1,721,046 research outputs found
Commutability of calibration and control materials for serum lipase
Full text linkBackground: To effectively assess and correct for intermethod variability, calibration and control materials (CCMs) must show the same intermethod behavior as patient sera, i.e., they must be commutable. We describe the commutability of selected CCMs for lipase assays, the impact of noncommutability of CCMs in normalizing patient results, and characteristics of reagents that affect assay specificity and commutability. Methods: Lipase was measured in 98 patient sera and in 29 commercial CCMs, with 2 commercial methods using different substrates and with 4 experimental methods using 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6′-methylresorufin) ester as substrate and colipase as cofactor, but differing in the stabilizing proteins used and in the size of the substrate micelles. Results: The noncommutability rate, i.e., the frequency of aberrant intermethod behavior of CCMs in comparison with patient sera, was 27% for liquid CCMs and 47% for lyophilized CCMs. The normalized residuals, measuring the degree of noncommutability, were -2.3 to 2.4 for CCMs with "normal" lipase activity, and -3.5 to 21.7 for CCMs with higher lipase activity. Recalculation of patient results with CCMs as calibrators decreased or increased the original bias according to whether the CCMs were commutable. Conclusions: For the lipase methods in this study, the frequency of noncommutability of CCMs is affected by assay-specific characteristics, including size of substrate micelles and the presence or absence of added proteins
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
Fisiologia: Un approccio integrato, 2° ediz.
No full textVi sono oggi opportunità straordinarie per un proficuo studio delle funzioni del corpo umano. Questo dipende dal fatto che non solo beneficiamo di secoli di studi compiuti da fisiologi che hanno costruito un corpus di conoscenze sulle funzioni dell'organismo umano, ma anche dal fatto che negli anni '70 vi sono stati progressi nel campo della biologia cellulare e molecolare così spettacolari che gli studenti talvolta guardano alla fisiologia come a una materia 'morta', in cui non resta più nulla da scoprire. In effetti, un tempo si pensava che decodificando l'intero genoma umano avremmo avuto la chiave del segreto della vita. Tuttavia, questa visione riduzionista della biologia ha i suoi limiti. Gli organismi viventi sono molto più di una semplice somma di parti, e scoprire le sequenze di geni e proteine in un laboratorio di biologia molecolare non sempre ci chiarisce il loro significato biologico in vivo. Ora, alle soglie del XXI secolo, i biologi molecolari chiedono aiuto ai fisiologi per la comprensione della funzione delle molecole nell'organismo in toto. L'integrazione della funzione a tutti i livelli, dalla molecola all'organismo vivente, è compito precipuo dei fisiologi
Classificazione delle proteinurie: confronto tra elettroforesi capillare e in gel di agarosio
No full textAspetti pre-analitici ed analitici della determinazione automatizzata del lattato del plasma
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