1,720,969 research outputs found
Microbial sensor variation across biogeochemical conditions in the terrestrial deep subsurface.
No full textImportanceThe ability to detect extracellular environmental conditions is a fundamental property of all life forms. Because microbial two-component sensor systems convert information about extracellular conditions into biochemical information that controls their behaviors, we evaluated how two-component sensor systems evolved within the deep Earth across multiple sites where abiotic and biotic properties vary. We show that these sensor systems remain abundant in microbial consortia at all subterranean sampling sites and observe correlations between sensor system abundances and abiotic (dissolved organic carbon variation) and biotic (consortia diversity) properties. These results suggest that multiple environmental properties may drive sensor protein evolution and highlight the need for further studies of metagenomic and geochemical data in parallel to understand the drivers of microbial sensor evolution
Microbial Ecology of Dry Permafrost from Elephant Head, Antarctica
No full textThe objective of this thesis is to determine if a viable, active microbial community could persist in cold, oligotrophic, dry permafrost soils from Elephant Head, Antarctica. Low amounts of microbial activity were measured in some microcosm samples at 5, 0, and -5C, as assessed using radiorespiration assays with radiolabeled acetate as a carbon source. Microbial communities were similar to other Antarctic environments and appear adapted for survival to cold, dry, oligotrophic conditions based on metagenomic, bacterial and fungal amplicon sequencing. The presence of viable microorganisms was confirmed through cultivation which isolated ~20 psychrotrophic organisms including Arthrobacter agilis strain Ant-EH-1 which is capable of cell division at -5C. The genome of A. agilis Ant-EH-1 was sequenced and was found to contain many genes for adaptation to cold, oligotrophic conditions. Together these results show that dry permafrost environments do not exclude active microbial life at sub-zero temperatures.Natural Sciences and Engineering Research Council of CanadaUniversity of GuelphPolar Knowledge CanadaNational Aeronautics and Space AdministrationCIFAR2024-04-1
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
Characterization of a Novel Chlorobenzoate Degrading bacterium: Burkholderia phytofirmans OLGA172, Isolated from a Pristine Environment
Full text linkBurkholderia phytofirmans OLGA172 is a chlorobenzoate (CBA) degrading bacterium, known to frequently lose the ability to degrade CBA in the lab. OLGA172 carries the complete set of genes for chlorocatechol degradation (an intermediate in CBA metabolism), tfdCDEF, as well as several integrases associated with DNA mobility in proximity to these genes. In this study, putative CBA degradative genes were identified in OLGA172, and an imbalance in regulation between the tfdCDEF and CBA degradative genes identified as a cause for incomplete CBA metabolism in this strain. Additionally, expression of the integrase genes was observed to occur constitutively. The role of this expression was not determined but hypothesized to be related to the phenotypic instability seen in OLGA172. Characterization of the strain was carried out with the aim to determine the ecological niche OLGA172 occupies naturally. Results of characterization are discussed in the context of evolution of the chlorocatechol degradative genes.MAS
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
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