1,721,025 research outputs found
Resenha: SILVA, Giovani José da & COSTA, Anna Maria Ribeiro F. M. da. Histórias e culturas indígenas na educação básica. Belo Horizonte, Autêntica, 2018.
Full text linkResenha do livro:SILVA, Giovani José da & COSTA, Anna Maria Ribeiro F. M. da. Histórias e culturas indígenas na educação básica. Belo Horizonte, Autêntica, 2018
Resenha: SILVA, Giovani José da; COSTA, Anna Maria Ribeiro F.M. da. Histórias e culturas indígenas na Educação Básica. Belo Horizonte: Autêntica, 2018. (Coleção Práticas Docentes).
No full textResenha do livro:SILVA, Giovani José da; COSTA, Anna Maria Ribeiro F.M. da. Histórias e culturas indígenas na Educação Básica. Belo Horizonte: Autêntica, 2018. (Coleção Práticas Docentes)
Allopregnanolone and pregnanolone are reduced in the hippocampus of epileptic rats, but only allopregnanolone correlates with the seizure frequency
No full textBackground: Neurosteroids modulate epileptic activity by interacting with the γ-aminobutyric acid type A receptor, but their brain levels are still undetermined. Objectives: We aimed to establish levels of neurosteroids in the neocortex and hippocampus by liquid chromatography–mass spectrometry in epileptic rats. Methods: Kainic acid-treated rats were continuously monitored up to 9 weeks to determine the seizure frequency by video electrocorticography (n=23), and compared to age-matched controls monitored in the same manner (n=11). Results: A reduction in allopregnanolone (-50%; p<0.05, Mann-Whitney test) and pregnanolone levels (-64%; p<0.01) was found in the hippocampus, whereas pregnenolone sulfate, pregnenolone, progesterone, and 5α-dihydroprogesterone were nonsignificantly reduced. No changes were found in the neocortex. Moreover, allopregnanolone (but not pregnanolone) levels were positively correlated with the seizure frequency (r2=0.4606, p<0.01). Conclusions: These findings indicate a selective reduction in hippocampal levels of 3α-reduced neurosteroids. This reduction was partially mitigated by seizures in the case of allopregnanolone
Seizure progression is slowed by enhancing neurosteroid availability in the brain of epileptic rats
Full text linkTrilostane is a 3β-hydroxysteroid
dehydrogenase/Δ5-4
isomerase inhibitor able to
produce a manyfold increase in brain levels of various neurosteroids, including
allopregnanolone. We previously found that treatment with trilostane can slow
down epileptogenesis in the kainic acid (KA) model of temporal lobe epilepsy. It
is unknown whether trilostane may have a similar effect on the progression of
epilepsy severity, as observed in KA-treated
rats. Consequently, we investigated
the effects of trilostane (50 mg/kg/day, 1 week) in epileptic rats, given 64 days
after KA administration. Seizures were monitored by video-electrocorticographic
recordings before and during the treatment with trilostane or vehicle (sesame
oil), and neurosteroid levels were measured in serum and cerebral tissue using
liquid chromatography–electrospray tandem mass spectrometry after treatment.
Pregnenolone sulfate, pregnenolone, progesterone, 5α-dihydroprogesterone,
and allopregnanolone peripheral levels were massively increased by trilostane.
With the only exception of hippocampal pregnenolone sulfate, the other neurosteroids
augmented in both the neocortex and hippocampus. Only pregnanolone
levels were not upregulated by trilostane. As expected, a significant increase in
the seizure occurrence was observed in rats receiving the vehicle, but not in the
trilostane group. This suggests that the increased availability of neurosteroids
produced a disease-modifying
effect in the brain of epileptic rats
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
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