National Repository of Grey Literature 491 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
One-trial association task as a basic biological model of episodic memory in rats
Radostová, Dominika ; Stuchlík, Aleš (advisor) ; Horáček, Jiří (referee) ; Telenský, Petr (referee)
One-trial association task as a basic biological model of episodic memory in rats Abstract A very important structure in the animal and human brain is the hippocampus. The study one of its many functions, episodic memory, is facing with the limited possibilities of non-invasive methods. In this regard, animal models are helpful. In order to study the individual components of such a complex ability in detail, a new behavioral task testing the association of temporally close but separate stimuli was developed. The test animals were exposed to a sequence of a sound conditioned stimulus and an unconditioned electric shock, between which there was a delay of 2 seconds. 59% of the rats successfully learned the association as well as the correct escape reaction to solve the task. Based on the results, the so-called One-Trial Trace Escape Reaction task could be a very valuable tool for a more detailed understanding of animals' incidental one-trial learning important for episodic memory. Another important phenomenon investigated in this work is the development of new neurons in the hippocampus in adulthood and its influence on learning and flexibility. After blocking the animals' neurogenesis with the temozolomide, the animals' ability to learn to avoid an invisible sector in the active avoidance task was tested....
Finite element modal analysis of a silicone vocal fold filled with fluid
Hájek, P. ; Radolf, Vojtěch ; Horáček, Jaromír ; Švec, J. G.
A three dimensional (3D) finite element (FE) model of a silicone vocal fold (VF) filled with fluid is presented here. The silicone part of the model is based on partial differential equations of the continuum mechanics and consider large deformations. The fluid domain encapsulated in the silicone VF is defined semianalytically as a lumped-element model describing the fluid in hydrostatic conditions. The elongated and pressurized silicone VF was subjected to perturbed modal analysis. Results showed that the choice of the fluid inside the VF substantially influences the natural frequencies. Namely, the water-filling lowers the natural frequencies approximately by half over the air-filling. Besides, the procedure of reverse engineering for obtaining the geometry of the VF from already 3D-printed mold is introduced.
Prediction of the Antidepressant Effect of Ketamine Based on Clinical Parameters and Intoxication Phenomenology
Andrashko, Veronika ; Horáček, Jiří (advisor) ; Papežová, Hana (referee) ; Juřica, Jan (referee)
Background: ketamine is a rapid and potent antidepressant treatment, however no sufficient predictors for tailored treatment have been identified to date. The aim of the thesis was to identify possible clinical and phenomenological characteristics, associated with better antidepressant response in patients receiving ketamine. Materials and methods: data from 86 depressed patients from cohorts A (2010-2015) and B (2018-2022) were utilized. All patients underwent ketamine infusion and demographic as well as clinical assessment (severity of depressive symptoms, subjective and objective anxiety and anhedonia before and after ketamine application). In addition, an electrocardiogram was taken to assess heart rate variability in cohort A and blood pressure, heart rate, and altered state of consciousness scales were recorded in cohort B during ketamine intoxication. Results: in cohort A, the use of higher doses of benzodiazepines was associated with worse response at day 3 (p = 0.04) and day 7 (p = 0.02) after ketamine administration. Responders showed higher heart rate (p = 0.001) and differed from nonresponders in heart rate variability (p = 0.011). In cohort B, responders reached higher values od systolic (p = 0.003) and diastolic (p = 0.005) blood pressure during intoxication, but not higher heart...
Altered morphology of white and grey matter in patients with Alzheimer disease and Schizophrenia on MRI
Lahutsina, Anastasiya ; Zach, Petr (advisor) ; Horáček, Jiří (referee) ; Němcová, Veronika (referee)
Cortical folding of the anterior cingulate cortex (ACC), particularly the cingulate (CS) and the paracingulate (PCS) sulci, represents a neurodevelopmental marker. Deviations in in utero development in schizophrenia can be traced using CS and PCS morphometry. In the present study, we measured the length of CS, PCS, and their segments on T1 MRI scans in 93 patients with first episode schizophrenia and 42 healthy controls. Besides the length, the frequency and the left-right asymmetry of CS/PCS were compared in patients and controls. Distribution of the CS and PCS morphotypes in patients was different from controls. Parcellated sulcal pattern CS3a in the left hemisphere was longer in patients (53.8 ± 25.7 mm vs. 32.7 ± 19.4 mm in controls, p < 0.05), while in CS3c it was reversed-longer in controls (52.5 ± 22.5 mm as opposed to 36.2 ± 12.9 mm, n.s. in patients). Non parcellated PCS in the right hemisphere were longer in patients compared to controls (19.4 ± 10.2 mm vs. 12.1 ± 12.4 mm, p < 0.001). Therefore, concurrent presence of PCS1 and CS1 in the left hemisphere and to some extent in the right hemisphere may be suggestive of a higher probability of schizophrenia. Measurement of an hippocampal area or volume is useful in clinical practice as a supportive aid for diagnosis of Alzheimer's disease....
Robust semi-generalized camera pose estimation using multiple minimal solvers
Beliansky, Patrik ; Kúkelová, Zuzana (advisor) ; Horáček, Jan (referee)
Camera pose estimation is a fundamental problem in computer vision with various ap- plications, such as in Structure-from-Motion and Visual Localization. These applications often focus on registering a new camera to a set of already registered cameras with known poses. Thus, camera poses can be estimated by solving the semi-generalized relative pose problem. This is usually achieved by using a minimal solver inside a RANSAC-style robust estimator. This estimator can handle data with a large amount of outliers. While solvers for the semi-generalized relative pose problem are typically too inefficient for practical use, the highly related semi-generalized homography problem can be solved effi- ciently. This thesis develops and investigates different implementations, e.g., using Sturm sequences or companion matrix approaches, for multiple solvers for this problem. This thesis further proposes a novel RANSAC-based approach that automatically selects the most suitable solver for each iteration in a data-driven way. In detailed experiments, the solvers are evaluated in terms of efficiency and stability. Extensive experiments show the effectiveness of our novel RANSAC-based approach by comparing it against two baselines. 1
Automation of nuclear fuel visual inspection
Knotek, Jaroslav ; Blažek, Jan (advisor) ; Horáček, Jan (referee)
The safety and performance of nuclear plant relies, among others, on the quality of nuclear fuel. The quality fulfilling designed criteria of the fuel in use is inspected and reported on periodically. Visual inspection focuses on the condition of the fuel based on its visual properties. During the inspection, the fuel is being recorded and analysed by the inspector. The current state of the fuel assemblies is compared to the historical statistics which helps do decide whether this particular assembly remains or gets replaced. This thesis describe a project initiated by Centrum Výzkumu Řež focusing on digital image processing methods application to visual inspection process. The result of the project is a tool that accelerates the process of report making. Firstly, it transforms the inspection video into one image overview and highlight a significant part (more than 95%) of possible defects to the inspector. 1
The influence of morphometric changes of gray and white matter on brain functional connectivity in schizophrenia
Görnerová, Natálie ; Horáček, Jiří (advisor) ; Zach, Petr (referee) ; Filip, Pavel (referee)
More than a century has passed since a clear definition for schizophrenia was established, yet, the etiology, neuropathological and pathophysiological mechanisms of this psychiatric disorder still, to a large extent, remain to be elucidated. In the theoretical part of this dissertation, we review current classification and pathophysiology of schizophrenia, paying a particular attention to the findings from structural and functional imaging techniques. These techniques demonstrate that patients with schizophrenia tend to have reduced volume of grey matter, reduced integrity of white matter and a disrupted inter-regional functional connectivity (FC). The temporal association between structural changes, already detectable on imaging before symptoms appear, and development of disrupted FC remains to be uncovered. At the same time, current knowledge does not fully explain the link between disrupted FC and disturbed experience of self-awareness, a core symptom of schizophrenia. In addition, it is necessary to develop novel effective methods to prevent relapse and prevent the progression of neurobiological changes in the brain. In the practical part of this dissertation, we designed a study with three different groups of subjects aiming to fulfil three key aims that would help us to fill the gaps in...
Damping of human vocal folds vibration
Radolf, Vojtěch ; Horáček, Jaromír ; Bula, Vítězslav ; Geneid, A. ; Laukkanen, A. M.
This study investigates the biomechanics of the end-part of phonation, i.e. the so-called phonation offset, experimentally. This information of vocal fold damping is important for testing and further development of mathematical modelling of phonation. The measurements of the damping ratio, based on high-speed videolaryngoscopic registrations, were realized on a male subject phonating on the vowel [o:]. The results show during the phonation offset a remarkable decrease of vibration frequency of the vocal folds and an increased damping ratio limiting to the value D≈ 0.2. The results for vocal folds’ damping are in agreement with previous measurements performed on humans using different methods.
Accelerating cross-correlation with GPUs
Maděra, Karel ; Kruliš, Martin (advisor) ; Horáček, Jan (referee)
Cross-correlation is a commonly used tool in the field of signal processing, with ap- plications in pattern recognition, particle physics, electron tomography, and many other areas. For many of these applications, it is often the limiting factor on system perfor- mance due to its computational complexity. In this thesis, we analyze the cross-correlation algorithm and its optimization and parallelization possibilities. We then implement sev- eral optimizations of the definition-based algorithm, mainly focused on parallelization using the Graphical processing unit (GPU). Even though the definition-based algorithm provides many possibilities for parallelization, the implementation needs to solve several problems, such as the algorithm's low arithmetic intensity. Furthermore, the problems differ between computation types, which include cross-correlating a pair of inputs, one in- put with many other inputs, or many inputs with many other inputs. Lastly, we compare the optimizations of the definition-based algorithm with the asymptotically faster and commonly used algorithm based on the Fast Fourier Transform. Depending on the total size of the data, we achieve parity between the two algorithms for matrix sizes ranging from 60x60 to 150x150, allowing performance improvements for systems using matrices smaller...

National Repository of Grey Literature : 491 records found   1 - 10nextend  jump to record:
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