National Repository of Grey Literature 35 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Childhood diet in relation to the determination of social roles and health status in Great Moravian population
Jílková, Michaela ; Brůžek, Jaroslav (advisor) ; Kovačiková, Lenka (referee)
This study is focused on dietary reconstruction according to stable isotope analysis of carbon and nitrogen in bone and tooth collagen. The material used for this study is represented by set of 46 skeletons of adult individuals from 6th church's burial site in Mikulčice, which belong to the Great Moravian era (9th -10th century). Isotopic values are discussed in relation to the formation of social roles and health status. The presence and eventually degree of severity of some non-specific stress indicators and pathologies (Cribra orbitalia, presence of tooth caries, caries intensity, linear enamel hypoplasias, dental wear and length od femur) was observed. The results of isotopic analysis suggest, that diet in this population sample was based on terrestrial sources, both animal and plant protein. Plants in Great Moravian diet belonged to C3 and C4 group. C4 group of plants in Mikulčice was represented by millet (Panicum miliaceum), which supports the hypothesis of "Millet - typical crop of old Slavs" (Reitsema and Kozlowski, 2013). Millet was consumed mainly in childhood. Significant differences between diets of high social class and rest of population was found with people of higher social rank consuming more animal protein. These differences were created in childhood and persisted to adulthood....
Altitudinal migrations in animals and their study methods
Zenklová, Tereza ; Sedláček, Ondřej (advisor) ; Klvaňa, Petr (referee)
Migration as a response to the seasonality of the environment is common in many animal taxa. Strong fluctuation of the climate is usually connected to regions in the temperate zone, quite common is in the tropical regions as well. Typically, it is even more pronounced in high altitudes. In such environment, many animals could migrate altitudinaly as a response to changes in the climatic conditions or food abundance. But determinants of altitudinal and long-distance latitudinal migrations could be different. The objective of this work is to determine factors influencing altitudinal migrations in diverse taxa (particularly in birds and bats) and in different biogeographical regions. I am trying to find some common features of migrating species, such as diet or temperature and rain tolerance. Especially tropical species are partial migrants, which means that only some individuals of the population migrate. I will discuss common features of such migrating infividuals. Study methods of altitudinal migration will be a part of this research as well. The work will be primarily concentrated on tropical regions.
What is the water contribution of fog to atmospheric deposition? Use of stable isotopes.
Hanusková, Darina ; Hůnová, Iva (advisor) ; Šantrůček, Jiří (referee)
The objective of the Master thesis is to estimate the fog contribution on atmospheric deposition with the usage of stable isotopes. The crucial part of the thesis was to perform (first of its kind in the Czech Republic) the relative isotope composition 18 O a 2 H of fog. In the same time, the composition of rain and throughfall was performed. The collection of each type of precipitation took place in five sampling points of Academy of Science within three mountain regions including Krkonoše, Šumava and Jizerské Hory during October and November 2017. The sampling took 14 days in total and it was performed by using TC/EA ThermoBremen and mass spectrometer Delta ThermoBremen at South Bohemian University in České Budějovice. The results confirmed that fog is isotopically heavier in comparison to regular rain. As for the relative isotope composition 18 O and 2 H of each areas, no significant difference was observed. Results of the fog participation on atmospheric deposition in Krkonoše and Šumava can be seen after drafting a simple linear mixing model. The fog contribution on atmospheric deposition in Šumava for 18 O is 4,7 % and for 2 H is 6,4 18 O. For one area in Krkonoše, the average participation for 18 O is 3,6 %. Key words: stable isotopes, oxygen, hydrogen, fog
Multiproxy evidence of Late Pleistocene environmental changes in the loess/paleosol sequence of Bůhzdař
Flašarová, Kristýna
Loess-paleosol sequences preserve information that can be used to reconstruct paleoenvironement, specifically the climatic conditions and the vegetation present at the time of their formation. A dense network of reliably analyzed sequences from different geographic locations is crucial for representation of ecological and climatic trends during the Pleistocene (Frechen, 2011). The aim of this thesis is to fill the gap in the geographical distribution of well described loess-paleosol sequences in Central Europe. Therefore, it focuses on a loess- paleosol sequence in Bůhzdař, situated 9 km NW of Prague, Czech Republic. This profile was last studied in 1952 by naturalist Vojen Ložek. This thesis uses a number of analyses in order to get a multi-proxy record of local paleoenvironmental changes archived in a sequence of alternating loess sediments and paleosols in Bůhzdař. Geochemical approaches are combined with grain size distribution to define climatic conditions at the time of formation of the strata. Key words: loess/paleosol sequences, Bůhzdař, Czech Republic, particle size distribution, total organic carbon, XRF, XRD, stable isotopes 13 C and 18 O
Snowmelt runoff during rain-on-snow events in the Ptačí brook basin calculated using stable water isotopes
Valdhansová, Klára ; Jeníček, Michal (advisor) ; Šípek, Václav (referee)
Rain-on-snow events represent one of the basic mechanisms causing floods. Rain falling on the snow cover causes enhanced melting and the resulting runoff often exceeds the runoff caused by rain. During the winter seasons 2018 and 2019, water samples from the stream, snowpack and precipitation were repeatedly taken in the the Ptačí Brook catchment in the Šumava mountains, and the concentrations of 2 H and 18 O were measured in the laboratory. Based on the observed isotope ratios 18 O/16 O and 2 H/1 H in combination with other variables measured in the catchment, the two ROS events from 2019 were reconstructed. The ratio of heavy isotopes increased in the snowpack due to ROS events. Using the end member mixing equation, a hydrograph separation was performed for both investigated events. For the first event, it was not possible to clearly separate groundwater from rainfall, and thus the range of snow in the total runoff was determined by its separation from rainfall and subsequent separation from groundwater. The second event examined was separated directly into three components: rainfall, groundwater and snow. According to the analyses, the total runoff during ROS events in both cases was mostly formed by event water (a combination of rainfall and melt water). The melting water from the snow cover...
Isotope alteration of carbonate component of Cretaceous sediments from xenolites and vicinity of selected neovolcanic bodies of the Jičín volcanic field
Konečný, Tomáš ; Zachariáš, Jiří (advisor) ; Trubač, Jakub (referee)
The diploma thesis deals with the study of stable isotopes of oxygen and carbon of Cretaceous rocks from the Jičín volcanic field. The aim of the thesis is to identify isotope alterations in Cretaceous sediments transported by basic magmas in the form of xenoliths and to determine the origin of oxygen and carbon of hydrothermal vein carbonates that penetrate the bodies of neovolcanites. The study is divided into two parts. The theoretical part summarizes in general the stratigraphy of the Czech Cretaceous Basin and Cenozoic volcanism of the Bohemian Massif, geochemistry of stable isotopes of oxygen and carbon and geology of studied localities in the Jičín volcanic field. The practical part presents a detailed isotope study of Hřídelec, Kulatý vrch, Zebín, Veliš and Kunětická hora localities. Cretaceous rocks from xenoliths in these neovolcanites show extreme variability in the isotopic composition of both carbon (from 0,15 to -11,1 ‰ V-PDB) and oxygen (from -5,4 to -22,9 ‰ V-PDB). They significantly exceed the variability of the isotopic composition of diagenetically altered Cretaceous rocks from the same area. The wide range of oxygen isotope composition is the result mainly of fluid temperature variability (approx. 300 - 20 řC), which isotopically altered Cretaceous sediments. Carbon isotope...
Multiproxy evidence of Late Pleistocene environmental changes in the loess/paleosol sequence of Bůhzdař
Flašarová, Kristýna
Loess-paleosol sequences preserve information that can be used to reconstruct paleoenvironement, specifically the climatic conditions and the vegetation present at the time of their formation. A dense network of reliably analyzed sequences from different geographic locations is crucial for representation of ecological and climatic trends during the Pleistocene (Frechen, 2011). The aim of this thesis is to fill the gap in the geographical distribution of well described loess-paleosol sequences in Central Europe. Therefore, it focuses on a loess- paleosol sequence in Bůhzdař, situated 9 km NW of Prague, Czech Republic. This profile was last studied in 1952 by naturalist Vojen Ložek. This thesis uses a number of analyses in order to get a multi-proxy record of local paleoenvironmental changes archived in a sequence of alternating loess sediments and paleosols in Bůhzdař. Geochemical approaches are combined with grain size distribution to define climatic conditions at the time of formation of the strata. Key words: loess/paleosol sequences, Bůhzdař, Czech Republic, particle size distribution, total organic carbon, XRF, XRD, stable isotopes 13 C and 18 O
Separation and Elemental Composition of Tardigrades and Rotifers from Cryoconite in Svalbard
Jaroměřská, Tereza ; Žárský, Jakub (advisor) ; Šabacká, Marie (referee)
For years considered pristine, glacial ecosystems are attracting more attention of biologists from various branches in last decades. Moreover, they are currently considered to be ecosystems forming the coldest biome on the Earth. The life on glaciers ranges from viruses and bacteria to highest consumers such as few groups of microinvertebrates. The most common are tardigrades (phylum Tardigrada) and rotifers (phylum Rotifera) which inhabit cryoconite holes on the glacial surface. Several studies highlight the importance of the role of these consumers. However, due to the dominance of prokaryotes on the glacial surface, these microinvertebrates are usually out of the major scope of most studies aiming at biological processes. The present study shows pioneering results on the isotopic composition of tardigrades and rotifers, which are the top consumers in cryoconite ecosystems, and is a foundation for the exploration of trophic pathways and interactions within cryoconite holes using elemental and stable isotopic analyses. It also presents information about the species composition of tardigrades and rotifers on different glaciers and in different parts of the ablation zone. We identified 5 species of tardigrades (Hypsibius sp., Hypsibius cf. dujardini, Pilatobius sp., Isohypsibius sp. and Cryoconicus...
Fish community trophic structure in antrhopogenically perturbed rivers
Dostál, David ; Horká, Petra (advisor) ; Jandová, Kateřina (referee)
Využití stabilních izotopů pro hodnocení trofické struktury společenstev nabývá v posledních dekádách na popularitě a stává se tak stále více používaným nástrojem užívaným k výzkumu trofických pozic a potravních nik. V této práci jsou shrnuty základní principy, které se při práci se stabilními izotopy využívají, představeny mechanismy výměny tkání, izotopového routingu a diskriminačního faktoru, jejichž zanedbání může vést až ke znehodnocení nabytých poznatků. Dále jsou v práci představeny základní metody využití stabilních izotopů, jejich výhody a nevýhody, matematické modely zpracování dat a jejich uvedení do praxe pomocí praktické části, ve kterém bylo zkoumáno trofické postavení a niky kaprovitých ryb v antropogenně ovlivněných řekách.
Nepůvodní druhy raků na Slovensku
LIPTÁK, Boris
Human activities have largely impacted the environment and its biota to the extent that biodiversity declines can be seen worldwide. Biological invasions significantly contribute to these processes. Slovakia is a rapidly developing country stretching along the northern parts of the Pannonian basin and western Carpathian Mountains. Geological characteristics predetermine its extraordinarily high species richness thanks to largely preserved regions and habitats of high biological and conservational value. As a result, a strong population of the stone crayfish occurs in the western part of the country, while there is a countrywide distribution of the noble crayfish. On the contrary, the country's narrow-clawed crayfish is on the edge of extinction. The main reason behind the decline of this species is the expansion of the non-indigenous crayfish species transmitting the crayfish plague pathogen. Although sites of the stone and the noble crayfish occur in the upper parts of the river basins, there is a high risk of crayfish plague outbreaks, since the established spiny-cheek crayfish population are confirmed chronic carriers of the causative agent. Aquarist trade is increasingly recognized as an important pathway for the non-indigenous species introductions, out of which some may establish and become invasive. Freshwater crayfish, shrimp and crab species were recorded in the aquarist trade in Slovakia, counting altogether 26 different species. The marbled crayfish was one of the most frequently traded species. We identified several new sites of the marbled crayfish occurrence with established reproducing populations in very close vicinity of major rivers in the country. One of the newly identified flourishing spiny-cheek crayfish populations is located close behind a bank with a pumping station, i.e. critically close to a sidearm of the Danube River, with a confirmed crayfish plague infection. Marbled crayfish can become a crayfish plague carrier acquiring the pathogen from the infected spiny-cheek population in the Danube and rapidly spreading the disease along the river, thereby endangering the remaining populations of the narrow-clawed crayfish. More sites with the marbled crayfish are expected to occur in the country. Given their parthenogenetic reproduction, theoretically, a single individual is sufficient to establish a new sustaining population. Considering the high availability of the marbled crayfish in the pet trade industry and the rising numbers of established populations in the wild, research clarifying its potential impacts on the invaded ecosystems was warranted. We provide the first study investigating the trophic position and food preferences of the marbled crayfish in its well-established populations. Based on carbon 13C and nitrogen 15N stable isotopes analysis marbled crayfish were identified in the middle of the trophic chain with polyphagic diets. Marbled crayfish were found to utilize algae, allochthonous and autochthonous detritus, zoobenthos and macrophytes, thus being a strong competitor to a wide scale of organisms depended on the same food sources. The marbled crayfish transmit the energy from the bottom of the trophic pyramid to higher trophic levels as it was found to be a prey for top fish predators. This species can form dense populations and become a dominant component of the benthic fauna, thus affecting the entire invaded ecosystem. Its trophic niche width confirms high plasticity of the species, sustaining its populations in a wide range of different habitats. The marbled crayfish is thus a highly adaptable invader that can threaten not only the indigenous crayfish species by means of competition and the spread of crayfish plague, but also entire freshwater ecosystems and their biota.

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