1,819 research outputs found

    Lakshmi Planum: A distinctive highland volcanic province

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    Lakshmi Planum, a broad smooth plain located in western Ishtar Terra and containing two large oval depressions (Colette and Sacajawea), has been interpreted as a highland plain of volcanic origin. Lakshmi is situated 3 to 5 km above the mean planetary radius and is surrounded on all sides by bands of mountains interpreted to be of compressional tectonic origin. Four primary characteristics distinguish Lakshmi from other volcanic regions known on the planet, such as Beta Regio: (1) high altitude, (2) plateau-like nature, (3) the presence of very large, low volcanic constructs with distinctive central calderas, and (4) its compressional tectonic surroundings. Building on the previous work of Pronin, the objective is to establish the detailed nature of the volcanic deposits on Lakshmi, interpret eruption styles and conditions, sketch out an eruption history, and determine the relationship between volcanism and the tectonic environment of the region

    Bibliography of Sources on Dena’ina and Cook Inlet Anthropology Through 2016

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    This version 4.3 will be the final version for this bibliography, a project that was begun in 1993 by Greg Dixon. We have intentionally excluded all potential references for the year 2017. This version is about 29 pages longer and has about 211 entries added since the previous version 3.1 of 2012. Aaron Leggett has added over fifty sources many being rare items from newpapers and magazines. Also many corrections and additions were made to entries in earlier versions.I wish to thank Kenaitze Indian Tribe and the “Dena’ina Language Revitalization Project” for their support for several projects during 2017-2018, including this Vers. 4.3. Previous versions have had partial support from "Dena'ina Archiving, Training and Access" project (NSF-OPP 0326805, 2004) and from Lake Clark National Park. I thank Katherine Arndt of Alaska & Polar Regions at UAF for her careful proofreading

    Controlling Marangoni induced instabilities in spin-cast polymer films: how to prepare uniform films

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    In both research and industrial settings spin coating is extensively used to prepare highly uniform thin polymer films. However, under certain conditions, spin coating results in films with non-uniform surface morphologies. Although the spin coating process has been extensively studied, the origin of these morphologies is not fully understood and the formation of non-uniform spincast films remains a practical problem. Here we report on experiments demonstrating that the formation of surface instabilities during spin coating is dependent on temperature. Our results suggest that non-uniform spincast films form as a result of the Marangoni effect, which describes flow due to surface tension gradients. We find that both the wavelength and amplitude of the pattern increase with temperature. Finally, and most important from a practical viewpoint, the non-uniformities in the film thickness can be entirely avoided simply by lowering the spin coating temperature.Comment: 8 pages, 6 figures. electronic supplementary material: 3 pages, 4 figure

    Expression of a human cartilage procollagen gene (COL2A1) in mouse 3T3 cells.

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    Expression in a recombinant system has been difficult to obtain for any of the major fibrillar collagens that require processing by eight or more post-translational enzymes. Here, two DNA constructs were designed so that the promoter region of the gene for the pro-alpha 1(I) chain of human type I procollagen drove expression of the human type II procollagen gene in mouse NIH 3T3 cells, a culture line that normally synthesizes type I procollagen but not any cartilage-specific protein such as type II procollagen. Both constructs were expressed as both mRNA and protein. In clones expressing the construct at high levels, the steady-state levels of mRNA and the production of type II procollagen were comparable to the mRNA levels and production of type I procollagen from the endogenous mouse genes. Comparison of clones containing the two constructs demonstrated that sequences extending 80 base pairs beyond the major polyadenylation signal of the gene are not in themselves sufficient for correct termination and 3\u27 processing of RNA transcripts. The results strongly suggest that specific sequences present in a downstream 3.5-kilobase SphI/SphI fragment determine the termination of the transcription. Of special importance is that the system will make it possible to examine the consequences of mutations in the human type II procollagen gene on the processing of RNA transcripts and on the functional properties of the protein simply by using the genomic DNA from leukocytes or other non-cartilaginous sources

    Diversity in Morpheme Order in Several Alaskan Athabaskan Languages: Notes on the gh-qualifier

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    Proceedings of the Nineteenth Annual Meeting of the Berkeley Linguistics Society: Special Session on Syntactic Issues in Native American Languages (1993
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