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Hail detection with weather radar data
Skripniková, Kateřina ; Řezáčová, Daniela (advisor) ; Novák, Petr (referee) ; Müller, Miloslav (referee)
The thesis deals with testing of radar-based hail detection methods and their use in hail climatology of Czechia. Data from C-band Doppler radars were used. There is described the testing of the selected algorithms in the first part of the thesis. The algorithms were chosen according to the data availability. On the basis of 25 well documented hail events, suitable threshold values were found to form hail criteria. Because of the hail events considered, the work concentrates on severe hail with diameter from about 2 cm. In addition, available data from Germany (Baden-Württemberg) were included in testing the detection criteria. The best performing criteria were used to form a new combined criterion (COMBI). The second part of the work applies the hail criteria, in particular the COMBI criterion. The performance of the COMBI criterion is shown in four case studies. Then the COMBI criterion was determined from the radar data of the six years 2007-2012. All the days from the months May to August were evaluated. The point maximum of about one day with severe hail was found for Czechia. For the most of the Czech territory the value was not higher than a quarter of a day in a year. In the seasonal distribution the maximum of hail days belongs to June. And the diurnal distribution showed the maximum of severe hail...
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Modular design for in-atomizer preconcentration of hydride forming elements with AAS detection
Novák, Petr ; Kratzer, Jan (advisor) ; Korunová, Vlasta (referee)
Modular design of hydride trap-and-atomizer device for AAS is constructed and tested. Modular design enables to test different preconcentration surfaces easily. Efficient in- atomizer preconcentration allows to reach detection limits of hydride forming elements at ultratrace levels. Bismuth and arsenic were chosen as model analytes and their preconcentration efficiencies were quantified employing quartz and sapphire as preconcentration surfaces. The results reached in the modular design were compared to those found previously in the compact quartz trap-and-atomizer device. The performance of the modular design is fully comparable with that of compact trap-and-atomizer design. Modular design can thus be employed for testing of novel preconcentration surfaces.
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Soviet Economic and Military Aid to Egypt in 1960's and 1970's
Čáp, Jiří ; Litera, Bohuslav (advisor) ; Novák, Petr (referee)
This diploma thesis deals with relations between Soviet Union and Egypt in 1960's and 1970's, with focus on Soviet economic and military aid to this Arabian country. Soviet Union is perceived as a protector superpower, while Egypt is a client state, which receives generous financial and material aid. This work maps particular pe-riods of Soviet economic aid since early 1960's, when some great economic projects were gradually realized (Aswan Dam, Helwan metallurgic complex), the attention is also decicated to arms supplies and modernization of Egyptian army. The first break point influencing mutual relations is Egyptian defeat in Six-Day War in 1967, after which president Nasser was willing to deepen relations with Moscow and even to grant durable Soviet military presence on the Egyptian territory. The period after the inauguration of new president Anwar Sadat in 1970 can be characterized as gradual worsening of mutual relations. The aim of this thesis is to describe particular aspects of Soviet aid and evaluate it in scope of broader political and strategic interests of USSR.
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Molecular mechanisms of apoptosis induction in cancer cells.
Fenclová, Tereza ; Novák, Petr (advisor) ; Milichovský, Jan (referee)
Cancer diseases are now the third leading cause of death (20% of all deaths). It is therefore important to find new ways of getting tumor cells effectively and specifically disposed of and a promising path is targeted therapy. One of the most frequently deregulated protooncogenes in cancer is C-MYC, which makes it suitable as an effective target for treatment. However, the development of such targeted active ingredients is very expensive, so in this thesis we investigate natural substances that have been used for the treatment of cancer in ancient China. We examined the substances shikonin, cnicin and artemisinin. The results show that shikonin induces apoptosis of tumor cells by reducing the expression of C-MYC and activating tumor suppressor kinase MST1. Cnicin reduces the expression of C-MYC as well, but activates MST1 only weakly. Artemisinin, on the other hand, increases expression of C-MYC and doesn't activate MST1, thus operates on inducing apoptosis of tumor cells by a completely different mechanism. (In Czech)
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Estimation of the survival function in the reliability analysis
Vojtěch, Jonáš ; Novák, Petr (advisor) ; Hurt, Jan (referee)
Present Bachelor thesis deals with the basic concepts and methods used in the survival analysis. Both nonparametric and parametric approaches to the estimation of the survival function are described. Nonparametric Kaplan Meier method is presented in order to estimate the survival function and consequently derive its basic properties. From the point of the probability distributions used in the analysis of reliability, exponential, Weibull's and logarithmic-normal distri- butions are applied. Parameters in the parametric approach to the estimation of the survival function are determined by the modification of maximum likelihood method for censored data. From the tests that are proper for the comparison of distribution of the duration of survival of more groups, nonparametric logrank test and parametric likelihood ratio test are mentioned. In the last section of the Bachelor thesis the theoretical findings are illustrated on simulated as well as actual data using Mathematica 9. Keywords: survival function, Kaplan-Meier estimator, logrank test, maximum likelihood method, likelihood-ratio test 1 Literatura 2 Seznam obrázků 3 Seznam tabulek 4
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Poisson process
Kráľová, Veronika ; Beneš, Viktor (advisor) ; Novák, Petr (referee)
Poisson process is a random set, which analyses an occurrence of the independent random points in a certain set. An object of study are probabilistic properties of this random set. Basic definitions and properties are formulated for the Euclidean spaces of arbitrary dimension and used to simulate different types of Poisson processes. We provide the algoritm procedures and source codes for each simulation. Statistical test of complete spatial randomness (CSR) verifies in conclusion, if the simulated processes are really homogeneous Poisson processes with specific properties.
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Mass Spectrometry-Based Identification of a Potential Binding Partner of Glutamate Carboxypetidase II
Tužil, Jan ; Konvalinka, Jan (advisor) ; Novák, Petr (referee)
English Abstract The incoming paradigm of the network (or systems) biology calls for a new high throughput tool for a wide scale study of protein-protein interactions. Mass spectrometry-based proteomics have experienced a great progress in recent years and have become an indispensable technology of elementary as well as clinical research. Glutamate carboxypeptidase II (GCPII; EC 3.5.17.21) is a transmembrane protein with two known enzymatic activities. Its expression is highly upregulated in some solid tumors and also in tumor-associated neovasculature in general. Nevertheless, none of the two enzymatic activities were shown to be physiologically relevant to these cells. Some facts point at a possible receptor function of GCPII, however, no specific binding partner has been found yet. In the search for potential binding partners and/or ligands of GCPII, a series of methods have been employed, including pull-down experiment, immunoprecipitation and mass spectrometry. Sample preparation and mass spectrometry data processing methodology was specifically developed in order to identify potential binding partners. As one of the outcome of that methodology, the interaction of β-subunit of F1 ATP synthase was selected for further detailed analysis as a putative ligand of GCPII.
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The role of mitochondrial metabolism in initiation and adaptation to hypoxic conditions.
Rohlenová, Terezie ; Novák, Petr (advisor) ; Rohlena, Jakub (referee)
We can meet pathological hypoxia in the cases of hearth attack, ischemic stroke, but also during tumor invasion, thanks to insufficient angiogenesis. The activation of HIF- 1 factor during hypoxic conditions is crucial for the cell survival. This factor modulates energetic metabolism in favor of fast progressing glycolysis (with the contribution of glutaminolysis) which provides to cell enough ATP and "building blocks", while suppressing Krebs cycle and respiration because of shortage of oxygen. The thesis studies energetic metabolism of HepG2 cells (derived from liver carcinoma) which are cultivated in the media with various energetic substrates, i. e. glucose or galactose (always together with glutamine and pyruvate) under the hypoxic conditions (5% O2). HepG2 cells use particularly oxidative metabolism for ATP and "building blocks" production under the normoxic conditions while hypoxic environment causes metabolic shift in glycemic condition. Interestingly, cells cultured in galactose (glutamine) didn't switch the energy metabolism from oxidative to aerobic glycolysis such as cells cultivated in glucose, although HIF-1 factor was stabilized. We found that enhanced activity and integrity of mitochondria, enhanced maximal capacity and reserve capacity of respiration chain correlates with...
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Severe lightning activity over the Czech republic
Uhlíková, Tereza ; Novák, Petr (advisor) ; Kyznarová, Hana (referee)
This work comprises an introduction to study of lightning and presents data about daily amount of lightning flashes over the Czech Republic (CR) in period 2002-2012. For selected days in this period, there are introduced and examined some meteorological characteristics. There are presented an evolution of lightning discharges and contemporary options for lightning detection which contain ground-based systems and satellites systems. Main advantage of ground-based systems are location accuracy <1 km and additional information which could be provided about every single stroke which is e. g. polarity or peak current. The benefit of satellite lightning detection is the large covera- ge which is useful for a global view of lightning activity on the Earth. After that, the general climatology of lightning in the world is introduced. The land-ocean contrast in lightning activity is presented (lightning activity over land is up to two orders higher than over the ocean). There is also information about maximum amount of flashes over equatorial Africa. The hypothesis explaining the land-ocean contrast in lightning activity and African maximum are included. Climatological charakteristics of lightning in selec- ted European countries are mentioned in the last section. In analytical part of the work, single years...
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Studies on structure and biological functions of NKR-P1 receptors
Rozbeský, Daniel ; Novák, Petr (advisor) ; Konvalinka, Jan (referee) ; Drbal, Karel (referee)
Natural killer (NK) cells play a significant role in the detection and destruction of virally infected and tumor cells. The NKR-P1 receptors regulate NK cell function by an alternative missing-self recognition system. Although the NKR-P1 receptors were among the first surface NK receptors identified on rodent NK cells more than 20 years ago, there is still very little known about their biological function and their physiological ligands. Furthermore, no three-dimensional structure of any of the NKR-P1 family receptors has been published so far. To understand the functional architecture of mouse NKR-P1 receptors, we developed a simple and efficient protocol providing large amounts of pure soluble NKR-P1 proteins. The crystal structure of mouse NKR-P1A, determined at 1.7 A resolution, is the first structure of a representative of the NKR-P1 family. Crystal structure is formed by a compact C-type lectin-like domain and an extended loop that participates in domain swapping. A potential role of the swapped loop has been suggested in natural ligand binding by in silico studies. However, chemical cross-linking and H/D exchange in combination with high resolution mass spectrometry revealed this loop in close proximity to the compact core in solution. The discrepancy between the crystal and solution structure...
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