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Variazioni della dinamica cardiaca da improvviso aumento dell'impedenza aortica all'eiezione ventricolare nel coniglio
No full textThe effect of beta-blockade on the transient increase in coronary vascular resistance resulting from haemorrhage.
No full textAbrupt reduction in aortic blood pressure by haemorrhage in the anaesthetized dog has previously been used to assess the effect of elastic recoil and myogenic properties of the coronary vascular wall on diastolic coronary resistance. Using such assessments this study examines whether beta-blockade influences the magnitude of the effect of the vessel wall on coronary resistance. In two groups of dogs abrupt reduction in aortic blood pressure caused by haemorrhage resulted in an initial increase in diastolic coronary resistance, followed by its decline to the control value. In the first group with intact vagi, beta-blockade resulted in a greater initial increase in resistance and attenuation of its subsequent decline. Vagotomy in the second group did not abolish the effect of beta-blockade on diastolic coronary resistance. The findings suggest that during abrupt reduction in perfusion pressure, beta-blockade and reduction in heart rate and coronary blood flow resulted in a greater elastic recoil of the coronary vascular wall associated with an initial increase in diastolic coronary resistance and attenuation of myogenic properties related to return of diastolic coronary resistance to the control level
The effect of the venom of Bitis gabonica on mesenteric and external iliac blood flow. - A preliminary study in the dog
No full textThe activity of the venom of Bitis Gabonica on mesenteric and external iliac circulation was investigated in four anaesthetized dogs. Venom doses of 0.125, 0.25 and 0.50 mg/kg were injected intravenously with an interval of 30 minutes between two successive injections. Following the first and the second dose, a transient fall of the resistance was observed in the mesenteric and especially in the external iliac vascular bed. Then, mesenteric resistance returned to normal, whereas external iliac resistance increased noticeable above the control value. After the third injection the animals died in a state of severe hypotension. It is note-worthy that during the transient vasodilation, mesenteric flow did not increase proportionally to the reduction of the relevant resistance, owing to the fact that BP fell more than would have been expected from the mesenteric vasodilation. This discrepancy seemed to depend on a more conspicuous reduction of the resistance in other vascular beds as observed in the external iliac circulation
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
Risposta immediata e tardiva dei circoli mesenterico e femorale al veleno di Bitis gabonica
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