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The rise of machine learning has seen an increase in digital methods for use within health care. Arrythmia detection is one of the areas where this increase is obvious. However, many machine learning methods for arrythmia detection utilise models that are computationally expensive, such as convolutional neural networks, CNNs. This thesis examines whether it is viable to use the Fast Fourier Transform to transform an Electrocardiogram, ECG, signal into its frequency components before training a neural network, NN, on the data. This could allow for a lower computational cost and wider availability of arrythmia detection technology. The results from the model were compared to that of a CNN trained on time domain data. The results show that the CCN model outperforms the NN trained on FFT transformed data but the performance of the model still indicates that valuable information about heart arrythmias does exist within the frequency space. This suggests a potential for future work on the subject.

Les activités liées au développement d’objets connectés munis d’intelligence embarquée ont connu un essor considérable ces dernières années, en particulier pour les applications médicales. Dans ce contexte, une course effrénée s’est engagée entre les pionniers de l’IoT afin d’offrir des produits toujours plus performants. Smartphones, bracelets ou textile intelligent, tous intègrent un panel de capteurs multifonctionnels. Il est envisageable alors d’implémenter dans ces produits des solutions permettant de mesurer les signaux physiologiques en continu. En effet, ces signaux émis par le corps humain représentent une source riche d’informations que peut exploiter le corps médical pour le diagnostic ou la prévention d’une pathologie. Les maladies cardiovasculaires, étant la première cause de mortalité dans le monde, le diagnostic précoce de ces maladies est important et des solutions peuvent être apportées par les nouvelles technologies. Ainsi, les pathologies liées aux troubles du rythme cardiaque peuvent être décelées par une analyse inter-battements cardiaques en continu. En effet, l’analyse de la variabilité de la fréquence cardiaque représente un indicateur pertinent sur le fonctionnement cardiovasculaire. Or, cette pertinence dépend en grande partie de l’intelligibilité de l’information mesurée. La pertinence des algorithmes utilisés n’ayant pas été étudiée dans la littérature en fonction du niveau de bruit, la détection des battements cardiaques constitue donc un défi de taille lorsque celle-ci est effectuée en environnement non-maitrisé à partir de dispositifs embarqués et ce travail de thèse a essayé d’apporter des réponses concrètes à cette problématique. / Activities related to the development of connected objects with on-board intelligence have undergone considerable growth in recent years, especially for medical applications. In this context, a frantic race has begun between the pioneers of the IoT in order to offer ever moreefficient and intelligent products. Smartphones, wristbands or smart textiles all incorporate a panel of multifunctional sensors. According to the predictions of the Allied Market Research, the annual growth rate for sensors will reach 11.3% by 2022. The vital signs emitted by thehuman body represent a rich source of information that can be exploited by the medical corps for the diagnosis or prevention of a pathology of interest. Cardiovascular disease, being the second cause of death in the world, reminds us of the importance of a rigorous diagnosis.Pathologies related to heart rhythm disorders are generally detected by cardiac cross-heartbeat analysis. The detection of these beats is one of the most important axes of research in the field of electrocardiogram treatment. Indeed, the analysis of heart rate variability is a relevantindicator of cardiovascular functioning. This relevance depends, in large part, on the intelligibility of the measured information and the signal-to-noise ratio of the parameter of interest. The detection of heartbeats is a daunting challenge when it is carried out from onboarddevices especially in noisy environments.

In this diplomat theses are considered the effects of light on human beings, especially on physical performance. The goal of this work was to design a suitable method for evaluation of the effects of light on physical performance. Furthermore, to verify designed methods in laboratory environment and the assessment of collected data. After creating this method several people were tested under different light conditions and collected date evaluated. The results are suggesting that high intensity lighting with low wave lengths leads to an increase of physiological activity in organism and therefore to a potential decreasing physical performance.

We calculate the circularly polarized Stokes V(λ) profile for emission lines, formed in hot-star winds threaded with a weak radial magnetic field. For simplicity, the field is treated as a split monopole under the assumptions that it has been radially combed by the wind, and rotation is not playing a central role. Invoking the weak-field approximation, we find that the V(λ) profile has a characteristic “heartbeat” shape exhibiting multiple sign inversions, which might be mistaken for noise in the absence of theoretical guidance. We also conclude that there is a tendency for the V(λ) profile to integrate to zero on each side of the line separately. The overall scale of V(λ)/I(λ) is set by the ratio of the field strength to the flow speed, B/v, characteristic of the line-forming region, and is of the order of 0.1% for a wind magnetic field B ≅ 100G at depths where the wind speed is v ≅ 100 km s−1.

No description available.

Body ownership is a complicated and multifaceted percept. Although we subjectively perceive body ownership to be a stable component of our identity, recent work has illustrated that body ownership is a dynamic construct that is constantly updated by the integration of current endogenous and exogenous body-related information. The goal of this study was to explore the relation between these endogenous (interoceptive) and exogenous (exteroceptive) channels of information. We investigated this by using a heartbeat perception (HBP) task to measure interoceptive accuracy, and the Rubber Hand Illusion (RHI) to measure malleability of body ownership. Based on prior findings, we hypothesized that the less accurate you are at counting your heartbeats, the more susceptible you will be to the RHI (i.e. the more malleable your sense of body ownership will be). In addition, we were also interested in exploring the relationship between interoception and emotion recognition ability (ERA). In this experiment, we failed to induce the RHI, and thus could not investigate the relationship between endogenous and exogenous body-related information. However, we successfully demonstrated the reliability of the interoceptive accuracy HBP task, as well as demonstrated that interoceptive accuracy is not related to ERA. / Thesis / Master of Science (MSc)

lt;p align="justify"gt; The present work aimed to assess the intensity of effort of the coffee pickers in different stages of the manual coffee picking, by means of the Heartbeat Frequency, Systolic Arterial Pressure and rate pressure-product, during the three stages of the coffee harvest, in the city of Caratinga-MG. 154 workers were selected and assessed, 77 men and 77 women. The sampling consisted of coffee pickers, with ages ranging between 18 to 57. The design of this work took place in four distinguished moments. Firstly, all the farm workers selected were submitted to a top benchmark test, to assess the maximum *VO2 , maximum rate-pressure product of the workers, through the Balke Protocol (MARINS amp; GIANNICHI, 1998). In a second moment, with the maximum *VO2 results available, the farm workers were compared and classified according to the Aerobic Conditioning Classification Chart for men and women. In a third stage, the heartbeat rate, arterial pressure and rate pressure-product were measured during the stages of: cropping, gathering and fanning. In stage four, the values of heartbeat rate, arterial pressure and rate pressure-product obtained in the three stages of the coffee picking were compared by means of statistical analysis, to determine the statistically significant difference of the values of work load. In the VO2max, classification, there can be noticed that 18 men and 26 women, representing 23.37% and 33.77% , respectively, were qualified as GOOD, for the Balke benchmark test; 41 men and 47 women, 53.25% and 61.03%, classified as REGULAR; 16 men (20.78%) and 3 women (3.90%) classified as BAD; and 2 men (2.60%) and 1 woman (1.30%) classified as VERY BAD. There was a significant increase of the heartbeat rate in all three stages of the harvest as related to heartbeat rate when at rest. It was also assessed that the highest mean values, for both genders, was during the Gathering stage (115.2bpm for the men and 105.3bpm for the women), followed by the Fanning (105.6bpm for the men and 108bpm for the women) and Dropping 91.8bpm for the men and 105.3 for the women), respectively. The mean values found for the heartbeat rates characterize the stages of dropping and fanning of the coffee as reasonably mild, for both the genders, with relative values from 50.28% to 60.81% for the Max. heartbeat rate or 28% to 40% of the VO2max. The values found in the gathering stage, of 63.09% of the max. heartbeat rate for the men, classifies this stage as Reasonably Mild; for the women, the percentage of 69.36 max Heartbeat rate classifies this stage as Rather Hard. The gathering stage recorded the highest mean values of arterial pressure for both the genders (137.40mm Hg for the men and 137.79mm Hg for the women), followed by Fanning (132.68mm Hg foe the men and 134.63mm Hg for the women) and Dropping (129.87 mm Hg for the men and 128.87mm Hg for the women), respectively. In the stages of Dropping and Gathering there was no Significant Difference in the results, regarding genders. The highest mean vales of rate pressure-product found in the three stages of the coffee harvesting were, respectively: 15836.58 for the men, and 16995.06 for the women in the Gathering stage; 14000.43 for the men and 14563.8 for the women in the Fanning; and 11944.3 for the men and 13574.3 for the women in the Dropping stage.lt;/pgt; / lt;p align="justify"gt; O presente trabalho teve como objetivo avaliar a intensidade de esforço dos colheitadores de café, através da Freqüência Cardíaca, Pressão Arterial Sistólica e Duplo Produto, durante as três etapas da colheita do café, no município de Caratinga – MG. Foram selecionados e avaliados 154 trabalhadores, sendo 77 do sexo masculino e 77 do sexo feminino. A amostra foi de colheitadores de café, na faixa etária entre 18 e 57 anos de idade. O processo de construção deste trabalho ocorreu em quatro (04) momentos distintos. No primeiro momento, todos os trabalhadores rurais selecionados foram submetidos a um teste máximo de banco, para estimar o de VO2max. e o duplo produto máx., através do Protocolo de Balke (MARINS amp; GIANNICHI, 1998). No segundo momento, com resultados do teste VO2max., os trabalhadores rurais foram comparados e classificados de acordo com a Tabela de Classificação do Condicionamento Aeróbio de Homens e Mulheres. No terceiro momento, foi avaliada a freqüência cardíaca, a pressão arterial e o duplo produto dos trabalhadores rurais durante as etapas de: derriça, recolhimento e abanação. No quarto momento, os valores de freqüência cardíaca, pressão arterial e duplo produto, obtidos nas etapas da colheita, foram comparados através da análise estatística, para determinar as diferenças significativas dos valores da carga de trabalho. Na classificação do VO2max, pode-se observar que 18 homens e 26 mulheres, que representam 23,37% e 33,77%, respectivamente, foram classificados como BOM, no teste de banco de Balke; 41 homens e 47 mulheres, 53,25% e 61,03%, classificados como REGULAR; 16 homens (20,78%) e 03 mulheres (3,90%), classificados como RUIM; e 02 homens (2,60%) e 01 mulher (1,30%) classificados como MUITO RUIM. Observaram-se maiores valores médios, em ambos os sexos, na etapa de Recolhimento (115,2 bpm para os homens e, 123,2 bpm para as mulheres), seguido pela Abanação (105,6 bpm para os homens e, 108 bpm para as mulheres) e Derriça (91,8 bpm para os homens e, 105,3 bpm para as mulheres), respectivamente. Os valores médios de freqüência cardíaca encontrados caracterizam as etapas de derriça e abanação de café como Razoavelmente Leve, para ambos os sexos, com valores relativos entre 50,28% a 60,81% da FCmáx ou 28% a 40% do VO2 máx. Os valores encontrados na etapa de recolhimento, de 63,09% da FCmáx para os homens, classifica a etapa como Razoavelmente Leve; para as mulheres, o percentual de 69,36% da Fcmáx, classifica a etapa como Bastante Dura. Foram observados maiores valores médios de Pressão Arterial, em ambos os sexos, na etapa de Recolhimento (137,40 mm Hg para os homens e, 137,79 mm Hg para as mulheres), seguido pela Abanação (132,68 mm Hg para os homens e, 134,63 mm Hg para as mulheres) e Derriça (129,87 mm Hg para os homens e, 128,87 mm Hg para as mulheres), respectivamente. Nas etapas de Derriça e Recolhimento não houve diferença significativa nos resultados, em relação ao sexo. Os maiores valores médios de DP encontrados nas três etapas da colheita de café foram, respectivamente: na etapa Recolhimento, 15836,58 para os homens e 16995,06 para as mulheres; na etapa Abanação, 14000,43 para os homens e 14563,8 para as mulheres; na etapa Derriça, 11944,3 para os homens e 13574,3 para as mulheres.lt;/pgt;

Left ventricular (LV) volumes and ejection fraction (EF) are important predictors of cardiac morbidity and mortality. LV volumes provide valuable prognostic information which isparticularly useful in the selection of therapy or determination of the optimal time for surgery. Two-dimensional (2D) echocardiography is the most widely used non-invasive method forassessment of cardiac function, 2D echocardiography has however several limitations inmeasuring LV volumes and EF since the formulas for quantifications are based on geometricalassumptions. Three-dimensional (3D) echocardiography has been available for almost twodecades, although the use of this modality has not gained wide spread acceptance. 3D echocardiography can overcome the above mentioned limitation in LV volume and EF evaluation since it is not based on geometrical assumption. 3D echocardiography has been shownin several studies to be more accurate and reproducible with low inter- and intraobservervariability in comparison to 2D echocardiography regarding the measurements of LV volumesand EF. The overall aim of the thesis was to evaluate the feasibility and accuracy of 3D echocardiography based-methods in the clinical context. In Study I the feasibility of 3D echocardiography was investigated for determination of LV volumes and EF using parasternal, apical and subcostal approaches. The study demonstrated that the apical 3D echocardiography view offers superior visualization. Study II tested the possibility of creating flow-volume loops to differentiate patients with valvular abnormalities from normal subjects. There were significant differences in the pattern from flow-volume loops clearly separating the groups. In Study III the visual estimation, “eyeballing” of EF was evaluated with two- and tri-plane echocardiography in comparison to quantitative 3D echocardiography. The study confirmed that an experienced echocardiographer can, with a high level of agreement estimate EF both with two- and tri-plane echocardiography. Study IV exposed the high accuracy of stroke volume and cardiac output determination using a3D biplane technique by planimetrically tracing the left ventricular outflow tract and indicating that an assumption of circular left ventricular outflow tract is not reliable. In Study V, two 3D echocardiography modalities, single-beat and four-beat ECG-gated 3D echocardiography were evaluated in patients having sinus rhythm and atrial fibrillation. Thesingle-beat technique showed significantly lower inter-and intraobserver variability in LV volumes and EF measurements in patients having atrial fibrillation in comparison to four-beat ECG-gated acquisition due to absence of stitching artifact. All studies demonstrated good results suggesting 3D echocardiography to be a feasible andaccurate method in daily clinical settings. / degree of Medical DoctorQC 20100629

Neuroprosthetics is at the intersection of neuroscience, biomedical engineering, and physics. A biocompatible neuroprosthesis contains artificial neurons exhibiting biophysically plausible dynamics. Hybrid systems analysis could be used to prototype such artificial neurons. Biohybrid systems are composed of artificial and living neurons coupled via real-time computing and dynamic clamp. Model neurons must be thoroughly tested before coupled with a living cell. We use bifurcation theory to identify hazardous regimes of activity that may compromise biocompatibility and to identify control strategies for regimes of activity desirable for functional behavior. We construct real-time artificial neurons for the analysis of hybrid systems and demonstrate a mechanism through which an artificial neuron could maintain duty cycle independent of variations in period.