Croatian Digital Dissertations Repository
Not a member yet
10487 research outputs found
Sort by
Rad ne sadrži naslov na drugom jeziku.
No full textOvaj rad istražuje povezanost financijske pismenosti s ulaganjem u kriptovalute. S obzirom na nedostatak dosadašnjih istraživanja u ovom području, rad nastoji premostiti te praznine i analizirati kompleksne veze između financijske pismenosti i ulaganja u kriptovalute. Istraživanje se temelji na modelu koji analizira utjecaj financijske pismenosti na čin ulaganja u kriptovalute, zatim na ponašanje dionika kriptovalutnog tržišta te na očekivanja i ciljeve ulaganja. Kroz kritički pregled relevantnih radova, rad predstavlja inovativan pristup kombiniranjem objektivno i subjektivno mjerene financijske pismenosti te strukturalnog modeliranja za analizu složenih odnosa. Rezultati istraživanja pokazuju da povećanje obje vrste financijske pismenosti pozitivno utječe na ulaganja u kriptovalute, uz istaknuti utjecaj na ponašanje investitora na tržištu kriptovaluta. Također, primijećene su razlike u motivima ulaganja između financijski pismenijih i manje pismenih investitora. Istraživanje je provedeno anketnim upitnikom od veljače do srpnja 2023. godine na uzorku od 445 ispitanika na hrvatskom financijskom tržištu. Analiza uzorka otkriva da osim financijske pismenosti, sociodemografske varijable dob i spol također imaju značajan utjecaj na posjedovanje kriptovaluta. Osim toga, modeliranjem strukturalnim jednadžbama otkriveno je da visoki prihodi i subjektivna financijska pismenost imaju značajan pozitivan utjecaj na količinu financijske imovine uložene u kriptovalute. Daljnja analiza ukazuje da veći stupanj financijske pismenosti vodi široj diverzifikaciji portfelja tradicionalnom i alternativnom imovinom, uključujući i kriptovalute. Razlike u ponašanju investitora otkrivene su kroz različite strategije ovisno o razini objektivne i subjektivne financijske pismenosti. Analiza utjecaja financijske pismenosti na motivacijske aspekte ulaganja u kriptovalute, otkriva da objektivno financijski pismeniji investitori ističu veće očekivane performanse odnosno brže postizanje financijskih ciljeva ulaganjem u kriptovalute, dok subjektivno financijski pismeniji cijene znanje i resurse za korištenje kriptovaluta. Među ciljevima ulaganja dominantan je FOMO efekt, dok su mogućnosti ostvarivanja visokog profita, decentraliziranost i jednostavnost pristupa kriptovalutnom tržištu glavni motivatori ulaganja među specifičnostima razvoja kriptovalutnog tržišta. Motivacijski čimbenici djelomično su potvrđeni razlikama između financijski pismenijih i manje pismenih investitora.This study explores the connection between financial literacy and cryptocurrency investments. Given the lack of prior research in this area, the paper seeks to fill these gaps and analyze the complex relationships between financial literacy and cryptocurrency investments. The research is based on a model that analyzes the impact of financial literacy on cryptocurrency investment decisions, stakeholder behavior in the cryptocurrency market, as well as investment expectations and goals. Through a critical review of relevant literature, the paper presents an innovative approach by combining objectively and subjectively measured financial literacy and structural equation modeling to analyze complex relationships. The research findings indicate that an increase in both types of financial literacy positively influences cryptocurrency investments, with a notable impact on investor behavior in the cryptocurrency market. Differences in investment motives are also detected between more financially literate and less literate investors. The study was conducted through a survey from February to July 2023, with a sample of 445 participants in the Croatian financial market. Sample analysis reveals that, in addition to financial literacy, sociodemographic variables such as age and gender also significantly impact cryptocurrency ownership. Furthermore, structural modeling reveals that high income and subjective financial literacy have a significant positive impact on the amount of financial assets invested in cryptocurrencies. Further analysis suggests that a higher level of financial literacy leads to broader portfolio diversification with traditional and alternative assets, including cryptocurrencies. Differences in investor behavior are uncovered through various strategies depending on the level of objective and subjective financial literacy. Analyzing the impact of financial literacy on motivational aspects of cryptocurrency investment reveals that objectively financially literate investors emphasize higher expected performance or faster achievement of financial goals through cryptocurrency investments. On the other hand, subjectively financially literate individuals value knowledge and resources for utilizing cryptocurrencies. The Fear of Missing Out effect is a dominant investment goal, while the possibilities of achieving high profits, decentralization, and ease of access to the cryptocurrency market are key motivators among the specific features of cryptocurrency market development. Motivational factors are partially confirmed by differences between more financially literate and less literate investors
Primary realization of the temperature scale from the triple point of argon to the triple point of water
No full textPouzdanost i sljedivost mjerenja niskih i kriogenih temperatura uvjet je o kojem ovise mnoge
grane industrije i znanosti, no zbog specifičnosti mjerenja niskih temperatura, mjeriteljska
infrastruktura najviše razine u tom području u Republici Hrvatskoj još nije razvijena. U sklopu
ovog doktorskog istraživanja razvijen je etalonski sustav za primarnu realizaciju temperaturne
ljestvice ITS-90 u području od trojne točke argona (- 189,3442 °C) do trojne točke vode
(0,01 °C), čime je napravljen značajan iskorak u smjeru proširenja i ojačanja mjeriteljskih
kapaciteta najviše razine. U radu je detaljno opisana važeća Međunarodna temperaturna
ljestvica ITS-90, s pregledom postojećih sustava i praktičnih smjernica za njenu realizaciju te
je zaključno opisan neizostavan postupak procjene mjerne nesigurnosti. Eksperimentalni dio
istraživanja proveden je u Laboratoriju za procesna mjerenja na Fakultetu strojarstva i
brodogradnje Sveučilišta u Zagrebu (FSB-LPM), krovnoj instituciji u području mjeriteljstva
temperature, vlažnosti i tlaka. Fokus eksperimentalnog dijela rada bio je na razvoju sustava za
realizaciju trojne točke argona s novim automatskim regulatorom tlaka dušika u kriostatu. U
radu je prikazan razvoj novog automatskog regulatora tlaka s pripadnim softverom za
upravljanje i prikupljanje mjernih podataka. Uz to, razvijen je i novi sustav za punjenje uložnog
otvora za termometar unutar fiksne točke argona helijem te novi sustav za praćenje temperature
i razine tekućeg dušika u kriostatu. Rad prikazuje rezultate probnih realizacija trojne točke
argona s novim regulatorom, temeljem kojih je provedena optimizacija i usklađivanje svih
komponenti etalonskog sustava. Definirana je eksperimentalna metoda za realizaciju trojne
točke argona kojom se postiže dulji plato s manjim nagibom u usporedbi sa sustavom s ručnom
regulacijom tlaka, a što je posljedica preciznije i stabilnije regulacije tlaka. U sklopu
istraživanja opisan je i matematički model realizacije temperaturne ljestvice te je procijenjena
ukupna mjerna nesigurnost realizacije. Bilateralnom usporedbom s Laboratorijem za
metrologiju in kakovost na Fakultetu za elektrotehniku Sveučilišta u Ljubljani (MIRS/ULFE/
LMK) u području od trojne točke argona (-189,3442 °C) do trojne točke vode (0,01 °C),
potvrđena je funkcionalnost i mjerne sposobnosti etalonskog mjernog sustava razvijenog u
sklopu ovog doktorskog istraživanja.Reliability and traceability of low and cryogenic temperature measurements are crucial factors
for many branches of industry and science, which are in need for support through a significant
strengthening of the metrology infrastructure for calibration of thermometers at temperatures
below -40 °C. Due to the specifics and complexity of low-temperature measurements, the
highest metrology infrastructure in this part of the temperature range has not been developed
so far in the Republic of Croatia. As part of this doctoral research, a standard measurement
system for the primary realization of the ITS-90 temperature scale in the range from the triple
point of argon (-189.3442 °C) to the triple point of water (0.01 °C) was developed, which is a
significant step forward in the direction of expanding and strengthening of metrology capacities
at the highest level.
The doctoral dissertation is structured as follows.
In the theoretical part of the research, the historical development of the temperature scales is
described together with the recent redefinition of the kelvin and its impact on the temperature
metrology. Although the temperature is currently defined through the fundamental Boltzmann
constant, the ITS-90 temperature scale still remains the best approximation of the
thermodynamic temperature. Therefore, the theoretical part focuses on the International
Temperature Scale from 1990, providing a detailed description of practical guidelines for its
implementation. The theory of measurement uncertainty analysis, essential to all
measurements, is also presented.
The experimental part of the research was carried out in the Laboratory for Process
Measurements at the Faculty of Mechanical Engineering and Naval Architecture, University
of Zagreb (FSB-LPM), which acts as a Croatian national calibration laboratory for temperature,
humidity, and pressure. The focus of the experimental part of the work was on the development
of a system for realizing the argon triple point with a new automatic pressure control system
for a liquid nitrogen cryostat. The work presents the development of a new automatic pressure
controller with associated software for control and acquisition of measurement data. In
addition, a new system for filling the thermometer well, inside the argon fixed point, with
helium was developed, as well as a new system for monitoring the temperature and level of
liquid nitrogen in the cryostat.
Following this, the research focuses on an extensive mathematical model for realization of the
ITS-90 temperature scale. The measurement uncertainty analysis of the realisation has been
conducted. All of the influencing parameters have been investigated, and the uncertainty
contributions have been estimated. The expanded measurement uncertainty of the realization
has been calculated. The coefficients of the deviation function for the temperature probe used
for interpolation between the fixed points in the range from - 189,3442 °C to 0,01 °C have been
determined, together with the associated uncertainty of interpolation.
Lastly, the final chapter presents the results of this doctoral thesis and follows with a discussion
and conclusion. Through a trial realization of the triple point of argon with the manual pressure
regulator, the needed improvements were identified. The presented results of trial realizations
of the argon triple point with a new controller, served as a basis for optimization and
coordination of all components of the measurement system. An extensive investigation of the
characteristics of the new controller has been performed and the characteristics of the manual
and automatic pressure regulation were compared. An experimental method for realizing the
argon triple point was defined, utilizing automatic pressure regulation of higher precision and
stability, which ensures a longer temperature plateau with a smaller slope compared to a system
with manual pressure regulation. A bilateral comparison with the Laboratory for Metrology
and Quality at the Faculty of Electrical Engineering, University of Ljubljana
(MIRS/UL- FE/LMK) in the temperature range from the triple point of argon (-189.3442 °C)
to the triple point of water (0.01 °C) confirmed the functionality and measurement capabilities
of the primary calibration system developed in the scope of this doctoral research.
To conclude, the scientific contributions achieved through this research are as follows:
A new pressure control system was developed for automatic adjustment of the nitrogen
pressure in the argon triple point cryostat. This system is more flexible, stable, and accurate
than the manual regulator, which makes it possible to achieve an argon triple point plateau with
a longer duration and smaller slope.
An experimental procedure was developed for the realization of the triple point of argon with
automatic control of the nitrogen pressure in the cryostat, which made it possible to realize up
to three triple point plateaus of satisfactory duration and slope, with only one filling of the
cryostat with liquid nitrogen.
The new measurement system was developed for independent primary temperature realization
from the temperature of triple point of argon (-189.3442 °C) to the temperature of triple point
of water (0.01 °C) with measurement uncertainties of the realization of 1.85 mK in the triple
point of argon and 1.54 mK at the triple point of mercury, expressed at the 95% confidence
level (k=2). The stated realization uncertainties were confirmed through successful
participation in a bilateral comparison with an equivalent standard system whose measurement
capabilities in the subject area are internationally recognized.
Through the scientific contributions made, it is evident that by using the results of experimental
measurements, along with the characterization and optimization of individual components, a
unique measurement system has been developed for the primary realization of the ITS-90
temperature scale in the temperature range from the triple point of argon to the triple point of
water, with realization uncertainties of less than 5 mK (k=2). This confirms the hypothesis of
the doctoral research
Promjenjivost stanja slanosti voda obalnog vodonosnika pod utjecajem operativnih režima melioracijskog sustava, plimotvornih oscilacija i hidroloških uvjeta rijeke Neretve : disertacija
No full textOne of the areas of prior interest for the Republic of Croatia in terms of water conservation and water needs, especially for irrigation of agricultural crops, is the river Neretva delta. This area represents the largest agricultural area on the Croatian coast and is the source of existence for the local population. Managing the area has become a complex task given the intensive agricultural activities, the large number of people living near the area of interest, significant seawater intrusion (SWI) and ongoing climate changes manifested by indicators such as sea level rise and increasingly unpredictable precipitation. Therefore, the need to understand the processes responsible for creating favorable/unfavorable conditions in both, surface and groundwater, is self-evident. A review of the available literature reveals that SWI in the coastal aquifer system of the Neretva Valley, with a focus on external loadings and their effect on ground and surface water has not been sufficiently investigated. The influence of the operative regime of the melioration system, the hydrological regime of the river Neretva and the tidal characteristics of the Adriatic Sea to ground and surface water fluctuations along the study area was established as the primary scope of this thesis. A variety of methodological approaches was used throughout the thesis to analyze and investigate the impact of SWI on the Neretva coastal aquifer system. Despite the strong effect of the SWI, the area of interest is defined as a complex system that can be controlled naturally or by management. In order to investigate the interaction between factors controlling the surface and ground water along the Neretva Valley in conjunction with SWI, a monitoring system was designed and implemented to collect pertinent data sets and time series. An investigation was conducted utilizing time series in the temporal and frequency domains. The application of cross correlation methods, the Discrete Fourier Transform and the Continuous Wavelet Transform provided insights into the interdependence of analyzed ground and surface water parameters. Based on past in-situ work and time series of sea water elevation and piezometric head, the study area was hydrogeologically characterized. Previously collected in-situ data were used for the conceptualization of the coastal aquifer system. Tidal methods were upgraded to incorporate tidal signals with more than one harmonic constituent to improve the method’s capacity. Findings are focused on determining specific storage, hydraulic conductivity and leakance between shallow unconfined and deeper confined aquifer units. Novel in-situ and laboratory results were utilized to bolster these findings. The confinement of the deeper aquifer was confirmed in two ways: i) by using frequency analysis of constituents typical for confined conditions which confirm confinement of deeper aquifer and ii) by using ERT results which do not evidence the absence of confining clay layer along the study area. The determined values of hydraulic conductivity were consistent with the gravely material, which was confirmed by interpreting the characteristic grain values determined in the laboratory from borehole cores taken from the study area. Based on the hydrogeological characterization and determination of the connectivity between the geological units of the aquifer, the predominant SWI corridors characterizing rain and dry seasons were identified. To comprehend the transient nature of surface and groundwater parameters such as temperature, piezometric head, and electrical conductivity, a number of external loadings were considered. The confined aquifer appears to maintain its electrical conductivity regime independently from the unconfined aquifer above and vice versa. The electrical conductivity in the confined aquifer shows no significant correlation with tidally-induced oscillations, while piezometric head as observed within the confined aquifer is shown to be driven by tidal oscillations. In addition to the confined aquifer, it was demonstrated that the Adriatic Sea is the dominant factor controlling the groundwater regime in the Diga area, as found in the unconfined aquifer. The melioration system’s operative regime creates favorable agricultural conditions in the study area. As a result, groundwater has been delineated below sea levels, thereby creating active SWI conditions that increase the inflow of seawater from the Adriatic Sea. The majority of precipitation occurs during the rain season, which creates an imbalance in the natural aquifer recharge. In both rain and dry seasons, the river Neretva's hydrological regime plays a dominant role but with opposite effects. During the dry season, seawater intrudes upstream along the Neretva riverbed, generating a source of seawater that impacts the Jasenska region. Specific attention has been given to the sub melioration systems of Vidrice and Opuzen ušće. The groundwater of the coastal area of Opuzen ušće, called Diga, was identified as dominantly tide controlled, while the Vidrice area is predominantly influenced by the presence of upstream springs of brackish water which enter the melioration system. It was discovered that only the Vidrice area has higher salinity during the rain season than during the dry season. The operative regime of the melioration system controls the dynamics of water quality as found along the Vidrice area, while the groundwater in the Jasenska area is salinized primarily by the Neretva River.Jedno od područja od primarnog interesa za Republiku Hrvatsku u smislu očuvanja stanja voda i potreba za vodom primarno za potrebe navodnjavanja poljoprivrednih kultura jest područje donje Neretve, točnije, područje delte rijeke Neretve od grada Opuzena do Jadranskog mora. Područje donje Neretve predstavlja najveće poljoprivredno područje na hrvatskoj obali, a za lokalno stanovništvo koje značajan postotak primarni izvor prihoda osigurava iz poljoprivrednih djelatnosti, predstavlja izvor egzistencije. Do sredine 20.tog stoljeća, u većoj mjeri močvarno područje, sa značajnim vodoprivrednim i infrastrukturnim zahvatima i objektima pretvoreno je u područje pogodno za poljoprivredne djelatnosti. S obzirom na intenzivnu poljoprivredu, značajnu koncentraciju ljudi koji žive u području koje gravitira području od interesa, utjecaja intruzije morske vode (IMV) uslijed blizine mora i klimatskim promjenama za očekivati je u bližoj budućnosti značajne poteškoće u pogledu dugoročnog održanja kvalitete vode prihvatljive za navodnjavanje poljoprivrednih kultura. Iz pregleda dostupne literature uočava se nedostatak cjelovitog istraživanja u segmentu IMV, nedostatak razumijevanja vanjskih utjecaja, operativnog režima sustava, sustava obrane od poplava i identifikacije glavnih koridora unosa morske vode u obuhvat. Kako bi se analizirao proces IMV-a i utjecaj IMV-a u dolini Neretve u radu su primijenjeni razni metodološki pristupi. Kako bi se istražio proces IMV-a, ali i procesi koji utječu na IMV u području interesa, osmišljen je i implementiran sustav monitoringa površinskih i podzemnih voda. Prikupljeni podaci su analizirani u vremenskoj i frekvencijskoj domeni primjenom crosskorelacijskih modela, diskretne Fourier-ove transformacije i kontinuirane Wavelet transformacije u svrhu analiziranja parametara podzemnih i površinskih voda, ali i njihove međusobne povezanosti. S obzirom na prethodne geofizičke i geomehaničke istražne radove definiran je konceptualni model vodonosnika doline Neretve. Vremenske serije razine mora i potencijala u vodonosniku korištene su u svrhu hidrogeološke karakterizacije vodonosnika pod tlakom. Metode iz domene Tidal Methods se unaprjeđuju s kapacitetom obrade realnih polikromatskih signala plime i oseke, a sve u svrhu pouzdanijeg određivanja hidrogeoloških parametara poput parametra zapremine, hidrauličke vodljivosti i procjeđivanja između dubokog vodonosnika pod tlakom i plitkom vodonosnog sloja sa slobodnim vodnim licem. Utvrđeni hidrogeološki parametri su verificirani s geofizičkim, geomehaničkim i laboratorijskim rezultatima. Karakterizacija dubokog vodonosnika pod tlakom potvrđena je analizom karakterističnih konstituenata u vodonosniku pod tlakom u frekvencijskoj domeni i ERT rezultatima koji ukazuju na neprekinutost glinenog sloja između plitkog i dubokog vodonosnog sloja. Verifikacija dobivenih vrijednosti hidrauličke vodljivosti vodonosnika pod tlakom je provedena usporedbom s rezultatima analiziranih uzoraka materijala iz istražne bušotine napravljene na području interesa. S obzirom na prethodno utvrđene hidrogeološke parametre i utvrđene ograničenosti vodonosnika pod tlakom, definirani su glavni koridori unosa morske, ali i svježe vode u područje interesa u kišnom i sušnom razdoblju. Kako bi se dodatno razumjele vremenski promjenjive karakteristike površinskih i podzemnih voda poput razine podzemne ili površinske vode, električne vodljivosti i temperature analizirani su razni vanjski utjecaji. Električna vodljivost u vodonosniku pod tlakom ima relativno konstantnu vrijednost tokom cijele godine, dok su promjene potencijala u vodonosniku uzrokovane plimotvornim oscilacijama mora. Osim utjecaja na duboki vodonosnik oscilacije razine mora imaju i dominantni utjecaj na režim podzemnih voda u vodonosniku sa slobodnim vodnim lice na području Dige. Rad infrastrukture navodnjavanja i odvodnje primarno definira režim podzemnih voda u smislu osiguranja zone pedološkog sloja. Ova činjenica, iako primarno zamišljena s idejom osiguranja povoljnih poljoprivrednih uvjeta, za posljedicu je imala i kreiranje uvjeta za ostvarenje aktivne intruzije morske vode, te povećan unos morske vode u obalni vodonosni sustav i intenziviranje IMV-a u ovom području. Tokom godine većina pale oborine se ostvari u kišnom razdoblju što za posljedicu ima disbalans u režimu površinskih i podzemnih voda. Hidrološki režim rijeke Neretve ima ključnu ulogu na stanje podzemnih voda u području Jasenska i u kišnom i sušnom razdoblju. U sušnom razdoblju prisutnost klina morske vode u rijeci Neretve je čini slanim rubnim uvjetom, dok je u kišnom s povećanjem protoka i potiskivanjem klina morske vode prema ušću zabilježen suprotan utjecaj rijeke Neretve na područje Jasenska. Za razliku od Jasenske, područje Dige je dominanto pod utjecajem mora, a područje Vidrica je pod utjecajem slanih izvora koji se nalaze uz rub ovog područja te zaslanjuju melioracijske kanale na ovom području. Područje Vidrice predstavlja jedino područje u obuhvatu koje ima veću slanost podzemnih i površinskih voda tokom kišnog razdoblja u odnosu na sušno razdoblje. Režim rada melioracijskog sustava kontrolira kvalitetu vode na području Vidrica, a rijeka Neretva ima glavni utjecaj na zaslanjivanje područja Jasenska
Determination of the Western Herzegovina and Southern Dalmatia karst spring water origin based on natural and artifical tracers : doctoral thesis
No full textKompleksni hidrogeološki slijevni sustav južne Dalmacije i zapadne Hercegovine površine preko 2300 km2, predmet je dugogodišnjih hidrogeoloških istraživanja, koja su detaljno analizirana za potrebe izrade ovog doktorskog rada. No, ranija istraživanja nisu uključivala istodobno praćenje većeg broja izvora u obje države kako bi se odredilo podrijetlo izvorskih voda ovoga područja. U dosadašnjim istraživanjima sljevovi pojedinih izvora su se preklapali u velikoj mjeri, što je ukazalo na potrebu za delineacijom, što ujedno predstavlja temelj za mnogobrojne hidrogeološke analize poput određivanja zaliha podzemnih voda, izrade karata ranjivosti ili izrade karata poplavnih hazarda, izračuna vodne bilance. Isto tako, po prvi su put obavljena i istraživanja stabilnih izotopa kisika 18 (δ18O), deuterija (δ2H) i sumpora 34 (δ34S), kako bi se odredila starost vode te podrijetlo povišenih koncentracija sulfatnih iona. Hidrogeološka istraživanja trajala su od rujna 2013. godine do rujna 2020. godine i uključivala su primjenu više različitih metoda, što je rezultiralo novim saznanjima o ovom krškom podzemnom sustavu i njegovoj interakciji s oborinama, površinskom i morskom vodom. Na terenu su automatskim mjeračima mjereni temperatura, elektrolitička vodljivost i razine podzemne vode, mjereni su protoci na nekoliko lokacija te su in situ mjereni fizikalno-kemijski pokazatelji. Uzorci podzemne i površinske vode prikupljani su na 31 lokaciji za laboratorijsko određivanje ionskog sastava. Rađena je i analiza stabilnih izotopa kisika 18 (δ18O), deuterija (δ2H) i sumpora 34 (δ34S) u različitim hidrološkim uvjetima, kako bi se protumačile i sezonske promjene. Na terenu je provedeno i simultano trasiranje dvama traserima te su prikupljani podataci o oborinama i protocima te mikrobiološkim pokazateljima. Rezultati su ukazali kako je najveći dio područja napajanja u zapadnoj Hercegovini, manji dio u neposrednom zaleđu, a konačna zona istjecanja u južnoj Dalmaciji. Ukazano je i kako voda većinski prolazi kroz karbonatne naslage, a prema rezultatima analize stabilnih izotopa δ34S djelomično i kroz evaporitne stijene permotrijaske starosti. Rezultati ukazuju i kako se vodonosnik obnavlja s oborinskom vodom te se radi o izrazito mladoj vodi, na brzo dreniranje zbog izrazite okršenosti terena, i na moguće antropogene izvore u vodi (gnojiva, otpadne vode). Delineirano je šest podsljevova ili utjecajnih površina, što je i prikladniji opis, jer se podzemne vode u nekim hidrološkim uvjetima dokazano kreću preko naznačenih granica.The complex hydrogeological transboundary catchment of Southern Dalmatia and Western Herzegovina, located in two neighbouring countries, Croatia and Bosnia and Herzegovina, covers an area of 2300 km2. In addition to numerous previous hydrogeological studies, a new research was carried out from September 2013 to September 2020 for the purpose of this thesis. During this period monthly sampling of five spring and surface water locations in Western Herzegovina, 20 locations of spring and surface water in Southern Dalmatia and six locations of spring and surface water at Baćina lakes was performed. Additional research included hydrogeological mapping, a simultaneous tracing experiment (on September 30th and October 2nd, 2014), and stable sulphur δ34S analyses from SO4- ions in water samples, taken during hydrological maximum (April) and minimum (October) of 2019 at ten locations. The study area is composed of sedimentary rocks of Permian, Triassic, Jurassic, Cretaceous, Palaeogene, Neogene and Quaternary ages. The oldest, Upper Permian rocks have been tectonically uplifted to the surface through diapirism and reverse faulting N of the studied catchment area and consist of evaporitic rocks with some carbonate and clastic rocks (sandstones and marls) interbeds. Hydrogeologically they could potentially represent a barrier to groundwater flows, but since they occur outside of the study area they do not influence hydrogeological relationships. However, a very locally restricted diapir in the northern part of the study area as well as extraordinary high sulphur concentrations at some locations indicate probable diapiric uplifts also in the studied area. Triassic deposits, in large part composed of dolomites, form partial barriers to water circulation within the study area. Jurassic rocks, dolomites and limestones. Cretaceous deposits, mostly composed of bedded to massive limestones with rare dolomites prevail in this area. Palaeogene and Neogene deposits consist of a wide range of lithologies, but clastic rocks (mostly sandstones and marls) predominate, especially Eocene flysch deposits which have a diverse impact on groundwater movement. Quaternary deposits cover numerous karst poljes, as well as areas along streams and rivers. The most permeable rocks in the study area are Mesozoic limestones and dolomites, while the least permeable rocks belong to flysch and Quaternary deposits. A complex underground conduit system and extreme karst forms heterogeneity are typical for the study area, characterised by very variable relief from mountains and hilly parts, river valleys and karst poljes to the Adriatic coast. The study area can be divided into five or six hypsometric levels. The first or the lowest level is the discharge zone almost at the sea level. iii This zone extends from Gradac and the nearby coastal karst spring Mandina Mlinica, across the Baćina Lakes and the Klokun 1 spring to the Neretva River valley and its marginal karst springs Prud, Modro oko, Čeveljuša, and several smaller springs. Vrgoračko polje is part of the second level (25 m a.s.l.) and Rastok polje of the third level (70 m a.s.l.). The fourth level includes springs in the Trebižat–Mlade–Tihaljina River valley in Bosnia and Herzegovina (120–180 m a.s.l.), while the fifth level, the highest one, stretches across the Imotski–Bekija polje (260 m a.s.l.). In the nortwesteern part, the fifth level comprises the wider area of the Posuško polje (570–620 m a.s.l.), but the highest part of the area around the Rakitno polje (900 m a.s.l.) could be separated as the sixth level. The study area is abundant in high-quality spring water, of which only a small amount is used for public water supply. Over a hundred temporary and permanent karst springs occur in the area with annual discharge of the largest springs (Klokun 1, Butina, Modro oko, Borak, Vrelo Tihaljine, Prud, Opačac, Klokun 2) ranging from 1.5 to over 10 m3/s. Rivers Ričina, Suvaja, Sija, Vrljika, Tihaljina, Sita, Mlade and Trebižat actually represent the same river characterized by repeated springing, flowing on the surface, sinking, and underground stream sections, along its 106 km long course from the highest spring to its confluence with the Neretva River. Most of the surface waters in the area flow towards the Neretva River, but part of groundwaters flow southwards. The recharge zone of this large catchment area is predominantly in Bosnia and Herzegovina, whereas the final discharge zone is along the Croatian coast and Neretva River valley. During the study for this thesis an integrated hydrogeological map of the whole catchment area has been made by combining four basic geological maps and attributing specific hydrogeological characteristics to all geological units. Furthermore, further delineation of the catchment boundaries and the catchment area was performed, which is an extremely complex task in the karst areas. In order to define external and internal boundaries of such a large and complex catchment area different methods were used, including detailed study of all available geological and hydrogeological data, hydrogeochemical properties of individual springs, hydrological data, and tracing tests data combined with water balance calculated in previous reports. Out of a large number of reviewed studies and published papers on the study area very few of them included the simultaneous monitoring of a large number of springs in both countries. In addition, a simultaneous tracer test was carried out for the purpose of this thesis. iv Since some of the previously determined groundwater connections confirmed by tracing experiments were cutting previously defined groundwater boundaries within some of the subcatchments, it became evident that a new definition of some subcatchments should be introduced. Up to now there were no research of stable isotopes of oxygen 18 (δ18O), deuterium (δ2H) and sulphur 34 (δ34S) within the study area. Those natural stable isotopes are especially important for the determination of the water age and origin, especially in areas where artificial tracing is not feasible at the scale of the regional catchments. Moreover, as evaporite diapirs crop out in the vicinity of the study area and increased levels of sulphur were determined at some studied locations, it was assumed that some diapirs exist in the shallow underground of the research area in contact with groundwater paths, enriching Southern Dalmatia and Western Herzegovina groundwater with sulphate ions. Hence, for the first time in the study area, stable δ34S isotopes from sulphate ions in water samples were analysed to determine their origin. Therefore, the conducted hydrogeological investigations of the studied large catchment area were carried out using several methods to fulfil all the objectives of this thesis. The methods used included: 1) measurements of various water parameters, such as temperature, electrolytic conductivity, and water level measurements with automatic loggers, 2) in situ measurements of physico-chemical parameters, 3) water sampling and laboratory analyses for the determination of the ion composition, 4) analyses of δ18O, δ2H and δ34S stable isotopes, 5) flow measurements, 6) simultaneous tracing with artificial tracers, and 7) collection of available data on precipitation, discharge and microbiological parameters. Delineation of a large and complex karst catchment into six subcatchments from which surface and groundwater flow in different directions was the main result of this thesis. Subcatchments are defined according to their specific geological setting and hydrogeological relations, but their boundaries should not be considered as strict water divides because groundwater or surface water may intersect them during different hydrological conditions. Yet, they are fundamental for water balance calculations and estimating influence on even distant karst springs. Furthermore, new term redefining subcatchments as influential areas was introduced. The proposed term can be used for the description of comparable large karst catchments characterised by interaction between subcatchments. In such subcatchments groundwater fluctuates depending on the water table levels affected by changes in precipitation. Given the hydrogeological conditions during late winter and spring, when the snow melts and v precipitation significantly increases, groundwater often discharges across the defined boundaries. Therefore, the term subcatchment in this case, as in most of the Dinaric karst terrains, can only be used tentatively for easier understanding of the topic, while the term influential area could be far more appropriate. Results of stable δ34S isotopes composition from the measured sulphate ions were compared with the Permian evaporites δ34S isotope curves from the literature, which supports the possible sulphate ions origin from permian evaporites in Western Herzegovian and Southern Dalmatian groundwaters. Since the main recharge area of the studied large system is located in Western Herzegovina and the final discharge zone in Southern Dalmatia, the groundwater mostly passes through karstified carbonate rocks prevailing in the entire area, but is probably partly influenced by underground deposits of evaporite rocks that were probably uplifted close to the surface in the form of diapirs. Results of stable isotops analyses of sulphur from the sulphate ion in different hydrological conditions indicate a rapid reaction of the system to precipitation and mixing of dissolved sulphate from evaporites (mostly gypsum) with rainwater and possibly polluted water (sewage water). The presented comprehensive hydrogeological study has shown that the studied system has a zone of underground and surface runoff (sometimes intertwined) between the the Neretva River valley and hydrogeological barrier of flysch deposits along the Adriatic coast. Furthermore, research indicated that most of the studied major springs recharge from the same aquifer in their hinterland. Higher concentrations of sulphate ions in several springs of the Southern Dalmatia also indicate recharging from more distant areas – mainly W and N of Trebižat–Mlade–Tihaljina River, where evaporite rocks are cropping out and where the domination of sulphate ions in water was documented. Seawater impact was recorded in some coastal springs and surface waters, indicating fresh–seawater interaction. Such springs are located closer to the flysch barrier edge, in contact with permeable carbonates. Further to the east, the effect of underground penetration of the seawater decreases. In addition, multivariate mathematical cluster analysis of hydrogeochemical data shows two main clusters within the system, lithogeochemical cluster and marine cluster, while multivariate mathematical factor analysis separated three factors – seawater influence factor, carbonates and evaporates dissolution factor, and biological/chemical reactions factor. Determined three main hydrochemical facies within the investigated area (calcium–hydrogen carbonate facies, calcium–sulphate/hydrogen carbonate facies, and sodium–chloride facies) reflect the chemical response of lithology and groundwater flow pattern. vi Physico-chemical parameters of spring waters indicate shorter water retention time and domination of conduit flow, whereas recession curve analysis indicates rapid drainage of the aquifer due to immense karstification. Time-series data (cross-correlation analysis) indicates a rapid response to precipitation. All aforementioned analyses provided insight into the main aquifer characteristics and represented a basis for the interpretation of δ34S stable isotope data. Obtained results could improve the quality of the establishment of sanitary protection zones, as the new tracing experiment proved that the groundwater has much higher apparent velocity than considered previously, as well as better management of the, studied and similar transboundary catchments, which can often be challenging due to differences in development and policies between different countries. Thesis could be of great importance for the future management of this transboundary catchment because ensuring high-quality groundwater is crucial for sustainable development and protecting the ecosystem integrity of each country. In conclusion, the local and regionally important scientific contribution of the Ph.D. Thesis is manifested in: (1) Detailed determination of Southern Dalmatia and Western Herzegovina transboundary catchment area hydrogeological properties; (2) Newly proposed delineation of the studied large and complex karst catchment; (3) Establishing a new classification of subcatchments as influential areas applicable to other complex karst terrains; (4) Introducing sulphur δ34S stable isotope analysis as an important research methodology fa or complex karst catchment area of the Outer Dinarides
Amfifilni konjugati masnih kiselina i piridilporfirina u fotodinamičkoj terapiji na staničnim linijama melanoma
No full textAmphiphilic porphyrins are widely used photosensitisers (PSs) in photodynamic therapy
(PDT), an antitumor treatment in which the PS is combined with light irradiation of
appropriate wavelength and oxygen in the vicinity within the treated lesions to induce the
cytotoxic effect and consequently tumour destruction. In addition to their beneficial
properties as antitumour agents, they are also used to treat viral, bacterial or fungal infections.
The hydrophobic parts of the molecule facilitate the passage through the membrane bilayer,
while the hydrophilic parts enable water solubility and thus the possibility of easier
administration of the PS. Although the amphiphilic porphyrins have shown great efficacy as
PSs, the hydrophilic-lipophilic balance, which utilises all the advantageous properties of this
type of PSs and avoids the disadvantages such as aggregation or low cellular uptake, is
somewhat less studied.
The main goal of this doctoral thesis was to study the hydrophilic-lipophilic balance on
different groups of asymmetric A3B pyridylporphyrins and its content is divided into four
parts. In the first part, N-methylated (pyridinium-3-yl) porphyrins and Zn(II) analogues with
alkyl chains of different lengths (7-17 C-atoms) were compared. The Zn(II)-porphyrin with
a 13 C-atom alkyl chain showed the highest cytotoxicity and selectivity towards the
melanoma cell line when irradiated with orange light. The second part involved the synthesis
of amphiphilic N-oxidised pyrid-3-ylporphyrins, where porphyrins with a 13 and 17 C-atom
chain showed to be promising against melanoma cell line, diminishing the melanin
obstruction. In the last part, amphiphilic (pyridinium-3-yl)porphyrins were chelated with
68Ga(III) and natGa(III) to obtain the PET/PDT agents, and their distribution was analysed in
PET-CT scan. It was found that the hydrophilic-lipophilic balance not only affects
cytotoxicity and selectivity in vitro, but also exhibits differential biodistribution in vivo.
These findings on A3B pyridylporphyrins will give us a deeper insight into the importance
of the amphiphilicity of the molecule and lead us to the further development of an “ideal PS”
for use in PDT.Amfifilni porfirini su široko korišteni fotosenzibilizatori (PS-ovi) u fotodinamičkoj terapiji
(PDT), antitumorskom tretmanu u kojem se PS kombinira sa svjetlošću odgovarajuće valne
duljine i kisikom u blizini liječenih lezija kako bi se izazvao citotoksični učinak i posljedično
uništenje tumora. Osim što se koriste kao antitumorski ljekovi, također je poznata njihova
upotreba protiv virusnih, bakterijskih i fungalnih infekcija. Hidrofobni dijelovi u molekuli
olakšavaju prolazak kroz membranski dvosloj, dok hidrofilni dijelovi omogućuju topljivost
u vodi, a time i mogućnost lakše administracije PS-a. Iako su amfifilni porfirini pokazali
veliku učinkovitost kao PS-ovi, ravnoteža hidrofilnih i lipofilnih dijelova, koja omogućava
sva povoljna svojstva i izbjegava nedostatke kao što su agregacija ili niska stanična
internalizacija, manje je izučavana.
Glavni cilj ovog doktorskog rada bio je proučavanje ravnoteže hidrofilnih i lipofilnih dijelova
različitih skupina asimetričnih A3B piridilporfirina, podijeljenih u četiri dijela. U prvom
dijelu uspoređeni su N-metilirani (piridin-3-ij)porfirini i njihovi Zn(II) analozi s alkilnim
lancima različitih duljina (7-17 ugljikovih atoma). Zn(II)-porfirin s alkilnim lancem od 13 Catoma pokazao je najveću citotoksičnost i selektivnost prema staničnoj liniji melanoma
nakon osvjetljavanja narančastom svjetlošću. Drugi dio uključivao je sintezu amfifilnih Noksidiranih pirid-3-ilporfirina, gdje su se porfirini s lancem od 13 i 17 C atoma pokazali
obećavajućima protiv stanične linije melanoma, smanjujući utjecaj pigmenta melanina. U
posljednjem dijelu amfifilni (piridinij-3-il)porfirini kelirani su s 68Ga(III) i natGa(III) kako bi
se dobili PET/PDT agensi, a njihova distribucija analizirana je PET-CT skeniranjem.
Utvrđeno je da ravnoteža hidrofilnih i lipofilnih dijelova ne samo da utječe na citotoksičnost
i selektivnost in vitro, već pokazuje i različitu biodistribuciju in vivo. Ovaj rad i saznanja
dobivena na temelju rezultata o A3B piridilporfirinima dat će nam dublji uvid o utjecaju
amfifilnosti molekule i dovesti nas do daljnjeg razvoja "idealnog fotosenzibilizatora" za
upotrebu u PDT-u
Teorijske simulacije kvazičestičnih spektara u dopiranom grafenu
No full textThis thesis covers several aspects of the electronic and electromagnetic properties of doped
graphene; peculiar properties of the 2D plasmon, strong quasi-particle interactions with these
plasmons and finally the possibility of transforming these plasmons into radiative modes. The
thesis is imbued with comparisons with available experiments and offers a solution to the longstanding problem of plasmon emission prosess seen in ARPES experiments.
A graphene is a 2D single-layer hexagon crystal, with two atoms in the unit cell. The
electrostatic doping fills its π∗ / π bands with the electrons / holes, enabling the well known
intraband Dirac plasmon. When the graphene is doped with alkali metals, its band structure
introduces a metallic σ band, which profusely fills the graphene π∗ band with the electrons.
In this way, two 2D electron gases interplay, which makes the plasmonic properties of doped
graphene even more interesting.
Moreover, the simulated spectra of electronic excitations in the graphene intercalated with
potassium [KC8 (2x2)] and caesium [CsC8 (2x2)] atoms exhibit very intensive Dirac plasmon,
which dominates the IR frequency range of the electron excitations spectra. On the other hand,
the acoustic plasmon also dominates the IR frequency range of the KC8 spectra, unlike in the
CsC8. More precisely, the acoustic plasmon does not appear at all in the CsC8 spectra of, and a
mechanism responsible for its disappearance is based on the interlayer interband screening due
to the electronic excitations.
In addition to plasmons in the infrared region, we shall also study interband plasmons in
the ultraviolet region, in various graphene intercalates such as KC8, CsC8, LiC2 and LiC6. A
comparative analysis with electrostatically doped graphene will also be done. Furthermore,
when these systems are electrostatically doped with electrons / holes, their spectra of electronic
excitations change drastically as a function of doping.
Here we also study the intercation between electrons / holes in π / π ∗ bands in electrostatically or chemically doped graphene (KC8) with the electronic excitations (focused to the Dirac
plasmon). The electron / hole spectra were calculated using a newly developed G0W0 approximation, which corrects the DFT Green’s function in terms of the induced correlation self energy, which simulates ARPES measurements. In this thesis, we shall see how the electron doping of the graphene π∗ band affects the renormalization of Fermi and Dirac group velocites, kinks at
the Fermi energy and widths of the hole decays in the π and π∗ bands. Finally, we shall see
that both deformation and abrupt increase in the decay width of the π band just below the Dirac
point is due to the Dirac plasmon emission. These theoretical observations will be compared
with the results of other theoretical and experimental studies.
In this thesis, we also investigate the electromagnetic properties of doped graphene and the
intensities of IR active plasmons in graphene nanoribbons. Plasmons in the doped graphene are
non-radiative (evanescent) modes that cannot be excited directly by photons, but only indirectly,
e.g. by scattering of the IR photon stream. In this way the photons scattered in the near-field
region couple to the plasmons and excite them. Yet another way to excite plasmons is to slice
the graphene into nanoribbons that support dipole-active plasmons. In the end, we shall study
the IR active plasmonic resonances in the 1D array of the KC8 nanoribbons, and compare them
with experimental measurements. Also, the synthesis of the KC8 nanoribbons will be discussed.Ova doktorska disertacija istražduje nekoliko aspekata elektronskih i elektromagnetskih svojstava dopiranog grafena; neobicna svojstva 2D plazmona, jake kvazičestične interakcije sa plazmonima te konačno mogućnost transformiranja plazmona u radijativne modove. Disertacija je prožeta usporedbama teorijskih rezultata s dostupnim eksperimentima, te nudi rješenje dugogodišnjeg problema razumijevanja procesa plazmonske emisije u ARPES eksperimentima.
Grafen je 2D jednoslojni heksagonski kristal, koji sadrži dva atoma u jediničnoj ćeliji. Elektrostatsko dopiranje puni njegove π∗ / π vrpce elektronima / šupljinama, omogucavajući dobro znani unutar vrpcani Diracov plazmon. Pri dopiranju grafena alkalijskim metalima, u vrpčastu strukturu ulazi metalna σ vrpca, koja obilato puni grafenovu π∗ vrpcu elektronima. Time počinje međuigra dva 2D elektronska plina, koja čini plazmonska svojstva dopiranog grafena još zanimljivijima.
Štoviše, teorijske simulacije spektara elektronskih pobudenja u grafenu interkaliranog kalijevim [KC8 (2x2)] i cezijevim [CsC8 (2x2)] atomima pokazuju Diracov plazmon visokog intenziteta, koji dominira IR frekvencijskim podrucjem spektara elektronskih pobuđenja. S druge strane, akustični plazmon također dominira IR frekvencijskim podrucjem KC ˇ 8 spektara , ali to nije slučaj i za CsC8. Tocnije, akustični plazmon se uopće ne pojavljuje u CsC8 spektrima, a
mehanizam koji je zaslužan za njegov nestanak se bazira na meduvrpčanom zasjenjenju između razlicitih slojeva radi elektronskih pobuđenja.
Osim plazmona u IR frekvencijskom podrucju, u ovoj disertaciji ćemo se također baviti i međuvrpčanim plazmonima u ˇ UV području. Proučavat će se grafeni interkalirani alkalijskim atomima, poput KC8, CsC8, LiC2 i LiC6, uz usporedbu sa rezultatima za elektrostatski dopirani grafen. Štoviše, pri elektrostatskom dopiranju sustava elektronima / šupljinama, njihovi spektri elektronskih pobudenja se drastično mijenjaju kao funkcija dopiranja.
Proucavat će se i interakcija šupljina / elektrona u ´ π / π∗ vrpcama elektrostatski ili kemijski dopiranog grafena (KC8) sa elektronskim pobudenja (s fokusom na Diracov plazmon). Spektri elektrona / šupljina su izracunati koristeći novorazvijenu G ´ 0W0 aproksimaciju, koja popravlja DFT Greenovu funkciju koristeci induciranu korelacijsku ´ self energiju, a oni su zapravo simulacija ARPES (Angle-resolved photoemission spectroscopy) mjerenja. U ovoj disertaciji pokazat
ću kako dopiranje grafenske ´ π ∗ vrpce utjece na renormalizaciju Fermijevih i Diracovih grupnih brzina, kinkove na Fermijevoj energiji, te širine raspada šupljina u π i π∗ vrpcama. Na koncu, vidjet ćemo i da se deformacija i nagli porast širine raspada ´ π vrpce odmah ispod Diracove točke pojavljuje radi emisije Diracovog plazmona. Teorijska opažanja će se također usporediti sa rezultatima drugih teorijskih i eksperimentalnih istraživanja.
U ovoj disertaciji istraživana su i elektromagnetska svojstva dopiranog grafena, kao i intenziteti IR aktivnih plazmona u grafenskim nanovrpcama. Plazmoni u dopiranom grafenu su neradijativni modovi, koji se ne mogu pobuditi direktno fotonima vec samo indirektno, npr. raspršenjem IR fotonskog snopa. Tako se fotoni raspršeni u near-field području vežu na plazmone, te ih pobuđuju. Drugi način da se pobude plazmoni je da se grafen nareže na nanovrpce koje podržavaju dipolno-aktivne plazmone. Naposljetku, analizirati ćemo ´ IR aktivne plazmone u 1D nizu nanovrpci izrezanih iz KC8, te ih usporediti sa eksperimentalnim mjerenjima, a baviti ćemo se i sintezom KC ´ 8 nanovrpci
Invazivnost stranih slatkovodnih riba i učinak prenesenih vrsta na zajednice riba krških rijeka
No full textIntroduced and translocated species are significant threats to biodiversity due to their potential impacts, including competition for resources, predation, hybridization, disease transmission, and habitat degradation. Despite their importance, the effects of these species under current and future climate scenarios, particularly in sensitive karst ecosystems such as the Adriatic basin’s Lika River, remain insufficiently studied. This research aimed to assess the risks posed by non-native and translocated fish species in Croatia under present and projected climatic conditions, focusing on identifying the highest-risk species introduced into the Adriatic basin. Additional objectives included analyzing the ichthyofaunal composition of the Lika River basin, examining the distribution of native and non-native species, and investigating the biology and ecology of the most high-risk translocated fish species. Risk screening was performed using the Aquatic Species Invasiveness Screening Kit (AS-ISK), following standard protocols. Fish sampling, conducted via electrofishing, took place between May 2021 and July 2022 across five rivers, encompassing both the Danube River basin (Sava River) and the Adriatic River basin (Lika, Jadova, Bogdanica, and Novčica rivers). During each sampling event, physico-chemical and habitat characteristics were recorded. Fish specimens were measured for total length, standard length, and weight. Additionally, Squalius cephalus specimens were sacrificed for further biological analyses. For the entire sampled community, Fulton’s condition factor and the length-weight relationship were calculated, while for S. cephalus, additional metrics such as the gonadosomatic index, hepatosomatic index, digestive tract fullness index, and vacuity coefficient were assessed. Multivariate and univariate statistical analyses, including Canonical Correspondence Analysis (CCA), Kruskal-Wallis tests, Dunn’s post-hoc tests, ANOVA, Tukey’s post-hoc tests, and generalized linear models, were performed using CANOCO and R software packages to analyse environmental and biological data. The study identified 54 high-risk and 22 medium-risk non-native fish species under current climate conditions, with similar results projected under future climate scenarios. Squalius cephalus was classified as a high-risk translocated species. In the Lika River basin, eight translocated species from the Danube basin were recorded, including S. cephalus, along with one invasive species (Lepomis gibbosus) and one native endemic stygophilous species (Delminichthys jadovensis). Notably, S. cephalus was abundant in the translocated habitats of the Lika, Jadova, and Bogdanica rivers but was absent from the Novčica River. The species exhibited successful adaptation in new environment, with the first spawning phase observed in March, when water temperatures ranged from 9.8°C to 12.5°C. The detection of intestinal parasites in both native and translocated populations is noteworthy, with Neoechinorhynchus sp. Being recorded for the first time in the region and in Croatia. The findings indicate that translocated species, particularly S. cephalus, compete with native fish community and may serve as vectors for pathogens, posing a threat to endemic populations. These results underscore the need for informed management strategies to mitigate the risks associated with non-native fish introductions in Croatia.Unesene i prenesene vrste jedna su od glavnih prijetnji bioraznolikosti i zavičajnim vrstama, zbog mogućih negativnih utjecaja poput natjecanja za hranu, predatorstva, hibridizacije, prijenosa bolesti i degradacije staništa. Hrvatska ima jednu od najbogatijih zajednica zavičajne slatkovodne ihtiofaune u Europi, ali istovremeno ima značajan broj unesenih ribljih vrsta, kao I vrsta koje se nalaze vrlo blizu njenih teritorijalnih granica, o čijem riziku unosa nema dovoljno podataka. Također, mnoge riblje vrste u Hrvatskoj prenesene su iz jedne biogeografske regije u drugu, u područja gdje one ne bi mogle prirodno dospjeti, primjerice prijenos riba iz dunavskog u jadranski slijev. O riziku njihovog unosa u sadašnjim i budućim klimatskim uvjetima te o njihovom utjecaju na osjetljive krške ekosustave jadranskog slijeva, kao što je područje rijeke Like, i na zavičajnu riblju populaciju, još uvijek nema dovoljno istraživanja.
Prvi cilj ovog istraživanja bio je procijeniti rizik unosa stranih i prenesenih vrsta riba u sadašnjim i budućim klimatskim uvjetima na području Hrvatske. Posebna pažnja posvećena je prenesenim vrstama kako bi se identificirala najrizičnija riblja vrsta prenesena u jadranski slijev. Daljnji ciljevi istraživanja uključivali su utvrđivanje sastava ihtiofaune u slijevu rijeke Like, analizu distribucije stranih i zavičajnih vrsta, te istraživanje biologije i ekologije najrizičnije prenesene riblje vrste I njenog utjecaja na zavičajnu ihtiofaunu.
U uvodu je opisan utjecaj stranih i prenesenih vrsta na zavičajne ekosustave. Osim toga, naveden je sastav ihtiofaune slijeva rijeke Like prema podacima iz dosadašnjih istraživanja, kao i istraživanja identifikacije rizika stranih i prenesenih vrsta na području Balkanskog poluotoka.
Prvi dio poglavlja pregled literature odnosi se na identifikaciju rizika, odnosno opisano kako je razvijen alat za procjenu invazivnosti akvatičnih vrsta (AS-ISK), zatim od kojih komponenti se sastoji te za koje područja procjene rizika je dosada korišten. Uz to, navedeni su podaci o istraživanjima koja se odnose na identifikaciju rizika. Drugi dio poglavlja vezan je za prijenos ihtiofaune u nova biogeografska područja te kakvu one prijetnju predstavljaju zavičajnoj ihtiofauni u osjetljivim ekosustavima kao što su krški. Također, opisan je povijesni i sadašnji sastav ihtiofanue na području Ličko-senjske županije te su opisane invazivne karakteristike dvije najdominantnije prenesene vrste, klena Squalius cephalus i bodorke Rutilus rutilus. Treći dio poglavlja sastoji se od opisa ekoloških značajki S. cephalus u izvornom i unesenom staništu. Opisana je distribucija S. cephalus i načini njegova unosa, prikazane su informacije o staništu, prehrani, reproduktivnim i drugim ekološkim značajkama.
U poglavlju Materijal i metode opisana je metodologija za identifikaciju rizika, ribljih zajednica, biologije i ekologije S. cephalus uz opis područja i razdoblja istraživanja. Istraživanje je provedeno od svibnja 2021. do srpnja 2022. godine. Uzorkovanje ihtiofaune elektroribolovom obavljeno je na jednoj lokaciji u dunavskom slijevu (Rijeka Sava) i četiri lokacije u jadranskom slijevu, u slijevu rijeke Like (Lika, Jadova, Bogdanica i Novčica). Prilikom svakog uzorkovanja zabilježene su osnovne fizikalno-kemijske karakteristike vode i staništa. Svakoj jedinki izmjerena je totalna i standardna dužina te izmjerena propadajuća masa. Nakon mjerenja, svaka jedinka S. cephalus bila je secirana te je zabilježena eviscerirana masa, mase gonada i jetre, kao i masa sadržaja crijeva. Na osnovu dobivenih vrijednosti izračunat je Fultonov faktor kondicije, dužinsko maseni odnosi, gonadosomatski i hepatosomatski indeks, zatim indeks punoće probavila i indeks praznog probavila. Ukoliko su prilikom sekcije pronađeni paraziti u crijevima jedinki S. cephalus, fiksirani su u 96% etanolu za potrebe molekularne identifikacije. Analiza kanoničke korespondencije i linearna analiza redundancije koristile su se za definiranje povezanosti parametara okoliša sa zajednicama riba iz zavičajnog i unesenog područja, kao i rasprostranjenosti svih vrsta. Za utvrđivanje statistički značajnih razlika, Fultonov faktor kondicije i hepatosomatski indeks između lokacija, korišten je Kruskal-Wallis i Dunn’s post-hoc test kod normalno distribuiranih podataka, a ANOVA i Tukey post-hoc test kad su podaci bili normalne distribucije. Razlike u vrijednostima gonadosomatskog indeksa između lokacija uvrđene su uz pomoć generaliziranog linearnog modela kod normalne distribucije podataka, dok je Kruskal-Wallis i Dunn’s post-hoc test korištene kada podaci nisu bile normalne distribucije. Popis vrsta za procjenu rizika napravljen je na osnovu podataka iz objavljene znanstvene literature, a horizon vrsta odabrane su pomoću CABI programa. Identifikacija potencijalno visokorizičnih vrsta napravljena je pomoću alata za procjenu invazivnosti akvatičnih vrsta (AS-ISK). Granična vrijednost za BRA i BRA + CCA pomoću kojeg su se razlikovale srednje i visoke razine rizika utvrđena je metodom operativnih karakteristika primatelja (ROC). Permutacijskom dvofaktorijelnom ANOVA analizom utvrdila se razlika u razinama pouzdanosti između područja procjene rizika i BRA i BRA + CCA). Statistička obrada podataka provedena je pomoću progamskih paketa CANOCO I R.
Dobiveni Rezultati pokazuju da su sadašnjim klimatskim uvjetima ukupno 54 vrste koje su klasificirane kao visokorizične i 22 klasificirane kao srednje rizične prijetnja autohtonoj ihtiofauni Hrvatske, dok su u budućim klimatskim uvjetima također 54 klasificirane kao visoko rizične vrste te 21 kao srednje rizična i 1 kao nisko rizična. Strane vrste s najvećim indeksom invazivnosti u sadašnjim klimatskim uvjetima su Ameiurus nebulosus, Neogobius melanostomus, Pseudorasbora parva i Silurus glanis, dok su u budućim klimatskim uvjetima to vrste poput Gambusia affinis, Ictalurus punctatus i Mylopharyngodon piceus. Od ukupno 20 prenesenih vrsta iz dunavskog u jadranski slijev, njih 14 klasificirane su kao visoko rizične od kojih je najznačajnije istaknuti Cyprinus carpio, Esox lucius, Perca fluviatilis, Rutilus rutilus, Salmo trutta, Sander lucioperca, Scardinius erythrophthalmus, Silurus glanis, S. cephalus. Rijeku Liku, Bogdanicu, Jadovu i Novčicu naseljava 8 vrsta premještenih iz dunavskog sliva, a to su: Alburnus alburnus, Carassius carassius, Esox lucius, Perca fluviatilis, Rutilus rutilus, Scardinius erythrophthalmus, Squalius cephalus, Tinca tinca, te jedna invazivna vrsta kao što je Lepomis gibbosus. Tijekom istraživanja zabilježena je samo jedna zavičajna vrsta Delminichthys jadovensis, čije je stanište rijeka Jadova. U rijeci Savi zabilježeno 13 zavičajnih vrsta, od kojih je S. cephalus bio među najzastupljenijima, i 3 strane vrste poput P. parva, L. gibbosus i Carassius gibelio. U prenesenom području S. cephalus je bio najbrojniji u rijeci Lici, Jadovi i Bogdanici dok u rijeci Novčici nije bio zabilježen. Osim uspješne prilagodbe, utvrđeno je da se S. cephalus mrijesti u prenesenom staništu. Prva faza mrijesta S. cephalus iz rijeke Save, Like i Bogdanice bila je u ožujku, kada je temperature vode bila između 9,8°C i 12,5°C. Vrlo značajan je nalaz crijevnih patogena (Acanthocephalus sp) kod S. cephalus u zavičajnom području (Rijeka Sava) i u unesenom području (slijev rijeke Like) koji je postao vrlo rasprostranjen na istraživanom području. Još značajniji nalaz je prisutnost parazita probavnog trakta Neoechinorhynchus sp. Na jedinkama klena iz rijeke Like, što predstavlja prvi nalaz ovog roda u cijelom slijevu kao i prvi nalaz kod klena u Hrvatskoj. Rezultatima ovog istraživanja utvrdilo se da su prenesene vrste, a osobito S. cephalus, konkurenti za stanište zavičajnoj zajednici stigofilnih riba te mogu biti potencijalni prijenosnici patogena što bi se moglo vrlo nepovoljno odraziti na cjelokupnu preostalu endemsku zajednicu. Dodatno, istraživanje ima primjenu za buduću strategiju upravljanja stranim vrstama u Hrvatskoj
ORGANSKA ONEČIŠĆIVALA OD RASTUĆEGA ZNAČAJA U KRŠKIM PODZEMNIM VODAMA U HRVATSKOJ
No full textNapredak analitičkih metoda i instrumenata omogućio je otkrivanje organskih onečišćivala od rastućega značaja (OORZ) u površinskim i podzemnih vodama u koncentracijama reda veličine ng/L do μg/L, a čija je prisutnost u okolišu rezultat kontinuiranoga, svakodnevnoga ispuštanja diljem svijeta. Istraživanje pojavnosti i ponašanja OORZ-a u krškim vodonosnicima je u začecima, što je razlog trenutnog nedostatka političkih mjera i zakonodavne kontrole za ove spojeve u podzemnim vodama. Vodonosnici dinarskog krša opskrbljuju pitkom vodom gotovo
polovicu teritorija Hrvatske, a odlikuje ih heterogenost i anizotropnost strukturnih i hidrauličkih značajki, intenzivna okršenost i znatna pukotinsko-kavernozna poroznost. Ove značajke rezultiraju brzim tokovima podzemne vode i izdašnim krškim izvorima, ali istovremeno čine krške vodonosnike izrazito ranjivima na onečišćenje te njihovo istraživanje složenim i izazovnim. Znanstveni radovi objavljeni kao dio ove doktorske disertacije po prvi puta u
Hrvatskoj identificiraju i kvantificiraju OORZ-ove u krškim vodonosnicima na regionalnoj (17
krških izvora i jedno jezero) i lokalnoj (izvori Jadro i Žrnovnica, bušotina Gizdavac i rijeka Cetina) razini. U dvije sveobuhvatne kampanje analizirano je 740 OORZ-a, od čega je utvrđena pojavnost 65 spojeva na regionalnoj razini, među kojima su najčešće detektirani farmaceutici
(n=26) i poljoprivredni spojevi (n=26). Industrijski spojevi i umjetna zaslađivala imala su
najviše koncentracije do 90 ng/L (TPPA) i 440 ng/L (sukraloza). Tijekom sedam kampanja uzorkovanja na lokalnoj razini slijeva izvora Jadra i Žrnovnice, identificirana su 22 OORZ-a u
koncentracijama koje su se kretale od 0.3 ng/L (opioidni analgetik tramadol) do 372 ng/L
(industrijski spoj 1H-benzotriazol). Repelent DEET bio je najčešće detektiran spoj prosječne koncentracije od 50 ng/L utvrđene u površinskoj vodi rijeke Cetine, izvorima i podzemnoj vodi.
Niže koncentracije i manja učestalost detekcije OORZ-a u hrvatskom kršu, za razliku od drugih krških područja, sugeriraju značajno razrjeđenje koje se pripisuje velikim protocima izvora “klasičnog krša” i relativno niskom intenzitetu poljoprivrednih i industrijskih aktivnosti u istraživanom području. Maksimalne koncentracije OORZ-a u izvorima Jadro i Žrnovnica
uočene su nakon jesenskih kiša, dok tijekom najviših protoka uslijed razrjeđenja nije zabilježena pojavnost spojeva iznad granica detekcije (LOD). Suprotno izvorima, u podzemnoj
vodi iz duboke bušotine Gizdavac, najveća ukupna koncentracija OORZ-a utvrđena je pri
uvjetima malih protoka što naglašava značajnu ranjivost krškog vodonosnika. Uz uvid u dinamiku krškog sustava, analiza hidrokemijskih značajki pokazala se korisnom za bolje razumijevanje funkcioniranja i ranjivosti hidrogeoloških sustava na OORZ-ove. Oštri skokovi uočeni na kemografovima izvora Jadra i Žrnovnice dokaz su značajne okršenosti i inherentne
ranjivosti sustava. Zastupljenost ponora, razvijene mreže krških kanala i pukotina mogu
pospješiti transport OORZ-a. Utvrđena je snažna, statistički značajna pozitivna korelacija između metformina i iona NO3
-, kao i koncentracije OORZ-a, broja detektiranih spojeva i iona
NO3
- u rijeci Cetini, što ukazuje na njihovo zajedničko porijeklo, vjerojatno otpadnu vodu.
Pojavnost postojanih OORZ-a u izvorima i podzemnoj vodi pri uvjetima niskih voda i pozitivna
statistički značajna korelacija DEET-a s Ca2+ ionom, ukazuje na potencijalno skladištenje postojanih OORZ-a u pukotinsko-poroznoj epikrškoj zoni vodonosnika. Uočena sezonalnost i
sveprisutnost u slijevu indikatora onečišćenja otpadnom vodom, spojeva DEET i 1Hbenzotriazola, ukazuje na ograničenu atenuaciju postojanih i mobilnih spojeva unutar krškog vodonosnika. Kako na regionalnoj, tako i na lokalnoj razini, većina otkrivenih spojeva ocijenjena je kao potencijalno postojana, mobilna i toksična ili kao vrlo postojana i vrlo
mobilna, ukazujući na njihov potencijalno negativan utjecaj na ekosustav podzemnih voda. Analizom utjecaja na ljudsko zdravlje utvrđeno je kako izmjerene koncentracije OORZ-a u
ng/L u krškim izvorima koji se koriste u vodoopskrbi, trenutno ne predstavljaju značajan rizik za zdravu populaciju, no preporuka je da se budućim istraživanja analiziraju potencijalni učinci
dugotrajne izloženosti koktelu različitih OORZ-a. Važno je uspostaviti protokole redovitog praćenja OORZ-a koji su prioritizirani ovom disertacijom na temelju analize njihove postojanosti, bioakumulativnosti, mobilnosti i toksičnosti, uz razmatranje mogućnosti provedbe Dobrovoljnog popisa praćenja OORZ-a u podzemnim vodama, prilagođenog karakteristikama dinarskog krša. Radi utvrđivanja potencijalnih pozadinskih koncentracija OORZ-a i njihovog
ponašanja pri različitim hidrološkim uvjetima, fokus budućih istraživanja treba usmjeriti na analize događaja na razini pojedinih sljevova. Za slijev izvora Jadra i Žrnovnice predlaže se praćenje spojeva DEET-a, 1H-benzotriazola i metformina. Također, ističe se prednost usporedne analize hidrokemijskih markera i OORZ-a kao novih trasera koji će rasvijetliti zamršeno međudjelovanje čimbenika koji utječu na transport unutar krških vodonosnika i uvjetuju kemiju podzemnih voda podložnih različitim antropogenim pritiscima. Takva
istraživanja pružit će uvide ključne za smanjenje rizika, posebice u svjetlu očekivanog porasta opterećenja onečišćenjem u nadolazećim godinama i utjecaja klimatskih promjena na količine vode.Owing to considerable advancement in analytical techniques and instrumentation, emerging
organic contaminants (EOCs) are being detected in both surface water and groundwater at
concentrations ranging from ng/L to μg/L, where they have been introduced by ongoing, global
daily emissions. Research on the occurrence and behaviour of EOCs in karst aquifers is in its early stages, leading to a dearth of policy measures and legislative controls for these compounds in groundwater. The Dinaric karst aquifers, which provide drinking water to nearly half of Croatia's territory, exhibit heterogeneous, anisotropic structural and hydraulic characteristics, intense karstification, and high fracture-cavernous porosity. These features result in rapid
groundwater flow and large karst springs, yet they also render the aquifers highly vulnerable to contamination and their investigation intricate and challenging. The scientific papers published
as part of this PhD thesis were the first to identify and quantify EOCs within Croatian karst
aquifers at regional (17 karst springs and 1 karst lake) and local (4 locations within Jadro and Žrnovnica catchment) scales. Through two comprehensive campaigns encompassing analysis of 740 EOCs, 65 compounds were detected at the regional level, with pharmaceuticals (n=26)
and agrochemicals (n=26) being predominant. Industrials and artificial sweeteners exhibited
the highest concentrations up to 90 and 440 ng/L, respectively. At local scale, 22 EOCs were identified in the karst catchment of Jadro and Žrnovnica springs during seven sampling campaigns, with concentrations reaching up to 372 ng/L. The comparatively lower
concentrations and detection frequency of EOCs in the Croatian karst, as opposed to other karst
regions, suggest significant dilution attributed to substantial discharge of “classical karst” springs and relatively low intensity of agricultural and industrial activities in the area. At both
regional and local scales, the majority of compounds were assessed as potentially persistent,
mobile and toxic or very persistent and very mobile, unraveling their potential negative impact
on (ground)water ecosystem. While current concentrations of EOCs in ng/L in karst drinking
water are not expected to pose a significant risk to healthy populations, future research should
analyse the potential effects of long-term exposure to EOCs mixtures, particularly for
vulnerable or at-risk groups. The importance of establishing regular monitoring protocols for EOCs prioritized with this thesis is underscored, with due consideration given to the
implementation of a Voluntary Groundwater Watch List tailored to Dinaric karst
characteristics. Future in-depth event analysis at catchment levels is recommended, to elucidate
potential background EOCs levels and their behaviour under varying hydrological conditions.
Such research will offer crucial insights for risk mitigation, in light of the expected increase in
contamination mass loads in the coming years and the ongoing impact of climate changes on water quantities
Sklopovi velike brzine rada za očitavanje CMOS detektora nabijenih čestica
No full textThe planned MALTA3 DMAPS designed in the standard TowerJazz 180 nm imaging process
will implement the numerous process modifications, as well as front-end changes in order to
boost the charge collection efficiency after the targeted fluence of 1x1015 1 MeV neq/cm2 . The effectiveness of these changes have been demonstrated with recent measurements of the full size MALTA2 chip. With the original MALTA concept being fully asynchronous, a small-scale MiniMALTA demonstrator chip has been developed with the intention of bridging the gap between the asynchronous pixel matrix, and the synchronous DAQ. This readout architecture will serve as a baseline for MALTA3, with focus on improved timing performance. The synchronization memory has been upgraded to allow clock speeds of up to 1.28 GHz, with the goal of achieving a sub-nanosecond on-chip timing resolution. The subsequent digital readout chain has been modified and will be discussed in the context of the overall sensor architecture.Planirani MALTA3 DMAPS, dizajniran u standardnom TowerJazz 180 nm procesu za snimanje, implementirat će brojne modifikacije procesa, kao i promjene u prednjem dijelu kako bi se poboljšala učinkovitost prikupljanja naboja nakon ciljanog fluensa od 1x1015 1 MeV neq/cm2. Učinkovitost tih promjena potvrđena je nedavnim mjerenjima čipa pune veličine MALTA2. Budući da je izvorni koncept MALTA potpuno asinhron, razvijen je demonstracijski čip malih dimenzija pod nazivom MiniMALTA s namjerom da se premosti jaz između asinhrone matrice piksela i sinkrone akvizicije podataka (DAQ). Ova arhitektura očitavanja služit će kao osnovna za MALTA3, s fokusom na poboljšanje vremenskih performansi. Sinkronizacijska memorija je nadograđena kako bi omogućila taktne frekvencije do 1,28 GHz, s ciljem postizanja vremenske rezolucije ispod jedne nanosekunde na čipu. Naknadni digitalni lanac za očitavanje je modificiran i bit će raspravljen u kontekstu cjelokupne arhitekture senzora
Assessment of microRNAs expression in maternal and neonatal pairs in association with cigarette smoke exposure
No full textUvod: Mehanizam štetnog djelovanja pušenja uključuje promjene miRNA koje reguliraju gensku ekspresiju. Cilj istraživanja bio je ispitati povezanost ekspresije odabranih miRNA, koncentracije toksičnih i esencijalnih metala te biokemijskih parametara u ovisnosti o pušenju majke u svim uzorcima fetoplacentalne jedinice.
Materijali i metode: Presječno retrospektivno istraživanje uključivalo je 72 para majka-novorođenče (35 pušačica i 37 nepušačica) regrutirana tijekom 2018. i 2019. godine. Ekspresije ciljnih miRNA (miR1537, miR190B, miR16-1, miR21 i miR146A) određene su RT-PCR-om. Koncentracije esencijalnih (Fe, Cu i Zn) i toksičnih metala (Cd i Pb) izmjerene su ICP-MS-om. Biokemijski parametri (glukoza, urati, trigliceridi, ukupni kolesterol, LDL-C i HDL-C) analizirani su na biokemijskom analizatoru enzimatskim metodama, a CRP metodom imunoturbidimetrije. Programski paket Statistica korišten je za statističku obradu podataka (P<0,050).
Rezultati: Pušačice vs. nepušačice imaju višu ekspresiju miRNA16-1 u majčinoj plazmi i miRNA146A u plazmi pupkovine, a nižu ekspresiju miRNA21 u posteljici te niže koncentracije Fe u serumu i urata u plazmi. Koncentracije Cd u pušačica povećane su u svim ispitivanim uzorcima fetoplacentalne jedinice, dok su koncentracije Pb povećane samo u majčinoj krv i posteljici.
Zaključak: Istraživanje je pokazalo da toksične tvari kojima smo izloženi pušenjem mogu imati utjecaja na molekularne regulacijske mehanizme i time utjecati na zdravlje majke i djeteta.Introduction: The smokings' harmful effects mechanism involves miRNA changes which regulate gene expression. The study aims to investigate impact of maternal smoking on candidate miRNAs expression, essential and toxice metal levels, and biochemical parameters in feto-placental unit.
Materials and methods: Cross-sectional retrospective study included 72 mother-newborn pairs (35 smokers and 37 non-smokers) recruited during 2018/2019. Candidate miRNAs (miR1537, miR190B, miR16-1, miR21, and miR146A) were determined by RT-PCR. Essential (Fe, Cu, and Zn) and toxic metals (Cd and Pb) were measured by ICP-MS. Biochemical parameters (glucose, urates, triglycerides, total cholesterol, LDL-C and HDL-C) were analyzed by biochemical analyzer using enzymatic methods, and CRP by immunoturbidimetry. Statistical analysis was done by Statistica software (P<0.050).
Results: Smokers vs. non-smokers have higher expression of miR-16-1 in maternal and miR-146A in cord plasma, and lower expression of miR-21 in placenta, as well as lower concentration of serum Fe and plasma urate. Cd concentrations in smokers were higher in all compartments of feto-placental unit, while Pb concentrations were higher only in maternal blood and placenta.
Conclusion: Research showed that toxic substances to which we are exposed through smoking can have an impact on molecular regulatory mechanisms and thus affect health of the mother and child