1,721,012 research outputs found
Variations in marine microbiomes: from habitat to host
Full text linkSubmitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 2022.Microorganisms are the dominant life form on Earth and inextricably tied to the ecology and evolution of all multicellular life, including marine animals. As the importance of microorganisms to our conception of life gains prominence, animals (and other macroorganisms) are increasingly viewed as “holobionts”, an assemblage of the host plus all its symbiotic microbes. This dissertation examines holobiont biology from the perspective of the microbial communities that live in and around marine
hosts. Using both amplicon and metagenomic sequencing, I study the microbiomes of reef-associated seawater and Atlantic killifish to better understand habitat and host effects on microbiome structure. In two Caribbean reef systems, I used examined the
biogeography of reef water microbes. I found that the microbiome of reef seawater varies with reef system and individual reefs but that microbiomes within individual reefs were similar to each other and did not vary with benthic composition. The regionalism of reef seawater microbiomes was further assessed upon incorporation of global scale data from five additional studies, which revealed that microbial communities were more distinct with increasing geographic distance. These results contribute to our understanding of the coral holobiont’s microbial environment and can inform monitoring efforts for reef health. Atlantic killifish populations can be categorized as sensitive or tolerant to industrial pollutants based on history of pollutant exposure. Thus, they are an excellent “natural laboratory” for understanding the combined effect of environment and host on microbiome composition. I examined the gut microbiomes of two populations of wild fish as well as captive fish originating from each of these wild populations. I found that living in and adapting to polluted waters can impact microbiome composition and structure, resulting in a microbiome that appears more disordered. Additionally, captivity resulted in a complete turnover of dominant microbial taxa, indicating the environment plays a large role in shaping killifish gut microbiomes. This dissertation demonstrates that diverse systems, from coral reefs to killifish, can benefit from a better understanding of its associated microorganisms. For holobiont studies, these results highlight the importance of considering the context of microbial communities, from environment to host population.My time in the MIT-WHOI Joint Program was supported by the Civil and Environmental Engineering department at MIT, the Schoettler scholarship fund, the National Science Foundation, and the Academic Programs Office at WHOI. The research presented here was supported by Rockefeller Philanthropy Advisors, the Dalio Foundation, and NSF awards OCE-1938147 and NSF OCE-1928761 to Amy Apprill; Joint Initiative Funds from the W. Andrew Mellon Foundation to Amy Apprill and Mark Hahn; and Ocean Venture Fund to Lei Ma
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
Flow cytometry and nutrient analyses data from a tidal study over 48 hours of mangrove, seagrass, and seawater from the US Virgin Islands in July of 2017
No full textDataset: Tidal study of seawater microbial communitiesData from a tidal study over 48 hours of mangrove, seagrass, and seawater from the US Virgin Islands in 2017. These data include tidal height, depth, temperature, salinity, Prochlorococcus counts, Synechococcus counts, Picoeukaryote abundances, nutrient concentrations at accession numbers for sequences at The National Center for Biotechnology Information (NCBI) Sequence Read Archive (SRA).
For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/783679NSF Division of Ocean Sciences (NSF OCE) OCE-173628
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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