1,720,965 research outputs found
Caracterización de la expresión de Septina 8 en sistema nervioso central y periférico
No full textLas Septinas son una familia de proteínas GTPasas citoplasmaticas ampliamente distribuidas entre eucariontes y que presentan un alto porcentaje de identidad entre ellas. La presencia de Septina 8 (SEPT8) en proteoma de mielina y su posible función en la barrera a la difusión que mantiene los subdominio de dicha estructura: la mielina compacta y los canales citoplasmaticos, nos llevo a caracterizar su patrón de expresión en sistema nervioso central y periférico
Expresión de marcadores colinergicos, GABAérgicos y glicinergicos en el complejo del istmo en pollos (Gallus-gallus)
Get PDFLa vía visual tectofugal de los vertebrados se encuentra particularmente desarrollada
en las aves y ha sido asociada a procesos de orientación y atención espacial. El téctum
óptico (TeO, colículo superior en mamíferos) es el núcleo central de esta vía y el
principal centro visual del cerebro de las aves. La actividad visual que recibe el téctum
óptico desde la retina, gatillada por algún estimulo en movimiento, evoca señales
sincronizadas de retroalimentación (feedback) desde dos núcleos del istmo, el isthmi
pars parvocelullaris (lpc) y el isthmi pars semilunaris (SLu), cuyos terminales axónicos
columnares aunque confluyen en toda la extensión tectal, ramifican densamente en
capas tectales alternadas. Las señales de feedback generadas por lpc parecen actuar
como un foco atencional que potencia de manera selectiva la propagación de la
entrada (rnpuf) retiniana desde el téctum hacia áreas visuales superiores. Se ha
propuesto que dicha modulación del flujo visual ocurre por medio de liberación de
acetilcolina en las capas tectales superiores, la cual actúa a nivel pre-sináptico sobre
receptores nicotÍnicos en los terminales axónicos de las células ganglionares de la
retina, alterando/modulando la liberación de glutamato por parte de estos terminales. Si
bien se considera que lpc y SLU son núcleos colinérgicos, ya que muestran inmuno-reactividad contra la enzima colinacetil transferasa (ChAT), existen informes
contradictorios con esta postura, como la posible liberación de glicina o la inmuno-reactividad anti-GABA, que levantan dudas acerca de la neuroquímica de este núcleo.
Si el núcleo lpc presenta un fenotipo neuroquímico distinto al actualmente considerado,
podría llegar a cambiar la visión de como lpc estaría ejerciendo el control/modulación
tecto-talámico, lo que abriría deferentes posibilidades acerca de su participación en el
control del flujo visual tectofugal. En el presente trabajo revisamos la identidad
neuroquímica de los núcleos del istmo en el pollo mediante ensayos de hibridación in
sltu para el marcador de neuronas colinérgicas VAChT, junto con otros dos marcadores
involucrados en la liberación de GABA y glicina: el transportador vesicular de
aminoácidos inhibitorios (VIAAT) y el transportador de glicina (GLYT2). Encontramos
que el núcleo lpc no expresa los ARN mensa.leros para VIAAT y GLYT2, lo que indica
que sus neuronas son incapaces de liberar GABA y/o glicina. Sorprendentemente,
aunque ambos núcleos, lpc y SLu, mostraron ser inmuno-positivos para ChAT, solo
SLU resultó expresar de manera potente los ARN mensajeros para VAChT, mientras
que en lpc la expresión de dicho marcador resulto ser indetectable. Estos resultados
descartan que lpc opere mediante funciones neuroquímicas GABAérgicas y
glicinérgicas y sugieren la posibilidad de una liberación no-vesicular de acetilcolina por
parte de este núcleoVersión original del auto
Caracterización neuroquímica y sináptica del circuito istmo-tectal en la vía tectofugal de aves
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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
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