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Arctic tundra dendrochronology
Lehejček, Jiří ; Svoboda, Miroslav (advisor) ; Monika, Monika (referee)
Historically unprecedented environmental change in the Arctic ecosystems is often given into the context of its past and possible future development. In the region where instrumental meteorological observations are scarce archives need to be investigated in order to address this issues. The comprehensive synthesis one of the archives: long-live circumpolar evergreen Juniperus communis L. shrub is presented here. 20 individuals from southwest Greenland were investigated at the cell anatomy level to understand the ecology of the species and unhide its potential for environmental and climate reconstructions. The findings are as follows:
i) Stop of exponential cross-sectional conduit-lumen widening with increasing age is in contrast with conduit-lumen nature of trees. This indicates that shrubs do not need to saturate their water and nutrient demands via traits of classical hydraulic conductivity law but rather developed different mechanisms. Extreme weather conditions result in prostrate growth form. However, different weather factors probably influence shrub growth differently: While snow and wind act mechanically (a), temperature influences the form of growth physiologically (b). a) So long as the young shrub stem has high resilience to bend back to an upright position after snow melt and so long as it can withstand the wind during the vegetation season it most likely grows upright and the conduit-lumens widen. b) Temperature, resp. freeze-thaw events are responsible for the shrubs preference of safety (finite size of conduit-lumens) over hydraulic efficiency, thus not allowing for more primary growth. All of these (and other) factors are apparently working together and the transition of vertical to more horizontal growth is gradual. As a consequence, the conduit-lumen sizes may not have to be further increased (due to ecophysiological restrictions possibly also must not) because water is no longer transported against gravity.
ii) Observed age/growth trend has to be taken into consideration for further employment of the wood anatomical parameter in paleoenvironmental studies. That is, shrub cell parameters can only be used for this purposes if correctly detrended. This allows for more accurate as well as longer reconstructions because youth trend was often neglected in reconstructions based on shrub annual-rings.
iii) The south-western Greenland Ice-Sheet (GrIS) melt rates reconstruction is presented for the whole 20th century. This part of GrIS is considered as the most active. According to the presented reconstruction current GrIS melt rates are not uncommon for the last century being comparable to first decades of 20th century. This finding is particularly important contribution to the debate on Atlantic meridional overturning circulation (AMOC). Too high fresh water inputs into the Northern Atlantic from GrIS melting may slow down or even stop the AMOC which would result in more continental climate in Europe. Presented results indicate that this threshold lies higher than observed current melt rates of GrIS.
Fascinating Juniperus comunnis species has shown to be able to address many ecological as well as environmental open questions and due to its longevity and abundant distribution has a great potential to become an important player in the Arctic research.
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Nutritional analysis and optimization of breeding of selected species of edible insects under conditions of the Czech Republic with regard to human health
Adámková, Anna ; Kouřimská, Lenka (advisor)
All over the world, the edible insects are considered a highly nutritious food with high protein and fat content. However, the nutritional value of insect is not constant. It can be affected by species, developmental stage, rearing technology or nutrition.
Therefore, this thesis was aimed at obtaining the selected nutritional value of edible insects. Analyses were focused on the determination of the crude protein content, fat content, fatty acid profile and sterols in selected species of edible insects, which can be commonly reared in the Czech Republic. At the same time we also analysed samples of insects reared on the island of Sumatra to evaluate the influence of the climate on the nutritional value. The main aim of the thesis was the determination of optimal breeding conditions, developmental stages and feed rations for obtaining good production of insects with nutritional properties suitable for human nutrition. The analyses showed a high nutritional value of selected insect species, but also confirmed the significant differences in the content of individual nutrients between different species depending on the climate conditions and developmental stage. Comparing the fat and crude protein content in edible insects and other conventional sources of meat it has been found, that the examined insect is similar to beef concerning the fat and crude protein content. The results obtained are the basis for determining the appropriate rearing conditions and developmental stages for obtaining insect with the desired nutritional properties for human nutrition.
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Population genetic analysis of Old Kladruber horse
Vostrá Vydrová, Hana ; Majzlík, Ivan (advisor) ; Karel, Karel (referee)
The Old Kladruber horse, along with the Lipizzaner horse, Andalusian horse and Lusitano horse, is of the original Italo-Spanish type. The Old Kladruber horse is kept in two colour varieties (grey and black). Because the population is closed, there is a concern about the loss of genetic variation. The genetic diversity and population structure were analysed in the Old Kladruber horse breed based on the pedigree information of animals that were registered in the Studbook to identify factors that may have affected the genetic variability of the breed. Pedigree records collected from 1729 to 2013 contained information on 7971 animals that were used in the analyses. The pedigree depth was up to 33 generations, with an average of 15.1 complete generations. The effective number of founders and ancestors contributing to the current genetic pool was 92.69 and 17.16, respectively. The average values of the inbreeding coefficient were as follows: 13% (with a maximum value of 29%) for the reference population (individuals that can currently take part in reproduction, n=612), 11% for the grey variety (with a maximum value of 25%) and 15% for the black variety (with a maximum value of 29%). The proportion of inbred animals was high (99%). The average rate of inbreeding in the reference population was 1%: 0.8% for the grey variety and 1.1% for the black variety, and the respective estimates of the effective population sizes were 52 for the reference population, 62 for the grey variety and 45 for the black variety. The estimated percentage of genetic diversity lost due to non-random mating within subpopulations and the reference population was 1.0, 1.0 and 1.2%, respectively. The total loss of genetic diversity in the reference population, in the grey variety and in the black variety was 11%, 13% and 17%, respectively.
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The use of biomass ash
Ochecová, Pavla ; Tlustoš, Pavel (advisor) ; Radim, Radim (referee)
One of the most frequently used sources of renewable energy is biomass, mainly wood biomass. Incineration is the most common technology utilizing the energy from biomass to produce heat. A byproduct of these technologies is ash, whose composition depends on the feedstock composition and the incineration technologies. Due to the high content of valuable nutrients in ash, one of the suitable option for ash utilization seems to be application into agricultural or forestry land. Therefore, it is necessary to test response of soils and plants and look for the most suitable combination of soil additive (biomass ash), and plants. Experimental part of PhD thesis was divided into the incubation experiment and the vegetation pot experiments. The incubation experiment: The efficiency of ash addition at two application rates was tested for nutrients enrichment in different soils within period of 56 days. The vegetation pot experiments: The two plants Triticum aestivum L: (three-year experiment) and Lolium perenne L. (one-year experiment) were planted in the 5L pots. Soils were treated with ash or ash combinated by superphoshate and flue gas desulfurization gypsum. For both plants, we evaluated the plant growth, biomass production and content of macro, micro and toxic elements in the biomass and in the soils.
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Comparison of the Views and Attitudes of Pupils at Secondary Vocational Schools in the Field of Substance Abuse
Mazánková, Michaela ; Jirsáková, Jitka (advisor) ; Miroslava, Miroslava (referee)
Bachelor thesis entitled Comparison of the views and attitudes of pupils at secondary vocational schools in the field of substance abuse deals with a comparison of opinions and attitudes of pupils at secondary schools and vocational schools Obchodní akademie a Hotelová škola Havlíčkův Brod. The first part is devoted to general characteristics of risky behavior, causes of its origin, different types and prevention of risk behaviors . Analytical part is devoted to evaluation of the questionnaire and the results are compared opinions and attitudes of students of graduation schools and vocational schools, and point to the simultaneous occurrence of risk behavior studied in high school. Based on data evaluation are at the end of the work proposed specific preventive measures specifically for students of graduation schools and vocational schools.
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Cooperation of high schools with external contractors in preparing school educational programs
Tulach, David ; Lačev, Alek (advisor) ; Hochel, Matej (referee)
This thesis, Cooperation of high schools with external contractors in preparing school educational programs, deals with the question whether it would be possible and beneficial for high schools to cooperate with companies on the preparation or modification of their educational programs, with the goal of improving the quality of education. After initial contributions from experts who provided negative replies to this question, the view was focused on the root of the issue - what are the historical pillars of public schools and pedagogy, what does science say about learning and teaching, how pedagogy reacts to the crisis of science. After comparing literal sources and results from interview with the experts, in combination with a trace and activity analysis, a theory was established that public education is reaching a point of crisis, has not changed in its essence since its beginning and that the best solution might be the establishment of alternative educational institutions.
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Predicting asp and pikeperch recruitment in a riverine redervoir.
BLABOLIL, Petr
Recruitment of two species, asp (Leuciscus aspius) and pikeperch (Sander lucioperca), in a riverine reservoir was studied using a novel statistical approach. Both species are piscivorous and are stocked into reservoirs for biomanipulative purposes to reduce planktivore species. Long-term data series were used, but the number of potential predictors was high. Therefore, a novel informative statistical approach based on dimension reduction methods was applied. Quality of outputs was driven by sampling methods. Main factors affecting asp recruitment were zooplankton abundance, predator density and temperature. In terms of pikeperch fry measured with seine and trawls, the number of predators was the only important factor. Gillnets underestimate small fish and the data were unsuitable for statistical modelling.
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(100) substrate processing optimization for fabrication of smooth boron doped epitaxial diamond layer by PE CVD
Mortet, Vincent ; Fekete, Ladislav ; Ashcheulov, Petr ; Taylor, Andrew ; Hubík, Pavel ; Trémouilles, D. ; Bedel-Pereira, E.
Boron doped diamond layers were grown in an SEKI AX5010 microwave plasma enhanced chemical vapour deposition system. Effect of surface preparation, i.e. polishing and O2/H2 plasma etching on epitaxial growth on type Ib (100) HPHT synthetic diamonds were investigated. Using optimized substrate preparation, smooth (RRMS ~ 1 nm) boron doped diamond layers with metallic conduction and free of un-epitaxial crystallites were grown with a relatively high growth rate of 3.7 μm/h. Diamond were characterized by optical microscopy, optical profilometry, atomic force microscopy and Hall effect.
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Frequency stabilized semiconductor laser source for high-resolution interferometry
Řeřucha, Šimon ; Hucl, Václav ; Holá, Miroslava ; Čížek, Martin ; Pham, Minh Tuan ; Pravdová, Lenka ; Lazar, Josef ; Číp, Ondřej
We have assembled an experimental iodine stabilized Distributed Bragg Reflector (DBR) diode based laser system lasing at a wavelength that is in a close proximity to the wavelength of a stabilized He-Ne lasers traditionally used for metrological applications (λ=632.9 nm in vacuum). The aim was to verify whether such a system could be used as an alternative to the He-Ne laser while yielding wider optical frequency tuning range, higher output power and high frequency modulation capability. We have measured the basic characteristics of the laser source and then we have compared the performance of the laser system with that of a traditional frequency stabilized He-Ne laser with a series of experimental arrangements similar to those usually found in laser interferometry and displacement metrology applications. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology since it provides more output power and advanced tunability options than stabilized He-Ne lasers while maintaining fundamental requirements such as the frequency stability, coherence length and also a defined traceability.\n\n
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Optical low dispersion rezonator as length sensor using optical frequency comb
Pravdová, Lenka ; Hucl, Václav ; Lešundák, Adam ; Lazar, Josef ; Číp, Ondřej
Ultra-high precis measurements are domain of lasers interferometers. An optical resonator measuring method using broad spectrum of radiation of an optical frequency comb was designed and experimentally verified at our workplace. The measuring of a quantity – a distance of resonator mirrors – is provided by its conversion to the value of repetition frequency of the pulse laser with mode-locked optical frequency comb. In this paper the comparison of the absolute scale of the optical resonator with an incremental interferometer scale is introduced. The incremental interferometer is implemented for verification of the optical resonator scale. The double beam incremental interferometer is operating at the wavelength of 633 nm and the measuring mirror with piezo actuator is used as one of its reflectors. It turns out that the major error signal is the reflection of the periodic nonlinearity of the incremental resonator scale. The relative resolution of our method reaches values up to 10-9 while maintaining measuring scale.
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