1,721,014 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
Tuf-type characterization of Hungarian stolbur strains from different host species
No full textThe stolbur disease was described in Hungary more that fifty years ago on potato, pepper, tomato, tobacco and thorn apple (Datura stramonium). In the years of the ’50s, ’70s as well as in 2003-2005 stolbur disease caused mainly outbreaks in potatoes. The first molecular identification of stolbur phytoplasma was done by Viczian et al., (Növényvédelem, 34, 11. 1998) on the following species: pepper, tomato, parsley, rape, bladder campion (Silene vulgaris), and thorn apple. Later further plants and insect species joint to the list as carrot, celery, bindweed, nettle, common dandelion as well as grapevine, and Reptalus panzeri, indicating the wide spread presence of this phytoplasma in Hungary on crops and on wild plants as well. Molecular characterization of Hungarian stolbur strains has high importance to study epidemiology and to devise management of the disease in the field.
In this study the Tuf-type characterization of different Hungarian strains from grapevine, potato and tomato was performed. Stolbur positive samples identified on 16S ribosomal gene R16F2/R2 amplicons followed by TruI restriction digestion were amplified with fTuf1/rTuf1 and fTufAy/rTufAy primers in nested PCR, and digested with HpaII restriction enzyme (Langer and Maixner, Vitis, 43, 191-199. 2004) to identify the tuf-type. RFLP profiles obtained for the three species were referable to the stolbur tuf-type b. These results suggest possibility that stolbur phytoplasmas associated with major diseases of grapevine and potatoes are maintained in Convolvulus arvensis as wild host plant considering that this species is widespread in Hungary. This hypothesis is also supported by the high density of bindweed in all cultivated areas of Hungary. Further characterization of stolbur strains from the same species as well as from other species and insect vector or potential vector of stolbur phytoplasmas is in progress.
This study was (partly) supported by the ‘National Office for Research and Development’ as well as financed by the ‘Research and Technology Innovation Fund in Hungary’
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
Presence of Stolbur phytoplasma in Cixiidae from Hungarian grapevine growing areas
No full textBois Noir (16SrXII-A) phytoplasmas were identified in three grapevine-growing areas of Hungary in 18% of Hyalesthes obsoletus, and in an asymptomatic nettle sample. The cixiid Reptalus panzeri was found infected with 16SrXII-A and with 16SrIII (X-disease) group phytoplasmas. This latter pathogen was also detected in symptomatic wild Cirsium spp. and Convolvolus collected inside Bois Noir-infected and R. panzeri infested vineyards
Towards strain differentiation among grapevine bois noir phytoplasmas.
No full textSurveys carried out to identify bois noir phytoplasmas in grapevine yellows disease outbreaks in vineyards located in Hungary, Serbia, and Italy were performed during summer 2008. Selected samples were studied to check for polymorphism presence in 16S and spacer region, tuf and rpS3 genes. Using several restriction enzymes it was possible to identify different restriction profiles in some of the phytoplasma strains. Collective profiles of all bois noir strains studied were distinguishable from the three stolbur phytoplasmas used as reference strains and preliminary classified in the 16SrXII-A subgroup
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