1,720,953 research outputs found
Impact of storms and floods on Mediterranean coastal marine ecosystems. Approach by coupled hydrodynamic-biogeochemical modeling.
No full textLes milieux côtiers, dont les lagunes côtières, sont à l’interface entre le continent et la zone hauturière. Ils font partie des zones les plus riches en terme de productivité biologique. Cette position d’interface engendre une variabilité importante des variables physico-chimiques (p. ex. la température, la concentration en nutriments) et biologiques, influençant le fonctionnement de ces écosystèmes. De plus, dans un contexte de changement climatique global, cette variabilité pourrait être accentuée, en particulier par des événements extrêmes tels que les événements de tempêtes et de crues. Il est donc indispensable de développer des études scientifiques pluridisciplinaires sur ces milieux marins côtiers afin de mieux appréhender les variabilités naturelles de ce système d’une part, et d’autre part quantifier la tendance et l’amplitude des modifications liées aux changements environnementaux à moyen et long terme.Dans cette thèse, l’impact des événements de tempêtes et de crues sur les écosystèmes marins côtiers en Méditerranée a été étudié sur une zone littorale particulière : la lagune de Thau (Sète, France) et son avant-côte. L’impact d’une potentielle modification de ces événements hydro-météorologiques intenses sur ces mêmes écosystèmes a aussi été étudié, en lien avec le changement climatique. Pour répondre à cette problématique principale, nous avons proposé une approche par modélisation 3D couplée hydrodynamique-biogéochimie (SYMPHONIE - ECO3M-S) décrivant l’évolution des variables physico-chimiques sur le littoral (courants, pression, niveau d’eau, température, salinité, etc.) et biogéochimiques (biomasse des micro-organismes marins, matière particulaire et dissoute, sédiment).Le modèle ECO3M-S a d’abord été adapté à la lagune de Thau, lieu privilégié pour les activités ostréicoles, en intégrant le forçage par les huîtres sur les compartiments trophiques inférieurs (zooplancton, phytoplancton et bactéries), mettant en évidence un impact négatif sur le phytoplancton (filtration) et favorisant les bactéries. Ensuite, une première expérience de modélisation 3D a été effectuée sur l’épisode cévenol de novembre 2008, validant la démarche suivie et donnant une première analyse de l’impact court terme de ce type d’événements sur l’écosystème étudié. Malgré les apports fluviaux importants dans la lagune de Thau, la biomasse du phytoplancton n’augmente pas durant cet événement, en raison d’une possible limitation par la lumière et par la température de l’eau. Ceci met en avant des effets contradictoires de ces événements sur les écosystèmes. Une période plus longue (2015 - 2016) a été envisagée ensuite, comprenant plusieurs événements intenses, afin d’évaluer un impact à moyen et long terme. Cette modélisation a été validée à l’aide d’observations in situ et des tests statistiques ont été réalisés. Enfin, l’impact de différents scénarii de modification des événements extrêmes sur le bilan biogéochimique de la lagune de Thau et de son avant-côte a été quantifié. A court terme, Les bilans biogéochimiques et la biomasse des micro-organismes est nettement modifiée par les événements. A long terme, le système montre une certaine résilience aux modifications des forçages environnementaux, même si des écarts persistent une année après les événements extrêmes. Ceci est relié à une inertie différente des processus biogéochimiques s’établissant au sein de la colonne d’eau et du compartiment sédimentaire.Ce travail de thèse apporte une meilleure compréhension de l’impact à court, moyen et long terme des événements de tempêtes et de crues sur les écosystèmes marins côtiers, donnant de premières pistes concernant l’impact d’une potentielle modification future de ces événements sur l’évolution biogéochimique du littoral méditerranéen.Coastal environments, including coastal lagoons, at the interface between land and sea, often display a rich biological productivity. This unique position creates significant variability of the physical, chemical (e.g., temperature, nutrient concentration) and biological variables, thus influencing how these ecosystems function. In the context of global climate change, widely accepted by the scientific community, this variability could be amplified particularly by extreme intense events such as storm and flood events. It is therefore essential to develop multidisciplinary scientific studies on these coastal marine environments in order to better understand the natural variabilities of this system. Additionally, it is needed to quantify the trend and magnitude of the variability associated with medium and long-term environmental changes.In this thesis, the impact of storm and flood episodes on Mediterranean coastal marine ecosystems was studied on a particular coastal zone: the Thau lagoon (Sète, France) and its nearshore. In addition, the impact of a potential modification of these intense hydro-meteorological events, in relation with climate change, on these same ecosystems was also studied. To answer the main objective, a 3D coupled hydrodynamic-biogeochemistry modeling approach (SYMPHONY - ECO3M-S) was used, describing the evolution of physical and chemical variables (currents, pressure, water level, temperature, salinity, etc.), and biogeochemical variables (biomass of marine micro-organisms, particulate and dissolved matter, sediment).The ECO3M-S model was first adapted to the Thau lagoon, a privileged location for oyster farming activities, by integrating the forcing by oyster on the lower trophic compartments (zooplankton, phytoplankton and bacteria), showing a negative impact on phytoplankton (filtration) and promoting bacteria. Then, a first 3D modeling experiment was performed on the “cevenol” episode of November 2008, validating the approach followed and giving a first analysis of the short-term impact of this type of event on the studied ecosystem. Despite significant river inputs into Thau Lagoon, phytoplankton biomass did not increase during this event, due to possible light and water temperature limitations. The results highlights contradictory effects of these events on the ecosystem functioning. A longer period (2015 - 2016) was then considered, including several intense events, to assess a medium- and long-term impact. The modelling results was validated using in situ observations and statistical tests were performed. Finally, the impact of different scenarios of a modification of extreme events on the biogeochemical balance of the Thau Lagoon and its nearshore was quantified. In the short term, the biogeochemical balances and biomass of micro-organisms were significantly affected by intense events. In the long term, the system showed a good resilience to the modification of environmental forcings, even if differences persist one year after extreme events. This was linked to different inertia of the biogeochemical processes within the water column and the sedimentary compartment.This thesis provides a better understanding of the short, medium and long-term impact of storm and flood events on Mediterranean coastal marine ecosystems. In addition, this thesis shows the possible impact of a potential future modification of intense events on the biogeochemical evolution of the North-Western Mediterranean
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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