National Center for External Evaluation of Education

Zagreb, Croatia

National Center for External Evaluation of Education

Zagreb, Croatia
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Dautovic J.,Ruder Boskovic Institute | Vojvodic V.,Ruder Boskovic Institute | Tepic N.,National Center for External Evaluation of Education | Cosovic B.,Ruder Boskovic Institute | Ciglenecki I.,Ruder Boskovic Institute
Science of the Total Environment | Year: 2017

Dissolved organic carbon (DOC) is an essential component of the biogeochemical marine system, effecting biological and chemical reactions that take place in the sea. DOC represents a dynamic component of the global carbon cycle. This paper reports 25 years of measurements of DOC content and distribution at seven stations along the transect Po River delta – Rovinj in the northern Adriatic (NA). The results show strong temporal and spatial variability: (1) The highest average DOC concentrations were observed in 1998 and 2002 (143 μmol/L and 137 μmol/L, respectively); (2) The minimum average DOC was recorded in 2006 (88 μmol/L) and (3) The short-term DOC accumulation (up to 203, average 102 μmol/L) for the years 2009 to 2012, was observed during the summer and autumn months followed by unusually low DOC concentrations during the winter and spring. The DOC results from the more recent monitoring at the same stations indicate primarily oligotrophic characteristics of the NA seawater (88 μmol/L). The results of DOC variability and distribution in the NA appears to be strongly influenced by complex circulation patterns. This paper provides a “link” between the Ionian circulation and the NA ecosystem as a part of the recently identified Adriatic-Ionian Bimodal Oscillating System (BiOS). A good agreement between the BiOS oscillation and other variables related to the DOC concentration, like the NA A and B winter types, the Po River discharge, salinity, chlorophyll a, occurrence of hypoxic-anoxic conditions, eutrophication and oligotrophication, suggests that DOC might be a good tool and indicator of global change. © 2017 Elsevier B.V.


Djakovic I.,University of Zagreb | Rudman S.S.,University of Zagreb | Gall V.,University of Zagreb | Kosec A.,University of Zagreb | And 2 more authors.
Acta Clinica Croatica | Year: 2016

The incidence of pregnancy related diabetes has been steadily increasing during the past decade. The aim of this retrospective study was to evaluate the type and prevalence of gestational diabetes complications after implementing new diagnostic criteria for gestational diabetes. The incidence of gestational diabetes, maternal age, mode of delivery and birth weight were analyzed. Study patients were divided into three groups. The first group consisted of patients who gave birth during 2005, the second group during 2011 and the third group during 2012. In 2005, the World Health Organization criteria were used on diagnosing gestational diabetes, whereas in 2011 and 2012 the criteria issued by the International Association of Diabetes and Pregnancy Study Groups were considered. There was no statistically significant difference among the groups according to maternal age, birth weight (p = 0.203) and mode of delivery (p = 0.883). Cesarean section was performed in about 30% of deliveries in all groups combined. There was no significant difference in the number of neonatal hypertrophy (p = 0.348), although the distribution of hypertrophy showed a tendency towards higher values in 2005. The incidence of gestational diabetes was 2.2% in 2005, 6.6% in 2011 and 12% in 2012. In conclusion, difference in the incidence of pregnancy related diabetes appeared to have resulted directly from using different diagnostic criteria. The new criteria contributed to a relatively higher incidence of gestational diabetes but also achieved better gestational glycemic control and consequently better fetal growth regulation.


Cukrov N.,Ruder Boskovic Institute | Tepic N.,National Center for External Evaluation of Education | Omanovic D.,Ruder Boskovic Institute | Lojen S.,Jozef Stefan Institute | And 3 more authors.
International Journal of Environmental Analytical Chemistry | Year: 2012

Multivariate statistical analyses were applied on the measured physico-chemical (Cd, Pb, Cu, Zn, Mg, Ca, O2, alkalinity, temperature, pH, SAS, DOC and DIC) and isotopic parameters (δ13C and δ18O) to estimate and distinguish anthropogenic from natural influences to the water system of the Krka River. Analyses were conducted on the data collected during six years from twelve sampling sites. On the basis of orientation, positioning and grouping of parameters arranged by biplots, four main hypotheses were defined and finally statistically confirmed. Thereof, two main and distinct processes occurring in the Krka River could be highlighted: (i) upstream pollution, caused by the inflow of untreated waste-waters of city of Knin and (ii) downstream self-purification, caused by the sedimentation and/or co-precipitation of pollutants coupled by the inflow of clean subterranean water (groundwater recharge). Grouping of (i) hydrological and carbon cycle connected parameters, and (ii) anthropogenically influenced correlated parameters were proposed as a result of statistical analysis. Regarding the pH, it is shown that a stream section influenced by the subterranean inflow of Zrmanja River is statistically significantly different for all sampling campaigns during six years, being lower for about 0.5 pH unit. © 2012 Copyright Taylor and Francis Group, LLC.


Mikulic K.,Association BIOM | Radovic A.,University of Zagreb | Kati V.,University of Patras | Jelaska S.D.,University of Zagreb | Tepic N.,National Center for External Evaluation of Education
Community Ecology | Year: 2014

Land abandonment is a widespread phenomenon in agricultural systems, especially in former communist countries of Eastern and South-eastern Europe. Moreover, Croatia was affected by acts of war which enhanced the depopulation of marginal areas impelling further land abandonment. Agricultural landscapes in Croatia are highly parcelled with various proportions of forest habitats due to traditional smallholder farming systems. Secondary successions as a consequence of land abandonment affect farmland birds that are among the most endangered bird species in Europe. We examined bird communities along a habitat gradient in heterogeneous agricultural landscapes. We used the share of woody vegetation cover as a proxy measure for land abandonment that we classified in four classes. Our results showed no significant Shannon Wiener Index differences of bird communities along the land abandonment gradient. However, there were differences in abundances when we examined bird guilds such as farmland, forest and "other" birds separately. However, the conservation value of each of the four land abandonment classes did not show significant differences. We extracted single bird species such as the Yellowhammer (Emberiza citrinella), Red-backed Shrike (Lanius collurio), Song Thrush (Turdus philomelos) and European Robin (Erithacus rubecula) as potential indicator species for the four examined land abandonment levels. With these four species we successfully modelled the distribution of the recorded bird assemblages at the plot level along the four vegetation succession stages. We emphasized the need to develop new and integrative land use management concepts for areas affected by land abandonment in order to formulate sound conservation policy. © Akadémiai Kiadó, Budapest.


Radovic A.,University of Zagreb | Bukovec D.,Croatian Natural History Museum | Tvrtkovic N.,Croatian Natural History Museum | Tepic N.,National Center for External Evaluation of Education
International Journal of Sustainable Development and World Ecology | Year: 2011

The authors researched changes in specific habitat types in areas considered to be the most important in Croatia for protection of endangered bird fauna during the period 1990-2000. The analysis focused on four areas in the continental part of Croatia (Danube and Drava River alluvium, Pokupsko depression, Sava River basin, Upper Drava River basin) and four areas in the Mediterranean part (Neretva River estuary, NW part of North Dalmatia, Pasko field, Lake Vrana). For the classified habitat types, changes in Corine land cover databases in 1990 and 2000 were analysed. The greatest changes in habitat were detected along the Danube and Drava River alluvium, where more than 8% of the total area changed habitat type, as well along the Sava River basin, where approximately 5% of the total area and the greatest absolute area changed habitat type. The most pronounced changes were detected in forest habitats, where forest degradation prevents the maturation of forest stands. The authors discuss which bird species listed in the Red Data Book of Birds of Croatia may be most impacted by the detected changes in habitat. Special attention was given to a comparison of habitat changes in the Nature Park Lonjsko polje between two raptor species, Aquila pomarina and Haliaeetus albicilla, according to the suitability of habitats where changes occurred. © 2011 Taylor & Francis.


Radovic A.,University of Zagreb | Nikolov S.C.,Bulgarian Society for the Protection of Birds | Tepic N.,National Center for External Evaluation of Education | Mikulic K.,Association BIOM | And 2 more authors.
Folia Zoologica | Year: 2013

The abandonment of less productive agricultural land and the intensification of agricultural land use are the main features of the Common Agricultural Policy (CAP) that Croatia will enforce now as new member of the EU. Due to demographic changes and the economic transition in Croatia resulting from war in the 1990s, substantial tracts of agricultural land were abandoned. We investigated two habitat types in the protected floodplain landscape of Lonjsko polje in the continental part of the country: arable land and pastures. Both habitats were maintained by agricultural management and suffered from partial abandonment. Land abandonment increased the susceptibility to encroachment by the invasive plant species Amorpha fruticosa. Data on bird communities were obtained during the breeding season in 2010 while there were high water levels in the floodplain. Data were collected from 63 points, and a total of 1447 individuals from 70 species were recorded during the study. We found that the bird community structure was primarily related to the presence/abandonment of agricultural land use and the habitat type. Further, we detected that the bird community structure in the same habitat type differed by management intensity. Open habitat specialists were most influenced by land abandonment. However, the conservation value (according to the Species of European Conservation Concern value, SPEC) of grazed pastures and abandoned pastures did not differ significantly, in part because the overgrown pastures with high water levels were found to be suitable for Acrocephalus species. The shift in bird community structure between abandoned and managed arable lands were smaller than those detected in the pastoral communities. Because land abandonment is a widespread phenomenon in Croatia, we emphasize the urgent need for a nationwide monitoring program for farmland birds to register the resulting changes in farmland bird communities and to develop appropriate agri-environment measures to mitigate the process.


Habus-Korbar A.,National Center for External Evaluation of Education | Tepic N.,National Center for External Evaluation of Education | Culig B.,University of Zagreb | Luzar-Stiffler V.,University of Zagreb
Journal of Computing and Information Technology | Year: 2011

Cluster analysis was used to create segments of high school graduates based on their motivations/opinions regarding their future education. Data for this study were collected using a questionnaire distributed to high school graduates following State Matura exam. The students were asked to evaluate the importance of 13 different reasons/causes for choosing the faculty selected as their first choice. The analysis yielded five meaningful clusters of students that differ not only in motivations, but also in achievement on State Matura exams and in their preference regarding the scientific field of their future study.


Dragun Z.,Ruder Boskovic Institute | Tepic N.,National Center for External Evaluation of Education | Krasnici N.,Ruder Boskovic Institute | Teskeredzic E.,Ruder Boskovic Institute
Environmental Science and Pollution Research | Year: 2016

The study of metal bioaccumulation in the gills of European chub (Squalius cephalus) was conducted in September 2009 at the medium-sized rural river Sutla, characterized by agricultural and municipal type of water contamination. The concentration ranges were established for the first time in the soluble, metabolically available fractions of chub gills for 12 metals, which are environmentally extremely relevant and yet only seldom studied, as follows in a decreasing order: K, 225–895 mg L−1; Na, 78–366 mg L−1; Ca, 19–62 mg L−1; Mg, 13–47 mg L−1; Rb, 164–1762 μg L−1; Sr, 24–81 μg L−1; Ba, 13–67 μg L−1; Mo, 1.3–16 μg L−1; Co, 0.7–2.7 μg L−1; Li, 0.4–2.2 μg L−1; Cs, 0.2–1.9 μg L−1; and V, 0.1–1.8 μg L−1. The concentrations of Fe (1.6–6.4 mg L−1) and Mn (16–69 μg L−1) were also determined and were in agreement with previous reports. By application of general linear modelling, the influence of different abiotic (metal exposure level) and biotic parameters (fish sex, age, size and condition) on metal bioaccumulation was tested. It was established that bioaccumulation of many metals in fish depended on various physiological conditions, wherein Ba could be singled out as metal exhibiting the strongest association with one of biotic parameters, being significantly higher in smaller fish. However, it was also undoubtedly demonstrated that the concentrations of three metals can be applied as reliable indicators of metal exposure even in the conditions of low or moderate water contamination, such as observed in the Sutla River, and those were nonessential elements Li and Cs and essential element Fe. The results of our study present an important contribution to maintenance of high ecological status of European freshwaters, through enrichment of knowledge on the bioaccumulation of various metals in gills of European chub as frequently applied bioindicator species in monitoring of water pollution. © 2016 Springer-Verlag Berlin Heidelberg


Gasparovic B.,Ruder Boskovic Institute | Djakovac T.,Ruder Boskovic Institute | Tepic N.,National Center for External Evaluation of Education | Degobbis D.,Ruder Boskovic Institute
Continental Shelf Research | Year: 2011

Surface-active organic substances (SAS), nutrients, chlorophyll a (Chl a), dissolved oxygen (O2), salinity (S) and temperature (T) were measured approximately monthly in the northern Adriatic Sea (NA) during two years. Results were elaborated for two stations of different trophic status. Exhaustive statistical examinations of measured variables were performed to contribute to better understanding of the processes and interdependence of the measured parameters. The results of those analyses allowed the region to be described based on several groups of data relevant for particular processes. Chl a appear to be independent parameter; orthosilicate, nitrite and ammonium represent the parameter group most relevant for regeneration processes; the second group includes nutrients dominant in freshwater inputs (orthophosphate and nitrate), while in the third group are parameters related to primary production processes (T, O2, organic phosphorus and SAS). Probably due to time lags between nutrient uptake and phytoplankton growth as well as between cells growth/division and SAS release, both, the correlation between nutrients and Chl a and the correlation between Chl a and SAS were not statistically significant. Although significantly higher nutrient and Chl a concentrations were found in the mesotrophic western part of the region in comparison to the oligotrophic eastern part, the SAS concentration differences were less marked. It is assumed that more OM is produced, but also at the same time remineralized, at the mesotrophic western part, leading to higher concentrations of regenerated nutrients there. Presence of different phytoplankton taxa and/or fractions (micro and nano) at the two stations may have also contributed to minimize the difference in SAS contents. Higher SAS acidities were noticed in the mesotrophic than in the oligotrophic part. © 2011 Elsevier Ltd.


Gasparovic B.,Ruder Boskovic Institute | Godrijan J.,Ruder Boskovic Institute | Frka S.,Ruder Boskovic Institute | Tomazic I.,Ruder Boskovic Institute | And 8 more authors.
Marine Environmental Research | Year: 2013

A systematic investigation of non-phosphorus containing glycolipids (GL) was conducted in the northern Adriatic Sea during two years at two stations with different nutrient loads. GL concentration varied both spatially and temporally, with values of 1.1-21.5μg/L and 0.4-44.7μg/L in the particulate and the dissolved fraction, respectively. The highest concentrations were measured during summer in surface waters and at the more oligotrophic station, where GL yields (% of total lipids) were often higher than 20% and 50% in the particulate and dissolved fractions, respectively. To obtain more insight into factors governing GL accumulation autotrophic plankton community structure (pico-, nano- and microplankton fractions), chlorophyll a, heterotrophic bacteria and nutrient concentrations were measured together with hydrographic parameters and sunlight intensity. During the investigated period smaller autotrophic plankton cells (pico- and followed by nanoplankton) prevailed in abundance over larger cells (microplankton), which were found in large numbers in freshened surface samples. Several major findings resulted from the study. Firstly, during PO4 limitation, particularly at the oligotrophic station, enhanced glycolipid instead of phospholipid accumulation takes place, representing an effective phosphate-conserving mechanism. Secondly, results suggest that at seawater temperatures 19°C autotrophic plankton considerably accumulate GL, probably to achieve thermal stability. Thirdly, high sunlight intensities seem to influence increased GL accumulation; GL possibly plays a role in cell mechanisms that prevent/mitigate photooxidation. And finally, substantial accumulation of GL detected in the dissolved fraction could be related to the fact that GL do not contain biologically relevant elements, like phosphorus, which makes them an unattractive substrate for enzyme activity. Therefore, substantial portion of CO2 could be removed from the atmosphere in P-limited regions during summer via its capture by plankton and conversion to GL. © 2013 Elsevier Ltd.

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