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3772. Evropský den žen - 8. března 2005
- Creator:
- Uhde, Zuzana
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3773. Exact analytical solutions for contaminant transport in rivers. 1.. The equilibrium advection-dispersion equation
- Creator:
- van Genuchten, Martinus Th., Leij, Feike J., Skaggs, Todd H., Toride, Nobuo, Bradford, Scott A., and Pontedeiro, Elizabeth M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- contaminant transport, analytical solutions, surface water, and advection-dispersion equation
- Language:
- Slovak
- Description:
- Analytical solutions of the advection-dispersion equation and related models are indispensable for predicting or analyzing contaminant transport processes in streams and rivers, as well as in other surface water bodies. Many useful analytical solutions originated in disciplines other than surface-water hydrology, are scattered across the literature, and not always well known. In this two-part series we provide a discussion of the advection-dispersion equation and related models for predicting concentration distributions as a function of time and distance, and compile in one place a large number of analytical solutions. In the current part 1 we present a series of one- and multi-dimensional solutions of the standard equilibrium advection-dispersion equation with and without terms accounting for zero-order production and first-order decay. The solutions may prove useful for simplified analyses of contaminant transport in surface water, and for mathematical verification of more comprehensive numerical transport models. Part 2 provides solutions for advective-dispersive transport with mass exchange into dead zones, diffusion in hyporheic zones, and consecutive decay chain reactions.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3774. Exact analytical solutions for contaminant transport in rivers. 2.. Transient storage and decay chain solutions
- Creator:
- van Genuchten, Martinus Th., Leij, Feike J., Skaggs, Todd H., Toride, Nobuo, Bradford, Scott A., and Pontedeiro, Elizabeth M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- contaminant transport, analytical solutions, surface water, transient storage models, and solute decay chains
- Language:
- Slovak
- Description:
- Contaminant transport processes in streams, rivers, and other surface water bodies can be analyzed or predicted using the advection-dispersion equation and related transport models. In part 1 of this two-part series we presented a large number of one- and multi-dimensional analytical solutions of the standard equilibrium advection-dispersion equation (ADE) with and without terms accounting for zero-order production and first-order decay. The solutions are extended in the current part 2 to advective-dispersive transport with simultaneous first-order mass exchange between the stream or river and zones with dead water (transient storage models), and to problems involving longitudinal advectivedispersive transport with simultaneous diffusion in fluvial sediments or near-stream subsurface regions comprising a hyporheic zone. Part 2 also provides solutions for one-dimensional advective-dispersive transport of contaminants subject to consecutive decay chain reactions.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3775. Exact linearization of nonholonomic system dynamics applied to control of differentially driven soccer robot
- Creator:
- Grepl, Robert, Lee, Byoungsoo, Kratochvíl, Ctirad, Šolc, František, and Hrabec, Jakub
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- nonholonomic system dynamics, exact linearization, and soccer robot
- Language:
- English
- Description:
- This paper describes the dynamic modeling of nonholonomic system for control purposes. The equations of motion together with nonholonomic constraint are reduced into system of five 1st order equations. Further, the exact linearization is performed and finally we obtain a decoupled system of two independent integrator chains. Next we describe the controller design, and at the end, the simualtion results are presented. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3776. Examination of aerial diatom flushing across watersheds in Luxembourg, Oregon and Slovakia for tracing episodic hydrological connectivity
- Creator:
- Pfister, Laurent, Wetzel, Carlos E., Martínez-Carreras, Núria, Iffly, Jean François, Klaus, Julian, Holko, Ladislav, and McDonnell, Jeffrey J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- aerial diatoms, hillslope-riparian zone-stream continuum, and hydrological connectivity
- Language:
- Slovak
- Description:
- Hydrological processes research remains a field that is severely measurement limited. While conventional tracers (geochemicals, isotopes) have brought extremely valuable insights into water source and flowpaths, they nonetheless have limitations that clearly constrain their range of application. Integrating hydrology and ecology in catchment science has been repeatedly advocated as offering potential for interdisciplinary studies that are eventually to provide a holistic view of catchment functioning. In this context, aerial diatoms have been shown to have the potential for detecting of the onset/cessation of rapid water flowpaths within the hillslope-riparian zone-stream continuum. However, many open questions prevail as to aerial diatom reservoir size, depletion and recovery, as well as to their mobilisation and transport processes. Moreover, aerial diatoms remain poorly known compared to freshwater species and new species are still being discovered. Here, we ask whether aerial diatom flushing can be observed in three catchments with contrasting physiographic characteristics in Luxembourg, Oregon (USA) and Slovakia. This is a prerequisite for qualifying aerial diatoms as a robust indicator of the onset/cessation of rapid water flowpaths across a wider range of physiographical contexts. One species in particular, (Hantzschia amphioxys (Ehr.) Grunow), was found to be common to the three investigated catchments. Aerial diatom species were flushed, in different relative proportions, to the river network during rainfall-runoff events in all three catchments. Our take-away message from this preliminary examination is that aerial diatoms appear to have a potential for tracing episodic hydrological connectivity through a wider range of physiographic contexts and therefore serve as a complementary tool to conventional hydrological tracers.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3777. Examples of rotational component records of mining induced seismic events from the Karviná region
- Creator:
- Zdeněk Kaláb and Jaromír Knejzlík
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, seizmicita, seismicity, rotational component, rotational seismometer, mining induced seismicity, 7, and 551
- Language:
- English
- Description:
- Russian electrodynamic seismometer named S-5-S is adaptable for measurement of rotational ground motion. In this paper brief information about mentioned adaptation is presented. Initial results from experimental m easurement in Karviná region in 2011 with high mining induced seismicity are documented. Measured values for the horizontal component reached up to 1 mrad s-1 , while the seismic energy of these events did not exceed the value of 10 5 J and hypocentral distances were within 2 km., Zdeněk Kaláb and Jaromír Knejzlík., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3778. Excelence ve vědě
- Format:
- print, text, regular print, bez média, and svazek
- Type:
- article, zprávy, reports, model:article, and TEXT
- Subject:
- Věda. Všeobecnosti. Základy vědy a kultury. Vědecká práce, věda a politika, věda a společnost, výzkum a vývoj, science and politics, science and society, research and development, 12, and 00
- Language:
- Czech
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3779. Exceptional photosynthetic performance of Capparis spinosa L. under adverse conditions of Mediterranean summer
- Creator:
- Levizou, E., Drilias, P., and Kyparissis, A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll fluorescence, daily and seasonal photosynthesis;, net photosynthetic rate, stomatal conductance, summer perennial, transpiration rate, and water potential
- Language:
- Multiple languages
- Description:
- Diurnal and seasonal fluctuations in water potential (Ψ), stomatal conductance (gs), transpiration rate (E), and net photosynthetic rate (PN) were monitored in Capparis spinosa L., a Mediterranean plant growing during summer, i.e. at the period considered the most stressful for local plant life. In spite of the complete absence of rain, Ψ exhibited a modest drop at midday (-2.7 MPa), but was fully recovered overnight, indicating sufficient access to water sources. The stomata remained open throughout the day and season and the high E resulted in leaf temperatures up to 3.9 °C below air temperature. Additionally, PN of the fully exposed leaves was higher than 25 μmol m-2 s-1 for more than 10 h per day throughout the summer growth period. No symptoms of photooxidative stress were shown, as judged by maximum photosystem 2 photochemical efficiency (Fv/Fm) and the function of xanthophyll cycle. Indeed, diurnal inter-conversions of the xanthophyll cycle components were modest during the summer and a more intensive function of the cycle was only evident during leaf senescence in autumn. In comparison with a semi-deciduous and an evergreen sclerophyll co-existing in the same ecosystem, C. spinosa assimilated up to 3.4 times more CO2 per m2 during its growth period (May to October) and up to 1.8 times more on an annual basis. and E. Levizou, P. Drilias, A. Kyparissis.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
3780. Excess irradiance causes early symptoms of senescence during leaf expansion in photoautotrophically in vitro grown tobacco plants
- Creator:
- Radochová, B. and Tichá, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- chlorophyll a fluorescence, leaf area, leaf dry mass, leaf ontogeny, net oxygen evolution rate, Nicotiana, and photosynthesis
- Language:
- Multiple languages
- Description:
- Photosynthetic parameters, growth, and pigment contents were determined during expansion of the fourth leaf of in vitro photoautotrophically cultured Nicotiana tabacum L. plants at three irradiances [photosynthetically active radiation (400-700 nm): low, LI 60 µmol m-2 s-1; middle, MI 180 µmol m-2 s-1; and high, HI 270 µmol m-2 s-1]. During leaf expansion, several symptoms usually accompanying leaf senescence appeared very early in HI and then in MI plants. Symptoms of senescence in developing leaves were: decreasing chlorophyll (Chl) a+b content and Chl a/b ratio, decreasing both maximum (FV/FM) and actual (ΦPS2) photochemical efficiency of photosystem 2, and increasing non-photochemical quenching. Nevertheless, net photosynthetic oxygen evolution rate (PN) did not decrease consistently with decrease in Chl content, but exhibited a typical ontogenetic course with gradual increase. PN reached its maximum before full leaf expansion and then tended to decline. Thus excess irradiance during in vitro cultivation did not cause early start of leaf senescence, but impaired photosynthetic performance and Chl content in leaves and changed their typical ontogenetic course. and B. Radochová, I. Tichá.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public