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Urban Heat Load in a Small Mediterranean City in Recent, Extreme and Future Climate Conditions—A Case Study for the City of Dubrovnik
No full textThis article examines the urban heat load (UHL) of Dubrovnik, a small Mediterranean city located in the complex terrain of the eastern Adriatic coast. In the study, the characteristics of the UHL are investigated in three special scenarios that mimic the different climate conditions: the recent climate (1981–2010), the hypothetical extreme climate (consisting of the 10 years with the hottest summers in the period 1961–2021) and the future climate (2041–2070) according to the RCP4.5 scenario. The UHL is quantified in terms of climate indices with fixed thresholds, defined as the annual number of days on which the daily minimum or maximum temperature exceeds certain thresholds. The analysis was carried out using the microscale urban climate model MUKLIMO_3. In addition, the potential benefits of certain measures to reduce UHL were investigated. In relation to the recent climate, the results show an increase in the amplitude of UHL under extreme and future climate conditions, with the UHL being strongest under the projected future climate conditions. In all three scenarios, the UHL is the highest in the built-up parts of the city. However, a strong increase in UHL is obtained in the green parts of the domain indicating a possible reduction in the cooling capacity of green areas under warmer climate conditions. Applied land use/land cover (LULC) changes of the model area, which include changes in the albedo of roofs, the proportion of low vegetation, impervious surfaces and built-up areas, have some influence on the reduction of UHL, but their effect is quite weak and mostly local. The greatest effect on reducing diurnal UHL is achieved by changing albedo, while the most effective reduction in nocturnal UHL is achieved by a combination of changes in albedo, the proportion of low vegetation, impervious surfaces and built-up areas. Considering the relatively weak cooling effect of the LULC modifications and the potential reduction in vegetation efficiency under warmer climate conditions as well as the expected increase in heatwaves, it is likely that Dubrovnik will suffer from extremely high UHL in the future
DEVELOPMENT OF AN ELECTROCHEMICAL METHOD FOR MONITORING POLYSULFIDES (Sx2-) IN MARINE EUXINIC ENVIRONMENT
No full textDirektno analitičko određivanje polisulfida (Sx2-) u vodenim otopinama predstavlja izazov zbog niskih konstanti termodinamičke stabilnosti Sx2-. S ciljem razvoja i primjene direktne metode za određivanje i karakterizaciju Sx2-, istraživano je njihovo elektrokemijsko ponašanje na živinoj (Hg) elektrodi. Morski euksinski okoliš Rogozničkoga jezera – Zmajeva oka (RJ) izabran je kao model za ispitivanje elektroanalitičke metode (EM), difercijalno pulsne voltametrije (DPV) za direktno određivanje polisulfida u prirodnim uvjetima. Za praćenje reduciranih sumpornih specija (RSS), odnosno Sx2- uz DPV, korištene su i ciklička voltametrija (CV) i stepenasta DC voltametrija/polarografija (SDC), ali i druge analitičke metode: UV/Vis spektrofotometrija za dodatno određivanje Sx2-, te mikroskopija atomskih sila (eng. atomic forced microscopy, AFM) i dinamičko raspršenje svjetlosti (eng. dynamic light scattering, DLS) za praćenje promjene svojstava RSS. AFM-om je praćena promjena morfologije stanica fototrofnih sumpornih bakterija kao izvora elementarnog S pri različitim okolišnim i eksperimentalnim uvjetima, dok je s DLS praćena promjena hidrodinamičkog radijusa elementarnog S u različitim uvjetima razrjeđenja. DPV metodom određeni su Sx2- u modelnim otopinama, te u RJ s najvećim koncentracijama u uzorcima ispod kemokline. Praćenjem sezonske dinamike Sx2- pokazano je kako njihova prisutnost i koncentracija ovise o fizikalno – kemijskim i mikrobiološkim čimbenicima. Najveće koncentracije, do 89 μM polisulfidnog S0, određene su tijekom ljeta za vrijeme izraženije raslojenosti vodenog stupca i intenzivnije mikrobiološke aktivnosti kada su dominirale ljubičaste sumporne bakterije (eng. purple sulfur bacteria, PSB), dok tijekom slabije raslojenosti i pojave holomiksije, Sx2- nisu detektirani.The direct analytical determination of polysulfide (Sx2-) in seawater solutions is a challenge due to the low thermodynamic stability constants of Sx2-. To develop and apply a direct method for determining and characterizing Sx2-, its electrochemical behavior was investigated at a mercury (Hg) electrode. The marine euxinic environment of Lake Rogoznica – Zmajevo oko (RL) was chosen as a model for testing the electroanalytical method (EM), differential pulse voltammetry (DPV) for the direct determination of polysulfides under natural conditions. In addition to DPV, cyclic voltammetry (CV) and sampled DC voltammetry/polarography (SDC) were also used to monitor reduced sulfur species (RSS), i.e. Sx2-, as well as other analytical methods: UV/Vis spectrophotometry for additional determination of Sx2- and atomic force microscopy (AFM) and dynamic light scattering (DLS) to monitor changes in RSS properties. The change in cell morphology of phototrophic sulfur bacteria as a source of elemental S under different environmental and experimental conditions was monitored by AFM, while DLS monitored the change in hydrodynamic properties of elemental S under different dilution conditions. The DPV method was used to determine Sx2- in model solutions and the RL water column, with the highest concentrations measured in samples below the chemocline. The observation of the seasonal dynamics of Sx2- showed that its presence and concentration depend on physico-chemical and microbiological factors. The highest concentrations, up to 89 μM polysulfide S0, were determined in summer during pronounced stratification of the water column and intense microbial activity when purple sulfur bacteria (PSB) predominate, while Sx2- was not detected during periods of weak stratification and occurrence of holomixia
The impact of wolf (Canis lupus) on the presence of jackals (Canis aureus) in Croatia
No full textŠirenje čaglja kontinentalnom Europom i nastanjivanje u područjima na kojima
obitava vuk, postavlja pitanje kako čagalj opstaje uz vuka, većeg pripadnika roda unutar kojeg
postoji i kompeticija i interspecijska agresija. Pojavljivanje vukova i čagljeva na istim mjestima
bilježeno je razdoblju od 01.04.2021. do 30.03.2022 s 39 automatskih kamera na području
Plitvica i 35 na području Knina. Prikupljeno je 563 opažanja vukova i 857 opažanja čagljeva.
Učestalost vukova bila je podjednaka u odabranim dijelovima alpinske i mediteranske
biogeografske regije, a čagljeva bila je 56 puta veća u mediteranskoj regiji u odnosu na alpinsku
regiju. Učestalost čagljeva bila je četiri puta veća od učestalosti vukova u dijelu mediteranske
regije, a 23.3 puta manja u alpinskoj regiji. U mediteranskoj i alpinskoj regiji vukovi i čagljevi
bili su općenito noćno aktivni, što ukazuje na općenito izbjegavanje čovjeka. Tijekom razdoblja
brloženja, vukovi u mediteranskoj regiji su bili aktivni noću i u sumrak, a u alpinskoj tijekom
dana i sumraka. Regionalne razlike u sezonskoj aktivnosti posljedica su različitih obrazaca i
tipova ljudskih aktivnosti. Veći pritisak čovjeka u području mediteranske regije sužava
vremensku nišu vuka na noćno razdoblje, a manji pritisak u području alpinske regije omogućava
aktivnost vuka ravnomjernije raspoređenu tijekom svih doba dana. Čagalj u mediteranskoj
regiji izbjegava prvenstveno čovjeka tako da je aktivan noću, a onda izbjegava i vuka
smanjujući aktivnost kada je vuk najaktivniji. Čagalj u alpinskoj regiji upražnjava svoje životne
potrebe tijekom kraćih i intenzivnijih razdoblja aktivnosti tijekom noći, ali i dana.The expansion of the jackal in continental Europe and its establishment in areas
inhabited by wolves raises the question of how the jackal can survive alongside the wolf, a
larger member of the genus in which there is both competition and interspecific aggression. The
occurrence of wolves and jackals in the same locations was recorded from 01.04.2021 to
30.03.2022 with 39 and 35 automatic cameras in the Plitvice and Knin areas, respectively. 563
wolf observations and 857 jackal observations were collected. The frequency of wolves was
equal in selected parts of the Alpine and Mediterranean biogeographical regions, and the
frequency of jackals was 56 times higher in the Mediterranean region than in the Alpine region.
The frequency of jackals was four times higher than that of wolves in the Mediterranean region
and 23.3 times lower in the Alpine region. In the Mediterranean and Alpine regions, wolves and
jackals were generally active at night, suggesting that they generally avoid humans. During the
denning period, wolves in the Mediterranean region were active at night and dusk, and during
the day and at dusk in the Alpine region. The regional differences in seasonal activity were the
result of different patterns and types of human activity. The higher human pressure in the
Mediterranean region restricts the wolf's temporal niche to the night, while the lower human
pressure in the Alpine region allows a more even distribution of wolf activity throughout the
day. The jackal in the Mediterranean region avoids humans primarily by being active at night
and then avoids the wolf by reducing its activity when the wolf is most active. The jackal in the
Alpine region performs its vital functions during shorter and more intense periods of activity at
night and during the day
DETECTION AND QUANTIFICATION OF STANDARD AND NOVEL BEHAVIORAL ELEMENTS AND THEIR APPLICATION AS BIOMARKERS OF EXPOSURE OF EARTHWORMS (LUMBRICIDAE) AND WATER FLEAS (DAPHNIIDAE) TO MODEL POLLUTANTS
No full textPromjene u ponašanju organizama sve su više prepoznate kao rani i osjetljivi biomarkeri izloženosti zagađivalima. U ovom istraživanju primijenjeni su standardni i predstavljeni su novi bihevioristički elementi modelnih organizama, predstavnika gujavica i vodenbuha. Primjenom tehnika strojnog učenja razvijeni su alati za precizno praćenje promjena u ponašanju organizama pri izloženosti različitim koncentracijama pesticida. Rezultati pokazuju smanjenje aktivnosti pri višim koncentracijama, dok su niže koncentracije u pojedinim slučajevima uzrokovale blagu stimulaciju aktivnosti. Ovakvi bihevioristički odgovori pružaju rane i pouzdane pokazatelje subletalnih učinaka pesticida te nadopunjuju tradicionalne biokemijske pokazatelje. Ovakav pristup kvantifikaciji biheviorističkih elemenata predstavlja inovativan korak u ekotoksikološkim istraživanjima i procjeni ekoloških rizika, s potencijalnom primjenom u sustavima monitoringa i regulaciji uporabe pesticida.Behavioral changes are increasingly recognized as early and sensitive biomarkers of exposure to pollutants. This study applied standard and introduced novel behavioral elements in model organisms, specifically earthworms and water fleas. Using machine learning techniques, tools were developed for precise monitoring of behavioral changes in organisms exposed to various concentrations of pesticides. The results indicate reduced activity at higher concentrations, while lower concentrations in some cases caused slight stimulation of activity. These behavioral responses provide early and reliable indicators of the sublethal effects of pesticides, complementing traditional biochemical biomarkers. This approach to quantifying behavioral elements represents an innovative step in ecotoxicological research and ecological risk assessment, with potential applications in monitoring systems and the regulation of pesticide use
Structural analysis of blood plasma N-glycome from a long-lived naked mole-rat (Heterocephalus glaber Rüppell, 1842)
No full textGolokrtičasti štakor (GŠ) (Heterocephalus glaber Rüppell, 1842) je eusocijalni fosorijalni glodavac čiji je prirodni areal Istočna Afrika, a zbog životnog vijeka koji prelazi 30 godina je atraktivan modelni organizam u biologiji starenja. Molekularni mehanizmi otpornosti na kancerogenezu, neurodegeneraciju, hipoksiju i neke vrste boli povezani su sa održavanjem proteostaze u čemu sudjeluju i posttranslacijske modifikacije proteina. Dinamika i raznolikost glikozilacije proteina u GŠ do sada nije istraživana. U ovom je radu pomoću tekućinske kromatografije i spektrometrije masa provedena strukturna analiza N-glikoma krvne plazme GŠ. Određene su strukture i udjeli 160 različitih N-glikana među kojima se ističe strukturni motiv 4-O-acetilacije sijalinskih kiselina. Glikoproteomskom analizom otkriveno je da takvi sijaloglikani potječu s inhibitora proteaza u krvnoj plazmi te je pretpostavljen njihov zaštitni i stabilizirajući utjecaj na proteine.The naked mole-rat (NMR) (Heterocephalus glaber Rüppell, 1842) is an eusocial fossorial rodent native to East Africa. Its exceptionally long lifespan of over 30 years makes it a popular non-conventional model organism in the biology of ageing and
longevity. Molecular mechanisms underlying resistance to cancerogenesis, neurodegeneration, hypoxia and certain types of pain are related to the maintenance of proteostasis where key players are protein post-translational modifications. The dynamics and diversity of protein glycosylation in NMR are completely unexplored. In this study, a structural analysis of NMR blood plasma N-glycome was performed using liquid chromatography and mass spectrometry. A total od 160 different N-glycans were annotated and quantified. The core structural motif in the N-glycome of NMR was the presence of 4-O-acetylated sialic acids. Employing a glycoproteomic analysis, 4-Oacetylated sialo-N-glycans were pinpointed to plasma protease inhibitors and their protective and stabilizing effect on the proteins was inferred
Palaeoenvironment of Echinoids on the Islet of Trstenik (South of Korčula Island)
No full textNa otočiću Trstenik, južno od otoka Korčule, otkrivene su naslage s ostacima ježinaca. Vršena su mjerenja na tri profila te su prikupljeni uzorci za mikroanalizu. Temeljem odredbe mikrofacijesa vapnenaca i tafonomije ježinaca utvrđen je taložni okoliš koji odgovara plitkomorskom okolišu otvorene unutarnje platforme. Opisani ježinci pripadaju skupini nepravilnih ježinaca, redu Cassiduloida koji su živjeli semi-infaunalno. Stratigrafski raspon proučavanih naslaga određen je temeljem biostratigrafskih raspona rodova bentičkih foraminifera Solenomeris sp., Rhapydionina sp., Cuvillierinella sp. i Spirolina sp. te odgovara rasponu mastriht – eocen.Echinoid-bearing layer was discovered on Trstenik islet, south from the island of Korčula. Field studies were conducted at three outcrops and samples were collected for microanalysis. Based on the microfacies analysis of the limestones and the taphonomy of echinoids, the palaeoenvironment corresponded to the facies zone of a shallow marine setting of the open inner platform. Described echinoids belong to the group of irregular echinoids, the order Cassiduloida, which live semi-infaunal. Benthic foraminifera genera were used to determine the age of the studied deposits which corresponds to Maastrichtian – Eocene range
Bayesian neural networks
No full textU ovom diplomskom radu obrađena je tema Bayesovih neuronskih mreža, koje predstavljaju spoj standardnih neuronskih mreža i Bayesovske statistike. U svrhu razumijevanja Bayesovih neuronskih mreža obrađuju se teme klasičnih neuronskih mreža i Bayesovskog zaključivanja, s naglaskom na Bayesov teorem te priorne i posteriorne distribucije. Detaljno se analizira struktura i razlike Bayesovih neuronskih mreža u odnosu na klasične, s fokusom na metode treniranja poput varijacijskog zaključivanja i Monte Carlo metoda. Mogućnost kvantifikacije neizvjesnosti Bayesovih neuronskih mreža prezentira se kroz uvođenje vrsta neizvjesnosti i njihove teorijske podloge. Za kraj teorijskog dijela, detaljno se analizira problem pretreniranosti u kontekstu strojnog učenja te metode kojima klasične i Bayesove neuronske mreže njemu pristupaju. U eksperimentalnom dijelu, na stvarnim skupovima podataka implementiraju se modeli klasičnih i Bayesovih neuronskih mreža. Kroz rezultate eksperimentalnog dijela pokazuju se mogućnosti Bayesovih neuronskih mreža i prednosti u odnosu na klasične.This thesis explores the topic of Bayesian neural networks, which represent a combination of standard neural networks and Bayesian statistics. To facilitate an understanding of Bayesian neural networks, the concepts of classical neural networks and Bayesian inference are discussed, with an emphasis on Bayes' theorem and prior and posterior distributions. The structure and differences of Bayesian neural networks compared to classical ones are analyzed in detail, focusing on training methods such as variational inference and Monte Carlo methods. The ability of Bayesian neural networks to quantify uncertainty is presented through the introduction of types of uncertainty and their theoretical foundations. The theoretical section concludes with a detailed examination of the problem of overfitting in the context of machine learning and the methods used by classical and Bayesian neural networks to address it. In the experimental section, models of classical and Bayesian neural networks are implemented on real datasets. The results of the experimental section demonstrate the capabilities of Bayesian neural networks and their advantages over classical neural networks
Zodiac cipher
No full textU ovom radu prikazan je sadržaj i povijesni kontekst Zodijakovih šifri, Z408, Z340, Z13 i Z32, te je detaljno opisan postupak dešifriranja istih. Spomenute šifre svojom su složenošću desetljećima zbunjivale stručnjake iz područja kriptografije, forenzike i lingvistike. Iako je živio u doba kada tehnologija nije bila razvijena, Zodijak je uspio kreirati dovoljno složene šifre da ih čak niti moderne tehnologije nisu uspjele dešifrirati. Šifra Z408 šifrirana je kao supstitucijska homofona šifra dok je šifra Z340 i homofonska supstitucijska i transpozicijska šifra.
Zbog razumijevanja rada na početku je posebna pažnja posvećena definiranju supstitucijske i transpozicijske šifre. Glavni dio rada opisuje ključne faze u dešifriranju spomenutih šifri i korištenu metodologiju, uključujući frekvencijsku analizu, prepoznavanje uzoraka i primjenu računalnih algoritama za automatizaciju procesa. Ovim dijelom daje se uvid u kompleksnost dešifriranja i specifične izazove poput nedosljednosti u šifriranju, mogućih grešaka pri pisanju na koje su nailazili kriptografi kroz više od 50 godina.This thesis presents the content and historical context of the Zodiac ciphers, Z408, Z340, Z13, and Z32, and provides a detailed description of the decryption process. These ciphers, with their complexity, have puzzled experts in cryptography, forensics, and linguistics for decades. Despite living in an era where technology was not highly advanced, Zodiac managed to create ciphers complex enough that even modern technologies struggled to decrypt them.
The Z408 cipher was encrypted as a homophonic substitution cipher, while the Z340 cipher combined both homophonic substitution and transposition methods. To ensure a better understanding of the work, particular attention is given at the beginning to defining substitution and transposition ciphers.
The main part of the thesis describes the key phases in decrypting these ciphers and the methodologies used, including frequency analysis, pattern recognition, and the application of computational algorithms to automate the process. This section provides insight into the complexity of the decryption and the specific challenges, such as inconsistencies in encryption and possible writing errors, faced by cryptographers over more than 50 years
LASSO with constraints
No full textGlavni cilj ovog rada je bio dati uvod u LASSO metodu regresijske analize, preciznije LASSO s ograničenjima, objasniti matematičku pozadinu metode te implementirati algoritam za programsko rješavanje problema koji koriste LASSO s ograničenjima. U prvom poglavlju smo iznijeli osnovne matematičke pojmove i pozadinu, dok smo u drugom poglavlju objasnili neke od algoritama za rješavanje problema ograničenog LASSOa. U trećem poglavlju objašnjavamo programsku implementaciju algoritma. Konačno, u četvrtom poglavlju prikazujemo primjenu algoritma na podacima iz stvarnoga svijeta.The main goal of this thesis was to provide an introduction to the LASSO method of regression analysis, more precisely LASSO with constraints, to explain the mathematical background of the method, and to implement an algorithm that will solve problems that use LASSO with constraints. In the first chapter we presented the basic mathematical concepts and background, while in the second chapter, we explained some of the algorithms for solving the constrained LASSO problem. In the third chapter, we explained the software implementation of the algorithm. Finally, in the fourth chapter, we present the application of the algorithm to real-world data
Properties of homo- and heterometallic complexes prepared using tris(oxalato)chromate(III) and tris(oxalato)ferrate(III) building blocks with alkyl-ammonium cations
No full textReakcijama vodenih otopina građevnih blokova [M(C2O4)3]3– (M = Cr3+, Fe3+) koji sadrže katione (CH3)2(C2H5)NH+ odnosno (CH3)(C2H5)2NH+ s jednostavnim solima prijelaznih metala (Cu2+, Mn2+ ili Co2+) uz dodatak N-donorskih liganada priređena su 23 nova spoja s ugrađenim alkil-supstituiranim kationima. Izolirano je 13 heterometalnih (8 [MnIICrIII], 3 [CoIICrIII], 1 [MnIIFeII] i
1 [CoIIFeIII]) i 10 homometalnih (7 [CrIII], 2 [FeIII] i 1 [MnII]) spojeva, različite nuklearnosti i dimenzionalnosti. Svojstva priređenih sustava istraživana su IR- i UV/Vis-spektroskopijom, termičkom analizom, difrakcijom rendgenskih zraka u monokristalu i prahu, te mjerenjem magnetizacije. Električna svojstva odabranih spojeva su istražena impedancijskom spektroskopijom mjerenjem ovisnosti vodljivosti o relativnoj vlažnosti i temperaturi. Tri izabrana heterometalna spoja istražena su kao molekulski prekursori za dobivanje čistih faza oksida spinelne strukture termičkom razgradnjom u jednom koraku. Četiri spinelna oksida su dobivena pirolizom smjese dvaju ili triju oksalatnih kompleksa pomiješanih u odgovarajućem omjeru. Svim oksidima istražena su (mikro)strukturna i optička svojstva, te fotokatalitička aktivnost u razgradnji organskih bojila pod vidljivim zračenjem bez i uz dodatak H2O2, a odabranima magnetska i električna svojstva.By reacting aqueous solutions of the building blocks [M(C2O4)3]3– (M = Cr3+, Fe3+) containing cations (CH3)2(C2H5)NH+ or (CH3)(C2H5)2NH+ with simple salts of transition metals (Cu2+, Mn2+ or Co2+), with the addition of N-donor ligands, 23 new compounds with incorporated alkyl- substituted cations were prepared. 13 heterometallic (8 [MnIICrIII], 3 [CoIICrIII], 1 [MnIIFeII] and 1 [CoIIFeIII]) and 10 homometallic (7 [CrIII], 2 [FeIII] and 1 [MnII]) compounds with different nuclearity and dimensionality were isolated. The properties of the prepared compounds were investigated by IR and UV/Vis spectroscopy, thermal analysis, single-crystal and powder X-ray diffraction and magnetization measurements. The electrical properties of selected compouns were investigated using impedance spectroscopy by measuring the dependence of conductivity on relative humidity and temperature. Three selected heterometallic compounds were investigated as molecular precursors for the preparation of pure oxide phases with spinel structure by thermal decomposition in one step. Four spinel oxides were obtained by pyrolysis of a mixture of two or three oxalate complexes in a suitable ratio. The (micro)structural, optical and photocatalytic properties in the degradation of the organic dyes under visible irradiation without and with addition of H2O2 were investigated for all oxides, as well as the magnetic and electrical properties for selected oxides