1,721,019 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
Study of the first events of HIV infection in female genital tract tissues : inhibition by antibodies
No full textLors d’un rapport sexuel, le VIH-1, sous forme libre ou associé aux cellules, pénètre dans les tissus du tractus génital féminin. Les premières étapes de l’infection par le VIH-1 dans ces tissus sont très controversées. Afin d’analyser ces premiers évènements impliqués dans la transmission sexuelle, nous avons développé au cours de ma thèse, deux modèles d’infection de cellules isolées de tissu. Nous avons montré que les cellules dendritiques sont préférentiellement infectées et que les anticorps neutralisants inhibent ces premiers évènements de transmission du VIH-1. Dans le cadre de nouvelles stratégies vaccinales, l’inhibition de l’infection des cellules dendritiques sera à considérer afin de prévenir la transmission par voie sexuelle.During intercourse, HIV free virus particles and cell-associated virus, penetrate into the female genital mucosa. The first events following HIV transmission in tissues are still controversial. In order to analyze these first events of transmission, two different models were developed during my thesis: a heterologous model of HIV transmission with cells generated from blood and a model with cells isolated from cervico-vaginal tissues. We found that dendritic cells are preferentially infected. Moreover, neutralizing antibodies efficiently inhibit these first events of HIV transmission. Future HIV prophylactic vaccine design should take into account the potential infection of dendritic cells and new strategies should be developed to prevent the infection of these particular cell populations
Study of HIV-1 transfer from antigen presenting cells to primary CD4 T lymphocytes and inhibition by neutralizing antibodies
No full textLes cellules présentatrices d'antigènes (APCs) présentes dans les muqueuses comptent parmi les première cibles du VIH-1 et participent à sa dissémination dans l'organisme. Durant ma thèse, j'ai étudié le transfert du VIH des macrophages (Mφ) et des cellules dendritiques (DCs) aux lymphocytes T. J'ai montré que ces APCs transfèrent efficacement le virus aux lymphocytes par le biais de différents mécanismes: transfert direct en trans dans les coculture Mφ/T, et transfert en cis (suite à la production de nouveaux virions) dans les DCs/T. Ces deux modes de transfert sont inhibés par les anticorps neutralisants (AcN). De manière intéressante, certains AcN anti-gp120 inhibaient plus efficacement le transfert du VIH dans les cocultures Mφ/T que dans les cocultures DCs/T et l'infection des cellules T par le virus libre. Ces résultats suggèrent que les APCs participent activement au transfert et à la dissémination du VIH et que les AcN sont capable d'inhiber ces différents modes de transfert.Antigen-presenting cells (APCs) present at mucosal sites are among the first HIV-1 target cells and contribute to the spread of infection. During my thesis, I studied HIV transfer from macrophages (Mφ) and dendritic cells (DCs) to CD4-T lymphocytes. I showed that APCs were able to efficiently transfer HIV particles to lymphocytes, but through different mechanisms: Mφ rapidlytransferred HIV by direct trans-transfer, whereas DCs were mainly implicated in cistransfer (after production of de novo HIV). Moreover, I have demonstrated that these two modes of transfer were inhibited by neutralizing antibodies (NAb) in both type ofcocultures. Very interestingly, I showed that anti-gp120 NAb inhibit more efficiently HIV transfer in Mφ/T than in DCs/T cocultures and T cells infection by free viral particles. These findings highlight the major contributions of various mucosal target cells in HIV transfer and demonstrate the potent role of NAb on inhibition of cell-to-cell transfer
Caractérisation de la réponse anticorps protectrice induite après vaccination ou après infection
No full textDifférentes stratégies vaccinales ont été développées afin d’induire une réponse immunitaire efficace contre le VIH. Cependant, de nombreuses questions demeurent. 1) Quel est le profil de la réponse Ab protectrice induite tôt après l'infection? 2) Des anticorps (Abs) inhibiteurs protecteurs peuvent-ils être induits par vaccination? 3) Cette réponse est-elle similaire partout dans le monde ou la variation ethnique ou géographique a-t-elle un impact sur la réponse immunitaire et sur la protection contre l’infection ? Mon travail de thèse montre que, 1) une réponse Ab neutralisante est détectée très tôt après infection, 2) des immunisations avec une enveloppe exprimée dans le contexte du vecteur viral VSV (vesicular stomatitis virus) ou avec un antigène qui cible les cellules dendritiques via un anticorps dirigé contre le CD40 ont permis d’obtenir une réponse Ab forte et maintenue dans le temps. De plus L’infusion lente et prolongée de l’antigène par l’intermédiaire d’une pompe osmotique a permis d’augmenter la réponse Ab induite dans le modèle primate non-humain (NHP). 3) À la fois l’ethnicité (Africains versus Caucasien) et la géographie (USA versus Afrique du Sud) impacte sur la réponse immune induite et donc potentiellement sur la protection vaccinale. Ce travail de thèse a permis de caractériser de manière fine la réponse Ab induite par de nouvelles stratégies vaccinales et démontre que d’autres facteurs impactent la réponse immune induite. Il a fourni des indications sur les approches vaccinales à venir. Nos résultats devraient nous orienter vers le développement de stratégies vaccination plus « personnalisées », en proposant des immunisations individualisées directement adaptées à l'individu et à l'environnement.Different vaccine strategies have been developed to induce an effective immune response against HIV. However, many questions remain. 1) What is the profile of the protective antibody (Ab) response induced early after infection? 2) Can protective inhibitory Abs be induced by vaccination? 3) Is this response similar around the world or does ethnic or geographic variation impact immune response and protection against infection? My thesis work shows that, 1) a neutralizing Ab response is detected very early after infection, 2) immunizations with an envelope expressed in the context of the viral vector VSV (vesicular stomatitis virus) or with antigen targeting dendritic cells via an antibody directed against CD40 allow to obtain a strong and maintained Ab response over time. In addition, the slow and prolonged infusion of the antigen via an osmotic pump made it possible to increase the Ab response induced in the non-human primate (NHP) model. 3) Both ethnicity (Africans versus Caucasians) and geography (USA versus South Africa) influence the induced immune response and therefore potentially vaccine protection. This thesis work allowed to finely characterize the Ab response induced by new vaccine strategies and demonstrated that other factors impact the induced immune response. It provided insights into future vaccine approaches. Our results should guide us towards the development of more “personalized” vaccination strategies, by offering individualized immunizations directly adapted to the individual and the environment
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
Infection of plasmacytoid dendritic cells by HIV : mechanism of antibody-mediated inhibition and study of functional modifications
No full textLes cellules dendritiques plasmacytoïdes (pDC) sont infectées par le VIH-1 et la diminution de leur nombre dans la circulation sanguine est corrélée avec la virémie des patients. Au cours de mes travaux de thèse, nous avons montré que les anticorps neutralisants (AcN) spécifiques du VIH-1 inhibent l’infection des pDC par des isolats primaires de VIH-1. Contrairement aux mDC, le mécanisme d’inhibition de l’infection des pDC est indépendant du RFcγII présent à leur surface. En parallèle, nos résultats indiquent que les pDC produisent de l’interféron-α et d’autres cytokines et chimiokines en réponse au VIH-1, même lorsque l’infection des cellules est inhibée par les AcN. Enfin, nous avons observé l’inhibition du transfert en cis et en trans du VIH-1 des pDC aux lymphocytes T CD4 par les AcN.Dans un contexte d’induction d’AcN par vaccination, l’inhibition de la réplication du VIH-1 dans les pDC associé au maintien de la sécrétion de cytokines pro-inflammatoire par ces cellules pourrait favoriser l’élimination du virus et ralentir sa dissémination dans l’organisme.Plasmacytoid dendritic cells (pDC) are able to replicate HIV-1, and the decrease of pDC number in blood is correlated with HIV-1 viremia in patients. During my thesis, we showed that HIV-1-specific neutralizing antibodies (NAb) inhibited the infection of pDC by HIV-1primary isolates. Unlike mDC, the mechanism of inhibition of pDC infection was independent of FcγRII expressed on these cells. In parallel, our results indicated that pDC produce interferon-α and other cytokines and chemokines in response to HIV-1, even when HIV-1 infection of these cells was inhibited by NAb. Finally, we showed that NAb were able to inhibit HIV-1 transfer in cis and trans from pDC to CD4 T cells.In the context of antibodies induction by vaccination, the inhibition of HIV-1 replication in pDC associated with the maintenance of pro-inflammatory cytokines released by these cells may help to eliminate the virus and impede its dissemination in the body
Characterization of the antibody profile and their inhibitory activities in HIV controllers
No full textLes patients qui contrôlent l’infection par le VIH sans traitement (HIC) représentent un groupe d'étude unique pour identifier des réponses immunitaires associées à ce contrôle. En plus du statut protecteur HLA-B*57, la réponse humorale pourrait participer à ce contrôle. J’ai comparé la réponse B, les caractéristiques isotypiques et les fonctions des anticorps (Ac) des HIC selon leur statut HLA-B*57 et par rapport à des patients chroniques progressant vers la maladie (CP). Chez les HIC, les lymphocytes B (LB) mémoires anti-VIH sont préservés. Des profils d’Ac distincts sont observés entre les HIC HLA-B*57+ (fortes activités médiées par les récepteurs Fc, association entre fréquence des LB et neutralisation), les HIC HLA-B*57- (neutralisation à large spectre) et les CP (forts taux d’immunoglobulines A anti-VIH, forte neutralisation). La caractérisation fine des profils particuliers des Ac nous guidera dans l’élaboration de nouveaux immunogènes capables d’induire une réponse humorale protectrice par vaccination.The patients able to control HIV without treatment (HIV Controllers, HICs) represent a unique study group to identify immune responses associated with this control. In addition to the HLA-B*57 protective status, the humoral response could participate to this protection. I analyzed the B cell response, the isotypic characteristics and the functional antibody (Ab) responses induced in HICs compared to those of chronic progressors. In HICs, the anti-HIV memory B cells are preserved. Distinct Ab profiles are detected between HLA-B*57+ HICs (strong Fc-mediated activities, association between B cell frequency and neutralization), HLA-B*57- HICs (strong neutralization against several strains) and chronic progressors (high levels of anti-HIV immunoglobulins A, strong neutralization). Extensive characterization of the Ab responses in HICs will guide the development of new immunogens able to induce a protective humoral response by vaccination
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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