1,720,956 research outputs found
Fungal strains and interactions with metals: studies in different contexts
No full textHeavy metal contamination in soils and water is an emerging problem. These elements, which are toxic even at low concentrations, can interact with living organisms, showing mutagenic and carcinogenic activities. This problem affects in particular the developing countries, where the population is in direct contact with highly contaminated water and food resources and thus exposed to real risks to their health. Among the many consequences of this phenomenon, the contamination of agricultural soils is a serious problem for environmental integrity and food safety. The accumulation of heavy metals in these soils affects soil fertility, reducing crop yields and ending up in food through the food chain. The sources of contamination are numerous and include both natural and anthropogenic activities. Many natural processes contribute to the deposition of trace metals, including rock erosion, forest fires and geological activities such as volcanic activity. However, the release of metals resulting from human activities, from the excessive use of chemical fertilisers and pesticides to the extraction and exploitation of resources and the production of waste, has increased significantly in recent decades.
Effective remediation strategies are needed to meet these problems. The remediation techniques developed in recent years are numerous and of various types, mainly based on the use of selective chemical-physical methods. However, they can be expensive, with a high energy consumption and a release of residual products. Emerging bioremediation methodologies are aimed at decontaminating and preserving the environment through the use of selected organisms. Promising techniques include mycoremediation, which uses fungal organisms in the treatment of contaminated substrates. Indeed, fungi are metabolically predisposed to rapid growth and can absorb and accumulate harmful substances without producing any waste. Their mycelial structure allows them to colonize large areas efficiently, making them a practical and accessible solution for soil decontamination.
The thesis is structured as follows: Chapter 1 introduces the issues related to environmental contamination by metals and the factors influencing their bioavailability; the interaction between fungi and metals; the differences between conventional decontamination methods and mycoremediation; the objectives of the thesis.
Chapter 2 presents the main materials and methods of different experiments.
Chapters 3 and 4 focus on the study of fungal interactions. Specifically, Chapter 3 examines the tolerance and bioaccumulation of arsenic from contaminated groundwater by native fungi compared to selected non-native fungi.
Chapter 4 provides an analysis of the potential mechanisms of tolerance and accumulation in fungi from soils with varying degrees of heavy metal contamination. The focus is on arsenic, cadmium, chromium and copper. An innovative method of washing the fungal biomass was also assayed.
Chapter 5 focuses on the characterization of the functional traits of fungi as potential plant growth-promoting fungi (PGPF). Subsequently, the application phase of mycoremediation was designed, simulating a paddy field environment within a greenhouse. The objective was to evaluate the effects of two distinct fungal inocula on three rice varieties under two different cultivation regimes in soil with high concentrations of heavy metals. Through this work, the study and the application of fungal strains in an important agricultural context such as rice cultivation were further explored. The findings highlighted the importance of selecting fungal strains based on metabolic and functional traits to enhance the effectiveness of bioremediation strategies, enabling not only the reduction of soil pollution but also improvements in plant health and harvest quality.
Chapter 6 is dedicated to the mycological characterization of three different paddy soils with varying levels of heavy metal contamination.
Chapter 7 focuses on a study of the fungal community in serpentinitic soils, which are naturally rich in potentially toxic elements (PTE) such as nickel, cobalt, and chromium. The results obtained through culture-based techniques were collected and compared with metabarcoding data.
Finally, Chapter 8 draws conclusions and discusses the significance of the results obtained, highlighting their implications for future developments
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
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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