1,720,954 research outputs found
Modelling two decades of change and future developments in the Gulf of Nicoya (Costa Rica) ecosystem using the Ecopath with Ecosim toolbox
No full textThe Gulf of Nicoya is a highly productive estuary located on the Pacific coast of Costa Rica and accounts for the country’s primary fish production. It is increasingly impacted by its fisheries and climate variations, urbanization, tourism developments, the input of pollutants from urban centres, and agriculture activities in the catchment areas of large rivers entering the gulf. Thus, our study intensively assesses the Gulf of Nicoya’s past, present, and future states and the main driver of ecosystem change. The state of the ecosystem, food-web dynamics, detectable patterns in fishing efforts, and the external drivers’ influence on the system were analyzed. Also, the economic impacts of fishing effort regulations were simulated to test and propose possible management plans. A spatial model was also built to test the effect of a temporary fishing closure on the stock recovery of target species in the Gulf of Nicoya and to propose management alternatives.
In the early 1990s, ecological and fishery data from the Gulf of Nicoya were holistically analyzed, and a trophic model was constructed using the Ecopath modelling approach. The results indicated that this tropical estuary, a hotspot for Costa Rican fisheries, was already overexploited by shrimp trawlers and longline fleets, and recent observations suggest further deterioration in this system. To evaluate the ecosystem and socio-economic changes in the Gulf of Nicoya over the last 20 years, the 1993 model was reconstructed with data from 2013 to compare both system states. Although the summary statistics of both states (i.e., 1993 and 2013) suggest that the system maintained its general functionality and even enabled the total harvest to increase by approximately 20%, a more detailed analysis of the levels of the functional groups led to the conclusion that the system was further degraded, causing a tremendous economic loss of approximately 50%. Like other coastal ecosystems, the Gulf of Nicoya is impacted by its fisheries, anthropogenic activities, and pollution from the large rivers entering the gulf. Thus, the gulf is particularly sensitive to short- and long-term changes in the climate, especially during extreme conditions in El Niño periods. For further analysis, we used a holistic approach to examine the impacts of fishing and environmental changes to identify the main drivers in the observed changes in the Gulf of Nicoya ecosystem. While the model simulations indicate that fisheries’ exploitation rates mainly drive variations in the catchment, several species are also substantially affected by climate variations. This factor must be considered alongside implementing fishing regulations to form and develop appropriate management strategies. This dissertation tested the effectiveness of different management scenarios applied to the Gulf of Nicoya, including top-down and participatory fishing policies. Besides testing the current policy (which bans shrimp trawling), we used the automated fishing policy search tool of the EwE software to explore an alternative, optimized management scenario. The analysis indicates that the ban on trawling is important for the ecosystem’s recovery. However, additional measures might be needed, such as reducing fishing efforts by semi-industrial purse seine fleets and artisanal longline fleets. We present two possible alternative management scenarios with different balances of ecosystem conservation and economic losses. We complement our extensive analysis by adding a spatial component using the Ecospace tool, which can simulate species’ spatial distribution and fishing fleet effort over time. One obvious application is the assessment of the efficiency of existing and potential locations of MPAs to explore spatial management options and address various research questions, including the regional consequences of climate change. The approach was used to test the effectiveness of the existing annual seasonal fishing closure in the gulf (known as “Veda” in Spanish) and to tackle further questions. For example, is excluding all fleets from the gulf necessary during fishing closure? Would a seasonal closure covering the entire area of the Gulf of Nicoya be more efficient?
This intensive assessment of the state of the Gulf of Nicoya ecosystem leads to the conclusion that a drastic decrease in fishing effort, especially of semi-industrial fleets, is needed to maintain the ecosystem’s functionality, rebuild the biomass of target species, and strengthen its resilience to environmental change. In this process, the enforcement of the fishing closure will play an important role
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
- …
