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VIP-like and GFAP-like immunoreactivities in the chicken brain stem. I. The medulla.
No full textThe aim of the present research is to study the development of spinal ganglia implanted onto chorio-allantoic membrane (CAM), where they are supplied by 'foreign', extraembryonic vessels. Small blocks including a segment of the neural tube and 4 pairs of somites were isolated from the brachial or thoracic or lumbar region (neuromeres C13 - T1 or T3 - T6 or L1 - L4) of thirty 3-day donor chick embryos and grafted on the CAM of as many 10-day host chick embryos. At regular time intervals after grafting, the implants were fixed, embedded in paraffin, serially cross-sectioned and stained. The preliminary results are similar for the ganglia from the 3 regions: they seem to indicate that in the spinal ganglia grafted on the CAM the developing blood vessels do not exert any morphogenetic influence on the substratum; this corroborates results from previous researches (2) on the normally 'in situ' developing ganglia. It is now the author purpose to submit to a careful analysis a datum from the present research: namely, the earlier appearance of the endoganglionic vessels in the brachial and lumbar grafted ganglia than in the thoracic ones
Medullary and mesencephalic neuronal groups reacting to antibodies against VIP, somatostatin and bombesin in adult Gallus gallus domesticus.
No full textThe caudo-cranially intermediate one-third of medullary dorsal region, the periaqueductal grey and the rostro-ventral portion of the midbrain tegmentum of adult chickens were studied in detail by means of the PAP-DAB procedure, to define further the main morphological features of the neuronal populations that in previous studies had shown VIP (Vasoactive Intestinal Polypeptide),-Somatostatin (SRIF)-, and Bombesin-like immunoreactivities. In the medulla, VIP-like immunoreactivity was detected within neuronal bodies and processes and extended down to the cervical spinal cord. SRIF-like immunoreactivity was seen only within nerve cell processes, at least a part of which could be sensitive fibre terminals. Bombesin-like immunoreactivity was observed only within neuronal processes. In the periaqueductal grey, all 3 immunoreactivities were detected within perikarya and neuronal processes, with a higher density cranially. In the rostro-ventral portion of the midbrain tegmentum, VIP-like and Bombesin-like immunoreactivities were detected (the latter being located somewhat more cranially) both in neuronal bodies and in processes. SRIF-like immunoreactivity was found in this region only in long neuronal processes
VIP-like and GFAP-like immunoreactivities in the chicken brain stem. II. The pons and the tegmentum of the mesencephalon.
No full textAn immunocytochemical analysis was performed on the chicken pons and mesencephalon (except the optic tectum) according to the PAP-DAB procedure, to study the distribution here of the neurons reacting to anti-VIP antibodies and the gliocytes reacting to anti-GFAP antibodies. Positive and negative controls were carried out in both the immunoreactions. The VIP-immunoreactive neurons showed a distribution essentially corresponding to that observed in other species by various Authors. They appeared scattered mainly in 3 sites: (a) the subventricular grey between pons and mesencephalon; (b) the periaqueductal grey, up to the diencephalon; (c) the rostro-ventral portion of the mesencephalic tegmentum, up to the diencephalon. Furthermore, some perivascular VIP-immunoreactive neuronal processes were seen. No differences have so far been detected as regards the GFAP-like immunoreactivity distribution, in comparison with the data reported by the authors in the chicken medulla and by others in in the brain stem of some other species
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
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