1,721,135 research outputs found
Characterization of the Iberian pig genome and transcriptome using high throughput sequencing
Full text linkEn aquesta tesis, hem estudiat els patrons de variabilidad nucleotídica del genoma del porc per entendre millor quines forces evolutives l’han afectat. El porc domèstic és una espècie domèstica que presenta una gran variabilitat fenotípica arrel del procés de domesticació i de la formació de races moderna. A més, el porc senglar i altres espècies pròximes encara, avui, estan vives, facilitant, així, la búsqueda de gens candidats que han sofert selecció artificial. El porc, és, també, important en el camp de la biomedicina, com a model de malalties humanes i com a reservori d’organs humans.
En el primer capítol, hem volgut detectar si hi ha hagut selecció artificial en un possible gen candidat per la qualitat de la carn en porcs, la SERPINA6. Per això, hem estudiat la variabilitat nucleotídica de diversos porcs domèstics i senglars de diferents orígens (asiàtics i europeus). L’anàlisis realitzat, però, no ha estat concloent.
En segon lloc, fent ús de les noves tècniques de seqüenciació nova generació, hem pogut estudiar la variabilitat nucleotídica, no només d’un cert gen, sinó de tot el genoma complet d’un porc Ibèric. A més, també, ens ha permès estudiar i caracteritzar el seu transcriptoma. Per dur-ho a terme, hem utilitzat diverses tècniques i metodologies complementàries: ‘whole genome sequencing’, ‘reduced representation libraries’, ‘pool sequencing’ and ‘transcriptome sequencing’. L’estimació de la variabilitat nucleotídica ha estat de 0.7kb-1, un valor gens negligible considerant l’alt coeficient de consanguinitat d’aquesta estirp de porcs. Hem observat, també, que els telòmers tenen una variabilitat més alta que els centròmers, fet que es pot explicar per una taxa de recombinació més alta. A més, el cromosoma X presenta una variabilitat molt més baixa de la esperada respecte als autosomes, causada, segurament per selecció o altres efectes demogràfics.
Per estudiar regions en el genoma sota selecció, hem dividit el genoma en finestres no solapants i calculat diferents test de selecció, tant en un pool de porcs ibèrics, com en un sol individu. Les regions amb excés de polimorfisme i que per tant, podrien estar sota selecció balancejadora, estan enriquides en receptors olfactoris i gens del complex d’histocompatibilitat. En canvi, en regions amb excés de diferenciació i variabilitat molt baixa, no sembla que hi hagi un clar enriquiment en cap funció. De totes maneres, citem possibles gens candidats relacionats amb el metabolisme lipídic, la queratinització, la formació de pèls i el comportament.
Per altra banda, les tècniques de seqüenciació massiva permeten també, detectar variants estructurals basant-se en els patrons del ‘read depth’. D’aquesta manera, hem pogut identificar guanys en el nombre de còpies de certes regions del genoma Ibèric respecte al genoma de referència. En total, hem trobat que 36 Mb del genoma estan afectades i que aproximadament un 5% de gens es troben dins aquestes regions. Així doncs, hem pogut identificar nous paràlogs de gens anotats; la majoria formant part de grans famílies gèniques.
Finalment, hem comparat el transcriptoma de gònades masculines entre dos porcs amb fenotpis molt extrems, un d’Ibèric i un Large White. Els gens diferencialment expressats estan relacionats amb l’espermatogenesis i el metabolisme lipídic, acord amb les seves diferències fenotípiques. També hem pogut identificar nous gens no anotats, long-non-coding RNAs i elements de transposició expressats en aquest teixit
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
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