties of the applied materials. This phase implies testing of friction coefficient which is achieved by applying the aforementioned zinc-based silicate coating, and the mechanical properties (yield strength and tensile strength) of the HV and HBT bolts materials; - Measuring the thickness of the coating applied to all the steel plates used to from the specimens; - Bolt force calibration. Bolt force measurement procedure relating to insertion of strain gauges into the bolts has been selected as the most rational and efficient one. After the strain gauges are fitted, and prior to assembling the bolts into the specimens, bolt force is calibrated in means of determination of force-strain relation for each bolt. Some significant conclusions about distribution of the force in the bolt have been drawn relaying on these results. - The focal point of the research - continuous monitoring the changes in bolt forces has been carried out over 60 weeks for the first batch of 36 bolts, and over 24 weeks for the remaining 72 bolts; - Testing of 6 specimens (18 bolts) for dynamic loads in 2x106 cycles. Specimens have been formed in a way to allow variation of: bolt types (HV and HBT), bolt lengths for various clamping package thicknesses (18 mm, 35 mm and 55 mm), coating thickness (with and without coating) and loading conditions (with no external load sustained by samples and samples exposed to dynamic loads). The obtained results justify the application of the investigated coating type in friction connections given that friction coefficients are in range of 0,40-0,50. In addition, initial short-term and long-term pretension force losses have been determined for each group of bolts. Results obtained within the first 24 weeks are extrapolated to period of 20 years where a curve which describes change in pretension force within time was defined for each bolt type and bolt length separately. The shortest HBT bolts (55 mm long) showed to be problematic with regards to achieving the design value of pretension force. Pretension force losses are significant in bolts assembled to specimens with the coating when compared to those without. Influence of the dynamic loads, which are below slip resistance of the connection, can be disregarded in means of loss of the pretension force. Additionally, the conclusion can be drawn that the pretension force loss is the largest in the case of shortest bolts and that it can be reduced by increasing the bolt length. Using finite element method (FEM) for modelling the experiments of calibration process of HV and HBT bolts, existing equations for flexibility of HV bolts are improved, and for the first time equations are defined for HBT bolts. Also, using the results of FEM and experimental research, rheological properties of the applied zinc-silicate coating are determined. According to results obtained from the conducted research, application of aforementioned coatings can be recommended, as well as the use of tested HBT bolts in friction connections. Quantification of pretension force loss allows for the engineers in practice to take such data into consideration in the course of design development and prevention of overestimation of load-bearing capacity against slippage.

Elastoplastična analiza rešetkastih nosača sa oštećenjem pri cikličnom opterećenju

Elastoplastic damage analysis of trusses subjected to cyclic loading

U ovoj doktorskoj disertaciji je razmatrano ponašanje rešetkastih konstrukcija u plastičnoj oblasti sa ciljem da se optimizuje numerička analiza ovog problema i da se definiše osnova za proširivanje odgovarajućeg modela na gredne elemente linijskih nosača. Ovaj problem, pri cikličnom opterećenju, dobija novu dimenziju u pogledu tačnosti rezultata nakon određenog broja ciklusa, kao i u pogledu numeričke zahtevnosti odgovarajućeg modela. Model materijala zasnovan na Prajzakovom (Preisach) histerezisnom operatoru, određen kao analitički izraz za vezu napon-deformacija, omogućava numerički efektno modeliranje jednoaksijalnog ponašanja materijala. Koristeći ovaj model, u ovoj disertaciji su definisane jednačine u metodi konačnih elemenata za elastoplastičnu analizu rešetkastih nosača pri cikličnom opterećenju i na osnovu toga je definisan algoritam za proračun u programskom jeziku c++. Za validaciju rezultata i analizu numeričkih karakteristika proračuna zasnovanog na modelu materijala koji je korišćen u disertaciji, u numeričkim primerima su poređeni rezultati dobijeni predmetnim modelom sa rezultatima dobijenim koristeći drugi histerezisni operator (Bouc-Wen) i rezultatima dobijenim koristeći jedan od klasičnih modela plastičnosti (model generalisane plastičnosti). Geometrijska nelinearnost je uzeta u obzir poznatim metodama i definisana u delu numeričkih primera. Stanje napona u materijalu koji se analizira je jednoaksijalno, a u numeričkim primerima sa grednim elementima je usvojena hipoteza o ravnim presecima. Pored postojećeg (Prajzakovog) modela za elastoplastično ponašanje materijala, u ovoj disertaciji je definisan model oštećenja u materijalu preko dva pristupa. U prvom pristupu, definisani histerezisni operator za elastoplastično ponašanje materijala je modifikovan kako bi mogao da modelira oštećenje u materijalu. U drugom pristupu, u definisani algoritam proračuna metode konačnih elemenata predmetnog modela elastoplastičnosti je uveden fenomen oštećenja korišćenjem osnovnih principa mehanike kontinuuma sa oštećenjem. Pored toga, predstavljen je model za proračun histerezisnog gubitka energije u rešetkastim konstrukcijama, zasnovan na predmetnom modelu, kao i osnova za proširenje analize na gredne nosače koristeći numeričku integraciju napona u poprečnom preseku za jednostavne slučajeve savijanja.

In this doctoral dissertation, behavior of trusses in plastic domain is investigated in order to optimize numerical analysis of this problem and to define foundation for extending proposed model to the analysis of beam elements. New dimension in this problem arise in the case of the cyclic loading, relating to the accuracy of results after certain number of cycles and computational effort of corresponding model. Material model based on the Preisach hysteretic operator, determined as analytical expression for stress-strain relation, enables numerically effective modeling of uniaxial material behavior. By using this model, in this dissertation, finite element equations for elastoplastic analysis of trusses subjected to cyclic loading are determined, which lead to definition of algorithm for numerical analysis in c++ programming language. In order to validate results and to analyze numerical performance of calculation based on the material model used in this dissertation, in numerical examples, results obtained by analyzed (Preisach) model are compared with results obtained by using other hysteretic operator (Bouc-Wen) and also with results obtained by using one of the classical model of plasticity (generalized plasticity model). Geometric nonlinearity is taken into account by well established methods, and it was defined in several numerical examples. Stress state in analyzed material is uniaxial, and in numerical examples with beam elements, the assumption of engineering beam theory is adopted (cross section is perpendicular to a bending line). Besides existing (Preisach) model for elastoplastic material behavior, in this dissertation damage model in material is defined through two approaches. In the first approach, proposed hysteretic operator for elastoplastic behavior is modified, so that it would have the possibility to model the damage in material. In the second approach, in proposed finite element algorithm for elastoplastic analysis, phenomenon of damage is introduced by using the basic principles of continuum damage mechanics. In addition, model for calculation of hysteretic energy loss in truss structures, based on the considered model, is presented, and finally, the foundation for extending the corresponding analysis on beam elements, by using numerical integration of normal stress in cross section, for simple cases of loading, is proposed.

Uticaj savremenih klimatskih kolebanja i potencijalnih promjena klime na fitogeografska obilježja Republike Srpske

The impact of recent climate variability and potential climate change on phytogeographic characteristics of the Republic of Srpska

Cilj disertacije je da determiniše uticaj savremenih kolebanja klime na fitogeografska obilježja Republike Srpske. Na osnovu podataka sa jedanaest meteoroloških stanica izvršena je analiza trendova najvažnijih klimatskih elemenata koji utiču na razvoj i rasprostranjenje biljnog svijeta, a prije svega temperature vazduha, padavina, vlažnosti vazduha, oblačnosti i insolacije. U periodu 1961‒2015. godine utvrđeni su pozitivni trendovi srednjih, maksimalnih i minimalnih godišnjih i sezonskih temperatura vazduha. Svi navedeni trendovi najizraženiji su u sjevernom dijelu Republike Srpske, dok je porast zagrijavanja nešto manji u višim područjima Hercegovine. Na cijeloj teritoriji utvrđen je značajan pozitivan trend sume aktivnih temperatura, kako na godišnjem nivou, tako i u vegetacionom periodu. Za razliku od temperature vazduha, trendovi padavina su, sezonski i regionalno, veoma promjenljivi i različitog znaka, ali nesignifikantni. Ipak, povećana je međugodišnja varijabilnost padavina i učestalost godina sa ekstremnim padavinama. Uočena savremena kolebanja klimatskih elemenata dovedena su u vezu sa promjenama fiziologije (tj. sa promjenama prirasta godova drveća i prinosa kultura) i pomjeranjima u fenologiji biljaka. Ustanovljeno je da je porast srednje godišnje temperature vazduha negativno uticao na debljinski prirast drveća. Utvrđena je značajna negativna korelacija između prirasta drveća i normalizovanog efekta gasova staklene bašte, kao i Atlantske višedecenijske oscilacije. Pomjeranja u fenologiji biljaka generalno se ogledaju u negativnim trendovima proljećnih fenofaza i pozitivnim trendovima jesenjih fenofaza. Na osnovu utvrđenih savremenih kolebanja klime i projekcija budućih promjena predložene su smjernice za ublažavanje klimatskih promjena i prilagođavanje na promijenjene klimatske uslove.

the phytogeographic characteristics of the Republic of Srpska. Based on data from eleven meteorological stations, trends in most important climate elements that affect plants development and distribution, primarily, air temperature, precipitation, humidity, cloud cover and sunshine, were determined. In the observed period (1961‒2015), the positive trends in mean, maximum and minimum annual and seasonal air temperatures were determined all over the Republic of Srpska. All the aforementioned trends are most pronounced in the northern part of the Republic of Srpska, while the warming increase is slightly lower in the higher areas of Herzegovina. In the observed period, over the entire territory of the Republic of Srpska a significant positive trend of active temperatures sums, both annual and in the growing season is determined. Unlike air temperature, precipitation trends are seasonally and regionally very variable and different in character, but all insignificant. Inter-annual precipitation variability as well as the frequency of years with extreme precipitation have increased. Recent variability of climatic elements, particularly air temperature and precipitation, has been brought into correlation with the changes in physiology (i. e. changes in tree-ring increment and crop yields) and in shifts in plants phenology in the Republic of Srpska. It was found that the increase in mean annual air temperature negatively affected the tree-ring diameter increment. There is a significant negative correlation between the tree-ring increment and normalized effect of greenhouse gases, as well as between the tree-ring increment and the Atlantic Multidecadal Oscillation. Shifts in seasonal plants activities, in general, are reflected in the negative trends of spring phenophases and positive trends of autumn phenophases. Based on the observed recent climate variability in the Republic of Srpska and projected future climate change, basic guidelines for mitigation and adaptation to changing climate are proposed.

Optimizacija građevinskih mera u cilju smanjenja potrebne energije za grejanje u stambenim zgradama

Optimization of construction measures for reducing heating energy demand in residential buildings

Sektor zgradarstva je najveći pojedinačni potrošač energije. Unapređenje energetske efikasnosti u zgradarstvu jedna je od najšire promovisanih mera za smanjenje eksploatacije neobnovljivih izvora energije i ublažavanje klimatskih promena kroz smanjenje emisije ugljen-dioksida. Ultimativni cilj treba da bude povećanje efikasnosti korišćenja energije i usporavanje rasta ukupne proizvedene energije, što zasigurno dovodi do ublažavanja klimatskih promena. Predmet istraživanja u ovoj disertaciji jeste energetska efikasnost u stambenim zgradama u delu koji se odnosi na smanjenje potrebne energije za grejanje. Uže gledano, predmet istraživanja su: (1) metode za proračun i procenu toplotnih gubitaka termičkog omotača zgrade u nestacionarnim uslovima prenosa toplote; i (2) višekriterijumski modeli za izbor i ocenu energetske efikasnosti građevinskih mera kod izgradnje novih ili energetske sanacije postojećih zgrada. Cilj istraživanja je bio da se definiše model koji bi davao podršku projekt menadžeru u procesu donošenja odluke vezane za izbor optimalnog rešenja pri izgradnji novih objekata ili rekonstrukciju postojećih, pri tome sagledavajući investicionu odluku sa više aspekata imajući u vidu i zahteve velikog broja zainteresovanih strana, kako u kratkoročnom tako i u dugoročnom periodu. U cilju ostvarenja postavljenog zadatka prvo je razvijen originalan precizan matematički model koji opisuje fizički proces razmene toplote između objekta i okoline, a koji dalje predstavlja osnov za pouzdan proračun troškova u periodu eksploatacije, definisanje mogućeg termalnog komfora u objektu kao i procenu uticaja objekta na životnu sredinu. S obzirom na postavljene ciljeve istraživanja, u disertaciji su prezentovana dva rezultata: (1) razvijen je novi pristup za određivanje svih relevantnih dinamičkih termičkih veličina koje služe za procenu prenosa toplote kroz građevinske elemente Zorana M. Petojević, dipl. građ. inž. netransparentnog dela fasade i ocenu toplotnog komfora u zgradama i (2) razvijen je višekriterijumski model za optimizaciju izbora građevinskih mera koji u sebi, pored energetskih, finansijskih i ekoloških parametara, sadrži i dinamičke termičke parametre kao kriterijume za ocenu toplotnog komfora u zgradama. Predloženi novi pristup za procenu prenosa toplote kroz građevinske elemente i ocenu toplotnog komfora u zgradama, predstavlja originalni naučni doprinos i sadrži sledeće korake: (1) postavka eksperimenta: osmišljena je specifična eksperimentalna tehnika za istovremeno in-situ merenje toplotnih flukseva i temperatura na površinama termičkog omotača zgrade, prema kojoj su sprovedena merenja tokom zimske sezone; (2) fizičko- matematički model: razvijen je diskretizovan fizičko-matematički model nestacionarnog prenosa toplote kroz višeslojne građevinske elemente nepoznate strukture i termičkih karakteristika i razvijena je tehnika rešavanja termalnog impulsnog odziva (engl. Thermal Impulse Response, TIR) sistema (modela) u vremenskom domenu; (3) validacija modela: dobijene TIR funkcije su proverene poređenjem rezultata modela sa podacima dobijenim iz drugog skupa merenja; (4) poređenje TIR funkcija sa analitičkim rešenjem: dodatno, izvršena je provera modela poređenjem dobijenih TIR funkcija sa izvedenim odgovarajućim analitičkim rešenjima za analizirani građevinski element poznate strukture i (5) praktična primena: razvijena je metodologija primene TIR funkcija na izračunavanje svih dinamičkih termičkih veličina. Razvijeni pristup za procenu TIR funkcija fasadnog zida zasniva se isključivo na podacima iz in-situ eksperimentalnih merenja površinskih temperatura i toplotnih flukseva na unutrašnjoj i spoljašnjoj površini zida u dinamičkom režimu. Merene veličine su povezane sa integralima konvolucije i funkcijama TIR-a. Rešavanjem inverznog problema koji je ill-posed, s obzirom da je sam sistem jednačina koji se rešava ill-posed, primenom metode najmanjeg kvadrata došlo se do TIR funkcija. Prema najboljim saznanjima autora, ovo je prvi pokušaj da se isključivo na osnovu in-situ merenja i korišćenjem tehnike dekonvolucije identifikuju TIR funkcije za višeslojan ravan zid sa nepoznatim termičkim svojstvima i strukturom, u dinamičkom režimu. Praktična primena predložene metode, u svrhu ocene energetskih performansi zgrade (EPB) i ocene energetske efikasnosti (EE), prikazana je kroz procenu kumulativnih toplotnih gubitaka predmetnog zida, akumulaciju toplote u zidu, procenu toplotnih Zorana M. Petojević, dipl. građ. inž. flukseva na površinama zida, kao procenu i svih njegovih dinamičkih termičkih karakteristika. U drugom delu disertacije razvijen je originalni hijerarhijski analitički optimizacioni model za izbor građevinskih mera u cilju smanjenja potrošnje energije u stambenim zgradama. Predloženi model izbor građevinskih mera sagledava kroz četiri parametra: 1) Energetski parametri; 2) Uslovi komfora; 3) Finansijski parametri i 4) Ekološki parametri, gde je za kvantifikaciju svakog od parametara predloženo 2-3 indikatora (ukupno 10 indikatora). Pored toplotnih gubitaka kroz omotač zgade i vrednosti koeficijenta prolaza toplote, kao do sada najčešće korišćenih indikatora energetske efikasnosti, predložni pristup podrazumeva uvođenje dinamičkih termičkih karakteristika zida (dekrement faktor i vremensko kašnjenje amplitude temperature) koji direktno odslikavaju toplotnu akumulativnost zida i nivo komfora u objektu. U cilju praćenja smanjenja korisne površine unutar objekta, za slučaj sanacije zida sa unutrašnje strane, ili eventualnog prelaska preko građevinske i/ili regulacione linije za novoprojektovane uslove kod sanacije spolja, uzeto je u razmatranje i povećanje debljine fasadnog zida. Predloženi indikatori finansijskih parametara su: 1) inicijalna investiciona sredstva, 2) ukupni troškovi u fazi eksploatacije i 3) povratni period investicionih sredstava. Ekološki parametri su procenjivani, kvantitativno (preko vrednosti za količinu emisije ugljen-dioksida koji se emituje u toku proizvodnje energije koju koristi objekat tokom eksploatacije), i kvalitativno (analizom i ocenom ugrađenih materijala sa aspekta ekologije). Razvijeni optimizacioni model ima prednost jer optimizaciju posmatra istovremeno kroz četiri najznačajnija aspekta energetske efikasnosti: 1) ekonomski aspekt, 2) potrošnja energije, 3) uticaj na životnu sredinu i 4) zadovoljenje uslova komfora, uzimajući u obzir potencijalne promene, naročito one vezane za uticaj inflacije i depresijaciju/apresijaciju novca tokom celog perioda eksploatacije objekta. Većina modela trenutno definisanih u svetskoj literaturi tretira najčešće samo dva aspekta istovremeno. Druga razlika i prednost predloženog modela je u tome što uvodi u razmatranje dinamičke termičke parametre zida i na taj način uzima u obzir toplotnu akumulativnost omotača zgrade kao i njegovu sposobnost da obezbedi toplotni komfor u vremenski promenljivim atmosferskim uslovima kakvi vladaju u okruženju objekta. Zorana M. Petojević, dipl. građ. inž. Na kraju disertacije izloženi su pravci daljih istraživanja koji se posebno odnose na: 1. razvoj složenih modela koji bi uzimali u obzir prisustvo linijskih i tačkastih gubitaka toplote u zidu ili nehomogenosti unutar zida koje čine da su temperaturska polja višedimenzionalna; 2. definisanje više različitih transfer funkcija koje odgovaraju različitim vrstama zidova, za različita godišnja doba: leto i zimu i različite starosti objekata; i 3. ispitivanje mogućnosti integracije ovih funkcija u softverska rešenja za detaljne dinamičke simulacije.

Building sector is the largest individual energy consumer. Increasing energy efficiency of buildings is one of the most widely promoted measure for reducing exploitation of non-renewable energy sources and mitigating climate changes through carbon dioxide emission reduction. The ultimate goal should be to increase the efficiency of energy use and the slowdown in overall energy produced, which certainly leads to climate change mitigation. The subject of research in this dissertation was energy efficiency in the residential building sector, in particular, the reduction of energy demand for heating. Narrowly seen, the subject of research was: (1) methods for calculating and estimating heat losses through the building’s thermal envelope in non-stationary conditions of heat transfer and (2) multi-criteria decision-making models for evaluating the energy efficiency of building construction measures for new or existing residential buildings. The aim of the research was to define a model that will support a decision-making process that project manager passes when making an optimal decision regarding the construction of new buildings or the refurbishment of old ones, respecting a large number of stakeholder requirements that project manager must deal with and considering many aspects of the investment in the short and long term. The task was to develop an original precise mathematical model describing the physical process of heat exchange between the building and the environment, which further provides the basis for a reliable calculation of the costs related to energy consumption incurred during the exploitation phase, the assessment of the achieved thermal comfort in the building as well as the assessment of the environmental impact of the building. Having in mind the stated research objectives, two resultes have been presented in the dissertation: (1) a novel approach has been developed for the determination of all Zorana M. Petojević, dipl. građ. inž. relevant dynamic thermal caracteristics used to estimate heat transfer through the opaque components of the building envelope in a dynamic regime and the assessment of thermal comfort in the building and (2) a multi-criteria decision-making model has been developed for the selection of optimal construction measures that, in addition to energy, financial and environmental parameters, implies the introduction of dynamic thermal parameters as criteria for assessing thermal comfort in buildings. The novel approach for the estimation of heat transfer through construction elements and the assessment of thermal comfort in buildings represents the original scientific contribution and consists of the following steps: (1) experiment set-up: a specific experimental technique for simultaneous in-situ measurement of heat fluxes and temperatures of the building wall surfaces was designed and data was recorded during the winter season (2) physical-mathematical model: a discretized physical-mathematical model of non-stationary heat transfer through multilayer building wall with unknown structure and thermal properties has been developed, and a technique for solving Thermal Impulse Response (TIR) of the thermal system in time domain has been developed; (3) validation of the model based on TIR: the obtained TIR functions were validated by using a separate set of in-situ experimentally obtained data through а comparison with the results of the model; (4) TIR comparison with the analytical solution: additionally, the obtained results for the TIR functions are compared with the results obtained by the analytical solution also derived in the dissertation for the known building envelope structure and properties; (5) practical application: the methodology for calculation of all dynamic parameters based on the estimated TIR functions has been developed. A novel approach for estimation of the TIR functions of a façade wall was based solely on data from in-situ experimental measurements of surface temperatures and thermal fluxes through inner and outer wall surfaces in a dynamic regime. The measured data were related by the convolution integrals and TIR functions. The TIRs were obtained using the Least Square (LS) estimator. Solving the inverse problem of identifying TIR functions is ill-posed, as the corresponding system of linear equations is ill-posed, by itself. To the best knowledge of the author, this is the first attempt to use the in-situ Zorana M. Petojević, dipl. građ. inž. measurements for identification of the TIR functions using de-convolution techniques of a multi-layer building wall with unknown thermal properties and structure. The practical applications of the proposed method related to the Energy Performance of Buildings (EPB) and Energy Efficiency (EE) were demonstrated by evaluation of cumulative heat losses, heat accumulation and heat fluxes at a building wall surfaces, as well as all dynamic thermal characteristics of a building component were evaluated. In the second part of the dissertation, an original hierarchical analytical optimization model for the selection of construction measures with the aim to reduce energy consumption in residential buildings was developed. The proposed model examines the selection of construction measures through four parameters: 1) Energy parameters; 2) Comfort requirements; 3) Financial parameters and 4) Ecological parameters, where 2-3 indicators were proposed for the quantification of each parameter. In addition to heat losses through the building envelope and the heat transfer coefficient value, as the most commonly used energy efficiency indicators, the proposed approach implies the introduction of dynamic thermal characteristics of the wall (the decrement factor and time lag of temperature amplitude) which directly reflect the rate of heat accumulation of the wall and the level of comfort in the building. With the aim of monitoring the reduction of the gross internal area, in the case of wall restoration from the inside or possible crossing over the building and/or street line for newly designed conditions, for external restorations, consideration was given to the increase in the thickness of the facade wall. The proposed financial parameter indicators were: 1) initial investment costs, 2) total costs during the exploitation phase, and 3) payback period on investment. The environmental parameters were estimated quantitatively (through the amount of carbon dioxide emitted during the energy production consumed during the facility exploitation), as well as qualitatively (through the analysis and evaluation of embedded materials from the environmental aspect). The main advantage of the proposed optimization model is that the problem of optimizing the energy efficiency of buildings was simultaneously examined through four most important aspects: 1) economic criteria, 2) energy consumption, 3) environmental loading, and 4) indoor thermal comfort, taking into account significant potential changes, especially due to inflation and currency depreciation/appreciation that Zorana M. Petojević, dipl. građ. inž. may occur during the whole period of the building operation. Most models, currently defined in world literature, treat simultaneously only two of the four aspects. Another difference and advantage is that the proposed model introduces into consideration the dynamic thermal parameters of the wall and thus takes into account the heat accumulation of the building envelope as well as its ability to provide the indoor thermal comfort in time-varying atmospheric conditions. The dissertation outlines the directions of further research particularly related to: 1. development of complex models that could be applied on non-linear problems taking into account linear heat losses in the wall or non-homogeneity within the wall that make the temperature fields multi-dimensional, 2. defining a wide range of transfer functions corresponding to different types of walls, for different seasons (summer and winter) and for different ages of facilities. 3. Testing the possibility of integrating these functions into software solutions for detailed dynamic simulations.

Teorijsko i eksperimentalno istraživanje graničnih trajektorija vožnje u vangradskim putnim krivinama

Theoretical and experimental research of the boundary vehicle paths in rural road curves.

Bezbednost putnog saobraćaja, usled velikog broja saobraćajnih nezgoda i izgubljenih ljudskih života, postala je jedan od najaktuelnijih problema savremenog društva. Da bi se dostigao i održao kontinuirani opadajući trend događanja saobraćajnih nezgoda, potrebno je problem bezbednosti posmatrati sa stanovišta interakcije vozača, vozila i okoline. Nameće se pitanje kako zahteve bezbednosti uključiti u proces planiranja i projektovanja puteva, što bi za posledicu imalo poboljšanje bezbednosti saobraćaja u celini. Dosadašnja istraživanja pokazala su da najvažnije informacije iz okoline vozaču pruža upravo put. Prema tim istraživanjima, najveći uticaj na vozača, kada donosi odluku o načinu vožnje i promeni stanja kretanja vozila, imaju pre svega elementi situacionog plana puta. U okviru ove teze, istražuje se veza radijusa horizontalnih putnih krivina, kao jednog od osnovnih elemenata situacionog plana, sa graničnim trajektorijama vožnje i maksimalnim voženim brzinama u tim krivinama. Akcenat je stavljen na istraživanje kretanja putničkih vozila u plitkim krivinama (malog skretnog ugla i radijusa manjeg od 250 m) u uslovima slobodnog saobraćajnog toka. Plitke krivine malog radijusa izdvojile su se kao posebno interesantne, uzimajući u obzir visok stepen saobraćajnih nezgoda koje se u njima događaju. Teorijsko, eksperimentalno i analitičko istraživanje korišćeni su u svrhu definisanja graničnih trajektorija vožnje kao i očekivanih brzina vožnje u datim krivinama. Teorijskom analizom analitički je definisan granični voženi radijus u krivinama. Analitički definisan izraz može se primeniti u početnim fazama projektovanja, čime se otvaraju mogućnosti za implementaciju realnih uslova vožnje u proces projektovanja puteva. Eksperimentalni program obuhvatio je merenja na deonicama vangradske putne mreže Srbije, u krivinama raspona radijusa od 110 do 250 m, u uslovima suvog i mokrog kolovoza. Među najvažnijim parametrima koji su mereni (posredno i neposredno), izdvaja se bočni položaj vozila u krivinama i trenutna brzina kretanja kroz krivinu. Ovi podaci omogućili su da se za svako pojedinačno vozilo definiše njegova trajektorija i brzina kretanja. Statističkom analizom određen je nazastupljeniji voženi radijus i očekivana brzina vožnje za svaku ispitivanu krivinu. Uporednom analizom rezultata merenja u uslovima suvog i mokrog kolovoza, istražena je i analitička veza između očekivanih brzina vožnje u uslovima suvog i mokrog kolovoza. Izvršena je i uporedna analiza graničnih trajektorija vožnje određenih eksperimentalnim putem sa analitički definisanim trajektorijama u teorijskoj analizi. Može se zaključiti da postoji poklapanje u vrednostima voženih radijusa dobijenih teorijski i eksperimentalno. Na osnovu rezultata istraživanja, moguće je zaključiti da postoji nesaglasnost voženog i projektovanog radijusa krivine. Usled toga, očekivana brzina u datim krivinama značajno je veća od teorijske (projektne) brzine na osnovu koje se put u datoj krivini u širem smislu projektuje (poprečni nagib, zahtevana preglednost, berma preglednosti). Procena očekivanih brzina vožnje i voženog radijusa u najranijim fazama projektovanja (pre svega idejnom projektu) smanjila bi posledice primene neadekvatne putne geometrije na postojećim putnim deonicama, ali bi, i inoviranjem i izmenama tehničke regulative, i sprečila njihovo nastajanje još u fazama projektovanja. Na osnovu sprovedenih istraživanja (teorijskih i eksperimentalnih) može se dati konkretan predlog za unapređenje i poboljšanje postojeće tehničke regulative kao i predlog daljih istraživanja neophodnih za generalizaciju navedenog problema.

Road safety, due to a large number of accidents and casualties, has become one of the most important issues of modern society. To achieve and maintain a continuous descending trend of traffic accidents, it is necessary to study the safety problem from the point of interaction of driver, vehicle and the environment (roadway). The question is how to include safety requirements in the road planning and design process, in a way that would result in the improvement of road safety in broader sense. Previous studies have shown that the most important information perceived by the driver is provided by the road itself. According to these studies, the utmost effect on the driver, when making a decision about how to drive, is made by the elements of road horizontal alignment. This thesis investigates the relation between radius of horizontal curve, as a basic element of horizontal alignment, on one side, and vehicle path and maximum spot speed in the curve, on another side. The emphasis is on the research of a passenger vehicle negotiating the shallow horizontal curve (with a small deflection angle and a radius less than 250 m) in free traffic flow conditions. The shallow curves are set aside to be particularly interesting, taking into account the high rate of road accidents that occur in them. Theoretical, experimental and analytical studies were used to define the vehicle path in curves, as well as the operating speeds (85th percentile free flow passenger vehicle speed) in the given curves. At first, the vehicle path radius was defined based on the theoretical analysis. The theoretical model in concern can be used in the early stages of the design process, thus opening opportunities for the implementation of real driving conditions in the road design stage. The experimental part of the thesis included the measurements on test sites of the two- lane rural road network in Serbia, in curve radii range from 110 to 250 m, under dry and wet road surface conditions. Among the most important parameters that were collected (directly and indirectly), the lateral position of the vehicle and the vehicle spot speed negotiating the curve, stood out as particularly important. The data collected enabled the definition of vehicle path and spot speed for each individual vehicle. Statistical analysis was used to determine the most common vehicle path radius and the operating speed for each tested curve. The approximate analytical relationship between the operating vehicle speeds under dry and wet road surface conditions was established on the basis of a comparative analysis of the data collected under the both road surface conditions. A comparative analysis of the vehicle path resulting from the experimental research, with analytical vehicle path defined in the theoretical analysis, was conducted as well. It can be concluded that a strong relationship exists between the path resulting from the experimental research with theoretically defined path. On the basis of these results, it can be concluded that there is a significant difference between vehicle path radius and designed curve radius values. As a result, the operating speed at which vehicle negotiates the curve is significantly higher than the theoretical speed (variable design speed Vvd) which serves for fine adjustments of the road elements (pavement cross grade, required sight distance, obstruction free zones). Evaluation of the operating speed and vehicle path radius in the earliest stages of the design (especially the preliminary design) would mitigate the consequences of an inadequate road geometry. In addition, with innovation of relevant technical policies and guidelines, the introduction of the realistic “vehicle path – spot speed” concept would enhance the road safety as early as in the design stage. Based on the research conducted (theoretical and experimental), enhancement and improvement of existing technical regulations are suggested, and further research on more test sites is recommended, thus providing a basis for more reliable generalization of conclusions and recommendations.

Formulacija i implementacija konstitutivnog modela za prekonsolidovane gline

Formulation and Implentation of Constitutive Model for Overconsolidated Clays

Pouzdanost analiza geotehničkih problema numeričkim metodama kao što su metoda konačnih elemenata ili metoda konačnih razlika, u velikoj meri zavisi od mogućnosti konstitutivnog modela da adekvatno opiše mehaničko ponašanje tla. Razvoj naprednih, ali sa druge strane, za upotrebu dovoljno jednostavnih konstitutivnih modela za tlo je neophodan uslov za racionalno projektovanje geotehničkih konstrukcija. Imajući u vidu da je za praktičnu primenu konstitutivnih modela imperativ jednostavna formulacija i jasno fizičko značenje parametara modela, formiran je HASP (HArdening State Parameter) model za opisivanje mehaničkog ponašanja prekonsolidovanih glina, koristeći teoriju kritičnog stanja i koncept granične površi. HASP model na jednostavan način prevazilazi mnoge nedostatke Modifikovanog Cam Clay modela, bez uvođenja dodatnih materijalnih parametara. Formulacijom zakona ojačanja u funkciji parametra stanja i stepena prekonsolidacije, omogućeno je opisivanje brojnih elemenata mehaničkog ponašanja prekonsolidovanih glina. U nedreniranim uslovima, model dobro opisuje generalnu formu putanje efektivnih napona u zavisnosti od stepena prekonsolidacije, kao i veličinu pornog pritiska. U dreniranim uslovima, model predviđa postepen prelaz iz kontrakcije u ekspanziju pre nego što je dostignuta vršna smičuća čvrstoća, kao i postepen prelaz iz ojačanja u omekšanje bez dodatnog matematičkog opisivanja. Naponska tačka se uvek nalazi na površi tečenja i na taj način je omogućeno elasto-plastično ponašanje još u ranim fazama opterećivanja. Za normalno konsolidovane gline, HASP model prelazi u Modifikovani Cam Clay model. Validacija modela je izvršena kroz poređenje sa publikovanim rezultatima dreniranih i nedreniranih opita triaksijalne kompresije i ekstenzije na širokom spektru prekonsolidovanih glina. HASP model je implementiran u ABAQUS/Standard koristeći korisnički potprogram UMAT i Metodu vodećeg parametra za numeričku integraciju konstitutivnih relacija modela. Kao vodeći parametar u algoritmu integracije usvojen je srednji efektivni napon. Mogućnosti HASP modela da adekvatno predvidi ponašanje prekonsolidovanih glina, ispitane su kroz analizu graničnog (konturnog) problema metodom konačnih elemenata. Razmatran je problem sleganja tla usled fazne izgradnje nasipa na površini prekonsolidovane gline, za različite stepene prekonsolidacije.

Accuracy and reliability of geotechnical analysis by numerical methods such as finite element method or finite difference method are significantly dependent on the ability of the constitutive model to describe the mechanical behavior of the soil in a proper manner. The development of advanced, but at the same time, for the use in engineering practise simple constitutive model for soil is essential for the rational design of the geotechnical structures. Bearing in mind that simple expressions and clear physical meaning of the model parameters are an imperative for practical application of constitutive models, the Hardening State Parameter model (HASP) for describing mechanical behaviour of overconsolidated clays is developed on the basis of the critical state theory and within the concept of bounding surface plasticity. The HASP model overcomes many deficiencies of the Modified Cam Clay model and at the same time it retains the same simplicity and the same set of parameters. With the state parameter and the degree of overconsolidation as the state variables a novel form of the hardening rule was proposed and it is possible to describe a number of elements of the mechanical behavior of overconsolidated clays. In undrained conditions, the general form of the effective stress paths depending on the overconsolidation ratio is well predicted, as well as pore water pressure. In drained conditions, HASP model predicts the smooth transition from contractive to dilatant behaviour before the peak strength is reached and a smooth transition from hardening to softening, without mathematical description. The yield surface always passes through the current stress point thus enabling elasto- plastic behaviour even in early stages of loading. For normally consolidated clays the HASP model transforms into the Modified Cam Clay model. Validation was done against published results of drained and undrained tests in triaxial compression and extension, on the samples with various overconsolidation ratios. HASP model was implemented in ABAQUS/Standard using the user subroutine UMAT and the Governing Parameter Method for the numerical integration of the constitutive relations. Mean effective stress was adopted for the governing parameter. Possibilities of the HASP model to adequately predict the behavior of overconsolidated clays have been tested through the analysis of a boundary value problem by the finite element method. The problem of the clay settlements due to phased construction of the embankment on the clay surface was analysed, assuming different overconsolidation ratios.

Uloga turističih agencija u plasmanu geoprostora Srbije na turističkom tržištu

The role of travel agencies in the placement of Serbian geospace in the tourism market

Savremeni turizam zahteva razvijen naučni prilaz definisan kroz detaljnu analizu ekonomskih, socio-kulturnih, ekoloških i drugih efekata kao posledica njegovog dinamičnog razvoja po geoprostor u kome se odvijaju turistička kretanja. Turističke agencije kao privredna preduzeća koja predstavljaju posrednika između ponude i tražnje, svojim poslovanjem na turističkom tržištu doprinose stvaranju različitih odnosa koji nastaju kao posledica razvoja turizma unutar određenih geoprostora. Geoprostor Srbije moguće je u formi turističkih aranžmana kao unapred pripremljenih paušalnih ili paket putovanja uspešno plasirati u okvirima domaćeg i međunarodnog turističkog tržišta posredstvom turističkih agencija koje posluju u zemlji. U okviru doktorske disertacije posebna pažnja je usmerena ka identifikaciji uloge turističkih agencija u plasmanu atraktivnih sadržaja geoprostora Srbije na turističkom tržištu i utvrđivanju značaja plasmana geoprostora Srbije posredstvom turističkih agencija na turističkom tržištu, kao dela ukupnih turističkih kretanja i njihov doprinos razvoju turizma na području geoprostora Srbije, kao ciljevima rada; kao i identifikovanju njihove uloge kao faktora unapređenja receptivnog poslovanja u plasmanu atraktivnih sadržaja geoprostora Srbije na turističkom tržištu. Metode istraživanja primenjene u doktorskoj disertaciji čine metod analize prikupljenih podataka, deduktivni metod, metod tehničke analize, sinteza prikupljenih podataka, metod subjektivnih stavova i istorijsko-genetski metod, dok u okviru metoda prikupljenih podataka značajnu ulogu imaju deskriptivni metod koji se zasniva na opisnim objašnjenjima i komparativni metod putem kojeg se upoređuju prikupljeni podaci. U doktorskoj disertaciji su istražene organizaciono- kadrovske i kvalitativne karakteristike poslovanja turističkih agencija u Srbiji, u odnosu na nivo i stanje tehničke opremljenosti i ljudskih resursa, kao i načini poslovanja na turističkom tržištu. Posebna pažnja u radu usmerena je na istraživanje oblika turizma koji dominiraju u ponudi turističkih agencija u Srbiji, kao i uključenosti određenih turističkih motiva i vrednosti u ponudu aranžmana za domaće destinacije, odnosno postojanje razloga zbog kojih turističke agencije ne uključuju domaće destinacije u ponudu turističkih aranžmana. S tim u vezi, definisani su i osnovni predlozi za poboljšanje poslovanja turističkih agencija na turističkom tržištu Srbije, uz identifikaciju rezultata rada i obrazloženje zaključaka, čime se mogu determinisati osnovni pravci budućeg razvoja turizma i shodno tome utvrditi potrebni koraci i osnova za njihove buduće planove.

Modern tourism demands developed scientific approach defined through a detailed analysis of the economic, socio-cultural, environmental and other effects as a result of its dynamic development by geospace where tourism trends occur. Travel agencies, as the commercial enterprises which are intermediaries between supply and demand, contribute, through its operations in the tourism market, to the formation of different relationships that arise as a consequence of the development of tourism within certain geospace. Serbian geospace can exist in the form of holiday packages prepared in advance, as a lump or travel package successfully placed within the domestic and international tourism market by tourist agencies operating in the country. In this dissertation, special attention was directed towards the identification of the role of travel agencies in the placement of Serbian geospace attractive content in the tourism market and the importance of determining the placement of Serbian geospace through travel agencies in the tourism market, as a part of the overall tourism trends and their contribution to the development of tourism in the geospace of Serbia, as working objectives; as well as identifying their role as a factor in improving receptive business in the placement of Serbian geospace attractive content in the tourism market. Research methods applied in this doctoral dissertation consist of a method of analysis of the collected data, deductive method, method of technical analysis, synthesis of the data collected, the method of subjective attitudes and historical and genetic method, while under the method of collected data, descriptive method has a significant role and it is based on descriptive explanations and a comparative method using which the collected data can be compared. This doctoral dissertation examines the organizational, staffing and qualitative characteristics of travel agencies in Serbia, in relation to the level and condition of their technical equipment and human resources, and the ways of doing business in the tourism market. Particular attention is focused on exploring forms of tourism that dominate the supply of travel agencies in Serbia, as well as the inclusion of certain tourist motives and values in the travel package offer for domestic destinations, regarding the existence of the reasons why travel agencies do not include domestic destinations in the offer of travel arrangements. In this regard, basic suggestions for the improvement of travel agencies business in the tourism market of Serbia are defined, with the identification of results and explanation of conclusions, which may determine the main directions of the future development of tourism and consequently determine the necessary steps and the basis for their future plans.

Sleganje površine terena usled izgradnje tunela

Ground surface settlement induced by tunnelling

U gradovima se tuneli najčešće nalaze na maloj dubini ispod gusto naseljenih zona, u tlu ili mekoj steni, i njihova izgradnja može imati veoma nepovoljne efekte na postojeće objekte. Zbog toga je od od izuzetnog značaja da se pri projektovanja tunela adekvatno predvide i kontrolišu sleganja koja su rezultat njegove izgradnje. Metode proračuna sleganja površine terena usled izgradnje tunela mogu se svrstati u tri grupe: empirijske metode, analitička rešenja i numeričke metode. Empirijske i analitičke metode predstavljaju relativno jednostavne i korisne postupke proračuna, međutim mogućnosti njihove primene su ograničene. Empirijske metode, koje se baziraju na pretpostavci da se transverzalni profil sleganja može opisati Gausovom funkcijom normalne raspodele često su korišćene u inženjerskoj praksi. One daju vrlo dobre rezultate kad su uslovi izgradnje tunela dobro poznati, odnosno projektni parametri adekvatno kalibrisani. Analitičke metode daju jednostavna rešenja u zatvorenom obliku, ali je njihova primena u praksi ograničena, jer se zasnivaju na idealizovanim pretpostavkama sa stanovišta geometrije (kružni presek), homogenosti tla, konstitutivnih modela tla i definicije graničnih i početnih uslova. S obzirom da je praktično nemoguće dobiti zatvorena matematička rešenja za izuzetno kompleksne probleme interakcije tunelske konstrukcije i okolne sredine, neophodna je primena savremenih numeričkih metoda. Pri projektovanju tunela, numeričko modeliranje treba da obezbedi da se što realnije reprezentuju procesi koji se odigravaju u tunelskoj konstrukciji i okolnoj sredini, kao složenom interaktivnom sistemu, u toku izgradnje tunela. U skladu sa tim, od izuzetnog je značaja da se sprovede adekvatna proračunska simulacija procesa izgradnje tunela, koji se po pravilu sastoji od sekvenci iskopa i podgrađivanja. Metoda konačnih elemenata je veoma pogodan i široko priznat ii numerički postupak za analize u oblasti geotehničkih radova zbog svoje opštosti i sposobnosti da obuhvati heterogenost sredine, nelinearno ponašanje tla, složenu geometriju problema, interakciju konstrukcije i tla, kao i metod izgradnje. Cilj istraživanja u okviru teze bio je da se, primenom savremenih numeričkih metoda, sagleda interakcija tunelske konstrukcije i tla i da se ispitaju mehanizmi sleganja površine terena. Za adekvatnu analizu naponsko- deformacijskih stanja u tunelskoj konstrukciji i okolnoj sredini od suštinskog značaja je razmatranje delimične relaksacije primarnih napona na radnom čelu tunela, odnosno deformacija površine iskopa koje su se desile pre instaliranja obloge. Da bi se to moglo postići neophodna je trodimenzionalna analiza kojom se simulira napredovanje radova i naponske promene i deformacije u okolini privremenog radnog čela. Međutim, s obzirom da je 3D numeričko modeliranje izgradnje tunela izuzetno zahtevno sa stanovišta kapaciteta i vremena rada računara, primena numeričkih metoda u inženjerskoj praksi je još uvek ograničena na 2D modele. Kada se proces izgradnje tunela razmatra primenom 2D analiza, moraju se na određeni način uključiti 3D efekti izgradnje tunela, odnosno naponsko-deformacijske promene koje se dešavaju na radnom čelu tunela. U tezi je sprovedena parametarska analiza činilaca koji utiču na sleganje površine terena na primeru izgradnje tunela sa otvorenim čelom u beogradskim glinovito-laporovitim sredinama. Analiziran je uticaj dubine tunela, prečnika tunela, dužine napredovanja iskopa, inicijalnih napona u tlu, deformabilnosti i smičuće čvrstoće tla kao i anizotropije tla. Sprovedena je drenirana analiza uz pretpostavku elasto-plastičnog ponašanja materijala sa Mohr-Coulomb-ovim uslovom loma. Profil terena i raspon parametra modela tla usvojeni su na osnovu sprovedene analize geotehničkih karakteristika laporovito-glinovitih sredina u području Beograda. Primenjeno je 3D i 2D modeliranje izgradnje tunela metodom konačnih elemenata. Proračuni su urađeni primenom iii programskog paketa DIANA Finite Element Analysis (TNO DIANA BV). Ovaj program omogućava trodimenzionalnu nelinearnu analizu, kao i modeliranje fazne izgradnje. 3D modeliranje izgradnje tunela je urađeno primenom step-by- step postupka, a 2D modeliranje primenom metode redukcije napona tzv. λ- metode. Izvršena su poređenja poprečnih profila sleganja dobijenih 3D i 2D analizama i ustanovljeno je da, kada se usvoje odgovarajući koeficijenti redukcije napona, 3D i 2D analize daju slične poprečne profile sleganja. Takođe, sprovedeno je poređenje poprečnih profila sleganja dobijenih proračunima sa empirijskom Gausovom krivom. Rezultati istraživanja sprovedenih u tezi obezbeđuju bolje razumevanje problema interakcije tunel-tlo. Pokazano je da je za adekvatnu analizu sleganja površine terena od najvećeg značaja da se na adekvatan način modelira proces izgradnje tunela. Ova istraživanja treba da doprinesu efektivnoj primeni metode konačnih elemenata u analizama tunela. U inženjerskoj praksi, još uvek, uobičajena je primena 2D modela u analizama tunela. U tezi je sprovedena parametarska analiza vrednosti faktora redukcije napona λ, sistematskim poređenjem rezultata 3D i 2D analiza. Rezultati sprovedenih parametarskih analiza vrednosti faktora λ su značajni, s obzirom da se u 2D analizama tunela primenom metode redukcije napona vrednost ovog faktora mora usvojiti. Osim toga, izvršeno je poređenje profila sleganja dobijenih primenom različitih konstitutivnih modela tla (Mohr-Coulomb, Duncan-Chang. Modifikovani Cam clay i Jardine model) i empirijske Gausove krive. Primenom nelinearno elastično plastičnih modela dobijeni su poprečni profili sleganja koji su nešto uži od profila dobijenih primenom linearno elastično plastičnog modela i koji su približniji empirijskoj Gausovoj krivoj. U tezi je sproveden i proračun sleganja za dva konkretna tunela građena u laporovitim sredinama: Steinhaldenfeld NATM tunel (Štutgart, Nemačka) i tunel Dedinje koji se nalazi u sastavu Beogradskog železničkog čvora. Izvršeno je poređenje rezultata proračuna primenom metode konačnih elemenata sa empirijskom Gausovom iv krivom i rezultatima merenja sleganja. Dobijeno je zadovoljavajuće slaganje proračunatih poprečnih profila sleganja sa profilima dobijenim merenjima. Ubrzani urbani razvoj poslednjih decenija doveo je do sve većih zahteva za korišćenjem podzemnog prostora. Širom sveta, u velikim gradovima, grade se i proširuju podzemni transportni sistemi. Od sedamdesetih godina prošlog veka počelo se sa izradom planova za izgradnju metroa i u Beogradu. S obzirom da se očekuje početak izgradnje metroa u skoroj budućnosti, i da će on velikim delom prolaziti kroz prirodne sredine koje su ovde analizirane, tema doktorske disertacije je veoma aktuelna, a rezultati sprovedenih istraživanja mogu imati veliku primenu u praksi.

Tunnels in urban environment are often located at small depth underneath densely populated areas, in the soil or soft rock, and their construction may affect existing structures at the surface. Therefore, prediction and control of ground surface settlements are important tasks when designing an urban tunnel. Methods for the evaluation of ground surface settlements due to tunnelling may be classified into three categories: empirical methods, analytical solutions and numerical methods. Empirical and analytical methods are relatively simple and useful procedures, however, the potentials of their application are limited. Empirical methods, frequently used in engineering practice, are based on the assumption that the transverse settlement profile may be described by Gaussian function. They provide good prediction of surface settlements if tunnelling conditions are known and the design parameters are appropriately calibrated. Analytical methods provide simple solutions in closed form, but their practical application is limited, since they are based on simplifying assumptions in terms of geometry (circular tunnels), homogeneity of the soil, soil constitutive models and the definition of boundary and initial conditions. Since it is practically impossible to get a closed form solutions for extremely complex problems of tunnel - soil interaction, it is necessary to use advanced numerical methods. Numerical modelling should provide a realistic representation of processes that take place in tunnel lining and the ground as a complex interactive system during tunnelling. Accordingly, the process of tunnel construction that consists of excavation and supporting sequences, should be adequately simulated. Finite element method is very convenient and widely recognized procedure for numerical analysis in geotechnical design because of its generality and ability to vi capture the heterogeneity of ground, initial stresses, non-linear behaviour of soil, the complex geometry of the problem, soil-structure interaction, method of construction, excavation stages etc. The objective of this thesis was to analyze the tunnel - soil interaction and to investigate the mechanisms involved in this interaction problem, using advanced numerical methods. An adequate FE analysis of tunnelling should take into account of stress reduction of primary ground stresses at tunnel face, and therefore the initial ground movements prior to lining installation have to be considered. To be able to do this, three-dimensional analysis, which simulates the tunnel advance and stress-strain changes at the temporary working face, is necessary. However, since the 3D numerical modelling of the tunnelling is extremely time consuming, the application of numerical methods in engineering practice is still limited to 2D models. When the construction of a tunnel is simulated using 2D analyses, it is essential to take account of the stress and strain changes ahead of the tunnel face. In this thesis, parametric studies are carried out. Influences of different characteristics on ground surface settlement due to open face tunnelling in Belgrade clayey-marls are analyzed. The effect of depth of the tunnel, the tunnel diameter, the length of excavation, the initial stress in the soil, deformation and shear strength of soil and soil anisotropy are analyzed. Drained ground behaviour was simulated using the elastic-perfectly plastic soil model with Mohr-Coulomb failure criterion. Soil profile and the range of soil model parameters were based on the analysis of geotechnical characteristics of Belgrade marly-clayey sediments. 3D and 2D Finite Element modelling were applied. Computations were performed using the software package DIANA Finite Element Analysis (TNO DIANA BV). This program enables three- dimensional nonlinear analysis and modelling of phased construction. 3D modelling of tunnelling was done by using a step-by-step procedure, while 2D modelling was done by using the stress reduction method, referred to as the λ- vii method. Transverse settlements profiles obtained by 2D and 3D analysis were compared. It is shown that, when appropriate coefficients of stress reduction are adopted, 3D and 2D analysis give similar transverse settlement profiles. Also, computed transverse settlements profiles were compared with Gaussian curve. The results of investigations carried out in this thesis have lead to an improved understanding of the tunnel - soil interaction problem. It is shown that adequately modelling of tunnelling process is of utmost importance. This research should contribute to the effective application of finite element method in tunnel analyses. In engineering practice 2D analyses of tunnelling are often used. Therefore, parametric studies on the magnitude of the stress reduction factor λ were carried out by calibration to results of 3D analyses. These results are important, given that in 2D analysis assumptions have to be made about the magnitude of the factor λ. In addition, transverse settlement profiles obtained by using different constitutive models of soil (Mohr Coulomb, Duncan-Chang, Modified Cam-Clay and Jardine model), were compared to Gaussian curve. It is shown that the application of nonlinear elastic plastic model gives transverse settlement profiles, which are narrower than the profiles obtained by using linear elastic plastic model and are in better accordance with the empirical Gaussian curve. This thesis presents two case studies of tunnels built in marly sediments: Steinhaldenfeld NATM tunnel (Stuttgart, Germany) and tunnel Dedinje, which is a part of the Belgrade railway junction. The transverse settlement profiles computed by using stress reduction method were compared to measured profiles and empirical Gaussian curves and satisfactory accordance was obtained. The rapid urban development in recent decades has led to increasing demands for the use of underground space. Throughout the world, underground transport systems in big cities are being built and expanded. Since the seventies plans to build metro in Belgrade have been made. It is expected that viii construction of the metro will start in the near future, and since it will pass through the soil that was analyzed here, the results of research conducted can have a wide practical application.

Procesnopravni značaj opštepoznatih činjenica i činjenica utvrđenih u pravosnažnim sudskim odlukama

Doktorska disertacija pod nazivom ''Procesnopravni značaj opštepoznatih činjenica i činjenica utvrđenih u pravnosnažnim sudskim odlukama'' prevashodno se bavi činjeničnim pitanjima u krivičnom postupku kako sa aspekta decenijama zastupljenog mešovitog modela postupka, tako i sa aspekta raspravnog ili stranačkog modela, prihvaćenog Zakonikom o krivičnom postupku Republike Srbije iz 2011. godine. Osnovni cilj istraživanja je da pruži određene praktično primenjive odgovore na pitanja iz navedene ''činjenične sfere'' koja su se i do sada pokazivala problematičnim u sudskoj praksi, a koja zahtevaju drugačije rešavanje u skladu sa novousvojenim procesnim modelom. Predmet istraživanja je i detaljna obrada instituta sudske konstatacije odnosno pojma i dejstva opštepoznatih i pravnosnažno utvrđenih činjenica u unutrašnjem, komparativnom i međunarodnom krivičnom pravu. U tom cilju detaljno je analizirana praksa međunarodnih krivičnih tribunala za bivšu Jugoslaviju i Ruandu vezana za pravilo 94 Pravila o postupku i dokazima, koja reguliše formalno primanje na znanje opštepoznatih i pravnosnažno utvrđenih činjenica. Analiza je pokazala da su osnovni problemi kod primene ovog instituta proizilazili iz nerazlikovanja činjeničnog i pravnog, nekonzistentnosti prakse posebno u pogledu česte promene i različitog tumačenja kriterijuma prihvatljivosti, konstatovanja pravnosnažnih činjenica i mimo stranačke saglasnosti, prebacivanja tereta dokazivanja tj. osporavanja na odbranu, čime su dovedeni u pitanje osnovni postulati pravičnog suđenja. Ova pitanja nisu mogla biti analizirana odvojeno od problematike činjenica uopšte i njihovog utvrđivanja u različitim procesnim modelima. Krivični postupak Srbije, oduvek zasnovan na istražnoj maksimi koja je podrazumevala dokazno aktivan sud, poslednjih godina doživeo je korenite reforme prelaskom na stranački model u kome sva dokazna aktivnnost prelazi na stranke. Shodno tome, u radu su analizirane stare procesne dileme, poput razlikovanja činjeničnog i v pravnog, odnosa presude prema optužbi i t. sl, koje zahtevaju drugačije odgovore u kontekstu novousvojenog procesnog modela. Pored toga, detaljno je analizirana i problematika tereta dokazivanja i pretpostavki, dosada nedovoljno razmatrana u našoj krivičnoprocesnoj literaturi. U okviru pravnsnažno utvrđenih činjenica obrađeno je i načelo ne bis in idem, vanredni pravni lekovo i prethodno pitanje. Navedena pitanja su analizirana kako sa aspekta unutrašnjeg prava i domaće sudske prakse, tako i sa komparativno-pravnog, pre svega angloameričkog aspekta, budući da mnoga rešenja sada treba posmatrati u drugačijem kontekstu raspravnog postupka. U velikoj meri je korišćena i praksa Evropskog suda za zaštitu ljudskih prava i osnovnih sloboda, imajući u vidu njegovu kontrolnu ulogu.

Doctoral dissertation about ‘’Generally Known and Adjudicated Facts in Criminal Procedure- Judicial Notice’’, mostly deals with facts and factual issues in criminal procedure, both in terms of mixed and inquisitorial model of procedure, traditionally represented in the countries of continental Europe, and from the perspective of adversarial model, that was introduced in Serbia by the CPC of 2011. Basic purpose of the research was to provide certain, practically implemented answers on these ‘’factual issues’’, that were showed as the most problematic in the practice of the courts, and which require a different answers, in accordance with the newly adopted procedural model. In addition, the subject of research is the institute of judicial notice, related to generally known and adjudicated facts in Serbian, comparative and international criminal law. Regarding this, case-law of the International Criminal Tribunals for former Yugoslavia and Rwanda, related to Rule 94 of the Rules of Procedure and Evidence is matter of detailed analysis. The research showed that the main problems in the application of the Rule 94 emerged from unclear distinction between factual and legal categories, uncertain Tribunal’s jurisprudence that frequently changed and differently interpreted the admissibility requirements, that judicially noticed adjudicated facts without the consent of the parties, what resulted in transfer of the burden of the proof on the defendant, and put under the question the other principles of the fair trial. The issue of judicial notice, adjudicated and generally known facts could not be analyzed separately from the issue of the facts in general and their determination in different procedural models. Serbian criminal procedure traditionally based on the ‘’principle of truth’’ that implies the active judge and passive parties, recently experienced the radical reforms, transferring to the adversarial model where the parties have the ‘’main word’’ in collection and presentation of evidence. Therefore, the old procedural dilemmas like differentiation between facts and law, identity of the indictment and judgment, burden of proof and presumptions, etc, are analyzed through the lens of recently adopted adversarial model, adjusted to Serbian circumstances. In the scope of the vii part that deals with adjudicated or final facts, the matter of particular examination is ne bis in idem rule (or double jeopardy prohibition), extraordinary legal remedies and prejudicial question in criminal procedure. The research is primarily based on case-study method, which sources of data are decisions of Serbian courts, common-law decisions, ICTY and ICTR decisions as well as decisions of European Court of Human Rights. In addition to that, comparative, normative and historical methods of legal research are used as well. The basic purpose of the research is to provide a comprehensive study of the factual issues in criminal procedure, and to serve as some kind of guidance for the courts and legal practice.

Značaj koordinacije monetarne i fiskalne politike za makroekonomsku stabilnost

The importance of coordination between monetary and fiscal policy for macroeconomic stability

Fiskalna i monetarna politika utiču na makroekonomsku stabilnost na brojne načine. Ove politike merama iz svog domena stvaraju eksterne efekte, pa adekvatan okvir analize predstavlja posmatranje njihovog zajedničkog dejstva na makroekonomsku stabilnost, uvažavajući prirodu igre između njih. Polazište istraživanja je stav da makroekonomske politike izolovano ne mogu biti dovoljan garant makroekonomske stabilnosti, niti imaju ekskluzivitet u makroekonomskoj stabilizaciji. Osnovni cilj doktorske disertacije je da se istraže uloga i dometi koordinacije monetarne i fiskalne politike za ostvarenje makroekonomske stabilnosti, tj. da se ustanovi da li nekoordinisane politike dovode do inferiornih ishoda. Pored toga, cilj disertacije je inkorporacija uticaja interakcija kreatora ekonomske politike u standardni makroekonomski okvir prilikom teorijskog i empirijskog modeliranja. U istraživanju su korišćene brojne kvalitativne metode. One su imale za cilj upoznavanje sa obimnom literaturom iz ove i srodnih oblasti, predstavljanje razvoja koncepta koordinacije monetarne i fiskalne politike u makroekonomskoj teoriji i politici, utvrđivanje ciljeva koordinacije, prikazivanje dosadašnjih ostvarenih rezultata u istraživanjima ovog problema, prezentovanje dometa i ograničenja teorije ekonomske politike, grupisanje teorijskih modela u zavisnosti od tipa strategijske interakcije među kreatorima ekonomske politike, sagledavanje prednosti i nedostataka različitih teorijskih modela, klasifikaciju mehanizama koordinacije i poređenje njihove delotvornosti, komparaciju efekata interakcija kreatora ekonomske politike pri dejstvu šokova, komparaciju zaključaka empirijske analize i donošenje kako opštih tako i pojedinačnih zaključaka relevantnih za predmet istraživanja. U istraživanju su korišćene i brojne kvantitativne metode makroekonomskog i ekonometrijskog modeliranja. Najpre je problem koordinacije monetarne i fiskalne politike prikazan u okvirima makroekonomskih modela koji pripadaju klasi dinamičko stohastičkih modela opšte ravnoteže. Primenjene su brojne varijacije ovog modela kroz uvođenje mogućnosti promene režima, nelinearnih ograničenja i interakcija kreatora monetarne i fiskalne politike.

Fiscal and monetary policy influence macroeconomic stability on various ways. These economic policies create external effects by conducting measures in their respective areas, which implies that the adequate framework for the analysis assumes observation of their joint effect on the macroeconomic stability, respecting for the nature of the game between them. The initial point is that macroeconomic policies neither can separately be a guarantee of macroeconomic stability, nor have they exclusivity in the process of macroeconomic stabilization. The main goal of the dissertation is to research the role and the scope of coordination between monetary and fiscal policy for the macroeconomic stability, i.e. to investigate do uncoordinated policies cause inferior outcomes. In addition, the aim of the dissertation is incorporation of the influence of policymakers’ interactions into the standard macroeconomic framework during theoretical and empirical modeling. Numerous qualitative methods are used in the research. They have the goal to introduce the research and show its place in the literature in that area, present the development of concept of coordination between monetary and fiscal policy, define the goals of coordination, review the previous achieved results, present scope and limits of theory of economic policy, cluster theoretical models depending on strategic interactions type, investigate the advantages and disadvantages of various theoretical models, classify mechanisms of coordination and examine their effectiveness, compare the effects of interactions between policymakers after the shocks, compare the conclusions of empirical analysis and make the general and specific conclusions relevant for research subject. Various quantitative methods of the research are used for macroeconomic and econometric modeling. Initially, the problem of coordination between monetary and fiscal policy is presented in the framework of macroeconomic models which belong to the class of dynamic stochastic general equilibrium models. Numerous variations of these models are applied, which include the possibility of regime switching, nonlinear constraints and interactions between fiscal and monetary policymakers.

Geostatistical modeling of geochemical variables in 3D

Geostatistiˇcko kartiranje zemljišta u 3D odnosi se na primenu geostatistiˇckih metoda na zemljišnim podacima u cilju izrade karata zemljišnih karakteristika jednog podruˇcja, koje se odnose na razliˇcite dubine zemljišta. U okviru dve nezavisne studije, ova doktorska disertacija razmatra dva razliˇcita pristupa geostatistiˇckog modeliranja zemljišta u 3D. U okviru prve studije, "Spline-Than-Krige" metod je koriš´cen za kartiranje koncentracije arsena u zemljištu, u blizini Rudarsko-topioniˇcarskog basena Bor, na tri razliˇcite dubine (0-5 cm, 5-15 cm i 15-30 cm). Dugogodišnje emitovanje nepreˇciš´cenih materija iz topionice rudnika u atmosferu, dovelo je do zagadjenja zemljišta u okolini, taloženjem štetnih materija nošenih vetrom. U odsustvu podataka kojima bi se detaljnije mogao opisati proces raspršivanja štetnih materija, ova studija se ograniˇcila na analizu izloženosti terena uticaju vetra, a time i procesu zagad¯enja. Predstavljen je inovativan pristup kvantifikaciji izloženosti terena izvoru zagad¯enja. Na osnovu opšte dostupnih podataka, kreirano je nekoliko parametara kojima se kvantifikuje geometrijska i topografska izloženost svake tacˇke terena izvoru zagad¯enja. Tako kreirani parametri, iskorišc´eni su za opisivanje prostornog trenda koncentracije arsena na tri razliˇcite dubine. Definisani trendovi, koriš´ceni su u okviru regresionog kriginga, za prostornu predikciju. Na taj naˇcin pokušalo se odgovoriti na pitanje, u kojoj meri, opšte dostupni podaci, kao što su pravac dominantnog vetra ili poznavanje taˇcne lokacije izvora zagadjenja u kombinaciji sa digitalnim modelom terena, mogu biti iskoriš´ceni da bi se unapredila preciznost prostorne predikcije zemljišnih zagadjivaˇca, kako na površinskim slojevima tako i na ve´cim dubinama...

Geostatistical mapping of soil properties in 3D refers to the application of geostatistical methods to the soil data in order to produce maps of soil properties at different depths. Through two separate studies, this thesis elaborates on two different approaches for 3D soil mapping. At first, the well established Spline-Than-Krige approach for the mapping of soil pollutants atmospherically deposited from the copper smelting plant, was used. In the absence of the monitoring data, which can be used for a detailed characterization of the plume spreading process, this study was confined to the consideration of terrain exposure to explain spatial trend in arsenic distribution at different depths. This study aims to explore the extent to which the commonly available information, such as the prevailing wind direction, or the location of the source of pollution, in combination with the digital terrain model, can be used to quantify the terrain exposure, and hence to improve the spatial prediction of the arsenic concentration at several soil depths. Next, the innovative geostatistical approach to 3D mapping of soil properties, based on soil profile data, was proposed. It provides the semi-automatic way for 3D modeling of soil variables, prediction over the regular grids (rasters) and also the evaluation of prediction accuracy. Methodologically, this approach operates within the 3D regression kriging framework. 3D trend model is conceptualized as hierarchical or non-hierarchical linear interaction model. This means that the model includes the interactions between the spatial covariates and depth in the hiearchial or non-hierarchial manner. The trend modeling is based on the application of the penalized regression technique, lasso. The lasso uses a specific regularization penalty in a fitting procedure to enable the efficient parameter estimation and variable selection (including interaction terms) at the same time...

Burno tečenje u krivinama evakuacionih objekata

Supercritical flow in spillway conduit bends

U okviru doktorske disertacije je analizirano tečenje u provo- dniku kružnog poprečnog preseka koje nastaje usled prisustva horizontalne krivine pri burnom toku. Na fizičkom modelu je ispitan uticaj geometrijskih karakteristika krivine (zakriv- ljenost i skretni ugao) i uslova tečenja u uzvodnoj neporemećenoj zoni (relativna dubina i Frudov broj) na nastanak helikoidnog tečenja i zagušenja toka. Na osnovu analize rezultata modelskih ispitivanja, izvedene su empirijske jednačine kojima se u zavi- snosti od pomenutih veličina datim u bezdimenzionalnom obli- ku, opisuju zone nastanka određenog tipa tečenja. Provera pred- loženih empirijskih izraza za širi spektar uslova tečenja i karakteristika krivine je urađena primenom numeričkog mode- la, formiranog u okviru programskog paketa Fluent. Na njemu su analizirani slučajevi koji zbog ograničenosti kapaciteta labo- ratorijske instalacije nisu mogli da se ispitaju na fizičkom modelu. Rezultati ispitivanja na fizičkom modelu su korišće- ni i za određivanje gubitka energije koji nastaje u provodniku pri helikoidnom tečenju. Definisani su opšti izrazi kojima se u zavisnosti od karakteristika krivine određuje ovaj koefici- jent gubitka.

A complex flow pattern occurring in a circular conduit bend with supercritical flow has been studied. The influence of geometry (bend curvature and deflection angle) and approach flow conditions (relative flow depth and Froude number) on the inception of helical and choking flow are analyzed on the scale model. A series of experiments provided data for developing empirical relationships describing the effects of aforementioned variables given in nondimenzional form on the inception of a certain type of flow. Empirical relationships are checked by the numerical model for a wider range of approach flow conditions and bend curvatures. Numerical model is prepared using software package Fluent, and it was used to simulate conditions that could not be examined on scale model due to the limited capacity of the laboratory installation. Based on the scale model experiments, the energy loss for helical flow are also determined. Empirical relationships for the energy bend loss coefficient depending on the bend curvature and deflection angle were proposed.

Primena savremenih klasifikacija klimata na klimatsku regionalizaciju Srbije

Аpplication of recent climate classifications for the climate regionalization of Serbia

Poznato je da u različitim delovima Zemlje deluju različiti klimatski elementi i faktori i njihova međusobna prostorno-vremenska interakcija sa vegetacijom i ostalim komponentama klimatskog sistema ima za posledicu formiranje različitih tipova klimata u različitim geografskim prostorima. Cilj doktorske disertacije ima više aspekata. S obzirom na činjenicu da u domaćoj literaturi ima tek nekoliko radova koji se bave problematikom „objektivne“ regionalizacije i klasifikacije klimata, cilj disertacije je upravo da se izvrši klimatska regionalizacija Srbije upotrebom savremenih matematičko-statističkih i geostatističkih metoda, kao i klimatska klasifikacija pomoću različitih klimatskih indeksa. Cilj disertacije je i ispitivanje veze između korišćenih klimatskih indeksa sa prostornom dimenzijom temperature vazduha i padavina. Takođe, jedan od ciljeva je i da se izvrši komparativna analiza sa postojećim regionalizacijama i klasifikacijama koje su do sada urađene za prostor Srbije. Kako bi se utvrdilo da li je na prostoru Srbije u 60-godišnjem periodu osmatranja došlo do klimatskih promena, trebalo bi uporediti klimatsku regionalizaciju Srbije za dva nestandardna klimatološka perioda: 1951-1980. i 1981-2010. Saglasno stepenu složenosti i obimu predmeta proučvanja doktorske disertacije, a u cilju realizacije istraživanja u okviru zadate teme, upotrebljeni su provereni naučni metodi koji su u skladu sa postavljenim ciljevima, zadacima i strukturom rada. Analizirane su srednje mesečne, tj. srednje godišnje vrednosti dve glavne prizemne sinoptičke varijable, tj. dva glavna klimatska elementa-temperature vazduha i padavina za period od 60 godina (1951-2010), a na osnovu podataka sa 31 meteorološke stanice uključene u analizu. Razmatrane su karakteristike 13 klimatskih klasifikacionih šema i izvršena je komparacija i statistička evaluacija između sličnih klasifikacionih šema primenom modela linearne regresije najmanjih kvadrata. Primenjena je savremena multivarijaciona tehnika klaster analize (hijerarhijska i nehijerarhijska metoda) u cilju „objektivne“ regionalizacije klimata u Srbiji. Analiza vremenskih serija temperature i padavina urađena je na sezonskom i godišnjem nivou, a od primenjenih metoda mogu se izdvojiti sledeće: metod linearnog trenda, metod kliznih srednjaka, Man-Kendalov trend test i Senova ocena nagiba trenda, spektralna analiza proste periodičnosti, kao i geostatistički interpolacijski metod inverznih rastojanja...

It is well known that various parts of Earth are under the influence of different climate elements and factors and that their spatial-temporal interaction with the vegetation and other components of the climate system causes the formation of various climate types in different geographic areas. The aim of the doctoral dissertation includes several aspects. Considering the fact that there are just a few studies in the national literature dealing with an “objective” climate regionalization and classification, the aim of the dissertation is in fact to make both climate regionalization of Serbia, by using recent mathematical-statistical and geostatistical methods, and climate classification based on different climate indices. The aim also includes an investigation into the relationship between climate indices used in the study and spatial dimension of air temperature and precipitation. Also, one of the main objectives is to make a comparative analysis with existing regionalization and classifications made so far for the area of Serbia. In order to determine whether there were climate changes in the 60-year observation period on the territory of Serbia, climate regionalization of Serbia should be compared, taking into account two non-standard climate periods: 1951-1980 and 1981-2010. Considering the complexity and the scope of the subject matter in the dissertation and for the purpose of research realization within the topic, approved scientific methods corresponding with the aims, tasks and structure of the study are used. Mean monthly, that is, mean annual values of two major surface synoptic variables, in other words, two main climate elements-air temperatures and precipitation for a 60-year period (1951-2010) have been analyzed according to the data taken from 31 weather stations included in the analysis. 13 features of climate classification patterns have been studied and a comparative analysis and statistical evaluation between similar classification patterns have been made by using Linear Least Squares Regression models. An up-to-date multivariate technique of cluster analysis (hierarchical and non-hierarchical methods) has been applied for the purpose of an “objective” climate regionalization of Serbia. An analysis of temperature and precipitation time series has been done on a seasonal and annual level by using following methods: linear trend method, moving average method, Mann-Kendall trend test and Sen’s slope estimator, spectral analysis of simple periodicity, and geostatistical interpolation method of inverse distances...

Vulnerability of reinforced concrete bridges to local scour in bridge management

Upravljanje armiranobetonskim mostovima u kontekstu njihove ugroženosti lokalnom erozijom rečnog dna.

Putna infrastruktura širom sveta je ugrožena prirodnim nepogodama, posebno sa ektremnim poplavama, koje dovode do prekida putnih pravaca a samim tim i do ozbiljnih socio-ekonomskih posledica. Mostovi kao najkritičniji segmenti putnih pravaca su ugroženi čak i sa ne tako ekstreminm poplavama koje imaju veliku učestalost događanja. Lokalna erozija rečnog dna kod donjeg stroja mostova koja se događa u poplavama je najveći uzrok otkaza i oštećenja mostova izazvanih prirodnim nepogodama. Iako tema upravljanja mostovima koji su izloženi poplavama nije nova i značajno je obrađivana u predhodnih 20 godina, današnji Sistemi Upravljanja Mostovima i dalje ne uzimaju u obzir iznenadne ekstremne događaje kao što je lokalna erozija rečnog dna. Ovaj problem se u današnjoj praksi uglavnom tretira kvalitativnim pristupom koji se oslanja na bazu podataka mostova i regularne inspekcije, međutim to ne daje zadovoljavajuće rezultate i ocena promene rizika od eksteremnih poplava u realnom vremenu se smatra neophodnim. Tema ove teze je predstavljanje osnove za novu metodologiju za kvantitativnu ocenu ugroženosti armiranobetonskih mostova sa plitko fundiranim temeljima izloženih lokalnoj eroziji rečnog dna. Akcenat je stavljen na određivanje uslovne verovatnoće loma mosta usled lokalne erozije rečnog dna dok posledice ovakvog događaja nisu razmatrane u okvirima teze. Bazirajući se na mostovima koji su ugroženi erozijom rečnog dna u putnoj mreži Srbije, razmatrani su kontinualni gredni armiranobetonski mostovi sa glavnim nosačem koji ima poprečni presek duplog slova T. Prilikom rešavanja multidisciplinarnog problema otkaza mosta usled lokalne erozije rečnog dna kod stubova, bilo je neophodno definisati tipični model tlo-most i postupak sa ograničenim brojem ulaznih podataka potrebnih za njegovu uprošćenu ali dovoljno preciznu analizu. Ovde je kao opšti pristup za analizu mogućih mehanizama loma modela i određivanje uslovne verovatnoće loma razmatrana interakcija voda-tlo-most i pretpostavljeno je kruto-plastično vi ponašanje elemenata modela kako bi se primenila gornja teorema teorije plastičnosti. Prvi korak u analizi je pojednostavljenje načina delovanja lokalne erozije rečnog dna oko mostovskih stubova i ovde je razmatrana mogućost primene formula za evaluaciju lokalne rečne erozije u oceni ugroženosti mostova, oslanjajući se na savremena istraživanja. Prednost je data onim formulama koje mogu uzeti u obzir rast dubine erozije u toku vremena. Geometrija erodiranog tla oko i ispod mostovskih stubova je uprošćena tako da se način delovanja lokalne erozije na kostrukciju može posmatrati kroz ravanski problem. Drugi korak u analizi je proračun otpornosti oslonačkog tla i mostovske konstrukcije na usvojenu uprošćenu geometriju potkopavanja kod stubova. Ovde je smanjenje granične nosivosti tla modelirano uz pomoć osnovnih kinematičkih mehanizama koji se zasnivaju na geotehničkim svojstvima tla i uzimaju u obzir geometriju potkopavanja. Otpornost mostovske konstrukcije je uzeta u obzir preko plastične nosivosti njenih elemenata, određene na osnovu karakteristika konstruktivnog sistema mosta i detalja armiranja. Za definisan model tlo-most, posebno za podužni i poprečni pravac mosta, određuju se kombinovani mehanizmi otkaza tako što se dovode u vezu usvojeni kinematički mehanizmi za tlo i mehanizmi loma gornjeg stroja mosta. Kombinovani mehanizmi se potom koriste u optimizacionoj proceduri gde je maksimalna otpornost modela tlo-most određena kao najveći horizontalni domet potkopavanja lokalne erozije rečnog dna kod mostovskog stuba. Neizvesnosti kod određivanja parametara potrebnih kod evaluacije lokalne rečne erozije, karakteristika tla i nosivosti elemenata mostovske konstrukcije su razmatrane na bazi savremenih istraživanja kao glavna tema pri proračunu uslovne verovatnoće otkaza mosta. Na primeru kontinualnog mosta na četiri polja koji prelazi preko reke, sračunate su uslovne verovatnoće loma mosta u Monte Karlo simulacijama za četiri scenarija. Ovde je u graničnoj funkciji uzeta u obzir vremenski zavisna dubina lokalne erozije i otpornost modela tlo-most na širenje zone potkopavanja kod mostovskog stuba. vii Predstavljeni model tlo-most razjašnjava ponašanje plitko fundiranih kontinualnih grednih armiranobetonskih mostova izloženih delovanju lokalne erozije rečnog dna i daje gornju granicu prostiranja erozije kod mostovskih stubova koja dovodi do otkaza konstrukcije. Kao esencijalna komponenta za analizu ugroženosti, razmatrana je kombinovana otpornost oslonačkog tla i mostovske konstrukcije na lokalnu eroziju rečnog dna, što nije bilo tema predhodnih naučnih istraživanja. Predstavljena metodologija za kvantitativnu ocenu ugroženosti predstavlja osnovu za razvoj mapa ugroženosti putnih mreža u ekstremnim poplavama. Ove mape će posebno biti korisne kod upravljanja resursima za ublažavanje rizika od poplava kao i za izdavanja ranih upozorenja na opasnost u područijima gde se očekuju poplave velikog intenziteta.

The road infrastructure around the world is impaired by natural hazards, in particular with extreme flooding, which sever the road links and lead to serious socio-economic consequences. The bridges, which are the most critical parts of road links, are threatened even by less extreme floods with high occurrence rates. The local scour at bridge substructures associated with floods is regarded as the predominant cause of hazard triggered failures. Although the management of bridges exposed to flooding is not a new topic and has been extensively elaborated in the last 20 years, the current Bridge Management Systems still cannot account for sudden events such as the local scour. The current procedures, which usually rest on qualitative approaches and regular inspections, do not give satisfactory results in scheduling the appropriate risk reducing interventions. The evaluation of real-time risk changes associated to this hazard is deemed necessary. The topic of the thesis is to present the basis of the novel methodology for quantitative vulnerability assessment of reinforced concrete bridges with shallow foundations exposed to local scour. Here, the accent is set on the estimation of the conditional probability of a bridge failure due to a scouring event, while the related consequences are beyond the scope of the thesis. Based on the scour critical bridges in the Serbian road network, the reinforced concrete bridge types which are considered in the analysis have multiple span double-tee main girders on common pier-foundation systems. In order to solve the multidisciplinary problem of local scour action at bridge piers and associated failures, it was essential to develop a typical bridge model and framework with a modest data set for its simple yet accurate analysis. As the general approach to analyze possible failure modes and consequently obtain the probability of bridge failure, the water-soil-bridge interaction is suggested. In addition, the perfectly rigid plastic behavior of soil and bridge is assumed to apply the upper bound theorem of the theory of plasticity. iii The first step in the analysis is the approximation of the local scour action and here the choice of the appropriate local scour formula is discussed based on the state-of-the-art research on pier scour, giving the advantage to the formulas that may consider temporal aspect. The scour cavities beneath the common pier-foundation systems are given by the time-dependant local scour depth and their geometry is approximated in order to simplify the local scour action to a plane strain problem. The second step in the analysis is evaluation of supporting soil and bridge resistances to the approximated scour cavities. The cavities` influence on the decrease of a bearing capacity of the supporting soil at an affected pier is considered with basic kinematic mechanisms which are based on soil properties. The bridge resistance is given by plastic strengths of its elements, which is based on structural system properties and reinforcement detailing. The soil-bridge model is defined, and separately for its longitudinal and lateral direction, the adopted kinematic mechanisms in the supporting soil are coupled with the possible failure modes of the bridge superstructure to reveal combined failure modes. These are consequently used in the optimization procedure, where the resistance of the model to local scour action is obtained as the ultimate horizontal scour extent beneath a shallow foundation. The uncertainties related to parameters used in the local scour evaluation, soil properties and bridge elements’ properties are discussed as the essential topic in calculation of the conditional probability of a bridge failure relying on the state-of-the- art research. In the example of a four span continuous bridge over a river channel, the conditional probabilities of the bridge failure are estimated in Monte Carlo simulations for four scenarios. Here, the limit state function accounts time-dependant local scour depths and the resistance of the assumed soil-bridge model to local scour action at the affected bridge pier. The presented soil-bridge model clarifies the behavior of multiple span reinforced concrete girder bridges with shallow foundations in a scouring event. It sets the upper bound of the local scour extent at bridge piers necessary to trigger a failure. Here, in the calculation of the conditional probability of a bridge failure due to local scour, the combined resistance of the supporting soil and the bridge structure to local scour action is included as the essential ingredient, which has not been done in the iv up-to-date research. The suggested methodology for quantitative vulnerability assessment provides a basis for development of vulnerability maps for road networks in respect to extreme flooding. These maps are going to be especially useful for unambiguous allocation of resources for mitigating the threat from future flooding events and issuing timely warnings in the regions where intensive flooding is expected.

Romantizam u srpskoj književnosti iz imagološke perspektive

Romantizam u srpskoj književnosti iz imagološke perspektive

Autorka je u radu sistematizovala i predstavila slike, predstave i stereotipe koje su kanonizovani pesnici srpskog romantizma u svojim delima konstruisali o Srbima i Drugima, problematizovala je i istražila vezu i uticaj kanona na kreiranje slika i predstava i njihovu meĎusobnu uslovljenost.

In this work, the author systematized and presented the images, notions and stereotypes that the canonized poets of Serbian romanticism have constructed in their works about Serbs and Others, questioning and researching the relationship and the influence of canons on creation of images and notions and their mutual conditionality.

Potpuni metod najmanjih kvadrata u funkciji rešavanja geodetskih problema

Total Least Sqares Method for Solving Geodetic Tasks.

Doktorska teza je posvećena primeni tehnike potpunog metoda najmanjih kvadrata (Total Least Squares, TLS) u oceni parametara matematičkih modela različitih geodetskih problema. Potpuni metod najmanjih kvadrata je relativno nova tehnika ocenjivanja parametara modela. Prva istraživanja na polju matematike datiraju od ranih osamdesetih godina prošlog veka a prve primene javljaju se u različitim negeodetskim disciplinama. Istraživanja mogućnosti primene u oceni parametara geodetskih modela kasnijeg su datuma i javljaju se pre oko deset godina (Kupferer, 2005, Schaffrin, 2006). Istraživanja se razvijaju u pravcu prilagođavanja TLS geodetskim problemima u smislu nalaženja rešenja koje uračunava različitu tačnost kao i međusobnu korelisanost podataka (rezultata merenja). Da bi se to postiglo, umesto rešenja dobijenih primenom dekompozicije proširene matrice modela na singularne vrednosti razvijena su rešenja na osnovu minimizacije Lagrange- ove funkcije cilja (Euler- Lagrange-ov postupak). U okviru doktorske teze prikazani su klasični (tradicionalno primenjivani) modeli u rešavanju geodetskih zadataka, posebno Gauss-Helmert-ov model kojime se takođe mogu rešavati problemi tretirani primenom TLS. Takođe, istraženi su i prikazani različiti oblici TLS modela kako klasični (homoskedastički) tako i težinski odnosno modeli koji uračunavaju različite varijanse kao i međusobnu korelaciju članova proširene matrice modela. Pored toga, date su formule za ocenu tačnosti odnosno računanje kofaktorskih matrica ocena parametara modela kao i korekcija (popravaka, reziduala) rezultata merenja i članova matrice modela. Na tri karakteristična geodetska problema ilistrovana je primena TLS u rešavanju geodetskih zadataka.

A doctoral thesis deals with the application of Total Least Squares (TLS) techniques for parameters estimation of mathematical models for various geodetic problems. Total Least Squares is a relatively new technique of parameters model estimation. The first research in the field of mathematics dating from the early eighties and the first applications appeared in various nongeodetic disciplines. Studies on possibility of applications in the parameters estimation of geodetic models are of later date, there are about ten years ago (Kupferer, 2005 Schaffrin, 2006). Research is developing towards adjustment TLS geodetic problems in the sense finding a solution that include different accuracy and mutual correlation of data (measurement results). In order to achieve this, rather than solutions obtained by decomposition of the extended matrix model on the singular values (SVD), solutions based on the minimization of Lagrange's objective function (Euler-Lagrange's method) are developed. In the scope of the doctoral thesis, classical (traditional applied) geodetic models are presented, especially Gauss-Helmert's model by which the problems treated by TLS tchniques can also be solved. Also, various forms TLS models are explored and presented, from classic (homoskedastic) TLS models to weighted TLS models or models that include different variances as well as mutual correlation between members of the extended matrix model. In addition, the formulas for the accuracy assessment and cofactor matrices computation for parameters model estimate, correctinons of the measurement results and correctinons of the matrix model members are developed. The applicatins of TLS for sovnig geodetic tasks are illustrated on the three characteristic cases.

Ojačanje drvenih nosača u zoni redukcije visine preseka

Strengthening of notched timber beams

Potreba za redukcijom visine drvenih nosača najčešće se javlja kod oslonaca, kada arhitektonski uslovi oblikovanja konstrukcije zahtevaju smanjenu visinu na ovom mestu. Kao posledica redukcije visine, a usled složenog naponskog stanja (zatezanje upravno na vlakna i smicanje), na zasečenim delovima nosača formiraju se horizontalne pukotine. Propagacija pukotine može dovesti do loma nosača. Razmatrajući probleme koji se javljaju sa redukcijom visine drvenih nosača, ovaj rad ima za cilj da utvrdi mogućnosti primene ojačanja i predloži metode proračuna nosača sa redukovanom visinom preseka kod oslonaca. Akcenat je stavljen na primenu savremenih materijala kao što su GFRP (Glass Fibre Reinforced Polymer) šipke za ojačanje. U okviru ovog rada izvršena su eksperimentalna ispitivanja na savijanje do loma neojačanih i ojačanih nosača od lepljenog lameliranog drveta sa redukovanom visinom preseka kod oslonaca. Kao ojačanje su korišćeni zavrtnjevi i GFRP šipke. Ponašanje nosača je opisano kroz dijagrame sila - ugib, raspodelu napona i deformacija, oblike loma i vrednosti granične nosivosti. Pored navedenog, analizirane su različite konfiguracije ojačanja na mestu redukcije visine preseka kako bi se došlo do optimalnog rasporeda s aspekta maksimalnog poboljšanja nosivosti u odnosu na neojačane nosače. Dobijeni rezultati eksperimentalnih ispitivanja neojačanih i ojačanih zasečenih nosača su poslužili kao osnova za definisanje analitičkih metoda proračuna i numeričkih modela na bazi metode konačnih elemenata razvijenih u Abaqus-u. Na osnovu teorijskih razmatranja i eksperimentalnih ispitivanja utvrđeno je da GFRP šipke predstavljaju efikasno sredstvo ojačanja drvenih nosača sa redukovanom visinom preseka kod oslonaca. Adekvatno postavljanje ojačanja može obezbediti punu nosivost nosača na savijanje, kao da nema slabljenja preseka.

Notches in timber beams are usually made at the supports, as a consequence of architectural design requirements that ask for a reduction in height at these positions. As a result of height reduction, and due to a complex stress state (tensile stress perpendicular to grain and shear stress), horizontal cracks are formed at the notches. Crack propagation can lead to beam failure in the notch area. Considering the problems that occur in notched beams, this thesis aims to determine the possibilities of reinforcement techniques and to propose design methods of end-notched beams. The emphasis is placed on the application of modern materials such as GFRP (Glass Fibre Reinforced Polymer) rods as a reinforcement. In this thesis, bending tests on unreinforced and reinforced end-notched glulam beams were carried out until the point of failure. Screws and GFRP rods were used as reinforcement. Behaviour of tested beams is described through load-deflection diagrams, distribution of stresses and deformations, failure modes and ultimate loads. In addition, different reinforcement schemes of notches have been analysed in order to determine an optimal configuration from the aspect of ultimate load improvement in relation to the unreinforced beams. The obtained results of experimental investigations on unreinforced and reinforced end-notched beams served as a basis for defining analytical design methods and numerical models based on the finite element method developed in Abaqus. Based on theoretical and experimental analysis it was determined that GFRP rods represent an effective method of end-notched beams reinforcement. Adequate reinforcement technique can restore the full load carrying capacity of end-notched beams, as if there were no notches at the supports.

Prognostički značaj komorbiditeta u bolesnika sa lokoregionalno uznapredovalim, inoperabilnim planocelularnim karcinomima glave i vrata

The prognostic significance of comorbidity in patients with locoregionally advanced, inoperable squamocellular head and neck cancers

U savremenom dobu personalizovane medicine, faktori prognoze vezani za pacijenta potvrdili su svoj značaj u smislu boljeg terapijskog planiranja i preciznije procene preživljavanja. U bolesnika sa malignim bolestima često se javljaju druga oboljenja ili stanja,nevezana za sam tumor koja se zajednički nazivaju komorbiditetom. Zahvaljujući činjenici da poznati rizikofaktori za nastanak planocelularnih karcinoma glave i vrata kao što su zloupotreba duvana i alkohola mogu dovesti do oštećenja drugih važnih organa, bolesnici sa ovom vrstom tumora pogodni su za analizu uticaja komorbidnih stanja na prognozu maligne bolesti. Cilj rada je procena prevalence komorbiditeta i najčešćih komorbidnih stanja kao i njihovog uticaja na prognozu preživljavanja u ovoj populaciji bolesnika. Materijal i metode U periodu od jula 2002.g do januara 2007.g 100 bolesnika sa lokoregionalno uznapredovalim,inoperabilnim, planocelularnim karcinomima glave i vrata lečeno je na Institutu za Onkologiju i Radiologiju Srbije neoadjuvantnom hemioterapijom u sastavu Citarabin-5 fluorouracil-Cispaltina. Medijana starosne dobi obolelih bila je 55 godina,najvećim delom muškarci (91%), sa prosečnim brojem primenjenih hemioterapijskih ciklusa od 4. Podaci o komorbidnim stanjima prikupljani su prospektivno korišćenjem različitih izvora podataka i to pre početka samog lečenja. Za procenu ozbiljnosti komorbidnih stanja korišćen je ACE-27 komorbidni indeks sa četvorostepenom skalom (0-3). Prosečno vreme praćenja bolesnika iznosilo je 15 meseci sa rasponom od 3 do 59 meseci. Rezultati Komorbiditet je bio prisutan u 69 bolesnika (69%) dok 31 bolesnik (31%) nije imao komorbidnih stanja pre početka lečenja. Najčešća komorbidna stanja odnosila su se na alkoholizam, aktivni ili raniji (71%),zatim hronične plućne bolesti (25%) kao i kardiovaskularne bolesti (18%). Ukupni komorbidni zbir odredjen je na osnovu najviše rangiranog opserviranog komorbidnog stanja,osim u slučaju gde su opservirana dva ili višeoboljenja gradusa 2, u različitim organima u kom slučaju je ukupni komorbidni zbir iznosio 3. Prosečno preživljavanje za celu grupu bolesnika iznosilo je 12 meseci. Srednji ACE-27 skor iznosio je 1 sa rasponom od 0 do 3 i bio je prisutan u 43 bolesnika (43%). Bolesnici bez komorbiditeta imali su značajno duže preživljavanje u odnosu na one sa bilo kojom vrstom komorbiditeta ( p= 0,0089), a isto je zapaženo poredjenjem preživljavanja u bolesnika bez komorbiditeta u odnosu na bolesnike sa komorbiditetima gradusa 2 i 3 uzeto zbirno (p= 0,0047). Rezultati ostalih poredjenja izmedju grupa nisu bili statistički značajni. Zaključak Komorbiditet je važan prognostički parametar u bolesnika sa lokoregionalno uznapredovalim planocelularnim karcinomima glave i vrata pa se savetuje odgovarajuća procena pre početka lečenja.

In present era of personalized medicine prognostic factors related to patients regained its importance in respecct to bettter treatment planning and more accurate prediction of survival.Patients with tumours often have other diseases or conditions in addition to their index cancer which are generally referred to as comorbidities.Due to the fact that well known risk factors for development of HNSCC such as tobacco and alcohol abuse can also damage other important organs,patients with this type of cancer are suitable for analysing the influence of comorbid conditions on prognosis of the disease. Aim of our work is to assess the prevalence of comorbidities,most frequent conditions and prognostic impact on overall survival in this particular population. Matherial and methods Between July 2002 and January 2007 in Institute for oncology and radiology of Serbia, 100 patients with locoregionally advanced inoperable HNSCC were initially treated with neoadjuvant chemotherapy regimen Cytarabine-5 Fluorouracil-Cisplatinum. Median age of patients was 55 years,most of them males (91%) with median number of applied chemo cycles being 4. Data on comorbidity were collected in prospective manner from various sources prior to treatment. For grading of the severity of comorbid conditions, ACE-27 comorbidity index was used with four degree scale (O-3) . The average follow-up of patients was 15 months with range from 3-59 months. Results Comorbidity was present in 69 pts (69%),and 31 pts (31%) had no comorbidities prior to treatment. Among pts with comorbid conditions prevail alcoholics,active and former (71%),pts with chronic lung diseases (25%) and cardiovascular diseases(18%). Overall comorbidity score is defined according to the highest ranked single ailment,except in the case where two or more grade 2 ailments occur in different organ systems in which case the overall comorbidity score is designated as grade 3. Median overall survival for the whole group was 12 months. Median ACE- 27 score was grade 1 ( range 0-3) which was observed in 43 pts (43%). Pts without comorbidities survive significantly longer than those with any kind of comorbidity ( p=0,0089 ), and the same was observed comparing survival of pts without comorbidities and those with grade 2 and 3 taken together ( p= 0,0047). Results of other intergroup comparisons were of no statistic significance. Conclusion Comorbidity is important prognostic variable in patients with locoregionally advanced HNSCC and should be properly assessed prior to therapy.

Damage detection and localization for civil structural health monitoring

Detekcija i lokalizacija oštećenja pri monitoringu stanja građevinskih konstrukcija

Prikazani teza studije je predložio nove procedure koje se sprovode da razvije Strukturno Zdravlje monitoring (SHM) tehniku kao bez razaranja testova koje se mogu primeniti za detekciju oštećenja, lokalizaciju i kvantitativno državnih struktura. Ova tehnika zasniva na istraživanjima dinamičkih karakteristika objekata da otkriju štetu kroz njihove operativne stanja radnog veka. Predloženi SHM Postupak se utvrdi na četiri vrste čeličnih strukturnih modela; jednostavno podržali ispust zraka; rešetka most, Verendeel most i model višespratnica. Predloženi SHM postupak je usvojila izmene u dinamičkih karakteristika, prirodnog učestalosti i načina oblika, strukturnih modela, koji su izvađeni iz eksperimentalne modalne analize i procenjene od numeričke analize modalni. Eksperimentalno ispitivanje se sprovodi pomoću simulaciju ambijentalnih vibracija merenja od najuzbudljivijih strukturne modele šejker uređaja sa generiše vibracije signalom. Dinamički odgovor, samo izlaz, strukturnih modela su snimljeni korišćenjem 8- ubrzanja i 8-channle uređaj sticanje. Eksperimentalni modal osobine strukturnih modela su izdvojite pomoću Artemis odsisnog softvera pika metodom branje frekventnom domenu razlaganja (FDD) tehnikom. Numerička simulacija strukturnih modela su modelira konačnih elemenata Model (MKE) koristeći ANSIS paket Softvare bi ANSIS Parametric Design Jezik (APDL). Numeričke modal svojstva strukturnih modela se procenjuju pomoću ANSIS softver za blok algoritam metodom dinamičke analize modalne za izotropnoj elastične linearno tipa strukturni modeli. U analizi FE, dva tipa elementa se primenjuju na FEM da se analiziraju strukturne modele, Beam4 i Mass21 tip elementa. Predloženi SHM Postupak se vrši pomoću vještačka inteligencija tehnika (AIT), koji se primenjuje u ovoj studiji pomoću funkcije na tzv metodu heuristike optimizaciju za otkrivanje oštećenja i njihove karakteristike, lokacije i ozbiljnost, u strukturnim modelima. Predloženi SHM postupak usvaja heurističkog optimizaciju simuliranog kaljenja (SA) metoda u AIT. Predloženi SHM procedura se kreira pomoću višu stručnu računara jezik MATLAB softvera životne sredine za te svrhe. U ovoj studiji, modifikovani cilj funkcija je usvojen u SA metode optimizacije uključiti osetljive modalni parametri za promenu u savijanja krutosti strukturnog modela usled prisustva štete. Predloženi cilj funkcija sastoji XII kombinaciju razlika u modalnih frekvencija i modalne raseljavanja vektora strukturnih modela. Predloženi SHM postupak obuhvata proces kalibracije, koji se realizuje za početnu FE modela za podešavanje numeričke ažuriran FE višenamenskih karakteristika strukturnih modela sa onima ekstrahuje eksperimentalno. Što više značajni parametri su odabrani da ažuriraju model FE tokom procesa kalibracije koristeći predlog SHM postupak sa naznakom funkcije cilja. Usvojeni cilj funkcija za proces kalibracije uključuju samo Visokoosetljivi modal parametar prirodnih frekvencija strukturnih modela. Konačni rezultati modalnih osobina kalibriranu FE modela imaju značajnu približavanja koji odgovara modalnih osobina eksperimentalnim strukturnih modela. Predloženi SHM Postupak se utvrdi na usvojenim četiri strukturnih modela stvarajući drugačije oštećenja scenarija, šteta lokacije i odnosi oštećenja. Konačni rezultati su pokazali da su performanse predložene SHM postupku ima robustnost i visoku efikasnost za detekciju tačno ili veoma bliske štete, lokacije i prostiranje provedenih oštećenja scenarija. Snažan predloženog SHM postupka dolazi iz visoke efikasnosti u heurističkog metode optimizacija SA sa svojim karakteristikama koje daje globalnu optimalnu vrednost sa brzim konvergencije u malom procentu proverene rešenja u potrazi prostora. Izuzetni rezultati verifikacije predloženog postupka SHM koristeći SA metod podrazumeva sposobnost postupka za identifikaciju štete za sve vrste jednostavnih i složenih strukturnih modela . Pored toga , predloženi SHM postupak se može primeniti za prave civilnim strukturama u operativnom stanju na sajtu sa visokom pouzdanošću , i efikasnosti i efektivnosti za detekciju oštećenja kao bez razaranja.

The presented thesis studied proposed a novel procedures that was implemented to develop a Structural Health Monitoring (SHM) technique as non-destructive tests that can be applied to detect damage, localization and quantification of civil structures. This technique based on investigations of dynamic characteristics of the structures to detect the damages through their operational conditions of service life. The proposed procedure was built using Artificial Intelligence Technique (AIT) under concept of the methods of damage detection based on updating FE model using heuristic optimization methods. The proposed SHM procedure Using Simulated Annealing heuristic optimization methos was shortened to "SHMUSA-procedure". The SHMUSA-procedure was verified on four types of steel structural models; simply supported overhang beam; grid bridge, Verendeel bridge and Multi-storey building model to prove reliability, efficiency and robustness under various dynamic behaviours. The SHMUSA-procedure was adopted the changes in dynamic characteristics, natural frequency and normalized mode shape vector, which are extracted from experimental modal analysis and estimated from numerical modal analysis of the damage scenario for structural models. and their characteristics, location and severity,. The experimental testing is implemented using simulation of ambient vibration measurements by exciting the structural models by shaker device using generated vibration signal. The dynamic response, output only, of the structural models are recorded using 8- accelerometers and 8-channel acquisition device. Experimentally, the modal properties of the structural models are extracted by ARTeMIS extractor software using Frequency Domain Decomposition (FDD) technique by peak picking method. The numerical simulation of structural models are modeled in Finite Element Model (FEM) using ANSYS package software by ANSYS Parametric Design Language (APDL). Numerically, the modal properties of structural models are estimated by ANSYS software using block Lanczos method of dynamic modal analysis for isotropic elastic linear structural models type. The Finite Element Analysis (FEA) is performed using three element types in the FE models, Beam4, Shell63 and Mass21, to analyze the four structural models. IX The SHMUSA-procedure is created using high technical computing language of MATLAB environmental software for that purposes. In this procedure, the modified objective function is adopted in the SA optimization method to include the sensitive modal parameters to change in flexural stiffness of the structural model due to presence of damages. The proposed objective function in the SHMUSA-procedure consists combination of differences in modal frequencies and normalized mode shape vectors of the structural models. The SHMUSA-procedure includes the calibration process, which is implemented on the initial FE model to tune the modal properties estimated numerically with those extracted experimentally of the structural models. The more significant parameters are selected to update the FE model during calibration process using the SHMUSA-procedure with specified objective function. The adopted objective function for calibration process include only the high sensitive modal parameter of natural frequencies of the structural models. The final results of the modal properties of the calibrated FE model have significant convergence corresponding to the modal properties of the experimental structural models. The proposed SHM procedure is verified on the adopted four structural models by creating different damage scenarios, damage locations and damage ratios. The final results indicated that the performance of proposed SHM procedure has robustness and high efficiency to detect exactly or very close the damages, locations and extents of the implemented damage scenarios. The powerful of the proposed SHM procedure comes from the high effectiveness of the heuristic optimization SA method with its features which gives the global optimum value with quick convergence in small percentage of checked solutions of searching space. The excellent results of the verification of the proposed SHM procedure using SA method means the capability of the procedure to identify damages for all types of simple and complex structural models. In addition, the proposed SHM procedure can be applied for real civil structures during operational condition in site with high reliability, and efficiency and effectiveness for damage detection as a non-destructive testing. X

Dugoročne promene u stohastičkoj strukturi hidroloških vremenskih serija

Long-term changes in stochastic structure of hydrolagic time series

Hidrološki proces moguće je analizirati kao stohastički proces na osnovu koga se donosi zaključak o njegovoj unutrašnjoj stohastičkoj strukturi. Struktura hidrološkog procesa predstavlja bitnu osobinu na osnovu koje se dobijaju informacije o njegovoj vremenskoj zakonomernosti. Dugoročne promene u strukturi hidrološkog procesa predstavljaju značajno pitanje savremene nauke. Isto tako, važna istraživačka pitanja predstavljaju i matematičko opisivanje hidroloških procesa, opisivanje njihove uzročno-posledične veze sa meteorološkim parametrima, kao i predviđanje dugoročnih promena hidroloških procesa. Osnovni cilj ovog rada je razvoj metodologije kojom se analiziraju dugogodišnje promene u hidrološkim serijama. U doktorskoj disertaciji su predložene metodologije za formiranje stohastičkih modela za kratkoročne i dugoročne projekcije godišnjih i mesečnih protoka. Metodologija za kratkoročne projekcije godišnjih i sezonskih protoka se zasniva na dekompoziciji vremenskih serija na trend, periodičnost, stohastičku i slučajnu komponentu, po uzoru na metodu TIPS koju je predložio Jevđević (1984). Predložena metodologija je nazvana modifikovana TIPS metoda. Vremenska serija se deli na deterministički deo koga čine linearni trend i višegodišnja periodičnost. Drugi deo predstavlja stohastička komponenta koja se modelira autoregresionim modelima višeg reda. Modifikacija TIPS metode se sastoji u identifikaciji makroperiodične komponente na uglačanim godišnjim i sezonskim serijama proticaja tehnikom LOESS. Na ovaj način se uklanjaju oscilacije visoke frekvencije i olakšava identifikacija makroperiodične komponente koja je od prevashodnog značaja za razmatranje dugoročnih promena u hidrološkim nizovima. Ovako uspostavljen model se koristi za kratkoročne projekcije godišnjih proticaja tako što se determinističke komponente ekstrapoluju, vrši se prognoza stohastičke komponente i određuje interval poverenja prognoziranih proticaja. Za razliku od kratkoročnih projekcija koje se dobijaju pomoću modela zasnovanog na unutrašnjoj strukturi serija protoka, za dugoročne projekcije mesečnih proticaja predložen je model koji koristi zavisnost proticaja od padavina i temperatura. Cilj XIX modela jeste da se omogući njegova primena za dugoročne projekcije proticaja na osnovu klimatskih scenarija. Primenom analize osetljivosti protoka na glavne meteorološke faktore, utvrđeno je da na mesečne proticaje najviše utiču mesečne padavine. Takođe, dugoročne promene u proticajima su posledica postojanja istih promena u padavinama. Drugi uticajni faktor je temperatura, zbog čega je odlučeno da se model za dugoročne projekcije zasniva na zavisnosti protoka od padavina i temperatura. Za dugoročne projekcije protoka predložen je model SDTS, kojim se mesečni proticaji dele na deterministički deo sastavljen iz kompozitnog nelinearnog trenda, makroperiodične i sezonske komponente. Drugi deo je stohastički baziran na transfer funkcijama sa dvostrukim ulazom (padavinama i temperaturama) na mesečnoj vremenskoj skali. Ostatak serije čini potpuno slučajna komponenta. Prve dve determinističke komponente u predloženom modelu SDTS (nelinearni trend i makroperiodična komponenta) se modeliraju na godišnjem nivou, dok se preostale komponente modeliraju na mesečnom nivou. Pored modela SDTS, kao pomoćni model, razvijen je inicijalni model godišnjih proticaja zasnovan na transfer funkcijama sa godišnjim padavinama i temperaturama kao ulaznim vremenskim serijama. Ovaj model omogućava dugoročnu prognozu trenda i makroperiodične komponente na godišnjem nivou. Primena modela SDTS sa dugoročnim projekcijama padavina i temperatura iz klimatskih modela je moguća ukoliko se obezbedi ekstrapolacija svih komponenti modela u budućnost. U predloženom modelu komponente su ekstrapolovane na različite načine: (1) Nelinearni trend i makroperiodična komponenta za budućnost su dobijene na osnovu simuliranih godišnjih proticaja inicijalnim modelom sa padavinama i temperaturama iz klimatskih scenarija na godišnjem nivou; (2) Sezonska komponenta u budućnosti je formirana na osnovu pretpostavke da će se unutargodišnji ciklus proticaja u budućnosti menjati u skladu sa promenom unutargodišnjeg ciklusa padavina; (3) Stohastička komponenta za budućnost je rezultat primene modela transfer funkcija na mesečnom nivou sa mesečnim padavinama i temperaturama iz klimatskih scenarija. XX

Hydrological time series is analysed as a stochastic process that is utilized to make an inference according to the internal stochastic structure. The stochastic structure of a hydrological process presents the main characteristic that is used to obtain information about its realization pattern through the time. The long-term change in the structure of hydrological process presents essential issue of contemporary science. Also, the important research questions are mathematical modeling of hydrological process, its cause-consequence relation with meteorological variables and prediction of a long-term change of hydrological process. The aim of this research is to develop the methodology used to analyse the long-term projections in hydrological time series. In the doctoral dissertation the methodologies for constituting stochastic models for the short-term and long-term projection of annual and monthly flows are proposed. The methodology for short-term projection of annual and seasonal flows is based on decomposition of time series on trend, periodical component, stochastic and random component inspired by TIPS method proposed by Yevjevich (1984). The proposed methodology is called the modified TIPS method. The time series is divided into two parts: the deterministic part which is constituted of linear trend and long-term periodicity and the stochastic component is modeled by autoregression models of higher orders. The modification of the TIPS method consists of identification of macroperiodical component of annual and seasonal flows by using the LOESS technique. In this manner, the high-frequency oscillations are removed. This fact is facilitated identification of long-term periodical component which is of fundamental significance for consideration of long-term changes in hydrological time series. The established model is used for the short-term projection of annual flows by extrapolation of deterministic component, the projection of stochastic component and determining the confidence interval of projected flows. In contrary to the short-term projections determined by using the model based on internal structure of flow series, the model based on relations among flows, XXII precipitations and temperatures is proposed for a long-term projection of annual flows. The aim of the model is to provide the application of long-term projection of flows in accordance with climatic scenarios. The Application of sensitivity analysis of flow using the main meteorological factors is determined by the precipitations as the major influental parameter on flows pattern. Moreover, the long-term changes of flow time series are the consequence of the same multi-decadal changes in precipitations. The second influential parameter is temperature. Due to this fact, the model for long-term projection is considered to be constituted by using the relation among the flows, precipitations and temperatures. For the long-term projection the proposed SDTD model is used for decomposition of the monthly flow series into the deterministic part composed of composite non-linear trend, macroperiodical component and seasonal component. The second part is stochastic component modeled by the Transfer Functions with multiple inputs (precipitation and temperature) on monthly time scale. The first two deterministic components of the proposed SDTS model (non-linear trend and macroperiodical component) are modeled at the annual level, while the rest of the components are modeled by using a monthly time scale. In addition to the SDTS model, the Initial model of annual flows is developed as an auxiliary model based on Transfer Functions with annual precipitations and temperatures as input time series. This model provides the long-term projection of trends and macroperiodical component at annual level. The application of the SDTD model with long-tem projections of precipitations and temperatures from climatic models is possible under conditions provided by extrapolation of all model’s components in the future. In the proposed model the components are extrapolated by employing different manners: (1) Non-linear trend and macroperiodical component in the future are determined by using the simulated annual flows which are modeled with precipitations and temperatures from climatic model at annual time scale, (2) Seasonal component in the future is formed on the assumption that the interannual flows will be changed according to the interannual changes of precipitations, (3) Stochastic component in the future is result of the Transfer Function model on monthly time scales with monthly precipitations and temperatures from the climatic scenarios. XXIII

Analiza perzistentnosti i divergentnosti tekućeg računa u evropskim ekonomijama metodama panela

Analysis of persistence and current account divergence in the European economies by panel methods

Visok spoljnotrgovinski deficit predstavlja najveći izazov za eksternu ravnotežu. Velik broj zemalja se suočava sa rastućom divergencijom trgovinskih tokova i uravnotežen tekući bilans se pre može smatrati kao retkost, nego kao pravilo u ekonomskoj praksi. Nakon izbijanja globalne finansijske i ekonomske krize, nejednakosti zemalja u pogledu kretanja tekućeg računa su postale sve intenzivnije. Jedna od značajnijih implikacija datih trendova jeste perzistentna eksterna neravnoteža koja varira u zavisnosti od meĎunarodne pozicije zemlje, trgovinske otvorenosti, unutrašnjih performansi i sposobnosti da se apsorbuju različiti eksterni šokovi. U tom smislu, predmet istraživanja doktorske disertacije odnosi se na analizu perzistentnosti i ispitivanje divergentnih trendova tekućeg računa u članicama Evropske unije u periodu 1995-2015. godine. Ideja je da se primenom panel tehnika ispita uticaj pojedinačnih faktora na trgovinsku neravnotežu i, konačno, oceni stepen perzistentnosti tekućeg računa. Prevashodno, upotrebljeni su dinamički modeli panela kako bi se ocenio uticaj odabranih determinanti na kretanje tekućeg računa u zemalja članicama Evropske unije u periodu 1995-2015. godine, sa ciljem provere prve hipoteze koja podrazumeva ispitivanje stepena perzistentnosti tekućeg računa. Nakon toga, imajući u vidu značaj održivosti tekućeg računa u dugom roku, prilikom analize determinanti tekućeg računa izvršena je podela na strukturne i ciklične komponente, što je značajno sa aspekta sagledavanja prirode eksterne neravnoteže. Za potrebe analize uticaja strukturnih faktora na dinamiku tekućeg računa u srednjem roku formirani su petogodišnji proseci podataka, dok je ocena cikličnih determinanti sprovedena na podacima koji predstavljaju jednogodišnja odstupanja od petogodišnjih proseka. Rezultati primene uopštenog metoda momenata i metoda kvazi maksimalne verodostojnosti ukazali su da su saldo bilansa tekućih transakcija u zemljama Evropske unije u velikoj meri odredili sledeći faktori: kretanje tekućeg računa iz prethodnog perioda, fiskalni bilans, stopa rasta GDP-a, stepen trgovinske otvorenosti, strane direktne investicije i odnosi razmene iz grupe makroekonomskih faktora, odnosno stopa rasta populacije, stopa zavisnosti stanovništva prema godinama starosti, odobreni krediti privatnom sektoru i pokazatelj efikasnosti vlade iz kategorija demografskih, finansijskih i institucionalnih komponenti.

The high current account deficit is the biggest challenge for the external balance. A large number of countries are facing with a growing current account divergence and a balanced current account is considered more as a rarity than as a rule in economic practice. After the outbreak of the global financial and economic crisis, inequality between countries in terms of the current account developments has become more intense. One of the major implications of this trends is persistent external imbalance, which varies depending on the international position of the country, trade openness, internal performance and the ability of the country to absorb various external shocks. To this end, the purpose of a doctoral dissertation is related to the analysis of the persistence and divergent trends in the current account in the Member States of the European Union during the period 1995-2015. The idea is to examine the impact of individual factors on the trade imbalance by using panel data econometric methods, as well as to estimate the degree of persistence of the current account. Primarily, dynamic panel models are used in order to assess the impact of selected determinants on the current account movement in the Member States of the European Union during the period 1995-2015, with the aim of testing the first hypothesis which involves the examination of the degree of the current account persistence. After that, given the importance of current account sustainability in the long run, current account determinants are divided into structural and cyclic components, which is important in terms of assessing the nature of external imbalances. Five-year averages of data are formed for the analysis of the impact of structural factors on the dynamics of the current account in the medium term, while the estimation of impact of cyclical determinants was carried out on data which represent annual deviations from the five-year averages. Estimation results of dynamic panel data models obtained by generalized method of moments and the method of quasi maximum likelihood pointed out that main determinants of current account balance in the European Union were as follows: movement of the current account from the previous period, fiscal balance, GDP growth rate, degree of trade openness, foreign direct investment and terms of trade from the group of macroeconomic factors, and population growth rate, age dependency ratio, approved loans to the private sector and indicator of government effectiveness from the category of demographic, financial and institutional components.

Geosistemske osnove upravljanja životnom sredinom

Geosystem foundations of environmental governance

Naslovom disertacije, teorijskim okvirom i predmetom istraživanja ukazuje se na interesovanje u disertaciji, a to je geografski teorijski koncept i sama suština geografije kao nauke (proučavanje interakcija društva i prirode), jer upravo taj geografski identitet određuje i životnu sredinu kao pojam (fenomen). Ako se o životnoj sredini razmišlja kao o složenom i višedimenzionalnom sistemu, odnosno o ekološkim problemima kao o multiskalarnim i multisektorskim problemima, pretpostavlja se da u proučavanju datih fenomena posebno mesto ima geografsko mišljenje i geografska logika. Primenom geosistemskog pristupa metodološki je „eliminisano” odvojeno proučavanje društvenih i prirodnih sistema jer su oni u stvarnosti povezani. To polazište omogućava da se sagleda funkcionalna, prostorna i vremenska međuzavisnost unutar sistema životne sredine. Na tim osnovama (sagledavanje interakcija) se mora graditi sistem upravljanja životnom sredinom kao nezaobilazna strateška aktivnost usmeravanja procesa u životnoj sredini. Iz ideje o interakcijama, odnosno geosistemskom pristupu, proističe integralni pristup kao vodeći princip u rešavanju multiskalarne i multisektorske prirode ekoloških problema, odnosno princip na kome se zasniva upravljanje životnom sredinom. Promena u percepciji/definisanju ekoloških problema, od redukcionističkog ka sistemskom poimanju, sa naglaskom na interakcijama, uticala je na prelazak sa „vladanja na upravljanje”. To je značilo otklon od paradigme „zapovedaj i kontroliši” ka fleksibilnijim modelima upravljanja. Integralni princip pretpostavlja integraciju politika (sektorska integracija), nivoa upravljanja (teritorijalna integracija) i učesnika (podela odgovornosti između države i privatnog sektora, nevladinih organizacija i dr.), kao i mera i instrumenata u sistemu upravljanja životnom sredinom, što je prikazano u disertaciji. Interdisciplinarnost (prirodna i društvena komponenta), metodološki pluralizam, geografski koncepti (prostor, mesto i životna sredina), istorijsko geografski retrospekt, samo su neka od obeležja geografskog mišljenja koja su našla svoju primenu u proučavanju životne sredine. U disertaciji je potvrđena uloga prostornog planiranja kao veoma značajnog instrumenta za integrisanje ciljeva zaštite životne sredine u politike prostornog razvoja.

The title of thesis, the theoretical framework and the research subject indicate that the thesis focuses on the theoretical concept of geography and the essence of geography as a science (the study of interactions between society and nature). This is because the environment as a concept (phenomenon) is determined by a geographical identity. If the environment is perceived as a complex and multi-dimensional system and ecological problems are interpreted as multiscale and multisectoral issues, it is assumed that a particularly important place in the study of these phenomena is occupied by geographical reasoning and a geographical logic. The reliance on a geosystem-based approach "eliminates", methodologically, the study of social and natural systems as unrelated subjects, because they are in fact closely related. This approach enables us to grasp the functional, spatial and temporal interrelationships in the environment. It is upon these foundations (understanding of interactions) that an environmental governance system must be built as a crucial strategic activity aimed at channelling various processes in the environment. The integrated approach, as the leading principle in dealing with multiscale and multisectoral nature of environmental problems and the principle of environmental governance, is derived from the idea of interactions, i.e. from a geosystem-based approach. The changed perception/definition of ecological problems, involving a transition from a reductionist to a systemic approach, with an emphasis on interactions, has led to a shift from "government to governance". This implied a departure from the "command and control" paradigm and the adoption of more flexible governance models. The principle of integration involves the integration of policies (cross-sectoral integration), levels of governance (territorial integration) and stakeholders (sharing responsibilities among the public and private sectors, non-governmental organizations, etc.), as well as environmental governance measures and instruments, as demonstrated in thesis. Interdisciplinarity (taking into account both natural and social components), methodological pluralism, geographical concepts (space, place and environment) and historical and geographical retrospection, are merely some of the features of geographical reasoning that are applied in environmental research. The role of spatial planning, as a very important instrument for integrating environmental protection goals into spatial development policies, is confirmed in thesis.

Višekriterijumska analiza kvaliteta vazduha u urbanim sredinama u zavisnosti od vremenskih faktora

Multicriteria analysis of air quality in urban areas depending on climatic factors

Beograd, glavni grad i najveća urbana jedinica u Srbiji, ima ozbiljne probleme povezane sa saobraćajnim gužvama u drumskom saobraćaju, jer nema razvijenu saobraćajnu mrežu usklađenu sa stvarnim potrebama. Beograd sa okolinom pripada zoni visoke koncentracije stanovnika i karakterišu ga relativno homogena geografska, kulturološka, istorijska i druga obeležja. Prirodni položaj Beograda je jedinstven u Evropi – grad se nalazi na ušću velikih reka Dunava i Save, a u kontaktnoj zoni južnog oboda ravničarskog Panonskog bazena i severne ivice Balkanskog poluostrva. Grad ima složenu morfološku strukturu, kako onu osnovnu - prirodnu, tako i sadašnju, nastalu složenim transformacijama i razvitkom nasleđenog gradskog tkiva. Merenja koncentracija zagađenja supstancama (SO2, NOx, Dim-a), meteoroloških podataka (temperatura, vlažnost vazduha, brzina vetra, oblačnost) i protoka saobraćaja su sprovedena u okviru urbane zone Beograda, u ulicama tzv kanjona tipa, u vremenskom periodu od 1996. do 2010. godine. Obrada pojedinih parametara je sprovedena kako bi se razmotrili i identifikovali izvori zagađenja vazduha u centralnoj zoni grada, sa posebnim osvrtom na ulice tzv kanjona tipa.

Belgrade, the capital and the largest urban unit in Serbia, has serious problems connected to road traffic jam due to undeveloped road system network related to real needs. Belgrade with the hinterground belongs to a zone of high concentration of inhabitants. It is characterised by relatively homogenous geographical, cultural, historical and other features. The natural position of Belgrade is unique in Europe – the townsite is located on the conflux of two big rivers the Danube and the Sava. The location lies within the zone of the south perimeter of The Panonian plain and the northern ridge of the Balkan peninsula. The city has a complex morphological structure – the basic natural and the present – appeared by the complex transformations and by development of inherited city structure. Measuring of pollutants concentration (SO2, NOx, Smoke), meteorological data (temperature, air humidity, wind speed, heighth of clouds) and the traffic flow have been carried out within the urban part of Belgrade in streets of so called canyon type, in the period of time from the year 1996 to 2010. Processing of certain parameters have been carried out in order to consider and identify sources of air pollution within the city central zone.