1,720,974 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
Karpuzdan (Citrullus vulgaris) saflaştırılan -D-galaktosidazın kinetik özellikleri
No full textKarpuzdan (Citrullus vulgaris) saflaştırılan -D-galaktosidazın kinetik özellikleri incelendi. Kinetik parametreler, doğal ve sentetik substrat olarak rafinoz ve p-nitrofenil--D-galaktopiranozid kullanılarak belirlendi. ve değerleri sırasıyla p-nitrofenil--D-galaktopiranozid için 9,1x mM ve 7,14x ve rafinoz için 7,1x ve 2,9x olarak hesaplandı. Ayrıca D-galaktozun enzim üzerine olan inhibisyon kinetikleri araştırıldı. D-galaktozun neden olduğu inhibisyon tipi kompetitif olarak bulundu.The kinetic properties of -D-galactosidase purified from watermelon (Citrullus vulgaris) were studied. Kinetic parameters were determined by using raffinose and p-nitrophenyl--D-galactopyranoside as natural and synthetic substrates, respectively. The Km and Vmax values were 9.1x mM and 7.14x p.rnolmin-1 for p-nitrophenyl--D-galactopyranoside and 7.1x mM and 2.9x for raffinose. The inhibition kinetics of D-galactose on the enzyme was also investigated. The type of inhibition caused by D-galactose was found as competitive
Domates ve ananas -galaktosidazlarının bazı özellikleri
No full text-Galaktosidaz, -D-galaktozil grubları içeren basit ve kompleks oligo ve polisakkaritlerdeki -D-galaktosidik bağların parçalanmasını katalizler. -D-galaktozil grupları genellikle D-glukoz, D-galaktoz ve sükroz birimlerine bağlıdır ve bitki aleminde yaygın olarak bulunurlar. Bu çalışmada, domates ve ananas -galaktosidazlarının bazı özellikleri çalışıldı. Optimum pH ve sıcaklık değerleri her iki bitki için pH 5.5 ve 45 °C olarak bulundu. Enzim domates için 2.1 x M ve ananas için 2.2 x M değerleri ile tipik bir Michaelis Menten kinetiği gösterdi. Aynı zamanda bazı inhibitörlerin neden olduğu enzim inhibisyonuda araştırıldı. Domates ve ananasın aminoasit bileşimleride verildi.-Galactosidase catalyses the distruption of the -D-galactosidic bond of both simple and complex oligo- and poly saccharides containing -D-galactosyl groups. These groups are usually linked to D-glucose, D-galactose and sucrose and are widely distributed in the plant kingdom. In this work, some properties of -D-galactosidases from tomato and pineapple were studied. The optimum pH and temperature were found as pH : 5.5 and 45°C, respectively for both plants. This enzyme was followed typical Michaelis-Menten kinetics a of 2.1x M for tomato and a of 2.2x M for pineapple. The inhibition of the enzyme caused by some inhibitors was also investigated. Aminoacid composition of tomato and pineapple was also presented
Diamin oksidazın yer fıstığından affinite kromatografisi ile saflaştırılması
No full textDiamin oksidaz, poroz cama histaminin bağlanmasıyla oluşturulan yeni bir affinite materyalinin kullanımıyla yer fıstığı fidelerinden 1865 kat saflaştırılmıştır. Saflaştırılan enzimin 66 kDa'luk moleküler kütleye sahip monomer olduğu belirlenerek histamin için Km ve Vmax değerleri sırasıyla, 1,1x M ve 0.83 mol/mg.dak olarak hesaplanmıştır. Optimum pH ve sıcaklık ise 7.0 ve 37° C dir. Bununla birlikte, bakır bağlayıcı reaktifi dietilditiyokarbamatın, ayrıca karboksil ve imidazol gruplarına spesifik reaktiflerin enzim aktivitesi üzerine etkileri incelenmiştir.Diamine oxidase was purified 1865 fold from roots of peanut seedling using a new affinity material of histamine bound to porous glass. The purified enzyme was found as a monomer with a molecular weight of 66 kD a. The Km and Vmax for histamine were found to be 1.1x M and 0.83 mol/mg.min. respectively. The optimum, temperature and pH were 37°C and 7.0. Furthermore, the effect of various inhibitors such as the copper binding reagent, diethyldithiocarbamate, carboxyl and imidazole group specific reagents on the enzyme activity was also studied
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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