1,720,963 research outputs found
The Glial response to injury in the developing brain
No full textDespite major advances in techniques of imaging the human brain, there is still uncertainty about the exact time at which many fetal and neonatal brain lesions occur. Pathological appearances do not always help owing to the difficulty in establishing the exact sequence of the tissue response to brain injury. In the first part of the present study, 179 post-mortem human brains from fetal, neonatal and infant cases (varying in age from the first trimester of gestation to children of 7 years of age) were examined macroscopically and by light microscopy. Of these brains, 69 showed no pathological abnormality, 98 had hypoxic/ischaemic lesions, 5 displayed congenital abnormalities and 4 brains showed venous infarcts. Hypoxic/ischaemic brain damage was the most common lesion in this series and affected fetuses from 16 weeks of gestation to term and infants who had survived to 19 months of age. This group was ideal for studying the glial, inflammatory and blood vessel responses to brain damage in fetal and early postnatal life. Light microscopical studies included immunocytochemistry for Glial Fibrillary Acidic Protein (GFAP) - an astrocyte marker, S-100 protein - a glial marker, fibronectin - a marker for the connective tissue in blood vessel walls, factor VIII Related Antigen - an endothelial cell marker and S22 - a macrophage marker. The expression of these markers was also assessed in the normal developing human brain. The second part of the study was designed to test the hypothesis that GFAP could be induced by injury to the fetal brain before the time at which it appears during normal fetal development. Cold lesions were inflicted upon fetal and neonatal rat brains and the glial response was examined by the immunoperoxidase staining technique. The expression of glial and mesenchymal cell markers in developing uninjured fetal and neonatal animals was also assessed. The results of this combined human and experimental study suggest that: a) The expression of GFAP by developing astrocytes can be induced by injury to the CNS in an area and at a time at which it is not observed in the normal developing brain b) In the human brain, formation of glial scar tissue occurs as early as 22 weeks of gestation in fetuses with hypoxic/ischaemic brain damage c) After 22 weeks gestation in man and 16 day gestation in the rat, the formation of glial scar tissue depends on the period elapsing from the time of injury to the moment of death, irrespective of age. d) The glial response is similar in different types of injury and in brains injured in utero or in postnatal life. Following this study a more logical approach has been adopted for the assessment of fetal and neonatal brain damage. (DX86661)</p
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
A newly recognized autosomal recessive syndrome with abnormal vertebral ossification, rib abnormalities, and nephrogenic rests
No full text- …
