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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Dynamika výdeje CO2 modelového mokřadního ekosystému / Dynamics of CO2 output in model wetland ecosystem.

STELLNER, Stanislav January 2015 (has links)
The main objective of this work was to evaluate the dynamics of CO2 and CH4 emissions from wetland soil of the sedge-grass marsh, which belongs to large complex of wet meadows near Třeboň town. CO2 and CH4 emission measurements realized on six places, where gas emission collars permanently inserted. Finally, samples of air were taking with using manual emission gas chambers within period from April 25th to November 24th 2014. The highest fluxes of CO2 were recorded in June and July. The lowest water level was recorded in this period together with low fluxes of CH4. Methane emissions were higher in September and October at the time where water level was above soil surface. Range of CO2-C fluxes was -9.38 mg m-2 h-1 (consumption) to 147.84 mg m-2 h-1 (emission). Range of CH4-C fluxes was -14.94 ?g m-2 h-1 (consumption) to 5561.67 ?g m-2 h-1(emission).
2

Změny ve vývoji mokřadů v krajině – trajektorie, příčiny / Changes in wetlands - change trajectories, causes

Brašna, Vlastimil January 2016 (has links)
This thesis analyzes the historical development of wetlands in corn production areas in Moravia, Czech Republic. Wetlands were analyzed changes in time and space for a period of 180 years. The main objective is to analyze the development of wetland habitats in the landscape using old maps, aerial photographs and GIS. The bases were of the Imperial Imprints of the Stable cadastre from the first half of the 19th century and contemporary orthophoto. There were also used GIS layers of the current location of wetlands, farmland, forests, rivers and waterways. In historical documents were evaluated by two categories 1) wet meadows and 2) swamps and marshes. In the current surface are only evaluated wetlands. The total area is 18054 ha. The area of wetlands dramatically decreased from 108 ha in the first half of the 19th century on 14 ha in 2015. Most of the wetlands have been converted to agricultural land - arable land (72 %), meadows and pastures (12 %). Wetlands succession was transformed to bushes (5,4 %). There was 5 % of the deaths of wetlands built and drained. Most wetlands have been transformed due to the pressure on the production function of the landscape in order to get more food. In the first half of the 19th century it was dominated by wet meadows, they had 684 ha. Despite the disappearance of a large part of the wetlands created new wetlands, which have 12.4 hectares. Most newly created wetlands are located in the cadastral area of Mutěnice. Only one wetland (1.68 ha) remained unchanged, located in cadastral Čejč. This wetland had a history of more land (25.15 hectares) and has been linked with Čejčské Lake. The main result of this work is to determine the trajectories of development of wetland ecosystems in the lowlands of Moravia. Descriptions of these trajectories have contributed to understanding influences on the development of wetlands. Results wetlands contribute to the development of knowledge in the field of landscape ecology. The results can be used to restore extinct wetlands and creation of new wetlands in the historic wet meadows. The information obtained can be used in landscape planning with regard to the protection and management of wetlands.
3

Trajektorie vývoje mokřadů v krajině nížin a pahorkatin České republiky / Change trajectories of wetlands in the landscape of lowlands and uplands in the Czech Republic

Richter, Pavel January 2015 (has links)
Wetland habitats are of great multifunctional importance in landscape. In particular, they have the capacity to retain water during its surplus and then in the dry season to release the water. In this work the dynamics of change in wetlands coverage was analyzed, including the representation structure of different categories of wetlands over the past 180 years in the landscape of lowlands and uplands in the Czech Republic. The historical maps of Stable Cadastre, current orthophoto and current GIS layers of localization and classification of different types of land use/cover and landscape types were used as data sources. The area of wetlands has dramatically decreased from 5 762 hectares in the period 1825-1843 (more than 9.5 % of the area) to 54 hectares in 2014 (0.9 %). Based on the study of available documents three types of wetland habitats were classified: wet meadows, wet meadows with trees and swamps . Although, the most of the historic wetlands were constituted of wet meadows (89 %) these days the swamps (48 %) form the largest part of the wetlands. Half of the historic wetlands were transformed to arable land because of increasing production of agriculture. According to the evaluation of monitored changes by predictors it was found that more pressure on the degradation of wetlands was in the areas with more suitable climatic conditions for agriculture (e.g. The Danube basin, Moravia, soil types in the lowlands, Corn agricultural production area etc.). In these areas the swamps were formed as new wetlands in places of historical watercourses localization more significantly than elsewhere in monitored area. The aim of this work was also to describe the main driving forces and pressures that have influenced the changes in wetlands. The outcome of the paper can be used in landscape planning with regard to the protection and management of wetlands.
4

Dekompozice nadzemní biomasy travinného mokřadního porostu / Decomposition of aboveground biomass of a herbaceous wetland stand

KLIMOVIČOVÁ, Lucie January 2012 (has links)
The master?s thesis is part of the project GA ČR č. P504/11/1151- Role of plants in the greenhouse gas budget of a sedge fen. This thesis deals with the decomposition of aboveground vegetation in a herbaceous wetland. The decomposition rate was established on the flooded part of the Wet Meadows near Třeboň. The rate of the decomposition processes was evaluated using the litter-bag method. Mesh bags filled with dry plant matter were located in the vicinity of the automatic meteorological station at four randomly selected sites. Values of the decomposition rate were assessed in two experiments. In the first experiment the litter bags were fixed in April 2009. The litter bags were fixed in the vertical position and they had one size. Values of the decomposition rate were assessed for 6 sampling dates and the total exposure time was 2,5 years. The decrease of the total dry mass was 18,37 % in the first year and 13,05 % in the second year. The value of LDR was 0,7227 in the first year and 0,4740 in the second year. In the 2nd experiment the litter bags were fixed in November 2010. The litter bags were fixed in the vertical and horizontal position, respectively, and they were of two sizes (small, big). Values of the decomposition rate were assessed for 2 sampling dates and the total exposure time was one year. The total annual value of LDR was 0,5212 for the vertical bags and 1,0676 for horizontal bags.
5

Ptáci řádu Passeriformes otevřené krajiny v CHKO Třeboňsko / Birds of Passeriformes order on CHKO Třeboňsko champaign

FUKA, David January 2008 (has links)
During the breeding season in 2007, the mapping of the nesting ranges in birds of the order Passeriformes was carried out on the chosen localities in Třeboň wet meadows within the Třeboňsko landscape; Aim of study was to order qualitatives and quantitatives status of the Passeriformes within localities and their comparasion. Localities were situated in the immediate vicinity of Třeboň. The total mapped area was 25 hectares. The Vegetation was dominated by tall sedges (locality New station). The principal biotops consisted of tall sedges biotop M1.7 and K1 (locality New station and locality Old station) and V1 biotop. Within Old station locality and Opatovický locality it was especially: T1.5 and T1.4 and X5. Nesting birds were counted by the mapping method (Janda a Řepa, 1989). The GPS system was used for the recording of single males. Twenty three passerine bird species were found within localities. In total, nine bird species were founded in all the localities. The most abundant species were: (Acrocephalus schoenobaenus) the Sedge Warbler, (Luscinia svecica cyanecula) the Bluethroat, (Locustella naevia) the Grasshopper Warbler (Old station locality and New station locality), Opatovický locality was dominated by Acrocephalus schoenobaenus the Sedge Warbler. There was signigicant differences of total density of bird assemblage betwen Opatovický locality and New station locality and Old station locality and Opatovický locality. High breeding density was found especially in the Whinchat and the Bluethroat on New station locality. High conformity of bird assemblage was among New station locality and Old station locality.
6

Nadzemní produkce porostu zaplavované louky s dominantní ostřicí štíhlou (Carex acuta) / Aboveground production of a wet meadow stand dominated by Carex acuta

KUNCOVÁ, Štěpánka January 2009 (has links)
The MSc thesis is part of the project of Ministry of Environment of the Czech Republic entitled Czech Terra, which aims at assessing the carbon budget and cycle in the main types of ecosystems in the Czech Republic. This thesis is focussed on the production of aboveground biomass of Carex acuta, which dominates the unmanaged and permanently flooded part of the Wet Meadows. The seasonal dynamics of aboveground plant production was followed using a series of 9 destructive harvests during the vegetation season. On each date, four 0.5x0.5m2 samples were taken from the wetter, and four samples from the drier part of the stand. The maximum value of live biomass of C. acuta (550.8 g.m-2) was recorded on 13.6 2008. The highest value of live biomass of all species reached 602.4 g.m-2. The maximum total biomass (without litter) reached 994.6 g. m-2. The highest value of productivity of C. acuta (12.46 g.m-2.day-1) was recorded on 24. 5.
7

Vliv dostupnosti minerálních živin a zaplavení na růst ostřice štíhlé v nádobovém pokuse. / Effect of mineral nutrient availability and flooding on the growth of Carex acuta in a mesocosm experiment

SYCHROVÁ, Jana January 2011 (has links)
This MSc thesis is part of the project GACR 526/09/1545 Importance of newly assimilated carbon for the plant-soil interactions in wet grassland ecosystems in varying environmental conditions, which focuses on the effects of eutrophication on selected wet meadows with mineral or organic soil in the Trebon Biosphere Reserve. The results of this project will serve as a basis for developing a suitable ecosystem management for wet meadows, especially for sites registered as nature reserves. Pot experiments were carried out with Carex acuta, a dominant species of wet meadows that has already been subject of many studies. The aim of this work was to find out how C. acuta responds to different levels of fertilization and soil flooding under controlled conditions. The growth of the generative shoots of C. acuta was significantly affected by fertilization. The growth of vegetative shoots was significantly influenced by the soil organic matter content and fertilizer addition. The vegetative shoots reached greater length than the generative shoots. The pot experiment indicates that fertilization has not a large influence on the growth of C. acuta. This finding may explain field observations that C. acuta is gradually replaced in eutrophic habitats by stronger competitors, especially Phalaris arundinacea.
8

Vliv podleptání plazmonických antén na jejich optickou odezvu / Influence of underetching of plasmonic antennas on their optical response

Novák, Martin January 2017 (has links)
Influence optical response on underetching of plasmonic antennas is observed in this thesis. When light falls with resonant wavelength on the optical antennas, the electromagnetic field is amplified near this antennas. The resonant wavelength depends on the length of the antenna and on effective refractive index given by the ambient properties around the antenna. The contact surface with substrate (dielectric) is reduced by underetching the antenna and the effective refractive index is changed and thus the optical response of the antenna is changed.
9

Sledování jakostních ukazatelů při zrání masa divokých prasat

Vicenec, Ondřej January 2018 (has links)
This diploma thesis looks at the indicators of quality in the wild boar meat maturing process. The duration of the meat maturation (Musculus longissimus dorsi) was compared in 25 wild boars depending on the meat cut, the age of the hunted wild boar, where the animal was shot, the type of hunt and the season in which the wild boar had been hunted. The wild boar meat was wet-aged, sliced into pieces approximately 2 cm wide and the duration of aging was split into three intervals (0 to 5 days, 6 to 10 days and 11 to 15 days). The pH of the meat, its texture, colour and the sensory properties of the cooked meat and broth were determined after each interval. During the maturing process, the lightness of the meat L* grew rapidly and showed a statistical significance (p < 0,01), the redness of the meat a* on the other hand declined (p < 0,01). The volume of yellow colour b* did not change during the maturing process. The duration of aging did not effect the pH in the meat and showed no statisti-cal significance. Convincing differences were noted in the measurement of the texture of the maturing meat. Tenderness was most notable after a period of 6 to 10 days. The duration of aging showed a statistical significance (p < 0,05) in: taste intensity, juiciness, tenderness and texture of the meat. The duration of aging also showed statistical significance (p< 0,05) in all the analysed descriptors of the meat broth (taste intensity, pleasantness of taste, aroma intensity and the pleasantness of the aroma).
10

Technology of monofilamentous fibers based on oxidized hyaluronic acid / Technology of monofilamentous fibers based on oxidized hyaluronic acid

Běťák, Jiří January 2016 (has links)
Předkládaná dizertační práce se zabývá vývojem technologie výroby nového typu biodegradabilních vláken na bázi oxidované kyseliny hyaluronové. V rámci práce je postupně představován vývoj jednotlivých jednotkových operací výroby, jejichž správné porozumění a schopnost jejich řízení jsou klíčové pro žádaný chod celé vícestupňové technologie. V rámci práce je představen nezbytný vývoj technologického zařízení, průběžně konstruovaného pro účely laboratorního testování a následně až po samotnou linku pro finální výrobu vláken, která byla realizována v roce 2015. V rámci dizertační práce jsou dále navrhovány možnosti dodatečné chemické úpravy vláken s ohledem na zvyšování jejich stability ve vlhkém prostředí. S ohledem na cílené aplikace vláken pro vnitřní chirurgické implantace, jsou v práci vlákna též hodnocena z hlediska jejich materiálové biokomaptibility (toxicity).

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