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Search Results: 1 - 10 of 461890 matches for " Tja?a Kandu? "
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Characterisation of suspended matter in river systems: River Sava in Slovenia case study
Tjaa Kandu
Geologija , 2011,
Abstract: δ13C and δ15N values in suspended matter were used to examine the seasonal (late summer 2004 and spring 2005) relationship with hydrological characteristics of the River Sava watershed in Slovenia. d13C values range from - 29.2 to - 23.0 ‰ and δ15N values from 0.5 to 16.7 ‰ and indicate that the samples are a mixture of two end members: modern soils and plant litter. A simple mixing model was used to indicate that soil organic carbon prevails over plantlitter and contributes more than 50 % of suspended material. The total suspended solid flux (TSS) is estimated to be 1.3 × 1012 g/year. Anthropogenic impact was detected only in a tributary stream of the River Sava which is located in an agriculture-industrial area and is reflected in higher δ15N values in suspended matter in the late summer season.
Hydrogeochemical characteristics of the River Idrijca (Slovenia)
Tjaa Kandu
Geologija , 2008,
Abstract: The hydrogeochemical and isotope characteristics of the River Idrijca, Slovenia, where the world’s second largest mercury (Hg) mine is located, were investigated. The River Idrijca, a typical steep mountain river has an HCO3- - Ca2+ - Mg2+ chemical composition. Its Ca2+/Mg2+ molar ratio indicates that dolomite weathering prevails in the watershed. The River Idrijca and its tributaries are over saturated with respect to calcite and dolomite. The pCO2 pressure is up to 13 times over atmospheric pressure and represents a source of CO2 to the atmosphere. δ18O values in river water indicate primary control from precipitation and enrichment of the heavy oxygen isotope of infiltrating water recharging the River Idrijca from its slopes.The δ13 CDIC values range from 10.8 to 6.6 ‰ and are controlled by biogeochemical processes in terrestrial environments and in the stream: 1) exchange with atmospheric CO2, 2) degradation of organic matter, 3) dissolution of carbonates, and 4) tributaries. The contributions of these inputs were calculated according to steady state equations and are estimated to be -11 %: 19 %: 31 %: 61 % in the autumn and 0 %: 6 %: 9 %: 35 % in the spring sampling seasons.
Hydrogeochemical characteristics of the River Sava watershed in Slovenia
Tjaa Kandu,Nives Ogrinc
Geologija , 2007,
Abstract: The River Sava is a typical HCO3- – Ca2+ – Mg2+ River. Total alkalinity increases in the part of the watershed composed of carbonate and clastic rocks, which are less resistant to weathering processes. Ca2+/Mg2+ ratios are around 2 in the carbonate part of the watershed and increase in the watershed composed of carbonate and clastic rocks, indicating dissolution of calcite with magnesium. According to PHREEQC for Windows calculations, the River Sava and its tributaries are oversaturated with respect to calcite and dolomite. δ18OH2O and δDH2O are related to the meteorological patterns in the drainage basin. River water temperatures fluctuate annually following air temperatures.The relationship between the temperature and δ18OH2O and δDH2O values primarily reflects the strong dependenceof δ18O and δD on precipitation and evaporative enrichment in heavy oxygen and hydrogen isotopes of infiltrating water recharging the River Sava from its slopes.The δ13CDIC values are controlled by processes in the terrestrial ecosystem and stream proces-ses such as: (1) dissolution of carbonates, (2) soil derived CO2, and (3) equilibration with atmospheric CO2. Lower δ13CDIC values are observed in the spring sampling season due to abundant precipitation related to soil leaching of CO2 in the river system. From discharge and concentration measurements of sulphate and according to the drainage area of the River Sava basin, the annual sulphur fluxat the border with Croatia was estimated to be 1.4 × 107 g SO4/km2. Assuming that the sources of SO42- to the Sava are its tributaries, precipitationand other sources, the contributions of these inputs were calculated according to steady state equations and estimated to be 52 : 8 : 40 %, respectively. Other sources are attributed to human influences such as industrial pollution and oxidation of sulphides.
A contribution to petrology of dark grey to black interbeds within Upper Permian and Triassic carbonate rocks in the area between Ljubljana and Bloke, Central Slovenia
Stevo Dozet,Tjaa Kandu,Milo? Marki?
Geologija , 2012,
Abstract: This paper presents results of macroscopic, microscopic, chemical, and isotopic investigations of 12 samples ofdark grey to black coloured interbeds occurring within Upper Permian and Triassic lime-, dolo- and marlstones inan area of Outer Dinarides between Ljubljana and Bloke in Central Slovenia. An additional sample is anthracite ofthe Carnian age from the Orle locality. Concentration of Corg in four samples is below 1 %, and in seven samples itvaries between 1 and 2.3 %. Only in one sample, in the black Carnian limestone of the Lesno Brdo area, it is somewhathigher than 5 %. The highest Corg content, 30.61 %, was analysed in the Orle anthracite.Chemical analysis of major elements (as oxides) showed that four samples are clearly siliciclastic mudrocks,with 65–80 % SiO2 + Al2O3. Three samples are typical calcite rich – dolomite poor rocks, with high loss on ignition(LOI about 40 %) derived from calcite decomposition. Four samples are calcite – dolomite characterized rocks withLOI of 34–43 %. One sample, from the Slugovo quarry, is composed of quartz, dolomite and calcite. The anthracitesample from Orle has inorganic matter composed almost exclusively of SiO2 + Al2O3 (clays), and some iron and sulphurwhich form pyrite.Isotopic composition of the calcite carbon ranges from δ13CCaCO3 -5.7 to 1.9 ‰, whereas isotopic composition ofthe organic carbon varies between δ13Corg -34.7 and -21.6 ‰. The most negative δ13Corg value of -34.7 ‰ was analysedin a sample, which is the most organic-rich limestone. Isotopic investigations of nitrogen, expressed by δ15N values,also did not express notable differences in respect to lithology. They vary between 4.6 and 9.1 ‰.Microscopy of polished surface samples showed clearly fine grained siliciclastic, carbonate and coal compositionof the treated rocks.
Geochemical characteristics of surface waters and groundwaters in the Velenje Basin, Slovenia
Tjaa Kandu,Sergej Jamnikar,Jennifer McIntosh
Geologija , 2010,
Abstract: The geochemical and isotopic composition of surface water and groundwaters in the Velenje Basin, Slovenia,were investigated to gain a better understanding of the origin of surface and groundwaters. Surface waters andgroundwaters from the Triassic aquifer are dominated by HCO3-, Ca2+, and Mg2+ from dissolution of carbonate minerals,while groundwaters from the Pliocene and Lithotamnium aquifers have distinct geochemical signatures,enriched in Na+ and K+. Surface waters are controlled by calcite dissolution, while groundwaters from the Triassicaquifer are controlled by dolomite dissolution. The partial pressure of CO2 in surface waters and groundwaters iswell above atmospheric concentrations, indicating that these waters are a potential source of CO2 to the atmosphere.The δ13CDIC values of surface waters are shown to be controlled by biogeochemical processes in the terrestrial environment,such as dissolution of carbonates, degradation of organic matter, and exchange with atmospheric CO2,which is more pronounced in the lake waters. The δ13CDIC values of groundwater from the Triassic aquifer are consistentwith degradation of CO2 and dissolution of dolomite. Groundwaters from the Pliocene and Lithotamniumaquifers have δ13CDIC values suggestive of biogenic CO2 reduction and degradation of organic matter.
Isotopic characteristics of shells Mytilus galloprovincialis from eastern coastal area of Adriatic Sea
Tjaa Kandu,Davorin Medakovi?,Tadej Dolenec
Geologija , 2006,
Abstract: Samples of Mytilus galloprovincialis were collected from entire Eastern Adriatic coast to determine δ18O and δ13C performed on calcite and aragonite shell layers. The aim of this work was to check whether shells of M. galloprovincialis are good environmental indicators (water temperature, salinity). Based on measured isotopic composition of oxygen in shell layers and assumed isotopic composition in water temperatures of calcite and aragonite of shell layers were calculated. The calculated temperatures for M. galloprovincialis shell growth of calcite and aragonite shell layer are in good agreement with measured temperatures of sea water. According to our results of δ18O and δ13C in shell layers we canseparate the locations of the investigated area into three groups: those with more influence of fresh water, those with less influence of fresh water and those of marine environments.
Stable isotope geochemistry of different lithotypes of the Velenje lignite (Slovenia)
Tjaa Kandu,Milo? Marki?,Jo?e Pezdi?
Geologija , 2005,
Abstract: The stable isotope composition of carbon and nitrogen in low-rank coals is often used as a supplementary method to assess coal-forming processes in different paleoenvironments. In this study, carbon and nitrogen isotopes were investigated in different macroscopicvarieties i.e. lithotypes, of the Velenje lignite. δ13C and δ15N values were determined in 47 samples. The quantity and petrographical variability of the samples is considerably higher than in previous studies. δ15N characterization of the Velenje lignite is presentedin this paper for the first time. It was found that δ13C and δ15N values of different lignite lithotypes were influenced by original isotopic heterogeneity of the source plant ingredients,and by biogeochemical processes (gelification, mineralization of organic matter) at the early stage of biomass accumulation and its early diagenesis.
A Study of Dog Coprolite from Late Neolithic Pile-Dwelling Site in Slovenia  [PDF]
Tjaa Tolar, Alfred Galik
Archaeological Discovery (AD) , 2019, DOI: 10.4236/ad.2019.71002
Abstract: More than 5000 years old dog’s coprolite was found during rescue excavation at Črnelnik pile-dwelling site in Slovenia. Although human and dog diets may overlap considerably, the content of the consumed and digested food, consisting of plant and/or animal remains biologically diverse. While the investigated fossil excrement contained many fish head bones, scales and teeth of Cyprinidae family, we believe that we are dealing with an individual that had only eaten fish heads, that is why it was suggested to be of dog. Beside the origin and the daily diet of the individual together with the nutritional habits of the dog in the Late Neolithic, the analyses of coprolite provide more important information, for example: the time of year of the deposit, the environmental conditions there, the size and the health of the animal as well as care (or the status) of domesticated animal for humans. The discovery confirms again that animal dung should be an important part of archaeological investigations, specially at waterlogged sites.
A comparison of time characteristics in ball catching between children with and without Down's syndrome [Srovnání asovych charakteristik p i chytání mí e u dětí s Downovym syndromem a bez Downova syndromu]
Tjaa Filip?i?
Acta Universitatis Palackianae Olomucensis : Gymnica , 2010,
Abstract: BACKGROUND: The one handed catching of a ball is a complex coordination ability. It requires the spatial and time adjustment of the hand according to the speed of the approaching ball. OBJECTIVE: Two main objectives were exposed in the course of the present research; namely whether and why children with Down's syndrome (DS) have problems with one handed ball catching compared to the children with no impairment in motor task such as the one handed catching of a ball. METHODS: Eleven children with DS, aged 8, and 16 with no impairment, also aged 8, were required to catch 45 balls (small, medium, and large). No spatial uncertainty regarding the trajectory of the ball was present and therefore only time judgements were required to catch the ball. RESULTS: The results of the present research showed that children with DS missed more balls than the children from the control group; the children with DS missed 30% of the balls vs. the children from the control group, who missed 7% of the balls. In addition, children with DS missed more small balls. The kinematic analysis of the time characteristics of one handed catching revealed that the difference in timing occurs at the time of grasping the ball. When examining the time of the catch in relationship to the time window, it can be seen that most children with DS tended to finish their catch too late. CONCLUSIONS: Since differences were not found for the time of initiation and the time of maximal aperture, the present experiment suggests that it is not so much the anticipatory control but a slowness of movement that causes the higher percentage of catching failures in the children with DS. [VYCHODISKA: Chytání mí e jednou rukou je dovednost s obtí nou koordinací. Vy aduje prostorové a asové p izp sobení pohybu ruky vzhledem k rychlosti p ilétajícího mí e. CíLE: Tento vyzkum měl dva hlavní cíle; toti zjistit, zda a pro mají děti s Downovym syndromem (DS) problémy s chytáním mí e jednou rukou ve srovnání s dětmi, je nemají oslabené motorické dovednosti, nap íklad chytání mí e jednou rukou. METODIKA: Jedenáct dětí s DS, ve věku 8 let, a estnáct bez poruchy motoriky, také ve věku 8 let, mělo za úkol chytit 45 mí (malych, st edních a velkych). Hody byly stabilní, pokud jde o trajektorii mí e, a proto k chycení mí e byl pot eba pouze asovy odhad. VYSLEDKY: Vysledky tohoto vyzkumu ukazují, e děti s DS chytily méně mí ne děti z kontrolní skupiny; děti s DS nechytily 30 % mí , zatímco děti z kontrolní skupiny nechytily 7 % mí . Navíc děti s DS nechytily více malych mí . Kinematická analyza asovych charakte
Vpliv kakovosti vladanja na gospodarsko rast = The Impact of Governance Quality on Economic Growth
Tjaa Redek,Uro? Godnov
Management , 2007,
Abstract: The rise and decline of nations throughout history continuously puzzles economists. Experience shows that successful economic performance is a very complex process, the scope of which goes well beyond the simplified neoclassical approach to growth. Business environment is a key determinant of successful performance of firms. Firms can not grow, will not invest, employ, buy new technology, and develop new technology unless the business environment is good. It consists of numerous aspects of the institutional environment in an economy: the rule of law, property rights protection, capital and financial market development, labor market institutions, international relations, the role of the state, presence of corruption etc. The key institution that often manages – or at least influences – the development of all other institutions is the state. Therefore, an efficient state is crucial for successful economic performance.
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