1,721,082 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
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
Structure and evolution of the IGS region of the rDNA in Bacillus species (Insecta Phasmida).
No full textDoubly Uniparental Inheritance, an unusual pattern of mitochondrial DNA transmission in the bivalve mollusks Tapes philippinarum (Veneridae) and Musculista senhousia (Mytilidae).
No full textDoubly Uniparental Inheritance (DUI) represents an outstanding exception to matrilinear inheritance of mitochondria, typical of most Metazoa. Some bivalve mollusks posses two different mitochondrial DNA genomes (M and F mtDNAs) and realize a double mechanism of transmission in which M and F mtDNAs are passed by father to sons and by mother to daughters, respectively. Moreover, DUI has been also related to sex determination, since the presence of M mitocondria in the primordial germ line has been hypothesized to be the masculinization factor of the gonad. Mitochondrial DNA provides an intriguing system for addressing aspects of molecular evolution and intermolecular recombination in both DUI and non-DUI species and studies on DUI bivalves may have a pivotal role in understanding the evolution of the metazoan mitochondrial genome.
DUI has been found in a few mussel species (Mytilidae), as well as in several unionids (Unionidae). We started a wide analysis aimed to detect additional DUI systems and, actually, a venerid (Tapes philippinarum) and a mytilid (Musculista senhousia) species showed a mitochondrial heteroplasmy pattern, congruent with a DUI model of mtDNA inheritance.
Since T. philippinarum is the first venerid bivalve known to have DUI, our data showed that DUI also occurs in phylogenetically distant families and suggest that it might be widely distributed among bivalves. Furthermore, the T. philippinarum DUI system has been useful to test for selection on mtDNA genes under DUI, as well as for mitochondrial DNA recombination. To address these issues, a large sequence has been analyzed (i.e. a 9.2 kb region of the mitochondrial genome of T. philippinarum, containing 29 genes). Comparisons suggest that the two sex-related mitochondrial genomes do not experience a neutral pattern of divergence, and that selection may act with varying strength on different genes. This pattern of evolution may be related to the long, separate history of M and F genomes within their tissue-specific “arenas”. Moreover, our data suggest that recombinants, although occurring in the soma, may seldom be transmitted to progeny in this species.
The DUI system of M. senhousia revealed some unexpected traits, different from any previously known ones. Musculista heteroplasmy pattern is in line with standard DUI, but F haplotypes sequence variability is higher than that of M haplotypes. This is new for a DUI system, and it challenges most of the rationale proposed to account for sex-linked mtDNA evolution. Moreover, the system, tested for F mtDNA variability in somatic tissues, showed that F mitochondrial haplotypes experience a higher mutation rate in males than in females, thus suggesting that there might be some mechanism to keep a low mitochondrial DNA mutation rate in females. This fits well with evolutionary predictions: antioxidant gene complexes, evolved to protect mitochondria from oxidative damages, might be under relaxed selection in males. In phylogenetic trees M and F types clusters together, supporting that M. senhousia may have experienced ‘masculinization’ events in the lineage leading to the taxon. This also suggests that during the evolutionary history ‘masculinization’ might have been present in mytilids, other than Mytilus
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
Analisi paleogenetica dei cacciatori-raccoglitori della Sicilia: nuovi dati sul primo popolamento dell’isola
No full textThe first undisputed colonization of the island has been linked to Late or Final Epigravettian groups after the Last Glacial Maximum (LGM), as evidenced by the fossil record. Two significant sites to investigate this issue are the Grotta di San Teodoro (Acquedolci, Messina) and the Grotta d’Oriente (Favignana island). The Grotta di San Teodoro has yielded the oldest and largest human skeletal sample yet found in Sicily. Inside the cave, during field excavations carried out in the 1937-1947 years, seven human adults have been discovered (ST1-ST7). In the Grotta d’Oriente four prehistoric burials assigned to Late Upper Paleolithic (Oriente A and C) and Mesolithic (Oriente B and X) were unearthed during two campaign of ex-cavations (1972 and 2005). Thanks to the recent development of new methods for the analysis of ancient DNA (aDNA) coupled with Next Generation Sequencing technologies (NGS), it is nowadays possible to go deep inside the migration movements of human past populations. In order to better understand the peopling dynamics of Sicily during the Late Upper Paleolithic and Mesolithic, we analyzed and compared three complete mitochondrial genome sequences of ST2, Oriente C and Oriente B specimens. ST2 is an almost complete cranium attributed to a male, housed at the “G.G. Gemmellaro” Geo-logical Museum of the University of Palermo. The ST2 individual was buried near the ST1 skeleton, which was radiocarbon dated to 15,232-14,126 cal. BP. Oriente C individual was found during excavations of 2005. Two radiocarbon dates on char-coals are consistent with typical Late Epigravettian stone assemblages and refer Oriente C, a female only represented by the upper half of the skeleton, to a period spanning about 14,200-13,800 cal. BP. The Mesolithic Oriente B was unearthed in 1972. This individual, an almost complete skeleton attributed to an adult female, has been directly dated to 10,683-10,544 cal. BP. Paleogenetic analysis reveals a significant homogeneity in Sicilian Paleo-Mesolithic hunter-gatherers, and our data suggest a strong genetic relationship with Upper Paleolithic hunter-gatherers from Southern Italy, supporting the hypothesis that the first humans to arrive in Sicily could have originated from Epigravettian groups that migrated from the Italian pen-insula soon after the LGM
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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