Academisch proefschrift - Leiden. / Includes bibliographical references.

Thesis (M. Ed.)--University of Hong Kong, 1983.

No description available.

No description available.

This thesis investigates the nature and distribution of ground ice occurrences on the central Fosheim Peninsula, Ellesmere Island, and assesses the potential for thermokarst in light of possible climatic warming. / Field observations conducted in 1990 and 1991 involved geomorphological and cryostratigraphic examinations of twenty-eight ground ice sections exposed in retrogressive thaw slumps and ground probing radar surveys of two of the thaw slumps. Samples were taken of ground ice and sediments exposed in thaw slump headwalls for laboratory analysis. / Samples were analyzed for moisture content, grain size distribution, and Atterberg limits. Gravimetric ice contents were calculated and an average ice content profile was constructed for the study area. / Ground ice was found to be an important component of permafrost on the Fosheim Peninsula and was widely observed in Holocene marine sediments. The ice occurred in two stratigraphic settings at depths of one to five meters in silt and clay, and at ten meters or deeper beneath massive clay. Ice contents were generally found to increase rapidly with depth down to three meters, below which ice content was stabilized. / Ground probing radar was found to be a useful tool for permafrost research, given its ability to discriminate between ice and soil, as well as between frozen and unfrozen water.

The short-term responses of Cassiope tetragona, a high arctic evergreen shrub, to variations in growing season climate were examined using experimental manipulations of temperature and growing season length at Alexandra Fiord, Ellesmere Island. Surface temperatures in the field were increased an average of 1-2 °C in two communities using open-top greenhouses. Growing season length was altered in a snowbed community by using manual snow manipulations to change the date of snowmelt. Growth and reproductive responses of Cassiope tetragona to these manipulations were observed over two field seasons following treatment establishment. Natural variations in vegetative and reproductive characteristics of Cassiope tetragona were also monitored in unmanipulated communities selected to represent a range of environmental conditions at the study site. Retrospective analysis of past Cassiope growth and reproduction was used to provide a record of variations in productivity spanning 25-35 years which could be related to climate records from Ellesmere Island. For the retrospective analysis, patterns of internode lengths were used to delimit sections of annual growth and chronologies of annual stem elongation, leaf number and flower number were then analyzed using methods similar to those applied to tree-ring studies. In general, the reproductive parameters of Cassiope tetragona were observed to be highly responsive to short-term variations in growing season climate, while vegetative production exhibited a much more conservative response. Flower production and rates of reproductive development were significantly stimulated by experimental warming. Retrospective analysis of flower production support field observations indicating that flower production is highly sensitive to annual variations in growing season temperatures. In contrast, shoot growth showed moderate responses to experimental warming. Records of past growth indicate that although vegetative production appears to be sensitive to annual variations in summer temperatures, the degree of responsiveness is much lower than for reproductive parameters. Net growth and reproduction were not stronly affected by natural or experimental variations in snowmelt timing, although phenology timing was significantly altered. The conservative growth response of Cassiope tetragona to short-term variations in climate is suggested to be related to constraints on plant phenology which may restrict flexibility in the period utilized by plants for aboveground growth. Preferential allocation of within-plant resources to reproductive structures during periods of ameliorated growing season climate may account for the observed strong reproductive responses to climate variations. Trade-offs betweeen growth and reproduction have important implications for predicting the long-term response of Cassiope tetragona to climate change. An understanding of within-plant allocation strategies is also important to the interpretation of past variations in growth and reproduction. Retrospective analysis of past Cassiope production is likely to be a very useful tool for investigating ecological relationships and past climate change.

<p>The major aim of this study is to determine and compare the distribution of bacteria and actinobacteria in Marion Island terrestrial habitats.</p>

No description available.

Urban heat islands (UHIs) are unique phenomena that occur when urban areas experience higher temperatures than surrounding areas. The primary cause of urban heat islands is the absorption of insolation by urban structures that is nocturnally released. UHIs can cause many problems both environmentally and physically (in terms of human health). In 1998, Chicago joined the EPA’s Urban Heat Island Pilot Project (UHIPP), which aims to mitigate the UHI effect in pilot cities throughout the country. Exactly how effective has UHIPP been in reducing Chicago’s UHI effect? This research examines Chicago’s heat island effect from 1997 (pre-UHIPP) to 2007. Observations of surface temperatures, along with hourly historical air temperature data, and population data provide the information needed to investigate Chicago’s UHI effect. Relationships between temperature and land cover as well as temperature and population will give further indication of the influences of the UHI effect. More specifically, hot spot and cool spot analysis, will give Chicago and other cities an idea of the effectiveness of EPA’s UHIPP in reducing urban heat islands. / Department of Geography

This study used thematic analysis to investigate how youth court professionals, namely Youth Court Judges, Youth Probation Officers, and Youth Police Officers, make decisions to incarcerate young females for administrative offences. Sixteen professionals from Lower Vancouver Island shared their experiences through one-on-one interviews, which were then thematically analysed. This method of analysis shed light on four major themes across the professional groups: i) The Youth Criminal Justice Act (2002); ii) Decision-making; iii) The decline in crime; and iv) Services for adjudicated youth. Findings were discussed in relation to the literature and the resources currently available in the community. / Graduate / 0627 / 0398 / 0452 / tamorim@uvic.ca