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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
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The Impacts of Climate Change on Plant-Pollinator Phenological Synchrony Along Climatic Gradients in Dryland Ecosystems
Get PDFAnthropogenic climate change represents one of the most serious threats to ecosystems in the 21st century. As temperatures increase, and precipitation patterns are altered, species need to respond to living in increasingly arid environments. The most noticeable responses to changing climate is for populations to shift spatially, typically upward in elevation and latitude, and phenologically, typically by becoming phenologically active earlier in the year. Variation in how individual organisms or populations respond to climate change can alter their ecological interactions. The timing of flowering is species specific, and when and with whom a plant flowers adjacent to can impact their reproductive success. Between trophic levels, the synchronous phenology of flowering plants and pollinators is critical for both plant and pollinator reproductive success. Plant-plant and plant-pollinator phenological synchrony is at risk of deterioration due to aridification, potentially decreasing ecosystem functioning across the globe. While the bulk of previous research on this issue has been conducted in humid systems, plant- pollinator phenological synchrony has been in understudied in dryland ecosystems, which encompass over 40% of land globally. In the following chapters, I leverage natural history data along spatial and temporal gradients to determine the impacts of climatic variation on plant-plant and plant-pollinator phenological synchrony. I find evidence that plant-plant phenological synchrony is sensitive to changes in community composition. Plant-pollinator phenological synchrony decreases with increasing aridity at the community level, but some species are better suited to future aridification than others. My dissertation highlights the importance of understanding phenological synchrony in dryland ecosystems using analytical techniques specifically suited to the stochastic nature of climate change in these systems
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
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Tritrophic Mutualisms in a Changing Climate
Get PDFMutualistic species interactions are ubiquitous. Every species on Earth is involved, directly or indirectly, in a net beneficial partnership. Through shifts in partner phenology and distribution, climate change can disrupt mutualistic interactions, resulting in altered interactions and modified communities. However, research has focused on pairwise mutualisms, neglecting the fact that species interact with multiple mutualists simultaneously. In this dissertation, I explore the effects of climate change on nitrogen-fixing soil microbes, legume plants, and their pollinators. Climate change is predicted to affect the activity and ranges of belowground mutualists which will lead to changes in host plant germination timing and success, water use efficiency, floral traits, and, consequently, bee pollinator behavior. In the following chapters, I use a multi-year snowmelt timing manipulation, historical legume leaf tissue samples, and common garden techniques to assess the effects of belowground mutualism loss via climate stress on legume functional traits and legume-solitary bee interactions. I find evidence that climate warming, advanced snowmelt, and drought can lead to a short-term loss of interactions between soil microbes and leguminous plants, consequently leading to shifts in germination phenology, the quality floral rewards, plant nitrogen content, and consequently, pollinator floral preferences. Such costs could translate into reduced fitness and novel selection pressures for bees and flowering plants in the short term. My dissertation highlights the importance of studying multiple mutualisms in a climate change context and serves to identify the effects of soil microbial mutualism loss on legumes and on higher-order mutualists, such as bees
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
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Moth Pollination in a Changing Climate: Illuminating Risks and Conservation Strategies in Pollination’s Darkest Hour
Get PDFAnthropogenic global climate change can disrupt plant-pollinator interactions by altering the traits, phenologies, and distributions of interacting species, exacerbating insect declines and compromising ecosystem function. However, most research has focused on diurnal pollinators, and little is known about the prevalence, importance, and vulnerability of nocturnal moth pollination. This knowledge gap limits our ability to predict and mitigate the effects of climate change and other stressors on moths and their pollination services. In this dissertation, I investigate the ecology of moth pollination interactions, how moths and their host and nectar plants will be impacted by climate change, and how to apply this knowledge in conservation strategies. I focus on native plants and moths in California, a biodiversity hotspot that is particularly impacted by climate change. I employ techniques ranging from greenhouse experiments to DNA metabarcoding to explore impacts spanning the levels of functional traits to ecological networks. In Chapter 1, I document hundreds of previously undescribed moth pollen-transport interactions along an elevational gradient spanning desert to conifer forest. I also find that moths are smaller, less diverse, and more sensitive to the simulated loss of their nectar plants in hotter and drier conditions. In Chapter 2, I reveal that experimental warming and drought alter diel patterns of floral nectar quantity and quality in a generalist plant. This may differentially affect interactions with diurnal and nocturnal pollinators, scaling up to alter the structure and stability of plant-pollinator interaction networks. In Chapter 3, I analyze and compare Lepidoptera-host and -nectar plant interaction networks across California, revealing structural differences and spatial patterns that inform management priorities. I also analyze species roles in networks to identify spatially-explicit keystone plant species to be used in butterfly and moth conservation efforts. Together, my results reveal that moth pollination interactions are diverse, complex, and vulnerable to climate change, and that data-driven conservation strategies can help protect them. Ultimately, this dissertation highlights the importance of considering the nocturnal components of plant-pollinator networks in research and management
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