313 research outputs found
Astrobiology at Arizona State University: An Overview of Accomplishments
During our five years as an NAI charter member, Arizona State University sponsored a broadly-based program of research and training in Astrobiology to address the origin, evolution and distribution of life in the Solar System. With such a large, diverse and active team, it is not possible in a reasonable space, to cover all details of progress made over the entire five years. The following paragraphs provide an overview update of the specific research areas pursued by the Arizona State University (ASU) Astrobiology team at the end of Year 5 and at the end of the 4 month and subsequent no cost month extensions. for a more detailed review, the reader is referred to the individual annual reports (and Executive Summaries) submitted to the NAI at the end of each of our five years of membership. Appended in electronic form is our complete publication record for all five years, plus a tabulation of undergraduates, graduate students and post-docs supported by our program during this time. The overarching theme of ASU s Astrobiology program was "Exploring the Living Universe: Studies of the Origin, Evolution and Distribution of Life in the Solar System". The NAi-funded research effort was organized under three basic sub- themes: 1. Origins of the Basic Building Blocks of Life. 2. Early Biosphere Evolution. and 3. Exploring for Life in the Solar System. These sub-theme areas were in turn, subdivided into Co-lead research modules. In the paragraphs that follow, accomplishments for individual research modules are briefly outlined, and the key participants presented in tabular form. As noted, publications for each module are appended in hard copy and digital formats, under the name(s) of lead co-Is
A study of variation in the Bryozoan Fistulipora decora (Moore and Dudley) from the Beil Limestone Member of the Lecompton Limestone of Kansas
M.S. University of Kansas, Geology 1971An increasing number of bryozoan systematists are recognizing the need for a more quantitative treatment of variation in taxonomic studies of Bryozoa. The principal objective of this study was to isolate, as far as possible, the relative contributions of inter- and intracolony variation to the total variation of a population. Failure of the assumption of homogeneity of variances, for the data as a whole, precluded use of a nested analysis of variance model. This assumption was met by subsets of the data for several localities, and single classification anovas were applied in those instances.
Analysis of between locality differences by the Kruskal-Wallis anova analog revealed highly significant differences between localities. A nested anova (for which the assumptions had not been met) was performed for comparison, and resulted in nonsignificant values for between locality differences. This emphasized the hazard of using anova where assumptions are not met.
Analysis of within locality variance revealed highly significant differences between colonies. Significant intercolony variation within a locality can reasonably be attributed to a high degree of genetic diversity as the broad environment within the small area of the collecting site was seemingly relatively uniform. Partitioning of the total variance by single classification anova revealed that the greatest proportion of within locality variation is explained by differences within one colony. This is attributed to differences in the microenvironment affecting individuals within a single colony. Comparison of coefficients of intra- and intercolony variation, as suggested by Oliver (1968), was not appropriate in this study due to the significant overlap of 95% confidence limits for most cases. The independence of characters used in this study (as a measure of the degree of redundancy of information they provided) was evaluated by calculating a matrix of Pearson product-moment correlation coefficients. At least two independent characters could be recognized
Microbial Paleontology, Mineralogy and Geochemistry of Modern and Ancient Thermal Spring Deposits and Their Recognition on the Early Earth and Mars"
The vision of this project was to improve our understanding of the processes by which microbiological information is captured and preserved in rapidly mineralizing sedimentary environments. Specifically, the research focused on the ways in which microbial mats and biofilms influence the sedimentology, geochemistry and paleontology of modem hydrothermal spring deposits in Yellowstone national Park and their ancient analogs. Toward that goal, we sought to understand how the preservation of fossil biosignatures is affected by 1) taphonomy- the natural degradation processes that affect an organism from the time of its death, until its discovery as a fossil and 2) diagenesis- longer-term, post-depositional processes, including cementation and matrix recrystallization, which collectively affect the mineral matrix that contains fossil biosignature information. Early objectives of this project included the development of observational frameworks (facies models) and methods (highly-integrated, interdisciplinary approaches) that could be used to explore for hydrothermal deposits in ancient terranes on Earth, and eventually on Mars
Who Are The Social "Entrepreneurs" and What Do They Actually Do?
There is increasing interest in the social entrepreneur and the process of social entrepreneurship. This has led to criticisms of fuzziness surrounding these concepts. This paper explores the concept of the social entrepreneur, considering whether social entrepreneurs can really be termed "entrepreneurs" or if they are something else - individuals motivated by meeting social objectives to achieve social change. Drawing on structuration theory, we place the agent (a social entrepreneur) in the structure (a social system/the context), arguing that they are engaged in a process of co-constructing the current momentum in social entrepreneurship development
Exobiology site priorities for Mars Pathfinder
The fact that life developed on the Earth within the first billion years of its history makes it quite plausible that life may have also developed on Mars. If life did develop on Mars, it undoubtedly left behind a fossil record. Such a fossil record is likely to be more accessible than either subsurface environments that may harbor life, or scattered 'oases' that may be present at the surface. Consequently, the post-Viking approach of Mars exobiology has shifted focus to search for evidence of an ancient martian biosphere. This has led to the emergence of a new subdiscipline of paleontology, herein termed 'exopaleontology', which deals with the exploration for fossils on other planets and whose core concepts derive from Earth-based Precambrian paleontology, microbial ecology, and sedimentology. Potential targets on Mars for subaqueous spring deposits, sedimentary cements, and evaporites are ancient terminal lake basins where hydrological systems could have endured for some time under arid conditions. Potential targets for the Mars Pathfinder mission include channeled impact craters and areas of deranged drainage associated with outflows in northwest Arabia and Xanthe Terra, where water may have ponded temporarily to form lakes. The major uncertainty of such targets is their comparatively younger age and the potentially short duration of hydrological activity compared to older paleolake basins found in the southern hemisphere. However, it has been suggested that cycles of catastrophic flooding associated with Tharsis volcanism may have sustained a large body of water, Oceanus Borealis, in the northern plains area until quite late in martian history. Although problematic, the shoreline areas of the proposed northern ocean provide potential targets for a Mars Pathfinder mission aimed at exploring for carbonates or other potentially fossiliferous marine deposits. Carbonates and evaporites possess characteristic spectra signatures in the near-infrared and should be detectable using rover-based spectroscopy and other methods for in situ mineralogical analysis
Exopaleontology and the search for a fossil record on Mars
Although present Martian surface conditions appear unfavorable for life as we know it, there is compelling geological evidence that the climate of early Mars was much more Earth-like, with a denser atmosphere and abundant surface water. The fact that life developed on the Earth within the first billion years of its history makes it quite plausible that life may have also developed on Mars. If life did develop on Mars, it is likely to have left behind a fossil record. This has led to the development of a new subdiscipline of paleontology, herein termed 'exopaleontology', which deals with the exploration for fossils on other planets. The most important factor enhancing microbial fossilization is the rapid entombment of microorganisms by fine-grained, stable mineral phases, such as silica, phosphate, or carbonate. The oldest body fossils on Earth are preserved in this way, occurring as permineralized cells in fine-grained siliceous sediments (cherts) associated with ancient volcanic terranes in Australia and South Africa. Modern terrestrial environments where minerals may precipitate in the presence of microorganisms include subaerial thermal springs and shallow hydrothermal systems, sub-lacustrine springs and evaporitic alkaline lakes, zones of mineralization within soils where 'hardpans' (e.g. calcretes, silcretes) form, and high latitude frozen soils or ground ice
Fluvial processes in Ma'adim Vallis and the potential of Gusev crater as a high priority site
According to exobiology site selection criteria for Mars, the search for potential extinct/extant water dependent life should focus on sites were water flowed and ponded. The Ma'adim Vallis/Gusev crater system is of high priority for exobiology research, because it appears to have involved long term flooding, different periods and rates of sedimentation, and probable episodic ponding. The topics covered include the following: evidence of nonuniform fluvial processes and early overflooding of the plateau and ponding
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