1,721,042 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
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
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
Radiobiological characterization of craniofacial syndromes
No full textLes syndromes craniofaciaux sont des troubles rares. Ils se caractérisent par des malformations faciales parfois isolées parfois associées à des atteintes systémiques. Des transformations malignes après irradiation de patients atteints de syndromes craniofaciaux ont été sporadiquement décrites mais les mécanismes moléculaires soutenant ces observations restent mal compris. Nous étudions, à travers l'évaluation du transit ATM comme marqueur de radiosensibilité, les cellules ostéoblastiques et fibroblastiques de patients atteints de trois syndromes craniofaciaux majeurs (Mac Cune Albright Syndrom, PIK3CA ROS, ICF syndrom) en comparaison avec des témoins sains. Ces travaux précurseurs, présentent la première caractérisation radiobiologique de syndromes cranio-faciaux et tendent à mettre en valeur une radiosensibilité accrue des patients présentant un syndrome cranio-facial.Craniofacial syndroms are rare disorder. They are characterized by sometimes isolated facial malformations sometimes associated with systemic damage. Malignant transformations following irradiation of patients with craniofacial syndromes have been sporadically described but molecular mechanisms supporting these observations remain misunderstood. We are studying, through the evaluation of ATM transit as a marker of radiosensitivity, the osteoblast and fibroblast cells of patients suffering from three major craniofacial syndromes (Mac Cune Albright Syndrom, PIK3CA ROS, ICF syndrom) in comparison with healthy controls. These pioneering works present the first radiobiological characterization of craniofacial syndromes and tend to highlight an increased radiosensitivity of patients with craniofacial syndrome
Molecular aspects of low-dose radiation therapy in cancer, Alzheimer's disease, and inflammation
No full textAujourd’hui, la radiothérapie la plus courante est basée sur des doses de l’ordre de 2 Gy par fraction, qui visent à détruire les cellules tumorales. La radiothérapie par faibles doses (< 1 Gy/fraction) a quant à elle un effet tantôt destructeur en oncologie, tantôt protecteur pour certaines pathologies inflammatoires ou neurodégénératives comme la maladie d’Alzheimer. Si certaines hypothèses cellulaires ont été formulées, il n’existait cependant pas, à ce jour, d’interprétation moléculaire pour expliquer les différents modes d’action de la LDRT. L’unité Inserm U1296 a développé un modèle moléculaire de réponse individuelle aux radiations basé sur le transit cyto-nucléaire de la protéine ATM : le modèle RIANS (pour radio-induced ATM nucleoshuttling). Après irradiation, les dimères cytoplasmiques d’ATM se monomérisent et diffusent dans le noyau ; les monomères d’ATM reconnaissent alors les cassures double-brin de l’ADN et déclenchent leur réparation. Tout retard de RIANS peut entrainer radiosensibilité (mort cellulaire), radiosusceptibilité (cancer radio-induit) ou radiodégénérescence (vieillissement accéléré). Le modèle RIANS permet également de mieux comprendre des phénomènes spécifiques aux faibles doses tels que l’hormésis et l’hypersensibilité aux faibles doses (HRS). Le but de cette thèse était donc de caractériser, via le rôle central de la protéine ATM, les mécanismes d’action de la radiothérapie par faibles doses pour trois grandes entités nosologiques : le cancer, la maladie d’Alzheimer, et les maladies inflammatoires : – Dans le cas du traitement du cancer, nous avons montré l’importance du phénomène HRS dans la radiothérapie hypo-fractionnée de type stéréotaxique. En effet, en dépit des modèles actuels basés sur la dose totale, il apparait qu’une fraction de radiothérapie stéréotaxique délivre des mini-faisceaux de faibles doses, éligibles au phénomène HRS. Ainsi, pour des tumeurs HRS, l’efficacité anti-tumorale de la radiothérapie stéréotaxique résiderait dans la supra-additivité de faibles doses, entraînant des effets équivalents à de très fortes doses. – Dans le cas de la maladie d’Alzheimer, nous avons mis en évidence une agglutination de la protéine ATM autour du noyau cellulaire, faisant de cette couronne périnucléaire d’ATM un marqueur de vieillissement accéléré. Une irradiation par faibles doses permettrait de monomériser les dimères d’ATM afin de désagréger les couronnes périnucléaires ; l’administration d’un agent radioprotecteur pourrait alors réduire le nombre de cassures de l’ADN et ainsi ralentir la progression de la maladie. – Dans le cas des maladies inflammatoires, des investigations encore en cours suggèrent que les faibles doses apporteraient des monomères d’ATM supplémentaires qui interagiraient avec certaines cytokines dans le cytoplasme, et contribueraient à réduire le nombre de cassures spontanées de l’ADN dans le noyau : les faibles doses produiraient ainsi un effet hormétique bénéfique. Ce travail a permis de : i) confirmer la validité du modèle RIANS ; ii) établir l’état de l’art de la radiothérapie par faibles doses en pratique clinique ; iii) guider le radiothérapeute dans le choix de la technique d’irradiation ; iv) proposer une nouvelle approche diagnostique et thérapeutique de la maladie d’Alzheimer ; et v) apporter des premiers éléments de réflexion sur le plan moléculaire concernant l’effet anti-inflammatoire de la radiothérapie par faibles doses.Today, the most common radiotherapy is based on doses of the order of 2 Gy per fraction, which aim to destroy tumor cells. Low-dose radiotherapy (< 1 Gy/fraction) has an effect that is sometimes destructive in oncology, sometimes protective for certain inflammatory or neurodegenerative pathologies such as Alzheimer's disease. Although certain cellular hypotheses have been emitted, there has not yet been any molecular interpretation to explain the LDRT different modes of action. U1296 Inserm unit has developed a molecular model of individual response to radiation based on the radio-induced ATM nucleoshuttling (the RIANS model). After irradiation, cytoplasmic ATM dimers monomerize and diffuse into the nucleus; ATM monomers then recognize DNA double-strand breaks and trigger their repair. Any delay in the RIANS can lead to radiosensitivity (cell death), radiosusceptibility (radiation-induced cancer) or radiodegeneration (accelerated aging). The RIANS model also provides a better understanding of low-dose specific phenomena such as hormesis and low-dose hypersensitivity (HRS). The aim of this thesis was therefore to characterize, using the central role of ATM protein, the mechanisms of action of low-dose radiotherapy for three major nosological entities: cancer, Alzheimer's disease, and inflammatory diseases: – In the case of cancer treatment, we have shown the importance of the HRS phenomenon in hypo-fractionated radiotherapy of the stereotactic type. Indeed, despite current models based on the total dose, it appears that a fraction of stereotactic radiotherapy may deliver mini-beams of low doses, eligible for the HRS phenomenon. Thus, for HRS tumours, the anti-tumor efficacy of stereotactic radiotherapy would reside in the supra-additivity of low doses, and HRS phenomenon, leading to equivalent effects observed at very high doses. – In the case of Alzheimer's disease, we have demonstrated an agglutination of the ATM protein around the cell nucleus, making this perinuclear crown of ATM a marker of accelerated aging. Irradiation at low doses would make it possible to monomerize the ATM dimers in order to break up the perinuclear crowns; the administration of a radioprotective agent could then reduce the number of DNA breaks and thus slow the progression of the disease. – In the case of inflammatory diseases, preliminary inverstigations (still in progress) showed that low doses would provide additional ATM monomers which would interact with certain cytokines in the cytoplasm, and would contribute to reducing the number of spontaneous DNA breaks in the nucleus: low doses would thus produce a beneficial hormetic effect. These works: i) confirm the validity of the RIANS model at low doses; ii) establish the state of the art of low-dose radiotherapy in clinical practice; iii) guide the radiotherapist in choosing the most relevant irradiation technique; iv) propose a new diagnostic and therapeutic approach to Alzheimer's disease; and v) provide first elements of explanation about the molecular mechanisms of low-dose radiotherapy anti-inflammatory effect
Impact of the ATM nucleoshuttling after ionising radiation exposure : concept of pro-and anti-episkevia
No full textPlus d'un siècle après la découverte des rayons X, les effets biologiques des radiations ionisantes restent encore méconnus. En particulier, une meilleure connaissance des phénomènes liés à la radiosensibilité individuelle permettrait une meilleure prédiction du risque radioinduit tant en ce qui concerne les réactions tissulaires que la formation de cancers.Dans le cadre des recherches menées par le Groupe de Radiobiologie de l'UMR 1052 Inserm (Centre de Recherche en Cancérologie de Lyon), l'accumulation de données radiobiologiques issues de patients radiosensibles a permis d'initier une théorie basée sur le transit cytonucléaire de la protéine ATM. Acteur majeur de la réponse aux radiations ionisantes ATM est muté dans l'Ataxie Telangiectasie, syndrome génétique rare associé à la plus forte radiosensibilité. Plus précisément, les chercheurs du Groupe ont proposé le modèle suivant : l'irradiation produit une monomérisation des formes cytoplasmiques de la protéine ATM. Les monomères d'ATM diffusent dans le noyau pour assurer la reconnaissance et la réparation des cassures double-brin de l'ADN (CDB), dommages-clés de la réponse aux radiations. Tout retard dans ce transit conduirait à une certaine radiosensibilité.Le but de cette thèse est d'identifier d'une part, les protéines (appelées X) qui freinerait ce transit en s'associant à ATM dans le cytoplasme ; d'autre part, les agents chimiques (métaux, pesticides) qui influeraient sur ce processus.Les protéines X identifiées dans le cadre de cette thèse sont notamment la huntingtine, la neurofibromine, la tubérine qui, lorsqu'elles sont mutées, causent respectivement la maladie de Huntington, la Neurofibromatose de type 1 et la Tubéreuse de Bourneville. Les métaux étudiés sont les chlorures d'aluminium, de cuivre, de zinc, de fer, de nickel, de palladium, de cadmium ainsi que le nitrate de plomb, le selenium et le chrome. Les pesticides sont l'atrazine, le glyphosate, la permetrine, le thiabendazole et le pentachlorophénol.Cette thèse introduit la notion de pro-, dys- ou anti-épiskévie, c'est-à-dire la capacité de certains agents, protéines ou drogues à accélérer, ralentir ou interdire le transit cytonucléaire de la protéine ATMMore than a century after the discovery of X rays, the effects of ionising radiation are still misunderstood. In particular, a better knowledge of individual radiosensitivity could lead to a better prediction of radio induced risk of cancer and acute reactions after radiotherapy. As part of the research conducted by the Radiobiology Group of UMR Inserm 1052 (Cancer Research Center of Lyon), the accumulation of radiobiological data from radiosensitive patients allowed to initiate a theory based on the ATM protein transit from cytoplasm to nucleus. ATM a the major actor in the response to ionising radiation and is mutated in Ataxia Telangiectasia, a rare genetic syndrome associated with the highest radiosensitivity. Specifically, the researchers of the Group proposed the following model: irradiation produces monomerization of cytoplasmic forms of ATM protein. ATM monomers diffuse into the nucleus to ensure the recognition and repair of DNA double-strand breaks (DSBs), the key damage response to radiation. Any delay in this transit would lead to radiosensitivity.The aim of this thesis is to identify in one hand, the proteins (called X proteins), which would slow the transit by interracting with ATM in the cytoplasm; on the other hand, chemical agents (metals, pesticides) that would affect this process.X proteins identified in this thesis include huntingtin, neurofibromin, tuberin which, when mutated, cause, respectively, Huntington's disease, Neurofibromatosis type 1 and Tuberous Sclerosis. Studied metals are aluminum, copper, zinc, iron, nickel, palladium and cadmium chlorides, lead nitrate, selenium and chromium. Pesticides are atrazine, glyphosate, permethrin, thiabendazole and pentachlorophenol.This thesis introduces the concept of pro-, dys or anti- episkévia, that is to say the ability of some agents, proteins or drugs to speed up, slow down or inhibit the the ATM nucleoshuttlin
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