The objective of this study was to uncover molecular and cellular dynamics in spermatozoa from Holstein bulls with Good (11 bulls) and Poor (5 bulls) cryotolerance. Post-thaw sperm kinetics, membrane integrity, and DNA fragmentation were assessed. Data was analyzed using principal component analysis. The spermatozoa from Good bulls had a higher number of cells with intact membranes (P = 0.029), nonragmented DNA (P = 0.018), post-thaw viability (P < 0.001) in comparison to those of the Poor bulls. The Good bulls also had a faster average path velocity (VAP; P = 0.017), straight-line velocity (VSL; P = 0.036), a greater distance average path (DAP; P = 0.006) and distance straight line (DSL; P = 0.011). No differences were found in total antioxidant capacity (TAC), number of live cells or other kinetic parameters between spermatozoa from Good and Poor groups, showing that no one characteristic can be used to determine cryotolerance.

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<p> The estimation of physiological parameters that characterize electrical signal propagation in the heart is an important component of the inverse problem in electrocardiography. Recent studies show that some patterns in cardiac electrical signals (e.g. spiral waves) are associated with the re-entrance phenomenon seen in cardiac arrhythmia. Therefore, further research in this field will lead to improved detection and diagnosis of cardiac diseases and conditions. </p> <p> Electrical activity in the heart is initiated at the SA node and an electrical impulse propagates to the atria causing their mechanical contraction. Subsequent contraction of the ventricles (systole) followed by relaxation (diastole) completes the heart cycle. Evidence of electrical activity in cardiac cells is shown by a potential difference across the cell membrane that changes when ·ionic currents flow through the membrane's channels. This electrical activation of the heart can be modeled using a diffusion model in which the physiological parameters (e.g., conductivity) govern the resulting spatiatemporal process. </p> <p> In this thesis we derive an inverse model for the electrical activation of the heart using the Fitzhugh-N agumo diffusion equations which account for the dynamics of spiral waves in excitable media such as, in our case, cardiac cells. The electric potential is expressed through activator and inhibitor variables and we simulate the measurements of the electromagnetic field are on the torso surface. A signal processing model is derived where the physiological parameters are deterministic or stochastic, and the resulting physiological measurements are a function of space, time, and the parameters. </p> <p> We estimate these unknown parameters using an optimization algorithm that minimizes the cost function of the model. For our estimation we use Least Squares and we derive the Maximum Likelihood Estimator. We measure the performance using mean square error, and we compute the Cramer-Rao Lower Bound, which shows the minimum variance attainable. </p> <p> In our simulations we use a finite element mesh of a human torso to describe a realistic geometry to generate the potentials on the surface. Our results indicate that estimating the physiological parameters of a diffusion equation from the measurements taken outside the torso are feasible. This further suggests that ECG/MCG signals can be used to provide detailed information about the physiological properties of the electrical impulse generated in the heart and aid in diagnosis of various pathological conditions including arrhythmia. </p> / Thesis / Master of Applied Science (MASc)

<p> This project will examine the effect of process parameters on the properties of a semi-crystalline cast film. The objective was to conduct the experiment on a commercial scale extruder. The process parameters studied were the chill roll temperature, annealing roll temperature, film thickness and line speed. The intent of this project was not to develop a deterministic model for the casting process, but only to investigate the effect of process parameters on the properties of cast films manufactured on a commercial extrusion line. </p> <p> The film properties evaluated were the tensile strength at break, Young's modulus, elongation at break, and haze. Only the properties in the machine direction (MD) were evaluated. The experimental data was first analyzed by plotting the average film properties against the average normalized process parameters. A second analysis was done with the experimental data by using multivariate data analysis (MVDA). Two multivariate data analysis (MVDA) projected methods were used, these were the partial projection to latent structure (PLS) by means of partial least squares, and the principal component analysis (PCA). The results from the first and second analysis showed that the changes in process parameters affected the properties of the cast films. It is conjectured that the effect of process parameters on semi-crystalline cast film properties are related to the percentage of crystallinity and crystal size. The manipulation of process parameters would change the percentage of crystallinity and crystal size, which in turn modify the properties of cast film. </p> / Thesis / Master of Engineering (ME)

Existing microstructure parameters of computed tomography (CT) are able to compute architectural properties of the bone from ex-situ and ex-vivo scans while they are highly affected by the issues of noise and low resolution when applied to clinical in-vivo imaging. A set of improvements of the standard workflow for the quantitative computation of micro-structure from clinical in-vivo scans is proposed in this thesis. Robust methods are proposed (1) for the calibration of density values, (2) the binarization into bone and marrow phase, (3) fuzzy skeletonization and (4) the calibration of the CT volumes in particular for the computation of micro-structural parameters. Furthermore, novel algorithms for the computation of rod-volume fraction with 3D rose diagrams and fractal approaches are proposed and the application of local texture operators to diffusion tensor imaging is proposed. Finally an existing computer program for the application in radiology departments, Structural Insight, was improved and largely extended. In particular the methods of the microstructural calibration, the fractal and the texture operators showed significant improvements of accuracy and precision for the prediction of fracture risk and the quantitative assessment of the progress of Alzheimer's disease, in comparison to existing state-of-the art methods. The methods were tested on artificial and in-vitro data and as well on real-world computed tomography and magnetic resonance imaging (MRI) studies. The proposed novel methods improve the computation of bone characteristics from in-vivo CT and MRI in particular if the methods are combined with each other. In consequence, this allows to assess more information from existing data or to conduct studies with less ray exposure and regarding the MRI method in shorter time than nowadays required.

Evaluation is the key to effective interface design. It becomes even more important when the interfaces are for cutting edge technology, in application areas that are new and with little prior design knowledge. Knowing how to evaluate new interfaces can decrease development effort and increase the returns on resources spent on formative evaluation. The problem is that there are few, if any, readily available evaluation tools for these new interfaces. This work focuses on the creation and testing of a new set of heuristics that are tailored to the large screen information exhibit (LSIE) system class. This new set is created through a structured process that relies upon critical parameters associated with the notification systems design space. By inspecting example systems, performing claims analysis, categorizing claims, extracting design knowledge, and finally synthesizing heuristics; we have created a usable set of heuristics that is better equipped for supporting formative evaluation. Contributions of this work include: a structured heuristic creation process based on critical parameters, a new set of heuristics tailored to the LSIE system class, reusable design knowledge in the form of claims and high level design issues, and a new usability evaluation method comparison test. These contributions result from the creation of the heuristics and two studies that illustrate the usability and utility of the new heuristics. / Ph. D.

The objective of the present study was to understand how the visual and mental processes work in tandem to affect the overall information processing capability of the individual, especially the older population, in a dynamic visual task such as driving. More specifically, our aim was to understand how the different parameters related to display of visual information in an in-vehicle display system and the age of the subject affect the information processing performance. The effects of stimulus distance, target size, display time, bits of information and the age group of the subject (young versus old) on the reading performance (information processing ability) under photopic and scotopic viewing conditions were thoroughly investigated in this study. Fifty-six individuals (28 young, 28 elderly) from the Montgomery County region were tested in the study in a mixed factorial repeated measures design with age as between subjects and the other independent variables as within subjects. The dependent variable was the reading score, i.e., the number of letters correctly identified. Results obtained from this study revealed that all of the independent variables had significant effects on the reading performance of the participants, except ambient illumination. Specifically, age has an important influence on the specific values of the design parameters. Also, these parameters interact among themselves so that one can be used to compensate for the other. These results can be used for developing the most relevant and optimal in-vehicle visual displays for the older population. / Master of Science