1,721,067 research outputs found
SHELL (BIVALVIA, PTERIOMORPHIA)
No full textBiominerals are organo-minerals structures produced by living systems. Since the Cambrian, they contribute to the adaptation of living organisms to different environments by fulfilling a variety of functions that go along with adapted morphologies. One of the aims of biomineralization is to understand how organisms "sculpt" these complex morphologies at nano and molecular scales: we know that occluded organic matrix (OM) proteins influence the lattice parameters of biominerals [1] and that many of them strongly interact with the mineral phase in in vitro assays, but their exact roles are still to be known. The aim of my PhD is to understand the complex relationships between the organic and mineral phases. In the present study, I discuss the case of the Mediterranean fan mussel Pinna nobilis.
Like most molluscs, Pinna nobilis, the fan mussel, envelops its soft body with a highly ordered shell composed of two mineralized layers: the internal one is nacreous made of aragonite, while the outer one is made of long calcitic prisms that grow perpendicularly to the surface of the shell. This latter shell layer comprises an assemblage of insoluble periprismatic matrix (proteins + saccharides) and very acidic "intracrystalline" proteins and sugars, together with pigments. This shell layer was submitted to:
Morphological and spectral characterization: To unveil the complex and hierarchical structures of biomineral models, we have acquired high-resolution 2D and 3D images by using different microscopic and spectro-microscopic techniques at Synchrotron SOLEIL. Under UV light, we have recently evidenced a striking luminescent pattern - never observed before - in relation to pigments.
Biochemical analysis of organic matrix: we have analyzed the intra and inter-prismatic OM by gel electrophoresis, ELISA test and western blot. Moreover, a transcriptome constructed from the mantle tissues has helped us to identify by proteomics a large set of proteins associated to the formation of prisms.
The significance of our results is discussed here. Our data tend to show that the formation of "simple prisms" is an extremely regulated process, which requires several molecular actors
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
Identification non-destructive des vernis des oeuvres d'art par fluorescence UV
No full textFor centuries, varnishes applied on works of art have been prepared with natural resins. These natural products degrade in the course of time and consequently modify the visual aspect of the work of arts. Thus, restorers must reduce the layer of varnish using solvents chosen according to the nature of varnish and not deteriorating the pictorial layer. The identification of varnishes is thus essential for the choice of the apt solvent. Until now, that identification was obtained by chemical analyses using samples. With UV fluorescence, we developed a technique allowing nondestructive identification of varnishes which can be carried out in-situ and giving results in real time. This method is based on the comparison of the spectrum of fluorescence of an unknown varnish with those of a database of recent, artificially and naturally aged varnishes of reference. Examples of identification of varnishes on several works of art are presented in this work. In parallel, the first step toward the separation and the identification of principal the fluorophores contained within the resins were carried out by liquid chromatography coupled with the electrospray mass spectrometry.Depuis des siècles, les vernis apposés sur des œuvres anciennes sont constitués de résines naturelles. Ceux-ci se dégradent au cours du temps et modifient l'aspect visuel de l'œuvre. Les restaurateurs doivent donc alléger la couche de vernis à l'aide de solvants choisis selon la nature du vernis et n'altérant pas la couche picturale. L'identification des vernis est donc essentielle pour le choix solvant. Elle était, jusqu'ici obtenue par des analyses chimiques faites à partir de prélèvements. A l'aide de la fluorescence UV, nous avons développé une technique d'identification non-destructive des vernis, réalisable in-situ et donnant des résultats en temps réel. Cette méthode s'appuie sur la comparaison du spectre de fluorescence d'un vernis inconnu avec ceux d'une base de données de vernis de référence récents, vieillis artificiellement ou naturellement. Des exemples de reconnaissance des vernis sur plusieurs œuvres d'art du patrimoine sont présentés. Parallèlement, la séparation et l'identification des principaux fluorophores contenus au sein des résines ont été réalisées par chromatographie liquide couplée à la spectrométrie de masse utilisant l'ionisation par électrospray
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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