1,721,206 research outputs found
Chemical abundance analysis of CP Cyg and HD 33266
Get PDFWe selected two neglected A-type stars with low rotational velocity (v sin i < 20 km s −1) to reveal their chemical composition. Our abundance analysis was based on high resolution spectra of CP Cyg and HD 33266, obtained at the Tubitak National Observatory (TUG). We determined the fundamental parameters of our target stars from traditional methods. We also measured the abundances of 19 elements for CP Cyg and 20 for HD 33266 from the unblended lines emerging in the optical region of our spectra. The results of the analysis show that CP Cyg is a chemically normal A-type star, while HD 33266 is a metallic-line (Am) star. This is the first study in which HD 33266 is classified as a hot Am star. We also plotted the stars on the H-R diagram and calculated the masses from evolutionary tracks and ages from isochrones. We then compared both stars with members of similar ages and atmosphere parameters that belong to Coma Berenices and Hyades clusters. Our study is 6 Based on observations made at the Tubitak National Observatory, Turkey (Program IDs 09BRTT150-477-0). useful to understand the physical processes inside the atmospheres of chemically normal and peculiar A-type stars as well as their origin.peer-reviewe
Chemical abundance analysis of the A-type stars CP Cyg and HD 33266
No full textWe selected two neglected A-type stars with low rotational velocity (v sin i < 20 km s(-1)) to reveal their chemical composition. Our abundance analysis was based on high resolution spectra of CP Cyg and HD 33266, obtained at the Tubitak National Observatory. We determined the fundamental parameters of our target stars from traditional methods. We also measured the abundances of 19 elements for CP Cyg and 20 for HD 33266 from the unblended lines emerging in the optical region of our spectra. The results of the analysis show that CP Cyg is a chemically normal A-type star, while HD 33266 is a metallic-line star. This is the first study in which HD 33266 is classified as a hot Am star. We also plotted the stars on the H-R diagram and calculated the masses from evolutionary tracks and ages from isochrones. We then compared both stars with members of similar ages and atmosphere parameters that belong to Coma Berenices and Hyades clusters. Our study is useful to understand the physical processes inside the atmospheres of chemically normal and peculiar A-type stars as well as their origin. (C) 2014 Elsevier B.V. All rights reserved
HD 33266 ve 6 CAS’ın Kimyasal Bolluk Analizi
Get PDFBir Am yıldızı oldugu ilk kez belirlenen HD33266 ve süperdev bir yıldız olan 6 Cas'ın, yüksekçözünürlüklü tayfsal verileri TÜBİTAK Ulusal Gözlemevi'nde RTT150 teleskobuna baglı Coude Echelle Tayfçekeri kullanılarak elde edildi. Bu veriler yardımıyla yıldızlara ilişkin atmosfer parametreleri belirlendikten sonra kimyasal bolluk analizi gerçekleştirildi. HD 33266 için 25, 6 Cas için ise 13 ayrı atomik türe ilişkin bolluklar hesaplandı. 6 Cas'ın Hidrojen Balmer (H α , H β ve H γ)çizgi profilleri detaylı birşekilde incelenerek bu yıldızın yüksek hızlı yıldız rüzgarlarına sahip olabilecegi görüldü. Her iki yıldızın da H-R diyagramıüzerinde yerleri belirlenerek, evrim yollarından kütleleri, izokronlardan ise yaşları tayin edildi.peer-reviewe
Bifidobacterial lipoglycan as a new cause for false-positive platelia Aspergillus enzyme-linked immunosorbent assay reactivity.
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33266.pdf (Publisher’s version ) (Open Access)We previously hypothesized that a lipoglycan of Bifidobacterium bifidum subsp. pennsylvanicum cross-reacts with the Platelia Aspergillus (PA) enzyme-linked immunosorbent assay (ELISA) based on the presence of galactofuranosyl epitopes in the cell wall (M. A. S. H. Mennink-Kersten, R. R. Klont, A. Warris, H. J. M. Op den Camp, and P. E. Verweij, Lancet 363:325-327, 2004). We tested this hypothesis by testing bacterial suspensions of different bifidobacterial species and other gram-positive and -negative bacteria with the PA ELISA, which is used to detect circulating galactomannan for the serodiagnosis of invasive aspergillosis. Furthermore, neonatal fecal samples were enumerated for bifidobacteria by fluorescence in situ hybridization (FISH) and tested for PA ELISA reactivity. All bifidobacteria, except B. infantis and B. adolescentis, showed reactivity 6- to 600-fold higher compared to the controls (i.e., Micrococcus luteus and Propionibacterium freudenreichii, which contain a cell wall lipomannan). Eggerthella lenta showed a 25-fold-higher reactivity. ELISA reactivity was clearly shown to be associated with bacterial lipoglycans containing a beta-1,5-galactofuranosyl chain. All neonatal feces showed PA ELISA reactivity and associated numbers of bifidobacteria. Since high concentrations of bifidobacteria are present in the human gut, these bacteria or excreted lipoglycan may cause false serum PA ELISA reactivity in selected patient groups, especially neonates
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
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
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