Hydrogeological and speleological research of the spring cave Slatinski Izvor and its recharge are (Republic of Macedonia)Biljana Gichevski
Opis: This thesis represents a comprehensive study, giving first extensive information on the hydrogeological and speleological characteristics of the spring cave Slatinski Izvor and its catchment area. The researched spring is located in the Poreče basin of West-Central Macedonia, in the river valley of Slatinska Reka. The wider area around the spring belongs to two tectonic units. The Slatinski Izvor spring is situated on the Pelagonian horst anticlinorium, which is composed of carbonate rocks. The second is the Western Macedonian zone, and it is composed of non-carbonate rocks. The spring represents a significant potential for water supply for the settlement Slatina. Prior to this research only some basic information about the karst aquifer in Precambrian dolomite marbles was available. Therefore, my goal was to ensure better understanding of the functioning of the karst system in the recharge area of the spring, assessment of its vulnerability to various pollution sources, as well as study of karst development of the area.
Because karst aquifers have unique hydrogeological characteristics and specific nature, they also require specifically adapted investigation methods. In order to reach the main goal, speleological investigations, hydrological methods, hydrochemical methods and tracer test were used. A monitoring network was combined with regular samplings for major and trace elements analysis, which enabled considerable advances in understanding the functioning of the karst system. The data from two-year period (December 2011 – November 2013) was compared and analyzed.
The controlling of the karst development in the study area mostly depends on the tectonic and geologic conditions. Incision of Slatinska Reka is the main controlling factor in cave development by lowering the base level of karst terrains. All investigated caves (Gorna Slatinska, Slatinska II, Ovčarska Peštera, Puralo, Slatinski Izvor) have “normal” epigenic karst development. Slatinski Izvor is the youngest cave. The Slatinski Izvor spring serves as a cave entrance for the same cave and, represents the outflow of groundwater from the karst system.
A conceptual model of the karst system of the study area was developed. The Slatinski Izvor spring has typical karst hydrological regime. The karst system is well developed by conduits and rains infiltrated into vadose zone flow rapidly towards the spring. The travel time of low mineralized water within the system corresponds well with the results from an artificial tracer test. Performed artificial tracer test confirmed that the Slatinski Izvor spring is recharged by allogenic stream. The dominant apparent flow velocity of 250 m/h, a single peak of the tracer breakthrough curve and more than 87% of tracer recovered indicate a rapid conduit flow and high vulnerability of the observed drinking water source. Analysis of spatial and temporal variations of physical and chemical parameters show that waters in the study area had different origin and were transmitted along different flow paths. The origin of the water of the Slatinski Izvor spring is from non-carbonate area, but the influence of mixed limestone-dolomite sequence in the carbonate area is significant. The results point out to short residence time of the water in the karst aquifer.
The anthropogenic impact in the study area is insignificant which is reflected in the good water quality. In order to preserve it, land surface zoning was performed in terms of groundwater and spring water vulnerability to pollution according to the hydrogeological research.
A comprehensive research with a combined use of various research tools presents an innovative approach and a new contribution to the Macedonian karstological science. Applied methods proved to be successful for to study of the karst system. Finally, the results of the study have clear applicative significance in terms of drinking water management.
Ključne besede: karst hydrology, cave, speleological investigation, hydrochemistry, tracer test, spring Slatinski Izvor
Objavljeno: 14.10.2016; Ogledov: 9322; Prenosov: 59
Ogledov v mesecu: 1010
Vpliv metformina in sorodnih ksenobiotikov na viabilnost celic raka dojkeSara Klemenčič
Opis: Farmacevtska industrija se danes med drugim sooča tudi z negativnimi vplivi svojih proizvodov na okolje. Tak primer je metformin, ki spada med najpogosteje predpisana zdravila v procesih zdravljenja diabetesa tipa II in je hkrati v fazi kliničnih raziskav kot zdravilo za zdravljenje rakavih obolenj. Deluje tako, da zavira celično dihanje, niža proizvodnjo ATP in aktivira z AMP-aktivirano protein kinazo (AMPK), ki je glavni metabolični senzor v evkariontskih celicah. V diplomskem delu smo želeli ugotoviti, ali metformin in sorodni ksenobiotiki, povezani z delovanjem AMPK (spojina C in bromokrotonska kislina), vplivajo na rast visoko invazivnih celic adenokarcinoma dojke MDA-MB-231. To smo storili s pomočjo spektrofluorimetričnega testa viabilnosti z barvilom Presto Blue, ki temelji na sposobnosti zdravih celic, da reducirajo barvilo po vstopu v celico. Pokazali smo, da obstaja linearna zveza med številom celic MDA-MB-231 v populaciji in fluorescenčnim signalom barvila, kar potrjuje ustreznost izbrane metode. Celice smo gojili 48 h pri optimalnih pogojih in v prisotnosti različnih koncentracij vsake od treh učinkovin. Pokazali smo, da viabilnost celic pojema z naraščanjem koncentracije učinkovine. Rezultati kažejo, da inhibicija kataboličnih in oksidativnih procesov v celici (mitohondrijsko dihanje, oksidacija maščobnih kislin in aktivacija AMPK) negativno vpliva na rast in preživetje celic MDA-MB-231. Z našimi rezultati smo prispevali k boljšemu razumevanju mehanizma delovanja metformina in sorodnih zdravilnih učinkovin usmerjenih proti kataboličnemu metabolizmu.
Ključne besede: viabilnost, metformin, bromokrotonska kislina, spojina C, dorzomorfin, AMPK, rak dojke, MDA-MB-231
Objavljeno: 31.01.2017; Ogledov: 3748; Prenosov: 149
Ogledov v mesecu: 1005
Visible-light photoactivity of Bi-pyrochlores with high Fe contentsMatjaž Valant
, Metka Benčina
, Mattia Fanetti
Ključne besede: fotoaktivnost, fotokataliza, katalizatorji, kemijska kinetika, materiali, piroklorna struktura, rekombinacija, železove spojine
Objavljeno: 30.12.2015; Ogledov: 7998; Prenosov: 92
Ogledov v mesecu: 978
On the Optionality of Wh-Fronting in a Multiple Wh-Fronting LanguagePetra Mišmaš
Opis: This thesis explores the fact that in Slovenian multiple wh-questions not all wh-phrases have to front. This suggests that multiple wh-movement in Slovenian is optional. The majority of the existing literature on multiple wh-fronting focuses on questions in which all wh-phrases have to move to clause initial positions, I, on the other hand, focus on optionality in multiple wh-questions. I show movement in Slovenian is not avoided because of phonological, syntactic or semantic restrictions that influence other languages (cf. Bošković 2002), and that the Principle of Distinctness (Richards 2010) does not account for all cases of optional multiple wh-fronting in Slovenian.
Three types of multiple wh-questions in Slovenian are determined and analyzed: (i) questions in which all wh-phrases move to clause initial positions (i.e. questions with multiple wh-fronting), (ii) questions in which one wh-phrase has to be moved to a clause initial position and the rest undergo movement to a clause internal position (multiple wh-questions with short movement), (iii) questions in which at least one wh-phrase has to be moved to a clause initial position and the rest stay in situ (multiple wh-questions with wh-in-situ). Crucially, in all three types at least one wh-phrase has to move to a clause initial position for a question to receive a true question reading.
I assume the Cartographic approach and propose an account of multiple wh-fronting in Slovenian in which one wh-phrase has to move to an Interrogative Projection (the clause initial position) in the Left Periphery while the remaining wh-phrases move to Wh-Projections in the Left Periphery, questions in (i), or the Low Periphery, questions in (ii). I propose that wh-phrases with a wh-feature undergo wh-movement, which means that wh-movement is in fact obligatory in Slovenian. In questions of type (iii), wh-phrases that do not undergo movement are in fact bare wh-pronouns, which one also finds in polarity contexts, that are licensed by the interpretable Q+wh-feature located in the Interrogative Projection. Because the bare wh-pronouns do not come with a wh-feature, they do not have to move. I conclude that wh-movement in Slovenian only appears to be optional.
Ključne besede: multiple wh-fronting, short movement, optionality, Interrogative Projection, Left Periphery, Low Periphery, bare wh-pronouns, wh-in-situ
Objavljeno: 10.11.2015; Ogledov: 3984; Prenosov: 245
Ogledov v mesecu: 177
Thermal Effusivity Investigations of Solid Thermoelectrics Using the Front Photopyroelectric DetectionCarmen Tripon
, Dorin Dadarlat
, Katalin Kovacs
, Victor Petru Tosa
, Mladen Franko
Opis: The front photopyroelectric configuration (FPPE), making use of air as a coupling
fluid between the sample and sensor, was applied to measure the thermal effusivity of
some solid thermoelectric materials. The investigated samples were ZnO, CuCrO2,
and two samples of high manganese silicide (HMS) thermoelectric
materials. Most of these materials are porous and consequently, the classical PPE
method, making use of standard coupling fluids between sensor and sample, cannot
be used due to the fact that the coupling fluid penetrates inside the sample and leads
to incorrect results. With this work we extend (to thermoelectric solids) the area of
application of a method, recently proposed by Salazar et al. (Measurement 121: 96,
2018). Experimentally, the thermal effusivity is obtained from a multi-parametric
fit of the phase of the FPPE signal as a function of the modulation frequency (with
sample’s thermal effusivity, thickness of the sensor-sample air gap and heat losses
by convection and radiation, as fitting parameters). It was demonstrated that, in some
particular cases, the three parameters are independent and consequently, the solution
of the fit is unique. Where possible, the obtained results have been compared with
data from the literature and good agreement was found.
Ključne besede: Front photopyroelectric configuration (FPPE), Solid thermoelectrics, Thermal effusivity
Objavljeno: 02.05.2020; Ogledov: 144; Prenosov: 0
Ogledov v mesecu: 144
Space weather research with the Pierre Auger ObservatoryMiha Živec
Opis: Space weather refers to environmental conditions in the interplanetary space and Earth’s
magnetosphere, ionosphere and exosphere and can influence the performance and reliability
of electronics based technological systems. The major role in space weather
changes plays the solar wind, a stream of charged particles (mostly electrons and protons)
with energies of approximately 1 keV, that can cause geomagnetic storms and auroras.
During their entry into the atmosphere, high energy cosmic rays collide with atomic
nuclei of atmospheric gasses. When scattering occurs extensive air showers are created.
Those cascades of secondary particles create flashes of light due to the Cherenkov
effect as well as excite molecules of nitrogen gas in atmosphere, which then glow in
fluorescent light. In order to observe the light created by air showers, it has to be
collected with telescopes. The particles from the cascades that reach ground can be
detected with surface detectors. The Pierre Auger Observatory is the largest observatory
for cosmic ray measurements. It is located in Argentinian pampas covering an area of
3000 km2. It consists of 1660 surface detectors and 27 fluorescence telescopes. For
cosmic rays with energies above few 1017 eV, a precise reconstruction of energy and
direction of primary particle is achievable. Observatory also allows measurement of
flux of incoming particles down to primary energies in ca. 10 GeV - 10 TeV interval, with a median energy ca. 80-90 GeV. This measurement capability is called "scaler"
mode, since the corresponding data consist of scaler counted cascade particles with
deposited energy between 15 and 100 MeV, at the average rate of 2 kHz per individual
For the purpose of this master thesis I compared the data from scaler mode measurements
with measurements of neutron monitors, which are commonly used for space weather
observations. With the correlation received from the comparison, I showed that scaler
mode operation of Pierre Auger observatory can be used to monitor space weather events
such as solar cycle and the decreases in the observed galactic cosmic ray intensity due
to solar wind (Forbush decrease).
Ključne besede: Pierre Auger Observatory, cosmic rays, space weather, Forbush decrease
Objavljeno: 17.09.2019; Ogledov: 819; Prenosov: 38
Ogledov v mesecu: 143