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The role of work-life balance satisfaction in understanding the outcomes of organizational work-life balance support
No full textDoktorski rad je usmjeren na istraživanje uloge zadovoljstva ravnotežom poslovnoga i privatnoga života u odnosu između organizacijske potpore ravnoteži poslovnoga i privatnoga života i njenih ishoda na razini zaposlenika i organizacija. U teorijskom dijelu rada sistematizirane su definicije i pojmovi u području, predstavljen je povijesni razvoj te ključne teorije. Prikazana je važnost ravnoteže poslovnoga i privatnoga života za pojedince i društvo, dok je u središnjem dijelu rada razmotrena organizacijska potpora ravnoteži poslovnoga i privatnoga života te je predstavljen konceptualni model upravljanja ravnotežom poslovnoga i privatnoga života u organizacijama. Naglasak je stavljen na zadovoljstvo ravnotežom poslovnoga i privatnoga života kao pokazatelj ravnoteže poslovnoga i privatnoga života. U empirijskom dijelu rada prikazani su metodologija i rezultati kvalitativnog istraživanja važnosti pojedinih praksi za osiguravanje ravnoteže poslovnoga i privatnoga života, a potom i rezultati kvantitativnog istraživanja uloge zadovoljstva ravnotežom poslovnoga i privatnoga života u odnosu između organizacijske potpore ravnoteži poslovnoga i privatnoga života i ishoda na razini pojedinaca i organizacija. Nalaz kvalitativnog dijela istraživanja rezultirao je popisom 38 ključnih praksi za osiguranje ravnoteže poslovnoga i privatnoga života zaposlenika, dok su kroz rezultate kvantitativnog istraživanja stečeni brojni uvidi u odnose između organizacijske potpore ravnoteži poslovnoga i privatnoga života i ishode na razini pojedinaca i organizacija uz središnju ulogu koncepta zadovoljstva ravnotežom poslovnoga i privatnoga života.The doctoral dissertation focuses on exploring the role of work-life balance satisfaction in the relationship between organizational work-life balance support and its outcomes at both the employee and organizational levels. The theoretical part of the thesis systematizes existing definitions and key concepts in the field and presents the historical development and core theoretical foundations. It highlights the importance of work-life balance for individuals and society, while the central section discusses organizational work-life balance support and introduces a conceptual model for managing work-life balance within organizations. Particular emphasis is placed on work-life balance satisfaction as an indicator of achieved work-life balance. The empirical part of the thesis presents the methodology and findings of a qualitative study on the relevance of work-life balance practices, followed by the results of a quantitative study examining the role of work-life balance satisfaction in the relationship between organizational support and outcomes at the individual and organizational levels. The qualitative research resulted in a list of 38 key work-life balance practices, while the quantitative findings provided numerous insights into the relationship between organizational support and various outcomes, with work-life balance satisfaction playing a central role
Impact of characteristic of electronic scolarly journals on digital archiving management
No full textUvidom u obilježja elektroničkih znanstvenih časopisa koji su počeli izlaziti 2012. godine, u radu su identificirane i istražene one kategorije časopisa koje su najugroženije glede dugoročnog očuvanja, pri čemu su usporedno analizirani digitalno arhivirani i nearhivirani časopisi. Cilj rada bio je utvrditi vezu između određenih obilježja znanstvenih časopisa i njihova digitalnog arhiviranja. Deskriptivna obilježja znanstvenih časopisa preuzeta su iz baze Ulrichsweb, dok je status o digitalnom arhiviranju časopisa provjeravan u registru Keepers. Bibliometrijska analiza časopisa provedena je prema pokazateljima iz baze podataka Web of Science. Kategorizacija izdavača ispitivanih časopisa, kao i agencija za arhiviranje, provedena je temeljem podataka dobivenih anketnim upitnikom te temeljem relevantne literature. Ishodima istraživanja dobivena su saznanja o digitalnom arhiviranju znanstvenih časopisa, a na temelju kategorizacije časopisa, izdavača te agencija za arhiviranje, predložen je model primjerenosti agencija za arhiviranje pojedinoj kategoriji izdavača, odnosno časopisa.The thesis provides an insight into the characteristics of electronic scholarly journals published since 2012. It identifies and examines the categories of journals that are most at risk in terms of long-term preservation, by analysing digitally archived and non-archived journals. The aim of this thesis is to determine the relationship between the characteristics of scholarly journals and their digital archiving. The descriptive characteristics of scholarly journals were obtained from the Ulrichsweb database, while the digital archiving status of the journals was checked in the Keepers Registry. The bibliometric analysis of the journals was carried out using indicators from the Web of Science database. The categorisation of the publishers of surveyed journals as well as archiving agencies, was based on the data from the questionnaire, as well as on relevant literature. The results of the research expand the knowledge about digital archiving of scientific journals. Based on the categorisation of scholarly journals, publishers and archiving agencies, a suitability model for archiving agencies and particular categories of publishers or journals is proposed
The modernism of Kosta Angeli Radovani's figural sculptures
No full textDoktorska disertacija Modernizam figuralne plastike Koste Angelija Radovanija bavi se utvrđivanjem modernističkih značajki i izvora modernizma figuralne plastike Koste Angelija Radovanija (1916. – 2002.), te istraživanjem njegova cjelokupna opusa. Provedena je sustavna i cjelovita monografska obrada kiparskog opusa u kontekstu onodobne nacionalne i međunarodne likovne scene, te je prvi put sastavljen katalog svih poznatih djela ovog umjetnika. Istraženi su akt i portret, medaljerski opus, javna skulptura, spomenička plastika, crtež i grafika, njegov spisateljski opus, pedagoški doprinos te kulturno-društveni angažman. Učinjena je analiza i vrednovanje spomeničke i komorne plastike i načina rada, definiranje tipologije kao i interpretacija akta i portreta te formalna analiza i valorizacija važnijih radova. Djela su sistematizirana po vrsti, tehnici, temi i kompozicijskim rješenjima, te stilskomorfološkim značajkama. Istraživanje je dovelo do nekoliko novih hipoteza o ovom kompleksnom opusu, počevši od teze o dugotrajnom formativnom razdoblju. Utvrđeno je da iako nikada nije napustio figuraciju i prepoznatljivost antropomorfnog motiva te se koristio tradicionalnim materijalima i oblikovnim načelima, na formalnoj i konceptualnoj razini njegov način oblikovanja pripada umjerenom modernizmu. Taj se oblik modernizma razlikuje od prevladavajućeg apstraktnog izraza koji je u Hrvatskoj obilježio stilsku pojavu poslijeratnog visokog modernizma. Opus Koste Angelija Radovanija za dio likovne kritike nije bio dovoljno avangardan, a za drugi dio stručne javnosti nije bio dovoljno tradicionalan. Istraživanje je pokazalo da je uvodio inovacije u prikaz akta i portreta, te da je u tom području oblikovanja ostvario značajan doprinos u hrvatskom poslijeratnom kiparstvu modernizma. Ovo istraživanje, među ostalim, upućuje na to da je pri formiranju modernističkog izraza asimilirao mnogobrojne utjecaje – kiparstvo europskog modernizma, utjecaje izvaneuropskih kultura i drugih vrsta »primitivizama« i arhaizama. Disertacija donosi nove spoznaje o radu i djelovanju autora koje nadopunjuju, proširuju, te omogućuju novi pogled na neke aspekte dosadašnjih istraživanja kao i na cjelokupan opus. Ostvario je jedinstven i prepoznatljiv opus koji predstavlja značajan doprinos hrvatskoj i europskoj modernističkoj figuralnoj plastici.The doctoral dissertation focuses on the determination of modernist features and sources of modernism in the figural sculpture of Kosta Angeli Radovani (1916–2002), as well as on the research into his entire artistic oeuvre. A systematic and complete monographic analysis of his sculptural oeuvre was carried out in the context of the local and international artistic scene of the time. Figurative sculpture (nude and portrait), medal design oeuvre, public sculpture, memorial monuments, drawing, and prints were explored. The dissertation brings an interpretation of his creative oeuvre, as well as new knowledge of his pedagogical contribution and his cultural and social involvement. An analysis and evaluation of memorial and intimate sculpture and methods of work, the definition of typology as well as the interpretation of nudes and portraits and formal analysis and valorization of his more important works were carried out. The works were systematized by type, technique, theme and compositional solutions, as well as by stylistic and morphological features. After collecting data on the works, and, where necessary, also on their attribution, dating and photography, a catalog of all known works of this artist was created for the first time. Then, we analyzed the modernity of his artistic approach to the traditional theme of nude and portrait, which he formed using traditional materials and shaping principles. All this led us to new knowledge about the artist's work and activity. At the beginning of the dissertation, we set up the hypotheses for the scientific research work: 1. Although he never abandoned the figuration and recognizability of the anthropomorphic motif—using traditional materials and shaping principles—on a formal and conceptual level, his style of shaping belongs to moderate modernism; 2. He introduces innovations in the representation of nudes and portraits; 3. In the field of shaping female nudes and portraits, he makes a significant contribution to Croatian post-war sculpture of modernism; 4. Kosta Angeli Radovani's version of modernism differs from the prevailing abstract expression that, in Croatia, was associated with the concept of post-war modernism (for some, it was not avant-garde or traditional enough); 5. During the formation of modernist expression, he assimilated numerous influences — the sculpture of European modernism, the influences of non-European cultures, and other types of "primitivisms" and archaisms. In the introductory chapters, the methodology, hypotheses, and objectives of the scientific research work are presented, as well as is an overview of earlier research and critical reviews of literature. Then, the socio-political context and its influence on the sculptor's formative period were analyzed. A thesis is presented about the unusually long formative period (1926– 1952), which was divided into two parts—conditioned by both the social and artistic as well as cultural context, and by life circumstances of Kosta Angeli Radovani. The first part of the formative period includes the childhood and the creation of student works, as well as studies at the Brera Academy in Milan. When he went to study in Milan, he left the original influences of classics, then French modern sculpture, Aristide Maillol in the nude, and Charles Despiau in the portrait. At that time, his approach to shaping and interest in the subjects of nude and portrait was directed by his professor, a post-Donatellian artist Francesco Messina, who taught sculpture guided by the syntagm, "Do not invent!". The Italian art was dominated by figuration, and Milan was the center of the artistic movement of the Novecento. He gained insights into recent phenomena by following the program of Milan's avant-garde Galleria il Milione, which exhibited abstraction, as well as by studying works of sculptors who introduced modernism into the shaping of traditional subjects of nude and portrait (Arturo Martini, Giacomo Manzù, Marino Marini). He assimilated further influences during his numerous student trips through Italy. He was particularly impressed by the art of Etruscans, ancient Egyptians, and other ancient civilizations, as well as by medieval heritage. Presented are the circumstances and direct influences that determined the formation of his artistic expression. The source of his specific modernism is also analyzed and interpreted. After completing his studies and returning to Zagreb, the second part of his formative period begins (1939–1952). He spends the war years in Zagreb, where he attends a specialization at the Academy of Fine Arts in Zagreb. Until 1945, the bulk of his oeuvre consists of female nudes, portraits, and drawings that show the sculptor's need to free himself from previous influences, searching for his own expression. In that period, there is an increasingly pronounced stylization and reduction of the representation. After the end of the war, Angeli Radovani adjusts to the socio-political circumstances of the time. Socialist realism was a politically and state imposed doctrine, so, in the artistic expression, there were changes in themes of representation and shaping. Angeli Radovani covers the then naked female body with clothes because the motif of the nude is contrary to new socialist morality. He shows figures in the context of labor and social responsibility. The volume is closed, and the selection of themes limited. Until the end of the 1940s, he models within the framework of a realistic style of shaping, while his portraits of national heroes are influenced by socialist realism. For his Portrait of Nada Dimić (Portret Nade Dimić; 1947) he won the third prize of the Committee for Culture and Art of the Government of Socialist Federative Republic of Yugoslavia in 1948. Angeli Radovani participates in two public competitions for monuments, which was a new theme in his sculptural oeuvre (a monument to the Croatian poet Silvije Strahimir Kranjčević and The Monument to the Uprising of the People of Drežnica [Spomenik ustanku naroda Drežnice], which won the second prize and was realized in the village of Drežnica in 1949). A new impetus for a shift in the manner of his expression arises during a study trip in 1950– 1951. He travels through Italy, France, Belgium, and Switzerland, studying the art of nonEuropean cultures, absorbing the power of their simple, cubic forms. This is the time when his formative period ends, and the phase of mature expression begins. He works and researches a lot to find his own expression. This leads him to refine his sculptural language and establish a new idea of sculpture that would surpass all previous symbolisms, classicisms, and academicisms. His first solo exhibition in 1952 was also the first solo exhibition of a sculptor after the Second World War. The free choice of the theme of representation (nude) and the way in which he stylized the nude and the portrait heralded changes. The exhibition arouses numerous reviews in the press as well as polemics. After the chapter in which the presence and reception of the mature and late oeuvre of Kosta Angeli Radovani was researched, the figural sculpture that gained its full expression in the mature period of his creation was also researched. He abandons idealization, narrativeness, and realism in the representation of the body, the representation is reduced, and the surface of the sculpture intentionally unpolished and unfinished, which evokes a tactile experience. On the surface, there are visible traces of shaping by fingers and palm, the signs of the sculptor's physical gesture. Anatomical arbitrariness is visible in the shaping of the elements of some sculptures. The sculptor does not shy away from deformations and ugliness in order to achieve an expressive, sometimes grotesque impression. The feet, hands, thighs, and buttocks are oversized, which points to the simplicity of "primitivist" forms. He draws inspiration from the creations of non-European cultures and from various archaisms. He increasingly applies stylization and the speech of the masses; the nudes are voluminous, and the need to investigate various sculptural problems results in the execution of numerous variations of the same theme. He is engaged in the research into various relations of compositional elements, such as figure and pedestal, the closedness and openness of the mass to space, the flatness and saliency of the volume of sculpture, the polishedness and roughness of surface, which in some works joins at sharp edges contrary to anatomical accuracy. In a special chapter, the sculptural cycle The Quince (Dunja; 19 variations, 1957–1986) is interpreted, with which he reaches the pinnacle of sculptural research, creating distinctive variants of a lush, mature female body. In some examples, he reduces certain parts of the body to round geometric bodies (cylinder, sphere), or stylizes them to the edge of abstraction. He never abandoned the recognition of the motif, which was his conscious choice. Until 1963 dominates the nude in standing position, but then the seated nude prevails, which intrigues him with immense possibilities of composing numerous variants while searching for a balance of elements. They are connected by the principle of building the mass from the core. He innovates the role of the pedestal, which he either abolishes or integrates into the sculptural solution (it is part of the cast, or he chooses a wooden stump, an iron rail, on which the figure is seated). By analyzing his mature sculptural oeuvre, we determined various formal and stylistic features in the manner of his shaping. In the nudes, we distinguish between three ways of modeling: round volumes and organic forms, then organic forms that he, in individual parts, cubizes and shapes with flat surfaces that are joined at sharp edges, and more radical modeling by decomposing round volumes through the process of geometrization and cubizing. The representation of female nude, as the dominant theme of the sculptor's work— viewed in the context of "primitivist" art—can also be interpreted as a symbol of natural cycles, the primordial, and the fertility. The commitment to depicting human figure stems from personal humanism, but also from the artistic climate that prevailed after the Second World War, and which, after the Holocaust and the era of the atomic bomb, aroused the interest of a group of artists while returning to the sources, the pre-cultural and the prerational. The portrait, which is the sculptor's second major theme, is explored in separate chapters. In addition to memorial portrait sculptures, he also modeled portraits of acquaintances and academicians, renowned personalities from Croatian culture, art, history, and science. He made portraits to order, but also on his own initiative, attracted by an interesting, unusual physiognomy or personality and achievements of the person he portrayed, and motivated by the desire to solve a new artistic problem. Already during his schooling he models portraits under the influence of academic realism and other influences. He gets rid of these influences with portraits created during the war, when he abandons description and idealization. After a short period of modeling portraits in the spirit of socialist realism, in the early 1950s comes a shift toward more modern expression. Important for finding his own expression was his knowledge of the portrait oeuvres of Marino Marini and Marcel Gimond. In the voluminous portrait oeuvre of Kosta Angeli Radovani, we determined the existence of two dominant stylistic and morphological approaches—in the first, the face is elongated, the surfaces follow the bones of the skull, and the surface of the face is furrowed with lines, with which he achieves expressiveness, while in the other approach, there is a reduction of descriptive elements to essential physiognomic features of the portrayed, the volumetric thickening, and a higher degree of geometric stylization, emphasized abstraction, and abandonment of psychologization. From this approach, with further stylization, he started to emphasize geometrization. He modeled some portraits in multiple versions, returning to them in various time periods as they were stimulating for him in his solving of certain sculptural problems. It is the shaping, which focuses on shaping phenomena and research of form—rather than on the similarity to the model—that the elements of modernism are most present. He strove to present the key physiognomic characteristics and the unique character of the portrayed in a synthetic manner and with reduced means. He created a unique gallery of portraits of unknown persons, but also of those working in the public, such as renowned art historians like Kruno Prijatelj, Ljubo Karaman, the archaeologist Grga Novak, academicians, musicians, directors, and other people from cultural, scientific, and public life. By choosing various physiognomies and characters, he went beyond the individual level, presenting a general, universal image of man. He also created a notable oeuvre of relief portraits in the medium of portrait medal. These are predominantly portraits of people from public, cultural, and scientific life, as well as academicians whom he was modeling from 1963 to 2000. He mostly adhered to the traditional circular shape of the portrait medal. The representation is on the obverse, while the reverse is empty. His most significant medal design achievement is the Rector's Chain (Rektorski lanac; 1969). For medals, he uses two modeling methods. In one group of works there is an emphasized geometric stylization and harder modeling, while in the other group, there is softer modeling, a greater degree of reduction and highlighting of the experience of a person's character, as well as organic forms. He is focused on a condensed representation of physiognomy and the transfer of the experience of the portrayed. He does not elevate it to a symbol, a sign, which is the case in the classic medal design approach, but freely interprets it. The excellence of the portrait is manifested in the use of minimal visual artistic elements with which he achieves maximum expression. In the consistent shaping of the portrait, we find his unique contribution to and significance in the corpus of Croatian medal production. We found that the elements of modernism are manifested in the terseness of representation and the reduction of details, as well as in the emphasized stylization. Special chapters are devoted to drawing and print, which, until now, have been a less wellknown and poorly analyzed part of his oeuvre. For Kosta Angeli Radovani, drawing was his favorite art technique. With the help of drawings, we can follow the development of his artistic thinking, as well as changes that occurred in various stages of his creation. He used drawing in a wide range of forms, from sketches, with which he developed his ideas for sculptures and the reflection of body in space, to drawing as an independent visual artistic discipline, a rounded work of art. At the same time, he uses various artistic possibilities of drawing by using line—as a legible trace of gesture and movement—as well as spots. He creates drawings that are characterized by lightness and refinement, but also by power that he achieves with a clean, strong line. He achieves a range of representations from flat—made with a clean line—to voluminous, which are created by shading with pencil, charcoal, watercolor, or some other visual art technique. In drawing, the representation experienced a greater degree of deformity than in sculpture, motivated by a greater need for experimentation, creative freedom, and the specific qualities of the visual art technique. In two drawings created in 1957, he reached the edge of abstraction by reducing the representation and by radical geometric stylization. With drawings he also created templates according to which to make prints. The most common motifs are portraits and nudes – from the intimacy of The Quince or female nudes in the artist's studio, to the vortex of eroticized bodies playing and dancing. In prints, the central motif is a group of figures with emphasized movements and gestures, while the most common themes of representation are the struggle for freedom and justice. Along with the line with which he describes the scene, he also uses pure colors for the representation of the background and the volume of figures. Modernist features can be found in the deformities and expressive lines used to create the representation, as well as in the terseness and stylization of the representation. Monumental solutions are a less well-known and, so far, an only partially analyzed segment of the sculptural oeuvre of Kosta Angeli Radovani. This research has shown that, as a creator or co-creator, he had sixteen realized and fifteen unrealized projects. A special group consists of portrait sculptures placed in public spaces or in interiors of public institutions, cultural, and school facilities. By analyzing the entire oeuvre, the typology of memorial sculpture was established. This comprises reliefs, memorial figures (solid sculpture), spatially and sculpturally complex memorial solutions, as well as portraits and busts of real persons. Realized and unrealized solutions are dealt with in separate chapters, and, within this broader division, solid sculpture, relief, and monumental portraits and busts created for public spaces constitute separate units. From his earliest memorial solutions, he collaborated with architects. The ratio of creative contribution of the sculptor and the architect depended on the character of work. In the case of more complex memorial solutions, the architect's part was more emphasized in the design of architectural elements, while the sculptor's contribution was more pronounced in the sculptural execution of relief. The involvement of the architect in the elaboration of the conceptual project shows a high degree of responsibility of the sculptor toward the intervention in public space, and the need for each segment of the planning and execution of the artwork to be at a high professional level. He created monuments dedicated to work, while one unrealized monument is dedicated to workers' self-management, which is a rarity among post-war monuments. In addition, in several executions he shows female figures, which is also found in a smaller number of postwar memorial solutions. In the realized monuments, we can see a stylistic and morphological range from realistic monumental figural works (Monument to the Uprising of the People of Drežnica [Spomenik ustanku naroda Drežnice; 1949]), reliefs with narrative representations, to monuments characterized by modernist features through the reduction of elements, geometric stylization, and cubic construction of volumes (Macedonian Woman [Makedonka, 1956–1961]; Monument to Vjekoslav Karas [Spomenik Vjekoslavu Karasu, 1974]). In the execution of reliefs with figural themes, he applies geometric stylization, and, in this area, also modernizes the representation of figures. The most significant and the only spatially and sculpturally complex memorial solution realized is the Memorial Park to the Shot (Spomenpark strijeljanih) at Šubićevac in Šibenik (1961–1984), which he realized in collaboration with Zdenko Kolacio. The modernistically refined geometrized architectural elements establish a symbolic relationship with the place of exec
Recipročni odnosi percipiranog stila poučavanja nastavnika s motivacijom i akademskim postignućem učenika
No full textTeaching styles are crucial in creating a motivating environment. However, processes through which teachers shape students’ motivational and academic outcomes have not been fully established, especially for the maladaptive motivational dynamics. Additionally, research has only recently considered that students may have an inverse role in shaping teachers’ style through agentic (dis)engagement. Thus, the aim of this study was to explore reciprocal relationships between agentic (dis)engagement, perceived teachers’ teaching style, motivation and academic achievement as proposed by the revised model of student engagement (Reeve, Cheon & H. Jang, 2020), for the brighter (adaptive) and the darker (maladaptive) motivational pathway. We conducted a two-wave longitudinal study within the project FreeCareerChoice funded by the Croatian Science Foundation (IP-2019-04-7537). We gathered self-reported data from 1213 high school students (61.1% female, 53.9% vocational students). We utilised autoregressive cross-lagged modeling to determine the directional relationships between the variables. Our findings support the revised model of student engagement for the brighter pathway since most associations follow the model’s assumptions. However, we found that instead of agentic engagement, autonomous motivation is reciprocally associated with perceived teacher autonomy support. In terms of the darker motivational pathway, our results provide no support for the model, as no significant associations between the variables were found. The findings of the study significantly contribute to the understanding of teacher-student dynamics, as the revised model of student engagement has previously not been comprehensively tested. Additionally, the study yielded important practical implications as it highlights the need to encourage teachers to adopt an autonomy-supportive style.Uvod
U području obrazovne psihologije postoji slaganje da je pristup nastavnika učeniku ključan za motivacijske i akademske ishode učenika (Bureau i sur., 2021). Međutim, određeni aspekti dinamike odnosa nastavnika i učenika nisu temeljito istraženi. Ovo istraživanje će, stoga, doprinijeti novim spoznajama sveobuhvatnim ispitivanjem adaptivnih i neadaptivnih odnosa nastavnika i učenika u okviru teorije samodeterminacije (Deci i Ryan, 1985).
Teorija samodeterminacije opsežni je okvir za istraživanje motivacijskih procesa. Osnovna pretpostavka jedne od njezinih mini-teorija je da ljudi imaju tri urođene i univerzalne osnovne psihološke potrebe – potrebu za autonomijom, kompetentnosti i povezanosti (Deci i sur., 1991). Zadovoljenje potrebe, a osobito potrebe za autonomijom, potiče dobrobit i prosperitet, stoga se ljudi okreću okolinama u kojima ih mogu zadovoljiti (Vansteenkiste i sur., 2022). S druge strane, mogu se naći u okolinama koje frustriraju njihove potrebe, to jest aktivno ih sprječavaju u zadovoljenju potreba, što dovodi do smanjenje dobrobiti (Vansteenkiste i Ryan, 2013).
Pretpostavke teorije samodeterminacije o osnovnim psihološkim potrebama pokazale su se točnima u različitim domenama života (Ryan i sur., 2022). Osobit interes za istraživanja psiholoških potreba postoji u području obrazovanja s obzirom na centralnu ulogu koje obrazovanje ima u razvoju pojedinca (Ryan i Deci, 2020). Kad govorimo o obrazovanju, najznačajnije djelovanje u ostvarivanju psiholoških potreba ima nastavnik, to jest njegov stil poučavanja (Cheon i sur., 2016; Howard i sur., 2024; Núñez i León, 2018; Schuitema i sur., 2016). Možemo razlikovati dva osnovna stila poučavanja: nastavničku podršku autonomiji i nastavničku kontrolu. Nastavnička podrška autonomiji odnosi se na stil u kojem nastavnik uzima u obzir želje i potrebe učenika te se trudi zauzeti njihovu perspektivu (Aelterman i sur., 2019; Ryan i Deci, 2020). S druge strane nastavnička kontrola opisuje stil u kojem nastavnik prioritizira svoje ciljeve te ih nameće učenicima (Aelterman i sur., 2019). Iako ih se često tako predstavlja, ova dva stila nisu suprotstavljeni polovi iste dimenzije, već dva pristupa koja mogu koegzistirati (Aelterman i sur., 2019; Patall i sur., 2018). U prilog ovakvom pogledu na nastavničke stilove idu nalazi koji pokazuju relativno niske korelacije između njihovih razina, te istraživanja koja pokazuju da imaju drugačije ishode (Haerens i sur., 2015; H. Jang i sur., 2016; Reeve i sur., 2023; Reeve i Cheon, 2021; Vansteenkiste i Ryan, 2013). Naime, pokazuje se da nastavnička podrška autonomiji snažno pozitivno predviđa zadovoljenje psiholoških potreba i pozitivne učeničke ishode, dok nije povezana ili je slabo negativno povezana s frustracijom potreba i negativnim učeničkim ishodima (Bartholomew, Ntoumanis, Ryan, Bosch, i Thøgersen-Ntoumani, 2011; H. Jang i sur., 2016; Reeve i Cheon, 2021; Vansteenkiste i Ryan, 2013). Za nastavničku kontrolu vrijedi suprotno. Ova konceptualizacija koja odvaja svjetliji motivacijski put koji povezuje nastavničku podršku autonomiji i pozitivne učeničke ishode, te mračniji motivacijski put koji povezuje nastavničku kontrolu i negativne učeničke ishode, naziva se dvoprocesni model motivacije. Iako su oba puta podjednako važna za razumijevanje motiviranog ponašanja, mračniji motivacijski put značajno je manje istražen u svim domenama, pa tako i obrazovanju (Bartholomew i sur., 2018; Bartholomew, Ntoumanis, Ryan, Bosch, i Thøgersen-Ntoumani, 2011; De Meyer i sur., 2014; H. Jang i sur., 2016; Li i sur., 2018; Reeve, Cheon i H. Jang, 2020; S. A. Zhou i sur., 2023).
U kontekstu teorije samodeterminacije, motivacija uključuje dvije grupe motivacija. Autonomna motivacija se odnosi na samodeterminirane oblike motivacije, to jest na motivaciju u kojoj se pojedinac samostalno upušta u ponašanje zbog osobne važnosti tog ponašanja ili jer u njemu uživa (Ryan i Deci, 2020). U školskom kontekstu, autonomno su motivirani oni učenici koji uče jer smatraju da je učiti važno ili ih učenje interesira. S druge strane imamo kontroliranu motivaciju – motivaciju koja proizlazi iz unutarnje ili vanjske prisile (Ryan i Deci, 2020). Primjerice, kontrolirano su motivirani oni učenici koji uče zbog nagrada i kazni ili zbog krivnje i samopotvrđivanja. U skladu s dvoprocesnim modelom motivacije, autonomna motivacija bi trebala pripadati na svjetliji motivacijski put kao ishod nastavničke podrške autonomije, dok bi kontrolirana motivacija trebala pripadati na mračniji motivacijski put kao ishod nastavničke kontrole. Prijašnja istraživanja podržavaju takvu podjelu (André i sur., 2023; Haerens i sur., 2015; Patall i sur., 2018; Rodrigues i sur., 2019), no pregled literature pokazao je da je motivacija kao konstrukt relativno malo istraživana u okviru dvoprocesnih modela motivacije.
Jedan od ključnih ishoda učeničke motivacije je uključenost u nastavu. Iako se tradicionalno dijeli na tri komponente – emocionalnu, kognitivnu i bihevioralnu, Reeve i Tseng (2011) dodaju četvrtu komponentu – proaktivnu uključenost. Proaktivna uključenost odnosi se na konstruktivni doprinos učenika nastavi, to jest njihovo postavljanje pitanja, davanje povratne informacije i izražavanje potreba u nastavnom procesu (Reeve, 2013; Reeve i Tseng, 2011). Proaktivna uključenost, s jedne strane, kao i ostale komponente uključenosti, doprinosi akademskom postignuću učenika (Reeve, 2013; Reeve, Cheon i H. Jang, 2020; Reeve i sur., 2022; Reeve i Tseng, 2011; Skinner i Pitzer, 2012). S druge strane, za razliku od ostalih komponenti uključenosti, služi kao signal nastavniku kako da nastavu učini primjerenijom potrebama učenika (Reeve i sur., 2022; Reeve i Shin, 2020; Reeve i Tseng, 2011). Dakle, proaktivna uključenost trebala bi biti recipročno povezana s nastavničkom podrškom autonomiji na svjetlijem motivacijskom putu. Iako istraživanja idu u prilog postojanju ove veze (H. Jang i sur., 2012; 2016; H.-R. Jang et al., 2024; Matos i sur., 2018; Patall i sur., 2019; Reeve, 2013), potrebno ju je dodatno istražiti s obzirom na metodološke nedostatke prijašnjih istraživanja (Patall i sur., 2018; 2019; Reeve i Shin, 2020). Još jedan konstrukt koji nije dovoljno istraživan je proaktivna neuključenost. Ona opisuje učenike koji pasivno prihvaćaju tijek nastavnog sata, bez pokušaja da gradivo i način predavanja pokušaju prilagoditi svojim potrebama (Reeve i Shin, 2020). Slično kao podrška autonomiji u odnosu na kontrolu i autonomna u odnosu na kontroliranu motivaciju, proaktivna neuključenost predstavlja pandan proaktivne uključenost na mračnijem motivacijskom putu (H. Jang i sur., 2016; Reeve i Cheon, 2021; Reeve i Tseng, 2011). Prema tome, možemo očekivati da je proaktivna neuključenost rezultat nastavničke kontrole i kontrolirane motivacije te da predviđa lošije akademsko postignuće. Također, trebala bi recipročno predviđati porast nastavničke kontrole, s obzirom da nastavnici od učenika koji ne participiraju ne dobivaju povratnu informaciju kako im prilagoditi nastavu (H.-R. Jang i sur., 2024; Patall, 2024; Reeve, Cheon i Yu, 2020). Iako postoje pretpostavke o ulozi proaktivne neuključenosti, ona je u literaturi većinski zanemarena, stoga su nužna daljnja istraživanja (H. Jang i sur., 2016; Reeve, Cheon i Yu, 2020).
Pregled literature u području pokazao je snažnu podršku za dvoprocesne modele motivacije, s tim da su konstrukti koji pripadaju svjetlijem motivacijskom putu značajno istraženiji od onih koji pripadaju mračnijem motivacijskom putu. Iako je relativno jasno da postoje dva motivacijska puta, procesi kroz koji nastavnici potiču motivaciju i akademsko postignuće učenika još uvijek nisu potpuno jasni. Također, pokazuje se da su istraživanja tek odnedavno motivacijski proces počela promatrati kao dvosmjeran – nastavnici motiviraju učenike, a učenici motiviraju nastavnike. Iz tog razloga, važno je istraživati proaktivnu uključenost i neuključenost, s obzirom da se radi o relativno novim konstruktima čija povratna veza s nastavničkim stilovima nije u potpunosti razjašnjena. Dakle, možemo reći da u ovom području postoje dva ključna pitanja (Reeve i Cheon, 2021): (1) Kroz koje procese nastavnici utječu na motivacijske i akademske ishode učenika? i (2) Mogu li učenici zauzvrat utjecati na stil poučavanja svojih nastavnika?
Teorijski model koji odgovara na ova dva pitanja te povezuje prije opisane konstrukte je revidirani model uključenosti učenika (Reeve, Cheon i H. Jang, 2020). Prema modelu, nastavnička podrška autonomiji predviđa autonomnu motivaciju učenika, koja je zatim povezana s proaktivnom uključenošću učenika. Ako se nastavnik trudi više uključiti potrebe učenika u nastavu, oni će biti zainteresiraniji te je smatrati važnijom (Reeve i Cheon, 2021). Posljedično, učenici će biti motiviraniji više saznati i sudjelovati na nastavi (Reeve i sur., 2004; Skinner i Pitzer, 2012; Stroet i sur., 2013). Povećana razina proaktivne uključenosti, po modelu, zatim previđa akademsko postignuće učenika te buduću nastavničku podršku autonomiji. S obzirom da učenici postavljaju pitanja i daju sugestije, bolje će shvatiti nastavno gradivo te će nastavnika uputiti kako da im dodatno prilagodi nastavu (Reeve, 2013; Reeve i Tseng, 2011). Kao što je vidljivo iz opisanog, revidirani model učeničke uključenosti opisuje odnose varijabli svjetlijeg, no ne i mračnijeg motivacijskog puta. Iz tog razloga Reeve, Cheon i H. Jang (2020) u radu u kojem su definirali ovaj model preporučuju njegovu prilagodbu za mračniji motivacijski put. Iz tog razloga, predložili smo model koji translatira odnose opisane u revidiranom modelu učeničke uključenosti s varijablama s mračnijeg motivacijskog puta. Prema tome, nastavnička kontrola bi trebala predviđati kontroliranu motivaciju koja je zatim povezana s proaktivnom neuključenosti. Ako nastavnici stvaraju pritisak na učenike, taj pritisak će im postati glavni razlog za učenje te stoga učenici neće imati želju aktivnije sudjelovati u nastavi (Bartholomew i sur., 2018; Curran i Standage, 2017; Vansteenkiste i Ryan, 2013). Proaktivna neuključenost učenika zatim će rezultirati slabijim akademskim postignućem i budućom kontrolom nastavnika. Ako učenici ne traže dodatna objašnjenja lošije će savladati gradivo te neće razjasniti nastavniku na koji način bi im bolje mogao približiti gradivo (Bartholomew i sur., 2018; Reeve, Cheon i Yu, 2020).
Iako za revidirani model učeničke uključenosti postoji jasna teorijska te nešto empirijske podrške, neki autori sugeriraju da su motivacijski procesi složeniji od onog opisanog u modelu (H. Jang i sur., 2012). Naime, smatraju kako bi model trebao uključivati dodatne recipročne veze (H.-R. Jang, 2023; Patall, 2024; Patall i sur., 2019; Reeve i sur., 2022). Primjerice, da bi akademsko postignuće učenika također mogao poticati nastavnike da daju više autonomije učenicima, a učenike dodatno motivirati za učenje. Iz tog razloga, potrebna je cjelovita provjera pretpostavki revidiranog modela učeničke uključenosti, kako bi se utvrdilo temporalne i recipročne veze između proaktivne (ne)uključenosti, stila poučavanja nastavnika, akademske motivacije i akademskog postignuća. Budući da je većina prijašnjih istraživanja imala transverzalni nacrt (npr. Behzadnia i sur., 2018; Collie i sur.., 2019; Gutiérrez i Tomás, 2019; Haerens i sur., 2015; H. Jang i sur., 2009; Johansen i sur., 2023; Mameli i Passini, 2017), to nije omogućavalo provjeru takvih odnosa. Naše istraživanje, stoga, predstavlja vrijedan doprinos spoznajama u području. Također, većina prije provedenih kvalitetnih istraživanja o ovoj temi koristila je uzorke iz Jugoistočne Azije te se fokusirala isključivo na nastavu tjelesnog odgoja. Iz tog razloga, naše će istraživanje, koje je smješteno u Zapadni kontekst te koristi globalne mjere, umjesto mjera usmjerenih na specifičan školski predmet, doprinijeti potvrđivanju zaključaka prijašnjih istraživanja u drugačijem kontekstu.
Cilj i problemi istraživanja
Cilj istraživanja bio je ispitati recipročne odnose između proaktivne (ne)uključenosti, percipiranog stila poučavanja nastavnika, akademske motivacije i akademskog postignuća učenika prema pretpostavkama modela Reevea, Cheona i H. Jang (2020), u kontekstima svjetlijeg i mračnijeg motivacijskog puta. Ovaj je cilj ispitan kroz četiri istraživačka problema: (1) Predviđaju li se percipirana nastavnička podrška autonomiji te autonomna motivacija, proaktivna uključenost i akademsko postignuće učenika međusobno uzastopnim redoslijedom?, (2) Postoji li recipročna povezanost između percipirane nastavničke podrške autonomiji i proaktivne uključenosti?, (3) Predviđaju li se percipirana nastavnička kontrola te kontrolirana motivacija, proaktivna neuključenost i akademsko postignuće učenika međusobno uzastopnim redoslijedom? i (4) Postoji li recipročna povezanost između percipirana nastavničke kontrole i proaktivne neuključenosti učenika?
Metoda
Ovo istraživanje je provedeno u sklopu šireg projekta FreeCareerChoice koji financira Hrvatska zaklada za znanost (IP-2019-04-7537). Nacrt istraživanja je longitudinalan, s dva vala prikupljanja podataka. Vremenske točke u kojima su podaci prikupljeni razmaknuti su oko godinu dana.
Sudionici
U istraživanju je sudjelovalo 1213 učenika srednjih škola iz cijele Hrvatske (61.1% djevojke, 53.9% učenici strukovnih škola). Učenici su polazili 18 škola, to jest 67 različitih razreda. Prosječna dob u prvoj točci prikupljanja podataka bila je 16.47 godina (SD = 0.64).
Postupak
Prije početka istraživanja, dobivena je privola Etičkog povjerenstva Instituta društvenih znanosti Ivo Pilar za cijeli projekt (no. 11-73/19-1261), te Etičkog povjerenstva Odsjeka za psihologiju Filozofskog fakulteta Sveučilišta u Zagrebu za ovo istraživanje (EPOP_2022_23_29). Prije sudjelovanja učenika u prvom valu istraživanja pisanu suglasnost za sudjelovanje su dali njihovi roditelji, dok su učenici prije početka ispitivanja u svakom valu dali svoju suglasnost za sudjelovanje. Prikupljanje podataka bilo je organizirano u školama tijekom nastave u trajanju od oko 40 minuta. Ispitivanje je provedeno putem online platforme kojoj su učenici pristupali putem školskih računala. Tijekom ispitivanja bio je prisutan član projektnog tima ili stručni suradnik koji je prethodno upoznat sa sadržajem upitnika.
Instrumenti
U istraživanju su korištene mjere samoprocjene na globalnoj razini, dakle procjene učenika o nastavnicima i sebi općenito, a ne o specifičnom predmetu. Mjerili smo percipirani nastavnički stil koji podržava autonomiju, percipirani nastavnički kontrolirajući stil, akademsku motivaciju, proaktivnu uključenost, proaktivnu neuključenost te prikupili podatke o završnom prosjeku ocjena učenika i njihovim sociodemografskim karakteristikama. Svi instrumenti su prethodno validirani, ali je većina bila po prvi bila prevedena na hrvatski jezik metodom prijevod-nazad prijevod (Brislin, 1970). Rezultati predistraživanja i psihometrijska analiza instrumenata pokazali su da imaju očekivanu strukturu i visoku pouzdanost.
Analitička strategija
Analiza podataka napravljena je u programima IBM SPSS Statistics 26.0 (IBM Corp, 2019) i R verzija 4.4.0. (R Core Team, 2024). Provedena je u četiri koraka: (1) analiza nedostajućih podataka i osipanja, (2) deskriptivna analiza, (3) analiza longitudinalne invarijantnosti, te (4) glavna analiza. U glavnoj analizi smo koristili autoregresijske križne modele. Specifično, usporedili smo četiri modela kako bismo utvrdili koji najbolje opisuje podatke: (1) model stabilnosti (specificirane samo autoregresivne veze), (2) model kauzalnosti (specificirane veze definirane u skladu s teorijskim modelom), (3) model obrnute kauzalnosti (specificirane veze definirane suprotno teorijskom modelu), (4) recipročni model (specificirane sve autoregresivne i križne veze). U glavnoj analizi kontrolirali smo obrazovni program, kohortu i rod učenika.
Rezultati i rasprava
Prva dva istraživačka problema odnosila su se na svjetliji motivacijski put. Analiza autoregresijskih križnih modela pokazala je da je najprimjereniji model recipročni model. To nam to ukazuje da je potrebno specificiranje drugačijih ili dodatnih puteva u odnosu na revidirani model uključenosti učenika (Reeve, Cheon i H. Jang, 2020). Ipak da bi se utvrdilo u kojoj mjeri dobiveni model odstupa od teorijskog potrebno ga je pobliže analizirati.
Da bismo to učinili, prvo smo pogledali povezanosti koje objašnjavaju proces kroz koji nastavnik mijenja motivacijske i akademske ishode učenika. Sukladno našim hipotezama pokazalo se da T1 percipirana nastavnička podrška autonomiji predviđa T2 autonomnu motivaciju učenika, T1 autonomna motivacija predviđa T2 proaktivnu uključenost, a T1 proaktivna uključenost T2 akademsku uspješnost. Ovakve veze su u skladu s pretpostavkama revidiranog modela učeničke uključenosti (Reeve, Cheon i H. Jang, 2020), to jest konzistentne su sa sukcesivnim procesom kroz koji nastavnik djeluje na učenike prema modelu. Iako model pretpostavlja recipročnu vezu između proaktivne uključenosti i nastavničke podrške autonomiji, nije pronađena korelacija između T1 proaktivne uključenosti i T2 percipirane nastavničke podrške autonomiji, čime nismo potvrdili svoju hipotezu. Neka prijašnja istraživanja također nisu pronašla ovu recipročnu vezu (H. Jang i sur., 2016; Patall, 2024; S. A. Zhou i sur., 2023). Oslanjajući se na njihove nalaze pretpostavili smo tri razloga zbog kojih veza nije nađena u našem istraživanju. Prvo, moguće je, ali ne vjerojatno, da smo u uzorku zahvatili povećani broj učenika iz marginaliziranih skupina ili skupina koje imaju slabije akademsko postignuće. Učenici iz takvih skupina imaju manju mogućnost utjecati na svoje nastavnike, to jest njihova proaktivna uključenost često ne rezultira time da im nastavnici daju više autonomije (Liu i sur., 2024; Zambrano i sur., 2021). Drugo, moguće je da konceptualizacija i mjere proaktivne uključenosti nisu prilagođene za zapadni kontekst. Istraživanja provedena u SAD-u i Europi pokazuju da učenici smatraju da proaktivna uključenost također treba uključivati kolaborativna ponašanja, uključenost izvan nastave i elemente samoreguliranog učenja (Mameli i Passini, 2018; Petričević i sur., 2024; Rovan, 2024; Zambrano i sur., 2022). Posljedično, moguće je da ovim istraživanjem nismo adekvatno zahvatili proaktivnu uključenost. Treće, moguće je da nastavnici imaju raznolike reakcije na proaktivnu uključenost učenika. Dok dio njih, u skladu s teorijom, vjerojatno vidi proaktivnu uključenost učenika kao korisnu povratnu informaciju, drugi dio vjerojatno reagira antagonistički (Matos i sur., 2018; Patall i sur., 2019). Iz tog razloga, moguće je da polovica nastavnika više podupire autonomiju kad su učenici proaktivni, dok drugi umanjuju svoju podršku s obzirom na negativnu percepciju učeničkih primjedbi, što na kraju rezultira nultom povezanošću proaktivne uključenosti i percipirane podrške autonomiji nastavnika. Iako nismo našli povezanost proaktivne uključenosti i percipirane podrške autonomiji nastavnika, utvrđena je recipročna veza između T1 autonomne motivacije i T2 percipirane nastavničke podrške autonomiji. Neki autori smatraju da autonomna motivacija može služiti kao signal nastavnicima da postanu više podržavajući (H.-R. Jang, 2023; Patall i sur., 2019), no mehanizmi u pozadini ove povezanosti nisu u potpunosti jasni s obzirom da istraživanja pokazuju da je nastavnicima teško percipirati učeničku motivaciju koja je unutarnja (Lee i Reeve, 2012). Iz tog razloga smo spekulirali da je nađena povezanost rezultat korištenja isključivo mjera samoprocjene. Kad su učenici više autonomno motivirani, ne dolazi do stvarnih promjena u ponašanju njihovih nastavnika, već učenici percipiraju svoje nastavnike u pozitivnijem svjetlu (Schuitema i sur., 2016). Ukratko, pretpostavljamo da se ne radi se o stvarnoj povezanosti između konstrukata nego o metodološkom artefaktu.
Druga dva istraživačka pitanja odnosila su se na mračniji motivacijsk
Development of a numerical model of water flow through the unsaturated zone of the Zagreb aquifer in the area of Velika Gorica wellfield : doctoral thesis
No full textOdrživo korištenje i upravljanje zagrebačkog vodonosnika kao strateškog resursa Republike Hrvatske, između ostalog, zahtijeva i identifikaciju i kvantifikaciju svih izvora njegovog prihranjivanja. U cilju kvantifikacije prihranjivanja vodonosnika iz oborine, kao jednog od izvora prihranjivanja, izrađeno je nekoliko je numeričkih dvodimenzionalnih modela tečenja vode i trasiranja čestica kroz nesaturiranu zonu zagrebačkog vodonosnika na području vodocrpilišta Velika Gorica. Pri definiranju geometrije, parametara, početnih i rubnih uvjeta, te za kalibraciju modela korišteni su podaci prikupljeni na istraživačkom poligonu koji se nalazi u prvoj zoni sanitarne zaštite zdenca B-1 vodocrpilišta. Na poligonu se kontinuirano mjere parametri nesaturirane zone pomoću TDR (engl. Time Domain Reflectometry) sondi te meteorološki uvjeti, a izvedena su i geofizička istraživanja te nekoliko eksperimenata trasiranja. Rezultati prognoznog modela za razdoblje od 8. 11. 2019. do 8. 5. 2023. utvrdili su količinu prihranjivanja vodonosnika iz oborine od 16 % i brzinu procjeđivanja oborine od tri godine i tri mjeseca, od trenutka infiltracije na površini terena do razine podzemne vode. Prognoznim modelom za buduće razdoblje (2019. - 2040.) predviđena je dvostruko veća količina procjeđivanja od 36 % što je u skladu s povećanjem učestalosti oborine u razdoblju do 2040. godine. Veća učestalost oborine uzrokovala je i kraće vrijeme procjeđivanja oborine, odnosno godinu dana i četiri mjeseca. Modelima tečenja, kontinuiranim mjerenjima parametara nesaturirane zone na istraživačkom poligonu i eksperimentima trasiranja utvrđeni su faktori koji utječu na količine i brzine procjeđivanja vode u nesaturiranoj zoni: učestalost, količina i intenzitet oborine, sadržaji vode u nesaturiranoj zoni neposredno prije oborinskog događaja, zatim heterogenost naslaga te pojava preferencijalnog tečenja. Pouzdano definiranje rubnog uvjeta infiltracije vode iz oborine do podzemne vode omogućava unaprjeđenje regionalnih numeričkih modela tečenja podzemne vode, a model tečenja vode kroz nesaturiranu zonu temelj je za buduće modele pronosa onečišćenja s površine do podzemne vode.Sustainable management of the Zagreb aquifer, as a strategic resource of the Republic of Croatia, requires identifying and quantifying all sources of its recharge. In order to identify and quantify the recharge from precipitation, as one of the sources of recharge, a numerical two-dimensional model of water flow through the unsaturated zone was built in the area of the Velika Gorica wellfield. A research polygon, consisting of a meteorological station and a shaft, has been established at the Velika Gorica wellfield, where the parameters of the unsaturated zone are continuously measured at different depths using TDR (Time Domain Reflectometry) probes. Geophysical measurements were performed on the surface next to the shaft itself, and the method was electrical resistivity tomography. The measurements performed at the research polygon were used to define the unsaturated flow model geometry, parameters, initial and boundary conditions, and also for model calibration. The results of the flow model for the period from 11/8/2019 to 5/8/2023 pointed out that the precipitation contributes to aquifer recharge by 16 % amount in average. However, that amount varies greatly from year to year. For example, in the one-year periods from 11/8/2019 to 11/8/2020 and from 11/8/2020 to 11/8/2021, the aquifer recharge from precipitation amounts 20 and 19 %, while in the period from 11/8/2021 to 11/8/2022, that percentage is only 2%. The small amount of aquifer recharge from precipitation in 2022 is the result of relatively longer previous dry periods. In 2020, 17% less precipitation occurred than the multi-year average, in 2021 26% less, and in 2022 even 30% less. On top of that, 2022 was an above-average dry year. The most significant amounts aquifer recharge from precipitation occurs at the end and beginning of the year, that is, from December to April, depending on the hydrological year. The periods of significant aquifer recharge from precipitation coincide with the periods of high groundwater levels, high water contents in the unsaturated zone and low values of evapotranspiration. The results of the particle tracking model for the period from 11/8/2019 to 5/8/2023 showed a relatively long travel time of precipitation from the infiltration moment on the ground surface to the moment it reaches the groundwater, i.e., 3 years and 3 months. The factor that most affects the rather slow percolation of precipitation is dry hydrological conditions, that is, below-average amounts of precipitation and their unfavorable distribution (a small number of hours with precipitation). Other factors that affect precipitation percolation and cannot be ignored considering the research location are the heterogeneity of the observed unsaturated zone profile the appearance of preferential flow. The water flow forecast model for the future period (2019 – 2040) predicts a 36 % as the amount of aquifers recharge from precipitation, which is twice as much as the amount simulated by the model for the period from 11/8/2019 to 5/8/2023, which is in accordance with the predicted increase of the precipitation frequency in the future climate. Accordingly, particle tracking model simulated a much shorter travel time of precipitation through the unsaturated zone, i.e. 1 year and 4 months. Unsaturated flow models, continuous measurements of parameters of the unsaturated zone, as well as tracer experiments, showed that the amount of aquifer recharge from precipitation and the travel time of precipitation in the unsaturated zone from the ground surface to the groundwater is affected by the frequency, amount and intensity of precipitation, the water contents in the unsaturated zone before the precipitation event, then the heterogeneity of the observed unsaturated deposit and the appearance of preferential flow. Knowledge of the amounts and rates of precipitation and also of the percolation precipitation process through the unsaturated zone enables the quantification of aquifer recharge from precipitation, which further enables the improvement of regional groundwater flow models, by reliable definition of the boundary condition represented by aquifer recharge from precipitation. Additionally, the unsaturated flow model represents the basis for future models of contaminant transport through the unsaturated zone
ULOGA de novo METILACIJE DNA U ODGOVORU BILJAKA NA POVIŠENU TEMPERATURU
No full textOne of the key factors affecting plant survival and agricultural yield production is temperature. In this thesis, effects of prolonged 37 °C and short-term 45 °C heat treatments were investigated in Arabidopsis thaliana, Brassica rapa ssp. pekinensis and Solanum lycopersicum. Elevated temperatures negatively affected germination, development, shoot and root growth, and flower morphology. Seedlings and inflorescences were more thermosensitive than leaves of adult plants. Global DNA methylation levels and expression of key RNA-directed DNA methylation (RdDM) genes varied in different species, tissues and under heat stress. To evaluate the role of de novo DNA methylation in heat stress, different A. thaliana lines with altered RdDM pathway were used. DNA methylation at single-base resolution in AGL14, FBW2 and RKP genes and expression of RdDM-related genes revealed differences under heat stress, indicating the importance of an intact de novo DNA methylation machinery in thermotolerance.Temperatura je jedan od ključnih čimbenika koji utječu na preživljavanje biljaka i poljoprivredne prinose. U ovom doktorskom radu istražen je utjecaj dugotrajnog izlaganja biljaka Arabidopsis thaliana, Brassica rapa ssp. pekinensis i Solanum lycopersicum temperaturi od 37 °C i kratkotrajnog izlaganja na 45 °C. Povišene su temperature negativno utjecale na klijavost, razvoj, rast izdanaka i korijena te morfologiju cvijeta. Klijanci i cvatovi bili su osjetljiviji na toplinski stres od listova odraslih biljaka. Globalne razine metilacije DNA i ekspresija ključnih gena uključenih u metilaciju DNA posredovanu malim RNA molekulama (RdDM) varirala je u različitim vrstama i tkivima te nakon izlaganja toplinskom stresu. Za procjenu uloge de novo metilacije DNA u toplinskom stresu korištene su različite linije A. thaliana u kojima je promijenjen put RdDM. Promjene u metilaciji gena AGL14, FBW2 i RKP te ekspresiji gena uključenih u RdDM uzrokovane toplinskim stresom ukazuju na važnost intaktnog de novo mehanizma metilacije DNA u toleranciji na povišenu temperaturu
Razvoj TiO2-nanokompozitnih fotokatalizatora za dobivanje vodika pod djelovanjem Sunčeva zračenja
No full textToday's economic situation and market uncertainty warn of the instability of using fossil fuels and promoting the production of alternative fuels, such as hydrogen, using renewable sources. One of the extremely interesting processes that are under continuous scientific development and improvement for further application is Solar-driven photocatalytic hydrogen production. Most of the photocatalytic studies involve the use of titanium dioxide (TiO2) as photocatalytic material. However, its wider application requires harvesting of a broader spectrum of Solar irradiation and suppression of the recombination of photogenerated charge carriers. These limitations can be overcome by the use of different strategies, among which the focus is put on the creation of heterojunctions with another narrow bandgap semiconductor which can provide high response in the visible light region, as well as carbon-based materials that can enhance charge transfer efficiency. For that purpose, in the doctoral dissertation, two groups of photocatalytically active composite materials were synthesized and their photocatalytic activity towards Solar-driven hydrogen production was examined and compared. The first group included TiO2 – tin disulphide(SnS2) / reduced graphene oxide (RGO) ternary composite materials with different wt.% of SnS2 (5 wt.% and 10 wt.%) and RGO wt.% (0.01-0.1 wt.%), while the second group consisted of TiO2 and RGO binary composite with variable RGO mass ratios (0.01 – 5 wt.%). Before testing the activity, a comprehensive and detailed morphological, structural, optical and photoelectrochemical characterization of the obtained materials was performed. Photocatalytic hydrogen production experiments were conducted in a 20 vol.% triethanolamine (TEOA) solution under a 450 W xenon lamp mimicking Solar irradiation. As far as the first group of materials are concerned, the results revealed that the sample TiO2 – SnS2 (5 wt.%) / RGO (0.01 wt.%), labelled as TSGR1, exhibited the highest hydrogen generation rate of 61.5 μmol/h/g, as well as relatively high photostability during three consecutive cycles of testing. Photocatalytic tests have shown that a smaller mass ratio of SnS2 up to 5 wt.%, as well as a minimal mass ratio of RGO up to 0.01 wt.%, favors higher hydrogen generation. In the second group of materials, photocatalytic experiments have showed that even low mass ratios of RGO component (below 1 wt.%) can have a great influence on the photocatalytic activity and properties of the obtained material. The composite with 0.05 RGO wt.% achieved the highest H2 generation rate of 139 μmol/h/g and maintained high photostability. The incorporation of RGO into the TiO2 matrix enhanced efficient charge separation, reduced the energy bandgap (Eg), and thus increased the visible light response, leading to more effective hydrogen production. The examination of both material groups showed that partial reduction of the precursor solution of GO to RGO took place during the solvothermal synthesis at the elevated pressure and temperature conditions. Furthermore, this research has proven that very low mass ratios of RGO can significantly enhance photocatalytic activity and material properties. In contrast, higher RGO content in both cases negatively impacted H2 production, likely because higher RGO material incorporation into the composite affects the blocking of the photocatalytic specific surface and prevents the intrusion of Solar irradiation necessary for the activation of the material.Današnja gospodarska situacija i tržišna nesigurnost upozoravaju na nestabilnost korištenja fosilnih goriva i promicanja proizvodnje alternativnih goriva, poput vodika, iz obnovljivih izvora. Jedan od iznimno zanimljivih procesa koji se kontinuirano znanstveno razvija i usavršava za daljnju primjenu je solarna fotokatalitička proizvodnja vodika. Većina fotokatalitičkih studija uključuje korištenje titanijevog dioksida (TiO2) kao glavnog fotokatalitičkog materijala. Međutim, njegova šira primjena zahtijeva prikupljanje šireg spektra Sunčevog zračenja i suzbijanje rekombinacije fotogeneriranih naboja. Ta se ograničenja mogu prevladati uporabom različitih strategija, među kojima je najznačajnije kompozitiranje TiO2 s ostalim poluvodičkim materijalima s visokim odzivom u području vidljive svjetlosti, kao i materijalima na bazi ugljika koji utječu na povećanje elektronske vodljivosti između materijala. S tim ciljem, u sklopu doktorske disertacije sintetizirane su dvije skupine fotokatalitički aktivnih kompozitnih materijala te je ispitana njihova fotokatalitička aktivnost prema proizvodnji vodika djelovanjem Sunčeva zračenja. Prva skupina uključuje ternarni kompozitni materijal, TiO2 – kositrov disulfid (SnS2) / reducirani grafen oksid (RGO), s različitim masenim udjelima (w) SnS2 ( w = 5 i 10 %) i RGO (w = 0,01 – 0,01 %) u kompozitu. Drugu skupinu uključuje pak binarni kompozitni materijal, TiO2 – RGO, s različitim masenim udjelima RGO-a (w = 0,01 – 5 %). Prije testiranja fotokatalitičke aktivnosti, provedena je detaljna morfološka, strukturna, optička i fotoelektrokemijska karakterizacija sintetiziranih materijala. Eksperimenti fotokatalitičke proizvodnje vodika provedeni su u 20 vol.% vodenoj otopini trietanolamina (TEOA) pod djelovanjem ksenonske lampe jačine 450 W koja emitira zračenje ekvivalentno Sunčevom zračenju. Što se tiče prve skupine materijala, rezultati su pokazali da je uzorak TiO2 – SnS2 (w = 5 %) / RGO (w = 0,01 %), označen kao TSGR1, pokazao najveću stopu proizvodnje vodika u iznosu od 61,5 μmol/h/g, kao i relativno visoku fotostabilnost tijekom tri uzastopna ciklusa ispitivanja. Fotokatalitički testovi pokazali su da manji maseni udjeli SnS2 do 5 %, kao i minimalni maseni udio RGO od 0,01 %, pogoduju stvaranju većih količina vodika. U drugoj su skupini materijala fotokatalitički eksperimenti pokazali da čak i niski maseni udjeli RGO komponente (w ≤ 1 %) mogu imati veliki utjecaj na fotokatalitičku aktivnost i svojstva sintetiziranih materijala. Kompozit s masenim udjelom RGO-a od 0,05 % postigao je najveću stopu proizvodnje vodika u iznosu od 139 μmol/h/g te zadržao visoku fotostabilnost tijekom uzastopnih ispitivanja. Ugradnja RGO-a u matricu TiO2 utjecala je na poboljšanje učinkovitosti razdvajanja naboja, smanjenje energije zabranjene zone (Eg) te povećanje odziva na zračenje vidljivom svjetlošću, što je dovelo do učinkovitije proizvodnje vodika. Ispitivanja obje skupine materijala pokazala su da je tijekom solvotermalne sinteze pri uvjetima povišenog tlaka i temperature došlo do djelomične redukcije otopine GO u RGO. Nadalje, ovo istraživanje dokazalo je da vrlo niski maseni udjeli RGO-a mogu značajno poboljšati fotokatalitičku aktivnost i svojstva materijala. Suprotno tome, viši sadržaji RGO-a, u oba su slučaja negativno utjecala na proizvodnju vodika. Vjerojatni razlog tome je što veći sadržaj RGO-a u kompozitu utječe na blokiranje fotokatalitičke aktivne specifične površine, čime se sprječava prodor Sunčeva zračenja nužno potrebnog za aktivaciju materijala. Posljedica toga je niža fotokatalitička aktivnost ispitivanog materijala
Matrice za dostavu antibakterijskih nanočestica kod biomedicinskih implantata
No full textImplant-associated infections that develop after surgery, together with bacterial resistance to antibiotics, are the main obstacles to the successful use of different types of implants. To combat this, innovative antibacterial implant materials that can release antimicrobial agents locally and have a low potential for causing bacterial resistance are being sought. Among various antimicrobial agents, metal or metal oxide nanoparticles (e.g. AgNP, CuNP, CuONP, ZnONP) are attracting special attention as they offer diverse antibacterial mechanisms to mitigate bacterial resistance. The risk of cytotoxicity of NP can be reduced by immobilizing them in matrices. In this work, three matrices for the delivery of NP were investigated, namely polyelectrolyte multilayers (PEM), magnetron-sputtered ZnO thin films, and alginate hydrogels, some of which were mineralized with calcium phosphates (CaP) to enhance their biocompatibility. These matrices were chosen for their versatility, ease of preparation and the possibility to scale up the coating procedure. All matrices were extensively physico-chemically characterized and their biological properties were investigated to determine their potential for application. PEM were prepared on titanium surfaces using poly(amino acids), poly-L-lysine and poly-L-glutamic acid, with AgNP or CuONP incorporated as part of the multilayer. Compared to AgNP, CuONP was adsorbed in higher amount and formed aggregates on the surface, leading to increased roughness and hydrophilicity, as confirmed by energy dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometry, atomic force microscopy and water contact angle measurements. Biodegradable magnetron-sputtered ZnO thin films doped with Ag and Cu were prepared by co-deposition in a multi-source magnetron sputtering system, and their properties were compared. X-ray diffraction (XRD) of the prepared thin films revealed the formation of wurtzite structure in all cases. Opposing trends were observed for grain size and water contact angle with increasing Ag and Cu content. The biomimetic CaP deposition led to a partial surface coverage with an apatitic phase, improving surface hydrophilicity. Non-mineralized and mineralized alginate hydrogels with incorporated AgNP, CuONP and ZnONP were prepared at different pH values (7.4 and 9.0). Mineralization was performed in situ using a CaCl2 solution, which initiated both gelation and CaP mineralization in the hydrogels containing Na2HPO4. The influence of pH on mineralization was investigated with XRD and Fourier-transform infrared spectroscopy. It was revealed that the hydrogels prepared at pH 7.4 contained calcium-deficient hydroxyapatite (CaDHA), while amorphous calcium phosphate formed in the hydrogels prepared at pH 9.0 and remained stable over time. The presence of NP influenced mineralization, with larger CaDHA crystals forming in CuONP-containing hydrogels. NP incorporation had negligible effect on the rheological properties of the hydrogels, but mineralization notably influenced the critical strain values, leading to earlier network breakdown in mineralized samples. Ion release patterns were dependent on the type of matrices. The incorporation of NP in PEM prevented ion burst release. Magnetron-sputtered thin films followed a similar trend, with an initial rapid release followed by a slower, sustained release. CaP deposition slightly reduced Cu release and increased Ag release, Zn release remained unaffected. Alginate hydrogels showed the slowest initial release, which increased gradually over time, with variations depending on the type of NP and the pH conditions. Cu release from mineralized hydrogels at pH 7.4 and 9.0 and Zn release from mineralized hydrogels at pH 9.0 was reduced compared to the non-mineralized counterparts. The antibacterial effects of NP varied depending on the matrices in which they were incorporated. Among the NP investigated, CuONP exhibited substantial antibacterial performance in PEM and magnetron-sputtered Cu-doped ZnO, while AgNP were more effective in alginate hydrogels, particularly in those prepared at pH 7.4, where they inhibited Staphylococcus aureus growth by approximately 50 %. Interestingly, despite copper’s enhanced antibacterial activity in the other two matrices, CuONP-incorporated alginate hydrogels unexpectedly promoted the growth of S. aureus. NP-containing hydrogels exhibited lower antibacterial effect for Pseudomonas aeruginosa. Nevertheless, S. aureus was more difficult to inhibit than P. aeruginosa for other matrices. CaP mineralization improved the antibacterial properties of thin films, while its effect on NP-containing hydrogels was negligible. The only significant inhibition was observed for the mineralized CuONP-containing hydrogel prepared at pH 7.4 on P. aeruginosa. Regarding cytotoxicity, PEM matrices were biocompatible regardless of NP incorporation, with MG-63 cell viability exceeding 70 %. In contrast, magnetron-sputtered thin films were cytotoxic. However, this issue was proven to be possible to address with biomimetic CaP deposition. The results obtained confirmed high potential of PEM, magnetron-sputtered ZnO thin films and alginate hydrogels embedded with metal and metal oxide NP for biomedical antibacterial applications, providing a promising approach to developing biocompatible surfaces.Glavne prepreke uspješnoj primjeni različitih vrsta implantata su infekcije koje se javljaju nakon njihove ugradnje, a čije liječenje je dodatno otežano porastom bakterijske otpornosti na antibiotike. Inovativni materijali za implantate koji imaju lokalno antimikrobno djelovanje i malu vjerojatnost razvoja otpornosti bakterija smatraju se mogućim rješenjem tog problema. Pri tome kao antimikrobni materijali posebnu pažnju privlače nanočestice metala ili metalnih oksida (npr. AgNP-a, CuNP-a, CuONP-a i ZnONP-a) zbog višestrukih mehanizama antimikrobnog djelovanja, zbog čega je vjerojatnost razvoja bakterijske otpornosti mala. Potencijalna citotoksičnost NP-a može se smanjiti njihovom ugradnjom u odgovarajuće matrice. U ovom doktorskom radu istražene su tri matrice za ugradnju NP-a: polielektrolitni višeslojni filmovi (engl. polyelectrolyte multilayers, PEM), tanki filmovi ZnO naneseni magnetronskim rasprašenjem i alginatni hidrogelovi, od kojih su neki mineralizirani kalcijevim fosfatima (engl. calcium phosphates, CaP) kako bi se poboljšala njihova biokompatibilnost. Navedene matrice izabrane su zbog mogućnosti primjene na različitim površinama, jednostavnosti pripreme i mogućnosti skaliranja priprave. Sve matrice detaljno su fizikalno-kemijski okarakterizirane te su istražena njihova biološka svojstva kako bi se odredio njihov potencijal za primjenu. PEM-ovi su pripremljeni na titanijevim površinama upotrebom poliaminokiselina, poli-L-lizina i poli-L-glutaminske kiseline, u koje su AgNP-ovi ili CuONP-ovi ugrađeni kao dio višesloja. Rezultati energijski razlučujuće rendgenske spektroskopije, spektrometrije masa s induktivno spregnutom plazmom, mikroskopije atomskih sila i mjerenja kontaktnog kuta vode pokazali su da su se CuONP-ovi adsorbirali u većoj količini i agregirali na površini, što je dovelo do povećane hrapavosti i hidrofilnosti u usporedbi s AgNP-ovima. Magnetronski rasprašeni biorazgradivi tanki filmovi ZnO dopirani s Ag i Cu, pripremljeni su ko-depozicijom u sustavu s više izvora. Rendgenska difrakcija na polikristalnom uzorku (XRD) pokazala je nastajanje strukture vurcita u svim uzorcima. Uočeni su suprotni učinci povećanja udjela Ag i Cu na veličinu zrna i kontaktni kut s vodom. Biomimetska depozicija CaP-a rezultirala je djelomičnim prekrivanjem površina tankih filmova apatitnom fazom, čime je poboljšana hidrofilnost površine. Nemineralizirani i mineralizirani alginatni hidrogelovi s ugrađenim AgNP-ovima, CuONP-ovima i ZnONP-ovima pripremljeni su pri različitim pH vrijednostima (7,4 i 9,0). Mineralizacija se odvijala in situ uz upotrebu otopine CaCl2, koja je istovremeno služila za geliranje i mineralizaciju CaP kod hidrogelova koji su sadržavali Na2HPO4. Utjecaj pH na mineralizaciju istražen je XRD-om i infracrvenom spektroskopijom s Fourierovom transformacijom, pri čemu je utvrđeno nastajanje kalcij-deficijentnog hidroksiapatita (CaDHA) u hidrogelovima pripremljenim pri pH 7,4, dok se u hidrogelovima pripremljenim pri pH 9,0 istaložio amorfni kalcijev fosfat koji je ostao stabilan tijekom duljeg vremena. Ugradnja NP-a utjecala je na mineralizaciju, što se očitovalo formiranjem većih kristala CaDHA u hidrogelovima s CuONP. Međutim, utjecaj na reološka svojstva hidrogelova bio je zanemariv. S druge strane, mineralizacija je značajno utjecala na kritične vrijednosti deformacije hidrogelova, što je dovelo do ranijeg prekida mrežne strukture mineraliziranih uzoraka. Brzine otpuštanja iona razlikovale su se ovisno o vrsti matrice. Ugradnjom NP-a u PEM učinkovito se spriječilo naglo otpuštanje iona, a sličan trend pokazao se i kod tankih filmova nanesenih magnetronskim rasprašenjem. Naime, nakon inicijalno bržeg otpuštanja iona, uslijedilo je postupno otpuštanje. Mineralizacijom tankih filmova s CaP usporilo se otpuštanje Cu, dok se otpuštanje Ag povećalo, a otpuštanje Zn nije se značajno promijenilo. Kod alginatnih hidrogelova početno otpuštanje bilo je najsporije, a tijekom vremena postupno se povećavalo. Zamijećene su razlike u otpuštanju ovisno o vrsti ugrađenih NP i pH vrijednosti pripremljenih hidrogelova. Za razliku od odgovarajućih nemineraliziranih hidrogelova, otpuštanje Cu iz mineraliziranih hidrogelova pripremljenih pri pH 7,4 i 9,0 i otpuštanje Zn iz mineraliziranih hidrogelova pripremljenih pri pH 9,0, bilo je smanjeno. Antibakterijski učinci NP razlikovali su se ovisno o matricama u koje su bili ugrađeni. Među ispitanim NP-ima, CuONP-ovi pokazali su bolju antibakterijsku učinkovitost u PEM-u i Cu-dopiranim tankim filmovima ZnO nanesenim magnetronskim rasprašenjem, dok su AgNP-ovi bili učinkovitiji u alginatnim hidrogelovima, a posebno kod hidrogelova pripremljenih pri pH 7,4, kod kojih je došlo do inhibicije rasta Staphylococcus aureusa za približno 50 %. Iako je bakar pokazao bolju antibakterijsku aktivnost kod druge dvije matrice, kod alginatnih hidrogelova s ugrađenim CuONP-ovima došlo je do neočekivano induciranog rasta S. aureusa. Hidrogelovi s ugrađenim NP-ima pokazali su slabiji antibakterijski učinak za Pseudomonas aeruginosa. No, za druge matrice pokazalo se da je S. aureus bilo teže inhibirati nego P. aeruginosa. CaP-mineralizacija poboljšala je antibakterijska svojstva tankih filmova, a kod hidrogelova je njezin učinak bio zanemariv. Značajna inhibicija P. aeruginosa primijećena je jedino za mineralizirani hidrogel s ugrađenim CuONP-ovima pripremljen pri pH 7,4. Ispitivanjem citotoksičnosti utvrdilo se kako su PEM matrice biokompatibilne bez obzira na ugradnju NP-a, pri čemu je vijabilnost stanica MG-63 bila veća od 70 %. S druge strane, tanki filmovi naneseni magnetronskim rasprašenjem pokazali su citotoksičnost. Međutim, biomimetska CaP depozicija pokazala se kao učinkovita strategija za smanjenje citotoksičnosti. Dobiveni rezultati potvrdili su veliki potencijal PEM-ova, tankih ZnO filmova nanesenih magnetronskim rasprašenjem i alginatnih hidrogelova s ugrađenim NP-ima metala i metalnih oksida za primjene u biomedicini kao antibakterijski materijali. Te matrice stoga imaju značajan potencijal u razvoju biokompatibilnih površina
Aminonaphthalene and aminobiphenyl photoremovable protecting groups
No full textU okviru ovog doktorskog rada razvijene su nove fotokemijski uklonjive zaštitne skupine (PPG) s potencijalnom primjenom u organskoj sintezi i biologiji koje se temelje na različito supstituiranom aminonaftalenskom i aminobifenilnom kromoforu. Modelni spojevi aminonaftalena i aminobifenila pripravljeni su u obliku metilnih etera i acetilnih estera (fotokavezi) za izučavanje eliminacije alkohola, odnosno karboksilnih kiselina. Njihova priprava provedena je standardnim metodama sintetske organske kemije, pri čemu je strategija njihove sinteze temeljena na dobivanju različito supstituiranih alkohola aminonaftalena i aminobifenila koji su korišteni kao njihovi međuprodukti. Aminonaftalenski kromofori pokazuju maksimume u apsorpcijskom spektru pri 325 – 360 nm, dok aminobifenilni pri 280 – 315 nm te ih je moguće pobuđivati primjenom UV-A ili bliskog vidljivog zračenja u području valnih duljina 350 – 400 nm. Fotofizička svojstva fotokaveza određena su stacionarnom i vremenski razlučenom fluorescencijom te su korelirana s fotokemijskom reaktivnošću. Fotokemijska reaktivnost fotokaveza studirana je provedbom preparativnih osvjetljavanja u MeCN i MeCN-H2O (1:1) te izolacijom fotoprodukata. Utvrđeno je da su gotovo svi fotokavezi fotokemijski reaktivni u vodenom mediju, pri čemu su reakcije acetilnih estera učinkovitije u odnosu na metilne etere. Izolacijom fotoprodukata ustanovljeno je da većina aminonaftalenskih i aminobifenilnih fotokaveza podliježe reakciji fotohidrolize, osim u slučaju etera 8, 14 i 33, kod kojih je primijećeno da dolazi do fotokemijske reakcije N-demetiliranja. Na temelju kvantnih prinosa reakcije eliminacije acetata, uočeno je da aminobifenilni fotokavezi učinkovitije podliježu eliminaciji acetata (Φr = 0,04 – 0,32) u odnosu na aminonaftalenske fotokaveze (Φr = 0,01 – 0,22). Nadalje, studiranjem mehanizma fotokemijske reakcije cijepanja ustanovljeno je da aminonaftalenski i aminobifenilni esteri podliježu homolitičkoj reakciji cijepanja u singletnom pobuđenom stanju, dajući radikalske parove, koji naknadnim procesom prijenosa elektrona daju karbokatione i supstrate u obliku karboksilata. Slobodni radikali detektirani su laserskom pulsnom fotolizom i u vodenim otopinama pokazuju maksimume apsorpcije pri 340, 450 i 500 nm te vremena života od 10 – 100 µs. Potencijalna primjenjivost aminonaftalenskih i aminobifenilnih PPG u organskoj sintezi i biologiji prikazana je na nekoliko primjera eliminacije karboksilnih kiselina, uključujući biološki aktivne molekule (nesteroidni protuupalni lijekovi, neurotransmiter GABA i aminokiselina) i alkohole, uključujući ugljikohidrate. Dodatno, uspješno je provedena selektivna eliminacija aminonaftalenskog PPG u prisutnosti hidroksianilinskog PPG što ukazuje na kromo-ortogonalnu reakciju eliminacije.The PhD thesis features new photoremovable protective groups (PPGs) based on differently substituted aminonaphthalene and aminobiphenyl chromophores, with potential application in organic synthesis and biology. Model compounds of aminonaphthalenes and aminobiphenyls were prepared in the form of methyl ethers and acetyl esters (photocages) for the decaging study of alcohols and carboxylic acids, respectively. Their synthesis followed conventional methods in synthetic organic chemistry, whereby synthetic strategy was based on the preparation of differently substituted aminonaphthalene and aminobiphenyl alcohols, which were used as intermediates. Aminonaphthalene chromophores exhibit absorption maxima at 325 – 360 nm, while aminobiphenyl chromophores at 280 – 315 nm, and can be excited by UV-A or near-visible radiation in the 350 – 400 nm wavelength range. The photophysical properties of the photocages were investigated by steady-state and time-resolved fluorescence spectroscopy and were correlated with their photochemical reactivity. The photochemical reactivity of photocages was studied by preparative irradiations in MeCN and MeCN-H2O (1:1) and isolation of the photoproducts. The results showed that nearly all photocages are photochemically reactive in aqueous medium, with acetyl esters showing greater efficiency than methyl ethers. Analysis of the isolated photoproducts revealed that most of the aminonaphthalene and aminobiphenyl photocages underwent photohydrolyses, except for ethers 8, 14, and 33, which underwent photochemical N-demethylation reaction. Based on the quantum yields for the acetate elimination, the aminobiphenyl photocages react more efficiently (Φr = 0.04 – 0.32) than aminonaphthalene photocages (Φr = 0.01 – 0.22). Furthermore, mechanistic studies of the photoreactions revealed that aminonaphthalene and aminobiphenyl esters undergo homolytic cleavage on the single excited state surface, leading to the formation of radical pairs, which is followed by electron transfer giving the carbocations and substrates in the form of carboxylates. Free radicals were detected by laser flash photolysis, exhibiting absorption maxima at 340, 450, and 500 nm in aqueous solutions, with lifetimes ranging from 10 – 100 μs. The potential applicability of aminonaphthalene and aminobiphenyl PPGs in organic synthesis and biology was demonstrated through several examples of the photo-release of carboxylic acids, including biologically active molecules (nonsteroidal anti-inflammatory drugs, the neurotransmitter GABA, and amino acids), and alcohols, including carbohydrates. Furthermore, the selective removal of aminonaphthalene PPG in the presence of hydroxyaniline PPG was demonstrated, indicating their chromo-orthogonal elimination
Late antique community on the border of Pannonia and Noricum on the example of pottery finds from Lobor
No full textU doktorskom radu primarno je analizirano kasnoantičko keramičko posuđe s položaja Majka Božja Gorska i Pavlova pećina u Loboru. Ono je identificirano, klasificirano, katalogizirano i interpretirano u kontekstu njegovog nalaza unutar kasnoantičkog visinskog naselja i u svezi s njim. Osim kasnoantičkog, zabilježena je i manja količina ulomaka antičkog keramičkog posuđa koja dokazuje da taj položaj nije bio posve napušten ni tijekom razdoblja od 1. do 3. st. Unatoč tome, mnogo veća količina kasnoantičkog keramičkog posuđa od 3. do 6. st. potvrđuje da se revitalizacija kasnolatenske gradine, odnosno osnutak kasnoantičkog visinskog naselja u Loboru treba datirati nakon sredine 3. st. Najkasniji identificirani primjerci kasnoantičkog keramičkog posuđa mogu se datirati u prvu polovicu 6. st., a nisu pronađene posude koje bi se mogle sa sigurnošću datirati nakon toga vremena, unatoč tome što analize C14 pokazuju da je visinsko naselje spaljeno oko 580. god. Najveća količina ulomaka kasnoantičkog keramičkog posuđa može se datirati u 4. i prvu polovicu 5. st. Zabilježene su skupine uvoznog mediteranskog, regionalnog i lokalno proizvedenog keramičkog posuđa, a prema sadašnjem stanju istraživanja, nisu zabilježene skupine za koje bi se moglo sa sigurnošću tvrditi da su neromanskog podrijetla. Kasnoantičkom finom keramičkom posuđu pripisano je glazirano keramičko posuđe, posuđe s prevlakom, s uglačanim ukrasom i redukcijski i oksidacijski pečeno posuđe, a grubom sitnozrnato i krupnozrnato posuđe. Tipološko-kronološkom i kvantitativnom analizom ukupnog spektra kasnoantičkog keramičkog posuđa, kao i pojedinih skupina, daje se interpretacija prostornog uređenja visinskog naselja u Loboru, ali i dijela svakodnevnog života kasnoantičkog stanovništva noričko-panonskog graničnog područja, kojemu je pripadao loborski prostor, koji se odnosi na proizvodnju, distribuciju, korištenje i odbacivanje keramičkog posuđa.The lack of a large amount of pottery sherds dating from the 1st to the middle of the 3rd century at the site of Our Lady of the Mountain indicates that the population did not live there permanently during that period. After the establishment of peace and the organization of the Roman administrative authority, the population no longer needed to live on the hilltop and moved to the valley where a settlement with a necropolis was organized. It is not possible to give a precise answer to the question about the function of the hilltop site after the population moved to the valley. The first possibility is that part of the population still remained on the hilltop and lived there in a small, rural settlement of wooden houses, of which almost nothing has been preserved, except perhaps a few post holes that were not destroyed by medieval and modern graves. If, however, the population of the hilltop had completely abandoned their residence there, the possibility of retaining a cult place there remains. There is no evidence that the Late La Tène or perhaps Early Roman building beside the Early Christian complex was used for housing, as no significant amount of pottery was found there. More specifically, regarding the Romanization period, no large amount of pottery was found that could confirm that the hilltop was used as a settlement. Nevertheless, the pottery that has been found and can be dated to that period belongs to fine pots that may not be the pinnacle of Roman pottery, but for a settlement geographically isolated and therefore less connected to the rest of the Romanized part of the Noric-Pannonian border area, those finds are quite significant, even in the fragmented state in which they are. Fragments of thin-walled pottery, slipware, so-called eggshell ware and face pots belong to this period. The complete absence of fragments of coarse pots of the Late La Tène period tradition with a surface combed with vertical, slanted or irregular strokes is also significant, and this situation may indicate that the hillfort was really only a cult area where offerings to pagan deities were brought in fine tableware. This could be confirmed by the face pot fragment that are sometimes associated with pre-Roman beliefs, as well as the positions where earlier Roman pottery was found. All fragments of thin-walled pottery, slipware, face pots, etc. were found in trenches around the present-day church and early Christian church complex, i.e. around a potential earlier pagan sanctuary. Of the coarser pots that can be attributed to the 1st and 2nd century, only very small fragments of a relatively fine fabric can be singled out with certainty, decorated with short strokes with a small comb that sometimes overlap. For the earlier Roman period in Lobor, the find of Trajan's sestertius is also significant, which, together with a bowl of thin-walled pottery of probably Siscian production, is one of the earliest finds at the site of Our Lady of the Mountain, although there is a possibility that it was in later use. If Trajan's coin from Lobor is indeed of a later date, the thin-walled pottery bowl is the earliest confirmed find of Roman pottery in Lobor. Although it is attributed to Siscian production, based on the discovery of one bowl, it cannot be claimed that the process of Romanization arrived from the south, especially since the Lobor area has been connected with the area northwest of it since at least the Late Bronze Age, if not earlier. As it seems according to the current state of research and the analysis of pottery, life returned to the hillfort to a greater extent in the second third or maybe even the second half of the 3rd century. It is possible that the return of the population to the hillfort did not take place during a shorter period, but the findings of pottery suggest that. The number of vessels that can be attributed to the time around the middle of the 3rd century is greater than the number of those dated to the 1st and 2nd century, and in addition, the distribution of fragments of this later ware is no longer concentrated around the present-day church, but extends to the northern plateau and the area along the northern rampart. There are several fragments of relief terrae sigillatae that can be attributed to the Rheinzabern workshops and dated to the second half of the 2nd or the first half of the 3rd century. The only fragment of a Faltenbecher type cup can be dated from the end of the 2nd to the third quarter of the 3rd century. In this later group of early Roman pottery, Pannonische Glanztonware fragments are the most numerous. Although the sherds were not found in a closed context, based on analogies they are dated from the first quarter of the 2nd to the end of the 3rd century. It is indicative that the group of tableware that is dated at the latest is also the most common of the earlier Roman pottery. The largest number of Roman coins found at the site of Our Lady of the Mountain in Lobor can be dated from the middle of the 3rd century onwards. Those include all Roman coins except for the aforementioned Trajan's sestertius and the perforated sestertius of Maximinus I of Thrace, which was obviously in secondary use in a later period. Taking into account the dating of the coins and the group of pottery that appeared in the middle or second half of the 3rd century and whose quantity also increased significantly after that period, primarily glazed pottery, it can be determined with considerable certainty that life returned to the late La Tène hillfort immediately after the middle of the 3rd century and that the Late Antique hilltop settlement in Lobor was established. It is not excluded that the refugial character of the position of the Lobor hillfort was used earlier, perhaps during the Marcomannic Wars, but there is no evidence for this so far. A large amount of tableware cannot be attributed to that time, and certain types, such as unglazed mortars, are completely missing. In addition, there are no finds of Roman coins or other objects that can certainly be attributed to that time and interpreted in favor of a shorter settlement during the uncertain times of the second half of the 2nd century. The significant increase in the amount of pottery and the presence of almost all groups of pottery from the middle of the 3rd century, which are facts that indicate the permanent character of the hilltop settlement in Late Antiquity, could be connected with the turbulent times of the so-called crisis of the 3rd century. The beginning of that crisis period can be connected to the latest dated fragments of tombstones found as spolia at the site of Our Lady of the Mountain, as well as the stelae of Marcus Cocceius Superianus and Valerius Lucilianus found in the center of today's Lobor. It seems that since that time, the deceased are no longer buried in the necropolis of the lower settlement in Lobor, but in a so far unknown location, probably closer to the hilltop settlement, and later next to the early Christian complex in the center of the hilltop settlement. The discovery of graves on the artificially formed elevation north of the shrine of Our Lady of the Mountain did not result in a sufficient amount of pottery fragments that could confirm the position as a Late Antique cemetery, despite the discovery of one bone comb and the foot of a glass cup. The number of pottery fragments is negligible and there are no diagnostic sherds. As it seems so far, the abandonment of the permanent settlement in the valley along the Rieka stream and the establishment of the hilltop settlement was probably not only connected with the threats to the Roman population from the barbarian groups from the other side of the Danube, but also with the general state of insecurity during a greater part of the 3rd century. Late Antique glazed pottery marks the period from the second half of the 3rd to the middle or second half of the 5th century. Although it represents only 2.57% of the Late Antique pottery sherds, which is not an unusual number for sites far from the major workshop centers on the Danube or in northern Italy, glazed pottery represents a group in which almost all basic types and methods of decoration are represented. The bowls, plates, cups, bowls with handles and jugs belong mostly to tableware and mortars to kitchenware. Decorative motifs include grooved single and combed horizontal lines, single and combed undulations, small triangular, rectangular and irregular motifs made by rouletting, notches and oval motifs made with a sharp or rounded object on the rim, notches made using the chattering technique, stamped concentric circles, modeled wavy rim, and sometimes there are combinations of two decorative motifs. The decoration was sometimes carried out by painting with a red slip in the form of flames and flower petals, and the exteriors of several glazed bowls were decorated with burnished horizontal lines. Mortars decorated with slip painting and bowls with burnished horizontal lines, as well as related examples of glazed pottery with an intense olive green or yellow green glaze combined with red slip without a pattern should probably be dated earlier, to the second half of the 3rd and the first half of the 4th century, and glazed pottery of simpler forms, duller glaze and slip color if it was applied, and generally glazed pottery of poor glaze quality could be dated to the later period of the second half of the 4th and the first half of the 5th century. No examples of glazed pottery have been identified that could be could be dated only to the second half of the 5 th or even the 6th century, which is also a problem with other groups of Late Antique pottery from Lobor. Considering the theory about local workshops of glazed pottery, which has not yet been confirmed by field research, it was not possible to determine the workshop origin of the glazed pottery from Lobor, but based on the variety of fabrics, firing techniques, glaze and slip colors and methods of decoration, it is very likely that this glazed pottery originates from several workshops that were probably not located in the immediate vicinity of the hilltop settlement in Lobor. If such a workshop had existed nearby, the glazed pottery from Lobor would have been much more uniform, and there would have probably been fragments of tableware sets that have not been recorded so far. According to that and on the basis of analogies from the NoricPannonian border area, the origin of the glazed pottery from Lobor should be sought at the regional level in several workshop centers or smaller workshops. Unlike glazed pottery, slipware cannot be associated only with Late Antiquity, as is evident from the finds of thin-walled pottery, and rare examples remain almost until the end of late antique hilltop settlement and represent some of the latest late antique objects found in Lobor. In addition to thin-walled pottery, this group of pottery also includes terra sigillata, Pannonische Glanztonware, but also vessels of late antique forms with slip in shades of red and gray, which for the most part correspond to the forms of late antique glazed pottery. Simple oil lamps with a handle also appear in this group. Some of the reduction-fired jugs with a dark gray slip are similar in forms to jugs with burnished decoration and simple reduction-fired jugs without slip or processed surface. Considering the correlation of this group, most of the slipware, apart from the earlier groups of the 2nd and 3rd century, should be dated from the second half of the 3rd to the middle or second half of the 5th century. Here, the group of shallow bowls or deep plates that imitate North African red slipped pottery, specifically the form Hayes 61a and its variant Hayes 61a trans. Although the fabric, firing technique and slip quality are completely different, the orm of some examples is completely identical to North African examples and should be dated from the middle of the 4th to the middle of the 5th century. Although they do not represent original North African products, they appeared in the Noric-Pannonian at the height of North African import to the area in the 4th and 5th century and certainly belong to regional production, probably from the northern Italy that had the most contact with overseas areas such as North Africa and the Eastern Mediterranean. Original North African and Eastern Mediterranean ware was recorded only around the end of the 5th century. An undecorated fragment of an ARSW conical bowl of the Hayes 87 or 88 form and a fragment of a North African oil lamp of the Hayes II/Atlante X form decorated with triangle and palmette motifs, as well as an undecorated fragment of an Eastern Mediterranean LRC form Hayes 3E bowl were found in Lobor. The North African sherds can be dated to the end of the 5th or the beginning of the 6th century, and the Eastern Mediterranean to the last quarter of the 5th and the first quarter of the 6th century. Given the small number of fragments of Mediterranean pottery and the fact that earlier forms, which would belong to the period of more intensive import to the Noric-Pannonian area, were not found, so far it should be assumed that they were personal property that was probably brought to Lobor at the beginning of the 6 th century, and not objects of trade between the Mediterranean and the Lobor area. Perhaps their find in Lobor was connected to the relocation of part of the population from the territory of Poetovio, or it was even connected with the withdrawal of part of the population from Noricum Ripense. If this was indeed the case, it would confirm the gathering and refugial role of the fortified hilltop settlement in Lobor, which at the beginning of the 6th century was obviously an important church center where the early Christian complex with a church and a baptistery and possibly other churches was expanded and renovated. The assumption was that the hilltop settlement in Lobor certainly gathered the population of today’s Zlatar valley in unsafe periods, the population which usually lived on farms and settlements similar to the villa in Gornja Batina. The finds of imported Mediterranean tableware confirm that the settlement in Lobor also received residents of probably higher ranks from the threatened settlements of Noric-Pannonian border area. Although early Christian motifs, which are otherwise common, were not preserved on the mentioned imported pottery due to the high degree of fragmentation, it cannot be ruled out that the pottery was brought as part of the household of the Bishop of Poetovio, who is sometimes associated with the construction of the early Christian complex in Lobor, and perhaps with his stay in to an unexplored building on the south side of the site of Our Lady of the Mountain. As for the later forms of imported Mediterranean pottery, they have not been found in Lobor so far, so the question about the end of life in the hilltop settlement cannot be answered solely on the basis of pottery finds. Burnished pottery and pottery with burnished decoration from Lobor belong to the 4th and 5th centuries. A smaller part of that group of pottery belongs to open-shaped vessels, mostly bowls, decorated exclusively with polished horizontal lines, often on both sides of the vessel, for which the closest analogies were found in the Danube area of the eastern Noricum Ripense. Based on these analogies, the dating of the Lobor specimens of this group is placed from the middle of the 4th to the middle of the 5th century. Another group of the pottery with burnished decoration can be connected with the Pannonian part of the Danube limes, where three groups appear based on technological, typological and decorative characteristics. By analyzing these characteristics, the examples from Lobor were placed in the first two groups and dated from the middle to the end of the 4th century in the case of the first group and to the last quarter of the 4th and the beginning of the 5th century in the case of the second group. No fragments were found that could be attributed to the third group. It is possible that, due to the distance from the Danube, the immediate danger and the influence of barbarian groups, with the presence of which the appearance and popularity of this group of pottery is at least partially connected, the dating of the pottery with burnished decoration from Lobor should be extended and that at least until the end of the 5th in the workshops from which this pottery was procured for the hilltop settlement in Lobor, the proven production technology known from older potters was used. It is certain that one cannot expect exactly the same fabrics as in the workshops on the Danube or other larger production centers in Pannonia, and the situation is similar as with glazed pottery and slipware. The variety of fabrics and firing techniques points to several workshops from which the population of Lobor procured pottery of this group. What is perhaps surprising about this group, which is linked to the influence of barbarian groups, is that in Lobor it was not found in combination with stamped pottery. Not a single fragment with stamped decoration typical for the 6th century has been found so far. According to the current state of research, this should mean that the Lobor area was not under the direct influence of the Lombards, although it is sometimes placed on the eastern edge of the so-called Pólis Norikón. Based on the absence of stamped pottery, it is not possible to determine whether this means that in the middle of the 6th century the hilltop settlement in Lobor was already abandoned or at least that the number of inhabitants was significantly reduced, or whether this only happened in the last quarter of the 6 th century, to which the burned layers in the baptistery and on the late antique rampart were dated. There are only a few items from Lobor that can be dated to the period between the latest dated form of pottery and the date of the burned layer. These are objects from grave 50 and a buckle part from a destroyed grave that can be dated to the first half of the 6th century and an S-fibula of the Várpalota-Vinkovci type dated to the second third of the 6th century. They may also be joined by fragments of imported Mediterranean vessels if they were really transferred from another settlement and remained in use for a longer time. The least amount of information about the late antique community in Lobor was provided by reduction- and oxidation-fired fine pottery. The types are related to those of the groups of glazed pottery, slipware and pottery with burnished decoration. Reduction-fired fine pottery is typologically more closely related to the pottery with burnished decoration, and oxidation-fired fine pottery to glazed pottery and slipware. This group includes interesting and rare examples of stamped pottery, which differ from the 6th century stamped pottery according to their fabrics and decorative motifs and clearly belong to an earlier time. There are two fragments of oxidation-fired jugs or pots with stamped concentric circles, which are a typical late antique motif, while another example is decorated in a more complicated way. It is a fragment of an oxidation-reduction fired vessel of large dimensions, which was decorated on the outside with a combination of a stamped rosette, arc motifs made by double rouletting and an applied twisted band. An analogy for this last example should probably be sought in the area of western Noricum Mediterraneum, but in the group of coarse pottery, which in that area is generally more elaborately decorated. Although one of the assumptions was that the final phase of life in the hilltop settlement in Lobor could be explained using the results of the analysis of coarse pottery, it shows that simple, long-lasting forms of pots, jugs, bowls and