1,355,770 research outputs found
Mitochondrial DNA signals of late glacial recolonization of Europe from near Eastern refugia
No full textHuman populations, along with those of many other species, are thought to have contracted into a number of refuge areas at the height of the last Ice Age. European populations are believed to be, to a large extent, the descendants of the inhabitants of these refugia, and some extant mtDNA lineages can be traced to refugia in Franco-Cantabria (haplogroups H1, H3, V, and U5b1), the Italian Peninsula (U5b3), and the East European Plain (U4 and U5a). Parts of the Near East, such as the Levant, were also continuously inhabited throughout the Last Glacial Maximum, but unlike western and eastern Europe, no archaeological or genetic evidence for Late Glacial expansions into Europe from the Near East has hitherto been discovered. Here we report, on the basis of an enlarged whole-genome mitochondrial database, that a substantial, perhaps predominant, signal from mitochondrial haplogroups J and T, previously thought to have spread primarily from the Near East into Europe with the Neolithic population, may in fact reflect dispersals during the Late Glacial period, ?19–12 thousand years (ka) ago.<br/
The Genetic Ancestry of Modern Indus Valley Populations from Northwest India
No full textThe Indus Valley has been the backdrop for several historic and prehistoric population movements between South Asia and West Eurasia. However, the genetic structure of present-day populations from Northwest India is poorly characterized. Here we report new genome-wide genotype data for 45 modern individuals from four Northwest Indian populations, including the Ror, whose long-term occupation of the region can be traced back to the early Vedic scriptures. Our results suggest that although the genetic architecture of most Northwest Indian populations fits well on the broader North-South Indian genetic cline, culturally distinct groups such as the Ror stand out by being genetically more akin to populations living west of India; such populations include prehistorical and early historical ancient individuals from the Swat Valley near the Indus Valley. We argue that this affinity is more likely a result of genetic continuity since the Bronze Age migrations from the Steppe Belt than a result of recent admixture. The observed patterns of genetic relationships both with modern and ancient West Eurasians suggest that the Ror can be used as a proxy for a population descended from the Ancestral North Indian (ANI) population. Collectively, our results show that the Indus Valley populations are characterized by considerable genetic heterogeneity that has persisted over thousands of years.sponsorship: We thank the Ror, Gujjar, Kamboj, and Jat communities for their support of this study and all individual volunteers for donating their samples. R.V. thanks the Swedish Collegium for Advanced Studies for support during his sabbatical stay in Uppsala. We thank Lehti Saag, Bayazit Yunusbayev, Hovhannes Sahakyan, Jose Rodrigo Flores Espinoza, and Erwan Pennarun for useful discussions and assistance. We thank Tuuli Reisberg for her assistance in genotype data curation. We also thank Mari Jarve for language editing. All data analyses were performed at the High-Performance Computer Centre of the University of Tartu, Estonia (http://www.hpc.ut.ee).Support was provided by the European Union through the European Regional Development Fund Centre of Excellence for Genomics and Translational Medicine (project no. 2014-2020.4.01.15-0012) to the EBC-IG and by the Estonian Institutional Research grant IUT24-1 (to A.K.P., R.V., M. Metspalu, S.R., E.M., and T.K.). M. Metspalu was supported by Estonian Research Council grant PRG 243. M. Mondal was supported by the European Union through the European Regional Development Fund (project no. 2014-2020.4.01.16-0030). G.C. is supported by National Geographic Explorer grant HJ3-182R-18, A.K. was supported by Estonian Personal grant PUT 1339, and L.P. was supported by the European Union through the European Regional Development Fund (project no. 2014-2020.4.01.16-0024, MOBTT53). A.K.P. was supported by the European Social Fund's Doctoral Studies and Internationalization Programme DoRa. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. (European Union through the European Regional Development Fund Centre of Excellence for Genomics and Translational Medicine|2014-2020.4.01.15-0012, Estonian Research Council|PRG 243, European Union through the European Regional Development Fund|2014-2020.4.01.16-0030, European Union through the European Regional Development Fund|2014-2020.4.01.16-0024, European Union through the European Regional Development Fund|MOBTT53, National Geographic Explorer grant|HJ3-182R-18, Estonian Personal grant|PUT 1339, Estonian Institutional Research grant|IUT24-1, European Social Fund's Doctoral Studies and Internationalization Programme DoRa)status: Publishe
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
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