91 research outputs found

    Intensifying Melbourne

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    Cities are often said to be the engines of the global economy in an age of rapid urbanization. Car-dependent cities - particularly those that characterize North America and Australasia - are largely cities of suburban sprawl, freeways, shopping malls and poor public transport. They are also cities of great opportunity for significant reductions in carbon emissions through transit-oriented intensification within existing suburbs combined with improvements to transit services and shifts to active modes of transport. Such development,however, depends on a multi-scalar understanding that links the shaping of built form and public space at an urban design scale to larger scales of metropolitan structure and urban flows. This research project is an investigation of how such urban design and transport opportunities might be developed in Melbourne. We seek to show how transit-related problems and opportunities at different scales interconnect to form synergies and alliances both between projects and between scales. Through a series of design research studies we explore scenarios for the transformation of suburban railway stations, tram corridors, private shopping malls, university campuses and post-industrial zones. The analysis is undertaken within a theoretical framework of self-organization, emergence, complexity, adaptation and assemblage. Design research at every scale is argued to be a necessary link in the process of unlocking capacities for urban transformation

    Complex array of endobionts in Petalomonas sphagnophila, a large heterotrophic euglenid protist from Sphagnum-dominated peatlands

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    Petalomonas sphagnophila is a poorly studied plastid-lacking euglenid flagellate living in Sphagnum-dominated peatlands. Here we present a broad-ranging microscopic, molecular and microspectrophotometric analysis of uncultured P. sphagnophila collected from four field locations in Nova Scotia, Canada. Consistent with its morphological characteristics, 18S ribosomal DNA (rDNA) phylogenies indicate that P. sphagnophila is specifically related to Petalomonas cantuscygni, the only other Petalomonas species sequenced to date. One of the peculiar characteristics of P. sphagnophila is the presence of several green-pigmented particles ~5ā€‰Ī¼m in diameter in its cytoplasm, which a previously published study suggested to be cyanobacterial endosymbionts. New data presented here, however, suggest that the green intracellular body may not be a cyanobacterium but rather an uncharacterized prokaryote yet to be identified by molecular sequencing. 16S rDNA library sequencing and fluorescence in situ hybridizations show that P. sphagnophila also harbors several other endobionts, including bacteria that represent five novel genus-level groups (one firmicute and four different proteobacteria). 16S rDNA phylogenies suggest that three of these endobionts are related to obligate intracellular bacteria such as Rickettsiales and Coxiella, while the others are related to the Daphnia pathogen Spirobacillus cienkowskii or belong to the Thermoactinomycetaceae. TEM, 16S rDNA library sequencing and a battery of PCR experiments show that the presence of the five P. sphagnophila endobionts varies markedly among the four geographic collections and even among individuals collected from the same location but at different time points. Our study adds significantly to the growing evidence for complex and dynamic protistā€“bacterial associations in nature
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