1,720,964 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
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
Association between BUN to creatinine ratio, ultrasonographic congestion and neurohormonal activation in outpatients with heart failure
No full textBackground. Blood urea nitrogen to serum creatinine ratio (BUN/sCr) is considered a marker of neurohormonal activation related to arterial underfilling, and therefore as a guide to taper or withdraw diuretic treatment. However, the association between BUN/sCr and prognosis is stronger in patients with heart failure with preserved ejection fraction (HFpEF), who are known to exhibit a reduced neurohormonal activation as compared with patients with heart failure and a reduced ejection fraction (HFrEF); moreover, kidney dysfunction in HF is increasingly recognized to be due to backward failure (i.e. venous congestion) than to forward failure (i.e. impaired cardiac output). The aim of this study was to assess the relationship between BUN/sCr, ultrasonographic congestion and neurohormonal activation in outpatients with heart failure.
Methods. We studied 473 consecutive patients with HF; we performed a complete echocardiographic exam, comprehensive of venous and pulmonary congestion evaluation, three-dimensional echocardiography, and a thorough biohumoral assessment. We elaborated a congestion score consisting of increased inferior vena cava (IVC) diameter, discontinuous renal venous flow (RVF), and increased lung B-lines. Study population was divided in tertiles according to BUN/sCr.
Results. Patients with higher levels of BUN/sCr displayed a significantly increased ultrasonographic congestion (P = 0.021) and a more pronounced neurohormonal activation, indicated by renin and aldosterone levels (renin: 26.4, interquartile range [IQR] 9.2-71.3, mIU/L in the highest tertile vs 14.1, IQR 4.6-38.9, mUI/L in the lowest tertile, P = 0.013; aldosterone: 3.2, IQR 8.7-18.3, ng/dL vs 10.1, IQR 6.5-15.0, ng/dL). When examining single items of congestion score, only discontinuous RVF reached statistical significance (P=0.031), with higher BUN/sCr being associated with a more impaired RVF.
Conclusion. Higher levels of BUN/sCr are associated with systemic venous congestion, in particular with impaired renal venous flow, and with enhanced neurohormonal activation. The decision to taper or withdraw diuretic treatment cannot be taken without thorough and seriated ultrasonographic assessments of congestion
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
L'influenza di Sirt-1 sulla disfunzione endoteliale nell'obesità è mediata dall'attività della ossido nitrico sintasi endoteliale e dal controllo dello stress ossidativo di origine mitocondriale
No full textL’obesità è divenuta, negli ultimi decenni, una condizione sempre più prevalente fino ad assumere i caratteri di una vera e propria pandemia. Si tratta di una condizione associata strettamente allo sviluppo di malattie neoplastiche, malattie neurodegenerative, ma soprattutto diabete mellito e patologie cardiovascolari.
La malattia cardiovascolare rappresenta la prima causa di morte nel mondo occidentale, causando il 45% circa di tutte le morti in Europa.
Il substrato anatomopatologico che, nella maggior parte dei casi, giustifica la relazione tra i fattori di rischio descritti e la malattia cardiovascolare è rappresentato di fatto dall’aterosclerosi,
una condizione di ispessimento e perdita di elasticità delle arterie caratterizzata dalla presenza di placche ateromatose.
L’ipotesi patogenetica dominante è quella della reazione al danno, per cui l’aterosclerosi sarebbe una risposta infiammatoria riparativa della parete arteriosa a un danno a carico dell’endotelio; la progressione della lesione avviene per via delle continue interazioni tra lipoproteine modificate, macrofagi derivati dai monociti, linfociti T e normali costituenti della parete arteriosa.
Secondo la teoria della reazione al danno, il danno endoteliale rappresenta il momento patogenetico iniziale dell’aterosclerosi; si è osservato, peraltro, che le lesioni precoci originano in sedi con endotelio morfologicamente indenne. Questo ha suggerito che il processo aterosclerotico non debba necessariamente prevedere un danno a carico dell’endotelio, ma che anche un semplice cambiamento della funzione delle cellule endoteliali, come risultato dell’esposizione a fattori di rischio cardiovascolare, potrebbe promuovere il processo aterosclerotico.
Col termine di “disfunzione endoteliale” ci si riferisce a un fenotipo alterato dell’endotelio caratterizzato da ridotta biodisponibilità di NO, aumentato stress ossidativo, elevata espressione di fattori pro-infiammatori e pro-trombotici, e alterata vasoreattività a stressors endotelio-dipendenti.
È noto da tempo che l’obesità è associata con una disfunzione endoteliale caratterizzata da una ridotta disponibilità di NO e da uno squilibrio tra il sistema di NO e il sistema di ET-1, e sembra che il collegamento tra lo squilibrio del sistema del NO e la disfunzione endoteliale sia rappresentato dallo stress ossidativo.
Negli ultimi anni, sono stati compiuti numerosi studi, su modelli animali e sull'uomo, sulle sirtuine, una famiglia di istone deacetilasi che sembrano avere un ruolo protettivo dalla patologia cardiovascolare. In particolare, Sirt1 è in grado di attenuare i processi infiammatori e lo sviluppo di stress ossidativo in diversi modi, alcuni dei quali coinvolgono i mitocondri e la proteina p66Shc
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