1,721,097 research outputs found
Sub-lethal effects of dietary neonicotinoid insecticide exposure on honey bee queen fecundity and colony development
Full text linkMany factors can negatively affect honey bee (Apis mellifera L.) health including the pervasive use of systemic neonicotinoid insecticides. Through direct consumption of contaminated nectar and pollen from treated plants, neonicotinoids can affect foraging, learning, and memory in worker bees. Less well studied are the potential effects of neonicotinoids on queen bees, which may be exposed indirectly through trophallaxis, or food-sharing. To assess effects on queen productivity, small colonies of different sizes (1500, 3000, and 7000 bees) were fed imidacloprid (0, 10, 20, 50, and 100 ppb) in syrup for three weeks. We found adverse effects of imidacloprid on queens (egg-laying and locomotor activity), worker bees (foraging and hygienic activities), and colony development (brood production and pollen stores) in all treated colonies. Some effects were less evident as colony size increased, suggesting that larger colony populations may act as a buffer to pesticide exposure. This study is the first to show adverse effects of imidacloprid on queen bee fecundity and behavior and improves our understanding of how neonicotinoids may impair short-term colony functioning. These data indicate that risk-mitigation efforts should focus on reducing neonicotinoid exposure in the early spring when colonies are smallest and queens are most vulnerable to exposure.Wu-Smart, Judy; Spivak, Marla. (2016). Sub-lethal effects of dietary neonicotinoid insecticide exposure on honey bee queen fecundity and colony development. Retrieved from the University Digital Conservancy, 10.1038/srep32108
Why does bee health matter? The science surrounding honey bee health concerns and what we can do about it
Full text linkCAST Commentary; QTA2017-1 June 2017Spivak, Marla; Browning, Zac; Goblirsch, Mike; Lee, Katie; Otto, Clint; Smart, Matthew; Wu-Smart, Judy. (2017). Why does bee health matter? The science surrounding honey bee health concerns and what we can do about it. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/197606
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
Integrating science and policy: examining effects of neonicotinoid insecticides on honey bee (Apis mellifera L.) and bumble bee (Bombus impatiens Cresson) queens, worker bees, and colony development
No full textUniversity of Minnesota Ph.D. dissertation. September 2015. Major: Entomology. Advisor: Marla Spivak. 1 computer file (PDF); x, 229 pages.Exposure to neonicotinoid insecticides has been highly debated as a major contributor to the decline of bee health. In response to concerns over the potential effects of neonicotinoids on bees, the United States Environmental Protection Agency (US EPA) has made improvements to the regulatory risk assessments process for systemic insecticides. These improvements refine toxicity testing procedures to better establish appropriate uses (acceptable targets) and inform labeling (application rates and timing) to minimize non-target, or unintended, effects on bees. The main objective of these improvements is to increase field realism to obtain more accurate assessments on risks to bees in a natural setting. Each of the following chapters of this dissertation addresses a different aspect of the new risk assessment approach and provides data or suggestions to improve the procedure to better assess non-target effects of systemic neonicotinoid insecticides on bee pollinators. In the first chapter, experiments are described whereby honey bees (Apis mellifera L.) and bumble bees (Bombus impatiens Cresson) were fed imidacloprid syrup in acute toxicity tests at different concentrations, either at the standard quantity (10µl) or at a more field-realistic quantity (50µl) that resembled the amount of nectar foraging bees may hold in their crop to bring back to the hive, or nectar carrying capacity. Results indicated that bumble bees were more sensitive to imidacloprid than honey bees. Bumble bees were particularly more susceptible to becoming unresponsive after exposure rendering them nonfunctional and thus “ecologically dead.” In addition, the “lethal” concentration was considerably lower when measured endpoints included bees that were either physiologically dead or ecologically dead, suggesting higher toxicity to bees when toxicological consequences were considered in an ecological context. In chapter two, honey bee (A. mellifera) colonies consisting of various worker-population sizes (1500, 3000, and 7000 bees) were exposed chronically to imidacloprid syrup (0, 10, 20, 50, and 100ppb) for three weeks to assess the potential effects on queen bee fecundity and colony development. My results are the first to show dose-dependent effects of imidacloprid exposure on queen egg laying and locomotor activity, as well as on worker bee behavior, brood production, and pollen stores in all treated colonies. In addition, such negative effects lessened as colony size increased, suggesting that population size may act as a buffer to pesticide exposure through foraging efforts and increased nestmate interactions that might dilute exposure levels. In chapter three, I fed individual bumble bee (B. impatiens) queens imidacloprid chronically for 18-days. Imidacloprid was administered in syrup (1, 5, 10, 25 ppb) and pollen (0.3, 1.7, 3.3, 8.3ppb) in cage studies. Bumble bee queens exhibited reduced survival at all doses, even as low as 1 ppb. All treated queens that survived their initial exposure exhibited a significant dose-dependent delay in nest initiation or egg-laying, which led to the delayed emergence of worker brood. However, treated queens eventually commenced nest initiation after exposure, suggesting some recovery potential. The final chapter reviews the existing literature on effects of neonicotinoids on bees and organizes the findings using the Adverse Outcome Pathway approach to create a conceptual framework from which to better understand causal linkages among adverse effects across studies. In doing so I created a mechanistic explanation or pathway relating the mode of action of neonicotinoids to the specified adverse outcome: inhibition of colony development in honey bees and bumble bees by neonicotinoid exposure.Wu-Smart, Judy. (2015). Integrating science and policy: examining effects of neonicotinoid insecticides on honey bee (Apis mellifera L.) and bumble bee (Bombus impatiens Cresson) queens, worker bees, and colony development. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/183405
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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