The Dinaric karst in the north differs from the rest of the karst in Croatia in terms of karstification depth. The infiltrating precipitation drains in cascades from deeply karstified mountainous ...areas to the shallow or fluviokarst, forming the tributaries of the Kupa River. Time series analyses were conducted on a 5-year dataset to elucidate the hydrogeological conceptual model of the area and clarify disparate findings from tracer tests under varying hydrological conditions. The flow duration curve, autocorrelation functions, and recession curves were used to evaluate the spring discharge variability, the karstification degree, and the karst aquifer’s size. The crosscorrelation function and temperature dynamics were employed to assess the spring’s response to recharge and the hydrogeological system behavior. Comparative analysis with previous studies was conducted to contextualize the obtained results. The research outcomes delineated several key findings: (i) the deep karst zone is less developed than the shallow karst zone; (ii) groundwater exchange is significantly faster in shallow karst; (iii) groundwater divides in the Kapela Mountain are zonal; (iv) the homogenization of groundwater occurs during periods of high water levels; (v) fast water exchange transpires without concurrent groundwater temperature homogenization; and (vi) a definition of the boundary between deep and fluviokarst in Croatia.
Cilj rada je prikazati kakve se promjene događaju na mrežnici oka u uznapredovaloj dobi.Sa starenjem se kvaliteta vida smanjuje čak, i kada nema nikakvih očnih bolesti. U starijoj dobi događaju se ...promjene na pripadajućoj žilnici, mrežničkim krvnim žilama, mrežnici i to naročito na mrežničkom pigmentnom epitelu, ganglijskim stanicama i neuroepitelnim stanicama. Kako sa starenjem propadaju svi dijelovi oka, tako i sama mrežnica, te joj se smanjuju mnoge vidne funkcije, što se odražava na kvalitetu života.
U radu su predstavljeni rezultati malakološkog istraživanja rijeke Mrežnice. Sastav mekušaca ove rijeke proučavan je na području od Vojnog poligona Eugen Kvarternik do njenog utoka u Koranu blizu ...Karlovca, u razdoblju 2013. – 2018. ukupno je pronađeno 29 vrsta vodenih mekušaca (19 puževa, 10 školjkaša). Na većini lokaliteta dominirali su Theodoxus danubialis, Esperiana esperi, Microcolpia daudebartii i Holandriana holandrii. Sastav vrsta bio je vrlo sličan onom utvrđenom u prethodnom istraživanju rijeke Korane. Zabilježene su populacije ugroženih školjkaša Unio crassus i Pseudanodonta complanata. Na jednom od lokaliteta pronađena je veća populacija ugroženog puža Anisus vorticulus. Od alohtonih vrsta u ovom istraživanju rijeke Mrežnice potvrđena je jedino Physa acuta.
Tijekom evolucije osjetilo vida prošlo je mnoge prilagodbe te se razlikuje od vrste do vrste. Mnoge je oduvijek zanimalo zašto i kako vidimo te kako vide druge vrste oko nas. Svakodnevno se provode ...istraživanja koja su odgovorila na većinu tih pitanja, ali isto tako se dolazi i do novih otkrića koja postavljaju nova pitanja na koja treba odgovoriti. U ovom su radu opisane glavne razlike između oka riba i oka sisavaca te karakterističan nalaz na mrežnici tri vrste riba: špar (Diplodus annularis), trlja od blata (Mullus barbatus) i lastavica glavulja (Chelidonichthys lastoviza). Isto tako, u radu se raspravlja o značenju uočenih promjena.
The Mrežnica River near Duga Resa (Croatia) serves as an ideal ”natural laboratory” for studying downstream transport of material in river systems. This study expands the so-far brief knowledge about ...magnetic and chemical properties of sediments along the lower course of this river, contaminated by discharge of coal slag and ash from a former textile factory, directly released into the river for 110 years (1884–1994). Magnetic susceptibility of the river sediments is very high close to the pollution source and shows a decreasing trend downstream, still being above the level of unpolluted sediments just before the confluence with the Korana River app. 7 km away from the point source. Thermomagnetic curves reveal magnetite as the dominant magnetic mineral, and low-frequency-dependent susceptibility indicates an anthropogenic origin. Most heavy metals and other elements in the sediments show a decreasing trend in the downstream direction, similar to the magnetic concentration signal. Correlation analysis between magnetic susceptibility and concentrations of 29 elements shows strongest correlations with Co (
R
= 0.70), Fe (
R
= 0.92), Sr (
R
= 0.86), Al (
R
= 0.74), U (
R
= 0.78) and B (
R
= 0.96). Cluster analysis distinguishes three clusters: Cluster 1 is under strong influence of contamination and contains four sampling sites; Cluster 2 has extreme values of Cd, Cr, Mo and Ni and contains seventeen sites; Cluster 3 reflects rather clean sites and contains nine sites. According to existing sediment quality criteria, Ni and Cr show the largest degree of contamination among six evaluated heavy metals. Strong variability in the data and frequent extremes are to a large degree caused by heterogeneity in the spatial distribution of the coal-derived material. To account for this situation and to resolve the variability in more detail, statistical sampling of sediments in river cross sections and estimation of the sediment volume are needed, being a target for further research.
The River Mreznica (64 km) is a watercourse in the region of Central Croatia. In the valley of the Mreznica, the forms of the relief created by erosion and deposits present an important basis for ...tourism development. This paper explores their appeal (attractiveness). In terms of tourism, about 10 per cent of the direct resources have already been valorised, while the remaining resources represent potential tourist attractions. The real tourist attractions are located in the lower valley, whereas the potential attractions are found in the middle and upper river valley. Access to potential attractions and their valorisation in tourism is impeded by the spreading of the underbrush, which has advanced considerably over the past twenty years, and by the fact that the upper valley is located in the zone of the “Eugen Kvaternik” Military Polygon. Travertine barriers, which have created a specific type of waterfalls and cascades, together with mills, bridges and ferries, characterise the tourist attractions in the valley of the River Mreznica.
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