1,720,975 research outputs found
EFFECTS OF EXAVALENT CHROMIUM ON MAIZE, TOMATO, AND CAULIFLOWER PLANTS
No full textThe research presented in this paper was undertaken to study the short term response to hexavalent chromium [Cr(VI)] in seeds (caryopses), roots, and leaves of Zea mays, Lycopersicon esculentum, and Brassica oleracea, mainly in terms of ultrastructural alterations, Cr vacuole accumulation, and production of phytochelatins. Following a Cr(VI) treatment at concentrations of 5 and 10 mg l−1, the percentage of germination did not differ significantly between treated material and controls in all the species examined. However, Cr(VI) supply caused a decrease in the growth rate of the primary root and also a strong inhibition in the shoot growth. By means of transmission electron microscopy and X-ray microanalysis, we observed several "ultrastructural alterations of the treated material and the presence of electron-opaque precipitates, containing Cr, in the leaf tissue. In tomato plants treated with Cr(VI), no production of phytochelatins was detected either in roots or in leaves. Conversely, glutathione levels ranged from about 30 nmol SH g−1 FW of root extracts to 300 nmol SH g−1 FW of leaf extracts
MATERNAL AND PATERNAL LINEAGES IN ALBANIA AND THE GENETIC STRUCTURE OF INDO-EUROPEAN POPULATIONS
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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
Surnames in Albania: a study of the population of Albania through isonymy.
No full textIn order to describe the isonymic structure of Albania, the distribution of 3,068,447 surnames was studied in the 12 prefectures and their administrative subdivisions: the 36 districts and 321 communes. The number of different surnames found was 37,184. Effective surname number for the entire country was 1327, the average for prefectures was 653.3 ± 84.3, for districts 365.9 ± 42.0 and for communes 122.6 ± 8.7. These values display a variation of inbreeding between administrative levels in the Albanian population, which can be attributed to the previously published “Prefecture effect”.
Matrices of isonymic distances between units within administrative levels were tested for correlation with geographic distances. The correlations were highest for prefectures (r = 0.71 ± 0.06 for Euclidean distance) and lowest for communes (r = 0.37 ± 0.011 for Nei's distance).
The multivariate analyses (Principal component analysis and Multidimensional Scaling) of prefectures identify three main clusters, one toward the North, the second in Central Albania, and the third in the South. This pattern is consistent with important subclusters from districts and communes, which point out that the country may have been colonised by diffusion of groups in the North-South direction, and from Macedonia in the East, over a pre-existing Illiryan population
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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