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Master of Science
No full textthesisBacteriophages, a group of viruses that infect bacteria, are the most abundant biological entities on earth and play an outstanding role in microbial population dynamics in various ecosystems. Their potential as a driving force in the evolution of microbial communities through controlling the bacterial population, naturally selecting phage-resistant bacteria, and facilitating horizontal gene transfer has been studied mostly in an isolated environment like a laboratory setting. However, few studies have demonstrated the interaction between phages and the microbial communities in different natural ecosystems and hypersaline environments. The purpose of this research was to study the role of bacteriophages in functional gene transfer and how their hosts affect different nutrient cycles along with the interaction between bacteriophages and bacteria in a natural ecosystem using metagenomics approach with the knowledge of the state-of-the-art bioinformatics. The ecosystem studied in this research was the hypersaline Great Salt Lake, the largest salt water lake in the Western Hemisphere, for understanding the phage-host interactions. The sediment and water samples were collected from the deep brine layer of the Great Salt Lake, and analysis was conducted for different biogeochemistry. Also, the sediment sample was analyzed for both bacteria and viruses (bacteriophages) with metagenomics approach. Analyzing the viral and bacterial metagenomes explored the GC content, oligonucleotide frequency, genetic homology, Clustered Regularly Interspaced iv Short Palindromic Repeats (CRISPRs), and prophage identification. The in-depth metagenomics analysis identified phage and bacterial communities extensively and their effects on various nutrient cycles. This study also showed the variation in the prokaryotic community involved in various biogeochemical cycling due to the salinity gradient in the south arm caused by the railroad causeway constructed between 1955 to 1959, which divided the lake into two highly variable saline parts. The findings of microbial population, diversity, and their functional genes in this research using metagenomics approach will enhance the understanding of the bacterial and viral diversity in the Great Salt Lake and will be supportive in establishing metabolic models to better study the microbial interaction in various hypersaline ecosystems
Solid State Synthesis and Characterization of Apatite Based Ceramic Waste Form for the Immobilization of Radioactive Iodine
Get PDFThe growing demand for nuclear power in the United States and worldwide is accountable for addressing the major concern of radioactive waste, involving the technical challenges of maintaining the nuclear fuel cycle and immobilizing high-level wastes for safe disposal in geological storage. The appropriate selection of waste forms for spent nuclear fuel such as fission products and radionuclides can be effective means for a feasible and sustainable nuclear fuel cycle. But highly volatile radionuclides such as iodine (129) are of specific concern due to its extraordinary long half-life (15.7 million years). Due to its poor solubility and high volatility at traditional glass processing temperatures (~1000 oC), iodine is not suitable for processing using traditional vitrification routes. As a result, significant researches have been done to develop a viable waste form for immobilizing iodine. Among the most proposed waste forms, apatite-based ceramics have been proposed as promising candidates for immobilization of iodine due to its high-level nuclear waste loading, high chemical stability, structure flexibility, promising thermal and radiational stability, and low leaching rate. In this study, we introduce the first reported instance of solid-state synthesis of barium vanado iodoapatite (Ba5(VO4)3I) by a high-energy ball milling machine and spark plasma sintering (SPS) technique. Various characterization tools were used to characterize the synthesized materials. Understanding the mechanism of releasing radionuclides stored in nuclear waste forms in different environments is also crucial for the secure removal of nuclear waste. The effect of aqueous environment on iodine release of SPS sintered barium iodoapatite was investigated by conducting semi-dynamic leaching tests on bulk samples. The experimental analysis revealed that the iodine release rate from iodoapatite is affected by the solution chemistry. Irradiation experiments were conducted by using energetic ions and electrons to simulate radiation effects by α-decay and β-decay events, respectively in order to understand the radiation tolerance of this synthesized apatite structure and the underlying physics for the design of advanced nuclear waste forms. The results indicated that the SPS-sintered pellets can have significantly enhanced radiation tolerance of the iodoapatite against displacive radiation-induced amorphization due to the improved crystallinity by the highly efficient sintering process
Large P\'{o}lya groups in simplest cubic fields and consecutive bi-qaudratic fields
Get PDFThe P\'{o}lya group of an algebraic number field is the subgroup generated by
the ideal classes of the products of prime ideals of equal norm inside the
ideal class group. Inspired by a recent work on consecutive quadratic fields
with large class numbers by Cherubini et al., we extend the notion of {\it
consecutiveness} of number fields to certain parametric families of cyclic
cubic fields and bi-quadratic fields and address the question of the existence
of infinitely many such consecutive fields with large P\'{o}lya groups. This
extends a recent result of the second author and Saikia for totally real
bi-quadratic fields.Comment: 7 - epsilon pages. Comments are welcom
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
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