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Étude des lignines des bois raméaux fragmentés des essences tropicales Gmelina arborea et Sarcocephalus latifolius et de leur devenir dans les sols agricoles au Bénin : effets sur l'aggradation des sols traités et l'amélioration de la production agricole
No full textL'application des bois raméaux fragmentés (BRF) dans les pratiques agricoles constitue une technique durable de restauration de la fertilité des sols. Et pourtant, la lignine qui lui confère majoritairement la capacité de formation de l'humus et de stabilisation du carbone organique du sol n'a pas encore fait objet d'une étude scientifique approfondie. L'objectif général de cette thèse de doctorat est de caractériser les lignines organosolv isolées des BRF de Gmelina arborea et Sarcocephalus latifolius et d'évaluer l'effet des amendements de ces BRF sur les propriétés physico-chimiques et la diversité fongique du sol ainsi que le rendement des cultures maraichères (tomate et gombo) sur deux sites agricoles au Bénin. Les objectifs spécifiques sont : (i) de déterminer les constituants et les propriétés chimiques du bois et des BRF des essences G. arborea et S. latifolius à partir des méthodes de chimie du bois; (ii) d'isoler et caractériser les lignines organosolv de ces essences par le procédé catalytique et suivre son devenir dans les sols sur deux sites au Bénin après deux ans ; (iii) d'évaluer les effets des amendements des sols avec les BRF sur le stock du carbone, la formation des substances humiques stables et la diversité fongique du sol; et (iv) d'évaluer les effets des amendements des sols avec les BRF sur les propriétés physico-chimiques et hydriques du sol ainsi que sur la production de la tomate et du gombo sur deux sites au Bénin. L'essence Gmelina arborea a été retenue pour le site de Sékou, et celle de Sarcocephalus latifolius pour celui de Kika. Les bois de tronc et BRF ont été caractérisés pour leur composition élément³¹aire et en lignines. La moitié des BRF était enfouie dans le sol, et l'autre moitié était utilisée comme paillis. L'effet des traitements a été évalué sur la production de la tomate et du gombo. Les BRF ont été échantillonnés après 0, 6, 12 et 18 mois d'incubation dans le sol afin d'isoler et caractériser leur lignine organosolv par des analyses spectroscopiques (FTIR, ³¹P RMN, 2D HSQC) et pyrolytique (Py-GC-MS-TMAH). Les résultats ont montré que les lignines organosolv des BRF des deux essences étaient de types guaiacyl-syringyl (G-S). Les analyses chimiques des BRF ont montré que la teneur en glucides totaux diminuait, tandis que la teneur en lignine totale augmentait au fur et à mesure de la décomposition des BRF dans le sol. Un enrichissement significatif en azote (N) des BRF a été déterminé après 18 mois d'incubation dans les sols, atteignant 2,6 et 1,9 fois la teneur initiale en N pour G. arborea et S. latifolius, respectivement. En outre, les BRF ont amélioré l'humidité volumique du sol, régulé la température du sol et diminué la tension hydrique du sol par rapport aux LV et témoins sur 24 mois. Par ailleurs, les traitements à base des BRF (BRF et BRF_LV) ont contribué de manière significative au stockage du carbone organique du sol et à l'augmentation des nutriments du sol (N, P, K, Ca, Mg) (cette dernière jusqu'à 1,5 fois) par rapport au témoin. Les résultats d'analyse de l'acide humique (HA) extrait des sols, purifié et analysé ont révélé que les sols amendés avec le BRF ont produit des quantités significatives d'HA constitués majoritairement des composés dérivés de lignine. En outre, en utilisant le séquençage de la région ITS2 sur la plateforme Illumina Miseq, l'application des BRF a considérablement modifié la composition fongique avec une augmentation de l'abondance relative des Ascomycota (jusqu'à 92% de la communauté fongique totale), Mucoromycota, Basidiomycota et Rozellomycota. Les résultats ont montré que l'amendement au BRF a réduit significativement le rendement de la tomate (sauf sur le site de Kika) et du gombo pendant la première production de culture et que l'amélioration de la croissance et du rendement de ces légumes a été significative qu'à partir de la deuxième production de culture. Cette recherche démontre ainsi le rôle positif des BRF à travers leur lignine à former de l'humus stable et à favoriser une production agricole durable.Application of RCW in agriculture is a sustainable technique for restoring soil fertility. However, the lignin from the RCW, which contributes to the formation of humus and to the soil organic carbon storage, has not yet been thoroughly studied. The general objective of this PhD thesis is to characterize the organosolv lignins isolated from RCWs of G. arborea and S. latifolius and to evaluate the effect of RCW amendments on the physico-chemical properties and fungal diversity of the soil as well as on the yield of vegetable crops (tomato and okra) on two agricultural sites in Benin. The specific objectives are: (i) to determine the constituents and chemical properties of trunk wood and RCW of G. arborea and S. latifolius using wood chemistry methods; (ii) to isolate and characterize the organosolv lignins of these species by the catalytic process and to follow its fate in soils on two sites in Benin after two years; (iii) to evaluate the effects of soil amendments with RCWs on carbon stock, formation of stable humic substances and soil fungal diversity; and (iv) to evaluate the effects of soil amendments with RCWs on soil physicochemical and hydric properties as well as on tomato and okra production on two sites in Benin. The G. arborea species was selected for the Sékou site, and S. latifolius for the Kika site. The trunk wood and RCW were characterized for their elemental and lignin composition. Half of the RCWs was incorporated in the soil, while the other half was put as mulch. The effect of the treatments was evaluated on tomato and okra production. RCWs were sampled after 0, 6, 12 and 18 months of incubation in the soil to isolate and characterize their organosolv lignins by spectroscopic (FTIR, 31P NMR, 2D HSQC) and chromatographic (Py-GC-MS-TMAH) analyses. The results showed that the organosolv lignins from RCWs of both species were of guaiacyl-syringyl (G-S) types. Chemical analyses of the RCWs showed that total carbohydrate content decreased, while total lignin content increased as RCWs decomposed in the soils. Significant nitrogen (N) enrichment of RCWs was determined after 18 months of incubation in soils, reaching 2.6 and 1.9 times the initial N content for G. arborea and S. latifolius. In addition, RCWs improved soil water content, regulated soil temperature, and decreased soil hydric tension compared to PL treated soils and controls over 24 months. Furthermore, RCW treatments (RCW and RCW_PL) contributed significantly to soil organic carbon storage and increased soil nutrients (N, P, K, Ca, Mg) (the latter up to 1.5 times) compared to the control. The humic acid (HA) was extracted from soils, purified, and analyzed by NMR spectroscopic and Py-GC-MS chromatography. The obtained results revealed that soils amended with RCWs produced significant amounts of HA containing a significant amount of lignin-related structures. Furthermore, using ITS2 region sequencing on the Illumina Miseq platform, RCW application significantly altered the fungal composition with an increase in the relative abundance of Ascomycota (up to 92% of the total fungal community), Mucoromycota, Basidiomycota and Rozellomycota. The obtained results showed that RCW amendment significantly reduced the yield of tomato (except at Kika site) and okra during the first crop production and that the improvement in growth and yield of these vegetables was significant only from the second crop production. This research thus demonstrates the positive role of RCWs through their lignin in forming stable humus and promoting sustainable agricultural production
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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