Humans have evolved under a field of low level radiation, and continue to be exposed to ubiquitous levels from natural and man-made sources including diagnostic radiology. The computerized tomography scan, in particular, plays an important role in the investigation of disease and its use increased dramatically over the years. This raises the concern that elevation in radiation exposure from x-ray modalities may increase an individual's risk for cancer. The purpose of this study is to help address this issue by measuring biological changes in lymphocytes before and after a CT scan. Venous blood was collected from eight prostate cancer patient:> before and after their scan and delivered to McMaster University at room temperature. For the dicentric assay, 0.5 ml whole blood/tube was irradiated with 3 Gy gamma rays using a 0 ;137 source and then incubated at 37°C for 46 hours. Metaphases were scored by microscopy. For apoptosis and y-H2AX, lymphocytes in media were irradiated on ice with 8 Gy and analyzed by flow cytometry. Biological effects in vivo from the CT scan were minimal for all endpoints when averaged between all donors. Overall, there was a high degree of inter-individual variation for each effect, although no correlation was found between dose (dose length product) from CT and apoptosis as well as the induction of yH2AX foci. The adaptive response also showed patient variation, and the frequency of dicentrics was the only endpoint that was lower overall following CT + 3Gy in comparison to 3 Gy alone. This research presents a challenge to current linear models of radiation associated genetic risk, and shows that individuals respond to radiation differently depending on biological factors. / Thesis / Master of Science (MSc)

Yes / Age estimation methods are often based on the age-related morphological changes of the auricular surface and the pubic bone. In this study, a mathematical approach to quantify these changes has been tested analyzing the curvature variation on 3D models from CT and laser scans. The sample consisted of the 24 Suchey–Brooks (SB) pubic bone casts, 19 auricular surfaces from the Buckberry and Chamberlain (BC) “recording kit” and 98 pelvic bones from the Terry Collection (Smithsonian Institution). Strong and moderate correlations between phases and curvature were found in SB casts (ρ 0.60–0.93) and BC “recording kit” (ρ 0.47–0.75), moderate and weak correlations in the Terry Collection bones (pubic bones: ρ 0.29–0.51, auricular surfaces: ρ 0.33–0.50) but associated with large individual variability and overlap of curvature values between adjacent decades. The new procedure, requiring no expert judgment from the operator, achieved similar correlations that can be found in the classic methods.

Doctor of Philosophy / Department of Physics / Dean A. Zollman / In this study we explored students' transfer of learning in the X-ray medical imaging context, including the X-ray-based computer-assisted tomography (or CAT). For this purpose we have conducted a series of clinical and teaching interviews. The investigation was a part of a bigger research effort to design teaching-learning materials for pre-medical students who are completing their algebra-based physics course. Our students brought to the discussion pieces of knowledge transferred from very different sources such as their own X-ray experiences, previous learning and the mass media. This transfer seems to result in more or less firm mental models, although often not internally consistent or coherent. Based on our research on pre-med students' models of X-rays we designed a hands-on lab using semi-transparent Lego bricks to model CAT scans. Without "surgery" (i.e. without intrusion into the Lego "body") students determined the shape of an object, which was built out of opaque and translucent Lego bricks and hidden from view. A source of light and a detector were provided upon request. Using a learning cycle format, we introduced CAT scans after students successfully have completed this task. By comparing students' ideas before and after teaching interview with the groups of 2 or 3 participants, we have investigated transfer of learning from basic physics and everyday experience to a complex medical technology and how their peer interactions trigger and facilitate this process. During the last phase of our research we also introduced a CAT-scan simulation problem into our teaching interview routine and compared students' perception of this simulation and their perception of the hands-on activity.

A characteristic feature of Chronic Obstructive Pulmonary Disease (COPD) is an abnormal inflammatory response in the lungs to inhaled particles or gases. The ability to assess and monitor this response in the lungs of COPD patients is important for understanding the pathogenic mechanisms, but also provides a measure of the activity of the disease. Disease activity is more likely to relate to lung inflammation rather than the degree of airflow limitation as measured by the FEV1. Preliminary studies have shown the 18F fluorodeoxyglucose positron emission tomography (18F FDG-PET) signal, as a measure of lung inflammation, is quantifiable in the lungs and is increased in COPD patients compared to controls. However, the methodology requires standardisation and any further enhancement of the methodology would improve its application to assess inflammation in the lungs. I investigated various methods of assessing FDG uptake in the lungs and assessed the reproducibility of these methods, and particularly evaluated whether the data was reproducible or not in the COPD patients (smokers and ex-smokers). This data was then compared with a group of healthy controls to assess the role of dynamic 18F FDG-PET scanning as a surrogate marker of lung inflammation. My data showed a good reproducibility of all methods of assessing FDG lung uptake. However, using conventional Patlak analysis, the uptake was not statistically different between COPD and the control group. Encouraging results in favour of COPD patients were nonetheless shown using compartmental methods of assessing the FDG lung uptake, suggesting the need to correct for the effect of air and blood (tissue fraction effect) when assessing this in a highly vascular organ like the lungs. A prospective study analysis involving a bigger cohort of COPD patients would be desirable to investigate this further.

Delirium is a severe neuropsychiatric syndrome, characterised by the acute onset of inattention, altered level of arousal, and other mental status abnormalities. Delirium is extremely common in acute stroke, affecting at least 1 in 5 such patients admitted to hospital. It is a serious complication of stroke, being associated with higher mortality, longer length of hospital stay and higher dependency at discharge. The pathophysiology of delirium is not completely understood, and there are no specific treatments. This thesis investigated the role of cortisol in the development of delirium after stroke and also investigated the role of delirium and of cortisol in the development of cognitive impairment in the 12 months after stroke. The thesis specifically investigated whether levels of cortisol in saliva are elevated in delirium and also whether there is a loss of the normal diurnal rhythm in delirium, evidenced by elevated afternoon salivary cortisol levels and reduced morning level to afternoon level ratio. The thesis also investigated whether cortisol levels are persistently elevated in the year after stroke in those who developed delirium and whether cortisol levels are associated with cognitive decline. Finally it investigated whether acute and/or chronic changes seen on Computed Tomography (CT) brain scans taken around the time of stroke onset are associated with the development of delirium after stroke A longitudinal cohort study was conducted in 95 participants aged 60 years or over, who were admitted to hospital with a clinically confirmed stroke. Participants gave informed consent, or proxy consent was obtained if they lacked capacity to consent. At baseline participants underwent brief cognitive testing and were then assessed for the presence of delirium, using DSM IV criteria, at regular intervals during the first two weeks after stroke. At each assessment a saliva sample was collected in the morning and in the afternoon, to measure cortisol. Participants were then visited at 1 month, 4 months and 12 months after stroke onset, at which point they were assessed for the presence of delirium, further saliva samples were taken and a cognitive test battery was completed. 26 (27%) participants developed delirium during the course of the study period. The study found elevated salivary cortisol levels in those with delirium at up to 4 months after stroke, but at 12 months there was no difference between the delirium and no delirium group. A loss of the diurnal rhythm was seen in those who developed delirium at 5 days after stroke, but the diurnal variation had returned to a normal pattern at follow-up. However, in a multivariate analysis, controlling for age, sex, stroke severity (NIHSS), current illness burden (APACHE II), chronic illness burden (CCI) and prior cognitive impairment (IQCODE), neither median salivary cortisol levels in the first two weeks after stroke, nor the ratio of morning to afternoon cortisol levels were independent predictors of delirium diagnosis, although median 9am cortisol approached significance (OR=0.95, 95% confidence interval (CI) 0.89-1.01, p=0.08). In a random effects logistic regression analysis, the probability of developing delirium decreased over time from stroke onset and increased per unit increase in salivary cortisol (nmol/L), however this effect was not statistically significant (OR 1.02, CI 0.84-1.19 P=0.70 for morning cortisol and OR 1.05, CI 0.82-1.25 p=0.46 for afternoon cortisol). Global cognition, measured by the MoCA, was significantly poorer in the delirium group at each time point throughout the 12 months after stroke. However, there was a trend towards improvement in MoCA scores in the whole cohort throughout the 12 month follow-up, with the exception of those who developed the most severe delirium. The presence of delirium at any point during the 12 month follow-up did not affect the rate of change of the MoCA scores over the 12 months after stroke. The presence of brain atrophy identified on admission CT brain scans was independently associated with delirium (OR 3.7, CI 1.15-11.88, p=0.02), however the presence of a visible acute or chronic stroke lesion and the presence of white matter lesions were not. Finally, those who developed delirium had a worse functional outcome, longer length of hospital stay and were more likely to require institutional care or a package of care at home, compared with those who did not develop delirium. This thesis has contributed to our understanding of the mechanisms and phenomenology of delirium after stroke, and has also highlighted areas for further research which will be required to unpick the complex pathophysiology of delirium.

abstract: Neuroimaging has appeared in the courtroom as a type of `evidence' to support claims about whether or not criminals should be held accountable for their crimes. Yet the ability to abstract notions of culpability and criminal behavior with confidence from these imagines is unclear. As there remains much to be discovered in the relationship between personal responsibility, criminal behavior, and neurological abnormalities, questions have been raised toward neuroimaging as an appropriate means to validate these claims. This project explores the limits and legitimacy of neuroimaging as a means of understanding behavior and culpability in determining appropriate criminal sentencing. It highlights key philosophical issues surrounding the ability to use neuroimaging to support this process, and proposes a method of ensuring their proper use. By engaging case studies and a thought experiment, this project illustrates the circumstances in which neuroimaging may assist in identifying particular characteristics relevant for criminal sentencing. I argue that it is not a question of whether or not neuroimaging itself holds validity in determining a criminals guilt or motives, but rather a proper application of the issue is to focus on the way in which information regarding these images is communicated from the `expert' scientists to the `non-expert' making decisions about the sentence that are most important. Those who are considering this information's relevance, a judge or jury, are typically not well versed in criminal neuroscience and interpreting the significance of different images. I advocate the way in which this information is communicated from the scientist-informer to the decision-maker parallels in importance to its actual meaning. As a solution, I engage Roger Pielke's model of honest brokering as a solution to ensure the appropriate use of neuroimaging in determining criminal responsibility and sentencing. A thought experiment follows to highlight the limits of science, engage philosophical repercussions, and illustrate honest brokering as a means of resolution. To achieve this, a hypothetical dialogue reminiscent of Kenneth Schaffner's `tools for talking' with behavioral geneticists and courtroom professionals will exemplify these ideas. / Dissertation/Thesis / Masters Thesis Biology 2014

abstract: Shunt capacitors are often added in transmission networks at suitable locations to improve the voltage profile. In this thesis, the transmission system in Arizona is considered as a test bed. Many shunt capacitors already exist in the Arizona transmission system and more are planned to be added. Addition of these shunt capacitors may create resonance conditions in response to harmonic voltages and currents. Such resonance, if it occurs, may create problematic issues in the system. It is main objective of this thesis to identify potential problematic effects that could occur after placing new shunt capacitors at selected buses in the Arizona network. Part of the objective is to create a systematic plan for avoidance of resonance issues. For this study, a method of capacitance scan is proposed. The bus admittance matrix is used as a model of the networked transmission system. The calculations on the admittance matrix were done using Matlab. The test bed is the actual transmission system in Arizona; however, for proprietary reasons, bus names are masked in the thesis copy in-tended for the public domain. The admittance matrix was obtained from data using the PowerWorld Simulator after equivalencing the 2016 summer peak load (planning case). The full Western Electricity Coordinating Council (WECC) system data were used. The equivalencing procedure retains only the Arizona portion of the WECC. The capacitor scan results for single capacitor placement and multiple capacitor placement cases are presented. Problematic cases are identified in the form of ‘forbidden response. The harmonic voltage impact of known sources of harmonics, mainly large scale HVDC sources, is also presented. Specific key results for the study indicated include: • The forbidden zones obtained as per the IEEE 519 standard indicates the bus 10 to be the most problematic bus. • The forbidden zones also indicate that switching values for the switched shunt capacitor (if used) at bus 3 should be should be considered carefully to avoid resonance condition from existing. • The highest sensitivity of 0.0033 per unit for HVDC sources of harmonics was observed at bus 7 when all the HVDC sources were active at the same time. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2015-05-28T13:51:55Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE Alexandre Honório da Silva.pdf: 8740753 bytes, checksum: ba6d7cdc63c97a4c14518844dd40fce5 (MD5) / Made available in DSpace on 2015-05-28T13:51:55Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE Alexandre Honório da Silva.pdf: 8740753 bytes, checksum: ba6d7cdc63c97a4c14518844dd40fce5 (MD5) Previous issue date: 2015-03-23 / Esta pesquisa propõe que a transição hipertecnológica e midiático-colaborativa de uma forma cultural guarda elementos, indícios, pistas compartilhadas por outras expressões igualmente submetidas a tal processo. Assim, partindo da observação e análise do entorno subcultural de blogs, grupos e comunidades online dedicadas à digitalização e preservação colaborativa de Histórias em Quadrinhos - através de um artefato midiático-colaborativo denominado scan -, sugerimos que transições deste gênero expressam uma busca hipertecnológica, hipermediada e hipermoderna por experimentação, afirmação e pertencimento. Os scans, mais que representarem a contraparte digital de um artefato transposto de seu lugar original para uma nova e outra instância de experimentação, expressariam as transformações de um ecossistema comunicacional-cultural. Para chegarmos a tais conlusões realizamos partimos de uma abordagem virtual-etnográfica destas comunidades - observando as rotinas, processos e modos de atuação/fazer - coletando dados ainda sobre como seus usuários veem não apenas suas práticas, mas como esta se faz manifesta no domínio do fã de uma forma cultural como a das Histórias em Quadrinhos. Além disso, propomos uma análise teórico-referencial com ênfase nos estudos da mídia, da cultura e das tecnologias que procura elucidar como um entorno cultural-midiático tradicional foi adaptado e transposto colaborativamente não apenas para o atendimento de uma transição experimentada por seus interlocutores mais próximos - usuários e consumidores - mas, sobretudo, com impacto em um reconhecido artefato midiático e na sua configuração original.

Ein alltagstauglicher autonomer Assistenzroboter in einem gemeinsamenArbeitsumfeld mit dem Menschen erfordert, dass der Roboter sämtliche Hindernisse in seiner Umgebung wahrnimmt und diesen sicher ausweicht. Stand der Technik ist jedoch, dass meist nur 2D-Sensordaten zur Navigation herangezogen werden. Oder es werden3D-Verfahren verwendet, die ausschließlich mit einer speziellen Sensorkonfiguration arbeiten. Diese Arbeit untersucht im Rahmen des LiSA-Projekts wie 3D-Sensordaten effizient und flexibel zur sicheren Navigation eines autonomenAssistenzsystems eingesetzt werden können. Dazu wird in dieser Arbeit mit der Virtual Range Scans (VRS)-Methode ein Verfahren zurHindernisvermeidung entwickelt, das beliebige Konfigurationen von Abstandssensoren in den Hindernisvermeidungsprozess integriert. Das Verfahren nutztklassische Verfahren zur 2D-Hindernisvermeidung, um 3D-Hindernisvermeidung zu realisieren. Dadurch wird das VRS-Verfahren unabhängig von der Hindernisvermeidungsstrategie und kann flexibel bestehende Verfahren wiederverwenden. Neben der Hindernisvermeidung wird gezeigt, wie die reichereUmgebungsinformation, die in 3D-Sensordaten vorhanden ist, zur robusteren Selbstlokalisierung des Roboters genutzt werden kann. Hier wird eineffizientes Verfahren vorgestellt, das Abstandssensordaten mit 3D-Umgebungsmodellen vergleicht. Ferner wird ein Verfahren vorgestellt, das Semantikim Umfeld des Roboters verankert und sie zur Navigation des Roboters nutzt.

Beginning the study with a regional network map with an intent to perform a detailed harmonic study for a certain location, the first question that comes up is how far out in the system should detailed modeling of individual devices (transmission lines, loads, transformers, capacitor banks, etc) be done. The reason why this is extremely important is because system components that will affect the frequency response characteristics in the specific location should not be missed or poorly modeled. Frequency scan is the simplest and most commonly used simulation technique used to characterize the response of a power system network as a function of frequency. Unfortunately, there are two major problems using frequency scan techniques when real harmonic studies are considered: 1) the size of the admittance matrices (this calculation is repeated using discrete frequency steps throughout the range of interest) may be so large that an exact mathematical model of the system is not realistic and 2) the complexity of a rigorous and complete mathematical model of the system does not necessarily explain the extent to which system components affect the frequency response characteristics in a specified location. It is seldom clear how much of the system must be represented in order to get accurate results in a harmonic study. Realistic procedures to identify whether to include a particular element in a detailed model or to lump the element into a simplifying equivalent are yet to be developed in the industry. It is safe to say that practicing engineers are using tools and techniques of questionable validity. Two new computer-oriented methods that use eigen analysis techniques to identify easily and accurately the boundary between system areas to be modeled in detail and those represented by equivalents are proposed in this dissertation. The key here is to recognize that not all elements present in the ?external? system will participate in the resonant harmonic modes and could therefore be lumped into a simplified short-circuit equivalent. Achieving these objectives from either one of the two methods can be economically attractive. In short, the work described in this dissertation is a fundamentally sound alternative for the purposes of network equivalencing and model reduction.