National Repository of Grey Literature 5 records found  Search took 0.01 seconds. 
Changes in nutrient availability imprinted in long-term diatom succession in lakes
Tichá, Anna ; Kuneš, Petr (advisor) ; Magyari, Enikő Katalin (referee) ; Catalan, Jordi (referee)
An examination of primary production in lakes shows regular trends during the Late Glacial and the Holocene periods: an increase ('eutrophication') and a decrease ('oligotrophication') usually connected with the input of terrestrial organic matter ('dystrophication'). Although nutrient availability usually influences production, other abiotic and biotic factors enter lakes' complex ontogeny, such as light availability, mixing regime, pH level, mechanical disturbance, predation or competition. Consequently, the past relationship between nutrient availability and primary production contains important information about the drivers of ecosystem functioning in the past. The reconstruction of past processes relies on the sensitive response of aquatic organisms to environmental changes. Their subfossil remains record the dynamic processes in the sediments and reveal both the local lacustrine history and more global events. Among other organisms, diatoms fulfil their function as a valuable proxy of past physical and chemical properties of water bodies. Whereas the record of planktonic diatom species dynamics represents the general ecosystem condition, variations in species-rich littoral periphytic diatoms add necessary insight into finer environmental fluctuations. The presented research combines...
Changes in biological monitoring of running waters using benthos with respect to diatoms
Fiedler, Jan ; Kulichová, Jana (advisor) ; Tichá, Anna (referee)
This work focuses on the development of a methodological approach to biomonitoring of running waters using benthic organisms. It discusses the development from methods focused on determining organisms by their external appearance to modern biomonitoring based on the determination of organisms by eDNA metabarcoding. Modern metagenomic methods (genomics, transcriptomics, metabolomics and proteomics) are also mentioned. This thesis compares the development of ecological status assessment of freshwater ecosystems using diatoms and invertebrates. It also describes the common points of their methodological development. Another outcome of the comparison is information on which hydrochemical and geochemical environmental factors can be easily monitored by diatoms and which by macroscopic invertebrates. Furthermore, a prognosis for the further development of biomonitoring is mentioned in the conclusion. It is formulated as a synthesis of traditional methods based on morphological species determination, biomonitoring 2.0 (using eDNA metabarcoding) and metagenomic methods. Key words: autecology, morphospecies, sequencing, biotic index, pollution
Pretreatment of hops for further processing in beer technology
Tichá, Anna ; Štursa, Václav (referee) ; Pořízka, Jaromír (advisor)
This diploma thesis deals with pre-treatment of hops for further processing in beer technology. In the experimental part of the work, the effect of low temperatures, as pre-treatment of hops, on the monitored parameters was observed. Three types of cold pretreatment were used. In two cases, the hop material was frozen using a freezer at -25 ° C and in the second case at -70 ° C. In the third case, the hop material was treated by contact with liquid nitrogen in combination with mechanical treatment. The variety of hop materiál was Žatecký poloraný červeňák, which were in the form of pellets or pressed hop cones. The total bitterness of the samples, the total content of phenolic substances, the total content of flavonoids, the antioxidant activity and the concentration of essential oils, specifically myrcene humulene and geraniol, were examined. The effect of pre-treatment was investigated during conventional worth boiling as well as dryhopping. The experimental part includes descriptions of the hopping process, descriptions of individual analytical methods. A parallel measurement was performed on each sample. Significant advantages or disadvantages of some of the pretreatments were not demonstrable, however, the most significant differences were observed in samples hopped with hops pretreated by freezing at -70 ° C, which had a positive effect on the amount of extracted essential oils during cold hops.
Monitoring the stability of the beer brewing process
Tichá, Anna ; Štursa, Václav (referee) ; Diviš, Pavel (advisor)
The bachelor thesis deals with the analysis of 3 samples of the same beer, brewed in different batches of the brewing process. The analyzed sample is Dalešická jedenáctka - light lager of 11% of the Stock Brewery Dalešice, a.s., which was taken directly from the lager tanks in the brewery. The aspect we have examined were total protein content, total carbohydrate content, maltose content, total polyphenol content and ethanol content. The Hartree-lowry method was used to analyzed the total protein content. Total carbohydrates were measured spectrophotometrically using anthrone reagent. The maltose content was analysed by HPLC with an ELSD detector. The total polyphenol content was analyzed by the Folin-Ciocaltau reagent method and measured spectrophotometrically. The ethanol content was analyzed on a HPLC using a refractometric detector. The aim of the work was to compare to what extent the process of beer production is stable and what parameters may change in the final product

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4 TICHÁ, Anna
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6 Tichá, Alžběta
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3 Tichá, Anděla
1 Tichá, Aneta
8 Tichá, Anežka
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