National Repository of Grey Literature 91 records found  beginprevious77 - 86next  jump to record: Search took 0.00 seconds. 
The effect of fertilization on plant decomposition in two wet grasslands
ŠEBELÍKOVÁ, Lenka
A basic literature review about decomposition processes in general and decomposition on wet ecosystems in particular was provided by this thesis. The aim of the practical part was to determine how increased fertilization changes aboveground decomposition rates of the dominant plant species in two wet grassland sites in the Czech Republic.
Decomposition of aboveground biomass of a herbaceous wetland stand
KLIMOVIČOVÁ, Lucie
This work deals with the decomposition of aboveground vegetation in wetlands. The decomposition process leads to the release of greenhouse gases, which are currently being studied primarily in relation to current climate change. The decomposition rate was established on the flooded part of the Wet Meadows near Třeboň. The intensity of degradation processes was evaluated using the litter-bag method. Bags of dry matter were located in the vicinity of the automatic meteorological station at four randomly selected sites in April 2009. The litter bags were fixed so that their positio followed the natural positionof the standing dead matter. Values of the decomposition rate were assessed for two sampling, summer and autumn 2009. The obtained values of decomposition rates are discussed with the results of Kovářová who used the litter-bags method on Wet Meadows near Třeboň in the past.
Acitivity of phenoloxidases and peroxidases in the litter of spruce forest in Plešné and Čertovo lake watersheds
APPLOVÁ, Markéta
The aim of the study was to determine the activity of phenoloxidases and peroxidases in three dominating litter samples (Vaccinium myrtillus, Calamagrostis villosa and Picea abies) from Plešné and Čertovo lake watersheds. High activity of lignin-degrading enzymes was detected in litter incubated at 0°C. Activity of enzymes was in general higher at 10°C but the difference was not significant compared to 0°C. In Plešné Lake watershed high amount of phenolic compounds negatively influenced the activity of enzymes compared to Čertovo Lake watershed, where the effect of phenolic compounds was opposite. The highest activities of the enzymes were found in the Calamagrostis villosa litter from Plešné Lake watershed and in the litter of spruce needles from Čertovo lake watershed.
System of evaluation of soil organic matter based on fractionation by level of hydrophilic characteristics and by characterisation of fractions with differential thermic analysis
STROSSER, Eduard
The contemporary methods of evaluation of the soil organic matter do not sufficiently characterize its stability. The aim of this study is to develop a method for soil organic matter stability evaluation. The four different methods were tested, two based on chemical principle a two on microbiology principle. The first method is based on sequential soil organic matter fractionation by a system of solvents with increasing polarity, the second method uses oxidizers with different oxidizing efficiency. In the third method micro-organisms decompose soil organic matter in anaerobic environment as well as in the four method, but this one makes use of up gas production measuring sensors. The method of sequential extraction is not suitable for practical use, the oxidation method is preferred. The oxidation method also both microbiology methods imply that the most important part of soil organic matter is decomposed rapidly or while using weak oxidizer. This fraction is the most important for evaluation decomposability and it is characteristic for particular soils. After decomposition of this part of SOM its remnant is decomposed steady and linear or micro-organisms are not able to decompose it.
DECOMPOSITION METHODS FOR A PIV DATA ANALYSIS WITH APPLICATION TO A BOUNDARY LAYER SEPARATION DYNAMICS
Uruba, Václav
Separation of the turbulent boundary layer (BL) on a flat plate under adverse pressure gradient was studied experimentally using Time-Resolved PIV technique. The results of spatio-temporal analysis of flow-field in the separation zone are presented. For this purpose, the POD (Proper Orthogonal Decomposition) and its extension BOD (Bi-Orthogonal Decomposition) techniques are applied as well as dynamical approach based on POPs (Principal Oscillation Patterns) method. The study contributes to understanding mechanisms of a boundary layer separation process. The acquired information could be used to improve strategies of a boundary layer separation control.
Modified Titania Nanolayers for Photodegradation Applications
Krejčíková, Simona ; Šolcová, Olga ; Maléterová, Ywetta ; Cajthaml, Tomáš
This study is focused on preparation and characterisation of the specially designed photoactive materials and their modified versions suitable for photo-processes carried out upon illumination in the visible and UV regions of the light spectrum. Decomposition of a resistant contaminant 4 - chlorophenol was chosen as the representative reaction for our study.
Sphagnum mosses – Ecosystem engineers of bogs
Hájek, Tomáš
I evaluated production and decomposition characteristics of six dominant Sphagnum species in their natural microhabitats distributed along the gradient of water table in an open ombrotrophic bog. The growth in length was much higher in pools and hollows than in hummocks but the resulting annual production was roughly similar between the microhabitats due to a greater shoot and bulk density in hummocks. Although hummocks provided much higher potential for decomposition than hollows, the Sphagnum litter decomposed more slowly in hummocks due to much lower litter quality of the hummock sphagna. Thus the hummock Sphagnum species possess both principal mechanisms participating in maintaining hummocks above hollows – a sufficient production rate and limited decomposition rate. These mechanisms emphasize the role of Sphagnum mosses as autogenic ecosystem engineers controlling also the microhabitat diversification in patterned mires.
Microarthropods and microbial participation in oak and beech litter decomposition
Farská, Jitka ; Jínová, Kristýna ; Jirout, Jiří ; Petrásek, Jiří ; Čápová, Lenka ; Rusek, Josef ; Krištůfek, Václav ; Elhottová, Dana ; Starý, Josef
The aim of our work was to describe the impact of a simulated vegetation zone shift to higher altitudes (i) on the quantity and quality of microarthropods and microbial communities, and (ii) on the decomposition rate of allochthonous leaf litter. In November 2002, 480 litterbags filled with oak or beech leaf litter were placed into spruce and beech forests (950 m a. s. l.) on Kleť Mt. (1083 m; Blanský les Protected Landscape Area, South Bohemia). Three different mesh sizes were used for certain soil biota exclusion: > 2 mm, 0.5 mm and 42 μm. Litterbags were sampled after 2, 4, 6, 12, 24 and 36 months of exposure in the field. Litter pH and moisture were determined in the laboratory immediately after retrieval. Soil microarthropods (Oribatida, Gamasida and Collembola) were extracted using Tullgren funnels. Soil bacteria and micromycetes were isolated using the dilution plate method and specific growth media.
Klasifikátor založený na inverzních hodnotách indexů II. teorie a příloha
Jiřina, Marcel ; Jiřina jr., M.
A theory of a new method for the classification of data into classes is presented. The method is based on the sum of reciprocals of neighbors' indexes. We show that neighbors' indexes are in close relation to the approximate polynomial transform of the neighbors' distances. The sum of the reciprocals of indexes for all neighbors forms truncated harmonic series due to a finite number of its elements. For the neighbors of one class there is a sum of the selected elements of this truncated series. It is proved that the ratio of these sums gives just the probability that the point to be classified - the query point - is of that class.
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Klasifikátor založený na inverzních hodnotách indexů
Jiřina, Marcel ; Jiřina jr., M.
A new method for the classification of data into classes is presented. The method is based on the sum of reciprocals of neighbors' indexes. We show that neighbors' indexes are in close relation to the polynomial transform of the neighbors' distances. The sum of the reciprocals of indexes for all neighbors forms truncated harmonic series due to a finite number of its elements. For the neighbors of one class there is a sum of the selected elements of this truncated series. It is proved that the ratio of these sums gives just the probability that the point to be classified -- the query point -- is of that class. The classification ability is demonstrated on real-life data from the Machine Learning Repository and the results are compared with published results obtained through other methods.
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