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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Klasifikace srdečních cyklů / Heart beat classification

Potočňák, Tomáš January 2013 (has links)
The aim of this work was to develop the method for classification of ECG beats into two classes, namely ischemic and non-ischemic beats. Heart beats (P-QRS-T cycles) selected from animals orthogonal ECGs were preprocessed and used as the input signals. Spectral features vectors (values of cross spectral coherency), principal component and HRV parameters were derived from the beats. The beats were classified using feedforward multilayer neural network designed in Matlab. Classification performance reached the value approx. from 87,2 to 100%. Presented results can be suitable in future studies aimed at automatic classification of ECG.
152

Analýza zatížení hráčů golfu / Load analysis of golf players

Kunčická, Zlata January 2017 (has links)
Title: Load analysis of golf players Objectives: The aim of the study was to determine the load intensity of golf players, the comparison between players of different levels and determine the health benefits of the game. Methods: The theoretical part was processed thorough a study of scientific literature. Data were measured by sport-tester Garmin, which were then processed in the Garmin Connect and in Microsoft Excel. Was determined by calculating the maximum heart rate of the individual player and the results were compared qualitatively and quantitatively with the scientific literature. Results: Golf is a light to moderate aktivity of load amounting 62% of the maximum heart rate of the individual. Golf in conjunction with the movement on the field can have a positive effect on humans and prevent lifestyle diseases associated with hyperkinesis. During one eighteen-round of golf player conquers average of 10.5 km and reforge as 70% of the official length of the course. Professional players spend more time reading the terrain and planning launch, so they are moving more. Keywords: golf, heart beat, health, condition, golf field
153

Assembly and composition of the cECM is critical for heart physiology

Lammers, Kay 12 April 2022 (has links)
The present study focuses on the cardiac function of Drosophila melanogaster. Drosophila heart parameters are evolutionarily conserved, making Drosophila a useful human heart disease model. This model enables the in vivo investigation of physiological and genetic methods. This thesis is subdivided into four parts: parts 1-3 comprise the introductions of three publications, and part 4 presents unpublished data. The first publication is about the heart physiology of Drosophila. It explains how intracardiac valve cells work and proves their participation in blood flow directionality. A databased model shows the orientation of myofibrils within the valve cell. The myofibrils allow the valve cells to oscillate between a roundish and elongated cell shape. A toll-GFP enhancer line was shown to mediate strong reporter gene activity in the intracardiac valve of third instar larvae, pupae and adults. Transmission electron microscopy (TEM) analyses and immunohistochemical studies showed the differentiation of larval valve cells for the first time. The second publication focuses on the cardiac extracellular matrix (ECM), which contains two unique proteins - Lonely heart (Loh) and Pericardin (Prc). The study demonstrated that Loh is crucial for Prc recruitment to the developing matrix. Loh is anchored to the ECM by its thrombospondin type 1 repeat (TSR1-1) with its embedded putative glycosaminoglycan (GAG)-binding side. The N-terminus of Loh is proposed to face the plasma membrane. Prc is presumably recruited by two Loh TSR1 domains (TSR1-2 and TSR1-4). Nearly all Drosophila tissues, except salivary glands, create Prc networks through ectopic Loh expression. The study also found that the amount of Prc and Loh in the cardiac ECM influences heart function. The third publication investigated a set of neuropeptides and their ability to modulate cardiac function in third instar larvae. The results showed that 11 of the 19 tested peptides significantly affected the heart function in semi-intact larvae. Furthermore, the peptides’ in vivo relevance was tested through the knockdown of chronotropic peptide precursors. The study found that a RNAi mediated knockdown of all respective peptide precursors affected the heart rate. By combining semi-intact heart preparations and in vivo analyses, we identified several heartbeat-modulatory peptides in Drosophila. The unpublished data introduces a new software program called HIRO. It is written in Java, platform-independent and can easily detect the heart rhythm. Only mild anaesthesia and basic equipment are needed to record the Drosophila heartbeat. HIRO was used to show the influence of the RNAi-mediated downregulation of critical ECM proteins in Drosophila third instar larvae. The screen revealed Myospheroid and Laminin A as promising candidates that can significantly affect the heart parameters. HIRO is optimised for future applications and can be used as a high-throughput screening software with a simple setup. Taken together, this thesis provides new insights into the physiology and function of the Drosophila heart. The developed software HIRO comes with a user-friendly interface and a step-by-step introduction to easily conduct heart parameter measurements. HIRO will help to expand our knowledge of the fundamental processes in the model organism Drosophila melanogaster.
154

Behavioral state dependent perceptual decision making

Narasimhan, Shreya January 2022 (has links)
The overarching purpose of this work is to investigate the effect of pupil-linked arousal systems and heart rate-linked arousal systems on behavior and the use of pupil dynamics as an index for adaptive behavior. These arousal systems are correlated with behavior states which have modulatory effects on perception and neural coding and are therefore integral in carrying out complex behaviors, such as decision-making. Additionally, cholinergic transmission is proposed to be critical for adaptive behavior via its modulation of thalamic neurons. While the first two chapters focus on the behavior output and the non-invasive ways to index arousal and behavior, the third aim attempts to investigate the neural circuits that underlie arousal’s effect on adaptive behavior by studying the pattern of cholinergic axons between brainstem nuclei and the thalamus, opening avenues for future investigation of their mechanistic impact on adaptive behavior. For characterization of the influence of arousal indexed by pupil dynamics and heartbeat dynamics, we simultaneously recorded electrocardiogram (ECG) and pupil size in head-fixed rats performing tactile discrimination tasks. We found both heartbeat dynamics and pupil size co-varied with behavioral outcomes, indicating behavior was dependent upon arousal indexed by both physiological signals. The potential difference between the effects of pupil-linked arousal and heart-rate linked arousal on behavior were estimated by constructing a Bayesian decoder predicting animals’ behavior from both signals prior to stimulus presentation. The decoder performed significantly better when using both physiological signals as inputs, suggesting both arousal systems, pupil-linked and heart rate-linked are not completely redundant. Additionally, the pupil size-based decoder failed to correctly predict animals’ behavior on a substantial portion of trials correctly predicted by the heart rate-based decoder, furthermore suggesting that both arousal systems exert different influences on animals’ behavior (Y.Liu, S. Narasimhan, B.J.Schriver, & Q.Wang, 2021). For characterization of how adaptive behavior in response to changing sensory environments depends on pupil-linked arousal, we recorded pupil size and behavioral output simultaneously during a similar tactile Go/No-Go discrimination task while systematically varying the statistics of the sensory environment. For each session, the probability of the presence of reward linked-stimuli (S+/Go) was randomly set at 80%, 50% or 20%. Animals adapted their behavioral responses and the task evoked pupil responses were bigger when the probability of S+ was lower. Impulsive licking (pre-stimulus response) decreased as the probability of S+ was lower. Animals became more liberal as the probability of S+ increased, in line with signal detection theory, indexed by a decrease in the decision criterion. We additionally found that reaction time decreased as the probability of S+ increased. A hierarchical drift diffusion model (HDDM) was used to model the decision-making process in these paradigms. We found the drift rate to monotonically vary with task difficulty. Animals performed sub-optimally to adaptively change their action in response to changes in the sensory environment and this adaptive adjustment in decision-making was indexed by their pupil dynamics. For studying the pattern of cholinergic axons between brainstem nuclei and the thalamus, we used two different AAV-retrograde constructs with two different reporters (mCherry and GFP) injected in the left and right hemisphere of the ventral-posterior-medial (VPM) thalamic nucleus of recombinant ChAT-cre mice. In agreement with previous studies done with conventional tracing methods, labelled projecting cells were traced to the LDT and PPN in the brainstem. Labelled cells were found in a clustered area of the LDT, suggesting a topographic distribution of the projections between the LDT and the VPM. A larger quantity of labelled cells was found in the PPN than the LDT. Additionally, bilateral injections with double reporters enabled us to find that a majority of cells project from the brainstem to the VPM project ipsilaterally while still displaying lateralization. This work provides methods and tools for future investigation of the functional impact of these projections between LDT, PPN and the VPM.
155

Heart Rate and Accelerometry during Singles Footbag Net Play

Siebert, Christopher Michael 01 January 2012 (has links)
This investigation examined the heart rate responses and movement characteristics of experienced footbag net players during singles play. Footbag net is a net/court sport similar to volleyball, but it is played with a footbag (e.g., Hacky-SackTM) using only the feet. In singles footbag net, players are allowed either one or two kicks to propel the footbag over the net. Subjects were 15 males and 1 female, ranging in age from 18- 60 years, with a mean age of 33.6 years. Subjects played two games of singles footbag net using two different scoring systems: "sideout" scoring and "rally" scoring. Mean heart rates were 149.4 bpm for games played under the sideout scoring system and 148.7 bpm for games played under the rally scoring system. Sideout games were 1.2 minutes (~11%) longer than rally games. The mean heart rate responses to competitive play using sideout scoring and rally scoring were not significantly different (p>0.05). For play under both scoring systems, the average exercise intensity--expressed as a percentage of age-predicted maximum heart rate (MHRest)--was 80-81% MHRest. Accelerometer counts accumulated during play were similar for both scoring systems. It is recommended that additional research be conducted to evaluate the extent to which accelerometry may contribute to physiological and metabolic measurements of footbag net competition.
156

Detection threshold for heart rate change in psychopaths, recidivists and normals

Volner, William K., Jr. 01 January 1971 (has links)
To test this a three part study would be required. First, it should be determined if there is a difference between the threshold for perception of increased heart rate in psychopaths and normals in order to see if the problem is an attentional one. If such a difference were not found the next step would be to compare psychopaths and normals on the strength of the cognitive fear reaction to Sarm the source of which in this case is increased heart rate. Finally, if results show no cognitive fear attached to the awareness of their increased heart rate, an attempt would be made to condition fear to the physiological stimulus of increased heart rate. The following study was concerned with completion of the initial phase of this three part study.
157

Genetic and environmental influences on heart rate and cardiac-related autonomic activity in five-month-old twins

Dubreuil, Etienne January 2002 (has links)
No description available.
158

A comparison of normal and moderately mentally retarded children aged 7 & 8 on three submaximal cardiovascular endurance tests /

Newlin, Yvette Peck January 1986 (has links)
No description available.
159

Physiological responses, perceptual responses and target heart rate compliance of coronary heart disease patients during walk-jog exercise

Bailey, Barry D. January 1987 (has links)
Nine male CHD patients volunteered for testing to determine variations in heart rate response (HR), walk-jog velocity (W) and compliance to the target heart rate zone under three monitoring conditions. Determination of variations in W, peripheral perceived exertion (RPE<sub>L</sub>) chest perceived exertion (RPE<sub>C</sub>) and post-exercise lactate accumulation (La) during exercise which was held constant between 60-80% maximum HR reserve were also made. Procedures consisted of three 20 min walk-jog exercise conditions. First, two baseline condition (BC) trials were performed on separate days with exercise intensity regulated through intermittent defibrillator-ECG HR checks and radial/carotid artery palpation. Next, continuous telemetry monitoring of HR by staff was added during a single exercise trial (TC). Finally, two Exersentry<sub>R</sub>condition (EC) trials were performed on separate days with continuous feedback concerning HR response provided to the patient via Exersentry<sub>R</sub> devices. Evaluation of HR and W revealed no significant variation between conditions. However, % target HR reserve attained was significantly (p>0.05) lower during early and late BC, as compared to TC. Furthermore, "frequency in" vs "frequency out" of target HR zone was significantly (p>0.05) greater during EC, as compared to TC. During EC, no significant variations in HR, W, La, RPE<sub>L</sub> and RPE<sub>C</sub> were noted. Correlation coefficient values between 0.76-0.95 and 0.58-0.80 were reported for RPE<sub>L</sub> and RPE<sub>C</sub>, respectively. This data suggested that continuous feedback concerning HR response resulted in the greatest compliance to the target HR zone. With the exception of the first five min of EC, only RPE<sub>L</sub> reliably mirrored HR and W. Index terms: Intermittent heart rate monitoring, continuous heart rate monitoring, heart rate response, walk-jog velocity, target heart rate compliance, peripheral perceived exertion, chest perceived exertion, post-exercise lactate accumulation. / M.S.
160

Effects of Age, Fitness Level, and Exercise Training upon Autonomic Control of Heart Rate

Baun, William Boyd 05 1900 (has links)
In this study the effects of age (18-55 years), differing levels of fitness (VO 2max ranging from 35.5 to 68.8ml.kg-1.min-1) and endurance training (10 weeks) on heart rate control were investigated. Fitness level was initially determined by a VO2max stress test, succeeded by cold hand and cold face pressor test of autonomic activity. Following these baseline measurements, the subjects (32 nonsmoking male volunteers) were endurance-trained three to four times a week for a 10-week period. The baseline tests were readministered following the 10-week dynamic exercise training period. These data suggest that a natural consequence of aging is a diminishment of autonomic heart rate control; however, endurance training appears to interrupt the aging influence. Individuals of low fitness level appear to have heart rate control dominated by the sympathetic system, while individuals with high fitness levels have a vagally dominated heart rate control system.

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