1,720,971 research outputs found
Colchicine effect on the permeability of the whole epithelium and of isolated cells of frog skin
No full textThe effect of 2 X 10(-5) M colchicine on epithelial cells isolated from frog skins was investigated. Three hours of treatment with colchicine did not change either Na+ and K+ content of isolated cells or nonelectrolyte permeability. When ADH (50 mU/ml) was added, thiourea uptake values became greater than without the hormone; the same values were found in the cells previously treated with colchicine. Na+ transepithelial transport, measured by means of short-circuit current, was inhibited by the antimitotic agent both under control conditions and after ADH stimulation. These results support the view that colchicine does not directly affect ADH action on membrane permeability, but influences some mechanism that controls ADH action on transepithelial transport. Intercellular junctions appear to be the location of such a mechanism
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
BRUSH-BORDER MEMBRANE ALKALINE-PHOSPHATASE ACTIVITY IN MOUSE PEYERS PATCH FOLLICLE-ASSOCIATED ENTEROCYTES
No full textFacilitated transport of urea across the toad gallbladder
No full textThe toad gallbladder epithelium is much more selective than that of the rabbit especially as to the permeability of two molecules like urea and thiourea. These observations can probably be attributed to different permeation mechanisms of the 2 molecules. Neither active transport nor solvent drag can explain these phenomena. 10(-4) M phloretin strongly inhibits urea movement, but does not alter either thiourea fluxes or isotonic net water transport: these results suggest that a specific mechanism is involved in urea movement. The urea transport shows saturation kinetic which is consistent with the presence of a facilitated mechanism
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
Abitare i territori dell'eccezione. La costruzione del territorio tra pratiche quotidiane e politiche di pianificazione
No full texttesi sostenuta _Una riflessione a posteriori su alcune ricerche condotte in territorio napoletano a partire dall’attività didattica svolta presso la Facoltà di Architettura dell’Università di Napoli Federico II, è l’occasione per indagare lo spazio intermedio tra le pratiche dell’abitare e le politiche della pianificazione, all’interno di un ripensamento dei campi di applicazione degli studi urbani in rapporto all’attualità del territorio. Temi come l’abusivismo, il rischio, lo scarto, il consumo del suolo propongono alla ricerca domande complesse che richiedono inedite attenzioni. Tra queste, l’attenzione alla moltitudine di interventi che, dal basso, introducendosi nei vuoti lasciati dal progetto e dalle regole della pianificazione, modificano per quantità la qualità del paesaggio italiano. Entrare in queste dinamiche, andando oltre la genericità di una pura localizzazione e quantificazione dei fenomeni, può servire ad individuare strategie per governarle.
campo entro il quale la tesi trova argomentazioni/confutazioni _ La tesi si inserisce nell’ambito delle ricerche di questi anni sulla città e sul paesaggio e nell’attualità delle vicende che attraversano oggi il territorio ripercuotendosi sul dibattito disciplinare. Se da una parte lo sfumare l’una nell’altra delle due nozioni di città e di paesaggio ha orientato la discussione teorica in direzioni più inclusive, capaci di accogliere un’attenzione ai paesaggi ordinari e alle pratiche quotidiane, dall’altra vicende, politiche ed emergenze recenti hanno reso evidente il ruolo di queste pratiche nella costruzione dei territori.
prospettive di lavoro _ Le ricerche riguardano la città precaria vesuviana, le periferie della ricostruzione post-terremoto, la città oscura del casertano come tasselli di un ritratto del territorio napoletano costruito a partire dai modi di abitare, sullo sfondo di piani, programmi e progetti pubblici che si muovono a cavallo tra la risposta alle emergenze e la gestione ordinaria. In un luogo nel quale il rapporto tra deroga e regola assume molte diverse sfumature, e quello tra emergenza e quotidiano molte complessità, in un momento nel quale alcune politiche cercano di intercettare le pratiche quotidiane, lo sguardo sull’abitare può essere particolarmente rivelatore di dinamiche e logiche di costruzione del territorio
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