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Environmental factors determining distribution of genders in dioecious plant species
Hatajová, Klára ; Münzbergová, Zuzana (advisor) ; Čertner, Martin (referee)
This bachelor thesis investigates the effect of environmental factors on the ratio of males to females in populations of dioecious plants, and their different physiological and morphological changes caused by environmental stress. Although the sex of plants is determined genetically, environmental factors can influence mortality in one sex more or even cause the sex change of individuals. This thesis summarizes studies showing that females in dioecious plants are much less able to withstand environmental stress, mainly due to their increased demand for reproduction. Thus, females may have higher mortality than males, limiting the reproductive potential of the entire population. Key words Dioecious plants, environmental factors, physiology, morphology, sex ratio, stress
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The Effect of Stress on the Pathology of Idiopathic Inflammatory Bowel Disease.
Zacharová, Bianka ; Vodička, Martin (advisor) ; Petr Hermanová, Petra (referee)
Inflammatory bowel disease (IBD), consisting of Crohn's Disease and ulcerative colitis are chronic diseases of the gastrointestinal tract. The incidence of IBD is rapidly rising, most notably in recently industrialized countries. One of the factors contributing to the pathophysiology of these diseases, although often overlooked, is psychological stress. Stress can induce relapses and it can exacerbate IBD through multiple mechanisms affecting the nervous, endocrine, and immune systems. This then results in low-grade inflammation, impaired intestinal epithelial barrier function, and dysbiosis. From the immunological perspective, stress causes mast cell degranulation and shifts in macrophage and T cell differentiation. Both animal models and humans with IBD have significantly altered microbial profiles in their gut, which can be further worsened after undergoing stress. Knowing that brain-gut interactions are bidirectional, IBD is often comorbid with neuropsychiatric disorders, most commonly with depression and anxiety. This phenomenon was observed not only in cohort studies but also in murine models, where colitis is often associated with depressive-like behavior. While the exact mechanism causing the development of these comorbidities is unknown, multiple factors are speculated to play an important...
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The effect of stress on astrocytes and their function during brain development in adolescence
Veverka, Jakub ; Nekovářová, Tereza (advisor) ; Telenský, Petr (referee)
Astrocytes have perhaps been historically underestimated in their number of roles regarding brain homeostasis. Recent studies are identifying the pivotal role they play in brain restructuring and how possible disruption of their function could be a predisposing factor for numerous psychiatric diseases. Proper astrocytic function might be of increased significance in adolescence, when major heterochronic brain restructuring occurs, and external stressors are of magnified effect. Regarding the role of astrocytes in synaptic formation/degradation and synaptic cleft substance clearance, the dysfunction of their homeostatic pathways during such a crucial period may predispose the effected person to specific patterns of CNS development. This could prove to be important during the development or progression of psychiatric and psychological disorders. This work will focus on the role of astrocytes during pathologically stressful conditions, the alteration of their function and the researched causes for such events namely during the unique time period of adolescence. It will also comment on the possible effect of such events during adolescence on the appearance or progression of potential psychiatric or psychological disorders later in life. Key words: Astrocytes, stress, brain, adolescence, development
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Stress-deformation analysis of the high voltage transmission tower
Kuběna, Tomáš ; Pokorný, Jan (referee) ; Fuis, Vladimír (advisor)
The thesis deals with the analysis of a high voltage power pole near the village Lešná, whose collapse will cause an outage of the electricity network in the area. The model of the pole was created on the basis of drawings provided by Arpex Moravia s.r.o. The pole is designed as a truss system using the general node method, subjected to the weight of the structure, wind and the weight of live conductors. The analytical calculation is performed in Matlab and then verified by numerical calculation in Ansys Workbench. When the pole is subjected to all previously mentioned loads, the maximum deformation has a magnitude of u_max=18.89 mm, which is mostly affected by the wind action. The resulting safety to elastic limit state is k_MSP=23.95. The pole is operated with sufficient safety and collapse will not occur under normal operating conditions.
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Strength calculation of high-pressure steam piping according to EN 13480
Řezník, Dominik ; Pernica, Marek (referee) ; Létal, Tomáš (advisor)
The Master's thesis deals with the stress and strength calculation of a high-pressure steam piping system, which is part of the steam piping system of a waste-to-energy plant. In the theoretical part of the thesis, basic knowledge about stress and strength and piping systems (pipe support system, types of loads, fittings and other components) is summarized with respect to the used standards. Part of the theoretical section also includes one of the objectives of the thesis, which is to provide basic knowledge about the KKS codes. In the practical part, firstly, using the VVD software, the pipe class is calculated and created in order to design nominal thicknesses of all the pipes and fittings from the piping system. The core part of the work is the performance of the stress and strength calculation in the CAESAR II software, which includes the appropriate setting of the calculation model based on the calculated pipe class and the documentation from the customer, the selection of pipe supports and the adjustment of the pipelines based on the previous and ongoing results. As part of the calculation, the nozzle loads and support loads are also assessed and verified. In the last part of the work, a simplified FEM calculation of the dump-tube (transition component for steam discharge into the condenser) is performed in PRG NozzlePro software. All the modifications are continuously discussed and the results are then summarized.
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Use of Physiological Data to Analyze and Improve the User Experience
Štefeková, Nina ; Beran, Vítězslav (referee) ; Materna, Zdeněk (advisor)
This thesis is concerned with the research of the physiological symptoms of stress, the design and execution of an experiment that can induce short-term stress. Subsequently, the goal was to create a dataset from the experimentally obtained data and use it to train a machine learning model. Stress detection by such a model can be used to analyze the user experience. The proposed experiment uses a combination of stimuli, consisting of a relaxation part, a Stroop test and a web game that deliberately uses an unfriendly user interface. During it, data was recorded using an Empatica E4 device and then processed by an implemented application into the final dataset. A machine learning model that can detect short-term stress was then trained and evaluated. The KNN algorithm model evaluated by cross-validation achieves an accuracy of 84\% when the subject of the is known prior to the model. For an unknown subject, it is on average 78\%. The thesis provides this model and the resulting dataset, for further use. These results show that short-term stress detection is more challenging without prior knowledge of the subject.
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Stress analysis of the only extant pier of the former Ivančice viaduct
Pelaj, Jakub ; Fuis, Vladimír (referee) ; Vaverka, Jiří (advisor)
The bachelor thesis focuses on the stress analysis of the original Ivančice viadukt pillar. The introductory part describes the theoretical basis necessary for the analysis. The second part deals with the history and assembly of the bridge. The third part dedicates to the creation of three-dimensional structure which serves as a basis for conducting the stress analysis. The following part provides a detailed expanation of the solution process and analytical calculations itself. In the conclusion, the obtained results are verified using numerical calculations a supplement with partial results concerning an additional type of load.
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Analyzing a person’s handwriting for recognizing his/her emotional state
Chudárek, Aleš ; Matoušek, Jiří (referee) ; Malik, Aamir Saeed (advisor)
Rozpoznávání emocí z rukopisu je náročný a interdisciplinární úkol, který může poskytnout vhled do psychologického a emočního stavu pisatele. V této diplomové práci byl vyvinut a vyhodnocen model strojového učení schopný predikovat emoční stav pisatele na základě vzorků jeho rukopisu. Byl využit dataset EMOTHAW, který obsahuje vzorky rukopisu a kreseb od subjektů, jejichž emoční stavy byly změřeny pomocí testu DASS, který hodnotí úroveň deprese, úzkosti a stresu, a CIU Handwritten databázi pro ověření a experimentování. Bylo extrahováno množství příznaků inspirovaných standardní grafologií, stejně jako příznaky specifické pro online data. Pomocí ANOVA byly vybrány statisticky významné příznaky, které byly normalizovány pomocí Z-Score, MinMax, IQR nebo logaritmické transformace. Dimenzionalita příznaků byla snížena pomocí analýzy hlavních komponent (PCA) a lineární diskriminační analýzy (LDA). Pro klasifikaci byl použit meta-přístup Ensemble learning, který se snaží snížit chyby jednoho jednoduchého modelu využitím rozmanitosti a doplňkovosti více modelů. Struktura klasifikátoru závisí na mnoha argumentech, což vede k více než 300 000 různým konfiguracím. Optimální argumenty a tudíž optimální struktura byla hledána pomocí zamrazování argumentů. Byly identifikovány nejlepší klasifikátory pro binární a trinární klasifikaci každé emoce, což vedlo k šesti optimálním modelům. Tyto modely byly hodnoceny pomocí různých metrik, jako jsou accuracy, precision, recall a F1 Skóre, a dosáhly adekvátních výsledků ve všech metrikách. Kromě nalezení klasifikátorů tato práce zkoumala význam každého extrahovaného příznaku, čímž byl vytvořen seznam nejvýznamnějších příznaků použitých pro rozpoznávání emocí z rukopisu. Dále tato práce rozšiřuje databázi EMOTHAW identifikací úkolů, které jsou více indikativní pro specifické emoce, čímž se snižuje potřeba kompletní baterie úkolů pro emoční analýzu.
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Personality Development of the Company Manager
Sekretareva, Sofiia ; Konečná, Zdeňka (referee) ; Pfeifer, Marcel Rolf (advisor)
This bachelor thesis focuses on the analysis of personal development of managers and its impact on the efficiency and success of a company. The theoretical part defines key concepts such as management functions, roles, leadership styles, motivation, time management, and work-life balance. The practical part examines the current state of personal development of managers in the company a questionnaire survey and in-depth interviews. Based on the information obtained, measures are proposed to improve the work environment and support the development of managers, eading to increased efficiency, motivation, and overall success of the company.
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