1,721,100 research outputs found
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
Les acyl-CoA elongases d'allium porrum : solubilisation, purification partielle essais de reconstitution et analyse theorique de leur fonctionnement
No full textSIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
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
De l'implication des radeaux membranaires du plasmalemme dans les phénomènes de signalisation chez les végétaux
No full textDe nombreuses évidences montrent que les membranes plasmiques sont organisées en domaines. Nous avons isolé des microdomaines plasmalemmiques appelés DIM (Détergent Insoluble Membranes) par solubilisation différentielle par les détergents non ioniques à froid. L'hypothèse de travail selon laquelle les acteurs de la signalisation lipidique pourraient être recrutés/exclus de façon dynamique dans les DIM, a été testée par des approches complémentaires. L'analyse globale par spectrométrie de masse du contenu protéique des DIM de cellules BY2 et de racines de Medicago truncatula a montré que la majorité des protéines présentes sont impliquées dans les voies de signalisation, parmi lesquelles des enzymes liées au métabolisme des phospholipides de signalisation (phospholipases Dð et C). Nous avons aussi mis en évidence un enrchissement en phosphoinositides (PIP et PIP2) dans ces DIM végétaux. Nous proposons que "les DIM sont des structures appauvries en phospholipides "de structure" et enrichies en stérols, sphingolipides et phospholipides" de signalisation". L'ensemble des enzymes intervenant dans le métabolisme du PIP et du PIP2 est également présent dans les DIM. A l'inverse les phospholipases D (PLD) qui synthétisent l'acide phosphatidique y sont peu présentes. De plus, les résultats préliminaires montrent que l'activité de certaines enzymes (PLD, PA kinase) présentes dans les DIM fluctue après un traitement hormonal. Ces données suggèrent que les DIM des membranes plasmiques végétales pourraient être impliqués dans les mécanismes de transduction des signaux en compartimentant les voies de synthèse/dégradation des phospholipides "de signalisation".A large body of evidence supports the existence of microdomains in plant plasma membrane. We used differential cold solubilization by nonionic detergents to isolate these plasma membrane microdomains, called Detergent Insoluble Membranes (DIM). We hypothesized that DIM are able to selectively and dynamically recruit or exclude lipids and lipid-utilising enzymes involved in signalling pathways. Several approaches were undertaken to test this hypothesis. First, mass spectrometric analyses show that both tobacco leaf and Medicago truncatula root plasma membrane DIM are enriched in proteins involved in many signaling pathways, like phospholipases Dơ and C. The data clearly indicate that polyphosphoinositides (PIP, PIP2) are also enriched in tobacco DIM. We propose that DIM are membrane domains depleted in "structural phodpholipids" and largely enriched in sterols, sphingolipids and "signalling phospholipids" (PIP, PIP2). Moreover, enzymes involved in polyphosphoinositides metabolism are found in DIM whereas phospholipases D -which synthesize phosphophatidic acid (PA)- seem to be depleted. First results show that both PLD and PA kinase activities fluctuate in DIM after Abscisic Acid Treatment. Taken together these data suggest the involvement of plant plasma membrane DIM in signal transduction by partitioning synthesis and hydrolysis pathways of "signalling phospholipids".BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF
An approach based on the geometric mean of basic quantitative and qualitative bibliometric indicators to evaluate and analyse the research performance of countries and institutions
No full textShort Title : New avenues for the analysis and evaluation of the Research Output of countries and institutionsWe present a straightforward procedure to evaluate the scientific contribution of territories and institutions that combines the size-dependent geometric mean, Q, of the number of research documents (N) and citations (C), and a scale-free measure of quality, q=C/N. We introduce a Global Research Output (GRO-index) as the geometric mean of Q and q. We show that the GRO-index correlates with the h-index, but appears to be more strongly correlated with other well known, widely used bibliometric indicators. We also compute relative GRO-indexes (GROr) associated with the scientific production within research fields. We note that although total sums of GROr values are larger than the GRO-index, due to the non-linearity in the computation of the geometric means, both counts are nevertheless highly correlated. That enables us to make useful comparative analyses among territories and institutions. Furthermore, to identify strengths and weaknesses of a given country or 2 institution, we compute a Relative Research Output count (RROr-index) to tackle variations of the C/N ratio across research fields. Moreover, by using a wealth-index also based on quantitative and qualitative variables, we show that the GRO and RRO indexes are highly correlated with the wealth of the countries and the states of the USA. Given the simplicity of the procedures introduced in this paper and the fact that their results are easily understandable by non-specialists, we believe they could become as useful for the assessment of the research output of countries and institutions as the impact factor is for journals or the h-index for individuals
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
A new approach to the analysis and evaluation of the research output of countries and institutions
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