No description available.

I compared understorey communities under Alnus viridis ssp. crispa (Ait.) Pursh (green alder) and Corylus cornuta Marsh. (beaked hazel) in two boreal jack pine forests. There was no difference in inorganic soil nitrogen, but alder plots had lower species richness at Star Lake and higher evenness in the Sandilands. I incubated chopsticks and litterbags containing natural litter assemblages underneath A. crispa and C. cornuta in the field, and litterbags containing artificial litter mixes in a dark growth chamber. There was no significant difference between treatments for litterbags or chopsticks in the field, nor between mixes with or without alder in the growth chamber.

No description available.

A methodology for the synthesis of substituted pyridines via Diels-Alder condensation of N-(O-tbutyldimethylsilyloxy)-3-methyl-l-aza-1,3-butadiene (65) and N-(O-tbutyl dimethylsilyloxy)-2-methyl-l-aza-1,3-butadiene (66) with substituted 1,4-benzoquinones was developed.The novel azadienes 65 and 66 were synthesized by direct condensation of N-(Otbutyldimethylsilyloxy) hydroxylamine with methacrolein and methyl vinyl ketone respectively. The azadiene 66 was also prepared by condensation of N-(O-tbutyldimethylsilyloxy) hydroxylamine with 3-bromo-2-butanone followed by dehydrohalogenation of the resulting imine with potassium tbutoxide.The Diels-Alder condensation of 66 with N-phenylmaleimide produced N-phenyl-6methyl-2,3-pyridinedicarboximide (82). The [4+2] cycloaddition of 66 with Nphenylmaleimide, naphthoquinone, 2-acetamido-5-bromo- and 2-acetamido-6-bromo-1,4benzoquinone, 2,6-dichloro-1,4-benzoquinone, 2-bromo- 1,4-benzoquinone resulted in the formation of N-phenyl-5-methyl-2,3-pyridinedicarboximide (83), 3-methyl-lazaanthracene-9,10-dione (87), 6-acetamido-3-methylquinoline-5,8-Dione (90), 7acetamido-3-methylquinoline-5,8-dione (91), 7-chloro-3-methylquinoline-5,8-dione (93), 3-methylquinoline-5,8-dione (95) respectively. Diels-Alder condensation of 2,6-dibromo 1,4-benzoquinone with azadienes 65 and 66 produced some non-isolable tar. Total synthesis of 7-bromolavendamycin methyl ester 33 was also attempted. Although all attempts to obtain the key intermediate, 7-bromo-2-methyl-5,8-quinolinedione (98a), either from the Diels-Alder condensation of 66 or oxidation of 5,7-dibromo-2-methyl-8hydroxy quinoline (99) failed, 98a was synthesized through oxidation of 5-amino-7bromo-2-methyl-8-hydroxyquinoline (104). Selective oxidation of 98a with SeO2 produced 7-bromo-2-formylquinoline-5,8-dione (98b). Pictet-Spengler condensation of 98b with p-methyl trypthophan methyl ester (55), gave the tetrahydrocarboline 106 which was decomposed in refluxing benzene.In a different pathway, 103 was selectively oxidized to 7- bromo-2- form yl -5-ni tro8-hydroxyquinoline (107b). Condensation of this aldehyde with p-methyl tripthophan (55), produced 3-carbomethoxy-4methyl-l-(7-bromo-8-hydroxy-5-nitro-2-quinolinyl)-(3carboline (109a). 3-Carbomethoxy-4-methyl-l-(7-bromo-8-hydroxy-5-amino-2quinolinyl)-p-carboline (109b) was obtained by reduction of 109a. It is expected that 7bromolavendamycin methyl ester 33 to be produced by oxidation of 109b.The structures of the new compounds were confirmed by NMR, IR and mass spectroscopy as well as the elemental analysis. All the spectra are included at the end of this thesis for further reference. / Department of Chemistry

I compared understorey communities under Alnus viridis ssp. crispa (Ait.) Pursh (green alder) and Corylus cornuta Marsh. (beaked hazel) in two boreal jack pine forests. There was no difference in inorganic soil nitrogen, but alder plots had lower species richness at Star Lake and higher evenness in the Sandilands. I incubated chopsticks and litterbags containing natural litter assemblages underneath A. crispa and C. cornuta in the field, and litterbags containing artificial litter mixes in a dark growth chamber. There was no significant difference between treatments for litterbags or chopsticks in the field, nor between mixes with or without alder in the growth chamber.

The circumpolar Arctic is experiencing dramatic environmental changes that are already impacting tundra ecosystems and northern communities that are intimately linked to the land. Increasing permafrost degradation, shrub encroachment, larger and more frequent fires, and increasing human development have significant effects on biotic and abiotic conditions in the lower Peel River watershed, NT. To understand and respond to rapid environmental changes, diverse knowledge perspectives are needed, so my M.Sc. research uses scientific and social scientific approaches to investigate environmental change in the lower Peel River watershed. I investigated the impacts of the Dempster highway on plants, soils and permafrost in the Peel Plateau by conducting field surveys at sites dominated either by tall alder (Alnus crispa) shrubs or by dwarf shrubs, at 30 m and 500 m from the highway. At each site I measured vegetation composition, alder growth, soil nutrients, litter and organic layer thickness, active layer thickness, and snow depth. We found that alder growth and recruitment were enhanced adjacent to the Dempster Highway, and dramatic alterations to plant community composition, soil properties and ground temperatures were observed where alder shrubs had formed closed canopies. Tall shrub sites adjacent to the road exhibited lower abundance of understory vegetation including mosses, greater litter and organic soil thickness, higher nutrient availability, and deeper snowpack. Biotic and abiotic changes associated with road effects feedback with alder canopy development, and have important implications for permafrost conditions adjacent to the roadbed, and potentially on road bed performance. This research contributes to our understanding of environmental changes caused by the highway and their consequences for infrastructure stability and pan-Arctic changes in vegetation cover. In a separate but complementary effort, I worked with Teetl’it Gwich’in land users and youth from Fort McPherson, NT to map observations of environmental conditions and changes. In the pilot year of a community-based environmental monitoring program, we employed participatory multimedia mapping with Teetl’it Gwich’in land users and youth from Fort McPherson, NT. I accompanied Gwich’in monitors on trips on the land to document environmental conditions and changes. Observations made by land users were documented using photos, videos and audio taken by youth, and land users provided detailed information about each observation in follow-up interviews. I compiled observations (photo/video, GPS location, and interview audio and transcript) into a web-based map where the public will be able to see changes on the land in the images and words of Gwich’in land users. The online map will provide a medium for local residents to communicate their knowledge and concerns about the environment, and will be useful for land management and planning, environmental monitoring, and adaptation. / Graduate / 0768 / 0329 / 0326 / hkgill@uvic.ca

Thesis (Ph. D.)--Virginia Polytechnic Institute, 1955. / Vita. Abstract. Includes bibliographical references (leaves 266-285). Also available via the Internet.

Thesis (M.S.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 87-92). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 248-257). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1989. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.