Characteristics of minke whale (Balaenoptera acutorostrata) habitat at the head of the Laurentian Channel in the St. Lawrence Estuary, Canada were identified by quantifying environmental and temporal habitat variables and comparing them to the presence or absence of minke whales during the summer of 1996. Identification photographs of minke whales taken during the summers of 1995 and 1996 were used to examine intra-annual and year to year habitat use by individual minke whales. Minke whales were primarily distributed between the 50 m and 100 m bathymetric contours which corresponds to the ridge of the Laurentian Channel. This region is characterized by a steep slope in bottom topography which causes predictable accumulations of euphausiids and capelin (Mal lotus villosus), the principal prey species of minke whales. Tide phase, lunar phase and time of season, all of which cause slight fluctuations in prey abundance did not appear to have a significant influence on minke whale presence or movements. Individual minke whales exhibited site tenacity in returning to a localized area both within a season and in consecutive years. / Graduation date: 1999

Major depressive disorder is a common severe psychiatric disorder with unknown etiology. Recent studies show that the loss and malfunction of oligodendrocytes are closely related to the neuropathological changes in depression, which can be reversed by antidepressant treatment. St. Johns wort is an effective and safe herbal treatment for depression in several clinical trials. However, the underlying mechanism of its therapeutic effects is unclear. In this study, we evaluated the effects of hyperforin, a major active component of this herb, on the proliferation, mitochondrial function and development of oligodendrocytes. We have demonstrated that hyperforin increases mitochondrial function and prevents mitochondrial toxin-induced cytotoxicity in oligodendrocyte lineage cells. Hyperforin promotes the maturation of oligodendrocytes but does not increase the proliferation of oligodendrocyte progenitor cell line and neural stem/progenitor cells. Our findings suggest that chronic hyperforin treatment may stimulate the development and function of oligodendrocytes. These results suggest a new mechanism of hyperforin in depression treatment. Future in vitro and in vivo studies are required to further characterize the mechanisms of hyperforin.

Multiresolution analysis (MRA) has fairly recently become important, and even essential, to image processing and signal analysis, and is thus having a growing impact on image and signal related areas. As one of the most famous family members of the MRA, the wavelet transform (WT) has demonstrated itself in numerous successful applications in various fields, and become one of the most powerful tools in the fields of image processing and signal analysis. Due to the fact that only the scale information is supplied in WT, the applications using the wavelet transform may be limited when the absolutely-referenced frequency and phase information are required. The Stockwell transform (ST) is a recently proposed multiresolution transform that supplies the absolutely-referenced frequency and phase information. However, the ST redundantly doubles the dimension of the original data set. Because of this redundancy, use of the ST is computationally expensive and even infeasible on some large size data sets. Thus, I propose the use of the discrete orthonormal Stockwell transform (DOST), a non-redundant version of ST. This thesis will continue to implement the theoretical research on the DOST and elaborate on some of our successful applications using the DOST. We uncover the fast calculation mechanism of the DOST using an equivalent matrix form that we discovered. We also highlight applications of the DOST in image compression and image restoration, and analyze the global and local translation properties. The local nature of the DOST suggests that it could be used in many other local applications.

Major depressive disorder is a common severe psychiatric disorder with unknown etiology. Recent studies show that the loss and malfunction of oligodendrocytes are closely related to the neuropathological changes in depression, which can be reversed by antidepressant treatment. St. Johns wort is an effective and safe herbal treatment for depression in several clinical trials. However, the underlying mechanism of its therapeutic effects is unclear. In this study, we evaluated the effects of hyperforin, a major active component of this herb, on the proliferation, mitochondrial function and development of oligodendrocytes. We have demonstrated that hyperforin increases mitochondrial function and prevents mitochondrial toxin-induced cytotoxicity in oligodendrocyte lineage cells. Hyperforin promotes the maturation of oligodendrocytes but does not increase the proliferation of oligodendrocyte progenitor cell line and neural stem/progenitor cells. Our findings suggest that chronic hyperforin treatment may stimulate the development and function of oligodendrocytes. These results suggest a new mechanism of hyperforin in depression treatment. Future in vitro and in vivo studies are required to further characterize the mechanisms of hyperforin.

In this study, we use the reactive rf magnetron sputtering method with deposition parameters of RF power of 370W, sputtering pressure of 15 mTorr, substrate temperature of 400¢J, nitrogen concentration (N2/N2+Ar) of 30% and 40%, to deposit highly c-axis orientation AlN thin films on Z-cut LiNbO3 and ST-cut quartz piezoelectric substrate, respectively. The material characteristics of AlN films deposited on Z-cut LiNbO3 and ST-cut quartz substrate with different thickness were obtained by means of the analyses of XRD, SEM and AFM. Besides, the interdigital transducers (IDTs) were fabricated on the bi-layers structure. The AlN film thickness of piezoelectric bi-layers structure was varied in order to discuss its effect on SAW devices and the temperature coefficient of frequency (TCF) of AlN. From the experimental results, it reveals that the center frequency and TCF of SAW filters increase with the increased AlN thin film thickness. Besides it can be concluded that poly-crystalline AlN exhibits a positive temperature coefficient of frequency (TCF).

Texte remanié de: Th.--Stockholm Universitet, 2003. / Bibliogr. p. 351-370.

Dissertation--Universität Erfurt, 2002. / Notes bibliogr.

Thesis (M.M.S.)--Memorial University of Newfoundland, 2000. / Bibliography: p. 58-59.

The St. Elias Orogen is the result of oblique collision and flat-slab subduction in the Gulf of Alaska between North America (NA) and the Yakutat microplate (YAK). Extensive glaciation and a complex tectonic environment make this region a unique case study in which to examine the details of terrane accretion and the possible coupled influence of climate and tectonic drivers on the structural and topographic evolution of an orogenic wedge. The dataset for this project includes: 3 multi-channel seismic reflection surveys (~4000 km total seismic reflection data) and a ~450 km-long wide-angle seismic refraction profile. Reflection seismic profiles across the offshore YAK-NA deformation front, provide constraints for quantifying Pleistocene deformation recorded in the glaciomarine Yakataga formation. Growth strata and kinematic fold analysis allow comparison of relative timing of fault activity, which reveals temporal and spatial shifting of deformation within the margin towards the onshore eastern corner of the orogen. This information is important not only for the development of regional tectonic models, but also for understanding how climatic shifts may have affected the evolution of margin architecture during Pleistocene glacial-interglacial periods. Joint tomographic inversion of coincident reflection and refraction profiles constrains YAK crustal velocity and thickness. The offshore YAK crust ranges in thickness from 15 to 35 km, considerably thicker than normal oceanic crust. The crustal thickness and velocity structure support an oceanic plateau origin for the YAK microplate. Crustal velocity and structure are continuous across the YAK shelf except for a regional dip of the top of YAK crust of ~3° to the west. Moho arrivals across the profile do not mimic the dipping trajectory of the basement, indicating that the offshore YAK crust is doorstop-shaped, thinning in the convergence direction. This geometry leads to the following implications for the YAK-NA collision: first, uplift and deformation have intensified through time as successively thicker, more buoyant YAK crust attempts to subduct; second, current topography, exhumation and deformation patterns are partially controlled by underlying crustal geometry of converging YAK crust. / text

This thesis explores the connections that the Garifuna indigenous group of Belize has with their former homeland, the island of St. Vincent. After emerging as a distinct ethnic group during the 17th century, the Garifuna were exiled from St. Vincent by British colonial rulers in 1797. For the Garifuna people, the connection to the island is more than historical. It is also spiritual. Interviews were conducted in July 2006 in Belize with members of the Garifuna community who have made the journey back to the island. In addition to presenting the results of those interviews, this thesis will also provide a history of the Garifuna people, describe some of the spiritual aspects of the culture, and a discussion of the current literature on pilgrimage.