1,720,958 research outputs found
Influenza della temperatura sui parametri elettrici della pelle di rana in situ
No full textDifferenza di potenziale transmembrana e sua corrente di azzeramento sono state determinate sulla pelle ventrale di Rana esculenta inserendo una coppia di elettrodi coassiali nella sacca linfatica ed affacciando a quella una seconda coppia di elettrodi immersa nella soluzione di perfusione esterna. Le soluzioni di perfusione della sacca ed esterna erano identiche (Ringer fosfati pH 7). Nell'intervallo di temperatura tra 6 e 30 °C differenza di potenziale e corrente di azzeramento, espresse come percentuale del valore assunto a 20 °C, aumentano in maniera monotona, con un andamento bifasico non riconducibile ad una retta nel piano di Arrhenius (1/T, lnX). Il rapporto tra queste due grandezze, che rappresenta la resistenza elettrica transmembrana come frazione del valore assunto a 20 °C, segue invece un andamento significativamente rettilineo nel piano di Arrhenius. Il Q10 per la differenza di potenziale (1,25 ± 0,04), la corrente di azzeramento (1.51 ± 0,09) e la resistenza transmembrana (0,83 ± 0,03) da noi rilevati sulla pelle in situ non differiscono molto, nell'intervallo tra 10 e 20 °C, da quelli rilevati dalla letteratura per la pelle isolata. Inoltre l'energia di attivazione per la conducibilità transmembrana in situ (3,4 Kcal/mole°K) è dello stesso ordine di grandezza dell'energia di attivazione per la conducibilità elettrica per la soluzione di perfusione usata. Sembrerebbe quindi possibile ipotizzare che la resistenza elettrica transmembrana determinata come sopra descritto vari in funzione della sola temperatura e non sia correlata alla attività metabolica del substrato
Effetto del pH e della temperatura sulle caratteristiche elettriche della pelle di rana in situ
No full textSi sono misurate la differenza di potenziale transmembrana, la corrente di corto circuito e la resistenza elettrica della pelle addominale di Rana esculenta spinalizzata mediante una coppia di elettrodi doppi coassiali. Si è osservato che aumentando la temperatura da 2 a 35 °C ddp e corrente cc aumentano costantemente, mentre la resistenza diminuisce. Fino a 25 °C il comportamento della pelle in situ è simile a quello della pelle isolata ed i Q10 dei diversi parametri sono confrontabili. Oltre questa temperatura il comportamento è diverso perché non si riscontra alcun massimo di trasporto. Oltre che dal pH delle soluzioni di perfusione esterne, i parametri elettrici dipendono anche dai tamponi utilizzati (carbonati e fosfati tra pH 6 e pH 8) e, almeno per i tamponi citati, la dipendenza dal pH sembra diversa da quella riscontrata da Schoffeniels. Dati preliminari tra pH 3 e pH 9 (tamponi citrato e tris) paiono invece confermare i dati della letteratura, secondo cui ddp e corrente di cortocircuito aumentano con il pH per poi rimanere costanti oltre pH 7,5
Acute effects of salmon, human and porcine calcitonin on plasma calcium and cyclic AMP levels in man
No full text
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
- …
