1,720,973 research outputs found
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
A novel treatment for X-linked nephrogenic diabetes insipidus: the secret in secretin?
No full textX-linked nephrogenic diabetes insipidus (NDI) is a disease caused by inactivating mutations of the vasopressin (AVP) type 2 receptor (V2R) gene. V2R inactivation prevents plasma membrane expression of the water channel AQP2 in the kidney collecting duct (CD) cells and impairs the kidney concentration ability.
In the present work we showed that secretin receptor (SCTR) is functionally expressed at the basolateral membrane of the kidney collecting duct cells. Based on this observation, we infused the mouse model of X-NDI with SCT via osmotic pumps for 14 days at a dose of 2.5 mmol/Kg/day. Urinary parameters were not altered in SCT-infused animals. Interestingly, however, SCT significantly increased AQP2 levels in the CD, although the protein was mostly accumulated in the intracellular storage vesicles and hardly detectable at the plasma membrane.
As we previously reported that fluvastatin (Flu) treatment increases AQP2 plasma membrane expression in the CD cells of wt mice, SCT-infused X-NDI mice received a single injection of Flu (50 mg/Kg). Interestingly, during the following 6 hours of observation, the diuresis of mice treated with SCT+Flu was reduced by nearly 90% and urine osmolality doubled. Analysis of the kidneys confirmed that SCT increased intracellular stores of AQP2 and the addition of Flu promoted AQP2 accumulation at the plasma membrane.
Taken together these evidence indicate that the association of SCT and Flu might represent a novel and effective pharmacological treatment for X-NDI
Rosiglitazone promotes AQP-2 translocation in renal cells via a Ca2+ dependent/cAMP independent mechanism (892.9)
No full textPreliminary results by our group showed that exposure to Rosiglitazone (RGZ) induces phosphorylation and apical translocation of AQP2 in mouse collecting duct clone 4 (MCD4) cells. Here we studied the effect of short-term exposure to 50 μM RGZ on cAMP- and Ca2+-mediated signaling pathways, both key players for AQP2-mediated water reabsorption in the collecting duct. Cytosolic Ca2+ and cAMP levels were imaged in real-time in MCD4 cells loaded with Fura-2 or transiently transfected with the EPAC-based fluorescent probe H90, respectively. Physiologically, AQP2 phosphorylation/translocation depends on cytosolic cAMP levels. Nonetheless, cAMP measurements showed that RGZ did not induce significant changes in cAMP levels. Conversely, 20 minutes RGZ stimulation of Fura-2 loaded MCD4 cells induced a large, transient cytosolic Ca2+ peak that was not the result of direct blockade of the SERCA pump since the rate of store empting elicited by CPA in the absence of external Ca2+ was not significantly different in the presence of RGZ. Importantly, removal of external Ca2+ and inhibition of Ca2+ channels with ruthenium red prevented the RGZ-induced increase in cytosolic Ca2+ indicating a prominent role for Ca2+ entry at the plasma membrane. In conclusion, RGZ-induced AQP2 phosphorylation/translocation process is likely initiated by a fast, large extracellular Ca2+ influx most likely via Ca2+-dependent transient receptor potential channels. Further studies to ascertain which cascade of kinases is involved in this scenario are in progress
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
STATINE E SECRETINA COME NUOVO APPROCCIO TERAPEUTICO PER I PAZIENTI AFFETTI DA DIABETE INSIPIDO NEFROGENICO
No full textIl diabete insipido nefrogenico (NDI) è una patologia caratterizzata dalla incapacità del rene a concentrare le urine in risposta all'ormone antidiuretico, vasopressina. Di conseguenza, il paziente NDI produce un enorme volume di urine, è cronicamente assetato ed a rischio di disidratazione. La forma congenita di NDI più comune è dovuta alla mutazione del gene che produce un recettore della vasopressina (V2R) non correttamente funzionante. Il bersaglio della vasopressina nel rene è il canale per l'acqua AQP2 che permette il riassorbimento di acqua renale per cui quando il recettore V2R è alterato, l'AQP2 non è in grado di svolgere il suo ruolo fisiologico. Nessuna delle terapie correnti è risolutiva o mirata al recupero della funzionalità dell' AQP2. Il nostro gruppo ha chiare evidenze sperimentali che le statine, largamente usate nella cura della ipercolesterolemia, sono in grado di recuperare la funzionalità della AQP2 indipendentemente dalla vasopressina. Abbiamo inoltre evidenze sperimentali che la secretina, un ormone coinvolto nel processo digestivo, è in grado di stimolare il proprio recettore SCTR sulle cellule renali producendo un effetto sull’AQP2 simile a quello indotto dalla vasopressina. Di grande importanza è l’osservazione che la somministrazione combinata di fluvastatina e secretina migliora notevolmente i sintomi della malattia nei topi affetti da NDI. Queste osservazioni gettano le basi per l’elaborazione di nuovi interventi terapeutici per il trattamento dell’NDI nell’uomo
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