1,721,152 research outputs found
Identificació dels factors genètics que determinen la variabilitat dels nivells de FVII a la població espanyola. Resultats del Projecte GAIT
Get PDF[cat] La trombofilia és la tendència genètica al tromboembolisme venós. Amb la finalitat d'aprofundir en les bases genètiques de la trombofília hereditària, l'objectiu principal d'aquesta tesi és la identificació dels factors genètics que determinen la variabilitat dels nivells de FVII a la població espanyola. En primer lloc, es va calcular l'heretabilitat dels nivells de FVII en un 53%, i mitjançant una anàlisi global del genoma es va localitzar el gen responsable de la variabilitat dels nivells de FVII en la zona 13q, just on es localitza el gen estructural del FVII (F7). Aquest resultat indica que els factors genètics que determinen la variabilitat de FVII en plasma es troben en el gen estructural. A continuació es va realitzar una anàlisi genètica exhaustiva i es van obtenir 49 posicions polimòrfiques al llarg del gen (F7), la majoria canvis d'una sola base (SNPs). A més, mitjançant una anàlisi de l'organització haplotípica de la variació en la seqüència del (F7), es va observar que existeixen tres clars llinatges d'haplotips que s'han mantingut paral·lelament en la població espanyola per selecció estabilitzadora, molt probablement per un avantatge dels individus heterozigots. L'anàlisi d'associació entre aquests llinatges i els nivells de FVII indica que un d'ells, caracteritzat pels al·lels [-670C, -630G, -402A] està associat a nivells elevats en la població, i un altre, caracteritzat pels al·lels [-2989A, -401T, -323ins10, -122C] està associat a nivells reduïts. Les anàlisis posteriors de transfecció in vitro amb els diferents al·lels utilitzant un sistema reporter GFP (Green Fluorescent Protein) van permetre determinar que les variants -323ins10 i -122C tenen un efecte reductor sobre els nivells de proteïna, i que la variant -402A provoca un augment significatiu dels nivells de FVII. Finalment, la nova variant -2989A incrementa també de forma molt significativa els nivells d'expressió. Aquests resultats es confirmen a més en un estudi cas-control amb pacients amb trombosi venosa profunda, així com en dues famílies amb deficiència de FVII. El disseny, l'estratègia i la metodologia emprades són un bon exemple de com localitzar i identificar loci implicats en caràcters complexes.[eng] There is a definite genetic predisposition to venous thromboembolism. The levels of FVII in plasma has been clearly implicated in thrombophilia. The aim of this thesis was to identify and characterize the genetic factors that determine the variability of FVII plasma levels in the Spanish population. First, the heritability of FVII levels was calculated as 53%indicating a substantial genetic component. A Genome Wide Scan allowed the localization of the responsible gene on the long arm of chromosome 13, exactly where the FVII "(F7)" structural gene has been located. This indicates that the genetic factors that determine FVII variability are localized in the structural gene. Second, from an exhaustive genetic analysis, we obtained 49 polymorphisms (variants) in the "F7" gene. Further, by an analysis of sequence variations and haplotype organization, three main haplotype lineages were detected that have been maintained presumably by balanced selection, probably due to an advantage of heterozygous individuals. The association analysis among these lineages and the FVII levels indicates that one of these lineages, containing allelic variants [-670C, -630G, -402A] was associated with elevated FVII levels. Also, another lineage, containing allelic variants [-2989A, -401T, -323ins10, -122C] was associated with reduced levels of FVII. Posterior functional analyses of "in vitro" transfection of the different variants in a "reporter" system with GFP "(Green Fluorescent Protein)" showed that allelic variants -323ins10 i -122C significantly reduce expression levels while allelic variant -402A significantly increases them. The new allelic variant -2989A also increases expression levels significantly. Finally, these results have been confirmed in a case-control study with patients with deep venous thrombosis and in a study of two families with a FVII deficiency. The strategy and methodology of the present work are good examples of how to localize and identify genes implicated in complex human diseases
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
Estudis funcionals dels polimorfismes del promotor del F7
Get PDFEls nivells en sang del Factor VII (FVII), una proteïna essencial de la cascada de la coagulació sanguínia, són un factor conegut de risc cardiovascular. Els nivells d'aquesta proteïna estan determinats pel promotor del gen que la codifica, i aquest promotor presenta distintes variants. Aquest estudi ha investigat com es relacionen les diferents variants amb els nivells de proteïna en sang.Los niveles en sangre del Factor VII (FVII), una proteína esencial de la cascada de la coagulación sanguínea, son un factor conocido de riesgo cardiovascular. Los niveles de esta proteína están determinados por el promotor del gen que la codifica y este promotor presenta distintas variantes. Este estudio ha investigado cómo se relacionan las diferentes variantes con los niveles de proteína en sangre
Estudis funcionals dels polimorfismes del promotor del F7
No full textEls nivells en sang del Factor VII (FVII), una proteïna essencial de la cascada de la coagulació sanguínia, són un factor conegut de risc cardiovascular. Els nivells d'aquesta proteïna estan determinats pel promotor del gen que la codifica, i aquest promotor presenta distintes variants. Aquest estudi ha investigat com es relacionen les diferents variants amb els nivells de proteïna en sang.Los niveles en sangre del Factor VII (FVII), una proteína esencial de la cascada de la coagulación sanguínea, son un factor conocido de riesgo cardiovascular. Los niveles de esta proteína están determinados por el promotor del gen que la codifica y este promotor presenta distintas variantes. Este estudio ha investigado cómo se relacionan las diferentes variantes con los niveles de proteína en sangre
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