Satisfaction of high school biology teachers with a conceptual approach to teaching after the curriculum reform

Cilj ovog diplomskog rada bio je ispitati zadovoljstvo nastavnika biologije gimnazijskih programa s konceptom, razumijevanjem i provedbom važećeg kurikuluma u nastavi te razumijevanje konceptualnog pristupa u poučavanju biologije. Ispitano je postoje li značajne razlike između odgovora nastavnika različite duljine radnog iskustva te postoji li značajan utjecaj duljine radnog iskustva na odgovore nastavnika. Osmišljen je online upitnik koji je, posredovanjem Agencije za odgoj i obrazovanje, poslan nastavnicima biologije. Upitnik je ispunilo 78 nastavnika. Rezultati ankete ukazuju da se nastavnici često susreću s poteškoćama u razumijevanju konceptualnog pristupa i odgojno-obrazovnih ishoda te s poteškoćama u procjeni dubine nastavnog sadržaja. Uglavnom nisu opažene značajne razlike između odgovora nastavnika s različitom duljinom radnog iskustva niti značajan utjecaj duljine radnog iskustva na odgovore nastavnika. Ipak, opaženo je da nastavnici s više od 11 godina radnog iskustva iskazuju veće nezadovoljstvo važećim kurikulumom. Može se zaključiti da nastavnici prepoznaju potencijal nastave biologije temeljene na metodama aktivnog učenja usmjerenih na učenike, međutim, smatraju da važeći kurikulum samo djelomično ispunjava predviđene ishode učenja i očekivanja nastavnika u praksi. Stoga bi bilo dobro omogućiti redovitu reevaluaciju kurikuluma, koja bi uzela u obzir osvrt nastavnika, kao i stalnu sustavnu podršku nastavnicima, kako bi se uspješnije snalazili u ostvarenju odgojnoobrazovnih ciljeva nastavnog procesa.The aim of this thesis was to examine the satisfaction of biology teachers in high school programs with the concept, understanding and implementation of the valid curriculum in teaching and understanding of the conceptual approach in teaching biology. Significant differences between the answers of teachers with different length of work experience as well as the influence of the length of work experience on teachers' answers were examined. An online questionnaire was designed and sent to biology teachers via the Education and Teacher Training Agency. 78 teachers filled out the questionnaire. The results of the survey indicate that teachers often encounter difficulties in understanding the conceptual approach and educational outcomes, as well as difficulties in assessing the depth of the teaching content. No significant differences were observed between the answers of teachers with different length of work experience, nor a significant influence of the length of work experience on teachers' answers. However, it was observed that teachers with more than 11 years of work experience express greater dissatisfaction with the current curriculum. It can be concluded that teachers recognize the potential of teaching biology based on student-centered active learning methods; however, according to the teachers’ responses, the current curriculum only partially fulfills the intended learning outcomes and teachers' expectations in practice. Therefore, it would be beneficial to enable a regular reevaluation of the curriculum that would take into account the teacher's review, as well as constant systematic support for teachers, so that they can navigate more successfully in achieving the educational goals of the teaching process

Optimization of hyaluronidase inhibition method and determination of inhibition by olive leaf extracts (Olea europaea, L.)

Hijaluronska kiselina jedna je od esencijalnih komponenata tkiva koja sudjeluje u održavanju hidratacije, međustaničnoj komunikaciji i djeluje kao fiziološki lubrikant. Hijaluronidaza, kao enzim koji razgrađuje hijaluronsku kiselinu, sve više je u fokusu znanstvenih istraživanja u svrhu prevencije preuranjenog starenja kože i usporavanja progresije pojedinih bolesti. Cilj ovog diplomskog rada bila je optimizacija spektrofotometrijske metode inhibicije hijaluronidaze i njezina primjena na ekstraktima lista masline. U eksperimentima je korištena hijaluronidaza iz goveđih testisa i natrijeva sol hijaluronske kiseline. Metoda je prilagođena laboratorijskim uvjetima i primijenjena na ekstraktima lista masline te je ispitan njihov inhibicijski potencijal za enzim hijaluronidazu. Pozitivna kontrola bila je taninska kiselina, no najniži IC50, odnosno ukupno najjaču inhibiciju ostvarilo je otapalo B (IC50=3,47 ± 1,45 μg/mL; sastav: 28,8% PPG, 63,8% destilirana voda, 7,4% mliječna kiselina). Najsnažniju inhibiciju među ekstraktima pokazao je uzorak B042M, s IC50 vrijednošću od 4,91 ± 0,56 μg/mL. IC50 vrijednosti čistih otapala (A i B) usporedive su s IC50 vrijednostima dobivenima za ekstrakte priređene s pripadajućim otapalima, stoga se može zaključiti kako sama otapala najviše utječu na izmjerenu inhibiciju. Za potvrdu i točnije definiranje inhibicijskog učinka sastavnica iz lista masline potrebno je provesti dodatna istraživanja.Hyaluronic acid is an essential component of tissues and some of its roles are retaining hydration, intercellular communication, and lubrication. Hyaluronidase, as an enzyme that degrades hyaluronic acid, attracts the attention of researchers who study premature skin aging and different diseases connected to disbalanced hyaluronan homeostasis. The goal of this diploma thesis is to optimize the spectrophotometric method for determining hyaluronidase inhibition. Bovine testicular hyaluronidase was the experimental enzyme and sodium hyaluronate was its substrate. The method has been adjusted to laboratory requirements and was used for measuring hyaluronidase - inhibiting potential of olive leaf extracts. Tannic acid was used as positive control, but the lowest IC50 and overall strongest inhibition was exhibited by solvent B (IC50=3,47 ± 1,45 μg/mL; 28,8% PPG, 63,8% purified water, 7,4% lactic acid). Sample B042M exhibited the strongest inhibition of all the extracts, with IC50 of 4.91 ± 0.56 μg/mL. IC50 values of pure solvents (A and B) is comparable to the values measured for the extracts. This result indicates that the solvents alone act as strong inhibitors of the hyaluronidase enzyme. For exact defining of inhibition by olive leaf extracts, more research needs to be done

The influence of physical activity on central nervous system

U ovom radu napravljen je kratki pregled nekih zanimljivih medijatora utjecaja fizičke aktivnosti na središnji živčani sustav. Sama reakcija tijela na fizičku aktivnost je kompleksan događaj s nizom otpuštenih hormona i metabolita koji reguliraju metabolizam energije, kao i vodni metabolizam. Neki od tih faktora utječu i na funkcije mozga. Β-endorfin djeluje analgetički, uzrokujući tzv. „runner's high“ osjećaj kod dugometražnih trkača. Fizička aktivnost modulira aktivnost serotonergičkog i dopaminergičkog sustava, čija disfunkcija igra ulogu u mehanizmima depresije i stvaranja ovisnosti. Vježbanje je povezano i s izlučivanjem BDNF-a, neurotrofnog faktora s ulogama u induciranju procesa sinaptičke plastičnosti, svojstva živčanog sustava na kojem se temelje različite kognitivne funkcije. Kratkotrajna fizička aktivnost može potaknuti otpuštanje oreksina u mozgu, aktivirajući tako budnost i pažnju, između ostalog. Laktat, koji je u prošlosti bio smatran samo nusproduktom anaerobnog metabolizma, pokazan je kao izvor energije neurona i modulator različitih moždanih funkcija, s dodatnom potencijalnom ulogom u prevenciji kognitivnih poremećaja povezanih sa starošću. Sve skupa upućuje na mozak ne samo kao organ za razmišljanje nego kao i organ za kretanje.In this paper, a brief overview of some interesting mediators of the impact of physical activity on the central nervous system is provided. The body's response to physical activity itself is a complex event involving the release of hormones and metabolites that regulate energy metabolism and water metabolism. Some of these factors also influence brain functions. Βendorphin acts as an analgesic, causing the so-called "runner's high" feeling in long-distance runners. Physical activity modulates the activity of the serotonergic and dopaminergic systems, whose dysfunction plays a role in the mechanisms of depression and addiction. Exercise is also associated with the secretion of BDNF (brain-derived neurotrophic factor), which has roles in inducing synaptic plasticity processes, the neuronal properties underlying various cognitive functions. Short-term physical activity can stimulate the release of orexin in the brain, thus activating wakefulness and attention, among other things. Lactate, which was previously considered only a byproduct of anaerobic metabolism, has been shown to serve as an energy source for neurons and a modulator of various brain functions, with additional potential roles in the prevention of age-related cognitive disorders. All of this suggests that the brain is not only an organ for thinking but also an organ for movement

Adsorption of cobalt ions on pistachio shells : diploma thesis

U ovom je diplomskom radu ispitana adsorpcija kobaltovih iona na ljuskama pistacija u ovisnosti o različitim početnim koncentracijama otopina kobaltovih iona (3,543; 7,028; 10,061; 17,138 te 24,452 mmol dm -3 ) pri stalnoj temperaturi od 303 K, brzini miješanja od 200 okr min -1 , u trajanju od 96 h. Uočava se, na temelju dobivenih rezultata, eksponencijalan porast količine adsorbiranih kobaltovih iona na ljuskama pistacija ( qe ) s porastom početne koncentracije kobaltovih iona u otopini ( c0 ). Pri najvišoj odabranoj koncentraciji postignute su i maksimalna vrijednost količine adsorbiranih kobaltovih iona koja iznosi qe = 0,529 mmol g -1 i najviša učinkovitost adsorpcije kobaltovih iona koja iznosi 10,826%. Uzimajući u obzir izračunate vrijednosti za koeficijent korelacije R 2 može se zaključiti kako Langmuirov adsorpcijski model bolje opisuje adsorpciju kobaltovih iona na ljuskama pistacija od Freundlichovog adsorpcijskog modela.In this diploma thesis, the adsorption of cobalt ions on pistachio shells was studied depending on different initial concentrations of cobalt ions solutions (3.543, 7.028, 10.061, 17.138 and 24.452 mmol dm -3 ) at a constant temperature of 303 K, a stirring speed of 200 rpm -1 for 96 h. Based on the results obtained, an exponential increase in the amount of adsorbed cobalt ions on pistachio shells ( qe ) with an increase in the initial concentration of cobalt ions in solution ( c0 ) was observed. At the highest selected concentration, the maximum value of the amount of adsorbed cobalt ions, with the value of qe = 0.529 mmol g -1 , and the highest adsorption efficiency of cobalt ions, with the value of 10.826%, were achieved. Taking the calculated values for the correlation coefficient R 2 into account, it can be concluded that the Langmuir adsorption model better describes the adsorption of cobalt ions on pistachio shells unlike the Freundlich adsorption model

Experiences and habits of specialty coffee consumption among consumers in Croatia

Konzumacija i proizvodnja specialty kave rastući je trend u industriji kave u posljednja dva desetljeća. Cilj ovog istraživanja je ispitati razlike između potrošača kave, onih koji konzumiraju i onih koji ne konzumiraju specialty kavu, u sociodemografskim obilježjima, iskustvu i navikama konzumacije te znanju i percepciji koncepta pravedne trgovine. Istraživanje je provedeno putem online anketnog upitnika na uzorku od 201 sudionika. Većina sudionika živi u gradu Zagrebu, zaposleni su te prosječnog životnog standarda. Sudionici najčešće piju tursku ili espresso kavu u društvu prijatelja u kafiću kako bi odmorili te zbog smirujućeg djelovanja kave. Potrošači specialty kave navode kako specialty kava ima prepoznatljiv i bolji okus i aromu. Koristeći podatke dobivene ovim istraživanjem, marketinški stručnjaci i ugostitelji mogu bolje uvidjeti preferencije potrošača te prema njima kreirati marketinške strategije.The consumption and production of specialty coffee is a growing trend in the coffee industry in the last two decades. The aim of this research is to examine the differences between coffee consumers, those who consume and those who do not consume specialty coffee, in sociodemographic characteristics, consumption experience and habits, and knowledge and perception of the concept of fair trade. The research was conducted through an online questionnaire on a sample of 201 participants. Most of the participants live in the city of Zagreb, are employed, and have an average standard of living. Participants usually drink Turkish or espresso coffee in the company of friends in a cafe to rest and because of the calming effect of coffee. Consumers of specialty coffee state that specialty coffee has a recognizable and better taste and aroma. Using the data obtained from this research, marketing experts and restaurateurs can better understand consumer preferences and create marketing strategies according to them

Influence of porosity on the mechanical behaviour of glass fibre-reinforced PBT resin

Ovaj diplomski rad je napravljen u suradnji Yazaki Europe Ltd. Yazaki je jedna od svjetskih proizvođača električnih komponenata za automobilsku industriju. Između ostalog bave se proizvodnjom, razvojem i istraživanjem električnih distributivnih sistema (EDS), elektroničnih komponenata i instrumenata, konektora i terminala. Na cijel skup proizvoda se postavljaju visoki zahtjevi koji uključuju dobre mehaničke i električne karakteristike, te otpornost na toplinu i tekućine. Rad je izrađen sa ciljem da se analizira jedan od problema koji se javlja kao posljedica injekcijskog prešanja komponenata kompleksnih geometrija. Materijal koji se analizira je heterogen i anizotropan te sastoji se od osnovnog PBT-a (Polibutilen tereftalat) i staklenih vlakana (GF) čiji udio može biti raznovrstan, no uzet će se vrijednost od 20%. S obzirom da se takva miješana talina ubrizgava u kalup koji je složene geometrije, zbog lošeg strujanja i struganja po površini kalupa, talina ne uspijeva kvalitetno ispuniti kalup i dolazi do pojavljivanja poroznosti. Poroznost za posljedicu ima smanjenje mehaničkih svojstava i cilj ovog rada je analizirati kakav je upravo taj utjecaj poroznosti. Staklena vlakna, u obliku štapića, koja se dodaju u osnovni PBT materijal su izrazito mala i njihovo modeliranje stvara određene probleme, kao što je nemogućnost definiranja realne geometrije i dimenzija. Pretpostavljeno je linearno ponašanje konstituenata i male deformacije. Područje istraživanja ovog rada se može podijeliti u četiri cjeline: 1. Istražiti svojstva anizotropnih i heterogenih materijala te proučiti metode homogenizacije pomoću kojih ih je moguće opisati sa ciljem određivanja mehaničkih karakteristika. 2. Odrediti 2D i 3D reprezentativne volumenske elemente (RVE) materijala koji se sastoje od PBT-a i 20% staklenih vlakana i pronaći veličinu RVE-a pomoću kojega je moguće na mikro razini opisati mehaničko ponašanje materijala na makro razini. 3. Uz PBT i 20% staklenih vlakana, modelirati reprezentativne volumenske elemente (RVE) sa udjelom pora. 4. Dobivene numeričke rezultate usporediti sa vrijednostima dobivenima eksperimentom. U prvom i drugom poglavlju su opisana heterogena i anizotropna svojstva materijala. Materijal koji se proučava je heterogen jer se sastoji od osnovne faze, Polibutilen tereftalata i uključina u obliku staklenih vlakana, a orijentacije vlakana je raznovrsna te se može reći da je materijal i anizotropan. Također je proučena metoda homogenizacije heterogenih materijala, od kojih je posebno izdvojena Mori-Tanaka metoda. U trećem poglavlju se pomoću programskog paketa Digimat provela analitička MF (Mean-field) homogenizacijska metoda i rezultati su se uspoređivali sa rezultatima proizvođača materijala. U četvrtom poglavlju su se pomoću Digimat-a i Abaqus-a, generirale različite veličine 2D i 3D reprezentativnih volumenskih elemenata (RVE-a) materijala sa različitim orijentacijama staklenih vlakana. Razmatrale su se 3 različite orijentacije staklenih vlakana te 4 različite veličine RVE-a. Svi dobiveni rezultati su se uspoređivali sa - dijagramom i tražili su se oni modeli koji dobro opisuju stvarno ponašanje materijala uz uvjet da daljnjim povećanjem RVE-a ne dolazi do značajne promjene u dobivenim rezultatima. Razmatrala se periodična geometrija sa nametnutim periodičnim opterećenjem i rubnim uvjetima. U petom poglavlju je bio cilj provesti analizu modela iz prethodnog poglavalja no uz dodatak pora u materijalu. Odabran je RVE određene veličine i određene orijentacije vlakana iz razloga što se pokazalo da dobro opisuje stvarno ponašanje materijala te uz daljnje povećanje geometrije ne dolazi do značajnih promjena u rezultatu. S ciljem usporedbe dobivenih rezultata, proveo se eksperiment na testnom uzorku epruvete. Epruvete su dobivene postupkom injekcijskog prešanja uz poseban dodatak Hidrocerola čije prisustvo je omogućilo nastanak proznosti unutar strukture materijala. Kako bi se analiza i eksperiment što kvalitetnije usporedili, epruvete su posnimane CT metodom, te su dobivene vrijednosti volumnog udjela i prosječne veličine pora, koje su onda korištene u generiranju računalnih modela. Tlačni test na epruvetama je napravljen i rezultati dobiveni DIC (Digital Image Correlation) metodom su služili za usporedbu numeričkih rezultata sa eksperimentom. Zadnje poglavlje sadrži zaključke provedenog istraživanja i njemu su dane upute za daljnji rad.This thesis is made in collaboration with Yazaki Europe Ltd. Yazaki is one of the world's manufacturers of electrical components for the automotive industry. Among other things, they are engaged in the production, development and research of electrical distribution systems (EDS), electronic components and instruments, connectors and terminals. The entire product set is subject to high requirements that include good mechanical and electrical performance, as well as resistance to heat and fluids. This thesis is made with goal to analyze one of the problems that occurs as a result of injection molding of components of complex geometries. The material to be analyzed is heterogeneous and anisotropic and consists of basic PBT (Polybutylene terephthalate) and glass fiber (GF) whose fraction may be varied, but 20% will be taken. Because such mixed melt is injected into a mold of extremely complex geometries, due to poor flow and scraping on the mold surface, the melt fails to fill the mold well and porosity occurs. Porosity results in a decrease in mechanical properties and the aim of this thesis is to analyze exactly what the effect of porosity is. Glass fibers in the form of sticks that are added to the basic PBT material are extremely small and their modeling creates certain problems, such as the inability to define realistic geometries and dimensions. The linear behavior of the constituents and the small deformations were assumed. The research area of this thesis can be divided into four sections: 1. Investigate the properties of anisotropic and heterogeneous materials and study homogenization methods that can be used to determine mechanical properties. 2. Determine 2D and 3D representative volume elements (RVE) of materials consisting of PBT and 20% fiberglass and find the size of the RVE by which it is possible to describe at the micro level the mechanical behavior of the material at the macro level. 3. With PBT and 20% glass fiber, model representative volume elements (RVEs) with porosity 4. Validate numerical results by comparison with the experiment. The first and second Chapter describe the heterogeneous and anisotropic properties of the material. The material under study is heterogeneous because it consists of the basic phase, polybutylene terephthalate and glass fiber inclusions, and the fiber orientation is varied and can be said that material is anisotropic. The method of homogenization of heterogeneous materials was also studied, of which the Mori-Tanaka method is singled out. In Chapter three, an analytical MF (Mean-field) homogenization method was implemented using the Digimat software package and the results are compared with those of the material manufacturer. In Chapter four, different sizes of 2D and 3D representative volume elements (RVEs) of materials with different glass fiber orientations are generated using Digimat and Abaqus. Three different orientations of glass fibers and four different sizes of RVE were considered. All the results obtained were compared with the - diagram and those models that required a good description of the actual behavior of the material were sought, provided that further increase in RVE did not lead to a significant change in the results obtained. Periodic geometry with imposed periodic loading and boundary conditions was considered. In Chapter Five, the aim was to carry out an analysis of the models in the previous chapter but with the addition of pores in the material. A RVE of a certain size and a specific fiber orientation was selected for the reason that it was shown to describe well the actual behavior of the material and that with a further increase in geometry no significant changes in the result occurred. In order to compare the results obtained, an experiment was conducted on a test sample of the test tube. The tubes were obtained by injection molding with the special addition of Hydrocerol, the presence of which allowed the formation of a pores within the material structure. In order to better compare the analysis and the experiment, the tubes were imaged using the CT method, and the values of volume fraction and average pore size were obtained, which were then used in the generation of computer models. A tensile test on the tubes is made and the results obtained by the DIC (Digital Image Correlation) method were used to compare the numerical results with the experiment. The last chapter contains the conclusions of the research conducted and is given directions for further work. Key words: polybutylene terephthalate, glass fibers, porosity, Mori Thin method, homogenization, finite element method, representative volume element (RVE), Abaqus, Digima

Population affinity estimation: the frequency of the metopic sature on Salona population

Cilj: Cilj ovoga rada jest utvrditi učestalost perzistentnog metopičnog šava u odrasloj populaciji Salone. Metode: Pregledani su koštani ostatci s arheološkog nalazišta Solin-Smiljanovac. Od koštanih ostataka 629 osoba, njih je 142 (68 žene, 66 muškarci, 8 nepoznatog spola) pripadalo je odraslim osoba (starijima od 18) te je imalo očuvanu frontalnu kost na kojoj se mogla odrediti prisutnost perzistentnog metopičnog šava te radi li se o potpunom ili nepotpunom. Nepotpuni metopični šav je potom dodatno definiran prema tipu (donji, srednji ili gornji). Donji tipovi su podijeljeni dalje prema obliku (U, V, H, Y, obrnuti Y, side-to-side, zrakasti, linearni i dvostruki). U istraživanju nije napravljena distinkcija između donjeg metopičnog šava i supranazalnog šava. Podatci o spolu, dobi, očuvanosti frontalne kosti te tipu i obliku metopičnog šava su bilježeni u tablice a metopični šavovi su fotografirani. Rezultati: Perzistentni metopični šav zabilježen je na 78 od 142 lubanje (54,93%), na 45 muških lubanja i 35 ženskih. Nepotpuni metopični šav/supranazalni šav zabilježen je na 67 lubanja, 36 muških i 29 ženskih lubanja (47,18%). Na 10 lubanja zabilježen je metopizam (5 muških, 5 ženskih). Zaključak: Prisutnost perzistentnog metopičnog šava u Saloni slična je onoj zabilježenoj u istraživanjima provedenima na geografski i vremenski bliskim populacijama. Buduća istraživanja na području današnje RH bi dala uvid u prisutnost perzistentnog metopičnog šava kroz povijest Hrvatske te ukazala na važnost proučavanja epigenetskih karakteristika.Objective: The objective of this paper is to determine the frequency of the presence of persistent metopic suture in the adult population of Salona and to contribute to the research of persistent metopic suture and epigenetic characteristics in anthropology and forensics. Methods: Skeletal remains from the Solin-Smiljanovac archaeological site were examined. Of the skeletal remains of 629 persons, 142 of them (68 women, 66 men, 8 of unknown sex) belonged to adults (older than 18) and had a preserved frontal bone on which the presence of a persistent metopic suture could be determined and whether it was a complete or incomplete. The incomplete metopic suture was then further defined by type (lower, middle or upper). The types below are further divided by shape (U, V, H, Y, inverted Y, side-to-side, radial, linear and double). In the research, no distinction was made between the lower metopic suture and the supranasal suture. Data on sex, age, preservation of the frontal bone, and the type and shape of the metopic suture were recorded in tables, and the metopic sutures were photographed. Results: Persistent metopic suture was recorded in 78 skulls (54.93%), in 45 male and 35 female skulls. Incomplete metopic suture/supranasal suture was recorded in 67 skulls, 36 male and 29 female skulls (47.18%). Metopism was recorded on 10 skulls (5 male, 5 female). Conclusion: The presence of a persistent metopic suture in Salona is similar to that recorded in studies conducted on geographically and temporally close populations. Further research on the territory of today's Republic of Croatia would provide insight into the presence of a persistent metopic suture throughout the history of Croatia and would point to the importance of studying epigenetic characteristics

Croatian Parliament

Rad ne sadrži sažetak

Attitudes on the Visual Content of Tourist Destination on Instagram

Diplomski rad temelji se na istraživanju stavova o vizualnom sadržaju turističkih destinacija na Instagramu. S obzirom na to da su društveni mediji značajni u promociji turizma, korisnici većinu potrebnih informacija traže na njima, posebno na Instagramu koji nudi širok spektar vizualnog sadržaja. Temeljni članak za ovaj rad je prema Egger i Yu (2021.) koji ističe da boje imaju velik značaj u komunikaciji turističkih destinacija na društvenim medijima. Stoga se u ovom radu istražio utjecaj boja na stavove o vizualnom sadržaju na društvenim medijima, točnije stavove o objavama na Instagramu. Za potrebe ovog rada provedeno je istraživanje metodom kvazi-eksperimenta na namjernom prigodnom uzorku ispitanika. Putem anketnog upitnika prikupljeno je 115 ispitanika te je daljnja analiza rezultata pokazala da boje utječu na stav o vizualnom sadržaju turističkih destinacija na Instagramu. Analizom rezultata utvrđeno je da je ispitanicima plava boja privlačnija od narančaste te da se više slažu sa stavovima (zanimljivost, sviđanje, ugodno, privlačno, dojmljivo) kod objava turističkih destinacija koje sadrže plavu boju s temom prirode.The thesis is based on research towards attitudes on the visual content of tourist destinations on Instagram. Given that social media are significant in promoting tourism, users seek most of the information they need on them, especially on Instagram, which offers a wide range of visual content. The basic article for this work is according to Egger Yu (2021), who points out that colors are of great importance to the communication of tourist destinations on social media. Therefore, this paper explored the impact of colors on attitudes about visual content on social media, more precisely, attitudes about posts on Instagram. For the purposes of this work, quasi-experimental research was conducted on a purposeful image convenient non-probablistic sample of respondents. 115 responses were collected through a questionnaire, and further analysis of the results showed that colors have an influence on the attitude towards the visual content of tourist destinations on Instagram. Analysis of the results found that the blue color was more attractive than orange to respondents and that they have a more positive attitude (appealing, good, pleasant, favorable, likable) towards tourist destinations that use blue colors in nature-themed posts on social media

Modeling tourist consumption using statistical learning methods

U ovom radu modelirala se turistička potrošnja u Republici Hrvatskoj koristeći metode statističkog učenja. Na početku rada dali smo uvod u statističko učenje, uveli terminologiju, centralne pojmove najbolje veze i funkcije gubitka te cijeli okvir za daljnje predstavljanje metoda koje smo koristili. Podsjetili smo se linearnog regresijskog modela i najčešće metode njegove prilagodbe - metode najmanjih kvadrata. Definirali smo pojmove testne greške i očekivane testne greške te predstavili metodu unakrsne validacije kao metodu za procjenu očekivane testne greške. Koristeći lemu o dekompoziciji očekivane testne greške, objasnili smo odnos pristranosti i varijance u statističkom učenju. Potom smo uveli metode odabira prediktora u linearnim modelima te metode regularizacije (ridge i LASSO regresija). Na kraju smo predstavljene metode primijenili na podatke Instituta za turizam o turističkoj potrošnji u Republici Hrvatskoj. Rezultati svih metoda koje smo primijenili upućuju na nelinearnost veze između varijabli odziva i varijable prediktora. Sve metode dovode do približno jednakih zaključaka vezano uz utjecaj pojedinih prediktora na odziv. S obzirom da je testna greška najmanja kod metoda ridge i LASSO regresije, za njih bismo se najprije odlučili pri donošenju zaključaka.In this thesis, we model tourist expenditure in the Republic of Croatia using statistical learning methods. The thesis begins with an introduction to the statistical learning terminology, its concepts and its main tools. We then further revise the linear regression model and the least squares method. Next, we define the test error and the expected test error of a prediction and we present the cross-validation method as a tool for estimating the expected test error. We also provide a decomposition of the expected test error which explains the relationship between bias and variance in the statistical learning theory. We next discuss subset selection methods in linear models and regularization methods (ridge and LASSO). Finally, we apply the presented methods to the data provided by the Institute for Tourism on tourist expenditure in the Republic of Croatia. The results of all the methods we apply suggest a non-linear relationship between the response variable and the predictor variables. However, they also lead to a similar conclusion on the relationship between the response variable and the regressors, with regularization methods giving lower test error