1,720,956 research outputs found
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
Evaluation of restoration success for semi-natural and flower meadows in the Oslo municipality
Full text linkWhile cities are often overlooked as targets for conservation, ecologists have argued that the urban environment is actually a good candidate for re-creating semi-natural meadows, since these nutrient-poor grasslands prefer dry, well-drained soils and are adapted to human disturbance. Although semi-natural meadows are potentially vulnerable to eutrophication and domination by non-target plant species, they are also capable of becoming very species-rich. A number of these meadows have therefore been created or restored in Oslo, Norway in recent years, and this study evaluates the success of these projects.
We surveyed vascular plants (excluding Poaceae) at 11 sites, including 3 calcareous meadows, 3 hay meadows, and 5 generic flower meadows. Despite a severe drought in the growing season of 2018, the majority of our sites appeared to be relatively resilient. On the other hand, the extreme impact to one rooftop meadow showed the importance of adaptive management even for meadows that are expected to be self-sufficient after establishment. We found that, in line with other studies, undisturbed soil was less likely to recruit non-native plants. Commercial soil was not worse than soil from local donor meadows in this regard, but local soil was potentially better able to recruit target species through the preserved seed bank. Non-native plants were additionally associated with high pH and phosphate. Phosphate in particular was high in some sites, possibly due to soil geology, which indicates that pre-restoration soil testing may be necessary.
We found that re-created meadows were generally much more alkaline than reference meadows, suggesting that the project organizer over-estimated the target pH for these sites. We also found that the reference sites were less biodiverse than new sites, possibly due to the exclusion of mosses and lichens from the data, insufficient sampling, or because new sites will lose species over time. Plant family abundances showed clear divisions based on the project organizer responsible for the site, demonstrating the importance of this top-down effect, but were still differentiated based on meadow type. Importantly, we found that the techniques used in this study were straightforward and useful, with some suggestions for improvement
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
Methods for tagging an ectoparasite, the salmon louse Lepeophtheirus salmonis
Full text linkMonitoring individuals within populations is a cornerstone in evolutionary ecology, yet individual tracking of invertebrates and particularly parasitic organisms remains rare. To address this gap, we describe here a method for attaching radio frequency identification (RFID) tags to individual adult females of a marine ectoparasite, the salmon louse Lepeophtheirus salmonis. Comparing two alternative types of glue, we found that one of them (2-octyl cyanoacrylate, 2oc) gave a significantly higher tag retention rate than the other (ethyl 2-cyanoacrylate, e2c). This glue comparison test also resulted in a higher loss rate of adult ectoparasites from the population where tagging was done using 2oc, but this included males not tagged and thus could also suggest a mere tank effect. Corroborating this, a more extensive analysis using data collected over two years showed no significant difference in mortality after repeated exposure to the 2oc glue, nor did it show any significant effect of the tagging procedure on the reproduction of female salmon lice. The proportion of RFID-tagged individuals followed a negative exponential decline, with tag retention among the living female population generally high. The projected retention was found to be about 88% after 30 days or 80% after 60 days, although one of the four batches of glue used, purchased from a different supplier, appeared to give significantly lower tag retention and with greater initial loss (74% and 60% respectively). Overall, we find that RFID tagging is a simple and effective technology that enables documenting individual life histories for invertebrates of a suitable size, including marine and parasitic species, and that it can be used over long periods of study.publishedVersio
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
Data: Methods for tagging an ectoparasite, the salmon louse Lepeophtheirus salmonis
No full text<p>Monitoring individuals within populations is a cornerstone in evolutionary ecology, yet<span> </span>individual tracking of invertebrates and particularly parasitic organisms remains rare. To address this gap, we describe here a method for attaching radio frequency identification<span> </span>(RFID) tags to individual adult females of a marine ectoparasite, the salmon louse<span> </span><em><span>Lepeophtheirus salmonis</span></em>. Comparing two alternative types of glue, we found that one of them<span> </span>(2-octyl cyanoacrylate, <em><span>2oc</span></em>) gave a significantly higher tag retention rate than the other (ethyl<span> </span>2-cyanoacrylate, <em><span>e2c</span></em>). This glue comparison test also resulted in a higher loss rate of adult ectoparasites from the population where tagging was done using <em><span>2oc</span></em>, but this included males<span> </span>not tagged and thus could also suggest a mere tank effect. Corroborating this, a more extensive analysis using data collected over two years showed no significant difference in<span> </span>mortality after repeated exposure to the <em><span>2oc </span></em>glue, nor did it show any significant effect of the<span> </span>tagging procedure on the reproduction of female salmon lice. The proportion of RFID-tagged<span> </span>individuals followed a negative exponential decline, with tag retention among the living<span> </span>female population generally high. The projected retention was found to be about 88% after<span> </span>30 days or 80% after 60 days, although one of the four batches of glue used, purchased from<span> </span>a different supplier, appeared to give significantly lower tag retention and with greater initial<span> </span>loss (74% and 60% respectively). Overall, we find that RFID tagging is a simple and effective technology that enables documenting individual life histories for invertebrates of a suitable size, including marine and parasitic species, and that it can be used over long periods of study.</p>
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
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