1,729,609 research outputs found
Lea protein expression during cold-induced dehydration in the Arctic Collembola Megaphorura arctica
Get PDFThe Arctic springtail Megaphorura arctica (Tullberg, 1876) employs a strategy known as cryoprotective dehydration to survive winter temperatures as low as -25 degrees C. During cryoprotective dehydration, water is lost from the animal to ice in its surroundings as a result of the difference in vapour pressure between the animal's supercooled body fluids and ice (Worland et al., 1998; Holmstrup and Somme, 1998). This mechanism ensures that as the habitat temperature falls, the concentration of solutes remains high enough to prevent freezing (Holmstrup et al., 2002). In M. arctica, accumulation of trehalose, a cryo/anhydro protectant, occurs in parallel with dehydration. Recent studies have identified a number of genes and cellular processes involved in cryoprotective dehydration in M. arctica (Clark et al., 2007; Clark et al., 2009; Purac et al., 2011). One of them includes late embryogenesis abundant (LEA) proteins. This study, together with that of Bahrndorff et al. (2008), suggests that LEA proteins may be involved in protective dehydration in this species
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
DEVELOPMENT OF INSECT-RESISTANT COTTON LINES WITH TARGETED EXPRESSION OF INSECTICIDAL GENE
Get PDFIn order to address biosafety concerns regarding the constitutive expression of foreign genes in crops, we applied a strategy aimed at confining foreign gene expression in insect wounding sites of cotton. For this purpose, a plant expression construct was designed by cloning the AoPR1 promoter (pathogenesis-related protein gene isolated from Asparagus officinalis) upstream from the insecticidal gene cry1Ac. The Turkish cotton cultivar cv. STN-468 was transformed using the Agrobacterium tumefaciens strain LBA4404 containing the recombinant binary vector pRD400 harboring cry1Ac under a wound-inducible promoter. The neomycin phosphotransferase (nptII) gene was used as a selectable marker at a concentration of 100 mg/L. The primary transformants were analyzed for T-DNA integration and expression using standard molecular approaches. The efficacy of insecticidal gene control of the AoPR1 promoter was investigated using leaf bioassays with 2nd instar larvae of Helicoverpa armigera and Spodoptera littoralis. Positive primary transformants from T-0 progeny were further raised under greenhouse conditions to obtain progeny (T-1). The introduced gene was properly inherited and expressed in T-1 progeny. The mechanical wounding of plants resulted in increased cry1Ac protein levels during 0-48 h of the wounding period. The transgenic lines exhibited appreciable levels of resistance against targeted insect pests in the leaf bioassays. The use of a wound-inducible promoter to drive insecticidal gene expression is a valuable insect resistant management strategy as gene expression will remain limited to the insect biting sites of plant and crop, food and environmental concerns can be minimized.TUBITAK (The Scientific and Technological Research Council of Turkey) [2216]The corresponding author is grateful to TUBITAK (The Scientific and Technological Research Council of Turkey) for providing postdoctoral fellowship Code: 2216) to carry out the research activities at University of Ankara. The authors acknowledge Dr. Umut Toprak, Associate Professor, Department of Plant Protection, Faculty of Agriculture, University of Ankara for providing Helicoverpa armigera for our lab bioassays experimen
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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