Astrobiology is a multidisciplinary topic that addresses the origin, distribution and evolution of life in the universe. One of the key questions relates to whether life could have evolved on other planetary bodies, and Mars has been the major focus. Biologists contribute to this question by studying the ecology of extreme environments on Earth that share closest analogy to Mars’ past or present environment. In this thesis, molecular-level interrogations were used to address some aspects of microbial biodiversity, ecology and stress tolerance in two such extreme environments. The high-altitude cold and intense UV irradiance of central Tibet was selected as an analogue for Mars surface today, whilst cold alkaline high-carbonate freshwater lakes were chosen as an analogue for Mars’ previous late wet phase. Biological soil crusts from central Tibet supported a diverse microflora and these were variously bacteria or eukarya dominated. The relatively well-developed eukarya-dominated crusts were characterized and showed they comprised of Stichococcus bacillaris, plus alphaproteobacteria, betaproteobacteria, bacteroidetes and gemmatimonadetes. In order to evaluate the diversity of radiation-tolerant taxa in these soils, samples were exposed to ionizing radiation and viability, physiology and phylogenetic identity determined. The most radio-tolerant taxa isolated and characterized were from the radiation tolerant phylum Deinococci (15kGy), whilst a relatively diverse range of Actinobacteria, Bacilli, Cyanobacteria and Proteobacteria were also recovered after exposure to doses up to 10kGy. This implies the high-radiation environment has selected for tolerance among diverse phyla, with tolerances that far exceed environmental exposure. It is not known at this stage if they all employ similar protective strategies. Microbial reefs that have developed in cold alkaline lakes in British Columbia were studied as analogues for a late-wet Mars environment. Molecular ecological analysis revealed that communities consisted largely of of Proteobacteria (alpha), Cyanobacteria (Leptolyngbya) and Acidobacteria, with similarities in community assembly to marine stromatolites. Microbial diversity varied spatially and temporally within microbialites, and indicated that geographically proximal structures can develop with different communities. Significant changes also occur between summer and winter when the lake surface is frozen. Investigation of other nearby lakes with similar geochemistry but not supporting microbialites revealed extensive microbial mats. These developed in the presence of relatively high concentrations of methane or sulfate, and their biodiversity reflected this with several putative methanotrophic and sulphate utilizing taxa identified. No obvious cues that inhibit or promote microbialite formation were observed in this study. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy

This thesis addresses issues related to the development of Collaborative Virtual Environments (CVEs) for architectural design use. Today a new level of complexity has been brought to the meaning of virtuality by the creation of network-based virtual communities and the use of avatars along with multimedia which provides the technology for remote presence and collaborative experience. Communication and especially collaboration among design teams are now key factors in making the design process faster and more efficient in order to achieve increased competitiveness in the construction market. The objective of this thesis is to present a tool that is capable of creating 3D shapes in a shared VR environment, therefore allowing the evolution of the design to be a shared process. Along with its companion thesis (Conti, 2002) it gives the description of a framework and software prototype which could help practitioners using Virtual Reality technology by being a new interface for collaborative design at the early stages of the design process. The prototype system that is described here is called Java™ Collaborative Architectural Design tool in Virtual Reality JCAD-VR) and this thesis presents a description of its collaborative architecture. This thesis gives a description of the phases and technical solutions in the development of the network architecture and collaborative features of the JCAD-VR system. In addition, several different communication tools were used to enhance communication and the flow of information among the design teams and they are integrated in a Virtual Environment specifically created for architects. After the description of the software development the results are given of a test of the collaborative architecture of JCAD-VR and its ease of use in a real multi participant design experiment which show the potential and efficiency of using CVEs in architecture.

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The main part of the introduction illustrates the health care provision made in the past for workforces of the oil and gas industries functioning in remote places usually associated with an environmental hazard. Much of the past work has been carried out in the North Sea and the provision made there has been reviewed in some detail together with the gradual development of health care in the United Arab Emirates for both the offshore and the onshore oil-related workforces. There follows a short review of the provision made for two analogous situations - Newfoundland and Labrador and the British Antarctic Territories - since the developments there are of direct relevance to the Middle East situation. The main environmental hazard in the Middle East is heat and so the physiology and pathology of thermal balance in man are addressed in some detail. The first study is on the identification of the particular thermal problem which occurs in the offshore workings on the Abu Dhabi oil and gas companies, namely heat cramps. This problems had not been previously identified and the work done in determining its presence and its management is duly reported, indicating the problems of accepting health education material designed for one environment by another. In the development of systems of health care for both oil and non-oil related remote populations, the importance of training of the population at risk has been repeatedly emphasised. The perceived problems in that area are skill retention by laymen and the acceptance of the guidelines of the European and US Resuscitation Councils. A second study was therefore carried out to examine skill retention in laymen together with the feasibility of carrying out resuscitation manoeuvres in high temperatures.

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Thesis (Ph. D.)--University of Chicago, 1945. / Includes bibliographical references.

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The health care of those who work in remote places associated with hostile environments is reviewed, concentrating on the offshore oil industry and Antarctic populations. An understanding of associated environmental hazards is essential for adequate health care and particular attention is paid to the hyperbaric environment and to environmental heat and cold. The basic medical problems in remote health care are evaluated in three related studies. The first examines 2,162 personnel who required medical evacuations from the offshore structures of four North Sea operating companies, the second with 5,894 presentations from offshore at the A&E department of Aberdeen Royal Infirmary, while the third examines 100 annual medical reports from British Antarctic Survey stations.