1,720,968 research outputs found
Combinazione di approcci omici con analisi di equilibri di flusso per esplorare le dinamiche di popolazione in microbiomi anaerobici
Full text linkMicrobial methanogenic metabolism is one of the oldest bio-activities on Earth. This process is one of the main determinants of the fluxes in the global carbon cycle. In fact, in natural ecosystems, around one billion tons of methane is formed through microbial activity. Methanogenic process, mediated by complex microbial communities in anaerobic and microaerophilic environments, has raised great attention due to its energy generation potential. Constraint-based genome-scale metabolic modelling and metabolic flux balance analysis are pioneeristic tools for the investigation of large-scale relationships between genotype, phenotype and environment. Metabolic flux balance allows the integration of genomic data in the individual species-level metabolic models, feedstock information in the form of import flux bounds, and abundance data derived from metagenomic shotgun sequencing. The research reported in this PhD thesis focused on the establishment of a robust pipeline of flux balance analysis to unravel dynamics behind microbial communities involved in anaerobic digestion through two different cases of study: the investigation of a bioengineering process and the analysis of health-related microbial dynamics. The first case of study has been the analysis of the global microbial community behind the Anaerobic Digestion process in engineered systems. Anaerobic Digestion is the process leading to the generation of energy from biogas. Deciphering the anaerobic digestion “black box” is essential to optimise the biogas production and can allow the development of strategies to improve the process efficiency. The microbial community responsible for biogas generation is extremely complex and modifications of the environmental and operational parameters of the reactors deeply influence the abundance of the community members. This investigation helped decipher the correlation existing between species abundance and operational parameters of the biogas reactors. Understanding the required conditions for natural enhancement of desired endogenous consortia under anaerobic conditions paved the way to improve the yield of methane produced. The use of reactors enables a fine tuning of the anaerobic digestion, a dissection and a magnification of each step and component of the process. Therefore, the second case of study involved the application of the anaerobic digestion system as an ecosystem in a vessel for the analysis of metagenomic data from Crohn’s disease patients. In this model an additional complexity was considered: the integration of microbial and host metabolisms. Crohn’s disease is an inflammatory bowel disease affecting the digestive tract, it can lead to abdominal pain, severe diarrhea, weight loss and malnutrition. The inflammation often spreads deep into layers of affected bowel tissues and can be both painful and debilitating, and sometimes may lead to life-threatening complications. Although there is not widespread agreement on the aetiology of Crohn’s disease, microorganisms are recognized as the leading cause of the characteristic severe inflammatory response. The second case of study aimed to analyze metagenomic data of a Crohn’s disease patient with flux balance analysis to inspect the major modifications occurring in his gut microbiota during each stage of the disease development. The core of the project was the integration of longitudinal metagenomic data with flux balance analysis. In particular the development of the gut microbiome during acute and relapsing phases was studied to inspect the main microbe-microbe and microbe-host interplays responsible for the inflammation. The analysis shed light on the most altered metabolites during the disease onset.Microbial methanogenic metabolism is one of the oldest bio-activities on Earth. This process is one of the main determinants of the fluxes in the global carbon cycle. In fact, in natural ecosystems, around one billion tons of methane is formed through microbial activity. Methanogenic process, mediated by complex microbial communities in anaerobic and microaerophilic environments, has raised great attention due to its energy generation potential. Constraint-based genome-scale metabolic modelling and metabolic flux balance analysis are pioneeristic tools for the investigation of large-scale relationships between genotype, phenotype and environment. Metabolic flux balance allows the integration of genomic data in the individual species-level metabolic models, feedstock information in the form of import flux bounds, and abundance data derived from metagenomic shotgun sequencing. The research reported in this PhD thesis focused on the establishment of a robust pipeline of flux balance analysis to unravel dynamics behind microbial communities involved in anaerobic digestion through two different cases of study: the investigation of a bioengineering process and the analysis of health-related microbial dynamics. The first case of study has been the analysis of the global microbial community behind the Anaerobic Digestion process in engineered systems. Anaerobic Digestion is the process leading to the generation of energy from biogas. Deciphering the anaerobic digestion “black box” is essential to optimise the biogas production and can allow the development of strategies to improve the process efficiency. The microbial community responsible for biogas generation is extremely complex and modifications of the environmental and operational parameters of the reactors deeply influence the abundance of the community members. This investigation helped decipher the correlation existing between species abundance and operational parameters of the biogas reactors. Understanding the required conditions for natural enhancement of desired endogenous consortia under anaerobic conditions paved the way to improve the yield of methane produced. The use of reactors enables a fine tuning of the anaerobic digestion, a dissection and a magnification of each step and component of the process. Therefore, the second case of study involved the application of the anaerobic digestion system as an ecosystem in a vessel for the analysis of metagenomic data from Crohn’s disease patients. In this model an additional complexity was considered: the integration of microbial and host metabolisms. Crohn’s disease is an inflammatory bowel disease affecting the digestive tract, it can lead to abdominal pain, severe diarrhea, weight loss and malnutrition. The inflammation often spreads deep into layers of affected bowel tissues and can be both painful and debilitating, and sometimes may lead to life-threatening complications. Although there is not widespread agreement on the aetiology of Crohn’s disease, microorganisms are recognized as the leading cause of the characteristic severe inflammatory response. The second case of study aimed to analyze metagenomic data of a Crohn’s disease patient with flux balance analysis to inspect the major modifications occurring in his gut microbiota during each stage of the disease development. The core of the project was the integration of longitudinal metagenomic data with flux balance analysis. In particular the development of the gut microbiome during acute and relapsing phases was studied to inspect the main microbe-microbe and microbe-host interplays responsible for the inflammation. The analysis shed light on the most altered metabolites during the disease onset
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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