118 research outputs found

    ENVIRONMENTAL ASSESSMENT OF THE HYDRAULIC STRUCTURES BY VARIOUS ARTIFICIALIZATION PARAMETERS

    Get PDF
    Abstract. The natural rivers and their flood areas are among the most complex and diverse ecosystems in the world. Traditional structural solutions in river training works are focused on basic requirements as flood protection, littoral zone protection, river bed protection, providing the space for economic development. In this study a method of anticipated assessment of certain physical impact of designed river training works is presented, perceived as global effect of river bed artificialization. The method mainly serves to compare the various possible solutions of river training works, based on the „artificialization parameter” also named „global impact GI”. Key words: river training works, environmental cost

    ANN Model for Prediction of Rockfill Dam Slope Stability

    Get PDF
    Dam safety and potential failure is one of the issues with the highest risk in water resources management. The dam slope stability is adversely influenced by the natural seepage process in the dam. Thus, monitoring of the pore and total pressures in the dam core is essential in the seepage process analysis. It is possible during the dam operation period to have one or more cells malfunctioning, after years of operation. Sometimes it is technically not possible to replace the cell or the costs of the replacement are too high and not economically justified. At the Pridvorica Dam, several instruments - cells for pore and total pressure monitoring malfunctioned. The objective of this study is to develop a neural network model for the prediction of the pore and total pressure on the malfunctioning cells and to demonstrate its quick and effective practical application for identifying complex non-linear relationship between the input and output variables. The proposed approach can be a very helpful tool for modeling of the stochastic behavior of the dam in order to give adequate warning of soil pressures to prevent failures

    High Embankment Dam Stability Analysis Using Artificial Neural Networks

    Get PDF
    Regular surveillance, data acquisition, and visual observation of high embankment dams are extremely important for the stability analysis of these structures. The stability issues that could occur during a dam\u27s lifetime are mainly related to slope instability and internal erosion. The aim of continuous dam security monitoring and field measurement is to identify priority flow paths in the dam body, i.e. cracks and the erosion process. A key parameter for embankment dam stability assessment is the pore water pressure (PWP) response in the clay core. Increasing pore water pressure results in shear strength reduction and can cause dam instability. In this paper, four different models based on artificial neural networks will be developed for pore water pressure prediction in an embankment dam clay core, based on meteorological, hydrological, and geotechnical data. These models will be compared and the model that gives the smallest prediction error will be presented. In the light of climate change, the main objective of this paper is to find the model that can be used for embankment dam stability prediction in extreme weather events

    TRADE SECRETS - SECURITY AND LEGAL ASPECT

    Get PDF
    The struggle for the dominance of competition is increasingly being transferred from physical to virtual arena, and therefore the application of new technologies is becoming an increasingly important basis for faster development, but it is becoming increasingly important weapon in the struggle for the dominance of competition in the new (digital) economy. The aforementioned trends in the foreground are even more emphasized than they were in the past years, the need to improve the protection of intellectual property, and the enhancement of the protection of trade secrets from increasingly intense industrial espionage and increasingly frequent cyber attacksIt is this trend that has been mentioned and initiated to pay special attention to the analysis of the possibilities and potential possibilities for improvement of the security and legal system of protection of sent secrets as an integral part of the intellectual propert

    Factors Influencing Dental Fear in Students of Biomedicine

    Get PDF
    Background: Dental fear is a reaction of an individual to actual or potential painful/harmful procedures in dental practice. There is large variation in reports of dental fear prevalence among university students, implying existence of different factors that influence occurrence of dental fear in various populations. Objective: The aim of the study was to investigate putative factors that may influence extent of dental fear among university students of biomedicine. Methods: This study was designed as cross-sectional investigation. In total, 113 students on study courses on the 3rd, 4th, 5th year of dentistry, and on the 4th, 5th and 6th year of medicine undergraduate program were surveyed at the Faculty of Medical Sciences, University of Kragujevac, Serbia. Fear of dentist was measured by the Dental Fear Survey and other variables were generated by questionnaire with questions about socio-demographic characteristics of the participants. Results: Students of biomedicine surveyed in this study did not suffer from dental fear in great extent (median value on the scale was close to the lower limit: 29.5. The only factor that increased risk for developing dental fear in our study was previous traumatic experience with a dentist. Conclusion: Dental fear is not very prevalent among biomedical students. However, main risk factor for dental fear in general population, previous traumatic experience with a dental intervention, also remains primary risk factor in population of biomedical students

    Neki biološki parametri grdobe (lophius budegassa spinola, 1807) u vodama Crne Gore (jugoistočni Jadran)

    Get PDF
    U ovom istraživanju obrađene su 264 jedinke grdobe (LophiusbudegassaSpinola, 1807), od kojih su 128 (ili 48,5%) bili mužjaci, 114 (43,2%) ženke, dok kod 22 jedinke (8.3%) nije bilo moguće odrediti spol. Odnos ženki i mužjaka bio je 1:1,12. Omjer spolova (SR) procijenjen je na 47,1. Testiranje uzorka χ2-testom pokazalo je da ne postoji statistički značajna razlika između broja mužjaka i ženki u uzorku (χ2 = 0.8099, p > 0.05). Totalna dužina (TL) jedinki u uzorku kretala se od 15,6 do 67,0 cm, sa prosječnom vrijednošću od 29,2 ± 8,1 cm (prosječna dužina ± standardna devijacija). Shapiro-Wilkesov test normalnosti pokazao je da distribucija dužinskih frekvencija ukupnog uzorka nije pratila normalnu distribuciju (W = 0,9003; p < 0,05), kao ni distribucija mužjaka (W = 0,9563; p < 0,05) ni ženki (W = 0,8959; p < 0,05). Raspon dužina kod ženki varirao je 18,8 do 67,0 cm TL, sa prosjekom od 31,9 ± 9,6 cm TL. Prosječna dužina mužjaka bila je 82,3 ± 5,7 cm TL, dok su minimalna i maksimalna dužina bile 16,6 cm i 48,4 cm TL. Prosječna masa jedinki u uzorku bila je 444,15 ± 427,24 g, sa rasponom od 57,14 g do 3000,00 g. Masa ženki kretala se od 114,50 g do 3000,00 g, sa srednjom vrijednošću od 584,10 ± 557,15 g. Najmanja izmjerena masa mužjaka bila je 66,70 g, a najveća 1791,96 g, sa prosjekom od 372,40 ± 249,28 g. Analiza dužinsko-masenog odnosa pokazala je vrijednost parametra b manju od idealne izometrijske vrijednosti 3, što znači brži rast jedinki u dužinu od povećanja mase, odnosno da jedinka sa rastom dobiva izduženiji oblik tijela. Vrijednosti parametra b po spolovima su također bile manje od 3. Studentov t-test pokazao je da se parametar b dužinsko-masenog odnosa kod ukupnog uzorka i ženki statistički značajno razlikovao od vrijednosti 3, dok kod mužjaka to nije bio slučaj. Dužina prve spolne zrelosti (Lm50%) ukupnog uzorka procijenjena je na 26,37 cm TL, odnosno 30,50 cm TL kod ženki i 26,26 cm TL kod mužjaka.Procijenjene su i dužine pri kojima 25% (Lm25%), odnosno 75% (Lm75%) populacije dosegne spolnu zrelost, kao i parametri α i β krivulje zrelosti

    Ranking institutions within a university based on their scientific performance: A percentile-based approach

    Get PDF
    Over the recent years, the subject of university rankings has attracted a significant amount of attention and sparked a scientific debate. However, few studies on this topic focus on elaborating the scientific performance of universities’ institutions, such as institutes, schools, and faculties. For this reason, the aim of this study is to design an appropriate framework for evaluating and ranking institutions within a university. The devised methodology ranks institutions based on the number of published papers, mean normalized citation score (MNCS), and four percentile-based indicators using the I-distance method. We applied the proposed framework and scrutinized the University of Belgrade (UB) as the biggest and the best-ranked university in Serbia. Thus, 31 faculties and 11 institutes were compared. Namely, an in-depth percentile-based analysis of the UB papers indexed in the Science Citation Index Expanded (SCIe) and the Social Science Citation Index (SSCI) for the period 2008-2011 is provided. The results clearly show considerable discrepancies in two occasions: first, when it comes to the question of leading author, and second, when it comes to analyzing the percentile rank classes (PRs) of groups of faculties

    Biološke karakteristike inćuna (engraulis encrasicolus) u Bokokotorskom zalivu (Crna Gora)

    Get PDF
    Inćun, Engraulis encrasicolus, je jedna od najrasprostranjenijih i komercijalno najvažnijih vrsta riba u Jadranskom moru (FishStat Plus, FAO). Industrijski ribolov srdele i inćuna u Crnoj Gori je još uvek nerazvijen, pa se ove vrste uglavnom love alatima malog obalnog ribolova, tj. mrežama potegačama male veličine okaca (5-6 mm) u Bokokotorskom zalivu kao i malim mrežama plivaricama na ulazu u zaliv. Podaci predstavljeni u ovom radu rezultat su istraživanja sprovedenog u okviru Pilot studije AdriaMed projekta u periodu septembar 2007. – avgust 2011. godine. Tokom Pilot studije putem intervjua sa ribarima prikupljane su informacije o ulovu i ribolovnom naporu svih aktivnih tipova brodova, a takođe su uzimani i biološki uzorci komercijalno važnih vrsta kako bi se proučavale njihove biološke karakteristike. Uzorci inćuna prikupljeni su u području Bokokotorskog zaliva (Sl. 1) koji predstavlja jedno od najproduktivnijih područja na crnogorskom primorju, pa je mrestilište i hranilište mnogih ribljih vrsta. Uzorci su prikupljani mesečnom dinamikom. Prikupljeni su sledeći podaci: totalna dužina tela sa preciznošću 0.1 cm, totalna težina sa preciznošću 0.01 g, pol i stadijum zrelosti gonada (upotrebljena je skala sa četiri stadijuma zrelosti, 1 – nezrele, 2 – sazrevanje, 3 – zrele i 4 – izmrešćene jedinke). Na osnovu ovih podataka određen je dužinski raspon, distribucija dužinskih frekvenci, odnos polova, GSI, dužina dostizanja polne zrelosti (L50% dužina pri kojoj je 50% populacije polno zrelo, kao i L25% L75%), kao i dužinsko-težinski odnos prema formuli log W=log a+b log LT. Inćun je bio najzastupljeniji u ulovu u septembru i aprilu. Dužinski raspon iznosio je od 7.5 do 14.4 cm, sa srednjom vrednošću od 10.13 cm, dok je težinski raspon bio od 0.9 do 21 gram, sa srednjom vrednošću 6.4 g. Od ukupnog broja jedinki (2000) ženke čine 61%, mužjaci 33%, a 6% su jedinke kojima nije bilo moguće odrediti pol. Ženke su zastupljenije od mužjaka u svim dužinskim klasama, osim na 8 cm dužine gde je odnos polova 1:1. Najveći broj uzorkovanih jedinki bio je u drugom stadijumu zrelosti. Procenjeno je da je dužina pri kojoj 50% populacije inćuna dostigne polnu zrelost 9.1 cm, dok su L25% i L75% procenjeni na 8.6 i 9.7 cm. Koeficijent b dužinsko-težinskog odnosa kod mužjaka iznosio je 3.212, a kod ženki 3.437

    Alergenski proteini u ribi

    Get PDF
    Riba predstavlja znatan deo ishrane ljudi u svetu. Pre svega, riba je značajan izvor proteina (15-24%) visoke biološke vrednosti, bogata je mineralima, vitaminima, a posebno esencijalnim masnim kiselinama za koje je dokazano da pogoduju u prevenciji mnogobrojnih oboljenja. Zbog velikog značaja polinezasićenih masnih kiselina n-3 klase, u Evropi su date i preporuke o optimalnom dnevnom unosu. Međutim, pored hranljivih svojstava koje ima, riba može biti i izvor različitih bioloških i hemijskih opasnosti. Od bioloških opasnosti posebno su značajni paraziti (Trematodae, Nematodae, Cestodae), bakterije (Salmonella spp, E. coli, Vibrio parahemolyticus, Vibrio vulnificus, Listeria monocytogenes, Clostridium botulinum, Staphyloccocus aureus), virusi (Norwalk virus, Entero virusi, Hepatitis A, Rotavirus) i biotoksini. Najznačajnije hemijske opasnosti su policiklična aromatična jedinjenja, histamin i teški metali (živa, olovo, kadmijum, arsen, gvožđe). Alergije usled konzumiranja pojedinih vrsta namirnica su u porastu poslednjih godina. Veliki pokret oko pravilnog načina ishrane je doveo do toga da ljudi sve češće konzumiraju ribu, proizvode od ribe kao i različite plodove mora. Pored različitih opasnosti koje mogu poticati iz ribe, posebni značaj poslednjih godina se daje ribi kao potencijalnom alergenu. Naime, veliki broj alergija koje se javljaju u svetu pripisuju se alergenima koji potiču iz mesa ribe, pre svega proteinima mesa ribe. Učestalost alergija koje se povezuju za unosom mesa ribe varira u Evropskim zemljama (Norveška 1,5%; 2,3% Turska, 2,3% Grčka; Švedska 1.2-3.2 %). Kao najznačajniji proteinski alergen iz mesa ribe navodi se parvalbumin (ß tip), koji je izolovan kod velikog broja vrsta. Smatra se da su šaran i bakalar najčešći izvori parvalbumina koji se dovodi u vezu sa različitim vidovima alergijskih reakcija. Potencijalni alergeni su takođe kolagen i želatin koji su izolovani iz kože i pojedinih organa riba. Takođe, značajan alergen iz plodova voda je i tropomiozin, arginin kinaza, aldolaza. Pored ovih alergena, značajni alergeni mogu da potiču iz ikre, pojedih vrsta kavijara, a opisani su slučajevi gde su alergijske reakcije povezane sa kolagenom koji se nalazi u ekstracelularnom matriksu proteina. Alergeni koji dovode do različitih alergijskih reakcija, pored proteina mesa ribe, mogu poticati i od gotovih proizvoda od ribe. Tu spadaju različiti panirani proizvodi od ribe koji sadrže celer, gluten i druge dodatke koji mogu biti potencijalni alergeni. Zbog značaja koji imaju na zdravlje ljude, tehnologija je omogućila različite metode za detekciju ovih alergena. Kao neke od njih navode se ELISA (Enzyme-linked immunosorbent assay), RAST (Radioallergosorbent test) i RIE (Rocket Immuno-electrophoresis). Koja će se metoda detekcije primeniti, prvenstveno zavisi od dostupnosti alergena i praga njegove detekcije. Industija mesa je razvojem tehnologije uvela pojedine tehnološke prosece koji imaju mogućnost inaktivacije pojedinih alergena, pre svega proteina mesa ribe. Visoke temperature koje se primenjuju u obradi mesa ribe mogu uticati na ove alergene, tako što će smanjiti alergeni potencijal, dok neki tehnološki postipci nemaju tu mogućnost
    corecore