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Alimentation et Nutrition des juvéniles de Heterotis niloticus (Arapaimidae, Teleostei). Premières estimations des besoins nutritionnels et valorisation des sous-produits végétaux
No full textHeterotis niloticus is an African species with a great potential for fish farming as a result of its remarkably rapid growth, air-breathing characteristic, omnivorous diet, good meat quality and relative high commercial value. However, its use for aquaculture is limited due to the difficulty in the massive production of fingerlings and the lack of knowledge on its artificial feeding. Therefore, the estimations of its nutritional requirements at different ontogenetic stages are necessary in view of its effective contribution to the aquaculture production in Cameroon and other African countries. The present research aims to establish some basic nutritional variables relative to its fingerlings rearing and to examine the suitability of plant oil cakes as a partial substitute of fish meal in its compounded diets.
Between May 2005 and August 2008, several experiments were conducted in rectangular hapas (0.5 m3 useful capacity) placed in two earthen pond (300 and 600 m²) at the Melen Aquaculture Station (Yaounde, Cameroon). Replicate groups of juveniles were handfed twice daily to apparent satiation all the time. Analyses were performed at the laboratory of the Research Unit in Organismal Biology (University of Namur, Belgium) and the Unit of Industrial Chemistry Biology (Gembloux Agricultural University, Belgium).
On the protein and amino acids requirements, the results revealed that the dietary protein requirements are 310 and 345 g protein per kg diet for optimal and maximal growth, respectively for fish size ranging from 3 to 62 g. Based on whole body or muscle tissue indispensable amino acids to A/E ratios, its IAA requirement profile is similar to those of other omnivorous tropical fish species with the exception of tryptophan and histidine.
The dietary protein-sparing effect has been clearly demonstrated when the dietary energy of lipid increases from 17 to 19.6 kJ g-1 at 28% crude protein. Therefore, this result indicates that the optimum protein and lipid levels in its diet are 280 and 130 g kg-1 diet, respectively. Finally, the soybean and cottonseed oilcakes meals could partially replace up to 50% the dietary fish meal in its practical fingerlings diets without negative effect on maximal growth. This study contributes to improve our knowledge on basic nutrients requirements for the juveniles of a new aquaculture species for Africa.
However, massive production of quality fingerlings of this species remains a major obstacle to overcome on the road of the domestication of H. Niloticus for aquaculture use. Our work reveals that even with that constraint, optimism is permitted for a sustainable and rentable culture of this species in sub-Saharan Africa.L'Arapaimidae Heterotis niloticus est une espèce africaine à fort potentiel aquacole en raison de sa forte croissance, sa double respiration, la bonne qualité gustative et ferme de sa chair, et sa relative haute valeur commerciale. Toutefois, son utilisation à des fins piscicoles est limitée par la difficulté d'approvisionnement en alevins de qualité et par l'absence de connaissances sur ses besoins nutritionnels indispensables à l'optimisation de formules alimentaires pour l'espèce. En vue de sa contribution efficace dans l'augmentation de la production aquacole du Cameroun et des autres pays africains, la détermination entre autres de ses besoins alimentaires et nutritionnels à divers stades ontogénétiques s'avère nécessaire et incontournable. La présente recherche, inscrite dans cette perspective de domestication plus avancée de l'Heterotis du Nil, s'est proposée d'établir certaines variables nutritionnelles de base relatives à son pré-grossissement et d'évaluer ses capacités de valorisation des sous-produits oléagineux.
Entre mai 2005 et août 2008, une série d'expériences en triplicat sur la nutrition des juvéniles de H. niloticus ont été réalisées dans des hapas (0,5 m3 de volume en eau) installés en étangs de dérivation (300-600 m²) à la station aquacole de Melen (Yaoundé, Cameroun). Les analyses ont été effectuées au sein de l'Unité de Recherche en Biologie des Organismes des Facultés Universitaires Notre-Dame de la Paix (Namur, Belgique) et de l'Unité de Chimie Biologique Industrielle de la Faculté Universitaire des
Sciences Agronomiques (Gembloux, Belgique).
Sur le plan protéique, les résultats ont révélé que cette espèce nécessite 310 et 345 g protéines kg-1 d'aliment respectivement pour la croissance optimale et maximale des sujets pesant entre 3 et 62 g et que ses besoins spécifiques en acides aminés indispensables, excepté pour le tryptophane et l'histidine, sont similaires à ceux d'autres poissons tropicaux omnivores. Ensuite, le phénomène d'épargne des protéines par les lipides alimentaires a été clairement mis en évidence lorsque l'énergie a été augmentée de 17 à 19,6 MJ kg-1 d'aliment contenant 28% de protéines, ce qui nous a permis de suggérer que les besoins protéiques des juvéniles de H. niloticus peuvent être réduits de 310 à 280 g protéines kg-1 d'aliment dans les conditions expérimentales de notre étude. Enfin, la dernière approche de notre investigation a montré que les tourteaux de soja et de coton peuvent remplacer jusqu'à hauteur de 50% la farine de poisson dans l'alimentation des juvéniles de cette espèce. Ces différents acquis constituent en soi une avancée certaine dans la connaissance des besoins nutritionnels et alimentaires des Heterotis.
Le parcours de la domestication de cette espèce reste néanmoins encore difficile, notamment avec l'épineux problème de la production massive de juvéniles de qualité. Les perspectives de recherche-développement envisagées au terme de cette thèse laissent entrevoir de réelles chances de surmonter cet autre handicap-clé. Nous restons donc optimistes quant à l'élevage durable et rentable de ce poisson en Afrique sub-saharienne.(DOCSC03)--FUNDP, 200
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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