1,720,974 research outputs found
Tetramethylbenzidine staining procedure after starch gel electrophoresis of human haemoglobin
No full textThe purpose of the present work was to increase the stability of tetramethylbenzidine-stained electrophoretic patterns of human haemoglobin through use of a suitable fixing agent. Since haemoglobin examination is quite important in the study of numerous pathologies, in prenatal analyses and in forensic medicine, it was considered worthwhile to attempt to stabilise the specific tetramethylbenzidine-based stain, which is notoriously unstable. The other stain frequently used is amido black 10 B, a generic protein stain, which reveals both haemoglobin and non-haemoglobin bands, hence interpretation of the results can lead to errors and the identification of false pattern heterogeneity. Following several experimental tests we have observed that it is possible to make tetramethylbenzidine-based stains stable by using a suitable fixative. Treatment with the fixing solution prevents the colour from fading, and can keep it intact for over a year. The method also appears promising for studying haemoglobin in a variety of other species of vertebrates
Feologia dell'emissione dei coccidi nel cinghiale (Sus scrofa) nel Parco Naturale della Maremma
No full textGli studi condotti sull'emissione di coccidi in cinghiali del Parco Naturale della Maremma hanno evidenziato un unico ampio picco nel periodo dicembre-maggio. L'assenza di picchi nel periodo dei parti e post-riproduttivo sembra indicare nelle condizioni macro/microclimatiche il principale fattore condizionante l'emissione di coccidi nel cinghiale nell'area di studi
The effects of phenylhydrazine and cobalt chloride on the electrophoretic and isoeletric focusing behaviour of some enzymes in Clarias gariepinus (Clariidae, Teleostei)
No full text1. The electrophoretic and isoelectric focusing behaviour of the LDH, MDH and GPI isozymes of seven tissues was compared for several examples of Clarias gariepinus.
2. Some specimens were injected with phenylhydrazine, others with cobalt chloride while the remaining untreated specimens constituted the normal controls.
3. A significant decrease in, or even the total disappearance of, the activity of the different isozymes considered was found in some tissues from specimens subjected to phenylhydrazine.
4. These results were then correlated to the following: specific enzyme and tissue activity; aerobic or anaerobic metabolism; the nature of the toxic contaminant; hepatic lipogenesis as a defence mechanism in fish; and carbohydrate metabolism
Liver damage due to the administration of phenylhydrazine in Ictalurus sp.
No full textSpecimens of catfish (Ictalurus sp.) were treated with a sublethal dose of phenylhydrazine in order to reveal any liver ultrastructural alterations. Transmission electron microscope ultrastructural analysis of hepatocytes from liver fragments were compared with controls. From the 3rd day after administration of phenylhydrazine, in the vicinity of blood vessels, ultrastructural alterations of the hepatocytes were observed. By day 15 the hepatic parenchyma was manifesting maximum degeneration. An autoregenerative phase of the liver parenchyma was evident on the 21st da
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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