1,720,967 research outputs found
Evolutionary relationships of the sooglossid frogs of Seychelles
No full textThe granitic islands of the Seychelles are Gondwanan fragments, and have remained isolated for in the region of 63 million years. Their origin dates to a period contemporaneous with the Cretaceous-Paleogene boundary extinction event, and volcanic activity that formed the Deccan Traps. The archipelago is a biodiversity hotspot, and much of its biota is endemic. Among Seychelles fauna, the sooglossid frogs are globally significant. The only amphibian family entirely restricted to an archipelago, until recently they were found on just two islands in the Seychelles. Sooglossids are amongst the top 100 EDGE amphibians, and currently classified by the IUCN as either Endangered (Sooglossus sechellensis, Sechellophryne gardineri) or Critically Endangered (So. thomasseti, Se. pipilodryas). In 2009 a population of sooglossid frogs was discovered on a third island, Praslin, and subsequently revealed to be a unique lineage. Morphometric and bioacoustic data from the Mahé, Silhouette, and Praslin sechellensis frogs (the sechellensis group), and DNA sampling from each island population of the Sooglossidae, was collected for an assessment of the sechellensis group. Principal component and discriminant function analyses of morphometric data identified separate populations of sechellensis group frogs; Silhouette frogs were the largest with shorter hind limbs; Praslin frogs were the smallest but possessed longer hind limbs; Mahé frogs were also distinct but shared greater similarities with Silhouette frogs. Vocalisations of the Praslin Sooglossus differed from other sechellensis group frogs in structure, pulse rate, primary note length, and call duration. Mitochondrial phylogenies identified strongly supported, island-specific lineages of sechellensis group frogs in independent analyses, a pattern that was repeated for So. thomasseti. Haplotype networks for nuclear loci were less resolved than mtDNA phylogenies but showed geographic patterns. Combined mitochondrial and nuclear DNA species delimitation analyses showed strongly supported intraspecific discrimination within So. sechellensis, and So. thomasseti. An anuran phylogeny found a sister-group relationship between the Sooglossidae and Ranoidea, in accordance with previous work. Finally, divergence dating estimated the origin of the Sooglossidae in the Late Jurassic, the divergence of Sooglossus-Sechellophryne in the Late Cretaceous, followed by a sequence of key splits between genera (Sooglossus, Sechellophryne) and island-specific lineages (So. thomasseti, So. sechellensis) during the Late Paleogene, which correspond with a major decrease in global sea levels. However, both the anuran phylogeny and divergence dating analyses will benefit from additional loci and further, more stringent tests of the data and initial outputs. The analyses provide the basis for recognition of the Praslin Sooglossus and Silhouette sechellensis as novel taxa (confirmed candidate species), and pending further work, the Silhouette populations of So. thomasseti and Se. gardineri (unconfirmed candidate species). Urgent recognition of taxonomic status is required to facilitate targeted conservation to safeguard this distinct and unique anuran family. The demise of even one population would be a significant loss to global biodiversity and evolutionary history
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
Evolutionary Genetics and Conservation of the Critically Endangered Arabian Leopard (Panthera pardus nimr)
Get PDFLarge carnivores are considered an important component of an ecosystem and their role as apex predators makes them crucial for maintenance of ecosystem function and biodiversity. Yet despite their important ecological value, large carnivores are among the world's most threatened species, mostly due to human persecution and loss of their habitat and prey species. The Arabian leopard (Panthera pardus nimr) is the region's last remaining big cat, and was once widely distributed across the Arabian Peninsula but its occupied range has contracted from ~888,300 km2 to 17,400 km2 since the 1970s, and it is listed as Critically Endangered on the IUCN Red List of Threatened Species. Despite its threatened status, scientific information is lacking for many aspects of the Arabian leopard, including its population and evolutionary genetics. The objectives of this study were therefore to improve the knowledge base to help develop better management strategies for the long-term persistence of the Arabian leopard. By generating a comprehensive mitochondrial DNA sequence database that included sequence data from wild Arabian leopard populations across the Arabian Peninsula my study provided evidence that the Arabian leopard is evolutionarily distinct from other leopard subspecies. Assessment of genetic diversity using a suite of microsatellite markers indicate that the Arabian leopard is genetically impoverished in comparison to other leopard subspecies. However, high levels of genetic diversity and unique alleles were discovered in wild and captive Arabian leopards of Yemeni origin, compared to the wild leopards of the Dhofar mountains of Oman, an area considered to be their last stronghold. Using genetic data from wild leopards obtained via non-invasive scat surveys, we detected fine-scale spatial genetic structure within the leopard population of Dhofar which is likely due to recent human development in the region. DNA surveys of the Dhofar population provided robust estimates of density and population size that are comparable with those derived from camera trap estimates, indicating the reliability of genetic sampling for monitoring of the Arabian leopard. Based on these findings a number of conservation management strategies are proposed including genetic rescue via introgression of Yemen genes to restore the genetic diversity of impoverished populations and enhance the overall evolutionary potential of the Arabian leopard. Other suggested measures include strengthening legislation and enforcement in combination with community engagement to ease human-wildlife conflict as well as the protection and safeguarding of critical habitat and habitat corridors to address population fragmentation. Urgent adoption of these recommendations is required, and the novel information generated by this research provides the evidential basis for their effective implementation that will help ensure the long-term persistence of the Arabian leopard
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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