1,721,020 research outputs found
Functional traits underlying the invasion success of IAS (Invasive Alien Species)
Get PDFThe issue of alien species, especially invasive aliens (IAS), is the current focus of the international scientific debate owing to the negative effects that such species have caused and continue to cause to ecosystems, economic activities and human health. In Italy, there was an increase of 96% of alien species (over 3,000) over the last thirty years. The reason for the widespread diffusion of alien species lies in some features that make them particularly competitive, such as the resistance to pests, the ability to adapt to different environmental conditions, including anthropized habitats, and the competitive superiority in gaining resources compared to native species.
Climate change and biological invasions are two important drivers affecting biodiversity and ecosystem services. However, their effect on biodiversity has usually been assessed independently, despite good scientific reasons to expect the rate and extent of biological invasions to be influenced by climate change. Resident species can become increasingly poorly adapted to the local environment, whereas newcomers might be better adapted and, thus, more competitive under the new conditions. Populations of alien plants are considered more likely to survive if they are introduced to areas with climatic conditions similar to those in their native distribution range.
Changes in climatic conditions resulting in a prolonged growing and reproductive period often provide alien species with exploitable opportunities. Indeed, there is increasing evidence that global warming can enable expasion into areas where the species were previously kept in check by climate. Over recent decades, an increasing number of studies have analysed patterns of biological invasions to disentangle the underlying ecophysiological processes. Under this perspective, the recent focus on the functional traits or the syndrome of traits enhancing the invasive potential of IAS, holds promise to develop predictions on which species are more likely to become successful invaders in different habitats. Functional trait ecology represents a relatively novel approach to investigate this phenomenon. Functional traits provide tools for measuring functional diversity, as they impact plant fitness via effects on growth, reproduction and survival, and reflect the trade-offs among different physiological and ecological functions. In particular, through the ecophysiological processes it is possible to understand how the different processes of growth, reproduction and distribution of IAS are influenced by the interaction with ecological factors (abiotic and biotic).
Many factors may contribute to the invasion success, including seed production and germination, high relative growth rate (RGR), seedling recruitment, carbon allocation, life history characteristics of species, and susceptibility to disease and/or herbivores.
The aim of the present thesis was to identify the functional traits that underline the invasion process of three widespread IAS in Italy: Ailanthus altissima (Mill.) Swingle, Robinia pseudoacacia L. and Phytolacca americana L.. In particular, the focus has been directed to three fundamental aspects, i.e., seed germination traits, seedlings growth dynamics and physiological and morphological traits of seedlings under drought condition. The focus was to understand which traits allow a better performance to IAS and if there are common strategies of considered species.
The results presented through the three Chapters of the thesis provide a significant contribution to characterize ecophysiological behaviour of three important IAS to expand knowledge on functional traits underline the invasion process of IAS. In particular, the results from:
- Chapter 2 demonstrate that a global temperature increase could be considerably increase germination percentages of some species and future warmer conditions could naturally break seed dormancy, extending the favourable period for seedling establishment;
- Chapter 3 provide compelling evidence that certain traits, such as rapid growth, high leaf production rate and high leaf area production rate are considered intrinsic characteristics that can give species some advantages for the colonization of new sites and therefore increase their distribution; in addition, it highlights not all invasive species respond in the same way at temperature and seedling growth reflects the climatic conditions of the native habitat. The considered traits can be useful to help disentangle the trait dimensions by which IAS cope with air temperature change;
- Chapter 4 explore how water stress affect the functional traits related to gas exchange in each considered species. The results shows a species dependent effect of the water stress at a physiological and morphological level as well as an interaction between species and stress duration. In particular, the study reveal the considered IAS differ mainly in their capacity to control photosynthesis through stomatal control, highlighting a different species responsiveness in coping with water stress.
Overall, the present PhD Thesis by analysing the response to temperature and water availability variations at different plant life stages (i.e., germination and seedling) contribute to the scientific debate on the IAS capacity to face the current climatic changes. In particular, the results reveal that the extent of the response to environmental factor variations, differs among IAS due to different capacity to maximize their performance under limiting environmental conditions. Accordingly, the results highlight the importance of integrating physiological functional information to better understand the invasion strategies of these IAS in the perspective of planning more effective measures of their management and control
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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