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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.
171

Seizure and Behavioral Phenotyping of the Scn1a Mouse Model of Genetic Epilepsy with Febrile Seizures Plus

Helvig, Ashley W. 07 December 2012 (has links)
Genetic epilepsy with febrile seizures plus (GEFS+) is associated with a wide range of neurological dysfunction caused in part by limited function in voltage-gated sodium channels (Escayg & Goldin, 2010; Gambardella & Marini, 2009; Mulley et al., 2005). The seizure and behavioral phenotypes, as well as use of non-pharmacologic agents as neuroprotectants in GEFS+, are not well-understood. An experimental design used an animal model of GEFS+ to 1. explore the effects of stress on seizure phenotype, 2. examine behavioral phenotypes, and 3. study the effects of an omega 3 fatty acid on abnormal behaviors noted in the various paradigms. This study used C57BL/6J mice with the R1648H missense mutation on the Scn1a gene (engineered in the Escayg lab) (Martin, M. S. et al., 2010). The three specific aims used separate groups of animals for experimentation, and all paradigms were performed under strict laboratory conditions. Data were analyzed using either an independent t-tests, two-way ANOVA or repeated measures two-way ANOVA. Results showed that stress worsens seizure phenotype in both the Scn1aR1648H (RH) mutants and wild-type (WT) group with the RH mutants more severely impacted. In addition, there was clear and consistent evidence for hyperactive locomotor behavior. Lastly, no evidence was found for use of docosahexaenoic acid (DHA, an omega 3 fatty acid) as a neuroprotectant for hyperactivity (DHA was given subcutaneously for two weeks starting at weaning). Outcomes from this study implicate that stress worsens the seizure phenotype in animals with Scn1aR1648H. This study is also the first to report hyperactive locomotor behavior in animals with Scn1aR1648H. Results from this study may broaden beyond GEFS+ in that we may also be able to apply the findings to other disorders with SCN1A dysfunction. In addition, it may be that genetic variants affecting SCN1A, but not necessarily in epilepsy, may contribute to hyperactivity. This could mean that SCN1A is a candidate gene for hyperactivity. The main goal of nursing care is to reduce and prevent disease morbidity, and knowledge gained from the current study will guide clinical nursing practice, such as targeted behavioral assessment and education, as well as nursing research focusing on children with this genetic disorder.
172

Bildbaserad rendering : Implementation och jämförelse av två algoritmer

Härdling, Peter January 2010 (has links)
Det här arbetet har gått ut på att jämföra två algoritmer för bildbaserad rendering. Båda algoritmerna använder två bilder som spelats in med formatet MultiView plus depth för att rendera nya mellanliggande vyer av en tredimensionell scen. De tvådimensionella bilderna är kompletterade med djupvärden för varje bildpunkt. Renderingen kan då utföras genom perspektivriktiga transformationer där alla bildpunkters nya positioner projiceras individuellt. I samband med renderingen behöver bland annat mätfel i de ursprungliga bilderna samt skymda partier hanteras. Algoritm I gör det delvis genom utjämning av skarvararna mellan bildernas bidrag till den nya vyn. Algoritm II bygger på att bilderna delas upp i lager där de lager som ansetts vara säkra prioriteras framför lager som har bedömts vara mer riskabla. Algoritmerna har implementerats i Matlab och algoritm II har modifierats genom kompletteringar av dess regler för prioriteringen av lagren till mer komplicerade scener. Algoritm II har visat sig vara bättre på att bevara detaljer i de renderade vyerna och håller en jämnare hastighet vid renderingarna. Den ger även högre och jämnare resultat vid jämförelse med kvalitetsmåttet PSNR men vid jämförelser med MSSIM har den däremot fått något lägre värden. De ytterligare stegen vid renderingen har även ökat renderingstiderna med upp till 40 % jämfört med algoritm I. Författaren ger förslag på områden för fortsatt utveckling av algoritm II. Till exempel bör algoritmen testas vidare för att avgöra om de använda gränsvärdena är generella eller om de måste anpassas till olika scener. / This thesis has been aimed at comparing two algorithms for image-based renderings. Both algorithms uses two images recorded with the MultiView plus depth format, to render new intermediate views of a three-dimensional scene. The two-dimensional images extensions with depth values for each pixel, makes it possible to perform the image warping as perspective projections of all individually pixels to their new positions. During rendering, such as measurement error in the original images and occlusions has to be handled. Algorithm I is partly based on smoothening the joints between the contributions from the two images to the novel view. Algorithm II divides the images into layers, in which layers consid-ered safe has priority over layers that have been defined as more risky. The algorithms have been implemented in Matlab and algorithm II has been modified through additions to the priority rules for the layers to more complex scenes. Algorithm II has proven to be better at preserving the details in the rendered views, and maintains a less varying speed when rendering. It also provides higher and more consistent PSNR values, but in comparison using MSSIM the values are slightly lower. The additional steps have also increased the rendering times by up to 40 % compared to algorithm I. The author suggests areas for further development of algorithm II. For example, the algorithm should be tested further to determine if the used thresholds are general or whether they must be adapted to different scenes.
173

Techno-Economic Study of CO<sub>2</sub> Capture Process for Cement Plants

Hassan, S. M. Nazmul January 2005 (has links)
Carbon dioxide is considered to be the major source of GHG responsible for global warming; man-made CO<sub>2</sub> contributes approximately 63. 5% to all greenhouse gases. The cement industry is responsible for approximately 5% of global anthropogenic carbon dioxide emissions emitting nearly 900 kg of CO<sub>2</sub> for every 1000 kg of cement produced! Amine absorption processes in particular the monoethanolamine (MEA) based process, is considered to be a viable technology for capturing CO<sub>2</sub> from low-pressure flue gas streams because of its fast reaction rate with CO<sub>2</sub> and low cost of raw materials compared to other amines. However, MEA absorption process is associated with high capital and operating costs because a significant amount of energy is required for solvent regeneration and severe operating problems such as corrosion, solvent loss and solvent degradation. This research was motivated by the need to design size and cost analysis of CO<sub>2</sub> capture process from cement industry. MEA based absorption process was used as a potential technique to model CO<sub>2</sub> capture from cement plants. In this research four cases were considered all to reach a CO<sub>2</sub> purity of 98% i) the plant operates at the highest capacity ii) the plant operates at average load iii) the plant operates at minimum operating capacity and iv) switching to a lower carbon content fuel at average plant load. A comparison among four cases were performed to determine the best operating conditions for capturing CO<sub>2</sub> from cement plants. A sensitivity analysis of the economics to the lean loading and percent recovery were carried out as well as the different absorber and striper tray combinations.
174

Behavioural consequences of kindling in the anterior claustrum

Ma, Bonita 30 May 2007 (has links)
The anterior claustrum (CLA) has been implicated in epileptogenesis and epileptiform activity due to its abundant and widespread bilateral connections to some of the structures believed to play an important role in seizure generalization: the motor cortex, entorhinal cortex, limbic structures, and brainstem sites. Kindling in the CLA has been characterized as comprising two distinct phases: an early phase and a late phase. Early phase seizures progress quickly into generalized seizures, are short in duration, and resemble cortical seizures. Late phase seizures are characterized as being more severe in intensity, having longer durations, and resembling limbic-type seizures.<p>It is unknown whether kindling in the CLA will lead to changes in behaviour as seen after kindling of limbic sites. Thus, I measured the behavioural effects of kindling in the anterior CLA to investigate potential changes in learning, memory, and anxiety-related behaviours. I hypothesized that changes in behaviour would occur after kindling of late phase seizures, because of their close resemblance to limbic-type seizures, but not after kindling of early phase seizures. Anxiety-like behaviour was assessed in the elevated plus maze and open field. Object memory was assessed in an object recognition test, and spatial learning and memory were assessed in the water maze.<p>I found no significant changes in behaviour in the late phase group in comparison to the early phase and control groups. Thus, contrary to my hypothesis, late phase kindling of the CLA does not produce changes in learning and memory or alterations in anxiety-related behaviours.
175

Thermodynamics of CO₂ loaded aqueous amines

Xu, Qing, doctor of chemical engineering. 31 January 2012 (has links)
Thermodynamics is important for the design of amine scrubbing CO₂ capture processes. CO₂ solubility and amine volatility in aqueous amines were measured at high temperature and pressure. A rigorous thermodynamic model was developed for MEA-CO₂-H₂O in Aspen Plus®. CO₂ solubility at 80-190°C was obtained from total pressure measurements. Empirical models as a function of temperature and loading were developed for CO₂ solubility from 40 to 160°C in aqueous monoethanolamine (MEA), piperazine (PZ), 1-methylpiperazine (1MPZ), 2-methylpiperazine (2MPZ), PZ/2MPZ, diglycolamine® (DGA®), PZ/1MPZ/1,4-dimethylpiperazine (1,4-DMPZ), and PZ/methyldiethanolamine (MDEA). The high temperature CO₂ solubility data for MEA is comparable to literature and compatible with previous low temperature data. For MEA and PZ, amine concentration does not have obvious effects on the CO₂ solubility. The heat of CO₂ absorption derived from these models varies from 66 kJ/mol for 4 m (molal) PZ/4 m 2MPZ and to 72, 72, and 73 kJ/mol for MEA, 7 m MDEA/2 m PZ, and DGA. The heat of absorption estimated from the total pressure data does not vary significantly with temperature. At 0-0.5 loading ([alpha]), 313-413 K, 3.5-11 m MEA (mol fraction x is 0.059-0.165), the empirical model of MEA volatility is ln(PMEA/xMEA) = 30.0-8153/T-2594[alpha]²/T. In 7 m MEA with 0.2 and 0.5 loading, PMEA is 920 and 230 Pa at 120°C. At 0.3-0.5 loading, the enthalpy of MEA vaporization, -[Delta]Hvap,MEA, is about 70-73 kJ/mol MEA. At 0.25-0.4 loading, 313-423 K, 4.7-11.3 m PZ (x is 0.078-0.169), the empirical model of PZ volatility is ln(PPZ/xPZ) = -123+21.6lnT+20.2[alpha]-18174[alpha]²/T. In 8 m PZ with 0.3 and 0.4 loading, PPZ is 400 and 120 Pa at 120°C, and 2620 and 980 Pa at 150°C. At 0.25-0.4 loading, -[Delta]Hvap,PZ is about 85-100 kJ/mol PZ at 150°C and 66-80 kJ/mol PZ at 40°C. [Delta]Hvap,PZ has a larger dependence on CO₂ loading than [Delta]Hvap,MEA in rich solution because of the more complex speciation/reactions in PZ at rich loading. Specific heat capacity of 8 m PZ is 3.43-3.81 J/(g•K) at 70-150°C. Two new thermodynamic models of MEA-CO₂-H₂O were developed in Aspen Plus® starting with the Hilliard (2008) MEA model. One (Model B) includes a new species MEACOOH and it gets a better prediction than the other (Model A) for CO₂ solubility, MEA volatility, heat of absorption, and other thermodynamic results. The Model B prediction matches the experimental pKa of MEACOOH, and the measured concentration of MEACOO-/MEACOOH by NMR. In the prediction the concentration of MEACOOH is 0.1-3% in 7 m MEA at high temperature or high loading, where the heat of formation of MEACOOH has effects on PCO₂ and CO₂ heat of absorption. Model B solved the problems of Model A by adding MEACOOH and matched the experimental data of pKa and speciation, therefore MEACOOH may be considered an important species at high temperature or high loading. Although mostly developed from 7 m MEA data, Model B also gives a good profile for 11 m (40 wt%) MEA. / text
176

Diagonal plus low rank approximation of matrices for solving modal frequency response problems

Vargas, David Antonio 10 February 2011 (has links)
If a structure is composed mainly of one material but contains a small amount of a second material, and if these two materials have significantly different levels of structural damping, this can increase the cost of solving the modal frequency response problem substantially. Even if the rank of the contribution to the finite element structural damping matrix from the second material is very low, the matrix becomes fully populated when transformed to the modal representation. As a result, the complex-valued modal matrix that represents the structure’s stiffness and structural damping is both full rank, because of the diagonal part contributed by the stiffness, and fully populated, because of off-diagonal imaginary terms contributed by the second material’s structural damping. Solving the modal frequency response problem at many frequencies requires either the factorization of a coefficient matrix at every frequency, or the solution of a complex symmetric eigenvalue problem associated with the modal stiffness/structural damping matrix. The cost of both of these approaches is proportional to the cube of the number of modes included in the analysis. This cost could be reduced greatly if the damping properties of the structure were handled carefully in modeling the structure, but in practical computation of the modal frequency response, the information that could potentially reduce the computational cost is often unavailable. This thesis explores the possibilities of obtaining a representation of the complex modal stiffness/structural damping matrix as a diagonal matrix plus a matrix of minimal rank. An algorithm for computing a “diagonal plus low rank” (DPLR) representation is developed, along with an iterative algorithm for using an inexact DPLR approximation in the solution of the modal frequency response problem. The behavior of these algorithms is investigated on several example problems. / text
177

Modeling of Kraft Mill Chemical Balance

Saturnino, Daniel M. 31 August 2012 (has links)
The reduction of mill effluent discharge as a result of stringent environmental legislations can have a significant impact on sodium (Na) and sulfur (S) balances in the kraft pulping process. In order to maintain a proper balance of Na and S, kraft mills may need to adopt different makeup strategies. For this purpose, a dynamic model was developed to predict the Na and S balance in the kraft recovery cycle, as well as the accumulation of undesirable non-process elements such as chlorine (Cl) and potassium (K). The model was developed using the CADSIM software and was validated using data obtained from a Brazilian bleached kraft pulp mill. The calculated data from the model showed good agreement with mill data with respect to all parts of the mill simulated. Dynamic tests designed to calculate the white liquor sulfidity over specific periods of time also presented good agreement. The result indicates that the model is able to describe the balance of chlorine, potassium, sodium and sulfur in the kraft process. A study conducted to evaluate the Cl and K accumulation agrees with the expected behaviour observed in mill data. The presence of ash treatment systems allow to reduce Cl and K contents in recovery boiler precipitator ash from 4.2 mol% Cl(Na+K) to 1.25 mol % and from 2.25 mol % K/(Na+K) to 0.8 mol% for 100% ash treated. The tests performed for Na and S balances focused in the makeup requirement for two situations: ash purging and ash treatment to control Cl and K levels. The use of ash treatment systems reduced Na and S makeup requirement from 5 to 50% depending on the amount of ash treated. A simple mathematical model was then used to estimate the Cl balances around the recovery cycle. Given that the proper simplifications are applied, the CADSIM model and the CSTR model presented good agreement in estimating the Cl balances. This result provided not only another method for the CADSIM model to be validated but also a way to calculate a rough estimate for Cl balance.
178

Understanding the plant ESCRT machinery and its role in tombusvirus-induced mitochondrial multivesicular body biogenesis

Richardson, Lynn 13 September 2012 (has links)
Carnation Italian ringspot virus (CIRV) is a positive-strand RNA virus that assembles its membrane-bound replication complexes at mitochondria in plant cells. This process is accompanied by extensive inward invagination of the mitochondrial outer membrane, leading to the formation of cytosol-filled spherules, wherein viral RNA synthesis occurs. The mechanism by which CIRV is able to induce spherule formation is unknown, however growing evidence suggests that the host-cell ESCRT (Endosomal Sorting Complex Required for Transport) machinery – a multi-protein complex normally involved in late endosome maturation – may be involved. ESCRT consists of ~30 soluble proteins that form sub-complexes assembled at the late endosomal surface, and function in multivesicular body (MVB) biogenesis. While ESCRT is relatively well characterized in yeasts and mammals, comparably little is known about ESCRT in plants. Hence, as an initial step towards understanding the potential role of ESCRT in CIRV replication, we examined the protein-protein interaction network, subcellular localization, and gene expression profiles of the Arabidopsis thaliana ESCRT components. Overall, the results from these studies suggest that ESCRT organization and function is relatively well conserved in plants compared to other eukaryotes. We also observed that ESCRT is important for CIRV replication, as expression of dominant-negative versions of several key ESCRT components reduced CIRV replication efficiency in plant cells. Moreover, the Arabidopsis ESCRT-I component, Vps23A is recruited from late endosomes to mitochondria in plant cells expressing the CIRV replicase protein, p36, and recruitment of Vps23A was shown to be mediated by sequences located at the N terminus of p36. It was also shown that recruitment of Vp23A to mitochondria by p36 does not require the Ubiquitin E2 Variant domain of Vps23A, which is in contrast to recruitment of ESCRT by retroviruses during viral budding in mammalian cells. Taken together, these results support the hypothesis that CIRV recruits ESCRT by a novel mechanism in order to carry out its replication, a finding that may lend important insight to aspects of normal ESCRT function in plants.
179

Selling Green: Agri-Environmental Certifications in Ontario

Bell, Dana 24 May 2013 (has links)
Utilizing a multiple account benefit-cost framework, this paper will identify and examine three different types of certifications in Ontario: market-driven, regulatory and voluntary. These three types of certification will provide the basis for the analysis of the distribution of benefits and costs in certification programs in the following three case studies: Local Food Plus, Canadian Quality Milk and the Canada- Ontario Environmental Farm Plan. From farmer to fork, the benefits and costs of certifications will be analyzed and best practices from these case studies will be identified. Indicators for success in certifications and recommendations for application in Ontario will be explored. / University of Guelph/ Ontario Ministry of Agriculture, Food and Rural Affairs Research Program
180

Novel Models and Mechanisms in the Neurobiology of Anxiety

Yeung, Michelle Unknown Date
No description available.

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