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Digitalization of public administration and e-participation at the local level – the example of Međimurje County
No full textPrimarna usmjerenost istraživanja koja se bave digitalnom transformacijom rada javne uprave jest istražiti razinu implementacije digitalnih usluga i proizvoda na nacionalnim ili regionalnim razinama. U ovome radu naglasak se stavlja na povezanost digitalizacije rada javne uprave (engl. e-government) na lokalnoj razini te stupnja e-participacije građana lokalnih zajednica, a veza između ta dva fenomena definirana je s pet osnovnih ciljeva – identificirati opseg, iskustva i očekivanja od e-participacije građana lokalnih zajednica (te ispitati postoje li razlike s obzirom na sociodemografske karakteristike građana – spol, dob, stupanj obrazovanja i zanimanje); ispitati važnost i razinu korištenja dimenzija zrelosti e-uprave (prisutnost na internetu, interakcija, transakcija, potpuno integrirana i transformirana e-uprava te digitalna demokracija) na razini Međimurske županije; ispitati važnost i razinu korištenja dimenzija usmjerenosti e uprave (engl. citizens to government, government to citizens i citizens to citizens) na razini Međimurske županije; ispitati važnost i procjenu dimenzija kvalitete e-uprave (kvaliteta informacija, kvaliteta sustava, kvaliteta usluga) na razini Međimurske županije te identificirati specifične potrebe građana izučavane mikroregije po pitanju korištenja e-uprave (prednosti i barijere vezano uz njihovo korištenje). Istraživanje se provelo metodom anketnog upitnika u Međimurskoj županiji, jednoj od najrazvijenijih mikroregija Hrvatske u kojoj je javna uprava parcijalno digitalizirana te stoga predstavlja izvrstan slučaj za izučavanje odgovarajućih procesa u središtu istraživačkog interesa,. Uzorak je uključivao 351 ispitanika Međimurske županije po kvotama spola, dobi i stupnja obrazovanja. Rezultati su pokazali da postoji značajna povezanost između važnosti dimenzija zrelosti, usmjerenosti i kvalitete e-uprave i same razine e-participacije (mjera korištenja dimenzija zrelosti i usmjerenosti e-uprave) te značajna razlika u procjeni važnosti zrelosti, usmjerenosti i kvalitete e-uprave, u razini korištenja dimenzija zrelosti i usmjerenosti e-uprave te u razini e-participacije preko društvenih mreža s obzirom na spol, dob, razinu obrazovanja i složenost zanimanja.The primary focus of research on the digital transformation of public administration is to investigate the level of implementation of digital services and products at the national or regional levels. In this paper, the emphasis is placed on the connection between the digitalization of public administration (i.e., e-government) at the local level and the degree of e-participation by citizens in local communities. The connection between these two phenomena is defined by five basic goals: to identify the scope, experiences, and expectations of e participation among citizens in local communities (and to examine whether there are differences with regard to the socio-demographic characteristics of citizens, such as gender, age, level of education, and occupation); to examine the importance and level of use of the maturity dimensions of e-government (presence on the Internet, interaction, transaction, fully integrated and transformed e-government, and digital democracy) at the level of Međimurje County; to examine the importance and level of use of the dimensions of e-government orientation (i.e., citizens to government, government to citizens, and citizens to citizens) at the level of Međimurje County; to examine the importance and assessment of the quality dimensions of e government (quality of information, quality of systems, and quality of services) at the level of Međimurje County; and to identify the specific needs of the citizens in the studied microregion regarding the use of e-government (including advantages and barriers related to its use). The research was conducted using a survey questionnaire in Međimurje County, one of the most developed micro-regions in Croatia, where public administration is partially digitized, making it an excellent case for studying the relevant processes of interest. The sample included 351 respondents from Međimurje County, categorized by gender, age, and level of education. The results showed a significant connection between the importance of the dimensions of maturity, orientation, and quality of e-government and the level of e-participation (measured by the use of the dimensions of maturity and orientation of e-government). Additionally, there was a significant difference in the assessment of the importance of the maturity, orientation, and quality of e-government, in the level of use of dimensions of maturity and orientation of e government, and in the level of e-participation through social networks with regard to gender, age, level of education, and complexity of occupation
Technologies of precise dairy cattle breeding to early prediction of some metabolic disorders
No full textOvo istraživanje imalo je za cilj razviti model za ranu detekciju metaboličkih poremećaja (acidoze i ketoze) kod Holstein krava i procijeniti kako on može smanjiti gubitke u proizvodnji mlijeka te poboljšati održivost farmi. Istraživanje je obuhvatilo analizu dnevnih proizvodnih svojstava, biokemijskih pokazatelja i hematoloških parametara za procjenu metaboličkog statusa, kao i određivanje prevalencije metaboličkih poremećaja kod hrvatskih Holstein krava. Podaci iz baze kontrole mliječnosti (3.856.453 zapisa) korišteni su za istraživanje veze između komponenti mlijeka i metaboličkih poremećaja. Rezultati su pokazali da su krave u riziku od acidoze imale povišene razine AST, GGT, PRO, Fe i Ca, dok je ketoza bila povezana s višim razinama GUK, PRO, TGC i Ca. Prevalencija metaboličkih poremećaja bila je 44,56%, pri čemu je 31,15% krava bilo u riziku od acidoze, a 13,42% od ketoze. Sezonski i faktori veličine farmi utjecali su na pojavu ovih poremećaja. Istraživanje je također pokazalo da metabolički poremećaji negativno utječu na proizvodnju mlijeka, osobito kod krava s ketoza, dok su krave s acidozom pokazale smanjenje proizvodnje mlijeka u ranoj laktaciji. Istraživanje je istaknulo da rana detekcija i prevencija mogu značajno smanjiti ekonomske gubitke, poboljšati zdravlje stada i povećati održivost farmi, doprinosući smanjenju negativnih utjecaja na okoliš poput emisije amonijaka.This research aimed to develop a model for the early detection of metabolic disorders (acidosis and ketosis) in Holstein cows and assess how it can reduce milk production losses and improve farm sustainability. The study involved analyzing daily production traits, biochemical indicators, and hematological parameters to assess metabolic status, as well as determining the prevalence of metabolic disorders in Croatian Holstein cows. Milk recording data (3,856,453 records) were used to explore the relationship between milk components and metabolic disorders. Results showed that cows at risk of acidosis had elevated levels of AST, GGT, PRO, Fe, and Ca, while ketosis was linked to higher GUK, PRO, TGC, and Ca levels. The prevalence of metabolic disorders was found to be 44.56%, with 31.15% of cows at risk for acidosis and 13.42% for ketosis. Seasonal and farm size factors influenced the occurrence of these disorders. The study also demonstrated that metabolic disorders negatively impacted milk yield, especially in cows with ketosis, while cows with acidosis showed reduced milk production in early lactation. The research highlighted that early detection and prevention could significantly reduce economic losses, improve herd health, and enhance farm sustainability, contributing to a decrease in environmental impacts such as ammonia emissions
APPLICATION OF MATHEMATICAL MODELLING IN THE ASSESSMENT OF SORPTION AND DESORPTION CAPACITY OF NEONICOTINOID INSECTICIDES IN AGRYCULTURAL SOILS Doctoral thesis
No full textCiljevi istraživanja: U Slavoniji se neonikotinoidi koriste kao učinkovita sredstva za zaštitu nasada
šećerne repe. Njihovo ponašanje u tlu ovisi o karakteristikama tla, ali i o kemijskoj strukturi molekule.
Cilj ovog istraživanja bio je ispitati utjecaj raznolikosti karakteristika tala i kemijske strukture
neonikotinoida na intenzitet njihova vezivanja na koloide tla. Također, istražiti mogu li procesi sorpcije
i desorpcije, te u kojoj mjeri, kontrolirati dostupnost insekticida i druge procese koji određuju njihovu
sudbinu u okolišu tla. Metode: Uzorci tla prikupljeni su iz dvije hrvatske županije: Požeško-slavonske
i Sisačko-moslavačke i okarakterizirani teksturno i fizikalno-kemijski. Kinetički i ravnotežni
eksperimenti sorpcije i desorpcije acetamiprida, tiakloprida i imidakloprida provedeni su standardnom
„šaržnom“ metodom, dok su njihovi ostatci analizirani pomoću HPLC-MS/MS. Za objašnjenje kinetike
sorpcije i desorpcije korišteni su modeli: pseudo-prvog reda, Elovich-ev, unutar-čestične difuzije i
bifazni model kinetike prvoga reda (TSM). Za ravnotežne procese korišteni su Freundlich-ov,
Langmuir-ov i Temkin-ov model. Rezultati: Iako su analizirani neonikotinoidi slični u veličini i
kemijskoj strukturi, rezultati su pokazali značajne razlike u kinetičkom i ravnotežnom ponašanju procesa
sorpcije/desorpcije. TSM i Freundlich-ov model su se pokazali najprimjerenijima za objašnjenje tih
procesa. Tiakloprid je pokazao bržu sorpciju u usporedbi s acetamipridom i imidaklopridom, a u svim
tlima bio je jače sorbiran u ravnoteži. Unutarčestična difuzija bila je relevantan proces sorpcije
acetamiprida i imidakloprida, ali ne i za tiakloprid. Acetamiprid je lakše desorbiran od preostala dva
neonikotinoida. Acetamiprid i imidakloprid mogu se kategorizirati kao srednje pokretni insekticidi s
manjom tendencijom sorpcije, što povećava vjerojatnost kontaminacije podzemnih voda, dok je
tiakloprid slabo pokretan. Sadržaj organske tvari (OC), kao i njena priroda i struktura, imali su ključnu
ulogu u sorpciji/desorpciji neonikotinoida. Aromatičnost je pogodovala sorpciji, dok je veća
koncentracija hidrofilnih karboksilnih skupina potisnula sorpciju. Imidakloprid je podjednako ispunio
sorpcijska mjesta u gumastoj i staklastoj fazi OC bez obzira na koncentraciju. Sorpcija tiakloprida pri
niskim koncentracijama i acetamiprida pri visokim koncentracijama bila je kontrolirana hidrofilnim
aromatskim strukturama, koje djeluju kao "hvatači" insekticida unutar pora staklaste faze OC. Razlike
u ponašanju sorpcije/desorpcije proizlaze i iz varijacija u molekularnoj strukturi; tiazolidinski prsten
koji sadrži sumpor u tiaklopridu uzrokuje razlike u topljivosti u vodi, lipofilnosti i kiselo-baznim
svojstvima, a time i u interakcijama sa sastojcima tla. Preko atoma N u piridinskom prstenu,
neonikotinoidi mogu stvarati π–π ili p–π interakcije donor-akceptor elektrona s aromatskim dijelovima
organske tvari. Također, heteroatomi N, S i Cl mogu djelovati kao akceptori vodikovih (H–) veza i
stvarati H–veze s funkcionalnim skupinama koje doniraju H u tlu. Zaključak: Matematički modeli
pokazali su se kao učinkoviti alati za predviđanje pokretnosti neonikotinoida u tlu, pomažući u
razjašnjenju mehanizama sorpcije/desorpcije i predviđanju njihove toksičnosti za ljudsku populaciju.
Rezultati istraživanja doprinijet će razvoju budućih strategija sanacije i pomoći u tumačenju mogućih
uzroka kontaminacije usjeva i ekosustava tla, čak i u slučajevima zabrane uporabe neonikotinoida.Objectives: In Slavonia, neonicotinoids are used as effective means to protect of sugar beet planatations.
Their behavior in the soil depends on the soil characteristics and the chemical structure of the molecules.
This research aimed to examine how variability in soil characteristics and the chemical structure of
neonicotinoids affects their binding to soil colloids, and whether sorption and desorption processes
influence the availability of these insecticides and other processes determining their fate in the soil
environment. Methods: Soil samples were collected from Požega-Slavonia and Sisak-Moslavina
counties, and characterized texturally and physico-chemically. Kinetic and equilibrium sorption and
desorption experiments of acetamiprid, thiacloprid, and imidacloprid were carried out using the standard
"batch" method, while their residues were analyzed using HPLC-MS/MS. Models used for kinetics
analysis included pseudo-first order, Elovich’s, intra-particle diffusion, and first-order biphasic model
(TSM), as well as Freundlich, Langmuir, and Temkin models for equilibrium processes. Results:
Despite their similar size and chemical structure, the neonicotinoids exhibited differences in
sorption/desorption behavior. The TSM and Freundlich models proved to be the most suitable for
explaining these processes. Thiacloprid exhibited faster sorption compared to acetamiprid and
imidacloprid, and in all soils it was more strongly sorbed at equilibrium. Intraparticle diffusion was a
relevant sorption process for acetamiprid and imidacloprid, but not for thiacloprid. Acetamiprid was
more easily desorbed, classifying it and imidacloprid as moderately mobile insecticides with a lower
sorption tendency, which increases the likelihood of groundwater contamination, while thiacloprid was
poorly mobile. Organic carbon content (OC) and its structure had a crucial role in the sorption/desorption
of neonicotinoids. Aromaticity favored sorption, while a higher concentration of hydrophilic carboxyl
groups suppressed sorption. Imidacloprid uniformly occupied sorption sites in both the rubbery and
glassy phases of OC, regardless of concentration. The sorption of thiacloprid at low concentrations and
acetamiprid at high concentrations was controlled by hydrophilic aromatic structures, which acted as
"traps" for the insecticides within the pores of the glassy phase of OC. Differences in sorption/desorption
behavior also results from variations in molecular structure; the sulfur-containing thiazolidine ring in
thiacloprid causes differences in water solubility, lipophilicity, and acid-base properties, and thus in the
interactions with soil constituents. Through the N atom in the pyridine ring, neonicotinoids can form π
π or p–π electron donor-acceptor interactions with aromatic parts of organic matter. Additionally,
heteroatoms N, S, and Cl can act as hydrogen (H–) bond acceptors, and form H–bonds with H-donating
functional groups in the soil. Conclusion: Mathematical models have proven to be useful tools for
predicting the mobility of neonicotinoids in soil, helping to elucidate sorption/desorption mechanisms
and predict their toxicity to the human population. The findings of this research will contribute to the
development of future remediation strategies and help in the interpretation of possible causes of crops
and soil ecosystem contamination, even in cases of banning the use of neonicotinoids
EFFECTS OF MULTIPLE ENVIRONMENTAL STRESSORS ON METABOLIC RESPONSES OF FRESHWATER ORGANISMS
No full textAntropogeni pritisci značajno utječu na biološku raznolikost i prirodne resurse. Istraživanje je ispitivalo pojedinačne i kombinirane učinke višestrukih stresora (onečišćujuće tvari/otpadne vode i povišena temperatura vode) na slatkovodne zajednice kroz mikrokozmos (tulari i mahovina) i mezokozmos (slatkovodni beskraljšnjaci i mahovina) eksperiment. Koristeći non-target analizu metabolita i lipida te DNA barkodiranje, proučavane su promjene u fiziološkim, metaboličkim i genetskim odgovorima ne-modelnih organizama na odabrane stresore. Odgovori su se razlikovali ovisno o promatranom svojstvu, vrsti, spolu te životnom stadiju. Molekularni indikatori (tj. metabolom, lipidom, filogenetska raznolikost) su pokazali brže odgovore na stresore nego tradicionalni pokazatelji zdravlja ekosustava (tj. tjelesna težina, preživljavanje, sastav zajednice). Metoda DNA barkodiranja otkrila je suptilne genetičke varijacije potaknute stresorima kod pojedinih vrsta. Negativni učinci povišene temperature na rast i razvoj vodenih kukaca pojačani su prisutnošću onečišćujućih tvari, što upućuje na moguće negativne posljedice za prijenos hranjivih tvari i energije iz vodenih u kopnene ekosustave.Anthropogenic impacts are leaving a mark on biodiversity and natural resources. This research investigated the single and combined effects of several stressors (emerging contaminants/wastewater and increased water temperature) on freshwater biota in a microcosm (caddisflies and moss) and a mesocosm (benthic invertebrates and moss) experiment. Using non-targeted metabolomics and lipidomics, as well as DNA barcoding, the study investigated changes in physiological, metabolic, and genetic responses of non-model freshwater organisms to selected stressors. The responses to stressors were trait-, species-, sex- and life stage-specific. Molecular indicators (i.e. metabolome, lipidome, phylogenetic diversity) responded faster to stressors then ecosystem health indicators (i.e. body mass, survival, community composition). The DNA barcoding method revealed subtle and species-dependent genetic variations triggered by stressors. Negative effects of increased temperature on development-related traits of aquatic insects appear to be intensified by the presence of contaminants in water, suggesting potential negative effects for aquatic-terrestrial subsidies
Model identiteta u kontekstu – socioekonomske nejednakosti u obrazovnim i karijernim ishodima
No full textThis study aimed to assess the social class gap in various educational and vocational outcomes among middle school students in Croatia by testing the newly established Identities in context model. The model posits that lower-class students are more prone to experiencing various threats to their social class identity – psychological barriers – in their educational surroundings, which should explain part of the social class gap in various educational and vocational outcomes. The model also highlights the role of the wider social context in determining the levels of perceived psychological barriers among lower-class students, thereby influencing their outcomes. A total of 1012 6th-year and 7th-year students participated in this two-wave study. Students completed an online questionnaire comprising various socioeconomic indicators and measures of psychological barriers, contextual variables, and educational and vocational outcomes. Results partially confirmed the mediating role of psychological barriers in the relationship between students’ SES and educational and vocational outcomes. Stereotype vulnerability was the most consistent mediator of this relationship, followed by the incompatibility between students’ social class identity and the stereotype of a typical university student. In contrast, the mismatch between students’ social class identity and being a successful pupil was not an important psychological barrier among lower-class students in this sample. Additionally, the results confirmed the detrimental role of competence stereotypes in heightening the perception of different psychological barriers among lower-class students. In contrast, the role of other measured contextual variables was found to be inconsistent or in opposition to the model’s hypotheses. This study highlights the importance of studying the social class education and vocation gap comprehensively to help the design and implementation of interventions aimed at reducing the perception of identity threat among the most vulnerable groups of students.S obzirom na rastuću važnost obrazovanja u današnjem svijetu, kao i njegove uloge u predviđanju različitih individualnih i društvenih ishoda, ključno je pravovremeno prepoznati učenike koji su u riziku od akademskog neuspjeha. Brojna istraživanja pokazuju da učenici iz obitelji nižeg socioekonomskog statusa (SES-a) postižu lošiji školski uspjeh, pokazuju manje adaptivnih motivacijskih obrazaca te izražavaju niže obrazovne aspiracije. Ove se razlike između učenika iz obitelji višeg i nižeg SES-a najčešće objašnjavaju različitim strukturalnim čimbenicima ili pak individualnim razlikama u sposobnostima i uloženom trudu u obrazovanje. Ipak, novija istraživanja se sve češće usmjeravaju na značaj društvenog identiteta u stvaranju i održavanju razlika u obrazovnim i karijernim ishodima zmeđu ove dvije skupine učenika. Konkretno, pretpostavlja se da su učenici svjesni postojećih obrazovnih i karijernih razlika između učenika koji dolaze iz obitelji različitog SES-a, što utječe na njihov vlastiti doživljaj sebe kao pripadnika pojedine društvene klase unutar obrazovnog konteksta. Jedan od modela iz područja socijalne psihologije koji se usmjerava na važnost značenja koje pojedinci iz obitelji različitog SES-a pridaju vlastitoj društvenoj klasi je Model identiteta u kontekstu.
Model identiteta u kontekstu pretpostavlja da će učenici nižeg SES-a, dijelom zbog načina na koji percipiraju svoj klasni identitet, češće doživljavati različite psihološke barijere unutar obrazovnog konteksta. Na primjer, ti će učenici češće percipirati okolinske prijetnje usmjerene prema njihovom klasnom identitetu te će u većoj mjeri osjećati nekompatibilnost između njihovog klasnog identiteta i uspjeha u obrazovanju. Model zatim pretpostavlja da će spomenute psihološke barijere posredovati povezanost između SES-a učenika i njihovih obrazovnih i karijernih ishoda, time objašnjavajući dio razlika između učenika iz obitelji različitog SES-a. Dodatno, model pretpostavlja i postojanje različitih kontekstualnih čimbenika koji utječu na pojavnost i izraženost psiholoških barijera kod učenika niskog SES-a. Konkretno, u modelu se ističu tri grupe kontekstualnih čimbenika koji bi, ukoliko su prisutni u pojedinom kontekstu, trebali ojačati vezu između SES-a učenika i razine doživljenih psiholoških barijera. Prva skupina okolinskih čimbenika se odnosi na negativna očekivanja okoline od učenika iz obitelji nižeg SES-a, poput stereotipa o sposobnostima tih učenika. Druga skupina se odnosi na nedostatak pozitivne reprezentacije osoba iz obitelji nižeg SES-a u obrazovanju ili u profesijama koje zahtjevaju višu razinu obrazovanja. Posljednja, treća skupina kontekstualnih čimbenika se odnosi na negativnu orijentaciju osoba nižeg SES-a prema obrazovanju. Unutar treće skupine se ističe uloga roditelja u prenošenju vrijednosti obrazovanja na svoju djecu, putem akademske socijalizacije ili obrazovnih očekivanja.
Glavni cilj ovog istraživanja je bio ispitati temeljne postavke Modela identiteta u kontekstu na populaciji učenika završih razreda osnovnih škola u Hrvatskoj. Planirano je ispitati razlike u pojedinim obrazovnim i karijernim ishodima između učenika koji se razlikuju po obiteljskom SES-u te provjeriti može li se dio tih razlika pripisati razlikama u doživljaju psiholoških barijera unutar obrazovnog konteksta. Dodatno je ispitana moderacijska uloga tri kontekstualna čimbenika u povezanosti između SES-a učenika i psiholoških barijera, kao i njihova moderacijska uloga u cijelom medijacijskom putu od SES-a učenika na njihove obrazovne i karijerne ishode posredstvom psiholoških barijera.
Ovo istraživanje je dio šireg projekta Hrvatske zaklade za znanost FreeCareerChoice. U okviru ovog istraživanja se pratilo 420 učenika šestih razreda (Mdob = 12.59, SDdob= 0.52) i 439 učenika sedmih razreda (Mdob = 13.61, SDdob = 0.55) kroz dva vala istraživanja odvojenih jednogodišnjim periodom. Učenici su u dva navrata rješavali online upitnik za vrijeme redovne nastave u kojem su dali podatke o SES-u njihove obitelji, percepciji psiholoških barijera, određenim kontekstualnim čimbenicima te odabranim obrazovnim i karijernim ishodima.
Rezultati su djelomično potvrdili pojedine dijelove Modela identiteta u kontekstu. Pokazalo se da učenici nižeg SES-a uistinu doživljavaju više psiholoških barijera od njihovih vršnjaka iz obitelji višeg SES-a, što djelomično može objasniti određene razlike u obrazovnim i karijernim ishodima učenika s obzirom na SES njihove obitelji. Konkretno, učenici nižeg SES-a češće izvještavaju kako ih drugi pojedinci unutar obrazovnog konteksta nepovoljno tretiraju zbog SES-a njihove obitelji, odnosno o osjećaju prijetnje zbog njihovog klasnog identiteta, što dovodi do niza negativnih posljedica po njihovo obrazovanje i buduću karijeru. Nadalje, učenici nižeg SES-a također percipiraju da je njihov klasni identitet u manjoj mjeri kompatibilan s identitetom osobe koja studira, kao i s prototipom uspješnog učenika, što dovodi do lošijeg školskog uspjeha, manje adaptivnih motivacijskih obrazaca te do nižih obrazovnih aspiracija. Pritom treba naglasiti da su samo neki od medijacijskih puteva bili statističko značajni, ovisno o korištenim indikatorima SES-a, psiholoških barijera te obrazovnih i karijernih ishoda, što naglašava važnost sveobuhvatnog mjerenja složenih koncepata, poput SES-a ili psiholoških barijera, prilikom istraživanja obrazovnih nejednakosti.
Nadalje, rezultati također potvrđuju moderacijski učinak svjesnosti o stereotipima na povezanost između SES-a učenika i doživljaja psiholoških barijera. Konkretno, učenici koji percipiraju da su njihove obitelji nižeg SES-a od prosječne hrvatske obitelji su doživljavali više psiholoških barijera kad su bili svjesniji postojanja stereotipa o sposobnosti siromašnih ljudi u njihovom okruženju. Pojačana percepcija psiholoških barijera je nadalje negativno predviđala različite obrazovne i karijerne ishode kod ove skupine učenika. S druge strane, moderacijski učinak ostalih mjerenih kontekstualnih čimenika nije bio konzistentan ili nije bio u skladu s očekivanjima Modela identiteta u kontekstu. Na primjer, postojanje uzora u obrazovanju je samo u malom broju slučajeva dovodilo do promjene u povezanosti SES-a učenika i doživljaja psiholoških barijera, dok su roditeljske aspiracije djelovale u drugačijem smjeru od teorijskih očekivanja. Konkretno, pokazalo se da učenici iz obitelji višeg SES-a doživljavaju veći broj psiholoških barijera kada su aspiracije njihovih roditelja niske, što pak dovodi o manje adaptivnih motivacijskih obrazaca kod ove skupine učenika.
Općenito, rezultati istraživanja upućuju na zaključak da su učenici nižeg SES-a u većem riziku od postizanja neadekvatnih obrazovnih razultata u završnim razredima osnovnih škola u Hrvatskoj dijelom zbog povišene percepcije različitih psiholoških barijera u obrazovnom kontekstu. Od kontekstualnih karakteristika koje pojačavaju doživljaj psiholoških barijera kod ovih učenika se istaknula svjesnost o stereotipima o sposobnostima siromašnih osoba, gdje učenici nižeg subjektivnog SES-a percipiraju više razine ovih barijera kada su svjesniji postojanja štetnih stereotipa u njihovoj okolini. Rezultate istraživanja valja interpretirati oprezno s obzirom na ograničenja u metodologiji istraživanja i statističkom pristupu u obradi podataka. Buduća bi istraživanja trebala obuhvatiti više točaka mjerenja, kako bi se omogućila bolja kontrola rezultata iz prijašnjih točaka mjerenja i robusniji zaključci oko uzročno-posljedičnih odnosa u modelu. Također, potrebno je adaptirati pojedine instrumente korištene u ovom istraživanju kako bi bili prilagođeniji osnovnoškolskoj populaciji i povijesnom, društvenom i političkom kontekstu u kojem se istraživanje provodi.
Usprkos ograničenjima, ovo istraživanje ima niz važnih teorijskih i praktičnih doprinosa. Za početak, ovo je prvo istraživanje koje sveobuhvatno testira Model identiteta u kontekstu, potvrđujući neke od temeljnih postavki modela. Dodatno, ovo je jedno od rijetkih istraživanja koje ispituje procese povezane s klasnim identitetom u kontekstu obrazovnih nejednakosti na osnovnoškolskom uzorku, s obzirom na to da su se dosadašnja istraživanja u većini slučajeva usmjerila na ispitivanje ovih procesa na višim razinama obrazovanja. Osim što je provedeno na manje istraženoj populaciji po starosnoj dobi, teorijski doprinos istraživanja je i činjenica da je većina ovakvih istraživanja provedena u zapadnim dijelovima svijeta, koji se u mnogočemu razlikuju od hrvatskog obrazovnog kao i društveno-povijesnog konteksta. Od praktičnih doprinosa istraživanja je važno naglasiti potencijal koji rezultati istraživanja imaju u osmišljavanju i implementaciji raznih socio-psiholoških intervencija u obrazovnom kontekstu. Konkretno, rezultati upućuju da smanjivanje stereotipa o sposobnostima siromašnih ljudi može pozitivno utjecati na smanjenje psiholoških barijera kod učenika koji percipiraju da je njihova obitelj niskog SES-a. Smanjenjem psiholoških barijera kod ove skupine učenika moguće je pozitivno djelovati na njihov školski uspjeh, motivaciju i obrazovne aspiracije, time smanjujući jaz u obrazovnim ishodima između učenika iz obitelji različitog SES-a
Modeliranje procesa deformiranja hiperelastičnih materijala pomoću fizikalno proširenih neuronskih mreža : doktorski rad
No full textMachine learning has gained an important place both in daily interactions and in scientific
development. It has a wide range of applications and many different approaches which can
be used to solve various problems. Neural networks are one of these approaches and are
a potent regression tool which is applied in a large number of scientific fields. In recent
years it has gained popularity in the field of computational mechanics as an alternative
material model replacing (or complementing) existing analytical models. These neural
network models are useful for describing complex relationships that existing models can
not fully describe. They are also used as a general model that can be applied to a wide
range of materials. This thesis places a focus on the latter, with the aim of creating a
general material model for hyperelastic materials such as rubber. With analytical models
there is a need to fit different models (Neo-Hookean, Mooney-Rivlin, Ogden, Yeoh, Gent,
etc.) to experimental data and use the one that approximates the data best. Each analytical model has some advantages compared to the others as well as drawbacks, and the
choice of the model also depends on what the application of the model will be. By using
a neural network as a model the goal is to obtain a single model that has no drawbacks
and can function for any material. This also speeds up the material modelling process as
only one single model is generated instead of fitting multiple models and choosing between them. In this thesis a detailed investigation is made between different modelling
strategies. Firstly, a neural network that predicts stress from strain is developed and is a
representative of the most common approach in neural network modelling. Afterwards, a
more general model using the same neural network architecture is created that is similar
to conventional invariant models so that it predicts the energy while taking the invariants
of the right Cauchy-Green deformation tensor as inputs. It was demonstrated that it can be
used as a direct replacement for the invariant models by reusing the existing framework
for the numerical implementation of invariant based models. Secondly, a significant improvement to the neural network architecture is done through the implementation of a
custom activation function suited for modelling of hyperelastic behaviour. It is accompanied by the implementation of certain conditions from solid mechanics such as objectivity,
thermodynamic consistency, normalisation of energy, non-negativity of energy, normalisation of stress and polyconvexity. All of these improvements have created a neural
network model, referred to as LINEXP-PANN, that can capture a wider range of material behaviours with a significantly reduced dataset size compared to the previous simpler
neural network models. The LINEXP-PANN model was used for modelling damage in
rubber-like materials which is known as the Mullins effect. A new modelling strategy was
developed for modelling the Mullins effect using neural networks where certain weights
are reused and shared within the neural network. The majority of the work is based on
the assumption of incompressibility, a common assumption when modelling rubber-like
materials. The LINEXP-PANN model was also extended to compressible behaviour confirming the general modelling capabilities of the model. Finally, a comparison is made
between the LINEXP-PANN model and another data-driven method called Data-Driven
Computational Mechanics (DDCM) where the advantages of the LINEXP-PANN model
are demonstrated.Strojno učenje je postalo dio naše svakodnevice i dio znanstvenoga razvoja. Ima široko
područje primjene i postoje mnogi različiti pristupi koje se može primijeniti za rješavanje
problema. Neuronske mreže su jedan od tih pristupa i moćni su regresijski alat koji se
primjenjuje u mnoštvu znanstvenih polja. Sa porastom primjene strojnog učenja u inženjerstvu, neuronske mreže postaju sve popularniji alternativni materijalni model koji
zamjenjuje (ili nadopunja) postojeće analitičke modele. Materijalni modeli temeljeni na
neuronskim mrežama su korisni za opisivanje složenih ponašanja koje postojeći analitički
modeli ne mogu u potpunosti opisati. Također se koriste i kao opći modeli koji mogu
opisati širi raspon materijala. U ovom doktorskome radu se pozornost stavlja na drugo
svojstvo primjene gdje se želi stvoriti opći materijalni model za hiperelastične materijale sa naglaskom na materijale slične gume. Kada se koriste analitički modeli potrebno
je prilagoditi više modela (Neo-Hookean, Mooney-Rivlin, Ogden, Yeoh, Gent, itd.) na
eksperimentalne podatke i odabrati onaj model koji najbolje opisuje podatke. Svaki analitički model ima neke prednosti u odnosu a druge modele, no i nedostatke u odnosu na njih,
te se mora odabrati model ovisno o tome koji najviše odgovara određenoj primjeni. Koristeći neuronsku mrežu kao model cilj je dobiti jedinstveni model koji nema nedostataka i
može se koristiti za bilo koji materijal. Ovo također ubrzava proces materijalnoga modeliranja jer je potrebno prilagoditi samo jedan model umjesto više njih između kojih se mora
birati. Prvi korak u radu je bio razvoj neuronske mreže koja predviđa naprezanje iz deformacije i predstavnik je uobičajenoga načina modeliranja neuronskim mrežama. Potom
je stvoren općenitiji model temeljen na istoj arhitekturi neuronske mreže koji je sličan invarijantnim modelima jer predviđa energiju i koristi invarijante desnog Cauchy-Greenova
tenzora deformiranja kao ulazne podatke. Pokazalo se da ovaj model može biti korišten i
kao jednostavna zamjena za klasične invarijantne modele jer koristi već postojeće rutine za
računarsku implementaciju invarijantnih modela. Drugi korak čine unaprijeđenja samoj
arhitekturi neuronske mreže od kojih je najznačajnija implementacija vlastite aktivacijske
funkcije primjerene modeliranju hiperelastičnoga ponašanja. Korištenje vlastite aktivacijske funkcije omogućava ispunjenje određenih uvjeta iz mehanike čvrstoga tijela poput
objektivnosti, termodinamičke konzistencije, normalizacije energije, ne-negativnost energije, normalizacija naprezanja i polikonveksnost. Promjene u arhitekturi i ispunjenje
ovih uvjeta su vodile stvaranju modela temeljenog na neuronskoj mreži kojem se nadjenulo ime LINEXP-PANN (Linear EXPonential Physics-Augmented Neural Network,
hrv. linearno eksponencijalna fizikalno proširena neuronska mreža). Ovaj model može
opisati široki raspon materijalnih ponašanja koristeći znatno manju količinu podataka za
treniranje neuronske mreže u usporedbi sa jednostavnijim modelima predstavljenim u prvome koraku. Prethodno spomenuti LINEXP-PANN model je korišten i za u modeliranju oštećenja kod gumenih materijala koji je poznat kao Mullinsov efekt. Razvijen je
novi pristup modeliranju Mullinsova efekta neuronskim mrežama koji je specifičan jer su
određene težine dijeljene u neuronskoj mreži među njenim dijelovima. Većina ovoga rada
je temeljena na pretpostavci nestlačivosti koja je česta u kontekstu modeliranja gumenih
materijala. Novorazvijeni LINEXP-PANN model je proširen i za modeliranje stlačivog
hiperelastičnog ponašanja čime se dodatno potvrđuju prilagodljivost i općenitost modela.
Naposljetku je napravljena usporedba između LINEXP-PANN modela i jedne alternative
metode temeljene na podacima Data-Driven Computational Mechanics (DDCM, hrv. podacima pogonjena računalna mehanika) te su prikazane prednosti LINEXP-PANN modela
Ethanol production potential of non-declared maize hybrids grown at different plant densities
No full textKukuruz se globalno najviše koristi kao stočna hrana, ali je važan i kao prehrambeni usjev. Osim toga, kukuruz se sve više koristi za proizvodnju etilnog alkohola koji se nakon miješanja s benzinskim gorivima koristi kao pogonsko gorivo, te pri tome pridonosi zadovoljavanju kriterija smanjivanja emisije ugljičnog dioksida u atmosferu. U svijetu vodeću ulogu u proizvodnji i primjeni etanola kao pogonskog goriva imaju SAD i Brazil. Najveći proizvodni kapaciteti u Europskoj uniji nalaze se u Francuskoj, Njemačkoj i Mađarskoj. Ovakva djelatnost, stvaranjem dodatne vrijednosti doprinijela bi gospodarskom i industrijskom razvoju Republike Hrvatske. Iako se u prošlosti dosta govorilo o pokretanju „greenfield“ investicije, izgradnje postrojenja za preradu kukuruza u etanol u Republici Hrvatskoj, do toga još nije došlo. Kada se govori o proizvodnji sjemena hibrida kukuruza može se utvrditi da kod nas postoji jaka oplemenjivačka djelatnost, međutim, do sada u Hrvatskoj nije postojao ciljani oplemenjivački program selekcije kukuruza za namjensku proizvodnju etanola.
Cilj istraživanja bio je utvrditi razliku u proizvodnji zrna i etanola iz kukuruza između domaćih, nenamjenskih hibrida kukuruza koji se uobičajeno koriste za proizvodnju zrna i uvezenih HTF (High Total Fermentable) hibrida namjenjenih za proizvodnju etanola.
Poljski pokus je postavljen na 3 lokacije (Kneževo, Osijek, i Šašinovec), dvije godine uzastopno (2012, 2013), u tri gustoće sklopa (60.000, 70.000 i 80.000 biljaka/ha). Hibridi tvrtke Pioneer, deklarirani kao “HTF” hibridi za proizvodnju etanola iz zrna kukuruza korišteni su kao kontrola za procjenu produktivnosti etanola iz domaćih hibrida Poljoprivrednog instituta Osijek i Bc Instituta d.d. Laboratorijska proizvodnja etanola utvrđena je Lemuz metodom.
Zbog kompleksnog dizajna pokusa i načina na koji su prikupljeni podaci statistička analiza je provedena prema različitim modelima za različita svojstva. Za prinos zrna analiza je provedena u dvije faze. U prvoj fazi analizirani su objedinjeni podaci iz svih pokusa prema kompleksnom hijerarhijskom modelu koji je odgovarao dizajnu pokusa, a koji je uključivao efekte godina, lokacija, gustoće sklopa, hibrida, sve njihove interakcije, te tri različite pogreške. Za sve ostale varijable (sadržaj škroba, hektolitarska masa, omjer amiloze i amilopektina, te sadržaj etanola) podaci su prikupljeni na temelju jednog uzorka za svaku kombinaciju gustoće sklopa i hibrida u svakom pokusu, pa je model prema kojem su podaci analizirani uključivao efekte godina, lokacija, gustoća sklopa i hibrida, te sve njihove interakcije, osim četverostruke interakcije (godina x lokacija x gustoća sklopa x hibrid) koja se nije mogla razdvojiti od pogreške.
Promatrajući dobivene rezultate analiziranih svojstava u 2013. godini ostvaren je viši prosječni prinos zrna po jedinici površine u iznosu od 7,31 dt, te je prosječni sadržaj škroba bio veći za 0,4 % čemu su doprinijeli bolji vremenski uvjeti u navedenoj sezoni. Preostala svojstva u 2013. godini bilježe manje rezultate u odnosu na 2012. godinu i to: hektolitarska masa zrna za 0,9 kg, omjer amiloze i amilopektina za 0,009, a prinos etanola za 6,63 l/t.
Hibridi koji su namijenjeni za proizvodnju etanola ostvarili su veći prinos zrna i veći prinos etanola. Najveći prinos zrna ostvario je HTF hibrid (PR37Y12). Međutim neznatno manji prinos ostvario je hibrid Os 378 iz domaće selekcije. Najveći pojedinačni prinos etanola po toni zrna ostvario je hibrid Bc 532, nenamjenski hibrid domaće selekcije, a neznatno manje etanola po toni zrna dao je HTF hibrid PR35F38. HTF hibridi zbog većeg prinosa zrna po hektaru i zbog boljeg prinosa etanola iz jedne tone zrna ostvaruju ukupno veće prinose etanola po jedinici površine. Svi hibridi nisu ostvarili najveće prinose zrna i etanola u gušćem sklopu, kako je bilo za očekivati. Iz ovog istraživanja nameće se zaključak da se na lokacijama na kojima su provedena istraživanja i u klimatskim uvjetima koji su vladali tijekom 2012. i 2013. godine gustoća sklopa od 70.000 biljaka/ha pokazala kao najbolja u proizvodnji etanola po jedinici površine.Meeting the criteria for reducing the emission of carbon dioxide into the atmosphere is an important factor in reducing the impact of climate change on today's life. Given that the Republic of Croatia annually generates a certain surplus in the production of corn grains, that could potentially be used in ethanol processing. The goal of the research was to determine the difference in the production of grain and ethanol from corn between domestic, non-purpose corn hybrids that are commonly used for grain production and imported HTF (High Total Fermentable) hybrids intended for ethanol production. Corn is globally used primarily as animal feed, but it is also important as a food crop. In addition, corn is increasingly used for the production of ethyl alcohol, which, after mixing with gasoline, is used as a motor fuel. Production technologies vary and can generally be divided into three stages: pre-treatment, fermentation and ethanol extraction. In the world, the leading role in the production and use of ethanol as a fuel is played by the USA and Brazil. The largest production capacities in the European Union are located in France, Germany and Hungary. By creating additional value, this kind of activity would contribute to the economic and industrial development of the Republic of Croatia. Although in the past there was a lot of talk about starting a "greenfield" investment, the construction of a plant for processing corn into ethanol in the Republic of Croatia has not yet happened. When talking about the production of corn hybrid seeds, it can be established that there is a strong breeding activity in Croatia, however, until now, there has been no targeted breeding program for the selection of corn for the purposeful production of ethanol.
Materials and methods: A total of six maize hybrids that belong to the FAO groups 300 and 500 were sown. These hybrids are: Bc 344 and Bc 532 from the breeding program of Bc Institut za oplemenjivanje i selekciju bilja d.d., Os 378 and Ossk 515 from the breeding program of Poljoprivredni Institut Osijek and PR37Y12 and PR35F38 belonging to Corteva Agriscience Croatia d.o.o. (before Pioneer Sjeme d.o.o.). Hybrids from the breeding program of the Bc Institute and the Agricultural Institute from Osijek were chosen as high-yielding hybrids in their crop groups, and hybrids from Corteva Agriscience Croatia d.o.o. as declared "HTF" hybrids for purposeful corn production for ethanol production. All hybrids were created without the use of biotechnology and are classified as high-yielding corn hybrids. Field experiments were conducted during two growing seasons and at three locations. The selected locations where the research was conducted (Kneževo, Osijek and Šašinovec) differ from each other in pedological and climatic properties. At the Kneževo location, the soil type is carbonate chernozem on loess and represents the best quality soil in the Republic of Croatia. In both growing seasons, the pre-crop to corn was sugar beet. The field experiments at the Osijek location were planted on a semi-gley soil leached on a banner, and the pre-culture in both vegetations was wheat. The type of soil at the Šašinovec location where the field experiments were set up is classified as a fluvisol and is characterized by a powdery clay loamy texture. The pre-crop in both years was spring barley. In the experiments, selected corn hybrids were grown in both years under conditions of intensive production, which included deep plowing, application of a higher level of fertilization, application of herbicides before and after emergence, and inter-row cultivation. An identical two-factorial experiment was set up in four replicates at all locations. The main factor in the experiment is the plant density, and the sub-factor is the hybrid. Field experiments were sown at each location separately, and all members of the experiment at a particular location were sown on the same day (same date). The target plant densities were: 60.000, 70.000 and 80.000 plants/ha. Sowing for each plot was done with 20% more seeds, and then after emergence, in phase 3 developed leaves, manual thinning was done to the given plot. Sowing was done with a four-row Wintersteiger "TC 2700" pneumatic seed planter, and experimental harvesting was done in the physiological ripening stage using a
two-row Wintersteiger "Nurserymaster Elite" combine, which is specialized for microexperiments.
In the Seed Testing Laboratory of the Croatian Centre for Agriculture, Food and Rural Affairs - Institute for Seed and Seedlings (today the Croatian Agency for Agriculture and Food - Centre for Seed and Seedlings), sample preparation was carried out, which included drying in the "NI00CF" drying oven (ELE International, Leighton Buzzard, UK) at 130 °C to constant weight and grinding on a “Cemotec 1090” hammer mill (Foss A/s, Hillerød, Denmark), with sieves of 3 mm diameter. The ground samples, whose average weight was 25 g, were used in the Laboratory for Soil, Plant and Fertilizer Analysis, Faculty of Agrobiotechnical Sciences, Osijek, to determine the ethanol yield. The ground samples were homogenized, and 25 g of the sample was placed in a 125 mL Erlenmeyer flask. 75 ml of distilled water was added to the flasks. The pH of the suspension was adjusted to 6,0-6,5 with a dilute NaOH solution. An aliquot of α-amylase (Termamyl, SC DS, Novozymes, Denmark), 27 μl/flask (108 μl/100 g maize) was added to the suspension with a digital pipette. Flasks with corn suspension and α-amylase were placed in a water bath at 90 °C and kept for 60 min after reaching the desired temperature. To avoid coagulation of the suspension, the flasks were shaken strongly during the first 5 minutes and then every 20 minutes. After 60 min, the flasks were taken out and cooled to 40 °C, and by adding 325 μl of concentrated HCl solution (20 % v/v), the pH of the suspension was adjusted to 4,5-5,0. 4,2 mL of yeast solution (Fleischmann's, Fenton, MO, USA), 400 μL of 12 % (NH4)2SO4, and 20 μL of glucoamylase (Attenuzyme Core, Novozymes, Denmark) were then added to each flask. The flasks were closed with rubber stoppers into which needles (18 ga x 38,1 mm) were inserted. The initial weight of the flask with corn mash, enzymes and yeast was weighed. The flasks were placed in a bath at 150 rpm and 32 °C for 64 hours (Figure 18). After fermentation, the final weight of the flask with corn mash, enzymes and yeast was weighed. A blank (no corn, enzyme, or yeast) was used to check for potential evaporation errors. Evaporation from the blank during fermentation was negligible. Ethanol yield was determined by the gravimetric method (Lemuz et al. 2009) as the difference in weight after fermentation (separated CO2). In working samples on the whole grain, the following were determined: starch content, protein content, oil content, water content and hectoliter mass. The mentioned parameters were determined using the NIR device Infratec Grain Analyzer 1241 (FOSS, Denmark). Also, in the same grain samples, the amylose content was determined using the method developed by the company Megayzime (Wicklow, Ireland). The content of amylopectin was determined mathematically on the basis of the obtained values for amylose.
Due to the complex design of the experiments and the way in which the data were collected, the statistical analysis was performed according to different models for different characteristics. The statistical analysis was carried out in the R environment, where in addition to the basic application, specialized packages were also used: „lme4“, „lmerTest“, „multcomp“ i „emmeans“.
Results and conclusions: In 2013, a higher average grain yield per unit area was achieved in the amount of 7,31 dt, and the average starch content was higher by 0,4 %, which was affected by better weather conditions in the mentioned season. The remaining properties in 2013 recorded lower results compared to 2012: hectoliter grain weight by 0,9 kg, ratio of amylose and amylopectin by 0,009, and ethanol yield by 6,63 l/t. For the most complex interaction: year x location x assemblage x hybrid, a significant (P=0,001) difference in grain yield was determined. In the conducted research, grain yield changed from year to year and from location to location. The differences in the yield between the examined years were mostly affected by the yield at the Kneževo and Osijek locations, where the yields were around 20,04 dt and 12,26 dt lower than the average of all locations for 2012. In 2013, weather conditions were more favorable for corn production, as it is evident from the yield data that the average grain yield at the Kneževo location in 2013 was higher for 35,64 dt. It is interesting to note that the higher yield at the Šašinovec location was determined in 2012, not in 2013. Although the weather was generally more favorable in 2013, there are two facts that must be taken into account, namely that the amount of precipitation is always higher in
the western part of continental Croatia and that in both years the decrease in the amount of precipitation was less in Šašinovac in compared to Kneževo and Osijek. Analysis of variance revealed a statistically significant (P=0,05) difference in the interaction of years, locations and hybrids, and a statistically significant (P=0,01) difference in the interaction of years and systems in ethanol yield. The average yield of ethanol in 2012 was 130 l/t grain. In 2013, although it was more favorable for growing corn, the ethanol yield was lower on average, which was 124 l/t of grain. This is a bit unusual considering that in 2013 higher grain yields were found, and during the growing season no significant stress conditions were found that would affect ethanol production. In other words, this means that there are some other factors that affect the possibility of converting starch into ethanol. On average, the highest amount of ethanol was obtained per ton of grain at the Kneževo location (129 l/t of grain), and the lowest at the Osijek location (123 l/t of grain). At the Šašinovec location, an average of 128 l/t of grain was obtained. Among the hybrids, on average, the highest amount of liters of ethanol per ton of grain was obtained with the hybrid Bc 532 (131 l/t of grain). Only slightly less ethanol per ton of grain was found in hybrid PR35F38 (130 l/t). The analysis of variance revealed a statistically significant (P=0,001) difference in the interaction of year and hybrid, and between hybrids and years in the starch content of grain. A statistically significant (P=0,01) difference was found in the interaction of years and locations. The effect of plant density is also statistically significant (P=0,01) but is not included in any significant interaction. According to the data obtained from this research, the starch content was higher on average in 2013 and was 71,44 % compared to 2012 when it was 70,99 %. In 2013, the climatic conditions were more favorable, which was reflected in a slightly higher starch content in corn kernels. On average, the most starch was determined at the Šašinovec location and was 71,30 %, which was slightly higher than the starch content determined at the Osijek location (71,24 %) and at the Kneževo location (71,10 %). On average, the highest starch content was found in the PR35F38 hybrid and was 71,74 %. Another four hybrids had an average starch content of more than 71,00 %. Analysis of variance revealed a statistically significant (P=0,001) difference in the interaction of year, location, and hybrid in relation to hectoliter grain weight. The average hectoliter mass was higher in 2012 and amounted to 74,56 kg/hl compared to 2013, when the value for the hectoliter mass was 73,56 kg/hl. The highest average hectoliter weight was determined at the Šašinovec location and was 74,68 kg/hl. On the other hand, the smallest hectoliter mass was determined at the Osijek location and was 73,54 kg/hl. In the case of hybrids, on average, the highest hectoliter mass was found in the hybrid PR35F38 (76,56 kg/hl), and the lowest in the hybrid Ossk 515 (72,38 kg/hl). Analysis of variance revealed a statistically significant (P=0,05) difference in the interaction of year and location in the ratio of amylose and amylopectin. In 2012, a slightly higher ratio of amylose and amylopectin was determined and was 0,271, compared to 0,262, which was the same in 2013. In hybrids, the lowest average ratio between amylose and amylopectin was 0,256 in the PR37Y12 hybrid, and the highest in the amount of 0,272 in the Bc 532 hybrid. At the other two locations, it was smaller, 0,264 at the Osijek location and at the Šašinovec location.
Hybrids intended for ethanol production achieved higher grain yield and higher ethanol yield. The highest grain yield was achieved by the HTF hybrid (PR37Y12). However, a slightly lower yield was achieved by the hybrid Os 378 from domestic selection. The highest individual yield of ethanol per ton of grain was achieved by the hybrid Bc 532, a non-purpose hybrid of domestic selection, and slightly less ethanol per ton of grain was produced by the HTF hybrid PR35F38. HTF hybrids, due to higher grain yield per hectare and better ethanol yield from one ton of grain, achieve overall higher ethanol yields per unit area. All hybrids did not achieve the highest yields of grain and ethanol in a denser structure of plant/ha, as it was expected. The conclusion of this research is that in the locations where the research was conducted and in the climatic conditions that prevailed during 2012 and 2013, the sowing density of 70.000 plants/ha proved to be the best in ethanol production per unit area
THE INFLUENCE OF RENAL REPLACEMENT THERAPY ON THYROID FUNCTION IN PATIENTS WITH CHRONIC KIDNEY DISEASE
No full textCilj istraživanja: Odnos između funkcije štitnjače i bubrežne funkcije kod bolesnika s
kroničnom bubrežnom bolešću (KBB) još uvijek nije u potpunosti razjašnjen. Ovo
prospektivno istraživanje provedeno u jednom centru imalo je za cilj ispitati funkciju štitnjače
kod predijaliznih bolesnika u četvrtom i petom stupnju KBB-a, bolesnika koji se liječe
peritonejskom dijalizom (PD), hemodijalizom (HD) te kod primatelja bubrežnog presatka.
Također je praćena smrtnost po skupinama, broj hospitalizacija te mogući utjecaj funkcije
štitnjače na bubrežnu funkciju i kliničke ishode bolesnika. Istraživanje je provedeno na Zavodu
za nefrologiju, dijalizu i transplantaciju bubrega, Klinike za internu medicinu, Kliničkog
bolničkog centra Rijeka.
Ispitanici i metode: Istraživanje je uključilo 108 bolesnika: 24 s KBB-om četvrtog stupnja (G4),
19 s KBB-om petog stupnja koji još nisu bili na dijalizi (G5ND), 18 liječenih PD-om, 24
liječena HD-om i 23 bolesnika kod kojih je učinjena transplantacija bubrega (T). Razdoblje
praćenja trajalo je 24 mjeseca tijekom kojih je funkcija štitnjače ispitivana određivanjem TSH,
T3, fT3, T4, fT4 te protutijela na štitnjaču (antiTPO, antiTg, TSI). Analizirali smo korelaciju
između razina hormona štitnjače i bubrežne funkcije kao i ostatne 24h dnevne diureze te
funkcije bubrežnog presatka u različitim skupinama bolesnika.
Rezultati: Kod bolesnika s KBB-om četvrtog (G4) i petog (G5ND) stupnja razine TSH ostale
su unutar referentnih vrijednosti nakon 24 mjeseca, iako su uočene promjene u razinama T3 i
fT4. Značajna negativna korelacija između fT4 i razina kreatinina uočena je kod bolesnika s
petim (G5ND) stupnjem KBB-a. Kod bolesnika liječenih PD-om, povišene razine TSH
normalizirale su se tijekom vremena praćenja, a razine T4 i fT3 bile su značajno više u
usporedbi s bolesnicima liječenih HD-om. Također, zabilježena je pozitivna povezanost između
razine T4 i 24-satne diureze nakon 12 mjeseci kod PD bolesnika. Kod primatelja bubrežnog
presatka, razine T3 i T4 su porasle nakon transplantacije, uz značajnu pozitivnu korelaciju
između TSH i eGFR nakon šest mjeseci.
Zaključak: Navedeni rezultati govore u prilog povezanosti funkcije štitnjače i ostatne diureze
kao i funkcije bubrežnog presatka te naglašavaju važnost razumijevanja složenog
međudjelovanja između funkcije štitnjače, bubrežne funkcije i modaliteta nadomjesnog
bubrežnog liječenja.Objectives: The interplay between thyroid and kidney function in patients with chronic kidney
disease (CKD) is not yet fully understood. This single-center prospective study aimed to
examine thyroid function in pre-dialysis patients in stages 4 and 5 of CKD, those treated with
peritoneal dialysis (PD), hemodialysis (HD), and kidney transplant recipients (KTRs).
Additionally, we monitored mortality by group, the number of hospitalizations, and the
potential influence of thyroid function on kidney function and the clinical outcomes of patients.
The research was conducted at the Department of Nephrology, Dialysis and Kidney
Transplantation, Clinic for Internal Medicine, Clinical Hospital Center Rijeka.
Patients and Methods: The study included 108 patients: 24 with CKD stage 4 (G4), 19 with
CKD stage 5 not yet on dialysis (G5ND), 18 PD patients, 24 HD patients, and 23 KTRs. The
follow-up period was 24 months, during which thyroid function was assessed by measuring
TSH, T3, fT3, T4, fT4, and thyroid antibodies (antiTPO, antiTg, TSI). The study analyzed the
correlation between thyroid hormone levels and kidney function, as well as residual kidney or
kidney graft function across different patient groups.
Results: In CKD stage 4 and 5ND patients, TSH levels remained within the reference intervals
after 24 months, although changes in T3 and fT4 levels were observed. Notably, CKD stage
5ND patients showed a significant negative correlation between fT4 and creatinine levels. In
PD patients, elevated TSH levels normalized over time, and T4 and fT3 levels were
significantly higher compared to HD patients. Additionally, a positive association was observed
between T4 levels and 24-hour diuresis after 12 months in PD patients. KTRs showed increased
levels of T3 and T4 post-transplantation, with a significant correlation between TSH and eGFR
at six months.
Conclusion: Our results indicate a connection between thyroid function, residual diuresis, and
kidney graft function, highlighting the importance of understanding the complex interactions
between thyroid function, kidney function, and modalities of renal replacement therapy
An expeditious seismic vulnerability assessment method for existing unreinforced masonry buildings
No full textPotresi su prirodne pojave koje se ne mogu spriječiti niti predvidjeti, a iza sebe ostavljaju značajne ljudske i materijalne gubitke. Međutim, takva razorna sila kontinuirano potiče društvo i akademsku zajednicu na razvoj metoda za procjenu potresne otpornosti građevina kako bi se smanjile štete i povećala sigurnost. Nakon nedavnih potresa u Zagrebu i Petrinji, u Hrvatskoj je dodatno porasla svijest o važnosti potresne otpornosti postojećeg građevinskog fonda te su postavljeni temelji za razvoj novih metoda procjene oštetljivosti građevina.
Ovaj rad bavi se procjenom potresne oštetljivosti zidanih nearmiranih zgrada tipičnih za područje grada Zagreba. Pregled literature pokazao je da se oštetljivost značajno razlikuje ovisno o tipologiji gradnje i geografskoj lokaciji, što upućuje na potrebu za razvojem metode specifične za zagrebačku tipologiju zgrada. Stoga je u ovom istraživanju korištena baza podataka prikupljena iz potresa 2020. godine, koja uključuje podatke za 300 oštećenih zgrada te dodatnih 10 zgrada proračunatih numeričkim modeliranjem. Prikupljeni su podaci koji najviše utječu na oštetljivost zgrada poput starosti zgrade, tipologije, vrste konstrukcije i materijala, primjenjenim propisima u vrijeme građenja, održavanju, rekonstrukcijama, o
izvornim i stečenim nedostacima i ostalim parametrima vezanima za tipologiju gradnje. Uz to, identificirano je 17 parametara kao potencijalno najutjecajnih na ponašanje zgrada u potresu. Svaki od parametara kategoriziran je u skupine od A (najpovoljniji utjecaj) do D (najnepovoljniji utjecaj). Analiza podataka provedena je pomoću različitih statističkih metoda, pri čemu se linearnom regresijom dobila najznačajnija analiza koja je izdvojila 9 najutjecajnijih parametara na ponašanje zgrada. Na temelju rezultata definirani su težinski faktori za svaki parametar te je formirana metoda za određivanje indeksa oštetljivosti zgrada. Ova metoda pokazala je značajne razlike u težinskim faktorima i indeksima u usporedbi s postojećim metodama iz literature, pri čemu su novi indeksi bolje korelirali sa stvarnim razinama oštećenja u Zagrebu. Na temelju toga napravljena je ekspeditivna metoda procjene potresne oštetljivosti koja je prilagođena realnim seizmičkim uvjetima i umjerenim potresima karakterističnim za ovo područje. Na kraju, predstavljena je analiza vrijednosti podataka koja prikazuje postupak donošenja odluka temeljen na procesu obnove zgrada oštećenih u potresu. Ova procedura, provedena pomoću stabla odluke, potvrđuje dugoročne prednosti prikupljanja dodatnih informacija u obnovi zgrada različitih veličina.1. Introduction
Living with earthquakes and the fear of them has always been a part of life in the Mediterranean region of Europe. Due to the high seismic risk in this part of Europe, the topic of earthquake engineering has, out of great necessity, been a long-standing focus within the scientific community. Seismic risk consists of three factors: hazard, exposure, and vulnerability. Ultimately, vulnerability is the only parameter that can be influenced. Traditional masonry buildings in Europe are particularly
susceptible to earthquakes due to their inherent characteristics, construction methods, and the materials used, which often fail to meet modern seismic design standards. For that reason, seismic vulnerability assessment methods play a critical role in mitigating this risk. A wide range of methods is available in the literature, most of which are tailored to specific geographic regions, with the choice of method depending on the study's goal, scope, and context. Therefore, developing a expeditious assessment method for the seismic vulnerability of traditional architecture is of utmost importance, as more detailed and sophisticated approaches are usually limited to individual monumental structures. A review of current methods has revealed that each is adapted to a particular building typology, construction material, and geographic context. For this reason, adapting existing methods for assessing seismic vulnerability is essential to address the case of masonry buildings in Zagreb. Based on this, the following hypotheses were defined:
H1: Currently available seismic vulnerability assessment methods for unreinforced masonry
structures are not tailored to the Croatian building typology. Through the development of a new
expeditious method and the adaptation of key parameters, a more accurate vulnerability
assessment will be achieved.
H2: The application of value of information (VoI) analysis in the assessment phase of existing
buildings provides data that supports more cost-effective renovations and a more efficient
decision-making strategy.
2. State-of-the-art
The goal of seismic vulnerability assessment is to determine the probability of a specific damage level occurring for a particular building type during an earthquake of a given intensity. To preserve important historical buildings of specific architectural value and existing urban areas, which predominantly consist of unreinforced masonry structures, it is essential to applya robust large-scale vulnerability assessment methodology. Due to the variety of building archetypes, these methods must be simple, rapid, and reliable i.e., expeditious. Various vulnerability assessment methods proposed in the past can be divided into two main categories: empirical and analytical, both of which can also be utilized in hybrid approaches. Empirical methods are based on extensive datasets collected from buildings in post-earthquake scenarios. These databases are primarily built on data gathered through visual inspections conducted after earthquakes. The data relate to earthquake-induced damage, various building typologies, or vulnerability indices associated with construction characteristics, material types, and building techniques. The most commonly used approach is the Vulnerability Index Method (VIM), which is based on the vulnerability index developed by Benedetti and Petrini in 1984 and later implemented in GNDT in 1993. The vulnerability index represents the sum of parameters weighted by specific factors, where each parameter reflects a particular characteristic of the building. A review of the state of the art reveals that previous research on seismic vulnerability, based on various methods, produces vulnerability functions and indices that are not entirely reliable when applied in other countries. Therefore, existing vulnerability assessment methods must be adapted to account for variations in construction techniques, building typologies, and failure mechanisms. This can only be achieved by utilizing and processing information obtained from post-earthquake investigations conducted in each geographical area.
3.Methodology
This study focuses on unreinforced masonry buildings that form the historic urban centre of the city of Zagreb. These buildings suffered the most damage during recent earthquakes, identifying them as the structures with the highest seismic vulnerability. These buildings are constructed with unreinforced masonry and lime mortar, featuring wooden floor structures or shallow vaults above the basement and ground floors, and wooden roof structures. The damage to buildings in this study was assessed using three methods. The first method involves damage categories from D1 to D5, based on the EMS-98 classification [43]. To evaluate the overall building damage, the level of damage to structural elements is assessed, along with the engineering judgment regarding the extent of this damage. The second method extends the first by introducing intermediate categories, creating five sublevels between the original six categories: D0/D1, D1/D2, D2/D3, D3/D4, and D4/D5. This approach addresses the saturation of buildings classified in damage categories D2 and D3, which commonly result from moderate earthquakes, as well as uncertainties in expert assessments and limitations of the discrete scale, which does not allow for more precise evaluations.
The third method was introduced to address the lack of precision in representing actual damage using a discrete damage scale. To overcome this issue, a continuous damage scale approach was applied, based on the Italian guidelines for cultural heritage [87], which are used for categorizing church damage through failure mechanisms. For each potential damage mechanism, six damage levels are defined, ranging from D0 (no damage) to D5 (partial or complete collapse of the macroelement), as assessed by experts. Starting from the damage levels of each mechanism, a global damage index can be defined, calculated as the weighted average of the active/activated failure mechanisms [88,89]. The global damage index d
for a building is estimated using the following equation:
= 1/ 5 x Σ
=1
where is the number of potential mechanisms, and k is the damage level for each activated mechanism. Failure mechanisms (walls, non-structural elements, floor structures, staircases, gables, and roofs) for unreinforced masonry buildings were identified based on the observed damage to Zagreb's building typology during the 2020 earthquake. These were categorized in accordance with the Italian guidelines [88] and the distribution of building elements.
To develop a seismic vulnerability assessment method, 17 parameters have been identified as potentially having the greatest influence on the seismic behavior of unreinforced masonry buildings. Each parameter will be assigned a category ranging from A (most favorable) to D (least favorable) and incorporated into a building database. Based on this data, detailed analyses will be conducted to determine which parameters have the most significant impact on the seismic performance of unreinforced masonry buildings. A state-of-the-art review highlighted 17 parameters derived from three different methods, along with two additional parameters introduced based on failure mechanisms observed during the 2020 Zagreb earthquake. All ten parameters (P1-P10) from the vulnerability index method developed by Benedetti and Petrini [40] were included, as they collectively form a comprehensive approach covering all key building elements. Three parameters (V5, V7, V10) from Vicente's method [72] were utilized, focusing on the global behavior of the building, including the number of stories, interaction between buildings within a block (aggregate), and the influence of openings on the behavior of street façades. Two parameters related to out-of-plane wall failure, slenderness and wall span (J1 and J2) were taken from the SAVVAS method [63]. Finally, through the collection and analysis of data from the 2020 earthquake, the most common failure mechanisms specific to Zagreb“s building typology were identified. To address the shortcomings of existing methodologies for the Croatian scenario, two additional parameters were introduced: the parameter for gable walls (Z1) and the parameter for staircases (S1).
The compilation of a database represents a crucial step in research related to the seismic vulnerability assessment of masonry buildings. The collected data provides a representative sample that enables a detailed analysis of masonry buildings behavior during earthquakes and serves as the foundation for developing and validating vulnerability assessment methods. For the purposes of this study, data for a total of 300 buildings were collected, covering 17 different parameters. Processing these parameters is essential for understanding the influence of individual building characteristics on their seismic vulnerability. The analysis identifies the factors contributing to the level of damage, thus laying the groundwork for further development of seismic vulnerability assessment method. Through data analysis of the current database, in terms of distribution, it was concluded that the amount of data on real buildings in some categories is below the desired level. To define a robust regression model that enables reliable assessment of parameter weights, the database was expanded with numerical models. Therefore, it was necessary to create numerical models to achieve a more balanced distribution of buildings belonging to different classes for certain parameters and to make the analysis more comprehensive. To supplement the database with numerical analyses, parameters related to façade openings and floor systems were included. The façade opening parameter (V10) was selected due to a lack of data in the existing database, which limited the analysis. On the other hand, the floor system parameter (P7) was added because of its potential significance for seismic building performance, even though its distribution in the database was sparse. The pushover analysis method is used to assess the seismic behavior of masonry buildings due to its ability to identify potential weaknesses in the structure and predict how the building will respond to seismic forces [48,94].
5. Data analysis
The processing and analysis of data collected in the database are presented with the aim of gaining insights into the seismic behavior of buildings. The approach is based on the analysis of a large database using several statistical methods, Boruta package, Stepwise selection method, with regression analyses being the most significant. One of the main outcomes of the regression analysis is the determination of regression coefficients, which can be used to compare the relative importance of the parameters included in the calculation of the seismic vulnerability index. These coefficients can then be associated with the weighting factors of the seismic vulnerability assessment parameters, enabling their numerical definition. By applying these methods, a deeper understanding of the relationship between damage and key parameters will be achieved, serving as the foundation for the calibration of current methods. In this case, due to the presence of multiple input variables and discrete damage values, it is essential to use multiple logistic regression analysis.
To validate the model and assess statistical significance, the coefficient of determination R 2 and the model's p-value are evaluated. Across 33 models, various methods and analyses were employed, incorporating different classifications of damage and parameters. Ultimately, through different combinations of the most influential parameters and the process of reducing the number of variables, three final models were developed. These models will serve as the foundation for creating different versions of the vulnerability index, with regression coefficients obtained through linear regression. These models provide a basis for developing an index that quantifies the level of building damage. The final formulation is presented in Table 24, while a comparison of the adopted weighting factors with other methods is shown in Table 23.
Table 24 Formulation of expeditious method for vulnerability assessment
[***Display of the table please look up inside]
To include expert opinions with the aim of understanding and defining the weighted factors for parameters in the expeditious method, a survey was conducted. The weighted factors derived in this way can be compared with values obtained using a statistical approach based on empirical data. The survey was created using the digital platform Fill out Forms and conducted
online, facilitating distribution among experts worldwide. In this study, the survey was distributed, and responses were collected from a total of 111 experts working to varying degrees in the field of earthquake engineering and masonry structures. The majority of participants were from academia, including professors, researchers, and students, with doctoral and master's students among them. Additionally, a significant number of professionals from the industry, specializing in design and construction in Croatia, participated in the survey. The survey asked participants to rank all parameters from the most influential to the least influential, providing an average rating for each parameter along with explanations for the most and least influential ones. Another type of question required participants to rate different groups of building parameters on a scale of 1 to 5, serving as a control to validate the rankings. The survey also included a pairwise comparison, where participants identified which of two proposed parameters was more influential and evaluated the relative importance of the chosen parameter. Based on the average ratings from the survey, the ranking and influence of individual parameters were analyzed. The consistency of the rankings was confirmed by responses to the other survey questions. To enable easier comparison with parameter rankings derived from statistical methods based on empirical data, the average ratings were normalized and converted into weighted factors. A comparison of these derived weighting factors with those from existing methods is presented in Table 23.
Table 23 Comparison of weighted parameters
[***Display of the table please look up inside]
6. Value of Information (VoI)
In Croatia, the majority of unreinforced masonry buildings have exceeded their intended design lifespan. For this reason, it is crucial to have a decisive and efficient plan for assessment and maintenance that provides the highest possible utility (health, safety, financial feasibility, sustainability, functionality). The aim of this study is to examine the role of different levels of post-earthquake condition assessment through Value of Information (VoI) analysis of existing masonry buildings. The study focuses on existing buildings to evaluate the benefits of condition assessments in terms of structural economy, safety, and the preservation of cultural value. It is illustrated how prior decision analysis can help quantify the VoI obtained from assessing the condition of masonry buildings, thereby aiding in selecting appropriate post-earthquake assessment procedures and subsequent maintenance actions. VoI analysis is conducted using Excel spreadsheets and is represented by a characteristic decision tree for each building. The results for all residential buildings with floor areas ranging from 300 to 2,100 m² are summarized in Table 28. This study demonstrates utility in economic terms, specifically the costs of strengthening buildings based on the chosen level of assessment. To quantify the reduction in uncertainty achieved through some form of data collection, the maximum utility value must be subtracted from the prior utility value when no additional data is provided. The analysis results in Table 28 show that Level 3 condition assessment is the optimal strategy for
evaluating residential masonry buildings in terms of cost and benefits for owners and occupants. The Value of Information (VoI) analysis highlights the utility of additional information and data collected for condition assessments, particularly in the
context of designing reconstruction projects and subsequent building maintenance.
Table 28 Results of VoI analysis
[***Display of the table please look up inside]
7. Conclusion and future recommendations
The data analysis was conducted using various statistical methods, with linear regression providing the most significant results by identifying the 9 most influential parameters affecting building behavior. Based on these results, weighted factors were defined for each parameter, and a method was developed for determining the damage index of buildings. This method revealed significant differences in weight factors and indices compared to existing methods in the literature, with the new indices showing better correlation with the actual damage levels observed in Zagreb. As a result, an expeditious method for assessing seismic vulnerability was developed, tailored to the realistic seismic conditions and moderate earthquakes characteristic of this region. Finally, a Value of Information (VoI) analysis was presented, showcasing the decision-making
process for the reconstruction of earthquake-damaged buildings. This procedure, carried out using a decision tree, demonstrates the long-term benefits of collecting additional information during the reconstruction of buildings of various sizes. Given that earthquakes are random natural events beyond our control in terms of occurrence or intensity, the proposed future research includes the following: expanding the database with data from new projects, developing a database for buildings affected by the earthquake in Petrinja and its surrounding areas, conducting extensive numerical analyses, including applying a hybrid method as described in [62], which allows for combining earthquake data to calibrate numerical models. Based on these calibrated models, complex numerical analyses could be conducted. This approach would enable the prediction of building behavior across a wide range of earthquake intensities, including those not directly observed
Activation mechanism of MntR protein from the bacterium Halakalibacterium halodurans for DNA binding
No full textHalalkalibacterium halodurans je industrijski važna alkalofilna bakterija koja, da bi preživjela, zahtijeva precizan i osjetljiv regulacijski mehanizam održavanja homeostaze iona mangana (Mn2+). Ključni protein u regulacijskom mehanizmu bakterije H. halodurans je MntR - transkripcijski faktor koji selektivno veže ione Mn2+ i posljedično DNA, regulirajući time gensku ekspresiju proteina uključenih u homeostazu Mn2+. Simulacije molekulske dinamike u trajanju 400-1200 ns korištene su za proučavanje strukturnih i dinamičkih svojstava različitih formi proteina s obzirom na prisutnost Mn2+ iona u veznom mjestu. Kada MntR ima Mn2+ u veznom mjestu, dolazi do približavanja DNA-veznih domena te rigidnije konformacije proteina. Takav protein ostvaruje specifične i stabilne interakcije u simulacijama s DNA. MntR u slobodnoj formi zauzima širu i fleksibilniju strukturu, koja se na DNA veže nespecifičnim i kratkoživućim interakcijama. Time je slobodnom proteinu omogućeno lateralno kretanje duž DNA, do trenutka vezanja Mn2+ u vezna mjesta i aktivacije proteina za specifično vezanje u velike utore DNA.Halalkalibacterium halodurans is an industrially important alkalophilic bacterium that, in order to survive, requires a precise and sensitive regulatory mechanism to maintain homeostasis of manganese ions (Mn2+). The key protein in the regulatory mechanism of the bacterium H. halodurans is MntR - a transcription factor that selectively binds the Mn2+ ion and consequently DNA, thereby regulating gene expression of proteins involved in Mn2+ homeostasis. Molecular dynamics simulations lasting 400-1200 ns are used to study the structural and dynamic properties of different protein forms with regard to the presence of Mn2+ ions in the binding site. When MntR has Mn2+ in its binding site, the DNA-binding domains come closer, and the conformation of the protein becomes more rigid. Such a protein achieves specific and stable interactions in simulations with DNA. In its free form, MntR occupies a wider and more flexible structure, which binds to DNA through non-specific and short-lived interactions. This enables the free protein to move laterally along the DNA, until the binding of Mn2+ in the binding sites activates the protein for specific binding in the large grooves of DNA