1,721,010 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
[[alternative]]Detection of hybridization in the genus Takydromus in eastern Taiwan
No full text[[abstract]]Takydromus formosanus Boulenger 1894 includes two unpublished, cryptic species: T. viridipunctatus, distributed in northern Taiwan including Taipei, Keelung, and Yilan, with its southern boundary around the northern bank of the Liwu River; and T. luyeanus, distributed in Hualian and Taidong, with its northern boundary around the southern bank of Liwu River. The close phylogenic relationship and geographic distributions of T. viridipunctatus and T. luyeanus may provide important informations to study speciation and hybridization of higher organisms. In this study, we aim to detect the existence and degree of probable hybridization occurring in the potential contact zone between these parapatricly distributed species by using microsatellite and mitochondrial DNA markers.
According to our data, sympatric distribution between T. viridipunctatus and T. luyeanus is not found in this study. However, among the 299 samples collected from the potential contact zone, about 3%~10.4% individuals were detected to be hybrids within 13-loci and 6-loci analyses. The microsatellite and/or mitochondrial DNA information of the purported hybrids show different patterns to adjacent individuals and carry genetic characters of the other species. Low proportions of hybrids carry mitochondrial DNA information of another species. It is presumed that the large proportions of equivocal individuals could be hybrids due to male introgression, and the introgression of T. viridipunctatus and T. luyeanus is bidirectional. Low dispersal rate and certain selection forces may play important roles in constraining hybridization.
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
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
[[alternative]]Phylogeny and Phylogeographic Studies of Takydromus in Taiwan and Adjacent Regions (Squamata: Lacertidae)
No full text[[abstract]]Abstract
The East Asian grass lizard genus, Takydromus Daudin in the family Lacertidae, is distributed in the Oriental and Palearctic regions. With specialized slender body shape and extraordinarily long tails, most Takydromus species inhabit in grasslands, dense scrub, or forest edge. At the beginning of my study in 1998, there were 16 or 17 species recognized in this genus, belonging to two subgenera: Takydromus and Platyplacopus. One of the most spectacular features of grass lizards in biogeography is the high percentage of endemism in the islands. Almost half of Takydromus species are endemic to the islands aligned along the Pacific coast of the East Asian continent. The formation and evolution of Takydromus in this region is an interesting issue in biogeography research (Chapter 1).
In Chapter 2, I sequenced the complete mitochondrial 12S rRNA from 14 Takydromus OTUs. Phylogenetic relationship was constructed by MP, NJ and ML methods, and the results of these three criterions are congruent. Three major groups were identified within this genus, whereas the monophyly of both subgenera was not supported. According to our deduction, the speciation process of Takydromus is closely related to the pattern of land connection among island groups influenced by glaciations. The vicariance between neighboring islands triggered the divergence between species. Furthermore, a model of multiple colonizations was proposed to explain the prominent difference of interspecific distance among different Takydromus groups. A rough estimation on the evolutionary rate helps us to deduce the age of each historical event, while this estimation would also be applied in the following sections.
Although the model of inter-island vicariance explained the distribution of most Takydromus species, an “ in situ speciation ” model was further proposed to explain the biodiversity of grass lizard in Taiwan. In Chapter 3, I collected T. formosanus from 27 locations throughout the entire island. Mitochondrial sequencing represented significant differentiation among eastern, western, and northern populations in Taiwan. With diagnostic morphological characters, two of these “evolutionarily significant units”, the northern lineage and the eastern lineage, were suggested to evaluate as new species. The combination of T. formosanus, T. hsuehshanensis, and T. wolteri formed a monophyletic group, and was defined as “Takydromus formosanus species complex”. The evolutionary relationship among the five members within this species complex was discussed in Chapter 3.
In Chapter 4, I focused on the population genetic study of Takydromus stejnegeri, another island-endemic species in Taiwan. Fourteen populations were collected, sequenced, and analyzed with nested clade analysis (NCA). Two to three major lineages were detected in T. stejnegeri, with partially overlapping distribution in northern Taiwan. Their current distribution was deduced to be a post-glacial expansion from two or three refugial regions. The recent history of “range expansion” for T. stejnegeri was supported by the evidence from NCA, neutrality tests, and frequency spectrum.
The periodical occurrence of glaciations caused the demographic fluctuation of these lizards. To figure out the pattern of such influences, I applied the analysis of NCA to the four endemic units of T. formosanus species complex in Chapter 5. The genetic pattern of the northern species (Takydromus sp. N) and the eastern species (Takydromus sp. E) were similar to that in T. stejnegeri, revealing a deep intraspecific branching with partially overlapping distribution. The demographic fluctuation in these two species was prominent, but not present in T. formosanus distributed in western Taiwan. An interspecific competition with T. stejnegeri is a probable explanation for its comparatively stable demographic history. On the other hand, the expected population decline in T. hsuehshanensis was not observed, probably owing to the analytical power of NCA or the adequate sampling for this species.
With seven species including six endemics, the island of Taiwan represents the highest biodiversity of Takydromus in the world. However, our knowledge on these secretive lizards is still limited. In Chapter 6, I will make some prospect on concerning studies in the future, and make a conclusive comment on the study of Takydromus in the past five years.
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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