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Populationsmanagement von Feldmäusen - Geburtenkontrolle und Beköderungsstrategien
Get PDFCommon voles (Microtus arvalis) are one of the most common vertebrate pest species in Europe. The management of overabundant rodent pest species is crucial as they cause severe agricultural losses and pose risks to human health and livestock in outbreak years. The use of anticoagulant rodenticides is one of the most common management approaches and alternatives are urgently needed. There is increasing interest in fertility control but no product is registered for rodent management in the European Union. Ideal fertility control products are species-specific, easy to administer, have minimal side effects, are cost-effective and environmentally benign.
In a series of studies, the potential and concept of fertility control for rodents was assessed and the effects of 4-Vinylcyclohexene diepoxide (VCD) and Triptolide (TP) on the reproductive organs and sperm quality of male common voles were investigated. In addition, a bait containing the quantitative marker Ethyl-Iophenoxic acid (Et-IPA) for common voles was developed, a dose-response relationship was established. In an enclosure trial, the effectiveness of two common baiting strategies and whether they were effective enough to deliver anti-fertility compounds to a sufficient fraction of the population to achieve population-level effects was tested.
For field application, there are promising results based on synthetic steroids (levonorgestrel, quinestrol), chemosterilants (4-Vinylcyclohexene diepoxide), and plant extracts (triptolide). All of them have been efficient in females and/or males in laboratory studies and can be orally delivered. However, all of these potential fertility control agents need more research before use in European agricultural systems, that focusses on their efficient and cost-effective delivery, to achieve impacts at population level and ultimately to minimize crop loss.
The administration of bait containing VCD and TP to male common voles for 14 or 28 consecutive days showed minor effects on reproductive organs. While there was no significant impact on testes weight, sperm viability, or oxidative stress in sperm cells, there was an increase in morphological sperm defects observed. Importantly, there were no or minimal residues of VCD and TP in liver tissue, suggesting low risk of secondary exposure to non-target species.
Et-IPA is a suitable bait marker for common voles. It can be easily incorporated into a bait, has no side effects, does not affect palatability and is stable enough in vole blood to allow flexibility in sampling. Both baiting strategies (tunnel baiting and bait boxes) appear appropriate for reaching a significant portion of the population, but there are inconsistent extrinsic and intrinsic influences on bait consumption. The baiting strategies did not have a major impact on the percentage of animals consuming bait but higher Et-IPA blood residues were present if tunnel baiting was used in autumn and if bait boxes were used in winter.
The low effects of VCD and TP on male reproductive organs and sperm quality raise doubts about the effectiveness for the management of common voles with these compounds at the concentrations used. Further research should investigate the effects of VCD and TP on the reproductive organs of female voles and on reproductive success in mating trials. Both baiting strategies are sufficient for fertility control but need to be validated in field trials
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
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