Bibliography: leaves 169-178.

Le Comité interrégional pour le transport des marchandises (2002) révèle que dans la région de Montréal, une énorme pression s'exerce de plus en plus sur le réseau routier entraînant une congestion chronique de plusieurs axes autoroutiers durant les périodes de pointe du matin et du soir. Les temps de congestion s'allongent sans cesse exacerbant d'autant les effets pervers des multiples retards. Cette situation représente une menace pour la viabilité et la compétitivité tant de l'industrie du transport des marchandises que des autres industries qui comptent sur elle. Pour mettre plus de lumière sur ce sujet, nous avons élaboré cette étude qui représente un diagnostic assez complet de la situation. Au début, nous avons constitué une revue de la littérature exhaustive mettant en relief l'évolution de ce phénomène dans les métropoles contemporaines, les causes qui sont à son origine ainsi que ses impacts sur l'industrie de camionnage. La revue de littérature propose, également, certaines solutions, permettant de résoudre ce problème, qui ont été soulignées par les études antérieures. Par la suite, nous avons établi notre cadre de travail ainsi que nos objectifs de recherche. Pour vérifier nos hypothèses de recherche, nous avons mené un sondage (questionnaire) auprès des compagnies de transport routier de marchandises qui constituent les parties prenantes les plus touchées par ce phénomène. Les résultats obtenus nous confirment qu'effectivement le problème de la congestion routière préoccupe, de plus en plus, les transporteurs routiers de marchandises dans la région de Montréal. Nous avons conclu, également, que ce fléau urbain impose à ces compagnies des surcoûts financiers (surconsommation du carburant et pertes de temps de travail) et des contraintes logistiques (ruptures de stocks et variabilité des temps de livraison). En dernier lieu le présent travail nous permet de faire la distinction entre deux types de solutions: le premier groupe concerne des actions, acceptées par les camionneurs, moins coûteux et moins exigeantes sur le plan logistique (livraisons en dehors des périodes congestionnées, coopération et collaboration entre les parties prenantes) et alors que le deuxième groupe se compose des solutions rejetées par ces acteurs et qui sont plus coûteuses et très exigeantes (délocalisation des entrepôts-terminaux, changement du parc de véhicules).

Le but de ce mémoire est de traiter des déterminants de la valeur dans le marché immobilier montréalais. C'est une étude de cas appliquée aux types de réseaux de distribution câblés, à la végétation et aux types de rue. Cette étude porte sur deux modèles économétriques distincts. Le premier est un modèle de détermination du prix des habitations. Le second est un modèle sur les déterminants de l'erreur d'évaluation. Ce mémoire est une analyse empirique portant sur 2946 condos localisés sur l'île de Montréal et sur l'île des Sœurs. L'originalité de ce document réside dans son sujet, dans les méthodes utilisées pour le traiter et dans les résultats qui ont été obtenus. Comme ce sujet a été déjà grandement couvert par la documentation, nous ne traitons pas ici de l'impact des lignes à haute tension sur la valeur des propriétés. Nous traitons de l'impact des lignes de distribution aux propriétés, qu'elles soient aériennes, en réseaux mixtes ou enfouies. Nous avons, à cet effet, utilisé le système de classement de la Commission des services électriques de la Ville de Montréal. Aucune prime de valeur n'est accordée pour la présence d'un réseau de distribution enfoui. En revanche, une prime de l'ordre de 3,12 % est liée aux propriétés desservies par un réseau de distribution complètement aérien. Nous nous intéressons aussi à l'impact de la végétation sur nos deux modèles. Nous avons, en conséquence, construit un indice de végétation fondé sur la canopée des arbres visible sur les photos aériennes de la Ville de Montréal. Nous avons constaté que doubler la canopée des arbres, soit une hausse de 100 % de la végétation dans un rayon de 75 mètres des bâtiments, entrainera une prime de 2,90 % sur la valeur des condos. Pour finir, nous nous sommes intéressés à l'impact du type de rue sur la valeur des condos. Nous avons utilisé la classification des artères de la Communauté urbaine de Montréal afin d'y parvenir. Ce système de classification nous a permis de constater que plus une rue est passante, moins les gens sont prêts à payer pour y vivre. L'analyse de l'impact de ces variables a aussi été faite sur un modèle de détermination des erreurs d'évaluation. Dans ce modèle, la surévaluation municipale systématique, présente dans notre échantillon, est diminuée avec l'augmentation de la végétation. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : analyse hédonique, immobilier, prix, électrique, rue, arbres, réseaux.

A comprehensive analysis of midlatitude intraseasonal variability in extended integrations of General Circulation Models (GCMs) developed at the National Aeronautics and Space Administration Goddard Space Flight Center is conducted in the first part of this thesis. The model statistics, three-dimensional structure, and dynamical characteristics of storm tracks and large-scale weather regimes are diagnosed and directly compared to parallel observational analyses. Results indicate that several aspects of simulated intraseasonal phenomenon are linked to errors in the zonally asymmetric circulation. During the boreal winter, anomalously large meridional temperature gradients and enhanced zonal winds in the simulations are linked to suppressions in baroclinic wave activity in the models. As a result lower-frequency modes in the GCMs are more strongly driven by baroclinic dynamics. Nonetheless, the GCMs successfully reproduce the North Pacific midwinter suppression phenomenon. In an effort to provide insight into the North Pacific midwinter suppression, the second part of this work stratifies the boreal cool season into three stages, where the early and late (middle) stages approximately correspond to the seasonal maxima (minimum) in synoptic eddy activity that occurs over the North Pacific. Analyses using this unique approach reveal that during the midwinter suppression period, cyclonic perturbations entering the North Pacific storm track core from Asia are already deficient in magnitude compared to early and late winter stages. In both observations and model simulations, the North Pacific midwinter suppression feature is discovered to have a clear organized extension upstream into Siberia. Thus, the final portion of this thesis examines the causes for the midwinter suppression of upper tropospheric Rossby wave packets propagating across Asia prior to entering the North Pacific storm track. The study unveils an increased sensitivity of synoptic-scale wave packets with a large-scale, upper-tropospheric flow pattern over Siberia during midwinter. This interaction with the large-scale pattern over Siberia results in a general dampening of synoptic eddy amplitudes over Asia, which is proposed to be the contributing factor to the North Pacific midwinter suppression phenomenon.

In pregnancy, the maternal cardiovascular and placental circulation undergoes structural and functional changes to accommodate the growing fetus, but the mechanisms involved are not fully understood. Nitric oxide (NO) increases in normal pregnancy and lack of NO has been implicated in pregnancy related complications, preeclampsia and fetal growth restriction. Thus, the objective of the thesis was to determine if cardiovascular, uteroplacental and fetoplacental changes observed in human pregnancy also occur in mice and to assess the obligatory role of eNOS in mediating these changes. I showed that like humans, mice exhibit increases in maternal cardiac output, stroke volume, plasma volume, and uterine arterial blood flow, and a transient decrease in arterial pressure during pregnancy. Importantly, I showed that endothelial nitric oxide synthase (eNOS) plays an important role in promoting the progressive increase in maternal cardiac chamber dimensions and output and the enlargement of the aorta during pregnancy in mice. Another novel finding was that eNOS plays an important role in remodeling of the uterine and umbilical vasculatures during pregnancy. The remodeling of the uterine vasculatures, including the uterine and spiral arteries, were blunted in the eNOS KO mice with ko fetuses (KO(ko)) and this likely contributed to elevated vascular resistance and reduced perfusion of the uterine circulation during pregnancy. Impaired spiral artery remodeling may be caused by a deficiency in decidual uterine natural killer cells. Fetal placental vascularization was also impaired in eNOS KO(ko) mice, which likely increased vascular resistance and thereby reduced fetoplacental perfusion. Reduced vascularization may be due to decreased VEGF mRNA and protein expression in KO(ko) placentas. Decreased perfusion in both the uterine and umbilical circulations most likely contributed to elevated placental and fetal hypoxia in the eNOS KO(ko) mice. Interestingly, despite placental hypoxia, eNOS KO(ko) mice do not show the classical signs of preeclampsia including hypertension and proteinuria nor are maternal plasma sFlt1 levels elevated. Nevertheless, eNOS KO(ko) pups are growth restricted at term, and this is mainly due to the fetal genotype. These findings suggest that eNOS plays an essential role during pregnancy in remodeling of the maternal heart, aorta, and uterine and umbilical vasculatures thereby augmenting blood flow to the maternal and fetal sides of the placenta and thereby promoting fetal growth in mice.

In pregnancy, the maternal cardiovascular and placental circulation undergoes structural and functional changes to accommodate the growing fetus, but the mechanisms involved are not fully understood. Nitric oxide (NO) increases in normal pregnancy and lack of NO has been implicated in pregnancy related complications, preeclampsia and fetal growth restriction. Thus, the objective of the thesis was to determine if cardiovascular, uteroplacental and fetoplacental changes observed in human pregnancy also occur in mice and to assess the obligatory role of eNOS in mediating these changes. I showed that like humans, mice exhibit increases in maternal cardiac output, stroke volume, plasma volume, and uterine arterial blood flow, and a transient decrease in arterial pressure during pregnancy. Importantly, I showed that endothelial nitric oxide synthase (eNOS) plays an important role in promoting the progressive increase in maternal cardiac chamber dimensions and output and the enlargement of the aorta during pregnancy in mice. Another novel finding was that eNOS plays an important role in remodeling of the uterine and umbilical vasculatures during pregnancy. The remodeling of the uterine vasculatures, including the uterine and spiral arteries, were blunted in the eNOS KO mice with ko fetuses (KO(ko)) and this likely contributed to elevated vascular resistance and reduced perfusion of the uterine circulation during pregnancy. Impaired spiral artery remodeling may be caused by a deficiency in decidual uterine natural killer cells. Fetal placental vascularization was also impaired in eNOS KO(ko) mice, which likely increased vascular resistance and thereby reduced fetoplacental perfusion. Reduced vascularization may be due to decreased VEGF mRNA and protein expression in KO(ko) placentas. Decreased perfusion in both the uterine and umbilical circulations most likely contributed to elevated placental and fetal hypoxia in the eNOS KO(ko) mice. Interestingly, despite placental hypoxia, eNOS KO(ko) mice do not show the classical signs of preeclampsia including hypertension and proteinuria nor are maternal plasma sFlt1 levels elevated. Nevertheless, eNOS KO(ko) pups are growth restricted at term, and this is mainly due to the fetal genotype. These findings suggest that eNOS plays an essential role during pregnancy in remodeling of the maternal heart, aorta, and uterine and umbilical vasculatures thereby augmenting blood flow to the maternal and fetal sides of the placenta and thereby promoting fetal growth in mice.

Previous numerical and theoretical results based on constant diapycnal diffusivity suggested the abyssal meridional overturning circulation (MOC) should weaken as winds over the Southern Ocean intensify. We corroborate this result in a simple ocean model, but find it does not hold in more complex models. First, models with a variable eddy transfer coefficient and simple yet dynamic atmosphere and sea-ice models show an increase, albeit slightly, of the abyssal MOC under increasing winds. Second, the abyssal MOC significantly strengthens with winds when diapycnal diffusivity is parameterized to be energetically supported by the winds. This tests the emerging idea that a significant fraction of the wind energy input to the large-scale ocean circulation is removed by mesoscale eddies and may then be transferred to internal lee waves, and thence to bottom-enhanced diapycnal mixing. A scaling theory of the abyssal MOC is extended to incorporate this energy pathway, corroborating our numerical results. / Graduate / 0415 / gstanley@uvic.ca

Graduation date: 2000

Ocean circulation changes in the tropical Pacific strongly influence global climate, as demonstrated during El Niño-Southern Oscillation (ENSO) extremes. Understanding the causes of past variability in tropical Pacific circulation and their relationship to climate change will help to predict how future climate may evolve under anthropogenic radiative forcing. I measure fossil coral radiocarbon (Δ¹⁴C) from Palmyra (6°N, 162°W) and Christmas (2°N, 157°W) Islands in the central tropical Pacific to reconstruct high-resolution records of tropical Pacific ocean circulation variability over the last millennium. Variations in coral Δ¹⁴C from Palmyra and Christmas reflect a combination of the atmospheric concentration of ¹⁴C at the time of growth, Δ¹⁴C-depleted waters associated with equatorial upwelling, and Δ¹⁴C -enriched waters advected from the western tropical Pacific. Existing oxygen isotopic (δ ¹⁸O) records of the Palmyra and Christmas fossil corals reveal a rich history of interannual to centennial variability in sea-surface temperature (SST) and salinity over the last millennium [Cobb et al., 2003b]. My approach targets specific time intervals associated with strong interannual to centennial-scale coral δ ¹⁸O anomalies for high-resolution Δ¹⁴C analysis. Seasonally-resolved Δ¹⁴C measurements are used to compare interannual Δ¹⁴C variability across the 10th, 13th, 15th, 17th, and 20th centuries. Annually-resolved Δ¹⁴C measurements are used to compare decadal to centennial-scale Δ¹⁴C variations from the 10th, 12th - 15th and 17th centuries. SEM photos are used to assess the fidelity of the coral Δ¹⁴C records with respect to post-depositional alteration of the coral skeleton. I find evidence for minor dissolution and addition of secondary aragonite, but my results indicate that coral Δ¹⁴C is only compromised after moderate to severe diagenesis. Despite strong ENSO signals in modern and fossil coral δ ¹⁸O, our data show no statistically significant interannual variability in coral ¹⁴C. There is a centennial-scale increase in coral radiocarbon from the Medieval Climate Anomaly (MCA, ~900-1200AD) to the Little Ice Age (LIA, ~1500-1800). I use a box model of central tropical Pacific Δ¹⁴C contributions to show that this centennial-scale trend over the last millennium is largely explained by centennial-scale changes in atmospheric ¹⁴C. However, large 12th century depletions in Palmyra coral ∆¹⁴C data cannot be explained by atmospheric ¹⁴C variability and likely reflect a roughly two-fold increase in upwelling and/or a significant change in the ¹⁴C of higher-latitude source waters reaching the equatorial Pacific during this time. Conversely, significantly enriched Christmas coral ∆¹⁴C values during the 16th century are consistent with a two-fold reduction in upwelling strength and/or the advection of high-¹⁴C waters to the equatorial thermocline from higher latitudes.

Bibliography: leaves 169-178 / iv, 201 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1989