Optimization methods are used to estimate parameters required for routing floods through open compound channels. Besides initial and boundary flow conditions, data required especially include, crosssectional area (A) of flow and conveyance (K) as functions of flow depth (y) for a representative crosssection of the study reach. Thus, instead of optimizing upon channel's geometric and hydraulic parameters, optimization is performed upon non-physical parameters in assumed A(y) and K(y) relationships. The optimization method selected for this application is the Nelder and Mead Simplex Algorithm. The objective function is expressed in terms of the relative differences between observed and simulated stages and discharges, which are evaluated based on the complete numerical solution of St Venant equations. This approach to formulating the optimization problem was applied to unsteady flow data sets for an experimental reach of the River Main in Northern Ireland. Based on statistical analysis, simulated and observed stages were found to be in good agreement. and Parametre potrebné pre kvantifikáciu transformácie povodňových vĺn v otvorených, zložených kanáloch, boli určené optimalizačnou metódou. Okrem počiatočných a okrajových podmienok sú potrebné ďalšie údaje, vrátane plochy priečneho rezu prúdom (A), ako aj vodivosť časti toku (K) ako funkcie hĺbky (y) pre reprezentatívny priečny rez. Namiesto optimalizácie geometrických a hydraulických parametrov kanála, optimalizácia sa vykonala pre nefyzické parametre, predpokladajúc závislosti A(y) a K(y). Vybranou metódou optimalizácie je Nelderov a Meadov Simplex Algoritmus. Funkcia je vyjadrená pomocou relatívnych rozdielov medzi pozorovanými a simulovanými vodnými stavmi a prietokmi, ktoré boli vyčíslené numerickým riešením rovníc St. Venanta. Tento spôsob formulácie optimalizačného problému bol aplikovaný na údaje pre neustálené prúdenie v experimentálnom priamom úseku rieky Main (River Main) v Severnom Írsku. Štatistickou analýzou bolo zistené, že simulované a merané vodné stavy boli veľmi blízke.
The aim of the paper is to study spatial and temporal changes in the magnitude, duration and frequency of high flows in the Danube basin. A hydrological series of the mean daily discharges from 20 gauging stations (operated minimally since 1930) were used for the analysis of changes in the daily discharges. The high flow events were classified into three classes: high flow pulses, small floods, and large floods. For each year and for each class, the means of the peak discharges, the number and duration of events, and the rate of changes of the rising and falling limbs of the waves were determined. The long-term trends of the annual time series obtained were analyzed and statistically evaluated. The long-term high flow changes were found to be different in three individual high flow classes. The duration of the category of high flow pulses is decreasing at 19 stations on the Danube and is statistically significant at the Linz, Vienna, Bratislava and Orsova stations. The frequency of the high flow pulses is increasing in all 20 stations. Also, the rising and falling rates of the high flow pulse category are increasing at the majority of the stations. The long-term trends of the selected characteristics of the small floods are very similar to the trends of the high flow pulses, i.e., the duration of small floods is decreasing, and their mean number per year is increasing. In the category of large floods the changes were not proved.
The fact that flash floods initiated in arable catchments are often accompanied by massive sediment and nutrient loads often leads to the assumption that surface runoff is the principle pathway by which runoff reaches watercourses. On the basis of an evaluation of several rainfall-runoff events in a representative agricultural catchment, we show that runoff from cultivated land may be generated in a way similar to that seen on forested slopes, where shallow subsurface runoff is the predominant pathway by which runoff makes its way to watercourses in most runoff events. To identify the predominant runoff pathway, we employed a combination of turbidity measurements and stream discharge data. Suspended sediment flux, a newly introduced index representing the ratio between precipitation duration and total sediment yield, and direction of the discharge-turbidity hysteresis loops were proposed as reflective indicators of the frequency of runoff via different pathways. In our study, most of the events initiated by rainstorms of various intensities and durations resulted in rapid increases in stream discharge. Although we observed temporal variability of topsoil properties attributable to seasonal weather changes and agricultural activities, e.g. bulk density and porosity, runoff generation was mainly driven by precipitation characteristics and the initial catchment saturation.
In recent years the issue of the natural hydrological and meteorological time series fluctuation has been discussed more and more intensively. As the series of measured hydrological and climatological data become longer and easier worldwide accessible it is possible to deal with a large amount of historical data in their complexity. Handling these data we cannot go without new methods of mathematical statistics and mathematical analysis. In the study some methods of the long-term trends identification in the hydrological time series are presented. Apart from the classical methods, like that of moving averages, the paper focuses in detail on the Hodrick-Prescott (HP) filter. The HP filter is applicable to the trend analysis of the long-term hydrological time series. Next, a new method of the period length identification, the combined periodogramm method, is theoretically developed. Using this method the long cycles length identification becomes more precise. Here, the cycle is considered to be long when it takes the length of about 1/6 to 1/3 of the measured time series. Identification of such long cycles is important with respect to the future hydrospherical processes forecast. Results of application of these methods to the Slovak hydrological time series are presented in the second part of the study. and V posledných rokoch sa začína čoraz viac diskutovať na tému prirodzených fluktuácií hydrologických a meteorologických radov. So stále sa predlžujúcimi radmi meraných hydrologických a klimatických údajov a zlepšujúcim sa prístupom k meraným údajom na celom svete možno komplexnejšie spracovať veľký počet historicky nameraných časových radov. Pri spracovávaní týchto údajov sa nezaobídeme bez rozvoja nových metód štatistiky a matematickej analýzy. V predloženej štúdii boli opísané metódy identifikácie dlhodobého trendu hydrologických radov. Popri už klasických metódach (metóde kĺzavých priemerov) bol v tejto práci rozpracovaný Hodrickov-Prescottov (HP) filter. HP filter možno aplikovať na analýzu trendu dlhodobých ročných hydrologických časových radov. Ďalej bola v štúdii teoreticky rozpracovaná nová metóda identifikácie dĺžky periód časových radov - metóda kombinovaného periodogramu. Uvedená metóda spresňuje identifikáciu dĺžky dlhých cyklov, teda cyklov s dĺžkou okolo 1/6 až 1/3 meraného časového radu. Práve identifikácia týchto dlhých cyklov je veľmi dôležitá pri odhade budúceho vývoja hydrosféry. Praktické použitie uvedených metód na slovenských hydrologických radoch je prezentované v druhej časti štúdie.
In the second part of the paper long-term trends and cyclicity in hydrological time series are identified using both the Hodrick-Presoctt (HP) filter and the combined periodogram. The HP filter seems to be a good tool for analyzing annual time series. It clearly identifies the decrease in the Slovak rainfall time series 1900-1990 and the increase in those of 1990-2000. Using the combined periodogram method oscillation cycles in the discharge time series of main Slovak rivers were identified. These cycles are likely to be characteristic for all Slovak rivers in general. This means the discharge time series are not stationary, they involve a cyclical component. To calculate hydrological characteristics it is necessary to have such a sufficiently long time series that involves both complete wet and dry periods. Because of existence of an about 29 year cycle, a period consisting of 30 years is very suitable. From the long-term point of view, both Danube and Morava Rivers possess steady trends while in the Bodrog and Vah rivers a decrease in discharge occurred during the XX Century. This decrease was mainly due to lower annual rainfalls in Slovakia. When determine long-term discharges, an oscillation of wet and dry periods should be taken into account. The trends should be determined for closed cycles, i.e., either from minimum to minimum or from maximum to maximum. From the long-term trends analysis it follows that the linear trend is not adequate to extrapolate the hydrological time series to the future. and V druhej časti štúdie je identifikovaný dlhodobý trend a cyklickosť slovenských hydrologických časových radov použitím Hodrickovho-Prescottovho (HP) filtra a metódou kombinovaného periodogramu. HP filter sa ukázal byť dobrým nástrojom na analýzu časových radov ročných údajov. Zreteľne identifikuje pokles zrážkových úhrnov na územie SR v období 1900-1990 a nárast úhrnov v rokoch 1990-2000. Metódou kombinovaného periodogramu boli identifikované cykly kolísania prietokových radov najvýznamnejších slovenských tokov. Je pravdepodobné, že tieto cykly sú charakteristické pre všetky slovenské toky. Prietokové rady zahŕňajú v sebe cyklickú zložku. Pri výpočtoch hydrologických charakteristík je potrebné hydrologické charakteristiky počítať z dostatočne dlhých radov zachytávajúcich celý cyklus - mokré i suché obdobie. Tridsaťročné obdobie na výpočet hydrologických charakteristík tokov je vzhľadom na existenciu ca 29-ročného cyklu veľmi vhodné. Z dlhodobého hľadiska Dunaj a Morava majú vyrovnaný trend vodnosti, v Bodrogu a vo Váhu došlo v 20. storočí k poklesu odtoku. Na tomto poklese majú najväčší podiel nižšie ročné zrážkové úhrny na územie SR. Pri určovaní dlhodobých trendov prietokov je potrebné brať do úvahy cykly striedania sa suchých a mokrých období. Vývojové trendy je potrebné určovať za obdobia uzavretých cyklov - od minima po minimum, alebo od maxima po maximum. Z analýzy dlhodobých trendov vyplýva, že použitie lineárneho trendu nie je vhodné na extrapoláciu hydrologických radov do budúcnosti.
The paper presents relationship between the Standardised Precipitation Index (SPI) and physiological responses of individual trees in a beech stand using an example of an experimental plot in Bienska valley (Zvolen, Slovakia). SPI is a widely used tool for monitoring both short-term and long-term droughts, and for the assessments of drought impacts on agriculture. Due to the complex ecosystem bonds, monitoring of drought in forests often requires a sophisticated technological approach. The aim of the paper was to correlate the SPI on the physiological responses of trees that were recorded during the performed physiological research (sap flow, and stem circumference increment) at the site in the growing seasons (May to September) of the years 2012-2014. The results revealed a relationship between the index and the physiological responses, although the problem with the impact of other environmental factors has also come up. The secondary correlation, in which soil water potential that significantly affects physiological responses of forest tree species was used as a dependent variable, showed a tighter relationship with the SPI. We found the highest correlation between the soil water potential and the values of SPI aggregated for five weeks. This indicates that the beech forest has a five week resistance to drought stress. The results also enable simple monitoring of the initiation of the drought stress by applying SPI for five weeks.
In the realm of the philosophy of sounds and auditory experience there is an ongoing discussion concerned with the nature of sounds. One of the contestant views within this ontology of sound is that of the Property View, which holds that sounds are properties of the sounding objects. A way of developing this view is through the idea of dispositionalism, namely, by sustaining the theory according to which sounds are dispositional properties (Pasnau 1999; Kulvicki 2008; Roberts 2017). That portrayal, however, is not sufficient, as it has not inquired the metaphysical debates about dispositions beyond the conditional analysis. In this paper, I try to advance this view by including recent developments (for instance Bird 2007; Vetter 2015) in the field of dispositionalism and I analyse whether this new version can sort out known and new objections to Property View.
The debates over the problem of faultless disagreement have played a major role in shaping the landscape of today’s semantic theories. In my paper, I argue that even though the existent contextualism-friendly proposals explain a lot of disagreement data by specifying various ways in which speakers may use subjective predicates, neither provides a satisfactory account which would explain what all the subjective disagreements have in common. In particular, what is lacking is an explanation of the persistent autocentric cases (Lasersohn 2004), i.e., disagreements in which each speaker utters a subjective sentence while openly and knowingly occupying his or her own perspective. In my paper, I offer a solution which consists in supplementing the standard contextualist semantics with an explanation of this most problematic class of cases, which is possible due to redescribing the phenomena in speech act nomenclature.
Results of cadmium sorption and desorption, as well as distribution coefficients of cadmium in the soils from the Danubian Lowland and from Veľký Ďur (neighbourhood of the nuclear power plant Jaslovske Bohunice) are presented in this study. It was found that Cd adsorption is high in studied soils already after the one-minute lasting Cd-soil contact. The results obtained show that the highest sorption of cadmium is in the loamy-sand soil from Kalinkovo (99.75 %). Zeolite application was the most effective in the loam soil from Macov. Sorption of cadmium in this soil increased by 1.45%. The presence of zeolite in chosen soil samples influenced Cd desorption, too. In loamy-sand soil from Kalinkovo cadmium desorption decreased by 50 % after zeolite application. Sorption experiments with radionuclides (85Sr and 137Cs) were conducted on brown earth from the site Velľký Ďur. The 137Cs sorption is very high in studied soil. Zeolite is more effective in the case of 85Sr. Desorption of radiostrontium decreased by 50% after zeolite application. and V práci sa prezentujú výsledky sorpcie, desorpcie a hodnoty rozdeľovacieho koeficientu kadmia vo vybraných vzorkách pôd Podunajskej nížiny a hnedozeme z lokality Veľký Ďur. Kadmium je silne sorbované sledovanými pôdami už po 1 minúte trvania kontaktu. Najvyššia sorpcia sa pozorovala u hlinito-piesočnatej pôdy z lokality Kalinkovo, kde pomerné adsorbované množstvo S kadmia bolo 99,75 %. Aplikácia zeolitu sa najviac prejavila u hlinitej pôdy z Macova, kde sa pomerné adsorbované množstvo S kadmia zvýšilo o 1,45 %. Zeolit ovplyvnil aj desorpciu naviazaného kadmia v sledovaných pôdnych vzorkách. Najviac kadmia sa desorbovalo z hlinito-piesočnatej pôdy z Kalinkova a aplikácia zeolitu znížila pomerné desorbované množstvo kadmia na menej ako polovicu. Sorpčné experimenty s rádionuklidmi (85Sr a 137Cs) boli vykonané na hnedozemi z lokality Veľký Ďur. 137Cs je už samotnou pôdou sorbované takmer na 100 % a prítomnosť zeolitu už sorpciu prakticky nezvyšuje. Zeolit zvyšuje sorpciu hlavne u rádiostroncia. Desorpcia stroncia po aplikácii zeolitu sa znížila o 50 %.