Satellite Monitoring of Urban Sprawl and Assessment of its Potential Environmental Impact in the Greater Toronto Area Between 1985 and 2005

This research investigates urban sprawl in the Greater Toronto Area (GTA) between 1985 and 2005 and the nature of the resulting landscape fragmentation, particularly with regard to the Oak Ridges Moraine (ORM), an ecologically important area for the region. Six scenes of Landsat TM imagery were acquired in summer of 1985, 1995, and 2005. These images and their texture measures were classified into eight land cover classes with very satisfactory final overall accuracies (93–95?%). Analysis of the classifications indicated that urban areas grew by 20?% between 1985 and 1995 and by 15?% between 1995 and 2005. Landscape fragmentation due to spatio-temporal land cover changes was evaluated using urban compactness indicators and landscape metrics, and results from the latter were used to draw conclusions about probable environmental impact. The indicator results showed that urban proportions increased in nearly all areas outside of the metropolitan center, including on portions of the ORM. The landscape metrics reveal that low density urban areas increased significantly in the GTA between 1985 and 2005, mainly at the expense of agricultural land. The metric results indicate increased vulnerability and exposure to adverse effects for natural and semi-natural land cover through greater contrast and lowered connectivity. The degree of urban perimeter increased around most environmentally significant areas in the region. Changes like these negatively impact species and the regional water supply in the GTA. Further investigation into specific environmental impacts of urban expansion in the region and which areas on the ORM are most at risk is recommended.     

Measuring dissolved organic carbon δ13C in freshwaters using total organic carbon cavity ring-down spectroscopy (TOC-CRDS)

This article reports the first application of coupled total organic carbon cavity ring-down spectroscopy (TOC-CRDS) for the analysis of the ??¹³C signature of dissolved organic carbon (DOC) in freshwater samples. DOC represents a major, dynamic component of the global carbon cycle. The export of DOC from soils into rivers and groundwaters may be highly climate sensitive, and much of this export may occur in ephemeral fluxes. Thus, a robust, simple and inexpensive method for the continuous determination of DOC concentration and quality is urgently needed. We detail recent advances made in the analysis of the ??¹³C signature of DOC using a TOC-CRDS system optimised for the analysis of DOC with natural abundances greater than 2.5?mg?L^?1 with no sample pre-concentration required and sample volumes of 40?mL. Precision between replicated samples was comparable to conventional analysis by gas-source isotope ratio mass spectrometry, yielding ??¹³C values with standard deviations of?±?0.5??? for DOC concentrations higher than 1.5?mg?L^?1. The utility of this technique for the analysis of DOC in samples with a broad range of compositions and concentrations (2.5?C25?mg?L^?1 DOC) is demonstrated. Since DOC ??¹³C can be measured continuously, ca. 45?min per measurement, this method enables the online monitoring of DOC in river water, water intakes and treated waters, allowing changes in DOC fluxes to be monitored in real time.     

Outcome of cases of de novo structural rearrangements diagnosed at amniocentesis

The frequency of de novo rearrangements at amniocentesis was determined in 76952 prenatal diagnoses from centres in the United States. Rates for balanced rearrangements are slightly greater than rates previously reported in the newborn, possibly because banding studies were not used in the latter. Rates for unbalanced rearrangements are considerably higher in the amniocentesis data not only because banding was used but also because a substantial loss of abnormal conceptions is to be expected between amniocentesis and birth. The higher frequency of cases with supernumerary markers at amniocentesis is unexplained. A review of 66 apparently balanced de novo rearrangements found at amniocentesis revealed evidence of abnormality in five; in four of these the abnormality was noted in the abortus. The number of cases observed is still too small to rule out a risk of abnormality no greater than the usual rate of abnormalities at birth. Abnormalities were detected in 6 of 10 cases with unbalanced de novo rearrangements. In 33 cases of non-familial supernumerary chromosomes 6 (18.2 per cent) showed abnormality. Non-satellited markers appeared to have a higher rate of abnormality than satellited markers but the difference is not statistically significant. Further studies and improved follow-up of de NOVO cases diagnosed at amniocentesis are required.     

A framework for profiling a lake's riparian area development potential

Some of the greatest challenges for managing residential development occur at the interface between the terrestrial and aquatic ecosystems--in a lake's riparian area. Land use planners need a framework they can use to identify development hotspots, areas were the next push for development will most likely occur. Lake riparian development profiles provide a framework for linking ecological and social factors important to development. In a test of this framework in northern Minnesota, researchers identified seven constructs influencing riparian area development: current general development, current housing development, and availability, accessibility, suitability, aesthetics, and proximity to services. Profiles display a lake's value for each construct relative to the range of values for all lakes in the county. Maps, developed using indicators for several constructs, allow us to identify how the factors interact and are dispersed across the landscape. These profiles help policy makers, planners, and managers identify lakes that are potential development hotspots so they can take timely steps to manage development or control the impacts of development.     

Dynamic exchange of gaseous elemental mercury during polar night and day

From February 29 until June 15 2008 gaseous elemental mercury (GEM) fluxes above a snow covered surface was measured in Ny-Ålesund, Svalbard using a GEM flux gradient method. A clear seasonal pattern in the meteorological variables associated with the GEM flux was observed. For the first time in Ny-Ålesund a net deposition of GEM was recorded during polar night, despite the lack of Atmospheric Mercury Depletion Events (AMDE). 7500 ng m⁻² GEM was emitted from the surface snow to the air during the entire study. The depositions of GEM and reactive gaseous mercury (RGM) were calculated to be 1500 and 1000 ng m⁻², respectively, during the same time period. The GEM fluxes reported in this study were found to be comparable to GEM fluxes measured at other Arctic locations (i.e. Alert and Barrow), suggesting that GEM acts in a similar way throughout the Arctic. An assessment of the GEM flux gradient method used discovered a non-linear GEM concentration profile. The nonlinearity was explained by a non-stationary turbulence regime. The GEM flux calculated was not found to be representative for the entire surface boundary layer.     

Adolescent, and their parents, attitudes towards graduated driver licensing and subsequent risky driving and crashes in young adulthood

Problem

Although Graduated Driver Licensing Systems (GDLS) have helped reduce young driver crash rates, they remain significantly over-represented in crash statistics. To be effective GDLS rely heavily on support for the legislation by those directly involved; parents to enforce the restrictions and adolescents to comply. There is some evidence that practices regarding GDLS restrictions influence adolescent driving outcomes in the early stage of licensure. However there has been no examination undertaken on the influence of parent and adolescent attitudes toward GDLS on adolescents’ driving behavior and crash experiences as they move into their young adult years. The aim of this research was to examine these relationships.

Method

This investigation was based on a longitudinal study of a birth cohort, and uses data collected when the cohort members were aged 15, 18, and 21 years. At age 15 both adolescent and their parent attitudes toward GDLS were measured. At age 18 adolescent GDLS attitudes were measured again. The association between these measures and self-reported risky driving behavior and crash involvement at age 21 were examined.

Results

Negative attitudes toward the learner supervisor restriction for males, and negative attitudes toward a GDLS for females were strongly associated with risky driving and crash involvement as young adults.

Impact on industry

Targeting interventions to improve adolescents and parents understanding of the reasons for graduated licensing and the specific restrictions may improve attitudes and views and thereby contribute to a reduction in risky driving behaviors and crash risk among young adults.