Croatian Digital Dissertations Repository
Not a member yet
10487 research outputs found
Sort by
Self-determination and social inclusion as indicators of transition to adulthood in people with intellectual disabilities
No full textTranzicija osoba s intelektualnim teškoćama (IT) u odraslu dob životno je razdoblje koje bi ih, uz formalnu i neformalnu podršku, trebalo pripremati za postizanje razvojnih zadataka i vrednovanih uloga odrasle dobi. Taj proces obilježen je izazovima vezanim uz ostvarivanje njihova samoodređenja i društvenog uključivanja, kao ključnih pretpostavki uspješnosti tranzicije i neovisnog življenja, a istraživanja o tome u Hrvatskoj su nedostatna. Stoga je glavni cilj ove doktorske disertacije bio mješovitim pristupom ispitati razinu samoodređenja i stupanj socijalne uključenosti osoba s IT iz njihove osobne perspektive te prema usporednoj procjeni njihovih roditelja/skrbnika (N=104) i stručnjaka/osoblja za podršku (N=31). Kvantitativni podaci prikupljeni su pomoću Općeg upitnika, te dvije inozemne, našim uvjetima prilagođene i dorađene skale procjene samoodređenja (Self-Determination Assessment - SDA, Hoffmann i sur. 2004) i socijalne uključenosti osoba s IT (Social inclusion scale - SIS, Secker i sur., 2007). U obradi podataka primijenjena je deskriptivna statistika, inferencijalne i multivarijatne metode. Analizirane su razlike u procjeni razine samoodređenja osoba s IT između obje skupine ispitanika, posebno uzevši u obzir stupanj IT i obrazovanje roditelja. Također su analizirane opće razlike u procjeni stupnja socijalne uključenosti posebno s obzirom na stupanj IT, rezidencijalni status i životni standard procjenjivanih osoba. Ispitana je i povezanost između rezultata na mjerama skala samoodređenja i socijalne uključenosti. Potvrđene su hipoteze o značajnim razlikama u procjeni socijalne uključenosti između roditelja i stručnjaka, pri čemu stručnjaci procjenjuju višu razinu socijalne uključenosti u odnosu na roditelje (H2), o pozitivnoj povezanosti samoodređenja i socijalne uključenosti (H3) te o razlikama u razinama samoodređenja s obzirom na stupanj IT, pri čemu osobe s lakšim stupnjem IT pokazuju višu razinu samoodređenja (H4). Djelomično je potvrđena hipoteza o razlikama u socijalnoj uključenosti s obzirom na stupanj IT (H5), iz perspektive stručnjaka viša je razina kod osoba s lakim stupnjem IT, dok iz perspektive roditelja nisu uočene značajne razlike. Nisu potvrđene hipoteze o značajnim razlikama u općoj procjeni samoodređenja između roditelja i stručnjaka (H1) kao ni prema stupnju obrazovanja njihovih roditelja (H6). Također, nisu utvrđene značajne razlike u procjeni socijalne uključenosti s obzirom na rezidencijalni status (H7) i životni standard (H8). Kvalitativnim pristupom, primjenom Vodiča za individualni polustrukturirani intervju, ispitana su subjektivna iskustva i doživljaji 21 osobe s lakim stupnjem IT, u dobi od 22 do 39 godina o mogućnostima samoodređenja i socijalne uključenosti u svakodnevnom životu. Tematskom analizom pokazalo se da osobe s IT imaju vrlo ograničene mogućnosti za ostvarivanje samoodređenja, osobito u pogledu mogućnosti stjecanja prihoda i raspolaganja financijskim sredstvima, osobnoj autonomiji, donošenju odluka, te ostvarivanju spolno-partnerskih uloga. Istaknule su se i njihove težnje za preuzimanjem uloga odrasle dobi. Ukazali su na ograničeno sudjelovanje u zajednici, digitalnu isključenost pa i socijalnu izolaciju što ne govori u prilog poželjne razine socijalne uključenosti. Sveobuhvatni rezultati istraživanja potvrđuju značajnu uzajamnu povezanost samoodređenja i socijalne uključenosti. No u cjelini, nezadovoljavajući su i nepovoljni za osobe s IT u pogledu doprinosa uspješnosti tranzicije u odraslu dob. Stoga su, temeljem izvornih nalaza ovoga rada i njihova povezivanja s drugim znanstveno-relevantnim spoznajama, kao i primjerima dobre inozemne prakse, zaključno definirane i smjernice za kreiranje ili unaprjeđenje tranzicijske podrške osobama s IT na mikro, mezo i makro razini potencijalnog djelovanja.The transition to adulthood of people with intellectual disabilities (ID) is a period of life that should prepare them, with formal and informal support, to achieve developmental tasks and valued roles of adulthood. This process is characterized by challenges related to the realization of their self-determination and social inclusion, which are key assumptions for the success of the transition and independent living, and research on this topic is insufficient in Croatia. Thus, the main goal of this doctoral dissertation was to examine the level of self-determination and the degree of social inclusion of people with ID from their personal perspective as well as the comparative assessment of their parents/guardians (N=104) and the professionals/support staff (N=31). Quantitative data were collected using the General Questionnaire and two foreign scales of self-determination assessment (Self-Determination Assessment - SDA, Hoffmann et al. 2004) and social inclusion of people with ID (Social inclusion scale - SIS, Secker et al., 2007), which were adapted and adjusted to our conditions. Descriptive, inferential statistics and multivariate methods were applied in data processing. Differences in the assessment of the level of self-determination of individuals with ID between both groups of respondents were analyzed, especially taking into consideration the level of ID and the academic level of their parents. General differences in the assessment of the level of social inclusion were also analyzed, especially regarding the level of ID, residential status and living standard of the assessed individuals. The correlation between the results on the measures of self-determination and social inclusion scales was also examined. The hypothesis of significant differences in the assessment of social inclusion between parents and professionals is confirmed, with professionals reporting a higher level of social inclusion compared to parents (H2). A positive correlation between self-determination and social inclusion was confirmed (H3). Also, the hypothesis of significant differences in the levels of self-determination regarding the degree of ID was confirmed. Individuals with a mild degree of ID have a tendency showing a higher level of self-determination (H4). The hypothesis of differences in social inclusion between levels of ID (H5) was partially confirmed; from the perspective of professionals, the level is higher in individuals with a mild level of ID, while from the perspective of parents, differences were not significant. The hypotheses of the significance of differences in the assessment of self-determination between parents and professionals (H1) and the level of education of the parents (H6) were both rejected as were the hypotheses of differences in social inclusion according to residential status (H7) and living standard (H8). Using a qualitative approach, applying the Guide for Individual Semi-Structured Interviews, the subjective experiences, and perceptions of 21 individuals with mild ID, aged 22 to 39, were examined regarding the possibilities of self-determination and social inclusion in everyday life. Thematic analysis showed that people with ID have very limited possibilities for achieving self-determination, especially in terms of the possibility of earning an income and managing financial resources, personal autonomy, decision-making, and achieving intimate and partner roles. Their aspirations to assume adult roles were also notable. They pointed to limited participation in the community, digital exclusion, and even social isolation, which does not speak in favor of the desired level of social inclusion. The comprehensive results of the research confirm the significant mutual connection between self-determination and social inclusion. However, overall, they are unsatisfactory and unfavorable for people with ID in terms of contributing to the success of the transition to adulthood. Therefore, based on the original findings of this research and its connection with other scientifically relevant findings, as well as examples of good international practice, guidelines for creating or improving transitional support for people with ID at the micro, meso and macro levels of potential action have been defined
Effects of levothyroxine therapy on markers of endothelial dysfunction in subclinical hypothyroidism
No full textSupklinička hipotireoza (SH) stanje je povišene koncentracije tireotropina (TSH) uz normalnu koncentraciju slobodnog tiroksina (FT4) i slobodnog trijodtironina (FT3) u serumu. Ovisno o vrijednosti povišenog TSH dijeli se na blaži oblik SH (TSH ≤ 10,0 mIU/L) i teži oblik SH (TSH > 10,0 mIU/L). Supklinička hipotireoza je najčešće asimptomatska bolest, no predstavlja neovisni čimbenik rizika za razvoj kardiovaskularnih bolesti zbog razvoja endotelne disfunkcije i ateroskleroze.
Cilj istraživanja bio je utvrditi učinak levotiroksina u bolesnika s blažim oblikom SH na koncentraciju biljega endotelne disfunkcije u krvi (endokan, asimetrični dimetilarginin (ADMA) i endotelin-1 (ET-1)) te drugih biokemijskih kardiovaskularnih čimbenika rizika (trigliceridi, ukupni kolesterol, LDL (lipoproteini niske gustoće) kolesterol i ne-HDL kolesterol (sve aterogene lipoproteinske čestice koje nisu lipoproteini visoke gustoće), visokoosjetljivi C-reaktivni protein (hs-CRP), broj leukocita, trombocita te srednji volumen trombocita (MPV)), budući da je liječenje ovih bolesnika individualno, a klinička važnost i korisnost liječenja jesu i dalje predmet čestih rasprava.
U ovoj prospektivnoj studiji ispitanici (18 - 75 godina, oba spola) su obrađivani putem sistematskih pregleda u Specijalnoj bolnici Agram i pri specijalističkom pregledu u Klinici za onkologiju i nuklearnu medicinu Kliničkog bolničkog centra Sestre milosrdnice. Studijom je obuhvaćeno 29 odraslih osoba s postavljenom dijagnozom blažeg oblika SH kojima je pri uključivanju u istraživanje propisana nadomjesna terapija levotiroksinom, 32 odrasle osobe s postavljenom dijagnozom blažeg oblika SH kojima terapija nije propisana i 30 zdravih ispitanika s urednom funkcijom štitnjače koji su prema spolu i dobi odgovarali bolesnicima s SH. Biljezi endotelne disfunkcije i odabrani biokemijski biljezi određeni su kod svih ispitanika na početku istraživanja te u bolesnika s propisanom terapijom levotiroksinom nakon šest mjeseci liječenja od uspostavljene eutireoze i u bolesnika kojima terapija nije propisana nakon šest mjeseci praćenja.
Bolesnici s blažim oblikom SH pokazali su značajno više serumske koncentracije ADMA, endokana, LDL kolesterola i ne-HDL kolesterola u usporedbi sa zdravim ispitanicima. U bolesnika sa SH nakon šest mjeseci liječenja levotiroksinom od uspostavljene eutireoze došlo je do značajnog smanjenja koncentracije endokana i ukupnog kolesterola. U skupini bolesnika sa SH bez terapije levotiroksinom nakon šest mjeseci praćenja značajno se povećala koncentracija ET-1, dok nije bilo promjena u koncentracijama ADMA i endokana.
Ovo istraživanje pokazalo je da bolesnici s blažim oblikom SH imaju povećanu koncentraciju biljega endotelne disfunkcije i dodatnih biokemijskih čimbenika rizika u krvi što bi moglo upućivati na povećani rizik za razvoj kardiovaskularnih bolesti. Temeljem praćenja odabranih parametara endotelnog statusa također je pokazano da je uvođenje supstitucijske terapije levotiroksinom kod ovih bolesnika dovelo do poboljšanja endotelnog statusa i potencijalno smanjenja rizika za razvoj kardiovaskularnih bolesti te dodatno usporavanje napredovanja hipotireoze u klinički manifestnu bolest.
Ključne riječi: supklinička hipotireoza, levotiroksin, asimetrični dimetilarginin, endotelin-1, endokanSubclinical hypothyroidism (SCH) is a condition characterized by elevated serum thyroid-stimulating hormone (TSH) concentrations with normal free thyroxine (FT4) and free triiodothyronine (FT3) concentrations. According to serum TSH concentrations, SCH can be classified into mild (TSH ≤ 10.0 mIU/L) and severe (TSH > 10.0 mIU/L) forms,. Although most patients with SCH are asymptomatic, the condition can negatively affect the cardiovascular system.
The aim of this study was to evaluate whether levothyroxine therapy affects serum concentrations of endothelial dysfunction markers (endocan, asymmetric dimethylarginine (ADMA) and endothelin-1 (ET-1)) as well as other biochemical cardiovascular risk markers, including triglycerides, total cholesterol, low-density lipoprotein (LDL) cholesterol, non-high-density lipoprotein (non-HDL) cholesterol, high sensitivity C-reactive protein (hs-CRP), leukocytes, platelets and mean platelet volume (MPV), in patients with mild SCH.
In this case-control prospective study, participants were recruited during routine health examinations conducted by hospital medical specialists. Patients with SCH were enrolled at the Department of Internal Medicine, Special Hospital Agram, and the Clinic of Oncology and Nuclear Medicine, Sestre milosrdnice University Hospital Centre. The study included 61 adult patients with a mild form of SCH (under 75 years) and 30 healthy controls matched to the patient group by sex and age. Written informed consent was obtained from all participants. Clinical decisions regarding levothyroxine substitution therapy were made by medical specialists based on individual examinations. Of the 61 patients with confirmed SCH, 29 were prescribed levothyroxine substitution therapy, and 32 were not. Baseline concentrations of endothelial dysfunction markers (endocan, ADMA, and ET-1), and other biochemical markers were measured in all participants. These measurements were repeated in 29 SCH patients after six months of levothyroxine treatment (following the achievement of euthyroidism) and in 32 SCH patients who did not receive levothyroxine therapy after six months of follow-up.
Our study demonstrated elevated concentrations of ADMA, endocan, LDL cholesterol and non-HDL cholesterol in patients with a mild SCH compared to healthy controls. In SCH patients treated with levothyroxine for six months after achieving euthyroidism, we observed a significant decrease in endocan concentrations and total cholesterol concentrations. In contrast, in the group of SCH patients who did not receive levothyroxine therapy a significant increase in ET-1 concentration was observed. However, no significant changes in ADMA or endocan concentrations were noted in this group.
Our study demonstrated that patients with mild SCH exhibited elevated concentrations of cardiovascular disease risk factors, including endocan, ADMA, LDL cholesterol, and non-HDL cholesterol. Early diagnosis and levothyroxine treatment of SCH could offer potential benefits; first, by reducing the risk of cardiovascular-related mortality through improved endothelial function, and second, by preventing the progression to clinically manifested hypothyroidism
Principles of underlying structural modelling of bibliographic data in Bosnian and Herzegovinian vakufnamas
No full textU Gazi Husrev-begovoj biblioteci u Sarajevu se čuva oko 1600 vakufnama (zakladnica, zavještajnica, zadužbinskih povelja) iz raznih dijelova Bosne i Hercegovine, koje se odnose na period od 16. do 18. vijeka, u kojima se bilježi porijeklo i namjena zadužbina, te koje stoga, predstavljaju primarni izvor za izučavanje povijesti nastanka pojedinih lokaliteta i velikog broja nepokretnih kulturnih dobara. Zbog heterogenosti praksi obrade građe u bibliotekama i srodnim zajednicama, kao i zbog specifičnosti obrade pojedinih vrsta građe, unatoč razvoju mnogobrojnih protokola za razmjenu podataka, evidentna je nedovoljna saradnja među zajednicama koje se bave organizacijom bibliografskih objekata zastupljenih bibliografskim zapisima. S ciljem iskorištavanja znanja sadržanog u vakufnamama i njihove promocije na globalnoj mreži, potrebno je modificirati reprezentaciju toga znanja u računalnom okruženju na semantički razumljiv način. U ovom doktorskom radu je istražena mogućnost uspostavljanja načela strukturnoga modeliranja bibliografskih podataka za bosanskohercegovačke vakufname radi poboljšanja organizacije i prikaza informacija o vakufnamama u bibliotečkim katalozima i bibliografskim informacijskim sistemima, unutar okvira za prezentaciju pametnih podataka, koji postaje paradigma budućeg načina oblikovanja Weba u semantički web. Stoga su vrednovane dvije različite metodologije konceptualizacije bibliografskog univerzuma za upravljanje informacijama o kulturnoj baštini - metodologija entiteta i veza (FRBR - LRM), kao i interpretacija modela iz FR-porodice primjenom objektno-orijentirane metodologije (FRBRoo). U tu svrhu je bilo potrebno utvrditi koja su svojstva vakufnama važna za bibliografsku organizaciju, iz aspekta primarnih korisnika ovih dokumenata, što je istraženo prikupljanjem i evaluacijom podataka, tehnikama anketnog upitnika, pojmovnog mapiranja i sortiranja kartica, koje su dopunjene polustrukturiranim intervjuima. Ovaj doktorski rad, doprinos je razvoju i implementaciji okvira za strukturno modeliranje bibliografskih podataka i njihovoj integraciji u semantički web, budući da sudjelovanje u semantičkom webu postaje dijelom odgovornosti za bibliotečke zajednice. Uspostavljanje odnosa između IFLA-inih konceptualnih modela i njihove implementacije, pridonijeti će prijeporima očuvanja i diseminacije informacija sadržanih u vakufnamama.The Gazi Husrev-beg Library in Sarajevo holds about 1600 vakufnamas (endowments, endowment charters) from various parts of Bosnia and Herzegovina, which date from 16th to 18th century, that are documents concerning the foundation and purpose of endowments, and which, therefore, represent primary sources for studying the history of the origin of individual localities and a large number of immovable cultural objects. As a result of heterogeneus collection management practices in libraries and other related communities, as well as due to the specifics of the processing of certain types of materials, insufficient cooperation between communities dealing with the organization of bibliographic objects represented by bibliographic records is evident. In order to exploit the knowledge contained in vakufnamas and promote them on the global network, it is necessary to modify the representation of that knowledge in a semantically understandable way. In this doctoral thesis, within the smart data presentation framework, which is becoming the paradigm of the future way of shaping the Web into the Semantic Web and with the aim to improve the organization and presentation of information on endowments in library catalogs and bibliographic information systems, the possibility of establishing underlying principles of structural modeling of bibliographic data for Bosnian and Herzegovinian vakufnamas was investigated. Accordingly, it is proposed to evaluate two different methodologies of conceptualisation of the bibliographic universe for cultural information management, entity-relationship methodologie (FRBR - LRM) and the interpretation of the FR family of models using object-oriented methodologie (FRBRoo). For this purpose, it was necessary to determine which properties of the endowments are important for the bibliographic organization, from the perspective of primary users of these documents, therefore different data collection tehniques were used - questionnaire, conceptual mapping and card sorting techniques, which were supplemented by semi-structured interviews. This doctoral thesis is a contribution to the development and implementation of a framework for structural modeling of bibliographic data and their integration into the Semantic Web, as participation in the Semantic Web becomes part of the responsibility for library communities. Establishing a relationship between IFLA's conceptual models and their implementation will contribute to the efforts of preservation and dissemination of information contained in endowments. The doctoral thesis on 217 numbered pages contains the text in 8 chapters, which are preceded by the Introduction. The chapters are titled as follows: Explanation, Research Methodology, Definition, Characteristics and Significance of Vakufnamas in Bosnia and Herzegovina, Organization of Bibliographic Information in the Semantic Web, Conceptual models of the Bibliographic Universe, Research on the Bibliographic Structure for Bosnian and Herzegovinian Vakufnamas, Structural Modeling of Bibliographic Data for Bosnian and Herzegovinian Vakufnamas and Concluding Considerations, followed by a list of literature, appendices, list of tables, list of pictures, biography and list of publicly published works of the author. The thesis contains 28 figures and 4 tables, as well as a list of cited literature. The Introduction summarizes the changes that the process of bibliographic organization of information goes through in the sense of a new conceptual view of the universe of recorded knowledge, alongside which the development of semantic web standards runs parallel, emphasizing the relevance of these standards for bibliographic data. In the first chapter entitled Explanation, a new conceptual view of the bibliographic universe presented in IFLA's FR - family of models is presented, after which the shortcomings of the traditional approach are pointed out, emphasizing the state of practice of manuscript materials. After that, the fundamental characteristics of endowments are presented, where the features that are interesting from the aspect of bibliographic organization are emphasized. The second chapter is titled Research Methodology and provides a description of the theoretical framework, goals and research questions, followed by a description of the plan, phases, methods, materials and subjects of the research. In addition to the above, the chapter provides an overview of earlier research. The third chapter, entitled Definition, Characteristics and Significance of Vakufnamas in Bosnia and Herzegovina, considers vakufnamas (endowment charters) from the aspect of social significance for Bosnia and Herzegovina, points to the current cataloging practice related to these archival documents kept in the Gazi Husrev-bey library in Sarajevo. After that, an overview of the practice of cataloging manuscript material in libraries is given, in a concise form, with a special emphasis on the problems of access to primary sources for research, including the ways of access to endowments. The fourth chapter, entitled Organization of Bibliographic Information in the Semantic Web, first states the characteristics of the semantic web and the differences in the infrastructure and approach to data analysis compared to the traditional web and relational databases, including the definition and properties of linked data. After that, the transition process of IFLA's standards into the environment of linked data is presented, where the position of ISBD and UNIMARC within the contemporary global bibliographic ecosystem is particularly indicated. The chapter then provides an overview of the new cataloging codes aligned with conceptual models and the characteristics of authority control within the new bibliographic environment. The fifth chapter is entitled Conceptual Models of the Bibliographic Universe and presents an overview of the evolution of the concept of universal bibliographic control until the publication of the consolidated and unified IFLA LRM model, within the framework of the existing metadata standards of the LAM community and their principles. In this chapter, an exhaustive presentation of the IFLA LRM model, as a model of entities and relations, is offered, where at the same time the specificities of the corpus of vakufnamas are indicated in the context of nonbibliographic data on endowment buildings. After that, the relationship between the IFLA LRM and the FRBRoo model is pointed out and an object-oriented version of the model from the FR-family is presented, which enables event-based data modeling and which is the result of a dialogue between the museum and library community, initiated by the interoperability of existing conceptual models. The sixth chapter is entitled Research on the Bibliographic Structure for Bosnian and Herzegovinian Vakufnamas and provides an overview of survey questionnaire techniques, conceptual mapping and card sorting, and complementary semi-structured interviews that were conducted for the purposes of data collection. The process of selecting participants and the way of conducting the research is presented in detail, along with a review of the literature related to the current research practices of the new conceptual framework. The question of organization of the phenomenon of vakufnamas as super-works is presented as a requirement for the organisation of vakufnamas written for endowment buildings. In the focus of the survey research and the card sorting task, the characteristics of user expectations regarding the bibliographic organization of these documents, and the specifics of the mental models, were considered for comparison with the entities and relationships declared in the IFLA LRM and FRBRoo models. The seventh chapter, entitled Structural Modeling of Bibliographic Data for Bosnian and Herzegovinian Vakufnamas, contains the results of the conducted research, the analysis of the data collected through the research, and a discussion of issues that have been identified as relevant in the context of the universe of interest, as a result of the literature review, preliminary discussions with the managers of the document collections and their users, and the conducted research. The question of the role of non-bibliographic data in the context of vakufnamas was primarily considered through survey research. Through conceptual mapping, it was established that the participants express a conceptualization of the bibliographic universe which, due to the certain level of abstraction it includes, corresponds to the multi-entity models. The research demonstrates how participants, for the purposes of expressing complex relations of derivation, within the multi-entity model they prefer, identify the characteristics of the relevant universe of discourse. Sorting the cards made it possible to compare the users' mental models with the conceptualization offered in the IFLA LRM. Furthermore, an account of how to model the historical context for the specific collection of sidjils of vakufnamas, that has been identified as significant for users, is presented, along with the issue of modeling manuscripts and works of art in the IFLA LRM model. In the part of the chapter related to the FRBRoo model, the modeling of vakufnamas as manuscripts is presented and the issue of modeling intellectual processes is discussed. In the context of endowments for building objects, the possibilities of the FRBRoo model for recording intellectual processes within the universe of endowments, in terms of performance and complex work, are pointed out. The final chapter, Concluding Considerations, summarizes the conclusions of each chapter with a discussion of key results. It is determined that the IFLA LRM and FRBRoo models represent a suitable framework for establishing the principles of structural modeling of bibliographic data for the selected corpus of vakufnama
Radical informel in Croatian art from 1956 to 1962
No full textRadikalni enformel jedna je od iznimno značajnih umjetničkih pojava u hrvatskoj umjetnosti kasnih pedesetih i ranih šezdesetih godina prošlog stoljeća. Uvođenjem novih materijala, postupaka i materičkih istraživanja, radikalni enformel predstavlja reakciju i kritiku „tradicionalne modernosti“, posebno figurativne i mimetičke umjetnosti. Ovaj rad propituje promjenu percepcije o samoj prirodi slike i forme kroz djela radikalnog enformela, kao i ulogu glavnih eksponenata u formiranju koncepta nepikturalne, nesemantičke i neprikazivačke tipologije enformelnog slikarstva unutar hrvatske povijesti umjetnosti. Osim pet glavnih predstavnika (Gattin, Feller, Jevšovar, Seder, Kristl), rad predstavlja i individualne poetike sedam umjetnika koji su u jednoj etapi svog stvaralaštva ostvarili djela materičkog enformela ili su se s nekoliko likovnih ostvarenja približili radikalnoj enformelnoj orijentaciji (Kulmer, Jelenić, Hruškovec, Horvat, Vaništa, Sablić i Missia) u razdoblju od 1956. do 1962. godine, kao i kasnije recidive i (dis)kontinuitete enformela kod pojedinih autora. Pored dosadašnjih teoretskih i kritičkih modela, uvažavajući dosadašnja saznanja, arhivske izvore, dokumentaciju i relevantnu literaturu, kao i kataloge izložbi koji su se dovodili u vezu s enformelom u Hrvatskoj, disertacija pruža i neka druga moguća tumačenja radikalnog enformela kroz koncepte entropije, besformnog, estetike ružnoga, odnosno brutalne estetike (deformacije, disfiguracije, ništavljenje značenja i oblika). Uz spomenuto, disertacija sagledava i propituje enformelno stvaralaštvo s drugih kritičkih pozicija kao što su rodne teorije te kroz društvenopolitičke kontekste prema kojima recepcija radikalnog tipa enformela nije imala značajniju institucionalnu podršku, niti su glavni predstavnici imali društveni i umjetnički status kao pojedini umjetnici pikturalne, umjerenije enformelne orijentacije. Poseban doprinos koji ovaj rad nastoji dati, očituje se u katalogizaciji obrađivanih djela te opsežnoj i cjelovitoj sintezi pojave radikalnog enformela u hrvatskoj umjetnosti. Analizom i komparacijom pojedinačnih djela glavnih eksponenata radikalnog enformela, ukazuje na sličnosti i razlike s djelima europskog i svjetskog enformela. Također, rad kontekstualizira radikalni enformel u hrvatskoj umjetnosti unutar onodobne jugoslavenske likovne scene i kao dio svjetskih enformelističkih tendencija.Radical Art Informel is one of the particularly important chapter in Croatian art of the late 1950s and early 1960s. By introducing new materials, artistic procedures, and materic experiments, radical Informalism epitomizes the critique of “traditional modernity”, especially that of figurative and mimetic art as well as a reaction to the advent of geometric abstraction. This thesis is concerned with the emergence, reception, interpretation, and definitions of radical Art Informel in the period from 1956 to 1962, as well as its influence on later art of the 1970s and 1980s. This work questions the shift in the perception of the very nature of painting and art through radical Informalist works, as well as of the main exponents’ role in the formation of the concept of the non-pictorial, non-semantic, and nonmimetic typology of Informalist painting within Croatian art history. A particular contribution which this dissertation aims to provide lies in the cataloging of previously-expounded-on artworks, their interpretation, as well as an extensive and exhaustive synthesis of the emergence of radical Art Informel in Croatian art based on previous theoretical, critical, and historic interpretations of this artistic phenomenon in Croatian art. By analyzing and comparing individual artworks of the protagonists of radical Informalism in Croatia, this work will identify their differences and similarities when compared to artworks of European and global Art Informel. In addition to this and alongside earlier theoretical and critical models which have been related to Art Informel in Croatia, this thesis provides some other possible interpretations of radical Informalism based on, for example, Rosalind Krauss and Yve-Alain Bois's concepts of entropy and the formless, the aesthetics of ugliness (Umberto Eco, Theodor Adorno, Karl Rosenkranz, Hal Foster, Jean Dubuffet, Georges Bataille), the notions of deformation and disfiguration or the ideas of Georges Mathieu on the negation of meaning and dissolution of shapes. Beside the aforementioned, this thesis regards and questions Informalist creation from other critical perspectives, such as that of gender theory. Apart from the oeuvres of the five protagonists (Ivo Gattin, Eugen Feller, Marijan Jevšovar, Đuro Seder, Vlado Kristl), this work also presents the individual poetics of seven artists who, in one phase of their artistic practice, created works of materic Informalism or approached radical Art Informel in several of their artworks (Božidar Jelenić, Tomislav Hruškovec, Ferdinand Kulmer, Miljenko Horvat, Josip Vaništa, Rudolf Sablić, and Frano Missia), all in the period from 1956 to 1962. Taking into consideration previous findings, archival resources, documentation and literature on the subject, as well as exhibition catalogs and some newer interpretations, this thesis also elucidates radical Art Informel through socio-political contexts according to which the reception of the radical type of Art Informel did not enjoy significant support from art institutions, nor did its main exponents have an equal social and art status as did individual artists of a pictorial, more moderate Informalist orientation. Furthermore, this work contextualizes radical Art Informel in Croatian art within the Yugoslav art scene of the time and as a component of global Informalist tendencies. It takes a critical stance towards the very thesis on radical Art Informel and questions the validity of its name and definition, providing additional interpretations and categorizations of Informalism within Croatian art history. The intention of this thesis is to contribute to the broader perception and understanding of the frameworks within which this artistic phenomenon appeared, as well as its unique positions and roles in the context of Yugoslav art, its disparities compared to other art centers of former Yugoslavia, and its similarities to some South European art centers. The intention is also to clarify the specific socio-political context and social status of these dissident artists within the framework of extrainstitutional support and opposition towards mainstream art movements. Subsequently, the work will provide morphological stylistic characteristics of the materic, or rather radical variant of Art Informel which is differentiated from works within the oeuvres of the artists that shall be covered here, compared to the more pictorial variant of Informalism. It will also compare these works with the works of Art Informel artists from Europe and around the globe. The term “Art Informel”, even in its formative years, implied a whole host of variations with differing characteristics and nominations. Shortly after they appeared in France, similar or equivalent phenomena started appearing in Germany, Spain, Italy, and other countries. One could have concluded that what was in question was a dominant art practice in post-war Europe. It therefore does not come as a surprise that this phenomenon appeared in Yugoslavia as well, which was a more liberal country in terms of its political convictions, and with more open borders compared to other European countries within the Socialist order. Up to this point, numerous critical texts and articles have been written on the topic of Art Informel, or more precisely that of the radical type of Informalism. It is also mentioned in the systematization of Croatian art of the 20th century, as well as within individual biographies of its most important proponents. However, within the literature to date, radical Informalism has yet to be the topic of a comprehensive monograph, though it presents an important segment of the national artistic patrimony and is of international import. Through a methodological approach, using various art-historical and hermeneutic methods, this thesis aims to question several hypotheses, the first of which being that radical Art Informel strives towards the negation of painting, or rather leans towards the concept of the anti-painting by making destructive and radical interventions in the material or matter, by researching and introducing new unconventional art materials, media, art processes, and pursuing the abolishment of the “beauty” of the painting. The second hypothesis would be that radical Informalist artworks possess fundamental stylistic, morphological, and discursive attributes of the non-semantic and antipictorial, which, on a formal level, are manifested in an abstract, mainly materic and monochrome painting style that, in some individual cases, transgresses the boundaries of the specificity of the medium, the two-dimensionality of the painting, and borders on sculpture (Gattin and Feller). The third hypothesis which shall be questioned is that radical Art Informel is predominantly present in the oeuvre of those artists who had not earned recognition on the art scene during the time of the appearance of Informalism, nor were they to be found within Masters’ Workshops. Rather, these were individual artists, members of groups such as Gorgona or artists close to this group, who took an antipainterly approach to art as well as a particular (outsider) existentialist outlook on life and artistic creation. The thesis is subdivided into several chapters. The first chapter provides insights into the various nominations (names), characteristics, and theoretical definitions of Art Informel, as well as its emergence in Europe and the world. Apart from France, Italy, Spain, and Germany, Art Informel and Expressionism appeared in Yugoslavia, as well as in individual Eastern European countries, and in the art of the United States, Canada, Japan, Argentina, and Brazil. As has already been touched upon, besides critical and theoretical models of interpreting Art Informel by Tapié, Mathieu, Argan, Dorfles, Crispolti, Barilli, Calvesi, and Eco, as well as interpretations of American action painting by Rosenberg and Greenberg, emphasis will be placed on the notion of the informe (that which has no form)—which Rosalind Krauss and YveAlain Bois adopted from George Bataille—and Rudolf Arnheim's entropy theory. Numerous other European theoreticians of Art Informel and Abstract Expressionism, such as Cirlot, Haftmann, Ragon, Restany, and others, are also mentioned. In addition, a short overview is provided of the time immediately preceding Art Informel, that is the socio-political situation and the attitude towards abstract art in Croatia and Yugoslavia during the 1950s and 1960s and towards the emergence of Informalism in the Yugoslav art scene. The second chapter deals with the emergence, reception, interpretation, and definitions of radical Art Informel. The heterogeneity of Informalist painting in Croatia encouraged Ješa Denegri, during the first significant retrospective of Art Informel in 1977, to develop the hypothesis of two disparate sides of Art Informel – the radical and pictorial type. Other divisions of Art Informel are also provided in this chapter, as well as critiques of the theory on radical Informalism and the conception of Informalist painting in a somewhat limited classification such as this. Over time, the notion of radical and materic Art Informel also became rooted within the annals of Croatian art, as is visible in newer systematizations of Croatian art of the 20th century. The third chapter of this thesis provides insights into Informalist art of the main protagonists of Art Informel and those artists who, through individual works, were brought closer to them by adopting similar practices and created artworks of similar morphological stylistic characteristics or shared the same opinions, ideologies, and viewpoints on art. In the subchapters that cover the diction of individual artists, a comparison is provided between specific examples of artworks that point to the similarities and differences between works of artists from Europe and around the globe, and those of the aforementioned protagonists of Croatian radical Art Informel. The fourth chapter is dedicated to the examination of radical Art Informel in the context of Yugoslavia, as well as to comparisons with the emergence of Art Informel in other countries (Serbia, Slovenia, Montenegro, North Macedonia, Bosnia and Herzegovina) with a particular emphasis on the differences and similarities of Informalism in Zagreb and Belgrade. Art Informel in Belgrade stands out because its critical and theoretical interpretations were clearly expressed even in the 1960s, at the time of the development of Art Informel, and primarily through the endorsing exhibition Young Painters of Belgrade as far back as 1962. Also, it had created a contentious atmosphere from the very start and was accompanied by numerous texts and reviews by the Serbian art historian and art critic Lazar Trifunović, who was a big proponent of Belgrade Art Informel. Art Informel in Croatia is an extremely complex and heterogeneous artistic phenomenon. Alongside general characteristics of Art Informel - the abolishment of traditional conceptions of composition and painting, the dissolution of mimesis, the use of free organic forms, and the use of non-painterly materials and procedures - all of these characteristics are even more pronounced in radical Informalism. In the morphological sense, they are embodied in an ever more pronounced materiality, reliefness (texturedness), formlessness, monochromatic and achromatic color registers, the use of raw materials, their coming into being through destructive, deforming processes such as carving, scratching, accumulating structures and masses, fragmenting, removing layers and burning, as well as in the representatives’ views on art: the negation of painting, a leaning towards anti-art, self-referencing, nonpicturality, nonsemanticity, nihilism, and a brutal aesthetic. The radical variant or type of Art Informel in Croatian art can also be called materic painting, materiologic or perhaps nonsemantic Informalism. This thesis provides insights into the differing contexts of radical Art Informel; from stylistic-morphological interpretations, theoretical-critical interpretation, the sociopolitical context, the aesthetics of anti-painting and the phenomenology of processuality, to scrutinizing the emergence of radical Art Informel within the discourse of gender theory
Istraživanje trovalentnih titanata rijetkih zemalja lokalnim probama
No full textThis thesis contains an in-depth experimental investigation of trivalent rare-earth titanates. Titanates are a model system for exploring intricate interactions between spin, orbital, and lattice degrees of freedom. These compounds belong to a broader family of transition metal oxides. Their ground state can be easily manipulated by strain, chemical, and charge doping, offering a unique opportunity to explore the Mott insulator phase and metal-insulator transitions. One of the foremost open questions is the orbital state of titanates which we try to resolve with this thesis. We present a detailed nuclear magnetic resonance (NMR) and electron spin resonance (ESR) study of single-crystalline samples of (Y,Ca,La)TiO_3 in a wide range of isovalent substitution (La) and hole doping (Ca). 89^Y NMR demonstrates a clear discrepancy between the static and dynamic local magnetic susceptibilities, with deviations from Curie-Weiss behavior far above the Curie temperature _. ESR of the unpaired Ti electron shows broad resonance lines at all temperatures and substitution/doping levels, which we find to be caused by short electron spin-lattice relaxation times. Modeling of the relaxation as an Orbach process revealed a small gap likely produced by Jahn-Teller splitting of the two lower Ti _2 orbitals. We find that the value of the gap closely follows _ and is consistent with the temperatures at which deviations from Curie-Weiss fluctuations are observed in NMR. These results indicate that full orbital degeneracy lifting is associated with ferromagnetic order. Ferromagnetic resonance with orientational dependence on the three primary YTiO_3 axes was successfully measured and modeled. Free energy description of the data revealed values for the parameters reflecting the inherent magnetocrystalline anisotropy. Furthermore, we present measurements of uniaxial strain on a range of (Y,Ca,La)TiO_3 single crystals and its influence on the bulk ferromagnetism. The results demonstrate direct, reversible and continuous control of ferromagnetism by influencing the TiO6 octahedral tilts and rotations. Ab initio calculations, provided by our collaborators, agree well with the experimental data and offer a better understanding of the complex interactions among structural, orbital and magnetic properties that drive the physics of rare-earth titanates.Rezultati ovog rada daju jedinstven i detaljan uvid u lokalne interakcije u titanatima rijetkih zemalja. Mjerenja lokalnih statičkih i dinamičkih susceptibilnosti s pomoću reix zonantnih tehnika upotpunjavaju fazni dijagram ne samo stehiometrijskog spoja YTiO_3, već i čvrstih otopina Y(Ca,La)TiO_3 na kojima do sada nije bilo eksperimentalnih rezultata. Pokazali smo da postoje anomalna ponašanja u paramagnetskoj fazi titanata, koja se posebno očituju u relaksacijskim mjerenjima detektiranim NMR tehnikom. Snažna divergencija relaksacije 1/_2 na temperaturama ≈ 70K nije objašnjena, što upućuje na potrebu boljeg razumijevanja važnosti mehanizma relaksacije spin-spin u titanatima i srodnim oksidima prijelaznih metala. Jedinstven uvid u orbitalno stanje titanata dobili smo mjerenjem elektronske spinske rezonancije. Potvrdili smo postojanje malog procjepa između najnižih nivoa _2 orbitala te utvrdili jasnu vezu s feromagnetizmom ovih spojeva. Naši rezultati potvrđuju važnost blagih Jahn-Tellerovih deformacija oktaedara za bolje razumijevanje kompleksnih interakcija u jakokoreliranim elektronskim sustavima. Ovim radom ističemo važnost korištenja rezonantnih tehnika pri istraživanju oksida prijelaznih metala. Nadalje, originalnim eksperimentom uniaksijalnog naprezanja potvrdili smo teorijska predviđanja o utjecaju kontrolirane kompresije na magnetsko osnovno stanje. Naši rezultati, uz dobro slaganje s teorijskim modelom, dali su uvid u točne distorzije rešetke koje pospješuju FM i AFM vezanja u titanatima. Ovaj jedinstveni eksperiment daje snažan poticaj za mogućnost inženjerstva željenih svojstava u materijalima s pomoću naprezanja
Specific effects of ions on the formation and properties of poly(allylamine hydrochloride)/poly(acrylic acid) multilayer
No full textPolielektrolitni kompleksi i višeslojevi poli(alilamin-hidroklorida) i poli(akrilne kiseline) pripravljeni su u vodenim otopinama NaF, NaCl, NaClO4, LiCl i (CH3)4NCl. Nastanak polielektrolitnih kompleksa po prvi puta istražen je visoko-razlučivom ultrazvučnom spektroskopijom. Ovom metodom ustanovljeno je da interpolielektrolitna neutralizacija rezultira ion-specifičnom agregacijom nabijenih koloidnih kompleksa. Analogan utjecaj iona određen je u slučaju odgovarajućih višeslojeva. Elipsometrom i mikroskopom atomskih sila utvrđeno je da debljina i hrapavost filma raste u nizu F− < Cl− < ClO4− za anione odnosno (CH3)4N+ < Na+ < Li+
za katione. Nadalje, ustanovljeno je da hidrofobnost višesloja također slijedi opisani trend za anione kada je polikation završni sloj filma. Zagrijavanjem polielektrolitnih višesloja tijekom njihove priprave potisnut je specifičan utjecaj iona na površinsku hrapavost i močivost zbog reorijentacije i migracije polimernih lanaca na međupovršini višesloj/zrak. Naposlijetku, provedeno istraživanje ukazuje na značajnu korelaciju između procesa interpolielektrolitne neutralizacije u otopini i na površini.Polyelectrolyte complexes and multilayers of poly(allylamine hydrochloride) and poly(acrylic acid) were prepared in aqueous solutions of NaF, NaCl, NaClO4, LiCl, and (CH3)4NCl. The formation of polyelectrolyte complexes was investigated for the first time by high-resolution ultrasonic spectroscopy. Using this method, it was established that interpolyelectrolyte neutralization results in ion-specific aggregation of charged colloidal complexes. Analogous influence of ions was observed in the case of corresponding multilayers. Using ellipsometer and atomic force microscope, it was determined that the thickness and roughness of the film increases in the sequence F− < Cl− < ClO4− for anions and (CH3)4N+ < Na+ < Li+ for cations. Furthermore, it was found that the hydrophobicity of the multilayer also follows the described trend for anions when a polycation is terminating layer of the film. By heating polyelectrolyte multilayers during their preparation, the specific influence of ions on surface roughness and wettability was suppressed due to the reorientation and migration of polymer chains at the multilayer/air interface. Finally, the conducted research indicates a significant correlation between the process of interpolyelectrolyte neutralization in solution and on the surface
Uloga otvorenih inovacija i apsorpcijskog kapaciteta u uspješnosti razvoja novih proizvoda i usluga u Republici Hrvatskoj
No full textGlobalization, digital transformation, and market shocks have revealed the importance of new product development when it comes to enabling companies to remain competitive in the market, maintain customer relationships, and achieve successful collaboration with external partners through open innovation (OI) activities. OI involves inbound (IOI) and outbound (OOI) activities, and it implies that a company is ready to open up their organizational borders and share their knowledge with external partners (Chesbrough, 2003). The implementation of OI activities allows companies to adapt to rapid market changes by granting them access to diverse partners and enabling them to integrate external resources. However, without proper knowledge management and knowledge absorption, new technologies may remain unused. Following the concept of absorptive capacity (AC), which refers to learning from external sources of knowledge through potential (PAC) and realized (RAC) absorptive capacity, doctoral dissertation is guided by the assumption that high levels of AC will mediate the relationship between OI and new product development performance (NPDP). Doctoral dissertation uses a combination of partial least squares structural equation modeling (PLS-SEM) and fuzzy-set qualitative comparative analysis (fsQCA) to examine four main hypotheses. Building on the sample of 112 top and middle level managers in digitally mature Croatian companies, the following conclusions were made.
Managers are encouraged to motivate their employees to use information inside and outside of their industry and to communicate ideas and problems with employees working outside the R&D sector in order to increase their PAC. The results show that seeking external ideas and collaborating with external partners through IOI will not automatically impact NPDP, meaning that technologies and ideas could remain unused if employees do not understand or are not willing to use and share knowledge. Additionally, managers are encouraged to motivate employees to acquire new knowledge and connect it with existing knowledge as well as to apply it into their businesses to increase RAC. The results show that managing outward flows of knowledge and selling intellectual property and technological knowledge through OOI activities will not directly influence NPDP, but that the relationship is fully mediated through RAC. Findings from the systematic literature review, bibliographic mapping, PLS-SEM, and fsQCA expand the theoretical background on the role of OI and AC in NPDP, while the practical implications for managers are helpful in enabling decision-makers to develop strategies, especially for digitally mature companies.U doba globalizacije, digitalne transformacije, ali i sve češćih tržišnih šokova poput pandemije, rata i prirodnih nepogoda, dodatno je istaknuta važnost razvoja novih proizvoda i usluga kako bi poduzeća ostala konkurentna na tržištu, zadržala postojeće kupce te ostvarila uspješnu suradnju s partnerima (Marzi et al., 2021; Obradović et al., 2021). Suradnja među partnerima izdvojena je kao jedan od temeljnih ciljeva održivog razvoja Ujedinjenih naroda za 2030. godinu (UN General Assembly, 2015). Dodatno, suradnja između industrije i akademske zajednice putem aktivnosti otvorenih inovacija, nalazi se među glavnim ciljevima politike za istraživanje i inovacije Europske unije (European Commission, 2015). Otvorene inovacije podrazumijevaju spremnost poduzeća za otvaranje svojih organizacijskih granica te dijeljenje i prijenos znanja unutar i izvan poduzeća, a sastoje se od ulaznih (engl. inbound) i izlaznih otvorenih inovacija (engl. outbound) (Chesbrough, 2003). Ulazne otvorene inovacije podrazumijevaju aktivnosti poput traženja vanjskih ideja kako bi se stvorila dodatna vrijednost za poduzeće, kontaktiranja vanjskih dionika kako bi se stekla nova tehnološka znanja te poboljšala vlastita proizvodnja ili ostvarivanja većeg broja suradnji s vanjskim dionicima kako bi se stvorilo međusobno povjerenje (Hung i Chou, 2013; Arias-Pérez et al., 2021). Izlazne otvorene inovacije odnose se na aktivno upravljanje protokom znanja prema vanjskim partnerima te prodaju tehnološkog znanja ili intelektualnog vlasništva na tržištu (Hung i Chou, 2013; Arias-Pérez et al., 2021).
Za poduzeća koja su implementirala aktivnosti ulaznih i izlaznih otvorenih inovacija, nužno je da njeguju kulturu otvorenosti te da pravodobno upravljaju novostečenim, ali i postojećim znanjem (Dabić et al., 2019). Iz koncepta apsorpcijskog kapaciteta koji je definiran kao „sposobnost učenja iz vanjskih izvora znanja kroz procese identifikacije, integracije i iskorištavanja znanja“ (Cohen i Levinthal 1989., str. 569), proizlazi da će zaposlenici i menadžeri locirati i vrednovati znanje koje je stečeno izvan vlastitog poduzeća putem aktivnosti otvorenih inovacija. Zahra i George (2002) naglašavaju važnost apsorpcijskog kapaciteta kao dinamičke sposobnosti poduzeća te ga dijele na potencijalni apsorpcijski kapacitet koji obuhvaća usvajanje i integriranje znanja te realizacijski apsorpcijski kapacitet koji obuhvaća transformiranje i iskorištavanje znanja. Na temelju dosadašnje literature, doktorski rad polazi od pretpostavke kako će suradnja s vanjskim partnerima kroz ulazne i izlazne otvorene inovacije, doprinijeti novim izvorima znanja te potaknuti daljnje usvajanje, integriranje, transformiranje i iskorištavanje znanja kroz potencijalni i realizacijski apsorpcijski kapacitet, a koje će posljedično utjecati na uspješnost razvoja novih proizvoda i usluga u digitalno zrelim hrvatskim poduzećima. Pod digitalno zrelim poduzećima podrazumijevaju se ona poduzeća koja su implementirala digitalne tehnologije poput interneta stvari, analitike velikih podataka, proširene stvarnosti i drugih u svom poslovanju (Tortorella et al., 2019).
Glavni cilj doktorskog rada je kritički evaluirati postojeće znanstvene spoznaje te razviti model za testiranje posredničke uloge apsorpcijskog kapaciteta u odnosu otvorenih inovacija i uspješnosti razvoja novih proizvoda i usluga. Dodatno, cilj je pružiti nove spoznaje o primijenjenim konstruktima i njihovoj povezanosti. Istraživanje je provedeno na uzorku 112 menadžera srednje i visoke razine u digitalno zrelim hrvatskim poduzećima različitih industrija i veličina. Prema europskoj ljestvici uspjeha u inoviranju, Republika Hrvatska pripada skupini inovatora u nastajanju te je okarakterizirana kao regija s učinkom ispod 70% od prosjeka Europske unije (European Commission, 2021). U teorijskom dijelu rada proveden je sustavni pregled literature koji je omogućio analizu trenutnog stanja područja otvorenih inovacija, apsorpcijskog kapaciteta te uspješnosti razvoja novih proizvoda i usluga. U empirijskom dijelu rada, ispitan je odnos između otvorenih inovacija i uspješnosti razvoja novih proizvoda, uz posredničku ulogu apsorpcijskog kapaciteta. Prikupljeni podaci iz anketnog upitnika analizirani su metodama strukturalnog modeliranja jednadžbi najmanjim djelomičnim kvadratima (PLS-SEM) i kvalitativno komparativnom analizom – metoda neizrazitih skupova (fsQCA). PLS-SEM metoda je omogućila ispitivanje direktnih i indirektnih odnosa između nezavisnih varijabli (ulazne i izlazne otvorene inovacije, potencijalni i realizacijski apsorpcijski kapacitet) i zavisne varijable (uspješnosti razvoja novih proizvoda), dok su uz pomoć fsQCA metode formulirani nužni i dovoljni uvjeti za uspješnost razvoja novih proizvoda te se produbilo razumijevanje utjecaja različitih kombinacija nezavisnih varijabli koje vode uspješnosti razvoja novih proizvoda.
Rezultati PLS-SEM analize pokazuju kako ulazne otvorene inovacije pozitivno utječu na potencijalni apsorpcijski kapacitet, ali nije dokazana značajnost utjecaja na realizacijski apsorpcijski kapacitet. S druge strane, izlazne otvorene inovacije pozitivno utječu i na potencijalni i realizacijski apsorpcijski kapacitet. Nadalje, potencijalni apsorpcijski kapacitet ima pozitivan utjecaj na realizacijski apsorpcijski kapacitet što je u skladu s dosadašnjim istraživanjima (García-Sánchez et al., 2018; Limaj i Bernroider, 2019). Rezultati pokazuju kako potencijalni i realizacijski apsorpcijski kapacitet pozitivno utječu na uspješnost razvoja novih proizvoda i usluga, iako je utjecaj realizacijskog apsorpcijskog kapaciteta značajniji. Rezultati testiranja hipoteze medijacijskog učinka pokazuju kako potencijalni apsorpcijski kapacitet posreduje odnos između ulaznih otvorenih inovacija i uspješnosti razvoja novog proizvoda i usluga, dok realizacijski apsorpcijski kapacitet posreduje odnos između izlaznih otvorenih inovacija i uspješnosti razvoja novog proizvoda i usluga. S druge strane, nije potvrđena medijacijska uloga potencijalnog apsorpcijskog kapaciteta u odnosu između izlaznih otvorenih inovacija i uspješnosti razvoja novog proizvoda i usluga kao ni medijacijska uloga realizacijskog apsorpcijskog kapaciteta u odnosu između ulaznih otvorenih inovacija i uspješnosti razvoja novog proizvoda i usluga.
Rezultati fsQCA metode pokazuju kako ulazne otvorene inovacije, izlazne otvorene inovacije, potencijalni apsorpcijski kapacitet i realizacijski apsorpcijski kapacitet, kao zasebne varijable ne predstavljanju nužne uvjete, dok njihove kombinacije pozitivno utječu na uspješnost razvoja novog proizvoda. Analiza implicira kako kombinacija ulaznih otvorenih inovacija, potencijalnog i realizacijskog apsorpcijskog kapaciteta, neovisno o odsutnosti izlaznih otvorenih inovacija, vodi višim razinama uspješnosti razvoja novih proizvoda. Dodatno, kombinacija izlaznih otvorenih inovacija, potencijalnog i realizacijskog apsorpcijskog kapaciteta, neovisno o odsutnosti ulaznih otvorenih inovacija, ostvaruje višu razinu uspješnosti. Zaključuje se kako je za poduzeće nužno da razvija i njeguje apsorpcijski kapacitet, jer bez obzira na suradnju s vanjskim partnerima, ukoliko poduzeće ne upravlja znanjem te pravovremeno ne povezuje novonastalo znanje s postojećim, tehnološko znanje može ostati neiskorišteno.
Model utjecaja otvorenih inovacija na uspješnost razvoja novih proizvoda i usluga u digitalno zrelim poduzećima koji obuhvaća medijacijsku varijablu apsorpcijskog kapaciteta doprinosi razvoju metodologije. Rezultati istraživanja upućuju na različitu medijacijsku ulogu potencijalnog i realizacijskog apsorpcijskog kapaciteta u odnosu između ulaznih i izlaznih otvorenih inovacija i uspješnosti razvoja novih proizvoda i usluga. Znanstveni doprinos doktorskog rada očituje se u kritičkoj evaluaciji teorije kroz sustavni pregled literature koji upućuje na zaključak kako autori istražuju utjecaj suradnje vanjskih partnera (kupaca, dobavljača, sveučilišta) na razvoj novog proizvoda (Santoro et al., 2017; Wu et al., 2022). Dodatno, rezultati bibliometrijske analize ukazuju na buduće pravce razvoja teorije kroz istraživanje uloga naprednih tehnologija industrije 4.0 koje omogućavaju prikupljanje vrijednih podataka (internet stvari, analiza velikih podataka, umjetna inteligencija) na razmjenu znanja između vanjskih partnera. Razmjena iskustva i tehnologije nadalje omogućava menadžerima razvoj nužnih sposobnosti i kompetencija, smanjenje troškova te održivu proizvodnju.
Na temelju rezultata PLS-SEM i fsQCA analize te sustavnog pregleda literature i bibliometrijske analize, doktorski rad implicira sljedeće preporuke za donositelje odluka u digitalno zrelim poduzećima. Menadžeri srednje i visoke razine se potiču na a) motiviranje svojih zaposlenika za korištenjem informacija unutar i izvan svoje industrije te b) komuniciranje ideja i problema sa zaposlenicima koji rade izvan sektora istraživanja i razvoja. Na taj će način menadžeri povećati potencijalnu apsorpcijsku sposobnost, odnosno sposobnost poduzeća da prepozna i usvoji znanje stečeno izvan vlastitog poduzeća. Rezultati su pokazali kako traženje vanjskih ideja i suradnja s vanjskim partnerima kroz ulazne OI neće automatski utjecati na uspješnost razvoja novih proizvoda i usluga, odnosno kako će tehnologije i ideje ostati neiskorištene ako zaposlenici ne razumiju ili nisu voljni koristiti i dijeliti znanje. Štoviše, menadžere se potiče na c) motiviranje zaposlenika prema usvajanju novih znanja, d) povezivanju znanja koja već postoje unutar poduzeća s novostečenim znanjima i primjeni u poslovanju. Na taj način menadžeri povećavaju realizacijski apsorpcijski kapacitet, odnosno sposobnost poduzeća da unaprijedi svoje prakse na temelju novostečenih znanja. Rezultati su pokazali kako aktivnosti upravljanja vanjskim tokovima znanja i prodaja intelektualnog vlasništva i tehnološkog znanja kroz izlazne OI neće izravno utjecati na uspješnost razvoja novih proizvoda i usluga, već da je odnos u potpunosti posredovan kroz realizacijski apsorpcijski kapacitet. Ukratko, rezultati su istaknuli posredničku ulogu apsorpcijskog kapaciteta kao dinamičke sposobnosti poduzeća u odnosu između otvorenih inovacija i uspješnosti razvoja novih proizvoda i usluga u digitalno zrelim hrvatskim poduzećima.
Ograničenje doktorskog rada proizlazi iz mjerenja varijable uspješnosti razvoja novih proizvoda kroz subjektivnu percepciju menadžera koja je omogućila usporedbu dobivenih rezultata iz poduzeća različiti veličina i industrija. Daljnja istraživanja bi se trebala usmjeriti na specifične mjere uspješnosti poduzeća, posebice kroz prodaju, dobit, troškove te brzinu razvoja proizvoda. Nadalje, rezultati istraživanja su analizirani na temelju uzorka od 112 menadžera srednje i visoke razine u digitalno zrelim hrvatskim poduzećima. Buduća istraživanja mogu doprinijeti razvoju teorije kroz uključivanje ostalih zaposlenika koji su sudjelovali u procesu razvoja novih proizvoda, ali i kroz istraživanje na organizacijskoj razini. Iako je analiza provedena u Republici Hrvatskoj, model istraživanja te istraživačka pitanja mogu se generalizirati i za druga poduzeća koja posluju u sličnim razvojnim okruženjima, a posebice u zemljama koje su okarakterizirane kao inovatori u nastajanju (na primjer Rumunjska, Bugarska, Latvija, Poljska, Slovačka te Mađarska). Doktorski rad završava s preporukama za donositelje odluka u digitalno zrelim poduzećima, znanstvenike te društvo u cjelini
Kinetic analyisis of copper ions sorption on zeolite NaX in a batch reactor under different hydrodynamic conditions : doctoral thesis
No full textSažetak Zeoliti su mikroporozni kristalni alumosilikati koji su svojom primjenom kao katalizatori i sorbensi promijenili petrokemijsku i kemijsku industriju. Katalitička svojstva zeolita mogu se prilagoditi „umetanjem” iona teških metala u zeolit, a jedna od metoda koja se može koristiti za pripremu katalizatora je sorpcija. Sorpcija na zeolitima koristi se i za uklanjanje metala iz kontaminiranih voda. Ako se proces sorpcije vodi u kotlastom (šaržnom) reaktoru njegova učinkovitost ovisi o različitim procesnim parametrima, uključujući i parametre miješanja, a čiji utjecaj na samu sorpciju još uvijek nije dovoljno istražen. Hidrodinamički uvjeti u određenom sustavu posljedica su geometrijskih karakteristika reaktora i korištenog miješala te brzine vrtnje miješala. Stoga je u ovom radu ispitan utjecaj hidrodinamičkih uvjeta u reaktoru na učinkovitost i kinetiku sorpcije bakrovih iona na sintetskom zeolitu NaX u otvorenom šaržnom reaktoru s razbijalima virova. Miješanje se provodilo upotrebom triju različitih tipova miješala: aksijalnog propelerskog miješala, radijalno-aksijalnog turbinskog miješala s ravnim lopaticama nagnutim pod kutom (PBT) i radijalnog turbinskog miješala s ravnim lopaticama (SBT). Za sve tipove miješala sagledan je utjecaj tipa miješala te masene koncentracije zeolita NaX u otopini na kritičnu brzinu vrtnje miješala za postizanje stanja potpune suspenzije, N JS , kao i na kinetiku i na učinkovitost sorpcije bakrovih iona na zeolitu NaX. Pri najnižoj ispitivanoj masenoj koncentraciji suspenzije zeolita NaX u otopini, za sve tipove miješala, ispitan je utjecaj brzine vrtnje miješala, N/N JS , na provedbu ispitivanog procesa. Za PBT tip miješala je ispitan i utjecaj pozicije i promjera miješala na kinetiku i na učinkovitost ispitivanog procesa pri najnižoj ispitivanoj masenoj koncentraciji zeolita NaX u otopini. Procjena kinetičkih parametara provedena je nelinearnom i linearnom regresijskom analizom za tri kinetička modela: Ritchiejev model, Miješani kinetički model adsorpcije kontrolirane površinskom reakcijom i difuzijom (Miješani model) te Weber-Morrisov model. Kinetičkom analizom dobivenih eksperimentalnih podataka odabranim kinetičkim modelima utvrđeno je koji kinetički model najprikladnije opisuje kinetiku sorpcije bakrovih iona na zeolitu NaX te su izračunati kinetički parametri. Budući da je sorpcija heterogeni proces određen je i najsporiji korak procesa za ispitivane uvjete. Analizom eksperimentalnih kinetičkih podataka utvrđeno je da sorpciju bakrovih iona na zeolitu NaX najpotpunije opisuje Ritchiejev model. Međutim, pri brzinama vrtnje propelerskog i SBT miješala N/N JS od 0,60 i 0,80, Miješani model se bolje slaže s eksperimentalnim kinetičkim podatcima, sugerirajući da je reakcija drugog reda ograničena difuzijom. Da bi se dobio potpuniji uvid u hidrodinamička zbivanja u ispitivanom sustavu, uporabom programskog paketa ANSYS Fluent v17.2 simulirani su tokovi fluida. S obzirom na kinetiku i količinu sorbiranih bakrovih iona predložena je najpovoljnija geometrija reaktora.Abstract Zeolites are microporous crystalline aluminosilicates that have transformed the petrochemical and chemical industries through their use as catalysts and sorbents. The catalytic properties of zeolites can be altered by introducing heavy metal ions into the zeolite, and one of the methods used to prepare catalysts is sorption. Sorption on zeolites can also be used to remove metals from contaminated water. If the sorption process is carried out in a batch reactor, its efficiency depends on various process parameters, including the mixing parameters, the influence of which on sorption itself has not been sufficiently studied. The hydrodynamic conditions in a given system result from the geometrical characteristics of the reactor and the impeller used, as well as from the impeller rotation speed. For this reason, the influence of hydrodynamic conditions on the efficiency and kinetics of copper ions sorption on synthetic zeolite NaX in an uncovered batch reactor with baffles was studied in this work. Mixing was performed using three different impeller types: an axial propeller impeller, a radial-axial pitched blade turbine impeller (PBT), and a radial straight blade turbine impeller (SBT). For all impeller types, the effect of impeller type and zeolite NaX mass concentration in a solution on the critical impeller speed required to achieve a state of complete suspension, N JS , was investigated. The effect of impeller type on the kinetics of copper ions sorption on zeolite NaX and removal efficiency was studied. At the lowest mass concentration of NaX zeolite in the solution investigated, the effect of the impeller rotation speed, N/N JS , on the performance of the studied process was also investigated for all impeller types. For the PBT impeller, the effect of the impellers' position and its diameter on the kinetics of the copper ion sorption process on zeolite NaX and the removal efficiency at the lowest mass concentration of NaX zeolite in the solution investigated, were studied too. Kinetic parameter estimation was performed using nonlinear and linear regression analysis for three kinetic models: Ritchie’s model, Mixed kinetic model of adsorption controlled by surface reaction and diffusion (Mixed model), and Weber-Morris model. By kinetic analysis of the obtained experimental data using the selected kinetic models, a kinetic model that describes the kinetics of sorption of copper ions onto zeolite NaX, and the kinetic parameters were calculated. Since sorption is a heterogeneous process, the slowest step of the process was defined for the conditions studied. By analysing the experimental kinetic data, it was found that the sorption of copper ions onto zeolite NaX is well described by the Ritchie’s model. However, at impeller speeds of N/N JS 0.60 and 0.80, the Mixed model agrees better with the experimental kinetic data, suggesting that the second order reaction is suppressed by diffusion. To obtain a more complete insight into the hydrodynamic processes in the studied system, the fluid flows were simulated using the ANSYS Fluent v17.2 software package. Taking into account the obtained results, i.e. the kinetics and the amount of sorbed copper ions, the most favourable reactor geometry was proposed
Epistemological and didactic analysis of the notion of a polynomial
No full textPolinom kao jedan od najfundamentalnijih pojmova u gotovo svim područjima matematike, ima istaknutu ulogu u predtercijarnom i tercijarnom matematičkom obrazovanju. Upravo to ga kvalificira da bude idealan objekt institucijskog i epistemološkog istraživanja o didaktičkim procesima. Potreba za takvim istraživanjem inducirana je: 1. na globalnoj razini, malobrojnim istraživanjima u kojima je polinom glavni objekt istraživanja te neodgovorenim pitanjima o razlozima različitog načina definiranja pojma polinoma u predtercijarnom obrazovanju [13,221]; 2. na lokalnoj razini, recentnim promjenama u znanju za podučavanje u predtercijarnom obrazovanju i mogućim efektima tih promjena na tercijarno obrazovanje. Odabrani teorijski okvir, Antropološka teorija didaktike (ATD), nudi alate koji omogućavaju istraživanje epistemoloških i institucijskih aspekata znanja za podučavanje. Stoga se alatima ATD-a analizira tranzicija prema studiju matematike, kroz studij, kao i inverzna tranzicija, ona koju nastavnici matematike prolaze kada počinju podučavati matematiku u predtercijarnom obrazovanju. Dakle, analizira se dvostruki Kleinov prekid i tranzicija kroz studij matematike s obzirom na pojam polinoma. Pojam matematičke prakseologije koristi se za modeliranje i analiziranje matematičkih sadržaja i aktivnosti. Diseminacija matematičkih prakseologija analizira se i modelira pojmom didaktičke prakseologije. Didaktička transpozicija, koja je istodobno alat i metodologija, omogućava analiziranje znanja unutar obrazovnih institucija u odnosu na znanje discipline matematike. Prvo se analiziraju geneza i razvoj pojma polinoma u disciplini matematike, tj. razvoj znanja o pojmu polinoma koja epistemološki legitimiraju znanja koja se podučavaju u predtercijarnim i tercijarnim obrazovnim institucijama. Uzima se u obzir i reforma Nove matematike koja je inducirana promjenom u disciplini matematike. Posebno se istražuje realizacije reforme u hrvatskom gimnazijskom obrazovnom sustavu, kao i njeni rudimenti i mogući efekti na aktualni obrazovni sustav. Dokumenti koji propisuju znanje za podučavanje u hrvatskom predtercijarnom obrazovanju podvrgnuti su prakseološkoj analizi, kao i najkorišteniji gimnazijski udžbenici u zadnjih dvadesetak godina, kako bi se dobio uvid u sekundarno-tercijarnu tranziciju (prvi Kleinov prekid) od kad je uveden Bolonjski proces. S obzirom na pojam polinoma, analizira se obrazovanje matematičara i nastavnika matematike na Prirodoslovno-matematičkom fakultetu Sveučilišta u Splitu. Promatra se i mogući efekti drugog Kleinov prekida na buduće nastavnike matematike.The polynomial, as one of the most fundamental notions in almost all areas of mathematics, has a prominent role in pre-tertiary and tertiary mathematics education. That qualifies it to be an ideal object of institutional and epistemological research on didactic processes. The need for such research was induced by: 1. at the global level, the few studies in which the polynomial is the main object of research, and the unanswered questions about the reasons for the different ways of defining the notion of a polynomial in pre-tertiary education [13,221]; 2. at the local level, recent changes in knowledge for teaching in Croatian pre-tertiary mathematics education and the possible effects of these changes on university mathematics education. The selected theoretical framework, the Anthropological Theory of the Didactic (ATD), offers tools that enable the investigation of epistemological and institutional aspects of knowledge for teaching. Therefore, ATD tools are used to analyse the transition towards the study of mathematics, through the study, as well as the inverse transition, the one that mathematics teachers go through when they start teaching mathematics in pre-tertiary education. Thus, Klein’s double discontinuity, and transition through the study of mathematics, are analysed concerning the notion of a polynomial. A mathematical praxeology is a tool that is used for modelling and analysing mathematical contents and activities. The dissemination of mathematical praxeologies is analysed and modelled by the notion of a didactic praxeology. A didactic transposition, which is both a tool and a methodology, enables the analysis of knowledge within educational institutions concerning the knowledge of the discipline of mathematics. First, the genesis and development of the notion of a polynomial in the discipline of mathematics are analysed, i.e. the development of the knowledge about the notion of a polynomial that epistemologically legitimises the knowledge taught in pre-tertiary and tertiary educational institutions. The reform of New Mathematics, which was induced by a change in the discipline of mathematics, is also taken into account. The implementation of the reform in the Croatian high school education system is especially investigated, as well as its rudiments and possible effects on the current education system. Documents prescribing knowledge for teaching in Croatian pre-tertiary education were subjected to praxeological analysis, as well as the most used secondary textbooks in the last twenty years, as would gain an insight into the secondary-tertiary transition (Klein’s first discontinuity) since the Bologna process was introduced. The education of mathematicians and mathematics teachers at the Faculty of Science, University of Split is analysed considering the notion of a polynomial. The possible effects of Klein’s second discontinuity on prospective pre-tertiary mathematics teachers are also observed
Acute effects of preconditioning activities with elastic rope on sprint, slalom and kicking performance in soccer players
No full textCilj: Brojni potencijacijski podražaji korišteni su u istraživanjima postaktivacijske potencijacije. Do sada za potencijacijski podražaj još nije korišteno elastični otpor u horizontalnom smjeru. Primarni je cilj kod nogometaša utvrditi ukupni akutni učinak sprinta sa elastičnim užetom na izvedbe sprinta, trčanja u slalomu i udarca po lopti te specifični akutni učinak s obzirom na dominantnosti horizontalnog mehaničkog profila. Sekundarni je cilj utvrditi razlike u izvedbama sprinta, slaloma i udarca prema dominantnosti u
horizontalnome mehaničkom profilu. Metode: U istraživanju je sudjelovalo 118 zdravih nogometaša iz sedam klubova Treće
hrvatske nogometne lige. Uključujući kriteriji za sudjelovanje u istraživanju bili su: (i) muški spol, stariji od 18 godina, (ii) minimalno 5 godina iskustva u nogometom treningu i natjecanju (iii) te da nisu pretrpjeli ozljedu donjih ekstremiteta u posljednjih 6 mjeseci. Svi ispitanici su proveli dva protokola zagrijavanja nakon kojih su izvodili testove. Protokoli zagrijavanja su se razlikovali samo u svom zadnjem dijelu. Na kraju jednog protokola se izvodio sprint 30 m, a na kaju drugoga sprint sa elastičnim užetom na maksimalnoj udaljenosti od hvatišta na kojoj ispitanik može napraviti jednak broj koraka kao i pri sprintu 30 m, a da ga uže ne povuče u nazad. Ispitanici su prije zagrijavanja ispunili upitnik za određivanje razine umora/oporavka. Sva istraživanja su provedena na prirodnoj travi na domicilnim terenima klubova koji su sudjelovali u istraživanju. Rezultati: Na ukupnom uzorku nogometaša (n=118) utvrđeno je pogoršanje izvedbe sprinta sa potencijacijskim podražajem između 0 i 5 metara (p<0,001; d=0,23; 1,36%), 20 i 25 metara (p=0,002; d=0,14; 0,67%) i 25 i 30 metara (p<0,001; d=0,35; 1,69%) te poboljšanje izvedbe slalom trčanja (p<0,001; d=0,38; 1,51%). Također, utvrđen je i pad horizontalnih mehaničkih parametara F0 (p=0,002; d=0,17; 2,00%), Pmax (p<0,001; d=0,20; 2,31%) i RFmax (p=0,002; d=0,19; 1,11%). Dvosmjernom mješovitom ANOVOM utvrđena je razlika u interakciji između protokola i grupa u sprintu između 0 i 5 metara (p=0,002; ηp 2=0,27; F=11,67), 5 i 10 metara (p=0,004; ηp 2=0,24; F=9,84), 15 i 20 metara (p=0,010; ηp 2=0,19; F=7,55), 20 i 25 metara (p=0,027; ηp 2=0,14; F=5,40) i 25 i 30 metara (p=0,014; ηp 2=0,18; F=6,79) te u brzini lopte kod udarca (p=0,049; ηp 2=0,51; F=4,19). Usporedbom parova kod grupe nogometaša dominantnih u teorijskoj maksimalnoj sili utvrđeno je pogoršanje izvedbe u sprintu između 0 i 5 metara (p=0,001; d=1,16; 4,5%) i poboljšanje izvedbe između 5 i 10 metara za (p=0,017; d=0,28; 1,26%). Poboljšanje je utvrđeno i u izvedbi slalom trčanja (p=0,007; d=0,59; 2,25%) kao i kod udarca (p=0,025; d=0,46; 2,88%). U horizontalnim mehaničkim parametrima utvrđen je pad F0 (p=0,001; d=0,94; 7,43%), Pmax (p<0,001; d=0,70; 6,37%) i RFmax (p=0,001; d=1,00; 3,59%) te povećanje V0 (p=0,001; d=0,33; 1,82%), DRF (p=0,002; d=0,89; 9,30%) i Vmax (p=0,020; d=0,29; 1,54%). Usporedbom parova kod grupe nogometaša dominantnih u teorijskoj maksimalnoj brzini utvrđeno je pogoršanje izvedbe u sprintu između 15 i 20 metara (p=0,035; d=0,67; 1,70%), 20 i 25 metara (p=0,022; d=0,69; 2,31%) i 25 i 30 metara (p=0,001; d=0,98; 3,37%), dok je kod slalom trčanja utvrđeno poboljšanje izvedbe (p=0,036; d=0,28; 1,04%). U horizontalnim mehaničkim parametrima utvrđen je pad V0 (p=0,002; d=0,69; 2,59%), DRF (p=0,020; d=0,36; 5, 50%) i Vmax (p=0,002; d=0,73; 2,44%). Grupa dominantna u maksimalnoj teorijsko sili je u sprintu brža na prvih 5 metara u oba protokola. U kontrolnom protokolu za 10,5% (p<0,001; d=2,25), a u potencijacijskom protokolu za 5,85% (p=0,004; d=0,96). Grupa dominantna u brzini je brža u svim preostalim dionicama po 5 metara u oba protokola. U kontrolnom protokolu od 5,11% do 6,31% (p<0,001; d=1,26 do 1,70), a u potencijacijskom protokolu od 2,6% do 4,11% (p=0,023 do <0,001; d=0,78 do 1,28). U izvedbi slalom testa grupa dominantna u sili je brža u potencijacijskom protokolu za 2,72% (p=0,025; d=0,69). Kod udarca grupa dominantna u brzini ima veću brzinu lopte u kontrolnom protokolu za 3,87% (p=0,042; d=0,59). Zaključak: Ovo istraživanje je pokazalo da je potencijacijski podražaj sprint sa horizontalnim elastičnim otporom značajno akutno poboljšava izvedbu trčanja u slalomu kod svih nogometaša, ali i specifično po grupama. To ukazuje da je potencijacijski podražaj vjerojatno poboljšao neuromuskularnu učinkovitost i reaktivnu sposobnost mišića. Potencijacijskim podražajem se značajno povećala maksimalna brzina lopte kod udarca i horizontalni mehanički parametri V0, DRF i Vmax samo kod nogometaša dominantnih u sili. To ukazuje na poboljšanu regrutaciju mišićnih vlakana i sinkronizaciju motoričkih jedinica nakon intenzivnog opterećenja. Potencijacijskim podražajem u prosjeku kod svih nogometaša dolazi do pogoršanja izvedbe na prvih 5 m i na zadnje dvije dionice po 5 m sprinta na 30 m, a kod dominantnih u sili samo prvih 5 m, dok kod dominantnih u brzini samo na zadnje tri dionice po 5 m. U prosjeku kod svih nogometaša potencijacijskim podražajem dolazi do pada F0, Pmax i RFmax, još veći pad navedenih parametara prisutan je kod grupe dominantne u sili, dok je kod grupe dominantne u brzini utvrđen pad V0, DRF i Vmax parametara. Pad performansi upućuje na zamor i neuromuskularnu inhibiciju, s većim utjecajem na početak sprinta kod dominantnih u sili te na kraj sprinta kod dominantnih u brzini.Objective: Lots of preconditioning activity have been used in studies of postactivation potentiation. So far, for the conditioning activity no one used an elastic resistance in the horizontal direction. The primary goal in soccer players is to determine the overall acute effect of sprinting with an elastic rope on the performance of sprinting, slalom running and kicking the ball, as well as the specific acute effect regarding the dominance of the horizontal mechanical profile. The secondary objective was to determine the differences in sprint, slalom and shot performance according to dominance in the horizontal mechanical profile.
Methods: 118 healthy soccer players from seven clubs of the Third Division Croatian Soccer League participated in the research. Inclusion criteria for participation in the study were: (i) male, older than 18 years, (ii) minimum 5 years of experience in soccer training and competition (iii) not having suffered an injury to the lower extremities in the last 6 months. All subjects performed two warm-up protocols, after which they performed tests. The warm-up protocols differed only in their last part. At the end of one protocol, a 30 m sprint was performed, and at the end of the second protocol was performed a sprint with an elastic rope at the maximum distance from the grip where the subject can take the same number of steps as during a 30 m sprint, without the rope pulling him back. Before the warm-up, the subjects filled out a questionnaire to determine the level of fatigue/recovery. All research were performed on natural grass at the home fields of the clubs that participated in the research.
Results: In the total sample of soccer players (n=118), a worsening in sprint performance with a potentiation stimulus between 0 and 5 meters (p<0.001; d=0.23; 1.36%), 20 and 25 meters (p=0.002; d=0.14; 0.67%) and 25 and 30 meters (p<0.001; d=0.35; 1.69%) and improvement in slalom running (p<0.001; d=0.38; 1.51%). Also, a decrease in the horizontal mechanical parameters F0 (p=0.002; d=0.17; 2.00%), Pmax (p<0.001; d=0.20; 2.31%) and RFmax was determined (p=0.002; d=0.19; 1.11%). Two-way mixed ANOVA revealed a difference in the interaction between protocol and groups in the sprint between 0 and 5 meters (p=0.002; ηp2=0.27; F=11.67), 5 and 10 meters (p=0.004; ηp2=0, 24; F=9.84), 15 and 20 meters (p=0.010; ηp2=0.19; F=7.55), 20 and 25 meters (p=0.027; ηp2=0.14; F=5, 40) and 25 and 30 meters (p=0.014; ηp2=0.18; F=6.79) and in the speed of the ball at soccer kick (p=0.049; ηp2=0.51; F=4.19). A pairwise comparison of a group of soccer players dominant in theoretical maximum force revealed a worsening of performance in the sprint between 0 and 5 meters (p=0.001; d=1.16; 4.5%) and improvement in performance between 5 and 10 meters by (p=0.017; d=0.28; 1.26%). Improvement was also found in the performance of slalom running (p=0.007; d=0.59; 2.25%) as well as in the soccer kick (p=0.025; d=0.46; 2.88%). A decrease in F0 (p=0.001; d=0.94; 7.43%), Pmax (p<0.001; d=0.70; 6.37%) and RFmax (p=0.001; d=1.00; 3.59%) was found in the horizontal mechanical parameters, but increase in V0 (p=0.001; d=0.33; 1.82%), DRF (p=0.002; d=0.89; 9.30%) and Vmax (p=0.020; d=0.29; 1.54%). By comparing pairs in the group of soccer players dominant in theoretical maximum velocity it was determined that the sprint performance worsening between 15 and 20 meters (p=0.035; d=0.67; 1.70%), 20 and 25 meters (p=0.022; d=0.69; 2.31%) and 25 and 30 meters (p=0.001; d=0.98; 3.37%), while an improvement in performance was found in slalom running (p=0.036; d=0.28; 1.04%). In horizontal mechanical parameters, a decrease in V0 (p=0.002; d=0.69; 2.59%), DRF (p=0.020; d=0.36; 5.50%) and Vmax (p=0.002; d=0.73; 2.44%). The group dominant in maximum theoretical force is faster in the sprint in the first 5 meters in both protocols. In the control protocol by 10.5% (p<0.001; d=2.25), and in the potentiation protocol by 5.85% (p=0.004; d=0.96). The group dominant in velocity is faster in all remaining sections of 5 meters in both protocols. In the control protocol from 5.11% to 6.31% (p<0.001; d=1.26 to 1.70), and in the potentiation protocol from 2.6% to 4.11% (p=0.023 to <0.001; d =0.78 to 1.28). In the performance of the slalom test, the force dominant group was faster in the potentiation protocol by 2.72% (p=0.025; d=0.69). In a soccer kick, the group dominant in velocity has a higher ball speed in the control protocol by 3.87% (p=0.042; d=0.59).
Conclusion: This research has shown that the potentiation stimulus sprint with horizontal elastic resistance significantly acutely improves the performance of running in slalom in all soccer players, but also specifically by groups. This indicates that the potentiation stimulus probably improved neuromuscular efficiency and muscle reactivity. The potentiation stimulus significantly increased the maximum speed of the ball at soccer kick and the horizontal mechanical parameters V0, DRF and Vmax only in force dominant group. This indicates improved recruitment of muscle fibers and synchronization of motor units after intense preconditioning activity. The potentiation stimulus causes, on average, a deterioration in the performance of all soccer players in the first 5 m and in the last two sections of a 5 m sprint on 30 m, and in those dominant in force only in the first 5 m, while in those dominant in velocity only in the last three sections of 5 m On average, in all soccer players, the potentiation stimulus causes a drop in F0, Pmax and RFmax, an even greater drop in the mentioned parameters is present in the force dominant group, while in the velocity dominant group, a drop in V0, DRF and Vmax parameters was found. The drop in performance points to fatigue and neuromuscular inhibition, with a greater impact on the beginning of the sprint in those dominant in force and at the end of the sprint in those dominant in velocity