1,720,956 research outputs found
Ecological succession of the microbial community of a spacecraft assembly facility in enriched brines relevant to Mars
No full textHonorable mention in the poster presentations at the 16th Annual Symposium on Graduate Research and Scholarly Projects (GRASP) held online, Wichita State University, May 1, 2020.Research completed in the Department of Biological Sciences, Fairmount College of Liberal Arts and SciencesLife detection missions to Mars should be as free of microbial organisms as possible to avoid transporting contaminants on spacecraft surfaces. Any microbes that make the trip to Mars or the round-trip back to Earth may compromise our ability to recognize authentic biosignatures from native Mars organisms. Current planetary protection protocols require that any spacecraft components must be assembled in cleanrooms that have nearly aseptic conditions, reducing the chance of microbial contamination. This current research studies samples from NASA's Jet Propulsion Laboratory Spacecraft Assembly Facility (JPL-SAF), collected from high-traffic surfaces and entryways. Microbes from these samples were enriched in brines representative of Mars' high-salt environment. Through the use of leading-edge molecular genetic techniques, detailed descriptions of the changing microbial communities were made at regular timepoints for up to six months. Over forty bacteria present in the brines after six months of enrichment were isolated, characterized, and identified to determine which microbial strains from JPL-SAF wipes are most likely to survive under the conditions of near-surface Mars. Knowing if microbes from SAFs could potentially survive on Mars informs efforts to protect Mars from microbial contamination that can complicate life detection or harm potential native ecosystems.Graduate School, Academic Affairs, University Librarie
Ecological succession of the microbial community of a spacecraft assembly facility in enriched brines relevant to mars
Full text linkThesis (M.S.)-- Wichita State University, College of Liberal Arts and Sciences, Dept. of Biological SciencesLife detection missions to Mars should be as free of microbial organisms as possible to
avoid transporting contaminants on spacecraft surfaces. Any microbes that make the trip to Mars
or the round-trip back to Earth may compromise our ability to recognize authentic biosignatures
from native Mars organisms. Current planetary protection protocols require that spacecraft
components must be assembled in cleanrooms that have nearly aseptic conditions, reducing the
chance of microbial contamination. The current research studies samples from NASA’s Jet
Propulsion Laboratory Spacecraft Assembly Facility, collected from high-traffic floor surfaces
and entryways. Microorganisms from these samples were enriched in liquid media based on 50%
MgSO4 and 20% NaClO3 brines representative of Mars’ high-salt environment. Through the use
of leading-edge molecular genetic techniques, 16S and 18S rRNA sequences provided detailed
descriptions of the changing bacterial and fungal communities at timepoints over a six-month
period. Bacterial communities were dominated by staphylococci increasing in diversity over
time. Fungal communities were dominated by Saccharomycetes decreasing in diversity over six
months. Thirty-eight bacterial isolates were collected after six months in the enrichment brines,
identified through Sanger sequencing of 16S rRNA, characterized through morphology and
biochemical assays, and grown in a variety of salts to measure tolerances. The culture collection
contains halotolerant, Gram-positive bacteria found in Staphylococcus, Brevibacterium,
Brachybacterium, and Oceanobacillus genera that can survive in a variety of high-salt brines.
Those that persisted in the enrichment brines for an extended period may pose the greatest risk to
life detection missions as they might be the most likely to survive and proliferate at the nearsurface
of Mars. This research informs efforts to protect Mars from microbial contamination that
can confound life detection or harm potential native ecosystems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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