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Verotoxin-producing Escherichia coli (VTEC) of serotype O157:H7 is a pathogen causing illness in humans worldwide. The path and nature of transmission from and among cattle is important knowledge when it comes to preventing cases of disease in humans. Two concepts potentially playing an important role in transmission of VTEC O157:H7 are super-shedding and super-spreading. Super-shedders are individuals (here calves) shedding a high amount of bacteria. Super-spreaders are individuals (here calves) spreading the disease in a higher extent compared to the rest of the population investigated. Little is known about these phenomenons’ effect on transmission as well as the relation between them. Therefore, it is important to investigate this further. The purpose of this master thesis was to get a better understanding of how super-spreaders can be identified. One way to identify super-spreaders and explore the transmission of a pathogen is to investigate molecular data using computational methods. Here, a literature study with a systematic approach was conducted in order to scan the literature for such methods. In this first phase of the master thesis three methods, all constructing transmission trees, were identified as relevant methods for the second phase. These methods are called outbreaker2, phybreak and TransPhylo. In the second phase of the master thesis, 32 whole genome sequences of VTEC O157:H7 collected from four different cattle farms were investigated using the methods outbreaker2 and phybreak. Both methods were able to identify samples infecting more secondary cases compared to the rest of the investigated population. Some of these samples came from the environment, possibly shedding light on the importance of the pathogen's ability to survive outside of the host, and therefore playing an important role in transmission of the disease. The rest of the samples infecting more secondary cases were from calves, and a minority of these were super-shedders. From this the importance of the relation between super-shedders and super-spreaders can neither be confirmed nor denied. Outbreaker2 suggested that the spread of the pathogen is frequently occurring between the four neighbouring farms, while phybreak instead suggested that the spread mostly occurs within the farms. From this, a scenario explaining that the transmission possibly occurs within farms is presented.

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International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / Half inch Super VHS (S-VHS) tape is an exceptional media for recording telemetry instrumentation data. Due to high volume mass production for the commercial and industrial video markets, high quality S-VHS media is available at a low cost. Advances in head technology as well as data path electronics contribute to increased data densities recorded on this media. Present system capabilities of 50,000 bits per inch will soon be replaced with newer technology systems that will record at linear densities up to 100,000 bits per inch.

International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / This paper describes the technology on transmitting a single super fast waveform signal in real-time and introduces the general situation of the telemetry transmitter in vehicle. The equipment is a FM system in view of RF frequency, it is a pulse system in view of RF power. This equipment can transfer not only super fast waveform signals but also slowly varying conventional telemetry signals. The design is very novel. It is a multi-usage telemetry transmitter in vehicle.

Fluorescence microscopy is an important tool for biological research. However, the resolution of a standard fluorescence microscope is limited by diffraction, which makes it difficult to observe small details of a specimen’s structure. We have developed two fluorescence microscopy methods that achieve resolution beyond the classical diffraction limit. The first method represents an extension of localisation microscopy. We used nonnegative matrix factorisation (NMF) to model a noisy dataset of highly overlapping fluorophores with intermittent intensities. We can recover images of individual sources from the optimised model, despite their high mutual overlap in the original dataset. This allows us to consider blinking quantum dots as bright and stable fluorophores for localisation microscopy. Moreover, NMF allows recovery of sources each having a unique shape. Such a situation can arise, for example, when the sources are located in different focal planes, and NMF can potentially be used for three dimensional superresolution imaging. We discuss the practical aspects of applying NMF to real datasets, and show super-resolution images of biological samples labelled with quantum dots. It should be noted that this technique can be performed on any wide-field epifluorescence microscope equipped with a camera, which makes this super-resolution method very accessible to a wide scientific community. The second optical microscopy method we discuss in this thesis is a member of the growing family of structured illumination techniques. Our main goal is to apply structured illumination to thick fluorescent samples generating a large out-of-focus background. The out-of-focus fluorescence background degrades the illumination pattern, and the reconstructed images suffer from the influence of noise. We present a combination of structured illumination microscopy and line scanning. This technique reduces the out-of-focus fluorescence background, which improves the quality of the illumination pattern and therefore facilitates reconstruction. We present super-resolution, optically sectioned images of a thick fluorescent sample, revealing details of the specimen’s inner structure. In addition, in this thesis we also discuss a theoretical resolution limit for noisy and pixelated data. We correct a previously published expression for the so-called fundamental resolution measure (FREM) and derive FREM for two fluorophores with intermittent intensity. We show that the intensity intermittency of the sources (observed for quantum dots, for example) can increase the “resolution” defined in terms of FREM.

A modified plate load (MPL) test was developed to measure the in situ cohesion of a carbonate or caliche cemented soil. The MPL test was performed on the crest of a vertical cut in alluvial soil with a steel plate loaded until the soil failed. A three-dimensional slope stability analysis was then used to back calculate soil cohesion. In situ test results were used in conjunction with laboratory testing of deaggregated soils samples to completely define the Mohr-Coulomb strength parameters of the in situ soil. In order to check the result of the in situ test procedure, the field test conditions were modeled for use in a two-dimensional slope stability analysis using the computer program CSLIP1. A comparison of the results shows reasonable values of soil cohesion were obtained using the MPL test method.

An emerging trend in the building services industry is the installation of passive deaerators on the flow line of domestic wet central heating systems. To date, no data and theoretical models predicting the two-phase flow characteristics in domestic wet central heating systems are available in the open literature. This gap in literature has prevented essential design improvements to passive deaerators thus impeding the efficiency enhancement of such devices. Hence, the current study is aimed at assisting designers of deaeration devices by providing fundamental data and model correlations with respect to the two-phase flow characteristics typical in a wet domestic central heating system. For this purpose an experimental research project was adopted and several studies were carried out, including; (1) a comprehensive review to understand the background of the phenomena, (2) the design and construction of an experimental test rig to conduct the necessary investigations into the phenomenon of two-phase flow in domestic wet central heating systems, (3) the development of a reliable image capture and analysis technique, (4) the completion of a number of experiments to investigate typical bubble sizes, volumetric void fractions, bubble distributions and nucleation and dissolution rates and (5) the correlation of the data gathered as part of the present study with existing bubble size, nucleation and dissolution prediction models. This research has, for the first time, provided an in depth analysis into two-phase flow characteristics in wet domestic central heating systems through the use of a high speed camera and image analysis techniques. The two-phase phenomenon finds its origins in high dissolved gas concentrations present in the water flowing through the closed loop system, thus resulting in super saturation conditions at the primary heat exchange wall conditions. Bubble sizes at the boiler flow line were found to be dependent on the bulk fluid velocity, heat flux and pressure, with a measured mean diameter in the range of 0.13 mm to 0.39 mm. The Winterton (1972a) force balance model for bubble size prediction was in reasonable agreement with the experimental results. This model was further improved through the correlation of our data with the inclusion of dimensionless groups. Bubble nucleation rates have been calculated in the range of 0.3 to 4 bubbles / cm2 s with total system bubble production rates measured in the range of 784 to 6920 bubbles per second. Bubble nucleation rates have been calculated through the consideration of the heat exchanger surface under super saturation conditions. A correlation for the model by Hepworth et al. (2003) for nonclassical heterogeneous nucleation is proposed based on the experimental data gathered during the present study. Experimental results have shown dissolution rates for the bubble size ratio in the range of 0.4 to 12 % per second with system conditions. A modification of the model developed by Epstein and Plesset (1950) for stationary bubble dissolution is proposed with the inclusion of the Sherwood number to capture the effects of turbulent diffusion. The volumetric void fraction distribution in vertical pipes was found to be quasi-homogenous across the pipe section while being strongly dependent on gravitational and turbulence effects in horizontal pipe bubbly flow. A CFD simulation predicted the volumetric void fraction distribution with reasonable accuracy.

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<p>Optical microscopy plays a crucial role in the biological sciences for its ability to enable visualization of biological samples at sub-cellular levels. Many imaging subdivisions exist under this umbrella of general microscopy, and each are tailored towards specific design, contrast, and visualization constraints. Standard examples that have found widespread use include dark-field, phase-contrast, holographic, and fluorescent microscopies. However, a critical factor that physically limits the optical resolution of general microscopy is diffraction. Unfortunately, this “diffraction-limit” can prevent visualization of significant biologically relevant structures, which in turn can limit biological insights. In response to such a limit, several works have advanced the field of sub-diffraction resolution imaging, which consist of optical imaging techniques that seek to achieve imaging resolutions beyond that which is allowed by the diffraction-limit. This set of techniques can largely be divided into two classes. The first class of sub-diffraction techniques is targeted towards cases where the sample is coherently illuminated and diffracts into the imaging system’s aperture. For such cases, synthetic aperture (SA) is a popular choice and operates by using oblique illuminations to spatiotemporally synthesize a wider frequency support into the image than allowed by the diffraction limit. The second class of sub-diffraction techniques, often referred to as "super-resolution" techniques, typically utilize specialized fluorophores with either photoswitching or depletion capabilities. Photoactivated localization microscopy (PALM) is a super-resolution example that localizes photoswitchable fluorophores to sub-diffraction resolutions per acquisition, before combining into a final super-resolved image. Stimulated emission depletion (STED) is another super-resolution example that spatially modulates its excitation to narrow its optical point-spread-function. Unfortunately, SA and fluorescent super-resolution techniques are generally incompatible for sub-diffraction resolution fluorescent and coherent imaging, respectively – thus, a multimodal sub-diffraction imaging solution compatible with both coherent and fluorescent imaging has remained elusive. </p><p> In this dissertation, we demonstrate that structured illumination (SI) is a sub-diffraction technique compatible with both diffractive and fluorescent imaging. We first develop the theoretical framework that extends SI to coherent imaging and experimentally demonstrate SI’s capabilities for 2D sub-diffraction resolution imaging of coherently diffractive samples. Sub-diffraction resolution imaging based on scattering intensity and transmission-based quantitative-phase (QP) are shown. In addition, we show extend SI to 3D coherent imaging, and show applications of this towards 3D QP and refractive-index (RI) tomography. Finally, we show multimodal applications of SI that allow sub-diffraction resolution fluorescent and coherent imaging, which has great potential utility for the biological sciences.</p> / Dissertation