1,025 research outputs found
Low acetylcholine during early sleep is crucial for motor memory consolidation
I investigated a potential relationship between motor memory and acetylcholine activity during early sleep characterized by slow-wave electroencephalographic activity and reduced cholinergic tone. I tested the hypothesis that altering acetylcholine levels during early sleep would disrupt motor memory consolidation. I trained 93 wild-type and 17 transgenic adult mice on motor tasks either rotarod or skilled-forelimb reach. Immediately after training, I either increased or decreased acetylcholine levels in the subsequent post-learning early sleep. Upon retesting performance on motor tasks, I discovered that increasing acetylcholine levels impaired motor memory consolidation while decreasing acetylcholine levels did not have an effect. I also found a larger involvement of muscarinic acetylcholine receptors compared to nicotinic ones for motor memory consolidation. With filming and electrophysiology, I determined that increasing acetylcholine altered sleep structure and reduced slow-wave activity in early sleep. These results suggest that motor memories are consolidated during slow-wave sleep when cholinergic levels are low
8,893 kilometres of cooperation : applying Kingdon's model to the development of Canadian border security policy since 9/11
vii, 133 leaves ; 29 cmCanadian border security policies are largely shaped by the asymmetrical relationship that exists between Canada and the United States. American markets are the primary destination for over eighty percent of Canadian exports, creating an economic dependence highlighted in the days following 9/11. As wait times at the American border extended to sixteen hours the importance of the shared border came sharply into focus. To ensure Canada‟s economic security the Canadian government needed to develop policies that would satisfy the American need for physical security and the Canadian need for economic security. This thesis applies John Kingdon‟s policy streams model to demonstrate and explain the subsequent development of Canadian border security policies. It also examines the institutional context for border security policies and examines two case studies: the Container Security Initiative and NEXUS
Patterns of habitat use of breeding ducks and grebes in the western boreal forest
xiii, 97 leaves ; 29 cmCanada’s boreal forest provides important breeding habitat for 12 to 14 million migratory birds annually. Nonetheless the ecology of boreal wetlands remains poorly understood. Over the last 40 years, rapid industrial development with little attention to conservation has been ongoing in the region. Apparent population declines of species, such as that of lesser scaup have raised concerns about the quality of western boreal wetlands. This is one of very few studies demonstrating patterns in brood-rearing habitat use by ducks and grebes in the Canadian western boreal forest. In this study, wetland characteristics associated with brood-rearing wetlands of American wigeon (Anas Americana), green-winged teal (Anas crecca), mallard (Anas platyrhynchos), lesser scaup (Aythya affinis), ring-necked duck (Aythya collaris), horned grebe (Pondiceps auritus), and red-necked grebe (Podiceps grisegena) were investigated on 75 wetlands near Yellowknife, NT, Canada.
I used Principle Components and regression analyses to delineate patterns of habitat use by breeding water birds. Results indicate that physical characteristics of wetlands, area in particular, had stronger correlations with brood-rearing habitat then did invertebrate abundance. Invertebrate groups positively associated with brood-rearing wetlands included: Amphipoda, Pelecypoda, and or Ephemeroptera. Breeding diving ducks had negative
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associations with Dipteran abundance. Diving ducks and red-necked grebes were more strongly correlated with habitat variables then were dabbling ducks and horned grebes. Brood-rearing wetlands of the smallest birds in the study, green-winged teal and horned grebe, had the fewest and weakest associations with habitat variables
"I wanna be toned I don't want to be muscular" : dominant discourses and women's exercise choices
vii, 149 leaves ; 29 cmThis thesis explores how women who exercise regularly frame their involvement in
exercise with regard to discourses of femininity, fitness, consumerism, and healthism,
and how these contemporary discourses impact women’s exercise choices. Sixteen semistructured
interviews were conducted with women who exercise regularly. The objective
was to elicit detailed information about the types of exercise these women were involved
in, how they came to exercise in particular ways, and with what rationales. A Foucaultian
discourse analysis of the interview transcripts was undertaken to uncover commonalities
and differences in how the sometimes competing discourses of femininity, fitness,
consumerism, and healthism affect the types of exercise engaged in. By examining the
interplay between discourse, power/knowledge, surveillance, discipline, subjectivity, and
the resultant construction of normative feminine and health ideals, this thesis attempts to
determine how women are constructed, and construct themselves, as regular exercisers
and how this construction impacts the ways in which the women chose to exercise
The role of epigenetic changes in chemoresistant breast cancer cells
xiii, 116 leaves : ill. (some col.) ; 29 cmCytotoxic chemotherapy is extremely important in adjuvant treatment of breast cancer. Yet, tumours frequently acquire chemoresistance that correlates with increased aggressiveness and poor prognosis. Three theories exist describing how the resistance develops: genetic, epigenetic and karyotypic theory. The epigenetic theory is the least explored. Here we analyzed the role of the epigenetic phenomena in the acquisition of drug resistance. To do so, we employed genome wide screens of microRNA and gene expression, DNA methylation and complete genome hybridization. We identified three novel microRNA interactions involved in the chemoresistant phenotype. These three microRNAs displayed depressed expression in the resistant cell lines and we were able to re-establish some level of drug sensitivity through ectopic expression of these under expressed microRNAs. In addition, we described the role of DNA methylation in impacting expression of a wide range of genes, thus, contributing to the phenotype of chemoresistance. Furthermore, we revealed a distorted global DNA methylation pattern that coincides with massive instability of the resistant genome. Finally, our results present a striking similarity between gene expression, epigenetic profiles and chromosomal aberrations in two different drug resistant cell lines. Taken together, this project suggests that the acquisition of chemoresistant phenotype is epigenetic in nature and may arise with a predictable pattern. Elucidating the specifics of this pattern may in the future prove useful in developing treatment and prognostic chemoresistance biomarkers
Community structure of helminth parasites in whitefish from the Caribou Mountains, Alberta
vii, 147 leaves : ill. ; 28 cm.Spatial patterns in parasite communities of freshwater fish are often characterized as low in diversity and unpredictable. Whether or not his view is a true reflection of community patterns is unclear, in particular when comparing studies of parasite communities of fish occuring in man-altered ecosystems. To understand the structure of a fish parasite community, I first described the parasite fauna of 13 species of freshwater fish from 19 isolated lakes on the Caribou Mountains plateau in northern Alberta. After my initial broad-scale survey, I selected the diverse and complex community of parasites in whitefish, (Coregonus clupeaformis) for further analysis. This host had the most diverse parasite community of any species of fish on the plateau and was disproportionally important in the dissemination of parasites to the other species of fish. Ten parasite species infected whitefish in the 7 large lakes on the plateau; 7 were core species (i.e found in every lake) and 9 were salmonid specialists. Parasite intensities were much higher (>100 per host) in the Caribou Mountains than elsewhere in Canada, as was community similarity (>70%). Ordination analyses showed that 48% of the variation in parasite intensities between lakes could be explained by factors associated with aquatic productivity (e.g. chlorophyll-a and total phosphorus). Low-intensity lakes were characterized by low productivity and high colour and high-intensity lakes were characterized by low productivity and high colour and high-intensity lakes had high prductivity and low colour. Patterns of high similarity between lakes, together with the association between aquatic productivity and community structure shows that the spatial structure of parasite communities can be predicted on the basis of a common suite of specialist, core species
Spectroscopic study of the fundamental band of carbon monoxide for atmospheric composition retrievals
Over the past couple of decades, the study of infrared spectra of carbon monoxide has been the subject of interest because of its existence in the Earth’s atmosphere as well in different planetary atmospheres. This work presents a line-shape study transitions of pure carbon monoxide and carbon monoxide mixed with air in the fundamental band, recorded over a temperature range from 79 K to 296 K using a high-resolution Fourier Transform Spectrometer (FTS). In this study, different pressure induced line-shape parameters as well as their temperature dependences have been measured and compared with relevant previous published results. Also, the transformation of line-shapes due to line-mixing and Dicke narrowing effects have been investigated. Two semi-empirical approaches, namely: the Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) approximation have been employed for theoretical calculation of line-mixing coefficients which show good agreement with the measured values.University of Lethbridge, The Natural Sciences and Engineering Research Council of Canada CREATE” “Advanced Methods, Education and Training in Hyperspectral Science and Technology (AMETHYST)
The effects of democracy on National GDP per Capita: an empirical investigation
The growth democracy question has been a subject of fundamental debate for the last few decades. Political regimes seem have been evidently shaping the economic performance, by greatly affecting regulations, enhancing accountability and transparency mechanisms, promoting the well-being of the whole population, and achieving satisfactory performance for the upcoming elections. Hence, this thesis examines the role of democracy in economic growth, by examining its effects on national Gross Domestic Product per Capita (GDPC). It utilizes a novel dataset which includes several democracy variables, such as Representative Government, Fundamental Rights, Checks on Government, and Impartial Administration. We find that the impact of democracy on GDPC is positive and significant. These results come in contrast to lower democracy levels in many emerging markets with relatively high economic growth rates. Finally, the empirical evidence points out that well-established democratic institutions provide economic stability, and they have positive effects on GDPC
"We came to Canada and we were going to make it": oral history, agency, and post-Second World War Dutch immigrant children and adolescents in Alberta
This project reconceptualizes the immigrant child in a way that underscores their experience as distinct from that of an adult. There is little qualitative research on the histories of Dutch child immigrants and the findings in this thesis draw attention to and help fill this gap. By highlighting the life stories of school-aged Dutch children in southern Alberta and focusing on the complexities they faced during integration, there is opportunity to rethink what has been documented about their roles in the family migration process. This thesis shows how post-Second World War child immigrant memories are worthy of exploration as they serve to enrich our understanding of how children exercised agency and demonstrated independent thought while adjusting to unfamiliar cultural and social practices
The fear conditioned response under head fixation
In classic measures of fear induced freezing behavior, animals stop all movement except breathing. Many large-scale recording techniques in modern neuroscience such as wide-field and two-photon fluorescent imaging require animals be in a head-fixed preparation. Here we demonstrate that it is possible to measure freezing behavior in head-fixed mice based on video measurements of motion, the pupillary response, and electromyography of neck muscles. Animals were either conditioned to form an association between a tone (conditioned stimulus; CS) and a footshock (unconditioned stimulus; US) or were presented both tones and footshocks explicitly unpaired. Animals who were conditioned to form an association showed less movement, and a stronger pupil response when presented with the CS. We outline key considerations which are likely important in establishing a strong fear response in a head-fixed preparation
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